Wikipedia:Reference desk/Archives/Science/2007 November 25

= November 25 =

Can chiropractors prescribe scheduled medicines?
Like pain killers? Biochemza, 00:07, 25 November 2007 (UTC)
 * Not in the UK, unless they are also one of the following :-

"NHS prescriptions are most commonly written by your GP for you to take to your community pharmacist (chemist) to collect.

From 1 May 2006, qualified Nurse Independent Prescribers (formerly known as Extended Formulary Nurse Prescribers) are able to prescribe any licensed medicine for any medical condition within their competence, including some controlled drugs.

''Doctors working in NHS hospitals also write NHS prescriptions. In most cases, you will be asked to take your prescription to the hospital pharmacy to pick up your medicine. Sometimes you will be asked to take your prescription to your local chemist - usually when the hospital pharmacy cannot supply your medicine.''

An NHS dentist can also provide you with an NHS prescription if you need treatment for a dental or oral condition.

''Supplementary Prescribers are pharmacists, chiropodists, podiatrists, physiotherapists and radiographers who have undergone specialist training. They may prescribe any NHS medicine provided it is in partnership with an independent prescriber who gives the initial diagnosis and starts the treatment. The Supplementary Prescriber then monitors the patient and prescribes further supplies of medication when necessary."'' - Source is http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=1629 Exxolon (talk) 00:24, 25 November 2007 (UTC)

In the U.S., all States currently exclude prescribing drugs from chiropractic practice. There have been lawsuits from chiropractors seeking to change this; none have been successful. - Nunh-huh 03:31, 25 November 2007 (UTC)
 * That's probably because many chiropractors are homeopaths. -- JSBillings  17:23, 25 November 2007 (UTC)
 * Actually, it's probably the other way around. Because they're not allowed to prescribe real, scientifically tested, working medicines, they resort to prescribing the unregulated, pseudoscientific placebos called "homeopathic remedies", which are usually just sugar/lactose pills or water/alcohol, thus are generally harmless and don't count as drugs. --  Hi  Ev  13:35, 26 November 2007 (UTC)

Illegal Plant - USA
What plants are illegal to own/possess in the US? --WonderFran (talk) 00:22, 25 November 2007 (UTC)


 * A number are on the Controlled Substances Act schedule list, which depending on their "schedule" gives them various degrees of legality. Marijuana, psilocybin mushrooms, and peyote are always illegal (under US federal law). Without a prescription, opium poppies and coca leaves are illegal. Those are the ones that jump out immediately to me. --24.147.86.187 (talk) 00:43, 25 November 2007 (UTC)


 * Note that in some local jurisdictions there are plants that are illegal because of the threat they pose to the ecosystem and/or invasive. See, for example, the Illinois Exotic Weed Act, which bans a number of plants from the state of Illinois. To compile all of those would be a very long list and require a lot of digging into state and probably local laws. --24.147.86.187 (talk) 00:51, 25 November 2007 (UTC)


 * (Edit conflict) Certain plants are also considered noxious weeds and are illegal to possess on the basis that various governments (local, state, or federal) are trying to stamp out those plants. We used to use a particular weed in our fish pond as an oxygenator, but the fish loved to eat it as well; we can't get that weed any more as it is now illegal in New Hampshire.


 * Atlant (talk) 00:52, 25 November 2007 (UTC)


 * Nuclear plants, unless you have the proper permits, which can be quite a headache to acquire. --Sean 01:17, 25 November 2007 (UTC)

Does my sun conure have another name?
My sun conure is named Sally. She responds and comes over to me when I call her by name. It's pretty clear that she knows that this is the 'human speak' call I use to refer to her in particular as an individual. Do sun conures also have names in their own 'parrot speak'? It would seem obvious that she does not sit and think of herself as "Sally the Sun Conure" - how would a bird which can speak only a few words of English be expected to know what name humans have given to her entire species? —Preceding unsigned comment added by 84.66.52.166 (talk) 00:25, 25 November 2007 (UTC)


 * My brother used to do research trying to decipher parrot-speak. He said that in groups of parrots (in some species) a single member could alter its song to more closely match that of another individual parrot, and in this manner would attract the attention of that parrot.  Not a "name" per se, but certainly some species have ways of calling to a specific individual.  Someguy1221 (talk) 02:42, 25 November 2007 (UTC)


 * Avian_intelligence. This article is beautiful. SamuelRiv (talk) 03:18, 25 November 2007 (UTC)


 * Hmmm. I wonder if that goes some way to explain why many species of parrot mimic human sounds in the first place? I know from my experience with budgerigars that they (the males in particular) will often weave the various human words and phrases that they've learned together into a 'song'. --Kurt Shaped Box (talk) 12:57, 25 November 2007 (UTC)


 * I don't think names are things that animals naturally deal with. It seems that dogs, cats and parrots (at least) can be trained to recognise some specific sound as being 'theirs' but whether they even think of it as a 'name' is hard to say.  Whether your Sun Conure is recognising "Sally" as her name - or whether it is the intonation of your voice for the entire senntence "Sally come here" that works is anyone's guess.  Our Cocker Spaniel dog would get very excited when we said the word "Walkies!" because he loved going for walks.  He would actually run off and find his leash and bring it to us when we said "Walkies!".  My wife contended that he understood the word - but I convinced her not because I could say "Tomato Sandwiches!" in the exact same tone of voice and cause the dog to rush off and fetch the walkies apparatus.

Furthermore, if I used the word "Walkies" in a completely neutral tone of voice in the middle of another sentence, the dog didn't recognise it at all. I eventually discovered that if I mimed saying "Walkies!" without making a single sound, the dog would respond. Dogs (and probably parrots too) are sensitive to a wider range of human expression (including body language, voice intonation, maybe even pheremones) than we are conscious of delivering to them. It's easy to assume they detect one kind of communication (words for example) when in fact it's something completely different.


 * Inserting a response to this point: what that this means is that the dog isn't correctly discriminating which aspects of your pronunciation are phonemic and which aren't. It's like the way some speakers of other languages can't tell the difference between the English words "ship" and "sheep", or "fat" and "vat"; and speakers of English have to learn that in Chinese the same word pronounced in a different tone becomes an unrelated word, or that in Hindi the aspirated K in English "kin" is a different consonant than the unaspirated K in English "skin".  This sort of thing doesn't prove that the dog doesn't have the concepts you're using when you talk to it, only that it has trouble with human-accented pronunciation.  (Of course this also doesn't mean that it does have those concepts; I'm only talking about what is evidence for what.) --Anonymous, 22:08 UTC, November 25, 2007.


 * But the difference wasn't as small as "fat" and "vat" or "ship" and "sheep". It was "Walkies" and "Tomato Sandwiches" (or any other phrase of many, many syllables.  But even miming saying the word without making any sound produced the same response.  Dogs are AMAZING at interpreting 'body language' signals that we aren't even aware we're giving off.  I'm convinced that the sound helps (eg if the dog can't see you) - but that's not the only component of the dog's perception that's involved. SteveBaker (talk) 21:19, 26 November 2007 (UTC)


 * I think you're missing my point. I'm saying that what you see as a big difference (between "Walkies" and "Tomato sandwiches") may be a small difference in the dog's perceptual system, just as the difference between "fat" and "vat" is small in yours.  And when you say that language consists of sounds and does not include body language, that's like an English-speaker saying that tone is not phonemic, even though Chinese it is; in dog "language", your body language seems like just another part of your utterance and is to be taken into accuont.  --Anonymous, 00:09 UTC, November 28.


 * The only case I'm aware of where animals have invented names themselves is in whale song - where I believe researchers have noted specific phrases in their song that are used by many members of a pod but only when one specific individual is present or being searched for. That suggests that whales have names...although there are perhaps other interpretations.


 * I bet that if you start calling your bird by a different name every day - but call her with the same tone of voice and body language - then you'll get exactly the same result you get when you call her "Sally".  It's an easy experiment to try.  Start off with names that are similar ("Betty" - has a similar number of syllables) and then try wilder combinations.


 * SteveBaker (talk) 10:01, 25 November 2007 (UTC)


 * Another thing to consider is whether your bird takes your calling of her name to be a signal that you (the large beastie that provides her with her only regular form of social contact) are ready to 'interact' with her, feed her some tasty fruit (or nuts, or whatever snacks you give her) and perhaps preen her itchy head feathers. --Kurt Shaped Box (talk) 12:57, 25 November 2007 (UTC)


 * Yep - exactly. The parrot translation of the word "Sally" could easily be "Hi! It's me!" or something like that.  Have you ever seen the British TV comedy "Coupling"?  There is a great episode ("The Girl with Two Breasts") in which one of the characters, Jeff, is chatting with a woman in a bar who doesn't speak English.  The first half of the show has Jeff speaking English and her speaking Hebrew (I think).  They both think they are managing to understand what's going on and they are getting on just fine but - in the second half of the show they replay the exact same scene but with him speaking Italian and her speaking English so you can hear the conversation from her point of view.

The degree of misunderstanding is of course SPECTACULAR - and somehow he mistakenly assumes that the Hebrew word for "breast" is the girls' name...um...I guess you need to have seen the show! But if that level of miscommunication is even plausible between two humans (and it does seem pretty plausible) - then on an interspecies basis, anything is possible! SteveBaker (talk) 16:31, 25 November 2007 (UTC)

Identify this plant
I bought a plant, but it had no tag saying what the species was, so I was hoping for an answer. I took a photograph of the plant, and uploaded it.

It was purchased at a home depot store in the Twin Cities, Minnesota for 15USD, and only came with one tag, which says "Tropical in Winter G/S". —Zachary talk 03:58, 25 November 2007 (UTC)


 * It looks likely to be Dracaena Marginata. Take a look at Google images:  here and the Wikipedia article here   -- dharma  —Preceding unsigned comment added by 24.86.250.218 (talk) 04:21, 25 November 2007 (UTC)


 * Yes, it sure is of Dracaena genus (which is a common houseplant), but it could either be Dracaena Marginata as was pointed earlier or it could also be Dracaena Cincta. These two species are known for their distinct pinkish edge in the leaves which is evident from the picture you have provided. Hope it helped. DSachan (talk) 04:39, 25 November 2007 (UTC)


 * Good point - the Wikipedia article mentions that D. marginata is often confused with D. cincta or D. concinna. -- dharma  —Preceding unsigned comment added by 24.86.250.218 (talk) 05:33, 25 November 2007 (UTC)

Another identification, please
My mom found this weird looking caterpillar at home, so I took a snap, when I blew some air on to it, it curled up a bit and showed me these faux eyes that it has got, and I admit, it scared me a bit. Is this going to be a moth or a butterfly when it undergoes metamorphosis ? Thanks for the help in advance :) SiegerKranzMeer 08:13, 25 November 2007 (UTC)


 * It looks a lot like some sort of hawk-moth caterpillar, especially with the faux eyes that you mention. Richard Avery (talk) 08:55, 25 November 2007 (UTC)


 * Oh dear, this is very difficult one. First of all, are you sure that this is a caterpillar? It could be some weird worm also. But it sure looks like a caterpillar seeing its segmented body and structure. The problem is there are about 180000 species in this lepidoptera order (which is huge) and all of them form caterpillar. So, it is obviously a tough task to pick out one of them. Furthermore, some organisms of order hymenoptera also produce larvae which look very similar to caterpillars produced by lepidopterans and hymenoptera is another big order. But here also, I can be sure that it is of lepidoptera order only because these caterpillar tend to have shorter abdominal length in contrast to the hymenoptera larvae which have longer abdominal length to generally accomodate more prolegs. So their body tends to have more segments. In this picture I can see only about 8 segments, which is quite common in lepidopteran caterpillars. This creature showed you its eyes because it always does so to frighten away or trick its predators but in your case, its predator happened to be a human, so this trick didn't work. :) Now if you have a garden around your home, the possibility could be that it may be a caterpillar of geometer moth, but that also you can tell by the way it was moving. If you noticed how many prolegs it had, things would be a bit easier. If it had only one pair of abdominal proleg, it could be the caterpillar of Geometer moth, which makes a very large family and are fairly abundant in gardens. If it had 5 pairs of prolegs, it could be caterpillar of hawk moth also. Butterfly caterpillars generally tend to be shorter, hairy and more vividly colored. But having said that, I must admit that this could be anything ranging from being a worm, some skipper's larva, some weird moth's caterpillar or even a caterpillar of a beautiful butterfly. I pointed out the difficuly in the beginning. Biological world can always be bizarre and astonishing. It always has surprises for you in its store. So, don't take my suggestions as final. DSachan (talk) 09:26, 25 November 2007 (UTC)

Thank you Richard and, DSachan: for taking the time out to write such a long but detailed explanation. :) 123.176.43.125 (talk) 11:42, 25 November 2007 (UTC)


 * I'm hopeless at these 'please identify this insect' questions, but there is one part of your question I can help on. Will it become a moth or a butterfly?  Our article on Moth says "The division of Lepidopterans into moths and butterflies is a popular taxonomy, not a scientific one" - in other words these words "moth" and "butterfly" are not meaningful in a scientific sense.  Basically, we humans have decided that "pretty" lepidoptera are butterflies and "ugly" ones are moths - but since this is in the eye of the beholder - it doesn't really fit the underlying science so until someone can nail it down exactly what species this is, we have no way to guess based on some general characteristic of "moth" catapillars that might differ from "butterfly" catapillars.


 * Also, in general, please - when you ask us to ID plants or animals tell us where in the world you found it! Knowing which region of which country it comes from narrows down the search to much smaller number and perhaps directs us to online resources specific to that area.  Having some idea of the local habitat (woodland, grassy plains, farmland, urban, etc) also provides a little more information.


 * SteveBaker (talk) 16:13, 25 November 2007 (UTC)

Will keep that in mind (about the 'giving the location' part) This one was taken at hyderabad, India. And I did not know that the distinction between moths and butterflies was a man-made one. Thank you for clearing that up. SiegerKranzMeer 21:33, 25 November 2007 (UTC)
 * What's That Bug? and BugGuide can also help, if you're not in a hurry. :) --Kjoonlee 20:48, 26 November 2007 (UTC)


 * Actually, there is a significant difference between moths and butterflies beyond superficial taxonomy, which is why there is an article for differences between butterflies and moths. It's a common myth that the differences are just taxonomic, at least among taxonomists ironically. It would help to know if you found it eating anything; that narrows down things. I would agree with Richard that it's some sort of hawk-moth because of what looks like a horn on its posterior with a false-head and false-eyes. --76.214.203.95 (talk) 06:07, 30 November 2007 (UTC)

Ammonium chloride
In the article entitled Ammonium chloride shouldn't the following sentence, "Ammonium salts are irritantt to the gastric mucosa and may reduce nausea and vomiting." read "Ammonium salts are an irritant to the gastric mucosa and may induce nausea and vomiting." ${\aleph_0}^{\aleph_0}$ (talk) (email) 08:33, 25 November 2007 (UTC)
 * Yes it should, according to this classic text. Rockpock  e  t  09:00, 25 November 2007 (UTC)
 * Thanks. Corrected. ${\aleph_0}^{\aleph_0}$ (talk) (email) 09:21, 25 November 2007 (UTC)

Lysogeny
At lysogeny, the article includes mention of herpes, on the basis of its genomic integration, yet HIV is not considered lysogenic. Either herpes is not lysogenic because the term 'lysogenic' refers to bacteria-infecting viruses or else HIV is lysogenic... right? --Seans Potato Business 15:48, 25 November 2007 (UTC)
 * I'm not sure but I think the term lysogeny could mean two things: One is like you said, genomic integration of phage DNA to bacterial DNA (a definition I suspect doesn't apply to HSV or HIV because the viruses attack human cells, not bacteria).  Two, it refers to the latent state of the virus, where the virus stays dormant inside the host's cell for some time. (Which would apply to both HSV and HIV) 128.163.224.198 (talk) 19:31, 25 November 2007 (UTC)
 * In the context of viruses that infect bacteria, see this textbook. I would not use the term "lysogeny" with viruses that infect eukaryotic cells....I'd use the term "latent infection". --JWSchmidt (talk) 03:37, 26 November 2007 (UTC)
 * I've removed the herpes section from the lysogeny article. --Seans Potato Business 07:36, 26 November 2007 (UTC)

Respiratory Acidosis
In chronic respiratory acidosis, what is the purpose of HCO3- (bicarbonate), if it can't actually buffer the H+ (the elevated pCO2, resulting in the cause of the acidosis, would prevent buffering?). The system wouldn't be able to compensate for a failure of itself would it? (hope it makes sense)


 * I'm not sure at all, but my initial guess would be that it comes from the reaction CO2 + H2O -> H2CO3, carbonic acid, which HCO3- salts would buffer. Respiratory_acidosis seems to confirm this to some extent. SamuelRiv (talk) 19:43, 25 November 2007 (UTC)


 * Bicarbonate is only a partial buffer. The carbonic anhydrase reaction (H2O + CO2 <=> H2CO3 <=> H+ + HCO3-) explains where your acid comes from - more CO2 drives H+ + HCO3- production.  The rest of the compensation comes from other buffers including phosphate, and renal excretion of H+. Mattopaedia (talk) 05:08, 28 November 2007 (UTC)

Rodents
What is the differences between a Gerbil, Hamster and a Guinea Pig?

XX##XX —Preceding unsigned comment added by 196.208.75.208 (talk) 17:09, 25 November 2007 (UTC)
 * I've wikified the different animals in your question. The quick answer is their original native habitat, both the gerbil and hamster are from europe and asia, and the guinea pig is from south america. --  JSBillings  17:20, 25 November 2007 (UTC)


 * Guinea pigs are huge - 8" long - about the size of a large, domesticated rabbit. Hamsters and Gerbils are both just a couple of inches long - the same size as a mouse.  Gerbils are distinctive because of their large hind legs and feet.  All three are rodents and they all eat similar things and make good pets.  Hamsters are loners - they don't very much like the company of other hamsters - which means you can have just one of them without causing them stress - they live in tunnels and are naturally nocturnal, They adapt well to those crasy cages with the maze of twisty tubes (which are quite amusing but a pain to clean out a couple of times a week). They can be grumpy (and may bite) if you try to interact with them during the day.  Guinea pigs (being large) need lots of space to roam around in - so you're going to need a large (possibly outdoor) enclosure for them.  You can keep guinea pigs and rabbits together - they get along quite well and eat similar foods. SteveBaker (talk) 18:19, 25 November 2007 (UTC)


 * I recommend looking at the articles on them in Wikipedia, perhaps by following the links JSBillings gave you. Steve's guide is pretty good, but there are different species of hamster (Syrian hamster, Russian dwarf hamster, Chinese hamster, etc). A russian dwarf is about the same size or smaller than a mouse, but a syrian hamster is rather bigger (unless you've got huge mice!), and dwarf hamsters are frequently kept with each other. A grown gerbil is also rather bigger than a mouse, but these things vary. Anyway, read the articles and look at the pictures. Skittle (talk) 22:59, 25 November 2007 (UTC)


 * Another key difference between hamsters and gerbils is that hamsters only have very short tails (as do guinea pigs and rabbits) while gerbils have long rat-like tails.GaryReggae (talk) 13:14, 26 November 2007 (UTC)


 * Gerbils have long furry tails, not like rats :) Anyway, I still feel viewing the articles would be the best course of action, since there are a lot of differences and it's hard to prioritise what is wanted. Skittle (talk) 16:47, 26 November 2007 (UTC)


 * Also a crucial point: gerbils are about the only rodents that don't smell up the place, because they are desert dwellers and don't drink much so they don't urinate much. Otherwise, i find hamsters nicer, and guinea pigs even nicer than that. Gzuckier (talk) 21:42, 26 November 2007 (UTC)

Tornado's
Why is it that there is no tornado's in South Africa?

Antoinette —Preceding unsigned comment added by 196.208.75.208 (talk) 17:14, 25 November 2007 (UTC)
 * Actually, South Africa is one of the most likely places for a tornado to occur. Sancho 18:12, 25 November 2007 (UTC)
 * Dust devils are a common sight on the Karoo. Rockpock  e  t  20:06, 25 November 2007 (UTC)

Stars on moon
Can you see stars when your on the surface of the moon? I seem to remember from somewhere that you cannot, but why would that be? Is the Earth so bright that it outbrightens (new word) all of them, just as the Sun does here? Imaninjapiratetalk to me 18:25, 25 November 2007 (UTC)


 * It depends on the direction you look and if you're in lunar day - see this. See also examination of Apollo moon photos. -- Finlay McWalter | Talk 18:33, 25 November 2007 (UTC)


 * I don't like the first answer in the first source you attached. In lunar day, the sun is indeed very bright and the moon surface reflects a significant amount of that light. However, the light is not diffused into the atmosphere, so conceivably you should be able to look straight up while shielding the light from the surface, the Earth, and the sun, and see plenty of stars, even in the daytime. SamuelRiv (talk) 19:47, 25 November 2007 (UTC)


 * Yes - you can see LOTS of stars from the moon - more so than here on earth because (a) there is no atmosphere to get in the way and (b) at night there is no light pollution. From the side of the moon nearest the earth, the earth is a very bright object that might make nearby stars a little hard to see - but on the other side of the moon it should be no problem at all. During the two-week-long night, on the far side of the moon from the earth, the view of the stars would be absolutely unparalleled.  The reason you think there might not be stars is probably because of the annoying conspiracy theorists who claimed that the lack of stars in photographs taken during the Apollo landings was proof that the missions had never taken place and that the photos were faked.  In truth, the reason there were no obvious stars in the photos (actually, you can see some) was because the brighter objects in the foreground (the astronauts, lander and lunar surface) were being lit by EXTREMELY bright sunlight (brighter than on earth because of no atmosphere) - and the camera's lens had to be stopped down to prevent it from over-exposing the film and washing out the whole image to a white blur.  When you do that, dimmer objects like stars get dimmed down to almost nothing. SteveBaker (talk) 19:50, 25 November 2007 (UTC)


 * It's possible to see stars on the Moon even when the Sun and the Earth are above the horizon. The sky will be pitch black because there is no diffraction of light, so as long as empty sky fills your field of view and you cannot see the Sun, Moon, or surface objects, night vision will set in and stars will become visible.

An astronaut enjoying the heavens in daytime must of course avoid looking at the lunar surface without going indoors and allowing his eyes to adjust to highler light levels. --Bowlhover (talk) 21:33, 25 November 2007 (UTC)


 * Stars are rather dim objects, and eyes adjust depending on levels of brightness. So, if there is something bright enough in your visual field, your eyes will adjust so you can see the bright object properly, but that will also make the stars effectively invisible to you.  However, if you block out other light, then the stars should become visible again (though your eyes may take a little while to readjust.)  Cameras work the same way.  Whether you can see the stars from the Moon depends on whether or not there is any other light in your visual field that would hide them (and also the transparency of your helmet, I suppose.) --  Hi  Ev  14:03, 26 November 2007 (UTC)


 * However, something as simple as an old toilet roll tube would serve to block out the light and enable you to see stars in daylight. To get the best view, you'd want to be dark-adapted - which either means waiting a week or two until nighttime - or spending 20 to 30 minutes with the blast shield of your helmet down first. (You DO have a blast shield - right?! All the trendy space-suits have them these days! :-)  —Preceding unsigned comment added by SteveBaker (talk • contribs) 21:14, 26 November 2007 (UTC)
 * Somehow I don't think holding a toilet paper roll tube up to your space helmet's face shield would work too well. :-P --  Hi  Ev  22:30, 26 November 2007 (UTC)
 * Oh - so the excuse that I'd used up all of the toilet paper wiping sticky fingerprints off of the visor isn't going to cut it either? Darn! SteveBaker (talk) 23:23, 26 November 2007 (UTC)