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August 2

Will the recently found debris from missing airplane MH-370 help to locate the plane?

Let's just assume that the debris found near Réunion Island is, in fact, from the missing airplane MH-370. Does that conclusion in any way help searchers to actually find the plane (i.e., the rest of the plane)? If so, how so? Or does this discovery simply tell us three basic things: (1) Yes, it was MH-370; (2) Yes, it crashed; and (3) Yes, it crashed somewhere into the Indian Ocean. Other than that very basic info (those three facts that I listed), can this conclusion (that the debris is definitely MH-370) help locate the missing plane at all? Thanks. Joseph A. Spadaro (talk) 06:10, 2 August 2015 (UTC)

If examination of the recovered item proves that it came from MH-370 it won't help locate the flight data recorder or the remainder of the wreckage. However, close examination of the item may provide information as to whether the aircraft struck the ocean at very high speed, such as in a steep dive, or at the sort of speed appropriate to a controlled ditching. It may also reveal whether the item has been deeply submerged before breaking free from the wing and rising to the surface, or whether it broke free before the remainder of the wreckage sank. None of these things are likely to contribute to knowledge about where the aircraft struck the ocean but they might provide a little information that the world doesn't presently have. One thing is certain - this item will be subjected to the most intense scrutiny by a lot of people trying to find out whatever they can. Dolphin (t) 06:29, 2 August 2015 (UTC)

Can people who study waves, currents, and water paths somehow calculate a "reverse" path, to see where the debris originated? Joseph A. Spadaro (talk) 06:35, 2 August 2015 (UTC)

Yes they can back calculate likely paths, aided by a zillion little rubber ducks http://www.columbiatribune.com/editorial_archive/rubber-ducks-still-floating-after-years/article_1533a1a4-f9e8-11e2-afcf-10604b9f6eda.html . More to the point any relevant wreckage at all provides confidence that they are in the right hemisphere, and not completely wasting their (my) money. Greglocock (talk) 06:40, 2 August 2015 (UTC)

Here is the Wikipedia article on that event, with the Rubber Ducky Toys: Friendly Floatees. Joseph A. Spadaro (talk) 07:39, 2 August 2015 (UTC)

Yes. But there would be many such reverse paths; and the information wouldn't show whereabouts on any of those paths the item began its languid journey towards la Reunion Is. About all such information would reveal would be a statement that the item was almost certainly released somewhere in the Indian Ocean. Even that would be useful in dispelling some of the conspiracy theories about the aeroplane being flown to a secret destination in Asia or India or China etc. Dolphin (t) 06:44, 2 August 2015 (UTC)

On the news the other day, they were saying that studying the barnacles attached to it may help determine what depth it came from, as there are apparently different types of barnacles at different depths. The report also said that the current search area appears plausible as an area of origin. Rather large, of course. As to the conspiracy theories, that garbage most likely created false hope for the relatives of the missing. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:01, 2 August 2015 (UTC)

I'm not suggesting the discoveries will silence the purveyors of conspiracy theories! I imagine they will see the item discovered on the beach as incontrovertible proof that the bad guys fabricated a piece of a B777 wing, tethered it in the sea for a year to build up a few barnacles, and then deliberately placed it on a beach on la Reunion Island to mislead the world into thinking the aircraft splashed down in the Indian Ocean, and therefore stop looking at isolated airstrips in Asia, India, China etc! Dolphin (t) 08:05, 2 August 2015 (UTC)

The finding of MH-370 wreckage in the ocean can be summarized in one quote: "They're dead, Jim." --DHeyward (talk)

I think that this discovery will lead to some very productive work in modelling the ocean currents and debris field. Already a second piece of flotsam (though I am sorely tempted to call it jetsam) has been discovered on the island ( [1] ) Previous models predicted the wreckage would turn up 4500 miles away, at Indonesia [2]. That article also says the plane didn't nose-dive, but descended gradually or ditched. I feel like there are two possibilities - one, the models are wrong, or two, the search was in the wrong place all along. It will be interesting to find out which.

I've definitely been inclined to follow the conspiracy ideas, and really, the wreckage sort of backs them up. Initially, I thought the plane might have been hijacked and hidden somewhere, but as ransom demands never turned up, that seemed less likely, and then the search proposed it was taken south somewhere it couldn't reasonably be expected to land. But if the plane turns out to have gotten most of the way to Africa instead, this could be seen as the same hijacking plan, but simply running out of fuel along the way. Wnt (talk) 11:12, 2 August 2015 (UTC)

Your link about a second piece doesn't provide anything useful but AFAIK, there have been no other pieces found which so far where there's any real confidence they may be from MH370.

There was a piece of what appears to be a suitcase or other such container which was found near the flaperon, but it had no barnacles. It's been taken for investigation but it's such a small portion and appears tattered and damaged enough that it would seem likely even if the investigators have high resolution photos of the every pieces of lugggage from all angles (which they don't), it would be difficult to reliably conclude it came from MH370.

There was a Chinese water bottle and a Indonesian cleaning product bottle, who's linkage seems to me to me a major case of WTF?

Some people have suggested they burnt what appeared to be a seat, from a plane, hang glider or something else a few months ago. Not quite as bad as the water bottle and cleaning product bottle but, still since it's been destroyed it's fairly useless and there's a good chance it is completely unrelated. The same person said they found luggage which was full and similarly burnt. This seems more odd (the fact that it was full I mean as it's not something people normally just throw away if it was full of normal luggage stuff although unless it was opened it could have been full of rubbish), but it's also useless now and there's also a very good chance it's unrelated.

There was the part initially described as a door, but is now suggested to be part of a ladder, and photos have emerged it was little more than a twisted chunk of metal [3]. (It also appearantly had Chinese writing on it which I think is unlikely on the door of a Malaysian Airlines plane, even one which was on a route to China.)

There has also been suggestion of some mysterious water bottle given to pilots to keep them awake. No idea what this is but while it is a little more unusual than some random water bottle, it's likewise difficult to reliably connect it. [4]

The only conclusion we can make from any of the supposed debris is that it's not a good idea to assume every single piece of rubbish which came from one of the world's major rubbish dumps on to an island in the middle of said rubbish dump which has several people who's (only?) job is to go around picking up said rubbish; is from MH370. And also, now that a piece which almost definitely is from MH370 was found there, you're almost definitelyunsurprisignly going to get that from the media and people on the island.

Nil Einne (talk) 15:07, 2 August 2015 (UTC)

BTW, on another point your link itself says the plane descending gradually was what's been predicted for a very long time.

As for the ocean modelling thing, your link suggests the confidence in these predictions was always unclear. It's not that hard to find other discussions from before this finding such as [5] which actually do have other predictions (Western Australia), and more importantly suggest every more clearly there were always great uncertainties.

Perhaps most importantly, from what I've read most experts who have looked in to it, including the Australians you refer to, seem to agree that while the find may have been a bit unexpected, it doesn't actually suggest the search area was wrong. See e.g. [6]. So either these experts who you're relying for your conspiracy theories have all decided to get in on the conspiracy. Or they didn't and you have to also trust them when they say there's nothing in the latest finding which suggests the current predicted crash location is wrong.

Nil Einne (talk) 15:07, 2 August 2015 (UTC)

I should clarify that I'm not suggestion efforts shouldn't be made to identify and attempt to determine if stuff found may be from MH370, simply that it's a mistake to trust media reports about possible pieces being found since in reality probably something like 99% or even 99.9% of reports are going to be false positives at the moment. It's definitely sounding like whatever Wnt refered to above was one. Nil Einne (talk) 19:29, 3 August 2015 (UTC)

I heard these suggestions from an aviation expert on the news:

1) Since the item is intact, that suggests the plane did not crash at high speeds.

2) The outside edge of the control surface shows wear of the type expected when rapidly hitting the water, but not the rest of the flaperon. That points to it landing in the water with the flaperon down, presumably in an attempt to lose speed and survive the landing. This all suggests a pilot trying to land safely.

3) However, the flaperon being separated from the wing implies that the landing was not successful, and the plane broke up. But, if it crashed at low enough of a speed, there might have been survivors. If so, the lack of bodies suggests they either didn't survive for long, or, more ominously, were picked up and hidden away.

As for my own thoughts, I suspect a conspiracy to kidnap a planeload of people and ransom them back. There would have been a boat there to pick them up, but apparently the landing was botched and everyone died, so no ransom demands were ever sent. I'd look into any boats in the area at the time, even those with a valid reason, like fishing boats. StuRat (talk) 23:33, 2 August 2015 (UTC)

WP:NOTFORUM. AndyTheGrump (talk) 23:55, 2 August 2015 (UTC)

Thanks, all. Joseph A. Spadaro (talk) 04:02, 4 August 2015 (UTC)

Knee anatomy

There is a large cord I can see and feel on the lateral (outside) part of the knee and I'm curious what part of the knee it is. Here is a picture http://i58.tinypic.com/2j1sksz.jpg I am thinking either the LCL, the IT band, or the hamstring.--Tarhound21 (talk) 07:47, 2 August 2015 (UTC)

See Knee. That is indeed the fibular collateral ligament - the hamstring is positioned more medially (down the centre of the knee at the back, not at the side). Tevildo (talk) 08:17, 2 August 2015 (UTC)

No.

From the picture it looks as if the OP has the tip of his index finger on the common (long and short head) tendon of biceps femoris, which is part of the hamstrings. The OP can confirm this by palpating the tendon while attempting to further flex the knee (by contracting the hamstring) while trying to rotate the lower leg (as indicated by the front part of the foot) towards the outside (= external rotation of the lower leg and foot), while the knee remains in the position as photographed. If the knee does not flex or rotate (by keeping the foot firm on the ground and not moving the body or upper leg) only tendons that are attached to muscles would tighten, while a (passive) "tendon only" cross-joint tendon would not alter its tension or orientation.

The fibular collateral ligament (FCL) runs between the the lateral epicodyle of the femur and the fibula. The lateral epicondyle would be 4 to 5 cm "anterior" - approximately in the 12 o'clock position - relative to the fingertip on the picture. If one palpates between that bony point and the top of the fibula (where biceps femoris also inserts) one will feel a ridge that is the FCL. In the position illustrated in the picture, the FCL would be orientated vertically down towards the floor.

The hamstrings are not "down the centre of the knee at the back", they form the lateral (outside) and medial (inside) borders of the popliteal fossa behind the knee. Christom — Preceding undated comment added 17:20, 2 August 2015 (UTC)

How do mammals that live in seawater avoid dehydration?

So as not to end up as humans would as explained here? 75.75.42.89 (talk) 19:32, 2 August 2015 (UTC)

They can excrete excess salt more efficiently than humans. Ruslik_Zero 19:49, 2 August 2015 (UTC)

What you seem to be asking is what do strictly-seagoing mammals use as their water source. Googling the subject ("where do [mammal name here] get their water?" indicates that they ingest seawater to some extent, but that much of their water comes from fish they consume. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:51, 2 August 2015 (UTC)

Don't mean to bite, but this seems like an exceedingly easy question to google. The very first result seems to have all the answers. Vespine (talk) 22:59, 2 August 2015 (UTC)

They excrete the excess salt. Okay, that's kind of the obvious answer. From the evolutionary perspective, doing so requires actively transporting the ions against the concentration gradient (seawater is saltier than the animal's body), which requires energy. This means less energy available to the animal for other purposes. For animals living in saltwater, this is just an unavoidable cost of maintaining homeostasis. But on land, and in freshwater, the problem is the opposite: it's difficult to get enough salts in your diet. The body has to limit how much is excreted. Since the ability to concentrate and excrete excess salt is no longer necessary, there's a strong selective pressure against it, to free up the resources that would be invested in such a trait. In the case of marine mammals, they evolved from land-dwelling mammal ancestors and then re-adapted to living in a marine environment. There are many signs of this, such as the fact that their flippers and fins are modified arms/hands and legs/feet, complete with little vestigal foot bones in whales. This kind of thing, when species that aren't closely related but live in similar environments develop similar traits, is called convergent evolution. --108.38.204.15 (talk) 02:38, 3 August 2015 (UTC)

Turner syndrome

I have a niece with this condition and one symptom was her large bulbous neck at birth. Yesterday I was talking to a friend and she mentioned her son had this funny (large bulbous?) neck at birth. On reading the article about Turners, is this only females that get this syndrome? Can extra skin around the neck at birth mean anything else? 203.97.202.181 (talk) 21:32, 2 August 2015 (UTC)

The article says it's females only, due to a missing X-chromosome. Assuming the article is correct, your friend's son must have some other condition. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:38, 2 August 2015 (UTC)

We have an article on "webbed neck" that lists some other causes besides Turner syndrome, but we cannot diagnose what (if anything) is present in a particular person. Wnt (talk) 03:16, 3 August 2015 (UTC)

It's absolutely possible for a son to have Turner's syndrome if there is also mosaicism. A karyotype of 46,XY/45,X would result in a child with Turner's syndrome, and, depending on where in the body the 45 X cells are, the child could be either a boy or girl. See [7]. There is also this review of postnatally diagnosed cases of 45,X/46,XY mosaicism in which 3 males considered normal at birth later developed signs of Turner's syndrome. It's quite rare, and I suspect that our article is oversimplifying in an effort to keep things simple. - Nunh-huh 23:54, 3 August 2015 (UTC)

August 3

Locating the geographic poles of the Earth

How explorers, especially the early expeditions, located the poles of the Earth? You have seen those photos of people, flagpoles, tents etc. at North Pole and South Pole; how did they know that they where at the right place? --Sivullinen (talk) 01:48, 3 August 2015 (UTC)

Robert Peary#Controversy actually has some interesting discussion of how reaching a pole was supposed to be "proven" at the time; also if you follow references from that article, you can learn more. --Jayron32 02:02, 3 August 2015 (UTC)

Assuming you mean the axis of spin of the earth, then a theodolite or sextant and the stars would do it. When the stars directly overhead are motionless you are at the pole.Greglocock (talk) 02:06, 3 August 2015 (UTC)

Since the explorers were traveling in the perpetual daylight of summer, they used observations of the sun rather than the stars. You can read about Amundsen's procedure in the article Polheim. He used a sextant because his theodolite was broken, and took pains to "box" the South Pole so that at lest one of his expedition members would definitely have passed very close to the geographic pole. Scott's party seems to have used a theodolite, shown here in use [8]. Although Scott found Amundsen's tent and letter at the South Pole, of course he wanted to make his own observations rather than trusting that Amundsen got it right. The principle is that when you're exactly at the Pole, the sun goes around in a day at almost constant elevation. If you're a little away from the Pole, the sun will appear to dip a little in one direction and rise a little in the opposite direction. --Amble (talk) 02:47, 3 August 2015 (UTC)

Of course, there's also the problem that the actual poles themselves move around. That is, the exact axis of rotation of the Earth does not intersect the solid Earth at the same point all the time. See Polar motion, Chandler wobble, etc. --Jayron32 02:50, 3 August 2015 (UTC)

That's true, but those effects are too small to be relevant to Heroic Age explorers planting flags. --Amble (talk) 03:50, 3 August 2015 (UTC)

It might be dificult to say the exact spot but relatively easy to know when it was crossed. Miles in either direction, as long as it was crossed, would be good enough to claim being there. --DHeyward (talk) 05:46, 3 August 2015 (UTC)

Robert Falcon Scott and Amundsen must have both used the same highly accurate method, since Scott found Amundsen's marker flag planted five weeks earlier in the middle of a vast continent. Alansplodge (talk) 16:38, 4 August 2015 (UTC)

The method of looking at sun or stars to determine when you're at the pole gives you one definition of the pole. Using a compass reveals when you're at the magnetic pole. At the magnetic pole, a compass held on it's side will point straight up and down. Some polar explorers used compasses specifically designed to make this measurement. The magnetic poles also move over time - so this is also an inexact process.

SteveBaker (talk) 17:27, 3 August 2015 (UTC)

Magnetic poles are located thousands of kilometers away from the geographic poles and are not very relevant to the question. --Sivullinen (talk) 20:26, 3 August 2015 (UTC)

You didn't specify which kind of pole you were talking about in the question - so my response was entirely relevant right up to the time you said it wasn't! :-) SteveBaker (talk) 01:04, 4 August 2015 (UTC)

Except he did specify, in the original heading. --Amble (talk) 02:00, 4 August 2015 (UTC)

What's inside the hip?

A relative just dislocated his replaced-three-months-ago hip joint and had to have surgery this evening to put it back in place, and I was in the waiting room to hear the surgeon discuss the results after they were done. One of his reasons for saying that all had gone well was that he'd barely had to cut anything: he just made an incision in the skin and took away a little soft tissue, but everything else required no cutting. What's the hip region made of, and how can one get to the bone without cutting anything significant? I assumed that the surgeon would have to cut some muscles in order to get access to the hip joint, but that's obviously not the case. Beyond the hip article, I don't know where to look; I found articles such as Capsule of hip joint, but my knowledge is so weak that I don't even understand what the capsule of hip joint is, for example. Nyttend (talk) 02:23, 3 August 2015 (UTC)

Arthroscopy was invented almost 100 years ago, and has been industry standard for 30+ years. Many (perhaps even most) surgeries nowadays require much smaller incisions than the non-surgeon would imagine they would. --Jayron32 02:47, 3 August 2015 (UTC)

I'm confused. The relative had his leg badly out of joint, and the arthroscopy article seems to suggest (unless I misunderstand) that it's for looking around and making minor repairs, not for moving major bones that are badly out of joint. Nyttend (talk) 02:59, 3 August 2015 (UTC)

Unconfuse yourself. --Jayron32 03:02, 3 August 2015 (UTC)

You posted that while I was looking through the Hip arthroscopy article. Is this kind of stuff already in the article, or could it be added? I'm not sure where it would belong. But thanks for finding the AAOS article; it's nice and unambiguous, and quite helpful. Nyttend (talk) 03:04, 3 August 2015 (UTC)

I'm no doctor, but I believe muscles are never cut in surgery unless absolutely necessary. Muscle cuts and tears are very painful, take a long time to heal, and impair use of the muscle during healing. If you need to get access to things under muscle, you just spread the muscles apart and keep them there with retractors and other fun tools. Skeletal muscles are divided into, well, different muscles. They're discrete bundles of muscle fibers, wrapped in fascia. Part of learning to be a surgeon involves memorizing all of them and their locations. You don't have one continuous sheet of muscle under your skin. For certain surgeries, such as abdominal surgeries, they actually paralyze you with neuromuscular-blocking drugs to stop your muscles from contracting during the procedure so they will stay put. This requires mechanical ventilation, as it paralyzes the diaphragm. --108.38.204.15 (talk) 03:05, 3 August 2015 (UTC)

I would think that anything that physically must be torn in order for the hip joint to be pulled apart and moved to where it is must already have been torn in the accident, so in theory, provided the muscles can be relaxed, any debris cleared and the joint manipulated with enough control, it should be able to fit back along the same path it came out through. Wnt (talk) 03:36, 3 August 2015 (UTC)

Impossibility fallacy

By my bad luck or by some other cause, I have many times seen and heard people dismissing ideas or designs on the basis that "if this could be done this would have been done already", or "this has not been done, therefore this can not be done". What is the name of this fallacy? I have read our list of fallacies but I haven't found a close enough match. Did I miss it? What's the proper name of this fallacy? Thanks in advance, Dr Dima (talk) 04:52, 3 August 2015 (UTC)

Max Beerbohm came close to this when he said: Anything that is worth doing has been done frequently. Things hitherto undone should be given, I suspect, a wide berth. -- Jack of Oz ^{[pleasantries]} 05:56, 3 August 2015 (UTC)

It's perfectly rational to have less confidence in a claimed discovery if it's something that would likely have been discovered earlier if it were true. -- BenRG (talk) 06:17, 3 August 2015 (UTC)

(It's also rational to put less trust in someone's claims on learning that they're a politician, even though that's called "argumentum ad hominem", and to be more trusting of a physicist's claims about physics than a non-physicist's, even though that's called "appeal to authority". So it is still possible that the hasn't-been-done-before argument appears on lists of fallacies under some name, since they are bogus anyway. Someone should come up with a nice Latin name for the belief that it's wrong to pursue a line of argument that appears on these lists.) -- BenRG (talk) 07:18, 3 August 2015 (UTC)

We do have it. Faulty generalization is the term. It is most likely true of a sample that most inventions fail uniqueness. Yet we know the population has invention. That the sample doesn't reflect the population is a truism in statistics. Or perhaps more understandably, the population of all things exceeds the sample of known inventions. It is a "faulty generalization" to claim all things is bound by all known things. --DHeyward (talk) 06:53, 3 August 2015 (UTC)

Is there actually anyone who believes that claims of new discoveries are false because nothing remains to be discovered? I think "an extraordinary claim requires extraordinary proof" is closer to what people mean when they say "this has not been done, therefore this can not be done". If you produce the unicorn you claim to have caught and it passes all their tests, then they'll believe you, but not before. This saying doesn't appear on lists of fallacies, but that's fine because it isn't a fallacy. -- BenRG (talk) 07:18, 3 August 2015 (UTC)

Agree, but if people mean it literally, then it is a logical fallacy. Supdiop (Talk🔹Contribs) 08:13, 3 August 2015 (UTC)

• It is not always a fallacy, because the reasoning can be valid if certain extra premises are added. When it is a fallacy, formally it is the fallacy of the undistributed middle. Looie496 (talk) 12:47, 3 August 2015 (UTC)

• Yes, if it is something seemingly obvious, then you would expect that somebody would have tried it before. For example, if you could pour saltwater into a normal car engine and get it to run, somebody would have figured that out by now. On the other hand, there might be some new technology which could find a way to extract energy from saltwater (I'm not saying there is, just that we can't discount the possibility because it hasn't been done before). StuRat (talk) 16:17, 3 August 2015 (UTC)

And there is: osmotic power. Of course it wouldn't be useful for powering a vehicle, since the energy density is really low, and it requires expensive and fragile equipment. --108.38.204.15 (talk) 22:30, 3 August 2015 (UTC)

This is really a matter of probability and perhaps of Occam's razor. Without additional information of some kind, if you are unsure of whether something could be done, and it hasn't - the odds are much higher that it can't be done than that it can. It's not certain though - so this is a statement that should be modified by the word "probably"..."If this were possible, it would probably have been done already". Occam's razor might also apply here - that's another tool of inexactitude that never the less proves useful. StuRat's example of running a car on water is a great example of that. It hasn't been done - and the laws of physics strongly suggest that it can't ever be done *BUT* there may be laws of physics of which we're currently unaware that might make it possible. Occam's razor says that the simplest explanations are the best - and it's certainly simpler to assume that water-fuelled cars are impossible (because physics forbids them) than it is to assume that they'll eventually be possible (because we'll discover new laws of physics to make it so).

SteveBaker (talk) 17:21, 3 August 2015 (UTC)

• See also cui bono. If something does happen, it should be obvious that people benefit. There also the point that psychics never make a killing on the stock market, and that Miss Cleo didn't predict her own demise. That doesn't mean that people don't discover new useful things, like evolution, the germ theory of disease, or mechanical flight, although understanding such things had been declared impossible, or outside the realm of science. We even know how to turn lead into gold. μηδείς (talk) 21:07, 3 August 2015 (UTC)

I think some people are having difficulty understanding what a fallacy is. A fallacy isn't at all necessarily FALSE. A logical fallacy is a form of a non sequitur, the conclusion does not logically follow from the premise. "Lots of people think the world is round, therefore the world is round", this is a logically fallacious argument, even though the premise AND the conclusion are both true. An argument can't be logically fallacious some times and not at other times, it either is or isn't. "The preeminent expert on geology says the world is round, therefore the world is round". This might indeed even be an extremely good reason to believe that the world is round, but it's still a fallacious argument. Vespine (talk) 23:28, 3 August 2015 (UTC)

That's an Argument from authority, fallacious because the preeminent expert can still be wrong. However, it makes sense as an inductive argument: "The preeminent expert on geology says the world is round, therefore the world is probably round". Nyttend (talk) 17:58, 4 August 2015 (UTC)

That's exactly the point I was making :) One of the 1st replies was It's perfectly rational to have less confidence in a claimed discovery . Just like it's perfectly rational to "believe" the world expert on something, but that has nothing to do with logical fallacies. Come to think of it, I think rational is actually the wrong word here, I think it should have been reasaonable. It's perfectly reasonable to have less confidence, it's not perfectly rational. Vespine (talk) 22:52, 4 August 2015 (UTC)

This is something of a variation on the old saw "Absence of evidence is not evidence of absence", which is touched on as a sort of informal fallacy in argument from ignorance. That said, some other comments above have gotten to the edges of the problem (which is at least partly semantic). Eliezer Yudkowsky covers it well here in his blog. Essentially, while absence of evidence is not conclusive proof of absence, the absence of evidence is at least weak evidence of absence. TenOfAllTrades(talk) 03:22, 5 August 2015 (UTC)

Why do illness symptoms vary so much

Why is it that the same infection can cause different symptoms in different people or even different symptoms on the same person if they get it more than once? For example, a stomach bug can cause vomiting in some people, diarrhoea in others, both in some, and neither in a few. Why? — Preceding unsigned comment added by 94.14.228.44 (talk) 09:49, 3 August 2015 (UTC)

Symptoms are results, sometimes suffer. It is a good job done to find the cause. Other diseases for example multiple sclerosis is also known as "the disease of the thousand faces" due the variety of symptoms. --Hans Haase (有问题吗) 12:37, 3 August 2015 (UTC)

Probably the biggest factor is where the microbes develop. For example, some microbes can survive in the digestive tract, if you consume food containing them, or in the lungs, if you inhale them. For example, per plague (disease): "The symptoms of plague depend on the concentrated areas of infection in each person: bubonic plague in lymph nodes, septicemic plague in blood vessels, pneumonic plague in lungs, and so on". StuRat (talk) 15:57, 3 August 2015 (UTC)

Immune response and tolerance can vary greatly from person to person. For example, there are people that are naturally tolerant to even the latest strains of Hospital acquired MRSA while others will develop infections that cause death. It keeps the oral-fecal transmission route alive as there are still living carriers. Montezuma's revenge is another one demonstrating that regional flora are different and the populations have adapted to them. There are very few "bugs" (virus or bacteria) that kill everyone and it seems the reactions are also across the spectrum (from severe to mild to none). This recent article describes how a carrier with no symptoms, likely contaminated an endoscope with a very nasty bacteria that survives the cleaning procedure. Unfortunate for the next patients but they don't know exactly who brought it in and likely simply lived with it, unknowing. It also makes tracing difficult. Also, a person might react differently to even very minor changes in the bacteria or virus. It also varies with age and health so an infection at 20 isn't the same as an infection at 80. Another way to look at it is, prior to anti-biotics and immunizations, we still survived (albeit with poor outcomes likely in at-risk people). Polio, for example, is tolerated except for a percentage where it causes death or paralysis. We have a spectrum of outcomes for virtually every bug and that appears to be built into our natural variation. --DHeyward (talk) 19:13, 3 August 2015 (UTC)

See the Asymptomatic carrier article; Typhoid Mary was a prominent example of one. Nyttend (talk) 15:11, 4 August 2015 (UTC)

Head tattoo

What are the effects of a permanent and a temporary tattoo on scalp (especially the top part)? Can hair grow normally on it afterwards ? — Preceding unsigned comment added by 103.15.60.58 (talk) 10:44, 3 August 2015 (UTC)

Hair can grow normally over a tattoo. Causes interesting surprises when kids go into boot camp and get their head shaved. 209.149.113.45 (talk) 11:53, 3 August 2015 (UTC)

Hair regrown over a scalp tattoo has occasionally figured in supposedly historical stories as a means to send confidential messages (though I can't remember any specific instances). The device was also used in the W. E. Johns novel Biggles Buries the Hatchet, whereby an old acquaintance in a Soviet gulag alerts Biggles to his incarceration by a cryptic message and map tattooed on to the scalp of a fellow prisoner (illiterate, non-Anglophone and possibly mute – it's been a while since I read it) due for release. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 13:28, 3 August 2015 (UTC)

The tattoo method is mentioned in Steganography#Physical, with a link to Histiaeus, who was said by Herodotus to have used it. AndrewWTaylor (talk) 15:34, 3 August 2015 (UTC)

Funny that the obvious need to dispose of the slave afterwards isn't listed as an obvious drawback, but I guess they were pretty cheap for people of that station... Wnt (talk) 15:44, 4 August 2015 (UTC)

DNA lipofection complexes in suspension called an "emulsion"?

If DNA in solution is mixed with a lipofection reagent, in the resulting suspension correctly called an emulsion? --192.41.131.251 (talk) 12:46, 3 August 2015 (UTC)

This seems like a largely semantic question; someone might insist on a difference between a microemulsion and a "true" emulsion, for example. Nonetheless, if you are mixing phases in some fairly routine physical way (e.g. sonication), I'm thinking that ought to count as a true emulsion, no matter how complicated the structure that a manufacturer might potentially be striving to achieve with it using some well-chosen composition. The problem is, that's more an opinion than an answer, I'm afraid. It doesn't seem like an uncommon description, though. Wnt (talk) 15:38, 4 August 2015 (UTC)

Density of solids at extreme pressures

Can someone point me to a graph or equation that describes what happens to the density of solids at extreme pressures? (The density of a solid is pretty constant at normal pressures but what about cases like the density of iron at the pressure of the center of the Earth?) RJFJR (talk) 20:53, 3 August 2015 (UTC)

The Center for Rock Abuse is probably the preeminent experimental rock-crushing laboratory in the United States; they reside in the Petroleum Engineering department at Colorado School of Mines. Here's a list of their research publications. If you're interested in more observational science, Earthquake and Volcano Deformation is a good book on solid mechanics as it pertains to the massive stresses, strains, and pressures of geological processes.

If what you really seek is details about iron in the center of the earth, the models are much more diverse and a lot harder to validate empirically: you can find lots of references in our article on the inner core. Almost everything we know about this region is deduced from teleseismic soundings of earthquakes: the density can be inferred by estimating the speed of sound at which earthquake P-waves propagate.

Nimur (talk) 21:24, 3 August 2015 (UTC)

August 4

Huge southwest French spider?

This is as vague as it gets, but as far as I can tell from Googling around, everyone in France seems to think their spiders are small and relatively harmless. I was staying in a country house in the Gers department (southwest France, north of Pyrenees) and came upon an old well that had been hidden by overgrowth of vines and trees. Looking for (cautious) adventure, I dove into the jungly leaves and found the well to be sealed up by a wooden "house" structure on top of it, which had a wooden frame door. I opened this door up slowly with the intention of looking down and clinging to the inside of that door was the largest spider I've ever seen in my life, and I live in the western US (wolf spider is otherwise the largest I've seen, about the size of the palm of my hand). This spider looked like a massive orb spider, with legs spread to the size of a tight fist, the dark bulbous thorax being nastily large as well, completely brown, very heavy looking, and it was probably wondering what just happened to its glorious, dark domain. Any ideas what spider this may be? Really scary fella, not "small" by any means. Reflectionsinglass (talk) 09:43, 4 August 2015 (UTC)

I doubt that we have enough information for a positive ID, but does Lycosa narbonensis look familiar? It's found in that area. Deor (talk) 11:54, 4 August 2015 (UTC)

Ooh, nasty! I did take a photo of the spider but it's not a good one and currently stored away on some ex. drive. I will take your suggestion and compare it when I can. I seem to recall the spider being thinner (but just as bulbous in the back), and more evil looking, like something from a children's halloween book, but this is a great starting point. Thank you! Will return with more info when I can. Reflectionsinglass (talk) 17:56, 4 August 2015 (UTC)

Another possibility is Hogna radiata, also found in the south of France. Deor (talk) 20:41, 4 August 2015 (UTC)

Contemporary Technologies and the Brain

Assuming I'm concentrated in some word, can contemporary technologies identify this word? What's the probability to identify it correctly? Does it limited to some small and closed vocabulary that contemporary technologies can identify, or they can identify any word? 5.29.9.245 (talk) 13:10, 4 August 2015 (UTC)

No. A thought is a very complicated... ummm... thing. See also Brain–computer_interface. 196.213.35.146 (talk) 13:26, 4 August 2015 (UTC)

You may find this interesting: http://www.dailymail.co.uk/sciencetech/article-2814896/The-mindreading-machine-listen-voices-head-let-paralysed-speak-again.html 196.213.35.146 (talk) 13:38, 4 August 2015 (UTC)

Does winter gasoline have higher specific energy?

In the US, winter gasoline and summer gasoline have different compositions [9]. Does this difference in composition lead to a non-negligible difference in specific energy? The article already means winter gas being cheaper, so if its specific energy is higher too then that would be a double whammy. My other car is a cadr (talk) 13:18, 4 August 2015 (UTC)

According to our gasoline article, "gasoline blends differ, and therefore actual energy content varies according to the season and producer by up to 4% more or less than the average, according to the US EPA." So yes, there might be a difference, but probably not enough to matter very much. Looie496 (talk) 13:35, 4 August 2015 (UTC)

I think I understand what specific energy is, but I'm not sure; hopefully the rest of my response answers your question. When living in Indiana 2010-2014, I noticed that I typically needed to fill my gas tank after about 400 miles of highway driving in the summer and after about 320 miles of highway driving in the winter, even though I was driving in the same manner on the same roads. I got the same results all over Indiana and surrounding states, and any time I've discussed this with other Americans (regardless of the state), they've observed the same thing: winter gas doesn't have as much energy as summer gas. Nyttend (talk) 15:06, 4 August 2015 (UTC)

Additional reading suggests that there is more butane in winter gasoline than summer gasoline (see [10] [11]). That said, there are other factors that might affect gas mileage maybe? (heat vs. AC, road conditions that affect average speed?) shoy (reactions) 18:35, 4 August 2015 (UTC)

The article on Gasoline talks about energy per volume and energy per mass as if they are always proportional, but they are not. Gasoline is said to have a thermal expansion coefficient such that its volume decreases .00095 for a 1 C temperature drop. So if the winter temp is 55 C lower than the summer temp, as might occur in the midwestern USA, then the volume of say 20 gallons of gas would be smaller by .00095*55 or about 5%. Butif the same number of moles and the same mass of fuel is there, It would have the same "specific energy," or energy per mass, but a greater "energy density," or energy per volume, if you had the same chemical mixture of hydrocarbons but at a lower temperature. Edison (talk) 19:37, 4 August 2015 (UTC)

I've always thought of the idea that the "specific energy" of gasoline changes a lot based on temperature (eg, the idea that you should buy gas early in the morning because it's colder, and therefore you get more for your money) as somewhat of a myth. Do substances change density based on temperature? Sure. But you're buying gasoline that's been sitting in tanks underground, where the temperature is pretty constant. Also I don't know if you got your Fs and Cs confused above, but there's definitely not a 55 C difference between summer and winter temperatures (that would be 131 F). shoy (reactions) 17:56, 5 August 2015 (UTC)

There are several reasons as to why mileage would be lower in winter than summer, here and here for example. I've noticed that some people forget how long they let the vehicle idle to warm it up in cold temperatures, in this case anything below −20 °C (−4 °F). CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:40, 6 August 2015 (UTC)

Grumman LLV

The Grumman LLV gets 10 miles per gallon in normal use, and going by the standards typically applied to US road vehicles, it gets 18 miles per gallon if, for some bizarre reason, it gets driven on the highway. Why is the fuel efficiency so low? My old Chrysler Cirrus LXI got up to 30 on the highway, and my little Hyundai Accent can get up to 45 on the highway, even though the Cirrus was bigger than the LLV and the Accent's vaguely the same size. Nyttend (talk) 15:04, 4 August 2015 (UTC)

The rated EPA city mileage is actually 16 mpg; the actual in-service average of 10 mpg is the result of mail-truck driving conditions being substantially less fuel-friendly than the EPA test cycle. (Mail delivery necessitates carrying lots of cargo, with very frequent stops and starts above and beyond the usual city stop-and-go.) The three-speed automatic transmission won't help fuel economy or acceleration, either, and likely isn't geared for efficient highway cruising. And everything is built on a thirty-year-old framework optimized for lifespan rather than performance.

In contrast, the Hyundai Accent is about 600 pounds lighter (2100 lbs versus 2700 lbs for the LLV)—before you add in a quarter ton of parcels and mail sacks. It has a four-speed transmission (five if you get the manual gearbox) which probably includes at least one overdrive gear for better highway mileage. And the Accent is aerodynamically superior, what with actually having curved surfaces. The LLV is about as streamlined as a lunchbox. TenOfAllTrades(talk) 16:27, 4 August 2015 (UTC)

Stanene's room temperature super ? conductivity

I saw a recent news article [12] citing theoretical work on stanene ( [13] ) that says that the material might be "able to conduct electricity without generating any waste heat" because "electrons should be able to travel along the edges of the mesh without colliding with other electrons and atoms as they do in most materials." Specifically, "Stanene is predicted to be an example of a topological insulator, in which charge carriers (such as electrons) cannot travel through a material’s centre but can move freely along its edge, with their direction of travel dependent on whether their spin — a quantum property — points ‘up’ or ‘down’. Electric current is not dissipated because most impurities do not affect the spin and cannot slow the electrons..."

This is one of those cases where I might have a better chance with both hands and a flashlight.

• How does being a topological insulator lead to loss-free conduction?

• What is spin-orbital coupling or spin-momentum locking and why does it happen?

• Is there some relationship or analogy between the separated bands in this material and the Cooper pairs in a superconductor?

• Is this thing in any sense a superconductor, or are there things that don't have resistance that aren't superconductors?

• Why doesn't the magnetic field of the separated currents disrupt the predicted band structure? Or does it, with some kind of current limit appearing as in superconductors?

• Any other explication you can think of! Is this as cool as they say, if the predictions bear out?

Wnt (talk) 15:29, 4 August 2015 (UTC)

We do have a spin-orbit coupling article. DMacks (talk) 19:47, 4 August 2015 (UTC)

• The theoretical difference between a perfect conductor and a superconductor is that a superconductor is a separate state of matter, and is produced by quantum physical effects (electrons can be bound together into Cooper pairs through interactions with phonons). Perfect conductors and superconductors have in common the fact that if you expose them to a magnetic field, the currents this produces in the material exactly cancel out the magnetic field. However, if you expose a theoretical perfect conductor (i.e. one that obeys Maxwell's laws but doesn't have any weird quantum additions) to a magnetic field while creating it, you could "trap" the field inside it - the currents inside the material keep turning forever and sustain the field. Superconductors on the other hand under go a state transition which causes something called the "Meissner effect" – the expulsion of all fields inside the material - which can't be explained by Maxwell's equations alone. Superconductors aren't totally understood, but the model that describes them is BCS theory. I don't know whether stanene would display the Meissner effect or not, but its behavior is certainly due to quantum effects. Smurrayinchester 12:49, 5 August 2015 (UTC)

Maybe Nikola Tesla wasn't crazy after all ?

Tesla famously had the idea of broadcasting power rather than running wires. That failed to take off because so much of the energy is wasted and there's no way to (financially) charge those who receive it. There would also be a fair amount of danger from that much electricity broadcast through the air, in that anything which acts as an antenna might burst into flames.

However, did he ever consider narrow-beam transmissions of power ? Some possible applications:

1) Vacuum cleaner. The broadcast unit could be at the nearest outlet, and receiver on the vacuum cleaner. I picture parabolic antennae on both that track each other.

2) Lawn mower. The broadcast unit could be wired underground to the middle of the yard. Again, they would track each other. Advantages over gas lawn mower include being quieter and not polluting the air. Advantages over corded electric lawn mowers include no risk of cutting the cord. Advantages over battery-powered lawn mower include no batteries to recharge and replace when they won't hold a charge any more, and no time limit on each usage.

So, is this practical ? Would it be dangerous ? Has it been attempted ? Do we have an article ? StuRat (talk) 17:01, 4 August 2015 (UTC)

There are two questions that are only vaguely related. The first is whether Nikola Tesla was crazy. The second is whether his idea about wireless power was crazy. Just being crazy doesn't mean that your ideas are wrong. Just being sane doesn't mean that your ideas are right. Nikola Tesla was never diagnosed as psychotic, but it is clear that he had some sort of mental illness that some think may have been paranoid schizophrenia. John Forbes Nash was diagnosed as paranoid schizophrenic, but Nash equilibrium is accepted by the scholarly community. Thomas Edison was sane, and a shrewd businessman. However, Tesla was right about the feasibility of alternating current, and Edison was wrong about the advantages of direct current. See Current wars. Whether Tesla was right about wireless power has nothing to do with whether he was crazy. The question is which of his ideas about wireless power were sane and which were crazy. Robert McClenon (talk) 16:55, 5 August 2015 (UTC)

Wireless power gives a fair outline. Anything else you need to know after reading it?--86.144.255.14 (talk) 18:38, 4 August 2015 (UTC)

I see that Wireless_power#Far-field_or_radiative_techniques talks about point-to-point transmission, but they seem to be talking about much higher power levels and greater distances. StuRat (talk) 03:42, 5 August 2015 (UTC)

Broadcasting power requires either that you send little packets of electricity out (like sparks off a van de Graaf generator) or that you make use of a varying magnetic and electric field i.e. electromagnetic radiation. I think an issue with wireless power today is that anything powerful enough to run a lawnmower is going to be very hard to keep from interfering with your cell phone! Nonetheless, reading that article points out that you have applications like cell phone chargers. Powering something by a laser-to-solar-cell is also technically power radiation, and with ever more spy-y technology about, seems more believeable nowadays. Extremely low frequency is another option, though one that has some people very worried about potential health effects that remain controversial. And of course, you can always hold up a fluorescent bulb under a power line and see how much power radiation occurs inadvertently. But demanding the kind of power be beamed that can run a lawnmower? By definition, that has to be enough power to hurt - enough to run a blade you don't want going over your foot. However you move that energy, whether by super laser, microwave oven horn or some radio transmitter from hell, you do not want to get in the way of it as EM any more than you want to get in the way of the blade. Wnt (talk) 18:37, 4 August 2015 (UTC)

Is this a hoax, fraud or genuine revolution for hair loss treatment ?

We do not answer requests for medical or legal advice. See https://en.wikipedia.org/w/index.php?title=Wikipedia:Administrators%27_noticeboard/Incidents&diff=prev&oldid=645065201 by Doc James according to the Wikipedia:General_disclaimer and the guidelines at the top of this page. μηδείς (talk) 01:13, 5 August 2015 (UTC)

Does anyone know the use of this compass?

I found this compass in an old house and it has Chinese symbols on the compass part. I can't really find anything similar on the internet. I'm assuming this is a maritime compass but there a few odd things i can't figure out the use for. There's an opaque disk inside what looks like a telescope viewfinder on the bottom. And there is a screw on the top in the back which seems aligned with everything else, but i wonder why they would have that there unless you opened it up to let light in or something. It seems really well made and very heavy, the springs and mechanism on the base are all brass and very cool.

Pretty curious to learn more about this. If anyone has any ideas or knows where i can look for more information about ( what i assume is an old) compasses let me know.

http://imgur.com/a/W1EHl#x7gfBXJ

70.210.72.171 (talk) 17:56, 4 August 2015 (UTC)

Not much of an expert but I found this Japanese aircraft compass which is graduated in a similar way to your compass, although instead of "E" for east, yours appears to have the Japanese character for east. I also found Compass - Remote Reading, Japanese, circa 1945 which is in a similar type of binnacle to yours. I imagine it is easier to have the compass is another part of the aircraft to the cockpit so as not to have magnetic disruption from all the other instruments. Presumably there would have been some sort of optical sighting tube to allow the navigator to see it, perhaps the telescope-like attachment that you have. A lot of this is guesswork, so if anybody knows better, please feel free to correct me. Alansplodge (talk) 18:25, 4 August 2015 (UTC)

It sounds like the sighting scope is so they could identify the direction of a target.StuRat (talk) 22:48, 4 August 2015 (UTC)

wow very interesting, thanks for figuring that out, I guess I'll try searching information on Japanese world war 2 aviation compasses now. The sighting scope still seems weird to me I can't see how that would be useful since you'd have to hold it up in the air or something. 70.210.71.56 (talk) 00:39, 5 August 2015 (UTC)

If you remove the screw in the back, does that allow you to use the sighting scope by looking through that hole ? If so, there might have been another part to the scope to be attached in place of that screw. Also, is the whole upper part on a ball joint ? (It might be frozen up.) If so, it may be possible to use the sighting scope while the apparatus is bolted down. Presumably the compass does not move when the upper part, including the sighting scope, is moved. StuRat (talk) 03:57, 5 August 2015 (UTC)

The hole on the back (with a screw cap) was for filling the compass with liquid. You'd have to periodically drain/clean/refill it. 75.139.70.50 (talk) 12:52, 5 August 2015 (UTC)

Why was it filled with liquid and what liquid was it ? StuRat (talk) 15:55, 5 August 2015 (UTC)

The compass floats. It allows the compass to stay steady when mounted to an unsteady surface. I suppose it could use just about any liquid. The cheap one on my boat uses distilled water. 199.15.144.250 (talk) 19:04, 5 August 2015 (UTC)

(edit conflict) My father used to be a navigational instrument maker for both ships and aircraft, and he told me it was alcohol similar to surgical spirit. This article says purified kerosene is most common, but isopropyl alcohol is sometimes used (which seems to be the same thing as surgical spirit). The purpose is to dampen the movement of the needle; if you have a cheap compass without liquid, the needle jiggles about like a demented thing and is very difficult to read accurately. Alansplodge (talk) 19:07, 5 August 2015 (UTC)

Maybe the "sighting scope" is for attaching a small lamp and socket? is the opaque disc completely opaque?—eric 01:13, 6 August 2015 (UTC)

The sighting scope is not completely opaque, you can see if there is light behind it or not but that is about it. It seems weird that it should be filled with liquid since it works perfect without it. Should i fill it up with rubbing alcohol to preserve it? 70.210.76.110 (talk) 01:33, 6 August 2015 (UTC)

Now that's a request for advice, which according to the guidelines people on the Refdesk aren't supposed to give because we aren't experts and, so far, it sounds like nobody here has touched one of these before. Wikipedia disclaims all responsibility, so if you ruin a valuable antique based on what you read here there's no redress. Wnt (talk) 13:55, 6 August 2015 (UTC)

Pure alcohol might tend to preserve it, by killing microorganisms growing on it, but the "alcohol" commonly available to consumers is mostly water, and that would promote rusting. StuRat (talk) 14:01, 6 August 2015 (UTC)

Do we gain/lose self-awareness as we grow older?

I was walking past a high school this morning and suddenly I was reliving being back in high school. I was wearing a flannel shirt tied around my waist by chance (why, no idea, it's boiling outside) and I used to wear flannels like this all the time back in the 90s, so everything sort of clicked and I recalled myself walking about high school being completely "aware" of myself, a bit self-conscious, shy, and all that good stuff. I felt almost exactly the same, and a strange thought occurred to me: I seem to be as self-aware as I was 20 years ago. So I guess that's a good thing.

I ask because sometimes, being an adult now, I notice myself reacting less to certain things. I don't laugh as hard or as silly as I would as a teenager. I'll nod and concede that I'm amused, for example. Or I'll do things with less flair and conscientiousness for others, sort of like a robot would; from checking into a hotel and just talking automatically rather than being actually engaging. I've noticed these little things recently and wondered to myself, am I losing my "self" to something? Not sure how else to ask this question. Thought I would pose it here in science rather than a more philosophical board; hope that's alright. Reflectionsinglass (talk) 18:02, 4 August 2015 (UTC)

Wikipedia has an article on the Aging brain which may lead you interesting places in your research to answer your question. --Jayron32 18:42, 4 August 2015 (UTC)

If your attitudes and awareness didn't change as you aged then presumably you would be an eternal teenager, which despite the opinions of teenagers, is not a great thing.Greglocock (talk) 23:49, 4 August 2015 (UTC)

NASA VTOL aircraft testing at Moffett Field in the 1950's

In the 1950's I had a chance to see a duel counter rotating prop driven fixed wing aircraft being tested at Moffett Field Ca. I would like to find out what model it was and some history on it. I think it was made by Bell, but I am not sure. My memory shows it tethered to a semi flatbed trailer in the vertical position. If anyone knows anything about an aircraft of this type I would appreciate any information you could give me.

THANKS

Richard — Preceding unsigned comment added by 184.12.238.208 (talk) 19:41, 4 August 2015 (UTC)

In the 1950s, the Convair XFY-1 Pogo and the Lockheed XFV-1 were the two U.S. experimental tail-sitters with counter-rotating props. If you look at the pictures in the two articles, you can presumably identify the one you saw. Deor (talk) 20:23, 4 August 2015 (UTC)

There was also the Hiller Helicopter Demonstration facility, located on the site of what is now Facebook headquarters building on Willow Road - which was, at the time, part of the city of Palo Alto. (Reference: Over Time: Palo Alto, 1947-1980 (General History: California), by Ben Hatfield and Barry Anderson). This facility was, as you know, not actually building helicopters or VTOL aircraft; it was in fact recently declassified, as scheduled; it was as published in Year 2006 part of the National Reconnaissance Office's Project CORONA. A variety of "unique" helicopters were demonstrated at Palo Alto and at Moffett Field (presumably these were to distract attention from the true nature of the NRO program). Among the interesting VTOL aircraft was the Hiller X-18 with counter-rotating propellers (which is sometimes considered a grandfather of the V-22 Osprey). Nimur (talk) 22:03, 4 August 2015 (UTC)

Some more great resources:

• Ames Rotorcraft webpage, including free books!
  • Autogyros, Helicopters And Other V/STOL Aircraft, Volume I and Volume II (free books!)
• The Hiller Museum, which is located a few minutes north (by aircraft) at San Carlos Airport
• SP-3300: Flight Research at Ames, 1940-1997, a full and very thorough book that covers almost every weird Government Airplane (or similar) that flew out of Moffett for the greater part of the 20th century. They have some nice photos of gyrocopters, tilt-rotors, "vertiplanes," and all sorts of other weird contraptions.

Nimur (talk) 00:17, 5 August 2015 (UTC)

THANKS!! I had seen the Convair XFY POGO also, but it was the X-13 Vertijet that I was trying to remember. I had the two confused.

August 5

Can anyone identify this plant?

Found near Whitney Portal, July, 2015. --Trovatore (talk) 02:08, 5 August 2015 (UTC)

I am not good at plant identification, but Flora of the Sierra Nevada alpine zone is a good starting point. Do you recall at which approximate altitude you found the plant? The biomes change dramatically in the Sierras.

If you found it at lower or moderately high altitudes, it might be on List of plants of the Sierra Nevada (U.S.). (It looks like your photo is still in a forested zone).

Nimur (talk) 02:42, 5 August 2015 (UTC)

Roughly 2900 m (9500 ft), if that helps. --Trovatore (talk) 03:07, 5 August 2015 (UTC)

I'm going with cow parsnip - but please recognize that I am not an expert plant identifier. The leaves are not an exactly perfect match, but the general appearance is similar.

I came to this conclusion by pulling out a copy of my not-quite-field-portable guide book, The High Sierra (1972). It has an entire chapter on plants of the high sierra. Nimur (talk) 03:27, 5 August 2015 (UTC)

Ah, thanks much. Could well be. It certainly appears to be one of the Apiaceae in any case, which includes some harmless plants and some very nasty customers. For what it's worth, I tasted it, and I didn't die, though that doesn't prove much as I could hardly have ingested more than microgram quantities. It was not unpleasant, rather like pine needles. But I don't recommend anyone else repeat the experiment. --Trovatore (talk) 03:41, 5 August 2015 (UTC)

Strange. I was in this area four years ago and didn't find this plant.--Jasper Deng (talk) 09:29, 5 August 2015 (UTC)

• Definitely one of the Apiaceae, but without a clear picture of the leaves it's very difficult to pin down. Cow parsnip has quite large leaves, and I can't see any sign of them in the picture. One strong possibility is Angelica, specifically Angelica lineariloba (also known as "poison angelica", hint hint), which is widespread in that area. Looie496 (talk) 13:31, 5 August 2015 (UTC)

I was going to say angelica, but I was thinking of the edible kind - Angelica sylvestris - but I think you've hit the nail on the head. Alansplodge (talk) 17:35, 5 August 2015 (UTC)

Tasting it is certainly not a good idea. Although it's impossible to tell the size of the plant from the photo, it looks a quite like (and is at least related to) a plant that is spreading across many parts of the world, including the US, known as the Giant hogweed whose sap can cause severe burns with long lasting effects. It tends to attract attention as it grows very tall but is best avoided.[14] Richerman (talk) 09:00, 6 August 2015 (UTC)

geometric plane

hi, i want to find some geometric detail as described below: i need to find the equation for displacement in centroid of a triangle on displacing each of vertex of triangle independently in z direction. please tell me,where to get reference material. SD — Preceding unsigned comment added by Sameerdubey.sbp (talk • contribs) 05:59, 5 August 2015 (UTC)

If I've understood you correctly, and the triangle is in the XY plane, then the centroid just moves one third of the displacement of the vertex, since the centroid is two-thirds of the way down each median. I expect that someone else can give you a more general formula with references. Dbfirs 07:04, 5 August 2015 (UTC)

...which means that if all three vertices move in Z, then the centroid is displaced by one third of the sum of the three vertex movements - which is more easily stated as "the average of the three vertex movements" - which is kinda what you'd hope it would do! SteveBaker (talk) 14:42, 5 August 2015 (UTC)

• The coordinates of the centroid are the average of the coordinates of the vertices; it follows that the movement of the centroid is the average of the movements of the vertices. (For future reference, you might note that we also have a Mathematics Desk.) —Tamfang (talk) 04:31, 6 August 2015 (UTC)

Is the length of a river well-defined?

I was looking at the list of rivers by length and found that there appears to be no concrete definition of the length of a river. The length of the shorelines of a river is not well-defined because of the coastline paradox. Because river channels are, in general, quite irregular in shape, especially near the sources, I think it is futile to define the length of a river.--Jasper Deng (talk) 09:28, 5 August 2015 (UTC)

The length of a river cannot be measured exactly. This is discussed and explained at List of rivers by length#Definition of length, which you appear to have read.--Shantavira|^{feed me} 12:32, 5 August 2015 (UTC)

The question "is the length of a river (or coastline) defined to infinite precision", the answer (because of the coastline paradox) is "no". However, you can define a river (or coastline) length by constraining your definition to certain tolerances and resolutions, for example by creating an algorithm that maps a series of line segments of defined length onto the course in question; the line segments can then be summed up, and a useful and meaningful length can be created; you just need to know what definition and algorithm you're working with so you know how the result was obtained; the result of a good algorithm should, within any reasonable precision, provide an answer which matches the sort of physical experience people would expect. For example, people who want to know the length of a coastline really probably want to know "If I walked the entire coastline, how far would I walk." If your algorithm produces the same result as the experiment if you actually walked it out, then it's a useful one. A simpler way to think of it is like trying to apply the Koch snowflake to a much simpler polygon. Yes, the Koch snowflake is an interesting idea (in the same way the coastline paradox is), but the Koch snowflake does not mean that we can never give a meaningful answer for the perimeter of a polygon. The same with the river length/coastline paradox issue. --Jayron32 12:44, 5 August 2015 (UTC)

No, the "If you walked the coastline" test doesn't work because it depends entirely on how closely the person followed it, whether they walked into every tiny inlet and out onto every prominence - it has the very same fractal problem that is discussed in the coastline problem.

One solid definition for coastlines is the convex hull - which is consistent, well defined - but highly unsatisfactory for coastlines with large-scale concavities. But for rivers, one might take a similar approach by hammering a stake into the riverbed at the source, tying a rope to it and letting the rope follow the river to the center of the mouth. Pulling the rope as tightly as possible without it disturbing the banks would provide an unambiguous measure of "length" - presuming that you have a solid definition of which tributary is the "true source" and which exit to the ocean is the final end of the river, that the path of the river through tributaries is agreed and that the rope is infinitely thin and flexible.

That's not so easy in practice. Consider the mouth of the River Thames in England - which doesn't have a very clear and obvious transition into "ocean" - is the "end" at the mid-point of the tip of the Isle of Thanet and Foulness Island - or is it more like halfway between Southend and Sheerness? We could make a definition for the mouth such as "when the outflow crosses the convex hull of the surrounding land"...but that's not particularly acceptable when an entire continent has a large concavity such as with Rio Lluta at the border of Peru and Bolivia.

But if you have those definitions, then as a theoretical approach, the "rope stretching" thought experiment gives you the shortest path from source to mouth - which is a reasonable, finite and consistent measure. However, it's doubtful that this approach is practical in reality because you can't stretch the rope in that manner without having to worry about waterfalls, rocks that stick up out of the water and the curvature of the earth - to pick just a few examples - so if you can't do it in practice - you're entirely reliant on the precision of maps - and those suffer from the exact same fractal problem. SteveBaker (talk) 14:39, 5 August 2015 (UTC)

Only if you leave the definition of the walk undefined. Again, you can create a practical definition for "how closely to follow the coastline", and that will give you a real answer which is really useful. The paradox only comes into play where you leave your definition at infinite precision; it's like the Koch snowflake problem again: once you define a polygon as having a finite number of sides, you can find a real perimeter. It only becomes an undefined (or infinite length) perimeter if you demand that the Koch snowflake have an infinite number of sides. Your coastline is only undefined if you demand that one follow the coastline to infinite precision. If you allow the edges under a certain dimension to be rounded off, and allow the walker to "skip" following perterbations under a certain scale, you can define the coastline of a certain length. The coastline paradox is a classic example of where the usefulness of a mathematical model breaks down in the face of a real application. If I launch a boat in Oxford, and I want to know how far the boat will have traveled by the time it gets to London, I can do that so long as I define the trip to a reasonable (instead of infinite) level of precision. --Jayron32 15:09, 5 August 2015 (UTC)

The ambiguity of a coastline length and the ambiguity of a river length seem to be different issues. The length of a coastline is difficult (or impossible) to measure, because you can always zoom in closer and find more convoluted indentations to increase the overall lenght. A river doesn't have that problem, at least not if you measure its length along the median line. Infinitely convoluting the banks won't increase the overall length of the median line. The ambiguity of a river's length seems to be due to arguments about which tributaries to include, how to define the start when the river may be e.g. gradually emerging from a wetland, and actual physical changes in length or course of the river (not all or any of which need apply in all cases). Iapetus (talk) 15:23, 5 August 2015 (UTC)

Infinite series can converge. In other words, even if the coastline or the river (or the abstract mathematical path) has infinite complexity, it may have a finite and well-defined length. This is possible if certain specific mathematical properties of the path are conserved. It so happens that these properties match our intuitive expectations of a real coastline, or a real river path! In other words, there is no "paradox" in the coastline length. If you apply a mathematical model incorrectly, you will compute a wrong (or infinite, or undefined) result... but that ought to clue you in to the fact that you're not using the correct model!

Real coastlines and rivers have complex shapes: but even if we trace the paths ad infinitum to describe their smallest, most minute details, they still are not true fractals in the absolute mathematical sense. Fractals have specific mathematical properties that are described by recurrence relations. The perimeter or path-length for some fractals does indeed diverge (i.e. the length is not well-defined). However, it is a terrible and incorrect myth to assume that any and all complex shapes are fractal! There are many cases of non-fractals in analytic geometry, where we can study infinite numbers of infinitesimal features - like a river squiggling its way through a path, or a coastline curving and squiggling along - and the integral of the length over all these tiny path excursions need not be divergent. We can work with infinities and limits and infinite quantities of very tiny curves - modern mathematics provides us with lots of tools for that - but we must do so carefully in order to avoid incorrect conclusions.

I come from a background of digital signal processing. When I look at measurement of a pure mathematical curve, I know its exact equation; but when I consider the curve that approximates a shape in nature - like a waveform or a path of a river on a map - I am always thinking about a few ideas: in particular, I think about the sampling theorem, and I think about spatial filtering. The river's path is not an exact analytical curve defined by an equation that we already know. So, we are not actually measuring the length of a river: we are, in fact, computing the length of a river, whose path sampled at the spatial resolution of our map, and filtered by our smoothing functions (in geographic information systems, we use spline equations fitted to the data, which in essence is the application of a type of low pass filter). We can know whether these preprocessing steps introduce errors: we can resample at a lower (coarser) granularity. If the result is dramatically different, we have insufficient sampling. By the time we have appropriately sampled the problem, we compute approximately the same result - even if we cut the sampling rate by 2x or 10x. In other words, the length of the river (or coastline, or path) has converged. This is a numerical computation trick that works across the board in many domains where our model of the real world is discretized. At its core, this is the same mathematics as Von Neumann stability analysis - we are checking if we have created a numerical error by choosing an inappropriate value for the differential path element.

All these ideas - most particularly, the difference between "defining" and "measuring" and "computing" - are swirling around... and these are actually really important topics to explore. Mathematicians, geographers, and computer programmers mean something different when they say words like: define, "well-defined," "measure," "length," ... so you'll get a different answer depending on who you ask.

Nimur (talk) 15:36, 5 August 2015 (UTC)

@Wardog: I'm not so sure, because then how can I be guaranteed that the median line itself is rectifiable? To me this line would be defined by the midpoint between the banks, and I don't think this would be any smoother than the shorelines.--Jasper Deng (talk) 17:51, 5 August 2015 (UTC)

Yeah - I agree. A small pebble on one side of the river still perturbs the mid-line by half the width of the pebble - and river banks are just as fractal as coastlines (the fractal dimension is likely to be different - but the resulting length is still infinite). The problem of defining how small of a feature is counted still applies - and without counting, the length of the median is still infinite. It's precisely the same as the coastline problem...except that, with a coastline, the "convex hull" (which is well defined) seems an inadequate measure - where the 'tightly stretched rope' approach that I described doesn't seem so horrible in the case of a river.

What fails in every case (for both rivers and coastlines) is that people insist on telling you the lengths of those things WITHOUT adequate stipulation of the definition for what is being measured. That's weird because nobody ever tries to tell you the circumference of a cloud - and that's the same exact problem. SteveBaker (talk) 18:10, 5 August 2015 (UTC)

@SteveBaker: That's not quite right. The median line gets effectively smoothed by the width of the river. If you have a river with some minimum width w, then the radius of curvature of the median line won't be smaller than something like w/2. You have to put the median line equidistant from the nearest point on each shore. --Amble (talk) 19:21, 5 August 2015 (UTC)

I want to reiterate: the paths that follow the edges coastlines and rivers are not fractals. Even our article, coastline paradox, explains that they are "fractal-like." These paths have properties that are fractal-like; but fractals are non-differentiable. That property is a very important one: it's the key to the whole "fractals have no well-defined length" paradox. Does that specific mathematical property - the non-differentiability - apply to the edge of a river bank, or to the path between the sea and the land? If that non-differentiability property does not apply, then the path is not a proper fractal. The ambiguity in defining the path length, therefore, is not because the length is infinite. The ambiguity ultimately stems from some other error in the construction of the problem. At best, these natural shapes are convenient analogies for the mathematical abstraction that is a fractal curve.

Let's especially distinguish between a path whose length is infinite, and a path whose length is ambiguous; and distinguish both of these cases from a natural shape whose path is not easy to describe with an analytical equation. These are all completely different concepts.

Nimur (talk) 19:39, 5 August 2015 (UTC)

An arc does not even need to be differentiable to have a well-defined length - the definition at arc length specifically does not require it. But coastlines (including river banks) do fail to even be continuous, let alone differentiable. If you look at the boundary between the water and the land, it is not a single line. Waves and water levels change that too, and then when a tributary enters, where do you demarcate where the tributary ends and the mainstem begins? Hence the median line cannot be considered to be smooth either. The concept of a median line also becomes ill-defined for braided streams.--Jasper Deng (talk) 22:09, 5 August 2015 (UTC)

@Amble: Also, that is not of any use because the minimum width of a river at its source is usually a very small length. And that still leaves ambiguity of where to place the median line when the river is substantially wider than w.--Jasper Deng (talk) 22:15, 5 August 2015 (UTC)

@Jasper Deng: You can always inject some degree of uncertainty, but the specific claim I was responding to -- that the median line is some untameable fractal beast with infinite length -- is simply incorrect. The indentation level of my posting indicates threading per WP:INDENT, but since this rule isn't much followed these days, I suppose I need to train myself to explicitly include a ping or username every time. --Amble (talk) 22:32, 5 August 2015 (UTC)

Given two agreed upon points in the water, there is a well-defined minimum possible path length between them subject to the restriction that the path never leaves the water (or the water as it exists at some fixed instant in time anyway). For me, that seems like a reasonable definition for the length of a river provided one can agree on start and end points (which can be a rather thorny issue). This speaks to Steve's rope stretching analogy, and essentially gives the minimum distance a traveler must cover if moving along the river from start to end, which seems like a useful notion. Of course, in practice, river lengths are really always measured by creating a map with some finite level of detail and then measuring the course of the river on the map, in which case the answer will depend on the precision of the map. A cartographer might also try to create a fancy mid-river path rather than the shortest within river path, but that's mostly an issue of preference. Dragons flight (talk) 22:28, 5 August 2015 (UTC)

5 Alpha Reductase

There are many 5 Alpha Reductase inhibitors in natural organic forms. Do they really inhibit 5AR enough to decrease Di Hydro Testosterone as a result ?? — Preceding unsigned comment added by 103.15.60.58 (talk) 12:11, 5 August 2015 (UTC)

5-alpha-reductase inhibitor discusses testosterone inhibition and use in male and female pattern hair loss. Though our article mentions a large array of plant-derived inhibitors, it currently calls their effectiveness "unknown", and frankly, I don't want to take the time to run down every single one in PubMed right now to see if any further data is in about them. Wnt (talk) 16:23, 5 August 2015 (UTC)

Kidney transplant life expectancy

Hello, What was the life expectancy for a kidney transplant patient in 1975? Thanks, Chris. — Preceding unsigned comment added by 31.52.165.152 (talk) 18:06, 5 August 2015 (UTC)

According to this study the life expectancy in 1989 in Scotland was 17.19 years vs 5.84 for those on dialysis. Ruslik_Zero 19:26, 5 August 2015 (UTC)

Nylander's test

Do we know after whom Nylander's test is named? DuncanHill (talk) 22:28, 5 August 2015 (UTC)

Based on [15], I believe the answer is Swedish chemist Emil Nylander (1835–1907). Dragons flight (talk) 23:32, 5 August 2015 (UTC)

I am finding mostly Almen-Nylander test, and one Böttger-Almen-Nylander test. sv:August Almén maybe?—eric 01:42, 6 August 2015 (UTC)

de:Claus Wilhelm Gabriel Nylander? —eric 01:47, 6 August 2015 (UTC)

de:Nylanders Reagenz agrees that his work was the final stage in an evolution of tests based on work of Böttger and others. And that he published the work under the name "Emil Nylander". The birth/death years in the DEWP article Eric linked match what Dragons flight mentions, supporting that they are the same person (I just created a REDIRECT on DEWP for it). DMacks (talk) 09:13, 6 August 2015 (UTC)

Rudolf Christian Böttger.—eric 02:03, 6 August 2015 (UTC)

August 6

Quiet birds

Apologies for starting three sections at once.

The other day I noticed that some snow buntings had built a nest on an I beam under our building. This puts the nest about 70 cm (28 in) above the ground and better protected from predators than normal. Because finding a nest isn't common I decided to take some pictures. Every time the shutter went off the birds opened their mouths for food. However, it wasn't until later that I realised they were completely silent and still are 5 days later. Now this makes sense for birds who nest on or close to the ground. But other birds who don't quite often have young who are vocal.

So the questions are:

1. Do other ground dwelling birds remain silent until grown?
2. What advantage, if any, is there to birds who nest higher up to have young who are more vocal? CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 04:56, 6 August 2015 (UTC)

For starters, see Altricial - high nesting birds do indeed tend to be more altricial than their ground-nesting counterparts. See also Begging_in_animals#Auditory_signals - the noisy bird (often) gets the food! SemanticMantis (talk) 13:41, 6 August 2015 (UTC)

Thanks. The chicks are still silent. I suspect that the birds don't nest close together so there is little need for them to be noisy. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:37, 7 August 2015 (UTC)

Egg laying

As it points out in the snowy owl article they lay their eggs every other day leading to a large difference in size between the first and last hatched.

So the questions are:

1. What advantage, if any, is there to laying eggs spaced out like this?
2. Are there any other animals, birds or not, that lay their eggs over a period of time? CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 04:56, 6 August 2015 (UTC)

We have seen on BBC Springwatch examples of this across the owl family. Their resident naturalist (Chris Packham) explained it as "lay the brood - lay the food". In other words, the older chicks will eat the youngest ones during times of relative famine. This has been filmed by them. --TammyMoet (talk) 08:30, 6 August 2015 (UTC)

Just to expand on this slightly. The timing of egg laying is so that the earlier laid eggs produce significantly larger chicks. So, when times are tough and the chicks perform siblicide, one of them is it a clear advantage. This prevents equally sized chicks fighting it out and possibly both dying. Nature can be cruel, but beautiful in design.DrChrissy ^(talk) 13:48, 6 August 2015 (UTC)

Most birds do lay over a period of time. This is sort of an energetics and physiology issue. How could e.g. a mallard hold ~12 eggs inside before letting them all out at once? There is a ton of research into describing the patterns of laying period and clutch size in birds, and understanding the ecological and evolutionary forces that control them. For a general idea, try skimming /laying period clutch size interaction/ in google scholar [16]. (The abstracts are almost always free, and if you past the full title in to regular google you can often find freely accessible copies) SemanticMantis (talk) 13:47, 6 August 2015 (UTC)

I'd done some checking because the snowy owl article says they don't siblicide but it isn't referenced. Unfortunately, almost everything I found confirming that had been copied from Wikipedia. One thing I did find was this which indicates that they may regulate their egg laying based on the food supply. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:41, 7 August 2015 (UTC)

I concur with both reasons given. As for being unable to lay multiple eggs at once, in this respect they may be similar to humans. Yes, humans can have twins, triplets, etc., but the more babies at once, the smaller each one is and the more likely each will have medical problems. StuRat (talk) 03:28, 7 August 2015 (UTC)

r-k selection is also relevant to this and the question below. SemanticMantis (talk) 14:16, 7 August 2015 (UTC)

Disappearing wildlife

Normally in the spring we (Cambridge Bay) get hundreds of geese on either side of the road to the airport and hundreds more in the large pond at the end of the runway. However, this year there were very few. Wondering if I was just imagining it I checked and others had noticed it too. I then realised that other bird species like the snow buntings, small brown birds (official name), gulls, terns and even the ever present ravens were visible but in much smaller numbers. Then a couple of days ago we were down on our local beach, frolicking in the Arctic Ocean, when someone commented that there were very few mosquitos. This also applies to regular flies, which I don't mind at all, that normally number in the hundreds in one of our buildings. So what would cause the sudden lack of these animals? I know that we had a early spring and July seems to have been very wet but would that factor into it? Sorry again for three sections. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 04:56, 6 August 2015 (UTC)

When a wife disappears, the default suspect is the husband. When the wildlife disappears, it's usually your fault. "You people", anyway. Harder to pin down the specifics, but the way my wildlife fell just a few years after the West Nile panic sprayings has my spidey senses tingling. Still a ton of mosquitoes (and new big, crunchy yellow ones), so it's not like they're going hungry. I just don't think this new kind of bug is very healthy. Only one piece of the puzzle, though, even if true. InedibleHulk (talk) 07:35, August 6, 2015 (UTC)

Well, the lack of mosquitos and other food sources could be a an example of bottom-up control. See e.g. here [17] for a quick primer, here [18] for some hard science papers, and our scant WP coverage is at Top-down_and_bottom-up_design#Ecology. You can play with this interactive mapping tool [19] to see how mosquitos are currently doing. They generally do worse in harsher winters and dryer springs, not sure what you had this year.

Also keep in mind all populations fluctuate in their natural conditions, sometimes wildly. A famous example comes from your neck of the woods (roughly), elucidated by trapping data from the Hudson Bay company, showing the boom/bust cycle of lynxes and hares [20]. Finally, the weather is weird in much of the world this year, a likely record-breaking ENSO is already pushing temp and precip patterns around the word far from their seasonal norms. Many birds do " facultative migration," meaning they stay or go based on how good their current locale feels. So maybe some of these birds are just staying elsewhere this season. As far as specific scientific explanations of causes for this phenomenon this year, you'll have to wait a year or so, collected and analyzing such data takes time. SemanticMantis (talk) 13:38, 6 August 2015 (UTC)

FWIW, further south in Ontario we've had bumper crops of mosquitoes this year. You're quite welcome to come collect as many as you need to feed your birds. :) 64.235.97.146 (talk) 14:05, 6 August 2015 (UTC)

I think a more famous example of population fluctuations are these animals. Although are winter was mild, and they have been for several years, in that the temperature didn't drop below −40 °C (−40 °F), spring came early. We had warm above 0 °C (32 °F) for a while and then a drop below freezing for 2 weeks. June wasn't too bad for rain but July was very wet. Even after the rain stopped there were few mosquitoes around. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:50, 7 August 2015 (UTC)

Since Canada geese are migratory, the obvious answer is that they've migrated on. If it's now warmer there than normal, they might have migrated farther north to take advantage of the food up there. StuRat (talk) 03:23, 7 August 2015 (UTC)

See the "Ugly duckling" section just below. Nyttend (talk) 04:12, 7 August 2015 (UTC)

Can the hairs and the fingernails be regarded as a "benign growth", according to its scientific definition?

HOOTmag (talk) 06:48, 6 August 2015 (UTC)

I don't know what sort of science you trust, but by this medical dictionary, they're disqualified for not being abnormal. Definitely "benign", unless you develop a new form of fingernail or hair cancer. InedibleHulk (talk) 06:58, August 6, 2015 (UTC)

• Terms are distinguished by not only what they include, but also by that which they exclude. See genus–differentia definition. The term benign in medicine is differentiated from malignant, and these are subgroups of tumors; that is, abnormal growths. If you are going to call hair "benign", you will end up having to call kidneys, teeth, lungs, etc., benign on the same basis. You've removed the essential genus "abnormal growth" and simply defined benign to mean anything non-cancerous. Of course you are free to use your own definitions, but if you go to the doctor and tell him to remove your malignant hair, he is not going to give you a nice hairdo. μηδείς (talk) 17:08, 6 August 2015 (UTC)

What prism would neither rotate nor invert an image after 90 degrees reflection?

What prism would neither rotate nor invert an image after 90 degrees reflection? Imagine that two persons are sitting at an angle of 90 (considering their gaze). One of them is looking at an object directly. What prism should the other have to look at exactly the same image? I know that a roof pentaprism + mirror would do the trick. But what about an optical component without mirror? --3dcaddy (talk) 20:19, 6 August 2015 (UTC)

If I'm reading pentaprism correctly, that would not require an additional mirror (note: "pentaprism" not "roof pentaprism"). Also, in these contexts, a prism is just a block of glass, some of whose internal surfaces act as mirrors. An optical arrangement of interest might easily be mappable from "mirror" to "prism" (or "extension of existing prism") by filling the space in front of the mirror surface with glass. DMacks (talk) 20:46, 6 August 2015 (UTC)

In the case of the pentaprism, the internal sides are coated to be mirrors. They don't just reflect the light internally through total refraction. Pentaprisms can even be substituted by pentamirrors. --Scicurious (talk) 22:05, 6 August 2015 (UTC)

Given a Rolleiflex, or any similar camera with waist-level viewfinder, could the camera incorporate a prism to let the photographer see the image as it would see it using an SLR?

I understand that the lens of the camera flips the image both top-down and left-right, and the mirror flips the image top-down. That leaves us with an image which is flipped only left-right in the case of the Rolleiflex. And a correct image, in the case of the SLR which has a lens + mirror + roof pentaprism. Couldn't a prism instead of the mirror correct this problem for the Rolleiflex?

If I understand correctly, having a pentaprism (not the roof pentaprism or a SLR) instead of a mirror, would flip the image top-down and left-right, leaving us with a correct image. Is that correct?

I wonder too why doesn't an upmarket camera like the Rolleiflex incorporate then a pentaprism instead of a mirror. --3dcaddy (talk) 01:20, 7 August 2015 (UTC)

Ugly duckling

On the Mississippi River below the Quad Cities

What's the ugly duckling? Some sort of domesticated duck gone feral? Nyttend (talk) 03:09, 7 August 2015 (UTC)

Looks like a plain old white American goose (not sure what the official name is) in with a bunch of Canada geese. Those white gees used to be widespread until the Canadians moved in and took over. StuRat (talk) 03:18, 7 August 2015 (UTC)

You're joking, right? Canada geese can be problems at e.g. golf courses, and their numbers and migrations patterns have been changing. This is all covered in the article you linked. But their native range has included most of the USA, and in fact there used to be a lot more of them in the USA. There are historical reports of flocks in CA that would block out the sun for hours. SemanticMantis (talk) 14:22, 7 August 2015 (UTC)

Plain old snow goose, not to be confused with invasive Canadian snowbirds. InedibleHulk (talk) 04:41, August 7, 2015 (UTC)

I've seen the Snowbirds; they're pretty impressive, and they go back up north pretty quickly. But InedibleHulk, this was just taken last week, not in January, and the bird's breeding range is up in Nunavut. I'm finding publications like [21] when looking for information on summer ranges, and nothing's mentioning a sustained summer population in the central USA. Nyttend (talk) 12:11, 7 August 2015 (UTC)

That probably explains why there's only one. Filthy vagrant. Hanging around in strange neighbourhoods can be safer than flying, if you're not bigger than the plane. InedibleHulk (talk) 12:22, August 7, 2015 (UTC)

This is what an ugly feral duck looks like. That's probably not even the wildest monstrosity of the flock. Lock up your wives and children, Florida! InedibleHulk (talk) 09:49, August 7, 2015 (UTC)

Mine is uglier than yours![22] - don't you just love caruncles!DrChrissy ^(talk) 12:50, 7 August 2015 (UTC)

I can never love again, thanks to Jim Henson. InedibleHulk (talk) 13:06, August 7, 2015 (UTC)

User:Nyttend - many birds' patterns of migrations are changing with land use change and climate change. Not all Canada geese migrate. Some of them just stay at shopping malls and golf courses and don't move much. As for snow geese, this page [23] says they were spotted in PA in April, which is also inconsistent with a too-literal reading of our range map. But, also consider that it may just be a feral domestic goose. I can't tell from the photo, but WP:OR I've seen plenty of odd domestics hanging out with flocks of Canada geese. SemanticMantis (talk) 14:14, 7 August 2015 (UTC)

Testing theory of evolution empirically

The theory makes sense and all, however, scientific is not what makes sense, but what stands after empirical testing. So, what could falsify the hypothesis that living beings evolve and are naturally selected? Is there anything that if exists, would make theory of evolution questionable? Couldn't it be that somewhere on Earth all kinds of creatures were created spontaneously (not implying there is a god) and they emigrated to the most convenient environment to survive?--Scicurious (talk) 13:04, 7 August 2015 (UTC)

Modern_evolutionary_synthesis#The_modern_synthesis is a good place to start. SemanticMantis (talk) 14:06, 7 August 2015 (UTC)

Also remember that the standard of empiricism and falsifiability is not necessarily an organized experiment, but rather the gathering and analysis of evidence. Where evidence already exists, experiments do not need to be specially organized to create it. Science is fully capable of gathering evidence which is already lying around, and organizing, analyzing, and drawing conclusions from that already existing evidence. The test is in the form of gathering evidence (geologic evidence, fossils, genetics, etc.) not in setting up an experiment in a laboratory and having a scientist wander around with a clip board watching it happen. --Jayron32 16:09, 7 August 2015 (UTC)

Your question makes the statement "living beings evolve." That is false. It is not part of evolution. It has never been part of evolution. It makes no sense. It is nothing more than an argument by religious zealots to discredit evolution. Species may (or may not) evolve over time. Individual beings do not evolve in any way. Evolution is merely the propagation of generic mutations from one generation to the next. It is not a change in the genetics of an individual being. However, it is apparently impossible to make this point understood. 209.149.114.32 (talk) 17:11, 7 August 2015 (UTC)