Wikipedia:Reference desk/Science

June 3

batteryless flashlights

could not find information on how batteryless flashlights work.do u have any info.on this? —The preceding unsigned comment was added by 66.174.93.98 (talk • contribs).

One method would be to generate electricity though mechanical action. A changing magnetic field (caused, say, by moving a magnet) creates a current (see Electrical generator). If the batteryless flashlight you're thinking of is one in which you pump a handle or crank to light it up, what you are likely doing is spinning a magnet around inside of a coil of wire. For more information on this, see Mechanically powered flashlight. Hope this helps. --TeaDrinker 07:58, 3 June 2007 (UTC)

The next step is to introduce a capacitor to store energy that can be released when you stop turning the dynamo. Otherwise the light goes off when you stop winding. Bendž|Ť 13:26, 3 June 2007 (UTC)

Some "batteryless" flashlights may acutally contain batteries which are charged by a hand crank generator or other mechanical means (I have one of these that really has a Lithium Ion battery inside). It is also possible that some of them don't use batteries, instead using a clockwork mechanism, perhaps storing energy in a spring (device) or flywheel, then releasign that energy into a generator which then powers the light. See Self-powered equipment and Batteryless radio. -- Diletante 15:41, 3 June 2007 (UTC)

I have one that you shake back and forth – it involves copper wire coil and presumably a magnet inside the coil. Vranak

I've just bought one that involves squeezing a lever (which I think operates a rachet, flywheel, and dynamo). I am disapointed with it: it is very noisy, it is too tiring to keep it going for long, the light is weak and intermittent. In my opinion, you are better off having a conventional torch - or flashlight in American English - plus some spare batteries. 80.0.100.234 08:27, 5 June 2007 (UTC)

plant's Water purification

It would be nice if there's links and reference: How plants can purify the solutions and water in the ground and attract necessary substances? how they can discern the particles of substances and elements , with what special characteristic of them? Is the attraction according to the requirement or instinctive?Flakture 04:58, 3 June 2007 (UTC)

Root#Root structure and osmosis are good places to start. Dr_Dima.

Sunrise Sunset Time Differences

Why is it that on June 17th the sunrise in NH is at 5:09 AM and sunset at 8:30 PM, but in FL the sunrise is ar 6:25 am and sunset at 8>24 PM. I can understand the sunrise time differences are due tot he curvature of the earth and would vary during the year, but I had expected the sunset times to also vary and be different. Dick: 209.247.23.5 10:49, 3 June 2007 (UTC)

New Hampshire is much further north than Florida, and therefore, the changing seasons have a much greater effect on day length - As it is currently summer in the Northern hemisphere, an NH day is almost an hour and a quarter longer. As we approach the summer solstice, the NH day will grow even longer compared to the Florida day, but in winter, Florida days would be much longer than Hew Hampshire days. The weather stations where sunrise and sunset are measured from are probably not on the same line of longitude; if they were, the difference between the two sunsets would be the same as the difference between the sunrises (in other words, it's just chance that the two sunsets occur at the same time). Laïka 11:06, 3 June 2007 (UTC)

Would point out that here in NH, the sun is closest to us in the winter, and furthest from us in the summer. I'm guessing that this is what is causing the unexpected sunrise/sunset differential, that the sun is physically closer to different parts of the world at different parts of the year. Maybe the Analemma is related. - MSTCrow 15:43, 3 June 2007 (UTC)

I'm not sure about the relative distance of the sun in winter or summer, but the important thing is that the axis of the earth stays at a tilt, like a gyroscope. As it goes around the sun during the year this means that one hemisphere or the other gets more or less sunshine, corresponding to summer or winter. Imagine light from a distant source falling upon a model globe with a tilted axis. One of the hemispheres will have more shadow than the other. 80.0.100.234 08:33, 5 June 2007 (UTC)

I assume by NH, you mean the Northern Hemisphere, not just New Hampshire. -- Diletante 15:52, 3 June 2007 (UTC)

It couldn't be the whole northern hemisphere - the sun is both rising and setting at every point in time simultaneously there! Laïka 16:50, 3 June 2007 (UTC)

Dick, see if you can find a map-tool that shows what parts of the world are in sunlight at a given time – ah, I see there's a link at terminator (solar). You'll notice that at (your) summer sunrise the terminator runs NW/SE, while at (your) summer sunset it runs SW/NE. Thus your example town in Florida can be near your sunset line but not near your sunrise line. Does that make sense? —Tamfang 01:48, 4 June 2007 (UTC)

Difference between Sagittal and Medial planes in human Anatomy

I am struggling to complete an assignment on the position and actions of muscles in the body as I can't seem to figure out the difference between the Sagittal and Medial Planes in the human body.

Having scoured the net, the information I have found seems to be at best unclear and at worst contradictory.

Please could someone clarify this for me?

Thanks Becks.

A mid sagital line is a medial line. However, not all sagital lines are mid-sagital therefore they are parallel and only very by a X intercept. 68.41.155.159 13:07, 3 June 2007 (UTC)

See Gray's anatomy online and this illustration. There is only one median plane. It divides the body into two roughly symmetrical halves. Any plane parallel to the median plane is a sagittal plane. Thus, the median plane is a sagittal plane (and is therefore also called the mid-sagittal plane). For an example of a sagittal plane that is not the median plane, see this illustration. --NorwegianBlue ^talk 13:45, 3 June 2007 (UTC)

Another way to put it is the median plane is a sagital plane which divides the body into equal left and right symmetrical pieces. --24.147.86.187 17:01, 3 June 2007 (UTC)

Careful about spelling. I believe "medial plane" is a common improper designation for the "median plane" (much like the "median nerve" is often mistakenly called the "medial nerve"). As others have described, the sagittal plane divides an object into two sides, right and left. Sagittal planes can be moved in a horizontal direction to change the size of the right and left sides. The position of the sagittal plane that divides the object into equal right and left halves is called the midsaggital (or median) plane. Cheers, David Iberri (talk) 20:06, 4 June 2007 (UTC)

Catheter ablation

Is catheter ablation effective for the treatment of arrhythmias?

Depends on the type of arrythmia. It is the treatment of choice for re-entry tachycardias, which are caused by abnormal signal transduction from the ventricles to the atria. However, whether it is possible or not depends on the localization of the abnormal pathway. See Wolff-Parkinson-White syndrome, Treatment. --NorwegianBlue ^talk 14:39, 4 June 2007 (UTC)

Radiofrequency abalation is also coming into use in the treatment of atrial fibrillation. A Maze procedure - previously performed by scalpel - can now be performed via catheter to isolate spots prone to fibrillation.

Frogs and lily pads

This is a tree frog on a leaf.

I was at a lake this weekend that had many lily pads, but I never saw a frog on any of them. Do frogs really sit on the lily pads or is that just something that people always assume from cartoons and popular culture? --Catrina

From what I remember (and I've never really paid attention to frogs since I was a kid), they don't really 'sit' on them for extended periods of time - but they do climb over/through them... --Kurt Shaped Box 23:03, 3 June 2007 (UTC)

I have seen many frogs sitting on tree leaves, presumably to take advantage of the natural camouflage. In a lake, hiding under the water may be the safest place, but while on the surface, the frog will try to seek a low-visibility spot such as a background it blends with. Nimur 01:17, 4 June 2007 (UTC)

I've seen small frogs sitting on lily pads before, hanging out and doing their frog thang. --24.147.86.187 15:08, 4 June 2007 (UTC)

June 4

Bug found in house

On three separate occasions recently I have killed a bug in the house. I would like to know what it is. I have reviewed books available in the local city library and have not been able to identify it and would appreciate any help in doing so and so find out about control measures. The creature is about 3 cm. long and an eighth in diameter. Its general colour is grey green and it has lighter pale yellow stripes running along its back. Its legs are at one end where it has noticeable eyes and two large antennae. It moves quite quickly. Any help or advice where to inquire further would be appreciated.

64.228.37.28 01:40, 4 June 2007 (UTC)tartan savage

It seems that this is a bug identification desk! Can you put up a picture? GB 06:56, 4 June 2007 (UTC)

Or at least tell us where in the world you are. --Anonymous, June 4, 22:23 (UTC).

Los Angeles cable landing station

It seems whenever I traceroute servers across the Pacific, for example in Japan or Australia, the packets are almost always routed through Los Angeles. Is that because there's an important cable landing point there? If so, where is it specifically, and do they give public tours for interested geeks? —Keenan Pepper 01:54, 4 June 2007 (UTC)

It's possible that your ISP goes through MAE-West or some similar internet backbone hub in Los Angeles. --Wirbelwindヴィルヴェルヴィント (talk) 04:51, 4 June 2007 (UTC)

When going to Australia the data would go via the southern-cross cable, which lands at Monterey Bay, or San Lui Obispo. I guess these are somewhere near Los Angeles. The big ISPs would have their main routers in the city rather than a cable landing station. There are six more landing points for cables going to Japan, spread along the US west coast. GB 06:54, 4 June 2007 (UTC)

For the record, neither Monterey nor San Luis Obispo is particularly close to Los Angeles. LA is at 34°03′N, 118°15′W, SLO is at 35°17′N, 120°40′W, and Monterey is at 36°36′N, 121°54′W. SLO is about 180 miles from LA, and Monterey is another 180 miles from there. --LarryMac | Talk 13:34, 4 June 2007 (UTC)

Okay, here's an example. When I traceroute vnet.cn (a popular Chinese site), I get this:

13  dcr1-as0-0.LosAngeles.savvis.net (204.70.192.117)  73.702 ms  74.835 ms  73.400 ms
14  * 208.172.44.2 (208.172.44.2)  77.881 ms  76.231 ms
15  202.97.51.61 (202.97.51.61)  282.940 ms  286.178 ms  285.422 ms

Now, 208.172.44.2 is obviously on this side of the ocean, and 202.97.51.61 is on the other side. Where is 208.172.44.2, and how do the bits get across the ocean to 202.97.51.61? —Keenan Pepper 20:41, 4 June 2007 (UTC)

Magic, of course! And 202.97.51.61 is actually Asia Pacific Network Information Centre in Beijing, China, with a PO Box mailing address in Australia. The 208.172.44.2 is registered to Savvis located in Los Angeles, CA, and mailing address in Cary, NC. --Wirbelwindヴィルヴェルヴィント (talk) 21:37, 4 June 2007 (UTC)

Our article on submarine communications cables has a number of useful external links to maps (including this PDF) showing cable landing points around the world. I couldn't tell you which one your particular packets are flowing through. TenOfAllTrades(talk) 13:52, 5 June 2007 (UTC)

Multi-coloured hair

What is the most likely cause for a person having multiple hair colours? Some genetic mutation during development? Is there any particular name for this? -- Consumed Crustacean (talk) 06:03, 4 June 2007 (UTC)

The most common reason is hair dye. Hair dressers can dye hair in different patterns, and as the natural colour grows out the roots change back their colour. I used to have brown and blond hair at the same time naturally (Long ago when I had hair), but that was due to sun bleaching. GB 06:49, 4 June 2007 (UTC)

There are some links in Heterochromia. Best regards, Dr_Dima.

The most likely cause is age. My hair is brown and grey. (The simplest answers are always the best!) SteveBaker 13:15, 4 June 2007 (UTC)

Human chimeras, though rare, do exist and can have varied hair color. This is also (more-or-less) the mechanism by which calico cats manage to have three hair colors in one cat.

Atlant 13:44, 4 June 2007 (UTC)

This question may also be about naturally occuring hair color. When a person bleaches or dyes their hair, it looks fake because it is all one color. Natural hair is multi-colored. For example, my hair is black, dark brown, light brown, and nearly blond. Overall, it looks brown. But, strand by strand, it is multi-colored. --Kainaw ^(talk) 15:40, 4 June 2007 (UTC)

I think I understand what you are saying. I myself have different colored hair. The hair on my head is an unremarkable brown, while the hair on my Face is distinctly red. Also when I was a toddler, my hair was light blond and curly. While these Google articles refer mainly to hair color patterns in animal breeds, the gentic principles would be applicable to humans. -Czmtzc 17:57, 4 June 2007 (UTC)

The most likely reason you have red facial hair but brown head hair is because you are heterozygous for a MC1R mutant allele. There is a strong genetic correlation between these (I too have that combination, and I genotyped myself to check!). Apart from different hair colours in different parts of the body, human hairs tend to be relatively homogeneous in colour. This is different in non-human animals, because they have the ability to alter the pigment that is "injected" into the hair as it grows. Infact, many animal hairs are banded, with two different tones along the hair shaft. This is known as the "agouti" pattern (named after the eponymous rodent). The agouti gene controls this banding and, depending on when the gene is expressed both temporally and spatially, you can generate all sorts of cool colour patterns. Humans do not have an agouti gene, and therefore lost this trick sometime during their evolution. There are plenty of other genes that cause different hair colours though. Piebaldism, caused by mutation is genes that control the migration, replication or differentiation of melanocytes from the neural crest during embryogenesis, results in white spotting. These genes include Kit, Pax3 and Microphthalmia. See here for some examples of the genetic mouse mutants that have been created or discovered with crazy pigmentation. Rockpocket 01:31, 5 June 2007 (UTC)

A somatic mutation in the scalp may give someone a silver streak in their hair. Bendž|Ť 18:11, 4 June 2007 (UTC)

Lots of people have multi color hair. In fact the famous ex-PM of Japan have multi color hair. He has two colors.

1 Black hair

2 White hair

202.168.50.40 23:17, 4 June 2007 (UTC)

DNP + fat loss

I've been reading a lot about this lately, and even saw it on wikipedia, but im wondering if its really safe. I know you sweat like hell, makes your hot and all that, and I read about cataract reports, dehydration, and all that, but other than that, is it really unsafe?

Also found some info here: http://forums.steroid.com/showthread.php?t=145408&highlight=2%2C4-dinitrophenol

Its a steroid website, but DNP is not a steroid, I just ran into that site with a google search and it had the most info.

Since DNP reduces the mitochondrial function (works in a similar way to thermogenin) it could well be described as a poison. If you get the dose wrong the mitochondria may well not function enough for a person to perform normal activities (i.e. will not produce enough ATP). What is the right dose? Presumably its different for everyone? Given the uncertainties it does not sound like a healthy way to lose fat, not to mention it is banned by the FDA (Don't have ref on hand). David D. (Talk) 08:24, 4 June 2007 (UTC)

Note: thermogenin is only present in fat cells whereas DNP will function in all cells. Just because the uncoupling function (via thermogenin) is known as a normal process in fat cells it does not make DNP safe. David D. (Talk) 08:31, 4 June 2007 (UTC)

A quick search comes up witht he following health warning from Sonoma county.http://www.sonoma-county.org/da/DNP_alert.htm

"The young man's death was reported to the State Health Department by the Long Island Poison Control Center, which indicated that the individual apparently ingested 600 milligrams of DNP a day for four days."

"According to the Agency for Toxic Substances and Disease Registry, it was sold in the 1930's in diet pills but was banned in 1938 because of severe health effects. Dinitrophenols are toxic to the liver, kidney and nervous system. The chemical causes hyperthermia (increased body temperature), dehydration, tachycardia (rapid heartbeat), restlessness and manic behavior and convulsions which typically signify an immediate lift-threatening intoxication."

"Although DNP use in diet pills was banned in 1938, it is currently being marketed and used by body builders, and is also advertised and marketed on the Internet. The extent of its use is unknown at this time."

Hope thgis gives you an idea of the dangers involved by using DNP as a quick fix for weight loss. David D. (Talk) 18:32, 4 June 2007 (UTC)

I read all of that, but lets say if someone were to only use it for a week lets say. Not in huge amounts, not like the 600mg someone mentioned, and were to stay cool and drink lots and lots of water. Its funny that you mention rapid heartbeat, because most users use ECA (ephedra, caffeine, aspirin) with it to give them energy, and it would seem if the DNP already gave you a rapid heartbeat it would be just too much, so I think thats a rare side effect. I read thats its both liver and kidney friendly, and based on many many users, ive never heard of any kidney or liver problems.

What I was really wondering, as David mentioned above, that it reduces mitochondrial function, so if it doesn't reduce it too much, does it mean the drug is somewhat safe? And is raising the body temperature a degree or two very dangerous? I heard you can get a seizure from a pharmacist if you raise the body temperature, but I never heard of this happening in users from reading user logs. I also noticed if it was banned by the FDA, but if taken in short intervals, I don't think the liver/kidney problems, if any are an issue and I don't really think that the FDA thinks that sweating like crazy nonstop is an acceptable side effect, and that may be another reason that its banned, but if someone can deal with it on the short term, is this drug really that dangerous?

I also haven't read of any long term side effects in short DNP use, have you guys seen any? (Other than cataracts in long term use happening exclusively to women) —Preceding unsigned comment added by 76.167.136.84 (talk • contribs)

Why would anyone risk taking a chemical that makes their membranes leaky to protons (hydrogen ions)? This chemical will affect all cells, not just the fat cells. I suspect that the FDA thinks it is an unacceptable risk to be shutting down the mitochondrial function in all cells. i doubt they worry about excessive sweating. Cyanide also works by killing mitochondrial function. Clearly this is an extreme, and irreversible, example but that is the type of toxin you are dealing with if DNP is taken in high quantities.

Speculation ALERT Since DNP uncoupling mitochondria is not as drastic as killing the function of complex IV (the target for cyanide), I assume the death would be slower if too much was taken. Clearly the doses used by body builders are less than the toxic levels, but I expect the FDA probably regards it as an unacceptable risk (too close to toxic levels), especially in a culture where many think more is better.

In summary, clearly it is not always lethal since body builders are using it. But getting the dose right will always be tricky and potentially dangerous. David D. (Talk) 21:21, 5 June 2007 (UTC)

Thyroid Function

Is there anyway one can increase thyroid function to normal levels after something has caused it to decrease? (something such as a medicine, dieting, etc)

There are medicinal ways to do it. See hypothyroid for more info. Dismas|^(talk) 16:46, 4 June 2007 (UTC)

The article only mentions thyroid replacement therapy with such medicines as Synthroid under medical supervision after T4 and TSH levels are tested to verify there is in fact low thyroid. Edison 22:57, 4 June 2007 (UTC)

Thats not what I am asking. Heres a little bit more explanation. Lets say someone has normal thyroid function, but wants to lose weight. So he or she goes out and takes cytomel (T3) or synthroid (T4) or a pill that has both. The thyroid will stop producing thyroid hormones because he/she is taking it in pills. Now after the person stops using the pills, the thyroid will slowly restart producing the hormones it does, but it will be slow and it will take some time for it to be functioning at normal levels. In this time, the person can gain all the weight he/she has lost. Is there anyway to jumpstart the thyroid into normal production levels right after discontinuance of the thyroid hormone pills. I read that this is possible with Human chorionic gonadotropin (hCG) or clomid, but I have never heard of anyone doing this and I am not sure if it works. So I am wondering if anyone knows anything about this, and if it works, how long it takes to work, etc... Thanks

The literal simple answer to your question is No. Your question and your ideas about the relationship between thyroid and weight might be based on some erroneous information. Following is a fuller explanation. Doctors discovered about a century ago that adults with severe thyroid failure usually gained weight, and had a slow metabolism and sedentary proclivity. When they were given thyroid extract they became more active, their metabolic rate rose, and they lost weight and it stayed off. There were no reliable tests of thyroid function for the first half of the century, so any adult complaining of weight gain and lack of energy was likely to be given a trial of thyroid extract. For many people it did not work. By the middle of the 20th century, it became possible to test for thyroid function at least crudely. To no one's surprise it turned out that people whose thyroid tests were low were much more likely to get measurable benefit from treatment and people whose thyroid tests were normal were more likely to have hyperthyroid side effects (like rapid heart rate) and minimal measurable benefit (even if they had some temporary, subjective, placebo benefit). It also became steadily clearer that weight regulation depended on far more complex hormone and signal systems than simply thyroid hormone levels. So intelligent, honest doctors who were trying to help but not harm their patients stopped prescribing extra thyroid hormone as a weight-loss pill to people with normal thyroid function. If it worked and was safe, over half the adults you know would be taking it. It doesn't and it isn't. alteripse 19:52, 5 June 2007 (UTC)

Wait, lets backup one second. I am not trying to flame anyone, but telling me that my ideas between the relationship and the thyroid are incorrect is ridiculous. I never said self treatment using any thyroid hormone is "safe," never ever did I say that, nor did I say it was smart. If it was safe than we would not have overweight or obese people. But lets get something very very strait here. It does work, and if you think for one second that it does not, I think you need to do a little bit of research before you tell other people that you know more than them, and tell other people that what they know and what you don't know is erraneous information. As much as I appreciate your time and your response, I do not appreciate the words coming out of your mouth. If you do the least amount of research, I mean just a 5 second search in google, you will come up with a countless number of sources, forums, boards, where people, especially bodybuilders, have used thyroid hormones to shed weight quickly and effectively, notice I never said "safely," I said quickly and effectively. It might not be safe, or smart, but it sure does work, and that is someone you cannot argue against. And once again, my original question has not been answered.

Sorry to give offense, but you are doubly incorrect. Your original question was indeed answered; you just don't like the answer. As for the rest of your ideas, rather than say "countless sources", why don't you offer us a single source, just one, that contains strong evidence that use of extra thyroid hormone by overweight but not hypothyroid people can cause sustained weight loss? I know of no such evidence and would be indebted to you for the education. Put your source where your mouth is, please. alteripse 21:04, 5 June 2007 (UTC)

Wait a minute, if this is a disagreement over "safe", I bow out. There are a hundred destructive things people can do to lose weight and I will not engage in discussion of stupidity but will defer to the experts. alteripse 21:08, 5 June 2007 (UTC)

life of plastics

What are the factors that govern or extrapolate life of plastics?

1. The kind of plastic (acrylic glass lasts a lot longer than cellulose).
2. The environment (most plastics wouldn't last too long in the center of the sun).
3. What you mean by "life" (Does it have to look shiny and new? Does it have to hold its shape? Or does it only have to be detectable?) —Keenan Pepper 20:27, 4 June 2007 (UTC)

Indigenous peoples of the Americas

Is there any link which describes the different physical features of the Indigenous peoples of the Americas? Especially those who are from Alaska and those who are from Peru.

I normally see them broken into three groups: The Aztec/Inca/Mayan group. There are many theories about where they came from. I don't know what the latest accepted theory is. Then, there is the first wave of Asians that came over and populated North America. Finally, there are the current Inuits that came over from Asia also. That is a terrible over-simplication, but you can see how the North American/Inuit people are related as coming over from Asia. As for differences in appearance, the assumption is that they came from Asia. Look at the differences in appearance of the Asians. --Kainaw ^(talk) 13:18, 5 June 2007 (UTC)

You may also want to read Clovis culture.

Atlant 15:56, 5 June 2007 (UTC)

Being fertile

I don't know if I am fertile or not? Now I have had wet dreams but everytime I masturbate I don't make semen. Could I not be fertile over not making semen while masturbating? Heegoop, 4 June 2007 (UTC).

If you have medical concerns, I suggest asking your doctor. Friday (talk) 19:20, 4 June 2007 (UTC)

Yes, don't be afraid to talk to your doctor. Also, the answer depends on how old your are. If you're in your early teens, it's probably normal. —Keenan Pepper 20:22, 4 June 2007 (UTC)

Do bear in mind that producing semen isn't what's important for fertility. It's producing sperm. You could produce copious amounts of semen but would still be infertile if you aren't producing any sperm. Of course if you're producing sperm not semen you'd have fertility problems as well but anyway as Keenan mentions depending on your age it might be perfectly normal and if you're concerned you should see a doctor. N.B. I presume you're male. If you're female and complaining about not producing semen, you really, really need to ask your parents or someother trust worthy adult about sex and human biology Nil Einne 17:26, 5 June 2007 (UTC)

June 5

Binary Planets

How do I figure out the relative masses and distances it would take for two planets to both:

1) Orbit each other with the barycenter outside of the larger, making them a binary planet system instead of a planet and a moon?

2) Orbit each other without spinning off to become separate planets, and without colliding?

If it matters, the small one also needs to be tidally locked to the big one. --67.110.213.253 03:20, 5 June 2007 (UTC)

For Part 1, you need to calculated the center of mass of the system, and determine if it is located inside or outside the larger mass. (The linked article has a formula for calculating the barycenter of a two-body system.) TenOfAllTrades(talk) 03:38, 5 June 2007 (UTC)

For 2): See Hill sphere. Icek 08:28, 5 June 2007 (UTC)

Questions about wasps

I have some problems with a wasp (north-european kind) in my apartment.

1) How long will it live, if it doesn't have access to food?

2) Does it eat anything which is likely in my apartment? Ie, should I assume that it will find food?

3) What are some of the best ways to get rid of wasps, assuming you are absolutely chickenshit around them?

Thanks an endless bunch. 213.161.190.228 05:14, 5 June 2007 (UTC)

Question 1 - see question 2. Question 2: it will always find food. Adult wasps can eat most human foods, cooked or raw. Larvae in nests need high-protein food (chewed-up insects by default, but any meat product seems to do just fine as long as the adult wasp has chewed on it for some time). Question 3 - do you have one wasp or a nest?! For one wasp - open the window :). For a nest, call pest control. And, BTW, there are several "north-european kinds". Try German wasp, Common wasp, European paper wasp, European hornet for the common ones. Cheers, Dr_Dima.

Question 3: For a single wasp (or a small number of them), and manageable level of chickenshit-ness:

1. Find a drinking glass or empty glass jar.
2. Find a piece of cardboard large enough to cover the glass.
3. Wait until the wasp is sitting still on some reachable, flat surface like a wall.
4. Slowly place the glass over the wasp.
5. Slide cardboard under the glass.
6. Carry glass+cardboard+wasp as a unit outdoors or to an open window.
7. Swing the glass with a throwing motion and simultaneously remove the cardboard, to fling the wasp far away.

--mglg_(talk) 17:17, 5 June 2007 (UTC)

Some additional points:

• You want the vessel you use to be large enough for it to be easy to bring down over the insect, but lightweight. A plastic wastebasket might be more convenient than a glass.
• It may be easier to slide the vessel over the cardboard than the cardboard under the vessel.
• You can reduce the fear level by wearing a heavy coat, gloves, hood, etc. while doing this. You know it can't hurt you if it can't get close to your skin.

I once had a single wasp come inside my house at night, and settle on a place where the above tactics would not work. Below is a slightly edited copy of the email I sent to some friends at the time: it's longer than the usual RD posting, but it is on-topic.

Click "show" to read the long anecdote
The following discussion has been closed. Please do not modify it.
(Begin anecdote) So about an hour ago I opened the front door to put out the gray-box recycling, and I noticed that our new "neighborhood Yellow Pages" booklet had been delivered. I was taking down the old booklet, intending to add it to the gray box, when something flew by my ear with a loud buzzing sound. I looked around and there was a large insect circling around the dining-table area -- and it appeared to be black and yellow. I quickly turned the kitchen lights off, and then other lights until the only ones shining inside the house were the front lights in the living room. Both front and rear lights were on outside, as I had been about to take out the recycling through both doors. Within half a minute the wasp had done the expected thing and was circling around one of the remaining lights, and I could see clearly that it was a wasp -- a big one, body length close to 3/4 inch. After a while it got bored with this and landed on the vertical blinds near the light. But what it didn't do was go anywhere near the front door. I temporized by moving the gray box to the back door so I could take it out that way if I got the wasp to go out the front, and adding the old booklet to it. The wasp temporized by doing nothing. Now what? (Did I mention that I'm kind of terrified of wasps and such?) (Did I mention that my wife was upstairs sleeping through all this, accopanied by both cats?) I have a can of spray insecticide that I got when we were having trouble with ants this summer, but it comes with so many cautions I've never dared use it inside the house (for the ants I sprayed the front and back door sills), and I don't know how quick its action is if sprayed directly on an insect anyway. I could try killing it by swatting with a newspaper or something, and I'd probably have a good chance, but it was flying around pretty fast and I might miss, in which case I'd be setting myself up for a sting for sure. And besides, it would have to be on a hard surface -- the vertical blinds wouldn't do! I have on occasion attacked insects by spraying them with water or alcohol, whatever was handy in a spray bottle, to impair their flying ability before moving in for the swat. But this one was moving so fast that I wasn't confident enough of slowing it down enough before being stung. I could try trapping it in a wastebasket -- conveniently, I had several at hand that I'd just emptied -- but again, not on the vertical blinds. And if it went to the ceiling, it'd be hard to catch it as well, because the living-room ceiling is fairly high. Once again I might expect to be stung. I could try "herding" it with something like a magazine or a newspaper section. That might work if it was only a little way from the front door, but it wasn't; it was at least 6 feet away. I couldn't see myself herding it that far without you-know-what. Opening the front window and taking the flyscreen off was right out -- I'd first have to open the vertical blinds. Hmm. While I was thinking I put the coat I'd been wearing today back on, and my gloves. Then I put a chair by the front door and set a flashlight on it, switched on, so that it was pointing diagonally up along the plane of the vertical blinds directly at the wasp. I wasn't sure if it would respond to a bright light shining from below, but there wasn't any way to stand the flashlight at a high level in the right place. (Did I mention that I'm kind of terrified of wasps and such?) I switched off the last remaining ordinary lights inside the house, stepped back to a safe distance, and hoped to see the wasp fly to the flashlight. If it did, I would quickly open the door and so expose it to the bright porch light, which presumably is what had attracted it to the front door area in the first place. It didn't take off. I waited, keeping my eyes almost constantly on the wasp in case it flew outside of the flashlight beam and I lost track of it. I kept my hand near a light switch in case I had to find it again. And waited. The wasp had apparently reacted to the darkness by going to sleep! I mentally reviewed my other options, but nothing new emerged, so I continued to watch and wait. (Did I mention that I'm kind of terrified of wasps and such?) After about 5 minutes, the wasp slowly began to move -- it turned toward the flashlight and started walking toward it! It would have to traverse about 20 slats of the vertical blinds, one by one, moving diagonally downward all the time, if it was willing to do that. In fact it covered about 12 slats and then stopped and started moving up the slat. I realized that while the flashlight might have been a target as well, it had also been following the lighted area where the beam was playing on the blinds. But as it got closer to the light, it got to the narrower part of the cone of light, and the blinds were no longer illuminated. I could see nothing else to do. I stepped forward, picked up the flashlight, and shone it on the blinds to the right of the wasp, holding the light itself farther to the right -- and since I was holding it, I could shine it horizontally, not diagonally requiring the insect to move downward. And sure enough, this worked. The wasp turned back to the right and continued its slow walk. At least I was less afraid of it now -- apparently the darkness really had made it sleepy, or slow and cautious, or something. It wasn't making any sudden moves any more. My method worked until it reached the last slat, when I hoped to just open the door and watch it fly outside. I tried opening the door, but it appeared not to notice the lighted area -- as if it was outside its field of view. Instead, it just moved around on the slat -- and whatever I did, now it insisted on going upward. I tried taking the slat it was on and twisting it so the wasp could see the door better, but it was the wrong direction and it wouldn't move far enough. For a while the wasp stayed around the top of the blinds, just inches from the door but out of sight of it around the corner. Once or twice it even went into the vertical-blind drive track. It never took off, just kept moving at a crawl. Finally by use of the flashlight I managed to get it to come out and down again. Then I pushed the slat up against the wall, and by careful placement of the flashlight got the wasp to move onto the convex angle where the window wall meets the door wall. I now opened the door again, but the insect still didn't move toward it. I tried various things. Finally I decided that since it was usually responding to the flashlight, I would turn off the outside light as well, and use only the flashlight until I had the thing closer to the door. This was starting to work -- and then the wasp suddenly moved fast. Since I was now quite close to it, this caused the other thing I was afraid of to happen -- I lost track of where it went. I quickly snapped the inside light back on, then a couple of seconds later realized that I'd hit the wrong switch, turned it off again, and turned the outside light back on. Surely this was too quick for the wasp to react. But where had it gone? I couldn't see it outside, but I couldn't see it inside either, anywhere near where it had been. And it clearly wasn't going to move into the dark parts of the room. Had it, then, gone outside and flown away? I decided to close the door, and as I did, I glanced down at the floor where it was about to sweep across. Good thing I did -- there was the wasp! It must have fallen from the wall, too sleepy to fly right, and that was the sudden move. In retrospect I think I could have safely killed it at this point by just stepping on it, but I stayed with the original plan. I picked up a magazine and simply herded the wasp the last few inches to the door sill and out. And slammed the door. WHEE-EW! (End anecdote)

--Anonymous, June 5, 22:50 (UTC).

Exclusion principle and electrons in atoms

I may have misunderstood bits of it, but Pauli says that a system (an atom) must have half-integers that cancel one another out. What if there are three electrons, two of opposite spin to one another, and a third which has its very own kind of value? Am I to understand that the concept of zero wave function as something which is localized to only two half-integers? Otherwise the third electron would mess a bit with that. Is the wave function (and it being zero or not) directly related to how stable an atom (or electron within it) is? I'm thinking about how atoms with odd numbers of electrons seem less stable than those with pairs. Thanks for any clearing up. 213.161.190.228 05:43, 5 June 2007 (UTC)

you seem to be confused about the physical meaning of eigenvalues, or more generally of the quantum numbers characterising spatial and spin part of a single-electron wavefuncton, for an electron in an atom. Is this because of the wasp that was bothering you in the previous question ;) ? I would guess the "half-integer" you are talking about is spin (it could be total angular momentum, too, or its projection; but forget about that for a moment). There is a spin eigenvalue s which is always 1/2 for an electron, and spin projection eigenvalue s_z which can be either plus 1/2 or minus 1/2. For spatial part, there is a principal quantum number n, angular orbital quantum number l, and its projection l_z. Pauli principle says that switching any two electrons must change the sign of the total wavefunction; if the two electrons were to occupy the same state, the total wavefunction would be equal to minus itself, and thus be identically zero everywhere. Hence, two electrons can not occupy the same state. Could you please rephrase your question in these terms? Cheers, Dr_Dima.

It's a little bit like the game of Set: no two electrons can be the same in every way, but they have several independent properties to think about. Just like set cards have color, hatching, number, and shape. Electrons have "quantum numbers" n, l, m, s. The n, l, and m are the "spatial part" of the wave function, as Dr Dima described, and the s is the "spin part," which is totally independent and can be ±½. If you have two electrons, they can both have the same lowest-energy value of n, l, and m, with s=+½ and s=-½. As you add more, they have to have higher n and higher energy to satisfy the principle that each one has to be different from all the others in at least one respect. --Reuben 06:44, 5 June 2007 (UTC)

For electrons, spin is only one of four properties. Only when all four are the same does the Pauli exclusion principle apply (i.e. they can;t iccupy the same space). Also see Fermions and Leptons and Bosons--Tbeatty 06:55, 5 June 2007 (UTC)

That's exactly why I mentioned the game of Set: four properties, and no pair of cards can share all four. --Reuben 17:25, 5 June 2007 (UTC)

Greenland map, no ice

Like 5 or 6 years ago, in my oceanography class in high school, my teacher had on the wall a map showing greenland under its ice sheet, as well as naming all the sea floor expanses and trenches around it. Not a 'if the ice melts and sea levels rise' map, but just, it lifted off, photo snapped map. The image was spectacular, Greenland looked like a giant backward 'C' with a huge bay in the middle. I want to try to find an image of that map, or any one done the same way (no ice on top, just the land under the ice). After months of on and off Google image searches for awkward combinations of greenland, no ice and map, I decided to give my fellow editors a shot. Anyone able to find such an image? The map in the classroom was published by the Navy Press or something similar out of Annapolis, Maryland, but im not hung up on that particular map so long as it is the same style. -M^ask? 06:07, 5 June 2007 (UTC)

Something like this? Try a Google image search for Greenland subglacial topographic map and variations thereof. Maelin (Talk | Contribs) 09:30, 5 June 2007 (UTC)

Exactly! Thank you, I'll do my own poking with the new terms looking for a more detailed image. Thanks a bunch! -M^ask? 16:35, 5 June 2007 (UTC)

Earth's hot core.

Why is the core of the Earth so hot? Is it just a pressure thing? Chemical reactions? 213.48.15.234 07:06, 5 June 2007 (UTC)

Great question! There is a short section addressing it in Structure of the Earth. My understanding is that radioactive decay of unstable elements, along with pressure due to gravity keep the Earth's interior heated. --TeaDrinker 07:12, 5 June 2007 (UTC)

Constant pressure does not create heat. It's thought to be mainly radioactive decay. Icek 08:32, 5 June 2007 (UTC)

Very interesting, thanks. It's amazing how little we know about the termperature and its causes, and the material of the core. 213.48.15.234 09:10, 5 June 2007 (UTC)

Radioactivity (along with crystalization of the inner core and primordial heat of formation) provide the energy, but the main reason it is hot is because it is surrounded by thousands of kilometers of poorly conducting rock. The energy sources involved are actually quite puny (much much weaker than sunlight, for example), but because the rock is a poor conductor the heat accumulates. It's like wrapping yourself in many thick blankets. The blankets don't generate heat, but they trap the heat you do generate and cause temperatures to rise. For the Earth, the end result is temperatures in the core that are similar to temperatures at the surface of the sun. Dragons flight 09:20, 5 June 2007 (UTC)

Thanks, I had realised this, my first reaction was "wow, that much heat from radioactive decay?!", but then realised that the energy doesnt really have anywhere to go. (I'm a physicist by training). Does this mean that a few billion years ago the core was significantly cooler? Is it still getting hotter? Or has it reached the equilibrium point and is slowly cooling as the radioactive sources get less active? 213.48.15.234 09:38, 5 June 2007 (UTC)

No, we are cooling, just very slowly because of all that rock. Radioactivity and the latent heat of crystalization of the inner core slow the process, and arguably there is still a component of primordial heat of formation (though not everyone agrees on that). Primordial heat and radioactivity both diminsh with time. At the present time, the growth of the inner core provides a thermal buffer, but eventually the entire core will solidify. This is believed to have already happened on smaller bodies, like Mars. For the sake of scale, the Earth currently dissipates about 40 terawatts of geothermal energy to the surface (where it eventually radiates into space). Dragons flight 10:12, 5 June 2007 (UTC)

You can have one too: *. 213.48.15.234 10:18, 5 June 2007 (UTC)

That is an excellent question indeed, and one that was discussed in depth by the leading scientists after the Stefan-Boltzmann law discovery but before the extent of Potassium-40 and heavy element radioactive decay in the core became apparent. Indeed, people know for nearly 100 years now that Earth radiates more heat into space than it receives from the Sun; too much to be explained by the thermal energy reserve left over since the Earth formed and compressed. So the answer to your question is no, it is not just pressure (that was most important while the Earth was forming and compressing rapidly), and it is not chemical reactions. It is mostly radioactive decay, as TeaDrinker and Icek told you already; plus a minor contribution from tides, converted to heat by viscosity and friction. BTW, research into exact heat balance of the core is still very much ongoing, there are new findings being published rather regularly on the science news sites. Cheers, Dr_Dima.

The answer to your second question (regarding the equilibrium or, strictly speaking, the steady state) is not really known, since the core temperature can not be directly and precisely measured. The leftover heat is slowly dissipating, and radioactive material quantity in the core is slowly dwindling; so there is a consensus saying that eventually, in billions of years, the core will cool down and solidify completely. (Actually, the Sun will probably become a red giant and engulf the Earth sooner than that). But I do not know of any reliable measurement or simulation of recent history of core tempeartures. I would expect the temperature to fluctuate slightly, on the same time scales as the Earth magnetic field; but to decrease on the largest time-scale. Dr_Dima.

That verfies what I was thinking about it too. Thank you for this discussion. Have a text-barnstar. Because I can't work out how to do barnstar stuffs: *. 213.48.15.234 10:03, 5 June 2007 (UTC)

You are welcome! Thanks, Dr_Dima.

Ping times towards a destination in Africa

When experimenting with "ping" towards a destination in Africa, I saw a 450 ms delay between two routers (adding to the overall round-trip-time). The obvious hypothesis is a satellite link. A geostationary orbit is about 36000 km above the equator; thus a ballpark estimate for round-trip time of radio signals is 240 ms 480 ms if I could total RTT (I'm a fool). Of course, the stations are not exactly on the equator, so it is normal that it should take longer, but it does not explain such a large increase. Is the difference due to error-correcting codes, error correction protocols or similar? (I know error correction explains the latency on ADSL lines.) David.Monniaux 08:46, 5 June 2007 (UTC)

Is the 450ms one-way or return? --antilived^{T | C | G} 10:24, 5 June 2007 (UTC)

Yes, how did you get the $450\,\mathrm {ms}$ number? —Bromskloss 10:32, 5 June 2007 (UTC)

Most round-trip ping times are nowhere near the speed-of-light transit times. Most of the time elapsed has nothing to do with the amount of time the bits are actually moving from place to place. Instead, longer ping times result from the time required for your data to queue up and be transmitted from one server to another, and on how rapidly the final destination server responds to your request.

The ping time to my local ISP is about 10 ms, but that shouldn't be interpreted to mean that my ISP's office is 3000 km away. Incidentally, it is my understanding that the bulk of transoceanic data now travels via submarine fiber optic cables; satellite links don't have nearly the capacity of optical fiber. TenOfAllTrades(talk) 13:48, 5 June 2007 (UTC)

Er... I get 1ms ping times or so when I'm at work, because we have an optic fiber connection to the backbone. I get ping times of several dozen ms to my ISP because the ADSL box has big internal queues, which are necessary for error correction (my ISP offers the possibility of "fast path" ADSL, which reduced latency / ping times, for people who have a good and short phone line and thus do not need complex error correction.

You are correct in stating that most intercontinental traffic goes through fiber optic cables. However, they yield much shorter ping times, which are in my experience nearly consistent with the speed of light in optic fiber (300000km/s over the optical index, which is around 1.5). David.Monniaux 19:37, 5 June 2007 (UTC)

Satellite links also have much longer round-trip delays than do submarine cables, owing to the unavoidable speed-of-light problem travelling 22,000 miles up then 22,000 miles down, then back 'round again. That's about 470 ms of delay, minimum.

Atlant 15:59, 5 June 2007 (UTC)

Bear in mind that there are often silent routers and the like. Also, it's easily possible the link is satured. Nil Einne 17:23, 5 June 2007 (UTC)

For a geostationary satellite, the minimum one-way delay is 238ms, where both hub and remote are directly under the satellite. The maximum one-way delay is about 280ms (where the satellite is on the horizon from both hub and remote.) Thus, the minimum round-trip delay with a satellite link is 476ms. the maximum can be any number greater than this based on the terrestrial part of the path. Since your delay is less than 476ms, you are not using a satellite round-trip. It is possible that you are using a satellite downstream with a terrestrial upstream. -Arch dude 18:31, 5 June 2007 (UTC)

Argh! I'm a fool! I did 2*36000/300000 instead of 4*36000/300000, which gives .480 and is fully consistent. Silly idea: round-trip-time includes 4, not 2, trips and from the satellite... The "about 450" was a difference between ping times and is thus not very precise, it's most probably more. David.Monniaux 19:37, 5 June 2007 (UTC)

arunbrainy

I have some ques. 1.what is crystal axis? 2.when one substance is rubbed against another substance,frictional electricity is produced.then from which substance the electrones are transferred to the other substance?

I'm going to guess you need to read up on piezoelectricity and maybe crystallography As far as actually answering your questions, I'm not sure I can be of any help, Sorry! Root⁴(one) 15:55, 5 June 2007 (UTC)

Ooops, after rethinking what you might be asking, I note when charge is built up due to increased surface contact via friction, and not stress on a crystal (piezoelectricity), that is static electricity. As to knowing which of two substances will get the negative charge, that's a good question! (Again, I can't help out). Root⁴(one) 16:02, 5 June 2007 (UTC)

The article you need to read for question 2 is triboelectric effect. For question 1, crystal structure and its "see also" links may be helpful. --mglg_(talk) 17:05, 5 June 2007 (UTC)

Prozac

I understand that I am not allowed to ask for medical advice, but wanted to ask about Prozac. My GP prescribed me Prozac this morning and this afternoon I feel lightheaded, giddy and nauseous. Does Prozac take effect this quickly or are these more likely to be side affects - I understand the lightheadedness and giddiness could be connected. 194.168.231.2 13:12, 5 June 2007 (UTC)Wes.

The best people to ask about this would be your GP or your pharmacist. Give them a call; they're there to help—and they're actually qualified to give this sort of advice. We're not able to advise you on what your symptoms may mean here at the Reference Desk. TenOfAllTrades(talk) 13:37, 5 June 2007 (UTC)

If you want a list of side effects, see Fluoxetine#Side effects. --Kainaw ^(talk) 13:39, 5 June 2007 (UTC)

See all the blah-blah disclaimers, but I can give my personal experience. I was on everything, including Prozac, but now I'm on Celexa. I found the Prozac effect was instant, including the symptoms you mentioned. It goes away in a day or so. The first week will tell if you can take it, then you will notice the positive effects in a month. It takes several months for full effect, and then you can evaluate with your doctor. If you find you are having trouble, you can ask for a specialist psychiatrist. Most people go through several dose attempts, and several types of anti-depressants. --Zeizmic 14:52, 5 June 2007 (UTC)

Thanks Zeizmic, I don't believe I am feeling an instant effect, probably the light head caused dizziness and made me feel giddy coupled with the relief of receiving a perscription. I already see a clinical psychologist but progress feels painfully slow. Doctor warned me of nausea and headaches but that was all the information I received and nothing with the pills. Had read the article but guess I just wanted the reassurance that someone else had experienced similar side effects. Silly I guess. Cheers again people. 194.168.231.2 15:19, 5 June 2007 (UTC)Wes.

For perspective, a psychologist and psychiatrist are significantly different (each has their own article!). Psychiatrists are medical doctors with a specialization in mental health and well-being. (Clinical) Psychologists are not medical doctors but often have advanced degrees (such as a Ph.D) in psychology. Psychologists can not usually prescribe medicine directly. Some individuals qualify as both psychiatrists AND psychologists, though this is rare. Good luck with your medication, Nimur 17:06, 5 June 2007 (UTC)

Should zeaxanthin and lutein be called vitamins?

As far as I know, animals, at least mammals, are not able to synthesize carotenoids. I think it is strongly suspected that low blood plasma levels of lutein and zeaxanthin lead to illnesses of the retina, where these carotenoids usually occur in larger concentrations. Then why are they not "officially" declared vitamins? Icek 16:54, 5 June 2007 (UTC)

I don't know the answer for this. But the symptoms of most vitamin deficiencies are quite severe and so they were usually recognised fairly early on. Also, these vitamin deficiencies (and therefore the syndromes associated with them) were common enough that they could be recognised. From the sound of it, the symptoms of lutein and zeaxanthin deficiencies are either not that severe or so rarely observed that they are still only beginning to be understood Nil Einne 17:17, 5 June 2007 (UTC)

According to Wiki, lutein and zeaxanthin, as well as lycopene, are included in the vitamin list under vitamin A definition. Please see Vitamin and Carotenoid. Dr_Dima.

Dead Gill

For the last what ever my fish has stop all use of one gill! Im afraid something maybe wrong! can ya help?--Lolichan4u 17:05, 5 June 2007 (UTC)

Universe

How did the universe start? Where did all of the matter that makes up planets come from?

Is there a God?

See History of the universe and Existance_of_God for encyclopedia articles on these topics. Friday (talk) 17:53, 5 June 2007 (UTC)

As far as what can be verified through personal experience, the universe began when you were born. It ends when you go to sleep and begins again when you wake up. Or, the more scientific view is that it began with the Big Bang. Vranak

Starvation in cats causes liver disease?

I read an article the other day about overweight cats, and what to do and what not to do. The article said that one should never starve a cat because they could develop deadly liver disease. Why? How? After how long starvation? Thanks in advance for answers. Jack Daw 18:44, 5 June 2007 (UTC)

It's called fatty liver disease, or hepatic lipidosis, and it usually only happens in overweight cats. Generally it takes at least a few days of starvation (or anorexia secondary to stress or diet change) to occur. It's caused by mobilization of fat for energy, which subsequently accumulates in the liver and causes liver failure. It is reversible, but treatment is intensive and usually involves a feeding tube. Here's more information [1]. --Joelmills 20:12, 5 June 2007 (UTC)

Ichthyosis vulgaris

I have a mild form of Ichthyosis vulgaris. I read the article in Wiki about it however I read somewhere that there are additional symptoms that one can have such as hyperlinear hands and feet and rhinitis. Are there any others that I am missing? --Juliet 19:01, 5 June 2007 (UTC)

• Check the third reference (MedlinePlus) at the end of the article. 69.201.182.76 22:19, 5 June 2007 (UTC)

Do you have a link? --Juliet 12:42, 6 June 2007 (UTC)

If I reduce the pressure of a packet of air in space, will it still get colder?

From either the ideal gas law or adiabetic cooling, we know that if we decrease the pressure of a packet of gas the temperature should drop. Supposedly, this is because the air is doing work on its surroundings as it expands, or something.

If I take a box of air into space and make a hole in it, the pressure will decrease very rapidly. But it won't, as far as I can tell, be doing any work on its surroundings. Will the temperature of the air decrease? If it does decrease, can someone please explain it to me without using abstractions, but actually from an atom's-eye view: how is an individual atom losing kinetic energy? As far as an atom's concerned, it was just heading towards a wall that was suddenly not there anymore!

Thanks so much for any help! --Mike 19:49, 5 June 2007 (UTC)

It sounds like what you're describing might be a hypothetical case where the pressure and number of moles of gas in a system are decreasing in equal proportion while the volume and temperature of the gas remains the same. In terms of the ideal gas law, PV=nRT, you might be seeing P and n decrease in the same proportion, leaving V and T constant.

I don't think this is the same as expanding gas in a cylinder piston. In that case the gas molecules are expending their kinetic energy to expand the volume of the cylinder by pushing the piston. So if the temperature rises, then either the pressure or the volume or both will increase. And if you manually raised the piston from outside to increase the volume, then you'd probably see the temperature remain constant but see the pressure drop in proportion to the increase in volume.

Of course that's all hypothetical, and I can't claim to be an expert. But basically variables other than temperature in PV=nRT can change when you change something in the enclosed system. Dugwiki 21:18, 5 June 2007 (UTC)

By the way, as long as I'm speculating, I should mention that it also follows that when you open a valve to let gas out of a system, it's quite possible that the most energetic gas molecules will be the ones most likely to escape the system. After all, the faster an individual molecule is moving the more likely it is to be able to escape through the open valve before the valve shuts. Therefore when you open the valve to space it's quite possible that on average you have shunted off molecules on the higher end of the kinetic energy spectrum of the gas, thereby lowering the total average temperature of the remaining system. That would be, I think, a case of adiabetic cooling where the temperature and pressure and number of moles of gas all change simultaneously. Dugwiki 21:28, 5 June 2007 (UTC)

See this article: [2]. Seems you're right, no work, so no decrease in temperature for ideal gases. (Real gases can give a different result!) Also see Boomerang nebula, which is similar but actually has cooled itself to ~1K. --Reuben 21:30, 5 June 2007 (UTC)

You thinking is correct. In the case of an ideal gas, each gas molecule would keep its original kinetic energy as it zips off into space. The process is called adiabatic free expansion. (I note this is currently a requested article. Any volunteers?) The process is adiabatic, in that no heat is transferred to or from the gas, but it is neither reversible nor isentropic: the entropy of the system increases greatly as the gas increases in volume without cooling down. For a real (rather than ideal) gas, interactions between the molecules can cause either cooling or heating to take place; see Joule-Thomson effect. This cooling or heating can be understood as kinetic energy being lost to, or gained from, potential energy, by the gas molecules' pulling or pushing on each other as they move apart. --mglg_(talk) 22:43, 5 June 2007 (UTC)

Eh, no, I don't think that's quite right. It's true that the average kinetic energy of the atoms, in the frame of reference of the original box, remains the same. But it isn't random kinetic energy anymore; some of it is now part of the energy of motion of a clump of gas all moving in one direction. So the gas does in fact become cooler. --Trovatore 06:07, 6 June 2007 (UTC)

I should say that I'm talking about an ideal gas. I looked up the Joule-Thomson thing; my guess is that the experimental setup must not permit the expelled gas to keep moving; that's why the distinction regarding "external work" as opposed to simply "work". The gas does work -- on itself -- when it escapes; it's that work that causes it to go fast, and the gas will cool as a result of doing that work. But if you then stop the gas before measuring its temperature, you change that energy from the energy of motion of a clump of gas (which is not heat) back into heat, and that annuls the cooling due to the work the gas did on itself. In the "outer space" scenario, though, there's nothing to stop the gas -- it just keeps on moving, having done work on itself and therefore cooled off.

This is all a bit off the top of my head, and I'm not a physicist, so I hope I haven't made any embarassing blunders. --Trovatore 07:10, 6 June 2007 (UTC)

Jatropha Energy

Jatropha seems to be the perfect solution for energy use. It is not a food like corn. Why don't more countries produce jatropha energy? It seems like a perfect green energy.

The reason for "corn" ethanol is because corn husks and stalks are currently a waste byproduct in corn production. So, they are (inefficiently) converted into ethanol. In Brazil, it has been demonstrated that sugar cane is far more effective, but it doesn't make use of an existing waste product. That is the point behind corn ethanol - it is an attempt to get rid of the waste. --Kainaw ^(talk) 21:46, 5 June 2007 (UTC)

Kainaw, you are unfortunately mistaken: what is currently referred to as corn ethanol is made from the kernels themselves, not from the husks or stalks [3]. Using the husks and stalks, or other cellulose-containing plant matter, to produce cellulosic ethanol would be a much better idea, but that is not what is being done so far. --mglg_(talk) 23:48, 5 June 2007 (UTC)

Will jatropha survive a Kansas winter (for example)? If not, will it grow fast enough to be planted and harvested annually in areas with a short growing season, as corn does? Sugar cane can't be used in most parts of the world because of its particular growth needs. Farmers and ethanol producers know what they are doing.

The concern about using a food crop to make ethanol is misplaced. If some other (non-food) crop becomes more popular, so farmers will find it more profitable than growing food - and food prices still go up. SteveBaker 02:24, 6 June 2007 (UTC)

General Mills announced cereal price increases today [4], attributed in part to the demand for corm to make ethanol, along with higher energy and transportation costs. Of course, the grain is a tiny part of the cost of a box of cereal, probably far less than the cost of making the cardboard box, or the cost of transporting it to the store from the factory, or the cost of advertising it. Edison 15:28, 6 June 2007 (UTC)

Can there possibly be a cure for cancer?

With the new technological advancements and many pills to alleviate the damage cancer soes, is there an end in sight?

A "cure for cancer" is too general a term: cancer is a term that encompasses hundreds of different diseases that, while they share some commonality in terms of dysfunctional cell regualtion leading to malignant tumors, have widely different etiologies, symptoms, progression patterns, etc. governed by the type of initial DNA errors and the cell types affected.

That said, some cancers already have very high survival rates with effective medical treatments readily available (at least to patients in modern Western nations that catch the disease relatively early). It's certainly plausible that eventually every type of cancer will have highly successful treatment options, but some cancers have far more difficult paths towards a "cure" than others and may be many, many years away from the type of success you're probably asking about. — Scientizzle 22:04, 5 June 2007 (UTC)

You do have to take some of these increased survival rates with a pinch of salt. Many of them are the equivalent of "By catching this 2 years earlier, we've improved life expectancy after diagnosis from 3 years to 5 years!", others can involve catching and removing tumours that would otherwise have lain dormant for years, not causing any problems. Our actual ability to improve the lifespans of people with cancer has not greatly improved for decades. We are making progress, but very slowly. Once something other than cutting the tumour out or basic, indiscriminate chemotherapy turns out to be successful, and goes mainstream, maybe we'll see a big improvement. I like the sound of the various targeted chemos that are being worked on. (Oh, and if you have a New Scientist subscription, you can see I'm not just making this stuff up here "Yet it has been known for 100 years that cancers are generally curable if they can be removed while still in their early stages. When somebody dies of cancer it is usually because it has spread from one site in the body to another, yet over the past 35 years the death rate from most of these metastatic cancers has remained largely unchanged.") Skittle 23:14, 5 June 2007 (UTC)

Definitely not. Cancer is a lifestyle issue, and there's no cure for a malignant lifestyle. Vranak

Sounds like you are blaming the victim. Some cancers just occur, due to random mutations, and are not the result of unprotected sun exposure, radiation exposure, smoking, asbestos exposure, pesticide exposure, or other lifestyle choices. Do not point a finger at a child who is dying of leukemia and say "Malignant lifestyle!" Edison 15:32, 6 June 2007 (UTC)

Sure, but when's the last time you heard a child talk about a 'cure for cancer'? They are not so naive. Vranak

I, too, recoiled at your ridiculous throwaway line, Vranak. To generalize cancer as a "lifestyle issue" is a pretty stupid statement. There exist many examples of cancers (often so-called "childhood cancers") that strike those who haven't even had the opportunity to make the "malignant lifestyle" choices we are all familiar with. Additionally, the cruel reality with cancer is that anyone can get it: a handful of genetic mutations in sensitive segments of the genome (particularly proto-oncogenes and tumor suppressor genes), be those mutations inherited or acquired during one's lifetime, in the right cell type can induce a tumor. Certainly lifestyle choices (smoking, UV exposure, etc.) are associated with cancer because they increase the liklihood of such mutations, but they are not necessary to develop those mutations, nor are they sure to cause them--that is, there is certainly not a 1:1 correlation between the quality of one's lifestyle choices and the liklihood of devloping cancer.

Finally, if you honestly believe "there's no cure for a malignant lifestyle", you could do with a dose of good literature & philosophy... — Scientizzle 15:58, 6 June 2007 (UTC)

You're stretching the definition of 'cure' a little far there. Self-improvement is not a cure per se. Look at the original question. The poster is not asking if there will one day be a book of spiritual enlightenment that will rid man of his woes, he's asking about pills to pop.Vranak

[EC] And cures for various cancers may well be developed into various pills to pop...and "technological advancements" is as broad a brushstroke as medical research can be. Your original response was flippant and unhelpful in regards to that question. A general discussion on the etiology and treatment of cancer seems far more appropriate than reading a negative societal connotation into a 20 word question and replying with terse condemnation. — Scientizzle 16:56, 6 June 2007 (UTC)

What lifestyle are you talking about? Respiration produces free radicals that are dangerous, so of course there can be no cure for lifestyle since life itself is toxic. David D. (Talk) 16:47, 6 June 2007 (UTC)

I just noticed you amended your post to clarify wrt the pill popping. I still don't understand the malignant lifestyle comment. The question relates to either killing cancer cells (could be possible) or drastically reducing chances of getting cancer (also could be possible) with medication. Certainly such a magic pill is not currently available, and maybe never, but that does not mean impossible. The key is to be able to target cancer cells specifically or reduce mutation rates. Both are feasible goals. David D. (Talk) 16:54, 6 June 2007 (UTC)

There's two ways to approach the cancer issue: with the mega-industrial pharmeuctical complex, and preventive measures (lifestyle changes). There's no money to be made in the second, which is why we have our dear friends Scientizzle, David, Edison et al who fiercely defend the first. Vranak

Altering DNA

Is there a way to alter you're skin color, eye color, hair color,or race from altering DNA?

Maybe in a century or two. ---CWY2190^TC 21:57, 5 June 2007 (UTC)

As an adult it may prove difficult, as you'd have to modify the DNA structure of many existing cells. It may be easier to modify such attributes for an embryo. But first scientists would need to identify what characteristics of the DNA produce those attributes, and that will take many years of research. — RJH (talk) 22:18, 5 June 2007 (UTC)

It has been done on fishes, see GloFish and genetically modified organism. --Vsion 05:11, 6 June 2007 (UTC)

I think the OP wants to know whether such modifications can be done after conception. —Tamfang 05:46, 6 June 2007 (UTC)

People of India contrasted to Caucasian

Apart from the lighter skin, variety of eye colors and hair what elese makes them different. What lead to these traits, biotic factors,abiotic factors, people?

Can you briefly explain the history/evolution between these groups of people.

Start by reading about Race, and also try Category:Race. 69.201.182.76 22:15, 5 June 2007 (UTC)

Recently in the ref desk, the topic of lactose intolerance came up. Asians (including India) are more prone to lactose intolerance than Europeans. --Kainaw ^(talk) 23:39, 5 June 2007 (UTC)

Flame temperature increased by electric arc?

See Talk:Brown's gas#To do. According to U.S. patent 4,014,777, oxygen and hydrogen gas can be passed through an electric arc, whereupon they absorb electrical energy from the arc and split into lone atoms. The patent says that when Template:Hydrogen molecules are split into 2Template:Hydrogen, the atoms absorb 101,000 calories per gram mole. Template:Oxygen→2Template:Oxygen absorbs 117,000. (What's the metric equivalent?) On recombination into water, the temperature of the flame produced will then be hotter due to the more energetic particles than if they had not passed through the arc.

Is this legit? — Omegatron 23:16, 5 June 2007 (UTC)

Well, perhaps - very briefly...see Nascent hydrogen. SteveBaker 02:21, 6 June 2007 (UTC)

How do you determine the ka value of a substance

Hi, Omegatron. Calorie says that in scientific use "calorie" means the gram calorie, the amount of energy needed to raise one gram of water one degree C, which 4.184 Joule. There are at least 3 slightly different values for the conversion factor given in the article, depending on temperature. Things that are patented are not always practical, since there is no longer any requirement that a working model be demonstrated. Given that all it takes is a spark to cause the exothermic recombination of H₂ and O₂ into water, it is hard to see how one could take the mixed gases and pass an electric arc through them to split the strong covalent bonds in the H₂ into monotomic Hydrogen and do the same to oxygen, as in Brown's 1977 patent, without immediately producing H₂O. Maybe he found a way. In a different talk page I mentioned a high school chem book "Modern Chemistry" by Charles E. Dull et al, published by Holt Rinehart and Winston, NY 1962, which on page 129-130 described the "atomic hydrogen torch" which passes an arc through the hydrogen before mixing it with the oxygen, using tungsten electrodes, to break down the hydrogen covalent bond. In the diagram, the torch appears to supply only hydrogen to the flame, and achieves a 4000 degree C flame. The monatomic hydrogen appears to burn immediately after it is split. The arc method is attributed to Irving Langmuir(1881-1957). [5] is a website which discusses Brown's gas and HHO and says the Langmuir invention dates to 1926. An H₂ molecule effectively has the s orbital of its K energy level filled, and thus has the stable K shell configuration of a helium atom. The electric arc would have to supply substantial energy to break the bonds in the hydrogen or oxygen, so it would appear to be a process for achieving a high temperature flame at an energy cost, more than a process to get more energy out of the gasses. If oxygen went through its own arc before combining with the separately split hydrogen, it makes sense that a very hot flame should occur as it gives up the energy which had just been added to it by the arc. Edison 16:12, 6 June 2007 (UTC)

June 6

Wrestling

Is wrestling really faked?

It depends really which one you are talking about. The WWE, for example, uses plenty of fake acting, but some of the pain is definitely real. On the other hand, Olympic wrestling is probably not fake. x42bn6 Talk Mess 01:50, 6 June 2007 (UTC)

Yes, it is scripted theater. See the article professional wrestling.

No, wrestling, as an olympic or college sport, is certainly not faked. Yes, "Professional" wrestling, as seen on the WWF, is fake. Read the articles. -- jake. 01:55, 6 June 2007 (UTC)

Olympic/college wrestling isn't faked - but the junk you see on TV most of the time is certainly faked. In fact, there is a school out in Fort Worth, Texas where they teach that stuff. SteveBaker 02:19, 6 June 2007 (UTC)

As I understand it, there's degrees of 'fake' in wrestling. While the result is predetermined for the sake of the storyline and no-one (usually!) goes out there with the intention of hurting his opponent, the actual events of the match itself are not always scripted - depending on the skill of the wrestlers involved. If you're dealing with two guys from a mat wrestling/martial arts background who really know how to fight, a lot of it can be improvised. If the guys who are basically just musclemen are involved, they work it out move-for-move beforehand. Sometimes the punches, kicks and slaps can be real - as can the blood and the pain from submission holds. --Kurt Shaped Box 05:18, 6 June 2007 (UTC)

Imagine if soccer is run the way "professional wrestling" is run. We will have Shaolin Professional Soccer Entertainment (SPSE). Females nuns will disguised themselves as male goal keepers and it would be Kung Fu Galore on the fields of glory!!! 202.168.50.40 04:38, 6 June 2007 (UTC)

Fake is probably a misnomer as applied to pro-wrestling (obviously amateur and Olympic wrestling are no more fake than any other real sport). There's a few quotes that relate to this that I like from Mick Foley, former WWE Champion, New York Times bestselling author, and still sometime participant in the WWE. In his second autobiography (Foley is Good: And The Real World is Faker Than Wrestling) he says:

• On wrestling: “In wrestling, we now readily admit that the fate of the match is predetermined, the action is often choreographed, and the participants are, for the most part, friends.”
• On the action: “We entertain fans around the world by presenting a reasonable facsimile of a real fight while adding athletic elements that could not plausibly happen in the real world. Have you ever seen a “reversal of an Irish whip” in a real fight? Or in the Olympics? How about a moonsault or a Hurricanrana? Or the worm? Highly unlikely.”
• On the 'fakeness': “Whether it be sport or show wrestling is physically demanding work...I have never approved of the word “fake” as it pertains to professional wrestling, because the pain and injuries are very real...”
• And just for good measure, I like this on the infamous chair shots: “Yeah, shots to the head with a steel chair hurt, unless of course you use the popular “fake chair” that many fans know so much about. Personally, I don’t know where to find one, and if such a thing is a reality, I wish someone would have told me a long time ago.”

There's a reason the WWE repeatedly remind fans, especially aimed at kids, not to try it home, and why the participants are highly trained professionals (yes, before becoming a pro they all attend the wrestling schools that SteveBaker scathingly refers to above). Sure the match results are predetermined, but the danger and injuries are very real. Ask any of the former wrestlers living their life out in a wheelchair, e.g., the Dynamite Kid and Darren Drozdov, or with less serious lifelong injuries from the sport, which is pretty much anyone that's done it for any length of time. --jjron 09:35, 6 June 2007 (UTC)

I can confirm that professional wrestling moves can hurt. Yes, I was one of those dumb kids who used to 'try it at home' (or in the schoolyard) when I was 11. This was when Jake the Snake and Hacksaw Jim Duggan were popular in the WWF - my buddies and I were always DDTing each other or braying each other with 2x4s. --Kurt Shaped Box 10:01, 6 June 2007 (UTC)

Is this on the right reference desk? – b_jonas 11:10, 6 June 2007 (UTC)

Read Kayfabe. Corvus cornix 16:43, 6 June 2007 (UTC)

Indian Race

What is the latest theory about Aryans

1. British Raj ended in 1947, yet all discussion of Aryan or Dravidian "races" remains highly controversial in India. It is now widely believed that the British only used this as their 'Divide and rule' blueprint for taking over the region.[17]The British also used this "theory" of perceived differences between so-called "Aryans" and "Dravidians" to propagate racist beliefs concerning the inherent "inferiority" of Dravidians compared "Aryans", thus justifying their colonization of South Asia (since the British identified themselves as "Aryans")

or

The Aryan race was a term used in the early 20th century by European racial theorists who believed strongly in the division of humanity into biologically distinct races with differing characteristics. Such writers believed that the Proto-Indo-Europeans constituted a specific race that had expanded across Europe, Iran and India. This meaning was, and still is, common in theories of racial superiority which were embraced by Nazi Germany. This usage tends to merge the Sanskrit meaning of "noble" or "elevated" with the idea of distinctive behavioral and ancestral ethnicity marked by language distribution. In this interpretation, the Aryan Race is both the highest representative of mankind and the purest descendent of the Proto-Indo-European population.

Could clear this up? I am doing a paper on the people's of India and it is very interesting.

My main question is: What is the connection and difference of dravids and aryans?

Have you taken a look that the Aryan article? "Aryan"s (nowadays) refers to proto Indo-Iranians, essentially originating from Eastern Asia, and therefore much, much closer to modern Indians than British. - jake. 01:47, 6 June 2007 (UTC)

Were early indians white

Were they? because they are classified as caucasian

Are you talking about native americans or persons from India? You appear to be confusing skin color with race. Caucasoid does not mean white. --Tbeatty 05:47, 6 June 2007 (UTC)

Dravidians were in India before the Aryans (speakers of languages related to Hindi and, more distantly, to most of the languages of Europe) invaded, so I'd say no, early Indians were dark. —Tamfang 05:49, 6 June 2007 (UTC)

Christmas tree lights

I have several strings of christmas tree lights on my porch. Last week I had two. The second string (attached to the end of the first) had been going out in sections. Finally the entire string went out. I assumed that there was a break somewhere early in the cord. However, my girlfriend bought a new string and, unthinkingly, attached it to the end of the second line. To my surprise, the new string (the third in the line) lit up! So there was some current going throught the string, but not a single light was on. Sure, each and every one of them could be broken, but is that likely? What's the most likely situation in which this can occur?

Thanks! jake.

I think the strings work in parallel so that one string doesn't affect the other but within the strings it may work in both parallel and series (strings of 10 as series and connected to each other in parallel?) if it goes out by sections. You could use a multimeter and measure the resistance across half of the string, if the circuit's open the divide that part in half and measure again, and repeat until you have found out where the light bulbs are burnt out. Also consider buying LED ones as they are practically invincible. --antilived^{T | C | G} 08:04, 6 June 2007 (UTC)

With the old minilights, the only hope you had was that only one would burn out 'properly', meaning that it would go off, but the rest of the lights would stay on. You had to replace it right away. Once more lights burned out, and if one light had a problem with the connection, then it became impossible to bring it back to life (even after a long effort!!!). I finally threw out the damn things and went with LED. --Zeizmic 11:32, 6 June 2007 (UTC)

See our articles about antifuses and Christmas lights. In any case, miniature Christmas lights are a combination of series and parallel circuits; nowadays, in the 120 volt United States, they mostly seem to be zones of 50 miniature 2.5 volt lamps connected in series so the entire zone operates on 120 volts. If the overall string is, say, 100 lamps, there will be two individual series zones. If the overall string is instead an "icicle" string with 300 lamps, there will be six individual zones.

A single lamp failing will cause the entire zone to go out (while the rest of the zones in the string stay lit) but the antifuse contained in the failed lamp will usually "blow", bringing the other 49 lamps in that zone back into operation again. If more than one failure occurs simultaneously while the string is unpowered (perhaps you dropped the string and mechanical shock broke several filaments), there may not be enough voltage (later) on any given antifuse to blow it and that zone will stay out; that's one reason why prompt replacement of dead lamps is essential. (The other reason is that with 49 lamps sharing the voltage intended for 50 lamps, they're all overloaded slightly. And when the next lamp blows, 48 lamps are sharing the voltage. Then 47, then 46, and soon lamps are burning out very rapidly.)

Sometimes, you can bring a failed zone back into operation by tapping every lamp in the zone while the power is on. The mechanical vibration will help blow the antifuse in the failed lamp. Sometimes, you can carefully inspect every lamp in the zone and see the failed filament. Sometimes, you can take a known good lamp and "walk" it through every socket in the failed zone. (Unseating and reseating the lamps sometimes fixes the problem as well if it's only "connectoritis".) Sometimes, the only way to get things working is to use a test light or voltmeter on the energized string, but if you don't know how to do this safely, you can electrocute yourself!

Atlant 12:33, 6 June 2007 (UTC)

If only I had a Porche… I could live with the christmas lights. —Bromskloss 15:13, 6 June 2007 (UTC)

If there were 50 lights in a string, and one failed and shorted out internally, the others would remain on with 2% overvoltage, resulting in brighter and more efficient operation, but with reduced lifetime. When one has aged out, the others are also approaching end of life, so soon another fails (and bypasses itself). Now the remaining ones have 4.2% overvoltage etc. The remaining bulb continue to fail, and after 5 have failed they remaining ones are at 11% overvoltage. A bulb rule of thumb is that 10% overvoltage cuts the lifetime in half. They should go faster and faster, with the last bulb seeing 120 volts applied to a 2.5 volt filament, causing it to go off with a flash. The overcurrent might be sufficient to blow the series fuse for the string before it got that far. Edison 16:23, 6 June 2007 (UTC)

Any theories of an early global religion?

Question moved to Wikipedia:Reference_desk/Humanities#Any_theories_of_an_early_global_religion.3F 83.79.167.221 15:22, 6 June 2007 (UTC)

Modafinil and Bupropion

I want to suggest to my psychiatrist to prescribe me modafinil along with the bupropion I currently take. Does anyone know if modafinil has any sexual side effects? The sexual side effect of bupropion is increased libido for me (which is great!) however I do not want to decrease it with another med.. --Juliet 13:42, 6 June 2007 (UTC)

Please review the How to ask a question header at the top of this page. The eighth bullet point reads:

• "Do not request medical or legal advice. Ask a doctor or lawyer instead."

If our article on modafinil doesn't have the information that you require then you should ask a doctor. hydnjo talk 15:45, 6 June 2007 (UTC)

gravitomagnetic acceleration ???

http://www.arxiv.org/ftp/gr-qc/0610015 This article claims that if these fields exist they could make an accelaration gravitomagnetic field, is that a term for small particle behaviour or actually a way of propelling matter [ could be used for transport, propulsion] Sorry for my ignorance. Robin

Brightest object that we can see in our night sky?

Recently i read this... When viewed from Earth, Jupiter can reach an apparent magnitude of -2.8, making it the fourth brightest object in the night sky. And was wondering what number one two and three were? because i once eons ago read an article stating that the brightest thing in our night sky was the iss, international space station.

How about the Moon, Venus, and Mercury. See those articles for their apparent brightness.--Shantavira|^{feed me} 16:58, 6 June 2007 (UTC)