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July 24

Vindon, anthracite-based synthetic fibre

In reading a passage on North Korean history (written by an Englishman), I came across the following line: [North Korea] even managed to clothe its own population by inventing an anthracite-based synthetic fibre called vindon. [1]

Does this go by another name? I'm having trouble finding information on "vindon". --0g 06:11, 24 July 2006 (UTC)

Vinalon --Seejyb 19:32, 24 July 2006 (UTC)

Thank you --0g 23:37, 24 July 2006 (UTC)

Speed of time?Reality is instantaneous?

Imagine there is a string and a laser beam at one end, the other end of the string and a light detector seperated by one astronomical unit(mean sun earth distance).Suppose I were to pull the string and switch on the light at the same time, what would be observed at the other end? Is it that the light and string dislacement would be observed at the same time? or the string displacement would be noticed much much before?(guess light would take 7minutes to reach).

The light would arrive first, while the string-jerk would be delayed by many years. When you yank on a string, the yank is exactly the same as a sound wave. It's a sound wave inside a solid (a compression wave or "P-wave".) The "yank" will travel along the string at the speed of sound in taut string. What's that speed? The speed of sound in solids is typically far faster than in air, and the speed of sound in air is around 720 MPH. The "yank" in the string would travel at at least a few thousand MPH.

Whenever we pull or push upon any object, the entire object never moves as one. Instead, your hand pushes on one part, and that part moves slightly forward and pushes on the neighboring parts, which then move forward and push upon the next neighbors. The "push" and the forward motion is travelling as a wave. Since this wave usually travels at hundreds of MPH, to human eyes it looks as if the solid object moves as one. We don't notice the wave that zips rapidly from one end of the object to the other. The wave is too fast, and also too small. It's possible to see this type of wave if the wave is large and violent, and if it's filmed with a high-speed camera and then played back in extremely slow motion. --Wjbeaty 07:32, 24 July 2006 (UTC)

I like the question though - is reality instantaneous?

Also - I sometimes wonder, is there is no such thing as a solid in which every atom moves at the same time as every other atom because the universe wants to preserve the speed of light rule?

Also - say I'm standing on earth shining a torch at the moon. The light hits the moon. Then I swing the torch from the moon to an artificial satellite at the same distance from me as the moon. Say too, that I've been working on my reflexes and muscle fitness, and am able to swing the torch at very close to the speed of light. Does this mean the patch of light that swings from moon to artificial satellite moves faster than the speed of light, due to the greater distance covered by the same angle? If it does move faster than the speed of light, then is it allowed to because there's no way of someone on the moon using that patch of light to transmit information to the person on the artificial satellite? Or am I barking up the wrong tree entirely? Adambrowne666 07:46, 24 July 2006 (UTC)

The last option, I'd say. You're seeing the spot of light as an entity. Is it? What defines an entity, and thus if it should be allowed to travel faster than the speed of light? This sounds a bit 'quarky' - a 'tendency to exist'. Or how was that again?

Oh, and consider this. The same beam of light has a width, so it shines on more than one spot on the Moon, so does it exist at different points at the same time? DirkvdM 09:48, 24 July 2006 (UTC)

And another thing, related to the original question. I suppose that density determines how fast a 'push' (such as a sound wave) can travel through a material. So does the speed of light set a limit to how dense a material can be? DirkvdM 09:57, 24 July 2006 (UTC)

Re Adambrowne666's flashlight idea, I've heard of that in almost every Faster Than Light FAQ, and it's generally agreed that it doesn't break the rules for two reasons: The light is still moving, from you, at the same speed, and The people at the other end have no control over its motion. So, as you say, no information is transferred from anyone to anyone else faster than light. Black Carrot 10:21, 24 July 2006 (UTC)

The speed of light doesn't limit density because the wave speed equations that depend on density break down if the speed of the individual material particles becomes relativistic. (They probably break down well before then, actually; most such equations apply only in the limit of small (read: slow) oscillations.) In other words, a material wave travelling faster than light would require some propogating influence (e.g., electrostatic repulsion in most compression waves; particle collisions in gases) or material particle to be travelling faster than light, and that's already impossible without talking about density. --Tardis 03:10, 25 July 2006 (UTC)

They could tie a note to it.

If you're standing on the earth shining a light on the moon, then swing the flashlight over to another body, even if you swing the flashlight at any arbitrary speed, the signal still won't reach the other body until the light has traveled from your flashlight to the other body. There will be a light travel delay just like when you first switched on the flashlight. --198.125.178.207 15:11, 24 July 2006 (UTC)

Really? I don't get it. Isn't the light beam already long enough? Adambrowne666 22:42, 24 July 2006 (UTC)

Well, in a sense, but the light beam isn't a "thing". Once the photons leave the flashlight, they travel pretty much in a straight line. So when you swing the flashlight to point at something else, the photons that have already left the flashlight will continue in a straight line, and will hit whatever you were pointing the flashlight at. The new target of the flashlight won't be illuminated until the photons that have been "fired" toward it get there. —Bkell (talk) 23:43, 24 July 2006 (UTC)

Is reality instantaneous? What is "reality"? All we ever know of the universe is not what "is", but what we perceive there to be. We can never really know what "is". Our perceptions depend on a whole range of factors, such as the speed with which our brains compute and interpret signals from outside. Our perceptions are certainly not instantaneous. But as to whether reality is instantaneous - I would say the question has no meaning and therefore there is no answer, but if it did have a meaning, we could never know the answer. This is veering into religious territory, given that God is said to have called Himself, when speaking to Moses, I am that I am. In that sense, the only thing that "is", is God. You may not believe there is such an entity as God. If not, then nothing at all "is", and therefore the whole notion of "reality" goes out the window. JackofOz

Whew! Hey, sorry, JackofOz, not ignoring you, but I just wanted to mention something about Bkell's comment - I was beginning to think that if information was encoded into the beam of light, say the encoded thoughts of an artificial intelligence, and that beam of light was then swung from moon to artificial satellite, then information WOULD be being transmitted faster than light - but Bkell has cleverly put paid to that. Adambrowne666 05:51, 25 July 2006 (UTC)

It's really just like a hose. If you're spraying person A, then you swing the nozzle to spray person B, person A will still get sprayed for a few seconds, and person B won't get sprayed until a few seconds pass. It's exactly the same for a beam of light. --198.125.178.207 21:44, 25 July 2006 (UTC)

Oh, also, AdamBrowne asked a question up above about a material which responds instantaneously; i.e. an infinitely rigid material. And the answer is that such a thing does not exist. The reason is not because the universe wants to preserve the speed of light as a maximum speed, it's because the laws of physics never result in matter travelling faster than the speed of light. Essentially, photons mediate the relative movement of atoms in a rigid object like a bar. The atoms are held together in the bar by electrostatic interactions. When one atom moves, the electromagnetic field transmits the force from atom to atom, causing the other atoms to move, but not instantaneously; at the speed of electromagnetic wave propagation - at the speed of light! And the reason the bar does not move at the speed of light in response to a force is because the atoms are not massless; they have inertia, which effectively slows down the reaction. --198.125.178.207 21:48, 25 July 2006 (UTC)

Thanks, yeah - I guess I'm belabouring the point about the universe preserving causality by placing these limits not only on photons, but also particles of matter - I'm approaching it telologically, which might be a mistake - your point about the electrostatic forces is well taken; of course, electrostatic forces operate at the speed of light, so it's kind of the same thing as the light beam Adambrowne666 01:59, 26 July 2006 (UTC)

theoretical maximum EER

What is the theoretical maximum EER of an A/C? Assuming 70F inside, and 95F outside. (Or 21C and 35C.) I'm curious how much more improvement is (theoretically) possible in A/C's. 71.199.123.24 07:54, 24 July 2006 (UTC)

From your two temperatures you can work out the maximum possible COP using the equation at Coefficient of performance (COP = Tcold/(Thot-Tcold)). Then use the conversion factor from COP to EER at Seasonal energy efficiency ratio (EER = COP x 3.413). --Heron 17:07, 24 July 2006 (UTC)

Using your equations (and converting C to kelvin) I get a theoretical max of 71.71. Does that seem right? If so, I'm quite amazed at how poor A/C's (with a typical EER of 10-14) are! 71.199.123.24 22:06, 24 July 2006 (UTC)

I agree with your arithmetic. There is a big difference between an ideal Carnot cycle and a practical A/C, but I can't explain why. --Heron 21:39, 27 July 2006 (UTC)

The "i" in Apple

iPod. iMovie. iDVD. iEverything! I skimmed through a couple of articles on Apple stuff, but I didn't find a mention of how or why the omnipresent "i" got its start. I've gotten very curious, and I hope someone may have the answer. Thanks --71.117.43.53 08:02, 24 July 2006 (UTC)

I think it started with the first iMac. -- Koffieyahoo 08:21, 24 July 2006 (UTC)

Thanks for the help, Koffieyahoo; I read through the article and found the answer. In case anyone else wanted to know, the "i" in iMac stands for internet. Probably due to the commercial success of the iMac, Apple adopted the "i" as a prefix for all of its products. Thanks again, Koffieyahoo! --71.117.43.53 08:54, 24 July 2006 (UTC)

iSkimmed through a couple of articles on Apple stuff, but iDidn't find a mention of how or why the omnipresent "i" got its start. iVe gotten very curious, and iHope someone may have the answer There we go, much easier to read. Who knew the internet was so important?

iApplaud you.

Yellow Fever Vaccine & Meningitis A+C

I just need name of some Manufacturer of Yellow Fever Vaccine & Meningitis A+C Vaccine.

Difference between wood charcoal powder and steam coal dust

Can anybody tell me the basic difference between charcoal dust and coal dust produced during mining (i.e. steam coal dust) whether charcoal dust can be used in place of steam coal dust in foundry sand addition?

Nitin Poddar

Retrieved from "http://en.wikipedia.org/wiki/Talk:Coal_dust"

rn lpn rpn what is the difference

Could someone please tell me the difference between a practical nurse, a licenced practical nurse, a registered practical nurse and a registered nurse? Thanks.

See nurse for the difference between RN and LPN, which are the two main categories of nurses consistently recognized at least throughout the US. I have not heard the term RPN before and suspect it is one of the following:

1. No such thing, someone's mistaken or made-up term;
2. A locally devised name for a local program involving a bit of extra training or special certification for LPNs that fall short of full RN licensure, in which case the term has not found wide usage and may still be bound by the legal restrictions of LPN licensure;
3. A status only found in another country with a specific definition; or
4. Something different that I don't know anything about. I would tend to bet on definition 1 or 2, but I could be wrong. If you find a better definition, please let us know. alteripse 00:39, 25 July 2006 (UTC)

See our articles on the topics. Registered Nurses are usually allowed to perform more procedures with less supervision and may receive more education and training than Registered Practical Nurses. (LPN and RPN are terms for similar concepts.) The exact requirements and qualifications vary by jurisdiction. TenOfAllTrades(talk) 00:46, 25 July 2006 (UTC)

Thank-you everyone who responded.

Airoplane

As we know that there is less air at high altitude so also less oxygen. Also now a days an airoplane with more than 200 passengers is flying non stop for more than 12 hrs and the passenger section is sealed and pressurised. What arrangement is made in the air circulation system on the plane so that all passengers get fresh air with sufficient oxygen to breath with normal feeling & not getting suffocated.Is the air inside purified by removing the CO2 and adding oxygen from stocks carried on board ? Thanks. —The preceding unsigned comment was added by 59.95.58.45 (talk • contribs) .

The cabin is fed with fresh compressed air taken from the engines. See bleed air. Femto 14:06, 24 July 2006 (UTC)

Air is partially recycled, partially replaced from outside air. Fresh outside air needs to be compressed and heated, which requires energy, so recycling is used despite health concerns (remember SARS?). Recycled and fresh air are used in about 50/50 proportion, with the entire cabin air replaced with fresh air about every 3-5 minutes. Aviation authorities (e.g. the FAA) have regulations on how air must be refreshed on commercial aircraft. There is some information on this on the net, try googling for something like passenger air recycled, here's one: [2]. Weregerbil 14:15, 24 July 2006 (UTC)

In non smoking planes the air is completely recycled ever 1/2 hour. Philc _T^E_C^I 15:47, 24 July 2006 (UTC)

If your plane is smoking, you may not be very concerned with how often the cabin air is being recycled. kmccoy (talk) 13:26, 27 July 2006 (UTC)

Ironically, in an effort to get the smoke out of the air in planes where smoking is allowed the air is of much better quality than that of non-smoking planes, where you cannot see how dirty the air is, and are therefore not concerned. Philc _T^E_C^I 16:58, 28 July 2006 (UTC)

Life expectancy & such

Medical techlology is advancing very rapidly. Would it be possible, in my lifetime, for the information in my brain to be stored and placed in a new brain/body? I mean, I suspect that my brain is just stored information--would it be possible to map this information, and extract it to a new brain? If so, could we live forever? Sindweller 15:10, 24 July 2006 (UTC)

See, e.g., the article on mind uploading. Another search term for your favorite search engine is "whole brain emulation" (and you may also be interested in things like the technological singularity and some of Ray Kurzweil's writings). It has been discussed quite a bit online and, as far as I know, it's considered theoretically possible but technically very challenging. Some remain optimistic that it will happen in our lifetime though (usual predictions I've seen aim at around or before 2050). Personally I'm a little skeptical as I'm familiar with a lot of the technical challenges, but hopeful :) Digfarenough 16:02, 24 July 2006 (UTC)

Body transplant could also be interresting reading. DirkvdM 19:53, 24 July 2006 (UTC)

And don't forget technological singularity, which is sort of a rapture for geeks. -Quasipalm 02:17, 27 July 2006 (UTC)

Technology

When was the first computer invented?

Slightly before you posted the same question in the Computer/IT Reference Desk. --Kainaw ^(talk) 17:34, 24 July 2006 (UTC)

What a mature, adult response to a simple question. Try reading about Charles Babbage.

Simple? You apparently do not know the full definition of the word computer. This could be:

• When was the first electronic device designed to automate the process of logical calculations was invented?
• When was the first person who performed mathematical calculations (primarily for code-breaking) invented?
• When was the first human-made device for performing calculations invented?
• When was the first concept of using items laying around to calculate something invented?

This is not in any way a simple question. Which is why the questioner should look at the answer to the same question he cross-posted on the computer RD - and get a spanking for cross-posting. --Kainaw ^(talk) 12:36, 25 July 2006 (UTC)

try computer or perhaps abacus--Downunda 22:49, 24 July 2006 (UTC)

As the article on computer and history of computing hardware explain, what is "the first computer" is a matter of technical definitions, and according to one of the more popular definitions there was a device built in 1941 that was a computer, but nobody actually proved it to be so until 1998. --Robert Merkel 10:40, 26 July 2006 (UTC)

pronounce death

Where can I find each State's law concerning who can pronounce death?

Thanks.

• There's a lot of states in the world. It would help if you were more specific. As far as I know pronouncing someone dead can only be done by a physician or trained medical professional, no matter where you are. In some places regular doctors (family doctor/physician) aren't allowed to do this. - Mgm|^(talk) 20:31, 24 July 2006 (UTC)
• If you are referring to the US states, any licensed doctor can pronounce death in every state I'm familiar with. Some states allow RNs, etc. Couldn't find anything comprehensive InvictaHOG 21:22, 24 July 2006 (UTC)

When I used to work as an EMT-B in Massachusetts, I was cleared to pronounce death in cases of lividity, decapitation, and advanced decomposition. It is likely that EMTs in other US states are able to do the same, possibly even in a broader range of situations (MA is known to have very strict rules for EMTs).Tuckerekcut 01:18, 25 July 2006 (UTC)

Those are pretty much the same situations as in NJ (plus "crispy critters": an EMT can pronounce someone who's burnt to a crisp). - Nunh-huh 11:31, 25 July 2006 (UTC)

Wouldn't it take a linguist? DirkvdM 06:21, 25 July 2006 (UTC)

RN = Registered Nurse? EMT = Electro Magnetic Transformer? NJ = New Jersey. MA = Massachusetts.

death can be pronounced by an EMT; emergency medical technician, nurse, doctor based on the following criteria: Decomposition, Decapitation or Transsection if it's in the field. In circumstances involving sudden death in a hospital: The coroner or medical examiner is required to pronounce in order to r/o malpractice, negligence.

So ... for the most part, excepting extreme situations (decapitations and transections for crying out loud) and in some nursing homes in a few states, a doctor must pronounce death. Correct?

Rotational Cooling?

I remember hearing something about something that could cool a can of soda by spinning it at high speed. Does anyone know how that might work? --Zemyla^t 20:12, 24 July 2006 (UTC)

• Probably not. Rotating the can would cause friction (and thus heat) between the can's wall and the moving soda. Besides, even if it's cooled, the soda would burst out of the can as soon as you opened it because the building gas would need to escape, like when you shake it and make a "soda volcano". - Mgm|^(talk) 20:29, 24 July 2006 (UTC)

I've seen devices that (claim to) cool a can/bottle of various beverages rapidly by spinning, but they do the spinning in a cooled environment (refrigerated or evaporative). I think the idea is that spinning causes the contents to mix. Instead of waiting for the temerature gradient from the cool outside to reach the center, the warm center material moves to the cool edge. Since a greater difference in temperature causes faster heat exchange, having "hot stuff" touch "cool outside" would cool faster than "hot stuff" touches "warm stuff" touched "cooler stuff" touches "cool outside". DMacks 00:58, 25 July 2006 (UTC)

So I suppose the spinning axis coincides with the cylinder's axis. But why would the warmer fluid move to the outside? Colder material is denser and thus heavier, so that would move to the outside. DirkvdM 06:27, 25 July 2006 (UTC)

I think it's just mixing (maybe there's some wobble or other off-axis motion too), not a mini-centrifuge. DMacks 08:31, 25 July 2006 (UTC)

• • Your probably remembering hearing about something like the Cooper Cooler trade mark. It either chilled or warmed beverages rapidly. To cool, it required active cooling, but provided a more rapid cooling of the contents by introducing convection within the can through spinning (i.e., the spinning didn't cool the contents, but transmited the heat out to a cold exterior more efficiently). Think of it like a convection oven, which cooks faster because the gases circulate. This system cools (or heats) facter because it causes the cans contents to circulate, allowing it to come more rapidly to equilibrium with a cold (or warm) environment around it. Suspect one can still buy these. John Henry 13:20, 25 July 2006 (UTC)

Presumably completely unrelated, there's the vortex tube which cools by means of a rotating gas flow. Femto 14:31, 25 July 2006 (UTC)

Birds and Trucks

If I weighed a lorry, full of birds sitting on perches, would it weigh the same if all the birds started to hover above their perch?

Ha! A lorry full of lories! Looking at our article on bird flight, it appears that when a bird flies, it exerts a downward force which would probably cancel out the decrease in weight caused by the lifting of the bird. Hyenaste ^(tell) 22:08, 24 July 2006 (UTC)

yes it would, as above. Xcomradex 22:24, 24 July 2006 (UTC)

Yes, a bird lifts itself by pushing air downward with it's wings. So the bird goes up, the air goes down, and the total weight of both is exactly the same. (The bird is no longer pressing on the perch, but the air it's pushing downward is pressing on the bottom of the lorry.) 71.199.123.24 22:45, 24 July 2006 (UTC)

However, if the truck (sorry, lorry) had no floor, I expect the weight would decrease. --Bmk 23:01, 24 July 2006 (UTC)

If the area that the birds were in was enclosed, then the weight of the truck would be the same (over a time average: every bird, when flapping, is exerting a force greater than it's weight to lift it, then it falls a little bit, so the weight of the truck may fluctuate slightly around the average). However, if the truck was open to the environment, the force from the birds may not be exerted on the truck. Think of the flapping action as pressurizing the air below the birds' wings and rareifying the air above it, which causes the birds to be lifted. The high pressure below the wing is likely to be dissipated before it hits the ground (or truck) in a pressure wave. This is why, when a bird flies over your head above a certain height, you won't feel it.Tuckerekcut 01:14, 25 July 2006 (UTC)

If I had a truck full of Tuckerekcuts ... sorry. :) DirkvdM 06:39, 25 July 2006 (UTC)

July 25

Name that syndrome

I was trying to remember the name of a syndrome I read about a few years ago. I remember some of the typical symptoms: late birth (2-3 weeks past due), slightly shorter than normal legs, overly sensitive abdomen (touching the abdomen causes discomfort), and very bad nearsightedness. Does that ring a bell with anyone? --Kainaw ^(talk) 00:25, 25 July 2006 (UTC)

Not really. Couldn't hit anything on OMIM - do you think that it's genetic? InvictaHOG 10:26, 25 July 2006 (UTC)

That is what I was trying to find out. I remembered the syndrome (the "can't touch the chest and belly" part is what stuck in my head). I just couldn't remember if it was genetic or not. --Kainaw ^(talk) 12:31, 25 July 2006 (UTC)

Hurricane to Typhoon

Anyone know the term or name of a tropical cyclone that goes across its basin and regenerates into another storm in a second basin. (e.g. cross International Date Line and becomes a typhoon from the remants of a hurricane) (if you post storm name prefer an example from situation i just told you). Hello32020 02:02, 25 July 2006 (UTC)

Hello, hello, you seem to be mixing several things up, which makes it difficult to understand what you mean. The international dateline runs through one single basin, the Pacific Ocean. Or is this about there being two names for the same phenomenon? DirkvdM 06:58, 25 July 2006 (UTC)

I believe the question is: "Assuming we have 'Typhoons' over the Pacific Ocean and 'Hurricanes' over the Atlantic Ocean, what is the official term for a hurricane that crosses over into the Pacific or a Typhoon that crosses over into the Atlantic?" Hurricanes do hop across Central American into the Pacific. They normally keep their name, such as Hurricane Rita. They do not become Typhoon Rita. Also, once named, they stay named even if they go back and forth between a storm and hurricane. That is why you will see maps that show something like "H Rita...TS Rita...H Rita..." to show it changing between hurricanse and tropical storm. As for crossing the International Date Line, has a named hurricane every gone that far? Once they cross the equator, the winds try to force the storms upward and then eastward, so it would be difficult to keep chugging all the way across the Pacific Ocean. --Kainaw ^(talk) 16:31, 25 July 2006 (UTC)

The north eastern and north western Pacific are considered to be two separate basins in the case of typhoons/hurricanes. -- Koffieyahoo 07:57, 26 July 2006 (UTC)

• In reply to the original question, no, there's no particular term for a hurricane that forms in the East Pacific or the Central Pacific Ocean (where the name for a tropical cyclone is "hurricane") into the Western Pacific (where the name is "typhoon"). If Hurricane Tito crossed the IDL, it would be called Typhoon Tito, but its name doesn't change, nor it gets a particular designation. (And yes, hurricanes have done that in the past. This is not unheard of: Super Typhoon Paka and Super Typhoon Oliwa have done so. There are a few times cyclone names change, but they are listed on our Tropical cyclone article, though. Titoxd^(?!?) 06:51, 26 July 2006 (UTC)

Question about atoms and electrons

My question is what is the power source that keeps electrons in orbit around the nucleus? It's been a long time since college physics for me, and I can't recall if I ever heard a good explanation of this, other than it's quarks and quantum mechanics and stuff.

Yesterday I loaded a pallet with a ton of bricks onto my trailer, it'll be a few days before I can unload it. So in the meantime I got to thinking... all the atoms in my trailer under the pallet are resisting the weight of the bricks, and gravity is pulling the bricks down. Conceivably if I never unloaded the bricks, the atoms in the trailer would go on supporting the bricks until the end of time. The electrons will keep orbiting, the atoms will not ever collapse under the weight of the bricks above them. So what powers that repulsive force that keeps the electrons in their orbits?

Except that everything made by humans eventually decays and falls apart. It might take a very long time, but some time before "the end of time" the trailer and the bricks would disintegrate. Your question relates to the period before that happens. I don't know the answer. Sorry. JackofOz 02:45, 25 July 2006 (UTC)

Hopefully a physicist will respond with a more nuanced answer... but pending that, my understanding is that the electrons aren't really in orbit around the nucleus and therefore don't have to radiate energy like an accelerating body. They just sit there... but since they're waveforms as much as particles, they sit in orbitals rather than at single defined points. --Allen 02:56, 25 July 2006 (UTC)

At the quantum level I think it boils down to the weak force and strong force. Gravity doesn't even exist at the quantum level. Emmett5 03:04, 25 July 2006 (UTC)

Sorry, try again next time. The answer has nothing to do with the strong or weak nuclear forces. Allen's answer is mostly correct, except that electrons do radiate energy — but only when they're in an excited state. Because of quantum mechanics and the uncertainty principle, the electron has a spatial distribution even in the lowest possible state. It can't possibly "fall into" the nucleus because that would restrict its position to an exact value, and therefore its momentum would become totally undefined and it would shoot right back out. —Keenan Pepper 03:15, 25 July 2006 (UTC)

Playing around with this applet might help you get some intuitive grasp of it. If you try to confine the particle's position to a narrow spike, it explodes outward and after a short time you have no idea where it is. —Keenan Pepper 03:20, 25 July 2006 (UTC)

[Note: posted after an edit conflict with the terser Keenan Pepper. Sorry for the duplication, but hopefully the longer explanations help someone.]

It doesn't take energy to resist a force; it takes energy to, well, give something more energy. So it takes energy to lift your pallet (giving it more gravitational potential energy), or to throw your pallet (giving it (more) kinetic energy), or to heat it (giving it more thermal energy, which boils down to electric potential energy and kinetic energy of particles within it). You're not doing any of those things, so no energy is required. Put another way: if all those atoms were "doing something" or exerting themselves in some way, where would their efforts go? Certainly if they were releasing energy somehow, it would have to go somewhere, and nothing's happening.

Put yet another way: consider the alternative. Suppose that the pallet, as you intuitively suspect, is in danger of having its "power" to hold the bricks fail. What then? Presumably the bricks fall, but the only place for them to fall is through the material of the pallet (or the ground, or...). Because atoms are basically rigid (because of the Pauli exclusion principle and the Heisenberg uncertainty principle, which when applied to highly compressed atoms requires them to have a lot of energy), they would have to overlap to accomplish this, and this would require more energy to arrange (i.e. to fight all the electrical repulsion between like charges). So the answer is that the bricks cannot fall because they do not have enough energy, not that they manage to stay up because they have some to spare. (With enough energy, the bricks could in fact merge with the pallet. But this amount of energy corresponds to vaporizing both objects and squishing them together, or (more extremely) the creation of degenerate matter or so.)

I think this confusion arises so commonly (although often in other contexts) because, due to what could be called a design flaw in animal muscles, we must exert energy to maintain our body in a non-neutral position, even if we are not applying that energy to anything else (think about holding your foot off the floor forever while seated). This is because there is some slippage in muscle cells under load (even the load of our own weight), and they must continually reassert themselves to maintain their position. So intuitively, we think of energy as force multiplied by time — how hard we strain times how long we do it. But all the energy that we expend as we tire holding our leg up just goes into heating the muscle as the cells slip and regain their position repeatedly. Mechanically — that is, treating our body as a black box — the energy is force times distance instead, and has no dependence on how long we (or the pallet) must hold things up.

On what is really an unrelated note, it is noteworthy how quantum mechanics explains how an "orbiting electron" avoids radiating as accelerating charges normally do (e.g., in a radio tower, where electrons rushing up and down generate radio waves). Quantum mechanically, the electrons are not in fact moving, but are simply in the vicinity of the nucleus, never going anywhere (and having no classical motion around it either). They still get to have angular momentum (as do normal rotating objects), but because they are not localized they can "rotate" in this sense without accelerating (remember that rotating objects classically undergo centripetal acceleration).

Finally, (to Emmitt5) neither the weak nor strong nuclear forces are involved in this situation; all human experience outside of nuclear reactors or so is the gravitational and electromagnetic interactions (the other two forces) entirely. And gravity exists everywhere; typically on such small scales it is negligible, but it controls the larger organization. Perhaps what you are thinking about is the current theoretical problems unifying gravitation and quantum theory. Hope this helps. --Tardis 03:40, 25 July 2006 (UTC)

Bravo Tardis - you hit the nail on the head. It is often confusing that muscles must use energy continuously to exert a stationary force, but that is due to the molecular dynamics within the muscle cells; applying a stationary force does not consume energy over time - it is only force along a distance that does work. --Bmk 05:56, 25 July 2006 (UTC)

Yes, thank you Tardis, you understood the question I was trying to ask very well, better than I did clearly! You've given me some more terms to look up, that'll keep me busy for a while.

All of the atoms on the trailer have a random component. There is a statistical probablility the one atom supporting the most weight will gather enough energy to 'come loose', or gain enough energy to overcome the activation energy of seperating itself from the bonds holding it in place and become a 'free agent' so to speak. At that time the downward force on it will tend to cause it to have a higher chance of moving downward than upward. When that happens the load will drop down a fraction of an atomic diameter. The same thing can happen to other atoms which are not supporting the most weight, but the effect will be less pronounced. If you wait long enough, the trailer will unload itself, so just go have a beer. You will have an opportunity for lots of beers.

Unit conversions (title added)

can anyone tell me what 9 kg of lpg equates to in m3, what does 1m3 of natural gas equate to in kg and is it possible to co-relate the two, thanks``` Hatch

What's the temperature and pressure? —Keenan Pepper 03:24, 25 July 2006 (UTC)

hmm, seems you've added a pressure comment since i clicked edit... anyway, hatch, try ideal gas law. you need a few parameters you haven't given. Xcomradex 03:28, 25 July 2006 (UTC)

Nitpick: Keenan's comment was added after the last time you downloaded this page. When you clicked 'edit' determines whether there was an edit conflict. DirkvdM 06:57, 25 July 2006 (UTC)

thanks sorry about ending up on someone else's item

Where did the hemp go on my farm?

I live in Canada, but my family owns a some land in southern Italy that my granparents used to farm. We have went there a few times, and my dad told stories of his childhood. He has told me several times that our land had lots of marijuana on it. He remembers using it for rope, he also remembers others in the around using it to get high. He has told me when he was a kid he remembered many farms and even just land on the roadside was teaming with marijuana, now the land is devoid of it. No one in the area can remember anyone actually spraying our land (it was left unkept for years), and this has happened to the whole state anyways (public land, huge sections of unmaintained forests, personal land ect). So if no one knows of someone actually physically removing this plant, then how else could it have been done? Some kind of chemical I assume? Anyone have an explanation? In a place like southern italy that still has massive amounts of unused bush land, isn't removing this plant from an entire province a serious undertaking?

Hanez --216.211.78.176 04:01, 25 July 2006 (UTC)

PS I placed this question in the Science category because I assume this was done with a chemical...

Good one. Loads of hemp was grown in Europe for centuries. It was used for all sorts of purposes, most notably the ropes that were used on the boats that explored the world, so it was extremely important. And it's a weed and weeds are indeed hard to get rid of. So, indeed, it must have survived in the wild. One thing I can think of is that it is a light-loving plant (what's that called in English?), so it grows in open fields, is therefore very visible and may have been over-harvested by smokers (you have to harvest it before it pollinates). But the cannabis variety used for ropes is not the best for marijuana. Marijuana is the name for the drug, not the plant. The highest concentrations of THC are found in the flowers, but for rope you need long fibres, meaning long internodes, so you get fewer flowers. And those few flowers contain less THC, so it's not very potent as a drug. So that makes the over-harvesting unlikely.

But there's another possible answer: maybe this variety was bred so specifically for fibre, resulting in so few flowers that it took human intervention to pollinate. Bummer. :)

By the way, here's a story I read once. The writer of this story was in a bar in Bavaria in the very conservative south of Germany in the 70's or thereabouts. At one table there were a bunch of hippies, at another table a bunch of elderly locals. The locals were talking about those hippies, about 'kids these days', that sort of thing, and at one point one says "I bet they smoke marijuana too", upon which another asks "What is marijuana anyway?". So the writer turns around and says "It's hemp." "What do you mean it's hemp, we used to smoke that when we were kids." "Yes, and didn't you feel anything?" "Yes of course, that's what we smoked it for." "Well, that's marijuana." A nice example of preconception based on misinformation.

So the rope-hemp isn't quite as potent. But that doesn't mean you won't feel anything if you smoke it. It's just a much milder high. I've heard it said that illegality has led to weed that is way too strong (more compact and thus easier to transport), as a result of which people have forgotten what a nice high is like. Especially Dutch weed is now so potent that some say it should be classified as a hard drug. And indeed I only buy the cheapest stuff and smoke very small quantities of it. I wish there were milder varieties. Another good reason to end the illegality. DirkvdM 07:18, 25 July 2006 (UTC)

Look up 'wild hemp' on Google. It has a very small native region in Asia. All of the rest of the wild hemp, called 'ditch weed' in the US, is a leftover from cultivation. The US spends millions to destroy wild hemp (which has almost no THC!). That may have happened in Italy as well, or the hemp might have just died out. Extensive fibre-hemp cultivation has now started up in Canada. --Zeizmic 12:15, 25 July 2006 (UTC)

animals

Can a Salamander hurt a dog? Do salamanders have any sort of 'venom' they could use as a defensive mechanism?Possibly a 'Dusky Salamander' species. It has blackish-brown (no spotting) coloring and is approximately 2.5 inches in length. We are living in a northern suburb of Minnesota. I have a 15# shitzu-poodle. Thank you, in advance, for your efforts in finding the answers to my questions.--68.187.149.254 05:13, 25 July 2006 (UTC)

Salamanders aren't poisonous. The only vaguely similar poisonous thing is a gila monster, but that doesn't sound similar enough. There aren't even any other poisonous lizards from anywhere in the world that could be an escaped pet (except komodo dragons, and they are a bit bigger). However, if the dog ate it, and the dog is now sick, there could be several reasons, including the possibility that the salander had just eaten poison. If the dog is sick, take it to a veterinarian right away. If it isn't sick, probably nothing to worry about. Notinasnaid 08:02, 25 July 2006 (UTC)

Im pretty sure i heard of a deadly poisonous lizard in the desert somewhere. Some travelers boiled one by mistake in their coffee and both died.

There are poisonous newts, and newts are salamanders. They are not venomous, as venom is injected poison; to be poisoned by a newt, one must eat it. See this link for some good references. I remember seeing a piece on a TV program about the story of the camper killed when a newt (probably a rough-skinned newt) crawled into his coffee pot and was boiled along with the beans; however, I couldn't find any reliable references from Google.

At any rate, if you think your dog has been playing with or has eaten a newt, get veterinary care right away. --Ginkgo100 ^{talk · contribs · e@} 20:41, 26 July 2006 (UTC)

Chemical Composition of CEP 2563

Can You Give me the Chemical Structure Of the CEP 2563 as Tyrosine Kinase Inhibitor.

Looks like it the compound in the graphical abstract of this article:

"Prodrug esters of the indolocarbazole CEP-751 (KT-6587)". doi:10.1016/S0960-894X(98)00328-X. {{cite journal}}: Cite journal requires |journal= (help)

DMacks 05:59, 25 July 2006 (UTC)

The Wolrd bank

I need the major criticism points about the World Bank and the developing countries debt, And the defense that was taken against those accusations. As well as, the proposals given to form policies to solve those issues.

ps: you can always guide me to useful websites or links in regard of this topic.

thanks

Salloya La Douce

Hi. Might i suggest you start with the World Bank article, specifically the section on criticsm and some of the references therein (e.g. [3] [4] [5])

Flexible PVC products

I would like to increase the tensile strength of soft and flexible PVC products. ( eg. like rubber band) The processing method is through extrusion.

How can I crease the tensile strength to the product. What should I added during processing of PVC

Expecting your reply at the earliest--220.225.124.50 06:00, 25 July 2006 (UTC) L . srinivasan

Intestinal Worms

How long can intestinal worms exist in a body? In this case there are no major symptoms besides occasional "stomach discomfort" that has lasted for nearly a year.

Successful parasites can exist for the lifetime of the host. So can delusions of parasitism. alteripse 10:29, 25 July 2006 (UTC)

Just a note: Our GI clinic gets people every day complaining of intestinal worms. It is very rare that they have worms. They just have loose bowels. They normally explain it to the patient by saying, "Your intestines are lined with little fingers that grab and push the waste through. If it is too watery, they grab and pull on each other instead of grabbing and pulling on the waste. Because of the vast number of nerve endings in the area, this can cause extreme pain that radiates all the way up into the chest and arms. So, eat more ruffage." --Kainaw ^(talk) 16:41, 25 July 2006 (UTC)

It's almost impossible to prove that someone does NOT have intertinal worms because:

Lack of evidence is not evidence of lack

The only way to be absolutely sure is to examine every square millimetre of someone's intestine. Ohanian 22:54, 25 July 2006 (UTC)

After they are dead, of course? alteripse 10:19, 26 July 2006 (UTC)

But at the same time, if a doctor finds nothing wrong with you besides loose bowels, and loose bowels adequately explain your symptoms, why assume you have magical worms which evade detection but give no additional symptoms? Having said that, the anon should probably make an appointment with a doctor who can actually look at them and make a diagnosis and recommendations. Skittle 15:25, 26 July 2006 (UTC)

It should very much be possible to prove that someone does not have intestinal worms at least to reasonable standards by checking for tapeworm DNAin the stool via Polymerase Chain Reaction. Of course, you'd need a reasonably specific DNA sequence, but that should be doable. Given the sensitivity of PCR, if a negative result turns up several times on several different sequences, you can be pretty sure there are no worms. --OliverH 19:36, 29 July 2006 (UTC)

To answer the original question, I believe tapeworms can live indefinitely inside a person without killing them. StuRat 03:21, 27 July 2006 (UTC)

Formula info.

I would like to find a formula, if it exists, regarding the relationship between water's boiling point and pressure. For example I would like to find out, what is the temperature for witch the water stars to boil at 150 mbar.

Thank you and best regards, Alex

• I think you have better luck if you tried finding a graph. - Mgm|^(talk) 13:29, 25 July 2006 (UTC)

I agree - I've never seen any kind of formula, piecewise or otherwise. Here's a link to a phase diagram for water (which incidentally is what you should search for in google). This is just one of many - I just picked the first hit. Wait, hold the phone! It turns out that if you hold the mouse over the phase-change lines in the diagram, it shows a polynomial fit equation for the line! Have fun. --Bmk 14:48, 25 July 2006 (UTC)

Water and ice questions.

1. What is the state of water at 100°C?

2. Why does ice float on water?

3. Are there other substances whose solid state float on its liquid state?

Thanks in advance. --Siddhant 11:35, 25 July 2006 (UTC)

• Please do not ask homework questions. 1. See water or phase (chemistry). 2. see flotation and density. With a little luck, you should be able to answer 3 after reading that. - Mgm|^(talk) 13:27, 25 July 2006 (UTC)

For #3, have there been experiments with diamonds and liquid carbon? --Kainaw ^(talk) 16:53, 25 July 2006 (UTC)

For #3, you don't need to get some complicated. Any material that expands when it cools will float on it's liquid state. There aren't many of them, but they do exist. Type metal for example expands, (although I haven't checked if the liquid state is more dense, perhaps it expand only during the solid state). 71.199.123.24 17:55, 25 July 2006 (UTC)

That #1 Does not have sufficent information to be answered. Sindweller 18:14, 25 July 2006 (UTC)

how to anliyze talc(3MgO4SiO2H2O)

what methods can we use to anlyze : - the brightness of talc - the quantity of Magnesium and Silica can we increase the brightness of talc? how if you know the way you can send an email to <removed email addess> or mobile on <removed cell phone number>. it is for my collage please

Why are you making a collage about analysing talc? I don't know that it'd be very interesting to look at. Perhaps you are putting talc onto your collage, in which case increasing the brightness (I suppose) might be useful. However, as brightness is a measure of the amount of light given off an object, talc has none at all. 89.138.69.138 08:43, 26 July 2006 (UTC)

Galaxy/Balck hole

I have heard on several occasions that galaxies are believed to orbit around supermassive black holes, and some other things, in which case I have several questions.

1. Will the whole galaxy fall intothe black hole eventually?
2. Why are galaxies never depicted with jets emitted along the z-axis, where smaller black holes do when they have accumulated a Accretion disc, and it is well established that small black holes (by comparison) can emit ones that span our galaxies height?
3. Do black holes last forever?
4. If they do, will the universe not eventually end up as one huge black whole, or atleast a massive pool of black holes moving apart?
5. Also, can stars exist outside galaxies?

Thank you Philc _T^E_C^I 18:10, 25 July 2006 (UTC)

1. Pretty much. Some rogue stars could escape, however.
2. Don't know. Supermassive black hole notes that such black holes have many properties differing from stellar-sized versions, perhaps that's why?
3. Current theory suggests "no". See Hawking radiation for small ones and heat death of the universe for the big ones.
4. From the second link immediately above, theory suggests that the universe's matter will end up as all (or virtually all) black holes. Then it'll change.
5. Yep. See Intergalactic Wanderer for examples.

— Lomn | Talk 18:24, 25 July 2006 (UTC)

Have you read our article on Supermassive Black Hole Sindweller 19:20, 25 July 2006 (UTC)

For question 2, such jets exist and are the most luminous known things in the universe. In most galaxies the central supermassive black hole is quiescent, having consumed all significant surrounding matter. But occasionally they get matter to feed on, flaring up as a quasar or a blazar. Weregerbil 20:15, 25 July 2006 (UTC)

Surely every time they feed, the additional matter means there garivitational strength increases and so more matter is placed within they're reach, so why don't they consume the whole galaxy relatively quickly? Philc _T^E_C^I 20:48, 25 July 2006 (UTC)

The gravitational force of the black hole increases, yes — but not the gravitational force of the system. There's just as much mass in close proximity to the black hole after "feeding" as there was before. — Lomn | Talk 20:52, 25 July 2006 (UTC)

Yeh that is true. As a readjustment of the question in light of your point. Does the reorientation of the mass affect the gravity of the system at all. Philc _T^E_C^I 22:13, 25 July 2006 (UTC)

From what I've read about quasars, as the center becomes more massive, it collapses tighter on itself. Add to this the reduction of mass around it, it spins faster - like a figure skater spinning faster when she pulls her arms in. That pushes the matter in the system outward, which slows down the spin - but also separates it from the deathly edge of the black hole. As it slows down, it creeps back toward the black hole and the whole cycle begins again. Also, on top of that balance, there is the theory that the black hole is losing mass all the time by radiating energy outward - isn't that Hawking's theory?? I don't know - I'm just a computer programmer. --Kainaw ^(talk) 16:11, 26 July 2006 (UTC)

I don't see any reason why an equilibrium can't be eventually reached where all stars are in stable orbits about a central black hole, just like planets orbiting a central star or moons orbiting a central planet. StuRat 03:09, 27 July 2006 (UTC)

Ointment Battle

If hydrocortisone and neosporin were to get into a fight, who would win? 199.201.168.100 19:18, 25 July 2006 (UTC)

List of JAG episodes. Melchoir 21:04, 25 July 2006 (UTC)

Huh? As for the fight, I suppose it would depend on whether allergens or bacteria were present. --Ginkgo100 ^{talk · contribs · e@} 20:01, 27 July 2006 (UTC)

Neosporin, of course! But only if it were an endurance battle, since neosporin is petroleum based, and hydrocortisone is not. --Teh Janitor 03:52, 30 July 2006 (UTC)

Will the Universe tend towards a single point

I was reading up about the N-body_problem and found it quite interesting. I made a small program that would display the interaction between two bodies of equal mass with the intention of generalising it for many bodies. When I ran the program with one fixed body and one body effected by gravity everything worked as expected,I got an orbit that was an infinite loop. However when I allowed both bodies to be effected by each others gravity every starting condition that I tried caused the bodies to collide. They oscillated round a centre point in smaller and smaller elipsces.

I was under the impression that it was possible to set up a stable gravitational system. However these very limited results seem to say they opposite.

Either theres a bug in my program (quite likely) or its not possible to set up a stable two body gravitational system (and by extension a stable n body system).

So, is it possible to set up a stable gravitational system? If so would anyone be able to explain how, ideally with a plot of the two bodies, every plot I've seen so far only show one body moving. Thanks for the help

Oh yes. In fact, if two bodies aren't on an immediate collision course, and they aren't moving fast enough to "escape" each other's gravity, they always enter a stable orbit -- in fact, a closed orbit. See Two-body problem. Melchoir 22:16, 25 July 2006 (UTC)

It sounds like your model system is 'leaking' kinetic energy through the accumulation of small rounding errors. There will be a limit to how far forward you can project in time before these errors become overwhelming. TenOfAllTrades(talk) 22:31, 25 July 2006 (UTC)

Without seeing the program you've written, I can't say for sure, but I'm almost certain you are experiencing round-off error. Basically, at every time step (I'm assuming you used a simple kind of discrete time step algorithm), the positions and speeds and accelerations of the two bodies are subject to small errors, which build up over time and result in macroscopically unphysical behavior. Melchoir is quite correct that two point particles cannot collide unless they are initially on the degenerate orbit of direct incidence - the zero angular momentum orbit, and otherwise must form either stable orbits or escape from each other to infinity. Of course, if they are particles with positive finite radius, they can, and do collide in real life. This is all classical gravitational physics...i don't really have the willpower to think about general relativity right now. (ps - tenofalltrades beat me to the answer, but i'm posting anyways) --Bmk 22:36, 25 July 2006 (UTC)

And taking look at nature, there are literally millions of binary star systems out there, where two stars orbit around each other in a stable configuration. And to assuage Bmk's fears, it works pretty much the same way in general relativity, with the small exception that ultra-massive objects (eg neutron stars, black holes) in a close orbit will radiate gravitational waves, which, if I remember my physics classes correctly, should cause the system to gradually lose energy and the bodies to spiral towards each other. However, this effect is very weak, and even two neutron stars orbiting each other will be able to maintain their configuration for a long time. — QuantumEleven 06:53, 26 July 2006 (UTC)

Eating raw mushrooms

Are any mushrooms safe to eat raw? Knowing that there are plenty which are outright poisonous, and a few which must be cooked for safety. I am wondering specifically about store-bought varieties which are commonly served raw.

See Talk:Edible_mushroom for additional links, resources, and discussion. ∴ here…♠ 22:23, 25 July 2006 (UTC)

What do you mean? You pretty much answered your own question with "I am wondering specifically about store-bought varieties which are commonly served raw." Wizrdwarts (T|C|E) 01:57, 26 July 2006 (UTC)

I didn't even know there were any mushrooms that were safe to eat, but only when cooked. Are there any like that besides the false morel? Button mushrooms are perfectly safe to eat raw. —Keenan Pepper 02:54, 26 July 2006 (UTC)

I doubt that any types of so-called 'edible' mushrooms would be sold at reputable stores if they weren't completely edible, via any conventional preparation method.--Anchoress 02:59, 26 July 2006 (UTC)

I've never heard of mushrooms that must be cooked for safety, but as Anchoress implied, I'm sure any store would warn you before selling you one. Again, I've purchased and eaten my fair share of mushrooms - there are hundreds of edible varieties, and I've never seen one that needed to be cooked for it to be safe. --Bmk 03:35, 26 July 2006 (UTC)

Don't know what they're called, but there's a mushroom that looks exactly the same as enokitake. The "false enokitake" can cause diarrhea if it isn't cooked properly. --Kjoonlee 08:03, 26 July 2006 (UTC)

I think slippery jacks (mock porcinis - aka boletas) are slightly poisonous raw, and slightly less so, perhaps fully edible - though they don't taste particularly good and i did feel a bit sick after eating one - when thoroughly cooked.

Also note that many 'shrooms are grown in manure, so cooking them is a good idea (to kill any little nasties living in the manure). StuRat 03:00, 27 July 2006 (UTC)

Awesome article Mushroom picking in Slavic culture says that Boletus edulis and Russula vesca could be eaten raw. I wouldn't recommend it though :)  Grue  08:12, 29 July 2006 (UTC)

Even True morels should be cooked, otherwise they can cause stomach problems(vomiting, nausea, diahrea, cramps) . If you have eaten them raw yourself without any problems go rite ahead, but don't serve them to anyone else raw. Especially with alcohol.----Aaron

July 26

Talking starling video on YouTube

http://www.youtube.com/watch?v=VpYHYrMnffc&search=starling

What do you guys think of this? I'd heard that pet starlings were capable of learning a few words - but this one seems particularly talented. Just how intelligent are starlings in comparison to other talking birds? I guess we see so many of them that we don't really pay any attention to them. --Kurt Shaped Box 01:04, 26 July 2006 (UTC)

It's fake. Watch the bird when it whistles. It doesn't open it's mouth, just makes noise. Also watch the throat feathers when it whistles - they move quite a bit.

Now compare to talking - every single time it opens it's mouth you hear words - but if you notice, the feathers don't always move! And birds don't need to move their mouth to talk, yet here, ONLY when it opens it's mouth - and EVERY time, it opens it's mouth, you hear talking.

And finally listen carefully to the words it's saying - every single time, it sounds EXACTLY the same, as if a computer was playing a sound file. If it was real it would vary a little. 71.199.123.24 21:31, 27 July 2006 (UTC)

Our starling doesn't talk but does impressions of twenty birds, plus the  dog down the road and Curly of the three Stooges WOOB WOOB WOOB WOOB WOOOO. He performs every morning about 6:30 and has been doing this for 8 years.

Should I turn off my computer during a thunderstorm?

I get pretty annoyed when I have to unplug the computer during a thunderstorm, and I want to know if this is really necessary. Here this concept is talked about and most of the answers are yes. But I want to know what are the chances of this happening? Would this happen once in a hundred thunderstorms? Once in a thousand? Is it as important to do this as it is important to wear a bike helmet? Or as important as "do not lay, sit or sleep on this electric blanket" or "Do not exceed the weight limit of 215 lb on this trampoline"? --Jonathan ^talk 01:42, 26 July 2006 (UTC)

When you unplug your computer in a thunderstorm, it has nothing to do with your personal safety - it's for the safety of your computer. Wearing a bike helmet, or not breaking your neck on a trampoline are issues of personal safety, so it's hard to compare their relative importance; I assume your head is priceless to you compared to your computer... in terms of damage to your computer, if you use a good surge protector, your computer has a decent chance of surviving a lightning-related surge. In terms of the frequency of surges, I don't know, but they do occur. --Bmk 03:23, 26 July 2006 (UTC)

A friend of mine had their hard disk fried during a thunderstorm about six months back. it's a good move to unplug. Grutness...wha? 03:30, 26 July 2006 (UTC)

Unless you're the type that doesn't mind losing loads of important data, then yes you should turn it off. If you invest in a good UPS, you should be safe leaving it on if there are just a few small rumbles of thunder beacause the computer will remain on for a few minutes even if you lose power. I would still advise unplugging everything though if there are severe storms in the area. I once saw an episode of MythBusters that dealt with questions of this sort and if I recall correctly, they determined that you really don't want to be in contact with any electrical equipment if there are severe thunderstorms nearby. --Nebular110 04:24, 26 July 2006 (UTC)

If you don't like losing important data, you should have it backed up for precisely such an eventuality. - Mgm|^(talk) 13:24, 26 July 2006 (UTC)

Lightning can induce a sudden voltage on the phone wires that can blow out a chip in a modem. Not so much as to be dangerous to a human, but exceeding the voltages you can put on a chip. I've seen it happen. So, remove the phone wire from the modem, if you have a modem. Logically it would seem the same would apply to your DSL "modem", but I don't have direct experience of that. --GangofOne 04:55, 26 July 2006 (UTC)

It also depends on where you live. In the countryside you often have long overhead telephone and electrical distribution lines. Those are more susceptible to induction from lightning than shorter underground cables used in cities. Also trees that brush against overhead lines and fall down on them during storms cause grief, which doesn't happen with cables. But if you live out in the sticks you already knew this :-) Weregerbil 08:07, 26 July 2006 (UTC)

This may also depend on the country you're in. If electricity and telephone lines or cables are supplied by private companies (that actually compete) then if protection against this is so costly that it noticeably increases the price any company that does this will go out of business because people generally focus more on short term gain. I don't know if this is the case, but it sounds plausible.

Also, if there is such a risk, then that is a good argument to have backups on different media, such as on dvd's (in a different location if possible) or possibly on hard disks on a separate (old) computer that isn't normally connected. DirkvdM 09:31, 26 July 2006 (UTC)

AAAHHH! I just found out too late that those new LCD tv's are remarkably sensitive to a little speck of distant lightning. I had put surge protectors on all the computers, but not on the little tv in the exercise room. I then read that sometimes you can find the resistor that fried, but this one has all surface mount stuff, and the inside appears to be working perfectly, except it doesn't work! I'm now wondering about a happy way to ditch it.... --Zeizmic 12:05, 26 July 2006 (UTC)

Okay, thanks for all the answers. I was mostly trying to find an excuse to keep the computers running, but seeing as I do have backups for most of my important files, I might be okay. --Jonathan ^talk 12:18, 26 July 2006 (UTC)

Many people purchase a spike protector for the computer, including a port for the phone line. This protects against voltage spikes, but not against an actual lightning strike.

I had a modem get fried during a thunderstorm once, so I'd say it's not all that rare. StuRat 02:53, 27 July 2006 (UTC)

Mr Wheeler, of Wheeler's formula for inductance fame

What is his full name? What years was he born and died? What year did he come up with the Wheeler's formula for inductance. Any other information on his biography?

Gary Burger

I can't find much centralized data online, but after some intrepid searching, here's something to get you started - the citation for the paper in which he developed the Wheeler formula for inductance:

• Harold A. Wheeler, "Simple Inductance Formulas for Radio Coils," Proceedings of the I.R.E., vol. 16, no. 10, October 1928

Hope it helps --Bmk 06:32, 26 July 2006 (UTC)

Lizard

What type of lizard has a black body with yellow spots?

The kind at Camp Green Lake are Bearded Dragons. Hyenaste ^(tell) 05:19, 26 July 2006 (UTC)

Salamanders? But they are amphibians.....Paul venter 18:38, 26 July 2006 (UTC)

What's the Deal With Water Boiling at Altitude?

I was under the impression that it boils at a lower temp, but I've also heard from somebody about it taking longer to reach boiling point. The two seem incongruous to me. Any answers? And why?

The lower the air pressure, the lower the boiling point, therefore, the higher the altitude, the lower the boiling point (generally). I don't know about it actually taking longer to boil, maybe someone else knows about that. It might have to do with transfer rate of heat, I don't know.--Anchoress 05:21, 26 July 2006 (UTC)

It is illogical that it would take longer to reach the boiling point. However, food cooked at higher altitudes will take longer to cook since it is cooking at a lower temperature. Hyenaste ^(tell) 05:25, 26 July 2006 (UTC)

It makes sense that a substance would reach the STP boiling point after a longer time, though, as the extra heat would be "absorbed" by the enthalpy of vaporization, leading to cooling by evaporation. That said, the liquid wouldn't be at STP, so that doesn't really apply. Titoxd^(?!?) 05:34, 26 July 2006 (UTC)

That's what i thought. I remember that you can't fully cook some kinds of beans up at high altitude because the proteins don't break down until you reach a higher temperature than the water can go (unless in a pressure cooker.) Thanks

The deal is, once the water hits the boiling point, whatever that might be at a given pressure, all extra heat goes into energy of vaporization; you can't heat a liquid hotter than its boiling point! Therefore, if the boiling point is low somewhere (such as at a high altitude), the temperature at which you can cook food in the water is lower, so it takes longer to cook. --Bmk 06:36, 26 July 2006 (UTC)

Not always: you can superheat water in a microwave (of course, it more or less explodes when you then disturb it, so it's useless for cooking anyway). — Lomn | Talk 14:03, 26 July 2006 (UTC)

Or use a pressure cooker...

Silly question?... but

What stops something from going faster than light? I am reading a physics book so I wont fail while taking the ap class in my highschool along with 5 other killer courses, and i came upon the formula for the fairly obvious (to us now) fact that a falling object accelerates at a constant rate (in other words its velocity continues to grow with time.) What is to theoretically stop a highly compact mass dropped from the farthest edge of the gravitational pull of a very heavy, compact planet with little wind resistance (friction, etc) of any kind to overcome the speed of light? What is the theory behind this "cosmic speed limit" and why isnt the hypothetical situation a major physics theory clash?

A lot of things can move faster than light, provided they have no mass. A simple example would be the intersection of 2 lines forming an acute angle and moving apart at relativistic speeds or lower; with a very small angle of intersection even small speeds would be sufficient Paul venter 18:35, 26 July 2006 (UTC)

The hypothetical situation doesn't happen because of a few things. Firstly, the acceleration due to gravity isn't a constant, it's actually inversely proportional to the square of the distance from the centre of mass (according to Newtonian physics, at least - if you want to make things accurate you need to work in General Relativity, to which Newtonian physics is a reasonable approximation for many things but not perfect), so to even get the amount of acceleration you're thinking of, you'd need a very large mass, and a reasonable distance. Secondly, and more importantly, in relativity, the "effective" inertial mass of an object (ie. how hard it is to accelerate) increases with velocity, so that as an object's velocity approaches the speed of light, it becomes harder and harder to accelerate, and its mass approaches infinity. Much of the physics you would be learning at high school is based on approximations that only work in certain situations - low velocity, no particularly strong gravitational fields, and so forth. (Oh, and don't worry, as far as questions go, it's far from silly. If you're used to "traditional" physics, relativity and quantum mechanics are often quite counter-intuitive.) Confusing Manifestation 05:51, 26 July 2006 (UTC)

IANAAP (I am not an astrophysicist), but my understanding was that, since mass increases with speed, the speed of light is like the balancing point whereupon an object's increasing mass prevents it from going any faster. Or was it something more specific, as in anything going faster than the speed of light would be infinitely massive? I'm mixing up my Star Trek Physics with my real physics lol.--Anchoress 09:12, 26 July 2006 (UTC)

IAAAP (I am an Astrophysicist). I would recommend reading the general relativity article. You are pretty much along the correct lines (at least regarding changing mass). The relative mass of an object when travelling relatively to an observer is given by the rest mass multiplied by the Lorentz factor, gamma. which is equal to one divided by the square route of one minus the relative velocity squared over the speed of light on a vacuum squared (it's easier to see when written down properly). The upshot of this is that a body travelling at the speed of light in a vacuum (relative to an observer) would have an infinite mass (and therefore have required an infinite amount of energy to get there); if it were to travel faster than the speed of light it would have an imaginary mass - which is why it can't happen.

I read somewhere that light particles are really zero-time particles; that from their point of veiw, they don't exist at all. Don't ask me how that works, but that might be a clue as to why they always have to move so fast and why it's such a weird substance. --Jonathan ^talk 12:24, 26 July 2006 (UTC)

This is true Jonathan. There should be several good articles about explaining the exact mechanisms of this phenomenon so I wont go into a full explanation of them here. The upshot is that time flows at different rates for comoving observers. To calculate the time passed for an body relative to an observer, the observer must measure the time interval, and divide it by the Lorentz factor $1/sqrt(1-v^{2}/c^{2})$ where v is the speed of the moving body (relative to the observer). From this you can see that when v=c time will cease to pass for the moving body (relative to the observer). This effect is knows as time dilation.
Going hand in hand with time dilation is the phenomenon of length contraction. Distances (in the direction of movement) of a body will appear shorter for an observer. The method for calculating this is the same as with time dilation except that time is replaces with distance.
Taking both of these phenomena into account, if you were to ride on a photon you would observe everything to ever happen in the whole history of the Universe happen at exactly the same instant and at exactly the same (infinitely small) place!

weather - temperature change in same area

(moved from the Help Desk) I would like to know what causes a noticeable temperature change in 2 or 3 days in the same area. Other than temperature all other weather conitions appear the same - one period to the next.

Thank You - bl —The preceding unsigned comment was added by 4.158.195.191 (talk • contribs) 21:39, 19 July 2006 (UTC)

Weather at nearby locations, such as warm or cold fronts moving through an area, will affect local temperature (presumably you aren't taking that into account when you say "all other weather conditions appear the same," but I might be wrong). Another possible cause (not sure how strong it would be) is that a number of sunny days could warm up a large body of water, then over the course of a few cloudy days the water would slowly cool. Probably that effect would be rather small though. Digfarenough

Steak on a black eye

I have often seen on television (I know...never trust the damn thing, but I wanted to know) people holding streaks to a black eye for some kind of comfort or relief. Sometimes they are compltely frozen, and sometimes it is just a raw (although I assume chilled) steak. This perplexes me for a varitey of reasons.

1) While the steak might be cold, what about the meat juices and such that would come out from contact with your face if it was raw and the melting of the ice around the steak by your body heat? Isn't that dangerous and/or yucky and disgusting?

2) Is there anything actually IN the steak (chemicals or etc.) that help reduce the pain, swelling, or discomfort of a black eye? I figured maybe that's why they do it.

3) Why even use a steak in the first place? If you have a freezer with a steak in it, wouldn't you probably have ice or some other very cold foodstuff (a bag of frozen peas for example) that would work just as well as a frozen steak?

Thanks, --69.138.61.168 07:00, 26 July 2006 (UTC)

One advantage that comes to mind is the fact that cold steak (if it isn't frozen) is malleable; it can fit better on your eye better than peas can. --Kjoonlee 07:57, 26 July 2006 (UTC)

Not so, Kjoonlee. A bag of frozen peas will be quite malleable, as the peas only stick together (when they do) in small clumps. —Daniel (‽) 08:37, 26 July 2006 (UTC)

The steak thing comes from the 1930's madcap movies and 40's cartoons. At that time, it was probably the only cool thing from the icebox, and it was only 5 cents a pound! For any impact injury or strain (sprain), you can ice it with a gel pack. Always put a cloth inbetween, and only do it about 10 min at a time. --Zeizmic 12:26, 26 July 2006 (UTC)

E=MC²

Why is it that energy and mass are interchangeable? It does right? But why?

See E=mc² and General Relativity -Benbread 09:12, 26 July 2006 (UTC)

No need for general relativity. Special relativity will do nicely. --198.125.178.207 16:57, 26 July 2006 (UTC)

My college physics teacher explained it partially by dimensional analysis: Energy equals work equals force times distance equals mass times acceleration times distance, so the units of energy are (kilogram*meters^2)/(second^2). The units of mass are kilograms the units of velocity of light or anything else are (meters)/(second). So other than some proportionality constant due to the units used, it pretty much has to work out that way, and there was nothing surprising in the equation. It could not be, say E=MC, or E=MC cubed, or E=the square root of (MC) or the measurement dimensions would differ on each side of the equals sign.

When Uranium fuel is used in reactor, its mass decreases by about 1%, which multiplied by c squared gives the energy given off by the fission reaction. If an equivalent amount of energy were given off by burning coal, oil, or gas in a power plant, the mass of the fuel plus the combustion oxygen would decrease by the same number of kilograms. If a metal cube were simply heated up without any chemical or nuclear reaction, the weight of the metal would increase by an amount equivalent to the heat energy added divided by c squared. Both these weight changes would be too small to measure practically.Edison 20:49, 29 July 2006 (UTC)

About the main parts of an experiment.

what are the main parts of an experiment?

• Perhaps you want to see scientific method? —Mets501 (talk) 09:49, 26 July 2006 (UTC)

It also depends on what type of experiment you are trying to do. Iolakana|^T 12:37, 26 July 2006 (UTC)

I think you'll do better with the article experiment. --198.125.178.207 16:58, 26 July 2006 (UTC)

protists

the importance of protists to all other living things

This sounds a bit like a homework question, please do your own. You can start with protist and ecosystem. The protist kingdom is large and plays a variety of different roles in a variety of different ecosystems. Emmett5 15:04, 26 July 2006 (UTC)

The diference

I want to ask a simple question (maybe for you) but it still make me confuse What's the diference between Radio frequency and intermediate frequency?

Take a look at superheterodyne receiver. Basically, you tune a radio by mixing (multiplying) a local oscillator with the RF signal to bring it down to the IF (intermediate frequency). Then, the electronics that convert the signal from the IF to audio frequencies do not have to be tuned and are cheaper because they are not high frequency, high bandwidth components. —Bradley 16:01, 26 July 2006 (UTC)

Master/Slave for CD-ROM/CD-RW stuff

OK, so I've put all of my hardware into a new computer tower (with a new motherboard and CPU--yay!) but I forgot which settings on CD drives determine its master/slave position. One of the CD drives has its master/slave jumper look like this:

* I *
* I *

and the other looks like

* * I
* * I

(Where "*" means a pin and "I" means a plastic piece)

Which is which? The ikiroid (talk·desk·Advise me) 16:25, 26 July 2006 (UTC)

• Unfortunately, there's no real standard, and the jumper positions differ between different makes and models. Unless it's marked on the drive itself (it quite often is), look up the drive's model number on-line and find the instructions from the manufacturer's website. --Bob Mellish 16:36, 26 July 2006 (UTC)

And don't forget to check out our shiny new Computing Reference Desk. However, the reply above is exactly right. --LarryMac 16:45, 26 July 2006 (UTC)

Oh.....I didn't even see the new reference desk. Sorry about that. The ikiroid (talk·desk·Advise me) 17:30, 26 July 2006 (UTC)

Well, while there's no official standard, there's a de facto standard for CD drives (unlike HD drives, which tend to be all different). I just looked at an old CD drive I had, and the settings are: right jumper for master, middle jumper for slave, left jumper for cable select (so, your first one would be the slave and the second one the master). It's also always or almost always written on the drive itself (look carefully near the jumpers; you probably will find the text as a relief on the plastic there). --cesarb 17:41, 26 July 2006 (UTC)

OK, I checked the drives and you were right, Cesar. They're labeled (albeit barely). And I'm 86% sure that on the ribbon, the middle connector goes to the slave, right? And the end connector goes to the master? The ikiroid (talk·desk·Advise me) 17:56, 26 July 2006 (UTC)

The cable doesn't matter if you have the drives set to Master/Slave. The cable only matters if you set them to CableSelect. --Kainaw ^(talk) 18:00, 26 July 2006 (UTC)

In fact, it does matter; AFAIK, one of the things the master/slave setting selects is which drive has the termination. The termination should always be at both ends of the ribbon; so, you must put the master at the end of the ribbon, and the slave at the middle (if you have a single drive, it must always go at the end of the ribbon). --cesarb 22:18, 26 July 2006 (UTC)

A small note: after doing some searches to find out more about it, I have seen about the same number of people claiming IDE is terminated and claiming IDE is unterminated; if it's unterminated, the only requirement would be that both ends of the cable are used. I have even seen someone claiming it's terminated only on the faster UDMA modes (which would explain why some say it is and some say it isn't, and also makes sense). I have also seen people saying that it's important to plug the correct end of the cable to the motherboard (the blue one) on 80-wire cables (because the extra wires are grounded at only one of the plugs). So, to avoid any possible problems, it's better to be safe and plug the blue end to the motherboard, the black end to the master, and the middle gray connector to the slave. --cesarb 23:15, 26 July 2006 (UTC)

I have found on some cd drives that the master/slave/cable select lables are embossed into the casing on the top of the drive above the jumpers. These can be difficult to see if the drives are dusty. Hope this helps

Testosterone or DHT increases muscle size?

On the one hand, the Dihydrotestosterone article says: "DHT has been shown to be deactivated in skeletal muscle through the actions of 3-alpha hydroxysteroid dehydrogenase and therefore does not have a significant effect on muscle hypertrophy."

On the other hand, a scheme in "Medical Biochemistry" by J. Baynes and M.H. Dominczak says that DHT is responsible for mediating "anabolism, muscle mass". So, which is it that increases muscle size? Jack Daw 17:12, 26 July 2006 (UTC)

Endocrinology is pretty damn complicated. From my memory, DHT is a shorter-but-stronger-acting form of testosterone. That is, it has a great effect initially, but cells become less sensitive to it rapidly. Just because it does not mediate muscle hypertrophy does not mean that is is inactive in growing muscles, it may be implicated in myocyte recruitment (that is, if it doesnt make the muscle cells larger, it may make more of them). That said, there are many examples of paradoxical behavior in endocrine systems (steroid hormones, in particular). For example, the female sexual characteristics that are triggered on a whole body scale by estrogen, are sometimes locally mediated by DHT. It may be that under certain cicumstances and time-scales, DHT increases muscle mass, whereas under other conditions, it has a different effect. Tuckerekcut 15:22, 27 July 2006 (UTC)

odd water fowl seen on a trip to Tennessee

I have a picture of this wierd bird I saw on a river in Elizabethton, Tennessee, next to a covered bridge. I guess I cannot post it here. It was either a goose or duck. As big as a goose. White and black, with a red head. Very strange. I have never seen a bird like this. Does anyone know what it was? Thank you! Sue T.

Here is a duck with that coloring -- http://ohiodnr.com/wildlife/Images/diversity/Redheadlg.jpg, found on this Waterfowl Identification page. If you can post your picture at ImageShack or somewhere like that, you could then post a link here. --LarryMac 18:10, 26 July 2006 (UTC)

Muscovy Ducks are quite large for ducks, and would also fit.--Shantavira 18:25, 26 July 2006 (UTC)

about masturbation

hi all

is it good for health to have a regular masturbation practice......

Regular, yes. Obsessive, no. See the article. (we are, after all, an encyclopedia!) --LarryMac 19:21, 26 July 2006 (UTC)

Well, it's probably even healthier to have sex regularly, but life being what it is... --198.125.178.207 20:29, 26 July 2006 (UTC)

All considerations taken, I would have to say that masturbation is much healthier than sex, as a general rule.Tuckerekcut 15:13, 27 July 2006 (UTC)

Well, yes and no. You don't get much excercise masturbating, but on the other hand you don't get diseases either. I'd say it's a toss-up. Black Carrot 19:47, 27 July 2006 (UTC)

Of course it depends on what your masturbating with, stay clean. — The Mac Davis] ⌇☢ ญƛ. 20:16, 27 July 2006 (UTC)

oldest tv program

what is the date of the beginning of TV? programs? --207.42.222.108 19:58, 26 July 2006 (UTC)

Try starting with the article television. --Kainaw ^(talk) 20:02, 26 July 2006 (UTC)

The longest running TV show is, I believe, Meet the Press, which started airing in 1947. The longest running *syndicated* TV show is The Simpsons (syndicated means it is shown in rereuns. The news shows, for example, are never rerun). Raul654 20:02, 26 July 2006 (UTC)

The Daily Show is. Black Carrot 19:45, 27 July 2006 (UTC)

UV light through glass

I seem to remember having learned way back in high school that it's not possible to get a sunburn through glass, that the glass molecules are too close together to allow the right type of UV light to come through. My memory may be going or I just remember incorrectly, but nobody else has heard of this, or has heard the exact opposite. The Wikipedia entry on UV light says "Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths" and further that UVA light particularly "penetrates deeply and does not cause sunburn." Would I be correct in assuming that that means UVA will pass through, UVB and UVC will be blocked, so you can't be burned, but there can still be tissue damage and cancer development? Would the damage perhaps be worse than normal, since the body won't develop melanin, helping to block the rays out?

This figure (warning-it's a PDF) shows the absorbance of glass as a function of wavelength. (The type of glass isn't specified, but it's close enough for our purposes anyway.) As you can see, the glass absorbs very little light at wavelengths longer than 350 nm. This cutoff is smack in the middle of the UVA range (315 to 380 nm), so yes—a fair bit of UVA is still passing through the glass. For the shorter-wave UV, next to nothing will pass through unless you're using very bright UV illumination or very thin glass (A couple of millimeters of glass will reduce the UVB and UVC intensity by a factor of a thousand).

There's a good section on health effects in our article on ultraviolet. Briefly, all three types of ultraviolet light are energetic enough to damage skin proteins and cause wrinkles; the jury is still out, however, on whether or not UVA can cause DNA damage and skin cancer. TenOfAllTrades(talk) 22:54, 26 July 2006 (UTC)

I've done experimental work with deep UV lasers, and let me tell you it can be nauseatingly hard to get good optical elements that will work because ordinary glass is absolutely unusable. Incidentally, modern cars (at least in the US) are required to meet certain UV absorption standards for the glass they use so that people won't get burned driving long distances. I've been told many auto manufacturers actually greatly exceed the standards because it is easy to chooses glasses that very efficiently block UV. Dragons flight 23:18, 26 July 2006 (UTC)

Ooh cool, what materials do you have to use for UV optics? —Keenan Pepper 01:17, 27 July 2006 (UTC)

Speaking as a chemist, we use fused quartz in a variety of applications because it is extremely resistant to heat and most chemicals, and is transparent to UV down to about 170 nm. Sapphire is also used for some optical components (transparent down to about 250 nm) because of its high strength, hardness, and resistance to heat. TenOfAllTrades(talk) 02:35, 27 July 2006 (UTC)

Just curious, TenOfAllTrades, but are the sapphire ones really saphhire (like, blue...) or alumina?Tuckerekcut 15:10, 27 July 2006 (UTC)

Well, they're pure aluminum oxide in crystalline form, grown industrially in large ingots. The blue colour of natural sapphire (or ruby, which is mostly the same stuff) comes from trace metal impurities in the crystal; the optical grade stuff is colourless because it has a very low metal content. The industrial sapphire is like natural sapphire inasmuch as it's large, transparent, single crystals. For some applications, the sapphire is deliberately doped with metals to alter its optical properties; titanium:sapphire lasers, for instance, use ultrapure sapphire doped with a bit of titanium. For applications where colour isn't important, trace impurities are tolerated to a greater extent. I had to repair a high-pressure solvent pump that had little sapphire pistons; those ones were a pale greenish colour. TenOfAllTrades(talk) 16:03, 27 July 2006 (UTC)

Yeah, so ordinary glass absorbs most UVB and UVC radiation, but lets through UVA. This isn't a big deal when you are talking about blocking UV from sunlight because most UVA radiation is blocked by the Earth's atmosphere. In fact, glass blocks UV rays so well, that I recall needing to use special types of glass and plastic test tubes and petri dishes when working with bacteria in the lab which we planned on killing later with UV light. We had to pay a lot of extra money to make sure that the UV would penetrate the material with enough energy left over to kill the organisms inside. Indeed, I always have a little laugh when I am at the picture-framing store and the framer asks if I would like to purchase special glass to protect my pictures from UV light. Regular glass does quite nicely.Tuckerekcut 15:07, 27 July 2006 (UTC)

July 27

Dizzy.

I'm really dizzy. I was watching a medical show on t.v. and I started to feel a bit dizzy, after I put my head up. I figured it was all in my head at first, because I was watching a medical mysteries thing. When the show was over, I turned off the t.v. and sat up. I felt alot more dizzy and began reaching for the remote to see what was going on. I felt really scard for some reason, and I wanted a light back on. I started sweating, mostly from fear. I thought a man was coming at me, but I am guessing this was only because the show was focused on night terrors ect. I went up stairs, I was very distraught and scared. I told my parents, and they said to go lay down and get a drink. So I went back down stair with my water, and laid down on the couch. I felt good again, until I got back up to use the washroom. I could barely finish my urination before I began feeling dizzy again. In fact I had to sit down immideiately after leaving the washroom because I could barely stand. I sat in the corner for a bit until I deceded that maybe they would be able to help me on wikipedia. So I walked up stairs, it was a bit easier than last time. I went on, still a bit dizzy (I am still dizzy) and now I am asking. I lookd under causes of dizziness, but I have a hard time matching my symptoms with the other sypmtoms listed. I am 5'10 and 120 pounds. I am underwieght but Not Anorexic or bulimic. I do use the computer alot. I have no history of epilepsy or anything like that. A few years back I did have a twitch in my eye, and I had brain tests done. For breakfast I had an all bran bar and water. For a snack I had chips and water. For supper I has two mcdonalds cheeseburgers. I drank a few bottles of water throughout the day, and went for a bike ride. I had a few msquito bites (I'm not sure about west nile symptoms or how quickly they appear) and I was by a campfire. I just realized a good example for my dizziness. It feels kind of like I just had a few too many cigarettes, but less stomach sickness and more dizziness. PLease answer ASAP I don't want to sleep really untill I find out whast wrong. And while we're talking about sleep, I only got about 5 hours of it last night, which might be a cause aswell, I don't know.

Oh my. Well, first off, Wikipedia is not a doctor's office. Maybe you could find the reason in our article on dizziness, which lists several causes, but if it continues or worsens you may want to see a doctor. Hyenaste ^(tell) 04:03, 27 July 2006 (UTC)

That being said, if you're in the northern hemisphere, it can get hot in the summer, and at least for me the most common cause of dizziness is dehydration. Try drinking some more water. --18.239.6.57 04:23, 27 July 2006 (UTC)

Yeah. Apart from general principle, you should definitely ask a qualified doctor about dizziness. It's such a vague symptom, and so common, and caused by such a wide variety of things(including sitting up too fast and, as you say, five hours of sleep), that that alone isn't nearly enough for a diagnosis. If it was more specific, like a bumpy rash or discolored fingernails, we could at least give good odds on something. Black Carrot 04:29, 27 July 2006 (UTC)

You didn't sign your posting, so I can't see what time you wrote this. But if you're in Europe, you're in the middle of a heat wave. The most threatening thing about that is dehydration because thirst is a bad indicator for that, so people don't notice they don't drink enough. You say things improved after you drank some water. Drink some more. And drink at least a few litres per day. See if that helps. DirkvdM 09:33, 27 July 2006 (UTC)

The most common causes of dizziness in teenagers are anxiety, orthostatic hypothension, and hyperventilation, none of which is dangerous. However, there are many other more serious causes. If it does not happen again do not worry about it, but if it recurs see your doctor. Also, get some sleep, get some exercise, and eat less McD. alteripse 11:34, 27 July 2006 (UTC)

Thanks, it turned out to be an inner ear infection. I went to the hosptial the next day.

Ouch. I had an ear infection a little while ago (albeit not an inner ear infection) so I know how much that can hurt. Hopefully you got the treatment in time before the pain got really bad. The dizziness makes sense for an inner ear infection because that's where the balance organ is. The Equilibrioception article mentions it as one of the causes. DirkvdM 06:14, 28 July 2006 (UTC)

Ditto. I've had the opportunity to experience it twice, and it was pretty horrible both times. And that, of course, is exactly why we aren't allowed to diagnose anything - not one person suggested that. Black Carrot 05:01, 29 July 2006 (UTC)

Yeah, but we can still try to help. We're instant (especially important at night, as in this case), for a doctor you have to make an appointment. Drinking water might have helped and it could hardly have hurt. DirkvdM 06:49, 29 July 2006 (UTC)

Rifle Bullets and Speed of Sound

If a 7.62 x 51mm NATO round breaks the speed of sound when fired from a rifle, why doesn't it hit a target soundlessly?

I have seen metal plates hit with rifle bullets, of this particular caliber especially, and it still goes 'BING'. Shouldn't it hit the plate soundlessly and then be followed by the sound of it hitting the plate a few moments later?

I came up with this question after noticing that when a bullet like this is fired from a rifle, the echo of the report is actually quite a bit behind the bullet actually making an impact against something, depending on how far away the shooter is, sometimes it is a whole second or more. So why doesn't it do the same thing for a target? Thanks, --69.138.61.168 05:06, 27 July 2006 (UTC).

The sound of it hitting the plate is produced.... when it hits the plate. That sound then propagates outward at its normal speed. The report is produced when the cap of the bullet explodes, and does, as you say, lag a bit behind the bullet. Black Carrot 05:13, 27 July 2006 (UTC)

(edit conflict) It doesn't really have anything to do with breaking the sound barrier; it's just a matter of where the observer is standing with respect to the events occuring. When the shot is fired, both sound waves (slow) and light waves (fast) start traveling from the barrel to your eyes and ears. Same thing when the bullet hits the target. If you're standing near the target, the time separation between sound and light for the impact might be too small to detect, but if you're far away from the shooter, you might be able to detect the separation for the report. The shooter herself ought to be able to hear separation for the sound of the target impact, but not for the report. This should all hold true regardless of the speed of the bullet. --Allen 05:15, 27 July 2006 (UTC)

The bullet carries its own sonic boom with it. Just as a little tidbit of info. — The Mac Davis] ⌇☢ ญƛ. 15:34, 27 July 2006 (UTC)

Really? So, if you were to fire a bullet at a sheet of glass, but miss, would the glass still shatter? Black Carrot 19:42, 27 July 2006 (UTC)

Sonic booms don't automatically break windows. They shake them. If it's a big boom they shake them a lot, and that might break them. A rifle sonic boom is not that big, so I don't think it will shake the glass very much. 71.199.123.24 21:17, 27 July 2006 (UTC)

Depending on the round, it can be big enough to blow your eardrums if fired too close to your ears. --Kainaw ^(talk) 00:17, 28 July 2006 (UTC)

Just as a further consideration, even though the muzzle velocity is above the speed of sound, the bullet may be going quite a bit slower than that depending on how far away the plate is, air density, etc. Matt Deres 14:25, 28 July 2006 (UTC)

I've tended targets on an 800m range where the shooters were using supersonic rifle ammo. The report from the shot was quiet compared to the sonic boom (of course, the report was nearly a kilometer away, the sonic boom - as Mac Davis said - is carried with the bullet. The sonic boom came noticably before report. --Polysylabic Pseudonym 10:28, 4 August 2006 (UTC)

Protein in Synovial Fluid

Can anyone tell me why there is a high level of protein in the synovial fluid?*****************************************AmberChoate

I'm no biologist, but it seems obvious that since the purpose of the synovial fluid is lubrication, it has to be made of thick, slippery proteins. —Keenan Pepper 20:03, 27 July 2006 (UTC)

Regardig child Hemoglobin

My baby (1 year and 3 months old) is suffring from problem of less Hb.i am working in cement factory. he stay with me for three months before this he was weak but active .but when he stayed with me in the factory area. he was told that suffring from less Hb. Now doctor gave hin three months therepy.

0n july 1-2006 Hb-7Gram Tcl   6000
on july 10-2006 Hb-8gram tcl- 4200 
on july 27-2006Hb-9gram Tcl   8900

Please tall me how much should be the Hb of child What are the best medicine to increase Hb. Is there ant relation about the bonemero to this if yes tall all. what should be the diet (vegitarian) to give the child . how to increase the quanity of milk.

Pl send reply on <e-mail address removed>

Pankaj kumar

solan (h.p.)

These would be great questions to ask your baby's doctor. — Knowledge Seeker দ 06:50, 27 July 2006 (UTC)

A 15 month old baby should have a hgb of at least 11 g/dl. Anemia at that age in North America is most commonly caused by iron deficiency related to high cow milk intake. The treatment is less milk and more iron. I know of no vegetarian iron source high enough to quickly reverse iron deficiency if that is the problem, but there are inexpensive pharmaceutical iron supplements. There are many other possible causes of anemia in a 15 month old, and I do not know the relative probabilities in south Asia. If the cause is not iron deficiency, then extra iron will not fix it. Thalassemia is a common cause of anemia in which the CBC might suggest iron deficiency but it would not respond to treatment. The rest of the CBC and a reticulocyte count would distinguish excessive blood loss or destruction from most causes of reduced production of red blood cells by the bone marrow. You do not tell us what "therapy" was given. Ask your baby's doctor these questions. alteripse 11:29, 27 July 2006 (UTC)

Dark green leafy vegetables like spinach, kale, and broccoli are good sources of iron, but it may be difficult to get a young baby to eat those things. The most common way to add iron to a baby's diet is with iron-fortified milk or cereals. --18.239.6.57 16:13, 27 July 2006 (UTC)

You need your doctor to give you a better diagnosis of your baby's anemia. Since you work in a cement factory, and the baby spends time there, it might be appropriate to wonder if he's eating clay, a behavior (pica) that can cause iron-deficiency. Your doctor should be able to tell you from the baby's blood test if it seems to be an iron-deficiency anemia or not. The hemoglobin seems to be getting better on therapy, but you don't say what that therapy is. - Nunh-huh 18:32, 27 July 2006 (UTC)

That isn't correct - the clay-eating pica is a symptom of iron-deficiency, not the cause. The most common cause of iron-deficiency is...deficiency of iron, as in not enough iron in the diet. --198.125.178.207 20:27, 27 July 2006 (UTC)

You're mistaken. Current literature is divided over whether pica causes iron deficiency or iron deficiency causes pica; it's certainly something to consider when a child spends his day surrounded by clay. - Nunh-huh 21:16, 27 July 2006 (UTC) (And, of course, the most common cause of iron-deficiency anemia is menstruation.) - Nunh-huh 21:18, 27 July 2006 (UTC)

If this is true, and you can find some citations to support it, please change the article on geophagy or pica to reflect the controversy. --198.125.178.207 21:38, 27 July 2006 (UTC)

Parry SD, Perkins AC, Hawkey CJ, "A case of pica and iron deficiency anaemia in Nottingham", Int J Clin Pract. 1998 Jul-Aug;52(5):354-5. "Current literature leaves uncertain whether pica causes iron deficiency via its proposed effect on iron absorption or, conversely, whether iron deficiency causes pica." - Nunh-huh 22:01, 27 July 2006 (UTC)

Pharmaceutical color coating

I was trying to understand the pharma color coating industry - what are the technologies that are involved and how is the whole process run...I am looking for color coating for tablets as well as caplets

Thanks Vikram

Synasthesia

Synasthesia is the condition by which different senses get 'confused', and (for example) sounds can appear as pictures. My question is: If someone experiences sounds as pictures, do they also experience the reverse? Would seeing what is normally the response to a high-pitched beep induce hearing a high-pitched beep? Or is it strictly a one-way phenomenon?

Thanks. —Daniel (‽) 13:15, 27 July 2006 (UTC)

Our article on Synaesthesia may be of some help. Note the spelling, also; it can be spelled synaesthesia, or synesthesia. Tuckerekcut 14:49, 27 July 2006 (UTC)

Synaesthesia is one way, I believe. It's also usually not as general as you describe. The most common form (as far as I'm aware) occurs when specific letters of the alphabet (and sometimes numbers, mathematical symbols for mathematicians, etc) are associated with specific colors such that if you present the person with an A, they will get the sensation of seeing, say, a light brown. If many years later you present A again, they will sense the same color. Multiple symbols may share the same or similar colors, but I don't believe it is usually the case that if you show them a particular color, the symbols associated with it will come to mind. In general there are a lot of different kinds of synaesthesia, so there may be a few rare individuals that would show the phenemona you describe, but the type I'm most familiar with (which isn't terribly familiar) is as I described. Digfarenough 22:20, 27 July 2006 (UTC)

I can say with relative confidence that synesthesia is indeed a more general shift from one sense to the other, but is equisitely variable from person to person. The accounts given in the article cited above do reference the stories of individuals who are effected in the way Digfarenough described, but I believe that this in an instance where wikipedia's article is not as comprehensive as it could be. It is notable that in many of the instances given for that article, the synesthesia is conducive to seeing various types of creative pursuits in new ways (an arguably beneficial set of cases). I am aware of some accounts (related to me personally) where individuals under the influence of certain chemicals could "hear" certain kinds of light, for example one individual claimed that flourescent lights sounded like buzzing insects and incandescent bulbs hummed pleasantly.Tuckerekcut 04:15, 28 July 2006 (UTC)

Thanks, all. Very interesting. —Daniel (‽) 20:27, 28 July 2006 (UTC)

Laurus nobilis, fertilization of

We have a potted bay tree, very young and small.

I want to know whether to use "all-purpose" fertilizer for it, or would "acid" fertilizer (that we use for potted citrus trees) be better?

(email removed)

(MaryAnn Salo)

We don't have any information on this in our Bay Laurel article, however a google search for "laurus nobilis" turns up a number of links that mention fertilization techniques but don't mention the use of citrus fertilizer. --Robert Merkel 17:57, 27 July 2006 (UTC)

Pauli's principle Pauli's exclusion principle

In a book, I found out that there is a difference between Pauli's principle is a little different from Pauli's exclusion principle. Is it true? I know in the article of Pauli, It is mentioned as the same thing. But please get it confirmed. I will be grateful to anyone who helps me.

Well, what does the book claim as the difference? Melchoir 16:20, 27 July 2006 (UTC)

I'm not familiar with a Pauli's principle. — The Mac Davis] ญƛ. 20:12, 27 July 2006 (UTC)

• Wikipedia has articles on Pauli effect and Pauli exclusion principle. --JWSchmidt 02:17, 28 July 2006 (UTC)

The Pauli effect was when Pauli was in town, experiments tended to go wrong! The Pauli Exclusion Principle is a quantum-mechanical effect. It states that no 2 electrons could occupy the same set of quantum numbers in a quantum orbital. Since electrons are identicle, the only difference would be their spin.

Actually, this not only applies to electron but to fermions, particles with half-integer spins. And the occupation not only applies to atomic orbital but to all quantum states.

science

What is the scientific mechanism that causes you to go blind when you masturbate?-Titanicalastic 15:43, 27 July 2006 (UTC)

There is no mechanism, it's a myth. Dragons flight 15:46, 27 July 2006 (UTC)

Alright so the mecahnism is supernatural not scientific, still, what causes it to happen?-Titanicalastic 15:57, 27 July 2006 (UTC)

God sees you, gets mad, and pokes your eyes out. --18.239.6.57 16:15, 27 July 2006 (UTC)

May we assume you haven't gotten around to trying this yourself? Black Carrot 19:40, 27 July 2006 (UTC)

Dude, you can masterbate all you want. Its fun. — The Mac Davis] ญƛ. 20:11, 27 July 2006 (UTC)

Come on, watch that spelling. Masturbating is so much more fun than masterbating. For one, it's spelled right. - Mgm|^(talk) 22:30, 28 July 2006 (UTC)

A sub-question. Ages ago, some people on these pages asked questions about having trouble coming with a woman, and the answer some people gave was that they had experienced it themselves due to excessive masturbation with too firm a grip. Is this a real thing, and are there studies/cites? If so, shouldn't teachers mention it? Just a wonder. Skittle 22:18, 27 July 2006 (UTC)

• Try autosexuality --JWSchmidt 02:13, 28 July 2006 (UTC)

You ask a question on the science ref desk and then exclude scientific explanations? DirkvdM 12:22, 28 July 2006 (UTC)

Ironically, if Oedipus had masturbated instead of boinking his mom, it might have prevented him from blinding himself. StuRat 19:25, 28 July 2006 (UTC)

Fictional, anecdotal, yet persuasive. Black Carrot 21:52, 28 July 2006 (UTC)

see http://en.wikipedia.org/w/index.php?title=Traumatic_masturbatory_syndrome&oldid=38061888

Cashew nuts healthy?

Are cashew nuts healthy? The article doesn't say. Thanks, Jack Daw 17:46, 27 July 2006 (UTC)

Well, they're high-caloric, so it's certainly not a good idea to eat too many of them; you'll get fat. Beyond that I don't know. Note that Wikipedia does not give medical advice, so I'm not too upset that the article doesn't say. --Trovatore 17:56, 27 July 2006 (UTC)

A quick Google search reveals some good information. Check out this site, for example. Maybe you'd be willing to add some of the relevant data to the cashew page? -- Scientizzle 18:32, 27 July 2006 (UTC)

Given that most naturally occurring food that has been eaten for thousands of years is perfectly healthy, I wouldn't expect the article to mention health, unless there were specific concerns about health. The article says it's a food, and food by definition is good for you, unless of course you're allergic to nuts.--Shantavira 18:35, 27 July 2006 (UTC)

see also Urushiol --GangofOne 19:46, 27 July 2006 (UTC)

Nothing is healthy or unhealthy, it is the dosage that is healthy or unhealthy. If healthy means edible, than cashews are edible. If you are looking for a low-oil food, than cashews are not a good choice. — The Mac Davis] ⌇☢ ญƛ. 20:05, 27 July 2006 (UTC)

You say nothing is healthy or unhealthy, and that only dosages are healthy or unhealthy. Well, it depends to what you are referring. As a blanket statement, it is patently false. There are not only things one can consume on earth that are unhealthy, but downright deadly - poisonous - that one would only know was unhealthy due to knowledge from the past experience of others. In addition, you mention nothing about the quality of a product (due to plant or animal rearing), as that can and almost always will affect said quality. - Andrew Taylor; 19:10, 06 March 2007 (PST)

There is a belief in my community that cashew nuts are healthy but the seed coat is not (it is supposed to be harmful, as is supposed to be the case with some other seeds too). See the section Sumac Family (Anacardiaceae) in http://waynesword.palomar.edu/ecoph1.htm. The article Urushiol may help. --Wikicheng 04:35, 28 July 2006 (UTC)

I once experienced that last bit when I ate a raw cashew nut. It hurt my mouth so much that I was really worried, but it doesn't seem to be a serious health hazzard. As for the fat, yeah too much of that is unhealthy, but that's a silly remark because too much of anything is unhealty. That's why it's called 'too much'. :) In the US there is a real anti-fat craze, which drove me nuts when I was there because I like fatty food. It's just a matter of balancing it with the amount of energy you burn and the other sources of energy like sugar, which food in the US seems to be full of, which I also hated. The only country that's worse for food is the Philippines, where you can only get hamburgers.

Oh, and nuts in general are healthy. DirkvdM 12:29, 28 July 2006 (UTC)

You must have been in the US a long time ago, the low fat fad was replaced by a low carb trend, specifically the Atkins diet. This craze died off after the fat author of that book dropped dead. I believe in eating healthy vegetable fats and limiting unhealthy animal fats (except for fish) and avoiding trans-fats completely. Hopefully this craze will catch on. But then again, I would likely have to pay $10 per avocado if it did. StuRat 19:11, 28 July 2006 (UTC)

I was in the US in the mid nineties, but the low-fat thing was so pervasive that I thought it was more permanent. Maybe you're talking about a relative change. Low-fat food may still be more popular than in Europe, but that's just guessing. DirkvdM 07:09, 29 July 2006 (UTC)

Any question about whether something is healthy brings up the question "as compared to what ?". As a primary source of protein and fats, most nuts, cashews included, are probably healthier than many other sources of protein and fat, such as meat and poultry, but probably not as healthy as fish (fish without mercury, that is), tofu, beans (for protein), or avocado (for fats). If compared to other nuts, then cashews are somewhere in the middle, with walnuts being perhaps the healthiest due to their high omega 3 fatty acids and macadamia nuts being perhaps the worst for their even higher total fat content. If compared with junk food, like potato chips, then cashews are a definite improvement. One thing to watch out for, though, is that nuts are frequently salted excessively, which makes an otherwise OK treat quite unhealthy, especially if you have to down a soda to compensate for all that salt. StuRat 18:58, 28 July 2006 (UTC)

A question almost everyone fails to ask is "Why is fish somehow good (when not contaminated with mercury) but land animal meats somehow so bad? Aren't they both natural meats?" The simple fact lies much in your reference to Omega 3 fatty acids in asserting walnuts are likely the healthiest of nuts. Omega 3 presence in meats is entirely subject to husbandry of the animals. The fish you refer to as being healthy is wild fish. All farmed fish has been shown to be just as bad as the ever-vilified beef. When put into an unnatural situation and fed an unnatural diet, the balance of omega 3 to omega 6 shifts drastically in the direction of the latter. Cows and chickens are not designed to eat grain. How would they in a natural setting? They are meant to eat grass, and in the case of chickens, perhaps some bugs as well. It has been shown that animals with such a diet (often called "grass-fed") have equivalent if not near equivalent levels of omega 3 as wild fish. -- Andrew Taylor; 19:10, 06 March 2007 (PST)

Cashews and pistachios, as well as poison ivy, poisonoak, poisonwood, and sumac are in the family anacardiaceae. Many people have extreme allergic reactions to many mambers of that plant family. [[] 00:00, 31 July 2006 (UTC)protogeek

nephrology laboratory terminology

how would you write out 381 mg per gram of creatinine in a scientific formulation?

First of all, we would need to know 381mg of what per gram of creatinine? Rockpocket 20:22, 27 July 2006 (UTC)

Biological exposure indices are often given in terms of "mg/g creatinine". I'm not quite sure what you mean by "scientific formulation"; in words, it's "381 milligrams per gram of creatinine"; abbreviated, it's "381 mg/g of creatinine". In a nephrology lab, you're probably measuring albumin to creatinine ratio as a measure of nephropathy? So "381 mg albumin per gram of creatinine".... or "an albumin/creatinine ratio of 0.381". - Nunh-huh 21:13, 27 July 2006 (UTC)

prada willy syndrome

Can you direct me to any info on this?? I can't find anything on Google.°

David

It's a joke - at least according to this blog. It says "Prada Willy Syndrome: A disease where women are not interested in a man's willy unless he can keep her in Prada." --198.125.178.207 20:43, 27 July 2006 (UTC)

See Prader-Willi syndrome Richard Taylor 21:06, 27 July 2006 (UTC)

LOL - nice work Richard - is that what you were looking for David? --198.125.178.207 21:08, 27 July 2006 (UTC)

Is it any coincidence that there was a documentary on Channel 4 about this one hour ago!? Iolakana|^T 21:47, 27 July 2006 (UTC)

LOL, spelling is so important. Sorry but I can't help point out the corollary: what we might call vagina-hamburger sydrome.--Shantavira 06:59, 28 July 2006 (UTC)

• This just happened to be on Dr. Phil one or two days ago in the Netherlands. Can't be a coincidence. - Mgm|^(talk) 22:28, 28 July 2006 (UTC)

Sound and Wind

This may seem like a silly question to you, but to me it's a pretty darn good one. Anyways, I was outside recently during a thunderstorm (putting away things that shouldn't get wet) when I saw a flash of lightning. Suddenly, the wind picked up and then thunder came. A few seconds after the thunder ended, the wind died down again. This leads me to my question: can sound waves (such as the ones caused by lightning/thunder) increase wind speed? Thanks --71.117.41.30 20:41, 27 July 2006 (UTC)

I don't know, but I tend to doubt it. It doesn't seem like a lightning strike should kick up wind in any single direction, and it wouldn't be able to blow purely outward either, because the air has to come from somewhere. That leaves the possibility of forming a convection cell, which I guess is plausible since the lightning does dump heat into the air. But enough heat to form a cell a few miles wide?

Either way, I wouldn't point my finger at the sound waves, since a wave alone doesn't displace much material if any. And if the wind picked up before the thunder reached you, then the advancing thunder would have had to launch a supersonic wind, and that just causes all manner of logical problems. Melchoir 21:01, 27 July 2006 (UTC)

No - I'm pretty sure that was just a coincidence. The thunder is a sound wave created by the violent sudden heating of the air near the lighning bolt. If you look over that article on sound waves, you should see that sound waves are propagating pressure variations, so when you hear the thunder, in a loose sense, that is the "wind" from the lightning - any other wind is just a coincidence. --198.125.178.207 21:04, 27 July 2006 (UTC)

Wind is a permanent displacement of air. A flash of lightning also displaces air, but it does that for a very short period. After that, the driving force disappears and leaves a vacuum where the air first was, so it moves back again. This causes a wave with a very short wavelength, which is called sound and in this case thunder. DirkvdM 12:35, 28 July 2006 (UTC)

Here's some speculation. Thunderstorms are powered by the fall of electrically charged raindrops, and this makes the raindrops fall more slowly. (They slow down because they are charged negative, and are being attracted by a region of positive charge above.) But immediately after a lightning flash, the large region of positive charge within the storm cloud is lessened. Until it builds up again, the raindrops will fall more rapidly. And finally: raindrops drag a region of air along with them as they fall, so as the rain speeds up after a lightning flash, the wind should pick up too. --Wjbeaty 17:23, 28 July 2006 (UTC)

On a variation of the above theory, the sound waves may force water particle in the air together to form drops large enough to fall, thus "dragging some air along with them". This would create a downdraft which would eventually spread out as wind. I doubt if this would be a very noticeable effect, compared with wind from other sources, however. StuRat 18:44, 28 July 2006 (UTC)

The sound wave is like a water wave, the particles in the air's displacement is theoretically zero. In a water wave, water molecules are moved up, then down, by energy, because a wave is just moving energy in a medium. Ideally, everything is put back where it was. A concussion caused by say, a nuclear bomb, will move things, but a sound wave is really more like a boost mode for a short time, then the particles move back to where they were. Ever listen to loud music? If you put your hand on top of a woofer you can feel the air being pushed out, and back in again, because the speaker, if you imagine your headphones for instance, the membranes, no matter how far they move and push air out, they always return to their original position and suck that amount of air back in. — The Mac Davis] ญƛ. 18:10, 28 July 2006 (UTC)

A concussion caused by a nuclear bomb would probably be pretty severe. :) DirkvdM 07:14, 29 July 2006 (UTC)

Stiches and Nosebleeds

what is the best way to stop stitches and nosebleeds? thanks --86.130.255.231 20:45, 27 July 2006 (UTC)

Not sure why you would need to stop a stitch, but here are some nosebleed treatments. Hyenaste ^(tell) 20:51, 27 July 2006 (UTC)

as in a stitch that u get after running for a long time --86.130.255.231 21:11, 27 July 2006 (UTC)

There is a surprisingly comprehensive article on the side stitch, which gives some possible treatments. Also, a more general article on cramps could be of use. --198.125.178.207 21:31, 27 July 2006 (UTC)

My sports teacher said the best cure was to keep on running. Not sure if he was a sadist. I do vaguely recall it helped, though. DirkvdM 12:38, 28 July 2006 (UTC)

lol, that's the "Just ignore it" treatment. Eventually it would stop anyway, and it may have provided the illusion that continiously running would fix it. — The Mac Davis] ญƛ. 18:11, 28 July 2006 (UTC)

As for stopping nosebleeds, roll up some tissue and put it up the nostril in question to absorb dripping blood until it scabs over. To avoid noseblleds in the future, keep the nostrils moist with a spray bottle or vaporizer. This should allow you to blow your nose instead of picking it. Also note that frequent nosebleeds can be signs of more serious health problems, like high blood pressure. StuRat 18:38, 28 July 2006 (UTC)

Taking the small sample of my family (5), we all had a tendency to nosebleeds at about the age of 14. Those who used Sturat's technique continue to have them into their 20s, those who applied outside pressure and cold until it stop ceased having them in a year or two. The GP was very cross when told the technique the younger brother was using (Sturat's) as it seemed to stretch stuff in his nose and increase his tendency. Just a head's up. But it is a very small sample. Skittle 18:04, 29 July 2006 (UTC)

For stitches, a preventative method is too breathe in a fixed rhythm (ie in in out out). If you concentrate on it you rarely get them. —Daniel (‽) 20:23, 28 July 2006 (UTC)

billion

how many zeros in a trillion

In ordinary arithmetic the answer is undefined, but there are other possibilities. See division by zero. --Trovatore 21:11, 27 July 2006 (UTC)

I think the question referred to the number of occurrences of the numeral zero in the base ten representation of the number one trillion. The answer is...found in the article names of large numbers. The answer actuallly depends on the culture- in the US, it's 12 zeros. In the UK, it's 18 zeros. --198.125.178.207 21:22, 27 July 2006 (UTC)

Haha, great answer, Trovatore! —Keenan Pepper 01:41, 28 July 2006 (UTC)

It's abit more complicated than that. The large numbers article says the English used to use trillion for the 18 zeroes, but have started to adopt the American system. I had wondered before about the logic of the systems used in English and in Dutch (and other languages). The large number name sequence (and the SI prefix sequence) works with powers of 1000. So it would make sense to use the word 'one' for thousand (to the power one), 'two' for thousand to the power two, etc. In stead billion (two) is used for 1.000 to the power three in English and thousand to the power four in Dutch. But now I see in the article Long and short scales that the Dutch system uses powers of one million. So billion means million to the power two and trillion means million to the power three. Odd that I hadn't noticed that before. The powers of thosuand in between are designated with the ending ard (so million - millard - trillion - trillard, etc). But in English it's a bit more complicated. There powers of thosand are used (which seems better), but you have to add one every time (which is not good). So trillion means thosand to the power three plus one.

I hereby propose a new system, based on the word thousand. bisand is then 1000², trisand is 1000³, quadrisand is 1000⁴, etc. Only thou is no word for one, but I don't want to stirr things up too much. :)

Then again, it can be simpler still. Why not simply use 'Kilo' for thousand, 'Mega' for million, etc. That would unify the two system (numbers and prefixes). DirkvdM 17:10, 28 July 2006 (UTC)

That brings up an old question of mine, why isn't there a metric system for time ? While admittedly the number of days in a year won't be an even multiple of 10 until we can strap some rockets on the Earth to change it's rotation and or revolution rates, there's no reason why subdivisions of a day or multiple years can't use metric prefixes. I guess we've just used the current silly system for so many kiloyears we just refuse to spend even a milliday considering alternatives. :-) StuRat 18:31, 28 July 2006 (UTC)

We do use kyr, Myr, Gyr. On the other end, ms, μs, ns, are also fine. It is only the junk in between that isn't very metric. Dragons flight 18:40, 28 July 2006 (UTC)

See Decimal time and Metric time. --Serie 18:46, 28 July 2006 (UTC)

I love how some guy's random question evolved into the reinvention of numbering M@$+@ Ju ~ ♠ 00:00, 29 July 2006 (UTC)

I've proposed some solutions to that too, on my user page: User:DirkvdM#Time. I seem to have an answer to everything. :) DirkvdM 07:26, 29 July 2006 (UTC)

We seem to be in total agreement on this issue. This is evidence that I apparently must now be clinically insane, as well. :-) StuRat 07:53, 29 July 2006 (UTC)

Join the club. It's a very small club. You're number two. I'm no longer unique! DirkvdM 19:06, 29 July 2006 (UTC)

UV lightbulb vs. UV light bulb

I am a technical editor and I was corrected by a scientist when I tried using "UV lightbulb" instead of "UV light bulb". Since "lightbulb" by itself is a single word, why is UV light bulb different? Convention?

Thanks for the help.

Lorin Fischer

I think "light bulb" is a more common usage for all types, UV or otherwise. It seems that "lightbulb" is acceptable. "light bulb" always seems to be the primary punctuation, for instance in our wikipedia article on Light bulb, and at princeton's online lexical tool. Could be wrong, though --198.125.178.207 21:28, 27 July 2006 (UTC)

It might also be that UV specifically needs to modify the word "light" in his/her mind (it is not a lightbulb which emits UV, it is a bulb which emits UV light). But I don't know, it sounds like a pretty pedantic distinction to me. --Fastfission 01:31, 28 July 2006 (UTC)

As has been mentioned, "light bulb" is more common that "lightbulb" (see this highly unscientific googlefight) but unless there's a good reason it's really just a matter of the publisher's style - for example, The Guardian's styleguide[6] calls for the use of "lightbulb". -- AJR | Talk 12:05, 28 July 2006 (UTC)

I would think that a lightbulb would be the incandescent lightbulb, where as light bulb would mean that light is describing the bulb. "Light" as in weight/mass, value (shade), or if it was literally made of photons. Therefore, lightbulb. — The Mac Davis] ญƛ. 18:13, 28 July 2006 (UTC)

Note that while questions about how light bulbs work belong here, grammatical questions about the usage of the word belong on the Language Ref Desk. StuRat 18:22, 28 July 2006 (UTC)

July 28

Politness in the name of vaingloriousness has no place on a Wikipedia discussion page, imho. (Pardon the puns, I couldn't help it).

Male/Male & Female/Female only fertilization?

I remember reading an article, I forget where, it was either Time, Popular Science, the newspaper, I forget, but the article said that scientists said it was theoretically possible to, say two gay men wanted a child, or a lesbian couple, that by taking dna from one of the men and stripping out an egg or whatever and inserting the genetic material, and doing the same with a womean (but an egg instead of sperm obviously and pulling a few genetic strings and flipping a few DNA swtiches there, that it would be possible for say, one part of the lesbian couple to inseminate her partner with sperm encoded with her DNA, and the two gay men, could have a surrogate mother who would carry a child whose DNA was comprised of the both of their DNA. Am I making sense? The article did not imply or say the technology was available now or even absolutely possible. It only said it had a potential. If someone knows anything about this, I've been looking everywhere and I cannot find the article, and I do not know the correct way to word such a concep so that I could search for it with a greater accuracy.

Perhaps this? I just searched google news for "homosexual fertility". Digfarenough 13:05, 28 July 2006 (UTC)

That only mentions the possibility briefly. But I see a problem. A female/female dna couple would produce a female (two x chromosomes). But a male/male couple would produce two y chromosomes and I don't think that gender exists. And I didn't sleep during biology classes because those were the among the very few I found interresting at school. DirkvdM 17:27, 28 July 2006 (UTC)

Don't forget that males being XY can produce women (XX) and normal men (XY). Whereas lesbian couples would only produce females. -Pascal

Er, actually, I think you're both a bit mistaken. I don't believe YY is compatible with embryo formation; the syndrome to which you're referring is 47,XYY. But as Pascal points out, since (most) men have the karyotype XY, they produce both X- and Y-carrying sperm. If one were to combine them randomly, I would expect 25% to be female, (Xs from both parents), 50% to be male (X from one, Y from the other), and 25% not to form (YY). — Knowledge Seeker দ 17:46, 28 July 2006 (UTC)

I wouldn't assume that the chromosomes are randomly combined, but rather selected individually, which means two males could choose either a son or daughter and would avoid the YY combo. StuRat

First off, Males are XY, so two fused sperm (or whatever) would have a liklihood of 25% XX, 50% XY & 25% YY. YY disomies are highly unlikely to survive--the only cases of living humans with YY that I've found on PubMed have translocated large amounts of X chromosomal material on the normally miniscule and gene-poor Y chromosomes (there are several vital genes on the X chromosome). XYY males certainly exist, though. -- Scientizzle 18:04, 28 July 2006 (UTC)

Damn, I first make a very stupid claim and then even draw an incorrect conclusion from that. DirkvdM 07:33, 29 July 2006 (UTC)

Another problem that researchers must overcome in fusing gametes from the same sex is chromosomal imprinting. Natural developmental processes depend on controlled gene expression in the zygote, much of which is regulated by inherited gene silencing (often via methylation) on the maternal or paternal chromosomes. -- Scientizzle 18:04, 28 July 2006 (UTC)

Note that the offspring of the two males would contain the RNA from the egg donor in their mitochondria and that two females could have a son with a single Y chromosome taken from a sperm donor. This would only be one out of 46 chromosomes, so the child would still be almost 98% genetically their son. StuRat 18:14, 28 July 2006 (UTC)

How many people can parent one child? Could one also combine the brains of one person, the musical talent of another, the looks of a third, etc? DirkvdM 07:33, 29 July 2006 (UTC)

The intelligence of George Bush, the musical talent of Roseanne Arnold (specifically, her singing of the US national anthem), and her looks, as well ? StuRat 08:10, 29 July 2006 (UTC)

One can remain otimistic, but the human oocyte would be rather a problem. At fertilisation, it is not a gamete, it is a haploid cell arrested during the second meiosis - a long and poorly understood path from when it first differentiated in the fetus. No such entity as human female "gamete" exists (unless that is what one would call a 23X sperm?). It completes meiosis and becomes haploid only after a sperm penetrates it. At what stage could one introduce foreign DNA and expect the system to still function? Would male chromosomes be capable of maintaining the arrested meiosis stage? The problems are formidable; haploid little tadpoles are simple by comparison. I sometimes think men went out hunting and fighting because their contribution to the survival of the human gene was simpler to make in quantity, and that the the psycho/phenotype lines that did not protect the finite number of these very special reproductive cells that the female carried died out from lack of oocytes, not of sperm. Selfish genes make some sense. --Seejyb 23:20, 29 July 2006 (UTC)

The article which deals with this is parthenogenesis. I'm a little surprised no-one's mentioned this already. Dysprosia 11:55, 3 August 2006 (UTC)

rotation speed of the universe?

I have been wondering the possible rotation of the universe for quite some time. The subject haven't been discussed in any literature I've come across with, altho it seems like quite non-trivial and possibly interesting.

I guess it would be notoriosly difficult - if not outright impossible - to carry out such measurements. There's no reference points, obviously - d'uh! Without reference, it's the same as standing in a closed box. We can't distinguish movement from being "stationary", nor can we distinguish gravity from acceleration.

Based on the red shift and studies on other subjects, we have an estimate on the expansion speed of the universe. However, not knowing the mass of the universe, we can't tell what kind of circular orbital speeds we should expect at any distance from the centre. If the universe is expanding, however, we can be sure that the universe is not on a circular - but perhaps on an elliptic orbit around itself at the moment.

What might matter more, is the beginning of the "orbit". If a object is throwed away from a surface of a gravitational body, it will either experience an orbit that intersects with the body, or an escape orbit. If all the parts of the universe were on such an colliding orbit, eventual collapse would be imminent. However, artificial satellites sent from the surface of the earth are able to maintain (near) circular orbits, not intersecting the surface of the planet. This is possible because the payload and the fuel are accelerated in opposite directions after leaving the surface of the earth.

Likewise, universe might be on a non-self-intersecting orbit around itself, non-collapsing, yet not infinitely expanding - if there is significant difference in orbital angular speed in different parts of the universe. Now I'm not saying anything on whether or not such different orbits would or would not intersect. However, the energy for making that difference would have come from somewhere. I'm not saying that it has, just not ruling out that it couldn't have. Total angular momentum of the universe must have been preserved since the big bang, although differences in part of it could have emerged. Anyways, I'm going too far from the real question..

What is the current status on the study of this subject? Is the universe rotating, non-rotating, or is it an open question, or is either possibility just "assumed" out of convenience? Can we only make an equation that show the dependence of expansion speed on the angular speed and the mass of the universe, or is there base for the estimation of some single parameters?

If true, this theory would put a whole new spin on the universe. :-) StuRat 04:12, 31 July 2006 (UTC)

Uh, I guess those were questions, rather than a question. Anyways, as usually, I'd just love to hear your answers (and discussion). Thank you. 193.166.173.23 12:32, 28 July 2006 (UTC) Oh, it's as if my session timed out while I wrote down this minor question, or I was never logged in. Santtus 12:34, 28 July 2006 (UTC)

Oh, and I have to add to the story before letting anyone answer. If the estimate on the mass of the universe is based on assumption of non-rotation, obviously the universe would have a larger mass should it actually be rotating, in order to give the same appearance of phenomena for us poor humans, who are doomed to wander in here without any outside physical references whatsoever. *sigh* Santtus 12:41, 28 July 2006 (UTC)

There was a recent article in New Scientist relating to the universe rotating. The online version (which you have to pay for) is here [7]. JMiall 13:04, 28 July 2006 (UTC)

Blah, I subscribed to the magazine, but apparently I'd have to wait for the first issue to be delivered and use a printed code in the postal delivery to enable my online content. So you nice folks at Wikipedia have still a good 3-4 weeks of time to discuss this before I recieve my "spoilers" from the postal service ;) Eh, this might be of interest to a wider audience than those willing to subscribe to a premium service.. Santtus 14:13, 28 July 2006 (UTC)

I would have thought the question was meaningless (considering no point of reference outside the universe), so I await sight of the New Scientist article with interest.--Shantavira 14:47, 28 July 2006 (UTC)

It would be meaningful, even though no outside reference could be established. Given the lack of other meaningful explanations, the disparity between calculated mass and the observed gravity could be properly attributed to non-zero rotation of the measured body. Santtus 15:37, 28 July 2006 (UTC)

Rotational speed can be measured. Rotation imparts a centrifugal force on the object being rotated. This force is greater the faster the rotation and can be measured. So align such an object with an object on both sides of the universe and measure how fast it rotates. Thus the rotational speed of the object can be determined, and how fast it is moving closer or futher away can also be measured by red shift. Thus the speed and direction of the object can be determined.

Yeah, why not joggle with the universe while we're at it. It would just be much more convenient not to extend a measurement device for such a great distance. So obviously we'll have to contend with earth-bound measurements.. or anyways, measurements on distances insignificant compared to that of the diameter of the observable universe. The problem is that we have no solid medium in the universe where we would attach those measurement devices into ;P Santtus 15:32, 28 July 2006 (UTC)

Basically, you are saying that outward momentum from a central point is due to centrifugal force and therefore evidence of rotation. Right?? If something like a big bang sent everything outward in a straight line with no spinning, you would still have outward momentum. --Kainaw ^(talk) 15:30, 28 July 2006 (UTC)

Obviously he would have the universe-long measurement device free-floating in universe, not "attached" to anything like planets that would be moving fast away from the centre ;) Yes it would take quite a bit time to set up such a device, and even more so to get any readings from the device. Maybe it didn't even have to be very long. Still, I believe we're gonna get results faster by using what we have on earth and in vicinity. Santtus 15:43, 28 July 2006 (UTC)

If you ment that, I dont think that expanding is by itself any indication of rotation. Santtus 15:46, 28 July 2006 (UTC)

I'm not entirely sure what you are getting at, but if the basic issue is: "Does the total angular momentum of the observable universe = 0?", then that is at least an approachable question. One obvious observation is that any large scale rotation would give rise to anisotropy in the universe, with a natural direction defined by the axis of rotation, just as the equator and poles of the Earth move differently with respect to the Earth's rotation. Such anisotropy might have observable implications that could been sought for in WMAP or SDSS. Also, if we are just talking about angular momentum conservation from some initial non-zero value, then that would have to be accomplished by ordinary gravitational forces, when would tend to concentrate mass in a plane perpendicular to the axis of rotation, just as galaxies collapse into rotating disks. Dragons flight 15:53, 28 July 2006 (UTC)

I believe the idea that the Universe is rotating was originally put forward by Godel. It is a meaningful question as a reference point is only required for uniform motion. The current thinking is that the Universe is not rotating as (it is thought) the rotation would produce observable change in the cosmic microwave background. This has not been seen.
The suggestion by Dragons flight that the angular momentum be zero is I think a reference to the intrinsic angular momentum (spin). The net spin of all the individual particles in the Universe is zero.
Another reason cosmologists find the idea of a rotating Universe distasteful is that it would mean there would be a 'special place' in the Universe and therefore contravene the cosmological principle.

Thank you everybody for the answers! There's lot to think about this that I can't put into words right now, but thank you for your answers. Santtus 22:28, 2 August 2006 (UTC)

herniated disc

Are there any proven scientific cures or treatments for people who have herniated discs?

Try our article on spinal disc herniation. TenOfAllTrades(talk) 13:05, 28 July 2006 (UTC)

Energy density of alcohol

The food energy of ethanol is usually given as 7kcal/g. The energy of carbohydrates is just 4kcal/g. But alcohol is a metabolic byproduct of glucose - it can be produced exothermically from it by fermentation. How can the product have a higher energy density than the original? --199.89.64.178 15:11, 28 July 2006 (UTC)

Fermentation: C₆H₁₂O₆ (glucose) -> 2 C₂H₆O (ethanol) + 2 CO₂ (carbon dioxide) + 2 ATP (energy).

I assume the issue is with calculating energy per gram rather than energy per reaction. Reducing glucose to ethanol reduces the weight almost in half by removing CO₂, but releases only 2 ATP. By contrast, full aerobic respiration can produce 36 ATP of energy per glucose molecule, so evidentally very little energy is lost converted in converting glucose to ethanol, while the weight is reduced considerably by removing CO₂. Dragons flight 15:38, 28 July 2006 (UTC)

I don't know if it applies to your calculations, but in terms of human metabolism, alcohol is a calorie free "food". It is only when the body (alcohol dehydrogenase, then acetaldehyde dehydrogenase) converts ethanol to acetaldehyde and then to acetic acid, which can be used as "food", that the energy is avaliable to the body.Tuckerekcut 18:40, 28 July 2006 (UTC)

Sorry, this is like saying "starch is a calorie free food; only when it is converted to glucose is the energy available". All caloric food gets metabolically converted. alteripse 12:59, 29 July 2006 (UTC)

"All caloric food gets metabolically converted" is misleading for two reasons. First, there is caloric food which is simple enough to be broken down directly (namely, simple carbohydrates) without metabolic conversion. Second, of those foods which much be converted to offer food energy, a non-trivial fraction often passes through the body without conversion (or with incomplete conversion). That is, when one drinks ethanol, there will be a little ethanol in that person's urine later on (or in their breath right now). It is important to take these things into account when comparing the actual free energy to the food energy.Tuckerekcut 15:24, 29 July 2006 (UTC)

You are either playing semantic games or misusing words. Name a caloric food substance that isn't metabolically converted. Even most glucose molecules are metabolically converted as they are distributed throughout the body and used. alteripse 22:47, 29 July 2006 (UTC)

Dragon flight's reasoning is sound and seems to me appropriate to the question: per gram of substance, the calorific value of ethanol is 1.75x that of glucose.

I believe that calling alcohol a calorie free "food" may be a dangerous statement for persons reading this forum who may need to watch their energy intake. Tuckerekcut's point seems to be that when alcohol enters the calculation, one cannot simply convert from grams of substance to effective dietary kcal. In the intact human being this can be (but is not always) less than expected from simple calorific measurements of the substance itself. This is true. What other sources of calories the person takes in seems to make a difference. I cannot, however, make sense of the idea of energy-giving foods being calorie free "food". Nor that conversion has anything to do with it. In following the metabolic pathway of energy-giving foods down to the common acetyl-CoA molecule, and on to the electron transport chain, there seems to be a whole lot of converting going on. No energy yielding "food" that I have ever heard of, other than intravenous ATP, does not get converted (and even that gets converted to ADP to deliver energy). Alcohol is usually referred to as "nutrition free" calories, implying supply of energy without any other nutrient value - like eating pure glucose. But here calorie free food seems to be defined as food which first needs to be "converted", thereby qualifying as being calorie free. We know that loss of the energy available in food occurs on the way from the mouth to the mitochondrion, caused by processes both normal and pathological. That does not change the calculation of the laboratory determination of the potential calorific value of food. Or does it? Should we refer to fat eaten by a person with a short bowel syndrome and absent colon (or maybe severe chronic pancreatitis), now as calorie free food? Does glucose for a diabetic with too little insulin suddenly become a calorie free food? When is the term used? Is there some reference to the concept available? --Seejyb 22:23, 29 July 2006 (UTC)

I suppose I was getting into the semantics a little there, and that other than intercellular ATP injections everything needs to be converted to yield useable energy. What I would stress, then, is that there really are three measures of the amount of energy in food. One measure is the total free energy of the chemicals which make up the food, that is, the amount of energy required to assemble the food from individual atoms. You might find this in a reference text like the Merck Index. The second measure is the caloric potential of the food (I'm making this term up, if it is previously coined, disregard any other definitions in this context), being the amount of energy which can be extracted from the food by the (human) body under ideal circumstances. This is likely to be close to the number given in the nutrition information on the packaging of most foods (be it in kJ or Cal). The third measure is the actual amount of energy extracted, which is dependent on such things as individual metabolism, pathology, and peristalsis.Tuckerekcut 19:22, 30 July 2006 (UTC)

Portable X Server for Windows?

Moved to the Computing referece desk

EPR spectra have three peaks, why?

Why do "rhombic" epr spectra have three peaks, I would have thought that these signals would be averaged out because of the random orientation of the molecules? Or stated differently, I would expect to see an infinite number of peaks, one for each orientation of that paramagnetic molecule in the magnetic field. Thank you,--130.126.228.60 16:12, 28 July 2006 (UTC)

Electron Spin Resonance (a synonym for Electron Paramagnetic Resonance) could help you, as well as Nuclear Magnetic Resonance, a technique which employs virtually identical physical concepts, except for nucleons, instead of electrons. The paramagnetic elements in a sample undergoing EPR are subjected to a constant magnetic field, which orients most of the samples to have an angular momentum in the direction of the field (the angular momenta are quantized, and they actually form a boltzmann distribution with a peak in the orientation of the magnetic field). The sample is then subjected to EM waves, which cause the parts of the samples for which the frequency is a resonant frequency to strongly absorb the waves. Usually in EPR the frequency is held constant while the magnetic field strength is varied to create different resonant frequencies in the sample. In short, the static magnetic field polarizes the samples and causes all similar samples to resonate at the same frequency. --Bmk 04:26, 29 July 2006 (UTC)

About vision

Always wondered, how with science view can we explain that when in the dark, if we don't look directly on the subject, we can see it clear? and vice versa: if in the dark we directly look at the subject, we see nothing. Why is that? Thank you.

Probably your peripheral vision is better at seeing in the dark because of where the rods and cones are in your eye but possibly the subject is very bright and you are getting blinded by it if you look at it directly. JMiall 17:01, 28 July 2006 (UTC)

Looking directly at something lets you see more detail, while the peripheral vision is just enough to catch your attention when you see movement and then look at the object in question. I suspect you may have looked directly at something bright in the past, and fried some of the receptors in that area, leaving an insufficient amount to see well in the dark. Your peripheral vision, remaining undamaged, is therefore better able to see at night. StuRat 17:54, 28 July 2006 (UTC)

Rod cells are located throughout the retina, but at very low number at the fovea, the center of the field of vision; Cone cells are highly concentrated at the fovea. This allows greater color vision & detail when looking directly at an object and very sensitive, but largely color-blind, vision in the periphery. In very low light, cones are largely useless, but rods can respond to a single photon of light. It's probably most effective, until one gets completely acclimated to low-light conditions, to look at objects a few degrees off to maximize sensitivity. -- Scientizzle 18:20, 28 July 2006 (UTC)

Any astronomer can tell you that dim/faraway stars are best seen peripherally—more rods. — The Mac Davis] ญƛ. 18:27, 28 July 2006 (UTC)

No no no no... this is an effect called averted vision. http://vegas.astronomynv.org/Tutorials/avertedvision.htm It's a commonly used technique in optical astronomy and is caused because the optical nerve (where there are no rods or cones) is right in the center of your vision. --35.9.66.37 14:46, 3 August 2006 (UTC)

Plant Pathology

Hi! Will anyone please explain : What is the basic difference between an Incitant and a Pathogen? Does the term 'causal organism' apply to both ? Thanks,Pupunwiki 16:29, 28 July 2006 (UTC)

According to this site, incitant is "a term used commonly, but incorrectly, to describe the causal agent of a disease. Properly, the term should refer to some other factor which promotes the pathogenic action of the causal agent". So, maybe your answer lies in that? -- Scientizzle 18:24, 28 July 2006 (UTC)

Banks of south-flowing rivers in Europe

Battle of Smolensk contains the following intriguing sentence: "like many south-flowing rivers in Europe, the Dnieper's western bank... was higher and steeper than the eastern." Assuming that 'many' means 'more than one would expect by chance', why? Henry^Flower 22:27, 28 July 2006 (UTC)

• This is just a thought, but quite a bit of Europe is slowly rising both because of Africa's drift north and rise from the end of glaciation after the last ice age. It would only be a very small difference, but maybe it would be enough to affect the river's course, thus producing this effect in some way? Grutness...wha? 07:21, 29 July 2006 (UTC)

Another wild guess. The prevailing winds in Europe are from the west. The wind picks up more speed over water, so the east bank gets a stronger wind an as a result more erosion. But I doubt the effect (if any) will be strong enough. DirkvdM 07:41, 29 July 2006 (UTC)

perhaps Coriolis Effect? -- 84.160.196.152 14:05, 29 July 2006 (UTC)

It is indeed the Coriolis Effect. All other things being equal (including laminar flow of the river, which is impossible) the river will tend to want to flow east. This means that the river will erode more to the east, and deposit to the west, leaving river cliffs on the east and river beaches in the west.

If so, won't the river then move further and further east until it hits higher ground, which initially stops the move, but then starts eating away the base of the higher ground, resulting in an even steeper slope on the east side? DirkvdM 08:57, 31 July 2006 (UTC)

Don't the last two responses predict the opposite of what the original question stated? -- Avenue 11:00, 4 August 2006 (UTC)

Energy

Is there a metal or any substance that converts heat into electricity?

Yup. See Thermocouple.

Also pyroelectricity and piezoelectricity.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Help Me Identify This Plant

Hi guys, it would seem that this is the latest installment in Help Me Identify This Plant. I humbly ask of the Wikipedians to identify this plant for me. It's a house plant of mine that I've had for maybe two years now.

My Plant

Also, why is it becoming discolored at its top? Also, I suspect it's crowded in there, because it looks like it has seperated into multiple plants. Thanks alot for any help! M@$+@ Ju ~ ♠ 23:48, 28 July 2006 (UTC)

I found a picture of Haworthia fasciata on google images, and that kind of looks like it. Any opinions? M@$+@ Ju ~ ♠ 23:57, 28 July 2006 (UTC)

I'd say aloe. More specifically, going by the pictures, aloe variegata. Black Carrot 02:10, 29 July 2006 (UTC)

I've had aloe before, Black Carrot, and this is somewhat different. Yes it is a succulent, but these leaves are rounder with raised white spots. I don't think it can be aloe. Of course I can always snap a piece off... M@$+@ Ju ~ ♠ 02:19, 29 July 2006 (UTC)

I'm inclined to agree with you (Mattman). Haworthia have little raised bumps/spots, whereas the aloe variegata (which is similar in appearance) is smooth. TenOfAllTrades(talk) 02:59, 29 July 2006 (UTC)

Thanks for the second opinions, Black and Ten, I think I'll go ahead and label it as the Hawthoria. M@$+@ Ju ~ ♠ 05:28, 29 July 2006 (UTC)

If it has grown like that in 2 years it likes you, Matt, but please return the compliment and call it Haworthia (Hawthoria, the succulent hawthor(n)?). Your photo looks like H. attenuata fa. caespitosa, and should have little bumps on the inside of the leaves too. The major risk of overcrowding is that the roots block the pot's drainage holes (I can't see how deep the pot is). You can safely separate all those pups. Take the whole lot out of the pot, wash off the soil, gently separate the roots and plant each one in its own pot of sandy well-drained soil. Rememember to cut out any dead leaves (the overcrowding does that) while you are at it - like any succulent the leaves seal off well where you cut them. The "discoloration" (as opposed to drying / dying leaves) is normal, and depends on light conditions. In the wild one can see the same variety growing in an area close together, with those more exposed to sun having more of a reddish-brown tip. --Seejyb 11:48, 29 July 2006 (UTC)

Thank you for your advice, I will certainly get right on the repotting! M@$+@ Ju ~ ♠ 17:16, 1 August 2006 (UTC)

July 29

Nose-breathing aircraft

Early jet fighters had the air intake for the engines in the nose of the aircraft, while later aircraft had paired intakes on the sides of the fusilage. Why the difference? --67.185.172.158 00:32, 29 July 2006 (UTC)

Not all early jet fighters had intakes in the nose. The world's first jet fighter – the Messerschmitt Me 262, flown by the Luftwaffe near the end of World War II – had a pair of engines, one under each wing. The United States' first jet fighter (the P-59 Airacomet) had a pair of intakes along the fuselage. Meanwhile, the British Gloster E.28/39 (Pioneer) had a single nose intake.

Anyway, the reason is pretty prosaic. Both the Me-262 and the P-59 had two jet engines, and one air intake per engine. The Gloster Pioneer, on the other hand, had only a single engine mounted in the middle of the fuselage, dictating the placement of its air intake directly forward in the nose of the aircraft. TenOfAllTrades(talk) 01:59, 29 July 2006 (UTC)

There are many ways to design an airplane- including how many engines and where they are placed. And around the same time as the jet engine was developed, airborne radar equipment was being developed. The best place for the radar antenna was the nose, which caused the air intakes to move to the sides of the fuselage. Some US fighters used different arrangements. The Republic XF-103 had the intake below the fuselage, similar to the F-16 Fighting Falcon. And the North American F-107 had the intake placed on the top of the fuselage, behind the cockpit.

The nose is useful space for istrumentation and it is also very difficult to arrange the airchannels around the cockpit without interfereing with it, so to simplify it when these problems had been realised, the air intakes were placed behind the cockpit. Philc _T^E_C^I 13:52, 29 July 2006 (UTC)

What is the chemical structure and properties of...

N, N'-Methylene-bis-acrylamide FW= 154.2 C7H10N2O2

This chemical is used in Polyacrylamide gels for SDS page with acrylamide.

Refrence: Laemmli, U.K. Cleavage of structural proteins during the assembly og the head of bacteriophage T4. Nature. 277:680-5, 1970.

--129.115.82.89 01:01, 29 July 2006 (UTC) Otis Blanchard

Check out Sigma Aldrich's web site for a fully drawn structure: product number M7279. Or, a formula that should give you some idea of the structure is (CH₂=CHCONH)₂CH₂. It's used as a crosslinking agent when making polyacrylamide gels. TenOfAllTrades(talk) 02:09, 29 July 2006 (UTC)

Gray's Anatomy

In Gray's Anatomy, what is the meaning of "viz." throughout the book? One instance is, "the remaining constituents of the ovum, viz. it's limiting membrane and the solid spot..." Thanks for any help, Newnam^(talk) 01:25, 29 July 2006 (UTC)

Our sister project, Wiktionary, can be helpful, viz. wikt:viz.. TenOfAllTrades(talk) 01:46, 29 July 2006 (UTC)

Thanks! Newnam^(talk) 01:51, 29 July 2006 (UTC)

But if you are really stuck, ask your uncle, viz. viz --Seejyb 11:57, 29 July 2006 (UTC)

Amperes

In electricity, is the amp being pushed from the power supply; or is it pulled from the devise requiring power?

I guess it would be more accurate to say it is being "pushed" from the power supply, but the wording is odd - I would recommend a good read of electricity. --Bmk 04:35, 29 July 2006 (UTC)

I agree. Purely as a mental picture, I tend to envision that current sources push current, while voltage sources require the load to pull current, and real sources do something in between. This picture may or may not be helpful. Melchoir 07:14, 29 July 2006 (UTC)

But "current" isn't a substance which can be pulled or pushed. In home plumbing, what thing is flowing inside of the pipes, is it current or is it water? Water flows in pipes, and it is charge which flows in wires. Charge gets pumped through power supplies and through any loads. A current-source is not a source of current, but instead is a source of constant current; it's a producer of constant unchanging charge-flow.

Back to the original question. A power supply pumps a little charge out of one wire and into the other. The two wires act as the two plates of a capacitor. This pumping of charge produces a voltage difference across the wires, and when this voltage rises to the same value as the power supply's output voltage, the power supply stops pumping. If we then connect a load across the two wires, this allows charge to flow back where it started, and therefore the voltage across the wires will begin falling towards zero. The power supply sees this and again starts pumping charge from one wire to the other. When things settle down, the load device is constantly discharging the imbalance of charge in the wires, and the power supply is constantly pumping the imbalance back up again. So... does the power supply push the charges, or does the load pull them? The answer is yes!  :) Both things happen: the load device draws a certain amount of charge per second from one wire to the other, and this causes the power supply to pump charges at the same rate in the opposite direction so the voltage-difference is maintained. --Wjbeaty 08:36, 30 July 2006 (UTC)

I suppose by 'amp' you don't mean 'amplifier' but 'ampere', ie 'current'. A current is caused by a potential difference. Whether one end is pushing or the other pulling depends on what you call 'normal'. If that is 'earth' and you've got a positive charge connected to earth then the electrical current flowing from the charge to earth might be said to push it. But I believe in household electricity there's a negative and a positive side, so you get a push an a pull at the same time. However, which way does the current flow? The electrical current goes in the opposite direction of the electron current, so which side pushes and which side pulls depends on what you are looking at - the flow of electrons or the flow of 'lack of them'. DirkvdM 07:53, 29 July 2006 (UTC)

QED

2 electrons repel each other because one electron emits a virtual photon (recoils) and the other electron absorbs the photon (more energy, different momentum, changes direction) But WHEN does the electron WHEN to emit the photon? Are they conscious?

AFAIK, electrons are not conscious! My understanding is that electrons repel each other because they have similar charges - not anything to do with photons. -- SGBailey 06:39, 29 July 2006 (UTC)

Similar charges repel? No, you're talking about distant action theory, an obsolete theory from before the time of Faraday. Since Faraday we know that electrons repel each other because electrons are surrounded by EM fields, and these fields interact with particles to produce attraction or repulsion force. More recently we know that electron repulsion is based on photon exchange, and that EM fields are actually composed of huge numbers of virtual photons.

Regarding the original question: we could also ask whether electrons have some sort of hidden "clockwork" which tells them when to emit a photon. This is called hidden variable theory and is disproved by experiments involving Bell's theorem. So how do electrons do what they do? They just do: it's a law of physics with no deeper mechanism allowed. Also, why do electrons persist, rather than winking out of existence? Why do they have constant charge rather than random variation? Why do they experience a particular force at a particular distance from other charges? They just do. But perhaps you'd want to look at Many Worlds Theory which assumes that during any interaction, the entire universe splits into an infinite number of copies, where the interaction happens slightly differently in each universe. Rather than one electron having to decide when to emit, instead there are many separate universes, and the electron emits a photon at a different time in each universe. --Wjbeaty 08:24, 30 July 2006 (UTC)

Actually, hidden variables were not disproven, just local ones. Then again, there is nonlocality in the standard QM interpretation too. I think your other explanations aren't quite right either. (Cj67 03:19, 2 August 2006 (UTC))

Well, the leading Feynman diagram that causes electrons to scatter off each other does involve exchanging a single virtual photon. But that doesn't mean that what physically happens is that one electron emits a single photon, which is absorbed by the other. Instead, the quantum fields at work in some sense figure out the combined result of all possible ways for a photon to be exchanged. Does that make any sense? Melchoir 07:08, 29 July 2006 (UTC)

And all possible ways result in a repel for this case? Very perplexing!

I think the world of Faraday, but he never heard of an electron and did not write or theorize about them.Edison 20:23, 5 August 2006 (UTC)

Electrical signals

Can anyone explain in layman's terms how electrical signals sent to the brain are converted into mechanical reflexes, resulting in movement? Thanks!

The neuron article should be a good one to read. It's pretty complicated, and very interesting, but i'll give a very general overview. Basically neurons have a cell body, the location of the nucleus and where the regular cellular processes take place, they have dendrites, and axons. Signals come in from the axons of other neurons through the dendrites, crossing the synapse, which is just the tiny gap between an axon terminal and a dendrite. If the total stimulus from the dendrites is high enough, the neuron fires, and sends a signal out to connecting neurons through the axon, propagating the signal along. Once it gets to the brain, the brain does its mysterious thing (brains are basically giant conglomerations of billions of neurons connected in complicated ways), figures out what to do about the stimulus, then sends a signal out through motor neurons, which are similar to regular neurons, except they connect to muscle cells at the axon. This connection between motor neurons and muscles is called the neuromuscular junction. Basically, the signal crosses the junction (see acetylcholine, the neurotransmitter which actually crosses), and causes the muscle cell membrane to depolarize, which in turn triggers the muscle cell to release sodium ions into the muscle, causing the muscle to contract. It's really quite complicated... to give you some clues where to look to find more details, the signal which is transmitted is actually an action potential, which is caused by the movement of ions through ion pumps and ion channels in the neuron membrane - the ions act like people doing "the wave" at a baseball game in the stands. Goodness, this is a huge topic. I'd better stop. I hope that was helpful --Bmk 04:52, 29 July 2006 (UTC)

Reflexes (such as the patellar reflex) generally don't go to the brain, but are actually automatic responses from the spinal cord. Reflex arc has more information. -- Scientizzle 05:28, 29 July 2006 (UTC)

Snowing in Winter

I have two questions to ask you:

1.Tell me if the following cities snow (at least one day) in winter or not:

 *Chongqing      *Tokyo           *Oklahoma City  *Barcelona

 *Shanghai       *Seattle         *Raleigh        *Marseilles

 *Seoul          *San Francisco   *Washington, DC *Rome

 *Osaka          *Dallas          *Madrid         *Athens

2.IF most of those cities above do snow in winter, then why?I mean, I live in Sydney in Australia where it never snows in winter.Many of those cities above are on roughly the same latitude and side of a continent as Sydney.So, if snowing is such a normal and common thing in the world and Sydney is not a very warm or hot city, then why doesn't Sydney snow in winter?

60.241.116.24 06:03, 29 July 2006 (UTC)

• There's a section in snow about occurrence. It doesn't explain outright why, but it appears that snow only falls in extreme latitutes or on high mountains. Since Sydney is at or near sea level, it doesn't get snow. There's a great image (image:Earth-satellite-seasons.gif) that gives a n example of where it commonly snows in the world. There's a noticeable change in winter, but in Summer, the only snow I notice is in South America. But according to this list, it does snow in Australia and other places not usually associated with snowy weather. Hyenaste ^(tell) 06:38, 29 July 2006 (UTC)
• Latitude is only one of several factors which affect temperature. I live in the far south of New Zealand, and I'm as far from the equator as the Mediterranean coast of France, yet my climate is more like central England's. Ocean and air currents are as important as Latitude, as is the difference between a maritime climate and a continental climate - it is for this latter reason that Chicago - at 42°N gets more snow in one year than Barcelona (also 42°N) would in a couple of decades. Grutness...wha? 07:30, 29 July 2006 (UTC)

Well it is true that a land mass like a continent causes more severe temperature differences, but the difference between the two sides of the north Atlantic is at least in part also caused by the northern branch of the Gulf Stream that takes warm water to Europe, making it much warmer than it should be. I don't know if this affects snowfall too. Nor do I know if something similar happens in other oceans. DirkvdM 07:59, 29 July 2006 (UTC)

By the way, cities don't snow. I don't know what does, though. The clouds? It? DirkvdM 08:02, 29 July 2006 (UTC)

Seattle gets more than one day of snow per winter. We don't get much accumulation of snow compared to other north american cities that get snow. Typically winters here are mild, because most of the airmass is warmer tropical air from the mid Pacific: This warm, moisture-laden air keeps the winter temperature here mild, but brings lots of rain. However, if the jetstream dips far enough south, then we get a lot of very cold, dry air with corresponding low temperatures but no precipitation (either rain or snow). But if conditions are right, and we get a combination of a very cold airmass that also contains moisture then we can get snow. Typically though, the clouds that bring snow also hold in the heat, making the temperature hover right around freezing, and so we get all these "will-it-or-won't-it" forecasts for snow and often when it snows, it immediately warms up and the snow melts away.

Eastern washington is far different though. The same warm moisture-laden airmass from the pacific ocean that gives us rain cools off when it crosses the Cascade mountain range, and dumps tons of snow on Eastern washington.

- In regards to the American cities listed above in your first question, approximate average yearly snowfall is: San Francisco - trace amount, Dallas - 4 inches, Raleigh - 8 inches, Oklahoma city - 10 inches, Seattle - 10 inches, Washington D.C. - 18.5 inches. I can also say from experience that I have seen snow flurries in Rome.

topic suggestion

Can somebody suggest me a good topic related to electronics? I have to conduct a seminar in my college. The topic must be related to electronics and can also combine electronics with various other fields such as biology, astronomy, geography, military warfare science, communication or anything else but it MUST be related to electrical or electronics. the topic must be interesting. also if u dont mind can u please say in which website I can find manuals or papers related to that topic. PLEASE SOMEBODY HELP ME. I WILL BE VERY GRATEFUL TO YOU. THANK YOU VERY MUCH.

With something like this, it is really best if it is something you already know about and care about, but howabout "the history of computing" from babbage's mechanical devices through relay logic to early valve computers and then transistor and finally IC devices? -- SGBailey 06:35, 29 July 2006 (UTC)

Definitely, I agree with you SGBailey, you might also talk briefly about Quantum computing as the future of Computing!--219.78.205.155 06:45, 29 July 2006 (UTC)Just Love Science

History of computing is a great topic and cross-cuts through all of those fields you are talking about. --Fastfission 10:53, 29 July 2006 (UTC)

I've always found the use of imaginary and complex numbers in electronics to be a fascinating subject. StuRat 07:57, 29 July 2006 (UTC)

Definitely cellular automata, and AI, although that's more computer science than electronics. --18.239.6.57 11:26, 29 July 2006 (UTC)

You could talk about Nikola Tesla, he was an amazing and sometime weird inventor. Many of his demoes are famous in the history of electricity. You will have no trouble to find documentation on him all over the internet. --66.11.173.63 10:32, 3 August 2006 (UTC)

water after excercise

my friend and i once playing table tennis and when we became exhausted i opened the bottle near me and start drinking water.. my friend stopped me from drinking..he said drinking water literally after exercise creates kidney pain...is it true?

Certainly not, this is only for COLD water. If you drink warm water it should be fine. This is because after intensive excercises, your body is still "running" and "agitated". A sudden dose of cold water would contract your organs (only for organs that has contact with the dose of water, wind pipe, throat, stomach etcetera, but the effect compiles on after another, not a sudden phenomenon) based on the fact that "cold contracts, hot expands". So your friend is correct.

I've never experienced this and I find that answer pretty suspect (your internal body temperature does not change that much during exercise, you can raise it a degree or so on a very hot day if you overdo it). If he is talking about developing cramps, that can certainly happen if you mix high water intake with exercise. In my experience though that is only really a problem if you drink a lot of water before exercising (after doesn't seem to affect it). --Fastfission 10:59, 29 July 2006 (UTC)

And that's really cold water, you know, the kind with ice floating in it and condensation around the bottle.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Canada 1930's - History of Fish Oil

Hope you can help.

I am seeking any information you may have of Canadian doctors using Fish Oil for health related matters (cardiovascular or other ailments) in the 1930's.

Thank You

Jeff Edgecombe

Fish oil as cod liver oil was used widely throughout Canada, North America, and Europe in the first half of the 20th century as a general tonic for children. alteripse 11:40, 29 July 2006 (UTC)

Time travelers stranded at the beginning of human civilization. How to recreate civilization/infrastructure quickly?

Consider this sci-fi scenario:

A group of time travelers from the future (say the 2400s) go back in time to the beginning of human civilization on an expedition and get stranded there. They have a craft that is still usable for some time (for shelter and transportation) but they lost the ability to travel in time. There is no realistic hope of a rescue. They have advanced scientific knowledge and have encyclopedic information about the Earth and the history of technology. What they don't have is the advanced infrastructure of their time that would allow them to repair/re-supply their craft, or to maintain their 25th century lifestyle. These time travelers want to recreate a technology infrastructure from scratch, at a greatly accelerated pace, both for themselves and for their children.

What can they do?

(To make the exercise more interesting, consider this: these time travelers know where the natural resources are, and can fool the humans of the time into believing that they are gods and thereby obtain their cooperation.) --71.246.1.25 11:54, 29 July 2006 (UTC)

This theme has been dealt with many times by science fiction writers. I seem to remember one in which the protagonist made a fortune by devising a paper clip or something like that. These scenarios tend to skip over several big problems. First, you don't jump from primitive to advanced technology in a single leap just because you have the knowledge. Advanced technological products require both social and industrial infrastructure, which develops over centures or can be transferred in decades. So what if they settle for only slightly advanced technology? The problem then is the farther ahead you are, the less you are likely to understand primitive forms of your own technology. I'll bet more people can use a GPS system than a sextant-- so as soon as the batteries on the time travellers' GPS system wears out, they are worse off than the locals at exploring and finding things. Just because you can drive a car or use a computer doesn't mean you can build one. So the ideal time traveller might be a historian of technology who has studied the evolution of technology and take whatever exists a few steps ahead faster. Third, the business of being perceived as a god has some inherent flaws. If you think about human history, what happens to "gods" and great prophets? They get co-opted or swept up or crushed by local political forces, or they become a successful political movement, all within a few years. The story of a time traveller successfully leading the local people would be the story of a time traveller converting them into a militarily aggressive and successful society by providing one or two slightly advanced weapons and tactics (i.e., an iron knife instead of a flint one), not someone who pushes them from the stone age to the industrial age in a generation. If successful, he would transformed from an astronaut/explorer/engineer type into an emperor or god/king type for a few years before he met his violent death. Maybe that's the more interesting story. alteripse 12:15, 29 July 2006 (UTC)

Yeah, they'd have a very hard time if they are really at the beginning of civilization. They have no real way to generate electricity, most likely, and without that modern technology is totally screwed. Without the ability to set up extensive mines, you're not going to have the raw metals needed to build even the most rudimentary technologies. Infrastructure takes a long time to build from scratch, especially if you are doing it to build something that nobody else understands the purpose for (and unless you have a lot of barterable currency you're going to have a hard time convincing anyone to do anything for you). --Fastfission 12:27, 29 July 2006 (UTC)

Without electrical generators they'd be pushed all the way back to the 1910 era. Don't forget that the industrial revolution happened before electric energy systems and was based on cast iron. --Wjbeaty 07:59, 30 July 2006 (UTC)

They would probably set up a paradox resulting in the destruction of the universe. Not great for their children. Philc _T^E_C^I 13:48, 29 July 2006 (UTC)

Conceptually similar, albeit less dramatic, scenarios have enfolded time and time again throughout history. European's travelled through technologically evolved "time" when colonising Africa, South America and the Pacific Rim. More often than not, especially when the numbers are small, a significant number of the the technologically advanced colonising party meet a violent death. The indigenous parties usually suffer greatly as they are exposed to technology - and the vices and dangers that accompany them - far too quickly, eventually a strange equilibrium emerges between so-called advanced culture and tribal customs. This type of culture-clash be seen even today in regions of Africa and South America. In other words, empirical evidence would suggest that your time travellers would most likely settle into a lifestyle somewhere between theirs and their hosts. Rockpocket 19:04, 29 July 2006 (UTC)

This was a plot point in A Fire Upon the Deep and A Deepness in the Sky. Planetary civilizations would crash for various reasons, and traders who'd spent a lot of time and resources getting there, and who planned to stay for a decade or two. They had a variety of discovery trees, showing how to get from the Iron Age up to the local limit of technology. Pretty much the sort of thing you're describing. grendel|khan 23:55, 29 July 2006 (UTC)

These time travellers, perhaps they started from a tropic port, aboard a tiny ship? --Wjbeaty 07:59, 30 July 2006 (UTC)

Their time machine was set for 'a three hour tour'...

Don't forget to read "A Connecticut Yankee in King Arthur's Court" wherein the hero did not go back quite so far, but encountered some problems our fearless crew would doubtless have. The King thought the hero was a fine fellow, but the religious establishment resented change. Also Andre Norton wrote about "time traders." Heinlein wrote "Farnum's Freehold" (sp?) No need to worry about time travel paradoxes, because there are an infinite number of alternative universes. "Civilization" might be a term applied to the earliest time when some people appointed themselves the bosses of others, the warrior/cheiftain/priesthood, on religious/military grounds. Before that the people weren't well enough organized for mass warfare and exploitation. So our chrononauts would find rulers who wanted to retain and increase their power, and workers who perhaps wanted to be left alone or to rule in their stead. So one avenue of prosperity is trade: to offer either or both sides slightly better weapons. Hope they have everything from Wikipedia, project Gutenberg, and a lot of industrial handbooks along with some programmable robotic machine tools. Perhaps hire workers extract copper (acheived by 8700 BCE) from the ores whose location you already know, and introduce copper knives, arrows, and plows. Now you can make copper wire, and you're part way to modern industrialization. Extract tin (achieved by 3500 BC) and your customers will want the new improved bronze tools and weapons. Now they are used to mining and metallurgy, so get them extracting zinc (achieved by 1300 BCE). You are all set to make miles of copper wire, and to get power from copper-zinc galvanic batteries. Your workers should be able to make iron, so you can build steam engines, generators and motors, not to mention pistols, rifles and artillery. Those new steel drillbits will help your guys drill for petroleum and refine it in stills. Electronics and computers should be doable, so why not space travel and time travel? How many years would it take to advance technology by say 8000 years? What happens when technology develops in advance of religious and moral philosophy? Vicious amoral tribal chieftains with weapons of mass destruction? Oh wait: that is today's world situation. Never mind!Edison 20:55, 5 August 2006 (UTC)

how do alterations of the CNS account for psychiatric disorders like clinical depression

hi would it be possile for you to tell explain to me the way in which alterstions of the CNS neurotransmission may account for psychiatric disorders using the xample of clinical depression. I have looked at your information about clinical depression but it appears that you do not discuss this aspect, thanks for you time and i eagerly wait for you reply. from laura

Short answer: the cause of depression isn't really known at the neuronal level. But since you asked about neurotransmission, I'd suggest taking a look at serotonin (a neuromodulator, not a neurotransmitter), which is implicated in depression. Dopamine too, to some degree, although it's most associated with Parkinson's disease. Digfarenough 12:49, 29 July 2006 (UTC)

We have indirect evidence that in severe depression there are lower levels of at least one neurotransmitter, serotonin, and perhaps others such as norepinephrine. The strongest evidence is that the most effective antidepressant drugs (SSRIs) seem to work by increasing the amounts of serotonin in the neuronal synapses. That is the short answer. A full answer is more complex and beyond my power to make something complicated intelligibly simple. There is some additional detail in our clinical depression article, which looks like a reasonably good overview, and if it hasn't changed recently, I recall we have a detailed article on psychopharmacology. alteripse 12:54, 29 July 2006 (UTC)

You might also wish to read the biological psychiatry article for an overview of the theory and practice of understanding mental disorder in terms of biology. Note that this explanation for psychiatric disorder is notwithout its critics, see Biopsychiatry controversy. Rockpocket 18:39, 29 July 2006 (UTC)

i need a new trend in electronic field because i need to take a seminar

Can somebody suggest me a good topic related to electronics? I have to conduct a seminar in my college. The topic must be related to electronics and can also combine electronics with various other fields such as biology, astronomy, geography, military warfare science, communication or anything else but it MUST be related to electrical or electronics. the topic must be interesting. also if u dont mind can u please say in which website I can find manuals or papers related to that topic. PLEASE REMEBER THAT IT HAS GOT TO BE SOMETHING NEW AND INTERESTING. TOPICS SUCH AS "THE HISTORY OF ELECTRONICS" WON'T DO. I NEED TO EXPLAIN IN SCIENTIFIC AND MATHEMATICAL TERMS ABOUT SOME NEW INVENTION OR TECHNOLOGY OR CONCEPT OR ANYTHING INTERESTING. MUST BE RELATED TO ELECTRICAL OR ELECTRONICS.PLEASE SOMEBODY HELP ME. I WILL BE VERY GRATEFUL TO YOU. THANK YOU VERY MUCH.

You got 5 interesting topic suggestions above. Now you need someone to write it for you? You can YELL at us all you want but you are in the wrong field if nothing yet has interested you enough to be able to teach people about it. Drop your course, learn to repair computers or something and stop bothering us. Harsh, I know, but there are limits to the "do my homework" pleas. Next week someone will ask us for a PhD thesis suggestion, and then the website where they can find the already-done research. alteripse 15:06, 29 July 2006 (UTC)

What about smart cards? BenC7 09:44, 31 July 2006 (UTC)

Toxicity levels of these vitamins

Does anyone know if the following levels of the following vitamins are dangerous? Their respective articles don't tell. I do heavy lifting 4-5 times a week if that has any impact... I'll leave that for ye wise to determine...

Thiamine (B1) - 15mg Riboflavin (B2) - 10mg Pantothenic acid (B5) - 25mg Pyridoxin (B6) - 11.8mg (of which 10.5mg is pyridoxal-5-phosphate) Biotin (B7) - 100mcg Folic acid (B9) - 500mcg Cyanocobalamin (B12) - 100mcg

You see all, I'm considering a new multivitamin and this new one contains significantly higher levels of the above vitamins than my current one does. Don't wanna poison myself, or waste my money for that matter. Jack Daw 15:17, 29 July 2006 (UTC)

Nothing you've listed is even close to toxic levels (I'm assuming a once-a-day dose). Toxicity is mostly a problem with fat soluble vitamins, not water soluble ones. - Nunh-huh 15:56, 29 July 2006 (UTC)

If Americans invented the Hovercraft, did the British invent aircraft?

Over the months I've noticed that the Hovercraft article has been gradually edited to make it appear that the role of Christopher Cockerell in inventing the hovercraft was only that of doing some minor tinkering to produce a working hovercraft (that travelled across the english channel in the 1950's).

By this logic, couldnt it be equally claimed that the British invented powered flight and that the Wright Brothers only did a bit of tinkering?

Oooh, after writing the above I re-read the Hovercraft article, and saw the article has now been re-written to give CC more credit. There has also been a considerable battle on the discussion page http://en.wikipedia.org/wiki/Talk:Hovercraft about this which I had not seen.—Preceding unsigned comment added by 81.104.12.22 (talk • contribs)

Yes, the talk page is the best place to discuss this. If you still have problems, try asking at Wikipedia:Peer review.--Shantavira 17:50, 29 July 2006 (UTC)

I was not being sarcastic - it is a serious question. Thanks.

No, no, some German guy was the first to fly. He just didn't get the media attention, so he has almost been forgotten. Can't remember his name, though. I'll look into that tomorrow. DirkvdM 19:11, 29 July 2006 (UTC)

Mmm. it wasn't Richard Pearse, because he was a New Zealander (and he also flew before the Wright brothers). Otto Lilienthal, perhaps? Or maybe Karl Jatho (although he was also after Pearse). Grutness...wha? 01:50, 30 July 2006 (UTC)

These article illustrate how silly the question really is. Times were right for human flight to take off (pun :) ). So it happened all over the world in a very short time span. I suppose the ones who were most into publicity won the popular title. It's like with evolution. The theory was well known. Charles Darwin, however, wrote it down in a book, so he got the title. Lilienthal didn't use a motorised plane, Jatho's may not have been a controlled flight, Cockerell didn't fly very high and Pearse forgot to photograph his achievement (the publicity bit). What is flight? How high and how far do you have to fly (does a hovercraft count?) Are you allowed to crash-land? And does it have to be repeatable, to the extent that almost every flight is successful? (When was that achieved anyway? A more important issue, I'd say.) So who was first? They all were. The Wright brothers included. DirkvdM 09:48, 30 July 2006 (UTC)

Sound of explosions

Watching TV footage from Beirut (and in most other similar cases where an explosion is filmed from afar) the sound recording of the explosion is superimposed onto the video footage such that there appears to be no delay - as if the cameraman was actually at the scene of the explosion. Who are they fooling? Is it just to make "better" TV, or is it done so that we, the viewers, cannot work out how far the cameraman is from the explosion?--G N Frykman 18:10, 29 July 2006 (UTC)

I have always assumed the audio and video was recorded independently in such situations. Thus, in the editing suite, the are combined, and the editor simply cues up the sound precisely with the explosion, rather than try and gauge the delay. Can any foreign correspondents shed light on this? Rockpocket 18:32, 29 July 2006 (UTC)

scientific question!

How many roads must a man walk down Before you call him a man?

4.20x10¹ Black Carrot 20:26, 29 July 2006 (UTC)

None, being able to walk down roads is not correlated with being a man.-gadfium 00:02, 30 July 2006 (UTC)

Given the number of infants who neither walk at all nor claim to be men, I would expect a slight correlation. Melchoir 00:12, 30 July 2006 (UTC)

Don't forget the women.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Ah, you mean because the average trip from the bedroom to the kitchen is insufficient training for walking down an entire road? Tsk tsk, what a terrible thing to say. Melchoir 04:56, 30 July 2006 (UTC)

If you estimate an average walking speed of about 4 mph and estimate that most children can walk around the time of their first birthday, then you can say that after walking down around 37,000 miles worth of roads you should legally be an adult in the United States. In reality the number would be far less than that, since you'd have to take breaks to eat, rest, attend school, etc. If you divided this by the average road length, though, you'd have an idea of how many roads you'd have to walk down, if you were continuously walking from around age 1, to become 18 years old, as a factor of time. --Fastfission 02:54, 30 July 2006 (UTC)

The answer, my friend, is blowin' in the wind. User:Zoe|^(talk) 03:30, 30 July 2006 (UTC)

You beat me to that one, but let me point out that the question states "how many roads", not "what distance". DirkvdM 08:55, 30 July 2006 (UTC)

follow up scientific question!!

Yes, 'n' how many seas must a white dove sail Before she sleeps in the sand? Exact scientific answers only please--172.163.144.21 20:03, 29 July 2006 (UTC)

White doves are not asexual.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

White doves can no doubt be convinced to sleep in the sand if there are no other options, so you can probably get them to do that without sailing any seas. --Fastfission 02:54, 30 July 2006 (UTC)

White doves don't sail, afaik. so this is sort of like dividing by zero. So there is no answer. In other words, it's still blowing in the wind (ha! I'm the first one this time). DirkvdM 08:55, 30 July 2006 (UTC)

If you use the verb "sail" to mean, "travel on boats", there was at least one (and probably two) on Noah's Ark. User:Zoe|^(talk) 21:12, 30 July 2006 (UTC)

Ah, and (assuming the correctness of the story for the sake of the argument) if all land were covered by water then there was just one sea, so the answer is one. Which leaves the question why the dove was so stupid to return to the boat after it found some sand to sleep in after its long flight. DirkvdM 09:03, 31 July 2006 (UTC)

Maybe it was a homing pigeon.  :) User:Zoe|(talk) 03:13, 1 August 2006 (UTC)

science project

i m required 2 submit a science project innovative in nature....i have an idea AN ELECTROMAGNETIC GUN..using an copper coil and a iron bullet ...indeed high voltage is required...that can b taken from ny T.V set...(circuit that powers the picture tube).range and firing force could b elecronically adjusted...could b upgraded by connecting with a computer..plz comment and lemme kno about its various features that i must not have came into my mind..

It's already been invented - check out gauss gun for info. --Kurt Shaped Box 22:43, 29 July 2006 (UTC)

Note, it is highly dangerous to experiment with high voltages and ampereages, you really need to know what you're doing if you want to try to make a coilgun. And if you do, please add pictures to the coilgun page--we don't have any Thanks,

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

AFAIK, you'd have to make it pretty long in order to accelerate the bullet to a decent speed (i.e. enough to kill your hypothetical target). It would require a rather large amount of electricity too (fancy lugging around a large battery pack strapped to your back?). Abandon all thoughts of your own gauss pistol... ;) --Kurt Shaped Box 01:03, 30 July 2006 (UTC)

It's a school project. I don't suppose the goal is to kill any targets (hypothetical or not). It'll more likely be measuring speeds against voltages and such. But apart from the high voltages, bullets flying around is indeed a safety concern. DirkvdM 09:02, 30 July 2006 (UTC)

Not only that, but if you bring any form of a gun anywhere near a school you will likely be expelled, no matter what the reason, at least in the US. Time to pick another project. StuRat 04:55, 31 July 2006 (UTC)

Good. Now if only they can apply that exclusion zone to all other humans, all buildings and other structures, all animals, all forms of transportation, all geographical features, water, air, any form of matter whatsoever .... JackofOz 06:29, 31 July 2006 (UTC)

I think I f-ed my windows install

Moved to Computer/IT RD--207.75.179.117 22:29, 29 July 2006 (UTC)

July 30

What species is a seagull with a gray band around its beak?

What kind of gull has is mostly white with gray on the wings, black tail feathers and a grayish-black band around its beak? I saw it at Misquamicut State Beach in Rhode Island. Is it a normal variation on the other gulls in the area (they had a reddish spot on the lower part of the beak; I don't know what kind they were), or a different species? If so, which species? grendel|khan 00:14, 30 July 2006 (UTC)

Where's KSB when you need him eh?

You called? :) Check out Ring-billed Gull, especially the third picture in the gallery at the bottom. Look like the fellas you saw? --Kurt Shaped Box 00:57, 30 July 2006 (UTC)

Like twins, except that mine has no spots on the head---it's uniformly white. Is it still the same bird? grendel|khan 01:45, 30 July 2006 (UTC)

Most probably. The adults of many species of gulls have dark feathers (streaks/spots) on their heads in winter. The all-white head is the breeding plumage. --Kurt Shaped Box 01:51, 30 July 2006 (UTC)

Einstein's attempted T.O.E.

Hello, and thanks in advance. I know that Einstein worked on a theory of everything, and worked with Rosen on it, and postulated that particles were small worm holes. My question is, what was this theory called? I tried searching, but i wasn't able to find it. Any help will be apreciated. --AmateurThinker 00:17, 30 July 2006 (UTC)

Einstein and Rosen's activity together was not concerning a theory of everything, however what you are looking for is probably at Einstein-Rosen bridge or their work regarding the EPR Paradox.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Einstein's own TOE was simply known as the unified field theory. --Fastfission 03:01, 30 July 2006 (UTC)

Thank you, but all I wanted to know was what the postulate of particles being Einstein-Rosen Bridges was called. AmateurThinker 22:48, 30 July 2006 (UTC)

Diving fitness requirements

what are the fitness components for diving inorder of importance

Please do your own homework. The answer you are looking for probably came from your teacher or textbook. The question is too vague if otherwise. Also, try our diving article! Thanks,

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Gulls - carnivores or omnivores?

I've just been reading a few of the gull articles on Wikipedia (swatting up on my specialist subject - heh). I notice that in some places gulls are described as omnivores, in others carnivores. Anyone know which one is technically correct? I'd personally lean more towards 'carnivore' as gulls are, by nature meat eaters. They were 'designed' to scavenge from carcasses and prey on small mammals/birds/fish - one look at the beak shape and the observation of a gull's aggressive demenour should tell you that. The fact that they have learned to feast on whatever we throw out, be it animal, vegetable or mineral is neither here nor there IMO. Any thoughts? I think the definition needs to be standardized across the articles... --Kurt Shaped Box 00:23, 30 July 2006 (UTC)

No expert here, but I'd say if an animal will eat both meat and non-meat foods (and can actually digest them) it is an omnivore. So you could turn this around and say that the fact that some gulls only eat meat doesn't necessarily mean they aren't omnivorous. DirkvdM 09:07, 30 July 2006 (UTC)

(after edit conflict) The fact that some gulls have learned to eat other stuff does seem relevant, because those that come and finish off a pizza are omnivores, while those who spend their life at sea and eat only fish are carnivores (or ichthyophagists, if you prefer). --Shantavira 09:11, 30 July 2006 (UTC)

Is that the same as a piscivore: [8]? StuRat 04:49, 31 July 2006 (UTC)

Blah - fish *is* meat. Don't let those damn veggies convince you otherwise... ;) --Kurt Shaped Box 15:26, 31 July 2006 (UTC)

Well, so are insects, but biologists still insist on treating insectivores as distinct from carnivores. —Ilmari Karonen (talk) 19:50, 31 July 2006 (UTC)

Are they really? I think of them more as exo-skeletons full of mucous. Is there really any meat in them? Maybe in grubs. Mmmmmm, all this talk has made me hungry!--Anchoress 20:07, 31 July 2006 (UTC)

Evolutionary relationship between skuas and gulls?

I'm aware that both the skua and gull family are members of order Charadriiformes - but how closely are they related? Did both have a common ancestor or did one family evolve from the other? I see great black-backed gulls on a daily basis and I have had the opportunity to observe the great skua and aside from the colouration, the similarities in size, shape and behaviour are uncanny. To a non-scientist, they seem like very closely-related birds indeed. Then again, compare the skua to the small, timid black-headed gull and they seem worlds apart. --Kurt Shaped Box 00:39, 30 July 2006 (UTC)

According to the tables in p.9 of the first reference in Charadriiformes, gulls are more closely related to skimmers and terns than to skuas. Skuas, for their part, might be more closely related to auks than gulls, but it's not clear. You might want to also check the refs in Lari. Melchoir 01:26, 30 July 2006 (UTC)

I've never been able to understand those tables - any tips? :) --Kurt Shaped Box 12:46, 30 July 2006 (UTC)

Just find the two families you want to compare. Start at one and just sort of walk back along the line until you get to a level from which you can reach the other family. When comparing how close family A is to families B and C, see how far out you have to go to get from A to B, then from A to C. The farther you have to go, the less closely related the two families are (well, the less similar they are in whatever measure is being shown). I'm not sure I explained that totally well... :) digfarenough (talk) 15:10, 30 July 2006 (UTC)

Yes, but .........

You release a toy balloon and it flies around frantically. It will do so even in a vacuum (deep space for instance), because the pressure inside the balloon moves it away from the escaping air. If I have that right, then I think the Thrust article needs to make this clear, because unless you read it carefully it seems to infer/suggest that it is the expelling air that is pushing (on something outside the balloon). Pedants go away please, but would appreciate comment from others. Rense 00:42, 30 July 2006 (UTC)

This should go on Talk:Thrust. Yes, you're right. Newton was the one who declared this.Nathan Rosen

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

I would have thought that a toy balloon would immediately explode in deep space, and the air would ignore the fact that the neck was open. But if any air did manage to come out of the neck, the balloon would move away so that the centre of mass of all the air was preserved. G N Frykman 08:55, 30 July 2006 (UTC)

You're forgetting the mass of the balloon itself. So the centre of mass of the shreds of the balloon and of the air will move in opposite directions. DirkvdM 09:19, 30 July 2006 (UTC)

Feasability of man-portable miniguns...

Just trying to refresh my knowledge here. IIRC (correct me if I'm wrong here), a man-portable minigun would *just* be within the realms of possibility, right? Assuming that the gun itself weighs approx 100lbs and the ammo pack and batteries to spin the thing up were located in a backpack weighing approx 150lbs (I seem to remember those figures from an article on this subject I read years ago) and the soldier in question was selected specifically for his size, strength and endurance, then a minigun could potentially be used as an (albeit impractical in the majority of situations) infantry weapon, right? --Kurt Shaped Box 01:14, 30 July 2006 (UTC)

It sure is. Go out and rent Terminator 2: Judgment Day. Actually, rent the whole series. It's worth it. --mboverload@ 01:18, 30 July 2006 (UTC)

Yup, great movies - I've seen Predator too. :) I was thinking of the feasability of using a man-portable minigun for suppressive fire - a couple of 180-degree arcs of fire from a 2000RPM minigun towards a hidden foe (e.g. hiding in the undergrowth) would pretty much clear out everything, wouldn't it? Or at least cause them to retreat. Your own position would of course, have to be well-stocked. --Kurt Shaped Box 01:29, 30 July 2006 (UTC)

Indeed. I have never really thought about why miniguns are not in more wide deployment. Seems like a good thing to throw in the back of a hummer and get out when you have to hold a position. --mboverload@ 04:00, 30 July 2006 (UTC)

It isn't more widely used because you run out of bullets too fast. Which is mentioned in the article. Rmhermen 06:31, 30 July 2006 (UTC)

the logistics of resupplying the soldier in the field would be difficult, as well as the amount of ammunition the soldier would need to carry to make it an effective weapon, given a regular light machine gun firing at around 800 rpm carries upward of 1200 rounds, scaling that up would give an enormous weight. and you have to wonder whether there is any advantage over existing weapons, which i'd doubt. Xcomradex 09:23, 30 July 2006 (UTC)

I suppose. To take down an enemy soldier, you'd probably need to hit him with a quick burst from an assault rifle, just to make sure (unless you were a very good shot) - maybe four or five rounds. A direct hit from minigun fire would turn him into a pile of meat, which I guess is overkill and a waste of ammo. Going back to the Terminator movies (thinking of the future scenes), the use of miniguns against advanced robotic/cyborg infantry actually does make a lot of sense, considering the amount of damage that the endoskeletons can take and still function. In this case, tearing the enemy to shreds with a solid wall of fire would not only be advantageous - but entirely necessary. --Kurt Shaped Box 11:28, 30 July 2006 (UTC)

I believe I read under trivia in the Terminator 2 article that Arnold was the only one on the set that could lift the weapon--he had to move it everywhere.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Really? You'd think that they could have afforded to hire a couple strong college kids to haul it around the set. And think how cool it'd be to list your last job as "Mini-gun wrangler" on your resume.

Hookes Law?!?!?!!

Helllooo. Can someone tell me the simple idea of what Hookes Law is please. I'v already searched it but I just cannot get the bloody gist of it lol. - Thanks Joel

You've read Hooke's law, then. Where are you getting stuck? Can you be more specific? If you can't be, I'm afraid you'll probably just get the first paragraph of the article quoted at you. If we had a better way of explaining it, we'd put it there. grendel|khan 01:44, 30 July 2006 (UTC)

The more you pull something, the more it will stretch. (As long as it's a relatively "Hookean" material!)--Shantavira 09:18, 30 July 2006 (UTC)

Or perhaps "the further you pull on something, the harder it pulls back" --Bmk 12:43, 30 July 2006 (UTC)

Yup, to be even more exact, the force you exert of a body is proportional to the extension of the body. Think of a spring. The harder you pull (greater force), the longer the spring becomes (extension from 0). And the relation between the force you exert and the extension is proportional! Ask for any help =]

Retinitis Pigmentosa Gene Therapy

To date, what is the current state of gene therapy clinical trials for Retinitis Pigmentosa? (4.152.123.249 22:18, 29 July 2006 (UTC)).

Hello. I'm not an expert in the field, bit i had the pleasure of meeting a certain Professor Robin Ali, of the Institute of Ophthalmology, London, not so long ago and discussed his very impressive work. He is very much leading the way in gene therapy for retinal disorders. An overview of his work can be read here, some of his scholarly papers on animal models [9] [10] [11]. This source [12] (pdf) suggests that human trials are underway or planned for retinal diseases, but not RP specifically. This source [13] seems to suggest that human gene therapy for RP will be (or has been) tested. There is also more impressive work in dog models of Leber congenital amaurosis, according to these sources [14] [15] human clinical trials for RPE65 gene therapy were targeted to begin in 2006. It is probably a bit early to know how successful these have been. Rockpocket 03:40, 30 July 2006 (UTC)

How many calories??

Ive been reading the Calorie page and also reading up on Atwater system to calculate food energy values. But im wondering, is there a way or a formula to see how much a certain body mass (a person) is burning calories just by its normal functions, sleeping, breathing, pumping blood, other. So a person that weighs x kilos and its height is y cm, burns z calories during a 24 hour period. - Avalean - 30th July

There are things like that on the net, but they're not very accurate, because basal metabolism (resting metabolism) has many other variables besides body size. For instance, men and women of the same mass usually differ; people with higher fat percentages or higher muscle percentages; hormonal imbalances can change a person's metabolism. I've seen charts on the net but I hesitate to find them for you because I don't think they'd really be accurate. That having been said, we have an article on Basal metabolism that probably answers your question, although the article is tagged for needing cleanup, and the main formula mentioned says something about surface area of the body (sq m.) when I'd think it should be cubic metres, but what do I know? I just skimmed it anyway. But I noticed the article has some external links. Happy reading.--Anchoress 03:15, 30 July 2006 (UTC)

Anchoress is correct in stating that any simple height/weight/sex/age formula is going to have poor accuracy (I'd guess +/- 20% for people in the "normal" ranges of activity, size, etc.). You could try the Harris-Benedict Equation, it's a classic. -- Scientizzle 21:47, 30 July 2006 (UTC)

The reclusive lady is right, I think. Mass (which is related more to volume than BSA) matters more than body surface area. The BSA theory stuck as gospel following some heavy abstract theorising in the 19th century, and Harris-Benedict sort of preached on, without questioning the basic tenets. It seems as if general biologists these days don't even consider BSA as a real factor, but doctors and dieticians and bodybuilding product sellers carry on regardless. I see on the Basal metabolic rate article talk that it gets 5th place on Google searches at times, but to me it is pretty dense and confusing - not comparable to what I see in academic literature on the subject. I suggest Avalean should look to one of the recent mass related formulas, ignore height, and remember that an individual is not a statistic, so that just a table of values by age and weight is probably as good/bad as any formula. --Seejyb 02:26, 31 July 2006 (UTC)

I seem to recall a method of calculating calories burnt by measuring the exact amount of heat given off by a person at rest, which should be directly proportional to the number of calories burnt. This test, of course, requires a laboratory and the proper equipment. StuRat 04:32, 31 July 2006 (UTC)

Thanks a lot - Avalean - 31th July

Stomach

Is it possible to live life without a stomach?--68.79.234.100 03:46, 30 July 2006 (UTC)

Actually certain people do it to some degree all the time. --mboverload@ 03:59, 30 July 2006 (UTC)

Not just to some degree (gastric bypass) but also entirely (prevention of stomach cancer). The surgeons fashion a small pouch out of the esophagus and intestine. People without stomachs have to eat many small meals throughout the day, and avoid foods that the intestine can't digest by itself. --Allen 06:01, 30 July 2006 (UTC)

A person can actually live quite a long life without the use of a gut on total parenteral nutrition. Essentially, the individual is "fed" a nutrient solution intravenously. – ClockworkSoul 19:30, 31 July 2006 (UTC)

Info about unexplained undersea sound

I recall reading a piece online (probably here at Wikipedia, actually, but not sure) about a very unusual sound that was recorded somewhere off the southern coast of South America. IIRC, it was called a burp or a belch or something of that nature. The article mentioned that some people think it may be the vocalization of some enormous creature. Can someone provide more info? I've searched Google and Wikipedia, but I don't recall a lot of specifics, which makes searching pretty difficult. ISTR that there was a site online that provided a .WAV of the sound as well. TIA. Matt Deres 04:19, 30 July 2006 (UTC)

The article is Bloop. Rmhermen 06:27, 30 July 2006 (UTC)

Bleep!!

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Electricity

Who is the father of electricity?

Of electricity, you say? I haven't the foggiest. But good luck with your homework, in any case. grendel|khan 08:05, 30 July 2006 (UTC)

Thats subjective... Gerolamo Cardano, William Gilbert, Otto von Guericke, C.F. du Fay, William Watson, Benjamin Franklin, Ebenezer Kinnersley, Faraday, Volta, Ampère and Ohm could all have claims on that title. Such is the way the scietific method works; Take your pick. Rockpocket 08:06, 30 July 2006 (UTC)

(edit conflict x2) If you ask Google you get four different answers in the first 10 results: Benjamin Franklin, William Gilbert, Thomas Edison, and Ernst Werner von Siemens. The fact that there are only 364 hits for "father of electricity" suggests that no one is uniformly recognized by that title. Our own List of people known as father or mother of something, which should be fairly reliable, does not list anyone.

If you're trying to come up with your own answer, one starting point is Electricity#History. Melchoir 08:11, 30 July 2006 (UTC)

Lightning? And the mother would then be the 'ground' (mother Earth)? DirkvdM 09:25, 30 July 2006 (UTC)

But Category:Thunder gods has 43 entries... Melchoir 09:27, 30 July 2006 (UTC)

Strangely, this doesn't seem to be in our article List of people known as father or mother of something. If you find out, please add it.-gadfium 09:42, 30 July 2006 (UTC)

Nikola Tesla should be on the list too, if not as a father, then at least a great-Uncle or something.

I think Franklin and Tesla are the only ones that I have heard as "father of electricity."

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Whoever it was, he was one bright spark. *gets coat* Rockpocket 18:17, 30 July 2006 (UTC)

Guglielmo Marconi was the father of Maria Elettra Elena Anna Marconi. -- Nunh-huh 04:55, 31 July 2006 (UTC)

And the father of Electra was Agamemnon. DirkvdM 09:06, 31 July 2006 (UTC)

InputStreamReader

--Tulika 99 11:34, 30 July 2006 (UTC) halow!! i wud like 2 ask what statement shud b used after

InputStreamReader reader=new InputStreamReader(System.in); BufferedReader buf=new BufferedReader(reader);

after this v usually use

V1=input.readLine(); int a=Integer.parseInt(v1);

but its not gettin compiled. can u plzz suggest another statement.

thnk u!!

A few possible problems (I assume this is java):

• You have not declared the string V1
• "input" doesn't exist - that line should be

V1 = buf.readLine();

• you may need to handle the IO exception from the readline statement
• java is case sensitive, so v1 is not the same as V1

fix one or more of those and you may be good to go. Here's what I think it should look like instead:

Add the phrase "throws IOException" after the argument parenthesis in the method head

       InputStreamReader reader = new InputStreamReader(System.in);
       BufferedReader buf = new BufferedReader(reader);
       String V1 = buf.readLine();
       int a = Integer.parseInt(V1);

You can also use a try/catch block, if you know how. Good luck --Bmk 12:34, 30 July 2006 (UTC)

thnk u soo much Bmk !!!!!!!!!

No problem. Enjoy java - it's my favorite. --Bmk 15:31, 31 July 2006 (UTC)

Is a seagull a 'vulture'?

Moved from Humanities.

I mean it acts like a vulture (circles, eats caracsses and carrion). If the vulture had been discovered before the seagull, do you think that explorers would've named the various breeds of seagull 'sea vultures' or something? New world vultures are not real vultures either but they're called that because they act like vultures and the name stuck over the years. What do you think?

Eh - seagulls do a fair amount of hunting and foraging - they kill and eat crabs and shellfish (see seagull). I don't think they eat enough carrion to qualify them as a vulture-type bird. Whoa - I'm surprised there are any gull species links that don't exist given the number of gull fanatics on the desks! --Bmk 12:53, 30 July 2006 (UTC)

Vulture is a whole seperate few families. I think I'll move this to Science.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

The point I was (badly) trying to make is that the biggest seagulls fill the same niche in Northern Europe as 'vultures' do in Africa and 'vultures' do in N.America. The 'vultures' in N.America are only called 'vultures' because the first western people to see them thought they looked like the vultures they already knew about. If we define a 'vulture' as a "scavenging bird, feeding mostly on the carcasses of dead animals." as the vulture article does, then why are seagulls not classified as 'vultures' when they clearly fit the critera (in their natural habitat)? I reckon it's only because seagulls were discovered before vultures - if they didn't already have a name, they'd have been devined as 'vultures', I think. --84.67.154.51 17:19, 30 July 2006 (UTC)

By that rationale, on discovery vultures could, or should, have been named as a type of gull! Historically animals would be named by their lay-discoverers after animals they already knew about, usually based on single, or groups of, defining characteristics. This may have been because they actually thought they were closely related to these animals, or simply as a way of identifying them with some meaning. These days were know that convergent evolution can lead to highly divergent animal species (in terms of evolutionary relationship) appearing very much alike as they fulfil a similar niche. Since we continue to refer to most animals by their traditional names, it can get confusing. However scholarly studies use scientific names for animals, which better reflect their phylogeny. Old and new world vultures are a good example of this. Old World vultures (Accipitridae) are of the genera: Gypaetus, Gyps, Torgos, Aegypius, Neophron, Gypohierax and Necrosyrtes while new world vultures (Cathartidae) are of Cathartes, Coragyps and Sarcorhamphus. Seagulls are from a completely different order (Charadriiformes) Thus, scientifically, there is no confusion between them. Consider also the aardvark (earthpig) and Killer Whale. Rockpocket 18:46, 30 July 2006 (UTC)

They were really running out of ideas when it came to the wildebeest, weren't they? "Hmmmm - a wild beast. What should we call it?" :) --Kurt Shaped Box 21:31, 30 July 2006 (UTC)

I guess with all the good names already gone, they had to think up a gnu one.... Rockpocket 23:18, 30 July 2006 (UTC)

Not aganother g-nu joke. Please come back, Michael and Donald.  :--) JackofOz 06:18, 31 July 2006 (UTC)

Reoccuring question topics on Science

It seems like we get a lot of seagull and masturbation questions on here. Anybody else notice this, or is it some illusion I have fallen for?

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

If 15% ("72% of statistics are made up on the spot") of article edits are vandalism why wouldn't 15% of questions be from kids who think, "let's see if we can make grown-ups talk about flying rats and wanking". Don't mind it, just answer; even if the person asking doesn't learn anything from the answer the rest of us will. Weregerbil 18:33, 30 July 2006 (UTC)

I've noticed it as well, but why seagulls? If a kid wants to ask a silly question then giggle at the serious answers, why would he choose seagulls? Spanking the monkey, sure, but seagulls? Hyenaste ^(tell) 18:42, 30 July 2006 (UTC)

To be fair, most of the seagull questions are posted by one particular user. --Ginkgo100 ^{talk · contribs · e@} 18:48, 30 July 2006 (UTC)

Yeah, I agree with you on that. But, I think some of the other users cured him. ;-) Jayant,17 Years, India • contribs 21:07, 30 July 2006 (UTC)

Particularly funny is when there are a spate of very similar questions, often utilitising the word 'discuss', and you just know that some teacher has set a Wikipedia-savvy (well, savvy enough to know about it, but not enough to disguise homeword) class a particular problem. --Sam Pointon 21:16, 30 July 2006 (UTC)

In answer to all the above, what can I say? I'm a gull fanatic. :) I spend a lot of time observing my locals birds and I've decided that I want to know as much as it's humanly possible to know about them (much of the literature tells me about what gulls *look like* or where gulls can *be found*, but very little about the lives of the actual birds themselves). I've raised baby gulls almost from the egg to re-release into the wild - I think that they're amazing birds, with a strange charm that I don't think anyone else could possibly understand unless they'd done the same thing themselves. I know a fair bit about gulls already but my head is filled with questions, which some of the guys here seem able to answer for me (it's much appreciated - this desk seems to be one of the more knowledgable gatherings of human beings on the internet). I assure you that I'm not asking silly questions for the sake of asking silly questions, or for kicks and giggles. I have no idea who keeps bringing up masturbation - I can't say that I've noticed that many threads about it recently. --Kurt Shaped Box 21:19, 30 July 2006 (UTC)

You need to go to Wikibooks and write a book on seagulls to get them out of your system, since the elctroshock therapy has failed to do so. :-) StuRat 01:21, 31 July 2006 (UTC)

Your gull questions aren't silly though. Hmm... did you ask the unsigned gull question just above this one? If not, gull-mania must be catching on. Hyenaste ^(tell) 23:02, 30 July 2006 (UTC)

Not guilty, sir. Maybe I'm starting a movement... :) --Kurt Shaped Box 15:28, 31 July 2006 (UTC)

Maybe we can kill two birds with one stone (or at least make them go blind) by posting questions on the masturbation practices of seagulls ?  :-) StuRat 01:21, 31 July 2006 (UTC)

I only find one google hit for "masturbating seagull". --JWSchmidt 01:42, 31 July 2006 (UTC)

There's over 55000 for seagull + masturbation though. Hyenaste ^(tell) 01:45, 31 July 2006 (UTC)

Can Seagulls Masturbate?

Can Seagulls Masturbate? The answer is 42.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

In small arms ballistics, how is "effective range" defined?

What does it mean for a rifle to have an effective range of 400m? Obviously a rifle bullet carries a dangerous amount of kinetic energy way beyond its effective range. And the probability that a target at a given range is hit in a single shot depends on many factors (e.g. marksmanship of the shooter, power of the scope, weather, size of the target). So, is there a standard definition for "effective range"?

It apparently depends on who is giving the value; it is not standardized. See this article on it, which I found by Googling "maximum effect range definition". --Fastfission 18:02, 30 July 2006 (UTC)

Would also depend on the effect you're after, I'd say. DirkvdM 09:18, 31 July 2006 (UTC)

in military terms, the effective range couples both the stopping power of the round, the velocity at that distance and the chance of hitting a target at that range. for example, in the NZDF, the effective range of the Steyr AUG was quoted as 300m, while that of the c9 lsw (a version of the FN Minimi) was quoted as much further, off the top of my head at least 600m. yet both fire the same round (5.56mm ss-109), but the c9 in normal use pumps out more rounds. Xcomradex 11:12, 31 July 2006 (UTC)

Railroads: Where are the breaks on a freight car?

In the past the breaking force and break shoes on a railroad freight car were applied to the wheel rim to slow or stop the car. I don't see that on today's (USA)rail freight cars. Where is the breaking force applied and what's the mechanism that stops the wheel from rotating?

The, um, BRAKES on a railroad freight car are part of the truck assembly. This document has a really nice exploded diagram of a railcar truck on the third page. The brake shoe contacts the tread of the steel wheel. There is one shoe per wheel, four per truck.

tread??

Hall Effect

cant we use hall effect in producing electricity ? high voltage supply cables on their way could b made 2 pass through tubes containing magnetic field.hence by hall effect potential difference would exist. but i doubt the high voltage cable would get weaker in voltage after passing through the tube. plz if anyone can explain it relating to conservation of energy and other phenomenons involved

---

Legend:

  1. Electrons (not conventional current!)
  2. Hall element, or Hall sensor
  3. Magnets
  4. Magnetic field
  5. Power source

In drawing "A", the Hall element takes on a negative charge at the top edge (symbolised by the blue color) and positive at the lower edge (red color). In "B" and "C", either the electric current or the magnetic field is reversed, causing the polarization to reverse. Reversing both current and magnetic field (drawing "D") causes the Hall element to again assume a negative charge at the upper edge.

I would suggest checking the article too. Hall effect

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

---

Since a violation of the law of conservation of energy isn't possible (unless mass was converted into energy, which doesn't happen here), the energy passing thru the tube must be reduced to a level to match any increase outside the tube. StuRat 01:12, 31 July 2006 (UTC)

Fear of losing possessions?

What is a correct -phobia term for fear of losing possessions (assuming that one is NOT afraid forgetting, meaning it's not Athazagoraphobia). Bayerischermann 19:43, 30 July 2006 (UTC)

There's a list of phobias. Have you checked there?--Frenchman113 on wheels! 22:01, 30 July 2006 (UTC)

Help

The tornado section does not have the "three categories of tornadoes."

I am asked this by several people who dont know the awnser so I come here to Know the awnser and it is not here.

Please help!!!!! --Qho·^(talk)·_(contribs) 20:26, 30 July 2006 (UTC)

What three categories of tornados? I am not aware.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Do you mean shape? There is funnel (think triangle), wedge (think fat kind), and multi-vortex. If so, that's in the article.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Possibly there is some confusion with the Fujita scale or even the Saffir-Simpson Hurricane Scale? Melchoir 21:02, 30 July 2006 (UTC)

regulation of psychotherapy

When did the state of New Jersey started regulating psychotherapy? I found this online:1945 "The state of Connecticut passed licensure legislation for psychologists, becoming the first state to recognize psychology as a protected practice oriented profession." (source).
--JWSchmidt 04:40, 31 July 2006 (UTC)

Looks like it was around 1968. .pdf file of New Jersey law - Nunh-huh 04:51, 31 July 2006 (UTC)

Thanks. Is it safe to assume that before ~1968 the New Jersey State Board of Medical Examiners would have been involved in State regulation of psychologists and anyone practicing psychotherapy or was psychotherapy basically not regulated by the State? --JWSchmidt 05:06, 31 July 2006 (UTC)

I don't think the Board of Medical Examiners played any role, as the practice of psychotherapy seems to have been unregulated before that time. The NJBME would have (still does) regulated psychiatrists, of course, but that was the practice of medicine. - Nunh-huh 05:25, 31 July 2006 (UTC)

Wikipedia articles about scientology heavily cite the website of Operation Clambake. One page at their website says, "In 1951, the New Jersey State Board of Medical Examiners filed charges against HDRF for teaching a branch of medicine without a license". I'm trying to figure out if this makes sense. The idea that a "Board of Medical Examiners filed charges" seems odd. --JWSchmidt 06:11, 31 July 2006 (UTC)

The NJSBME certainly brings charges against those who practice medicine without a license. They list the names of those deemed guilty monthly. "Filed" wouldn't be my verb choice, but it's pretty much synonymous. - Nunh-huh 06:28, 31 July 2006 (UTC)

Thanks for all of your help. This is starting to make sense. I found this which suggests that the attorney general brought the case to court. --JWSchmidt 06:41, 31 July 2006 (UTC)

No problem. Perhaps the board only handles civil penalties, and the attorney general handles cases referred from the Board for criminal prosecution. - Nunh-huh 06:44, 31 July 2006 (UTC)

Name for a class of chemical reactions

Is there a general name for a reaction in which a large molecule is split by the addition of a small molecule? It's the reverse of condensation, and hydrolysis is a special case. Solvolysis isn't it because the small molecule that's added isn't necessarily the solvent. Any ideas? —Keenan Pepper 07:01, 31 July 2006 (UTC)

"cleavage" is used a bit in the literature, i can't think of anything more scientific, but i might be forgetting something obvious. Xcomradex 11:14, 31 July 2006 (UTC)

I like cleavage.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

In nuclear reactions, a large nucleus is split into two smaller atoms by collision with a small nucleus (or neutron). This is called nuclear fission but I doubt it is what you are looking for. Perhaps, decomposition? Nimur 16:37, 31 July 2006 (UTC)

black hole and parital black body

s black hole a partial black body?? if no please explain how--59.178.4.239 09:26, 31 July 2006 (UTC)

No. A blackbody (usually written as one word) is an object which reflects absolutely no electromagnetic radiation that falls on it. A black hole is a perfect blackbody.

Unless you believe in Hawking radiation.... TenOfAllTrades(talk) 13:10, 31 July 2006 (UTC)

Hawking radiation is emitted from (as opposed to reflected by) black holes. Blackbodies may emit radiation (stars are almost perfect blackbodies) they just don't reflect any.

Physics - alfoil

Why doesn't aluminium foil get hot in the oven? I know it is an insulator and effective in reflecting heat, but why? Would other metals (say copper) have a similar effect? BenC7 09:51, 31 July 2006 (UTC)

It does get hot, but because it is so thin and has a large surface area compared to its mass, it loses most of its heat almost as soon as it comes out of the oven.--Shantavira 09:58, 31 July 2006 (UTC)

It is important to note the difference between Temperature and Heat. Though the temperature may rise, there is not much heat energy stored in the foil because it is so low-mass. Also, although it reflects heat, I believe Aluminum would usually be classified as a conductor. This has a double-effect: the heat is easily conducted away whether it is warming up or cooling off! Nimur 16:35, 31 July 2006 (UTC)

I'll note in response to Nimur's comment that while aluminum is a pretty good conductor of heat, it does an excellent job of blocking radiant heat (infrared radiation). Also, since the foil traps the air around the wrapped-up food, it reduces the convective cooling. TenOfAllTrades(talk) 17:48, 31 July 2006 (UTC)

Well spoken, Ten. Maybe we should link to Convection, Conduction, and Radiation - which are the three mechanisms of heat transfer. Understanding the interplay between these will help the original questioner get a sense of the way food actually gets warm inside an oven. Nimur 20:46, 31 July 2006 (UTC)

Acceleration/Deceleration

I began thinking about this while driving down the road one day. Say I'm accelerating at a rate of 5 mph/sec and I come to a hill which drops my rate of acceleration to 2 mph/sec. While my rate of acceleration is decreasing, am I decelerating or still accelerating? Or both?

I suppose that you mean to say that you are travelling at a velocity of 5 mph and when you encouner a hill, your velocity drops to 2 mph. That means that you have decelerated. If your velocity is still decreasing while you are climbing uphill, then you are still decelerating. We can say that the deceleration is constant if the rate of decrease in velocity is constant (say the velocity drops by 1 mph every second).

If this is not the answer you are looking for, you may need to reframe the question.--Wikicheng 13:02, 31 July 2006 (UTC)

You are still accelerating because your acceleration is still greater than 0. You just accelerate more slowly when you are on the hill. --Yanwen 13:56, 31 July 2006 (UTC)

Yanwen is right. Your rate of acceleration is decreasing, but your velocity is still increasing. As an aside, as you get to the hill, and your rate of acceleration drops, your jerk is decreasing - jerk is another word for "rate of acceleration". All these quantities should become blissfully clear if you take a basic calculus course - all these quantities are different derivatives of your position. Your position is the "zeroth" derivative of position, your velocity is the first derivative of position, acceleration is the second derivative of position, jerk is the third, etc. And consequently acceleration is the first derivative of velocity, and jerk is the second, etc etc. --Bmk 14:39, 31 July 2006 (UTC)

sun

What is the most visible part of the sun? a)Corona, b)Chromosphere, c)photosphere, d) prominence

If you read our article on the sun (<== click on the link), you will quickly find out that the most visible part of the sun is the....aack! (*#&$#@$#( Gasp.... the gods of the reference desk are smiting me for almost answering a homework question! I'm sure you'll find the answer pretty quickly. (PS: I would suggest using your browser's text search function and search for "visible" once you get to the sun article) --Bmk 14:49, 31 July 2006 (UTC)

This does sound rather like a homework question. The answer should be pretty obvious if you paid attention to the different layers of the Sun.

The outside part? --Ginkgo100 ^{talk · contribs · e@} 14:56, 31 July 2006 (UTC)

The shiny bits. – ClockworkSoul 20:05, 31 July 2006 (UTC)

star

Is the North Star the major reference point in the celestial sphere?

Depends where you live. Not in Australia. Notinasnaid 15:14, 31 July 2006 (UTC)

Yup. See North Star and Pole Star.--Shantavira 15:25, 31 July 2006 (UTC)

The North Star is Polaris.

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

Sulfuric Acid

I'm confused. You say that both Jabir ibn Hayya and al-Razi discovered sulfuric acid. Which one was it?

I'm not sure who "you" is, but the wikipedia article on Sulfuric Acid states that Jabir ibn Hayyan is credited with the discovery, but al-Razi studied its properties and production. I don't see a contradiction - hope that clears things up. And btw, it's usually helpful to link to articles that you are referring to so everyone knows what you mean - do this by enclosing an article name in double square brackets. --Bmk 15:41, 31 July 2006 (UTC)

Quoting from the article on al-Razi: "Razi is credited with the discovery of sulfuric acid". --Lambiam^Talk 17:27, 31 July 2006 (UTC)

Ah - thanks. That seems like a difficult contradiction to resolve - probably will take someone more familiar with the topic and the sources. There may be no good answer, but the articles should at least agree with each other. --Bmk 17:38, 31 July 2006 (UTC)

Intersexual or Hermaphrodite?

What is the correct term for a person who is neither male nor female? One one hand, Wikipedia's articles state that "hermaphrodite" and "pseudo-hermaphrodite" are antiquated and offensive, and have been replaced by "intersexual." On the other hand, I have seen numerous uses of these words in the media. Including the article by Jared Diamond in Discover magazine. JianLi 16:13, 31 July 2006 (UTC)

Hermaphrodite would mean both male and female, neither would be asexual. Hermaphrodite is only somewhat offensive to humans, but the term is used in biology all the time. I have never heard intersexual. Is that like transexual?

1.  Task complete. You're welcome! Huggums^{537_voted! (sign🖋️|📞talk)} 21:36, 14 March 2025 (UTC)

According to the relevant articles, asexuality refers to the condition of having no sexual interests or desires, while intersexuality describes the condition of having ambiguous genitalia. The latter sounds like what the questioner was asking. Intersexuality notes that advocates for intersexual people do not like the terms hermaphrodite and pseudohermaphrodite, which suggests they should be restricted to describing non-human animals. --Ginkgo100 ^{talk · contribs · e@} 21:25, 31 July 2006 (UTC)

Digital cameras and battery life?

I'm considering buying myself a new digital camera, as my old one seems to have finally died on me. Quick question - are the newer ones still as battery-hungry? My previous camera (bought about seven years ago) would go through 4xAA batteries in a couple of hours, less with rechargables - I hardly ever used it because it was so damn impractical. --Kurt Shaped Box 18:40, 31 July 2006 (UTC)

I don't know about cameras being less power hungry, but in my experience modern NiMH rechargeables should easily outlast ordinary disposable AA cells. Mind you, the highest-capacity ones tend to be costly, and the capacity ratings are usually "ideal" ones: a "2400 mAh" battery does not usually last 1.5 times as long as a "1600 mAh" one in practice, and will usually cost more than 1.5 times as much. Still, even the low-end ones often outperform disposable cells in camera use, since they deliver a more stable voltage over time. A good battery charger is also important — it doesn't have to be an expensive brand-name one, but it should be ΔV-controlled ("intelligent") and should have independent charging circuits for each cell. I've had good personal experiences with the cheap store-branded "Rapid Charger" and cells from Biltema; similar products, or possibly even the exact same ones modulo branding, can probably be found in local stores elsewhere. —Ilmari Karonen (talk) 19:36, 31 July 2006 (UTC)

I have a German brand, Concord 5345z (5 Megapixels), which comes with a recharger for it's two rechargeable AA Nickel-Metal Hydride batteries. I would call it a battery hog, yes, as the two batteries only last about a day if you are taking pics constantly. However, as long as I remember to recharge them every night, a one day charge seems workable. One bad side, though, is that uploading the pics to my laptop also depletes the charge. I've learned not to dawdle when doing so. I used to upload one pic, then edit it, then do the next, etc., which ran my batteries down. If I just upload them all at once, then turn off my camera and recharge the batteries while I edit the pics, it works out much better. StuRat 22:37, 31 July 2006 (UTC)

Reflection and Radiation mutually exclusive?

Lets say I take a shiny metal object, one that is polished and reflects light well, and heat it until it glows red-hot. Does the object continue to reflect light while it is glowing, (I assume the intensity of the radiated light would be many times greater than that of the reflected light, obscuring the latter), or are radiation and reflection mutually exclusive behaviors? Assume that the shiny metal is heated in an oxygen-poor environtment to avoid tarnishing oxidation. I was unable to find the answer in blackbody or associated articles.Tuckerekcut 19:03, 31 July 2006 (UTC)

Yes, it will continue to reflect light. And if you could build a precise-enough instrument to measure the intensity of light, (or any other part of the EM spectrum), you would be able to see that the two processes add linearly. Nimur 20:47, 31 July 2006 (UTC)

Actually, this isn't really correct. If the object is hot enough to be visibly glowing, then the spectrum of excitations responsible for that glow will also make it receptive to absorbing visible light, at which point the light shined on to it would be partially contributing to heating the object. Since energy must be conserved, the total emitted light would still be expected to vary linearly with the light shined on it (neglecting other modes of energy dissipation), but the spectrum would be changed and not have the wavelength preserving qualities normally associated with reflections. Dragons flight 21:43, 31 July 2006 (UTC)

String Theory as a T.O.E.

Hello. How does string theory solve the renormalization problem of gravity? And if it doesn't, why is it considered a possible T.O.E?AmateurThinker 22:48, 31 July 2006 (UTC)