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August 30

Bouncing babies...?

Hello All!

I just heard that "dandling" or bouncing a baby upon one's knee can cause great damage, as the child's brain will wiggle about...? This sounds a bit off to me, and I haven't the least idea were I would find out whether or not this is true. Any help would be very much appreciated! Russia Moore 01:52, 30 August 2006 (UTC)[reply]

See shaken baby syndrome. --Kainaw ^(talk) 02:03, 30 August 2006 (UTC)[reply]

Obviously a an overly vigorous bounce could casue damage, so just use some common sense and don't go nuts with the baby. It makes a difference here too what age of baby we are talking about. If they aren't old enough to have developed the muscles that support the head, then you should be supporting the head no matter what you do. Older babies are different, but again, the amount of force is the issue. pschemp | talk 02:08, 30 August 2006 (UTC)[reply]

Just bounce him/her carefully. it nver dud mu ayn dmagew (apart from the slight spelling problem 8-)--Light current 02:28, 30 August 2006 (UTC)[reply]

Thanks so much, I should have thought of shaken baby syndrome (I was just reading about child abuse cases today)! Of course I assumed that most people have the common sense not to vigorously shake an infant, but sadly I suppose this is not the case. Anyhow, my baby brother never seemed to suffer from playing horsey... But now when I next get ahold of a bouncable baby I will be able to rest my mind that I am not dashing parental hopes of Ivy Leagues :P -Russia Moore 02:43, 30 August 2006 (UTC)[reply]

I think its the acceleration or shock you have to watch.--Light current 02:46, 30 August 2006 (UTC)[reply]

When I read of "shaken baby " syndrome I picture some foolish and/or evil caregiver or parent grabbing the baby by the shoulders and shaking it to and from them because they are angry it is crying, so its head flops back and forth from the chest to the back, causing impacts of the brain against the skull. I do not picture someone bouncing the little one on the knee to a tune. Edison 03:58, 30 August 2006 (UTC)[reply]

Yes but read my previious post!--Light current 04:02, 30 August 2006 (UTC)[reply]

Russia, out of curiosity, did you hear that from the comment in the A.Word.A.Day mailing list? —D a niel (‽) 11:15, 30 August 2006 (UTC)[reply]

I did indeed :) Russia Moore 02:38, 31 August 2006 (UTC)[reply]

Yay. —D a niel (‽) 08:37, 31 August 2006 (UTC)[reply]

Noise Cancelling Within Commercial Aircraft

I recall being told that a low fequency sound is transmitted in commercial aircraft to cancel the noise of, for example, crying babies. I don't mean noise cancelling headphones (as referred to in a question above) but a sound that is transmitted throughout the whole passenger area.

Does this exist?Downunda 03:42, 30 August 2006 (UTC)[reply]

I think you may be thinking of the masking effect of white noise--Light current 03:58, 30 August 2006 (UTC)[reply]

You might go for pink noise as well. I'm not sure I would refer to any of them as being low frequency, though. —Bromskloss 08:23, 30 August 2006 (UTC)[reply]

Noise similar to that from air handling equipment is sometimes used in offices to mask audibility of speech. Otherwise, in an open plan office, one might hear conversations 50 feet away or more. Sometimes a new installation of masking noise is made over a weekend or holiday. If it is initially turned up too loud, workers may call the janitor to complain of a toilet running without shutting off. Edison 04:01, 30 August 2006 (UTC)[reply]

If thats a swishing noise you describe, its white noise.--Light current 04:04, 30 August 2006 (UTC)[reply]

Or pink noise. Ok, mabye white noise is swish and pink noise more like swosh. Listen for yourselves: white pink I think I've hear about pink noise being used for precisely this masking purpose. —Bromskloss 19:44, 30 August 2006 (UTC)[reply]

induced gravitational effects

in the presence of a magnetic field, charge tends to orbit

if charge is constrained to orbit, magnetic field effects are manifested

in the presence of mass, light is deflected (tends to orbit)

Q: is it the case that if light is constrained to orbit, gravitational effects will manifest? [say, coherent light in a fibre-optic coil, geometry such that the content of adjacent loops are in phase] 05:00, 30 August 2006 (UTC) 71.113.160.42

You may be looking for someting like geon? — [Mac Davis] (talk) (Desk|Help me improve)

It's an interesting theory. Nothing in the current understanding of physics predicts such an effect, but we know that we have been unable to combine general relativity and quantum electrodynamics in a coherent fashion, so why not? --Lambiam ^Talk 05:23, 30 August 2006 (UTC)[reply]

If light is constrained to 'orbit' no light can escape because its velocity is less than the escape velocity. This sounds like a black hole--Light current 11:34, 30 August 2006 (UTC)[reply]

Perhaps the stellar object is surrounded in a cloud of Bose–Einstein condensate? freshofftheufo ΓΛĿЌ 14:22, 30 August 2006 (UTC)[reply]

I agree with Lambiam that it's an interesting theory, but as the old saying goes, "There is nothing new under the sun". In fact, at several talks given by Dr Karl Kruszelnicki, he has shown footage of an experiment he took part in that sounds like practically the same idea - by forcing light to travel in a tight orbit (I forget the details of how), they were hoping to observe some relativistic-style effects. Unfortunately, any effects that may have been present were too small for their apparatus to detect, and if their theory had worked there should have been some damn impressive results. Confusing Manifestation 14:03, 30 August 2006 (UTC)[reply]

What does benzoxycamphor mean?

ATTENTION: The REAL longest word in the English language is triskaidekaphobia, meaning fear of the number 13. =)

At Longest word in English benzoxycamphors is said to be potentially the highest-scoring word in Scrabble. Web searches don't reveal any more than it being a chemical compound. I wonder if someone could explain what sort of chemical it is, and where it might be found and/or used. Thanks. KeithD 06:43, 30 August 2006 (UTC)[reply]

Perhaps you mean benzyloxycamphor? – Clockwork Soul 06:58, 30 August 2006 (UTC)[reply]

I do mean benzoxycamphor, as at [1], simply because benzyloxycamphors wouldn't fit on a Scrabble board. Could benzoxy... be another name for benzyloxy...? KeithD 07:32, 30 August 2006 (UTC)[reply]

conceivably, compounds are called all sorts of things under the old system. i'd be surprised if it was a legal word however for the purposes of scrabble. Xcomradex 08:38, 30 August 2006 (UTC)[reply]

For what it's worth, pharmaceutical sedatives such as valium, xanax, rivotril, and ativan all fall into the pharmaceutical category of benzodiazepines. I'd suspect that the chemical you're speaking of is somehow related. Loomis 11:17, 3 September 2006 (UTC)[reply]

They're not related at all. Camphor is a terpenoid, better known as a moth repellent. "Benzoxycamphor" doesn't really make sense as a chemical name, but it could be a (badly named) derivative of camphor.Pikiwedian 07:21, 5 September 2006 (UTC)[reply]

Dense material

Hi. I'm looking for an element/alloy as dense as possible, as cheap as possible and as malleable as possible (in order of descending importance) and without any other undesirable property, such as toxicity. I read the articles osmium and iridium but, while their density is excellent for my purpose, they are cost-prohibitive and, to make matters worse, osmium oxide is said to be very toxic. Any ideas? Thank you very much.

EDIT: OK. The idea is to have weights in the ankles to increase leg strength while running, but they are normally made of a substance which causes the weights be too bulky and uncomfortable, and at the same time, they weigh too little.

If you tell us what you want to do with it, someone may be able to suggest the best thing. --liquidGhoul 11:09, 30 August 2006 (UTC)[reply]

Lead would probably be the normal choice for this, although it is toxic if ingested. Just encase the lead in plastic to solve that issue. StuRat 11:22, 30 August 2006 (UTC)[reply]

Depleted uranium? 8-). Otherwise brown lead.--Light current 11:37, 30 August 2006 (UTC)[reply]

Maybe a better idea would be to put chewing gum on the soles of your shoes. THat would slow you down! OR.. you could try running thro water-- thats hard! OR long grass etc!--Light current 12:03, 30 August 2006 (UTC)[reply]

I second the vote for lead. You could encase it in rubber very easily with that stuff that you can get at hardware stores for dipping the handles of tools into to give them a rubber grip. Dismas|^(talk) 13:55, 30 August 2006 (UTC)[reply]

Not helping, but I wouldn't be surprised if (or I'm pretty sure that) those ankle weights are usually filled with lead in the first place. freshofftheufo ΓΛĿЌ 14:13, 30 August 2006 (UTC)[reply]

You didn't ask for this but I'm giving it to you anyway. Ankle weights are not the best way to gain leg strength; in fact, for the amount of torque they put on your knees, it's really really really not worth it. Just go to the gym. Weight training is a very good compliment to aerobic exercise. Anchoress 15:45, 30 August 2006 (UTC)[reply]

Or wading thro water. OR the simplest of them all-- cycling--Light current 16:11, 30 August 2006 (UTC)[reply]

Your best bet to accomplish what you are looking for is running up slopes or setting a high incline angle on a treadmill.--JLdesAlpins 16:56, 30 August 2006 (UTC)[reply]

Or cycling uphill.--Light current 16:59, 30 August 2006 (UTC)[reply]

On a treadmill, perhaps. In any case, I can see you're into cycling. :-) —Bromskloss 19:37, 30 August 2006 (UTC)[reply]

For some reason, no one's mentioned this yet (enough (Anchoress)). If the masses are more than 1.5kg per leg, you risk serious ligament damage to the knees. You might think that a leg weighs a good 20kg or so, so what difference is 2kg gonna make? But, a leg's weight is distributed with most of it at the top (thigh), so adding 2kg to the feet is very unbalanced. The problem arises in that the knee is designed to take mainly compressive loads, and the artificial mass you've added is pulling down on the knee joint, not the way it's supposed to. Just a heads up. ≈Eh-Steve 18:06, 30 August 2006 (UTC)

Thank you very much for all your responses.

Algae

Can algae utilize amino acids from their culture medium? I mean specifically can they use the amino acid directly to build protein, without first breaking the amino acid down, the way an animal can. (I am specifically interested in the species schizochytrium limacinum)ike9898 14:12, 30 August 2006 (UTC)[reply]

Algae are not consumers, and hence have no mechanism for which to absorb the amino acid into their cell. --liquidGhoul 14:21, 30 August 2006 (UTC)[reply]

Are you sure? Some artifical algae culture media includes peptone. ike9898 14:28, 30 August 2006 (UTC)[reply]

I see the problem here, Schizochytrium limacinum is a protist which either acts as a decomposer, or a parasite to algae. Check out Labyrinthulomycetes, it has Schizochytrium in the list of genera. --liquidGhoul 14:55, 30 August 2006 (UTC)[reply]

Body fat and menstruation

What is the minimum body fat percentage needed for a woman to menstruate? I looked in body fat percentage and menstrual cycle and even amenorrhoea, but couldn't find that particular piece of information. CameoAppearance 15:22, 30 August 2006 (UTC)[reply]

This link here references a 1981 JAMA article showing that less than 17% body fat is associated with amenorrhea. It sounds like there is more to the story than just that (ie genetic factors) InvictaHOG 15:51, 30 August 2006 (UTC)[reply]

I don't know if there is an absolute cut-off for minimum body fat in order for menstruation to occur. For instance, exercise-induced amenorrhea may have something to do with the loss of diurnal variation in leptin as a woman loses weight, and also with relative caloric deficiency due to inadequate nutritional intake for the amount of energy expended. Rather than body fat percentage, studies often use body mass index. See also this study - Cybergoth 16:01, 30 August 2006 (UTC)[reply]

Some quotes gleaned from various sources:

"Some become amenorrheia at 18 percent, others at 16 or 14 percent," Lohman [director of the body-composition lab at the University of Arizona College of Medicine Department of Physiology in Tucson] says.
Why, given a group of women with similar exercise programs and low percentages of body fat, do some experience menstrual problems and others do not? The answer usually relates to nutrition. Women with amenorrhea may be striving to maintain a weight lower than appropriate for their genetics. When the cost of achieving this desired leanness is inadequate nutrition, menstruation will cease.
Amenorrhea is the clinical term for cessation of menstrual periods with possible related loss of ovulation. This is generally seen in women who train very heavily and/or have bodyfat below 12-15%; [...] However, research has demonstrated that amenorrhea is not caused by low bodyfat per se. Rather, it appears to be triggered by a long-term negative energy balance, which can result in a low bodyfat.
There seem to be many factors which contribute to menstrual disturbance in female athletes. [...] In the early 70s two scientists suggested that a body fat percentage of 17 percent is required for menstruation to begin and 22 percent is needed for menstruation to be maintained. [...] However, this is not the complete answer. Some ballet dancers and swimmers who develop menstrual irregularities when training become more regular when they are not training, even though their body weight does not change. Some amenorrhoeic runners are of normal weight and other studies have found no difference in height, weight or percentage body fat between amenorrhoeic and menstrually-regular runners. [...] There does seem to be a direct relationship between the training load and the degree of menstrual irregularity, at least in runners. One study found a direct relationship between distance run per week and the incidence of menstrual irregularities, although an exact threshold above which menstrual irregularities start to occur has not been found.

It appears that there is no easy answer. --Lambiam ^Talk 16:01, 30 August 2006 (UTC)[reply]

tetrachlorodibenzo-para-dioxin (TCDD) and Thyroid disease

The EPA and the National Academy of Science do recognize that TCDD has some effect on endocrine receptors in humans. Just how and at what dose seems still to be a mystery. Looking for all the information I can get on this subject.

Looks like you've stumped Wikipedia! Rentwa 16:55, 1 September 2006 (UTC)[reply]

Mattresses

What benefits would evolving in the shape and density of a mattress have, and how might one evolve in such a way given survival of the fittest and all that? This is not a homework question. freshofftheufo ΓΛĿЌ 15:41, 30 August 2006 (UTC)[reply]

Is this a The Hitchhiker's Guide to the Galaxy related question? I would assume that it would greatly depend on the environment the creature lives in, and the way that the surrounding organisms have evolved. There are probably countless ways that mattresses could evolve, including artificial selection. -- Consumed Crustacean (talk) 15:52, 30 August 2006 (UTC)[reply]

Can you clarify the question? Is this a question about the evolution of mattresses qua shape and density, or about the evolution of some species, such as Homo sapiens, into mattress-shaped lifeforms? --Lambiam ^Talk

I don't see why it would be any more unreasonable to expect homo sapiens to become mattresses. It might even be easier that way, because, as you could probably guess, these mattresses can talk. freshofftheufo ΓΛĿЌ 17:14, 30 August 2006 (UTC)[reply]

Im gonna have to sleep on that one!--Light current 16:13, 30 August 2006 (UTC)[reply]

groan* --Froth 14:36, 31 August 2006 (UTC)[reply]

Stackability would ensure efficient sleeping, transport, and sexual arrangements, sound absorbency would mean a quieter environment, crashes and jumping from a great height would rarely be fatal,...--Shantavira 17:44, 30 August 2006 (UTC)[reply]

Yes! Stackability, now that would be useful. I can imagine scenarios where a creature would give up their ability to walk instead gaining the ability to bound short distances, most of them being in extremely docile environments where food supply is always guaranteed. freshofftheufo ΓΛĿЌ 05:58, 31 August 2006 (UTC)::[reply]

Over active thyroid

Is it possible to:

Be thin as a rake (ie BMI = 18)
Not sleep well
Have very fine hair (someties falling)
Have Very smooth skin
Always be 'on the go'
Have limited attention span (scatter brained)

and not have an over active thyroid?--Light current 17:21, 30 August 2006 (UTC)[reply]

Since you're using an AND logical construction, all of the conditions must evaluate to YES in order for the function to also result in YES. Since it is not possible to be as thin as a rake (even the skinniest humans easily eclipse common rakes), I can therefore safetly conclude that the answer to your question is no. freshofftheufo ΓΛĿЌ 17:34, 30 August 2006 (UTC)[reply]

OTOH, from the principle of explosion, anything follows from a contradiction. If a person is thin as a rake, we have a contradiction, because you showed that they're not. So, anything follows. Even thyroids on steroids. —Bromskloss 19:33, 30 August 2006 (UTC)[reply]

Depends on thet size of your rake dont it? 8-) OK If you have all the above conditions, can you stil NOT have an over active thyroid?--Light current 18:13, 30 August 2006 (UTC)[reply]

Did you try to create that userbox "This user wants to be convinced that (s)he has an over active thyroid", with a nice picture of one ? -- DLL ^{.. T} 18:41, 30 August 2006 (UTC)[reply]

I know not of what you speak, dear sir!--Light current 18:43, 30 August 2006 (UTC)[reply]

Add in the other common symptoms like high appetite, diarrhea, headaches, and high libido and you are closer to describing a textbook case of hyperthyroidism, not that you should ever be using wikipedia to fetch medical advice... To more directly answer your question, see Amphetamine or UBS Guy for a possible alternate explanation --Jmeden2000 20:41, 30 August 2006 (UTC)[reply]

Ah well, she aint got diarrea, headaches, and is as cold as a fish! How now? Should I be telling her to go to the doctor TITQ--Light current 20:46, 30 August 2006 (UTC) Oh yeah I forgot to say she has good appetite but somtimes misses meals cos shes so busy running round.--Light current 21:41, 30 August 2006 (UTC)[reply]

If you think the factors are abnormal then a visit to the doctor would be in order. Consider that you may be projecting hypochondria, not that I am qualified to make that diagnosis (perhaps i am a vicarious psychoanalyst but again this is no place for medical advice). --Jmeden2000 21:00, 30 August 2006 (UTC)[reply]

It is certainly possible to have those symptoms and not have hyperthyroidism. However, those symptoms should certainly prompt thyroid testing, as they are commonly associated with an overactive thyroid. InvictaHOG 21:05, 30 August 2006 (UTC)[reply]

What do I say to try to get her to go? Shes quite strong willed and may resent me suggesting she is not completely fit. She says shes always been v thin and her brother is the same. Could he have it too?--Light current 21:13, 30 August 2006 (UTC)[reply]

If she doesn't want to listen to you, she won't. Just give it your best try. If she's going to the doctor anyway, it's just a simple blood test. InvictaHOG 01:07, 31 August 2006 (UTC)[reply]

THanks to all for the replies!--Light current 01:11, 31 August 2006 (UTC)[reply]

Intelligence

Does editing WP make you more intelligent? If so, how long does it take to work/ 8-?--Light current 18:55, 30 August 2006 (UTC)[reply]

Yes, of course. Within a month of editing at Wikipedia you will have amassed a lifetime of knowledge about exploding whales, masturbating pigeons and how to suitly emphazi a question. There are plans to release a pill which will contain all this information and transmit it into the brain of the taker, which will render all your gains obsolete soon though. —D a niel (‽) 18:47, 30 August 2006 (UTC)[reply]

WP won't be of much help if you can't even remember to sign your posts. ;-) --hydnjo talk 18:50, 30 August 2006 (UTC)[reply]

Sorry--Light current 18:55, 30 August 2006 (UTC)[reply]

See, you're getting smarter already. 9-) --hydnjo talk 19:17, 30 August 2006 (UTC)[reply]

Why is your writing so small?--Light current 19:23, 30 August 2006 (UTC)[reply]

Because I'm writing quietly. --hydnjo talk 19:34, 30 August 2006 (UTC)[reply]

Why are you writing quitely?--Light current 19:36, 30 August 2006 (UTC)[reply]

So as to not call much attention to some of my posts, but It doesn't always work. --hydnjo talk 19:43, 30 August 2006 (UTC)[reply]

WRITING BIGLY WORKS BETTER TO DIVERT ATTENTION AWAY FROM YOURSELF. — [Mac Davis] (talk) (Desk|Help me improve)

Umm, more like a device to give the impression of a footnote or a parenthetical. --hydnjo talk 20:02, 30 August 2006 (UTC)[reply]

Er.. yes?--Light current 20:30, 30 August 2006 (UTC)[reply]
...er..umm... yes, excactly. --hydnjo talk 21:14, 30 August 2006 (UTC)[reply]

Not to be a pain, but...please don't use the reference desk as a chat room. How about using your talk page? ike9898 21:23, 30 August 2006 (UTC)[reply]

Im not using it as a chat room. We may be digressing somewhat-- thats all.--Light current 21:26, 30 August 2006 (UTC)[reply]
And I certainly have no intention of sharing a room with Lc. --hydnjo talk 21:58, 30 August 2006 (UTC) [reply]

In all seriousness... using your brain in any intellectual pursuit, from doing logic puzzles to writing research papers, improves your thinking ability. Editing Wikipedia surely qualifies as the latter ... or at least it should, if you're doing it right. --Ginkgo100 ^{talk · e@} 20:33, 30 August 2006 (UTC)[reply]

Intelligence and knowledge are two different things, but yes doing stuff that challenges your brain like reading and editing Wikipedia is probably going to be benefitial for your IQ. - 131.211.210.11 07:50, 31 August 2006 (UTC)[reply]

My typing and grammar have gotten much better since I started Wikipedia (especially my typing, I couldn't touch type before and now I am quite proficient!). --liquidGhoul 12:32, 31 August 2006 (UTC)[reply]

creatine article

in the creatine article there is a statement that there are vegetarian sources of creatine. I have not been able to find out what those sources are so i would much appreciate further information on the subject.

205.56.129.194 19:28, 30 August 2006 (UTC)Smith[reply]

Vegetarian creatine can be obtained via chemical synthesis using plant-derived amino acids.--Light current 19:35, 30 August 2006 (UTC)[reply]

Asking a subject reference question

Aha! I think this is the feature I was looking for. Thank you!

...Do you have a question? --Ginkgo100 ^{talk · e@} 20:31, 30 August 2006 (UTC)[reply]

He/she was just seeing if they knew how to ask a question if they needed too. He/she thanked as for the future service we may do to him. We are, after all, "in the service." — [Mac Davis] (talk) (Desk|Help me improve)

You're welcome (to what I'm not sure, though). DirkvdM 08:44, 31 August 2006 (UTC)[reply]

Iran and Nuclear Power

Why does Iran want to build nuclear power plants when they have such a large oil reserv?165.139.186.7 20:03, 30 August 2006 (UTC)[reply]

I wonder!--Light current 20:32, 30 August 2006 (UTC)[reply]

For lots of information see Iranian nuclear program; their rationale is treated at Iranian nuclear program#The Iranian Point of View. Melchoir 21:10, 30 August 2006 (UTC)[reply]

They're afraid of global warming, which, disputably, will cause a drastic rise in the ~~seagull~~ bagel population. In the 147th passage of the Qu'ran, it states "Jihad shall be against the non-Islamic, and bagels." It is really a three-fold problem for them. The educated Islamofascist know that global warming will simultaneously cause a spike in bagel populations, Kill All Humans, and, because humans are much more productive when temperatures are hotter, the fucking infadels will have better technology. — [Mac Davis] (talk) (Desk|Help me improve)

why does the US want to build nuclear power plants, when they have such large oil reserves (not to mention bagels). Xcomradex 21:58, 30 August 2006 (UTC)[reply]

Both parts of your statement are completely wrong; the US does not have enough current oil production to meet it's own needs, an it's not currently building nuclear power plants (although perhaps it should be). StuRat 03:21, 31 August 2006 (UTC)[reply]

So they have more enriched uranium and plutonium than Iran (and prob everyone else put together) of course. 8-)--Light current 22:02, 30 August 2006 (UTC)[reply]

It's just a cover story so Iran can build nuclear weapons, even the normally gullible Europeans can see this. StuRat 22:05, 30 August 2006 (UTC)[reply]

Really? I would never have guessed that! 8-)--Light current 22:06, 30 August 2006 (UTC)[reply]

Probably, yes. But this is the science reference desk, and that is not a falsifiable hypothesis. Melchoir 22:18, 30 August 2006 (UTC)[reply]

There's a lot of people who think like StuRat (and on this rare occasion I do happen to at least partially agree with him) but the Iranians argue that a) they want to make sure their petroleum reserves last as long as possible, and b) those petroleum reserves are more valuable being sold than generating power domestically. See nuclear program of Iran. --Robert Merkel 22:25, 30 August 2006 (UTC)[reply]

After Pakistan said they weren't working on nuclear weapons, then completed one, then North Korea did the same, anyone who believes that Iran, a country which publicly calls for the destruction of Israel and publicly supports a terrorist organization trying to do just that (Hezbollah), just wants "peaceful" nuclear energy, is truly naive. StuRat 23:10, 30 August 2006 (UTC)[reply]

Also, try Iran's civilian nuclear program. Melchoir 22:35, 30 August 2006 (UTC)[reply]

I think that Iran's leaders are playing two games at once. One is the development of what is currently a nuclear program of dual-use technology—everything in their program ostesibly has a peaceful purpose, though all of it could also be diverted for a weapons program as well. This gives them a little room to claim that they are having their rights trampled on—according to the NPT, peaceful nuclear programs are allowed, though with some qualifications. The second game is related to the first; they get to be a leading voice in the region confronting the United States, claiming scientific progress, and using the entire incident as an opportunity to point out the double standard that the U.S. has towards Israel's nuclear weapons program. The Iranians also are fond of saying something very strong—i.e. that Israel should be wiped off the map—and then backing down from it with a more mild explanation—i.e. that they were only talking about it in defensive terms, and that they were just warning Israel not to attack them unprovoked. It puts them in an advantageous regional position, and I don't think its a coincidence that their hardliner president dresses in Western clothes and looks more like a Western politician than he does a Shiite cleric.

As for the oil reserves—I'm pretty sure even the most optimistic estimates point to a falling off of Middle Eastern oil reserves within the next two decades or so, which will put Iran and everyone else over there up a creek if they don't have fallback industries and energy production.

Are they making a bomb? Probably not at the moment, not as a full program anyway. They're hedging their bets for one though, trying to get just enough technology that they'll be able to work one up over time (the same way Pakistan did theirs, which took decades to make because they were content with doing it slowly). At the moment they are pursuing so many alternative routes—uranium, plutonium, etc.—that they could drop one of them from international pressure and still be able to pick up the slack in another area.

Most analysts don't think Iran could develop a bomb within the next decade, though. The real regional danger of Iran getting a bomb is less that they would use it against Israel, but would rather use it as a check against Israel using their own bomb against them, and then hope to beat Israel at conventional warfare, IMO. (My personal biggest fear at the moment is that Israel will, one way or another, get involved in a war with Iran as they are currently with Lebanon, and then drag the United States/United Nations in with it.) --Fastfission 23:37, 30 August 2006 (UTC)[reply]

It's true, Iran has an enormous army with an enormous number of personnel and likely a pretty hefty cache of land artillery. Yet its air force and navy are practically non-existant. With the possible exception of some long-range conventional missiles, how could Iran possibly conduct any sort of conventional warfare against Israel? How would they even get there? Would several hundred thousand Iranian troops be zipping through a couple of thousand miles of desert, through US occuppied Iraq and then Jordan on dune buggies? Loomis 01:26, 1 September 2006 (UTC)[reply]

Any claim Iran makes to only want a peaceful nuclear program was shown to be false by their rejection of Russia's offer to provide nuclear fuel and get the spent fuel back. This would provide Iran with all the nuclear power they wanted, but deny them the possibility of enriching the fuel further for use in nuclear weapons. Therefore, Iran rejected the offer. StuRat 23:45, 30 August 2006 (UTC)[reply]

Yes, because Iran's experience with OPEC has taught it that building an energy infrastructure around a foreign source of fuel is such a good idea. Melchoir 23:57, 30 August 2006 (UTC)[reply]

I don't think a single rejection of a plan can be used as a convincing case, especially when it is a plan that forces them to basically be at the diplomatic mercy of another country. (And it is not like Russia has not used denial of resources before as a way to throw around weight, i.e. by denying oil to Ukraine and things like that.) If I were a president of a country like Iran, I wouldn't be too eager to have my nuclear program be completely at the mercy of the Russians. I think it is more convincing that Iran has continually sought dual-use technology even when there have been options otherwise, and that they have so far been resistant on safeguards. --Fastfission 00:32, 31 August 2006 (UTC)[reply]

Unlike OPEC's oil, even if Russia stopped supplying nuclear fuel, it would be years before Iran's current nuclear fuel supply would be spent, giving them plenty of time to switch to another supplier or back to oil. Therefore, any Russian threats to cut their supply would be highly ineffective. StuRat 03:18, 31 August 2006 (UTC)[reply]

the US's opinion back during the days of the Shah was iran would need five nuclear power plants by 1994 (number from memory), and they even helped arrange a consortium with germany and france to build said powerplants. yet fast forward a few years and look what happens. Xcomradex 02:07, 31 August 2006 (UTC)[reply]

Ahh, but the Shah was America's friend! (Not the peoples friend)--Light current 03:13, 31 August 2006 (UTC)[reply]

One should never put all of one's eggs in one basket. As was indicated before one can ask a similar question of many other countries (and also why they would need or have more right to nuclear weapons, for that matter). The Netherlands has the biggest gas bubble in the world. So what do we need nuclear plants for? A better question might be why they don't focus on solar energy, considering their climatic situation. Or do they? I don't know. DirkvdM 08:58, 31 August 2006 (UTC)[reply]

To offer a Canadian perspective, just as Iran's oil reserves may some day run out, necessitating the need for nuclear power, up here we fear that global warming will eventually eliminate all the snow from falling, thus destroying an extremely important aspect of our tourism industry, alpine skiing. Yes it's true, we fear that one day Canada will face a shortage of snow. With that in mind we're currently working on a snow making machine, using technology which, completely coincidentally, can be used to create a weapon that can destroy the evil American regime which should be wiped off the face of the map. Not to worry though, global warming is real, and we truly believe that such a machine will be necessary once all of Canada's snow has melted away and no more will continue to fall. Oh, and by the way, death to America. Peace y'all! Loomis 09:03, 31 August 2006 (UTC)[reply]

That's why nobody ever asks for a Canadian's perspective. freshofftheufo ΓΛĿЌ 12:14, 31 August 2006 (UTC)[reply]

Ouch! Why's that? Because nobody can handle the truth? Loomis 00:38, 1 September 2006 (UTC)[reply]

I agree that the question should be "with all the possible forms of energy available to Iran, why do they insist on the one form that also allows them to develop nuclear weapons, and reject any method that would allow them to develop peaceful nuclear power, but prevent them from developing nuclear weapons ?" Hmmm ... I just can't figure it out. StuRat 13:03, 31 August 2006 (UTC)[reply]

I'm just as confused as you are Stu. What do you suggest should be done? I say we force Iran to allow UN observers complete access to every nuclear power plant in Iran. That way, we'll all be safe in the knowledge that Iran won't be building nuclear weapons under all of our noses. That way, we'll be safe in the knowledge that Iran will only be building nuclear weapons openly and honestly under strict UN supervision. Loomis 01:06, 1 September 2006 (UTC)[reply]

The only possible solution I see is a military action, most likely taken by Israel, with US covert support. The UN will first put some weak, thoroughly useless sanctions on Iran, and will violate even those. This will have absolutely no effect on Iran. Then, when it is clear that Iran has nearly completed it's nuclear weapons, the only option left will be military action. I suspect the sites will be bombed with "bunker-buster" bombs (possibly low yield, tunneling nukes). It's too bad we don't have an effective UN that could actually take the actions necessary to get Iran to stop peacefully. That would take total sanctions on Iran, sealing all of the borders. The weakness of the UN makes war inevitable. StuRat 10:47, 1 September 2006 (UTC)[reply]

If all countries with nuclear plants would allow that (do any now?) and Iran would still not agree to it, then they would look pretty suspicious. It's mind boggling how often people find it perfectly normal to do unto others what they would never allow those others to do unto themselves. DirkvdM 09:04, 1 September 2006 (UTC)[reply]

Under your theory, since police have guns, we must provide all criminals with guns, as well, so we treat everybody equally. I would expect the US would agree to UN inspectors of their nuclear reactors, if that would get Iran to do so. However, inspecting US nuclear plants would be a complete waste of time, as the US already has more nuclear weapons than it knows what to do with. StuRat 10:33, 1 September 2006 (UTC)[reply]

I skipped that last bit to avoid complicating matters too much, but thank you fro bringing it up. You ma now attempt an answer to that hypocricy as well. :)

The police (and the army if needs be, but that never comes up domestically) should have a "monopoly on violence" as we say in Dutch. Translate this to international affairs. Who is to be the police? One specific country or a group of coutries or a joint effort of all countries in the world? Suppose the separate states in the US were different countries (not too far from the truth). What if California, in alliance with the rest of the West Coast would claim a right to all nuclear facilities and weapons and would invade other states if they had any plans of developing their own technology (or economic system, or whatever)? DirkvdM 13:04, 1 September 2006 (UTC)[reply]

OK, I can answer your silly scenario. Let's now say that Pennsylvania is dedicated to the total destruction of Virginia, says so publicly, and supports various terrorist organizations that launch missiles into Virginia, send suicide bombers into Virginia, and stockpile weapons in West Virginia, on the border with Virginia. Let's also say their terrorist organization is destabilizing West Virginia and causing destruction to it's infrastructure by Virginians trying to defend themselves from these constant attacks. Now Pennsylvania is claiming they need nuclear power, despite huge oil and gas reserves. They have rejected any attempt to monitor their nuclear plants to be sure they aren't building nuclear weapons and have been caught numerous times cheating on the nuclear nonproliferation treaty. Now, under these circumstances, absolutely, those states with nuclear weapons should all work together to prevent Pennsylvania from ever getting them. Hopefully, responsible states without nuclear weapons will also join in. If nothing else works, Pennsylvania should then be attacked, before it gets nuclear weapons. StuRat 06:12, 2 September 2006 (UTC)[reply]

But the US already have nuclear weapons, so are you saying we're too late with the invasion? Or weren't you talking about the US? DirkvdM 09:03, 2 September 2006 (UTC)[reply]

The word is "has". If there were aliens who could keep everyone from getting nuclear weapons, including the US, then that would be a good thing. However, as none seem willing to help us out that way, the next best thing is for as few countries as possible to have them; ideally only the "good" countries (which won't just use them to kill off or enslave everyone else in the world, as the Nazis, imperial Japanese, or Soviets would have, had each been the only country with nukes). StuRat 01:23, 3 September 2006 (UTC)[reply]

I don't see why the whole thing has to be turned pro or anti-US. Putting aside the US for now, there are still quite a few countries around the world that are stable and (relatively!) sane enough that no one worries whether or not they possess nuclear capabilities. Check out the list of countries with nuclear weapons. The Brits have the bomb, and that doesn't concern me one bit. The French...well despite being French and all, I'm not at all worried about their nukes either. As for Russia and China, though they may be misfit states, they still seem to be sane and practical enough to me (and have the track record to prove it) that they have no intention of launching an unprovoked nuclear strike on anyone. As for India and Pakistan, their main beef is with each other. Both being secular, the old Mutual Assured Destruction (MAD) principle would seem to take nuclear war out of the picture. And of course there's the Israelis, love'em or hate'em, whatever nukes they may have might just as well be harmless drones, built entirely for deterrent effect. I just can't see Israel ever using them, ever, even as a second strike. It just doesn't jive with the Israeli psyche.

The article also points out that countries like Canada, the Netherelands, Australia etc...(I picked those totally at random :) have all the technology necessary to build a bomb in a matter of weeks, but that doesn't concern me either. These countries are, (at least for the most part!) sane and pacifist, and see no use in possessing nuclear weapons, and rightly so, nobody seems at all concerned with whatever technological capabilities they possess.

But then you come across countries like Iran and North Korea. I'll leave North Korea aside for now. In the case of Iran though, the old MAD principle actually doesn't seem to apply. Even the Soviets weren't insane enough to launch a first strike, because to do so would risk an equally devastating reply from the US. Iran, on the other hand, is a different story. With its shahidist mentality, MAD would actually seem to have no application. "Nuke the Zionists and who cares if they nuke us back? We'll all go to heaven and they'll all go to hell". Now THAT scares the shit out of me. People speak of "double standards"...well I'd say there's a pretty solid logical basis for these "double standards". Loomis 14:29, 1 September 2006 (UTC)[reply]

Well said. Just as sane, responsible gun owners are OK, but giving guns to insane criminals is very bad, so would giving nukes to Iran be a very bad thing. For example, I would not be opposed to Japan getting nuclear weapons, as I only see them being used to prevent an attack by North Korea. StuRat 05:59, 2 September 2006 (UTC)[reply]

Most distant spacecraft visible from Earth

I have two questions:

1. What is the most distant spacecraft visible to telescopes on Earth? 2. What is the brightest spacecraft not in orbit around the Earth, and how bright is it?

--Bowlhover 21:41, 30 August 2006 (UTC)[reply]

The brightest not-in-orbit spacecraft would probably be something very close, maybe New Horizons, launched in January and by my calculations about 7 million miles away. The Wilkinson Microwave Anisotropy Probe is technically not in orbit around the Earth (it orbits the Sun-Earth L₂ point about 1.2 million miles away). I'm not certain if it ever comes out of the earth's umbra, but if it does, it's probably pretty dang bright. (Relatively speaking) -- Plutortalk contribs 22:27, 30 August 2006 (UTC)[reply]

I thought about mentioning WMAP, and am likewise unsure of the umbra. On the other hand, SOHO is at the L1 point, and so is certainly in plenty of sunlight, but is also completely obscured by solar glare. If you don't like those, the current leader is likely SMART-1 orbiting the Moon, though it's about to crash. — Lomn | Talk 22:39, 30 August 2006 (UTC)[reply]

Well, Earth has an angular diameter of 0.24 degrees to the WMAP. The Sun has a diameter of 0.53 degrees, so our planet can't block more than 21% of the Sun's light. In other words, the WMAP is in sunlight. Anyone know how bright it is? --Bowlhover 05:21, 31 August 2006 (UTC)[reply]

Why can't we feel the mantle heat through the crust of the earth?

I have done a lot of research into plate tectonics and the geology of the earth on Wikipedia. I have learned a LOT, but I can't seem to find an answer to the following (basic) question anywhere:

If the mantle inside the earth is molten rock at 1200 to 2200 degrees (F), why doesn't any of that heat pass through the earth's crust (by convection) and reach the surface?

If there is THAT MUCH heat energy inside the earth, I would think that we should be able to experience at least SOME of it on the surface.

Thanks in advance! :-)

Tim Barber (Harrisburg, PA)

We do! Ever heard of hot springs, volcanoes etc. THe miles and miles of rock forming the earths crust are a good insulator thankfully--Light current 22:09, 30 August 2006 (UTC)[reply]

Yes, rock is a good insulator, so any heat that the mantle delivers to the crust will be radiated away into space. It's like putting a block of wood on a stove--the wood (except for the part that touches the stove) won't feel hot. --Bowlhover 22:15, 30 August 2006 (UTC)[reply]

Also, the temp a few hundred feet underground is largely heat rising from the mantle. Only near the surface does heat from the Sun become dominant. StuRat 22:30, 30 August 2006 (UTC)[reply]

Yes for instance in some caves I recently visited, the temp is constant 12 deg celsius--Light current 22:34, 30 August 2006 (UTC)[reply]

We do feel it! If it weren't for the heat coming out through the crust from the interior of the Earth, the Earth surface where we live would be very much colder than it is. The heat is produced (mostly) by radioactive decay (and, by the way, goes through the crust by conduction, not convection). --mglg_(talk) 22:58, 31 August 2006 (UTC)[reply]

Correct, the heat gets to the crust by convection, then goes thru the crust by conduction (excluding geysers and lava spewing out of volcanoes). StuRat 10:28, 1 September 2006 (UTC)[reply]

I need to find critics to the socialist ideas.

thanks

Criticisms of socialism you say?--Light current 22:32, 30 August 2006 (UTC)[reply]

Do you mean finding the people themselves? —AySz88 \^-^ 00:24, 31 August 2006 (UTC)[reply]

Not that you have any preconceptions of course. :) Ah, I get it, socialism makes so much sense that you can only think of pros and need others to make up the cons for you. :) DirkvdM 09:07, 1 September 2006 (UTC)[reply]

Question on the derivative market

Question on the derivative market and particularly on the process with several volatilities:

I would like to know if any process with more than one volatility for an underlying asset exist.

Nicolas

Economics homework? Its so easy with WP--Light current 00:27, 31 August 2006 (UTC)[reply]

Please do not double post. --Lambiam ^Talk 02:44, 31 August 2006 (UTC)[reply]

Perpetual Motion

Is there anyone i can contact who is an expert in perpetual motion?

Nick Muller

Perpetual motion is a good read with some interesting external links. --hydnjo talk 23:57, 30 August 2006 (UTC)[reply]

If you want to take them at their word, the guys as Steorn would have you believe they are the best in the business. Rockpocket 05:19, 31 August 2006 (UTC)[reply]

But, if you read the long discussion below, they are mostly likely wrong. — QuantumEleven 07:41, 1 September 2006 (UTC)[reply]

Some call me an expert in my field, unfortunately though I stop every night to sleep. So I suppose I wouldn't qualify as an expert in perpetual motion. Loomis 04:29, 2 September 2006 (UTC)[reply]

August 31

Beef jerky

Can beef jerky, and jerky in general, be reconstituted, perhaps using broth? I'm sure it would be terrible, but is it even possible? Bhumiya (said/done) 01:48, 31 August 2006 (UTC)[reply]

I believe an MRE kit contains dehydrated meat to be soaked in water, with the idea being that the finished product will resemble actual meat. StuRat 02:06, 31 August 2006 (UTC)[reply]

Since its only dried meat, I dont see why it couldnt be reconstituted by heating in a pan (or uwave) with water. Yummy--Light current 02:07, 31 August 2006 (UTC)[reply]

Most dehydrated things can't be rehydrated to get the original back. A raisin soaked in water, for example, doesn't give you a grape, it give you a soggy raisin. StuRat 02:14, 31 August 2006 (UTC)[reply]

Thats just sour grapes on your part! 8-)--Light current 02:20, 31 August 2006 (UTC)[reply]

And if soggy raisins get you mad, then they would be The Grapes of Wrath. :-) StuRat 02:29, 31 August 2006 (UTC)[reply]

Actually I thought raisins were made from special sorts of grapes but the current thinking is that currants raisins and sultanas are all in fact dried grapes. I see no reason to doubt that.--Light current 02:36, 31 August 2006 (UTC)[reply]

Maybe you can reconstitute it, but I do not think you will get a properly functioning cow back. --Lambiam ^Talk 02:49, 31 August 2006 (UTC)[reply]

Has any one noticed that the indentation is now rather pretty? shame I have to spoil it!--Light current 02:56, 31 August 2006 (UTC)[reply]

Not really, we can still go back and forth to keep up the pretty little indentation thing. As for the question, you know when people do weird stuff on tv and tell you "Please, by all means, DO NOT try this at home"? Well I don't think that would apply here. I can't see much harm resulting if you boiled a piece of beef jerkey and waited to see what happened. Keep us updated, the scientific community is relying on you for this one. Loomis 08:42, 31 August 2006 (UTC)[reply]

Yes I suggest the questioner try it at home!--Light current 11:04, 31 August 2006 (UTC)[reply]

You can reconstitute food to some degree. The water has gone from the cells and they won't function like perfect sponges, but you can get some water in there. Reconstituted jerky is usually mentioned as good for stews. I doubt you get a good filet mignon out of dried meat. Google for rehydrate jerky or reconstitute jerky. Weregerbil 11:33, 31 August 2006 (UTC)[reply]

physics andtehnology

59.93.32.70 02:28, 31 August 2006 (UTC)anees application of physics in other science disciplines ,or how physics theories applied in different science subjecs[reply]

ronlem unnerstanig qestiom ,please suitly emphazi Lambiam ^Talk 02:51, 31 August 2006 (UTC)[reply]

I can work out most of the words, but what the hell is 'ronlem' supposed to be? Hang on I just saw it!--Light current 03:15, 31 August 2006 (UTC)[reply]

Body hair

Why do men have more body hair than women. Do women not feel the cold as much?--Light current 03:10, 31 August 2006 (UTC)[reply]

To differentiate the genders. (We have to make the trannies work a little bit, don't we ?) :-) StuRat 03:32, 31 August 2006 (UTC)[reply]

A trannie is a transistor radio! It was when I was young.--Light current 03:33, 31 August 2006 (UTC)[reply]

Well, I wouldn't suggest you go around telling people you enjoy fiddling with the knobs on your favorite trannies. :-) StuRat 03:37, 31 August 2006 (UTC)[reply]

Can I have an anthropological answer please?--Light current 03:33, 31 August 2006 (UTC)[reply]

I gave you one. It's so men and women can tell each other apart, which is rather critical to reproduction and survival of the species. StuRat 03:46, 31 August 2006 (UTC)[reply]

For sexual dimorphism. I restate the first answer. — [Mac Davis] (talk) (Desk|Help me improve)

What about monkeys? They can tell the diff, and theyre all hairy!--Light current 03:47, 31 August 2006 (UTC)[reply]

I suspect that the general reduction of hair in modern humans came as a result of clothing, making the thermal properties of hair optional, and thus a candidate for sexual dimorphism. Body hair isn't the only way we have to differentiate the genders, but the more obvious the genders are, the better for the species. StuRat 03:52, 31 August 2006 (UTC)[reply]

Possible. I would like more views please. BTW does that mean you couldnt recognise a woman if she was hairy all over? 8-) --Light current 04:03, 31 August 2006 (UTC)[reply]

The actual functional purpose of human body hair is no longer directly relevent as - most of us at least - wear clothes. Dimorphic body hair is a secondary sexual characteristic, that is, it is a result of the genetic/biochemical differences between men and woman. Specifically, increased levels of androgens in males promote the transformation of vellus hair to terminal hair in certain parts of the body. The reason some parts grow more than others is probably due to the androgen sensitivity in the local follicles. Rockpocket 05:17, 31 August 2006 (UTC)[reply]

Hey Light current we recognized you didn't we! Lemon martini 08:00, 31 August 2006 (UTC)[reply]

As what, may I ask?--Light current 11:44, 31 August 2006 (UTC)[reply]

Conjecturing that we have less body hair because of clothing is sort of backwards to me. We've been less-haired for quite some time, and it's more likely that clothing came about as a result to warm ourselves in contexts where thick body hair could've worked. Considering that modern humans evolved in Africa and there are other less-haired mammals (like elephants) in Africa, I'd say it was something related to the African climate that led to diminished body hair.

As far as sexual dimorphism, males are generally flashier than females, as with the peacock's tail feathers, the Betta's bright colors, the lion's mane, the colorful parts of the mandrill and the silverback's, well, silver back. Body hair dimorphism, as well as facial hair was probably used in very early times in a way similar to the attraction schemes of these other animals.

It's also possible that, since then, cultures have found hairless women to be more attractive thereby affecting selection pressures as well as shaving and waxing practices that make us think that women are significantly less hairy. AEuSoes1 08:38, 31 August 2006 (UTC)[reply]

Yes I think this last reply sums it up nicely for me. THanks for all suggestions--Light current 10:55, 31 August 2006 (UTC)[reply]

Something else to consider. While the environment can probably to be ruled out as a cause (there are lots of primates in Africa and we were the only near-naked ones), the answer of sexual dimorphism seems incomplete or incorrect to me. For one thing, different nationalities have different levels of body hair - sexual dimorphism doesn't explain why Japanese men and women are both pretty hairless, compared to some Mediterranean men and women. For another, if dimorphism was that strong a selector, I think we'd see much hairier men and much, well, smoother women across the board. I can see the argument for facial hair being a sexual signal, but body hair itself doesn't seem all that clear to me. Matt Deres 02:03, 1 September 2006 (UTC)[reply]

Enthalpy and heat

What is the difference between heat (q) and enthalpy (H)? Also, I don't understand fully what entropy is. I know the definition as the amount of disorder, but how would you measure it? Also, how does disorder relate to q/T? Thank you very much, you are great people.--216.164.200.120 04:48, 31 August 2006 (UTC)[reply]

Is this homework? Look at the links.--Light current 04:51, 31 August 2006 (UTC)[reply]

No this is not homework (and by the way, Light current, I've noticed you saying many questions are homework when they aren't), and I looked at the links, but they are somewhat confusing to me. Please could somebody help. --216.164.200.120 04:58, 31 August 2006 (UTC)[reply]

I just reread my question and noticed that it does look a lot like homework, however I assure you it is not as I do not start school again 'till September.

OK it just looked like it. How do you know the others are not homework if you didnt write them? Apologies if Im wrong. What is wrong with the article explanations?--Light current 05:05, 31 August 2006 (UTC)[reply]

H = E + PV \,

where E represents the energy of the system. In the absence of an external field, the enthalpy may be defined, as it is generally known, by:

H = U + PV \,

where (all units given in SI)

   * H is the enthalpy
   * U is the internal energy, (joule)
   * P is the pressure of the system, (pascal)
   * V is the volume, (cubic metre)

which bit is not clear?--Light current 05:10, 31 August 2006 (UTC)[reply]

I was told that q = E + PV also, which doesn't make sense. What does q really equal?

Then I also still have the question about how you measure entropy and how q/T is related to disorder. --216.164.200.120 05:17, 31 August 2006 (UTC)[reply]

Entropy in chemical systems is relatively easily determined. The change in Gibbs free energy for a reaction, dG, can be calculated readily from reaction data, since dG = -RT ln(K). and given dG=dH - (T x dS), you can simply subtract the enthalpic component dH, and find the entropic component dS at a known temperature T. its that easy ;-) Xcomradex 06:50, 31 August 2006 (UTC)[reply]

Enthalpy is basically heat, entropy is basically disorder. Things tend to:

give out heat (like a hot cup of coffee - it gives out heat);

become more disordered (like my bedroom - it keeps getting untidier and more disordered).

Physical processes tend to occur if either of the above two things can happen. If a process does both then it will happen. If it does neither then it won't, and if it does one but not the other then it's a balancing act and the temperature will decide whether it happens or not (that's why part of the equation is multiplied by T).

Systems like to get rid of energy - they can do this by giving out heat or becoming more mixed up. If it seems difficult to accept that systems can lose energy by becoming more disordered (mixed up), think about it in reverse - to make my bedroom more ordered (tidier) I have to put energy into it when I go round clearing it up.

Enthalpy is easily measured experimentally and entropy is calculated from various results and equations. Don't worry about Q/T, it just comes from rearranging the equations. Rentwa 08:16, 31 August 2006 (UTC)[reply]

Thanks for that, Rentwa! Rentwa 15:24, 1 September 2006 (UTC)[reply]

Yeah! That's just about the best darn dummies guide to Thermodynamics I ever read! Rentwa 15:25, 1 September 2006 (UTC)[reply]

Yes, thanks. You are great people - Rentwa 15:26, 1 September 2006 (UTC)[reply]

Don't mention it, it was my pleasure! Rentwa 15:28, 1 September 2006 (UTC)[reply]

I'm going to award you the barnstar for wasting your time helping ungrateful &&*^%'s! Rentwa 15:31, 1 September 2006 (UTC)[reply]

Please don't bother, it was nothing! Anyway, I'd rather have a picture of a dog in a trilby. Or a crocodile wearing a fez. Or a tram wheel and a dollop of porridge. Rentwa 15:34, 1 September 2006 (UTC)[reply]

Chin up, Rentwa. Sooner or later we all learn that providing answers to questions posed by anonymous ingrates is, like patience, its own reward. When you get to the point of making posts for the pure joy of doing so, without regard to whether or not anybody ever reads them, or if they do, what they might think of them, or of you, then you will have achieved true Wiki-transcendence. JackofOz 12:56, 3 September 2006 (UTC)[reply]

Steorn and Free Energy

What is the deal with these Irish people who claim to have proved false a large portion of scientific knowledge? It can't be true what they are saying; what are they trying to do?

Its too good to be true! (so it isnt)--Light current 04:59, 31 August 2006 (UTC)[reply]

I know, but I mean is this an ad campaign or what. --216.164.200.120 05:05, 31 August 2006 (UTC)[reply]

So far, they are maintaining it is genuine. However, as with all claimed scientific breakthroughs, it should probably be treated with skepticism until the process has successfully cleared the peer review process and the work been reproduced by other scientists. It does seem an extraordinary claim, but then again, the idea of a telephone or television was probably as fantastical at some point in time. Rockpocket 05:09, 31 August 2006 (UTC)[reply]

Probably problems with the measurements!--Light current 05:11, 31 August 2006 (UTC)[reply]

To be perfectly honest, how many legitimate scientists run ads in The Economist? Or set up flashy pages on flashy websites that seemingly were not used for any serious scientific stuffs before hand? Most legitimate scientists would at least hold back somewhat on something like this until they got some level of confirmation, rather than stirring up a media storm right away. There are also normal channels to go through instead of magazine ads. Anyways, best policy is probably to just take it with an enormous lump of salt until peer review is done with; if you took every revolutionary scientific claim completely seriously, you'd lose your mind in little time. -- Consumed Crustacean (talk) 05:21, 31 August 2006 (UTC)[reply]

The television and telephone were perfectly explainable using existing scientific theories. This "free energy" appears to directly contradict the laws of physics (which are not really "laws", but have been observed to hold true by physicsts, in this case for centuries). --Robert Merkel 05:27, 31 August 2006 (UTC)[reply]

You'll note i said "at some point in time". I'm sure, prior to the establishment of modern "scientific theories" the idea of seeing or hearing someone from another continent would be considered to contradict the "laws of physics" as we understood them at that time. Throughout history, when someone has challenged the paradigm, their works was initially mocked, see Reaction to Darwin's theory for example. I'm not suggesting the Steorn claim is genuine, but equally, it is scientifically flawed to argue it is fake based on a dogmatic adherence to so-called "laws". The fact is we do not yet know. Rockpocket 05:53, 31 August 2006 (UTC)[reply]

Yes, but at the time they were invented they were perfectly in harmony with the laws of physics as understood. This gadget isn't. And thousands of other proposed perpetual motion devices have failed before. It's not impossible this one is different, but it's pretty damned unlikely. Extraordinary claims require extraordinary evidence. --Robert Merkel 09:00, 31 August 2006 (UTC)[reply]

I'm sure there are plenty of theories or hypotheses (potential "laws") that could accomodate perpetual motion machines, its simply that they are not accepted by the mainstream as scientific. The reason they are not accepted by the mainstream is because it has hitherto proved impossible to prove (in this case empirically) and it does not sit comfortably with our current level of understanding. I completely agree that it is "damned unlikely" to be true, but if it was duplicated independently that would be extraordinary evidence. I'm willing to keep an open mind until then and not pre-judge. Remember we should be giving NPOV answers here whenever possible. Rockpocket 04:58, 1 September 2006 (UTC)[reply]

Lots of science is rubbish - thats why scientists are able to change their theories every few years! Evolution -> predicts new species evolve, but what do we observe? No new species evolve, but lots of existing ones go extinct - opposite of what theory predicts yet people still support it and in fact most Biologists actually think it's a Law of Nature!

Dark matter - cosmologists use theory to guess weight of Universe, then use observations to estimate weight - two figures disagree - sane person would assume theory wrong and evidence of eyes right, cosmologists invent special invisible matter to make theory right! [/rant] Rentwa 05:47, 31 August 2006 (UTC)[reply]

btw, we do see new species emerging, and evolution is not the oppposite of species going extinct. In fact, species that cannot evolve fast enough to new circumstances (ie, people with guns who kill more than the population can replace) would be expected to go extinct. 86.140.31.143 13:12, 31 August 2006 (UTC)[reply]

Where do you get the idea that no new species evolve? Darwin proved that species are evolving right now with the various new speciations being done on the Galapagos Islands. New species of moth were being created in Great Britain due to the sooty trees, but cleaner air has stopped the complete speciation of black and white moths. User:Zoe|(talk) 02:38, 1 September 2006 (UTC)[reply]

I'm trying to make a point about logic in scientific reasoning, or Empiricism vs. Theory, or the varying degrees of quality in scientific arguments. Darwin didn't prove anything. Just because something seems to be a plausible explanation doesn't mean it's true. 'If it looks like a duck...' may be acceptable reasoning in real life, but I think people interested in knowledge (ie scientists) should look into things more deeply. God and creationism looked like a pretty good explanation for the world pre Science, after all.

On more concrete matters - what new species have we observed on the Galapagos? I mean species that weren't there when people arrived and documented the existing fauna and have arisen since? None as far as I'm aware. Re the moths - the black form prospered during Industrial times and the lighter form is prospering now. So what? Not remotely like a new species evolving. Rentwa 13:10, 1 September 2006 (UTC)[reply]

It's obvious you're not interested in a real discussion. User:Zoe|(talk) 02:01, 2 September 2006 (UTC)[reply]

No. Humanity is responsible for wiping out lots of species, so it is a moral imperative for us to understand the mechanisms of biology so that we might correct ourselves. Evolutionary models are indispensible for investigations into the diversity of life. Dark matter is a hypothesis that makes many more important predictions than you seem to be aware of, and I can only refer to the article for those. It is necessary to hypothesize dark matter and reason about its properties so that we know how to look for it and decrease our ignorance. And no one is more careful to hedge statements about the unknown and verify theories than scientists. If you have been given a different impression by a hostile and uneducated press with no interest in the subtleties of knowledge, perhaps you should look to new sources of information. Melchoir 06:26, 31 August 2006 (UTC)[reply]

I'm ranting a little - the shortcomings of science is one of my pet bugbears (and I'm right too - see my original point - if the theories were correct it wouldn't be possible to revise them), but re your point about knowledge - my impressions were gained at an ancient British university, and it's academics, I'm afraid, who are the blindest of all to its subtleties.

This chap, btw, is quite good on free energy. Rentwa 06:46, 31 August 2006 (UTC)[reply]

A theory does not have to be absolutely correct to be useful to scientists and society alike. This is a strength of science, not a shortcoming, because we cannot and should not expect to be certain about anything. As for academics, my personal experience of researchers is that the successful ones are quite aware of the historical wrong turns their fields have taken. Melchoir 06:58, 31 August 2006 (UTC)[reply]

There's a spectrum of theory quality. Gibbs Free Energy above (misunderstanding of name possibly accounting for current interest) is brilliant, as is most of Thermodynamics. Unfortunately (as I'm sure you would agree) that's one end of the spectrum.

And I disagree completely with your observations on successful researchers (perhaps I'm just bitter!) Orthodoxy is the thing that counts. Rentwa 07:13, 31 August 2006 (UTC)[reply]

Fair enough. I won't claim to be a sociologist! Melchoir 08:32, 31 August 2006 (UTC)[reply]

No, honestly, I was ranting! (Don't_disrupt_Wikipedia_because _you're_too_mean_to_pay_for_therapy) ;-) Rentwa 08:39, 31 August 2006 (UTC)[reply]

Atoms

Can scientists directly see atoms? What kind of microscopes are used? If it's still impossible, what capabilities would a microscope require in order to be able see the atom?

I was just wondering. I assume electron microscopes are used to get a sense of the election cloud surrounding an atom's nucleus but viewing the nucleus itself isn't yet possible. I'm not sure though. - Pyro19 08:53, 31 August 2006 (UTC)[reply]

Microscope is a good (and obvious) starting point. That leads you to Scanning tunneling microscope. Another one would be atom, where you can search for 'microscope'. DirkvdM 09:17, 31 August 2006 (UTC)[reply]

A common way to get a look at atoms (be it indirectly) is X-ray crystallography. And another method (actually the first) to actually visualise atoms is the field ion microscope. an actual picture [2]. Xcomradex 10:25, 31 August 2006 (UTC)[reply]

Wow, never knew atoms were so slimy-looking. :) DirkvdM 09:14, 1 September 2006 (UTC)[reply]

With all of these visualizations there are a lot of assumptions which have to be made about the data—you are never really looking at the "atom itself" in the way that one normally thinks of "looking", so it is all "indirectly" in a sense. But once you start really interrogating what "looking" means at the atomic and subatomic level, it gets pretty hard to say that you see anything "directly". In any case, the most famous picture of individual atoms is the IBM logo made out of 35 Xenon atoms. As you can see, they look more like probability functions than what one might expect an actual atom to "look like" from a human point of view. --Fastfission 14:54, 31 August 2006 (UTC)[reply]

Claiming that's the IBM logo is a bit much. Let's be reasonable here and just call it what it is, the letters IBM. freshofftheufo ΓΛĿЌ 13:02, 1 September 2006 (UTC)[reply]

The definition of "looking" is something to note here. The most common way to "look" at something is to throw things at it, and see what they do. That is why we make particle accelerators (atom smashers), so we can "look" at things that we can't "see." In normal life, we do this. One could say when you switch on the light bulb, photons fly out and bounce off of objects, and the photons eventually reach your eye. Based on the qualities of the photons that reach your eye, you "see" objects. — [Mac Davis] (talk) (Desk|Help me improve)

Wait, there's something I'm still not getting. Is it impossible to see an atom due to quantam effects or something? That picture that Xcomradex linked to, are those little round balls actual individual atoms or are they an approximation? - Pyro19 15:24, 1 September 2006 (UTC)[reply]

You can only clearly "see" something using a wavelength that's quite a bit smaller than the size of the object you're trying to see. Oridnary light in the visible spectrum clearly won't do for visualizing individual atoms; the atoms are smaller than the wavelength of the visible light. So you'll never be able to use your eyes directly through some kind of ultramicroscope to see an atom. That's where the shorter wavelengths used in X-ray crystallography come into play. But even those are pretty big and the atoms aren't imaged individually. Instead, they act en mass like a diffraction grating.

Instead, we use particles that have the equivalent of a very short wavelength (those "ions" that were mentioned above in the field ion microscope).

Alternatively, we can use actual touch (or the quantum equivalent of "close enough"). That's how the various scanning tunneling microscopes, atomic force microscopes, and the like work.

Atlant 00:33, 6 September 2006 (UTC)[reply]

Distance traveled by a soccer ball when kicked in different angles.

When a soccer ball is kicked at an angle exactly paralled to the ground, that is , making an angle of 0 degree with the ground, will it travel more horizontal distance or when it is kicked making a certain angle with the ground ? Force applied in both the cases is taken as same.

User : Sanchit

I'll leave to that someone more capable, but essentially zero degrees would either mean slipping or rolling, right? Well, it depends on the material of the ground : grass, ice,... Evilbu 11:32, 31 August 2006 (UTC)[reply]

I think you have to clarify your question... do you mean kicking it down or up? If you kicked it up it would most certainly travel further than kicking it along the ground for angles less than 45 to the ground. Kicking it downwards should cause it to bounce and lose a lot of energy on impact with the ground, but exactly how much energy it loses is hard to say... you might have to stage a real-life trial to figure that out. freshofftheufo ΓΛĿЌ 12:03, 31 August 2006 (UTC)[reply]

I think the question is, essentially, what is the optimum angle to achieve the greatest distance. According to our trajectory article, this is 45 degress.--Shantavira 13:57, 31 August 2006 (UTC)[reply]

While 45 degrees is absolutely correct for idealized cannonballs, soccer balls will behave differently. I'd put "optimal" at a lower angle, say 20 to 30 degrees, to keep most of the air time while reducing the energy lost at landing and improving the horizontal speed component for the post-landing roll. — Lomn | Talk 15:12, 31 August 2006 (UTC)[reply]

It is 45 degrees if the ball does not spin. Forward spin or back spin will alter that a bit. --Kainaw ^(talk) 15:14, 31 August 2006 (UTC)[reply]

When a goalie kicks it as far as he can, it is at a much greater angle than 30 degrees. --liquidGhoul 15:15, 31 August 2006 (UTC)[reply]

It's worth noting that when the goalie kicks the ball, the ball never goes as far as it could. There are always players in the way; those players aren't going to let a ball bounce and roll out to its maximum distance. The angle at which the ball leaves the goalie's foot is going to be something of a compromise.... TenOfAllTrades(talk) 15:21, 31 August 2006 (UTC)[reply]

45 degrees is correct for ideal cannonballs on the moon—that angle doesn't take into acount the effects of air resistance. When we look at bouncing and rolling, then you have to take into account the properties of the ball and the grass; it's a mess. TenOfAllTrades(talk) 15:21, 31 August 2006 (UTC)[reply]

...only if the moon has a radius much larger than the cannon's range, and its muzzle velocity is small compared to the moon's escape velocity. Skimming those articles for numbers, the assumption doesn't look so good. So really, 45 degrees is correct in thought experiments and textbooks. Melchoir 17:18, 31 August 2006 (UTC)[reply]

Okay, okay. 45 degrees is the optimum in an airless environment where the curvature of the surface is negligible compared to the length of the ball's trajectory and the gravitational acceleration is approximately uniform throughout the ball's flight. Once you start removing those assumptions the calculation quickly starts getting difficult. To a first approximation, since it has air resistance, the best angle to kick a soccer ball for maximum range would be a bit below 45 degrees, although I can't calculate it exactly since I don't know the drag coefficient of soccer balls, and am not taking into accounts the effects of spinning the ball... — QuantumEleven 07:34, 1 September 2006 (UTC)[reply]

specific question for medicine/hematology

Dear Sirs,

I have read a certain writing on a disease/disorder called hyperkaliemia and I understand that it is composed of hyper-, kalium (potassium)and (a)emia (referring to blood). Where can I find more specific info on the disease because I could not find anything in the Wikipedia. Greatful in advance for any help from your specialists.

Very truly yours, Mr. Antti Stenberg Helsinki, Finland82.181.113.180 12:06, 31 August 2006 (UTC)[reply]

You were close. It's spelled Hyperkalemia. -- Plutortalk contribs 12:26, 31 August 2006 (UTC)[reply]

Redirected. You can help! freshofftheufo ΓΛĿЌ 12:39, 31 August 2006 (UTC)[reply]

Surviving by drinking seawater

I have read accounts of shipwrecked people who claimed to have survived by drinking seawater, while other accounts--including Wikipedia--state that this is likely to lead to kidney failure. What is the correct answer? --Mugogo

Kidney failure, salt water just doesn't quench thirst, it makes it worse. Even if you could drink large amounts of it, it wouldn't do you any good unless you made a point of distilling it first--VectorPotential^{71.247.243.173} 16:10, 31 August 2006 (UTC)[reply]

Also, try not to eat things that will not benefit you after digestion. If you eat your leather boot, your stomach may be filled, however you are killing yourself by spending more energy trying to digest a boot that has no nutritional value to you whatsoever. Regarding the water, you can distill seawater or urine, then drink the product. Solar stills are the most common and efficient way of doing this. — [Mac Davis] (talk) (Desk|Help me improve)

Do you actually need to distill the urine? I heard it can be drunk raw/neat/warm. Our page:

Urine on the other hand contains salt, which makes it unsuitable to drink. You can, however, make drinkable water from urine by distilling it.

So if there was little or no salt you could drink it. Otherwise you could try to remove the salt somehow.

--Light current 16:45, 31 August 2006 (UTC)[reply]

The other question is the stuff that causes the yellow/brown pigmentation of urine. Also theres urea. Im not sure what effect that has if it builds up in the body.--Light current 17:17, 31 August 2006 (UTC)[reply]

Too much urea will become toxic. People who wet the bed also know that it causes a nasty skin rash. The brown pigmentation is due to red blood cells and their broken down constituents that have made it through the renal filters. You shouldn't drink distilled urine unless you could guarantee you've distilled pure water out of it, which is unlikely if you're stranded at sea with a makeshift distiller. Nimur 17:38, 31 August 2006 (UTC)[reply]

You could always try eating the cabin boy.--Shantavira 17:30, 31 August 2006 (UTC)[reply]

Having quickly read that art, it seems to me they were unjustified in eating him after only 8 days or so. Im sure humans can survive a coulpe of weeks with no food.!--Light current 17:45, 31 August 2006 (UTC)[reply]

Actually, the yellow color comes from urochrome and bilirubin. While excess levels of bilirubin in the blood can be toxic, I am unsure whether ingesting them would cause them to accumulate in the body or whether they would be broken down by the digestive process. Plus, sunlight helps the body breakdown bilirubin, thus if you are stranded on a raft out at sea and decide to drink your urine, there would be plenty of sun to help you brak down all that bilirubin! Nrets 17:36, 31 August 2006 (UTC)[reply]

So the moral of the story is: make sure yuo take a small still with you into the life boat and drink as much as you can before abandoning ship! Also looks like that art on urochrome needs expanding considerably.--Light current 17:49, 31 August 2006 (UTC)[reply]

However, drinking pure distilled water is not good for you either, as it contains no electrolytes and will wash everything out of your body. You may be best off with neat urine (for the electrolyes) diluted with the distilled stuff (might taste better too!)--Light current 18:00, 31 August 2006 (UTC)[reply]

Why would that be? I never considered it, but always thought your body's maintenance, requiring water— distilled water would suffice somewhat. Ok, bad sentence construction, but you get what I am trying to say. — [Mac Davis] (talk) (Desk|Help me improve)

Distilled (pure or deionised water) I believe is very attractive to ions of potassium , sodium etc in the body and will leach them out leaving you short!--Light current 19:34, 31 August 2006 (UTC)[reply]

Add a teaspoon of sea water. --liquidGhoul 23:54, 31 August 2006 (UTC)[reply]

After the revolutionary army (as far as one can call it that) landed in Cuba they got into big trouble and after a while found themselves with little drinking water in a saltwater environment. So Che said he had read that if you mixed the drinking water with salt water you could double your available water. So they tried that. This made Che very impopular over the next few days. :) DirkvdM 09:25, 1 September 2006 (UTC)[reply]

A very old military practice is to put salt in drinking water - not to increase the water, but to increase the body's ability to hold water. A little salt will increase absorbtion. Too much salt, and you lose water. You judge it by how much you urinate. Keep adding salt until you urinate much less frequently. Then, if you continue adding salt, you will urinate a LOT more (and it is a bit painful). I was lucky. My body likes two standard issue packets of salt per standard issue canteen. No worrying about half-packets or anything like that. --Kainaw ^(talk) 19:11, 1 September 2006 (UTC)[reply]

I understand that one shouldn't have more than 6 grams of salt per day, as a nutritional rule of thumb. While this information generally relates to adding salt to meals, I believe it serves as a rough average of how much daily salt intake is considered "healthy" (by British standards.) CptJoker 02:08, 3 September 2006 (UTC)[reply]

But the gram is an SI unit, so British standard don't apply here. DirkvdM 05:27, 3 September 2006 (UTC)[reply]

Physics

Why are Germanium and Silicon which have 4 valence electrons classified as semiconductors, whereas Carbon which also has 4 valence electrons is vlassified as an insulator?…—Preceding unsigned comment added by Salvadesswaran ps (talk • contribs)

Diamond#Electrical properties might help. It's not much, though. Melchoir 16:43, 31 August 2006 (UTC)[reply]

Carbon is not an insulator. I think it may be classed as a semiconductor.--Light current 16:52, 31 August 2006 (UTC)[reply]

Graphite is a conductor. Nimur 17:10, 31 August 2006 (UTC)[reply]

For the full story, there are many allotropes of carbon. I think diamond is the most relevant to the analogy with silicon and germanium. Melchoir 17:12, 31 August 2006 (UTC)[reply]

Agreed - depends on the form. Its either a semi conductor (diamond) or a conductor. I dont know of any insulating forms.--Light current 17:32, 31 August 2006 (UTC)[reply]

In other news, check out the French link under "in other languages" for Aggregated diamond nanorods. Honestly, nanobaguettes? How do they say that with a straight face? Melchoir 17:38, 31 August 2006 (UTC)[reply]

Diamond is a semiconductor. I went to an interesting lecture last year on the current research into diamond semiconductor research and promptly forgot most of it, but I do remember that diamond semiconductors can operate at my higher temperatures than silicone and are also completely non toxic in the body (andriods anyone)? Theresa Knott | Taste the Korn 17:39, 31 August 2006 (UTC)[reply]

and don't forget the bigger picture, the periodic table, and metalloids. Xcomradex 21:38, 31 August 2006 (UTC)[reply]

Whether a solid material is a conductor, semiconductor or insulator depends on a parameter called the band gap, the energy difference between the "valence band" (where there are electrons) and the "conduction band" (where they would have to go in order to help conduct electricity). In conductors, there is no band gap, so the electrons are free to conduct. In insulators, the band gap is "large", and there is no conduction. In semiconductors, the band gap is "small", so that a few electrons can be kicked up into the conduction band by thermal excitation (their heat energy), especially if they are helped along by the trick called doping. Clearly the boundary between "small" and "large" band gaps is fuzzy. Diamond has a larger band gap than silicon and germanium, and under normal conditions behaves mosty like an insulator (being essentially insulating to electricity, being transparent to light, etc.). However, its band gap is much smaller than those of typical insulators, and diamond does behave as a semiconductor at higher temperatures, or if doped. There is a fair bit of research on diamond semiconductor devices, so stay tuned for cool products in the future. mglg_(talk) 22:39, 31 August 2006 (UTC)[reply]

Science of gayness

What disturbances in childhood cause gayness? Also, if there is a genetic component(as found in fruit flies), to what extent does it affect humans? --216.164.200.224 16:58, 31 August 2006 (UTC)[reply]

Check the homosexuality or human sexuality articles for a baseline. This is a topic which doesn't have a precise answer; a lot of research is still ongoing. Nimur 17:09, 31 August 2006 (UTC)[reply]

Doesn't the relative commonness of homosexuality rule out genetics? Two people of the same sex can not produce a baby of their own passing on their genes if they are fittest? I guess we would have to go to Papua New Guinea to see how gay people are there and compare it to, say, the United States. — [Mac Davis] (talk) (Desk|Help me improve)

Mac you have a lot to learn about genetics. By that argument, brown eyes and black hair and heterosexuality have no genetic basis-- in fact, by that argument, being male or female has no genetic basis. alteripse 20:05, 31 August 2006 (UTC)[reply]

A putative gene for gayness might predispose for strong sexual attraction towards men and reside on an autosomal chromosome, and thus create this attraction irrespective of whether the carrier was male or female. The benefit of increased reproduction of female carriers might outweigh the reduced reproduction of male carriers of the gene. --N·Blue^talk 19:51, 31 August 2006 (UTC)[reply]

I've heard of several sets of identical twins where one was gay and one was not, so it's unlikely to be purely genetic. At the same time, I would think it extremely unlikely that something like this wouldn't have a genetic component. At a personal guess, there is probably an inherited tendency which, for whatever reason, is sometimes expressed and sometimes not. Skittle 20:14, 31 August 2006 (UTC)[reply]

Fruit flies have nothing to do with human genetics—they are just model organisms with which we understand different aspects of how genetics works; they do not tell us anything much about the actual expression of human genetics (anymore than human genetics would tell us about fruit flies). --Fastfission 20:21, 31 August 2006 (UTC)[reply]

What do homosexuals call themselves? Homosexuals or gays? I dont theink the original title was offensive to anyone. Please change it back! 8-(--Light current 20:27, 31 August 2006 (UTC)[reply]

What disturbances in childhood cause gayness? I admit I cringed when I read "disturbances", as it seems to imply that it takes something wrong/bad/weird (i.e., not an amoral event) to turn a child gay or something. But, despite the poor word-choice, there's a good question here.

First off, it's important to not think of sexuality in binary terms; the Kinsey scale or Klein Sexual Orientation Grid are sort of a crude measurements of where one might fall in this spectrum. Biology and sexual orientation & Choice and sexual orientation may have more useful, relevant information, too. Whether one is "gay" is a quasi-subjective establishment--obviously those that have only ever been exclusively attracted to and sexually active with one sex are pretty clearly "straight" or "gay", but there's a very large portion of society that doesn't fit perfectly into those categories.

For the genetics: there will (likely) never be a single definitive, all-encompassing "gay gene" discovered because, frankly, it would most likely be readily selected against. But, there are genetic regions that associate with homosexual traits.[3] These may, among other things, encode differential development of the sexual dimorphic nucleus, efficacy of aromatase, or perhaps some temporal difference in hormonal signaling during fetal development, for example. It's still largely unexplored.

Finally, the preponderance of scientific evidence is that human sexuality is determined, in large part, by genetic and epigenetic control of developmental processes (and maybe some important effects in olfaction). But, probably not 100%...the way I'd think of it: imagine that spectrum as simple line or axis, continuous rather than segmented into integers as in the scales above; one's genetic & epigenetic characters probably define a narrowed region of said spectrum as the destinations for one's sexual identity. Environmental factors, in and out of one's control (such as maternal hormonal effects in utero or sociological forces), narrow it to a single (but not necessarily immobile) point. -- Scientizzle 23:59, 31 August 2006 (UTC)[reply]

Very nice answer, Scientizzle *round of applause* Rockpocket 04:46, 1 September 2006 (UTC)[reply]

Thanks. -- Scientizzle 04:57, 1 September 2006 (UTC)[reply]

On NorwegianBlue's comment: yes, that would make sense. See also [4] which has a similar but more complicated idea. – b_jonas 13:02, 2 September 2006 (UTC)[reply]

biogas

how do biogas reactors produce pressurized methane without pumpos?

Anaerobic digestion has your answer. The way I see it, they just grind up the pumpos and throw it in! --Zeizmic 20:11, 31 August 2006 (UTC)[reply]

Carbon

What is it about carbon that allows it to have some many allotropes and forms with such differing properties. Is any other element so versatile. Im not a chemist, so can you keep it simple? Thanks--Light current 20:16, 31 August 2006 (UTC)[reply]

Allotropy also makes the point of elements having multiple oxidation states (many workable arrangements of electrons) and variable co-ordination numbers (many workable arrangements of neighbouring atoms) (both apply to carbon) having more allotropes. and there are other elements with large amounts of allotropes too,eg. black, white and red phosphorus for example; oxygen, ozone and tetraoxygen, and sulfur has even more than carbon. Xcomradex 21:47, 31 August 2006 (UTC)[reply]

So sulfur could produce some interesting forms? Is that right? Are all these elements in a particular region of the periodic table as well?--Light current 21:52, 31 August 2006 (UTC)[reply]

Looks like theyre all in the non-metals part. How gratifying! So Selenium may have the same allotropic versatility as well?--Light current 21:57, 31 August 2006 (UTC)[reply]

you got it. there's red powder selenium, red crystalline selenium, as well as the useful gray semi-metallic selenium. Note that one of the allotropes of sulfur is S₈; likewise selenium has an allotrope Se₈. don't you love the periodic table B-) Xcomradex 22:08, 31 August 2006 (UTC)[reply]

Seems good to me!--Light current 22:10, 31 August 2006 (UTC)[reply]

If you're in search of more allotropic fun, or other periodic table stuff, [5] is good site. Xcomradex 22:22, 31 August 2006 (UTC)[reply]

Isn't this versatility of carbon a reason it is a basis of life on Earth? And if so, could life then be based on something like Selenium or Sulphur? DirkvdM 09:31, 1 September 2006 (UTC)[reply]

yeap. alternative biochemistry. Xcomradex 11:05, 1 September 2006 (UTC)[reply]

Silicon is the only other equivalent to carbon, the others differ in ways, but can be made to work. Philc _T^E_C^I 15:23, 1 September 2006 (UTC)[reply]

Silicon is a rather poor substitute for carbon, mainly due to its lower electronegativity and the larger size of its p-orbitals. Pure silicon analogues of organic compounds, such as silanes, simply don't hold together as well, especially where double bonds are involved. Silicon can replace a carbon atom in a mostly carbon molecular framework, but such organosilicon compounds are often reactive and break easily apart at the silicon atom. See also Silicon#Silicon-based life. —Ilmari Karonen (talk) 19:45, 2 September 2006 (UTC)[reply]

Orangutans in TV and Movies

I have seen trained Orangutans in American movies and Television,.How is it legal for for Animal trainers (and other private individuals) to own and exhibit Orangutans when they are an endangered species, And where are these people buying them from? I know they are not imported from the wild anymore.—Preceding unsigned comment added by 74.234.31.7 (talk • contribs)

Unless they're eating and/or sterilizing the Orangutans, I don't suppose that simply having them on film would do much to jeopardize their conservation status--71.247.243.173 22:48, 31 August 2006 (UTC)[reply]

there is a danger that such orangutans may become acustomed to the movie star lifestyle, and be unable to find bagels in the wild. Xcomradex 22:55, 31 August 2006 (UTC)[reply]

How much do they get paid for appearing in films?--Light current 23:25, 31 August 2006 (UTC)[reply]

I've heard they work for peanuts, but that may be elephants--71.247.243.173 23:30, 31 August 2006 (UTC)[reply]

The problem with using them, is that people are making money from an endangered species. If it is profitable to exploit them, then it is more likely people will take them from the wild. Also, most zoos and such have breeding colonies, so they can release them into the wild. If the orangutan is being used for television instead of being in a breeding program, that will lower the diversity of those which are released, and lower their chance of survival as a species. --liquidGhoul 23:44, 31 August 2006 (UTC)[reply]

Seeing as how our article on Orangutan#In_popular_cultureOrangutans, only has 3 pop culture references, one of which is a cartoon, I don't think they actually are used in film/TV all that often, if at all--71.247.243.173 00:18, 1 September 2006 (UTC)[reply]

The last one I remember was Clyde appearing with Clint Eastwood.--Light current 00:20, 1 September 2006 (UTC)[reply]

Dunstan Checks in , George of the Jungle, Baby's Day Out, Fear and Loathing in Las Vegas,Babe 2 Many comercials for among other things Credit Cards, Tang, Domino's pizza

The last time I saw Orangutangs (sp?) was in Serious Jungle and that program was about conservation and they were still in the wild. - Mgm|^(talk) 08:04, 1 September 2006 (UTC)[reply]

Yeah, last time I checked, it was a gorilla in George of the Jungle (film), and wasn't it a robot? freshofftheufo ΓΛĿЌ 12:47, 1 September 2006 (UTC)[reply]

I was not refering to George's talking side kick "Ape" .There were orangutans as background characters in the moive along with Chimps , Capuchin Monkeys and other primates.

Yes, I do believe there were. In cages? At a zoo? It's been a long time since I saw that movie. freshofftheufo ΓΛĿЌ 07:02, 2 September 2006 (UTC)[reply]

automotive

I am trying to figure out more information on car's body stiffness. Can you help? —Preceding unsigned comment added by 65.169.154.2 (talk • contribs)

Cars with frames tend to be stiffer than unibody cars. Modern cars tend to be intentionally designed not to be stiff, so they will collapse in a severe impact, thus reducing the deceleration effect on the passengers. See crumple zones. What other info do you want ? StuRat 00:11, 1 September 2006 (UTC)[reply]

The term can be used in a variety of ways. StuRat has explained how compressional stiffness is important to a car: safety is increased in cars which "crumple" within certain bounds. Car manufacturers often will subjectively rank torsional stiffness between models. A higher torsional stiffness will help keep all four wheels on the road in tight turning situations. A lower torsional stiffness is why convertibles often handle "worse" than similarly specified coupes. Also important is resistance to bending, or sheer forces. This type of stiffness is more complicated. Anti-roll bars, for instance, will be more resistant to sheer stresses and help both tires on opposite sides of the car stay in synch. However if sheer stress is increased too much, any stresses or damage that would have previously only affected only one side of the car will now affect both sides. Stiffness is also a term used to describe various shock-absorbing apparati between the wheels and the chassis, but since you asked specifically about the body stiffness, I'll spare you.Tuckerekcut 00:34, 1 September 2006 (UTC)[reply]

September 1

nature cure

respected whomsoever,i am a naturopathy and would like to have answer for a question in water therpy of nature cure. "Why do we use cold water therapy?" I need to have a scientific approach to this answer

We need to have a slightly more detailed question.--Light current 03:41, 1 September 2006 (UTC)[reply]

this could be interesting, given naturopathy and science are pretty much mutually exclusive Xcomradex 03:56, 1 September 2006 (UTC)[reply]

Check out Hydrotherapy for history and techniques, Naturopathy for references to scientific (and governmental) assessment.---Sluzzelin 05:42, 1 September 2006 (UTC)[reply]

Unknown green insect

What is this insect? Which species, family, or order? The photo was taken in Gyeonggi-do, South Korea. --Kjoonlee 03:24, 1 September 2006 (UTC)[reply]

Some type of walking leaf, I would guess. Here's a pic of the Malaysian Walking Leaf: [6]. StuRat 03:34, 1 September 2006 (UTC)[reply]

I give up, this ones too hard. I'm guessing that the two front legs are held up in front of it's face or something, but I can't find anything like that with a flat back, and I've just sifted through a few thousand images. It seems leaf insect is a bit more technical than walking leaf, though they both refer to the (huge) Phasmatodea (and the possibly more relevant Phylliidae) anyways. freshofftheufo ΓΛĿЌ 12:40, 1 September 2006 (UTC)[reply]

Thank you. :) According to SNU's insect taxonomy website, It's Neotituria kongosana. Here are some other photos: [7] --Kjoonlee 13:31, 1 September 2006 (UTC)[reply]

A sort of leafhopper. Cicadellidae, Ledrinae, Petalocephalini, Neotituria kongosana. --Kjoonlee 13:46, 1 September 2006 (UTC)[reply]

I susupected it was some sort of leaf hopper, but I couldn't find any that had such a flat shell structure. Most of them seem to look like the first 2 in that link you gave. All of my sources were English, though, and about 99% of the images were from the US, so I guess that explains why I couldn't get any closer : (. freshofftheufo ΓΛĿЌ 06:59, 2 September 2006 (UTC)[reply]

Hoodia Gordonii

What is it and how does it work and how much of it do you take?

See Hoodia. Melchoir 04:41, 1 September 2006 (UTC)[reply]

Hoodia trust for medical advice? Edison 17:01, 1 September 2006 (UTC)[reply]

neutron star

what is a neytron star.is it possible to get some or addsome neutron in that star?

All is revealed at neutron star. Search first; it's quicker.--Shantavira 06:18, 1 September 2006 (UTC)[reply]

First make sure you understand your own question, though. DirkvdM 09:34, 1 September 2006 (UTC)[reply]

anaytrunstar is a starthat is not tronn but instedaq it is neytron.mickjagger is arock star...if he had some neyutron maybe heedbe a neutron start Loomis 21:01, 3 September 2006 (UTC)[reply]

medical

If an injured swimmer was to drown and the red blood cells found in the lungs were swollen and had burst, did the person drown in fresh water or sea water? Given that the tonicity of sea water is greater than that of the cytoplasm of blood cells , and the tonicity of fresh water is less than that of red blood cells, explain how you reached your conclusion. What process has occured in this situation? thanks Johanna

Sorry, you should probably do your own homework. Tonicity might be a good place to start. -- Plutortalk contribs 12:27, 1 September 2006 (UTC)[reply]

Actually, you should ask for better homework questions. People who drown have water in their lungs, not blood. Their blood is in their circulatory systems, before, during, and after drowning. The question should allude to lysis of RBCs within the lung capillaries, not "in the lungs". Freshwater is hypotonic and flows rapidly through the pulmonary capillaries overloading the heart and causing lysis of RBCs with K⁺ release. Death is rapid. Saltwater is hypertonic and there is no mass fluid transfer; death is slower and has a strong asphyxial component. - Nunh-huh 21:08, 1 September 2006 (UTC)[reply]

There are lots of ways to die of immersion, including sudden arrest, air embolization, asphyxial suffocation without water inhalation, etc. See [8] for a fairly good overview. The question is easy based on test-taking skills: the questioner is obviously ignorant about drowning and doesnt care about drowning but wants to see if you understand the isolated concept of hypotonic versus hypertonic fluid effects on rbcs. The question would be the same if they asked what would happen to rbcs dropped into a hypotonic or a hypertonic solution.alteripse 23:55, 1 September 2006 (UTC)[reply]

Difference between PRECISION & ACURRACY?

What is the clear-cut distinction between precision & accuracy?

Accuracy and precision. Weregerbil 12:58, 1 September 2006 (UTC)[reply]

A nice example is that if I said I was 6.32456m tall, it would be high precision but low accuracy. If I said I was 1.5m tall, it would be less precise, but more accurate. —D a niel (‽) 13:13, 1 September 2006 (UTC)[reply]

Why. How tall are you?--Light current 20:42, 1 September 2006 (UTC)[reply]

Assuming that the number of figures is used as an indicator of the precision. —Bromskloss 13:50, 1 September 2006 (UTC)[reply]

It ought to be, when reporting a measurement. See significant figures. TenOfAllTrades(talk) 15:24, 1 September 2006 (UTC)[reply]

Well, the real difference, is that PRECISION is what they ask you in about in a freshman lab course, where as ACURRACY is what they ask you about in lecture, 2 completly different types of homework you want us to do for you--71.247.243.173 19:03, 1 September 2006 (UTC)[reply]

Kid in a natural history museum: "Hey mister, how old is that dinosaur ?"

Guard: "200 million and 8 years old."

Kid: "You mean 208 million years old ?"

Guard: "No, I mean 200 million and 8."

Kid: "But how do you know so precisely ?"

Guard: "Well, it was 200 million years old when I started working here 8 years ago, so..."

StuRat 00:59, 2 September 2006 (UTC)[reply]

Another way of thinking about precision vs. accuracy is that, even though you were inaccurate when you mis-spelled accuracy as acurracy, we still knew precisely what you meant. JackofOz 12:35, 3 September 2006 (UTC)[reply]

Should this one be on the language RefDesk, Stu? :) Loomis 20:57, 3 September 2006 (UTC)[reply]

No, because they are simply synonyms in general English, it's only in the scientific area where the definitions differ. StuRat 08:47, 4 September 2006 (UTC)[reply]

Accurate: acceptable, truthful value. Precise: Getting the same value repeatedly. --Proficient 17:31, 4 September 2006 (UTC)[reply]

I wouldn't say they're synonyms in English. For example, it would be a very accurate but very imprecise statement to say that roughly a bit more than half of the human population is female, whereas it would be a very precise yet very innacurate statement to say that precisely 48.563982% of the world population is female. Also, one can say "I want you to be at my office at precisely 11:42am", whereas the statement "I want you to be at my office accurately at 11:42am" wouldn't seem to make much sense at all. Loomis 08:33, 6 September 2006 (UTC)[reply]

You are using the math/science meanings. A plain English usage might be "he is admired for the precision/accuracy of his Oscar picks". StuRat 07:36, 7 September 2006 (UTC)[reply]

Another example: My chemistry teacher said that 1 litre and 1.00 litre of a particular liquid mean different things. The reason: 1 litre meant was that you had between 0.5 and 1.5 litres. 1.00 litres actually meant that you had between 0.995 and 1.005 litres. Maybe precision is whether you use 1, 1.0 or 1.00, and accuracy is whether you measure it to be 0.997, 1.001 or 1.003? -- Chuq 10:18, 6 September 2006 (UTC)[reply]

The level of "Precision" seems to be concerned more with the level of detail, and far less concerned with the veracity of a statement, whereas "Accuracy" tends to far more concerned with veracity, and far less concerned with detail. Loomis 22:32, 6 September 2006 (UTC)[reply]

Cattle in a feedlot

I know that before slaughter, many cattle are housed in a feedlot to be fattened up. I would like to know about how long an animal will typically stay in the feedlot. ike9898 13:08, 1 September 2006 (UTC)[reply]

According to this page that used to be on Harris Feeding Company's website, "cattle typically spend approximately 12 to 16 months grazing; then, at 650 to 750 pounds, enter the feedlot for about 3 to 4 months to gain an additional 400 pounds or so." -- Plutortalk contribs 15:00, 1 September 2006 (UTC)[reply]

Could you add that to the article? Rmhermen 16:51, 1 September 2006 (UTC)[reply]

Yeah, I'm also trying to find another source. ike9898 20:37, 1 September 2006 (UTC)[reply]

Acetone as an additive for gas and diesel?

I read that adding minimal amounts of acetone to gasoline and diesel would increase mileage considerably. My question is if that is really the case. Also, of course, the car should not get damaged if one were to do this (especially the catalyst). Last but not least, would this increase, decrease or not affect exhausts at all? Thanks for your answers, RichiH 13:25, 1 September 2006 (UTC)[reply]

Off the top of my head, I can't think of any reason why acetone should improve mileage, mile per joule, more than any other fuel, so it sounds wrong to me. Again, off the top of my head, the only additives that make a difference to engine operation beyond their calorific value are things that affect the octane rating of the fuel (and they really affect smoothness of operation rather than efficiency), and I can't see acetone doing this.

Catalysts are primarily damaged by lead additives which coat the Pt/Pd, acetone certainly wouldn't do this.

The major problem I see with using acetone as a fuel is that it mixes with water, so using pure acetone would mean having water in the engine which would corrode it. Same reason why you dont use washing-up liquid as a lubricant, even though it's ideal in most other respects.

Actually this is an advantage. Having Acetone absorb the water and carry it through the engine is a good thing, unless you are talking about a lot of water. 12.41.204.3

No it isn't. You shouldn't contribute to topics in which you have no formal knowledge, particularly to contradict people who have. You've also been told before to sign your comments. Rentwa 17:21, 1 September 2006 (UTC)[reply]

The burnt acetone would come out in the exhaust just like the other burnt chemicals - it wouldn't have any disproportionate effect on exhaust.

If you can provide a link to the original article or quote it, it might help. Rentwa 13:54, 1 September 2006 (UTC)[reply]

I would have provided the link, but it's on another box and i do not have access to that, right now :/ RichiH 18:04, 2 September 2006 (UTC)[reply]

I think i found the page, again: [9]. Googling also showed this: [10] which points to here: [11] RichiH 18:18, 2 September 2006 (UTC)[reply]

Thanks Richi. The molecular theory sounds pretty good (so did the theoretical explanations of Cold Fusion). Petrol/Diesel are mostly hydrocarbons, like sticking to each other, don't like sticking to acetone. Mix a bit of acetone in and it breaks up the whole thing, so there's a lot less sticking going on. And hey presto, the fuel is easier to vapourise, burns more efficiently etc etc.

However, from a thermodynamic point of view this is saying that a little drop of acetone is doing one hell of a lot of work - it's like putting a drop of something into a cup of water and the water boiling. You can get a rough idea of the amount of free/magic work the acetone is supposed to do from the claimed fuel efficieny improvements (laughable). And since the claim refers to this special mixture having more potential energy than the fuel and acetone independently, for it to work the exhaust gasses exiting the engine would have to be different in some way from a mixture of burnt fuel and acetone, and obviously they won't be. So complete bollocks. :) Rentwa 19:21, 2 September 2006 (UTC)[reply]

The third source tries to claim that atomisation (better description than vapourisation) is incomplete and fuel is wasted - not true. Modern engines, especially with engine management systems tend to run at trace knock (lean burn) - no significant unburnt fuel. And since the catalyst is effectively a final combustion chamber, if there was any large amount of unburnt fuel the catalyst would be getting very hot indeed. Finally, molecular vibrations aren't relevant to the discussion on the mixture, polarity is, and I've never heard a real scientist talk about sluggish molecules or 'natural frequencies'. Total bollocks! Rentwa 21:21, 2 September 2006 (UTC)[reply]

Thanks Rentwa, i did think it sounded too good to be true. Still, a pity ;) RichiH 12:40, 3 September 2006 (UTC)[reply]

The acetone thing is an urban legend. Mythbusters even tackled it--it doesn't work. All it will do is damage your paint job if you spill... -- Scientizzle 14:22, 1 September 2006 (UTC)[reply]

It would definately hurt your paint job as nail and car paint are very similar. I even tried this, once. (No, not on a car.. ;) RichiH 18:04, 2 September 2006 (UTC)[reply]

I can't see how acetone would help; I can see how it would hurt. It's combustion properties are going to be different from gasoline (I can't be bothered to dig out exactly how, at the moment) so it will burn hotter/faster or colder/slower than gasoline. Adding it into the mix in any concentration high enough to have an effect is either going to result in added wear and tear on the engine and increased output of nitrogen oxides (if it burns hotter) or incomplete combustion and increased output of unburned fuel, soot, and carbon monoxide (if it burns colder). Acetone may also attack engine components, as Rentwa notes it will allow water into the fuel, and it will probably harm the finish on the car if spilled. Finally, acetone has a much higher vapour pressure than regular gasoline, resulting in greater losses to atmosphere during filling and increased risks when used in confined spaces. TenOfAllTrades(talk) 15:22, 1 September 2006 (UTC)[reply]

Acetone burns faster, thus it should reduce the octane value imho RichiH 18:04, 2 September 2006 (UTC)[reply]

If there are plastic parts or hoses which degrade, soften or dissolve in acetone but not in gasoline, you might be in for some expensive repairs. As an analogy, I had a 1970 GM engine which worked great until in the 1980's they started adding alcohol to gasoline. The alcohol ruined the plastic float in the carbureter and required replacement of the carb. And doesn't acetone react with copper? Gasoline is for burning in engines, alcohol is for drinking, and acetone is for removing nail polish. Edison 17:06, 1 September 2006 (UTC)[reply]

As Edison shows above, chemicals are used for specific things for a reason. I wish I could explain why acetone is used the way it is, but I've only experienced organic chem for 2 classes so far :/ --Russoc4 20:05, 1 September 2006 (UTC)[reply]

genetics

do all the somatic cells in our body have the same sequence of DNA?--hima 13:30, 1 September 2006 (UTC)

In theory they all should since they are all clones. In practice, however, mitosis does not copy with 100% accuracy so there are differences. Add Lyonization and DNA methylation to the mix, you have quite a few differences. InvictaHOG 13:57, 1 September 2006 (UTC)[reply]

Also, some people are chimeras, but that's rare. --Allen 03:55, 2 September 2006 (UTC)[reply]

Article in Dec 2000 Cleo

I am looking for an article you had in Dec 2000 Cleo titled FLEX by Sam Murphy. It was four pages long and was about exercises for deep abdominal muscles. If there is anyway you could forward me a copy or put it on your website I would be most grateful. Thank you Ruth Kelly, Ireland.

Wikipedia does not publish nor maintain archives of Cleo (magazine), but we have a stub article on it... Perhaps this should be moved to Humanities?Nimur 19:40, 1 September 2006 (UTC)[reply]

potentiometer

Q1 principle of potentiometer? Q2 why voltage decreases in the direction of electric field? (please explain in detail) thankyou.

A1 potentiometer / A2 voltage drop ---Sluzzelin 13:58, 1 September 2006 (UTC)[reply]

A2 Consider a line through an electric field, with three points on it, A, B, and C. The voltage at A is 2V, at B it is 1 V, and at C it is 0 V.

A-----------B---------C

If an object initially at rest, with a charge of +1 coulomb moves from A to C in an environment with no friction or other impediment, it will acquire kinetic energy of 2 joules by the time it gets to C. On the other hand, if the object starts at B, it will only have 1 joule of kinetic energy when it gets to C. So the voltage at any point in an electric field is a measure of how much energy a charged particle will acquire as it moves through an electric field, and the less of the field it moves through, the less energy it will acquire. --Gerry Ashton 16:32, 1 September 2006 (UTC)[reply]

mosquito

what does a mosquito have instead of blood is it hemolymph like all other insects?or anything else?--hima 13:56, 1 September 2006 (UTC)hima

Have a look at mosquito and hemolymph --Light current 14:24, 1 September 2006 (UTC)[reply]

Hemolymph redirects to blood or circulatory system. We don't have much of an article on it, just a few sentances in the appriate article. — [Mac Davis] (talk) (Desk|Help me improve)

Petrol additives

Is there anything that can be added to unleaded petrol to improve fuel consumption in a car with an engine management system? —Preceding unsigned comment added by Light current (talk • contribs)

I don't think so. It would be more productive trying to tweak the software I think.

In the UK you can add vegetable oil to your diesel fuel (or run pure veg oil) - veg oil is untaxed so it's cheaper than diesel and works just the same. You can smell cars running on veg oil as they drive past - not a myth at all. Illegal though. Rentwa 14:47, 1 September 2006 (UTC)[reply]

Vegoil as fuel is taxed in the UK now: see vegetable oil as fuel. Rmhermen 16:48, 1 September 2006 (UTC)[reply]

Motorists have always been liable to pay tax and duty on the fuels they put in their cars. There's nothing illegal about putting veg oil in your car - it's illegal not send a cheque to the chancellor when you do so, which most veg oil drivers don't. Veg oil for sale in the supermarket has no fuel duty or tax added to its price, or housewives would probably be complaining... Rentwa 17:40, 1 September 2006 (UTC)[reply]

In Germany, running on vegoil is not taxed and a more and more common option for diesel cars. Please note that you should consider installing a dual system with a large vegoil tank and a small diesel tank. The first and last 15 minutes of any trip should be done on diesel to prevent clogging of the pump etc. This is especially important in cold climate! RichiH 13:35, 3 September 2006 (UTC)[reply]

Most of the additives sold to mix in with your fuel and oil are modern-day snake oil, except in the relatively rare case where your fuel system is genuinely clogged. Subaru recommends the occasional use of an injector cleaner in the fuel of my car, but other cars I've owned have not done so.

One possibility is buying petrol with a partial ethanol blend; it's cheaper in some places because there's no taxes on the ethanol part. But the savings, if any, will be very small.

If you really want to save fuel, make sure you don't carry unnecessary items in the car, make sure your tires are kept inflated to the recommended pressures (or a little above, perhaps to what the manufacturer recommends for heavy loads), and drive smoothly and at sensible speeds. Beyond that, drive a more fuel-efficient car. -Robert Merkel 15:47, 1 September 2006 (UTC)[reply]

Could it be my EMS sensors not working correctly?--Light current 15:51, 1 September 2006 (UTC)[reply]

In your car I think the problem is less likely to be caused by hardware or software, and more likely to be something to do with the wetware. :D Only kidding :) . Rentwa 18:32, 1 September 2006 (UTC)[reply]

Well, additives do reduce gasoline consumption in that they burn themselves, providing some fuel. So, if you add a pint of fuel additive to a tank of fuel, you might reduce the fuel consumption by up to a pint. Thus, they aren't lying when they say their additive "reduces gasoline consumption", they are technically correct. Of course, the cost of the additive greatly exceeds the cost of the saved gasoline, that part they don't tell you. StuRat 00:49, 2 September 2006 (UTC)[reply]

World spin

Ive often wondered what originally gave rise to the rotation of the earth and what its rotational energy would be. Any one know?--Light current 15:12, 1 September 2006 (UTC)[reply]

I am guessing, but most of the planets rotate in the same direction the Sun does, right? So the theory is they arose from a gout of matter spouting from the sun which condensed into what we have today. They also rotate in the same direction they revolve around the Sun, too, right? 12.41.204.3

Not necessarily. The original nebula from which the Sun formed had angular momentum, and following the prevalent theory of planetary formation, the entire cloud was rotating (perhaps due to the supernova explosion that gave birth to the cloud to begin with), and the planets, as they coalesced by attracting all the objects within their gravitational field and colliding among themselves, maintained that angular momentum. Tito xd^(?!?) 17:02, 1 September 2006 (UTC)[reply]

After edit conflict:

As was discussed in a thread a few days ago, Venus and Uranus are the odd ones out when it comes to rotation. The rotational direction of the others makes sense to me in the way the coriolis effect works: material that moved from the outside of the accretion disk towards the inside to become part of the Earth went to a region with slower rotation, so the material that hit the part of the Earth that was pointing away from the Sun moved faster than the Earth and thus gave that side an extra impulse. Material that came from the other side ('from the Sun') was slower and thus slowed that side of the Earth down. DirkvdM 17:17, 1 September 2006 (UTC)[reply]

Calculating the rotational energy would require integration, which I'm not good at, so I'll just make an educated estimation. A kg at the equator moves at 40.000 km / 24 h and thus has an an impulse of 40.000.000 m / 80.000 s = 500 kg.m/s. The Earth weighs 6 x 10²⁴kg and assuming that the centre of mass of one side is at about half the radius the total rotational impulse would be 0,5 x 6 x 10²⁴ x 500 = 1500 x 10²⁴ kg.m/s. That's impulse, though, not energy. I'm not a physicist either. :) DirkvdM 17:25, 1 September 2006 (UTC)[reply]

Don't forget to include moons and rings when calculating the orbital angular momentum of a planetary system! Nimur 19:36, 1 September 2006 (UTC)[reply]

Moons and rings are typically insignificant in mass compared with the planet they orbit. Earth's moon is an exception, being quite large relative to Earth. Pluto, if you still consider it to be a planet, is also an exception, with it's biggest moon, Charon, being even larger relative to Pluto than our moon is to Earth. The mass of everything else in the solar system is also insignificant relative to the Sun. StuRat 20:44, 1 September 2006 (UTC)[reply]

Well early earth collided with a "roughly mars sized object" so wouldnt its spin be messed up this anyway? Philc _T^E_C^I 20:56, 1 September 2006 (UTC)[reply]

The Giant impact theory? Not necessarily. If the two bodies were rotating on similar planes, they would have a very similar angular momentum unit vector, so when the collision occured, the resulting body would still have the sum of the individual bodies' angular momentum, in a similar direction. Tito xd^(?!?) 06:10, 2 September 2006 (UTC)[reply]

I don't think similar planes would do it, they would have to be orbiting in pretty much exactly the same plane, or the off-center collision would tilt the two rotating objects. StuRat 10:32, 2 September 2006 (UTC)[reply]

Since they didnt collide core to core, and more of glanced, tearing the smaller in to 2 pieces, one of which then collapsed into the earth, the other settled into orbit after taking a large lump of crust with it. Aglancing hit would mean al of the momentum was transferred onto one side, so would it actually be possible for the spin to be undisturbed. Philc _T^E_C^I 18:58, 2 September 2006 (UTC)[reply]

The rotational kinetic energy is actually easy to calculate (treating the Earth as a sphere allows us to re-use others' integration!), and is even given in that article as an example. --Tardis 17:56, 6 September 2006 (UTC)[reply]

Zoosex

Can for example a cat become pregnant from human sperm and vice versa (a woman from horse)? --Brand спойт 16:55, 1 September 2006 (UTC)[reply]

'Can for example a cat become pregnant from human sperm ...' is there something you want to tell us? Rentwa 17:45, 1 September 2006 (UTC)[reply]

Unless they contain the same number of chromosomes, no. Tito xd^(?!?) 16:58, 1 September 2006 (UTC)[reply]

not entirely true -- as mentioned below, horses and donkeys can reproduce, even tho they have different chromosome numbers. if they have a different no of chromosomes, tho, their offspring will almost certainly be infertile --DakAD 07:23, 3 September 2006 (UTC)[reply]

Their offspring will always and without execption be infertile. RichiH 13:39, 3 September 2006 (UTC)[reply]

Oopsie, seems a ; instead of : in the identation makes text bold.. RichiH 14:26, 3 September 2006 (UTC)[reply]

No. Species must be very similar for such matters to take place (horse and donkey, for example). —D a niel (‽) 17:00, 1 September 2006 (UTC)[reply]

Also supposedly lion and tiger. What about primates? Gorilla/chimp/orangutan combinations? Horse/zebra? Edison 17:11, 1 September 2006 (UTC)[reply]

Species are defined as being able to interbreed, so if two animals are of different species, they can by definition not interbreed. Btw, if you ask about interbreeding primates, why not take a combination with humans to spice it up a bit? A humanzee? A humilla? With an Orang Utan the naming gets interresting because the word 'orang' is Indonesian for 'human' (and 'hutan' means forest, so it's a 'forest man'). DirkvdM 17:33, 1 September 2006 (UTC)[reply]

It's a little more complicated than that. Horses and donkeys are definitely different species, but they can produce offspring, and once in a great while even fertile offspring. Sometimes species are defined as being able to produce offspring that "breed true", whatever that means. I think it needs to be recognized that there is no completely precise biological definition of "species"; like any other level of taxonomy, there are arguable borderline cases. --Trovatore 17:37, 1 September 2006 (UTC)[reply]

If it is seperate genuses than no way, as far as I know. — [Mac Davis] (talk) (Desk|Help me improve)

For the record, the plural is "genera", à la generic vs. specific characteristics. Melchoir 18:13, 1 September 2006 (UTC)[reply]

Yes there are cross-genera and even cross-family hybrids. See hybrid, the article. Rmhermen 18:48, 1 September 2006 (UTC)[reply]

Two separate geniuses have indeed been known to reproduce. Edison 04:51, 2 September 2006 (UTC)[reply]

animal genera? --DakAD 07:23, 3 September 2006 (UTC)[reply]

I see a pattern emerging here. First, there was no precise definition of planet until last week (and it's still not fully accepted). Now, you're telling us there's not even a precise definition of species. Before we go any further, is there anything else the scientific world wishes to 'fess up about? JackofOz 12:28, 3 September 2006 (UTC)[reply]

To get back to the original question, rest assured, no, your cat is absolutely, positively, not pregnant with your love-child. Loomis 20:54, 3 September 2006 (UTC)[reply]

You mean love kitten!--Light current 20:56, 3 September 2006 (UTC)[reply]

Humans can't even make a chimpanzee or bonobo pregnant, so there's not very much to worry about. However, according to Greek mythology, the minotaur was born when a woman hid into a wooden cow to mate with a bull that she loved. bibliomaniac15 23:48, 5 September 2006 (UTC)[reply]

Citric Acid

Would diluted citric acid kill sperm?

Are we still talking about the cat? Rentwa 18:40, 1 September 2006 (UTC)[reply]

Ah, but aren't we all, on some level, talking about the cat? Melchoir 18:43, 1 September 2006 (UTC)[reply]

I think the cat is really going to dislike you if you introduce citric acid to the sitution. Weregerbil 18:55, 1 September 2006 (UTC)[reply]

Would diluted citric acid kill the cat? Until we dump the citric acid on the cat, he is both alive AND dead; we will determine an outcome by dumping acid on him. DO NOT TRY AT HOME Nimur 19:35, 1 September 2006 (UTC)[reply]

It probably wouldn't kill the cat, but I bet it would sting the pussy. Rentwa 00:01, 2 September 2006 (UTC)[reply]

Oooo it makes your eyes water just to think about it (2 points I think 8-))—Preceding unsigned comment added by Light current (talk • contribs)

This is a surprise to me, but Spermicide actually answers the question. Melchoir 18:44, 1 September 2006 (UTC)[reply]

Not talking about the cat (though funny placement. I have good timing.) Thanks!

Err...Part two; would citric acid kill a yeast infection?

Dammit, I can't look at that article. I'm not even going to link to it. Melchoir 19:58, 1 September 2006 (UTC)[reply]

Which article do you mean?--Light current 01:59, 2 September 2006 (UTC)[reply]

Why not try squeeezing your lemon to find out?--Light current 21:33, 1 September 2006 (UTC)[reply]

"Squeeze my lemon, till the juice runs down my legs". DirkvdM 09:19, 2 September 2006 (UTC)[reply]

Did you catch the yeast infection from the cat? You should probably see a doctor, or Vet..........Daniel.thorpe 11:08, 5 September 2006 (UTC)[reply]

Moon moons ?

Does any moon have it's own natural satellites ? I would expect they would, unless tidal forces from the planet would cause their orbits to be unstable.

If there are examples of moon moons, how about moon moon moons, etc. ? (Has the word lost all meaning yet ?) :-) StuRat 20:49, 1 September 2006 (UTC)[reply]

Wouldnt any moon moons be pulled out of their orbit when they get to close to the planet of the moon they are orbiting, as relative to their sizes, planets are alot closer to their moons, than the sun is to its.

Hmm... isn't that what happens at a Lagrange point? And it sounds a bit like something the L5 Society would like to know. Tito xd^(?!?) 20:57, 1 September 2006 (UTC)[reply]

Do you consider 3:2 orbital resonance to be a "moon"? (Earth's "second moon" is 3753 Cruithne, which is not really a moon but has a 1:1 resonance.) Then Pluto would be a moon of Neptune, and then Nix and Hydra are "moon moons". —AySz88 \^-^ 21:08, 1 September 2006 (UTC)[reply]

It would be extremely unlikely that any moon would have its own moons. Any such orbits would be extremely unstable with all the bodies as close together as they are in a solar system. Over larger distances it's certainly possible, although the bodies get a lot bigger. The Sun orbits the centre of the galaxy, the Earth orbits the Sun and the Moon orbits the Earth. Why this system works is probably best explained by the anthropic principle. An alternative explanation would take a very long time to give.

I think if you have too many generations of moons, you may end up with an ustable chaotic system that would eventually chause some of thes objects to coalesce.--Light current 14:51, 2 September 2006 (UTC)[reply]

What conditions would be needed to have a stable moon moon ? Perhaps a huge planet/failed star at an extreme distance (say 40 AU) from the main star could have a moon at an extreme distance from it (say 1 AU), and a moon moon around it that would be stable (being far enough away from gravitational tidal forces of the planet and star) ? StuRat 00:34, 2 September 2006 (UTC)[reply]

Although I don't know of any, I don't see why in theory moons can't have moons. After all, our moon has over the past half century had probably hundreds of "artificial satellites" orbitting it. Though these artificial satellites have generally, deliberately ended there missions by having their orbits decay, eventually crashing into the moon, surely there must be at least some space junk orbitting the moon at this time in an orbit with the potential to carry on indefinitely. This may be "space junk", but if it exists, in theory at least, it would seem to qualify as a "moon" orbitting the "moon". Loomis 04:24, 2 September 2006 (UTC)[reply]

Isn't that a matter of mass? An artificial satelite can do it, so why not a natural one? How this would be formed is a differnt matter. I don't think you would get such a moon from the same planetary accretion disk, so it would have to be caught. Probably the chances of that producing a stable orbit are very small, but in an immense Universe that's all you need. DirkvdM 09:28, 2 September 2006 (UTC)[reply]

In theory moons can have moons. The problem is that the orbits will (almost) certainly be unstable over long time periods due to the number of forces acting on them (they would certainly be unstable if they existed for an infinite time). It is possible (although highly unlikely) that (taking our moon as an example) our moon could trap a body to behave as its own satellite, but it would only stay there for a very short time and, if it did happen, we weren't around to see it. Artificial satellites have the same problem of stability. The articles on chaos and the n-body problem should be relevant to this (assuming they're well written).

Moons can have artificial satellites, such as the Apollo Command/Service Module during the manned moon missions. Nimur 13:03, 2 September 2006 (UTC)[reply]

Just to qualify everything... in the approximation that the moon's orbit is circular, then you can prove mathematically that certain orbits around the moon are stable, since they are completely encircled by the zero-velocity curves of their Jacobi integral. Such protective curves go all the way out to the nearest Lagrange points. So you don't have to worry about the planet pulling the particle away from the moon.

What you do have to worry about is the possibility that, if you wait long enough, the particle might crash into the moon. There is no mathematical barrier to such a crash, as there is in the two-body problem (the centrifugal barrier). In some sense the real question is, how long should it take for such a crash to occur? And I seriously doubt there's a known analytic answer to that one; you'd have to break out a numerical simulation, plug in your desired mass ratio and moon radius, and see. Melchoir 17:23, 2 September 2006 (UTC)[reply]

I could always moon the Moon. Would that help? Clarityfiend 04:37, 3 September 2006 (UTC)[reply]

And then let someone else drop their pants and run in circles around you. Problem solved. QEI (quod erat inquisitum). DirkvdM 05:36, 3 September 2006 (UTC)[reply]

Private Hospitals in Altanta, Georgia in existence 1967

Trying to locate nurse who worked in expensive private hospital, Coronary Care Division in Atlanta, Ga. in 1967. Hospital could place instrument for heart (cost $2,000) on arm in case of heart failure. Feel this fairly new concept at time. Hospital's name wanted. Help,please!

How about Emory University hospital? InvictaHOG 21:24, 1 September 2006 (UTC)[reply]

Free software to make contour maps from spot heights?

Is there any please? There is a pay-for program called Surfer, but it costs over $500. 62.253.44.32 23:36, 1 September 2006 (UTC)[reply]

Given an XY grid of points, where the Z coord is given for each, it seems like quite a simple program could create a contour map. Given points not on a grid, it would be a bit trickier. Also note that a general 3D CAD system could do this, by running a surface thru a point cloud, then intersecting that surface with planes parallel to the XY plane. StuRat 00:23, 2 September 2006 (UTC)[reply]

Wouldnt it be grossly inaccurate due to the fact that the ground is not flat planes between spotheights, something that a program designed for this would probably take into account. Philc _T^E_C^I 00:33, 2 September 2006 (UTC)[reply]

The simplest program could just do a linear interpolation between grid points, to find contour line/grid line intersection points, then draw straight lines between those. For example, given grid point elevations of 4, 6, 7, 1, 2, and 4, a contour line could be drawn at an elevation of 5:

4 . . . . . * . . . . . 6 . . . . . . . . . . . 7
. . . . . . . . * . . . . . . . . . . . . . . . .
. . . . . . . . . . * . . . . . . . . . . . . . .
. . . . . . . . . . . . * . . . . . . . . . . . .
. . . . . . . . . . . . . . * . . . . . . . . . .
. . . . . . . . . . . . . . . . * . . . . . . . .
. . . . . . . . . . . . . . . . . . * . . . . . .
. . . . . . . . . . . . . . . . . . . . . * . . .
. . . . . . . . . . . . . . . . . . . . . . . . *
. . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . 
1 . . . . . . . . . . . 2 . . . . . . . . . . . 4

StuRat 03:27, 2 September 2006 (UTC)[reply]

R is free and can make contour maps, I'm pretty sure. I don't know fancy the graphics get, though. --Allen 03:46, 2 September 2006 (UTC)[reply]

Gnuplot can produce contour plots. – b_jonas 10:42, 2 September 2006 (UTC) (Update: I mean if the samples form a grid. – b_jonas 10:43, 2 September 2006 (UTC))[reply]

Thanks, but unfortunately my data does not form a grid.

If the data is not already in a grid, the first task of any program would be to establish a grid, a process called tesselation. Then you could do the same linear approximation discussed previously, from there. However, if you only have a low number of sample points, the resulting contour plot will be highly inaccurate. StuRat 03:06, 3 September 2006 (UTC)[reply]

I believe that Yorick programming language can produce contours from data on irregular meshes. But just trying to understand that part of its documentation makes my head hurt. -- The Photon 04:51, 4 September 2006 (UTC)[reply]

Hmmmn, I wonder if the best method would be to assume that the height at any point would be the weighted average of all the spot heights, where the weights are in inverse proportion to the distance (or perhaps distance squared or some other weighting scheme)?

If I were to implement this myself rather than use somebody elses software, then the question changes to: Whats the best way to interpolate heights from know spot heights? Thanks again.

I think you've got a good idea for how to do it. I do see one problem, though, you could never get a height above the max input height or below the min input height. Consider these data points:

Z *                       *
^   *                   *  
|      *             *
|              
+---------------------------> X

The result of the extrapolation should provide this point:

Z *                       *
^   *                   *  
|      *             *
|             * 
+---------------------------> X

StuRat 11:58, 3 September 2006 (UTC)[reply]

Yes. This reminds me of kriging or splines, although I've no idea if either free software is available or how I could implement these myself.

Sorry to be pedantic, but shouldnt you have said interpolation?--Light current 20:59, 3 September 2006 (UTC)[reply]

Well, interpolation would be correct if I only meant to describe filling in between data points, but I also meant filling in beyond the end of the data points, so extrapolation covers both cases:

Z *                  
^   *                  
|      *             
|             * 
+---------------> X

StuRat 08:40, 4 September 2006 (UTC)[reply]

You might be interested in checking these discussions http://stackoverflow.com/questions/11449214/creating-grid-and-interpolating-x-y-z-for-contour-plot-sagemath http://in.mathworks.com/help/matlab/math/interpolating-scattered-data.html http://stackoverflow.com/questions/19339296/plotting-contours-on-an-irregular-grid Shyamal PS: silly me to edit on an old archive page that I had accidentally opened!!! (talk) 08:53, 30 January 2015 (UTC)[reply]

September 2

Self CPR

I'm taking a final exam for an online class and one of the questions I have to answer is whether self CPR is fact or fiction.

Perhaps you could think about this for a few seconds. BenC7 01:58, 2 September 2006 (UTC)[reply]

If you are unconcious how would you do it?--Light current 02:03, 2 September 2006 (UTC)[reply]

There is a procedure to help yourself when you are choking where you hold your fists just south of your thorax and run into a wall with your head held back (I Canada you usually learn that as an aside on your way to becoming a life-guard). Maybe something similar could work for when your heart stops, though I think the chance of your heart stopping and you knowing while being concious are pretty much zero. Then there's the fact that manual CPR usually only works after repeated applications, which means you'd be running into the wall a lot. freshofftheufo ΓΛĿЌ 06:27, 2 September 2006 (UTC)[reply]

...That is a procedure in Canada? Can I PLEASE see it on tape or something? If I didn't suspect it would hurt like a bum, I'd try it out. Sounds difficult to run onto things like that. Henning 08:26, 2 September 2006 (UTC)[reply]

Haha, I've never actually seen it done. My instructor just explained how it could be done if you were ever caught by yourself with a chicken bone stuck in your throat. freshofftheufo ΓΛĿЌ 15:57, 2 September 2006 (UTC)[reply]

Fiction. If you have no pulse and no respirations, you are unconscious and unable to do CPR. InvictaHOG 09:32, 2 September 2006 (UTC)[reply]

Which leads me to think, are you sure it's "self CPR" and not "self Heimlich-maneuver" or something? Just a thought. CptJoker 01:22, 3 September 2006 (UTC)[reply]

5 or 10 years ago there was a story which made the rounds of print media and internet that if one suddenly realized his heart had stopped, he could do self cpr by coughing vigorously, and get enough blood to circulate to maintain consciousness long enough to summon help or dial 911. A while letaer Red Crosss officials denied it was true. Could one realize the heart had stopped and still have consciousness for a bit? Why not? Edison 20:31, 2 September 2006 (UTC)[reply]

That's not to be done if your heart stops, it's taught in MedSchool if you go into VF. If you cough, at least some blood gets moved around cos the valves keep doin' what they're doin' despite zero cardiac output from ventricles. ≈Eh-Steve 21:02, 2 September 2006 (UTC)

Viral Marketing

I'm rather worried by the note at the bottom of the Factotum article. I wandered through the history, and apparently on 3 August, an anonymous person added what looked like a full-page advertisement for the film. On 23 August, another anonymous person removed it, leaving a rather cryptic note with a link to the viral marketing article. To be honest, I've been wondering for awhile just how much people could potentially take advantage of Wikipedia for monetary gain. Does it sound to you like that's what was happening? Black Carrot 02:16, 2 September 2006 (UTC)[reply]

Yes, it's absolutely a problem with a medium like Wikipedia. A simple example would be all the neologisms that people try to get added, thus increasing awareness about the unknown word in the hopes that somebody will actually get tricked into using it in an AOL chat session. Most of those get caught pretty easily, but I imagine it's much more difficult to pick things like that out of articles with corporate connections so who knows how much if it actually gets through. freshofftheufo ΓΛĿЌ 06:33, 2 September 2006 (UTC)[reply]

When was redial invented?

I've been searching all over the Internet and I can't find the date that redial was invented. What I really want to know is, would telephones in 1990 have automatic redial buttons, and, if not, what would they have? Please help. 88.105.159.129 10:12, 2 September 2006 (UTC)[reply]

I would guess that was available on the first touch-tone phones. Dial phones did not normally have that feature. StuRat 10:24, 2 September 2006 (UTC)[reply]

True, but they had a line to the operator, who could probably redial for you--71.247.243.173 13:44, 2 September 2006 (UTC)[reply]

That would be a serious pain in the neck in comparison with just a simple button. --Fastfission 15:46, 2 September 2006 (UTC)[reply]

Ah, so it's been around since the sixties then. Thank you! 88.105.159.129 10:36, 2 September 2006 (UTC)[reply]

They've definitely been around since 1990. I can remember them from the even the very old (and crummy) phones from that time. --Fastfission 15:46, 2 September 2006 (UTC)[reply]

I have seen rotary phones with a redial function before. It's almost rediculously complex, and it seemed to take a while to actually dial the number (it of course has to mechanically spin the dial). I can't say when it was actually invented though, or if the touch-tone version came first. freshofftheufo ΓΛĿЌ 15:55, 2 September 2006 (UTC)[reply]

Yea, I see no reason why it wouldn't be possible on a rotary phone, but it does seem like an ugly bit of machinery would have been required, making it easier to just manually redial. An analog audio tape of the clicks could also be recorded then played back. A hybrid would also have been briefly possible, where the clicks were captured digitally and played back electronically. Of course, once that technology was available, why not just upgrade to a touch-tone phone, instead ? StuRat 22:13, 2 September 2006 (UTC)[reply]

Have you ever tried redial on a dual-function phone? The kind with a tone switch, that can send rotary style signals if tone-dial doesn't work in your area (or at least I assume that's why). If it's set on rotary mode, and you hit redial, you can hear it clicking away old-skool, though I've never been interested enough to figure out how it was doing it (I've had at least 1 phone from the 80s with that capability). There's actually a manual rotary redialer featured in The Matrix. Guess they never thought of using an analog recording either. freshofftheufo ΓΛĿЌ 10:22, 3 September 2006 (UTC)[reply]

You can't just tape record the sound of the clicks. Pulse dialing phones operate by momentarily opening the telephone circuit, blocking all current. The click you hear is just a side-effect of that (and, in fact, the dial has contacts that entirely or mostly mute the receiver while the dial is "off normal" (turned away from the normal position). And yes, some electronic dial-pulse phones did have "redial" capability. I had one that I'd guess dated from ca. 1980 or '85.

And then there were the card-dialing phones. Very odd, these devices (which dated from the '60s) contained a cute little card reader. By punching holes in plastic cards, you could program each card to contain one phone number. Then, by popping a person's card into the reader and pressing a single button, the phone read the card and dial-pulsed out the number, giving you the 1960s equivalent of speed-dial.

Atlant 01:15, 7 September 2006 (UTC)[reply]

Karl von Goebel

Why is Karl von Goebel sometimes known as Karl Ritter von Goebel and others as Karl Immanuel Eberhard von Goebel ? — Dunc|☺ 11:02, 2 September 2006 (UTC)[reply]

Check out Ritter. It is a title of nobility that can be added or not according to the author's preferences. Same goes for Karl von Goebel vs Karl Immanuel Eberhard von Goebel; it depends on context, space, and preferences. George W. Bush is sometimes referred to as George Bush or George Walker Bush or Dubya and Brian Eno is sometimes referred to as Brian Peter George St. Jean le Baptiste de la Salle Eno :). ---Sluzzelin 11:34, 2 September 2006 (UTC)[reply]

refrigerator vs. environment

Can a refrigerator operate successfully in an unheated garage in winter where the temperature falls below freezing?

Why not? Don't most firdges have an internal thermostat? in which case, it would read the temperature as below 0^oC and woudln't need to do anything (: 71.247.243.173 13:43, 2 September 2006 (UTC)[reply]

if contents of a refrigerator spoil when power is cut off when the environment is warm ...obviously the fridge is not 100% insulated....therefore, if the fridge senses the outside temp. as freezing and doesn't do anything...wouldnt the contents eventually freeze? I am referring to a fridge...not a freezer.

There's no such thing as below zero ;). My guess would be that unless you had a fridge which had the ability to warm, then prolonged exposure to below zero would cause the contents to freeze. Hell, my fridge freezes everything in sight, and it has never seen temps below zero! --liquidGhoul 14:04, 2 September 2006 (UTC)[reply]

It gets colder than -20 C in the winter where I'm from, and the answer is a pretty obvious yes, if you go away on a ski trip for a few days and turn off all the power, all of the food in your fridge will freeze. freshofftheufo ΓΛĿЌ 15:51, 2 September 2006 (UTC)[reply]

Soft drink machines are commonly outdoors in states where it gets to -20 F in the winter. I expect they have internal heaters to keep the contents from freezing. In an ordinary refrigerator, in an unheated garage, if the air got below 32 F for an extended perion the contents would certainly freeze. A little ingenuity could install an auxiliary thermostat inside to turn on the light bulb or a light bulb when the temperature in the fridge got down to 32 f. The deadband would have to be precise, so the light/heater would go off at a temperature below the one where the cooling unit went on, and contrariwise. For instance, the cooler goes on at a rise to 40 degrees and off at a drop to 37 degrees. The light bulb or heater goes on at a drop to 33 degrees and off at a rise to 35 degrees. See the problem? You could wind up with the heater on fighting the cooler. Edison 20:39, 2 September 2006 (UTC)[reply]

I expect they have internal heaters to keep the contents from freezing.

They do.

Atlant 01:03, 7 September 2006 (UTC)[reply]

If you had a small electric space heater, with a thermostat that goes down to freezing, you could put that in the fridge when it gets cold. Do they sell such heaters to keep pipes from freezing ? StuRat 22:00, 2 September 2006 (UTC)[reply]

I actually asked this question a few months ago. My suspicion, though I may be wrong, is that you guys may be off on the wrong track. From what I understand, refrigeration (as well as A/C) works by sucking in ambient air and passing it over coils of compressed freon. The freon coils are kept at a certain temperature (depending on the level at which the freon is compressed, the more compression, the colder). For a freezer, say, the freon is compressed to a point where it is below freezing, and air is then passed over them, causing below freezing temperature air to pass into the freezer, and thus causing the temperature of the air in the freezer to be below freezing temperature. For above freezing temperature refrigeration, the freon is less compressed, to a point where it is, say 1°C or 2°C. Ambient air is then blown over the coils, and the fridge temperature is lowered to just above freezing. NOW, when the temperature of the ambient air dips below freezing, the same thing happens. The below freezing temperature ambient air is sucked into the unit, blown over slightly above freezing temperature freon coils (1°C or 2°C), and thus, in a weird sort of way, the freezing ambient air is "heated up" to above freezing. I know it sounds weird, but when you think about it it makes sense. Heat doesn't always equal "fire" or "warmth" as we understand it. Think of it this way, throw a regular block of ice into a vat of liquid oxygen, and the ice cube will actually raise the temperature of the liquid oxygen. Throw a big enough block freezing cold ice in, and you may actually be able to heat up the liquid oxygen to its "boiling point" at which point it'll "boil" into oxygen gas. Of course, this is just one big guess, I could be wrong. Loomis 20:43, 3 September 2006 (UTC)[reply]

Seminar report

We have a weekly semianr to be given on any of the technological advancement aorund us. I have decided to give a seminar on the RADAR JAMMERS.

I was looking forward for some good materials so as to produce a good report. I have found a few but would like to get into the core of the subject for self interest.

Would be looking forward for help from any of u.. Thanks Saket--220.227.48.17 13:36, 2 September 2006 (UTC)[reply]

Doesn't it make sense for you to choose to give a seminar about something on which you are knowledgable, rather than just relying on the nice people at Wikipedia? —D a niel (‽)

electronic attack. Xcomradex 15:30, 2 September 2006 (UTC)[reply]

Memory Metal for Cars?

How strong are memory metals? Could you theoretically build the outside of a car from one, and then, after an accident heat it up and have it regain its former shape?

Thanks, —D a niel (‽) 14:43, 2 September 2006 (UTC)[reply]

I know this but I cant remember! I need to shape up I know 8-)--Light current 15:51, 2 September 2006 (UTC)[reply]

I don't understand why it's so expensive to replace a car body panel. They should be dirt cheap, as they're stamped by the thousand. Perhaps we need a change in the structure of auto sales, where the car company leases cars for a few months at a time. Then, when they get a dented car back, they would have an incentive to replace the body panel cheaply, so it could be released. At present, they don't seem to have any incentive to make repairs inexpensive, as that just prevents people from buying new cars. StuRat 21:53, 2 September 2006 (UTC)[reply]

A great question! BenC7 04:09, 3 September 2006 (UTC)[reply]

The price could have someting to do with labour intensity. The panel seems expensive compared to the car, but it's really the cars that are dirt cheap for the sort of product you get, due to mass production. Repair work isn't mass production, so it's relatively expensive. Maybe if you could buy the panel and then replace it yourself. But then there would have to be a distribution network for loose parts, and the per piece price would probably far exceed the production cost. Your solution would solve the latter problem, but not the former. DirkvdM 05:59, 3 September 2006 (UTC)[reply]

The existing distribution channels for dealer parts could also be used for car body panels. Each dealer could stock several of each body panel for each car model. StuRat 11:47, 3 September 2006 (UTC)[reply]

There is also the possibility of plastic car exteriors, which I believe would be easier to 'de-dent' and would also be lighter and therefore more fuel efficient. This already exists, but my guess it isn't popular because plastic can't be made as shiny as metal. DirkvdM 06:01, 3 September 2006 (UTC)[reply]

Although (at least for most cars) it's not the metal that's doing the shining, it's the half centimeter coat of crap on top of it that does. You may be partly right, though, that it seems to be more difficult to "buff" plastics smooth, which could cause problems before you coat them with the shiny stuff. freshofftheufo ΓΛĿЌ 10:14, 3 September 2006 (UTC)[reply]

Plastic body panels are actually significantly more expensive than sheet metal. They have the advantage of being lighter, but aren't strong enough for a unibody design, requiring a frame. The tend to crack when damaged, not dent, which makes them more difficult to repair. For these reasons, they tend to only be used on expensive sports cars, like the Chevrolet Corvette. StuRat 11:42, 3 September 2006 (UTC)[reply]

Special relativity

So, I've been reading into Photon, Special Relativity and more, and I have come to be frustrated, very at that, at not understanding the topic.

I realize very well that there is a particle-wave duality to photons, it's their speed I can't understand. If I travel on a pimped up spacecraft with neon lights all over, and overtake another spacecraft, I will measure the speed of HIS light as C, even though I am travelling at +V away from him and his light?

Oh, and I have a second question, way better! Is there any book like... Relativity/Quantum dynamics For Dummies, which actually explains everything? Everything with a capital E, that is polarization, QED, string theory, t... everything? Many thanks in advance. 81.93.102.35 14:59, 2 September 2006 (UTC)[reply]

(I am not qualified to answer, don't get annoyed at me) As far as I know, you are right. Whatever speed you are traveling towards/away from each other, you will still see the speed of light in a vacuum at the same. This, I think, arises from some weird curvature of spacetime. —D a niel (‽) 15:22, 2 September 2006 (UTC)[reply]

THe way I tend to think of it is that light can only travel at one speed (in vacuum). THis speed cannot be changed as it is a function of the fundamental properties of space. So, whenever you try to measure the speed, you always get the same answer. What you will see, however, is a red shift if you are travelling away from the light source and a blue shift if travelling towards it. Is this helpful?--Light current 15:40, 2 September 2006 (UTC)[reply]

Though the "...for Dummies" franchise doesn't seem to have given it a shot yet, this google search might help you find the same sort of introductions. freshofftheufo ΓΛĿЌ 15:48, 2 September 2006 (UTC)[reply]

List of ...for Dummies books does mention Einstein for Dummies! Until you get the book you can also try more googling, the first hit looks like something I'm going to go and read right now. Weregerbil 16:07, 2 September 2006 (UTC)[reply]

For future reference: Most of the parameters in a Google URL are unnecessary (and possibly undesirable for a user whose cookie has unusual preferences); all you really need is the "q=". Weregerbil gets it right. —Tamfang 18:26, 2 September 2006 (UTC)[reply]

Yes, I noticed that and I was wondering what effect the "firefox" parameter generated from my browser would have on non-firefox users. I was just being lazy anyways, I'll make my links shorter in future! freshofftheufo ΓΛĿЌ 10:09, 3 September 2006 (UTC)[reply]

The Road to Reality by Roger Penrose is your best bet for a book that explains everything. Light current's comment that the speed of light cannot change might not be entirely accurate. There is evidence that the speed of light was lower in the past.

'Moving' source, 'stationary' observer

Look at it this way. Assume you are 'stationary', and something is receding from you shining its light at you. When the light on the distant object leaves the lamp, the light doesnt know that the lamp is travelling backwards at high velocity. All it knows is that it has been launched into space and is therfore compelled to travel at the universal velocity 'c'. When you measure its spedd you find its 'c' also. Any clearer?--Light current 15:49, 2 September 2006 (UTC)[reply]

'Stationary' source, 'moving' observer

Essentially the same as above. THe source transmits the light at 'c'. Although you are moving backwards at high velocity, the light doesnt know this and doesnt care. When it reaches you, red shifted, you still measure its velocity as 'c'--Light current 16:16, 2 September 2006 (UTC)[reply]

An easier answer (or so I hope)

Ok, you're watching another spaceship full of neon lights and you're observing it's light. You're travelling away from the other ship with a velocity of V or something of the like, something pretty fast. The other ship will fall behind you pretty fast. But if you phone the guys in the ship, they'll tell you: "We aren't moving, it's you that's going away." Well, that's just a different point of view, you see? Nothing special. Velocities just seem to be different when you're moving.

Except the one of light. The guys in the other space ship aren't moving (or so they think), so when they observe their neon lamps, they'll see light coming out with a velocity of c. When you are observing this same light being in the other ship, you'll see the same velocity relative to your own position. That may seem weird – you'd think it should be c+V or c-V or something of the like. But it doesn't work that way.

To relate your observation with their observation, you need Lorentz transformation. This means that space and time are related to each other in a way which is slightly more complicated than how you'd think they are. Velocity being space divided by time, it gets quite more complicated than c+V. But the result is just c.

Hopefully this helps. David 16:42, 2 September 2006 (UTC)[reply]

But surely the Lorenz transformation is a consequence of the invariance of the speed of light, and not the other way round? So the answer should be able to be given without bringing in Lorenz? 8-|--Light current 17:55, 2 September 2006 (UTC)[reply]

Thank you for clearing this up for me. I am in the process of reading that -- for Dummies-thing, it should work wonders. :) 81.93.102.35 18:10, 2 September 2006 (UTC)[reply]

Good page: Velocity_addition_formula--Light current 18:11, 2 September 2006 (UTC)[reply]

I know that according to the Michaelson/Morely experiment, there isn't any detectable change of speed of light in any direction, so there is no basis for an ether to exist. Still, have anyone tried accelerating something in vacuum? I don't know how realistic it is to assume that this can make any difference - I just wondered if it is certain that nothing spends more time or energy accelerating into one direction than into another. 81.93.102.35 19:27, 2 September 2006 (UTC)[reply]

Try The Elegant Universe by Brian Green. It starts with a humorous discussion of classical physics including relativity and progresses through quantum and finally string theory. He does not use any math so its a good book for light reading

129.174.194.48 18:01, 6 September 2006 (UTC)[reply]

Infinitly improbable events in infinite time

In an infinate amount of time, the probability of any event happening which has a probability not equal to zero is 1. So in infinite time every event even with a miniscule probability of say the inverse of a googel to the power of a googel, will definitely happen.

So even after I'm dead, by random chance something resembling my brain with the same thoughts and memories as I have now must eventually come into existence, not only once but many times. And I could also have the same kind of body, the same kind of society even. In other words I (and you) should be resaurected (sp?) many times, if the universe lasts an infinite length of time.

Can anyone point out a logical flaw in the above argument please? For example, will the universe last an infinite amount of time?

The universe (as we know it Jim) will not last an infinite time.--Light current 17:57, 2 September 2006 (UTC)[reply]

Although assuming our universe could last for an infinate time, i don't see any flaws in your argument. Benbread 17:58, 2 September 2006 (UTC)[reply]

In case anyone hasn't seen it: Kolmogorov's zero-one law. Melchoir 18:03, 2 September 2006 (UTC)[reply]

Many events (as humans perceive them) that do occur do not simply have miniscule probablity, they actually have probability of exactly 0. If the probability of an event is 0, then even given infinite time, then you might still observe that it happens never, only once, or many times. Consider a dart board and a dart. The dart board has some finite area. The dart has a much smaller, but still finite cross-section; however one can think about the center point of the dart: some mathematical point that defines the true center of where the dart strikes. Such a point has no area, being just a point. Throw the dart at the board and you know that some point will be selected in this way, but there are an infinite number of choices and each time you select only one center point of the dart. Hence the probability of selecting any particular point is 1/infinity which is exactly equal to 0. And yet you can perform the action and know each time with certainty that some point will be selected. Further, an event with a probability of 1/infinity, given an infinite number of trials, need not be expected to occur, because infinities come in different degrees, countable and uncountable. By definition any repetitive action performed an infinite number of times belong to the countable class of inifinities because you can enumerate each trial (1, 2, 3, 4, etc.). However, it can be proven that you could never enumerate all the points on a dart board, no matter how clever your scheme might be, there are simply vastly more than could ever be described by the set of all numbers 1, 2, 3... This is non-intuitive, I know, but in many situations there are simply more possible outcomes then one could possibly precisely enumerate, even given infinite time to do so. I supsect that most of what occurs, from the effects of a single storm to the evolution of the human race, are like throwing darts at a board. A particular event occurs from an infinitely rich set of possibly variation, but each possibility had an intrinsic probability of zero. If that is the case, then the probability of you, me, or the human race ever having occurred is zero and even given infinite time should not be expected to recur. Dragons flight 18:37, 2 September 2006 (UTC)[reply]

Dragons flight chose his words carefully, I want to point it out. If that is the case, then the probability of you, me, or the human race ever having occurred is zero and even given infinite time should not be expected to recur. That's, of course, not to say that it couldn't recur, just it isn't expected. Probabilities become very hard to understand intuitively when the number of trials is infinite. So, for any event with probability zero, it could happen any finite number of times in an infinite number of trials. With respect to your question if you assign the event that someone again has exactly the same thoughts as you a positive (non-zero) probability, then the probability it occurs again given an infinite number of trials, is 1.(*) However, if such an event has probability 0, given an infinite number of trials it might happen again, but it need not. (*: This is so long as each individual trial is independent) --best, kevin [kzollman][talk] 20:51, 2 September 2006 (UTC)[reply]

It is probably theoretically possible for something to have, say 1/4 probability of ever happening given infinite time (if I have this right). Imagine that, starting now, for some x amount of time, an event has a 1/5 probability of happening within that time. After that x amount of time, then for the next x amount of time, it has a 1/25 probability of happening. Then it has a 1/125 chance, then 1/625, etc. This goes on infinitely. The sum of all those is not one (or infinity) but 1/4 (see geometric series - scroll down that page) - not one or zero.

(I know the numbers don't sum up that way - the 1/25 ends up being 1/25 of the remaining slice, not 1/25 of the total slice - but explaining all that would detract too much from the point.) —AySz88 \^-^ 18:58, 2 September 2006 (UTC)[reply]

You have to remember that not all possible paths lead to all possible outcomes, when sonthings happens in the universe, it always cuts out the possibility of a an infinite number of alternative possibilities from ever happening. So basically, if the human race became extinct tomorrow, even if the universe existed for eternity, the possibility of someone exactly the same as you having the same thoughts as you is 0. Philc _T^E_C^I 19:32, 2 September 2006 (UTC)[reply]

Schroedinger's cat?--Light current 20:19, 2 September 2006 (UTC)[reply]

I'm afraid I don't see how this is related. --best, kevin [kzollman][talk] 20:51, 2 September 2006 (UTC)[reply]

As a bit of nit-picking, there is no such thing as "infinitely improbable" in the standard real number system. Something either has probability 0 or a positive probability. In order to have "infinitely improbable" one must introduce infinitesimals which results in a different theory of probability than is standardly used. --best, kevin [kzollman][talk] 20:51, 2 September 2006 (UTC)[reply]

See Infinite_monkey_theorem for an example of a finite, but highly improbable, event that would occur, given an infinite number of trials. StuRat 21:33, 2 September 2006 (UTC)[reply]

What do you think we're doing here?9-)--Light current 21:36, 2 September 2006 (UTC)[reply]

Except that we're not nearly as intelligent as the monkeys. :-) StuRat 21:42, 2 September 2006 (UTC)[reply]

Yeah, they got it made eating bananas, screwing round all day.... Hey hang on a minute- sounds familiar!--Light current 23:33, 2 September 2006 (UTC)[reply]

The formation of life on Earth may be similar. That is, it may be a highly improbably event, but, given all the planets and moons around all the stars, in all the galaxies in the universe, even highly improbable events become quite likely, somewhere. Then the not-too-bright say "but what was the chance it would have happened on the planet where we live ?". Well, the chance that life had evolved on any planet where life currently exists is actually quite good. StuRat 21:42, 2 September 2006 (UTC)[reply]

The flaw in the argument is that Kolmogorov et al are applying ideas from Pure Maths to Applied Maths (and then to Real Life). Things tending to particular limits as other things tend to infinity only means something in some very specific Pure Maths situations - to apply these processes to Applied Maths which is talking about real life is silly. Thats the flaw.

And since we're talking about real life I can postulate that the monkeys instead produce an infinite amount of garbage, or the atoms will come to resemble a donkey's thing, and you can't point to any real life cause which will necessitate that they do otherwise. Rentwa 22:31, 2 September 2006 (UTC)[reply]

What is zero multiplied by infinity? If you can do this, you have the answer.--Light current 22:35, 2 September 2006 (UTC)[reply]

Not defined by arithmetic, zero if calculated according to limits. Rentwa 22:40, 2 September 2006 (UTC)[reply]

It could be anything, calculated according to limits. For instance, lim(x->0) x(1/x)=1, x(2/x)=2, x²(1/x)=inf etc. If I may, though, I see some things that don't make sense to me. First, what does it mean to say that an event, like someone with a particular genetic code being born perhaps, has a particular "probability"? Or sentient life springing up, or whatever. The universe, above the quantum level, is as predetermined as clockwork. It's not a matter of manipulating random variables to get the answer, it's a matter of manipulating very very definite equations of physical motion. For instance, let's say we find the "probability" of a 2kg mass being pushed with 1N of force for 1s, but inexplicably gaining several thousand m/s of velocity. This would have a probability zero. Hitting a theoretical point with a theoretical dart has a probability "almost zero", meaning it could conceivably happen but almost certainly won't any time soon, but this just plain won't happen, ever. Am I right? So, it's not a question of whether a universe filled with random static could ever clear up for a moment into a universe with human life, it's a question of whether this universe, given its starting conditions and laws, will ever do so. Which it probably won't ever again, if the heat death theory is to be believed. The only thing that brings randomness into it is Schrodinger's cat, as someone earlier said, which is a demonstration of the link between the alleged pure randomness of the quantum world and normal events. Even given that, though, I doubt the question changes much.

BTW, something that crossed my mind, rereading the original question - If someone with your thoughts and memories were to show up later, given the strong link between thoughts and the reality that made them, that would suggest that the entire universe was on some sort of periodic cycle, wouldn't it? If the same things happened again, they would surely lead to the same results again, and therefore back to themselves again, ad infinitum. Only a universe where cause and effect weren't so closely linked, as in the imaginary random universe you're working with, could that not be the case. Black Carrot 23:15, 2 September 2006 (UTC)[reply]

Given multiplication of m by n is defined as adding n lots of m, 0 times infinity is the sum 0 + 0 +...+ 0 = 0 as the number of 0's tends to infinity, and it's trivial to prove lim = 0.

I've no idea what you're talking about :) . But you write very nicely. :) Very cool red sig btw. Rentwa 23:35, 2 September 2006 (UTC)[reply]

~~Are you familiar with the idea of a limit? Basically, it says that given a mathematical statement, we can get an idea how it behaves in a particular area by looking nearby.~~(Edit:Sorry, I just noticed you're the same guy as before.) The sum of an infinite amount of nothing certainly is nothing (stated I believe as

\lim _{x\to \infty }\sum _{a=1}^{x}0=0

or as 0+0+...+0=0 or as

\lim _{x\to \infty }0x=0

). It'll certainly never get bigger. However, take the function f(x)=x(1/x), which for x=1/5 for instance means (1/5 + 1/5 + 1/5 + 1/5 + 1/5) or (1/5)5. What does f(0)=0(1/0) mean? Well, at every point except x=0, this simplifies to f(x)=1, which suggests that f(0)=1 as well. But, on the other hand, g(x)=1/x gets arbitrarily large (as big as you want, then bigger) as x gets closer to 0, so g(0)=infinity, so f(0)=0(infinity). So, in two slightly different interpretations of 0 times infinity, it's reasonable to arrive at two very different answers, which is why arithmetic doesn't touch it. And thank you. Black Carrot 04:12, 3 September 2006 (UTC)[reply]

No, the axioms of arithmetic don't touch it because they only mention finite numbers (one or any of its successors). I can tell you're the same guy because of that cool red sig - and you write formulae very nicely too!

Your point about 0(1/0) I'm afraid isn't correct, 1/0 is not defined by arithmetic (just like arithmetic not defining operations with non-finite numbers) and therefore not part of functional analysis in general (isn't it wonderful, btw, that from an axiomatic point of view Analysis is hardly any bigger than Arithmetic?), although it is a neat un-rigorous way of showing zero times infinity is one. You could possibly make a more rigorous argument calling the point x = 0 a singularity.

The point to note is that you can use apparently sound logical ideas to get lots of different answers, which is why Pure Mathematicians devised analysis - so there was one realm of human thought at least that was bollocks free - which is why people are able to talk nonsense when they take sound ideas about limits and apply them to real events and end up with a monkey writing Hamlet. Rentwa 11:54, 3 September 2006 (UTC)[reply]

I would still like to know if the universe will exist for an infinite length of time or not. Perhaps it goes through an infinite number of big bangs. Or perhaps there are an infinite number of universes, where I am having exactly this same thought. Or perhaps nobody will ever know.

According to Thermodynamics things get hotter and more disordered unless you keep supplying them with enegy, and since there's nothing outside the universe to put energy into it, it will end in a 'heat death' (although it will only warm up by a tiny fraction of a degree due to its size).

If you're wondering whether or not this is likely, and how reliable thermodynamics is, one of the famous physicists working at the turn of the century in quantum mechanics (I forget who - does anyone know?) said in investigating the apparently bizarre world of the sub-atomic, that he was willing to reject every Law of Physics except Thermodynamics. So I'm voting for heat death.

There is modern work that contradicts it, but I'm not familiar with it and I'd guess it was a little dubious.

Re extra dimensions etc, I think it's best to remember what the logical positivists were trying to say: if there's no good evidence for it or it doesn't help to explain things that were previously inexplicable (rather than pander to wishful thinking) then there's no reason to say it. Rentwa 15:11, 3 September 2006 (UTC)[reply]

Read Ultimate fate of the universe. --Lambiam ^Talk 16:22, 3 September 2006 (UTC)[reply]

Lambiam - do you know which Physicist it was who said he was willing to discard everything except the second law? Rentwa 19:27, 3 September 2006 (UTC)[reply]

I'll take that as a 'no', then, shall I? :) Rentwa 12:58, 4 September 2006 (UTC)[reply]

Rentwa - Fair enough. There's a much better reason for it not to be taught in arithmetic - the fact that they're completely different. For the rest - I wrote an intentionally lazy and hand-waving description because I figured it'd get the point across. I'm not quite sure, though, whether you're agreeing with me or disagreeing. I'm also curious whether I'm farther in math than you are, or vice versa. I'm not familiar with the phrase "functional analysis". To put it in the most rigorous, or at least most clear, way I've learned:

1a)

f(x)=0x\qquad

1b)

\lim _{x\to \infty }f(x)=0

1c)

\lim _{x\to \infty }0x

is of the form 0 times infinity, so in one situation 0 times infinity = 0

2a)

g(x)=x(1/x)\qquad

2b)

g(x)=1,x\neq 0

2c)

\lim _{x\to 0}g(x)=1

3a)

g(x)=h(x)i(x),h(x)=x,i(x)=1/x\qquad

3b)

h(0)=0,\lim _{x\to 0}i(x)\to +\infty

3c)

\lim _{x\to 0}g(x)=\lim _{x\to 0}h(x)i(x)=0(\lim _{i(x)\to \infty }i(x))

is of the form 0 times infinity as well, but evaluates to 1. The same steps could show that lim(x->0)x²(1/x)⁴=inf. Or just looking at their graphs, which is basically what this formalizes, could show the same thing - a flat line at one place versus a flat line at another place versus a vertical asymptote. So, the statement "0 times infinity" is ambiguous. It's not that any of the answers is wrong, it's that the right answer depends on the actual relationship between the two objects/values/measurements described. Black Carrot 21:32, 3 September 2006 (UTC)[reply]

I studied Maths up to postgraduate level, although I don't work in the field now (and I never taught in any very prestigious institutions when I did).

Argument 2) is fine I think except that there are very rigorous rules in analysis for letting you say that the value is what it looks like at the point you can't work out (obviously the graph is flat across its domain with g(x) = 1), and without my text books to hand I can't remember what they are (I'm on holiday and still spending 10+ hours a day ranting on wikipedia - how sad is that?)

I'm agreeing with you that you've got a good way of showing that 0 x infinity = 1, I'm just not sure it's rigorous without checking the rules, whereas I don't need to check the rules to know that the sum of 0s = 0 or to remember the axioms of arithmetic from my undergraduate Logic course.

'Functional Analysis' = 'Analysis' = rigorous treatment of functions, it's the broad topic that calculus falls into at university.

What you're saying at the end is what led me to analysis and the philosophy of logical positivism - that you have to think very carefully about what you mean, the symbols you use and the rules governing those symbols or you end up talking rubbish. Rentwa 22:55, 3 September 2006 (UTC)[reply]

THeres no such thing as zero probability in nature anyway. Only in mathematics. So the argument is rather sterile.--Light current 23:00, 3 September 2006 (UTC)[reply]

Rentwa - I'm in undergraduate Calc II, plus some study beyond the classroom. So, you'd get the benefit of any doubt. You've got a good point, that it takes a bit more to actually prove that the limit works that way, but I'm almost certain that the necessary argument exists, somewhere. I think that because we've evaluated those limits and ones like them in class many times, and the teachers seem pretty sure that that's how it winds up. What are some good textbooks for that kind of thing? Black Carrot 03:02, 4 September 2006 (UTC)[reply]

Light current - A fair point. Black Carrot 03:02, 4 September 2006 (UTC)[reply]

I always give myself the benefit of the doubt :) . And the more I think about it, the more 'Prove f(x) = x (1/x) is continuous' sounds like a question, so you're probably right, it's just I want to see 'blah blah (such and such theorem), blah blah (since x is a member of R) blah blah etc before I give you a tick :) . To take things to a more philosophical level (and draw attention away from the fact that I can't remember the rules for continuity), both the 'infinite monkeys' and 'Schrodinger's Cat' strike me as proofs by contradiction eg:

assume we can apply limits to real life,

do various other steps, all 100% logical,

conclude monkey can write Hamlet,

in a lucid moment realise that a monkey couldn't write Hamlet, thus proving original assumption is wrong.

Likewise:

assume quantum super position,

use various other steps, all 100% logical,

conclude cat can be simultaneously dead and alive,

in lucid moment realise cats are one thing or the other, thus proving quantum super position is wrong. Rentwa 09:21, 4 September 2006 (UTC)[reply]

Iron

What do you get when you mix oxygen with iron? 64.12.116.74 20:06, 2 September 2006 (UTC)[reply]

I'd like to help you out, but my chemistry is rusty. ---Sluzzelin 20:08, 2 September 2006 (UTC)[reply]

Ha Ha. I think you could get a lot of things (one of upto sixteen different oxides) depending on how you did it. But see iron, Iron oxide, ferric oxide to start.--Light current 20:11, 2 September 2006 (UTC)[reply]

Hehe, sluzzelin, it depends though, on temperature and for how long, but if given enough time and or heat, you will get the iron oxides light current mentioned. Philc _T^E_C^I 20:53, 2 September 2006 (UTC)[reply]

I prefer to call it "ironic oxide", since you work hard to replace your rusty old car with a shiny new car, then it turns to rust as you work hard for the next shiny new car, etc. :-) StuRat 21:25, 2 September 2006 (UTC)[reply]

Quite simple

Dirk vs. StuRat? ≈Eh-Steve 21:08, 2 September 2006 (UTC)

Hmmmm... --Russoc4 02:02, 3 September 2006 (UTC)[reply]

But to make it a fair fight, you must use both our full screen names, so DirkvdM vs StuRat. StuRat 02:18, 3 September 2006 (UTC)[reply]

Im far too common to enter such a contest!--Light current 02:44, 3 September 2006 (UTC)[reply]

Are we being pitted against each other? As if we need the incentive of others for that. And which one is supposed to be "quite simple"? Anyway, there appear to be many StuRats. For example, is this you? If we limit this to Wikipdia we get StuRat 538 vs DirkvdM 886. But to distinguish between us without limiting the search to Wikipedia we could use our real names. here's mine: Dirk van der Made, with a score of 1270. DirkvdM 06:26, 3 September 2006 (UTC)[reply]

When I picked your links I get me ahead with 362 vs. 348 for you. StuRat 07:45, 3 September 2006 (UTC)[reply]

What, you get significantly different results? Shouldn't this be the same the world over? DirkvdM 08:08, 3 September 2006 (UTC)[reply]

That's what I was expecting. How many hits does everybody else get on Dirk's links ? StuRat 11:31, 3 September 2006 (UTC)[reply]

I'll ask about this at the IT ref desk. DirkvdM 13:53, 3 September 2006 (UTC)[reply]

I should note that there's this other Dirk van der Made from the 13th centrury. Excluding him gives only 865 results. Most of these are a result of the popularity of my photographs on the Internet. Looking through that list is quite interresting - haven't done that for some time. I now see that someone thinks I have tremendous potential. I just don't know for what (my life's story :) ). DirkvdM 07:22, 3 September 2006 (UTC)[reply]

Saying you have "potential" is shorthand for "wasted potential". It's something like saying a woman has "a good personality", LOL. StuRat 08:02, 3 September 2006 (UTC)[reply]

I have some 2000 more Wikipedia edits:

StuRat's edit count

DirkvdM's edit count

StuRat 07:36, 3 September 2006 (UTC)[reply]

If you have (slightly) more Wikipedia edits than me and I get more Wikipedia hits, does this mean that I am talked about more? In other words, am more interresting than you? DirkvdM 08:08, 3 September 2006 (UTC)[reply]

Yes, apparently you are all talk, while I am a man of action. Note that thousands of additional edits isn't a "slight" amount, and I don't agree that you have more Wikipedia hits from Google (that's not what I get when I pick your links). StuRat 11:36, 3 September 2006 (UTC)[reply]

But you have to view that in relation to the total count. You have 9394 edits and I have 7628 edits. That's a difference of 1766, and 'thousands' is in my vocabulary at least more than 2000. Now who isn't a math graduate? Ok, so you have 23% more edits and are in that sense 23% more action (but is ceterus paribus? How many political parties have you started?). But based on my Google results I am 65% more talk, and thus 65% more interresting. DirkvdM 13:53, 3 September 2006 (UTC)[reply]

I said Wikipedia edits (as opposed to total edits), which favors me by 6327 to 3528. That's a diff of 2799, or 79% more for me. I can both do math AND read, whereas you, apparently, can only talk. :-) StuRat 03:43, 4 September 2006 (UTC)[reply]

What do you know, I may be a mute. You mean 'write'. Anyway, you just made that up. If you meant 2799, you wouldn't have said 'some 2000' but something like 'well over 2000' or 'almost 3000'. Also, I'm more of a help because I've got infinitely many more edits there than you. Ok, that was silly. :) DirkvdM 07:25, 4 September 2006 (UTC)[reply]

We are making up the rules of this contest as we go (and as suits us). Eh-Steve, could you emphazi your intentions here a bit more? DirkvdM 08:08, 3 September 2006 (UTC)[reply]

5 wikidollars on StuRat. And, just in case, put me in for 4 wikidollars on DirkvdM, too. freshofftheufo ΓΛĿЌ 10:04, 3 September 2006 (UTC)[reply]

Being a bit indecisive? You place 20% more on StuRat. Ist that based on the 23% more action? But then what about my 65% more interrestingness? (As exemplified by my linguistic inventiveness.) DirkvdM 14:02, 3 September 2006 (UTC)[reply]

5 is 25% more than 4, since the basis is 4. However, 4 is 20% less than 5, since the basis is 5. StuRat 04:34, 4 September 2006 (UTC)[reply]

Hmmm, I wonder how that sneaked in. Maybe I did use the wrong base. Anyway, 25 is closer to 23, so that fits even better. Btw, this reminds me of the Philippines, where (like in the US) they very oddly substract taxes from the prices and then add them back again before the sale. Thus, you often get very weird prices, but with tax they are miraculously round again. In one hamburger joint they hadn't done this right, though, calculating the substracted tax percentage based on the full price, so adding it back (based on the 'untaxed price') gave too low a result. I decided not to point this out because I had a hard enough time getting a hamburger (in a hamburger joint!). "A hamburger please" "A hawaiian burger?" "No just a plain hamburger" "A cheeseburger?" "No, a hamburger" "A what-have-you burger" "No, I just just want a plain fucking hamburger" Startled looks, but I thought I had gotten through to her. But then "What about your drink sir?" AAARghhhh!! DirkvdM 07:25, 4 September 2006 (UTC)[reply]

We saw a Dutch guy on holiday. He had 'Fuck off' tattooed on his leg. We stared at him for a long time. Eventually we went up to him. 'You have 'Fuck off' on your leg' we said. 'Yes' he said. 'Why have you got 'Fuck off' tattooed on your leg?' we said. 'It's a very useful phrase in Holland' he said. We backed away slowly... Rentwa 19:56, 4 September 2006 (UTC)[reply]

In Los Angeles, when you go to Jack in the Box for a hamburger, the Hispanic server says "Welcome to Yak in the Box" ... it must be a mighty big box ! :-) StuRat 08:30, 4 September 2006 (UTC)[reply]

This might be a challenge for me to suitly emphazi, because I just wanted to see what would happen between you two (Y'all are always quarrelling about lefty vs. US politics, as far as I can tell, more than any other 2).

So... How about a deathmatch (like giant seagull vs. Human)? ≈Eh-Steve 15:45, 3 September 2006 (UTC)

As long as it's virtual death (what else could it be over the Internet?). Btw, it's mostly over politics that we're head to head. When it comes to science and especially humour we're often of the same mind. However, in all areas we try ot outwit each other, and to some that might come across as something more serious.

So a deathmatch it is. What are our weapons? DirkvdM 17:54, 3 September 2006 (UTC)[reply]

You don't need any weapons, you're already working to arm the terrorists with nuclear weapons, so they will get me for you. StuRat 04:24, 4 September 2006 (UTC)[reply]

The Netherlands supply the US with arms? DirkvdM 07:25, 4 September 2006 (UTC)[reply]

I think it should be te person withe the fewest Google hits who wins. This shows the originality of the name. In this case, I lose by a massive amount! 8-)--Light current 18:05, 3 September 2006 (UTC)[reply]

HEY you two! My Dad's bigger than either of your Dads. So there!--Light current 03:49, 4 September 2006 (UTC)[reply]

Please dont turn this desk into a complete joke eh?--Light current 03:57, 4 September 2006 (UTC)[reply]

Damn you both for letting all this fun go on without telling me! Sure, I can't compete with either Dirk or Stu when it comes to edits or google hits, but as the RefDesk's resident right-wing, Canadian, pro-US, anti-UN, Republican, shit-disturbing Zionist Jew, I'd think I'd at least get honourable mention! Loomis 02:49, 5 September 2006 (UTC)[reply]

Maybe I'll sick you on Dirk, to counter all those nuclear weapons he wants to give to terrorists to get me. :-) StuRat 07:42, 5 September 2006 (UTC)[reply]

What? Nobody's mentioned Magical MD5 Battle? StuRat won against DirkvdM after 5 rounds. --Kjoonlee 17:43, 5 September 2006 (UTC)[reply]

StuRat: ヽ( ´￢`)ノ, DirkvdM: (ﾉд-｡). Can I get my 5 Wikidollars now? freshofftheufo ΓΛĿЌ 05:54, 6 September 2006 (UTC)[reply]

Northern Cardinal question

There was a fledgling cardinal in our yard about 2 weeks ago--it didn't look like a cardinal, but it was being fed by cardinal parents, and it couldn't fly. We were worried about it because it kept hopping into dangerous areas, like the sidewalk, etc. Now there is a red male cardinal hanging around, but no parents. Is it possible this is the fledgling? How long does it take a fledgling to get its red feathers?

Thanks!

This is a rather entertaining story until you realise it's about birds. :) DirkvdM 06:28, 3 September 2006 (UTC)[reply]

I remember when the racehorse Cardinal was retired. The headline said "Cardinal out to stud". JackofOz 12:08, 3 September 2006 (UTC)[reply]

At least it was not Cardinal Sin. --Lambiam ^Talk 16:42, 3 September 2006 (UTC)[reply]

sun slowing down

i know the moon is slowly nicking the earths angualr momentum, so does in theory the planets takie angular momentum from the sun? if so, excluding events like sun turning into a red gaint (or the IAU decides to change definition of a planet again)how long would it take with the current planets to stop the sun spinning?--Colsmeghead 23:01, 2 September 2006 (UTC)[reply]

Not sure, but since the Sun is almost 1.98×10³⁰ kilograms, and even Jupiter being a mere 1.90x10²⁷ kilograms, the combined mass of all the planets and other objects in the solar system, probably aren't enough to actually cut into the Sun's angular momentum, at least not in a way that will have a significant effect within the life time of the solar system--71.247.243.173 00:06, 3 September 2006 (UTC)[reply]

That's only 1/1000th of the sun's mass... sure it's small, but is it really negligible? Aaadddaaammm 01:14, 3 September 2006 (UTC)[reply]

It's the tides that cause Earth to lose angular momentum. Using this formula, I calculated the tidal forces that the planets exert on the Sun:

Mercury: 3.140135 x 10²⁰ N

Venus: 7.104643 x 10²⁰ N

Earth: 3.300665 x 10²⁰ N

Mars: 1.001771 x 10¹⁹ N

Jupiter: 7.446589 x 10²⁰ N

Saturn: 3.619013 x 10¹⁹ N

Uranus: 6.786093 x 10¹⁷ N

Neptune: 2.072556 x 10¹⁷ N

So if Jupiter and Venus are at a 90-degree angle with respect to the Sun, their tides will cancel each other. If there's a syzygy involving Mercury, Earth, and the Sun, and if Venus (or Jupiter) is at a right angle to Mercury, then Mercury and Earth's combined tide will almost cancel that of Venus/Jupiter. Also, if Mercury is at a right angle to Earth, their tides will cancel.

As you can see, the situation is very complex when there's 8 planets involved. With the planets cancelling and overpowering each other's tides, we probably need to run a computer simulation to find out what happens. But even if the Sun is losing angular momentum, it won't stop rotating. I'll use Earth as an example to explain why: the Moon's gravity changes the shape of the Earth, slowing Earth's rotation and in the meantime lengthening the Moon's orbital period. When the length of an Earth day is equal to the Moon's orbital period, Earth's shape will not change anymore, because the Moon will be stationary relative to our planet. When this happens, the length of a day will be fixed forever. --Bowlhover 05:38, 3 September 2006 (UTC)[reply]

But, as you say, the solar system is more complex, with all its planets and planetoids and what have you. I wonder if all planets, through their mutual attraction would in the end become stationary relative to each other. But since a given orbit period corresponds to a given orbital radius, all planets would have to merge for this to happen. Is that a state the solar system is moving towards? DirkvdM 06:37, 3 September 2006 (UTC)[reply]

No, the planets don't have any reason to merge. The force that the planets exert on each other is very small, certainly not enough to change the planets' orbits to any extreme degree. --Bowlhover 06:54, 3 September 2006 (UTC)[reply]

I think, in theory, they would eventually merge. But, since that would take far longer than the time before the Sun goes nova, it's not really important. StuRat 03:00, 9 September 2006 (UTC)[reply]

September 3

Genetic Engineering's impact on Plant Biodiversity

What are the impacts of Genetic Engineering on Plant Biodiversity? I know a bit and have already looked at http://www.biotech-monitor.nl/2805.htm and a couple of wiki articles.

Cheers, Daniel.thorpe

Basically, as people engineer plants so that they are more profitable/healthy/etc (desirable), the biodiversity goes down because the undesirable plants get unpropagated. When a disease hits that is very detrimental to a certain genome, like the desirable genome, then all those plants die. Without other genomes readily accessible, it is hard to replant. In theory, if we all converted to the most desirable genome, and then it died, well there'd be no more of that type of plant. M.manary 00:12, 3 September 2006 (UTC)[reply]

but none of those effects are specific to genetic enginering, if we all switched to one non-gm type of plant we'd go down the same road. Xcomradex 00:19, 3 September 2006 (UTC)[reply]

surely introducing wierd and wonderful genes into plants, at least in the short term, increases the biodiversity of plants? You're creating a new species. Whether this species has an effect on others to effect biodiversity, who knows?! Aaadddaaammm 01:13, 3 September 2006 (UTC)[reply]

Transgenesis does not, in itself, create a new species. Most genetic engineering of plants for commerical purposes, can be thought of as simply a way of accelerating the same changes that could potentially be brought about by many, many years of selective breeding. The modern farming methods that grow the GM plants may well decrease biodiversity, but the process of genetic engineering - transgenesis - itself is surely increasing biodiversity. Rockpocket 01:56, 3 September 2006 (UTC)[reply]

Ahh, yes but wouldn't (due to Darwin's theory) the GM Plants become the "fittest" and eventually become the new dominant species of plant in the area? Especially if they were allowed to breed, wouldn't a disease resistant, or whatever the modification was, plant become a weed-esque organism? There is also the Chance of something like Agrobacterium Tumafaciens (I think thats the spelling) could asexually transmit the changed genomes. Thanks for your help by the way. Daniel.thorpe 10:28, 5 September 2006 (UTC)[reply]

Interstellar travel

Let's assume we can aim a spacecraft in the direction of a star (or rather, where the star will be when the spacecraft gets there), fire the thrusters, and have it arrive within 15 AU of the star without any further navigation. Under this unrealistic assumption, and using current technology, is it possible to:

Use RTGs to aim the spacecraft at Alpha Centauri and fire the thrusters.
Shut the spacecraft down.
When the spacecraft is very close to the star, have its solar panels generate enough energy to power a light bulb.

If this is possible, is it possible to send a signal back to Earth to confirm the spacecraft's arrival? If so, how about sending a picture and some measurements back to Earth? --Bowlhover 06:15, 3 September 2006 (UTC)[reply]

If thousands of years have passed, the nuclear fuel may have lost much of it's radioactivity by then, unless you choose a fuel with a very long half life, in which case only a very low power output would be produced. StuRat 07:13, 3 September 2006 (UTC)[reply]

Was it really necessary to shove this in here? Couldn't it just have gone after mine? Seriously, what the hell? Black Carrot 20:24, 3 September 2006 (UTC)[reply]

Mine was a response to Bowlhover, not to you, so I placed it after his. I was even careful to double indent my comment so it was also clear that yours is not a response to my comment. Also, mine was only one sentence, so didn't push yours away from the original question by much, whereas yours was 4 sentences long. So what's the problem ? StuRat 02:48, 4 September 2006 (UTC)[reply]

We have to wait ten years to get news back from Pluto. Does it really seem plausible that we could set up communication with another star on a reasonable timespan? The Alpha Centauri article says it'd take 4.39 years just for the return message to flash back to us, at the speed of light. Black Carrot 06:23, 3 September 2006 (UTC)[reply]

Other than that, though, and the near insurmountable difficulty of calculating and following the right trajectory, and the additional difficulty of sending a tight enough signal in just the right direction to hit the Earth half a decade later, I don't see why not. Black Carrot 06:29, 3 September 2006 (UTC)[reply]

It doesn't take ten years to get a signal from Pluto - it isn't ten light years away. Stop picking on that poor former-planet! I'm more concerned about the amount of energy it would take to send a detectable signal from the other star. I don't think that solar panels would cut it. Clarityfiend 20:31, 3 September 2006 (UTC)[reply]

I know that sending a probe to Alpha Centauri will take a very long time, but even if it takes 18000 years, that's OK. The reason I asked the question was because I'm curious about whether any electronic equipment can survive in empty space for tens of thousands of years, and still be operational.

As a separate question, what's currently the most realistic way to travel to Alpha Centauri? Again I don't care about the time it takes, just that it's realistic. --Bowlhover 06:49, 3 September 2006 (UTC)[reply]

My plan:

1) Build a huge linear accelerator, powered by an onboard full scale nuclear reactor, in the asteroid belt.

2) It will then clamp onto a metallic asteroid which will be at the front end of the accelerator, and be approximately 90% of the total mass, with the ship being the remaining 10%.

3) Move the accelerator out of the plane containing the planets, and into a position on a line between the Sun and Alpha Centauri. This movement can be done with conventional booster rockets which are then discarded.

4) Aim the accelerator toward AC, then fire up the linear accelerator. A continuous mining operation will remove metal from the asteroid, which is then accelerated to the speed of light and ejected toward the Sun (so the stream doesn't pose a hazard to anyone). This propels the ship at approximately 1 g.

5) After about a year, the ship will be at near light speed and half of the mass will have been used up. Turn the engine off.

6) Cruise for about 4 years at near light speed, then rotate the ship the other way around (rockets can do this).

7) Repeat the process to decelerate at 1 g for about a year, with the matter stream directed into AC. This will use up about 50% of the remaining mass, which is 25% of the original mass.

8) Turn the ship slightly, near the end of the burn, to achieve a stable orbit about AC.

9) You've reached AC in about 6 years. Have fun exploring ! StuRat 11:00, 3 September 2006 (UTC)[reply]

After edit coflict:

Possible? Maybe. Pointless? Certainly. A few decades from now we will be able to build a spaceship that will overtake the one we send now before it reaches the star. This will remain true until the time it takes a spacecraft to get to a given star will approach the time it takes to develop a considerably faster spacecraft. By that time we might also live longer than that time, so people then might be interrested in doing this. But by that time we may also have other means to get that info without travelling there, so we may never travel to the stars. DirkvdM 06:59, 3 September 2006 (UTC)[reply]

Any traditionally rocket propelled ship would surely be picked up a century later by our then much faster ships, and put into a museum. This takes all the fun out of spending billions of dollars to send the first ship, doesn't it ? StuRat 07:05, 3 September 2006 (UTC)[reply]

Unless Klingons see it first and use it as a target for shooting practice. DirkvdM 07:28, 3 September 2006 (UTC)[reply]

Don't be silly. It would be the Kzinti. Clarityfiend 20:33, 3 September 2006 (UTC)[reply]

The only plausible type of interstellar travel I can think of, is outlined here, all the way at the bottom of the section. Catastrophe Surfing, kind of long winded--VectorPotential^{71.247.243.173} 11:47, 3 September 2006 (UTC)[reply]

Product Success

If I wanted to find out how successful something's been (how many copies a book's sold, say) how could I get that information reliably? Black Carrot 06:33, 3 September 2006 (UTC)[reply]

With books it's particularly hard because in a lot of cases the numbers collected are actually the books sold to the stores. Book stores usually overorder and send the stuff they don't sell back, resulting in either books being warehoused or destroyed. That's why I personally prefer the Print on Demand model as it wastes a lot less paper. - Mgm|^(talk) 08:54, 3 September 2006 (UTC)[reply]

rubella virus

what system in the body does the rubella virus (aka German measels) occur in?

any help would be greatly appreciated!! Sammie hero 07:14, 3 September 2006 (UTC)[reply]

The Rubella article will tell all... "The virus usually enters the body through the nose or throat. Like most viruses living along the respiratory tract, it is passed from person to person by tiny droplets in the air that are breathed out. Rubella can also be transmitted from a mother to her developing baby through the bloodstream via the placenta." Rockpocket 08:20, 3 September 2006 (UTC)[reply]

Time dimensions

There are (at least) three spatial dimensions. These are expressed as exponents of length. I can visualise m, m² and m³. But in, say, acceleration, there is an exponent of time: m/s². Does this indicate a second time dimension? And can I use thinking about acceleration to get an idea of what that Second Temporal Dimension is like? The link touches on the subject, but doesn't quite help me. Also, power is kg.m²/s³. Does this mean there is a Third Temporal Dimension? And more? Also, I dn't know of any derived units that use a higher spatial dimension than three. Are there? DirkvdM 07:54, 3 September 2006 (UTC)[reply]

I always thought of acceleration as (meter per second) per second. That way I never had to imagine time squared. Now you have me confused! The SI unit for polar moment of inertia is meter to the fourth power (m^4). ---Sluzzelin 08:33, 3 September 2006 (UTC)[reply]

No, units have nothing to do with dimensions. StuRat 10:41, 3 September 2006 (UTC)[reply]

Could you emphazi that a little more suitly? Surely, m² and m³ have something to do with the second and third spatial dimension. And it takes just a small mental step to think that the use of s² indicates a second temporal dimension. DirkvdM 12:17, 3 September 2006 (UTC)[reply]

Units are generally a summary of the calculation, in this case accelaration is expressed as a vector quantity with dimension length/time², which means you square time, not you multiply two seperate time dimensions together. If there was more than one time dimension you would know about it. For a start you'd be a Tachyon. Philc _T^E_C^I 12:37, 3 September 2006 (UTC)[reply]

Well let me reverse it then. If s² is not about a second temporal dimension, then is m² also not about a second spatial dimension? Surely it is. Or let me ask this in more general terms. What does it mean to square a unit?

But let me follow your lead. Suppose I'm a tachyon. :) The article says a tachyon "can never slow to light speed or below". In other words, it exists beyond the speed limit, so not in our reality. So in another dimension? I must admit that I'm totally out of my league here, but you brought up the tachyon, so don't blame me. :) DirkvdM 13:36, 3 September 2006 (UTC)[reply]

Hehe, fiar enough, m² doesnt necesarily mean two dimentional space, though it can be used to mean this. I can also just implying a square relationship between this variable and another, ke=½mv², here we have a v², but all it is saying is that it is a square relationship between ke/½m and v, v is still a single value, and the ² does not imply that it is a 2-dimensional value.

Tachyons I brought up because above the speed of light things get complicated, for example, above the speed of light spacial and time dimensions swap round, so there are 3 time dimensions and 1 spacial dimension. Where as we recquire an infinite amount of energy to reach the speed of light, tachyons recquire an infinite amount ot decalerate to the speed of light. Now I dont quite understand the physics of navigating multiple time dimensions or anything, but tachyons exist in them, and mutliple time dimensions are possible, and exist in our univers, but we can only interact with one. Which is probably for the better, but there existence isnt anything to do with units involving time² variables. Philc _T^E_C^I 13:48, 3 September 2006 (UTC)[reply]

metres per second squared is just a shorthand for metres per second per second. It doesn't really mean metres per squared second. Skittle 14:21, 3 September 2006 (UTC)[reply]

Yeah. a m/s²=(dm/ts)/ts=(distance/time)/time. It's not that there are two separate dimensions of time, it's that you're working out an intricate relationship between a dimension of distance and the one dimension of time. You would use essentially the same math, though, if there were two time dimensions to consider. You could also have some fun linking it to spatial concepts by adding in calculus. The integral of acceleration (distance over time squared) d-time, is velocity (distance over time), the integral of which, d-time, is just distance. So, given a graph of acceleration from a starting time to an ending time, velocity is the area under the graph, and distance is the area under that graph. Both computations use the same unique time dimension, though. Black Carrot 20:19, 3 September 2006 (UTC)[reply]

There's a difference between meters squared and square meters. The former you can get when you multiply two quantities together, such as velocity; the latter involves the second spatial dimension. The confusion arises because the same notation is used for both.

That being said, there's no reason I can think of why multiple time dimensions can't exist. We just aren't equipped to detect them. Maybe you should talk to the Wormhole Aliens of Star Trek: Deep Space Nine. (Cue the Twilight Zone theme)...for your perusal. Clarityfiend 20:41, 3 September 2006 (UTC)[reply]

Not that I expect an answer to this late reply, but isn't the same notation used for a reason? Or reasoning the other way around, if these are two different things, then shouldn't there be different notations? DirkvdM 20:46, 12 December 2006 (UTC)[reply]

The fact that you can multiply 1 second by 1 second and get 1 second squared doen't imply anything about reality. I could imagine a quantity with units of seconds^100, but that doesn't mean I have created 100 time dimensions. --bmk

If two things have the same properties they are the same. Or at least that's how it should be in physics. It's not like the first time in (m/s)/s is any different from the second one (no pun). At least in the sense that length is no different whether it's width or height. But together they form an extra dimension. So if that goes for length, shouldn't it also go for time? As a variation of my first statement, the same mathematical operation must have the same meaning wherever it's applied. If you apply adding a power to length once (m² in stead of m¹) you express an extra dimension. If you do that again (m³ in stead of m²), you get an extra dimension again. How would one describe things in the fourth spatial dimension? with m⁴, right? So here, raising to a different power seems to express a different dimension. And why would the same mathematical operation have a different meaning when applied to a different unit? DirkvdM 08:45, 4 September 2006 (UTC)[reply]

If time had 2 dimensions your life could be an infinitely long spiral in some fixed area. Bounded yet eternal. Three square yards and...no, dammit, I can't think of a decent pun!! Rentwa 20:03, 4 September 2006 (UTC)[reply]

No, I'm pretty sure thats not right,time still has rules even if there are multiple dimensions, there are still issues with going backwards in it (i.e. its not possible). Philc _T^E_C^I 20:15, 4 September 2006 (UTC)[reply]

If time had two dimensions, the Universe would be unstable. Q.v. Spacetime#Privileged character of 3+1 spacetime. -- Fuzzyeric 00:31, 6 September 2006 (UTC)[reply]

No, the s² does not imply an extra time dimension. As someone said above, it's just a shorthand. The formal expression for acceleration is d²x/dt², i.e. the second time derivative of position; which does equal m/s² (for meters and seconds) which is the form people who haven't leanred calculus know. Would people still ask if there was an extra time dimension if it was expressed as v/t?

Weird sky

While I was coming home today, I noticed something weird about the clouds. They had these thick, dark bands, which were perfectly straight-edged and converged into a similar area out at sea. It kind of looks like that effect when the sun is setting, and some bands of light come through the clouds. The bands, however, were in the east, and the sun was in the west. I took photos when I walked to the beach later, but they didn't come out great, and the bands had faded lots. Thanks. --liquidGhoul 09:40, 3 September 2006 (UTC)[reply]

If you live in the North Eastern United States, you might have been looking at what was left of a tropical storm, but I suppose you'd probably notice that. Ok, scratch that, your user page says you're Australian (:VectorPotential^{71.247.243.173} 12:02, 3 September 2006 (UTC)[reply]

Here is a pic. The photos were worse than I thought, as you can only see one of the bands (most had faded by now), and it seems they were light bands. It was just there were so many bands previously that the dark looked the minority, hence they were dark bands. It is kind of hard to see, but is still visible. --liquidGhoul 12:39, 3 September 2006 (UTC)[reply]

I assume it's the sun. When it shines through the holes in the clouds, and there is sufficient mist in the air, you'll see the rays, like you'll see a laser beam when it passes through smoke). I see that effect quite often here in Germany. —da Pete (ばか) 14:13, 3 September 2006 (UTC)[reply]

He said it wasn't the "sun filtering through the clouds effect". Could it be that they were just indications of rain far off? No, after taking a second look that doesn't look too likely either. Strange. freshofftheufo ΓΛĿЌ 14:35, 3 September 2006 (UTC)[reply]

(edit conflict)Yeah, it wasn't shining through, you can see from my shadow in the photo that the sun was behind me, not the cloud. I have seen rain out at sea, and that usually starts much lower, and is parallel. When this was obvious, there were some bands that were vertical, but most were at different angles, and converging to the same general area. The best explanation I could think of was reflections of the sun off the cloud, but there is no way in hell that it could be that perfect looking. The clouds should reflect it in all different directions. Thanks --liquidGhoul 14:42, 3 September 2006 (UTC)[reply]

Take a looksee at anticrepuscular rays. Weregerbil 15:00, 3 September 2006 (UTC)[reply]

Wow, that is awesome. I will have to keep an eye out for it more often. Thanks. --liquidGhoul 15:14, 3 September 2006 (UTC)[reply]

Yes, I would say those are anticepuscular rays. Nice photo, if you see it again and can get a good picture, stick it on the article! — [Mac Davis] (talk) (Desk|Help me improve)

Fat or Muscle?

Hello guys....I weigh too much(about 195 pounds,173 Cm height) and hence I have decided to fast one square meal.I have a hanging belly...Now if I just fast and don't do excersize,will my belly get reduced?...or just my muscle get reduced?..I checked my weight and I can read it's dropping pretty well every week.If my weight is dropping but I can't see pretty changes in my belly shape..Is it good to fast? and continue this way? or must I do excersize?...I'm trying to reduce my calorie intake to 1000kcal per day.Now I have reduced my wieght to about 155 pounds and I'm looking not that obese but my belly is still hanging...Can anyone help me in this please?...Thanks in advance..

What's your age ? You are more likely to sag after losing weight if you're older. In any event, the cure is to exercise. I suggest sit-ups for the belly. If you have lots of loose skin, though, then surgery would be required to remove it. StuRat 10:36, 3 September 2006 (UTC)[reply]

Doing sit-ups does not reduce the amount of fat on the stomach, it only increases the muscle underneath. You won't see any results from sit-ups until the fat above it is removed. You should be doing aerobic exercise, as that will increase the health of your heart (then other organs) as it has probably been damaged from being overweight, depending on how long you were overweight. This should also result in it being easier to lose weight. Go running or swimming to achieve this. Also, make sure you are getting all neccesary nutrients, a malnourished body will hold on to as much fat as possible. This is achieved through eating healthily (vegies, nuts, meat). Everybody is different as to where they will lose weight last, for you it is probably the stomach. --liquidGhoul 11:10, 3 September 2006 (UTC)[reply]

At 155 pounds, I would say the excess fat is already gone, all that is left now is to tone the muscles. StuRat 11:25, 3 September 2006 (UTC)[reply]

I agree with the advice about exercise. And as for your gut, burned fat tends to be harvested first from around the organs, and later redistributed. You may not see the final results of your weight loss for two or three months, at which time your body has finished re-balancing the fat content of your body. Anchoress 11:17, 3 September 2006 (UTC)[reply]

To add to the above: Do an activity that you enjoy which forces you to exercise. It's a lot easier to aim for a more active lifestyle than it is to start exercising all of a sudden, though the difference is really only in the perception. A sagging belly is a sign that your body isn't holding itself together, and something as seemingly unrelated as back exercise can have noticeable results. One of the most important things is keeping a routine, and you have to be comfortable doing it. Reducing your calorie intake may help, but that should never be the focus of your "diet lifestyle". I mean, think about it this way: Exercise requires concious physical action, fasting requires no extranuous act other than resisting the urge to eat. Do you really think that fasting could logically have more benefit than exercise? There are lots of studies that suggest fasting has the opposite effect on dieting, as the body goes into a calorie conservation mode and thus you gain wait easier from smaller amounts of food. freshofftheufo ΓΛĿЌ 11:29, 3 September 2006 (UTC)[reply]

When I used to go cycling a lot, it kept my tummy really trim. 62.253.52.65 13:55, 3 September 2006 (UTC)[reply]

Hearty Thanks for yout tips all friends.I'll keep all these in my mind...I have one more to ask...I'm now 24yrs old.I now look perfect and fit,say all my girl friends...But when I remove my shirt I still get embarrassed since I have loose muscles\fat whatever hanging esp the belly..But my shoulder and hip bones are almost visible and I look skinny except for my belly which is very loose...Is it just the fat or loosly packed muscles?...Now to reduce this what kind of steps should I have to follow?..Can dieting reduce this or should I have to follow the exercise as described earlier?....

Is exercise really "the cure?" Prof. Richard A. Muller disputes [12], and says the best way is just to eat less. Muscles don't "hang" it is either skin or fat that does. — [Mac Davis] (talk) (Desk|Help me improve)

Muscles may not hang, but the ligatures and bones that are supported by them do, particularly the hip and shoulders. A good posture can go a long way towards making you look healthy. I haven't seen Muller's stuff before, but I'll take a look at it now. freshofftheufo ΓΛĿЌ 05:55, 4 September 2006 (UTC)[reply]

I've read it, but I don't see what that proves. It's a non-conclusive report (more like a diary) by a high-profile physicist. Good for him that he lost 30 pounds, but it's not exactly a paper that I'd quote. freshofftheufo ΓΛĿЌ 06:01, 4 September 2006 (UTC)[reply]

That's a good article. I like the guy who wrote it. It's worth keeping in mind, though, that it did take him seven months to lose all 30 pounds. How long would it have taken if he'd excersized as well? Black Carrot 19:54, 3 September 2006 (UTC)[reply]

Something else to keep in mind is that you can still reduce your caloric intake by eating smaller meals rather than starving yourself for half the day. That helps keep your basal metabolism up. I think that's what bodybuilders do. AEuSoes1 21:03, 3 September 2006 (UTC)[reply]

Hey thanks about that...That's what I've been thinking about so far...I better take small amount of intake regularly instead of starving and sure it all goes toward a positive way...Thanks again friends...

It's best to have a healthy diet AND exercise. --Proficient 17:45, 4 September 2006 (UTC)[reply]

Insect

I believe that this is a insect belonging to the Dermaptera order, but perhaps someone can tell what family or species is it? --Andreas Rejbrand 10:15, 3 September 2006 (UTC)[reply]

Could it be an earwig ? StuRat 10:27, 3 September 2006 (UTC)[reply]

I thought I said that :) Earwig = the Dermaptera order --Andreas Rejbrand 10:41, 3 September 2006 (UTC)[reply]

Having found the insect in Sweden, perhaps it is a Forficula auricularia? --Andreas Rejbrand 19:22, 3 September 2006 (UTC)[reply]

Circumstances for watching polarized light

Hi, I live around 65 North, are my chances for getting a view of Haidinger's brush better or worse than someone living further south? I also understand from the article that there are TWO brushes, each 90 degrees away from the sun. There isn't any at 180, then? The brush sounds really awesome, I can't wait to gaze into the sky for minutes and minutes, like a moron, with all my friends wondering what I'm doing. :) 81.93.102.35 10:53, 3 September 2006 (UTC)[reply]

If your aim is to just see a Haidinger's bush, it's much easier to see on a TFT screen then in the sky. I've seen a very good webpage on it, I'll try to dig up its address. – b_jonas 17:17, 3 September 2006 (UTC)[reply]

Anyway, I doubt that there are two brushes each 90 degrees away from the sun because the position of the bush depends on where you're looking at. – b_jonas 17:19, 3 September 2006 (UTC)[reply]

I don't think Latitude makes much difference. In Seattle I see Haidigener's Brushes all the time. It's best towards evening when the band of sky-polarization occupies the zenith. If not at sundown, you'll have to stare at the dark band of sky which is 90deg away from the sun. The brushes look like a wide bow-tie shape, with two yellowish quadrants and two bluish quadrants. Also, it's much easier to see the brushes if one stares straight up and then spins around. That way the brushes appear to be rotating, and you won't just seem questionable for staring upwards, you'll instead look like a complete fool. :) --Wjbeaty 00:49, 9 September 2006 (UTC)[reply]

STI's

If you either of your parents has an STI before you're born, excluding HIV, could you get it after your born? Please respond on my talkpage: user:100110100. Thanks!68.148.165.213 12:45, 3 September 2006 (UTC)[reply]

Sure, see congenital syphilis, and why do you think silver drops were routinely put in the eyes of newborns for most of the last century? To prevent gonococcal opthalmia neonatorum. Chlamydia trachomatis as well can be transmitted during delivery and cause infant conjunctivitis and bronchiolitis. Oh, and don't forget congenital herpes. And sorry we do not email private answers. alteripse 13:02, 3 September 2006 (UTC)[reply]

Thank you for your response. No, I have an account on Wikipedia. That's what you type in the search box to get to my talk page, but thanks for your response. How do you know of you have a STI from your parent (within the context of the above)?68.148.165.213 13:47, 3 September 2006 (UTC)[reply]

You get tested for whatever the mother has. --liquidGhoul 13:55, 3 September 2006 (UTC)[reply]

An infant with a congenital STI has a variety of problems apparent in infancy. If you are an adult wondering if you "inherited" something like that from your mother decades ago, you have bigger problems than an infection. alteripse 16:38, 3 September 2006 (UTC)[reply]

But STI's do not necessarily change genes, nor does it affect the baby prenatally. Can't STI's show up after the baby is born? I.e., affecting a person after the person is out of the womb? Or tube, in the case of invitro babies?24.70.95.203 16:58, 3 September 2006 (UTC)[reply]

STIs can indeed affect the baby prenatally. Congenital syphilis is a prime example of this. The symptoms of prenatally/perinatally acquired STDs are not typically the same as the symptoms of primary infection. For example, if you were exposed to chlamydia during birth, you are more likely to get conjunctivitis or pneumonia than urethritis. And "test-tube babies" still go through pregnancy in the womb! InvictaHOG 18:23, 3 September 2006 (UTC)[reply]

Pardon my response, I didn't make it clear. What I meant is that some STI's do not affect the baby prenatally, SOME, not all.100110100 00:04, 4 September 2006 (UTC)[reply]

You are right, a baby can get exposure to HSV2 during delivery and not develop disease. It is perhaps a matter of semantics whether you call that "getting it". Certainly it may take days or weeks for real trouble to develop (like herpes encephalitis. If you are asking if it seem healthy and can incubate for years and decades before the infection causes problems, we don't think so, or at least it is very rare or cannot be recognized as a congenitally acquired STD. HIV is about the only exception I can think of to the general rule that congenitally acquired STDs either cause trouble in early infancy or not at all. alteripse 00:25, 4 September 2006 (UTC)[reply]

Thanks for the response. Ok, can you get a get HSV2 during delievery\prenatally but be a carrier, or for a lack of better words, be able to infect other people, without showing any symptoms, even 'till the day you die'? I know that HSV2, you get get anywhere. Ok, I'll explain my situation. My parents never tested themselves for STI's and they still haven't. I am a virgin. But from the wikipedia article Herpes simplex virus, it says you can can it anywhere, & from what I garner from my talk page, InvictaHOG says that you can get HSV2 and NEVER display symptoms even by the time your dead [And come to think of it maybe even after your dead. Am I right?]. From this information, I just want to stay away from people. But that's so inconsiderate. So maybe as much information you guys could provide would be greatly appreciated. Thank you.100110100 07:13, 5 September 2006 (UTC)[reply]

I do not understand your concern. The world is full of viruses and we have all been exposed to a variety of them and carry some of them within us. I think the last sentences of my second and third answers apply here and are the limits of my expertise on this topic in this forum. You have given no reason for your fear that you are infected, and if so, that it came from your conception, gestation, or parturition. Before you make renunciations of close physical relationships for the rest of your life, pay a visit to an infectious disease consultant with expertise in virology to explain your fears and get reassurance. It might cost you a trip to a big city and $300 but if it settles this fear for you it is cheap at the price. If the infectious disease consultant assures you your fears are groundless, but you still can't shed them, a therapist will be a bigger expense and effort but might still be worth it. Don't make important decisions based on what a bunch of random guys here know ex vertice. Good luck. alteripse 10:42, 5 September 2006 (UTC) PS Either of these might be places to start based on your IP location: [13]. I think your best choice would be the pediatric inf dis dept at your local medical schood/children's hospital because those are the doctors with the most expertise in perinatal transmission; the UAlberta fellowship info says one of the 4 attendings specializes in virology. Alternatively: [14] but I would confirm ID board certification and virology interest before making appt. And it will be a lot cheaper in canada.[reply]

HSV 2\HSV-2

Can you have HSV 2\HSV-2 and never display symptoms? Please respond on my talkpage: user:100110100. Thanks!68.148.165.213 13:44, 3 September 2006 (UTC)[reply]

HSV 2\HSV-2 = herpes simplex virus 2\herpes simplex virus-224.70.95.203 17:10, 3 September 2006 (UTC)[reply]

Yes InvictaHOG 18:20, 3 September 2006 (UTC)[reply]

Ever in you life? Thanks.100110100 23:29, 3 September 2006 (UTC)[reply]

Ok, sorry let me rephrase my question: Must you display at least A symptom of HSV 2 [or otherwise called herpes simplex virus 2, herpes simplex virus-2, or HSV-2] in your lifetime, [i.e.: before you die] if you have HSV 2 [or otherwise called herpes simplex virus 2, herpes simplex virus-2, or HSV-2]?100110100 00:09, 4 September 2006 (UTC)[reply]

Why does this edible oil mixture taste bitter?

Recently I bought a mixture of flax seed oil, sunflower oil, olive oil, evening primrose oil, soya lecithin, and rice bran oil. It is supposed to give a balanced amount of Omega 3, 6 and 9, but I just bought it as it was a cheap way of buying non-fish omega 3.

I know that Flaxseed oil tastes or smells like putty, because that's what putty is made of, but it also had an unpleasant bitter taste.

Interesting. --Proficient 17:46, 4 September 2006 (UTC)[reply]

I have previously eaten all the ingrediants separately except Evening Primrose Oil and Rice Bran Oil, and none of them tasted bitter, nor are they mentioned as being bitter in Wikipaedia.

Thanks

Some of these oils (e.g. olive oil and flax seed oil) contain polyphenols such as tannin, which taste bitter to the human tongue. Maybe some of them were masked in their original states and activated through the mixing process. (Or maybe the mix uses unbalanced bitter-tasting products to begin with).---Sluzzelin 14:11, 3 September 2006 (UTC)[reply]

Bicycle seatpost has rusted into frame

Can anyone suggest the best way to remove the seatpost please? I do not mind destroying the seatpost, but not the frame. Thanks.

Is the post or the frame rusted? The best method I can think of (not as any sort of expert is to remove the seat and drop down something that will catch at the end, then pull and rotate. Good luck. --\/\/slack (talk) 15:02, 3 September 2006 (UTC)[reply]

Try a pipe wrench and twist the post, might work if it isn't totally rusted and the worst thing that can happen is you'll mangle the top of the post, which you don't want anyway. If that dosen't work you could try getting a machinest to drill it out, but I'm not sure how well that would work and there is a good chance you would wreck the frame. The only other option I can think of would be to get a bicycle shop to heat up the frame so that it expands and the post can be removed. My father had this done when his crank rusted into the frame and it didn't seem to affect the steel frame's strenth, though it did a job on the paint. Still there is risk there as well. It's also probably wise to think about the rest of the bike before you do something pricey too, is the rest of the bike worth keeping or not? That probably isn't the only thing that has rusted on it. I had this problem on an ancient racing bike that I got for free. The post is still in there, the rest of the bike wasn't worth the repair. 24.137.78.34 15:10, 3 September 2006 (UTC)[reply]

From WD-40: "Two rules get you through life: If it's stuck and it's not supposed to be, WD-40 it. If it's not stuck and it's supposed to be, duct tape it." :-) Maybe a combination of WD-40 and vise grips? Weregerbil 15:13, 3 September 2006 (UTC)[reply]

Some bicycle mechanics will remove the cranks and bottom bracket, turn the frame upside down, pour motor oil into the seat tube through the bottom bracket shell, and let it sit for a day or two, then apply some torsion to the seat post. Sometimes, the seat post lug can be slightly spread to facilitate dislodgement. At all times, one must use a combination of force and restraint so that the frame is not damaged. Because this often takes experience, you might consider having a bicycle mechanic do this task if your initial attempts are not successful.--Mark Bornfeld DDS 16:24, 3 September 2006 (UTC)[reply]

I would either take Mark's suggestion (you might improve on it with rust eater (dunno the english term)) or if that does not work, you should be able to either drill the seatpost out completely (you will need to fixate both the bike and the drill) or to drill a small hole down along the seatpost so you can 'fold' it into the bike frame. Another way would be to get a winding drill and create a screw thread into which you screw (and perhaps even glue it in with strong loktite (the kind for large ships) or some such) a bar with a handle. This should give you _lots_ leverage. RichiH 17:22, 3 September 2006 (UTC)[reply]

My solution would be: spray some WD40 into the crack. Leave for 24 hrs. THen, get a pair of Mole grips, tighten hard and give stem a twist. If no movement, gently tap the end of the grips with hammer. I still noemovement, spray more WD 40 and leave for another 24 hrs. Repeat process until stem is loose. 8-)--Light current 18:12, 3 September 2006 (UTC)[reply]

Although I'm in complete agreement with the utility of WD-40, in this case, a specific penetrating oil (American trademark: "Liquid Wrench") may work better for this than WD-40. Give it lots of time to work its way along the seat post, though. (And I mean lots, I'm talking several days or more.) And yes, let gravity work it down and then flip the bike and let it flow up, err, down from the bottom bracket. I also agree with whoever suggested lots and lots of torque/a pipe wrench.

Atlant 22:48, 7 September 2006 (UTC)[reply]

complex carbohydrates

finally, after clicking all over the place I get here. Question: May I please have a list of complex carbohydrates? I am diabetic, and controlling it with diet and exercise. I want a simple list of foods that are considered complex carbohydrates. Thank you Linda Johnson

The American Diabetes Association and Diabetes UK give you a summary. Though the lists posted here aren't all too comprehensive, the websites might point you to further information. ---Sluzzelin 14:51, 3 September 2006 (UTC)[reply]

Complex carbohydrates is in cookery another name for starches. For example, rice, pasta, bread, potatoes, beans. See Starch#Starches_as_food. The wholemeal kinds are to be preferred. I would not eat bananas even though listed as a starch - I expect they have a lot of sugar in them also.

You may also be interested in the articles Diabetic diet, Diabetes management, Diabetes, and low Glycemic index foods, including List of foods with a low glycemic index.

This site http://www.netdoctor.co.uk/focus/nutrition/facts/lifestylemanagement/carbohydrates.htm has a list of complex carbohydrates:

bananas

barley

beans

brown rice

chickpeas

lentils

nuts

oats

parsnips

potatoes

root vegetables

sweet corn

wholegrain cereals

wholemeal breads

wholemeal cereals

wholemeal flour

wholemeal pasta

yams

There seems to be a lot of medical quackery on the internet, so don't believe everything you read.

I do hope you are doing this under regular medical supervision - your sight is at risk if you are not. Take care. 81.104.12.75 15:14, 3 September 2006 (UTC)[reply]

Slow decrease in weight at sub orbital velocities

Hi, I know that the Concorde airliners flew fast enough to decrease the weight of the passengers from your article, and that at 7800 m/s one's weight is zero since it is orbital speed. I am wondering how fast the weight decreases in relation to speed. I realize that height also has something to do with it, but unless I am really off, this is not generally significant? Thank you for your patience. 24.137.78.34 15:01, 3 September 2006 (UTC)[reply]

It is not the speed at which it reaches altitude, it is the falling that get's you weightless I believe. — [Mac Davis] (talk) (Desk|Help me improve)

Let's see if I make a mess of the math...

The centrifugal force can be calculated with F=v²/r.

Concorde's cruising speed is(was) 2170 km/h = 603 m/s. Earth radius r=6372000 m (could add the plane's altitude but the effect is small). Flying east at the equator the Earth's rotation (465 m/s) adds to the speed: F = (603 m/s + 465 m/s)² / 6372000 m = 0.179 m/s². This is about 1.8% of Earth normal gravity (9.78 m/s²) so a 100 kg person would weigh 1.8 kg extra. Flying west you need to subtract the velocities, giving 0.00299 m/s², i.e. a very tiny difference (Earth rotation and plane speed almost cancel each other out).

Hmm, the Concorde article quotes 1% and 0.3% weight differences. I'm guessing the article assumes Europe to US flight rather than equatorial flight which I used. Earth rotational speed of 200 m/s gives 1% and 0.3%; I'll bet the article assumes a London/New York flight.

At the speeds of an X-15 you'd be 10% lighter.

Thank you very much, that was exactly what I wanted to know. I did not know that the centrifugal force equation could be used to calculate it, though it makes a lot of sense now. 24.137.78.34 20:19, 3 September 2006 (UTC)[reply]

Nikon D70 question

Hi Wickies

A quick one for ya

I have a Nikon D70 camara and did some long exposures the other night which resulted in a purple "fog" in the top right of the picture on any exposure over about 3 mins. I thought it might be some sort of light pollution so I put the camara in a dark bag with the lense cap on and tried several exposures of differing lengths from 3 to 10 mins. The purple fog persisted in the top right of each exposure. The longer the exposure the further the purple fog drifted across the picture. Any ideas what it might be? Me being a bit of a thick'o when it comes to electronics means I ain't got a clue other than thinking that something must be energising the top right (or bottom left?) corner of the photo sensor. Anyone had this problem with a digital camara before?--Eye 16:33, 3 September 2006 (UTC)[reply]

This explains the noise fog. [16] You can apparently map this into the camera for noise reduction. --Zeizmic 22:21, 3 September 2006 (UTC)[reply]

And if the camera can't do that, use one of those bagged shots in Photoshop and substract it (can't think from the top of my head how to do that, but it's possible and in other applications too probably). Ideally, you should have one for each exposure duration, but using a long one and varying the amount of substraction should also work. DirkvdM 07:42, 5 September 2006 (UTC)[reply]

Spiral path of a Hawk

What advantage does a hawk/an eagle get, when it follows a logarithmic spiral instead of an Archimedean spiral-while diving on it's prey ? Thanking you,--Pupunwiki 16:39, 3 September 2006 (UTC)[reply]

I read something about this in Mario Livio's book "The Golden Ratio." He seems to suggest that it has to do with optimizing energy. The bird, while following a particular spiral path, is able to keep its eye on the prey, while at the same time maximizing its own velocity. - R_Lee_E

(talk, contribs) 16:52, 3 September 2006 (UTC)[reply]

Sidenote - From what I've gathered, Livio's thesis is to show that the reason we find the logarithmic spiral (or golden spiral) present so frequently in nature (i.e. galaxies, sunflowers, the flight path of birds of prey, etc.) can be explained in terms of energy conservation, or energy optimization. For instance, Livio shows that the reason why the golden mean makes an appearance in the sunflower ([17]) is because it allows for the maximum amount of sunflower seeds to be packed into the smallest area - thus making the most efficient maneuver possible with the energy at its expenditure. A similar phenomenon is seen in the stemgrowth of most plants, wherein each ascending leaf grows according to the golden mean. This is to help prevent the lower leafs from being shaded by the leafs directly above them. The 'golden mean' itself seems to be a kind of sweetspot in nature. Various processes within nature, whether living or non-living, seem to 'settle into' the golden ratio 'groove.' - R_Lee_E

(talk, contribs) 21:06, 3 September 2006 (UTC)[reply]

(sigh) The obvious spirals in a sunflower are not logarithmic: the angle between the spiral and the radius approaches a right angle, until at some point that series of spirals fades out and is replaced by the next. [18] [19] Nor is there any necessary connexion between logarithmic spirals and the golden ratio. —Tamfang 22:44, 3 September 2006 (UTC)[reply]

No connection between the logarithmic spiral and the golden ratio? Golden spiral "In geometry, a golden spiral is a logarithmic spiral whose growth factor b is related to φ, the golden ratio." - R_Lee_E

(talk, contribs) 22:55, 3 September 2006 (UTC)[reply]

No necessary connexion, I said. Yes, you can find a special logarithmic spiral whose constant is the golden ratio (or any other real number ≥1), but I'm forever seeing all log.spirals sloppily called "golden" or "Fibonacci" and it's best to avoid encouraging that. —Tamfang 06:24, 4 September 2006 (UTC)[reply]

It has been claimed that dogs, to catch a frisbee, like baseball players catching a ball, maintain an optical constant angle: How Dogs Navigate to Catch Frisbees. Indeed, if you miss the frisbee/ball and it zooms just past you, the angle will change quickly. It follows that if the angle doesn't change it cannot zoom just past you. Either it hits you (and hopefully you catch it), or it is not approaching. The same strategy may be followed by the diving bird. In a plane, with a stationary target, this implies a logarithmic spiral: the angle between the tangent vector and the vector to the centre of the spiral is constant. I'm not sure what it means in a 3D context. --Lambiam ^Talk 02:55, 4 September 2006 (UTC)[reply]

drawing molecules

what software do people use on wikipedia to draw and upload the png's of molecules like styrene?

The note on Image:Styrene.png indicates it was drawn with ChemDraw. Images are uploaded with any web browser.- Nunh-huh 17:38, 3 September 2006 (UTC)[reply]

An excellent free software is ACD ChemSketch [20]. --Andreas Rejbrand 20:31, 3 September 2006 (UTC)[reply]

600/1000V

I should know this but am ashamed to say I dont. What does 600/1000V mean when marked on single electric cables?--Light current 18:33, 3 September 2006 (UTC)[reply]

Cables are marked with all sorts of things. This voltage is the rating of maximum voltage that the wire can hold, and you can hold it in your hand. This is usually welding cable (600 V). All you would want to know is here. [21] --Zeizmic 01:21, 4 September 2006 (UTC)[reply]

I could not find the meaning in that source of the 600/1000V rating. Why are there two numbers and a slash? Does it mean that the maximum voltage is (600/1000)V = 600mV? --Lambiam ^Talk 03:03, 4 September 2006 (UTC)[reply]

Neither could I. Ive seen it on British cables and that ref was for US underwriters labs. So it may be specific to Europe or just UK. The voltage rating is either 600v or 1000v obviously under different conditions. What are those conditions?--Light current 03:10, 4 September 2006 (UTC)[reply]

I would guess 600v when enclosed (eg in a duct with other cables) and 1000v when laid in the open.--Shantavira 06:59, 4 September 2006 (UTC)[reply]

I believe the first number is maximum voltage between wire and ground, and the second number is maximum voltage between two wires.[22][23]. Weregerbil 12:02, 4 September 2006 (UTC)[reply]

Ahh thats it! Thank you!! I thought it had to be something simple--Light current 12:51, 4 September 2006 (UTC)[reply]

So its probably single phase against 3 phase. Notice 1000 = 600 x sqrt(3) (approx). I wonder if this applies to all the other dual voltage specs.--Light current 13:30, 4 September 2006 (UTC)[reply]

600 watts/1000 volts perhaps? --Proficient 17:47, 4 September 2006 (UTC)[reply]

I dont really think so!--Light current 00:45, 5 September 2006 (UTC)[reply]

An extract from BS 6231:2006 Electric cables. 600/1000 V PVC insulated cables for switchgear and controlgear wiring here (BS=British Standard) says that 600/1000 V cables are "intended for use at alternating voltages not exceeding 600 V to earth, and direct voltages not exceeding 1000 V to earth". It's puzzling that the ratio between the two numbers is not √2, but perhaps this is to allow for distorted power waveforms that have higher crest factors than pure sine waves. --Heron 20:47, 4 September 2006 (UTC)[reply]

So now we have two contrdictory stories. One from BSI and one from a US cable manf. So obviously these markings do not mean the same here as they do in the US!--Light current 00:50, 5 September 2006 (UTC)[reply]

600/1000V shows that the cable is a Trirated Cable, rated by CSA and UL to 600V and BS6231 to 1000V. [24]

Question about getting fluids Intravenously

I've tried to read Intravenous therapy, but if the answer is there, it's either been added since I last checked, or I didn't understand it. What I'm wondering is, in as basic terms as possible, how does the body accept fluid in an IV? I can understand drugs, cause those are supposed to be going in the bloodstream, and get there whether taken orally or any other way. But I'm just talking about fluids, like for dehydration. I'm sure (I guess) that when you drink water, some of it goes into the blood, but surely not all of it, the rest.. comes back out. Yet if given water (or, water/solution, whatever it is they actually give you) in an IV, it somehow still ends up being excreted. How does it not just all end up watering down the blood, but actually gets everywhere it needs to go, as it would from the stomach? -Goldom ‽‽‽ ⁂ 20:10, 3 September 2006 (UTC)[reply]

in the drinking case, the water that comes back out comes out via the bloodstream, after being absorbed from the small intestine and then collected at the kidneys. so when you get drugs by iv, you simply cut the intestines out of the loop, and pee out the excess as normal. Xcomradex 21:36, 3 September 2006 (UTC)[reply]

I think you have a basic misunderstanding of how water is distributed normally. The way it gets from the intestines to everywhere else is via the bloodstream. That is, it gets absorbed thru the intestinal walls into the bloodstream, then is delivered to the individual cells via capillaries, and is then absorbed thru the cell walls. Excess water is absorbed from the bloodstream by the kidneys and the excreted as urine. The only parts that may be dried out as a result of getting all your fluids intravenously are within the digestive tract. While your body has some capacity to keep the mouth and digestive tract moist with saliva and mucous (generated using water from the bloodstream), this capacity can be reduced by certain conditions or medications. If this method is reduced and liquids are no longer consumed normally, dry mouth can occur. For this reason, nurses will frequently dab the mouth with moist swabs or give the patient ice chips (if they are awake), to alleviate dry mouth. StuRat 22:26, 3 September 2006 (UTC)[reply]

Also, eating food but not drinking any fluids would be bad, causing constipation. Fortunately, if a patient is not allowed or able to drink fluids, then they aren't allowed or able to eat, either. StuRat 22:31, 3 September 2006 (UTC)[reply]

TFTs v CRTs

How reliable are TFTs now? Are they as reliable as CRTs?--Light current 20:53, 3 September 2006 (UTC)[reply]

I doubt it, you can have CRTs which are over 20 years old. I doubt that TFTs can last that long. --liquidGhoul 23:40, 3 September 2006 (UTC)[reply]

Any ideas how long TFTs last?--Light current 23:55, 3 September 2006 (UTC)[reply]

Shouldn't CRTs last pretty much forever? I know that TFTs don't, but not for how long. I remember reading about organic LCD screens, the are supreme in all areas concerning the picture, but they die in a few years. — [Mac Davis] (talk) (Desk|Help me improve)

Not for ever. See [25] 01:59, 4 September 2006 (UTC)

My Sony GDM FW-900 CRT (a pretty expensive one) died after three years, just after the Sony waranty expired. I had to resort to legal threats (based on the EU legal waranty) to get them to replace it. DirkvdM 07:48, 5 September 2006 (UTC)[reply]

Yes but was it the tube itself that failed? THats what im asking about--Light current 19:46, 6 September 2006 (UTC)[reply]

Fructose - how much is too much?

The fructose article says that eating fructose has some negative effects. How much is too much? How many apples is too much, so to speak. Thanks// Jack Daw 20:53, 3 September 2006 (UTC)[reply]

The question is equivalent to asking how much sugar is too much. It depends on your age, size, metabolism, activity level, other carb intake, etc. It does appear to contribute more to obesity than an equivalent amount of glucose. alteripse 00:18, 4 September 2006 (UTC)[reply]

One politician over here in Sweden reportedly eats 30 apples a day, he's 60+ I'd suppose, quite fit for his age and looks generally healthy. Got me curious... Jack Daw 13:30, 5 September 2006 (UTC)[reply]

Fructose is after all, just sugar. As I say, it is not the substance that is toxic, it is the dose. — [Mac Davis] (talk) (Desk|Help me improve)

That's the layman's answer, Mac. The advanced answer is that a mole of fructose may be more harmful than a mole of glucose, because fructose raises uric acid levels (which reduces hepatic sensitivity to insulin) in liver cells, may not be detected as well as glucose by the satiety and metabolic homeostasis neurons in the hypothalamus, and does not serve as an efficient insulin secretagogue in the pancreas. alteripse 01:06, 4 September 2006 (UTC)[reply]

Ahh! Fructose will kill us all!!! :) — [Mac Davis] (talk) (Desk|Help me improve)

PS: Sometime's it's the substance that's toxic, not the dose. Uranium for instance has no natural metabolic use in the body - it just sits there and zaps your cells until you get cancer. Any dose above zero is toxic. --bmk

(veering off topic) ... but see radiation hormesis.--Shantavira 07:08, 4 September 2006 (UTC)[reply]

BMK, well then you're in trouble, because you've been eating uranium as soon as you started to eat solid food. See the FDA. And your understanding of the risks uranium poses is way off; the stuff is much more chemically toxic than it is radiologically toxic (which isn't difficult, because its hardly radioactive at all). --Robert Merkel 00:48, 5 September 2006 (UTC)[reply]

September 4

Just been reading about SMART-1

Why are we humans so quick to crash high-speed objects into the surface of alien worlds without a single thought for the consequences in terms of it being seen as an act of aggression by potential natives?

You believe in the man in the moon, then? 8-?--Light current 00:13, 4 September 2006 (UTC)[reply]

Absence of evidence is not evidence of absence - maybe they're up there but they live deep underground. Maybe they think we suck already and this just confirms it. I think we've done some very foolish things when it comes to space exploration - like sending out probes containing data which would allow any potentially hostile alien species to pinpoint the exact location of our homeworld. --84.68.214.65 00:20, 4 September 2006 (UTC)[reply]

The Voyager/Pioneer probes are the least of our worries. Space is *big* and the chances of them being intercepted and picked up by a passing interstellar spacecraft are very, very, very small. Factor in the probabiliy that the aliens may be explorers, rather than conquerors and I wouldn't stress too much about that. We have, however been bleeding vast quantities of radio waves into space for the past century or so, basically turning the earth into a giant flashing 'something is going on here' beacon. Anyone/thing sentient and looking in the right direction within 100 LY or so already knows about us - and most probably knows *a lot* about us. --Kurt Shaped Box 00:33, 4 September 2006 (UTC)[reply]

Well theyd have to live deep underground to have survived all those impacts that the cratering shows has happened. And what do they live on, considering theres no water?--Light current 00:23, 4 September 2006 (UTC)[reply]

Maybe they live deep because it's warmer down there, nearer the core? Has it ever been proved that there's no water on the moon? --84.68.214.65 00:50, 4 September 2006 (UTC)[reply]

How did they get down there in the solid rock?--Light current 01:24, 4 September 2006 (UTC)[reply]

~~The only~~Usually, crashing is done by mistake. Everything else is simply a landing. AEuSoes1 01:27, 4 September 2006 (UTC)[reply]

Actually, the SMART-1 spacecraft appears to have been intentionally crashed into the moon at high speed so astronomers could examine the dust could. Wasn't something similar done with a probe ramming into Halley's Comet ? StuRat 01:37, 4 September 2006 (UTC)[reply]

The space mission I think you're talking about is Deep Impact, and the comet is 9P/Tempel. --Bowlhover 05:05, 4 September 2006 (UTC)[reply]

But that wouldnt bother the moon men at all surely: because they live under the surface! 8-)--Light current 01:49, 4 September 2006 (UTC)[reply]

Meteors hit the moon all the time, so the 'crash' would be a normal occurrence in that environment. (Then again, tropical cyclones are normal and they kill people - we'd be pretty upset if alien scientists created one artificially "just to see what it was like".) Peter Grey 02:07, 4 September 2006 (UTC)[reply]

Are you suggesting Hurricane Katrina was an attack on our homeland by an alien race that hates our democratic ideals? Lets launch a War on Extra-Terrestrial Terror, shall we? Rockpocket 06:15, 4 September 2006 (UTC)[reply]

As to the 'why', we don't think much about destroying life here on Earth at a massive scale, so 'we' don't realy give a shit. As to whether that's a nice thing to do, that depends on which chances you are willing to take. This reminds me of those Indian religious freaks who whipe the floor before them to prevent them stepping o bugs, which are, after all, also living beings. In the case of extraterrestrial life, the chances of that existing i na specific place are so slim that if we'd want to eliminate that risk, we couldn't do anything at all. Hell, we even accpet the death of half a million of our own kind each year for the sake of transportation. And those are deaths we know will happen and could even greatly reduce without much negative side-effects. And still we do it. As to whether it would be wise - would they retaliate? If we don't detect them they probably live on such a different level that they may not even know what hit them - jut like we think hurricanes are a natural phenomenen. DirkvdM 07:59, 5 September 2006 (UTC)[reply]

Beer-- why is it fattening?

Is it the alcohol, or the sugar/carbs, or both?--Light current 00:20, 4 September 2006 (UTC)[reply]

Beer is not really fattening at all. People tend to blame it on the beer when it is really the lifestyle that usually accompanies people who drink significant amounts of beer. i.e. sedentary jobless man that sit on the couch and watch tv all day lifestyle. — [Mac Davis] (talk) (Desk|Help me improve)

Are you really sure? I think its 200 cal /Imp pt It tends to make me put on weight.--Light current 01:14, 4 September 2006 (UTC)[reply]

The calorific content of drinks like vodka and rye come from acetate. Ethanol is converted to etanal and then acetic acid in a two step process in the body. Acetic acid is essentially a very short chain fatty acid (it doesnt have enough carbon to make it aliphatic, but it undergoes the same chemistry). As such alchohol has only slightly less biological energy content than vinegar. Also, the other ingredients in beer and other spirits, such as sugars and various organic matter, adds to the bottom line (and the waist line).Tuckerekcut 01:44, 4 September 2006 (UTC)[reply]

OK so its the carbs and the sugars that do most of the damage. But if you go for low sugar beer, it means it has more alcohol usually? And is the converse true?--Light current 01:52, 4 September 2006 (UTC)[reply]

Don't just blame the carbs--a shot of vodka (the regular stuff contains little more than ethanol and water) is ~50 calories. A pint of beer can run you 120-350 calories, depending on the brew. Mixers, of course, jack up the calorie content, too, as well as the greasy pub fare, and the following day's relative lack of activity (whilst battling a hangover) only makes the situation worse. Bottom line: total calories, in the form of sugars, fats, proteins or alcohol, is the most important number when watching one's diet, not the number of grams of carbs or fat. Net caloric balance is where it's at! Drink your beer! Just be sure to jog to the bar & back to help even things out! -- Scientizzle 02:35, 4 September 2006 (UTC)[reply]

It's only fattening when you don't use the calories you take in. -131.211.210.11 07:11, 4 September 2006 (UTC)[reply]

It is also a result of the food that tends to be eaten with beer - e.g., peanuts, pizza... BenC7 10:59, 4 September 2006 (UTC)[reply]

Well I tend only to eat 1 packet of peanuts per session and no pizza etc!. I tend to eat before drinking to try to protect the organs--Light current 12:57, 4 September 2006 (UTC)[reply]

Beer is not fattening. However beer is extremely energy dense. So when you consume beer, you get to your daily requirement of energy very quickly. And so your other consumption of fatty food, quickly turn into belly fat. Remember, belly fat comes from other fatty food and not from beer. Ohanian 22:13, 4 September 2006 (UTC)[reply]

Thats not true contrary to popular belief you do not have to ingest fat to become fat, fat is simply stored energy, though comprised of chemicals, that may not be available from the beer, the energy that needs storing is obtained from the beer. And so beer does make you fat. Philc _T^E_C^I 20:22, 5 September 2006 (UTC)[reply]

OK but its the same difference!` I consume the energy fronm the beer instead of from my food which then goes to make fat? Makes sense--Light current 22:21, 4 September 2006 (UTC)[reply]

War between humans and another species on another planet in the solar system?

Suppose that our constant 'crashing of stuff into their planet' annoys them and they decide to do something about it and declare war - in what form would such a war take place?

If we assume that the alien species lives on a reasonably close planet (let's say Mars for the sake of argument) and has a similar level of technological development to us, then wouldn't the 'war' actually be a bit of a damp squib? Both they and we would be reduced to using rockets to launch bombs/heavy objects at each other's worlds, which would take several months to reach their targets, leaving plenty of time for them to be detected and diverted/destroyed in space.

Yep - interplanetary war would be pretty boring without manned warships and/or long-range laser cannons. :) --Kurt Shaped Box 00:47, 4 September 2006 (UTC)[reply]

(fell asleep, edit conflict) Most astrophysicists and astrobiologists say that any civilization advanced enough to be able to proceed in interstellar warfare would not. Kind of a age=wisdom=pacifism thing. — [Mac Davis] (talk) (Desk|Help me improve)

If the Martians were smart, they'd launch a small pod filled with a selection of interesting local bacteria/virii at the earth without even initiating contact with us to declare war. That way, we'd never see it coming. Billions dead if they chose the right bugs. --84.68.214.65 01:05, 4 September 2006 (UTC)[reply]

Despite the War of the Worlds book, microbes from one planet are unlikely to be effective against life forms on another. In order to be effective parasites, microbes must be adapted to their hosts. StuRat 01:20, 4 September 2006 (UTC)[reply]

We've been sending spacecraft to Mars for years. Most of them were probably covered with human DNA. If there are any Martains, they're probably aware of our genetic code. To the Martians, suddenly having a bunch of alien probes descending from the sky would seem very threatening indeed. It would only be common sense for them to examine the probes for evidence of their origin and for information about the species that sent them, just in case it became nescessary to defend themselves against an unknown enemy from space. Once you have DNA, you can figure out nasty things to do to the creatures that bear that DNA. --84.68.214.65 02:36, 4 September 2006 (UTC)[reply]

Really? You mean like the amazing success we - with "a similar level of technological development" - have had studying the DNA of influenza and the mosquito? And we know the fundamental basis of their genetic code and have them to test our "nasty things" out on. Rockpocke

Actually, all Martian probes are thoroughly scrubbed before liftoff so as to prevent contamination. It doesn't eliminate all microbes, but it certainly means that they're not "covered" in human DNA.AEuSoes1 21:05, 4 September 2006 (UTC)[reply]

t 06:10, 4 September 2006 (UTC)[reply]

And directed energy weapons like lasers would likely be ineffective because of the inverse square law. A more feasible scenario, perhaps, would be redirecting asteroids into collision courses with the Earth, particularly as ones made of ice make excellent nuclear rocket propellant. --Robert Merkel 01:28, 4 September 2006 (UTC)[reply]

Are you sure it would be so easy to detect a nuclear missile? Terrestrial warning systems look for launch plumes, and we've got it easy because the launches are so close. If Mars launched a ballistic missile at us, we wouldn't see the launch, especially if they were clever enough to do it on the far side of the planet. And a missile is orders of magnitude smaller than some of the asteroids we periodically discover in the neighborhood, so we wouldn't be able to see it once its motor went dark. Our only warning method would be to insert surveillance satellites into Mars orbit and hope they don't shoot them all down. Melchoir 02:06, 4 September 2006 (UTC)[reply]

Don't we have some sort of system already in place that routinely scans an area of space around the earth for objects and tracks them (radar based?)? I don't know what it's called but I've seen it on the news - they use it to locate and keep tabs on pieces of debris from our spacecraft that may be hazardous to future missions. Wouldn't that detect anything on a collision course with the planet? --Kurt Shaped Box 02:19, 4 September 2006 (UTC)[reply]

Yes, but anything coming from deep space at very high speed may not be detected in time to do anything about it (though of course the faster it goes, the more shielding you'd need to get it into the atmosphere, and the easier to detect it would become). However, one might suppose that missile defence technology might have improved somewhat by the time this becomes an issue. --Robert Merkel

What if the martians launch several nuclear bombs in quick succession, each one targeting a different place on Earth? I'll be surprised if anyone detects the bombs before they get extremely close (like within 1000 km), because SMART-1 was only magnitude 19 when it was orbiting the Moon. I'll be even more surprised if anybody can intercept an interplanetary spacecraft that doesn't want to be intercepted. There's hundreds of billions of metres between Earth and Mars, and a spacecraft is at most only several metres in size. --Bowlhover 04:21, 4 September 2006 (UTC)[reply]

We'll have at least enough time to launch the same sort of barrage back at them, ensuring ourselves the last laugh. Dead. freshofftheufo ΓΛĿЌ 05:44, 4 September 2006 (UTC)[reply]

I think it's clear at this point that our only self-defense option is to pre-emptively bomb the tar out of the planet as soon as possible. With any luck it'll send a strong message to the Asteroid Belt, too. Melchoir 07:09, 4 September 2006 (UTC)[reply]

No need to worry about the Asteroid Belt, the Martians already blasted them. :-) StuRat 08:22, 4 September 2006 (UTC)[reply]

So Astero was the solar system's version of Atlantis? DirkvdM 08:35, 5 September 2006 (UTC)[reply]

Probes that have been sent to other objects in space have to be sterilized (USA and USSR signed a treaty on that). Their biggest fear is to discover life on Mars... and then to be forever in doubt about whether or not it's not from our own planet. However, the Mars 2 and Mars 3 in 1971 from the USSR are said to have been poorly sterilized or simply not sterilized. But why would an alien race declare war upon an unknown (and possibly much stronger) species for just a dozen of probes on their entire planet?Evilbu 21:51, 4 September 2006 (UTC)[reply]

Imagine if alien probes of unknown origin started landing at various points on the earth's surface and regular intervals, taking readings/samples, then transmitting data offplanet. Provided that the governments of the world didn't manage to successfully cover it up, humanity would literally be *shitting* itself, due to fear of the unknown - "there is something out there that is interested in us and we don't know why!". You can bet that the military would have their best brains trying to figure out where the things were coming from, how they worked, what exactly they were doing, the technology involved in their manufacture, and coming up with possible strategies for defense of the planet in case the probes were only a prelude to something much bigger. A pre-emptive attack against the alien homeworld would certainly be an option raised at the meetings - "humanity must prevail at all costs", "violation of our territory by forces of unknown intent", "the enemy may walk amongst us at this very moment", "violence in self-defense", etc. --Kurt Shaped Box 23:43, 5 September 2006 (UTC)[reply]

In the history of mankind if two cultures met one easily overpowered the other because they were more technologically advanced. In the case of species from different planets, that would also likely be the case, just to a larger extent. So either they are very inferior to us, in which case they couldn't do anything, or they would be very superior to us, in which case they would have technology even we at the ref desk don't know about (assuming we're all humans - over the Internet you never know who's at the other end). So the question is unanswerable.

Another approach is to compare it to conflicts between different species here on Earth. We like to think we're superior to bacteria, but we rarely mange to stop them making us sick. So maybe the term 'superiority' doesn't apply if the species are too dissimilar, which they are likely to be in the case of species from differnt planets. Maybe we'd even be unaware of each other and consider what happened to be a natural disater or (more literally) an act of God. DirkvdM 08:35, 5 September 2006 (UTC)[reply]

"Most astrophysicists and astrobiologists say that any civilization advanced enough to be able to proceed in interstellar warfare would not. Kind of a age=wisdom=pacifism thing" — another example of why physical scientists don't make the best moralists or politicians. They also thought that after World War II, life would just be peaches and cream since nuclear power and nuclear weapons would ensure that everyone would learn to love their brother. Reality was a little messier. --Fastfission 14:36, 5 September 2006 (UTC)[reply]

Abingdon Island tortoise

Since this species is nearing extinction, and there is currently only a single individual left (a male named "Lonesome George"), could it be cloned to continue the species ? Also, if male turtles have an XY chromosome pair, I would think that two X's could be taken from two cells, and the Y discarded, to clone a female from the male. A female of a similar species could be drafted as a surrogate womb, and the embryo implanted surgically (sorry if this is the wrong terminology for an egg-laying species). Is there any reason this wouldn't work ? I do realize the lack of genetic diversity would not be ideal for the species, but think it would be infinitely better for the species than extinction. StuRat 01:12, 4 September 2006 (UTC)[reply]

The whole reason for sex (comments allowed) is to correct for genetic error. Sometimes the errors are good things, but mostly not. Even if there were both a male and a female, it would be difficult to keep the species going because of the lack of genetic diversity. Still, if they can clone dogs... --Zeizmic 01:30, 4 September 2006 (UTC)[reply]

I guess a good question here would be, have there been any reports of clones being able to give birth? freshofftheufo ΓΛĿЌ 05:40, 4 September 2006 (UTC)[reply]

Sure, Dolly the sheep had kids (well, lambs, actually), and plenty of cloned mice have reproduced. Rockpocket 05:45, 4 September 2006 (UTC)[reply]

I actually checked that article (and others) to make sure before I asked. There's no mention in it of her lamb, though I see now it mentions it in the picture. Bah. freshofftheufo ΓΛĿЌ 14:01, 4 September 2006 (UTC)[reply]

I would say your proposal is theoretically possible using current technology, though it would be very challenging and thus improbable. The inefficiency of cloning such a poorly studied animal notwithstanding, there are a few complicating factors. Harvesting different chromosomes from different cells during mitosis, then reconstituting them for successful nuclear injection could be tough. Using a difference species as a host would also complicate matters (consider Mitochondrial DNA). Overall, the track record for cloning of endangered species is not good. Rockpocket 06:02, 4 September 2006 (UTC)[reply]

I'm not sure we have the technical capability to extract single X chromosomes from XY pairs and use them to form XX pairs. --Lambiam ^Talk 06:43, 4 September 2006 (UTC)[reply]

Picking two Xs from metaphase spreads and chucking them back together in a tube with the rest of the autosomes wouldn't be too difficult, i would have thought, with the right equipment. Making sure it viable for nuclear injection is a different kettle of fish, however. Rockpocket 07:10, 4 September 2006 (UTC)[reply]

How big is the turtle? Where does it come from? What is the cause for extinction? The best chance for this species is finding a remnant population. It would not work to clone the current turtle, cloning technology is not that advanced as to save a species in such a poor state (and I doubt any state). --liquidGhoul 06:49, 4 September 2006 (UTC)[reply]

It's a giant Galapagos Tortoise of the species Geochelone abingdoni. I believe that the sole remaining member of the species was moved to the Charles Darwin Research Station in the Galapagos Islands, after the remainder of the population was wiped out on Abingdon Island (one of the Galapagos), due to introduced species (such as rats, which ate their eggs). StuRat 08:10, 4 September 2006 (UTC)[reply]

Damn, then the chances of a remnant population are remote. I was hoping it was a small turtle from the Amazon or something. The Geochelone article doesn't mention this species, are you sure you have up-to-date taxonomy? --liquidGhoul 14:18, 4 September 2006 (UTC)[reply]

The article is at Lonesome George which says he is of a sub-species: Geochelone nigra abingdonii. Rmhermen 02:18, 5 September 2006 (UTC)[reply]

Upon reading that article, there sounds like there is some hope for finding another specimen. There are hundreds of Galapogos Tortoises around the world, some of them would predate the introduction of whatever killed them. Hell, Harriet was caught by Darwin, anything is possible. Genetic testing needs to be done to find another of the same subspecies. --liquidGhoul 07:34, 5 September 2006 (UTC)[reply]

Tracking down original references

Hi

I was wondering if there is a good way to find original references - the kind of reference that lets you say "X was discovered by Y in Z (Ref 1.). Any suggestions? If you happen to know, off the top of your head, how cytochalasin B, phloridzin, pholeretin or wartmannin were discovered,that information would be great! Thanks everyone!

Aaadddaaammm 06:37, 4 September 2006 (UTC)[reply]

yeah i've seen one of those things, its big and rectangular, and has "library" written on the front ;-) more seriously, you could probably find phloridzin and pholertin in a review somewhere, or on SciFinder if you are lucky enough to have access. Xcomradex 06:55, 4 September 2006 (UTC)[reply]

PubMed is your friend. If you query "cytochalasin" and look among the earliest references, you will find what you are looking for. This paper states:

The cytochalasins are metabolites of moulds that have been recently isolated by Dr W. B. Turner, who was also one of the group that described the chemistry of these compounds (Aldridge, Armstrong, Speake & Turner, 1967). Their special importance lies in their property of inhibiting cell division by blocking cytoplasmic cleavage. Such compounds are of value in the study of cellular function and these particular substances are unique in their ability to block cell division without preventing mitosis. Four cytochalasins have been isolated from culture filtrates: A and B from Helminthosporium dematioideum and C and D from Metarrhizium anisopliae.

The reference: ALDRIDGE, D. C, ARMSTRONG, J. J., SPEAKE, R. N. & TURNER, W. B. (1967). The cytochalasins, a new class of biologically active mould metabolites. Chem. Commun. 1, 26-2.

If you follow a similar process you should find the history of the other compounds also. Rockpocket 07:02, 4 September 2006 (UTC)[reply]

Awesome! Thanks very much for all your advice. I'll let you know how I get on. Aaadddaaammm 07:09, 4 September 2006 (UTC)[reply]

Scientist - Enrico Fermi

Did Enrico Fermi have a middle name? My son is doing a research project, and his teacher insists that the project not be turned in without the person's middle name. We have researched numerous sources and have not found a middle name for Enrico Fermi on any source. Thank you very much.

Enrico Neutrino Fermi? Your son's teacher needs a vacation. Not everyone has a middle name. The 'S' in Harry S. Truman, for instance, doesn't signify a middle name and was added for the sole purpose of having a middle initial. ---Sluzzelin 13:38, 4 September 2006 (UTC)[reply]

He/she already had one--it's summer vacation! And it still is for me. --Bowlhover 14:36, 4 September 2006 (UTC)[reply]

Doesnt look like he had a middle name--Light current 13:42, 4 September 2006 (UTC)[reply]

Wow. That S in Truman I didn't know about. Interesting. --Proficient 17:49, 4 September 2006 (UTC)[reply]

...Jesus H. Christ...(--Shantavira 18:08, 4 September 2006 (UTC))[reply]

Does anybody but me find it mildly irritating when a history book insists on giving full names for the individuals they mention, even when the individuals in question never used some of the names in public? ColinFine 20:16, 4 September 2006 (UTC)[reply]

The Harry S Truman thing is not the version I've heard. Both his grandfathers had names starting with S, and his parents couldn't decide which one of them to honour in his middle name so they chose just the initial. That way, both granddads could say that they were looked after. Neat solution to a tricky family problem. JackofOz 01:09, 5 September 2006 (UTC)[reply]

Then there's the fictional, although interesting, way of solving the problem as was shown on the Dick Van Dyke Show with their son, Ritchie "Rosebud" Petrie. The letters in "Rosebud" each stood for a seperate family member's name. Ritchie was bummed about having Rosebud as a middle name until Rob and Laura explained to him that he in fact had seven middle names. But back to the point, no, I don't know Fermi's middle name if he had one. And IMO, the teacher is being silly for putting forth such a requirement. Dismas|^(talk) 07:56, 5 September 2006 (UTC)[reply]

What an amazingly pedantic teacher. Nothing like making children focus in on the unnecessary details (middle names?) to make them miss the big picture and get the absolute wrong impression about scholarship. You should leave a note for them that even historians of science honestly don't give a damn about someone's middle name. We prefer first names because of the narrative form of history, but there is no strict reason to require them (E. Fermi gives enough information to work with, even Fermi would be fine if there was context given). We don't even REALLY care about specific dates in most cases—if you can remember something to the resolution of a quarter of a decade, that's usually enough. History is not about pedantic details or specific facts, it is about being able to combine lots of small understandings into larger understandings, to really understand the causes for things and the contexts of them. And Fermi didn't have a middle name, no. --Fastfission 14:44, 5 September 2006 (UTC)[reply]

3d effects

Is it possible to create 3D efects with the help of the compouter screen?if not what extra hardware is required?

Origami — [Mac Davis] (talk) (Desk|Help me improve)

Are computer screens foldable now? - Rainwarrior 18:21, 4 September 2006 (UTC)[reply]

Well, yes. With 3D glasses of some sort, like the usual red blue ones combined with making a 3D scene in those colours on your screen. The Sega Master System had an interesting device for the game Space Harrier 3D which ran in synch with your screen, flipping one eye open and one eye closed at each frame and alternating display of the left and right views. - Rainwarrior 18:10, 4 September 2006 (UTC)[reply]

Also, there is the Stereogram or Autostereogram ("magic eye") kind of thing, which requires you to cross your eyes a little. That can also produce 3D effects. - Rainwarrior 18:21, 4 September 2006 (UTC)[reply]

LCD shutter glasses are a good way of getting full colour 3d images out of a computer screen. you need to buy the glasses and the sync box however, and you'll need to be using software that produces 3d data (eg. not wikipedia (yet)). Xcomradex 21:58, 4 September 2006 (UTC)[reply]

Philips has had 3D screens for quite some time now: [26]. --Lambiam ^Talk 22:34, 4 September 2006 (UTC)[reply]

MAGLEV

is it possible to make a maglev such that only permanent magnets counteract the weight and side to side motion and only energized ones control its velocity so as to attain full eficiency?

Yes it is but it would take alot of magnets for the track. THats why its not done.--Light current 13:35, 4 September 2006 (UTC)[reply]

Black-holes

What determines the schwarzchild radius of the black hole?

Its mass (only)--Light current 13:33, 4 September 2006 (UTC)[reply]

Just look at the formula given in the article. 2, G and c are all constants leaving m as the only variable.

bio project question

as i was looking 4 bio projects i came across this link , which described how to extract dna from green peas , im rather sceptical if this is true ,altough it looks like an university website, i think it is a prank. learn.genetics.utah.edu/units/activities/extraction/[27] my question is that is this experiment feasible , by that i mean when i tried it out i couldnt get the same results and i was wondering "is'nt dna soo small that it can't be seen with the naked eye?212.72.3.92 15:03, 4 September 2006 (UTC)[reply]

That's interesting. It looks real to me. When I did DNA extractions in intro bio in college, it was harder, but I think that's partly because we were using adult human cells, which as the FAQ for the Utah website explains, requires a centrifuge because the amount of DNA is smaller. An individual strand of DNA is tiny, but in principle there's no reason a bunch of strands stuck together wouldn't be big enough to see and handle. What I do wonder, though, is whether this procedure really separates out everything but nucleic acids themselves, or whether what you get at the end is something more like chromatin. (Also, we have an article on DNA extraction, but it needs work.) --Allen 16:34, 4 September 2006 (UTC)[reply]

(AFTER EDIT CONFLICT) Your link didnt seem to work for me, but my guess is that it described the rather simple marburg preparation of DNA by cold ethanol precipitation. Basically, if you put a whole lot of cells in your blender for a bit to crack them open (or alternatively use a chemical lysis method), and then put the resultant slush in to water, the DNA will dissolve in the water. If you then pour out a layer of very cold ethanol on top of the water so that there are two distinct phases, you can literally pull the DNA stands out of the water solution (and into the EtOH solution) with a scratched-up glass rod. The DNA is soluble in the water, but insoluble in the cold ethanol, so it will come out of solution as a sort of whitish clear stringy gunk. For the most part, this is DNA, with a bunch of other associated proteins. This is possible for two easily explainable reasons. First, the amount of DNA in a single cell is pretty large. If you were able to take the DNA out of a single eukaryotic cell and hold it as a piece of string, it would be about 2 meters long. It would only be a few atoms thick, and would break into millions of peices in the process, but you get the idea that it is pretty big nonetheless. To package this DNA into a cell takes many many recursive packaging mechanisms, and some of these are destroyed by the lysis/precipitation process, making the DNA more bulky than it would be in situ. The other thing to consider is that everything is made up of tiny things that are invisible to the naked eye. Even though a single copper molecule is too small to be detected, I can still see the penny in my hand. Similarly, even though a single (double) strand of DNA is invisible, when they are all stuck together, one can see them with the naked eye.Tuckerekcut 16:49, 4 September 2006 (UTC)[reply]

i had tried the experiment at home with rubbing alchohol ,not ethanol (i dont have ethanol at homeas u have mentioned could this be the reason why i was not able to get the desired results. forgive me for my naivety because i 'm just a ninth grader.i appriciate your efforts at tring to answer my query.212.72.3.109 17:32, 4 September 2006 (UTC)[reply]

by the way what is an edit clash???212.72.3.109 17:34, 4 September 2006 (UTC)[reply]

For the record, it is not a prank. After developing it as a workshop for the The Edinburgh International Science Festival [28] I have personally extracted more DNA from more peas than one would think humanly possible. See here for a picture of the workshop [29] (though not of me!). Its pretty crude, its smells bad, and you often get protein contamination, but you do get floccules of DNA that you can fish out. Rockpocket 17:51, 4 September 2006 (UTC)[reply]

as i had mentioned before i'm justa naive ninth grader , could u be kind enough to enlightened me with the method u used 9 (not meant to be sarcastic in nature)and what is an edit clash ,(did 2 wikieditors clash sword s ???)212.72.8.224 18:08, 4 September 2006 (UTC)[reply]

An edit conflict is when two or more people try to edit a section or article at the same time. The second person to click 'Save page' has to do some sorting out to write what they want. Skittle 21:52, 4 September 2006 (UTC)[reply]

Also, I did almost the exact procedure described on that page in class. We used onions blended with washing up liquid, and it worked. Skittle 21:56, 4 September 2006 (UTC)[reply]

I remember passing someone at the Science Fair a few years ago who did a project like that. It worked for them, I guess. I've noticed, though, that almost none of those do-it-yourself science projects ever work for me, no matter how simple. In theory, I think I could create an antigravity system just by throwing something off a balcony. Black Carrot 06:06, 5 September 2006 (UTC)[reply]

i want to be adoctor

hi am 21 years girl ia am studying genteics engenering in jordan and my dream in this life to be adoctor in some day i wana ask if i can continue medicine after i finsh gentics and how many years i need and what i could do to know all the information that i need because i lessen that someone finish genetics and know he study medicine not from the first he continue i want to know if this true or not please help me because i need this help

am marwa abulel am have israelian nationality

I think this differs per country so your best option would be asking your student career counceler. They should be able to tell you exactly what's possible with your genetics degree and what you would need to become a doctor. - Dammit 16:23, 4 September 2006 (UTC)[reply]

You will be much better off if you can get out of Jordan for studying and practicing medicine. — [Mac Davis] (talk) (Desk|Help me improve)

How did you know that (practicing medicine in Jordan sucks)? ≈Eh-Steve 16:59, 4 September 2006 (UTC)

Where do you want to become a doctor? --Proficient 17:51, 4 September 2006 (UTC)[reply]

I guess you could do anything you want. I just figured you would be better off in Europe, Asia, or North America. — [Mac Davis] (talk) (Desk|Help me improve)

Psst, Jordan is in Asia ;-) - Dammit 22:48, 4 September 2006 (UTC)[reply]

If you are Jewish, you'd best get out of Jordan before you are murdered by terrorists. However, I'm assuming you're an Israeli Arab studying in Jordan, in which case you might be safe, except from random killings by terrorists. If you would like to work as a doctor in an English speaking country, you need to improve your English quite a bit. I suggest finishing your studies in an English speaking country, so you will pick up the language more quickly. I expect genetic engineers to mesh more closely with doctors in the coming years, with gene therapy becoming a major form of treatment in the future. So, your background in genetic engineering should be quite helpful. StuRat 03:44, 5 September 2006 (UTC)[reply]

To add to that, not only is it a good idea to have solid English skills if you want to work as a doctor in an English speaking country, but it is also an important (and extremely valuable) skill enabling you to communicate medical knowledge from the English speaking world (which is a good portion of it) into the world that speaks your native language. Even if you end up working as a doctor in Jordan, your English skills will be invaluable as you follow in the footsteps of reasearchers worldwide. Also, good luck! freshofftheufo ΓΛĿЌ 14:10, 5 September 2006 (UTC)[reply]

There is no need to get a medical degree in another country. Just on my floor of the hospital, there are doctors who got their degrees from: Nigeria, Syria, Israel, Greece, Norway, Canada, China, Tanzania (sp?), and the U.S. of course. Ones that recently left came from Panama, Australia, and Japan. Now, there is one advanatage to getting a degree in the U.S. - it can be basically free. The U.S. is very stupid about student loans. You can come to the U.S. and take out huge student loans to pay for medical school. Then, when you are done, leave the U.S. and never come back. If you don't come back, you never have to pay the loan back. The idea, as far as I can tell, is that the government thinks that if you spend a few years here you will want to stay (and pay taxes) for the rest of your life. --Kainaw ^(talk) 14:18, 5 September 2006 (UTC)[reply]

Death of Jupiter

The article on Jupiter points out that it expends more heat than it recieves from the Sun through the Kelvin-Helmholtz mechanism. My knowledge of thermodynamics isn't great but I do know that if it is losing more energy than it's gaining then it will eventually run out. What will happen to Jupiter and its sattelites as it cools down and "dies"? What impact will it have on the rest of the Solar System? Will the same thing happen to Saturn?

Regards, Gallaghp 16:49, 4 September 2006 (UTC)[reply]

Are the energy inputs from collisions with asteroids, and the moons gravitational pulls (atmospheric tides I guess you'd call them) enough to balance the system.

Also even if the planet was radiating more heat wouldn't the Kelvin-Helmholtz mechanism cause it to shrink until its surface area was small enough for it to be radiating no more energy than it is recieving, and balance the system that way. Instead of your proposal that the mechanism continues indefinately until the death of the planet. Philc _T^E_C^I 17:21, 4 September 2006 (UTC)[reply]

A good point. I was mainly concerned with Jupiter's influence over the surrounding planets and moons, such as with it's magnetosphere (am I right in thinking it's the biggest "thing" in the solar system?) which would certainly diminish along with the planet. I know it's composed of different elements but after sufficient shrinkage is it possible that it might behave more like the outer gas giants, Uranus and Neptune? Gallaghp 21:21, 4 September 2006 (UTC)[reply]

Hm, its magnetosphere is pretty colossal so I should imagine it wouldnt be shrinking to exclude its sattelites very soon, or ever, if the thing about it stabalising is correct. About it being the biggest thingin the solar system, it is (i'll spare you the perdanticities of the sun, and its related areas of effect). I might me getting out of my depth, as my knowledge of planet behaviours is not to good, but how does jupiter behave differently? Philc _T^E_C^I 20:18, 5 September 2006 (UTC)[reply]

Far planets have nothing to do with dying suns, they seem to be very cold already, I dunno if some more cooling may change their nor our way of life. -- DLL ^{.. T} 19:49, 4 September 2006 (UTC)[reply]

Um, i think you may have misunderstood the question, hes referring to the planet dying, not its sun. Philc _T^E_C^I 20:17, 4 September 2006 (UTC)[reply]

rubella virus

i know that the rubella virus lives in the respiratory tract, but does anyone know what happens to the respiratory tract whilst it is infected??

so if anyone knows anything, please tell!! luvSammie hero 19:39, 4 September 2006 (UTC)[reply]

While the virus resides in the respiratory tract, the patient is asymptomatic. This is called the incubation period. So apparently the virus has no direct ill effects on the respiratory tract. It is only when the virus enters the bloodstream that symptoms appear, none of which have to do with respiration, except perhaps for a runny nose. --Lambiam ^Talk 21:38, 4 September 2006 (UTC)[reply]

Editing problem?

I want to edit the section above on this page on complex carbohydrate, yet all I am given to edit is the Rubella virus question above. What's happening?

I get that a lot too, just refresh and try again, it usually works for me. Philc _T^E_C^I 20:33, 4 September 2006 (UTC)[reply]

Seconded. Anyone know what the underlying problem is? Does it just happen when you click an out-of-date "edit" link? Because I can recall times when refreshing wasn't enough. Melchoir 20:34, 4 September 2006 (UTC)[reply]

Could be an issue with transcluding, I can't exactly copy content at bot speed, so there is a bit of lag, but I've also been hitting a lot of server lag today, so that's probably more likely to be it--VectorPotential^{RD NEEDS A BOT (-:} 21:24, 4 September 2006 (UTC)[reply]

Usually what has happened is that – between the time you loaded the page and the time that you clicked edit – a section had been inserted or removed above the section you wanted to edit. Someone may have removed a duplicate section, added a new subsection, or a bot could have archived some of the older entries. Look at URL in your browser's address bar after you click one of the section edit links; the last part of it will be section=21 or something similar. Sections are numbered consecutively down the page; if one is added or removed, you'll end up editing the wrong section. Refreshing/reloading the page will usually fix the problem. TenOfAllTrades(talk) 21:41, 4 September 2006 (UTC)[reply]

Thanks, seems to work OK now.

How do the unintelligent think?

Although there has been over millenia a lot of effort put in to describe how the intelligent think, for example logic, nobody seems to care how the unintelligent reach their conclusions.

My question is prompted by what I observed recently on a long bus journey. I overheard a middle-aged woman talking to what I expect was her grandchild. She had been smoking heavily before boarding the bus. I heard her say that the sweets her grandson had were full of "good things", for example sugar; that you needed to eat a little sugar (as if it was some kind of vitamin or essential nutrient), but that eating too much sugar makes you thirsty (perhaps some warped misunderstanding of diabetes). I wonder how she could have reached these conclusions? Credibility? Inattention? Sentiment? What?

Understanding how the less gifted think would help us more priveledged people improve our thinking, and also be of use for advertising and propaganda. 62.253.52.76 21:28, 4 September 2006 (UTC)[reply]

Ill-informed? CAn be confused with lack of intelligence.--Light current 21:33, 4 September 2006 (UTC)[reply]

Your base assumption that fallacious thinking has gone unstudied is simply wrong. I wonder how you might have reached that conclusion? Ignorance? Melchoir 21:35, 4 September 2006 (UTC)[reply]

While I agree that mistakes in intelligent thinking in the form of fallacy has been studied, I am doubtful that unintelligent thinking has been - can you provide some evidence or links please?

Prospect theory. --best, kevin [kzollman][talk] 22:23, 4 September 2006 (UTC)[reply]

Obviously ignorance is studied and well understood, how else do you explain TV commercials? Why do you think people get paid millions to come up with the definitive SuperBowl beer commercial?--VectorPotential^{RD NEEDS A BOT (-:} 21:40, 4 September 2006 (UTC)[reply]

Hang on... beer commercials can be hilarious! Surely they're also accurate depictions of reality? Melchoir 21:42, 4 September 2006 (UTC)[reply]

I think your belief that this woman was unintelligent, at best, did not follow logically from the available information, and at worst, was elitist and judgmental. Sugar, a source of calories, is indeed a good thing nutritionally when not taken in excess. She might have been speaking in a sense other than nutritionally, as well, with a meaning along the lines of "sweets are good for the soul." Sugar is hygroscopic, so too much definitely makes you thirsty. In fact, for rehydration, highly sugared beverages such as soda are not favored. You should really examine your assumptions before reaching such radical conclusions about other people's intelligence. --Ginkgo100 ^{talk · e@} 21:47, 4 September 2006 (UTC)[reply]

While a packet of sugar sitting on the table may be hydroscopic, when sugar is digested I believe it releases water. (Sidenote - never try to drink blood when you're dying of thirst in a desert - the protein in it uses up more water in its digestion).

A classic example of Ignoratio elenchi or maybe Ad hominem.

Maybe she was lieing to the kid so that he wouldnt eat all of his sweets at once. Philc _T^E_C^I 00:36, 5 September 2006 (UTC)[reply]

I have a very closely related question. How do some presume, without any empirical evidence whatsoever, that they are more intelligent than others? What is the precise neurological malfunction causing this phenomenon? More specifically, what is the precise mechanism that serves to block their limited minds from considering that they may actually not know as much as they believe to know? In fact Socrates, one of the greatest thinkers humanity has ever produced, would clearly have no choice but to regard these individuals as the lowest of morons, for they, of all people, are the least bit in touch with their own ignorance. In the words of Socrates, true wisdom is only attained when one recognizes that one knows absolutely nothing. Loomis 02:31, 5 September 2006 (UTC)[reply]

I have also wondered why the less intelligent are also less concientious. According to scientists the answer is that both concientiousness and the executive functions of intelligence are controlled by the frontal lobes of the brain, so the two go together.

Is wisdom the same as intellignece? I would say not--Light current 02:44, 5 September 2006 (UTC)[reply]

Inductive reasoning is one type of "illogical" thought process which has been studied extensively. Also, if you look under fallacy and logical fallacy, you will see there are a many examples of logic errors which have also been studied thoroughly. StuRat 03:25, 5 September 2006 (UTC)[reply]

What does smoking have to do with sugar or intelligence? Black Carrot 05:44, 5 September 2006 (UTC)[reply]

THe implication seems to be that because the woman was smoking 'heavily' (although Im not sure how that could have been deduced since the questioner was on the bus, and the woman at the bus stop) It therefore meant she had a low intelligence.Maybe shes not wise to smoke-- but thats not low intelligence (I believe Uncle Albert smoked a pipe)--Light current 05:48, 5 September 2006 (UTC)[reply]

You've somehow decided that I was on the bus - I wonder how you reached that conclusion? In fact we were both queueing for the bus for a long time. I was trying to stay upwind of her to avoid her smoke plume.

I decided because of this sentence: what I observed recently on a long bus journey. You dont take bus journeys standing in a queue and you didnt day you were queing. So I assumed reasonably you were on the bus.

--Light current 08:51, 5 September 2006 (UTC)[reply]

I think the process the unintelligent use to reach their conclusions is different from the cold rationality of the intelligent. I think people form their ideas from sentiment and ego protection. For example, if a fellow student is much wealthier than onself, then you would tend to think he is an unpleasent person. I've noticed that the less intelligent spend nearly all of their time socialising with each other and hence have no time left to do any work - this may be due to a functional necessity to stop such petty jealousies arrising and thus leading to bullying. Most of them also definately think that matters relating to dominance in the here and now are far more important than anything else in the world.

Could there be such a thing as a logic of the unintelligent? This would require consistency. If you put a bunch of unintelligent people together, will they come up with a way of communicating that is devoid of logic as we know it but has a consistency of its own? Take insects, for example. They are way off the scale (at the bottom end) when it comes to human inteligence tests, yet they have functioning societies. Do they therefore have a logic of their own (that we humans don't understand)? DirkvdM 08:58, 5 September 2006 (UTC)[reply]

I think there's a lot of sense in that - ie the unintelligent believe in a 'set of truths' that are unrelated - ie no calculus is permitted on the different objects, so contradictions may exist and obvious conclusions are not drawn. Quite a pleasing logic from a mathematical POV however. Rentwa 09:56, 5 September 2006 (UTC)[reply]

What do you mean by unintelligent? I'm quite interested in abnormal psychology when it's actually morbid (especially autism), but if you're talking about average human moronicness it's just a hotch-potch of ignorance, poor culture, political degradation, drudgery etc. In Saturday's London Times there was an interview with a man who became prominent in homeless activism. He said (which I thought perceptive if a little damning) 'My family wasn't just poor, they thought poor and lived poor.' I remember a man in a pub telling me that 'if it was printed in the papers it had to be true', and no rational explanation of why this was false could shake his quaint view that there was a law (probably something to do with Magna Carta or Habeus Corpus) that journalists were honour bound to check every fact before commiting it to print. Or maybe he thought there was something special about the newsprint that made untruths vanish from the page, or maybe he had simply never thought about it for himself. I have a thousand similar jolly tales of working class life oop north, maybe I should write a book? Rentwa 09:08, 5 September 2006 (UTC)[reply]

It would seem that conclusions are reached based on emotion rather than logic. There is a theory - cannot remember the exact terms - but it was something like Festinger's congruency theory.

Self-expectation is very important in determining one's success or otherwise in life, perhaps more important than qualifications. That would explain why the children of the rich get rich themselves.

Is this why I'm editing wikipedia and not working on my book? :) Rentwa 10:00, 5 September 2006 (UTC)[reply]

You too, huh. We should form a "Society of Putative Writers Who've Become Temporarily* Diverted by Wikipedia". (*like, for years at a time). JackofOz 12:08, 5 September 2006 (UTC)[reply]

Apples and Saliva

I've noticed that my saliva becomes unusally viscous after eating an apple. This only happens with apples and not other fruits that I eat. What causes this? --Burbster 22:43, 4 September 2006 (UTC)[reply]

Anything with a lot of sugar causes an increase in salavia viscosity for me. Maybe that is it. As for the mechanism, I don't know. — [Mac Davis] (talk) (Desk|Help me improve)

I don't know the cause, but when i was a student i used to work in a lab that did genetic testing for cystic fibrosis. We used to get buccal swabs from which i would extract DNA. We found that, when the patient had recently eaten an apple (specifically), we would really struggle to get good quality DNA from the swab. I always assumed it was related to the acidity of the apple. I wonder if these two phenomena are related. Rockpocket 06:12, 5 September 2006 (UTC)[reply]

How natural cherry flavor is made

I would like to know how natural cherry flavor is made. Signed: "Nacherl"

steam distillation? Xcomradex 23:07, 4 September 2006 (UTC)[reply]

If it's natural, my best guess is that it's made from cherries. What am I missing here? Loomis 02:07, 5 September 2006 (UTC)[reply]

I think Nacherl is asking how they get the natural cherry flavor into the product. My guess would be they mash the cherries into juice, then add the juice to the mixture, be it candy, soda, or medicine. Hyenaste ^(tell) 02:10, 5 September 2006 (UTC)[reply]

no, i would say they distill the flavour molecules away from the pulp, to stop other components of the pulp interfering at a later stage. So i'd say distilled from cherries (or some other plant). Xcomradex 03:12, 5 September 2006 (UTC)[reply]

If you don't know the answer, then please do not substitute any random guess as a reply. --Lambiam ^Talk 08:14, 5 September 2006 (UTC)[reply]

I'm not sure how you meant natural, so I may be missing the point if the question but esters are used to flavour most things. Cherry flavour can be made from ethyl heptanoate, geranyl butyrate, methyl benzyl acetate and terpenyl butyrate according to the article. Philc _T^E_C^I 10:51, 5 September 2006 (UTC)[reply]

"Natural flavor" does not mean it actually comes from cherries. It means that it is the same chemicals as are in "artificial flavors" but has been synthesized in a "natural" way (there is a specific legal definition of this; see Flavor#Flavorants). They probably have nothing to do with actual cherries. "Natural" flavors are preferred by food companies because they sell better; they have otherwise no differences from "artificial" flavors. --Fastfission 14:54, 5 September 2006 (UTC)[reply]

If I'm reading that definition right (it is somewhat ambiguous), it does say that natural cherry flavorant needs to be made from cherries, or at least from some "spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, [etc.]". In particular, it says a natural flavorant needs to be an "essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating or enzymolysis", which rather restricts the preparation methods allowed. —Ilmari Karonen (talk) 20:43, 5 September 2006 (UTC)[reply]

How does human body maintain ph?

I assume that if our bodies did not maintain a constant ph, our metabolisms would go awry.

How does it do this? If you eat acid foods, does your urine become more accidic?

Is the average long term ph of the food you eat the same as your body ph? If not, why not?

Could you kill yourself by just eating acid foods all the time?

Thanks.

There are several buffer systems, of which the most important is bicarbonate, and several compensatory mechanisms (metabolic and respiratory). For further explanation you can consult a medical text on acid/base balance, or our articles on acidosis, alkalosis, metabolic acidosis, respiratory acidosis, metabolic alkalosis, respiratory alkalosis. We may have a more centralized discussion somewhere in Wikipedia? - Nunh-huh 00:01, 5 September 2006 (UTC)[reply]

negative feedback, through homeostasis, by use of blood hormones. Philc _T^E_C^I 00:34, 5 September 2006 (UTC)[reply]

Which hormone did you have in mind? Hormones have next to nothing to do with regulating acid base balance. - Nunh-huh 01:19, 5 September 2006 (UTC)[reply]

Vasopressin would affect blood ion concentrations and aldosterone is important to regulate sodium and potassium balance in the blood. -- Scientizzle 03:58, 5 September 2006 (UTC)[reply]

Yes, and the question was about pH! - Nunh-huh 04:24, 5 September 2006 (UTC)[reply]

Sorry, I should have been more clear. Hormonal alteration of ion balances is acheived by modulating ion & water transport activity in the kidney nephrons. Aldosterone stimulates H⁺ secretion, thereby raising the pH. Vasopressin will concentrate the urine, therefore also making the blood more dilute, too, and potentially reducing acidosis or alkalosis. -- Scientizzle 05:32, 5 September 2006 (UTC)[reply]

But neither of those effects are primarily mechanisms for regulating pH - they are epiphenomena. The primary mechanisms for regulating pH are those which I named in my answer. The questioner should not think that "blood hormones" are particularly important in regulating acid/base balance, because they're not. - Nunh-huh 06:14, 5 September 2006 (UTC)[reply]

farking edit conflicts: i remember a story about one of the early (german?) researchers (i forget the name) into blood pH eating 1 kg quantities of ammonium chloride and studying the effect, for those of you unfamilar with ammonium chloride, it is an acid with a "biting taste" (apparently) and an unpleasant ammonia smell. so i guess you can eat quite a bit of acid before fatally pushing the buffer equilibrium too far. Xcomradex 00:40, 5 September 2006 (UTC)[reply]

Ammonium chloride (also known as salmiak) is a salt, and not particularly acidic, though the evaporation of ammonia may make its solutions slightly so. Mind you, if you eat a lot of a highly acidic or alkaline substance, the immediate effect (assuming it's not acidic or alkaline enough to irritate or even corrode tissue directly) will be to change the pH of your stomach content, leading to indigestion. —Ilmari Karonen (talk) 05:33, 5 September 2006 (UTC)[reply]

Ammonium chloride is indeed a salt, but it is classically used for acidification of the urine. It has been used, for example, to test for distal renal tubular acidosis. - Nunh-huh 06:14, 5 September 2006 (UTC)[reply]

September 5

Discovering an alien probe

Let's say an alien robotic probe parachutes down to a suburban area in the U.S. Someone discovers it. What will happen next? Also, ideally, what should happen next? --Bowlhover 01:09, 5 September 2006 (UTC)[reply]

Our government would take it away. And convince that entire suburban area that the said event never took place. Russian F 01:39, 5 September 2006 (UTC)[reply]

George Bush would invade a country that wasn't involved. Peter Grey 02:10, 5 September 2006 (UTC)[reply]

Seriously, although I'm not very happy with the U.S. government, I don't think they're hiding anything about alien probes. They are hiding information about U.F.O.s, but those U.F.O.s are probably either natural phenomena or machines built by humans. --Bowlhover 03:35, 5 September 2006 (UTC)[reply]

The reason you don't think the government is hiding information about alien probes is that you do not believe there have been any alien probes. Now, if I were to tell you there have been several, and you believe me, would you still think the government isn't hiding the information? --Lambiam ^Talk 08:12, 5 September 2006 (UTC)[reply]

Why specifically the US? Is this meant as a question about US politics (as Peter took it to be)?

Given Peter's example, the person who discovers it should idealy inform international organisations first, before the US government finds out. The UN would be a good choice, but they would not have a mandate to claim it. No extra-USian governmental organisation would. So may be he should infomr a private enterprise and get them to transport it to a neutral country. But I don't know which enterprise would be willing or able and what constitutes a neutral country anyway. New Zealand? DirkvdM 09:08, 5 September 2006 (UTC)[reply]

Tell anyone except your own government first - that way there's less chance that they'd just spirit the thing away, never to be seen again. The UN, international news agencies, the Pope, anyone with a bit of clout. --Kurt Shaped Box 23:53, 5 September 2006 (UTC)[reply]

Am I the only one who doesn't think the authorities would cover it up? At least not after they confirmed for themselves what it was. freshofftheufo ΓΛĿЌ 13:49, 5 September 2006 (UTC)[reply]

Bill Clinton seemed absolutely thrilled to think that discovery of alien life had been done under his term (ALH84001). I think that the assumption that American politicians would be happier hushing something like that up does not take into account the political benefits of being the first president to announce contact with another civilization. --Fastfission 14:49, 5 September 2006 (UTC)[reply]

In a sense, the probe would have the initiative. If it can communicate, and has a sufficiently advanced artificial intelligence, then we'd be very interested in what it had to say; if it was damaged, then all we could do would be to analyze it. If it said it would only talk to the UN, we probably wouldn't argue. There would be a conflict between quarantining it (it could have extraterrestrial bacteria, or it could have become radioactive, etc.) and displaying to the media, given that there would be a natural skepticism about the discovery, especially if it had not previously be detected moving through our solar system. If it appeared in US territory, given that the US has the resources to examine it, they would probably handle it through military channels (because there could be a legitimate worry that it would be dangerous). A cover-up would probably be impossible. Peter Grey 17:59, 5 September 2006 (UTC)[reply]

separation of chemical compounds

How could you separate barium sulfate from ammonium chloride?

How could you separate barium chloride from calcium sulfate?

How could you separate tellurium dioxide from silicon dioxide?

Undesguised homework again? Choose some of the properties and use the most appropriate ones to aid separation.--Light current 02:00, 5 September 2006 (UTC)[reply]

i'm guessing reading isn't his/her strong point... Xcomradex 03:03, 5 September 2006 (UTC)[reply]

Mine neither--Light current 05:30, 5 September 2006 (UTC)[reply]

no for you it's spelling, unless it's all a clever desguise... ;-) (no harm intended). Xcomradex 08:07, 5 September 2006 (UTC)[reply]

I prefer to call it finger trouble! THe keys are too close on my keyboard 8-)--Light current 08:24, 5 September 2006 (UTC)[reply]

Salts like the ones you describe are usually separated using precipitation reactions. You need to figure out the rest. - Mgm|^(talk) 10:53, 5 September 2006 (UTC)[reply]

Sulfates of the Alkaline Earth elements are generally insoluble in water. Chlorides are usually very soluble in water. I do not have a clue about the last one, both are very insoluble in water, but maybe a solvent exists which is good for one but not the other.

For the third pair, one of them is twice as dense as than the other. See Silicon dioxide and Tellurium dioxide. Of course, I'd use a mortar and pestle and my firing oven, but that's just me... -- Fuzzyeric 00:06, 6 September 2006 (UTC)[reply]

California Moss Genus/Species

Can someone tell me the taxonomical binomial nomenclature of that common, general greenish moss that is found all over rocks and such on the southern West Coast? Thanks so much, ChowderInopa 01:58, 5 September 2006 (UTC)[reply]

You mean what its called?--Light current 02:04, 5 September 2006 (UTC)[reply]

Yes, I mean the scientific name. ChowderInopa 02:38, 5 September 2006 (UTC)[reply]

Can you say something more about its appearance? Are these damp habitats? Are you sure it is not lichen? --Lambiam ^Talk 07:59, 5 September 2006 (UTC)[reply]

~~The southern west coast of what?~~ Oops, missed the header. DirkvdM 09:09, 5 September 2006 (UTC)[reply]

satellite imagery maps

I need to know where to look for the satellite imagery maps. I want to see what my home looks like from above and the locations around my home. Please show me how to get there on wikipedia. Floyd — Preceding unsigned comment added by 68.119.96.36 (talk)

I'm too tired to do the whole 'build a satellite' launcher routine, fun as it would be. Google is your friend. Go there, and punch in your ZIP/postcode. If necessary, switch from map to satellite view. --Mnem e son 02:21, 5 September 2006 (UTC)[reply]

for even more google, try Google Earth. its great. Xcomradex 03:05, 5 September 2006 (UTC)[reply]

Do you smell burning toast?

Hey, could anyone settle a debate for me? My friend doesn't believe that smelling burnt toast, when there is no environmental source of the smell, could be a sign of a stroke. Is it a common occurrence, something that happens rarely, or just a myth? Thanks in advance for your input. --Dimblethum 02:52, 5 September 2006 (UTC)[reply]

It could be a sign that you suffered a stroke, and then tried to toast the same slice of bread 10 times, after which it would smell rather burnt. :-) StuRat 03:02, 5 September 2006 (UTC)[reply]

It may be a symptom of a stroke. (See for example this case study.) It may also be indicative of a brain tumour (it is sometimes a sign of brain metastases in advanced cancer), or of some neurological problem, or it could just be a passing random olfactory hallucination. An odour of 'strawberries' is also reported by some individuals. Some people have also reported a burnt toast smell immediately before a seizure or migraine. TenOfAllTrades(talk) 03:04, 5 September 2006 (UTC)[reply]

Burning rubber is another one. George Gershwin had this symptom before they diagnosed his brain tumour. Any disturbance to the proper functioning of the brain can produce visual, auditory, olfactory, gustatory, or kinesthetic perceptions of external phenomena that do not objectively exist. JackofOz 07:13, 5 September 2006 (UTC)[reply]

So are synesthetics in constant threat of a stroke? DirkvdM 09:19, 5 September 2006 (UTC)[reply]

I think you can work that one out yourself, Dirk. JackofOz 12:04, 5 September 2006 (UTC)[reply]

burnt toast

I've heard that burnt toast has the same calories as regular toast. I believe it has less, but negligably less compared to our caloric intake.

what are th e facts?

Jasbutal 03:52, 5 September 2006 (UTC)[reply]

That sounds reasonable, but I have no facts. I would guess that if a piece of burnt toast is still palatable enough to swallow, then it can't be too badly burnt after all, and its interior is still perfectly nutritious. Melchoir 03:58, 5 September 2006 (UTC)[reply]

I dont see how it can have the same, since some of the bread has been reduced to pure carbon. THat is how you tell the calorific value of food- you burn it in pure oxygen till theres only ash Food_energy#Measuring_food_energy.--Light current 05:09, 5 September 2006 (UTC)[reply]

I'd say both statements are probably correct; there isn't necessarily any contradiction between "(approximately) same" and "negligibly less". (Or course, that depends on how burned the toast is — if you burn it all the way down to water, carbon dioxide and ash, it won't have any caloric value left.) —Ilmari Karonen (talk) 05:23, 5 September 2006 (UTC)[reply]

Exactly. So how many calories would you like in your toast this morning Sir?--Light current 05:27, 5 September 2006 (UTC)[reply]

As dry as it may seem, regular toast still contains a considerable amount of water. The overheating that causes the toast to burn also evaporates some of the water. The net effect on the calories per unit weight may initially be an increase. --Lambiam ^Talk 07:51, 5 September 2006 (UTC)[reply]

Yes that is why toast racks are used I believe- to let the toast dry out and not go all soggy.--Light current 08:10, 5 September 2006 (UTC)[reply]

Blindness and circadian rhythm

I recall reading about an experiment where some college students were locked in a windowless suite of rooms without a clock, and were invited to sleep whenever they wished. Many of them began sleeping at unusual times that wouldn't map well to the 24-hour day. However, when they were made aware of the sun's progress, their sleeping patterns began to approximate the day-night cycle. Is anyone else aware of this study? My question is this: do the sleeping habits of blind people tend to be independent of the sun? Presumably the only non-visual distinction between day and night would be one of temperature, and if the person remained inside in a climate-controlled environment, this would not matter. Long question short, is there any record of blind people having trouble casually (i.e. without having to put special effort into it) distinguishing night from day, and experiencing sleeping problems as a result? Is it plausible? I'm not talking about people with jobs and schedules, but people who might not pay close attention to clocks, such as people in hospitals or retirement homes. Bhumiya (said/done) 05:00, 5 September 2006 (UTC)[reply]

I don't believe your assumption that blind people are less aware of the time of day is correct. They have a variety of ways to check the time, from audio watches, to radio and TV broadcasts, to periodic events, like church bells ringing, etc. While it's true that a blind person in a coma in a hospital would be unaware of the passage of time, the same is also true of a sighted person in a coma. StuRat 07:12, 5 September 2006 (UTC)[reply]

Years ago I remember seeing a tv doc about people living in windowless rooms without any time cues. They started to live on a 25 hour cycle, which curiously enough is the same length of day as on MARS!!

I think blind people would take their cues from tv, radio, alarm clocks, and other people.

But I think the intresting question is whether you can force your body to physiologically adapt to an arbitrary night/day cycle without the usual help you get from light, which causes your brain to secrete a variety of transmitters that entrain your circadian rhythm. I guess it would depend on what the exact cause of the blindness is. Nrets 16:56, 5 September 2006 (UTC)[reply]

Mantle

Has there ever been an attempt at diging down through the crust to reach the mantle?

Yes I think it was called the Mohole project.--Light current 05:29, 5 September 2006 (UTC)[reply]

...which failed. The Japanese are going to have another go at this next year. See Chikyu Hakken.--Shantavira 06:06, 5 September 2006 (UTC)[reply]

At the risk of asking a silly question, wouldn't that cause magma to rise and cause a volcano? I suppose one would have to make sure to drill at the right spot, where the is no magma chamber. Did I just answer my own question? DirkvdM 09:32, 5 September 2006 (UTC)[reply]

If you'll forgive me for attempting to answer a question that I myself was about to ask: I believe any area that would be in danger of spurting would be doing so already, or at least would be showing some sort of bulge. Any low/thin area of sea bed should conceivably be on top of a relatively inactive section of magma. freshofftheufo ΓΛĿЌ 13:38, 5 September 2006 (UTC)[reply]

And yes, I guess you did ^_^ freshofftheufo ΓΛĿЌ 13:40, 5 September 2006 (UTC)[reply]

Awesome.

At the risk of accusation of adding rubbish comments, I would say I tend to agree with the bulging hypothesis--Light current 00:03, 6 September 2006 (UTC).[reply]

Is it Bad to run PC without proper Earth supply?

Hi friends!...I've been using pc for a couple of years without supplying earth because in our block we have no earth connection to ground...Now is it ok to proceed so or need to give earth?..however I can feel some earth(mild current shock) passing on me whenever I touch the metal parts in the PC because of no earth..I know why this is,because of the returning current has no path way to ground an hence circulating in the cabinet and in all the metal parts..Some say it will affect HDD or RAM soon...Is it so?..and is it okay to proceed as usual?...or should I take immediate action for earthing?.But until now I haven't gotten any faults in my PC...Please help friends...My advance thanks

I'd say if you are feeling any shock at all, then yes, the computer should be grounded, immediately. (It's also a good idea, in any case.) :-) StuRat 07:06, 5 September 2006 (UTC)[reply]

Do you mean you should be grounded? What naughty things have you been upto this time? DirkvdM 09:36, 5 September 2006 (UTC)[reply]

If you have an external AC adapter, you should not be in danger of a serious shock, as it only delivers a low voltage (say 16V) to your PC. With an internal power supply, you might get electrocuted, which is generally not recommended. You could use a voltage meter to check if any metal parts carry an unsafe voltage compared to ground. --Lambiam ^Talk 07:34, 5 September 2006 (UTC)[reply]

Thanks...I recieve some mild shock inside the PC only...Maximum voltage of the SMPS (Internal Power Supply output only) is 12V.So I guess there shouldn't be risk of high volage shock..but say the current rating is as high as 22A..The shock is mild only which is bearable though..My suspect is that if it's gonna affect my hardware parts?...I haven't recieved any complaints yet since from the time I bought I've been using without earthing...

Unless this equipment is double insulated (which I doubt, if it has a metal case), it is not only undesirable, it is downright dangerous and even LETHAL. THe fact you are getting shocks should tell you this. Switch off NOW, unplug from the socket, and contact a reliable electricain immediately!--Light current 08:05, 5 September 2006 (UTC)[reply]

Isn't that last advise a bit over the top? I've connected my computer case to an unpainted part of a radiator. Shouldn't that suffice? DirkvdM 09:36, 5 September 2006 (UTC)[reply]

No I dont think so. The BS regualtions state that Any Class 1 equpt should have all exposed conductive materials solidly earthed to the mains earth. Furthermore, there is a requirment that the loop resitance of live and earth shall be less than a certain amount so that the protective device is activated. --Light current 13:22, 5 September 2006 (UTC)[reply]

The equipment is double insulated (wire casing and psu casing) until it gets to the PSU and after that the voltage and current are whacked down from hairburning to finger tickling levels. so... people should be alright. Philc _T^E_C^I 10:44, 5 September 2006 (UTC)[reply]

In the UK I'm sure it would be illegal to have an electricity supply without an earth. But in America......

Still though, most household items dont have an earth, only ones with metal casing do, often they dont even have an earth pin, just a dud plastic one. Philc _T^E_C^I 10:44, 5 September 2006 (UTC)[reply]

I thing no one here has grasped exactly what I meant.I told you that the shock is not severe at all and it's just a leakage current due to the absence of proper earthing....The shock is bearable only...This shock wasn't observed when I checked it with my friend's house(He has earth in his house)since the PC operates with only 12V,how can it be so lethal and dangerous?..The cause why I recieve shock should be b'coz of leakage current circulating over the panels....It's seems no threat to humans though I suspect if it can be for the Hardware in my PC...If I touch the RAM,HDD it gives me this mild shock still...I really wonder when it will die hard...

This is stray voltage, as in this ref [30] It is very bad for cows. For people, it is not that good, especially if one day you are touching the case, and the water tap at the same time. You could put on a Residual-current device, or attempt to ground with a pipe. Most likely, there is a short in the computer that will limit its life. --Zeizmic 12:28, 5 September 2006 (UTC)[reply]

If youre feeling anything, it means that electric current is flowing from your computer metalwork through your bod and down to earth. THis means that the casing is live and dangerous. I advise you get it looked at! It really sounds as if this eqpt needsan earth. Check the handbook!

THe danger comes from the fact that mains voltages are entering the power supply. If the power supply is faulty, the case can become live. If the case is not earthed, protective devices (fuses, breakers) will not operate and you are in danger of ELECTROCUTION! Please take it from me. I have experience in this field.--Light current 13:31, 5 September 2006 (UTC)[reply]

The usual phenomenon with lots of big SMPSs is that there's a big RFI filter right at the mains power input; the filter blocks both RFI coming into the supply from the line and power supply hash going back out onto the power line. This filter usually takes the form of an LC "pi" filter on both the neutral (return) and hot (live) lines, usually with pretty substantial capacitors to the safety ground which, of course, is then connected to the chassis of the SMPS and whatever the SMPS itself is then bolted to. If the safety ground lead isn't so hot or is outright disconnected, you find that the capacitors make a voltage divider that puts the chassis at about 50% of the line (mains) voltage, and most people can definitely feel that ;-). Whether or not it's enough current to cause a hazard depends on the design of the specific power supply, but I think that regulatory agencies won't permit such large capacitors in the pi filters as to allow a dangerous amount of leakage for ordinary equippment that is expected to be used in a residential or office environment.

At Digital Equipment Corporation (my former employer), because our high-current pi filters had larger capacitors, we had to put warning labels on the power cords of our big commercial equipment warning folks that there was enough leakage capacitance that the safety ground had to be connected to earth; otherwise, unsafe amounts of AC leakage current would occur.

So that's one aspect of the problem: ordinary operation. Then there's the question of the various faults that can occur. I'm in complete agreement with the folks above that because certain faults could possibly lead to mains power being connected to the chassis, it's essential that things that have a safety ground pin on their line cord (mains flex) either be connected to an actual safety ground or be connected to the mains through a residual-current device (ground fault circuit interrupter/GFCI). Those two methods are the only way to assure your safety if a worst-case fault occurs in the power supply.

And then, of course, there's the question of electrostatic discharge and your computer's ability to resist that. Absent an intended safety ground, you may find that your computer isn't able to resist static discharge (for example, sparks from you) to the degree that you would have expected. But that only endangers your data, not you.

Atlant 00:03, 6 September 2006 (UTC)[reply]

Memory and aging

Can you please find me information about Barnes' 1997 experiment with rats. he tested how the rat's age affected memory.

thank you.

Google is your friend. Just search for your key terms such as: Barnes 1997 experiment rats memory. Dismas|^(talk) 07:44, 5 September 2006 (UTC)[reply]

you won't have luck with rats around here, there are no experts. but if you were to ask about barnes's earlier experiments with seagulls... Xcomradex 08:11, 5 September 2006 (UTC)[reply]

ARRRGH--Light current 08:26, 5 September 2006 (UTC)[reply]

No expert on rats ? That's not fair ! StuRat 23:16, 5 September 2006 (UTC)[reply]

Phloretin, phloridzin

According to the literature, both of these chemicals seem to inhibit glucose transport into cells. -idzin has a glucose molecule attached, where -etin is exactly the same molecule, just missing this glucose moiety. Does anyone have any insight into why this is, as it's quite counter-intuitive. I would expect -idzin to be an "invincible substrate" kind of thing, but then how does -etin work?

Thank you very much Aaadddaaammm 09:04, 5 September 2006 (UTC)[reply]

i guess it shows you the aglycone of phloretin is active piece, not the glucose bit. phloretin is a protein kinase C inhibitor, as well as an inhibitor of a number of transporters, including the glucose transporters. so that's where the effect comes form, it's just coincidence phloridzin has glucose on it. [31]. Xcomradex 10:18, 5 September 2006 (UTC)[reply]

How processors work ?

How the control unit of a CPU/PROCESSOR/MICROPROCESSOR works ? I've cearch in wikipedia and in other sites but they all provide me the information that microprocessors are made of transistors ; several electronic gates like and,or,not are described . But i want to know the process by which microprocessors control an electronic device using 0&1 as input . How transistors are placed in a microprocessor ? How the increasing number of transistor in a processor increase the processing speed of a microprocessor ? What's the minimum number of transistor that can form a microprocessor (it will be better if a circuit is drawn showing positions of transistors and explanation of where the circuit takes input and where the output)? Explain the working procedure of microprocessor by an example of mp3 player .

Does the above question sound like a homework assignment? Explain your answer with reference to the above text :PPikiwedian 09:52, 5 September 2006 (UTC)[reply]

The information is all in Wikipedia. I doubt whether anyone is going to give you a succinct answer to all your questions here as they involve several different disciplines. Have you looked at transistor, digital circuit, logic gate, and microprocessor? --Shantavira 10:28, 5 September 2006 (UTC)[reply]

Yes,though most of us know it better,we can't keep typing everything in here.It's practically impossible..My suggestion is to have a good book knowledge first....But we can give some basics what we can....First you must know the internal architechure of any basics Microporcessor atleast like 8085,8086 (x86 series basics is good).Try google search for the architechure 1st.It's quite easy to learn...Your question is multi-directional and it confuses me where to begin with...I'll drop some basics that should be useful...later check the Wikipedia or in google, in detail for learning about transistors in digital circuit and logic circuits that control devices as Shantavira said. 1)Any control unit uses multiplexers(MUX) and DMUX to send signals to the multiple periperals with reduced pins in IC.This helps in reducing the CPU size...These are usually done with the aid of gate combinations eg.,NAND or XOR etc....So to enable a peripheral,all it needs to send is a low or high signal like(READ or WRITE or READY or ACKN or etc)which is an information that can be obtained from reading the instruction stored in RAM with respect to the CPU clock.It has Address Bus and Data Bus inside...Upon executing each instruction step by step,your CPU(Program Counter\Stepper)places the next intruction address and starts fetchin the data from RAM.This process keeps on cycling according to your program....Upon this,instruction is something which has information about the operation type and the Data for that operation written in Machine Language.This is depicted as opcode(operation type) and operand(operation Data) which is a standard format of any instruction. For eg.,

      "INSTRUCTION = (OPCODE+OPERAND)"
                   =    "OUT FFh".

Here Out is the OPCODE and FFh is the peripheral address.The data to be sent to this device is stored in one of the data registers.Each instruction is stored in different address in your RAM.So All you gotta do is to write your desire instructions and then store it in RAM and begin executing..There you go.....Here The opcode tells the CPU to send the data in it's default register to the device which is in the address 0xff location....Upon executing this instruction,the CPU 1st reads the Opcode only in it's first clock cycle and then it understands the meaning of that operation and it generates control signal accordingly and clears the pathway to this address and sends the data by reading the Operand in its next clock cycle.By decoding opcode,CPU can determine it's action and it generates the control signal...Provided the CPU has many supporting registers(unit for storing data) for ALU operation....so it can store frequent data up there and refer to it..Note it's only the instruction of your program that makes the CPU to geneate control signals...Your electronic device when connceted to CPU,automatically it must be given as address so that it can be identified uniquely like IP address...as we looked the instructions,just choose the appropriate insturction for controlling the device....For more and detailed information about the generation of control signals,please check out your text books... 2)About the transistors,the ON and OFF state is the only means by which we can store any data digitally.perhaps if one transistor is required for just storing one bit(0 or 1),then 8 transistors are required for 8-bit and so on..Technically they no longer call it as 8 transistor,but simply as Register and they give names like reg A or reg EA or so on....So a 32 bit CPU like any pentium processors has registers of 32-bit lengh,but it can have 16 or 8 bit units still...More the amount of registers,more number of intructions can be executed and stored and hence maintaining parallelism....so more number of transistor,more powerful and faster your CPU is. 3)Since 4004 is the 1st microporcessor(to my knowledge) which just had about 2300 transistors with operating clock of 108 KhHz...It's only a 4-bit processor(Data bus only) compared to any 32/64 bit processor now...So I guess atleast 2300 number of transistors might be required for making a CPU with reduced size(I'm not though sure) 4)Similarly for playing music CD's there are always some default instructions which are stored in your player's memory permanant.They are nothing other than the one that tells your procesor about seeking the CD with spin up and spin down command and also how to control the laser movement in readind the CD directory..You can learn more about this by experimenting with Microprocessor controlled Stepper motor.Once locked to the track in the disc,it keeps the trace and starts moving horizontally hence giving the data(music) from the pits....Apart from this,all user interfaces(Buttons,LCD,etc) are all controlled by microporcessor(Microcontroller is used these days instead) only...Regarding MP3 or other formats of audio,comp/decomp and all kinda processing is done by DSPs only...Besides these there are lot to know....I hope this Basics should help somehow..(Correct me if I'm wrong)

You may also want to read [32] and subpages. (You probably need some knowledge of informatics or electric engineering to understand that.) – b_jonas 21:38, 5 September 2006 (UTC)[reply]

Smelling things that aren't there

Ever since high school I have had periods of time where I would occasionally smell what I can most closely call cigarette smoke (although not quite). The whole thing seems to be psychological and fairly random (I'm not sure of any specific triggers), I can go months at a time without smelling it. and I have a friend who has had a similar phenomenon since her uncle died of lung cancer. Strangely enough, another friend has the same situation but with "hospital smell." I don't like cigarette smell and the latter friend doesn't like the smell of hospitals. Is there a term for this? Am I going to die? AEuSoes1 10:03, 5 September 2006 (UTC)[reply]

Well, I doubt you're dying, but according to Wikipedia:Reference_desk/Science#Do you smell burning toast? it might be a symptom of a stroke. I don't know what smelling things without a source is called, but if you worry about dying, you should see your doctor about it. - Mgm|^(talk) 10:50, 5 September 2006 (UTC)[reply]

That's what made me think of this, but I'm not smelling it constantly, which the case study stated. According to the page on strokes I (a 24 year-old in fit health) am not really at risk for a stroke. AEuSoes1 11:23, 5 September 2006 (UTC)[reply]

Some more information and links can be found under hallucinations and olfaction. There's also an unreferenced stub article on phantosmia. If you're worried, please go see a doctor. We cannot give medical advice at the reference desk. ---Sluzzelin 12:19, 5 September 2006 (UTC)[reply]

Is it possible you're actually around people who are smoking? Maybe they're smoking something close to cigarette smoke.--152.163.100.74 12:33, 5 September 2006 (UTC)[reply]

Intermittent smells can also be a sign of an impending seizure or migraine. See aura. Not common, but certainly possible. InvictaHOG 20:40, 5 September 2006 (UTC)[reply]

The whole "am I going to die" part was actually a joke. I've already been to a doctor about this and he thought it might be an allergy to something (if it walks like a duck...). Thanks for the info. AEuSoes1 21:02, 5 September 2006 (UTC)[reply]

Plane speed

If a plane is flying east to west, does it travel faster relative to the ground because of the spin of the earth? Or does the fact that the air it is in also spins cancel that out? Richard Bladen 13:24, 5 September 2006 (UTC)[reply]

The latter. Consider that at the equator the rotational speed of the Earth is over 1000 miles per hour, faster than the cruising speed of virtually all aircraft. However, US->Europe flights are usually of shorter duration than Europe->US flights due to prevalent winds. — Lomn | Talk 14:44, 5 September 2006 (UTC)[reply]

And for planes that get into the jet stream, the difference in speed is even more dramatic. Planes routinely use both ground speed and air speed to measure their velocity. StuRat 23:10, 5 September 2006 (UTC)[reply]

Keep your bowels fit?

Will your bowels deteriorate if they don't get anything to "work" with, food for instance? I was just wondering, if a person's nutritious requirements were met simply by eating a capsule the size of a walnut once a day (very futuristic), leaving the bowels inactive for most of the day, would the bowels stop working/deteriorate in function? Jack Daw 13:37, 5 September 2006 (UTC)[reply]

Your body would still need to dispose of bile and dead blood cells - the stuff that makes your poop green or brown (depending on which is in excess). So, even without food, your bowels would continue pushing "stuff" through. I think the real "victim" would be the population of bacteria in your bowels waiting for something good to eat. --Kainaw ^(talk) 13:55, 5 September 2006 (UTC)[reply]

So what about the bacteria then? What would happened to them, and how would that affect us? Jack Daw 14:27, 5 September 2006 (UTC)[reply]

I'm actually not sure anybody knows the answer to this, since such a diet does not yet exist. Some information may be gleaned from victims of malnutrition, but the malnutrition itself confounds the observation. In other words, it may not be clear whether a particular intestinal symptom is due to lack of activity in the bowel or to lack of nutrition for the cells. --Ginkgo100 ^{talk · e@} 20:20, 5 September 2006 (UTC)[reply]

Actually, the bowel begins to decondition shortly after a person stops eating/drinking. This happens a lot in the ICU setting. As for bypassing the bowel entirely, we don't need pills. We actually routinely completely bypass the bowel by using total parenteral nutrition, which is basically food through the veins. There are people who have lived decades without eating. InvictaHOG 20:42, 5 September 2006 (UTC)[reply]

So, yes, the bowels will deteriorate without food, perhaps to the point where they become completely unusable, forcing the victim to live the rest of their life getting all their nutrition via an IV. Not a pleasant prospect. StuRat 23:05, 5 September 2006 (UTC)[reply]

How does retinol kill?

The retinol article says that retinol can kill you, but How? It doesn't say. Anyone's got an answer?

The liver eventually can't store any more retinoids and they enter the blood stream causing a strong and dangerous immunological response called sepsis. See also hypervitaminosis A.---Sluzzelin 14:20, 5 September 2006 (UTC)[reply]

I see. And why does increased serum retinol cause sepsis? Jack Daw 14:26, 5 September 2006 (UTC)[reply]

On a similar subject, said article also states that: "The livers of certain animals, especially those adapted to polar environments, often contain amounts of vitamin A that would be toxic to humans." Why do polar animals have greater hepatic concentrations of retinol? I suppose it helps them in some way, but how? Jack Daw 13:42, 5 September 2006 (UTC)[reply]

Due to the scarcity of vegetable food, arctic super-predators, such as polar bears, eat a lot of other animals who are also predators. Organic compounds tend to accumulate up the food pyramid. See biomagnification. Higher hepatic concentration of retinol doesn't help the animals directly, some of them have just adapted greater storage capacity for organic compounds, thus avoiding sepsis. ---Sluzzelin 14:20, 5 September 2006 (UTC)[reply]

Naturally. Thank you. DS

request for location of manuals and papers

Can somebody say me a good website to find detailed and illustrated manuals and papers on any of the following topics : neural network, artificial intelligence, power electronics, power quality, robotics, VLSI, HVDC transmission and electronic topics? thank you for your help.

Start by searching for the terms in Wikipedia, and reading the articles you find. Then read the references in the Wikipedia articles. Then Google the terms and read the websites you find. Then go to a public library and ask the reference librarian to help you find books and magazines on the topics of greatest interest. Edison 20:19, 5 September 2006 (UTC)[reply]

backlog?

Has it ever occured to anyone how much Backlog sounds like B'log? Blog? Backlog? What are the scientific chances that 2 unrelated words would sound so similar--152.163.100.74 14:15, 5 September 2006 (UTC)[reply]

This is a rather vague question. Anyway, the words are related -- quite closely. They're two compound words both using "log" plus a leading descriptor. As for sounding alike... I find that it's fairly hard to confuse a two-syllable word with a one-syllable word, particularly when the extra syllable is the stressed one. However, languages generally reuse bits of sound (check the Language desk for better explanations). For example, a word starting with "str" is scientifically unlikely if you just generate character strings, but it's easy to think of a great many English words satisfying the condition. — Lomn | Talk 14:56, 5 September 2006 (UTC)[reply]

They're called homophones. JackofOz 00:09, 6 September 2006 (UTC)[reply]

Gourami identification needed

I need help identifying which species is in this picture. I own the fish, but I never bothered to ask what species it is. The image is currently on Trichogaster trichopterus because it mentions "golden" varieties, but I'm not sure if that's right (the markings look different). Help would be greatly appreciated. --Pharaoh Hound (talk) 14:59, 5 September 2006 (UTC)[reply]

It is a golden variety of blue gourami (Trichogaster trichopterus) as you thought. --Ginkgo100 ^{talk · e@} 20:08, 5 September 2006 (UTC)[reply]

Simple Law of Motion Question

Simply stated, in a practical application, would a ball dropped in a moving train fall directly down, or would it experience some movement towards the back of the train (assuming the train is moving at a constant speed)?

From the pov of someone in the same carriage, the ball would appear to drop vertically to th e floor. From the point of view of someone watching from the trackside, the ball would appear to travel in a parabolic trajectory.--Light current 15:16, 5 September 2006 (UTC)[reply]

[Edit conflict] (Assuming the train and ball are already travelling at a constant velocity) To a person on the train, the ball falls straight down. To a person obseving from outside the train, the ball falls both down (accelerating at one g) at forward (at the velocity of the train). Raul654 15:17, 5 September 2006 (UTC)[reply]

Should your train for any reason at all be situated in space, the ball, once dropped, should move alongside you without much trouble at all. :) 81.93.102.45 16:55, 5 September 2006 (UTC)[reply]

It is accelaration that would cause the ball to fall in a curved path relative to the train, not velocity, assuming the carridge is a sealed capsule, (i.e. if your on a flat bed, the wind would blow it back). Philc _T^E_C^I 20:10, 5 September 2006 (UTC)[reply]

There's always a caveat, so just to ruin the party: if the traincar in question has a lot of open windows, the resulting draft would push the ball towards the back of the train. Melchoir 20:17, 5 September 2006 (UTC)[reply]

Also, the ball would only fall straight down if the train is moving at constant speed in a straight direction. StuRat 22:50, 5 September 2006 (UTC)[reply]

Strange insect identification

Hello, can anybody help me identify this strange insect I found in my garden? Thanks in advance. Davide125

Froghopper? It looks like the insects that come out of cuckoo spit in my garden, and cuckoo spit redirects to that page. Skittle 17:23, 5 September 2006 (UTC)[reply]

Froghoppers are rather small. How big is this critter? Also it might help to know which country your garden is in.--Shantavira 17:28, 5 September 2006 (UTC)[reply]

Me? England. I thought this beastie looked smallish too, given its size against the leaf. Happy to be corrected though. Skittle 17:30, 5 September 2006 (UTC)[reply]

Thank you for your reply. The insect is pretty small, about 3-3.5 cm including the antennas. The garden is in northern Italy. Davide125 18:21, 5 September 2006 (UTC)[reply]

Construction of Light Emiting Diodes (LEDs)

I am particularly working on a project whereby I need to construct a 2-Volts-DC LED lighting — 17:38, 5 September 2006 (UTC)17:38, 5 September 2006 (UTC)83.229.66.186

Construct from what starting point? Do you have a handful of LEDs and resistors from Radio Shack? Do you have a some PN junctions? Do you have some appropriately-doped pure semiconductors? An undoped Si crystal? A pail of beach sand? DMacks 19:03, 5 September 2006 (UTC)[reply]

Hehe, I have sometimes thought about how long it would take to, say, build a computer, if all you had to start with was the natural resources. One could imagine that mankind, because of a natural disaster or something, lost all of present technology. Mabye there is only some tenths or hundreds of people left. How many generations would it take to build a computer (or go to the moon, or build a submarine, …)? The first generation would have to try to pass on all their knowledge to the next (a great task in itself), but they hardly know everything, so future generations would have to, well, not reinvent the wheel, but a whole lot of other things. Or could it be accomplished while the starting generation is still alive? —Bromskloss 21:33, 5 September 2006 (UTC)[reply]

Given that you have the led and a 2 volt light source, the big trick is to connect the led so that it is biased to conduct elctricity, and to have a resistance in the circuit to limit the current to an appropriate amount. See LED circuits. Edison 20:24, 5 September 2006 (UTC)[reply]

what kind of mirror has best reflection of visible light ?

I want to know how much percent the best mirror for the visible light,reflects ? —The preceding unsigned comment was added by J.hesam (talk • contribs) .

Maybe spectralon. Its reflectance exceeds 99%.---Sluzzelin 19:07, 5 September 2006 (UTC)[reply]

The "Technology" section of the Mirrors page has some info. DMacks 19:08, 5 September 2006 (UTC)[reply]

Dielectric mirrors can reflect >99.999% of a narrow band of wavelengths. In 1998, MIT claimed they had created a so-called perfect mirror that was a "very efficient reflector over a broad range of angles". I haven't been able to find any exact numbers or more recent details about it, though, so it might not be much more than a research prototype. -- Plutortalk contribs 19:11, 5 September 2006 (UTC)[reply]

I found a few (potential) primary citations for that work...see Talk:Perfect mirror). DMacks 19:27, 5 September 2006 (UTC)[reply]

Sluzzelin: the spectralon article claims that it has a very high diffuse reflection, so it's definitely not a perfect mirror. – b_jonas 21:27, 5 September 2006 (UTC)[reply]

What would happen

if an unstoppable force collided with an immovable object (assuming it were possible)? A Clown in the Dark 18:22, 5 September 2006 (UTC)[reply]

Irresistible force paradox ---Sluzzelin 18:51, 5 September 2006 (UTC)[reply]

Ah, that was simple. Thanks! A Clown in the Dark 18:52, 5 September 2006 (UTC)[reply]

I think this is Lambiam's principle of explosion. :) Rentwa 21:11, 5 September 2006 (UTC)[reply]

genetically modified foods

what is the mean of genetically modified foods?

Basically it is transformation with new DNA, often from an unrelated organism. David D. (Talk) 21:11, 5 September 2006 (UTC)[reply]

Perhaps typing "genetically modified foods" into the Search box would have been a good place to start learning on your own... DMacks 21:13, 5 September 2006 (UTC)[reply]

What is the process of liqiudizing Oxygen?

I just want to ask a question about liquidizing Oxygen. Thank you. --64.180.82.114 21:40, 5 September 2006 (UTC)[reply]

According to Liquid oxygen, the usual process is fractional distillation. I guess you just condense ordinary air first. Melchoir 21:42, 5 September 2006 (UTC)[reply]

You would also need to lower the temp quite a bit, wouldn't you ? StuRat 22:51, 5 September 2006 (UTC)[reply]

Liquid air talks about how to condense ordinary air, including separation of different components by their boiling point. DMacks 23:01, 5 September 2006 (UTC)[reply]

Ah, there's the money link. I've put it into the See also. Melchoir 23:20, 5 September 2006 (UTC)[reply]

Reference voltage for decibel measurement

When calculating frequency repsonse on electronic hifi equipment, what is the reference voltage for the decibel measuremnet used in a frequency vs dB graph? Is it the ' perfect ' output voltage?

I think its 0 dBm ie 775 mV rms.--Light current 23:58, 5 September 2006 (UTC)[reply]

canine dental

I have a five month old Standard Poodle, that has adult teeth coming in missing enamel on 1/3 to 1/2 of each tooth. I am researching the probability of heredity/genetic traits to notify the breeder of possible health related concerns. All her teeth will have to be capped to prevent decay. I have read many articles suggesting auto-immune issues; and want more information on related documented cases and results. I can send pictures. Thank you. [email protected]