Wikipedia:Reference desk/Archives/Science/2009 November 15

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November 15

Lucid dreaming

How can I develop this skill? —Preceding unsigned comment added by 79.67.82.206 (talk) 01:10, 15 November 2009 (UTC)

Did you try looking it up on Wikipedia, seeing as you are here? If you had, you would have very quickly found this: Lucid dreaming#Induction methods. --Tango (talk) 02:32, 15 November 2009 (UTC)

Yes thanks dont know how I missed that. Must have been asleep when I asked the Q--79.67.82.206 (talk) 12:12, 15 November 2009 (UTC)

Lucid dreams can be very hard work. It is funny when one wakes up from a realistic dream wherein he worked harder than in real life. I woke up from dreaming about having to devise computer systems for tracking billing and document management for a law firm, and designing a complete physical plant for the firm, all of which were far removed from tasks I ever did in a job. On waking, i felt ripped off, as if I had done work without compensation. Why would you assume lucid dreaming is a good thing? Edison (talk) 03:41, 15 November 2009 (UTC)

If it were really a "lucid dream", you would have known it was a dream, so you could have just told your boss to go jump in a lake. APL (talk) 04:35, 15 November 2009 (UTC)

Indeed. I think Edison is getting confused between "lucid" and "vivid". --Tango (talk) 13:25, 15 November 2009 (UTC)

I don't think you can develop it. There is no evidence whatesoever that these dreams are indeed lucid. As we can dream just about everything, we can also dream that we are lucidly (aka consciously) dreaming, just like we can dream we that we are cold, or hungry or whatever. It's an illusion. DVdm (talk) 13:34, 15 November 2009 (UTC)

Huh? I don't quite follow you -- would there be any empirical difference between actually dreaming, versus merely dreaming that you are dreaming? I have lucid dreams occasionally (not deliberately induced), and I find that I can easily make myself wake up from one if I want to. It seems to me that that's inconsistent with what you're saying, but I'm not sure I actually understand you. Looie496 (talk) 18:09, 15 November 2009 (UTC)

"I can easily make myself wake up from one if I want to." ==> You mean that you dream that you easily can make yourself wake up.

We dream that we can can fly. Do we actually fly?

We dream that we can make ourselves wake up. Do we actually make ourselves wake up? You might think so, but I don't - we just dream it.

We can dream anything, remember, so why not this?

Perhaps this clarifies :-) DVdm (talk) 19:15, 15 November 2009 (UTC)

I lucid dream and sometimes it goes a bit all wrong, and I concetrate extremely hard on moving my real life arm instead of my in dream arm and it wakes up. Like, actually wakes me up in real life. I've done it relatively consistently so it's not just a coincidence. Plus if you're aare you're dreaming then you're aware you're dreaming, surely that's that? 82.11.245.145 (talk) 19:48, 15 November 2009 (UTC)

I don't think so. If you think you are aware you're dreaming then surely you agree that you are dreaming. Now, what are you dreaming? You are dreaming that you are aware you're dreaming. DVdm (talk) 19:50, 15 November 2009 (UTC)

But I'd say lucid dreaming is being aware you're dreaming, and if you know you're dreaming in any sense I'd say you are lucid. Generally realising you aren't awake whilst in a dream would be lucid to me in some way, even if you are dreaming you're dreaming. I get what you're saying, but it seems more philosophical/a technicality than anything. Guess it depends on how you think of the term. Jimothyjim (talk) 20:02, 15 November 2009 (UTC)

Well, starting from the premise that one can dream anything, I just apply Occam's razor in this case. I always found this a school book example.

Cheers, and sweet dreams :-) DVdm (talk) 20:36, 15 November 2009 (UTC)

Nonsense. First of all, in it's purest form, a "lucid dream" is just a dream where you're aware that you're dreaming. There's no difference between being aware of something during a dream, and dreaming that you are aware of something. Perhaps you're objecting to the idea that dreams can be controlled. That's entirely testable. (By the dreamer, perhaps not by an outside observer) People who can lucid dream often decide before they go to bed what direction they'll take a dream in. Since this is typically a direction that their dreams to not normally go in (else, why bother?) and since they are typically satisfied with the results, I deduce that lucid dreamers are getting results far better than random chance.

Incidentally, I'm not sure if this is a correct application of Occam's razor. You're positing an unusual sort of meta-dream. Why does this multiply entities less than positing a lucid-dream? APL (talk) 00:52, 16 November 2009 (UTC)

"First of all, in it's purest form, a "lucid dream" is just a dream where you're aware that you're dreaming." ==> Yes, like you say, "a dream where you're aware...". So you dream that you're aware that you're dreaming. That does not mean that you are aware.

"There's no difference between being aware of something during a dream, and dreaming that you are aware of something. " ==> Of course there is a difference, just like there is a difference between feeling cold during a dream, and dreaming that you are feeling cold.

"... the idea that dreams can be controlled. That's entirely testable. (By the dreamer, perhaps not by an outside observer)" ==> So it is entirely un-testable and, what's more important, un-falsifiable, which makes it useless idea.

"You're positing an unusual sort of meta-dream." ==> On the contrary. We can dream anything... hunger, awareness, joy, illusion of control, fear, lucidy, extasy... There is no meta-level anywhere near. That is Occam in action.

But hey, don't let me spoil your dreams. By all means enjoy the illusion that you really honestly have control. I just don't buy it :-)

DVdm (talk) 08:37, 16 November 2009 (UTC)

No, seriously. You've got logical errors here. For starters, your abuse of the word "anything" can cut both ways. I could say "If I can dream anything then I can dream precisely what I want to in a wholly interactive way." and it would be just as valid as what you said.

Secondly, not strictly a logic problem, but I still don't see how Occam's famous problem-solving technique applies here. Lucid Dreaming is entirely testable by the dreamer, (As I explained above) and many lucid dreamers claim to have done so. You're positing that they're lairs.

Thirdly, While it annoys those of us who prefer the hard sciences, you can't dismiss, out of hand, phenomena that rely on self-reporting. Otherwise you've just dismissed the largest fraction of psychology, and a significant fraction of medicine. (How do we know that painkillers work?)

Fourthly, but not finally, "Feeling cold" is a perception. Feeling cold during a dream and dreaming that you are feeling cold are the same perception, even if the causes are different, so your example in that case is flawed as well.

Finally, and most importantly, you're ignoring the fact that communication from a dream to reality is entirely possible. So lucid dreaming is entirely testable by third parties. Studies have been done where lucid dreamers have been instructed to perform certain actions, (clench their fists, move their eyes in a particular unusual pattern, etc.) and they were able to successfully do this even when polygraph machines proved that they were asleep. Two such studies, in reputable journals are used as references in the introduction to the article Lucid Dreaming.

(For the record, I cannot lucid dream, I am simply objecting to your misapplication of logic to 'disprove' a common phenomena.)APL (talk) 15:33, 16 November 2009 (UTC)

Very well put, APL. In the same vein, how could you say that the "illusion" of being aware is any different than "actually" being aware? Either way, you are perceiving the same thing. —Akrabbim^talk 15:42, 16 November 2009 (UTC)

I will only comment on your first sentence: "I could say "If I can dream anything then I can dream precisely what I want to...".

==> You still don't get my point. You can dream that you-can-dream-precisely-what-you-want, because dreaming-precisely-what-you-want belongs to "anything".

I think I have repeated myself sufficiently now. For those who still don't understand, don't worry - and don't lose any sleep over it :-) DVdm (talk) 15:47, 16 November 2009 (UTC)

"I think I've repeated myself sufficiently now. No matter how many times I keep repeating exactly the same thing people just keep pointing out the flaws in my logic, my poor understanding of the topic under discussion, and referencing legitimate scientific evidence that I am exactly wrong, It's sad really. Still, a man can only mindlessly repeat the same thing so many times before he's forced to give up on the sad souls who won't listen to his brilliance." APL (talk) 15:58, 16 November 2009 (UTC)

I had a dream once where I was going to do something illegal, but then I realized I was dreaming, so it was ok for me to do the illegal thing since it wasn't real. Ariel. (talk) 08:23, 16 November 2009 (UTC)

Yes, you had a dream once. I had one too :-) DVdm (talk) 08:37, 16 November 2009 (UTC)

I had a dream once where I was Lucid, I can't remember what I was doing, but at the same time I was listening to the TV in the real world. And I wasn't just dreaming I was listening to a real world TV, because when I woke up again I checked the NFL game and everything I had heard whilst dreaming had happened in the game. That's not technically lucid dreaming as something else, but my point is that dreaming isn't a clear cut thing, just cause you can't do it doesn't mean it's not possible. Some people can remember insane amounts of numbers and stuff, and I can't do that but I don't deny others can. The mind is pretty much impossible ot understand at the minute, but it seems odd to disregard things like Lucid dreams. Jimothyjim (talk) 11:59, 16 November 2009 (UTC)

Sure. I had the same experience many times and we probably all have. But note that I don't disregard lucid dreaming - I just find it a hell of a misnomer. DVdm (talk) 12:21, 16 November 2009 (UTC)

I think DVdm is like an ancient Greek philosopher here. He's tumbled onto an explanation of a natural phenomena that is elegant in it's simplicity and has all the grace and symmetry of the finest zen koans, and he refuses to let go of this explanation even when the real world turns out to be more complicated than his initial assumptions. APL (talk) 16:50, 16 November 2009 (UTC)

It's not any sort of explanation in the first place. There is no such thing as "an illusion of being aware". That was Descartes' irrefutable point with his famous line cogito ergo sum, "I think, therefore I am", which many people these days misunderstand.

By the way, DVdm also goes off the track a bit by equating "lucidly dreaming" with "consciously dreaming". When you are dreaming, quite obviously, you are conscious, whether it's a lucid dream or not. You are not conscious (or at least not very) of external stimuli, but that's another matter: You are able to perceive and think, even if your perceptions are internally generated. --Trovatore (talk) 20:23, 16 November 2009 (UTC)

Hunger

Why do I feel hungry about every 5-6 hours while awake, but not when asleep. When I wake up at night I may feel hungry but if I go back to sleep without eating, then, when I wake up in the morning, Im no hungrier than normally at breakfast. Whats going on here? —Preceding unsigned comment added by 79.67.82.206 (talk) 01:14, 15 November 2009 (UTC)

Circadian rhythm, or something similar - hunger isn't only caused by a need for nutrients, your body is conditioned to expect foods at certain times and not to expect them at other times. Vimescarrot (talk) 01:22, 15 November 2009 (UTC)

Sleep is a pleasure too. You have two competing pleasures — sleeping and eating. Why waste good sleep on mundane eating? Bus stop (talk) 03:47, 15 November 2009 (UTC)

You also have a much larger demand for nutrients while awake since you are actually up and about and doing things. Sleeping doesn't require much energy at all (no walking, no intense thinking), so you can make it pretty far on not very much. ~ Amory (u • t • c) 19:47, 15 November 2009 (UTC)

Phone and Paper Shredder

Many times when I receive a cell phone call in my bedroom where my paper shredder also happens to be, the paper shredder will start running (as if I inserted paper) just before the phone rings and will continue to run until I pick up the call. Why does this happen? 69.115.152.137 (talk) 01:32, 15 November 2009 (UTC)

Do the clocks start running backwards when someone rings the doorbell as well? :) Perhaps it's interference. DRosenbach ^{(Talk | Contribs)} 03:10, 15 November 2009 (UTC)

...don't you love flippant responses? Actually it is possible that pre-ringing interaction between your cell phone and the cell towers are responsible for your cell transmitting at a frequency and intensity that triggers the circuitry f the switch that belongs to the paper shredder activation circuit. For instance if the switch is based on a light sensor then the radio frequency may cause the light sensor circuitry in the shredder to activate as if the light beam were interrupted. In some cases all it take is for the signal traveling to the sensor sent by the light beam to deviate from phase or frequency to activate the circuit. 71.100.7.164 (talk) 03:29, 15 November 2009 (UTC)

It could be electromagnetic inductance from the cell phone triggering the circuit on the shredder which detects the introduction of paper to be shredded. Or perhaps the house is built over an old Indian (Native American) burial ground, and poltergeists are at work. Edison (talk) 03:35, 15 November 2009 (UTC)

Right before a cel-phone rings there is a lot of communication going back and forth between the tower and the phone. This interferes with a lot of things. Most commonly people notice this as interference in speakers. Just like speaker wires can pick up the signal, probably there's a wire between the "paper sensor" and the chip the controls the shredder that's picking up this interference. If I had to guess, I'd say that the sensor is probably analog (Optical, perhaps?) with a very tiny voltage difference between "paper" and "no paper". APL (talk) 04:33, 15 November 2009 (UTC)

The shredders I've used have had a mechanical switch that the paper operates. Any design that is capable of being turned on by simple interference sounds dangerous (even if nothing is near the paper slot, the motor could overheat). I would suggest getting rid of the shredder or at least keeping it unplugged when not actually in use. And if it operates even when unplugged, call an exorcist. :-) --Anonymous, 05:50 UTC, November 16, 2009.

Nah, most shredders today use a light sensor and a diode. Mechanical switches tend to clog. But you are right about the overheating part - I hope the motor has protection circuitry in it. There are many kinds of proximity sensors, maybe one of them is affected by strong radio waves. Ariel. (talk) 08:20, 16 November 2009 (UTC)

cancer

Cancer is a mutation of normal cells characterized by uncontrolled growth. If a GM corn or flax cell that produces insecticide gets cancer is it also characterized by uncontrolled growth? 71.100.7.164 (talk) 02:21, 15 November 2009 (UTC)

So you sort of answered your question by defining cancer as mutations that promote uninhibited growth. DRosenbach ^{(Talk | Contribs)} 03:11, 15 November 2009 (UTC)

Only if my understanding of what cancer is or does is correct. 71.100.7.164 (talk) 03:22, 15 November 2009 (UTC)

Plants don't exactly get cancer. Plants can get tumors, but it's not really cancer because it can't spread like it can in animals. Cecil Adams touches on this briefly here. APL (talk) 04:23, 15 November 2009 (UTC)

Your question would make a lot more sense if you began with "Cancer is a mutation of normal animal cells characterized by uncontrolled growth." By redefining a common term, you can make up any ridiculous question you like. For example, I could ask: "If radiation contamination is caused by any exposure to sunlight, are all GM crops grown outside full of radiation contamination?" -- kainaw™ 04:39, 15 November 2009 (UTC)

I don't disagree with you and you are making a reasonable point but where I live there are a lot of phosphate mines and a lot of unmined phosphate. It is ver common to see trees with so called tumors but due to their encompassing size in some cases the tumors are larger than the tree. Although they are usually adjacent to each other and a dividing line is hard to establish between adjacent tumors and they appear not to have been transported to other parts of the tree through the veins of the tree they are obviously uncontrolled growths everyone assumes to be from radon gas or a radiation based interference with genomes, even though hey might be the result of a tumor causing virus. 71.100.7.164 (talk) 08:14, 15 November 2009 (UTC)

Might they be galls? -Craig Pemberton 09:00, 15 November 2009 (UTC)

These nodules, growths, tumors are very large, the largest mass of tumors surround a thirty foot oak tree at the trunk from a foot above the ground to six feet above the ground, if memory serves me correctly. Unless galls are consistently this massive then I can't explain the number of trees effected. 71.100.2.243 (talk) 11:38, 15 November 2009 (UTC)

Could be nematodes or fungi. Fences&Windows 15:29, 15 November 2009 (UTC)

Plants can't get cancer as such because their cells cannot undergo metastasis. But they do get tumour-like growths such as crown galls caused by Agrobacterium tumefaciens. Fences&Windows 15:22, 15 November 2009 (UTC)

Metastasisless malignancies are still malignancies -- basal cell carcinoma is cancer even though it rarely metasticizes. If it would never metasticize, it would still be categorized as cancer because metastasis is just one of the many surrogate biomarkers signs, so to speak, of cancer. (pre)Cancer is diagnosed prior to metastisis based on histologic findings such as mitotic figures, metaplasia/dysplasia, epithelial invasion of the lamina propria, etc. DRosenbach ^{(Talk | Contribs)} 15:41, 15 November 2009 (UTC)

Why do plants get tumors from infection by other organisms only? 68.193.225.106 (talk) 16:06, 15 November 2009 (UTC)

I'm not sure if that is true. On a slightly different note, cancer is commonly linked to infection. -Craig Pemberton 08:33, 16 November 2009 (UTC)

Evolutionary advanage of nervousness?

It seems that nervousness would be a severe detriment to survival, due to making tasks which are important to survival more difficult to perform successfully. Yet somehow nervousness hasn't been eliminated by natural selection. What survival benefit does nervousness provide that has caused this? --75.39.194.221 (talk) 02:23, 15 November 2009 (UTC)

This emotion is supposed to stop the animal from doing something risky, such as showing itself in front of a predator, eating a strange new substance, driving too fast, straying too close to a cliff edge, or jumping from it. Graeme Bartlett (talk) 02:35, 15 November 2009 (UTC)

Nervousness is supposed to stop you doing whatever it is, that is the point. What important things were there for proto-humans (or earlier animals) to do that would make them nervous? I can't think of any. Anything that would make them nervous would be something that they shouldn't do. Eg. you see a big lion sleeping next to the tree you want to pick fruit from you don't overcome your nerves and creep up to the tree, you go and get your dinner somewhere else. --Tango (talk) 02:56, 15 November 2009 (UTC)

I suppose the opposite of "nervousness" would be fearlessness. "The lion is sleeping next to the tree with the fruit I want to eat. I will climb up on the sleeping lion to reach the fruit. If the lion wakes up, I will simply spit in his eye." Very brave, but the individual might not survive to pass on his genes to the next generation. Edison (talk) 03:32, 15 November 2009 (UTC)

Emotions are complex. Nervous is a general term covering many emotional states. As you point out, nervousness can be detrimental. I don't think evolution is the best place to look for evaluating nervousness. Emotions may not leave traces as easily understood over the periods of time involved in human evolution. We may not really be able to know what advantage or disadvantage various emotional states, among them the many types of nervousness, have played at the various stages in the role of human survival over the periods of time in question. Bus stop (talk) 03:35, 15 November 2009 (UTC)

Like most behaviours, nervousness can be dysfunctional in some cases, but in others there would be a survival benefit to having second thoughts, being overly cautious, or even being visibly nervous which could alert other group members or even lead to a better-qualified member taking action. Also you're only likely to overcome nervousness if you judge that the action truly is important, so it screens out casual risk-taking. Peter Grey (talk) 03:53, 15 November 2009 (UTC)

I find that nervousness is usually quite justified. What's the point of embroidering your quilt if you have the notion that a sabretooth tiger is nearby? Vranak (talk) 04:19, 15 November 2009 (UTC)

That's right, put down the quilt, grab your spear, and get yourself a nice sabertoothed fur, instead. Much warmer than a quilt. StuRat (talk) 05:12, 15 November 2009 (UTC)

I've noticed a huge difference in the skittishness of flying insects. If they are sitting on a wall when I enter a room, some will start flying and taking evasive action immediately, while others will let you walk right up and grab them. I have more trouble understanding the latter behavior. I'd expect them to give their camouflage a chance to work, but, at some point, I'd also expect them to realize I've spotted them and flee (or flea, as the case may be). StuRat (talk) 05:17, 15 November 2009 (UTC)

Maybe they were asleep. --Tango (talk) 06:15, 15 November 2009 (UTC)

And they might not be intelligent enough to cope with the unusual environment (big homogeneous wall painted with only one color) --131.188.3.21 (talk) 10:36, 15 November 2009 (UTC)

Pure conjecture here, but the presence of individuals with crippling nervousness or brash bravery in a population might be understandable in terms of heterozygote advantage and balanced polymorphism. -Craig Pemberton 08:57, 15 November 2009 (UTC)

It could be, but I think it is more likely explained by nurture rather than nature. Crippling nervousness usually has an identifiable cause (yelling at your children over minor things a lot tends to make them generally nervous, for example). I think brashness is usually caused by over-estimating ones own abilities rather than bravery - that, and being drunk. --Tango (talk) 09:06, 15 November 2009 (UTC)

Fear and Risk aversion might help, and see The psychology of risk taking behavior. Nervousness isn't per se a pathology, the balance of whether to take risks or not - which is really what underlies nervousness - is something that affects most animals. Work in animal behaviour and ecology often talks about 'neophobia', which is a version of nervousness. "What important things were there for proto-humans (or earlier animals) to do that would make them nervous? I can't think of any." New sources or types of food, crossing rivers, climbing trees, extra-partner mating, predators or other groups of hominids nearby, etc. Fences&Windows 15:13, 15 November 2009 (UTC)

How long will lunar water last?

Scientists have recently confirmed the presence of large amounts of water on the moon. Has anyone done any work estimating how long that water is likely to last if we start using it? Are we likely to hit peak water on the moon at some point? I know we don't have any idea precisely how much water there is on the moon and we don't know how much water we are likely to want to use in the future, but does anyone have a rough order of magnitude? Is there enough for a few decades? A few millennia? Millions of years? --Tango (talk) 04:46, 15 November 2009 (UTC)

I believe you are viewing lunar water as a pure consumable, not a recyclable resource. There is no reason to assume that the water harvested from the Moon won't be recycled over and over as long as it is needed. The issue, from my point of view, is not if we will use it all up. The issue is how many people can the water on the Moon support? -- kainaw™ 04:51, 15 November 2009 (UTC)

If just small amounts are used to replace losses in life support systems, that might be the case (but it probably wouldn't - the lunar bases will almost certainly be in illuminated parts of the moon, at least partially, and water that escapes there would be heated up to sufficient degree to escape the moon's gravity). If large amounts are used to make rocket fuel (which is one of the common proposals) it certainly isn't. --Tango (talk) 06:14, 15 November 2009 (UTC)

Water on Earth is not likely to leave the hydrosphere, but water on the Moon could escape if exposed to the vacuum, so it would be in part non-renewable, with a little replacement by comet impacts. Of course, right now none of it is being used. Peter Grey (talk) 05:29, 15 November 2009 (UTC)

They blasted a 60-100 ft crater with their impactor, equivalent to a volume of 100 thousand to 1 millions gallons of disturbed regolith. As a result approximately 25 gallons of water was kicked up into space in a way the satellite could detect. So we can set a lower limit on the concentration of ice in this permanently dark crater at 25 parts per million by volume (but possibly quite a bit higher). That's not a high concentration, but on the other hand, it would suggest one could get ~100-300 tonnes of water per km² in craters such as this. The space shuttle external launch tank carries about 700 tonnes of fuel for comparison. So, the dream of using water for fuel would seem possible, but not very easy since very large areas may need to be mined. Dragons flight (talk) 10:51, 15 November 2009 (UTC)

Water on the moon is really important to the future of humans in space. How long it lasts depends on what we use it for. If people merely live on the moon - then it can be recycled. We'll need oxygen to breathe and water to drink - and both to raise food - but that could all be recycled (at least in principle - there would of course be losses). With care, it could support a lot of people for a long time - but no recycling will ever be perfect - so it can't last forever. But there is another important use for lunar water. If we use cheap solar power to split lunar water into hydrogen and oxygen - we can use that as rocket fuel - very handy for trips to other planets and such like because we don't have to haul it up from the earth's gravity well. In that case, the water is certainly not recyclable and we would undoubtedly slowly consume what's there. We can't tell how long it'll last unless we know:

• How many people are using it.
• How efficiently are they recycling it (if at all).
• How much is taken off the moon in the form of rocket fuel or whatever.
• How efficiently it can be mined.

In the long run, I'd hope we'd use the moon intelligently - as a stepping stone. There is plenty of even more useful water "out there" in the form of comets, small moons, Saturn's rings and asteroids - we just need a way to get to it - and the moon is a good place to start. For example - if we mined Halley's Comet (picking a comet at random!) - it appears to be approximately 80% water and it's about 1000 cubic kilometers in size. That's a truly insane amount of water! (In reality - we'd want to pick a comet in a more nearly circular orbit.)

We need to use the water on the moon wisely to allow us take that next step.

SteveBaker (talk) 01:19, 16 November 2009 (UTC)

There has been a lot of work done in how to use lunar resources, I was wondering if anyone knew of any work done on estimating how much we would need and how long it would last. I know we can't get accurate answers, but some rough Fermi calculations should be possible to get a range of orders of magnitude. --Tango (talk) 01:28, 16 November 2009 (UTC)

At current moon water usage rates, it should pretty much last forever. Googlemeister (talk) 17:31, 16 November 2009 (UTC)

Copepod parasite?

Anterior bit of the copepod.

Higher magnification.

I found this copepod with an egg sac today. There is some sort of tubular structure in the egg sac. My first guess was that this was how they attached their eggs, but I don't see a similar structure in photos of other egg sacs. Could it be a parasite? Or maybe someone got stuck in egg adhesive and is unwittingly along for the ride? -Craig Pemberton 08:46, 15 November 2009 (UTC)

How do paramedics repair severed arteries?

When a paramedic, combat medic, or some other first response health provider encounters a person with a severed artery (or vein I suppose) that needs treatment right away (i.e cannot wait for transportation to a hospital), what do they typically do to treat the person? Do paramedics carry an "artery repair kit"? Also, how is an artery repaired and is there any difference between how a first response surgeon with limited equipment and a someone in a hospital with the full breadth of equipment would go about reconnecting an artery? I tried looking for information and some websites mentioned stitches and grafts, but I don't think I got an accurate picture of how the severed ends are actually stuck back together. 96.253.247.216 (talk) 10:04, 15 November 2009 (UTC)

They won't repair the artery. They will stop the bleeding through a combination of direct pressure, elevation, pressure points and, as a last resort, a tourniquet. The artery will be repaired by a surgeon once they get to hospital. --Tango (talk) 10:12, 15 November 2009 (UTC)

Regarding the second half of your question, the most commonly-used technique for repairing an artery was described by Alexis Carrel in 1902 (Lyon Med 1902; 98:859–863, too early to appear in Pubmed) and illustrated here. The arterial wall is fragile and all three layers (intima, media, adventitia from inner to outer) must be rejoined in the repair, because separation and retraction of one or more of these layers, i.e. delamination, is common with severed arteries. This is made even more difficult because direct clamping or grasping with forceps can damage the arterial wall and 'kill' it (it is living tissue, after all). Thus, arterial repair is a fairly demanding task - not saying it couldn't be done in the field, but it would be a serious challenge. -- Scray (talk) 15:52, 15 November 2009 (UTC)

Thanks very much for the answers! 96.253.247.216 (talk) 22:25, 15 November 2009 (UTC)

How to apply a pressure dressing 75.41.110.200 (talk) 23:14, 15 November 2009 (UTC)

Paramedics provide first aid. Vascular surgeons reconnect arteries in operating rooms. There is a century of medical technology and about 10 years of training difference between the two. alteripse (talk) 13:49, 17 November 2009 (UTC)

Psychology

Hi, I know a person who is always very calm and it seems like nothing can surprise her.She never shows any emotions. If something strange or incredible happens, she just says "Oh." or smth like this. (Like Robin from Robin (TV series) if you know it...) Once I've heard of alexithymia but I'm not sure she has it because she can recognize other people's feelings very well. She is quite lonely and doesn't talk much to other people because she talks very silently and no one hears her. She really can't express herself and I feel sorry for her. Any ideas which illness could this be? —Preceding unsigned comment added by Atacamadesert12 (talk • contribs) 10:53, 15 November 2009 (UTC)

I afraid we can't make diagnoses here. You will need to consult a professional. --Tango (talk) 11:02, 15 November 2009 (UTC)

This question appears to be a request for medical advice. It is against our guidelines to provide medical advice. You might like to clarify your question. Thank you. Responses containing prescriptive information or medical advice should be removed and an explanatory note posted on the discussion page. If you feel a response has been removed in error, please discuss it before restoring it.

This removal is discussed here -- Scray (talk) 16:02, 15 November 2009 (UTC)

The common element whenever you observe these strange behaviors is that you are observing her. If you cease observing, perhaps the symptoms will also disappear! Vranak (talk) 15:50, 16 November 2009 (UTC)

Too many possibilities. According to FlashForward she has addisons (joke), she could also have aspergers or (light) autisim. Or she's just not an emotional person, or just shy. There is no way someone on wikipedia could help you diagnose. But if you want to help, how about just sitting silently (with her) and letting her be herself before trying to change her. See what she does by herself, and then you do the same, but with/near her. Maybe you'll learn more about her. Ariel. (talk) 08:15, 16 November 2009 (UTC)

Queen Ant

I have a queen ant and she has laid some eggs. When the eggs hatch what will the little worker ants need to be fed? I know in nature they'd eat dead files or stuff, but in captivity what can I give them? —Preceding unsigned comment added by 82.43.89.85 (talk) 23:39, 13 November 2009 (UTC)

Do you know the species ? I suppose, if you don't, you can leave them a bit of everything, from leaves to fruit to meat, and they can take what they want. Leave small enough quantities so you can tell what they take. Also leave water. StuRat (talk) 13:33, 15 November 2009 (UTC)

Different ants eat different things - from leaves (actually fungus growing on the leaf) to aphid "honey", to sugar, to meat. There is a tremendous variation. I would start by trying sugar and meat. If they like the sugar don't keep feeding them that, use something else that is sweet (like an apple). If they eat fungus from leaves you probably will not be able to feed them. If you are lucky they are omnivores, and will eat anything. Ariel. (talk) 08:11, 16 November 2009 (UTC)

bipolar disorder

i am repeating this question as i didn't get relevant answer. i would like to know percentage of global people affected by bipolar disorder and age wise distribution of this disorder globally ... pl help some one .. —Preceding unsigned comment added by Arun vvv (talk • contribs) 12:33, 15 November 2009 (UTC)

You might find some figures in some countries for the number (and ages) of diagnosed cases, but I don't think anyone has attempted the difficult task of guessing the rate of occurrence or age distribution world-wide. The condition is not easy to diagnose in an individual, so it is even more difficult to estimate global figures. Is it even recognised as a disorder in some countries? I assume that you have read our article linked in answer to your previous question. It suggests that about 1% of children and 2% of the population from teenage upwards suffer from the clinical condition, with perhaps a further 2% or more having a minor form. The condition is never considered to be "cured", so an age distribution is not appropriate. Dbfirs 13:16, 15 November 2009 (UTC)

PMID 17162652 is probably the best source of up-to-date information, if you have access to it. Looie496 (talk) 17:30, 15 November 2009 (UTC)

Thanks. Is there anywhere that someone without access can read a reasonably detailed summary? Dbfirs 23:36, 16 November 2009 (UTC)

Feeling in eyes.

Do your eyes feel heat? I assume they do but I don't think I've ever though 'man my eyes feel cold' so I'm unsure. —Preceding unsigned comment added by Jimothyjim (talk • contribs) 13:22, 15 November 2009 (UTC)

It's not your eyes, but sensory neuron on your cornea -it respond to heat and so it should also respond to loss of heat. Meaning that I guess that a hit of liquid oxygen would heart (P.S. it's not the best example as such hit would also cause to extensive damage-but there is such thing as cold pain) .--Gilisa (talk) 13:41, 15 November 2009 (UTC)

Thermoception isn't a very well developed article, but it notes correctly that hot and cold thermoreceptors in mammals are in the skin. However, some animals do have thermoreceptors in their eyes, e.g. cats have cold receptors.[1] There's evidence that humans can detect cold on the cornea and conjunctiva.[2][3] Fences&Windows 14:38, 15 November 2009 (UTC)

You've never felt cold in your eyes? I have....is that unusual? Vimescarrot (talk) 15:13, 15 November 2009 (UTC)

I'd say that most people would reflexively shut their eyelids, thus reducing the stimulus that would kick ofs a response -- sort of like people who experience less tooth pain to cold air when they shut their mouth. DRosenbach ^{(Talk | Contribs)} 15:35, 15 November 2009 (UTC)

Try the opposite - if you sit close to a fire in a fireplace, you'll get a hot headache, and can often feel the heat "behind" your eyeballs (as implied above). ~ Amory (u • t • c) 19:41, 15 November 2009 (UTC)

Certainly cold water feels cold, I think. 68.193.225.106 (talk) 15:59, 15 November 2009 (UTC)

Hmm, maybe my eyes do feel cold but I just don't notice.

Looking for the name of a knot similar to the clove hitch

I'm looking for the name of a hitch knot, which is similar to the clove hitch. In the clove hitch, a part of the rope runs diagonally, compressing other parts of the rope forming the knot. In the knot I'm talking about, there's a twist in the part of the knot under the "diagonal" section. Supposedly the knot is more secure that the clove hitch. Does anyone know the name of the knot? (Sorry if my description is not very clear.) —Preceding unsigned comment added by 173.49.12.245 (talk) 15:43, 15 November 2009 (UTC)

The constrictor knot, ground-line hitch and snuggle hitch are all similar to the clove hitch, but more secure. Are you thinking of one of those? Red Act (talk) 16:33, 15 November 2009 (UTC)

The constrictor knot was what I had in mind. Thanks. --173.49.12.245 (talk) 16:49, 15 November 2009 (UTC)

activity vs sleep on mountains

i'm not asking for medical advice here, i have no intention of climbing a mountain but i'm wondering if it's true that you need to stay awake on mountains to keep your body temperature up? i'm pretty sure that sleeping well in a safe place is just as important to get your energy back up? —Preceding unsigned comment added by 87.114.162.77 (talk) 16:22, 15 November 2009 (UTC)

If you're severely hypothermic (so cold that you've stopped shivering), then falling asleep would be bad, but at that point you'd be on the verge of dying anyway. Body temperature drops a little bit during sleep automatically, but if it drops enough to be harmful, you will start shivering and that's sure to wake you up. In my experience (never been actually hypothermic), it's impossible to fall asleep if you're shivering. I have spent a few very unpleasant nights on mountains that way. Looie496 (talk) 18:29, 15 November 2009 (UTC)

If you're in a place dangerous enough that you shouldn't sleep to avoid dying, you are already very hypothermic and in danger and should calmly and carefully get off the mountain. The first step is to always avoid a dangerous situation like that by planning ahead and being safe. You will not think clearly when severely hypothermic. You should only ever go up a mountain if you have adequate shelter and warm clothing, in which case it will often be okay to sleep. ~ Amory (u • t • c) 19:38, 15 November 2009 (UTC)

I agree with what has already been said. On a related note, however, at very high altitude (eg. Everest Camp IV) sleep apparently becomes very difficult. It's not that it is dangerous to sleep, it's just difficult to get to sleep. --Tango (talk) 21:56, 15 November 2009 (UTC)

Ah ok, maybe i misunderstood what i was told then. Stay awake if you're about to die, nice lol! Tx for hypothermia link, that explains a lot. —Preceding unsigned comment added by 87.114.162.77 (talk) 23:50, 15 November 2009 (UTC) --87.114.162.77 (talk) 23:52, 15 November 2009 (UTC)

self-serve check-outs and phone answering systems

Most of these registers are manned by one cashier to four registers. In many cases this cashier is busy with another customer when a problem happens. For this reason many people are exposed to a talking register that treats them as if they were a computer. An even worse situation of computers treating people like they were computers are telephone, bank and other business and institutional phone answering systems (USPS is one of the worst). Are such systems a threat to the civility of mankind and perhaps in part responsible for indiscriminate psycho crimes like terrorism? 71.100.2.243 (talk) 16:37, 15 November 2009 (UTC)

I don't think this is a very scientific question, and I don't have a very scientific answer. These computers you speak of do not pass the Turing test, so people can consistently tell the difference between talking to a human and dealing with one of these computers; thus, I don't think any confusion between the two contributes to violent behavior. My sense is that if people relax and focus on the task at hand, the task gets done. -- Scray (talk) 16:47, 15 November 2009 (UTC)

"Are such systems a threat to the civility of mankind and perhaps in part responsible for indiscriminate psycho crimes like terrorism?" I don't think there's any evidence that such things contribute to threats against the "civility of mankind" (whatever that means), and have seen zero evidence that such systems have any responsibility for "indiscriminate psycho crimes like terrorism". I think it would be fairly idiotic to assume without any evidence that frustration with phone answering systems has any connection to terrorism. The systems probably do contribute to a decreasing satisfaction amongst consumers with customer service (I cannot stand the phone systems and find them unhelpful; if you keep pressing the zero key, you often end up with a live person, though), but and they do have economic effects (they are used to avoid hiring live human beings), but other than that, I don't see any reason whatsoever to ascribe them much influence. --Mr.98 (talk) 17:04, 15 November 2009 (UTC)

I actually prefer the self-checkout, for these reasons:

1) I can check each price and make sure it's correct. You can try this in a traditional check-out, but the display is often aimed at the cashier, not you, and the cashier may check things so quickly that you can't keep up. In almost every load of groceries, I'm overcharged on at least one item, so missing this is expensive.

2) I can bag things properly. I put the frozen items together, the refrigerated items together, etc., while many baggers don't bother.

3) I can avoid have my food damaged by the cashier and bagger. I've had bananas slammed down, only to get bruises almost immediately, and have had a greeting card placed in the leaking milk sludge on the conveyor belt, even after I handed it directly to the cashier.

That said, they really need to work on a few problems:

A) They don't assign enough people to oversee them. Perhaps one cashier for every 2 or 3 would work. However, they need to actually keep the cashiers present. They frequently seem to walk away to do God-knows what, leaving the customers totally unattended. Maybe they can put a location sensor on the cashiers and dock them pay for every minute they are out of the area ? (Or fire them if they take it off.) There has to be some way to get them to do their jobs.

B) Many tasks require a cashier that shouldn't. If I have a coupon, I have to hand it to a cashier. If I want to cancel an item I scanned, I need a cashier. If I have an item with a hand-marked price, I need a cashier (in this case they need to stop hand-marking prices).

C) Many of the automatic check-out lanes need repair. There's some where the scale doesn't work, some where the voice part is broken, etc. They continue to use these defective lanes, which cause even more time demands on the cashiers. StuRat (talk) 18:45, 15 November 2009 (UTC)

With all of your points I agree. I usually buy canned goods in bulk and people behind me in line get perturbed whenever I start scanning individual cans. One cashier refused to override and enter the number of cans saying it was against chain policy. In another instance when my card was not approved due to faulty communication link the cashier refused to return my card until I threatened to call the police and have him charged with theft. My bank backed up my contention and he would have gone to jail. The problem I experience most is that recently there is some kind of holdup every time I use the self-checkout register. Repeatedly pressing zero usually results in the phone system hanging up.

I can't seem to find an alternate system or solution. Perhaps I can find a store that will allow me to fax, email or call ahead to place an order and have it ready for me to pick up in a couple of hours. 71.100.2.243 (talk) 20:30, 15 November 2009 (UTC)

As for the dehumanizing effects, the monotone voice is high among them, especially when it says something like "Have a good day". It just doesn't work when it comes from a machine. With a cashier you may suspect that they don't mean it, but at least it's possible that they do. And a monotone voice repeating the same thing ad infinitum actually seems even worse for the people who work there; I've seen them go to extremes to shut it up. StuRat (talk) 21:02, 15 November 2009 (UTC)

Do other people get "Unexpected item in the bagging area" every time they place an item in their bag, or is it just me? Certainly contributes to the stress level. Itsmejudith (talk) 21:19, 15 November 2009 (UTC)

I have had that problem at one particular chain of home improvement stores, but it's now been resolved. I think this reflects an important aspect of these systems - they will improve when people complain and companies listen, and the improvements scale well (compared to human training, for example). While I like to see people employed, there are some tasks that are so mindless and repetitive that machines can do the job better. Scanning groceries seems like one of those. -- Scray (talk) 21:26, 15 November 2009 (UTC)

In the case of self-check outs, a human still does the scanning, it's just now the customer. StuRat (talk) 21:53, 15 November 2009 (UTC)

Point taken - thanks for setting me straight there. I do anticipate greater automation being the next step, probably eliminating checkout aisles as we currently recognize them, but I don't want to treat the RD as a forum. -- Scray (talk) 22:30, 15 November 2009 (UTC)

Do you mean like the Quick Check system used in Waitrose? That is awesome, and does pretty much eliminate the normal checkout for everything except random rescans. And it alerts you to special offers when you scan things in, which is surprisingly useful. Doesn't quite cancel the greater expense of shopping at Waitrose, though. I can see it catching on in a lot of other shops if the initial cost comes down: remember how quickly the self-service checkouts caught on? 86.142.231.220 (talk) 23:43, 15 November 2009 (UTC)

The customer still scans there, just when they put the items in the cart instead of at checkout time. I can imagine a system that's fully automated, but not with bar codes, as those need to be pointed at a scanner to be read. The type of inventory tags they use on clothes have the ability to do a remote scan, so it's possible you could put your cart on a conveyor belt and it could go through a shielded scanner (so you don't get charged for the next customer's cart contents), and scan everything at once. I'm not sure that this would be a good thing, though, as pricing errors and unscanned items are likely to go unnoticed under such a system. StuRat (talk) 12:23, 18 November 2009 (UTC)

I think he means more like the self scan checkouts at ASDA and Tesco.  Ronhjones  ^(Talk) 00:23, 16 November 2009 (UTC)

Oh, I thought that was already covered in the previous comments. How do they include greater automation that other self checkouts? 86.142.231.220 (talk) 00:57, 16 November 2009 (UTC)

In the case of telephone companies who have perfected the technology to the greatest extent the monotone is almost gone but the resistance to turning the call over to a human operator even greater. (same for USPS who use this technology). To speak with an operator versus the system hanging up you first must provide your telephone number or account number, if its about data versus voice and if its data what your operating system is, what type of modem you have and on and on and on. An even more expensive lunch for the added speaking capability with even greater resistance to putting you in contact with a real live human including substantial wait time and failure to allow contact if your particular issue is not in its list. Try to get in touch with the right party to report a tree that is now so large it hs grown three inches around the cable or to report a thousand other problems. The menus are never well developed or based on proper classification principals. (see http://academia.wikia.com/wiki/Optimal_Classification) 71.100.7.189 (talk) 23:40, 15 November 2009 (UTC)

Automated systems have the potential to answer a few basic questions well, like their hours, location, driving directions, etc. It's when they try to use them for everything that the problems begin. Don't you just love the automated phone systems that repeatedly ask you for your all your info, including a 40 digit account number, timing out because you can't enter it quickly enough, until you eventually get it right, then they transfer you to a human who asks for all the same info again ? One trick to get hold of a human is to call the sales department, since they actually want to give the impression of having proper customer service until they get your money (then they never want to talk to you again). Of course, getting a salesman to transfer you to an actual person in the service department, instead of the infernal automated system, is another challenge: "Your call is important to us, although obviously not important enough to actually answer". StuRat (talk) 12:33, 18 November 2009 (UTC)

On the subject of self-checkouts, my local library has a system where no scanning is involved. Every book is fitted with a sticky label containing a radio tag (RFID I guess?) and the customer just plonks their stack of books onto a pad containing a sensor and it automatically checks out the lot. When this technology becomes cheap enough to put on disposable items like groceries rather than just assets with a longer life, such as library books, the "checkout rage" caused by scanning groceries will become a thing of the past, I can see having some kind of a scanner that you wheel your trolley through (like an airport security scanner) or a floor-mounted device that automatically scans your shopping and so all you have to do is pay.

Also, 'contactless' payment cards (like in that Barclaycard advert with the waterslide) may even automate that - you walk through the scanner and it deducts the value of your shopping from your contactless card. The security issues with that could be resolved by iris-recognition technology.GaryReggae (talk) 13:27, 19 November 2009 (UTC)

Rechargeable battery

How does the total life of a rechargeable battery compare with a non-rechargeable ? By "total life", I mean all the milliAmp hours you can get out of either battery until it's voltage drops permanently below the rating. In particular, I'm interested in AAA batteries, so I can decide whether rechargeables make sense in my walky talky. The rechargeables in question are Ni-MH and the non-rechargeables are "super heavy duty", which I think means "not alkaline". StuRat (talk) 18:06, 15 November 2009 (UTC)

I don't know about AAA batteries, but I did find this piece on how rechargeable vs. non-rechargeable AA batteries work for long term use in electronics. It recommends that for devices that are used often or "draw bursts of power" (such as a digital camera for taking a picture with flash), use rechargeables, and for seldom used or low power devices, such as flashlights or remote controls, use single-use batteries. Ks0stm ^(T•C•G) 18:49, 15 November 2009 (UTC)

The issue is that my price structure may well be different than theirs, since I can get permanent AAA cells in an 8-pack for a dollar, while I have to pay 20 times as much for rechargeables. So then, the question is if the rechargeables last 20 times longer. StuRat (talk) 18:57, 15 November 2009 (UTC)

Permanent AAAs aren't - that would be great ;-). The answer to your question depends not only on the battery type, but also on the application. Most rechargeables provide a fairly constant voltage (and current) until they are fairly drained, and then drop quickly towards (nearly) zero. Conventional batteries drop more evenly. If your walky talky is digital, it will need a certain minimum voltage, and you may not be able to use plain batteries to their full capacity. Also, most rechargeables can be used a lot more often than 20 times. As far as I can tell, for all items that use significant current and are in frequent use, rechargeables are the more economic choice. On the down side, they have a much quicker self-discharge rate, so they are unsuitable for storage or items like an alarm clock, that runs for years on a plain battery. ---Stephan Schulz (talk) 20:48, 15 November 2009 (UTC)

You seem to have assumed that both types of battery last just as long on the initial charge. I don't agree. I think rechargeables discharge faster, especially when old, but I don't know by how much. StuRat (talk) 21:06, 15 November 2009 (UTC)

No, I did not assume such. Yes, older rechargeables eventually loose capacity. As for initial capacity, look at List of battery sizes, which indicates non-rechargeables have between 50% and 20% higher initial rated capacity. But, since rechargeables hold voltage longer, they will discharge faster over the same resistance than non-rechargeables. Of course, they will typically also give higher performance. Anyways, due to the fact that they have much more than 20 recharge cycles, my point stands. --Stephan Schulz (talk) 22:05, 15 November 2009 (UTC)

The reason rechargeables are not good for slow draws, or infrequent uses is that they self discharge, and most will not last more than a month or two. Regular batteries don't self discharge (as much), because they have a higher internal resistance - but that internal resistance means that can not support a high draw without wasting energy. So it's a balancing act: do you want high power, low shelf life, or low power, long shelf life. PS. I don't think anyone makes low power long shelf life rechargables because it doesn't make sense from an economic point of view - why pay so much for a battery to sit and do nothing? Ariel. (talk) 08:06, 16 November 2009 (UTC)

The "super heavy duty" cells are zinc chloride battery and they are near useless at high current drains, which would include walkie-talkies in transmit mode. Rechargeables are much better for that. One problem with rechargeables was an "arms race" between NiMH battery manufacturers in the 1990's to make cells of higher and higher capacity, by making the insulating layer inside the cell thinner and thinner until the cells became unreliable (they lose the ability to hold a charge soon after you buy them). The cure is to buy pre-charged cells (low self-discharge NiMH battery). They have slightly lower capacity but the advertised advantage for them is they mostly eliminate the self-discharge effect (which they do), making it possible to ship them pre-charged and have them retain their charge on the retail shelf. I don't have an RS for it but I've seen stated in several places that what they basically did was go back to a thicker insulating layer, which not only gets rid of self-discharge but also makes the cells more reliable. I've been using these cells for a few years and have had very good results from them, unlike the max-capacity ones I used earlier which crapped out all the time. 69.228.171.150 (talk) 21:47, 16 November 2009 (UTC)

Thanks for the replies so far. I leave my walkie-talkies in the charger most of the time, but occasionally leave one out all night, and it then dies if I try to use it. I assume this is the ugly self-discharge problem. I will investigate the "pre-charged rechargeable" batteries as an alternative. StuRat (talk) 01:26, 18 November 2009 (UTC)

Human Scent

I had asked a previous question about human scent, but didn't find the answer to one part: Why can people not smell their own scent? Is there any way to make this possible? Thanks in advance... Ks0stm ^(T•C•G) 18:39, 15 November 2009 (UTC)

I suppose if anybody was in any way 'cut off' from their own scent, either by intensively using deodorant or perfume or by some mechanical means (i. e. carrying a clothes pin on your nose for a year, or any other nasty way), then I suppose after the foreign means had been removed one could become conscious of their own smell. IMHO. --Ouro (blah blah) 18:48, 15 November 2009 (UTC)

I think people can. You may get accustomed to any smell you are exposed to continuously, though, so may need a higher concentration to detect it. So, if you run a marathon and sniff your pits, I bet you will smell something. StuRat (talk) 18:51, 15 November 2009 (UTC)

It's called habituation, but when one raise his hand to enjoy the wonderful aroma of his armpit, just after intensive training in a gym, then he can smell himself very well. But if you leave him in a room filled with this odor for one-two hours, it would be more than enough to make it imperceivable. The first to describe the molecular mechanism for it (in Aplysia) was Eric Kandel and along with other studies he performed, his studies on the Aplysia's habituation mechanism actually founded the modern study of memory processes. Much more interesting thing happen when people try to tickle themselves, here-in different from habituation, the brain 'predicts' the action and it knows what areas exactly are going to be tickled, so it won't have any effect.--Gilisa (talk) 19:51, 15 November 2009 (UTC)

Everything Gilisa posted applies to females too. "Horses sweat, men perspire, women glow". Cuddlyable3 (talk) 21:46, 16 November 2009 (UTC)

a purely conceptual thought experiment

In a purely conceptual thought experiment I have discovered the CONTIUM.

The CONTIUM is simply a neutron, which instead of becoming a proton and electron or Hydrogen-1 becomes a CONTRON and a positron (a positively charged electron ).

The significance of this discovery is that external energy is no longer required to overcome the Coulomb barrier. In fact there is no Coulomb barrier.

The only way to keep Protium and Contium apart is with a polar magnetic field strong enough to do the job. When the field collapses the Protium and Contium are attracted.

My question is do they annihilate each other or do they undergo fusion and if fusion what are the most likely byproducts? 71.100.2.243 (talk) 19:22, 15 November 2009 (UTC)

Anything could happen since it's particles that dosn't exist in reality, but you may want to define their anti-particles and invoke CPT symmetry to run the reactions in reverse. It's a common line of reasoning in particle physics. EverGreg (talk) 19:29, 15 November 2009 (UTC)

We do not speculate about hypothetical things on the reference desk; and we do not encourage publication of original research - Wikipedia is an encyclopedia, not a forum for new ideas. A quick search shows that "contium" or "contron" do not appear in any prior scientific literature. Nimur (talk) 03:03, 16 November 2009 (UTC)

I understand the overpowering fear of academics being wrong and forever having that label on their coattail so let me put the question so you can provide a known answer. What force other than temperature and pressure can overcome the Coulomb barrier? 71.100.7.189 (talk) 05:25, 16 November 2009 (UTC)

Neither temperature nor pressure are a force. The coulomb barrier is a potential energy "barrier". Your use of terminology in this question is not valid, so there's no way to answer it as you have asked it. Nimur (talk) 06:38, 16 November 2009 (UTC)

All forces can "overcome the Coulomb barrier". As for Contium - if you started with a neutron (no charge), and split into a positron (positive charge), and "something" (contium), that something *MUST* has a negative charge, otherwise you violate Conservation of charge. Your "Contium" sounds very much like an anti-proton. If a proton (AKA protium) and an anti-proton annihilate each other a gamma ray will issue. Ariel. (talk) 07:59, 16 November 2009 (UTC)

Keeping the discussion factual, if the contium is basically a neutron, it will have baryon number 1. This means it must decay into a total baryon number of 1, so the contron must have a baryon number of 1. Intrincially, it has lepton number 0, so unless something very strange is happening, lepton conservation is broken. This can be solved with a(n) (electron) neutrino, but you then get n → c- + e+ + νe. Which is very like p+ → n0 + e+ + νe (merged with n0 → p+ + e− + _νe) , except not so explainable. Basically, your particle breaks known rules, or this universe. If you wish to imagine a completely different universe, fine, but you can't carry it accross to here, at least by my reckoning. - Jarry1250 ^{[Humorous? Discuss.]} 18:09, 16 November 2009 (UTC)

Type 1 Diabeetes - Sugar allowed in a can of drink

Really obscure question here, but does anyone know how muc h sugar people with Type 1 diabetees are 'allowed' to have in a can of drink? It's kind of a weird question but I'm asking for a friend :S —Preceding unsigned comment added by 82.11.245.145 (talk) 19:35, 15 November 2009 (UTC)

There is no such allowance. The source of the sugar is largely irrelevant. The amount of sugar they can have will depend on the nature of their condition (everyone is slightly different) and how much insulin they have had/will have. --Tango (talk) 19:45, 15 November 2009 (UTC)

Okay well, let me rephrase, roughly how many grams of sugar do you reckon an average type 1 diabeetes person could have in a drink without it affecting their sugar level? 82.11.245.145 (talk) 19:54, 15 November 2009 (UTC)

This is massively getting into the realm of medical advice, which we aren't allowed to give here. Suffice it to say that even for an "average" type-1 diabetic, if there was such a thing, the amount of sugar they could safely drink in a can would depend on a huge number of factors and there's no number we could give you that would be particularly meaningful without detailed knowledge of the specific situation. ~ mazca ^talk 20:13, 15 November 2009 (UTC)

This is purely hypothetical, nobodys drinking any cans of coke based on the advice here :P Also I don't mean safely, I mean literally no change in their levels, not even a safe change, just no change. Jimothyjim (talk) 20:22, 15 November 2009 (UTC)

None at all, then. Any consumption of sugar will raise blood sugar levels temporarily, in a diabetic or otherwise. --Tango (talk) 21:02, 15 November 2009 (UTC)

Okay, thanks all, I think everythings all sorted out now. More confusion over the question than anything. Jimothyjim (talk) 21:08, 15 November 2009 (UTC)

Here's a link from the American Diabetes Association that might be helpful.Sjö (talk) 12:54, 17 November 2009 (UTC)

Your assumptions are too vague to give you a precise answer, but many of the responses are misinformed as well. What does "allowed" mean? The major difference between the harm of a can of soda to a person with type 1 DM and the harm to you is simply that the person with T1DM needs to take insulin to metabolize the glucose while you make your own insulin. A typical ratio of insulin to carbohydrate needed by a young adult with T1DM is about 1 unit per 10 g of carb (there is wide variation among individuals). If the person takes the correct amount of insulin there is likely no apparent difference between the harm the soda does to him and the harm it does to you. If the person with diabetes does not take the extra insulin then his sugar goes high for a few hours, usually with no discernible immediate consequences, but perhaps contributing in a small way to long-term blood vessel damage. If you drink a soda there are likely no discernible immediate negative consequences but there may still be subtle long-term harm to you in many ways (obesity, bone damage, replacing needed nutrients, perverting your taste and altering your satiety settings, raising your uric acid, etc). alteripse (talk) 13:44, 17 November 2009 (UTC)

This is a medical question.174.3.102.6 (talk) 01:36, 20 November 2009 (UTC)

Good pickup. That's why a doctor is providing the best answer. alteripse (talk) 02:38, 20 November 2009 (UTC)

Toxicity of hydrogen peroxide

In Charlie Chaplin's film Monsieur Verdoux, Chaplin's character thinks he's pouring poison disguised as hydrogen peroxide into a bottle of red wine, but instead, he's pouring real hydrogen peroxide into the wine. He and his lady friend later drink the wine, and suffer no ill effects, save for inebriation. Is hydrogen peroxide actually toxic? Does it have any harmful effects when ingested in such small quantities (only a few centilitres)? JIP | Talk 20:27, 15 November 2009 (UTC)

One of the uses of the common 3% hydrogen peroxide solution is as a gargle, so presumably it's not very toxic. 100% hydrogen peroxide would burn you severly, on the other hand. StuRat (talk) 20:45, 15 November 2009 (UTC)

A 100% solution is hard to get and even harder to store for a long time. The most important thing is the concentration 3% or 30%. Wine has some imputities which will slowly oxidize and the hydrogen peroxide vanishes away. The small particles will also catalyze the decomposition of hydrogen peroxide. --Stone (talk) 20:51, 15 November 2009 (UTC)

Hydrogen Peroxide is most definatly not good to drink in large quantities or concentrations; which is why you gargle it. 3% solutions are generally recognized as safe, but I would still read and heed Hydrogen_peroxide#Safety. Wine may contain some measurable amount of Catalase, which would basically turn the red wine/hydrogen peroxide into Cold Duck... --Jayron32 05:45, 16 November 2009 (UTC)

Heteroaromatic Chemistry Problem

I can see from experimental results that the chlorine in 2-chloropyridine is easily displaced by nucleophiles such as amines. However, this isn't the case with 3-chloropyridine....why?! 188.221.55.165 (talk) 22:44, 15 November 2009 (UTC)

this article outside of Wikipedia explains in some detail the mechanisms of such reactions on pyridine, with electron pushing diagrams. See also Chichibabin reaction. --Jayron32 05:38, 16 November 2009 (UTC)

discoloration in schitzu's hair

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.

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 or 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. --~~~~

) 188.221.55.165 (talk) 23:49, 15 November 2009 (UTC)

Discoloration of a dog's fur is "medical advice" ? That's quite a stretch. StuRat (talk) 23:37, 17 November 2009 (UTC)

Dicussion is here: [4]. StuRat (talk) 23:43, 17 November 2009 (UTC)