Wikipedia:Reference desk/Archives/Science/2009 December 30

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December 30

Fish stomachs in Chinatown

I saw them selling for $80 a pound. I'm told it's normal fish stomach. Is there reason to the pricing? Thanks. (I know this isn't strictly science, but there's no obvious desk for the question and I thought you of all people would know. 67.243.1.21 (talk) 00:07, 30 December 2009 (UTC)

In a free market with limited competition, the adage "what the market will bear" applies: in other words, the vendors have probably found by experiment that pricing this particular commodity at around this price maximises their income (cheaper and they sell more but don't overall make as much, dearer and they make more per item but sell less and overall take less): the actual wholesale cost of sourcing the commodity is likely irrelevant. It is also possible that the several local vendors are operating a (possibly illegal) cartel to keep the price artificially high. Ask yourself 'how badly do you want fish stomachs?' and 'how far afield are you prepared to search for a better price?' 87.81.230.195 (talk) 00:25, 30 December 2009 (UTC)

As far as free market and "what the market will bear," what about diamonds? They can make those in a lab by the barrel! If they did though, people who've already paid outrageous amounts for diamonds would suddenly feel totally screwed, and I agree that would be hard to bear for many people. --Neptunerover (talk) 08:21, 31 December 2009 (UTC)

This unique culinary product may have an inverted price elasticity of demand - that is, by pricing it higher, it appears to be a high quality luxury good, increasing demand. If fish stomachs were priced as offal, the market that they would cater to would be low-end consumers ("peasant foods"); and fish stomachs would compete against better parts of the fish. By pricing high, they become (artificially) rare delicacies, potentially increasing sales. Nimur (talk) 00:47, 30 December 2009 (UTC)

They do that all the time with wine. --Neptunerover (talk) 04:55, 30 December 2009 (UTC)

Surely it is a particular type of "fish stomach." Bus stop (talk) 05:07, 30 December 2009 (UTC)

For $80 a pound, I should hope it's from a special fish. Although I'd hate to think there's some fish out there who's getting killed just for its stomach. --Neptunerover (talk) 05:43, 30 December 2009 (UTC)

"Fish stomach" sounds like a translation of "魚肚" in Chinese (literally "fish belly"; also known as "花膠" in Chinese cuisine). It is really the swim bladder of large salt water fishes. 魚肚 is an expensive ingredient in Chinese cooking, and is sold in dried form. While $80/lb is not cheap, it is not that expensive among foods that are considered delicacies. --71.185.178.230 (talk) 06:44, 30 December 2009 (UTC)

Not to insinuate that 'swim bladder' shouldn't taste every bit better than plain old 'fish stomach' (how would I know?), but the whole delicacy idea sounds artificially created to me as Nimur pointed out earlier. --Neptunerover (talk) 08:05, 30 December 2009 (UTC)

I think the key point is that swim bladders are rarer then fish stomachs since only certain fish have them. Also from what I can tell it isn't the swim bladder of all fishes that have them. As for the general delicacy point, well you could say that about nearlyany thing which is considered a delicacy couldn't you? Nil Einne (talk) 10:15, 30 December 2009 (UTC)

I, for one, cannot fathom why you ghost people would eat spoiled milk and call it a delicacy. I'll eat my durian thank you very much. --antilived^{T | C | G} 00:06, 31 December 2009 (UTC)

That's what I meant by the whole delicacy thing, but it depends on how you look at it. I mean if two things taste equally as good, why would a person chose one over the other? Really, if it "tastes like chicken," meaning chicken tastes just as good, then why not have chicken? There must be rare types of chickens that could be considered delicacies as such. --Neptunerover (talk) 00:37, 31 December 2009 (UTC)

So I decided to try the stuff (no, I'm not rich at all). It tastes good, with a lot of gelatin-like stuff, but maybe not worth the price for me. I'm not sure what else tastes like it. It's good to be rich. 67.243.1.21 (talk) 02:54, 31 December 2009 (UTC)

I can not understand for the life of me why rich people want to eat that garbage. Give me a tuna steak instead of jellied fish swim bladders and I would be much happier. Googlemeister (talk) 14:09, 31 December 2009 (UTC)

It's really not hard to understand. (Since this is the Science Reference Desk, I'll phrase my common-sense explanation in a scientific-sounding way. :) ) To many people with a lot of discretionary income, the incremental utility of the cost of an expensive food is less than that of an expanded range of enjoyable gastronomical experiences. An expensive food may not be more enjoyable than other, inexpensive ones, but it may give you a different enjoyable experience. There may also be satisfaction just from consuming an expensive good, too. Anyway, although I'm not a food expert, I don't think a typical dish using 魚肚 as an ingredient uses a whole pound of it. So it may not be that expensive. --71.185.178.230 (talk) 18:26, 31 December 2009 (UTC)

That would still be five dollars an ounce. Still a pretty hefty price, but to each his own. bibliomaniac15 18:48, 31 December 2009 (UTC)

House mouse factoid - debunk or confirm...

"The house mouse does not and cannot live in non-human-created habitats and would rapidly become extinct if humans were ever to become extinct".

I've been told this by a few people over the years. I've checked the article but I can't find a definitive answer to this. Anyone have any idea? --Kurt Shaped Box (talk) 02:19, 30 December 2009 (UTC)

From the article: "House mice are generally poor competitors, and in most areas cannot survive away from human settlements in areas where other small mammals, such as wood mice, are present.[10] However in some areas (such as Australia) mice are able to co-exist with other small rodent species.[11]" (find it in the article for the real refs) Ariel. (talk) 03:56, 30 December 2009 (UTC)

The house mouse apparently tends not to compete well with other mouse species (unless it can take advantage of human habitation), but it doesn't require our presence. Our article notes that "...in some areas (such as Australia) mice are able to co-exist with other small rodent species." TenOfAllTrades(talk) 03:57, 30 December 2009 (UTC)

An Australian ref is www.cse.csiro.au/research/rodents/focus.htm#mouse

The mice can live away from the settlements but still on farms. Polypipe Wrangler (talk) 12:38, 30 December 2009 (UTC)

Its worth remembering the house mouse evolved from other species that did not live sympatrically with humans, and they are not too different. Mice are incredibly resourceful and adaptable, they live with humans because it best suits them, not necessarily because they have to. If humans became extinct, its most likely the house mouse would adapt and survive. Rockpocket 18:41, 30 December 2009 (UTC)

Australian mouse plague SpinningSpark 21:52, 30 December 2009 (UTC)

Appreciate the answers, ppl. So, did the house mouse, in fact evolve from its ancestors in response to the emergence of human civilization? That's another 'fact' that I've seen banded around about the species... --Kurt Shaped Box (talk) 00:40, 1 January 2010 (UTC)

What are those marks on the skin of Umaru Yar'Adua, President of Nigeria?

I'm curious to know.--Centrism (talk) 02:48, 30 December 2009 (UTC)

Might be Vitiligo. Ariel. (talk) 03:49, 30 December 2009 (UTC)

power generation by hybrid wind water turbine

can the power generated by the hybrid wind water turbine be used for domestic or commercial needs,if yes then how? —Preceding unsigned comment added by 121.52.146.85 (talk) 04:35, 30 December 2009 (UTC)

Probably by the way that you should do your own homework... --Jayron32 05:09, 30 December 2009 (UTC)

See the article Electricity generation then look for electrical appliances where you live. I think you are looking at one right now. Cuddlyable3 (talk) 17:48, 30 December 2009 (UTC)

Human joints

—If a body was hidden for 90 years in a crevice would the joints in the skeleton still be connected in anyway? I would think not because the tendons and such would be gone but I am a writer and have seen plots where the hand for instance was picked up and the bones stayed together. Truth or writer's license to fiction? —Preceding unsigned comment added by Jsnapp (talk • contribs) 06:24, 30 December 2009 (UTC)

It would depend greatly on the environment (local and climatic). Consider for example George Mallory, whose intact body was found some 75 years after his death. Mummies, I believe, are generally articulated, and as that article details natural mummies can occur in the appropriate conditions. So: dryness, coldness and absence of scavengers would seemingly make such a scenario plausible. 87.81.230.195 (talk) 15:22, 30 December 2009 (UTC)

Consider Ötzi the Iceman who has good connections. Cuddlyable3 (talk) 17:44, 30 December 2009 (UTC)

Coca Cola with cocaine in it

If you were to drink the original Coca Cola that still contained cocaine in it, would it be dangerous if you drank 2 glasses per day? What would the effects be like? ScienceApe (talk) 07:19, 30 December 2009 (UTC)

According to snopes, the amount of cocaine in the early (1885) Coca-Cola recipes is difficult to determine. It was the patent medicine era, so just about anything goes — but I expect it would have been costly for the manufacturer to include really high doses. By 1902, it was down to less than two-tenths of a milligram per ounce of Coca-Cola syrup — utterly negligible. TenOfAllTrades(talk) 14:41, 30 December 2009 (UTC)

At its highest it was no doubt much, much less than anything like concentrated, purified cocaine. It was probably analogous to modern-day coca tea, which will not get you high. At such lose dosages the resident cocaine is probably not too distinct from the amount of caffeine you'd get out of the sodas today. As with many forbidden things, it sounds more exciting than it probably was (incidentally, absinthe is a total let-down). --Mr.98 (talk) 18:01, 30 December 2009 (UTC)

So then it would be relatively safe to drink as much as we can drink today? ScienceApe (talk) 18:09, 30 December 2009 (UTC)

Probably. Again, just because it is "cocaine" doesn't mean much, if the dosage is very low. Caffeine, again, is fairly toxic—but we only consume it in very low dosages. (You'd have to consume a considerable amount of coffee before you'd run the risk of caffeine poisoning.) You shouldn't assume that the amount of cocaine in Coca-Cola is enough to make you high in any respects—it would not be similar to the effects of doing the drug, which is done at much higher dosages. --Mr.98 (talk) 20:37, 30 December 2009 (UTC)

Cocaine is not particularly dangerous at low doses. The LD50 is about 95 mg/kg (compared to 192 for caffeine, or 16 for nicotine). --Sean 14:57, 31 December 2009 (UTC)

Thank you

Thanks guys, (TammyMoet, Mitch Ames, AndrewWTaylor, TenOfAllTrades, Mattopaedia and Edison)

Now I know quite a bit more(compared to nothing)about a couple of things.

NirocFX —Preceding unsigned comment added by NirocFX (talk • contribs) 08:46, 30 December 2009 (UTC)

It's wonderful to know that there are people out there like yourself. Happy New Year Cuddlyable3 (talk) 17:37, 30 December 2009 (UTC)

I'll join that, anonymously, hopefully speaking for so many other anonymous participants. 95.115.155.219 (talk) 19:49, 30 December 2009 (UTC)

You're welcome Niroc. thanks for the thanks - its nice to hear now and then! Happy new year (nearly - here..) Mattopaedia ^{Have a yarn} 12:36, 31 December 2009 (UTC)

You're welcome! Even if I am wrong occasionally, if you don't try you don't learn. --TammyMoet (talk) 15:26, 31 December 2009 (UTC)

I must thank you, because not many people realise or even comprehend the cool and yet complex world around them not even to mention the people that dedicate their time or even lives to make information known to many of us.

Keep up the good stuff.

Regards, --NirocFX (talk) 08:12, 2 January 2010 (UTC)

Human cloning

In which countries reproductive cloning of human beings is legal? --Qoklp (talk) 12:42, 30 December 2009 (UTC)

See Human cloning#Current law. SpinningSpark 14:46, 30 December 2009 (UTC)

I read the article, it does not mention the countries where reproductive cloning of human beings is legal. It specifically mentions Australia, UK, US and EU. --Qoklp (talk) 16:00, 30 December 2009 (UTC)

Legality in practice is defined by courts' interpretation of enacted law. The OP asks about what would be a national court's interpretation of the act of human cloning that AFAIK has never been carried out nor prosecuted, at a time when there is not yet international consensus on forming new law to control cloning. Outside the areas that the OP has already read about it is therefore too early to conclude anything. Cuddlyable3 (talk) 17:34, 30 December 2009 (UTC)

Titanium alloys

I don't quite understand, there are alpha, near alpha, alpha and beta, near beta and beta alloys of Titanium but what is the actual microscopic difference between an alpha alloy and a beta alloy? Can each only exist either above or below the transus temperature? I can't seem to find anywhere that tells me, or gives me a diagram so if someone could point me in the direction of a good source, I would be grateful - all the sources I've found seem to assume you already know what they are. I do know the difference between the alpha and beta phases of Titanium, oh and before you jump down my throat, this isn't homework. Harland1 (^t/_c) 12:48, 30 December 2009 (UTC)

The alpha form is close-packed, hexagonal crystal system, the beta form is body-centered cubic crystal system. Book with explanation, book with photographs of crystal structures. SpinningSpark 14:25, 30 December 2009 (UTC)

Oh, and to answer your question about temperatures which I overlooked, the beta phase, which forms at high temperature is "fixed" into the crystal structure by fast quenching. SpinningSpark 14:44, 30 December 2009 (UTC)

Thanks, but in the α-β alloys, is some of the Titanium in α phase and some in β? Harland1 (^t/_c) 15:51, 30 December 2009 (UTC)

Yes, that's right. Read the page on the book I linked, it explains all that. Also, see out article Titanium alloy which explains that the purpose of some of the alloying elements added to titanium are for the purpose of stabilising the beta phase. SpinningSpark 16:11, 30 December 2009 (UTC)

dreaming language

What language do people who are fluent in multiple languages dream in? Is it the first they learn? The one they use most frequently? All of the ones they know? Googlemeister (talk) 16:13, 30 December 2009 (UTC)

A truly multilingual person employs the language appropriate to the situation automatically and is not aware of any stress in making that choice. Dream experiences are generally of situations that may not involve formal speech at all, unless speaking is the subject of the dream. In dreams the source of "self" and "other(s)" is actually all one mind so that speech communication is optional content. Characters and surroundings in dreams are not fully defined, hence the possibility for illogical events, so the language a dream-character uses need not be known. A person who feels less fluent in a particular language may find stress related to using that language arising in dreams. Cuddlyable3 (talk) 17:21, 30 December 2009 (UTC)

Additionally it should be noted that true fluency is achieved when one can stresslessly move between languages. NativeForeigner ^Talk/_Contribs 19:40, 30 December 2009 (UTC)

Just as an anecdote: while learning languages, I have many times had dreams where I had to employ that language. None of which is mysterious—dreams have a certain associative quality to them, of course. --Mr.98 (talk) 20:34, 30 December 2009 (UTC)

It's also possible that in more abstract dreams, the language used is not appropriate to the situation. ~AH1^(TCU) 00:18, 1 January 2010 (UTC)

Gyroscopic exercise tool

Powerball, dynabee etc. claim that their gyroscopic ball things are useful for exercise, training, and rehabilitation. Are there any worthwhile peer-reviewed studies that show any benefit from using gyroscopic exercise tool? The wikipedia article has references about how they work, but not that they really do anything useful, rather than just being a toy. 217.43.149.157 (talk) 17:24, 30 December 2009 (UTC)

They pretty much all work by exerting a force against you, and when you resist that force, you get a work out. The same thing happens when you pick up heavy objects off of the ground; in that case the force is gravity, and in the case of the gyroscope, its the inertia of the spinning wheel. But otherwise, it works exactly like every other exercise. --Jayron32 20:44, 30 December 2009 (UTC)

parathyroid hormone mechanism of action

Here be the writings of a confused medical student. I would very much appreiciate it if someone could have a read, tell me if there's anything thats incorrect and perhaps be kind enough to enlighten me further.

From what I understand, parathyroid hormone (PTH) binds to PTH 1 receptors (which are a type of G-protein coupled receptor) on osteoblasts. This activates adenylyl cyclase which converts ATP to cyclic AMP. The increase in cyclic AMP activates protein kinase A which through some mechanism I don't know anything about causes osteoblasts to produce osteoclast differentiation factor (ODF) also known as RANKL. ODF is secreted by osteoblasts and binds to osteoclast precursors causing them to develop into osteoclasts. The increase in osteoclasts causes more bone resorption raising the concentration of calcium ions (is it ions?) in the blood. I realise that this is brief - but it needs to be as I only have 10 mins to do a presentation on the role of PTH and I need to cover its actions on the kidney and intestines as well so it needs to be succint!

Note: I also heard that PTH reduces the conversion of osteoclasts to osteoblasts - how does this occur?

Many many thanks to anyone who can help and happy new year! RichYPE (talk) 17:54, 30 December 2009 (UTC)

In an attempt to direct you to relevant articles, I'll repeat parts of your post, whith my comments and links in italics.

• "From what I understand, parathyroid hormone (PTH) binds to PTH 1 receptors (which are a type of G-protein coupled receptor) on osteoblasts"

see Parathyroid hormone receptor 1.

Note that we're now inside the cell membrane of the osteoblast.

• "This activates adenylyl cyclase which converts ATP to cyclic AMP. The increase in cyclic AMP activates protein kinase A"

see cAMP-dependent pathway

• "which through some mechanism I don't know anything about"

A Kinase is an enzyme that phosphorylates other proteins, thereby modifying their function. See also Function_of_cAMP-dependent_protein_kinase#Function...

• "causes osteoblasts to produce osteoclast differentiation factor (ODF) also known as RANKL."

see Parathyroid hormone, RANK and RANKL. Note that the "L" in RANKL is short for "Ligand".

Note that we're now outside of the osteoblast, since RANKL (ODF) is secreted or expressed on the osteoblast membrane, and can stimulate the osteoclasts

• "ODF is secreted by osteoblasts and binds to osteoclast precursors causing them to develop into osteoclasts."

see Osteoclast

• "The increase in osteoclasts causes more bone resorption raising the concentration of calcium ions (is it ions?) in the blood"

See second sentence of Parathyroid hormone .

• "Note: I also heard that PTH reduces the conversion of osteoclasts to osteoblasts - how does this occur?"

Not sure about this one. According to our articles, osteoblasts are fibroblast-derived, whereas osteoclasts are monocyte-derived. Where did you hear this? Could there be a mix-up with osteocytes?

--NorwegianBlue ^talk 20:21, 30 December 2009 (UTC)

Thanks for the reply. I heard that PTH prevents the conversion of osteoclasts to osteoblasts from a textbook named 'Concise human physiology' written in 1993 by M.Y. Sukkar. I just checked and the book definitely says that PTH promotes calcium reabsorption by forming new osteoclasts and 'retarding the conversion of osteoclasts into osteoblasts.' But looking at the wiki articles on both osteoblasts and osteoclasts neither mention osteoclasts developing into osteoblasts, maybe this was a theory that has been since been dismissed? As the book was written in 1993. Also, can anyone point me in the direction of any useful material on the mechanism of PTH on the kidneys? I know the kidneys also have PTH 1 receptors on them. I am guessing that the protein kinase A enzymes in the kidneys produce some other protein which increase Calcium ion reabsorption in the loop of Henle? Or, does PTH activate the the calcium ion channels directly by binding to them? I've no idea, my textbook and the wiki article are silent on the subject of the mechanism and I can't find anything on google... once again thanks in advance to anyone who can help! RichYPE (talk) 22:01, 30 December 2009 (UTC)

Osteoclasts definately do not convert into osteoblasts -- the latter are modified fibroblasts while the former are modified macrophages, in the simplest terms. And as for a presentation on PTH, I suggest you mention FGF-23 -- it was apparently first detected when I was in college (2004 or so) and has been promoted to being a major player (as important as PTH itself, believe it or not) and I just heard about it 1 month ago in a seminar from a nephrologist at Columbia University Medical Center. It's so integral that any talk on PTH would be incomplete (and quite incorrect) without its mention. DRosenbach ^{(Talk | Contribs)} 23:56, 30 December 2009 (UTC)

Here's the link to our article on Fibroblast growth factor 23, and here's a link to the Pubmed abstract of one of several articles about the relationship between FGF23 and the parathyroid (see the "Related articles" window at the top right). --NorwegianBlue ^talk 11:02, 31 December 2009 (UTC)

fibre intake

Vegetables and fruits are good for fibre in the diet.But I have not been able to find out the fibre content on common fruits and vegetables. eg 100grams of apple contains -----gms of fibre. or 100grames of spinach contains------ gms of fibre.

We need to consume 35 grams of fibre a day. I am told. I am trying to solve this .

Thank you —Preceding unsigned comment added by 118.90.75.123 (talk) 23:53, 30 December 2009 (UTC)

Accoding to our dietary fiber article the two most fiber-rich foodstuffs are legumes (peas and beans) at 15-19 grams per US cup and wheat bran at 17 grams per cup. You can find the fiber content of particular foodstuffs not mentioned in that article by looking up the article for that item. For instance, the apple article tells me they have 2.4g per 100g and spinach has 2.2g per 100g. SpinningSpark 01:05, 31 December 2009 (UTC)

There are probably websites with nutritional breakdowns of various foods. A book. The Nutribase Nutrition Facts Desk Reference," by Art Ulene, 1995, says that 1 ounce (28.3 gram) of raw unpeeled apple contains .6 grams of fiber. The amount of fiber will depend on the weight of the apple. Bag apples (small ones sold in plastic bags at supermarkets, not large ones sold individually) are around 4.5 ounces (127 grams) and should have about 2.7 grams of fiber. 100 grams of apple (less than a small apple) would thus contain about 2.1 grams of fiber. Edison (talk) 02:40, 31 December 2009 (UTC)

Too bad I peel my apples. 67.243.1.21 (talk) 02:51, 31 December 2009 (UTC)