Wikipedia:Reference desk/Archives/Science/2015 February 22

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February 22

Conjoined twins

In the article on Conjoined Twins, the author does not mention the first successful separation of craniopagus twins which occurred in Johannesburg, South Africa in early January (before 7 January) 1968 Shirley and Catherine O'Hare were separated and Shirley is still alive Catherine died at 10 months old from a heart complication. I would assume that as the twin that died did not die on the operating table or as a direct result of the operation that this would qualify as the first successful separation of craniopagus twins. Am I correct? <South African Medical Journal 27 April 1968 "Separation of Craniopagus Twins" pp. 412 - 424> <Advance News (Ogdensburg, NY) 7 January 1968 p. 18> <Saturday Star (Johannesburg, South Africa) 14 February and 21 February 2014> KJBrookes (talk) 08:47, 22 February 2015 (UTC)

That would depend on what the sources have to say about it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:17, 22 February 2015 (UTC)

It would be better to discuss this on the Talk page of the article itself rather than here. SteveBaker (talk) 15:36, 22 February 2015 (UTC)

Citation for Yang-Mills Theory - Mathematical Overview

Hi, I'm currently conducting a research review as part of my undergrad degree on classical gauge theories. All the books and articles I've found have assumed the fact quoted in the article (https://en.wikipedia.org/wiki/Yang%E2%80%93Mills_theory#Mathematical_overview) that "the transition between "upper" ("contravariant") and "lower" ("covariant") vector or tensor components is trivial for a indices" but none of the primary sources I've found explicitly state it and the fact is provided in the article without citation.

As far as I can tell, user Pra1998 added it back in 2009 but it's never had any citation and I was wondering if anyone (i.e. Pra1998) could point me in the direction of a citation. — Tjlr2 (talk) 18:57, 22 February 2015 (UTC

Pra1998 has provided an answer elsewhere — Tjlr2 (talk) 19:09, 22 February 2015 (UTC)

Animal species with biological ornaments in females

Are there good sources about animal females (vertebrates and/or invertebrates) who have more or less elaborate biological ornaments to attract and claim males for mating (given the stated rarity in biological_ornament#Female_ornamentation)? Brandmeister^talk 18:56, 22 February 2015 (UTC)

Females will show receptivity to mating by displaying and chimps in estrus have red rumps.soure I am not sure if this counts as ornamentation, though. μηδείς (talk) 01:15, 23 February 2015 (UTC)

A websearch for "drab male, ornate female" sans quotes showed that the three phalaropes have brightly coloured females, and the males are duller. The females also fight over mating rights, and males do most of the incubation and chick care. I suspect there are other species that are similar (seahourse males also look after the fry, but there is no sexual dimorphism). LongHairedFop (talk) 09:38, 23 February 2015 (UTC)

Homo sapiens have the 'drab male'/'ornate female' thing going on, but that's not biological ornamentation. Ornamentation that the female of the species adopts comes typically comes from brightly colored items acquired from the environment. SteveBaker (talk) 15:17, 23 February 2015 (UTC)

I'm pretty sure human female breasts count as a biological ornament through a secondary sex characteristic. Though of course there's lots of cultural stuff too that is not so biological. SemanticMantis (talk) 15:41, 23 February 2015 (UTC)

Fair enough :) Brandmeister^talk 22:22, 23 February 2015 (UTC)

We have tons of relevant articles, some of them have examples: sexual selection, sexual dimorphism, biological ornament, mate choice, Fisherian runaway, secondary sex characteristic.

The refs in this article [1] should be very relevant. Here's a paper specifically on female ornamentation in the rock sparrow [2]. I think /female ornamentation/ on google scholar [3] will be a good search to peruse. You will get lots of theory hits, but also examples sprinkled in. Check out the interesting example of conditional female ornamentation in starlings here [4]. Here's a pop-sci NYT write up that mentions a few sources and examples, e.g. the female pipefish.

Evolutionarily speaking, the general understanding is that the selection processes make male ornamentation more likely, as males don't have to invest as much (typically) in reproduction. And that asymmetry in reproductive investment goes back to evolution of anisogamy, itself a subtle and not-completely-understood process. SemanticMantis (talk) 15:41, 23 February 2015 (UTC)

Does higher levels of Testosterone help in recovering lost/damaged tissue, same way it helps increase recovery and growth of muscles etc.?

High levels of testosterone, of course, will enhance physical performance, physical recovery and muscle growth etc... This is known.

But will it have any direct effect on improving and accelerating the rebuilding of lost/damaged tissue??? Lost/damaged tissue should, in theory, recover and rebuild during sleep and rest, while physical exercise will obviously also contribute to that.

But my question is simply, as I have already asked, will testosterone-treatment have a direct positive effect on healing/rebuilding damaged/lost tissue??

2A02:FE0:C711:5C41:65AF:208C:ACFF:471A (talk) 19:03, 22 February 2015 (UTC)

I am by no means an expert on this, but for what it's worth, my dad was prescribed steroids when his hearing in one ear deteriorated, and his hearing in that ear recovered. Of course, If you're planning on taking some sort of medication, you'd better talk to your doctor first. Also, be aware that Wikipedia does not purport to provide medical advice. — SamX‧☎‧✎‧S 22:43, 22 February 2015 (UTC)

I would never take such treatment unattended, nor would I motivate others to do so. There are serious risks and potential downsides involved, at least if one abuses it. I'm simply trying to understand Testosterone's full effect and purpose, and I have not found info regarding how/if it affects regrowth in tissue, even though my instincts tell me it probably must. So I am not asking for medical advice - I am asking for knowledge/enlightenment. Hopefully I can still get that. Thanks. 2A02:FE0:C711:5C41:5C36:E937:98DB:17CA (talk) 09:04, 23 February 2015 (UTC)

• Most of the scientific evidence indicates that testosterone actually has a negative effect on wound healing. See http://www.medscape.com/viewarticle/524313_5 for details. Looie496 (talk) 15:30, 23 February 2015 (UTC)

If you're competing in any sort of organized sport, keep in mind that using synthetic testosterone is strictly banned by anti-doping rules, both in and out of competition. If you're caught, you almost certainly will face a long ban from competition. 101.160.63.123 (talk) 09:02, 26 February 2015 (UTC)

Technology identification

This is the science reference desk for an online encyclopaedia. It is not a forum for the propagation of delusional bollocks.
The following discussion has been closed. Please do not modify it.
Does anybody know the name of the satellite which is used to see people on earth? Does anybody know if it is possible to change television programs with a satellite? Basically this is the issue: Some people used technology upon a person who was watching a television programme. Whatever this person was thinking who was watching the television, the person on the television could hear and understand, and was replying to whatever the guy watching the television was speaking in his mind… I understand that telepathy can be used here. A Satellite is definitely/could be used to view the person's movement who was watching the television. Anything else? -- (Angelos|Angelus (talk) 19:39, 22 February 2015 (UTC)) Someone is trying to fool you. The resolution from satellite orbit is insufficient to identify individuals, and no technology implements telepathy. Signals from a satellite can be used to change TV channels if you have the correct satellite dish and receiver. A webcam fitted into the TV set can spy on the person watching, and the observer can interpret facial expressions and body language, but there is no scientific evidence that telepathy is possible. Dbfirs 21:11, 22 February 2015 (UTC) It is quite common for people with paranoid schizophrenia to believe that things like this are happening to them. Looie496 (talk) 21:28, 22 February 2015 (UTC) Such thoughts are ideas of reference and delusions of reference which are common for people with psychotic illnesses, including bipolar disorder. --Modocc (talk) 03:38, 23 February 2015 (UTC) There are a few satellites out there with resolutions down to around 15 centimeters (six inches). With such technology, you can resolve individual humans. However, you can't identify who is whom. Also, those kinds of satellites have to be in low earth orbit - which means that they can't continually watch a single place - they can take a still image or two, then they're gone. The satellites that can watch one spot continually have to be in a much higher orbit (a "geostationary orbit", and at that height, they can't see individual people. Reading someone's mind, even with sensor stuck right onto their heads, is still more or less impossible. From a distance of a foot away, it's quite utterly impossible - and from orbit, it's not even possible in principle. If you imagine a geostationary satellite even trying to do this, it would need a detector so unimaginably sensitive that it would be picking up those tiny, tiny electrical signals from 100 billion neurons in every one of the roughly 3.5 billion people on the side of the earth that are on the side of the planet that the satellite could detect. That's 350,000,000,000,000,000,000 of the faintest electrical signals - all mixed up together. There is simply no chance that any kind of computer could sort that mess out fast enough to make sense of the results. So, no, this is nonsense. It can't be done...not even with hypothetical futuristic science. The laws of physics don't allow it. SteveBaker (talk) 05:07, 23 February 2015 (UTC) @Dbfirs, Looie496, Modocc, and SteveBaker: I can't make you peeps believe me, but telepathy is real. It is a technology used for manipulation. There is no scientific evidence because you are not suppose to know; just like UFOs. It's quite understanding how using such words as 'paranoid schizophrenia' and 'ideas of reference and delusions of reference' gives you the upper hand of thinking you understand the problem. Realistically, you won't understand until you are put in the position... Remember, some people lie, some people don't. The words you guys have used applies to people with disorders or liars... And about scientific knowledge, I don't know where to start, in short, science only says 'God did it' when it can't find an explanation, but when it does, lol! Thank you all. -- (Angelos|Angelus (talk) 07:09, 23 February 2015 (UTC)) If “there is no scientific evidence because you are not suppose[d] to know”, how do you know? — No, science does not invoke the God of the gaps; it says “we don't know yet.” —Tamfang (talk) 07:57, 23 February 2015 (UTC) No, Angelos, telepathy is not a technology, and only cranks or charlatans claim to use it for manipulation. Don't believe them. The human brain is capable of many levels of self-deception. This is the science desk, so you should expect scientific answers here, and there is no scientific evidence to support telepathy. You might like to read our articles on Mentalism, and Paranormal. Dbfirs 08:35, 23 February 2015 (UTC) Science never says "God did it". Only religious people do that. Science is happy to say we don't know, when we don't. --Lgriot (talk) 13:04, 23 February 2015 (UTC) There is certainly no scientific evidence for telepathy. A gazillion experiments back in the 1960's tried to show it happening, but to no avail. Many people claim to be able to perform telepathy, but none of them succeed when actually tested to see if they really can do it. The James Randi prize offers a million dollars to anyone who can demonstrate telepathy...and nobody has successfully claimed it. Our brains contain roughly 100 billion neurons, and 100 trillion synapses - and they fire at rates ranging from once a second to 200 times per second. So we're probably looking at 10 to 100 quadrillion tiny electrical impulses per second. That's an insanely enormous amount of data - more than all of the cellphones in the entire world! The electrical field that produces is very tiny - and it's the average of all of those pulses - which produces a sea of incomprehensible noise, with just a few noticeable rhythms. It's like if all the people in the world were shouting at once and all of that sound was mushed together into a single stream of sound. It would be impossible to pick out what one person was saying - but you might be able to figure out that the overall volume of sound gets quieter in parts of the world where people are sleeping right now. That's about the level of ability we have to measure what's going on in people's heads right now. Now, to be fair, there are things that we can measure. It's true that with an appropriate headset, it's possible to measure very, very simplistic things about how someone is thinking...which (technically) could be called "telepathy". For example, we can tell whether someone is thinking predominantly mathematical/logical thoughts or not by measuring overall activity levels on the left and right sides of your head. This kid's toy and a couple of others like it can actually do that! We can also tell how 'focussed' someone is on some task or other. I worked on a video game demonstration called "Neurostorm" that was shown at the Google I/O event a few years ago that awarded points in a video game depending on how mentally focussed you were as you shot at various targets. But those are very high level things, and we can only measure them with sensors that are actually touching your head. Even a few millimeters away, the signal we'd be measuring would be so insanely tiny that there is no way we could pick them up. The idea of measuring those things from across a room is quite impossible - and from orbit? Hell no - the laws of physics don't allow that! Another way to measure how you're thinking is to watch how much blood has to flow to each part of the brain as it works harder or relaxes. This kind of measurement can tell you things like whether someone is enjoying a piece of music or not, quite detailed stuff like that. But this requires that you stay very still inside a gigantic machine that fills a room. We still can't measure stuff like that from more than a couple of feet away. So I'm not saying that a computer can't "read your thoughts" - what I'm saying is that it can only do it through electrodes that are actually touching your head - or a gigantic machine that you're laying inside of. And I'm saying that all it can read is very high level stuff - it certainly can't pick up an individual thought. So what you're claiming is simply not credible. There is no technology, nor any reasonable possibility of technology that could tell what you're thinking from orbit. SteveBaker (talk) 15:09, 23 February 2015 (UTC) I'm not going to say, "You guys are wrong", I'll say, "Mechanisms exist and you guys are unaware of it". This mechanism is inevitable just like UFO. I thought you guys would know, surprised that you guys don't - probably because it is a government controlled product... People beside the government do possess this mechanism, its just hard to catch them as it is impossible to trace... -- (Angelos|Angelus (talk) 18:39, 23 February 2015 (UTC)) Yes, the Government. The same people who can't get their thumbs out of their asses long enough to write meaningful legislation to deal with ANY major problem facing society today; has somehow gotten their hands on a mind-control/telepathy device which they developed all on their own, with no help from independent academia, and which there are no published studies to show such a thing is even possible. Yet this Government of ours somehow has secretly sequestered a bunch of scientists to invent a device which absolutely no one anywhere else has even hinted might be possible to invent, and they did so. You do realize how batshit insane that sounds, right? --Jayron32 18:43, 23 February 2015 (UTC) Not to mention that if they were to have such a technology, it would be the ultimate weapon of war and social control, and they would long since have succumbed to the irresistible urge to use it as such: they wouldn't waste their time on using it merely to persecute individuals. The continued existence of dissent and conflict of every form, worldwide, is thus pretty good evidence for the non-existence of any mind-control technology. Update: I see you're already familiar with the concepts of ideas of reference and delusions of reference, so I won't belabour you with mentioning them again. -- The Anome (talk) 18:47, 23 February 2015 (UTC) Governments have, in the past, experimented with that sort of "mechanism" (and probably still do). Sometimes the military have money to spare and are easily fooled, though it might be fairer to say that they will try anything, however unlikely, on the remote possibility that it will give them an advantage. Like Angelos, I put such claims in the same category as UFOs (but we don't agree on what category this is). Dbfirs 19:04, 23 February 2015 (UTC) Absolutely: they've certainly tried to develop mind control technology (MKULTRA and Psychotronics, for example, both failures), and will no doubt go on trying to do so. But at the moment, the nearest we have to effective mind control technology is the mass media such as television. Which brings us full circle. -- The Anome (talk) 19:30, 23 February 2015 (UTC) There have been very interesting things done with terahertz radiation, e.g. determining which species of fungus infects a tree, or scanning for anthrax in the air. I would not be surprised if the bastards already have it optimized to detect specific genetic markers that can be used to identify individuals. Doing it from orbit would be hard, first because the atmosphere is opaque to some terahertz frequencies (it's a complicated looking absorption curve) and second because of the resolution and detection limits. More likely drones, I think. The use of terahertz or nearby frequencies to duplicate or improve upon putative Mobile phone radiation and health effects also cannot be ruled out. In theory, it shouldn't be able to break DNA, but persistent attack at specific frequencies might affect the binding of transcription factors or other gene enhancer regulators, potentially allowing the induction of effects like cancer, depression, mental illness etc. Wnt (talk) 20:58, 23 February 2015 (UTC) "Terahertz interferometry" via synthetic aperture radar, is the answer to OP's first question. The resolution is easily enough to identify individuals by shape of body parts and distinguishing features of personal effects and vehicles. The effective resolution for most materials is at milimeter-scale. 184.96.139.187 (talk) 01:18, 24 February 2015 (UTC) Long-baseline Terahertz interferometry from orbit would not be practical, due to the fact that the extreme levels of atmospheric absorption at those frequencies would make it impossible to use from a satellite. Even allowing for the fact that the atmosphere thins out as you go higher, 100 dB/km loss at 1 atm does not make for good seeing, particularly if you were attempting to use active radar, in which case you've got that level of loss both coming and going. Of course, those same losses also make terahertz radiation very attractive as a short range technology. See http://spectrum.ieee.org/aerospace/military/the-truth-about-terahertz for more background on this. -- The Anome (talk) 14:09, 24 February 2015 (UTC) Most of you are only talking about the government only, do not forget, government is not the only one, e.g., governments are not the only one's who is capable of making guns, people who hate the government and wish to possess such tools do make them for the sake of it, for possession, out of hatred, desire... Currently I can't provide any evidence, I'm doing a thorough research again, in time, when I do I'll insert the references, but for now some user's addressed a couple of names, though to note, 'television' and 'radio'/words is not comparable to the technologies they uphold now. The word 'failure' is used to cover the 'truth' up... You have to be naive to believe that government will fail in trying to do something, especially U.S.A and Russia. These are the only two countries concerned about future Wars. And people, society is not good, isn't that the reason why there is a government, legislation... -- (Angelos|Angelus (talk) 07:51, 24 February 2015 (UTC)) The key words in your comment above are "I can't provide any evidence". Can you tell us why you believe these things must exist, if you have neither evidence, nor a plausible mechanism for these things to be possible? -- The Anome (talk) I believe I can The Anome, funny thing is, you'll disbelieve it even after telling or showing; like the majority of people. Nothing is hidden from God; 'revenge of the fallen' after death... -- (Angelos|Angelus (talk) 19:05, 24 February 2015 (UTC)) Q: Friends, how would you classify the telepathy mechanism then? Since 'tele' means 'wave' technology products, and Dbfirs stated telepathy is not a technology? -- (Angelos|Angelus (talk) 07:56, 24 February 2015 (UTC)) That's simple. Without (a) evidence that telepathy exists, or (b) knowledge of any physical mechanism that would allow it to be possible, the default reasonable position is to assume it does not exist, unless further evidence comes to light that either (a) or (b) might be true. The same applies to unicorns, UFOs, and supernatural phenomena such as ghosts. Just because a name exists for some hypothetical thing (eg. "telepathy", "telekinesis", "ghost") does not mean the thing referenced by that term exists, and there is no need to explain it. At the same time, plausible evidence for either (a) or (b) in any of these cases should cause any reasonable person to reconsider their non-belief in those things, no matter how low their initial prior probability for it was. But the burden of proof is on the proposer to provide that evidence. -- The Anome (talk) 14:17, 24 February 2015 (UTC)

GR inertial reference frames.

This may be a stupid question. As I understand it in General Relativity the laws of physics hold true for all inertial reference frames. What about non-inertial reference frames? Can you take any arbitrary point declare that it is rotating and apply the the laws of physics just as well as at any other point? I ask because I'm in discussion with a geocentrist and the stuff they are saying is clearly wrong but I'm no physicist. — Preceding unsigned comment added by AHuntersMoon (talk • contribs) 19:43, 22 February 2015 (UTC)

In General Relativity the laws of physics hold true for an arbitrary reference frame. All reference frames are absolutely equal. Ruslik_Zero 20:58, 22 February 2015 (UTC)

This is really at a lower level than relativity, but "Yes" is the answer to your question - the laws of physics are applicable everywhere. The essential point is that an observer in a non-interial (accelerated) reference frame can detect that fact by measuring the acceleration. We can do that now by dropping something (see Isaac Newton#Apple incident) and using Foucault's pendulum or a gyroscope or a bathtub to measure the Coriolis effect. All of which are quite valid under Newtonian mechanics without relativity becoming involved. Tevildo (talk) 21:23, 22 February 2015 (UTC)

You're having a serious discussion with a geocentrist? Did you make a typo, or are you really trying to debate someone who thinks the whole universe revolves around the Earth? --Bowlhover (talk) 02:02, 23 February 2015 (UTC)

The equivelance of all frames in GR means that it is quite utterly meaningless to ascribe any point as being the center. Everything rotates about everything else, and if this geocentrist wishes to treat the center of the earth as the center of the universe, then that's a perfectly valid point to choose. Of course, picking the center of the milky way galaxy might make some calculations easier...but then choosing the driver's seat of his/her car would make a better choice for other calculations. It's all a matter of choosing an appropriate coordinate system for the task at hand. If you wish to avoid getting a speeding ticket, then choosing your car isn't going to help you when plead that your vehicle was stationary rather than doing 90mph in a 55 limit. On the other hand, if the judge chooses a heliocentric viewpoint then you're going to jail for driving at 30 kilometers per second. On the other hand, if you ask your passenger to hand you a mint from the glovebox, you'd prefer that he not try to figure out where to grab it from using a coordinate system based on the large continent on Kepler-22b.

Incidentally, if your opponent in such a debate is truly in need of a sound logical spanking, they are probably drawing poor conclusions from their core belief. I recommend asking how it can be that we have rovers driving around on the surface of Mars and how, from the rover's point of view, it would appear that Mars is the center of the universe. Sadly, such people are apt to deny the existence of Mars rovers, manned moon landings, safe measles vaccines, the holocaust and so forth.

If you really want to meet some people who are REALLY good at spinning a story around scientific improbability, just get chatting to some of the few remaining core members of the flat earth society. Their arguments are oddly compelling!

Good luck! SteveBaker (talk) 04:51, 23 February 2015 (UTC)

The origin of a coordinate system and the center of a physical system are different things. When people say that sun is at the center of the solar system they don't mean that the origin of coordinates should be there. They mean that the sun is at (or near) the barycenter of the solar system. It's a geometric property that has nothing to do with coordinate systems or any other arbitrary unphysical choice. In general relativity, spacetime has a definite geometry. You're not free to imagine that it has some other geometry. -- BenRG (talk) 08:41, 23 February 2015 (UTC)