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June 17

Cancer Rates

I was wondering why it is that the rate of cancer in our society today seems much higher than it was in years and centuries past. So this is a two part question: is this really true and why is this the case? I realize that this is a complicated question with no simple answer, but I was wondering if someone could explain it just a little. Thanks! Andromeda321 00:05, 17 June 2006 (UTC)

1. Because people live long enough to get it rather than dying of other causes.
2. Because we can now diagnose it readily. --Robert Merkel 00:17, 17 June 2006 (UTC)

Agreed. Since 100% of people still die, and far fewer die of some things, like bubonic plague, that means far more people must die of other things, like cancer, to keep the death rate at 100%. (If we ever fall short of the 100% death rate, then people will start living forever, and we can't have that, now can we ?) StuRat 01:35, 17 June 2006 (UTC)

Others claim that cancer rates have increased due to an increase in carcinogens in our evermore polluted environment and modern lifestyle. Melanoma, for example, is thought to be on the increase, possibly because high risk individuals become exposed to more UV at a younger age. This may be due to a combination of factors: an increase in intercontinental travel (childhood holidays to hot climates), because northern Europeans have colonised hot countries over the last few centuries, the fact that suntans have only become fashionable over the last 50 years and that UV exposure levels may be increasing due to ozone depletion. Then there are the hundreds of thousands (or perhaps millions) of past and future cancers that may or may not have been caused in part by radiation exposure after Nagasaki, Hiroshima and Chernobyl. Rockpocket 07:56, 17 June 2006 (UTC)

Chernobyl is probably still significant statistically in Eastern Europe (where entire countries were exposed), Hiroshima and Nagasaki, probably not. There are more people killed by lung cancer alone in the United States per year that died as a result of the bombing. (As for its contribution to worldwide fallout levels, anything it would have added was no doubt overshadowed by the decades of atmospheric nuclear testing which followed). --Fastfission 15:46, 17 June 2006 (UTC)

Many types of cancers are also lifestyle diseases, and you'd probably want to know trends of known carcinogens consumption as well (i.e. cigarette smoking, which can take decades to develop into cancer). I'm also guessing that there are other man-made issues such as coal pollution that come into play. Cancer is a complicated disease and its causal mechanisms are still being studied; additionally there are statistical questions (as noted above) which come into play, and it doesn't help that almost every cause has some sort of political aspect to it (making them endlessly disputed). --Fastfission 15:46, 17 June 2006 (UTC)

Is it possible to pull your own head off?

This may be the stupidest question of the day, but is it humanly possible to rip off one's own head? If I were sufficiently strong and motivated, by insanity, PCP, or boredom, would it be possible to decapitate oneself by pulling? I know for a fact that people's limbs have been pulled off by machinery. Follow-up question: would it be possible to sever one's own head with a hand-held knife, e.g. a machete? Don't ask me why these things are on my mind. Bhumiya (said/done) 00:20, 17 June 2006 (UTC)

I think both of those things are physiologically impossible, because even if you have strong mental motivation, the pain is so intense that your reflexes take over and prevent you from continuing. That's why people have to literally "fall" on their swords to commit suicide, because their reflexes prevent them from simply stabbing themselves. —Keenan Pepper 00:28, 17 June 2006 (UTC)

You don't have to fall on your sword. People are perfectly capable of stabbing themselves to death (hara-kiri, for example, or even just wrist-slitting with subsequent bleeding). Cutting off a limb is also possible. Ripping off might be another matter, and the head would be yet more difficult as you would be unable to move your arms after the spinal cord was severed, rendering that feat, I think, pretty much impossible. - Nunh-huh 02:29, 17 June 2006 (UTC)

I wonder what the force required to pull a head from a body is? --jpgordon∇∆∇∆ 02:36, 17 June 2006 (UTC)

It's big. The "Myth Busters" did a segment in which they explored the possibilty of decapitation by ceiling fan, and discovered it took a lot of force to sever a head - more than they were able to develop. Obviously it would be a great deal more to pull it off by blunt force. - Nunh-huh 02:39, 17 June 2006 (UTC)

Did they test that on a real person? Mr. Lefty _{Talk to me!} 02:43, 17 June 2006 (UTC)

No, that would have been difficult to budget for. They used a few person-standins. Ah, here's the synopsis. - Nunh-huh 03:04, 17 June 2006 (UTC)

I imagine, and this is just speculation, that if PCP were to remove all pain and/or care about pain, then one might be able to pull one's head so hard as to sever the spinal cord, at which point it would be impossible to continue to pull one's head the rest of the way off. --Ginkgo100 ^{talk · contribs} 04:00, 17 June 2006 (UTC)

I think that sounds reasonable, but then again, PCP addicts have done some pretty astonishing things to themselves. I remember reading about someone who peeled his face off with a broken mirror. Of course, this is different. I think if I were an abnormally strong individual with no sense of pain and a desperate, irresistible urge to decapitate myself, it might almost be possible, if I began by tearing up my neck and then snapped the spine with a single forceful jerk before I had the chance to bleed to death. The harder I think about it, the less plausible it sounds. Still, it might make for an interesting episode of CSI. Bhumiya (said/done) 05:39, 17 June 2006 (UTC)

Both this chap and this chap seem to have enough will power to cut off parts of themselves. Cutting of your own head would be a bit harder, due to the fact that you would lose conciousness pretty quickly if you didn't manage it on the first attempt and that its hard to think of a good reason for doing it to focus your mind. But that aside, i bet it would be possible with a long enough and sharp enough blade and enough power in your arms to generate the force required. I bet some of those samurai dudes could do it. Rockpocket 07:42, 17 June 2006 (UTC)

I think it would be extremely unlikely for it to happen, unless perhaps you had some kind of defect that made you have weak neck bones that would allow for the possibilty to pull off your head. A possible scenario would be this: Your head was "loose" to begin with (meaning you had some kind of bone disease or other ailment) plus you had strong arms, which would be unlikely considering how close the neck/head is to the shoulders. I wonder if anyone has actually pulled off their head out of the billions of masses. --Proficient 16:06, 17 June 2006 (UTC)

Maybe not, but a lot of people over the years have been told to pull their head in. A terribly rude injunction, I've always thought. There are so many more pleasant ways of telling a person their existence is no longer required. (lol) JackofOz 00:54, 18 June 2006 (UTC)

I don't think it's easy even to pull someone else's head off without some applience (though it'd be dangerous to try because you can get one's spine hurt seriously). As for cutting one's own head off, I think it's possible with a guillotine or some similar device. It might also be possible by lying on the rail and waiting for the train, but I don't know if that can be done so that it would reliably cut your head off on the first attempt. I don't know if it's possible with a sword, but I think only someone proficent in using the sword have a chance doing that. In any of these cases, it's ver likely to wound yourself heavily, even fatally, even if you don't succeed. So don't try this at home. – b_jonas 12:00, 23 June 2006 (UTC)

Help

Hello, I’m hoping you could provide me with some help. I have a physics final on Monday, and we got a review package that resembles nothing of the kind of stuff we’ve done in class. I hope these aren’t too many, here goes:

When a certain rubber band is distance x, it exerts a restoring force F = ax²-bx, where a and b are constants. The energy stored in the rubber band when stretched from x = 0 to x = L is:

a) 2aL –b

b) 2aL+2b

c) aL^3/3 + 2bL

d) -aL^3/3 + bL²/2

e) aL^/3 + bL/2

The correct answer is d. I have no idea how to get that, and the only reason I think it might be d is because it has a negative in front of the a because the Force is opposite the x

The next question: A 1kg mass moves in a straight line under the influence of a force. The potential energy is given by U(x) = 6x²-2x^3 where U is in joules and x is in meters. If the mass has a speed of 2m/sec when it is at x = 1 meter, its speed when it is at x = 0 is:

a) 0

b) 2 √2 m/sec

c) 3√2 m/sec

d) 2√3 m/sec

e) 2√6 m/sec

The answer is d. I am confused with this problem because it says “ mass moves in a straight line”, and then it mentions potential energy, which must be 0 because the object has no height. Extremely confused with this one, I think the formula might just be a trick and not actually be useful, but I have no idea. Afterwards in the next question, it asks for the acceleration (which turns out to be -6). If I knew how to do the above question I might be able to do the one after it, but I’m unsure and just completely lost. Any response would be very appreciated. – Hopelessly Screwed

I don't think we're supposed to answer homework problems, but too bad.

For question 1: When you stretch the rubber band, you're doing work on it against the restoring force of the rubber band. The key is that work (which is a form of energy) is given by $\int Fdl$. That is, the work done is the integral of the force exerted along a path (a negative sign is needed if "F" is the restoring force instead of the force exerted). In this case, the expression for the work is $W=\int _{0}^{L}(-ax^{2}+bx)dx$ (note that the signs are reversed because the work you do to stretch the band is the opposite of the restoring force). Hopefully you can integrate that to obtain $W=-{\frac {aL^{3}}{3}}+{\frac {bL^{2}}{2}}$

As for question 2, what they mean by "the mass travels in a straight line" is that it is restricted to the x dimension; i.e. there are no other dimensions in which to move. The problem is asking you to consider an arbitrary potential energy, not necessarily the potential energy due to gravity, so "height" is not an issue. For instance, this could be the potential energy of a spring that a mass is pushing against.

The key to this problem is conservation of energy. No matter where the mass goes, it's mechanical energy (potential energy + kinetic energy) will not change, (assuming no non-conservative forces like friction). Therefore, if you can figure out its total mechanical energy at some time, it will be the same at all other times. In this case, the potential energy depends only on position; you are given the expression $U(x)=6x^{2}-2x^{3}$, and kinetic energy is given (as always) by $K(v)={\frac {mv^{2}}{2}}$.

At some time, the problem says the mass has velocity 2 m/s, so it's kinetic energy is (1 kg * (2 m/s)^2)/2 which comes out to 2 Joules. At that time, it is at x = 1 m, so its potential energy is 6 * (1^2) - 2 * (1^3), which comes out to 4 Joules. Therefore, at all times (unless some outside force acts on it), its mechanical energy will be 6 Joules. When x = 0, the potential energy of the mass is 0 (zero), so the kinetic energy must be 6 - 0 = 6 Joules. Now, you can use the kinetic energy formula in reverse to figure out the velocity. $v={\sqrt {\frac {2K(v)}{m}}}$ This gives sqrt(2 * 6 Joules / 1 kg) = sqrt(12) = $2{\sqrt {3}}$.

By the way, a hint for finding the acceleration at x = 0: Since $W=-\int Fdx$, $F=-{\frac {dW}{dx}}$ and always remember that $F=ma$ where "a" is acceleration.

Hope that helps - good luck.--Bmk 05:19, 17 June 2006 (UTC)

In the first question, force $F(x)$ is dependent on $x$. Differential work done when stretching the rubber band by a length of $dx$ is $F(x)dx$. Work done in stretching rubber band from $x=0$ to $x=L$ is $\int _{0}^{L}F(x)dx$.

In the second question, it is not stated whether the force is position-indepdent (i.e. indepdent of $x$). To get an answer, some assumption is needed. Perhaps the unstated assumption is that the force is constant. With that assumption, you can calculate the work done, and therefore the increase in total energy in moving the mass from $x=0$ to $x=1$. The total energy of the mass at position $x$ is the sum of its kinetic energy (related to its speed) and its potential energy (given by the formula for $U(x)$) at that position. Given the boundary conditions, you can work out its initial kinetic energy (and therefore speed) at $x=0$.--72.78.101.61 05:11, 17 June 2006 (UTC)

It just occurred to me that in my interpretation of the second question (i.e. the "force" is external and not accounted for by $U(x)$), the question does not provide enough information to allow an answer to be calculated. Maybe Bmk's interpretation is the intended one.--72.78.101.61 05:43, 17 June 2006 (UTC)

"We haven't done calculus yet so I'm unfamiliar with integrals. Is there any other way? Thanks for helping!"

Sorry - calculus is the only way to go for a non-linear force like these. --Bmk 05:26, 17 June 2006 (UTC)

Orange peelings and antibacterial benefits

Not sure where I heard this, but I heard that orange peelings can be used to cultivate antibacterial agents such as penicillin. Am I completely wrong about this, or is there some truth to it?--24.231.16.109 04:40, 17 June 2006 (UTC)

Penicillium mold grows easily on orange peel. Just leave some oranges in a drawer or even your refrigerator too long and you will proabably be rewarded. Extracting the penicillin will be your challenge and you may want to make arrangements with your local pharmaceutical company to use their purificaction and testing facilities over a weekend, if you don't have a sterile separation and analytical lab in your basement. Next you will want to borrow some culture petri dishes and bacterial cultures in the microbiology lab of your local hospital to prove the stuff works. Good luck. alteripse 11:15, 17 June 2006 (UTC) PS: Keep in mind of course that penicillin costs maybe 10 cents a tablet.

Optics glossy/matte colours

OK, I want to explore different colours and how you can make them different. One aspect is the colour itself. Anoter aspect is the gloss, whether the colour is shiny or matte. What other optical aspects can affect the way a colour or surface visually appears? I guess there's also infrared. Can some animals see infrared surfaces? If a surface was truly infrared, what colour would a human see it as?--Sonjaaa 06:24, 17 June 2006 (UTC)

Translucency springs to mind. And yes, some creatures (such as certain species of insect) are capable of seeing infra-red. Provided all non-infrared light was absorbed, a human would see such a surface as black GeeJo ^(t)⁄_(c) • 07:30, 17 June 2006 (UTC)

You may also want to consult gloss (material appearance). --Michel M Verstraete 23:12, 19 June 2006 (UTC)

Alcohols and Sodium Metal

Why is it that primary alcohols react more vigourously with sodium metal than secondary and tertiary alcohols? 138.130.252.56 09:57, 17 June 2006 (UTC)

The alkyl groups are electron-donating and thus strengthen the O-H bond in the alcohol. This makes the alcohol a weaker acid and less likely to lose a proton to be reduced by the sodium metal. The more alkyl groups present, the more electrons get pushed into the O-H bond. G N Frykman 17:30, 17 June 2006 (UTC)

software testing

Hi, i would like to know about the most used software testng tools and why the thes tools are used ?? I would also like to know about the comparitive advantage with other tools Regards Tommy

Tommy, I think you need to make your question a lot more specific to get a useful answer. What kind of software are you referring to? What OS? From what point of view (data integrity, user friendliness, vulnerability to malicious attacks, etc). --vibo56 ^talk 19:23, 17 June 2006 (UTC)

Some of the external links in our Software_testing article may help. -- Avenue 00:46, 20 June 2006 (UTC)

The best answers may be broad categories:

• Compilers
• Scripting languages
• Debuggers
• Code profiling
• Bug reporting such as BugZilla

Many of these are packaged into an Integrated Development Environment (IDE). More specifics would be needed to give better answers. Nimur 17:13, 22 June 2006 (UTC)

this question is helpful for me...coz i m facing a problem that when i start my computer its bios start working but suddenly stuck!!!!...i wait for many minutes but vain....i restart it then bios run but.. when windows start it simultaneously says "saving your settings",... n again shut down..plz help me out.

Bios Virus

hi my old laptop has not worked for a month for so now its a bit expencive to get fiexd, so i lent it to a friend who sead they would look at it. they say it has a bios virus, i was wondering what a bios virus is?

That would be a Computer virus which has somehow affected your computer's Basic Input Output System. The BIOS is a small program that tells your computer how to startup. Although BIOS viruses are said to be rare, once your BIOS has been corrupted, there is not much that can be done. The term itself is a little misleading, as the virus does not "live" in the BIOS and can not replicate itself from there. But if your computer has been affected, the terminology is the least of your worries. --LarryMac 20:33, 13 June 2006 (UTC)

Resetting the CMOS just might work. Not sure, though. -- Миборовский 05:53, 14 June 2006 (UTC)

How do you reset the CMOS? --Silex 21:02, 14 June 2006 (UTC)

Laptops are tough. CMOS is located on your motherboard so you either have to open it up to expose the motherboard (NOT recommended) or ask your Dell/IBM/HP guy. -- Миборовский 22:27, 14 June 2006 (UTC)

Well where does the BIOS virus reside if it does not 'live' in the BIOS? And would 'flashing the CMOS' work? To do that, do I have to jump some pins or something? --217.44.0.212 10:56, 17 June 2006 (UTC)

Maybe a BIOS update will correct your problem by overriding the defect. What is the exact problem with your comptuer when you say that it's not working? Is the operating system not functioning, the computer not turning on at all, or something else?--Proficient 11:17, 17 June 2006 (UTC)

To clarify, a BIOS virus should be removable by flashing (not possible if you're already at newest version, though) or by resetting CMOS by removing the battery (CMOS battery, not laptop battery) for a few minutes. It can also generally be done by changing a jumper connection. But either of those ways requires touching the motherboard - not easy on a laptop. -Goldom (t) (Review) 11:44, 17 June 2006 (UTC)

Reccommended procedure:

1. Verify the claim that there is a problem with the bios. To do this, you might check if the laptop boots normally with a bootable CD such as knoppix. If this is successful, the problem is probably not with the bios.
2. If you want to restore bios factory defaults, you can normally do this from within the menus of the bios setup program. If you pay close attention while the pc starts its boot sequence, you will see a message which tells you how to open the setup program (it might be, for example, holding down the F2 key when the pc starts). A text mode setup program will open, with a menu. Somewhere, usually on the "Exit" menu, there is an option "Load Setup Defaults". If you are certain that the bios is messed up, this should restore it. You also need to "Save changes" before exiting. --vibo56 ^talk 13:35, 17 June 2006 (UTC)

Schrodingers Equation

Ok i know the what the equation looks like but how do you solve it for a given particle of some mass whose energy contribution is V(x,y,z)using the equation. could you show it using an example. how do you solve the hamiltonian? --Debanjum 11:59, 17 June 2006 (UTC)durin

could you be more specific - when you say the energy contribution is v(x,y,z) do you mean that its energy is a function of its position in 3 dimensional space? What do you want to do? find the wavefunction that satifies certain conditions or what?HappyVR 15:16, 17 June 2006 (UTC)

See Category:Quantum models for some examples. Conscious 05:11, 18 June 2006 (UTC)

How hard would it be to write this software?

Here's something which has been on my wish-list for awhile. I'm wondering how difficult it would be to pull off.

Basically, the program would be a web browser which could simulate a locally hosted Apache server. Why do it? Because then you could write applications in server-side languages like PHP and distribute them to people easily. No need to install a whole Apache server on their machine if it is just going to be run locally. If you could combine PHP, Apache, etc. into a browser-like application itself, then you could easily distribute PHP files to people and not have to worry about all of the idiosyncracies of actually installing a server.

Does that make sense, conceptually? I want a way to easily distribute PHP programs which are made to be run off of the local machine (and not as true web applications), but the only way to currently do that is to install Apache and PHP (not simple operations, and overkill). It seems like it shouldn't be impossible to have a browser-like-application which could itself replicate the behavior of a local server.

Possible? Impossible? Hard? Easy? Already done? Any thoughts would be appreciated. --Fastfission 16:00, 17 June 2006 (UTC)

I'm not aware of any such beast. If you want to avoid installing PHP, you would either have to integrate the PHP interpreter source code into your browser code, or write your own PHP interpreter. The former is not tempting to me from a maintenance point of view, and the latter is reinventing the wheel. I'd say both sound like a lot of work. But I agree, it would be nice if the user could just download the PHP+ServerEmulator plugin, and be ready to use your PHP program. --vibo56 ^talk 19:40, 17 June 2006 (UTC)

What I was hoping one could do is just integrate Apache into the browser and then integrate PHP into that. I don't know how much re-inventing you'd have to do — all of the code for PHP, Apache, Firefox, etc. is open source.. it's just a matter of fitting it all together neatly, I suppose. Which is probably hard. :-) --Fastfission 05:20, 18 June 2006 (UTC)

One approach might be to write a user-friendly installer that installs a browser, web server and PHP interpreter at the same time. Getting it right is not easy, however. A similar thing has been done for the windows version of LyX, but I have not been able to get the installation to work properly on my system (now trying again, uninstalling everything, reinstalling each package separately). --vibo56 ^talk 08:45, 18 June 2006 (UTC)

A best compromise is to use Client side scripts such as Javascript. This will entail sending them a script or HTML document. If you're familiar with PHP, Javascript should be very similar. Nimur 17:17, 22 June 2006 (UTC)

Biological classification systems

I was wondering - regarding the classification system of plants and animals: Is there an official board or similar organisation that decides when a new classification is valid. Some of the reclassifications I've seen seem to be based on published papers - which makes sense since these things are peer reviewed - but surely getting a paper published is not all that it takes - maybe some sort of consensus rules here, I've honestly no idea how it works in practice - I assume differences of opinion do arise - how are these sorted out? Are disagreements amongst biologists worked out in a similar to conflicts on wikipedia?HappyVR 16:09, 17 June 2006 (UTC)

I look forward to an answer to this question, but I sure hope that no one in the real world resolves conflicts like we do! Melchoir 18:51, 17 June 2006 (UTC)

The International Commission on Zoological Nomenclature and International Association for Plant Taxonomy approve names proposed by the discovering scientists. Rockpocket 19:34, 17 June 2006 (UTC)

Thanks, but I'm not sure if this was the answer I was looking for - the links you provide guides to the nomenclature of species, but I was thinking in terms of when a conflict occurs regarding the placement of a given species within one or another genus - ie issues of taxonomy not naming - can anyone help?HappyVR 19:47, 17 June 2006 (UTC)

I'm sorry, i misunderstood your question. This article seems to suggest the peer reviewed publication process is how one establishes new taxonomy. One assumes, like the scientific process in most disciplines, time determines whether the community will accept the proposal, based upon further work supporting or refuting the evidence. Like everything in science, there is often no "right" answer, it comes down to who has the most convincing argument.the answer to this posting would seem to support this. Rockpocket 00:14, 18 June 2006 (UTC)

Thanks, that pretty much answers it. I was wondering if there was an organisation that 'rubber stamps' these things such as the Linnean society or 'international body of biological scientists' - I don't suppose 'rubber stamps' are in keeping with the scientific ethic though.HappyVR 00:58, 18 June 2006 (UTC)

Taxonomy is a science and it is normal to have dissensions with new theories. The dispute between traditional taxonomy and cladistics is beginning old and is still sometimes in the focus of science media. What are the criteria to sort life forms : form itself, bones, tiny characteristics, genes ? This also a question of fashions, which must evolve. --DLL 20:29, 17 June 2006 (UTC)

See International Code of Botanical Nomenclature for the WikiPedia article relating to plant taxononmy. For botany, the fights seem to be fought at the congresses where the code is decided (next one due this year?). An interesting story giving some insight into the process is: The name Acacia retained for Australian species. As far as zoological toxonomy is concerned, the situation seems to be less formal, confirming what Rockpocket said. Butler says the following in his article on the issue of Pituophis Taxonomy (I quote the whole paragraph to make the context clear, the editor's note is the pertinent bit): "Before we discuss Pituophis, I first must describe the formal and informal processes of taxonomy. Formally, there are two groups that make decisions on the names of species; the American Association of Zoological Nomenclature, which is a satellite-organization for the International Commission on Zoological Nomenclature (ICZN). Generally, if there is a published dispute regarding the name of a species, the authors will present their case to the ICZN, and they will make a ruling based on their established code. However, more typically and informally, once a name sticks, and is used frequently, then the ICZN rarely gets involved. (Ed. Note: The ICZN judges on procedures and does not get involved with species validity - that is the purview of peer reviewed journals.)" So "peer reviewed journals" seems to be the case for zoology. --Seejyb 11:04, 18 June 2006 (UTC)

The various naming committees (ICZN, ICBN etc) adjudicate a very narrowly defined set of issues to do with biological names and biological types. So questions like, "what is the type specimen for the species Homo sapiens?" or "is the name Archaeoraptor available (in the technical sense of 'available')?" are appropriate for the committees. But questions about actual relationships, like "how many genera of gibbons are there?" are outside the scope of the committees and must be settled by research, peer review, and debate. Gdr 11:19, 19 June 2006 (UTC)

Sinking lifejackets?

I have heard an urban legend that the "old" lifejackets made of cork or kapok used to lose buoyancy after being immersed in water for a long (many hours) period of time? Can anyone confirm or deny this? Thank you for time. Mieciu K 14:08, 15 June 2006 (UTC)

A styrofoam one would be better... Would you like a lifejacket like this; it's incredibly light.

Kilo-Lima|^(talk) 17:18, 17 June 2006 (UTC)

But I'm interested in lifejackets that sink. I have heared sinking lfejackets caused deaths during the USS Indianapolis (CA-35) dissater, and others but I'm unable to confirm it. Mieciu K 21:17, 17 June 2006 (UTC)

According to this NOVA transcript, early cork lifejackets had many problems: "The buoyancy is equally distributed around the body, around the front of the body and around the back of the body. So, if the person was unconscious and was lying face down on the water, he would remain stable in that position. Secondly, there was no support for the head or neck. It's really just wrapped around the top of the body, leaving the shoulders and head out of the water. And that's fine for somebody who is conscious, who is alert, who is able to hold his head out. But the head actually is very heavy, the specific gravity of the head. When a person loses consciousness, the neck muscles are failing, and then the head tends to flop forward, and they could be found floating face down in the water, inhaling the water." However, I can find no reports of cork or kapok lifejackets actually breaking down and losing their buoyancy. I would expect that cork would be fairly resilient. Consider how long corks survive in bottles of wine without breaking down. Then again, cold water might have a different effect. Also, any lifejacket, even one made from synthetic fibers, can break down if it develops a tear or becomes infested with mold, mildew, etc. I think the Indianapolis survivors may have had problems remaining upright. Their unbalanced lifejackets would have required them to constantly maintain their balance in the water. If you lost consciousness or became too tired, it would be easy to turn over in the water and drown. But I can find no evidence that life jackets actually sunk. Bhumiya (said/done) 01:36, 18 June 2006 (UTC)

IIS

I might be migrating from Apache to IIS sometime soon (and hence PHP -> ASP.NET). Here are a few questions...

• Is there an ASP.NET interfact for PhpBB? I have a lot of mods and I don't want to have to migrate my phpBB installation into another app.
• Is there a system similar to Cutenews for ASP.NET that is free? All I want is to be able to post news that is integrated into my frontpage. I'm able to design the rest.
• Is Web.config analogous to .htaccess? If not, is there a directory-level configuration file? Becuase I need to be able to define custom 404, etc. files as well as disable directory listings for certain folders, etc. And I share hosting with my dad, so I'm a subdirectory of his site.
• Is there anything else I should know?

I'll be on another host so it won't be my server. — Ilyanep (Talk) 17:04, 17 June 2006 (UTC)

ASP.NET and PHP are two entirely different programming languages. phpBB and any mods you have for it will only run under a PHP interpreter. However, it is certainly possible to run PHP scripts under IIS [1], just like it's possible to run ASP.NET code under Apache [2]. So, you can either contact your hosting provider and see if they support PHP, or move to a different forum package written in .NET. (here are some possibilities)

If you can't use PHP and are looking for a Cutenews substitute, you might want to check Category:Content management systems.

From browsing Google for information about Web.config, it does seem to serve roughly the same purpose as .htaccess. However, I'm not all that familiar with ASP.NET myself, so you'll have to ask somebody else if you have any detailed questions about it.

Anyway, hope this helps! —David Wahler (talk) 18:15, 17 June 2006 (UTC)

web.config is kind of the same as .htaccess, in that you can define application settings, including 404s (for .net processed files only, for example .aspx, but *not* for .html, because that's served up by IIS directly). Directory listings are, again, controlled by IIS, not asp.net. Once IIS7 comes out then web.config will run the whole show. Whilst I don't know of a direct cutenews replacement [DasBlog] is a .net blogging engine that uses the file system, not a database. I guess it depends what bits of cutenews you want replicated. --Blowdart 23:36, 17 June 2006 (UTC)

Just something that can display news on the front page using a design template that I give it. And then I can do something like I do include(...); in PHP — Ilyanep (Talk) 03:51, 18 June 2006 (UTC)

I've not seen something like that. And include isn't part of asp.net, you would have to embedded it as a custom control. It doesn't look hard to code, so I'm sure there must be something out there. --Blowdart 15:44, 18 June 2006 (UTC)

Well, I understand there'll be some differences between PHP and ASP.NET, but I just don't want to have to get a package that essentially codes a whole website for me. — Ilyanep (Talk) 16:50, 18 June 2006 (UTC)

Use of cows milk vs. soya milk and toothpaste

Gillian McKeith states that cows milk is bad, and that you should only drink soya milk (which I have now been doing). She states that it forms some sort of mucus on the stomach lining and that is only for use on a calf (the milk). Is she right? Also, I have begun using normal toothpaste with whitening toothpaste, using the the normal first then the whitening. Will the two toothpastes cancel each other out? Thanks, Kilo-Lima|^(talk) 17:24, 17 June 2006 (UTC)

Whether cow's milk is "bad" you might like to consider that generations of people in many (though not all) cultures have been doing it for a very long time, and that our current expectations of longevity and health are mainly concerned with people who have been drinking it at some time. You might like to consider what actual or potential problems cow's milk is claimed to cause, and consider whether there is any evidence that this is in fact the case, perhaps by comparison with other cultures who don't drink cow's milk. I have never heard of this person, but I would also check for a secondary agenda, for example whether she is also an advocate of animal rights, who might consider it desirable to reduce the many animal deaths caused by drinking cow's milk, and if so, whether you share that agenda.

Some of the racial groups who have not been drinking cows milk for a long time (see Lactose_intolerance#Biology). Obviously if you are lactose intolerant then cows milk will be bad for you. -- Chris Q 09:24, 19 June 2006 (UTC)

For the second question, what do you mean by "cancel out"? Your teeth won't become dirty again, increasing tooth decay. Notinasnaid 17:51, 17 June 2006 (UTC)

If anything, using two toothpastes will only help. I don't see what's wrong with doing a double whitening though. ;o --Proficient 19:56, 17 June 2006 (UTC)

I'd be more worried about trusting someone who can only call herself a Doctor because of a "mail order" PHD from a non-accredited university (The American College of Nutrition). Please, consider your source. --Blowdart 20:15, 17 June 2006 (UTC)

Humph, that source does not know the difference between the UK and England, especially when Gillian McKeith is Scottish. Kilo-Lima|^(talk) 20:49, 17 June 2006 (UTC)

Are you complaining about the "London, England" bit on that page, because that's the only part I could see that you could make that comment about; and it is, obviously, accurate. --Blowdart 23:37, 17 June 2006 (UTC)

Ms McKeith is likely referring to rennet, since there is nothing else resembling her fanciful notion of a milk-specific "mucous lining" in calves. Soy milk as you buy it is a highly modified synthetic product. The rate of allergy is 5 to 20% (see [3]) and there is about a 50% cross-allergy with cows' milk. For young woman, skim milk would be the drink of choice, since soy contains neglible amounts of calcium. Apart from allergy differences, and the different fat compositions of the two products, there is no scientific proof that there is any benefit in drinking synthetic milk (see [4]). In the two books of this person that I have read, it is sometimes difficult to decide whether the writer is naively propagating untruths as valid science, or whether she is deliberately lying to make money. --Seejyb 09:30, 18 June 2006 (UTC)

I don't know about this "mucus-lining" stuff, but there is no evidence whatsoever that drinking milk decreases your risk of osteoporosis. Check this study by the Harvard School of Public Health out. Here's a quote from the conclusion of that study: "An adequate vitamin D intake is associated with a lower risk of osteoporotic hip fractures in postmenopausal women. Neither milk nor a high-calcium diet appears to reduce risk." It's an amazing dairy-industry conspiracy - somehow everyone thinks milk keeps your bones healthy, but it just doesn't seem to be true. And as for soy milk, I don't know what Seejyb means by "a highly modified synthetic product". It's made with a very old process developed in the 1st century BC (see Soy milk) It's basically, "grind the beans in water, then strain out the milk". --Bmk 13:56, 18 June 2006 (UTC)

An article about postmenopausal woman and calcium intake has absolutely no bearing on the recommendation that woman between puberty and 30 years of age should ensure that they have an adequate calcium and vitamin D intake as well as plenty of exercise. Inferring from such a study the recommended intake for young women in the window period when calcium intake does seem to make a difference to bone density for the rest of their life is irresponsible. How we get our calcium is irrelevant, and drinking three glasses of skimmed milk, or of soy milk to which calcium has had to be added (check the ingredients), or one and a half effervescent tablet in water probably makes little difference, except to the cost of the calcium. The soy bean, when not properly ("highly") processed contains significant levels of anti-nutritionals, as well as phyto-estrogens, which does seem to worry some scientists, since the levels of intake of soy products in the western world far exceeds that of the eastern countries where soy milk was traditionally consumed. As far as conspiracy theory goes, one has the uneasy feeling that the soy-derived ingredients in processed foods may eventually turn out to be not as harmless as claimed by the very powerful producing groups; they certainly spend huge amounts of money to promote it as "healthy" or "natural", which is patent rubbish - it is as natural as coffee, at best. In the east soy was not normally used as a basic food, the way the west does at the moment, so that the long-term effects are difficult to judge impartially. This is made more difficult by the fact that interested parties tend to promote only the research that benefits themselves (e.g. dairy producers vs soy bean producers) --Seejyb 01:12, 20 June 2006 (UTC)

Stable beer

Why is it that a full can of beer seems a lot more stable when upright than the same can empty. (And dont say because its not yet drunk! Ha Ha!)--Light current 18:32, 17 June 2006 (UTC)

It's more massive, so you have to hit it harder to knock it over. I don't know if you're aiming for something more profound...? Melchoir 18:48, 17 June 2006 (UTC)

I agree with Melchoir. If you have an empty can and a full can you can do a very simple experiment to see if there really is a difference: Push the very top of the empty can a tiny bit then let go. If it doesn't fall over, push the same place a little harder, let go, repeat until it falls over. Do the same again with a full can and see if you have to push them the same distance until they fall. Obviously you'll have to push the full can harder because it is more massive, so you'd want to pay attention to distance or angle and not force. 128.197.81.181 18:58, 17 June 2006 (UTC)

Wellll... it all depends on what one means by "more stable" anyway. The major difference between the two cases will be the force, not the angle, required to tip the can. Melchoir 19:10, 17 June 2006 (UTC)

Yeah but surely the centre of gravity is about the same in both cases?--Light current 19:02, 17 June 2006 (UTC)

Maybe, but the dynamics of a rigid body are determined by its mass and moment of inertia as well as its center of mass. Melchoir 19:06, 17 June 2006 (UTC)

Aha! I think you may have hit on it here! Its probably the moment of inertia that is much smaller when empty. But Im going to do a few experiments with a large number of full, then empty cans! How they get from full to empty, Ill leave to your imagination! %-)--Light current 19:15, 17 June 2006 (UTC)

Ah, the spirit of scientific inquiry! Melchoir 19:26, 17 June 2006 (UTC)

Yes: the suffering we have to endure in the persuit of knowledge! Yes! now the result of drinking the first can experiment! Comparing a full can with an empty one I noticed that the max tipping angle was approx the same for both. (say 30 deg from vert - I didnt actually measure it). But, if the cans are pushed below this critical angle and then released, the full can regains its upright position with no oscillation, whereas the empty can totters back and forth quite a few times before coming to rest. Any ideas on that one? Anyway, must get back to the lab! %-)--Light current 19:48, 17 June 2006 (UTC)

That's quite interesting. --Proficient 19:59, 17 June 2006 (UTC)

I guess the sloshing motion of the liquid inside helps to dissapate energy, plus other factors.HappyVR 20:07, 17 June 2006 (UTC)

Yesh-- Im coming to that conclushion myshelf!! %-)--Light current 20:14, 17 June 2006 (UTC)

Well, I agree, a full can of beer is much heavier, so you have to hit it harder to fall over. Also, a "full can of beer" isn't really full with beer, it always has some amount of air in it. – b_jonas 11:45, 23 June 2006 (UTC)

Also, in case of empty cans of beers, you're probably already sligtly under the influence of alcohol, so it's more likely that you accidenatlly tip it over. Also, if the can is empty, you're more likely to hit it angrily because you've run out of beer, while with a full can of beer, you take care not to knock it over because it would be a waste to spill the beer. – b_jonas 11:48, 23 June 2006 (UTC)

Building a bomb

I'm writing a fictional work (actually a Live action roleplaying game) in which somebody needs to build a simple bomb. According to time bomb, all one really needs is a battery, a watch, and some explosive material. What kind of explosive material? Where would a teenager on a colony on Triton (a new colony, not so different from the stereotypes of the American Old West) get such a thing? Like, if there's blasting crews on the colony, could he just lift some? What are the steps involved in making a bomb? I looked for instructions for building a simple bomb online, but it turns out it's less widely available than the scaremongers would have you think. And I don't need to actually do it myself, just describe in very rough terms what would be needed. moink 19:58, 17 June 2006 (UTC)

Maybe your character can steal some c-4 from a construction site as well as some blasting caps. --Proficient 20:01, 17 June 2006 (UTC)

Just make sure to explain that you character was well-trained in his former life, including Afghan, Irish, &c. references, and do not go into bomb making details : the reader shall know enough. --DLL 20:15, 17 June 2006 (UTC)

Hmmmm... I'm trying to make him a pretty lame loser character who doesn't really know what he's doing, but does some really basic research and figures out how to build a simple bomb. We're trying to make it hard for him to accomplish this, since it screws over the other characters pretty badly if he succeeds. moink 20:18, 17 June 2006 (UTC)

Are there weeds on this colony? He could use the ever popular weedkiller ( potassium chlorate or sodium chlorate) and sugar. Theresa Knott | Taste the Korn 20:43, 17 June 2006 (UTC)

If he's not looking to do too much damage, how about the ingredients in the Gunpowder article? --hydnjo talk 20:50, 17 June 2006 (UTC)

If they farm on this colony, perhaps they have ammonium nitrate around. Powerful, common, explosive. --Fastfission 05:13, 18 June 2006 (UTC)

According to Triton (moon), there is a lot of Ammonia present. Methane and Nitrogen are abundant in the atmosphere. If you have some water, I'm sure a chemist could whip something up for you. Dmn € Դմն 11:37, 18 June 2006 (UTC)

Does it have to be a bomb, or can it just be an explosion? Any fine powder should be very dangerous if it forms a mist. See Flour and Lycopodium. The lycopodium article has links to movies. --Kjoonlee 14:51, 18 June 2006 (UTC)

Well, just something that makes sense for my character to put together from a few different pieces and "set off" while he tries to get away. I think I'me going with C-4 and some wiring and a battery. moink 07:43, 19 June 2006 (UTC)

e-mail address harvesting?

I’ve been getting a lot of e-mails from various phony senders. They are without a subject line, have no content, and are addressed to “unlisted recipients.” What is going on? Is this some kind of e-mail harvesting, or maybe something worse? --Halcatalyst 20:46, 17 June 2006 (UTC)

Can you post the header? Theresa Knott | Taste the Korn 20:51, 17 June 2006 (UTC)

An example follows. --Halcatalyst 21:33, 17 June 2006 (UTC)

Received: from ams018.ftl.affinity.com 

(lvs00-fl-n18.ftl.affinity.com?[216.219.253.56](misconfigured sender))

          by sccqmxc94.asp.att.net (sccqmxc94) with ESMTP

          id <20060617165739q9400idrkae>; Sat, 17 Jun 2006 16:57:39 +0000

X-Originating-IP: [216.219.253.56]

Received: from cust_req_fwding (xxx@dendurent.com --> x.xxxxxxxxx@mchsi.com)

	by ams018.ftl.affinity.com id S1610159AbWFQQ5j for

	<x.xxxxxxxxx@mchsi.com>; Sat, 17 Jun 2006 12:57:39 -0400

Received: from [82.155.63.77] ([82.155.63.77]:61959 "HELO fdah.com")

	by ams018.ftl.affinity.com with SMTP id S1608422AbWFQQ5j;

	Sat, 17 Jun 2006 12:57:39 -0400

Message-Id: <S1608422AbWFQQ5j/20060617165739Z+11389@ams018.ftl.affinity.com>

From:	<xxxxxxxxx@fdah.com>

To:	unlisted-recipients:; (no To-header on input)

Date:	Sat, 17 Jun 2006 12:57:39 -0400

Durn. Can somebody tell me how to display this native? (with line breaks) Thanks. --Halcatalyst 21:38, 17 June 2006 (UTC)

Done. --cesarb 21:42, 17 June 2006 (UTC)

Thank you, CesarB! --12.217.186.109 02:34, 18 June 2006 (UTC)

It's very possible that the senders have their own SMTP servers, thereby eliminating the need to send a "To" address to another SMTP server and allowing them to directly interact with your ISP's mail servers without having to go through the regular process of specifying a "To" address to a third-party SMTP server. There are many possibilities; spammers use lots of different tricks. -- Daverocks (talk) 12:19, 18 June 2006 (UTC)

I wonder why theere is no content? Could the spammer be accomplishing something nevertheless? --Halcatalyst 13:14, 18 June 2006 (UTC)

I occasionally get spams with no content, which is rather confusing. A possibility that comes to mind is that they've set up a dummy email account to send from and they're tracking bounced emails to trim down their lists. 128.197.81.181 18:28, 18 June 2006 (UTC)

I suppose if they're sending out a couple million spams it might be useful to delete 300,000 (or even 50,000) bad addresses, especially if they have automated means to update the lists. But it's hard to imagine spammers being that concerned about efficiency. --Halcatalyst 19:18, 18 June 2006 (UTC)

I did hear that there are some spam networks who do this to wind up people who they discover trying to report their abuse (a lot of the bigger spam networks apparently buy thier own IP blocks on the black market so they can control the abuse contacts). Plugwash 00:50, 20 June 2006 (UTC)

Ergonomical Sleeping

If a futon is ergonimical to sleep on because of it's hardness, how egonomical to sleep on, is a camping mat on a hard floor? --Username132 (talk) 22:51, 17 June 2006 (UTC)

You seem to be assuming that futon has a more universal meaning than it actually does. In English, it seems to refer to any sort of folding bed, aka sofabed, though the original Japanese is something completely different and very specific. I slept on a very soft western futon during my university days.

Regardless, if I take your question to mean "If firm beds are considered ergonomic, is a camping mat on a hard floor equally so?" then I can explain why the answer is no. The futon in question (yours, I assume) isn't good for your back because it's hard, but because it only gives to a small degree (hence, firm), allowing your back to straighten instead of lying limp like it would on a very soft bed. A camping mat on a hard floor has no give whatsoever, and thus does not allow for natural body contours and ends up giving you stiff bones in the morning. As a person that rather enjoys sleeping on a hard floor, I can vouch that it is ergonomical to a certain degree, especially after long periods sleeping on a soft bed, but without a firm cushion underneath you quickly develop cricks in your neck and shoulders, and I guess that's why there are so many doctors who cure that sort of thing around these parts in Japan.  freshofftheufoΓΛĿЌ  05:28, 19 June 2006 (UTC)

June 18

Old Alcohol

I inherited a stock of alcohol in sealed bottles - over 30 to 40 years old. Is it safe to be drinking that? — Preceding unsigned comment added by 69.118.234.15 (talk • contribs) 21:14, 17 June 2006 (UTC)

In the case of wine, quite possibly, although it may have passed its best. Whisky (and whiskey) may be OK to drink too, but you may want to re-ask this question at the science reference desk, as they may be more able to help answer your question. EvocativeIntrigue _{TALK | EMAIL} 21:40, 17 June 2006 (UTC)

Moved from the Miscellaneous section by vibo56 ^talk.

If it's brandy in your bottles, then it will probably be very good indeed. --Kurt Shaped Box 00:26, 18 June 2006 (UTC)

The alcohol you are referring to is ethanol, right? Otherwise, you probably wouldn't want to drink it :-) ...

If it is wine or anything stronger, I think it would be safe to taste it. And if the taste's ok, I think it would be safe to drink it. But to be on the safe side, wait a couple of days until other contributors have had their say! --vibo56 ^talk 00:19, 18 June 2006 (UTC)

Or send another contributor the alcohol and see if they survive after a few days. --M1ss1ontomars2k4 ^{(T | C | @)} 00:20, 18 June 2006 (UTC)

And if they die, the traditional rule for food-tasters applies. They get a cemetery or a crematorium named after them. (lol). JackofOz 00:35, 18 June 2006 (UTC)

Well, depending on what sort of beverage we are talking about, volunteers shouldn't be that hard to find... :-) --vibo56 ^talk 00:42, 18 June 2006 (UTC)

The thing is, if the yeast which creates the alcohol is still in there, it can take the alcohol and further convert it to Ethyl Aldehyde, and then to Acetic Acid (vinegar). Usually the yeast is removed to prevent his from happening, and with high content spirits the alcohol content can get to toxic levels for the yeast.

My guess is that it would be safe, but like was said above, it could just taste awful. —Mets501 (talk) 02:29, 18 June 2006 (UTC)

Well, you shouldn't rule out the thought of selling them. Since they are so old, you might get a good deal if you can -prove- that they are 30 to 40 years old. --Proficient 14:40, 18 June 2006 (UTC)

Even better, drink it, buy something cheap to refill the bottles, then sell it as well. Black Carrot 21:52, 18 June 2006 (UTC)

My budgerigar's eyelids

This is something that I first noticed years ago, with my very first pet budgie but completely forgot about until I read all the budgie-related questions on here. Is there any particular reason that when a budgie blinks, its bottom eyelid moves up to meet the top, as opposed to the top eyelid moving down to meet the bottom, as in humans? Is there any particular advantage to this configuration, or is it just a case of two very different species evolving from two very different evolutionary lines and arriving at different solutions for the same problem? --Kurt Shaped Box 00:50, 18 June 2006 (UTC)

Are you sure this isn't a third, inner eyelid you are seeing, in addition to the normal eyelids ? Cats have this, too, and I assume it's useful for removing debris (like fur, in the case of a cat) from the eyeball. StuRat 23:51, 18 June 2006 (UTC)

Na. It's definitely his bottom eyelid - I've been sat watching him for the past ten minutes. When he blinks, the bottom lid moves up to meet the top one. Go figure. --Kurt Shaped Box 11:25, 19 June 2006 (UTC)

Although there may be an advantage, I would chalk it up to the vagaries of evolution. --Ginkgo100 ^{talk · contribs} 20:07, 21 June 2006 (UTC)

Perhaps there is pressure from predation that pushed evolution in this direction. I'm thinking they may have a better view of predators from above with this arrangement. Are all birds eyelids like this, I wonder? —Bradley 22:36, 22 June 2006 (UTC)

How does my Electric toothbrush recharge itself?

I've got a Braun toothbrush which has a solid plastic casing. I recharge the toothbrush by placing it on a small recharging unit that also has a solid plastic casing. The unit is plugged into the mains, but how does the toothbrush recharge when there are no metal contact points on the charger or the toothbrush?

Psychonaut3000 01:44, 18 June 2006 (UTC)

Assuming you have't missed the metal contacts I'd assume through electromagnetic induction. A coil of wire with an oscillating (AC possibly highfrequency) current in it would induce an oscillating electric current in a pickup located inside the tootbrush. This could be used to charge a battery. Sorry I can't find a good page to explain the process..HappyVR 01:54, 18 June 2006 (UTC)

Yes as described here. Also the early models of implanted artificial pacemakers used this method of recharging its batteries. --hydnjo talk 12:08, 18 June 2006 (UTC)

You can test this by dangling a small piece of steel inside the charging socket: the metal ferrule on a pencil works well, as should a small screwdriver. If you can feel a vibration, it uses magnetic induction. --Serie 20:06, 19 June 2006 (UTC)

HIV Transfer

If I have a small cut on my penis, and I am getting a blowjob from someone that has HIV or AIDS, will I get HIV? I was reading an article and it mentioned that the HIV virus is in saliva also, thanks

There is risk, but it does not guarantee infection. Any body fluid exchange can carry the virus, but the operative word is CAN, not for certian. Also consider that the virus is fairly fragile, and does not survive very long outside the body. I would strongly reccomend you get yourself checked, this virus is pretty ugly once it gets a hold of you.

See #HIV. Conscious 05:07, 18 June 2006 (UTC)

You shouldn't risk it. --Proficient 14:47, 18 June 2006 (UTC)

Regardless of the cut, you shouldn't risk it. Black Carrot 21:50, 18 June 2006 (UTC)

And you should shave more carefully. - Nunh-huh 11:24, 19 June 2006 (UTC)

PNG graphics transparency

I've noticed that some PNG graphics on Wikipedia that are shown with a transparent background within the article actually have a blueish background. Here's an example:

In the article PNG this same image has a transparent background.

Why does this happen? How do I make the background display as transparent?--Anakata 02:15, 18 June 2006 (UTC)

Internet Explorer cannot handle transparant PNG images, and often displays them (on Wikipedia) with a blue background. You could try using Mozilla Firefox; that will fix the problem. —Mets501 (talk) 02:24, 18 June 2006 (UTC)

I recommend Firefox as well, but here's a fix for MSIE users who can't switch: Wikipedia:Tools#Internet_Explorer_alpha_transparency. It isn't failsafe, though, so beware. --Kjoonlee 12:41, 18 June 2006 (UTC)

IE will handle transparency in PNGs, but only as one bit transparency (i.e. transparent or opaque), IE has no support for optional alpha channels, thus remains within the PNG spec. The PNGs are broken if they don't include the transparency map with an alpha channel, as far as the spec says. For what it's worth, IE7 seems to handle non-conformant PNGs much better than IE6 did and, of course, FireFox attempts to handle even extremely poorly formed PNGs (which may be a security flaw as libpng comes under attack) Wayne Hardman

Can you explain me the types of sugar?

I want to know everything about types of sugar like table sugar,milk sugar,starch sugar and fruit sugar. Please help me with this topic.--59.144.254.49 03:41, 18 June 2006 (UTC)

See sugar and carbohydrate. They will certainly point you to sucrose, lactose, amylose, and fructose, the sugars to which you may be referring. Cheers, David Iberri (talk) 03:45, 18 June 2006 (UTC)

Web based file sharing

I've recently been asked by an online group in which I'm active if I could establish some sort of web-based file sharing tool... Pictures, audio files, and possible applications. There are several groupware packages that incorporate some type of upload/download for members but, along with that functionality, one is bombarded with features that are not, in this case, needed.

Is there a web-based file sharing package (for linux?) that might work for this group? I've read through File sharing but the article is concerned mostly with P2P stuff. Thanks so much for any guidance you guys (and gals) might be able to provide! --Chiacomo ^talk 04:45, 18 June 2006 (UTC)

Have you considered an FTP server? –Mysid^(t) 07:52, 18 June 2006 (UTC)

I usually use FTP for large person to person transfers. However in this case, it sounds to me like given that there are a fair number of participants so I wonder if something like a members only Direct Connect server. Chiacomo, I would suggest you read up on copyright law however. You could be held responsible if people misuse your server to distribute copyrighted audio files and applications without permission from the copyright holder. Nil Einne 15:15, 21 June 2006 (UTC)

MILF!

Why is it that some teenage boys/young men are attracted exclusively to women in their 40s? Is there a scientific/evolutionary explanation for this? In terms of reproduction, this would seem to be counterproductive (without trying to sound too veterinary, women of that age are past their prime when it comes to breeding). --84.65.31.248 05:48, 18 June 2006 (UTC)

I'm not sure what you mean by "exclusively". I doubt young/men boys are alone in their lust for women in their 40s (one would think their husbands might also have a sexual interest in them). Nor are 40 year old women the only object of teenage boys desire (otherwise teenage girls wouldn't have many boyfriends). That notwithstanding, its an interesting question. From a psychosexual point of view, one could argue that teenage boys are experiencing the junction between cutting their ties to the primary female in their life (their mother) and experiencing sexual feelings for the first time towards another woman. Thus an older woman can fulfil both their need for a caring, maternal relationship and a sexual relationship. That someone could fulfil both roles could manifest as a strong sexual attraction in a young males. I'm sure Freud would having something to say about that. Rockpocket 08:05, 18 June 2006 (UTC)

Maybe I'm misremembering my youth, but I seem to recall that teenage boys lust after anything with two legs and a pulse. That said, Rockpocket is probably on to something with his reference to Freud. There are also undoubtedly teenage boys who find that most girls their own age are immature, just like (many more) teenage girls find boys their own age immature. --Robert Merkel 11:37, 18 June 2006 (UTC)

I think big tits have something to do with it?HappyVR 13:17, 18 June 2006 (UTC)

Well, make a decision. Do you think that or do you not? ;) My opinion more or less echoes theirs, without the Freudian part. Evolution probably has little to do with it. Black Carrot 21:48, 18 June 2006 (UTC)

On the question of evolution, it may have something to do with the female reproductive peak much later in life (I think 35yrs. is typically cited,) so perhaps the male evolutionary response is to seek out those females most likely to bear children?

The thing about the sexual peak at 35 doesn't jive with evolutionary/reproductive success theories, because women begin to lose fertility in their late 20s or early 30s. A much more documented phenomenon is of older men seeking out women in their early 20s, because these women are more fertile. At 35, the risk is much higher for pregnancy complications and birth defects. My pet ideas:

1) When (straight) teenage boys first become attracted to women, some of them might find themselves more attracted to "unobtainable women" such as celebrities, models, and older women, because there isn't any real chance of having to interact with them. They can avoid the fear of being rejected or humiliated, because they're obviously not going to hit on (or get hit on by) their friend's mom.

2) Teenage girls are just as nervous/self-conscious as teenage boys, while older women are generally much more confident and comfortable with their sexuality. Confidence is a huge turn-on for most people. TheSPY 15:07, 19 June 2006 (UTC)

Oedipus complex, anyone? --M1ss1ontomars2k4 ^{(T | C | @)} 05:02, 20 June 2006 (UTC)

Some people are weird, some people like older partners, some younger, some much younger, some too young, but those people go to jail. Philc _T^E_C^I 22:23, 20 June 2006 (UTC)

I agree with others that the exclusively part is a bit dubious. I'm sure there are some who are exclusively but my expectation is that most visitors of sites like MILF are not exclusively attracted to older women but can find older women a turn on in some circumstances. I suspect a number of the suggestions are part of the reason (freudian issues, confidence etc). I also expect experience has something to do with it. There is the expectation that older women are more 'sexually experienced' which many may find a turn on. There is also likely a vast difference between the average personality of a teenage female and a significantly older partner. I'm not talking about experience or confidence here but I would assume an older women, especially one that is interested in a romantic relationship with a teenage boy is far less liekly to have hang ups about sexual intercourse and is not going to make the kind of financial and social demans that a teenage girl would. All in all, I guess what I'm saying is it's a rather complicated question and there is no one reason Nil Einne 15:11, 21 June 2006 (UTC)

Diffusion and Osmosis

What does "concentration gradient" and "chemical potential" mean in the context of diffusion?

I am often confused by the idea of "diffusion". THe following is my idea of what's diffusion?

"The dispersion of random moving particles from high concentration to low concentration"

For the definition of osmosis:

"The diffusion of water from low concentration to high concentration"

Please correct any wrong ideas thank you!

Concentration gradient is the rate of change in the concentration of a substance along a given direction. In the context of diffusion, say you have a region of high concentration of a substance and a region of low concentration of the substance. As you move from the region of high concentration to the region of low concentration, the concentration changes gradually. Concentration gradient in this context is a measure of how rapidly the concentration changes as you move from one region to another.

In osmosis, you have one or more dissolved substances (solutes) dissolved in a solvent (of which water is a common example). Osmosis is the diffusion of solvent across a semi-permeable barrier from a region of low solute concentration to a region of high solute concentration. Osmoisis is a form of diffusion. (In the definition of osmosis you gave, "concentration" is that of the solute(s), NOT of the solvent)--72.78.101.61 12:52, 18 June 2006 (UTC)

Why does the particles MUST move from high to low concentraiton?

The net movement of particles from a region of high concentration to a region of low concentration is the result of the movement of many individual particles. For simplicity, imagine that there is a (real or imaginary) boundary separating the two regions and assume that particles are equally free to cross the boundary in either direction. In order for a particle to cross from side A of the boundary to side B, there first needs to be a particle on side A (near the boundary). If there's a higher concentration of particles on side A (than side B), probability dictates that the expected number of crossings from side A to side B is higher than in the reverse direction. Note that the net flow of particles is a statistical average. Particles cross the boundary in both directions. It's just that there are more crossings in one direction than in the other.--72.78.101.61 14:50, 18 June 2006 (UTC)

They don't have to, its perfectly possible that they don't atoms molecules are constantly moving about, they go wherever, but it is more likely that they will go to a lower concentration. Philc _T^E_C^I 22:21, 20 June 2006 (UTC)

Case in e-mail addresses

I've looked at the e-mail address article, but it doesn't seem to be clear on whether upper-case and lower-case letters are treated as different characters in e-mail addresses. Either they are or someone doesn't want to talk to me- which is it? Henry^Flower 08:16, 18 June 2006 (UTC)

It depends on the software which receives and routes the e-mail. There are many different software solutions for this, and some will distinguish between upper and lower case in addresses. However, upper and lower case unaccented Latin characters should not be significant in the domain name (that is, the part after the @ sign) according to the rules of DNS; however it remains possible that some e-mail software will still care. For this reason, best practice in reproducing an e-mail address is to use exactly the case originally given. Notinasnaid 08:32, 18 June 2006 (UTC)

Thanks! I'll try some permutations. Henry^Flower 08:35, 18 June 2006 (UTC)

Also, some web-based email services like Gmail and Hotmail force all usernames to be lower-case, which helps. But with email addresses residing with ISPs, their policies all vary. -- Daverocks (talk) 12:35, 18 June 2006 (UTC)

See e-mail address. The local part of the address is case-sensitive, the domain name is case-insensitive. However, not all e-mail software properly implements RFC 2821. Gdr 19:09, 18 June 2006 (UTC)

Actually my reading is that it must be treated as case sensitive but use of case sensitivity is discouraged. I would guess this means there is nothing wrong with the common practice whereby case is preserved but ignored. I.E. BillG@.... is treated as the same thing as billg@. Personally, I know my ISP and most other ISPs have done likewise (i.e. ignored case). Nil Einne 14:19, 21 June 2006 (UTC)

Health

What can cause a cancerous tumore of the brain?

Try the article on brain tumor and google. Weregerbil 11:21, 18 June 2006 (UTC)

Reading too many Wikipedia articles is the cause. :-) StuRat 23:44, 18 June 2006 (UTC)

drugs

1.What are the functions of drugs? 2.What are the helpful and harmful benefits of drugs to people?

Try the article on drugs and the articles on medication and recreational drugs linked therein. Also google is your friend. After doing some research on your own please ask specific questions on anything you can't find on Wikipeda and the net. Weregerbil 11:23, 18 June 2006 (UTC)

Some of them make you better if you take the right amount. Some of them make you sick if you take the wrong amount. --Kurt Shaped Box 11:30, 18 June 2006 (UTC)

I'd say they all make you better if you take the right amount, and make you sick if you take the wrong amount. In some cases the right amount would be "none", but in the words of ... hell, I don't even know ... "Of course too much is bad for you - that's what too much means!" Confusing Manifestation 09:30, 19 June 2006 (UTC)

Turkish spider

Does anyone know what kind of spider this is? I took these pictures in southern Turkey, near the village of Aglasun. Many thanks, pjd 11:50, 18 June 2006 (UTC)

I'm no expert, but the head reminds me of windscorpions. --Kjoonlee 13:26, 18 June 2006 (UTC)

Many thanks Kjoonlee, I just read the article and you are probably right. The eyes on top of the head, the pincer 'jaws' and the long pedipalps 'giving the appearance of two extra legs' all point to a windscorpion. pjd 14:20, 18 June 2006 (UTC)

biology question.

Potato plants bear seeds and flowers yet they never grow from their seeds.Why?--59.144.242.244 12:19, 18 June 2006 (UTC)

Some varieties of potato produce seed, some don't. The ones that do can be grown from seed. It's just that they germinate slowly, the plant grows smaller, and produces less harvest than potatos grown from tubers (the tuber has all that easy-to-use energy that gives young plants a jump start on life.) So commercial production starts from tubers. Potatos are occasionally grown from seed by researchers when they try to produce new varieties by cross pollination. Weregerbil 13:07, 18 June 2006 (UTC)

Non-microwavable security devices

OK, so i've just been to the supermarket and bought some razor blades. They come fully equipped with a sticker saying: "This product contains a non-microwavable security device". Presumably this is some kind of RFID tag. My questions are:

1) Is a RFID tag any more or less microwavable than a razor blade? The razor blades don't come with a 'Don't put me in the microwave' warning.

2) Why would you want to microwave a packet of razor blades anyway (unless you were into making sparks?)

--Chris 12:53, 18 June 2006 (UTC)

Presumably that's a safety warning against attempts to destroy any RFID tags embedded in the product by "cooking" the product in a microwave.---72.78.101.61 13:09, 18 June 2006 (UTC)

It sounds like a dare to me!

It's probably a standard label placed on a number of items, some of which happen to already have metal components. Black Carrot 21:44, 18 June 2006 (UTC)

I think the point of the warning is that you should not microwave it, not that microwaving would have no effect. Hence not a dare, but a warning of possible sparks—i.e., this packaging contains hidden metal. —Bradley 23:29, 19 June 2006 (UTC)

razor blades are no fun. you should try putting light bulbs in the microwave. that's fun! (serious) VdSV9•♫ 01:33, 20 June 2006 (UTC)

They've actually covered this in the Feedback column of the New Scientist - why would you want to microwave razor blades!? Or an RFID tag, for that matter? --Jrothwell 16:39, 20 June 2006 (UTC)

• it';s just a suggested guidline, like when they tell you your signature is horrifyingly long, it's just a guidline to change it--Bee(y)^Ti 01:48, 21 June 2006 (UTC)

Firefox problem

Hello. I am trying to download Google's notebook, and I keep getting this darn porblem about it not letting me install the software. Then, below the address bar, it sasys "Software installation is currently disables. Click Edit Options... to enable it and try again." I then added "tools.google.com" to the allow list, but it still doesn't let me download it. I followed all of the instructions on the page that helps you, but to no avail. Any ideas? Thanks a lot. Iolakana|^(talk) 16:22, 18 June 2006 (UTC)

it's unlikely, but could be a profile problem. Try removing your Firefox profile and starting again (it'll remove all your cache/bookmarks, though). Heres how; Close all Firefox windows and make sure the firefox process is stopped. Assuming you're using windows go Start -> Run "Firefox.exe -Profilemanager" (if you're not running Windows you can use the same option through command etc), delete your current profile, then create a new one, then restart Firefox. There's a chance that might fix it as it could be due to some mismatching. I suggest you try this as a last resort only though. -Benbread 21:55, 18 June 2006 (UTC)

You might have set your security options to disable all software installs, no matter what the website. --M1ss1ontomars2k4 ^{(T | C | @)} 05:00, 20 June 2006 (UTC)

You mean Google SketchUp? I am not aware of a notebook. — The Mac Davis] ⌇☢ ญƛ. 03:34, 21 June 2006 (UTC)

Scientific Reviews

Why do scientists write reviews and how long does it take?

What types of reviews are you talking about? Book reviews, article reviews, peer review? (Movie reviews?) The one type of review which is most associated with scientists is the peer review, take a look at our article on that. As for how long it takes, surely it depends on the subject matter and the scientist. --Fastfission 18:22, 18 June 2006 (UTC)

In my mind the sort of review most associated with scientists is a review article. Research articles describe results from a particular experiment or a set of experiments. Review articles, on the other hand, describe the results from a set of research articles, attempting to unify various results with a simpler explanation, usually trying to argue that the various results support the author's personal theories. How long it takes depends on a lot of things: how well the author knows the literature, the intended length of the review/amoung of content to be included, number of authors writing the review, number of hours per day spent writing, etc, so it's hard to give a good answer. Hope that helps. 128.197.81.181 18:39, 18 June 2006 (UTC)

Yeah, I was referring to review articles (cf. movie reviews!) Who funds the scientist writing a review article? --Username132 (talk) 20:59, 18 June 2006 (UTC)

I'm pretty sure whomever is funding the person's work is funding any review articles the scientist writes as well. Unlike actual experiments which can require specific funding for equipment, lab workers, chemicals, etc., writing a review paper really only requires time, so there isn't really a need to request extra funding. 65.96.221.107 22:59, 18 June 2006 (UTC)

I have written a number of reviews in my time and, in my experience, they can take anything from 10 hours to 50 hours of work depending on length and how much i know about the relevent primary literature off hand. I often get a student or post-doc to write a draft first, so that cuts down on my time. In most cases there is no payment for writing the review (though occasionally there may be a token fee paid if it is an invited review) so my time is paid for off research or core grants. Though, as is the case with most scientists, grant, review and paper writing tends to happen on your own time (at weekends and evenings). Rockpocket 02:49, 19 June 2006 (UTC)

Scientific reviewers are almost always benevolent, unpaid. It's considered 'part of the job': you review papers for others, and expect others to return the favor, although this is done anonymously, so you never know who comments on your own work. In addition to the factors already listed, the total time it takes to get the reviews back also depends on the willingness of the Editor responsible for the publication to chase reviewers, on the professionalism of the reviewer(s), on the efficiency of the secretarial assistants, etc. Sometimes, the preparation of a special issue on a particular topic may lead to further delays in the review process if the Editor insists in synchronizing the handling of a number of papers, or if multiple papers are sent to the same reviewer(s). For the most responsive journals, you may expect to hear about your paper in a matter of one to a few months. In the worst cases, you may have to wait for a year or more. --Michel M Verstraete 23:37, 19 June 2006 (UTC)

CSS DIV issue

I've been trying to make a workmanlike image map using primarily CSS. After scouring Google for examples of how to do this, I've ended up with what seems to be a relatively basic approach. It almost works...

Basically, I have a menu image with a number of places to click on little links to other pages. The basic CSS behind it is as follows:

#headermenu { background: url("header-menu.jpg") no-repeat right; background-color: #000000; height: 25px; width: 100%; } 

#headermenu .aboutbtn { 
	border: 1px solid red;
	position: relative; 
	left: 440px; 
	width: 51px; 
	top: 2px; 
	height: 18px;
}

#headermenu .archivebtn { 
	border: 1px solid red;
	position: relative; 
	top: -18px; 
	left: 518px; 
	width: 66px; 
	height: 18px;
}

#headermenu .linksbtn { 
	border: 1px solid red;
	position: relative; 
	top: -38px; 
	left: 613px; 
	width: 48px; 
	height: 18px;
}

#headermenu .contactbtn { 
	border: 1px solid red;
	position: relative; 
	top: -58px; 
	left: 689px; 
	width: 64px; 
	height: 18px;
}

Pretty straightforward, yes? (I know it would be more straightforward if the positions were "absolute" but that doesn't work with the arrangement I have). The little red borders are just there so I can see where the links are set for at the moment.

The HTML which uses this looks like so:

<div id="headermenu">
	<a href="about"><div class="aboutbtn"></div ></a>
	<a href="archive"><div class="archivebtn"></div></a>
	<a href="links"><div class="linksbtn"></div></a>
	<a href="contact"><div class="contactbtn"></div></a>
</div>

Now this all comes up perfectly on the screen. The menu image is there, the links are in the right place, they do what they are supposed to do.

Except that the entire menu image itself is also a link, and goes to wherever the first button is set to go. This is not what I want it to do, nor is it what it seems to me that it should do (I haven't told the entire headermenu to be a link, just the div inside it... right?).

What could be causing this? It happens in all browsers I try it on. I find it perplexing because I can't see why it thinks it should do this, much less how to prevent it from doing it. --Fastfission 18:31, 18 June 2006 (UTC)

The HTML 4.01 Transitional DTD says: <!ELEMENT A - - (%inline;)* -(A) -- anchor --> I don't think you're allowed to put <div> inside <a>, because <div> is a block-level element, not an inline-level element. --Kjoonlee 18:54, 18 June 2006 (UTC)

Have you tried using <span>, the inline equivalent of <div>? --Kjoonlee 18:57, 18 June 2006 (UTC)

Turning the <div class="aboutbtn"> into <span class="aboutbtn"> made it so that the links don't appear at all. :-( CSS sometimes makes me sad... --Fastfission 19:02, 18 June 2006 (UTC)

Oops. I didn't expect that.

<div id="headermenu">
        <a href="about.htm"><img src="about.png" alt="about" class="aboutbtn"></a>
        <a href="archive.htm"><img src="archive.png" alt="archive" class="archivebtn"></a>
        <a href="links.htm"><img src="links.png" alt="links" class="linksbtn"></a>
        <a href="contact.htm"><img src="contact.png" alt="contact" class="contactbtn"></a>
</div>

How does this work? You need something inside the anchor if you want to click it. --Kjoonlee 05:02, 19 June 2006 (UTC)

Well, I could try that as a last resort, but it's not at all what I'm trying to do (I was trying to make an imagemap, i.e. links positioned in regions on an image)... --Fastfission 13:56, 19 June 2006 (UTC)

Here's something else that drives me bonkers. If I use SPAN and make the positions ABSOLUTE, then it works. However it won't (unsurprisingly) stay "glued" to the menu image (If I resize the window, they are not in sync at all). If I make the positions RELATIVE then the links don't show up at all. What the heck? --Fastfission 14:37, 19 June 2006 (UTC)

OK, I got it to work with the original code, more or less. A lot of my troubles were stemming from the fact that I termined by curly bracket on the line before the CSS posted here with a semicolon (habit), which apparently made all hell break loose. But once I removed that semicolon, it works fine. Sigh... --Fastfission 15:08, 19 June 2006 (UTC)

Blade Sharpening

In the film 'the colour purple', there is a lady that sharpens a razor on what appears to be a leather strap. How is a leather strap able to sharpen a metal razor and is this method still applicable to modern-day blades? --Username132 (talk) 20:54, 18 June 2006 (UTC)

You might be interested in our articles at straight razor and strop. — Lomn | Talk 21:27, 18 June 2006 (UTC)

On the other hand, you might not. Neither one answers your question. - Nunh-huh 23:44, 18 June 2006 (UTC)

As I understand it (i.e., in my limited understanding), strops aren't very good at sharpening, but they're good enough that it can stretch out the time needed between "real" sharpenings. If you think of the use of a razor, the thinnest parts have a tendency to "fold over" back in the opposite direction of the razor's use. This "folding over" makes the edge less keen. A few strokes on the strop helps reverse this and tide you over until the razor can be resharpened with a more efficient tool. - Nunh-huh 23:48, 18 June 2006 (UTC)

Leather strops are used with an abrasive polish (absorbed by the leather). - Nunh-huh 03:29, 19 June 2006 (UTC)

To explain his folding in a different way is that every knife, whether serrated or not, has thousands of little tiny teeth on the blade. Each time you cut, the knife's teeth ribbons bend to the sides. When you sharpen, you try and bend the teeth ribbons back all pointing the same way. — The Mac Davis] ⌇☢ ญƛ.

I don't remember that part of the movie (i barely remember seeing it at all.) But, any good Boy Scout knows that an essential part of knife sharpening (for wood carving purposes, at least) is use of a 'slipstick' which is essentially a piece of leather bound to a small plank of wood. It is used after the knife has been sharpened on a stone, to break away the fine edge on the blade left from the stone.

What!!! you can't be using a slipstick for sharpening!!! — The Mac Davis] ⌇☢ ญƛ. 03:31, 21 June 2006 (UTC)

Static On My Person

If my skin is non-conductive at low voltages then how does touching an earthed object with one hand remove static from my entire body? --Username132 (talk) 22:18, 18 June 2006 (UTC)

For one thing, "static" is the same as high voltage. Second, your skin isn't non-conductive. Instead, skin is both a bad insulator 'and' a bad conductor. It's full of moisture, particularly salt water, and is backed up by very wet and salty meat. In other words, it's a resistor. Touch your finger to the leads of an ohmmeter, and you'll see a reading somewhere between thousands of ohms and hundreds of thousand of ohms. If your skin was made of metal, then it would only take a few nanoseconds in order to discharge your entire body by touching Ground. Instead it takes many microseconds: it's still almost "instant," yet it's much slower than what metal would do. --Wjbeaty 22:32, 18 June 2006 (UTC)

So what sort of features of a person would mean they would have a very high/very low resistance? I have a friend who can literally touch one finger to a wire and then touch another finger (on his other hand) to the other and of a wire and be able to complete the circuit, on voltages < 9v! We call him the human wire... -Benbread 22:42, 18 June 2006 (UTC)

I am a person with a low (electrical) resistance. This is becasue I sweat profusely on the palms (and feet). When I touch the leads of the ohmmeter, I registered the lowest resistance in my class (I don't remember how much). Even though I don't sweat all over my body, I suppose that the sweat on my palms makes a very good contact with the leads, thus allowing electric current to pass easily. The worst part was that I frequently got small electric shocks from the bare wires of the 5V circuits we used to build in our electronics labs. I even used to feel the tingle if I put my fingers across a conducting diode (~ 0.7V). It is a different issue that many of my friends didn't believe me. -- Wikicheng 04:14, 19 June 2006 (UTC)

This is the same thing the E-meter does in Scientology. The conduction at the surface, i.e. how much you're sweating, is very important in the total resistance, which is how the E-meter does a good job of measuring stress. (or engrams I guess, depending on your beliefs). I believe one of the measurements of a polygraph may operate on a similar principle. moink 07:18, 19 June 2006 (UTC)

Please help me identify this insect

Unknown insect

I found this very odd insect in my parents house, they live on the north south end of Vancouver Island in Sidney, British Columbia.

I have never seen such an insect around here before and was wondering if anybody could identify it. It is about 1 inch long and was sitting high on a wall near the ceiling. HighInBC 23:42, 18 June 2006 (UTC)

Check the Weevil article. Since Sidney is on the ferry route there is a good chance it hitched a ride. Very common in the US. ...IMHO (Talk) 06:52, 19 June 2006 (UTC)

Just as an aside, Sidney is nowhere near the North end of Vancouver Island. It's at the North tip of a small peninsula near the South of the island. moink 07:15, 19 June 2006 (UTC)

Oops, I got the words mixed up. Thanks for the info! HighInBC 12:32, 19 June 2006 (UTC)

June 19

Arrowroot Flour

I have ground arrowroot and I have flour - in what ratio do I mix these to make 'arrowroot flour'? --Username132 (talk) 02:32, 19 June 2006 (UTC)

Um, I think "arrowroot flour" simply means flour made from arrowroot, not arrowroot mixed with wheat or whatever. So I'd say 100:0. Depends what you want to use it for, though. —Keenan Pepper 03:08, 19 June 2006 (UTC)

Keep in mind that what is sold in the store as "arrowroot flour" is often not real arrowroot (see note in that article). 128.197.81.181 18:41, 19 June 2006 (UTC)

Is the Wikipedia being censored by the academic guild?

This may seem like a rare problem but I have noticed that some scientific and technical articles are being edited to prevent other users from obtaining a complete and full comprehension of a topic in the same manner as a member of a trade or artisan guild might try to hide techniques or methods or understanding of what the topic actually involves. Such articles are only permitted to have a highly technical version or explanation of the process being presented in the same manner as a tradesman or artisan might withhold simple explanations from a patron for the sole purpose of mystifying the topic and keeping the patron from knowing “too much.” What is the Wikipedia policy on such behavior where simple and accurate explanations are continuously deleted from an article on the false pretense that the article is not about the example although the example fully clarifies the topic? ...IMHO (Talk) 04:36, 19 June 2006 (UTC)

Examples?

Yes, I'd like to see an example too. Of course there's a lot of information difficult for "outsiders" to understand in the 'pedia, but generally it's because of the persons lack of concern for readers with a very low level of understanding. Nothing of what I have seen suggests censorship.  freshofftheufoΓΛĿЌ  04:59, 19 June 2006 (UTC)

I would hope not but then suppose all sysops were also members of the telecom brotherhood or union and certain accurate but simplified technical disclosures were routinely deleted? Would this not make you a bit suspicous? As for examples. Put the Half-life article on your watch list and see over a period of time what conclusion you might reach. ...IMHO (Talk) 05:23, 19 June 2006 (UTC)

I'd say sometimes the medical articles are written in unnecessarily technical language. But I think this is just health professionals failing to consider their audience when writing here rather than a deliberate attempt to obscure. See Hanlon's Razor. There's also the fact that writing both accessibly and accurately about technical is a very difficult skill.

I understand the difficulty for any individual to step far enough away from the field of expertise to see it clearly form a layman's pov but that is why we participate in the Wikipedia in the first place. My concern is that when such experts guard an article with such jealously that any user who is able to bridge the gap between the experts and the layman is prevented from adding simple but accurate explanations. ...IMHO (Talk) 06:30, 19 June 2006 (UTC)

I do think there's scope for stronger attention to be paid to Wikipedia:Explain jargon.--Robert Merkel 05:31, 19 June 2006 (UTC)

In this regard you must unfortunately include mathematical symbols and representations which more often than not require examples of computer code and data in order that the jargon be explained. ...IMHO (Talk) 06:33, 19 June 2006 (UTC)

Perhaps we don't want to sit around and watch the half-life article—did you choose this article as a pun? Why don't you find an example of an edit that removed factually accurate information that made the article harder to understand? My guess would be that incorrect analogies are removed from articles by people who have a definite understanding of the material and that you are simply paranoid. Also, just because a statement is understandable doesn't mean it is true. —Bradley 23:16, 19 June 2006 (UTC)

To have coordinated censorship you'd need coordination among academics in the first place. Which generally does not exist. But as a form of systemic bias, I think it is true that sometimes certain lesser-known topics get monopolized by those who know a lot about them but are not good at explaining it. The better known a topic is, the less likely this can last for long. But there are some articles which reflect a total lack of consideration for the layman (even something as non-technical and narrative-based as our biography of Franz Boas, which is about 3X too long, suffers from this). --Fastfission 13:54, 19 June 2006 (UTC)

I think that in many cases, the technical jargon is used because it saves time--it describes something specific in a way that is easily recognized by people in the field, while using a minimum amount of language. The challenge for Wikipedia, or any widely-used reference source, is how satisfy both "expert" users as well as the public at large. Experts don't want to plod through simplified explanations of what they already know; novices don't want to be frustrated by language they don't understand.

Going back to your question, I believe that there's a policy or guideline or something about how Wikipedia editors should not act as if they "own" a given article. Wikipedia is about reaching consensus and allowing many people to do their bit towards improving an article. --Tachikoma 14:06, 19 June 2006 (UTC)

The problem with reaching consensus is that there is a small group of committed academics who jealously guards some articles, immediately removing any attempt to make them accessible to the general public (which, while far more numerous, lacks the same level of commitment and is thus easily scared off by such actions). The only way I was able to find around this problem was to create a separate article for laymen. For example, the article Boolean algebra suffered from this problem, so I created the simplified version as Boolean logic, and added dabs at the top of each, pointing to the other. StuRat 17:11, 19 June 2006 (UTC)

Yes this possible solution occurred to me as well so I did the same thing and avoided even the temptation of putting a link to the new article in the existing article's "See also" section. Perhaps this way the new article will not be found and deleted before it has gained a few edits from other users who can help fight those who are unsympathetic with the needs of the layman and sometimes experts alike The real scare is that the person standing guard over the article I am concerned about has a false concept of the subject matter. Perhaps it is just as well that a new article be created to give everyone an opportunity to know the truth about the topic. ...IMHO (Talk) 19:43, 19 June 2006 (UTC)

←dragging discussion back a few indents←

Please, please, please don't just create your own fork of an article and try to hide it away somewhere. For one thing, it's very inefficient. Editors may contribute to one branch or the other, allowing both versions to be incomplete. For another, it's frustrating to our readers—they've only got a 50/50 shot of hitting the 'right' article. Finally, it's an ultimately futile effort. Eventually someone will notice the duplication and merge the two articles anyway.

There are several strategies for dealing with an article that you believe is overly technical.

• Add the {{technical}} template to the article. This flags the article as needing some added detail and description for accessibility, and adds the article to the Category:Wikipedia articles that are too technical category.
• Open a discussion on the article's talk page, and invite participation from the article's regular editor(s).
• If an article contains many technical subtopics, it may be appropriate to rewrite it in summary style. (Create a main article with short, accessible descriptions of each subtopic, and link appropriately to technical subarticles.)
• Seek comment from other editors using a request for comment. We can't help to resolve your dispute if you don't even tell us what article you're talking about.
• Finally – and most importantly – assume good faith on the part of your fellow editors. Accusing other editors of censorship, or of deliberately concealing information on behalf of some mysterious guild, tends to taint the working relationship a bit. Communication through text alone can be difficult and ambiguous. Other editors might interpret your attempts to make the article more accessible as sloppy or imprecise and be unaware of their own article ownership issues. They might feel attacked by your implications that they are censoring material or trying to hide information.

So do we at least get a hint about what article(s) you're talking about? We can't help you fix things if you won't tell us what the problem is. :D TenOfAllTrades(talk) 00:09, 20 June 2006 (UTC)

See Talk:Half-life starting June 12 and the recently created Half-life computation which has been sent to AFD Wikipedia:Articles for deletion/Half-life computation. Just a hint :-) Vsmith 02:50, 20 June 2006 (UTC)

First patented form of life...

Hi! The following question is a product of my 'momentary inattentiveness' in class(please don't avoid answering for punishing me).

What is the first 'patented form of life'? I'm quite sure, I heard the name of a scientist- Ananda Mohan Chakrabarty, in this connection(though I doubt its authenticity). How far Super Bug is related to this? Thanks,--Pupunwiki 07:51, 19 June 2006 (UTC)

hi! The first "patented form of life" was invented by the scientist CHAKRABARTY which are nothing but the OIL EATING BACTERIA.... Oil Eating Bacteria are chiefly used to clear oil spills in the process of BIOREMEDIATION In the year 1980 Chakrabarty discovered a bacteria[SUPERBUG] that could digest crude oil. SUPER BUG is said to be a strain of bacteria that is resistant to all antibiotics. It is also said to be a strain that is accidentally imported into florida from the Middle East then spread to California where it is a very serious pest feeding on almost all vegetable crops and poinsettias eg;- Bemisia tabaci, poinsettia strain some oil eating bacteria are also resistant to antibiotics...in this way super bugs are related to oil eating bacteria The oil eating bacteria Pseudomonas species is one such example for a super bug[resistant to antibiotics] --hima 10:27, 19 June 2006 (UTC)

   Thanks a lot, Hima, for clearing my doubts.
                                   --Pupunwiki 10:41, 19 June 2006 (UTC)

Well, the Diamond v. Chakrabarty resulted in the first patent for genetically modified life. But the Plant Patent Act of 1930 allows for the patenting of asexually produced cultivars, which are also "life", technically speaking. --Fastfission 13:47, 19 June 2006 (UTC)

Ridiculous Information from Wikipedia.

well, i was surfing the "war portal" on wikipedia recently. One of the articles had this link : "http://uncyclopedia.org/wiki/Palestine", under its "external links" section. And i was shocked to visit the link and the contents. And i think that site itself is open for editing, but the content still is shocking. And they have not even deleted it. Can someone help?

Uncyclopedia is in no way affiliated with Wikipedia, the site looks similar beacause they use the same software (and because they are a conscious parody site of Wikipedia). We have no influence on the content of articles on uncyclopedia, if you think their Palestine article is crossing the line of good taste, it's best to take your concerns there. Now, whether or not an external link to an uncyclopedia article is appropriate for a Wikipedia article is another matter...where did you find the link? -- Ferkelparade π 10:04, 19 June 2006 (UTC)

Thank god they don't have a reference desk. Yet. Where is this link? Wikipedia articles shouldn't link to Unencyclopedia (unless they're discussing a topic such as parody). --Shantavira 12:22, 19 June 2006 (UTC)

I read somewhere (maybe in the uncyclopedia) that it was purchased by Wikimedia. Since you can't edit articles who writes them? ...IMHO (Talk) 13:59, 19 June 2006 (UTC)

Uncyclopedia uses MediaWiki software, like Wikipedia. They are not "owned" by the same people. You can edit articles there, just like here - anyone can. What the above poster meant is that the editors here are not responsible for content there, as the majority of users do not overlap between the two sites. -Goldom ‽‽‽ ⁂ 14:32, 19 June 2006 (UTC)

It's a great outlet when you feel like posting nonsense, though! (As long as you keep it funny.) Melchoir 19:27, 19 June 2006 (UTC)

Well you can edit some things but not the majority of things in line with the idea of a contra-wiki. If you could edit everyting then it might actually serve the role of a parody where Wikipedia users could vent steam but as is its more like a spoof than a parody. ...IMHO (Talk) 19:33, 19 June 2006 (UTC)

Wavefunction, quantum mechanics, electrons etc

Quote from wavefunction -

"The complex square of the wavefunction, $|\psi |^{2}\,$, is interpreted as the probability density associated with the particle's position"

I was thinking in terms of an electron though I imagine the specific case is unimportant - my question is - Is there any reasoning or justification behind this relationship, (it seems to be a theorectical assumption used in a model) - and additionally, who originally came up with this idea and are they still alive and sufficiently sentient to be asked how/why they came up with this relationship?HappyVR 14:19, 19 June 2006 (UTC)

(disclaimer: not a physicist) Could you maybe clarify the question? Are you asking why is the complex square not simply a part of the wavefunction so that it evaluates directly to a probability? If so, this is far from a perfect answer, but it is one perspective: consider variance and standard deviation from statistics. Mathematically, variance is the simpler value, in a sense, but its units aren't the same as the original data, they are the square of those units, so the standard deviation is often used, which is simply the square root of the variance, and thus in the same units as the data. Now I'm not saying that's the real answer to your question, I'm just saying sometimes the mathematically easy quantity and the intuitively simple quantity are not the same. A better answer might be that photons/electrons/etc act like complex numbers in a sense (i.e. they follow the same rules when looked at in the right light) and it works out that once you have the complex "amplitude" for an event worked out you can square it and find the actual probability for that event. But perhaps I've only restated your question and added nothing... 128.197.81.181 18:56, 19 June 2006 (UTC)

Well - I'll try to clarify(using electrons) - within the theory, the wavefunction is a property of (an electron), physical properties can be calculated using functions operating on the wavefunction. (A bit like we could have a function describing my velocity at a given time and you could use that function to calculate how far I've gone etc). In this case the probabilty density (thats how likely it is for an electron to be found in a given region - a bit like gas density) is calculated using the complex square of the wave function - thus if the wavefunction is complex eg a+ib the propability density is (a+ib)(a-ib). I was wondering why this function - what reason - why not (for instance) the magnitude of the complex number, or indeed any other function? Whats the reason or reasoning behind it?HappyVR 09:14, 20 June 2006 (UTC)

As Probability amplitude says, this interpretation is due to Max Born who is long dead; he eventually got a Nobel for it though. Melchoir 19:24, 19 June 2006 (UTC)

Thanks for that 'melchoir', god bless Max Born.HappyVR 08:35, 20 June 2006 (UTC)

I wouldn't say it is a "theoretical assumption." It is experimentally verified. (Cj67 22:18, 19 June 2006 (UTC))

?

I have one answer now (Max Born developed this), however maybe a physicist could explain (maybe they have read Borns papers) why this relationship was chosen - is it just for simplicity - I can't see any reason why this relationship has to be right (eg units) - as possible alternatives I could suggest (using a+ib to represent a complex number) the magnitdue sqrt (a^2+b^2) or the square of the magnitude (aa+bb) as two of many possibilities as alternatives to the complex square (aa-bb) being the right answer. Can anyone explain any reason to believe that the complex square should be used as a measure of the probability density.HappyVR 08:35, 20 June 2006 (UTC)

Wavefunctions are a mathematical construction. They provide a convenient mechanism for describing the relationships which ultimately give rise to quantum mechanical observables, but they need not have any tangible meaning themselves and are never directly measured. In fact, you don't need wavefunctions to describe quantum mechanics. Matrix mechanics and mathematical formulation of quantum mechanics describe a number of alternative mathematical formulations that give rise to the same observables and hence must be equally valid descriptions of quantum mechanics. However, for many practical applications, wavefunctions are the easiest approach. In this sense, asking why should $|\psi |^{2}=|a+bi|^{2}=(a+bi)*(a-bi)=a*a+b*b$ (note, not aa-bb, as you suggest) be a probability density isn't really a sensible question. If it wasn't a probability density then it wouldn't be useful and we would be using some other formalism. However, asking what it means that this relationship holds for the intrepretation of quantum mechanics is an interesting question. In the simplistic way of thinking about things, it means that every particle describable by quantum mechanics can be equated to a wave that has not only an amplitude but also an orientation in space (e.g. a direction in the complex plane) and that determining the interactions between waves depends on considering these oreintations, but ultimately after considering any interactions it is the magnitude, the resulting a*a+b*b, that gives rise to the observable states. Dragons flight 09:13, 20 June 2006 (UTC)

oops - yes bit of a bodge up by me with the 'complex square' - however what I was asking was basically what about sqrt(aa+bb) - (in a simple sense eg addition of vectors this seems to make more sense.HappyVR 10:35, 20 June 2006 (UTC)

Or to put it much simpler - is there someway of showing that using (for instance) |sqrt(aa+bb)| as probability density is wrong?HappyVR

I think Bohm's Quantum Theory has something along these lines. - mako 08:04, 24 June 2006 (UTC)

Appropriate Waste Disposal

I have an old computer that I failed to fix. I've salvaged some components but I don't know if the motherboard works properly. It used to run on a 112 W PSU and has no AGP slots (just three PCI and some weird stubby slot). Should I just chuck the mobo and processor in the electrical waste at the tip? Should I keep the processor or PSU? What should I do with the case? Can't it be melted and used in something? There aren't enough provisions for people who want to be environmentally friendly... --Username132 (talk) 14:27, 19 June 2006 (UTC)

You can reuse the case. As for the rest, have you considered an art project? HighInBC 14:32, 19 June 2006 (UTC)

You are correct that computer parts may contain nasty stuff that you don't want ending up in landfill. The best bet is to contant your local recycling company and ask if they have a place to take it. (If your city picks up recycling, ask them, or if not, just another local company). Places like Office Depot often take in things like used-up rechargable batteries for recycling, but I doubt they'd have room to take whole MBs. -Goldom ‽‽‽ ⁂ 14:36, 19 June 2006 (UTC)

The plastic case is probably just that plastic plus some filler - maybe you could put that in any plastic recycling bin you can find. The processor is mostly inert - might contain some gold though but not much - the case will be ceramic or a resin. As far as I know its the glass fibre and the resins gluing it together and the lead used in soldering on the motherboard that are supposed to contain the nasties - no idea what you are supposed to do with this though - burning it is the way to release the chemicals enviromentalist don't like. The PSU contains sufficient scrap metal to be worth at least 50p to a scrap metal merchant - that's most of what I can say to help. (Art project is good idea - maybe you could use the processor as a coaster for small tots of rum)HappyVR 14:38, 19 June 2006 (UTC)

I'm pretty sure you could find a homeless guy that could find some way to use your junk.  freshofftheufoΓΛĿЌ  00:27, 20 June 2006 (UTC)

Why wait for a homeless person? I bet one of your friends would like a hunk of junk. I sort of would, but I'd like it to be in slightly better condition. --M1ss1ontomars2k4 ^{(T | C | @)} 04:55, 20 June 2006 (UTC)

Can medium format (120) film be developed by my local pharmacy?

Is it likely that the neighborhood drugstore would be equipped to develop 120 film? Javguerre 15:28, 19 June 2006 (UTC)

No. It is likely that your local drugstore sends all film to a processing service. It is probably easiest if you just call or visit the drugstore to ask; however you might be better served by searching for a nearby camera store (not a chain like Ritz or its siblings) and asking them for advice. --LarryMac 16:11, 19 June 2006 (UTC)

Right.......and you think getting stuff to an external service and back would allow a 1 hour turnaround? that would be some pretty impressive logistics. Plugwash 01:00, 20 June 2006 (UTC)

Where did anybody ask for 1 hour turnaround? I should have added that many stores do now have the self-contained machines that allow processing of 35MM C-41 process film on premises, but 120 is a whole different animal. --LarryMac 01:03, 20 June 2006 (UTC)

The Moon

From what points on the Earth does the moon apear largest? Thanks, Lucy Hallam

The Moon would be closest to an Earth-bound observer on Mount Everest, but that's only a 9 km difference versus a sea-level observer. By comparison, the Moon's orbit causes it to vary in distance from the Earth by 40,000 km. So actual size from earth doesn't appreciably vary no matter where you are.

However, there is a well-known Moon illusion where the Moon appears largest near the horizon, though it's simply a trick of the brain's interpretation of the image, not the actual size of the Moon itself. — Lomn | Talk 16:05, 19 June 2006 (UTC)

To be pedantic, you'd be better going up Chimborazo (volcano) than Mount Everest - it's peak is two kilmetres further from the centre of the earth than Everest's. Dmn € Դմն 21:35, 19 June 2006 (UTC)

To add to that, you should wait until perigee occurs near Chimborazo. You could be waiting for a very long time. --M1ss1ontomars2k4 ^{(T | C | @)} 04:52, 20 June 2006 (UTC)

Oh yeah. Back to the moon illusion. Due to geometry, shouldn't the moon's actual angular diameter be greatest at the zenith rather than the horizon? --M1ss1ontomars2k4 ^{(T | C | @)} 04:54, 20 June 2006 (UTC)

Yes. Moon illusion says "The true angular diameter of the Moon is about 1.5% smaller when it is near the horizon than when it is high in the sky, because it is further away by up to one Earth radius." -- Wikicheng 05:58, 20 June 2006 (UTC)

Thanks for answering that for me, much appreciated! Lucy

Fish question

What is the name of this fish? It lives deep in the ocean where there is no light. It has an extendor over its eyes that has a bulbuous attachment that glows. It was used in Disney's movie Nemo.

Maybe today you are in luck since this came up on another talk page I was reading - is it Black seadevil - it sounds v. similar. -- HappyVR 17:12, 19 June 2006 (UTC)

and Anglerfish -- HappyVR 17:13, 19 June 2006 (UTC)

It was the angler fish. — The Mac Davis] ⌇☢ ญƛ.

How much did Apollo 11 cost?

Good afternoon,

Does anyone know how much the first manned mission to land on the moon, Apollo 11, cost?

Thankyou,

Neil

Neil, is your family name Armstrong?

http://www.seds.org/spaceviews/9607/articles.html

TOTAL COST PER APOLLO MISSION:
-----------------------------
              Year   ($M)   (94$M)
Apollo 7      1968   $145    $575
Apollo 8      1968   $310  $1,230
Apollo 9      1969   $340  $1,303
Apollo 10     1969   $350  $1,341
Apollo 11     1969   $355  $1,360
Apollo 12     1970   $375  $1,389
Apollo 13     1970   $375  $1,389
Apollo 14     1971   $400  $1,421
Apollo 15     1971   $445  $1,581
Apollo 16     1972   $445  $1,519
Apollo 17     1972   $450  $1,536
---------------------------------
                   $3,990 $14,644

Have a nice afternoon. -- Toytoy 17:37, 19 June 2006 (UTC)

Thank you very much for your help; no my surname isn't Armstrong I'm afraid!

Thanks,

Neil

I didn't know Space Shuttles are THAT EXPENSIVE!

• http://www.space.com/news/shuttle_cost_050211.html

The data show that over the entire lifetime of the the space shuttle program the cost has been $145 billion, and about $112 billion since the program became operational.

Furthermore, the average cost per flight has been about $1.3 billion over the life of the program and about $750 million over its most recent five years of operations.

Now I think sending people to the moon is cheap. -- Toytoy 01:06, 20 June 2006 (UTC)

Not to get OT, but take into consideration the expanded capability of the STS, in crew capacity, flight duration, and payload. Not to say that $1.3B to gas up a ship and send it around the earth seems cheap, but...

I seem to recall a long discussion of costs at Space Shuttle. There's a lot of ways to define costs -

• Average Cost ("How much did the total program spend; then divide by number of missions...")
• Incremental Cost ("How much extra money does it cost to send one more launch, after the program infrastructure exists")
• Opportunity Cost ("How much could we have earned if we spent money elsewhere...")

... etc. There's no easy way to assign an exact dollar value to spaceflight. Nimur 17:29, 22 June 2006 (UTC)

Edibility of Cucumis melo leaves

Many cucurbits have edible leaves, but I have not been able to satisfy myself about Cucumis melo. I was surprised at how little information I could find for such a well-studied plant. BioNatural claims that the Pedi and the Sukuma people eat the leaves as a "potherb and relish", but the mention is off-hand and undetailed, and the company sells herbal extracts, so they may have a profit motive in giving this information. An agricultural researcher in Uganda lists the leaf among the plant's edible parts, but again no detail is given. Cucumis melo is not on Leaf for Life's very long list of plant species that have reportedly been eaten by people. Plants for a future reports that "the sprouting seed produces a toxic substance in its embryo", but not what the toxic substance is, where in the plant it is distributed, nor how long it persists as the plant grows.

I have added Cucumis melo to the list of plants with edible leaves, but have not eaten the leaves of the melon vines in my garden. Any further information would be appreciated. Thank you. Leafeater 17:53, 19 June 2006 (UTC)

This is a tough one. All I have to contribute is that Francois Couplan's very comprehensive The Encyclopedia of Edible Plants of North America does not mention the leaf as one of the edible parts of Cucumis melo, and he generally doesn't miss much. — Pekinensis 20:42, 23 June 2006 (UTC)

EMP nullification

What is the name of the device that nullifies the effect of an electromagnetic pulse on electronic devices? It resembles a cage made of wire. I tried a number of searches under different topics and come up empty. It's driving me crazy. —The preceding unsigned comment was added by 72.54.24.94 (talk • contribs) 19:39, 19 June 2006 UTC.

I'll put you out of your misery. See Faraday cage. --GraemeL ^(talk) 18:43, 19 June 2006 (UTC)

Thanks much. Now I can sleep at night.

JPG image problem

I have a group of jpg images which were scanned into the computer under Windows 98 using an HP Scanjet IIcx flatbed scanner. The images seem to be okay except that their widths have been compressed to about 1/3 of the left side of the page with the remainder of the page being solid black. I have never seen this before. Does anyone know what caused this and more importantly how to restore the width of the image without loss of information? Thanks. ...IMHO (Talk) 19:04, 19 June 2006 (UTC)

I guess one question that has to be asked is what did you do with them? Were they copied to a diskette or CD and were they fine when you first scanned them? I've have some problems with scanners before where no matter how many times I scan the same image, it always scans half the image wrong, and I usually assume it to be a scanner problem. If you've used storage media on the images though it might be a different problem, and there are jpeg rebuilders that may be able to fix them. Oh, and for the record, the blank area of the image is usually called the "canvas".  freshofftheufoΓΛĿЌ  00:20, 20 June 2006 (UTC)

Right the programs I have to view and edit call the whole area the canvas but I can't find the one at the moment that actually allows the image on the canvas to be streched by default rather than moved across the canvas. This is the one I had planned to use to restore the images but I am curious as to the cause. The images were fine after scanning and were only transferred from a FAT32 drive to a NTFS drive over a local Ethernet and have been there ever since. ...IMHO (Talk) 08:58, 20 June 2006 (UTC)

Ah, I see what you're getting at now. Any program like Photoshop lets you fiddle with the canvas and size settings, but as you know that's not going to leave you with the same detail as the original 1:1 images. It's not likely that the full quality image is still preserved in the file unless they've been somehow vectorized. Sorry, I can't think of why they would suddenly be compressed like that, since they obviously haven't been simply corrupted.  freshofftheufoΓΛĿЌ  10:21, 20 June 2006 (UTC)

By looking in the subdirectory (I was only looking at the results of a search for jpg files)the reason for the problem may now be revealed although I still do not understand what caused the problems. The image name ends with ....tif.jpg so it looks like they were tif images that got saved as jpg images but that still does not indicate how they were distorted in this manner. After removing the jpg extension the thumbnail image does not change and there is no effect on the edit views of the image as if the extension has been ignored and file type determined by some other means. Anyway I suspect some kind of accidental conversion due to file name change and now possibly even a virus. ...IMHO (Talk) 15:22, 20 June 2006 (UTC)

Orbit/gravity/weightlessness

I have a question relating to gravity/orbits, etc. Do you know who I can direct it to?

I understand that objects/people in orbit around the earth only appear weightless due to the fact that they are in freefall, and since the spacecraft and everything/everyone aboard are all falling at the same rate of speed around the earth (in orbit), they appear to be weightless.

My question is this:

When the astronauts travelled to the moon, they also experienced weightlessness. Since they left earth orbit on the journey to the moon, and were not in freefall, why were they weightless en route?

Jake Whalen

You should probably check out our article on weightlessness, particularly the discussion on pressure gradients. As a layman, though, here's my attempt:

Weightless freefall isn't dependent on "falling" per se but rather on you and your reference frame (that is, the spacecraft) not resisting gravitational forces, whether or not those forces will eventually cause you to collide with the relevant astronomical body. When you consider "falling" as instead being "coasting without support", weightlessness between the Earth and Moon makes a good bit more sense (to me, at least).

Also, it's a good idea not to post your phone number on the internet. — Lomn | Talk 20:02, 19 June 2006 (UTC)

Please note that weightlessness is experienced only when the spacecraft engines are shut-off (free-fall). Any time the engines are on, they exert a force on the craft and its content, and the reaction, e.g., the force exerted by the astronaut on his seat, is the equivalent of a residual weight. --Michel M Verstraete 00:04, 20 June 2006 (UTC)

Adding to Michel's answer: When the engines are turned off, even if the spacecraft is travelling away from earth, it is still 'free fall' because the only force acting on it is the gravity. So you can say that you will experience weightlessness the moment the engines are turned off, whether the spacecraft is moving away or orbiting earth -- Wikicheng 06:21, 20 June 2006 (UTC)

When you throw a ball it is in freefall from the instant it leaves your hand, even though for half of its trajectory it is "falling" upwards. Tiny astronauts inside the ball would experience "weightlessness" - right up until the point when the ball hits the ground and they are squashed by the deceleration. The Vomit Comet does the same thing, only on a bigger scale (and without the hard landing). Gandalf61 10:36, 20 June 2006 (UTC)

The original poster asked a very good question, and it is fundamental to understand it. Everyone's answer was very well written so I can't add much, but one thing : when I was a child they explained me : you are far away from earth, gravity becomes weak. Well that is simply untrue, in the International Space Station (or Mir) gravity was 9.5 m/s^2 , compared to 9.81 m/s^2 here on earth, I doubt a human would really feel that difference. The correct answer is simple : you experience weightlessness when you and your ship have exactly the same forces that work on them. Evilbu 11:07, 20 June 2006 (UTC)

Just to clarify - it is true that far from the earth the force of gravity due to the earth does become weak; it obeys an inverse square law. Around the distance of the moon, acceleration due to the earth's gravity is less than 0.01 m/s^2. When the astronauts left orbit, they did experience some acceleration due to the ship's rockets, but it was probably pretty small, and once they got far enough out, Earth's gravity became negligible. They were never completely "weightless", but nearly so. --Bmk 17:36, 20 June 2006 (UTC)

Symptoms of long-term oxygen deprivation

What are some possible symptoms of shallow breathing, or mild long-term oxygen deprivation? For instance, someone contracts sleep apnea in conjunction with asthma and allergies, causing generalized shallow breathing and low oxygen intake.

Look under "Symptoms" in the article Sleep apnea. Googling for the term also gives results. --Seejyb 01:39, 20 June 2006 (UTC)

You are actually asking about five sometimes associated, but distinct and independently diagnosable, conditions. Chronic effects, as opposed to acute effects, vary by severity from minimal to marked. At their worst, these conditions can cause some fairly serious effects over time, depending on age and co-morbidities.

1. asthma: This is usually episodic rather than continual. It usually does not cause hypoxia except in extreme exacerbations. Although it can coincidentally occur in someone with sleep apnea, it is a completely independent condition.
2. respiratory allergies: The most common of these are simply a stuffy, runny nose, not affecting oxygen level. The most severe kind of respiratory allergy (as distinct from much rarer hypersensitivity reactions) is typically allergen-triggered asthma.
3. chronic hypoventilation: This can occur from a variety of conditions ranging from genetic defects of breathing drive to congenital brain syndromes to COPD to severe obesity, but not usually from asthma. It typically causes fatigue. In a severe form it can cause chronic hypoxia, and long-term strain on heart leading to cor pulmonale and even death.
4. sleep apnea: This is most commonly due to upper airway obstruction due to obesity but can have other causes as well. It can cause transient hypoxia during sleep. It can cause daytime fatigue, headache, difficulty concentrating and remembering. There is mounting evidence that obstructive sleep apnea can contribute to the development of insulin resistance and type 2 diabetes.
5. chronic hypoxia: Chronic hypoxia has many causes ranging from COPD to chronic restrictive lung disease to chronic airway obstruction to cystic fibrosis to cyanotic congenital heart disease. Chronic hypoxia can cause a variety of long-term problems ranging from poor growth in children to fatigue and neurocognitive impairment in adults. In severe cases it can lead to cardiac hypertrophy and congestive heart failure. alteripse 02:17, 20 June 2006 (UTC)

Cigarettes, anyone ? --DLL 20:52, 20 June 2006 (UTC)

Don't forget Chronic_mountain_sickness! — The Mac Davis] ⌇☢ ญƛ.

Centrifigal Force and Gravity

Since a object on the equator is spinning faster then one on the pole, shouldn't there be a difference in weight between them? Wizrdwarts (T|C|E) 21:19, 19 June 2006 (UTC)

Yep, and there is. See Gravity (Earth) and Apparent weight. moink 21:28, 19 June 2006 (UTC)

Thanks for the quick answer! And according to the timestamp on your post, you replied one minute before I even asked! Do you know how much the actual difference would be? Wizrdwarts (T|C|E) 21:37, 19 June 2006 (UTC)

According to Gravity (Earth), 0.5% (also, Moink's timestamp is 9 minutes after yours). — Lomn | Talk 22:12, 19 June 2006 (UTC)

Must've gotten less than enough sleep today. I misread the "2" as a "1". Thanks! Wizrdwarts (T|C|E) 22:46, 19 June 2006 (UTC)

Why is AC current prefered over DC?

I've read about the subject, but I have never found a conclusive answer. There must be a major reason, otherwise we would still have both systems. Which reason is that? Afonso Silva 21:20, 19 June 2006 (UTC)

DC power supplies require a power station to be built every fifty miles or so, which becomes very impractical outside large cities. As a result, AC current is used; see the War of Currents article. Andromeda321 21:34, 19 June 2006 (UTC)

Eh, what? There's no problem with transmitting DC over long distances; for long runs high-voltage direct current (HVDC) is actually more efficient than AC. (It has a number of other advantages in certain situations, as well.) AC's major advantage is that its voltage can be easily stepped up and down with a simple transformer, making it possible to transmit current over long distances.

DC transformers are much more complicated and costly than their AC counterparts, rendering them poorly-suited for ubiquitous power grid use. TenOfAllTrades(talk) 22:23, 19 June 2006 (UTC)

There is really no such thing as a "DC transformer." AC voltage can be stepped up and down with two coils of wire and an optional lump of iron (called a transformer). DC voltages are stepped up and down with relatively complex switches and switching circuits referred to as DC-DC converters or through other more involved or less efficient means (e.g., motor-generator hookups). —Bradley 22:59, 19 June 2006 (UTC)

Thanks! I was trying to find an article in Wikipedia about it. The name is strange. Afonso Silva 22:19, 19 June 2006 (UTC)

Yeah, DC transformer is a weird thing, as DC keeps the magnetic field constant. Is that it? At least, it is what I learned. The magnetic flux must change in order to induce a current. Afonso Silva 23:13, 19 June 2006 (UTC)

Correct. As stated above, to change DC voltage levels you need converters such as the flyback converter.

As also mentioned above, there are some cases where DC transmission is used over long distances, with much lower losses, one factor that helps it is the fact that AC currents only "run through" thin layer of the conductor increasing resistance, compared to DC current that flows through the whole section of the conductor. VdSV9•♫ 01:20, 20 June 2006 (UTC)

I think it also has to do with safety purposes. I personally had the "oppurtunity" to get electrocuted by AC and DC voltages, and I found that the AC voltage actually pushes your body away so you have a chance of pulling away your hand or the part that is in contact with the circuit. But try pulling your hand from a 220 V DC (thats the common voltage in India) voltage. I think the death rate would be a lot higher if we had used DC voltage. ;-) Jayant,17 Years, India • contribs 11:55, 20 June 2006 (UTC)

Whatever you prefer, it's not been the same since Bon Scott died. --Dweller 11:59, 20 June 2006 (UTC)

AC offers numerous advantages over DC such as:

• Voltages can easily and cheaply (compared to DC) be stepped up or down using transformers for diferent transmission and distribution needs
• Using 3-phase supply allows different voltage levels to be obtained (phase-phase, phase-ground) from the same set of transmission lines
• Using 3-phase supply, loads on each phase can be balanced in order to reduce or eliminate the need for a conductor to provide the return path to earth. This means less "conductor per kilometer per megawatt", reducing costs. (This is offset by the phenomenon mentioned above about DC current flowing through the whole conductor whereas AC flows only through a thin surface layer). p.s. where is the wikipedia article on the skin depth effect?
• Protection systems in AC circuits are simpler i.e. cheaper because the current passes through a zero every cycle, which can help to extinguish e.g. a short-circuit arc

Disadvantages of AC include:

• Line inductance and capacitance to ground may be significant, especially over long distances, causing losses over and above normal resistive losses
• Power factor becomes one of the main considerations to system stability and power flow. In particular, attention has to be paid to active and reactive power
• It's just a lot more difficult to understand intuitively than DC. You've got all sorts of messy things such as series and shunt capacitors used for various purposes such as voltage boosting, improved power transmission etc.

In conclusion, the reason most systems are AC is because AC is cheaper. As for the electric shock comment, I simply don't think it is correct. An electric current through your body (AC or DC) causes your muscles to contract involuntarily. When someone touches an exposed electric circuit with their hand, muscle contraction prevents them from letting go, which is why when working on an electrical system, workers will (obviously after making sure everything is earthed!) often touch the device/conductor with the BACK of their hand to test for dangerous induced voltages (muscle contraction would then cause their hand to spasm AWAY from the metal). Zunaid 12:29, 20 June 2006 (UTC)

I think your second point on the advantages of AC – different voltages – isn't valid, as that can be done with DC as well. – b_jonas 11:01, 23 June 2006 (UTC)

Skin effect — The Mac Davis] ⌇☢ ญƛ. 01:38, 21 June 2006 (UTC)

Zunaid gave a great complete answer on the subject. But actually, as for the electric shock, it's much worse in DC, just think of a continuous 220V shock as compared to an intermitent shock. For one thing, the power dissipated by one's body will decrease to 70,7% of the DC, value, not to mention a the reactance of the human body that increases impedance.

This is not the reason "why AC is preferred over DC", I'm just clarifying this electric shock issue. VdSV9•♫ 15:47, 20 June 2006 (UTC)

That's not true. X volts of AC dissipates exactly the same power as X volts of DC in a given resistance, by definition, because AC voltages in this context are specified in RMS. Furthermore, the peak value of X volts AC is 1.41 X volts, so you would get a 41% worse shock, intermittently, from X volts AC than from X volts DC. The current due to capacitive reactance is negligible, only a few microamps (240 V * 2π * 50 Hz * 100 pF). Inductive reactance would make the current smaller. --Heron 21:22, 20 June 2006 (UTC)

Hmmm... right, it slipped my mind. Still, from all I know, the intermitent nature of AC makes the shock less damaging. And resistance and reactance are variable from person to person anyway. -- VdSV9•♫ 18:04, 21 June 2006 (UTC)

allaboutcircuits.com mentions particular hazards of both AC and DC. In summary:

• Tetanus (muscle spasm): DC worse, because you can't let go
• Ventricular fibrillation: AC worse, because it interferes with pacemaker
• Burns: no difference, if exposure time and voltage are equal (for reason given above)

There's no clear winner, which is probably why the dispute won't die. --Heron 20:57, 21 June 2006 (UTC)

June 20

Currency

Is the serial number of US currency machine readable yet? ...IMHO (Talk) 03:35, 20 June 2006 (UTC)

Is there any reason to suspect that the serial numbers are not readable by optical character recognition? I think the answer is obvious.

Should be. I saw a bit on the History Channel tonight noting the Fed having automated systems to detect superbills mixed in with legit $100 bills. — Lomn | Talk 04:49, 20 June 2006 (UTC)

Actually I am thinking more in terms of a device anyone might carry in their pocket similar to a battery powered credit card reader. ...IMHO (Talk) 08:00, 20 June 2006 (UTC)

Well, the technology certainly exists. You'd basically be doing OCR on a specific location with a roll-through scanner, and that can be done. I don't know that anybody has actually created a product, though. — Lomn | Talk 17:22, 20 June 2006 (UTC)

I don't believe such a machine would be effective in detecting forged notes. There are simple (and cheap) devices that help in that, the most common example being this ultraviolet light thing which shows small coloured strands in the note (I don't know if that applies to US currency). Compared to the other security features like this, the hologram, the metallic stripe in which you can read the minute text and the sign that fits perfectly if you hold it towards light, the watermark, etc, I believe the serial number wouldn't be too difficult to forge. Also, as new banknotes get printed all the time, to decide if the note is valid, the data in device would have to be updated frequently or have a continuous link to some central server. (Also, if you wanted a machine-readable serial number, it would probably better to use some kind of bar code.) – b_jonas 10:55, 23 June 2006 (UTC)

Stupid question

In what way is it justifiable to allow stupid people to vote, hold positions of power, etc.? By this I mean logically, as it's obvious that nearly every country's constitution gives them this right, and it is in every way illegal to exclude them of this right.  freshofftheufoΓΛĿЌ  04:15, 20 June 2006 (UTC)

Um... who decides who's "stupid"? —Keenan Pepper 04:30, 20 June 2006 (UTC)

Well that wasn't the question. In fact, I deliberately avoided that question.  freshofftheufoΓΛĿЌ  04:36, 20 June 2006 (UTC)

Assuming that "stupid" means they are not able to hold a position of power in a responsible manner, I don't believe they would be voted into that position. Appointed, perhaps. As for voting, I don't see why "stupid" people shouldn't be allowed to vote, unless they do not understand what a vote is or what the voting process means. --M1ss1ontomars2k4 ^{(T | C | @)} 04:48, 20 June 2006 (UTC)

Of course, "who is stupid" is the core question, avoided or not. Find an objective unambiguous means of defining "stupid" and you've then got a position to argue from (analagous to how many US states deny the right to vote to convicted criminals). Otherwise you've just got a regime masquerading as democracy. — Lomn | Talk 04:52, 20 June 2006 (UTC)

Intelligence is hardly the only criterion that makes somebody suitable for a leadership position. To take a simple example, the senior staff at Long Term Capital Management were extremely smart people. Didn't stop them losing an enormous pile of money through overconfidence in their own abilities. However, I think I'd expect my elected representatives to have a certain level of intelligence and intellectual curiosity. --Robert Merkel 05:09, 20 June 2006 (UTC)

People are not stupid; they are loyal to their politicians.

People are not gullible; they are ...

In a model two-party democracy, both parties offer capable and wise candidates. Even a moron can vote.

In the real world screwball democracy, ...

Anyway, democracy abhores disfranchising voters. Some countries allow criminals to be disfranchised. Some others are even afraid to do so. Making mistakes now is not the end of the world. There will be future generations to pay for our mistakes. This is democracy. -- Toytoy 07:19, 20 June 2006 (UTC)

Stupid people are idiots. The word idiot is derived from the greek idiotes meaning a private individual who doesn't participate in politics or public life. Given that in the UK almost half the people don't bother to vote, with similar figures in most other democracies, it is the case that stupid people don't vote (we can tell they're stupid because they don't vote). If they're not going to vote anyway it isn't really necessary (& could be counter productive) to actually legally prevent them from voting. AllanHainey 08:09, 20 June 2006 (UTC)

Many smart people do not vote anyway. Why you ask? They know that elected officials are the go-betweens. Go-betweens are the people who represent the bureaucracy to the public and the public to the bureaucracy. For this reason the stupidity or lack thereof among elected officials is virtually nullified. ...IMHO (Talk) 08:08, 20 June 2006 (UTC)

The other reason why smart people don't vote is that they can not decide which stupid one to vote for. - Wikicheng 08:33, 20 June 2006 (UTC)

Depending on who you think are the stupid people, they are possibly the most likely type of people to vote.

Let me try something else: If I set the definition of stupid as a "person who has a low ability to make correct, logical decisions independently in a variety of situations" does that work better? I'm curious about M1ss1ontom's opinion. And as for Lomn's comment, I believe most certainly that it is possible to argue without a position on "stupid", just like you can argue about the existance of God whether you believe or not. You just have to allow some assumptions.  freshofftheufoΓΛĿЌ  09:58, 20 June 2006 (UTC)

It's not whether you believe or not -- I believe some people are stupid -- but whether you can create any meaningful basis for discussion. To use your example, most discussions as to whether God exists understand that they're discussing an omnipotent supernatural being, not just some lame superhero like Aquaman. A useful discussion about God is impractical if one of the parties is instead arguing the existence of his dog.

Therefore, without some standard, all you're asking the ref desk is whether or not we think it's a good idea for you to dictate who votes, and the core point is that when an arbitrary standard is sued to select voters, the actual power lies only with the people who set the standard. — Lomn | Talk 14:23, 20 June 2006 (UTC)

As an additional note, "stupid" is a particularly vague term. It's possible to debate political vagaries (say, is it right to tax the rich more than the poor) so long as at least an objective comparison is understood -- a rich person makes more money than a poor one, in tax terms -- even if the precise boundaries aren't defined (how much income constitutes "rich"). However, what's the measuring stick for "stupid" vs "smart"? — Lomn | Talk 14:27, 20 June 2006 (UTC)

Well, I don't know about stupid people, but if you want to exclude particular groups from democracy based on character traits, how about selfish, or lazy, or greedy, or racist, or not policitally correct? Would you rather your representative was stupid or greedy? Stupid or racist? Where does it stop? The particular problem with excluding people from democracy in large numbers is that they are likely to be upset; if you exclude enough you have the potential for unrest or revolution. The general problem in all these cases is making a definition, because in practical terms you couldn't propose a real action or estimate effects until you make a definition of the term. Notinasnaid 12:53, 20 June 2006 (UTC)

The thing is, I never suggested that they shouldn't be allowed. I was actually asking why they should be.  freshofftheufoΓΛĿЌ  16:53, 20 June 2006 (UTC)

Do you see how that's a loaded question suggesting that they shouldn't be, though? Anyway, to try to answer the original question: stupid people should be able to vote because no one has presented a coherent objective case as to why they shouldn't, and modern liberal democracies generally agree that elective rights are restricted primarily by age and citizenship. — Lomn | Talk 17:24, 20 June 2006 (UTC)

Women decided to prove they were no more idiots in the beginning of the last century. Before, only rich and educated people did vote - as in Athens.

Each time politicians allowed some groups to vote, thet did so because they hoped they would gain more votes than the other party. What if pets and IA machines were allowed to help us choosing ? --DLL 20:49, 20 June 2006 (UTC)

I suspect you're talking about the USA. Women have had the vote continuously since 1893 in New Zealand and 1894 in South Australia. JackofOz 09:25, 22 June 2006 (UTC)

In case you're interested, the kind of government you propose, where intelligence forms a primary criterion for voting/governence, is called a geniocracy. GeeJo ^(t)⁄_(c) • 23:00, 20 June 2006 (UTC)

At elections, everyone hears from the television how many people have voted and more importantly, how many had the right to vote. Thus, if stupid people weren't allowed to vote, it would get out very soon that there are so many stupid pepole in the country or state. I believe this would have a bad impact on people's mood, especially if they started to compare figures from all the regions. People would be discriminated just because they come from a region where fewer people can vote. – b_jonas 10:48, 23 June 2006 (UTC)

=Do you suffer from short-term memory loss? - I don't remember

Hi, I've looked at Short term memory, working memory & amnesia but I can't find what I'm looking for. Does anyone know if there is a condition which renders someone unable, or makes it harder to, remember regular or irregularly recurring events once they've happened once. For example something that would make it harder for someone to remember to renew a monthly bus season ticket after she had bought the ticket the first time; or which made it harder to remember to pay regular council tax bills?

I realise that there may not be a name for this other than "forgetfullness" or "disorganised" but if there is a specific condition or conditions which could have this effect could you please let me know.

Thanks AllanHainey 07:55, 20 June 2006 (UTC)

I guess we would have to know the rest of the person's story. Many different things, from anterograde amnesia to dementia/delirium to depression can all cause the symptoms you describe. The key is to know what else is going on and what the rest of the brain is capable of doing! InvictaHOG 10:45, 20 June 2006 (UTC)

I hope this doesn't come over as flippant, but it just sounds like a perfectly normal pattern. At least in my experience. The first time you have to pay that bill, it will pray on my mind until it is done. After that, it's impossible for me to hold in my head that it needs doing over and over. What you need is not a better memory, but better organisation. It's hard, and I'm bad at it, but a key thing is not to have lots of places to check: just one master list of things to do. Then you only have to remember to check the list once a week, and have the discipline to both check and act. Notinasnaid 10:53, 20 June 2006 (UTC)

What was the question ? --DLL 20:50, 20 June 2006 (UTC)

Medicine

What does the "C" stand for in vitamin C?

Apparently nothing. I thought it might be citrus but it appears to have been used because it's the letter after B (or possibly because it simply wasn't taken yet).  freshofftheufoΓΛĿЌ  10:05, 20 June 2006 (UTC)

• Like many things in science, I think this was just convenient naming. A, B, C, D.... - Mgm|^(talk) 12:50, 20 June 2006 (UTC)

What about Vitamin K? Why was it named so? (Assuming that vitamin K actually exists, I am not too good in biology) Jayant,17 Years, India • contribs 13:09, 20 June 2006 (UTC)

K = koagulation. The MadSci Network has answered this. –Mysid^(t) 13:12, 20 June 2006 (UTC)

It is named because it was derived from and added features to B. C++ added classes, templates, etc, by Bjerne Stroupguard. (Object oriented, etc). There's no "D" derived from "C", though, to whoever said thait.

He was talking about vitamins not Object oriented programming languages.;-) Jayant,17 Years, India • contribs 20:23, 20 June 2006 (UTC)

Maybe some emoticons are just to be supposed in most part of these pages ;-). --DLL 20:42, 20 June 2006 (UTC)

I wonder why nobody pointed to vitamin. This has some info -- Wikicheng 09:35, 21 June 2006 (UTC)

electricity in sea water

Hi, Its simple but i have this in mind for long time.. In rainy season,in road side some transformer may get burst and the wires get fallen in rain water,so the people who are all walking in settled rain water get shocked. My question is like the same thing, if some transformer or current giving thing get fallen in sea water,what about the flow of current in the water?Is the whole water get current?If people swim in sea hat happende to them?

• They get electrocuted if they touch conducting material or are swimming closely to the source of the shock. But the farther away they are the less likely they are to get a shock because the available current would either spread or go through to the ground. The first would spread it over such a large area it's no longer dangerous, the second would mean it's gone in seconds. - Mgm|^(talk) 12:48, 20 June 2006 (UTC)
• It's an issue even when an electric power transmission cable is torn and falls to the ground. Ground is also a conductor, so the current spreads from the cable in all directions. If you happen to be near you are advised not to make long steps (so that the potential between your feet is not too high) or even to jump on one foot. Conscious 04:38, 21 June 2006 (UTC)

Another quantum mechanics question

Using the wavefunction derived on Hydrogen-like atom can anyone point me to a page that shows or describes how to calculate (using a quantum mechanical method) the energy of (or energy difference between) quantum states. I was thinking for simplicity of taking the energy when the quantum number (n) tends to infinity as being 'zero' as this seems to approximate totally separate electron and proton. Does this energy correspond to using a semi classical method of using the wavefunction to give propabilty density and using that probabilty density function combined with coloumb potential integrated over all space to give the 'average energy' of a wave-like electron?HappyVR 11:46, 20 June 2006 (UTC)

The purely quantum method is to solve the Schrodinger equation HΨ = E·Ψ, where the resulting eigenvalues E are the energy levels of each orbital. For some reason, we have the solutions for Ψ but not for E in the hydrogen-like atom article. Instead, the solution for E is in hydrogen atom. Hope that helps, anyway. (And yes, as you can see, as n goes to infinity, you get to zero potential energy.) To be honest, I haven't tried integrating the probability-weighted potential...I suspect that it ought to give you the right total potential energy, and I'd be concerned if it didn't. TenOfAllTrades(talk) 15:15, 20 June 2006 (UTC)

If you know the wave function, energy is just HΨ/Ψ, indeed (and it's constant if you have the right wavefunction). For your second question, quasiclassical approximation is applicable when n >> 1. (Either I don't know the correct English term or we should have an article on this.) Conscious 04:34, 21 June 2006 (UTC)

Cutting animals in half?

Could someone be kind enough to satisfy my curiosity and post a list of animals which can be cut into two (or more) pieces and survive, with each piece growing into a separate creature? Cheers. --Kurt Shaped Box 11:54, 20 June 2006 (UTC)

Are you planning to cut animals in half? That said, the planarian would work nicely. --Zemyla^t 12:39, 20 June 2006 (UTC)

• The story that earthworms can regenerate in such a way they form two worms afterwards is an urban legend as this link and various others show. Given the fact such animals would require duplicate organs, I actually doubt any animals can do this. The living part of some animals can regenerate limbs and/or tails, but the cut-off part will never grow into a full animal itself. - Mgm|^(talk) 12:44, 20 June 2006 (UTC)

Colonial animals such as sponges and corals. Gdr 12:53, 20 June 2006 (UTC)

... and a species of starfish called Linckia laevigata can grow a new individual from a single severed arm. Gandalf61 12:56, 20 June 2006 (UTC)

(edit conflict) What about starfish? I heard that if you chop off one of their arms, it'll becoming a new starfish. But it could just be an urban myth. Jayant,17 Years, India • contribs 13:02, 20 June 2006 (UTC)

It is true. The starfish has an extraordinary ability to regererate. But for a chopped-off arm to grow a complete new starfish, the arm must be of sufficient size – and, as I've heard, the arm should include at least part of the central disc, too. –Mysid^(t) 13:10, 20 June 2006 (UTC)

Then if people can give examples of animals that can regenerate, there must be a full list. --Proficient 22:01, 20 June 2006 (UTC)

how does biology affects our life?

how does biology affects our life?

Without it we wouldn't be alive. Perhaps you should read biology and come back with specific questions that you need help with. Dismas|^(talk) 13:35, 20 June 2006 (UTC)

Do your own homework, kid.  :-) -Quasipalm 16:01, 20 June 2006 (UTC)

Jumping from a height?

Is it possible for a human to fall from a height of about 1-5 stories without injury reliably? I'm getting tired of taking the stairs... --Zemyla^t 13:57, 20 June 2006 (UTC)

That's quite a range... I would think it has a lot to do with the physical condition of the person as well as what they are landing on. Concrete would be much harder than grass, sand, or gravel. I used to jump from a height of about 12-15 feet when I was a kid to escape being beat up by the bigger kids on the playground (they'd chase me to the top of a slide, I'd jump, that would give me a few seconds to get away) but I doubt I could do it very often now without straining something. Dismas|^(talk) 14:13, 20 June 2006 (UTC)

And the ground was designed to be fallen upon. Most buildings have wood or concrete floors covered with linoleum or carpeting and falling on them would be very different from falling on loose sand, rubber, or gravel. Emmett5 16:24, 20 June 2006 (UTC)

• It happened. I even heard about a parachutist that survived a fall when his chute didn't open. But don't count on it being in any way reliable when it comes to not getting injured. - Mgm|^(talk) 18:08, 20 June 2006 (UTC)

So I'd say it depends mostly on the material. The height and state of the person are also very important. I would not risk trying it though. --Proficient 22:04, 20 June 2006 (UTC)

If you use the same setup as stuntmen do, and jump into a giant airbag, then yes, you can jump from that height and survive. It is important to land back first, however, to distribute the force evenly. StuRat 00:02, 21 June 2006 (UTC)

The biggest danger in jumping from such heights is broken bones, twisted ankles, that sort of thing. One storey is definitely doable, although I wouldn't recommend it on a regular basis. Two storeys, you run a high risk of broken bones - soft, even ground helps some but not much (although, if you have to jump in an emergency, you probably will survive). Three and above, you run a high risk of death. This is all assuming that you're landing on 'ordinary' materials - a huge airbag (as StuRat said) is a very good surface to land on, even from great heights, but you need to land correctly. You can dive into water from 10-12m without much danger, but make sure you land feet first and ensure the water is deep enough! — QuantumEleven 09:09, 21 June 2006 (UTC)

Falling in an elevator

Can we infer then, from StuRats reply, that the best thing to do if being trapped in an elevator which starts falling from the fifth floor, would be to lie down on your back? --62.16.189.71 06:02, 21 June 2006 (UTC)

Not sure about that... but it does suggestion I've wondered about for a while. Say you're trapped in something like an elevator and you can tell exactly when it will hit the ground. A split second before it hits, you jump up in the air. Assuming that the elevator survives intact, are you more likely to be uninjured than if you'd just stood in the elevator or braced yourself for impact? Grutness...wha? 06:19, 21 June 2006 (UTC)

No - this is a myth (see the book Worst Cast Scenario). The upward speed you can create by jumping isn't anywhere near enough to compensate for the speed of the falling elevator. Your best bet to survive in a falling elevator is to try and distribute the force as much as possible by lying on your back or on your stomach, trying not to damage your vital organs. Even then, it's dicey. — QuantumEleven 09:30, 21 June 2006 (UTC)

Guys, you have forgotten weightlessness in a falling elevator. The moment the elevator starts falling, you'll lose your footing and you will be floating in the air, falling along with the elevator. You will not be able to anything (turn / jump up etc), except to wait till the elevator hits the bottom. This is, not considering the shock and panic at that moment -- Wikicheng 10:16, 21 June 2006 (UTC)

I dont understand. You wouldnt be going that fast, so why would you die?

This is one of many of the questions discussed in the (frankly hilarious) book, "Why Girls Can't Throw: And Other Questions You Always Wanted Answered" by Mitchell Symons (ISBN: 0060835184 for the hardback) which is an excellent "toilet-reading" book. Symons comes to similar conclusions to those above, but argues (reasonably convincingly) that your best chances of survival lie in having travelled in a lift where you have fellow passengers who are (preferably) fat. --Dweller 10:21, 21 June 2006 (UTC)

If we assume the elevator isn't quite in free fall due to resistance from the walls of the elevator shaft, then you would have a choice of what to do. While lying on your back is best to reduce the risk of any injury in a mild impact, that's not the case in the elevator. Since you are certain to suffer major injuries, the goal is to just stay alive. I would suggest that standing upright, with the knees slightly bent, would be best. This would allow the legs to fold and then fracture on impact, hopefully protecting the vital organs in the abdomen and head from fatal forces. StuRat 12:32, 21 June 2006 (UTC)

Although, if you were nearly weightless, you could attempt to gather your body into a tight ball spinning at high-speed, and when you landed you would roll around distributing the shock of the fall to all parts of your body. It'd be funny to watch on the CCD after it all ended too.  freshofftheufoΓΛĿЌ  16:24, 21 June 2006 (UTC)

Actually, your best chance is to pinch yourself and wake up, because I don't think an elevator has ever fallen, at least not in the last 100 years. If you look down an elevator shaft, you'll see they have massive cables up the wazoo - way overkill, thankfully. (correct me if I'm wrong about elevators never crashing - i didn't actually research that)--Bmk 21:25, 21 June 2006 (UTC)

Elevators still fall, but due to emergency brakes, nowadays they are usually stopped (relatively) gently before they hit the bottom. But not always. A Google News search on elevator fall turned up this article from today. And here are two recent articles about elevator falls where the emergency brakes stopped the car before it hit bottom. Chuck 21:48, 21 June 2006 (UTC)

Wikicheng, because of friction between the elevator and the tracks you would still have...god some physicist is going to stab me in the face for putting it this way..."some gravity". --mboverload@ 02:38, 22 June 2006 (UTC)

Hairyness and evolution

Male and female primates are both very hairy. What is the evolutionary reason for female humans being so hairless? What is the evolutionary reason for both sexes sprouting armpit hair, but not knee hair? Hairy Dweller 14:10, 20 June 2006 (UTC)

Here is something to consider:

• The bare truth - Why are humans nearly hairless? And why do some wish to become more so?

For many decades, the most popular explanation of hairlessness was that humans lost their hair to keep cool. Too much hair made humans—very active apes—hot, like elephants. Elephants evolved huge floppy ears to radiate heat back into their surroundings. But when hominids moved out of the forests and into the savannah, the same task could be carried out by the entire body, thanks to hominids' upright posture (which exposed less skin to the sun) and their lack of hair.

Mark Pagel, at the University of Reading, and Sir Walter Bodmer, at the John Radcliffe Hospital in Oxford, have a new idea. They believe that parasites are the key to human hairlessness. Humans, they say, lost their hair in order to reduce the burden of parasites such as fleas and ticks, some of which would have transmitted disease. Early humans probably lived close together in hunter-gatherer groups, in which the rate of parasite transmission was high. Hairless skin was easier to keep clean. Cultural adaptations, such as the use of fire, shelter and clothing, allowed humans to become furless.

-Quasipalm 16:04, 20 June 2006 (UTC)

Really interesting, but to be harsh, it actually doesn't answer either of the questions I posed. a) why are women less hairy and b) why do we have armpit hair? --16:08, 20 June 2006 (UTC)

The fact that women are less hairy is probably a secondary sex characteristic, and armpit and pubic hair are believed to have remained for reasons of friction and pheromones.  freshofftheufoΓΛĿЌ  16:49, 20 June 2006 (UTC)

Nice. So women are hairless to appear different. Difficult to imagine an evolutionary mechanism for that though. Hairy 'pits reduce friction? Again, I think it would be difficult to demonstrate a survival advantage there. But as a non-scientist, my understanding of evolution is probably as childish as my sense of humour. --Dweller 17:49, 20 June 2006 (UTC)

For the former, many species have different appearances for genders. For the latter, reducing chafing and irritation would seem a clear (albeit minor) survival advantage. — Lomn | Talk 18:12, 20 June 2006 (UTC)

The Naked Ape: A Zoologist's Study of the Human Animal (ISBN 0385334303) by Desmond Morris. Read this, it's fun and sometimes more fun. --DLL 20:39, 20 June 2006 (UTC)

Just my 2 cents. Human Females have a layer of fat just under the skin which males normally do not have. This provides a measure of insulation against the cold which means less body hair is needed to keep warm.

Men have fat under their skin, too, although perhaps less than women. When I cut my arm on a piece of glass, I saw the little yellow fat globules myself. StuRat 23:58, 20 June 2006 (UTC)

Very cool answers. Thank you. Still unconvinced, but enjoying the banter. Also, thanks for proving that scientists can answer questions in plain English. Just wish your cousins on the Mathematics page were able to do so. (Mind you, I brought it on myself) --Dweller 21:19, 20 June 2006 (UTC)

Secondary sex characteristics don't only emerge as ways to differenciate the sexes. One of the only logical explanations why human breasts are so much larger than those of other mammals is that they evolved as an attractive trait. This makes sense because a healthier female (with better access to food) would more likely be able to sustain large breasts and it would be extremely easy for a male to recognize that. You could as well theorize that it is easier for hairless females to show off their health than patchy hairy ones, though that doesn't explain why other animals don't evolve in the same way. It's probably a much more complex combination of factors.  freshofftheufoΓΛĿЌ  05:22, 21 June 2006 (UTC)

• The "science" is breast augmentation, hair removal, et cetera.Patchouli 05:36, 23 June 2006 (UTC)

Not sure how much this is really backed up by science, but supposedly humans lost hair after the domestication of fire. With an external means of keeping warm at night, hair wasn't necessary and, since hair hosted parasites, became a liability. Hair remained where sweat glands doubled as scent glands and the head, which had more stringent requirements for protection from cold or sun. However, that doesn't explain beards or male pattern baldness... Peter Grey 05:55, 21 June 2006 (UTC)

I have heard something similar, stating that hair disappeared after HS started wearing clothing, probably around the same time that they started using fire, and possibly for the same reasons. Facial hair could be a secondary sex characteristic too, or some similar visual feature.  freshofftheufoΓΛĿЌ  16:19, 21 June 2006 (UTC)

Women do have as much hair as men, it's just much finer. The coarseness of body hair has to do with the timing of introduction and the dosage of male hormones. Read up on Polycystic ovary syndrome, anabolic steroids, Hirsutism, and Sex hormones. A theory for the existence of underarm and groin hair is to trap body scent indicators, for the purpose of reproduction and scent recognition of relatives. Try reading up on Underarm hair and Pubic hair.--Anchoress 20:45, 21 June 2006 (UTC)

• You can see that there are people who have no bodily hair except pubic hair. They have less hair than any sort of human - man or woman. Warning: Explicit Site.Patchouli 05:01, 23 June 2006 (UTC)

Circumcision

I just read the circumcision article, but couldn't find any information on how the "string" that runs on the back of the penis is "dealt with". Isn't the "string" some kind of "tube" for urin and semen? How does one avoid not cutting it off when doing a circumcision? Jack Daw 14:46, 20 June 2006 (UTC)

I think you're talking about the frenulum; it's a band of tissue that runs along the bottom of the foreskin...? It is not involved in the passage of urine or semen; all of that happens in the urethra. the frenulum is frequently trimmed or removed during circumcision without ill effect—it only contains some small blood vessels which heal rapidly. TenOfAllTrades(talk) 15:18, 20 June 2006 (UTC)

It's harmless to cut off. --Proficient 22:05, 20 June 2006 (UTC)

Though I wouldn't recommend trying this out for yourself... GeeJo ^(t)⁄_(c) • 23:10, 20 June 2006 (UTC)

I wonder whether the word "harmless" is appropriate for this procedure. I think that it is more correct to say that the dissection of the frenulum is a normal part of cicumcision, which typically does not produce immediate or long-term physical harm.Tuckerekcut 23:44, 20 June 2006 (UTC)

Nota bene: There is a small but noisy contingent of people who have very strong opinions about circumcision, either pro or con. Be careful about circumcision info you find on the web. A lot of it is provided by such people, so stick to very reputable sources. --George 04:16, 21 June 2006 (UTC)

Interesting comment, George. Are you saying that someone with a very strong opinion one way or the other, about this or any other subject, is ipso facto out of contention as "very reputable"? Does your own post above count as a "strong opinion", and does that make your proferred advice not very reputable? JackofOz 09:12, 22 June 2006 (UTC)

Texas Instruments subfamily abbreviations

Hi all. I'm trying to figure out what some Texas Instruments IC subfamily abbreviations stand for. For example, I know that LS stands for "Low power Schottky". I want to know what other abbreviations stand for, such as NE, SA and SE (specifically for the 555 timer). Thanks! ~MDD4696 16:19, 20 June 2006 (UTC)

Actually, I believe the NE, SA and SE abbreviations belong to Fairchild Semiconductor... but I still have no idea what they mean! Perhaps they're just random.... ~MDD4696 18:50, 20 June 2006 (UTC)

Signetics, according to 555 timer IC. Data sheets like this STM one say that those three prefixes refer to different temperature grades. I can't find out why those particular letters were chosen, though. --Heron 20:13, 20 June 2006 (UTC)

Ethanol

Do you have any information on how to make ethanol from paper

Thank you Richard--203.109.165.249 22:44, 20 June 2006 (UTC)

The most efficient route would be to add cellulase, typically from symbiotic bacteria from ruminants, which'd break the cellulose to glucose. From there, add yeast in anaerobic conditions to produce ethanol GeeJo ^(t)⁄_(c) • 23:18, 20 June 2006 (UTC)

Microsoft Outlook Problem

When I type the word products in an Outlook e-mail message, pr appears on the first line and oducts jumps to the second line. How can I fix this?Patchouli 23:26, 20 June 2006 (UTC)

It could be an autocorrect problem. Try clicking the 'undo' button right after. If that fixes it (shows products correctly), someone's played a joke on you and added an autororrect to Word, which you can correct in word.--Anchoress 23:29, 20 June 2006 (UTC)

• I sent the e-mail. Now when I look at the e-mail in the Sent Items folder, the word products is not disconnected and appears whole.

Use AutoCorrect when Word isn't the e-mail editor check box is currently selected. Should I deselect it?Patchouli 23:55, 20 June 2006 (UTC)

Well if the email looks fine now, it probably wasn't an autocorrect problem. Sometimes, either because of refresh problems, font size/paragraph alignment etc, words will appear to break across lines. Of paramount importance is whether or not it ever was apparant that the text was broken across lines in your unsent message? Did you check? Because if it was, you'll have to wait until it happens again and investigate further. If it wasn't, then it's just a failure of WYSIWYG and can be ignored. As for the Autocorrect, don't change anything unless or until you know for sure it's a problem.--Anchoress 12:48, 21 June 2006 (UTC)

• Thanks.Patchouli 23:53, 21 June 2006 (UTC)

June 21

Bismuth Tellurium Transistors used in water heating/cooling

I just recently heard about a device using bismuth telluride transistors that has the potential to boil/freeze water in seconds from the power of two flashlight batteries. I read this randomly in an old version of the CRC handbook of Chemistry and Physics. I, personally, really enjoy building things, and I would like to add this to my wanted collection, but I do not know where to begin, let alone have the schematic for such a device. I want to ask how should I build this device, and where can I gather the proper information regarding the potential power outputs and details of this machine?

Sounds like Thermoelectric cooling. DMacks 01:00, 21 June 2006 (UTC)

I don't believe there is sufficient energy in two flashlight batteries to boil or freeze any significant amount of water, even if we could release all of it instantaneously. Perhaps if you could use mains power... but you'd probably blow a fuse. Thermoelectric cooling is neat, but it isn't magic. ~MDD4696 03:39, 21 June 2006 (UTC)

---

Ha! Something I know a lot about! I entered this into the Junior Science and Humanities Symposium through the US DOD. This is called a Peltier junction, and I believe that page redirects into thermoelectricity (last time I was there). They are really fun! I blew mine out with more than five amperes (oh crap). What I had done was run so much current through, I either melted the bismuth-tellurium (I don't know it's melting point) or I had melted the sodder leads which flowed into the Peltier-Seebeck junction. As a note, "Peltier junctions" are used in cooling applications, and "Seebeck junctions" are used in heating. Although the heat is just "moved" using the thermoelectric effect, usually Peltier junctions are used, because there is always an opulence of heat. Peltier junctions are usually used in microprocessor cooling applications when hackers modify their processors to run at dangerously high speeds. As for the heating and freezing, in my experience with commecrially-made ones, you need at least two-three amperes before water vapor starts to directly freeze out of the air.

Construction/Parts: Ceramic plates are on each side of the sandwitch of bismuth-tellurium to create a smooth flat surface area, a freakin lot of the bismuth-tellurium alloy curved sandwitches are bent around between the ceramic (read the links already above to get this).

Building is tough! Unless you've been doing this kind of thing for decades you won't be able to. You have to have at least 20 P-N-P junctions right next to each other for it to work, and a pretty high density (I think mine was something like ~200/in². All I remember is that you'll need a fume hood and some great smelting skills and lots of bismuth and tellurium. I tried to

Buying is your best bet. You can buy a great one off of eBay for reeeally cheap. I think mine was between forty and sixty dollars. The junction density is prime and the bismuth-tellurium structures are industrial-made. Google it correctly and there are some awesome mods people do with Peltier junctions. My favorites involve the portable mini-, single-can- beer cooler.

— The Mac Davis] ⌇☢ ญƛ. 04:30, 21 June 2006 (UTC)

---

Science

What kind of plastic do they use in plastic surgery?-Bee(y)^Ti 01:17, 21 June 2006 (UTC)

Sometimes when plastics is hurt; you send it to a hospital. If a man hits your car's plastic bumper; you must send it to a hospital to perform immediate surgery. -- Toytoy 01:33, 21 June 2006 (UTC)

Plastic surgery has nothing to do with plastic materials. The word plastic comes from the Greek πλασσειν, meaning "form", "mould", or "shape". Originally only flexible materials were called plastic, but now the word is commonly applied to all synthetic polymers, even rigid ones. Plastic surgery is surgery in which the flesh is molded into a different shape. —Keenan Pepper 01:46, 21 June 2006 (UTC)

Usually squished or pulled into a different shape. — The Mac Davis] ⌇☢ ญƛ.

It would depend on the plastic individual's health insurance. I'm sure they'd do their best to match the original plastic. Peter Grey 06:09, 21 June 2006 (UTC)

Silicone. (--Shantavira 06:44, 21 June 2006 (UTC))

When a family member injured her hand slicing an avocado, we were told by the plastic surgeon that operated on her that the most common reason why people in London require plastic surgery is because of accidents to the hand while cutting fruit and veg. Avocados are particularly troublesome because of the combination of the softness of the fruit and the hardness and slipperiness of the stone. "Avocado cuts" are the number 1 cause for "middle class" families, apparently. Plastic surgery using silicone/plastic on people's chests (or wherever on their bodies) is apparently off-the-scale less common than routine repairs to skin injuries etc. --Dweller 10:13, 21 June 2006 (UTC)

Plastics are used in surgical implants, both temporary and permanent, but this is, as noted above, unrelated to the use of the term "plastic surgery". Plastics may be used in plastic surgery, as in other surgical fields. Other materials, like titanium, may also be used in any form of surgery. StuRat 13:18, 21 June 2006 (UTC)

Color and black body radiation

What is "color" molecularly? Are there any certain rules that say certian combination of particles create certain colors? How about the black body case? How does black body radiation work in this case molecularly?

• colors depend on the frequency and color of the futons emitted by the black body--—The preceding comment was added by Beeyti (talk • contribs) . 01:58, 21 June 2006 (UTC)

I'm sorry, but what on earth do futons have to do with it? Colour is determined by the frequency of EM radiation emitted by the source. On the receiver's end, colour can be determined by the cells reacting to the radiation. See trichromatic vision for details. GeeJo ^(t)⁄_(c) • 02:31, 21 June 2006 (UTC)

Yes, there are rules that determine the colors of substances given their chemical compositions, but they are very complex. See crystal field theory which explains why blood is red and grass is green. Black body radiation has nothing to do with color at room temperature, because black bodies at room temperature are, well, black. —Keenan Pepper 02:41, 21 June 2006 (UTC)

However black body radiation does change the frequency and color of emissions from a body. — The Mac Davis] ⌇☢ ญƛ.

At room temperature? —Keenan Pepper 05:02, 21 June 2006 (UTC)

Hehe... No... --10:17, 21 June 2006 (UTC)

Yeah, sorry. I obviously left that part out (unconciously), becuase you had just said that. Add a "at very high temperatures" to that. :) — The Mac Davis] ⌇☢ ญƛ. 22:17, 21 June 2006 (UTC)

Many of the relevant articles really need some additional explanation for non-scientists, but to sketch it out, you have electrons that are flying around very quickly around the atoms make up matter. These electrons are flying around so quickly that it's often better to describe their location as being within a cloud where any given electron is more or less likely to be at any one time.

The shape and size of these clouds varies according to the molecule(s) involved. Said another way, when you have two or more atoms in a molecular bond, their electron clouds combine and interact in ever more complex ways.

A side-effect of these electron clouds is that they will absorb or repel different wavelengths of light; basically different colors of light. And so the combination of the color of the incoming light, combined with the electrons in these clouds leads to what we perceive as the color of an object.

I've tried to make it understandable and avoid jargon, but certain terms really are needed for a discussion like this. Also, this is really not my field, so hopefully someone better versed in quantum chemistry will chime in.--Tachikoma 16:20, 22 June 2006 (UTC)

Cockroaches

I've heard that after we spray a cockroach with a pesticide, the cockroache transfers its DNA that is resistant to that kind of pesticide to its offspring, am I right? If I am, how do they do it, i mean, shouldn't they be dead by then? How do they change their DNA?

The only way that resistance can be propagated in a population of cockroaches is by the following sequence of events:

1. The presence in a population of cockroaches of various degrees of heritable vulnerability and resistance to pesticide, followed by
2. the killing off of the susceptible ones by spraying of the pesticide, followed by
3. successful reproduction of the surviving resistant cockroaches, followed by
4. now a much higher proportion of resistant cockroaches in the local population.

You have been hearing nonsense from the ignorant. Animals and plants do not consciously select the genes or change the genes they pass to their offspring. As long as you have a population with a variety of genes, and the presence of pressures that reduce the reproductive success of some of the gene types, the genetic make-up of the population will change. This is how evolution works. Why are there so many people out there who think they understand mutation and evolution and spread this kind of nonsense when they wouldn't dream of claiming knowledge of cell biology? alteripse 03:36, 21 June 2006 (UTC)

Thanks a lot!

Diluting sulfuric acid

How can you work out how hot a solution will become when diluting sulfuric acid? Eg. 98% -> 20%, how much energy will be given off?

Thanks very much

210.246.0.84 04:32, 21 June 2006 (UTC)

• Any type of chemical process involves the transfer of energy. Any chemical has a certain amount of energy stored in its molecule. Dissolving sulfuric acid would release the energy. All you need to figure out is how much energy you need to heat the resulting solution 1 degree, then see how many degrees you can heat it with the energy you got. - Mgm|^(talk) 07:46, 21 June 2006 (UTC)
• There is no simple way to calculate this, it is one of the technical points which you learn doing practical chemistry. When I demonstrate the dilution of sulfuric acid to my students, I prepare a solution which is roughly 50%: this easily gets to excess of 80 °C. I then get the students to carefully touch the flask, which demonstrates why conc. sulfuric acid is so dangerous... Physchim62 (talk) 08:21, 21 June 2006 (UTC)

Train Vs Fly

Someone told me this riddle once but never left me with the answer. Perhaps someone here can help.

A fly is flying along a railway track at, say, 5 kph. He is hit by a locomotive travelling at 100 kph in the opposite direction. The fly quickly decelerates from 5 kph and, considering he is now squashed to the train, travels at 100 kph in the opposite direction to what he was initialy flying.

Re: the deceleration- he would have decelerated very (very) quickly from 5 kph in order to travel at 100 kph in the opp direction (5,4,3,2,1,0,1,2,3,4...100 all of which would have happened in the blink of an eye).

But for the briefest moment his speed would have been zero (the moment between travelling forward and traveliing along with the train). Now if he is not moving, and he is attached to the front of the train, surely this means the train isn't moving (if only for the briefest of moments)

Of course I know a fly can't stop a train so what is the explanation?

Sorry if I made this more complicated than it should be!

A variation on Zeno's Paradox. Speed (velocity, technically) is distance per unit time. If you're considering, not the briefest moment, but zero elapsed time, then you would be "stopped" only in the sense of considering a zero displacement, no different from if the fly wasn't there at all. Unless you wanted someone to explain motion on the scale of Planck time (that would really be cool!) Peter Grey 06:06, 21 June 2006 (UTC)

This riddle has a corollary. What was the last thing to go through the fly's head?--Shantavira 06:48, 21 June 2006 (UTC)

His ass. Johntex\^talk 08:28, 21 June 2006 (UTC)

I don't think it's really a variation of Zeno's paradox; even over a finite length of time the fly will have a velocity of close to zero. The key is that implicit in the questioner's reasoning is that the the fly (and train) are point-like or rigid structures. They're not, of course. One could track the center of mass of the fly and it certainly would slow, come to a stop, then speed up in the other direction, and yes, if you neglect the effects of wind/air, this will occur after the fly has come in contact with the train. However (not to be gruesome), after the head has come in contact with the train, it will begin to be squashed towards the body. At the instant the center of mass of the fly is stationary, the back part of the fly is still moving towards the train, while the train is continuing forward squashing the head of the fly. If the fly were a point-like particle, it would bounce off the front of the change, instantaneously changing velocities. It would never have a velocity of zero; the derivative of its position at that instant would be undefined. Of course, all of this assumes classical mechanics; in reality (well, in quantum mechanics), position, velocity, and time become hazy if you probe them too deeply. — Knowledge Seeker দ 08:22, 21 June 2006 (UTC)

A fly can't stop a train, but a train can stop a fly - where's the paradox? Physchim62 (talk) 08:24, 21 June 2006 (UTC)

Perhaps harder to explain, but surely the same paradox; what about a cricket ball being hit by a cricket bat. Does the cricket ball (shall we say, does the centre of gravity of the cricket ball) ever have a velocity of zero? Is it only during the brief instant where both bat and ball are compressing at their mutual surface, and compressing at a rate that compensates for the combined velocity (over 100 mph?) Notinasnaid 09:48, 21 June 2006 (UTC)

We're making a mountain out of a molehill here, the answer is pretty simple: when a fly hits a train, there will be a moment when the fly is at rest. Since at that moment, the fly is in contact with the train (ie is being squashed by it), the surface it's in contact with will also be at rest. If the train were a completely solid, undeformable object, that would mean the fly would stop the train (even if only for an instant). What happens in reality is the material the fly impacts (eg the windshield) deforms on impact, and it will be momentarily at rest. Of course, it will spring back almost immediately, and oscillate a few times, which is where the sound you hear on impact comes from: the windshield vibrating.

So, the fly doesn't stop the train, but it does stop the windshield. The same goes for the cricket ball - if we treat both objects as being deformable (which they are), then the contact surface between the two will be momentarily at rest on impact. However, almost immediately, both the ball and bat will be compressed by a certain amount, and since the bat is much more massive than the ball, the bulk of its mass will continue moving forward without stopping. — QuantumEleven 12:09, 21 June 2006 (UTC)

QuantumEleven makes excellent points except for one minor (insignificant?) detail! The bat is not much more massive than the ball. The reason it continues forward is because an external force is being supplied to the bat. The bat and ball are of similar masses such that the momentum is matched (similar to Impedance matching in electric circuits - maximum power is transferred only if the masses are closely matched. Otherwise, great explanations. Nimur 18:30, 23 June 2006 (UTC)

Er, the fly never stops anything, not even necessarily the first layer of atoms on the windshield's surface. The velocity of the fly-as-point-particle corresponds to the average velocity of the fly, which is 0 when the fly's butt and head are moving in opposite directions (i.e., the fly is squishing). At no time is it necessary for the windshield (which is only touching the head, not the center of gravity) to be stationary. You could argue that the head itself must have 0 velocity at some point; then we refine it to "the windshield is only touching the front of the fly's head". Then you say that even that must stop at some point, and eventually we're arguing about individual atoms on the surface of the fly. As those are too small to be "in contact" with anything, the argument that any part of the train must have the same speed as them breaks down. (Also, remember that all velocities are relative; all of this is in a frame where the fly and train were moving in opposite directions before impact and the train's velocity wasn't negligible.) --Tardis 00:40, 24 June 2006 (UTC)

I've seen photos taken with high-speed lens/film that show different kinds of balls deforming. Tennis balls, being so squashy, are naturally a great subject for this type of shot. A cricket ball feels extremely hard, but its leather surface and (frankly rather odd) innards will nonetheless compress. --Dweller 12:14, 21 June 2006 (UTC)

• None of the tennis ball pix I could find on Google were much good, but here's a nice one of a rubber ball deforming [5]

Also, on the impact, the windshield of the train will undergo some deformity (it will bend back a bit) and then (after some oscillations) come to its normal position. There will be the instant when the train is moving forward but the windshield (with the fly squashed against it) is moving backward. This combination (of WS+fly) can attain zero velocity. It all becomes too messy (to calculate and also physically) because the fly gets squashed -- Wikicheng 13:43, 21 June 2006 (UTC)

Please see my above post in this same section: the windshield need not move backward except relative to the rest of the train (as it must deform to apply force to the fly), and that movement can be entirely insignificant compared to the train's velocity (which can be anything, since we can fling the fly at a train instead of ramming the fly with the train). --Tardis 00:40, 24 June 2006 (UTC)

Mobile phones radiation

Hello. Is there any article or websaite about the radiation that is generated from different types of mobile phones? If possible, I would like to see a website that contains all brands and models of mobile phones. Thank you! --Alexignatiou 06:23, 21 June 2006

[6].... u can get som information here....--hima 09:19, 21 June 2006 (UTC)

First, you might be interested in our article about mobile phone radiation and health.

Secondly, if this worries you, have you considered buying and using a handsfree kit?

Thirdly, here's such a site, using published data from the manufacturers. I found this in about 10 seconds by using Google to search for the words mobile phone radiation comparison. Try searching first, it's quicker. --Robert Merkel 09:13, 21 June 2006 (UTC)

I did search, however I didn't find what I was looking for. And it's not something that worries me, I don't use mobile phones a lot, just because I always hear stuff... Thanks, anyway --Alexignatiou 13:04, 21 June 2006 (UTC)

What is the safety factor of a handsfree kit? Instead of putting radiation near my brain, I should but it near my balls? That makes no sense. --Kainaw ^(talk) 15:52, 21 June 2006 (UTC)

Answering seriously, and to say something that has not been said without jumping into the links: Cell phones do not release the kind of radiation that you may at first think they do. They release electromagnetic radiation, but it won't give you cancer. The United States government I recall as having spent some hundreds of millions or a few billion dollars on clearning up this panic in the United States about powerlines. The scare has also existed with microwave ovens. — The Mac Davis] ⌇☢ ญƛ. 22:23, 21 June 2006 (UTC)

Aircraft Safety

I have seen destructive videos of an blade coming loose in a turbine fan of the air intake of a jet engine.Instead,Why cant they make a composite fan and then surround all its blades with a ring,so that even if one blade brakes the plane can still land safely?Guess it would be stronger and lastlonger.

A composite fan is difficult to do at present because composites are not strong enough to widthstand the forces in a compressor fan. As for the 'ring', that's already done - all jet engines have reinforcement in the cowling around their compressor and turbine blades, so that if a blade should detach when the engine is spinning (this is called a blade-off), the engine will contain the blade and prevent it from damaging the rest of the aircraft. As a matter of fact, it's a requirement for the engine to be allowed to fly, it must contain the damage should a blade detach.

This used to be a bit of a problem with propeller aircraft - without any cowling, there would be nothing stopping a detached blade from zooming away at high speed and hitting something. Nowadays, this happens very rarely, but on some propeller aircraft (eg the ATR aircraft) you can still see the reinforcement of the fuselage wall near the propeller. — QuantumEleven 09:00, 21 June 2006 (UTC)

I read a story, either in the National Geographic or New Scientist about the design and construction of the A380. It discussed this requirement somewhat. IIRC, it was quite a scary time for them (as it would be for any aircraft design team) when they tested it... Nil Einne 14:36, 21 June 2006 (UTC)

I saw a test when they where making the big airbus thing that they had to build a complte engine and then destrucivlty test this it by blowing a propller of when the engine was at full power, which is slightly expensive as the engine was said to be worth its weight in gold --Colsmeghead 21:54, 21 June 2006 (UTC)

Just a note: Those fans have a completely insane amount of kinetic energy. You'd need QUITE a ring. I remember awhile ago I saw a program about how a turboprop pretty much fucked the whole backside of a plane with shrapnel. I think it may have been a military plane...I don't remember if they died or not... --mboverload@ 02:29, 22 June 2006 (UTC)

Yup, that's why those rings are made of some very strong stuff :) If you think the fans in turbofans are bad, the blades in turboprops are much worse: they spin at about the same speed, but each blade is considerably heavier (there are fewer of them). If a turboprop blade were to detach at full speed, it would likely go straight through the fuselage and maybe even out the other side... hence the need for, to put a name on it, armour :) (note that modern propeller designs mean that there are very few blade detachs, so no need to get worried about flying on turboprops!) — QuantumEleven 06:30, 22 June 2006 (UTC)

I did not mean a stationary ring on the body of the engine cover,but a ring attached to all the ends of the blades(Something like the rim of a cycle wheel with spokes) that rotates along with the blades

Electromagnetic Question

If an inductor were charged,but its terminals were placed far apart so that it would not short when open.Would the wave become am Electro Magnetic Wave?

Also,If light were to enter a drop of water,we know it would choose the shortest path as soon as it enters the light drop(refraction).But what if the shape of the drop had changed as the light is still in between the drop?GUESS it would again choose the path of shortest distace.BUT observing this change,is it possible to predict the future shape of the drop,or is it that shape is the cause,direction is the effect?

I don't understand your first question, but as for the second... you seem to be referring to Fermat's principle. The thing is, light rays don't have any foresight or predictive power. As a ray of light travels, it bends due to changes in the local refractive index, but it doesn't know about what lies ahead. Mathematically speaking, the extremum in Fermat's principle is a local extremum, not a global extremum. Melchoir 19:23, 21 June 2006 (UTC)

Re your first question, an inductor doesn't really get charged. What happens instead is that you store energy in the magnetic field. You may be thinking of a capacitor. But anyway you seem to be describing a steady-state situation. To have a wave you need to have some kind of oscillation. The question is rather confusing; could you describe in more detail what you mean? Arbitrary username 20:22, 21 June 2006 (UTC)

Better Solar Panels

Is it possible to make the sunlight induce a charge by virtue of its EMW nature rather than just cause photonic emmision and build better solar panels?

Your question is a bit confusing - perhaps you should read photovoltaic cell.--Bmk 21:38, 21 June 2006 (UTC)

The question does not make any sense. I am unfamiliar with EMW natures. If my mind is just not being sharp, that's ok, but I suggest you stay away from that kind of "scientific" material. — The Mac Davis] ⌇☢ ญƛ. 22:25, 21 June 2006 (UTC)

The swift answer is no (or at least unlikely). The frequency of the electromagnetic waves in sunlight (where most of the energy comes from) is way beyond the potential (unbound) electron oscillation frequency in most materials. Quite simply, the electrons can't move quickly enough, and if they can, no harnessable current is produced (unlike radio wave EM induction). --Eh-Steve 08:16, 22 June 2006 (UTC)

Sunglasses

Is there a method to test the uv blocking effectiveness of sun glasses at home?

I found this at Netwon/ANL's Ask a Scientist and modified it (in [square brackets]) to fit into this situation:

A way of testing the [UV] transparency is to place the [sunglasses] between the UV light source and a piece of high quality white paper. The paper will fluoresce a bright blue if there is no [filter] present. If the bright blue disappears when you put the [sunglasses] in between, the [glasses are] absorbing the UV light.

I doubt that's a very accurate method to test the filter's effectiveness, but at least it can be done at home. –Mysid^(t) 09:37, 21 June 2006 (UTC)

As far as I know, glass absorbs UV rays (that is why Fluorescent lamps are safe, even though they have UV rays inside them). So the sunglasses made of glass is the simplest UV protection. Am I wrong on this? -- Wikicheng 13:53, 21 June 2006 (UTC)

Not all glass absorbs UV, otherwise how do you expect a Black light to work? The key in fluorescent bulbs is the white powder they coat the glass with, it causes the UV to (wait for it...) *Fluoresce* into white(ish) light. If you have a true UV source, what better test is there for a UV blocker than trying to stop the UV from hitting a surface and fluorescing? It's pretty obvious when it works.

The article Ultraviolet says Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths. It also says the range of UV wavelengths is often subdivided into UVA (380–315 nm), also called Long Wave or "blacklight"; UVB (315–280 nm), also called Medium Wave; and UVC (< 280 nm), also called Short Wave or "germicidal" . This means that ordinary glass blocks most of the UV (except the longer blacklight). The article also mentions Tungsten-halogen lamps have bulbs made of quartz, not of ordinary glass. Tungsten-halogen lamps that are not filtered by an additional layer of ordinary glass are a common, useful, and possibly dangerous, source of UVB light. But the surprise is Ordinary eyeglasses give some protection, and most plastic lenses give more protection than glass lenses -- Wikicheng 15:04, 21 June 2006 (UTC)

But where would i get the uv light source from?

Also, let's make clear that opaque and transparent aren't yes-no answers - there are degrees of opacity (e.g., blocks 95% of all UV rays... etc). As for a UV light source, you could use a Black Light (available in a lot of stores, esp. novelty stores, but maybe even stores such as a WalMart). You might also try a halogen lamp; they usually have a (removable) glass cover to block UV rays. Be careful as both the intense heat and the UV rays of a halogen lamp may be harmful if you are continuously exposed to either. Nimur 18:43, 23 June 2006 (UTC)

Osmosis in potatoes

Dear all I need to conduct an experiment on Osmosis in potatoes, and for that I need to write a scientific background and an extension. I know the scientific background of Osmosis, but as an extension, does the surface of potatoe affect Osmosis and if so, how could one carry out an experiment on such phenomenon? This is NOT a homework question but an extension task to my write-up

• Have you read Osmosis? The surface is probably the semi-permeable membrane between the water and the surface cells. - Mgm|^(talk) 11:40, 21 June 2006 (UTC)

Does surface area of the potato affect the Osmosis?

Absolutely. I would, in general, expect the osmosis rate to be proportional to the surface area, until the potato chunks are "soaked thru". If you have some substance you can submerge potatoes into, allow osmosis, and then detect the quantity absorbed by the potatoes, then you can design an experiment. Submerge a whole potato in a given quantity of the substance, then submerge a chopped up potato in the same quantity for the same length of time. I suggest peeling both potatoes first to avoid any effect of differing osmosis rates thru the peel than thru the rest of the potato. A simple, but less accurate, test would be to put the potatoes in iodine, then mash them and look at the color. The chopped up potatoes will presumably have much more color than the whole potato. The timing is critical, however; if you soak them too long both will be fully soaked with iodine, and show the same color. StuRat 12:56, 21 June 2006 (UTC)

Processor Architecture

If I'm installing Linux on a machine with two processor boards, should I look for a distribution designed for a 64-bit processor architecture? --Username132 (talk) 10:06, 21 June 2006 (UTC)

No, unless you know the processors are indeed 64-bit. Instead, look for the abbreviation SMP (symmetric multiprocessing), which refers to the use of multiple CPUs. –Mysid^(t) 11:11, 21 June 2006 (UTC)

You need a linux kernel compiled specifically for SMP machines (otherwise only one CPU will be actually used). Some linux distributions already have one, but when it doesn't, you have to compile one yourself. You may also have to do turn on a special option if the machine has more than 1 gigabyte of RAM. – b_jonas 10:22, 23 June 2006 (UTC)

I forget where I buried my threads...

I post lots of things on lots of different forums. It would be nice to be able to use one single program to track all my threads and keep me informed of replies. I sometimes forget to check up on a thread or even where I posted it. --Username132 (talk) 11:32, 21 June 2006 (UTC)

Help:Watching pages may help. --hydnjo talk 12:06, 21 June 2006 (UTC)

I'm assuming it's for the whole net, not just WP. First, consider using either your favourites or adding links to your browser toolbar (AFAIK you can do this with most). Most BBS software has a feature where it will show the most recent 50 or so posts by a user, so rather than creating a link to every single active thread on the net, you can just create a link to your author pages on BBSs you post to.--Anchoress 12:44, 21 June 2006 (UTC)

• I agree with Username132. How difficult would it be to modify the MediaWiki software to provide RSS feeds or email notification of replies to all wiki discussions? --JWSchmidt 01:58, 22 June 2006 (UTC)

I think it would be failry difficult, more trouble than it would worth. As this is a wiki, MediaWiki doesn't know about threads. People edit the text of pages, not add reply to "threads". If you want to be able to follow threads, you'll have to use a software more like a message-board.

Also, someone has mentioned watching pages. In addittion to that, the "my contributions" link can also help. – b_jonas 10:28, 23 June 2006 (UTC)

Well, MediaWiki does allow for sending email when a page on one's watchlist is edited, but imagine the amount of email that would ensue... it was turned off for performance and spamming reasons in Wikimedia wikis. Titoxd^(?!?) 05:21, 24 June 2006 (UTC)

THREE CLASIIFICATIONS OF TECHNOLOGY

What are three classifications of technology and meanings of each classification.

1. Homework questions blatantly copied directly from the book or worksheet.
2. Homework questions poorly disguised as legitimate ref desk questions.
3. Homework questions well disguised as legitimate ref desk questions.

StuRat 13:07, 21 June 2006 (UTC)

Broken, impractical and obsolete --Dweller 13:15, 21 June 2006 (UTC)

Stone age, space age, garbage ? Gandalf61 14:00, 21 June 2006 (UTC)

Too much, too little, and wrong kind?--inks^T 21:18, 21 June 2006 (UTC)

One, two and three? --ColourBurst 04:56, 22 June 2006 (UTC)

Out of date, soon to be out of date, not yet created and thus doesn't yet have the opportunity to be out of date. --Fastfission 18:17, 21 June 2006 (UTC)

That's the winner! --Dweller 11:26, 22 June 2006 (UTC)

The question absolutely needs context, because there are no actual "three classifications of technology." Just those described in the book. Is this high school level? --The Mac Davis] ⌇☢ ญƛ. 00:10, 22 June 2006 (UTC)

Cheap, good, and fast? – b_jonas 09:46, 23 June 2006 (UTC)

Lowering cholesterol levels through exercise

How is cholesterol levels lowered through exercise? What's the process? Jack Daw 13:23, 21 June 2006 (UTC)

While perhaps not completely answering your question, the cholesterol (especially the regulation section) and the hypercholesterolemia articles should help. Nil Einne 14:52, 21 June 2006 (UTC)

Yeah the latter says that exercise is one way to lower cholesterol levels, but it doesn't say how it works. Thanks though. Jack Daw 20:00, 21 June 2006 (UTC)

If I were to hazard a guess, i would say that the increased cellular turnover induced by excersize would help lower cholesterol through cell formation. Also, changes in steroid production may factor in (although, as i remember, cortisol production decreases with improved excersize habits). This segmaent, taken from the HDL article, may also shed some light on the subject:

In the stress response, serum amyloid A, which is one of the acute phase proteins and an apolipoprotein, is under the stimulation of cytokines (IL-1, IL-6) and cortisol produced in the liver and carried to the damaged tissue incorporated into HDL particles. At the inflammation site, it attracts and activates leukocytes. In chronic inflammations, its deposition in the tissues manifests itself as amyloidosis.

Sorry I can't be more specific.Tuckerekcut 21:40, 21 June 2006 (UTC)

That's specific enough, thanks! :D Jack Daw 23:18, 21 June 2006 (UTC)

Paleocollapse

I did another article! But did I finally kick my refdesk addiction? --Zeizmic 14:17, 21 June 2006 (UTC)

I've done you a favor and rephrased your comment into an acceptable question, as you seemed to have forgotten to ask one!  freshofftheufoΓΛĿЌ  15:33, 21 June 2006 (UTC)

Zeizmic, could you rephrase your question? I have no idea what you're asking.--Yanwen 18:55, 21 June 2006 (UTC)

Shortest & longest day

According to the Solstice page, the June solstice was on the 21st at 12:26 UTC. According to my local paper in NZ, tomorrow (well today now for me), June 22th is the shortest day. The solstice was at 0:26 on June 22nd here (since we're +12) so I guess this is why the shortest day is the 22nd. Am I right that the longest day in Malaysia, UTC+8 would have been June 21st since the solstice would have been at 20:26 (on the 21st)? Or is it more complex then that? N.B. I appreciate the difference is very small, especially so in a equitorial country such as Malaysia. Nil Einne 14:44, 21 June 2006 (UTC)

Wouldn't an equatorial country have two longest days each year. Philc _T^E_C^I 15:13, 21 June 2006 (UTC)

I believe you're mistaken. The summer solstice is still the summer solstice (depending on which hemisphere the country or area is in) and the winter solstice is still the winter solstice. Of course, there is no real climatical seasonal differences in an equatorial country. For example, in Malaysia, the June solstice is the summer solstice. If you happen to be on the equator, there is no longest day or shortest day I believe since there is no variation between daylength. Nil Einne 15:47, 21 June 2006 (UTC)

BTW, incase you haven't realised, I was using equatorial country in the loose sense (as it is frequently used) to mean the same thing as tropical country. Of course, even a country that is on the equator, would still have summer and winter solstices, except on the equator itself of course. Nil Einne 16:17, 21 June 2006 (UTC)

THats what I mean, on the equator itslef, the country would have two longest days, due to the leaning of the earth. Philc _T^E_C^I 16:20, 21 June 2006 (UTC)

As I discussed above, unless I'm mistaken when you're on the equator there is no longest or shortest day. Each day is the same. As you move away from the equator, south or north this is no longer true (technically). It's been a long time since I took any physics but I would assume that even a metre away from the equator, there is still technically a longest day and a shortest day even if the difference is in microseconds. The longest day is still on or about the summer solstice and the shortest day is still on or about the winter solstice.

BTW, of course a country that has a part on the equator would also have parts in both the south and northern hemisphere. Therefore it would have a longest day in the southern hemisphere which is the shortest day in the northern hemispehere and vice versa. In this sense it would have two longest days, perhaps this is what you meant. But in a specific area, it's still either the longest day or shortest day (or just the solstice on the equator). Nil Einne 16:32, 21 June 2006 (UTC)

I disagree. The day is longest at the equator when the Sun appears to go directly overhead, which happens twice a year, at the vernal and autumnal equinox. However, I don't think there is nearly as much variation in the length of a day at the equator as there is in temperate zones (and, of course, the huge variation in day lengths at the poles). StuRat 16:41, 21 June 2006 (UTC)

Exactly my point, due to the tilt of the earths axis, as the year passes the sun will be directly over head first one hemisphere then the other, crossing the equator twice. Philc _T^E_C^I 16:48, 21 June 2006 (UTC)

I've been trying to do this in my head, but I have a severe headache. So, on the equator, the solstice is the longest day (regardless of which solstice it is). The equinoxes are the shortest days (one shorter than the other), right? At what degree latitude do they change so that the equinoxesa are equal length days and one solstice is longest and one is shortest? What about that latitude right in the middle? --Kainaw ^(talk) 17:50, 21 June 2006 (UTC)

See Tropic of Cancer and Tropic of Capricorn for more information on which latitudes are the northmost and southmost of the sun's overhead travel. See Equator for that latitude right in the middle. Also, something handy for day length calculation is This navy site which will compute the sunrise/sunset times for any place on the globe. Pick a spot between the To'Cancer and To'Capricorn and see the effect on day length compared to any spot outside that.

(re-indenting for clarity) I've likewise been hurting my head with mental math, but a tropical location will still conform to the usual longest-day / shortest-day relation to the solstices. However, at the equator, the day/night cycle is precisely divided at the solstice, just as it is at the equinox. Since the length of day at the equator is a sine function with the same period as that at every other latitude, the only function that puts a 12 hour day at 0 rad and pi/2 rad is one with no magnitude; that is, the length of day at the equator doesn't vary. Sidenote: due to how the length of day is measured (any point of sun over horizon, not midpoint), the day is always longer than 12 hours. See also the graph linked from solstice at this site — Lomn | Talk 18:34, 21 June 2006 (UTC)

Thanks for that, it's as I expected. I checked out the solstice article but not really the links. I also missed length of day which is equally useful. This appears to have settle the above issue, as I expected in a tropical location it's still the normal situation. Precisely on the equator, there is no variation in daylength. As you move away, there is variation but obviously e.g. a second away would have such a small difference to be meaningless. Having lived in Malaysia (KL, 3 degrees, 8 min), I know the difference is small but is not completely insignificant, about 30 minutes between longest and shortest. Of course, you do hardly notice it compared to e.g. you do here in Auckland (let alone somewhere like London).

However I'm still a bit uncertain about my original question namely how do you work out which is the longest day from the summer solstice (or the shortest day from the winter solstice). After more thinking, I'm guessing I was wrong above but it doesn't matter in most circumstances. You can't say for sure the day of the summer solstice would be the longest day since it will depend on factors such as your timezone in comparison to your actual longitude. In most case it will be but my guess here is that is actually depends which day length period is closer to the time when the summer (or winter) solstice occured.

So for example, in Malaysia since the summer solstice occured at June 21st 2026 (local time), the longest day would have clearly been June 21st since the June 21st sunset (about 1900) is far closer to the solstice then the June 22n sunrise (about 0700).

In New Zealand (or Auckland), it's a little more complex. The winter solstice occured at June 22nd 0026 as mentioned above. The sunset time on the 21st (according to a calendar I have for 2006) was at 1712 while sunrise for 22nd is at 0734. The sunrise on 22nd is closer (7h8m) then the previous sunrise (7h14m) so the 22nd is the shortest day but if the solstice was at 0001 for example clearly it would have been different.

Of course, it's probably easier just to work it out mathematically and in any case, given we're talking about a sine graph here, the difference between day length of the longest (or shortest) day and the day just before and just after are minute (even more so when the difference in daylength is so small as in Malaysia) but it's interestingly nevertheless.

Nil Einne 08:00, 22 June 2006 (UTC)

Here is a site with sunrise and sunset data for Quito, Ecuador, which is close to the equator: [7]. The length of each day is about 12 hours and 7 minutes, with earliest sunrise and sunsets around November 3 and May 13 and latest around July 26 and Feb 12. StuRat 03:16, 24 June 2006 (UTC)

Larva

We had recently found a small spot on our dining room ceiling. It contained Alot of little (probably 1-2 millimeters long) of black worm looking things. They had been there for a few weeks. There were almost hundreds of them. I have searched and searched, but have no luck finding any pictures or anything on them. I don't know if we need to spray our house our what? and for what? I have a baby on the way and would like to find out ASAP, please please help! Thanks, <-- email removed--> 207.69.138.6 16:58, 21 June 2006 (UTC)--

Well, it's not good, whatever it is. Get an infestation control person round asap. You could be risking the integrity of the structure of your house in the long term if this gets out of control. Trollderella 22:02, 21 June 2006 (UTC)

Ehm, irony doesn't travel well over the Internet. At least, I hope this was irony. :) DirkvdM 08:05, 23 June 2006 (UTC)

Java SDK

What is a recommended Java SDK for developing Java programs? I have the JS2E Runtime Enviorment 5.0 Update 6 installed. Is there any traditional SDK I can get similar to how the VM is the one and only? --Chris 17:39, 21 June 2006 (UTC)

There are only two Java SDK's to my knowledge. There is the official one from Sun (with multiple versions from 2.x to 5.x). Then, there is the Gnu version that is commonly distributed with Fedora Linux. Of the two, the official one would be best. I suggest using a lower version for compatability (like 4.x) and a higher one for the latest features. You appear to be asking which IDE is best used for developing Java programs. That is a completely different question. --Kainaw ^(talk) 17:47, 21 June 2006 (UTC)

Okay, maybe that is what I'm asking. I got my terms confused. Any answers? what is this thing called Net Beans? I programmed in Java before using jGRASP, but I never had to install the necessary components by myself. This is why I'm asking. --Chris 19:13, 21 June 2006 (UTC)

NetBeans are a collection of objects that you can use in your programs. Sun has an IDE that makes NetBeans easy to use (the NetBeans IDE). Also, the free Eclipse IDE (from IBM if I remember correctly) allows you to easily choose NetBeans (as well as many other object repositories) for code usage. If you only want to use your objects (and the default set of Java objects), than any IDE is fine. Both NetBeans IDE and Eclipse allow you to compile and run with a single button click and both have on-the-fly popups to "help" you. I put that in quotes because I hate it when boxes pop up while I'm trying to work. --Kainaw ^(talk) 19:23, 21 June 2006 (UTC)

There are probably hundreds of SDK's, actually - there is the OFFICIAL SUN JAVA SDK [8] as well as many other corporations or open-source groups who have created their own versions of the compiler (for various reasons ranging from business/license restrictions; running on unusual/obscure hardware; removing or adding features for performance, security, or connectivity; etc etc etc). Further, there are also multiple types of java: Standard Edition, Micro Edition, and Enterprise Edition. SE is the "standard" java you probably want. EE is for large corporate networks who have intense networking, security, and reliability needs. ME is designed for deployment on small devices such as PDAs, Cell Phones and VCRs, or embedded systems. Your best bet is the one linked above. Good luck, Nimur 18:52, 23 June 2006 (UTC)

Propane....

Hi, are you ok? I hope so...

I don't know much about this, so I need your help.

I would like to know if propane lights up, does it create a expansive wave?

Could that be posible if a place's air is full of propane and it lights up?

Please... I need that info...

If you don't understand something please answer me. Thank you.

You appear to be asking if propane can explode. Yes. It can. --Kainaw ^(talk) 18:26, 21 June 2006 (UTC)

also, this may be obvious, but "there's no one here" -- I don't know who you were addressing, but the reference desk is empty. Volunteers edit answers on to the questions.

I'm have a tab open with this most of the day. -- The Mac Davis] ⌇☢ ญƛ. 00:13, 22 June 2006 (UTC)

What I find more interesting is: why does the propane flame in the bbq always make a loud 'wump' when you turn off the burners? There must be some air collapse, but I always thought this would be just a slow fade. --Zeizmic 19:33, 21 June 2006 (UTC)

Wow, that's a great question. There's so many things in life that we never think about. I think it was only a few years ago that they actually found out why coffee stains are light in the middle and have very dark edges =D --mboverload@ 02:24, 22 June 2006 (UTC)

Quite simple actually. Once the fuel supply is cut off, there is a higher Oxygen : Fuel ratio, so the fuel "bangs" rather than burns. This is why a room full of oxygen and propane will explode, not just burn (provided the O₂ is well mixed and there is enough of it) .--Eh-Steve 08:24, 22 June 2006 (UTC)

What i mean is this.... Imagine this scenario: A place like a sears store. It's air is full of propane due to an escape. So someting lights it up. I know that the flames are going to wrap everything up and everything is gonna burn. But the "explosion" if there is in this case, may produce a expansive wave enoughly strong to blow out all the windows of the store? Or the propane light up doesn't create a expansive wave?

No, it will create a shockwave given the right fuel-oxygen mixture, otherwise it will simply burn. Thats how thermobaric explosions work. --Eh-Steve 05:14, 23 June 2006 (UTC)

how phenolphthalein was invented/discovered?

how phenolphthalein was invented/discovered?

Search for Adolf von Baeyer's experiments - especially those done in the 1870s. --Kainaw ^(talk) 19:40, 21 June 2006 (UTC)

Death

Unstable radioactive isotopes subject to Beta decay which are not replenished say within a container will eventually die out in the same manner as living organisms will die out on an island which are likewise not replenished and fail to reproduce.

Is this statement true or false?

...IMHO (Talk) 20:17, 21 June 2006 (UTC)

To be more succint: probability suggests that all atoms of a radioactive isotope will eventually decay, provided they're not being replenished. However, something being true isn't a justification for "winning" an edit war, as (among other things) the relevance of the fact to the article must be considered. — Lomn | Talk 20:38, 21 June 2006 (UTC)

See latter portions of Talk:Half-life for the rationale for my "however" comment — Lomn | Talk

In that case you should have no problem answering this question rather than skirting. ...IMHO (Talk) 21:22, 21 June 2006 (UTC)

I feel that I did answer the question, I just found the analogy to living organisms cumbersome (as, apparently, did Melchior) as it seemed to be unrelated to your primary question. If I have misinterpreted, please amend my response to that of Melchior's: atoms do not decay like people.

To be blunt, though, this looks like an attempt to drag a content dispute away from the relevant talk page and/or dispute resolution mechanisms (might I suggest WP:3O?). Therefore, I tried to gently insert a suggestion along those lines. — Lomn | Talk 21:33, 21 June 2006 (UTC)

Bottom line here is revealing the truth. You need to answer "yes" or "no" to the question rather than to defer to someone else. ...IMHO (Talk) 21:53, 21 June 2006 (UTC)

Please remain civil. Melchior and I are both attempting to answer a rather vague question as best we can. As I've noted, your question, as posed, is vague enough that a "yes" or "no" isn't really sufficient. — Lomn | Talk 22:27, 21 June 2006 (UTC)

False. The fundamental principle behind the statistics of radioactive decay is that an individual atom's probability to decay is independent of its age. This is not true of the deaths of living beings! Even if the half-life of a non-reproducing human population is 50 years, within 200 years literally all of them will be dead. But for a population of radioactive isotopes with a half-life of 50 years, after 200 years 1/16 of them will have survived. Melchoir 20:59, 21 June 2006 (UTC)

Do you mind showing a table of values which with the fraction or percent of isotopes for each year over the span of the 200 years? ...IMHO (Talk) 21:17, 21 June 2006 (UTC)

Each year? I'll do it for five bucks, no less. Melchoir 21:22, 21 June 2006 (UTC)

Don't do it for me. Do it for other users. I submitted my evidence for free. Please provide the same courtesy for them. ...IMHO (Talk) 21:25, 21 June 2006 (UTC)

I get the feeling that there isn't a huge audience for a 200-row table of values whose only purpose is to verify that 2^4=16. Melchoir 21:28, 21 June 2006 (UTC)

Okay using your own criteria (above) of percentage remaining p=1/(2^(200/50)) consider this:

We want to know the percentage remaining after 200 years of any amount of anything that has a half life of 50 years.

We therefore apply the formula p=1/(2^(number of years/half-life)) or p=1/(2^(200/50)) or 1/16 or .0625 or 6.25%.

So it appears that since there is a percentage of 6.25% of the item left after 200 years that it does not matter what the item is or how much of the item there was to start off with. This is where your concept fails. For instance suppose that we start with only 10 items. How much will we have left after 200 years. That’s easy. we just multply .0625 times 10 and we get .625. Thus we have .635 items left after 200 years of the original 10 we started with. But what if the items are not divisible? What if there is not such a thing as .625 of the items we have and that any amount of the item that is less than one simply does not exist? Hummm... Since we can not divide an atom into parts by the method of Beta decay then sorry but even though we might have 6.25% of the original amount of the items left that percent is meaningless because 1.) we started with only ten items and 2.) each item is a complete and indivisible unit rather than a continuous value. If you apply half-life computation to the real world then you must take these facts into account. ...IMHO (Talk) 03:15, 22 June 2006 (UTC)

See below. Melchoir 03:50, 22 June 2006 (UTC)

I see. Then you refuse to back up your claim with data. ...IMHO (Talk) 21:56, 21 June 2006 (UTC)

Maybe take a look at the table at the beginning of the half-life article. For a half-life of 50 years, after 4 half-lives (200 years), 1/16 = 6.25% of the particles will remain. 128.197.81.181 22:39, 21 June 2006 (UTC)

Amending previous answer: After further research (i.e. the discussion on the half-life talk page), I now believe user IMHO's question is simply this: Like a non-reproducing population of humans, after a sufficient amount of time will a specific amount of a substance with a given half-life disappear completely? User IMHO's request for a table is particularly confusing given that (s)he generated exactly the requested table in an article that is up for deletion. Nevertheless, the answer seems to be that as a non-reproducing human population would not necessarily be described as exponential decay, the two processes are not the same, even though both processes may eventually end when all elements of the original collection (humans or, e.g., C-14 atoms) have decayed (barring unlikely quantum effects of a human coming back to life or an N-14 turning into a C-14). 128.197.81.181 23:16, 21 June 2006 (UTC)

The answer is false, and quite obviously so. If a non-reproducing human population decayed the same way unstable particles do, a human population of initial size $N$ would, in a period 3 times the median human life span, reduce to $N/8$. Now I don't know what a good estimate for the median human life span is, but 70 years should not be too far off. The probability than a random person will still be alive after 210 years is not 12.5%, it is (for all we know) 0%!--72.78.101.61 02:30, 22 June 2006 (UTC)

(rewrap reply to 03:15, 22 June 2006) If you start with 10 items with a half-life of 50 years, then after 200 years, there is approximately a 52.4% chance that all 10 decay, 35.0% that 1 is left, 10.5% that 2 are left, 1.9% that 3 are left, 0.2% that 4 are left, and the rest are insignificant. Now compute .350 + 2*10.5 + 3*.019 + 4*.002 and tell me what you get. Melchoir 03:40, 22 June 2006 (UTC)

You must first provide the basis for your statements. I can say that 1 = 0 but if I do I think whoever I say it to might be entitled to the courtesy of my telling them why and showing them step by step my reasoning. Otherwise they have every right to reject what I am saying and interact with me no more. ...IMHO (Talk) 03:57, 22 June 2006 (UTC)

I'll tell you how I got 35.0% if you tell me the result of the computation I asked for. Melchoir 04:01, 22 June 2006 (UTC)

I don't care how you got it and I am not interested in solving puzzles or playing games. Please find someone else to play games with. ...IMHO (Talk) 04:07, 22 June 2006 (UTC)

Rather ironic, from someone who seems to have quite a grasp of mathematics. Here you go, though:

First, Melchoir has an error ("2*10.5" should be "2*.105"). After that, though, it's just summed probability. The average number of atoms remaining is equal to P(0)*0 + P(1)*1 + ... P(n)*n, where in this case n=10.

The probability P(x) is C(n,x). Sum all those terms and you get 0.625 atoms remaining, on average, in your example. As I noted way back in the first response, though, this is probability, not reality. The number of atoms must, of course, be integral, and is most likely 0 or 1 (an 82.5% chance, if my math is correct).

Does that clarify things? — Lomn | Talk 04:13, 22 June 2006 (UTC)

Then stop acting as if you knew what you're talking about. Melchoir 04:10, 22 June 2006 (UTC)

He's not playing games; he's trying to explain to you why not all of the particles will necessarily have decayed even after the expectation value generated by the half-life calculation falls below 1.

Given a half-life of 50 years and an elapsed time of 200 years, we have a total of 4 half-lives elapsed. The probability of a given particle undergoing radioactive decay during any fifty-year period is 0.5, by definition. The probability of a particle surviving four such consecutive periods is therefore (0.5)⁴, or 0.0625 (6.25%); the probability of one particle decaying is therefore 1-0.0625, or 0.9375. The probability that all ten particles will decay is therefore 0.9375¹⁰, or 0.5244 (52.44%): the value Melchior gives above. Similar calculations give the remaining figures (it's an example of a binomial distribution). There's even a small probability (about 10^-12) that none of the atoms will have decayed. TenOfAllTrades(talk) 04:22, 22 June 2006 (UTC)

At this point in the discussion the issue seems to be one of certainty versus probability. In fact I think we agree that they are opposites. When one is uncertain one turns to probability for a reasonable answer but when one is certain one would be foolish to turn to probability for the answer. I am certain that isotopes which undergo radioactive or Beta decay as individuals and therefore as a population are not immortal unless you have an infinite supply. Thus if you have a closed container of Carbon-14 which can not be penetrated by cosmic radiation or influenced in any way such that Nitrogen-14 within the container will be converted to Carbon-14 that the Carbon-14 contained within the container will eventually perish, die, drop dead, cease to exist, go kapoof, say bye bye, bite da bullet, kick the bucket, fall off the cliff, go kaplunk, join King Neptune, ride the ferry, antagonize da horn, get whacked, meet it's maker, build a pyramid, get blue screened, sweet repose, see the henchmen, walk the plank, push up the lillies, etc. ...IMHO (Talk) 12:16, 22 June 2006 (UTC)

---

You still appear to misunderstand the vital role probability plays in radioactive decay (in fact, it's solely and entirely driven by probability). While it is exceedingly likely that radioactive decay eventually consumes all non-replenlished atoms, that cannot be said with mathematical or scientific certainty. Aside from that minor quibble of vocabulary, I think we've now resolved your original question. — Lomn | Talk 13:02, 22 June 2006 (UTC)

How about this thought experiment: Assume that radioactive decay is random (as it appears to be) and that each atom's decay is independent of each other atom (as it appears to be). The universe is very large and there will be a *lot* of Carbon-14 (for example)—enough Carbon-14 to last a *very* long time. If we take 15 atoms of this large amount of Carbon-14 in the universe and put the in an inpenetrable container (no gamma rays, etc.) what will happen? The answer is that we cannot say for certain. Even though we know that Carbon-14 is unstable we cannot predict (with certainty) when or if these 15 atoms will ever decay. We might have, by chance, picked the few atoms that basically out-last the universe. We will find (at the least) that our small number of atoms on the whole of human experience appear to never decay--that they last forever. This is the problem with your desired example. You (IMHO) are applying your intuition to a random process and humans, generally, have poor intuition when it comes to randomness—it appears to not be in our genes. —Bradley 17:45, 22 June 2006 (UTC)

The question asked if isotope atoms die out in the same manner as living things and that's clearly false. Even as a metaphor the comparison is weak. Peter Grey 22:29, 22 June 2006 (UTC)

I think they won't die out. The lifetime of atoms of a radioactive material have an exponential distribution which will cause that you need lots of time for many atoms together to all die out. This is quite unlike living organisms, which age with time and die more easily as they're older. Radioactive atoms don't get older. – b_jonas 09:24, 23 June 2006 (UTC)

DVD decoder?

Having installed a DVD optical drive and Windows XP Media Center 2005 Edition on a new computer, I am unable to play content-protected DVD's (although unprotected DVD's can be painlessly played). Windows Media Center, Windows Media Player as well as other DVD software show various error dialogs, complaining about problems with the decoder. My guess is that the problem may be resolved by purchasing either of the following products: CinePlayer DVD Decoder Pack or NVIDIA DVD Decoder. I am right? Is it worth a try? --Andreas Rejbrand 20:45, 21 June 2006 (UTC)

It might be that your DVD drive is set to the wrong region. Do the messages give any hint of this? See if you can check the region. Many DVD drives allow you to change the region up to five times; after that (a hardware limit) you are stuck in the last region you chose. Notinasnaid 21:11, 21 June 2006 (UTC)

Thanks for your respons, but, actually, I've already checked that, and it is valid. --Andreas Rejbrand 21:20, 21 June 2006 (UTC)

The software you've listed may fix the problem. I notice that the NVIDIA one has a 30-day trial, might I suggest you see if that fixes the problem before you spend money? — Lomn | Talk 21:24, 21 June 2006 (UTC)

Seems very wise indeed. Thanks! --Andreas Rejbrand 21:31, 21 June 2006 (UTC)

You might try using VLC, which is usually not picky about playing things. If that works, you can rule out issues with your drive, and probably won't want to continue to mess with Windows Media Player. Trollderella 21:59, 21 June 2006 (UTC)

Thanks for your answer. (Actually, however, I think Windows Media Player and particularly Windows Media Center are great software.) --Andreas Rejbrand 22:05, 21 June 2006 (UTC)

Regardless, the advantage with VLC is that you do not have to worry about codecs issues and the like. This will help to establish a base line to work out what the problem is. If your drive or the disc is broken, then it's no use fooling around with other issues Nil Einne 08:13, 22 June 2006 (UTC)

De gustibus non est disputandem. Did you get it working? Trollderella 22:18, 21 June 2006 (UTC)

It works in VLC, but that does not completely solve my problem. I want it to work in WMC. --Andreas Rejbrand 10:34, 22 June 2006 (UTC)

WMC does not have its own DVD decoders. You are required to get third party codecs for it. I know Dell computers come with Cyberlink PowerDVD preinstalled, but I decided to uninstall it and as much preinstalled software as I could, and then eventually reformatted. This is the official WMC DVD decoder page, but they cost money. This is why I use VLC religiously. --Chris 15:23, 22 June 2006 (UTC)

I see. Well, at least they aren't excessively expensive. --Andreas Rejbrand 15:47, 22 June 2006 (UTC)

Metal Plate in Head Questions

1. First of all, if someone is shot in the head and miraculously survives, is a metal plate inserted into the skull the normal procedure to repair the damage?

more importantly,

2. Let us assume hypothetically that a person has been shot in the head by a 10mm bullet, and survives. Let say it 'grazed' his head and pulled some of his skull off, but left his brain competely intact. Would a doctor use a metal plate in this instance to repair the missing skull fragment(s)? How would he go about inserting it? How long would it take for the wound(s) to completely heal and for the plate to be completely integrated into his skull?

and finally,

3. If a man with a metal plate in his skull was shot directly, at a 90 degree angle of impact from the tip of a 9mm full metal jacketed bullet, in the same spot as the plate is inserted in his skull, would the metal plate protect him from the bullet? What would the effects be on the man? Would he be knocked unconscious, or not? Would the bullet ricoshet? If the plate does protect him from a 9mm bullet, what is the maximum full metal jacketed caliber that the plate would protect him from (.357, .44, etc.)?

Thanks, 69.138.62.148 22:10, 21 June 2006 (UTC)

None of these questions are easy to answer, since traumatic head wounds are very unpredictable. The effect, recovery and treatment depend greatly on the specifics of the injury. The balistic properties of metal plates in the context of head injury are likewise not easy to predict. I assume that you are researching a novel, since I don't want to contemplate the other possibilities. Go for it - it's certainly not impossible that a man with a plate in his head could be saved by a freak balistic trajectory. Trollderella 22:17, 21 June 2006 (UTC)

To answer:

1) Yes, if the original skull fragments are unworkable.

2) It depends entirely upon the injury. Titanium plates are custom made to fit the skull (also full oseointegration occurs), and some insight can be given here at this link. i.e. the plates are screwed into existing bone (pictures of the screws here)

3) Bullet deflection will only occur at grazing incidences with such thin metal plates. At 90 degrees, the titanium plate probably won't even stop a .22 round. However, it is possible for a 9mm para at a high incidence (i.e grazing) to be deflected. This has been demonstrated with the guy who shot his friend's XBOX with a 9mm parabellum and it wasn't even scratched. As for higher calibres (including FMJ), it's even less likely, and for a .357 magnum to be stopped by this is just silliness.

Reply if you want further details. --Eh-Steve 08:43, 22 June 2006 (UTC)

As for being shot directly by a 9mm full metal jacket, a thick metal plate (you are talking inches, not millimeters) will absorb the strike, denting inward. However, to push against the bullet coming in, it also has to push against the skull where it is attached - likely crushing it on one side. So, assuming the plate is thick enough to keep the bullet from punching a hole right through it, the likely end-scenario would be that the weak side of the skull would cave in, causing the plate to fold inward (into the brain) and the smashed bullet fragments would go into the brain as well. I would expect more damage to the brain than having a 9mm hole punched through it. --Kainaw ^(talk) 14:18, 22 June 2006 (UTC)

Thank you to all for responding so throughly. In response to Trollderella's comments, I am indeed researching a novel, not planning an assassination or some such violent foolishness. From what I have read in the responses and through other research, it seems unlikely that a metal plate inserted in the skull via the normal medical procedures would protect a person from bullets flying at his or her head. However, seeing that I am writing a fiction novel, I may be able to exaggerate the strength of these plates, and a person's ability to stay conscious from trauma to the brain. Hopefully I will not have to exaggerate these factors to the point of rediculousness or, even worse, to the point that it breaks the readers suspension of disbelief. Thanks again to all. 69.138.62.148 21:45, 22 June 2006 (UTC)

Well, speaking of novels, some novel of Rejtő Jenő features a men who was protected from a gunshot to his heart by a metal plate he's placed there deliberately because he knew the antagonist would always aim there. – b_jonas 09:17, 23 June 2006 (UTC)

'Good' cholestrol

I want more of it. I read the article, which told me what it is, but not how to get more of it. What should I be eating more of? Thanks! Trollderella 22:14, 21 June 2006 (UTC)

Eat more: vegetables, fish, nuts, high glycemic index carbs, and monosaturated fats. Eat less: polyunsturated fats, hydrogenated fats, junk food. Consider taking omega fatty acid supplements (fish oil, evening primrose oil, seabuckthorn oil) and lecithin.--Anchoress 22:24, 21 June 2006 (UTC)

Have polyunsturated fats had multiple comments by me removed from them ? :-) StuRat 03:23, 24 June 2006 (UTC)

Thank you very much - it might be good to add these to the articles on LDL and HDL. Trollderella 22:26, 21 June 2006 (UTC)

Garden of Eatin' chips and Lance crackers have good fats in them. —Keenan Pepper 00:56, 22 June 2006 (UTC)

What about Steakhouse of Eatin'? — The Mac Davis] ⌇☢ ญƛ. 01:38, 22 June 2006 (UTC)

I had a very low HDL (less than 10). I increased it through excercise and drastically increasing fish in my diet. By fish, I don't mean shrimp, crab, oysters... I mean things like salmon, whitefish, and bass. After a year of using the stairs (I work on the 12th floor) and having fish a minimum of 3 days a week, my HDL is now 22. --Kainaw ^(talk) 18:29, 22 June 2006 (UTC)

Becareful with too much fish though. They retain lots more toxins than the water they live in retains. Mercury is one of the things you'll hear about today, though I don't know how much truth there are behind this. --Russoc4 21:02, 22 June 2006 (UTC)

June 22

Bomb detection

What methods/devices does the military currently use to detect explosive devices? For that matter, what are most explosive devices (for instance those made by insurgents in Iraq) made of? How could they be detected? Is anyone developing an all-purpose IED detector? This has puzzled me, since it seems like a high-priority question for a budget-rich military, and not obviously infeasable. Some kind of radar or sonar device for scanning the road ahead? Thanks, --Bmk 00:26, 22 June 2006 (UTC)

My (limited) understanding about explosives detection is that you do it by chemical analysis of one form or another, either by having a bomb-sniffing machine of some sort or a bomb-sniffing animal of some sort (i.e. a trained dog). According to the "detection" section of our article on IED's (Improvised_explosive_device#Detecting_and_disarming_an_IED) attempts have been made at remote universal IED detectors but have not yet been successful despite a lot of funding going into it. --Fastfission 00:55, 22 June 2006 (UTC)

Living on a military base, I've seen a lot of cool stuff. The best they could do is a chemical sensor that senses certain chemicals commonly found in IEDs. But that would take a stationary explosive, that has a self detonation, instead of one where the bombmaster can detonate when he chooses. — The Mac Davis] ⌇☢ ญƛ. 01:37, 22 June 2006 (UTC)

I wonder if some kind of sonar-imaging with some computer-aided pattern recognition would do the trick. Thanks for the replies. --Bmk 01:46, 22 June 2006 (UTC)

There are many people around the working on this, the problem is that there is no way to tell exactly what explosive someone will use. While you can look for traces of common chemicals used in bomb making (that is what they are doing in airports when they 'swab' your baggage), you need to get close enough to take a dust sample, which, on a battlefield isn't going to help you much. For a simpler case, look at some of the methods and equipment used in mine detection - there is not 100% reliable way to detect mines still. A major issue with IEDs is that you have to be able to detect them before you get within the effective blast radius for the information to help you. It's a difficult problem indeed. I doubt sonar would help, because it's not very accurate, and you don't know in advance what shape the explosive is. Trollderella 02:11, 22 June 2006 (UTC)

It woiuldn't work fast enough. I think you are talking mainly about rockets and such? That's the problem. Projectiles move way too fast for detectors, even with today's best technology. — The Mac Davis] ⌇☢ ญƛ. 02:31, 22 June 2006 (UTC)

No, I was thinking of buried or concealed explosives, like those used to attack convoys along roads. --Bmk 12:13, 22 June 2006 (UTC)

The difficulty in spotting IEDs with a visual method (like sonar) is that by definition they are improvised and probably non-standard in shape (though I suppose if you could x-ray something you would have an idea of its internal structure and texture and perhaps do something with that...). Using a chemical method improves on that a bit since there are a limited number of materials they are made from. It'd be really awesome if you could combine the two -- if you were able to "see" certain chemical concentrations in a visual way ("Gosh, an awful lot of ammonium nitrate over in that area..."). But I am not a scientist. :-) --Fastfission 16:55, 22 June 2006 (UTC)

A different, but related topic you may also be interested in missile or airborne threat detection. The standard techniques for detection of such threats include radar (bouncing a radio wave off of the reflective metal); infrared detection of heat (hot gases from a jet or rocket engine); or optical surveillance. Often, several tracking systems are combined to maximize detection of the threat. Finally, automated systems attempt to follow and destroy the target. Such areas are actively researched and advancements are continuously made. Nimur 19:04, 23 June 2006 (UTC)

Need help in physics

If this is house that has vents And there are also vents at the soffits then what is the difference in pressure if the wind 65mph comes from the side of the house. Say wind comes form North to South then what is the difference in pressure between North and South part of the house. Plus how can I figure out the difference in pressure between attic and exterior. Hope you will be able to help me. Kind regards. Thank you You can write to me directly at address removed to prevent spam Your help is greatly appreciated.

What the heck are "the soffits"? --Bmk 01:44, 22 June 2006 (UTC)

Soffit. --LarryMac 17:58, 22 June 2006 (UTC)

Oh my god, why do you have 65mph winds? Are you just meaning "hurricane speed winds?" I can't imagine you regularly experiencing them. As for your question, there is no way to tell without measuring because it would be tough for you to convey to use the schematics of your vent system and erm... soffits. The pressure will be greater on the north side of the house than the south. — The Mac Davis] ⌇☢ ญƛ. 01:49, 22 June 2006 (UTC)

HA! I KNEW this would come in handy some day! *gets out his pocketbook because he he's had 3 Palms and they all sucked*

Force = 0.004 x (The area of the wall) x (Windspeed)²

That's F=0.004Av² --mboverload@ 02:18, 22 June 2006 (UTC)

Nice formula, but I was thinking he ment air pressure. Now that I read it again, you may be right. — The Mac Davis] ⌇☢ ญƛ. 02:35, 22 June 2006 (UTC)

If you simply the problem a bit, ignoring compressibility (reasonable at these windspeeds) and sofftis (which I have no idea what they are) it boils down to stagnation pressure, which is ${\frac {1}{2}}\rho V^{2}$, where $\rho$ is the air density and $V$ is the wind speed (in metric units, please!). The result will be in pascals. So the pressure on the upwind side of the house will be the ambient pressure (current atmospheric pressure) plus the stagnation term I just quoted, and the pressure on the downwind side will be the ambient pressure - thus, the pressure difference is the stagnation term. The difference in pressure between the attic and the outside will be the same. — QuantumEleven 06:20, 22 June 2006 (UTC)

As to what soffits are, there is a good reference source on the web for all kinds of things. Here is a link to its entry on soffits: [9]. --Lambiam^Talk 09:15, 22 June 2006 (UTC)

Leg length

Once in a while one leg will feel longer than the other. The effect will pass in a few hours, but what could be the cause? - RoyBoy ⁸⁰⁰ 01:53, 22 June 2006 (UTC)

Some kind of pinched nerve is my guess. Like it says at the top of the page, asking a real doctor - your doctor - is 10000x better than here =D --mboverload@ 02:13, 22 June 2006 (UTC)

Then again, some of us are doctors. — The Mac Davis] ⌇☢ ญƛ. 02:36, 22 June 2006 (UTC)

Was that an implication that you were a doctor, at 14? Philc _T^E_C^I 13:26, 22 June 2006 (UTC)

I heard that one of legs is actually shorter than the other (I think it is the right leg that is shorter). That is supposed to be the reason why the guys lost is desert go in big circles, even if they think they are walking along a straight line. I am not sure about this, though -- Wikicheng 04:00, 22 June 2006 (UTC)

One leg is almost always shorter/longer than the other. Usually the difference is quite small, and it can change from day to day as the soft tissue in the joints is stretched or compressed. Differences can also arise due to differences in the lengths of the major bones of the leg; in those cases corrective orthotics or even surgery may be required for a normal gait and to stave off posture-related problems down the road. TenOfAllTrades(talk) 10:52, 22 June 2006 (UTC)

How long should a man's legs be? Long enough to reach the ground.

Long enough to reach his torso.

Whose legs are you feeling? --Dweller 13:30, 22 June 2006 (UTC)

Biological Evolution versus Intelligent Design

A recent revival of the anti-evolutionary "argument from design" holds that biochemical pathways are too complex to have evolved, because all intermediate steps in a given pathway must be present to produce the final product. Critique this argument. How could you use the existing diversity of metabolic pathways that produce the same or similar products to support your case?Patchouli 02:17, 22 June 2006 (UTC)

Similar to the "How do different animals have different number of chromosomes"? There might not be an answer, but good luck. I'm a believer in Evolution but it does have some problems because we still know quite little about biological systems. In fact, I think they just had to revise how they thought some part of a cell worked a few months ago. --mboverload@ 02:20, 22 June 2006 (UTC)

Is this a homework assignment?--72.78.101.61 02:49, 22 June 2006 (UTC)

• Yes.Patchouli 03:24, 22 June 2006 (UTC)

Congrats on the honesty. --Dweller 11:43, 22 June 2006 (UTC)

The fact that we do not know everything about biological systems does not mean "evolution has problems". Almost everything we know about the workings and inheritance of biological systems we have learned since 1860. Every major new discovery since Darwin has supported or is compatible with the basic concepts of evolution. You cannot name a single important new aspect of understanding of animal physiology, cell biology, or genetics that is incompatible or contradicts it. It is the single most useful concept about biology introduced in the last 2 centuries. alteripse 03:40, 22 June 2006 (UTC)

The Talk.Origins Archive website has a huge collection of standard creationist claims and refutations thereof...might be worth a visit. DMacks 04:07, 22 June 2006 (UTC)

You are correct Alteripse...I'm not sure what I was trying to get at. Hm. --mboverload@ 07:19, 22 June 2006 (UTC)

Second reading the TalkOrigins Archive. Two points to start you off:

• A particular pathway might not produce the same endproduct if a component is removed - but perhaps the resulting product is nearly as good at the task - or is useful for something else entirely.
• The creationist argument assumes that the only way for evolution to operate is to add components to a pathway - but there are other ways for mutations to occur: joining existing pathways, stitching pathways together, altering steps; in particular, removing steps from longer pathways.

EdC 11:06, 22 June 2006 (UTC)

That should read "One creationist argument is to assume...". There's no shortage of creation arguments and no shortage of refutations. And vice versa for evolution. That's what makes is so much fun. All you need to remember is that both are correctly called "theories". Could be that neither is right, thought about that yet? <grins> --Dweller 11:43, 22 June 2006 (UTC)

Creationism isn't a "theory" – certainly not in the scientific sense – as it is not falsifiable. It's arguments against the legitimate theory of evolution almost always amount to pointing to the next gap in scientific understanding, and saying "Oh yeah? I bet you can't explain this! Therefore, there must be a Creator (ahem...Intelligent Designer...)." When an explanation is forthcoming, creationists can just point to the next gap in understanding. See God of the gaps. TenOfAllTrades(talk) 11:55, 22 June 2006 (UTC)

Not sure what you mean by "legitimate". Do you mean there's one evolution theory that's correct and many others that are wrong, or do you (as I suspect) mean that evolution is Truth? As I understand it, you want to have your cake and eat it. You want to decry creationism because it cannot be disproved and you want to knock creationist attempts to disprove evolution! Let's face it. It's an argument neither side will win. Probably because neither is true and really the world was made by Slartibartfast. --Dweller 12:12, 22 June 2006 (UTC)

"Legitimate" probably being an actual "theory" in the scientific sense. Note the context is as a counterpoint to creationism not being a "scientific theory". An oft-seen creationist ploy is to say "see? even scientists themselves admit that evolution is just a 'theory', so our competing theory is just as valid", forgetting (to be generous about their motives) that the scientific meaning of "theory" is different than the common-language word. DMacks 15:30, 22 June 2006 (UTC)

Why are you so sure that creationism could never be disproved? --Dweller 16:29, 22 June 2006 (UTC)

Because it generally doesn't allow for testable questions. (See our article on falsifiability to understand the specific relevance of this to the definition of a "theory") Many individual statements of Creationists can be disproved, of course, but as a whole when you have a system predicated upon an omnipotent agent then you can explain away anything. --Fastfission 16:50, 22 June 2006 (UTC)

(moving back here, cos I'm not a right-winger)

You couldn't explain away Slartibartfast's home movies?

It's a pointless argument anyway. It doesn't matter how good either sides proofs are... the creation lobby will never concede that evolution is truth and the upholders of evolution will never concede that the world was created by a mysterious omnipotent being. With or without a long, white beard.

If creationists ever came up with a "winning" argument, science would be just as slippery as you aver creationists are... I doubt you'd see blokes in white coats rushing out to their nearest church/synagogue/mosque/long pole in the middle of the desert. The scientists would at best acknowledge that evolution was a flawed theory and they'd then sit back and wait until someone came up with a better one, while continuing to insist that creation isn't even a theory. --Dweller 18:42, 22 June 2006 (UTC)

Not quite. The ends of scientists and creationists are markedly different. Science is looking for understanding and predictability. If god or UFOs or the Flying Spaghetti Monster appeared and explained that they were soley responsible for every species on Earth and all of our evidence for Evolutionary Theory was fabricated, scientists would think that was great and they'd want to understand how the "designer" did such an amazing thing. We would take the new evidence (which would have to be extraordinary) and try to figure out every little detail of its operation. Creationists do not have that end. They just don't want there to be thoughts and ideas that contradict the word of their god as presented to them in form of the bible.

Additionally, it's really not quite that funny—in the United States, at least. It's really more along the lines of shocking and horrifying. Here we have ignorance versus reason and in the minds of the masses the winner is not clear. What will the creationists see as the next threat to their way of life? —Bradley 19:11, 22 June 2006 (UTC)

biochemical pathways are too complex to have evolved is an assertion with a precise mathematical requirement. Without the math proving that it's "too complex" and identifying all conceivable intermediate steps, the argument is a merely a failure of the human imagination without scientific merit. But hey, if the creationists could prove it, then we'd have to say they might be on to something... Peter Grey 22:39, 22 June 2006 (UTC)

It's possible that you might want argument from poor design, an opposite (somewhat) observation for the opposite conclusion. —AySz88\^-^ 04:34, 23 June 2006 (UTC)

Equation out of the Middle East

I: Since at least the year 1300, no human out of the Middle East has ever contributed a mathematical equation or formula.

Joe: You are wrong; this can't be. You are offending the intelligence of Middle Easterners.

I: This is the bitter truth. I never said there are no mathematicians or scientists who understand every equation or formula that has been discovered. I just say that there is not been an original contribution since at least 1300. To prove me wrong, I ask that you name a specific person with the specific equation that he came up with like the Schrodinger equation.

Joe: I am at a loss.

I wish to verify with more knowledgeable people whether I am correct. I appreciate any response in advance.Patchouli 02:25, 22 June 2006 (UTC)

May be right, since around then they have not contributed much to world society. — The Mac Davis] ⌇☢ ญƛ. 02:37, 22 June 2006 (UTC)

Hmm, let's see... the Turkish mathematician Cahit Arf has some things named after him. Does that count? —Keenan Pepper 02:41, 22 June 2006 (UTC)

I couldn't find a specific equation. I don't want principles. In addition, Turkey is generally considered European according to the Middle East article.Patchouli 03:18, 22 June 2006 (UTC)

Mergelyan's theorem is named after Armenian mathematician Sergey Mergelyan. —Keenan Pepper 02:45, 22 June 2006 (UTC)

And don't forget Israeli cryptographer Adi Shamir, the S in RSA. —Keenan Pepper 02:49, 22 June 2006 (UTC)

Do half-Middle Easterners count? Michael Atiyah is half Lebanese. --ColourBurst 04:52, 22 June 2006 (UTC)

I personally believe Michael Atiyah is one of the greatest living mathematicians; nevertheless he was neither born in Lebanon nor received any substantial schooling in the Middle East.Patchouli 05:20, 22 June 2006 (UTC)

I have a little trouble with this. The original statement was "no human out of the Middle East...", not "no human born and trained in the Middle East...". One implies something about the people; the other implies something about their circumstances. --ColourBurst 07:16, 22 June 2006 (UTC)

In the vein of literalnesss, a person born in Great Britain has not sprung out of the Middle East. One could even argue that Martin Van Buren was Dutch, Steve Jobs is Syrian, and so on.Patchouli 08:11, 22 June 2006 (UTC)

• I am interested in the Middle East composed of Arabs, Persians, and Afghans. Definitely not someone from a former USSR state; while Israel is in the Middle East, I should have said excluding Israel.Patchouli 03:18, 22 June 2006 (UTC)

Until now, I've assumed good faith but since Israel IS in the Middle East, your question is undermined. Are you asking about anyone born in a Muslim country and if you are, why not say so? Sadly, you've given me evidence to subdue my good faith assumption and suspect your motives. --Dweller 11:52, 22 June 2006 (UTC)

• Yes; a Muslim country in the Middle East — since I do not fear betting that no one born and educated in Indonesia, Nigeria, Sudan, et cetera ever came up with an equation. I made the mistake in good faith because I should have said a Muslim country in the Middle East. Therefore, I apologize for this error. I thought maybe there is an obscure equation that I know nothing about and I have no motives to belittle any nation. I basically wanted to extract a fact since I am not infallible and don't know every equation.Patchouli 02:11, 23 June 2006 (UTC)

• No equation is going to be fairly hard to verify, but Mac Davis is correct above: there's a marked shift from possibly the most advanced civilization mathematically around 1000 CE to a near-complete lack of scholarly interest by 1300 or 1400 CE. I would expect that blanket statements today are incorrect, though, as (even if the culture in the Middle East isn't yet shifting) students from the region are increasingly studying at European and American (and other) institutions where good mathematical work is being produced. I would expect that such work also continues in regional institutions, and that it has to some degree or other all along.

  Quick summary: the absolute is almost certainly false. The general case (the decline of Middle Eastern contributions to mathematics) is almost certainly true. — Lomn | Talk 04:33, 22 June 2006 (UTC)

• I already know about Mahmoud Hessaby, for instance, yet over the past few weeks my sporadic research on him did not unearth a single equation.Patchouli 05:20, 22 June 2006 (UTC)

Ahmed H. Zewail Egyptian, Nobel Chemistry. Abdus Salam, Pakistani , is that close enough? Nobel, physics, ElectroWeak theory --GangofOne 06:37, 22 June 2006 (UTC)

• I didn't know who Ahmed Zewail was; this anwer is on target especially since Egypt is always classified as a Middle Eastern nation.Patchouli 07:24, 22 June 2006 (UTC)

• I thank everyone for its responses notwithstanding my further request that if there is a specific equation discovered by a Middle Eastern individual that you provide a link for it or paste it hereon.Patchouli 07:32, 22 June 2006 (UTC)

A non-Israeli Middle Eastern, you request (above). What about a Jew born in, say, Iraq? Or a Christian born in, say, Oman? --Dweller 16:33, 22 June 2006 (UTC)

• Fundamentalism & mathmatical advances don't exactly go hand-in-hand. Mayor Westfall 12:25, 22 June 2006 (UTC)
  • It is worth differentiating between authoritarianism and fundamentalism in the case of the Middle East. Much of the Middle East is under some form of authoritarianism which is not rooted in religious fundamentalism (i.e. Syria). --Fastfission 16:46, 22 June 2006 (UTC)

Many pioneers who came up with equations were born and raised in the authoritarian regime of the Soviet Union.Patchouli 06:06, 23 June 2006 (UTC)

• • • Well it was the collapse of early Islamic philosophy at the hands of opposition from key scholar/theologians like Al-Ghazali that triggered a return to theological fundementalism and the abandonment of scientific thought circa early 12th century AD. Just as a form of Christian fundamentalism might be said to have ushered in the dark ages in Europe, fundementalism played a key role is impeding the progress of science and mathematics in the Islamic world as well. Dragons flight 21:45, 22 June 2006 (UTC)

• Even Al-Khwarizmi in 800s CE did not contribute an equation that I can find. I have concluded that he simply rehashed Diophantine's Arithmetica in Arabic.Patchouli 00:33, 23 June 2006 (UTC)
  • I think he contributed a technique (or several) for solving equations. You should remember that equations are not a particularly important output product of math research. If anything, theorems would be what you'd want to look for. Someone like Galois who is very important, contributed the fact that there's no equation of a certain form, and so if he happened to be middle-eastern you wouldn't ve counted him either, I take it? --Ornil 03:55, 23 June 2006 (UTC)

No; I wouldn't count Galois notwithstanding his enormous accomplishment. As I stated first, I am simply interested in a meaningful equation with a principle - like a theorem - tied to it like the Einstein photoelectric equation or the Compton wavelength equation. This is what I am searching for.Patchouli 04:37, 23 June 2006 (UTC)

Is there any relevance to this question? Or is it just a very contrived way to point out that the heyday of mathematics in the Islamic world is a thing of the past? Formulating it as a question suggests sincerity. Similar question then. How does Russian scientific literature fare since the fall of the Soviet Union? It used to constitute 1/3 of the world's scientific literature. But I don't know what it's like now. So a legit question? Or am I trying to make a point, whithout actually making it, so that that can not be held against me? (sneaky, sneaky) DirkvdM 08:16, 23 June 2006 (UTC)

• Not necessarily since I learned who Cahit Arf and Ahmed Zewail are as a result of this conversation. I will close this discussion because it is becoming very lengthy without achieving any intellectual purpose.Patchouli 10:19, 23 June 2006 (UTC)

Oi! I'll decide when this discussion is over! Ok, it's over now. :) DirkvdM 17:56, 23 June 2006 (UTC) No, it isn't .... DirkvdM 06:08, 24 June 2006 (UTC)

The biggest problem is that you're mistaking two claims:

1. No equations were developed in the Middle East
2. No Western educational system teaches about Middle Eastern mathematical developments.

I have heard from reputable research historians who specialize in the History of Mathematics that an entire career can be made simply by learning Arabic and proceeding to translate literally thousands of archived documents which are essentially un-studied by Western historians. The biggest problem is that concurrent developments in the Middle East during the 12th through 19th centuries went largely untranslated because of the animosity and xenophobic divide between Arab and European cultures. To claim that no mathematicians (or equations) came from that region is a very strong argument based solely on the premise that we do not know of them. Nimur 19:21, 23 June 2006 (UTC)

Of course, something similar goes for Russian scientific literature, and I forgot to mention that. Chinese literature too, and that's 1/5 of the world's population. Now China has always stuck to its own affairs, so it's not that likely they will translate it themselves (who for?). And with the way thingsa are going in Russia, it doesn't seem likely it will happen there either. But many Arabic countries have plenty money, so they can afford to hire people. But then I suppose that is what you are saying. I'm unemployed and good at languages. Thanks for the tip! Where do I apply? :) DirkvdM 06:08, 24 June 2006 (UTC)

Most effecient device

What is the most effecient device for converting electricity to light? I heard that they use LEDs in some torches which give light of brightness comparable to the incandescent bulbs. Are the LEDs most efficient? -- Wikicheng 04:13, 22 June 2006 (UTC)

I don't want to commit to most efficient, but LEDs are more efficient than incandescent bulbs. LEDs also have an advantage in being practically unbreakable. — Lomn | Talk 04:18, 22 June 2006 (UTC)

The nuclear bomb. (In addition to electricity, a minimal amount of mass is also converted to light. There is also considerable heat by-product.) Hope this helps.

But like you said, a minimal amount of mass is also converted to light, so they would be terribly inneficient. Philc _T^E_C^I 10:36, 22 June 2006 (UTC)

I don't know how efficient they are, but arc lamps are fucking bright. That article also has a nice table at the end, which is a template I'll insert here:

You might want to look through those. You should also consider the fact that it probably matters to you what frequencies energy is concentrated in (for example, reflective biker gear I heard is brighter because it takes many ambient frequencies and redirects the energy into one bright [say, orangey] wavelength, obviously not reflecting more energy than it absorbs however seeming much brighter). In theory, of course, any electricity you're not producing heat with is 100% converted to "light" but is this enough to tell you how efficient it is at the part of the spectrum you're interested in producing light at?

I was looking at a device which can probably used in a hand torch (flashlight). I can not include a nuclear bomb in this. Moreover, I an trying to convert electricity and not mass to light. Anything close to white light is welcome -- Wikicheng 11:38, 22 June 2006 (UTC)

Could you fit some glow worms in your hand torch? --Dweller 11:55, 22 June 2006 (UTC)

Not a bad idea though! :-) -- Wikicheng 12:56, 22 June 2006 (UTC)

Apparently Organic light-emitting diodes can be made almost 100% electricity-to-light, but very much "in development". Otherwise low pressure sodium Electric lights are the most efficient, but the light is pure yellow - no other colours - and the tube is large. For torch size the white torch LEDs are reasonably cheap, but seem to be less efficient than flourescent lamps (40 lm/W vs 50 lm/W). I haven't seen a standard torch-size flourescent source that gives bright enough light though, they all use pretty long tubes. So LEDs seem the best for smaller torches, fluorescent tubes for larger battery powered area lighting. A 2 or 3-cell (1.5V cells) torch can be converted to LED by buying an LED and fitting it in the reflector without any other conversion (not a bright light though). --Seejyb 22:58, 22 June 2006 (UTC)

Well, that very much depends on the brand of light. :) Some of the tactical flashlights have LED conversion kits that are still very bright flashlights. :) kmccoy (talk) 10:32, 23 June 2006 (UTC)

Amount of water in dew

In a cubic meter of air with a humidity of 70% how many liters of water would they be in it? and what is the formula for calculation?

Regards, Albert W Howard

Well, since 70% means a relative humidity, it's going to depend on the temperature. A cubic meter of air can hold more liters of water if it's warmer. There's some information at Humidity, but probably not all that you need. Melchoir 04:25, 22 June 2006 (UTC)

I googled "how much water can a cubic meter hold" and one of the results is this everything2 write-up (remember everything2? Ah, the days before wikipedia...):

         Air temp,   Water content of
         deg C       saturated air,
                     gram/cubic meter
         --------    ----------------
         -10               2.1
           0               4.8
          10               9.4
          18              15.4
          20              17.3
          30              30.4
          40              51.2
          50              83.0
                         .....
          90             423.5

so as you can see, you need to know the temperature. Read the writeup I linked, it's very interesting. Unfortunately, I don't know if "70% humidity" or saturation is just 70% of the gram weight of the water, since it's conceivable that another scale (logarithmic or something, or volume, or...) is used. This is what relative_humidity says: "Relative humidity is the ratio of the amount of water vapor in air to the maximum amount of water vapor that could be in the air if the vapor were at its saturation conditions." I wish it would explicitly state that this is the same as grams of liquid water, or volume of liquid water, or mols of h2o or whatever. Anyway, I think it's safe to just multiply the gram/cubic meter by 70% to get 70% relative humidity, after deciding what temperature you want it at. Be sure to convert to liters of water / cubic meter, since that's what you asked for! 82.131.191.135 10:29, 22 June 2006 (UTC)

Meaning of "MMgy"

Please expand MMgy; apparently it is a unit of measure of liquid fuel.

From Google, it appears to mean "million gallons per year". Melchoir 05:34, 22 June 2006 (UTC)

Update: I've created Million gallons per year and MGY, with appropriate redirects. Melchoir 05:52, 22 June 2006 (UTC)

...and if someone knows which kind of gallon is implied, that would help. Melchoir 05:57, 22 June 2006 (UTC)

Binoculars

How can I measure or calculate the magnification factor of my binoculars?--Shantavira 07:11, 22 June 2006 (UTC)

It's going to be an even multiple, so maybe if you taped a piece of paper vertically to the wall opposite of you, after drawing a small rectangle at 1/10th size (for example, if your sheet of paper is 8.5 by 11 inches you could draw a 0.85 by 0.11 inch rectangle) in the same orientation, then you could look at the rectangle from one eye and the whole sheet of paper from the other eye and see if the apparent size is the same. Repeat with different ratios until you get the same apparent size. (It should be easy to judge, since if you do it right, the images come to different eyes but from the same plane and so they should line up nicely.) Try it and let us know.

Thanks. Yes, using both eyes makes a lot of sense. I hadn't thought of that. Rather than experiment with different sized rectangles I could use a whole line of sheets of paper as a scale, but in that case I might as well use the slats of my garden fence as a scale to compare with the magnified width of one slat. I have another pair of binoculars of known magnification, so I will try it using those first.--Shantavira 12:00, 22 June 2006 (UTC)

Yes it works. The paper rectangle idea turned out to be the simplest solution after all. --Shantavira 07:37, 23 June 2006 (UTC)

Environmental Question

Can you tell me about destructive distillation of wood?With Pictures please.--Saksham Sharma 11:03, 22 June 2006 (UTC)

This is an experiment that we do with our Year 8 classes (12-year-olds). The pupils heat some wood chips in the bottom of a test tube, and light the flammable gases which emerge at the mouth of the tube. Soon the flame dies down, and what is left inside the tube are fragments of charcoal and some brown tar. I believe that the flammable gas given off at the start is mainly methanol.G N Frykman 21:09, 22 June 2006 (UTC)

The Ultimate Speed Limit

I've heard that the Special Theory of Relativity's Ultimate Speed Limit applies not only to matter and material objects but to influences,disturbances,forces, and signals,etc of any sort.

I don't understand.I know that special relativity says that all matter and objects undergo changes as they move or travel and that they change back into their original state when they stop moving or stand still.I know that one of these changes is an increase in mass and that the mass of objects become infinitely large when they approach the speed of light.But that doesn't explain how things that are not material objects can't travel faster than light.

So how come things that are NOT matter can't travel faster than light?I mean, how can it and how does it apply to anything, not just matter and substances?

One way to look at it would be that if a signal could move faster than light, it would violate causality. Suppose you have two events, at different times and places: A) a person sends a signal, and B) the signal, arriving at its destination, causes a phone to ring.

Now, suppose you have some observers witnessing these two events. They're not all at the same place; some are moving at different, near-light speeds and in different directions. Because one's velocity affects time, according to special relativity, different observers will disagree about how much time elapsed between A and B. To one observer, there might be two seconds between A and B, while another observer might measure five seconds between A and B. However, as long as the signal traveled at the speed of light or slower, all observers will agree that B happened after A.

If the signal traveled faster than the speed of light, however, the math works out such that to some observers, it would appear that B happened before A! And it's not so much that B appears to happen before A; since observations in all reference frames are equally valid, B does occur before A for that observer. The effect would happen before its cause! Chuck 11:59, 22 June 2006 (UTC)

And this is the reason we have call waiting Mayor Westfall 12:18, 22 June 2006 (UTC)

The problem is that the non-matter things that carry forces, disturbances, influences, etc. are all either light or its cousins. Light, radio waves, x-rays, et al. are all photons with different energies—by definition they travel at the speed of light. Photons are actually responsible for all electromagnetic effects; all electric and magnetic fields are the result of photons being passed back and forth between objects, explaining why those influences can't travel faster than light—they are light.

Gravity is believed to be mediated by the exchange of particles called gravitons: massless particles that are like photons, but carry the gravitational force between bodies instead of the electromagnetic. The two other fundamental forces (the strong and weak nuclear forces) are similarly mediated by the exchange of particles. (There's funny stuff about the weak force and its associated particles that I don't want to go into; it doesn't affect the validity of this explanation, however.)

So we've got the 'stuff' of the universe that's made up of particles with mass that are limited (by relativity theory) to speeds less than the speed of light, and we've got the massless bits that mediate forces (interactions) which travel at the speed of light. All of the fundamental forces are associated with particles, so there isn't any way to generate an influence without using those particle intermediaries—all of which are limited by the ultimate speed limit. TenOfAllTrades(talk) 14:04, 22 June 2006 (UTC)

See faster than light, especially section "Apparent FTL". Conscious 18:36, 22 June 2006 (UTC)

This might not quite be revelant to the question asked, but if you were "travelling" at the speed of light, consider the Lorentz contraction of the rest of the universe - everything would be at zero distance. Then faster-than-light would mean you would have to start thinking about how to go zero distance in less than zero time. Peter Grey 22:53, 22 June 2006 (UTC)

But I was asking about how can and does it, I mean such a rule like that, apply to anything and everything, not just matter.Couldn't there be some kind of massless force-mediating particle, or some other unknown and undiscovered influence, which the changes associated with special relativity, and therefore the ultimate spped limit, doesn't apply to and occur in?

You can never conclusively know something undiscovered isn't there, but they haven't found any signs of one yet i.e. no known phenomena where an undiscovered faster than light effect is the best explanation. Peter Grey 04:14, 23 June 2006 (UTC)

Food

It seems like everything we eat is something that is made from a living soruce--e.g. animal/plant. Can anyone think of an example where this is not true? Also, why is this? Mayor Westfall 12:30, 22 June 2006 (UTC)

yeah, salt is the exception. I guess you could trace it back to the fact that humans don't do photosynthesis. (or, needless to say, organic atomic power).

The simple answer to your question is that the source of energy for animal metabolism is the energy released by breaking down energy-rich molecules such as glucose in cellular respiration, and some plant or animal has to create these energy-rich molecules (a.k.a. food) in the first place. Gandalf61 12:45, 22 June 2006 (UTC)

Some argue that petroleum is not from a living source(see abiogenic petroleum origin), though many believe it is from a living source. Many foods are made with petroleum. HighInBC 12:53, 22 June 2006 (UTC)

What foods are made from petroleum?! -Quasipalm 14:41, 22 June 2006 (UTC)

Pub grub. --Dweller 12:55, 22 June 2006 (UTC)

I wouldn't recommend it myself, but in Ancient Rome, lead salts were used as sweeteners. I have also read that in some countries, pregnant women eat clay as a supplement to their diet.--Tachikoma 16:56, 22 June 2006 (UTC)

What about something like Diet Coke? Both artificial flavors and sweeteners, but I'm not sure from what constituents these are produced from—could be peroleum distillates for all I know. —Bradley 17:49, 22 June 2006 (UTC)

Another bit of trivia: gold leaf is apparently non-toxic and can be eaten. I believe it was popular in the bad old days of Thatcher / Reagan. --The Gold Miner 18:08, 22 June 2006 (UTC)

Yes, E175 in Europe, see E number. You'll find a fair few inorganic substances on that list. Arbitrary username 18:49, 22 June 2006 (UTC)

But everything that was named is not nutritious. Conscious 20:39, 22 June 2006 (UTC)

Apparently there are bacteria that live in caves that no organic matter (or sunlight) reaches, which eat rock. Don't know about the metabolism details, though. DirkvdM 08:57, 23 June 2006 (UTC)

Perhaps you are thinking of SLiME? (Subserface Lithotrophic Microbial Ecosystem)Tuckerekcut 16:54, 23 June 2006 (UTC)

No, that's not it, but it reminds me of a different bacteria, fittingly named snottite. They corrode rock with their acidic drip, but don't eat rock. However, they eat sulphur, so it's still an answer to the question. DirkvdM 18:07, 23 June 2006 (UTC)

Well, if you're opening this up to non-humans, think of the ecosystems that have developed around undersea hydrothermal vents. These vents are also known as black smokers, and a variety of archaea and extremophile bacteria survive either from the dissolved chemicals in the magma-heated water itself, or even the faint glow that emanates from the black smoker.--Tachikoma 03:43, 24 June 2006 (UTC)

Water is not from a living source. It might contain living organisms or formerly living organisms, but it's not alive.

"not from a living source" ... I've done the math once and given the total volume of animals through time, I concluded that all water on Earth has at one point been piss. DirkvdM 06:12, 24 June 2006 (UTC)

Define "temperature equilibration"

Can someone please point me to a clear and concise definition of "temperature equilibration?" And specifically, does it occur when, say, a connecting door between two spaces--one warmer than the other--is opened, and the air allowed to flow between the two spaces? Thank you. --129.71.112.32 13:55, 22 June 2006 (UTC)

Temperature equilibrium is achieved between two bodies when their temperatures are the same, or equivalently, when both bodies' temperatures are no longer changing --198.125.178.207 14:03, 22 June 2006 (UTC)

I think you did not realize that the poster said "temperature equilibration". Look at the first few hits and see if the poster had the right definition. (Also, could pressure-temperature equilibrium of a gas figure in the definition?) 82.131.189.199 14:09, 22 June 2006 (UTC).

Buffalo Coin Value

On the Main Page there is a link to the article about the new Buffalo coin. It is a solid gold coin worth $50, but it is an ounce of gold. How can an ounce of gold be worth $50? Wouldn't it be easy to melt it down and sell it for pure gold? --Chris 15:18, 22 June 2006 (UTC)

The face value of the coin and its selling price are different things. The external links in the article mention the US Mint will sell the coin at price of gold + small premium; at today's price that would be in the USD 600 range. Later the "street price" will be what collectors are prepared to pay each other for the coin. 84.231.33.34 16:07, 22 June 2006 (UTC)

At $1.13 dollars per gram of gold, this thing weighs 31g, so you would lose money by melting them and selling the gold. Philc _T^E_C^I 16:53, 22 June 2006 (UTC)

I don't see how thats possible. Mostly because gold is currently USD18.72[10] per gram or USD582.30[11] per troy ounce (which is 31g). --Russoc4 17:51, 22 June 2006 (UTC)

My bad, I rephrase, at $582 per 31g, this thing weghs 31g and costs $800, so good luck on making a profit, you'll need it. Philc _T^E_C^I 23:55, 22 June 2006 (UTC)

Currently, the article mentions that its face value is $50, but it's issue price is $800. That means you have to pay $800 to get one American Buffalo coin from the U.S. mint. The $50 is not what you pay to get one from the mint; it's what the coin "counts as" if you use it as a coin. If you wanted to buy a $250 stereo, and for some strange reason you wanted to pay the store in American Buffalo coins, you'd need 5 coins. (This would be stupid, of course, since the market value is going to be at least the value of the actual gold in the coin, currently $582.30. But you theoretically could.) It's a bit confusing because with ordinary coins, the two numbers are the same--it costs $0.25 to get a quarter, and a quarter counts as $0.25 when you spend it. But those two numbers are not the same for all coins. Chuck 20:20, 22 June 2006 (UTC)

If you tried that at Best Buy, they'd probably have you arrested. --LarryMac 20:33, 22 June 2006 (UTC)

Thank you for explaining, Chuck, and thank you for making me laugh Larry :) --Russoc4 20:54, 22 June 2006 (UTC)

God that links funny, especially “It’s a sign that we’re all a little nervous in the post-9/11 world,”, what was he going to do with his smeared two dollar bill, give a policeman a paper cut!? I'm pretty sure a piece of paper has considerably less impact than a 777. Philc _T^E_C^I 00:04, 23 June 2006 (UTC)

Why does insulin stimulate glycolysis

I just read that insulin stimulates glycolysis - essentially the breakdown of glucose into energy. Why is this? It seems to me that this goes against the "normal" anabolic effects of insulin. Or is this simply what occurs in cell metabolism after glucose has been pushed into cells by the insulin? I'm confused. Anyone? Jack Daw 16:36, 22 June 2006 (UTC)

Insulin is reponsible of making energy ot of glucose found it the body. This is why you inject it to yourself if you have that specific illness (do not know the exact english name of it). Please consult the Book : Human Anthology for more specific answers. The brakdown of Glucose to Co2 happens in the cells, by ensims, so this has nothing to do with insulin, except that it is needed for it to happen. Ensims NADP and NADPH (if I remember correctly, couse I have learned it more than 8 years ago and have not used this knowlage since then) are responsoble of turning sugar into energy wich your body uses.--Mike

Let's try another explanation. In healthy people insulin rises when there is plenty of glucose around, like when you are digesting a high-carbohydrate meal. Insulin serves as a signal for many types of cells, stimulating some processes and inhibiting others. In general the processes stimulated by insulin are those that consume and store excess glucose, while the processes that are inhibited are those (in the liver) that produce glucose and release it into the blood. Glycolysis is an example of a process that consumes glucose, transforming it into energy and into substrates for storage or further synthesis. The opposite of glycolysis is the process of glucose production, gluconeogenesis, which is inhibited by insulin. alteripse 00:11, 23 June 2006 (UTC)

Firstly the effect of insulin on the rate of glycolysis (specifically phosphofructokinase(PFK) activity, PFK being the rate limiting step of glycolysis ) is independent of the effect on Glucose uptake by cells that insulin has. While insulin stimulates the breakdown of Glucose (Glycolysis) it does not stimulate the Krebs Cycle, this leaves the breakdown products of Glucose - in the form of Acyl-CoA, an intermediate which can then go on to be used in the synthesis of lipids, so if as alteripse suggested you view the actions of insulin as being to promote processes which consume glucose then you can see that all the effects of insulin are in fact pulling in the same direction.

Data Flow Diagram

Question number1:

                 What is the dataflow diagram to prepare a library management software?

Please post all of your homework questions at the same time so we only have to respond once with DYOH. --Kainaw ^(talk) 17:34, 22 June 2006 (UTC)

jvc video tape

←→§hello, could someone please help with my question.Iam trying to find out when JVC first launched its SX E-30 video tape many thanks –—…°≈±−×÷Alan Fry--80.41.71.23 17:58, 22 June 2006 (UTC)

You could start by asking JVC, rather than us? --Dweller 18:27, 22 June 2006 (UTC)

US Experimental High Speed Recon Crafts

I have been given the VERIFIED information, that a US military Recon Fighter Called "Aurora" exists. It has a speed of around 8 MACHS and uses RAMJET engines. I would like to ask if you have any information on this plane developped by france and sold to the US for use (france is currenly updating it as AURORA-II, with estimated speeds of around 10-12 MACHs. Please be warned, that this information was very hard to acquire and took me a couple contacts to get. What I found otu, is that it probably has a triangle shape and all engines are housed on under the wing. I am also missing the technical study aircraft of the russians (made by Mig)wich had a stealthy design and was capable of lifting weapons in it's two bays, each holding an A-bomb or 2 Aphid Heat seeking missiles. Both programs were considered Black, so no public informations were published.

Your answer can be posted to (blanked for privacy), due to the fact, that my other email addresses are probably being monitored.

Yours sincerely: (blanked for privacy).

Have you considered seeing what has already been written by people here at Aurora aircraft? --Kainaw ^(talk) 19:25, 22 June 2006 (UTC)

As it says at the top of the page, Wikipedia content is distributed widely on the internet, and putting your e-mail address here makes it very public. If you are concerned about your e-mail addresses being known, posting them on Wikipedia was probably not the best move.--Tachikoma 19:37, 22 June 2006 (UTC)

Browsing v Downloading

Forgive my ignorance of all things IT, but quite simply, is there a difference between Browsing and Downloading, or are they one and the same thing? Answers in non-techy speak please.

If you want to be anal, to browse something, you must download it first. Even if you are using remote browsing (ie: Remote Desktop), you have to download the image of what you are browsing locally. But, in common terms, browsing means you are just looking. Downloading means you are saving a copy for future use. --Kainaw ^(talk) 19:28, 22 June 2006 (UTC)

Thanks Kainaw, that's most helpful - but I will pass on the anal methinks.

Even some politicians don't seem to know this. In Dutch politics, there was a proposal to make the downloading of information that could be used for terrorist purposes illegal. The problem is, if you follow a link to a page that holds such info, you've already downloaded it. So you have to download the info before you can tell it's something 'illegal' (unless it's marked as such). DirkvdM 09:04, 23 June 2006 (UTC)

OK DirkvdM, to pursue your point: if a Dutchman innocently clicks on any link, and another webpage opens on his screen (whether legal or illegal), has he in fact downloaded it such that it will always be retrievable from his hard drive, even though he did not save it as per Kainaw's earlier explanation?

That depends on the web browser. 99.999999999% of the time, the answer is 'yes'. The page is stored in a "temporary" location on the harddrive and can be viewed later directly from the drive. I quoted "temporary" because web browsers tend to keep the files for a very long time. I've worked on people's computers that have "temporary" files that are over a month old. --Kainaw ^(talk) 16:31, 23 June 2006 (UTC)

OK and thanks. But what does our innocent but now worried Dutchman do after he has innocently clicked on the link and finds himself reading a notice from the Dutch Government that he has broken the law by doing so. Can he eliminate all evidence of his "crime", or does he destroy his hard drive, before they come knocking on his door to arrest him for his so called illegal activities?

All popular browsers have a way to delete temporary files. It is different for every browser. Usually, it is in settings or tools or something similar. --Kainaw ^(talk) 16:55, 23 June 2006 (UTC)

Thanks again. I was getting really worried about our poor Dutchman. I can now relax and let him concentrate on watching his national team win in their game next week against Portugal.

Thanks for rooting for us, but our innocent Dutchman is still not out of trouble. Deleting a file just makes the disk space available for future use. Unless the data is actually overwritten by other data, the info will still be there. You won't find it through normal ways, but there are ways to retrieve it. DirkvdM 18:15, 23 June 2006 (UTC)

Oh Dear. So he's back to destroying his hard drive then, before he can settle down to enjoy the match? And the lesson for the rest of humanity is to buy a crystal ball so that you can predict what is beyond the weblink you are about to click to ensure it doesn't contain anything illegal?

Actually, the trick is to avoid actions that would put you under suspicion to begin with. Is there one single example of a person who was investigated and arrested for visiting a website and doing absolutely nothing else that was illegal? There was a case shortly after 9/11 of a man (Nichols - forget his first name) who was arrested (and plead guilty) on something like 111 counts of child pornography. Nutjobs claimed he was arrested for looking at naked women that he didn't realize were underage. The truth: He was turned in by his mother for sexual assault of a little girl (6 or 7 years old - I don't remember). Police went to his house to investigate and found file cabinets full of photos of children, indexed by the sex act they were performing. After arresting him, it was discovered that the Feds were investigating him for online trade of child pornography. How this became a case of "an innocent guy who was abused by the system" completely escapes me. --Kainaw ^(talk) 23:48, 23 June 2006 (UTC)

Well, the thing is that that is exactly what was proposed in the Netherlands, to make the mere download illegal. The whole world is going apeshit and I'm surprised to find the Netherlands so much at the forefront of it (then again we've got the most right-wing coalition in ages at the moment). Innocent children in jail, people burned alive in a make-shift prison and mass extradition of immigrants (except when it's a party member of course). DirkvdM 06:27, 24 June 2006 (UTC)

Untitled Windows XP Install Issue

-Added heading to this question -Benbread 21:32, 22 June 2006 (UTC)

hi im trying to install a copy of wondows xp on ly laptop, but the instalation prosess ceeps going round in a loop, as it formats the hard drive then it copies files ot it, then it reebots and then so on in that sequence and i dont knwo what to do there is nothign in the instructions to help me. and i dont understand y it is doing this. (ps there is no former operating systm on the laptop as that was some hoe wiped form the hard drive and the recovery disks for some reason dont work) what should i do to install XP?

When the computer reboots do you press the key it prompts you to press, and if so don't. I always found that to be a stupid thing that seemed to confuse a lot of people. -Benbread 21:56, 22 June 2006 (UTC)

Teaching myself anatomy

I want to teach myself anatomy, to a doctor's level, profound knowledge. Would you recommend me any sources or good books? Thanks.

• Start here. Memorize every page. There will be a test. --jpgordon∇∆∇∆ 22:39, 22 June 2006 (UTC)
  • Seriously, all? Gaah! Jack Daw 23:04, 22 June 2006 (UTC)
    • Well, you did say "to a doctor's level"... -- Миборовский 07:57, 23 June 2006 (UTC)
• I'll echo Jpgordon's comment and say that Gray's Anatomy is the unquestioned gold standard for anatomical reference texts. From the standpoint of actually learning the anatomy, you could try visiting your local medical school's bookstore and pick up some anatomical colouring books. (Forcing yourself to identify and colour every bit of the anatomy is one of many pedagogical tactics to aid memory.) Practice always helps—for every part of your body that you can see and reach, try to identify all the visible or tacticle bones, muscles, tendons, blood vessels, etc. It's even more fun if you can find a friend who will let you play doctor. :D TenOfAllTrades(talk) 23:00, 22 June 2006 (UTC)
• Video! Anatomy for Beginners. Before you read anything, it's best to have a visual understanding of what's inside the body. It's utterly fascinating. --mboverload@ 23:04, 22 June 2006 (UTC)

I would recommend the Anatomy Coloring book very strongly (ISBN 0805350861), the Physiology Coloring Book is great too.Tuckerekcut 01:21, 23 June 2006 (UTC)

You could try vivisection on yourself. Several mirrors and loads of sedatives are recommended for this method. DirkvdM 18:18, 23 June 2006 (UTC)

And industrial cleaning supplies. --Ginkgo100 ^{talk · contribs} 21:48, 23 June 2006 (UTC)

Thank you very much for the very informative and humorous comments  ;)

human diagram - showings measurements of age groups

Been searching 2 days for a really basic, HUMAN BODY DIAGRAM - showing measurements of body divisions. (as, theigh portion of leg.) Measurements divided into 3 major age groups, (child, teen, & adult)-

Thanks, Boswell --Boswell6 23:15, 22 June 2006 (UTC)

Is this what you wanted? [12] alteripse 23:54, 22 June 2006 (UTC)

June 23

Name of a Phobia?

Someone I know is scared of wrists. Not that she constantly fears them or anything, she just doesn't like looking at them. She'll be fine as soon as she stops looking at a wrist so it's not like it really affects her in a huge way. However, everytime you show her a wrist, she'll cover her face with her arms and whimper. She wears short sleeved shirts quite often and says she avoids looking at her own wrists completely as well. Is this even a phobia and if it is, is there a name for it? --71.235.83.132

According to our article Greek and Latin roots, carp- is either Latin or Greek for wrist. It's probably Latin. In that case it wouldn't work because the suffix -phobia is Greek. In any case, carpophobia would most likely work because there are a lot of phobias that mix Greek and Latin roots. I don't know for sure though. schyler 01:52, 23 June 2006 (UTC)

please see or write the article wrist cutting. 82.131.184.195 01:52, 23 June 2006 (UTC)

On this page there are messages from a number of people who fear wrists. (May not display entirely in Firefox; IE is ok.) -R. S. Shaw 06:42, 23 June 2006 (UTC)

Every person's phobia doesn't have to have some silly Greco-Latin name. What your friend is experiencing is a specific phobia, and what it happens to be attached to is probably not that significant.--Pharos 07:11, 23 June 2006 (UTC)

percolated coffee

Why does percolated coffee loose its aroma and flavor after the first cycle of percolation? ...IMHO (Talk) 01:55, 23 June 2006 (UTC)

I believe that a lot of the flavor in coffee comes from certain volatile oils that are released when you heat the coffee. Since the percolation process is in effect cooking the coffee over and over, more and more of those oils evaporate into the air instead of remaining in the liquid.--Tachikoma 05:05, 23 June 2006 (UTC)

I thought the oils broke down during percolation, but it may be that they evaporate. — The Mac Davis] ⌇☢ ญƛ. 21:16, 23 June 2006 (UTC)

Why doesn't this happen when roasting? ...IMHO (Talk) 23:32, 23 June 2006 (UTC)

The oils might break down too, I forget--this was from a book on coffee I read a long time ago. In any case, I don't recommend percolation as a way to make coffee.

I assume that only whole beans would be roasted, so maybe the exterior of the bean is impermeable enough to keep the flavor in, at least for a while.--Tachikoma 23:41, 23 June 2006 (UTC)

mesh-ups

What is a mesh-up?

I am asking in the context of the related term called "Mashing". The term mash-up is borrowed from the world of music, where it refers to the unauthorised combination of the vocal from one song with the musical backing of another, usually from a completely different genre. Web mash-ups do the same sort of thing, combining websites to produce useful hybrid sites and illustrating the internet's underlying philosophy: that open standards allow and promote unexpected forms of innovation.

Apparently, this is actually a manifestation of MESHING, of finding bridge points between disparate pieces to make a new "sense" of something. In fact, this might be a very early community indicator, as mash/meshes point out areas of shared interest.

NOTE: there is also another meaning of "mesh-up" in the computer world of 3-D imaging. It is the term that describes the creation of 3-D shapes which are "meshed-up" into an interactive plane. This is not to be confused in our context!

So I am not sure that this is accurate and cant find information other than perhaps a book on the subject called: "Web 2.0: Web Services Mesh-up" by Alexander Peter.

Can you clarify this subject area?

breaking down .rar file into little parts

I've often seen this done (especially on torrents) but never been able to find out how to do it myself. Say I have a .rar file 2 GB large and want it to be broken into little files of 10 MB each. What programs can do it? -- Миборовский 08:00, 23 June 2006 (UTC)

If you have WinRAR installed then, unpack the RAR rile, now right-click on the file or directory you want to split and select the Add to archive... option, a dialogue box will pop up and the quickest way to split the file is edit the option in the bottom right corner that indicated "Split to volumes, bytes". Since you want 10MB files then fill in 10000000. You may also want to play around with the archiving options (specifically create solid archive, put authenticity verification, and put recovery record).--69.171.123.148 08:31, 23 June 2006 (UTC)

Memory

Does a full hard-drive weigh more than an empty hard drive?

Careful reading of the hard disk article would suggest not. Rockpocket 08:17, 23 June 2006 (UTC)

No, a "full" harddrive merely has all of its mini-magnets rearranged by the write head into patterns recognisable by the read head. AFAIK. -- Миборовский 08:19, 23 June 2006 (UTC)

However, if you save your word documents in smaller fonts and increase the font size only when you open them, that might save some weight. – b_jonas 08:55, 23 June 2006 (UTC)

I don't think this is true, because hard drives don't contain paper. They're already miniature sized representations. Is b_jonas just trying to mislead you?

I really must remember not to read the reference desk while drinking coffee. There's a high risk of drowning. Grutness...wha? 09:32, 23 June 2006 (UTC)

Certainly not, writing to a hard drive just rearranges existing magnetized particles, it doesn't add any mass (where would it come from?) EAi 10:12, 23 June 2006 (UTC)

It depends on how you define "full" and "empty". First, if you mean full or empty relating to meaningful information, then there is no mass difference since the orientation of a dipole does not affect the atomic mass of its composing particles. (Or does it? I'll have to doublecheck this assumption.) Second, say that by empty you mean demagnetized (that is, the same material exactly but not magnetized or magnetizable) vs a full (that is, a magnetized one), then the masses have to be different, because some of the electrons will occupy different atomic orbits (different energy levels), thus will have very slightly different mass.--JLdesAlpins 14:49, 23 June 2006 (UTC)

I was just thinking about whether a charged capacitor weighs more (on an electron mass scale), but I don't think so, since more electrons on one plate means less on the other. I wonder if any electronic (computer) component experiences a change of mass. --Zeizmic 12:18, 23 June 2006 (UTC)

Would a USB flash disk, with all the tunneling of electrons? I haven't looked at the article to see a detailed description, so this is just a guess. --80.229.152.246 15:58, 23 June 2006 (UTC)

Guessing, a new one would weight less, although even if it was wiped and empty, if it was used, it still has the electrons in it all set to whatever 0 or 1 positions your wiping software did. — The Mac Davis] ⌇☢ ญƛ. 21:18, 23 June 2006 (UTC)

A charged capacitor has an electric field between its plates; this field has energy and therefore mass. The energy in a capacitor is $CV^{2}/2$; typical values for a computer-type application are $C=1\mu F$ and $V=5V$, giving $E=1.25\times 10^{-5}J=1.53\times 10^{8}m_{e}c^{2}$. So the energy stored in a capacitor can easily have mass equal to that of millions of electrons. But remember that the capacitor will have many more electrons than that: a gram of iron contains $2.80\times 10^{23}$ electrons! --Tardis 02:13, 24 June 2006 (UTC)

Given that a computer is a modelisation of our own thinking processes : When we learn something, whe should gain weight. --DLL 10:12, 24 June 2006 (UTC)

Why don't ships sink?

Paddling a canoe the weigh of the paddler is spread over a large area. Given the weigh of a large ship, for example aircraft carrier of oil tanker, and the small area in the water, why doesn't it sink?

Einstein's Shadow

--Einstein's shadow 10:03, 23 June 2006 (UTC)

Due to Buoyancy. The water surrounding a boat exerts a force on it. The angled sides of the boat channel this force upwards, i.e. pushing the boat out of the water. As soon as the entire boat is under water, an equal force is exerted on all sides (i.e. there's water on top of it) and the boat sinks (well, actually the force is marginally higher at the bottom due to the fact that the pressure of a liquid increases as the depth increases, but gravity outweighs this). EAi 10:11, 23 June 2006 (UTC)

From what I remember of buoyancy, the shape of the boat isn't really relevant to whether it sinks or floats, is it? Buoyancy helps you decide whether things float, and how high in the water they would be, but really it's as simple as this: things that are heavier than water (like stones) sink; things that are lighter than water (like wood) float. Big ships have a lot of metal, but they also have a lot of air inside, and it is this that makes them, overall, lighter than the water. ("Lighter than water" is shorthand for "having a lower density than water"). Of course, if a ship is badly designed so that water can get in and replace the air, it will probably sink. To return to terms in the original question: the area is not important, but the volume is critical. Notinasnaid 10:52, 23 June 2006 (UTC)

Shape sure does make a difference - if a boat capsizes, the air will leak out (to be replaced with water), and the boat will sink. If the ship were hermetically sealed, the shape would not make a difference as the average buoyancy would be unchanging, but in the real world (other than a submarine) that's not how it works. Raul654 11:54, 23 June 2006 (UTC)

I think we're just agreeing with each other, but let's try to be clear: the shape itself doesn't dictate whether an object floats, but of course if the shape is badly thought out the boat may capsize, and if the boat is badly designed a capsized boat will leak, so it will replace air by water and it will sink. However, I don't think it makes any difference to buoyancy whether the area below the water is slope edged or square box or anything else, except in as much as this shifts the centre of gravity and affects how much can be above the waterline and remain stable; and some shapes are better for moving through water (which isn't the issue). Notinasnaid 12:01, 23 June 2006 (UTC)

You may have a look at the wiki article - waterline...

Pupunwiki 12:08, 23 June 2006 (UTC)

Shape will determine how it floats - what level the water rises to, and which direction points up.... Nimur 19:46, 23 June 2006 (UTC)

Because a ship weighs less than the water it displaces? Obviously! remeber a cubic metre of water weighs a tonne, its not light stuff. And with all that air on board, its bound to be lighter. Philc _T^E_C^I 21:35, 23 June 2006 (UTC)

Thanks for answering my question........so is it yes? or no?

er.. the intial question isn't a yes/no question. Philc _T^E_C^I 01:33, 24 June 2006 (UTC)

A QUESTION ABOUT C PROGRAMMING.

Hello, I was recently reading a book "Structured C Programming" by some author. In it he has mentioned one code which i am not able to understand. It goes as follows :

printf("%d %8.2f %d %hn",i,x,j,&count);

He says that : " If you need to verify the number of input or output characters, you can do so by specifying the n code. This code requires a matching variable address into which scanf or printf places the count of the characters input or output. If the code is prefaced with an h, the matching variable must be short; if it is l, the variable must be long. Since the operation places the results in the variable, its address must be used in the parameter list. In the following example, "count" is a short integer that is to receive the number of characters written".

And then he mentions the forthmentioned code.

My question is that what is the variable count doing? And if I want to see the value of this variable "count", how should I get it printed, because I tried the usual way : printf("%d",count), but it didnt work ! Then I tried to print it using the "%hn" specifier as mentioned by the author, but it also didnt work !

So some help is needed. Thank You.

Perhaps a programming website would be more suitable for such a question? Theres many of them. See [13] for documentation on printf. This code:

short count = 0;
int i = 1, x = 2, j = 3;
printf ( "%d %8.2f %d %hn", i, x, j, &count );

Would store the value '3' in count as three values: i, x and j have been outputted so far. I've never used or seen this functionality and can't see much reason to.

%hn means: output the number of variables written so far to the short specified. The h indicates that the argument is a short, not (as assumed by default) a long. Hence, the variable count in the example above is defined as short. Read that linked documentation for more info. EAi 11:01, 23 June 2006 (UTC)

printf("%d",count) should be fine, provided count has a suitable type. For instance if you've used int count. If count is another type (like long or double) you need to use a suitable, different, format string. Indeed you should spend some time looking at the specification of printf strings, though it can be pretty confusing; if you are just starting out, maybe stick to some recipes for the types you use, and come back to learn format strings later. (Even as a C programmer for over 10 years, I still have to go back to check the rules for printf sometimes). Notinasnaid 11:53, 23 June 2006 (UTC)

Well, its going to be a short, not an int as its %hn :) EAi 12:01, 23 June 2006 (UTC)

Human genetic variation by continent

Not too long ago, I was confronted with the following multiple choice question in an exam (freely translated):

The human population of which continent shows the highest degree of genetic variation?

1. Europe
2. Africa
3. North America
4. Asia
5. South America

Now, the correct answer according to them is Africa. I answered it right by feeling, but I still thought it can't really be true. I mean, even with the "out of Africa" hypothesis, which would mean that modern humans in Africa had the most time to evolve etc., there are people of African origin in all parts of the world. So my natural feeling was that Northern America, with its most recent, but most mixed population should have the highest degree of genetic variation. Is Africa the correct answer? Would Africa only be the correct answer if the question would be: "The native/original human population ..."? Is the question just plain dumb and not clearly answerable? Thanks, -- Totti (talk) 11:37, 23 June 2006 (UTC)

Have a read of this article (about a quarter of the way down it mentions this specifically). It doesn't make it seem as cut-and-dry as the question suggests. You could also see table 2 on page 3 of this document - it gets pretty technical, but you could probably find some help there. This article is also very accessible and could be interesting to you. EAi 11:48, 23 June 2006 (UTC)

Thank you, although not really answering my question (which I expected), those links were very useful. -- Totti (talk) 14:10, 23 June 2006 (UTC)

The answer is correct based on all of the population genetics research of the last 4 decades. The question requires a relatively sophisticated understanding of human population genetics. As you mention, most people would assume that the population of North America has the greatest diversity, which might be true if the question were posed as "which continent shows the greatest degree of diversity of geographical location of 3 century ancestors?" The gene polymorphisms responsible for the most obvious outward differences of human skin and face shapes are fewer and less ancient and fundamental than a variety of other less visible polymorphisms present in the African population. Nearly all of the populations of the other continents share many of these genes with one subset of the African population. I assume this was a higher-level exam? alteripse 13:08, 23 June 2006 (UTC)

Yeah, I do have advanced understanding of population genetics, and I knew about most of that (visible vs. hidden polymorphisms), but I just thought the question itself was biased, because as I said, due to migration, I'm pretty sure no one can clearly say what continent has, at the given time being now, the highest amount of genetic diversity. Of course I both agree and would naturally assume (and also it's undoubted because of research), that the original population of Africa would match this criteria. Or do you mean that despite migration, Africa still has a larger gene pool (e.g. more Africans would have to emmigrate to reduce Africa's gene pool or expand other continent's gene pools enough)? It's a question from my finals (second semester, medicine, Medical University of Vienna), and in my opinion a bad one. -- Totti (talk) 14:10, 23 June 2006 (UTC)

I don't know from genetics. But the blacks in blacks in Africa that descend from slaves are of the Bantu variety. But in Africa there are also nilotic people in the East, who are a completely different 'race' (insofar as there are human races), more closely realted to semites, I believe (actually, they look like whites, except that their skin is black. And there are also pygmees in the centre and bushmen in the south. And especially these last two groups you won't likely find elsewhere. But 'races' from other parts of the Earth are found in Africa, namely whites and Asians. No Indians, though, I suppose (American Indians, I mean). But I suppose the nilotic people, pygmees and bushmen tip the balance. DirkvdM 18:44, 23 June 2006 (UTC)

The answer is correct, and is consistent with the Out-of-Africa theory of human migration. Non-Africans are genetically more related to each other than they are to Africans because they are all descended from a small group of humans that migrated out of Africa. - Cybergoth 22:14, 23 June 2006 (UTC)

If one person from "one end of the human gene" born in Africa moved to South America, and a person from the "opposite end of the human gene" born in Africa moved to South America too, wouldn't the contrast between only those two people qualify SA as the continent with the highest amount of genetic variation? Or would that only count as genetic range? I find it difficult to accept such a simple answer to the multiple choice question.  freshofftheufoΓΛĿЌ  12:21, 24 June 2006 (UTC)

Dream

Sometimes I dream I stumble and fall and during that I shudder in bed. Is it because of the fall of the muscular tone? --Brand спойт 12:11, 23 June 2006 (UTC)

Since you are interested, this is a great opportunity to look up sleep and dreaming in this encyclopedia. You will find that when you dream, the brain turns off its ability to control muscles. However, this is not perfect, and some 'leakage' occurs. If you watch a dog dream, you can see that their 'switch' is not that good. --Zeizmic 12:24, 23 June 2006 (UTC)

And lets not even start about sleepwalkers...

You have possibley fallen victom to the Hypnic jerk, which more interestingly happens to teenagers at night than say, adults, or younger kids. Otherwise, its just a Myoclonic twitch. If you actually made it to the full dreaming stage, and drempt you fell, and woke up because of your unconcious body moving around, that came from (I forget) some kind of falling-from-the-tree-impulse, because we used to sleep in trees. If we started falling, the impulse would make us immediatley wake up and already have our limbs moving out to try and grab a branch or at least break our fall with a lmib instead of a head. The only times I wake up from deep sleep this way are when I am actually falling off the side of the bed. It is amazing to me that I can wake up and pull myself back up before I hit the ground. Guess its working!! — The Mac Davis] ⌇☢ ญƛ. 21:23, 23 June 2006 (UTC)

Odysseus build his bed in an old olive tree and his house around. His wife recognizes him when he hints at that. --DLL 10:07, 24 June 2006 (UTC)

Referrence

Can you exolain me and give refference to me on destructive distillation of wood?With pictures.--Saksham Sharma 12:58, 23 June 2006 (UTC)

You already asked this question and it was answered: Wikipedia:Reference desk/Science#Environmental Question. — QuantumEleven 13:16, 23 June 2006 (UTC)

ocean currents

Please tell me about ocean currents in full detail.Please give me the referrence also.--Saksham Sharma 13:05, 23 June 2006 (UTC)

There is a very nice little box on the left side of your screen, labelled "search". Type in "ocean current". Hit "Go". It will take you to our article on ocean currents, where you should find anything you need to know. The article even has some external links for further information if you need more. — QuantumEleven 13:08, 23 June 2006 (UTC)

Also note that just saying "please" at the beginning of every question doesn't necessarily make them polite. The requests have to be reasonable and you have to say please for the question to sound polite.  freshofftheufoΓΛĿЌ  12:14, 24 June 2006 (UTC)

Glycol-modified PET

I'm looking for the chemical structure of a plastic, but all my web searches have been fruitless. The plastic in question is PETG (Glycol-modified PET). Wikipedia has a nice article on PET, but not PETG. Can sombody help me figure out where the glycol modifications are on this molecule? Many thanks. - M

I was having lots of fun looking up 'petg' and 'chemical structure petg' on Google, but then I discovered that this was a standard university homework assignment. --Zeizmic 17:13, 23 June 2006 (UTC)

Not, not homework: my lab is growing endothelial cells on PETG disks, and we want to modify the plastic so as to be more hydrophilic. I was hoping somebody would know exactly how glycol-modified PET is glycol-modified so that we can figure out whether it's worth it. - M

Chemical structure of polyethylene terephthalate

PET is poly(ethylene terephthalate) while PETG is poly(ethylene terephthalate) glycol. The only difference between the two is that PET has a hydrogen at one end and a hydroxyl at the other, while PETG is a glycol, with two terminal hydroxyls. – ClockworkSoul 19:06, 23 June 2006 (UTC)

IAU and the naming of satellites

Inspired by the recent naming of Nix and Hydra (moons of Pluto), I have a couple of questions about the formalities of satellite-naming:

1. When the IAU officially accepts a name for a satellite, what form does the official announcement take? Is it always in an IAU Circular?
2. Does the IAU have several official languages in which it makes such announcements, like the UN? Or are the announcements only made in English?

Thanks, Cam 14:57, 23 June 2006 (UTC)

entomogamy

I've been translating Clematis vitalba from the French article, and there is a word "entomogame", which it appears means something like "transferring seeds by the wind". I guessed the English translation would be entomogamy or something similar. Does Wikipedia have an article on this, or something the same? I assume we would anyway. --Brandnewuser 15:44, 23 June 2006 (UTC)

No, not by the winds, by insects. See the related word entomology. The -gamy bit relates to reproduction (i.e. here pollination), see the related word gamete. Arbitrary username 16:31, 23 June 2006 (UTC)

It turns out that entomophily is the actual term. But entomogamy seems to be listed elsewhere, so I'll create a redirect. Arbitrary username 16:33, 23 June 2006 (UTC)

Good work. How about the phrase "méso à eutrophiles", which was listed under the "habitats" section? --Brandnewuser 23:23, 23 June 2006 (UTC)

Méso is greek for middle - medium habitat I'd guess. eutrophile indicates a living form that loves good food : like some water plants where there's plenty of nitrates dissolved. --DLL 10:02, 24 June 2006 (UTC)

Sugar Granule Size - Does It Really Matter?

If it's going to get disolved in water, what possible difference does it make, whether I use caster sugar or icing sugar? Why not just granulated sugar? When it's dissolved, it's just sugar water, no matter what size the granules were to begin with? http://www.supercook.co.uk/inspiration/recipe-ideas/details/12011 --Username132 (talk) 17:21, 23 June 2006 (UTC)

Dissolving is a reaction that occurs on the surface. The smaller the sugar granules the more surface for a given amount of sugar (assuming the sugar is the same thing except for granule size obviously), so the faster it will dissolve. DMacks 17:41, 23 June 2006 (UTC)

Yeah, so it takes five minutes longer - big deal - at the end of it, you're left with the same solution, right? --Username132 (talk) 18:08, 23 June 2006 (UTC)

Perhaps a given volume of caster sugar is slightly more dense than the same volume of granulated sugar, thus you'd get a sweeter syrup using the former. Given the recipe you linked, you probably won't care after consuming one or two of those jellies. --LarryMac 18:18, 23 June 2006 (UTC)

If you're disolving it in water, you're right. The reason for the variety is that the texture of the granuals and their speed of entering solution matter for some cooking. Trollderella 18:21, 23 June 2006 (UTC)

According to the sugar article, in powder sugar, "The manufacturer may add a small amount of anti-caking agent to prevent clumping". DirkvdM 18:53, 23 June 2006 (UTC)

Also keep in mind that the actual shape and size of sugar is sometimes used. For example, when making cookies you start by creaming butter by adding sugar and mixing it so that the sugar crystals basically slice up the butter and introduce small pockets of air. Using a finer sugar would create smaller pockets of air and so the resulting texture would be different. There may also be times when you want to form a sort of colloid of sugar and fat, in which case the size of the sugar particles would affect the texture of the mixture (e.g. in frosting/icing). 128.197.81.181 21:41, 23 June 2006 (UTC)

When dealing with ingredients such as sugar and salt, it's important to use the same grade as the recipe calls for if the recipe amounts are volumetric (as they almost always are). Finer particles will result in adding too much of the substance and coarser ones in adding too little. Flour is so variable in density that I've seen recipes that specify a weight of flour rather than a volume. 128.197.81.181's comments are also important if the sugar is not to be dissolved. --Ginkgo100 ^{talk · contribs} 21:59, 23 June 2006 (UTC)

photosynthesis and cellular respiration

Okay i have two questions that are tied in with each other.

1a. How would the composition of earth's atmosphere change if green plants and other autotrophs disappeared?

1b. How would animal life be affected by this atmospheric change?

Any help with these questions would really be appreciated. I've looked all over and can't find answers. I don't remember anything like this being in the book, and i homeschool so there is no teacher for me to ask.

Hopless Biology Student

Your best bet is to research photosynthesis, autotrophism, and atmosphere - I think you'll see quickly that green plants contribute to the various gas cycles, release and absorb Oxygen and Carbon Dioxide, participate in the Carbon cycle, Nitrogen cycle, and probably absorb considerable solar radiation that would otherwise become heat. I imagine your questions should be answered in essay form, so you might want to do some thorough reading in your textbook as well. Nimur 19:54, 23 June 2006 (UTC)

C'mon man, read the textbook first next time!! You may not be able to copy a sentance verbetium, but you will learn the answer rather than relying on us to tell you. — The Mac Davis] ญƛ. 21:43, 23 June 2006 (UTC)

Thank you for letting me know what to look up... i kinda get it all now... thanks  :)

Macbook Pro // Bootcamp

Okay, I want to get a Macbook Pro for my next school year. But I also want to have Windows on there.

My question is this: Boot Camp is currently in beta, but it'll be official when OS X 10.5 comes out in late November I believe. However, I will need to have a laptop before August. Is it likely that Apple will release Bootcamp Final for all the saps who bought a new computer for the new school year with 10.4? — Ilyanep (Talk) 20:04, 23 June 2006 (UTC)

Well, no one can tell you that without resorting to tea leaves or tarot cards. But even as beta, Boot Camp seems quite well-behaved and problem-free. So I wouldn't wait for Bootcamp Final, as it will mostly be a name change. But if beta vs final is important, and even if not, I would consider using Parallels Desktop for Mac virtualization software [14] instead of Boot Camp, as you can run MacOS & Windows simultaneously (Windows running in a window in the Mac OS), and cut and paste between them, rather than rebooting and running only one at a time as Boot Camp requires. [15] - Nunh-huh 20:26, 23 June 2006 (UTC)

But I probably want to have full performance for gaming. Also, the difference between beta and final may be pretty big considering what Apple tends to do. On the other hand, the way it works now is probably enough for me. — Ilyanep (Talk) 20:47, 23 June 2006 (UTC)

How good is Bootcamp? I thought that Windows would be noticeably slower. I predict OS X 10.5 to come out later this year (oh, you said that), and it will have Bootcamp bundled in a final release. — The Mac Davis] ⌇☢ ญƛ. 21:14, 23 June 2006 (UTC)

I hear that a Mac running Boot Camp and Windows XP is almost as good and even better than some high-end PCs running Windows XP. — Ilyanep (Talk) 22:33, 23 June 2006 (UTC)

There are ways to just install both, and choose as it boots which you run. Though I cant remeber how, thoguh some clever guy programmed the choice to a tilt swith, so it booted linux one way up, and woindows the other. I'm sure a similar thing can be done with OSX and windows. though a tilt swith would be innapropriate in a laptop! Philc _T^E_C^I 21:24, 23 June 2006 (UTC)

Types of melting

i was tolt that there are two types of melting, one is called a "pasteous melting" and the other one is "frank melting", physics consider some objects like parafin and glass as liquids and when heat is added to them, they melt not like the water ice cubes, they do it slowly and they call it pasteous melting. I have found this right here -> in spanish on page one, but i am still confused on the meaning of both types of melting. What a "pasteous melting" and "frank melting" are ?--HappyApple 22:07, 23 June 2006 (UTC)

I'm not familiar with those terms, but some materials, like water ice, melt all at one temperature, while others, like glass, slowly transition from an apparent solid to a thick liquid to a thin liquid as the temp increases. StuRat 03:45, 24 June 2006 (UTC)

Optical propreties of the human eye

If you had to compare the human eye to a camera lens and sensor, how would you describe the ISO range, aperture range and focal length? --Jcmaco 22:26, 23 June 2006 (UTC)

F-number says "the f-number of the human eye varies from about f/8.3 in a very brightly lit place to about f/2.1 in the dark". The eye doesn't really have a focal length, because it's the shape of the lens that changes, not the distance from the lens to the retina. I have good eyes and I can focus from infinity to about 15 cm. —Keenan Pepper 22:49, 23 June 2006 (UTC)

ISO corresponds to adaptation to light intensity (such as night vision) and aperture is determined by the iris. The focal length is indeed fixed. I suppose this is possible because the retina is essentially part of the brain and therefore able to interpret the 'blurry image'. Though I'm not sure how that would work. DirkvdM 06:37, 24 June 2006 (UTC)

steriliziing an Ace bandage

I wish to know whether there is a way to sterilize an Ace bandage [redlink, needs writing] without ruining it. I have an Ace bandage that has possibly MRSA-infected bodily fluids on it.—msh210℠ 22:54, 23 June 2006 (UTC)

I see Sterilization (microbiology)#Chemical sterilization, which has some information, but I need a household-available sterilizing agent, and need to know that it won't ruin the Ace bandage. Any help would therefore be appreciated.—msh210℠ 23:09, 23 June 2006 (UTC)

Why not just get a new Ace bandage and dispose of the infected one? What makes this particular one so important? M@$+@ Ju ~ ♠ 00:36, 24 June 2006 (UTC)

Can an Ace bandage survive high temperatures? Baking it at 350F for a few hours should kill anything. Alternatively, if you've got a pressure cooker, you could try using it as an autoclave. --67.185.172.158 04:55, 24 June 2006 (UTC)

Solquid

What is the technical/formal term for a substance that is neither solid nor liquid, but somewhere in-between? Yogurt is the best example I can think of at the moment, or perhaps a thick milkshake. --71.98.5.11 23:11, 23 June 2006 (UTC)

Custard is a Non-Newtonian fluid meaning its viscousity changes with strain, so with enough pressure applied, it can become solid. I think. Philc _T^E_C^I 23:18, 23 June 2006 (UTC)

It's either one or the other. However, you may be thinking of a suspension of solid particles in a liquid, which is known as a colloid. --Ginkgo100 ^{talk · contribs} 00:35, 24 June 2006 (UTC)

Yeah, this question was recently asked by User:Keenan_Pepper like last month. — The Mac Davis] ⌇☢ ญƛ. 03:12, 24 June 2006 (UTC)

My question was specifically about Frosties, in response to the "soquid" commercials. I think we concluded they were colloids, right? —Keenan Pepper 04:05, 24 June 2006 (UTC)

How about a plain old gel ? StuRat 03:34, 24 June 2006 (UTC)

Amorphous solids, like glass, also have characteristics of liquids (such as flowing over time), and are sometimes called "supercooled fluids". StuRat 03:40, 24 June 2006 (UTC)

There are classifications for everything... try this: Suspension (chemistry). I think that's where yogurt would fall. --Bmk 03:51, 24 June 2006 (UTC)

Yellow Water-lily

Does the word hydrochore or something that may look similar mean anything, maybe meaning something like "disperses seeds through water", in the dissemination of plants, specifically the Yellow Water-lily?

Sure, a hydrochore or a hydrochoric plant undergoes hydrochory, the dispersal of seeds by water. They're all legitimate English words. Maybe someone should start an article at Hydrochory. —Keenan Pepper 04:15, 24 June 2006 (UTC)

They all come from the Greek ὕδωρ, "water", and χωρειν, "spread". —Keenan Pepper 04:24, 24 June 2006 (UTC)

June 24

Help Me Identify This Butterfly

On my photographs page, I have added a picture of a butterfly that I took this morning. The picture was taken in New York City, and I'm interested in what it is. Thanks to anyone who can help! M@$+@ Ju ~ ♠ 00:54, 24 June 2006 (UTC)

That's a black swallowtail, resting on a purple coneflower (echinacea)--Mark Bornfeld DDS 03:03, 24 June 2006 (UTC)

Awesome! Thanks alot for your help :) M@$+@ Ju ~ ♠ 03:26, 24 June 2006 (UTC)

Ice cubes

Why do my ice cubes come out of their trays crushed sometimes and whole other times? --24.209.166.131 03:47, 24 June 2006 (UTC)

When water frees, it expands. This can result in ruptures in the cube, and can even cause a spike to form in the center. If the freezing happens from the bottom up, however, the water level will just rise and a nice cube will be formed. How the ice tray cubes are placed in the freezer, and how close they are to the cooling elements and other items, may affect the direction in which the cubes freeze. StuRat 03:52, 24 June 2006 (UTC)

Neuroprosthetics or Neuro cybernetics

I have checked both pages on Neuroprosthetics and Neuro cybernetics, but am I still not sure of the following.

I want a career in Neurology, but am not sure of the exact one. I want to be able to study making machines work with human and animal brains, and other parts of the central nervous system, such as virtual reality or machines that "alter" the mind in order to create a false reality. I have narrowed it down to either Neuroprosthetics or Neuro cybernetics, but I still can't figure out which one best fits that description. Can somebody please tell me which title, Neuroprosthetics, Neuro cybernetics, or something else best fits that description? Thank you.

Sincerely, --Dac011893 03:54, 24 June 2006 (UTC)

I would think the neuro-cybernetics would be closer to what you want. This might include things like the new process for implanting electrodes into the brain so blind people can "see" using a video camera. StuRat 04:10, 24 June 2006 (UTC)

Magnetic fields

I know that a moving electric current creates a magnetic field, but why?

Gooood question. I think the answer has something to do with tensors, something about how the electric and magnetic fields are really parts of one complex tensor field. I think it also has to do with special relativity, because if you're moving along with the charge then in your reference frame it's at rest, so there's no magnetic field, but if you're moving relative to it, then spacetime is all shifted so there is a magnetic field. Someone more advanced in physics than I should probably handle this one... —Keenan Pepper 04:35, 24 June 2006 (UTC)

Solid eggs

What's the freezing point of a chicken egg? Is there anything else that could cause an egg to solidify in a refrigerator? --67.185.172.158 04:46, 24 June 2006 (UTC)

Part 15 of the FCC rules.

Why is it so important that FCC rules require electrical devices to accept interference that may cause undesired interference? I'm a science teacher and when one of my students asked me this question, I had no clue. I've searched a bit, but the only explanations I have found pertain to causing inteference.

Here's the standard language found on many consumer electronics: This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any interference received, including interference that may cause undesired operation. User101010 05:14, 24 June 2006 (UTC)

Isn't this a linguistic thing? Doesn't "must accept" here mean "must be able to deal with"?

By the way, are you as generous to your pupils or do you only give yourself all tens? :) DirkvdM 06:50, 24 June 2006 (UTC)

Has anyone ever disproven this idea?

Is it possible that all identical isotopes have the same life span and were simply created at random times and therefore appear to have random life spans? Has anyone ever disproven that what many consider to be entirely random decay occurs instead at exactly the same interval from the moment the isotope was created? ...IMHO (Talk) 08:34, 24 June 2006 (UTC)

If your theory would be correct, I am quite sure that someone would have proven it already. Thus, most likely, it is not correct. --Andreas Rejbrand 08:55, 24 June 2006 (UTC)

Perhaps this explains why we find outselves living in a world in which only certain prized individuals are allowed to invent anything or at least to receive the credit. ...IMHO (Talk)

Routine neutron activation work rules out your idea. Dragons flight 09:34, 24 June 2006 (UTC)

Please explain how neutron activation would rule out a uniform interval between isotope creation and termination except by interuption of the interval. ...IMHO (Talk) 10:11, 24 June 2006 (UTC)

Nuclear waste takes tens of thousands of years to decay, if your theory were correct it would have taken tens of thousands of years to make, and it didn't. Thats an obvious example, but more obviously, all substances start to decay immediately, meaning some atoms have decayed in fractons of a second, which would mean that some process would have to bee continually making atoms to decay, if they decayed after one second, and the half life was longer. Philc _T^E_C^I 10:05, 24 June 2006 (UTC)

You have misunderstood the question. ...IMHO (Talk) 10:12, 24 June 2006 (UTC)

technology

i have heard that a student from electronics/electrical engineering can specialize in computer science laterbut not vice versa. how far is this true?

Cure for a phobia

Interested in the question above about that irrational fear towards wrists, I was wondering... Are there general cures for phobias? What is, generally speaking, the "method" they follow? Thanks.

Seagulls

Which is your favourite breed of seagull? I like the great black-backed gull the best. It's like having an albatross in your garden. Big, beautiful bird. --84.66.114.107 11:52, 24 June 2006 (UTC)

How do you judge the goodness of seagulls? I can't say I've ever had a good experience with a seagull before, people from 'round my parts tend to think of them as pests rather than magestic birds. Personally, I prefer the seagulls I saw in Toronto to the ones in Tokyo, but that's only because they look less menacing to me up close.  freshofftheufoΓΛĿЌ  11:58, 24 June 2006 (UTC)

Glasses

Can aesthetic glasses (no corrective lenses) cause eye strain? I've just started wearing glasses (though I've never needed them) and I'm wondering if this pain is just from the weight of the glasses on my nose or from staring into the (flat) lenses.  freshofftheufoΓΛĿЌ  11:58, 24 June 2006 (UTC)

It's kinda weird wearing glasses for aesthetic reasons.

Application Error

Quite often, but not always, when I close my newly installed Internet Explorer 7 Beta window, I get the error message below.

File:Application Error.png

If you are familiar with this problem, then I ask that you suggest a solution.
My operating system is Windows XP Media Center Edition.Patchouli 12:49, 24 June 2006 (UTC)