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July 28

Hearing: difference in sensitivity to harmonics and intermodulation.

The reproduction of sound through electronic devices inherently involves "non-linear distortion". It has been known for a very long time that distortion occurs in two forms: harmonic (extra tones in harmonic relationship to source fundamentals) and intermodulation (non-harmonic extra tones that are the sum or subtraction of source tones), and that the ear is both more sensitive to, and finds it more objectionable, to the intermodulation form. For example, the motion picture industry devised a specification and test (the SMPTE test) for maximum allowable intermodulation almost as soon as sound movies were devised. Harmonic distortion they weren't much concerned about.

It seems that this extra sensitivity to intermod is inherent in the structure of the inner ear. Almost all natural sounds contain lots of harmonics. Intermod pretty much does not occur in nature. Does anyone know what evolutionary advantage this has conferred, remembering that human evolution is essentially stopped at the caveman era, or perhaps at the stone age era, when there was certainly no high quality electronic sound? Or is it that excess sensitivity to intermod conferred no evolutionary disadvantage? One would think that as harmonics are normal in nature, that that is what we ought to be most sensitive to. 118.209.51.33 (talk) 16:37, 28 July 2018 (UTC)[reply]

Evolution hasn’t stopped. There was not a ‘direction of travel’ of evolution to arrive at where we are now, for humans, giraffes, hippopotami, or dinosaurs etc. — Preceding unsigned comment added by 82.38.221.49 (talk) 17:30, 28 July 2018 (UTC)[reply]

So? How does that help?118.209.58.85 (talk) 16:24, 29 July 2018 (UTC)[reply]

Human hearing ability has ceased to be a parameter for evolutionary selection since our hominid ancestors struggled in a predatory environment. Our hearing sensitivity and frequency range have become inferior to the cats and dogs around us, though we claim to have developed a finer tuned cultural appreciation of sound (music) than they. We also value our hearing directionality, a hangover from the use of hearing in stealthy stalking or predator avoidance, enough to invest in Stereophonic sound reproducers. This direction sensitivity depends on relative signal phases at each ear (compare with Phased array ultrasonics). A reason intermodulation tones are objectionable is that they can only confuse detection of a sound's direction while harmonic distortion of a single tone does not impede hearing where it originates. DroneB (talk) 13:20, 30 July 2018 (UTC)[reply]

No. While GROSS intermodulation distortion (several percent of total sound energy) can make perception of direction difficult, the ear can detect intermodulation at far lower levels, and find these levels unpleasant. Electronic engineers has found it necessary to get intermod in sound equipment below 0.1%. OP121.44.191.221 (talk) 02:35, 31 July 2018 (UTC)[reply]

In case it's still not clear to the OP, when your conclusion is based on a faulty premise, it could easily be flawed. The idea that human evolution basically stopped at the stone age or the caveman era is not generally accepted as true. (It's true that some evolutionary biologists have made that argument but I wouldn't say it's widely supported [1] and even for those who have made it, I don't think they intended it to be taken the way some e.g. in the paleo movement have done. And obvious reason is it's easy to find examples which show it's untrue e.g. lactose persistence or the various genetic resistance to malaria.) To be fair, I'm not sure if this particular premise matters so much. If you're right that intermodulation distortion basically only really occurs with electronic (or even electric) sound, and not with other forms of human induced sounds, I think few would suggest there has been sufficient evolutionary pressure to result in such a significant shift in how we hear it that it's something that is widely untolerable. However the wider point remains that if you are coming to a conclusion, you need to be sure your premises are correct and lead to those conclusions. Nil Einne (talk) 19:55, 30 July 2018 (UTC)[reply]

Evolution in humans has essentially stopped. That is something that is abundantly clear. It is true that some think it hasn't but then some people believe the Earth is flat, and some don't believe in evolution at all, and have got laws in some US states to ban teaching it. And if you think humans have evolved to enjoy electronically reproduced sound (pretty much the only source of intermodulation), then you must be on a substance. But in any case, all this has actually little to do with my question. OP121.44.191.221 (talk) 02:35, 31 July 2018 (UTC)[reply]

No credible astronomer or physicist believes the earth is flat. Probably most evolutionary biologists do not accept human evolution stopped in the stone age or cave age, as per my ref. There is a big difference. As for your second point, it has nothing to do with what I actually said since I specifically noted that if intermodulation truly arose with electronic or electric sound, it is unlikely anyone would credibly suggest there was sufficient selective pressure to cause it to have arisen. As for your third point, I already explained why it has to do with your question. If you are unwilling to accept you may be wrong, or think being wrong makes you an idiot, that's your choice, but it means you are unlikely to be able to get any help on the RD. Nil Einne (talk) 05:09, 31 July 2018 (UTC)[reply]

If I understand this question, the OP is asking whether the aesthetic appreciation for sound is derived from an evolutionary tendency - and in specific, if there is an evolutionary reason to prefer certain harmonic tones, as opposed to non-harmonic combinations.

The answer should be a clear and sonorous no, this aesthetic preference is not an evolutionary effect; this is a learned, acculturated phenomenon related to the history and culture that has had a dominant effect on the music and sounds that many of our readers are exposed to.

Our article on Tonality is a good starting place; and our ancillary article, Atonality, has this to say: "the term atonality describes music that does not conform to the system of tonal hierarchies that characterized classical European music between the seventeenth and nineteenth centuries..." (with just massive amounts of citations to great music-theory sources all throughout that article).

So: no, we humans did not have any evolutionary or biological reason to prefer harmonic sounds, nor was there any evolutionary reason to dislike nonharmonic sounds (including, but not limited, to the sounds caused specifically by intermodulation of acoustic frequencies). Any such predisposition that you or others may have is a learned behavior that is heavily influenced by your exposure to the musical traditions of renaissance-era Western European societies, and the more subsequent modern music that developed from those cultures.

Nimur (talk) 05:13, 30 July 2018 (UTC)[reply]

These are very definitive statements, but I'm not convinced that they are correct. Harmony actually has a very strong and straightforward physical significance. When you have a simple source of sound, it usually produces a base frequency and a set of "harmonics", that is, tones with frequencies that are integer multiples of the base frequency. As the name indicates, the harmonics harmonize with each other. When you have multiple sound sources, the tones that they produce typically do not harmonize with each other. Therefore, harmony is a signal that a sound comes from a single source. Thus, the ability to perceive harmony goes with the ability to distinguish single sound sources from multiple sound sources. I can't prove that that has evolutionary importance, but it does seem plausible to me. Looie496 (talk) 14:44, 30 July 2018 (UTC)[reply]

It sounds like the OP is saying we shouldn't really hear or care about intermodulation distortion much because it rarely occurs in nature so it's not something the ear should have evolved sensitivity to. They are therefore wondering if the structure of the inner ear evolved in such a way to cause sensitivity to intermodulation distortion and why it would have done so. Or if alternatively because intermodulation did not occur, there was no reason for us to evolve to have little sensitivity to it but there was for harmonic distortion. Personally I think the OP's question is based on too many faulty assumptions and misunderstandings, but I'm not sure if Nimur's answer really properly addresses them. Nil Einne (talk) 19:55, 30 July 2018 (UTC)[reply]

I don't know enough and haven't put in the time to riddle this out, but there is a lot about harmonics in the cochlea, e.g. [2] I would speculate that there may be a difference in how much the two types of distortion affects the final neural signal, but I don't know that. Wnt (talk) 14:36, 30 July 2018 (UTC)[reply]

The unpleasantness of IM (intermodulation distortion) is the reason loudspeakers for music are constructed with multiple transducers in the same enclosure, each reproducing only a part of the audible frequency range. Is it feasible, either theoretically or on practice, to remove IM from an old recording by modelling and inverting the signal non-linearity? DroneB (talk) 00:24, 31 July 2018 (UTC)[reply]

This is off topic, but you are correct about loudspeakers. It is theoretically possible to remove intermod from old recordings to some extent, but in practice its extremely difficult and usually impossible. There are essentially three reasons why it is extremely difficult:-

Many musical instruments have a tonal structure that is not precisely harmonically related. Snare drums have a large number of frequencies in their sound, but they are NOT harmonically related. Pianos are tuned so that the string relationship is close to harmony, but not exact. Some pianos (eg honky-tonk) are quite well off harmony. The human voice contains overtones that are not harmonically related.

I was once engaged in the design and manufacture of guitar amplifiers. It's one thing you learn in that business, it's that if there is some effect or artifact, some musician somewhere will devise a way to exploit it in a hit tune. For example, fuzz, widely used in rock and to some extent in jazz, is gross distortion. How does some machine identify what's unwanted distortion, and what's not?

The number of additional tones created by intermod rapidly becomes very large as the number of tones in the source sound increases. You would need a warehouse full of supercomputers to figure it out, for any but the acoustically simplest of recordings.

Note that an overtone structure, such as the human voice or a piano, or percussion instruments, is NOT imtermodulation, and doesn't sound like it, but its still additional tones just as intermod is, so is diffult to distinguish mathematically. OP 121.44.191.221 (talk) 03:00, 31 July 2018 (UTC)[reply]

I appreciate the time and effort by everyone who responded (except Nil Einne, who works on the basis of "I don't know how to answer this, so lets just say the OP is an idiot". Just what misconceptions have I displayed??), but you are all off track. I'll try and clarify my question: Human hearing is more sensitive to small amounts of intermodulation distortion (something not experienced by humans until the invention of radio and movie sound tracks) than it is to harmonic distortion (also an artificial thing). This seems to be inherent to the structure of the inner ear. Is there a possible evolutionary reason why we ended up with that structure, noting that sensitivity to intermod has little or no benefit in nature? My question has nothing to do with tonality or appreciation of Western music. As the motion picture industry quickly found out 100 years ago, intermod is objectionable at very low amounts, regardless of whether it's voice, music, or sound effects.

Since intermod almost never occurs in nature, I am assuming that the ear's sensitivity to it is an accidental by-product of a solution that was a response to some evolutionary pressure, which must have been prehistoric and most likely goes back to the appearance of early mammals or even earlier. OP121.44.191.221 (talk) 03:24, 31 July 2018 (UTC)[reply]

Except I never said you were an idiot. I'm not sure why you believe being wrong makes you an idiot, but that's your own problem. It's clear from all my responses that I'm acknowledging that your understanding of audio physics appears to be significantly greater than mine, so it's even less clear why you believe I would call someone an idiot despite their understanding on one area clearly being greatly superior to mine. Both me an the other IP specifically noted your points on evolution are largely incorrect. I provided a ref demonstrating part of this. I also tried to understand what you were asking, and from what I can tell I understood it better that what Nimur did. I attempted to help you by trying to explain what you were asking since I believed, and from your response I believed correctly, that it had been misunderstood and so Nimur's response wasn't really addressing it. In fact your clarification is very close to what I was already thinking, and what I tried to convey with my response to Nimur and Looie496, My mistake for trying to help. Nil Einne (talk) 05:09, 31 July 2018 (UTC)[reply]

Yes, of all the responders, you came closest to understanding what I was asking. You mentioned that I thought that as intermod pretty much does not occur in nature, there cannot have been any direct evolutionary pressure to acquire sensitivity to it. It must have been a by-product of some other pressure. Note that harmonic distortion also is not a natural phenomena - it too is an artifact of electronic sound reproduction. However you stated "the OP's question is based on too many faulty assumptions and misunderstandings." But you did not explain/describe just what those assumptions and misunderstandings were. And you could have just declined to post. So, the inference is clear - you think my question is stupid and does not merit an answer. If you had explained/described what was wrong, that would have helped. Or, to put it more plain - you think I'm an idiot (which might well be the case), but isn't the purpose of this website to help, idiots or whatever?

I wish I had not said evolution in humans had effectively stopped. That actually has no real bearing on the question, except that it is obvious that we cannot have evolved to listen to electronic reproduction, and it has caused people to go off on a tangent (eg the "other IP" you mentioned). The human ear has certainly not changed in that time. In fact its really the old Mark XX Mammalian Pattern Ear, with a good brain attached that can understand advanced speech. OP 121.44.191.221 (talk) 05:32, 31 July 2018 (UTC)[reply]

I will not be responding further for reasons I will outline on ~~the RD~~this latest IP talk page. Nil Einne (talk) 05:36, 31 July 2018 (UTC)[reply]

I was mystified by Nil Einne's mentioning of "IP talk page" until it occurred to me to just click on <talk> after my IP. Click on it and you'll see Nil Einne's got his knickers twisted. Oh well. If someone has a go at answering my question, that's great - I can assure you any genuine help will be appreciated. If not, well, I am unlikely to post any more questions. OP118.209.32.109 (talk) 06:52, 31 July 2018 (UTC)[reply]

Red meat and diabetes

Red meat says A 2016 literature review found that for the each additional 50g per day of processed meat (e.g., bacon, ham, hot dogs, sausages) consumed, the risk increased 4% for total prostate cancer, 8% for cancer mortality, 9% for breast cancer, 18% for colorectal cancer, 19% for pancreatic cancer, 13% for stroke, 24% for cardiovascular mortality and 32% for diabetes. The source is [3] ("Free Access"; not sure if that means it's open access or that I can access it due to my on-campus IP address), and most of its references to diabetes are merely comments; the exceptions are Table 1, Figure 2, and Figure 3. [Figure 3 proposes a mechanism whereby various chemicals in red meat trigger insulin resistance.] Am I missing something, or does the author merely give the statistics (with sources, of course) and propose an explanation, or does he give methodology somewhere? Here in the USA, at least, individuals with higher consumption of red meat have disproportionately high rates of general poor eating, including obvious diabetes-associated sugary foods. If the latter, it's still a reasonable thing to state in a research article because it poses a topic for research ("does red meat cause diabetes, or is it associated with something else that causes it?"), but by stating this information where we do in Red meat, we're implying causation, which isn't seemingly appropriate unless the author's reviewing studies with control groups whose diets were similar minus the red meat. Nyttend (talk) 17:06, 28 July 2018 (UTC)[reply]

These are just correlations that may disappear after appropriate adjustments as already mentioned in the article. Ruslik_Zero 17:40, 28 July 2018 (UTC)[reply]

AFAIK, red meat increases bowel and colon cancer from 4-5% to 5-6%, i.e. if one consumes lots of read meant for most of his/her life. Tgeorgescu (talk) 04:17, 29 July 2018 (UTC)[reply]

A study I assisted, which resulted in a publication titled "A Prospective Study of Red Meat Consumption and Type 2 Diabetes in Middle-Aged and Elderly Women," found that there is a positive correlation between red meat and/or processed meat intake and type 2 diabetes. IT was limited to a population of about 35k women age 45+. The risk was adjusted for multiple know variables. The ending correlation was very small, but significant. The highest correlated subgroup was bacon followed by hot dogs. 209.149.113.5 (talk) 17:19, 30 July 2018 (UTC)[reply]

Link to 209.149.113.5's study. Thank you! Nyttend (talk) 01:23, 31 July 2018 (UTC)[reply]

Type-2 diabetes is caused by eating fat. Count Iblis (talk) 19:32, 30 July 2018 (UTC)[reply]

See Cherry picking and WP:MEDRS. Your source is crap, and as you always do, you enforce your peculiar singular opinions about nutrition on the reference desk by finding sources of questionable reliability that ex post facto conform to your peculiar, otherwise unsupported beliefs. Lifestyle causes of diabetes mellitus type 2 does not make it out so simple, and unlike the shit source you just posted, does itself reference several well-respected peer-reviewed journals. Yes, fat intake is linked partially to type 2 diabetes, but you, and that article, make a definitive, direct causal link that actual reliable sources don't. There is not a one-to-one correspondence, and correlations between fat intake and the disease in question are only one of the melange of possible causes of the disease. Please just stop, and keep it to yourself from now on. Saying nothing at all is more helpful than spewing crap like this.--Jayron 32 02:52, 31 July 2018 (UTC)[reply]

I feel a big issue is use of the word "significant" in correlation studies. It doesn't mean "important" or "extensive." It means "cannot be solely attributed to random factors within the confines of our study." So, if I do a study and I find that there is an extremely weak, but "significant," correlation between fat intake and DM, a non-scientific person might think that I am saying fat intake and diabetes have a significant, e.g. important or extensive, relationship. What I'm really saying is that I haven't been able to completely rule out the correlation as random. Sometimes it turns out to make sense. Beta blocker usage and lip cancer have a significant correlation and, currently, doctors advise beta blocker users to apply SPF lip balm or wide-brim hats. Also, Februrary (regardless of the hemisphere) and raised blood pressure have a significant correlation. Why? There is no known reason because the effect is worldwide. So, you can't blame the cold (it is warm in the Southern Hemisphere in February). You can't blame air pressure or humidity, which is different all around the world. You can't blame diet. That month holds no significant worldwide diet change. It is just than when the Earth is in a certain position relative to the Sun, more than half the humans appear to have slightly raised blood pressure. In this case, significant simply means we haven't found a way to rule it out as random (yet). 209.149.113.5 (talk) 12:54, 31 July 2018 (UTC)[reply]

(ec) @Jayron32: There's no sense getting too carried away, because the Wikipedia article you link makes the same claim as the one Count Iblis linked ... though it is far more restrained in its wording.

To be sure though, there are also relevant foods with a positive role -- cinnamon and cassia, the most commonly used traditional Chinese drugs for the disease, which at the very least are a useful source of dietary fiber for weight loss, and may have other chemicals of note, apples, whose pectin can reduce sugar spikes in the short term, broccoli which contains glucoraphanin. Also coffee has been reported to reduce the risk of the condition -- though oddly, searching now I see this effect attributed to cafestol, which isn't the compound I thought they said before. Wnt (talk) 12:58, 31 July 2018 (UTC)[reply]

The problem doesn't have much to do with the evidence, rather the fact that the general population has a lifestyle that's so extremely unhealthy that the general lifestyle advice is more about damage control than giving advice on what's optimal for a people who are willing to go the extra mile. Let's take a look at this news report. Let's accept the results as "the truth" for argument's sake. So, let's assume that 800 grams of fruits + vegetables is indeed a lot better than 400 grams. Then under that assumption, the official advice would still not change, because, as the asrticle says: "Dr Aune said the findings did not mean the five-a-day message needed to change. He told the BBC: "There are many different considerations if changing policy, it's not just the health effects - is it feasible? " and "Dr Alison Tedstone, chief nutritionist at Public Health England, said: "The five-a-day target is the foundation of a healthy balanced diet and is an achievable way to help prevent a number of diseases.

"Whilst consuming more than five portions of fruit and vegetables a day may be desirable... adding pressure to consume more fruit and vegetables creates an unrealistic expectation.""

So, when Jayron is eating his steak with some potatoes and vegetables floating in fat, he thinks that's not too bad because he is still sticking to the "five-a day message". So, why give that up and eat like Count Iblis? The answer is given here, and here, and in the link I gave above that Jayron dismissed as a crap source. This article is worth reading, it mentions how Alderman dismisses the science on salt intake just like Jayron does here on fat intake. Count Iblis (talk) 17:02, 31 July 2018 (UTC)[reply]

Why are you telling me what I eat? I've never had a meal with you, to my recollection. I've never tried to give advice to people on what to, and not to eat, not the least of which by cherry picking sources. I didn't say you should be giving different advice to people. I've said you shouldn't be giving advice to people. Keep it to yourself, is what I said. --Jayron 32 12:00, 1 August 2018 (UTC)[reply]

I didn't give any advice to people. That eating fat in the quantities most people do is extremely harmful for health is a hard, rigorously proven fact. It's not medical advice to say so, as it doesn't imply any advice on how to eat healthier. Now, the fact that this is controversial within medical science, is because medical science isn't a hard science like physics or chemistry. You cited WP:MEDRS, but this paints a rosy picture about how reliable the most reliable sources in medicine are. In reality a lot of junk gets published in the top medical journals. In a field like physics, Dr. Alderman mentioned in this article and in this one couldn't possibly have gotten away with doing his research in the way he goes about it. It would be considered to be outright scientific fraud, but in medicine this is acceptable. As mentioned in the second article: "As usual, Alderman, a coauthor, has once again failed to declare that he has worked over many years as a consultant to the Salt Institute. As editor-in-chief of the American Journal of Hypertension, this could be viewed as a very serious conflict of interest." Count Iblis (talk) 20:06, 1 August 2018 (UTC)[reply]

Also, we need to note here that the link between lifestyle and T2D is context dependent. What passes for lifestyle factors in diseases in most sources is actually the effect of an even worse lifestyle than sticking to the (not so healthy) norm. E.g. in an absolute sense, the Mediterranean diet would have to be considered to a be a rather unhealthy diet, because the people who stick to such a diet have massively higher rates of heart disease and strokes than the Tsimané people: "Heart attacks and strokes are almost unknown amongst the Tsimané thanks to a high carbohydrate, low protein diet and active lifestyle, say researchers". Count Iblis (talk) 17:30, 31 July 2018 (UTC)[reply]

Tractor model (Montana 1991)

Which model is this tractor? --Nato-Strichmännchen (talk) 19:09, 28 July 2018 (UTC)[reply]

Looks like an older model of the Massey Ferguson 230. It seems definitively from this company.--Doroletho (talk) 12:18, 29 July 2018 (UTC)[reply]

Dissenting opinion: wrong front suspension for a MF, wrong color for a 230, wrong grill, etc. The color, grill and front suspension suggests Minneapolis-Moline to me. Cf: grill here and suspension here. Can't place the model, however. 2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk) 21:04, 31 July 2018 (UTC) . . . Very similar to 1962 MINNEAPOLIS MOLINE GVI[reply]

July 29

Force in rocketry, possibly for quarks inside proton, anywhere else?

Hi if t is time, p(t) is momentum of a pointlike object with mass, then classical physics says that p(t)=m(t)v(t) where m and v are mass and velocity of the opject, and that the net force F(t) is p’(t) = m(t)v’(t) + m’(t)v(t). In a rocket if the mass loss due to fuel consumption can make m’(t) a large enough negative number, can m’(t)v(t) become almost as great in magnitude though of opposite sign, to m(t)v’(t)? Is it possible to gain great increases in speed with small amounts of force this way? My second question is if quarks inside a proton could experience relativistic increases or decreases in mass so rapid that the contribution to net force of m’(t)v(t) is comparable or even much greater than that of mv’(t)? My 3rd question is that since the charges on quarks would complicate even the classical picture (what with electromagnetic radiation), are there noncharged particles that experience th strong force in the same way quarks do, so that a similar regime of m’v dominating could exist in a simpler way? Thank you Rich (talk) 03:38, 29 July 2018 (UTC)[reply]

Well, according to Newton's law F=m*a. So, in order to accelerate a ship of mass m, one needs a force F, there is no way around that except for gravitational slingshots (using planets/moons). If m diminishes, yes, the acceleration would be higher, but there is a limit to it (i.e. when all fuel got burned). With present-day technology it isn't possible to separate the quarks inside of a proton (anyway, not upon a spaceship). Tgeorgescu (talk) 04:13, 29 July 2018 (UTC)[reply]

No, F=ma when m’(t)=0.Rich (talk) 05:37, 29 July 2018 (UTC)[reply]

if one has to look at the the rocket case as a closed constant mass system that includes the exhaust gases, as i just learned a few seconds ago, how does one deal with a case where mass isnt being lost by or gained by something like fuel consumption, but instead by relativistic mass increase?Rich (talk) 05:50, 29 July 2018 (UTC)[reply]

In Newtonian mechanics the change in mass is not part of the force equation. If the mass is changing over time/space that will be included in calculations of impulse and work, but that's it. In the relativistic case, you simply use a corrected force equation, like p = γm₀v, F = dp/dt. Someguy1221 (talk) 07:56, 29 July 2018 (UTC)[reply]

In "to accelerate a ship of mass m, one needs a force F, there is no way around that except for gravitational slingshots" there is no 'except'. No force == no acceleration. In a gravitational slingshot gravity is the force accelerating the spaceship. Doroletho (talk) 15:01, 29 July 2018 (UTC)[reply]

The chain rule derivative you do looks right. As said above, the first term is F = ma. The other term makes it F = ma + m'v. This extra term distinguishes Newtonian momentum from relativistic momentum. The classic case where this matters is that you can take a particle, put it in an accelerator and keep applying force to it, and after a while v scarcely changes - it's moving near the speed of light. Instead the relativistic mass keeps going up and up. To be sure, relativistic mass, while sensible as ever, is presently out of vogue, and you would be encouraged to do relativistic problems using a different formalism and a different definition of "mass"; hence instead of saying p = mv you say p = γm₀v. But F is still dp/dt, and γm₀ is still relativistic mass. Our article on momentum points at variable-mass system. But you have to watch the assumptions in those problems because mass never just "varies" (apart from the relativistic effects); it always comes or leaves taking its own momentum with it. Wnt (talk) 15:00, 29 July 2018 (UTC)[reply]

Sonorescence

The old Chambers Dictionary from 1908 defines sonorescence as the property of emitting sound under intermittent radiant heat or light. I can find this mentioned in some older books, e.g. Rubber World vol. 68 (1923): "In this application hard rubber is particularly valuable owing to the accuracy with which it can be machined and also to its remarkable sonorescent quality." Yet Wikipedia has no entry for sonorescence and I've never heard of this property before. Is it real, or was it an old erroneous belief? Does it have a different name today? Equinox ◑ 16:34, 29 July 2018 (UTC)[reply]

According to the latest OED (draft third edition of June 2017) the term is now obsolete, but the definition was: "The production of audible sounds by a substance when it absorbs periodically modulated light (or other electromagnetic radiation); the ability of a substance to do this." The OED also comments: "Now sometimes called the optoacoustic or photoacoustic effect." Dbfirs 16:39, 29 July 2018 (UTC)[reply]

Thanks; just made a redirect. Equinox ◑ 16:42, 29 July 2018 (UTC)[reply]

You beat me to it! Dbfirs 16:43, 29 July 2018 (UTC)[reply]

Different expression levels from same reporter inserted into the same place in the genome

I used homology directed repair to get a cassette expressing a fluorescent protein and (eukaryotic) antibiotic resistance gene in a specific place in the genome of a cell line. The cells were cultured under selective medium but for some reason they all show different levels of expression of the fluorescent protein. Why might that happen? It would be interesting to culture them in a live cell imaging microscope to see if high-fluorescence cells divide into high-fluorescence daughter cells but I'm not going to have the opportunity. The cells in this image are fully confluent because I was about to extract the DNA from them but the variation in expression exists at lower confluence also.

Maybe it's an oversimplification to think they're all the same cells and they actually have developed their own epigenetic deviations which have resulting in the differing expression? They were all resistant to that antibiotic though and the antibiotic was expressed from the same transcript as the fluorescent protein via a 2A sequence. --129.215.47.59 (talk) 18:33, 29 July 2018 (UTC)[reply]

This is the expected result for most things. I mean, not necessarily that level of variance between clonal cells, but variance in general. "Stochastic gene expression" is virtually an entire field of study at this point. I would recommend going to your favorite research search engine and search for recent reviews on that topic. The stochasticity can arise from transcription factor abundance/activity/binding, epigenetic marks, transcript stability, or translation rates. Or even protein stability. It's a whole field! Some genes are more prone to this than others, and variance can also be influenced by environmental factors and genetic background. If the cells were recently transfected and not subject to clonal expansion yet, whether the transgene is likely to be identical in each would depend on the method by which you got it in there. Someguy1221 (talk) 02:24, 30 July 2018 (UTC)[reply]

This [maybe not -- see below] likely has to do with heterochromatin formation or other epigenetic aspects of the genome. See position-effect variegation as one example, though to be sure I don't know whether you have yours next to heterochromatin. Note though that putting multiple copies of something into the genome will make heterochromatin; it's the body's despamming mechanism. Steve Henikoff put out a lot of the key papers in the area. There are some neat examples - the Pigmented Extraepidermal Tissues mutant reportedly formed five different sublineages with different (internal) pigmentation patterns from a single originating mutant [4] though four were lost during an air conditioner outage. I should also comment that "unstable transgene expression" is typically downward and hence disappointing - it was not that uncommon for lines of transgenic mice to just stop producing the transcript as a new heterochromatin region became established, though modern methods allow for better control over both the position and the number of copies.

Actually looking at your picture though, I realize this might be simpler than my first thought. It is possible that some variable aspect of the plating is influencing the expression -- for example, the cells might be at different points of the cell cycle, or some might be experiencing contact inhibition while others aren't, or many other things. The effects I described above should be somewhat clonal in nature, but it looks like you grew up those cells together, and there's no obvious correlation between neighboring cells. There's a lot of variation, but not variegation. If I saw patches of lower expression it would be more likely to be a DNA-based effect. See if you can synchronize these cells in the cell cycle and look at them at known times and/or with cell cycle markers as controls. Wnt (talk) 14:29, 30 July 2018 (UTC)[reply]

There is of course the far more straightforward explanation that your cultures aren't pure. There could be differential uptake/expression of your contruct in different cells. What cell line is it supposed to be, and have you checked that lately? Cell line contamination is a major issue (and one of the many reasons I only work with primary cells). Fgf10 (talk) 07:06, 31 July 2018 (UTC)[reply]

July 30

Is the average unpalatability of the plant kingdom (not counting parts the plant wants eaten) increasing over time?

Some have evolved thorns, needles (i.e. pumpkin stems), itching chemicals, poison etc. to discourage being eaten. Nonetheless this is far from universal. Are the undefended species mostly ones where resources are more effectively used for other things like "more seeds" or are they mostly "herbivore defense mutation hasn't happened yet"? If the latter then it seems plausible that if evolution were allowed to proceed for hundreds of millions of more years without human interference then there should be more biomass with anti-herbivore/omnivore defenses by then. Maybe even a reduction in the amount of far-apart, not that sharp thorns in favor of closer-spaced sharper ones. Sagittarian Milky Way (talk) 19:33, 30 July 2018 (UTC)[reply]

Your proposition assumes that plants would evolve while herbivore animals would not; however, "unpalatability" is a moving feast: see Coevolution. {The poster formerly known as 87.81.230.195} 90.217.102.16 (talk) 20:05, 30 July 2018 (UTC)[reply]

Is defense getting better then? And offense too of course (poison resistance, tougher mouths etc.) Sagittarian Milky Way (talk) 20:19, 30 July 2018 (UTC)[reply]

Err . . . yes, but so is attack. Did you not read Coevolution#Predators and prey? OK, try Evolutionary arms race. All this is Evolution 101. {The poster formerly known as 87.81.230.195} 90.217.102.16 (talk) 22:52, 30 July 2018 (UTC)[reply]

If I see 300 million AD and every plant is covered in glass fur I'd still consider defense increased even if it makes no difference in relative terms (the evolutionary arms race). Would be interesting to see what can eat that though. Sagittarian Milky Way (talk) 23:39, 30 July 2018 (UTC)[reply]

Herbivory is not the only selection pressure that operates on plants. Plants compete with each other, and other organisms, for access to resources. They also have to withstand attack by fungi and microbes. Defenses against any of these are not free to the plant, and thus plants' phenotypes will change over time based on the balance between different selection pressures. Of course this works the other way around too! You can probably find at a nearby grocery store fruits produced for consumption by animals that no longer exist. They only haven't gone extinct because the plant got lucky and was "adopted" by humans, who can propagate the plant without eating the seeds.

There's not really any objective way to quantify "more" or "less palatable". Thorns might make you less inclined to eat a plant, but they make little difference to giraffes, which have thick tissue covering their palates for consuming thorny plants, or to insects crawling around on the plant. There is no "ultimate goal" evolution is working towards, so saying "herbivore defense mutation hasn't happened yet" doesn't make sense. --47.146.63.87 (talk) 03:58, 31 July 2018 (UTC)[reply]

The avocado thing is interesting. Here's an article though that talks about it ... the article also says that there are wild avocados that wouldn't be recognized as edible, which have apparently survived the 13,000 years since extinction of megafauna. They make a bunch of handwavey arguments about jaguars and rodents without AFAICT any proof. It sounds like the theory is perhaps not altogether complete... Wnt (talk) 14:19, 1 August 2018 (UTC)[reply]

So why don't say maple leaf stems have thorns or noxious chemicals like poison? Has it been tried but other maples were more successful and it never caught on or is it more likely that a thorny maple hasn't existed yet? (("thorn mutation never happened" (in that species)). I've heard THC was invented to be sunscreen. This was useful and cheap enough to catch on (to wild THC percents, not the extreme THC percents of modern breeding of course). But neighboring plants that can't reproduce with cannabis don't have it so it seems like useful mutations can just be too rare to have happened by 2018 AD. If so then it'd stand to reason that there's species that would probably select for THC or poison or thorns or whatever if only that mutation would happen and give it a few hundred million more years of uninterfered with evolution and some of these mutations that'd be selected for but haven't happened yet would happen and spread right? Sagittarian Milky Way (talk) 06:55, 31 July 2018 (UTC)[reply]

It takes energy to make thorns or poisonous substances. And there are different protective mechanisms, eg attracting animals like ants that may defend the plant, hard impenetrable bark. Also thorns will not stop small herbivores like caterpillars or beetles. Dumping all the leaves every year also will disrupt the animals that depend on eating them. Some weeds will just grow and flower very fast. Graeme Bartlett (talk) 07:54, 31 July 2018 (UTC)[reply]

Chemical elements and the next, nearest one

I'm just completing my knowledge of chemistry and need to ask one last thing:

When an element, say gold, becomes gold, does it become gold from an adjacent element on the periodic table, because it got an extra bit, or lost an extra bit? A yes or no is fine, if you like.

Many thanks,

Anna Frodesiak (talk) 21:28, 30 July 2018 (UTC)[reply]

In general, both are possible. For example, through:

Alpha decay in which the element's atomic number decreases by two (and mass number by four)
Beta decay in which the element's atomic number increases by one (mass number remains constant).

For gold in particular, see Synthesis of precious metals#Gold. Some rare isotopes of platinum, thallium etc, do decay into gold naturally, too. Abecedare (talk) 21:43, 30 July 2018 (UTC)[reply]

Thanks, Abecedare. Ah, so gold can come into existence from thallium without mercury ever being involved, right? Anna Frodesiak (talk) 21:51, 30 July 2018 (UTC)[reply]

Yes. For example, ¹⁸¹Tl alpha decays into ¹⁷⁷Au (which itself is unstable and will soon decay into isotopes of platinum or iridium). Abecedare (talk) 22:02, 30 July 2018 (UTC)[reply]

Looking at the wonderful chart at [5], which, be warned, is going to simply vomit tremendous amounts of information at you... I see that the one stable isotope of gold, ¹⁹⁷Au, can be arrived at from beta decay of ¹⁹⁷Pt, and electron capture from ¹⁹⁷Hg. There are many unstable isotopes of gold that are themselves parts of other decay chains. As you can see at Isotopes of thallium, a number of thallium isotopes can decay by alpha emission directly into gold, but all of these yield unstable isotopes that then further decay into something else. Someguy1221 (talk) 21:58, 30 July 2018 (UTC)[reply]

You two have answered my question indeed. And wow, that link is really quite something. Thank you both. Anna Frodesiak (talk) 22:08, 30 July 2018 (UTC)[reply]

Gold atoms are from supernovas. Not every last gold atom of course. Supernovas are hot enough to turn materials no heavier than iron-56 into gold-179 and even uranium-238 I think. They make the centers of stars look like freezers. Sagittarian Milky Way (talk) 23:50, 30 July 2018 (UTC)[reply]

In our supernova nucleosynthesis article, there is a chart [6] that shows the origins of each element. It indicates that most gold is produced by neutron star mergers, with a small amount from dying low mass stars. It doesn't appear that any significant amount of gold comes from supernovae. CodeTalker (talk) 00:54, 31 July 2018 (UTC)[reply]

Exactly how much of the r-process yield we see comes from supernovae and how much comes from merging neutron stars is still under discussion according to the article; certainly until recently the major site of the r-process was thought to be supernovae. The yield from low-mass stars is from the s-process. Basically, most isotopes of heavy elements can be produced in two ways, both of which involve neutron capture. One way is the s-process (s for slow neutron capture); there a seed nucleus (iron if you like) slowly captures neutrons one at a time. After a few it gets a neutron excess and becomes unstable to beta decay, a neutron converts to a proton, and we have the next element. The other way is the r-process (r for rapid neutron capture), where the seed nuclei are spammed so quickly by neutrons and they have no time to beta decay until the neutron drip line (the point at which a nucleus will not capture and retain another neutron, as its binding energy would be zero). The r-process tends to produce more neutron-rich stable nuclides and the s-process tends to produce the ones closer to the middle (there are also a few proton-rich stable nuclides called p-nuclei whose origin is still a little mysterious), but many nuclides (like gold-197) can be produced both ways. Only for the very heaviest elements (thorium and uranium) does the r-process alone contribute, because the elements between bismuth (83) and thorium (90) are very unstable, and the s-process does not spam neutrons fast enough to cross this gap; that is why thorium and uranium are quite rare in the Universe (qnd what does get produced slowly decays away). Double sharp (talk) 01:33, 31 July 2018 (UTC)[reply]

I do not see supernovas in that chart. Anna Frodesiak (talk) 03:54, 31 July 2018 (UTC)[reply]

Exploding massive stars are supernovas. Graeme Bartlett (talk) 07:49, 31 July 2018 (UTC)[reply]

Ohhhhhhhhhhhh, really?...of course I knew that. :) Anna Frodesiak (talk) 10:27, 31 July 2018 (UTC)[reply]

Wikipedia has an article titled supernova that can help you learn more about the subject, especially stuff that you hadn't already known. --Jayron 32 15:13, 31 July 2018 (UTC)[reply]

Trying to give a more general answer without too much jargon. Helium is produced by fusing protons (in other words, hydrogen-1 nuclei) together. Some of the protons then change to neutrons. Most helium was produced this way in at the beginning of the universe. Stars produce more helium by the same mechanism. The majority of elements after that up to nickel are produced in stars by more fusion, which successively adds alpha particles, a.k.a. helium-4 nuclei. This means protons get added two at a time, which is partially why elements with even atomic numbers are more common than odd. The elements after nickel are, as others have expounded on, mostly made from bombardment of nuclei by various particles, most often neutrons. This occurs in a variety of processes, such as supernovas. See the nucleosynthesis article for all the gory details. These processes occur much less often, and fusion of elements after nickel uses up energy instead of releasing it, so these elements are much rarer. Also, when radioactive nuclides are produced, they eventually decay, which (usually) changes them into other elements. Quite a few nuclides are only produced (at least in nature) by this mechanism. As also discussed above, the products depend on the parent nuclide and type of decay. --47.146.63.87 (talk) 07:33, 1 August 2018 (UTC)[reply]

How is the optical effect called when you laquer carbon fiber?

How is the effect called when someone laquers carbon. i jknow in wood it means chayotance but i never find anything related to carbon. i can only find depth effect but i think not that this is the right word to use. — Preceding unsigned comment added by Saludacymbals (talk • contribs) 21:32, 30 July 2018 (UTC)[reply]

See the article Chatoyancy that describes the reflectance effect in gemstones and treated wood surfaces. Chatoyant carbon fiber is advertised, see video., and has been used in knife handles, see video. DroneB (talk) 23:57, 30 July 2018 (UTC)[reply]

thats the wrong answer..i meant when carbon fiber is laquered several times the structure has a 3 dimensional effect and i dont know the right word for it

July 31

croaking frog stopping

1. Is 'croaking' sound by a single frog possible or is that always in chorus or group? 2. Will that croaking sound stop momentarily when someone crosses closely to a croaking frog? Thanks.

1 dunno 2 yes. At least in Australia. Greglocock (talk) 12:27, 31 July 2018 (UTC)[reply]

It will depend on the species, though there is much commonality in the behavior. For example, when I've encountered the American bullfrog, as it is rather large, the number of individuals in a chorus tends to be small, so I've certainly heard one forlorn bullfrog calling without apparent response at first. As that article says, "choruses are dynamic", which is to say, they have to start (and end) somewhere. My experience with frogs going silent is that it seems to be based on line of sight; I've stood just on the far side of a barberry bush and listened to a chorus of wood frogs clucking away, but often frogs will go silent even from 20 or 30 feet distant if they see me. Wnt (talk) 12:46, 31 July 2018 (UTC)[reply]

Yes and yes. Frog#Call has "Males may call individually or there may be a chorus of sound where numerous males have converged on breeding sites." A tree frog found its way into my house a few years ago and sang quite a bit all by itself. (No citation for the answer to the second question, but I have observed it hundreds of times.)--Wikimedes (talk) 05:10, 2 August 2018 (UTC)[reply]

Shark in bleach solution

In this story it refers to the shark being put in a bucket with a bleach solution.

I couldn't work out whether this was supposed to be amateurish/cruel (a bucket that's previously been used for cleaning, filled with water) or clever/pre-planned (a bucket deliberately filled with a liquid a shark would be comfortable with).

I suspect the former (surely bleach harms most creatures?) but am unsciency enough (I refer you to my last use of brackets) to recognise it may be the latter.

Which is it? --Dweller (talk) Become old fashioned! 14:05, 31 July 2018 (UTC)[reply]

You've presupposed intent with regard to the bleach solution, which is not evident from the text. An equally likely explanation is that the people who stole the shark grabbed a random bucket, which had previously been used to mop a floor with, and thus contained a bleach solution, threw the shark into it, and attempted to walk out. Nowhere in the article does it state that the couple intentionally used bleach or even knew the bucket contained the bleach. It's always good to make the fewest assumptions possible, and to not explain things which are themselves not established as true first. See Occam's razor. --Jayron 32 14:09, 31 July 2018 (UTC)[reply]

I thought I had that covered with "amateurish ... a bucket that's previously been used for cleaning, filled with water" but if by including "cruel" (I think stupidity/lack of deliberate malice doesn't necessarily make things not cruel) I didn't make it clear enough, that was indeed one of the two options. --Dweller (talk) Become old fashioned! 14:17, 31 July 2018 (UTC)[reply]

Why yes you did. My apologies for not reading your question more carefully. I was rude, and for that I apologize. --Jayron 32 15:12, 31 July 2018 (UTC)[reply]

And now you were lovely and for that I'm very grateful. :-) --Dweller (talk) Become old fashioned! 15:37, 31 July 2018 (UTC)[reply]

Here's a news article from (sort-of-) local news channel NBC 5 Dallas/Ft. Worth: Horn Shark Found After Being Stolen From San Antonio Aquarium, including a lengthy interview video with the local police. Describing the shark's health and condition: "...Luckily, the thief was somebody who knew what he was doing..." according to Leon Valley Police Chief Joseph Salvaggio. The police chief declined to discuss questions that were specifically about the bleach solution.

Here is more coverage from KSAT San Antonio: Shark stolen from San Antonio Aquarium is rescued.... "Spellman (General Manager lf the San Antonio Aquarium) said that the bleach solution the shark was placed in might have shocked the shark's system, which made aquarium staff and authorities uncertain if the shark would survive the heist. But, to the surprise of police and aquarium staff, the shark was in good health when it was returned Monday night."

Nimur (talk) 14:21, 31 July 2018 (UTC)[reply]

The CNN version of the story is kind of oddly worded, but I inferred that they had dumped the bleach first.[7] ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:00, 31 July 2018 (UTC)[reply]

Great detective work, Bugs. Curious stuff. I love this: "The police chief declined to discuss questions that were specifically about the bleach solution.". I'm going to stick with amateur/unintentionally cruel for now. --Dweller (talk) Become old fashioned! 15:39, 31 July 2018 (UTC)[reply]

There are various kinds of bleach. I think a chlorine bleach such as Clorox is going to be harmful to just about any living thing. However, oxygen bleaches such as OxiClean are relatively nontoxic if the concentration isn't too high, and might even provide some oxygen to the shark. Looie496 (talk) 16:29, 31 July 2018 (UTC)[reply]

The first story I remember seeing said that the thieves "emptied out a bleach bucket".[8] When covering a current event on Wikipedia, I always try to get the first story I can find because it is the most detailed and comprehensible - after that there are a thousand glommers-on that just garble the facts. But it gets harder and harder to find them because the news spammers get better at making it look like they published the story last March. Anyway, I would assume that they not merely emptied out the bleach bucket, but rinsed it also. Wnt (talk) 19:11, 31 July 2018 (UTC)[reply]

Apollo 11 splash down module

My son has seen a LEGO model of the Saturn V rocket. The module that splashed down is faithfully recreated in the LEGO. My son would like to know what the 3 ball shaped objects are at the top of the module and why there isn't a 4th one. A simple schematic diagram that is comprehensible to a child would be peefect, text is fine too. --Dweller (talk) Become old fashioned! 21:10, 31 July 2018 (UTC)[reply]

See Apollo Command Module#Earth Landing System. The Command Module contained "three inflation bags for uprighting the capsule if necessary"; I suppose that they had to be asymmetrical (three bags rather than four) to successfully turn the module over in the water (i.e., to float only one side of the module). In the Apollo 11 mission they had to be used to right the module after splashdown, and that's why they are deployed in the photo you linked. Deor (talk) 22:04, 31 July 2018 (UTC)[reply]

Technical details can be found in the Apollo Spacecraft News Reference book, Section 12 - Earth Landing Subsystem, written by North American Rockwell circa 1972 as a reference encyclopedia for news and media reporters who wanted to cover factual data about the Apollo missions. Page 96 has some great diagrams of the CM Uprighting System with the infamous "Stable II" diagram and the center of gravity for the capsule.

This information was easily discoverable from the main Apollo Lunar Surface Journal website, the official online NASA record of the lunar surface operations. I recommend reading the ALSJ early and often.

For any interested rocket scientist/nautical-engineering nerds in our audience: the difficult calculation of the metacentric height or "righting arm" problem is a recurring theme in the design of control systems for spacecraft (and boats). In the same way that control system engineers calculate a phase margin during the analysis of control system stability, nautical engineers calculate an equivalent property that directly corresponds to the geometric phase angle of a rocking vessel.

Failure to engineer an acceptable phase margin - and failure by the captain to account for stability margin degradation during severe icing conditions - was the cause for the Destination tragedy that recently made the front page of the NTSB's Major Investigations website. "The NTSB’s Marine Accident Brief 18-14 states the probable cause for the sinking was the captain’s decision to proceed during heavy freezing spray conditions without ensuring the vessel had a margin of stability to withstand an accumulation of ice..."

This is all just a fancy way to say that "it tips over in the water because it's not balanced correctly;" but when engineers say it, they do it with technical diagrams and equations and heel angle charts that account for the distribution of weight and loading on the interior of the vessel, in all orientations. This is all great reading material for your Lego-infatuated future astronaut - especially if they plan to keep the minifigs safe during the mission! Never forget the important lessons standardized in NASA Handbook 8709.24 - "Promote and sustain a strong safety culture at all levels of the Agency"!

Nimur (talk) 00:26, 1 August 2018 (UTC)[reply]

Yes, the Apollo Command Module could be nose down after spashdown (called "stable 2 position". The bags inflate to right the spacecraft. It looks like there was some stuff that prevented having four bags, but the photo I added only seems to have two. Bubba73 ^{You talkin' to me?} 01:22, 1 August 2018 (UTC)[reply]

There are only two visibly-inflated bags because your photo is the Columbia (the CM from Apollo 11), photographed in its present museum set-up, which - for historical and educational purposes - is recreating the famous Stable 2 with Only Two Flotation Bags Inflated situation that occurred on July 24, 1969. Here's the transcript for ALSJ Apollo 11 - Reentry.

“

This is Photo One. The 3 (garbled) is (garbled) plus 20 feet and two flotation bags are visible at this time. The (garbled) to go to 4. (garbled) Module (garbled) above the other (garbled) of the vertical axis (garbled).

”

— Photo 1, one of the US Navy Sea King recovery helicopters

“

Hornet, I didn't copy Photo 1's full report. Understand 2 flotation bags deployed and in stable 1 now. Is that correct? Over.

”

— U.S.S. Hornet, the aircraft carrier charged with recovery, via ALSJ

“

This is Air Boss 1. Photo 1 says that it is still in stable 2. The bags are inflated. It is not absolutely inverted now, it's 70 degrees to the vertical axis. Still stable 2.

”

— Air Boss, the commander on scene in a US Navy electronic warfare aircraft, via ALSJ

“

The Command Module [garble] quite well [garble] vertical axis of [garble] downwind [garble] 10 degrees. [Garble] the flotation collar [garble] to Photo 1. The uprighting bags. 2 are fully inflated, 1 is partially inflated.

”

— Swim 2, one of the US Navy Sea King recovery helicopters, via ALSJ

Meanwhile the astronauts were inside, safely strapped in, upside down, politely completing their checklists and waiting for Air Boss to order the swimmers into the water. Nobody ever said it was easy to go From the Earth to the Moon, Around the Moon, and return to Earth again!

Nimur (talk) 02:52, 1 August 2018 (UTC)[reply]

This is great stuff, thank you very much. --Dweller (talk) Become old fashioned! 16:54, 1 August 2018 (UTC)[reply]

Your son may also be interested in learning that a similar crew module uprighting system is used on Orion, the capsule NASA is currently developing for an eventual return to the vicinity of the Moon. Orion (a larger capsule than Apollo) uses five airbags, but during its 2014 flight test only two of the five functioned properly, with one airbag failing to inflate and two failing to hold pressure. [9] In 2017 NASA tested the redesigned system under a number of failure modes, and this post shows a capsule rolling upright under four inflated airbags. -- ToE 22:35, 1 August 2018 (UTC)[reply]

Antifungal cream

Today I ran across a tube of antifungal cream that I'd bought some time ago, and I glanced over the ordinary warnings and how-to-use directions. I was surprised to see a note this product is not effective on scalp or nails. Fingernails I can understand, since they're structurally a good deal different from soft ordinary skin. But from the perspective of a fungal infection, how is the scalp so different from ordinary skin that clotrimazole is unable to treat the infection effectively? Google has pages on how to handle scalp fungus, but no explanation. I ran a quick Medline search, and I saw a couple of articles (DOI 10.1002/14651858.CD008138.pub3 and al-Fouzan, A.S., et al. "Dermatophytosis of children in Kuwait : a prospective survey". International journal of dermatology 32.11 (1993): 798-801.) that seem to conclude that topical use of clotrimazole was better than placebo at treating fungal infections of the scalp, so I'm even more confused. Nyttend (talk) 22:23, 31 July 2018 (UTC)[reply]

It's interesting, yeah. Even clinical trials I could find on clotrimazole going back to the 70s, at least the larger ones, actually excluded nail and scalp infections from their patient groups. I suspect this might be due to griseofulvin being an older drug that is proven both safe and effective for these cases. That is, it is relatively unusual for a patient to present with a scalp fungus that cannot be adequately treated by the standard of care, so unless you really enrich for such patients, it's tough for a proposed trial to pass review. In this small clinical trial, griseofulvin was compared to itself plus clotrimazole against a scalp fungus, and no significant improvement was found (though simultaneous treatment with selenium sulfide appeared to hasten the elimination of viable spores). Someguy1221 (talk) 22:36, 31 July 2018 (UTC)[reply]

Yes, for regulated drugs, the labeling has to follow the relevant laws and regulations. In most jurisdictions with meaningful regulation of drugs, drug labels can't claim uses for anything not approved by the regulator. So it might simply mean the drug has not been approved for nail or scalp infections. If it's still effective, the label can't tell you that, but in most places medical professionals can prescribe it to you off-label. The lack of approval is often because of a lack of incentive for anyone to go through the rigors of the drug approval process for a new indication. A big example is aspirin. Even though we know it's very useful for prevention of cardiovascular disease, at least in the U.S., you won't find that on the label of any aspirin product, because it hasn't been approved by the FDA for that use. Hence, all use of it for anything other than pain relief is off-label use. --47.146.63.87 (talk) 07:59, 1 August 2018 (UTC)[reply]

I mostly agree with you but I'm not sure if your statements on aspirin are entirely correct. See [10] [11] (maybe also [12]) [13] [14] [15]. As I understand it, the FDA has approved the use of aspirin for secondary prevention of cardiovascular disease i.e. in those who have already experience a cardiovascular event. They have not approved it for primary prevention. Also the information on usage for secondary prevention is only targeted at health professionals. So using aspirin for secondary prevention under the guidance of a doctor or other professional is not off-label. Using it for primary prevention would be, even I think with many indications/known risk factors e.g. family history, age, diet, exercise and whatever else which may lead to many professionals recommending it. Nil Einne (talk) 18:03, 1 August 2018 (UTC)[reply]

Oh hey, interesting. I wonder if the FDA standards are different for what can be stated in things for medical professionals as opposed to the general public. --47.146.63.87 (talk) 02:32, 2 August 2018 (UTC)[reply]

The laws that regulate drug advertisement are very complicated, at least in the USA; our regulatory agency, the FDA, has "different ways to enforce the laws." Here's a lengthy FAQ website, including answers to How can an ad violate the law?

"Prescribing information"... "is written for healthcare providers"; certain types of advertisement only need to contain a "Brief Summary", which is "...the technical name for the detailed information that appears in ads for prescription drugs." Both types of information are regulated by FDA.

Nimur (talk) 06:58, 2 August 2018 (UTC)[reply]

August 1

Why is blood pH 7.4

I can’t find this in Wiki;

What makes (human) blood alkaline?

I would have thought dissolved CO₂ would result in an acidic level.

It seems being alkaline helps prevent disease, and hinders cancer, but what makes it alkaline? One article says breathing too slowly (shallowly) lowers pH, breathing too fast (hyperventilating) raises pH - implying that Oxygen raises pH.

So does that mean pH in veins is significantly lower than in arteries? Does pH vary with hunger - ie how long since you’ve eaten? MBG02 (talk) 04:34, 1 August 2018 (UTC)[reply]

Our article Acid–base homeostasis contains some discussion of this. Double sharp (talk) 05:56, 1 August 2018 (UTC)[reply]

Breathing faster acts to raise pH because you're getting rid of CO₂. A lower respiratory rate lowers pH because you're retaining CO₂. It's not about the oxygen. Venous pH and arterial pH generally agree very closely ( one study showed aterial mean of 7.384 and venous mean of 7.369. [16] - Nunh-huh 07:21, 1 August 2018 (UTC)[reply]

Blood is kept alkaline by a whole bunch of body mechanisms, as detailed in the aforementioned article. Your blood contains chemical buffers that automatically compensate against changes in the blood composition that would otherwise significantly change its pH. The body also monitors blood pH, and can alter the blood composition if needed. As mentioned, this means blood pH is almost identical throughout the body, despite differences in blood composition.

As to why, well, the straightforward answer is given in acid–base homeostasis: your body's components stop working properly if the pH changes significantly. You stated, It seems being alkaline helps prevent disease, and hinders cancer. What are you basing this on? It sounds like you might have read some alkaline diet nonsense. Cancer cells do usually produce a more acidic microenvironment, but this does not automatically mean the increased acidity causes cancer. For the ultimate cause, I recall reading somewhere that it's believed because life on Earth first emerged in alkaline oceans, cells are adapted to an alkaline environment, which makes this a kind of evolutionary path dependence, but I'm not sure how well-supported that hypothesis is. Anyone know of some sources discussing this? --47.146.63.87 (talk) 07:52, 1 August 2018 (UTC)[reply]

Thanks for your answer, I think the disease/cancer/alkaline diet point was important. About your last question, an interesting question is whether the blood pH is reflective of intracellular pH. I found [17] which says cytosolic pH is nearly neutral, and also some other organelles. Look at this source, it seems it was taken as 7.2 [18]. Something similar is also mentioned in Cytosol, in particular giving a range of 7.0-7.4 in humans. (I missed it since I was earlier searching for info related to you suggestion and was getting a lot of alkaline diet etc nonsense so changed to Google Scholar.) This source suggests 7.4 may be a little high to reflect conditions in most species [19]. Maybe also of minor interest [20] [21] Nil Einne (talk) 18:50, 1 August 2018 (UTC)[reply]

The body made CO₂ as a waste product which would tend to make plasma acidic; however, the kidneys make bicarbonate, and plenty of it ... at around 25mM in the plasma, that's the second-most prevalent anion. Klbrain (talk) 23:34, 1 August 2018 (UTC)[reply]

In brief, CO2 + H2O <-> H2CO3 <-> H+ + HCO3- <-> 2 H+ + CO₃^2-. The bicarbonate buffer can accept large amounts of acid or base and change only slightly in pH; hence the body can set it to pretty much whatever pH it wants, then keep that pH in the face of minor metabolic adversity (enough pushing on it and eventually you get to acidosis or alkalosis anyway). (Lab chemists do the same, adding drops of acid or base to get the buffer to the pH they want) Note that CO2 gas per se doesn't affect pH; it's only when it interacts with water. But if it's dissolved in water it will interact with water. I think 70% of the CO2 is as bicarbonate and 10% as dissolved gas, but I may not remember that right. (Some sticks to carboxyhemoglobin) Note all the proteins in blood and even in blood cells also have a buffering effect on pH. Wnt (talk) 00:31, 2 August 2018 (UTC)[reply]

One minor quibble with the above answer; "the body can set it to pretty much whatever pH it wants" isn't really all that true. All buffer solutions have two measurements that determine the pH range over which they can be effective, and "any pH it wants" is far too broad. The pH range is determined by 1) the equivalence point of the buffer in question (see Henderson–Hasselbalch equation); which is where the pH of the buffer equals the pKa of the acid form; this defines the center of the effective range. 2) The concentrations of the buffers in question, known as the "buffer capacity", which determines the size of the pH range around that center point where the buffer will still, you know, buffer. The effective pKa of the CO2/Carbonic Acid system is about 6ish, and the concentrations in the blood are fairly low, which means that at 7.4, our buffer system is already probably nearing the limits of its truly effective range. I would be shocked if you could push the equilibrium pH to past 8 or so before the buffer broke down. Otherwise, however Wnt's answer is solid. BTW, the Henderson–Hasselbalch equation article contains a nice use of the equation to calculate physiologic pH. --Jayron 32 12:40, 2 August 2018 (UTC)[reply]

Botany: Can you help me identify this plant spotted in my mum's garden in Switzerland?

My mother has found a plant in her garden that she can't identify. It is located in Switzerland, in the countryside, altitude 635 meters. The plant seems to attract a lot of insects: bees, wasps, rose chafers... Photos available in the links below.

Picture 1 Picture 2 31.35.194.25 (talk) 09:12, 1 August 2018 (UTC)[reply]

I'm more familiar with North American plants, but my two best guesses so far are Angelica and Heracleum (Hogweed), though not any specific species I can find. Still looking. --Jayron 32 11:07, 1 August 2018 (UTC)[reply]

Cicuta and other similar genuses (Hemlocks) maybe also and maybe Cicely. Broadly, the flowering and shape reminds me of many of the plants in the Apiaceae, or Carrot/Parsnip/Parsley/Celery family, which I think includes all of the ones I cited above. There are literally hundreds of species in that family, many of which are familiar vegetables, herbs, or spices like Anise, fennel, coriander, etc. There are also poisonous ones (like Hemlock and Hogweed). Sorry I can't get closer than that, but that's the best I've got there. Maybe a real botanist will be along shortly to help... --Jayron 32 11:13, 1 August 2018 (UTC)[reply]

Mystery solved: it's a Seseli gummiferum, a.k.a. moon carrot! OP.80.94.146.48 (talk) 07:28, 3 August 2018 (UTC)[reply]

July 2018 lunar eclipse - visibility

I would like to know if the visibility map is correct. The visibility map was posted in 2014 for a 2018 lunar eclipse. Article says no visibility in north america. I live in southern California, and I was able to see the lunar eclipse. See July 2018 lunar eclipse#Visibility. link to image

SWP13 (talk) 13:06, 1 August 2018 (UTC)[reply]

That visibility map looks correct to me in that it matches what I have seen published elsewhere and (WP:OR here) it agrees with real-time reports from friends in Europe who watched the latter half of the eclipse and reported it ending a few hours before I saw a beautiful non-eclipsed (post eclipse) full moon rise on the East Coast of the US, which should have been a couple of hours before you would have been able to see the moon in California. What did you see that led you to believe you were viewing the eclipse? Might you have seen a cloud block part of the moon making it appear partially eclipsed, or perhaps a haze obscured moon creating the blood moon appearance of the fully eclipsed moon? -- ToE 13:37, 1 August 2018 (UTC)[reply]

Just to note that while a lunar eclipse often causes a blood red color for the moon, it is not the only thing which can cause it, so if our Californian above saw a red moon, it doesn't necessarily mean he saw any of the eclipse. This article explains some of the causes of a red moon, only one of which is the eclipse. The moon could be red because it's low on the horizon (the same reason sunsents are red!). Or it could be red because of certain particulate matter in the atmosphere; that article specifically notes forest fires as a possible source of red coloration to the moon. Smog could be another, both of which California has in abundance right now. --Jayron 32 14:27, 1 August 2018 (UTC)[reply]

>To clarify.. The orange color full moon that I saw was at 8:05pm PDT. The sky was very clear with no smog or clouds. At about 10pm PDT, the moon was very bright white. How does a person distinguish it from the lunar eclipse if the images look so similar? Red Moon article was very helpful. Thank you for confirming the correctness if the visibility map. SWP13 (talk) 22:45, 2 August 2018 (UTC)[reply]

An eclipsed moon isn't only red, but also very dim. Judging from the settings I had to use on my camera, this time at 20:46 UTC about 1/7000 of the brightness of a normal full moon. It's a bit variable. At 20:05 PDT, the moon was very low in the sky in California. Add a bit of smoke or dust close to the horizon (which can still be more than 100 km away from you) and you get a red moon. PiusImpavidus (talk) 09:37, 3 August 2018 (UTC)[reply]

This should have its own header. I should note that the darkening of the sun, the rending of a curtain, even the exhumation of corpses is consistent with a haboob (sandstorm) which certainly seems within the range of possibility. Such a thing can be seen as symbolic without requiring any departure from normal physics. Wnt (talk) 11:51, 3 August 2018 (UTC)[reply]

Why do flies often walk in a saltatory manner? (at least the species I see)

Sagittarian Milky Way (talk) 17:32, 1 August 2018 (UTC)[reply]

Wikipedia has articles titled terrestrial locomotion, gait, and jumping which will give you a starting point for you to research your question. If you don't find the answers in those articles, you can use those terms combined with words like "fly" or "walking" in google to find articles. For example, by typing "fly walking gait" into Google, and searching through some of the results, I came up with this article, which seems by the title to directly address your question. In the future, to get faster results when researching, try those techniques (reading Wikipedia articles, following links from Wikipedia articles, playing around with search terms in Google) and you're more likely to get good results. --Jayron 32 18:11, 1 August 2018 (UTC)[reply]

It is related to the Square–cube law. It takes very little energy to accelerate and decelerate a fly. Therefore, it can quickly move from where it is to where it wants to be. Humans, in relation, require a lot of energy to move from one place to another. So, we appear to move in slow motion in comparison. If you speed up human movement, it will appear as jerky movements from one place to another. You can increase that to elephants, which appear to move slow compared to humans. 209.149.113.5 (talk) 18:22, 1 August 2018 (UTC)[reply]

Saltatory (adj) is from Latin saltatio "dance, hop, leap". Flies tend to fly in straight lines interrupted by sudden directional changes that typically involve an angle change of 90° achieved in 50 milliseconds. It is likely that the same rapid reflexes operate when the fly walks and is at heightened risk from predators and Sagittarian's flyswatter. Fish recognize insects as prey by their characteristic leaping pattern of short movements and pauses. DroneB (talk) 18:29, 1 August 2018 (UTC)[reply]

We dummies might need the Wiktionary definition for saltatory. 2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk) 02:32, 2 August 2018 (UTC)[reply]

The motor control system in insects is quite a bit less sophisticated than the system in vertebrates. Vertebrates have a huge brain structure called the cerebellum that acts to smooth out movements (among many other things). Insects have no comparable structure -- it's more a matter of switching motor patterns discretely on or off. This makes their movements tend to look jerky. Looie496 (talk) 12:57, 2 August 2018 (UTC)[reply]

That's certainly incorrect. The previous replies are largely on target. Abductive (reasoning) 05:14, 3 August 2018 (UTC)[reply]

You seem to be right, ants and roaches don't act like their senses work better while stationary. Though if the monocular/binocular zone makes a German cockroach nervous one/two antenna(s) stop jiggling. I've always wondered if smelling through that taxes its brain. You can use this trick to control cockroach antennas like a light switch. Sagittarian Milky Way (talk) 06:05, 3 August 2018 (UTC)[reply]

Insect motions are smooth at the level of individual wing beats or steps. Their jerky movements are on the several body length scale, and are no different than a squirrel, say, avoiding predation while looking for food. Abductive (reasoning) 07:12, 3 August 2018 (UTC)[reply]

August 2

Explain why these 2 statements are not contrary to each other

According to opponent process, there's no such color as reddish green.

According to RGB color theories, yellow is reddish green. RGB color theories suggest there's no reddish cyan or greenish magenta, but yellow is reddish green. Georgia guy (talk) 23:52, 2 August 2018 (UTC)[reply]

"Even though yellow is a mixture of red and green in the RGB color theory, the eye does not perceive it as such." ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:00, 3 August 2018 (UTC)[reply]

I assume that you've read Impossible color. More than fifty years ago, I tried holding a good red filter to one eye and a good green filter to the other, and I saw in yellow (not reddish green). My interpretation was that the brain (not the eye) interprets roughly equal stimulations of L and M cones as being the colour yellow. I haven't tried rapid alternation between the two colours. Perhaps I might see that differently as being "reddish green". Colour perception is partly learnt and partly hard-wired. Dbfirs 08:26, 3 August 2018 (UTC)[reply]

In a graphics program (e.g. MSpaint) if you select a custom color with red and green at max (255) and blue at 0, you get yellow -- this is not a "perception" of either the eye or brain. 2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk) 14:17, 3 August 2018 (UTC)[reply]

No, it's your brain telling you that its yellow. Absolutely no light of the 580nm range is leaving the monitor. The monitor has zero yellow pixels in it. Your perception of yellow from a monitor is a purely psychological phenomenon. Actually, all of your perception of color is a purely psychological phenomenon. See qualia and color perception. If you really want to get down to it, you have never seen yellow, because your eye is only capable of detecting basically 3 colors; red, blue, and green, and your perception of yellow is dependent only on how much of each of those receptors is stimulated by a particular bit of light. You can stimulate all three with a single wavelength of yellow light, OR you can stimulate all three with varying intensities of red, green, and blue light and you can't tell the difference. Because you don't see yellow. --Jayron 32 14:58, 3 August 2018 (UTC)[reply]

It depends on your definition of "yellow" -- a can of yellow paint has paint that is yellow in color.— Preceding unsigned comment added by 2606:A000:1126:4CA:0:98F2:CFF6:1782 (talk • contribs)

Actually, it depends on your definition of "color". If you're defining color as the psychological sensation that looking at the yellow paint produces, then yes. If you're defining color as a specific wavelength of electromagnetic radiation, then maybe not so much. The relationship between color you perceive when looking at something and the wavelength of the light in question is tenuous at best. --Jayron 32 15:21, 3 August 2018 (UTC)[reply]

Responding to the OP, it's basically a distinction between the eye and brain. On one hand, the eye contains three types of color-sensitive cones, so the signals leaving the eye can be represented using three independent color dimensions, typically thought of as R, G, and B. However, in the color-processing parts of the visual cortex, the signals are recoded into hue, saturation, and intensity. The hue component can be represented as a circle, with four canonical hues spaced equally around it: red, yellow, green, and blue. Looie496 (talk) 02:38, 4 August 2018 (UTC)[reply]

August 3

Material that generates ultrasound, and not sound, when hit

Could a ultrasound drum exists? That is, when hit, it would generate ultrasound and not sound? Could any ultrasound (silent for humans) instrument exist? Does this strike a chord to anyone?--Doroletho (talk) 12:02, 3 August 2018 (UTC)[reply]

A Dog whistle is an ultrasound instrument. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:10, 3 August 2018 (UTC)[reply]

A drum is a membranophone, and there's no reason why one can not be tuned to sounds higher pitched than humans can perceive. The tuning of drums would obey a two-dimensional analogue of Mersenne's laws (which describe the tuning of strings); that is you can alter the diameter, thickness, and tension on the drum head and create any arbitrarily high sound. The problem with doing this with drums is that drums have a very broad musical "bandwidth"; so while you could perhaps create a drum which had significant sound in the ultrasound range would still have some frequency space in the audible range. For an instrument like a whistle, the bandwidth is MUCH tighter, so you only get a narrow band of frequencies. --Jayron 32 18:12, 3 August 2018 (UTC)[reply]

And an old Guinness said the lowest musical instrument is a 64 foot tall organ pipe in Atlantic City that makes 8 Hertz. Sagittarian Milky Way (talk) 19:44, 3 August 2018 (UTC)[reply]

Jangling a bunch of keys generates plenty of ultrasound, but some audible sound too.

Some depends on your definition of "ultrasound". Children can hear frequencies which adults no longer can. Some of the first TV remotes, the 'Zenith Space Command' from the 1950s,[22] used this range of near-ultrasound, generated with by a purely mechanical remote control with mechanical reeds like a thumb piano, and a frequency-sensitive receiver on the set. Andy Dingley (talk) 20:55, 3 August 2018 (UTC)[reply]

August 4

@@ Line 340: / Line 340: @@
 ::::It depends on your definition of "yellow" -- a can of yellow paint has paint that is yellow in color.<!-- Template:Unsigned --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:2606:A000:1126:4CA:0:98F2:CFF6:1782|2606:A000:1126:4CA:0:98F2:CFF6:1782]] ([[User talk:2606:A000:1126:4CA:0:98F2:CFF6:1782#top|talk]] • [[Special:Contributions/2606:A000:1126:4CA:0:98F2:CFF6:1782|contribs]]) </small>
 :::::Actually, it depends on your definition of "color".  If you're defining color as the psychological sensation that looking at the yellow paint produces, then yes.  If you're defining color as a specific wavelength of electromagnetic radiation, then maybe not so much.  The relationship between color you perceive when looking at something and the wavelength of the light in question is tenuous at best.  --[[User:Jayron32|<span style="color:#009">Jayron</span>]][[User talk:Jayron32|<b style="color:#090">''32''</b>]] 15:21, 3 August 2018 (UTC)
+*Responding to the OP, it's basically a distinction between the eye and brain. On one hand, the eye contains three types of color-sensitive cones, so the signals leaving the eye can be represented using three independent color dimensions, typically thought of as R, G, and B. However, in the color-processing parts of the visual cortex, the signals are recoded into hue, saturation, and intensity. The hue component can be represented as a circle, with four canonical hues spaced equally around it: red, yellow, green, and blue. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 02:38, 4 August 2018 (UTC)
 = August 3 =