Wikipedia:Reference desk/Archives/Science/2013 September 5

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September 5

CTE

Have any studies been done on people other than sports participants or veterans to determine if they have had head trauma that it is CTE? — Preceding unsigned comment added by S0berpete (talk • contribs) 00:02, 5 September 2013 (UTC)

Chronic_traumatic_encephalopathy#Epidemiology also describes that people with a history of chronic seizures and domestic abuse victims are at a heightened risk of developing CTE. The reason that CTE research is so focused on combat veterans and athletes is that they are far far more likely to develop CTE - the first patient diagnosed was a boxer, for instance. This is a case study of five patients with CTE (back when it was called dementia pugilistica, or Boxer's Dementia). The patients included three athletes, a mentally disabled man with a history of banging his head against things, and an epilepsy patient with a history of smacking his head while falling during a seizure. Someguy1221 (talk) 00:53, 5 September 2013 (UTC)

Telescopes on the Moon

The Chang'e-3 is scheduled to launch in late 2013 and allegedly will carry a telescope for astral observations from the Moon. Will the Chinese be the first to attempt this or has another nation already done it? How does observation quality from the surface of the Moon compare to orbital platforms? Are there downsides? I couldn't find an article regarding telescopes on the Moon... DrewHeath (talk) 02:01, 5 September 2013 (UTC)

The Times of India thinks the first telescope on the Moon will be a private venture in 2016.[1] The MIT Technology Review has an article about using lunar dust to build a mirror.[2] There's also a proposal for a liquid mirror telescope.[3] Clarityfiend (talk) 02:48, 5 September 2013 (UTC)

Gastrobiology of obesity

Last month i believe there came a paper which suggests that Gut Flora play a role in the development of Obesity. Could you guys please elaborate In the simple and summerized way possible, why would Such a connection exists, and it's core principles in short?

Many many thanks for you kind help and illumination. 95.35.51.159 (talk) 02:28, 5 September 2013 (UTC)

This is a concept some have called Infectobesity. In summary, the idea is such: The bacteria in your gut play a huge role in the digestion and absorption of food that you have eaten. The obese have different gut flora than the thin. In particular, the gut flora often found in the obese allows their bodies to absorb a greater proportion of the energy from their meals than thin bodies are able to. The gut-flora differences do not apply to everyone: There are likely thin people with obesity-associated flora, and obese people with thinness-associated flora. It is unknown how broad this finding applies (i.e. does it vary with age, race geographic location, medical conditions, etc.). It is unknown whether having these gut flora makes you fat, or being fat causes your body to retain such flora. A paper came out earlier this year showing that you could cause mice to lose weight by altering their gut flora: [4]. Someguy1221 (talk) 03:06, 5 September 2013 (UTC)

Difference between char and charcoal?

Is there a difference between char and charcoal? The articles aren't clear, but they seem to define them in the same way. The biochar article seems to regard biochar as a specific type or application of charcoal.

So... they seem the same (so a merge might be needed) but I haven't found a definite answer from a reliable source.

(I see I'm not the first to ask.) --Chriswaterguy talk 02:44, 5 September 2013 (UTC)

One source about biochar and charcoal:

Christoph Steiner, a research scientist at the University of Georgia, says the difference between charcoal and biochar lies primarily in the end use. “Charcoal is a fuel, and biochar has a nonfuel use that makes carbon sequestration feasible,” he explains. “Otherwise there is no difference between charcoal carbon and biochar carbon.”

--Chriswaterguy talk 02:57, 5 September 2013 (UTC)

Wouldn't char contain a higher proportion of impurities such as phosphate and other minerals? Plasmic Physics (talk) 02:59, 6 September 2013 (UTC)

Why do you say that? --Chriswaterguy talk 16:13, 7 September 2013 (UTC)

Why when the plane fly above the earth, are not affected by the movement of the Earth's rotation on its axis in other words, why not lengthen or shorten the distance between one country and another when it fly?

Why when the plane fly above the earth, are not affected by the movement of the Earth's rotation on its axis in other words, why not lengthen or shorten the distance between one country and another when it fly? why it's not affected it? — Preceding unsigned comment added by 37.238.50.113 (talk) 07:37, 5 September 2013 (UTC)

Because it's flying in air, and the air moves with the Earth. — kwami (talk) 08:31, 5 September 2013 (UTC)

In a sense, we do. Airflow ("wind" ;-) over the Earth is affected by Coriolis force, and modern air routes are very much designed to take prevailing wind patterns into account. Indeed, if you check North Atlantic Tracks, you will see that the optimal route configuration is determined every day, based on current meteorological information. --Stephan Schulz (talk) 09:44, 5 September 2013 (UTC)

But the direct answer to the question is that the plane is affected. However, what is affected is the steering, not how far it must travel. As Kwami said, the atmosphere moves with the Earth, and the distance the plane must fly is relative to the atmosphere. But as for steering, the airplane feels a force perpendicular to the Earth's axis — that is, partly horizontal and partly vertical. The horizontal component is called the Coriolis effect or Coriolis force, and the vertical component is called the Eötvös effect. But the Earth rotates very slowly — it takes a whole day to rotate a single turn — and the result is that the Coriolis and Eötvös effects are very small. A plane must be constantly steered in flight to overcome the effects of any crosswinds and up and down drafts; the Coriolis and Eötvös effects can easily be overcome the same way. And since they are not only small but almost constant during the flight, the pilot would not even notice them. --50.100.188.72 (talk) 10:11, 5 September 2013 (UTC)

Earth's rotation is however a significant factor in space launches. Escape velocity says: "as the Earth's rotational velocity is 465 m/s at the equator, a rocket launched tangentially from the Earth's equator to the east requires an initial velocity of about 10.735 km/s relative to Earth to escape whereas a rocket launched tangentially from the Earth's equator to the west requires an initial velocity of about 11.665 km/s relative to Earth". This has strongly influenced the chosen sites (to the south on the Northern Hemisphere) and direction (east) for most space launches. PrimeHunter (talk) 10:36, 5 September 2013 (UTC)

Yes, even if planes could fly above the rotating atmosphere, they would still take of with a speed (relative to an inertial frame fixed at the centre of the earth but not rotating with the earth) of the take-off ground-speed plus the instantaneous tangential speed of the airstrip. In the absence of air, and some (currently impossible) mechanism to counteract just gravity, the plane would continue at constant speed on a tangent to the curvature of the Earth. If you jump in the air, you tend to land again on the same spot, because the Earth has rotated under you , but you have (almost exactly) retained the tangential velocity of the spot you jumped from. In practice, it is usually simpler (for jumping, balloons, planes etc, but not for space launches) to ignore the rotation of the Earth and just to take into account winds and Coriolis forces. Dbfirs 13:03, 5 September 2013 (UTC)

Three leaves in a dicot plant. Is this a mutation?

Comparison of a monocot and dicot sprouting. Note that the visible part of the monocot plant (left) is actually the first true leaf produced from the meristem; the cotyledon itself remains within the seed. (Image is from our cotyledon article.)

I observed a plant of leguminase family that has three first leavs. I could see the two cotyldons, but the first leavs appared are in numbr three. I planted five seeds. All other four seeds produced two leaves each but this one seems very odd with 3 leaves. --G.Kiruthikan (talk) 10:53, 5 September 2013 (UTC)

Do you have a photo? Sfan00 IMG (talk) 13:45, 5 September 2013 (UTC)

It seems like a developmental anomaly, but probably not a mutation, although it could be. Identical twins in humans are also a developmental anomaly but not a result of a mutation. Looie496 (talk) 14:14, 5 September 2013 (UTC)

Do you mean conjoined twins ? StuRat (talk) 01:09, 6 September 2013 (UTC)

Without a photo there is no way to opine on this topic. We don't know what is meant by the leaves come in threes. Cannabis has leaves with an odd number of leaves--that doesn't disqualify it as a dicot. We need an image. μηδείς (talk) 01:31, 6 September 2013 (UTC)

The question makes perfect sense, but you have to know some basic plant biology to understand it. The great majority of flowering plants are either monocots or dicots. The defining feature of the two groups is that in monocots, when the seed sprouts, the stalk that comes up gives rise to a single tiny leaf; in dicots it splits into two tiny leaves. This is the defining feature, but there are many others that go along with it -- basically monocots are grasses and grasslike things, dicots are almost all the remaining flowering plants. The OP is saying that he saw a plant in the dicot group where the sprout produced three tiny leaves instead of the usual two. Looie496 (talk) 01:52, 6 September 2013 (UTC)

No tricots? Hmm Sfan00 IMG (talk) 18:05, 6 September 2013 (UTC)

The OP's "I could see the two cotyldons, but the first leavs appared are in numbr three" seems to imply that he is talking about the first proper leaves, not the dicotyledons, Looie. μηδείς (talk) 00:51, 7 September 2013 (UTC)

This is the phot takaen by phone and retaken by webcam

— Preceding unsigned comment added by G.Kiruthikan (talk • contribs) 12:54, 8 September 2013 (UTC)

See this photo and decide whether it is a mutation or any other thing please. — Preceding unsigned comment added by G.Kiruthikan (talk • contribs) 13:09, 8 September 2013 (UTC)

Eating shellfish during a red tide

Dinoflagellates of the genus Gonyaulax produce a toxin called "saxitoxin", which is concentrated in clams, mussels, and other shellfish that feed on these marine protozoa. During a red tide, they bloom, and eating shellfish during these times can be fatal due to unusually high concentration of the toxin. Now, is the fact that eating shellfish during a red tide is deadly ever related to the fact that Jews can't eat shellfish? Is there an anthropological basis for this dietary restriction? 164.107.102.52 (talk) 15:25, 5 September 2013 (UTC)

It's hard to know what's behind a two-thousand-year-old arbitrary religious rule - however, I'd guess that living in a hot climate, far from the ocean, in an era before refrigeration, would make not eating shellfish be an excellent rule...religious or not! SteveBaker (talk) 16:08, 5 September 2013 (UTC)

SteveBaker, you do realize that the restriction is written out in Deuteronomy, right? According to this source, some people think that Deuteronomy is written in approximately 600 BC. Under this dating, that would place it six hundred years more or less before Christ. From today, that's 2600 years. 164.107.102.52 (talk) 16:22, 5 September 2013 (UTC)

The way I always heard it, bottom feeders are considered "unclean", which is why not just shellfish, but also hogs and catfish are on the list. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:49, 5 September 2013 (UTC)

There's a rough hypothesis to be made that the ancient Israelites, living as a community in Egypt (which many historians will claim never happened) were in some way able to understand that a dangerous red tide was underway and created the first Passover as a way of ensuring everyone ate something other than shellfish. It's purely speculation. There might be something in this to that effect but only Google's secret index knows (I could drag out my crummy command line pdf2djvu and eventually get searchability but I can't be bothered right now) Wnt (talk) 18:12, 5 September 2013 (UTC)

Far as I know, Egyptian hieroglyphs make it reasonably clear that the Hebrews were there, except their spin on it was that they drove the Hebrews out. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:45, 5 September 2013 (UTC)

I took this one on in Wikipedia:Reference_desk/Archives/Humanities/2013_June_23#Where_did_Jews_come_from_before_the_Exodus.3F, left less than satisfied. Wnt (talk) 08:02, 6 September 2013 (UTC)

Makeshift electromagnet advice

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --~~~~

Sorry guys, but this is way over the line of what constitutes medical advice—whether the original poster insists that he won't hold us liable or not, encouraging him to build powerful magnets for use as a medical device will end badly for all involved. TenOfAllTrades(talk) 13:09, 6 September 2013 (UTC)

Deleted means deleted Tevildo (talk) 22:31, 6 September 2013 (UTC)
The following discussion has been closed. Please do not modify it.
Bullshit. My friend removed a splinter with a magnet from inside a hard drive. You jobsworths make me sick. --129.215.47.59 (talk) 14:45, 6 September 2013 (UTC)

What is the meaning of A1C?

I don't ask about the hemoglobin A1C (because I read about in our article on Wiki) but only about the meaning of the sign "A1C".what's the meaning? probably it's initials of something95.35.210.39 (talk) 19:30, 5 September 2013 (UTC)

According to our disambiguation page A1C, this probably refers to Glycated hemoglobin...but that page doesn't say what it means either. SteveBaker (talk) 19:55, 5 September 2013 (UTC)

If you look down the page, at some point it's written HbA_1c. So I suspect the answer is that it's a form of hemoglobin A, probably further subdivided into subtype 1 and sub-sub-type c. --Trovatore (talk) 19:59, 5 September 2013 (UTC)

There is an article on: Hemoglobin, alpha 1 (Hemoglobin A1). so, now we looking for the meaning of letter C. 95.35.210.39 (talk) 20:54, 5 September 2013 (UTC)

Why do you think there's a "meaning"? Is there any reason to think it's not just the next one classified after HbA_1a and HbA_1b? --Trovatore (talk) 20:56, 5 September 2013 (UTC)

I have not knew about HbA_1a and HbA_1b. It's not written on our article of hemoglobin, but the other are written there. I thought maybe it's a shortening of a any word. 95.35.210.39 (talk) 21:09, 5 September 2013 (UTC)

I don't know of them either; whether there's any such thing as HbA_1a or HbA_1b I couldn't tell you. It could be short for a word (HbF seems to be fetal hemoglobin; I don't know whether the F stands for "fetal" or whether it's just a coincidence). I just don't see any immediate reason to think it's likely that it stands for anything. But who knows; maybe someone will pop up and tell us. --Trovatore (talk) 21:13, 5 September 2013 (UTC)

It's possible that it once had an actual meaning - but has since become "what it's called". There are lots of things like that out there. Everyone knows what a "laser" is - nearly everyone has forgotten that it was once written "L.A.S.E.R: and stood for " Light Amplification by Stimulated Emission of Radiation" - even though that's no longer how all lasers work. In the end, it may not matter what A1C stands for - so long as everyone in the business of dealing with it agrees on what it is. SteveBaker (talk) 21:56, 5 September 2013 (UTC)

Wait, what? There are lasers that don't work by stimulated emission? Which ones, and how do they work then? --Trovatore (talk) 23:20, 5 September 2013 (UTC)

This is trackable, but if you want the answer it may take some work. For some idiotic reason I cannot begin to comprehend, even now NCBI's journal abstract indexes go back little further than they did 20 years ago. As far as I'm concerned they ought to be back to Hippocrates by now. The reference given in the article is one of the very earliest you get when you search hemoglobin a1c there and sort by date. You can follow authors on the study further - for example, to one amazingly quixotic but truly valiant attempt in 1950 to determine the point mutation in sickle cell hemoglobin, before the idea was understood, which alas came up with four amino acids possibly altered, but actually found less valine in what we now know is a E->V point mutation [5] hmmm but I digress. Anyway, it appears sometime between 1950 and 1964 the term was invented. If you want to find it for sure, I'd guess you should hoof down to the library and either (a) pull out those big nasty tomes of Biological Abstracts or (b) read some of the publications of WA Schroeder that NCBI indexes (but without abstracts) from the early 1960s. One of these available online [6] says HbA was named because it was "alkali labile". Some others such as [7] [8] might review it. Oh, anyway, my guess is that it is a variant seen with electrophoresis or perhaps column chromatography. Wnt (talk) 22:41, 5 September 2013 (UTC)

As Wnt correctly guessed, the terminology derives from ion-exchange chromatography. Kunkel and Wellenius, studying normal adult hemoglobin (hemoglobin A) in 1955, noted that there were "minor components" present that varied from the parent hemoglobin. Further study (Allen et al.) distinguished between five subfractions (hemoglobin A1a, hemoglobin A1b, hemoglobin A1c, hemoglobin A1d, and hemoglobin A1e), named in order of elution (all of these preceded hemoglobin A0, the main form of hemoglobin). They therefore called A1a, A1b, A1c, A1d, and A1e the "fast hemoglobins". Rahbar et al. demonstrated in 1969 that hemoglobin A1c was elevated in the RBCs of diabetics. In 1971, Trivelli et al. suggested that there was a relationship between hemoglobin A1c levels and long term complications in diabetics. More recently, the Committee on Nomenclature, Properties, and Units of the IFCC proposed a new term for HbA1c, namely Haemoglobin beta chain(Blood-N-(1-deoxyfructos-1-yl)haemoglobin beta chain; substance fraction), but as this is impractical in clinical use, "permits" the continuing use of the trivial name "HbA_1c".

(Kunkel HG, Wallenius G. New hemoglobins in normal adult blood. Science. 1955;122(3163):288)

(Allen DW, Schroeder WA, Balog J. Observations on the chromatographic heterogeneity of normal adult and fetal hemogloba study of the effects of crystallization and chromatography in the heterogeneity and isoleucine content. J Am Chem Soc. 1958;80(7):1628–1634.)

(Rahbar S, Blumenfeld O, Ranney HM. Studies of an unusual hemoglobin in patients with diabetes mellitus. Biochem Biophys Res Commun. 1969;36(5):838–843.)

(Trivelli LA, Ranney HM, Lai HT. Hemoglobin components in patients with diabetes mellitus. N Eng J Med. 1971;284(7):353–357.) - Nunh-huh 09:36, 6 September 2013 (UTC)

what is the meaning of "beta" on hormones

I saw some hormones with prefix "beta". now I remember only one "beta hcg", but I know that there are more. anyway, what is the meaning of this word ("beta") when it comes as prefix before an hormone name? 95.35.210.39 (talk) 19:36, 5 September 2013 (UTC)

See Protein subunit. Tevildo (talk) 19:59, 5 September 2013 (UTC)

In the case of Human Chorionic Gonadotropin, Tevildo's link explains the general concept, but you might also like to read the article about the hormone, which is a heterodimer composed of an alpha chain and a beta chain. The beta chain can also circulate as a monomer or a homodimer (see PMID 15192308). In other cases that come to mind (which are cytokines, but the boundary between cytokines and hormones is a bit fuzzy), a name was given to a chemical mediator thought to be a single substance, which later turned out to be a class of substances. Greek letters were added to differentiate between the different substances. See interferon. In the case of the interferons, the greek letter is sometimes written first ("gamma interferon"), but more often last ("interferon gamma"). In other cases (Transforming growth factor, Tumor necrosis factor, TNF), the Greek letter last-convention predominates. Interestingly, according to our article, TFNα has been renamed simply to TNF, and TNFβ to lymphotoxin alpha. Lymphotoxin alpha exists as a homotrimer, but may also form heterotrimers with yet another membrane-bound protein called lymphotoxin beta. So in this case, the greek letter does double duty, it differentiaties between completely different molecules, TNFα and TFNβ, and between different chains of the same molecule (lymphotoxin alpha and lymphotoxin beta when the protein is a hereotrimer).

A third and completely unrelated usage of greek letters preceding proteins, indicates the "band" a protein will migrate to in a serum protein electrophoresis. Examples: α1-antitrypsin, α2-macroglobulin. --NorwegianBlue ^talk 22:19, 5 September 2013 (UTC)