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April 3

SINUS OF NOSE

1. Whats the known cure for sinus? —Preceding unsigned comment added by KENNEDY NEWTON (talk • contribs) 01:25, 3 April 2010 (UTC)

The Paranasal sinuses are the large spaces between your nose and your throat. They aren't cured because they are not a sickness or disease. They are just big cavaties inside of your skull. Sinusitis is a situation when your sinuses become inflammed when you have a cold or have allergies like hayfever. Wikipedia is not the place to go for medical advice. You are free to read our articles about these topics, but if you are having sinus problems, see a doctor in person. They can help you. --Jayron32 01:40, 3 April 2010 (UTC)

Baseball physics

Hey all. My bio prof said something the other day that I think wasn't quite right. Consider a baseball. If it has a velocity of 90 miles/hour west, and it was hit by a bat with 100 mph (east), how fast (east) would the ball move? The prof said 190mph, but how could it be greater than either speed? THX 76.230.145.252 (talk) 01:44, 3 April 2010 (UTC)

The reason is is because the heavy bat has a lot of energy swinging (as anyone who has been hit by one can tell you). When the heavy bat hits the relatively light ball, all the energy it took to move a heavy bat at 100 mph now goes into a ball that weighs a few ounces. It takes less energy to move the ball than the bat, so when the ball receives the same amount of energy that it took to move the bat, it goes much faster. --The High Fin Sperm Whale 01:49, 3 April 2010 (UTC)

This is how to think of it. If we assume that the bat and ball are part of an elastic collision (read that article), it means that the energy is conserved in the objects colliding. Certainly, a small amount of energy is lost (sound and heat mostly), but its not a bad approximation. If the energy of the ball-bat system is roughly the same before and after the collision, then almost all of that energy is part of the combined system is transfered to the ball. I'm not sure where the 190 mph comes from; energy should be additive, and not velocity, but yes, the ball SHOULD be moving faster by itself than either was moving before the collision. Since we assume elasticity, then the direction doesn't matter; energy can reflect and change direction just fine. --Jayron32 02:04, 3 April 2010 (UTC)

Both bat and ball have a little elasticity - so that much of the kinetic energy from the westbound motion of ball goes into bending the bat and deforming the ball. As the ball heads off in the opposite direction, both bat and ball un-deform - giving back much of that energy. Hence, the ball can leave the surface of the bat and get that extra 'kick' at the end. SteveBaker (talk) 02:05, 3 April 2010 (UTC)

Ok, I know that the ball is moving faster after the collision, even if only due to the difference in energy the ball has and the bat has. But where did my prof get 190? It seems like an arbitrary mathematical operation. If we set values for the masses of the ball and bat (let's call them x and y, respectively) how would we figure out how fast the ball was actually going after the collision? 76.230.145.252 (talk) 02:13, 3 April 2010 (UTC)

I'm assuming he simply added the 90 mph from the ball and the 100 mph from the bat, and got 190 mph (90 + 100). In general, you can't add velocities. While issues of special relativity only show up at really high speeds, you still can't do it at low speeds, because velocity is not the conserved quantity, momentum and energy are. (Even if velocity was conserved, it wouldn't be 190mph, as the bat still has forward motion after it contacts the ball.) I was going to mention the Galilean cannon as a cool demonstration that velocities are not conserved, but I can't seem to find reference on Google to the usage. As I recall it, it's a stack of steel spheres of increasing size dropped down a tube. When they hit the bottom, the smallest (top) sphere get almost all of the momentum from the stack (as in Newton's cradle) and goes shooting off. Is this actually called something else? -- 174.31.194.126 (talk) 02:42, 3 April 2010 (UTC)

I agree. The 190 mph does seem a bit random. It doesn't seem to have any basis in real calculations. What you would need to know is the speed of the bat, the mass of the bat, the speed and mass of the ball, and the amount of time they are in contact with each other in order to calculate how much energy is likely transfered to the ball. It would only be by a bizare coincidence if the ball leaves at exactly the sum of their velocities. You can do a simple experiment to show that velocity is not additive in this way. --Jayron32 02:29, 3 April 2010 (UTC)

Jayron, the contact time is neither necessary nor very useful. The coefficient of restitution is the extra piece of information required to solve that kind of problem. Dauto (talk) 02:54, 3 April 2010 (UTC)

This study takes into consideration bat speed, weight and coefficient of restitution. caknuck _° needs to be running more often 03:17, 3 April 2010 (UTC)

(edit conflict) Assuming an elastic collision, and ignoring the effect of the person swinging the bat, then the ball, from the reference frame of the center of mass, appears to enter and leave at the same speed before and after the collision (momentum and energy are conserved). If we approximate the bat as infinitely massive (or significantly large compared to the ball), then the center of mass reference frame is just the reference frame of the bat. In that case, the ball, from the bat's point of view, enters at 190 mph, and so must leave at 190 mph. Adding that to the bat's 100 mph, we get the ball traveling 290 mph in the stadium reference frame. That's obviously not a good answer (the collision's not elastic, the bat's not infinitely massive, etc.), but the 190 seems to come from nowhere as well. Buddy431 (talk) 03:30, 3 April 2010 (UTC)

Assuming the (lets say ~35 ounces (0.99 kg)) bat loses 10 m/s its velocity of 100 miles per hour (45 m/s) through the collision with the .145 kilograms (5.1 oz) baseball traveling at 90 miles per hour (40 m/s), then:

$.145\times -40+.99\times 45=.145\times X+.99\times 35$

$-5.8+44.55=.145X+34.65$

$4.1=.145X$

28.28 metres per second (63.3 mph) = the ball's final velocity? I think I need more help than the professor...what'd I do wrong here? If no one corrects this by morning, I'll get out my physics book and redo this. Ks0stm ^(T•C•G) 05:22, 3 April 2010 (UTC)

Why would you assume that? Dauto (talk) 06:44, 3 April 2010 (UTC)

The "Astro-blaster" is the modern version of theGalilean cannon that '174 mentioned above (which - surprisingly - isn't named after Galileo - but after the city of Galilee). I guess the original has a stack of balls inside a tube - the modern version has four balls threaded on a wire. Ranging from a large/heavy one at the bottom through consecutively smaller and lighter balls to a small one at the top. You drop this contraption so that the big ball hits the ground and the topmost ball will rebound with a spectacular amount of speed. So much so at they have to sell the gizmo with safety goggles! An even simpler way to demonstrate that "conservation of momentum" most certainly doesn't mean "conservation of velocity" is demonstrated in this YouTube video - which is essentially a Galilean cannon with just two balls. It's hard to believe that we don't have an article about this stuff - but it's tough to find details for anything other than the modern version. SteveBaker (talk) 16:35, 3 April 2010 (UTC)

(I created a Galilean cannon article...it could use some expansion). SteveBaker (talk) 03:07, 4 April 2010 (UTC)

Your 3rd ref just seems to be floating out in space. StuRat (talk) 03:13, 4 April 2010 (UTC)

Can I ask an unrelated question here? It may not be completely unrelated. Let us say a baseball is pitched fast — a fastball. Let us say a batter hits a powerful line drive off the fastball, almost directly back at the pitcher — let's say several feet over the pitcher's head. It is a very powerful shot and it is an out-of-the-park home-run. My question is: Is the ball ever at rest between making contact with the bat and sailing off over the pitcher's head? To phrase it differently: Does the ball's motion in one direction involve coming to a complete stop before embarking on its motion in virtually the opposite direction? Bus stop (talk) 03:30, 4 April 2010 (UTC)

This is a version of the fly-and-train paradox (it probably has a better name - but I don't know what it is). The idea is that there is a teeny-tiny housefly heading east along a railroad track which hits a train heading west. Since it seems obvious that there must be a moment when the fly goes from travelling at 10mph to the east to moving at 60mph to the west, there must be some moment at which the fly is stationary...but since it's in contact with the front of the train - then surely the train is also stationary at that moment! Why doesn't train react to hitting the fly in the same way it would if it hit a 500 ton, stationary, solid steel barrier?

The reason this isn't true (and the reason why we wouldn't say that the baseball was ever strictly speaking, "stationary") is because neither flies nor locomotives nor bats nor baseballs are perfectly rigid. So the object doesn't reverse direction instantaneously as a solid lump - it does it atom by atom. So it's perfectly possible for individual atoms to slow down, stop and the reverse direction without the entire object seeming to do so. At the necessary low level of visualisation, everything is very elastic and bendy. SteveBaker (talk) 04:14, 4 April 2010 (UTC)

Thank you for that response. Let me try to pose another question (or two). I'm not sure this question makes sense, but here goes:

If two atoms, or subatomic particles, collide, head-on, both of which are traveling in exactly opposite directions, both of which are of equal mass — how do they behave in ways relating to the collision? Do either or both of them reverse direction? Do either or both of them spend a duration of time at rest before resuming travel? Bus stop (talk) 11:03, 4 April 2010 (UTC)

At the atomic level, Quantum theory dominates what's going on and the simplistic ideas we have about large-scale objects like trains a baseball bats become fuzzy and uncertain. In particular, once you invoke quantum theory, it is meaningless to talk about a particle having both an exact position and an exact momentum because of the Uncertainty principle. Hence you cannot ask whether two atoms "collided" (meaning that their positions are known to be adjacent) and also know what their speed is. If you wish to talk about whether the atoms are stationary or not - then you can't talk meaningfully about their positions. At this level, atoms are fuzzy probability clouds that can't be pinned down enough for this question to even have meaning! This is an annoying final resolution to an interesting paradox - but that is how the universe works. SteveBaker (talk) 17:00, 4 April 2010 (UTC)

Surely a small amount of energy is also lost to the bat, batter and ground as vibrational energy, and some should also be lost from the ball as thermal energy due to the elastic friction and expansion of the ball during and after collision? And let's not forget about air resistance (and why is your biology prof teaching baseball physics?). ~AH1^(TCU) 23:18, 4 April 2010 (UTC)

Psychological reaction

What is the name of that feeling that one gets when their worst fears or suspicions are (actually, seemingly, or falsely assumed to be) realised? Thanks. ~AH1^(TCU) 02:26, 3 April 2010 (UTC)

Life. --Jayron32 02:29, 3 April 2010 (UTC)

A self-fulfilling prophecy ? StuRat (talk) 02:57, 3 April 2010 (UTC)

Dread seems about right to me. --Anonymous, 04:09 UTC, April 3, 2010.

Horror and terror seem close, as does fear itself at the resulting situation, and fight or flight response would be the associated physiological response. Ks0stm ^(T•C•G) 04:26, 3 April 2010 (UTC)

A sinking feeling? --TammyMoet (talk) 10:28, 3 April 2010 (UTC)

Concurred! Vranak (talk) 12:05, 3 April 2010 (UTC)

Astonishment.

As an example of this I find this line by E. Annie Proulx:

"She fought her way forward, seven, eight feet, her heart hammering, so intent on reaching the other side of the gully she felt only astonishment when the fatal aneurism halted her journey."

That is from Postcards (novel). Bus stop (talk) 03:40, 4 April 2010 (UTC)

RGB color ranges for human skin, nails, hair, and eyes

Please see RGB color range for human skin and the next three questions at Wikipedia:Reference desk/Computing.
-- Wavelength (talk) 06:02, 3 April 2010 (UTC)

I already have. And on the Humanities desk. Why do you think it necessary to post to so many reference desks? --Phil Holmes (talk) 11:59, 3 April 2010 (UTC)

Body aches and massage

It is commonly seen and experienced that general body aches and soreness feel better with simple massage. How does massage help with body aches and general soreness? Shivashree (talk) 07:11, 3 April 2010 (UTC)

When I trained as a masseuse, I was told it is partly due to the increased blood flow to the tissues brought about by the movements of the hands on the body, which breaks down things such as lactic acid and makes it easier for the blood to carry it away. It's also partly due to the relaxing effect of repetitive movements on the muscles and on the brain, and this relaxation restores equilibrium in the affected tissue. The heat generated by the friction of the massage will also relax the body. All this will stimulate the production of endorphins which are natural painkillers, and also produce a degree of euphoria. --TammyMoet (talk) 08:08, 3 April 2010 (UTC)

Plus, we are still monkeys, and grooming has its pleasures. --Ludwigs2 16:34, 3 April 2010 (UTC)

I was thinking of saying something like that but didn't bother, but you put it more succintly anyway. Of course it's unclear how much this will apply if we're referring to something like a massage chair with no other human involvement Nil Einne (talk) 17:26, 3 April 2010 (UTC)

well, massage chairs don't work nearly as well. it's something in the physical contact with others, I think. interestingly, in orangutans (or is it gibbons, I forget), the lead male in a troop is significantly larger and has a noticeably different coloration than beta males, and both the size and coloration differences have been traced to the fact that alpha males get much more grooming attention from females. It is not an insignificant behavior. --Ludwigs2 17:55, 3 April 2010 (UTC)

I think that the nerves that transmit pain, and touch are the same nerves. If you use the nerves to transmit touch they can't transmit pain at the same time, so you don't feel the pain. This is why rubbing a "boo boo" works so well for kids. Massage presumably does the same thing, but in deeper tissues. I think that once the pain sensation stops it doesn't start up again right away, or maybe the nerves get "exhausted" and don't transmit for a while. Ariel. (talk) 01:14, 4 April 2010 (UTC)

Oh, thanks everyone, especially TammyMoet for your answers. Shivashree (talk) 04:04, 5 April 2010 (UTC)

Cute animals with bad attitudes

Can anyone provide me with some examples of animals which appear cute to humans but in reality have an extremely bad-tempered and violent nature? An encounter with someone's small, fluffy but hateful (even the owner agrees) little lap-dog yesterday got me thinking about this. --95.148.105.52 (talk) 08:17, 3 April 2010 (UTC)

If you want your living room rearranged, perhaps you can try these cute ones. DVdm (talk) 09:32, 3 April 2010 (UTC)

Wolverines could be cute. Staecker (talk) 11:44, 3 April 2010 (UTC)

Monkeys are often very cute and can be extremely violent, especially when they are protecting young. The Barbary Macaque (sometimes called "Barbary Ape", but it isn't an ape) springs to mind - they are known for ripping cars apart when they are driven through nature reserves. --Tango (talk) 11:46, 3 April 2010 (UTC)

Squirrels all seem to have bad attitudes, from the way they retreat up a tree, then "yell" at you. StuRat (talk) 11:48, 3 April 2010 (UTC)

If you've ever tried to give a kitty a worming pill you will know just how evil cute kittens can be! [1] --TammyMoet (talk) 12:11, 3 April 2010 (UTC)

Presumably one tries to force the pill down its throat? Not undue grounds for retaliation methinks! Vranak (talk) 15:01, 3 April 2010 (UTC)

Giant pandas are apparently a lot less cuddly than they look. For an extremely scientific take on this, here's a brief scene of one kicking Wolverine's ass. Matt Deres (talk) 12:49, 3 April 2010 (UTC)

Raccoons are considered by some to be adorable, but they are 'savage' when cornered. That's from a 1970s Encyclopedia Brittanica account I read. Vranak (talk) 14:59, 3 April 2010 (UTC)

Meerkats come to mind. Lovely looking, eviiiiiiiil things. Regards, --—Cyclonenim | Chat  15:46, 3 April 2010 (UTC)

I've heard that even koalas can be rather testy at times. Deor (talk) 16:48, 3 April 2010 (UTC)

Depending on your definition of "cute" the hippopotamus might fit, but they are notorious for being territorial and dangerous. They may look docile, they're considered to be the most dangerous animals in Africa [2]. -- 174.31.194.126 (talk) 18:31, 3 April 2010 (UTC)

The Peach-faced Lovebird is a cute, fluffy little bird with large, soulful eyes, a legendary reputation for affection - and quite often a very short temper, backed up by a powerful bite (for its size). --Kurt Shaped Box (talk) 19:59, 3 April 2010 (UTC)

Captive Chimpanzees are notorious for "going bad". Cute baby chimps grow into terriotorial and mean-tempered adults that can tear your arms off of your body. Bad times. --Jayron32 21:09, 3 April 2010 (UTC)

The Red-fan Parrot (Deroptyus accipitrinus) looks amazing, but has an extreme temper. I heard of someone who walked into its cage and was attacked, and has to get stitches in his hand and lip. --The High Fin Sperm Whale 00:59, 4 April 2010 (UTC)

Cute but...

Oh, and let's not forget our most cute little polar bear. DVdm (talk) 09:21, 4 April 2010 (UTC)

It depends on how you define cute, but don't forget about dolphins and hippopotamuses which can be dangerous at times. And if you don't mind a slightly alarmist and doomsday-ish source: meow. ~AH1^(TCU) 22:42, 4 April 2010 (UTC)

Owls [3] 213.122.24.166 (talk) 07:30, 5 April 2010 (UTC)

Based on the above, I'm going to say: Anything wild is called "wild" for a reason. They may not be "bad tempered" or "violent" by nature, but when cornered they are likely to do nasty things (or as nasty as their size and natural strength and weaponry allows) to the person cornering them. Doesn't make them nasty or evil by nature, it just means they've learned that humans are dangerous and should be avoided at all costs. Not an unreasonable position to be honest.

As for domesticated animals, they tend to be naturally more friendly. But that doesn't mean you won't run into individual specimens with mental disorders (small dogs in particular, and certain purebreeds tend to exhibit these; they're more inbred than any backwoods or royal family on the planet). Similarly, just like humans they can be traumatized in one way or another, or just plain neurotic. Rottweilers are naturally very sweet (about as naturally dangerous as a black lab), but because they have powerful jaws and lots of muscle, people train them to be vicious, and their natural build makes them good at it. Some animals aren't intending to be vicious at all, but make mistakes. Lots of herding dogs can be very dangerous around small children; they don't intend to harm them, but the size of a child makes the animal categorize them the same as sheep. Problem is, sheep have wool and thick hides, children don't, so the "harmless" nip of a herding dog trying to "corral" children can cause injuries. And while I love cats, I suspect that even domesticated cats tend to categorize the world into two categories: Things bigger than themselves, and prey/toys. Cats are vicious little buggers, but only to things smaller than themselves. Does that make them "bad tempered" or "violent"? —ShadowRanger ^(talk|stalk) 16:00, 5 April 2010 (UTC)

Cats seem to have figured out how to survive, but those small dogs that attack anything, regardless of size, sure wouldn't live long in the wild. StuRat (talk) 18:35, 6 April 2010 (UTC)

Grey bamboo lemurs (Hapalemur griseus) are notoriously bad tempered compared to other lemurs on average. 152.16.15.144 (talk) 19:44, 5 April 2010 (UTC)

Electrical power into food in post-holocaust conditions?

Supposing someone in a small home or underground bunker had an unlimited source of electrical power,for example an atomic or renewable power source. Assuming some catastrophe occurred such as meteorite impact, atomic war or 28 Days Later zombies making going outside hazardous, what crops could be grown inside on racks for lets say 5 years using artificial lighting, hydroponics and total water/waste recycling to sustain a person without nutritional deficiencies? Or would it be practical at all in a small space?[Trevor Loughlin]80.1.80.25 (talk) 13:18, 3 April 2010 (UTC)

Read Biosphere 2 - an actual attempt to do something exactly like that (hint: It didn't work!). Even with futuristic technology, you'd need some really fancy chemistry. You can (in theory) use power to push chemical reactions 'uphill' to make compounds with enough energy to be useful foods (sugars, etc) - but humans need protein - and that's really complicated stuff to make artificially. So you're back to using energy to grow plants and that requires light, and water and CO2 - plus some more tricky nutrients like calcium - and you'd need a large amount of space - perhaps an acre per person. Light you could provide - water, you could recycle, CO2 you'd get from your own breath. The problem would be keeping everything in balance. Every drop of water would have be reclaimed - not just urine - but also sweat, tears, moisture in your breath. You'd have to carefully reclaim every ounce of unused plant material - all of your dead skin cells - if someone dies, their body has to be recycled. This is a monumentally difficult problem. When you see how badly things went wrong with "Biosphere 2" in much less than 2 years - you'll perhaps understand why this is so tough. The best chance your survivors have is to have a BIG pile of MREs and good water and air recycling - with enough air and water in reserve to cope with the inevitable losses over time. Even then - it's tough. SteveBaker (talk) 13:53, 3 April 2010 (UTC)

(edit conflict with below) Surely you can vent waste gasses to and draw air from the outside (filtering it, of course, for radioactive fallout, etc.) and water from a well (again, with appropriate purification), so that you don't need to be quite as careful with reclamation. It's still hard to grow enough food of course, but you wouldn't suffer the CO2 and O2 problems that biosphere 2 did. I'm not sure what types of crops are best for that type of thing. Presumably some sort of legume and grain for protein, and then some high calorie starchy food (potatoes, maybe?). Like Steve said, getting all the micronutrients would be hard, but it wouldn't be too hard to stockpile multivitamins for people to consume for 10 years or whatever (and takes considerably less space than enough MREs for everyone). Buddy431 (talk) 14:55, 3 April 2010 (UTC)

The failure of Biosphere 2 doesn't really tell you a whole lot. Much more sophisticated systems have been developed since then, and since the purpose is typically for space travel, they've been done in much smaller volumes. Plants can be tiered vertically and supplying them with adequate light isn't a huge problem. With the right mix of plant foods ,protein is not a problem. You said 5 years, so we can neglect recycling dead humans. That's not to say that there aren't daunting technical problems, especially if you want a totally closed system. My semi-informed view is this is totally possible with present day technology, but it is not easily do-it -yourself (although DIYers surprise us all the time). ike9898 (talk) 14:47, 3 April 2010 (UTC)

I'm also curious about what can be done with unlimited power. If you have connected into an outside wall a Super Special Outlet, from whcih you can draw any number of amps over any voltage (you specify the voltage with a separate connected keypad first), for example, you can set the voltage to the voltage of tension wires - our article says: "In electric power transmission engineering, high voltage is usually considered any voltage over approximately 35,000 volts". Obviously you have to be careful if you go from 35,000 volts to, say, 350,000 volts, as that potential difference could just arc across dry air. But say you could design a safe way to have a 10,000,000-watt "connector", and you were able to draw any number of amps over it, let's say you decide to draw 10,000 amps, giving you... 10,000 gigawatts. What could you do with that? Going further, apparently "the Sun pumps about 386 billion million gigawatts into space", so, if you were to have available all that energy (ie "386 thousand million million" or 386,000,000,000,000,000 Gigawatts), what could you do with it? How about, if, through some means (obviously we've long since stopped talking about a single power outlet, but a limitles array of them) you had access to all of the energy not just from one star but from every star, increasing the above number by a factor of 10^24, ie the above number * 1,000,000,000,000,000,000,000,000. If there is something your above 386,000,000,000,000,000 Gigawatts weren't enough for, surely 386,000,000,000,000,000,000,000,000,000,000,000,000,000 Gigawatts would be more than enough. So, in practical terms, what could you do with all that power? For example, could you even make a Star Trek style teleporter, or food replicator? (Recalling that, by any measure, they had access to FAR less than that amount of technology). Could you magically start producing enormous power of calculation, without having to build something special for it? What else interesting could you do? 84.153.209.78 (talk) 14:08, 3 April 2010 (UTC)

That Question's already been discussed, here. 80.1 is indicating a large, but not truly unlimited power source to be used for day to day living and growing crops. Buddy431 (talk) 14:45, 3 April 2010 (UTC)

... and having more than a few kilowatts available would not be an advantage in a small bunker because it would be impossible to get rid of the waste heat inevitable in any use of power. Dbfirs 20:15, 3 April 2010 (UTC)

Recycling symbol?

This guy? He's the International Tidy Man

I noticed that on one of my things there's no recyling symbol (as arrows), but an iconic man throwing a piece of paper to bin. What does this symbol mean? 83.31.117.108 (talk) 14:31, 3 April 2010 (UTC)

I think that symbol means, 'please don't litter'. ike9898 (talk) 14:48, 3 April 2010 (UTC)

'please don't litter'? Are you sure? 83.31.103.127 (talk) 18:09, 3 April 2010 (UTC)

If it's not "please don't litter" it could be "dispose this item properly." WHat is the item? — Ƶ§œš¹ _{[aɪm ˈfɹ̠ˤʷɛ̃ɾ̃ˡi]} 21:39, 3 April 2010 (UTC)

Cat's food. [4] The top is made of metal, while the rest is plastic, I think. 83.31.103.127 (talk) 22:05, 3 April 2010 (UTC)

I would assume that the manufacturer doesn't believe that the item can be recycled and therefore is prompting you to throw the container away instead of littering. I have no idea why it wouldn't be recyclable though. Dismas|^(talk) 00:26, 4 April 2010 (UTC)

That's a pity. My cat eats around 3 a day, so I thought I could put these to the recycling bin. 83.31.93.6 (talk) 10:52, 4 April 2010 (UTC)

If you're talking about the pouches, apparently they're a sort of amalgam of plastic and a metallic substance, which is currently unrecyclable. (This is what I was told by the recycling department of our local UK council, anyway) --TammyMoet (talk) 14:10, 4 April 2010 (UTC)

I think the OP is referring to something like this [5] (yes I appreciate this is dog food but Sheba who evidentally were the cat food equivalent don't exist anymore) or [6] (left not right). I did come across [7] which may be of interest Nil Einne (talk) 15:31, 4 April 2010 (UTC)

Yep, I mean these [8] What is funny, I had bought my cat similar food but of another brand/manufacturer, and found on the bottom of the package this symbol. 83.31.118.222 (talk) 15:43, 4 April 2010 (UTC)

A quick search on Google Images tells me that the sign means "Keep this area litter free", but that it isn't very widely used. Looie496 (talk) 19:08, 4 April 2010 (UTC)

Prob'ly 'cause nobody pays attention to it anyway... 24.23.197.43 (talk) 05:50, 5 April 2010 (UTC)

Keep THIS area? What area? It's a label on item. 83.31.77.212 (talk) 11:27, 6 April 2010 (UTC)

What is this lizard?

Unidentified lizard

A better view of the head

I caught this lizard in my back yard in Houston, Texas. It could be native or an escaped pet. Can anyone tell me what it is and what we should be feeding it? Tobyc75 (talk) 16:04, 3 April 2010 (UTC)

I vote for the anole lizard, and, in particular, the Carolina anole. Contrary to the name, they are also native to the gulf coastal plain of Texas. The pic here implies that they eat moths, and also warns that they have a painful, but not poisonous, bite: Carolina_anole#Behavior. StuRat (talk) 16:26, 3 April 2010 (UTC)

The first article above contains this text about their diets:

"Anoles thrive on live insects and other invertebrates, with moths and spiders being some of the most commonly consumed prey. Anoles are opportunistic feeders, and may attempt to eat any attractive meal that is small enough. The primary foods for captive anoles are small feeder crickets that can be purchased at most pet stores."

StuRat (talk) 16:42, 3 April 2010 (UTC)

I'll second that. I live in North Carolina, and I usually have several of these guys roaming my yard on any given summer day. They will change their skin color from green to brown, which can be fun to see. But year, that's an Anole. They're endemic to all parts of the American south. It's probably not an escaped pet, its probably just around. --Jayron32 21:07, 3 April 2010 (UTC)

Cheese Bacteria Manufacturers

Does anybody know where I could find information about the companies that produce the lactic acid bacteria used to make cheese?--160.36.38.135 (talk) 16:06, 3 April 2010 (UTC)

What kind of information? If you're just looking for sources of bacterial cultures, a simple Google search for cheesemaking supplies will guide you to a great number of suppliers. Deor (talk) 16:41, 3 April 2010 (UTC)

I'm sorry, I should have been more specific. I am looking to learn about the large scale wholesale distributors.--160.36.38.135 (talk) 16:51, 3 April 2010 (UTC)

I'm still not sure exactly what sort of information about these companies you're looking for. A list of some such firms, linked to their Web sites, can be found here. Deor (talk) 18:30, 3 April 2010 (UTC)

That's a good starting point for me. Thanks.--160.36.38.135 (talk) 18:40, 3 April 2010 (UTC)

fridge

is it ok to lay a fridge on its side? —Preceding unsigned comment added by 66.128.217.54 (talk) 21:21, 3 April 2010 (UTC)

Yes, for transport. But make sure to let the fridge rest in an fully upright position for at least three(?) hours before plugging it in again. At least old fridges have a nasty habit of catching fire if you start it up (plug it in) again too soon after it has been tilted!
--Seren-dipper (talk) 22:23, 3 April 2010 (UTC)

What would make an old fridge start on fire after having been on its side?! Dismas|^(talk) 00:21, 4 April 2010 (UTC)

I would imagine that having the coolant in the wrong place is the problem. StuRat (talk) 01:31, 4 April 2010 (UTC)

No, not quite, it has nothing to do with the freon. The compressor is full of lubricating oil. It is very viscous, and if you put the 'fridge in the wrong position, it will not lubricate some parts of the motor, and it will overheat, just as if you ran a car engine without oil. --hacky (talk) 04:28, 4 April 2010 (UTC)

Anecdotally, an old refrigerator that has been transported on its side and then turned upright and turned on may fail quickly because of metal filings from wear which have not had time to migrate back down to the lowest point. It is folk wisdom I have heard for years, and an old refrigerator I sold to someone failed when they got it home, stood it upright and immediately turned it on. When I have moved an old refrigerator or freezer, I have given it a few hours before turning it on. I have not taken this precaution with new ones. It would be good to check the installation instructions and see if there is any caution regarding new ones. See also [9] regarding the oil issue with laying it on its side. Edison (talk) 19:45, 4 April 2010 (UTC)

Cinnamon causing depression?

I've begun to notice that when I eat things containing (what is shown in the list of ingrediants as) cinnamon, I feel depressed later. Or at least painful memories from the past make themselves known. Is there any known reason for this?

Two things which cause this are Twinings Chai tea (I have never had any other brand of chai tea) and mixed spice. They both contain cinnamon. Yes, I have read the cinnamon article, so I already know that a lot of what is described as cinnamon is actually cassia.

You might claim that this was due to the nutmeg, but as far as I know Twining's Chai tea does not contain any nutmeg. Thanks. 89.243.37.199 (talk) 22:38, 3 April 2010 (UTC)

The sense of smell is known to be very evocative in the stimulation of memories and emotions -- much more so than other senses. However, in aromatherapy cinnamon is listed as stimulating, even being listed as a pain reducer and antidepressant [10]. As it is a frequently used spice in desserts such as apple pie, it is also frequently associated with "hearth and home". If you are concerned that cinnamon is making you depressed or bringing up painful memories from the past, I would recommend contacting a qualified mental health specialist. Random people from the internet are not qualified to assist you in medical diagnoses. -- 174.31.194.126 (talk) 00:46, 4 April 2010 (UTC)

Aromatherapy is nonsense and considered by many including myself to be only for fools, cranks, and charlatans. The effects only occur some hours after ingesting the stuff so the smell has got nothing to do with it. 78.149.241.120 (talk) 10:21, 4 April 2010 (UTC)

Cinnamon is only ingested in very small quantities, so if it is true that it contains a compound which induces depression, it must have a high bioavailability, cross the blood-brain barrier very readily and have a very high affinity for wherever it is acting. This seems unlikely; are you sure it isn't a nocebo effect? How long did it take until you pinned the "source of depression" as cinnamon? --Mark PEA (talk) 10:41, 4 April 2010 (UTC)

I agree - Aromatherapy#Efficacy makes it quite clear that only the most tenuous evidence is available in support of what is quite clearly pseudoscience. The people who provide it are charlatans and the people who use it are engaging in wishful thinking. Oh if only we could cure diseases by sitting around smelling nice things instead of all of that complicated science stuff with expensive doctors and complicated chemicals. Well, sorry, but lovely though that sounds, it's just premium-grade bullshit that's up there with perpetual motion and the flat earth theory. SteveBaker (talk) 16:48, 4 April 2010 (UTC)

Well, at least it is premium-grade bullshit. It could be worse. It could be cheap bullshit. Dauto (talk) 18:25, 4 April 2010 (UTC)

Steve, your first link says "The consensus among most medical professionals is that while some aromas have demonstrated effects on mood and relaxation and may have related benefits for patients, there is currently insufficient evidence to support the claims made for aromatherapy". I take this to mean that it can be shown to affect mood and relaxation, but that any claims beyond that are unproven. Since we are talking about mood, your link seems to support the idea of aromas changing mood, not refute it. StuRat (talk) 15:59, 5 April 2010 (UTC)

Basically yes, but some essential oils may function as drugs (my rationalist, James Randi-admiring chemist friend is sure that roman chamomile sends him quickly to sleep), and also perfumes are a popular and uncontroversial way of using essential oils to affect people psychologically. They don't have very specific or reliable results, but if a perfume can make somebody think you're vaguely nice, I can't see why a different smell shouldn't make a person think he is vaguely unhappy. FWIW, though, I have a bottle of cinnamon essential oil which I put on the burner now and again to cheer me up (I only have three oils, and it's my favourite). It usually helps, although last time I did this the whole thing caught fire, which raised my anxiety level somewhat. 81.131.62.171 (talk) 03:00, 5 April 2010 (UTC)

It's always hard to rule out idiosyncratic effects in individual people. There is some evidence that cinnamonium cassia has anti-anxiety effects in high doses (see PMID 17512974), but I didn't see any mention of mood-lowering effects. Looie496 (talk) 19:00, 4 April 2010 (UTC)

Steve et al, while I agree there are very few rigourous scientific studies available confirming the efficacy of aromatherapy, every time you (or someone else) inhales Olbas Oil when you have a cold, you are confirming its use for yourself! --TammyMoet (talk) 19:22, 4 April 2010 (UTC)

Fixed your wikilink. Though I have to say, I've never used Olbas Oil or anything else for a cold, beyond the usual hydration improving stuff like chicken soup and the like. Somehow I seem to get over my colds just as fast as everyone else. —ShadowRanger ^(talk|stalk) 15:46, 5 April 2010 (UTC)

One other thing to consider is that, since cinnamon is naturally bitter, many people consume it with sugar. This may later lead to a sugar crash, which can affect your mood. StuRat (talk) 16:05, 5 April 2010 (UTC)

.. or it may not: as the article says : "Such a phenomenon has never been scientifically observed". AndrewWTaylor (talk) 17:17, 5 April 2010 (UTC)

Yes, but there is at least a proposed physical mechanism by which this effect may take place, unlike for cinnamon causing depression. StuRat (talk) 17:55, 5 April 2010 (UTC)

Now I think of it, it may lead to disturbed sleep and bad thoughts at night. It cannot be the caffeine since I often drink tea without any problems. 89.240.59.32 (talk) 19:40, 5 April 2010 (UTC)

EJACULATION

How do i prolong ejaculation without using drugs? —Preceding unsigned comment added by KENNEDY NEWTON (talk • contribs) 23:14, 3 April 2010 (UTC)

See Wikipedia:Reference desk/Science#Role of the Pudendal Nerve in male sexual function?, above, where TammyMoet alludes to a technique involving pressing on the perineum. I assume you actually mean "delay ejaculation" rather than "prolong" — I don't think there's any technique that prolongs the act of ejaculation. Comet Tuttle (talk) 00:03, 4 April 2010 (UTC)

That link doesn't seem to be working for me. Vranak (talk)

It was just archived. Try: Wikipedia:Reference_desk/Archives/Science/2010_March_30#Role_of_the_Pudendal_Nerve_in_male_sexual_function.3F. That's the permalink. StuRat (talk) 02:45, 4 April 2010 (UTC)

i read somewhere that frogs have an extended orgasm for almost 3 hours- so maybe thats what the OP wants;))) a prolonged ejaculation, jokes apart comet tuttle is absolutely right - while there are medications to prolong the act and delay ejaculation/ prevent the ejaculation reflex - there are no known medications to prolong the actual process of ejaculationFragrantforever 09:53, 4 April 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)

Has anyone ever tried electrically stimulating this nerve? (Please do not try this without medical supervision)--79.76.239.84 (talk) 10:51, 7 April 2010 (UTC)

Of course they have![11] Lucky rats. Looks promising!--79.76.239.84 (talk) 10:57, 7 April 2010 (UTC)

I am also wondering if anyone has tried violent mechanical stimulation of the prostate to prolong ejaculatory contractions. I bet someone has but Im not going to look for it. Also, would it not be painfull to keep pumping with no throughput?--79.76.239.84 (talk) 11:15, 7 April 2010 (UTC)

April 4

Request for id of Anole(?) seen in Guadeloupe, possibly an Anolis marmoratus (Leopard Anole)

Which species?

One of its green friends, found in the same place, which I am quite certain must be a Leopard Anole.

I just uploaded this photo of an Anole (I think), which was observed in a residential area in Guadeloupe. There are lot of these individuals around the place, also green ones like this Anolis marmoratus or Leopard Anole. The green ones and the grey ones like these seem to interact and they look very similar disregarding the coloration, so I was wondering if the more boring looking individual (who also lost its tail) is just the opposite gender? Possibly the female? --Slaunger (talk) 01:16, 4 April 2010 (UTC)

I'm not sure about the identification, but, are you aware that anoles can change their color, somewhat ? It's not as impressive as a chameleon, but might be enough for those two apparently different anoles to actually be the same gender and species. StuRat (talk) 13:47, 5 April 2010 (UTC)

No, I was not aware of that, but it does explain that I have now also seen yellow-greenish individuals hidden in yellow-greenish leaves, so it may simply be color-changing as you say. On the other hand it is peculiar that sometimes they have a color, which is in sharp contrast to the background, like brilliant green on a white wall. The green ones also sometimes unfold a yellow piece on skin on their throat, which I guess is to defend their territorium. The bright green ones also tend to be somewhat larger than the more boring looking individuals. From what I have seen (and I have seen about 25 individuals now, some may be the same, but with changed color), it seems like approximately half of the population is bright green and the other half of the population is grey/brown/yellow-green (and a little smaller). I feel more and more convinced that it is all the same species, the Anolis marmoratus, and I am inclined to think that there is both a gender and a camoflage aspect to their coloration. At least that would match my observations. --Slaunger (talk) 10:05, 6 April 2010 (UTC)

That sounds reasonable. The one on the white wall couldn't match it, because anoles can't do white. Perhaps it decided to try to look like a leaf, instead, that being the next best type of camo. StuRat (talk) 18:24, 6 April 2010 (UTC)

calories burned per hour of X activity

Where can I find a list of calories burned per hour of all different types of activity? 71.100.3.207 (talk) 02:45, 4 April 2010 (UTC)

Here's one: [12]. Here's another: [13]. StuRat (talk) 02:50, 4 April 2010 (UTC)

Einstein postulate:

Let a pulse of light and spaceship/ train are moving perpendicular to each other such that after sometime the same pulse of light

Strikes and enters spaceship/ train through its one longitudinal side

Travel inside spaceship/ train for some time and then

Leaves the spaceship/ train through its other longitudinal side

Thus are such postulates holds true in abovementioned scenario 68.147.38.24 (talk) 04:29, 4 April 2010 (UTC)khattak#one-420

Yes. The observed lightspeed depends neither on the velovity of the sender, nor on the velocity of the receiver, nor on the direction of the light beam. 213.49.88.115 (talk) 05:39, 4 April 2010 (UTC)

Which is why so many "funny" effects (time dilation, length contraction) happen. Einstein himself joked that his theory shouldn't be called "relativity theory," but "invariance theory," because what is interesting about it is not that things are relative (which is pretty clear even without Einstein), but that some things are invariant (like the measured speed of light), and that is what makes the theory have interesting results. --Mr.98 (talk) 14:10, 5 April 2010 (UTC)

Things become weird for inside and outside observers if the width of spaceship (moving with 0.9c) is increases, e.g 30, 00,000 km. I don’t want to discuss further as this is not a discussion page. Please consider this post as an annotation to my question. —Preceding unsigned comment added by 68.147.38.24 (talk) 20:56, 5 April 2010 (UTC)

Surgical training of doctors with a first professional degree in medicine

The answer to the question may well depend on the country, but what kind of surgical training do doctors have when they get their first professional degree in medicine? In practice, what kind of surgical procedures can a non-specialist doctor with such training handle competently? —Preceding unsigned comment added by 173.49.14.137 (talk) 04:41, 4 April 2010 (UTC)

Don't know for sure. Recently qualified doctors will probably have decent knowledge of certain surgical procedures, but that doesn't mean they're qualified to perform them. As you said, it will depend on the country you qualified in. For example, in the UK, you graduate with your first degree in medicine then you will train further through specialist posts in the NHS. It's at these posts you learn the vast majority of your surgical knowledge, but I think it's pretty much up to you and how much you know and how much trust your supervisors place in you. They may allow you to perform complex procedures if they've observed you doing other simpler ones perfectly, and they're willing to supervise you. There is an exception, though. GP's in the UK can perform minor surgical procedures, but I'm not sure whether these are learnt during GP training, or whether the knowledge is gained through the first degree. Regards, --—Cyclonenim | Chat  17:42, 4 April 2010 (UTC)

If the question "what kind of surgical procedures can a non-specialist doctor ... handle competently" relates to doctors who qualified more than a year ago, then the simplest answer would be "none, unless they've had specific training since qualification". Having said that, it will also depend on the individual, their inclination and their experiences at medical school. When I qualified as a doctor in England ten years ago (and I don't think the situation has changed significantly), newly qualified medical graduates were expected to be able to take blood samples and insert an intravenous cannula without further training, some but not all could suture simple wounds, but anything beyond that depended on further training after qualification -- bearing in mind that most doctors work in a surgical team for a few months during their first year after qualification, and some gain quite significant experience of operative surgery during that time. Surgical skills decline rapidly if not practised regularly. Neurotip (talk) 22:12, 4 April 2010 (UTC)

In the UK: none. [We don't regard venepuncture, IV cannulation or suturing as surgical procedures. In UK medical schools, these minor procedures are taught to and learnt by students prior to graduation.] Axl ¤ [Talk] 18:38, 6 April 2010 (UTC)

In the US also basically none. Medical degrees are granted after four years of medical school. This typically involves two years of classroom education and two years of various medical rotations through different specialties. Each doctor would have rotated through the almost certainly required surgery rotation, but it would be for a short enough time that they would not be qualified for much more than sutures, which they would be more likely to learn in their emergency medicine rotation than in their surgery rotation. In the latter they would essentially just watch since they don't know how to do surgery yet. After medical school doctors in the US are required to go to residency if they wish to become board certified as a practicing specialist or Family Practice or Internist, etc. and residency and later fellowships are where a surgeon would learn surgery. So basically medicine has specialized heavily and that's a good thing. The people that do surgery have a lot of training. In some cases, some students could graduate from medical school having done extra surgery or other rotations such as emergency medicine and been given an unusual amount of training in some sort of basic procedures, but that wouldn't be the norm. - Taxman ^Talk 21:08, 7 April 2010 (UTC)

Moon Tangential velocity

Does any one have a significant number for this velocity, (or is its average along the orbit)?--Email4mobile (talk) 06:00, 4 April 2010 (UTC)

It's about 586 km/h. Dauto (talk) 06:14, 4 April 2010 (UTC)

• It seems to be much less compared to the orbital speed which is about 3679 km/h, Dauto, doesn't it?.--Email4mobile (talk) 10:33, 4 April 2010 (UTC)

I don't know where Dauto got that figure. The tangential velocity (I'm assuming you mean the speed along the tangent to its orbit at its location) will be exactly equal to its orbital plaine. That's how velocities along paths works - the object is always moving in a direction tangential to the path. If you mean the transverse velocity, that is the velocity along a line perpendicular to the line joining the centres of the Earth and Moon, then it will be almost exactly equal to its orbital velocity, but very slightly different because the Moon's orbit is slightly eccentric, that is not a perfect circle (but it is close). --Tango (talk) 13:35, 4 April 2010 (UTC)

I'm sorry. I dropped a factor from my calculation yesterday. The correct value is about 3680 km/h. Dauto (talk) 14:29, 4 April 2010 (UTC)

Thanks Tango and Dauto. I was thinking that tangential velocity is angular velocity which would be one component of the orbital velocity, whereas the radial velocity would be the the 2nd component.--Email4mobile (talk) 16:47, 4 April 2010 (UTC)

Ok, so you did mean transverse, not tangential. Transverse velocity is angular velocity times radial distance. For a circular orbit, all the velocity is transverse. The Moon's orbit is almost circular, so the vast majority of the velocity is transverse. The average radial velocity is going to be zero, since the orbit is periodic so any increase in radial distance at one point in the orbit much be balanced by a decrease elsewhere so you can get back to where you started. More interesting values would be the average radial speed (the absolute value of the radial velocity) and the maximum radial speed. I'm not sure what those are for the Moon, and it would take me a while to work out the formulae, so I'll leave this question for a bit in the hope that someone else can help more easily than I can! --Tango (talk) 16:58, 4 April 2010 (UTC)

I do mistakes frequently, thanks Tango ;).--Email4mobile (talk) 17:15, 4 April 2010 (UTC)

Finasteride

Is Finasteride a topical medicine for male pattern baldness or is an oral medication??? —Preceding unsigned comment added by 119.235.54.67 (talk) 08:48, 4 April 2010 (UTC)

Oral. Ariel. (talk) 09:02, 4 April 2010 (UTC)

The topical medication is Minoxidil. Zain Ebrahim (talk) 20:10, 4 April 2010 (UTC)

Physics definitions

What's the difference between kinetics, dynamics, and mechanics? They all seem to be pretty much the same. 173.179.59.66 (talk) 08:59, 4 April 2010 (UTC)

Disambig: Kinetics (physics), Dynamics (physics). From the kinetics article: "Since the mid-20th century, the term "dynamics" (or "analytical dynamics") has largely superseded "kinetics" in physics text books". Mechanics includes dynamics, plus more. Dynamics is mainly Newton's laws. Mechanics seems to include pretty much everything, click on the image for more details. Ariel. (talk) 09:07, 4 April 2010 (UTC)

Mechanics is traditionally divided into Statics (stationary) and Dynamics (moving). Dbfirs 08:05, 5 April 2010 (UTC)

"Mechanics" is most often used to describe A body of physical knowlege, so we have classical mechanics (often simply called mechanics), quantum mechanics, statistical mechanics... Dynamics is used to describe the part of that body of knowlege that tells us how things change or evolve over time, so the dynamical equation of classical mechanics is Newton's second law, the dynamical equation of quantum mechanics is the Schroedinger's equation, the dynamical equations of electromagnetism are the Maxwell equations. Kinetics usually has a more restricted scope of usage being used to describe things directly rtelated to movement such as kinetic energy and kinematics. Dauto (talk) 13:04, 5 April 2010 (UTC)

Egg heat

Does eating Egg(chicken) generate heat in our body?? It is disastrous in summer I think..... —Preceding unsigned comment added by 119.235.54.67 (talk) 09:20, 4 April 2010 (UTC)

Any food will generate heat in the body when it is metabolized. Eggs are unlikely to be different in that respect.

If you're asking whether chicken eggs contain something that will disturb the body's temperature regulation, then I've never heard about that. Raw eggs may contain bacteria that can infect you and cause a fever, but that's a different story. –Henning Makholm (talk) 10:26, 4 April 2010 (UTC)

Yes, exactly. Thank you! This is the perfect answer - and should have ended this thread right here. SteveBaker (talk) 16:34, 4 April 2010 (UTC)

Eggs are relatively easy to digest, so that would limit the amount of heat produced during digestion. Also, eating chilled eggs will, of course, cause you to heat up less than hot eggs. StuRat (talk) 13:27, 4 April 2010 (UTC)

While that's technically true - it's quite utterly negligable - and besides, the human body has thermo-regulation, if some kind of food did produce a tiny temperature increase for some bizzare reason, the body would simply cut back heat production to compensate for that. So please let's not start off another "old wives tale" that causes a bunch of people to eat their eggs cold in warm weather just because someone felt in need to have something to say!

The correct answer for our OP is:

"No, you are incorrect. Eggs cause neither more nor less heat to be produced in the body than other kinds of food."

Getting into these kinds of detailed technicalities does not serve to provide a clear and useful answer to a very simple question. SteveBaker (talk) 16:31, 4 April 2010 (UTC)

Yes, the human body can thermo-regulate, within a certain range. However, some of the mechanisms for doing so may be objectionable, such as sweating to cool the body and shivering to warm it. Drinking warm or cold fluids is a good way to regulate the body temp when you are feeling just a bit hot or cold, and prefer not to shiver or sweat. (Putting on a sweater is another way to keep warm, of course.) If you do the math, drinking water 60 degrees F below body temp, with a mass 1% of your body mass, should lower body temp by 0.6 degree. That's a huge shift in core body temp, and more than enough to prevent sweating, in many cases. Now, since you're probably not going to eat 1% of your body mass in eggs, the effect is somewhat less, but still significant. The heat generated by digestion may well be more significant, but note that this effect will start gradually, while the actual temperature of the food you eat has a more immediate effect. So, if you are hot now, eat or drink something cold. When the heat from digestion kicks in, hopefully you will be inside in an air conditioned room. If not, then you'll sweat. StuRat (talk) 16:44, 4 April 2010 (UTC)

That may be what happens if you do the math - but I'm not likely to start off with assumption that people (average body mass ~80kg) is going to drink 0.8 liters of water thats just a few degrees above freezing! A typical 'large' chicken egg weighs 50grams. So not 1%, not even 0.1% of body mass and the effect isn't just "somewhat less" - it's an order of magnitude less...and that assumes you're consuming the egg at 60 degrees over body temperature...which is unlikely. This "heat of digestion" is also very small - digestion is an energy-efficient process - it produces vastly less heat than the food itself provides. An egg contains about 300kJ of 'food energy'- but only the smallest fraction of that is produced as heat during digestion. Sweating is one of the body's last defenses against overheating. The first effects are for the mitochondria to reduce conversion of fats and carbohydrates - then blood vessels expand towards the surface of skin to shed heat that way - and only then does sweating kick in - finally, and ONLY after all of those mechanisms fail, will your "body heat" change - which is what the OP asked. The additional heat of digestion from an egg is scarcely likely to do much more than trigger the first of those cooling mechanisms unless the body is already working hard to lose heat. Besides, the issue here is not "Do I eat an egg or do I eat nothing at all?" - it's more like "Do I eat an egg or do I eat something else?" - and if that is the question then the answer is, again, a very clear "NO!" because the heat produced in digesting pretty much any food is going to be very similar. So why are you working so hard to confuse the OP with highly dubious arguments when the answer is so very simple? If you eat an egg - your body temperature won't change to any measurable degree...period. SteveBaker (talk) 17:55, 4 April 2010 (UTC)

1) You can't drink 0.8L of cold water ? I certainly can, as can many people.

2) Why do you assume the person will only eat a single egg ? I can certainly eat several, as can many people.

3) If the heat of digestion is low, then the temperature of the egg is even more significant, by comparison.

4) It certainly seems likely that they are already hot, if they are worried about getting hot from eating eggs. Thus, they may be just about to sweat, or may even be sweating already. So, every little but counts, if they want to keep from sweating more. StuRat (talk) 02:14, 5 April 2010 (UTC)

It certainly seems likely that they are already hot, if they are worried about getting hot from eating eggs - I'm not so sure about that. When I original saw the question removed for medical advice by the same OP, my first thoughts were similar to 206, the OP was referring to the concept of heaty food as described e.g. [14] oh and look I found an article Chinese food therapy. Then I saw the IP looked up to India so I wasn't so sure since I was aware of Chinese concept (it's not uncommon in Malaysia) but not sure that it had an India counterpart (I did search but didn't come across anything useful, the Ayurveda article for example only makes one irrelevant reference of heat).

206 suggests a similar concept in India and in fact looking more closely, I found at least one ref more when I connect it to Ayurveda as 206 suggest [15]. I'm not so sure how the Ayurvedic concept works, heck not even that familiar about the Chinese concept but I wouldn't presume someone being worried about 'heaty' or 'heating' foods is necessarily feeling hot they might just be worried generally because of their belief in the concept. (Balance is of course an important component of the belief, if you eat too many heaty foods like durian you're supposed to eat cooling foods like mangosteen.)

Nil Einne (talk) 03:04, 5 April 2010 (UTC)

I've said this down below and I'll say it again. I'm Chinese, and I can tell you that "heaty", "heating", "cold", and "cooling" DO NOT refer to temperature. They refer to an abstract quantity that has nothing to do with temperature. To use an analogy, the concept of "color" in quantum chromodynamics has nothing to do with the wavelength of the photons reflected from subatomic particles, and the "strangeness" of a particle has nothing to do with how weird it is. --99.237.234.104 (talk) 05:22, 5 April 2010 (UTC)

Well I guess that just further proves the point then (although I'm not convinced the OP is referring to the Chinese concept) Nil Einne (talk) 03:13, 6 April 2010 (UTC)

Off topic conversation about traditional medicine, etc. One possible (but disputed) reference to food allergies

Some people have food allergies with eggs, you might be one of them. Also traditional medicines like chinese medicine and indian ayurveda have for thousands of years described certain foods and other substances as "cooling" or "warming". I don't think modern science recognizes these effects, but then again many things have not been recognized by modern science that may still have merit. 206.53.153.184 (talk) 14:32, 4 April 2010 (UTC)

Another useless answer to a simple question!

• Firstly: Allergies don't cause your body temperature to go up or down - please don't guess when you provide answers here: Allergic_reaction#Signs_and_symptoms has no mention of body temperature change and fever is very clear that this is the body responding to infection. You are thinking of infections causing fever and that's an entirely different matter. Furthermore, you are diagnosing a medical condition and that's not allowed on the Wikipedia reference desks.
• Secondly: There are vastly more ancient claims that turn out to be worthless (or perhaps even dangerous) nonsense than there are scientific claims that are eventually overturned by ancient knowledge. This is undoubtedly a case where the "traditional medicine" answer is 100% incorrect. Look at it this way: If you have to make a decision, by far your best chance to make the best chooice is to go with modern science and ignore all of that ancient/traditional junk.

Please - can't we just answer a simple question with a simple, science-based answer? SteveBaker (talk) 16:31, 4 April 2010 (UTC):

I think your presumption that I hate science blinds you here. Allergic reactions produce histamines, as well as increases in blood pressure heart rate, adrenaline, and cortisol. These are all highly warming, and could raise the sensation of body temperature if not produce an actual fever.

While many traditional cures are bunk, many have also been incorporated into modern medicine, and you well know that natural substances found in plants, fungi, and bacteria are the overwhelming inspiration for biochemical research. Ancient traditions stumbled upon some of these by accident and cultivated a holistic theory of medicine around them. Which ones are valid and invalid remains open to further research. Skepticism does not preclude, and indeed it benefits from a curiosity about historical practices.

Finally, the actual biochemistry of digestion as well as the absorbtion of nutrients through the stomach, intestines, blood, and cells, as well as the interaction of nutrients and organic matter with enzymes in the body is a phenomenally complex process that we don't have a full scientific understanding of yet. So why not consider another source, albeit anecdotal.

Also, hating on wikipedia makes it not fun, so maybe don't do it?68.171.233.151 (talk) 17:50, 4 April 2010 (UTC)

Nobody said anything about hating - and I have no idea about whether you hate science or not. However, giving wildly incorrect guesses to legitimate questions is indefensible...and when you do that, you will be called on that. I'm not about to let people tell untruths to our questioners. The references desks are not about having fun - they are about producing factual answers to serious questions - and if you think otherwise, then you're in the wrong place. So, if you intend to continue to give misleading answers, maybe you are the one that should "maybe don't do it".

Anecdotal answers are also unacceptable here - except, perhaps, to serve to better explain a properly referenced fact. WP:NOR applies here - and so, no - we aren't going to "consider another source, albeit anecdotal" because that would be contrary to the rules, and again, if you think that's acceptable, then you're in the wrong place.

Certainly there are cases where 'traditional cures' happen to work - but there is zero methodical process involved in them. Science has researched many of them - and the ones that turn out to have a basis in fact become a part of the scientific canon. Nobody is denying that substancs in plants, fungi and bacteria are biologically active - it would be exceedingly surprising if they were not! However, random application of biologically active substances holds as many dangers as it does opportunities...which is precisely why we need to take a scientific approach to investigating them.

At any rate, we aren't being asked about some complicated, untested traditional cure. We're being asked a very simple question about an exceedingly well-researched subject of thermoregulation (and homeothermy in particular). This is well understood, established science - and 'traditional' views are simply irrelevant.

SteveBaker (talk) 18:18, 4 April 2010 (UTC)

For clarification, are you 206.53.153.184? Nil Einne (talk) 19:49, 4 April 2010 (UTC)

if you drop the science vs. nonsense dichotomy, you'll see that my response addressed the questioner's personal experience which, by "disastrous" was clearly not a merely technical question about thermal regulation/metabolism but about the op's personal experience of how the digestive process and its aftermath made him or her feel. Allergies are not magic and science has ample explanation for them.

as for traditional medicines, they're interesting historical, cultural, alternative explanations. They don't offer proof but they might be useful for confirmation or as starting points for further research. Surely people might do some useful things that science has not yet tested. Even old practices evolved through processes of experimentation, though not up to modern standards. Further, my post didn't suggest those as "answers", just references, places to look for further research, which is what we do here. Its not original research in any way to link to pages which exist! on wikipedia and address the topics of egg allergies, and traditional categorizations of the effects of food.

in other words, its not original research just because you don't like it, aren't interested in it, or discount it entirely. Its also not anectdotal, as in my personal story, but as in the collected experiences of an entire civilization, which recorded and passed on their observations all the way to present day sources. Readers benefit from a variety of opinions and a discourse about them. I'm not equivocating between science and ayurveda, but there's no reason not to mention a millenia-old cultural belief if it has some direct relevance. Let the reader see what it says and take whatever insight there is to take.

calling answers useless is not civil. Even if you disagree or are right, it stifles participation and offends good faith efforts. decreeing that because many traditional practices haven't stood up to scientific scrutiny (implying that others have) that all are therefore irrelevant is unneccessarily strict for this kind of page. They're relevant because they offer another viewpoint on the subject. The wikipedia reference desk can mention areas within the entire encyclopedia, even if they're outside the scope of a particular sub-page. And just because a field of science has an answer, it doesn't mean that no other information would be relevant. Wikipedia seems more fun when people aren't so critical of responses that attempt to add to the discussion, fun including both usefulness and enjoyment.

Ips 68 and 206 are floating cell phone ips, both mine.206.53.157.72 (talk) 02:35, 5 April 2010 (UTC)

And how is any of this related to the original question? You said "chinese medicine and indian ayurveda have for thousands of years described certain foods and other substances as "cooling" or "warming". That is bullshit, period. If you're Chinese like I am, you'd know that "cooling" and "warming" do not refer to temperature, but are instead abstract concepts that have to do with how "energetic" a food is. You'd also know that the words for "cool" and "warm" as they relate to medicine literally mean "light" and "dark", not "of high temperature" and "of low temperature". Finally, if you actually did some research on traditional Chinese medicine instead of pretending to know what you don't, you would have known that "hot" foods DO NOT feel any hotter or colder than "cold" foods, either before ingestion or after.

Please stop mentioning traditional Chinese medicine. Even if we forget about the fact that it's bullshit, that it cost countless lives due to its fraudulent claims, and that it makes pharmacists rich at the expense of their patients, it's very clear that you do not understand ANYTHING about TGM or its claims. Once again, TGM does NOT say that eating an egg will make you feel hot. It's scientifically obvious that eating an egg will not make you any hotter than eating other foods. --99.237.234.104 (talk) 05:15, 5 April 2010 (UTC)

first, the op doesn't say, "I took my temperature and my core thermal average heat had increased, why?" It was therefore open to subjective interpretation what the perception of heat related to. The literal and obvious choice would be temperature. A secondary consideration would be non thermal physiological effects which mimic heat such as those produced in an allergic reaction. Finally, and for a cultural-historical perspectove, there was the reference to traditional medicine. None of these were obviously correct, all of them could add some insight (scientific or otherwise) for the reader.

claiming tgm is irrelevant because it describes "energetic" as opposed to "temperature" effect assumes the op was describing temperautre. I think the non-fringe idea of a food allergy, however unlikely, permits that there could be some completely "natual" non-thermic cause for a perception of warming. Mentioning tgm and ayurveda was mainly for historical-nutritional background, to suggest that other people had noticed or described effects of food in a way that might be relevant.

my expertise regarding chinese medicine is irrelevant, as I made no specific claims about how tgm or ayurveda categorized eggs specifically, nor represented myself as an authority on those sources. I simply identified a topic which addresses the issue at hand and linked to pages for further research.

the criticism of tgm is understood but also does not disqualify the reference. For one, its a personal opinion. Secondly, even if scientists dispute its concepts, it still carries historical, cultural, and therefore anecdotal support. That was all the reference suggested, so it is within the scope of a reasonable addition.

206.53.147.36 (talk) 10:55, 5 April 2010 (UTC)

Let me say this again. "Hot" and "cold" do NOT refer to heat, temperature, the perception of heat/temperature, or anything remotely resembling heat/temperature. It refers to yingyang, an abstract quantity that has nothing to do with temperature. To use the same analogy I used above, color in quantum chromodynamics has nothing to do with wavelengths of light, and the strangeness of a particle has nothing to do with how weirdly it behaves. --99.237.234.104 (talk) 17:32, 5 April 2010 (UTC)

Firstly, this question is being asked on the science desk - so it's reasonable to assume that a scientific answer is what is required - per heat. Unlike "color" or "strangeness", that word has a fairly unambiguous scientific meaning. Failing that, go to the 'heat' entry in Wiktionary and pick an alternate meaning. As far as I can see, eating an egg will have no measurable effect on the heat in your body for any of those meanings. Please don't start making up your own meanings for words because that way lies madness! SteveBaker (talk) 21:10, 5 April 2010 (UTC)

Collapsing thread that's getting off topic. Buddy431 (talk) 05:39, 5 April 2010 (UTC)

In Chinese traditional medicine egg is a neutral food neither having the heaty spirit or cool nature. Though the answers above cover the science. Graeme Bartlett (talk) 08:49, 5 April 2010 (UTC)

Who said this had anything to do with Chinese traditional medicine? The questioner certainly didn't mention that! That's something being made up by people here who are (for some weird reason) determined to provide a completely useless answer to a really simple question. SteveBaker (talk) 21:13, 5 April 2010 (UTC)

In any case, of the OP is interested in the concept I suspect they're more likely to be interested in the Ayurvedic concept then the Chinese one Nil Einne (talk) 01:47, 6 April 2010 (UTC)

Muskrat

My dogs found, much to their entertainment, a muskrat under a trailer next to my garage. I've read our article and poked around a bit. What I'm wondering is if I need to worry much at all about my chickens being killed by the muskrat. I realize that they're omnivores but is there much need for concern?

For what it's worth, I live on a mountain with some swampy areas along side the road a little ways, roughly 150 - 200', down the road from me. I suspect that's where it has been living. I'm at a loss as to why it would come up the road to my house as the only water near my place is a small spring I have next to my driveway. I'm at the top of the mountain, so everything drains away from my place. Thanks, Dismas|^(talk) 09:54, 4 April 2010 (UTC)

I'm pretty ignorant about muskrats, but if it's just the word "omnivore" that worries you, it shouldn't. Usually that just mean an animal that will eat critters small enough for it to swallow if it gets the chance. Actively hunting and dismembering prey of your own size tends to demand adaptations that the guy pictured at muskrat does not appear to have. Indeed, the article says:

Plant materials make up about 95 percent of their diets, but they also eat small animals such as freshwater mussels, frogs, crayfish, fish, and small turtles.

It's a far reach from that to chickens. Worry about the fox and the hawk instead. –Henning Makholm (talk) 10:43, 4 April 2010 (UTC)

I'd say the adult chickens are pretty safe, but maybe not the eggs or chicks. He probably is living under the trailer because that's a nice ready-made home for him. To get rid of him, you might want to eliminate this home, by putting the trailer on it's side, for example, so there's no space underneath it. StuRat (talk) 13:25, 4 April 2010 (UTC)

Thanks for the reassurances. I doubt he'll stay/come back to live under there. With four dogs, we don't get much wildlife in the yard to begin with, so one taking up residence is fairly unlikely. The biggest problems that we've had with animals killing our chickens have been from an ermine who would take them out in the middle of the night and from a wolf or fox. We were out of town and the dogs were with us when the wolf/fox came that time. Dismas|^(talk) 21:44, 4 April 2010 (UTC)

As for why he went roaming, maybe it's mating season and he's looking for a g/f ? StuRat (talk) 02:04, 5 April 2010 (UTC)

How far does a muskrat ramble during mating season? Edison (talk) 02:40, 5 April 2010 (UTC)

I'm not familiar enough with Muskrat Love to answer that. :-) StuRat (talk) 14:50, 5 April 2010 (UTC)

Is it safe to assume it is a "he"? It could be a female looking for shelter as well. 10draftsdeep (talk) 20:13, 5 April 2010 (UTC)

If it were a female, it would have asked for directions before getting lost and ending up in my yard with four dogs. Dismas|^(talk) 23:30, 5 April 2010 (UTC)

Yea, I just didn't want to say "...(s)he's looking for a (b/g)/f". StuRat (talk) 21:55, 5 April 2010 (UTC)

We have a well-established gender neutral pronoun it for use on animals (I sometimes think it would improve the English language to extend this to humans). I guess "It's mating season and it's looking for a mate" sounds odd though. 81.131.7.235 (talk) 01:43, 6 April 2010 (UTC)

There is also the bizarre "xe" that some editors on Wikipedia like to use. I wish writers in English could adopt the Spanish practice of using the male pronoun to refer to males, the same pronoun as a gender-neutral pronoun for mixed groups, or where gender is not known, and the female pronoun to refer to females. Years ago people parodied gender pronoun worries like changing "congressman" to "congressperson" by arguing that instead of "woman we should say "woperson, but wait: that still sounds male, so let's make it "woperdaughter." Then we could have "huperdaughterity" instead of "humanity." Something written would be a "woperdaughteruscript." Edison (talk) 15:37, 6 April 2010 (UTC)

Speed of light frame of reference

Light cannot go faster than the speed of light. But what about a universe where planets and stars are whizzing around choatically at near the speed of light in all directions. How does the light know which frame of reference to choose? Depending on the choice of the reference frame, the light may appear to be going very slowly, too fast, or even backwards. 78.149.241.120 (talk) 10:26, 4 April 2010 (UTC)

That's the wonder of special relativity and the Lorentz transformation. Light doesn't have to "choose" a preferred frame of reference. The speed of the light is the same relative to every inertial frame of reference, thanks to time dilation, length contraction and the relativistic velocity-addition formula. Gandalf61 (talk) 10:35, 4 April 2010 (UTC)

A minor correction, gandalf. The speed of light is the same relatative to all reference frames, including inertial and non-inertial ones. Dauto (talk) 17:20, 4 April 2010 (UTC)

A minor correction, Dauto, ...including inertial and non-inertial ones when locally measured :-) - DVdm (talk) 17:29, 4 April 2010 (UTC)

We also could say that the speed of the light is the same relative to every inertial frame of reference, hence time dilation etc...

Originally special relativity started with the invariant speed of light and decuced dilation, contraction, addition and transformation from it. We don't really know what causes what. We just know that the speed is invariant - not why it is. DVdm (talk) 10:44, 4 April 2010 (UTC)

And for the original experimental evidence that the speed of light is invariant, see Michelson–Morley experiment. –Henning Makholm (talk) 10:53, 4 April 2010 (UTC)

It runs completely against "common sense" - but light is weird stuff. No matter how you are travelling and no matter how the source of the light was travelling - the speed that you measure is always exactly the same. So even in your chaotic universe, the light never appears to be travelling at anything other than the speed of light - no matter which reference frame you are in. In a sense, light "chooses" all of the frames of reference at once! SteveBaker (talk) 17:18, 4 April 2010 (UTC)

and thus, to make everything come out basically the same in every different frame of reference, einstein et al had to mathematically generate the corrections to length and time between frames of references at different velocities. tada. Gzuckier (talk) 06:20, 8 April 2010 (UTC)

Happiness: A mental illness?

Could Poppy, the unreasonably cheerful character in the film "Happy-Go-Lucky" be described as suffering some kind of personality disorder? And is happiness or a alternatively a serious outlook on life gender specific, for example, does testosterone affect dopamine levels?[Trevor Loughlin]80.1.80.15 (talk) 10:45, 4 April 2010 (UTC)

It's fiction. Its unwise to attempt to deduce facts concerning real life from fiction. 78.149.241.120 (talk) 11:43, 4 April 2010 (UTC)

I've often thought that happiness is inversely proportional with intelligence, which might explain why small kids and the retarded often seem happier. They are thinking "I'm happy because I'm playing with a puppy !" while I'm thinking "I'm depressed because I'm playing with a puppy that will someday die, as will I, and as will the universe". StuRat (talk) 13:16, 4 April 2010 (UTC)

Sorry but that's just dumb. I am usually pretty happy and I am also intelligent. I work with small children and they are a mixed bunch. Some are always happy, some always morose, but most are like me, happy most of the time. Many people who are actually dying state that they are happy - they appreciate every day. Theresa Knott | token threats 14:50, 4 April 2010 (UTC)

If you disagree, please say you disagree, don't call the contributions of others "dumb" (especially since that actually means an inability to talk). I'm not the only person to notice the link between intelligence and happiness: [16]. And, you should know that you can't draw conclusions from a handful of individual cases, you would need a scientific study of thousands of individuals to discount the link. StuRat (talk) 14:46, 5 April 2010 (UTC)

I knew that as well, but I also knew that one of Nature's ways of making sure that my genes would reproduce better, was by making me feel happy about it :-) - DVdm (talk) 13:31, 4 April 2010 (UTC)

There is a correlation between size and intelligence? Since when? (Excluding children whose growth is stunted by malnutrition, disease, etc., which is a tiny minority of small children in the developed world.) --Tango (talk) 13:38, 4 April 2010 (UTC)

The chief criteria for a mental disorder is if it causes problems for the person, or the people around them. If people around her find her annoyingly cheerful though, that sounds more like an attitudinal issue on their end, rather than hers. See this link -- FDA approves depressant drug for the annoyingly cheerful. Warning, may contain humour. Vranak (talk)

The original questioner may want to read about definitions of mental illness. There is much debate in academic and professional mental health fields about this issue. Nimur (talk) 15:02, 4 April 2010 (UTC)

Though I didn't see it, review of the movie made me think the director's answer would be no.

On the other hand, there are some interesting psychological conditions which may be relevant. The most obvious is mania, a condition characterized by near euphoric feelings of optimism and ability. It sounds great but apparently it can also be tied to really hard lows, see bipolar depression, as well as some risky behaviors and a difficulty interacting with mere "mortals".

The movie's main character doesn't seem to have that, though so it might not matter.

Incidentally, if you ask an actual bipolar person, they'll admit that it having uncontrollable bouts of surging energy can itself be scary or even unwanted (perhaps only in retrospect).

More recent research into happiness shows that cognitive behaviors (ie positive thoughts)) can be improved, and brain scans of people who meditate show altered activity levels in parts of the brain linked to happiness.

You could also consider that our moods are partially determined by neurotransmitters like serotonin and dopamine, which could be genetically or periodically higher in some people than others.

As for the bigger picture there's an interesting though marginal theory that depressed people actually see the world more accurately and that happiness involves a kind of cognitive "shield" (see depressive realism).

Finally, its worth considering that poppy is the "normal" one, and everyone else is really bonkers. 68.171.235.107 (talk) 15:23, 4 April 2010 (UTC)

Your second question. Testosterone does not affect dopamine levels. However there is a relationship between Dopamine and serotonin. Kittybrewster ☎ 17:49, 4 April 2010 (UTC)

Also see height and intelligence, happiness and pursuit of happiness (pursuing happiness means you're unhappy). Usually, a relatively simple life leads to more happiness. Children tend to be happier due to generally fewer adverse life experiences and heightened curiosity, and as for why the "retarded" may seem to be happier–some may consider that word to be degrogatory, but it is likely due to the fact that many of them try to live to the fullest. Also, if intelligence is negatively correlated with happiness, does that mean Albert Einstein or Leonardo da Vinci would have been chronically depressed? It is highly unlikely that happiness would be gender-specific...what are the evolutionary advantages of that? ~AH1^(TCU) 22:24, 4 April 2010 (UTC)

No, that is not how correlation works. For example, consider a hypothetical world where anyone with an IQ_{($\sigma =15$)} between 100 and 130 is unhappy (happiness=0) anyone else is happy (happiness=100). In such a world intelligence would be negatively correlated with happiness, but Einstein and Leonardo would still be happy. (This, of course, has nothing to do with the original question – which is more about the meaning of 'disorder' than about happiness). –Henning Makholm (talk) 23:38, 4 April 2010 (UTC)

Happiness is a cigar called Hamlet! :)--79.76.175.65 (talk) 02:16, 5 April 2010 (UTC)

Kidron

Don't know if this is the right place to ask but could anybody tell me what kidron is? I have a collection of books bound in kidron but I can't seem to find what type of material it is... Wikipedia doesn't have an article. I'd be grateful for any help! ; ) --91.49.119.20 (talk) 16:45, 4 April 2010 (UTC)

Are you sure that "kidron" is intended to refer to the material? The Kidron Valley is a location near Jeruselem and Kidron, Ohio is a town in the US - "bound in Kidron" could simply mean "produced in a bookbinding facility located in Kidron, Ohio/the Kidron Valley". If you are certain it refers to the cover material, it may be related to "kid", the term used for young goats, and for their leather. (Kid leather was regarded as a fine and elegant leather, see kid gloves.) -- 174.31.194.126 (talk) 16:57, 4 April 2010 (UTC)

Yes, thanks, I'm sure. A catalogue of the books can be seen here. The Oscar Wilde collection for example states that the edition is bound "in deep red Kidron" and the Macaulay Collection states that in addition to the lambskin and 23 kt gold bound collection the edition is also available in "golden embellished Kidron", indicating (IMO) that Kidron is a lesser material. Thanks for any further help. --91.49.119.20 (talk) 17:16, 4 April 2010 (UTC)

I fixed your external link, which had broken syntax. Nimur (talk) 03:32, 5 April 2010 (UTC)

It appears, in this context, to be a kind of paper-plastic composite imitation leather. Probably a long-discontinued trade name. Google finds a few references implying that the same stuff (or something close enough to be mistaken for it) is also called "skivertex", and skivertex itself has ghits that look like they should be useful. –Henning Makholm (talk) 23:07, 4 April 2010 (UTC)

Thanks soo much!--91.49.83.183 (talk) 10:15, 6 April 2010 (UTC)

April 5

HEADACE

Whats known cure for head ace and flu KENNEDY NEWTON (talk • contribs) 00:05, 5 April 2010 (UTC)

[medical advice removed --Tango (talk) 00:40, 5 April 2010 (UTC)]

We can't give medical advice, I'm afraid. There are lots of head ache and flu treatments available. I suggest you ask a pharmacist, they will almost certainly be able to help. --Tango (talk) 00:40, 5 April 2010 (UTC)

Moved discussion to Wikipedia_talk:Reference_desk#Headaches_and_medical_advice. --Tango (talk) 19:22, 5 April 2010 (UTC)

And the spelling you are looking for is most likely headache --Polysylabic Pseudonym (talk) 10:57, 5 April 2010 (UTC)

If we're removing Cyclonemin's answer, I'll at least reference our articles Headache and Influenza, which has all the information that was contained in his response. Buddy431 (talk) 22:37, 5 April 2010 (UTC)

Or better yet, these: Headache#Treatment, Management of chronic headaches, and Influenza treatment. Buddy431 (talk) 22:42, 5 April 2010 (UTC)

Restoring non-medical advice response, per talk page consensus: StuRat (talk) 19:39, 6 April 2010 (UTC)

Headache's vary significantly in type, but are usually relieved by some sort of analgesic (such as paracetamol) if they're minor. More serious types of headaches exist and depending on the type, various types of drugs can be given such as stronger analgesics or vasodilators. Sometimes headaches are indications of further, more serious diseases and act as a diagnosis aid. Influenza is a virus which is usually unpleasant but killed off by your immune system, and thus does not usually require treatment. However, in immunocompromised individuals (that is to say, those with a weaker immune system such as the elderly, AIDS patients, transplant patients etc) are often at greater risk because their immune systems may not be able to deal with the rapid replication of the virus. In such cases, doctors prescribe antivirals specific to the current influenza virus to try and boost your immune systems removal of the virus. Regards, --—Cyclonenim | Chat  10:59, 5 April 2010 (UTC)

Electrochemistry

"A biological cell is immersed in a 70. mM solution of NaCl at 37°C. The cell's membrane is permeable only to Na+ ions. When the system reaches equilibrium, a potential difference of 55.4 mV is measured between the inside and the outside of the cell, where the inside has the higher (more positive) potential. Calculate [Na+] inside the cell, assuming the amount of Na+ ions transferred is negligible compared to the total amount of Na+ ions in the solution."

I'm aware that, at equilibrium, the chemical potential of Na+ inside the cell equals the chemical potential of Na+ outside the cell, according to m = m° + RT ln a + ZFo. But what are F and o? I plugged in the values but don't get the answer. —Preceding unsigned comment added by 70.68.120.162 (talk) 01:59, 5 April 2010 (UTC)

I think F_o refers in this context to the Faraday constant. I might be wrong, though, because I haven't done any electrochem calculations in a long time. FWiW 24.23.197.43 (talk) 02:20, 5 April 2010 (UTC)

Let me just note that our Nernst potential article covers this. Looie496 (talk) 05:19, 5 April 2010 (UTC)

Cat Behavior - combination of "playing the piano" and mate mounting?

One of my adult female cats has exhibited a new behavior pattern for the past several months that I've never seen before. She has always occasionally "played the piano", the rhythmic massaging of invisible mammaries done by adult cats that were weaned too early. Recently, however, she has combined that with the neck-bite-and-hold that male cats do when they mount the female to mate. So, when I'm laying on the sofa or in bed under a blanket, she will mount my leg and firmly bite the blanket, then begin simultaneously massaging my leg with her forepaws while purring most determinedly. Has anyone else ever seen a cat (especially female) exhibit this behavior? Does anyone have any idea what sort of "needs" are behind this? I can understand both components alone, but together seems a bit odd! 61.189.63.142 (talk) 03:04, 5 April 2010 (UTC)

I'm not aware there's any real understanding of why cats knead. There are plenty of theories, of which yours is one, but we don't really know which one is correct (there may be multiple reasons). This is a key point because unless we know why cats knead, any speculation of why that occurs with some other behaviour is going to be speculation upon speculation. If you think these two behaviours don't go together because the cat is doing X for reason Y, if it's actually reason B this may change things completely. Purr#Reasons for purring is a somewhat related example. If you think your cat is purring because it's contented, what about if it's purring when it's sick, injured or dying? (Personally I like to jokingly say my cat is purring because he broke his bones [17]) BTW if you are concerned about any recent change in your cats behaviour, you should see a vet. Nil Einne (talk) 04:04, 5 April 2010 (UTC)

Note that female cats also grab their kittens by the loose skin on the back of the neck when carrying them. So, she may have kittens on the brain. This "broody" behavior seems especially common right after they are fixed. StuRat (talk) 04:11, 5 April 2010 (UTC)

All the female cats I've had exhibit this behaviour, which I haven't seen in any of the male cats. If she's biting and kneading at the same time, she's probably trying to suckle. I associate it with being relaxed - it usually happens before she goes to sleep. --TammyMoet (talk) 08:45, 5 April 2010 (UTC)

Thanks everyone! 61.189.63.142 (talk) 22:15, 5 April 2010 (UTC)

errr... I hate to suggest it, but it's possible you might be in the line for some kittens. pregnant cats tend to display some odd behavior. have you noticed her carrying small objects from one part of the room to another? --Ludwigs2 22:40, 5 April 2010 (UTC)

My experience suggests the behaviour happens in spayed females more than in entire females, so don't rule out the possibility unless you know she's been done! --TammyMoet (talk) 09:26, 6 April 2010 (UTC)

bioinformatics question

I need to compare amino acid and/or genetic sequences at work and it seems that my bioinformatics and BLAST skills are a little rusty. Can you point me to articles (better if they are fully accessible) regarding similarity, identity and homology of sequences? --121.54.2.188 (talk) 07:44, 5 April 2010 (UTC)

Do you mean BLAST, sequence alignment, BLOSUM ? --Rajah (talk) 10:55, 5 April 2010 (UTC)

Also relevant: Homology (biology), Conserved sequence, and Substitution matrix. -- Scray (talk) 11:30, 5 April 2010 (UTC)

Also keep in mind that Pubmed provides entire open-access books, e.g. Koonin & Galperin, the NCBI Handbook, Coffin, Hughes, & Varmus. -- Scray (talk) 15:18, 5 April 2010 (UTC)

This page from NCBI seems to be a good resource for everything BLAST related. It also has an email address and a link to a mailing list in case you need more specialist advice: [18] 131.111.185.75 (talk) 21:42, 5 April 2010 (UTC)

Sweet :) I think I'll be reading those articles and books this week.--121.54.2.188 (talk) 01:40, 6 April 2010 (UTC)

longest wavelength of EM radiation

In Electromagnetic spectrum, it is stated that the longest wavelength can be the size of the universe. If we use the equation relating frequency and Planck's constant then shouldn't the longest wavelength be 300,000 km ? as the energy of the photon must be integral multiples of Plankck's Constant. Also, the EM spectrum article states that it's continuous, but how can that be if energy is quantized. Maybe this is covered in another article like wave - particle duality, but I don't know. Can someone shed some light on this issue? Thanks! --Rajah (talk) 10:50, 5 April 2010 (UTC)

Energy does not have to a multiple of Planck's constant. You have assumed that lowest frequency is 1 Hz. Graeme Bartlett (talk) 11:51, 5 April 2010 (UTC)

You're confused. The energy spectrum is not quantised. Photons of any energy, no matter how big or small, can exist. Once you pick a photon frequency, then the number of photons for that frequency is quantised ---- that is no fractions of photons are allowed. Dauto (talk) 12:17, 5 April 2010 (UTC)

Energy levels for a certain system, like an electron in an atom, will be quantised, but that doesn't mean that energy in general is quantised. If your photons are being emitted by an excited atom, then there will be a minimum photon energy corresponding to the smallest gap between energy levels of the atom, but there are other ways for photons to be created and, once they have been created, their energies can change (we call that redshift or blueshift). --Tango (talk) 14:30, 5 April 2010 (UTC)

Tango, the energy levels of an atom have an accumulation point as the energy aproaches the continuum (free particles) so the smallest gap between energy levels tend to zero. Dauto (talk) 14:37, 5 April 2010 (UTC)

From a practical point of view, it is very hard to generate electromagnetic waves with wavelengths much larger than an antenna. As such, it is pretty uncommon on Earth to ever observe EM waves as low as, say, 100 Hz; but ultra low frequency and extremely low frequency waves do exist, often related to geological and geomagnetic processes, interactions between Earth and its solar environment, or extraterrestrial/extrasolar sources. Nimur (talk) 15:24, 5 April 2010 (UTC)

Oh, yes, I apologise for my mistake. I should look these things up rather than try an remember my one course in Quantum Mechanics several years ago. --Tango (talk) 15:30, 5 April 2010 (UTC)

There does not seem to be any lower limit for EM waves. They could be orders of magnitude lower in frequency that 1/second. This is despite the effect that an antenna for efficient transmission and reception would have to be beyond humongous. The only limit wold be one of definition. Edison (talk) 18:53, 5 April 2010 (UTC)

You really think that EM waves less than 100 Hz are "pretty uncommon"? Well, just take your portable radio and stand under a high-voltage power line, and see what it does to the reception! The fact is, EM waves with a frequency of exactly 60 Hz are actually pretty darn common on Earth -- any high-voltage power line generates them to a greater or lesser extent. Now it's true that such low-frequency sources only radiate very weakly in relation to the amount of current flowing through them, and that it would take an antenna that's "beyond humongous" in length to transmit such waves -- but if you're talking about a transmission line that's part of the national grid, it would typically be hundreds of miles long (thus forming essentially a super-duper-long wire antenna) and carrying hundreds of millions of amps at maybe 750,000 volts, which would emit a significant amount of 60 Hz radio waves even if only a fraction of a percent of the total energy was radiated. 24.23.197.43 (talk) 04:55, 6 April 2010 (UTC)

Do you understand that your portable radio is picking up harmonics of 60 Hz, and not 60 Hz? Unless your portable radio antenna is about 5000 kilometers long, and connected to a tuned circuit that resonates at such low frequencies, you are not picking up 60Hz waves. Nimur (talk) 20:56, 6 April 2010 (UTC)

OK, I may be wrong about the radio picking up the 60 Hz waves; but that doesn't change the fact that the 60 Hz waves are indeed emitted by the power line, along with the higher harmonics that are the ones responsible for radio interference. It's pretty much the same thing as when a plane crashes in the ocean but there's nobody around to hear it... 24.23.197.43 (talk) 02:23, 7 April 2010 (UTC)

One or two thousand amperes, more like. [19] --Heron (talk) 18:20, 6 April 2010 (UTC)

The U.S. and Soviet/Russian navies used "super low frequency" or "extremely low frequency" transmissions at 76 Hz and 82 Hz respectively to send messages to their submerged submarines. The Sovs put the ground electrodes 60 kilometers apart. The U.S. used electrodes 52 km apart. The input power was a reported 660 kilowatts, while the radiated power was only a few watts, since the antenna was a tiny fraction of a wavelength, but the encrypted transmissions could be received worldwide by deeply submerged submarines. (The submarines couold not reply at that frequency, but could let up a radio bouy to send at more normal frequencies if stealth was not a concern). There were concerns about the effects on humans and animals of the resulting widespread electromagnetic fields. The system could be used to send nuclear attack authorization to ballistic missile submarines, so it had to transmit signals all the time, and could not be kept in standby non-transmitting. To suddenly start transmitting during a time of world tensions would have been a giveaway that something was up. Edison (talk) 15:26, 6 April 2010 (UTC)

Wasn't the bandwidth really low on that comm method? Googlemeister (talk) 16:37, 6 April 2010 (UTC)

Experimental psychology effect - can't remember name

Resolved

I've had no luck with Google and I really need an answer to this question, so I'm going to be obnoxious and cross-post it from the humanities desk to draw some attention.

I'm trying to find the name of a psychological effect I remember reading about a while ago. (It might have been in SuperFreakonomics, a book I no longer have.) The effect was that people tend to prefer to work for free over working for a small amount of money, because working for free feels like charity but working for very little feels like devaluing your accomplishments. Anyone know what the name of this effect is, or a citation for the experiment?

Please don't kill me. I'm really a nice guy, you know. « Aaron Rotenberg « Talk « 17:40, 5 April 2010 (UTC)

I can't say I know that this effect has a name, but Dan Ariely writes about this kind of thing in Predictably Irrational, which unfortunately I don't have on hand.--Rallette (talk) 18:19, 5 April 2010 (UTC)

I think your thinking of:Cognitive dissonance theory (Leon Festinger and Carlsmith 1959) which shows that getting a zero reward can increase liking for the task compared with receiving a small positive reward. see also:[20]--Aspro (talk) 18:38, 5 April 2010 (UTC)

Of course, free t-shirts are a more powerful motivator than either low pay or charity. :-) —ShadowRanger ^(talk|stalk) 19:04, 5 April 2010 (UTC)

Who said free t-shirts? Where? What do I need to do?! Dismas|^(talk) 20:40, 5 April 2010 (UTC)

Dismas you want to volunteer at the Great British Beer Festival and you will get your free staff T-shirt! --TammyMoet (talk) 09:24, 6 April 2010 (UTC)

That's good enough. The "introducing a penalty for parents who are late picking up their children from kindergarten can actually increase tardiness" example is one of the ones I remember reading about. I guess there isn't a standardized name for the specific effect, though. Thanks! « Aaron Rotenberg « Talk « 23:26, 5 April 2010 (UTC)

Cracking a Chest

When doctors refer to cracking a person's chest open, what is the technical name for this surgical procedure? Thanks 92.11.43.155 (talk) 21:28, 5 April 2010 (UTC)

Well, when they're operating on the heart or nearby related organs, it's called open heart surgery. Not sure if there are other operations that use this technique. —ShadowRanger ^(talk|stalk) 21:43, 5 April 2010 (UTC)

May be sternotomy. Dauto (talk) 21:49, 5 April 2010 (UTC)

That's right, it's a specific type of thoracotomy. By the way the definition of open heart surgery on the cardiac surgery page contradicts that on the median sternotomy page. Someone should probably check that out, but I'm afraid I can't as I'm not really meant to be editing wikipedia at all at the moment. (self imposed wikibreak due to exams, and yes I know that I shouldn't be posting this now) 131.111.185.75 (talk) 21:53, 5 April 2010 (UTC)

Thanks. Thoracotomy was just what I was looking for. 92.11.43.155 (talk) 01:01, 6 April 2010 (UTC)

(ecX2) See Cardiac_surgery#Open_heart_surgery. StuRat (talk) 21:51, 5 April 2010 (UTC)

Railroad Engineering

Hi,

I was developing some content for a train-simulation program..

I have a LOT of questions..

I'm asking because I was developing some content for a train-sim and wanted to make the objects 'look' accurate.

i) Does anyone here have a simple formula for converting an axle loading value into a rail weight? (It's something the article on axle loading should maybe have but doesn't)

ii) Typical weights and "rail profiles" for typical 2ft industrial lines would be? ( I've got links to some data for typical US profiles, although I imagine the 'official' standards are tightly controlled.) I am guessing that US logging lines used heavier rails then the Welsh Slate lines though :)

iii) An ISBN or citation for a standard (preferably metric) work on how you lay out trackwork for various gauge construction.. Such works also usally have the formulae for curve limit calculation for various gauges and wheelbases..

iv) A general reading list on the subject of 'industrial' narrow gauge railways ShakespeareFan00 (talk) 23:18, 5 April 2010 (UTC)

Interesting! I actually worked on commercial railroad simulators for Burlington Northern back in the early 1990's - and we didn't need any information in that much detail! Sadly, that means I'm of no help whatever in answering your questions - sorry. SteveBaker (talk) 02:44, 6 April 2010 (UTC)

How is 2 feet an "industrial" gauge? It is less than half standard gauge, and sounds like something you might find at a narrow gauge museum or a little toy ride-on train at an amusement park. Google Book search is your friend for old technical information, because some of it is fully viewable, unlike technical information from recent years. See "Railway engineering" (1899), "Railway engineeering" (1908), "Railway maintenance engineering" (1919), "Steel rails" (1913), "Manual of the American Railway Engineering Society" (1921), Manual of recommended practice for railway engineering and maintenance of way" (1907) and in a limited view "Practical railway engineering" (2005). A cursory search through some of the old and the one new ref did not turn up the terms "axle loading" or "rail weight," though. Where did you find the terms in use? Edison (talk) 14:47, 6 April 2010 (UTC)

Searching Google books for "axle loading" "rail weight" turned up one reference: "Operation and maintenance of diesel-electric locomotives", U.S. Army, (1989)‎ - Page 174 which says "allowable axle loading varies with the weight of the rail, speed of operation, and other factors." "Rails weighing 60 pounds per yard or less will handle about 500 pounds of axle load (2 wheels) per pound of rail weight (that is, about 30,000-pound axle loading for 60 pound rail, 25,000-pound axle loading for 50 pound rail). As rails become heavier, the allowable axle loading increases to an approximate value of 700 pounds per pound of rail for 90 pound rails (that is 63,000 pounds)." No idea if the data extrapolate down to very small and light rails. Incidentally, U.S. practice has been 8 wheels (4 axles) per car, while I have seen old European railstock with 2 axles per car. Edison (talk) 15:03, 6 April 2010 (UTC)

Hmm, Thanks for the first set links, they don't seem to be on 'full' view in the UK though (longer copyright terms perhaps:( ).

2ft Guage certainly WAS an industrial guage, and something similar is still used in some parts of Europe, IIRC parts of New England also had 2ft lines associated with 'forestry'? 212.225.121.81 (talk) 23:34, 6 April 2010 (UTC)

April 6

Terraforming Venus

The first problem for colonizing Venus would be the immense atmospheric pressure. Venus itself is slightly smaller than Earth, so I assume it isn't the increase in the solid mass that is causing the pressure? Is it simply the density of the atmosphere that causes the pressure? According to our article it's about 2.5 times thicker than our own. How might we reduce the size of its atmosphere? Could we somehow siphon it off into space? Perhaps we could transport it to Mars to help build an atmosphere there?

Next is the composition of the atmosphere. How might we dispose of all the harmful gases such as sulpher dioxide and hydrochloric acid? Then there's also the carbon dioxide. There is a huge selection of life from our planet that would be capable of converting this carbon dioxide into oxygen, but the problem is none of it can survive the extreme temperatures of Venus, which are caused by all that CO2. We're in a catch 22, we need to get rid of the CO2 to make the planet habitable, but we can't get rid of it until it is habitable. Not even hyperthermophiles could survive those temperatures. So what could we do? Apparently the temperature in the area from 52.5 to 54 km above the surface has temperatures of 20- 37 degrees Celcius, with pressure only slightly lower than that of Earth. We might grow plants in this area, but how could we suspend them at that altitude?

Then there's the massive amount of volcanic activity ready to undo any changes we make to the atmophere. Is there any way we could control this? I can't think of anything at all.

And finally there's the magnetic field. According to our article on the subject the only reason for the lack of a magnetic field on venus is the lack of convection in the mantle; i.e. the mantle and core are at comparable temperatures. How might we create a temperature difference? Nuclear weapons?--92.251.137.62 (talk) 00:08, 6 April 2010 (UTC)

I think we should wait until after Mars is fully terraformed to even think about doing Venus. They only part I can answer is that we could use blimps to hold plants in the upper atmosphere. They could be black on top to absorb solar heating and could also be filled with lighter gases. StuRat (talk) 00:22, 6 April 2010 (UTC)

I think it might be an idea to merge the moon and mercury into mars to make it bigger so people don't have to adapt to life on earth.--92.251.137.62 (talk) 00:27, 6 April 2010 (UTC)

Do you know how much energy you would need to get the Moon and Mercury into Mars' orbit? And then you have the problem of merging them without just destroying them all. It is completely impractical. --Tango (talk) 00:44, 6 April 2010 (UTC)

I think it's obvious from the title that this is completely hypothetical and certainly won't be possible, never mind practical, for probably thousands of years. C'mon I'm sure you can use your imagination.--92.251.137.62 (talk) 00:50, 6 April 2010 (UTC)

Plus, taking the Moon away from the Earth could cause all kinds of nasty consequences for us here on Earth (like changing the Earth's rotation speed, messing up the magnetic field, major climate change, etc.) Definitely not a good idea, even if it was remotely possible. 24.23.197.43 (talk) 05:04, 6 April 2010 (UTC)

If you have the energy available to move the Moon into Mars' orbit, then you can easily deal with those problems. --Tango (talk) 15:17, 6 April 2010 (UTC)

If people are interested, moving the Moon from Earth's orbit to Mars' orbit, ignoring the Earth and Mars and just considering the Sun and Moon, would take the total energy produced by the Sun, emitted in all direction, for 16 hours. That is a ridiculous amount of energy. --Tango (talk) 15:27, 6 April 2010 (UTC)

Not that it matters, but I got 59 hours. Dragons flight (talk) 18:39, 6 April 2010 (UTC)

Same order of magnitude, so close enough! --Tango (talk) 21:47, 6 April 2010 (UTC)

While you might be able to fix the problems involved with removing the Moon, a much lower tech level could just skip the Moon itself and crash Mars's moons onto the surface and bring some of the larger asteroids from the (relatively) nearby asteroid belt in to add mass. No need to fsck up the Earth and expend huge amounts of energy to enable the Moon to escape Earth's gravity when you've got a whole asteroid belt to cherry pick. Hell, with the asteroid belt, you just have to decelerate an asteroid at the right time and the Sun's gravity will do the work for you. With the Moon, even with near perfect timing to maximize the use of a slingshot maneuver using the Earth's gravity you'd still be fighting the Sun the whole way. —ShadowRanger ^(talk|stalk) 18:46, 6 April 2010 (UTC)

Moving closer to the Sun is no easier than moving further away. In one you have to accelerate the object and in the other you decelerate it, but that's the same thing as far as energy is concerned. Also, the total mass of the asteroid belt is only 4% that of the Moon (and Mars' moons don't add much to that). --Tango (talk) 21:47, 6 April 2010 (UTC)

See Terraforming of Venus. There are various ideas there on how to do it, but none of them particularly feasible, even assuming reasonable future technology. --Tango (talk) 00:44, 6 April 2010 (UTC)

seeing red

I happened to be on a path with a translucent green roof. After getting out of the path it seems that all that I look at have a tinge of red. The same thing happened when I was looking on an translucent orange window of a jeepney but it seems that other things I look at this time have a bluish tinge.--121.54.2.188 (talk) 01:49, 6 April 2010 (UTC)

See afterimage, or more generally, sensory adaptation. TenOfAllTrades(talk) 02:06, 6 April 2010 (UTC)

Your eyes have red, green and blue sensors - when you see a lot of one color, the brain dials down the output of sensor(s) that pick up that color. When you step out into normal light, it takes a while for the brain to adjust - and hence, everything takes on a tinge which is complementary color of the one you'd been looking at before. So in green light, your green sensors are dialled down. When you step into white light, green is suppressed and everything is seen in red/blue only. The color that is a mixture of red and blue is "magenta" - which is a reddish purple. Orange (which is really dark yellow) is a mixture of red and green - so in yellow/orange light, the red and green sensors are suppressed - and when you enter white light, the blue sensors are the most active. Hence, the colors you saw pretty much exactly fit the theory. The effect fades over maybe 10 seconds as your eyes return to normal.

You can do an experiment to prove this. Click a couple of times on the image at right until it's only thing in your browser window - make the window full-screen. Now, stare fixedly at the nose for a full 30 seconds - then immediately look at the blank part of the screen. You should see a 'normal' colored picture of our glorious leader. This works because the picture at right is a colored "negative" of the desired image. When our eyes start to shut down the blue sensors - we'll see flesh-tones. (You may need to quickly blink to see it a little better.)

SteveBaker (talk) 02:32, 6 April 2010 (UTC)

I read once that one reason for Scrubs (clothing) being green was to reduce the distraction of green afterimages from extended staring at brightly lit surgical procedures. Our article on scrubs does not mention that particular reason, might try to see if I can find a source later. Vespine (talk) 04:39, 6 April 2010 (UTC)

Oh! To contrast with all of that red blood splattered everywhere?! Well, it's possible I suppose. So I suppose the reason all of the security guys on the Starship Enterprise wear red is to avoid this exact effect when massacring Romulans? SteveBaker (talk) 13:17, 6 April 2010 (UTC)

I think they are designed to contrast with blood, but so that you can tell if there's blood on your scrubs and change them before infecting other patients. Blood also shows up nicely against a traditional white nurse's uniform. However, now they prefer patterned prints, which seem more designed to hide contamination than to make it obvious. StuRat (talk) 13:55, 6 April 2010 (UTC)

What causes color?

Color is clearly determined by what wavelengths of light are transmitted off an object, but why do things absorb certain wavelengths and reflect others? Why, for example, are crystals of copper sulfate pentahydrate brilliant blue (while its anhydrous form is white), rather than any other color (or colorless)? Color clearly depends to some extent on structure, as evidenced by the various allotropes of phosphorous or the copper sulfate example above, but then again, just loose nitrogen dioxide molecules floating around make a brown gas. On a related note, what would cause something like glass to be transparent and colorless? Thegreenj 02:20, 6 April 2010 (UTC)

The article on Transparency and translucency probably answers all of your questions. It is a pretty good introduction to the physical properties of color and light from what I can see.

Note of course, unstated above, is that it is the brain that translates wavelengths into what we call "colors" (which is a perceptual property, not a physical one). So to be perfectly consistent, you'd want to not say "brilliant blue" but "reflects EM waves in the (insert measurement) range." It's the brain that makes it "blue", based on its interpretation of signals from your eye hardware. (The brain could be wired differently—some animals can't distinguish between wavelengths that humans can, and can see some wavelengths that humans can't.) --Mr.98 (talk) 02:39, 6 April 2010 (UTC)

As for colors, each atom has a bunch of electrons at a small number of specific energy states (called quanta), Light hitting them causes them to change energy states, and when they return to the original state, they radiate photons at specific frequencies, or colors. This is part of quantum mechanics. StuRat (talk) 13:30, 6 April 2010 (UTC)

A minor (but important) quibble — quanta (singular quantum) are discrete packets of energy (generally associated with transitions between energy levels), not the energy levels themselves. That is, photons are quanta of electromagnetic energy. In a system that can be modelled as having discrete energy levels (as in the example of electrons bound to an atomic nucleus), one can describe the associated energy levels as quantized; the arrangement of electrons (which will determine the system's energy) can be described as its quantum state. TenOfAllTrades(talk) 14:09, 6 April 2010 (UTC)

Thanks for the responses! One more follow-up question: are there models that can be used for theoretical predictions EM absorption/emission based on a molecular structure? Thegreenj 02:57, 7 April 2010 (UTC)

What's the nasty stuff in coal ash?

Could someone who can read this paper please list the "minerals and leachable metals" it names as primary sources of toxicity? 99.25.114.26 (talk) 07:53, 6 April 2010 (UTC)

What is leachable is going to depend on what is in the coal and slag to start with. See Fly_ash#Groundwater_contamination, etc.--Aspro (talk) 08:15, 6 April 2010 (UTC)

Oh, great, you just happened to catch me reading up on coal-to-liquids technologies! Well, since these topics are closely related, I'll tell you what my source (Higman and van der Burgt) says about leachable toxic metals in coal ash. Here's a comprehensive list of the toxic metals and their concentrations:

Arsenic, 2.1 ppm (volatile)

Boron, 35 ppm (relatively nontoxic)

Barium, 130 ppm (but not all of it is in leachable form)

Beryllium, 1.2 ppm

Cadmium, 0.07 ppm (volatile)

Cobalt, 3.5 ppm (somewhat radioactive; volatile if reduced)

Chromium, 7.0 ppm (only slightly leachable if reduced)

Copper, 9.2 ppm

Mercury, 0.13 ppm (volatile)

Manganese, 84 ppm (not very toxic)

Nickel, 10 ppm (volatile if reduced)

Lead, 14 ppm

Antimony, 0.57 ppm (may be volatile if reduced)

Selenium, 3.1 ppm (volatile)

Strontium, 316 ppm (radioactive)

Thorium, 8.4 ppm (slightly radioactive, nonleachable)

Uranium, 2.1 ppm (radioactive, practically nonleachable)

Vanadium, 17 ppm (partially leachable)

I should also mention that most coal-to-liquids processes are much better environmentally than conventional coal-fired power stations, because they produce little if any fly ash, and because the bottom ash comes out in the form of an inert non-leachable slag that traps all the toxic metals instead of spreading them far and wide. As for the volatile metals, instead of simply being dumped into the atmosphere as in a conventional power plant, they enter one or more of the gaseous byproduct streams, from where they can be scrubbed relatively easily. Coal-to-liquids also allows the sulfur to be removed and recovered almost completely, because it's removed from the coal as H₂S, which is readily scrubbed from the off-gas stream by a wide variety of methods, and can be converted to elemental sulfur, whereas in a conventional plant, it goes into the flue gases as SO₂, which can only be recovered as calcium sulfate, a relatively low-value material. 24.23.197.43 (talk) 09:00, 6 April 2010 (UTC)

See also Polycyclic aromatic hydrocarbon, soot, and fly ash. 92.29.111.79 (talk) 22:42, 6 April 2010 (UTC)

Soot and PAHs are not metals and therefore are technically outside the scope of this discussion; however, they are indeed found in fly ash and are potentially harmful to human health. (Note also that coal-to-liquids technology allows these to be recycled to extinction, which is rarely if ever possible with conventional coal-burning technology.) 24.23.197.43 (talk) 01:17, 7 April 2010 (UTC)

2012-- mayan civilization

is the hoax about the end of earth in any scientific way correct? if its so what scientists are doing to save the earth?--Myownid420 (talk) 12:45, 6 April 2010 (UTC)

• See Mesoamerican_Long_Count_calendar#2012_and_the_Long_Count, which states "...stated that "We have no record or knowledge that [the Maya] would think the world would come to an end" in 2012. As well as 2012 phenomenon. Dismas|^(talk) 12:50, 6 April 2010 (UTC)
• No, and consequently, not anything they don't do anyways. See http://www.2012hoax.org/ for detailed rebuttals of all the various doomsday fantasies. --Stephan Schulz (talk) 12:52, 6 April 2010 (UTC)

The Mayan clock has a whole bunch of cycles built into it. These are like the hands going around on a modern-day clock - or the cycles we have of months, years, decades, centuries and millenia. For the Mayans, 2012 would be like the end of a millenium for us. Of course, quite a few nut-jobs thought the world would end on Jan 1st 2000, but the Mayan calendar is even more attractive to those kinds of people because it's that little bit more obscure. The Mayans didn't predict that the world would end - and even if they did, what the heck did they know that we don't? The world (and the universe in general) are ruled by 'chaotic' (in the mathematical sense) systems. Making any precise predictions (to within an accuracy of a single day) for more than a few tens of years into the future is essentially impossible - not just because we can't measure things that accurately - but also because the fundamental mathematics of chaos theory doesn't permit that kind of precision.

So the Earth doesn't need saving (well, not from the first cycle of the Mayan calendar ending). Hence, scientists aren't doing anything special because of it. Now, can we all please go back to worrying about our lack of defense against killer asteroids, or the all-too-real certainty of disasters from global climate change and the certainty that we're about to run out of materials like copper that are essential to our present way of life? If the general public spent half as long worrying about those things as they do about ridiculous nonsense like Mayan calendars, the world would be a much more secure place! SteveBaker (talk) 13:09, 6 April 2010 (UTC)

You might be interested in a similar discussion over at Wikiversity, which focuses on the "galactic alignment" around that date: [21]. StuRat (talk) 13:10, 6 April 2010 (UTC)

That's nuts! Nothing else in our galaxy is remotely close enough to affect us - and any alignment would be tough to define given all of the speed-of-light issues involved. Also, things move so incredibly slowly that if some grand alignment were happening in just a couple of years, we'd already be feeling whatever effect there is supposed to be. "Galactic alignment" is a deeply stupid idea! SteveBaker (talk) 03:24, 7 April 2010 (UTC)

Even assuming that global climate change is happening like they say and will lead to big disasters for the civilized nations somewhere down the road (and there is real dispute about both these claims), it's not nearly as immediate as the threat that global jihad poses to our freedom and our way of life. If the public spent more time worrying about that danger and less time about stuff that won't happen until many years from now, we would all be much safer. 24.23.197.43 (talk) 01:26, 7 April 2010 (UTC)

I really don't agree about that. Sure, the terrorists can make a lot of trouble - but I don't see them being able to produce world-wide "end-of-world" types of effects. Even the worst-case scenario of them getting hold of a nuclear weapon would likely only take down one city - it would be tremendously upsetting and even somewhat disruptive - but life would go on in pretty much the same way elsewhere. I would expect to see chaos on the scale of Hurricane Katherina...possibly more if it were NewYork, Washington or someplace like that - but it's not an end-of-world scenario. Incidentally - if you still don't believe that Global climate change is real - you should maybe actually read that article you linked to. SteveBaker (talk) 03:24, 7 April 2010 (UTC)

Early Earth

Suppose I had a time machine and went back 100 million years on some continent. If I brought a sturdy tent, camping tools, minimal food and water to last a month and a couple of rifles and shotguns, do you think I would survive a month? --Reticuli88 (talk) 14:37, 6 April 2010 (UTC)

• That would put you in the age of dinosaurs. Back then, the air was breathable, although somewhat higher in oxygen, I think. The water in rivers and lakes should also be drinkable. Food might be a bit of an issue, as none of the food we've bred for our consumption yet existed, and I think that was even before flowering plants, which provide much of our current diet. I suppose you could shoot small dinos for food, until you ran out of ammo. You'd also need some type of shelter than would keep you safe while you slept. A tent wouldn't do it. If you could find an empty cave, then you'd only have to defend one side, and perhaps you could rig alarm bells to ring if anything entered. Shotguns and rifles might not kill an attacking dino quickly enough, so something more like a bazooka might be in order. Or, a flamethrower might work. It wouldn't kill quickly, but might be weird enough that it would make a dino back off. Also, to protect against ambush predators, you might want a mask with eyes on the back of your head. This is a technique they use in India to protect against tiger attacks. One other thing to worry about would be disease. You would probably carry back many diseases that the dinos would have no defense against, so they would die off like flies. They might also have some disease which no longer exists and which you have no defense against. So, you'd probably want to wear a full anti-contamination isolation suit. StuRat (talk) 14:48, 6 April 2010 (UTC)

• Just FYI, flowering plants have fossil evidence going back 140 million years. So they would exist, and if you brought back your own flowering plants (time travel paradoxes be damned) there would be pollinators available to keep them alive and reproducing (assuming the pollinators recognized them as potential targets for feeding; pollinators and flowers evolved hand in hand, so 100 million year old pollinators might not recognize your plants). As you noted, agricultural crops generally would not exist in a usable form, so you'd have to fall back on the hunter/gatherer diet of fruit, nuts and berries supplemented with meat from hunting. —ShadowRanger ^(talk|stalk) 15:40, 6 April 2010 (UTC)

• If you are stupid enough to carry several guns (how many to you plan shooting at any one time?) but no ammunition, probably not. Apart from that, possibly. 100 million years ago the atmosphere had about 30% oxygen - safe to breathe, but fire will be a much higher risk. CO₂ was probably 3-10 times more prevalent than today, but still a factor of 10 below where you would expect direct physiological effects. Avoid T-Rex and don't catch a fungal infection, I'd suggest. --Stephan Schulz (talk) 14:57, 6 April 2010 (UTC)

Interesting Stephan...what would happen bullet-wise if you shot a gun in 30% oxygen/different oxygen setups? Would it catch fire/have adverse affects? any idea? In terms of 'food' if you killed a pig size animal you could theoretically live on its meat for quite a number of months, assuming you can cook and store it in a way that it won't go off and make you ill. 194.221.133.226 (talk) 15:33, 6 April 2010 (UTC)

Perhaps the lubricating oil on the gun might catch fire. As for storing food so it won't spoil, how would they do that ? StuRat (talk) 15:50, 6 April 2010 (UTC)

Salt. However, I think we're missing the point here. OP seems to be bringing "food and water to last a month" with him.Rimush (talk) 15:53, 6 April 2010 (UTC)

"her" --Reticuli88 (talk) 15:59, 6 April 2010 (UTC)

(ec)Or using a smoker. Beyond that, the original poster was only interested in living there for a month and returning, not living off the land. She could arrive with a few cases of granola bars, beef jerky and vitamin pills and bypass the need for food acquisition. I think she mostly wanted to know whether a well-equipped, well-prepared human could survive the hazards of the time without excessive measures like breather masks or environmental suits. —ShadowRanger ^(talk|stalk) 15:56, 6 April 2010 (UTC)

They said "minimal food and water", so I took that to mean just enough for emergencies. Also, would they bring bags of salt with them, or mine them once there ? StuRat (talk) 15:57, 6 April 2010 (UTC)

Actually, they said "minimal food and water to last a month". I take that to mean "the minimum amount of food and water to last a month", since any other interpretation is too subjective to be useful. —ShadowRanger ^(talk|stalk) 15:58, 6 April 2010 (UTC)

Great answers, thanks! I did mean to bring enough food to survive but if I wanted to snack more, I imagined I would be eating some exotic fruit or hunting small dino game. I guess the fruit would not be possible. Wouldn't there be other predators to be afraid of besides T-Rexes? Would there be any side effects of breathing 30% more oxygen? Would the sky look different to me? Would the moon look larger? Would I smell the difference in the atmosphere? --Reticuli88 (talk) 16:07, 6 April 2010 (UTC)

A similar question was discussed before here [22]. I think you'd absolutely want to bring some good vitamin suppliments along. Who knows what important nutrients are missing in dinosaur meat.APL (talk) 16:30, 6 April 2010 (UTC)

As I noted earlier, fruit might exist (flowering plants and fruit frequently occur hand in hand). Of course, you'd have to figure out if it was poisonous or not. There would be numerous predators to deal with, though technically, no T-Rexes (they existed only for a few million years immediately preceding the extinction, not 100 million years ago). You'd probably be a bit light headed for a little while on arrival, but the increased oxygen is within human adaptive tolerances (oxygen toxicity of any sort doesn't seem to kick in until the atmosphere is 50% oxygen, and I believe it tops out around 30% historically). You wouldn't "smell" the difference in the atmospheric composition as far as the excess oxygen goes, though obviously smells produced by now extinct flora and fauna would likely be different. The increase oxygenation would speed decomposition too, so rotting material would smell more intensely, but stick around for shorter periods. Can't say what the sky or Moon would look like; technically, I believe the Moon was a little closer, but I doubt it would be particularly noticeable. —ShadowRanger ^(talk|stalk) 16:23, 6 April 2010 (UTC)

Just a note; many modern "dangerous" animals are more scared of humans (and consequently more dangerous) due to evolutionary pressures (to wit; we killed and ate the ones that weren't afraid of us). While there were more predators in the period described, you'd probably be safe around the herbivores; they wouldn't know enough to consider you a threat. The predators might be a problem, but they wouldn't have any particular experience or instinct for dealing with humans; simple traps and your weapons would likely encourage them to seek easier prey. —ShadowRanger ^(talk|stalk) 16:28, 6 April 2010 (UTC)

I would think you might tend to hyperventilate, when you exerted yourself, in an atmosphere with more oxygen and carbon dioxide. There were lots of other predators, like velociraptors, although those didn't actually appear until 75 million years ago. Actually, even if it was around, a T-Rex might ignore you, if something bigger was on the menu. BTW, the giant insects might be an annoyance. The days would also be noticeably shorter. StuRat (talk) 16:33, 6 April 2010 (UTC)

Velociraptors, were the size of a modern day chicken - really not that much to worry about! (That goddamn Jurassic Park movie has a lot to answer for!) It seems possible that T-Rex was only a scavenger - although this is a controversial view - maybe not too much to be concerned about? SteveBaker (talk) 03:11, 7 April 2010 (UTC)

Don't forget to bring a supply of antibiotic pills, and you might as well start taking them immediately; there are presumably trillions of nasty germs that'll land on you from which you have no immunity, because they've died out by 2010. I don't have it at hand, but GURPS Time Travel is an RPG sourcebook that has lots of good information like this for the practical time traveler. One sidebar helpfully tells the reader: Stop reading the rest of this book for a minute, and memorize this formula, just in case you are sent way back in time at some point in your life: 75% saltpeter, 15% charcoal, and 10% sulfur. Comet Tuttle (talk) 18:17, 6 April 2010 (UTC)

So, where do you find saltpeter? Memorizing the formula is only useful if you're in a well-labeled chemical supply closet. You need to be able to locate and identify natural sources, understand how to process them, and have enough general understanding to improvise substitutes if necessary. Nothing short of a solid understanding of chemistry and physics is sufficient to really re-manufacture modern conveniences - there's not simply "one formula to memorize". Nimur (talk) 21:15, 6 April 2010 (UTC)

Nimur, I can see you are not exhibiting that "can-do" attitude that will allow you to adequately exploit your futuristic knowledge when you get catapulted back a thousand years. See Lord Kalvan of Otherwhen — and, in fact, the main character is a (part-time, I think) reference librarian, just like you and me. Here's one link about naturally occurring saltpeter and speculation on how it was processed, and the quality of early black powder. Comet Tuttle (talk) 23:01, 6 April 2010 (UTC)

Another good book to read, of course, is The Mysterious Island by Jules Verne. In it you can learn such useful skills as smelting iron from ore and making nitroglycerin from seal blubber, even if you're stranded on a strange island with nothing but the remains of a hot-air balloon and the glass face of a watch. Of course, you may have to adapt the nitroglycerin recipe; I don't think you're too likely to find seals 100 million years ago. —Bkell (talk) 02:54, 7 April 2010 (UTC)

A good precaution, but I'm not sure how problematic it would be in practice. The mammals of the time are so different from modern day humans that it would be a fairly uncommon disease that would pose a risk to you, and saurian diseases that can affect mammals are even less common. Granted, if you stay there too long, the germs you carry with you might have time to exchange genes with the local germs and "teach" the local germs how to interact with your biology, but I would think the biggest threats would be from pathogens that don't rely on adaptations to individual species' biology. For example, virtually no virus, and only extremely rare bacteria and monocellular parasites would pose a threat. Fungi and multicellular parasites would be much more likely to cause problems. —ShadowRanger ^(talk|stalk) 18:26, 6 April 2010 (UTC)

Just as an aside, it is possible to survive almost anywhere for a month, if you import enough provisions. Antarctica, the middle of the ocean, outer space... the real question is whether one would be able to survive for an indeterminate period of time (a condition which would force one to integrate oneself into the environment). that's a much more difficult task to accomplish. --Ludwigs2 18:52, 6 April 2010 (UTC)

Stu you wouldn't need a shoulder launcher missile weapon to deal with dinosaurs that could fit inside a cave. I think an M14 rifle would be of sufficient calibre to deal with them. For handling the larger dinosaurs you can use an RPO. A flamethrower would require insanely close range and run through ammunition ridiculously fast. An M107CQ carbine firing .50 BMG would be anotehr excellent weapon to bring with you if you could. So those three weapons in that order of preference would be my choice. Rather than sleeping in a cave, as caves are hard to find are chock full of poisonous spiders and snakes, I think a lined hole in the ground with overhead cover would be preferable.--92.251.159.250 (talk) 23:03, 6 April 2010 (UTC)

The flamethrower would also be useful for swarms of small predators. Most predators would back off with one blast from it, you wouldn't need to actually hit them. They would think: "that thing is dangerous, I'm outta here". StuRat (talk) 01:34, 7 April 2010 (UTC)

An Abrams tank might be useful. It could tow the trailer with fuel and supplies. I expect T-Rex tastes a bit like chicken. Edison (talk) 23:21, 6 April 2010 (UTC)

Meh if you want to use something like that use an M1128 MGS. It's basically an APC with a tank gun on top, and 3 machine guns of various calibres attached to different spots. You could sleep inside and also carry provisions in the vehicle itself so you wouldn't have to risk yourself outside. I don't think we're allowed to bring vehicles however.--92.251.159.250 (talk) 23:36, 6 April 2010 (UTC)

As to the Moon, see Orbit of the Moon#Tidal evolution and Tidal acceleration. The Moon is currently receding by 38 mm/year, but the average rate over the last 620,000,000 years was only about 22 mm/year. So in the last 100,000,000 years it must have receded by somewhere between 2,200 and 3,800 km. It would look maybe 1% larger: as stated above, not enough to notice. The day would also be about 20 minutes shorter than now.

On the other hand, the proper motion of many of the stars over 100,000,000 years would be plenty noticeable. If you know what the constellations look like today, and had an opportunity to see the night sky without being eaten first, you would find the differences obvious; I suspect you would not find any recognizable constellations at all. And even if you did, you would also find the axis of the Earth pointing in a different direction due to axial precession (well, probably different; it might have rotated by an integer number of times and returned to the same place, just by chance). So if there was a pole star like Polaris today, it would be a different star for that reason. --Anonymous, 23:34 UTC, April 6, 2010.

If you were on the Earth either 100 million years ago or 100 thousand years ago, if you were in an area teaming with a lot of life, I think your senses would be bombarded with stimulation more so than most people generally experience today. Smells, sights and sounds would be a presence that we would only experience today if we planted ourselves amidst some large and largely undisturbed-by-mankind plot on the planet. Human activity, I think, has suppressed the imposition that all other forms of life would have on us. Bus stop (talk) 03:03, 7 April 2010 (UTC)

I think the biggest problem is likely to be food (unless you bring enough with you). We have no clue whether dinosaur meat would be edible - after all, there are plenty of reptiles with poisonous flesh. I'd want to try to find a crocodilian of some kind to hunt - although 100 million years ago is a bit far back and you'd be looking for proto-crocodilians (Crurotarsi). But those creatures appear to have changed relatively little over the intervening time - and since we know that Alligator meat is very edible (rather delicious, actually), that would be your best bet. You might also want to hunt and eat mammals of that period - again, on the grounds that there are few (if any?) present day mammals with poisonous flesh. Fruit and veg would be available - but again, how do you know what you can and can't eat? Roots and nuts have similar problems. You could certainly start taking chances on strange foods if you got desperate - but it's a hard risk to assess. Hiding out from large carnivores might not be so hard - the ratio of carnivores to herbivores tends to be fairly constant over time - and you can certainly live for a long time in the wilds of modern day Earth without having problems with them. I also suspect that you'd have little problem with bacterial/viral diseases. Most diseases don't cross species very well - and nothing back then is evolved to infect humans. Fungal problems might be a bigger issue - but if you can keep your feet dry and body clean - and take care to dress open wounds properly - you ought to be able to fend off that kind of attack for a month. Water is just water - I don't see any special problems there either. Overall, I think that anyone who could survive a month somewhere out in the wilds of modern earth would have little additional problems 100 million years ago. Just don't lose the spare batteries for your time machine...that might be bad! SteveBaker (talk) 03:07, 7 April 2010 (UTC)

If you were forced to try the local foods, I'd recommend some sort of methodical poison tests like described in this article [23]. (And its references.). It's far from a sure thing, but it would at least lessen the risks. APL (talk) 04:39, 7 April 2010 (UTC)

Poles on a DC Motor

There seems to be many different types of DC Motors. Each has a different way/pattern to how the external poles are arranged. As the DC Motor ages the markings tend to disappear as does the manufacturers data plate. This condition leaves a DC motor without markings or data plate from which to identify the DC Motor. I have a very old possibly 1971 DC Motor in a old golf cart now used for pleasure as a Low-Speed_Vehicle(LSV)licensed for the streets. The wiring is in question and I want to know how I can know with certainty which DC Motor pole is used for what? How can I check the motor to make certain it is good? Thank You Norman pickett (talk) 15:22, 6 April 2010 (UTC)

Well, the obvious answer is to hook the positive and negative leads up one way, see if it works, and, if not, try the other way. Some motors will go backwards when hooked up at the reverse polarity. Others will do nothing. Are you afraid that hooking it up backwards could damage it ? StuRat (talk) 15:54, 6 April 2010 (UTC)

The plate on the motor may be illegible, but have you tried Googling on all the information you have on the cart (like make, model, chassis number etc.) There are a lot of cart fanatics out there with wiring diagrams. There are also a lot of amps that can melt things if you get it wrong. A meter should be able to identify which field winding is which. The poles to the commutator would (I imagine) cause the meter to flicker unsteadily as you turned the rotor by hand. The good thing is that at a 1970s machine is unlikely to have any fancy electronic control circuits. On the bad side: it is sacrilege to use a golf cart for anything but the proper purpose and you may find a thunderbolt strikes you down the first time you take it out for a spin.--Aspro (talk) 16:50, 6 April 2010 (UTC)

Flaming globes of Sigmund - dreaming phenomenon

Often, a person awakening from a dream retains the memory of a striking sentence or phrase which impressed the dreamer as funny, profound, or otherwise significant. However, on later inspection, the phrase proves meaningless or absurd. The phenomenon is illustrated in the Seinfeld episode "The Heart Attack", in which Jerry awakens chuckling, scribbles "flaming globes of Sigmund" on a scrap of paper, and goes back to sleep convinced that he has composed a joke. In Jerry's case, he cannot remember the actual meaning of his scribblings the next day, though he retains a vague sense that they were important. In my case, I often awaken with a memory of specific words, which seem, in the immediate aftermath of awakening, to retain their meaning, only to lose it gradually as the morning wears on. The words remain, but the sense of meaning dissolves. Is there a scientific term for this kind of phenomenon? How prevalent is it? Has it been the subject of any notable research? LANTZY^TALK 16:40, 6 April 2010 (UTC)

I attribute that to us thinking something is profound in a dream state, but, once we regain our ability to think logically, we know it's just gibberish. Something similar happens to people on some drugs and alcohol: They think they are having profound thoughts, but, if they record them, they later realize they were total crap, once they sober up. StuRat (talk) 16:58, 6 April 2010 (UTC)

You may find a couple of our articles helpful. Take a look at Oneirology and Dream. 10draftsdeep (talk) 18:33, 6 April 2010 (UTC)

The term I've seen used is "dream amnesia" -- things that happen in dreams make it into short term memory but aren't consolidated into long term memory unless they receive attention shortly after awakening. The sense of familiarity is probably related to the tip of the tongue effect, and perhaps to Déjà vu. Looie496 (talk) 23:48, 6 April 2010 (UTC)

Thymus vulgaris

Is Thymus vulgaris an annual? Googlemeister (talk) 18:30, 6 April 2010 (UTC)

This site [24] says it's an evergreen. I've never been able to grow it more than about 2 years though. By the way, the picture in our article looks more like Rosemary (Rosmarinus officinalis) to me. --TammyMoet (talk) 18:42, 6 April 2010 (UTC)

I would call it (or WP calls it ) a Subshrub; err... so No I don't think so as it survives the winter. --Aspro (talk) 18:44, 6 April 2010 (UTC)

Did you read the article you linked to? It seems to contradict you - the second paragraph says the woody stem overwinters. --Tango (talk) 01:32, 7 April 2010 (UTC)

This site calls it a perennial: [25]. StuRat (talk) 18:47, 6 April 2010 (UTC)

Another factoid for discussion...

'Whenever it has been established that a bird possesses the ability to count, it can usually only count up to as far as the number of eggs typically laid by its species per clutch, plus one'. I suppose that the wisdom behind this being that the only real use a bird has for counting objects is to determine if am egg has been taken or if nest parasite or another member of its species has laid an extra egg in its nest. Confirm/debunk?

I'm trying to tie this in to something my grandmother once told me about a chicken's ability to count as related to the number of 'foreign' (i.e. from another hen, or a duck - as is/was done 'down on the farm') eggs that can safely be placed in with her clutch without her freaking out. It was something along the lines of 'she only counts the first seven, so if she already has seven eggs, you can add more and she won't notice - but if she has six and you add a seventh, she'll abandon the whole lot or start destroying eggs' - but I may be remembering that wrong (long time ago now). --Kurt Shaped Box (talk) 18:48, 6 April 2010 (UTC)

Our article Bird intelligence claims some birds have been shown to be able to count up to 3, 6, or possibly 8. It warns birds may be subitizing and not truly counting. Comet Tuttle (talk) 19:31, 6 April 2010 (UTC)

This statement sounds a lot like the premise behind rabbit math in the novel Watership Down. The main character's name is "Hrairoo", which is translated into English as "Fiver"; he was some number past 4 in his litter, and rabbits can only count up to 4; all numbers past that are "Hrair", which means "more than 4". --Jayron32 20:20, 6 April 2010 (UTC)

what am I doing wrong with this acid base problem? (sodium acetate solution ==> acidic pH?)

I have NO idea why I'm getting an acidic pH. I have pure sodium acetate solution and there is no external source of H+ except for water.

Firstly, this is being conducted at 80 C, so K_w is modified to 1.5 * 10^-13. Which shouldn't be too much of a hiccup.

[H+] = 1.5 * 10^-13 / [OH-]

Relying on the approximation, [OH-] = [AcOH].

so K@353K = 8 * 10^-5 = [AcO-][H+] / [AcOH] = (0.1-x) * (1.5 * 10^-13 / [x]) /  (x)
= (1.5 * 10^-14  - (1.5/x) * 10^-13) / x = 1.5x^-1 * 10^-14 – 1.5x^-2 * 10^-13 = 8 * 10^-5  
0  = 8x^2 * 10^-5  - 1.5x * 10^-14  + 1.5 * 10^-13 
0 = 5.33x^2 * 10^8 – 0.1x + 1  
5.33x^2 * 10^8 = 0.1x – 1 (the last term is negligible) 
5.33 * 10^8 x = 0.1
0.1 / (5.33 * 10^8) = x =  1.876 * 10^-10  = [OH-] 
pOH = 9.7267 
pH = 12.824 – pOH = 3.097 

The 353K water makes it slightly more acidic, but I should still get an alkaline solution, right?

John Riemann Soong (talk) 21:53, 6 April 2010 (UTC)

It would help if you annotated your equations. I'm not sure exactly (it's been a while since I did this) but your issue might be that you set up the equation wrong initially. The sodium(Na+) and the acetate (AcO-) presumably dissociate completely leaving whatever your molar concentration is of acetate in solution. The acetate, being a weak acid, starts grubbing for protons from the water and establishes an equilibrium between acetate (AcO-) and acetic acid (AcOH) and OH-. I think your equation should be set up with AcOH and OH- on the top and AcO- and H₂O on the bottom. The pKb of acetate from sodium acetate is 9.25 btw. Hope someone will correct me if I am wrong... 152.16.15.144 (talk) 22:30, 6 April 2010 (UTC)

Well I kind of solved it a different way. (As in I found a correct answer another way.) But I'm using K_a, so I just modified the expression to use K_a. I defined H+ in terms OH-, and worked from there... I wonder why it doesn't work ... John Riemann Soong (talk) 23:46, 6 April 2010 (UTC)

do the effects of smoking ever go away? (smoking regular cigarettes like marlboros)

1. do the effects of smoking ever go away?
specifically, you see pictures of healthy nonsmoker's as contrasted with all charred up smoker's lungs; if somebody stops smoking (say, after 5-6 years of smoking from 19-25), then presumably their lungs are between the two. Would they get back to totally healthy after a number of years? Or would the blackened tar and stuff stay in their lungs for the rest of their lives?

2. besides the black tar, what other symptoms do smokers develop that might stay with them? (e.g. yellow teeth, wrinkles, and so on)

3. how much of specifically the lung effect is present for a second hand smoker? would this disappear after a number of years?

For someone who is not a smoker, but around smokers when they smoke, would the same lung effect be present? Would this disapear after a number of years if they were exclusively in nonsmoker areas?

Thank you very much. Note: I am not asking for medical advice. 82.113.106.35 (talk) 21:53, 6 April 2010 (UTC)

This site should help with your first question. I think passive smoking has the same effects as direct smoking, just reduced. How severe those effects will be will, of course, depend on the level of exposure. --Tango (talk) 22:04, 6 April 2010 (UTC)

I cannot speak about the effects to one's lungs, but studies show that the effects to one's periodontium (in terms of how smoking effects wound healing, etc. in periodontal disease, implant placement) take 11 years to become statistically insignificant. DRosenbach ^{(Talk | Contribs)} 03:53, 7 April 2010 (UTC)

ex=paratrooper with back problem been put on tramadol for 8 years.........

I'm sorry, but this appears to be a request for medical advice, which we cannot legally provide. Please ask your doctor for more information. —ShadowRanger ^(talk|stalk) 22:09, 6 April 2010 (UTC)

Actually, the concern is not that we "cannot legally provide" it; it is an ethical concern — what if we, anonymous people on the Internet, give you advice which you follow, and we're wrong, and your partner ends up screwing up his health more? You do need to consult a doctor about any medical advice, sorry. Comet Tuttle (talk) 22:48, 6 April 2010 (UTC)

Sodium bicarbonate

Is sodium from sodium bicarbonate (baking soda) as unhealthy as sodium from sodium chloride (salt)? --70.129.184.122 (talk) 22:12, 6 April 2010 (UTC)

Yes, insofar as when it reacts in your stomach, it produces NaCl, per this reaction diagram from the article:

NaHCO₃ + HCl → NaCl + H₂CO₃

H₂CO₃ → H₂O + CO₂(g)

The amount of sodium per gram will be less than the amount per gram of NaCl though. —ShadowRanger ^(talk|stalk) 22:15, 6 April 2010 (UTC)

Really, the Chloride doesn't matter at all: it's the Na⁺ ion that's bad for you, and the chloride's just along for the ride. Of course, baking soda does contain less sodium per mass (39% for salt vs. 27% for baking soda), and most people consume a lot less baking soda than they do salt. Buddy431 (talk) 00:00, 7 April 2010 (UTC)

However, eating elemental metallic sodium would be a very bad idea. StuRat (talk)

OUCH!!! 24.23.197.43 (talk) 01:28, 7 April 2010 (UTC)

Acid + metal reaction...very bad idea. ~AH1^(TCU) 02:59, 7 April 2010 (UTC)

Time and the Big Bang

Which frame of reference was chosen so that our recent estimations were considered? For instance, it took about less than 400,000 years for the decoupling event to have occurred after the Big Bang and the estimated age of the Universe is 13.75 billion years.--Email4mobile (talk) 22:32, 6 April 2010 (UTC)

I'm not sure what you're asking but it seems to me that the right answer to your question likely is the comoving frame with the galaxies. Read comoving coordinates. Dauto (talk) 02:28, 7 April 2010 (UTC)

discrepancies in attempting to isolate enthalpies/entropies of dissociation

At 293K, I am told the K_a for formic acid is 1.765 * 10^-4, but 1.768 * 10^-4 at 303K.

Using the simultaneous equations: ∆H – 293K*∆S = ∆G @ 293K = -R * 293K ln (1.765 * 10^-4) (21054 J/mol) ∆H – 303K*∆S = ∆G @ 303K = -R * 303K ln (1.768 * 10^-4) (21768 J/mol)

21054 J/mol – 21768 J/mol = -714 J/mol = (293-303)K * ∆S (714 J/mol / 10K) = 71.43 J/(mol*K) = ∆S

but, plugging back in: 21054 J/mol + 293K*71.43 (J/(mol*K)) = 41974 J/mol = ∆H and I get delta-H of 43400 J/mol at 303K. Uhhhh? John Riemann Soong (talk) 23:03, 6 April 2010 (UTC)

Try this instead. I am not sure what you did wrong, but if you reduce the simultaneous equations to a single equation, you should get

• ∆G₁ - ∆G₂ = (T₂ - T₁)∆S, or simpler
• ∆G₂₉₃ - ∆G₃₀₃ = (303-293)∆S or even simpler
• ∆G₂₉₃ - ∆G₃₀₃ = 10*∆S

I get ∆G₃₀₃ = 21756 J/mol, and ∆G₂₉₃ = 21042. Sub those in, and I get

• 21042 - 21756 = 10*∆S
• -714 = 10*∆S
• -71.4 J/molK = ∆S

Back to your initial two equations now,

• ∆G₂₉₃ = ∆H - 293*∆S
• 21042 = ∆H - 293*(-71.4)
• 21042 = ∆H - (-20920)
• 122 J/mol = ∆H

and for the other temperature

• ∆G₃₀₃ = ∆H - 303*∆S
• 21756 = ∆H - 303*(-71.4)
• 21756 = ∆H - (-21634)
• 122 J/mol = ∆H

Same answer. Near as I can tell, you dropped a - sign in your final step, so you added where you should have subtracted. BTW, I charge $40.00 per hour for this sort of tutoring, so this coupled with the amine-buffer help below would normally cost you some serious coin... --Jayron32 04:26, 7 April 2010 (UTC)

Health hazards from living near a busy road

Is there any information available about how dangerous it is to live x metres from a busy road, in terms of reduced longevity and so on? I'm thinking of the traffic fume pollution, such as the particulates and Polycyclic aromatic hydrocarbons, and how these may decline (or not) with distance from the traffic. Thanks. 92.29.111.79 (talk) 23:17, 6 April 2010 (UTC)

There are also claims that long term exposure to the noise of a busy road can have a deleterious effect. --Tango (talk) 23:21, 6 April 2010 (UTC)

A quick googl search (living near an road health) netted me these, among others: [26], [27], [28], etc. I'd say yes, there is information available, though I'm not sure you'll find a direct x meters to nearest road vs. mean lifespan graph anywhere. Buddy431 (talk) 00:54, 7 April 2010 (UTC)

There's also the possibility of being hit by a car, the stress caused by having cars whip by, and, if the road has been there a long time, an accumulation of lead and toxins in the soil near the road, which is a problem if food is grown there. StuRat (talk) 00:59, 7 April 2010 (UTC)

See also noise pollution. ~AH1^(TCU) 02:52, 7 April 2010 (UTC)

calculating the %protonation of amine in an ammonium acetate like salt...

I have 0.32M formic acid solution (K_a = 1.765 * 10^-4). I then add 0.2 equivalents sodium hydroxide. I then add 0.32M of an amine (K_b = 8 * 10^-3).

How do I calculate the %protonation of the amine?

My current work: The 0.32M formic acid solution + 0.2 equiv NaOH is calculated to have pH 3.3156. A- / AH = 0.2529; e.g. there is 0.06459 M formate anions and 0.2554 M formic acid.

Ka for formic acid = [H+][HCOO-] / [HCOOH]

Kb for amine = [OH-][RNH3+] / [RNH2]

Ka_acid * Kb_amine = Kw [HCOO-][RNH3+] / [RNH2][HCOOH]

Now I'm stuck. John Riemann Soong (talk) 23:44, 6 April 2010 (UTC)

Back up a bit. The formic acid/NaOH is just a buffer; I assume you used the Henderson-Hasselbalch equation to calculate the pH. At that pH, pOH = 14-3.3156 = 10.6048, so [OH-] = 10^-pOH = 2.48 * 10^-11.

	RNH2	+	H2O	-->	RNH3+	+	OH-
INITIAL	0.32		Ignore		0		2.48 * 10^-11
CHANGE	- x		Ignore		+ x		+ x
EQUILIBRIUM	0.32 - x		Ignore		x		2.48 * 10^-11 + x

Now, use the equation Kb = [RNH3+]*[OH-]/[RNH2], and subbing from the bottom line of the above table, you get 8 * 10^-3 = (x)*(2.48 * 10^-11 + x)/(0.32 - x). Solve for x. Plug the x value back into the bottom line of the above table to find the equilbrium concentrations of [RNH2] and [RNH3+], and % protonation is simply ratio of the equilibrium concentrations * 100, or [RNH3+]/[RNH2] * 100. I hope that made sense. This is much easier to teach when talking to someone in person... --Jayron32 03:57, 7 April 2010 (UTC)

April 7

Radio station reception

I'm not sure if this falls under technology or electronics, but if it is the latter, feel free to move this to the computing desk. One of my favorite radio stations is KFDI-FM out of Wichita, Kansas. Unfortunatly, I live in the vicinity of Salina, Kansas. This map shows the reception range of KFDI (at the range where Salina is, the reception could be classified as spotty at best). Here are the technical specifications of the station. What steps can I take to get better reception, perhaps by modifying a radio? Would a Broadcast relay station be a feasible step on the part of either the radio station or myself, considering that would allow this radio station to tap into an additional 55,000 people for it's market? In short, what ways (other than their online stream) could I attain reception of this station in Salina? Ks0stm ^(T•C•G) 01:06, 7 April 2010 (UTC)

A bigger, better, higher, directional antenna is the obvious answer. What type of antenna do you have now ? StuRat (talk) 01:03, 7 April 2010 (UTC)

I'm thinking of the type found on a vehicle so that I can get reception while driving. Ks0stm ^(T•C•G) 01:06, 7 April 2010 (UTC)

That isn't going to work, as you can't mount much of an antenna to a car. So, a rebroadcast relay station might be your only option. You could put a big antenna at your house, then rebroadcast from there, but you'd have to get the station and the FCC to agree, and good luck with that. StuRat (talk) 01:11, 7 April 2010 (UTC)

Also, that range map is rather iffy. The range is not usually completely circular like that. The two primary reasons are local geography, such as hills, and the signal being somewhat direction, when broadcast. StuRat (talk) 01:11, 7 April 2010 (UTC)

You say the range is not perfectly circular because of hills… Have you been to central Kansas? :-) —Bkell (talk) 02:48, 7 April 2010 (UTC)

I should also back up and ask why this station is so important ? Is there a particular program you just love ? Maybe there's some other way to access it. StuRat (talk) 01:13, 7 April 2010 (UTC)

The news and severe weather coverage is unparalleled, and for a severe weather fanatic like me, this makes the station very appealing. I like to monitor the station when there is severe weather to the South or southwest that may move towards Salina. Unfortunately, this is one of the times/situations it decides to offer its most spotty reception. Ks0stm ^(T•C•G) 02:05, 7 April 2010 (UTC)

Perhaps a weather radio would be in order ? StuRat (talk) 02:10, 7 April 2010 (UTC)

For news, perhaps the local NPR station, KHCD-FM, 89.5, might do. They aren't 24-hour news, but have frequent news, including in-depth stories. StuRat (talk) 02:20, 7 April 2010 (UTC)

This is probably not a practical option. But they have an option to listen on their web-site. What's the G3 covereage like in your area? You could theoretically listen on a mobile internet device like an iPhone.

(Be very carefull about monthly bandwidth caps and overage fees before trying this!) APL (talk) 04:18, 7 April 2010 (UTC)

A better antenna would be a good option. FM radio uses approximately the same frequency as VHF TV. So any good VHF (not UHF) TV antenna would also work for FM. In fact you may have a TV antenna on your roof already, and with a splitter you can get FM from it as well. There are a LOT of different kinds of antennas. I'm certain with a good antenna you could receive your station. A car would be tough, but even there you might be able to do something. For example a whip antenna tuned to exactly the frequency of your chosen station. After that any improvements (other than height) will also cause your antenna to become directional (to a greater or lesser extent depending on the antenna design). This may be tough in a car. The more directional the antenna the weaker a station you can receive, but also the harder it is to position it exactly right (plus it won't get other stations). Ariel. (talk) 05:47, 7 April 2010 (UTC)

acid rain/ fog

wouldn't fog contain more acid/impurities than rain? because its more concentrated/ has less water in it ?

Fog is not necessarily "more concentrated" than rain, it just contains smaller size droplets (which are therefore suspended in the air and don't fall to the ground). As for the amount of water, both of these form when humidity reaches saturation level, so the amount of water is the same. FWiW 24.23.197.43 (talk) 01:34, 7 April 2010 (UTC)

Fog is basically a ground-level cloud. Since rain comes from clouds - it's hard to imagine how there would be any difference in the impurity level. I suppose it's possible that rain might pick up impurities as it falls - but then we'd have to ask what the past history of cloud was. If there is a general answer, I'd guess that they would be about the same. SteveBaker (talk) 02:40, 7 April 2010 (UTC)

Acids in rain that cause acid rain usually forms dissolved compounds in the droplets such as nitric acid and carbonic acid. Impurities, or particulate matter, often forms condensation nuclei in the cloud. Since fog or cloud droplets are usually smaller than raindrops, as rain is the combination of many smaller droplets from condensation, it's possible that the minute amounts of acid or particulates in the droplets could combine and add up. However, according to acid rain, "Occasional pH readings in rain and fog water of well below 2.4 have been reported in industrialized areas" (acid fog is a red link). ~AH1^(TCU) 02:46, 7 April 2010 (UTC)

Salt Level in water to corrode metal

Hi Friend,

can you help me with this?

i am constructing a recycling water system for washing vehicle.

i need to know the dissolved salt level in the water that will corrode metal.

example: maybe 2000ppm and above will corrode metal.

so i will discharge all water and replace them before reaching 2000 ppm.

please assist.

Alex Singapore —Preceding unsigned comment added by Thocy (talk • contribs) 02:24, 7 April 2010 (UTC)

Salt corrodes iron by promoting ion exchange and redox reactions between the iron and the air/water. Therefore, any amount of any salt in the water will tend to accelerate corrosion to some extent. That said, the rate of corrosion is directly related to the concentration of salt in the water -- sea water will corrode iron pretty quickly, while tap water will cause only a negligible amount of corrosion (in the short run anyway). In short, there's no hard and fast threshold above which salt will corrode iron; the main rule to remember is, the less salt the better. FWiW 24.23.197.43 (talk) 02:37, 7 April 2010 (UTC)

Water will corrode iron even without any salt. Make your pipes out of a different metal. Aluminum if you can, but it's probably hard to get pipes. Copper is probably your best bet, it resists corrosion even with seawater, and it's easy to buy. Copper pipes come (in the US) in three different thicknesses, K, L, M. K is thickest, and you way want to spend a little extra and use it instead of a thinner one. You can also use plastic, PEX is a good choice for high temperature applications, also CPVC (not regular PVC). Ariel. (talk) 05:03, 7 April 2010 (UTC)

You can also protect your iron pipes via Cathodic protection, usually by using coated iron pipes; i.e. iron coated with aluminum, magnesium, or zinc, such that the more active metal is sacrificially corroded, protecting the iron. The lede of the Cathodic protection article specifically mentions protecting iron pipes as a common usage. --Jayron32 05:08, 7 April 2010 (UTC)

physics question

Alright I've been working on this one for such a long time, could someone please help me? Two steel balls are suspended on 1.50 meter long strings of negligible mass. The first mass is released from rest from an angle of 40.0o and collides perfectly elastically with the larger mass which was originally at rest. To what maximum angle will the larger ball rise after the collision? The answer is 26.4 degrees but im wondering what to use like conservation of energy, momentum or something else. Thanks for your help. 198.188.150.134 (talk) 07:50, 7 April 2010 (UTC)