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April 29

How can a universe have properties as a whole, how can it live in a time realm not of its own making?

I miss (in the Big bang lemma) a discussion about the following problem:

A universe only can be said to expand if it has a finite inside dimension –which in increases in time.

Not to mention that Big Bang cosmology in speaking about its age, asserts that the universe lives in a time realm not of its own making, doesn’t a (finite) inside dimension imply a finite outside size –even though it obviously cannot be measured from the outside as space and time, the meter and second aren’t defined outside of it?

Put differently, what is the significance of statements about the size and age of the universe if by definition there is nothing outside of it with respect to which its size and age matters, physically?

Can someone explain how a universe can have particular properties and evolve as a whole if there is nothing outside of it with respect to which it can have properties, can interact with and express such properties? Antonquery (talk) 00:25, 29 April 2014 (UTC)

You've got a false premise there: the measurement of the size and age of the universe does not imply the existence of any exterior thing relative to which that measurement must be made. All the measurements are made with respect to things inside the universe that are - of necessity - younger and smaller than it. When we say the universe is 13.7 million years old, we do not mean that anything at all happened or existed 14 million years ago - we just mean that the universe has existed a bit more than two and a half times as long as the earth has. And the expansion of the universe means that we can determine that all objects were closer together long ago. It doesn't mean there's a space they've expanded into, and it doesn't mean there's a centre they've expanded from. AlexTiefling (talk) 00:34, 29 April 2014 (UTC)

Psst... billion, not million, right? ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:15, 29 April 2014 (UTC)

A million years here, a million years there, pretty soon you're talking about a real long time. —Tamfang (talk) 03:42, 29 April 2014 (UTC)

Ehh, what's a factor of a thousand between colleagues? AlexTiefling (talk) 11:32, 29 April 2014 (UTC)

The OP calls the Big Bang theory a lemma which is a philosophical statement that one accepts as true in order to find out whether another statement is true. This rightly characterizes the theory as a hypothetical model that strives to put an explanation to our observation that the universe is expanding. The idea began with Edwin Hubble's observation that all distant galaxies and clusters have an apparent velocity directly away from our vantage point: the farther away, the higher the apparent velocity, regardless of direction. Assuming that we are not at the center of a giant explosion, it must seem that all observable regions of the universe are receding from each other. Big Bang theory proposes that it has "always" been doing that, where the quotes show that such a simplistic assumption creates the paradox that everything originated from an abstract singular point. The implication is that if one could rewind in time our view of the universe and see it shrink, its outer border would come into view. For the moment, the popularity of the Big Bang model relies on Albert Einstein's general relativity and on simplifying assumptions such as homogeneity and isotropy of space. Since Copernicus, scientific thought has insisted that Earth is not in a central, specially favored position in the universe nor that humans are privileged observers of the universe. Thus we can do no more than theorize about what limits might exist, or existence itself, beyond our particular Cosmological horizon as in the OP's question about the Size of the universe. 84.209.89.214 (talk) 11:26, 29 April 2014 (UTC)

Lemma can also denote a headword in a dictionary or something similar. That's how the OP was using it—as a (somewhat confusing) way of saying "the article with 'Big Bang' as its title", not to refer to "a philosophical statement that one accepts as true in order to find out whether another statement is true". Deor (talk)

• I'd just like to add a pointer to Mach's principle, which is relevant to this discussion even if it doesn't apply directly. Looie496 (talk) 14:36, 29 April 2014 (UTC)

Is it true that eating burned food is not good for you?

^Topic ScienceApe (talk) 00:54, 29 April 2014 (UTC)

Shonuff. --Jayron32 01:39, 29 April 2014 (UTC)

For refs on WP, see Cooking#Cooking_and_carcinogens, and Heterocyclic_amine_formation_in_meat. SemanticMantis (talk) 13:10, 29 April 2014 (UTC)

From an Epicurean standpoint, it's terrible waste. Even if it doesn't kill you, you're never really "living" on char. InedibleHulk (talk) 00:20, May 4, 2014 (UTC)

Well, there you have it. After 20 years of people yammering at us to cook our meat until it's brown and flavorless to avoid E. coli, now they're turning around and snickering at us and saying ha, we gave you cancer. People should reject newfangled and dangerous inventions like partial dehydrogenation, but when it comes to an ancient practice like cooking, or which foods you choose to eat, a few thousand years of modern-era evolution of both genes and culture should give us some confidence that no matter what you do, you'll face a certain small risk of death. Wnt (talk) 04:43, 5 May 2014 (UTC)

Hand Meyer and Ernest Overton in Lund

Greetings. A photo of Hans Meyer and Ernest Overton taken in Lund, Sweden between 1907 and 1911 exists on Wiki. I have seen it twice but cannot find it again. Any suggestions? I have looked on wikis in various languages but I can' locate the page with that photo. — Preceding unsigned comment added by 2602:30A:C08C:F440:0:0:0:41 (talk) 01:42, 29 April 2014 (UTC)

Milk gone off but doesn't smell bad?

Is it possible for milk to curdle without smelling bad? I just poured milk on my cereal and it was all nasty and lumpy but there was no smell. Is that possible naturally or is my housemate trying to kill me? --78.148.106.196 (talk) 07:47, 29 April 2014 (UTC)

Sure it's possible naturally -- that's how they make cheese! As for smelling bad, that has to do with milk going sour, which is a different process altogether. 24.5.122.13 (talk) 10:15, 29 April 2014 (UTC)

That curdling is caused by growth of bacteria in the milk. The bacteria produce acids, and the acids cause the milk to curdle. You can also cause milk to curdle by adding acid directly, for example lemon juice or vinegar. Whether the curdling is harmful depends on what type of bacteria are growing. If they are the same types used to produce buttermilk or yogurt, then the milk can be perfectly healthy and good-tasting even after it curdles. But other types of bacteria will make it nasty-smelling and harmful. Looie496 (talk) 14:27, 29 April 2014 (UTC)

So what happened to my milk? Did I throw away some good cheese? I've never had milk go lumpy and not stink before. --129.215.47.59 (talk) 20:00, 29 April 2014 (UTC) (formerly known as 78.148.106.196 (talk)

It's probable that you could have made good cheese from your lumpy milk, but commercial cheese is made using rennet and a cultured bacterial mix (so that they know the bacteria are harmless). I think I would have thrown it away as you did, just in case there were some nasties amongst the bacterial mix that came from the environment. Dbfirs 21:20, 29 April 2014 (UTC)

If you drained most of the whey from your curdled milk, and scrambled up what is left, you would have cottage cheese. Looie496 (talk) 01:31, 30 April 2014 (UTC)

Fast walking in the heat

Do people with good levels of fitness not sweat or feel out of breath after walking fast in hot weather? 194.66.246.11 (talk) 11:26, 29 April 2014 (UTC)

For sweat, it seems to be the opposite of what you suggest. Here are two sources that say that people who are fit will start to sweat sooner, and more easily [1] [2]. No comment there on "out of breath". As for heat, note that humans change when living in different environments, see Acclimatization#Humans, and here [3]. Basically, people who spend more time in heat and exercise at higher heat respond differently than people who are not used to it. SemanticMantis (talk) 13:07, 29 April 2014 (UTC)

People with good aerobic fitness are less likely to feel out of breath in almost any situation. Regarding sweating, that's more directly a function of weight than aerobic fitness. Light people have a higher ratio of body surface to body mass than heavy people, so they don't need to sweat as much to stay cool. However, there is an additional factor: people who have gotten used to exercising in hot weather are less likely to notice that they are sweating than people who are not adapted to it. Looie496 (talk) 14:32, 29 April 2014 (UTC)

I'm sure your first sentence is right, but it's a rather tricky think to find a WP:RS to cite, isn't it? If anyone has one, please add. As for the weight, that is surely a big factor as well. My (admittedly not great) links above indicate that for two people of the same weight, the more aerobically fit one will sweat more during the same exercise conditions. SemanticMantis (talk) 14:41, 29 April 2014 (UTC)

Are been, a telephone links had been a powerful electric volts

Is it been, a powerful electric volts are beening in a telephone links, because a some transformation of a powerful electric volts always had been saved a incoming amplitude frequency of a powerful electric volts after a transaction of it?--Alex Sazonov (talk) 12:11, 29 April 2014 (UTC)

Landline covers the technical aspects of over-wire telephone service. I think that's what you are asking about. --Jayron32 13:11, 29 April 2014 (UTC)

Thanks for you. Is it been, a nets of these telephone links which I’m asked may been doing a level of logical as a level of logical of a nets of a computers?--Alex Sazonov (talk) 13:50, 29 April 2014 (UTC)

There are very complicated switches in a telephone network. See Public_switched_telephone_network and Switching_center#Technologies. There are indeed some analogies to the logic gates that form the basis of computer processing. There are similarities, but they are not the same thing. (I hope that helps. I understand English is not your native language, but you will get better answers here if you can spend a little more time going over your wording.) SemanticMantis (talk) 14:36, 29 April 2014 (UTC)

A Plain_old_telephone_service uses a nominal 48 volts. "The subscriber loop typically represents an electrical load of about 300 ohms, and does not pose a threat of electrocution to humans, although shorting the loop may be felt as an unpleasant sensation." Modern networking equipment like Router_(computing) are designed to work with these voltages. 196.214.78.114 (talk) 14:12, 29 April 2014 (UTC)

Thanks for all in our discussion. I been thinking that a logically level of a telephone links of a telephone nets of a powerful electric volts always must been doing as a more much logically level of a telephone links than a simple logically level of a telephone nets of a computers in the USA, thats it they always been be bestly.--Alex Sazonov (talk) 15:19, 29 April 2014 (UTC)

The Russian Wikipedia article on the Telephone may help. 84.209.89.214 (talk) 16:15, 29 April 2014 (UTC)

Thanks welly. Did a computers nets of a telephone links always been use a electrical telephone transformation of a electric telephone signals?--Alex Sazonov (talk) 16:38, 29 April 2014 (UTC)

Alex, perhaps you want an explanation of the differences between analog communication originally used in telephone links and digital signals used in data networks and inside computers. Please say what is your own language and someone will find a reference for you to read. 84.209.89.214 (talk) 18:56, 29 April 2014 (UTC)

Thanks. My native language is been Russian, but ofcourse I see that a electrical transformation in telephone links always is been own, but is been not another.--Alex Sazonov (talk) 19:25, 29 April 2014 (UTC)

Is it been, a telephone electronics always been use a powerful electric volts in a long telephone trunk line of a telephone links?--Alex Sazonov (talk) 06:53, 30 April 2014 (UTC)

The high voltage (48v) was needed in the old days to transmit signals reliably over miles of copper wire. Modern computer systems usually run on a much lower voltage, but there are still lots of older telephones connected with miles of copper, so the high voltage is still kept. Dbfirs 07:32, 30 April 2014 (UTC)

Thanks. But I always been mean in our discussion a 220-380 Volts of a powerful electric in a long telephone trunk line of a telephone links or a 550-580 Volts of a powerful electric in a old long telephone trunk line of a telephone links.--Alex Sazonov (talk) 09:33, 30 April 2014 (UTC)

No one except perhaps the poseur Antonio Meucci ever proposed using high voltage for a telephone. (By the way if you use Google translate the English will probably be far more intelligible than the word salad you have been posting here. It generally makes no sense at all and people try to figure out what you mean based on a word here and there.) Edison (talk) 14:32, 30 April 2014 (UTC)

Is it been, a tone of a voice speaking by a telephone links of a powerful electric volts been modify from a electrical telephone transformation?--Alex Sazonov (talk) 14:17, 30 April 2014 (UTC)

Why in the USSR always been make a telephone links of a powerful amplitude frequency of a signals but in the USA always been make a telephone links of a none powerful amplitude frequency of a signals?--Alex Sazonov (talk) 14:46, 30 April 2014 (UTC)

The Tsarist government of Russia issued its first decree on the development of urban telephone networks in 1881 and the first exchanges in the Empire opened the following year. Telephones played a significant role during the upheavals of 1917. According to the last tsarist Chief of Police, 'neither the military authorities nor the mutineers thought of occupying the Telephone Exchange'; consequently it continued to function, serving both sides, until the operators finally left their positions amidst the growing confusion'. In 1919, Sovnarkom nationalized all telephone systems in the Russian Republic. Until the end of the USSR in 1991, the sole fixed-line telephone operator in the country was the Ministry of Communications of the USSR. Today Russian landline telephony employs modern network elements such as digital telephone exchanges, mobile switching centres, media gateways and signalling gateways at the core, interconnected by a wide variety of transmission systems using fibre-optics or Microwave radio relay networks. Our article reports that services are still outdated in rural areas but says nothing about unusual high line voltages that could only create problems for Telephone exchanges. 84.209.89.214 (talk) 16:30, 30 April 2014 (UTC)

I been very thanks for yours explain of a history of the Russian telephone links, and as I been know a telephone links of the USSR always made as a powerful aggregation of a electric volts.--Alex Sazonov (talk) 18:17, 30 April 2014 (UTC)

Could anyone say me is been a multiplier of a amplitude frequency in a powerful electric volts?--Alex Sazonov (talk) 18:20, 30 April 2014 (UTC)

Ваш английский язык является недостаточным. Пожалуйста, попросите еще раз в русском языке. 84.209.89.214 (talk) 19:07, 30 April 2014 (UTC)

(A Google translation of the above is:"Your English is inadequate. Please ask again in the Russian language.") Edison (talk) 01:34, 1 May 2014 (UTC)

Well. Может ли кто-нибудь сказать мне, существует ли умножение (шаг) амплитудной частоты в силовых электросетях?--Alex Sazonov (talk) 20:22, 30 April 2014 (UTC)

Нет -- частота переменного тока не меняется при трансформации. 24.5.122.13 (talk) 19:47, 3 May 2014 (UTC)

A everyone new electric transformer in a nets of a electrical including always been done a new amplitude frequency of a electric volts, because a everyone new electric transformer in a nets of a electrical including always been done a new electric potential of a electric transformation.--Alex Sazonov (talk) 20:11, 4 May 2014 (UTC)

First of all, amplitude and frequency are two different things; second of all, in a power grid all power sources have the same frequency and are synchronized in phase -- so if the power generators output their current at 60 hertz (as they do in my country), then it will be the same 60 hertz everywhere without any kind of modulation; third of all, the transformers feeding power into the grid are also standardized in output voltage, so if the grid is designed for 500 kilovolts (a typical voltage for the US national power grid), then all the transformers feeding into it will output 500 kilovolts (plus or minus a few percent) -- this is EXTREMELY IMPORTANT because (1) many consumers of electricity depend on getting their power at a constant voltage, which in turn depends on maintaining a constant voltage in every power line, and (2) a transformer which outputs at a lower voltage than the others could allow the higher-voltage electricity in the power line (as much as 500,000 volts, remember?) to "backfeed" into the transformer and the upstream power generator, with consequences you would not want to contemplate. Am I making myself clear here? 24.5.122.13 (talk) 18:22, 5 May 2014 (UTC)

Unfortunately the Russian version makes no more sense than the English one. 84.209.89.214 (talk) 20:47, 30 April 2014 (UTC)

Excellent. InedibleHulk (talk) 21:10, April 30, 2014 (UTC)

A Google translation of Alex Sazonov's Russian text is "Well. Can anyone tell me if there is a multiplication (step) amplitude frequency power electric? " Gibberish? Edison (talk) 01:34, 1 May 2014 (UTC)

What a sense always is been mean a contours of a electrical transformation? Same it, in a Russian - Какое значение всегда имеют контуры трансформации электрического тока?--Alex Sazonov (talk) 08:01, 1 May 2014 (UTC)

Is it been, a ways of a electrical including for a electric transformer are been a contours of a electrical transformation? Same it, in a Russian – Являются ли способы включения трансформатора в электрическую сеть контурами трансформации электрического тока?--Alex Sazonov (talk) 18:38, 1 May 2014 (UTC)

Чо? 24.5.122.13 (talk) 19:48, 3 May 2014 (UTC)

point particle

do elementary particles warp empty space the same way that black holes do? I am imagining two very similar objects with one of their properties in common being "has no empty space 'inside'"?66.87.116.12 (talk) 13:56, 29 April 2014 (UTC)

All particles that have mass have gravitational fields. Albert Einstein predicted that gravity is due to curvature of the space around masses. In 1919 Arthur_Stanley_Eddington made the first empirical test of Einstein's theory by measuring the deflection of star lights by the sun's gravitational field. However the gravitational attraction between ordinary masses does not accelerate them beyond the speed of light, as occurs entering a black hole. 84.209.89.214 (talk) 15:30, 29 April 2014 (UTC)

Is that just for rest mass, or do those objects with only relativistic mass also warp space ? StuRat (talk) 16:23, 29 April 2014 (UTC)

Yes, also. Whenever the stress–energy tensor is nonzero, the geometry of space will be affected according to the Einstein field equations. I have seen a paper on exact solutions for the case of an intense electromagnetic field propagating through otherwise empty space. —Quondum 17:01, 29 April 2014 (UTC)

You can also see that this must be the case without invoking the intricate details of general relativity. Just consider the fact that a big mass like the Sun will bend light. So, a photon with some initial momentum will after passing close to the Sun hend up having a different momentum (it will have changed in direction). Since total momentum must be conserved, this means that the Sun must have changed its momentum to compensate for the change in the momentum of the photon. Therefore the photon must have a gravitational field. Using just the formula for the bending angle, you can easily compute the effective gravitational potential of a beam of light. Count Iblis (talk) 17:05, 29 April 2014 (UTC)

because the infinity grab in small scal , because the secend degre of R , it sqewez to a point flip the derection of time and mulltiply by three , and make the three visibel dimention space . Thanks water — Preceding unsigned comment added by 192.116.142.154 (talk) 13:42, 30 April 2014 (UTC)

Well that explains everything. Justin15w (talk) 15:19, 30 April 2014 (UTC)

Thanks, water. Thwater. AlexTiefling (talk) 15:42, 30 April 2014 (UTC)

The classical idea of a black hole does have empty space inside. An event horizon marks a point of return, but is supposed to have nothing locally special visible to someone falling in. Everything gets crushed in a singularity at the center. However, the fuzzball idea does suppose the hole is packed with string theory objects. A particle, by contrast, has a much more poorly defined position (Compton radius) and contains a space within that radius that may be shared with other particles. (See Bose-Einstein condensate, for example) Wnt (talk) 19:35, 30 April 2014 (UTC)

Alien Worlds???...

Do any Biologist or Biochemist know what are the problems for Humans when they find in the Future a Planet with Life???...

First Question: WHAT must be right to be a Planet with Life Human-friendly???...

Second Question: WHAT must be wrong to be a Planet with Life Human-enemy???...("a forbidden Paradise!!!...")

Third Question: Could it be a Si₁₄-World in place of our C₆-World???!!!...

THANK you VERY-VERY much!!!...

"Have a nice Day/Night!!!..."

SPYROU Kosta - Greece - Honeycomp (talk) 14:56, 29 April 2014 (UTC)

As a minimum for life as we understand it, a planet should be in the habitable zone; planets outside it are automatically unfriendly to Earth-based life forms. But beyond that, a lot is speculation - there are so many ways a planet's biome could be harmful to humans, it's hard to know where to start - huge predators, virus- or bacteria-like pathogens, poisonous creatures, all life existing in places (glacial trenches, volcano margins) that are naturally bad for humans... AlexTiefling (talk) 15:03, 29 April 2014 (UTC)

You might also want to read up on planetary habitability.--Shantavira|^{feed me} 15:30, 29 April 2014 (UTC)

All scientists, not just bio-scientists, know that an eventual discovery of an extraterrestrial planet with life will force a review of everything we know about our own origins. — Preceding unsigned comment added by 84.209.89.214 (talk) 16:16, 29 April 2014 (UTC)

That's very dubious. Suppose that 10 years from now, someone takes the spectrum of an Earth-like planet and sees oxygen and methane--a very strong indicator of life. How would that force a review of the African origin of humans, of early conditions on Earth, or of any of the geological record? Suppose that tomorrow, someone discovers a radio signal from an exoplanet that's undeniably artificial. How does that force a review of evolutionary history? Of course discovering life on other planets could radically change everyone's philosophical outlook, but it might have little effect on existing science. --Bowlhover (talk) 16:52, 29 April 2014 (UTC)

If the philosophy of science were already perfected beyond criticism, there would be no need for the many science fiction writers who have addressed the implications of contact with alien beings. Now on Earth we cannot isolate the scientific hypotheses that we test from the influence of the theories in which our observations are grounded (see Kuhn). Therefore, if someone communicates by radio or other means with life on another planet, they should listen in order to learn, rather than reiterate their favourite theory-laden observations that are circumscribed by their own theoretical presuppositions. 84.209.89.214 (talk) 15:36, 30 April 2014 (UTC)

First Question: The Rare Earth Hypothesis uses the Goldilocks principle in the argument that a planet must neither be too far away from, nor too close to a star and galactic center to support life, while either extreme would result in a planet incapable of supporting life. It considers the likelihood that something we recognize as life might have evolved on a yet unknown planet; however the probability can be greater if we envisage possible Extremophile life forms, and much less probable that we ever find another "human friendly" planet. The prospect of Terraforming a planet to this end has arisen in science fiction.

Second Question: The more human friendly a planet with life turns out to be, the more likely it is to have predators or parasites that will like to dine on humans, and on Earth our experience has shown unfortunate results for a civilisation that contacts a more advanced one.

Third Question: This calls for speculation. 84.209.89.214 (talk) 16:00, 29 April 2014 (UTC)

Two comments:

A) Habitable zone is defined as distance from a star, but a large planet might provide enough tidal heating to keep a moon warm. So, the habitable zone around a star can be extended outward for some moons around large planets.

B) Conditions needed for life to begin might be considerable different from those needed for humans to exist there now. The early Earth would have been quite inhospitable to humans, due to lack of atmospheric oxygen, toxic gases in the air, high volcanism and meteor impacts, and obviously a lack of plants and animals to eat. However, using modern technology, we might be able to live in places not well suited to primitive humans. StuRat (talk) 16:20, 29 April 2014 (UTC)

It occurs to me that question three, i.e. whether it's possible, could be answered by someone smarter than me (which is most of you) looking at what it is that makes Carbon so special as the "anchor" of organic life as we know it. That is, does Silicon have the potential to interact with other elements in pretty much the same way that Carbon does? One possible side issue: The basic organic compounds often include elements with low atomic numbers. Do scientists believe that the larger atomic numbers were created later? That is, would Silicon have turned up well after Carbon, and if so, could primitive life forms or almost-life forms have already gotten started before Silicon came along? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:21, 29 April 2014 (UTC)

The thing that makes carbon "special" is the ability to form long-chain and complex structures. Silicon can also form chains, but nowhere near as long as carbon can. --Carnildo (talk) 01:43, 30 April 2014 (UTC)

Another element substitution I asked about here some time ago is substituting F for O (Wikipedia:Reference_desk/Archives/Science/2013_October_10#Fluorine_planet). Granted, it's not very plausible, given the relative abundances of these elements.

Hypothetical types of biochemistry gives many more substitutions. Possible substitutions for C include B, Si (this is the one you are proposing), P, S, and metal oxides. O₂ could be substituted by Cl₂ (and maybe F₂? That's the one I asked about.). P could be substituted by As. H₂O could be substituted by NH₃, HF (the one I asked about), CH₄, H₂S, HCl, H₂SO₄, HCONH₂, CH₃OH, N₂ (l), H₂ (l), a mix of H₂O and H₂O₂, etc. Double sharp (talk) 16:14, 3 May 2014 (UTC)

Hmmm, a fun one ought to be to substitute carbon with boron nitride, which apparently allows for analogs of things as complex as naphthalene and biphenyl. [4] Wnt (talk) 05:16, 4 May 2014 (UTC)

@Honeycomp:: See especially this book for your third question: Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, by Robert A. Freitas Jr. You want section 8.2.3 (and for substitutions in biochemistry in general, the whole of chapter 8). @Wnt:: Boron nitride might be slightly problematic, though it is a beautiful parallel to carbon: according to Xenology, "While some B-N polymers are known to be stable to high temperatures, many such substances turn out to be less stable with heat. Borazine, the boron-nitrogen analogue to benzene, is more susceptible to chemical attack because of its greater reactivity. The presence of water tends to degrade most B-N polymeric compounds." Double sharp (talk) 13:14, 5 May 2014 (UTC)

The high temperature degradation might not be a problem, on a planet where temperatures are more stable than on Earth. On Earth, temperatures are more stable in the ocean, so a planet without any land should have a more even temperature, as it's more able to distribute heat by convection. The ocean need not be water, as any liquid can do the same thing. Similarly, a thick atmosphere, like on Venus, can distribute heat more evenly, although you'd want it to be farther from the Sun to avoid the entire planet getting too hot, as on Venus, due to the greenhouse effect. A short day would also help to keep the daylight heating/nighttime cooling cycle to a minimum, while a lack of tilt would prevent the summer/winter cycle. Tidal heating, say of a moon around a large planet, should also provide more evenly distributed heat, rather than just on the surface, as sunlight does. StuRat (talk) 14:18, 5 May 2014 (UTC)

Alien Earth-like World...

SORRY but I made the FALSE Question earlier...

Imagine that we find a Planet with Earth-like life:

1). with Atmosphere like ours...

2). with water H2O...

My Questions are Biology-Questions:

If the D.N.A. is like ours - or NOT...

If the Amino-Acids are like ours - or NOT...

If the Molecules of Life have the same Hirality - or NOT...

a). WHAT of them will be Human-friendly???...

b). WHAT of them will be Human-enemy???...

THANK you VERY-VERY much!!!...

"Have a nice Day/Night!!!..."

SPYROU Kosta - Greece - Honeycomp (talk) 17:38, 29 April 2014 (UTC)

• You may find the Wikipedia articles titled Extraterrestrial life and Astrobiology useful to start your research. --Jayron32 17:42, 29 April 2014 (UTC)

• You mean chirality, which might well be reversed. Also, some evolutionary "mistakes", like the one that causes our blind spot, might not be repeated. And if bipedal locomotion developed earlier there, they might have evolved a spine that actually works properly when walking upright, unlike ours which is prone to all sorts of problems (I think a thick, rubbery spinal cord with no nerves would make sense inside the spine, with the nerves in front of the spine, in a notochord.) StuRat (talk) 18:25, 29 April 2014 (UTC)

There is some evidence that amino acids (Urey-Miller experiment), RNA (RNA world), and metabolism ([5]) date back to the origin of life, or before the origin of life. The solution our cells contain is closely based on the primordial sea. If this is true, then many characteristics of modern Earth life may be very similar to the environment of the early Earth, and the biochemistry of Earth life should not be seen as an evolved optimum. Nonetheless, some important evolution has occurred, most notably the oxygen catastrophe that replaced the primordial reducing atmosphere with a highly oxidizing environment. The presence of oxygen continues to be stressful to life to this day - the activity of genes like superoxide dismutase appears to be important in trying to stave off a process of aging that is partially due to reactive oxygen species. And yet, of course, we now cannot do without oxygen, nor can we tolerate ammonia. To answer your question, you would need to know how many planets have something like Earth's early chemistry, and whether other life is more prone to evolve away from its original biochemistry, but we don't know either of these things. Wnt (talk) 11:35, 30 April 2014 (UTC)

SPYROU Kosta: My Questions are specific!!!:

Same D.N.A. = Human-friendly Or Human-hostile???...

Same Aminoacids = Human-friendly Or Human-hostile???...

Same Chirality = Human-friendly Or Human-hostile???...

THANK you... - Honeycomp (talk) 14:09, 1 May 2014 (UTC)

"Human-friendly" or hostile could mean a vast range of things:

1) Can they cause bacterial or viral diseases in humans ? Here more similar life forms are more likely to causes diseases, although prions are an interesting exception.

2) Could they hunt humans ? Here a very different biology might not prevent them from hunting humans. Even if they can't digest us, they might kill us anyway, not knowing that.

3) Warfare involving intelligent aliens ? Here I wouldn't think biological similarity would make much difference, although they might tend to sympathize more with similar life forms. Here on Earth, for example, you will got a lot more donations to save the chimps than to save the centipedes.

However, a very different life form might not even perceive us as alive, or interact with us in any way. For example, perhaps crystals are alive, and grow and reproduce over millions of years, never knowing there is any other form of life. StuRat (talk) 15:50, 2 May 2014 (UTC)

SPYROU Kosta: THANK you StuRat for your Help!!!... - Honeycomp (talk) 00:01, 4 May 2014 (UTC)

You're quite welcome. StuRat (talk) 16:17, 4 May 2014 (UTC)

Math. function

Hi, What function gives 1,7,13,25,49,97,... It begin's with (6+1) then (2*6+1) and (2*12+1) to infinity. It's for Flower of life article. Thx --YB ^✍ 20:42, 29 April 2014 (UTC)

1 + (2^x * 6)

- Eron^Talk 20:58, 29 April 2014 (UTC)

Simple indeed. What if it start at one? --YB ^✍ 21:09, 29 April 2014 (UTC)

The 1 simply doesn't follow your rule; it ought to be (3+1) so that the next term can be (2*3+1). --Tardis (talk) 00:45, 1 May 2014 (UTC)

It might not make that much sense to you, but that sequence has an official name in the OEIS, you can cite this page [6] if/when you add it to the article. SemanticMantis (talk) 21:27, 29 April 2014 (UTC)

I had the feeling it had something to do with Fibonacci number and fractals. Thanks for the ref. --YB ^✍ 23:15, 29 April 2014 (UTC)

That's not the same sequence; they diverge after 769 ($x=7$). (Similarly, the 2, 3, 5 part of the standard Fibonacci sequence matches $1+2^{n}$ for n 0, 1, and 2, but not afterwards.) --Tardis (talk) 00:45, 1 May 2014 (UTC)

Why didn't you post this to the Math Desk ? StuRat (talk) 03:39, 30 April 2014 (UTC)

I haven't examined the connection to Flower of Life but the natural thing would be to include 3+1 = 4 so it goes 1, 4, 7, 13, 25, 49, 97. That's OEIS:A004119: 3×2ⁿ+1. A Thabit number is 3×2ⁿ−1. PrimeHunter (talk) 17:25, 1 May 2014 (UTC)

Sorry, the sequence is 1,7,19,37,61,... [7]. Anyway, thanks for the link. --YB ^✍ 01:33, 2 May 2014 (UTC)

Then I guess you want Centered hexagonal number which already has a see also link to Flower of Life. PrimeHunter (talk) 00:24, 4 May 2014 (UTC)

April 30

Any sources on skin allergies/reactions to vinyl ?

...either inside Wikipedia or outside ? I Googled, but didn't have much luck. StuRat (talk) 03:41, 30 April 2014 (UTC)

@StuRat: [8] (section Vinyl Gloves and Allergic Reactions) may have what you are looking for. Zhaofeng Li [talk... contribs...] 10:29, 30 April 2014 (UTC)

This paper has some info [9]. A key search term is contact dermatitis. SemanticMantis (talk) 15:16, 30 April 2014 (UTC)

Thanks so far. Any more info ? StuRat (talk) 14:07, 1 May 2014 (UTC)

Overtraining

This isn't a request for advice, more of a curiosity. Looking at various sources around the web, I've seen all sorts of recommendations on how long you should wait between exercising - some vague, some very specific. At any rate, most of what I've seen seems somewhat contradictory - some sources claiming that exercising every other day can be counterproductive and that you should only exercise twice a week, other sources claiming that you can exercise every day, etc. Most places do not go into any detail about what counts as "exercise" either - obviously an intense session at a gym using your whole body is going to be different that doing some pushups and situps between commercials. So, I wanted to know, if there were any studies that go into greater detail, or if anyone could give a good explanation of what exactly causes overtraining/what exactly it is. --Again, I'm not looking for medical advice, I haven't been to a gym in years, I just stumbled into the topic and find it rather odd and confusing. Thank you for any assistance:-)Phoenixia1177 (talk) 08:11, 30 April 2014 (UTC)

Basically exercise works by damaging the body, which then needs to be repaired. Where the damage occurs, more muscle cells, blood vessels, etc., are added during the healing process, to prevent future damage when repeating the same exercise. The body will obviously take some time to heal, but how long it takes varies by the amount of damage and other conditions, and also varies by individual. Here focusing on a different part of the body each time a person exercises will help give the previous target more time to heal. If the person's body is sore when they start exercise, then they should probably avoid exercising in that area, so they don't damage it further, until it has time to repair. StuRat (talk) 11:29, 30 April 2014 (UTC)

• It partly depends on the type of exercise, and partly on how intense it is. Top-level athletes train every day, but usually take a break for a couple of days after an event because the exertion is so intense that they need to let the damage heal. There are lots of people who run 5 miles every day, or bicycle 20-30 miles, or walk on a treadmill for an hour, or do Pilates, etc. Looie496 (talk) 13:09, 30 April 2014 (UTC)

Have you looked through the refs at the article you linked? This paper "Definition, Types, Symptoms, Findings, Underlying Mechanisms, and Frequency of Overtraining and Overtraining Syndrome" seems like a decent overview, but it is not freely accessible. [10]. As usual, you can probably get it via WP:REX. SemanticMantis (talk) 15:13, 30 April 2014 (UTC)

It also depends on your age see: [11]. I know the Daily Mail is not the most reliable source but one of the quotes from a cardiovascular surgeon says "As we get older the efficiency with which the heart pumps blood round the body and the way both the heart and the muscles use oxygen in the blood changes and becomes less efficient". And from my own original research I can tell you that when you get into your sixties a bit of damage to a muscle by overworking it can take months to repair. Also see this and this. Richerman (talk) 08:46, 1 May 2014 (UTC)

How is the Electron configuration in other Dimensions???:

How is the Electron configuration in other Dimensions???:

Dimension 2: (THAT must be RIGHT!!!...)

x² [+0]: s₂ - p₂ - d₂ - f₂ (2_s + 4_sp + 6_spd + 8_spdf...) : [ 2-⁴-6-⁴-10-⁶-16-⁶-22-⁸-30-⁸-38...]

Dimension 2: (THAT must be FALSE!!!...)( "Pauli spin -1/2 +1/2 rule...)

x² [+2]: s₂ - p₄ - d₆ - f₈ (2+6+12+20...) : [ 2-⁶-8-⁶-14-¹²-26-¹²-38-²⁰-58-²⁰-78...]

Dimension 3:

x³ [+4]: s₂ - p₆ - d₁₀ - f₁₄ (2_s+8_sp+18_spd+32_spdf...) : [ 2-⁸-10-⁸-18-¹⁸-36-¹⁸-54-³²-86-³²-118...]

Dimension 4:

x⁴ [+6]: s₂ - p₈ - d₁₄ - f₂₀ (2+10+24+44...) : [ 2-¹⁰-12-¹⁰-22-²⁴-46-²⁴-70-⁴⁴-114-⁴⁴-158...]

[ Noble Gases ]

2-2-2 = Helium

8-10-12 = Oxygen-Neon-Magnesium

SPYROU Kosta - Greece - Honeycomp (talk) 14:02, 30 April 2014 (UTC)

There was a Chemistry Olympiad question some years back that asked this question for 2 dimensions; you might like to dig that up. IBE (talk) 02:36, 1 May 2014 (UTC)

SPYROU Kosta: I didn't knew that...I only thought that IF the Physics make calculations in 10 Dimensions... THEN they have to calculate the electron configuration too...(???!!!)... I also ask if the elektron configuration:{s2-p6-d10-f14} says something about our three Dimensional Space???... - Honeycomp (talk) 14:03, 1 May 2014 (UTC)

I'm no expert, but I think it's more likely to be the other way around - the specific shell sizes are a function of their being embedded in three-dimensional space. 3-space has its basic metric and geometric properties whether or not an atom is present, but the properties of the atom are strictly determined by its embedding in the space. When physicists - usually string theorists - speak of 10 or 26 dimensions, they're not proposing that our space is a 3-dimensional hyperplane through a higher-dimensional Euclidean space. Rather, as our article on string theory explains, they suggest that the additional dimensions are very compact - that the possible extension of anything into them is orders of magnitude smaller than even an electron orbital. AlexTiefling (talk) 14:18, 1 May 2014 (UTC)

SPYROU Kosta: THANKs Alex!!! - Honeycomp (talk) 01:10, 2 May 2014 (UTC)

Extracting neutronium from a neutron star

Say there's a neutron star nearby, and we want to extract some neutronium from it. If we wanted to break off a tiny piece of it, would throwing an asteroid at it do anything, or would it be largely unphased? ScienceApe (talk) 14:23, 30 April 2014 (UTC)

It would do very little, both because of the low relative mass of the asteroid and because of the low density. It would be like shooting a cotton ball at a mountain. However, if you could accelerate a Jupiter-sized planet to near light speed, that might do something. But, of course, if you can do that, you can probably make your own neutronium with a lot less effort. StuRat (talk) 16:15, 30 April 2014 (UTC)

If you could, it probably wouldn't stay neutronium long enough for you to use it for any purpose. Once it is taken from the star, and is no longer subject to the extreme pressures that made it neutronium, it would either become free neutrons, or degrade back to protons and electrons. --Jayron32 16:21, 30 April 2014 (UTC)

Big, common misconception: Neutron stars aren't all neutronium. They have a pretty thick crust of other stuff on top of it. I would, however, like to see more about what happens to neutronium as pressure is reduced... I have a feeling there must be some neat surprises. Wnt (talk) 19:45, 30 April 2014 (UTC)

A degenerate neutron gas would be a pretty nasty thing to come across at STP conditions. Radioactive, extremely toxic, highly carcinogenic. Plasmic Physics (talk) 06:08, 1 May 2014 (UTC)

<tl;dr>Think about it that way:

On a high-gravity planet, a spring is compressed by its own weight. Now have Scotty of Star Trek beam it up, into the 1g environment of the USS Enterprise. It will expand immediately and, depenging on the surface g of the planet, jump around more or less violently, possibly killing one of the redshirts in the process. (Big surprise.)

Now, neutron-degenerate matter is extremely elastic. (Contrast electron-degenerate matter, which is "only" completely awesome.)

Worse, one cm³ of neutron-degenerate matter is heavier (or more massive to be precise) than a battleship. If you extract it, it'll not only expand to about that size, but it will do so extremely fast. (A neutron star has an extremely high surface gravity; if you dropped something from a height of 1 cm, it would hit the surface at roughly 150km / 100 miles per second.

So, how fast would your sample expand? After 1cm of expansion (from a radius of ~0.6cm to ~1.6cm), its surface would move at that velocity (think of the spring; it could sustain that kind of pressure on the surface, so it'll exert that pressure when external forces vanish). This is only an order-of-magnitude result, but poor Scotty wouldn't have time to pull one of these if it happened.

Would it continue to expand?

It wouldn't accelerate much beyond that point, but the matter would impact the walls at about 100km/s. And we're looking at a lot of matter, easily outweighing the entire Enterprise.

</tl;dr>Like Jayron32 said, it won't stay degenerate. - ¡Ouch! (^{hurt me} / _{more pain}) 06:57, 6 May 2014 (UTC)

Protein and ingestion

Does this link say that only 20 g of protein is utilized by the body and that too it should be taken for every 4-5 hours and anything other than that will be a waste of protein ? http://www.exercisebiology.com/index.php/site/articles/should_you_eat_protein_every_2-3_hours_for_muscle_growth/ — Preceding unsigned comment added by 119.235.54.187 (talk) 17:28, 30 April 2014 (UTC)

Yes, it seems to say 20 grams of protein at a time is as much as your body can use, however, they only tested with it taken every 2-3 hours, but theorized that an interval twice that long might work, too, as amino acids (the building blocks of protein) remain in the blood after that. Also, taking 20 grams every 2 hours, while awake, would get you to an absurd amount of protein, like 400 grams. That's almost ten times what a normal person needs, and may be too much for your kidneys to process. Myself, I can tell when I've eaten more protein than my body can use, because my urine smells like bacon (which I believe to be amino acids). I don't agree when they say that eating protein every 2-3 hours is inconvenient. Just keep a bag of nuts with you (assuming you're not allergic) and nibble on them all day long. (Make sure they are unsalted, though, or you will get a sodium overdose.) If you find them unpalatable, add in some raisins. StuRat (talk) 19:49, 30 April 2014 (UTC)

@StuRat So if we assume it works for 4-5 hours then it means even 5*20 i.e 120 gms of protein is optimal for our body ?? — Preceding unsigned comment added by 119.235.54.187 (talk) 05:20, 1 May 2014 (UTC)

5x20 = 100, but that's still about twice the amount of protein we normally need. However, a bodybuilder or athlete might need that much. StuRat (talk) 14:05, 1 May 2014 (UTC)

Blended color perception

Based on our discussion earlier on this Desk, it came up that humans are unable to distinguish between an object which reflects the green frequency of light and one which reflects both the blue and yellow frequencies of light. This isn't the case for sound, where we can distinguish a medium frequency from a high and low frequency heard simultaneously. So, do any other animals seem to have the ability to distinguish blended colors ? Do any people have this ability ? If so, how do they describe the difference ? StuRat (talk) 22:02, 30 April 2014 (UTC)

Light perception is the stimulation of certain rods and cones in your retina right? So green light must stimulate the same receptors as yellow and blue light... This is incorrect by the way, yellow and blue PIGMENTS make green, yellow and blue LIGHT make white. Regardless, I get what you mean. We have Trichromatic vision, this is what lets us distinguish the different colors, different light stimulates our three different receptors, which are obviously deficient because 2 different sources of light can stimulate exactly the same proportion of receptors in our eyes. As might have been mentioned before, there is nothing qualitatively different between the colors, they are different frequencies of a continuously varying spectrum. The mantis shrimp has not three, but SIXTEEN photoreceptor pigments, it would no doubt distinguish between green and "yellow and blue", how would it describe it? I guess the same as you would describe the difference between two different colors. Vespine (talk) 22:59, 30 April 2014 (UTC)

Also, in respect to other people, at least one person HAS been confirmed as Tetrachromatic, and possibly it's not extremely rare. However it sounds like this makes a measurable but not extreme difference to their color perception, I don't believe it's like they can perceive a whole new color we don't "know", i think it just means they are able to more easily distinguish between more shades of colors than most people. Vespine (talk) 23:06, 30 April 2014 (UTC)

Actually, functional tetrachromacy has never been validated in a human, though genetically speaking, it is speculated that a tetrachromatic combination of photoreceptors could manifest in a woman, due to variations in a specific allele. However, this would be exceedingly rare and even if that particular combination did exists in the retina itself, there's a high degree of uncertainty that the neurological pathways for color perception within the brain itself would be able to process the additional colors in a way leading to an actual or significant expansion of differentiation between colors. I say uncertain and not impossible because some six or seven years back, a research team genetically modified some mice (naturally dichromats) to be trichromats. They did this with the assumption that they would be confirming that the mice would still be functional dichromats, despite the trichromatic retinas, but to their amazement (and with repercussions to this field of study that are still being weighed today), they discovered they had created true trichromats (these mice, and others in replicated studies) seem to be able to distinguish between colors with near the same level of differentiation found in normal trichromats; the mammalian visual cognition centers are apparently more plastic in this regard than anyone ever suspected. Now, obviously, the fact that this worked with regard to mice moving from the level of dichromat to trichromat does not necessarily mean the principle would hold with humans, or any trichromat, who possesed tetrachromatic retinas, but it is a fascinating area of inquiry. For the record though, the upgrade would not be minor if the neural architecture matched the capabilities of the eye; human vision could go from being able to distinguish roughly one million hues to possibly over 100 million, though this would depend on the specific wavelength of light which the new photoreceptors were sensitive to -- for example, it's worth noting that the theoretical tetracrhomat women who are postulated would actually have a fourth type of photoreceptor that is really not all that far off in the wavelengths detected from that of one of the existing cell types, so the upgrade would be minimal for them, even if the visual centers of their brain were up to the task of processing the information. Snow (talk) 00:04, 1 May 2014 (UTC)

@Snow Rise: you said they tried to change dichromat mice into trichromats, but actually got tetrachromats. Is that what you meant to say ? StuRat (talk) 01:38, 1 May 2014 (UTC)

Wooops, no, it was not. Thanks for the catch, Stu. I've edited the passage above to read as it should have -- that is, that they created trichromats. Sheesh. Snow (talk) 01:49, 1 May 2014 (UTC)

@Snow Rise: Nice try, but you ended up with "tritrachromats". Is that hybrid, or are you editing under the influence ? :-) StuRat (talk) 03:24, 1 May 2014 (UTC)

LOL, yes - of sleep deprivation. Thanks again! Snow (talk) 04:17, 1 May 2014 (UTC)

Also, you claimed functional tetrachromacy has never been validated in a human, but even in the article that I linked it states: In June 2012, after 20 years of study of women with four cones (non-functional tetrachromats), neuroscientist Dr. Gabriele Jordan identified a woman (subject cDa29) who was able to detect a greater variety of colors than trichromatic ones, corresponding with a functional tetrachromat (or true tetrachromat). I had actually heard of this case before looking up the article. Vespine (talk) 04:31, 1 May 2014 (UTC)

Well, I recall that story but to the best of my knowledge the details of that case and the testing procedures were never released to peer-review and were only reported in the general press and I remember my general impression of the details that were released was that they raised more questions as to the verification procedure than they answered. The fact that this case has still not seen review in research literature since then raises further questions as to how verifiable the findings were. That said, Dr. Jordan is known for research in this field. It's possible she did in fact find a functional tetrachromat, but I'd take the claim with a grain of salt until the testing procedure is better validated. I also tend to doubt that, even she did have some increased differentiation, that the subject in this case was seeing a vast new spectrum of colors, as per the question of the ability of the visual modules of the human brain to keep up. Snow (talk) 05:45, 1 May 2014 (UTC)

As a complete aside, why does everyone only ever talk about green as being a mix of yellow and blue, when some greens are obviously a mix of yellow and indigo? RomanSpa (talk) 09:10, 1 May 2014 (UTC)

Problem #1 is that people talk about mixing paint/dyes (which is subtractive mixing) versus mixing light (which is additive mixing). In light, green is a primary color (for trichromat humans) - so you can't get it by mixing anything else. In subtractive mixing, it's usually said to be a mixture of yellow and blue.

Problem #2 is that "blue" is a pretty vague term for most people. The more sciency thing would be to say that in subtractive mixing, green is a mix of yellow and "cyan" (cyan being a pale "sky-blue"). Yellow paint absorbs blue light and reflects red and green. Cyan paint absorbs red light and reflects blue and green. A combination of the two absorbs red and blue and reflects only green. Hence yellow plus cyan makes green.

Pure blue paint would absorb red AND green and reflect only blue light - mixing that with yellow would result in all three primaries being both reflected and absorbed - so the resulting color is likely to be muddy and the exact color you perceive would be sensitively dependent on the dyes and the ratios of the colors and so forth. "Indigo" is another vague color description...it's hard to say what exactly it is...best description is a very dark blue..which would mean that it absorbs some blue light as well as all of the red and green.

Problem #3 is that paint can be laid onto a bright white surface or a dark one - and the consequences for light transmission get really complex. Some light is reflected from the surface of the paint - some passes through the paint, reflects off of the backing material and is then selectively absorbed on the way back out. Since some chemicals in the dye reflect color differently than they transmit it - you can get all sorts of complicated effects by mixing them.

Problem #4 is that when you're mixing light, you have a self-contained system that's easy to describe. With paint and dyes, the color of the incoming light matters. Sunlight is yellowish - and the sky is blue - so you get color changes depending on whether the material is in sunlight or shaded (and therefore lit mostly by blue light from the sky). Interreflections between objects add more complexity - and the fact that our eyes and brain adapt to the prevailing light color and attempt to produce 'perceptual' colors that match what the underlying object's color "should be" if it were not for colored light falling onto it. This mess can get very confused - such as when you view the world lit by old-fashioned orange sodium streetlamps.

SteveBaker (talk) 16:16, 1 May 2014 (UTC)

You can get green light by additive mixing of yellow and cyan light, as you can see from a chromaticity diagram. -- BenRG (talk) 03:44, 3 May 2014 (UTC)

Ah, that might be what's going on: you think indigo is just the same as blue. My father can't tell when something is indigo or not either - you show him something indigo and he just says it's blue. I suppose if other people have this problem (blue/indigo colour-blindness?) it might explain the confusion. (It would also explain why so many people wear clothes that clash horribly with indigo jeans, but that's another story!) If you can't see the difference between blue and indigo I suppose you wouldn't be able to see the difference between yellow-blue and yellow-indigo either. RomanSpa (talk) 05:50, 2 May 2014 (UTC)

Curious. To me, indigo never seemed like a "real" primary color, just something shoehorned into a list of colors of the rainbow. It's not that I can't tell it from blue, but it seems closer to both blue and to violet than cyan seems to blue or to green. I'd think an "indigo-yellow" would just be a slightly blue green, though not as blue as cyan. I wonder if the difference is all semantics or if there's actually a variation in photoreceptor profiles. Wnt (talk) 12:16, 2 May 2014 (UTC)

Without somehow wiring up your eyes to my brain, and vice versa, we probably can't ever know. It's intriguing that you see indigo as closer to blue and violet, though - to me, the difference between blue and indigo (or indigo and violet) is as large as that between yellow and green. It's probably just individual variation. RomanSpa (talk) 18:53, 2 May 2014 (UTC)

Are you sure you're both talking about the same blue and indigo? Are they   and   as shown in Indigo#Classification as a spectral color, or   and   as shown in the respective articles' infoboxes?

Indigo was in fact shoehorned into the list of spectral colors by Isaac Newton for a silly reason, as the article mentions. -- BenRG (talk) 03:44, 3 May 2014 (UTC)

Yea, they list these colors:

Red:  Orange:  Yellow:  Green:  Blue:  Indigo:  Violet: 

But I would classify them differently:

Red:  Orange:  Yellow:  Green:  Cyan:  Blue:  Violet: 

StuRat (talk) 16:28, 3 May 2014 (UTC)

Ah, I see. This was Newton's classification, and is a function of both antiquity and perhaps the variation of medieval English also. But does @RomanSpa: use a definition like that, or the modern one? Wnt (talk) 23:07, 3 May 2014 (UTC)

Gosh, this is still going on! I wouldn't classify either Indigo:  or Blue:  as "indigo", though this may be partly because screens always get things wrong with the blues and indigos and violets anyway. This is closer to indigo:   - it's what the article on indigo calls "electric indigo". According to the article it's in the middle of the "indigo" range, though it doesn't seem like an "average indigo" to me. Annoyingly, the more I think about this the more confused I get, because naming colours is so subjective - think how many shades of green get just vaguely classified together as "green" (I vaguely remember that it's even worse in Japanese, where they count some blues as green too!). RomanSpa (talk) 05:25, 4 May 2014 (UTC)

Now that I see it next to the "violets" above I'm even more of the view that it's not quite right either. The problem is partly that the violets aren't "violet" enough, though this may be an illusion because of the screen. RomanSpa (talk) 05:29, 4 May 2014 (UTC)

Well, all our experience is subjective, though I suppose there's a social science of how people calibrate and recalibrate color. For example, my own experience of indigo was formed from ancient Crayola crayons (though according to the indigo article they've since redefined the color to something none of us would call indigo), included in popular kits presumably for the nearly sole purpose of drawing "proper" rainbows with blue, indigo, and purple, though such look like anything but a proper rainbow. The shade I recollect was somewhere between "midnight blue" and "persian indigo", though I think my modern choice would be to pick pretty much persian indigo directly. Blue, purple, and cyan, however, have all been pretty thoroughly redefined in my mind by RGB monitors. Also, in my mind violet is a "real" color obtained from a prism (and virtually no other source) while purple is a "false" color. I'm not absolutely sure I'd even tell them apart yet I still have the sense that there's something about violet that a monitor cannot duplicate, and that purple is "unstable". But I don't see how to move from all our little anecdotes and stories to anything scientifically informative, or indeed, replicatable by anyone else. And if we really want to get into the craziness of subjectivity... then there's my crank opinion that, because all sensation has pitch and the pitch of something seen is its color, that the beauty of something has a color that is completely distinct from that of the object/person itself. Wnt (talk) 05:15, 5 May 2014 (UTC)

That sort of matches my feeling: violet seems to me very different from purple, but people use the words interchangeably. RomanSpa (talk) 15:05, 5 May 2014 (UTC)

SPYROU Kosta: "they raised more questions as to the verification procedure than they answered" This is the problem by most things!!!... THANK you both for this interesting article!!!... It helped me a lot!!!... - Honeycomp (talk) 23:23, 4 May 2014 (UTC)

May 1

If I can smell something is it losing mass?

If I can smell something I suppose it means that thing is being dissolved into the air. Is it therefore losing mass? Hayttom 11:10, 1 May 2014 (UTC) — Preceding unsigned comment added by Hayttom (talk • contribs)

Yes. --Jayron32 12:13, 1 May 2014 (UTC)

Odor implies such. It says "low concentrations", i.e. you're only inhaling a very small quantity of whatever is being emanated, but obviously if you're sensing it then it's no longer "attached to" its source, hence its source is losing some small quantity of mass. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:26, 1 May 2014 (UTC)

I suppose an exception is if the item modifies existing air in some way, so as to make it have an odor. Air purifiers which create ozone and space heaters which burn dust in the air might qualify. StuRat (talk) 13:55, 1 May 2014 (UTC)

Also, when you can no longer smell it, that implies that the volatile compounds have all evaporated/sublimated into the air. Of course, grinding off the surface may expose more volatiles. StuRat (talk) 13:59, 1 May 2014 (UTC)

Supposing you had an open container of a common substance such as rubbing alcohol. Once it "totally" evaporates, isn't there still some residual scent in the container? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:12, 1 May 2014 (UTC)

In that case, it's highly likely that there are some impurities in the alcohol that are still producing smell - and that some of the alcohol has been absorbed into the container somehow. But if it's literally all gone - then of course there can be no smell.

Smell is only possible if some of the molecules of the substance made it into your nose somehow...if there are literally no molecules left - then there obviously isn't going to be any smell. But even humans - with our relatively poor sense of smell - can detect quite low concentrations of some substances...so there may not have to be very much left for us to detect it.

To answer the question though - it may be that the substance is emitting some chemical but absorbing something else. So you could imagine something absorbing water from the air while emitting something else. In that case, the bulk of the material could increase while the smell is being emitted. If there was some kind of chemical reaction with something in the air that produced the smell - then it's quite possible that the result is an increased mass. Imagine something which reacts with air to make nitrous oxide. That stuff smells slightly sweet - but we might imagine some solid that absorbs oxygen and produces nitrous oxide as a byproduct...it would gain mass as time goes on and continue to generate that slightly sweet smell until the reaction is complete and the mass has increased.

SteveBaker (talk) 15:36, 1 May 2014 (UTC)

Good point. For example, what about the bloated blue whales discussed in this (fairly gross) story?[12] Could they be gaining mass as they decompose? Or is the decomposition merely re-arranging molecules already existing within the carcass? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:43, 1 May 2014 (UTC)

I guess mass might be passing from the air to the solid (or semi-solid) parts of the carcass. But the fact that the body is capable of inflating like that suggests that any gases involved in that reaction were wholly contained by the carcass all along. I can't say the same for any decomposition at the outer edge - some substances might be oxidising, in which case they'd be gaining mass from the wider atmosphere, but they might also give off odour and other things at the same time, resulting in mass loss. AlexTiefling (talk) 15:48, 1 May 2014 (UTC)

I very much doubt that the bloated whales are gaining mass. They are getting bigger - but that's just gasses as a decomposition byproduct. I don't think they are getting any heavier. SteveBaker (talk) 16:36, 1 May 2014 (UTC)

Thanks, everybody. Hayttom 08:31, 6 May 2014 (UTC)

Resolved

Mr Frosty (is such fun; he makes treats for everyone)

Did Nalgene have to make a deal with the toy manufacturer to call their cryogenic storage containers "Mr Frosty"? --129.215.47.59 (talk) 12:48, 1 May 2014 (UTC)

There's no reference to a "Mr Frosty" in the Nalgene article. Do you have more details you could share with us? ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:58, 1 May 2014 (UTC)

Try [this search string]. --129.215.47.59 (talk) 16:36, 1 May 2014 (UTC)

With trade names like that, there are generally only legal problems if the public are likely to confuse the two products. It's a legal minefield though - and these things often end up in court even when the layman would say there was clearly no confusion. For example, I recall a legal battle in the UK between Digital Equipment Corp (DEC) and the company that begat the Dyson vacuum cleaner. DEC had a computer called "VAX" and there was a vacuum cleaner called "Vax". You'd think it was obvious that there was no conflict - but it didn't stop them from winding up in court. In that case, it was ruled that nobody had infinged on anyone's trade name because there was no possibility of confusing a gigantic minicomputer with a domestic vacuum cleaner - so nobody had to rename anything and no money had to change hands. However, such battles do often end up in bloodbaths - the Apple record company (which was owned by the Beatles) wound up in court with Apple computers (the fact that their logos were almost identical didn't help!). But it was ruled to be OK so long as Apple Computers didn't make or sell music...which they didn't back in the era of the Apple 2 computer. Well, you can imagine what went wrong when Apple produced the iPod and started selling music on iTunes...which clearly COULD result in confusion between the record label and the music sales service. The resulting bloody re-run of that legal mess explains why, for the longest time, you couldn't buy Beatles music on iTunes.

SteveBaker (talk) 15:24, 1 May 2014 (UTC)

• According to Trademark247, "Mr. Frosty" is a registered trademark of Nalge Nunc International Corporation. According to this page, it is also a trademark for Sea Watch International Corporation, for use in labeling seafood. I can't find any information on the use of the name as a trademark for toys. Looie496 (talk) 01:00, 2 May 2014 (UTC)

Using napalm in a car instead of gasoline

What would happen if you used napalm in a car's gasoline tank instead of gasoline? Would it blow up or would the engine just fail to start? ScienceApe (talk) 13:42, 1 May 2014 (UTC)

Napalm is gasoline - with the addition of substances to make it into a thick gel. The modern form of it is only about 33% gasoline, the rest is polystyrene and benzene. So even if you could somehow get it into the cylinder, there isn't enough gasoline in there to run your engine. Another problem (aside from whether your fuel pump could pump it) is that the fuel injectors in a car engine are designed to spray the fuel as very fine droplets. I doubt that it could do that with something as gelatinous as napalm.

I strongly disagree with the assertion that gasoline is "highly explosive" - as a liquid, it's really quite hard to even set on fire. Only the vapor from it will burn at all. So you need it sprayed in fine droplets with a large surface area to evaporate from to get it to burn quickly enough. If you toss a lighted match into a bucket of gasoline, the match goes out...there is no exciting "Kaboom!". I'd also argue strongly against the assertion that a car engine is a controlled explosion. Fuel burns in the cylinders - it doesn't explode.

The significant difference is that most explosives contain their own oxygen. For example - when nitroglycerin explodes:

4 C₃H₅N₃O₉ ==> 12 CO₂ + 10 H₂O + 6 N₂+O₂

Everything that's needed to make it go "boom!" is right there inside the nitroglycerin molecule...so it's easily able to explode.

Gasoline, on the other hand, requires LOTS of oxygen to make it burn. Gasoline is a complicated mix of chemicals - but one of the main ones is octane. Here is how octane burns:

2 C₈H₁₈ + 25 O₂ ==> 16 CO₂ + 18 H₂O

As you can see, you need 25 oxygen molecules for every two molecules of octane. Octane itself contains no oxygen whatever - so it can't even burn by itself, so it certainly won't explode. You've got to mix it with LOTS of oxygen to get it to combust - every molecule of the octane needs to be close enough to 25 oxygen molecules to react - and that's why it has to be in vapor form. Once that happens, the reaction goes quite quickly - and lots of byproduct means that the volume increases rapidly. You can call that an "explosion" - but it's no different than how wheat flour or sawdust will burn so rapidly that the effect is explosive if you get it in a fine dust up in the air. However, a grain of wheat or a lump of wood isn't "an explosive" - and neither is gasoline.

That's why people who want their cars to go faster get fixated on turbo-chargers and super-chargers and big air scoops - getting more air into the engine is needed to get more gasoline to burn in order to make the car go faster. If you had a car that ran on nitroglycerin, you wouldn't need an air intake at all.

SteveBaker (talk) 15:10, 1 May 2014 (UTC)

If you google "automobile engine controlled explosion" you will find plenty of references, so if you don't like that characterization of the process, go complain to those individual writers, not to me who merely quoted them. Also, what's the answer to the OP's question, "...would the engine just fail to start?" I'm guessing it would indeed fail to start, but you're the expert, so we'll defer to you an that one. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:35, 1 May 2014 (UTC)

If you google "magnets cure rheumatism" or "obama not US citizen", you'll get lots of hits too...doesn't make it true. SteveBaker (talk) 16:34, 1 May 2014 (UTC)

One of the links that turns up is this, from the "How Stuff Works" department of the Discovery Channel. Feel free to contact that fringe group and tell them why you're right and they're wrong. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:07, 1 May 2014 (UTC)

To be somewhat fair to Bugs, sometimes "combustive expansion of gases" is sometimes referred to as a low explosive while those that truly detonate are sometimes referred to as a high explosive. Low explosives occur when any combustible material is confined in a tight space; i.e. what happens in a piston chamber of a car engine. It just depends on what terminology you use. Some people prefer to not use the term "low explosive" because it confuses the very chemically different processes of "deflagration" and detonation. --Jayron32 16:52, 1 May 2014 (UTC)

As far as I'm aware, a detonation is just an explosion that propagates through the explosive medium at supersonic speeds. That tends to create a much sharper and more damaging shock wave. I don't often disagree with Steve, but I think it's not unreasonable to describe what happens in a combustion engine as a controlled series of fuel-air explosions. --Stephan Schulz (talk) 09:40, 2 May 2014 (UTC)

To add (not sure if it's helpful), there is a technical difference between a rapid burning and a detonation. This was vividly shown in a safety video for silane which will usually readily burn in air (violently). And sometimes it will mix and detonate. I don't know if engines burn or detonate gasoline but the video was cool for silane. --DHeyward (talk) 02:41, 4 May 2014 (UTC)

In direct answer to your direct question – it is a hydro-carbon, so a compression ignition engine (one that runs on diesel fuel) would run just like it was fueled by any other hydrocarbonous fuel. Don't have any reference to hand but I think you'll find that the naphthoic acid component of napalm is a corrosive by-product of the petroleum industry. It is a very cheap by-product. In modern fuel injected engines, this I think, would cause less problems. However, I it think it corrodes steel pipe lines as well. The combination of naphthoic acid and palmitic acid might also jell, causing the fuel delivery system to gum up. It is slow to vaporize, so a carbureted engine is unlikely to run without with out carb-heat.--Aspro (talk) 19:48, 1 May 2014 (UTC)

vitreous humor

Where does vitreous humor come from? If it's already present at birth, what organ (or other source) secretes it during gestation? Babies' eyeballs are smaller than adults, so as a person grows, where does the extra humor come from? 2001:18E8:2:28CA:F000:0:0:2B89 (talk) 14:00, 1 May 2014 (UTC)

Never mind, the page explains it, and I didn't see it until re-reading. "It is produced by cells in the non-pigmented portion of the ciliary body deriven from embryonic mesenchyme cells which then degenerate after birth." But could you help me understand what this means? I saw ciliary body, but I don't understand what a mesenchyme cell is. 2001:18E8:2:28CA:F000:0:0:2B89 (talk) 14:03, 1 May 2014 (UTC)

In 1879, Charles Sedgwick Minot, an anatomist based out of Harvard Medical School in Boston, Massachusetts, first described what he termed mesamoeboids, the cellular portion of what would soon come to be recognized as mesenchyme. Minot found these cells in the context of histological studies of mesoderm. He understood the loose, mobile cells of mesenchyme as primitive representatives of the mesoderm, but did not consider these cells as a type of tissue. Two years after Minot’s recognition of mesamoeboids, Oscar and Richard Hertwig, two brothers and doctoral students of Ernst Haeckel at the University of Jena in Jena, Germany, coined the term mesenchyma in their publication Die Coelomtheorie. Versucheiner Erklärung des mittleren Keimblattes (Coelom Theory: An attempt to explain the middle germ layer), and they used it to describe the type of tissue that was comprised of the amoeboid cells that Minot had portrayed. The Hertwig brothers established that mesenchyme originates from mesoderm, and they situated this relationship in the broader context of the development of the coelom, a fluid-filled body cavity. Their Die Coelomtheorie also advanced the idea that the three germ layers maintain separate identities and develop distinct tissues and organs, a concept known as germ-layer theory. (Source: http://embryo.asu.edu/pages/mesenchyme) Basically, mesenchymal cells are the precursors of cells of the mesoderm, which will later become your blood and muscles. 140.254.227.117 (talk) 14:28, 1 May 2014 (UTC)

Hmmm, come to think of it... it is not commonly, but nonetheless repeatedly has been observed that a choristoma of the lacrimal gland can occur in the ciliary body and/or connected iris tissue. Now embryologically, the brain (from which the eyes branch out) is a folded in layer of the outer epidermis. Assuming this indicates some real affinity between the cell types, does that make the ciliary body with its aqueous and vitreous humor production a sort of a sweat gland, and vitreous humor a sort of "mucus"? (To be clear this is outrageous speculation, and I'm not sure how I'd go about trying to prove such thing) Wnt (talk) 16:16, 2 May 2014 (UTC)

Andromeda...

The nearest Galaxy to the Earth is Andromeda...

You nead 2,5 Years if you travel in Space with 1.000.000 * c !!!!!!...

_{(c = 300.000 km/sec)Light speed}

I cannot imagine that!!!...

You???...

SPYROU Kosta - Greece - Honeycomp (talk) 14:32, 1 May 2014 (UTC)

I have more difficulty imagining a plausible faster-than-light propulsion method than I do contemplating how far away the Andromeda galaxy is. For what it's worth, there are several nearer galaxies (apart from the Milky Way) such as the Large Magellanic Cloud However, this 'question' appears to be a request for opinions rather than anything a reference desk can help with - it's best not to ask that sort of question here, as the header explains. AlexTiefling (talk) 14:40, 1 May 2014 (UTC)

There is, if I got this right, another galaxy which is even closer than the Magellanic clouds. They are hard to detect because they are on the "wrong" side of the Milky way. - ¡Ouch! (^{hurt me} / _{more pain}) 08:28, 6 May 2014 (UTC)

If you mean the cognitive processes that run in the brain when you use the term "imagination", I suppose you - assuming that you are human and have your prefrontal cortex and other areas in tact and normally functioning - can in fact imagine it like any other concept. This may be of interest to you. Source: http://scienceblogs.com/developingintelligence/2007/05/31/the-neuroscience-of-imaginatio-1/ 140.254.227.117 (talk) 14:47, 1 May 2014 (UTC)

SPYROU Kosta: I wanted to point only that IF we could travel faster than Light... faster * 1.000.000 is enormous!!!... Honeycomp (talk) 14:50, 1 May 2014 (UTC)

SPYROU Kosta: THANK you 140.254.227.117 about your consern for my Brain Health!!!... You are so "kind" and "childish"... :-) Honeycomp (talk) 15:04, 1 May 2014 (UTC)

I think we're coming to the point where this joke isn't funny any more. RomanSpa (talk) 05:53, 2 May 2014 (UTC)

...and please (I've seen that one a lot, not just on the ref desk or on the internet) do not call the galaxy "Andromeda." Andromeda is a constellation; the galaxy is called the Andromeda nebula or the Andromeda galaxy. - ¡Ouch! (^{hurt me} / _{more pain}) 08:28, 6 May 2014 (UTC)

Comets and Aristotle

If Aristotle thought the heavens were unchanging and perfect, how did he account for comets? Looking around on Google produced the sublunary sphere article but nothing else, really. The article notes that Tycho's observation of a nova undermined the Aristotelian position, but it also says that comets likewise undermined it, and I don't understand why, since comets have been well known and rather common throughout human history. 2001:18E8:2:28CA:F000:0:0:2B89 (talk) 14:49, 1 May 2014 (UTC)

He figured gases rose from Earth to high in the atmosphere, where they ignited and burned either quickly (meteor) or slowly (comet). Meteorology (Aristotle) has a link to the English text to the book; Book I deals with these "fiery exhalations". 88.112.50.121 (talk) 16:14, 1 May 2014 (UTC)

Impedance matching between transmission lines

I have a project that requires good broadband (upto 1GHz say) matching between a 50 ohm parallel plate line and a 350 ohm parallel plate line. Im wondering what would be the better method: a) straight tapered matching section or b) exponential tapered section. Also, what length of section should I use for each of the above methods to get a better than -20dB match upto 1GHz? --109.151.101.168 (talk) 14:53, 1 May 2014 (UTC)

One issue is that different wavelengths will require different transition lengths. So at 1 MHz it would be 1000 times longer than at 1 GHz. Have you got a lower limit on frequency or do you need to go to DC? Are your two parallel plates sections the same separation and only differ in width? Exponentiation transition will be better. I ran an optimization for you with 4 fixed sections, which gives 73.8 108.9 160.7 and 237.1 Ohms, (values should be at fifth root of 350/50 powers) but this still only gives you 82% power transfer, no-where near the 99% you want.[13] Graeme Bartlett (talk) 23:01, 1 May 2014 (UTC)

As suggested here, it is the lower end of the matching band that will be the difficult end. Without that specification the problem is ill-defined (or impossible, if you require down to DC). Wouldn't it be great if we could build DC transformers that are 99% efficient out of a simple shaped transmission line? —Quondum 00:07, 2 May 2014 (UTC)

The problem is most certainly incompletely specified. Power level? Does it need to be bidirectional or are you interested in power flow in only one direction? If you don't need bidirectionality, the simplest, most boardband approach is to use a transistor - if matching from low Z to High Z use a common base circuit. That can go down to DC if necessary. If bidirectionality over a very board band is required, you can use a gyrator. What is important - low return loss and flat response (eg an intrumention problem) or efficient power transfer (eg a transmitter or radio reciever front end)? Most truely boardband applications are instrumentation/measurement applications, so power loss doesn't matter so much, but low reflection is critical. In such cases, use a resistive matching pad - which inherently goes down to DC as well as as high as you need when carefully constructed with chip resistors. Matching with intermediate matching steps and stubs is inherently narrowband as has already been said. 1.122.161.156 (talk) 10:49, 2 May 2014 (UTC)

In reply to Graeme's posting and helpful calculation of reflection coefficient etc, no, I dont need a dc response as I am sending fast pulses from a low impedance charge line into the high impedance line by means of avalanche switches. To give an indication of the low end response: I can stand, say, about 10% droop on the top of my pulses. What this means as a lower frequency limit of the matching section, I am uncertain.

In reply to 161.156: Power is pulsed but average is only likely to be milliwatts. I do need biderectionallity as the switches are in the low impedance line. Transistors in normal operation modes are unlikely to work at the sub nanosecond rise times I need. My basic need is to get maximum power transfer from the low Z line to the hiZ line.

Any more thoughts greatly appreciated.109.151.101.168 (talk) 13:22, 2 May 2014 (UTC)

PS: parallel plates are same width but different spacings.109.151.101.168 (talk) 13:24, 2 May 2014 (UTC)

You stated an upper frequency limit of 1 GHz, which will approximately reproduce a step taking no less than 0.5 nS. Transistors are readily available that will give that sort of bandwidth. In any case, at the power level you specified, quite ordinary silicon NPN RF transistors can be used in avalanche mode to provide sub-nanosecond pulse rise times. This technique has been common in sampling oscilloscopes since the 1960's when transistors could barely work to 200 MHz in linear mode. To find the low frequency cutoff required, you need the pulse repetition frequency, unless some sort of DC restoration phenomenum is operational, in which case you need to know the pulse width and calculate on that. Why does the switch need to be in the low impedance line if you actually want the pulses in the high impedance line? It will be a lot simpler to switch in the hi-Z line. 1.122.161.156 (talk) 14:39, 2 May 2014 (UTC)

The "frequence response" near DC is puzzling. If I apply a very slowly changing voltage to the two conductors why would the output not mirror the input faithfully? Even if I had a length of lamp cord spliced to coax spliced to twinlead? (It's been a long time since the "fields and waves class.) Edison (talk) 13:43, 2 May 2014 (UTC)

Well, yes, but the OP specified a return loss (reflection) better than 20 dB. And we must presume that the response over the frequency range needs to be flat. Using intermediate impedance sections or matching stubs will result in reflected impedance changing with frequency and thus the return loss and power level must change with frequency. Putting it another way, yes, at low frequencies, the voltage on the high impedance line must faithfully copy the input, but it is the wrong voltage, as required voltage for a given power rises with impedance. 1.122.161.156 (talk) 14:39, 2 May 2014 (UTC)

A Time-domain reflectometer would give Edison educational insight into their series connected lamp cord/coax/twinlead. By "mirror faithfully" they presumably expect their input change to produce an output at the speed of light. They will be disapointed because 1) with dielectric insulations between the conductors of the lamp cord, etc. the propagation speed is slower than c, and 2) at each point where they splice leads there is an impedance mismatch that reflects part of any signal (i.e. transient voltage change) back towards the source. It will take considerably longer than the time for one traversal of the cables for transient forward and reflected pulses to die down. Eventually the conductors settle at the same DC voltage throughout but now there is no AC power transmission and Transmission line effect is irrelevant at DC. 84.209.89.214 (talk) 17:30, 2 May 2014 (UTC)

In general, the matching will be good over some frequency if the geometry of the line changes slowly relative to the associated wavelength. This is an optimization problem, so you need to specify what must be optimized. In particular, is it the length of the match? you have already given the acceptable return loss, though that probably is not rigid. My guess is that a smooth exponential taper will be a good start if length of the matching section is to be minimized, but I have no direct experience and will have to defer to others with hands-on experience. —Quondum 15:46, 2 May 2014 (UTC)

The OP requires a passive matching line length L with tapered impedance z(t) ohms where:

z(0) = 50

z(T_L) = 350

t = distance/(speed of light) if the plates are airpaced

A 1V impulse on the 50 ohm input causes a reflected voltage waveform

ø(t) = (z( T_L - t) - 50 ) / (z( T_L - t) + 50 )

Reflected power is maximum at frequency = 2 / T_L so if this must be below -20 dB

integral from t=0 to T_L of ø(t) cos (π /T_L - T_L/2) dt < 0.1

Adjusting the length L and having a non-linear impedance taper could allow the VSWR (a measure of Impedance matching) to be minimised for a limited range of frequencies.

I recommend this venerable application note about applications of Step recovery diodes in pulse generators.

• "Pulse and Waveform Generation with Step Recovery Diodes" (PDF), Application note AN 918, Palo Alto: Hewlett-Packard, October 1984 {{citation}}: Missing or empty |title= (help). Available at Hewlett-Packard HPRFhelp.

84.209.89.214 (talk) 17:51, 2 May 2014 (UTC)

Male and female bell peppers?

According to a perhaps unreliable source, some bell pepper fruits (aka sweet peppers) are male and some are female. Moreover, the "sex" of each pepper can be determined by counting the lobes: 4 lobes = female, 3 lobes = male.

Further, female peppers = sweeter and better for eating raw, male peppers = firmer and better for cooking.

Is there any truth to this? Either the part about two sexes of pepper fruits or the part about the shape of peppers being related to their sweetness and consistency.

I suspect it is pure nonsense but... how does one know for sure? Thanks, CBHA (talk) 19:33, 1 May 2014 (UTC)

I am not a botanist, but I found a knowledgeable-looking blog post that debunks the idea. Capsicum annuum should be relevant, but it doesn't have much information on the morphology of the plant. AndrewWTaylor (talk) 20:09, 1 May 2014 (UTC)

This claim is total nonsense. A bell pepper is the fruit of the plant. All botanical fruits (of which bell peppers are an example) are developed from the plants ovary- making them as definitively female as I can imagine. The whole complex of female plant parts, including the ovary, is called the Gynoecium. Most fruits that we eat come from "perfect" flowers, meaning each flower has male and female parts. Fruit_anatomy also has some good descriptions. It is true that some plants come in male and female versions, but in that case, the male bears no fruit. Holly is a well-known example of such a Dioecious plant (other popular examples of dioecy are ginko and cannabis). Finally, some plants, like birch have both sex organs on a plant, but each individual flower can be male or female. If you want to get more into the details of how all this works, see plant reproductive morphology. SemanticMantis (talk) 20:24, 1 May 2014 (UTC)

I will add that in my WP:OR experience, smaller peppers tend to have fewer lobes, and tend to be firmer. SemanticMantis (talk) 20:25, 1 May 2014 (UTC)

More WP:OR - in my experience, it seems that the number of lobes varies by the colour (green, red, and yellow ones have four, orange ones have three), which suggests that it varies by cultivar or variety. It wouldn't surprise me if peppers from another farm or another country would break down differently. Matt Deres (talk) 16:43, 2 May 2014 (UTC)

May 2

Did the Inflationary epoch create time?

As we all know, the arrow of time is driven by the growing spread of quantum entanglement. Since any Cosmic egg would be fully entangled, it would be a state where no forward motion in time could occur.

Ergo it was the Inflationary epoch when the universe got dis-entangled that laid the groundwork for Entropy's clock, and no time could have occurred during any previous hypothetical fully connected phase.

Hcobb (talk) 03:55, 2 May 2014 (UTC)

We do? It was? Eh? It would? I don't see that at all, however using Paradoxes of material implication I think I would have to agree that your conclusion does follow your premises. Dmcq (talk) 09:07, 2 May 2014 (UTC)

You don't really seem to be asking a question here, but rather trying to persuade us of a handful of highly questionable cosmological claims. AlexTiefling (talk) 09:14, 2 May 2014 (UTC)

The arrow of time article doesn't mention the word "entanglement". However, entanglement does mention this idea, citing [14]. Unfortunately, I don't think I know anything about quantum physics that isn't in Wikipedia, and half of that people will say is wrong when it's discussed here. Wnt (talk) 12:05, 2 May 2014 (UTC)

If we've got it wrong let's straighten it out, but it's the first solidish looking theory anybody's had to explain where time comes from.

Perception of time => Entropy => Quantum entanglement => Initial non-entangled state.

Hcobb (talk) 12:31, 2 May 2014 (UTC)

You're second => does not follow, really. Also, your initial question treats time as a "substance" It isn't. --Jayron32 12:34, 2 May 2014 (UTC)

You're clearly not the first person to propose a theory of time. Don't give yourself airs. Come back when you've spotted the contradiction in your original proposal. AlexTiefling (talk) 12:43, 2 May 2014 (UTC)

No, don't come back, unless you have a question to ask. This is not a place for debating issues or propounding theories, and the above editors should not have engaged the OP. -- Jack of Oz ^{[pleasantries]} 12:48, 2 May 2014 (UTC)

Did been in a time of a virtual realism a time been during as in a real time?--Alex Sazonov (talk) 12:50, 2 May 2014 (UTC)

Huh? What is the Russian text for your question? It makes no sense in English. Edison (talk) 13:36, 2 May 2014 (UTC)

It doesn't in Russian either, remember? InedibleHulk (talk) 02:28, May 4, 2014 (UTC)

I don't think the problems mentioned here are going to be solved this way. Count Iblis (talk) 18:05, 2 May 2014 (UTC)

Did been in a time of a virtual realism had been a time distortion or it been only in a real time?--Alex Sazonov (talk) 06:06, 3 May 2014 (UTC)

Backup CF card

When travelling, I used to back up pictures from a CF card to a portable hard disk like this one. This worked perfectly also in remote places. Now I am planning a trip to a country where there is free wifi at every corner (or at least at any hotel) and I was wondering whether there is a better (smaller/fail proof) solution that allows me to upload the pictures to a server (e.g. my own server). Maybe something that connects to a smartphone or a standalone wifi/card-reader device? bamse (talk) 09:19, 2 May 2014 (UTC)

If your phone has USB OTG you may be able to just plug your CF card into a cheap USB CF card reader, then plug the card reader into the phone. Main issue is whether the card consumes more power than the phone can supply. This question should actually be on the computer reference desk, by the way. 70.36.142.114 (talk) 14:02, 2 May 2014 (UTC)

Water in solar system planets

If some comets are made up of water, and if they collide with planets every now and then, isn't it obvious that at some time they have collided against any planet in the solar system and therefore, there is water in any of them? Maybe the smallish monds won't have enough gravity to keep it, but how could giants as Jupiter or Mars lose it? OsmanRF34 (talk) 13:26, 2 May 2014 (UTC)

Indeed, there's plenty of water on both Jupiter and Mars (Frank Sinatra singing in my head there...). I might be wrong, but I don't think there's a single planet or minor planet that has been shown to be entirely devoid of water. Fgf10 (talk) 13:32, 2 May 2014 (UTC)

I thought it was considered surprising when water was discovered on earth's moon. Of course water-bearing stuff hits the moon now and then, but one would expect the water to evaporate on exposure to the sun. The moon's known water (iirc) is at the poles, where the sunlight exposure is minimal, and I think Mars's water is the same way. 70.36.142.114 (talk) 14:05, 2 May 2014 (UTC)

Does evaporation defy gravity? Water cannot escape the Earth's atmosphere that way, so why should it escape the moon?--Shantavira|^{feed me} 14:30, 2 May 2014 (UTC)

For the same reason there's so little helium (second most abundant element in the solar system!) in Earth's atmosphere. Or, for that matter, why there's so little of anything in the Moon's atmosphere. TenOfAllTrades(talk) 14:40, 2 May 2014 (UTC)

See atmospheric escape. The Earth loses water all the time - or the hydrogen part of it anyway. (We should be ok for drinks until the Sun goes nova; there is water inside the Earth, and geological processes bring it up at roughly the same rate it is lost to space.)

Incidentally, we have an article on origin of water on Earth - it's not as clear cut as SimEarth taught us. 88.112.50.121 (talk) 15:11, 2 May 2014 (UTC)

Excellent read. Who would've thought that the molecules are literally wikt:hightailing it? MIND = BLOWN. - ¡Ouch! (^{hurt me} / _{more pain}) 08:51, 6 May 2014 (UTC)

Water can also hide below the surface, where permafrost may keep it frozen there for millions of years. But one question is if life can start when water only exists frozen below the surface. Another question is if people can extract that water efficiently for a colony there. We certainly need to become far more efficient at recycling water, too. No more flushing it down the toilet or draining it from the tub and forgetting about it. StuRat (talk) 15:34, 2 May 2014 (UTC)

Plant Intelligent/ brain theory

Charles Darwin first proposed that plants root system was a "brain-like" organ and a few studies have been done on plant intelligence. The question is 1. is the science sound enough to be put onto Wikipedia, and 2. should it get its own page or be a section on the plant page. Manofgun (talk) 14:17, 2 May 2014 (UTC) forgot to log in

See articles Plant intelligence and Hormonal sentience. 84.209.89.214 (talk) 15:26, 2 May 2014 (UTC)

I don't think any scientists argue that plants are intelligent, just that they mimic intelligence. For example, the roots will move towards a source of water or nutrients, but that doesn't require intelligence, unlike when people move their village from a dried up well to a good one. In the case of the plant, it could be as simple as those parts of the roots which get all the water and nutrients they need subsequently growing, while those roots which lack those ingredients withering. StuRat (talk) 15:25, 2 May 2014 (UTC)

( Yeah, well you obviously didn't spend to much time looking things up here, did you? Suffice it to say this is a huge topic in modern botany. Please don't be the second responder when you don't know much about the topic, and have no references to cite ) SemanticMantis (talk) 18:03, 2 May 2014 (UTC)

(Obviously, don't criticize a post unless you can prove where that post is in error. StuRat (talk) 16:13, 4 May 2014 (UTC) )

Oh thanks, when I googled it, the plant intelligence thing didn't come up. — Preceding unsigned comment added by Manofgun (talk • contribs) 15:44, 2 May 2014 (UTC)

Read this, and everybody have a toke Template:Toke. :) The mechanism must be ... something wonderful. Wnt (talk) 16:09, 2 May 2014 (UTC)

A scientologist (that's close isn't it?) thought so. The claim made at the time was that the tomato reacted electrically in anticipation of the nail. 84.209.89.214 (talk) 18:02, 2 May 2014 (UTC)

Sure, plants have "intelligence", insofar as they react to environment, make "choices", communicate with each other, etc. They can also cooperate or fight with other plants (allelopathy), forage for food, and exhibit tons of behaviors that we would readily see as signs of intelligence in other organisms. Just remember that this is a fairly metaphorical perspective. I don't think that plants have thoughts, but I don't think insects to either. And insect intelligence is well accepted. In addition to 84's good links above, See plant perception_(physiology), Plant_disease_resistance#Signaling_mechanisms, Phytosemiotics, and links therein. There's even a whole professional society for plant neurobiology [15]. Here's a nice article titled "Simple models of plant learning and memory", that talks about " intelligent responses to complex environmental signals" [16]. So, to answer your questions 1) Absolutely, as long as you can include references to WP:RS. 2) plant intelligence is the main article, but links between all these topics would work well, e.g. in the "see also" section of each article. SemanticMantis (talk) 18:03, 2 May 2014 (UTC)

While Mantis is clearly biased by his fealty to his plant overlords, the distinction he makes is an important one; certainly plants are not capable of cognition, as this process arises from discrete and highly specific biophysical processes known only to originate in certain tissues that plants lack, with no other alternative mechanisms for the phenomena ever suggested in serious modern scientific research; although, of course, it is postulated that the same or similar processes could be replicated in other materials aside from those they are known to occur in, they do not occur in any known plant matter. However, "intelligence" is a broad concept that, depending on context, can include most any of a complex organism's environmental responses. Historically, the term has not always been as applied to plants so readily as animals, owing in part to the speed of external (that is, typically mechanical) responses to such stimuli, but plants have a wide array of mechanisms for sensing their environment and adjusting their growth, movement, and other functions appropriately. Snow talk 21:04, 2 May 2014 (UTC)

Also worth noting that our articles in these areas are a bit of a mess. E.g. Cognition is defined in a way that make it unique to humans (via language), despite our article at animal cognition (and animal language for that matter). Maybe less contentious than "cognition" or "intelligence" is "information processing", and plants clearly do that (though that article is also a mess, btw). Anyway, I think you're right about historical biases, us naked apes like to think we're quite special. And of course it is only recently that we have the tools and conceptual understanding to demonstrate how plants communicate, make decisions, etc. SemanticMantis (talk) 21:32, 2 May 2014 (UTC)

You're quite right that our articles on the pheneomena of thought (or at least those which focus on the empirical etiology as opposed to pure philosophy) are all over the place in some respects (there's always more room at WP:WikiProject Cognitive Science if you would like to collaborate!), but I'm of two minds on whether or not that narrowness with which we treat cognition in some of the afore-mentioned articles is inappropriate; on the one hand, I'm a big proponent of animal precursors to "uniquely" human mental traits - on the other, the division you reference which utilizes dependencies on language, visual processing, and a handful of other mental constituents of cognition is fairly well-reflective of our sources and the current treatment of such issues within scientific literature broadly. While certainly it's foolish to insist non-human animals are incapable of thought, including such capabilities as causative association and complex planning, other abilities in the human mental repertoire, such as abstraction and other aspects of reasoning, are (I think reasonably) felt to be largely the purview of humans (or at least humans and our near relatives) linked to specific neurophysiological and proto-cognitive traits. This emphasis is partly due to the influence of evolutionary psychology, which lately has begun to have a huge impact on the way the cognition is perceived (and rightly so, in my opinion), although its worth noting that leading names in this field are themselves very cognizant of the chicken-and-egg complexities of linking cognition with language and other forms of mental symbolism. And of course EP is quite preoccupied with trying to determine which of the mental and physiological precursors of our ancestors led to the development of our unique psychological qualities. Anyway, returning to plants, as you say, information processing presents a useful distinction; ecophysiology is also useful in this regard, though it also preserves the dichotomy between Plantae and Animalia in regard to stimulus response. Snow talk 22:07, 2 May 2014 (UTC)

Maintain Hot Water

When I travel I have been lowering the temperature on my water heater. Is this necessary?

Does it take more energy to maintain a higher temperature than a lower one?

I know it takes more energy to achieve higher temperatures but, once achieved, does it also take more to keep them there?

Thank you — Preceding unsigned comment added by ChrisIsFromCanada (talk • contribs) 14:38, 2 May 2014 (UTC)

To maintain the temperature of something, you have to put in as much heat energy as it is losing. How much heat energy something loses is proportional to the difference in temperature between that thing, and the things around it. Hotter water loses more heat energy to its surroundings than cooler water, because there is a bigger difference between the temperature of the hot water and the temperature of the surroundings.

So, if your water heater is actually keeping a volume of hot water perpetually hot, then it will take more energy to keep it at a higher temperature. However, is this actually what it does? When you travel, does your heater at home really keep a tank of water hot for the whole time you're away? If so, do you really want to use that water when you get back? 86.146.28.229 (talk) 15:12, 2 May 2014 (UTC)

Sure, storage water heaters are the usual kind in Canada. And you're not going to drink the hot water, so any slight contamination due to leaving it standing for a few weeks is really no big deal. --50.100.193.30 (talk) 02:51, 3 May 2014 (UTC)

It makes a huge difference if it's winter or summer, since the heat which is lost all goes into the basement or utility room where the water heater is located, and eventually migrates to the rest of the house. In the winter, this isn't bad at all, and may even save you money, if your water heater is natural gas and your home is heated by electricity. In summer, on the other hand, not only do you lose the energy at the water heater, but your air conditioner will need to work more to keep the house temperature down. Of course, if you turn the A/C off when gone (which makes sense unless you have pets that would suffer), then that part doesn't apply. However, we're probably only talking pennies a day, in any case, so you decide if it's worth the trouble. StuRat (talk) 15:22, 2 May 2014 (UTC)

(ec)In real systems with imperfect insulation (i.e. all of them), yes, energy loss grows with the temperature difference between the warmer and the colder body. In systems where energy loss is dominated by heat conduction, and if I remember my undergrad physics correctly, energy loss is proportional to the temperature difference. So from an energy usage point of view, it's best to turn the heating off completely if you are away for a while. At least in Germany, however, the recommendation is to keep any warm water reservoir at at least 60°C, to eliminate the risk of Legionella. So either turn the heat off completely (to allow cooling below 25°C), or keep your heater at at least 60°C. --Stephan Schulz (talk) 15:27, 2 May 2014 (UTC)

However, in winter, there's also the risk of pipes freezing and bursting. To avoid this, keeping the water heater on high and letting the faucets drip may work. Although this is wasteful of both water and energy, it's less expensive than a water leak in the walls. StuRat (talk) 15:39, 2 May 2014 (UTC)

If freezing pipes during an absence are a concern, it's best to shut off the main water valve and drain the pipes by leaving the faucets open (and draining the water heater, which will have its own drain valve). On this page, for example, see the "When your home must be abandoned" section. But they're talking about situations where a power or other utility outage may shut down your heating system. In a properly heated house with the pipes properly insulated, they shouldn't freeze. But, of course, you never know what emergency may arise during your absence. --50.100.193.30 (talk) 02:51, 3 May 2014 (UTC)

Draining all the water out of all your pipes is a major operation, possibly involving disconnecting pipes, so not something you will want to do when just going away for vacation. StuRat (talk) 23:27, 3 May 2014 (UTC)

It's usually enough to just turn the water off at the mains and leave a few of your faucets open, particularly the lowest one, if you have one in the garden or something. You don't need to evacuate ALL the water from the plumbing, just leave enough room so that expansion of the remaining water doesn't burst the pipes. Vespine (talk) 23:17, 4 May 2014 (UTC)

Rhizobium spp. for pea/beans vs. clovers/alfalfa ?

My local garden centre sell Pea & Bean bacteria, without specifying which species of bacteria it is, only that it is for Phaseolus vulgaris, Phaseolus coccineus, Pisum sativum, and Vicia faba. Is the species of rhizobium for these peas and beans also suitable for clovers (specifically red/crimson and white) and alfalfa/lucerne? CS Miller (talk) 15:36, 2 May 2014 (UTC)

I'm sure that that product can't hurt clovers or alfalfa, and would likely help them just fine. My guess based on similar products is that there is a mixture of spore in that product, not just one type. There are several types of rhizobia, and some have a high degree of host specificity. This page lists some species pairings [17]. It seems to me that at least some microbes can nodulate all the species you list, but I don't have the time to go through it carefully. It would make sense for a commercial product to feature a mix of different generalists... These papers say that some plants and microbes have high specificity, and talk a bit about effectiveness [18]. [19]. SemanticMantis (talk) 18:22, 2 May 2014 (UTC)

Unless you're a commercial farmer who frequently spays with glyphosates and things, then I don't see the benefit of using any inoculation booster. There should be a sufficiently broad spectrum of these little bugs in the soil for the host to pick and choose from. For the commercial farmer there is a need for boosting because glyphosates inhibit the same metabolic pathway that most plants/weeds have (thus killing them) and so makes the soil very deficient in nitrogen fixing bacteria. --Aspro (talk) 22:14, 2 May 2014 (UTC)

Yeast vs bacterial culture

Is yeast culture much different from bacterial culture? Are yeast cells more fragile? There's an assay I'd like to do in yeast but I don't know whether it's worth the extra effort, if there is any. It looks similar but I say this with no experience beyond E. coli DH5-alpha. — Preceding unsigned comment added by 129.215.47.59 (talk) 18:03, 2 May 2014 (UTC)

Wikipedia has articles about Yeast and bacteria that you can read on your own. While both are single-celled organisms, they are not closely related at all. Yeast are eukaryotes and bacteria are prokaryotes; as evolutionarily speaking that was one of the earliest splits in the living world, the Most recent common ancestor of the two is VERY far in the past. You are literally a closer relative to any yeast than the yeast is to any bacteria. --Jayron32 18:08, 2 May 2014 (UTC)

I think a misunderstanding has occurred. My question does not pertain to how different bacteria and yeast are. I want to know how different the techniques used to culture them (in a lab) are. 129.215.47.59 (talk) 20:17, 2 May 2014 (UTC)

Think Fermentation in food processing might be more appropriate.--Aspro (talk) 21:16, 2 May 2014 (UTC)

What? No! I'm talking about a laboratory experiment. I want to culture them in small volumes (<1 litre) and on petri dishes. 129.215.47.59 (talk) 21:54, 2 May 2014 (UTC)

I'm not sure how much you might already know, but here are two descriptions of methods for yeast cultures in the laboratory [20] [21]. Seem that the techniques are similar to those for bacteria, but different. Beyond that, talk to your lab adviser or mentor. SemanticMantis (talk) 22:31, 2 May 2014 (UTC)

Fine. What strain of yeast or bacteria? They grow best, if conditions closely match their particular niche. Just as agar-agar in your Petri dish may require the addition of some beef stock or for aerobics a pinch of ascorbic acid etc. There is no universal method that suits all. Then there is the temperature to think about, some are thermophilics (like those you find in a steaming heep of horse dung), others (like those that bottom ferment larger) like cooler temperatures. Thats why labs have incubation ovens with an adjustable thermostat. --Aspro (talk) 22:34, 2 May 2014 (UTC)

Thinks to myself : “what lab experiment involving yeast is worth the effort”? Answer: Producing a litre of Saccharomyces culture to inoculate a malted wort to produce 3,000 gallons of brew to be distilled into some fine single malt whiskey. That to my mind would be worth the effort. Hmm, does the original poster have any distilleries in the country were he lives?--Aspro (talk) 22:58, 2 May 2014 (UTC)

Like. --Jayron32 23:36, 2 May 2014 (UTC)

My lab works with both bacterial and yeast cultures. The yeast cultures do not seem to take any more effort to grow than the bacterial cultures, except that they require different nutrition and different temperatures. So aside from minor details, the culturing protocols seem markedly similar. Someguy1221 (talk) 06:39, 3 May 2014 (UTC)

However, you must make yourself comfortable with the fact that since you are likely raising yeast on yeast extract, you are encouraging cannibalism. Someguy1221 (talk) 06:51, 3 May 2014 (UTC)

Image focus distance of relaxed eye lens

Human eye - click for full article

Eyes can be "rested" by closing them or focussing on a distant plane. At what distance does the human eye lens [muscles] become fully relaxed? --Seans Potato Business 21:58, 2 May 2014 (UTC)

Infinity (approximately)--109.151.101.168 (talk) 23:19, 2 May 2014 (UTC)

Yes. An eye that needs no correction for myopia (near-sightedness), hyperopia (far-sightedness) or presbyopia (the loss of focusing range during aging) when relaxed is focussed on infinity. It focuses when needed on close objects by the ciliary muscles 3 surrounding the lens contracting. This narrows the diameter of the ciliary body 4, relaxes the fibers of the suspensory ligament, and allows the lens 10 to relax into a more convex shape which better focuses divergent light rays onto the retina. 84.209.89.214 (talk) 23:26, 2 May 2014 (UTC)

Detail: presbyopia doesn't affect the far point. --Tardis (talk) 23:32, 2 May 2014 (UTC)

Note however that the resting focus of accommodation or dark focus is not the same thing as total relaxation of the ciliary muscles. --catslash (talk) 01:31, 3 May 2014 (UTC)

Did been a mirrors in the dark? That’s why, a eyes always been relax in the dark!--Alex Sazonov (talk) 06:39, 3 May 2014 (UTC)

Cats eyes are different, see Tapetum lucidum. 192.249.63.59 (talk) 07:28, 3 May 2014 (UTC)

If been a mirrors in the dark a optical effects must been seen another! A cats always had been another optical sphere in their eyes than had been a man.--Alex Sazonov (talk) 07:44, 3 May 2014 (UTC)

Almost are not been a refraction of light in the dark.--Alex Sazonov (talk) 07:57, 3 May 2014 (UTC)

I been thinking that a cats always had been a monochrome vision and they cloud been see a colors in bright.--Alex Sazonov (talk) 08:23, 3 May 2014 (UTC)

The article Dichromat has references to support its assertion that while their Triassic ancestors were trichromatic, placental mammals such as cats have lost the ability to separate green and red, and have become dichromatic. Dichromatic vision may improve a cat's ability to distinguish colours in dim light, though how is unclear. 84.209.89.214 (talk) 11:43, 3 May 2014 (UTC)

Thanks much!--Alex Sazonov (talk) 11:56, 3 May 2014 (UTC)

May been a electromagnetic induction in the light and in the dark always been different, thats why a optical effects in the light and in the dark always are been different?--Alex Sazonov (talk) 09:37, 3 May 2014 (UTC)

I don’t know but may been done a vision seen focus of a electromagnetic induction to been see it?--Alex Sazonov (talk) 11:37, 3 May 2014 (UTC)

Silicagel (orange to clear indicating) high temperature

I accidentially regenerated orange indicating silicagel in the hot air oven at 200°C, but later read that one should only dry it at 130°C at most. It produced a kind of weird smell, but looks like it is still working. Is it dangerous? Does that release any toxic components in the air? Or release any toxic componenets in the oven(I use the same oven for food)?

best thanks --helohe (talk) 23:39, 2 May 2014 (UTC)

You shouldn't rely on Refdesk answers for advice regarding your safety. In any case, it would be very hard to give such advice without a specific product and manufacturer indicated. Which brings us to the main point that it would make more sense to ask them. Wnt (talk) 23:47, 2 May 2014 (UTC)

May 3

Did been a quantums in a low temperature?

Did been a mirrors in a mirror glass after it been very colder?--Alex Sazonov (talk) 06:29, 3 May 2014 (UTC)

I think Alex is asking whether mirrors continue to reflect images normally when at temperatures low enough that strange quantum effects tend to occur. Someguy1221 (talk) 06:36, 3 May 2014 (UTC)

May been it a electromagnetic effect?--Alex Sazonov (talk) 06:46, 3 May 2014 (UTC)

парень, кончай троллить. или учи иглиш Asmrulz (talk) 13:28, 3 May 2014 (UTC)

инглиш, не иглиш 24.5.122.13 (talk) 19:15, 3 May 2014 (UTC)

Consider doing a double slit experiment with freely floating mirrors behind each slit. If the phton goes through one particular slit, it will be reflected off the mirror behind it, so that mirror will gain some momentum. Nevertheless, you will stil get an inteference pattern, because the width of the wavefunction of the mirror in momentum space under normal circumstances, is much larger than the change in the momentum. The interference pattern will only vanish if the mirror can evolve freely without any interaction from the environment. The wavefucntion of the mirror in ordinary space can then become arbitrily wide so that it can get a momentum that so sharp that it would cointain the which way information about the photons. Count Iblis (talk) 21:20, 3 May 2014 (UTC)

Thanks more. May been a electromagnetic induction always been doing another properties of it in a very cold? That’s why it is been seen always another optical effects! May be it?--Alex Sazonov (talk) 08:57, 4 May 2014 (UTC)

If been a conductor in a very cold a electromagnetic induction of it always been done another than it been done without a coldering.--Alex Sazonov (talk) 10:35, 4 May 2014 (UTC)

The myth of endodontic pain

There is a persistent myth (even communicated to me by my own parents when I was young) that endodontic therapy, commonly known as a root canal, is extremely painful. I find no shortage of sites exclaiming that this myth may have origins in some vague past before modern methods or modern anesthesia rendered the procedure painless (here is one such example). But what I'd like to know is precisely when root canals ceased to be painful as generally practiced in the United States. It's my understanding that anesthesia has been regularly used in dentistry for a very long time, certainly too long for my own parents to have grown up without it (though perhaps they heard horror stories from their own parents or grandparents). Someguy1221 (talk) 06:49, 3 May 2014 (UTC)

Well, I've had root canal treatement and it certainly was painfull. And very uncomfortable as well as painfull. As any treatment involving drilling teeth often is. Now, sometimes the aneasthetic works well, sometimes it doesn't work well, and sometimes it doesn't work at all. That's because the use of local aneasthetic to deaden teeth is not a simple affair. It depends on which tooth (some are easy to deaden and some are not), it depends on the person - not everybody has the nerves routed in quite the same way, it depends on the skill of the dentist, and it depends on the patience of the dentist. For me, it seems that the maximum amount of pain deadening comes about 20 minutes after the injection, and begins to wear off in about another 20 to 30 minutes. Since root canal treatment can take up to an hour to complete, it is at least damn uncomfortable. I had one dopey dentist once who simply would not wait the initial 20 minutes. General anaesthesia, its cost and its risks, is just not justified in dental surgery, except in very specail cases, e.g., when the patient is mentally retarded and simply will not put up with a bit of pain and discomfort, and won't stay still for the root location process. Local anesthetic for dental surgery is so poor, nor forgetting the "slobbery lips" feeling long after the procedure is finished, that for straitforward filling repair on teeth difficult to deaden, I tell the dentist to forget about the needle and just get on with it. It hurts, but as soon as he's finished, there is no pain, no discomfort, no slobbery lips, and no worries about whether your bite closes properly.

The web site cited by Someguy is somewhat dubious. For instance it claims that root canal work does not kill the tooth. Well, root canal work involves removing all living tissue from the tooth - pulp, blood vessels, nerve, everything. There's nothing left that's alive, only the dead enamel and the filling or crown. It's a bit like saying removing the soft tissues from a finger, replacing them with Araldite, and saying that that doesn't kill the fingernail, which was always dead anyway.

1.122.161.156 (talk) 08:07, 3 May 2014 (UTC)

Actually, a number of oral surgery procedures regularly use general anesthesia today. On a separate point, variation on reactions to local anesthetics is unlikely to have much to do with variation in innervation of the relevant tissues but rather the patient's metabolic response to the anesthetic employed. Snow talk 08:20, 3 May 2014 (UTC)

Regarding nerve routing vs metabolism - not according to the several dentists I've had over the years. 1.122.161.156 (talk) 08:26, 3 May 2014 (UTC)

But if they remove the nerve, where does the pain come from? Count Iblis (talk) 21:12, 3 May 2014 (UTC)

One can imagine that it may well hurt WHILE they are removing it. In any case, normal drilling out to get a decay-free interface for the filling to bond to hurts, and they aren't even touching the nerve. It's the drill vibration transmitted through the tooth that hurts. The ultrasonic/high frequency tool they use to get rid of plaque cannot be felt. But I seem to recall than the nerve inside a tooth is not a pain nerve, it's a pressure sensor. The nerve contributes nourishment to the tooth in some way not well understood. The pain nerves are in the surrounding bone and flesh. 1.122.161.156 (talk) 01:43, 4 May 2014 (UTC)

It's also possible for a absent nervous tissue to contribute to pain, since it is more the complex associations between nerve cells, rather than the properties or state of particular individual cells, from which the sensation of pain arises. Phantom pain is the most obvious case, but there are plenty of other pain phenomena, such as referred pain, wherein pain is perceived in a part of the body where no nocireceptor is actually firing. But that bit about the nerve contributing nourishment in nonsensical; nervous tissue has no mechanism for supplying nutrients to any organ or structure; that is the function of the circulatory system, which is made of quite distinct tissues. You may be thinking of the blood vessels which feed into the dental pulp, which is innervated for pain detection, though the other tissues you mention are involved in this respect as well. Snow talk 02:02, 4 May 2014 (UTC)

Are you sure that the nerve does not contribute to nourishment? Due to us being evolved creatures, our bodies are full of examples where something has been utilised or co-opted to do something diffrent or additional to its original or prime function, sometimes in a way that has been difficult for scientists to identify. For example, the fat around the heart contributes essential metabolytes for heart function - this has only recently (~~10 years or so) been discovered. It used to be thought that estrogen was made only in a woman's ovaries. But it was noticed that removing ovaries usually had little effect on breast cancer (the most tumour common types require estrogen to grow), and breast cancer is usually more serious in fat women. The, from about 40 years ago they thought that body fat stored estrogen. Now it is realised that fat makes estrogen. I googled "function of nerves in teeth". This threw up numerous sites typically saying "the nerve is essential to the growth of teeth" but unfortunately I found no site that said how it is essential. Cells in the deep areas of the brain supply essential metabolytes to outer areas of the brain (eg dopamine). It used to be thought that the heart's function was purely mechanical - pumping blood. Now it's known that it secretes a signalling hormone that increases kidney excretion rates. 1.122.161.156 (talk) 03:25, 4 May 2014 (UTC)

Though not marked in this diagram, the apical foramen is the opening between the tooth and surrounding connective tissue through which both vascularization and innervation of the pulp are accomplished.

Without a specific mechanism suggested, it's impractical to try to refute a vague suggestion of a connection, but that doesn't mean we have any evidence for it's existence to begin with. It's also unnecessary: we already know how the tooth gets it's nutrition: blood vessels that enter the pulp through the same structures as the nerves themselves.

Some of the cases which you note above are mischaracterized, but in any event none of them are analogous to the situation suggested wherein a tissue type designed to propagate electrical signals via action potential could achieve the distinctly different function of the fluid-carrying structures of the circulatory system. That would be like attempting to co-opt the wire and circuits of your TV to conduct water to your dishwasher; they are designed for drastically different ends. It is true that the nerve is important to the health of the tooth, as it provides us with necessary feedback as to when to when pressure, temperature or impacts are exceeding healthy limits, or otherwise we'd surely damage them (in the way that those who lack sensation to any area of the body are at drastically increased risk of injury to those areas) or may fail to notice dangerous infection. Elsewise we wouldn't have those nociceptors, thermoreceptors, or mechanoreceptors in the tooth to begin with. Snow talk 05:15, 4 May 2014 (UTC)

I agree that an assertion that something is possible does not make it true. However much of what else you wrote isn't right. My example of deep brain cells making dopamine for higher function brain cells to use is just such an example of something originally evolved to do one thing (sensory/motor signalling) being co-opted to do something else. To use your TV analogy, sure, a TV cannot supply water. But it can supply heat for the comfort of your small pet, if you have one, or help heat the room - that is a better analogy. TV sets are not designed for the pupose of emitting heat, but they do it anyway, and the heat can be usefull. Clearly, the nerves in teeth are there to sense pressure, and they also sense temperature. Those priomary functions do not preclude an additional function, just as fat cells(evolved primarily to store energy) around the heart has evolved to supply certain metabolytes needed by the heart. 1.122.161.156 (talk) 06:22, 4 May 2014 (UTC)

That argument is a bit of a non-sequitur., if you'll forgive me saying it. My choice of an electrical appliance and a plumbing process for that analogy was not arbitrary. We are talking about structures with vastly different forms and functions. The problem I am having with your assertions here is that they are quite vague - you're insisting upon a causative link here, but not describing the hypothetical mechanic through which it would be achieved at all, so that leaves little to discuss. I can only tell you how these tissue types operate in general and that I see no way in which peripheral nerves -- basically self-mediating conductors in this context -- can perform the tasks of vascular/circulatory structures in transporting nutrients to other tissues. If you would like to provide the sources which initially caused you believe they served in this role, their wording would be at least something that we could discuss, but as regards physiological mechanisms which have been validated or even just suggested in genuine research, I know of no sources suggesting such a role for maxillary nerves, nor would I expect to learn of one. On another note, it is not uncommon for neurotransmitters, such as dopamine, to be produced by discrete cell types which then utilize it in their own synaptic function or produce it as part of the metabolic pathway for the synthesis of still other neurotransmitters; this latter function seems to be the one you've been referencing (dopamine is a precursor to norepinephrine and epinephrine) but this is not a good example of an extreme adaptation, relevant to the context, since many types of brain cell have similar functions relative to their neurotransmitters. Snow talk 11:12, 4 May 2014 (UTC)

What your dentists are talking about is not "nerve routing" (by which I took you to mean some general principle of interconnectivity); they're talking about the nerve morphology and proximity to the area upon which they will have to work. An oral/maxillofacial surgeon's chief concern with the nerves is avoiding damaging them during surgery on surrounding tissues (or when administering local anesthetic) so as not to impair function and sensation. [22]. Imaging is also helpful in determining whether to advise surgery when considering a problem tooth or other condition that stands to cause an impact upon the nerve. Don't get me wrong, additional innervation means more potential for something to go awry, but it doesn't directly influence the efficacy of the anesthetics or cause certain people more pain, unless there's a blunder. Those types of claims are difficult to validate, when you consider that 1) Pain is hard to empirically quantify in a useful way in studies, with some exception for brain imaging 2) most procedures of this nature have historically not used real-time mapping and most still don't, so the correlation would be hard to establish for someone not set out to do just that. In any event, a local anesthetic should be able to inhibit activity in a good area anyway, and if it's not working to that effect, you still must explain the physiological mechanisms for that fact, regardless of the gross morphology of the nerve. Those effects, that is, the agonism of the pharmaceutical employed, is mostly empirically treated on a much smaller scale. Snow talk 00:58, 4 May 2014 (UTC)

No, I've had this discussion with a few dentists - they made it clear that the location of nerves varies from person to person. And the article you linked to says the same thing - in the the 2nd para it says "Due to this nerve's variable anatomical location, it may ..." and under the heading ANATOMY OF THE LINGUAL NERVE IN THE THIRD MOLAR REGION it discusses the variability in detail.

I'm in my 70's and over the years I had to change dentists about every 1o years or so due moving to new towns, the dentist retired, etc. The first time a dentist begins to do a filling on me, he typically goes "I'll give you an injection, so it won't hurt."

I'll say "No don't - I've learnt from experience that anaesthetics don't work well. Just forget the needle and get on with it."

Dentist: "It's easier to work on a patient that is relaxed. I have a newer, better, anaesthetic than your old dentist was using. I'll give you a jab." Prodeeds to inject the anaesthetic. Waits 5 minutes. Asks "Your jaw's numb now isn't it?"

Me: "No". Dentist waits another 5 minutes.

Dentist: "It must be working now." Touches my lip. "Feel that?"

Me: "Barely. Doesn't feel normall."

Dentist: "Ah, it's working now. I'll begin. You can't feel anything." Pokes about inside my mouth. Suddenly there is pain - feels like he poked my jaw with a sharp instrument. It doesn't hurt much, but because it was unexpected, I jump.

Dentist, aside to nurse: "Heck, he can feel that!" Waits another 5 minutes. Repeats poking/jabbing. I jump again. I tell him to stop stuffing about and get on with it. Some dentists are smarter than others. Some do a better job than others. They vary quite a bit.

1.122.161.156 (talk) 02:10, 4 May 2014 (UTC)

Yes, of course the exact nerve morphology varies -- not drastically, but it does -- they are different individuals. That's like saying that individuals have blood vessels (or really any other anatomical feature) of differing sizes; we can take it for a given. But that's not really germane to the distinctions I was making. I'm not saying that you don't feel what you believe you feel, or that local anesthetics of various types don't have lower efficacy for you than the average patient, only that the underlying mechanisms are a little different than what was described. Snow talk 02:25, 4 May 2014 (UTC)

Why are physics texts often lax with integral notation?

I've found that not only Wikipedia, but both my physics textbooks, omit the domain of integration and/or limits of integration for integrals such as in Maxwell's equations, a practice I personally find disagreeable. Although there usually is a sentence along the lines of "The integral is taken over..." following, there isn't always. In contrast, my math textbooks are very adamant about being clear about limits of integration, i.e. they would write no such thing as $I=\int r^{2}dm$ but instead $\iiint _{Q}r^{2}dm$ or with one integral sign, $\int _{Q}r^{2}dm$.--Jasper Deng (talk) 10:24, 3 May 2014 (UTC)

It is quite normal in maths to leave out all the assumptions in an equation and just leave the important bits. Otherwise sometimes you wouldn't see the important bits easily. Without the limits an integral is called an Indefinite integral and you're expected to stick in your own limits for your particular case. Dmcq (talk) 10:43, 3 May 2014 (UTC)

This is actually part of why I dislike the practice, because an indefinite integral denotes the family of all antiderivatives of a function. Not only does this not apply for functions of more than one variable (there is no notion of a multiple indefinite integral, except perhaps potential functions written like $\int \mathbf {F} (\mathbf {x} )\cdot d\mathbf {x}$ for use with the gradient theorem), but in nearly all cases where the limit is omitted, with the notable exception of potential energy and other potential functions, a definite Riemann sum is implied.--Jasper Deng (talk) 18:14, 3 May 2014 (UTC)

Fair enough, so you have an argument for why you feel a different approach should be taken, but you clearly understand the reasoning of the parties who do otherwise as to why they do it, which makes the question in the header (the only question you've asked) purposeless, and thus this seems like more an effort at stating a particular perspective and debating the merits, which is not really our purpose here. If to any extent you were genuinely confused on the matter, I think you've got about as clear an explanation as is available from Dmcq and Count Iblis, so we should avoid turning this into an endlessly recursive discussion about the benefits of one approach over the other as we're not a forum. No offense intended! Snow talk 02:17, 4 May 2014 (UTC)

I mean, I'm pretty sure Dmcq is not completely correct in the assertion that lack of a limit of integration means an indefinite integral, so that can't be the reason.--Jasper Deng (talk) 03:14, 4 May 2014 (UTC)

Note that this is part of a much more widespread habit of those outside the field being more lax when using info from that field. For example, you would expect a survey conducted by a polling organization to include all the details, like the standard deviations, while what gets reported in the media often lacks any such details. StuRat (talk) 12:01, 3 May 2014 (UTC)

In a formal setting, where the integration region is arbitrary anyway, you don't need to specify it. You just need to introduce a convention at the start that you choose not to do so. And it can be argued that being sloppy/lazy is better than being precise with the notation.

In physics you want to focus on the physics and not on the mathematical details. While these details are important, you don't want these to obscure the text. In old books from the 19th century you sometimes find Maxwell's equation written out explicitely in x,y,and z coordinates, while in modern notation we would use the div, nabla etc. operators. Einstein invented the summation over repeated indices convention (a.k.a. Einstein convention) to get rid of all summation signs in tensor equations to make the equations better readable.

Dirac needed a modified definition for the derivative of the logarithm and he chose to violate the mathematical rule for this by inventing the Dirac Delta function, which isn't a bona fide function. It was much later that this was put on a rigorous footing by mathematicions who developed the theory of distributions.

In more advanced physics courses things will only get worse. In quantum mechancis it is customary to write an integration sign even if it can mean a summation (you don't want to be bothered about the distinction between a continuous spectrum and a discrete spectrum if they can be captured in the same setting). Also, you typically don't use the mathematical notation for distributions, you use them as if they are ordinary functions.

When doing perturbation theory, you won't be bothered too much about the fact that the perturbation series actually doesn't converge. As George F. Carrier has pointed out, that's usually not a bad thing: "Divergent series converge faster than convergent series because they don't have to converge." Count Iblis (talk) 21:09, 3 May 2014 (UTC)

I am glad somebody raised this issue. I wish people were more careful with such notations which might be easy for regulars but difficult when you try to comprehend a subject that is way out of your field. --AboutFace 22 (talk) 23:09, 4 May 2014 (UTC)

Matlab

Hi What is the options of taylortool and taylor modulation in MATLAB?محسن قنبرنژاد (talk) 11:50, 3 May 2014 (UTC)

I suggest you move this to the Math Desk. StuRat (talk) 11:54, 3 May 2014 (UTC)

You can find the documentation for the Taylortool at http://www.mathworks.com/help/symbolic/taylortool.html. I have never seen the term "Taylor modulation", and I don't think it means anything. Looie496 (talk) 13:36, 3 May 2014 (UTC)

caffeine in shampoo

I recently saw an advert on TV for shampoo containing caffeine. Is caffeine absorbed through the skin? My guess in answer to this question would be 'no' or 'very poorly'. Even if caffeine is absorbed through the skin, is caffeine good for one's hair? My guess again would be 'no!'. And even if caffeine is absorbed through the skin and it is good for one's hair, (making it shinier or stronger or whatever) is absorbing caffeine through the skin proven to be better for hair than obtaining caffeine through more conventional means, i.e. drinking it? My guess again would be 'no!' Any thoughts? — Preceding unsigned comment added by RichYPE (talk • contribs) 18:53, 3 May 2014 (UTC)

Read these articles: This one and this one come from popular science blogs, and This one comes from a peer-reviewed journal of the British Pharmacological Society so is probably as reliable as you can get, and discusses research into not just that caffeine is absorbed by skin (it is), but also how it gets into the blood through the skin. --Jayron32 18:57, 3 May 2014 (UTC)

I’m thinking, should be bestly for a skin a protein shampoo or a placent shampoo, it they would been more powerful than another!--Alex Sazonov (talk) 19:08, 3 May 2014 (UTC)

Note that they may not be going for an effect on the hair. Since many people shampoo in the morning, they might appreciate the wake up effect of a dose of caffeine. They might market it as "refreshing", etc. Of course, those who shampoo before bed may not appreciate the caffeine. StuRat (talk) 23:22, 3 May 2014 (UTC)

I don’t know but, may been a caffeine is been a tranquilizer or a antidepressant?--Alex Sazonov (talk) 08:06, 4 May 2014 (UTC)

Caffeine is a stimulant. StuRat (talk) 14:06, 4 May 2014 (UTC)

As I been know well, it had been a variations.--Alex Sazonov (talk) 16:36, 4 May 2014 (UTC)

Well, Ritalin is a stimulant, and has the opposite effect in kids with ADHD, but I'm not aware the same is true of caffeine. StuRat (talk) 16:50, 4 May 2014 (UTC)

Here's a blog post (2002) from someone who tried Shower Shock™ caffeinated soap and found no effect. —Tamfang (talk) 17:29, 4 May 2014 (UTC)

Что хуже?

Какая болезнь более опасна -- сонная или кессонная? ;-) 24.5.122.13 (talk) 19:22, 3 May 2014 (UTC)

Never mind, the prognosis sections in the two articles suggest that the first is much more dangerous (despite the fact that the second is much more painful). 24.5.122.13 (talk) 19:29, 3 May 2014 (UTC)

Is it been real a protoplasm electric transformer

Is it been, a real that would been a science project of a protoplasm electric transformer which been powerful transform a powerful electric volts?--Alex Sazonov (talk) 19:33, 3 May 2014 (UTC)

There's no way to get "protoplasm" in a legit topic on electrical engineering using machine translation. Russian and English are not THAT disjoint. Now you're just plain f**g with everybody. If this is some attempt at dada, you're 90 years too late. Asmrulz (talk) 20:49, 3 May 2014 (UTC)

The WP Plasma disambiguation page list both protoplasm and plasma (physics), so confusion of the two is not that implausible. --catslash (talk) 21:22, 3 May 2014 (UTC)

It's not just that, it's... everything. I actually chuckled at "powerful electric volts", it sounds too much like something straight out of Borat. The OP is pulling our leg and he makes Mother Russia look bad. Asmrulz (talk) 22:15, 3 May 2014 (UTC)

True, but I still daydream of modifying the stacked membranes of the electric organ for isotopic enrichment. :) Wnt (talk) 02:06, 4 May 2014 (UTC)

Indeed, Google Translate lists the top two possible meanings of "протоплазма" as "protoplasm" and "plasma". Furthermore, a "plasma transformer" is a "quest item" in the game Fallout 2[23], so the OP appears to be a perfectly legitimate question as to whether plasma transformers exist in real life. Red Act (talk) 03:00, 4 May 2014 (UTC)

Yes, but are also been telephone links to consider. How does one wind up with "bestly"? InedibleHulk (talk) 03:19, May 4, 2014 (UTC)

Will be kindness for me. Is it been a electromagnetic induction always is been a works body of a protoplasm electric transformer?--Alex Sazonov (talk) 07:55, 4 May 2014 (UTC)

Bird song identification, Baltimore MD

For the last week or so, there's been a recurrent bird call in my neighborhood. My google-fu is hopelessly inept. So, I turn to you. It's a three note song, each note sustained with no warbling for about a second. I found a virtual piano app online (at virtualpiano.net), and to my ear, the notes are C-49, E-53, D-51. My girlfriend and I would love to know who's making this noise. Thanks. 76.21.157.67 (talk) 20:06, 3 May 2014 (UTC)

It doesn't quite fit your description, but possibly a whippoorwill? Our article includes an audio sample of their song, for comparison. Looie496 (talk) 03:28, 4 May 2014 (UTC)

Sigh... the tones of a piano seem so different from those of a bird, I can't really get a fix on it. A somewhat similar sound is the Eastern Towhee's "drink-your-tea" song [24] but this is a long shot. Wnt (talk) 05:03, 4 May 2014 (UTC)

Maybe this tool can help. InedibleHulk (talk) 06:16, May 4, 2014 (UTC)

What kind of sound is it? Is there a musical instrument is sounds similar to or does it perhaps sound more like words? Could you approximate it (or some of it) in script? Matt Deres (talk) 12:15, 4 May 2014 (UTC)

Thanks for the assist thus far. I found the site Inedible pointed to before I posted, but since I didn't have any idea how to narrow my search the prospect of going through each individually was daunting. The song is three single notes, whistled straight with no trill. The second note is two steps up from the first, and the third is one step down from the second. It's not the Towhee.2601:A:1480:314:E410:5E00:DE3F:56E4 (talk) 15:15, 4 May 2014 (UTC)

Just click the blue headers ("Sound or song consists of three or more notes"), then use the drop down menu when you're narrow enough. But I'll admit, it didn't help me find my mystery bird, either. I think I need a subsection here. InedibleHulk (talk) 18:03, May 4, 2014 (UTC)

Song Identification, Northern Ontario

Not trying to hijack here, priority goes to 76. But I have a longtime bird neighbour who slowly goes E-E-C#, the last note as long as the first two, then four "nyuks", like Curly Howard. It sounds like a jeering taunt, like you sometimes hear in sports. I only hear him in the early morning (5-9). Who knows this guy? InedibleHulk (talk) 18:03, May 4, 2014 (UTC)

Is your neighbor only present in the late spring and summer, or does he winter over in northern Ontario as well? Pardon me for asking for more details on your location, but where are you, and what's the terrain around you? Kenora District, or Thunder Bay District, or Cochrane District, or somewhere a little south of there; and taiga or something else? I've only seen a few bird books, but they all depict bird ranges that vary from place to place in such a large area. Nyttend (talk) 02:03, 5 May 2014 (UTC)

Northeastern Ontario. Not the Sudbury chunk. Surrounded by conifers, but a fair bit of field. The bird comes out in the warm season, when dawn starts around 5. Haven't heard him yet this year. That's all the clues I can give. InedibleHulk (talk) 08:10, May 5, 2014 (UTC)

May 4

Immoplex glandular

There's a nutritional supplement called Immoplex Glandular. I can find a lot of sites online that sell it but I can't get anything to tell me exactly what it is. Searching for immoplex here doesn't find anything. So can someone tell me what it is? I'm just looking for what this is. I'm not seeking medical advice. So please don't hat this question. Dismas|^(talk) 01:12, 4 May 2014 (UTC)

Snake oil? According to that article it "has come to refer to any product with questionable or unverifiable quality or benefit." That seems to fit here. HiLo48 (talk) 01:24, 4 May 2014 (UTC)

Could you give me a reference for your guess? Dismas|^(talk) 01:35, 4 May 2014 (UTC)

That you question, and are unable to verify, it's quality or benefit, would seem to indicate it is of "questionable or unverifiable quality or benefit". StuRat (talk) 01:47, 4 May 2014 (UTC)

Oh, FFS! I just asked what it is. HiLo suggested that it's snake oil and I asked for a reference for that, thinking that it might also tell me what immoplex glandular is. Now you want to pick nits over snake oil claims. Just can someone tell me what it is? Dismas|^(talk) 02:19, 4 May 2014 (UTC)

What is it? "A mixture of glandulars, including adrenal, pancreas, thymus and spleen tissue. Our natural glandular material is derived from government-inspected, range-fed animals, raised in New Zealand and Australia, whose animal husbandry regulations are among the strictest in the world. The material is lyophilized, which means it is immediately frozen, then subjected to a high vacuum that vaporizes moisture directly from the solid state". [25] AndyTheGrump (talk) 02:23, 4 May 2014 (UTC)

So, various glands that are chopped up and freeze-dried. Thank you! I've never seen glandular used as a noun like that before. Dismas|^(talk) 03:51, 4 May 2014 (UTC)

Hmmm, As someone from that presumably exotic sounding but safe source of food, Australia, I'd like to know more about those "government-inspected, range-fed animals". HiLo48 (talk) 02:28, 4 May 2014 (UTC)

"Lyophilized" just means it's freeze-dried.

So, how would those organ meats affect you ? I suppose if you managed to eat them in sufficient quantity they might give you gout. StuRat (talk) 02:31, 4 May 2014 (UTC)

Yes, why is it? Snake oil reasons? InedibleHulk (talk) 02:34, May 4, 2014 (UTC)

StuRat explained that above at 01:47, 4 May 2014 (UTC). HiLo48 (talk) 02:42, 4 May 2014 (UTC)

Yes, but as your fellow Australian has made clear on another desk today, StuRat's answers are of questionable or unverifiable quality or benefit without sources. Not sure who to believe, anymore! Enough to drive a man to drink goat pineal. InedibleHulk (talk) 04:09, May 4, 2014 (UTC)

I simply repeated and applied the definition of snake oil, and HiLo had already provided the link to verify that. As for the quality of my responses, judge for yourself, as taking somebody else's word for it is simply accepting an argument from authority, which is a logical fallacy. StuRat (talk) 04:18, 4 May 2014 (UTC)

That's what I meant by "not sure who to believe". Jack didn't cite jack in jacking your credibility. So maybe he didn't. You do seem to make good points, after all. InedibleHulk (talk) 04:27, May 4, 2014 (UTC)

Yes, Stu was effectively quoting an earlier post of mine, and I've never knowingly touched goat pineal. I do know that there are thousands of feral goats in western New South Wales currently being rounded up and sold on the export market. We don't want them. You can have them. As for those government inspectors, with the kinds of budget cuts our government is currently threatening us with, they will probably be a very rare breed themselves soon. HiLo48 (talk) 04:21, 4 May 2014 (UTC)

No thanks, I have 17 allegedly domestic goats I need to round up everyday already. Stupid alleged barriers. And yeah, the quote was more effective than I may have let on. Good work, Stu! InedibleHulk (talk) 04:27, May 4, 2014 (UTC)

Despite some colorful worries, goat pineal should contain some active compounds. :) Wnt (talk) 05:21, 4 May 2014 (UTC)

Though the living gland doesn't shoot its magic into the stomach first. That seems like it could complicate things. I think I'll just leave them in the goats, where they seem to be working fine. InedibleHulk (talk) 17:12, May 4, 2014 (UTC)

Well, melatonin comes in pill bottles, and I doubt there's much magic involved there. Wnt (talk) 05:21, 5 May 2014 (UTC)

Exactly. Compared to granting a goat lucid dreams, its medicinal properties are pretty bland. InedibleHulk (talk) 08:18, May 5, 2014 (UTC)

To go back to the OP, it is reasonably common in Western allopathic medicine to treat glandular deficiencies with mammalian glands or their extracts. For example, hypothyroidism was first treated by George Redmayne Murray in 1891 by feeding patients sheep thyroid, while beef or porcine insulin are still used to treat Type I diabetes (in the UK at least). So maybe not snake oil, then. --TammyMoet (talk) 09:01, 4 May 2014 (UTC)

Thank you, Tammy! That was very helpful! Dismas|^(talk) 14:01, 4 May 2014 (UTC)

Note the key word "deficiencies". If a person is indeed deficient in some nutrient, then nutritional supplements could help. However, most people aren't deficient, and therefore more of those nutrients wont help. (And if people eating a western diet are deficient in a nutrient, it's likely to be something we should be getting from vegetables, not meats.) StuRat (talk) 16:10, 4 May 2014 (UTC)

What's the difference between Supernova 1a and a Nova?

They sound like almost the same thing. ScienceApe (talk) 05:50, 4 May 2014 (UTC)

A nova is when a white dwarf flares up and then goes back to the way it was -- a supernova destroys the star. 24.5.122.13 (talk) 06:40, 4 May 2014 (UTC)

• A nova can occur with a star of any size over a certain limit toward the end of its life. An S1a occurs when two stars in close orbit interact, with a white dwarf, near the nova threshold, siphons gas from its larger main sequence or red giant neighbor. Since the white dwarf is just under the set limit for a nova, it will explode justa as it meets that mass limit from accreted gas, meaning the S1a's will always explode with the same energy and brightness, allowing us to tell their distance by their relative brightness. μηδείς (talk)

May been it different in a moving orbits?--Alex Sazonov (talk) 09:15, 4 May 2014 (UTC)

The main difference is that a Nova is a temporary flare of hydrogen fusion on the surface of a white dwarf, while a Type Ia supernova occurs if, due to the accumulation of extra mass on the surface, the core reaches critical conditions and explodes due to large-scale carbon (and oxygen) fusion. --Stephan Schulz (talk) 11:15, 4 May 2014 (UTC)

So then wouldn't it stand to reason that a Type Ia supernova should undergo nova before it goes supernova in the case of a white dwarf? ScienceApe (talk) 14:38, 4 May 2014 (UTC)

Not if the mass accretion is fast enough and/or the white dwarf was already close to the Chandra limit to begin with. 24.5.122.13 (talk) 02:29, 5 May 2014 (UTC)

What is it been a electromagnetic induction?

Is it been a electromagnetic induction is beening a natural life of the World?--Alex Sazonov (talk) 09:51, 4 May 2014 (UTC)

I don't understand what you mean by "a natural life of the World", but does the Russian article Электромагнитная индукция or the English article Electromagnetic induction help? Red Act (talk) 10:21, 4 May 2014 (UTC)

Thank you! I been mean, that a electromagnetic induction always been safe a life of the Nature of the World because a electromagnetic induction always been a elementary structure of all natural life of the World.--Alex Sazonov (talk) 10:47, 4 May 2014 (UTC)

Just because it is natural does not mean that it is safe. Natural electric phenomena include lightning, and geomagnetic stormss. These two can cause strong radio waves with electromagnetic induction. The electric eel can use electricity to damage its prey. Graeme Bartlett (talk) 12:33, 4 May 2014 (UTC)

Thanks, ofcourse a electromagnetic induction is been not safely. I been want to add, that a biological cells always been grow up and divide after a electromagnetic induction to been done it.--Alex Sazonov (talk) 13:48, 4 May 2014 (UTC)

Electromagnetic induction does not normally affect living cells -- what are you talking about? 24.5.122.13 (talk) 02:23, 5 May 2014 (UTC)

Yes, it is been not safely. A metabolism of a biological cells always been done by a electromagnetic induction.--Alex Sazonov (talk) 04:50, 5 May 2014 (UTC)

In itself a biological cells always been a material of a active inductions protoplasm.--Alex Sazonov (talk) 05:15, 5 May 2014 (UTC)

A biological cells always been haven a electromagnetic potential.--Alex Sazonov (talk) 07:31, 5 May 2014 (UTC)

If you hook wires to a dead frog, yes, it will dance. And if you charge money to see it, yes, people will pay. Maybe not a lot of people. But the electromagnetic revolution is been has potential to shock the world. Capiche? InedibleHulk (talk) 07:54, May 5, 2014 (UTC)

Why been not, if a biological cells always been haven a elementary electric charge, in according that a biological cells always been haven a electromagnetic potential, it is been done always really.--Alex Sazonov (talk) 10:34, 5 May 2014 (UTC)

A electric always been done a diffusion of all biological cells!--Alex Sazonov (talk) 14:53, 5 May 2014 (UTC)

May been a electromagnetic potential of a biological cells could been program a biological cells for growing up.--Alex Sazonov (talk) 12:17, 5 May 2014 (UTC)

Is it been in a science that a biological factor been a technical factor?--Alex Sazonov (talk) 12:25, 5 May 2014 (UTC)

Scientific publishing/communication and language

Is sharing of science not hindered by articles being published in a variety of languages? Won't work be slower because some don't realise that work has already been done and published in, say, French? --129.215.47.59 (talk) 15:50, 4 May 2014 (UTC)

The vast majority of scientific journals are in English. Even journals that used to be non-English like Annalen der Physik are now English-only. Mr.Z-man 16:04, 4 May 2014 (UTC)

Major scientific studies are sure to be translated into all the major languages. However, obscure studies may not be, and that could, indeed, result in duplication of effort. StuRat (talk) 16:05, 4 May 2014 (UTC)

In my employment as a reseach and development engineer, 95% of journal articles I've needed to consult were in journals published in English speaking countries. Until the recent advancement of China, the bulk of original research has originated in the USA, with small amounts comming from Canada, Britain, and Europe. Some important fundamental stuff (in combustion chemistry, & physical constants for properties of materials, at least) was done in the Soviet Union, but they made a point in publishing high quality English translations, as trying to prove that Communism was great was an aim. The other 5% I've had to consult, not available in English, was written in French or German. These are not difficult languages to translate, particularly, for me, German. Since it often takes a few hours for me to understand fully a typical article, and extra hour or so to translate it myself is not significant. Japanese is a very difficult language, but not a lot of original research happens in Japan, and they like to publish in American journals anyway. China is fast rising in the volume published in English language journals. I don't know if they publish much exclusively in Chinese language journals.

I imagine the experience of others is similar. What I hate is old articles using non-SI units - conversion is frought with error.

StuRat has no idea what he is talking about. Perusal of almost any professional journal with show that just about any article has a comprehensive list of references included. Where original research was published in a non-English language, you will invariably find the non English papers listed. Pure research is often deliberately duplicated in various universities, in order to improve understanding and guard against error in experimental technique or conclusions (And, we must admit, sometimes because somebody just doesn't believe what he's read). So, the chances of a professional researcher being unaware of work done elsewhere is not at all great regardless of language(exceptions are sometimes said to occur where work has been classified for military defence reasons, e.e., nuclear munition design, but that is rare and pretty much pointless for most stuff).

The first thing you learn in university as an undergrad science or engineering student, right after you learn to give the professor what he wants (they all have their foibles and pecularities), when doing a project, is do or have done a good literature search. It's cheaper that way. Universities and companies involved in pure resarch and applied research have librarians skilled in hunting stuff down for you. If your company is too small to justify in-house libarians, you can hire a university or outside literature search organisation. That costs money, but you soon learn it's cheaper than doing the literature search yourself.

1.122.161.156 (talk) 16:48, 4 May 2014 (UTC)

Much of it makes sense, but where do you get the "Until the recent advancement of China, the bulk of original research has originated in the USA"? The US is a major science contributor, to be sure, and has always been on the forefront of commercialising results, but in both number of publications and impact, Western Europe and the US have been about equal. The rise of English as the lingua franca of science (and the world) has more to do with the fact that English language scientists formed the largest single block, and that most educated people in first-world countries learn English as a second language, anyways. I personally like English, and there is a large advantage in making research accessible to the largest number of people. But there are also people who support some weak version of the Sapir–Whorf hypothesis, and think there is a risk that we lose certain ways of attacking a problem by communicating (and increasingly thinking) in just one language. I have some sympathy for that, too. German authors write differently than English language authors, and that brings a different perspective that can be valuable. For a related experience, just compare the same article in different language editions of Wikipedia. --Stephan Schulz (talk) 18:29, 4 May 2014 (UTC)

See The World's Best Countries in Science - Scorecard, Scientific American, page 36 & 37, October 2012. This measured the effectiveness of applied research by tabling research papers, patents issued, and the number of science and engineering doctorate degrees issued. It makes it very clear that at that time, the output of the USA far outpaced all other countries. Patents, which are a very rough indicator of applied research / R&D output, were ranked as follows, all data scaled to make the USA score 100 points: USA 100, Germany 20.4, China 19.8, Japan 18.4, France 11.7, Canada 8.3. Other European countries, and my own country, Australia, had insignificant output. I recall that Scientific American had another look at it by comparing countries by the number of journal articles cited in other articles, which again showed the USA far outweighing other countries, with China fast catching up. What is sad is that the output from the Russian Federation is just about neglible, far below the output of even small countries with poor science & math education, like Australia. Russian output under the Soviet system was quite substantually greater. My own experience in R&D is that almost every new or important has arisen in the USA. The popular press in various countries can erroneously make it look different. For example, British publications tend to claim that the British invented computers. They made some contributions and went down some blind alleys, but the architecture of computers as we know them originated in the USA and Germany. Australian press likes to claim that Australia invented the instrument landing system. We did not. Some chap proposed that an ILS system be devised, but that is akin to me anouncing we should build low cost vehicle to go to mars. Musing means nothing.

I totally agree with you that thinking in another language, and working in a different culture too, can bring new & different insights. It's one of the reasons why some of the old Soviet research has turned out important. One has only to compare the the American psychiatric manual DSTM, used throughout the English speaking world to guide diagnosis and research, to publications from non-English speaking countries - one would think they must have people from another planet to work with. Perhaps we are the little green men. 1.122.97.123 (talk) 01:43, 5 May 2014 (UTC)

I don't know about patents (which, of course are an indicator of the commercial aspect), but for papers, Thomson Reuters seem to indicate otherwise. The US is the single biggest contributor, but Germany, Britain, France, Italy, the Netherlands, Spain and Switzerland combined already beat it. If you go outside Western Europe, the combination of Japan, Canada, China, Australia, South Korea, India and Russia also is roughly on par. In my field, the US was a very strong pioneer, but in the last 15 years has yielded much of the field to Europe. --Stephan Schulz (talk) 05:40, 5 May 2014 (UTC)

English wasn't always so strongly the primary language for publishing papers. In the late 1960s when I completed a Science Degree at the University of Melbourne I had to satisfy the requirements of a "Science Language" study to get a degree. If I remember correctly, the choices at the time were German, Russian and French. Having studied French at high school I was allowed to sit a test which involved translating a couple of shortish texts with the help of a French-English dictionary. Others had to do a one-semester course. Some time between then and now that requirement was dropped. HiLo48 (talk) 00:53, 5 May 2014 (UTC)

RNAses in tissue culture

Do animal cells in culture produce RNAses that might impair lipofection with mRNA? I'm thinking that with mRNA you're better of electroporating or else using plasmid. --129.215.47.59 (talk) 15:56, 4 May 2014 (UTC)

Help identifying a bee/wasp

Today I have found a group of bees (or wasps, I'm not sure) nesting in the ground under my shed. This is a photograph of one of them (the holes to the right of the picture are the entrance/exit of the nest). Could anybody tell me what they are, and what action I should take? (I'd prefer to leave them in peace, but they are very close to the house and I have inquisitive little children). I'm in England, if that helps. Thanks in advance! — sparklism ^hey! 16:30, 4 May 2014 (UTC)

Looks like some type of bee, to me. I don't see the narrow waist most wasps have. I even think I see full pollen sacs on it's leg, so it looks like it's been busy gathering food/pollinating flowers. Since you don't have Africanized honey bees there, your kids should be reasonably safe, since a bee does die when it stings, so is reluctant to do so. One danger, however, would be if your kids step on the nest in bare feet. You might want to encourage them to wear shoes and maybe put up a little temporary fence around the nest. StuRat (talk) 16:39, 4 May 2014 (UTC)

I’m sorry, I don’t know, but may been a genome-modify. As for me, I’m always been beware of a geno or a genome modifications. Please, be carefully of it.--Alex Sazonov (talk) 17:21, 4 May 2014 (UTC)

• Yes, given the location and the nice heavy pollen load, it's a standard european honey bee. So long as your kids are old enough to understand the danger and mature enough not to yield to temptation, and you don't have vulnerable pets I'd let them bee. Seeing if you can get an epi-pen and warning those who enter your yard (or their guardians) would be a good idea. You might call whatever they call town halls where you live and see if there are any requirements you seek their removal. μηδείς (talk) 17:51, 4 May 2014 (UTC)

I been read a something in which been said, that all insects always are been a modify genome because it they always are been much in a birthley.--Alex Sazonov (talk) 18:11, 4 May 2014 (UTC)

• I don't think it's apis melifera, as Medeis suggests. For one thing, A. melifera don't dig holes in the ground, they nest in pre-existing cavities, e.g. in trees. See Beehive, which says "Western honey bees show several nest-site preferences: the height above ground is usually between 1 metre (3.3 ft) and 5 metres" This site [26] from the FAO also agrees: "A. mellifera [nest in] caves, rock cavities and hollow trees"

A key question: are there several holes in the ground? If so, I suggest that it is an aggregation of solitary bees. Some Halictidae are quasi-social, and share one main entrance hole, with each female laying her own eggs in her own "apartments". I agree that they can probably be safely ignored, as long as they a shown a little respect they will likely not be aggressive. SemanticMantis (talk) 20:34, 4 May 2014 (UTC)

One concern would be if any of your kids are allergic to beestings. I think there's an allergy test for that, so you might consider having that done. StuRat (talk)

I think that you will find these are Mining bees see: [27]. Richerman (talk) 21:05, 4 May 2014 (UTC)

Sparklism made no indication that the bees were excavating a nest in the soil, he said on the ground, under a shed. Given he said bees I assumed there was some quantity, not solitary nest diggers. μηδείς (talk) 00:58, 5 May 2014 (UTC)

The picture surely seems to suggest a nest completely consistent with mining bees, between the entrances and the soil composition, and there's no indication that the shed itself is being used as support for the den in the the photo itself. As has been pointed out above, some species of solitary bee are known to be quasi-social and to build nests with communal entrances. I have no knowledge of how common the behaviour is in Andrenidae, but, without having a much higher resolution image, I'm going to say Andrena looks to be rather our suspect based on purely external physical taxonomy. Snow talk 01:56, 5 May 2014 (UTC)

The photo shows clear excavation, to me. To clarify, so-called "solitary" bees often aggregate in large numbers, in the dozens to hundreds at least, and thousands are not uncommon. This page [28] claims that "The largest recorded aggregation is 423,000 female bees in an area of 1300 m2". "Solitary" here refers to the social structure and division of labor and reproduction, it doesn't mean they nest in isolation from conspecifics. I didn't realize that "solitary bee" was a redirect to "bee"; that's unfortunate. The main point is A. Mellifera doesn't dig, so the photo sort of rules them out. The Andrenidae that are suggested below are indeed solitary, and look to the casual observer much like a common honey bee. I now put my vote in for Adrenidae spp. SemanticMantis (talk) 02:09, 5 May 2014 (UTC)

Yes, I'll concede the point given the holes at the top right f the picture. I was only looking at the be herself. μηδείς (talk) 17:36, 5 May 2014 (UTC)

Rich has the right of it on this one, I dare say. Location, hive structure and, most tellingly, morphology, all match.. I would add to this discussion only that we should be careful about being too laissez-faire about the danger implicit in their location in the OP's yard. Most species of Andrena may be no more aggressive than most bees of this size if not provoked, but then children are known to provoke. I usually preach efforts at co-existence with most all the little buggers out there, who fascinate me no end, and in this day and age in particular, it is a shame to kill or disrupt any industrious pollinators, but the OP must do what is wisest for their family, which may include calling a "pest" expert. Though there can be little doubt what their recommendation will be. Snow talk 00:14, 5 May 2014 (UTC)

• Some great responses guys - thanks! I now think they are Mining bees; Richerman's link is very useful. There are indeed several holes where earth has definitely been excavated: I counted eight holes, all roughly in a line across about a metre of ground. Not sure what I'm going to do about them yet - I really want to leave them alone, but they are very close to my house (which is a shame - we have such a huge garden) and I don't want my little ones getting stung. — sparklism ^hey! 06:16, 5 May 2014 (UTC)

your local wildlife trust, or an organization such as The Bumble Conservation Trust may be able to help you with both identification and appropriate action. DuncanHill (talk) 17:45, 5 May 2014 (UTC)

Science memes

For you interest: the paper on "science memes" has been getting some traction in news and social media today. I've made a list of the "memes" listed in the article that do not currently have articles here; User:Impsswoon/Science memes. -- Impsswoon (talk) 16:55, 4 May 2014 (UTC)

Yes, that sounds like a good list of articles most if not all of which probably ought to be created. However, the science reference desk probably isn't the best place to bring that list to the attention of the editors of science articles, since the reference desk is really just for answering reference questions. Since those missing articles appear to all be in the fields of physics and chemistry, I think probably the best two places to bring this to the attention of appropriate sets of editors would be Wikipedia talk:WikiProject Physics and Wikipedia talk:WikiProject Chemistry. Red Act (talk) 20:07, 4 May 2014 (UTC)

Articles only exist if people like you and I write them. So if you have any knowledge on these subjects, just start writing. Before your article get to more than a paragraph or two, you should start thinking about finding references for the things you're saying - but if these are truly "memes" then that shouldn't be a problem. But Red Act is also correct - you can always request an article at the appropriate WikiProject...although, since those are all volunteer efforts too - there is no guarantee. SteveBaker (talk) 01:56, 5 May 2014 (UTC)

Using WP:Requested articles would be another avenue to consider. Red Act (talk) 15:55, 5 May 2014 (UTC)

Tamest, most docile pet?

Is there a way to determine which is the most docile pet (traditional ones, e.g. dogs, cats, horses, excluding exotic ones), loving kids, and less likely to harm anyone?--Carnby (talk) 20:58, 4 May 2014 (UTC)

A pet rock shouldn't bite. More on the living side, a painted turtle is pretty mellow. InedibleHulk (talk) 21:04, May 4, 2014 (UTC)

Yes. First, how do they react when they see you ? Do they growl and hiss, run and hide, or come up to be petted ? Then you can have somebody make a loud noise in the room and see how they react to that. And, if you have other pets in the household, or may want to, watch how they react to other animals, too. And when they pass all the other tests, have them meet your kids. (I leave that for last, in case your kids fall in love with them, only to find out they are unsuitable.)

A pet which has been raised with kids is more likely to be tolerant of them. However, if your kids are too small to know the basics, like "don't pull it's tail", then maybe stick with a fish, until they get older.

Personally, for safety, I choose pets that can't hurt me much, even if they want to, like cats. Having a pet that can kill you if it gets angry seems seriously unwise to me. My brother had a great dane, that turned on him and got his jaw around my brother's head, putting teeth marks on both side. His skull almost cracked. That dog was put down after that.

And remember there are other important aspects to a good pet, like if they are house-trained, if they are high energy pets needing constant play, or if they are old and/or sedentary, and if they have any medical conditions. StuRat (talk) 21:05, 4 May 2014 (UTC)

Are you interested only in land animals? Goldfish would probably count as a traditional pet, but it's less likely than anything else you mention to do anything to you at all. Nyttend (talk) 01:55, 5 May 2014 (UTC)

A sheep probably - they don't bite. Not great pets though. Maybe a Budgie - they do bite, but while it hurts it can't do any damage. Ariel. (talk) 02:19, 5 May 2014 (UTC)

Sheep do bite. Had four as a kid, and two often bit me. And headbutted me, while making scary sounds. The other two, never. It's nothing to worry about, compared to scraping a knee, but maybe not good for a fragile child. InedibleHulk (talk) 02:24, May 5, 2014 (UTC)

How about a pet lamb? They're docile and, subsequently, delicious. RomanSpa (talk) 05:42, 6 May 2014 (UTC)

The animal that has been domesticated longest is the dog. No other species can match its history of interaction with humans. Although they vary from breed to breed, they are generally more biddable and friendly to humans than any other species, and have better skills at reading human emotions than other species. So long as you select an appropriate breed you are unlikely to find a gentler or friendlier animal. RomanSpa (talk) 15:25, 5 May 2014 (UTC)

Summary: inform yourself beforehand about the specific breed, pick the right breed, pick a pet with a personality that you like, pick it young, educate him to shape his behaviour. Nowadays there are lots of information on Internet, just spend a few evenings browsing. You even have specialized TV shows. The local book shop will happily sell you a dozen books on the topic. The key is informing yourself before buying anything and getting stuck with the wrong type of pet.

Small dogs will be a lot safer than big ones. Getting bitten by a smallish dog is inconvenient and can leave scars, but it should never be life-threatening. Schnauzer dogs are very loyal and should be kid-safe, and they come in small size. Husky dogs are medium-sized, but they are very coward, they should be quite docile and kid-safe. Always check the characteristics of a breed before choosing a dog. Be wary of which experts you listen to, some people will insist that all dogs are kid-safe, other experts might not warn about all the negative characteristics. Some breeds are much safer than other. Some breeds show high tolerance for rough games with kids. Of course, every dog will have its own personality, but picking a "kid-safe" breed is an important first step.

Check Guinea_pig#Pets, they are coward and really safe, be sure to pick a short-haired one for hygiene. Hamsters can be made docile, but they have this tendency to confuse you finger with food, and they have other inconvenience.

Cats are very docile if you pick them at very young age, feed them by hand, and make sure to play with them a lot of time every day when they are young. Idem for dogs. In general, if you pick them young, and your kid plays with them since a very young age, they will get used to almost anything. (I remember a kid who dragged his cat by the tail through the street; the cat protested in loud voice but never scratched him.) Be sure to reward him for behaviour you want to encourage, and scold him for behaviour you don't want him to display. Make the rewarding and scolding as soon as the behaviour appears for the first time. Buy guides on educating cats and follow them! By personal experience, I know that this applies to cats, dogs, budgies and guinea pigs. Don't know about other pets.

For all animals, always insist on examining several exemplars before choosing, together if possible. Pick them as young as possible. Look at their behaviours and how do they react when you approach your hand. Each one will have its own personality! Do you want a playful one? Do you really want the one that won't stop moving all the time? Do you prefer one that will try to sleep all day? To pick the most docile one, look for the ones that are less active than the others, won't resist being touched, and won't resist being handled. Don't pick the first animal you are offered, unless you know the person and they can guarantee that it has the type of personality that you are looking for.

Adult dogs give problems if they change owners, other pets might not have this problem.

Of course, this will be useless if you can't educate your pet to behave. Watch Dog Whisperer with Cesar Millan for educating dogs correctly. Buy a guide for your type of pet. For dogs/cats/horses, try to get breed-specific advice.

There are lots of information in the internets about types of pets, breeds, etc. People in specialized discussion forums might help you or tell you about specialized resources. --Enric Naval (talk) 07:32, 6 May 2014 (UTC)

Labradors, Golden retrievers and many other medium or large breeds are child friendly. However common sense (and experience) suggests that you choose a dog only if your family dynamic is right - very small children will need supervision. And I would disagree with Enric both on small dogs, and very strongly on Huskies as a family pet. All the best: Rich Farmbrough, 07:44, 6 May 2014 (UTC).

Do people kill more often in their families or outside?

Hi there,

My wife is an avid novel reader. In the novels she reads it is emphasized that people kill more often inside their families. She therefore asked me for a psychological explanation of the phenomenon. The question caught me off guard. I've never thought of this and I am not sure if this assertion is correct to begin with.

What do you think?

Thanks, --AboutFace 22 (talk) 23:02, 4 May 2014 (UTC)

It's "common knowledge" that "Most victims are murdered by someone they know", but I don't think that takes into account all the unsolved ones. Most murders (at least in the US) are unsolved, largely because there wasn't an obvious suspect. It's common enough for the husband to be arrested for someone else's murder, simply because it's "common knowledge" that husbands murder wives and swear they didn't.

So the numbers are a bit skewed, whichever answer you get.

For the third time in recent days, a recent Cracked article partially backs me up. InedibleHulk (talk) 23:10, May 4, 2014 (UTC)

Might be something in victimology for you. InedibleHulk (talk) 23:13, May 4, 2014 (UTC)

As for the psychology behind why many people are murdered by family, there are stronger emotions shared by close people than by strangers. All the seven deadly sins go into overdrive during affairs, divorces, regular spats about dishes. And people let their guard down around those who already live in the house, without witnesses, so it's a very conducive situation. InedibleHulk (talk) 23:19, May 4, 2014 (UTC)

It might not be so much psychological as a geographic/temporal phenomenon. Statistically, if if an individual shoots someone, that is not a member of s/his family, it usually means s/he has taken their gun out of their home and gone round to commit a premeditate homicide. This takes time, during which, the gun holder can reconsider s/his motives. As every football player knows, s/he is no longer playing on home ground in this scenario. However, in the family home, an argument can start and before brain-has-been-able-to-engage-finger, the fatal shot has been fired.--Aspro (talk) 23:29, 4 May 2014 (UTC)

"For the first time, statistics show you are more likely to be murdered by a stranger than somebody you know. My advice, then, is to introduce yourself to everyone you meet." - Saturday Night Live. StuRat (talk) 00:21, 5 May 2014 (UTC)

Aye, the setting differences change the killers' psyches. All part of the same package, not an "or" thing. Space drives the getaway car, time offers a safehouse, but it's always some lousy brain pulling the trigger. InedibleHulk (talk) 00:55, May 5, 2014 (UTC)

I recently watched a TV show featuring a forensic psychologist (or similar law enforcement professional), who made the observation that when a criminal preys on someone they know, it's basically an indication of a lack of criminal sophistication. Like picking an easy target because they happen to be handy and convenient. Minus a powerful emotional trigger like jealousy or revenge, this could be the reason a murderer or other criminal might target a relative or acquaintance. Geographic profiling shows that criminals are also more likely to target victims geographically close to them.OttawaAC (talk) 01:15, 5 May 2014 (UTC)

I think some responders here have been a little quick to validate this old chestnut without bothering to support, or contextualize, that position with approrpiate sourcing/validation. Point in fact, the OP is quite right to question whether or not this rule of thumb is correct. For one thing, there is the confounding factor that many forms of killing which can be unambiguously labelled murder nonetheless fall into conceptual categories that we aren't necessarily thinking of, first and foremost when we consider murder in the context of violent crime (be it a crime of passion or a consequence of other criminal activities). Is a man killed in a race riot the victim of murder? I dare say so. How about one killed in a terrorist attack? I'm sure most of us would say yes. There are many other such examples, though admittedly, not all of them are as common in the developed western world as elsewhere, and the OP may have been intending the question to be considered narrowly within the context of such nations and of crimes of passion vs. conventional violent crime for profit, excluding ethnic, political, and militant contexts as well as accidental (but faultable) killings. However, even within these narrower contexts, there is still considerable question as to whether a person is more likely to be killed by someone they know. There are many vagueries at work, including but not at all limited to 1) the unknown facts in a great many murders 2) the fact that statistics are held and analyzed by disparate agencies and researchers with different standards and perspectives and 3) the inherent subjectivity of some assesments -- a man goes to a meth dealer, who he's run into on the street before, but something goes wrong and the buyer ends up dead -- did he "know" his killer? Specific statistics have been bandied about purporting that a person is more likely to be shot in the United States by someone they know, but of course not all shootings are fatal, nor are all fatal shootings murder.

Getting to the heart of OP's question about the psychology at work, there are a number of different factors at play. Several have already pointed to the fact that many murders are crimes of passion and that both premeditated and spontaneous killings of this sort are likely to involve a person they have strong feelings for. What these arguments don't take into account is that a situation can involve a person (or circumstances) which cause violent impulses associated with a person the attacker is close to, without that person being the target of the violence (as with a jealous lover or a revenge killing) and it's hard, without statistical evidence or research of some sort to take it for granted that these are less common than the familial individual becoming the target. There is also a substantial and well-recognized aspect of the psychology of violence which works counter to close family members becoming victims. Specifically, many experts in the cognitive, psychological, and social sciences have noted that it is easier to commit violence against another when the victim can be conceived of as fundamentally different and of another category of person from the attacker, or not at a person at all -- that is to say, when they are The Other. There is a complex hierarchy of "otherness" that has been observed across cultures where violence is considered increasingly unacceptable when directed against (in reverse order) those of the same regional or cultural identity, those of the local community, the broad kin group, the extended family, immediate family, and, generally least acceptable of all, offspring -- though there is evidence that in the contemporary world, where we increasingly interact with people from far away and from drastically different cultures, our circles of inclusion for "us" (as opposed to "them") are getting broader, contributing to a general decrease in violence where people are reduced to "not-quite-human" or at least not quite the same and thus valid candidates for violence that would not be applied to someone more similar. But it is generally agreed by a great number of experts that there is an innate, genetic, propensity to avoid violence against kin. So if we are in fact today a tendency for more murders to be committed by someone who shares a familial association with the victim, then it is arguably because murder is generally less socially acceptable today, and carries greater risks associated with the immediate community than it often did in the past (and certainly in the prehistorical context in which the majority of the evolution of our psychology took place), but that some still cross that line under certain emotional circumstances personal relationships can engender and it is thus that the historical trend has been flipped (if it in fact it has).

There's a lot of good material out there for the psychology of murder, but much of it focuses some subset of killing or another. I think in looking at this particular question, a broader approach might serve. There's an excellent book written by cognitive scientist Steven Pinker titled The Better Angels of Our Nature in which he presents the case that we are currently living in a period of time that is, statistically and to an extent culturally, the least violent in all of human history (and presumably prehistory as well) and that a general decline in violence has been under way for a long time, much as we impressionistically often feel things are only getting worse; he looks at killing and other forms of violence in a wide swath of contexts and across the historical record, examining the psychological elements that drive violence and those which restrain it and trying to determine what has led to this slow decline. If I may suggest, you and your wife might find it a fascinating read. Snow talk 01:31, 5 May 2014 (UTC)

It is my wont to always thank people who post answers/comments to my questions, this time is no exception. My wife will read them all tomorrow. I've already shown her the volume of the knowledge she will have to digest. Personally I like StuRat's humorous quotation most. Many thanks. --AboutFace 22 (talk) 02:12, 5 May 2014 (UTC)

May 5

Aviation rumble

In an aviation context, what is "rumble"? The pilot of Northwest Orient Airlines Flight 710 reported rumble soon before ground impact, but there's no link. I didn't think Rumble (noise) was very likely (why would you report hearing white noise?), but nothing else at rumble was relevant. The ground was snow-covered at the time, so rumbling thunder wouldn't be as likely. Nyttend (talk) 02:06, 5 May 2014 (UTC)

The crash was due to flutter, which is often manifested as a rumbling or buzzing noise coming from the wings or tail. 24.5.122.13 (talk) 02:14, 5 May 2014 (UTC)

I don't know why it said on the Rumble page that a rumble is white noise - White noise is a hiss, whereas a rumble is low frequency noise. I've now changed it. Richerman (talk) 09:14, 6 May 2014 (UTC)

Concentrated Sun-blackbody equilibrium temperature

If I had a device that was perfectly insulated and lost heat only via blackbody radiation and I put it in the sun and let it reach equilibrium, what temperature would it reach? My intuition tells me it would reach the same temperature as the surface of the sun, but I'm not sure.

What if I used a solar concentrator that doubled the sun (in terms of Solar flux)? I think the temperature of the device would not change (it would simply reach equilibrium faster), but I'm not certain. Ariel. (talk) 02:13, 5 May 2014 (UTC)

The more sunlight the hotter it would get. However, it would never reach the temperature of the Sun because only a portion of it is pointed at the Sun, and the rest radiates heat off into space without getting any sunlight (on the far side) or as much sunlight (on the Sun side, but not pointed right at the Sun). Note that your description is pretty close to an asteroid. StuRat (talk) 02:35, 5 May 2014 (UTC)

I didn't consider the back side of it. For this thought experiment can we just assume it can't radiate from the back? Would angle really make a difference? That's basically the solar concentrator part of the question. Ariel. (talk) 03:16, 5 May 2014 (UTC)

No! Do not assume the device radiates in only one direction, because that dangerous road leads you directly into un-physical conclusions! Heat flows from hot to cold: and if you hypothesize a "one-way radiator" then you are forcing heat to flow from cold to hot! That violates the second law of thermodynamics and is, statistically, very improbable! Even if your surface is very reflective, and well insulated from the other parts of the device, heat will still flow and radiate from all sides. Nimur (talk) 14:58, 5 May 2014 (UTC)

Where's the problem Nimur? Talking about thermodynamics is already a violation of the First law of thermodynamics. Or is it? - ¡Ouch! (^{hurt me} / _{more pain}) 09:28, 6 May 2014 (UTC)

Yes, angle makes a big difference. This is why the tropics are so much hotter, because they get sunlight straight on, versus at a shallow angle near the poles, although both are in sunlight about half the time. In fact, right at the poles, in summer, they get 24 hour sunlight, yet it's still cold there, due to the shallow angle. StuRat (talk) 04:28, 5 May 2014 (UTC)

I know that for Earth, but I'm not so sure it applies to my question. The angle changes the flux of sunlight (so it provides more power), but I'm unsure if it changes the temperature of an item that does not get cooled (so power is irrelevant). Ariel. (talk) 05:35, 5 May 2014 (UTC)

Clarification: By "put it in the sun" I assumed you meant "placed it in the sunlight". However, it now occurs to me you might have meant "placed it inside the Sun". Which is it ? StuRat (talk) 02:39, 5 May 2014 (UTC)

I meant in sunlight :) On Earth, if it matters. Ariel. (talk) 03:16, 5 May 2014 (UTC)

The Sun is the same brightness per unit area no matter how far away it is. So if you set up a cunning shell of mirrors (not even with lenses, though the net assembly is a lens or something like one) that shoots sunlight at an object from 180 degrees, then you could make it so that an object is lit up the same as if it were in very low orbit around the sun, and if you insulate the back, it should be the same temperature. Wnt (talk) 04:32, 5 May 2014 (UTC)

Now, to continue your thought experiment, to get a temperature equal to that of the Sun, you would need the object to be surrounded by Suns on all sides, so that no space was visible (distance to the Suns wouldn't matter). Note that I didn't say the temperature of "the surface of the Sun", since many of the photons emitted from the Sun come from below the surface, where it's much hotter. The corona is also hotter, but it doesn't emit much light, at least not in the visible range. So, the Sun really can't be modeled as if it were a solid sphere of constant temperature. StuRat (talk) 04:40, 5 May 2014 (UTC)

(Replying to both of you) This is kinda what I suspected, but I was trying to confirm that the intensity (distance, angle, or concentrator) of the sunlight has no affect on the equilibrium temperature of the object. So basically while photons from the sun don't have enough power (in the scientific meaning) to burn something (in the ordinary light on earth), their temperature is actually quite high. I assume there has to be an "equivalent effective temperature" for the Sun, including all the layers - I don't suppose you know what it is? Ariel. (talk) 05:35, 5 May 2014 (UTC)

Color temperature#The Sun discusses the effective temperature of the Sun. StuRat (talk) 13:56, 5 May 2014 (UTC)

The effective temperature of photons that come from the Sun will be smaller. To see this intuitively, consider operating a reversible heat engine that takes in heat from the Sun, converts part of to work and dumps waste heat in the Earth's environment. In the limit of maximum efficiency, the heat engine will be reversible. Suppose that we attempt to realize such a heat engine by bringing photons from the Sun to the Earth and using these photons to extract the work. If we can do that with the same maximum efficiency, the photons will have the same temperature as that of the Sun.

Imagine putting a box in the Sun and filling that with photons. When you extract that box, the volume that the box occupied will be filled with the photons in the Sun and that process is irrevesible. You could have extracted the box in a slow versible way by letting the photons perform work as they fill in the gap left by the box. That work that you are not extracting is not available when use only the photons from the Sun, therefore the maximum efficiency will be less than given by ther Carnot formula.

So, what is lost is the work done by radiation pressure. To see this more formally, consider a box filled with photons at temperature T. The internal energy is proportional to T^4, so we can write E = a T^4. Then according to the fundamental thermodynamic identity we have dE = T dS - P dV. If we keep the volume of the box constant, we have dS = dE/T = 4 a T^2 dT. Integrating gives S = 4/3 a T^3 = 4/3 E/T.

When you use an amount of energy E from photons from the Sun, the entropy thus decreases by E/(3/4 T_sun) which has to be balanced by waste heat that is dumped into the environment. This means that the effective temperature is 3/4 T_sun, the difference between this and T_sun can be traced back to the radiation pressure of 1/3 E/V which is not available in practice to perform work. You could argue that you do have an entropy of E/T if you capture phtons emitted by the Sun on Earth, when keeping the momenta of the photons which point away from the Sun. It is only when you fully thermalize the photons that the entropy jumps to 4/3 E/T. In the former case you can extract the work done by radiation pressure, in the latter case you can't. Count Iblis (talk) 14:39, 5 May 2014 (UTC)

This question can be answered using a standard equation: Planetary equilibrium temperature. That equation is derived from the Stefan–Boltzmann law for radiated power, using a method similar to what Count Iblis outlined above; it accounts for geometry and radiant efficiency (albedo).

This type of question - the temperature of an object floating in space - is often asked as a homework question in introductory classes on astronomy and planetary science. In an advanced class, you might also incorporate terms related to the blackbody temperature of the cosmic background (which is not absolute zero); so the efficiency of radiation is lower than ideal; but this only makes a very tiny change to the result. Nimur (talk) 14:42, 5 May 2014 (UTC)

Vacuum tube filament conditions

I must have made a mistake somewhere, but I can't see where.

I obtained some 1S5 directly heated vacumm tubes. According to RCA publications, the filament in these is a simple high purity tungsten wire (presumably round) with a microscopically thin coating of alkaline earth oxides. The construction of this vacuum tube is such that the filament can be seen (just, as it's diameter is tiny) at the ends, about 10% of the way in from the ends, and about 25% in from one end. Upon energisation of the filament only with the rated filament voltage (1.5 V), in a darkened room you can just see it glowing a dull red. This means its' temperature is then about 700 K, and loss of heat by conduction into the supports must be negligible (as otherwise it would not glow near the ends), and virtually all heat is lost by radiation.

I measured the filament cold resistance (300 K, ie a room temperature of 27 C) carefully with a digital multimeter, compensating for lead resistance. It was 9.75 ohms. I measured the current drawn at 1.50 V - it was 52.23 mA, indicating a hot resistance of 28.73 ohms. Using Worthing's formula, R = ρ_1K.T^Pw, where ρ_1K, = 5.97 x 10^-7, Pw = 1.205, I calculated that the filament resistivity at 300 K is 5.77x10^-8 ohm.meters. The filament length by inspection is 25 mm. I then calculated the filament cross-section area (1.48x10^-10 m²), its' diameter (0.014 mm), and its surface area (1.078x10^-6 m2).

Using Worthing's formula again, from the hot resistance, I calculated the temperature as 736 K, close enough to that estimated by visual inspection.

From RCA and textbooks, emissivity of oxide coated filaments is about 0.3. But due to radiation being proportion to the 4th power of temperature, the emissivity value doesn't matter much.

Using the formula (stefan boltzman law), P = A σ ε (T⁴ - T_A⁴), where P is the electrical power disipation, A is surface area, σ is the Stefan-Bolzman constant, 5.67x10^-8 W/m²K⁴, I found interatively the temperature at which, with the surface area it has, the electrical power equals the thermal radiated energy. It worked out as 1204 K (should be 736 K), at which I = 28.05 mA (should be 52.2 mA), and P = 42.0 mW.

Where have I gone wrong? Have I overlooked something? Why is the temperature rise by Stefan-Boltzman about twice what it should be?

Strictly speaking, I should have inserted the anode temperature as it intercepts the filament radiation, and not assumed radiation to ambient. But allowing for anode temperature rise would make the error worse. I left the anode and grids open circuit. So there is no net electron flow, so there is no evaporative cooling of the filament. 144.138.223.88 (talk) 04:42, 5 May 2014 (UTC)

Hmmm, I'm thinking the power emission should be 1.5 V x 52.23 mA ~= 75 mW. Your calculation of the surface area 1.078x10^-6 m2 looks right, but I don't know your figures for this filament really are right. Dividing I get 70,000 W/m2 of emitted power (some of which is IR). Dividing this by σ ≈ 5.67 × 10−8 W/(m2K4) yields 12345 x 10E13 K⁴ and taking the square root of this twice yields 1054. So I didn't find a flaw on the first run-through myself. Still, even a small error in the estimation of the filament diameter could explain it all. Wnt (talk) 05:40, 5 May 2014 (UTC)

Yes, the electrical power in, which should equal power emitted, is 78.3 mW. I notice you did not allow for the ambient temperature. As the ambient is 300 K, it will radiate back to the filament, so the net emission is a little less than 78.3 mW. But, no, a small error in diameter doesn't change the picture, as the surface area changes in proportion. Increasing the diameter by 10% changes the filament temperature by only 6 K. You need to increase the filament diameter, or its length, by almost a factor of 10x to get rid of the error. 121.221.131.231 (talk) 10:30, 5 May 2014 (UTC)

Our table for incandescence doesn't even go down below about 820 K. Are you sure the very low 700K figure accurately represents the cold temperature of the filament, and you're not just seeing that it's small and dim? Wnt (talk) 12:55, 5 May 2014 (UTC)

You mean the hot temperature. Obviously, the 700 K figure was a rough one. I could only just see a faint red line in a darkened room. The light sensitivity of eyes varies from person to person in any case. My wife can detect an oven's hotplate glow several seconds before I can. The Wikipedia article on thermal radiation has a table Subjective color to the eye of a black body radiator lists 750 K as "a faint red glow." but does not indicate the data is for a darkened room. The point, is the visble effect, the measured current, and the manufacturer's design description for the tube type all point to a temperature 700 to 750 K or so. Yet my calculation based on the Stefan-Boltzman law indicates 1200 K and also indicates the filament should draw only about half the current that it does. Why? What have I done wrong or forgotten? 121.221.131.231 (talk) 14:19, 5 May 2014 (UTC)

Math check: from your 0.014 mm I get 1.10×10⁻⁶ m², and then from 21 mW and the Stefan–Boltzmann law, I get 762 K with $\epsilon =1$ and 1029 K with 0.3. --Tardis (talk) 13:06, 5 May 2014 (UTC)

That's with $T_{\text{A}}=0$, which is a good approximation here (even $(300/762)^{4}\approx 2.4\%$). --Tardis (talk) 13:13, 5 May 2014 (UTC)

It's not as simple as that. If emissivity is increased from 0.3 to 1, the consequent lower temperature will decrease the electrical resistance and more current will flow, counteracting the drop in temperature. It's a non-linear system - you cannot simply calculate directly, you must iterate. Calculate the temperature with Stefan-Boltzman law from a gusetimate power input, calculate the new resistance with Worthing's formula for that temperature, from that calculate the power dissipation and then use s-b law again to find the new temperature. Do it all again until you settle on a temperature. For emissivity = 1, I get 979 K (which would glow bright red) and 37.02 mA, so power dissipation has increased to 55.5 mW. That's still a 30% error in current and a 56% error in temperature rise. That degree of error definitely needs explaining. Incidentally, I mistyped the 21 mW figure. It should be 42 mW (1.5 V x 28 mA). 121.221.131.231 (talk) 14:37, 5 May 2014 (UTC)

Vegetable wash and pesticide residue in produce

Is vegetable wash of any kind effective in reducing pesticide residue in produce? (To be effective the amount of pesticide residue remove has to make a significant difference in terms of health risks.) Any data?

Would Vodka (as a food-grade aqueous ethanol solution), applied as a spray before rinsing with water, be effective in removing pesticide from produce?

Thanks. — Preceding unsigned comment added by 173.49.15.150 (talk) 12:05, 5 May 2014 (UTC)

Here are the results of one study. Here is another one. Here is yet another. Here are some general guidelines for cleaning fruits and vegetables. Here is a synopsis of another study. --Jayron32 12:46, 5 May 2014 (UTC)

As an aside, Vodka is always recommended, but usually liberally applied to the cook, rather than the vegetables. --Jayron32 12:48, 5 May 2014 (UTC)

Perhaps after any cooking appliances have been used and turned off. Definitely not before... [29] [30] [31] [32] Nil Einne (talk) 13:19, 5 May 2014 (UTC)

It is a proven fact that alcohol dramatically improves the quality of food. When my family was running a small hotel, we told Cook to stop ordering such high amounts of sherry, about a litre per day, and we monitored the kitchen orders to ensure he complied. Straightaway the food quality deteriorated, so we sacked him, and hired a new cook who we thought had mastered the difficult art of cooking high quality meals without alchohol. But new cook used quite a quantity of sherry too. Beer as well. 121.221.131.231 (talk) 14:54, 5 May 2014 (UTC)

Scientific names

In Bregmotypta Bruce, 1994E - what does the "E" represent? All the best: Rich Farmbrough, 16:51, 5 May 2014 (UTC).

There are probably five sources in the paper from 1994, or one authored by an author identified by the initial E. Without a link to he source it's hard to tell. μηδείς (talk) 17:27, 5 May 2014 (UTC)

Another option is that, in the work where this appeared, four other papers written by Bruce in 1994 had previous been cited. For example "According to Bruce (1994a)..." , and later "This species has three toes (Bruce, 1994b)", etc. The letter labels of the papers written by the same author(s) in the same year are not part of the bibliographic record though. For example, a paper cited as "Bruce, 1994b" by Jones (2000) may be cited as "Bruce, 1994a" by Xu (2001). As Medeis says, if you tell us where you found this quotation, we could probably answer more confidently. SemanticMantis (talk) 19:17, 5 May 2014 (UTC)

• There's an example of this usage here. DuncanHill (talk) 19:21, 5 May 2014 (UTC)

Thanks! Here's that database's bibliography [33]. Sure enough, there are six papers cited there, all by Bruce, N.L., all written in 1994. Since the bibliography doesn't give letter codes, we might assume that it was chronologically the fifth paper published that year. The paper that is the authority for that species is this one [34] (which is listed second at the prior link.) Bibliography and taxonomic authority are tough, and standards don't always exist, and aren't always followed... For example, this species also has (a different) Bruce 1994 as the authority [35] in the same database, but no letter is given, and the full title of the paper is present. One final thought: in botanical naming conventions, there are a few single-letter codes with well-accepted meanings, e.g. 'L.' for Linnaeus. But according to our article, the International_Code_of_Zoological_Nomenclature doesn't seem to use single letters in that way. Perhaps a move towards a PhyloCode would help resolve some of the ambiguitiy. (And despite the link, I remain unconfident as to the true meaning, if any. It could always be an error, the result of poor quality control and quality assurance in the database. I hope someone else might know for sure! ) SemanticMantis (talk) 02:22, 6 May 2014 (UTC)

Yes, I read most of the ICZN's articles on naming, and there was no explanation. I couldn't see how the rather paper-oriented Harvard citation style could pollute the naming conventions, but I guess if someone tries to combine the naming and the cites (they should write Bregmotypta Bruce, 1994 [Bruce 1994E]) then this could happen. I propose to remove the "E" at Sphaeromatidae, and anywehre else I find it. All the best: Rich Farmbrough, 07:50, 6 May 2014 (UTC).

[In this edit respected user Stemonitis removed most of the post-annual letters, so I think we are on safe ground. All the best: Rich Farmbrough, 08:25, 6 May 2014 (UTC).

Medium-Chain Triglycerides preservation

What is the best way to storage products that contain them (such as Coconut oil) for best preservation of these Medium-chain triglycerides? Cooling? Darkness? (If yes, why --- is it only because of oxidation concerns?), thanks. Ben-Natan (talk) 20:05, 5 May 2014 (UTC)

Most sites I found here note a shelf-life for unrefined coconut oil to be about 2 years, and none of them recommend any special procedures (such as refrigeration) beyond what you would use for any other cooking oil. --Jayron32 23:52, 5 May 2014 (UTC)

More, this site: here, in the search above, recommends storage either in the refrigerator or the pantry; so darkness appears to extend the shelf-life, but not cold, per se. The problem is that it has a very high melting point, meaning that coconut oil stored in the fridge can get hard, and need to be thawed at room temperature before use. --Jayron32 23:55, 5 May 2014 (UTC)

Generally the cooler foodstuffs are, the slower any degrading reaction, and most biological decay processes are. Coldness only becomes an issue when it damages the foodstuff (as in strawberries), or when the cold storage is done incorrectly allowing degradation, for example by sublimation. All the best: Rich Farmbrough, 07:57, 6 May 2014 (UTC).

May 6

is anything harder than diamonds? if not, why not?

our article Superhard_material says: "Diamond is the hardest known material to date with a Vickers hardness in the range..."

why? Shouldn't we have discovered or synthesized something harder - after all, diamonds have been known about for millennia? Is there any particular reason that with all the advances in chemistry, millions of newly synthesized and discovered compounds, elements, and materials, we still don't have anything harder? Is it hte hardest hting that COULD exist - and if so, why? 212.96.61.236 (talk) 02:41, 6 May 2014 (UTC)

The Carbon article makes the smaller claim that diamond is the hardest naturally occurring substance...which leaves open the possibility of artificial substances that are harder.

If I had to speculate as to why diamond is so hard, it's because carbon atoms really love to bond together in large groups - and because the 'face-centered-cubic' crystal structure is an incredibly closely packed crystal. I don't believe any other elements bond together as well as carbon does - and I don't think there is a way to pack atoms more tightly than in face-centered-cubic. So it wouldn't surprise me if diamond couldn't (even theoretically) be beaten for hardness.

But I think we're going to have to wait for a chemistry expert to come along to answer this question...I'm only guessing here.

SteveBaker (talk) 03:11, 6 May 2014 (UTC)

One thing to understand is that there are some materials for which the hardness cannot realistically be measured. To measure the hardness you need a sample with macroscopic size in all 3 dimensions. So the hardness of things like carbon nanotubes, graphene, and linear acetylenic carbon can't be measured. But they have tensile strengths comparable to or better than diamond, which suggests that they would have comparable or better hardness, if it could physically be measured. Mr.Z-man 03:33, 6 May 2014 (UTC)

Reading further the articles also says:

"The hardness of synthetic diamond (70–150 GPa) is very dependent on the relative purity of the crystal itself. The more perfect the crystal structure, the harder the diamond becomes. It has recently been reported that HPHT single crystals and nanocrystalline diamond aggregates (aggregated diamond nanorods) can be harder than natural diamond."

One might also consider the hardness of Neutronium.

But as to original question, I would guess that diamond is very low energy state mechanically, and thus when it occurs very stable. Such ultra stable things hang around for many millions for Man to find.

As to graphene and nanotubes/rods as they are 1 and 2 dimensional I would net expect them to be hard, but rather to flex and distort under compressive load. One might imagine, though, protecting a diamond cutter with a layer of graphene... All the best: Rich Farmbrough, 08:07, 6 May 2014 (UTC).

(Massive WP:OR ahead!)

I'd say the octet rule pretty much proves that carbon is optimal; the maximum of electrons in the outer shell is eight, so the maximum of bonds any atom can have with equal atoms is four. There might be exceptions, but they would be unlikely to beat the total strength of the bonds.

The corresponding elements are found in the 4th period of the periodic table: carbon silicon etc. (The article mentions that there are many exceptions over 20, so we don't need to go past silicon.) These elements have four electrons each, so these are "half a bond" each, ready to bond with neighboring atoms.

Only materials with a regular mesh look promising; if different bonds are at different length, they will probably be somewhat above their ground state and thus easier to break. This would not only rule out amorphous materials but also most if not all compounds of more than two different elements. Two-element compounds could be competitive, if all bonds are between different elements.

Carbon or silicon is easy to decide; with carbon, you have more bonds per kg; so even if they are slightly weaker than those of silicon, they represent a higher "total bond strength." OTOH, the "bonds per kg" is probably the wrong metric when it does not come to specific strength; a "bonds per m²" metric would be more useful. Carbon is the winner in both, but the margin is much smaller in the latter. - ¡Ouch! (^{hurt me} / _{more pain}) 09:47, 6 May 2014 (UTC)

Superconductor question

I have several question about superconductor:

1. If we have a superconducting power line powering a load at 100 kV, will it arc to another conductor or the electricity will prefer to go to the easy way instead of arcing everywhere?

2. Do anyone have invented the superconducting switch yet?

3. Is superconducting electrical stuff is more compact than normal conducting electrical stuff? 118.137.229.230 (talk) 10:13, 6 May 2014 (UTC)