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July 30

Bone bruise, hairline fracture, or something else?

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

Sorry. APL (talk) 00:08, 30 July 2011 (UTC)[reply]

Just to go on the record here, I very heavily contest the fact that my question has been marked as a request for medical advice. The situation I am inquiring about occurred so long ago that I can't specifically remember when (probably 1-3 years ago), and the question requested information completely separate from advice (I've been around long enough that people should know by now I would be smarter than to ask for medical advice on Wikipedia)...it could have been answered with a simple link or explanation to the differences in symptoms between two conditions. In the interest of not going on an edit war I won't revert the deletion again (WP:BRD, if you will), but I strongly disagree with the question being considered a request for medical advice. Ks0stm ^(T•C•G) 01:11, 30 July 2011 (UTC)[reply]

I'd argue on your behalf, except ... I didn't know how to answer that question anyway. If it were easy to tell what happened by the difference in symptoms, there wouldn't be so many doctors sending people for X-rays. Wnt (talk) 07:05, 30 July 2011 (UTC)[reply]

Cloud phenomenon

Okay, I cave. I've watched several different videos of this phenomenon, so I'm fairly certain it's real, but I have absolutely no idea what's happening here or here. It seems like every time it shows up the person is behind the cloud from the sun, with the sun just below the lip of the top of the cloud, and the cloud has a diffuse, icy pileus around the top. Anyone care to speculate on what's causing these strange light "bouncing" phenomena? -RunningOnBrains^(talk) 00:58, 30 July 2011 (UTC)[reply]

I don't know, but if I had to guess: it looks like a source of bright light sweeps across a cirrus cloud (which may be the anvil of a cumulonimbus cloud). The bright light appears to shift, with different "fronts" of light moving across the cirrus cloud quite quickly. Assuming that the only source of bright light is the sun, and that the atmosphere above the cirrus cloud is pretty boring, the only possibility that I see is that the light is being reflected from below. As it seems pretty sunny out, it doesn't seem like it could be reflecting from a lake with seiches or something - rather, my guess is that it's being reflected at an angle by ice crystals, perhaps in the cirrus cloud, more likely in the cumulonimbus formation just below it. Presumably as the winds shift, or the temperature of the air changes, the light is reflected from a different point or refracted in a different direction, causing the rapidly changing lights.

There's a theorem in astronomy that no body can change brightness in a faster time than it takes light to cross it. I wonder if something similar applies to a situation like this involving the speed of sound. Since the patterns seem to change within 0.5 to 1 seconds, I would picture that the reflecting feature should be less than about 150 to 300 meters in size. But I don't know if that's really valid. Wnt (talk) 06:34, 30 July 2011 (UTC)[reply]

As Wnt suggests,its a form of Sun dog phenomena. The moving clouds are repeatedly occluding a patch of ice crystals in the higher parts. --Aspro (talk) 09:39, 30 July 2011 (UTC)[reply]

Bone tracheas

I was quite confused by the following passage:

One skeleton taken out of this part of the mound had the appearance of a very aged man; the point of the inferior maxillary was almost in two parts, while the trachea was bone all around. Quite a number showed indications of extreme age; seven or eight that I observed had bone tracheas.

The context is a railroad official overseeing the excavation of a Glacial Kame archaeological site in the 1850s. So what's a bone trachea? I put this into Google and didn't find anything useful; most of the results were lists of body parts that happened to have "trachea" immediately following "bone". Nyttend (talk) 01:15, 30 July 2011 (UTC)[reply]

Cartilage tends to turn to bone over time. While some structures normally remain cartilaginous for life, ossification of tracheal cartilage can be a sign of advanced age. Ossification of tracheal cartilage in aged humans μηδείς (talk) 01:35, 30 July 2011 (UTC)[reply]

Try "trachea ossification" on google. Dauto (talk) 01:45, 30 July 2011 (UTC)[reply]

You will come up with the same paper I did above when I googled the same words. μηδείς (talk) 01:52, 30 July 2011 (UTC)[reply]

I always assumed that cartilage in childhood would normally remain cartilage throughout life, aside from issues such as arthritis; thanks for the help. I've now cited the linked PubMed article in a new article here about the site that was being excavated, the Ridgeway Site. Nyttend (talk) 02:33, 30 July 2011 (UTC)[reply]

The history and use of coal balls

The title says it all, pretty much. Does anyone know about the history of coal balls, and what they can be used for? -- $Σ talk contribs$ 01:36, 30 July 2011 (UTC)[reply]

The only reference I can find to anything called "coal balls" at Wikipedia is found at the disambiguation page Niggerhead which indicates they were deposits of Pyrite found in coal mines. I have no idea if this is the item you are looking for. --Jayron32 03:43, 30 July 2011 (UTC)[reply]

I did find another reference to them, at Permineralization they seem to be small carbonate balls that represent the fossilized remains of microscopic plants. --Jayron32 03:51, 30 July 2011 (UTC)[reply]

A third possibility is the black fungus known as Daldinia concentrica. --Jayron32 03:53, 30 July 2011 (UTC)[reply]

I need information about the second possibility, about fossilised remains of plants. Thanks. --

Σ talk contribs

04:03, 30 July 2011 (UTC)[reply]

How about the mixture of clay and coal dust which Marco Polo wrote of and is used as a fuel in China today?—eric 02:59, 31 July 2011 (UTC)[reply]

Clay + coal dust is called a pencil. --Jayron32 04:53, 31 July 2011 (UTC)[reply]

Sounds of Earth from the Voyager Golden Record: volcanoes, earthquake, whale song, tractor... ?

I came across this article: Contents of the Voyager Golden Record, and I found myself trying to recognize the different sounds listed in the "Sounds" section. There is also a list on the NASA website: http://voyager.jpl.nasa.gov/spacecraft/sounds.html You can hear these sounds here: http://www.youtube.com/watch?v=s-6CvmmcG0w

I have several questions:

Does the sound of volcanoes really start at 00:43?
Is it the sound of an earthquake we can hear around 01:05?
The list on the NASA website doesn't mention "Whale song"; but is it that sound that starts at 04:57?
According to the list, there are two sounds of tractor, one that starts at 07:32 and one another at 09:25. The first one doesn't really sound like a tractor to me, rather like a jackhammer. What do you think?
The list mentions "Thunder" before "Mud pots" and "Wind" just thereafter, but I can't hear them. Is it an error? You can hear the sound of the wind at 05:27.

Also, would it be a good idea to rearrange the list and to add the timing, like in the "Greetings" section? Thank you! --Glups (talk) 04:05, 30 July 2011 (UTC)[reply]

The 7:32 tractor sounds like it has Caterpiller treads and no muffler. Edison (talk) 20:01, 30 July 2011 (UTC)[reply]

orbit and mass

Is the mass of a planet related in any way to its orbit? --DeeperQA (talk) 08:17, 30 July 2011 (UTC)[reply]

Absolutely. Please see our article on orbit: "Newton showed that, for a pair of bodies, the orbits' sizes are in inverse proportion to their masses, and that the bodies revolve about their common center of mass. Where one body is much more massive than the other, it is a convenient approximation to take the center of mass as coinciding with the center of the more massive body."--Shantavira|^{feed me} 12:17, 30 July 2011 (UTC)[reply]

How does that conflict with the fact that massive planets - Mars, Jupiter - are in the middle tier of the Solar System, but small planets are on its extremes? — Preceding unsigned comment added by 88.8.79.148 (talk) 13:16, 30 July 2011 (UTC)[reply]

Mars is not particularly massive. Dauto (talk) 14:05, 30 July 2011 (UTC)[reply]

You are right on that. I was thinking about Saturn. 88.8.79.148 (talk) 14:20, 30 July 2011 (UTC)[reply]

No Shantavira, that's completely wrong. Newton has not showed any such relationship which is not observed in practice either. Our specific solar system's history has lead to some patterns described by Csmiller bellow but exoplanets have been found that do not follow that pattern. Dauto (talk) 14:05, 30 July 2011 (UTC)[reply]

Huh? I am quoting our article. Maybe you could fix it if it's wrong.--Shantavira|^{feed me} 15:55, 30 July 2011 (UTC)[reply]

The quotation is correct. Your interpretation of it is wrong. That quotation simply mean that the size of the orbit of the moon around the earth is much bigger than the size of the orbit of the earth around the moon because the earth's mass is much bigger than the moon's mass. It does not mean that if the earth had a second moon, than the size of the orbit of that moon would have to correlate in any way with its mass. Dauto (talk) 18:54, 30 July 2011 (UTC)[reply]

I said nothing about the size of the orbit, just that there is a relation between orbit and mass.--Shantavira|^{feed me} 05:52, 31 July 2011 (UTC)[reply]

The question is clearly about the size of the orbit. what else would it be about? Inclination? right ascension? Dauto (talk) 20:28, 1 August 2011 (UTC)[reply]

See Formation and evolution of the Solar System#Formation of planets. Basically for Mercury to Mars, the Sun is hot enough to boil off most of the hydrogen from the planet. Further out the surface of the planetary core (which would been rocky or metally) would be cold enough for the captured hydrogen (and helium) to be captured - the thermal velocity of the gas is less than the surface escape velocity. In the trans-Neptunian area, there is not much hydrogen to be captured. CS Miller (talk) 13:30, 30 July 2011 (UTC)[reply]

It's not well understood at this time. Count Iblis (talk) 15:00, 30 July 2011 (UTC)[reply]

There are many satellites at altitude 35,786 km above the equator that have exactly 24 hours orbital period, see the article Geostationary orbit. Geostationary orbit is independent of the mass of the satellite. The orbital periods of planets about the Sun are similarly independent of their masses. Wikipedia has a long List of satellites in geosynchronous orbit that have a wide range of different masses. Cuddlyable3 (talk) 00:28, 31 July 2011 (UTC)[reply]

That is only true because the masses of satellites are much smaller than the mass of the earth. The relation between radius, orbital period and mass is Kepler's third law. Unfortunately, the article does not give the general form: M is actually the sum of the masses of the primary (earth) and secondary (satellite). See e.g. the fourth equation in the German article. The geostationary orbit for a more massive satellite is slightly higher than for a less massive satellite. In practice, of course, this mass dependence is buried among parturbations and in all likelihood not measurable.--Wrongfilter (talk) 08:46, 31 July 2011 (UTC)[reply]

Does anyone know what this plant is, please?

A plant grew in my garden, and I've no idea what it is. Or was, as it grew on a long stem and looked temptingly like a cat toy, so my kitten attacked it, and it is no more. Here are a couple of photos: The entire plant: http://www.flickr.com/photos/63456161@N07/5990829659/in/photostream Close up of the head: http://www.flickr.com/photos/63456161@N07/5990829243/in/photostream/ Thanks for any information!Snorgle (talk) 19:23, 30 July 2011 (UTC)[reply]

Allium canadense --Digrpat (talk) 20:11, 30 July 2011 (UTC)[reply]

Thanks - that looks right(although I'm in the UK I suppose it could have been introduced), and it did smell garlicky too. The wiki entry suggests that it's edible AND poisonous, which is confusing, though.Snorgle (talk) 20:26, 30 July 2011 (UTC)[reply]

maybe Allium vineale my 1st guess anyway--Digrpat (talk) 20:33, 30 July 2011 (UTC)[reply]

That looks EXACTLY like it, thanks!Snorgle (talk) 23:24, 30 July 2011 (UTC)[reply]

Funny Science Video Clips

Can anyone suggest funny science clips like the one here Thanks! Barbaricslav (talk) 20:23, 30 July 2011 (UTC)[reply]

Turboencabulator. Cuddlyable3 (talk) 00:02, 31 July 2011 (UTC)[reply]

Unintentionally funny, but hilarious to me. -RunningOnBrains^(talk) 01:03, 31 July 2011 (UTC)[reply]

The "Duck and Cover" routine is probably not as useless as a lot of people seem to think. Obviously if you're within a certain radius of the bomb, you're going to die regardless. The point of "duck and cover" is to save people who are further away from the blast.--Srleffler (talk) 04:39, 31 July 2011 (UTC)[reply]

I think the funny (or perhaps appalling) part is using a cartoon with a turtle and a jingle, instead of a serious discussion of thermonuclear war. I picture a series of these videos, where being raped and murdered is treated to a cartoon and jingle, then maybe having your school bus catch fire as everyone inside slowly burns to death. StuRat (talk) 04:44, 31 July 2011 (UTC) [reply]

I always figured that it was largely to protect you from structural damage - i.e. if the school roof collapses, it's probably a good idea to be under a desk. Sturdy buildings, even near the epicenter of an atomic blast, can survive [1], and may retain enough of their integrity to keep the people inside alive. A book that I recommend reading for those interested in first and second hand accounts of the explosion is John Hersey's Hiroshima. Several of the survivors detailed were within a mile of the bomb blast. Buddy432 (talk) 19:46, 31 July 2011 (UTC) [reply]

A human is a lot sturdier than a building. A steel-framed building will pretty much always collapse when it's subjected to 5 PSI (a miniscule force). A human can survive a lot more than that (5 PSI is roughly equivalent to being punched hard in the gut). Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:51, 31 July 2011 (UTC)[reply]

PSI is not a measure of force, it is a measure of pressure. Assuming your numbers are correct, you should consider what would happen if you were hit with the same force as a punch but over your entire body, just as the building is subjected to the force over it's entire cross-section. If you were standing in the open, you would probably be thrown backwards rather than crushed, but if you were standing against a wall, say, you could easily be crushed against it. How well buildings survive such forces depends a lot of how rigid they are. If they can't move, then they will break. If they can move (by swaying, primarily) then they'll survive in the same way you would if thrown backwards. --Tango (talk) 23:15, 31 July 2011 (UTC)[reply]

Thinking about force and cross section is also part of the logic behind "duck and cover". By curling up into a ball at ground level, even if you aren't under any kind of shelter, you reduce your cross-section to the blast. Better than nothing...--Srleffler (talk) 02:40, 1 August 2011 (UTC)[reply]

How about a bit of Police Squad!? [2] Also, not science-related, I'm afraid - but I was reminded of the late, great Stanley Unwin [3], and more recent Fry and Laurie [4]. Sorry...I'm sure everyone can think of their favourite 'funny clips'... but I couldn't resist mentioning those. Chzz ► 06:46, 1 August 2011 (UTC)[reply]

July 31

Cold fusion

Cold fusion is referred to as "bullshit" above, and the article seems to say as much. I thought that there were reputable scientists, like those at the the San Diego Navy SPAWAR lab, who continue to produce confirmatory results and have never wavered in their support for cold fusion (e.g. [5]) and some Italian outfit that claimed to have built commercial scale reactors in the past year.[6] What is the current status of that controversy? 99.39.4.220 (talk) 00:54, 31 July 2011 (UTC)[reply]

The 'Italian outfit' can be found here: Energy Catalyzer. Opinions on its validity are, shall we say, divided. AndyTheGrump (talk) 00:58, 31 July 2011 (UTC)[reply]

(edit conflict)Certainly not bullshit. Nothing approached with an open mind and a receptive scientific attitude should ever be labeled "bullshit". There is certainly no convincing evidence that it exists (nor known theoretical mechanism by which it COULD exist). But people trying weird science is how some of the greatest advances of mankind have been achieved. Anyone claiming to have "proof" of anything does not deserve your attention. There is only evidence in science, never "proof". And until there is more than occasional irreproduceable evidence of the phenomenon, I say that there is no reason to believe it exists.

That said, the SPAWAR results are intriguing, but I think that we need to think about horses before zebras, in that there is likely some other energy source for the miniscule amount of heat they are able to produce. And I can not find anything about an Italian commercial application, but I can tell you that scam artists have been selling cold fusion kits for years.-RunningOnBrains^(talk) 01:01, 31 July 2011 (UTC)[reply]

It is not bullshit to explore weird stuff in a scientific manner. Cold fusion should be researched as with anything else. It is bullshit to make definitive claims on the success of research when there are none. Let me reiterate: research = good, making up things = bullshit. Much of the problems with the cold fusion was too much bullshit, not enough good. --Jayron32 01:45, 31 July 2011 (UTC)[reply]

What he said ::points at Jayron:: -RunningOnBrains^(talk) 02:27, 31 July 2011 (UTC)[reply]

Strength of atomic bonds

Hello... I was trying to get an idea of the strength of bonds between atoms by imagining that a water molecule, for example, was blown up to a size where I could hold it in my hands and pull it apart. However, I'm not sure how I should scale the force. Should it scale with the cube of the molecule length? Anyway, doing the calculation properly, what would be the force required to pull apart a water molecule if it was, let's say, 10 cm long? What would be the force required to separate two water molecules of that size in liquid water (keeping the individual molecules intact)? (Ignore the question of whether you could actually grasp such a blown-up molecule, and other similar quibbles.) 86.179.2.163 (talk) 01:20, 31 July 2011 (UTC)[reply]

I can't think of a single principle that would allow you to chose the proper scaling factor and in the absence of a principle your question is not answerable. Dauto (talk) 01:45, 31 July 2011 (UTC)[reply]

(edit conflict)Well, unfortunately, I do have a quibble. If you scale the size you still have to figure out how to scale all the other properties, like mass and charge, and this may not be a trivial answer. The H-O bond strength is 460 Joules...note that this is an energy required to break the bond, not a force. This is because at the molecular level the force needed to break a bond is unimportant, it is the energy input needed to break the bond that is constant. For this reason the was that you scale mass and charge becomes important. I feel like someone else should be able to explain this better, but suffice to say it is not as simple an analogy to scale up bond-breaking as it might seem.-RunningOnBrains^(talk) 01:48, 31 July 2011 (UTC)[reply]

460 joules seems vastly too great a number? Did you miss off a factor of ten to the power minus something? Despite the objections, and despite not being able to work it out myself, I feel it ought to be possible to give a sensible answer. To put it another way, if I was shrunk down to the point where I could hold a water molecule in my hand, how hard would it be to pull it apart. It seems like a question that ought to have a sensible answer.... ! 86.179.2.163 (talk) —Preceding undated comment added 01:56, 31 July 2011 (UTC).[reply]

Actually, I was off in two ways. I was trying to say 460 kilojoules (110 kCal), but that's per mole, so take that number and divide by Avogadro's number to get the energy per bond. Sorry. Anyway, it is still a unit of energy, which is the crux of my argument. -RunningOnBrains^(talk) 02:19, 31 July 2011 (UTC)[reply]

OK, well, how would the force generated by my muscles decrease as I shrank? If I could pull 100 kg at full size, and then I was halved in size, could I pull 100/8 kg? 86.179.2.163 (talk) 02:07, 31 July 2011 (UTC)[reply]

Do an experiment. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:37, 31 July 2011 (UTC)[reply]

Silliness aside, your reasoning sounds correct. Various internet sources seem to claim that strength is ~~connected~~ proportional to muscle A) mass, B) volume, or C) cross-sectional area. Not sure which is correct, as no reliable source seems to weigh in on the matter as far as I can tell. -RunningOnBrains^(talk) 02:47, 31 July 2011 (UTC)[reply]

A and B seem pretty much the same, in this case, since the density of muscle is more or less a constant. C would also be the same, if we assume the length of the muscles being compared is the same. StuRat (talk) 18:29, 31 July 2011 (UTC)[reply]

OK, RunningOnBrains gave the OH bond energy, which I understand is the usual way of expressing bond strength, but what I would like to know is the force. For example, what force would be needed to pull a hydrogen atom off a water molecule? More specifically, I guess there would be a varying force as the atom was pulled away, so I would like to know the maximum force at any point during the separation (I'm not sure where that would occur). Does anyone have that information? Or just a ballpark figure that would be representative of a typical molecule would be great... 86.183.129.83 (talk) 21:55, 31 July 2011 (UTC)[reply]

As RunningOnBrains said, it doesn't make much sense to talk about force in this context. It's energy that matters. How that energy is delivered is irrelevant. --Tango (talk) 23:19, 31 July 2011 (UTC)[reply]

I don't understand why it doesn't make sense to talk about force. Could you not use force to pull two bonded atoms apart? Why is that force not (in principle) measurable? 86.183.129.83 (talk) 23:53, 31 July 2011 (UTC)[reply]

Energy is required to do work and work is required to break bonds. Force is important in that you may need a certain minimum amount of force to do work which may require that the minimum amount of force be applied over a minimum amount of time. --DeeperQA (talk) 00:11, 1 August 2011 (UTC)[reply]

I imagine two bonded atoms a bit like like ping-pong balls connected by a spring (albeit a spring that gets weaker at a great distance). If I could physically grasp the two nuclei and pull them apart, would it not require a (distance-dependent) force to do that, just like the ping-pong balls and spring? I do not understand why this force cannot be quantified, if that's what people are saying. Maybe I am fundamentally misunderstanding something. (To be clear, I am not looking for reasons why bond energy might be a more useful quantity, I just want to understand why the force that I am talking about is not, in principle at least, quantifiable, if that's the case). 86.183.129.83 (talk) 00:24, 1 August 2011 (UTC)[reply]

If one can measure molecular potential energy as a function of atomic separation, shown as a schematic here [7], then it is straightforward to measure the minimum required force as a function of the stretch applied. It would be proportional to the slope of that curve. Such curves could be modeled or measured in principle, but there is little practical value to doing so. In the subatomic world nearly all interactions involve transfers of discrete quanta of energy (e.g. quantum mechanics). So it is far more useful to consider the energy involved in various processes rather than than "forces" required, since in practice there is almost never any way to apply a discrete force at the molecular level. Dragons flight (talk) 19:38, 2 August 2011 (UTC)[reply]

Could you not estimate the force by getting a crystal such as an hourglass-shaped piece of ice, calculating the number of water molecules in its smallest cross section, and then measuring how much force was required to pull (not bend or snap) it apart? 2.101.14.124 (talk) 11:08, 1 August 2011 (UTC)[reply]

Here is a table of rupture forces. The atoms in water are held together by covalent bonds, which appear to be on the order of 1000 piconewtons, while the hydrogen bonds between water molecules rupture at a few piconewtons. --Heron (talk) 18:30, 1 August 2011 (UTC)[reply]

Thanks Heron, that is exactly what I wanted. So, let's take a ballpark figure of 10^-9 N. A water molecule is apparently about 3 x 10^-10 m long. If we scale force with the cube of dimension, then the force needed to break a 10 cm water molecule would be 10^-9 * (0.1 / (3 x 10^-10))^3, which is about 4 x 10^16 N. Did I do that calculation correctly? That seems like a silly answer, so maybe the question, and certainly the method, doesn't make sense. 86.176.211.251 (talk) 21:02, 1 August 2011 (UTC)[reply]

Force probably doesn't vary as the cube of the linear scale. What is it as the square of the linear scale? 64.134.228.55 (talk) 00:50, 2 August 2011 (UTC)[reply]

Well, as the square of the linear scale, it would be 10^-9 * (0.1 / (3 x 10^-10))^2, which is about 10^9 N. Going with the square of the linear scale may make some kind of sense. Force = Power x Time / Distance. If I was shrunk down by a linear factor of k, then power would surely scale with k^3? Time is unchanged, and distance scales with k, so overall force should scale with k^2. Still, 10^9 N seems very large. Could anyone check that calculation for silly mistakes? 86.181.202.137 (talk) 11:48, 2 August 2011 (UTC)[reply]

I agree. Here's another way of looking at it. Imagine your molecule is not a molecule but an iron bar. When you scale up the bar, the force required to break it (by pulling) is its tensile strength times its cross-sectional area. Tensile strength is independent of size (in the macroscopic world, anyway), so the force would scale as the area, i.e. the square of the linear dimension. It doesn't surprise me that the tensile strength of a water molecule is huge. After all, it takes a lot of energy to electrolyse water. --Heron (talk) 18:46, 2 August 2011 (UTC)[reply]

And here is some more data: the Young's modulus (stretchiness) of atomic bonds. Compare these to the moduli of more common materials in our Young's modulus article. The upper and lower limits of the YM of a covalent bond, 200 to 1000 GPa, are the same as those of steel and carbon nanotubes respectively. --Heron (talk) 21:10, 2 August 2011 (UTC)[reply]

I think your iron bar analogy is a good one. Assuming the bond strength in a water molecule is roughly the same sort of order of magnitude as in a tough solid substance such as iron or steel, then it's plausible that pulling apart a blown-up water molecule say 10 cm across would be similar to trying to pull apart an iron bar of that diameter, which obviously would take a great deal of force. I don't know why, but somehow I was visualising that I would be able to pull it apart with my hands... 86.179.5.247 (talk) 23:36, 2 August 2011 (UTC)[reply]

Severed hands

If one's hand is sliced off, is he likely to bleed to death? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:46, 31 July 2011 (UTC)[reply]

Why not? Cutting you wrists seem to be an effective mode of suicide. Plasmic Physics (talk) 03:07, 31 July 2011 (UTC)[reply]

Unreliable sources have claimed otherwise. Also i remember reading a statement (admittedly online) about cutting wrists hardly ever resulting in anything more than a scar (paraphrased near quote). Whoop whoop pull up ^{Bitching Betty | Averted crashes} 03:11, 31 July 2011 (UTC)[reply]

Cutting ones wrists often does result in a scar for a few reasons. Someone might find the person, call the local emergency services, and save the person. The person may just be trying to get attention and do it in front of someone who then calls. The person may not do it well enough, pass out, it clots, and they're found. Often the person doing the cutting doesn't do it well enough to actually exsanguinate themselves, passes out, wakes up later, cries, and goes on with their life. What do you expect, they're amateurs and probably don't know that much about what they're actually attempting. Dismas|^(talk) 03:37, 31 July 2011 (UTC)[reply]

So, considering all that, what would completely severing the hand do? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 03:57, 31 July 2011 (UTC)[reply]

If no medical attention were given, and no attempt was made to staunch the flow of blood? Kill them. If drastic lifesaving measures were used, they may survive. --Jayron32 04:22, 31 July 2011 (UTC)[reply]

Agreed. The most immediate difference would be made by applying a tourniquet. StuRat (talk) 04:23, 31 July 2011 (UTC)[reply]

Really? What to Expect the Toddler Years claims that applying pressure to the wound is usually sufficient to staunch the flow of blood even in such extreme circumstances. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:32, 31 July 2011 (UTC)[reply]

That's what a tourniquet is, a means of applying pressure to an extremity, for the purpose of reducing the flow of blood. StuRat (talk) 06:04, 31 July 2011 (UTC)[reply]

As I understand it, there's a big distinction in practice. Usually a tourniquet doesn't apply pressure to the wound itself, but to the blood vessels upstream of the wound. Secondly, a tourniquet typically cuts off almost all blood flow to the extremity, as opposed to direct pressure to the wound itself which still allows blood flow to vessels not compressed (e.g. on the other side of the limb). "Use a tourniquet" is a much more drastic intervention than "apply pressure to the wound", and the two should not be treated as synonyms. -- 174.24.213.112 (talk) 18:03, 31 July 2011 (UTC)[reply]

In general, yes, but in the case of a severed hand, I can't see how you could "apply pressure to the wound". Does that mean you'd clamp a hand tightly over the end of the stub ? I can't see that working. Perhaps you could squeeze the arm tightly further up, though, which is precisely what a tourniquet would do. StuRat (talk) 18:24, 31 July 2011 (UTC)[reply]

I recently took a first aid course and they no longer teach tourniquets. They don't event teach the use of pressure points. Apparently, people tended to do more harm than good with them. Direct pressure and elevation are usually sufficient even in extreme cases. It's not difficult to apply direct pressure to the stump of an arm. If your hand is all you had available, then use it, but ideally you would put a large sterile dressing over it (perhaps using your hand to apply more pressure, since it would be difficult to tie a tight bandage in that location). If you don't have a dressing, you could take your shirt off and use that. In addition, you elevate the wound above the heart. That should be plenty to stop the bleeding. I have read that in cases of total traumatic amputation, the bleeding is actually quite small. If an artery is completely severed, it tends to contract, which slows the bleeding. --Tango (talk) 18:43, 31 July 2011 (UTC)[reply]

I even more recently took a first aid course as part of Scouting/Guiding. We talked about how tourniquets are no longer taught in more first aid courses, but also talked about the possibility (if you're letting the children take any sort of controlled risk, as we are supposed to) that you actually might need to, and that obviously we wouldn't use it just because someone was bleeding, but that if someone has lost a limb and/or is gushing blood so that a significant proportion is on the ground, and the ambulance is not here, your choice is basically tourniquet or dead child. If you let children use axes and saws, you can try to teach them safety and control the situation, but you also need to plan for the worst. It's all very well talking about the danger of cutting off circulation to flesh, but is someone is bleeding out and you can't stop it, they will die. So you try another way, and if it doesn't work and they are still bleeding catastrophically, you do what can save their life. We also talked about how the way we were taught to make a tourniquet as children ('as tight as possible') is the real problem, and that you should only tighten until the bleeding has just become slow enough to control, or just stopped if there's no other way to stop it. Catastrophic bleeding actually comes at the top of list of priorities for first aid, these days. You can't circulate oxygen around the body if there is no blood. 86.164.73.187 (talk) 20:35, 31 July 2011 (UTC)[reply]

Certainly, in a matter of life and death you do whatever you need to do to save the life. It's very unlikely that a tourniquet will ever actually be necessary, though. It only helps for bleeding limbs and try tend not to bleed that much. When people bleed out, it is usually from abdominal wounds. On my course they mentioned that when they had taught tourniquets, they taught people to release it every ten minutes for a few seconds to allow the limb to re-oxygenate. For anyone considering using a tourniquet, be aware that you could face legal action if you do it wrong and cause more harm than good, since it isn't a recommended part of first aid (so may not be covered by good Samaritan laws). --Tango (talk) 21:46, 31 July 2011 (UTC)[reply]

We also talked about litigation. We were told that it basically never happens, and that if it does we would rather be in the position of a live child with some disability than a dead child, and that the organisation would stand behind us if we'd taken reasonable action based on what we'd learnt. We were told that the bogeyman of 'I'll be sued for helping' is basically a myth in this country, and far more likely to lead to injury and death than us doing reasonable things. Again, these tourniquets were only if you'd tried everything else and it hadn't worked, and were just to reduce the pressure enough that you could use other techniques effectively. Tourniquets are still used in medicine, but much more carefully than in the past. If you're just trying to keep the blood inside until a paramedic arrives and takes over, we were told that tourniquets could indeed be a vapid part of our arsenal (just not used indiscriminately or over-tightly). 86.163.1.126 (talk) 15:56, 2 August 2011 (UTC)[reply]

Why on earth would I let my children use this?] Whoop whoop pull up ^{Bitching Betty | Averted crashes} 21:40, 31 July 2011 (UTC)[reply]

I'm removed the giant image you posted here of an antique horseman's axe because it was distracting and completely irrelevant.

It's perfectly normals for children to be allowed to use modern wood-cutting axes and hatchets with varying degrees of supervision. The Boy Scouts do it all the time. That's ages 10 through 18(In USA). And I'm sure kids who grow up on farms or out in the woods also learn to use those tools at an early age. But that doesn't really have anything to do with the question. APL (talk) 01:32, 1 August 2011 (UTC) [reply]

Don't forget to warn them to be careful with That Axe, Eugene...

Survival probably wouldn't depend on "drastic lifesaving measures". Some basic first aid would suffice. You're probably right, though, that left untreated it would be fatal.--Srleffler (talk) 04:47, 31 July 2011 (UTC)[reply]

Perhaps "immediate" would be a better term than "drastic". StuRat (talk) 06:05, 31 July 2011 (UTC)[reply]

Don't forget about cauterisation. Plasmic Physics (talk) 05:37, 31 July 2011 (UTC)[reply]

Now that really does seem "drastic", especially when done in the field with whatever hot object is handy and without any anesthetic. StuRat (talk) 15:45, 31 July 2011 (UTC)[reply]

OWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW! Whoop whoop pull up ^{Bitching Betty | Averted crashes} 15:57, 31 July 2011 (UTC)[reply]

Yes, do forget about cauterisation! It almost always does more harm than good. You would eliminate any chance of reattaching the hand (which is entirely possible with modern medical techniques - see microsurgery). Even if reattaching the hand wasn't going to be possible anyway, you would eliminate the chance of getting a clean stump without amputating more arm, which could make use of a prosthetic more difficult. There are also all the usual risks associated with severe burns, which can be life threatening. --Tango (talk) 18:43, 31 July 2011 (UTC)[reply]

It is extremely possible for a severed hand to develop some kind of infection which left untreated or the person has a weak immune system could possibly die from that. Bleeding to death is possible but its more likely to happen if both hands got severed which is hard for one person to do. --86.45.132.106 (talk) 20:41, 31 July 2011 (UTC)[reply]

I'm not sure I'd be that worried if the severed hand developed an infection - I'd be more worried about the parts still attached to the body... ;-) AndyTheGrump (talk) 02:26, 1 August 2011 (UTC)[reply]

Read about Aron Ralston. Bus stop (talk) 01:49, 1 August 2011 (UTC)[reply]

I never did understand why cauterization was presented as a first aid solution - infection in ancient times was so often a death sentence, and in modern times people know better. Hippocrates regarded it as a last resort: "What drugs will not cure, the knife will; what the knife will not cure, the cautery will; what the cautery will not cure must be considered incurable". My feeling is that only European civilizations from a few centuries ago could have been so ignorant of medicine as to rely on it to stop bleeding... Wnt (talk) 21:15, 2 August 2011 (UTC)[reply]

IR tech

Can an infrared or thermal imaging sensor detect a person buried under snow? 67.169.177.176 (talk) 03:59, 31 July 2011 (UTC)[reply]

It depends on the density of the snow and the sensitivity of the sensor. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:01, 31 July 2011 (UTC)[reply]

So a top-of-the-line IR sensor like those used by the military could do it easily, while a cheap $200 IR camera would be useless? Makes sense to me. BTW, am I right that you have an interest in aviation? 67.169.177.176 (talk) 04:11, 31 July 2011 (UTC)[reply]

Yup. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:30, 31 July 2011 (UTC)[reply]

Do you have an actual reference for this? Or are you completely making it up off the top of your head? APL (talk) 13:09, 31 July 2011 (UTC)[reply]

No need to cite the obvious... Whoop whoop pull up ^{Bitching Betty | Averted crashes} 16:33, 31 July 2011 (UTC)[reply]

If you said that about the specific claim on the encyclopaedia proper you would still find yourself challenged and the claim legitimately removed, and rightly so. Nil Einne (talk) 17:10, 31 July 2011 (UTC)[reply]

It would also depend on the depth of the snow and how long it has been in place. Right after an avalanche, the surface of the snow should be about the same temp everywhere, while, after some time, the snow near the body should be slightly warmer. StuRat (talk) 04:19, 31 July 2011 (UTC)[reply]

Unfortunately, by that time most of the victims would be dead. See Avalanche#Human survival and avalanche rescue. 67.169.177.176 (talk) 05:19, 31 July 2011 (UTC)[reply]

True, that's why I said "the body". So IR would likely only be useful for recovery of bodies, not for rescue. StuRat (talk) 05:59, 31 July 2011 (UTC)[reply]

Unless by some miracle someone is buried at a shallow depth (which means the snow warms faster) and/or has some kind of physiological traits that allow him/her to survive being buried without suffocating or freezing to death. (It seems there's always a case or two like that after any major building collapse {earthquake, 9/11, etc.}, and I've even read of one case where someone was dug up alive from an avalanche after being buried all day long.) Could be a good plot twist. 67.169.177.176 (talk) 08:25, 31 July 2011 (UTC)[reply]

You would need a passive microwave receiver to detect heat radiation from the body, at radio frequencies this travels through snow easily. These exist on some satellites, but I don't know if yo can get a hand held model. Graeme Bartlett (talk) 12:07, 31 July 2011 (UTC)[reply]

Thanks, but I'm looking for a helo-mounted model right now. (In any case, if you're looking for survivors on foot, then rescue dogs make a much better sensor.) 67.169.177.176 (talk) 01:32, 1 August 2011 (UTC)[reply]

Some burglar alarms contain them, so I don't see why not. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 12:49, 31 July 2011 (UTC)[reply]

Link please?

For me, Google is only turning up a couple of patents. But that's no help, since completely impossible things are often patented. APL (talk) 13:12, 31 July 2011 (UTC)[reply]

Here's a fun thread where this technology is discussed, one person, who claims to be a scientist studying exactly this says this about the equipment to find people with microwaves : "After decades of development, you currently need 2 skidoos, a sled, and 3 people to operate the proprietary equipment." APL (talk) 13:44, 31 July 2011 (UTC)[reply]

Perhaps we need to wait for the patents to expire so competition can kick in and provide a cheap, reliable, easy to use, and effective product. StuRat (talk) 15:19, 31 July 2011 (UTC)[reply]

Better yet, pay someone in the Patent office to revoke the patents. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:45, 31 July 2011 (UTC)[reply]

Oh, my, the things I would do with a portable terahertz imager and a powerful tunable terahertz maser. Find people under snow, look at the neighbors naked in their beds, reprogram their skin to make fetal keratin and blister up all over their bodies... so many possibilities, so little time. Someone has this equipment... Wnt (talk) 01:25, 1 August 2011 (UTC)[reply]

fart. Erm, flatulence

~~Exactly what is a fart composed of? Oh, that's obvious, it depends on what you eat/drink/do/say/whatever, but w~~ What is the general base for a fart? Is it true that one can fart next to a lighter and get the fart fire cloud thingy? An editor since 10.28.2010. 05:37, 31 July 2011 (UTC)[reply]

a) It varies, of course, but Hydrogen, Methane, and 'air' (Nitrogen, Carbon dioxide, Oxygen)

b) Methane and Hydrogen burn explosively, so yes; it can also lead to burns, and a trip to hospital.

Wikipedia covers it, in a) Flatulence#Composition of flatus, b) Fart lighting. Chzz ► 05:50, 31 July 2011 (UTC)[reply]

Thank you. Chzz saves the day again --Since 10.28.2010 05:53, 31 July 2011 (UTC)

YouTube used to have videos of people lighting their farts. Don't know if there are still any around. Dismas|^(talk) 13:05, 31 July 2011 (UTC)[reply]

Adam Savage did it on Mythbusters (Episode 48 outtakes). — Michael J 06:45, 1 August 2011 (UTC)[reply]

Cymbal-eared aliens

If a species of aliens had big ears shaped like cymbals, at the sides of their heads, what would their hearing be like? Megaconworlder (talk) 08:40, 31 July 2011 (UTC)[reply]

Out of this world?--78.148.142.14 (talk) 10:54, 31 July 2011 (UTC)[reply]

Not very good, cymbals are mostly flat except at the centre. Sound wouldn't be focused very well by cymbal shaped ears. Plasmic Physics (talk) 11:55, 31 July 2011 (UTC)[reply]

See pinna (anatomy).--Shantavira|^{feed me} 12:50, 31 July 2011 (UTC)[reply]

Cymbals are not mostly flat, by the way. They may lok that way from afar or on TV but they are actually almost never flat. It's much more obvious if you see from beneath. Beeblebrox (talk) 22:04, 31 July 2011 (UTC)[reply]

True, but probably still not a good shape for an ear. There's no focal point. APL (talk) 02:10, 1 August 2011 (UTC)[reply]

OK, conical. A cone is still flat along a generatrix, meaning there is still no focal point for the conical section. The central buldge however, does have a focal point. Essentially, the large conical outer section of the cymbal has no effect on sound focussing, and is superfluous. They are incorporated for a different purpose in the musical instrument, to improve tintinnabulation qualities. Plasmic Physics (talk) 14:07, 1 August 2011 (UTC)[reply]

NATO notation for color specification?

The Wikipedia page on the Union Flag has a section on its color specification. One of the specifications is in some “NATO” notation (e.g. “8305.99.130.4580” for the blue color of the flag). What color notation is that? --98.114.98.196 (talk) 13:07, 31 July 2011 (UTC)[reply]

NATO Stock Number - see the link. The wikilink in the article to the North Atlantic Treaty Organization was misleading; I'll change it. Chzz ► 16:04, 31 July 2011 (UTC)[reply]

HRT self-medication

I want to learn about HRT self-medication. Specifically, do people who do it buy the medication online or do they extract it from shop bought products? Please, spare me the "it's dangerous go see a doctor" speech; I'm not a transsexual and I've no plans to self-medicate. I'm just curious about how it's done. — Preceding unsigned comment added by 78.126.136.91 (talk) 14:55, 31 July 2011 (UTC)[reply]

Perseids, August 2011

Hi! I've been watching the Perseids for a few years now. The peak of this year's meteor shower is 13 August. However, full Moon also comes that night and will ruin the show. My question is: what night should be perfect for watching the Perseides if we consider both the peak of the shower and the moon phase (but not the weather)? 92.36.179.99 (talk) 16:17, 31 July 2011 (UTC)[reply]

Well, according to our Perseids article, the best viewing is in the pre-dawn hours, and to get darkness during that period you should watch a couple of days before the full moon. But if you don't want to be watching for meteors at 4 AM, you might prefer to watch a couple of days after the full moon, when it will be dark for a while after the sun sets. (I hope I got that right; I always have trouble with moon phases.) Looie496 (talk) 17:43, 31 July 2011 (UTC)[reply]

The very best time is still August 12 / 13, but after the moon sets. Because the moon is full there is only a small window when it will still be dark after the moon sets. At my location in the US, that gives a couple hours immediately before dawn. Dragons flight (talk) 17:51, 31 July 2011 (UTC)[reply]

Ciências - Química

Scientific American: A reportagem refere-se ao Sequestro de Carbono presente na atmosfera por meio de tubulações especiais, sendo devolvido ao subsolo em alta profundidade para ser reabsorvido, tornando-se útil novamente em um futuro distante, em forma de gás ou até mesmo de Petróleo(?). Qual seria a certeza científico-tecnológica da eficácia de tal procedimento? — Preceding unsigned comment added by 200.103.171.184 (talk • contribs)

The question refers to carbon sequestration. But we aren't going to answer in Spanish, and I don't see that point in an answer the OP won't be able to read. Looie496 (talk) 17:25, 31 July 2011 (UTC)[reply]

That's not Spanish. It's Portuguese! Portuguese happens to be my mother tongue, so you can take my word for it. For a second I didn't even realize that the question was not in English since I can read either of them effortlessly. He is asking if it is true that carbon dioxide re-inject underground might turn back into natural gas or oil in a distant future. Dauto (talk) 18:38, 31 July 2011 (UTC)[reply]

Well then, no. There's nothing to reduce or hydrogenate the carbon dioxide before it diffuses into rock fractures and sedimentation. 208.54.5.187 (talk) 20:36, 31 July 2011 (UTC)[reply]

Translation to Portuguese: Não porque não há como reduzir ou hidrogenar o dioxido de carbono que simplesmente se difundirá pelas rochas e sedimentos. Translated by Dauto (talk) 21:23, 31 July 2011 (UTC)[reply]

Agreed. Translation to Portuguese: Concordo. Dauto (talk) 21:23, 31 July 2011 (UTC)[reply]

Kepler’s 3rd law

Assuming the Kepler’s 3rd law is valid at the atomic level do the electron shells follow Kepler’s 3rd law? --DeeperQA (talk) 23:59, 31 July 2011 (UTC)[reply]

It sounds like you are using the old Dalton model of the electrons as little spheres which orbit the nucleus just like planets orbit the Sun. The modern conception is more that electrons exist as probability clouds, so classical orbital mechanics don't really apply, no. StuRat (talk) 00:06, 1 August 2011 (UTC)[reply]

No, I am aware that an electron cloud might even be a field but nevertheless what I am asking is whether the shells, in any regard, are related by two factors such as semimajor axis and period of orbit. --DeeperQA (talk) 00:21, 1 August 2011 (UTC)[reply]

The answer is no, electron "shells" have nothing at all to do with orbiting, even though the term "orbital" is used. Electrons don't "orbit" in the same way that a planet orbits a star; distance from the nucleus is described by a variation of the Rydberg formula, but this "distance" isn't the same thing as the "distance" a planet orbits from the sun. There is no correlation because its a completely different concept. If you want to get beyond a grade-school understanding of electrons, you need to let go, in every way, the idea that the electron is a little ball racing little circles around the nucleus. It works nothing like that. --Jayron32 01:19, 1 August 2011 (UTC)[reply]

I wouldn't say that. All the QM formulas started by working with classical concepts. The electron has an angular momentum, which matches where it is and "how fast it is orbiting"; it can't exceed the speed of light while orbiting as we discussed with end of the periodic table. It just isn't really a nice neat little ball, but a sort of wave of probability. Now looking up Kepler's third law, "The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit." Now the infamous Bohr model gives orbital radius (they're circular) proportional to the square of n; the velocity is proportional to the inverse of the square root of the radius (and thus 1/n); so the period (circumference / velocity) should be proportional to n cubed. That means that the radius : period is indeed square : cube, just like in Kepler's law. Bohr's model gives real results for hydrogen atoms, so it's not irrelevant. Now quantum mechanics and the Schroedinger equation involve more complex terms for interactions between charges, and end up resorting to numerical methods for solution, but the three-body problem isn't really so tractable even in orbital mechanics. Also note: Rydberg atoms (i.e. atoms that are almost but not quite ionized, with electrons orbiting a nucleus at a great distance) actually do have electrons moving in "Keplerian elliptical orbits", according to the article. Wnt (talk) 02:15, 1 August 2011 (UTC)[reply]

In most cases Kepler's equations cannot be used to make predictions about the orbits of electrons. Excepting some special cases as mentioned above.

Electrons orbiting a nucleus...

Cannot be described as solid particles.
Do not orbit the nucleus in the sense of a planet orbiting the sun, but instead exist as standing waves.
Are never in a single point location, although the probability of interacting with the electron at a single point can be found from the wave function of the electron.
Jump between orbitals in a particle-like fashion. For example, if a single photon strikes the electrons, only a single electron changes states in response to the photon.
Retain particle like-properties such as: each wave state has the same electrical charge as the electron particle. Each wave state has a single discrete spin (spin up or spin down).

"Despite the obvious analogy to planets revolving around the Sun, electrons cannot be described as solid particles. In addition, atomic orbitals do not closely resemble a planet's elliptical path in ordinary atoms. A more accurate analogy might be that of a large and often oddly-shaped "atmosphere" (the electron), distributed around a relatively tiny planet (the atomic nucleus). One difference is that some of an atom's electrons have zero angular momentum, so they cannot in any sense be thought of as moving "around" the nucleus, as a planet does. Other electrons do have varying amounts of angular momentum."

see Atomic orbital.

Electrons are odd ducks that are not ducks. - ArtifexMayhem (talk) 03:26, 1 August 2011 (UTC)[reply]

The atomic orbitals derive from the same Hamiltonian that classically gives you the Keplerian orbits, so some probabilistic variant of Kepler's laws must apply to them, but I'm not sure exactly how it works. The classical orbits and quantum orbitals are closely related.

That d-orbital image is terrible. The five individual orbitals are badly hand-drawn (compare this), and the "combination" orbital is complete nonsense. A combination of all orbitals of a given type should look like a sphere, if it looks like anything. I can't believe that image is being used in major mainspace articles after all these years. Surely there's something better on Commons. -- BenRG (talk) 08:00, 1 August 2011 (UTC)[reply]

Clearly orbitals involve quantum weirdness - one way to think of this is to note that the orbital structure is not actually linked to the atom, but to the observer. As I understand it, if you determine an electron is in one particular p orbital, and you change your viewpoint by 45 degrees along one of the axes you've defined, it now has equal odds of being in two different p orbitals according to your new coordinate system. Even so, I wouldn't go so far as to say that an electron in an s orbital has no angular momentum - after all, it has spin angular momentum, which inevitably involves the electron's cloud-like essence going in a circle of some sort around the nucleus. Wnt (talk) 21:03, 1 August 2011 (UTC)[reply]

August 1

Block erasure

Why can flash memory be read and written one cell at a time, but only erased in blocks? I've read the flash memory article, and it seems that erasure is just a matter of bringing the control gate low and the drain high, which doesn't seem any more complicated than programming the bit. --140.180.16.144 (talk) 00:19, 1 August 2011 (UTC)[reply]

It is a different mechanism. Imagine a flash memory made up of buckets of water. You can ask whether any particular bucket is full. You can fill any particular bucket. Or you can pull the "single" bit of string that opens the bottom of a whole block of buckets to erase the block. Obviously it could be done differently, but memory manufacturers have decided that the block erase method is a commercially satisfactory compromise between being unable to erase at all and being able to erase any particular cell. -- SGBailey (talk) 11:40, 1 August 2011 (UTC)[reply]

Disulfiram and fetal alcohol syndrome

I had an episode "Choice" going in the background, where a pregnant woman ends up being sentenced to a court-ordered alcohol treatment program to avoid fetal alcohol syndrome. I became curious whether the notoriously unpleasant combination of Antabuse (disulfiram) and alcohol would increase the risk of FAS, and found some references suggesting that acetaldehyde, which is what builds up when the drug is taken to interfere with alcohol degradation, does indeed have teratogenic effects,^[8][9] though one study found that disulfiram didn't make these worse.^[10] All these studies were quite old, and seemed to mark this as a question of some public health importance, yet I'm reading that disulfiram has remained "FDA pregnancy category C" with no information about whether it is harmful or not to pregnant mothers. How is it that this question has never officially been sorted out one way or the other? Wnt (talk) 01:21, 1 August 2011 (UTC)[reply]

Prob'ly 'cause it takes a long, long time to do clinical studies in humans. FWIW 67.169.177.176 (talk) 01:43, 1 August 2011 (UTC)[reply]

Well, you certainly can't do a proper clinical trial to look for teratogenicity in fetuses - but you can look retrospectively at what happens when the mother chose to take the drug vs. not, with certain pitfalls. Wnt (talk) 01:50, 1 August 2011 (UTC)[reply]

Insane to order her to go on antabuse when she could be incarcerated for nine months and given valium to control the withdrawal symptoms. Rather silly premise. μηδείς (talk) 02:00, 1 August 2011 (UTC)[reply]

Incarcerated on what charge? I don't think I saw the episode, but the brief description at the linked article doesn't mention any criminal act on her part. --Trovatore (talk) 08:19, 1 August 2011 (UTC)[reply]

Sorry - this wasn't really a question about the episode, which never specifies what sort of treatment would be given at all. It just got me wondering whether authorities, one place or another, might be causing fetal alcohol syndrome with their forceful efforts to prevent it. Wnt (talk) 17:11, 1 August 2011 (UTC)[reply]

popularizing chemistry

I feel that many natural science branches like biology and physics are more popularized than chemistry.Am I wrong?If so, why is chemistry less popularized? Is it hard or something?--Irrational number (talk) 01:26, 1 August 2011 (UTC)[reply]

I dunno -- as a chemist, I don't find it hard at all. Maybe it's just that there's not as much earth-shaking basic research (as opposed to the more mundane but more useful applied research)? 67.169.177.176 (talk) 01:37, 1 August 2011 (UTC)[reply]

I think that there's a lot more biology being publicly funded than chemistry, which I think of as being done much more by corporations. Public funds encourage researchers to talk up (if not hype) their research to the public, whereas proprietary research tends to be done in secret, and when discussed by company employees, tends to be disbelieved by a skeptical public. Wnt (talk) 01:41, 1 August 2011 (UTC)[reply]

Plus, there are negative stereotypes of chemistry being a "dirty" science (as opposed to biology, which is "natural" and therefore supposedly "green"). 67.169.177.176 (talk) 01:45, 1 August 2011 (UTC)[reply]

I would be quite surprised if there was any correlation with amount of public funding received and amount of popularization. The areas of popularization are fairly narrow (a handful of sub-questions of each field, even in physics and biology), whereas the areas of public funding are quite broad. Furthermore, it isn't the case that popularizing your particular discipline (say, physics) is going to result in increased public funding for that discipline, as generally speaking most public funding of science goes into a big NSF pot that is then doled out by the NSF administrators and reviewers, not Congress or "the public" to any degree (and let's thank goodness for that!). --Mr.98 (talk) 01:55, 1 August 2011 (UTC)[reply]

This is quite an esoteric question - no way to clearly say exactly which part fits in which branch, and so forth. And, it depends what timeframe you look at, what countries you look at, all the problems of cross-field-studies (is astrophysics chemistry? Molecular modelling? etc) Depending on how you choose to divvy up "The Sciences", you'd get vastly different results. A related article, which might serve as a starting point, is Natural science. Personally, I don't think it is related to difficulty; it could relate to trend/fashion, and could relate to the way subjects (for e.g. Degree-level) are constantly being subdivided. I bet there's a bit of Chemistry included in various Quantum mechanics courses, and in a cooking degree. Is a chef a chemist? Chzz ► 01:51, 1 August 2011 (UTC)[reply]

In the United States, physics started being really popularized initially after WWII, because of its association with wartime weapons. In more recent years its ability to tell stories about our origins (e.g. cosmology) kept it relevant in the popular mind, and the "mind-blowing" aspects of quantum and relativity make for rather heroic (if often misunderstood) narratives. Biology is mainly popularized via discussions of evolution and genetics, both of which are quite popular in that they again tell stories about our origins and our current selves. Genetics has been of popular interest in the US since the 1920s or so, in part because of its connection with eugenics and race and all that, which really touch pretty deep into major American preoccupations. As for chemistry, there just doesn't seem to be as much popular association. In the best of times it is associated with industry and development; in the worst of times, with all of the excesses and downsides of industry and development (pollution, DDT, whatever). The aspects of it that do pertain to origin stories or selfhood quickly become assimilated into other fields (e.g. cosmology, again). Chemistry does not appear to tell very heroic stories about humanity or its place in the universe, though there is no inherent reason it need not. --Mr.98 (talk) 01:52, 1 August 2011 (UTC)[reply]

Here in Australia we have a major political leader who has publicly declared twice in the last week that carbon dioxide is difficult to detect because it's invisible, tasteless, odourless and weightless. That he was able to say it twice without embarrassment shows the poor public situation chemistry is in. HiLo48 (talk) 01:58, 1 August 2011 (UTC)[reply]

Wait til he finds out about the insidious chemical, dihydrogen monoxide. :-) StuRat (talk) 02:31, 1 August 2011 (UTC) [reply]

Common name, "Copious water"; always labelled "use sparingly" ;-) Chzz ► 06:54, 1 August 2011 (UTC)[reply]

Simplistic answer: Because as far as the environmentalist, organic food and natural health "industries" (both the crackpot and nominally rational varieties thereof) are concerned, chemistry is the Great Satan!(tm). The major selling point for much of food and "natural" medicines and other products advertising is the claim that they "contain no chemicals" and the gullible uneducated public swallow it whole. The chemical industry has simply been totally and utterly crushed in the propaganda war for public consciousness - probably because they never even noticed there was a war on until after they had already lost it. Roger (talk) 11:29, 1 August 2011 (UTC)[reply]

Did anyone tell him carbon monoxide, radon, sarin and a number of other substances he probably does want someone to regulate are also odourless, 'invisible' (presuming this means colourless) and tasteless? Nil Einne (talk) 01:36, 3 August 2011 (UTC)[reply]

DNA testing of cremains

On a past set of episodes of the show Dexter, the forensics people performed DNA testing on a very small amount of cremated remains and were able to compare its DNA with the DNA from some nearby saliva and determine the two people were related. Is it actually possible to perform any useful DNA analysis on ashes? To forestall a particularly useless type of response seen pretty often on the Reference Desk, I will note in advance: Yes, I am aware that teleplays are works of fiction, and that authors of fiction often write things that are not possible. Comet Tuttle (talk) 02:50, 1 August 2011 (UTC)[reply]

Only if the cremation was done improperly. When a murderer splashes gasoline on a body and lights a match, for example, lots of DNA will likely remain. StuRat (talk) 02:57, 1 August 2011 (UTC)[reply]

(edit conflict)Doing a google search, I have found private companies that will take your money to do it for you: Here is but one example. However, others debate that this is normally viable in a properly done cremation: This page says that it isn't possible; This page says that it may be possible if teeth survived the cremation process. Neither of those are what I would call scrupulously reliable, but the College of American Pathology at least has a name that sounds credible, and they say that under normal cremation conditions, there is no way to get DNA. Apparently DNA can survive a "few hundred degrees" for a short time; the reference notes the possibility of recovering DNA from building fires, but cremation conditions (in excess of 2000 degrees C for in excess of 2 hours) doesn't leave anything behind. --Jayron32 03:04, 1 August 2011 (UTC)[reply]

Great references - thanks, Jayron32! Comet Tuttle (talk) 16:30, 1 August 2011 (UTC)[reply]

energy solution

Suppose public land in each County could be set aside and populated with solar farms and energy storage devices to form a giant power grid sufficient to supply all of the electricity needs of the United States and that this could be done for substantially less cost than the 14 trillion dollar deficit. Is there any reason why this could not be done immediately? --DeeperQA (talk) 04:45, 1 August 2011 (UTC)[reply]

Sure, you want to clear all of the nature off of the little bits of greenspace we have left? Turning earth into Coruscant doesn't sound like all that great of an idea... --Jayron32 04:54, 1 August 2011 (UTC)[reply]

Besides all other reasons, it is a long term solution, in the short term, it would only make the deficit grow. Plasmic Physics (talk) 04:56, 1 August 2011 (UTC)[reply]

Sorry, I did not think it necessary to mention that I am looking for scientific rather than financial or contrived reasons. For instance their are plenty of ways to avoid using green space which produces a little be of oxygen and if you can get rid of the deficit budget and opt for a surplus budget then you can solve two problems with one action. Please try again. --DeeperQA (talk) 05:06, 1 August 2011 (UTC)[reply]

So, you've invented a magical world where considerations like money and the environment don't matter, and you're asking us to critique it? With infinite resources and no financial or environmental concerns, you could do anything. By your criteria, you could set up a power grid based on hamster wheels if you wanted. Your solar system could be built if you had literally no other concerns at all. Back here in the real world, these concerns are important... --Jayron32 05:15, 1 August 2011 (UTC)[reply]

No need to be sarcastic, you could just have said that you don't perseive any scientific barriers, and that all the possible barriers are economical and evironmental in nature. (or something along these lines) Plasmic Physics (talk) 06:13, 1 August 2011 (UTC)[reply]

No. What I am asking is that you consider the end results and whether the end results would be sufficient to overcome real world difficulties instead of artificial difficulties such as already mentioned. --DeeperQA (talk) 06:05, 1 August 2011 (UTC)[reply]

Okay, how about this... Instead of going to Mars how about constructing such a grid? Would not that be a better project? --DeeperQA (talk) 06:18, 1 August 2011 (UTC)[reply]

Better in terms of what? Plasmic Physics (talk) 06:22, 1 August 2011 (UTC)[reply]

You name it. --DeeperQA (talk) 06:35, 1 August 2011 (UTC)[reply]

...err, I will rule out one: dealing with the aftermath of a giant asteroid hitting the US and blocking the radiation from the Sun. --DeeperQA (talk) 06:38, 1 August 2011 (UTC)[reply]

What I mean is, how are you comparing going to Mars against constructing such a grid? I frankly don't know what you want us to tell you. Plasmic Physics (talk) 07:10, 1 August 2011 (UTC)[reply]

I can not explain my question further. It seems clear to me that solar offers a global solution to energy needs and that cost can be handled in many ways. That leaves only the question of whether the science and technology at this point in time is sufficient to begin such a project now rather than wait until the only place to live is in outer space. --DeeperQA (talk) 08:25, 1 August 2011 (UTC)[reply]

I think if you have all these trillions of dollars available, investing in nuclear fusion would be a more assured long-term solution to energy supply, though there would be a longer delay before the investment paid off. Dbfirs 08:13, 1 August 2011 (UTC)[reply]

Obviously you can not create a 14 trillion dollar deficit unless the resources are available to do so and Chernobyl and Fukushima are good reason to avoid conventional fission based nuclear perhaps except for Thorium based fission rectors. --DeeperQA (talk) 08:25, 1 August 2011 (UTC)[reply]

If, like you said resources is not an issue, then either a massive scale solar project and colonising space are both possible projects. But, I'm not such what colonising space has to do with the USA's deficit problem. Plasmic Physics (talk) 09:06, 1 August 2011 (UTC)[reply]

Except as a questionable expenditure probably nothing. --DeeperQA (talk) 09:10, 1 August 2011 (UTC)[reply]

If you're looking to save the US budget by cutting NASA...I got news for you bud: NASA is a drop in the bucket. Its entire yearly budget is less than the military spends on air conditioning. NASA has arguably contributed more scientific innovations than any other organization in the world. There are better things to cut than scientific progress and research that is constantly bettering ALL our lives. How about we cut out some "fraud, waste and abuse"?-RunningOnBrains^(talk) 16:10, 1 August 2011 (UTC)[reply]

I agree, like tax breaks, tax cuts and tax loopholes for the rich. --DeeperQA (talk) 07:57, 2 August 2011 (UTC)[reply]

However, with electricity too cheap to measure a surplus budget could follow and forever be maintained in absence of perhaps anything except wise Chinese leader. --DeeperQA (talk) 09:13, 1 August 2011 (UTC)[reply]

That would be highly optimistic, even if you could do it for free like you said. Plasmic Physics (talk) 10:17, 1 August 2011 (UTC)[reply]

What does the US national debt have to do with it? The US government doesn't pay for people's energy. People pay for it themselves. In fact, the government gets a lot of revenue from taxes on energy. --Tango (talk) 11:42, 1 August 2011 (UTC)[reply]

The national debt is in the way. --DeeperQA (talk) 16:00, 1 August 2011 (UTC)[reply]

How is the national debt in the way? The U.S. is a free-market economy, not a socialist economy, and the government takes no part in the funding or building of industries, including power plants and the electrical grid. The national debt makes not one iota of difference in this matter... --Jayron32 00:34, 2 August 2011 (UTC)[reply]

The Manhattan Project gave us a fast track to nuclear power. It was government funded. The TVA project was government funded. Hover Dam project was government funded. The list can continue and is very long. --DeeperQA (talk) 07:55, 2 August 2011 (UTC)[reply]

I just did a back-of-the-envelope calculation and came up with a cost of about 10 trillion dollars for enough solar panels to provide all the US's electricity, at current prices. (Don't take that number too seriously, though.) The reason it could not be done immediately is that at current efficiencies, it would require at least 10,000 square kilometers of solar panels, which could not be constructed in a short time. Looie496 (talk) 16:09, 1 August 2011 (UTC)[reply]

Current solar technology is crap. They only convert a small portion of the sunlight to electricity, steadily decrease in efficiency, must be cleaned of dust regularly, have no ability to store the electricity until needed, cost too much, must be turned constantly to face the Sun, etc. Improving the technology is the first step required. In the meantime, there are other energy sources which are ready to be built now, such as nuclear reactors built in safe places, like underground in unpopulated areas, rather than above ground, in heavily populated areas, right by active fault lines. With a high enough level of incompetence, any energy source can be made dangerous. StuRat (talk) 16:23, 1 August 2011 (UTC)[reply]

Solar thermal energy is not so terrible as all that, but yes, there's a capital cost. Wnt (talk) 17:04, 1 August 2011 (UTC)[reply]

better fit?

Does Kepler's 3rd Law of Planetary Motion find a better fit if it is changed from p^2 = a^3 to p^2 = a^pi(3.141593...)? --DeeperQA (talk) 09:55, 1 August 2011 (UTC)[reply]

If it did, wouldn't the be stated as such? Plasmic Physics (talk) 10:21, 1 August 2011 (UTC)[reply]

Kepler's 3rd Law is already a perfect fit (under Newtonian gravity and mechanics). It follows by a pretty simply mathematical derivation from F=GMm/r² and F=ma. If you want to allow for relativity then just changing the power isn't going to help at all. --Tango (talk) 11:45, 1 August 2011 (UTC)[reply]

No, of course it doesn't. The question is what makes you think it should or could? Dauto (talk) 13:02, 1 August 2011 (UTC)[reply]

I was thinking only about planetary orbit approximations and not about mathematical derivatives. I see it: 2*G*M*m/r^3 from G*M*m/r^2. Thanks. --DeeperQA (talk) 14:50, 1 August 2011 (UTC)[reply]

You should look into the modern derivation of the law - I was just talking about something like it with electrons. While Kepler's third law might once have been determined by observation, we now know that the radius of an orbit is proportional to the square of the angular momentum of the object, and the length of time it takes to complete that orbit (the orbital period) is proportional to the cube. It's not some arbitrary ratio we can just change or adjust; each of these things is the necessary mathematical consequence of other physical laws. Wnt (talk) 17:07, 1 August 2011 (UTC)[reply]

You are right. Its called creative thinking (or speculation) which happened before first coffee and was applied out of place. I must have been asking myself how Kepler came up with the law using empirical data before the Calculus was invented. As for going deeper, yes, it is angular momentum that I was looking for to better connect the third law to electron orbits (atoms) but what my ultimate question is, is whether Kepler's third law is (or can be) applied to subatomic partials or are subatomic particles not regarded in terms of orbits? --DeeperQA (talk) 21:57, 1 August 2011 (UTC)[reply]

...Which has already been answered. No. Plasmic Physics (talk) 08:55, 2 August 2011 (UTC)[reply]

Statistics on Human Penis Size

Most of the charts I've seen look at stats for length or girth by themselves, I was wondering if there was any availible stats on both together. For example, what percentage of men have 6 inches length and 4 inches circumference, etc. 209.252.235.206 (talk) 10:32, 1 August 2011 (UTC)[reply]

I don't know the answer, but have you read "Human penis size"? There are several references. One of them might have your answer. Axl ¤ [Talk] 06:20, 2 August 2011 (UTC)[reply]

What is an airlift system

Apparently fish are moved up the Haneji Dam using an airlift rather than a fish ladder. I've seen and understand a fish ladder. What is how does an airlift work? Is it an Airlift pump? If so, don't the bubbles harm the fish? -- SGBailey (talk) 11:33, 1 August 2011 (UTC)[reply]

I think "air lift" may be an artefact of the dam's page's Janglish (which also calls a fish ladder a "stared-fish ways") rather than a correct technical term. It may simply be some kind of pumped siphon system; this company has a bunch of fish-sucking equipment including a siphon fish ladder. I can't find specific information about what's deployed at Haneji. -- Finlay McWalter ☻ Talk 13:47, 1 August 2011 (UTC)[reply]

Current Control vs. Voltage control

Hello. I am currently reading up on cochlear implants, but had little luck in finding different control mechanisms. What are some advantages of current control vs voltage control (for cochlear implants specifically, but also in general) ?

Many thanks. 114.77.39.141 (talk) 11:53, 1 August 2011 (UTC)[reply]

This paper gives some of the answers. --Heron (talk) 17:33, 1 August 2011 (UTC)[reply]

Resurecting extinct species

Could species like the saber-toothed tiger or the mastodon be resurrected? There are some similar species which could get a genetically modified fetus contained the genome of them.Quest09 (talk) 12:15, 1 August 2011 (UTC)[reply]

There has been some talk of cloning up a moa (brief mention) and the Pleistocene Park guy wants a woolly mammoth. Right now we can clone mammals from a living cell: cloning up an extinct animal presents two major additional problems - firstly is getting a viable genome from something that has been dead for hundreds or thousands of years (that's surely easier for recently extinct things like the dodo and the thylacine than for mammoths, never mind dinosaurs), and secondly getting that genome into an egg and getting a clone to take from it. -- Finlay McWalter ☻ Talk 13:19, 1 August 2011 (UTC)[reply]

Mammoths have the advantages of being recently extinct as well as having lived in cold areas. Therefore, intact flesh of a mammoth may be found in the Siberian permafrost. However, DNA may still be found in bones and teeth of animals only a few thousand years old, provided they were properly preserved. This usually means they were encased in rock, before decomposition could work it's way into the interior of the bones and teeth.

Also note that finding a surrogate mother can be tricky, for mammals larger than any living today. Perhaps a mammoth could be placed in an African elephant, or a saber-toothed tiger in a Siberian tiger, but a c-section would be needed before the offspring became too large, with "premie" medical care performed after that. Birds are easier, as you only need an incubator for the eggs. You'd just have to guess at the ideal temperature, though. StuRat (talk) 16:02, 1 August 2011 (UTC)[reply]

Don't the eggs need to be laid? -- 203.82.81.54 (talk) 20:41, 1 August 2011 (UTC)[reply]

Yes: part of the problem of using a surrogate mother of another species is that there is a great deal of interaction between the physiologies of mother and festus during gestation, so by virtue of their being different species, mismatches fatal to a successful gestation are likely, and even if the fetus is successfully born, it likely won't have developed in quite the same way as if it had been gestated in a mother of its own species. Incidentally, the loose term Sabre-toothed tiger covers several families of extinct mammals, none of which were anywhere near as closely related to the modern Tigers as, say, modern Lions. Similarly, Mastodons were not even in the same family as modern Elephants, and Mammoths were in the same family but not either of the same genera, so again the relationships are less close (though genetic closeness is not completely correlated with the "distance" of these taxonomic ranks), and the barriers likely to be greater, than is popularly supposed. {The poster formerly known as 87.81.230.195} 90.201.110.81 (talk) 19:50, 1 August 2011 (UTC)[reply]

Interaction between "mother and festus" ? I hate to picture that interaction: [11]. StuRat (talk) 10:46, 2 August 2011 (UTC) [reply]

The interaction is limited, though, otherwise offspring with mothers of different blood types would not be viable, and male offspring would be thoroughly messed up by the female hormones of the mother, all being born with female genitalia. StuRat (talk) 10:49, 2 August 2011 (UTC)[reply]

Hemolytic_disease_of_the_newborn, and I've read of interesting studies on younger sons having a less comfortable time in the womb than older sons, due to the whole male/female thing (I can't remember enough to find an article though). Do we have an article on the battle between the mother and fetus? And this is all within one species, a species with little genetic variability. This is a completely different scale to the problems with different species, or different genera, or even different families. 86.163.1.126 (talk) 13:16, 2 August 2011 (UTC)[reply]

If mother and baby have different blood types, then mixing of the blood may be fatal to the baby. That's as bad as it gets, same species or different. In rare cases this does happen, but obviously most of us survive, due to the placental barrier. I don't understand your "young son"/"older son" comment. Also, for other examples of cross-species reproduction, look at grafting in trees, and hybrid animals, like the mule/hinny or tiglon/liger. StuRat (talk) 13:44, 2 August 2011 (UTC)[reply]

Most of us do not survive. I cannot remember enough about the son thing to link to a fuller explanation. Basically, it was found that as a woman had more sons, she was in some sense 'primed' to reject the male hormones (as I recall, I read this years ago), and her womb became a more hostile place for subsequent sons. The whole thing about the battle for resources between mother and child, and the interaction between them that battles at the edge of parasitism, is mainstream. 212.183.128.5 (talk) 15:04, 2 August 2011 (UTC)[reply]

Leptinella/Cotula

Hi there,

I am a very keen gardener from Newcastle, NSW Australia. I have no botany training at all, but I am interested in plants (Australian natives in particular). I bought a plant called Cotula purpusilla and I have been trying to sort out whether it is native to Australia or not. On the Wiki pages for Cotula and for Leptinella the information is a bit confusing as to which plants are called what and why there has been a change in the names and whether or not the changes have been accepted or not. And I still don't know whether my plant is native to Australia or not!

Don't get me wrong - I love Wiki! I guess it is just frustrating when the information given seems a bit muddled (in regard to the names). I suppose the other thing that would be really helpful on the plant info. pages would be to ensure that plant's country/state of origin as well as natural habitat is included.

Thanks so much for your time and effort, Fmcrowe (talk) 12:17, 1 August 2011 (UTC)[reply]

This page and others (note the correct spelling of perpusilla) indicate that the plant is native to New Zealand. This page says that the binomial name is a synonym of Leptinella pusilla. When taxonomists try to split or combine taxa, the results are often confusing. Deor (talk) 12:48, 1 August 2011 (UTC)[reply]

Weedicides

How does a weedicide know which is the required plant and which is the useless, unwanted plant? I asked this to my biology teacher but she too couldn't answer me. ID: (email removed) Name: Divesh Paryani — Preceding unsigned comment added by 41.58.128.95 (talk) 14:42, 1 August 2011 (UTC)[reply]

It doesn't. Many weedkillers kill all green plants, but common selective weedkillers tend to have little effect on plants of the grass family. Some crops are genetically modified to be resistant to general weedkillers such as glyphosate. The article on Herbicide might be of some interest, but it doesn't explain the biochemistry of resistance. Dbfirs 15:46, 1 August 2011 (UTC)[reply]

Glyphosate kills plants because it inhibits an enzyme involved in amino acid biosynthesis. (Humans and other animals aren't killed by it because we get such amino acids from our food - an option a plant doesn't have.) Glyphosate resistant (e.g. "Roundup Ready") plants, for the most part, have been modified with a different version of the enzyme (usually from bacteria) which isn't inhibited by glyphosate. In the presence of glyphosate, they can use this other enzyme to make the amino acids. Likewise with glufosinate (Liberty/Basta), which inhibits a different amino acid synthesis gene, which is also replaced/supplemented in resistant plants (e.g. "LibertyLink"). Other specific herbicides function the same way. For example atrazine kills most plants by interfering with photosynthesis, but doesn't kill maize because maize has a naturally occurring ability to detoxify it [12]. 2,4-D is a hormone mimic which promotes uncontrolled growth in broadleaf plants, but doesn't affect the hormone system of grasses, due to the natural differences between the two types of plants. There are also herbicides which affect different stages of plant growth. For example, preemergent herbicides inhibit seed germination. They won't affect plants that are already growing (e.g. your lawn, already sprouted crops) but will prevent the weed seeds that are in the ground from sprouting. -- 140.142.20.229 (talk) 20:42, 1 August 2011 (UTC)[reply]

(ec) To answer your question, the herbicide doesn't "know". Rather, many herbicides (known as "selective herbicides") are specifically engineered to be ineffective against some desirable plants, or the desirable plants are themselves engineered to be resistant to particular herbicides. We note that glyphosate, sold as "RoundUp", was conceived as a non-selective herbicide (that is, it killed all plants), but that its popularity led to the development of glyphosate-resistant plants such that it can now operate as a selective herbicide. Note also that selective herbicides require specific intentional pairings of appropriate crops and herbicides; one cannot simply use a weedkiller at will with the expectation that it won't harm everything in sight. — Lomn 15:50, 1 August 2011 (UTC)[reply]

Some herbicides are absorbed through the leaves of the plant. Those with waxy or narrow leaves absorb less of the herbicide than other plants. It happens that grass is narrow-leaved and most garden weeds are broad-leaved. Thus these herbicides kill garden weeds but not the grass, however, they also kill clover, which may-or-may-not be a weed, depending on your point of view. CS Miller (talk) 21:31, 1 August 2011 (UTC)[reply]

It's not really a difference in absorption for grasses, though waxy leaves certainly help survival. See the excellent explanation from 140.142.20.229 above. Dbfirs 22:41, 1 August 2011 (UTC)[reply]

I've removed your email address; as you can see, answers will be posted here. I found a couple of articles, one here and also one here that might be useful. --some jerk on the Internet (talk) 16:34, 1 August 2011 (UTC)[reply]

Blushing

Hello. My name is Ian, I am vacationing right now in my mother's home city of Moscow and everyone is noticeably lighter here than back in the States, hence this question popping into my head. Because of my descent (mixed Russian-Finnish), I have a very light complexion, and furthermore I blush easily and to the smallest things; even more so, I've noticed, than even other Russians. A problem I have at home in the States is that when I blush it is more noticeable to others and it is often misinterpreted in social situations by my darker American companions. I know blushing is for the most part an unconscious action but is there anything I can do to reduce the frequency or exercise some control over it? My girlfriend advised me to get a tan but that didn't go so well-- apparently I don't tan, I just burn. Thanks in advance, and a happy summer to all! --Ian — Preceding unsigned comment added by 93.94.234.152 (talk) 17:10, 1 August 2011 (UTC)[reply]

Blushing is a signal of shame, and so being ashamed of blushing will only make you blush more. So don't be ashamed of it! Be proud of your blushes! Nobody except you really cares anyway. Looie496 (talk) 17:33, 1 August 2011 (UTC)[reply]

Wikipedia has an article about Blushing that describes what is known about its causes and possible treatments. You may take comfort (?) in the fact that no animal can blush, only humans do it. Animals don't have anything to blush about. Cuddlyable3 (talk) 17:39, 1 August 2011 (UTC)[reply]

"Man is the only animal which blushes ... or needs to." - Mark Twain StuRat (talk) 17:44, 1 August 2011 (UTC) [reply]

Well, make-up would do the trick, but you might find that objectionable (perhaps you could paint your face in your favorite team's colors, at sports events). There's also the "spray on tan" chemicals, although I wouldn't recommend them, personally. StuRat (talk) 17:46, 1 August 2011 (UTC)[reply]

Certainly a light foundation, as in the sort of skin-coloured make up you apply over your whole face, would reduce how noticeable the blushes were. This is, after all, why women add blusher on top of foundation. While you might find it objectionable, if you're doing it right, with a carefully chosen 'light' foundation or tinted moisturiser, chosen to match your facial skin (not the skin on your hand) and lightly and evenly applied, will be invisible to observers and still mask the blushing (as well as giving a smoother appearance to your complexion). It would, however, be cheaper and more wholesome to come to terms with your blushing and 'own' it as a personal attribute: "I am someone who clearly signals my moods and reactions, rather than disguising them". 86.163.1.126 (talk) 19:07, 1 August 2011 (UTC)[reply]

yes but my problem is that I might blush at something random and whoever I happen to be talking to might interpret to mean I am lying or I am ashamed of something relevant to the conversation, where I'm really not, then I have to explain (and might not be believed!), which causes much more embarrassment and fuss. Thanks for the answers (although I'd prefer not to use makeup!); new ones are welcome. --Ian 93.94.234.152 (talk) 00:27, 2 August 2011 (UTC)[reply]

Trying to explain away a blush is a case of continuing to dig when you're already in a hole. Really, don't worry about it: that some people blush more than others and some (like you) blush through momentary social embarrassment is well known and understood by other socially competent people, who likely will take no notice or regard it as merely a small component of your overall personality, assuming they even notice in the first place. Those who are so socially retarded as to misinterpret or want to make something out of it - well, why should you care what they think? {The poster formerly known as 87.81.230.195} 90.197.66.109 (talk) 09:42, 2 August 2011 (UTC)[reply]

<crank theory> I feel as if the "emotion" of shame is actually just the sensation of vasoconstriction of the left middle cerebral artery, upstream of its supply to Broca's area, thus shutting down (or responding to a shutdown of?) speech. I feel as if I've been able to counter it to some extent by willing vasodilation in the same area, but I've never tried this with the equipment to test, so it might be delusion. I've seen a few people touch that region of their head when experiencing shame;

Facepalm is a stylized example (though not to the left). I wonder whether the constriction of one or several arteries in the brain could lead to a shift of blood into the external carotid artery, and from there the face.</crank theory> Wnt (talk) 17:13, 2 August 2011 (UTC)[reply]

aspirin

Is aspirin an NSAID? — Preceding unsigned comment added by 99.70.40.100 (talk) 17:28, 1 August 2011 (UTC)[reply]

Yes, as our aspirin article states in its lead. Looie496 (talk) 17:30, 1 August 2011 (UTC)[reply]

(Keep in mind the `N' stands for NON, and the abbreviation NSAID is used to describe things in terms of what they are not. To paraphrase Ulam, saying Aspirin is an NSAID is like referring to the bulk of zoology as the study of non-elephant animals.) SemanticMantis (talk) 18:17, 1 August 2011 (UTC)[reply]

That answer is good enough to not be in <small>s. 64.134.228.55 (talk) 00:56, 2 August 2011 (UTC)[reply]

I disagree. The "NSAID" designation identifies a group of compounds that share side effects, mechanisms of action, etc in a manner that is useful. To the extent that the NSAID term is useful, it is quite a bit different from referring to the bulk of zoology as the study of non-elephant animals. So, that answer does highlight a pedantic issue with the term "NSAID", but doesn't really answer the question. I think the choice of font size was appropriate. -- Scray (talk) 01:04, 2 August 2011 (UTC) [reply]

That comparison would be non-specious if it referred instead to "non-mammal animals", and if there were only three or four classes of animals. TenOfAllTrades(talk) 03:06, 2 August 2011 (UTC)[reply]

This debate is giving me a headache. ;-) AndyTheGrump (talk) 03:08, 2 August 2011 (UTC)[reply]

Take an aspirin. Ooops, no medical advice allowed. DON'T take an aspirin. Cuddlyable3 (talk) 09:45, 2 August 2011 (UTC)[reply]

That's medical advice, too! --Stephan Schulz (talk) 09:56, 2 August 2011 (UTC)[reply]

The ref.desk advises the OP not to take any advice seen on the ref.desk. Cuddlyable3 (talk) 09:27, 3 August 2011 (UTC)[reply]

Perhaps something like fish is a slightly simpler comparison. Nil Einne (talk) 01:25, 3 August 2011 (UTC)[reply]

Ok, I'll compare an aspirin to a fish then: on average, an aspirin is more likely to be soluble than a fish is ;-) AndyTheGrump (talk) 01:30, 3 August 2011 (UTC)[reply]

Instantaneous force

Hi, I'm designing a small plane; I'm working on the landing gear specifically. Suppose my plane is descending at a rate of 30 m/s at an angle of 45 degrees; What is the instantaneous force acting parallel to the ground, the moment the plane touches the ground? (Ask me if you need any extra data). 117.192.212.48 (talk) 18:00, 1 August 2011 (UTC)[reply]

I hope you're not designing a real plane, if you think that's a meaningful question. Looie496 (talk) 18:09, 1 August 2011 (UTC)[reply]

Planes don't usually land with a 45 degree glide slope but if yours does, its horizontal velocity is 30 m/s. The horizontal component of the instantaneous force on the landing wheels is whatever causes them to skid. Cuddlyable3 (talk) 18:19, 1 August 2011 (UTC)[reply]

I know; the descent angle is way too large. I mean to ask this as a simple physics question. I mentioned 45 degrees because the calculations will be easier. 117.192.212.48 (talk) 18:22, 1 August 2011 (UTC)[reply]

i want to know the instantaneous force at the time of impact. 117.192.212.48 (talk) 18:25, 1 August 2011 (UTC)[reply]

If your landing gear is rigid it will break. You cannot have instant deceleration of either the vertical or horizontal components of the plane's speed. Cuddlyable3 (talk) 18:28, 1 August 2011 (UTC)[reply]

We would need to know the mass of the plane (or the weight, from which the mass may be derived). The mass and radius of the wheels is also important, since they presumably will need to be accelerated from no rotation. I agree with the above comments, that descending at 45 degrees at 30 m/s will result in a crater. StuRat (talk) 18:41, 1 August 2011 (UTC)[reply]

Forgetting about the 45 degree angle that others pointed out isn't realistic, and assuming that the mass of the wheels are negligible compared to the mass of the plane, its clear without having to do any actual calculation that the instantaneous force acting parallel to the ground is negligible. Dauto (talk) 19:34, 1 August 2011 (UTC)[reply]

Yes, the horizontal force acts only to accelerate the wheels from initial skidding to rolling speed. Unless the wheels have a large moment of inertia, the force will be small compared with the braking force subsequently applied. To calculate the average force, you need to know the radius and moment of inertia of the wheels, the horizontal ground-speed at touchdown, and the skid time or distance. Once the wheels are up to speed, the only horizontal force is from friction in the bearings (and air resistance on the plane). Of course, if the brakes are already on as the plane touches down, rubber will be torn from the tyres by the greater friction force. Dbfirs 20:11, 1 August 2011 (UTC)[reply]

A simpler question contains the same basic issue: "Two blocks collide at 1 m/s. What is the instantaneous force between them at the moment of collision?" The answer must be that it depends on the mass of the blocks, Young's modulus, etc. The nearest parts of the blocks inevitably must match speeds first, and then transmit this force outward, in quite a complex way. The wheels of a plane add the additional variable that the force of friction is limited and they may slide over the landing strip as they first touch. Wnt (talk) 20:30, 1 August 2011 (UTC)[reply]

I think everybody missed the obvious. Assuming the ground is reasonably smooth, the force at the moment the plane touches the ground is zero. See Friction#Laws of dry friction. At the moment the plane first touches the ground, there is no applied load. The load will increase rapidly after contact, however. The speed of the plane is irrelevant.

This wouldn't happen to be a homework question, would it?--Srleffler (talk) 23:12, 1 August 2011 (UTC)[reply]

Ah, phoooey - meant to mention that when I commented but forgot. I assume that the "moment of collision" is supposed to be defined as the moment when the force is greatest, not at the moment when the objects first touch. Wnt (talk) 04:58, 3 August 2011 (UTC)[reply]

Even before the plane touches the ground a layer of air between them is being compressed. Cuddlyable3 (talk) 01:01, 2 August 2011 (UTC)[reply]

Yes, the force builds up gradually over a tiny fraction of a second as the air is compressed under the tyres, and as the weight of the plane comes to be supported by the tyres rather than by the wings. The concept of "the moment the plane touches the ground" is not clearly defined. Dbfirs 06:26, 2 August 2011 (UTC)[reply]

I'll make it simpler (No Srleffler this ain't a homework question :P ) . A body of mass 10 kg is travelling on a frictionless surface at a constant velocity of 20 m/s. Suddenly, it encounters a rough surface (say, coefficient of friction is 0.5). What would be the value of deceleration. 117.192.199.186 (talk) 06:35, 2 August 2011 (UTC)[reply]

See Friction#Coefficient of friction: "The 'coefficient of friction' (COF), also known as a 'frictional coefficient' or 'friction coefficient' and symbolized by the Greek letter µ, is a dimensionless scalar value which describes the ratio of the force of friction between two bodies and the force pressing them together". You haven't given 'the force pressing them together', so there isn't an answer. AndyTheGrump (talk) 07:13, 2 August 2011 (UTC)[reply]

Ah, but I have. The mass is 10 kg. The force pressing the surfaces together would be 10* 9.8= 98 Newton. 117.192.199.186 (talk) 07:16, 2 August 2011 (UTC)[reply]

You didn't - you are assuming a 1 G gravitational force, which you didn't state. Still, I think you have enough information to answer the question now. What is 10 * 9.8 * 0.5? This is the force. Now what is the acceleration/deceleration that results from applying this force to a 10 kg mass (actually, most of this cancels out, unless I am being even more stupid than usual)? AndyTheGrump (talk) 07:24, 2 August 2011 (UTC)[reply]

The OP has not made the original question simpler and has instead substituted an entirely different question. Cuddlyable3 (talk) 09:42, 2 August 2011 (UTC)[reply]

It is simpler, but it's also sufficiently different to call it an entirely new question. StuRat (talk) 10:34, 2 August 2011 (UTC)[reply]

The missing piece of information in this new question is the assumption that the surface is horizontal, but, taking that as given, the answer is 4.9 m/s/s for the 40.8 metres (approx) that is takes for the block to come to rest. The mass of the block is irrelevant, so exactly the same would apply to an object such as a plane, except that the undercarriage might be torn off and the sudden jerk (rate of change of acceleration) would probably cause injury to anyone not wearing a seatbelt. Dbfirs 00:40, 3 August 2011 (UTC)[reply]

So my 'physics from a bloke with a social science degree' was right: 4.9 m/s/s, or g * 0.5. It all cancels out. Actually, I'll have to ask how how you came to the conclusion that the block will ever come to rest, according to the formula you use (yes, I know, the formula is an approximation that doesn't work at the limits etc...) AndyTheGrump (talk) 00:50, 3 August 2011 (UTC)[reply]

Yes, you were correct. In the simplification where the coefficient of friction is independent of speed (a good approximation in many situations), the rate of decrease in speed is constant until the instant when the body stops. In practice, static friction tends to be marginally greater than sliding friction so in the last millisecond there may be a slight jerk and a coming to rest marginally before the calculated 40.8 m (I just used v² = 2as with "a" as you calculated - simplified from Equations of motion). In a different model where braking force is proportional to speed, as in regenerative braking, the body never actually comes to rest (in theory). Dbfirs 06:13, 3 August 2011 (UTC)[reply]

I have some Astronomy Questions:

1. Is it true the clouds of Venus are mainly composed of sulfur dioxide and sulfuric acid?

2. Is it also true Jupiter is also notable for its turbulent weather (e.g. huge storms, lightning, etc?

Thanks!

Neptunekh2 (talk) 20:27, 1 August 2011 (UTC)[reply]

I think the articles you linked cover those pretty well, and if not Atmosphere of Venus and Atmosphere of Jupiter should.

Control-F or Apple-F ("Find" in your browser) are your friends. ;) Wnt (talk) 20:34, 1 August 2011 (UTC)[reply]

How much does gravity hold the human body together?

If an astronaut floating in deep space floated into a fictional region where the force of gravity stopped working, would the tissues of his body maintain their structural integrity? I.e., is gravity at all significant in its contribution to holding the body together? 76.27.175.80 (talk) 21:49, 1 August 2011 (UTC)[reply]

In reality no. See the article Extra-vehicular activity. In fiction you can make up anything you like including turning off physical laws and having people fall to pieces. Cuddlyable3 (talk) 21:58, 1 August 2011 (UTC)[reply]

The above answer is correct, but the reasoning is flawed. There is a significant difference between free fall (which is what astronauts experience, and essentially means that the only significant force acting on a body is gravity) and an absence of the gravitational force. If there were no gravity in Earth orbit, then objects wouldn't stay in orbit—they'd fly off on straight tangents. The attractive gravitational force between an object at 350 km altitude (like the International Space Station) and the Earth is only about 10% weaker than it would be for the same object sitting on the Earth's surface. TenOfAllTrades(talk) 02:55, 2 August 2011 (UTC)[reply]

No, not significant. See Gravitational constant, where it says:

The gravitational force is extremely weak compared with other fundamental forces. For example, the gravitational force between an electron and proton 1 meter apart is approximately 10⁻⁶⁷ newtons, while the electromagnetic force between the same two particles is approximately 10⁻²⁸ newtons. Both these forces are weak when compared with the forces we are able to experience directly, but the electromagnetic force in this example is some 39 orders of magnitude (i.e. 10³⁹) greater than the force of gravity — roughly the same ratio as the mass of the Sun compared to a microgram mass.

Comet Tuttle (talk) 22:03, 1 August 2011 (UTC)[reply]

I feel the need to clarify: you asked two questions, so the answers are: Yes, the tissues would easily maintain their structural integrity, and no gravity does not have a significant contribution to holding the tissues together. Almost every other force known is more important than gravity at that scale. -RunningOnBrains^(talk) 22:06, 1 August 2011 (UTC)[reply]

When you are in free fall you are effectively NOT feeling the effect of gravity form your reference frame. For longer term effects not quite as dramatic as "falling to pieces" there's Weightlessness#Human_health_effects. Vespine (talk) 22:47, 1 August 2011 (UTC)[reply]

That's not relevant to his question. Regardless of whether you are in free fall, there is still gravitational attraction between the parts of your body. The OP was essentially asking whether this force was significant, compared to the other binding forces. The answer is "no".--Srleffler (talk) 22:58, 1 August 2011 (UTC)[reply]

Assume a spherical astronaut of mass 100kg and a density of 1000kg/m³ (ie. that of water). Those aren't far off the mass and density of a typical person. The gravitational binding energy of that astronaut would then be (by the formula in that article) about 1.4x10^-6 joules, or 1.4 microjoules. According to Orders of magnitude (energy), that's about 10 times the kinetic energy of a flying mosquito. In other words, not much. That's the energy that would be required to break your body completely apart against the force of gravity. Since we don't fly apart whenever a few mosquitos fly into us, we can conclude that there is much more holding our bodies together than gravity. --Tango (talk) 23:21, 1 August 2011 (UTC)[reply]

To clarify something even more simple: the force that holds together tissues and other molecular structures is the electromagnetic force (in the form of molecular bonds), not gravity. Gravity holds us on the Earth; it does not hold us together. --Mr.98 (talk) 00:20, 2 August 2011 (UTC)[reply]

The body is held together by material in a non-fluid state. If the body were composed entirely of gasses and liquids, it would be far more prone to changing shape and breaking up. To the extent that the body is composed of solids, even if in close combination with liquids, that is the extent to which it can hold itself together. As has been stated above, gravity plays very little role in maintaining structural stability. Bus stop (talk) 02:47, 2 August 2011 (UTC)[reply]

Geomagnetically Induced Currents

I understand that GICs are a big problem because of long stretches of cables and pipes on a global scale such as telegram/telephone cables, fiber optics, railroad tracks, and oil pipelines across oceans and continents. My question is, in order to stop such a thing why not insert a piece of plastic or some other insulator (maybe every 20 miles or whatever) so that the current won't be conducted through? This can easily be done in oil pipelines for example. So why is't it done? And also does anyone know of any incidents where such a current might have caused an ignition and hence an explosion in a pipeline? Perhaps during a solar storm? Thanks! - Looking for Wisdom and Insight! (talk) 22:34, 1 August 2011 (UTC)[reply]

You should read geomagnetically induced current and specifically GIC hazard in pipelines. Dragons flight (talk) 23:14, 1 August 2011 (UTC)[reply]

Fiber optics being non-conductive are unaffected by GICs. Cuddlyable3 (talk) 00:36, 2 August 2011 (UTC)[reply]

For those conductors which are affected, the questioner's recommendation for a series of zener diodes tied to ground is reasonable, but not optimal. 64.134.228.55 (talk) 00:52, 2 August 2011 (UTC)[reply]

I read that article but doesn't really answer any of my questions. Why isn't this optimal? Is this used in practice at all? If not then why not? - Looking for Wisdom and Insight! (talk) 18:20, 2 August 2011 (UTC)[reply]

August 2

Identifying YAG crystals

How can I tell a YAG crystal from a diamond ? I tried using a ruby for a scratch test, but couldn't get either to scratch the other. 68.79.93.3 (talk) 01:22, 2 August 2011 (UTC)[reply]

Ruby (corundum) should scratch YAG, and should be scratched by diamond. YAG can also be distinguished by its lower refractive index (1.83, versus 2.42 for diamond), higher density (4.56 g/cc, versus 3.52 for diamond), and different cut: [13], [14], [15].

You seem to be stumbling across a inordinately large number of gemstones that need to be identified. (Not a bad problem to have I suppose.) Perhaps you need to start some sort of relationship with a jeweler? APL (talk) 08:11, 2 August 2011 (UTC)[reply]

Perhaps the same gemstones, but the OP still hasn't identified whether they are diamonds because of the failure of the scratch test and a lack of trust in any external party to verify they are diamonds Nil Einne (talk) 01:48, 3 August 2011 (UTC)[reply]

subatomic particles

Where can I find a list of subatomic particles that result at different energies of proton collision? --DeeperQA (talk) 09:00, 2 August 2011 (UTC)[reply]

See list of particles. Dauto (talk) 15:45, 2 August 2011 (UTC)[reply]

subatomic shells

Is there a discussion anywhere regarding the possibility of the subatomic particles existing as clouds or in shells within the proton, like the electrons fill shells external to the atom? --DeeperQA (talk) 09:42, 2 August 2011 (UTC)[reply]

Usually the internal structure of protons is modeled by form factors. Dauto (talk) 13:48, 2 August 2011 (UTC)[reply]

~~See nuclear shell model.~~ Oops, sorry, misread. Wnt (talk) 14:33, 2 August 2011 (UTC)[reply]

The internal structure of nucleons like protons and neutrons is not well understood beyond the "quark and gluon sea" level. We don't have solid, well accepted models for the organization of quarks, with well defined geometries, the same way we do for the electron cloud. There are some models, but none has gained widespread acceptance. See Nucleon#Models. --Jayron32 16:54, 2 August 2011 (UTC)[reply]

Wow. That "chiral bag model" sounds very interesting, but the puny weapons of my mind cannot dent its neutronium armor. How does the baryon number, or quark fields, become a matter of topology and how would they cancel each other out? Wnt (talk) 17:02, 2 August 2011 (UTC)[reply]

Zinc chloride solution

What is the zinc contend in 65% zinc chloride solution — Preceding unsigned comment added by 41.29.251.155 (talk) 12:03, 2 August 2011 (UTC)[reply]

Need more info:

1) What's the solvent ?

2) Is that 65% by mass ?

3) In what form do you want the zinc content ? Also in mass ? 68.79.93.3 (talk) 13:17, 2 August 2011 (UTC)[reply]

% by volume, mass or amount? If by mass, then zinc makes up 64.85% the total zinc chloride mass, meaning that of the 65% zinc chloride solution, only 64.85% is zinc. To get the final mass percentage multiply the percentages together: 42.15%. Plasmic Physics (talk) 13:21, 2 August 2011 (UTC)[reply]

Which animal in burrow?

In rural south east England recently, I was walking along a broad strip of rough grass adjacent to a field, with some light scrub on the other side. I saw a burrow about an inch in diameter, and a circular bare patch of a few inches diameter around the burrow, which was a little off centre. Does anyone know what animal the burrow may have been made by? 2.97.215.11 (talk) 15:04, 2 August 2011 (UTC)[reply]

Do they have chipmunks in England? The article says they are native to N. America and Asia; but perhaps they are an invasive species? --Jayron32 16:48, 2 August 2011 (UTC)[reply]

I'm fairly sure (being actively interested in out-of-place animals) that chipmunks have not yet been identified as an invasive species in SE England, though there's no telling if some idiot has released one or more into the wild very recently. However, there are other more likely candidates.

My immediate thought was a weasel, whose burrow entrances, as you will see from that article, are typically this size. Other possibilities are a wood mouse or yellow-necked mouse (aka field mouse), a vole (in the European, not North American, sense), or even a solitary bee or solitary wasp (I'm assuming if it had been the entrance to a communal bee or wasp nest, you'd have seen some of its denizens).

The ever reliable Sun says that chipmunks are already here[16]. Alansplodge (talk) 22:23, 2 August 2011 (UTC)[reply]

Doh! How could I have missed an announcement in such a scholarly and reputable scientific journal :-) ? {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 22:32, 2 August 2011 (UTC)[reply]

[Later] Ok, a perhaps more reliable report from a Dr Toni Bunnell of the University of Hull via The Independent, though I note that Dr Bunnell is also a practitioner of Reiki and has investigated healing by laying-on of hands, which suggests a less-than-complete focus on wildlife studies. {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 23:04, 2 August 2011 (UTC)[reply]

More knowledgeable UK naturalists may have further suggestions, but probably more clues are needed for a definitive identification - any chance of making some follow-up observations? {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 19:57, 2 August 2011 (UTC)[reply]

What follow-up observations would you like? 2.97.215.11 (talk) 22:57, 2 August 2011 (UTC)[reply]

Finding droppings or other perhaps-related debris in the burrow's vicinity; traces of fur around or near its edges; prints in the earth and trackways in vegetation; observations to eliminate insect candidates (taking due regard to appropriate times of year)? You might also consult staff at a nearby town museum for local information and advice about local wildlife, or seek out local naturalist societies: in the latter cases, photographs would be useful, as they can show relevant details of micro-topography that we (given the wide possibilities) have not thought to ask and you might not have noticed or be easily able to describe, but that would be meaningful to experts (of which, let me stress, I am not one). {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 23:19, 2 August 2011 (UTC)[reply]

Tips to identify a Bird of prey in southern england?

In rural south-east england I have had brief glimses of large brown birds that I thought could be birds of prey. One was sitting on a fence post as I sped past, another passed me skimming over the heathland vegetation as if hunting.

For future reference are there any ways of identifying or making a good guess about which species they are, for when I have another brief glimse of similar birds in the future? 2.97.215.11 (talk) 15:12, 2 August 2011 (UTC)[reply]

A Red Kite perhaps? They are on the increase in southern England. Try the RSPB bird identifier page.--Shantavira|^{feed me} 15:16, 2 August 2011 (UTC)[reply]

The best guess for the first one is buzzard. But I'm more interested in being able to quickly identify birds of prey that I see in the future. 2.97.215.11 (talk) 15:39, 2 August 2011 (UTC)[reply]

After looking through the Wikipedia articles, am I correct in thinking that the birds of prey I am likely to see in south eastern Britain would be, using their common local names: falcons, kestrels, harriers, goshawks, buzzards, and sparrowhawks? Owls and the extremely rare eagles would be easy to differentiate. 2.97.215.11 (talk) 15:29, 2 August 2011 (UTC)[reply]

Buzzards are a lot bigger than one might think, and usually seen high overhead rather than flying around or perching low down. Really, just as some young prince was once told "there is no royal road to mathematics," for bird identification there is really no substitute for obtaining and studying a good field guide (those published by Collins are held in high regard, but there are others), watching appropriate nature programmes, and above all spending time outside (with the aforesaid guide) actually watching birds (or whatever - the same applies to butterflies, dragonflies, etc). {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 20:04, 2 August 2011 (UTC)[reply]

August 3

Snowing right now

Where in the world is it snowing right now? Barbaricslav (talk) 01:35, 3 August 2011 (UTC)[reply]

It's winter in the southern hemisphere so it may well be snowing in the ski resorts in the mountains of Chile, for example, or perhaps in the Snowy Mountains of Australia. Antarctica is likely to have a storm or two. I have known it to snow in some of the northern hemisphere mountains in August -specifically in the Canadian Rockies. Bielle (talk) 01:58, 3 August 2011 (UTC)[reply]

Perhaps also Alert, Nunavut:

"Alert has a polar climate. The weather is very cold, and there is snow cover for 10 months of the year on average. The warmest month, July, has an average temperature of 3.3 °C (37.9 °F). Alert is also very dry, averaging only 153.8 mm (6.06 in) of precipitation per year. Most of the precipitation occurs during the months of July, August and September, mostly in the form of snow. On average there is 16.1 mm (0.63 in) of rain which occurs between June and September. Alert sees very little snowfall during the rest of the year. September is usually the month with the heaviest snowfall. February is the coldest month of the year. Snowfall can occur during any month of the year, although there might be about 20 frost free days in an average summer.[7]" Count Iblis (talk) 02:09, 3 August 2011 (UTC)[reply]

New Zealand's South Island received a heavy snow dump a week or two ago. Plasmic Physics (talk) 04:36, 3 August 2011 (UTC)[reply]

It seems that there is no current snowfall in southern Chile, Australia or New Zealand. According to BBC News there should be light snowfall in Punta Arenas on Friday. But Weather Underground reports ongoing snowfall in several locations on Antarctica: Amundsen-Scott, Base Orcadas, Dumont d'Urville Station, and Vostok Station. 130.188.8.11 (talk) 09:30, 3 August 2011 (UTC)[reply]

hammerhead sharks

can hammerhead bite head on or do they have to turn there heads to one side to stike — Preceding unsigned comment added by Jteuscher (talk • contribs) 01:42, 3 August 2011 (UTC)[reply]

Our Hammerhead shark article (which could do with a few more sources I think) suggests that hammerheads are mostly bottom feeders, and states that they may sometimes pin down rays with the 'hammer' to eat them. I'm not entirely convinced by this, but they certainly look better adapted to taking bites out of things underneath than in front. Given that some species have been known to attack humans though, I think it is safe to assume that they are flexible enough to attack in other ways. AndyTheGrump (talk) 02:10, 3 August 2011 (UTC)[reply]

For a specific example, see also Great_hammerhead#Feeding mentioning examples where the shark "disables" the prey (stingray) with its first bite, then pins it with its head, and finally "takes the ray in its jaws head-first". This section does cite five references. ---Sluzzelin talk 02:17, 3 August 2011 (UTC)[reply]

Torque and power

why the maximum power and torque of an engine specified at different RPM's ?

Torque is essentially force, power is essentially force multiplied by velocity. They are different things. You can have a large torque when the engine is not moving, but the power in that case is zero. Looie496 (talk) 02:44, 3 August 2011 (UTC)[reply]

Effect of star Jupiter on Earth

In his series of books beginning with "2001 A Space Odyssey", Arthur Clarke has a race of super advanced aliens cause Jupiter to turn into a star. If such were to happen, would we be likely to see the new Jupiter with the naked eye, and would the light be bright enough to disrupt life on Earth? — Preceding unsigned comment added by GuadalupePeak (talk • contribs) 02:39, 3 August 2011 (UTC)[reply]

I guess you didn't read the book. (2010: Odyssey Two, that is.) In the book, he has the aliens turn it into a very dim star, just bright enough to warm up Uupiter's moon Europa. Looie496 (talk) 02:50, 3 August 2011 (UTC)[reply]

As far as the visibility is concerned, you can already spot Jupiter with the naked eye during daytime, see here. If Jupiter were to turn into a star, it would be much easier to spot, of course. Count Iblis (talk) 02:56, 3 August 2011 (UTC)[reply]

Jupiter's Moons Ganymede and Callisto can also be seen using the naked eye, see here. Count Iblis (talk) 03:13, 3 August 2011 (UTC)[reply]

I think we used to have a page on the Lucifer project which is a conspiracy theory that NASA (or the illuminati or NWO or whatever malevolent power you want to believe in) were going to try to ignite Jupiter.. Looks like the page is gone, but you can still find info about it if you google the term. Vespine (talk) 03:51, 3 August 2011 (UTC)[reply]

I think the main concern with this would be whether the new star would be bright enough to damage the retina, like an arc welder. Jupiter is about 1/10 the radius of the Sun, thus 1/100 the area - but it's also 4-6 times further away, making it 1/16 to 1/36 smaller in apparent size than that. But if it had the same color temperature as the sun, that 1/1600 bit of area would be just as bright as the sun itself. In total eclipses even fairly small areas of exposed sun are dangerous - actually much more dangerous than looking at the sun because the iris opens up, not being designed for extreme brightness in an overall dark scene. Especially at night this would be dangerous. Humans might learn to avoid looking at it before going blind (though I think something like that would be harder to learn than you'd think) but certainly nothing else would. These risks would be much reduced if it turned out to be a brown dwarf or something, much cooler on its exposed surface. Wnt (talk) 04:46, 3 August 2011 (UTC)[reply]

It's a pretty pointless question, it's like asking: if Jupiter gives off light, how much light would it give. The answer is pretty much up to you. Alternatively, if this lead sinker floats in water, how dense is it. Lead doesn't float in water, so the answer is: it is as dense as you want it to be, although less than water. So, if Jupiter was a star, it is as bright as you want it to b, as long as it is brighter than it's natural reflection. Plasmic Physics (talk) 05:26, 3 August 2011 (UTC)[reply]

Not to get too picky, but Jupiter is technically "brighter" than its natural reflection, it emits more energy than it gets from the sun, per the Kelvin–Helmholtz mechanism. What makes Jupiter not a star is that it doesn't undergo nuclear fusion; according to our article on Jupiter, it would need to be 75 times more massive in order to support nuclear fusion. In order to make it a star, Arthur C. Clarke had to invoke his own third law by introducing a little bit of "magic" in the form of the monolith. As Plasmic Physics notes, there is no conceivable way Jupiter could actually be a star, so discussing how it would become one is a purely fictional venture. --Jayron32 05:44, 3 August 2011 (UTC)[reply]

Beyond the standard model and low temperature physics experiments

Hi, is it possible that one could find standard model discrepancies at very low temperatures (like someday 10^{-50} kelvin?) as well as at the very high energies in particle accelarators? Thanks, Rich Peterson24.7.28.186 (talk) 03:54, 3 August 2011 (UTC)[reply]

Like maybe dark energy doesn't "work" except at low temps?24.7.28.186 (talk) 03:56, 3 August 2011 (UTC)[reply]

- The reason why high temperature testing of the Standard Model is done in the first place is generally to try to understand what the universe was like arbitrarily close to the Big Bang. The deal with low-temperature physics is, we have lots of examples around us (i.e. most of the universe is pretty cold) and most of the really exotic stuff happens when particles are energized enough to start to break down. You can get essentially infinitely hot (pre-empting the objections: yeah, I know there are limits here too, but not the same way as at the other end), but you've got a limit to how cold you can get. We've gotten very close to that cold limit, so we've got a pretty good handle on what happens there, but we've come nowhere near recreating the conditions at Big Bang time, which is why that is where the bulk of research is driven. --Jayron32 04:22, 3 August 2011 (UTC)[reply]

I feel like the "limit to how cold you can get" is illusion. The universe goes through different regimes of physics according to the log of its age, and the log of its temperature. There may be no limit to how old or how low temperature it can get, and I'm also suspicious that over very long time scales at very low temperatures and very low masses, some new physics could emerge when ours is too hot to be of much importance, just as has happened so many times before in history. Wnt (talk) 04:56, 3 August 2011 (UTC)[reply]

Could you please explain to me how one can go a slower speed than "stopped". Because I am not smart enough to understand how one may get colder than absolute zero. --Jayron32 05:35, 3 August 2011 (UTC)[reply]

Seconded. --Stephan Schulz (talk) 07:07, 3 August 2011 (UTC)[reply]

As I said, a logarithmic scale. People have proposed all sorts of bizarre physics for the first second after the Big Bang. What happens when you look at the interactions of matter at 10^-30 Kelvin over a period of 10^50 years? Maybe we're living now in another one of those periods of strange high-energy physics in the "moment" after the Big Bang, from that perspective? In other words - suppose there's proton decay. Suppose there's electron decay.^[17] Suppose you have a sea of neutrinos and nothing else, whizzing around over unimaginable time spans until they somehow come to rest with respect to one another. Do they start forming chemical-ish interactions? (No, I don't know, but I think it's a fair question) Wnt (talk) 08:09, 3 August 2011 (UTC)[reply]

Getting sulfur from Gypsum.

Gypsum is Calcium Sulfate and has the formula CaSO4·2H2O, which seems to indicate it has a lot of sulfur in it. Let's say I wanted to get pure sulfur out of gypsum, what would I need to do? — Preceding unsigned comment added by 24.72.218.111 (talk) 06:41, 3 August 2011 (UTC)[reply]

You could use a strong reducing agent to obtain the sulfur - though the reducing agent would be worth more than the sulfur. Or you could use microorganisms that extract oxygen from the gypsum under anaerobic conditions - I'm not sure if this has been done on a large scale for synthetic purposes, but it happens accidentally with drywall, which can thus emit hydrogen sulfide which can more readily be used to make elemental sulfur.^[18] Google knows no hits for "fermenting gypsum" - somebody ought to fix that. ;) Wnt (talk) 08:04, 3 August 2011 (UTC)[reply]

To what temperature in Kelvin or degrees Celsius does Gypsium have to be heated to decompose it into vitriolic aire and calx? Is it easier to reduce vitriolic aire to sulfur? Plasmic Physics (talk) 08:44, 3 August 2011 (UTC)[reply]

Evolution

Apart from Index to Creationist Claims, what other major, long, detailed or comprehensive list of arguments defending evolution or responses to arguments against evolution are there on Internet websites? Is that list the only such list in talk.origins?

I am asking this because there is a list of responses to Index to Creationists claims in Creationwiki. — Preceding unsigned comment added by 110.174.63.234 (talk) 08:34, 3 August 2011 (UTC)[reply]