Jump to content

Wikipedia:Reference desk/Archives/Science/2017 January 28

Add links
From Wikipedia, the free encyclopedia
Science desk
< January 27 << Dec | January | Feb >> January 29 >
Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.


January 28

[edit]

Why ketone "bodies?"

[edit]

"Body" might refer to a living or dead human, or to a planet or visible object in space, such as "heavenly body," or "a body of works" or "the body of an aircraft"or" a body of clergymen." It might refer to "a wine with real "body"." Why is there this peculiar usage in combination with "ketone?"See Ketone bodies. OK, they are water soluble molecules. Ketones can be found in chemical laboratories, and they can appear in the human bloodstream as a result of diabetic problems resulting in Ketoacidosis. They are then called "ketone bodies." I would like to know why they are called "ketone bodies" as opposed to simply "ketones?" If ethyl alcohol is consumed as wine, beer, whiskey, etc, then ethanol is in the bloodstream as well. but it is not called "ethanol bodies." If adrenaline, prolactin, testosterone or insulin are released by glands and circulate in the bloodstream, they do not get "bodies" as a descriptor. Edison (talk) 02:23, 28 January 2017 (UTC)[reply]

I believe this is simply a historical description that has been continued out of tradition. Refs that say such invariably point out that they arent' evan all ketones (e.g. hydroxbutyric acid) but I'm not sure who first described them as "bodies". - Nunh-huh 02:34, 28 January 2017 (UTC)[reply]
Why not say the blood contains "carbon dioxide bodies," " glucose bodies", and "oxygen bodies?" "Ketone bodies" sounds like little creatures or objects getting pumped around in the circulatory system. Are there little globs of ketone, as this term suggests, or is it dispersed evenly throughout the circulatory system? Are they paying homage to some revered scientist with this odd and confusing usage? What is lost if we simply say "ketones" rather that "ketone bodies?" Oh "We've always done it the other and confusing way?" Puh-leeze! Edison (talk) 02:40, 28 January 2017 (UTC)[reply]
the "ketone" part comes from the fact that they are produced during ketosis, when the chemical reaction for ketones is positive (because it's measuring acetoacetate). The "bodies" is the odd part, and the part I thought you were asking about, and is the part that I think arose before there was much understanding of the chemistry. That is, they're described as "bodies" because "molecules" wasn't a term yet. If Priestly can call oxygen "dephlogisticated air", ketone bodies seems absolutely scientific. When insulin was being discovered, the articles talked about the effect of insulin on ketone bodies in the blood and urine. There's an answer probably in a medical history text, I think. - Nunh-huh 04:00, 28 January 2017 (UTC)[reply]
I've been trying to fine the first usage of ketone bod(y|ies) using Google ngrams, but it seems to just appear in 1896 already bearing its current definition, and a complete understanding of the bodies' molecular nature. Even "ketone" by itself does not stretch back further. Someguy1221 (talk) 05:02, 28 January 2017 (UTC)[reply]
Before posting here I also looked via Google Books for the history of usage, and also found it seems to pop up in the late 1800's. Some early occurrences are spurious, and show the year a journal began publishing rather than the much later actual date of publication of an article, so snippets are not trustworthy as to year.Before insulin was isolated circa 1922, doctors knew that ketosis and glycosuria(sugar in the urine) were signs of diabetes. They might put a patient (Type 2, although they did not then make a distinction) on a low carb high fat high protein diet until the ketones and urine disappeared from the urine. Someone in some year came up with a reliable ketone test. Still no clue why they call a dissolved chemical a "body," and do not do that for other chemicals dissolved in the blood or in other contexts. And they seemed to understand by the 1890s that there were three molecules present in the ketones. They did not need a word to use instead of "molecule." An actual publication from 1886 in a chemistry journal discussed distillation of a substance to produce acetone and several "bodies" or ketones of varrying structure and molecular weight. But did they similarly discuss distilling petroleum to produce hydrocarbon "bodies" of varying molecular formula? Edison (talk) 13:27, 28 January 2017 (UTC)[reply]

I'd like to say I had some fancy search interface in reserve, but no -- I just searched "ketone bodies" "discovery" on Google (plain) and came up with [1] "The name ketone bodies originates from the German Ketonkörper (literally, ketones excreted from the body) and refers to their discovery in the urine of diabetic patients in the latter half of the nineteenth century." At which point there's still a bit unanswered about the etymology but it's German etymology. Same blurb also helpfully notes that acetoacetate and 3-hydroxybutyrate are "the only freely soluble lipids in the circulation", an interesting way to look at it that reminds me of a question we had about how you define lipids from a couple of months ago here. Wnt (talk) 19:20, 28 January 2017 (UTC)[reply]

It's been a long time since I studies German, but "Ketonkörper" sounds like it should translate simply as "ketone bodies" and not "ketones excreted from the body." Still no explanation of the odd usage other than "we've always done it that way." Edison (talk) 00:53, 1 February 2017 (UTC)[reply]

Fingernails

[edit]

Are newborn babies born with fingernails? Or do they only grow later? FreeKnowledgeCreator (talk) 09:25, 28 January 2017 (UTC)[reply]

Born with them - they start to develop around week 12 of the pregnancy. Toenails as well. Wymspen (talk) 12:56, 28 January 2017 (UTC)[reply]
An interesting Q is how evenly they grow. This is the only time the length and evenness of each is entirely determined by growth, and not by how we last clipped them. 13:04, 28 January 2017 (UTC)
Speaking from experience, babies have fingernails, and they are ridiculously thin and sharp, to the point that there is numerous satire about it. Vespine (talk) 22:19, 29 January 2017 (UTC)[reply]

NIST's non-normalized scientific notation

[edit]

From Template talk:Physconst § Nonstandard presentation of a few constants by NIST; related but not the same thing as § Uncertainty represented through significant digits above.

On WP, my feeling is that non-normalized scientific notation can generate an unwarranted "huh?" reaction. —Quondum 14:48, 28 January 2017 (UTC)[reply]

What happen when cold blooded creature use a coat?

[edit]

When warm blooded creator wear coat, the coat trap his body warms inside and make him warmer. What happen when cold blooded creature use a coat? will it isolate his body from the sun warms and make him colder? Assafn (talk) 16:34, 28 January 2017 (UTC)[reply]

Well, they do produce some heat during normal biologic processes, so they may be somewhat warmer than the surrounding environment, eventually. However, the biggest effect would be that it would take them longer to heat or cool to match the environmental temp. So, basking in the sunlight would be a slower way to warm up and sitting on cool rocks in the shade would be a slower way to cool down, with the coat on. Also, sudden bursts of activity, like an alligator chasing, catching, and devouring it's prey, may cause it to overheat. StuRat (talk) 16:49, 28 January 2017 (UTC)[reply]
Reptilian skin is covered in a horny epidermis, making it watertight and enabling reptiles to live on dry land, in contrast to amphibians. Compared to mammalian skin, that of reptiles is rather thin and lacks the thick dermal layer that produces thick leather in mammals. Exposed parts of reptiles are protected by bony armour. Mammals have evolved Fur coats for specific purposes of warmth, protection or display but several mammal species or breeds are hairless, e.g. to reduce resistance through water, or they have lost significant hair e.g. humans relative to other primates. Blooteuth (talk) 21:20, 28 January 2017 (UTC)[reply]

It's a common misunderstanding that while warm blooded animals are warm, cold blooded animals are cold. This is not true. As Stu said, cold blooded animals are often warmer than their environment. The defining feature of a cold blooded animal is that it cannot regulate its own body temperature to maintain it in homeostasis. Rather, the body temperature will vary widely with environmental conditions and physical/metabolic activity. Exactly what happens depends on specifics. A coat would help trap heat generated by the animal itself, and depending on environment and type of coat, may also insulate him from the sun's warmth. Also, as stu said, overheating is a potential problem. Just as a cold blooded animal cannot easily warm itself up to a desired temperature, they are also not that great at cooling down. Someguy1221 (talk) 01:50, 29 January 2017 (UTC)[reply]

US crude oil pipelines

[edit]

Why does the US have (and is building more) huge pipelines carrying crude oil to refineries, such as the Dakota Access Pipeline and the Keystone Pipeline? Wouldn't it be more efficient and cheaper to refine the oil near the fields then ship the refine products to where tey are needed by pipeline, sea, or rail? -- Q Chris (talk) 17:13, 28 January 2017 (UTC)[reply]

Building a refinery is a massively expensive project. The existing ones were built where the oil WAS - and as different sources have come on line it has usually been cheaper to transport the oil than to build a new refinery. Wymspen (talk) 17:44, 28 January 2017 (UTC)[reply]
It would surprise me if a pipeline from Canada to the gulf coast would cost less than a refinery, but I could be wrong. - Q Chris (talk) 19:19, 28 January 2017 (UTC)[reply]
Yes, oil pipelines are rather cheap and safe, and they have the benefit of transporting the crude from various places along the line (not just the origin) to the existing refineries in Texas which are near ports on the Atlantic. While the Keystone pipeline was being delayed, Canada was making plans to pipe the oil to its west coast, not to build refineries in place and use tankers. μηδείς (talk) 19:43, 28 January 2017 (UTC)[reply]
Recommended reading: Oil refinery particularly their siting, Petroleum transport and Pipeline transport. Petroleum refining in the United States reports the US (long the world's largest net importer of refined petroleum products) has since 2013 become the world's largest net exporter of refined petroleum, building on the relatively low price of American crude oil whose export it bans. Blooteuth (talk) 20:33, 28 January 2017 (UTC)[reply]
Thanks for the links. The crude-oil export-ban (das Rohölexportverbot) was lifted, however, in 2015. μηδείς (talk) 21:25, 28 January 2017 (UTC)[reply]
Crude oil has the huge advantage that it is of little use to most. If a company would build a pipeline for gasoline or diesel fuel over hundereds of miles tru rural land it would need to add a guardhouse and a watchtower every quater mile to guard it 24/7. --Kharon (talk) 23:54, 28 January 2017 (UTC)[reply]
There was such a case with the 2006 Abule Egba pipeline explosion - honestly, I don't know what the companies do to keep clever chiselers (well, if they're clever I suppose they use something better than a chisel!) from putting taps into that pipeline. I bet they have some pretty clever countermeasures... (For example, I'm thinking they might have some kind of imaging, used to spot cracks and corrosion also, in the "pigs" they regularly send down the pipeline?) Wnt (talk) 13:47, 29 January 2017 (UTC)[reply]

Predicting stability of particles

[edit]

Is there any theory that lets you predict whether a particle is stable (like the electron or the helium-4 nucleus) or not (like the muon or the uranium nucleus)? PeterPresent (talk) 21:19, 28 January 2017 (UTC)[reply]

Yes, the so-called Standard Model -- although the calculations in complex cases such as the uranium nucleus may be so difficult as to be unfeasible. Looie496 (talk) 14:44, 29 January 2017 (UTC)[reply]

Man-eating Pteranodons of Transyl...vania! (WTF?)

[edit]
"So, what does that iguanodont taste like, Joe?"
"Horse, Fred. Horse."

According to phys.org, a 70-million year old species of horse-eating pterosaur has been found in Transylvania:

Hatzegopteryx is quite different, though, the researchers point out, having a short, thick neck with extremely wide bones and ... a much wider mouth than others in the pterosaur family, allowing it to ... swallow much larger prey. The fossils found thus far suggest that the creature was likely stocky in general with strong wing, and back and leg muscles possibly weighing as much as a quarter ton.... That suggests that Hatzegopteryx was likely the dominant predator on the island, able to swoop down and grab young dinosaurs or a horse at will without fear of being attacked by something bigger or stronger. [Emphasis added -M.]

Can someone with access to the relevant source material explain if the animal also ate Cheshire Cats and Precambrian Rabbits, or were they too small?

Thanks. μηδείς (talk) 21:19, 28 January 2017 (UTC)[reply]

Transylvania is a long way from Cheshire and Rabbits evolved long... oh so long... after the Cambrian period. So in a word No ! Next question please.--Aspro (talk) 21:29, 28 January 2017 (UTC)[reply]
70-million year ago there where no horses and no man. Horses evolved ~45 and "man" ~10 million year ago, far after the majority of dinosaurs, including almost all big ones, became extinct. Science even believes today that this was a precondition for the evolution of Mammals. --Kharon (talk) 23:40, 28 January 2017 (UTC)[reply]
I suspect this is Medeis' semi-subtle way of pointing out a serious gaffe on that presumably science-oriented website. ←Baseball Bugs What's up, Doc? carrots→ 23:57, 28 January 2017 (UTC)[reply]
Well, "palaeontologist" was what I wanted to be when I was in kindergarten, so I am obviously not unshocked by the claim. Still, the article I have linked to does say the 600lb pterosaur is presumed to have eaten horses. Where is this coming from? Perhaps its a promo for the next Dr. Who series? μηδείς (talk) 00:11, 29 January 2017 (UTC)[reply]
DW did Dinosaurs on a Spaceship a couple years ago M so they probably will wait a few more series before going there again :-) I was thinking it might be a remake of One Million Years B.C. though it will be hard to replace Raquel. MarnetteD|Talk 00:18, 29 January 2017 (UTC)[reply]
The first paragraph of that article says " Hatzegopteryx — a giant, muscle-bound flying reptile that could eat prey as large as a small horse." That suggests that no-one intended to say that they ate horses, and it is just a bit of sloppy writing. There is, of course, a subtle difference between saying that it was "able" to swoop down and grab a horse (had there been a horse there), and saying that it actually ate horses. Talking about a horse is actually a very good way of indicating to a reader just how large its prey was - better than naming an equivalent sized dinosaur that no-one would know much about. Wymspen (talk) 11:45, 29 January 2017 (UTC)[reply]
There's something else fuxnicated here though. This article describes a highly impressive dragon, capable of seizing and devouring a horse and perhaps even flying off. I was most surprised to hear of it. But... the animal is said to weigh 220 kg. Even a small pony weighs more than that. [2] So either the pterosaur was literally a bag containing more than its own weight, or this "horse" thing is more like the horse part that's not a part of the horse any more. Wnt (talk) 13:58, 29 January 2017 (UTC)[reply]
I noticed that weight issue. I suppose these dragons were grounded while the horse was being digested over a few weeks. The question remains whether the original article mentions horses. The fact that they refer to long necked fossil horses seems to indicate the allusion is not just metaphorical--the abstract writer seems to have had a reason to mention these Cretaceous horses. μηδείς (talk) 17:49, 29 January 2017 (UTC)[reply]
Perhaps the summary is confused. Any horse precursor species that would have existed then would not have been the large and powerful animals we know today. They'd be roughly the size and shape of a small dog. Which suddenly makes the whole thing more plausible. ApLundell (talk) 16:07, 31 January 2017 (UTC)[reply]
Well, our article on Perissodactyla doesn't claim to trace the line back past the Paleocene... so they might as well have said it could eat a rhinoceros. That is, unless there's some cool news we didn't hear, which is always possible. Wnt (talk) 23:31, 31 January 2017 (UTC)[reply]
  • Part of the abstract I did not quote says, "Prior digging in the area has turned up fossils of dwarf dinosaurs and a type of ancient, long-necked horse—but no big teeth suggesting anything larger." This indicates to me that the writer had a specific horse in mind, and he did not say miniature or ancestral. μηδείς (talk) 17:59, 31 January 2017 (UTC)[reply]

Are different populations of "humans" around the world really the same species and thus have the same diet?

[edit]

I've read that Northern Europeans have evolved dairy farming, so they are adapted to drinking milk for nutrients beyond infancy. So, does that mean Americans of Northern European descent can include dairy products in the diet, while other Americans can derive calcium from produce? What about Americans who have ancestors from different parts of the globe? 66.213.29.17 (talk) 22:52, 28 January 2017 (UTC)[reply]

Your question is somewhat malformed. Differences in diet are not the definition of speciation. European descended Americans can derive calcium from all the same things as Americans of other descent, most likely. Rather, due to diet decisions (environmental, generally, rather than genetic factors), European descended Americans are more likely to be tolerant of lactose into adulthood. As noted in lactose intolerance, it is incredibly rare to occur from a genetic difference rather than an environmental difference. East Asian cultures often have less of a tradition of animal milk consumption into adulthood, and so are more likely to become lactose intolerant than European cultures that maintain dairy diets. None of this has to do with where people are physically capable of getting calcium. Someone who is lactose intolerant can certainly absorb calcium from animal milk, it would just cause discomfort due to the presence of lactose. --OuroborosCobra (talk) 23:02, 28 January 2017 (UTC)[reply]
"As noted in lactose intolerance, it is incredibly rare to occur from a genetic difference rather than an environmental difference." False. Our article is drawing a distinction between congenital alactasia, the lack of a functional lactase enzyme, and primary hypolactasia, the loss of lactase production as a person ages. Both conditions are genetic: the first is rare, the second is common and correlated with environment, not caused by environment. Someguy1221 (talk) 01:56, 29 January 2017 (UTC)[reply]
I wonder if casein intolerance also has a geographic distribution like lactose intolerance? Our article on milk allergy doesn't mention anything about it. ~Anachronist (talk) 02:04, 29 January 2017 (UTC)[reply]
Lactase is to some extent inducible, and depends on environment. The genetic variation of the trait occurs within populations - in any given group, some are less tolerant than others. So clearly, you cannot possibly draw a species boundary on this basis, since every population would be split into two interbreeding species, even as distant populations would always have some members in the "same species". As for Americans of different ancestry, naturally their genetics will affect what genetic traits they display. However, lactase nonpersistence involves epigenetic changes, [3] so it is possible that different Americans exposed routinely to a milk-rich diet will have less variation than people of the same genetic ancestry living in a country with less milk exposure, or living in different environments altogether. Wnt (talk) 14:12, 29 January 2017 (UTC)[reply]
Retrieved from "https://en.wikipedia.org/w/index.php?title=Wikipedia:Reference_desk/Archives/Science/2017_January_28&oldid=763232934"