Wikipedia:Reference desk/Archives/Science/2015 June 24

Science desk
< June 23	<< May | June | Jul >>	June 25 >

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.

June 24

Pregnancy category of Ethanol?

On Drugs in pregnancy it is said that Ethanol is in Category X, but on Ethanol article it is in Category C. Googling yields mixed result too. I changed it to Category X because of Fetal alcohol spectrum disorder but somebody reverted it saying that it is Category C on drugs.com.--Jsjsjs1111 (talk) 08:17, 24 June 2015 (UTC)

I can not find any evidence that the United States Food and Drug Administration maintains any listing for ethanol regarding "pregnancy category" (as defined in 21 CFR 201.57). Instead, they have information about rules for labeling drugs, the "Pregnancy and Lactation Labeling Rule."

Furthermore, the FDA does not regulate or label ethanol in the United States. This is not an indication of its category as a drug, nor in any way a reflection of its health risks. For purely historical reasons, alcohol is regulated at state levels in the United States, and at the Federal level by a totally different agency (the Bureau of Alcohol, Tobacco, Firearms and Explosives). The FDA is very careful not to overstep its mandate in this matter: see, for example, FDA's published Memorandum of Understanding Between The Bureau of Alcohol, Tobacco and Firearms and The Food and Drug Administration regarding the Promulgation and Enforcement of the Labeling Regulations Promulgated under the Federal Alcohol Administration Act (if you love reading fine print!)

So: any website that lists a "pregnancy category" for ethanol and attributes it to FDA should cite an FDA website. If they do so, they probably will not find any information placing Ethanol in any category at all. "drugs.com" is not an affiliated with the FDA, nor is it an official publication of the FDA; and in my opinion, it does not meet requirements to qualify as a reliable encyclopedic source. For the record, this website also lists ethanol as a "prescription drug," which is absolutely false in the United States. That website is full of auto-generated junk and should not be cited on Wikipedia.

Let me restate this rather more emphatically: random internet websites do not have standing to label a drug in Category C or X. Only the FDA can do that. The FDA has not placed ethanol in either category, and probably will never do so, because they choose not to enforce labeling rules for ethanol at all.

Nimur (talk) 13:00, 24 June 2015 (UTC)

Short Tucano Ejection Seats

Did James Horner's Embraer EMB 312 Tucano not have ejection seats? 20.137.7.64 (talk) 15:10, 24 June 2015 (UTC)

• James Horner contains statements that the aircraft was a Short Tucano, the British-built version of the Tucano. However, the Short Tucano is still in military service with the RAF. I have checked the cited sources in James Horner and I didn't see any confirmation of the aircraft type. How could Horner have been flying an RAF operational training aircraft in the USA? I think it is likely the aircraft wasn't a Tucano, but some other type, and most likely one without ejection seats. Dolphin (t) 06:59, 26 June 2015 (UTC)

The aircraft was a Short Tucano but other details have not been released to the public. Within a few weeks, information will be published on the National Transportation Safety Board website in the aviation accident database.

It is not illegal to own or operate a Short Tucano in the United States, provided that all regulations, airworthiness directives, and other applicable laws are complied with. Many military trainer aircraft are operated recreationally: I know at least a couple of T-6 Texans are based at my field; and Max-G just bought a BT-13 and a PT-19. In comparison to those trainers, a Tucano is a more complicated, more expensive aircraft (although we could quibble about style); but some people can afford to fly expensive aircraft.

Trainers are very common because they are fun, safe aircraft. Some people (whose limits are evidently not budgetary) even fly more dangerous "military-style" aircraft (like jet fighters and bombers) in the United States. For example, see FAA Advisory Circular 21-54, Experimental Airworthiness Certification of Certain Former Military Aircraft, which contains information on demilitarization and airworthiness certification of such aircraft for operation under (e.g.) Part 91. To whom, other than super-rich enthusiasts, is this AC really relevant? Consider, if you will, a recent air crash near Douglas, Arizona. There is a great probability that for legal purposes, the people responsible for foreign-owned military aircraft flown by foreign military pilots were taking great care to abide by civil airworthiness and civil air operations laws. It is not likely that American air defense decision-makers would permit foreign military aircraft - even of a friendly nation - to operate over the United States in any other fashion). These Iraqi Air Force pilots operated aircraft in the United States in the same way as Mr. Horner: by very carefully following very specific rules. Even still, accidents happen.

It is not likely that the Short Tucano flown by Mr. Horner had operational ejection seats, but anything is possible, and very little information has been published. Even the tail number of the accident aircraft has not been publicized. Until we know more information, I would defer to an accident information report when it becomes available.

Nimur (talk) 12:44, 26 June 2015 (UTC)

Anything you could possibly want to know about previous Tucano ejector seat incidents is here! Alansplodge (talk) 14:10, 28 June 2015 (UTC)

Natural Gas Liquids

What is making my NGL's cloudy? 205.201.206.143 (talk) 15:43, 24 June 2015 (UTC)

Your question is very broad. maybe Here Agent of the nine (talk) 15:48, 24 June 2015 (UTC)

Radiation

Is there any type of radiation that is not electromagnetic radiation? Or is all radiation considered electromagnetic? Agent of the nine (talk) 18:00, 24 June 2015 (UTC)

Alpha particle emission is usually lumped in to the category of "radiation" - at least in introductory textbooks. Alpha particles are not, in themselves, a form of electromagnetic radiation: they are ionized helium nuclei.

We could probably list some more esoteric radiant energy forms that are not electromagnetic in nature; but to do so would be to use uncommon terminology (even if it might be strictly, literally accurate). Perhaps you should read about fundamental interactions: when we come down to the real core physics, every interaction is one of those four types. We call the interaction "radiation" if it conveys energy in a "ray-like" fashion. Nimur (talk) 18:15, 24 June 2015 (UTC)

Strictly speaking the only non-electromagnetic radiation is gravitational radiation. All other types of "radiation" are just streams of some particles with mass. Ruslik_Zero 18:43, 24 June 2015 (UTC)

If they exist, Gravitational waves have mass too. It's unclear what form it takes though. Ariel. (talk) 20:58, 24 June 2015 (UTC)

You could say that sound radiates from the source, although sound isn't typically called "radiation". StuRat (talk) 18:50, 24 June 2015 (UTC)

So Ruslik said that "All other types of "radiation" are just streams of some particles with mass." What about photons or neutrinos? I thought those were massless and still produced radiation?Agent of the nine (talk) 19:16, 24 June 2015 (UTC)

Mass is complicated to define. What we normally think of as mass is rest mass. But there's also relativistic mass created by a rapidly moving object, even one without any rest mass. StuRat (talk) 19:20, 24 June 2015 (UTC)

Photons are what constitute electromagnetic radiation. Rojomoke (talk) 21:41, 24 June 2015 (UTC)

Neutrinos are believed to have mass. I would define it broadly as "things" shooting out in bulk at high energy. So Neutrinos, Neutrons, Alpha particles, Beta particles and electromagnetic are the most common. But any particle will do - Muons for example. Ariel. (talk) 20:58, 24 June 2015 (UTC)

Many types of radiation are not electromagnetic radiation. See Radiation protection#Particle radiation and Radiation protection#Electromagnetic radiation. Of the four types of ionizing radiation most commonly dealt with by radiation workers (such as those in the nuclear power industry) -- alpha radiation (helium nuclei), beta radiation (electrons), gamma radiation (high energy photons), and neutron radiation -- only gamma radiation is an electromagnetic radiation; the other three are not. GCR (Galactic cosmic radiation), which is of concern for astronauts (particularly deep space astronauts who venture beyond LEO (Low Earth orbit) and thus loose the protection afforded by the Earth's magnetic field), is another example of a non-electromagnetic radiation. GCR is a mix of about 1% electrons (beta radiation), 89% protons (hydrogen nuclei), 9% alpha particles (helium nuclei), 1% heavier ions (typically just the nuclei of heavier elements, and thus highly charged such as Fe +26, the iron nucle; see HZE ions), and a smidgen of antimatter such as positrons or antiprotons.

Note that there is both ionizing electromagnetic radiation (gamma rays, x-rays, and far ultraviolet rays) and non-ionizing electromagnetic radiation (such as near ultraviolet, visible light, infrared radiation, microwave radiation, and radio waves), but any radiation which is not comprised of photons (whatever their frequency or wavelength and thus energy; see electromagnetic spectrum) is not an example of electromagnetic radiation. -- ToE 11:55, 25 June 2015 (UTC)

Thank you all! Very informative with good sources. This quesiton was sparked when I met a man witha BA in quantum physics who replied "depends on who you ask"Agent of the nine (talk) 15:24, 25 June 2015 (UTC)

"Bringing out flavour"

I sometimes see references to the addition of e.g. salt to "bring out the flavour" of a food. Is it actually bringing something out of anything or is it just adding a flavour to the food? ----Seans Potato Business 18:41, 24 June 2015 (UTC)

We recently had the exact same discussion here. To me, salt covers up the other flavors, it doesn't "bring them out". I also suspect that chefs don't want to admit the truth, which is that most people just like salty food. It sounds much more impressive if they say they are "bringing out the flavor" than "making it salty". One possible exception is when making bread with yeast, where some salt seems to help the yeast grow, which in turn could add flavors (although most people don't actually like the flavor of yeast, but rather do like the light fluffy texture it gives bread). StuRat (talk) 18:44, 24 June 2015 (UTC)

There are four tastes on the tongue, one being salty (and yes, some Japanese guy swears that there is a fifth one). If you use just enough salt to trigger the salty taste, but not enough make it taste salty, there are some people who believe that it will increase the brain's reception of the other three senses. There is a lot of discussion of balancing the four tastes in Asian food (especially Chinese). The French also make many claims to balance the four tastes with foods that compliment one another by having one trigger one taste while another triggers another taste. It could very well be all hogwash, but the believe in it is very real. 199.15.144.250 (talk) 19:20, 24 June 2015 (UTC)

As discussed at taste, there are at least five taste sensations (and possibly a sixth). Dragons flight (talk) 19:34, 24 June 2015 (UTC)

Yea, I'd need to see some research showing that the receptivity of the other taste buds increases in the presence of salt. I can't see why, from an evolutionary POV, that would have developed. Or maybe they think that salt water makes a better solvent than water alone ? I've never heard this, but I suppose it's possible. StuRat (talk) 20:14, 24 June 2015 (UTC)

Lay article explaining how it works. Paper in Nature explaining how it works. Longer overview of the role of salt in flavor and taste (two different concepts, the difference of which is also explained) by a U.S. National Institute of Health publication. Science website explaining how salt works to enhance flavors. News article which summarizes how salt enhances flavors. Explanation of how small amounts of salt enhances sweet flavors. Review of a research article which explains the role of salt in enhancing sweet flavors. Research that explains how salt enhances other flavors by suppressing bitterness. Research which discusses how lowering sodium content of foods for people on low sodium diet also changes other flavors as well. It's like you aren't even trying to provide references. This took me 10 minutes. This is the reference desk, you know, not the "Let's just report my own personal experiences as though they were universal" desk. --Jayron32 20:31, 24 June 2015 (UTC)

Well said Jayron. Richard Avery (talk) 20:43, 24 June 2015 (UTC)

If it only took you 10 minutes, then you apparently didn't read those sources through before recommending them to us. StuRat (talk) 00:42, 25 June 2015 (UTC)

Like -- To sum up -- Yes salt enhances perception of some other flavors in humans. This fact is not currently mentioned in our article that I can see, perhaps someone would be interested in adding a sentence or so, citing one of Jayron's many good sources. SemanticMantis (talk) 21:01, 24 June 2015 (UTC)

That might be premature. The 2nd source Jayron listed says "virtually all published psychophysical studies show that NaCl either suppresses or has no effect on other flavours". (It's behind a paywall, so I couldn't read much further.) StuRat (talk) 21:09, 24 June 2015 (UTC)

said " can't see why, from an evolutionary POV, that would have developed". humans need it to survive! Agent of the nine (talk) 21:11, 24 June 2015 (UTC)

Yes, and that explains why we like salt, but not why we would like foods that are both bitter and salty. Bitter foods are disliked because they may contain substances harmful to us, so why would we no longer want to avoid such foods, just because they are also salty ? (Perhaps if suffering from a sodium deficiency, then the need for sodium might outweigh the need to avoid those bitter compounds ?) StuRat (talk) 21:48, 24 June 2015 (UTC)

It does say that. It then continues

“ To reconcile this [apparent] contradiction we have proposed that salts selectively filter flavours, such that unpleasant tastes (such as bitterness) are more suppressed than palatable ones (such as sweetness) thereby increasing the salience and/or intensity of the latter. We now present evidence to support this idea. ”

emphasis and a word added by me. The title of the paper is "Salt enhances flavour by suppressing bitterness", and that is their primary conclusion. When A and B are both suppressed, but B moreso than A, the result is the perceived enhancement of flavor A. I'm fairly skeptical but I tend to mostly trust papers published in Nature. If you (or anyone else) would like a copy of the whole article, contact me by email through my talk page. SemanticMantis (talk) 21:27, 24 June 2015 (UTC)

Does it list the mechanism by which salt suppresses bitter tastes ? StuRat (talk) 21:44, 24 June 2015 (UTC)

No. This paper [1] by the same authors from 1995 says they didn't know at that time why NaCl suppresses bitter taste, only that they have ample evidence that it does. The same work also implicates the sodium ion is the active part, and that the lithium ion has similar bitter suppressing properties. I would suppose that in the intervening 20 years someone has worked on figuring out the suppression mechanism but that also means figuring out how bitterness itself works. This paper discusses the challenges of understanding bitterness [2], and this one [3] suggests that cGMP might be part of a then-unknown signaling mechanism for bitterness. It might be that nobody yet fully understands the full mechanism by which NaCl suppresses bitter taste, but it also may be that I just couldn't find it in 5 minutes of searching. SemanticMantis (talk) 23:09, 24 June 2015 (UTC)

Something else that was mentioned in the previous Ref Desk discussion is that whether adding salt "enhances other flavors" may vary by individual. I don't believe anyone found any research on the question, however. StuRat (talk) 21:57, 24 June 2015 (UTC)

A comment Alton Brown makes in the Good Eats episode "Eat This Rock" is that "Salt makes food taste more like itself" and "four out of five scientists agree that this is due to salt's ability to electrically turn the volume up on our taste buds." — Preceding unsigned comment added by Tdjewell (talk • contribs) 12:30, 25 June 2015 (UTC)

I mentioned Chinese and French cooks' attitudes towards salt. You mentioned another cook. Everyone else appears to be stuck on arguing about science experiments. I believe that the best answer we can give is that some cooks believe that salt brings out other (non-salty) flavors in food. Scientists don't necessarily agree. 199.15.144.250 (talk) 14:18, 25 June 2015 (UTC)

Well this is the science desk. I agree that information from cooks and chefs is valuable and interesting, but if that were all the OP was interested in, perhaps the Humanities desk would have been a more appropriate venue. SemanticMantis (talk) 14:58, 25 June 2015 (UTC)

In fairness to Alton Brown, his first show (Good Eats) has a very strong emphasis on the scientific explanations behind culinary decisions, even though it is primarily a food entertainment program. Nimur (talk) 16:58, 25 June 2015 (UTC)

Agreed, especially considering the inherent conflict of interest there, that chefs want their recipes to sound impressive so they can charge more and "I know how to bring out the flavor" is likely to sell far better than "I know how to make it salty". The scientists, hopefully, will lack any conflict of interest. StuRat (talk) 15:36, 25 June 2015 (UTC)

The brain has to interpret the signals it gets from its senses and it is well known that the brain uses input from all its senses, even using information that we would think is irrelevant. E.g. Utensil Color, Shape, Size Affect Food Flavor, therefore there is a priori no reason to believe that salt cannot create some effect that looks inconsistent with the effect it should have on taste based only on its saltiness. Count Iblis (talk) 18:14, 25 June 2015 (UTC)

The expression "bring out the flavor" is often used about umami as well as saltiness. There are some traditional ingredients (soy sauce, dashi) and some less traditional ones (hydrolyzed vegetable protein, MSG) that add umami. Foods that are high in umami taste good because they provide the body with protein, in the same way that salty foods taste good because they provide salt and sweet foods provide sugar.

Still, I think cooks say "bring out the flavor" instead of "make it salty" partly because cooking is an art, not a science. Sometimes a cook will know that the ingredient will make the dish hotter, sweeter, or some other specific. But sometimes they just know that adding an ingredient makes the dish taste better. They don't know why, they don't necessarily care why, and there may not even be a "why". Roches (talk) 21:59, 26 June 2015 (UTC)