Wikipedia:Reference desk/Archives/Science/2006 September 18

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September 18

Future of plant genetic engineering

What do you think is the future of plant genetic engineering? I've read things about the dangers of GM crops, such as golden rice that has become prevalent in china, and a type of corn made by a company called epicyte that can be used as a contraceptive. What are some active GM plants out there, and does anyone know any GM horror stories (or potential GM horror stories?) Thanks! Dave 130.207.180.27 00:28, 18 September 2006 (UTC)

You seem to be looking for horror stories and totally look over the tearing greatness that genetic engineering has brought us. Aside from the fact that the "unscientific" genetic engineering that brought us apples, and oranges, pumpkins, and cabbage, detoxified almonds (they used to have a compound that when digested produced 10x the lethal dose of cyanide for an adult), genetic engineering is possibly the greatest technology that has ever evolved from the human race. Read a bit on Norman Borlaug, easily one of the greatest people who ever lived, credited with saving billions of lives through genetic engineering. It is easy to complain and talk about the bad things, when you know you have at least one meal per day, and are not among the 25,000 to die of starvation everyday. Also, what is wrong with the golden rice, that is to help with the problem of VAD? — [Mac Davis](talk) (New! SUPERDESK|Help me improve)02:43, 18 September 2006 (UTC)

Mac Davis, genetic engineering has a specific meaning. Please do not confuse it with plant breeding or artificial selection — which are NOT genetic engineering by any stretch of the imagination. Norman Borlaug, although a proponant of GMO, worked largely on HYV hybrid varieties without the use of genetic engineering techniques. The other benefits you talk of are not from genetic engineering but from ordinary plant breeding. To say we should turn a blind eye to the problems of genetic engineering because of the benefits is plain stupidity. —Pengo ^{talk · contribs} 03:00, 18 September 2006 (UTC)

Sorry, how embarressing. I was referring to the GM crops, obviously. However, I do believe that purposefully altering the genes of a plant make plant breeding a subset of genetic engineering. — [Mac Davis](talk) (New! SUPERDESK|Help me improve)03:15, 18 September 2006 (UTC)

One "horror story" is that of the weed Lactuca serriola, which gained herbicide resistance from being contaminated by GMO lettuce. It's not that much of a horror story really. Another is of some GMO corn produced in the US (See Bt_corn#The_StarLink_corn_controversy). There are probably not many real horror stories relating directly to GMOs. The key issues, in my mind, is that of the patenting of life (biopiracy); the loss of genetic diversity (countered partially by seed banks and seed exchange groups and networks); and the placing of a large amount of trust in seed corporations, which farmers have become reliant on as they cannot replant their own seed. These issues are the same for hybrid varieties as much as they are for GMO, and are not safety issues as much as they are food security issues. —Pengo ^{talk · contribs} 03:14, 18 September 2006 (UTC)

Biopiracy will surely be a fiery issue when it gets in the forefront. That is going to be scary, and probably in my lifetime. Yikes!! — [Mac Davis](talk) (New! SUPERDESK|Help me improve)03:21, 18 September 2006 (UTC)

If you don't want it to occur within your lifetime, I suggest you take up smoking. :-) StuRat 06:34, 18 September 2006 (UTC)

Can't you think of any slower ways to die? DirkvdM 18:57, 18 September 2006 (UTC)

The potential of any GM plant spreading worldwide without any ability to stop it is indeed frightening. Even if grown in a greenhouse, preventing workers from taking out pollen on their bodies or clothes or carrying a seed in the tread of their shoes is nearly impossible. Such crops would need to be given the highest levels of biocontainment treatment, similar to how anthrax and bubonic plague are treated in research labs, to prevent dispersal. Such treatment would make GM foods completely impractical. StuRat 06:42, 18 September 2006 (UTC)

The potential could be good or bad. If it were doing more harm than good (who could be the judge of that?), than that would be "bad." But if it was a vitimin-rich protein-packed, high calorie crop, that didn't kill off too many species (who could be the judge of that?), than that would be "good." — [Mac Davis](talk) (New! SUPERDESK|Help me improve)15:22, 18 September 2006 (UTC)

I agree that most GM modifications are beneficial, but the potential for such GM plants to spread uncontrollably is still troubling. This can lead to wiping out non-GM varieties, thus forcing people to consume the GM variety, against their will. If some negative side effect is later found in the GM variety, it may be difficult to get the original variety back. Perhaps an "assassin virus" would then need to be programmed to go after the GM variety to wipe it out in the wild. StuRat 16:45, 18 September 2006 (UTC)

I have a cure for this problem, from the movie Jurassic Park. In that movie, the "lysine contingency" refers to the fact that the cloned dinosaurs were genetically engineered to lack the normal ability to synthesize lysine, a critical amino acid. While captive, these animals would be provided with lysine in their diets. If they escaped, however, they would die in short order from a lysine deficiency. Similarly, some defect (perhaps multiple defects) should be programmed into the GM plants, so that escaped varieties would die naturally. Legislation should be passed making such protections mandatory, preferably at the worldwide level. StuRat 16:59, 18 September 2006 (UTC)

Most GM plants are prisoners of their poor design. Built to resist one and only one species of insect or fungus, they are more able to get attacked by another pest, or by any mutation of the original ones : what do you think happened before in South America : people bought GM seeds, their plants were soon attacked and the people are poorer. Now when you buy stocks of GM engineering companies, you get rich. Right ? See also [1] -- DLL ^{.. T} 18:28, 18 September 2006 (UTC)

The problem is we know so little of what we're doing in that field that we don't even know what the horror stories might be. If you do something bad you can usually rectify it with equal effort. But some things propagate themselves in a feedback loop. And life is the greatest expert at feedback. Once something starts it can be unstoppable, spreading exponentially. That's why we still haven't managed to exterminate loads of diseases - miss one bacterium and in a few years it will be all over the place again. And if we inadvertently create some disease (or something that creates a disease or gives it a breeding ground to evolve or something I can't think of (!)) then that can be as hard to stop as malaria. Of course I'm talking about plant diseases here. And if farmers the world over would switch to certain plants because they give a much bigger yield then that will reduce biodiversity, nature's best counterforce against the spread of diseases, because some varieties might not be affected and thus take the place of the ones that died - the same mechanism that diseases use to become resistant to antibiotics. Life is a constant battle between species and the ones with the greatest biodiversity stand the best chances of survival.

As an illustration think of what has happened with the introduction of species to new environments (rabbits in Australia, that sort of thing). Most will not survive in the wild, but the ones that do won't have any natural enemies and will spread like wildfire. And with gm we may create species that don't even come close to what life on Earth has seen so far. Maybe not yet, but if we continue we'll get there for sure. DirkvdM 18:57, 18 September 2006 (UTC)

I think there may be a misinterpretation here about GM plants. They aren't completely new plants engineered from scratch, but more typically very close to an existing plant, with perhaps one gene added to provide disease resistance, produce a valued nutrient, etc. Therefore, they retain all other characteristics of the original plant, such as resistance to all the same diseases as the original. However, if the new, more disease resistant plant becomes widespread, this will put pressure on the disease causing organisms to evolve a counterattack. The original plants will be particularly susceptible to these new "super bugs". StuRat 19:11, 18 September 2006 (UTC)

Yeah, I know, I was just taking it a little further. GM is sort of evolution on steroids. So if it becomes popular, a new species may be created in a much shorter time. And if that is taken further still, we might create something that would normally never have evolved (on Earth), something that not only has no natural enemies in one spot, but anywhere on Earth, so we couldn't even introduce one. Of course we could fabricate one, and that will lead to a 'natural' selection of who is the cleverest GM engineer. Of course this could also be used for warfare, so we had better start with it real quick before 'the enemy' beats us to it (who is it this time? Oh yeah, terrorists). DirkvdM 06:27, 19 September 2006 (UTC)

Turpentine

I went to the article on turpentine looking for some sort of confirmation of the story that the stuff can enter through your skin and stays in your blood (or collects in your ankles) and never leaves your body.

A. Is this true? Or where does this idea originate?

However, looking at the article, I discovered that Wood turpentine and Mineral turpentine are different things, and looking at the shelf of my local hardware store, I notice that there is also Mineral turpentine substitute which is different again from mineral turps. (The article seems to confuse the two — which is partially my fault).

B. What's the difference between these substances?

C. And does anyone feel like sorting out the articles to reflect these differences?

—Pengo ^{talk · contribs} 02:39, 18 September 2006 (UTC)

I looked around and didn't find this particular myth, but if it exists, it probably comes from painters and their practice of mixing turpentine with all sorts of nasties, such as lead. --Zeizmic 12:08, 18 September 2006 (UTC)

Mineral turpentine substitute just sounds to me like a sloppy way of saying "mineral turpentine (substitute for wood turpentine)". I can't think of many instances in life where I've needed a substitute for a substitute. Well there was this one time in grade 5...  freshofftheufoΓΛĿЌ  14:27, 18 September 2006 (UTC)

The labels of the two seemed to have different ingredients, but i only glanced. There's also "low odor turpentine" which may or may not be the same as any of the above. —Pengo ^{talk · contribs} 09:04, 19 September 2006 (UTC)

Metals, non-metals, and semi-metals

Looking at the Periodic table, it's pretty clear which elements are considered metals, non-metals, and transition metals. After all, there's a big old streak running from Boron to Polonium. What I'm not entirely clear on is why, that is, why those guys on the top like covalent bonds and the guys on the bottom like metalic bonds. At first I thought that it could be electronegativity -- maybe the higher electronegativities would favor covalent bonds because in covalent bonds, the electrons are more localized -- but a quick look down one of the columns refutes this.

My next thought was that as you go down a column, the atom gets larger and larger and has more and more complex valence shells -- maybe the fact that the shells are held further away from the nucleus allows the electrons to be shared more easily amongst all the nuclei (leading to a metalic bond), and maybe as these shells get more full, this has less of an effect (an attenmpt to explain why lead is metalic while polonium is not). This explanation seemed plausible, but not great.

Any ideas?

for a start...i think Polonium is sort of metallic, or at least metalloid. I don't think it's a non-metal.

But Polonium would be less metallic than lead. this is because lead is physically smaller than Polonium. Polonium has two more protons than lead, and two more electrons. The two extra protons make the nucleus stronger. However, the two extra electrons go into the same shell...meaning Polonium has the same number of shells as lead.

This means in Polonium, there is a stronger nucleus holding on to the same number of shells of electrons. This means the outer shell of Polonium is held more tightly than the other shell of lead...hence Polonium would be less inclined than lead to shed off its valence shell electrons (which is what metallic bonding involves.)

may i suggest you read the articles here on Metals and Periodic_tableYaksha 07:20, 18 September 2006 (UTC)

Classification as metal/semiconductor/insulator is based on band gap and valence band. The effect is primarily one of delocalized bonds and their energy spectra. The physics of electronic band structure is not simple. In metals, the conduction band has no gap separating it from the valence band, so electrons may be promoted from a localized orbital (essentially attached to a single nucleus) to a delocalized orbital (essentially smeared out over a large volume). In semiconductors, valence electrons may be promoted to the conduction band by providing a small energy, for instance thermal energy at room temperature. Insulators have such a large bandgap that essentially no electrons are in the conduction band at room temperature. -- Fuzzyeric 14:06, 18 September 2006 (UTC)

distinguish between network bridge,repeaters,routers,ethernet hub,bluetooth and gateways?

i need the answer of dis question in proper format. please help me with this

What's great is you don't even try to disguise this as something other than a homework question. Benbread 10:43, 18 September 2006 (UTC)

Read the articles. o_o --Proficient 05:48, 19 September 2006 (UTC)

Questions about allergies

Answered

I was diagnosed with an allergy to penicillin (and another drug, sulfa) at a young age. My father recently suggested that the diagnosis might have been wrong, and that I should get tested again, because penicillin is such a useful drug and so on. Is it likely that it could have been misdiagnosed? (He claims that the doctor seemed rushed and "unprofessional".) Alternatively, is it possible to "grow out" of such an allergy? Would re-testing be worthwhile?

Second, my boyfriend is allergic to most seafood (with exceptions for some processed fish, like canned tuna) and some nuts (allergic to almonds, brazil nuts, and walnuts, but not pistachios, peanuts, macadamia nuts or cashews). Do you see any connection between these allergies? Fish and nuts are said to have high levels of omega-3 fatty acids. Is it possible that that's the allergen? If so, is he in danger of not getting enough omega-3? What sort of factors would cause him to be allergic to some nuts, and some fish, but not others?

Thanks in advance! --Grace 07:12, 18 September 2006 (UTC)

I agree that you should be retested, as allergies do change with age, and the doctor might have misinterpreted the results originally. StuRat 10:06, 18 September 2006 (UTC)

Reactions to substances vary and not all are "allergic". Reactions which indicate an allergy with a high degree of certainty include hives and swelling of mouth or throat, especially with a change of voice or narrowing of the larynx. The likelihood of a similar or worse reaction upon next exposure is fairly high. At the opposite end of the spectrum in terms of risk is a vague red rash which is a common part of many viral infections and which is sometimes amplified by concurrent use of ampicillin. The problem with labelling someone penicillin-allergic is that the penalties for being wrong in either direction are so asymmetric. If someone is erroneously told she is allergic to penicillin, there is rarely any penalty for avoiding it and lots of people react positively to their "specialness". If someone is erroneously told she is not allergic to penicillin and is prescribed it in the future she could develop a worse reaction with throat swelling and very rapid death. This severe reaction is called anaphylaxis and doctors consider contributing to someone's avoidable death a Bad Thing. So this enormous asymmetry of consequences leads to many people being labeled penicillin allergic erroneously. This is well-recognized by doctors and there are published guidelines for deciding how likely it is that a person is really allergic based on the nature of the original reaction (not based on the parent's estimate of the "professionalness" of the doctor). The major disadvantage of being erroneously labeled penicillin-allergic is that you get prescribed more expensive antibiotics which migh incur other risks. There are ways to test for penicillin exposure with small risk if someone needs treatment and no alternative antibiotic seems appropriate. Why not have this conversation with your doctor?

As for your second question, allergies seem to be formed primarily against specific proteins in foods rather than against omega-3-fatty acids, so your boyfriend has many other possible sources of the fatty acids. We have no idea why people become allergic to certain food proteins and not others-- be glad it is limited. Best wishes. alteripse 10:33, 18 September 2006 (UTC)

Your boyfriend is allergic to some of the most common food allergens. Besides tree nuts, fish, and shellfish, the other most common food allergens are peanuts, soy, milk, eggs, and wheat. I sympathize, having certain shellfish allergies myself. One of the hardest things about it is explaining it to restaurant staff. You would think they would hear it all the time, but they are frequently rather stupid about it, either not understanding the concept of a food allergy or acting "put out" that you ask for special non-deadly food. --Ginkgo100 ^{talk · e@} 04:34, 19 September 2006 (UTC)

Thanks all, very helpful! -Grace, not logged in

Fishy coincidence

Take two rivers not too far away from each other, say you consider the Po and the Rhône River, which both give water to the Mediterranean Sea. You have a look at what fishes live in these two rivers, and say you discover that the carp lives in both rivers. Question: how is this possible? With the exception of salmons, no fish can live both in fresh water and in the sea (I am not sure if NO fish can, but of course SOME fish cannot). So how is it that two rivers which are not connected by some fresh water channel contain the same species of fish? Of course this does not depend on Man. I have asked a biologist friend, but her answer does not really satisfy me, so I am posting it here. And I will tell you what her answer was, but I would like to see some other opinion first. Cthulhu.mythos 08:55, 18 September 2006 (UTC)

Well for the example you give, the Alps are only ~15 million years old, so the freshwater fish could have been part of a connected watershed earlier than that. Though I haven't checked on carp in particular, most fish families are far older (100s of millions of years), so it wouldn't be surprising to find carp on both sides. After ~15 million years though, you'd expect to see a variety of descendant species unique to each side as well as a few ancestral species that survived in both places. Dragons flight 09:22, 18 September 2006 (UTC)

I agree. The two rivers may have had a confluence at some point in the past, such that one was a tributary of the other. I suppose that, if it can be established that the same species existed in both rivers prior to development of boats by people, this would even constitute evidence that the two bodies of water were, indeed, once connected. StuRat 10:02, 18 September 2006 (UTC)

Mmmmh. I see. Now I will tell my friend's answer. She said: well, once upon a time during Pangea, or anyway durind a time when the two rivers were somehow connected, there was the carp's great-great-great-granmother, which was not yet a carp. Then continents drifted and blah blah and the two rivers became separated. So we have two ancient rivers with the same archeofish. As the two rivers wetre once connected, they cannot be too much far away, hence the climate must have been about the same in the two rivers, hence the two archeocarps will undergo the same evolutionary processes, as they live in very similar environments. What you get is the same carp in the two rivers.

Looks like we need an article on fish falls.--Shantavira 11:02, 18 September 2006 (UTC)

Now what does not satisfy me is that I do not believe that the same evolutionary processes must happen, of course the two great-great-great-granchildren will be similar species, but I see no reason for them to be the very same species (interfecundity, in perticular). Then what she replied was: they will just like two different races of carp, not really the same carp but very very similar, like "Caucasian" and "Asian" for Man. Cthulhu.mythos 10:24, 18 September 2006 (UTC)

What your friend describes is called convergent evolution, and does happen, but I don't know if it happens with fish. Morwen - Talk 11:09, 18 September 2006 (UTC)

No, it's parallel evolution. I agree that there is a logic flaw in what the teacher said, though. While parallel evolution can produce similar traits from a single proto-species in similar environments, it never produces exactly the same species. StuRat 11:12, 18 September 2006 (UTC)

Agree, especially if you're talking about a length of time like that since Pangaea. In cases like this there are often more simple explanations that are easily overlooked, e.g., major and rare floods allowing the rivers to be temporarily connected, rising and falling sea levels, coming and going of ice ages, etc. Whether these can necessarily explain this specific example I don't know, but they do explain a lot of similar cases. While these things may be rare or a long time ago on our time scale, in geological and evolutionary terms they are not - a once-in-a-thousand-years flood is actually pretty common, and the last ice age at about 10,000 years ago was a mere eye-blink ago. --jjron 13:46, 18 September 2006 (UTC)

Why does evolution or connection have to be involved? What about the possibility of a visitor from Po to the Rhone becoming interested in the carp, and then bringing a few back with him to place in the Po? Man could have easily accomplished this thousands of years ago. - Rainwarrior 15:54, 18 September 2006 (UTC)

I believe the original question was asking for reasons that didn't involve human interference. Of course human involvement is a possibility in a case like this, but if there was evidence that the fish were in both rivers prior to human occupation of the region then there would have to be a natural cause. --jjron 16:19, 18 September 2006 (UTC)

Freshwater systems used to be a huge source of diversity, and endemism was common within them. However, man has basically destroyed the fresh water systems of the world, and most are overrun by introduced species which outcompete native species. Naturally, crossing to different river systems occurs through large flooding (which can occur to a huge scale, but is rare), and previously connected rivers. Remember that rivers are constantly changing, and can split apart, merge, or whatever. They are rapidly changing, much faster than continental change. --liquidGhoul 16:30, 18 September 2006 (UTC)

It is still possible to see man as the origin of a plain identity of carps in both rivers. They belonged to the same empire during centuries, and you may carry freshwater fish a long time in a bucket. I'm thinking of a Roman war veteran who was allowed some part of Provence and wanted to fish his old Po carps to have his foreign wife accomodate them in the Po valley fashion. -- DLL ^{.. T} 18:38, 18 September 2006 (UTC)

Arowanas are obligatory freshwater fish; they cannot tolerate sea water, yet they are found on different islands and continents around the world. They evolved long ago, when the landmasses were connected, and were carried along when the continents and islands broke apart.[2] Cutthroat trout, an American species, diverged into numerous subspecies, each peculiar to a separate river basin, more recently. During the Ice Age, their ancestor was able to travel "over the mountains" into different rivers.[3] By the way, many other fish, such as the barramundi perch, can tolerate both fresh and salt water. See fish migration. Of course, the carp themselves could be introduced species, not natives. --Ginkgo100 ^{talk · e@} 20:09, 18 September 2006 (UTC)

Flies

I read the article on here about flies. I was wondering if anywhere in the article does it say if they go to the bathroom at all? I'm just curious about this.

Sure they do. The insect article is probably better than the fly article for this, especially the Morphology and development section. They have a digestive system ending in an anus, and an excretory system (read about Malpighian tubules for this). --jjron 14:07, 18 September 2006 (UTC)

Flies do not have a designated area where they go to excrete. Therefore, no bathroom. — [Mac Davis](talk) (New! SUPERDESK|Help me improve)16:17, 18 September 2006 (UTC)

I find them in my bathroom often enough, so I reckon they do ;) --jjron 16:25, 18 September 2006 (UTC)

They go to the toilet less often if you keep it clean.Edison 16:58, 18 September 2006 (UTC)

Or is the question if flies ever bathe? They use their own saliva for that, don't they? (Or was that dogs?) DirkvdM 19:08, 18 September 2006 (UTC)

What do you think flyspecks are? alteripse 23:28, 18 September 2006 (UTC)

Things for correcting their bad eyesight? 8-)--Light current 23:36, 18 September 2006 (UTC)

indium oxide

Hello everyone,
does anybody knows the thermal conductivity of indium (III) oxide around room temperature ? I already searched in a few scientific databases and handbooks without results... Thank you ! David Berardan 11:56, 18 September 2006 (UTC)

[[4]] is our page on it--Light current 22:01, 18 September 2006 (UTC)

Thanks, but I already read that page :-) ... and it didn't give me the answear :-( David Berardan 07:51, 19 September 2006 (UTC)

I know it doesnt have the answer, I was just saying that is our page on it. Google search also negative. Sorry. Can you measure it? thermal conductivity--Light current 08:01, 19 September 2006 (UTC)

I imagine I will have too ^^. I am just a bit impatient, cause my thermal conductivity measurement device is currently broken down ! When I can measure it I will complete the article (but In2O3 being very hard to densify, it probably won't be a very precise value). David Berardan 19:49, 19 September 2006 (UTC)

Well, an approx value (if published in a reliable source WP:RS) is better than no value I suppose.8-)--Light current 20:48, 19 September 2006 (UTC)

spot goo

how come if i squeeze a spot sometimes it just goes pff like a wet fart and sometimes it goes pop and i have to clean the mirror?

Hmm interesting question. Could be to do with the excess pressure built up inside.--Light current 14:24, 18 September 2006 (UTC)

Are you talking about squeezing a pimple ? I understand how they would be filled with puss, as this is left over from your skin fighting the small bacterial infection which caused the pimple. I'm not sure why their would be air inside a pimple, as seems to be described, as well. StuRat 16:32, 18 September 2006 (UTC)

Puss is a cat. Pus comes in zits.Edison 16:58, 18 September 2006 (UTC)

Here pus pus. Doesn't it depend on the size of the zit? And probably the strength of the skin.--Shantavira 17:08, 18 September 2006 (UTC)

I can't believe I've put any thought into this at all, but I'd guess that there are two factors coming into play here: one would be the size of the pimple (or specifically the amount of pus that is trapped) and the second would be the hardness of the plug that has formed at the surface. If the material blocking the pore has hardened significantly, it will not be easily dislodged. Exerting additional pressure when squeezning the pimple might cause it to pop, with the result that the additional pressure also causes the pus to shoot out with more velocity. --LarryMac 19:18, 18 September 2006 (UTC)

A bit like opening Champagne bottles (though attempting pimple sabrage would be ill advised). Rockpocket 04:50, 19 September 2006 (UTC)

For a good example of zit explosions on film, be sure to watch Kevin and Perry go large (a spin off from Harry Enfield's TV show). The scene is where the two girls (Candice and Gemma) whom Kevin and Perry pick up are getting ready to go out and doing their faces. Disgusting!--Light current 14:57, 28 September 2006 (UTC)

Oh its spelled like this on WP: Kevin_&_Perry_Go_Large--Light current 14:59, 28 September 2006 (UTC)

SOLAR PANEL PROJECT

HOW DO WE MAKE A HOME MADE SOLAR PANEL ?

THIS IS FOR A GRADE 5 PROJECT.

PLEASE REPLY URGENTLY §

Here's a link with some information you might find helpful. And turn off the caps lock please, it is impolite. It's like you're yelling.

http://scitoys.com/scitoys/scitoys/echem/echem2.html

Gary 14:03, 18 September 2006 (UTC)

You forgot to reply urgently!  freshofftheufoΓΛĿЌ  14:07, 18 September 2006 (UTC)

XD --Proficient 06:28, 21 September 2006 (UTC)

egg drop

What is the best egg drop design that you know of?67.177.19.69 13:03, 18 September 2006 (UTC)mule

The article on egg drop competitions says that commonly used materials include sand and styrofoam. I'm sure there's more than one way to do this, though. Gary 14:09, 18 September 2006 (UTC)

Parachutes are always more fun, though. StuRat 16:15, 18 September 2006 (UTC)

A chicken? DirkvdM 19:14, 18 September 2006 (UTC)

Aerogel, if you've got a particularly well-equipped egg dropping club.  freshofftheufoΓΛĿЌ  03:42, 19 September 2006 (UTC)

Aerogel is harder than polystyrene or sand isn't it? — [Mac Davis](talk) (SUPERDESK|Help me improve)04:01, 19 September 2006 (UTC)

You may be right, some types may be. Carbon aerogel is supposed to be extremely elastic though.  freshofftheufoΓΛĿЌ  06:38, 19 September 2006 (UTC)

Some vacugels are lighter than air. (Vacugel: very experimental aerogel, sintered under vacuum and then hermetically sealed.) Sea also SEAgel. -- Fuzzyeric 01:45, 20 September 2006 (UTC)

I'm very good at this. What you want to do is first isolate and prtect the egg by putting it in a styrofoam cup and packing it with cotton balls making sure to position the egg vertically. Then put this is a coffee can and pack the inside of the can around the egg-cup with crumpled up paper, making sure that the egg-cup cannot move around inside the coffee can. Then, on whichever end of the coffee can you want facing down, put a paper bowl on the bottom with the bottom part of the bowl facing down. Pack the empty space with more crumpled up paper (loose leaf paper works well). After this, duct tape popsicle sticks onto the coffee can facing down, these will break off and absorb some shock. Finally, to make sure your device falls straight, attacht a string to the top of the device and tie lond bits of paper or playing cards. That will stabilize it as it falls, making sure that the end with all of your crumple zones hits the ground. Two more helpfull hints, put your egg in a sealed plastic bag so if it does break, it won't get egg all over your device. The second is that parachutes are notoriously difficult to make work properly. I've only seen one person successfully pull off a parachute retarded egg drop. Deltacom1515 01:50, 23 September 2006 (UTC)

Does this not explain it? — Michael J 16:15, 23 September 2006 (UTC)

Speech to text conversion

I could not find any article related to speech to text conversion under speech processing.

There is a link in the Speech processing article that leads directly to Speech recognition. --LarryMac 13:36, 18 September 2006 (UTC)

ID Card size

What is the logic behind such an odd size od Id-1 cards that have a size of 85.6x53.98mm?

1. Where did you get those numbers?
2. Maybe the dimensions originated in inches. 85.7 mm is 3 3/8 inches, and 53.98 mm is 2 1/8 inches. --Smack (talk) 17:15, 18 September 2006 (UTC)

• It's an ISO standard size for ID cards!

ISO/IEC 7810:2003 specifies:

    * four different sizes of identification cards with a nominal 
      thickness of 0,76 mm and dimensions of:
          o ID-000 25 mm x 15 mm,
          o ID-1 85,60 mm x 53,98 mm,
          o ID-2 105 mm x 74 mm,
          o ID-3 125 mm x 88 mm;
    * the conditions for conformance;
    * the dimensions and tolerances of the identification cards;
    * the construction and materials of the identification cards; and
    * the physical characteristics of the cards such as bending stiffness, 
      flammability, toxicity, resistance to chemicals, dimensional stability, 
      adhesion or blocking, warpage, resistance to heat, surface distortions, 
      and contamination.

ISO/IEC 7810:2003, together with a standard for test methods, provides
for interchange between various types of identification card
processing devices and systems.

No idea just why these numbers, though! --jpgordon^∇∆∇∆ 21:12, 18 September 2006 (UTC)

I'm sure that the logic behind those numbers is "that's the size almost all ID cards were when they officially wrote up the standard". Credit cards and ID cards and whatnot have been essentially standardized for decades, and everything from wallets to card readers to the little static-proof ATM card sleeves all assumed the sizes would stay that size. This is kind of a cop-out answer, but it would take a lot of research to figure out who used that size first and how it became a widespread standard. I wouldn't be too surprised if it was the first social security cards or some such. -- Plutortalkcontribs 13:54, 19 September 2006 (UTC)

Especially the senseless precision – 53,98 mm instead of 54 mm, a difference of 20 µm and less than 0.04% – is curious. Assuming a modest variation in the measured heights of existing ID cards, on the order of 1 mm, would require averaging over several thousands of measurements before the estimated average gets a precision anywhere near that. While very close to 2⅛ inch (= 53,975 mm), the width 85,60 mm is clearly less than 3⅜ inch (= 85,725 mm). If we stick to powers of two for the denominators, it could be 3451/1024 inch in mm, rounded to two decimals, but no lesser power will do. --Lambiam^Talk 20:50, 19 September 2006 (UTC)

Hot and Cold as Sensations...

Has there been any research done as to how exactly the sensations of hot and cold manifest themselves? Clearly, with sufficient exposure, either can be quite painful. Yet the sensations are vastly different. Something that is hot is, well, a burning sensation. And something that is overly cold is a kind of biting sensation. Why is this? There must be some explanation on both a cellular and neurological level. After searching for a bit, I still wasn't able to find the answers I was looking for. Maybe you guys can help. Thanks. - R_Lee_E (talk, contribs) 16:36, 18 September 2006 (UTC)

See this archive. — [Mac Davis](talk) (SUPERDESK|Help me improve)18:08, 18 September 2006 (UTC)

Ah...you beat me to it Mac. --Russoc4 18:12, 18 September 2006 (UTC)

Ah. This helps. Thank you much. - R_Lee_E (talk, contribs) 21:45, 18 September 2006 (UTC)

The archive doesn't answer why we perceive the feeling of hot and cold as we do (i.e. burning vs biting). That is an interesting question and more to do with interpretation of the signal in the brain, rather than nociception at the periphery. Interestingly, though, when human skin is exposed to extreme noxious cold (like, of example, dry ice or liquid nitrogen), the resulting pain is often descibed as a "burn" and, i can confirm, the immediate acute pain is "burn like". Thus, my hypothesis is that the human thermosensory system is more "tuned" to warn us of hot temperatures, since we are more likely to be exposed to noxious heat in a natural environment, than noxious cold. Consequently "hot" is more immediately painful than "cold", within the ranges we are normally exposed too. Its only when you get to extremely cold temperatures, that the cold interpretation becomes as acute as the hot response. Why then, as Seejyb reports, we have "about 30 "coldness" nerves for every "warmth" nerve", is a puzzle, however. But this expanded "thermo-space" for cold detection, could provide a mechanism through which a more moderate cold respose is mediated. Rockpocket 04:43, 19 September 2006 (UTC)

Thanks for the response(s). Makes alot of sense. Though, I suppose all of existence must be regarded as an "interpretation of (a) signal in the brain." Much respect to the Man, Descartes. - R_Lee_E (talk, contribs) 01:46, 20 September 2006 (UTC)

When you're talking about "burning" and "biting", you're not just talking about heat and cold perception. A stimulus that is sufficiently severe to be perceived this way is also provoking a pain response, which is conveyed by means of sensory neurons that are morphologically different from heat and cold afferent neurons, to different centers in the brain. In other words, extreme heat and cold evoke more than one type of sensation at once. Interestingly, temperature and pain perception follow the same neural pathway from the peripheral nervous system to the diencephalon-- the spinothalamic tract.--Mark Bornfeld DDS 17:39, 19 September 2006 (UTC)

Yes, that is a very good point. I was oversimplifying. Clearly there is cross-talk between the thermosensation and pain sensation signaling. Rockpocket 07:35, 20 September 2006 (UTC)

On a related note, if a substance is cold enough, exposure to it will create a sensation indistinguishable from burning. People who work with stuff like liquid nitrogen have to be careful. It's really weird.

Solvents

We are going to have to identify an unknown organic compound tomorrow in lab using IR Spectroscopy and it's observed melting point. When choosing a solvent to do recrystallization, we are to pick one from 1. Water, 2. Ethanol, and 3. Hexane. Is it safe to assume that water will dissolve polar compounds, hexane will dissolve non-polar compounds, and ethanol will dissolve both? --Russoc4 18:16, 18 September 2006 (UTC)

It is not 'safe' but I would call it a 'rule of thumb'. There are some organic compounds which will not dissolve in any of those.

watts into kwh

My alarm clock runs at 5 watts, or 5 joules per second. Would this mean that it consumes 1/200 kwh?—Preceding unsigned comment added by ChowderInopa (talk • contribs)

Yes, per hour. In one hour it consumes 5 watt-hours = 5/1000 or 1/200 kwh. Fan-1967 20:24, 18 September 2006 (UTC)

Usually people count kWh when they receive their monthly electric bill, so kWh/month may be a more useful unit. Your clock uses .005 kWh/hour * 24 hour/day * 30 day/month, or 3.6 kWh/month. If electricity costs you $0.10/kWh, that's a whole $0.36 you spend every month keeping your clock going. Foobaz·o< 02:13, 19 September 2006 (UTC)

First you divide the Joule by seconds. Then you multiply that by hours. And then you divide by months again. Or days. Or years. This is almost as bad as the imperial units system. Just stick to one unit for time, the SI unit 'second'. Then you'll only have joules and watts and it's clear what you are talking about (energy and power). DirkvdM 06:35, 19 September 2006 (UTC)

Unfortunately, no electric company actually bills in Joules, which is the real measurement. If I have the math correct, 1 kwh = 3600 seconds × 1000 joules/second = 3,600,000 Joules. Kind of a difficult conversion factor in calculating your bill. Fan-1967 14:10, 19 September 2006 (UTC)

butterflies

What do you call a group of butterflies?

Honestly I never seen them in more than 2s--Light current 21:46, 18 September 2006 (UTC)

a swarm of butterflies or a rabble of butterflies. search google under "collective noun"

They should only be called a swarm if it is a very bad horror film. Here are a myriad of other possibilities. MeltBanana 22:48, 18 September 2006 (UTC)

It's not on the list, but a "brothel of butterflies" really rolls off the tongue. Hyenaste ^(tell) 23:45, 18 September 2006 (UTC)

10/10. Excellent work. JackofOz 09:04, 19 September 2006 (UTC)

List of collective nouns for fish, invertebrates, and plants. Weregerbil 11:33, 19 September 2006 (UTC)

Why Do Men Have Nipples?

Simple question; likely a difficult answer. - R_Lee_E (talk, contribs) 21:46, 18 September 2006 (UTC)

Because God is good? --Trovatore 21:57, 18 September 2006 (UTC)

We has this one a few months ago.--Light current 21:59, 18 September 2006 (UTC)

Nipple#Male_Nipples... -- Consumed Crustacean (talk) 22:45, 18 September 2006 (UTC)

How would you feel and look if you didn't have any nipples? bibliomaniac15 00:14, 19 September 2006 (UTC)

Most people can feel and look without the using their nipples. As far as I know. MeltBanana 00:26, 19 September 2006 (UTC)

Yes, but it feels so much better when you do use them. Seriously. JackofOz 09:07, 19 September 2006 (UTC)

Ok, since the reference desk has wandered into chaos, and primally contains sarcastic and rude remarks for plain and simple questions (this question/answer-thread isn't that bad...Just look at the above entries) - I will try to answer your question. At least the easy answer: Both male and female nipples develops at a stage in the pregnancy when the babys gender is still undetermined. The genitals develop later. --Petteroes 11:57, 19 September 2006 (UTC)

Isn't it, more precisely, when the fetus is female, rather than undetermined? Steven Gould has an essay on this, I recall... Marskell 12:32, 19 September 2006 (UTC)

Freudian slips are very telling. "Primally" is spot on when it comes to nipples. My contribution, fwiw, was not meant flippantly, which is why I said "seriously". Whenever this question comes up, I remind folks of the sexual function of men's nipples. I know, I know, there's a difference between the biological purpose behind how they developed, and what they're good for now that we've got them. I'm more interested in the latter question. JackofOz 13:15, 19 September 2006 (UTC)

Stephen Jay Gould discussed this in an essay entitled Male Nipples and Clitoral Ripples in which he basically explains that the fetus has to have the roots of both genders' characteristics, so men have nipples because women have breasts, and women have clitorises because men have penises. Fan-1967 14:15, 19 September 2006 (UTC)

When you're an embryo, sex isn't determined until later on. I don't quite remember the week, but all people are essentially genderless until a certain point and sex specific organs will start to develope. Nipples differentiate from the tissue at a very early stage, so they are in both sexes. However, it isn't until later when sex organs develope and a the sex of the baby is determined do things like mamary glands develope that would make the nipples functional

Info on an american polar-expedition...

Hope you guys could help me out here. A long time ago I read an article in a science magazine about an american expedition with an exceptionally big tank, an armoured wagon that weighted too much for the enviroment it was going to explore, and eventually got itself stuck in the snow. I reckon it was during the early stages of The Cold War - around 1946 - 1956. I think the target for the expedition was to reach the central parts of Greenland, or the North Pole. The expedition was widely concidered a failure.

Does anyone know the name of the expedition?

fluid behind our cats ears

moved from Wikipedia talk:Questions

We have a four year old golden calico male.Our cat goldie keeps building up pockets of fluid behind his ears.He has had three hematobin operatoins.He also has asthma.He has been on full time antibiotics and prednisone.I hear that they are a very rare species because of their genetics.Can you please help us solve this problem.We love this cat very dearly and hate to lose him.We have heard rumors that golden calico males usually only live up to five years old.Please help SINCERELY JIM KERR. —The preceding unsigned comment was added by 24.105.219.35 (talk • contribs) .

First, let me clarify that a Golden Calico is a breed, not a species. Second, this "fluid behind the ears" doesn't sound like a life threatening issue from your description. Can you describe the quantity ? I would think the treatment would be to lance the skin and allow the fluid pockets to drain. StuRat 23:55, 18 September 2006 (UTC)

Calico is not a breed, it is a description of a coat pattern, and it only occurs in females. You see, the colors are on the X chromosome, and the calico patchiness comes from the alternating patches of x-chromosome silencing (i.e. barr bodies) in the young embryo. Thus Goldie could only be a "he" if he has klinefelter's syndrome, and Golden Calico can not be a breed unless this particular breed is parthenogenic...Tuckerekcut 01:36, 19 September 2006 (UTC)

Now that I have read your question more closely (sorry Jim), I have decided that your cat probably is a klinefelter male, which would corroborate your details. You can read about klinefelter's syndrome here on wikipedia, perhaps a description of the human phenotype will help you better understand the prognosis of your cat, there is also some info at Tortoiseshell cat. It may very well be that the problems you mentioned regularly go along with being XXY and a cat. I will also add that your cat's condition would probably be better described as a genetic disease than as a "rare species" or otherwise.Tuckerekcut 01:46, 19 September 2006 (UTC)

There's more than one way to have a male tortoiseshell (see Laura Gould's Cats Are Not Peas for the story of George, a rare fertile male calico who turned out to be an XXY/XY mosaic). On the more serious question, it sounds like the cat in question needs a vet more than Wikipedian's opinions. (By "hemotobin" do you mean "hematoma"? Your vet should be able to tell you why this is recurring), - Nunh-huh 06:49, 19 September 2006 (UTC)

I suppose thare are many possibilities, but straight klinefelter's is the most likely, at about 1/1000 live births. (How much more likely? I don't know how many chromosomes a cat has, but the likelyhood of being mosaic for two karyotypes like this is about 100 times the number of chromosomes in a typical cell, if this cat were a human, that would be about a 1 in 4600 chance, giving a total chance of having an mosaic x nondisjunction in a male of about 1 in 4.6x10^6.) If this cat were a human, I would recommend having him karyotyped, but that is not particularly cheap. As Nunh-huh said, a vetrinarian is your best bet, she will know if these symptoms are normal for your cat's disease.Tuckerekcut 11:57, 19 September 2006 (UTC)

38 chromosomes for cats. I can't see much benefit in karyotyping, other than assuaging an intellectual curiousity. Better to spend the bucks getting veterinary care.- Nunh-huh 16:49, 19 September 2006 (UTC)

About the same benefits as with a Down's patient. With a full karyotype you know exactly what's going on (i.e XXY vs X/XY mosaic in the cat, as with 47 X(x/y) +21 or 46 X(x/y) der(N;21) or some mosaic with one of those in the Down's patient). Sometimes it helps the family to get a solid, definite cause. But sometimes even that results in little benefit.Tuckerekcut 02:40, 20 September 2006 (UTC)