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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)

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)

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)

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)

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 ([4]) 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)

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 [5] 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,... [6]. Anyway, thanks for the link. --YB ^✍ 01:33, 2 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: [7] (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 [8]. 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. [9]. 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: [10]. 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)

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)

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?[11] 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)

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)

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)

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)

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.[12] 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 [13]. 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)

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)

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)

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 [14]. Here's a nice article titled "Simple models of plant learning and memory", that talks about " intelligent responses to complex environmental signals" [15]. 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)

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 [16]. 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 [17]. [18]. 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 [19] [20]. 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)

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)

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)

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)

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?