Wikipedia:Reference desk archive/Science/2006 October 2

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[edit] Taxonomy for Extraterrestrial Life

There's something I've been wondering about for years: If/when we do find extraterrestrial life, how would we go about classifying it? Considering the ideal of having taxonomy reflect genetic lineage, would you start an entirely new tree for them - maybe put all life on Earth in "Superdomain Terrania", and put all life on Mars in "Superdomain Martiana"? Does anyone know of any proposals that have been made for extraterrestrial taxa?

Taking the question a bit further, if we were to make a new superdomain for another planet, then would taxonomy tolerate "duplications" of basic taxa used for life on Earth? I mean, could you have "another" Domain Eukaryota for another planet, if a group of extraterrestrial organisms fit our commonly accepted standards of what a eukaryote is? Could you have "another" Kingdom Animalia for another planet, if a group of organisms unambiguously met our commonly accepted standards of what an animal is?

Many thanks to whomever responds, --The Lazar 00:43, 2 October 2006 (UTC)

See Xenobiology, for starters. — X [Mac Davis] (SUPERDESK|Help me improve)01:15, 2 October 2006 (UTC)
Well, I've looked there, but it doesn't really seem to touch on this specific issue of "xenotaxonomy". Google searches haven't yielded much either. I asked over at Talk:Extraterrestrial life, but they recommended that I ask here. --The Lazar 02:39, 2 October 2006 (UTC)
A very interesting question. Since our classification scheme tends to represent evolutionary relationships (cladistics), I would assume as you say that a new tree would have to be developed. Of course we don't know what extraterrestrial life might be like, organic, cellular, and so on. I tend to think that using duplicate names would be a bad idea in general. Especially with today's taxonomic thinking, the "commonly accepted standards" are more of a surrogate for genetic lineage; that is, the true definition of some division is something like "all descendants of the most recent common ancestor of x and y", and if they all just happen to be give birth to live young or something due to their shared ancestry, that just makes it easier to classify. Of course, xenobiology might reveal either that life can come in enormous variety or perhaps there aren't that many ways for life to be successful; so if we were to find extraterrestrial life it may end up that we find similar characteristics as on our own world. — Knowledge Seeker দ 02:42, 2 October 2006 (UTC)
I had thought about xenotaxonomy for a while too and I came up to pretty much the same idea that you have, Lazar. A new planet and new genetic lineages would mean you could start over with the names. There might be some confusion but when clarifying one could simply insert the superdomain somewhere like "Apis florea Martiana" and "Apis florea Terrania".
I really hope there aren't already bees on Mars. Ƶ§œš¹ [aɪm ˈfɻɛ̃ⁿdˡi] 03:24, 2 October 2006 (UTC)
I doubt that the nomenclatural bodies would allow the reuse of names, assuming that Linnean taxonomy still stands. If something like PhyloCode is etablished, then that problem doesn't exist.
As for the original question, it should form a new clade, distinct from all other known life. Guettarda 03:54, 2 October 2006 (UTC)

Its possible however that we find extraterrestial life that is related to life on Earth, in which case those species could be integrated into the existing classification schemes. AmitDeshwar 06:07, 3 October 2006 (UTC)

If it's intelligent life, we can just as them. B00P 08:46, 3 October 2006 (UTC)

[edit] Codon inversion

Hi

I'm doing a third year bioinformatics course at varsity, and I'm researching for a presentation. My topic is codon inversions/reversal in DNA. Eg ABC DEF GHI -> GHI DEF ABC. I've come across them from time to time when sequence gazing. Does anyone know of any work done on these? Any cases in the literature? I've had quite a hard look, but I'm finding search terms hard to pin point, and information even harder. The only paper I've found is Santos et al 2004 J. Biol. Chem. pp17596-17606. Thanks for your help!

Aaadddaaammm 03:05, 2 October 2006 (UTC)

third year bioinformatics? you must know already the NCBI is your friend B-). go to pubmed, and get searching. a keyword to get you started is pericentric inversion, a rather special case of gene inversion. good luck! Xcomradex 07:33, 2 October 2006 (UTC)

[edit] air pressure cuts

I read somewhere that there is a phenomena where air pressure can cut people or things, it has something to do with a vacuum or something. apparently in japan they call it "kamaitachi" is this a real phenomena or just a legend? if it is real how does it work?

curious 17:00 01 october 2006

A high pressure air source certainly could cut like a torch, particularly on soft material like human flesh. Of course, the air velocity would quickly dissipate, so the person would need to be very close to the source to be cut by it. StuRat 16:45, 2 October 2006 (UTC)

High-pressure water can cut you, since it can cut through metal. Here's a funny article on whether high-pressure steam can cut a person in half (probably a magician has done it on doctored video!) [1] But nothing on air. --Zeizmic 17:18, 2 October 2006 (UTC)

Note: we do have an article on kamaitachi, though it refers to a mythological phenomenon.  freshofftheufoΓΛĿЌ  03:30, 3 October 2006 (UTC)
High pressure steam will cut to the bone as well as scald. High pressure hydraulic fluid from a small pinhole leak can penetrate the flesh and accumulate in the tissues, requiring surgery.Edison 04:41, 3 October 2006 (UTC)

Guns with blanks in them can kill, if they are placed directly against the head. StuRat 20:31, 4 October 2006 (UTC)

[edit] Glucosamine and Diabetes

Dear Sir/Madam: I am looking specifically for any information or sources you can offer to reference regarding the effects of orally taking Glucosamine for someone with Diabetes. This person is not insulin dependent, the diabetes is primarily controlled by a combination or diet and pills(not sure what kind). Any help you can offer would be greatly appreciated.

Thank You, 69.130.36.6 16:02, 2 October 2006 (UTC)

As far as I know, the two are completely unrelated, glucosamine is for joint health, and diabetes is a pancreas/blood sugar issue. 16:42, 2 October 2006 (UTC)

Since millions of older adults have both conditions the question is a good one. The theoretical concern is some animal evidence based on large doses (larger per weight than humans would take) showed moderate reduction of insulin sensitivity. This might be a concern in someone with partial or early type 2 diabetes, because it could hasten progression of the diabetes. On the other hand there have been remarkably few reports of this in people. Here is a concise and reassuring summary of the problem. At least with diabetes (as opposed to, for example, cancer) you have in your hands the tool to see if a treatment is helping or worsening the diabetes. For an excellent brief overview of glucosamine and chondroitin for arthritis, see Stephen Barrett's synopsis of the evidence. Diet supplement company sites should be considered advertising, not balanced information. Good luck. alteripse 17:38, 2 October 2006 (UTC)

[edit] Bird Eggs

Why do birds lay unfertilized eggs? For such small animals, wouldn't it be a tremendous disadvantage to be losing so many nutrients every day? (In the case of chickens.) --Demonesque 16:21, 2 October 2006 (UTC)

It's similar to menstruation in certain mammals. Unfortunately, no elegant method has ever developed to allow the animal to know whether an egg is fertilized, so it can make a decision about what to do. Most animals just make full preparations as if the egg were fertilized. One exception seems to be cats, where the male penis has a barb that injures the female, and this somehow triggers the preparation for kittens. Not a very elegant method, but better than none, I suppose. StuRat 16:32, 2 October 2006 (UTC)
Actually it doesn't trigger preparation for kittens at all. Cats are induced ovulators which means if they aren't mated with by a male with barbs (neutered males lose the barbs) that they don't ovulate at all and no eggs are released. Great mechanism to ensure conception, but somewhat unrealted to chickens. pschemp | talk 19:07, 2 October 2006 (UTC)
And you don't consider cat ovulation to be "preparation for kittens" ? There would be very few kittens without ovulating cats. StuRat 20:37, 2 October 2006 (UTC)

I suppose there could be an evolutionary advantage to unfertilized eggs, if they provide decoys for predators who might otherwise get the fertilized eggs. StuRat 16:37, 2 October 2006 (UTC)

In rare cases the unfertilized birds eggs develop into embryos. See also parthogenesis for comparison; it exists among many non-avian species.---Sluzzelin 16:42, 2 October 2006 (UTC)

Don't forget that chickens have been selectively bred for the egg laying trait, so its not the same as if their genes were not subjected to artificial selection. pschemp | talk 19:07, 2 October 2006 (UTC)

Wow, thanks. --Demonesque 17:42, 2 October 2006 (UTC)

Birds are morelikely to lay infertile eggs when they are in unnatural circumstances. I used to have a single lovebird which laid eggs regularly. In the wild, she would have been around other lovebirds and had a mate to fertilize those eggs. --Ginkgo100 talk · e@ 21:43, 2 October 2006 (UTC)

I have a personal experience whereing the egg i broke to make ommelette had blood inside it. I couldnt eat it. What would have you (i mean other editors here) done in such a case.nids(♂) 09:31, 3 October 2006 (UTC)
Yes, wearing a bloody egg would be disgusting, as would eating one. I'd toss it out, too. StuRat 16:54, 3 October 2006 (UTC)

[edit] Strobe

Is there a way I could produce strobe flashes, using only batteries as the power source? All bright strobes seem to use mains power, but if I need only a few flashes, would batteries do? I need a strobe for a school science fair, where we are not allowed to use mains power. We want to try and stop the motion of various things. Many thanks! --86.142.195.245 18:10, 2 October 2006 (UTC)

Since you used the term "mains power" I'll guess that you are in the UK. However, a simple Google search returns a lot of hits. You'll just have to narrow it down to local suppliers. --LarryMac 18:19, 2 October 2006 (UTC)
Some fairly suitable capacitor banks would do fine surely. Philc TECI 19:08, 2 October 2006 (UTC)

Sure, just shine a flashlight ("electric torch") through a battery-powered fan (they sell those for stadiums, etc.). (I'm afraid I don't know what you call an electric fan in the UK, perhaps a "flugglethump" ?) :-) StuRat 20:05, 2 October 2006 (UTC)

You can use a battery to charge up a capacitor, and then press a switch to discharge it through a lightbulb, or an LED (make sure you don't put too much current through it though). The hard part might be getting a suitably short pulse of light. A quick finger on the switch might be able to do it (or even just the capacitor's discharge time, if resistance isn't too strong), but you can also build a circuit that produces a certain pulse length with a 555 timer IC (rated for a suitable voltage). - Rainwarrior 20:24, 2 October 2006 (UTC)

It wasnt my first thought, but StuRats idea is probably the simplest a nd safest way to do this. Instead of a fan though, you could make your own strobe wheel- just a carboard wheel with some narrowish slots cut around the periphery. A small dc electric motor to drive it and a bright flash lamp would probably do the trick all without mains power 8-)


Many thanks for your time and effort people, I think I like the idea of the fan, that'll be the simplest to implement. Last year we got a bit over-ambitious, and I'd like to keep it simple, so we'll try the strobe wheel. Thanks! This reference desk is very useful!--86.142.195.245 21:01, 2 October 2006 (UTC)

Battery + Inverter + mains-powered-stroboscope. Or if you're electrically creative and competent to work with ~300 volts, I think you'll find that you could take the circuitry from a battery-powered camera strobe (as found in disposable cameras), exchange the bulk storage capacitor for a much lower value (so it recharges much faster), rig up a repetitive triggering circuit, and Bob's your uncle.
Atlant 23:43, 2 October 2006 (UTC)
Yes thats how we'ed do it, but I didnt want to encourage schoolkids to mess around with dangerous voltage! 8-(--Light current 00:52, 3 October 2006 (UTC)
Speak for yourself, Light current ;-) ! By sixth grade, I'd built a Van de Graff generator and a Tesla coil and was routinely in jeopardy of sudden death by electrocution! It's a wonder I ever lived to edit here! Then again, a few more schoolkids playing around with ~300 VDC and we might have a bit less vandalism around here from the study-hall set ;-)!
More seriously, because the battery-operated strobes are (generally speaking) isolated from earth/ground and physically fairly compact, there's pretty low odds of someone generating a life-threatening shock from them, although reasonable care must of course be taken. They might not be a bad introduction to high-voltage electronics.
Atlant 15:55, 9 October 2006 (UTC)

[edit] I'm searching for information on the workability and physical characteristics of pure Tungsten metal

Monday, 10-2-06 Portland, OR 12:57pm West Coast, Pacific Time

Who on the Reference desk/Science page would be an authority/expert on pure Tungsten metal? I'm searching for a cost effective retail source of this metal; considering my extremely low income level, what is the best, lowest price of retail pure Tungsten? There are plenty of websites that sell either scrap or new tungsten, but unfortunately the purity of either of these forms can vary from website to website. The purist form that I found on one particular website is 99.95% in foil form at $146.0 for a specified size(in metric units). Does anyone in the Reference desk/Science page heve any physical work experience with pure Tungsten metal? Is the metal compatible with common workshop tools such as powertools, tinsnips, handsaws, etc.? With these common workshop tools, I wish to fabricate my own storage/holding container for "Dry Ice": This is for a private, experimental science project that I'm cogitating; Is Tungsten tough and strong enough to tolerate physical contact with "Dry Ice" for an indefinite duration of time, or does pure Tungsten undergo any adverse chemical reaction with "Dry Ice"?

From: MyPresentCPUisTooSlow, new registered user since 9/06

Google should give you all the suppliers. [2]--Light current 20:59, 2 October 2006 (UTC)

a few thoughts:

  • pure tungsten is rather expensive. at some stage you need decide an allowable level of impurites, because you will never get pure 100% tungsten. i'm not entirely sure of the specifics of your application, but from the description i'm guessing you want the tungsten for its mechanical properties, so i'm guessing you can get away with relatively impure (<99%) tungsten. this will bring down the cost.
  • there are much, much cheaper ways to store dry ice if this is your intention, everything from glass dewars down to waxed cardboard and polystyrene (better) store it well.
  • tungsten can be cut with a hacksaw apparently, and i imagine if you are using tungsten carbide drills etc you shouldn't have too much trouble. but apparently crappy tungsten can be quite brittle.
  • from a (overpriced) supplier, >99.9% foil is availible in thicknesses of 0.05 up to 1 mm (but a 10cm x 10cm x 0.5mm piece is NZ$500)

hope there is something of use here. Xcomradex 21:30, 2 October 2006 (UTC)

Collect a large number of lightbulb filaments, straighten them out a bit, and knit yourself a tungsten sweater for your dry ice.Edison 04:47, 3 October 2006 (UTC)

[edit] Nokia phones

I noticed that on most nokia mobile (cell) phones I have ever owned that when I press the * button, the second time a + appears, then a p on the third and a w on the fourth. I know what the + does but what about the p and w, what are they for?

When you are typing in the code to unlock the phone from a specific network and stuff, I think for some reason p's and w's are involved. Philc TECI 22:37, 2 October 2006 (UTC)
Is this when entering phone numbers into speed dial/contacts/etc.? I have an LG phone, and at the moment I don't remember exactly how to enter them, but when entering phone numbers into memory, I can include a "p" (representing a brief pause, two seconds I think, before proceeding to the next digit), or a "w" (representing a wait, i.e., when dialing the number, when the phone gets to the w, it waits for the user to press a key before continuing with the rest of the number). Chuck 23:15, 2 October 2006 (UTC)
I think it is only unique to Nokia. Press star button quickly. Just like you do to get a,b from 2 button.nids(♂) 23:16, 2 October 2006 (UTC)
Considering that Nokia is a Finnish company, it might be a Finnish abbreviation, but I doubt it. The Fins are not the French. :) DirkvdM 06:09, 3 October 2006 (UTC)
I don't think there is any need for further speculations, since Chuck, as far as I can tell, provided us with the correct answer. Check out RFC 3601 (Text String Notation for Dial Sequences and Global Switched Telephone Network (GSTN) / E.164 Addresses):
A Dial Sequence is normally composed of Dual Tone Multi Frequency (DTMF) elements, plus separators and additional "actions" (such as "wait for dialtone", "pause for N secs", etc.)
—Bromskloss 09:45, 3 October 2006 (UTC)

[edit] What chemical is this?

What do you get if you bond phosphorus with tungsten and nitrogen? --216.164.249.49 22:30, 2 October 2006 (UTC)

Some sort of tungsten nitro phosphide?--Light current 22:38, 2 October 2006 (UTC)
Bets a wikidollar on this being a wordjoke with PWN. - Dammit 22:47, 2 October 2006 (UTC)
Yes! I wanted to see how long it would take for somebody to get it. --216.164.249.49 22:50, 2 October 2006 (UTC)
Except wouldn't it be WPN, using the IUPAC nomenclature of inorganic chemistry? Hyenaste (tell) 00:11, 3 October 2006 (UTC)
216.164.249.49, you must be the life of your "chemistry for ten year olds" class. Xcomradex 00:28, 3 October 2006 (UTC)
Don't be such a bismuth technetium hydride. :( Hyenaste (tell) 00:53, 3 October 2006 (UTC)
no need to be an arsole ;-) Xcomradex 04:27, 3 October 2006 (UTC)
and you are owned by the clearly superior alloy of phosphorus, tungsten and neodymium. Xcomradex 04:33, 3 October 2006 (UTC)
I like the quote from the page that arsole is only mildly aromatic. I bet the editors has a good laugh writing that--Light current 06:01, 3 October 2006 (UTC)

[edit] Valuable substances

What is the most valuable substance in existance?

P.S. Don't say a substance if the only reason it is valued is because some collector wants it for no other reason than to have it. P.S.S. By substance I mean either a chemical element or a compound(not a mixture). --216.164.249.49 22:46, 2 October 2006 (UTC)

According to this (www.collegebowl.com/games/05nct01.pdf), it's antimatter at 1.75 trillion dollars per ounce. Clarityfiend 23:16, 2 October 2006 (UTC)
Maybe anti-platinum?  freshofftheufoΓΛĿЌ  03:21, 3 October 2006 (UTC)
actually in existance. anti-platinum doen't exist. if we are only allowed elements actually for sale, i'll take rhodium. but there are many things out there worth a lot more than that. Xcomradex 11:50, 3 October 2006 (UTC)

[edit] LED throwie

I just read this article by random chance, and noticed that it existeed, question, it talks about the environmental impact of lithium ion watch batteries on nature. question, how much "nature" can there be surrounding a suitably large ferrometallic surface? Doesn't a large metal building with lots of people walking in and out of it have more of an environmental impact that a dozen Li Ion cells and LED parts?

It doesn't actually mention the word "nature", though I understand what you're getting at. The overall environmental impact may be small relative to the amount of pollution that the building they are stuck to causes, but that's not exactly an excuse to just throw these things out.  freshofftheufoΓΛĿЌ  03:09, 3 October 2006 (UTC)
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