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June 13

Are there any living things in 4+ homographic taxonomic categories?

Gorilla gorilla gorilla is a subspecies of gorilla. None of it's other taxonomic classifications are "gorilla". It's tribe gorillini is close but no cigar. Sagittarian Milky Way (talk) 04:56, 13 June 2016 (UTC)[reply]

The first thing that pops to mind is Major Major Major Major, but of course that's not really what you're looking for. —Steve Summit (talk) 07:36, 13 June 2016 (UTC)[reply]

Let me see... Rattus rattus is a rat, Gerbillus gerbillus is a gerbil, Orilus orilus is an oriole, Iguana iguana is an iguana, Conger conger is a conger eel, Puffinus puffinus is the Manx shearwater, Boops boops is the Bogue fish, Mops mops is the Malayan Free-tailed bat, Megacephala (Megacephala) megacephala is a Tiger Beetle subspecies, and, if you are ready, Bison (Bison) bison bison is a subspecies of, you guessed it, bison. To conclude, just remember that Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo. JoshMuirWikipedia (talk) 09:22, 13 June 2016 (UTC)[reply]

Tautonym is the technical term, and List of tautonyms is the place to research this. No quadruples so far, but it's a long list. Tevildo (talk) 19:30, 13 June 2016 (UTC)[reply]

Try Cinclus cinclus cinclus, which is in the family Cinclidae. Tevildo (talk) 19:40, 13 June 2016 (UTC)[reply]

Colius colius, family Colidae, order Coliiformes. I'm going to stop now. Tevildo (talk) 19:49, 13 June 2016 (UTC)[reply]

this user enquires the harms that may occur from overconsumption of lemons

see the guidelines above, we do not know your frailties

The following discussion has been closed. Please do not modify it.

6 or more within 24 hours.immideatism for knowledgeFAMASFREENODE (talk) 11:25, 13 June 2016 (UTC)[reply]

Quoting the notice at the top of this page... "We don't answer (and may remove) questions that require medical diagnosis or legal advice."

That said, you might want to read Vitamin C#Overdose. Dismas|^(talk) 12:59, 13 June 2016 (UTC)[reply]

in reply to Dismas, the enquiry is performed as for general knowledge and refdesk is for itFAMASFREENODE (talk) 13:23, 13 June 2016 (UTC)[reply]

This indicates it takes a couple of lemons to make a single glass of lemonade. So you're talking 3 glasses to consume 6 lemons. If you have concerns about it, you should contact your doctor. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:49, 13 June 2016 (UTC)[reply]

Main Battle Tanks

Why Russian and British tanks have longer guns - main guns - than all other tanks ? Why German tanks have two types of guns , one short and the other is long ? 86.108.73.207 (talk) 13:08, 13 June 2016 (UTC)[reply]

Short-barelled PzKpfw IV Ausf F1 with the L/24

Long-barreled Ausf F2 with the L/43

What era? WWII? The "classic" example of this would be the PzKpfw IV, with the short 75mm and the long 75mm.

The first of these was a "heavy tank gun" intended as a dual purpose piece of tank artillery. It could fire either an armour-piercing shell against tanks, or a high-explosive shell against troops or buildings. At the time, this was a powerful tank gun. It was one of the few tanks which could carry such a large calibre (diameter) 75mm gun in a fully rotating turret.

The short barrel gives a short length in which to accelerate the shell. A longer barrel gives more length. So for the same round, the long barrel gives greater muzzle velocity. This doesn't matter much with an explosive shell: so long as it arrives, it will explode and do damage according to its filling. For an anti-tank armour-piercing solid shell though, the velocity with which it arrives is what gives it its destructive power. A longer gun will probably use a larger chamber and shell case for the round - the amount of propellant chosen is the amount that can be burned during the shell's travel down the barrel: a longer barrel gives time and space for more. It may need a larger shell case to make use of this though.

The first of these two guns was the L/24 variant, the longer was the L/43. This means that their calibre length (the length of the barrel as a number of diameters) was nearly twice as long for the longer barrel. It is more difficult to make the longer gun though: it is larger, harder to make such a long barrel, heavier (so the tank suspension might not cope), has greater recoil forces (so the turret bearing has to be stronger) and will probably use larger ammunition (so fewer rounds can be carried).

The US Sherman also had varying barrel lengths. The original gun was another short 75mm but the US lengthened it as the 76 mm gun M1 and the British installed their 17 pdr as the Sherman Firefly. The Fireflies' ammunition was so large (and powerful) that a crew member had to be left out to make room. Andy Dingley (talk) 13:51, 13 June 2016 (UTC)[reply]

Well I`m sorry I didn`t mention the era I`m asking about , I meant the third generation era , but the information is useful thank you very much . 86.108.73.207 (talk) 14:57, 13 June 2016 (UTC)[reply]

The following data applies to current main battle tanks. The Russian T-80 is armed with the 2A46 125 mm smoothbore with a barrel length of 52 calibers (6.0 metres). The British Challenger 2 is armed with the L30 rifled gun with a barrel length of 55 calibers (6.6 metres). The American M1A2 Abrams is usually armed with the 44 calibers (5.3 metres) version of the Rheinmetall 120 mm gun. However, many German supplied NATO armies using this gun have replaced it with the more powerful 55 calibers version where there is a possibility that they will have to face Russian T80s. So it is debatable whether the OPs contention that only British and Russian tanks have longer guns is correct. SpinningSpark 15:31, 13 June 2016 (UTC)[reply]

Our article gives a barrel length for the Rheinmetall L/55 of 6.6 m, the same as the L30. Alansplodge (talk) 20:35, 13 June 2016 (UTC)[reply]

Then I'd agree with Spinningspark. For recent tanks, I can't see a systemic variation between them. Andy Dingley (talk) 15:46, 13 June 2016 (UTC)[reply]

The Abrams is normally equipped with the L/44, not the L/55, which is indeed a shorter barrel. SpinningSpark 08:36, 14 June 2016 (UTC)[reply]

Thank you Spinningspark, Thank you Andy Dingley . 86.108.73.207 (talk) 18:06, 13 June 2016 (UTC)[reply]

Brian spider

There's nothing here about it, but it was a topic of Mark Trail several weeks ago. It's a newly discovered species named for someone named Brian.— Vchimpanzee • talk • contributions • 20:03, 13 June 2016 (UTC)[reply]

Actually, we do. Dolomedes briangreenei - see also this article from National Geographic. [WARNING - Article has large photo of said arachnid]. Named after Brian Greene. Tevildo (talk) 20:34, 13 June 2016 (UTC)[reply]

Okay, thanks. I just missed it somehow. And apparently I'm glad I did. Here is where I learned about the species.— Vchimpanzee • talk • contributions • 20:37, 13 June 2016 (UTC)[reply]

When I saw that, I assumed it was named after Brian Austin Greene. Thankfully not so. Justin15w (talk) 19:12, 14 June 2016 (UTC)[reply]

Every time I see this, I first read it as brain spider. Is that a thing? If not, it should be. --Trovatore (talk) 19:55, 14 June 2016 (UTC) [reply]

"In some spiders, the central nervous system took up nearly 80 percent of the space in their bodies, sometimes even spilling into their legs." [1]. Salticids in particular are super brainy and smart hunting spiders: some of their hunting techniques are comparable to lions', see Hunting tactics of the genus Portia. For extra cool/creepy points, they huntother, dumber, web-weaving spiders, in part by sending deceptive vibrational signals down the victim's web. So yeah, brain spiders :) SemanticMantis (talk) 22:01, 14 June 2016 (UTC)[reply]

Determining month and/or day in GTA by day duration

I'm particularly interested in GTA Vice City and GTA San Andreas. AFAIK, the day duration synched with clock in the upper right corner there is constant (and apparently it's the Northern Hemisphere), so based on day duration and daylight intensity I wonder what month and/or day would it be during the gameplay? Thanx.--93.174.25.12 (talk) 23:12, 13 June 2016 (UTC)[reply]

It would depend on the latitude of the location. Here's a calculator that shows amount of daylight on a specified day in a specified location: [2] CodeTalker (talk) 23:24, 13 June 2016 (UTC)[reply]

Day duration for San Andreas, California in 2016 is listed here [3]. That US Navy site can be configured for various places and years from this [4] interface. Then you can look up various Anytown, USA locations. This will only precisely work for the game if the designers cared about modeling the real world with respect to daylight duration in either the current decade or perhaps the decade of the setting of the game in question. I'm not sure but I think that for mid lattitudes the drift in ~50 years time is fairly small, and perhaps you can ignore year for game-estimation purposes. SemanticMantis (talk) 23:30, 13 June 2016 (UTC)[reply]

In case there's some confusion San Andreas in Grand Theft Auto was never presented as San Andreas, California but instead as a place containing parts of something similar to California and Las Vegas. In the specific case of Grand Theft Auto: San Andreas, it was an island (I don't think it was mentioned as an island but it was an island in game) containing 3 cities fairly loosely based on Los Angeles, San Francisco, and Las Vegas. See Grand Theft Auto (series)#Setting for more. Nil Einne (talk) 14:17, 14 June 2016 (UTC)[reply]

I believe that day and night always had the same duration in GTA:VC & SA, regardless of how many days had passed in the game. However, there was (at least in GTA:SA) a days passed counter in the stats. If you measure different lengths of day/night on different days and you know how many days have passed between measurements, I think 2-3 measurements should be enough to determine latitude and day of year. 78.0.238.197 (talk) 21:36, 16 June 2016 (UTC)[reply]

How many degrees above the horizon can the Sun reach? What time is sunrise? What time is sunset? How many degrees north or south of due west does the Sun set? (due south or north being the Sun's direction halfway between sunrise time and sunset time, if the game says otherwise then they screwed up). Sagittarian Milky Way (talk) 22:54, 16 June 2016 (UTC)[reply]

June 14

Woodward effect/Mach effect

is Mach effect thruster (MET) a anti gravity device? 81.216.64.211 (talk) 12:19, 14 June 2016 (UTC)[reply]

see Woodward effect 81.216.64.211 (talk) 12:20, 14 June 2016 (UTC)[reply]

No. The claimed thrust of the Woodward effect is as difficult to show as nett power from a Brownian ratchet. AllBestFaith (talk) 23:26, 14 June 2016 (UTC)[reply]

Clicker training yourself

Is it possible to use clicker training on yourself? Is there anyone who has tried this? What if you make a robot that recognizes and rewards the desired behaviour? (((The Quixotic Potato))) (talk) 13:37, 14 June 2016 (UTC)[reply]

At least some people think so. Usually I hear about snapping a rubber band on your wrist to help create an aversion to the targeted behavior, see e.g. [5]. I'll see if I can find any real science on efficacy. SemanticMantis (talk) 14:41, 14 June 2016 (UTC)[reply]

Oh wait our article says clicker training is only used for positive reinforcement. I think that's too narrow, and clicker training is also used as positive punishment in the real world, even if that's not best practice. But anyway, the rubber band thing I link is definitely an attempt to get self-applied operant conditioning to work on humans. SemanticMantis (talk) 14:45, 14 June 2016 (UTC)[reply]

For the more general scientific perspective, here [6] is a book chapter on self-management methods, giving an overview of some theory and empirical research, many more refs therein. It seems to address some of your questions, but maybe no specific evidence based on experiments with a rewarding robot. SemanticMantis (talk) 14:57, 14 June 2016 (UTC)[reply]

Awesome, thank you! I've been thinking about writing some software to train myself to do certain things (and stop doing other things). Unfortunately I am not yet able to build a cool robot, but that might be a project for the future. (((The Quixotic Potato))) (talk) 21:36, 14 June 2016 (UTC)[reply]

The click sound in clicker training has no intrinsic meaning and is a "bridging stimulus" whose perceived value (to reinforce or deter behaviour) has to be trained by context. Its practical value is that the click can be given so quickly within an animal's short span of attention to a single action that the animal becomes conditioned to identify the action with the (desirable or undesirable) significance of the click. Neither a human nor a potato has both the insight needed to conceive a click training discipline and an inability to know what is happening, so self training efforts must involve more complex mental assumptions than clicker training. It is trivial to program a robot to collect either maximum or minimum number of signals, which may be clicks, but both the robot and its programmer have much more to learn before self-intelligent evaluation of behaviour can be possible. AllBestFaith (talk) 23:15, 14 June 2016 (UTC)[reply]

Hydrogen Vs Earth

Newton had stated in his universal law of gravitation that every body in this universe attracts every other body by a force that is directly proportional to the product of masses and is inversely proportional to the distance between their centers. But why the hydrogen gas goes upward from earth's surface and doesn't get stuck at the earth surface? If you opine that it is due to the less mass of hydrogen, then you should think about the gravity of such great mass of Earth . Can't the Earth pull the Hydrogen on it's Surface ? Please You Can Give The Answer From Any Angle. — Preceding unsigned comment added by Achyut Prashad Paudel (talk • contribs) 15:13, 14 June 2016 (UTC)[reply]

The Earth is not a black hole. You leave fast enough, you escape. Sagittarian Milky Way (talk) 16:38, 14 June 2016 (UTC)[reply]

Is it reasonable to suppose that if the entire atmosphere of the earth were hydrogen, that at least some would "stick" near earth's surface? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:45, 14 June 2016 (UTC)[reply]

I'm pretty sure there was a lot of hydrogen in Earth's first atmosphere and it's now down to 0.000055%. Sagittarian Milky Way (talk) 17:42, 14 June 2016 (UTC)[reply]

Less than 4% hydrogen is not flammable if the remainder is a fine 2016 vintage air. Buy a bottle today! Recently coming with notes of extra CO₂, fallout, and a bouquet of various CFCs, the air of this upstart sentience in the Orion Arm is a unique addition to the collection of any imported air connoisseur. Are you an alien hipster? Want something to show how obscure you are? While everyone else drinks common nitrogen you could be drinking the liquified air of a hypertropical world no one's ever heard of called Earth. Buy your expensive craft brew today! Sagittarian Milky Way (talk) 17:50, 14 June 2016 (UTC)[reply]

Is it organic? (((The Quixotic Potato))) (talk) 10:34, 15 June 2016 (UTC)[reply]

Actually... Tevildo (talk) 18:09, 15 June 2016 (UTC)[reply]

Gravitation is not the only force acting between the Earth and the atmospheric hydrogen, atmospheric pressure is acting in opposition to it. Also, gravitation is a comparatively weak force – consider, for example, that the gravitation of the entire mass of the Earth pulling on a piece of metal can be overcome by a small hand-held magnet.

For more details, see the article Atmospheric escape. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 17:28, 14 June 2016 (UTC)[reply]

Also, solar wind. If he earth was stationary and in the middle of deep space, then the hydrogen would probably float up to the very top of the atmosphere and gravity would probably hold it there. But the earth isn't stationary and it isn't in deep space. We are fortunate enough to have a magnetic field which deflects most of the solar wind away from the bulk of our atmosphere, something which mars is not lucky enough to have which is the main reason mars has 1/10th the atmosphere of earth. Vespine (talk) 23:14, 14 June 2016 (UTC)[reply]

Hydrogen floats for the same reason a boat floats - because something else is being pulled down more. The heavier atoms crowd in underneath it, and eventually it rises. Indeed, it may be lost entirely from the exosphere - each stray molecule, depending on its particular speed, which is a random function of temperature, might reach escape velocity with some low probability. Heavier molecules move more slowly and are far less likely to have escape velocity at the usual exosphere temperatures. Wnt (talk) 23:57, 14 June 2016 (UTC)[reply]

The Earth's atmosphere is quite warm, almost 300K, depending on altitude, and at the highest altitudes it becomes less well defined as there are too few collisions to get thermodynamic equilibrium. The molecules in the atmosphere have a kinetic energy of, on average, the temperature times Boltzmann's constant. Hydrogen molecules are much lighter than nitrogen molecules (by a factor of 13.9), so they move on average 3.7 times as fast. That makes is far more likely for hydrogen molecules to reach escape velocity than for nitrogen molecules. Effectively, the hydrogen molecules are kicked out of the atmosphere by collisions with other molecules. Photo-ionisation, magnetic fields and fast atoms from the solar wind give an extra notch. Next the hydrogen molecules fly through space until they hit something cold enough or massive enough to keep a hold on them. PiusImpavidus (talk) 12:01, 15 June 2016 (UTC)[reply]

Minimum forward current for Infrared LED

My understanding is that there's no such thing as a minimum forward current for LEDs; that as long as the V_f of LED is met, the LED will operate in forward bias mode and emit light, however little of it. These pages seems to support this[7][8].

But I came across this part, QRE1113[9], where on page 5 of its datasheet， "Fig.6. Forward Current vs. Forward Voltage" seems to show the forward current, I_f, being cut off at 10 mA. Does that mean that this part won't operate with a I_f less than 10 mA? Or am I reading the graph somehow? Johnson&Johnson&Son (talk) 17:39, 14 June 2016 (UTC)[reply]

The datasheet is for a reflective object sensor that consists of a LED plus a phototransistor. The graph in Fig. 6 is simply incomplete and there is no reason to expect unusual behaviour at LED currents I_F below 10 mA. However the datasheet implies I_F = 20 mA is normal operation and the spread of forward voltage at that current (1.2V typical, 1.6V maximum) is much wider than the "typical" graph might suggest. Fig. 1 shows that the sensor can be used at I_F = 10 mA and it probably works at lower I_F but such operation is outside the range that the data sheet supports. AllBestFaith (talk) 22:40, 14 June 2016 (UTC)[reply]

Thanks!Johnson&Johnson&Son (talk) 02:09, 15 June 2016 (UTC)[reply]

Engineering - problem solving

Classically, engineering has been about solving problems in creative ways through the application of engineering principles, but have some engineering disciplines, other than in research, become more about following codes and paperwork? I believe in electronics, medical or automotive engineering, innovation and problem solving is still at the heart of engineering but is this still the case in infrastructure, buildings or building services and systems? 2A02:C7D:B965:6200:C4BA:9A78:DF03:CD7F (talk) 21:13, 14 June 2016 (UTC)[reply]

Adhering to codes, standards and legislation, and making written records, are found in all engineering disciplines; just as problem solving and creativity are found in all engineering disciplines. Different levels of both will be found in different projects and different workplaces but to suggest significant differences exist across whole engineering disciplines is too broad a generalisation to be worthy of serious consideration. Dolphin (t) 21:42, 14 June 2016 (UTC)[reply]

I certainly hope that following the relevant codes is a big part of medical and automotive engineering. I don't want my pacemaker or car brakes designed by some guy who just had a wacky new idea. CodeTalker (talk) 23:46, 14 June 2016 (UTC)[reply]

There's a big difference between the disciplines where prototypes are common, and those where the final products tend to be built direct from plans. In the latter case the engineer follows a fairly standardised way of designing a particular device. In the former, we have stringent sets of tests that must be passed, so the wacky idea has to prove it is robust and useful. I must admit neither of the answers above impress me overmuch, in terms of insight or accuracy. Greglocock (talk) 00:14, 15 June 2016 (UTC)[reply]

June 15

How do I initiate a discussion on a paper I've written explaining mass inertia?

I've written a paper that computes mass inertia. I'd like to discuss the paper with knowledgeable people who can point out any deficiencies in my thinking.

The last time I attempted this, I wound up "talking" to immature people with nothing but sex on their minds. I'd really like to discuss the subject with other adults.

I think I can explain mass inertia. Is anyone interested?

Zee99 Zee99 (talk) 00:09, 15 June 2016 (UTC)[reply]

Wikipedia is definitely not the correct place to challenge accepted science. The problem here is that LOADS of people "think" they've come up with a new theory in physics, it's actually a very common phenomenon, except that pretty much all of them are wrong, within a very small margin of error. They pretty much all have some fundamental misunderstanding of the existing accepted science, to a greater or lesser extent. I'm guessing you don't have a degree in physics, so I'm sorry if it sounds harsh but the overwhelming probability is that you just don't understand the current science well enough to challenge it, let alone "overturn" something that is already accepted by science. Here are two articles you should read, one from quroa and another from a famous physicist who's emailbox is literally inundated by people proposing "new theories", this is apparently a well known phenomenon for physicists who put themselves in the public sphere. The harsh truth is, there are no shortcuts, if you want to overthrow some existing science, no one is going to do it for you, YOU have to put in the years of study to figure out why your theory is wrong, and if you put in the years and the hard yards and the STILL think your theory is right, only then you might be in a position to start convincing other people. If you do really want to just go and talk to some proper physicists, register to attend a meeting of the American Physical Society. Vespine (talk) 04:17, 15 June 2016 (UTC)[reply]

Pretty much anyone can upload to arXiv, though from what I hear papers that don't have a "trusted" person to vouch for them get dumped into the "general" categories, which are pretty much the circular file for all the crank nonsense that gets submitted. What I would suggest is to contact a professor of physics. Be respectful and open to critique and there's a good chance they'll give you some attention, or refer you to someone who can. However I will echo what Vespine said. If you don't have a degree in the relevant fields, don't be at all surprised if your theory turns out to be flawed. Now this shouldn't be viewed as a mark against you. It's great that you're interested in science, and making mistakes is part of learning. But please don't go down the crank route of, when someone highly knowledgeable explains to you why you're wrong, deciding that you're right, everyone else is wrong, and all of science is a conspiracy against you. And hey, maybe you have figured something out, in which case you might be able to get your paper published and help advance scientific knowledge. --71.110.8.102 (talk) 08:47, 15 June 2016 (UTC)[reply]

Organic chemistry

hoffman bromide reaction mechanism — Preceding unsigned comment added by Tej Bogati (talk • contribs) 07:39, 15 June 2016 (UTC)[reply]

This, perhaps? Hofmann rearrangement - though if so, the word is bromamide, not bromide. Your question is very vague, and you really need to make it much clearer as to what you are actually asking. Wymspen (talk) 09:02, 15 June 2016 (UTC)[reply]

Adaptive value of mushroom toxins?

Today's featured article, on Amanita bisporigera, got me thinking about something I'd idly wondered about for a while.

Poisonous mushrooms seem to produce toxins that can be extremely complex molecules, and that affect megafauna in a wide variety of ways. Is this "on purpose", so to speak? Less anthropomorphically, do they get any selective advantage from it? It's a little hard to figure out how. I mean, I can certainly imagine that dying animals provide nutrients for fungi, but it takes quite a while before the animal dies; the benefit would seem to be shared with a whole lot of fungi that don't have the toxin. The Amanita ones interfere with RNA; could this be for some other "reason", with the bad effects on mammals being just a side effect? Intuitively that's hard to believe as well, but I suppose possible.

Similar questions for bacteria that produce extraordinarily toxic compounds — C. botulinum, C. tetani, Bacillus anthracis. Now with those, I really can't believe it's an accident — the molecules seem too specifically tailored to kill. I assume the first two kill animals that then provide an anaerobic growth medium for the bacteria, or some such. For anthrax, probably something similar, though it seems extraordinarily wasteful, given that most of the bacteria perish with the animal, and only a few that come out and sporify end up being able to infect other animals and pass on the genes. But nothing that I've read about them seems to address the question head-on. Has there been research specifically on this question? --Trovatore (talk) 09:25, 15 June 2016 (UTC)[reply]

Sure, the toxicity of Amanita spp. definitely seems to be "on purpose", insofar as it is widely regarded as an adaptive trait (i.e. one that confers a selective advantage, so I redirected that common phrase). It's not just toxic to megafauna, it's toxic to most eukaryotes. Here [10] is a paper that mentions that, but its primary purpose is examining the adaptations that allow fruit fly larvae to eat Amanita safely (That's why they work as fly traps, hence Fly agaric). Anyway, once you know the toxin defends the fruiting body from many/most potential enemies, then it's fairly easy to see that it has selective benefit, as those that are more toxic will tend release more spores than their less toxic siblings, etc.

For the Clostridium spp. I'm less sure. Honestly until just now I thought that tetanus was sort of a freak accident, but it's hard to say for sure. One thing is clear is that most Clostridium are not toxic to mammals, and even the toxin-generating ones are perfectly happy to do their thing in the soil and never get into an animal. Anyway, my guess/intuition may be wrong, so read these articles [11] [12] and refs therein to get to the bottom of it. One is about a interesting concept of "pathogenicity islands" in bacteria, and the other is "Genetic characteristics of toxigenic Clostridia and toxin gene evolution". They should have some comments on adaptive value of Clostridium toxins. SemanticMantis (talk) 14:57, 15 June 2016 (UTC)[reply]

Thanks, SM. I'll see if I can find some time and dig into them.

So your understanding is that the toxins in mushrooms are for defense rather than predation. That seems to have the same problem, though. The poison takes a long time to kick in, so the costs are concentrated and the benefits are shared with other fungi. Unless the animals learn to avoid the toxic ones, which they probably do, but often the toxic ones are hard to distinguish from the safe ones, which complicates the narrative.

When I read about how the bacterial toxins work, I can't believe it could possibly be an accident. There are just too many moving parts that have to work together. What advantage the bacterium gains from it still seems a bit obscure. --Trovatore (talk) 18:48, 15 June 2016 (UTC)[reply]

Yeah, maybe it's not an accident; I'm not so good at biochem, and I can't really judge an argument based on complexity or cost of synthesis. I do think some time with those papers will pay off though.

As for the shrooms- one thing to remember is that animals do learn. Not only within lifetime, but also as a selective process acting over generation, wherein things that eat smelly mushrooms die and don't have as many babies. That's why warning coloration works, right? It's not perfect and it doesn't help the odd poison arrow frog that does get eaten, but it's better than nothing , and it's good enough to independently evolve and persist across a wide range of clades, from plants to amphibians to mushrooms. And it's ok if the benefit is shared or if there are look-alikes too - see e.g. Batesian mimicry and Müllerian_mimicry, where aposematic cues can be shared among whole groups of organisms, many of which are fakers. There's limits to how many can fake it before the whole game is up, but that's getting far too lost in the details. One more ref: here [13] is a paper on olfactory aposematism that mentions Amanita's odor as being a deterrent to natural enemies. SemanticMantis (talk) 19:06, 15 June 2016 (UTC)[reply]

It might be relevant to bear in mind (as I'm sure you're well aware) that the mushrooms are not discrete organisms, but minor parts of a possibly extensive and long-lived subterranean mycelium which itself is not significantly damaged by individual fruiting bodies being eaten – this merely hampers its reproduction. Consequently, discouraging a particular animal from eating more of them (by noxiousness or toxicity) may well have a significant benefit for that particular mycelium. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 14:08, 16 June 2016 (UTC)[reply]

That is a very good point, thanks. SemanticMantis (talk) 16:06, 16 June 2016 (UTC)[reply]

The Bourne identity

Hi WP:RD/S people.
"Bourne" is the family authority for Flabellidae. See ITIS and WoRMS
Who is this Bourne? I did do my best to find out who this most probably notable zoologist may be. And I failed.
Turning it over to you all.--Shirt58 (talk) 13:44, 15 June 2016 (UTC)[reply]

A search for Bourne 1905 on Google Scholar finds "Report on the solitary corals collected by Prof. Herdman, at Ceylon, in 1902. by Bourne, G C." Searching for that or 'Flabellidae Herdman bourne' finds it's also mentioned here [14] [15] [16]. Notably [17] says "Published in Bourne, Gilbert C. 1905. Report on the solitary corals collected by Professor Herdman, at Ceylon, in 1902. In: Report to the government of Ceylon on the pearl oyster fisheries of the gulf of Manaar (Herdman, ed.), [Unspecified Publisher]: 187-242 + Pls. I-IV." Searching for 'bourne gilbert c ceylon' finds [18] and [19]] which mentions a Bourne, Gilbert Charles. Searching for that name finds Wikisource:Author:Gilbert Charles Bourne, Wikispecies:Gilbert Charles Bourne and [20]. Nil Einne (talk) 14:58, 15 June 2016 (UTC)[reply]

When do scientists predict we will have warp drive

When? 100 years from now? 200? 1000? When? — Preceding unsigned comment added by Uncle dan is home (talk • contribs) 18:26, 15 June 2016 (UTC)[reply]

Never. As best as anyone can tell such a thing is impossible. There are mathematical theories that allow such a thing, but they are math, not reality. The math may turn out to describe reality, or it may not, no one knows. See Alcubierre drive for more on this. Ariel. (talk) 18:36, 15 June 2016 (UTC)[reply]

Depends what you mean by "warp drive". If you mean some kind of magic engine that will accelerate your spaceship to a superluminal velocity, such a thing is impossible based on our current understanding of physics. There may be some (almost literal) loophole that lets you travel to distant locations by using a wormhole, but this is highly speculative and the technology required is far out of our reach. CodeTalker (talk) 19:39, 15 June 2016 (UTC)[reply]

As the article notes, the Alcubierre drive doesn't violate general relativity. This doesn't necessarily mean it's possible to construct one, but it's perfectly consistent with relativity. --71.110.8.102 (talk) 00:40, 16 June 2016 (UTC)[reply]

It's "consistent" with general relativity only inasmuch as you can take any differentiable spacetime manifold, plug it into the GR field equation, and get a stress-energy tensor. Finding a "solution" of this sort takes no effort; literally anything is a solution. In most cases, the stress-energy tensor bears no resemblance to anything that could arise from actual matter obeying physical laws. As soon as you add any physical constraint, by imposing one of the energy conditions for example, warp drives are excluded. For a longer rant on this subject, see my long post in this thread. -- BenRG (talk) 22:00, 16 June 2016 (UTC)[reply]

By warp drive, i mean ships that can warp space,creating a bubble that can travel faster than light. The spaceship itself doesn't move faster than light, it's the bubble that moves faster than light. — Preceding unsigned comment added by Uncle dan is home (talk • contribs) 21:44, 15 June 2016 (UTC)[reply]

Well, warp drive has a "Real-world theories and science" section... Dismas|^(talk) 00:30, 16 June 2016 (UTC)[reply]

Some scientists say "never". There's no reason to suppose a warp drive is necessarily possible. As noted, the Alcubierre drive has gotten a lot of attention, and is theoretically possible under general relativity, but there are a lot of problems that make many think it's not possible to actually construct one. It's quite possible constructing a warp drive is impossible, and we will always be limited by c. --71.110.8.102 (talk) 00:40, 16 June 2016 (UTC)[reply]

Your great great grand children may well be robots who can travel at the speed of light by uploading the information in their electronic brains via radio communications to some machine at a distant location. They probably won't bother attempting to build fancy spacecraft. Count Iblis (talk) 06:19, 16 June 2016 (UTC)[reply]

Household wiring

In a split-phase electric power system, is there an easy way to identify which outlets are line-to-line and which are line-to-ground (without having to rip up the drywall to examine the wiring itself)? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 21:24, 15 June 2016 (UTC)[reply]

Assuming you're in the USA, see NEMA connector. The 120 V sockets have vertical blades, the 240 V sockets have horizontal blades. Tevildo (talk) 21:51, 15 June 2016 (UTC)[reply]

I've checked out NEMA connector, and the table actually shows that some of the sockets can be used with either 120V or 240V (and look like 120V ones). In these cases, how can I tell for sure? Do I have to check them with a voltmeter, or is there an easier way?

2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 22:09, 15 June 2016 (UTC)[reply]

The NEMA-14 socket has four contacts (both phases, ground, and neutral), so can be used with both 120 V and 240 V appliances depending on the plug wiring; however, it'll always have both phases connected to it. There isn't a three-pole NEMA socket which can (legally) be connected either between phase and neutral or between phase and phase. If you're confident that you can use a voltmeter safely, that probably is the easiest way of checking any sockets you're not sure about. Tevildo (talk) 22:32, 15 June 2016 (UTC)[reply]

Just went down to the garage -- almost all of the sockets there are standard 5-15 120V type, but there's one which is different and is not one of the NEMA standard types -- it looks like a NEMA 10-30, but with an extra triangular hole in the center. And in the fuse box, there are 2 double-pole circuit breakers, one rated for 15 amps and the other for 30 amps -- the 30-amp one seems to correspond with the oddball socket and is labeled "Dryer", but the dryer is not plugged into the oddball socket but into one of the 120V ones along with the washer and the central vacuum. Is the oddball socket the 240-V one? (The other double-pole circuit breaker is labeled "Dishwasher" -- should I look for another non-standard socket under the kitchen counter?) 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 22:37, 15 June 2016 (UTC)[reply]

One of these? That's a 10-30R, the hole is to ensure the plug isn't inserted incorrectly. It will have (or, rather, should have) both phases and neutral, but no ground. Tevildo (talk) 23:11, 15 June 2016 (UTC)[reply]

Yes, exactly! So, the voltage would be 240V between the two diagonal slots, and 120V between either of these and the L-shaped one, right? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 23:21, 15 June 2016 (UTC)[reply]

Yes. See, for example, this article. Glad to be of assistance! Tevildo (talk) 23:46, 15 June 2016 (UTC)[reply]

Thanks! 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 00:39, 16 June 2016 (UTC)[reply]

Regarding the dishwasher... In our house (in Canada) in the kitchen there are split duplex outlets, where the upper and lower outlets are on opposite phases. These are wired to a double-pole breaker since live wires from two circuits are in the same electrical box behind the outlet. This arrangement lets us draw up to 15 A from the upper outlet and 15 A from the lower outlet simultaneously. However, the same 15 A, 120 V circuit feeding one half of one outlet also powers the dishwasher. So the dishwasher is supplied through a double-pole breaker even though it runs on the normal single-phase 120 V. Possibly you have the same arrangement. As to a socket, until recently all our dishwashers had screw connections and were directly wired into the circuit, but our newest one came with a standard plug and we therefore had a standard duplex socket installed inside the adjacent cupboard. --69.159.60.83 (talk) 09:35, 16 June 2016 (UTC)[reply]

Unless I've misunderstood you just measure the voltage. Ariel. (talk) 21:52, 15 June 2016 (UTC)[reply]

Assuming the OP is confident they can work safely with mains voltages. I would not encourage someone to stick things into electrical outlets unless they know what they're doing. If the OP has any doubt about their house wiring, they should contact an electrician (or their landlord). Tevildo (talk) 22:01, 15 June 2016 (UTC)[reply]

I'm shocked to hear that a clothes dryer runs from a 120 outlet.(Of course I have been shocked numerous times at circa 120 volts DC and AC). How many watts does the clothes dryer use? Edison (talk) 03:15, 16 June 2016 (UTC)[reply]

Berry punny. 120 V dryers do exist. It's fairly common for small apartment-sized units to run on 120 V. Shock Brigade Harvester Boris (talk) 03:53, 16 June 2016 (UTC)[reply]

Depends whether the dryer is heated by gas or electric. An old apartment of mine had one that was gas with 120V for timer and tumbling (and maybe gas ignition?). But behind it was an unused 240V/high-amps receptical because the landlord was planning to switch to all-electric instead of supplying gas. DMacks (talk) 18:14, 16 June 2016 (UTC)[reply]

Badgers and mushrooms

(Inspired by the above question re Amanita). In Phallus impudicus#Spore dispersal, there's a rather confusing sentence - "the proximity [of the fungi] to badger carcasses entices the flies to lay their eggs and help ensure that they are more quickly eliminated, removing a potential source of disease." I'm not sure what "they" refers to, and what is being protected from disease - the badgers, the flies, or the fungi? The causality also seems the wrong way round - I could understand if the argument was that the dead badgers attract the flies, and the flies encourage the fungi, but that's (apparently) not what the article says. Any help would be appreciated: I've also asked on the article talk page, but I'm sure the Science desk will be more responsive. Tevildo (talk) 21:36, 15 June 2016 (UTC)[reply]

Badger carcasses? We don't need no stinking badgers! (Sorry, I couldn't resist.) CodeTalker (talk) 22:09, 15 June 2016 (UTC) [reply]

Yeah, that's a mess. TLDR: "they" means "the badger carcasses", and who is protected from disease is the surviving members of the colony. I skimmed this paywalled ref [21]. It says "The benefit to badgers of this relationship is that the blowflies would rapidly and efficiently remove badger cadavers, which are potentially dangerous as disease reservoirs for the rest of the badger social group."

So it goes like this: all these shrooms attract flies. Shrooms near a badger sett attract flies that then also have a relatively high likelihood of finding a nice carcass in which to deposit eggs. Shrooms are fly laxative, and so flies poop after eating shrooms, and so a colony of shrooms can build up near a badger set. Badger setts that have shrooms nearby are then relatively more protected from disease, compared to setts that have no fungal associates. In this manner, shrooms, flies, and badgers all benefit from a positive reinforcement based on proximity.

Can you fix up the article from there? I can provide a pdf of the ref if anyone wants it. (BTW, some badger sets in EU have persisted for several centuries, perhaps longer. I recall something about old abbey records used to date a colony to a very surprising age. Anyway, this happy poop-death-fly-mushroom loop probably helps that long-term stability. Social insects are vigilant about casting out their own dead to keep the colony clean, but I don't think badgers have figured that out - and why bother, if some neighboring shrooms and flies will take care of it for you?) SemanticMantis (talk) 22:47, 15 June 2016 (UTC)[reply]

Thanks very much! Sleeman's text is sufficiently clear (although I still think the theory sounds a bit dubious, but that's not an issue here). I've made some appropriate changes to the article; of course, further improvements are always to be encouraged. Tevildo (talk) 23:30, 15 June 2016 (UTC)[reply]

June 16

FTIR

I've just seen a used FTIR machine on eBay for only $300, and it appears to be in good shape, but it has failed 2 of the self-tests -- the non-volatile RAM read and the +12V high-current test. My question is, will this machine be functional despite failing these self-tests? In other words, is it a bargain, or a waste of money? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 05:14, 16 June 2016 (UTC)[reply]

Well, the NV RAM means it won't remember settings when you switch it off, and may have to be recalibrated every time. The 12V problem is probably something to do with the IR side. If it's a good make buy it and strip it for spares. I see they have a working Nicolet for $750, if that is what you want Greglocock (talk) 08:58, 16 June 2016 (UTC)[reply]

Spares for what? I don't have an FTIR unit right now -- I'm just getting set up, and I need a not-too-expensive FTIR machine (I'm on a pretty tight budget right now) so that I could do my own quality control rather than having to send every specimen of my product to an outside lab for analysis (which costs money too). So whichever machine I buy will be my only one for the time being (at least until I get the crowd-funding done and start getting ready for full-scale production), and will be used for its primary purpose. So with all this in mind, do you think it will be better for me to buy the good machine for $750, the not-so-good one for $300, or just forget the whole thing and outsource the FTIR analysis to an outside lab? 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 09:33, 16 June 2016 (UTC)[reply]

It might work fine, or it might be worthless. If I already owned such a machine, I would try to run it against known standards and see how it performed. It might work okay. However, without more testing I doubt one could tell. Buying such a machine based solely on your description would be a gamble. If the seller has multiple machines, you could try asking them to show an analysis using the somewhat faulty machine and a fully functional machine and verify that they are similar. Personally though, I wouldn't buy any mission critical equipment with known faulty hardware. It's generally not worth the headaches and worry. Dragons flight (talk) 10:20, 16 June 2016 (UTC)[reply]

What about repairing the machine -- would it be worthwhile, or would it cost less to buy the fully functional machine? (Once again, the faulty machine costs $300 and the fully functional one costs $750.) 2601:646:A180:C88C:F88D:DE34:7772:8E5B (talk) 10:34, 16 June 2016 (UTC)[reply]

Note the Refdesk is for answering questions, not giving advice. There's no money back guarantee here if you are steered wrong. It would be more productive to ask and answer where manuals about these tests or other specifications might be found. Wnt (talk) 12:17, 16 June 2016 (UTC)[reply]

OK, let me put it another way: If I decide to buy the faulty FTIR machine and have it repaired, how much can I expect the repairs to cost me? 67.164.54.236 (talk) 01:28, 17 June 2016 (UTC)[reply]

There's an FTIR power supply on ebay for $410. Various suppliers have IR sources for also in the $400 vicinity. DMacks (talk) 03:28, 17 June 2016 (UTC)[reply]

Thanks! 67.164.54.236 (talk) 05:10, 17 June 2016 (UTC)[reply]

difference between web(unfinished?) version and published book

Hi I dont have access to following book: Metamorphic Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Metamorphic Rocks, ISBN-13: 978-0521336185.

I found "web version" on external link from 01/02/07. I am interested if there are differences between this version and published version on page 11, where use of ‘metamorphic/igneous’ ultramafic terms are discussed.

Thank you in advance Obradow (talk) 12:55, 16 June 2016 (UTC)[reply]

I'd be surprised if one of the relatively few of us happens to have that book handy to compare. But maybe I'll be surprised... May I ask what you intend to use this information for? Even if I were using this authority/ systematic convention for writing a serious scientific paper and naming rocks, I'd be comfortable using this pdf, and assuming it is either the same or better than the book. To be safe, I'd cite the pdf, not the book. The pdf and book both came out in the same year, and it is highly unlikely, in my opinion, that there are substantive differences. Sorry I can only offer opinion - since you're asking about one specific book it kind of limits our ability to give references! Also, I was not aware of SCMR, so thanks for the interesting question :) SemanticMantis (talk) 13:40, 16 June 2016 (UTC)[reply]

Lots of American university libraries own copies of this book (see [22]); if you'd asked this question two years ago, I would have been able to answer it easily. Nyttend (talk) 16:25, 16 June 2016 (UTC)[reply]

Lizard ID

Does anyone know what species this one is? He lives on top of a 500m hill near Bratislava, Slovakia. I was hoping that the black spot behind the head would be characteristic, but it seems that several of the European lizards have them. Thanks, Henry ^Flower 21:17, 16 June 2016 (UTC)[reply]

Might be Podarcis muralis. They are very common and widespread across Europe, so in that sense a parsimonious option as well. They come in lots of different morphs though, so you will see some examples that have rather different colors, though they will share other, more conserved morphological traits. Yours looks like this guy [23] to me. As for the dark spot: I'm not sure what you're referring to but if it's that depression on the side of the head, just in front of the neck, that's his ear [24]. SemanticMantis (talk) 22:30, 16 June 2016 (UTC)[reply]

June 17

How reliable are those DNA for discovering your ancestry?

Since a couple of years, I see ads for DNA tests that claim to draw your genealogical tree. They appear to be getting cheaper with time too. How reliable are their results? Can they really know that I'm 5% Inuit, 1% African, 14% North European and so on? — Preceding unsigned comment added by Hofhof (talk • contribs) 01:13, 17 June 2016 (UTC)[reply]

Genetic Ancestry Tests Mostly Hype, Scientists Say Shock Brigade Harvester Boris (talk) 01:23, 17 June 2016 (UTC)[reply]

You may have all those genetic traits, but on my initial examination, you are 82.7% knucklehead. Myles325a (talk) 05:18, 17 June 2016 (UTC)[reply]

@@ Line 274: / Line 274: @@
 Since a couple of years, I see ads for DNA tests that claim to draw your genealogical tree. They appear to be getting cheaper with time too. How reliable are their results? Can they really know that I'm 5% Inuit, 1% African, 14% North European and so on?  <small><span class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Hofhof|Hofhof]] ([[User talk:Hofhof|talk]] • [[Special:Contributions/Hofhof|contribs]]) 01:13, 17 June 2016 (UTC)</span></small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->
 :[http://www.livescience.com/7384-genetic-ancestry-tests-hype-scientists.html Genetic Ancestry Tests Mostly Hype, Scientists Say] [[User:Shock Brigade Harvester Boris|Shock Brigade Harvester Boris]] ([[User talk:Shock Brigade Harvester Boris|talk]]) 01:23, 17 June 2016 (UTC)
+:You may have all those genetic traits, but on my initial examination, you are 82.7% knucklehead. [[User:Myles325a|Myles325a]] ([[User talk:Myles325a|talk]]) 05:18, 17 June 2016 (UTC)