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April 7

Brake Fluid and Clorox

Hi. i was reading an email when it mentioned something about if you mixed Brake Fluid and Clorox it would make smoke.i was wondering if it would make smoke.if not, is there any other household stuff that when mixed will make smoke?(i like pyrotechnic stuff..)

Thanks, --Shannon 00:46, 8 April 2006 (UTC)[reply]

I'm not sure about the brake fluid and bleach, but a Google search will yield some results, such as this. In redox reactions like this, there is an oxidizer and a fuel source to be oxidized. There are too many of these chemicals to list them all, but in the example I gave you above, potassium nitrate is the oxidizer and sugar is the fuel.--Chris 01:12, 7 April 2006 (UTC)[reply]

Thanks.do u know where exactly i can get potassium nitrate from?

There is no way to get it easily from household items. It must be purchased specifically. I recommend ScienceLab.com. Please be sure to review the MSDS for potassium nitrate before deciding to work with KNO₃. I don't suggest that go ahead with this "experiment" if you do not plan to follow proper safety precautions and have some sense of responsibility. Please follow all directions exactly as they are stated and use your good judgement.--Chris 03:28, 7 April 2006 (UTC)[reply]

You might also find it in the local hardware store as 'Stump Remover', where you are supposed to soak the stump in it, let it dry, and then light it. Never worked for me. --Zeizmic 11:56, 7 April 2006 (UTC)[reply]

I thought stump remover is straightup black powder, which does have KNO₃ in it, plus charcoal and sulfur. --Chris 22:41, 7 April 2006 (UTC)[reply]

Hmmm. i will try to find the chemicals and all safety precautions will be observed. Thanks for helpin me find the answer to it =)

--Shannon 00:45, 8 April 2006 (UTC)[reply]

Is sleep deprivation good for anything?

I'm often very tired, and don't have time to get an adequate amount of rest. I'm wondering, is there anything good about sleep deprivation? Flea110 04:22, 7 April 2006 (UTC)[reply]

Well, according to sleep deprivation, it seems that in amongst all the bad things it can do, low sleep levels might help fight depression... temporarily. Seems like the depression usually comes right back after a normal amount of sleep, though. -- Filliam H Muffman 05:10, 7 April 2006 (UTC)[reply]
After 36 hours or so you start hallucinating. GangofOne 07:24, 7 April 2006 (UTC)[reply]
- As this PubMed article suggests, sleep deprivation increases serotonergic activity in the brain, which temporarily relieves psychological disorders such as depression. As a person with social anxiety disorder (which is also linked to low serotonin levels), I can confirm that this is true from experience. You should note, however, that you will only get a noticable effect if you have a chemical imbalance in the first place. Oh, and of course eye candy hallucinations are also encountered with sleep deprivation, although I wouldn't describe them as pleasant. --Aramգուտանգ 08:30, 7 April 2006 (UTC)[reply]
- I agree entirely with aram's comments, and for exactly the same reason. I would add, though, that some artists have used the hallucinations associated with sleep deprivation to good purpose - most famously Salvador Dalí. Grutness...wha? 10:37, 7 April 2006 (UTC)[reply]

I doubt that. I've been up for 36-48 hours straight quite a few times, and never ever had a hallucination. You can get flashes in front of your eyes, but I wouldn't call that a "hallucination". A migraine can give you that too. --BluePlatypus 15:15, 7 April 2006 (UTC)[reply]

Someone here's an outlier then. I've definitely had hallucinations from that sort of length of sleep deprivation (though mine were auditory -- water in pipes seeming like voices, that sort of thing). --Bth 16:02, 7 April 2006 (UTC)[reply]

i heard radiohead frontman thom yorke would use sleep derivation sometimes when writing lyrics modesty 16:20, 7 April 2006 (UTC)[reply]

Sleep deprivation helps me get work done, as I get too tired to be anxious, and my anxiety contributes significantly to procrastination. moink 21:26, 7 April 2006 (UTC)[reply]

Space-Time Curvature under General Relativity

This is a question about how non-scientific explanations of the Theory of General Relativity are supposed to explain gravitation. Layman explanations of space-time curvature usually have a diagram (apparently always the same one) which shows a two-dimensional surface streched (downwards) into a third dimension at the location of a body having mass. The story goes that a second body going by with no acceleration will follow a curved path because space-time is curved by the first body.

What I don't understand is why this would cause one body to curve towards another rather than away. When I try to figure out what the curved path will actually be (from the diagram), it looks like the it should curve away. Apparently, it is implied that the second body would fall into the 'depression' in the original two-dimensional surface because of.... what? the influence of gravity? It's apparently using gravity to explain gravitation. How is this explanation supposed to work? The Wikipedia article hints it's not a simplistic as the picture, but doesn't seem to go beyond that.

If someone is able to post a complete and thorough reply to this question, please forward it to the Nobel Prize committee. Seriously, though, the curved sheet model just takes advantage of the fact that objects rolling around on a big sheet in a 1 G field happen to move in a way similar to what general relativity predicts for objects moving past planets and the like. It's meant to show you how things move, not why things move. To really understand why things move, you will have to understand nasty things like metric tensors and the Einstein field equations. -- Filliam H Muffman 07:24, 7 April 2006 (UTC)[reply]

Well.. I don't quite see why you'd think it would curve away. If you have a downward "dimple" in a tablecloth or similar and roll a ball towards it, moving in a straight line, it will go around the rim in a curved path once it hits the dimple and continue away in a straight line in a different direction, having been deflected somewhat inwards. That analogy is the point of the picture. If the dimple was raised instead of lowered, then it would be deflected in the opposite, outwards, direction. But gravity doesn't act in that direction, which is why you've got a lowered dimple and not a raised one in the picture. --BluePlatypus 07:54, 7 April 2006 (UTC)[reply]

The diagram also gives a nice visual analogy for the inverse square law, since the gradiant of the curve is much steeper near the object than far away. But like the others have said, this is a way of visualizing how the objects would move so, not why. — Asbestos | Talk (RFC) 13:36, 7 April 2006 (UTC)[reply]

In other words, it's just a cool picture? It's describing the exactly the same behaviour as Newtonian gravitation. Peter Grey

Pretty much. It's also meant to give an idea that general relativity deals in spacetime curvature, which, among other things, predicts that light is also affected by gravitation. That makes gravitational lensing possible. Newtonian gravity claimed that light doesn't bend because it's massless. -- Filliam H Muffman 03:03, 10 April 2006 (UTC)[reply]

One of the byproducts of Special Relativity has been the famous equation, E= mc², that first stated the fact of mass and energy being only two sides of the same coin, instead of what previous physicists have conceived. While Newton had previously thought light to be massless and thus insupsceptible to gravitation, nonetheless certain details within the mathematical framework he had produced for gravity as a force did predict a certain amount of bending occuring when light approaches gravitational bodies (a third less than what Einstein later proposed), which, although he knew was true, was never able to explain away with his theory. The new definition in modern physics, now, for the word massless, also meant something different. It refers only to those particles with no rest mass, but not necessarily no remaining kinetic energy whatsoever. Due to Einstein's equation, as previously indicated, you may say that light does have mass if you wish to, since its energy could be easily converted to mass via the constant of c². However, the energy of the photon is constantly changing during its flight, so the records for mass you will be able to obtain will never be invariant, thus referred to as the relativistic masss. In modern physics, however, it is no longer considered appropriate to define the particle on terms of its relativistic mass for obvious reasons, and thus it suffices to say that light is massless in the fact that it has no rest mass. Nonetheless, as long as the photon still possessed the kinetic energy/relativistic mass necessary for its existence, then it shall be supsceptible to curvatures in space- time like other particles with rest mass. Luthinya 10:21, 10 April 2006 (UTC)[reply]

Erm, where have you got that "third less" from? The Newtonian prediction for the deflection of light around a point mass is half the value given by GR. --Bth 10:34, 10 April 2006 (UTC)[reply]

Sorry, got my figures wrong. Thanks for correction. Luthinya 10:45, 10 April 2006 (UTC)[reply]

This kind of picture is indeed confusing, but there is another reason for it that hasn't been addressed fully above. The key is the mechanism by which "curved spacetime" affects the motion of objects (particles, satellites, light, whatever). General relativity says that an object moving only under the influence of gravity follows a geodesic in spacetime, which is the analogue of a straight line in Euclidean geometry. Since the spacetime itself is curved, these "straight lines" have properties we do not expect, but they are, in a precise sense, the "least curved" lines you can have within curved spacetime.

Roughly speaking (see below), one of the important properties they share with Euclidean straight lines is that they are the shortest distance between two points. This means you can picture a geodesic in the following way. Take a curved surface, such as the dimpled fabric surrounding the ball in the relativity diagram asked about above, and fix two points, one to be the "pitcher" and one to be the "catcher." We then want to draw the geodesic on the curved surface connecting the two points, representing the path of an object from the pitcher to the catcher. We do this by using a rubber band, stretched taut: this automatically follows the shortest path between the points.

Now suppose we look at the result as viewed from above. If there were no curvature, the rubber band would be a straight line between the two points. Since the ball is there, dimpling the surface downward, the rubber band will not take a path that appears straight as viewed from above, since that path will be rather long due to the dimpling. Instead, the rubber band will curve around the ball slightly, to avoid the trip into the depths of the dimple. When seen from above, it appears that the ball is affecting the path of the object with some "force", when in fact the object is trying to follow the best approximation to a "straight line" that it can in the circumstances.

All that is rather hard to say without additional pictures, hope it comes across. Anyway, very little of that is usually included with the usual picture, which is why it is easy to come to very inaccurate conclusions about what the picture is trying to say. If you want a better version of all this, look at Taylor and Wheeler, Spacetime Physics.

Note for experts: in spacetime, with its Lorentz metric, geodesics are actually local maximizers of proper time; but part of the point of the kind of picture we're discussing is to give a Riemannian picture. --Spireguy 20:12, 11 April 2006 (UTC)[reply]

Still, for most layemen beginners, it does offer a much more approcheable beginning for the subject, even if much of the important details have been left out. As far as the geodesic problem is concerned, since we as humans possess four dimensions (including Time), and yet space- time may curve in a way that is impossible for us to conceive or imagine- only "talk about", it immediately shows that space- time curves into at least one more dimension than that to which we are accustomed of in our daily life, i.e. the 4D bodies. And just as the 2D figures upon cardboard cannot stand up vertically upon it, since they have no motion or conception of 'depth', we as 4D people cannot cross the barriers of dimension and traverse into the 5th or other higher dimension freely, as we now have the ability to in our 4D world. We therefore have to kind of traverse with the curvatures of the surface of higher- dimensional space- time, which is to us expressed in a 4D fashion like differently laid card boards are to the 2D beings. Thus, for us, the easiest way between two places in space- time may not necessarily be a straight line, but more usually a curved 4D geodesic adapted from the curvatures of space- time from gravity. Luthinya 20:34, 11 April 2006 (UTC)[reply]

That's what I'm getting at. Isn't a path curving away from the point mass shorter? What we would need to visualize would be a contraction of space, not a stretching, right? Peter Grey 04:25, 12 April 2006 (UTC)[reply]

Bear in mind that we're measuring "shortest" in the coordinate system defined by the grid drawn on the sheet. The deformations of the sheet deform the coordinate system itself -- that's the whole point of the analogy. What looks longer to us from outside the sheet is shorter, when measured in a system where the side of a "square" on the sheet is a constant however stretched it looks to us. --Bth 11:12, 12 April 2006 (UTC)[reply]

The shortest path "in the coordinate system" is the straight line. Or is something still missing in the story? Peter Grey 16:13, 12 April 2006 (UTC)[reply]

Um, no. In order to walk the "straight line" in which you are depicting, we must abandon the 4th dimensioned (including Time) curvature of the "surface" of the grid (space- time), and seek to traverse into extra dimensions in order to ignore the curved influences of gravitational objects. However as 4D beings this is pratically impossible for us, so instead of this the shortest route for us will have to be the the curved surface of the grid, which at least is 4D and possible to traverse. Therefore, instead of what Newton has previously proposed, the shortest route between two things is not a 'straight line' in the usual sense of the word, but a geodesic varying according to the shape of surrounding space-time influenced by gravitational fields. At least a longer way is shorter than the impossible, so to speak. The thing is that on the diagram you cannot see the grid curving into extra dimensions the way it should, which is what makes the analogy slightly hard to come to mind. Remember the analogy is only a start to understanding; try eventually to draw away from the picture and just let the ideas flow accross your head- aided by some mathematics, you'll find this much easier.

PS May I add that my above language is extremely inaccurate in depiction, especially without the mathematics to compensate for it. Hope it comes through anyway. Luthinya 18:17, 12 April 2006 (UTC)[reply]

Sports Science

How can the diet of a body builder be compared to the diet of a jockey?

In many ways. You could compare the number of calories, or the proportion of carbohydrates, or even the sheer weight of the two diets. Grutness...wha? 10:35, 7 April 2006 (UTC)[reply]

It's probably a polite fiction that people can significantly bulk up without an Anabolic steroid. Just compare the body builders of yesteryear with the Rambo's of today. --Zeizmic 14:52, 7 April 2006 (UTC)[reply]

It's definitely possible. Depends what your goal for bulk is, but with enough protein and exercise, one can add major muscle mass without resorting to drugs. You may not end up looking like the hulk, but rambo is in reach, given the right genes. Night Gyr 17:35, 7 April 2006 (UTC)[reply]

Time dilation

What is the easiest way to understand length contraction and time dilation?

Here on Wikipedia, a good starting point might be our Introduction to Special Relativity page, which takes a fairly unusual but (IMO) particularly clear geometrical approach. For more details, try our articles on length contraction and time dilation. Elsewhere online, sites like this and this take the more common playing-ping-pong-on-a-train approach. Do come back here if you have anything you want cleared up. --Bth 11:20, 7 April 2006 (UTC)[reply]

Create a super computer by many used computers

I hear that we can create a super computer by many used computer, it means that If I have about 10 pcs of Pentium III Pc, I can create one super computer. The Operating System now is open source.User: Ngocthuan 06 2006-04-7 19:52 UTC

If you had looked at the supercomputer article, you could have probably seen Beowulf (computing), which is the standard model for making a supercomputer cluster. The links and external links in that article will probably tell you most of what you're looking for. — Asbestos | Talk (RFC) 13:19, 7 April 2006 (UTC)[reply]

Logical way to finish this Sudoku?

I got annoyed with the Sudoku today because it took me more than 2-3 stops on the T to solve, so now I've decided that it was a bad puzzle (obviously). I solved the puzzle by supposing one box was one number, working through it all and seeing that it didn't lead to any contradictions. My question is: Was there a logical way to finish this sudoku, without starting with "Suppose this box is a ...", and then showing presence or absence of a contradiction? I realize that that is an ok way of finishing a tough sudoku, but I far prefer it when they can be solved more elegantly:

7 2| 6 | 98 5 |928| 71 98 |74 | 2 ----------- 6 8|29 | 17 273|156|849 19 | 87|2 6 ----------- 3 |872|964 427|639|185 869| 1 |723

Thanks! — Asbestos | Talk (RFC) 13:16, 7 April 2006 (UTC)[reply]

Probably not, the puzzle looks like it's been designed with the "pick one of two choices and see if it leads to a contradiction" method in mind. Parts of it can be solved independently, though: for eample, one of the two possible choices for filling the central square leads to a fairly obvious contradiction in the central columns. —Ilmari Karonen (talk) 17:12, 7 April 2006 (UTC)[reply]

I'd agree, I can't see a way to do it that doesn't rely on guesswork^W proof by contradiction. As such, it doesn't count as a well-formed sudoku to my way of thinking. --Bth 17:18, 7 April 2006 (UTC)[reply]

All solutions depend on proving-by-contradiction. Some of the problems just have more obvious contradictions, making it easier to find the correct one. It's an NP-complete problem, so one solution isn't really much more elgant than the other since they all more or less imply testing all the possibilities. So the perceived elegance is more about whether you can solve it within your mental 'search depth', or whether you have to resort to writing the numbers down. --BluePlatypus 18:23, 7 April 2006 (UTC)[reply]

I see what you mean, but solving using the various other "standard" techniques (listed at length in our sudoku article) doesn't feel like guesswork/proof-by-contradiction in the way that having to employ the "what-if" method does. I've never seen a sudoku before that had to be solved by what-if. (OTOH, I've often solved them by that and then used my knowledge of the solution to see what I'd missed in my application of the other techniques.) --Bth 18:54, 7 April 2006 (UTC)[reply]

Well, yes and no. Personally I feel that a sudoku should be solvable by deduction in that you should logically be able to deduce simply by examining the puzzle what particular number will go into a space. If you are left with a situation where the only way of finding out is to plug in numbers and see whether the correct solution can be reached you've gone beyond deductive reasoning and into inductive reasoning - a different matter entirely, my dear Watson. Grutness...wha? 03:41, 8 April 2006 (UTC)[reply]

Cheating, and using http://sudoku.sourceforge.net/, and adding in all of your available numbers. There is no solution. Sorry! Kilo-Lima|^(talk) 16:54, 10 April 2006 (UTC)[reply]

There is indeed a solution according to that site, although it requires a guess. Are you sure you filled it in correctly? --Pidgeot (t) (c) (e) 20:25, 10 April 2006 (UTC)[reply]

Desktop & Laptop screen placement

1)In a desktop, the monitor is more or less perpendicular to the desk, and we view that monitor with 3 feet distance. If we use a laptop or a tablet pc whose screen is placed at 45 degrees to the desk/lap, should the same distance of 3 feet be maintained? Or simply, if viewing angle changes, should there be a difference in viewing distance?

2)What is the reccommended viewing distance and reccommended angle for placing laptop screens?

When we place the screen on the laps in a slate tablet PC, the viewing distance is 1 to 1.5 feet. Does that say that viewing distance is related to angle of viewing?

Laptops and tablets are not particularly ergonomic. Get an external keyboard and jack your laptop up on some phone directories when you are using it as a desktop replacement. For great justice. 18:38, 7 April 2006 (UTC)[reply]

You can get stands that hold the laptop screen vertically at eye level (the ones we use do so by having a 30° tray to put the laptop base-part on, with the hinge furthest away from you) and plug in an external keyboard and mouse. Ojw 20:36, 8 April 2006 (UTC)[reply]

Your screen is probably not at a 45 degree angle; many laptops are barely even capable of bending that far. Night Gyr 06:29, 9 April 2006 (UTC)[reply]

Can Envelopes Be Composted?

Paper can be recycled or composted but envelopes cannot be recycled due to the glue. Can envelopes (without plastic windows) be composted? --Username132 (talk) 15:16, 7 April 2006 (UTC)[reply]

Theoretically, most things can be, but consult your local recycling company for their facilities / policies on this. For great justice. 18:36, 7 April 2006 (UTC)[reply]

I'm sorry - you said composted, not recycled! They will certainly break down if you put them in a composter - the question is, not knowing exactly what chemicals are in it, you might not want to use the compost on vegetables etc you want to eat - otherwise, go for it. For great justice. 22:24, 7 April 2006 (UTC)[reply]

The recommended constituents of compost are: 1) vegetable waste (and some miscellaneous kitchen waste like tea bags, eggshells, etc), 2) lawn trimmings or leaves, and 3) shredded newspaper, straw, or wood chips. Bleached paper (normal office paper, including envelopes), cardboard, other paper, cooked food, animal-based waste (except eggshells), fats, etc while capable of decomposition, are NOT recommended for composting.

In the case of office paper (as per your question), it is both the chemicals in the paper and the density of the paper. 'Perfect' compost is alternating layers of dense vegetable matter (kitchen scraps), dry vegetable matter (lawn trimmings or leaves), and cellulose (straw, wood chips or SHREDDED newspaper), not necessarily in that order but definitely including all three. The combination of the three types of elements is ideal for the cultivation of all the different types of organisms that turn waste into soil. If you don't follow the 'formula', your compost will still decompose, but it will be slower, smellier, and grosser.

Newspaper is included for two reasons; one is that it aerates the pile, and it is actually nutritious to worms. White paper is like refined sugar, it has no nutrient value, so worms wouldn't eat it. It's also dense and soaked with chemicals, which would inhibit the movement of the worms and maybe poison them. IF the paper decomposed, it would be a slow process facilitated by bacteria which would be acting on the organic drippings from other parts of the compost that would 'soak in' to the paper. It's waaaaay better to leave it out, most compost experts say leave it out. Recycle your office paper through your city's recycling programme, or send it to the dump to follow its own decompositional path, away from your compost pile.--Anchoress 00:55, 11 April 2006 (UTC)[reply]

Thank you - compost without the envelopes it is! :) --Username132 (talk) 04:06, 11 April 2006 (UTC)[reply]

No problem. I also forgot to mention that - as far as animal waste is concerned - manure is fine, but not dog, cat or human feces. Also some documentation says cardboard is OK, I think the main thing is unbleached, unpressed paper, and ideally it should be shredded. In my jurisdiction they say only newspaper, no other kinds of paper.--Anchoress 04:34, 11 April 2006 (UTC)[reply]

Dr. Keith Black neurosurgeon

Why is there no information on Kieth Black M.D. on wikipedia ?

Because no one has added anything about him yet. I didn't know who you were talking about so I looked him up. He doesn't seem terribly notable to me, but if you feel like adding information about him, go ahead. Be Bold. Chapuisat 16:55, 7 April 2006 (UTC)[reply]

He seems sufficiently notable to me to warrant an article (and to displace the drag-racing Keith Black to a disambig link), so I've created a stub for him based on a quick Google search; I'd strongly encourage the questioner to add some info if they have any. More generally, to expand on Chapuisat's point, Wikipedia has gaps and omissions because it's entirely the result of volunteer contributions and constitutes a permanent work in progress. --Bth 17:00, 7 April 2006 (UTC)[reply]

If one added every living and dead physician, lawyer, and dentist, then we would have maybe over 10,000,000 articles on these folks alone. Unless that person made a breakthrough and accomplished something meaningful, I don't think such articles would be needed.Patchouli 23:54, 7 April 2006 (UTC)[reply]

Linux

From a Linux tutorial; "Most modern Linux distributions encourage a practice in which each user has a specific directory for the programs he/she personally uses. This directory is called bin and is a subdirectory of your home directory."

Would it not be inefficient for many users to have different copies of the same program? --Username132 (talk) 16:42, 7 April 2006 (UTC)[reply]

Well, if it's a big multi-user system, each user probably has a disk quota that they can use to store whatever they want. If the programs they want to run aren't available in /usr/bin or /usr/local/bin or whatever, they can put them in /home/whoever/bin. —Keenan Pepper 17:07, 7 April 2006 (UTC)[reply]

And the particular situation of everyone having a local copy of SuperWhizzyUtilityX shouldn't arise if the sysadmin's on the ball. They should be putting anything that several users want into /usr/bin and such places. (Incidentally, if you want to see where the shell searches for executables when interpreting command lines, type "echo $PATH" to see the (colon-separated) list stored in the PATH environment variable.) --Bth 17:15, 7 April 2006 (UTC)[reply]

It may be a tad inefficient, but it's a lot better than sharing the same installation - what if someone deletes the program? Bth's point is also a good one - commonly used applications get installed into a shared directory they can access but not modify.

Gold in sea water

I have read somewhere that there is approximately 9 tonnes of gold per km cubed in sea water. --

-Is this true for all seas (apart from where there is large amounts of fresh meltwater)?

-Is the same true for fresh water and what is the amounts?

-Is the gold not worth anything (like industrial diamonds)?

-Is there an efficient/cost effective way of extracting this gold, taking into account; positioning (what sea/ocean), labour, building/machienry etc.

-If you discover anything "good" please don't make it "exceptionately clear" to anyone else and put it on the website. I cant force you to but pretty please do.

Im slightly mad but if it wil work i will be slightly rich....Yipee!!!

                I think im ment to do this: --William Dady 16:58, 7 April 2006 (UTC)[reply]

The presence of trace amounts of gold and other precious metals in seawater is not a secret, and it is not economically feasible to extract it because the concentration is so low. 9 tonnes may seem like a lot, but a cubic kilometer is a ridiculous amount of water. See [1] and Fritz Haber, a brilliant chemist who tried and failed. —Keenan Pepper 17:12, 7 April 2006 (UTC)[reply]

To put it into perspective, a cubic km of water weighs about a trillion (1,000,000,000,000) kg, or a billion metric tonnes. So you got a concentration in the 9 parts per billion (mass) (by your numbers).

The 1st billion tonnes is the hardest. --GraemeL ^(talk) 23:39, 7 April 2006 (UTC)[reply]

Thanks for your query. We figured it out but sorry we're not sharing. alteripse 14:59, 8 April 2006 (UTC)[reply]

Finally, there are two metals that might one day be economically viable to extract from seawater - uranium and vanadium. See this abstract. Arthur C. Clarke wrote a short story about the idea decades ago. --Robert Merkel 08:12, 9 April 2006 (UTC)[reply]

Centrifugal Force

If a space station were to have a ring with people inside and it was spinning fast enough then it should create artificial gravity. So my question is if a person inside this ring where to jum up would he or she be pulled down to the spot where the jumped up from? Patrick Kreidt

Essentially, yes. You should draw a force diagram of the situation you are talking about. I think you are interested in whether the ring would 'spin' under the person while they were in the air? Sketching out a diagram will show that there are no forces that will do this in the example you mention. For great justice. 18:34, 7 April 2006 (UTC)[reply]

I don't think so. Maybe I have not thought this completely out, but here is how I see it. At the time a person jumps 'up' (and 'up' is defined as perpendicular to the surface) a person will be moving forward at a certain speed. Ignoring air friction the person will continue to move forward at the same speed the floor is moveing forward. Since the floor moves in a circle and the person does not, for the person to come down in the same place would require the floor to travel a longer distance in the same time the person requires to land. From this I conclude the person will land in a spot a little ahead of the take-off point.

Why doesn't the person move in a circle? As the ring spins, it emparts momentum to the person at an angle tengental to circle, that means they spin, with the ring, and are pushed away from the center of rotation. If the person jumps towards the center of the ring, they already have momentum emparted by the ring that will carry them 'forward' at the same rate that the ring is spinning. For great justice. 20:49, 7 April 2006 (UTC)[reply]

File:Ringgravity.jpg

OK - so take a look at the diagradm - the black arrow shows the force vector of the spinning ring. The red arrow the direction of spin, and the green arrow the arc of the jumping man. Because he has the same forward motion as the ring, the arc he describes, even if he jumps 'up', will put him back where he began. For great justice. 21:06, 7 April 2006 (UTC)[reply]

That's roughly true, but remember that the ring moves in a circle, whereas the person's initial velocity (aside from the "jumping speed") is tangential to the circle at the time of the jump. I think you land in roughly the same place, for small jumps, but getting an exact answer requires actually calculating it out. -- SCZenz 21:21, 7 April 2006 (UTC)[reply]

Er, I don't think it quite works like that. You have to remember that there's no force 'down' (outward) on the jumping man, just whatever residual momentum he carried when he left the ring.

Picture the following situation. The ring sits in the plane of this webpage, like this: → O

The ring rotates counterclockwise. The top of the ring is moving left (←) and the bottom is moving right (→).

Our hypothetical spaceman is standing on the inner surface of the rotating ring. Assume that we conduct our experiment just as he reaches the bottom of the circle. He, and the ring, are both going to be moving to the right (→) with equal speed.

The spaceman jumps. He retains the original horizontal component of his speed → and adds a modest upward component (↑), assuming he pushes off normal to the ring surface. The path he follows will then be straight along the vector sum of those two components, taking him diagonally up and to the right on our diagram until he smacks into the wall again (er, lands).

So, what happens? Let's follow the spot of ring from which our spaceman started. Its horizontal velocity will be

v_horiz(t) = v_max·cos(ω·t)

where positive velocity is to the right. In other words, its velocity is at a maximum at the bottom of the circle, and decreases as the centrifuge turns.

Our spaceman, on the other hand, retains all of his initial horizontal velocity, so he lands ahead of his starting point. TenOfAllTrades(talk) 21:21, 7 April 2006 (UTC)[reply]

Hmmm...looking at that explanation, I think I can cut it down a bit by looking at the problem in a slightly different way.

File:Ringgrav2.jpg

The launch point on the ring travels at constant speed along a curved path.
The astronaut travels at a constant speed greater than the speed of the ring surface (remember the vector addition of his jump velocity to the ring's velocity) along a straight path.
The two paths intersect at some point after the jump.
The astronaut gets there first — he followed a straight path at higher speed. Therefore, the astronaut will land at a point on the ring ahead of his departure point. TenOfAllTrades(talk) 21:26, 7 April 2006 (UTC)[reply]

So, my diagram is wrong, because the spaceman describes a straight line, not a parabola? For great justice. 21:30, 7 April 2006 (UTC)[reply]

Huh. Thanks, that'll teach people to trust anything that they read on the internet! So, why does this not work on earth, which looks like the opposite case? For great justice. 21:27, 7 April 2006 (UTC)[reply]

I think it does work on earth, but the difference is so small it can be ignored. Keep in mind, on Earth you will only be jumping maybe 3 feet, on a ball with a 4000 mile radius. I will try to explain, though. Remember that circumferance increases in direct proportion to the radius. This means the arc of a circle with 4000mi radius will be slighty shorter than the same number of degrees of arc of a circle with 4000mi+3feet radius. This means your jumper will have to move a longer distance in the same time the earth does to traverse the same arc.

How about this version? For earth, actually I think the difference is that you do describe an arc, not a line, because gravity is continually acting on you - no? For great justice. 21:34, 7 April 2006 (UTC)[reply]

The Earth case is quite a bit more complicated due to gravity, yes. Where you land (ahead or behind your starting point) depends on the size of the centrifuge and speed of rotation (note that it has to be fast enough that you don't fall off when you go over the top....) as well as the impulse you give yourself during your jump. In the special case where you jump while the centrifuge is at the bottom center (as described in my first though experiment above), you'll land ahead of your jumping off point—it comes down to the person maintaining a constant horizontal velocity while the jumping off point is losing the horizontal component of its velocity. I'm too tired to work through the consequences for anywhere else on the centrifuge right now. TenOfAllTrades(talk) 03:41, 8 April 2006 (UTC)[reply]

The easiest way to figure out the direction of these effects, and their approximate magnitude, is to pretend the Earth (or other spinning body) is actually at rest, but apply the Coriolis force. --Trovatore 16:40, 8 April 2006 (UTC)[reply]

1) There is no such thing as actually at rest.

2) The very fact that you may apply the Coriolis force to a body already implies that it's spinning.

The field of 'artifical gravitation' generated by the spinning ring must be understood as a fairly universal field of 'gravitation', at least certainly one in which the Equivalence Principle may apply, in making this question at all possible. Yet when the astronaut jumps vertically from the ring's frame of reference, the artifical gravitational field acting upon him draws slightly weaker effects due to the longer distance, but the field itself still remains fairly universal for our purposes. However, when the astronaut is jumping up, though he shall still ultimately be drawn to the ring, during his time of suspension he is no longer travelling in the direction of its spin or with its velocity. As we have settled that the field shall be considered universal for our purposes, then it follows that he shall not be drawn to the particular place from which he jumped more than any other. Thus, following the above discussion, it appears plausible that the astronaut shall land in a slightly different place from where he jumped, the exact position determined by other factors and certainly noticeable if the ring was spinning fast enough- and he had not jumped too far away!

Galileo himself actually suffered the same kind of inaccuracy due to the spinning of the Earth from his famous experiment on the Tower of Pisa, however in that case the indescrepancy was too small to mar the ultimate judgment of the experiment. Luthinya 10:38, 9 April 2006 (UTC)[reply]

Chemical structure formula in Word?

Does anyone know of any (free) application able to draw chemical structure formulas and save them into the WMF or EMF format, so that they can be inserted in for instance Microsoft Word? --Andreas Rejbrand 18:39, 7 April 2006 (UTC)[reply]

You might try ChemSketch.[2] There's a free version, but I'm not sure what file formats it can save in. ChemDraw can save in those file formats, but there aren't any free versions, as far as I know. --Ed (Edgar181) 18:47, 7 April 2006 (UTC)[reply]

Thanks; I'll have a look at it. --Andreas Rejbrand 18:49, 7 April 2006 (UTC)[reply]

Now I've tested it, and it really looks great. Thank you for informing me, Edgar181. --Andreas Rejbrand 19:12, 7 April 2006 (UTC)[reply]

Total human decomposition in Canada

A tall order, I know, but I was wondering how long it would take a human body to totally decompose in a four-season (with a "real" winter, which is to say at least one or two months below zero degrees Celsius) environment.

I've read up on decomposition and eco-cemeteries (the latter being the reason I'm interested in the question), but neither go into enough detail to really tell me how long, pillar to post, it takes before a body is entirely gone. Skeleton included.

I'm aware that there are factors like ground moisture, limestone, etc. involved, but a ballpark-by-decade would be great. 10 years? 20? 60? Thanks! --MattShepherd 20:13, 7 April 2006 (UTC)[reply]

I'm no expert but i know the location where you bury the body really matters, they've found human skeletons and even bodies still fully formed (in admitedly extreme conditions) that are hundreds of thousand of years old.

The tricky part is the skeleton, which generally requires salt-water or something rather caustic to break it down. The rest is broken down fairly easily, unless there is some extreme condition in which microbes can not exist. StuRat 07:57, 8 April 2006 (UTC)[reply]

Skeletons can remain for ages in good conditions. Your best bet would be to contact the Body Farm in Tenessee, but you'd better explain why you want to know to them... - Mgm|^(talk) 19:40, 8 April 2006 (UTC)[reply]

what if..

if every single human being on the face of the earth decided to jump 1 foot to the right, at the exact same time would it be enough force in one direction to shift the earths orbit? tilt? tidal forces? register on a ricter scale?21:13, 7 April 2006 (UTC)

The Straight Dope answers the question for the specific case of China - seems like not much would happen. [3]. Answerbag has another demonstration of why this is bogus [4]. For great justice. 21:17, 7 April 2006 (UTC)[reply]

nah thers no way, but i mean if you do think about it, every particle in your body is exerting gravity on everything... all the time modesty 03:58, 8 April 2006 (UTC)[reply]

I think this is an example of the falacy of equivalence of large numbers. The earth is really big, and the number of people on it times their weight is really big. Therefore they are equivalent, and one will automatically effect the other. For great justice. 22:19, 8 April 2006 (UTC)[reply]

Why does DNA only replicate in the 5' - 3' direction and not vice versa?

I know this is kind of a homework question and you guys don't like that which is fair enough, but i'm revising for my degree and really have no idea why. I am generally quite interested anyway. Cheers, Mark west 80.42.104.21 22:23, 7 April 2006 (UTC)[reply]

I believe it is because the enzyme that catalyses the the replication process can only grip on the "5" end of a strain. Since it can't start at the "3" end, 3-5 replication does not happen. Note that this is from my sketchy memory of biochemistry 5 years ago. SanderJK 23:27, 7 April 2006 (UTC)[reply]

WRT homework questions, there's no problem with asking specific factual questions (like yours seems to be, though it's an area I know nothing about). What we object to is when people post an essay topic, or a physics homework problem, or the like, and expect us to do the task for them in its entirety. --Robert Merkel 00:28, 8 April 2006 (UTC)[reply]

The reason that synthesis can only occur in the 5'-3' direction is based on the reason these names exist in the first place. If you are an applicant for a degree in molecular biology or something similar, then you know that these names, 5' and 3', refer to the carbon positions in the deoxyribose backbone. Both the 3' and 5' carbons have hydroxyl (alcohol) groups attached, however, wheras the 3' carbon is part of the ring, the 5' carbon is sticking out (read: much more reactive). Therefore, when DNA is split into monomers, deoxyribose molecules with purine or pyrmidine residues, the 5' carbon loses a bond, whereas the 3' carbon is not directly affected (instead the oxygen in the hydroxl loses a bond). Now consider this, since the residue separating the 5' end of one monomer and the 3' end of the next is a phosphate, the electron in the bond between a phosphate (which is completely resonance stabilized) and the sugar monomer is much more likely to go to the phosphate. Thus the positive charge can stick on the 3' oxygen (unlikely) or the 5' carbon (very likely). So wiht all this information, we can explode a diagram of DNA: you have a sugar monomer with a + charge at the exposed 5' carbon and a stable 3' carbon with full bonds and a stable hydroxl; and a phosphate with a - charge. Thus the most likely eventuality is a deoxyribose monomer with a phosphate attached at the 5' carbon. Since the active sight on the polymerase protein is reactive to the hydroxl side, it sits on the 3' end of the DNA chain and waits fot another monomer to come by, then attaches it via the floater's 5' end. Look at this attachment form far a way, and the chain appears to be growing from the 5' to the 3' direction.Tuckerekcut 16:23, 9 April 2006 (UTC)[reply]

Awesome answer, that helped a lot, thanks Tuckerekcut.

What is the alloy grade of cast steel which used for cylinder head?

In low speed diesel engine, the cylinder head is Manufactured from cast steel. Please, I need to know the alloy grade of cast steel and the folloing properties: 1- denisty 2- specific heat 3- thermal conductivity

thank you

That's a toughie. You might have to ask a manufacturer of low-speed diesels like MTU to find out - or get a hold of a sample and take it off to the metallurgy lab. If you're interested because you want to set up in competion to them, the latter might be your only option. --Robert Merkel 00:35, 8 April 2006 (UTC)[reply]

April 8

Electrical Storms

Why do electrical storms only seem to occur in a rainstorm, but never in a snowstorm? Loomis51 00:19, 8 April 2006 (UTC)[reply]

It's possible to see lightning in a snowstorm. I saw it several times in New Hampshire. Brian G. Crawford 01:10, 8 April 2006 (UTC)[reply]

See the environmental lapse rate page. A thunderstorm derives some of its energy from air rising in an unstable atmosphere, and moisture condensing as it cools. Warmer air on the bottom can hold more moisture and is more unstable than cooler air. EricR 01:55, 8 April 2006 (UTC)[reply]

Also, does lightning strike in the sea, and if so does anything special happen compared to striking land? --Username132 (talk) 01:28, 8 April 2006 (UTC)[reply]

Lightning in a snowstorm is referred to as thundersnow, and we had it here this winter. Night Gyr 03:27, 8 April 2006 (UTC)[reply]

It depends a lot on other factors, probably - such as the location of the storm, wind currents, etc etc etc. Here in southern New Zealand, for instance, thunderstorms are almost always accompanied by hail rather than rain. And yes, lightning quite often strikes over the sea (where I live I've got a great view over the Pacific), with no obviously spectacular results. Grutness...wha? 04:37, 8 April 2006 (UTC)[reply]

Oxidizing Heavy Metals Salts

I would like to know in details about the oxidizing heavy-metal salts as this relates to corrosion of copper and copper alloys. Copper alloys resist many saline solutions, alkaline solutions, and organic chemicals. However, copper is susceptible to more rapid attack in oxidizing acids, oxidizing heavy-metal salts, sulfur, ammonia (NH3), and some sulfur and NH3 compounds.

We have a corrosion problem in one of our gas engines of Caterpillar and the service engineer identified the occurance of oxidizing heavy-metal salts on a engine part made of copper alloy.

I would appreciate your helping me out of this situation by providing details obout oxidizing heavy-metal salts.

Thanks & Regards,

Ahmed Mohiuddin Caltex Oil (Pakistan) Limited A chevron Company

The obvious answer is to replace the copper with something less reactive, like gold or platinum. Another option would be to supply a "sacrificial rod", say made out of aluminum or magnesium, which would react with the heavy metal salts in place of the copper. The rod would need to be replaced as it corrodes, of course. One option might be to place the rod in the oil reservoir. Hopefully, the oil will carry the salts to the rod before they can attack the copper. The rod could be attached to the oil cap, but must be long enough to extend down into the oil in all conditions. Water heaters often use a sacrificial rod. StuRat 07:28, 8 April 2006 (UTC)[reply]

You may be looking for the article on sacrificial anode. TenOfAllTrades(talk) 14:28, 8 April 2006 (UTC)[reply]

Adobe Photoshop Album Starter Edition 3.0

okay....im really starting to get mad at my Adobe Photoshop Album Starter Edition 3.0 because every time i go to a website any pictures that are on the site are automatically saved to it. Does anyone know how to stop it from doing this?I dont even have to look at the picture specifically...it just automatically saves it....really annoying.

Thanks for any help, Shannon 03:15, 8 April 2006 (UTC)[reply]

This is NOT a science question. Ohanian 04:46, 8 April 2006 (UTC)[reply]

No, but it's a computer question. I don't know the software, but look for a preferences tab on programs icon bar, failing that, what do you use it for? Why not uninstal it and use a free image editor like The Gimp? For great justice. 06:49, 8 April 2006 (UTC)[reply]

Ohanian, please note this text from the main ref desk page, referring to the Science desk: "To ask questions about science, medicine, computing, and technology" --LarryMac 20:17, 10 April 2006 (UTC)[reply]

okay ill do that thanks. Shannon 01:14, 9 April 2006 (UTC)[reply]

What is hafnium's cosmic history?

What is hafnium's cosmic history? I've looked everywhere I think I could find that information, but I can't seem to get any information that I need. Could you help me find the information I need, please?

What do you mean by "cosmic history"? The only thing I can think of is how it was originally formed, which it shares in common with all the heavier elements, so I don't understand why hafnium has been singled out. You may want to look at our article on nucleosynthesis for more on that. --Bth 07:12, 8 April 2006 (UTC)[reply]

Ear ringing

My ears ring when I have earplugs in, I read in the wikipedia article that theres no cure for it, but I was wondering if this was normal, and if there was anything I could do to make them stop ringing, thanks.

Flents

I have used Flents foam ear plugs which I have learned reduce ringing more than any other type of earplug. However, after wearing earplugs for over six hours every day for some time, I noticed that the ringing sound stayed even after I took the earplugs out of my ears; this is tinnitus. I my case, it ceased after I stopped putting earplugs in my ears for a month. Try to use the earplugs only if it is necessary.Patchouli 09:44, 8 April 2006 (UTC)[reply]

The ringing you are experiencing is indeed called [tinnitus], but it is not caused by the earplugs themselves. Most likely your tinnitus is constant throughout the day, however you dont notice it because of the ubiquitous background noise of daily life. Even in the dead of night, the hum of environmental control systems and various electronics in your environment distracts your attention from the ringing sound. However, when you put in earplugs, these sounds are muffled, and the ringing sound, which has been present as a tiny, unwavering signal from your ears to your brain, becomes relatively large compared to the background noise, and you notice it. Unfortunately, tinnitus tends to get worse as we age, mostly from incremental damage to our sensitive ears. Ringing due to acute damage may fade away after a few hours or days, but the underlying chronic tinnitus described here tends to be permanent. Tuckerekcut 15:54, 9 April 2006 (UTC)[reply]

Not enough sleep...

having "black lower eyelids" (i don't know its real name) has always been frustrating to many people. i always wonder why they appear when we don't get enough sleep, and perhaps there might be some other reasons?... i would be more than grateful if you could just stop by and answer this question for me. Thx! --219.77.165.58 11:18, 8 April 2006 (UTC)[reply]

The skin around the eye (especially directly under it) is extremely thin and has a lot of blood vessels in it. While you are awake, your eyes stay open most of the time and you get a buildup of gunk (wax, dust, salt, etc...) in your eye. Tears help keep it clean, but they work best at night with your eyes closed and with plenty of REM. That buildup does two things - pushes blood vessels closer to the surface of the skin and blocks flow, making the vessels expand slightly. The more visible vessels are what you are seeing when you see shadows (and puffiness) under you eyes. --Kainaw ^(talk) 16:49, 8 April 2006 (UTC)[reply]

By the way, the more common term for this is "bags under the eyes". — Asbestos | Talk (RFC) 14:28, 10 April 2006 (UTC)[reply]

genius v.s. lunatics

many great mathematitians and well known scientist have the tendency of being nuts, but why is that? Thx :)

A simple answer to your question is that people who are capable of making brilliant new developments (in any field whether it's math, science, philosophy, etc.) tend to be people that think differently than others, that look at problems in a new way, or don't simply accept the traditional point of view. Society tends to think of people with that kind of outlook as nuts (or at least "eccentric" in polite company). --Ed (Edgar181) 11:42, 8 April 2006 (UTC)[reply]

I'm also fairly sure that the genius/lunatic thing is incorrect. In my recollection, there is no correlation between true mental illness and intelligence, but the cases in which they do correlate are generally so interesting and noteworthy that we end up letting them dominate our perception of it. --Fastfission 12:07, 8 April 2006 (UTC)[reply]

I'd agree with both statements, and would like to add the fact that from my runins with various scientists i would say that many fields tend to attract certain kind of people, and that the studying of some fields can really change your view of the world. Combined with a certain social ineptness that does seem more common among researchers then in most circles, and the relatively often portrail of autistic savant in popular media, and the fact that abnormal people (including scientists) will get more media attention in general, it is easy to understand how such a picture of scientists would become widespread. Most of all, they are just people, perhaps with a little workaholic nature engrained. SanderJK 13:00, 8 April 2006 (UTC)[reply]

My cynical hemisphere will bet it's 99% a matter of noticing. Ordinary person has mental illness-- no news. "Brilliant" mathematician (is there any other kind?) or scientist has mental illness, and everybody can feel reassured that they are better off and savor the irony of the smarter guy's misfortune. Eccentricity and poor social skills are usually distinguishable from major mental illness. (what is the dsm-iv for "nuts," anyway?) alteripse 14:56, 8 April 2006 (UTC)[reply]

In the case of a "genius", poor social skills and a constant preoccupation are what others call "mental illness". As an example, Einstein has terrible people skills. After his wife died, he became a shut-in. When in public, he either did his obligatory presentation or stayed away from the crowd, preoccupied with other things. Over and over, the genius form of antisocial behaviour has been explained as a disdain for the stupidity of humans in general. Einstein's quote, if I remember correctly, is that "Only two things are infinite, space and human stupidity. I'm not sure about the former." As for the preoccupation, they are working on problems that they find much more interesting than what to have for dinner or which politician do we want to raise our taxes next year. All in all, I see it as an adult trying to fit in with a class of preschool children. The children aren't really stupid, they are normal. The adult isn't mentally ill either. They are just focused on different things. --Kainaw ^(talk) 16:44, 8 April 2006 (UTC)[reply]

OTOH, a large part of Einsteins 'genius' status is the fact that he fit so well into the stereotype. I'd say he was a large part of defining it. By comparison, Bertrand Russell for instance, shared a similarily negative view of humanity but was quite social. Given the political activism of both, it's quite obvious that they weren't actually disinterested in humanity itself. All in all, I think the 'insane genius' myth says more about people in general than about the geniuses. First, it displays our need for 'heroes', placing some people on pedestals way above everyone else, even though they're actually just at one end of a continuum. (Einstein was a genius, but was Niels Bohr? Feynman? Gell-Mann? Weinberg? Aage Bohr? Any Nobel-prize winner? Etc) Second, it illustrates a human tendency for 'justice'. People who are very smart must somehow 'pay' for that by having diminished ability in other areas. So geniuses are anti-social. Athletes are stupid. Etc. Sure, there are lots of 'geniuses' who were single-minded and anti-social, but there are those people on any job that doesn't require those skills. And as Alteripse said, there's a big difference between eccentric behaviour and real mental illness. Another factor might be cranks - people might reason along the lines of a crackpot simply being a genius who's wrong or misunderstood. (that's certainly how they see themselves!) A lot of them do seem to have some form of personality disorder, and they also seem to have a rather homogenous set of personality traits. (dogmatism, delusions of grandeur) But those personality traits aren't the ones that make a good scientist in the real-world. --BluePlatypus 20:40, 8 April 2006 (UTC)[reply]

As a friend of mine likes to say: "The line between genius and insanity is very thin. In Mexico, we call it the Rio Grande." Grutness...wha? 01:25, 9 April 2006 (UTC)[reply]

Someone asked me once whether I suffered from being crazy. I replied that I don't suffer, I love every minute of it. Of course, that was a quote from someone so I can't say I actually made it up, but it demonstrates a distinct lack of feeling by most people towards those who are different. I would never think I suffer from being like I am (ie. a crazy scientist :-) ), but others would instantly think that because they could never like my situation that I mustn't like it myself. Ans e ll 01:25, 9 April 2006 (UTC)[reply]

I think your comment demonstrates a certain lack of feeling towards those who have a genuine mental disorder. Many of them do suffer, profoundly. --BluePlatypus 03:50, 9 April 2006 (UTC)[reply]

:-D I was speaking with tongue in cheek of course. Ans e ll 03:59, 9 April 2006 (UTC)[reply]

Boy, I just don't know where to start with this one. What exactly do you mean by "lunacy" or madness, anyway? I think we have to be careful to distinguish between mere eccentricity and clinical psychopathology. Just because a highly intelligent, academically oriented person has no social skills and little sense of fashion does not mean they are "nuts," although the tabloids would have us believe that was the case. And not all types of madness have been deemed favorable to achievment. The "mad genius" stereotype has been around for a long time, especailly as applied to artists. The art majors on college campuses know that they can get away with all sorts of odd behavior and have it explained away as a manifestation of "artistic genius." Similarly, slovenly, asocial maths geniuses are often excused for their faux pas because such things are somehow a mark of their superiority in the intellectual heirarchy. People like Kay Redfield Jamison have written books about the correlation between bi-polar disorder and certain types of "creative genius." And the media has been playing the "Asperger / Engineer" connection for about 10 years now. Correlation is not cause, however, and it may be that the reason some of these famous "mad" geniuses have been so productive is that, in addition to having psychiatric disorders, they were highly intelligent and highly motivated. This may have enabled them to not simply "work around" their problems but to incorporate some of their supposed problems into a successful combination of skills. For example, many math and music prodigies experience synaesthesia, which gives them a unique perspective and provides an alternate path to understanding their fields. Manic episodes allow some people to work compulsively for days on end until a particular problem or project reaches a satisfactory conclusion. I seem to recall some evidence that in the bi-polar brain, some of the excess neurochemicals that build up in one portion of the brain "spill over" into adjacent areas associated with creative and other activities. And depressives have been found to have an enhance ability to recognize the true consequences of personal and political actions. I'd better stop now. This topic seems to be making me feel a bit crazy. Ande B 09:02, 9 April 2006 (UTC)[reply]

The whole problem may be solved on a point of perception. Unless you believe in absolute normality, there really is no single frame of reference from which one may judge sanity. From the scientist's point of view, it may the casual person who is mad. This lunatic behaviour was only caught on the exaggeration of the media and the apparent inpenetrability of many famous scientists/mathematicians. In many cases, misunderstanding and misinformation has always tend to crowd scientists with an air of mystery which others, in failing to understand, classifies as 'eccentricity'. The problem is that scientists are not always interested in making the general public understand themselves, and thus solve the mystery.

Then one must stress that the scientist does not necessarily have a mental illness such as schizophrenia, but his novel ways of perceiving the world, and often autistic moods, sometimes decieves the passer- by into thinking that this is so. In many cases their ways of percieving the world may even be stereotypical enough to be one step from the ideas of a lunatic, save that it is also usually supported by reasoning. The truth is scientists are not always willing to conform themselves in order to undecieve others, and our society does not always enjoy the company of those that do not follow its rules. Luthinya 10:06, 9 April 2006 (UTC)[reply]

This discussion is too lengthy to be worth reading. The title thereof implies that every Nobel Prize winner, Fields Medalist, Wolf Prize inner, Shaw Prize winner, Abel Prize winners, etc. + inventor, computer designer, corporate leaders or anyone who didn't watch soap operas, sitcoms, party, and goof off is moron.Patchouli 02:03, 10 April 2006 (UTC)[reply]

Unfortunately, this is pretty much how most of our society tends to view especially technological geniuses. Don't get me wrong- I'm often avoided as a nerd for reading maths/physics books all the way through lunchtimes in my high school. Luthinya 10:29, 10 April 2006 (UTC)[reply]

dynamic programming

how to implement dynamic programming using 'c' language — Preceding unsigned comment added by 59.92.34.98 (talk • contribs)

Our article on dynamic programming is quite general; the ideas should be readily applicable to C. --Bth 14:27, 8 April 2006 (UTC)[reply]

C# Adding Machine

Please can someone give me the code required to make an adding machine in Microsoft Visual Studio C sharp 2005 express edition? Computerjoe 's talk 12:53, 8 April 2006 (UTC)[reply]

sounds like a homework question. have you tried asking your classmates? Night Gyr 19:18, 8 April 2006 (UTC)[reply]

No, it's not a homework question. I'm a good faith editor, and I know this isn't the place to get h/w done. I'm learning C# by myself, and have made an adding machine before; but forgot the code. Computerjoe 's talk 21:06, 8 April 2006 (UTC)[reply]

Then it should be easier for you to write it the second time. Bubba73 (talk), 01:47, 10 April 2006 (UTC)[reply]

wouldn't it just be a matter of creating code for each button, so pushing a key puts a number-symbol onto the end of a string, then when an operation key is pushed the string is converted to a number and the specified operation is performed? it doesn't seem to hard to write if you know how to create button controls. I know java and C/C++, not C#, though, so microsoft may be pulling something different. Night Gyr 05:56, 9 April 2006 (UTC)[reply]

Yep. I need to know the code to transform e.g. TextBox1 and TextBox2 into a string. This has float.Parse in I think. Computerjoe 's talk 09:02, 9 April 2006 (UTC)[reply]

Er, turning the contents of a text box into a string? Should already be a string if it's in a text box. If you're really emulating a calculator (with graphical buttons to provide digits, particularly), you shouldn't be doing any string-parsing anyway. (Just handle the input yourself, forming

10x+d

x+d\times 10^{-n}

in response to a digit

d

.) Then format floating-point numbers for output only, retaining the number for further computation. In other words, you want to do as few data-conversions as possible. (You also want to be using double precision, probably.) --Tardis 14:58, 10 April 2006 (UTC)[reply]

Poincare's radiation paradoxes

Hey folks! I was just reading Olivier Darrigol's paper from the journal Isis on the Einstein-Poincare priority dispute, and I came across the phrase "radiation paradoxes" as an item of importance. What are these radiation paradoxes? I'm a layman, so I was hoping someone could explain it in ordinary english. Thanks in advance! 65.95.139.89 18:49, 8 April 2006 (UTC)[reply]

The very short version is that if you try to work out the equations of electromagnetism -- particularly for the propagation of electromagnetic radiation (ie light) -- for different observers travelling at different speeds, but use Galilean relativity (that is, the intuitive idea that the speed of an object moving at

\mathbf {v_{obj}}

according to one observer is

\mathbf {v_{obj}} +\mathbf {v_{obs}}

according to another observer in whose reference frame the first observer is moving at

\mathbf {v_{obs}}

) you will get different answers for different observers -- hence "radiation paradoxes". Postulating an invariant speed of light fixes this, but forces you to use a more complicated equation for relative speeds (albeit one that is very close to the Galilean one at low speeds). --Bth 19:26, 8 April 2006 (UTC)[reply]

Diseases

How many diseases affect the man most and the woman most? — Preceding unsigned comment added by 70.53.95.183 (talk • contribs)

Red/Green Colorblindness is overwhelmingly male, since it is caused by a recessive gene on the X chromosome, of which women have 2 but man have 1 (They have XY instead of XX). 21:14, 8 April 2006 (UTC)

I'm not sure how to answer this question. Men, for example, are incapable of contracting cervical cancer. And with regards to "how many", you can't really say "six" as an answer. Could you rephrase? Isopropyl

Isopropyl is right; for more examples, see also Sex and illness. Melchoir 22:40, 8 April 2006 (UTC)[reply]

Thousands of diseases affect people of different sexes differently statistically for thousands of known and unknown reasons. In other words, it may be more unusual for a disease to have exactly the same sex distribution of the population than to have at least a small sexual association. alteripse 02:07, 10 April 2006 (UTC)[reply]

Data compression?

I was wondering, are there any lossy text compression algorithms? he he... it would be a bit like censorship if you think about it.--Frenchman113 21:12, 8 April 2006 (UTC)[reply]

Ys, thr prbbl r sm lss txt cmprssn lgrthms. --GraemeL ^(talk) 21:16, 8 April 2006 (UTC)[reply]

Pitman shorthand is another one. Four candles, anyone? --Heron 21:31, 8 April 2006 (UTC)[reply]

A lossy text compression system wouldn't be very much use, but if you wanted to play, you could run text through an mp3 or jpg compression system, and see what came out - the results would probably show you why there really isn't one in the sense you mean it. For great justice. 22:04, 8 April 2006 (UTC)[reply]

you could use abbrev. to repr. words. They lose some data (i.e. gain ambiguity) but as long as context makes up for it, you can save space at min. qual. loss--same prin. as other lossy algos. Night Gyr 06:01, 9 April 2006 (UTC)[reply]

If you have Linux, rm * gives 100% compression. -- Filliam H Muffman 03:55, 11 April 2006 (UTC)[reply]
Another linux option... cat file | tr -d ' ' whichwilleffectivelycutoutallthespaces.thiswillgiveyoumaybea10%sizereduction,butyoucouldprobablystillmakeoutthetextright?

--Jmeden2000 15:17, 12 April 2006 (UTC)[reply]

Another question

Hate to be a nuisance, but how can I force WMP to save video that's being streamed from the web? I'm totally missing something here...--Frenchman113 22:31, 8 April 2006 (UTC)[reply]

Try asfrecorder, http://sourceforge.net/projects/asfrecorder/ 202.58.62.4 00:27, 9 April 2006 (UTC)[reply]

Projectile, Missile, and Rocket

What is the difference among these?Patchouli 23:15, 8 April 2006 (UTC)[reply]

A projectile is any object launched into the air by any given power source (includes asteroids, arrows, cannoballs, meteors, etc). A missile is a projectile launched by a human (in the modern sense, usually an explosive-bearing rocket). A rocket is a device powered by Newton's third law of motion (exhaust=action, rocket movement=reaction). Hope that helps.--Frenchman113 00:02, 9 April 2006 (UTC)[reply]

In a general sense, a missile is a general term encompassing all human-launched projectiles, including stones flung from slings and shells from battleship cannons, but in a modern military context, it's the subset of rockets that have their own guidance systems, i.e. guided missiles. Night Gyr 06:04, 9 April 2006 (UTC)[reply]

Thank you.Patchouli 10:58, 9 April 2006 (UTC)[reply]

Many people disambiguate rocket and, say, jet engines, by the idea that rockets carry their own fuel and reaction mass. -Fangz

April 9

latex in xfig diagrams

I'm trying to make a diagram in xfig which includes some LaTeX formatted text. I'm following the instructions here.

Here's what I do:

draw my diagram
make a text box with text "$\int f(x)\, dx$"
set the "special" flag to "special" of the text box
choose export, then select "combined PDF/Latex both parts", then export, resulting in two files intbox_t and intbox
change the filename of intbox to intbox.pdf; my system won't work without the extension
change the line "\includegraphics{intbox}%" to "\includegraphics{intbox.pdf}%", so account for the change in filename above
in my tex source file, I include the header "\usepackage{graphicx}"
I input the file with "\input intbox3.pdftex_t"
then I tell latex to do its work. It seems to find the file and import the pdf, but then it barfs with:

loading : Context Support Macros / PDF (2004.03.26)
) (./intbox3.pdftex_t <intbox3.pdf, id=1, 258.9675pt x 177.66376pt>
<use intbox3.pdf>
! Undefined control sequence.
\color ...vevmode \csname fi\endcsname }\@ldc@l@r 
                                                  
l.14 }}}}
         
?

I'm using an OSX system, using TeXshop frontend to pdflatex.

I'm a hair away from giving up. This is for a wikipedia article, so if you can straighten this out for me, you're helping grow an article. -lethe ^{talk +} 00:23, 9 April 2006 (UTC)[reply]

Are you using \input{intbox3.pdftex_t}? If you want to email me the sources I could have a look. I use TeTeX under Linux but it doesn't seem to be an operating system problem. Ans e ll 00:54, 9 April 2006 (UTC)[reply]

OK, I've sent an email. Thanks for taking a look. -lethe ^{talk +} 17:55, 9 April 2006 (UTC)[reply]

Another solution is to export the xfig doc in "LaTeX picture + epic macros" (or "eepic macros" if you need them). Then you have to \usepackage{epic} (or eepic), but everything is in LaTeX format from the start. So for the text you just put placeholders in the xfig doc, and then go into the exported source and hack the text in by hand. The biggest downside is that if you need eepic, it won't work with PDFLaTeX and you'll have to do the two-step process to get a pdf file, which may not have hyperlinks. --Trovatore 18:47, 9 April 2006 (UTC)[reply]

LASIK and losing vision

I overheard someone saying that you lose part of your vision or something like that when you have LASIK surgery, is this true?

Our article on LASIK might be helpful to you, in particular the Complications section. -- Daverocks (talk) 02:53, 9 April 2006 (UTC)[reply]

BMW Bluetooth

I have a BMW with bluetooth, and I had the code but I lost it. BMW says they dont have it and want $120 to retreive it from my car, is there any other way to get it? I used to use a motorola v600 and the code is in the phone, I just cant retreive it (I dont know how), how can I get the code?

Fortune cookie say: He who can afford BMW, can afford to get it fixed. --Zeizmic 15:19, 9 April 2006 (UTC)[reply]

Heh. But anyway, if you can get the code without paying, then so can anybody else. OMG CAR HAX!!!!1 Tzarius 09:40, 10 April 2006 (UTC)[reply]

I'm just waiting for the "Wikipedia - where car theives go for advice" story to crop up somewhere now. — ceejayoz ^talk 17:49, 13 April 2006 (UTC)[reply]

Try taking the phone to the dealer and ask him to retrieve the code from it...it'll probably be a lot cheaper and faster.. :) Jayant,17 Years, India • contribs 18:10, 13 April 2006 (UTC)[reply]

Cloning

Is it possible at this time to produce a clone of someone?

I think so, yes. According to the article on human cloning, ACT was the first to sucessfully clone a human embryo. There are many claims of success beyond the embryo stage, but none of them have been verified. --Bowlhover 04:54, 9 April 2006 (UTC)[reply]

No, not quite, but we are getting close. Part of the problem lies in defining "clone" in a consistent way, and the media has failed to do this. But I assume you mean "Is it possible to make a human being who would have the exact DNA as another." In a somewhat trivial sense, the answer to that is yes. We have long had the ability to perform artificial insemination in a culture dish. And one of the most frequent reasons to do this is to avoid conceiving children with an inheritable disease. By removing a single cell from the early zygote, and allowing that cell to grow for a while before (destructively) analyzing its DNA, we have created a clone of the original zygote. Many such clones can be made from these early embryonic cells and each of them has the potential of growing into a healthy human who would have DNA identical to the other humans who were derived from that same original zygote. But making a human clone from an adult does not yet seem possible with current techniques and understanding. Just convincing the early cell to make the initial divisions has been problematic. Developmental biology is not a simple field. In fact, it's in its infancy. Until we understand the numerous developmental hurdles and chemical cascades that determine human development, we wont be able to undertake this task without high risk. Once we do reach that stage of technological capability, the entire process will likely seem so incredibly obvious we'll be baffled at why it took us so long. Ande B 09:18, 9 April 2006 (UTC)[reply]

Yes, but I have a feeling that it's going to take us a very long time to reach that stage, certainly much longer than needed. The world's most advanced nation, the U.S., has prohibited federal funding for human cloning research. Some U.S. states have even banned all forms of human cloning. Religion got into the way of scientific research, just as it did in the past. --Bowlhover 17:35, 9 April 2006 (UTC)[reply]

The world's most advanced nation, the U.S.

(much coughing and spluttering and muttering about damn Yankees) ;) — QuantumEleven | (talk) 09:31, 10 April 2006 (UTC)[reply]

How accurate are the Heavens Above predictions?

In terms of time, how accurate are the Iridium flare predictions? I know my latitude, longitude, and elevation to within 30 m, so the errors in my position shouldn't affect the results too much.

I'm curious about this because I plan on photographing tomorrow night's magnitude -2 flare, using a 15-second exposure time. I'm going to use an accurate clock to tell me when to press the shutter button--there needs to be 7.5 seconds of exposure before maximum brightness, and 7.5 seconds after. --Bowlhover 04:42, 9 April 2006 (UTC)[reply]

I successfully photographed the iridium flare whose maximum brightness was at 21:17:08 (according to the Heavens Above prediction). Here is the 4.1-megabyte photograph--the flare is the streak of light in Cepheus, and to the left of the photo is Cassiopeia. I pressed the shutter button at 21:17:00, so the shutter opened at 21:17:02 due to the 2-second self-timer. It closed at 21:17:17. As you can see from the photograph, the flare was already very near its maximum brightness when the shutter opened. So the prediction was off by about 5 seconds. --Bowlhover 02:22, 10 April 2006 (UTC)[reply]

Nice work! Ande B 21:14, 11 April 2006 (UTC)[reply]

Tinted CD-Rs

I saw and purchased some tinted CD-Rs yesterday in Taipei. The writing surface of these discs is in bright orange or bright green (they are colored like highlighter marker pens) and they cost NTD6 each (less than US$0.20 cheap). Do they employ newer dyes? Or are they just ordinary CD-Rs with tinted polycarbonate plastics? -- Toytoy 07:15, 9 April 2006 (UTC)[reply]

I actually just saw one of those the other day for the first time. As you guessed, it's just tinted polycarbonate. Chapuisat 15:08, 11 April 2006 (UTC)[reply]

Open University Recommendation

Can anyone help in recommending a free Open University that allows under- 18 pupils to enjoy the studies of Mathematical Modelling and Theoretical Physics? I shall be deeply grateful for any suggestions. Luthinya 10:10, 9 April 2006 (UTC)[reply]

If you want an Open University, you're probably in the UK, but MIT has a lovely site over at OpenCourseWare, where lecture notes and readings and other materials are posted. Isopropyl 15:38, 9 April 2006 (UTC)[reply]

Angular Momentum

In a book I have read recently concerning the spin of subatomic particles, I have heard Max Born say that though particles do not actually have spin in the usualy sense of the word, yet they still behave as if they have angular momentum. I am afraid I have not been able to decipher this remark, and shall be grateful if anyone may help in understanding it. Luthinya 10:15, 9 April 2006 (UTC)[reply]

Subatomic particles do have angular momentum. They can rotate about a linear axis in three dimensions, with such rotation obeying conservation of momentum, affecting collisions (although not always the same as for molecules and solids; baryons and fermions are very different in this respect because of their different properties) and wobbling with gyroscopic effects including when rotation interacts with field effects such as electromagnitism. Particles also have quantum spin which is a quantum number which is completely disjoint from angular momentum. "Spin" was named after experiments with polarization suggested that the quantum number was similar to angular momentum. As a quantum number, spin has conservation laws based strictly on small or simple fractional multiples of integers. Note that the angular momentum of a low-mass electron is unlikely to ever have much of an affect on its behavior when compared to electrostatic forces. For nuclons, though, angualr momentum can be very significant. See, for example, Cold fusion#Current understanding of nuclear processes. --James S. 11:30, 9 April 2006 (UTC) This is a bad explanation for several reasons. Please see Spin (physics), Spin quantum number, and Angular momentum. --James S. 13:15, 9 April 2006 (UTC)[reply]

Ok, well.. There are a lot of levels of explaination that could be given here. The simplest, most common one is to describe spin as 'intrinsic angular momentum'. That is, an amount of angular momentum that is built-in to the particle, so to speak. So spin does work 'as if they have angular momentum', but it's a different property. (they can, however, interact. (Spin-orbit coupling) --BluePlatypus 01:49, 10 April 2006 (UTC)[reply]

Sheep

Can a human physically make a sheep pregnant by sexual intercourse?

No, in general, different species can not interbreed. (But he can try.) --James S. 11:17, 9 April 2006 (UTC)[reply]

But, but I can make it happen. It's actually doable.

Give me some sexually matured male sheep and female sheep. I can physically force the female ones to pregnant. In fact, they may just go pregnant with or without my efforts. -- Toytoy 14:30, 9 April 2006 (UTC)[reply]

See Hybrid and Horizontal gene transfer and HeLa (a single cell species created by humans from a human) for interesting examples of what is possible, and Category:Mythological hybrids for what people used to think was possible. WAS 4.250 14:44, 9 April 2006 (UTC)[reply]

Chimera (genetics) is also an interesting read. Isopropyl 15:36, 9 April 2006 (UTC)[reply]

Do I detect a sense of urgency in this question? I hope not. Phileas 06:19, 10 April 2006 (UTC)[reply]

astronomy - colour correction

In colour images taken of the night sky, do astronomers ever attempt to correct the colours to allow for redshift? Obviously this would be tedious, difficult and probably impossible where the redshift of objects is not known. However for something as large as the Orion Nebula, is this ever done? --Paul venter 14:34, 9 April 2006 (UTC)[reply]

The Orion Nebula is in our own galaxy, and therefore can be expected to have a negligible redshift. In general, quite a bit of processing is done on most astronomical images, and correcting for redshift would be relatively easy. See this link for information about how the Hubble Space Telescope does it. In any case, computing an object's redshift is relatively easy; if you have a spectrograph, you're most of the way there. -- Filliam H Muffman 03:14, 10 April 2006 (UTC)[reply]

You don't even need (expensive and time-consuming) spectroscopy; if you have good photometry at multiple wavelengths you can get a reasonable estimate from photometric redshifts. (We should have an article on them; maybe I'll add it to my to do list.) --Bth 07:17, 10 April 2006 (UTC)[reply]

Can we defeat radiocarbon dating?

Can we defeat radiocarbon dating? I think it is very possible.

Build a totally enclosed greenhouse similar to the Biosphere 2 (with positive pressure).
Buy lots of coal.
Grow Cyperus papyrus in the greenhouse using hydroponics equipments.
Burn the coal to provide ¹²C-rich CO₂.
If you need other organic fertilizers, grow alfalfa at first and use it as the fertilizer.
Make your papyrus with your ¹⁴C-poor Cyperus papyrus.
Let an expert create the forgery.
Hire an antique dealer to inform scholars.
Let them see the v1.0 fake which may not be good enough.
Let the antique dealer to ruin the deal.
Let the forged item sit in a bank safe for years.
Take your time to create and age your v2.0 fake to the desired status of corruption.
Let the scholars buy it.

I think you can always find cheap and aboundant materials that are not polluted by post-WW II radioactive fallout (e.g. antartic ice to provide water). Scientists can only conduct destructive tests on unwritten parts of the speciment. I guess you don't even need to make ¹⁴C-poor ink. I think it is possible to make something to defeat ¹²C and most other scientific dating techniques. You can mass-produce multiple copies of the forged document (each created and aged a little differently) and test them with all the tools available. The copy that can fool all tests will be released to the scholars. Maybe you can breed your own "ancient" Cyperus using DNA fragments extracted from real antiques. - Toytoy 16:09, 9 April 2006 (UTC)[reply]

I like it! Seems like it would be possible, but with your method the forgery would be just as old as the coal you bought (by C-14 dating). I'd add another step about regulating the C-14 concentration by adding outside CO2 to get just the right date you want for your papyrus to have died. -Snpoj

Yes, you're right. I'll build a window. It's easy to regulate the amount of ¹⁴C. You can build a window or buy some charcoal. You may also want to filter your coal burner because unfiltered smoke may contain too much sulfur. Anyway, I think it is very possible to cheat scientists. All you need is a great expert of ancient literature. You can open the window and harvest your Cyperus every 12 hours. Sooner or later, you'll get a batch of Cyperus that's dated to the desired time period. These grasses are growing fast! Maybe you can sell the unused but dated portions to other law breakers! :) -- Toytoy 16:37, 9 April 2006 (UTC)[reply]

But why fool scientists now if you can fool them thousands of years in the future? Why rewrite the past when you rewrite the future!? Using a mass spectrometer, isolate C-14, burn it and infuse it into the atmosphere of the dome. Now when the papyrus dies it will have a healthy stock of C-14 with which to pass the time. Eventually, in the year xxxx so much C-14 will have degraded as to appear that our Cyperus died just last year in xxxx-1! Now in the year yyyy documents written by us on the Cyperus back in 2006 will be found. The unsuspecting scientists will believe they must rewrite the history of xxxx with our falsification and we'll be laughing in our forgotten graves! -Snpoj 03:48, 10 April 2006 (UTC)[reply]

I don't think anyone claimed it to be impossible, either. But you leave out the problems with aging. There are no doubt chemical markers (e.g. various decomposition products) which can be used to distingush something which has aged normally and something which has been bleached or similar. Then there are of course all the other usual methods of detecting a forgery. I don't think radiocarbon dating is terribly important for dating documents either - from what I understand from reading bibliophile literature, old paper is in relatively good supply. --BluePlatypus 18:00, 9 April 2006 (UTC)[reply]

Unfortunately the problem you have is that C-14 is created from C-12 by solar raditation.

http://www.ndt-ed.org/EducationResources/CommunityCollege/Radiography/Physics/carbondating.htm Thus the ration of C-14 in your papyrus would still have the correct C-14. Now add to the fact that your Ancient language experts are few and far between. Most of them are scholars, and they all know each other. -Tollwutig 14:56, 10 April 2006 (UTC)[reply]

If you build a greenhouse at near sea level, and you burn fresh coal to produce fresh ¹⁴C-poor CO₂, solar radiation can do nothing. To create ¹⁴C, you need high energy cosmic ray that's only available very very high above.

You can always obtain genuine unused ancient papyrus or Chinese paper from antique dealers. In fact, many high-end Chinese art counterfeiter have their personal stockpiles of unused paper aged for at least a couple hundred years. However, if you have an endless supply of ¹⁴C-poor papyrus, you can mass-manufacture history-making documents and age them by a trial and error approach. If you take time and money to do it, you will have some really great speciments in a few decades that can fool almost everyone on Earth.

This method is surely difficult. An ordinary counterfeiter will not do it, but a determined government or religious group may have the will, expertise, time and resources to create something to support its own position (we own this land, we are better than you, our god was ...). -- Toytoy 15:41, 10 April 2006 (UTC)[reply]

I have an even better idea, I could just use my time mahcine to go back to 1192, and drop off a reem of printer paper in an easy to find location, then travel back to the future, and pick it up there after it's had a few thousand years to age, then write whatever the heck i want to on it — Preceding unsigned comment added by 64.12.116.74 (talk • contribs)

With your specifics I take you are discussing the recent Gospel of Judas release by National Geographic? If so you'll have a hard time finding someone who knows Coptic, there are what 5 people who can readily translate it?--Tollwutig 19:50, 10 April 2006 (UTC)[reply]

You're damn right. I am very skeptical to the NG's Gospel of Judas TV show. I think it is difficult to create such a scholar bait but that's not totally impossible. In my opinion, NG failed miserably by creating a two-hour-long show that does not interview reasonable skeptics. I mean they jump to the conclusion too soon or they want the audience to buy the theory that the Passion could be simply wrong.

Logically, you may also say the Gnostics had build a myth to counter other Christian sects or you may even say both sides lied when they talked about the death of Jesus. NG failed to present a more neutral POV with their dog and pony show. It didn't even say Jesus could turn himself to the Romans rather than asking Judas to betray him. The NG is telling a lousy detective story.

As to the "only five people on Earth could write ancient Coptics" statement, I really cannot disprove it. However, I am very skeptical. Let's say the text was created by a counterfeiter. If you put it down in ancient Greek, the expert pool will be much more larger and there will be more skeptical eyes to review your text. And by the way, I don't think ancient Coptics is some sort of regulated language. You don't need a license to learn it. You just don't see many college job offers. A determined person previously trained in related languages may learn the language from various sources. Logically, you may also say some Evil Theologist discovered a Medieval Coptic text that tells such a story. He hired an Evil Linguist and an Evil Scientist to rewrite the text to match 3rd century grammer and put it on a piece of 3rd century papyrus to make the text closer to truth. Did I ever mention the Black Helicopter?

Personally, I have only seen statements such as: GoJ said Judas was not a bad guy. The existence of the GoJ was proven by ... . I did not see them to advertise other previously unknown findings from the GoJ. If you unearth a document like this, I expect to learn some unknown things that are trivial in scope such as "The Apostle Peter had ulcer." or things like this. I don't think all genuine documents shall carry such information, but a forger may invent a story with all known facts and insert just one think to prove his point. After all, I think NG failed to take a more neutral stand in this case. It only took me minutes to devise a way to counter ¹⁴C dating. To a determined expert with money to burn, it could be even easier. The NG shall be more careful and skeptical with their discovery. -- Toytoy 00:31, 11 April 2006 (UTC)[reply]

Frankly, you seem to have a little bit of a chip on your shoulder about this, Toytoy. If it makes you feel any better, just because the document is authentic doesn't mean you have to believe what it says. Why not just say "this is what the Cainites believed but they were full of crap", instead of camping out on the grassy knoll? --Trovatore 00:46, 11 April 2006 (UTC)[reply]

I believe some questions can never be fully answered even if we travel back in time with all kinds of evidence collection tricks and tools. If we cannot fully answer today's questions, how can we be so sure about yesterday's unsolved mysteries?

However, I think some scholars are extremely gullible. I have first hand experience with an easily debunkable pre-Columbus historical discovery. Some scholars, I mean some of them, are just too eager to believe.

Based on what I have seen, I believe the QC Dept. of the National Geography Society failed to do their job. Instead of showing us non-experts a less loaded version of the story, they made the show as if it was almost the truth. It didn't answer some trivial questions. I think it is natural for some earlier sects to pro Judas and some others to bash Judas. A skeptic may require more solid evidence before jumping on the band wagon. Too willingly to accept can lead to miserable mistakes. Do I have to make up a text that says "All apostles other than Judas betrayed Jesus. They took the money and framed Judas"? If you're willing to believe, someone somewhere may be willing to cook you some tasty truth.

If the text was genuine, it would be more insightful to study the societal structure of the writers rather than to ship us another version of the truth. I mean the original Gospels were created by the 1st generation followers. By the time the stories travelled to Egypt, it must had been modified a little bit here and there to please local Christians. It's like making locally adapted versions of Hamlet for 17th century Japanese or 18th century Persian viewers. -- Toytoy 07:02, 11 April 2006 (UTC)[reply]

Popular presentations of academic subjects, particularly on TV, tend to be slanted towards providing some sort of "narrative" (often, as in this case, "everything you thought you knew is (probably) wrong", though "person X's wild speculation is vindicated centuries later because it happens to sound a bit like what we now understand" is also popular), and have been for decades now. All that's happened is that you've seen one that touched on a subject that you have some knowledge of, or at least strong feelings about. Almost every show like this makes people who know the field feel the way you do right now. You should probably bear that in mind next time you watch one.

On the other hand, I'm fairly sure I was aware of these ideas about Judas having been around in some of the now-extinct branches of Christianity well before this flap, so I'm not sure there isn't something in it. --Bth 07:20, 11 April 2006 (UTC)[reply]

Inductance

How to make 1 henery inductance coil?

Did you check induction coil? I don't know what a Henry or Henery induction coil is. --

Mac Davis] ⌇☢ ญƛ. 12:46, 10 April 2006 (UTC)[reply]

The henry is the SI unit of inductance. --Bth 13:25, 10 April 2006 (UTC)[reply]

Here's a site which discusses design and construction of coils. EricR 14:02, 10 April 2006 (UTC)[reply]

Self of Solenoid

L= (m0mr S N*N) / l An above Equation can use to calculate a self of a coil with the defined length and l>> D( D : is a diameter of the coil, S: Surface of coil ; S= (1/4)*4*3.14 D*D) m0= 4*3.14*10-7 ( here mr=1, a core is air ) Supposed: S=4cm2 = 4*10-4 m2 N= number of turn ( round) l= length of coil= 10cm=0.1 m For L =1 H , we must have N= 4461 rounds --User:Ngocthuan 06 18:25, 10 April 2006 (UTC)[reply]

electrical potential of the sun

My question is based on the following, which is from "Beyond Velikovsky", by Henry Bauer, page 59. He says that Velikovsky attributed some things to electromagnetic forces between astronomical bodies. In particular, in 1952 astronomer Donald Menzel calculated that the potential of the sun would have to be 10^19 volts to account for some of Velikovsky's claims (also in Worlds in Collision), which Menzel said is impossible. In 1960 physicist V. A. Bailey (unaware of Velikovsky's work and Menzel's calculations) proposed a theory that had (as a consequence) a potential of 10^19 volts for the sun. Bailey found a mathematical error in Menzel's calculations.

I have two questions: (1) what became of Bailey's theory? (2) What is the electrical potential of the sun (if it is known)? Bubba73 (talk), 01:42, 10 April 2006 (UTC)[reply]

Take a look at Electric Universe. ☢ Ҡi∊ff⌇↯ 02:10, 10 April 2006 (UTC)[reply]

I can't find any mention of Bailey's theory there, or the Sun's potential. Is Bailey's theory part of the Electric Universe theory? Bubba73 (talk), 02:18, 10 April 2006 (UTC)[reply]

"[The "electric star" model proposed by Ralph Juergens in 1970s (in Pensee II, IX & X, SIS Review, & Kronos) and revived by Wallace Thornhill in The Electric Universe (1998), part of his "holoscience" project, (in which the Sun is a non-convecting, isothermal ball of plasma powered by infalling galactic electrons and many craters in the Solar System are the result of gigantic electric discharges, etc.) [as deus ex machina] cannot rescue the "polar configuration" from its fatal flaws because the model is a non-starter. It is disproved by practically everything known about the actual behavior of the Sun and heliosphere. This was first explained by this writer in Kronos X:3, 1985, pp. 15-23, and recently in more depth on e-mail list-serves by Robert Grumbine, Karl Hahn, Burch Seymour, Tim Thompson, and Wayne Throop. Thornhill either ignores or dismisses all the negative evidence such as (i) the absence of x-rays in coronal holes (which should be produced by infalling electrons for which no evidence exists beyond the wishful thinking of Thornhill and star-struck acolytes such as Amy & Mel Acheson writing for Thoth and Atlantis Rising, and Don Scott, an electrical engineer, who in parroting Ralph Juergens in Kronos IV:4, 1979, also fails to understand the importance of the Reynolds Number in defining turbulence in photospheric granulation.), (ii) the proof that granulation in the Sun's photosphere is an expression of convection, (iii) the mere existence of the solar wind in which no inflowing electrons have been detected, (iv) the absence of characteristic particles from the nuclear fusion claimed to occur in the photosphere, etc., etc. The model lacks rigorous mathematical support. No one has ever shown that the electric charge required to produce the cited craters, e.g., Aristarchus on the Moon, is feasible, while rigorous mathematical modelling to explain the high temperature in the Sun's corona, a favorite anomaly cited against standard theory, in conventional terms is progressing steadily. The simplistic analogies to plasma and electrical discharge phenomena that are invoked to support the model [as in Talbott & Thornhill's Thunderbolts of the Gods (2002)] cannot nullify the verdict of the overwhelming negative evidence and serve only as an example of invincible ignorance, showing the proponents do not know, for example, the difference between a plasmoid and a pair of opposed lotus blossoms used by the Greeks to represent the thunderbolt held by Zeus. Other examples of so-called electric discharge effects on planets, asteroids, and satellites (such as Europa) can be explained by conventional means without invoking cosmic electricity.]" from AN ANTIDOTE TO VELIKOVSKIAN DELUSIONS WAS 4.250 12:46, 10 April 2006 (UTC)[reply]

http://www.asap.unimelb.edu.au/bsparcs/physics/P000031p.htm doesn't seem to identify this theory with BAILEY, Victor Albert although it seems to be a list of all his papers. WAS 4.250 12:46, 10 April 2006 (UTC)[reply]

This page of notes for a Velikovskyite essay references a Nature paper by Bailey from 1960 which isn't on that list: vol 186, p508. Not in any online archives that I can see, annoyingly. But it's probably the paper in question here, if anyone can get to a good library. --Bth 13:16, 10 April 2006 (UTC)[reply]

Science. RF Power Measurement.

Dear Sir/Madam,

I wish to know in detail the method of RF power measurement in different modes such as a. Timeslot Mode b. Continuous Average Mode c. Buffered Continuous Average Mode d. Burst Mode & e. Scope Mode

Kindly help.

Regards Pavan

Our article on Radio frequency might be of interest to you, as well as this page about measuring RF power. -- Daverocks (talk) 09:02, 11 April 2006 (UTC)[reply]

Website Hosting

Is it possible to host your own website on your own computer? Would this require a fixed IP address? Is it possible to demand a fixed IP address from your ISP? --Username132 (talk) 05:22, 10 April 2006 (UTC)[reply]

To answer my own questions, yes it is possible and a fixed IP is not necessarily necessary. http://www.no-ip.com for example, offers ways around dynamic IPs, although I don't really understand how it works (anyone else?). Some ISPs offer a fixed IP as standard or for an extra fee, or even not at all, but some users report that they have had the same IP for up to two years even with switching equipment on and off multiple times. What is it that dictates when a persons IP is changed?

Would an admin on this website be able to compare the IPs used to make my first ever edit and this edit I'm typing now, for me? There may be other IPs inbetween due to editting done at university accomodation. Thanks :) --Username132 (talk) 06:31, 10 April 2006 (UTC)[reply]

I've used http://www.dyndns.org which gave me a domain name that I could attach to my (current) IP. I also had a program running on my computer that constantly updated the information about my current IP to dyndns, keeping the domain name attached to my computer. I would assume no-ip works like this, too. My current hardware firewall is also capable of updating its IP to dyndns by itself. –Mysid 06:40, 10 April 2006 (UTC)[reply]

Thanks. I have the option of

a) hosting through the WinXP machine my mum uses; or

b) hosting through a Proliant 3000 server with Fedora Core 4 installed which would then have to relay internet access to mum's computer as required.

Is setting up a web server difficult? I'd like to be able to receive email to my domain name aswell. --Username132 (talk) 07:24, 10 April 2006 (UTC)[reply]

Setting up a web server is not trivial - especially as you want to configure it so that it's secure against attacks - but with a bit of knowledge and lots of reading of help documents, it should be doable. Check out Apache HTTP Server, the most popular (and free!) webserver available. If you want to receive e-mail through your domain, you need to also run (at the same time) an e-mail server on your computer.

A more general note - is there a reason why you want to set up your own server? There are plenty of hosting sites which offer you ample web space, already set up, for a modest monthly fee - most of these have e-mail facilities, too. Obviously, it's up to you, I'm just wondering if you're not going to more hassle than you need to. Also, you need to make sure your server is on 24/7, and that your internet connection can handle the outgoing traffic. For instance, an ADSL connection can only handle very limited outgoing traffic, you can easily saturate your link if you are serving large files or many users. Just something to think about. — QuantumEleven | (talk) 09:28, 10 April 2006 (UTC)[reply]

Admins can't see your IP, only developers and those with checkuser access can. If you want to see what your public IP is, go to DNSstuff.com. -- Finlay McWalter | Talk 14:39, 10 April 2006 (UTC)[reply]

I see. I wanted to know what my IP was a few months ago and I don't think there's anyway to do that except contact a forum where I posted. I'll try somewhere else. --Username132 (talk) 16:42, 10 April 2006 (UTC)[reply]

To see your IP address as the Wikipedia servers see it, click here and wait ten seconds. Note that this logs you out of Wikipedia, so you'll have to log back in afterwards. —Ilmari Karonen (talk) 12:14, 11 April 2006 (UTC)[reply]

Some questions about C programming.

Well here are some of my doubts about some basic concepts of C programming. I have divided them in different queries.

QUERY 1)

i have two programs prg1 and prg2 as follows

//prg1 main() { int i,j,k; }

//prg2 main() { int i; }

First i compile (not run) prg1, then i compile prg2. Now, after the compilation of prg2 is over, what happens to the space which was reserved by variables like j and k? As we have not used memory allocation functions, does that memory get freed on its own?

If you don't run either of these programs, the memory used by them isn't relevant. The compiler certainly allocated some memory to deal with your source code, and probably had the names "i", "j", and "k" written down somewhere (except not "j" and "k" for prg2, of course!). But once you've compiled them, the compiler has exited and all that memory has been long since released to the operating system. --Tardis 18:30, 10 April 2006 (UTC)[reply]

A second question about this same query, in any of the above programs, when i would print the values of any variable i,j or k, a random or garbage value would be printed. But wat is the basis of that random value? I mean some logic would have been built up in the writing of the code for the functions like rand() srand(), etc. So wats the logic there and also here?

Garbage values and random values are totally different. Random numbers are supposed to be evenly distributed and to have no pattern. Garbage probably will have a pattern, but not a dependable or useful one because it's just what happened to be left over from the last program to use that memory. —Keenan Pepper 16:46, 10 April 2006 (UTC)[reply]

Variable declarations in C literally assign a name to a chunk of memory. That physical memory already existed (as in silicon), and had something stored in it: possibly all 0s, or maybe the hex pattern 0xDEADBEEF, or part of the Wikipedia logo. The point is, you have no control over it, so you shouldn't assume anything about it. --Tardis 18:30, 10 April 2006 (UTC)[reply]

QUERY 2)

Now this one is about arrays. consider the following statement,

int a[x]; //x is a valid no., i.e non-negative, etc. etc.

now wat is the limit of "x", wat is the maximum value of "x" which i can use? Or does it not have any limits?

First, note that in standards-conforming C, x must be a compile-time constant; not even

const int x=10;

will work. But assuming you didn't mean a variable "x" but just some quantity, Keenan's prior comment below is (mostly) right. --Tardis 18:30, 10 April 2006 (UTC)[reply]

Secondly, if "x" has a limit, on what does it depend? Does it depend on the type of array, like here its an integer array, so does it depend on the type of the variable defined?

It depends on how much memory is in the computer you run it on. If it's too big, it will compile, but when you run it the memory allocation will fail and your program will crash. —Keenan Pepper 16:48, 10 April 2006 (UTC)[reply]

It only depends on the type of the array in that 5 doubles may take up more space than 5 shorts. Also, if it's initialized, or if the operating system/executable file format require it, the memory may become part of the executable file, and perhaps may be part of the compiler's memory space. Then it would fail to compile, or it might fail to be written to disk for disk space reasons. Beyond that, it's restricted by the data type of array indices. In Java this is int, but in C it might be size_t instead (check a book). --Tardis 18:30, 10 April 2006 (UTC)[reply]

Explore your system. Make files a10000.c, etc:

a10000.c is void main(){int a[10000];printf("10000\n");}
a100000.c   void main(){int a[100000];printf("100000\n");}
a1000000.c  void main(){int a[1000000];printf("1000000\n");}
a10000000.c void main(){int a[10000000];printf("10000000\n");}

Run. On MY system:

 -> ./a10000
10000
 -> ./a100000
100000
 -> ./a1000000
1000000
 -> ./a10000000
Segmentation Fault (core dumped)

On unix, now see the ulimit command. Explore variations on the theme, try long instead of int, etc. Contemplate the implications for portable programming. GangofOne 22:08, 10 April 2006 (UTC)[reply]

main() should return int, not void. —Keenan Pepper 00:03, 11 April 2006 (UTC)[reply]

QUERY 3)

This one is about memory addresses and pointers.

Consider following:

int i; printf("%u",&i);

Now, whenever the address of "i" is printed, its always less than 65524 (or some value near that). Why is it so? even if many variables are created, each variable's address value would be less than 65524. Why is it so? Is it because of the reason, that the disk segments are always divided in sizes of 65524 units?

First, pointers are properly printed with the '%p' conversion specifier. It has nothing to do with disk organization at all; perhaps the best answer is "don't print pointers because they won't mean anything". Pointer values will differ between different systems, will differ because of compiler choice or different compiler options, may differ between different runs of the same program (simultaneously or in sequence), and don't have a well-defined association with any particular point in physical memory (see virtual memory for more on that). As a stab at answering your question, 65524 is very close to

2^{16}=65536

, automatic variables are typically located on the call stack, and such stacks often grow downwards in memory; perhaps you have a 64K stack, and your pointer is (for any of a variety of reasons) relative to the bottom of that stack's memory area. --Tardis 18:30, 10 April 2006 (UTC)[reply]

Explore your sytem. while(i<1000000}{printf("%p ",&(i++));) This will generate another question in your mind. Write a program to answer it. This will generate another question... Repeat until (2038 AD). GangofOne 22:08, 10 April 2006 (UTC)[reply]

the structure of a dimerized pair of thymine molecules in a chain of DNA

could you please draw me this structure?

Can you use Google Image search? --Tardis 18:35, 10 April 2006 (UTC)[reply]

car audio - necessity of a capacitor

i was considering getting a small subwoofer for my girlfriends car to improve the sound quality. we listen to the music loud sometimes, but i mean it doesnt have to be ridiculously loud, just sound a little clearer when the volumes up and hear the bass tones a little better. anyway i talked to my dad about this because his neighbor runs a car audio store, but its a 'pimp my ride' kind of place (hes from romania). my dad said that it will need an amp and a capacitor. i know ill need an amp but do i really need a capacitor for a small subwoofer? i feel like i cant trust his opinion because his last car had a tv that slid out of the dash, this ridiculous sound system (my dad doesnt even listen to music) that soudned terrible when it would be put up loud to impress you, and vertical doors (he now admits the vertical doors were a mistake) anyway im sure ive seen many cars with subwoofers and no capacitors. my question is at want point do you have to install a capacitor, and for a small single amp will i need one? modesty 22:02, 10 April 2006 (UTC)[reply]

The purpose of a Cap is, like in any load circuit, to buffer power between a source and a load. A cap allows the voltage drops from the battery or alternator to be filtered out, which is important if you are running a lot of power. If the amp is running only 200-300W RMS (likely for a single sub 10-12") then there is generally enough capacity in the battery and alternator, so a big external cap is superfluous. Once you get past 500 WRMS is when you see issues with voltage drop along the wiring, and overloading of alternators and batteries (to the point of destruction) so extra provisions (a cap is among them, but shouldn't be the first) may be needed. --Jmeden2000 15:36, 11 April 2006 (UTC)[reply]

thank you --modesty 19:11, 11 April 2006 (UTC)[reply]

"The Critter"

I was reading a book about the Vietnam War the other day and a section of the book referred to the portion of the war in Laos. The author of the book referenced a certain animal that one of the other Americans had as a pet. For a long time nobody knew what the animal was called until one of the people stationed there happened to see the animal "Critter" on a Laotian postage stamp with the name "Panis Auritas". I can find no information on this animal.....I did find a picture of the postage stamp but no "Critter". Can anyone help with this information search.--67.98.38.212 22:53, 10 April 2006 (UTC)Benny[reply]

so what was on the postage stamp? alteripse 22:56, 10 April 2006 (UTC)[reply]

It looks a lot like a Pangolin to me -84.9.46.44 23:14, 10 April 2006 (UTC)[reply]

...which is genus Manis. I suspect a typo somewhere down the line. There is such a thing as a golden pangolin (though I note it's not listed in the Pangolin article), which might well have something like Manis Auritas as its taxonomic name. Grutness...wha? 02:31, 11 April 2006 (UTC)[reply]

April 11

Electromagnetism and force?

I have read in some places and seen some examples that electro-magnetism , specifically ionised air and static electric fields can move objects of any kind of matter. and also is the radiation pressure of light [which i know can move matter as have read article in scientific american on it] electromagnetic. How does it work if it does. I think it does as have read an interesting article on it. Am looking into it as a skeptical answer to poltergeist phenomena. this is the interesting article. it is about an electrostatic wall

".7 CASE STUDY - LARGE PLASTIC WEB ELECTROSTATIC PROBLEMS, RESULTS AND CURE, D. Swenson, 3M Company Tremendous static charge generation on a plastic web causes unique physical phenomena and special problems. Solution was simple and cost effective.

David Swenson of 3M Corporation describes an anomaly where workers encountered a strange "invisible wall" in the area under a fast-moving sheet of electrically charged polypropelene film in a factory. This "invisible wall" was strong enough to prevent humans from passing through. A person near this "wall" was unable to turn, and so had to walk backwards to retreat from it.

This occurred in late summer in South Carolina, in extremely high humidity. Polypropelene (PP) film on 50K ft. rolls 20ft wide was being slit and transferred to multiple smaller spools. The film was taken off the main roll at high speed, flowed upwards 20ft to overhead rollers, passed horizontally 20ft and then downwards to the slitting device, where it was spooled onto shorter rolls. The whole operation formed a cubical shaped tent, with two walls and a ceiling approximately 20ft square. The spools ran at 1000ft/min, or about 10MPH. The PP film had been manufactured with dissimilar surface structure on opposing faces. Contact electrification can occur even in similar materials if the surface textures or micro-structures are significantly different. The generation of a large imbalance of electrical surface-charge during unspooling was therefor not unexpected, and is a common problem in this industry. "Static cling" in the megavolt range!

On entering the factory floor and far from the equipment, Mr. Swenson's 200KV/ft handheld electrometer was found to slam to full scale. When he attempted to walk through the corridor formed by the moving film, he was stopped about half way through by an "invisible wall." He could lean all his weight forward but was unable to pass. He observed a fly get pulled into the charged, moving plastic, and speculates that the e-fields might have been strong enough to suck in birds!

The production manager did not believe Mr. Swenson's report of the strange phenomena. When they both returned to the factory floor, they found that the "wall" was no longer there. But the production workers had noticed the effect as occurring early in the morning when humidity was lower, so they agreed to try again another day. The second attempt was successful, and early in the morning the field underneath the "tent" was strong enough to raise even the short, curly hair of the production manager. The "invisible wall" effect had returned. He commented that he "didn't know whether to fix it or sell tickets."

- Bill Beaty

It later claims that this could be ionized air? how would this work? Robin

The story was made up. --

Mac Davis] ⌇☢ ญƛ. 01:21, 11 April 2006 (UTC)[reply]

Here's the origianl onlien, it was easy to google. http://www.amasci.com/weird/unusual/e-wall.html which references http://www.esdjournal.com/articles/final/final.htm , with pictures. GangofOne 02:14, 11 April 2006 (UTC)[reply]

FYI amasci.com is the site of User:wjbeaty, mentioned above.

Uuuuuum so now we have established that i didnt make the story up and its from a competant source, exactly how would it work? or am i just gona get accused of fraud again instead of getting the answer i asked for? I thought thats what this part of the site was for. Robin

Actually, you are going to be accused of being unable to properly respond. I moved your comment from the bottom of the page to this section. --Kainaw ^(talk) 15:38, 11 April 2006 (UTC)[reply]

Those aren't authoriative sources. This Beaty character seems to be a crackpot as well. His page is linked to by crank.net. What else need I say? --BluePlatypus 16:56, 11 April 2006 (UTC)[reply]

That's interesting. I know Bill Beaty's site, and I wonder whether crank.net listed him as an "anticrank" or a "crank". Could you give me the context for the link that you found on crank.net, please? I tried the obvious Google searches like "beaty site:crank.net", but without success. I spend a lot of time battling real cranks on Wikipedia, and IMO Bill isn't one of them. --Heron 19:23, 11 April 2006 (UTC)[reply]

The answer Robin is looking for can be found in human psychology, not physics. Humans mispercieve things all the time. Humans misreport things all the time. "How would it work?" It doesn't. It can't. Wouldn't it be cool, useful, and a source of immense profit if it existed? Of course it would. The actual profit here lies in selling books and ads on sensationalistic sites. Always follow the money. WAS 4.250 17:37, 11 April 2006 (UTC)[reply]

Thank you for a civil reply. Actually if you study the evidence, and arthur c clarke did in his book "world of mysterious powers" not all poltergeists can be put down to misunderstanding, illusion and fraud. Secondly their seems to be many effects that can do things described in some poltergeist cases. I have been told electromagnetic fields, ultra and infra-sound, ionizing radiation,radiation pressure and static charging can shoot things about. But the complete expulsion of the case i mentioned as fraud without a proper incquiry bugs me. It seems like a genuine case. and remember ball lightning was thought to be non-existant by scientists at first but lo and behold http://physicsweb.org/articles/news/10/2/6 , http://www.newscientist.com/article/dn1720.html in fact one of these thinks that poltergeists and them may be completly related natural phenomena. not paranormal or magical or spiritual, just misunderstood. And the only bill beaty articles i can find on crank .net are critisms of over skeptical science, no listing of his site on either science, paranormal, electromagnetism, or antigravity pages which he should be listed under. Robin 22:45 april 11th

I toss this out as speculation. Since the fields where so high and the 2nd guy felt crackling over his skin, maybe the effect was physiological. Maybe the fields where so high they were interfering with the action potentials of his nerve-muscle synapses. He said he couldn't turn around , he had to back out. Lost control of some muscle groups. This could be new information for the biophysics journals, if it were followed up with more testing. --GangofOne 23:30, 12 April 2006 (UTC)[reply]

Eusing Free Registry Cleaner

Does anybody have experience of using Eusing Registry Cleaner? My registry must be in need of serious cleaning out but I know that tinkering with one's registry is a dangerous activity, so I'd really want to know I can rely on any software that's going to effect it. Casual reviews much appreciated. --bodnotbod 01:25, 11 April 2006 (UTC)[reply]

If in doubt, always make a full backup first (open regedit, File -> Export, and make sure to select "All" as "Export range"). Then make small, incremental changes, restarting your computer between changes to ensure it still works. I have no familiarity with the program you mention, but check if it has a backup or undo option - most registry editors do. But, in any and all cases, make backups! :) — QuantumEleven | (talk) 06:16, 11 April 2006 (UTC)[reply]

This one looks OK (softpedia give it a clean rating though like Quantum I have no direct experience of it), but you're right to be cautious; the whole malware arms race has led to increasing amounts of malware masquerading as anti-malware tools. --Bth 10:12, 11 April 2006 (UTC)[reply]

The software claims to back up for you (or offer a restore point), but I shall follow your backup idea as best practice, thank you. Anyone with direct use of it? Oooh! ALternatively, can anyone recommend a highly regarded open source app for the same sorts of things? --bodnotbod 13:03, 11 April 2006 (UTC)[reply]

Constructivist learning theories

Does anyone know of exmaples of cognitive and social constructivist learning theories? i understand the concepts but need to exmaples to understand them clearly.

There is a very large selection of pedagogies (approached to teaching) that trace their origin to constructivist learning theories. At the base level an approach that uses hands on, discovery learning, can be considered constructivist in origin (students being the architects of their knowledge). There are many sophisticated examples (try doing a google search for constructivist pedagogy). One example I am familiar with is Covis. -Fermion 02:17, 11 April 2006 (UTC)[reply]

Yahoo! and computing services

The first page of the Yahoo! article states that Yahoo! is a "computing services" company. However, the provided link, computing services, seems to be a redirect to outsourcing. I was hoping to learn from the article what Yahoo! does, since I'm under the impression that they "run a website". I assume that the outsourcing link is inaccurate? -- Creidieki 02:29, 11 April 2006 (UTC)[reply]

The outsourcing link is accurate. Yahoo! hosts and maintains one of the e-commerce web sites for one of the companies that I work for. So we outsource the work to them. They do this for lots of companies. I'm not real familiar with the company and its services but they do perform at least some outsourcing. Here's the address for that service: http://smallbusiness.yahoo.com/merchant/ Dismas|^(talk) 04:17, 11 April 2006 (UTC)[reply]

I believe Yahoo! is also an internet service provider and provides it's own search engine. StuRat 22:29, 11 April 2006 (UTC)[reply]

Could you contain the current from a lightning strike

If you ionized the clouds (somehow), would it be possible to store the current from an lightning stike, given the amount of power discharged by them?

Your terminology "store the current" isn't what I think you mean. I think you mean "store the charge". While you could store some charge from a lightning strike, it would be very little of the overall charge. To date, devices that store charge require time to store up a charge. Lightning happens so quickly that there is no time to store much of the charge. However, it may be possible to steal a little charge from the clouds over time. There is a clear difference in charge between the top of tall buildings and the bottom. It isn't a huge amount, but it may be enough to trickle charge a battery. I've often considered doing an experiment with a lead on top of my offfice (13 floors) and a lead on the ground. The problem is that I don't have easy access to the roof and I'm sure someone would get upset if I hung a cable from the roof to the ground. But, you are free to try it. You may be able to do the same with a kite, using insulated wire for the 'string'. --Kainaw ^(talk) 13:37, 11 April 2006 (UTC)[reply]

Sorry, I must object. Flying a kite where there is possibility of lightning strike is potentially lethal. We all know Benjamin Franklin did it and became famous for it, but he was lucky. He was smart enough to know to use a silk thread (a nonconductor) for a distance to the cotton thread that went to the kite. The cotton , when wet, was a conductor, was connected to the famous key. He did NOT hold the cotton thread. He held the silk thread that was tied to the cotton thread, according to what I understand. I recommend some library research before messing with lightning. Trying to store the charge of lightening has been tried and done, by Franklin, but it is not practical. Read all about it first. No point in dying redoing 18th century science experiments. GangofOne 23:35, 11 April 2006 (UTC)[reply]

Thanks...and no I won't fry myself.

I did not say "fly a kite in a thunderstorm". I suggested that a kite be used to get an electrical lead off the ground to see if there is enough potential between high altitude and the ground to charge a battery ... when lightning is not present. As for storing the charge, there is much doubt that Franklin performed such an experiment. He flew a kite in the rain (after Thomas d'Alibard did a nearly identical experment with a tall iron rod). Then, there were many failed experiments around the world with lightning rods and jars of various substances. Many house fires followed. --Kainaw ^(talk) 23:46, 11 April 2006 (UTC)[reply]

Linux system keeps setting clock time wrong

I am running a Fedora Core 3 Linux system with Gnome 2.8. Every time I power up the system, its clock is at the wrong time, it's usually about 40 minutes in the past. I've tried setting the correct time with both date and hwclock but that only helps for the current session, when I reboot the computer the clock is at the wrong time again. Is it some weird service I'm running or is it a bug? I usually have fairly long uptimes, up to over a month, might this have something to do with it? How would I go about diagnosing it? JIP | Talk 06:42, 11 April 2006 (UTC)[reply]

Fedora might be synchronising the clock with an NTP time server every bootup. I haven't used Fedora on a day-to-day basis, but quite a few distros seem to do that. Check the ntpd service and if it's starting on bootup. -- Daverocks (talk) 09:07, 11 April 2006 (UTC)[reply]

Maybe try the BIOS? - mako 09:14, 11 April 2006 (UTC)[reply]

I've had (acutally, have) the same problem. It is caused by hwclock (see man hwclock). On my previous install I fixed it by rm /etc/adjtime, but I think that removing the --adjust parameters when hwclock is loaded should fix it as well. —Ruud 11:01, 11 April 2006 (UTC)[reply]

Another possibility is that the hardware clock is bad. They don't last forever. StuRat 22:16, 11 April 2006 (UTC)[reply]

But this is a fairly new system. I only bought it fresh from the store, assembled from off-the-shelf parts (new, not used) a year ago. JIP | Talk 15:36, 12 April 2006 (UTC)[reply]

The next step in diagnosis is to note exactly in what way it is bad. Is it always shifted by a fixed amount from the correct time? Is it always a particular date, like January 1970? Is there some other pattern? Notinasnaid 18:38, 12 April 2006 (UTC)[reply]

It is always shifted by a fixed amount of time (approximately 40 minutes in the past). JIP | Talk 13:27, 13 April 2006 (UTC)[reply]

Is ntpd running and if so whats its server list set to? it sounds like you may be syncronising off a bad time server. Plugwash 13:48, 13 April 2006 (UTC)[reply]

ntpd was not running. I activated it and set it to connect to ntp1.kolumbus.fi. This fixed my date and time settings. But as for rebooting, I am still not sure, because I use my company's private DNS server, which is only available through a PPTP connection, which is not started at bootup. So I fear that when I reboot the system, ntpd will not be able to find the NTP server, and will just quit, leaving my system back to the incorrect time. JIP | Talk 19:04, 13 April 2006 (UTC)[reply]

Timing Diagram

Hello,

I would like to write an article on Digital Electronics Timing Diagrams.

I have found a stub: wiki/Timing_diagram, but this relates to the new UML 2.0 Timing Diagram.

Where should I start my article.

Regards,

Mark

If there are two clearly different subjects that could fit into a title it can be handled using the diambiguation guidelines. Basically with two articles, you put links up the top of each page, explaining its context, and directing people looking for the other context, to the other page. A likely target for starting your article could be Timing diagram (electronics), as a suggestion. Ans e ll 09:01, 11 April 2006 (UTC)[reply]

UML Aggregation and SQL

I've been set the task of implementing a database schema given in UML as a MySQL database. In terms of design, what does the composition/aggregation relationship on the UML diagram translate to in terms of the tables required? The specific problem is the classic "library" system - there is a table Book which has the book details, then a relationship to an entity BookCopy, which has only one field listed. Is this extension, or inheritance, or neither? - does the arrow imply a foreign key? There is then another entity with the aggregation symbol - LoanedCopy. Could anyone give any advice on the structure of this, or a pointer to somewhere which has a decent tutorial covering UML -> SQL.

Cheers. QmunkE 12:54, 11 April 2006 (UTC)[reply]

It sounds like there would be a one-to-many relationship from the Book table to the BookCopy table. Perhaps each copy has a unique serial number ? In that case that would be the primary key to the BookCopy table. The ISDN would be the primary key in the Book table and also a foreign key column in the BookCopy table. The LoanedCopy table would be similar to the BookCopy table, but would also have info on who checked out the books, when they checked them out, when they returned them, etc. StuRat 22:09, 11 April 2006 (UTC)[reply]

Spacetime

Could anybody popularly explain the concept of four dimensional spacetime?

Time is just a dimension - like depth, width, and height. The best explanation I've heard is the "flatworld" example. Get a piece of paper. Put a penny (or something flat) on it. That is your flat man. He cannot see up and over anything because his world is completely flat. Draw a line on the paper. He can't see over it. It is a wall to him. You can make a box with an opening for a door and call it his house. When he is in his house, he thinke he is boxed in on all sides. But, you know different because you see in three dimensions. You know that you can pick him up and put him outside his house. The little flat man's point of view (lack of being able to see up) is similar to our point of view (inability to see forwards and backwards in time). --Kainaw ^(talk) 16:14, 11 April 2006 (UTC)[reply]

Spacetime GangofOne 23:20, 11 April 2006 (UTC)[reply]

Kainaw's example is greatly explored in the book Flatland by Edwin A. Abbott, a book I'd certainly recommend. E WS23 | (Leave me a message!) 01:10, 12 April 2006 (UTC)[reply]

Or The Planiverse for a more detailed and mind-blowing view of what life would really be like in 2D space. —Keenan Pepper 04:06, 12 April 2006 (UTC)[reply]

The allies of space and time was first perceived by the German mathematician Hermann Minkowski, when he studied his former pupil Einstein's Special Theory of Relativity and realized that their unique connection in behaviour due to the states of motion of the observed objects must be that they are ultimately one thing altogether- space- time, neither one nor the other. This idea was so radical and useful that Einstein incorporated it himself later for inclusion in General Relativity, ten years later. For a better mathematical understanding of the subject, please consult the special introductory page on the Special Relativity page and spacetime. Luthinya 18:32, 12 April 2006 (UTC)[reply]

Size exclusion chromatography - De-salting a protein solution

I am trying to desalt a protein solution using a column of Sephadex G-25. Is there a rule of thumb for how concentrated this protein solution can be? (I know that if the solution is too concentrated, it causes problems) ike9898 17:08, 11 April 2006 (UTC)[reply]

Salt concentration or protein concentration? --BluePlatypus 18:29, 11 April 2006 (UTC)[reply]

Protein concentration. ike9898 20:51, 11 April 2006 (UTC)[reply]

Well, it all depends on the flow, eluent, the protein itself, etc. But 25 mg/ml seems to be the maximum recommended[5]. --BluePlatypus 21:42, 11 April 2006 (UTC)[reply]

If you have a concentrated, salty protein solution the best desalting choice might be dialysis. Simply put the solution inside some moistened dialysis tubing and place the whole thing into a low salt buffer, which you can replenish as necessary. You can leave it overnight or longer. The dialysis membrane traps the protein inside while the tiny salt ions will diffuse through the membrane into the low salt solution by osmosis. This is a routine technique in protein prep.

Another option may be using a centrifugation based device. This allows you to desalt and concentrate the protein in a single step. Refer to the manufacturer for more details (e.g. Centricon).

Size exclusion chromatography is a good technique for purifying one protein from a mixture of proteins and is seperates based on molecular weight. As in all chromatography, the amount you load on this column depends on how big the column is. The bigger the column, the more you can load. Refer to the manufacturer's instructions for your particular brand of packing for the recommended loading amount.

I'm desalting a protease and I get autolysis if I dialyse. SEC is very quick, and easy to set up in a cold room. But, my protein peak is spreading WAY too much. I thought it might be due to too high a protein conc (increasing viscosity). This technique should be routine, but it is new to me and it's giving me a royal pain! ike9898 17:55, 12 April 2006 (UTC)[reply]

LG L1515S monitor

I use a LG LCD monitor LG L1515S. Is it a low end, low quality monitor? This is the cheapest LCD monitor which I saw and I thought it does not matter to buy the cheapest monitor? Is there any problem buying cheap LCD? whats the problem? Comparing cheapest LCDs and mid/high quality CRTs, which is better?

LCDs tend to be dim, only give a good quality pic when viewed straight on (not at an angle), and occasionally have a few pixels which are some random color. CRTs don't have these probs, but might be harmful to your eyes, can be blurry, tend to be rather heavy, and may not last as long. A plasma screen display is the best of all, but most expensive, too. You should look at the max resolution (1280x1024, for example), screen size (15 inches, for example), and the refresh rate (60Hz, for example) to evaluate a monitor. Ideally, they should all be as high as possible. Note that the refresh rate often varies with the current resolution setting. A low refresh rate will make the screen appear to flicker, especially when a white screen is displayed. A low resolution will make it difficult to display much on the screen at once and a small screen will make you need to squint to see anything. StuRat 21:50, 11 April 2006 (UTC)[reply]

Refresh rates aren't really relevant to LCD monitors. One thing that does matter with LCDs is response times: the lower, the better. If you want to play videos or games, 8 ms (milliseconds) is great, and anything under 16 ms is good. In this day and age, the benefits of LCDs generally outweigh the benefits of CRTs: in fact, most places barely sell CRT monitors any more. Sum0 15:22, 13 April 2006 (UTC)[reply]

Also with lcds you have to be quite carefull about the resoloution. Higher ≠ better Windows at least (i can't speak for linux or mac) pretty much relies on changing resoloution to change the displayed size of text (there is a font size setting but the user interfaces or lots of app break if you dare change it). Running an LCD at any resolotion other than an exact fraction of its native means a blurry display that gets very hard on the eyes.

This means several things

you must be happy with the size of things on your normal desktop at your lcds native resoloution
if you run games you must be happy with them on your screen, lukilly games tend to use much bigger text than productivity apps so the blurring isn't such an issue but it still helps if you are happy with your games at the native resoloution or a fraction therof (happy with includes both framerate and detail, normally you balance theese by adjusting resolotion but LCDs put you in something of a straightjacket).
If your vision deteriorates (or if an older relative wants to use your computer) you can't just lower the resoloution to compensate.

All in all this adds up to a lot of lost flexibility when moving from crt to lcd Plugwash 00:18, 14 April 2006 (UTC)[reply]

Call termination charge in USA

Is there call termination charge in USA? In India, telecom companies from which calls originate pay a call termination charge of Rs.0.30 to the network in which the call terminates. Is there any call termination charge in USA? If yes, what is the call temination rates? How come companies offer unlimited calling to other companies's phones when there is a termination charge which metres by the minute?

The US telecom industry places all sorts of goofy charges and surcharges on telephone calls. While our article doesn't enumerate many, the FCC has a sample phone bill complete with charges and explanations for a typical US monthly phone bill. As for termination charges specifically, I think that varies by plan. As I recall, such charges may exist but are frequently handled by a long-distance provider who then provides the end-user with a flat per-minute rate. — Lomn Talk 19:46, 11 April 2006 (UTC)[reply]

Difference between Google news & topix.net

What is the difference between topix.net and Google news? Both seem to aggregate news. But topix.net serves ads and no one minds while there has been lawsuits against Google news and it is not able to serve ads. Whats the reason and whats the difference between these two?

First, money. Google is a cash cow for lawyers to sue. Second, methodology. Google searches anyone they like and they post results of their search. News sites have to partner with Topix (see their 'about us' page for info on the types of partnerships they have). --Kainaw ^(talk) 23:58, 11 April 2006 (UTC)[reply]

A medical query?

Taking my place at the urinal this afternoon, I was joined by my newest coworker setting up shop at the adjacent recepticle. Somewhat contrary to my own restroom M.O., he asked how I was doing, and out of politeness I returned the question. However, despite the divider between the urinals (which really ought to be law), I was struck by that phenomenon commonly known as "stage fright." That is, even though I had a full bladder on (in) my hands, I was incapable of micturating until immediately after he left. Why/how does this occur?

The bladder is controlled by the autonomic nervous system. Parasympathetic neurons innervate the wall of the bladder (the detrusor muscle, trigone and sphincter). Parasympathetic stimulation results in contraction of the bladder muscle and relaxation of the urinary sphincter resulting in urination. This is opposed by the sympathetic division of the autonomic nervous system.

Anxiety or fear, including social anxiety, results in decreased parasympathetic stimulation and increased sympathetic stimulation of the bladder, resulting in relaxation of the bladder proper and tightening of the urinary sphincter, making it more difficult to pee. There's always the stall. - Nunh-huh 18:47, 11 April 2006 (UTC)[reply]

There is an article covering this: Paruresis --Ed (Edgar181) 20:34, 11 April 2006 (UTC)[reply]

I believe this is an evolutionary adaptation. That is, urinating or defecating in the presence of a stranger (or someone you don't fully trust) is a bad idea, as it leaves you vulnerable to attack. Thus, humans (and other animals) tend to delay elimination until they feel safe to do so. I suggest you use a stall, instead. StuRat 21:37, 11 April 2006 (UTC)[reply]

Indeed this phenomenon is contrary to the popular train of thought: that fright causes urination. As noted above, in humans, a sympathetic response to a stimulus will basically keep you from urinating, it is when you get to a safe place and the sympathetic stimulus stops that you will urinate (in a situation where your body decides you are safe again, although you still may be "scared") often uncontrollably. This reaction is actually a situation rather specific to humans: in canines, for example, sympathetic stimulation will usually cause urination when the bladder is anything but empty. Tuckerekcut 01:20, 12 April 2006 (UTC)[reply]

I believe in dogs, urinating on themselves is used as a sign of submission. StuRat 03:49, 12 April 2006 (UTC)[reply]

benefits of organic foods for immunno-compromised individuals...

I would like to know what the benefits are, if any, of organic foods are for immuno-compromised individuals, those with HIV/Hep C in particular. Thank you.

---BR.

I'm not sure that they are. You may want to check out our article on organic food. The crux of your question revolves around how organic foods differ from ordinary foods, which itself is the center of a firestorm of debate. However, the article does mention that organic foods grown in manure actually increase the risk of contamination with E. coli and other bacteria, which is not a benefit at all. Isopropyl 19:29, 11 April 2006 (UTC)[reply]

No body knows. No rigorous research has been done on this. Some doctors believe that there may be benfits, but it's highly controversial. For great justice. 01:23, 13 April 2006 (UTC)[reply]

There was some research in the UK last year sometime which found that there was no scientifically identifiable benefit in earing organic fruit & vegetables. AllanHainey 10:01, 13 April 2006 (UTC)[reply]

computer repair?

what is the best way to fix up an old computer?Cooliabeanias 19:26, 11 April 2006 (UTC)[reply]

Using old computers to run Linux is always a good choice. It runs well even with limited resources, and you can learn to use it on an expendable machine. Isopropyl 19:29, 11 April 2006 (UTC)[reply]

If you are technical enough to figure out what type of power supply and memory you have, you can look into getting an upgraded motherboard and CPU that will use the same power supply and memory. You'll benefit from extra CPU speed with little investment. The common mistake is to buy the motherboard first - then finding out that you need to buy a new power supply and new memory because the old stuff is incompatable. Then, the cost is so much that you could have bought a new computer. --Kainaw ^(talk) 19:53, 11 April 2006 (UTC)[reply]

Many "old" but workable computers get put out with the trash. It is possible to get quite usable parts from such machines. Power supplies, drives, cases, sound cards. Sometimes the machine works perfectly, just is old. This is a wasted opportunity, when so many people, mostly kids, could learn a lot from having such a machine. Out of date for the lastest stuff perhaps, but plenty good for learning. If you can put together such machines, you can just give them away, if nothing else. GangofOne 23:15, 11 April 2006 (UTC)[reply]

I've tried to give away old "refurbished" computers for email/web browsing. It is difficult. Beggers quickly become choosers. I set up four computers at the homeless shelter with a 5th providing a shared dial-up connection. The problem was that the shelter didn't want to provide a line for dial-up. So, they just became machines for playing solitaire (which was easier to do with the many decks of free cards laying around). Also - on a distantly related topic - I was with a professor doing a talk on Beowulf Clusters. A reporter at the conference asked if these clusters will make use of all the old computers out ther. The professor's response was memorable: "Sure, if you want a huge power hungry heat box with nearly as much processing speed as a standard home PC." --Kainaw ^(talk) 23:38, 11 April 2006 (UTC)[reply]

There are charities exporting refurbished computers to developing countries (see eg here). But I can't help wondering whether the economics of this really work, given that most new computers are manufactured closer to the people being sent the old ones ... (And the "it reuses them which is better than the environmentally-unfriendly components getting junked" argument has to be balanced against the fuel used, surely.)

The only really practical use I can think of for old boxes is as middleboxes if you're running a small LAN off a shared broadband connection or something. --Bth 10:29, 13 April 2006 (UTC)[reply]

Chemicals

how do chemicals reacted in diffrent ways when mixed together thanks alot tomas

They react in a predictable fashion depending upon their chemical properties, hope this helps.

There are several good articles where you could start looking to find what you need: chemical reaction, list of reactions or the category Category:Chemical reactions. --Ed (Edgar181) 20:30, 11 April 2006 (UTC)[reply]

Well, if there was an easy answer to that question, there wouldn't be much need for chemists, would there? :) --BluePlatypus 21:31, 11 April 2006 (UTC)[reply]

Library Classification of books

I have the responsibility of classifying our monastery library. I have been able to find a conversion of Library of Congress numbers with the Dewey Decimal numbers for an annual fee of over $300. Out of the question for such a small library. Is there a conversion table or some kind of rule of thumb that would help quicken the process? I have not been too successful wiht an internet search.--216.129.236.59 19:44, 11 April 2006 (UTC)[reply]

Is the Poor Clares Monastery in Great Falls? How large a library do you have? Does the existing library have Dewey call numbers, and you want to switch over to Library of Congress? If so, and if the library is not too large, would it be useful to use the LOC website to look up the books and obtain the LOC call number? Some of the external references in the linked articles may help. - Nunh-huh 20:18, 11 April 2006 (UTC) You may also want to consider joining the "Project:Wombat" mailing list, where a lot of librarians hang out, and ask this question there. - Nunh-huh 00:31, 12 April 2006 (UTC)[reply]

I have an old book called Dewey Decimal Classification and Relative Index - published by Forest Press Inc, Lake Placid, NY. My copy is dated 1959, so whether it's still being printed or not I have no idea. Unfortunately, given its age, it has no ISBN (ironically it has a LoC Call number - 59-11569). It is designed for libraries and provides a list of all the dewey classifications both alphabetically by subject and numerically by code. Understandably, given its age, it has certainly been considerably revised since then (where would you file books on DVD recording, OCR, or even digital watches?), but if it's still out there it might be exactly what you need. Grutness...wha? 02:36, 12 April 2006 (UTC) uhh. skip that - I misread the question. Grutness...wha? 02:42, 12 April 2006 (UTC)[reply]

I am familiar with the Forest Press book. I used it in school eons ago. I don't need a detailed list as we are going with a modified Dewey Decimal classification. And, good heavens, Nunh-huh, why would you come up with Great Falls Montana and specifically a Poor Clare Monastery at that? Isn't that a little obscure and wild? Our books are unclassified at this point. So I am starting from scratch. 12:22, 12 April 2006 (UTC)

Your IP address (216.129.236.59) is listed as being in Great Falls, MT. --Kainaw ^(talk) 13:24, 12 April 2006 (UTC)[reply]

I found this site which gives the Dewey classification if you enter the ISBN. If you can get your hands on a bar-code scanner (maybe an old CueCat somewhere?), there seem to be several free utilities around to help in creating a catalog. --LarryMac 15:09, 12 April 2006 (UTC)[reply]

Not much help for any book published before 1970, though... Shimgray | talk | 15:29, 12 April 2006 (UTC)[reply]

Speaking as a cataloguer for a small-medium library, we use DDC20 at work - it's two decades old, but as long as you're willing to be creative with some sections (we have a heading which technically parses as "21st century history of the Soviet Union"!) that's not much of a problem. Anyway, the point there is that older editions of Dewey work fine, and if you try asking around it's quite possible a larger library (or library school) still has the old cataloguing manuals gathering dust on a shelf somewhere after they went to a more modern version - they're not much use after you've changed, except for training purposes, so asking nicely might well just get them as a donation.

Of course, real classifying might be more effort than you want... if all you need is a very simple "high-level" classification, OCLC do publish a list of the "thousand sections", the top-level sections of Dewey (PDF), which should give you a baseline to be going on with. For individual books, you could try running them through the Library of Congress online catalogue - they have Dewey numbers listed for most of their stock - but it's probably just as quick to give them a general classification yourself once you have the hang of it. Shimgray | talk | 15:28, 12 April 2006 (UTC)[reply]

Thank you, for all your help. With the information provided I was able to find just what I needed. Shimgray's link to OCLC.org I was able to find the summary. Now I will be able to keep our classification consistant and heave others help me do the cataloging. We want the library to be extra user friendly and so we are using a modified DDC. I checked with all our PC monasteries on-line and culled the best possible classification system for our smaller libraries whcih ae also over loaded in the 200's. And, yes, I am at the Poor Clare Monastery in Great Falls, Nunh-huh. I would like to go back and do some adding to the Poor Ladies entry as it is bare bones information. It will have to wait a while as I have my hand full right now.Judith 20:26, 12 April 2006 (UTC)[reply]

Sounds good, and glad you got to a solution. Have a good time organizing, and we await any contributions to the Poor Clare article with patient antici-----pation! (It really is a little pitiful!) - Nunh-huh 23:34, 12 April 2006 (UTC)[reply]

I suppose it depends on how many books you have but I always prefer a more idiosyncratic filing system - largest to smallest, left to right. It makes it more fun looking for something & increases the chance of finding something you never knew you were looking for.AllanHainey 10:04, 13 April 2006 (UTC)[reply]

Gasoline and styrofoam

I've always been told that styrofoam will dissolve in gasoline and therefore you shouldn't store one in the other. Does this happen? And if so, why? Dismas|^(talk) 22:17, 11 April 2006 (UTC)[reply]

Yes, gasoline does dissolve styrofoam; I know because I once tried to fashon a funnel from a styrofoam cup, to help get gas into my moped. Gasoline is a non-polar solvent, and it is good at dissolving other non-polar materials, including stryofoam. Some synthetic polymers are much more resistant to this than others. ike9898 22:21, 11 April 2006 (UTC)[reply]

Gasoline is a good solvent. Some idiots apparently use it in the washing machine to clean grease off their clothes, and then get a nice explosion when they put the clothes in the dryer. (The clothes may not have any oil stains, but you will need to pick them out of the debris to find out.) StuRat 22:34, 11 April 2006 (UTC)[reply]

Styrofoam melts easily in any number of solvents, including gasoline, turpentine, paint thinners, etc.. It can also sometimes melt from lemon juice. Ande B 00:48, 12 April 2006 (UTC)[reply]

Dissolving styrofoam and soap in gasoline is a good cheap way to jellify it, creating a napalm. :) --

Mac Davis] ⌇☢ ญƛ. 04:29, 12 April 2006 (UTC)[reply]

Thanks for the replies, everyone. I'm sure the gasoline that those people use in their washing machines does wonders for their septic systems if they happen to be on one. :-) Dismas|^(talk) 10:29, 12 April 2006 (UTC)[reply]

Coyote/dog hybrids

I overheard a man at the pet store the other day say that his dog is half coyote. Are Dog/Coyote hybrids fertile? User:Zoe|^(talk) 23:01, 11 April 2006 (UTC)[reply]

I guess Coydog answers my question. User:Zoe|^(talk) 23:04, 11 April 2006 (UTC)[reply]

April 12

Gettin' burnt...

i accidentally burnt my finger yesterday with an iron, and little watery poxes appear on my finger, why's that? Thx --203.218.93.206 01:08, 12 April 2006 (UTC)[reply]

I'll take blisters for $400, Alex. - Nunh-huh 01:09, 12 April 2006 (UTC)[reply]

You can check out Burn (injury) as well for more information about burns. Ans e ll 01:11, 12 April 2006 (UTC)[reply]

You have a second-degree burn. (Please leave your OHIP number on my userpage.) - Cybergoth 04:22, 13 April 2006 (UTC)[reply]

Need Help on an Article

Can I get some help with checking the information on the Boiling Constants page and also setting up the data into tables? Ctifumdope 01:33, 12 April 2006 (UTC)[reply]

One comment, the Wikipedia naming convention is to only capitalize the first word in an article name, and make it singular, so you should rename the article accordingly to Boiling constant. StuRat 03:43, 12 April 2006 (UTC)[reply]

Help:Table is a good page that can help you with formatting your information into tables. -- Daverocks (talk) 04:35, 12 April 2006 (UTC)[reply]

I moved the page to List of boiling constants of solvents. --

Mac Davis] ⌇☢ ญƛ. 05:40, 12 April 2006 (UTC)[reply]

Sound and Balloons.

hi, i would like to know why and how does a exploding balloon produce sound? thankyou — Preceding unsigned comment added by 202.138.102.141 (talk • contribs)

Sound waves in air are composed of alternating pressure differences. The pressure inside a balloon is higher than outside (or it wouldn't be inflated in the first place). When you prick it, the pressure equalises; because the speed of propagation of pressure differences isn't infinite (it is, of course, the speed of sound), this doesn't happen instantaneously -- an expanding sphere of high pressure radiates out from the balloon, which you hear as a bang when it reaches your ear. --Bth 09:46, 12 April 2006 (UTC)[reply]

I was interested in this question, since the process is somewhat identical to earthquakes. Here is a good reference: [[6]] It has nothing to do with the air, but the speed of the fracture propagation, and the whip of the fragmented ends. These form mini sonic booms. You can experiment by interferring with the latex (tape) and showing how it muffles the sound. You can do different things to get a really loud pop. --Zeizmic 14:30, 12 April 2006 (UTC)[reply]

ElectroMagnetic Disturbance

How is it that a nuclear explosion creates an elecromagnetic pulse?How does this harm modern IC's only when they are in use?

See electromagnetic bomb for the processes involved and how they interfere with electronics. But where do you get the idea that ICs are only vulnerable when in use? Unless they're shielded (by being put in some sort of Faraday cage) they're going to be vulnerable on or off. --Bth 10:56, 12 April 2006 (UTC)[reply]

Computing Data Storage DVD

What is the difference between a DVD-RW DVD-R and DVD+RW DVD+r?

"R"s can be written to once, then the data's fixed; "RW"s are rewritable (with full erasure first for the -, random access for the +). The +/- thing is a standards mismatch between different manufacturers (like VHS/Betamax for video formats, except that we're still at the stage where the marketplace hasn't chosen a standard). Various arguments are advanced in favour of the two; you can read more at the articles in question. --Bth 10:45, 12 April 2006 (UTC)[reply]

Altitude and temperature

Why does it become cooler as we go higher?As we are nearing sun i suppose it should get hotter.-explain

Erm, no. For one thing, the heat from the Sun reaches the Earth as radiation, much of which passes through the atmosphere and heats up the ground, but the overall siutation is complicated --there are layers where temperature increases with altitude, but the processes involved are more involved than just "it's nearer the sun". See Earth's atmosphere for more. --Bth 10:35, 12 April 2006 (UTC)[reply]

The higher you go the thinner the atmosphere is, which means fewer particles to transfer the sun's radiation (or heat absorbed from surroundings) to you. Also with more room to move the particles are less energetic. Higher pressure = hotter. Lower pressure = cooler.--Anchoress 11:08, 12 April 2006 (UTC)[reply]

However, in the thermosphere the temperature is controlled by the absorption of solar radiation and the temperatures can get as high as 2000^oC. So there the questioner's original assumptions do sort of hold. --Bth 11:11, 12 April 2006 (UTC)[reply]

It's still entirely irrelevant that you're closer to the sun. The difference in solar radiation intensity between the ground and the top of the thermosphere (using 690km) is

9.2\times 10^{-6}

, which is hardly important. It is true that some high-energy radiation is available there for heating that isn't available on the ground, but it's more like the rest of the atmosphere is in the thermosphere's shadow, rather than that the thermosphere is appreciably physically closer to anything. --Tardis 17:11, 12 April 2006 (UTC)[reply]

Unfortunately your idea happens to be the common misconception. It is totally irrelevant here, as Tardis has said, whether you are close to the sun or not. The fact is that as you go up higher, the atmospheric pressure drops considerably, and with fewer air particles to transmit the sun's radiation or generate energy between themselves by bumping into each other, naturally the air temperature drops. I suppose your closer distance does mean that you would expect to feel the heat of its radiation more strongly, but even without the effects of the atmospheric pressure as I have described, considering the vast cosmic distances between the sun and the earth, even a mountaineer standing at the top of Everest will not be able to feel all that much difference to when he was upon sea- level itself. Luthinya 18:39, 12 April 2006 (UTC)[reply]

Vectors in EMW

Is there an easier practical illustration of the common terms we use in Electromagnetic Theory like Gradient,Curl,Divergence?

Which illustrations are you already familiar with? In general, they're slightly fiddly to get across in non-mathematical form, hence the amount of handwaving that generally goes on, but they work wonderfully once you get your head round the del operator.

Having said which, Feynman probably handles them wonderfully in Volume II of the Lectures on Physics; I'll look it up tonight when I get home. --Bth 10:40, 12 April 2006 (UTC)[reply]

In fact, Feynman pretty much takes the same delaying the physical meaning until you've grasped the maths approach that I was suggesting. Rather surprising. --Bth 10:22, 13 April 2006 (UTC)[reply]

Marine Engineering

How is it possible to maintain a watertight seal between the rotating propeller shaft and the hull in a submarine or ship keeping in mind the intense water pressures the submarine will face when submerged?

I'm sure this question's been asked before, but I can't find it ... --Bth 11:08, 12 April 2006 (UTC)[reply]

Stuffing box --Zeizmic 11:45, 12 April 2006 (UTC)[reply]

calcium / sugar

Is it oxalic acid, made from calcium?, that the body uses to digest sugar?? not sure if i spelling right.

Oxalic acid is two COOH groups bolted onto each other; it contains no calcium. Enzymes are what break foods down in digestion -- for the specifics of the digestion of sugar, see glycolysis and for what happens after that, Krebs cycle. Calcium is important in the body as a constituent of bones and teeth. --Bth 12:48, 12 April 2006 (UTC)[reply]

As a note Calcium is involved in Muscle contraction and is involved in carrying the eletrical charge down a Neuron in the Electrical synapse. Wish I had better sources for the neuron thing as it's been 9 years since my animal physiology course.--Tollwutig 13:30, 12 April 2006 (UTC)[reply]

Oxaloacetic acid is an intermediate in the breakdown of most sugars, yes. Neuronal transmission is mostly the affair of sodium and potassium. Physchim62 (talk) 13:41, 12 April 2006 (UTC)[reply]

Though calcium is involved in transmission across chemical synapses, by triggering the release of neurotransmitter vesicles. I'm guessing calcium has only a small role in typical electrical synapses because the intracellular concentration of calcium is so low in most cells. --David Iberri (talk) 22:03, 12 April 2006 (UTC)[reply]

And, yet, if the concentration of calcium ions in the extracellular fluid drops, it produces excessive and painful muscle contractions called hypocalcemic tetany. The concentration may be low, but Ca is certainly not unimportant to neurmuscular transmission. alteripse 00:43, 13 April 2006 (UTC)[reply]

MIME

Can you please explain what a "MIME TYPE" is?and can you list a few MIME types?

We have a good article on MIME. MIME helps identify what the type of content that is being sent is. Some examples are: text/plain, text/html, image/jpg (I think). -- Daverocks (talk) 12:42, 12 April 2006 (UTC)[reply]

IIRC the last one should be image/jpeg. --cesarb 19:18, 12 April 2006 (UTC)[reply]

Time series analysis

The linear regression model can be used to estimate expected value. When applied to a time series, linear regression may not be useful because it is time-neutral. If I have a scatter chart of a time series, what kind of statistics tool should I use, if I want to:

Estimate a rope's possibility of breaking over time. The rope is under a significant load, the fibers of the rope could break any minute. So the strength of the rope may suddently decrease over time. To estimate the possibility of breaking at t₀, we may forget about past values. Let's say we have a lab and 1000 such ropes and loads.

Estimate a rich person's tendency to buy gifts over time. Suppose the man is influenced by his ever-changing mood. If he's very happy, he can be buying gifts all the time. We don't know if he's happy at any given moment, but we can increase the weight of t₀±Δ to emphasize the influence of his mood.

Estimate a person's tendency to invest over time. Suppose all that person has is a stock ticker. At the time of decision making, he/she only has past performance. -- Toytoy 12:40, 12 April 2006 (UTC)[reply]

Did you come up with those examples yourself? 'Cos they sound awfully like homework ... --Bth 13:02, 12 April 2006 (UTC)[reply]

Yes, that's homework. And I am my own teacher. @#$% I should have taken some statistics while I was in college but I did not. -- Toytoy 13:13, 12 April 2006 (UTC)[reply]

I'm not sure how a linear regression is relevant here. In the rope example, it sounds like you're trying to statistically describe the lifetimes of ropes under stress. That's just one-dimensional data: a vector of times. You'd just be using standard things like mean, variance, and [[skewness|]] to analyze that. The other two examples don't have a clear goal to me... if you have data like "on December 11, Roger bought 2 gifts" and "on December 12, Roger bought 0 gifts", all you can usefully do is find times that seem interesting and posit that important events happened then. If you additionally had "on the evening of December 11, Roger's pet mouse caught the flu", then you might want to compute some sort of correlation between the two sets of data. With appropriate quantification of everything and some luck, you might be able to come up with a reasonable model (

d^{2}{\mbox{gifts}}/dt^{2}=k({\mbox{good news density}})

or something), and then you could do predictions of one variable (gifts or good news) from the other. But when, say, you were trying to calibrate

k

, you'll just want to use regular statistics, since your model exists outside of time and does not need to be causal. If you do do past-only analysis, it's typically as simple as truncating your data to whatever point in time, fitting some sort of curve to it in the usual ways, then extrapolating beyond it. --Tardis 17:24, 12 April 2006 (UTC)[reply]

A problem about Live Linux CD.

Hi, just recently i got a softwares dvd, in which Tablix Live Linux CD's ".iso" file was supposed to be there. but actually it was a ".rar" file. so i extracted the whole "rar" file, and then "burned" all the extracted files onto a CD. i am using windowsXP. then i tried to run "tablix" from that cd by making default boot from cd drive, but it didnt work. after that i ran the cd on winXP, even then it didnt start, actually a ".html" file about "tablix" from the cd did start on autorunning, but the OS wouldnt start. now how to do it? even on their website they have not mentioned how to install and use it for windows user. Similarly, on the same DVD, there is an "image" of Cluster Knoppix, but when i see that file's properties, it doesnt show it to be an "iso" file. i tried to burn that knoppix image on to a cd, by using nero 7, but it showed the message that unrecongnisable format, and so i didnt go further. so wats all this going on ? i am a windows user, and if a normal user like me has to go through so much hassles for just trying Linux, is it serving good to the open source community? not at all. so could you please recommend some Live CD OS which can work directly without such hassles. Also , can u tell me any website or organisation , which could send me these Live Linux CD's or other free Linux CD stuff to me. i am from india, and internet speed at my home is not too great, and also too expensive for me to download the ".iso" files of around 600mb size. so if u could recommend some sites which would do so and send me the CD's in india at my place? thank you.

If you have WinRAR installed on Windows, it makes itself the default application to open ".iso" files. This could possibly be why you think it's a rar file, because WinRAR likes to open iso images. If you're right, though, and the images are really ".rar" files, it would probably be better to put all the extracted files into an iso of its own, rather than burning all the files manually. Also, when you say you tried to run Tablix and it "didn't work", does that mean that Windows started booting and the CD didn't? More details would be appreciated. Also, if you tried to get Nero 7 to burn an image file and it said "unrecognisable format", then what you're trying to burn definitely isn't an ISO. What format is that image in? -- Daverocks (talk) 12:51, 12 April 2006 (UTC)[reply]

More generally, you could try Linux India (that's the WP article, this is their site) or one of their affilliated LUGs (Linux User Groups) for help getting started with Linux -- it seems to be a large part of their mission to help newbies. And if you don't manage to solve your problems, apparently thanks to LI's activities, sites like this one now sell distros on cheap CD to India. --Bth 13:01, 12 April 2006 (UTC)[reply]

I think Ubuntu linux will still mail you free cd's. They send a live CD and an installation CD. And your problems seem to have to do with the configuration of your Windows system, not the linux distrobutions themselves. But I agree getting in touch with the local linux groups would be good, as you'll have lots of things that will be much easier if you have someone to help you with. - Taxman ^Talk 17:48, 12 April 2006 (UTC)[reply]

Have you set your bios to boot from cd? For great justice. 01:15, 13 April 2006 (UTC)[reply]

He noted that "i tried to run "tablix" from that cd by making default boot from cd drive". Still, maybe he didn't try to set the order through BIOS. -- Daverocks (talk) 04:02, 13 April 2006 (UTC)[reply]

Why are adults less able than children to tolerate dizziness?

Most kids could spin in circles for a minute or more with only mild nausea that quickly passes. Many or most adults would feel ill to the point of vomiting from such motion, and are probably more likely to get nauseous from a simple thing like swinging. Why are children generally better able to handle getting dizzy? --Jonathan Kovaciny 12:49, 12 April 2006 (UTC)[reply]

Your assumption does not sound correct to me. People that are highly active can handle motion better than people who rarely move. Children spin, tumble, and run around more than adults. So, a higher percentage of children have a tolerance for that action. Adults who continue to spin, tumble, and run around maintain the tolerance. Also, children who spend all their time sitting in front of the tv do not have a tolerance for motion. --Kainaw ^(talk) 13:11, 12 April 2006 (UTC)[reply]

Need to buy a 'surge protector'

1:24 PM 4/12/2006 DST Need to buy a 'surge protector'

Hi all, I need to buy a 'surge protector' or I think an 'automatic voltage stabilizer' for my home computer as power cuts are becoming more

frequent. The budget is low and i don't think I need anything as fancy as a Uninterruptible Power Supply; just a Plain Old stabilizer is sufficient? I

don't know much about the impact of a hot boot on the devices in my Willamette processor or the 1.5 GHz board. All I know is there might be some

damage to the hard disk with repeated incidents of power failures. Is there anything I am missing? Thanks for your care and dedication. I have been reading this page for quite some time now and I CTRL+D ed it on my firefox. Yours truly, -- Kushal one 17:38, 12 April 2006 (UTC)[reply]

A surge protector is no use at all in a power cut. It is designed to protect against sudden increases in power ("surges"). In a power cut, the computer switches off, unless you have an Uninterruptible Power Supply. Notinasnaid 18:34, 12 April 2006 (UTC)[reply]

Don't know what a stabilizer is, but you need some form of Uninterruptible power supply --Zeizmic 19:55, 12 April 2006 (UTC)[reply]

A UPS can act as a stabilizer, in that it will maintain a steady voltage in the event of power sags or power surges. A surge protector alone might help in eliminating any surge that occurs as power is restored after a power cut. --205.143.37.68 21:25, 12 April 2006 (UTC)[reply]

I think there is a difference between a 'surge' protector and a 'spike' protector. I am not sure if that is relevant to what is being discussed here, but here goes what I think is the difference. A 'surge' protector is for things like electric motors which will overheat if too much current is pushed through them, often they have circuit breakers to protect against that. A 'spike' protector protects against brief overvoltages which often occur when powerlines are near a lightning strike, these are very hard on electronics and can cause progrsssive failure because each spike does some damage to the components.

Yes. If you are living somewhere with frequent power cuts, you likely have spikes and surges too. Get a UPS. If you can't afford one, a surge protector will help reduce damage from too much electricity, but won't help with not enough. For great justice. 01:08, 13 April 2006 (UTC)[reply]

The colour of water

I recall reading once a upon a time that the colour white corresponds to the highest frequency point on the Sun's black body curve (somewhere around 6000K). This is not coincidence, but an evolutionary adaptation. Rather than saying "sunlight is white at its brightest" it is probably more accurate to say "our manner of perceiving white has been conditioned by the sun." An animal around a red dwarf might perceive our red as white and our white perhaps might be invisible in the manner of x-rays etc. OK, if that's utterly out to lunch somebody tell me.

So this got me thinking about water the other day. Again, it's obviously not coincidence that our main biotic solvent happens to be transparent. Would it be fair to say "our manner of perceiving transparency has been conditioned by water"? Another hypothetical alien basking in liquid ammonia might view H2O as an opaque poison? Any formula that describes this sort of thing? I suppose the evolutionary mechanism would be "the clearer the water the safer the drinking." Marskell 17:50, 12 April 2006 (UTC)[reply]

As I understand (part of) your question, you are asking if, given different conditions during our evolution, we could ahve evolved in a way that water was not transparent to us, but something else (that is opaque to us) might be transparent to these alterative people. Water is transparent becuase it absorbs little radiation from the 'visible' portion of the spectrum. The radiation absorbed by water wouldn't change, but we could have evolved so that our eyes were attuned to a different part of the spectrum. I believe water is fairly opaque in the UV, so if our eyes saw UV, water would indeed be opaque as well. As to whether there is some solvent that is opaque in the visible but transparent on UV or infrared, there probably is, msaybe someone could provide an example? Chapuisat 18:41, 12 April 2006 (UTC)[reply]

"the colour white corresponds to the highest frequency point on the Sun's black body curve", better to say, not highest frequency, but rather , most abundant. Which is maybe what you mean. Yes, it is natural that we are sensitive to the light frequencies that are most copious in penetrating the atmosphere. To be otherwise would be a missed opportunity. But it doesn't apply to transparency. What is transparent to light is physically determined couldn't be changed subjectively in the viewer. Anyway, why would it matter if water where opaque? What if water were silvery like mercury, why would that matter? Except for minor adjustments, like not diving into water without testing depth etc? I don't see why life couldn't evolve if that where the case. (Water in the eyes, would be a problem; probably a workaround) GangofOne 23:08, 12 April 2006 (UTC)[reply]

Transparency could be changed if we are talking about seeing with a radically different spectrum of "visible light". For example, if infrared was all we could see, we would perceive some things as being transparent which are not transparent to the radiation we call "visible light", and we would perceive some things as opaque which are currently transparent. Transparency is not quite the same sort of thing as color perception but it is not radically far off. But the "color of water" bit is misleading in this regard, I think. --Fastfission 00:02, 13 April 2006 (UTC)[reply]

"Highest" --> "most abundant", yes thank-you, that was poor word choice. So you're saying it is essentially coincidence ("couldn't be subjectively changed in the viewer")? As for why it would matter, I would guess that opacity would be something of a handicap to early marine creatures. Perhaps a transparent solvent is not required for evolution, but it certainly doesn't hurt once you develop eyes. Marskell 08:06, 13 April 2006 (UTC)[reply]

Of course the light we get from the sun is ALSO in the range of energy transitions of many chemical reactions, (many chemical reactions for chemicals our living world is made of, because it evolved under those conditions. note the circularity...) EG photosynthesis rxns, etc. Here is where in the intelligent design advocates can speculate. If the sun gave off microwaves, say, than a planet to form life would have to have a mwave transparent atmosphere, chemistry of life as we know it would be impossible, would have to be different chemistry. etc. Many techincal problems. And if you try to track down solutions, it may be that eventually all alternate scenarios won't work. Then ID might say, constants of physcics are such that nuclear rxns in the sun are such that the radiation it gives off are such that on a particular type of planet with certain gaseous atomosphere at certain temperature could form life rxns that make life possible and allow life to see and cognized that the constants of physics are such that .... (It all fits together) I mean the IDists COULD make such a claim, if they were smart enough. --GangofOne 19:40, 13 April 2006 (UTC)[reply]

A problem about GIMP

Hi, just recently i downloaded GIMP (latest version) from sourceforge.net, and all the help files and also animation package along with the necessary GTK. it was working fine on my laptop, but when i tried to install it on my personal computer, running winXP, during installation it said that some files were already present , so it gave me option of "renaming" them. but i decided not to rename them. so it got installed with no problem.but now whenever i try to run it, a msg appears that "an error has occured and GIMP will shut down". this error just wouldnt go. i re-installed it several times, but it didnt work, now what should i do? GIMP is great , but these problems just make open source a headache. could u help me?

Why is this an open source problem? As for Gimp, did you remove it first before reinstalling it? --Kainaw ^(talk) 18:38, 12 April 2006 (UTC)[reply]

yes i did uninstall it before installing it.

For more specific help here, you'll need to be a bit more specific about the errors during installation, and whether you get the same errors each time. Also, have you tried that project's help forum? --Tardis 20:15, 12 April 2006 (UTC)[reply]

Skew Universe

What exactly are the implications of a skew universe, and what are the possiblities that we may live in one ourselves? Luthinya 18:41, 12 April 2006 (UTC)[reply]

You'll have to give a rigorous definition of "skew universe" first. It doesn't seem to be a well-established scientific term. Perhaps you'd be interested in brane cosmology? Also, skew in other fields is typically a relative description; it means nothing if you only consider one object. If that's the case here, then the question "do we live in a skew universe?" is meaningless, and the "implications of a skew universe" are null. Now, if we somehow found another universe and it was skew to ours... --Tardis 20:34, 12 April 2006 (UTC)[reply]

I think this is a follow up to the question about the perpendicular universe theory that was asked a while back--172.129.106.218 00:10, 13 April 2006 (UTC)[reply]

Unless its the same person, I think he is just asking about parallel universes. Check it out. --

Mac Davis] ⌇☢ ญƛ. 01:18, 13 April 2006 (UTC)[reply]

I know which section you were talking about vaguely, since I myself have seen it, but I am NOT the same person- since I am obviously female- and as far as I know my problem does not concern parallel universes directly, which I had taken a considerable interest in a few months earlier. My question arose from an article of a scientific journal- whose name I can't recall- discussing the various possibilities of different "models" of the universe arising from modern physics. The article only contained a brief sentence concerning the skew universe so I decided to ask here to satisfy my curiosity. I have had a vague idea now- I've checked for the word skew in a mathematics article and obtained the relevant information. LCS 08:32, 13 April 2006 (UTC)[reply]

radiology

What is the flow of electrons in an x-ray tube?

See X-ray; in particular, the history section. --Tardis 20:47, 12 April 2006 (UTC)[reply]

cells

Why do lysosomes function best in acidic environments?

Maybe you should look up lysosome? I'm sure that has the answer to your homework question. --Tardis 20:56, 12 April 2006 (UTC)[reply]

This isn't sufficiently answered on Lysosome. --David Iberri (talk) 21:17, 12 April 2006 (UTC)[reply]

(After an edit conflict, and noting that this didn't immediately strike me as a homework question...)

It's really the digestive enzymes within the lysosomes that function better in acidic environments. Each of these enzymes (like all enzymes) is a protein whose ability to function is dependent on its ability to assume the proper shape. If the enzyme is in the wrong shape, it won't be able to act efficiently on its substrate. For lysosomal enzymes, having the wrong shape means not being able to perform enzymatic digestion optimally. A protein's shape is governed by its tertiary structure, which is maintained in large part by hydrogen bonds between the protein's amino acids. And hydrogen bonds are exquisitely sensitive to pH. Change the pH enough and the hydrogen bonds will be disrupted, forcing the protein to assume an improper shape (called denaturation) and therefore become less active.

This provides some measure of protection to the cell. Consider a case in which the lysosome bursts, spilling digestive enzymes into the cytoplasm. The higher pH (less acid) of the cytoplasm would render the lysosomal enzymes less active, protecting the cell from digesting itself. Hope that helps, David Iberri (talk) 21:17, 12 April 2006 (UTC)[reply]

I thought it was -- it mentioned the pH-dependence of the digestive enzymes, and the bit about their being somewhat disabled if a lysosome leaked. But the denaturation details you gave are nice. I didn't even ask the question, but thanks. --Tardis 15:37, 13 April 2006 (UTC)[reply]

Relativity and the speed of light

My friend posed the following scenario to me earlier: Assume that you have a highly efficient solar sail attached to a ship, and that you set the ship and sail in motion in space. Assuming the ship does not pass near enough to any highly massive objects to greatly affect its speed, and that it receives a steady supply of solar energy, will the ship ever exceed or match the speed of light?

I say no. Mass increase tells us that, even given a steady source of energy, the ship's mass would increase without bound as its velocity increases, and the ship would require infinite energy to meet the speed of light.

However, my friend tells me that, given Newton's F=MA, sufficient energy would allow the sail and ship to meet and exceed the speed of light.

I am quite confident of my own thoughts on the matter. However, I would like concrete mathematical or physical evidence to show my friend the error of his ways.

--Doubleplusungood 22:46, 12 April 2006 (UTC)[reply]

You're entirely correct; in fact, it requires an infinite energy (and hence infinite time) to accelerate an object with non-0 mass to c , which will, of course, never happen. The kinetic energy of the spacecratft would be

E_{k}=mc^{2}({\frac {1}{\sqrt {1-(v/c)^{2}}}}-1)\!

(see Kinetic_energy#In_relativistic_mechanics). As v approaches c, this number approaches infinity. Recommend a good book on relativity to your friend. --Borbrav 00:26, 13 April 2006 (UTC)[reply]

He's kind of right - sufficient energy will accelerate the ship to the speed of light. It's just that sufficient energy doesn't exist in the universe... For great justice. 01:05, 13 April 2006 (UTC)[reply]

As for concrete physical evidence, particle accelerators verify relativity all the time. You can accelerate a charged particle with changing electric fields, and as it gets closer to the speed of light, its energy grows (and therefore it acts heavier) without limit. No matter how long you keep accelerating it, it will never reach or exceed the speed of light. —Keenan Pepper 08:15, 13 April 2006 (UTC)[reply]

Hello! This is doubleplusungood again, with a few additional questions. My aforementioned friend is with me now. Here are his thoughts: 1. In the solar sail example, assume the universe is composed only of a single star and the sail device. The star is thus emitting radiation that continues constantly to hit the sail. The constant addition of energy will never reduce. Due to the absence of gravity (negligible gravity, that is), the sail will never slow down of its own right, and the continual input of energy will continue to accelerate the sail, due to conservation of energy. 2. Since light is affected by gravity (e.g. black holes), and can also be slowed down (by gravity and refraction through everyday objects, like water or diamond). Since Newton declared that only mass is affected by gravity, light must therefore have mass. In accordance with relativity, light thus cannot attain the speed of light. What is the speed of light (as light can slow down), and what is light, since it must have mass and cannot travel at a velocity of "c"? --Doubleplusungood 17:44, 13 April 2006 (UTC)[reply]

There's a very simple explanation you're overlooking: Newton was wrong. Massless particles are affected by gravity. Chuck 20:40, 13 April 2006 (UTC)[reply]

There are two types of particles: those with a rest mass and those without. Those with a rest mass cannot be accelerated to c, regardless of energy input, per above. Those without rest mass (e.g. photons) can only move at the speed of light, and have a "mass" that is related to the energy they carry. --Borbrav 22:10, 13 April 2006 (UTC)[reply]

Excretion and body temperature

Is it possible to lower one's body temperature by urinating or defecating? The answer is probably a resounding no, but I want to know for sure. Bhumiya (said/done) 22:47, 12 April 2006 (UTC)[reply]

No. Poop and pee are the same temperature as the human body as long as they're in the human body. So there's no chilling or warming effect by getting rid of either of them. - Nunh-huh 23:30, 12 April 2006 (UTC)[reply]

Not by urinating or defecation but by eating and drinking it is possible because all of that food/water has to be heated. Just look at the energy balance. Assume you take in all food and water at room temp. (25 C) for one day. Assume it comes out of your body at 98.6 F (37 C). Then, 12 C or 12 K is the difference. Now find the specific heat of the composition of urine, probably around water, which is about 4.18 J/(g*C). Approximate urine as water again and at 1 g urine / 1 mL urine

..then for every 1 mL of water you consume at room temp you're burning 50 J which is .012 food Calories (kcal). I think this is negligible. Even if you drank 10 liters of water a day that'd only be 120 Calories of heat exiting your body. That's nothing.

Because I don't have an approximation of the specific heat of feces I don't know how much energy it takes to heat it, but you can bet that based on our water approximation that the energy spent to heat up the food you take in is nothing compared to the Calories in the food (or even if the food has no Calories it would still be so small as to be negligible).

So no, I don't think it's physically possible to intake so much food and water as to decrease your body temp.

-Snpoj 02:13, 13 April 2006 (UTC)[reply]

As a liquid, urine will evaporate, so the truly desperate might try urinating on themselves in order to take advantage of the enthalpy of vaporization. Isopropyl 08:24, 13 April 2006 (UTC)[reply]

April 13

Perfect Secrecy in a Cryptographic System

According to Claude Shannon's paper, perfect secrecy is obtained when |P|=|C|=|K|. Is it admissable to have |C|=|P|<|K|? i.e. if I have a cipher where Pr(y|x) = Pr(x) does the size of the key matter as long as it isn't smaller than the C or P space? This is all assuming that the keys are equally possible and unique. Any help would be greatfully appreciated, C.Meyers

Have a read of one-time pad, and consider what would happen if any part of the key longer then the plaintext is simply discarded by both sender and receiver. --Robert Merkel 07:08, 13 April 2006 (UTC)[reply]

The statement that I have in my lecture notes from the crypto module I took a year ago says that perfect secrecy exists iff

|K|\geq |C|\geq |P|

, where K, C, and P are the sets of all keys, ciphertexts, and plaintexts, respectively (and |X| is the cardinality of set X.) This is slightly different from the relation you've given, where all three sets have to be the same size. -- AJR | Talk 12:29, 13 April 2006 (UTC)[reply]

Cheese!

I assume individually packaged cheese slices solved two problems:

1. consumer demand for pre-cut cheese (i.e. not having to cut out a slice from a big block, just like sliced/unsliced bread)

2. consumer demand for cheese with a longer expiration date. Individually wrapped cheese will last much longer than cheese in a block which supposedly goes bad after about 5 days because once you open it, you've opened an manufactured air-tight seal.

Question: is assumption 2 correct? (how bout 1?)

-Snpoj 02:25, 13 April 2006 (UTC)[reply]

1 makes sense, 2 less so. Many of the best types of cheese last a lot longer than a few days (though pre-processed ones may not, of course). In fact, many types of cheese are far better after they've matured for a considerable length of time. Grutness...wha? 03:57, 13 April 2006 (UTC)[reply]

Assumption 2 is incorrect. My friend (who's worked with cheese professionally) tells me that cheese is pretty much good until it molds, and even then those parts can just be cut off. Also, if exposure to air was a problem, then you would want to reduce the surface area exposed. Isopropyl 08:21, 13 April 2006 (UTC)[reply]

I'll chime in with a bit of a note on this. While cheese that is exposed to air doesn't go bad itself, it will dry out. For softer cheeses with higher moisture content, this definitely affects the texture and the quality of the eating experience.

A minor caveat to the 'just cut off the moldy bits' approach—mold and toxic mold secretory products can travel a short distance into the cheese beyond the extent of visible contamination. Again, this is more of a concern in soft, moist cheeses. The bold are still welcome to cut off the mold and enjoy; just remember that you may want to cut a bit of a margin around the mold.

Finally, individually wrapped cheese slices do let you avoid the mold problem altogether. Presumably, a person will only open a slice with the intent to eat it (nearly) immediately; there is no time for mold spores to settle and grow. In a sense, I'd say that assumption 2 holds because people want to avoid the perception that their cheese has gone bad, whether or not it is still safe to eat.

The major problem with the processed, prepackaged, hermetically-sealed cheese slices is that – in my entirely subjective opinion – they don't taste very good. They're also only available in a limited number of flavors. TenOfAllTrades(talk) 12:37, 13 April 2006 (UTC)[reply]

A good cheese will last months, though its appearance will get worse and it might frighten some people. Consider (3) it allows people who don't trust their small children with knives to still have them make a cheese sandwich (4) it provides a controlled and measured amount of cheese, rather than a rather random personal slice (5) it is easier to snack on the pack outside the kitchen. Notinasnaid 09:10, 13 April 2006 (UTC)[reply]

cgi script code demands unix?

I looked at a cgi script and it's got '$mailprog = '/usr/lib/sendmail -i -t';' in it. Does that mean it can't be used on a Windows based server? Can you get unix emulators for windows like you can get Wine for unix/linux...? --Username132 (talk) 05:02, 13 April 2006 (UTC)[reply]

Don't know about the first question but I think this is a popular linux emulator for Windows -Snpoj 05:06, 13 April 2006 (UTC)[reply]

I don't think there is a version of sendmail compiled for Windows. You could try Cygwin, as Snpoj said, but I don't find that to be entirely reliable, especially if you would be planning to use it for server purposes. -- Daverocks (talk) 06:39, 13 April 2006 (UTC)[reply]

You could rewrite the script so that it uses a mail service on Windows instead (you'd have to check what mail service is available, there is no one standard). Notinasnaid 09:07, 13 April 2006 (UTC)[reply]

PC monitors on TV

Why does a monitor on TV (like in the news) have weird bands going down it over and over? --Username132 (talk) 05:24, 13 April 2006 (UTC)[reply]

Cathode ray tubes create pictures by scanning from top to bottom. So if you point a television camera at a CRT screen, each frame [29.97 per second in NTSC, 25 per second in PAL] will see the screen at a different part in the cycle, and a different part of the screen will look bright. -- Filliam H Muffman 06:01, 13 April 2006 (UTC)[reply]

Can't ping 127.0.0.1

I run Mandriva Linux version 2006.0 and I've struggled with this problem for quite a while, namely that I can't ping 127.0.0.1 (local loopback), nor can anything make a connection to it. I can use ping to ping everything else (e.g. yahoo.com, wikipedia.org), so ping is not the problem. This is what happens when I try to ping 127.0.0.1:

[root@davidlaptop ~]# ping 127.0.0.1
connect: No buffer space available

Configuration of the loopback interface is fine:

[root@davidlaptop ~]# ifconfig lo
lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:9279 errors:0 dropped:0 overruns:0 frame:0
          TX packets:9279 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:524961 (512.6 KiB)  TX bytes:524961 (512.6 KiB)

Some people have asked me about my /etc/hosts file, but this is also normal:

[root@davidlaptop ~]# cat /etc/hosts
127.0.0.1               davidlaptop localhost

Now here is the strangest part. After bootup, I am able to ping 127.0.0.1 with no problem. However, after about 5-10 minutes, pinging 127.0.0.1 suddenly stops working, again yielding the message "no buffer space available". And although most of the time I am unable to ping 127.0.0.1, sometimes it suddenly starts working for seemingly no reason. Usually it stops working after this as soon as I stop being active on the Internet (my Internet is through interface wlan0). This problem is extremely frustrating as it causes me to be unable to test my Apache server, my FTP server or use Tor at all. Does anyone have any idea why it might be happening? I can provide more details on request. -- Daverocks (talk) 07:02, 13 April 2006 (UTC)[reply]

These links are the closest that I could find to a solution, although there is no confirmation that the solution worked for all involved. [7] Another link is [8] they have an even longer explanation and it says solved, but I am not sure that the problem is the same. Ans e ll 07:54, 13 April 2006 (UTC)[reply]

Thanks, those links are quite helpful, more relevant than the ones I was able to find. Particularly the first one you provided had helpful information. I'm still not sure what's going on, and I still haven't "definitely" solved the problem. However, something seems to be happening when I disable the lisa service and stop cupsd. Thanks for your input. -- Daverocks (talk) 01:44, 14 April 2006 (UTC)[reply]

Black Holes and Gravity

If Black Holes may possess a gravitational field so great that even light cannot escape it (except under exceptional circumstances such as Quantum tunnelling), then is it implausible to assume that a same type of mass-energy may be generated within the universe that will really allow superluminal velocities? I know that the square root within the transformations of Special Relativity turns imaginary when the velocity exceeds the speed of light, and thus explained away as making no sense, but considering the implications again of a Black Hole- if the gravitational field may be generated so great that even the photon cannot escape it, then this field, being a curvature in spacetime caused by mass-energy of some sort, must similarly lead to the possiblility of an energy level capable of exceeding the speed of light. In that case, maybe the imaginary square root may be taken to mean something even more esoteric. Or is something still missing from the story? All help appreciated. LCS 08:44, 13 April 2006 (UTC)[reply]

is it implausible to assume that a same type of mass-energy may be generated within the universe that will really allow superluminal velocities?

Yes, for a mass to reach superluminal velocity, than that would require a kinetic energy as being infinity. How unlikely. Gravity and electromagnetism are separate forces. --

Mac Davis] ⌇☢ ญƛ. 10:11, 13 April 2006 (UTC)[reply]

See tachyon. There's no evidence for them. —Keenan Pepper 11:06, 13 April 2006 (UTC)[reply]

java

I sort of know that java is a program [to help you?] but do you need it on your computor? I get more updates to install on my M/C than I do from Microsoft and it's very persistant to get me to install them I have XP with service pack 2 installed 60.229.175.88 09:12, 13 April 2006 (UTC)[reply]

It is useful if you want to see Java Applets on webpages, or if you want to run Java based programs on your computer. The Java download here [9] enables this. Ans e ll 09:32, 13 April 2006 (UTC)[reply]

Java is often used to show you part of a web page. You probably have it already. Bear in mind that Microsoft offer you updates because you already have an older version of the software and if they are security fixes it may be very important to install them. Notinasnaid 09:33, 13 April 2006 (UTC)[reply]

Never ever accept Microsoft Updates. You'll just be putting a lot of hard-working hackers out of business. Please, someone, think of all the poor hackers. --Kainaw ^(talk) 12:02, 13 April 2006 (UTC)[reply]

snake

My daughter wants to know from which part of snake's body its eggs come out ? Not the process of mating or reproduction but somthing like from where exactly the baby comes out.

Thanks

At the risk of stating the obvious, the vagina. (Google produces some fascinating results, but you may not want your daughter to see them). Henry ^Flower 09:34, 13 April 2006 (UTC)[reply]

The Snake article has a reproduction section that doesn't exactly entail where the eggs come out, however, it does explain a bit about some snakes which do not lay eggs, rather keeping them inside them and/or giving birth to live young. I assume the position that they lay eggs from would be about 2/3rds of the way down the body, however I can't seem to find any sources for that right now. Ans e ll 09:40, 13 April 2006 (UTC)[reply]

This page claims a video, which I have not watched: http://www.arkive.org/species/ARK/reptiles/Coronella_austriaca/more_moving_images.html. Notinasnaid 09:49, 13 April 2006 (UTC)[reply]

You can't see the whole body of the snake in the video, so it's hard to judge, but I'd say it's about 3/4 of the way down. On the bottom, of course. Interestingly our vagina article mentions that the vagina leads to the cloaca 'in some reptiles', but doesn't say which reptiles. Henry ^Flower 09:59, 13 April 2006 (UTC)[reply]

The same question was asked and better answered at "Ask A Scientist" - Zoology Archive - Snake Delivery - 1/19/2004:

"most snakes lay eggs (oviparous) some of them deliver a baby, outside the eggshell ready to live (viviparous). The reproductive system of the reptiles including the snakes are simpler than the one of the mamals and resembles the birds. There are both in males and females an opening to the exterior called "cloaca". The cloaca is the passage from a internal chamber into which the digestive, urinary and reproductive systems empty. So both the baby snake or the non-hatched egg go to the exterior through the cloaca. Incidentaly, inside the female snake body there is a tract called oviduct provided with conditions for egg fertilization and embryo formation." [10] WAS 4.250 11:32, 13 April 2006 (UTC)[reply]

The human brain

I’ve was told that researches were made about our brain’s function that found that when we see things and when we imagine things, the brain uses the same parts. Meaning that our brain cannot differ between what it sees to what it remembers/imagines. Can you please guide me to those researches? Thank you

There was an article all about this in the February/March Scientific American Mind pages 18-23. Called "Picture This." by Thomas Grueter. It refrences:

Image and Brain: The Resolution of the Imagery Debate. Stephen M. Kosslyn. MIT Press. 1996.

Return of the Mental Image: Are There Really Pictures in the Brain? Zenon Pylyshyn in Trends in Cognitive Sciences Vol. 7. No. 3, pages 113-118; 2003.

If you can't find it on the internet, I can scan in the article for you without any trouble. See my talk page User_talk:Mac_Davis. Here is a search for zenon pylyshyn cognitive [11].

--  Mac Davis] ⌇☢ ญƛ. 10:22, 13 April 2006 (UTC)[reply]

A myth or a true story?

I was told that the Indians couldn’t see Columbus’s ships arriving because they didn’t have that image in the image bank in their brain. Is it a myth or a true story?

Hahahahah! It is a myth. Just because you haven't seen anything before doesn't mean you can't see it! How do you think you see things that you haven't seen before? --

Mac Davis] ⌇☢ ญƛ. 10:13, 13 April 2006 (UTC)[reply]

It's true. I kept telling 16 year old girls that I cannot see their nakedness because I do not have that image in the image bank in my brain and so if they take off all their clothes then all I can see is a blank spot where their nakedness is. Ohanian 10:33, 13 April 2006 (UTC)[reply]

I heard that story. I believe it was from a documentary on Amerigo Vespucci. In his novel about the New World, the native women were beautiful, big breasted, and extremely dumb. The men were stupid and lazy and handed over tons of gold and silver to the white men to have sex with their women for them. His story was, obviously, not written from real accounts. --Kainaw ^(talk) 12:00, 13 April 2006 (UTC)[reply]

Definitely a myth. This story has been spread a bit by the movie What The Bleep Do We Know!?, a "documentary" which is not at all scientifically accurate. rspeer / ɹəədsɹ 15:35, 13 April 2006 (UTC)[reply]

I believe "What the BLeep" got the idea from some anthropologist's writing. I am trying to track down whose. Any body know? I KNOW this story was out there before that movie came along. Plus, the movie explains it badly and exaggeratedly. --GangofOne 19:06, 13 April 2006 (UTC)[reply]

I'm not entirely sure about the truthfulness of What the bleep do we know, but a similar thing I heard about when going through the topic of evolution comes to mind, I'll try to retell the story briefly:

An explorer went to live with a jungle-dwelling people, who obviously had never left the jungle, he befriended them and decided to take one of their people to his world. On their way to a city, they crossed a savanna, the short jungle-dweller (being short is a nifty adaptation for jungle life) spotted a couple of grazing animals in the distance, he recognized them as flies, and tried to wave them away with his hand.

The reason for this is that the jungle-dwelling man had never ever seen anything so far away, and his concept of distance was limited to perhaps five metres away at most, as jungles don't really have that much open space. In a sense, he could not possibly imagine something that big being visible from that distance, and could thus not know that things look smaller with distance. -Obli (Talk)^? 21:38, 13 April 2006 (UTC)[reply]

I'd be suspicious of that one too. Most stories about the silly things "savages" do are false at best and insidious at worst. --Fastfission 01:36, 14 April 2006 (UTC)[reply]

Computer Network Tockin Ring

Dear All,

I have some confussion related to Computer Networking below theories/terminology, If anyone can clear me below points. than I highly be thankfull.

01: Why saying? "Token Ring" is Local Area Network Technology
02: Why "Token Ring" is not inlist in Channel Access Methods?
03: Please tell me difference between "Network technology, Access Method and Network Protocol"

Thanks.

M.Sadiq Qadri [enough with the personal info]

Why do you care whether a "token ring" is a LAN or not. As long as it's implemented correctly it will work. The only time, I care about the definition of "token ring" is when I need to hand in my computer science assignment at University. Ohanian 10:29, 13 April 2006 (UTC)[reply]

Token ring is it's own access method. Think about it, terminals can *only* speak when they have the token. The Token Ring article does quite a good job at describing it. --Jmeden2000 13:16, 13 April 2006 (UTC)[reply]

Token Ring is a LAN technology, it just uses a different structure for determining which system is transmitting data. In fact modern Token Ring systems use the same physical infrastructure as Ethernet. The reason Token Ring is not commonly used is 1) Originally IBM propriatary technology. 2) More expensive due to 1. You may want to look up Local Area Network, Token Ring. If you want more detailed information on Networking I would suggest you by a used copy (new is $65+) of a Comptia Network+ exam. As these guides cover the basics of Networking and a lot of the terminology of Networking.--Tollwutig 15:00, 13 April 2006 (UTC)[reply]

Fundamental forces, "weak charge"

Electromagnetism is the coupling of photons to electric charge. Gravity is the coupling of hypothetical gravitons to all energy. The strong force is the coupling of gluons to color charge. The weak force the coupling of W and Z bosons to... what? My physics book mentions "weak charge", but doesn't go into any detail and doesn't say what kinds of particles have it. I notice we don't have an article on it either. Is there really such a thing as "weak charge"? —Keenan Pepper 11:21, 13 April 2006 (UTC)[reply]

No fundamental weak charge exists. "Originally, weak interactions were thought to be separate from electromagnetic forces. Eventually, three fairly massive particles were discovered: W+, W-, Z. The weak force is an electromagnetic interaction producing one of these particles. The particle travels then is absorbed through electromagnetic interactions with another particle. Although the Z-particle has no electric charge, it does have a spin. It can interact with magnetic force. Standard electromagnetic force is transmitted by photons of light. Weak force is transmitted by these "weak" particles. Still the actual interactions are the based on the same force." [12] WAS 4.250 11:47, 13 April 2006 (UTC)[reply]

All leptons and quarks with left-handed chirality are susceptible to the weak force. Notably, as a result it's the only force to affect neutrinos, and the only force that can cause flavour changing processes (thus it's responsible for beta decay, though note that the Z boson cannot cause flavour changing -- there are no flavour changing neutral currents). See weak interaction for lots more. But as per WAS's quote there isn't an identifiable "weak charge" as such. --Bth 12:00, 13 April 2006 (UTC)[reply]

See Weak hypercharge. I'm guessing that that corresponds to the weak coupling constant, or maybe it's weak isospin. Cedders 00:30, 14 April 2006 (UTC)[reply]

Well, I still don't understand it, so I guess I'll just have to wait until I take... Particle physics? Quantum field theory? What? —Keenan Pepper 01:04, 14 April 2006 (UTC)[reply]

CDMA 2000

Qualcomm says CDMA 2000 provides an always-on Internet connection. What does it mean and how does it work? How is always-on different from other type, that is not always one in previous cell phone technologies?

I presume it means it is always connected, like broadband, rather than only connected when you connect it, like dial-up. For great justice. 15:40, 13 April 2006 (UTC)[reply]

Cross border complexities related to the IT industry in India

What cultural bias exists towards western economic philosophies as thsy relate to the IT and Software industry in India?

Did the homework question also misspell the word they? hydnjo talk 14:56, 13 April 2006 (UTC)[reply]

The instructions above for answering questions specifically states to be nice. Spelling flames and assumptions about the origin of the question (without even answering the question) isn't very nice. As to the question, googling '"western economic philosophy" india software' got nothing, but '"western economic" india outsourcing' got lots of interesting hits, including:

and lots of others. I didn't find anything on Wikipedia, but maybe someone else will.--Anchoress 21:24, 13 April 2006 (UTC)[reply]

Width of the United States

How many miles wide is the United States? I could not find this statistic in United States nor Geography of the United States. Thanks. -- Reinyday, 17:35, 13 April 2006 (UTC)

This question is not very well-defined. First we must specify what portion of the Earth we designate as "the United States". But it's not very interesting to say that the US is typified by the distance between Hawaii and Maine, as that's certainly not representative. So let's suppose you mean the contiguous United States. Obviously even that is not a rectangle (even disregarding the curvature of the Earth), and so does not have a single "width" or "height". But presuming that by "width" we mean "east-west extent", we can talk about the lengths of various lines of latitude running through the country (these will be of many different lengths). As a very rough approximation, using the Extreme points of the United States article, I see Lubec, Maine at 66°59′5″ W, and Cape Alava at 124°43′59″ W. They're not at the same latitude -- about 3° different -- but it's close. The portion of the latitude line midway between theirs (about 46°25′ N) between their longitude lines is (using the quadratic mean radius of

Q_{r}=3,959.871{\mbox{ mi}}

)

Q_{r}\cos(46^{\circ }25')(124^{\circ }43'59''-66^{\circ }59'5'')=2751.5{\mbox{ mi.}}

A similar expression using San Diego, California and Miami, Florida (though they are 7° apart in latitude, so this is a poorer approximation) gives 2237.4 mi. The best one can really say from these figures is that the "width of the US" is

2500\pm 250{\mbox{ mi}}

. (Remember that these are not great-circle distances; the shortest route from (40°N,90°W) to (40°N,80°W) is not to go due east. But the differences at these latitudes are on the order of a percent or so; the errors in averaging the latitudes are larger.) --Tardis 18:20, 13 April 2006 (UTC)[reply]

If you define the US in terms of effective control, we control land and water all across the globe, and indeed into space. If you define US as legal sovereign teritory by law, our embasseys are technically our sovereign territory, and again we are global. If you define US as States and territories we entend from at least Maine to Guam and probably further, but I'm not gonna look up every island the UN assigns us control over. The distance of the two points in Alaska that are furthest from each other is interesting and similar to Canada and Russia useless distances. It is all about definition. Something to ponder: When you find the right way to ask a question, the question is the answer to itself. WAS 4.250 20:43, 13 April 2006 (UTC)[reply]

Or you could go from Hawaii to Florida, or Hawaii to Alaska, or Florida to Alaska for even longer distances. --

Mac Davis] ⌇☢ ญƛ. 23:58, 13 April 2006 (UTC)[reply]

Protiens and Sugars

Where might I find a list of the important protiens and sugars that build the human body? Specifically, something that will help me in understanding how humans decompose at teh chemical level. 64.198.112.210 20:20, 13 April 2006 (UTC)[reply]

List of proteins WAS 4.250 20:30, 13 April 2006 (UTC)[reply]

A list of proteins and sugars won't give you what you need. Try decomposition, though it's not too detailed, it may get you started. There was a book called something like Corpse that discussed this, too, but I can't quite think of the exact title. - Nunh-huh 20:57, 13 April 2006 (UTC)[reply]

Bomb defusal

I was watching a certain movie over the weekend, and it contained a scene where a bomb is being defused Hollywood-style: a guy with wirecutters clipping the red wire. Does this have any factual basis? Is there a history of bombs being defused in this fashion? Isopropyl 22:50, 13 April 2006 (UTC)[reply]

It's the correct way to defuse a Hollywood-style bomb: one with a half-dozen sticks of dynamite wired to an alarm clock. Our bomb disposal article covers how real-world bombs are taken care of. --Serie 23:55, 13 April 2006 (UTC)[reply]

I don't know, but I'd like to add a similar question. What is the big, red LED readout for on such Hollywood-style bombs? Is it there for the convenience of those who just may be standing by the bomb, so they'll know when they'll be blown up? If so, that's very considerate of the bomb designer, don't you think? Erik the Rude 23:20, 13 April 2006 (UTC)[reply]

Unless it's a trap; #15. Melchoir 00:06, 14 April 2006 (UTC)[reply]

April 14

Ramjet

I was wondering if anyone could give me a few really nice links on how to build Ramjets? Patrick Kreidt

Ramjet --

Mac Davis] ⌇☢ ญƛ. 00:58, 14 April 2006 (UTC)[reply]

Dermatographic urticaria

Is this disorder genetically inherited? --218.102.207.71 00:55, 14 April 2006 (UTC)[reply]

Combining CC-BY-SA

I wanted to combine a CC-BY-SA 2.0 and CC-BY-SA-2.5 image. Is there any changes between the two licenses that would make this impossible? I assume this is doable, but I wanted to make sure, as not to create a copyright violation. Thanks in advance, Linuxerist L/T 01:14, 14 April 2006 (UTC)[reply]

Darn search engines

What is the name of the theory that the act of observing changes the behaviour of the subject being observed? -- Francs2000 01:27, 14 April 2006 (UTC)[reply]

I think this is what you mean: Uncertainty_principle but according to that page "The uncertainty principle is frequently, but incorrectly, confused with the "observer effect", wherein the observation of an event changes the event. The observer effect is an important effect in many fields, from electronics to psychology and social science.". Not sure if I completely agree with that statement but there you have it. -Snpoj 01:46, 14 April 2006 (UTC)[reply]