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January 5

I can directly control blood flow throughout my body

Is anyone else capable of doing this? For example, I can get an erection at will (without physical or mental stimulation) [this is not a joke I assure you]. I can also increase blood flow to my head, although the last time I tried (many years ago) it immediately triggered emotional problems. I can also increase blood flow to my eyes. Anyone familiar with this condition? I guess it's never too late to ask. Thanks.Phenylalanine (talk) 01:06, 5 January 2014 (UTC)[reply]

Biofeedback.
In the case of a penis the evidence is obvious, but I'm curious as to how you know that there is an increase in blood flow in your head or eyes. Are you actually measuring it with some instrument? Mitch Ames (talk) 01:20, 5 January 2014 (UTC)[reply]
Thanks for the link. It says that you can control your heart beat and blood pressure, etc. through biofeedback, but, my experience is more specific, I feel as though I can, simply by willing it, get my blood flowing to specific parts of my body (either my head, my eyes or my penis). No, I am not measuring it with any instrument. I simply feel the blood rushing to and pounding in my head. As for the eyes, I feel pressure in them and sometimes the eyes get red.Phenylalanine (talk) 14:17, 5 January 2014 (UTC)[reply]
I know I've fooled with circulation a bit - it's possible to view the increase directly as a visible redness around a sore you're trying to give more circulation to... on the downside, fooling around with alterations in brain circulation trying to (allegedly) improve/redirect cognitive power, I once managed to give myself a painless ocular migraine (which I never had before or since). Frankly, though, I suspect (based on scanty tests) at least half of all the effects are based on a simple voluntary increase in blood pressure rather than the targeted effect that one is looking for, and I think that a skeptical referee should demand evidence that there is a BP-independent effect. Your description of erection somehow reminds me of Taoist sexual practices (though it's not really the same thing). It also reminds me of one of the practices of the Kama Sutra, in which the man and woman were to remain motionless yet consummate. Wnt (talk) 05:11, 5 January 2014 (UTC)[reply]
Thanks Wnt.Phenylalanine (talk) 14:17, 5 January 2014 (UTC)[reply]
How can you will something without mentally stimulating it? Anyway, a man named Haridas may have gotten the same magic boner you do. Other fakirs (not necessarily fakers) have claimed similar things. InedibleHulk (talk) 05:35, 5 January 2014 (UTC)[reply]
On whom (Sadhu Haridas) we have an article, incidentally. Tevildo (talk) 11:50, 5 January 2014 (UTC)[reply]
Thanks for the link. What I mean is that I will it, but I don't think of anything in particular (like say a nude woman).Phenylalanine (talk) 14:17, 5 January 2014 (UTC)[reply]
Perhaps you're simply sexually attracted to the thought of yourself getting hard. Some sort of subconscious narcissism. Don't mean that as an insult, just something to consider. InedibleHulk (talk) 14:55, 5 January 2014 (UTC)[reply]
Also, you may be confusing blood flow with air pressure, if your eye method involves blowing with your blowholes closed. I used to blow various beverages out of mine that way to amuse my classmates. As I got older, it started to hurt too much and they moved on. Definitely feels like blood in there. InedibleHulk (talk) 05:43, 5 January 2014 (UTC)[reply]
Yikes, I didn't know that was possible. That's not the way it occurs in my case.Phenylalanine (talk) 14:17, 5 January 2014 (UTC)[reply]
It didn't exactly squirt out like a horned lizard (which certainly do use blood pressure). Just leaked. More just odd than yikes. InedibleHulk (talk) 14:55, 5 January 2014 (UTC)[reply]
I've found remembering a past mental state can do a few things, the most useful for me is I used to have hiccups sometimes which went on for a while but now I can stop them immediately by thinking of the feeling when they went away. Dmcq (talk) 11:28, 5 January 2014 (UTC)[reply]
I wish I could do that.Phenylalanine (talk) 14:17, 5 January 2014 (UTC)[reply]
Thinking about it, setting a mental state is probably the sort of thing that biofeedback is training people to do so there's good chance there may be a way to do it with that somehow. Dmcq (talk) 17:38, 5 January 2014 (UTC)[reply]
Here are a few other animals who seem to know your trick. Maybe you'll find some insight through them. InedibleHulk (talk) 15:00, 5 January 2014 (UTC)[reply]
Cool, thanks.Phenylalanine (talk) 17:18, 5 January 2014 (UTC)[reply]
  • Here's a weird hypothesis for your consideration (I doubt there's any data about it though! But I'm curious what you'd think of the idea): I suspect that the "emotion" of embarrassment/shame/shyness is purely the physical sensation of the constriction of blood vessels in the general region of Broca's area. I've noticed that for purposes of "GOTV" type activity that it seems to be possible to oppose this feeling directly by focusing on increasing the blood flow rather than decreasing it. I also suspect that the facepalm is a direct (though for most 'unconscious') response to this sensation... Wnt (talk) 16:21, 5 January 2014 (UTC)[reply]
Fascinating. Looks like you've been experimenting a lot with controlling your blood flow. In my case, the results have not been good. There was a time when I couldn't control the blood flow in my eyes and was feeling intense and uncontrollable waves of pressure in my eyeballs. Now, it mostly doesn't happen, although I can trigger it at will. Phenylalanine (talk) 17:18, 5 January 2014 (UTC)[reply]
Actually anyone can control the blood flow in their body, through techniques such as biofeedback (which I see you've dismissed), autogenic training and self-hypnotism. I don't think you're particularly special, just someone who's learnt how to do something on their own that other people can do too. --TammyMoet (talk) 16:22, 5 January 2014 (UTC)[reply]
Initially, I thought maybe it was some sort of Psi effect...Phenylalanine (talk) 17:18, 5 January 2014 (UTC)[reply]
I don't think he really dismissed biofeedback, but it's good to point out that it goes beyond whole-body parameters - if it in fact works on migraine (and there's a lot of people saying it does), that is very close to proof that it can affect specific blood flow patterns in the brain. For real proof I'd want to see fMRI (PMID 17508158) or PETT data, or some kind of proof of actual blood flow change - unfortunately I don't readily have access now to the PMID above - someone let us know if it's good? Wnt (talk) 16:41, 5 January 2014 (UTC)[reply]
Yes, the PMID is accessible. Thanks.
erm, whoops, I meant the article pointed to by the PMID, not just the abstract. Wnt (talk) 18:53, 5 January 2014 (UTC)[reply]
No, I do not have access to the full article. Phenylalanine (talk) 19:56, 5 January 2014 (UTC)[reply]
I think the broader context of this is that there is some reason to be skeptical about the absoluteness of the distinction between voluntary muscle and involuntary muscle. The distribution of blood around the body is governed by smooth muscle containing sphincters, much like those of the iris, pylorus, or inner anus. Now, subjectively, the action of any muscle seems to be a balance between "conscious" and "unconscious" factors. For example, if you look at something out of focus, you can open up your iris a little bit with little effort, but then the increased light makes you involuntarily close it back to its normal value. If you try to lift something really heavy, sooner or later you can't stand the strain and give up or drop it. It seems like the difference is more quantitative than qualitative, and so there ought to be some ability to control virtually anything connected to a nerve - why not? To children it seems all but impossible to control the anus; to adults it may seem next to impossible to open the pylorus and let food out of the stomach to avoid becoming dependent on a "little purple pill" - is there really a difference in the difficulty of these two things? I don't know. Wnt (talk) 22:01, 8 January 2014 (UTC)[reply]

Can fusion ever be a real, competitive power source?

I was reading another one of these articles - I feel like it could have been written in the 50s - about how with three different kinds of very expensive technical advances, and a few years, and some billions of dollars, nuclear fusion is finally going to reach the point where it is close enough to producing the power put into it that it will look encouraging.

I understand, of course, that from the beginning fusion has seemed tantalizingly possible due to the fusion bomb. Yet reading that article, I'm surprised to see it sounds like in any fusion bomb, most of the energy comes from fissioning of plain old uranium, with fusion just forming a good source of neutrons. And while of course fusion works in the Sun, it produces about the same energy per mass as a compost heap, AFAIR. None of this stuff really makes me think this reaction has a desire to shower us with infinite power if we just but understood it.

Now what I wonder is, what happens once it is capable of powering itself with a little left over? There are some things I wonder that are already mentioned in the ITER article, like, if fusion is actually carried out commercially, don't all the neutrons it produces make everything around it into radioactive waste, so that it's practically like using fission power? But there's one thing I still have to ask:

Has anyone, ever, seen a way that a nuclear fusion plant can ever, even in theory, actually produce as many total watt-hours PER DOLLAR INVESTED as solar panels, wind turbines, or geothermal? Is there any scenario where it really can stand in an open free market as the best source of power? Wnt (talk) 19:04, 5 January 2014 (UTC)[reply]

You're asking for predictions about the economics of future technologies. According to a sentence at the top of this page, we don't answer requests for predictions. Red Act (talk) 19:23, 5 January 2014 (UTC)[reply]
To be technical, I asked "has anyone ever seen...?" - I'm just looking for a sense of what a successful fusion plant is supposed to look like. I can't mentally picture giant lasers and hot plasma around something the size of a pencil eraser working out to a low capital investment. Wnt (talk) 23:09, 5 January 2014 (UTC)[reply]
Not something I know a lot about, but have you read the Fusion power article? - that seems to answer your question about nuclear waste. The other thing that strikes me is - would governments and researchers around the world be investing millions (billions?) of dollars in fusion research if there wasn't a high probability that the technology would be viable as a way of producing energy in the forseeable future? Richerman (talk) 19:32, 5 January 2014 (UTC)[reply]
Ah, but they're not, this is the point. The _total_ budget for ITER, split over the entire EU and six other countries, is €15 billion. The budget for HS2, in comparison, is £43 billion (€52 billion), and the actual cost is estimated at about twice that - which is just for one EU nation. If the governments of the world were serious about fusion, they'd be putting a damn sight more money into it than they are at present. Tevildo (talk) 19:52, 5 January 2014 (UTC)[reply]
Ah, the short-termism encouraged by our political system! Of course the British government are hiding their heads in the sand about our impending energy crisis anyway. However, after a little more reading I think this reference from the Fusion power article answers the question of possible the returns on the investment. Richerman (talk) 21:38, 5 January 2014 (UTC)[reply]
Thanks for pointing out this reference. But to be clear, what would a fusion plant generating the required 1 GW to be competitive look like? Does that mean all this radiation has to come out from one moderately small, incredibly densely packed area? Can any material survive in there? Wnt (talk) 23:09, 5 January 2014 (UTC)[reply]
The reaction itself would happen either suspended in vacuum by electromagnetic fields (e.g. ITER) or using an inexpensive physical support that is destroyed and replaced after each burst of energy (e.g. inertial confinement fusion, which can use something akin to fishing wire to anchor their target). The spot where the fusion reaction itself occurs is a very confined region that pretty much gets blown to hell, but the energy output is meant to be captured at the outer walls of a chamber which is much larger than the reaction region. For example, if a fusion reaction generates 1 GW, you might capture that energy over a sphere 20 m across, yielding 200 kW / m^2. That's a large thermal flux, but materials exists that can sustain that. (Though at present the best materials for lining fusion reactors due tend to wear out due to radiation exposure much faster than is likely to be economically reasonable for a hypothetical commercial reactor). Dragons flight (talk) 00:08, 6 January 2014 (UTC)[reply]
Lots of great answers here on all sides. So to be clear - tell me if I have this right - if I were to picture a scene set in a future fusion plant, they'd have a spherical chamber 10 m in radius (perhaps 6 industrial stories tall) with extremely thick layers of shielding around it (I'm not sure what would most resist being turned radioactive by the neutrons). I don't know how magnetic confinement could affect something at the center of a big empty sphere, but I can suppose every second a fuel pellet would drop from a long tube directly above the center, lasers would lock onto it, and they'd blow it away with ... unbelievable amounts of energy, but less than it is about to produce. It would then explode with the force of a ten-gallon can of gasoline well mixed with air, but without producing very much vapor relatively speaking so it would not produce as strong a shaking as a gasoline bomb; it wouldn't really rumble like a giant car engine from just the pellet's worth of gas and radiation pressure alone. To the point of view of the terrorist villain who we suppose has just run down the zigzag tunnel to the main access door, the light coming through the thick observation window in the access door is incredibly bright - not 1000 times the brightness of the sun on average but concentrated into a single instant, since most would be heat or ionizing radiation, but not that large a multiple less than that; it would I suppose very badly sunburn skin in a single flash? though with a delay for the person to realize it. He presses the button to extend the catwalk and it manages to stay intact despite the repeated blinding flashes of light just above it. After the next flash, he races forward with the Bomb held high, shouting his holy slogan; a flash takes him midway, staggering him and shattering every genome in his body, but he continues to move forward (?) blindly on the catwalk, guided by faith or luck, enduring another flash four times closer and stronger than the first, lurching desperately toward his goal - when, of course, I suppose the hero of the piece rushes in to open fire on him just before his crude sphere of uranium comes close enough to the central point, while his girlfriend at last successfully hacks the computer to prevent the last fateful pellet from dropping and exploding close enough to set off the bomb, incidentally saving the hero's life ... Wnt (talk) 04:29, 6 January 2014 (UTC)[reply]
Yes, that's a plausible image of what a laser induced inertial confinement fusion reactor could look like, though I doubt they would have windows. (Other types of reactors could have different layouts. For example, machines like ITER are toroidal.) The terrorist is likely to be disappointed though. Any reasonable engineer would make it impossible to enter while the machine was running. Further, for practical reasons the reaction chamber would almost certainly be maintained at a significantly reduced air pressure. That type of fusion machine doesn't require the strong vacuum of a tokomak, but a reduced atmosphere does improve laser function. As a result, breaching the door would flood the room with air with the likely side effect of shutting down the machine anyway. Beyond that the walls and floors are likely to be heated to the point of glowing and the radiant heat would be roasting for anyone who tried to enter. Nor would a pellet detonation be remotely survivable at close range, but then I guess having the terrorist's flesh boil and explode into vapor isn't a good movie ending. Dragons flight (talk) 19:00, 6 January 2014 (UTC)[reply]
Thanks! For the door and auto shutdown I can just say "hacking" and be done. You're right that the walls should be glowing cherry red with all that energy; while they could be cooled the higher temperature should be better for Carnot cycle extraction. The weak atmosphere is actually a plus for the scenario, because I can say when he breaches the chamber it is momentarily flooded with cold air; still, he's going to need one of those snazzy reflective fire suits from some old James Bond movie. Which brings us to the real sticky point, the pellet explosion - you are perfectly right that all the energy of a big can of gasoline is going to be radiated out and if you're fifteen feet away you're picking up, I dunno, 10 square feet out of 800 or about the same energy as half a liter of gasoline being sprayed on your flesh and set on fire. Ouch. I suppose the suit might reflect some, but I really don't have a good mental image of what a very abrupt lethal irradiation is like. Also, I suppose 1/80 GJ of energy carries 1/7 micrograms of mass, moving at 3x10^8 m/s is like nearly 50 grams hitting you at 1 m/s .. that's still less than a tenth of the power of being shot with a .22 bullet, still, I suppose you'd feel the force, while getting fried. Wnt (talk) 00:51, 7 January 2014 (UTC)[reply]
Power generation isn't all about $/kW - a lot of the problem is that you need energy on demand. Solar power only works in the day - and how much it makes depends on the weather. Windmills are also patchy producers of energy. Geothermal, tidal and hydo are all better - but they are not widely available. The joy of oil/coal/gas and nuclear energy is that you can throw a switch and you have power at any time in just a matter of minutes. When everyone wants to cook supper in the gap between two good TV shows, they need energy **NOW** and renewable sources are very poor at delivering that. There have been efforts to build large-scale energy storage systems that could store energy on sunny/windy days and give it back on dark/calm days - but they are expensive, inefficient and difficult to deal with.
Fusion power is a long-shot...but it's all we've got. Fission also works - but nobody really likes it and it has the capability of making a terrible mess - also, we'll eventually run out of fissionable materials. Fossil fuels quite clearly aren't usable for much longer. But there is enough deuterium in the world's oceans to provide humanity with power for millions of years...and more of the stuff available from the Moon and elsewhere in the solar system.
I disagree about the amount of energy that fusion could theoretically generate being really low - I don't know where you got those numbers - E=Mc2 applies here. Experimental fusion plants aren't producing much excess energy - but that's because they're experimental.
The reason fusion research isn't well funded is a matter of politics - not science.
SteveBaker (talk) 22:47, 5 January 2014 (UTC)[reply]
"E=Mc2" applies... sure, but in this case, if "E" is the energy released by fusion, then "M" (the mass) in the equation is the mass defect of the fusion reaction, not the total mass of the fuel. Nimur (talk) 00:02, 6 January 2014 (UTC)[reply]
This is why I prefer a handy matter-antimatter reactor. StuRat (talk) 00:13, 6 January 2014 (UTC) [reply]
Whether it has to work is sort of irrelevant - question is, can it? Besides, I would think that geothermal heating could supply all our needs reliably; also, storage tech is vastly improving, so it's surely not the only option. Wnt (talk) 23:09, 5 January 2014 (UTC)[reply]
Well when you look at the options none are very high on assurance grounds. We need to put money into a whole host of options but we can't put all our money in, we have to live today. The best bet is to put in money so the research is done efficiently rather than trying to do a moon shot sort of business. Other things competing are for instance having DC lines going from temperate zones to desert areas with solar energy and around the world - which would be a huge engineering effort and beset by political problems, carbon capture and storage to try and gain a bit back from global warming - not exactly hopeful but has to be tried, fast breeder reactors - but who's keen on that?, or power from waves - this has a similar long and not very successful history. Fusion power has got some promise and even if it takes another fifty years I certainly believe it is a worthwhile project. Dmcq (talk) 23:28, 5 January 2014 (UTC)[reply]
Here is an example of a study trying to make educated guesses about the economics of fusion power. In their model, commercial fusion energy first becomes available after 2040 with a cost per kWh about 3 to 4 times higher than competitive fossil fuel technology (driven by large upfront facility costs). By 2100 they imagine fusion costs come down so that they are only about 1.5 times the cost of fossil fuel. In other words, they are assuming that through the 21st century, fusion energy would require subsidies in order to competitive with fossil fuels (or equivalently, fossil fuels would have to be penalized based on carbon emissions). They also assume that fusion is more expensive than solar, wind, and traditional nuclear options during the entire 21st century, though the cost penalty comes down towards the end. Of course, not all choices about energy mix are driven by electricity cost. Factors such as pollution, carbon emissions, constancy of power supply, and incremental deployment costs are also important. Over the long-term, fusion seems a relatively safe and sustainable form of baseload power, which makes its development interesting, but it isn't magic and it seems unlikely that fusion will be so cheap at any point during this century that people would abandon alternatives forms of power for purely economic reasons. Dragons flight (talk) 23:37, 5 January 2014 (UTC)[reply]
I'll throw in another wrench to the works. Fusion research has two epicenters in the United States: at Sandia National Laboratories in New Mexico, and at the National Ignition Facility in Livermore, California, which is just a twelve-minute flight from my home.
Both of those facilities are funded by the Department of Energy. Neither is an ordinary National Laboratory. Both facilities are, very clearly and openly and publicly, what the Department of Energy calls nuclear weapons laboratories. For example, the top line of the Mission Statement at Sandia's website says:
And the same, at Livermore's NIF website:
So, when Wnt reads and links a fantastic piece of science published in the journal Nature (or rather, on its website Nature News), he may be missing a little bit of context (perhaps he's not reading between the lines). That experiment for fusion-power is part of a weapons laboratory. Research physicists do not work at Sandia because they are developing the next generation of civil energy supplies. There are dozens of other facilities and national laboratories funded by the Department of Energy where research physicists study the fundamental science to ensure a reliable civil energy supply. At Sandia, the physics is all about nuclear weapons.
Since there are many many international treaties that prevent the United States from pursuing active programs that verify weapons integrity by detonation-style nuclear testing, there is a need to find alternative methods to verify that our warheads are still functional. The best way to verify that they still work is to blow one up every now and then. But that's no longer allowed: there have been a series of treaties, including the START II agreement.
Because our nuclear stockpile still exists, and it is populated mostly by thermonuclear weapons that were built in the late 1980s, and because international agreements prevent the Department of Energy from detonating any weapons to test them, labs like Sandia and the NIF have no choice but to simulate weapons.
So when you see an enthusiastic physics publication proclaiming the future of fusion energy, and you see that it came from a weapons lab, the message you're really supposed to take away is this: the United States still has thermonuclear weapons capabilities, and it's honoring its international commitments by not blowing any up, but this is a pleasant reminder that the capability still exists.
Steve Baker probably nailed it when he said that this publication - this entire area of research - is "a matter of politics - not science."
Nimur (talk) 00:27, 6 January 2014 (UTC)[reply]
That was my feeling going in, and I'm still prone to agree, but still the sources above showing a steadily increasing triple product and arguing for eventual possible viability carry some weight. Plus I have to wonder whether reactions in fusion reactors without uranium present really give all that much useful information about fusion bombs, and also, what does the EU get out of it? There is, after all, another conspiratorial explanation available which is just that some people are going to lobby hard to keep their jobs. But I'm still skeptical of fusion's viability, because those arguing for its eventual economic role still use an optimistic model and seem to treat it as a clean energy source, despite the problem of induced radioactivity, which might make their numbers inapplicable. Wnt (talk) 19:06, 6 January 2014 (UTC)[reply]
There are only 36 isotopes with half-lives between 1 year and 1 million years. Isotopes that have longer or shorter half-lives than that don't tend to be a long-term waste problem because they are either so unstable that they burn off quickly, or so stable that they aren't very dangerous. Of those 36, 15 are at least as heavy as uranium, so you can avoid those simply by not having any really heavy elements in your reactor design. After that you go down the list and start figuring out what materials you have avoid in order to minimize the production of problematic isotopes. One of the things you quickly figure out is that nickel is not a good idea, and likewise for molybdenum, niobium, copper, and nitrogen. Thankfully iron is okay, so we can use steel, but you end up looking at steels with unusual compositions using elements such as chromium, manganese, titanium, tungsten, and vanadium, instead of alloys normally involving nickel / molybdenum. Most of the radioactive danger from fission plants comes from the fuel, and that's the waste people talk about generally. However, with fission you also have induced radioactivity of various structural elements, that you want to keep to a minimum. For the most part, we already know how to do this so that the non-fuel elements are safe enough to qualify as low or medium level radioactive waste, which are suitable for shallow burial in existing land fills that are specially licensed for the disposal of such wastes. Obviously avoiding sources of long-lived induced radioactivity is a major concern, but it is likely to be a surmountable problem. You'll still have a variety of low-level radioactive wastes to worry about, but well-designed fusion plants should be able to avoid creating the highly dangerous kinds of wastes that are associated with fission products. It is also worth noting that fusion plants don't have a failure mode that can lead to an uncontrolled meltdown, which greatly reduces the risk of uncontrolled radiation releases. Dragons flight (talk) 20:17, 6 January 2014 (UTC)[reply]


January 6

Soft tubing materials?

I figure I can shoe-horn this question into the science section as a question of materials. I would like to make an outfit like this but I don't know what kind of tubing would be the cheapest with longevity and flexibility. I tried PVC tubing but it is far too rigid. I need it to be soft and to be okay in the washing machine. --78.148.110.243 (talk) 04:48, 6 January 2014 (UTC)[reply]

PEX tubing is designed for plumbing applications, so is flexible, especially the smaller diameters. I'm not sure how it holds up to washing, but my guess is it would be OK if you avoid bleach, which tends to make plastics brittle or tacky. StuRat (talk) 12:00, 6 January 2014 (UTC)[reply]
Not sure what you are up to. But PEX tends to be made from LDPE, which is a very crystalline material, and is going to be rather rigid. Silicone hose is very flexible and easily available up to 1 inch ID, there is also rubber hose, flexible ducting hose made from butyl rubber - why not check out materials at your local builders store? They tend to be helpful in that kind of places, talk to the oldest and grumpiest guy, that fellow will know best. 93.102.216.165 (talk) 17:55, 6 January 2014 (UTC)[reply]

Trinucleotide repeat mutations

I am watching a Genetics class on YouTube, and it discusses Huntington's disease and mutations due to wrong number of copies being made of the repeated sequences. Here's the link. One thing I don't get, is that he seems to be saying that the copying errors only happen between generations (of individuals). So in the graph in the video you see each individual have 2 gene lengths, one from each copy he or she has. From what the professor says, I gather that DNA polymerase slips up. But aren't genes also copied during normal cell division, and wouldn't therefore multiple cells of the same person be likely to have different number of repeats as well? Am I misunderstanding something? --108.202.177.21 (talk) 07:15, 6 January 2014 (UTC)[reply]

You're correct, the slip ups could occur during mitosis just as easily as they occur during meiosis. However, mitotic mutations are rarely as hazardous to health, and the reason is that any particular mitotic mutation will inevitably effect only a small portion of your body's cells (the rare times they do affect your health are usually cancer). So although a future brain cell might spontaneously get a lengthened huntington's gene, it will only be that one cell and its relative handful of descendants amongst the entire rest of your brain. Unless the mutation occurred very early in development to affect a large enough number of brain cells, you probably wouldn't notice. Someguy1221 (talk) 07:27, 6 January 2014 (UTC)[reply]
See trinucleotide repeat disorders. It looks like there has been some interesting recent work in understanding the condition further, including the role of various DNA polymerases, miRNA hairpins that are diced up (a sort of cellular anti-spam mechanism) and the 26S proteasome. [1][2][3] I don't know, but the explanation for why it changes more between generations could turn out to be complex, based on multiple factors. Wnt (talk) 08:32, 6 January 2014 (UTC)[reply]
Thanks! --108.202.177.21 (talk) 18:01, 6 January 2014 (UTC)[reply]

To know how is the score or grade calculated for natural essential oils.

I trade in natural essential oils ..and there are customers who ask me this question which am unaware of . so i want your assistance in this.

In natural essential oils what is the highest score or grade may be, usually a scale from low to high depending on what is the rule in the book. for eg: is a 10 the highest or is a 1 the highest score ? — Preceding unsigned comment added by 116.202.170.56 (talk) 09:47, 6 January 2014 (UTC)[reply]

Nah, I haven't come across this. I suspect some of your customers are thinking the oils may be diluted in a carrier oil, a common practice, e.g. for massage oils, and they want to know the percentage dilution. Ads for essential oils generally say 100% pure, so I guess that is the figure they are looking for.--Shantavira|feed me 12:20, 6 January 2014 (UTC)[reply]
The only grading system I've come across (I'm an aromatherapist) is with ylang-ylang essential oil, which comes in different grades. Our article says they are extra, 1, 2 or 3. Otherwise I agree with Shantavira. --TammyMoet (talk) 19:17, 6 January 2014 (UTC)[reply]

The eyes have it.

I can't find any pictures. Does Peters' four-eyed frog really live up to its name? Clarityfiend (talk) 10:31, 6 January 2014 (UTC)[reply]

Google image search gives some results, but none of them look particularly four-eyed to me. AndrewWTaylor (talk) 10:45, 6 January 2014 (UTC)[reply]
Could Peters have found a mutant, which did indeed have 4 eyes ? StuRat (talk) 11:56, 6 January 2014 (UTC)[reply]
There are other four-eyed frogs, named presumably because of their markings. Nothing in any of the articles suggests they have more than the usual two eyes. Ribbit.--Shantavira|feed me 12:14, 6 January 2014 (UTC)[reply]
The extra "eyes" are poison glands, and they're at the other end of the frog: [4]. --Amble (talk) 12:29, 6 January 2014 (UTC)[reply]
Great info. Would you like to add that to our articles ? StuRat (talk) 12:49, 6 January 2014 (UTC)[reply]
Sure, although that source is really just a blog. (That's not terrible but we can probably do better.) Here's a Google book result with some more info: [5]. I may have time to add the info later today, if someone else hasn't already done it by then. --Amble (talk) 15:15, 6 January 2014 (UTC)[reply]
Excellent. Thanks. Clarityfiend (talk) 00:44, 7 January 2014 (UTC)[reply]
I added a few sentences to the articles that already mentioned common names with "four eyes". I don't know whether that common name also applies to other species in the genus, or whether the glands are as visually prominent in all species. --Amble (talk) 14:42, 9 January 2014 (UTC)[reply]

Meaning of half-integer spin

Electron is a half-integer spin particle. But what is the meaning of half-integer spin? 106.209.249.198 (talk) 15:09, 6 January 2014 (UTC)[reply]

Does our Spin-½ article help?--Shantavira|feed me 16:31, 6 January 2014 (UTC)[reply]
Spin (physics) would be a good place to start. Red Act (talk) 18:18, 6 January 2014 (UTC)[reply]
At a really basic level, spin is quantized in units of the reduced Planck's constant. Every photon, red or blue, big or small, no matter how it's polarized, carries a spin of this amount. So a spinning particle can change spin by interacting with photons by increasing or decreasing by 1 of these reduced Planck's constant units at a time. Spin-1/2 particles are particles which have just two states, so they have to be 1 unit apart - but these are spins in opposite directions, which makes them +1/2 and -1/2. Wnt (talk) 18:29, 6 January 2014 (UTC)[reply]

Grrr...squirrels

One of these bushy-tailed rats is eating the outside trim of our bathroom. I looked him/her in the eye, through the window, but s/he didn't bat an eye and just kept on gnawing. What can I do to deter this beast? I've seen "deterrents" to use in the garden, and they basically tell you to boil water with chili peppers--what if I pour a bunch of hot sauce (Texas Pete, of course) on the window casing? Thanks, Drmies (talk) 15:12, 6 January 2014 (UTC)[reply]

Yea, I bet that would work. StuRat (talk) 15:43, 6 January 2014 (UTC)[reply]
Your last name does not inspire much confidence! :) Drmies (talk) 15:44, 6 January 2014 (UTC)[reply]
LOL. One downside of hot sauce might be that it could stain the wood red or brown. But, unless you have some clear liquid to repel squirrels, I'd say stained wood is better than chewed wood. You can always repaint it.
Also, I've noticed that squirrels don't see well through windows. I think they focus on the reflection rather than what's on the far side. Try knocking on the window next time and see them run like hell. StuRat (talk) 15:47, 6 January 2014 (UTC)[reply]
Well, this squirrel couldn't care less about growling, rapping, or knocking. Furry little shit. I'm gonna go with that hot vinegar, the little bottles with peppers in it--shouldn't stain very much. Thanks, Drmies (talk) 18:48, 6 January 2014 (UTC)[reply]
Problem squirrel? No problem! http://i.imgur.com/TJ4oo.gif — Preceding unsigned comment added by 217.158.236.14 (talk) 16:05, 6 January 2014 (UTC)[reply]
LOL. That video also illustrates my point about squirrels apparently not being able to see through windows. StuRat (talk) 20:29, 6 January 2014 (UTC)[reply]
If that squirrel didn't have a name, it must now be called Rocky! I don't think the RSPCA/SPCA would approve! O:-) 220 of Borg 09:40, 7 January 2014 (UTC)[reply]
In the UK you can get something called Squirrel Stop at garden centres, which is basically the same stuff as pepper spray. No doubt you can buy some equivalent elsewhere. Just spray it onto the trim.--Shantavira|feed me 16:36, 6 January 2014 (UTC)[reply]
Having rescued and raised orphan squirrels in the past, I can sympathize with your frustration with their obstinacy in this regard. The solution you proposed yourself is one of the more ideal ones, especially if you don't want to do actual harm to the critter (which it seems from your comments you don't). If you buy a commercial product, be sure you know its ingredients in detail, as oversight on these products isn't always the best (who all is really going to make a fuss if it harms the pest or kills it outright?), which can further be a problem if you have a pet capable of eating a squirrel corpse. All of that being said, there is also the more traditional method of fixing a replica bird-of-prey on the roof immediately above, but squirrels are quite clever and unlikely to be fooled indefinitely by this ploy. It's also worth noting that the squirrel is likely not eating the trim in the sense of consuming it; squirrels gnaw for a variety of practical reasons that have nothing to do with dietary needs. Primarily this behaviour is a result of the fact that, like virtually all rodents, their teeth grow for the duration of their lives and must be constantly worn down; generally the upper and lower incisors grow to meet eachother for this purpose, but in cases of malocclusion, it's possible the squirrel is chewing like crazy to forestall the eventual grisly fate of having the lower teeth puncture the roof of his/her mouth and grow into the upper skull -- it's not always so easy being a squirrel! Even squirrels lacking this condition tend to gnaw a great deal. Other reasons for this behaviour include to the production of nesting material and simply because the squirrel is trying to get at something or into somewhere. If you figure out the cause of the behaviour you may have still other avenues to explore. For example, if it's looking for nest material, you can always provide an alternative, if you don't have problems with being extorted by a rodent. ;) Good luck, and I hope you find a simple solution so the situation need not come to more drastic means; I know they can be irritating at times, but they really are cool little creatures and usually can be made to coexist without being too destructive to property with a little effort and luck. Snow (talk) 21:00, 6 January 2014 (UTC)[reply]
Yes, I wouldn't mind all the squirrels around my home if they hadn't broken into our attic (one also did a Santa impression and came down the chimney to leave us a few "gifts").
Leaving the squirrel a board to gnaw on might be a good idea, too. StuRat (talk) 21:20, 6 January 2014 (UTC)[reply]
Same here: they've lived in our attic before, and I can't help but think that this one was simply trying to bite its way in. The yard is full of trees and other woody material so there's plenty of other things to gnaw on. As far as my intent is concerned: I could want to kill them, but there's so many of them that there's no point to it. I do not believe this varmint scares easily easily and it clearly wipes its little rodent ass with my demands as a homeowner, so let's see how it handles Texas Pete Pepper Sauce, and what it thinks of the list of ingredients. Drmies (talk) 21:36, 6 January 2014 (UTC)[reply]
I picture it running really fast after it eats it, while yelling "Areba ! Areba !". StuRat (talk) 21:46, 6 January 2014 (UTC)[reply]
Arriba! Arriba! Richard Avery (talk) 07:45, 7 January 2014 (UTC)[reply]
God did not put squirrels on this earth to coarse this type of mayhem. He put them here so we could all enjoy squirrel pie. [6] More receipts here: [7] and here [8], Oh, and here as well [9]. In fact there, are so many edible solutions to this problem, that I wonder why squirrels have not been put on the Endangered species list. Mind you, I'm a fine one to talk – all I have in my fridge is several remnants of roast turkey, some two (?) week old minces pies and a lot of stuff that would require a DNA test to establish their origin. Ugh... Something in the back of the fridge just moved – is it coming out of hibernation?--Aspro (talk) 00:18, 7 January 2014 (UTC)[reply]
You could try hiring a falconer to go after the rats, too -- hawks just LOVE eating squirrel for lunch! Also, if you have a cat, maybe you could let it loose on the squirrels and see if that scares them away? 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:52, 7 January 2014 (UTC)[reply]
I was likewise thinking that if the OP could acquire the services of an owl or a falcon or a hawk, there's a good chance the squirrel population in that vicinity would decrease quickly, one way or another. Kind of a precedent for this approach occurred at the San Francisco Giants ballpark, which was plagued by various flocks of birds for some time, until hawks started hanging out there, and the other birds went away. ←Baseball Bugs What's up, Doc? carrots03:15, 7 January 2014 (UTC)[reply]
I was thinking more of San Jose State University, which had a huge population of squirrels until a pair of peregrine falcons built their nest on the roof of the new library, after which they thinned out the squirrels in short order. 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:28, 8 January 2014 (UTC)[reply]
You might want to talk to your local electric utility, while I don't have a reference at hand, at least here in west central Florida, squirrels chewing into electrical equipment for whatever reason are a significant cause of power outages.  — TimL • talk 22:28, 8 January 2014 (UTC)[reply]

White pepper powder. Deters most things that sniff around for their food.

Competition between aldol and Claisen

Hi, I don't know if this is the correct place to ask this question, but on the talkpage of user:Jü I have posted a question about competition between an aldol and a Claisen reaction, because I would like to write something about it on Wikipedia. Unfortunately, Jü was not able to tell me more about the various effects that can take place on those specific substrates, and I am not sure if I have the correct information to complement the article on aldol reactions. Please read this section first to obtain some background information. Thanks in advance! Best regards, Capaccio (talk) 19:24, 6 January 2014 (UTC)[reply]

Hoping to keep the existing discussion together, I responded there. But for anyone interested, executive summary is "it's well-known that esters are generally noticeably less reactive as electrophiles than aldehydes are". DMacks (talk) 22:11, 6 January 2014 (UTC)[reply]

Release static charge from reverse side of glass

I have a full size business office copier that copies through scanning – the paper run through and is scanned as it passes over the glass. Unfortunately, what happens sometimes is that little particles get stuck to the reverse side of the glass. When that happens your copies get lines in them because the copier is scanning each page across that glass with the object behind it. The way I fix this is to take off the glass and clean the backside of it but it's quite a pain. Is there a way to make the particles that are stuck on the back through static electricity fall away by neutralizing the charge from the other side of the glass so that the gass can remain in place? By the way, I am well aware that the methods proposed might be such that they would work, but also fry the copier's electronics. I am curious from an academic standpoint, even if actually doing the solutions proposed would be highly inadvisable.--71.167.166.18 (talk) 19:39, 6 January 2014 (UTC)[reply]

The preliminary question seems to be whether the static charge on the glass is positive or negative. In the former case, it should be possible to use an electron gun to remove the charge. If it's the latter, then a radioactive isotope which decays primarily via alpha particle emission might neutralize the glass. DavidLeighEllis (talk) 19:55, 6 January 2014 (UTC)[reply]
The idea of using alpha-radiation to discharge static sounds pretty scary - but those little brushes that photographers use do just that. They have a tiny amount of polonium 210 in them. SteveBaker (talk) 20:50, 7 January 2014 (UTC)[reply]
On a perhaps more practical note, one might be able to apply an antistatic agent to the reverse side of the glass, which could then be grounded. DavidLeighEllis (talk) 20:09, 6 January 2014 (UTC)[reply]
Wouldn't that prevent the xerox machine from working in the first place, because it DEPENDS on static electricity to make the toner stick to the copy? 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:46, 7 January 2014 (UTC)[reply]
The copier depends on the toner sticking to the drum, not the underside of the glass. DavidLeighEllis (talk) 17:37, 7 January 2014 (UTC)[reply]
Yes, exactly. I'd want to ask why the stuff is getting there in the first place. I suspect that there is some other component inside the copier that needs cleaning - and the lack of that is what's causing toner to get stuck under the glass. I'd suspect a grungy corona wire or something. SteveBaker (talk) 20:50, 7 January 2014 (UTC)[reply]

collapsible pneumatic (i.e. inflatable) rods/poles (as in a tent)

can you talk about the theoretics and practicalities of collapsible pneumatic (i.e. inflatable) rods/poles. I googled it but found this huge design: http://www.firstprincipals.com/Airzone.htm

Why are the 'rods' so thick (like a tire)? Couldn't they just be thin but at high pressure? What if they were made of stronger material, like Kevlar?

I presume the physics are kind of that tires need a little "give" so that's why they're larger. what about a collapsible pole? if the material is strong enough (kevlar/carbon nanotubing) can it be thin but very rigid? I'm just throwing out ideas. I don't know the actual physics, theoretical and practical, that govern this and would like to learn more. Thank you. 212.96.61.236 (talk) 20:25, 6 January 2014 (UTC)[reply]

Who would want to lug one of these out in to the wild to set up their tent?
When we're talking about supports like this, it's easiest to talk about them in terms of a Beam (structure), specifically Thin walled beams. The stiffness (and therefore strength) of these types of structures is essentially dependent on 2 things: the thickness of the beam, and the stiffness of the material. So, to make a hollow tent pole adequately strong, we can either make thin poles out of a really strong material (like traditional metal tent poles), or make thicker poles out of weaker materials (like the inflatable fabric ones you linked to). It's also possible to make a fabric structure stronger by filling with higher-pressure air (which effectively makes the walls stiffer by making it more difficult for them to move--think of something like a car's airbags, which look nice and fluffy but actually absorb quite a bit of force), but as you mentioned, there are practical considerations with both maintaining that pressure, and creating it in an environment where you would use a tent. 130.76.96.156 (talk) 21:24, 6 January 2014 (UTC)[reply]
(ec) How could you fill them with high pressure ? The idea of low pressure is so you can pump them up easily, say with a bicycle pump.
I would be concerned about the long term durability of the tent poles. I'd expect small holes to develop in them, making them useless until patched. StuRat (talk) 21:29, 6 January 2014 (UTC)[reply]


The tent example is just because that's what came up when I googled "inflatable pole." I was thinking like a piece of home furniture that would be pumped up once very slowly until it's incredibly rigid. What prevents this - the fact that rods aren't strong enough to support the high pressure? Would a theoretical more tensile material then support this usage case? Is it the 'risk' (i.e. explosion due to a pinprick.) I would just like to know where to start. In my mind's eye, it seems reasonable that a backpack could inflate, when plugged in, into a portable dresser for example. you just plug it in and it inflates. but the existing designs don't seem to make this practical... so...why not? 212.96.61.236 (talk) 21:57, 6 January 2014 (UTC)[reply]

It would never be like a solid object. The higher the pressure, the less it would compress when touched, but it would always compress somewhat. I don't think people want dressers that move when they put something on them (and I can't imagine the drawers sliding in and out on it). Of course, there are furniture items that people do like to be soft, like mattresses, couches, etc., so those could be made inflatable. One problem I've found with such items, though, is that they don't "breathe". Thus, your sweat doesn't evaporate through them, but rather pools up and becomes quite uncomfortable. This can be remedied by thick layers of cloth between you and the inflatable portion.
One other possible use for inflatable rods on furniture is as "bumpers". If you've ever stubbed a toe or hit your leg on a coffee table, you appreciate the need for these.
To add to the popping risk (better not have a cat with claws), the plastics might also outgas toxic chemicals into the air. Also, I don't think an inflatable membrane will last for decades, as most people expect their furniture to do. StuRat (talk) 22:16, 6 January 2014 (UTC)[reply]
So, I actually meant for portable furniture, like going to a hotel. If you are "okay" with the membranes buckling somewhat - could they be stiff enough under high pressure to be as good as weak unreinforced plastic/cardboard, for example? 212.96.61.236 (talk) 22:28, 6 January 2014 (UTC)[reply]
Sure, but what hotels don't provide furniture ? You'd probably still want some rigid pieces, like a wooden top for you inflatable table. Also keep in mind that pumps tend to make noise. Electrical pumps can be quite loud, while hand pumps are more quiet but take longer. And the guests on either side will probably suspect you are pumping up a rubber woman. :-) StuRat (talk) 22:36, 6 January 2014 (UTC)[reply]

I was just curious about it. For example lots of hotels don't really provide a truly large clothes rack. If it were a triangular type of structure with tessalated (triangular) sections that go down to the ground (i.e. feet that break it into sections) and an inflated center pole to hang things on (spaced by the feet), I wonder if it could support a decent amount of clothing hanging upright down from it. Also, after the initial pumping, why can't it stay inflated like a tire? Don't some airtight things hold pressure well? 212.96.61.236 (talk) 01:08, 7 January 2014 (UTC)[reply]

I think you're a little ahead of your time. I would expect that the same sort of people who came up with 3D printing will soon invent an addressible fabric - one which can be made to fold up in a wide range of origami patterns, complete with self-adhesions - and with a small hydrogen fuel cell and repetitive motion it should even be able to pump up its enclosed spaces to reasonable pressures. I dunno, I'll guess... 2019 for the press release. Wnt (talk) 05:46, 7 January 2014 (UTC)[reply]
Doing a google image search for inflatable beams gives some interesting examples! 122.108.189.192 (talk) —Preceding undated comment added 07:33, 7 January 2014 (UTC)[reply]
A collapsible clothes rack is probably easier to do without anything inflatable, especially if it doesn't need to be freestanding, but can hang off something like a curtain rod or the bathroom door. For example, you could hang a wire, with loops for each hanger, between two attachment points on opposite corners of the room. Think about how much more portable this would be than an inflatable unit and pump. StuRat (talk) 17:50, 7 January 2014 (UTC)[reply]
Something like this comes to mind...  :-) 130.76.96.155 (talk) 21:12, 7 January 2014 (UTC) [reply]
It's worth thinking for a moment about the math involved.
The problem with bend-resistance for long inflatable tubes is that the cloth offers great strength in tension - but almost zero in compression. So when the tube bends, only the pressure of the air inside resists that movement - and then only because of a reduction in the volume of the tube as it bends.
Imagine (for the sake of argument) a 5cm wide, square-cross-section tube. If you bend it through 90 degrees, then the volume inside the tube decreases by about 5x5x5 = 125cm3. If the cloth doesn't stretch at all - then the pressure inside the tube increases - but by how much depends on its length. So if the tube is one meter long - then the volume inside the tube is 5x5x100=2500cm3 and the pressure inside increases by about 5% - and that's what provides the force needed to unbend the tube. However, if you double the length of the tube - then the pressure increase is only 2.5% and the unbending force is half as much. If you reduce the diameter of the tube to just 1cm - then only 1cm3 of air is displaced and the pressure increase in a 1m tube only goes up by 1% - that's why fatter tubes work better.
In a real-world tube, the cloth is bound to stretch a little bit as the pressure increases - until it reaches some limit beyond which it won't stretch much more. That means that small pressure increases exert much less force on straightening the tube than you'd otherwise expect. Worse still, the volume of air that's displaced is going to be proportional to the sine of the bend angle - and sin(small-angle) is a very small number. So if the bend in the tube is only very slight - then the volume reduction will be very small indeed and the proportionate pressure increase will be correspondingly tiny. As the bend angle increases, the amount of volume removed goes up rapidly. That means that while you might make inflatable tubes that won't bend by a large amount - it's almost impossible to make tubes that are really stiff because small-angle bends produce very little pressure increase - and that's likely to be somewhat absorbed by the stretch in your cloth. So your tubes are basically going to be very floppy.
The trick here is to use inflatable tubes in structural ways that they are good at - which is not in copying the properties of a wooden or metal structure. Ideally, you want to be using them in compression along their length and in tension rather than in bend-resistance situations. That suggests that using groups of three tubes made into triangular 'trusses' would be a better way to build a structure using them.
SteveBaker (talk) 13:01, 8 January 2014 (UTC)[reply]

January 7

Records of variation in temperature

Does anyone know of any records (or interesting data) concerning wide variations in temperature readings? For example, (I am just making this up) ... On such-and-such a date, the temperature in such-and-such a city dropped (or rose) 75 degrees in a 24-hour period. Or that same type of data, perhaps in a one-hour period (or an even shorter interval). Another way to phrase this is that I am looking for the greatest temperature variation in the shortest amount of time. Thanks. Joseph A. Spadaro (talk) 03:44, 7 January 2014 (UTC)[reply]

See Chinook wind for one claimed record. Rmhermen (talk) 04:50, 7 January 2014 (UTC)[reply]
See heat burst for the extreme shorter time-period changes. StuRat (talk) 14:27, 7 January 2014 (UTC)[reply]
Spearfish, South Dakota and it's sourced. CambridgeBayWeather (talk) 18:21, 7 January 2014 (UTC)[reply]
And I now see that was also in the records section of Chinook wind.

Thermodynamics

Given the equation of state of a system (in the form of P=f(V,T)) can we find Cp, Cv and Joule-Thomson coefficient? I've been struggling to express these values in terms of derivatives of P, V and T with respect to each other and I've failed so far.--Irrational number (talk) 12:20, 7 January 2014 (UTC)[reply]

NASA SDO sun photo

Hi all,

This photo shows a picture of the sun taken by NASA. Here gives an explanation of what it is showing. It says that it shows wavelengths of 5800 Angstroms to 94 Angstroms, which it sort of says is where the normal yellow and green sections come from (although I'm not sure about that). What are the ranges of wavelengths for the other sections, what types of EM radiation do they represent? Are these standard for an image like this? Bonus points: Why are the features in each of the sections like that (i.e. different from one another)? Thanks! 80.254.147.164 (talk) 12:20, 7 January 2014 (UTC)[reply]

Different temperatures produce different wavelengths of radiation. This is similar to how when you heat metal it goes from red hot to white hot. Thus, by looking at different wavelengths of radiation, we can focus on different temperature features. The surface is relatively cool compared with the interior and the corona. StuRat (talk) 14:24, 7 January 2014 (UTC)[reply]
See Ultraviolet and False color. As far as I know, there isn't a convention for depicting the ultraviolet region of the spectrum, but I may be wrong. Tevildo (talk) 23:09, 7 January 2014 (UTC)[reply]

Brittle due to cold

What is the term for the temperature at which it is so cold that a malleable metal becomes brittle? (I want to find a chart for the temperature but don't know the name for what I'm looking for.) RJFJR (talk) 14:34, 7 January 2014 (UTC)[reply]

Toughness, the property of a metal to absorb shock without fracturing, is a function of temperature. You might be able to find data in a materials handbook or by scouring our articles and linked references for each metal of interest.
I found this conference paper, Low Temperature Metals, on Brookhaven National Laboratory's website. It has data and charts for common metals, and some exotic metals useful for superconducting research. The entire conference website has loads of other interesting reading material, too. Nimur (talk) 14:43, 7 January 2014 (UTC)[reply]
(ec) Note that it doesn't happen instantly at a certain temperature. Metals, and other materials, become steadily more brittle the colder they get. StuRat (talk) 14:55, 7 January 2014 (UTC)[reply]
The article embrittlement calls such a transition temperature the embrittlement temperature, though it specifically references plastics and rubbers, rather than metals. (Perhaps because of the gradual transition that StuRat mentions.) -- 160.129.138.186 (talk) 16:22, 7 January 2014 (UTC)[reply]
During World War II, several ships broke in half in cold waters due to embrittlement, the article on Liberty ships describes the phenomenon. Widneymanor (talk) 18:48, 7 January 2014 (UTC)[reply]
The Titanic may have also had rather brittle metal and rivets, in part due to the cold, contributing to the sinking. StuRat (talk) 20:08, 7 January 2014 (UTC)[reply]
On the radio this morning they said that the railroads are keep extra crews on hand because they are worried about the train tracks breaking because of the cold snap. RJFJR (talk) 21:19, 7 January 2014 (UTC)[reply]
An additional risk there is the metal contracting due to it's coefficient of thermal expansion. Then there's also frost heaving on the underlying soil to worry about. StuRat (talk) 23:35, 7 January 2014 (UTC)[reply]

"Bolingo fruit"

In a documentary on bonobos, it said they like to eat "bolingo" fruit. What species of plant is this? Is there a Wikipedia article on it? Here's a photo: http://www.pri.kyoto-u.ac.jp/hope/reports/23-001/1.jpgKeenan Pepper 21:23, 7 January 2014 (UTC)[reply]

Anonidium mannii --Dr Dima (talk) 21:35, 7 January 2014 (UTC)[reply]


January 8

HbA1c

Why is the "HbA1c" designation given to Glycated hemoglobin, i.e. why isn't it called something else? I understand that "Hb" stands for hemoglobin, but I can't figure out what the significance of "A1c" is. Since I know that HbA1b, HbA1d, HbA2c, HbB1c, etc., are all redlinks, I assume that it's not something sequential, and I know it's not a typo for HbAlc. Nyttend (talk) 01:51, 8 January 2014 (UTC)[reply]

We did this a month or two ago, I think. Turns out it's not Hb A1c but rather HbA 1c — that is, subtype 1c of hemoglobin A. I think there are probably subtypes 1a and 1b as well, but maybe just no one's gotten around to writing about them. But anyway if you search the archives it should show up. --Trovatore (talk) 01:59, 8 January 2014 (UTC)[reply]
Here you go: Wikipedia:Reference_desk/Archives/Science/2013 September 5#What is the meaning of A1C?. Look down for Nunh-huh's response; it looks like the most informative. --Trovatore (talk)
HbA = adult hemoglobin HbF is fetal hemoglobin HbA1a1 with fructose 1,6 diphosphate HbA1a2 with glucose 6 phosphate. Graeme Bartlett (talk) 02:12, 8 January 2014 (UTC)[reply]

Timber bridges

Cable-stayed Pomeroy-Mason Bridge in the USA

Why is it that timber is not used in bridges which require high loading capacities other than as decking? I am presuming it is because timber does not take axial load as well as rebar does but in the case of decking it is acceptable as it is likely to have more bending moments than axial loads, and timber takes bending moments better than concrete or rebar. Clover345 (talk) 15:57, 8 January 2014 (UTC)[reply]

Please define "high". Covered bridges went out of favor (from a structural perspective, not from an æsthetic or historic-preservation perspective) because they were more expensive than iron or steel in most places, and you also have the issue of timber being harder to produce in sizes that are good for long bridges. Imagine how hard it would be to get all the right timbers for something as large as the George Rogers Clark Memorial Bridge, for example. Nyttend (talk) 16:16, 8 January 2014 (UTC)[reply]
Also maintenance can be an issue. Steel just needs rust protection, and regular painting can prevent that. Wood, on the other hand, is vulnerable to dry rot, termites, burrowing beetles, woodpeckers, water damage, fire, etc. So, there's a lot more maintenance needed to keep wooden bridges in good working order. StuRat (talk) 18:09, 8 January 2014 (UTC)[reply]
As a terminological note, bridges aren't made of rebar, they are made of structural steel (Ok, maybe some people bridge their backyard creeks with rebar, but I suspect you're thinking about much larger bridges). The name "rebar" is generally reserved for unfinished, small diameter steel rods that are used in reinforced concrete. The structural steel article has a nice section comparing the pros and cons of steel compared to reinforced concrete.
As for your main question, there isn't much about timber bridges at bridge, but it does point out that most early bridges were not timber-only, but also used large amounts of masonry for structural load bearing. Timber bridge mentions that they are regaining in popularity in some areas, and has some good refs and external links, indicating they are currently used for high loads (i.e. automobile traffic), albeit for relatively short spans. The article and refs claim a ~50 yr life span, and comparable or reduced costs of construction and maintenance compared to other materials. Finally, timber is a renewable resource with (generally) lesser environmental impact than steel or reinforced concrete, and some governments might find that favorable. SemanticMantis (talk) 19:03, 8 January 2014 (UTC)[reply]
Steel and concrete don't seem like things we will run out of any time soon, being made from basic ingredients like iron, carbon, sand, lime, etc., which are abundant on the Earth. They also aren't particularly harmful to the environment, as the steel will rust away and the concrete break back up into rocks, in a few decades. StuRat (talk) 21:29, 8 January 2014 (UTC)[reply]
Off-topic rebuttal to Stu's speculation - SemanticMantis (talk) 22:16, 8 January 2014 (UTC)[reply]
:::I never said we were running out of steel. But it is not considered a renewable resource. That is not really up for debate. Also, you could have done a little googling about concrete, or even looked at our own environmental impact of concrete, which says "The cement industry is one of the primary producers of carbon dioxide, a major greenhouse gas." Additionally, the article outlines other detrimental environmental effects due to altered runoff patterns which can increase flooding, as well as urban heat island effects. I also did not say that concrete was commonly considered a pollutant. The key idea is that it takes massive amounts of energy to make steel and concrete, which generally adds to our global CO_2 emissions. In contrast, growing trees for timber removes CO_2 from the atmosphere, and can in some cases timber production can be considered a carbon sink, which is a technique for climate change mitigation. See also life cycle analysis. My point is, your statement that concrete isn't particularly harmful to the environment is just wrong, from several perspectives. Now I've gotten far off topic, so I'll quit :) In the future, please read my words and links carefully before you try to contradict them, or at least bring something besides your own assertions to the table. SemanticMantis (talk) 22:09, 8 January 2014 (UTC)[reply]
And while timber can be grown in a sustainable manner, it often isn't, with clear-cutting, cutting of old growth forest, and deforestation being the result. Even growing it in a sustainable manner requires adding access roads, which also gives access to hunters (whether legal or poachers), endangering wild animal populations. And the fact that timber bridges aren't likely to last as long means that the extra replacement bridges need to be figured into the environmental cost. StuRat (talk) 14:00, 9 January 2014 (UTC)[reply]
If CO2 is a "major greenhouse gas" like you say, and its levels are at an all-time high as they are, then why is it that we're freezing our butts off in the coldest winter since 1944??? 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:15, 9 January 2014 (UTC)[reply]
If you'd like to ask questions about climate change, feel free to open a new thread on the science desk. You can start by reading our articles on climate change, greenhouse gas and carbon dioxide. Also, at a basic level, you are confused about what is weather and what is climate. SemanticMantis (talk) 03:38, 9 January 2014 (UTC)[reply]
[ec with StuRat] Also please note that concrete and steel can be used to build bridge types that aren't timber-suitable. Timber can work well for a truss bridge, but a cable-stayed bridge (see picture) and a suspension bridge really need other materials. Nyttend (talk) 21:34, 8 January 2014 (UTC)[reply]
To reduce costs during construction, the railway viaducts in Cornwall (England) were initially wood and there is quite a comprehensive article on them at Cornwall Railway viaducts Widneymanor (talk) 21:37, 8 January 2014 (UTC)[reply]
Didn't you mean the railroad trestles in the 19th-century American Midwest? 2601:9:3200:467:6109:95AD:B0F7:600D (talk) 02:17, 9 January 2014 (UTC)[reply]

Repetitive driving but not Highway hypnosis

I was reading the Highway hypnosis article thinking it would be describing a common phenomenon I am familiar with but it didn't. I googled the term and could not find any references to what I, and I'm sure many others have experienced. I'n not sure what to call it... "Stop and Go hypnosis"? I only ever experienced it when I was in high school (I'm quite a bit older now). It was always during rush hour and very little attention was really involved, just follow the car in front of me until I get to my destination (it was a pretty simple route). Most mornings I would at some point become aware that I had arrived at my destination without any memory of the drive there. It seems like I would "zone out" and "Viola!" I was at school. It was a very repetitive boring task and only happened in the morning when I was tired. This seems quite unlike what is described in the Highway hypnosis article as I would still have had to obey traffic lights and the flow of traffic without ever so much as a fender bender or even a close call. It seems the task had become so repetitive that my mind "decided" there was nothing novel about it and hence no new memories to form. I'd be interested to hear form others who have experienced this or if anyone has run across a name for the phenomenon I am describing for which perhaps there is no Wikipedia article for, or perhaps the information is in an article I cannot find.  — TimL • talk 21:16, 8 January 2014 (UTC)[reply]

Yes, I've experienced that. And a twist is where you must take most of a common route, but then take a turn near the end to arrive at a different destination. I find it quite difficult to make that turn, as my brain "goes on autopilot" and I arrive at the more usual destination. I suspect a different part of the brain is guiding my driving in that mode, where rather than reasoning out turns and such, it's simply going off memory. StuRat (talk) 21:23, 8 January 2014 (UTC)[reply]
Ah yes, that too I have experienced (a common route with with a different turn for a different destination), I have at times in the past found myself driving to one destination when I meant to drive to nother if they involve a same comon route.  — TimL • talk 21:34, 8 January 2014 (UTC)[reply]
My uncle used to have a job that required him to drive to two different locations depending on which day it was. He had a note card on his dashboard that had an arrow on each side pointing in opposite directions. To remind him of which direction he should turn out of his driveway each morning, he would flip the card over the previous night. Dismas|(talk) 21:52, 8 January 2014 (UTC)[reply]
One of the main stretches I drive to go anywhere has four lanes, so I just have to remember to put myself in a different lane than the one I normally use for my commute if I'm going somewhere else. If I don't I'll end up at home or at work. Once, driving in from out of town I was on a road that used to be on my route to work and ended up automatically driving to my old apartment. The other thing about this "autopilot" mode that gets me is when something snaps me out of it on a rural route and I realize I don't actually know what road I'm on because I don't remember the last few turns. Katie R (talk) 13:35, 9 January 2014 (UTC)[reply]
(edit conflict)It's common enough that I was taught about it in Driver's Education back in the early 90s. And I've heard several people, both in my personal life and on television, talk about the idea of having gone through a stop sign knowing that they stopped but can't remember actually doing it. All because they've done it thousands of times before. I can't recall ever hearing a name for it though. Dismas|(talk) 21:24, 8 January 2014 (UTC)[reply]
This Reader's Digest article talks about it some. And Yale researchers have looked into it. Though I still can't find a name. Dismas|(talk) 21:30, 8 January 2014 (UTC)[reply]
Thanks. Your references seem to suggest it is a pretty common but little studied phenomenon. It's almost as if I was a philosophical zombie on those morning drives! I suspect we all are for short periods of time.  — TimL • talk 21:48, 8 January 2014 (UTC)[reply]
For the general phenomenon, see automaticity, which is the term used in psychology. Our article lists highway hypnosis as an example. Even though your example is different, it is, to my understanding, still an example of automaticity. If I had to talk about it in a formal setting, I might call it "automaticity of city driving". If you search google scholar for various combinations of /automaticity driving memory/ you will find some relevant articles. SemanticMantis (talk) 23:59, 8 January 2014 (UTC)[reply]
Perhaps Automaticity applies here, but thing is, it's not just that I had "automated" driving to school and thus didn't need to think about what I was doing, it was more like I was driving to school without any awareness at all!  — TimL • talk 00:29, 9 January 2014 (UTC)[reply]
That makes sense to me, it certainly feels that way. "Common route amnesia"?  — TimL • talk 01:10, 9 January 2014 (UTC)[reply]
Check it out, automaticity has been suggested to be moved to procedural memory. There's a subsection there, Procedural_memory#Expertise-induced_amnesia, that I believe describes this phenomenon very well. But this is not my area of expertise. Any thoughts (User:Looie496)? SemanticMantis (talk) 03:30, 9 January 2014 (UTC)[reply]
Automaticity does seem to describe this common phenomenon of driving a familiar route and not remembering it. If something unusual happens, such as an accident (hopefully not involving you), that will catch you attention because it's not part of the standard routine. I don't see this quote in the article, but I'm reminded of one of Yogi Berra's statements: "Ain't nobody can think and hit at the same time." An athlete trains himself in the mechanics so he can focus on the dynamics of a given situation rather than on the basics of "how to" do something. ←Baseball Bugs What's up, Doc? carrots04:53, 9 January 2014 (UTC)[reply]
Um, well, I don't actually know a whole lot about this. But that subsection looks like Original Synthesis to me, so I wouldn't say it forms a good basis for a move. Looie496 (talk) 04:54, 9 January 2014 (UTC)[reply]
The one difference is I had to be "half-asleep". I could always remember that I drove home, if not the drive itself. In the morning it was have if the drive had never happened, a somewhat disturbing phenomenon at first. It was a "How did I get here if I don't remember anything about the drive here?" sort of experience. It was more like an "automation coma" if I had to coin a term!  — TimL • talk 11:19, 9 January 2014 (UTC)[reply]
Yes, being sleepy does seem to figure in. Presumably the conscious part of the brain goes to sleep while the automatic part stays awake. I noticed when I took caffeine pills to stay awake for late night drives, this happened. That is, the caffeine kept my eyes opened, but the conscious part of the brain seemed to zone out. StuRat (talk) 13:44, 9 January 2014 (UTC)[reply]
It doesn't necessarily have anything to do with sleepiness. It can happen if you are intensely thinking about something unrelated while you are driving. It's just that either your episodic memory system doesn't form a record of events, or else that record is not easily accessible afterward. There isn't a whole lot of literature about this, but if you do a Google Scholar search for the phrase "driving without attention mode" (the name it was given by JS Kerr in a 1991 paper), you can find a few things. Looie496 (talk) 17:21, 9 January 2014 (UTC)[reply]
It is not just driving, it happens when you walk to work every morning as well. I cannot remember walking all the way to this building today, but I know I must have, since I am here. --Lgriot (talk) 09:26, 9 January 2014 (UTC)[reply]
  • I have always called this phenomenon of not consciously driving, driving on the reptilian brain. You can also witness its effects in other people. I normally try to drive at a constant speed slightly above the speed limit, and to avoid having a driver directly ahead of me. This means I am often either passing or being passed.
But you will notice on occasion someone will pull up behind you and just hover their, even in a relatively open road, where they could pass or at least switch lanes. You'll notice that if you gradually speed up or slow down they will stay with you. You can even gradually slow down to 10 or miles below the pseed limit. As long as the road is mostly empty, and they don't notice others passing, they will stay in place behind you for quite a bit. It is like they have joined your herd, and placed you in the role of lead stallion, so that they can turn their minds off and parasitize on yours.
After this has gone on for some while, you can break the spell by turning on your emergency blinkers. This has the brief effect of making it look like you have slammed on your breaks, although you haven't. They will also often then hit their brakes. Almost always they will then accelerate and pass you, often with a nasty, "you woke me up!", look. μηδείς (talk) 19:24, 9 January 2014 (UTC)[reply]

Text to 90999

The Red Cross says to do this to help people.

I looked at text messaging and I'm not sure this type of text messaging is described there.— Vchimpanzee · talk · contributions · 21:43, 8 January 2014 (UTC)[reply]

It is described at Mobile donating. I'll take a look at text messaging article to see if there is any reference to the mobile donating article. I googled "text messaging donations" to find the Wikipedia article.  — TimL • talk 21:53, 8 January 2014 (UTC)[reply]
I found what I needed at short code. Thanks.— Vchimpanzee · talk · contributions · 22:01, 8 January 2014 (UTC)[reply]
Just to note that up to 50% of the "donation" goes to the mobile service providers. It's better to donate via the organization's website.--Shantavira|feed me 09:37, 9 January 2014 (UTC)[reply]
All of these "Text XYZ to ###" messages are best ignored. They are unhelpful at best and complete scams at worst. If you really want to donate, either spend a lot (say >$100 via conventional means), or if you cannot afford that, don't donate and save for the next time. Paying for text messages to donate miniscule amounts is a waste. Somewhat off-topic, sorry, but in the long run it will get millions to the right places, rather than mobile network providers.217.255.149.135 (talk) 10:13, 9 January 2014 (UTC)[reply]
Not true. The only amount that goes to the carriers is whatever extra fee they charge for the text, if any. From www.mobilegiving.org, "100% of each donation is remitted directly from the wireless operators to the Mobile Giving Foundation, which in turns gives 100% to the recipient charity". mgive.org which the Red Cross uses has the same stipulation [11]  — TimL • talk 11:12, 9 January 2014 (UTC)[reply]

January 9

Water

What is the weight of (i) fresh water and, (ii) sea water - per cubic meter at say, 20 degrees c? Then, how many more times denser are these when compared with air? 202.53.237.198 (talk) 09:38, 9 January 2014 (UTC)[reply]

See the pages Properties of water, Seawater and Density of air. Answer: fresh water 998 kg/m3, sea water 1020-1029 kg/m3 and air 1.20 kg/m3, so water is roughly between 830 and 860 times heavier than air. - Lindert (talk) 10:08, 9 January 2014 (UTC)[reply]
Obviously those numbers are a little inexact because the density of air depends on temperature and pressure and also on humidity - so it varies quite a bit from place to place, from day to day and depending on the altitude that you measure it at. Sea water also varies in salinity (saltiness) depending on where you are and the depth at which you sample it - so the density can be quite variable...for example, there is a lot less salt in regions of the ocean when you're closer to the outlet of a large freshwater river or the outflow of a melting glacier. The density of water also changes quite a bit with temperature. SteveBaker (talk) 13:28, 9 January 2014 (UTC)[reply]

video of experiment in chemistry

Hi,
I'm looking for a tube or video of experiment in chemistry that can be preformed in high schools.
Does anyone have any idea?
Thank you. — Preceding unsigned comment added by 87.68.151.162 (talk) 17:20, 9 January 2014 (UTC)[reply]

Have you tried going to youtube.com and searching for "high school chemistry experiments"? Rojomoke (talk) 20:02, 9 January 2014 (UTC)[reply]
A search for "experiment in chemistry" turned up http://www.youtube.com/user/koen2all who has a bunch. Richard-of-Earth (talk) 20:50, 9 January 2014 (UTC)[reply]

help finding articles mentioned on wiki page

This Wikipedia page mentions some articles that my boss would like to read.

[1]

The articles are not in the reference list at the end of the page. They are not in the external links or further reading sections either.

Any idea how I would find the titles or journals, if not the actual articles, that are mentioned on the page?


130.132.173.15 (talk) 20:48, 9 January 2014 (UTC)[reply]

Footnote-referencing gets complicated on the ref-desks. Often clearer to just link to the WP article directly: Supraorbital ridge. DMacks (talk) 21:37, 9 January 2014 (UTC)[reply]
I added a note on Talk:Supraorbital ridge asking for help. Each article has a talkpage to help discuss/coordinate edits, so maybe someone who watches that article will be able to provide the missing information. Or if someone here has it, please add it there. DMacks (talk) 21:43, 9 January 2014 (UTC)[reply]
The article is in part based on an old (public domain) edition of Gray's Anatomy, so that is probably where those references are cited. The most recent PD version (from 1918) is online here Rojomoke (talk) 21:44, 9 January 2014 (UTC)[reply]
In the Further reading section, there are DOI links to online copies of the journal articles. Usually, you can view the summary but need to pay to read the entire article. ~E:71.20.250.51 (talk) 22:02, 9 January 2014 (UTC)[reply]
  • When you see weird shrapnel on Wikipedia articles, always click the History tab. Click "500" so you have some room to work in, and hunt around until where the shrapnel turns up, and by trial and error you can hit the revision (There's also a tool WP:Wikiblame but I forget where the link is) Anyway I quickly came up with [12] which says it is text taken from another article (for Endo and a few others - let me know if that isn't all of them) and also has a citation list. Wnt (talk) 22:11, 9 January 2014 (UTC)[reply]
That would be WP:WikiBlame (cap 'B') 71.20.250.51 (talk) 22:32, 9 January 2014 (UTC)[reply]
I got to work on the last section and found many of the references; my feeling is that the ones missing are probably better replaced with some later references that come up on search. It looks like Google Scholar is a good search for this topic - just go to scholar.google.com and put in "supraorbital", one of the author names mentioned, and optionally a year, and you'll come up with plenty, including less dated references. I'm afraid I'd have to get more interested in the science to finish the job, though... maybe someone else could lend a hand with this fascinating task? :) Wnt (talk) 23:03, 9 January 2014 (UTC)[reply]

Science of romantic relationships between ethnic groups

Is there any scientific evidence to suggest whether there is either a genetic based or environmental based preference for romantic relationships? Traditionally, people fell in love with their race but as different ethnic groups became integrated into multicultural societies, it seems that there are more inter-racial relationships than ever before. However, is there still a tendency to find the same race more attractive due to generics? Clover345 (talk) 22:13, 9 January 2014 (UTC)[reply]

Yes, there was a study in the 70's that showed sexual selection can be based on novelty. This encourages outbreeding, which leads to hybrid vigor. A quick search at google for novelty "sexual selection" brought up the very study in guppies I had remembered from the 70's. μηδείς (talk) 23:05, 9 January 2014 (UTC)[reply]
See also Claus Wedekind. There is significant evidence women prefer men whose sweat indicates they are as genetically unrelated in regard to their immune-system genes as possible. μηδείς (talk) 23:09, 9 January 2014 (UTC)[reply]
That would be MHC, see specifically Major_Histocompatibility_Complex_and_Sexual_Selection. As far as I know, MHC types can be the same between rather distantly related people, as well as different between rather closely related people. SemanticMantis (talk) 23:16, 9 January 2014 (UTC)[reply]

Ships

Apparently, and I have no reason not to believe this, if two large ships travel parallel alongside each other they experience a force which will tend to draw them together. I have heard that this is due to the increased flow speed of the water causing a pressure drop in this region (analogous to an aerofoil). However I have also heard that the effect is due to the ships edges acting as the plates in the Casimir effect and restricting the wavelength of waves which can be sustained by constructive interference too a small range of values, and that this imbalance towards the spectrum of waves on either side of the ships results in a net force pushing the ships together. Is it known if either or both of these explanations is correct? — Preceding unsigned comment added by 86.134.72.50 (talk) 00:43, 10 January 2014 (UTC)[reply]

Interesting question! I don't know, but for convenience here's Casimir effect. My ignorant guess is that appealing to quantum field theory for an explanation of behavior of ocean liners is at best metaphorical. But there is apparently a water wave analogue of the Casimir effect, and our article contains this nice video [13]. SemanticMantis (talk) 00:52, 10 January 2014 (UTC)[reply]

Propagator

Where does the formula : from the propagator article come from? 74.15.137.253 (talk) 00:54, 10 January 2014 (UTC)[reply]