Wikipedia:Reference desk/Archives/Science/2011 July 5
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July 5
[edit]Hello, looking for a book
[edit]I search a rich-in-colored-images book about the physiology of the 5 senses. a book that will show almost in every relevant page; rich & informative illustrations about the physiology of those. the reason i ask U guys is because this books are very expensive (more than 120 $), they many times got more then 1000 pages, plus; i have only basic knowledge in the issue and the reason i need such a book is to learn stage by stage, mostly by Re-drawing the informative illustrations in this books.
Thanks, Ben. — Preceding unsigned comment added by 109.67.3.117 (talk) 00:21, 5 July 2011 (UTC)
- Suggestion: 1. Go to amazon.com or other book sources like Worldcat.org. 2. Search for the titles of the expensive books you saw. 3. The page should give you suggestions for similar books, there may be some that are less expensive. --George100 (talk) 10:43, 5 July 2011 (UTC)
- Also note: Worldcat can determine if a nearby library has the book, if you enter your location (although many countries don't have this feature). --George100 (talk) 14:05, 5 July 2011 (UTC)
Calling all cell molecular biologists and/or biochemists. Article merge needs help
[edit]Just a request for an RDS regulars who have a little expertise in cell molcular biology and/or biochemistry and could help out with an article merge. There is a stubby orphaned article at IL-12 and IL-12 Receptor β1 Mutations which would probably do better as a subsection of the main article, which I think is Interleukin 12 but I don't know enough about the topic to actually make the merge properly. See Talk:Interleukin 12 for a little more discussion on the issue. I have also notified Wikipedia:WikiProject Molecular and Cellular Biology, but not knowing how active the project is, I thought I would pitch this out for anyone here to help if they were so inclined. --Jayron32 01:02, 5 July 2011 (UTC)
Biological trait
[edit]Is there a website where I can learn about biological traits? like for example brown-eye brunette man marries a blue-eye blonde woman and they have two boys and two girls. The brunette boy and the brunette had brown eyes like the man and the blonde boy and the blonde girl has blue eyes like the woman. Would it be possible for a blonde boy to have brown eyes and the brunette boy have blue eyes and blonde girl with brown eyes and brunette girl with blue eyes? Also, which eye colour do black hair and red hair usually tend to have the most? — Preceding unsigned comment added by 70.53.229.36 (talk) 01:52, 5 July 2011 (UTC)
- Try Eye color which discusses the genetics and Human hair color which also discusses genetics. --Jayron32 02:01, 5 July 2011 (UTC)
movie of semen into vagina
[edit]I know this may sound porn but I am serious about semen into the woman's vagina in closeup view? what about penis penetrating into the woman's anus in closeup view?—Preceding unsigned comment added by 70.53.229.36 (talk) 01:54, 5 July 2011
- Try Google. ~ Mesoderm (talk) 01:56, 5 July 2011 (UTC)
- You are right - it does sound like porn. And you sound like a troll. Go somewhere else. Dolphin (t) 02:03, 5 July 2011 (UTC)
- Such video footage (inside the vagina) has been shown as part of a series on sex on Public Television in the US years ago, likely in the 1990s. I don't recall the name of the series. Edison (talk) 02:12, 5 July 2011 (UTC)
- Video footage of ejaculation from inside the vagina was shown on The Miracle of Life on PBS in the united states, which is the TV show you are likely thinking of (unbelievably, this is a redlink, but the show was fairly notable in its day). It was a 1983 episode of Nova, and won an Emmy according to our article on Nova. The video is widely availible for purchase in many formats at Amazon and other sites. As far as penises entering anuses, such videos are so prevalent on the intrewebz, I don't think the OP needs any help finding thos.e --Jayron32 02:25, 5 July 2011 (UTC)
- Yes, and I think it was black-and-white and looked not much different from a sonogram. Educational but not especially lascivious. National Geographic is more pornographic than that. ←Baseball Bugs What's up, Doc? carrots→ 11:32, 5 July 2011 (UTC)
- Video footage of ejaculation from inside the vagina was shown on The Miracle of Life on PBS in the united states, which is the TV show you are likely thinking of (unbelievably, this is a redlink, but the show was fairly notable in its day). It was a 1983 episode of Nova, and won an Emmy according to our article on Nova. The video is widely availible for purchase in many formats at Amazon and other sites. As far as penises entering anuses, such videos are so prevalent on the intrewebz, I don't think the OP needs any help finding thos.e --Jayron32 02:25, 5 July 2011 (UTC)
- Such video footage (inside the vagina) has been shown as part of a series on sex on Public Television in the US years ago, likely in the 1990s. I don't recall the name of the series. Edison (talk) 02:12, 5 July 2011 (UTC)
- You are right - it does sound like porn. And you sound like a troll. Go somewhere else. Dolphin (t) 02:03, 5 July 2011 (UTC)
- a search by with the term 'cream pie' might help --helohe (talk) 10:29, 5 July 2011 (UTC)
- We have an article: Creampie (sexual act). And thank you Jayron for the info. I'd seen that footage years ago but wondered where I'd seen it. Not that I need to know but now at least I can put a name with the memory in my brain. --Dismas|(talk) 10:37, 5 July 2011 (UTC)
- Wikimedia Commons has a number of video resources pertaining to ejaculation, but alas, so far our contributors have not figured out a way to watch semen inside the vagina or uterus with an endoscope. I imagine that the living liquid still knows a few undiscovered tricks not readily apparent outside its favored running track. Wnt (talk) 15:20, 5 July 2011 (UTC)
- We have an article: Creampie (sexual act). And thank you Jayron for the info. I'd seen that footage years ago but wondered where I'd seen it. Not that I need to know but now at least I can put a name with the memory in my brain. --Dismas|(talk) 10:37, 5 July 2011 (UTC)
Gradient of potential energy
[edit]If two point-particles interact with one another, there will be a potential energy function associated with the interaction. Now the (negative of the) gradient of this function is supposed to give the force...but the force on particle 1 or on particle 2? It can't give both, because the gradient of a field is unique, but how can it distinguish between 1 or 2? 74.15.136.219 (talk) 02:13, 5 July 2011 (UTC)
- The force on each particle is identical. See Newton's third law. --Jayron32 02:20, 5 July 2011 (UTC)
- Newton's Third Law of Motion states that if one body exerts a force F on another body, the other body exerts the same force F on the original body. The forces act in opposite direction, but their magnitudes are the same. Dolphin (t) 02:25, 5 July 2011 (UTC)
- Those statements are correct assuming that the only forces arise from the interaction between the two particles. More generally, if you have two particles, the potential energy is a function of two variables (representing the positions of the two particles), and the force on each particle is proportional to the partial derivative of the potential with respect to its position. Looie496 (talk) 02:28, 5 July 2011 (UTC)
But the force on particle 1 is not the same as the force on particle 2. They're pointing in opposite directions.
I'll give a concrete example. Suppose particle 1 is at the origin, and particle 2 is at a position [x,y,z]. The interaction between the two is the Gravitational force. So, U(r) = -Gm1m2/r. So -∇U = Gm1m2∇(1/r). r = √x^2 + y^2 + z^2, so after some derivatives, I get that -∇U = -Gm1m2/r^3 * r. Now, I know physically that this is the force on particle 2, because the force on particle 1 would be Gm1m2/r^3 * r. But how should I know this mathematically? 74.15.136.219 (talk) 02:42, 5 July 2011 (UTC)
- Because you have to define a direction and keep it consistent throughout your equations. The force on one will be positive and the other will be negative; thus, opposite directions. -RunningOnBrains(talk) 02:48, 5 July 2011 (UTC)
- Where did I define a direction? 74.15.136.219 (talk) 02:52, 5 July 2011 (UTC)
- In your equations, you have written the unit vector "r". This vector holds the direction of the force; in the equations as you have written them, it points towards the center of mass of one of the particles. You may ask, "Which one?" Answer: it doesn't matter! If you choose it to be towards the center of mass of the first particle, then the force on particle 1 will be positive in the "r"-direction and the force on particle 2 will be negative in the "r"-direction. If you choose it to be towards the center of mass of the second particle, then the force on particle 1 will be negative in the "r"-direction and the force on particle 2 will be positive in the "r"-direction. These are physically identical situations, only different in the coordinate system we choose: both give the answer of equal and opposite forces on each particle. -RunningOnBrains(talk) 07:45, 5 July 2011 (UTC)
- The existance of two particles automatically defines a direction. If there are two particles, there is always a line connecting the two particles, and directions can exist relative to this line. In the simplest term, you can consider motion along this line such that the particles move closer together, or conversely farther apart. You can also define directions off the line, for example by defining motion relative to initial starting positions at angles to the line, or you can define an arbitrary coordinate system relative to the line (such that the origin is one of the particles and an axis lies along said line). However, direction automatically exists once you have multiple particles, and motion (and by extension force) just needs to be defined according to arbitrary convention; certain concepts like "towards" and "away from" will be absolutely defined, but other concepts like "negative" or "positive" will need to be defined by the coordinates you choose. --Jayron32 02:57, 5 July 2011 (UTC)
- Where did I define a direction? 74.15.136.219 (talk) 02:52, 5 July 2011 (UTC)
- As Looie said, the potential is a function of the positions of both particles (six real variables), and the force on one is the partial derivative with respect to its coordinates. We may as well choose coordinates such that both particles lie on the x axis, in which case the potential is U(x1, x2) = −K/(x2−x1) where K = Gm1m2 (assuming x2 > x1). Then −∂U/∂x1 = K/(x2−x1)² and −∂U/∂x2 = −K/(x2−x1)², so the forces on particles 1 and 2 are in the +x and −x directions respectively. -- BenRG (talk) 03:16, 5 July 2011 (UTC)
Ah, great, thanks. Quick question that's not all that related: when is ∂/∂(x1 - x2) = ∂/∂x1? I suspect always, but I can't prove it. 74.15.136.219 (talk) 03:38, 5 July 2011 (UTC)Nevermind, it's obvious now...I need sleep. 74.15.136.219 (talk) 03:56, 5 July 2011 (UTC)
Hospital double doors
[edit]Why do hospital double doors (at least, the ones that I've seen) always open the opposite way from each other (that is, one inward and one outward, instead of both inward or both outward)? —SeekingAnswers (reply) 07:30, 5 July 2011 (UTC)
To clarify, I'm asking about side-by-side doors, not two doors in succession down a short hallway. —SeekingAnswers (reply) 04:43, 7 July 2011 (UTC)
- so wHeelchair users can open them? (don't seem to have a tilde key on this iPad)
- — Preceding unsigned comment added by Robinh (talk • contribs) 03:34, 5 July 2011
- The tilde key is two levels down but is on an iPad's keyboard. When you're on the regular keyboard, tap the button for numbers and special characters. Then tap the second button labeled "#+=" for additional special characters. The tilde is in the middle of this keyboard. Dismas|(talk) 12:47, 5 July 2011 (UTC)
- You can also use the "quick sign" link in the Wikipedia edit page; below the text-entry box is an "insert" box with a variety of MediaWiki-syntax hotlinks. Nimur (talk) 14:54, 5 July 2011 (UTC)
- thanks guys. Robinh (talk) 09:49, 7 July 2011 (UTC) and indeed Robinh (talk) 09:49, 7 July 2011 (UTC)
- You can also use the "quick sign" link in the Wikipedia edit page; below the text-entry box is an "insert" box with a variety of MediaWiki-syntax hotlinks. Nimur (talk) 14:54, 5 July 2011 (UTC)
- Hospital doors (and the doors to restaurant kitchens) frequently have hinges that will allow the door to swing either way, and that are hung (or spirally sprung) so the door settles back at the closed position once it's released. This arrangement allows wide objects (or groups) like a cage-cart or a medical team with a gurney to push both doors, allowing quick access. For individual people (who seem to intuitively follow that country's drive-on-the-left/right rule, even when walking), those walking in opposing directions can both push their door, giving the inward/outward pattern you've observed. In a hospital there's an additional benefit to always being able to push a door - you can push a door with your foot or bum or shoulder (to pull you need your hand); that reduces the opportunities for microorganisms to be transferred between people via doors. -- Finlay McWalter ☻ Talk 11:03, 5 July 2011 (UTC)
- It's quite common for restaurant kitchens to have 2 doors - one that only opens outwards and one that only opens inwards. That way the waiting staff can hold plates and back through the door, safe in the knowledge that no-one can be coming the other way.--Phil Holmes (talk) 13:14, 5 July 2011 (UTC)
- Thanks for linking 'hospital' and 'door'. I think we're all clear on what we are trying to understand. Caesar's Daddy (talk) 14:06, 5 July 2011 (UTC)
- I'm still unclear on this "open" concept you speak of. :-) StuRat (talk) 01:33, 6 July 2011 (UTC)
- Haha! DRosenbach (Talk | Contribs) 01:16, 6 July 2011 (UTC)
- My work takes me to a number of hospitals in the UK and I have never encountered doors as you decribe, one leaf opening one way and the other leaf opening in the opposite direction. Sounds bizzare. Do they have instructions or arrows to indicate which way they open, if they do then it is clearly a method of avoiding collisions, if they don't have indicators then, jeez! someone needs to get the door fitters back. Richard Avery (talk) 14:12, 5 July 2011 (UTC)
- You're probably seeing double-egress fire doors. Hospitals are extensively subdivided by fire walls to allow patients to be evacuated from one part into another in case of a fire or smoke condition, rather than out into the street. Doors must be arranged to swing outward in the direction of egress. If there is a choice of directions, as commonly exists at a fire wall (you could go either way), then one door swings one way and the other door the other way. This kind of door is fairly normal in any really large building. Not only am I an architect, but I'm sitting in a hospital right now. I bet there's a set of these doors down the hall. Acroterion (talk) 15:16, 5 July 2011 (UTC)
- As I suspected, they're all over the place here: one almost got me just now when it started to close unexpectedly. Acroterion (talk) 16:25, 5 July 2011 (UTC)
Raw food
[edit]Why is it okay to eat raw fruit and vegetables if it is a bad idea to eat raw meat? —SeekingAnswers (reply) 07:36, 5 July 2011 (UTC)
- Why is it a bad idea to eat raw meat? Do those ideas apply to fruits and vegetables? Given the recent outbreaks of illness claimed to be caused by contaminated fruits or vegetables, are you sure the first part is true? DMacks (talk) 07:41, 5 July 2011 (UTC)
- I'm not sure why you're answering a question with a question but I tend to think that the OP is asking in a general sense. Fruits and vegetables are often eaten raw and the opposite is true of meats. Any e. coli outbreaks that you may be thinking of are more the exception than the rule. Dismas|(talk) 10:40, 5 July 2011 (UTC)
- I was hoping to get the questioner to begin a compare/contrast of the two sets (maybe my response came off as too naive?). Indeed the issues are general, but they really all do come down to "what are the problems with raw meat?" ("pathogens" probably is high on that list) and whether they are a serious concern also for most plant-based foods ("no", with various reasons why). DMacks (talk) 10:48, 5 July 2011 (UTC)
- Listing those "various reasons why" would be helpful. —SeekingAnswers (reply) 16:23, 5 July 2011 (UTC)
- I was hoping to get the questioner to begin a compare/contrast of the two sets (maybe my response came off as too naive?). Indeed the issues are general, but they really all do come down to "what are the problems with raw meat?" ("pathogens" probably is high on that list) and whether they are a serious concern also for most plant-based foods ("no", with various reasons why). DMacks (talk) 10:48, 5 July 2011 (UTC)
- I'm not sure why you're answering a question with a question but I tend to think that the OP is asking in a general sense. Fruits and vegetables are often eaten raw and the opposite is true of meats. Any e. coli outbreaks that you may be thinking of are more the exception than the rule. Dismas|(talk) 10:40, 5 July 2011 (UTC)
- Interesting question. What I have been told before is that things like steak have few bacteria because the insides of say, a cow, do not naturally have a lot of bacteria. It's processed products which take bacteria in the packing environment into the insides of things which are more likely to cause infection. This makes sense because every year it is always sausages and burgers that are mentioned with regards to barbecues and food poisoning. Fresh fruit and veg aren't processed in the same way, and are washed to remove those on the outside. There's also (I believe) a shorter time-to-table for fruit; certainly, fruit people boast about how little time ago your lettuce was still growing in the field. Maybe this gives less time for bacteria to multiply, I'm not sure. Grandiose (me, talk, contribs) 10:47, 5 July 2011 (UTC)
- Also see Steak tartare, Carpaccio, Mett, and Sashimi. And if you want to be particular, prosciutto crudo and beef jerky is also "raw", or at least uncooked. --Stephan Schulz (talk) 11:10, 5 July 2011 (UTC)
- Bacteria, viruses and pathogens that infect plants typically don't infect animals or humans - the biology is just too different. However, despite the vast difference in appearance, cows, pigs, chickens and humans are all very much the same on the cellular level, so bacteria, to a lesser extent viruses, and other pathogens which infect animals can also infect humans. That's why you thoroughly cook chicken, ground beef and pork - to kill off the bacteria and other pathogens which were (potentially) living in/on the animal. While the inside of any healthy animal is usually pathogen free (exceptions for things like trichonosis, etc.) slaughtering an animal is a messy business, and bacteria/pathogens from the skin or the digestive tract can get transferred to the meat. (If you're careful about which animal you butcher and how you do it, you can often get away with raw meat - e.g. tartare, etc.) You don't have to worry so much about carrot pathogens - the main disease concern from vegetables is if pathogen-tainted animal manure gets on it. -- 174.31.196.47 (talk) 15:24, 5 July 2011 (UTC)
- Basically two reasons. First, raw meat is hard to chew and hard to digest -- cooking breaks down the membranes and allows digestive juices better access. Second, the same things that make meat nutritious to people make it nutritious to many microorganisms, which therefore grow much more vigorously on meat than on fruits and vegetables. Looie496 (talk) 16:28, 5 July 2011 (UTC)
- I buy the first reason (although there are other ways to soften up meat besides cooking), but not the second. Fruits and veggies get plenty moldy. It's just that, as noted above, a small amount of fruit mold, unlike a small amount of meat mold, won't hurt you, because it's not the kind of micro-organisms that infect humans. A large amount could harm you, but then you could tell it was rotten and avoid it. StuRat (talk) 01:40, 6 July 2011 (UTC)
- If any part of a fruit or vegetable is moldy you should discard all of it, not just chop the rotten part off, as the natural but harmful carcinogenic mold-chemical will already have spread through most of it. I was trying to find the article written by a scientist in Spiked magazine that describes this, but have not been able to. 92.29.118.212 (talk) 14:37, 6 July 2011 (UTC)
- While I agree with your advice I don't think it's so much that mycotoxins spread themselves. More that the visible portion of the mold is only just the tip of the iceberg. If you find any visible mold colonies, there will usually be a lot of mold that you can't really see. Look at [1] for example. Not what most people would consider fruits or veges but for cereals, seeds and nuts (peanuts and peanut butter are a common concern) aflatoxin is one of the headline mycotoxins. BTW re: another of StuRat's points, while mold (i.e. some types fungi) can be a concern on meat it's more cooked or cured/preserved meats, bacteria are generally the far bigger concern on raw meat. Nil Einne (talk) 19:00, 6 July 2011 (UTC)
- I agree that the mold will have spread much more than just the visible part. In addition, the mycotoxin will have diffused beyond the mold, both visible and invisible. I imagine the mycotoxin prepares the way for the invasion of the mold itself. 2.101.2.194 (talk) 10:46, 7 July 2011 (UTC)
- While I agree with your advice I don't think it's so much that mycotoxins spread themselves. More that the visible portion of the mold is only just the tip of the iceberg. If you find any visible mold colonies, there will usually be a lot of mold that you can't really see. Look at [1] for example. Not what most people would consider fruits or veges but for cereals, seeds and nuts (peanuts and peanut butter are a common concern) aflatoxin is one of the headline mycotoxins. BTW re: another of StuRat's points, while mold (i.e. some types fungi) can be a concern on meat it's more cooked or cured/preserved meats, bacteria are generally the far bigger concern on raw meat. Nil Einne (talk) 19:00, 6 July 2011 (UTC)
- If any part of a fruit or vegetable is moldy you should discard all of it, not just chop the rotten part off, as the natural but harmful carcinogenic mold-chemical will already have spread through most of it. I was trying to find the article written by a scientist in Spiked magazine that describes this, but have not been able to. 92.29.118.212 (talk) 14:37, 6 July 2011 (UTC)
- I buy the first reason (although there are other ways to soften up meat besides cooking), but not the second. Fruits and veggies get plenty moldy. It's just that, as noted above, a small amount of fruit mold, unlike a small amount of meat mold, won't hurt you, because it's not the kind of micro-organisms that infect humans. A large amount could harm you, but then you could tell it was rotten and avoid it. StuRat (talk) 01:40, 6 July 2011 (UTC)
solar wind temperature
[edit]can I ask anyone to say me about temperature of solar wind (energy per particle )please ?[for discussion only not homework ] A. mohammadzade IRAN --78.38.28.3 (talk) 08:32, 5 July 2011 (UTC)
- See Components under Solar wind. Plasmic Physics (talk) 08:45, 5 July 2011 (UTC)
- Also, because the solar wind is a sparse plasma, you may want to read or refresh your memory about a statistical definition of temperature, and also review some of the ways to define the temperature of a plasma. There are many species in the solar wind, and due to the low density, they weakly interact (in most scenarios). So, it's often useful to define a different temperature for, say, the electrons, the hydrogen ions, the helium He+, the helium He2+, and so on. Many researchers therefore call the solar wind a "non-thermal" or "non-thermal-equilibrium" plasma. Nimur (talk) 15:01, 5 July 2011 (UTC)
why is quantum mechanics weird?
[edit]why is quantum mechanics weird? why isn't it more intuitive, like things seem to work in real life (on a non-quantum level). Does this make it less likely to be true? --188.29.236.41 (talk) 10:39, 5 July 2011 (UTC)
- At any scale, things appear to work "differently" than at much closer or much further view. From far away, many details are lost, and if you "only" know the bigger picture, suddenly finding details that don't match what you know is confusing as heck. Quantum is especially weird to many folks because it is so specific and yet so specifically different than some things we have always absolutely known about everything. But it's just a really (really) detailed study that winds up in the same place as the big-picture approximation we usually use.
- For example, wave–particle duality seems silly...how can an object behave like a wave, diffract, and be in two places at once? We don't see normal visible objects doing that! Well first, all normal diffraction depends on wavelength and the dimensions of the slit through which it's diffracting. Now if you push the math of the diffraction for large objects, turns out the diffraction wavelength (and therefore the slit dimensions required to diffract it) aren't in the realm of anything we could observe. So the result of the wackiness is still that objects we see only appear to behave as objects (we don't see the wave-like property).
- How long did it take before people finally accepted what we currently know to be celestial motion? Sadly it's our understanding and experience that is limited, coupled with assuming everything fits patterns we easily see or expecting that the universe is governed by things that are completely simple. DMacks (talk) 10:58, 5 July 2011 (UTC)
- (ec)It appears to be "weird" because we evolved to interact with what is sometimes called "the Middle World", which exhibits certain properties we get used to and mistakenly assume to hold in general. No, this has negligible influence on the likelihood that it is a useful description of reality. "Truth" is a dangerous word in science - most scientific results are indeed false under a strictly logical interpretation, even though they are "close enough" for any imaginable purpose. --Stephan Schulz (talk) 10:59, 5 July 2011 (UTC)
- (ec back at ya!) Quantum itself is weird, likely weirder than we can possibly understand (can't remember which physicist said something that), but that's because we can't understand it. Even though science often looks for simple explanations and patterns, Nature wasn't designed to be understandable to humans:) DMacks (talk) 11:04, 5 July 2011 (UTC)
- Richard Feynman wrote "I think I can safely say that nobody understands quantum mechanics", and allegedly, "If you think you understand quantum mechanics, you don't understand quantum mechanics". Niels Bohr has said "Anyone who is not shocked by quantum theory has not understood it". --Stephan Schulz (talk) 11:20, 5 July 2011 (UTC)
- "I have no doubt that in reality the future will be vastly more surprising than anything I can imagine. Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose." -- J. B. S. Haldane -- CS Miller (talk) 11:41, 5 July 2011 (UTC)
- Richard Feynman wrote "I think I can safely say that nobody understands quantum mechanics", and allegedly, "If you think you understand quantum mechanics, you don't understand quantum mechanics". Niels Bohr has said "Anyone who is not shocked by quantum theory has not understood it". --Stephan Schulz (talk) 11:20, 5 July 2011 (UTC)
- I think fundamentally explaining why things appear to behave so differently on really small scales and really big scales is one of the things that a theory of everything would explain. Needless to say, they haven't got there yet. Maybe they will some day, maybe not. Grandiose (me, talk, contribs) 11:13, 5 July 2011 (UTC)
- (ec ec)The world is whooshing through space at high speed, but you can't feel it. Objects thrown fast enough away from it circle it and don't fall down. Apparently solid objects are in fact composed almost entirely of nothingness, with tiny invisible objects pushing and pulling at one another over relatively vast distances to manufacture the illusion of their solidity. Most of your ancestors were yoghurt. The gold in your wedding ring was made in massive exploding star, and 10% of the mass of your body was created by the big bang and has been unchanged since. The solid earth you walk on is but a skin on a boiling pudding of boiling rock. 8% of your DNA is viral rather than human, and almost all your cells need a captive bacterium to live. The world is incredibly older, celestial things are incredibly distant, and observable small objects are so incredibly tiny that they fly in the face of any sensible intuition about things. Your brain evolved to gather fruits and berries and to chase mammoths across the plain, and it's a wonder that it can be adapted so well to understand these ideas, which have very little to do with fruits and mammoths at all, so well. None of these things I've mentioned is intuitive; they're all crazy, really, and we've just gotten used to them. There's no reason to suppose the universe happens to be set up in a manner that we can understand, and it'd be a valid concern to worry that we may reach (or may have reached) points beyond which we're not intellectually able to understand things. So it may very well be that, like cows staring blankly at a passing aeroplane, we're just too stupid to properly understand the quantum world. -- Finlay McWalter ☻ Talk 11:20, 5 July 2011 (UTC)
- A religionist might say that quantum mechanics make perfect sense to God. :) ←Baseball Bugs What's up, Doc? carrots→ 11:34, 5 July 2011 (UTC)
Things in the real world do in fact work because of quantum mechanics, so it isn't that weird at all. A universe that works exactly according to classical mechanics would be much, much weirder than our universe. Count Iblis (talk) 15:30, 5 July 2011 (UTC)
- Take the analogy of someone building things from Leggo bricks and playing with the toys he has created from these. Over time, he gets to know a lot about how such toys work, how they are put together, how much they weigh, how they break up when you drop them. Now, suppose he gets an inside view into just one of those Leggo blocks. Suddenly, he sees it is a completely different world in there, with laws that do not apply to the toys he has created from these blocks. He realises that what he has always seen are is averages, what happens when lots and lost of these elemental blocks are put together. Perhaps, like a lot of sci-fi writers he might have assumed that the very small would just be another version of the very large. But it's not. The world inside a single Leggo block has many features that do not apply to the world we are familiar with. Similarly, the world INSIDE an atom is not like the world around us, which behaves as a gigantic average of countless numbers of these atoms, working in concert. But inside the atom, we see forces and events that have no correspondence to the macro world. That makes sense to me, even if I cannot understand quantum thoery. Earlier in the 19th Century (and even now) some people speculated that there was a world inside the atom which was kind of miniature world of our own. The idea of electrons orbiting a nucleus provided an irresistable analogy with the solar system, and some people took that literally. But it is not the case. The reality is a LOT more interesting than some infinite regression, where the smaller nested versions of the world behave much like the world itself. The "undiscovered countries" of the very small provide us with new laws, and new phenomena which we do not see on macro levels. Myles325a (talk) 05:30, 7 July 2011 (UTC)
Sun photo
[edit]Why pink spots are seen in photographs of sun? — Preceding unsigned comment added by 111Engo (talk • contribs) 12:19, 5 July 2011 (UTC)
- Sundog may be beneficial here. Dismas|(talk) 12:45, 5 July 2011 (UTC)
- It seems that camera gives photo from light in halo inside vacuum space , if sun had light look like leaser beam its photograph was look like any circle--Akbarmohammadzade (talk) 12:54, 5 July 2011 (UTC)
- I'm not exactly sure what you're trying to say, but this has nothing to do with halos, and has nothing to do with light reflecting or diffracting in outer space. This is reflection and/or refraction inside the camera itself; internal parts of the camera that are not specifically meant to do so (mirrors) are very non-reflective (as is necessary for taking high-quality photos), but if a bright enough light such as the sun is shined into the camera, this internal noise can be visible in the finished product.-RunningOnBrains(talk) 13:57, 5 July 2011 (UTC)
- Isn't it just lens flare? CS Miller (talk) 13:00, 5 July 2011 (UTC)
- Yes, it's lens flare. (It's definitely not sun dogs; the would appear white with colored fringes, not red, and they would not be arranged in the pattern seen here. The flares here are also too close to the sun to be dogs.) TenOfAllTrades(talk) 13:10, 5 July 2011 (UTC)
- Indeed, not only do sundogs appear at 22° separation from the sun, but they need to be on clouds, since ice clouds are what does the refracting. Definitely a lens flare or flare-like phenomenon involving reflection on the inner optics of the camera.-RunningOnBrains(talk) 13:53, 5 July 2011 (UTC)
- The clouds don't necessarily have to be conspicuous or even visible (either to the naked eye or in a photograph), however. You can get sun dogs with a very thin haze of ice crystals, if they happen to be in the right part of the sky. TenOfAllTrades(talk) 14:10, 5 July 2011 (UTC)
- Yes, but this looks very much like a six-petal red lens flare, characteristic of a cell-phone camera. Such flares are typically due to internal reflection inside the camera module lens element; and poor filtering of non-visible light wavelengths (due to the use of poor-quality optical glass). Other types of lens flare can be created (and modified) by multielement lenses, or by camera irises, or by lens hoods; but this is pretty characteristic. Even lacking EXIF, an expert could still be able to positively identify the camera that shot this particular example-image. Nimur (talk) 15:16, 5 July 2011 (UTC)
- Indeed, not only do sundogs appear at 22° separation from the sun, but they need to be on clouds, since ice clouds are what does the refracting. Definitely a lens flare or flare-like phenomenon involving reflection on the inner optics of the camera.-RunningOnBrains(talk) 13:53, 5 July 2011 (UTC)
- Yes, it's lens flare. (It's definitely not sun dogs; the would appear white with colored fringes, not red, and they would not be arranged in the pattern seen here. The flares here are also too close to the sun to be dogs.) TenOfAllTrades(talk) 13:10, 5 July 2011 (UTC)
- It is definitely lens flare, and the colors are caused by chromatic aberration inside the lens.Zzubnik (talk) 08:36, 6 July 2011 (UTC)
- The pink blotches aren't caused by chromatic aberration; CA is a specific image defect caused by slight differences in the refractive index of the lenses at different wavelengths, and would appear as colored 'fringes' around bright points in the image (our article shows several good examples). The blotches are the result of reflections off of the lens surfaces within the camera's optics; the color of the flares is governed by the choice of lens materials and (particularly) the types of antireflection coatings applied to them. TenOfAllTrades(talk) 01:55, 7 July 2011 (UTC)
- My mistake. I presumed abberation is what was causing the light to become colored. Thanks for the clarification. Zzubnik (talk) 08:48, 7 July 2011 (UTC)
- The pink blotches aren't caused by chromatic aberration; CA is a specific image defect caused by slight differences in the refractive index of the lenses at different wavelengths, and would appear as colored 'fringes' around bright points in the image (our article shows several good examples). The blotches are the result of reflections off of the lens surfaces within the camera's optics; the color of the flares is governed by the choice of lens materials and (particularly) the types of antireflection coatings applied to them. TenOfAllTrades(talk) 01:55, 7 July 2011 (UTC)
- It is definitely lens flare, and the colors are caused by chromatic aberration inside the lens.Zzubnik (talk) 08:36, 6 July 2011 (UTC)
Does the number of radiating spokes correspond to the number of blades of the camera's Iris (diaphragm)? Cuddlyable3 (talk) 09:31, 7 July 2011 (UTC)
- It depends on the root-cause of the lens flare. You may also find our article, bokeh, helpful. Both bokeh and lens-flare are, in practice, highly dependent on the interactions between many different optical interferences: imperfections in the glass; shape of the aperture; shading effects from a lens hood; reflections off the optical system interior surface; and reflections and refractions within the glass and lens elements. Bokeh tends to be a bit more intuitive: a de-focused point of light in the image blurs into a bokeh that is the shape of the iris. Photographers use this for artistic effect. In fact, you can buy "aperture foils" to create kitty-cat-shaped bokehs, pumpkin-shaped bokehs, and so on. In practice, lens flare usually does not have such a straightforward correspondence with the aperture shape, because it usually involves multiple bounces of light. Nimur (talk) 21:12, 8 July 2011 (UTC)
- When the spokes are seen on an on-axis image, what other than a non-circular aperture can determine the angle of the spokes? Cuddlyable3 (talk) 08:26, 9 July 2011 (UTC)
Watching TV in the dark
[edit]Is it bad for your eyes? And what about other screens, like a computer screen or a movie theater screen?Quest09 (talk) 12:27, 5 July 2011 (UTC)
- Why would it be bad for your eyes? Dauto (talk) 15:24, 5 July 2011 (UTC)
- Mom's said that. Could she be wrong? Quest09 (talk) 20:28, 5 July 2011 (UTC)
- Here's a responsible, well-researched article: Television and Health (1961). While the article was published half a century ago, it's thorough, and puts the various health-effects of television in perspective. According to the paper's author, eye-strain is attributable to glare more than any other effect; so, poorly-placed bright lighting is worse than a dark room. Nimur (talk) 15:55, 5 July 2011 (UTC)
- The British and US governments still advise people to avoid glare (light reflected from a screen) [6][7]. The American OSHA also warns against too-bright light, which can cause washed-out and hard-to-read images that lead to eye fatigue.[8] Doesn't seem to be anything about darkness. --Colapeninsula (talk) 12:32, 6 July 2011 (UTC)
- Mothers are never wrong. Your Eye is not designed for constant staring at a small bright image that illuminates only the yellow spot (macula). The Afterimage effect demonstrates the vulnerability of the retina to exhaustion. Therefore take a pause from screen viewing every hour, or more often if you sense tired eyes. Use the pause to scan across a distant view such as the landscape outside. A screen image with adequate brightness and contrast for daytime viewing is probably too bright for use in total darkness. Adjust the contrast and brightness controls for relaxed viewing. Cuddlyable3 (talk) 09:23, 7 July 2011 (UTC)
- The British and US governments still advise people to avoid glare (light reflected from a screen) [6][7]. The American OSHA also warns against too-bright light, which can cause washed-out and hard-to-read images that lead to eye fatigue.[8] Doesn't seem to be anything about darkness. --Colapeninsula (talk) 12:32, 6 July 2011 (UTC)
Equations
[edit]Hello I need help on the following scientific equations as I do not know all the products that is formed.
♦ CO2 + H2O → ?
♦ CO + H2O → ?
♦ SO + H2O → ?
♦ Hydrocarbon + H2O → ?
Please give me the simplest equation. Thank You — Preceding unsigned comment added by 41.14.215.113 (talk) 12:57, 5 July 2011 (UTC)
- This is presumably a homework question. You can find some of the answers at acid rain. Grandiose (me, talk, contribs) 13:15, 5 July 2011 (UTC)
- It's also a duplicate of this question above: Wikipedia:Reference_desk/Science#Nitrogen_oxide.2C_Carbon_dioxide.2C_Sulfur_Oxide.2C_Hydrocarbon; except that this time it uses diamond suit instead of spade. – b_jonas 19:58, 5 July 2011 (UTC)
I don't know what this is, but might as well say what can be said: CO2= carbon dioxide which forms carbonic acid in water, CO = carbon monoxide, SO = sulfur monoxide, and hydrocarbons can be pretty much anything with CxHx in them. I'm not familiar with any strong reactions with water except for the first, but one journal someone else should readily be able to access gives a Google blurb "Sulfur monoxide reacts with water at OD to form hydrogen sulfide, sulfurous acid, and sulfur".[9] It sounds plausible. Note that carbon monoxide (water gas) can actually be produced from water (in the form of steam) when it passes over carbon, so I really doubt it reacts further with water. Wnt (talk) 21:35, 5 July 2011 (UTC)
- Actually, Carbon monoxide can react with water, in the appropriately named Water gas shift reaction. Buddy431 (talk) 04:28, 6 July 2011 (UTC)
- This does not happen at STP, however:
- I think that carbon monoxide should be quite stable in solution, but if it does react the first point of attack should be the carbon atom. This should form a formyl and a hydroxyl radical, this in turn, reacts to form a formic acid molecule. According to classical thinking, carbonous acid is known as carbonous hydrate or hydrate of carbon monoxide, but this not formed as carbonous acid is highly unstable in solution. It is even known that carbonous acid is a protomer of formic acid in the gas phase. Plasmic Physics (talk) 14:00, 25 May 2011 (UTC)
Tree Falling
[edit]Hello I would like to have some help on this difficult equation for for my science project. If a tree falls in Knysna woods in South-Africa,Western Cape at the co-ordinates : 34°02`00.00"S 23°04`00,00"E will it make a sound if there is no one to hear it? ♦The tree is a Knysna Yellowwood, ♦The branches is reddish-yellow ♦The tree is falling at 5 metres per second, ♦At a angle of 45° ♦A mildly breeze of 7knots is blowing from the west ♦The tree is falling North-South
Please help me. — Preceding unsigned comment added by 41.14.215.113 (talk) 13:13, 5 July 2011 (UTC)
- If a tree falls in a forest should answer your question (I'm assuming good faith, but it's straining). Grandiose (me, talk, contribs) 13:17, 5 July 2011 (UTC)
- You could design an experiment to investigate it, using a pencil, a mechanism to make the pencil fall when you are outside the room, and a video camera. What do you think the result will be? Will the experiment be valid if you aren't in the room but your video camera is? Itsmejudith (talk) 14:53, 5 July 2011 (UTC)
- I'm disappointed that the article has no QM discussion. The trick with this sentence is the word "hear", as sound carries in many ways - such as alteration of weather by the butterfly effect. A tree on an island will fall or not, but a tree in a true Schroedinger's Cat grade "box" exists in a superposition of states. One comes to that island and determines, on opening the box, that a tree has fallen; hence it must have made a sound, you'd think - but if the sound is such to dissipate in a finite time, there may be no evidence of it when the tree finally is determined to have fallen. Yet when the tree actually fell the sound was cancelled out in the superposition of states by all the other out-of-phase sounds of the tree falling a moment sooner or later. Wnt (talk) 15:11, 5 July 2011 (UTC)
- I disagree with your last point that the superposition means that the sound was cancelled out. The superposition you get here involves the sound being entangled with many other degrees of freedom. It's then not a coherent superposition in which you only have to add up the amplitudes of the sound. Count Iblis (talk) 17:12, 5 July 2011 (UTC)
- To be honest? I still haven't quite figured that out. And I'm still thinking that if you had some observation device to measure pressure at one point within a large number of such tree-boxes as the sound (might be) being made, there would be no overall difference in probability of a high or low result at any point; hence no pressure waves exist... Wnt (talk) 17:56, 7 July 2011 (UTC)
- I disagree with your last point that the superposition means that the sound was cancelled out. The superposition you get here involves the sound being entangled with many other degrees of freedom. It's then not a coherent superposition in which you only have to add up the amplitudes of the sound. Count Iblis (talk) 17:12, 5 July 2011 (UTC)
- I'm disappointed that the article has no QM discussion. The trick with this sentence is the word "hear", as sound carries in many ways - such as alteration of weather by the butterfly effect. A tree on an island will fall or not, but a tree in a true Schroedinger's Cat grade "box" exists in a superposition of states. One comes to that island and determines, on opening the box, that a tree has fallen; hence it must have made a sound, you'd think - but if the sound is such to dissipate in a finite time, there may be no evidence of it when the tree finally is determined to have fallen. Yet when the tree actually fell the sound was cancelled out in the superposition of states by all the other out-of-phase sounds of the tree falling a moment sooner or later. Wnt (talk) 15:11, 5 July 2011 (UTC)
- You could design an experiment to investigate it, using a pencil, a mechanism to make the pencil fall when you are outside the room, and a video camera. What do you think the result will be? Will the experiment be valid if you aren't in the room but your video camera is? Itsmejudith (talk) 14:53, 5 July 2011 (UTC)
You neglected to say how big the tree is. If it is a full-size Kynsna Yellowwood (Podocarpus latifolius), that's a huge tree, and somebody would surely hear it fall, since the nearest houses are only 200 meters away, up the hillside. Looie496 (talk) 17:26, 5 July 2011 (UTC)
- The OP asked "will it make a sound". Sound arises from sound waves, right? And those waves will be produced whether someone happens to be around or not. ←Baseball Bugs What's up, Doc? carrots→ 18:08, 5 July 2011 (UTC)
- You are defining "sound" as being the sound waves and not the mental process of turning those sound waves into something we call sound. Once you define what "sound" means, the question is easy to answer. But, you are changing the question by doing so. As it was asked, there was no definition for what "sound" means. -- kainaw™ 18:21, 5 July 2011 (UTC)
- Then he needs to restate the question more clearly. He also needs to explain what "no one" means. Does it mean no human being? Or no creature of any kind that is capable of hearing? ←Baseball Bugs What's up, Doc? carrots→ 18:26, 5 July 2011 (UTC)
- You are defining "sound" as being the sound waves and not the mental process of turning those sound waves into something we call sound. Once you define what "sound" means, the question is easy to answer. But, you are changing the question by doing so. As it was asked, there was no definition for what "sound" means. -- kainaw™ 18:21, 5 July 2011 (UTC)
- That is the entire point of the question. It cannot be answered because it is ambiguous. It is the same as "What is the sound of one hand clapping?" You have to define what clapping means. Is it the action of two palms striking one another? Is it the waving motion of an arm? For a scientific person, these are rather inane questions, but they are still very popular. -- kainaw™ 18:30, 5 July 2011 (UTC)
- Goddess only knows why. "How many angels can dance on the head of a pin?" There are two possible answers: (1) All of them; or (2) None of them. ←Baseball Bugs What's up, Doc? carrots→ 18:34, 5 July 2011 (UTC)
- You forgot one possibility: (3) Some of them.-RunningOnBrains(talk) 19:20, 5 July 2011 (UTC)
- Give the OP points for adding a lot of irrelevant detail to make it look more like a question. Next he'll be showing us the proof that 1 = 2. :) ←Baseball Bugs What's up, Doc? carrots→ 18:36, 5 July 2011 (UTC)
- EO says "to clap" originates from a Frissian (sp?) verb meaning "to beat". Hence the term "clapper" for the clanging thing in a bell - which of course won't clang unless there's something to clang against. ←Baseball Bugs What's up, Doc? carrots→ 18:42, 5 July 2011 (UTC)
- Or the old fallacy, "If an irrestible force is approaching an immovable object, what will happen?" The answer is that nothing will happen, because by definition those two entities cannot exist in the same universe. ←Baseball Bugs What's up, Doc? carrots→ 18:56, 5 July 2011 (UTC)
- Yes they can. I'm an immovable object and I encounter irrestible forces all the time. But irresistible forces, ah, they're another matter. -- Jack of Oz [your turn] 19:27, 5 July 2011 (UTC)
- Do you resist them? Or do they move you? ←Baseball Bugs What's up, Doc? carrots→ 20:05, 5 July 2011 (UTC)
- Iain Banks's answer is "The unstoppable force stops, the immovable object moves". But this depends on the question being formulated as "unstoppable" rather than "irresistable". Tevildo (talk) 22:23, 5 July 2011 (UTC)
- Then the force and the object weren't really unstoppable and immovable. Unless maybe they chose to stop and to move. ←Baseball Bugs What's up, Doc? carrots→ 06:37, 6 July 2011 (UTC)
- Iain Banks's answer is "The unstoppable force stops, the immovable object moves". But this depends on the question being formulated as "unstoppable" rather than "irresistable". Tevildo (talk) 22:23, 5 July 2011 (UTC)
- Do you resist them? Or do they move you? ←Baseball Bugs What's up, Doc? carrots→ 20:05, 5 July 2011 (UTC)
- Yes they can. I'm an immovable object and I encounter irrestible forces all the time. But irresistible forces, ah, they're another matter. -- Jack of Oz [your turn] 19:27, 5 July 2011 (UTC)
- Goddess only knows why. "How many angels can dance on the head of a pin?" There are two possible answers: (1) All of them; or (2) None of them. ←Baseball Bugs What's up, Doc? carrots→ 18:34, 5 July 2011 (UTC)
- That is the entire point of the question. It cannot be answered because it is ambiguous. It is the same as "What is the sound of one hand clapping?" You have to define what clapping means. Is it the action of two palms striking one another? Is it the waving motion of an arm? For a scientific person, these are rather inane questions, but they are still very popular. -- kainaw™ 18:30, 5 July 2011 (UTC)
(outdent) "The tree is falling at 5 metres per second, At a angle of 45°" This leaves the tree in the peculiar situation of falling at a constant speed and maintaining a constant angle. Was the tree dropped from a crane or a helicopter? Wanderer57 (talk) 05:11, 6 July 2011 (UTC)
- Is the answer that the tree hasn't hit the ground yet? So it hasn't yet made a sound (although a tree does make a lot of creaking and branches hitting other branches before the big crash comes).Itsmejudith (talk) 06:56, 6 July 2011 (UTC)
- That would explain why it's falling north-south rather then simply north or south (which would be the case if it was uprooted or broke) Nil Einne (talk) 07:10, 6 July 2011 (UTC)
This boils down to the philosophical discussion of "what is sound". Are vibrations in air molecules "sound" before an ear has heard them? — Preceding unsigned comment added by Zzubnik (talk • contribs) 08:48, 6 July 2011 (UTC)
- I class this as a troll question because it is an ornamented crib of the hoary old (1883) koan If a tree falls in a forest (a Wikipedia article) and I contend that it was never an equation for a science project. People are having such fun with it that I won't delete it. I had more fun with the variation "A stealth fighter plane crashes in a forest with no one around, does it make a sound?" to which my answer is "Yes then no.". Cuddlyable3 (talk) 09:04, 7 July 2011 (UTC)
Electron cyclotron resonance and tapping
[edit]An electron in a static and uniform magnetic field will move in a circle due to the Lorentz force then if a electromagnetic wave of the right frequency (the same as the electrons circular orbit frequency) then the electron would gain energy is their anyway for the electrons energy to be directly turned into electricity? — Preceding unsigned comment added by 82.38.96.241 (talk) 15:16, 5 July 2011 (UTC)
- There is no efficient way to extract large quantities of electric current from electron cyclotron motion. Strictly speaking, when you detect cyclotron frequency using a radio-receiver, your antenna is collecting electromagnetic energy and a current is being induced in the antenna; so "electricity is being produced." But the quantity of energy collected this way is tiny, compared to the amount needed to create the plasma in the first place. Nimur (talk) 16:59, 5 July 2011 (UTC)
- See Homopolar generator for a device that uses the Lorentz force to generate electricity, albeit from mechanical rather than electromagnetic energy. Tevildo (talk) 22:18, 5 July 2011 (UTC)
The Pineal Gland - do we have 2 of those?
[edit]it says in the Wiki article; "Its shape resembles a tiny pine cone (hence its name), and it is located near the centre of the brain, between the two hemispheres, tucked in a groove where the two rounded thalamic bodies join."
therefore i ask U guys. thanks. — Preceding unsigned comment added by 109.67.3.117 (talk) 15:46, 5 July 2011 (UTC)
- No, we only have one Pineal gland each. I can't see how you got that we have two from the quote you have given. --TammyMoet (talk) 15:58, 5 July 2011 (UTC)
- Let me add that the fact that we only have one is the reason why Descartes proposed that the pineal gland is the location of the link between the physical brain and the nonphysical mind. Looie496 (talk) 16:18, 5 July 2011 (UTC)
- Maybe "a" reason, but the location had something to do with it too. 99.24.223.58 (talk) 20:37, 5 July 2011 (UTC)
- Let me add that the fact that we only have one is the reason why Descartes proposed that the pineal gland is the location of the link between the physical brain and the nonphysical mind. Looie496 (talk) 16:18, 5 July 2011 (UTC)
- If you look here and scroll down to the third (slightly blurry) diagram you can see quite easily how the pineal fits in between the two hemispheres. Richard Avery (talk) 22:14, 5 July 2011 (UTC)
- Is it safe to say that anything in the midsagittal plane exists as an unpaired organ? DRosenbach (Talk | Contribs) 01:11, 6 July 2011 (UTC)
- If you look here and scroll down to the third (slightly blurry) diagram you can see quite easily how the pineal fits in between the two hemispheres. Richard Avery (talk) 22:14, 5 July 2011 (UTC)
Hello, i'll say why i thought we have 2.
i understand from a neurobiologist we have X2 of any brain-organ; for example; 2 Thalamuses, 2 Hypothalamuses, and so forth.. by that, plus the written in Wiki, i asked if we have 1 or also two of this.
i understand from the first response indeed we have X2 PG. — Preceding unsigned comment added by 109.67.3.117 (talk) 07:00, 6 July 2011 (UTC)
- I suggest you show your neurobiologist acquaintance these reponses and see what he says. Richard Avery (talk) 07:18, 6 July 2011 (UTC)
- As Richard suggests, you are mistaken and have presumably misunderstood the neurobiologist. There is only one thalamus and one hypothalamus in any one brain: however, both these organs have paired lobes - linked halves lying either side of the midline of the brain - just as the brain itself has one cerebrum divided laterally into two linked cerebral hemispheres without being two cerebrums or two brains in one head. {The poster formerly known as 87.81.230.195} 90.201.110.220 (talk) 10:36, 6 July 2011 (UTC)
Okey, Thanks, i understand what you are saying. but i still must ask what will you say about the following?:
http://en.wikipedia.org/wiki/File:Thalamus.gif
i see here 2 Thalamus's, 1 in every hemisphere. it's clear to me we have to refer it is ONE Thal' spllited into the 2 hemispheres. it's funny though..
thanks anyway. — Preceding unsigned comment added by 79.182.28.217 (talk) 02:36, 7 July 2011 (UTC)
- I see 1 thalamus with 2 lobes joined by a stalk. Great animation. Richard Avery (talk) 06:36, 7 July 2011 (UTC)
Let me try to state the situation a little more clearly. The brain is essentially symmetric, in that every structure on the left of the midline has a matching structure on the right. In most cases the left and right structures are separated by intervening structures (i.e., they form two distinct parts), but there are a few structures where this does not happen, because they impinge on the midline. These include several nuclei in the thalamus, epithalamus (which contains the pineal gland), hypothalamus, and brainstem. Looie496 (talk) 18:25, 7 July 2011 (UTC)
Questions about anti-entropic matter
[edit]Years ago, I read an article in a science journal (it might have been SciAm) about a new study using computer modelling of anti-entropic matter which found, to everyone's surprise, that anti-entropic matter is more robust than originally thought, and that it resists encounters with entropic matter better than expected. It might therefore be possible that there is still anti-entropic matter in the Universe -- that is, matter which is going from a state of less to more order.
Since then, I have been very curious about the properties of anti-entropic matter. For example, what would an anti-entropic star look like? I can't even imagine how it might appear from the perspective of someone looking at it through a telescope. If sufficient anti-entropic matter collapsed to form a hypermass, how would an anti-entropic black hole behave? I've tried asking these questions in a number of places over the years, but no one has ever given me a satisfactory answer. I even tried some of the science websites run by scientists, and haven't gotten a response.
Anyone care to take a crack at answering? -- SmashTheState (talk) 20:56, 5 July 2011 (UTC)
- Sure. Physicists do not recognize any such thing as anti-entropic matter. It is a conceptual error, usually associated with a belief in teleology. Looie496 (talk) 21:13, 5 July 2011 (UTC)
- I can't find the article I read in a dead-tree journal with Google (I searched SciAm and it wasn't in there, so it was another journal), but I do recall reading about computer simulations of anti-entropic matter, and it mentioned that, as you say, physicists had previously believed that it was not possible for any anti-entropic matter to have survived the early stages of the Universe because it would have been rapidly made entropic by interaction with entropic matter. This computer model, however, showed that anti-entropic matter is much more resistant than previously thought, and that it's possible anti-entropic matter could still therefore exist. As I understand it, there is nothing preventing anti-entropic matter from existing, on a theoretical level. The arrow of entropy is entirely arbitrary, and can point in either direction on a quantum scale. My question, therefore, is not a conceptual error. While an anti-entropic star might not exist, the idea is not internally inconsistent. I'm asking for a theoretical answer of how such a thing would appear through a telescope, were it to exist. SmashTheState (talk) 23:12, 5 July 2011 (UTC)
- Let's put it this way: if there is such a thing, it would really be a sight to behold! Suppose I have a Lotto machine (a big tumbler) full of Lotto balls (numbered ping-pong balls) and the machine and balls are made of this stuff. Then it starts out all random and jumbled, but as I turn the crank, they neatly jump up into the tube the balls are released from? Do they end up all neatly in order, from 1 to 40, all facing the same direction with the numbers right side up? Who says that happens? Now, I'm not a great believer in causality, but mixing plus and minus time really confuses me. And that's not even getting into what happens if you dump in half entropic matter and half anti-entropic matter, or if to conserve resources you spray paint normal Lotto balls with anti-entropic matter. (OTOH it might be lucrative research! ;) ) Wnt (talk) 21:42, 5 July 2011 (UTC)
- Come to think of it, if there was anti-entropic matter dispersed in space, as gas or dust particles, I suppose they would all have coalesced into one giant crystal in one place, somewhere. Or perhaps some other work. Actually, as sci-fi, I kind of like the idea - it seems like a plausible explanation for the First Berserker, set aside and ordained from the beginning of time by divine pity, for the moment when mankind must be saved from ascension. Wnt (talk) 21:49, 5 July 2011 (UTC)
- There are serious arguments about this. You can consider a universe that instead of global low intial entopy condition has different sectors in which the time's arrow as defined by the entropy, runs in the opposite directions. Then you can look at what happens at the boundary of such regions. Another recently proposed idea is that the universe started out from an inflating patch but that patch is just a minimum of the entropy, so time runs in both directions from that patch. This means that that we can exist both now and also 27.4 billion years "ago" :) .Count Iblis (talk) 23:23, 5 July 2011 (UTC)
- I can understand having variable, random entropy so that sometimes the "arrow of time" seems to reverse. Tumble a Lotto machine of ordinary balls long enough, and for one shining moment a snapshot could capture 1 to 40 neatly lined up in order. The part that gives me trouble is that some matter would be intrinsically set to increase in entropy and some to decrease at the same time in the same general region of space. Wnt (talk) 23:42, 5 July 2011 (UTC)
Crystals accumulate ordered mass, but they are a solid state phenomenon which does not occur in the other states of matter, and they can not form from other solids, only fluids. Life can also accumulate ordered mass in fluids but not ionized plasma. Crystals and life both depend on external sources of energy to continue to grow. 99.24.223.58 (talk) 03:18, 6 July 2011 (UTC)
- I'd just like to note that no one yet has taken a guess at what an anti-entropic star (or rather, a star made of anti-entropic matter, because the two may be different) would look like. If no one here is qualified to answer, I'd be grateful if someone could suggest a forum where physicists hang out that may be able to provide an answer. (Other than Straight Dope -- I'm banned.) -- SmashTheState (talk) 22:07, 6 July 2011 (UTC)
- Neutron stars might become ordered in a way similar to crystals as they cool, but I can't remember. You should check ArXiv. They are a forum. 99.24.223.58 (talk) 19:39, 8 July 2011 (UTC)
- In particular, [10]. 99.24.223.58 (talk) 19:57, 8 July 2011 (UTC)
mouthwash
[edit]Can I make any good cocktails using mouthwash as an ingredient? — Preceding unsigned comment added by 86.128.100.251 (talk) 21:02, 5 July 2011 (UTC)
- Probably not. This SDMB article goes into the unpleasant details. Tevildo (talk) 22:21, 5 July 2011 (UTC)
- There is a reason for the "Do not swallow" on the bottle. It is toxic.--Shantavira|feed me 05:49, 6 July 2011 (UTC)
- A greenish or bluish version of "white lightnin'". ←Baseball Bugs What's up, Doc? carrots→ 10:32, 6 July 2011 (UTC)
- A scotsman told me that Whisky is an excellent mouthwash as long as you do not spit it out. Cuddlyable3 (talk) 08:45, 7 July 2011 (UTC)
- A greenish or bluish version of "white lightnin'". ←Baseball Bugs What's up, Doc? carrots→ 10:32, 6 July 2011 (UTC)
- There is a reason for the "Do not swallow" on the bottle. It is toxic.--Shantavira|feed me 05:49, 6 July 2011 (UTC)
Roundworms in my cat
[edit](I should start by saying that I am taking my cat to the vet, so I'm not asking for medical advice here.) Just today I observed a roundworm in my cat's vomit. It was like a huge, squirmy spaghetti noodle; quite possibly one of the most horrifying things I've ever seen. So, I've done some research about this, but a lot it is just regurgitated (no pun intended) generic pet-blog info. What I really want to know is what to expect going forward. I wonder if anyone has had an experience with this, and, in the course of dealing with it, come across any good educational resources. Basically, I want to educate myself as much as possible BEFORE visiting my vet, so that I know what kinds of questions to ask her. Also, I'd like to make my cat as comfortable as possible while it goes through the de-worming. Any info/insights would be welcomed. Quinn ❀ BEAUTIFUL DAY 23:17, 5 July 2011 (UTC)
- "The prognosis of a roundworm infection is good if appropriate medication is given promptly. However, in some instances, extremely debilitated kittens may die.... Roundworms can be a health risk to humans."[11] 99.24.223.58 (talk) 00:31, 6 July 2011 (UTC)
- Since people can get them, too, you might want to restrict the cat to one room, with food, water, and a litter box, to limit the chance of them spreading, until cured. Also be sure to wear rubber gloves when changing the litter box, and don't let you cat out, where it could infect other cats and people. StuRat (talk)
- Basically what they will do is give your cat some kind of medicine (I believe roundworms is a "glop of stuff down the throat" sort of thing), and the cat will be fine with it and poop out a bunch of dead worms. In the meantime, keep the cat from spreading it to others by making sure their vomit and poop are isolated and thrown out immediately. It's not likely that you'll contract roundworms yourself unless you are eating things from the garden when the cat does their thing. (You have to eat the eggs. Bleh.) Anyway this is a pretty routine part of cat ownership in my experience. My cat had worms a number of times in its stool, and it was an easy fix each time. It's about the grossest thing I can imagine but as far as cat diseases go, it's very easy to deal with. --Mr.98 (talk) 13:56, 6 July 2011 (UTC)
- The vet will ask you what the worm looked like because there are different pills for round and flat worms. Giving a pill to a cat takes some skill and determination. Cuddlyable3 (talk) 08:42, 7 July 2011 (UTC)