Wikipedia:Reference desk/Archives/Science/2018 June 8

= June 8 =

Mold or fungi?
Hi. I have a food case that I haven't opened for several months, and it seems that the food case had grown something. Can someone tell me, is it a mold or a fungi, and what type is it? I want to use it to illustrate about mold, but I am quite unsure.--Jeromi Mikhael (talk) 14:13, 8 June 2018 (UTC)
 * Mold are fungi, in case you are not aware. --OuroborosCobra (talk) 14:58, 8 June 2018 (UTC)
 * (ec) Have you read mold and fungus (fungi is the plural)? That definitely looks like mold in your picture (although I'm no expert).  You can see the hyphae on the lump in the top right.  Rojomoke (talk) 15:05, 8 June 2018 (UTC)
 * Can you help me use the picture in mold or fungus article?--Jeromi Mikhael (talk) 04:23, 9 June 2018 (UTC)


 * Sorry but in my opinion this picture is not suitable as an illustration for anything. An illustration should give an idea of the intended item, but I would never have recognise any mold in your photo without you telling us: my first impression of the picture was of an aerial view of a bay with the moon reflecting in blue waters and in the background some dark islands in front of a rocky coast. And I would not recognise any actual molds on the basis of it, I think 194.174.76.21 (talk) 11:10, 11 June 2018 (UTC) Marco Pagliero Berlin
 * Unhelpful? Not attempting? Polyamorph, this is your opinion. But Jeromy's query about molds was also more importantly about whether someone can help him use this picture in some WP-article. That I don't find this picture suitable for any article _is_ answering the query. And nothing is "unuseful" just because it is not exactly the answer someone was hoping to hear. 194.174.76.21 (talk) 16:00, 12 June 2018 (UTC) Marco Pagliero Berlin
 * OK, I'm sorry, I think I made a mistake collapsing your comment as I thought you were responding to the OP as opposed to their second question. Apologies and restored. Polyamorph (talk) 19:34, 12 June 2018 (UTC)

"Cell" cooling towers
Hi experts,

I would like to know whether "cell" type coolers at industrial or power plants are always induced draft cooling towers?

--DCKH (talk) 14:49, 8 June 2018 (UTC)
 * The last one looks like a Crossflow cooling tower: . See also Induced draft vs. forced draft at that link. —2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk) 15:43, 8 June 2018 (UTC) ... Btw, they call them "modular" cooling towers.


 * If they're in small cells like that (1,2,4) they're nearly always fan-blown, not induced draught. Andy Dingley (talk) 15:58, 8 June 2018 (UTC)


 * Most smaller units have a passive mode that is purely water flow, and then the fan kicks on at some point as water flow increases. Small units always have a fan, you need a large tower to induce enough draft to dispense with the fan entirely.  Acroterion   (talk)   01:31, 9 June 2018 (UTC)

Crookes radiometer
Hi, I'm confused by this claim: "Finally, if light pressure were the motive force, the radiometer would spin in the opposite direction, as the photons on the shiny side being reflected would deposit more momentum than on the black side where the photons are absorbed."

On my own, I'd think the other way: (1) the black side gets 100% of photon momentum, (2) while the shiny side only gets a fraction thereof, (3) so there is more push on the black side, (4) so the mill should spin shiny-side forward.

What's wrong? And couldn't the article be a little more explicit about that claim? 82.227.203.82 (talk) 16:08, 8 June 2018 (UTC)
 * Here's a video of a radiometer in action. It's pretty clear, especially at the very beginning, that the black side of each "leaf" is the side being pushed by the sunlight. ←Baseball Bugs What's up, Doc? carrots→ 16:21, 8 June 2018 (UTC)
 * The white side is pulled by angels. - Nunh-huh 16:30, 8 June 2018 (UTC)


 * (2), and hence (3) and (4), is incorrect. The black side gets 100% of photon momentum when it absorbs one, but the shiny face gets not a tiny fraction but 200% (assuming the photon comes and goes perpendicularly to the surface - you can do the funky math assuming non-perpendicular reflexion but the idea is that whatever the result is, it is twice as much as the black side result). Momentum is a vector quantity, and the photon leaves with opposite speed hence momentum (again in the perpendicular case), so the difference in momentum between photon-before and photon-after is larger in the reflection than in the absorption case. Tigraan Click here to contact me 16:43, 8 June 2018 (UTC)
 * Conceptually for such a radiometer in a vacuum, the white side absorbs the photon and then emits a photon in the reverse direction. It gains momentum in the forward direction for both. The black side absorbs a photon and then emits a lower-frequency photons with the same total energy in random directions, so the total forward momentum gain is lower. -Arch dude (talk) 18:30, 8 June 2018 (UTC)

That makes sense, thanks! I like Arch dude's two-step version better, but Tigraan's 200% vs. 100% point is good reinforcement. 82.227.203.82 (talk) 18:40, 10 June 2018 (UTC)

How is estradiol synthesized through Marker degradation?
The sources I've found all seem to think it's "trivial" and are overly focused on male steroids (as expected of articles predominantly written by male scientists), but what is the major exact route to estradiol from diosgenin?? Why can't I seem to find this anywhere? (I have a biochemistry degree, so the devil is in the details!) Yanping Nora Soong (talk) 19:54, 8 June 2018 (UTC)
 * Testosterone→estradiol was Carl Djerassi's graduate thesis. Oxidative aromatization of an enone really is trivial in a conceptual chemical sense, even if the exact details were thesis-worthy especially with what chemistry was known at that time. Careful to avoid letting your own emotion create biases on behalf of others, but instead (as a scientist) do a dispassionate literature search. You may find it is indeed a trivial reaction--this route to the "first" hormone was possibly the difficult/lynchpin stage that allowed diverse derivatives. Oxidative cleavage of the acyl on the D-ring to get the C-17 hydroxyl of testosterone looks more difficult than oxidizing the A-ring. DMacks (talk) 22:00, 8 June 2018 (UTC)


 * How is the methyl group on the A ring eliminated? It's not through any mechanism I know. Yanping Nora Soong (talk) 12:15, 11 June 2018 (UTC)
 * Pyrolysis was the original method (10.1021/ja01148a035). I don't know the mechanism--it's not quite a normal dienone phenol rearrangement because as you note the methyl is lost altogether rather than simply migrating. Obviously 600 °C is not how it happens biosynthetically:) Not sure if the eventual industrial method is related to that (the dienone phenol rearrangement can be acid-catalyzed at moderate temperatures), or if there is something slightly later known in the journal/patent-literature. DMacks (talk) 20:42, 11 June 2018 (UTC)
 * FWIW, biosynthetically the method is aromatase. Amusingly enough, our article shows the biological solution to the problem is to oxidize that methyl all the way to a carboxyl group, then decarboxylate!  Note that the body doesn't typically synthesize estrogen at one go -- women, like men, have hormone-producing cells in their gonads (thecal cells) which produce androgens; but these then enter the ovarian follicle and are changed by follicular cells using aromatase.  The vaguely analogous nurse cells in the testis simply produce an androgen-binding protein that keeps the local level high. Wnt (talk) 14:26, 13 June 2018 (UTC)

Genetic speech impediment
Speech impediment and related articles mention plenty of causes for impediments, but they're all either psychological, or the result of developmental problems, or the results of injuries. Are there any documented examples of genetic impediments? Counterexample — many second-language learners don't pick up unique sounds, e.g. the typical idea of a German or Frenchman who can't get ð and þ (cf. the German Coast Guard video), or apparently most Westerners can't pick up the 'ayin of Semitic languages, but the German's children raised in an anglophone environment and the Western kids raised with Arabs will pick up those sounds quite fine, so it's not genetic. I'm imagining a sound that requires a certain mouth or vocal-cord movement that some populations' genetics don't enable them to perform. In such a situation, a kid from population A, raised from infancy in an exclusively B-speaking context, would still be unable to pronounce a certain sound. Nyttend (talk) 23:12, 8 June 2018 (UTC)
 * See this. Ruslik_ Zero 05:00, 9 June 2018 (UTC)


 * Well, the first thing to do in answering your question is to point out that you have conflated a few different discrete phenomena here. There is a big difference between the role genetics play in normal language acquisition between populations of healthy and neurotypical persons and genetics as they impact upon speech disorders.  So those two topics must be disentangled before anything meaningful can be said in response to your inquiry.  That said, the state of research in both areas is substantial, so it's easy to provide concrete elucidation on both points.


 * As to the notion of populations who have a physiological inability to acquire the phonological repertoire used by some other population (whether by defect in the vocal tract, places of articulation, or the neurological structures which impart language facility), the answer is no: no such phenomena has ever been observed anywhere in the world. The normal rules regarding language acquisition which you allude to (environmental feedback in early development causing a person to gain facility with distinguishing and pronouncing certain phonemes, generally to the exclusion of others, as per the needs of their first language or languages) are pretty much universal to all neurologically healthy human beings.  This is not to say that there is zero variance between individuals with regard to how long into development the brain stays plastic and how readily said individual may pick up the ability to distinguish phonemes in a new language.  But as regards regular language acquisition, there is no such thing as a population that is genetically incapable of pronouncing a certain sound which other populations regularly use; both the physiology of the voice box and the fitness of the language organ are more or less uniform across our species.  Some relevant articles here are first language acquisition, phonology, and articulatory phonetics.


 * Are there however familial lines of heredity in which defects to the normal use of language (such as your example of a speech impediment) can be carried by virtue of herditary mutation? Yeah, of course. It's not common, because such severe difficulties with language production are (relatively speaking) quite rare, and usually they are (as you noted) caused by developmental issues, which means they are better understood as an issue of epigenetics than straight-forward lineal genetics.  But there certainly are cases where language deficiency can be passed from parent to offspring.  It's more likely to be a purely neurological issue, a disorder of neuromotor or muscular function in the maxillofacial region, or a deformity of the structure of the nasal or oral cavities, though; malformations of the voice box are not a common deformity, and a variety which affects only that portion of the airway and no other is rarer still.  There are also uncommon motor disfunctions which affect the voice box, but here too, defect in ability with an articulator is more common. Snow let's rap 06:57, 9 June 2018 (UTC)


 * Excellent answer. A quick example of a genetic condition affecting the ability to speak and form normal sounds: Down syndrome. As this paper points out, however, it's not 100% clear how much is genetic (versus epigenetic or other). Matt Deres (talk) 14:23, 10 June 2018 (UTC)

I'm sorry, but I apparently chose the wrong terms; this isn't at all what I was asking about. Imagine that tongue rolling is genetic, as until recently I'd always understood it to be. Next, imagine that population A is 100% capable of tongue rolling, and their language includes sounds that require it. Meanwhile, an unrelated population B is 100% incapable of tongue rolling. This isn't considered a speech impediment among them, or among those with whom they're in contact, because tongue-rolling-influenced sounds aren't parts of any of their languages. However, were B people placed into population A (even if placed as pre-vocal infants), they'd never be able to speak A fluently, and they'd be considered to have a speech impediment, because they'd be physically incapable of producing one of its sounds. My question Has this kind of situation ever been documented? Nyttend (talk) 21:20, 10 June 2018 (UTC)
 * Are you referring to the ability to trill? ←Baseball Bugs What's up, Doc? carrots→ 21:43, 10 June 2018 (UTC)
 * That article doesn't say anything about physiological (in)ability, so apparently not. Nyttend (talk) 21:51, 10 June 2018 (UTC)


 * No, as I said in my answer above (though perhaps I was not as clear as I thought), this scenario does not happen and has never been observed in the history of modern scientific inquiry into human language and physiology. All populations of human beings are constituted almost entirely of persons who, if raised in the right environment with the right exposure, would have zero difficulty enunciating the full stock of phones of the local language.  Again, there are many conditions which cause individuals to have difficulty with language production, but in the rare case where these conditions are genetic, they are particular to specific lineages, not the broader population.  I'll rephrase one more way to be clear: for any population of people (beyond the family unit) anywhere on planet Earth, if you took the average and healthy individual from that population as a baby, you could put them into any other population anywhere in the world, speaking any known human language, and they would grow up speaking that language without difficulty of pronunciation.  There are many conditions which can cause individuals to have general difficulty with language production, and some of them hereditary and thus may be common to a small kin group, but there is no such thing as a "population speech impediment", such that an entire population would be physiologically incapable of exercising a particular place of articulation.  The physiology of all speech organs is more or less identical between all populations of humans. Sno</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 03:37, 11 June 2018 (UTC)


 * Incidentally, Nyttend, you may find this fascinating given your general interest here: every language is pretty much comprised of human beings that use the vast majority of all possible phones; it's just that only a subset of the distinctions between these sounds are phonemic in a given language. So, for example, I'm sure you know that in Chinese [mā], [má], [mǎ], and [mà] (ponounced here) are four different words, differing only by tone, whereas in English, there is merely one word (albeit with different homophonous meanings): [ma], colloquial for "mother" and/or a pronunciation of "my" in certain dialects.  But it's not that we don't say [mā], [má], [mǎ], and [mà]; we simply don't distinguish between them phonemically.  So suppose you are Jed Clampett responding to "Ma" Clampett telling him what to do:  "Ah, maaaaa!" (probably pronounced [má]) or "Yes ma." (probably pronounced either [mà] or [mā]).  You use the sounds, but they are not phonemic to you as the two pronunciations have the same exact received meaning (other than perhaps an emotional subtext).  It's the same with most other sounds that human beings regularly make for the purposes of conveying meaning with their voice box and speech organs; most of them get used in every language, but go relatively unnoticed and uncommented upon.


 * Returning to the original topic, one of the reasons I am taking care to be super explicit here is that there is a racist history that underlays the topics to which your question is reaching (though needless to say, I recognize your interest is a purely empirical one). There was a time when white colonialists (quite predictably) assumed that language ability was not uniform and that there were significant differences in the basic mechanics and complexity of the languages of white races, and those of others (including folk theories about the differences in the anatomy of the speech production, such as you are inquiring about).  But it just turned out not to be the case, at all.  And thankfully, experts began to recognize this quickly, because linguistics as a field started to gain its empirical rigor early in the era of modern science, in part because of the brilliance of some of it's foundational figures, who often (though certainly not always) resisted the kind of rampant racial bias that was common in that era to other burgeoning sciences regarding the human mind, body, and faculties thereof.


 * And one last little sidenote: it's worth mentioning that even with conventional, individual speech impediments, the difficulty is generally caused by neurological irregularity, rather than a deformity with an articulator. Hope some of this is of assistance or interesting! <b style="color: #19a0fd;">S</b><b style="color: #66c0fd">n</b><b style="color: #99d5fe;">o</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 04:56, 11 June 2018 (UTC)
 * Thank you for the detailed responses. Part of my problem is that I didn't understand a bunch of what you said the first time around, and since it was followed up with a reference to Down syndrome, I figured you'd gone that direction, talking about individuals with inheritable speech impediments rather than entire populations who were unable to pronounce something or another.  Re your every language is pretty much comprised: no I didn't know that.  Interesting.  I just know that there are a decent number of vowels and several consonants found in Western European languages but not in English (consider that's uber cool versus über alles in der Welt, or el perro, which I can pronounce only as el pero), and I know that there are tons of unrelated language families and that some have totally unrelated sounds (e.g. 'ayin, or click consonants), so I figured there might be a wide range of sounds entirely absent from English and all other languages about which I know anything.  Nyttend (talk) 00:10, 12 June 2018 (UTC)
 * Yes, to be fair, there are some outlier phones which are not generally used in most languages, even non-phonemically--and click consonants are a great example; used prominently in the Khoisan languages, but very rare outside that superfamily, even as an incidental articulation. But the important take-away is that whenever sounds are non-phonemic in a language (or even phonetically absent altogether) it is the consequence of the fact that the native speakers do not have a pressure to acquire that sound or phonemic distinction within the critical period of language acquisition--such that even if they do hear it as adults (in the acoustic/phonetic sense) they may not be able to as fully perceive/distinguish it as they might have had they developed in a different linguistic environment; the same goes for production/pronunciation. <b style="color: #19a0fd;">S</b><b style="color: #66c0fd">n</b><b style="color: #99d5fe;">o</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 07:40, 12 June 2018 (UTC)


 * I'm not going to take the time to look now, but the way I'd address this would be to search speech on OMIM.  And just sort through all the stuff that comes out. Wnt (talk) 22:16, 11 June 2018 (UTC)


 * Well that's a great resource, but utterly useless to the present inquiry, as a) the data there is not cross-referenced to populations, which is what Nyttend was inquiring about, b) persons with those disorders (let alone a given disorder) would make up only a very small subset of the populations in question in any event and c) even if a and b were not the case, you'd need to be a trained geneticist with considerable time and resources to crunch the data to come up with any meaningful associations. A review of the discussion above might make it more clear why just having access to a list of genetic conditions which complicate language production does not really open the door any kind of meaningful conclusions regarding Nyttend's question. <b style="color: #19a0fd;">S</b><b style="color: #66c0fd">n</b><b style="color: #99d5fe;">o</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 07:50, 12 June 2018 (UTC)
 * I stand by my comment. If some genetic factor controls the ability to make speech, then there will be noticeable variation in any population, which is to say, some people will have trouble speaking their own native tongue.  Those people will have sought treatment, their relatives will have been mentioned, and eventually, some description of the syndrome should have entered the literature, if not as a mapped locus, at least as a condition with a known hereditary component. Wnt (talk) 14:13, 13 June 2018 (UTC)
 * None of which has even remote impact upon Nyttend's question or validates your proposed strategy for answering that question. Nyttend was pretty clearly inquiring about whether there are entire language group populations who are incapable of pronouncing certain phones or who have unique physiological traits to their articulaors which allow that population to pronounce sounds that the people of other populations cannot, a question which can be easily answered in the negative with reference to accepted science in the field.  The question was not "are there populations of people in which there exist genetic conditions that cause some people to have difficulty with languages?" a question that would also have a rather uncontroversial and obvious answer: "Yes, of course."  Look, I don't want to be incivil here, but there is just no way that you can backstop your "The way I would address this is to..." comment in such a way that it makes any kind of sense; you're suggestion is fundamentally flawed to the point of being gobbledygook, no matter how firmly you stand by it.  It was an out-of-one's-depth, drive by answer by someone who didn't understand the question or the basics of how to address it, and which could only serve to foster confusion about the actual answer; i.e. the type of thing we've been trying to discourage here recently. <b style="color: #19a0fd;">S</b><b style="color: #66c0fd">n</b><b style="color: #99d5fe;">o</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 04:22, 14 June 2018 (UTC)
 * Entire populations of humans all of whom have the same trait without exceptions? Not unless they're in that Nazi space base on the far side of the Moon...  I mean seriously, even among native Africans there are enough white individuals born to keep the muti doctors in clover.  As far as I can tell we're in agreement on that point, which makes the apparent argumentativeness of your response perplexing.  The obvious next step to me is to see whether languages could be shaped by local frequencies of impediments, i.e. whether the percentage of people who can't trill their Rs for genetic reasons is what determines whether a language has a trilled R.  And for that you need more data.  I wouldn't think it would take a very large percentage of impediments to change a language, since the non-impeded would be expected to have little opinion about the matter, but I don't know that. Wnt (talk) 22:08, 15 June 2018 (UTC)


 * You've completely turned logic on it's head there, and for the purposes of trying to argue against 'extremely rudimentary consensus science in the relevant fields (again, without even seeming to really understand the question being asked and how it can be answered). Nobody said, implied or even went near the idea that all people in a given population will have the exact same physiology with regard to speech production, and trying to link that (half-formed) thought to Nazi eugenics to try to bring some vitality to your uninformed response is beyond the pall.  The fact that you are trying to say that some groups of people lack certain basic underlying capacities for language is the actual view that comes from actual historic racism; a view that was completely rejected and discredited by researchers nearly a century ago, and re-confirmed by every relevant finding of linguistics, genetics, and speech physiology ever since...


 * And, in fact, if you had taken the time to review the actual answer to the OP's inquiry above, you'd see that all of this was discussed and that a part of that answer completely depends upon the assumption of variation between individuals; no population beyond a very small kin group, completely ( or even remotely predominately ) lacks the ability to produce a given sound, and that is what you would need to be able to say in order to answer Nyttend's question in the affirmative. So I guess I have to repeat this again: A) If you took all of the conditions listed in the OMIM and spent the time necessary to isolate all of those for which speech production is implicated, the people who suffer from them would only be a fraction of all people in a given language group population.  B) Even if we ignored that basic reality (which is insane), the OMIM would be wholly insufficient on its own to shed any light on the matter in the way you suggested, because it doesn't contain population genetics data of any sort useful to such an inquiry, so now we're in double your-statement-was-complete-nonsense territory.  I don't know how many different ways I can repeat this information, but the fact of the matter is that your suggestion doesn't make sense and never will, no matter how many times we repeat this cycle.


 * And even if we warp ourselves to an alternate dimension where your assertions did make sense, suggesting that someone "could answer the question" by deconstructing the millions of pages of complicated data that the OMIM would then have in its databse would never be a sensible way to answer an inquiry here, by even the most remote stretch of the imagination--especially when we can instead look to the basic conclusions of actual scientists in this field, as opposed to random speculation by forum dilettantes. And there the answer is again well established: all races of people, regardless of the realized form of their language's phonetics and phonemics, have a universal stock of phones which almost all individuals are genetically capable of producing, if raised in the right linguistic environment.  And any assertion from a previous and more bigoted era that the contrary may be true is a notion that has been dead nearly as long as modern linguistics and physiology have been around.  <b style="color: #19a0fd;">S</b><b style="color: #66c0fd">n</b><b style="color: #99d5fe;">o</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 02:27, 16 June 2018 (UTC)


 * FYI, I don't like having to be this strident and I don't do it lightly, but your claims have the potential to substantially misinform here, and they imply an idea that has been traditionally asserted to try to make the claim that humanity is made up of different "sub-species", and I feel strongly that we cannot have a situation here where random speculation gives even illusory support to such ideas. So I felt my hands were tied in making it as plain as possible that what you were saying does not match with reality and rests on ideas that have been debunked for a long time--even if that meant calling a fellow editor out.  <b style="color: #19a0fd;">S</b><b style="color: #66c0fd">n</b><b style="color: #99d5fe;">o</b><b style="color: #b2dffe;">w</b> <b style="color: #d4143a">let's rap</b> 02:43, 16 June 2018 (UTC)