Wikipedia:Reference desk/Archives/Science/2006 June 7

Humanities Science Mathematics Computing/IT Language Miscellaneous Archives

The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions at one of the pages linked to above.

< June 6 Science desk archive June 8 >

spinal meningitis: asprin? or not?

My roommate was exposed to a woman who had taken care of her mother who was diagnosed with spinal meningitis... she has since fell ill and in complaining of a stiff neck, she has a high fever and is sleepy a lot more than usual fatigue... she took some asprin today and i am concerned that that was not a good idea. Is taking asprin a problem for suffers of spinal meningitis? I know she should seek medical treatment as soon as possible but I want to know of extreme dangers with taking asprin. Thank you! -- Joann

Warning, many people here consider writing in all uppercase to be a capital offence. StuRat 03:03, 7 June 2006 (UTC)

I have turned your question into one that follows the guidelines listed at the top of the page, and all your phone numbers and email addresses have been removed for privacy. I encourage you to read about them at meningitis, and asprin. Asprin is probably good for her! The symptoms sound a lot like meningitis. I hope she gets well soon! — The Mac Davis] ⌇☢ ญƛ. 02:52, 7 June 2006 (UTC)

The problem would seem to be that she has reason to believe she has meningitis and has not immediately gone to an emergency room. That choice means that she might die. Prompt diagnosis - a matter of hours - makes the difference between survival and death. The aspirin will certainly be a problem if she's substituting it for prompt diagnosis and treatment of what may be a fatal illness. - Nunh-huh 03:20, 7 June 2006 (UTC)

• Taking aspirin when you have meningitis is shouldn't hurt you, but please-please have them see a doctor. - Mgm|^(talk) 07:42, 7 June 2006 (UTC)
• Not only that, but anyone who has been exposed should see a doctor and get antibiotics to prevent spread. InvictaHOG 04:00, 14 June 2006 (UTC)

If the sun turns off, when does the earth freeze?

If the sun was to be extinguished how long would it take for the landmass of the earth to be too frozen for human life

Just a few days, I would think. After all, the temps drop by something like 2 degrees an hour on average at night. That would be 48 degrees a day, or close to 200 degrees lower than the starting temp in 4 days. That would be enough for you to feel Jack Frost nipping at your... StuRat 02:50, 7 June 2006 (UTC)

lol, we don't know. It takes light from the sun like four minutes to get to Earth? I forget. Maybe its nine. — The Mac Davis] ⌇☢ ญƛ. 02:52, 7 June 2006 (UTC)

It's eight and a half minutes, but that's irrelevant, or we would all die every time there's an eclipse, LOL. StuRat 03:01, 7 June 2006 (UTC)

You're assuming a linear time dependence, when it would probably be closer to exponential decay (see Newton's law of cooling). We could use the data you give about the cooling rate at night though to figure out the relaxation time of the exponential. I expect the rate would be higher with no sun than it would at night, for obvious reasons. -lethe ^{talk +} 03:39, 7 June 2006 (UTC)

You mean me? All I said was the time it takes from light from the sun to get to the Earth. What what do you mean Stu about dying everytime there is an eclipse? I didn't say anything like that either. — The Mac Davis] ⌇☢ ญƛ. 03:52, 7 June 2006 (UTC)

Nope, I mean StuRat. StuRat is assuming a linear fit. And what StuRat means about dying every time there's an eclipse is this: you mention that it takes 8 minutes for light from the sun to reach the Earth. The implication of your statement is that when the light stops is when the heat will stop. If that were true, we would freeze every night and every eclipse. Of course, it is true to some extent. Temperature does fall every night and every eclipse. It's true that if the Sun disappeared, we would not start cooling off until 8 minutes later. Nevertheless, those 8 minutes are fairly negligible next to the time the cooling takes, which is on the order of a couple days. -lethe ^{talk +} 04:02, 7 June 2006 (UTC)

Yes, that's exactly what I meant. StuRat 17:59, 7 June 2006 (UTC)

As for StuRat's 48 degrees a day, I would assume quite a bit higher. Sunlight has a considerable effect on the temperature of the dark side, basically because the atmosphere permits circulation of the warm air. If the sun turned off, the only thing heating the earth would be the core, but I don't think that would do much to slow down freezing, and even the core wouldn't last too long, without all the electric activity coming from the sun.  freshofftheufoΓΛĿЌ  04:50, 7 June 2006 (UTC)

I would think circulation of water would continue until the surface of the oceans froze solid (circulation would continue beneath the surface until the oceans froze solid, if ever, but this would not have much effect on the atmospheric temp). The atmosphere would also continue to circulate until the temps were equal everywhere. However, this circulation would provide no net warming of the Earth's surface, but would only equalize the temps. I suspect the temp drop would start out a bit higher than 48 degrees a day, but then reduce as the temps approached the equilibrium surface temp, which would still be considerably above absolute zero due to nuclear radiation from the Earth's core and gravitational tides from the Moon and Sun (if it still exists even though no longer putting out any light). StuRat 17:59, 7 June 2006 (UTC)

Right, well I guess it depends what temperature you assume the planet would achieve equilibrium at. Without any figures or evidence to back me up, I have a hunch that the temperature drop wouldn't slow down very much until after reaching freezing. I'm so bold!  freshofftheufoΓΛĿЌ  06:41, 8 June 2006 (UTC)

I agree, and this is why the simple version of my answer was that it will drop approximately linearly, at around 50 degrees a day, for the first few days, by which time we would all be dead and no longer care if the rate is linear or not. StuRat 19:39, 8 June 2006 (UTC)

Are you suggesting that the Earth's core is powered by electricity from the Sun? That sounds preposterous for a number of reasons. -lethe ^{talk +} 06:17, 7 June 2006 (UTC)

I didn't mean to imply just that, though I admit I might be mistaken. I was under the impression that the electromagnetic radiation from the sun had some effect on the earth's magnetic field, which then in turn influenced the motions of the metals in the earth's core.  freshofftheufoΓΛĿЌ  06:59, 7 June 2006 (UTC)

I don't think that's true. The only thing I can say about the Sun and the Earth's magnetic field is that the Aurora Borealis comprises matter from the Sun (and other cosmic radiation) caught in the Earth's magnetic field. But the field arises from the rotation of the iron core, which is just leftover angular momentum from when the planet formed. -lethe ^{talk +} 07:03, 7 June 2006 (UTC)

However, wouldn't most (all) of the energy (heat) loss be through electromagnetic radiation, so the Earth would cool down at something proportionate to its temperature to the 4th? --Borbrav 06:48, 7 June 2006 (UTC)

I suspect lack of solar radiation would cool the core. Without sunlight the atmosphere & surface would cool increasing the heat loss from the core. But I suspect humans would improvize and survive without much dificulty. XM 16:15, 7 June 2006 (UTC)

Well, not if the temps dropped worldwide to hundreds of degrees below zero in under a week, there would be no time to adjust. Even if there were years to prepare, only a few wealthy nations could set up the nuclear reactors needed to provide the heat necessary for survival. StuRat 17:59, 7 June 2006 (UTC)

As for the Earth's core cooling due to a lack of sunlight, I would expect it to cool somewhat, but when this caused the layer of solid crust to become much thicker, say 3000 miles thick, this would prevent cooling by convection, volcanoes, plate tectonics, geysers, etc., and the small amount of heat produced by the nuclear radiation and tidal forces would then be retained in the Earth's core. However, for the same reason, very little of this heat would reach the surface. StuRat 18:52, 7 June 2006 (UTC)

An eclipse would not have the same effect as the sun extinguishing, an eclipse only completely covers a very small area, and there are large areas that are not even marginally covered. Philc _T^E_C^I 18:00, 7 June 2006 (UTC)

Well, that's true, but even if the Sun completely stopped shining on the Earth entirely for the duration of an eclipse, the effect would still be minimal. So, in that way, both have the same effect (very little) on the Earth's temp. StuRat 18:52, 7 June 2006 (UTC)

Fair enough, what temperature would the earth drop to, considering its nice warm molten core, and if the surface became uninhabitable could we just dig down and live underground closer to the mantle. Philc _T^E_C^I 21:04, 7 June 2006 (UTC)

I would think the surface temp would eventually drop to maybe tens of degrees above absolute zero, although this would take millions or even billions of years, as it would depend on the Earth's mantle cooling first, leaving only the core molten. Since the mantle is a huge temperature sink, and is somewhat well insulated by the current thin crust, and will eventually be well insulated by an extremely thick crust, this will take a while. Moving down to where it's warm would require digging holes thousands of miles deep, no easy task. I would think we would want to move underground, but just far enough to benefit from the insulation effect, perhaps a few hundred feet. Thus, our heating needs could be met by a modest energy source, say a nuclear reactor. The food supply would need to be grown hydroponically, using the same energy source. We would need to recycle all our water and air or get frozen water and liquid air from the surface. I suppose any unrecycleable waste would just be piled up on the surface, where it would stay frozen forever. It would be really ugly, but nobody would be on the surface to complain. StuRat 19:39, 8 June 2006 (UTC)

Why would the core cool so dramarically, considering only a tiny amount of the energy the keeps it warm is provided by the sun. Philc _T^E_C^I 15:30, 13 June 2006 (UTC)

Well, only a tiny amount of the heat is produced by radiation and tidal forces, too. There is very little heating of the Earth's core going on, it's just very well insulated so that any small amount accumulates over time. Remove the Sun and it would start to dissipate over time, until it got to a considerably lower temp. StuRat 04:25, 14 June 2006 (UTC)

I have serious doubts about whether the human race would survive such an event. Well, it's obvious that the 6 billion of us wouldn't all survive. But would a couple thousand survive at least? I am dubious, but I guess it's possible. -lethe ^{talk +} 04:50, 8 June 2006 (UTC)

Given enough time, I would think preparations could be made for many people, perhaps millions, to survive. However, I doubt if any current underground location exists with a water supply, food supply, air supply, energy supply, and sewage system which aren't at least partially dependent on the surface, in the long run. Given only a few days, there wouldn't be time to build such a system, either. People might hide out in deep mines and bomb shelters for a while, but once the supplies expired, so would they. StuRat 19:56, 8 June 2006 (UTC)

How is the Sun being extinguished? If you simply stop the nuclear reactions, the Sun will still be very hot and still radiating black body radiation. The Sun will start to cool, but it could be a long time before Earth is actually affected. Peter Grey 04:05, 9 June 2006 (UTC)

Okay let me revamp, if for a reason unknown to us the Sun suddenly became completely extinguished giving off no radiation in any shape or form, how long would it take for the surface of the earth to becone too could to support human life as it is now, as a starting point I understand (and dont hesitate to correct me if I am wrong)it takes eight minutes for radiation in the form of light to reach Earth from the Sun. Sorry for not signing my name originally60.234.132.130 03:21, 14 June 2006 (UTC) Hatch

As I said, a few days. Specifically, I would expect the majority of the human race to be dead by the end of a week. StuRat 04:25, 14 June 2006 (UTC)

Chemistry - crystallisation

hello..

i'm Dianne and I just want to know what would happen if the crystals are dried over the bunsen flame?

             250 degrees Celsius
   CuSo4.5H20 -------------> CuSo4 copper (II) sulphate
 blue crystals               white powder

Since the temperature of the bunsen flame is higher , what would happen?

thanks a lot!!

--219.75.102.245 03:27, 7 June 2006 (UTC)

Hello, I am Mac! When heated in an open flame copper sulfate crystals are dehydrated and turn grayish-white. If you burn them, the copper ions are responsible for a blue tint. Fireworks that are blue have copper in them. Check the Copper(II) sulfate article first next time. This is an encyclopedia after all. — The Mac Davis] ⌇☢ ญƛ. 04:03, 7 June 2006 (UTC)

Hydrogen supplement devices for gasoline engines

I've found a couple interesting links to devices that are installed on automobiles, and make use of electricity from the auto's electrical system to separate water into gaseous oxygen and hydrogen, which is then introduced into the intake manifold. Claims of better fuel efficiency and decreased pollution are made for vehicles which have these devices. Are these claims sensible, or are these devices like the infamous "200 mpg carburetor" that the auto industry is supposedly keeping secret?

I don't know anything about cars, but based on what I know about physics, it sure sounds possible, and it would be an award winning science fair project on the order of the Intel Science and Engineering Fair. The separation of water into oxygen and hydrogen theoretically used is through the process of electrolysis, and it indeed uses electricity. There would probably be less pollution if burning hydrogen and oxygen worked along with gasoline well, because hydrogen and oxygen are totally clean burners. However, more pollution is created this way most likely, because of the production, use, and dispensing of the car's lead acid batteries. — The Mac Davis] ⌇☢ ญƛ. 04:09, 7 June 2006 (UTC)

Uh? So you'd be burning some gasoline to power the electrolytic apparatus, which will then produce some hydrogen, which is added to the air intake to be combusted, thus reducing overall gasoline consumption? Sounds rather perpetual-energyish to me, unless you can actually get more energy by using X amount of gasoline to electrolyse water and then burning the H2, as opposed to just burning the gasoline?--inks^T 04:16, 7 June 2006 (UTC)

No, silly! You're using the car battery to power the electrolytic apparatus, which produces hydrogen which is added to the air intake to be combusted, thus reducing overall gasoline consumption. — The Mac Davis] ⌇☢ ญƛ. 04:37, 7 June 2006 (UTC)

And what recharges the car battery?--inks^T 04:42, 7 June 2006 (UTC)

Nothing, like I said in my first response to the questioner, however, more pollution is created this way most likely, because of the production, use, and dispensing of the car's lead acid batteries — The Mac Davis] ⌇☢ ญƛ. 04:50, 7 June 2006 (UTC)

There's a problem here. The alternator is constantly recharging the car's battery; the engine, of course, burns fuel in order to power the alternator via a spinning belt. Bloodshedder 17:28, 7 June 2006 (UTC)

Have I missed a Very Subtle™ bit of sarcasm? :D --inks^T 04:53, 7 June 2006 (UTC)

The hydrogen-oxygen mix is supposed to make the petrol-oxygen mix burn with higher efficiency, enough to more than compensate for the energy used in electrolysis. (I think it works because hydrogen will burn in anything, taking the petrol with it; this allows the burn to be leaner, so the expansion phase is more efficient. Also, it produces water in the exhaust, giving the expansion phase more power.) Obviously, the fuel ratio and timing settings need adjusting. Any gain is going to be pretty marginal. -- EdC

Water is also produced as a result of gasoline combustion, and, in fact, most hydrocarbon combustion. StuRat 17:38, 7 June 2006 (UTC)

This sounds like Brown's gas, an article about a pseudoscience that seems beset by anon pseudos. -- Finlay McWalter | Talk 21:51, 7 June 2006 (UTC)

Yes, Brown's Gas was mentioned on a couple of the websites I found when looking up hydrogen supplement devices (I posted the original question). I would agree that the whole concept sounds too "perpetual-motion"-ish to be believable, coupled with the near irresistible lure of better gas mileage now that gas out here is about $3.20/gallon.

What I can't reason out is if there's any net energy gain, or if the various losses in the systems involved negate the increased combustion energy. I was told by one of the proponents of this idea that "it takes very little energy to liberate the hydrogen and oxygen from water". That being said, aren't chemical reactions reversible and wouldn't the energy change be equal? So the energy released in (added to) the combustion chamber would be about equal to the energy it took to generate the Brown's gas. Which means the auto's engine had to drive the alternator a little harder to create the power to make the hydrogen, which would negate any net benefit...? Right?

The energy created by burning hydrogen in oxygen is exactly equal to the energy required to separate the two, assuming 100% efficiency. However, there will always be some inefficiency, such as excess heat given off into the atmosphere. So, in reality, performing any type of reversible chemical reaction both ways will cost energy. Now, if hydrogen gas is really a wonderful catalysts for gasoline combustion, then that might offset this energy loss. However, I am skeptical regarding this part of the claim. StuRat 20:05, 8 June 2006 (UTC)

Home-made infrared filters

According to the Wikipedia infrared filter article: "There have been several reports that using exposed and developed film works as an infrared filter. The theory is that the film goes jet-black thus blocking visible light but allowing infrared to pass."

Oh come on! Only "several reports"? Shouldn't it be easy to test this sort of thing?

Anyways, I decided to take out 3 film negatives, and use them as a filter for my digital camera. They seem to work. For example, here is a photo of a tree (and here is the full-sized version).

My question is: why have there only been "several reports" that film negatives work as infrared filters? --Bowlhover 04:09, 7 June 2006 (UTC)

CCDs in the digital camera only see red, green, and blue light, don't they? A few days ago somebody asked a question regarding the night vision goggles article's external link showing that being done. They asked if it was possible, and why. — The Mac Davis] ⌇☢ ญƛ. 04:19, 7 June 2006 (UTC)

Actually, most CCDs are sensitive to infrared light. (See Charge-coupled device#Applications.) Digital cameras have a mirror that reflects the IR but lets visible light through, but no mirror is perfect.

To show that my Canon Powershot A620's CCD is sensitive to IR, here is a picture of a remote control, clearly showing the two infrared bulbs. (Here is the full-sized version.) --Bowlhover 04:44, 7 June 2006 (UTC)

More expensive cameras like yours have night settings that use IR and produce green pictures, but most cheap cameras do not feature this. — The Mac Davis] ⌇☢ ญƛ. 05:31, 7 June 2006 (UTC)

Wow, nice pictures. I am so doing these things. — The Mac Davis] ⌇☢ ญƛ. 04:33, 7 June 2006 (UTC)

The "weasel words" were probably used because either a) it hasn't been universally accepted that the result actually shows infrared imaging or b) it's a simple case of weakly disguised original research. Judging by the images you provided, they don't seem to help much in filtering out infrared light, though the properties of the pigment in the grass and the leaves seem to make them stand out considerably. I'd expect the cars to show some evidence of infrared, though as they are it simply looks like an oddly contrasted B&W photo.

Sorry, I edited my comment a little bit before I saw yours. — The Mac Davis] ⌇☢ ญƛ. 04:41, 7 June 2006 (UTC)

The original quote says "exposed and developed film", so I assume there's some way to prepare the film so that it completely blocks out all light apart from infrared, and even then, as Mac said, a normal camera (using normal film) probably wouldn't show any difference even with the filter in place, for the simple reason that commercial cameras aren't sensitive to infrared light. It seems to me that using a film that has been completely blacked out (to visible light) as a filter in a camera sensitive to infrared light frequencies should work, assuming you have such a camera. The filter would just serve to cut out the un-needed visible frequencies of light.  freshofftheufoΓΛĿЌ  04:35, 7 June 2006 (UTC)

I'll take your word on those new prints. I don't know much (or anything) about CCDs : (. I can't really think why the lights would appear purple though...  freshofftheufoΓΛĿЌ  04:54, 7 June 2006 (UTC)

Well, infrared rays don't have any colour (because we can't see them), so the purple colour is entirely because of the white balance. If, after I put the filter over the lens, I set the white balance to "manual" and let the camera assess what it should be, I will get a black-and-white photo (like the photo of the tree that I posted).

Anyways, to show that film negatives do work as an infrared filter, here are three photos of my remote control:

1. http://72.136.70.187/remote_control/remote1.JPG (full version)
2. http://72.136.70.187/remote_control/remote2.JPG (this is the full version)
3. http://72.136.70.187/remote_control/remote3.JPG (full version)

All 3 photos were taken within 2 minutes of each other. They were taken using the same camera and with the exact same camera settings (I set my camera's shooting mode to "manual"). My 3 film negatives were only used as an IR filter in the second photo.

By the way, Mac Davis, why do you expect the cars to show evidence of infrared? --Bowlhover 05:23, 7 June 2006 (UTC)

What about cars? Nice remote, it is the same model as mine. :) — The Mac Davis] ⌇☢ ญƛ. 05:45, 7 June 2006 (UTC)

Actually I made the comment about the cars. I expected the most likely source of infrared light from the first picture would be the trees and the cars (assuming they were somewhat warm), and possibly the windows from the house. I'm still confused about the purple though... even if the camera white-balanced the color settings, purple is on the opposite end of the light spectrum. I would expect the camera to shift the infrared light into the visible red spectrum, unless it got really confused.  freshofftheufoΓΛĿЌ  06:53, 7 June 2006 (UTC)

The wavelengths of infrared rays spans a million nanometres, from 700 nm to 1 million nm. (For comparison, all the colours of the rainbow are cramped into 300 nm). The infrared emitted by warm objects is black body radiation. The wavelength at which black body radiation has the strongest intensity (we'll call it the peak wavelength) depends on the temperature of the object: as the temperature increases, the peak wavelength gets shorter, and vice versa.

Thermal imaging is done with infrared rays which have a wavelength of 900 nm to 14 000 nm. This corresponds to a black body temperature of 2950 degrees Celsius (for 900 nm) to -66 degrees Celsius (for 14 000 nm). Black body radiation emitted by a human has a peak wavelength of 9343 nm. However, according to our infrared filter article, exposed & developed film starts transmission at 710-730 nm. 730 nm corresponds to a temperature of 3696 degrees Celsius--far hotter than any cars or houses. Even if my camera's CCD sensor can detect wavelengths as long as 9300 nm (which I doubt), IR emitted by the Sun completely overwhelms what little black body radiation houses/cars/trees emit. As with normal photography, the IR photography I do mostly involves reflected radiation, not emitted radiation.

As for why the infrared bulb on my remote control appears violet, I admit I don't really know. But according to the graph halfway down the page at [1] (also read the paragraph before it), the red, green, and blue filters in the Bayer filter mosiac will begin allowing more infrared to pass at longer wavelengths. At around 840 nm, all three filters will admit approximately the same amount of infrared. Mixing red, green, and blue produces white, so the camera will get confused and think that 840-nm radiation is the colour white. If the camera thinks that an object is white, then the colour of the object in the final image depends entirely on the white balance. --Bowlhover 04:35, 8 June 2006 (UTC)

The top of this image [2] shows the spectral response of an unmodified digital camera, below is the response of the IR modified camera. This image was taken using a CD as a diffraction grating and a tungsten bulb as the light source. Thought the method was not very scientific and the accuracy may be suspect, it gives some indication of the efficency of film as an IR filter. From [3] — The Mac Davis] ⌇☢ ญƛ. 07:42, 7 June 2006 (UTC)

Appreciate the explanations. Now I must admit that that's pretty damn cool. Infrared webcam! And as for the original question: why several reports? Someone being too cautious I guess. Find one good source and it should be easy to make that statement more concrete.  freshofftheufoΓΛĿЌ  06:28, 8 June 2006 (UTC)

Nuclear weapon question

OK, I'm writing a science fiction story. It takes place after an apocalypse level event, so most of the human population is gone, and it's in Australia.

My characters need a nuke to destroy a rival settlement. I figured I could just have them retrieve one from an American warship that was in the country at the time. The crew would be dead, and I'm pretty sure American fighter jets and even the ship itself would have nuclear missiles in them with tasty retrievable warheads.

However, I also need for them to have a codebook of some kind to set off the nuke (or an access key, or something. It's a MacGuffin. I just need something small that is neccesary to use the nuke). And I'm fairly certain nuclear warheads in fighter jet missiles don't have codebooks, they just get shot out at high speed and go off from the impact.

So if there was no codebook, and they just cut a nuclear warhead out of a missile and lugged it away... how would they set it off? Drop it out of a plan? Take the Glen Bateman (The Stand) way and just pack dynamite around it?

Help me out here! This kind of stuff is very hard to research because it's generally classified as a military secret.

I bet your characters (describe them?) would probably just set a timed explosion, with C4 and blaster caps. Find an interesting way they could make a makeshift fuse for timed detonation. — The Mac Davis] ⌇☢ ญƛ. 04:54, 7 June 2006 (UTC)

Well, the arming and triggering device depends on what type of nuclear weapon it is! :D You can't just drop it from a height and expect it to go off, nor can you just randomly pack explosives around it. Have you read Tom Clancy's Sum of All Fears?--inks^T 04:57, 7 June 2006 (UTC)

Edit: It would me much simpler if they were to find a classified "suitcase nuke" that had been armed and left in that state until your characters discovered it (military hardware = overbuilt and very durable). Then detonation could be with a simple timer.--inks^T 05:03, 7 June 2006 (UTC)

Some (many? most?) nukes were detonated in the air shortly before hitting anything to cause damage over a wide area. That means they either use a timer or were remotely detonated by some sort of electronic signal. It would be easy to make plot twists on this, seeing as how it's in the future, and you could probably think of a lot of "traps" that could have been set up in the programming. E.g. calling on the remote "foob()" function detonates the bomb instantly, wheras "executeBomb()" causes it to malfunction or go on some kind of rampage sub-sequence. Then again, I always think it's best when you don't try to explain such things in stories, because the cooler you try to make it, the lamer it becomes. The mere fact that most people can't imagine how bombs actually work and detonate makes them believable.  freshofftheufoΓΛĿЌ  05:14, 7 June 2006 (UTC)

Yeah! Most people know nothing about nuclear physics and engineering. In your story, you gotta have one of your characters display a great knowledge about nuclear weapons design, then have him rig it up. Many to most nuclear weapons were detonated after being dropped out of a plane—the rest were set a top 20-40 m steel towers. — The Mac Davis] ⌇☢ ญƛ. 05:43, 7 June 2006 (UTC)

Warheads are designed to be very difficult to set off accidentally. While some nuclear warheads have been fitted with contact or proximity fuses, there is always an additional arming step before the fuses become 'live'. If you check out the List of military nuclear accidents, you'll find a number of instances where aircraft or missiles carrying nuclear warheads have crashed or been destroyed by fire. While in some cases radioactive contamination of the immediate area and detonation of the conventional high explosives have occurred, there has never been an accidental nuclear explosion.

The device or scheme that you're looking for is the Permissive Action Link (PAL). Interestingly, you probably are really looking for a codebook. If you read through some of the external links from that article, you can get a pretty good idea of what might make a plausible plot device. :D

I'll note in reply to Freshgavin's comment that airburst nukes don't employ a timer, and are never remotely detonated. (As suggested, there would be too much opportunity for mischief or failure.) Airbursts are triggered using a combination of air pressure sensors and radar altimeters. TenOfAllTrades(talk) 05:46, 7 June 2006 (UTC)

Good to know! I'll tell my hacker friends to forget about that bright idea then.  freshofftheufoΓΛĿЌ  06:38, 7 June 2006 (UTC)

A PAL device! Of course, why didn't I think of that! (And I call myself a Metal Gear Solid fan...) Thanks TenOfAllTrades. Can anyone confirm that American warships (even aircraft carriers) carry nuclear missiles? Or will one have to be removed from a fighter jet onboard the ship?

Well, on US Navy ships you might find nuclear-versions of the anti-submarine ASROC or TLAM/A nuclear land attack version of the BGM-109 Tomahawk. Whether they actually carry them regularly I don't know, but you might as well assume they do. No one's going to know any better! Sum0 10:16, 7 June 2006 (UTC)

Nuclear weapons have multiple safeguards against detonation. Not only the Permissive Action Link mentioned above, but a set of environmental sensors that check the expected physical conditions the weapon will undergo. For example, a ballistic missile will undergo acceleration (at liftoff), then free fall (the ballistic portion of flight) combined with low temperature and pressure, then increasing pressure as it returns to earth. If these conditions are not experienced (or experienced in the wrong order) the weapon won't denotate.

Airburst bombs typically don't use a timer, they use a ground-sensing radar proximity fuze or else an altimeter fuze. Gdr 14:07, 7 June 2006 (UTC)

While responsible countries likely do all of these things to prevent accidentally detonation, I doubt if countries like North Korea do. However, getting hold of one of their nukes in the story could be trickier. Perhaps it could be in the process of being shipped from North Korea to terrorists, hidden in a freight ship, when everyone died and the ship went adrift ? StuRat 17:31, 7 June 2006 (UTC)

The main reason for putting in place these safeguards is to protect your own personnel against accidents and sabotage. The more paranoid the regime, the more worried about the latter, surely. Certainly the Soviet nuclear weapons programme used a wide array of environmental sensors. Gdr 15:41, 13 June 2006 (UTC)

Everyone died? Seeing as it's in the future, how about North and South Korea go to war, and then North Korea sneaks a nuke into a bunker to attack South Korea, however they are pushed back and lose the bunker which is very well hidden (in some mountain range {I don't know), and then are afraid to reclaim it or claim ownership for fear of international reaction...and over time, the documents for it are lost (as it was a secret mission)...Well it's amazingly stupid but it's something

Anti Magnetic Metal/Substance

Which metal or substance doesnt allow magnetic effect to pass through that metal/substance.

Mu-metal. DMacks 06:36, 7 June 2006 (UTC)

Mu-metal has I think the highest known magnetic permeability of any material. — The Mac Davis] ⌇☢ ญƛ. 07:24, 7 June 2006 (UTC)

Sounds like a superconductor to me, since they expel external magnetic fields. To a limit, at least. Confusing Manifestation 09:16, 7 June 2006 (UTC)

Blue Eyes

Why are blue eyes rare? Also why are blue eyes so desirable?

See Eye_color#Blue_eyes — The Mac Davis] ⌇☢ ญƛ. 07:21, 7 June 2006 (UTC)

Here in the UK blue eyes are pretty common. -Benbread 20:40, 7 June 2006 (UTC)

Good question. If you can think back to high school biology (if you ever took it I'm assuming), you may have learned the basics of Mendelian Genetics which says that for every trait, there is a dominant allele and a recessive allele. In other words, the trait eye color has dominant and recessive colors. Blue eyes happen to be recesive; in that they, when paired up with say Brown eyes, are not expressed. For example: Let B = the allele for brown eyes, and b = the allele for blue eyes. Say your father has the heterozygous genotype Bb (brown eyes), and your mother has the homozygous genotype BB (brown eyes). When you were concieved, you recieved either a (B) or a (b) from your fathers sperm, and a (B) from your mothers egg. No matter what, though, the (B)-brown eye allele you recieved from your mother overrides the (b)-blue eye allele you -may- have recieved from your father. Hopefully I didn't confuse you more with the genetic-speak -- but if I did, read about Mendelian Genetics. If you're still with me then read on... Since it's a recessive trait -- it is generally not going to be as prevalent as a dominant eye color like brown would be. But as Benbread said, in certain areas, it may be common simply because many people that have blue eyes mate with other blue-eyed individuals; preserving the (bb) recessive genotype to the next generation. That's why Scandinavian countries and perhaps Germany and the UK have more blue-eyed individuals whereas places like the United States where there is a more diverse gene pool, do not. Hopefully that answered your question.

As for why they're desireable. Well that's more of a matter of opinion to be perfectly honest. Sure many will say that blonde-haired/blue-eyed individuals look better which is probably where you get the notion they're more desireable but again... a BH-BE person is no better than a brown-haired/brown-eyed individual. It's simply a matter of opinion. -Novaprospekt 02:29, 14 June 2006 (UTC)

Computer power-off

I checked an old hard disk for any important files it might contain, and to my dismay the computer booted Windows 95, contained by the disk. It was buggy as usual, but I noticed one neat feature I haven't seen on my regular OS (Debian GNU/Linux): it switched the computer's power off after system shutdown. Is there a way this could be enabled in Linux, too? –Mysid^(t) 06:56, 7 June 2006 (UTC)

• See, windows isn't all bad. ;) - Mgm|^(talk) 07:38, 7 June 2006 (UTC)

Every version of Linux I've run for many years has powered off the computer when I tell it to shutdown. There should be a /etc/init.d/halt script, which should call poweroff after doing what ever is appropriate with raid drives, UPS power supplies, etc. I suspect that Debian sets up fewer of these conveniences than the distros with fancy install programs, such as (K)Ubuntu (which is based on Debian).-gadfium 07:49, 7 June 2006 (UTC)

If you don't see a "poweroff" command, then you should take a look at what your copy of "shutdown" does. See shutdown. If I'm not running X11, I normally turn off the computer by typing (as root) "shutdown -h now", where the -h turns off the power.-gadfium 07:56, 7 June 2006 (UTC)

Shutdown, shutdown -h now, and poweroff do the same thing – shut down the system and print "Power down." on the screen. –Mysid^(t) 09:55, 7 June 2006 (UTC)

Linux's "least common denominator" behavior on shutdown is to simply put the processor into an idle state and halt execution. To actually turn off the power, it needs a driver to be able to talk to your motherboard's power management system. This is normally done using ACPI or, on older computers, APM. Try enabling both of those options in your kernel (I believe they're under the "device drivers" menu), and see if that helps. —David Wahler (talk) 04:16, 8 June 2006 (UTC)

Manufacturers make the hardware of commercially sold computers in a way that allows Windows to easily talk to it at a low level, allowing Windows to switch it off easily, but doesn't mean that manufacturers have made it easy for other platforms to do it. The point of ACPI was to have an industry standard for this kind of thing, and although Linux's support for it is technically incomplete, it still generally works in terms of turning the power off. The last thing I see on the screen of my Linux system before the machine turns off is "acpi_power_off called". ACPI support in Linux has gotten a lot better recently; try looking for the packages "acpi" and "acpid" on Debian. -- Daverocks (talk) 07:45, 10 June 2006 (UTC)

Way forward for Struts/Stxx application.

We have a large web application based on Apache Struts and STXX. This gives us a nice separation of business logic and presentation. We are now being asked to give an improved user experience with AJAX-like client side verification and dynamic form changes (e.g. displaying an optional question if you select "yes" in a Yes/no button group.

Is it possible to do this with an XSLT based framework. Can you maintain separation of presentation and business logic with AJAX? What open source solutions should we look for if migration is needed? -- Chris Q 08:30, 7 June 2006 (UTC)

Visual "chemical noise" in the brain

Close you eyes (this is important). Wait a while, in a dark room and you might see patterns. I've noticed these patterns, usually light areas that move around inside your brain, somewhere between your eyes and that projector screen called the imagination. First, what are these called? I assume they are chemical "noise". Ok, now I can 'will' these to move around, not with much accuracy mind you. Is there a name for what I am doing? I'd like to read up on it. Thanks. Mjm1964 09:36, 7 June 2006 (UTC)

I have noticed the ability to move them, too. I've experimented with it and came to the conclusion that it's because I move my eyes while they're closed. If you keep your eyes pointed at the same direction, the patterns won't move. –Mysid^(t) 10:00, 7 June 2006 (UTC)

"Phosphenes" --Femto 12:22, 7 June 2006 (UTC)

Just one moment of research and the whole reference desk knows it forever. Yay. Skittle 13:42, 7 June 2006 (UTC)

Floaters? Isopropyl 17:25, 7 June 2006 (UTC)

Ah!! I have the answer! I learned this a few weeks ago, because I have the same weird thing. I'll talk to you about it, because I've asked a few times and no body has told me anything worth... anything. They are not phosphenes, or floaters, both of which come from the eye itself, but they are known as closed-eye hallucinations. I see level 1 through level 4. You? You described it much better than I had. :) The patterns are like little dancing phantasmagoric sugar plum fairies. Usually for me they're green if I'm in a dark room, and red and yellow if it is bright light. — The Mac Davis] ⌇☢ ญƛ. 21:53, 7 June 2006 (UTC)

Ah hah! When I was young I used to see Level 3 quite frequently, but not so much now that I am an adult. Perhaps if I indulged with Ms. Jane they would come back. --Ginkgo100 ^{talk ʘ contribs} 03:13, 8 June 2006 (UTC)

Most interesting. I get level 1 when my eyes are open as well as closed (I thought of it as static and didn't see the link) and used to get level 3 a lot. Maybe I don't do enough involved maths anymore. When very relaxed (not quite sleeping) I can get level 4, and used to play with that when I was little. Odd, I never really thought about them before. Skittle 11:08, 8 June 2006 (UTC)

See also Retinal fatigue.--Jondel 01:59, 9 June 2006 (UTC)

Medical Question: Disinfectant

When surgeons want to amputate a person, they immerse the knife and other cutting tools in a liquid to prevent infecting the human with some disease and germs in order to avoid killing the patient.

What is that substance? Is it ethanol or hydrogen peroxide? Patchouli 11:32, 7 June 2006 (UTC)

• It could be ethanol, but it's quite possible - and in my opinion more likely - it's another specially created chemical entirely. - Mgm|^(talk) 11:47, 7 June 2006 (UTC)

Now a disinfectant is only used when instruments can not be sterilized by autoclaving. Historically, commmon disinfectants have included phenol (carbolic acid) and ethanol. During 18th and 19th century battlefields and naval warfare, liquor with a high alcohol content or even hot tar or red-hot iron cautery was used. alteripse 12:00, 7 June 2006 (UTC)

• Is it safe to use hydrogen peroxide in the absence of other things?Patchouli 13:01, 7 June 2006 (UTC)

• • Safe yes, effectiveness incomplete or partial. alteripse 14:22, 7 June 2006 (UTC)

• • 6% hydrogen peroxide is an effective high-level disinfectant [4], as long as the instrument to be sterilized is properly cleaned first (no gunk left behind to shelter pathogens) and sufficient exposure time is allowed (for objects with narrow crevices and channels, up to 20 minutes). There are reports that acidifying the solution somewhat increases efficacy, as does the addition of a small amount of surfactant. As noted above, autoclaving is definitely the preferred method, however. Single use items are often gamma irradiated by the manufacturer. TenOfAllTrades(talk) 15:03, 7 June 2006 (UTC)

• How do they keep the instruments sterile between their removal from the autoclave and use in surgery ? StuRat 17:18, 7 June 2006 (UTC)

• Instruments (or, for smaller tools, instrument trays) are wrapped before autoclaving. The covering isn't removed until just before use. TenOfAllTrades(talk) 18:29, 7 June 2006 (UTC)

Hydrogen peroxide does have the disadvantage of turning into water and oxygen over time, so alcohol may be safer, since it won't do that. I suspect that hydrogen peroxide is more likely to cause the instruments to rust, too, although not to the extent that bleach would. On the other hand, alcohol is both volatile and flammable. StuRat 17:18, 7 June 2006 (UTC)

A few notes: ethanol requires long contact times to be an effective disinfectant, and some viruses and bacterial spores are somewhat resistant even after long exposure. (The tuberculosis bacterium and the hepatitis B virus are a couple of examples that come to mind.) Bleach too loses effectiveness with time, as the chlorine is volatile. Bleach is also inactivated if there is a large amount of organic matter. TenOfAllTrades(talk) 18:29, 7 June 2006 (UTC)

I had never heard of an autoclave before. The article was informative. Are there specially trained people who work with autoclaves, or do the doctors just handle their own instruments, or have nurses do it, or what? Is there school for autoclave operators? moink 18:11, 7 June 2006 (UTC)

Hospitals and research institutes that are of any reasonable size will have individuals who carry out sterilization services full time. While autoclaves aren't usually particularly difficult to use, a certain amount of care must be taken because they do operate at high heat and pressure. Autoclave operators must also be familiar with good quality control practices—there are various tests that are performed regularly to verify that appropriate (pathogen-killing) temperatures are reached throughout the autoclave volume. TenOfAllTrades(talk) 18:29, 7 June 2006 (UTC)

I think of an autoclave as a medical pressure cooker. Is that a reasonable analogy?

Yes. By the way, the term "disinfection" refers to a level of microbial kill that is generally considered inadequate for surgical-level asepsis. The most commonly used room-temperature chemical "sterilant" is glutaraldehyde. This is the agent used on surgical intruments that cannot be heat-sterilized, such as flexible endoscopes, that have parts that would be damaged by heat.

Now, if anybody could elaborate on that blue stuff the barber uses on straight-edge razors...--Mark Bornfeld DDS 19:41, 7 June 2006 (UTC)

You mean barbicide? --Kainaw ^(talk) 19:44, 7 June 2006 (UTC)

And here I thought that was the name of the crime when you set your little sister's Barbie doll on fire. :-) StuRat 20:33, 7 June 2006 (UTC)

Windows Source Code

I don't know about computer programming. Nonetheless, I have become curious about the source code of the Windows XP Professional operating system that governs all the interactivity between Windows and applications software, utility programs, and so forth. I want to scroll through the entire code to see it.

Please enumerate the list of menus and options that will lead me to the code for Windows XP.Patchouli 13:07, 7 June 2006 (UTC)

Windows is mostly a closed source product, although see shared source as well. -- Rick Block (talk) 14:12, 7 June 2006 (UTC)

Yes, if you want to see the source code for an OS, you should try your hand at open source ones such as Linux. --Chris 14:16, 7 June 2006 (UTC)

However, the Windows source code was partially leaked in early 2004. You can read an article here about it. Perhaps the code is still floating around somewhere. --Chris 14:20, 7 June 2006 (UTC)

1. Do you think every board member of Microsoft has seen the complete source code for Windows?
2. Are the source codes of major search engines such as Google and Yahoo! closed source codes?Patchouli 14:29, 7 June 2006 (UTC)

1. I doubt any one person, even Bill Gates, has seen the complete source code for Windows, assuming we take "seen" to mean something beyond superficial overview. However, the project management types should all be familiar with whatever document structure is used to formally define that particular Windows version.
2. Closed. See PageRank for info about Google's. — Lomn Talk 14:47, 7 June 2006 (UTC)

It's also worth noting that the source code for operating systems is quite complex. It's not the same as a program source code that you would find running within the OS. --Chris 15:07, 7 June 2006 (UTC)

And a lot of what you probably consider intuitively to be "Windows source code" is likely only a component of the operating system (that is, a lot of it is no doubt bound up in drivers and DLLs). Frankly, if you aren't someone trained in computer programming, what do you plan to make of it? It will likely be as equally incomprehensive to you as the code for the Linux kernal. --Fastfission 12:31, 9 June 2006 (UTC)

Type of Wood (Picture of Veneer)

Hello, I was wondering what species of wood is displayed on the attached photo of a wood veneer on a door. Thank you very much for any help that you can provide! --PrincepsLupus

Hmmm... that pic narrows it down to about a dozen. We need to see the grain up close before making a determination (although if it truly is a veneer then that narrows it down a bit more). Could you post a closeup?--Anchoress 17:48, 7 June 2006 (UTC)

Here is a closer up look at the actual grain. --PrincepsLupus

The wide spacing of the grain suggests a softwood such as pine or cedar, rather than a hardwood such as oak or cherry. The color is irrelevant; many softwoods are stained to resemble cherry wood. --Mark Bornfeld DDS 19:33, 7 June 2006 (UTC)

Hmmm, weird, my edit to this page just disappeared lol. Anyways, I agree with you Mark, my first thoughts were pine, fir or cedar (in that order), but the issue is whether or not it's actually a veneer. Because why would anyone bother veneering with a cheap wood, unless the door is made of coreplast or styrofoam? If it is veneer, I'd guess rosewood or mahogany.--Anchoress 06:14, 8 June 2006 (UTC)

It also depends where the door is - a lot of countries have native timbers that might appear like that (if the door were in New Zealand, for instance, I'd hazard a guess at rimu. Mind you, that is itself a kind of pine). Grutness...wha? 09:23, 8 June 2006 (UTC)

Thank you all for your help - my father is building a bunch of desks for a company whose doors and wooden trim are that wood, and they want the desks to match that, yet are unable to tell what kind of wood it is, and he wasn't sure either. I really appreciate the answers. --PrincepsLupus

Atomic radii exception

In a book, I found that atomic radii of oxygen(73 Ă) is greater than that of nitrogen(70 Ă). But no reason for this exception was given. For chromium, the case is of half stable configuration. But I was not able to find any reason for it. Even all my classmates (I am a student) are not able to find anything. But I have confirmed that this is true.

I shall be very grateful to anyone who is able to give a reason of this exception.

--61.0.204.248 Dhruv Kumar India.

Every reference I've checked gives 75 angstroms for the covalent radius of nitrogen. Isopropyl 17:23, 7 June 2006 (UTC)

This looks like it could be an error in the book. — TheKMan^talk 19:38, 7 June 2006 (UTC)

Fear of witnessing eye injuries?

Is there a specific term for the fear of witnessing an eye injury (or an image of an eye injury)? Zagalejo 17:54, 7 June 2006

The exact fear doesn't seem to be on this list, but if you look thru it you might find something close.--Anchoress 18:11, 7 June 2006 (UTC)

I must have this fear, as eyeball surgery makes me ill, especially when they start sewing on the eyeball. If they pull out a staple gun, I'm gonna toss my cookies for sure. :-) StuRat 20:45, 7 June 2006 (UTC)

I don't think you have a fear, but more like me, I just have to turn around, and turn up my music really loud to block out any surgeon commentary. Gives me the creeps. I can watch any other surgery (well, birth is pretty disgusting), but the eye surgery takes the cake. How could they show that!??? On TLC?? — The Mac Davis] ⌇☢ ญƛ. 22:05, 7 June 2006 (UTC)

Perhaps a more interesting question is, why would that be? Why are people (including myself) so squeamish about eyes? I can handle images of, say, brain surgery, but just the thought of eye surgery makes me cringe. Zagalejo 01:13, 8 June 2006 (UTC)

Because the eye is one of the "raw" parts of the body? No skin... Just speculating, though. -- Миборовский ^{U|T|C|M|E|666} 01:36, 8 June 2006 (UTC)

Also just speculating, but I think it is a result of the fact that the eyes are both very sensitive and very important sensory organs to humans. Fear of eye injury would be adaptive, and that fear could easily be expressed in a fear of seeing eye injury. --Ginkgo100 ^{talk ʘ contribs} 03:18, 8 June 2006 (UTC)

Interesting... Thanks to everyone who's commented so far! Zagalejo 17:05, 8 June 2006 (UTC)

Try also : googlimages for "chien andalou". --DLL 21:47, 8 June 2006 (UTC)

N's in chemical nomiclature

I see 'N's' used in two different ways in chemical names, and I don't really understand their meaning.

• Example of type #1 - N,N'-hexamethylene bis(acetamide)
• Example of type #2 - n-heptyl β-D-glucopyranoside

Can you explain? ike9898 20:39, 7 June 2006 (UTC)

Capital 'N' is most likely referring to nitrogen. Italicized lowercase n probably refers to the conformation of a particular molecule. In naming alkyl chains like #2, n-heptyl refers to the straight-chain seven-carbon alkyl substituent. Isopropyl 20:43, 7 June 2006 (UTC)

Isopropyl is correct. Capital N refers to point of attachment on a nitrogen atom. Lowercase n is short for "normal" and indicates that a chain has no branching. See IUPAC nomenclature of organic chemistry for all kinds of fun details. --Ed (Edgar181) 20:53, 7 June 2006 (UTC)

Thanks Ed, I always forget what n stands for. I'll make a mental note :) Isopropyl 20:58, 7 June 2006 (UTC)

(edit conflict, wahoo) It's important to realise in science captilising of a letter ususally completely changings it meaning. Eg. for a simple chemistry example (i dont know if these chemicals are stable but thats irrelavant to the point)
ClRbH = one chlorine, one rubidium, and one hydrogen atom
CLrBh = one carbon, one lawrencium, and one bohrium aton
But this extends far beyond chemistry and atomic equations. Philc _T^E_C^I 20:57, 7 June 2006 (UTC)

Benign Prostatic Hyperplasia

What are the possible causes of Benign Prostatic Hyperplasia in young males age 20 to 25? Please include any possible risk factor(s) attributed to a paticular segment of the community be in race, lifestyle, or truma.

Thank you Regies Graham

Please dont double post, especially in such quick succesion. Philc _T^E_C^I 21:20, 7 June 2006 (UTC)

Please check the article we have on Benign_prostatic_hyperplasia. This is an encyclopedia you know. — The Mac Davis] ⌇☢ ญƛ. 22:14, 7 June 2006 (UTC)

The article we have does not really answer the question though. The vast majority of people affected by BPH are over 50. Getting BPH at 20-25 would be almost unheard of (and a PubMed search seems to vindicate this). I'd venture to suggest that although there are no international standards of diagnosis for BPH, a benign enlargement of the prostate in a male under 25 would probably not be diagnosed as BPH, simply due to the fact that BPH is a condition primarily associated with ageing and long term presence of testosterone. If you get prostate enlargment at 25, those key criteria are not met, and so it's probably caused by some pathology unrealated to the normal BPH mechanism.--inks^T 22:19, 7 June 2006 (UTC)

Product that creates a rubber coating on metal

I need the name of product I have heard of before. You dip something like a pair of metal plyers in this product and the object comes out covered with a thin coat of rubbery stuff. You might use it on metal parts to prevent rust, or to provide electrical insulation. Know what this stuff is called? ike9898 21:10, 7 June 2006 (UTC)

Plasti Dip? http://www.caswellplating.com/aids/plastidip.html--inks^T 21:42, 7 June 2006 (UTC)

There are many types and brands of this kind of product. Google for rubber handle dip for many hits. DMacks 21:52, 7 June 2006 (UTC)

You could just drop by your local hardware store and they should have it. It's often used to coat the handles of tools. Dismas|^(talk) 01:50, 8 June 2006 (UTC)

Warning: this product is not intended for use as a contraceptive. Any such usage may be injurious to health and will void the manufacturer's warranty.

Vegetable People

If you lost all of you brain apart from the parts associated with Homeostasis and controlling basic functions (if there any any recquired other than homestasis), could an animal or human survive as a complete vegetable. And out of interest, what are all of the organs that we can live without, eg. we dont need a stomach providing our food is sterilised, in a paste or liquid, and emulsified (or do we), and others. Philc _T^E_C^I 21:19, 7 June 2006 (UTC)

Do you want to elaborate on the question? Because the answer to "Could an X survive as a vegetable if it still had organs and brains to run basic functions?" is of course "Yes", because "Basic Functions" could certainly mean "Enough functions to enable a vegetative state of existence".--inks^T 21:39, 7 June 2006 (UTC)

The notorious Terry Schiavo case is a well-known example of a person in a vegetative state who had no trouble surviving, with the critical exception that she could not feed herself, so nutrition had to be provided via a feeding tube. When the tube was removed, she died. So I suppose that if you wanted to be pedantic (and oh, don't all we Wikipedians want to be pedantic?), you could say that in a vegetative state, one could not survive because one could not feed oneself. As for organs, I know people can survive with partial bowels and partial kidneys, and without any gall bladder or spleen. I'm not a physician, so that's about as much as I can say on that subject. --Ginkgo100 ^{talk ʘ contribs} 03:24, 8 June 2006 (UTC)

Theoretically, you could keep subtracting parts from a human (legs, arms, skin, etc.) providing there was a welcoming enough enviroment to protect it, and you would be left with (in a way) nothing but a vegetable. If you just keep on taking out non-essential systems of the body, eventually you'd be left with nothing more than a single cell... theoretically speaking!  freshofftheufoΓΛĿЌ  05:13, 8 June 2006 (UTC)

I specified homeostasis, the quetion was meant to mean (among other things), can you survive with no parts of the brain apart from homeostasis, and if not, what do you need. Philc _T^E_C^I 17:45, 8 June 2006 (UTC)

Sodium methoxide

I would like to know the process for manufacturing sodium methoxide and all the physical data for the reagents and the products. Data such as

density, viscosity, surface tension, heats of reaction, heats of fusion all thermodynamic properties, reaction rates of formation, ideal conditions for the reaction, etc.

You obviously haven't done much research yet. Sodium methoxide is a solid until 150 C, therefore you can ignore viscosity and surface tension. You should probably say how toxic it is in addition to all those. Why don't you do a google search for each permutation. "sodium methoxide density" "sodium methoxide viscocity." — The Mac Davis] ⌇☢ ญƛ. 22:23, 7 June 2006 (UTC)

Wood

Does wood have any nutritional value to humans? — The Mac Davis] ⌇☢ ญƛ. 22:36, 7 June 2006 (UTC)

No, humans lack the enzymes to digest cellulose (although it is useful as roughage).-gadfium 23:01, 7 June 2006 (UTC)

Wood is not entirely cellulose. I believe there are small amounts of simple sugars, and other organic molecules that a human could technically utilize. The major problems is that these are in low concentration, and that our digestive system is poorly adapted to with deal with something that is so hard, and highly insoluble. ike9898 13:53, 8 June 2006 (UTC)

But note that humans often eat the wood (specifically the bark) of Cinnamomum verum. --Ginkgo100 ^{talk · contribs} 03:29, 8 June 2006 (UTC)

But much more often, at least in the US, of Cinnamomum aromaticum, I recently discovered. —Keenan Pepper 04:00, 8 June 2006 (UTC)

Which I actually prefer. I keep cassia sticks in the cupboard and grate it fresh when needed... --Ginkgo100 ^{talk · contribs} 19:34, 8 June 2006 (UTC)

In Norway during periods of hunger in the middle ages, bread was made from a mixture of barley flour and bark from elm or pine trees. I suppose the bark was added mainly to make the flour last longer, but I wouldn't exclude the possiblity that it had some nutritional value (carbohydrates other than cellulose?). Anyway, here are some pictures of a lady baking "bark bread", the text is in Norwegian only. --21:29, 8 June 2006 (UTC)

Cellulose (ie, sawdust) is commonly added to powdered or ground dry foods, especially dry cheeses, to keep it from clumping together if it gets damp. --Serie 18:19, 9 June 2006 (UTC)

Some mammals digest cellulose : bovines and other ruminating ones. Others don't, which causes horse or elephant dung to be used for specially decorated papers. Now you know to what kind of animals we are related. --DLL 21:41, 8 June 2006 (UTC)

Penicllin

Allergic reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent. Anaphylaxis will occur in approximately 0.01% of patients. (Rossi, 2004) There is perhaps a 5-10% cross-sensitivity between penicillin-derivatives, cephalosporins and carbapenems; but this figure has been challenged by various investigators.

What do each of these things mean? I just wanted to know how many people were allergic to this thing. — The Mac Davis] ⌇☢ ญƛ. 22:36, 7 June 2006 (UTC)

About 10% will exhibit some sort of allergic reaction. About 0.01% will have a life-threatening reaction. --Serie 23:21, 7 June 2006 (UTC)

The usual effect that gets a person labeled as pcn allergic is simply a rash. Because there are other antibiotics, the label is rarely challenged and when it is, is often not provable.

Anaphylaxis is a severe and potentially deadly allergic reaction usually involved swelling of the windpipe (laryngeal edema) and/or a drop in blood pressure, leading to asphyxia or cardiac arrest. A risk of 0.01% means 1 in 10,000 patients.

There have been rare cases where a person with a severe pcn allergy also reacted severely to one of a different class of antibiotics. The event is too rare to yield reliable statistics but the 5-10% risk is often cited and hard to disprove. The risk of cross-reaction when the pcn allergy is nothing but a vague rash history is probably much lower. alteripse 23:35, 7 June 2006 (UTC)

Hams at the desk

Do we have any hams around here? I just got my technician class license two days ago. — The Mac Davis] ⌇☢ ญƛ. 22:36, 7 June 2006 (UTC)

Seacrch around in wikibooks, such as wikibooks:Amateur Radio Manual, or even try to look at wikia. – b_jonas 09:22, 8 June 2006 (UTC)

I mean, if there was a community on wikipedia, you'd probably find them at Portal:Browse, but I can't find them there. – b_jonas 09:35, 8 June 2006 (UTC)

CQ. QSL? G0GNF G N Frykman 20:43, 8 June 2006 (UTC)

Who are you going to talk to? --Username132 (talk) 23:00, 8 June 2006 (UTC)

Hi, I was a ham operated for many years, no longer active. Held callsigns G4JRT, and Vk4Ern.-User talk. erniehatt.Ernie

Injecting heroin into the eyeball?

Do desperate junkies who've used up all their veins actually do this? I've often heard this story repeated but it sounds like an urban myth to me. --Kurt Shaped Box 22:34, 7 June 2006 (UTC)

They could never use up all their veins could they? — The Mac Davis] ⌇☢ ญƛ. 22:38, 7 June 2006 (UTC)

After years of addiction, they can certainly collapse all the surface veins large enough to accept a needle. Sometimes they have to resort to injecting into the cock vein (ouch!). This is where the 'eyeball story' usually comes in... --Kurt Shaped Box 22:49, 7 June 2006 (UTC)

What do you mean the cock vein? There's only one? — The Mac Davis] ⌇☢ ญƛ. 22:51, 7 June 2006 (UTC)

Well, looking at my cock, there's certainly one long, thick vein. The smaller ones would probably rupture if I was to try injecting anything into them... --Kurt Shaped Box 22:53, 7 June 2006 (UTC)

I'm no doctor, but that "thick vein" you're thinking about may be your urethra. Injections there would probably not give the desired effect (as it would probably all leak out that hole at the end of your penis that you might have noticed). 65.96.221.107 00:57, 8 June 2006 (UTC)

(I can't believe I'm entering into this discussion). In any case, the "cock vein" being referred to is most likely NOT the urethra (which is far less visible and on the underside of the penis), but an actual vein carrying blood. Don't ask me why I know this, just trust me. (No, I've never injected anything into it!) ;)Loomis51 01:50, 8 June 2006 (UTC)

I can't believe I'm getting involved here, either. There are a number of veins in the penis; the most obvious is the superficial dorsal vein (pic). If you accidentally stick the needle in too deep, I suppose you would end up just below that, in the aptly-named deep dorsal vein. (I have no comment regarding my opinion of people who a) stick needles into their penis, and b) are incautious enough to stick it in too deeply when so doing.) There are a number of smaller veins that are often visible over the entire surface of the penis (save for the glans); they're almost always smaller than the dorsal veins, and probably (even) worse targets for injection. Let me just say, ouch. TenOfAllTrades(talk) 02:14, 8 June 2006 (UTC)

IANAD, but if you injected anything into your vitreous humor, it would take a while to work its way into your bloodstream. —Keenan Pepper 23:47, 7 June 2006 (UTC)

For what it's worth, the metabolic exchange and equilibration between systemic circulation and vitreous humor is so slow that vitreous humor is sometimes the fluid of choice for postmortem analysis of glucose levels or substances which would be more rapidly diffused, degraded, excreted, or metabolized from the general circulation. I vote for false urban legend as well. alteripse 11:28, 8 June 2006 (UTC)

I took the liberty of putting that fact in the article. —Keenan Pepper 21:52, 8 June 2006 (UTC)

Looks like it would hurt.--Proficient 03:05, 10 June 2006 (UTC)

In case anyone wants to try to do actual research on this, I think the story is that the heroin is injected into the tear duct, not the actual eyeball. --Monguin61 19:27, 14 June 2006 (UTC)

Breathing from the freezer

Why is it that when I stick my head in the freezer and take a big gulp of air I end up coughing it out and having to breath room temp air? — The Mac Davis] ⌇☢ ญƛ. 22:51, 7 June 2006 (UTC)

At a guess, I'd say that your lungs don't particularly like the ice crystals in the frozen air. As a matter of interest, why have you been sticking your head in the freezer and taking deep breaths? :) --Kurt Shaped Box 22:55, 7 June 2006 (UTC)

Sticking your head in the freezer is a great way to cool down after exercising hard. As a side benefit, there's a refrigerator full of cold drinks within easy reach. --Serie 23:25, 7 June 2006 (UTC)

What? No body else attempts low-cost cryogenics? — The Mac Davis] ⌇☢ ญƛ. 23:43, 7 June 2006 (UTC)

You're probably destroying your alveoli if you do that, at -20 degC. -- Миборовский ^{U|T|C|M|E|666} 01:32, 8 June 2006 (UTC)

Sadly, i know exactly what you're talking about. And, i suspect it's the humidity in your lungs dropping below freezing and condensing on your alveoli (cells that let oxygen and co2 in and out of your blood). At least, thats what the strange freezing and burning sensation feels like to *me*. I second the suggestion that you not do that if it bothers you. Instead, try drinking cold water or pressing large pieces of ice against your face.

This happens to me also. I don't stick my head in the freezer, but I do occasionally have to inhale during the winter when it's -10º F (-25º C), and whenever I take a deep breath, it always hurts my lungs and makes me cough. Shallow breaths are usually OK. -lethe ^{talk +} 04:53, 8 June 2006 (UTC)

It might be a reaction similar to bronchospasm. Cold air sometimes triggers an asthma attack in asthma sufferers. - Cybergoth 05:30, 8 June 2006 (UTC)

Are you inhaling through your mouth? It might not be so bad if you inhale through your nose, so the nasal structures can warm the air a bit before it hits your lungs. --Ginkgo100 ^{talk · contribs} 19:39, 8 June 2006 (UTC)

You think the freezer is bad? You should try taking a deep breath of dry ice in through your nose. That stings. Rockpocket 04:58, 9 June 2006 (UTC)

Careful with the comparison...breathing vapor off of dry ice also brings you acidity in addition to "very cold". DMacks 06:43, 9 June 2006 (UTC)

Absolutely. Resulting in your CO₂ sensing olfactory neurons going haywire, which is not a GOOD THING. Don't anyone try it at home, btw, as it really isn't very clever. I'm a professional ;) Rockpocket 07:03, 9 June 2006 (UTC)

Clearly most of you haven't done it. Do you know how good the cold air in a freezer smells? (I am serious)Johndoe 111 08:48, 11 June 2006 (UTC)

Boranes and regular polyhedra

I'm a long-time question answerer at these reference desks, but I think this is the first time I've asked a question.

Boranes with a formula of B_nH_n^2- are in the shape of a regular polyhedra with triangular faces, where the number of points on the polyhedron is the same as the number of boron atoms. This is the closo configuration, and from that I can work out the nido and arachno configurations for different ratios of B to H.

• For 4 borons, the shape is a tetrahedron.
• For 5 borons, the shape is a trigonal bipyramid.
• For 6 borons, the shape is an octahedron.
• For 7 borons, the shape is a pentagonal bipyramid.
• For 8 borons, the shape is a dodecahedron.
• For 9 borons, the shape is a tricapped trigonal prism.
• For 10 borons, the shape is a bicapped square antiprism.
• For 11 borons, I don't know what the shape is called.
• For 12 borons, the shape is an icosahedron.

We were told in class to memorise the names, and to be able to draw the simpler ones. Somehow, I've ended up with a picture of the 11-pointed polyhedron in my notes but no name for it. I've looked through our articles on polyhedron but not recognised it, and I'm not a mathematician so I know know how to describe it in mathemetical terms such as by Wythoff formula.

To sum up: can anyone tell me what a 11-pointed polyhedra with triangular faces is called?-gadfium 22:58, 7 June 2006 (UTC)

Never mind, I've found it. It's an octadecahedron.-gadfium 23:19, 7 June 2006 (UTC)

Fake tans?

What ingredient is it that makes fake tan smell so bad? My friend and I tried to compare ingredients of 3 but werent sure (its sad but its summer and we got bored)

thanks a lot

Most sunless tanning products contain a chemical called Dihydroxyacetone (DHA), which gives them a strong odor. — TheKMan^talk 23:36, 7 June 2006 (UTC)

Your breath smells even worse if you swallow it. — The Mac Davis] ⌇☢ ญƛ. 23:42, 7 June 2006 (UTC)