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July 4

Is the CMB a baby picture of only the observable universe?

Is the Cosmic Microwave Background a "baby picture" of the entire universe or just the observable universe? If the observable universe is all we're able to see then isn't the CMB picture incomplete? Or can we extrapolate from the CMB how the entire universe appears beyond just what is observable? 184.65.230.52 (talk) 01:59, 4 July 2015 (UTC)

The observable universe. Dragons flight (talk) 02:17, 4 July 2015 (UTC)

The CMB light that's just now reaching us has all traveled about the same distance, so its points of origin form a sphere centered on us. That sphere is the boundary of the observable universe. CMB maps like the one to the right are Mollweide projections of the sphere. So not only does the map not directly tell us about the universe outside the boundary, it also doesn't directly tell us about the universe inside the boundary. It does contain information about the interior because the light interacted with matter in the interior on its way to us, and it contains information about the exterior because the state of the plasma that emitted the light (about 380,000 years ABB) depended on the earlier state of the universe in all directions, including the directions that are farther from us than the source of the light. -- BenRG (talk) 03:25, 4 July 2015 (UTC)

The source of the microwave background is in the observable universe because we're observing it. That said, the concept of the observable universe is full of tricks. The distance back to the Big Bang in years/light years is real, but the later part of it is measured at a time when the universe is very small. Changes in the rate of expansion affect what is observable - to give a simple example, if the expansion slows down enough, then eventually everything becomes observable, even though it isn't now. On the other hand in a Big Rip eventually nothing is observable to anything else anymore. Wnt (talk) 03:32, 4 July 2015 (UTC)

Hmmm, on second thought, I suppose that a trace of extremely redshifted radiation always exists (the sky before the Big Rip), much like the popularized image that things fallen into a black hole always remain technically visible. The light of the distant stars that has reached within a proton's radius of a nucleus never totally falls away (though a photon almost certainly will not arrive, you would never know it won't, I think) Which makes me wonder now... no matter what cosmic inflation occurred, if the universe was ever entirely observable to itself, I suppose it always remains so, technically? Wnt (talk) 00:57, 6 July 2015 (UTC)

How interchangeable are injection molding molds?

Plastic injection molding company usually follow the following protocol: give us your design and X dollars and we will design the mold and produce Y parts within Z weeks, at the end of which we will send you the mold. My question is, how interchangeable is the said mold? If I take the mold to a different company will they be able to use it? Will the mold produced for one brand of injection molding machine work with a different brand? Are there industry standards for mold sizes and interfaces, and if so, do they differ across different countries? I'm chiefly interested in making ABS parts. My other car is a cadr (talk) 04:00, 4 July 2015 (UTC)

For example, Toshiba America publishes a catalog for Injection Molding Machines that specifies clamp and platen dimensions. You can compare to other manufacturers, and check with each vendor to determine what equipment they use, and whether they permit you to supply your own mold.

Nimur (talk) 13:20, 4 July 2015 (UTC)

Biology: What bird is this? (mp3)

I have heard this Mystery Bird in the media a few times, from the Dark Castle computer game to this recording, taken from the film The Last of Sheila. I thought maybe Whip-poor-will or Loon, but I can't find a match. Thanks! Reflectionsinglass (talk) 18:00, 4 July 2015 (UTC)

It's an owl hooting. The first bit is caught mid-call, but my guess is that it is a barred owl. Our description of the vocalization is accurate and you can hear the last few syllables fairly clearly at the beginning of the file. Matt Deres (talk) 21:36, 4 July 2015 (UTC)

I'm afraid I have to disagree, that's definitely not the call. This call is used in multiple media forms and I've heard it since the 90s and it's never sounded like an edited version of a bird call. I appreciate the suggestion though. I went to the Cornithology site and listened to all the samples and it's not the Barred owl. However, it may very well be an owl of some kind! I'll keep my ears out. Reflectionsinglass (talk) 19:01, 5 July 2015 (UTC)

The "oooooo-d-d-d-d-d" call is most commonly a barred owl. They make many calls, this one being a mating call. When I was young, I'd hear it. Then, the response would be a rising "oo-oo-oo-d-oooooo-d-d-d-d". When I listen to the recording you linked, I don't hear anything that sounds at all different than the barred owls I heard growing up. It just has a bit of echo added to it to make it sound a bit creepy. 209.149.114.69 (talk) 15:00, 6 July 2015 (UTC)

To me, it sounds just like a male Tawny owl response to a broadcast song by the female. I hear this just about nightly where I live.DrChrissy ^(talk) 15:08, 6 July 2015 (UTC)

Just as a follow up, I think that the barred owl and the tawny owl have mutually exclusive distributions. If the location of the recording is known, this could rule out one of the owl candidates.DrChrissy ^(talk) 19:45, 6 July 2015 (UTC)

July 5

Stars

The following is the statement of confusion: In the dense nebulae where stars are produced, much of the hydrogen is in the molecular (H2) form, so these nebulae are called molecular clouds.

Q:

1. Does this mean population I stars are burning H2 and helium in its core? Done
2. Which stars turned H into H2? Done
3. ‘A still gaseous body before any star formation has taken place’ & ‘over-dense region of dark matter in the very early universe’ – Does this mean ‘the foggy universe’ time?

Space Ghost (talk) 21:06, 5 July 2015 (UTC)

H₂ is the normal form of Hydrogen under reasonably cool conditions - e.g. on Earth. In this form, two hydrogen atoms share their electrons in a covalent bond. Under most reasonable conditions, H₂ will form spontaneously. However, the H-H covalent bond is a chemical bond. At the temperature of stars, all chemical bonds break down, and indeed, even the bond between the H nucleus and its electron breaks down. Matter in a star is, nearly without exception, in the form of a plasma. The nuclear reactions that "burn" Hydrogen affect only the nuclei, not the electron shell, of hydrogen. Main sequence stars generally burn Hydrogen, but there are population I stars that have evolved far enough to burn Helium (but not H₂) and have turned into red giants. --Stephan Schulz (talk) 22:08, 5 July 2015 (UTC)

Thanks -- Space Ghost (talk) 19:18, 6 July 2015 (UTC)

Star formation, Evolution & Mass

1. Does it occur only in a giant molecular cloud? Doesn't it occur in a small/medium molecular cloud? Is it called the cold molecular cloud?
2. Does a star's mass increase and decrease with its age, like 'temperature' and 'luminosity'? If so, how? - is it from accretion during its complete life time? How does the mass work out anyway? Does it depend on the chemical element?

Space Ghost (talk) 21:06, 5 July 2015 (UTC)

2. A stars mass will generally decrease with age. Solar wind gradually bleeds off plasma, and mass. This solar wind is driven by the nuclear fusion of the sun, which releases lots of EM radiation. When two nuclei combine to form a third nucleus, that third nucleus will have a mass of less than the sum of the two original nuclei. The difference in mass will result in photons (electromagnetic radiation, light, IR etc.) being given off. The photons leaving the star will also reduce the mass. The only chance of it increasing in mass is colliding with another star, or swallowing a large planet. Big stars burn faster than small stars, e.g. Betelgeuse is a very good example. Early stars with low metallicity burn slower than later starts. Martin451 23:48, 5 July 2015 (UTC)

Is the reason a star moving through a cloud couldn't pick up mass, that the solar wind would blow the cloud out of the way ? StuRat (talk) 00:49, 6 July 2015 (UTC)

I would think that wouldn't be significant. The amount of mass lost to the solar wind is tiny/insignificant. If the cloud were much denser than the solar wind, the volume of the solar wind pressure would decrease as the solar wind heats it. I'm not sure what density it would take to move that pressure volume boundary to within the star itself. I would tend to think there simply aren't enough conic solutions that result in the collision with the star. How much mass does the earth gain from the solar wind vs. loss from energetic escapes? I think the loss of solar mass to both fusion and solar wind over the entire lifetime of the sun is about 0.1% or so IIRC (before Red Giant phase). The solar wind doesn't appreciably affect the orbits of planets. --DHeyward (talk) 08:45, 6 July 2015 (UTC)

Strange things can happen in binary star systems - see cataclysmic variable star. Gandalf61 (talk) 10:13, 6 July 2015 (UTC)

'Zero age main sequence' (ZAMS)! I forgot, sorry. But I'm still not clear of the issue.

Lets say (for example) when the cloud is fragmenting, its accreting material creating a round object, as its becoming heavy, it went up to 5 solar mass and turned into ZAMS. As it decreases its mass, at what mass does it become a red giant, white dwarf, black dwarf? - (the mass is just an example btw) - I understand that once it fuses all of its hydrogen but at what mass it burns all its hydrogen then goes into helium burning phase?

Mass is not the determining factor, as stars with greatly different masses could all be at the same stage (e.g. Main Sequence G2, like our Sun) at the same time. However they would have started at different times as the mass of a star does greatly influence how fast they progress through the various stages of Stellar Evolution, an article which you should read thoroughly as it should clear up many of your misconceptions and answer most of your questions. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 20:53, 6 July 2015 (UTC)

I read it, it uses the word 'mass' mainly to differentiate the evolution of 'cold molecular cloud' & 'GMC' formations, and does not clarify at what mass it changes its phases after the ZAMS. If I knew, say for example, a protosar goes to main sequence after it becomes 5 solar mass, then it goes to orange after losing 2 solar mass, while it is on 3 solar mass and being orange, it goes to the red phase after losing 1 solar mass resulting in with 2 total solar mass leftover, and so on. - If you know what I mean - I need a rough/original figures in order to understand how much mass it decreases in each phase after ZAMS, for low, medium, massive stars, in order to go to the next phase... -- Space Ghost (talk) 19:07, 7 July 2015 (UTC)

Also, I don't understand about the 'early stars with low metallicity burn slower than later starts', I thought the early 'quasars' (not known of its mass) and 'III' stars burnt faster than expected because they had over 100 mass. No information found on 'II' stars mass even though its visible till today. -- Space Ghost (talk) 19:28, 6 July 2015 (UTC)

Two stars of the same mass, the one with low metallicity will burn slower than the one with higher metallicity. The Sun is expected to have a life of 10 billion years. Stars like SM0313 are already 13 billion years old, and likely to burn for a long time. Stars with larger masses burn faster, Betelgeuse mentioned above has a mass of 8-20 solar masses, and is currently 8-10 million years old and expected to go nova in the next million years. Its life will be one thousandth of that of the sun. The early quasars were even bigger than Betelgeuse. Martin451 00:42, 7 July 2015 (UTC)

I'm taking your words for it... Thanks -- Space Ghost (talk) 19:08, 7 July 2015 (UTC)

---

Clarification required:

1. I understand that a Star can accrete, what I forgot i.e. up to what age/time? I assume, even up to the black hole time? Am I right?
2. When does it become a neutron star, after a white dwarf or it depends on its mass/accreation? I believe neutron star do not accreate as it spins extremely fast...
3. Is after a 'supernova' where you don't actually see nothing left at all of a star? I mean 'no round ball'?

Space Ghost (talk) 19:20, 6 July 2015 (UTC)

1) A star could continue to accrete material, if it's surrounded by a dense enough cloud that the solar wind can't push it away. I'm not sure of how dense it would have to be, though. Also, if the cloud was rapidly heading towards the star that would change the calculations. At some mass and/or time a nova or supernova would occur, before it got to a black hole.

2) See neutron star. They can accrete material from a binary system twin.

3) Supernova often do leave a core at the center, perhaps a neutron star, perhaps a black hole, depending on mass, etc. See the chart in supernova#Core_collapse. StuRat (talk) 20:16, 6 July 2015 (UTC)

Okay, thanks -- Space Ghost (talk) 19:08, 7 July 2015 (UTC)

July 6

Sleep immobility

Is sleep paralysis the same state when you fall asleep in a potentially unpleasant position (for example, with head pressing against your arm) and later start to feel numbness due to disrupted blood flow, but is unable to move or wake up? I'm healthy, but had at least one such experience in the past, and this is really a nasty thing. Brandmeister^talk 08:51, 6 July 2015 (UTC)

No, these are quite distinct phenomena. Sleep paralysis involves a more or less complete (though typically very brief) loss of volitional motor function for the whole body, usually occurring during either hypnagogia or hypnopompia (the transitions between full wakefullness to sleep and between sleep and wakefulness, respectively). It results from irregular function in the neural pathways which regulate these states of consciousness and restrict volitional movement when we sleep, lest we act upon mental stimuli while we sleep; sleepwalking, accordingly, is in some sense the inverse of this condition in which those circuits do not operate appropriately while asleep, allowing movement. Sleep paralysis is therefore more or less completely the product of the central nervous system. By comparison, a limb "falling asleep" from pressure on a nerve or the surrounding tissue (with the experience being clinically known as obdormition with regard to the numbness, and parathesia with regard to the telltale "pins and needles" sensation) does not usually involve significant impairment of motor function or proprioception and is best defined as a matter of physiological disruption of the relevant area of the peripheral nervous system (though similar numbness in limbs can, in rare instances, result from brain tumors or other CNS dysfunction). We all, of course, have experienced the sleeping limb phenomena every so often. Most people also have a memory of experiencing sleep paralysis once or twice in their life -- these events (or at least the fully conscious variations which one can later recall) are usually highly transient and exceedingly rare, but there is also a chronic version of the condition in which episodes can last longer and occur more frequently. I do agree, it can be an unsettling experience, even when not fully awake. Snow ^{let's rap} 10:20, 6 July 2015 (UTC)

@Snow Rise: I've always read that sleep paralysis affects motor function without mention of the sensory, and certainly people are sensitive to touch when asleep... yet I've had the personal experience during gout attacks of intentionally maintaining sleep paralysis in the lower part of my body for close to an hour (I think) after reaching wakefulness, during which there was no pain. It was only after "breaking" the sleep paralysis that the pain started. I'm still not sure of the explanation for this. Wnt (talk) 13:57, 6 July 2015 (UTC)

I think you're referring to something unrelated, but I can confirm that I've experienced it as well. For example, if I'm suffering from a cold, I may wake up feeling quite well only to suddenly feel worse after I begin moving. Or, as in your example, a painful or itchy appendage seems to quiet down during the night only to come roaring back as soon as I start moving. I'm curious about the mechanism; I've just assumed that it was due to laying still. Matt Deres (talk) 19:39, 6 July 2015 (UTC)

That's interesting indeed. I've not heard of an instance of a person willing themselves to be unable to move before - and indeed, the idea of volitionally maintaining an inability to engage in any physical act seems somewhat counter-intuitive to me. Do you mean that you simply did not move your lower muscles at all and put yourself in a headspace where you were focusing on what the sensation of not being able to is like? What degree of wakefullness do you recall experiencing? I will say that, as a general rule, nocireception is a highly modal phenomena, often significantly influenced by state of mind, level of consciousness, and other psychological and neurological factors. And then too, it's just as Matt says -- there is a local physiological factor in that gout is a form of inflammation, which can be exacerbated by movement (though as you would well know, a lack of movement does not in itself guarantee an absence of pain). Since I assume the "breaking of the sleep paralysis" yous peak of coincided with volitional movement, I would think this can't be discounted as a factor in this instance, though certainly that doesn't altogether discount some peculiar and uncommon biopsychological effect if you felt genuinely paralyzed, but with the episode lasting as long as it did, I would suspect it was not your typical sleep paralysis but, at least at some point, closer to a kind of self-hypnosis. Snow ^{let's rap} 00:03, 7 July 2015 (UTC)

@Snow Rise: Well, it seems like when I'd had a more 'authentic' sleep paralysis feeling in my childhood, that there was a sense of being unable to move, but that with enough effort, a very slight motion could be made that then would dispel the paralysis. The closer to 'awake' I was, the less effort would be required. The extreme end of that is waking up but still feeling like my limbs aren't actually online somehow until a miniscule effort is made to move something. It seemed like my head could, briefly, be moved without dispelling the paralysis in my legs, and perhaps even arms for a few seconds, but I think moving one part tended to make the 'paralysis' end in the others pretty quickly. (My experimental technique is questionable here since I was doing it only during attacks that should have been avoided, while half asleep!) There's an instinct to just stretch and bring everything online immediately, but a gout attack definitely makes a person hesitate to move anything without thinking... which makes it more feasible not to do so. I should add that during wakefulness, not moving my feet for hours on end would do much less to reduce the pain - the difference is between a very slight lessening and its total absence!

I should add that the nature of the 'paralysis' is not simply a limpness of the muscle. I am personally inclined to attribute things like a stiff neck to falling asleep with a muscle still contracting, and then it stays that way until one becomes aware of discomfort. (Which is a much weaker sensation than what is felt after waking!) Since I avoid doing that I haven't had such trouble in a very long time. I recall such oddities as falling asleep with a college textbook held up above me, and waking up when it fell on me something like an hour later because I'd been holding it the full time, with the stiff sensation in my fingers and hand to prove it. I feel like the sleep paralysis instinct is a perhaps vestigial, or perhaps simply untrained version of an instinct that is supposed to let an ape sleep safely in a tree, holding onto the branches, and so this seems to make sense. But all this is just speculation!!! Wnt (talk) 13:07, 7 July 2015 (UTC)

Interrupted blood flow would mean limb death, not just tingling. It is sometime possible to tell which nerve is compressed or trapped by part of the limb is tingling. For example, it is sometimes possible to compress the nerve on the outside of the elbow through flexion. The middle finger, ring finger and pinky will go numb. A different posture compresses the nerve for the index finger and thumb and they will "fall asleep" in that position. A lot of people don't remember which finger and just remember "hand is tingling." The specifics are good for determining carpal tunnel syndrome or what type of sleeping posture fixes it. --DHeyward (talk) 11:28, 6 July 2015 (UTC)

Re: "Interrupted blood flow would mean limb death" ... that would depend on how long and how complete the interruption is. StuRat (talk) 21:04, 6 July 2015 (UTC)

The OP actually said "disrupted", unless it's effectively the same thing. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:23, 6 July 2015 (UTC)

Is it also due to peripheral nervous system's disruption mentioned by Snow that I can't typically awake (or force myself to awake) and correct my numbness-inducing position? I.e., in such state I couldn't do anything about it, being forced to wait until some critical point when it resolves by itself. Brandmeister^talk 22:25, 6 July 2015 (UTC)

The word you need there is "awaken", meaning "to become awake", although "wake up" is more common in casual conversation. Since you repeat the word, I would use both: "...awaken (or force myself to wake up)...". StuRat (talk) 14:55, 7 July 2015 (UTC)

Looking for research study paper on Fibromyalgia

Hello, I had come across an article on Fibromyalgia and wanted to read the study paper that was related. Unfortunately http://guardianlv.com/2013/06/fibromyalgia-mystery-finally-solved/ did not point to where to get the paper on painmed.org and I am having difficulty trying to find it on this site, as it doesn't seem to host a database (pay or otherwise. Dr. Rice is the name of the senior researcher. Is there a place I can find this paper? Thank you. 67.234.207.4 (talk) 19:56, 6 July 2015 (UTC)

The original research article is here [1]. I googled /Frank Rice Fibromyalgia/, first hit was here [2], which appears to be a nicer, slightly more detailed general-audience summary. INTiDYN seems to be a spin-off business the authors are associated with. Since the latter article includes a Digital_object_identifier reference at the end, I just had to pop that in to http://doi.org to get it to resolve to the original research paper, which seems to be freely accessible. If you have questions about the content of the article feel free to come back for clarification. SemanticMantis (talk) 21:31, 6 July 2015 (UTC)

Oh, here's an even better lay person summary by Dr. Rice [3]. To answer a question you didn't ask - painmed.org is the web page for the professional association. All journal publication and distribution is handled through Wiley [4]. (Fortunately someone paid Wiley US$3,000 [5] on behalf of the authors to make that link accessible to you. Even though Wiley did not pay for the research, or the reviewers, or any of the other costs of research, they seem to think it's reasonable to charge that much to put a pdf on a web page... and they are big enough that they can get away with it. /rant) SemanticMantis (talk) 21:42, 6 July 2015 (UTC)

Elephant seals and rape

Is it true that in every instance of elephant seal copulation, it is the case that the male elephant seal rapes the female elephant seal, and the female elephant seal is never receptive to sex? Malamockq (talk) 21:55, 6 July 2015 (UTC)

I'm not seeing any indication of that in Northern elephant seal or Southern elephant seal. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:05, 6 July 2015 (UTC)

Our rape article is crowned with the hatnote "For rape among non-human animals, see Sexual coercion." Elephant seals are mentioned a couple of times in that article. -- ToE 22:20, 6 July 2015 (UTC)

Even so, if that's how they reproduce, then that's how it is. Animals are not subject to human morality laws. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:28, 6 July 2015 (UTC)

From this description of Northern Elephant Seal reproduction:

Males do not court or investigate the perineal area of the female prior to mounting; they seem to be testing the receptivity of the female. They mount from one side without any preliminaries and seemingly attempt to overpower the female. Males use the great bulk and weight of their forequarters, a fore-flipper clasp, and a neck bite to restrain the animal. They mount pregnant females, those giving birth, females soon after birth, and females in estrus. Only the frequency not the form of these mating attempts varies with estrus. A mount may end in copulation; by the mounter being repulsed by an alpha; or simply because the male ceases the attempt.

Females respond to male mounts by active protest or passive acceptance. A female protests by issuing a virtually continuous train of vocal threats and by whipping her hindquarters vigorously from side to side. Because of their relative positions her rear flippers often strike near the males penile opening. She may also flip sand directly at the males head and face, nip his neck, or struggle to get away. Alternatively the female may remain passive throughout the mount or may facilitate by spreading her hind flippers. Females were not observed to court or solicit copulation.

Estrus as well as non-estrus females protest the majority of mounts attempted by males. ... [This is followed by analysis from a study of 1500 mounts, only 7% of which were not protested.]

Early estrus females protest all mounts. As estrus proceeds protesting is reduced. No-protest is the most common response on the last day of estrus. ... [This is followed by further description of mounting behavior.]

Females near the end of estrus rarely protest mounts and readily accept copulation with peripheral males. During the last hour on land females were extremely receptive to all males.

So the answer is, no, it is not true that the female elephant seal is never receptive to sex. -- ToE 23:03, 6 July 2015 (UTC)

Rape is a human behaviour. If female elephant seals wanted to avoid copulation they would have evolved a mechanism to do this and of course, the species would have become extinct. This clearly has not happened. There are many reasons why a female might appear to be unreceptive to a male - one of these is that she is assessing the fitness of the male.DrChrissy ^(talk) 23:06, 6 July 2015 (UTC)

There is some information at Anthropomorphism#In science may be relevant to this discussion for some readers. MarnetteD|Talk 23:26, 6 July 2015 (UTC)

@DrChrissy: Evolution certainly has no concern for what the females 'want'. Wnt (talk) 00:13, 7 July 2015 (UTC)

I'm afraid evolution has everything to do with what the females 'want'. We are talking here about the motivation of animals. Evolution serves to produce the fittest animals. As pointed out below, females are motivated to mate, but they are also motivated the produce the fittest offspring. Therefore, they have evolved behaviours to ensure this. The females are motivated to mate, but choose who they mate with. I think this thread would have been better if a definition of "rape" was given/discussed - not a criticism, just a comment.DrChrissy ^(talk) 11:23, 7 July 2015 (UTC)

@DrChrissy: I think @Wnt: is speaking from the perspective of Ethology - we cannot ever know an animal's desires, we can only know their behavior. I think you might have been speaking from a more teleological perspective, by which we can often use shortcuts like "want" to describe the end results of a set of behaviors or evolutionary processes. There's lots of things that come in to this elephant seal situation that haven't been linked - sexual conflict, sexual selection, and mate choice cover most of the theoretical context by which scientists would address these behaviors. I totally agree that using the word "rape" confuses the issue, though it also provides an opportunity to clarify the issues. An example that the OP might be interested in - bedbugs reproduce exclusively via traumatic insemination. In short, females have no vaginal opening, and males simple spear into female abdomens with a harpoon-like penis, flooding the abdominal cavity with sperm, some of which manages to fertilize eggs. This can even lead to weird situations where homosexual contact can lead to pregnancy - if a male A spears a male B while B is currently spearing a female C, some of A's sperm can impregnate C! Fascinating stuff, and surely the result of evolutionary processes, but not anything to do with want or rape. SemanticMantis (talk) 14:41, 7 July 2015 (UTC)

Good reply, but actually, it's not what I meant. It's more that it doesn't matter what seals (or people) actually want, but only what they do. For example, think of how many companies run their workers ragged with swing shifts and surprise overtime, when they could just as easily plot out a regular schedule. By keeping their workers miserable, off-balance and insecure, they make it harder for them to look for better work or stand up for their rights. It doesn't matter what the workers think - as long as what they do is desirable to their rulers, that's what counts. Wnt (talk) 16:44, 7 July 2015 (UTC)

But that's also the ethological approach - actions/behaviors are what matter the most (and also have the benefit of being objectively observable). But IMO it's also a bit naive to think that selection can't act on motivations/desires/taxis/whatever you want to call it when a bug or mouse (or plant ;) does one thing instead of another. Of course it's the end result that matters the most, but the whatever notion of "want" is also amenable to adaptation and selective influence, if for no other reason than these "wants" influence behavior. Likewise with your business example, eventually wants can matter if they lead to a Strike_action. SemanticMantis (talk) 17:37, 7 July 2015 (UTC)

Actually, I think we need to invoke the Selfish gene principle. We are all just secretions of our genes. Some of our genes have coded for eye colour, our behaviours and yes, some genes have somehow coded for our motivations. What a great and biologically inexpensive way for genes to perpetuate themselves!DrChrissy ^(talk) 17:45, 7 July 2015 (UTC)

It is in the females(cows) interest to mate. That is why they go onto the beach with a bull, I seem to recall they may even choose which bull to mate with, by going to his territory. Whilst the mating season is on, bulls do not leave their beach and territory, surviving on stored energy, water and protein. The cows also have an issue, they want the best quality sperm so that they can conceive, and want it when they need it.

Supposing a bull has two cows on his beach. He mounts the first, who protests because she is not ready. He then mounts the second who is on heat, she gets all of his sperm. A week later the second cow might protest, he moves his attention back to the first, who is now on heat and accepts him. The first cow now gets more sperm, and a higher chance of getting pregnant.

In short, both cows and the bull win by consensual matting. If the bull rapes all cows he will be wasting sperm, and the cows will have less chance of conceiving. Martin451 01:08, 7 July 2015 (UTC)

July 7

Determining size of screw

What size screw is this?[6]My other car is a cadr (talk) 09:20, 7 July 2015 (UTC)

If it could be an American size, then your diameter measurement (threaded part) places it between number 12 and 1/4 inch. Your measurement of thread pitch, 23 threads per inch, is closer to the 24 threads per inch that is used with number 12 than to the 20 threads per inch used with 1/4 inch. See http://gsi.nist.gov/global/docs/vps/csfiles/cs_24-30.pdf Jc3s5h (talk) 09:57, 7 July 2015 (UTC)

Thanks for the help. I google imaged "1/4 inch screw" and this site[7] shows the same screw I got (at least I hope it's the same screw). My other car is a cadr (talk) 12:29, 7 July 2015 (UTC)

Resolved

My experience with cameras made in America, East Germany, and Japan (all of which were intended for the American marketplace) is the screw that holds them to a tripod is 1/4 inch diameter, 20 threads per inch. If you are in the US, Canada, or the UK, visit a hardware store to check (that's an ironmonger in the UK). Jc3s5h (talk) 12:44, 7 July 2015 (UTC)

Weird pin number setup on QRE1113

I'm trying, and failing, to get a Fairchild QRE1113[8] working here. Embarrassingly enough, I can't even seems to get the pins right. Regarding the second page of the datasheet:

1. Is it just me or is the pin one marker drawn in the "wrong" place? Every other component seems to have it in the upper left corner, but this datasheet drew it in the lower left corner. I said "drawn wrong", because the actual component[9] has the pin one marker in the right place.

2. Is it just me or are the pin numbering completely wrong? What I was taught was this: Dual_in-line_package#Orientation_and_lead_numbering, but the pin numbering from the datasheet completely disregarded convention. My other car is a cadr (talk) 15:19, 7 July 2015 (UTC)

I can't make out the pin marking in the actual pic. Do you have any way to make the device a larger portion of the pic ? StuRat (talk) 15:30, 7 July 2015 (UTC)

Sorry, I don't have have a macro-capable camera so this is best I can do. The component's pretty tiny so it's hard to get a good shot. I highlighted the notch here[10]. My other car is a cadr (talk) 15:47, 7 July 2015 (UTC)

Oops, had a brain fart. If you google image "QRE1113" then you'll get lots of high quality images of the actual device, and by the looks of things, the datasheet was correct. The pin one notch is indeed in a non-conventional spot, and that my device is the "wrong" one here. I'm guessing counterfeiting is to blame here. Funny they managed to copy the actual device but failed to get the pin notch right. My other car is a cadr (talk) 15:54, 7 July 2015 (UTC)

How do you know the device is right ? (You can try hooking it up that way, and let us know if it works, so we can close this Q.) StuRat (talk) 15:59, 7 July 2015 (UTC)

I got it working by brute-forcing all the 12 combinations. My other car is a cadr (talk) 16:11, 7 July 2015 (UTC)

Isn't that 24 combos ? 4 possible spots for first pin × 3 remaining spots for 2nd pin × 2 remaining spots for 3rd pin × 1 remaining spot for last pin. StuRat (talk) 16:16, 7 July 2015 (UTC)

I tried to pin down which one was the infra-red LED first, so that's only two pins; I only needed to brute-force the 1st pin and 2nd pin right (4 * 3 remaining spots), then I know the remaining two pins belonged to the phototransistor.

Resolved

Can a venus fly trap ingest human protein?

Is semen from a human male was regularly placed inside the mouths of a venus fly trap, would it be enough to sustain the plant? 182.253.73.219 (talk) 15:28, 7 July 2015 (UTC)

Venus_flytrap#Carnivory references many detailed scientific papers explaining what is digested and how. Semen#Composition_of_human_semen likewise has relevant information and citations. You can figure out the answer if you're willing to work for it and do the reading. You can ask at WP:REX if you have problems accessing the referenced material. Alternatively you might be able to perform some experiments. SemanticMantis (talk) 17:45, 7 July 2015 (UTC)

We're not really here to make people work for it, so I should point out that polyamines are distinctive components of sperm and contain large amounts of nitrogen, so in theory it should be a good source. However -- biology doesn't know theory. For all I know sperm could contain something that poisons the plant. As usual in biology, the only way to know for sure is to do the experiment. Wnt (talk) 10:53, 8 July 2015 (UTC)

Good luck with the Grant Application. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 12:04, 8 July 2015 (UTC)

How long does it take a droplet of water to evaporate?

I've looked at the article on evaporation, and I can't understand it very well. I know that how long it takes water to evaporate depends on lots of things, but I just want a ball-park figure: suppose I've been in the shower, then go through to my bedroom, where it's not so steamy, and warm enough to be comfortable naked, but not unpleasantly hot. Then how long will it take the water droplets on my skin to evaporate, so I don't have to use a towel? Just a rough answer would be great. Thank you. — Preceding unsigned comment added by 62.56.100.166 (talk) 19:28, 7 July 2015 (UTC)

The amount of time will vary enormously with ambient temperature and humidity. A time range of a minute to an hour would be possible in extreme conditions. In your bedroom it might be five minutes. Why not experiment to find out? Dbfirs 20:59, 7 July 2015 (UTC)

We could pick one of the Standard_conditions_for_temperature_and_pressure. SemanticMantis (talk) 21:52, 7 July 2015 (UTC)

The real issue is how quickly the human body can supply heat to the droplets of water. If you get out the shower, go to your bedroom, and sit down, your heart will slow down, you will begin to get cold, and the veins/capillaries etc. will move from further into your skin to retain heat, evaporation will slow down. If you go to your room, and do sit-ups or press-ups you will generate heat, the capillaries will move close to your skin in an effort to cool down, giving heat to the water droplets, which will evaporate keeping your cool.

The recommended daily intake of calories for a man is 2500, or about 100 an hour, this equates to 420kJ per hour or a sustained power usage of 0.116kW. The heat capacity of water is 4.2kJ(kg^-1)(K^-1) the latent heat of vaporisation is 2260 kJ per kg.

To take 1 kg (=1 litre) or water from 40C (body temperature) to 100C, would need 60*4.2kJ=252kJ of energy. To evaporate that water would need 252+2260=2512kJ.

Assuming the body converts all energy into heat to the skin, at is average over 24 hours, then the body could boil 420/2512=0.167 litres an hour.

This makes a lot of assumptions, including boiling the water, ignoring loss of heat from the lungs etc., and the maths will need checking. Martin451 23:14, 7 July 2015 (UTC)

These are really useless answers. "The amount of time will vary enormously with ambient temperature and humidity..." Yes, as I already said, I understand that there are lots of factors involved. "Why not experiment to find out?" Because I just want an answer, and you, "Dbfirs", haven't provided one. And "SemanticMantis" just says "We could pick one of the standard conditions for temperature and pressure", but doesn't actually answer my question. Then "Martin451" goes down the irrelevant track of discussing the energy inputs to the human body, even though we already know body temperature and I've already specified the likely skin temperature on which the water droplets sit (initially normal shower temperature, and later a comfortably warm, dry room). Also, "Martin451", I'm talking about evaporation, not boiling the water, so talking about raising the water temperature to 100 degrees is obviously wrong. Is there anyone here actually capable of answering this question? At least two of the respondents ("Dbfirs" and "SemanticMantis") aren't physicists, and it's a fair bet that neither is "Martin451". This is supposed to be the "Science Reference Desk", but none of you has answered a fairly simple question. Replies have either been useless or irrelevant. Is there a physicist working here who can help, please? Thank you. — Preceding unsigned comment added by 212.225.93.0 (talk) 23:07, 7 July 2015 (UTC)

You're acting like a jerk, so there's no reason anyone should feel motivated to help you. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:17, 8 July 2015 (UTC)

Dear 212.225.93.0 . How did you shift your geographical location so fast. Are you really the OP?--Aspro (talk) 23:23, 7 July 2015 (UTC)

First you have to answer the question 'How long does it take to read a book?' Short Brigade Harvester Boris (talk) 23:28, 7 July 2015 (UTC)

Water has a huge heat capacity and Enthalpy. If you body is wet at 40C, then evaporation will very quickly cool the skin, unless your body supplies more heat to the skin. The key fact, as I said above, is how well your body can supply heat, and keep the body warm. The fact is to evaporate water you need to supply energy to that water, or it will just get cold, and not evaporate. This is not a simple question, there are two many factors involved, the best way of answering is to make approximations, and estimates. The other solution, as mentioned above is to experiment, time yourself, have your bedroom at different temperatures, sit on a chair some days, and do press ups other days. This is the way a lot of physics is done, repeating experiments until you have established all factors involved. Martin451 23:29, 7 July 2015 (UTC)

I haven't shifted geographical location and I'm not sure what the numbers are, and I don't know who "OP" is. What I do know is that none of you is capable of answering my question, probably because you're not physicists. Saying I should do the experiment myself is useless: this is a reference desk, so if you don't know the answer, just don't say anything. However, I've now looked at some of the other questions on the reference desk, and it's pretty obvious what is really going on: the people here are mostly blowhards who get their kicks by pretending to know a lot about lots of different things, but who really don't know much. Lots of the people here try to answer lots of questions that they're obviously not qualified for, and they can't give useful answers. Instead they show off, using long words and making silly jokes to cover for their lack of actual knowledge. If you're not a physicist who can answer the question, please don't reply just to bolster your ego. You should make a list of the physicists, chemists, biologists, mathematicians, historians, economists, linguists (and so on...) who work here, then have a rule that only physicists answer physics questions, only chemists answer chemistry questions, and so on. This would make the reference desk better, and wouldn't leave your users (people like me) irritated. I'm not smart enough to answer my question about evaporation, but I am smart enough to know that it's sufficiently well phrased to describe the problem, and sufficiently clear that a physicist can probably give an approximate answer, which is all that I am asking for. If there's a physicist available here, please would s/he answer me. If you're not a physicist, please don't waste your time and mine. Thank you. — Preceding unsigned comment added by 212.225.93.0 (talk) 23:56, 7 July 2015 (UTC)

If you can waste our time, we can certainly waste yours. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:16, 8 July 2015 (UTC)

Dear 212.225.93.0 . OP means Original Poster that asked the question here. You are posting from London and not from the OP's location. So how did you move from one place to another so quick?--Aspro (talk) 00:03, 8 July 2015 (UTC)

I'm reopening this because although I mostly agree with the closure, there remains an issue important for the wider RD that needs to be clarified.

WTF? I thought we were talking about different countries or something. But in reality for me, the original IP geolocates to Kent, the current IP geolocates to London. The time between posts was over 3h 30 minutes. This was more than enough time to get between the two. After all, some people to commute daily between the 2 [11] [12].

More importantly, geolocation is rarely that precise. London and Kent could easily be the same location simply geolocating differently for whatever reason. Both ranges belong to Demon Internet. Perhaps mostly importantly, there is a good chance there is nothing in between (City of) London and Kent in terms of IP geolocation. In other words, even if the geolocation is precise, you may only have to be in a slightly different place to go from one geolocation to the other. In other words, the OPs responses may be problematic, but the geolocation itself is hardly indicative of anything.

Nil Einne (talk) 03:03, 8 July 2015 (UTC)

Be glad it's within the same country. We get open-proxy users (or more likely just one) who appear from random IP's from all over the world. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:16, 8 July 2015 (UTC)

OK, rough answer = 1 hour. Note that this assumes no wind, which will speed evaporation by blowing the envelope of humid air surrounding your body away. It also assumes no movement during the hour, which would tend to cause drops of water to fall off you. It also assumes you lie down on your back so gravity holds the drops on your chest in place until they evaporate. Now, if you'd like to do that experiment, I'd be interested to see how close my estimate comes. StuRat (talk) 03:44, 8 July 2015 (UTC)

Speaking as a physicist, the question is ill posed. Water wets skin, especially after soap has been used. So the drying may be more like a film of water than a series of discrete droplets. If any droplets do form on the skin, they will have a distribution of sizes and evaporation rates. Hair is hygroscopic and definitely holds lots of water, some of it through capillary action if long enough;hair drying is a completely different physics problem yet still relevant to your comfort. Who knows your skin temperature or what you consider comfortable, or your local humidity, or the length of your hair? How dry is dry enough? What about sweat production? The problem conditions are way too vague to give an honest answer. The physicist in me will tell you to do the experiment. I dry off in less than 10 minutes, even without a towel; my wife's hair can stay wet for hours.

If the question is restricted to what might be a simple, relevant model of evaporative drying, I would probably model you, for the purposes of thermal conductivity, heat capacity, etc., as a bag of water. Then this becomes the problem of water evaporating on an open surface. For this the Penman equation is a reasonable empirical model. If you are instead interested in the physics of droplets, the Mason equation is an approximate expression for the growth and shrinkage of droplets. --Mark viking (talk) 04:04, 8 July 2015 (UTC)

Sorry if my comment duplicates others. The question has far too many variables to answer with any accuracy. The initial water temperature is a factor, briefly, but a droplet on human skin soon achieves a stable temperature slightly below body temperature, unless the ambient air temperature is higher, as in desert conditions or a sauna. In such cases, the temperature will be sightly higher than room temperature. But even more important is the humidity. Evaporation takes place much faster at low humidities than high ones. Wind speed is also a very important factor. Higher speeds facilitate evaporation. Human behavior is also a factor. A high level of evaporative cooling may be perceived as something uncomfortable, and may motivate a person to wipe away or shake off water droplets. Then there are the factors I haven't yet thought about. Reading other answers, they include factors like personal perceptions of what "dry" really means, plus the ever-present hairiness factor. Cullen³²⁸ Let's discuss it 05:37, 8 July 2015 (UTC)

Sedatives

Can you please name three over-the-counter medications which are sedatives or sedative-like in a thick lotion, cream or jelly form. Thanks in advance. 84.13.144.160 (talk) 23:42, 7 July 2015 (UTC)

As far as I know all the OTC sedatives are anti-histamines. So check those. Ariel. (talk) 23:58, 7 July 2015 (UTC)

I would agree with Ariel that OTC sedatives tend to be anti-histamines but the OP mentions “thick lotion, cream or jelly” which are topical medications. IE not a route used for sedation. Can the OP explain more fully the reason behind his question? He may have got the nomenclature mixed up and really be asking something else.--Aspro (talk) 00:20, 8 July 2015 (UTC)

I would like to treat various skin conditions I have. I refuse to go to the doctor because the medicines he prescribes never have the intended effect. Therefore i am currently seeking a topical medication that has morphine-like effects. Fingers crossed. 84.13.144.160 (talk) 06:33, 8 July 2015 (UTC)

One of the rules of the reference desk is that we do not provide medical advice, which is pretty clear precisely what you are after here. If you don't want to go to the doctor, just ask the chemist, they will tell you what OTC topical medication is available. Vespine (talk) 06:58, 8 July 2015 (UTC)

One tip we can give though - the word you're looking for is "painkiller" or "analgesic". A "sedative" is something with a primary purpose of putting you to sleep. Many painkillers are also sedatives, and vice versa, but asking for a "sedative cream" is just strange. Smurrayinchester 08:10, 8 July 2015 (UTC)

July 8

What is the mechanism of vein "burnning"?

I used to hear that the veins are 'burned' (disappear) as a result of using IV antibiotics. Is it right? if it's right, what is the mechanism? 194.114.146.227 (talk) 08:49, 8 July 2015 (UTC)

Bacterial toxicity of Germanium tetrahydride (germaine)

I have found a number of undocumented references to bacterial toxicity of Germanium tetrahydride, the references all are very close to "Germaine is not toxic to mammals but is toxic to some bacteria". What bacteria is germanium tetrahydride toxic to? and in what concentration. What would be a referred reference for this data? Thank YouIronHead83 (talk) 11:09, 8 July 2015 (UTC)