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September 2

Self CPR

I'm taking a final exam for an online class and one of the questions I have to answer is whether self CPR is fact or fiction.

Perhaps you could think about this for a few seconds. BenC7 01:58, 2 September 2006 (UTC)

If you are unconcious how would you do it?--Light current 02:03, 2 September 2006 (UTC)

There is a procedure to help yourself when you are choking where you hold your fists just south of your thorax and run into a wall with your head held back (I Canada you usually learn that as an aside on your way to becoming a life-guard). Maybe something similar could work for when your heart stops, though I think the chance of your heart stopping and you knowing while being concious are pretty much zero. Then there's the fact that manual CPR usually only works after repeated applications, which means you'd be running into the wall a lot.  freshofftheufoΓΛĿЌ  06:27, 2 September 2006 (UTC)

...That is a procedure in Canada? Can I PLEASE see it on tape or something? If I didn't suspect it would hurt like a bum, I'd try it out. Sounds difficult to run onto things like that. Henning 08:26, 2 September 2006 (UTC)

Haha, I've never actually seen it done. My instructor just explained how it could be done if you were ever caught by yourself with a chicken bone stuck in your throat.  freshofftheufoΓΛĿЌ  15:57, 2 September 2006 (UTC)

Fiction. If you have no pulse and no respirations, you are unconscious and unable to do CPR. InvictaHOG 09:32, 2 September 2006 (UTC)

Which leads me to think, are you sure it's "self CPR" and not "self Heimlich-maneuver" or something? Just a thought. CptJoker 01:22, 3 September 2006 (UTC)

5 or 10 years ago there was a story which made the rounds of print media and internet that if one suddenly realized his heart had stopped, he could do self cpr by coughing vigorously, and get enough blood to circulate to maintain consciousness long enough to summon help or dial 911. A while letaer Red Crosss officials denied it was true. Could one realize the heart had stopped and still have consciousness for a bit? Why not? Edison 20:31, 2 September 2006 (UTC)

That's not to be done if your heart stops, it's taught in MedSchool if you go into VF. If you cough, at least some blood gets moved around cos the valves keep doin' what they're doin' despite zero cardiac output from ventricles. ≈Eh-Steve 21:02, 2 September 2006 (UTC)

Viral Marketing

I'm rather worried by the note at the bottom of the Factotum article. I wandered through the history, and apparently on 3 August, an anonymous person added what looked like a full-page advertisement for the film. On 23 August, another anonymous person removed it, leaving a rather cryptic note with a link to the viral marketing article. To be honest, I've been wondering for awhile just how much people could potentially take advantage of Wikipedia for monetary gain. Does it sound to you like that's what was happening? Black Carrot 02:16, 2 September 2006 (UTC)

Yes, it's absolutely a problem with a medium like Wikipedia. A simple example would be all the neologisms that people try to get added, thus increasing awareness about the unknown word in the hopes that somebody will actually get tricked into using it in an AOL chat session. Most of those get caught pretty easily, but I imagine it's much more difficult to pick things like that out of articles with corporate connections so who knows how much if it actually gets through.  freshofftheufoΓΛĿЌ  06:33, 2 September 2006 (UTC)

When was redial invented?

I've been searching all over the Internet and I can't find the date that redial was invented. What I really want to know is, would telephones in 1990 have automatic redial buttons, and, if not, what would they have? Please help. 88.105.159.129 10:12, 2 September 2006 (UTC)

I would guess that was available on the first touch-tone phones. Dial phones did not normally have that feature. StuRat 10:24, 2 September 2006 (UTC)

True, but they had a line to the operator, who could probably redial for you--71.247.243.173 13:44, 2 September 2006 (UTC)

That would be a serious pain in the neck in comparison with just a simple button. --Fastfission 15:46, 2 September 2006 (UTC)

Ah, so it's been around since the sixties then. Thank you! 88.105.159.129 10:36, 2 September 2006 (UTC)

They've definitely been around since 1990. I can remember them from the even the very old (and crummy) phones from that time. --Fastfission 15:46, 2 September 2006 (UTC)

I have seen rotary phones with a redial function before. It's almost rediculously complex, and it seemed to take a while to actually dial the number (it of course has to mechanically spin the dial). I can't say when it was actually invented though, or if the touch-tone version came first.  freshofftheufoΓΛĿЌ  15:55, 2 September 2006 (UTC)

Yea, I see no reason why it wouldn't be possible on a rotary phone, but it does seem like an ugly bit of machinery would have been required, making it easier to just manually redial. An analog audio tape of the clicks could also be recorded then played back. A hybrid would also have been briefly possible, where the clicks were captured digitally and played back electronically. Of course, once that technology was available, why not just upgrade to a touch-tone phone, instead ? StuRat 22:13, 2 September 2006 (UTC)

Have you ever tried redial on a dual-function phone? The kind with a tone switch, that can send rotary style signals if tone-dial doesn't work in your area (or at least I assume that's why). If it's set on rotary mode, and you hit redial, you can hear it clicking away old-skool, though I've never been interested enough to figure out how it was doing it (I've had at least 1 phone from the 80s with that capability). There's actually a manual rotary redialer featured in The Matrix. Guess they never thought of using an analog recording either.  freshofftheufoΓΛĿЌ  10:22, 3 September 2006 (UTC)

You can't just tape record the sound of the clicks. Pulse dialing phones operate by momentarily opening the telephone circuit, blocking all current. The click you hear is just a side-effect of that (and, in fact, the dial has contacts that entirely or mostly mute the receiver while the dial is "off normal" (turned away from the normal position). And yes, some electronic dial-pulse phones did have "redial" capability. I had one that I'd guess dated from ca. 1980 or '85.

And then there were the card-dialing phones. Very odd, these devices (which dated from the '60s) contained a cute little card reader. By punching holes in plastic cards, you could program each card to contain one phone number. Then, by popping a person's card into the reader and pressing a single button, the phone read the card and dial-pulsed out the number, giving you the 1960s equivalent of speed-dial.

Atlant 01:15, 7 September 2006 (UTC)

Karl von Goebel

Why is Karl von Goebel sometimes known as Karl Ritter von Goebel and others as Karl Immanuel Eberhard von Goebel ? — Dunc|☺ 11:02, 2 September 2006 (UTC)

Check out Ritter. It is a title of nobility that can be added or not according to the author's preferences. Same goes for Karl von Goebel vs Karl Immanuel Eberhard von Goebel; it depends on context, space, and preferences. George W. Bush is sometimes referred to as George Bush or George Walker Bush or Dubya and Brian Eno is sometimes referred to as Brian Peter George St. Jean le Baptiste de la Salle Eno :). ---Sluzzelin 11:34, 2 September 2006 (UTC)

refrigerator vs. environment

Can a refrigerator operate successfully in an unheated garage in winter where the temperature falls below freezing?

• Why not? Don't most firdges have an internal thermostat? in which case, it would read the temperature as below 0^oC and woudln't need to do anything (: 71.247.243.173 13:43, 2 September 2006 (UTC)

• if contents of a refrigerator spoil when power is cut off when the environment is warm ...obviously the fridge is not 100% insulated....therefore, if the fridge senses the outside temp. as freezing and doesn't do anything...wouldnt the contents eventually freeze? I am referring to a fridge...not a freezer.

There's no such thing as below zero ;). My guess would be that unless you had a fridge which had the ability to warm, then prolonged exposure to below zero would cause the contents to freeze. Hell, my fridge freezes everything in sight, and it has never seen temps below zero! --liquidGhoul 14:04, 2 September 2006 (UTC)

It gets colder than -20 C in the winter where I'm from, and the answer is a pretty obvious yes, if you go away on a ski trip for a few days and turn off all the power, all of the food in your fridge will freeze.  freshofftheufoΓΛĿЌ  15:51, 2 September 2006 (UTC)

Soft drink machines are commonly outdoors in states where it gets to -20 F in the winter. I expect they have internal heaters to keep the contents from freezing. In an ordinary refrigerator, in an unheated garage, if the air got below 32 F for an extended perion the contents would certainly freeze. A little ingenuity could install an auxiliary thermostat inside to turn on the light bulb or a light bulb when the temperature in the fridge got down to 32 f. The deadband would have to be precise, so the light/heater would go off at a temperature below the one where the cooling unit went on, and contrariwise. For instance, the cooler goes on at a rise to 40 degrees and off at a drop to 37 degrees. The light bulb or heater goes on at a drop to 33 degrees and off at a rise to 35 degrees. See the problem? You could wind up with the heater on fighting the cooler. Edison 20:39, 2 September 2006 (UTC)

I expect they have internal heaters to keep the contents from freezing.

They do.

Atlant 01:03, 7 September 2006 (UTC)

If you had a small electric space heater, with a thermostat that goes down to freezing, you could put that in the fridge when it gets cold. Do they sell such heaters to keep pipes from freezing ? StuRat 22:00, 2 September 2006 (UTC)

I actually asked this question a few months ago. My suspicion, though I may be wrong, is that you guys may be off on the wrong track. From what I understand, refrigeration (as well as A/C) works by sucking in ambient air and passing it over coils of compressed freon. The freon coils are kept at a certain temperature (depending on the level at which the freon is compressed, the more compression, the colder). For a freezer, say, the freon is compressed to a point where it is below freezing, and air is then passed over them, causing below freezing temperature air to pass into the freezer, and thus causing the temperature of the air in the freezer to be below freezing temperature. For above freezing temperature refrigeration, the freon is less compressed, to a point where it is, say 1°C or 2°C. Ambient air is then blown over the coils, and the fridge temperature is lowered to just above freezing. NOW, when the temperature of the ambient air dips below freezing, the same thing happens. The below freezing temperature ambient air is sucked into the unit, blown over slightly above freezing temperature freon coils (1°C or 2°C), and thus, in a weird sort of way, the freezing ambient air is "heated up" to above freezing. I know it sounds weird, but when you think about it it makes sense. Heat doesn't always equal "fire" or "warmth" as we understand it. Think of it this way, throw a regular block of ice into a vat of liquid oxygen, and the ice cube will actually raise the temperature of the liquid oxygen. Throw a big enough block freezing cold ice in, and you may actually be able to heat up the liquid oxygen to its "boiling point" at which point it'll "boil" into oxygen gas. Of course, this is just one big guess, I could be wrong. Loomis 20:43, 3 September 2006 (UTC)

Seminar report

We have a weekly semianr to be given on any of the technological advancement aorund us. I have decided to give a seminar on the RADAR JAMMERS.

I was looking forward for some good materials so as to produce a good report. I have found a few but would like to get into the core of the subject for self interest.

Would be looking forward for help from any of u.. Thanks Saket--220.227.48.17 13:36, 2 September 2006 (UTC)

Doesn't it make sense for you to choose to give a seminar about something on which you are knowledgable, rather than just relying on the nice people at Wikipedia? —Daniel (‽)

electronic attack. Xcomradex 15:30, 2 September 2006 (UTC)

Memory Metal for Cars?

How strong are memory metals? Could you theoretically build the outside of a car from one, and then, after an accident heat it up and have it regain its former shape?

Thanks, —Daniel (‽) 14:43, 2 September 2006 (UTC)

I know this but I cant remember! I need to shape up I know 8-)--Light current 15:51, 2 September 2006 (UTC)

I don't understand why it's so expensive to replace a car body panel. They should be dirt cheap, as they're stamped by the thousand. Perhaps we need a change in the structure of auto sales, where the car company leases cars for a few months at a time. Then, when they get a dented car back, they would have an incentive to replace the body panel cheaply, so it could be released. At present, they don't seem to have any incentive to make repairs inexpensive, as that just prevents people from buying new cars. StuRat 21:53, 2 September 2006 (UTC)

A great question! BenC7 04:09, 3 September 2006 (UTC)

The price could have someting to do with labour intensity. The panel seems expensive compared to the car, but it's really the cars that are dirt cheap for the sort of product you get, due to mass production. Repair work isn't mass production, so it's relatively expensive. Maybe if you could buy the panel and then replace it yourself. But then there would have to be a distribution network for loose parts, and the per piece price would probably far exceed the production cost. Your solution would solve the latter problem, but not the former. DirkvdM 05:59, 3 September 2006 (UTC)

The existing distribution channels for dealer parts could also be used for car body panels. Each dealer could stock several of each body panel for each car model. StuRat 11:47, 3 September 2006 (UTC)

There is also the possibility of plastic car exteriors, which I believe would be easier to 'de-dent' and would also be lighter and therefore more fuel efficient. This already exists, but my guess it isn't popular because plastic can't be made as shiny as metal. DirkvdM 06:01, 3 September 2006 (UTC)

Although (at least for most cars) it's not the metal that's doing the shining, it's the half centimeter coat of crap on top of it that does. You may be partly right, though, that it seems to be more difficult to "buff" plastics smooth, which could cause problems before you coat them with the shiny stuff.  freshofftheufoΓΛĿЌ  10:14, 3 September 2006 (UTC)

Plastic body panels are actually significantly more expensive than sheet metal. They have the advantage of being lighter, but aren't strong enough for a unibody design, requiring a frame. The tend to crack when damaged, not dent, which makes them more difficult to repair. For these reasons, they tend to only be used on expensive sports cars, like the Chevrolet Corvette. StuRat 11:42, 3 September 2006 (UTC)

Special relativity

So, I've been reading into Photon, Special Relativity and more, and I have come to be frustrated, very at that, at not understanding the topic.

I realize very well that there is a particle-wave duality to photons, it's their speed I can't understand. If I travel on a pimped up spacecraft with neon lights all over, and overtake another spacecraft, I will measure the speed of HIS light as C, even though I am travelling at +V away from him and his light?

Oh, and I have a second question, way better! Is there any book like... Relativity/Quantum dynamics For Dummies, which actually explains everything? Everything with a capital E, that is polarization, QED, string theory, t... everything? Many thanks in advance. 81.93.102.35 14:59, 2 September 2006 (UTC)

(I am not qualified to answer, don't get annoyed at me) As far as I know, you are right. Whatever speed you are traveling towards/away from each other, you will still see the speed of light in a vacuum at the same. This, I think, arises from some weird curvature of spacetime. —Daniel (‽) 15:22, 2 September 2006 (UTC)

THe way I tend to think of it is that light can only travel at one speed (in vacuum). THis speed cannot be changed as it is a function of the fundamental properties of space. So, whenever you try to measure the speed, you always get the same answer. What you will see, however, is a red shift if you are travelling away from the light source and a blue shift if travelling towards it. Is this helpful?--Light current 15:40, 2 September 2006 (UTC)

Though the "...for Dummies" franchise doesn't seem to have given it a shot yet, this google search might help you find the same sort of introductions.  freshofftheufoΓΛĿЌ  15:48, 2 September 2006 (UTC)

List of ...for Dummies books does mention Einstein for Dummies! Until you get the book you can also try more googling, the first hit looks like something I'm going to go and read right now. Weregerbil 16:07, 2 September 2006 (UTC)

For future reference: Most of the parameters in a Google URL are unnecessary (and possibly undesirable for a user whose cookie has unusual preferences); all you really need is the "q=". Weregerbil gets it right. —Tamfang 18:26, 2 September 2006 (UTC)

Yes, I noticed that and I was wondering what effect the "firefox" parameter generated from my browser would have on non-firefox users. I was just being lazy anyways, I'll make my links shorter in future!  freshofftheufoΓΛĿЌ  10:09, 3 September 2006 (UTC)

The Road to Reality by Roger Penrose is your best bet for a book that explains everything. Light current's comment that the speed of light cannot change might not be entirely accurate. There is evidence that the speed of light was lower in the past.

'Moving' source, 'stationary' observer

Look at it this way. Assume you are 'stationary', and something is receding from you shining its light at you. When the light on the distant object leaves the lamp, the light doesnt know that the lamp is travelling backwards at high velocity. All it knows is that it has been launched into space and is therfore compelled to travel at the universal velocity 'c'. When you measure its spedd you find its 'c' also. Any clearer?--Light current 15:49, 2 September 2006 (UTC)

'Stationary' source, 'moving' observer

Essentially the same as above. THe source transmits the light at 'c'. Although you are moving backwards at high velocity, the light doesnt know this and doesnt care. When it reaches you, red shifted, you still measure its velocity as 'c'--Light current 16:16, 2 September 2006 (UTC)

An easier answer (or so I hope)

Ok, you're watching another spaceship full of neon lights and you're observing it's light. You're travelling away from the other ship with a velocity of V or something of the like, something pretty fast. The other ship will fall behind you pretty fast. But if you phone the guys in the ship, they'll tell you: "We aren't moving, it's you that's going away." Well, that's just a different point of view, you see? Nothing special. Velocities just seem to be different when you're moving.

Except the one of light. The guys in the other space ship aren't moving (or so they think), so when they observe their neon lamps, they'll see light coming out with a velocity of c. When you are observing this same light being in the other ship, you'll see the same velocity relative to your own position. That may seem weird – you'd think it should be c+V or c-V or something of the like. But it doesn't work that way.

To relate your observation with their observation, you need Lorentz transformation. This means that space and time are related to each other in a way which is slightly more complicated than how you'd think they are. Velocity being space divided by time, it gets quite more complicated than c+V. But the result is just c.

Hopefully this helps. David 16:42, 2 September 2006 (UTC)

But surely the Lorenz transformation is a consequence of the invariance of the speed of light, and not the other way round? So the answer should be able to be given without bringing in Lorenz? 8-|--Light current 17:55, 2 September 2006 (UTC)

Thank you for clearing this up for me. I am in the process of reading that -- for Dummies-thing, it should work wonders. :) 81.93.102.35 18:10, 2 September 2006 (UTC)

Good page: Velocity_addition_formula--Light current 18:11, 2 September 2006 (UTC)

I know that according to the Michaelson/Morely experiment, there isn't any detectable change of speed of light in any direction, so there is no basis for an ether to exist. Still, have anyone tried accelerating something in vacuum? I don't know how realistic it is to assume that this can make any difference - I just wondered if it is certain that nothing spends more time or energy accelerating into one direction than into another. 81.93.102.35 19:27, 2 September 2006 (UTC)

Try The Elegant Universe by Brian Green. It starts with a humorous discussion of classical physics including relativity and progresses through quantum and finally string theory. He does not use any math so its a good book for light reading

129.174.194.48 18:01, 6 September 2006 (UTC)

Infinitly improbable events in infinite time

In an infinate amount of time, the probability of any event happening which has a probability not equal to zero is 1. So in infinite time every event even with a miniscule probability of say the inverse of a googel to the power of a googel, will definitely happen.

So even after I'm dead, by random chance something resembling my brain with the same thoughts and memories as I have now must eventually come into existence, not only once but many times. And I could also have the same kind of body, the same kind of society even. In other words I (and you) should be resaurected (sp?) many times, if the universe lasts an infinite length of time.

Can anyone point out a logical flaw in the above argument please? For example, will the universe last an infinite amount of time?

The universe (as we know it Jim) will not last an infinite time.--Light current 17:57, 2 September 2006 (UTC)

Although assuming our universe could last for an infinate time, i don't see any flaws in your argument. Benbread 17:58, 2 September 2006 (UTC)

In case anyone hasn't seen it: Kolmogorov's zero-one law. Melchoir 18:03, 2 September 2006 (UTC)

Many events (as humans perceive them) that do occur do not simply have miniscule probablity, they actually have probability of exactly 0. If the probability of an event is 0, then even given infinite time, then you might still observe that it happens never, only once, or many times. Consider a dart board and a dart. The dart board has some finite area. The dart has a much smaller, but still finite cross-section; however one can think about the center point of the dart: some mathematical point that defines the true center of where the dart strikes. Such a point has no area, being just a point. Throw the dart at the board and you know that some point will be selected in this way, but there are an infinite number of choices and each time you select only one center point of the dart. Hence the probability of selecting any particular point is 1/infinity which is exactly equal to 0. And yet you can perform the action and know each time with certainty that some point will be selected. Further, an event with a probability of 1/infinity, given an infinite number of trials, need not be expected to occur, because infinities come in different degrees, countable and uncountable. By definition any repetitive action performed an infinite number of times belong to the countable class of inifinities because you can enumerate each trial (1, 2, 3, 4, etc.). However, it can be proven that you could never enumerate all the points on a dart board, no matter how clever your scheme might be, there are simply vastly more than could ever be described by the set of all numbers 1, 2, 3... This is non-intuitive, I know, but in many situations there are simply more possible outcomes then one could possibly precisely enumerate, even given infinite time to do so. I supsect that most of what occurs, from the effects of a single storm to the evolution of the human race, are like throwing darts at a board. A particular event occurs from an infinitely rich set of possibly variation, but each possibility had an intrinsic probability of zero. If that is the case, then the probability of you, me, or the human race ever having occurred is zero and even given infinite time should not be expected to recur. Dragons flight 18:37, 2 September 2006 (UTC)

Dragons flight chose his words carefully, I want to point it out. If that is the case, then the probability of you, me, or the human race ever having occurred is zero and even given infinite time should not be expected to recur. That's, of course, not to say that it couldn't recur, just it isn't expected. Probabilities become very hard to understand intuitively when the number of trials is infinite. So, for any event with probability zero, it could happen any finite number of times in an infinite number of trials. With respect to your question if you assign the event that someone again has exactly the same thoughts as you a positive (non-zero) probability, then the probability it occurs again given an infinite number of trials, is 1.(*) However, if such an event has probability 0, given an infinite number of trials it might happen again, but it need not. (*: This is so long as each individual trial is independent) --best, kevin [kzollman][talk] 20:51, 2 September 2006 (UTC)

It is probably theoretically possible for something to have, say 1/4 probability of ever happening given infinite time (if I have this right). Imagine that, starting now, for some x amount of time, an event has a 1/5 probability of happening within that time. After that x amount of time, then for the next x amount of time, it has a 1/25 probability of happening. Then it has a 1/125 chance, then 1/625, etc. This goes on infinitely. The sum of all those is not one (or infinity) but 1/4 (see geometric series - scroll down that page) - not one or zero.

(I know the numbers don't sum up that way - the 1/25 ends up being 1/25 of the remaining slice, not 1/25 of the total slice - but explaining all that would detract too much from the point.) —AySz88\^-^ 18:58, 2 September 2006 (UTC)

You have to remember that not all possible paths lead to all possible outcomes, when sonthings happens in the universe, it always cuts out the possibility of a an infinite number of alternative possibilities from ever happening. So basically, if the human race became extinct tomorrow, even if the universe existed for eternity, the possibility of someone exactly the same as you having the same thoughts as you is 0. Philc _T^E_C^I 19:32, 2 September 2006 (UTC)

Schroedinger's cat?--Light current 20:19, 2 September 2006 (UTC)

I'm afraid I don't see how this is related. --best, kevin [kzollman][talk] 20:51, 2 September 2006 (UTC)

As a bit of nit-picking, there is no such thing as "infinitely improbable" in the standard real number system. Something either has probability 0 or a positive probability. In order to have "infinitely improbable" one must introduce infinitesimals which results in a different theory of probability than is standardly used. --best, kevin [kzollman][talk] 20:51, 2 September 2006 (UTC)

See Infinite_monkey_theorem for an example of a finite, but highly improbable, event that would occur, given an infinite number of trials. StuRat 21:33, 2 September 2006 (UTC)

What do you think we're doing here?9-)--Light current 21:36, 2 September 2006 (UTC)

Except that we're not nearly as intelligent as the monkeys. :-) StuRat 21:42, 2 September 2006 (UTC)

Yeah, they got it made eating bananas, screwing round all day.... Hey hang on a minute- sounds familiar!--Light current 23:33, 2 September 2006 (UTC)

The formation of life on Earth may be similar. That is, it may be a highly improbably event, but, given all the planets and moons around all the stars, in all the galaxies in the universe, even highly improbable events become quite likely, somewhere. Then the not-too-bright say "but what was the chance it would have happened on the planet where we live ?". Well, the chance that life had evolved on any planet where life currently exists is actually quite good. StuRat 21:42, 2 September 2006 (UTC)

The flaw in the argument is that Kolmogorov et al are applying ideas from Pure Maths to Applied Maths (and then to Real Life). Things tending to particular limits as other things tend to infinity only means something in some very specific Pure Maths situations - to apply these processes to Applied Maths which is talking about real life is silly. Thats the flaw.

And since we're talking about real life I can postulate that the monkeys instead produce an infinite amount of garbage, or the atoms will come to resemble a donkey's thing, and you can't point to any real life cause which will necessitate that they do otherwise. Rentwa 22:31, 2 September 2006 (UTC)

What is zero multiplied by infinity? If you can do this, you have the answer.--Light current 22:35, 2 September 2006 (UTC)

Not defined by arithmetic, zero if calculated according to limits. Rentwa 22:40, 2 September 2006 (UTC)

It could be anything, calculated according to limits. For instance, lim(x->0) x(1/x)=1, x(2/x)=2, x²(1/x)=inf etc. If I may, though, I see some things that don't make sense to me. First, what does it mean to say that an event, like someone with a particular genetic code being born perhaps, has a particular "probability"? Or sentient life springing up, or whatever. The universe, above the quantum level, is as predetermined as clockwork. It's not a matter of manipulating random variables to get the answer, it's a matter of manipulating very very definite equations of physical motion. For instance, let's say we find the "probability" of a 2kg mass being pushed with 1N of force for 1s, but inexplicably gaining several thousand m/s of velocity. This would have a probability zero. Hitting a theoretical point with a theoretical dart has a probability "almost zero", meaning it could conceivably happen but almost certainly won't any time soon, but this just plain won't happen, ever. Am I right? So, it's not a question of whether a universe filled with random static could ever clear up for a moment into a universe with human life, it's a question of whether this universe, given its starting conditions and laws, will ever do so. Which it probably won't ever again, if the heat death theory is to be believed. The only thing that brings randomness into it is Schrodinger's cat, as someone earlier said, which is a demonstration of the link between the alleged pure randomness of the quantum world and normal events. Even given that, though, I doubt the question changes much.

BTW, something that crossed my mind, rereading the original question - If someone with your thoughts and memories were to show up later, given the strong link between thoughts and the reality that made them, that would suggest that the entire universe was on some sort of periodic cycle, wouldn't it? If the same things happened again, they would surely lead to the same results again, and therefore back to themselves again, ad infinitum. Only a universe where cause and effect weren't so closely linked, as in the imaginary random universe you're working with, could that not be the case. Black Carrot 23:15, 2 September 2006 (UTC)

Given multiplication of m by n is defined as adding n lots of m, 0 times infinity is the sum 0 + 0 +...+ 0 = 0 as the number of 0's tends to infinity, and it's trivial to prove lim = 0.

I've no idea what you're talking about :) . But you write very nicely. :) Very cool red sig btw. Rentwa 23:35, 2 September 2006 (UTC)

Are you familiar with the idea of a limit? Basically, it says that given a mathematical statement, we can get an idea how it behaves in a particular area by looking nearby.(Edit:Sorry, I just noticed you're the same guy as before.) The sum of an infinite amount of nothing certainly is nothing (stated I believe as $\lim _{x\to \infty }\sum _{a=1}^{x}0=0$ or as 0+0+...+0=0 or as $\lim _{x\to \infty }0x=0$). It'll certainly never get bigger. However, take the function f(x)=x(1/x), which for x=1/5 for instance means (1/5 + 1/5 + 1/5 + 1/5 + 1/5) or (1/5)5. What does f(0)=0(1/0) mean? Well, at every point except x=0, this simplifies to f(x)=1, which suggests that f(0)=1 as well. But, on the other hand, g(x)=1/x gets arbitrarily large (as big as you want, then bigger) as x gets closer to 0, so g(0)=infinity, so f(0)=0(infinity). So, in two slightly different interpretations of 0 times infinity, it's reasonable to arrive at two very different answers, which is why arithmetic doesn't touch it. And thank you. Black Carrot 04:12, 3 September 2006 (UTC)

No, the axioms of arithmetic don't touch it because they only mention finite numbers (one or any of its successors). I can tell you're the same guy because of that cool red sig - and you write formulae very nicely too!

Your point about 0(1/0) I'm afraid isn't correct, 1/0 is not defined by arithmetic (just like arithmetic not defining operations with non-finite numbers) and therefore not part of functional analysis in general (isn't it wonderful, btw, that from an axiomatic point of view Analysis is hardly any bigger than Arithmetic?), although it is a neat un-rigorous way of showing zero times infinity is one. You could possibly make a more rigorous argument calling the point x = 0 a singularity.

The point to note is that you can use apparently sound logical ideas to get lots of different answers, which is why Pure Mathematicians devised analysis - so there was one realm of human thought at least that was bollocks free - which is why people are able to talk nonsense when they take sound ideas about limits and apply them to real events and end up with a monkey writing Hamlet. Rentwa 11:54, 3 September 2006 (UTC)

I would still like to know if the universe will exist for an infinite length of time or not. Perhaps it goes through an infinite number of big bangs. Or perhaps there are an infinite number of universes, where I am having exactly this same thought. Or perhaps nobody will ever know.

According to Thermodynamics things get hotter and more disordered unless you keep supplying them with enegy, and since there's nothing outside the universe to put energy into it, it will end in a 'heat death' (although it will only warm up by a tiny fraction of a degree due to its size).

If you're wondering whether or not this is likely, and how reliable thermodynamics is, one of the famous physicists working at the turn of the century in quantum mechanics (I forget who - does anyone know?) said in investigating the apparently bizarre world of the sub-atomic, that he was willing to reject every Law of Physics except Thermodynamics. So I'm voting for heat death.

There is modern work that contradicts it, but I'm not familiar with it and I'd guess it was a little dubious.

Re extra dimensions etc, I think it's best to remember what the logical positivists were trying to say: if there's no good evidence for it or it doesn't help to explain things that were previously inexplicable (rather than pander to wishful thinking) then there's no reason to say it. Rentwa 15:11, 3 September 2006 (UTC)

Read Ultimate fate of the universe. --Lambiam^Talk 16:22, 3 September 2006 (UTC)

Lambiam - do you know which Physicist it was who said he was willing to discard everything except the second law? Rentwa 19:27, 3 September 2006 (UTC)

I'll take that as a 'no', then, shall I? :) Rentwa 12:58, 4 September 2006 (UTC)

Rentwa - Fair enough. There's a much better reason for it not to be taught in arithmetic - the fact that they're completely different. For the rest - I wrote an intentionally lazy and hand-waving description because I figured it'd get the point across. I'm not quite sure, though, whether you're agreeing with me or disagreeing. I'm also curious whether I'm farther in math than you are, or vice versa. I'm not familiar with the phrase "functional analysis". To put it in the most rigorous, or at least most clear, way I've learned:

1a)$f(x)=0x\qquad$

1b)$\lim _{x\to \infty }f(x)=0$

1c)$\lim _{x\to \infty }0x$ is of the form 0 times infinity, so in one situation 0 times infinity = 0

2a)$g(x)=x(1/x)\qquad$

2b)$g(x)=1,x\neq 0$

2c)$\lim _{x\to 0}g(x)=1$

3a)$g(x)=h(x)i(x),h(x)=x,i(x)=1/x\qquad$

3b)$h(0)=0,\lim _{x\to 0}i(x)\to +\infty$

3c)$\lim _{x\to 0}g(x)=\lim _{x\to 0}h(x)i(x)=0(\lim _{i(x)\to \infty }i(x))$ is of the form 0 times infinity as well, but evaluates to 1. The same steps could show that lim(x->0)x²(1/x)⁴=inf. Or just looking at their graphs, which is basically what this formalizes, could show the same thing - a flat line at one place versus a flat line at another place versus a vertical asymptote. So, the statement "0 times infinity" is ambiguous. It's not that any of the answers is wrong, it's that the right answer depends on the actual relationship between the two objects/values/measurements described. Black Carrot 21:32, 3 September 2006 (UTC)

I studied Maths up to postgraduate level, although I don't work in the field now (and I never taught in any very prestigious institutions when I did).

Argument 2) is fine I think except that there are very rigorous rules in analysis for letting you say that the value is what it looks like at the point you can't work out (obviously the graph is flat across its domain with g(x) = 1), and without my text books to hand I can't remember what they are (I'm on holiday and still spending 10+ hours a day ranting on wikipedia - how sad is that?)

I'm agreeing with you that you've got a good way of showing that 0 x infinity = 1, I'm just not sure it's rigorous without checking the rules, whereas I don't need to check the rules to know that the sum of 0s = 0 or to remember the axioms of arithmetic from my undergraduate Logic course.

'Functional Analysis' = 'Analysis' = rigorous treatment of functions, it's the broad topic that calculus falls into at university.

What you're saying at the end is what led me to analysis and the philosophy of logical positivism - that you have to think very carefully about what you mean, the symbols you use and the rules governing those symbols or you end up talking rubbish. Rentwa 22:55, 3 September 2006 (UTC)

THeres no such thing as zero probability in nature anyway. Only in mathematics. So the argument is rather sterile.--Light current 23:00, 3 September 2006 (UTC)

Rentwa - I'm in undergraduate Calc II, plus some study beyond the classroom. So, you'd get the benefit of any doubt. You've got a good point, that it takes a bit more to actually prove that the limit works that way, but I'm almost certain that the necessary argument exists, somewhere. I think that because we've evaluated those limits and ones like them in class many times, and the teachers seem pretty sure that that's how it winds up. What are some good textbooks for that kind of thing? Black Carrot 03:02, 4 September 2006 (UTC)

Light current - A fair point. Black Carrot 03:02, 4 September 2006 (UTC)

I always give myself the benefit of the doubt :) . And the more I think about it, the more 'Prove f(x) = x (1/x) is continuous' sounds like a question, so you're probably right, it's just I want to see 'blah blah (such and such theorem), blah blah (since x is a member of R) blah blah etc before I give you a tick :) . To take things to a more philosophical level (and draw attention away from the fact that I can't remember the rules for continuity), both the 'infinite monkeys' and 'Schrodinger's Cat' strike me as proofs by contradiction eg:

assume we can apply limits to real life,

do various other steps, all 100% logical,

conclude monkey can write Hamlet,

in a lucid moment realise that a monkey couldn't write Hamlet, thus proving original assumption is wrong.

Likewise:

assume quantum super position,

use various other steps, all 100% logical,

conclude cat can be simultaneously dead and alive,

in lucid moment realise cats are one thing or the other, thus proving quantum super position is wrong. Rentwa 09:21, 4 September 2006 (UTC)

Iron

What do you get when you mix oxygen with iron? 64.12.116.74 20:06, 2 September 2006 (UTC)

I'd like to help you out, but my chemistry is rusty. ---Sluzzelin 20:08, 2 September 2006 (UTC)

Ha Ha. I think you could get a lot of things (one of upto sixteen different oxides) depending on how you did it. But see iron, Iron oxide, ferric oxide to start.--Light current 20:11, 2 September 2006 (UTC)

Hehe, sluzzelin, it depends though, on temperature and for how long, but if given enough time and or heat, you will get the iron oxides light current mentioned. Philc _T^E_C^I 20:53, 2 September 2006 (UTC)

I prefer to call it "ironic oxide", since you work hard to replace your rusty old car with a shiny new car, then it turns to rust as you work hard for the next shiny new car, etc. :-) StuRat 21:25, 2 September 2006 (UTC)

Quite simple

Dirk vs. StuRat? ≈Eh-Steve 21:08, 2 September 2006 (UTC)

Hmmmm... --Russoc4 02:02, 3 September 2006 (UTC)

But to make it a fair fight, you must use both our full screen names, so DirkvdM vs StuRat. StuRat 02:18, 3 September 2006 (UTC)

Im far too common to enter such a contest!--Light current 02:44, 3 September 2006 (UTC)

Are we being pitted against each other? As if we need the incentive of others for that. And which one is supposed to be "quite simple"? Anyway, there appear to be many StuRats. For example, is this you? If we limit this to Wikipdia we get StuRat 538 vs DirkvdM 886. But to distinguish between us without limiting the search to Wikipedia we could use our real names. here's mine: Dirk van der Made, with a score of 1270. DirkvdM 06:26, 3 September 2006 (UTC)

When I picked your links I get me ahead with 362 vs. 348 for you. StuRat 07:45, 3 September 2006 (UTC)

What, you get significantly different results? Shouldn't this be the same the world over? DirkvdM 08:08, 3 September 2006 (UTC)

That's what I was expecting. How many hits does everybody else get on Dirk's links ? StuRat 11:31, 3 September 2006 (UTC)

I'll ask about this at the IT ref desk. DirkvdM 13:53, 3 September 2006 (UTC)

I should note that there's this other Dirk van der Made from the 13th centrury. Excluding him gives only 865 results. Most of these are a result of the popularity of my photographs on the Internet. Looking through that list is quite interresting - haven't done that for some time. I now see that someone thinks I have tremendous potential. I just don't know for what (my life's story :) ). DirkvdM 07:22, 3 September 2006 (UTC)

Saying you have "potential" is shorthand for "wasted potential". It's something like saying a woman has "a good personality", LOL. StuRat 08:02, 3 September 2006 (UTC)

I have some 2000 more Wikipedia edits:

StuRat's edit count

DirkvdM's edit count

StuRat 07:36, 3 September 2006 (UTC)

If you have (slightly) more Wikipedia edits than me and I get more Wikipedia hits, does this mean that I am talked about more? In other words, am more interresting than you? DirkvdM 08:08, 3 September 2006 (UTC)

Yes, apparently you are all talk, while I am a man of action. Note that thousands of additional edits isn't a "slight" amount, and I don't agree that you have more Wikipedia hits from Google (that's not what I get when I pick your links). StuRat 11:36, 3 September 2006 (UTC)

But you have to view that in relation to the total count. You have 9394 edits and I have 7628 edits. That's a difference of 1766, and 'thousands' is in my vocabulary at least more than 2000. Now who isn't a math graduate? Ok, so you have 23% more edits and are in that sense 23% more action (but is ceterus paribus? How many political parties have you started?). But based on my Google results I am 65% more talk, and thus 65% more interresting. DirkvdM 13:53, 3 September 2006 (UTC)

I said Wikipedia edits (as opposed to total edits), which favors me by 6327 to 3528. That's a diff of 2799, or 79% more for me. I can both do math AND read, whereas you, apparently, can only talk. :-) StuRat 03:43, 4 September 2006 (UTC)

What do you know, I may be a mute. You mean 'write'. Anyway, you just made that up. If you meant 2799, you wouldn't have said 'some 2000' but something like 'well over 2000' or 'almost 3000'. Also, I'm more of a help because I've got infinitely many more edits there than you. Ok, that was silly. :) DirkvdM 07:25, 4 September 2006 (UTC)

We are making up the rules of this contest as we go (and as suits us). Eh-Steve, could you emphazi your intentions here a bit more? DirkvdM 08:08, 3 September 2006 (UTC)

5 wikidollars on StuRat. And, just in case, put me in for 4 wikidollars on DirkvdM, too.  freshofftheufoΓΛĿЌ  10:04, 3 September 2006 (UTC)

Being a bit indecisive? You place 20% more on StuRat. Ist that based on the 23% more action? But then what about my 65% more interrestingness? (As exemplified by my linguistic inventiveness.) DirkvdM 14:02, 3 September 2006 (UTC)

5 is 25% more than 4, since the basis is 4. However, 4 is 20% less than 5, since the basis is 5. StuRat 04:34, 4 September 2006 (UTC)

Hmmm, I wonder how that sneaked in. Maybe I did use the wrong base. Anyway, 25 is closer to 23, so that fits even better. Btw, this reminds me of the Philippines, where (like in the US) they very oddly substract taxes from the prices and then add them back again before the sale. Thus, you often get very weird prices, but with tax they are miraculously round again. In one hamburger joint they hadn't done this right, though, calculating the substracted tax percentage based on the full price, so adding it back (based on the 'untaxed price') gave too low a result. I decided not to point this out because I had a hard enough time getting a hamburger (in a hamburger joint!). "A hamburger please" "A hawaiian burger?" "No just a plain hamburger" "A cheeseburger?" "No, a hamburger" "A what-have-you burger" "No, I just just want a plain fucking hamburger" Startled looks, but I thought I had gotten through to her. But then "What about your drink sir?" AAARghhhh!! DirkvdM 07:25, 4 September 2006 (UTC)

We saw a Dutch guy on holiday. He had 'Fuck off' tattooed on his leg. We stared at him for a long time. Eventually we went up to him. 'You have 'Fuck off' on your leg' we said. 'Yes' he said. 'Why have you got 'Fuck off' tattooed on your leg?' we said. 'It's a very useful phrase in Holland' he said. We backed away slowly... Rentwa 19:56, 4 September 2006 (UTC)

In Los Angeles, when you go to Jack in the Box for a hamburger, the Hispanic server says "Welcome to Yak in the Box" ... it must be a mighty big box ! :-) StuRat 08:30, 4 September 2006 (UTC)

This might be a challenge for me to suitly emphazi, because I just wanted to see what would happen between you two (Y'all are always quarrelling about lefty vs. US politics, as far as I can tell, more than any other 2).

So... How about a deathmatch (like giant seagull vs. Human)? ≈Eh-Steve 15:45, 3 September 2006 (UTC)

As long as it's virtual death (what else could it be over the Internet?). Btw, it's mostly over politics that we're head to head. When it comes to science and especially humour we're often of the same mind. However, in all areas we try ot outwit each other, and to some that might come across as something more serious.

So a deathmatch it is. What are our weapons? DirkvdM 17:54, 3 September 2006 (UTC)

You don't need any weapons, you're already working to arm the terrorists with nuclear weapons, so they will get me for you. StuRat 04:24, 4 September 2006 (UTC)

The Netherlands supply the US with arms? DirkvdM 07:25, 4 September 2006 (UTC)

I think it should be te person withe the fewest Google hits who wins. This shows the originality of the name. In this case, I lose by a massive amount! 8-)--Light current 18:05, 3 September 2006 (UTC)

HEY you two! My Dad's bigger than either of your Dads. So there!--Light current 03:49, 4 September 2006 (UTC)

Please dont turn this desk into a complete joke eh?--Light current 03:57, 4 September 2006 (UTC)

Damn you both for letting all this fun go on without telling me! Sure, I can't compete with either Dirk or Stu when it comes to edits or google hits, but as the RefDesk's resident right-wing, Canadian, pro-US, anti-UN, Republican, shit-disturbing Zionist Jew, I'd think I'd at least get honourable mention! Loomis 02:49, 5 September 2006 (UTC)

Maybe I'll sick you on Dirk, to counter all those nuclear weapons he wants to give to terrorists to get me. :-) StuRat 07:42, 5 September 2006 (UTC)

What? Nobody's mentioned Magical MD5 Battle? StuRat won against DirkvdM after 5 rounds. --Kjoonlee 17:43, 5 September 2006 (UTC)

StuRat: ヽ( ´￢`)ノ, DirkvdM: (ﾉд-｡). Can I get my 5 Wikidollars now?  freshofftheufoΓΛĿЌ  05:54, 6 September 2006 (UTC)

Northern Cardinal question

There was a fledgling cardinal in our yard about 2 weeks ago--it didn't look like a cardinal, but it was being fed by cardinal parents, and it couldn't fly. We were worried about it because it kept hopping into dangerous areas, like the sidewalk, etc. Now there is a red male cardinal hanging around, but no parents. Is it possible this is the fledgling? How long does it take a fledgling to get its red feathers?

Thanks!

This is a rather entertaining story until you realise it's about birds. :) DirkvdM 06:28, 3 September 2006 (UTC)

I remember when the racehorse Cardinal was retired. The headline said "Cardinal out to stud". JackofOz 12:08, 3 September 2006 (UTC)

At least it was not Cardinal Sin. --Lambiam^Talk 16:42, 3 September 2006 (UTC)

sun slowing down

i know the moon is slowly nicking the earths angualr momentum, so does in theory the planets takie angular momentum from the sun? if so, excluding events like sun turning into a red gaint (or the IAU decides to change definition of a planet again)how long would it take with the current planets to stop the sun spinning?--Colsmeghead 23:01, 2 September 2006 (UTC)

• Not sure, but since the Sun is almost 1.98×10³⁰ kilograms, and even Jupiter being a mere 1.90x10²⁷ kilograms, the combined mass of all the planets and other objects in the solar system, probably aren't enough to actually cut into the Sun's angular momentum, at least not in a way that will have a significant effect within the life time of the solar system--71.247.243.173 00:06, 3 September 2006 (UTC)

That's only 1/1000th of the sun's mass... sure it's small, but is it really negligible? Aaadddaaammm 01:14, 3 September 2006 (UTC)

It's the tides that cause Earth to lose angular momentum. Using this formula, I calculated the tidal forces that the planets exert on the Sun:

Mercury: 3.140135 x 10²⁰ N

Venus: 7.104643 x 10²⁰ N

Earth: 3.300665 x 10²⁰ N

Mars: 1.001771 x 10¹⁹ N

Jupiter: 7.446589 x 10²⁰ N

Saturn: 3.619013 x 10¹⁹ N

Uranus: 6.786093 x 10¹⁷ N

Neptune: 2.072556 x 10¹⁷ N

So if Jupiter and Venus are at a 90-degree angle with respect to the Sun, their tides will cancel each other. If there's a syzygy involving Mercury, Earth, and the Sun, and if Venus (or Jupiter) is at a right angle to Mercury, then Mercury and Earth's combined tide will almost cancel that of Venus/Jupiter. Also, if Mercury is at a right angle to Earth, their tides will cancel.

As you can see, the situation is very complex when there's 8 planets involved. With the planets cancelling and overpowering each other's tides, we probably need to run a computer simulation to find out what happens. But even if the Sun is losing angular momentum, it won't stop rotating. I'll use Earth as an example to explain why: the Moon's gravity changes the shape of the Earth, slowing Earth's rotation and in the meantime lengthening the Moon's orbital period. When the length of an Earth day is equal to the Moon's orbital period, Earth's shape will not change anymore, because the Moon will be stationary relative to our planet. When this happens, the length of a day will be fixed forever. --Bowlhover 05:38, 3 September 2006 (UTC)

But, as you say, the solar system is more complex, with all its planets and planetoids and what have you. I wonder if all planets, through their mutual attraction would in the end become stationary relative to each other. But since a given orbit period corresponds to a given orbital radius, all planets would have to merge for this to happen. Is that a state the solar system is moving towards? DirkvdM 06:37, 3 September 2006 (UTC)

No, the planets don't have any reason to merge. The force that the planets exert on each other is very small, certainly not enough to change the planets' orbits to any extreme degree. --Bowlhover 06:54, 3 September 2006 (UTC)

I think, in theory, they would eventually merge. But, since that would take far longer than the time before the Sun goes nova, it's not really important. StuRat 03:00, 9 September 2006 (UTC)

September 3

Genetic Engineering's impact on Plant Biodiversity

What are the impacts of Genetic Engineering on Plant Biodiversity? I know a bit and have already looked at http://www.biotech-monitor.nl/2805.htm and a couple of wiki articles.

Cheers, Daniel.thorpe

Basically, as people engineer plants so that they are more profitable/healthy/etc (desirable), the biodiversity goes down because the undesirable plants get unpropagated. When a disease hits that is very detrimental to a certain genome, like the desirable genome, then all those plants die. Without other genomes readily accessible, it is hard to replant. In theory, if we all converted to the most desirable genome, and then it died, well there'd be no more of that type of plant. M.manary 00:12, 3 September 2006 (UTC)

but none of those effects are specific to genetic enginering, if we all switched to one non-gm type of plant we'd go down the same road. Xcomradex 00:19, 3 September 2006 (UTC)

surely introducing wierd and wonderful genes into plants, at least in the short term, increases the biodiversity of plants? You're creating a new species. Whether this species has an effect on others to effect biodiversity, who knows?! Aaadddaaammm 01:13, 3 September 2006 (UTC)

Transgenesis does not, in itself, create a new species. Most genetic engineering of plants for commerical purposes, can be thought of as simply a way of accelerating the same changes that could potentially be brought about by many, many years of selective breeding. The modern farming methods that grow the GM plants may well decrease biodiversity, but the process of genetic engineering - transgenesis - itself is surely increasing biodiversity. Rockpocket 01:56, 3 September 2006 (UTC)

Ahh, yes but wouldn't (due to Darwin's theory) the GM Plants become the "fittest" and eventually become the new dominant species of plant in the area? Especially if they were allowed to breed, wouldn't a disease resistant, or whatever the modification was, plant become a weed-esque organism? There is also the Chance of something like Agrobacterium Tumafaciens (I think thats the spelling) could asexually transmit the changed genomes. Thanks for your help by the way. Daniel.thorpe 10:28, 5 September 2006 (UTC)

Interstellar travel

Let's assume we can aim a spacecraft in the direction of a star (or rather, where the star will be when the spacecraft gets there), fire the thrusters, and have it arrive within 15 AU of the star without any further navigation. Under this unrealistic assumption, and using current technology, is it possible to:

1. Use RTGs to aim the spacecraft at Alpha Centauri and fire the thrusters.
2. Shut the spacecraft down.
3. When the spacecraft is very close to the star, have its solar panels generate enough energy to power a light bulb.

If this is possible, is it possible to send a signal back to Earth to confirm the spacecraft's arrival? If so, how about sending a picture and some measurements back to Earth? --Bowlhover 06:15, 3 September 2006 (UTC)

If thousands of years have passed, the nuclear fuel may have lost much of it's radioactivity by then, unless you choose a fuel with a very long half life, in which case only a very low power output would be produced. StuRat 07:13, 3 September 2006 (UTC)

Was it really necessary to shove this in here? Couldn't it just have gone after mine? Seriously, what the hell? Black Carrot 20:24, 3 September 2006 (UTC)

Mine was a response to Bowlhover, not to you, so I placed it after his. I was even careful to double indent my comment so it was also clear that yours is not a response to my comment. Also, mine was only one sentence, so didn't push yours away from the original question by much, whereas yours was 4 sentences long. So what's the problem ? StuRat 02:48, 4 September 2006 (UTC)

We have to wait ten years to get news back from Pluto. Does it really seem plausible that we could set up communication with another star on a reasonable timespan? The Alpha Centauri article says it'd take 4.39 years just for the return message to flash back to us, at the speed of light. Black Carrot 06:23, 3 September 2006 (UTC)

Other than that, though, and the near insurmountable difficulty of calculating and following the right trajectory, and the additional difficulty of sending a tight enough signal in just the right direction to hit the Earth half a decade later, I don't see why not. Black Carrot 06:29, 3 September 2006 (UTC)

It doesn't take ten years to get a signal from Pluto - it isn't ten light years away. Stop picking on that poor former-planet! I'm more concerned about the amount of energy it would take to send a detectable signal from the other star. I don't think that solar panels would cut it. Clarityfiend 20:31, 3 September 2006 (UTC)

I know that sending a probe to Alpha Centauri will take a very long time, but even if it takes 18000 years, that's OK. The reason I asked the question was because I'm curious about whether any electronic equipment can survive in empty space for tens of thousands of years, and still be operational.

As a separate question, what's currently the most realistic way to travel to Alpha Centauri? Again I don't care about the time it takes, just that it's realistic. --Bowlhover 06:49, 3 September 2006 (UTC)

My plan:

1) Build a huge linear accelerator, powered by an onboard full scale nuclear reactor, in the asteroid belt.

2) It will then clamp onto a metallic asteroid which will be at the front end of the accelerator, and be approximately 90% of the total mass, with the ship being the remaining 10%.

3) Move the accelerator out of the plane containing the planets, and into a position on a line between the Sun and Alpha Centauri. This movement can be done with conventional booster rockets which are then discarded.

4) Aim the accelerator toward AC, then fire up the linear accelerator. A continuous mining operation will remove metal from the asteroid, which is then accelerated to the speed of light and ejected toward the Sun (so the stream doesn't pose a hazard to anyone). This propels the ship at approximately 1 g.

5) After about a year, the ship will be at near light speed and half of the mass will have been used up. Turn the engine off.

6) Cruise for about 4 years at near light speed, then rotate the ship the other way around (rockets can do this).

7) Repeat the process to decelerate at 1 g for about a year, with the matter stream directed into AC. This will use up about 50% of the remaining mass, which is 25% of the original mass.

8) Turn the ship slightly, near the end of the burn, to achieve a stable orbit about AC.

9) You've reached AC in about 6 years. Have fun exploring ! StuRat 11:00, 3 September 2006 (UTC)

After edit coflict:

Possible? Maybe. Pointless? Certainly. A few decades from now we will be able to build a spaceship that will overtake the one we send now before it reaches the star. This will remain true until the time it takes a spacecraft to get to a given star will approach the time it takes to develop a considerably faster spacecraft. By that time we might also live longer than that time, so people then might be interrested in doing this. But by that time we may also have other means to get that info without travelling there, so we may never travel to the stars. DirkvdM 06:59, 3 September 2006 (UTC)

Any traditionally rocket propelled ship would surely be picked up a century later by our then much faster ships, and put into a museum. This takes all the fun out of spending billions of dollars to send the first ship, doesn't it ? StuRat 07:05, 3 September 2006 (UTC)

Unless Klingons see it first and use it as a target for shooting practice. DirkvdM 07:28, 3 September 2006 (UTC)

Don't be silly. It would be the Kzinti. Clarityfiend 20:33, 3 September 2006 (UTC)

The only plausible type of interstellar travel I can think of, is outlined here, all the way at the bottom of the section. Catastrophe Surfing, kind of long winded--VectorPotential^{71.247.243.173} 11:47, 3 September 2006 (UTC)

Product Success

If I wanted to find out how successful something's been (how many copies a book's sold, say) how could I get that information reliably? Black Carrot 06:33, 3 September 2006 (UTC)

• With books it's particularly hard because in a lot of cases the numbers collected are actually the books sold to the stores. Book stores usually overorder and send the stuff they don't sell back, resulting in either books being warehoused or destroyed. That's why I personally prefer the Print on Demand model as it wastes a lot less paper. - Mgm|^(talk) 08:54, 3 September 2006 (UTC)

rubella virus

what system in the body does the rubella virus (aka German measels) occur in?

any help would be greatly appreciated!! Sammie hero 07:14, 3 September 2006 (UTC)

The Rubella article will tell all... "The virus usually enters the body through the nose or throat. Like most viruses living along the respiratory tract, it is passed from person to person by tiny droplets in the air that are breathed out. Rubella can also be transmitted from a mother to her developing baby through the bloodstream via the placenta." Rockpocket 08:20, 3 September 2006 (UTC)

Time dimensions

There are (at least) three spatial dimensions. These are expressed as exponents of length. I can visualise m, m² and m³. But in, say, acceleration, there is an exponent of time: m/s². Does this indicate a second time dimension? And can I use thinking about acceleration to get an idea of what that Second Temporal Dimension is like? The link touches on the subject, but doesn't quite help me. Also, power is kg.m²/s³. Does this mean there is a Third Temporal Dimension? And more? Also, I dn't know of any derived units that use a higher spatial dimension than three. Are there? DirkvdM 07:54, 3 September 2006 (UTC)

I always thought of acceleration as (meter per second) per second. That way I never had to imagine time squared. Now you have me confused! The SI unit for polar moment of inertia is meter to the fourth power (m^4). ---Sluzzelin 08:33, 3 September 2006 (UTC)

No, units have nothing to do with dimensions. StuRat 10:41, 3 September 2006 (UTC)

Could you emphazi that a little more suitly? Surely, m² and m³ have something to do with the second and third spatial dimension. And it takes just a small mental step to think that the use of s² indicates a second temporal dimension. DirkvdM 12:17, 3 September 2006 (UTC)

Units are generally a summary of the calculation, in this case accelaration is expressed as a vector quantity with dimension length/time², which means you square time, not you multiply two seperate time dimensions together. If there was more than one time dimension you would know about it. For a start you'd be a Tachyon. Philc _T^E_C^I 12:37, 3 September 2006 (UTC)

Well let me reverse it then. If s² is not about a second temporal dimension, then is m² also not about a second spatial dimension? Surely it is. Or let me ask this in more general terms. What does it mean to square a unit?

But let me follow your lead. Suppose I'm a tachyon. :) The article says a tachyon "can never slow to light speed or below". In other words, it exists beyond the speed limit, so not in our reality. So in another dimension? I must admit that I'm totally out of my league here, but you brought up the tachyon, so don't blame me. :) DirkvdM 13:36, 3 September 2006 (UTC)

Hehe, fiar enough, m² doesnt necesarily mean two dimentional space, though it can be used to mean this. I can also just implying a square relationship between this variable and another, ke=½mv², here we have a v², but all it is saying is that it is a square relationship between ke/½m and v, v is still a single value, and the ² does not imply that it is a 2-dimensional value.

Tachyons I brought up because above the speed of light things get complicated, for example, above the speed of light spacial and time dimensions swap round, so there are 3 time dimensions and 1 spacial dimension. Where as we recquire an infinite amount of energy to reach the speed of light, tachyons recquire an infinite amount ot decalerate to the speed of light. Now I dont quite understand the physics of navigating multiple time dimensions or anything, but tachyons exist in them, and mutliple time dimensions are possible, and exist in our univers, but we can only interact with one. Which is probably for the better, but there existence isnt anything to do with units involving time² variables. Philc _T^E_C^I 13:48, 3 September 2006 (UTC)

metres per second squared is just a shorthand for metres per second per second. It doesn't really mean metres per squared second. Skittle 14:21, 3 September 2006 (UTC)

Yeah. a m/s²=(dm/ts)/ts=(distance/time)/time. It's not that there are two separate dimensions of time, it's that you're working out an intricate relationship between a dimension of distance and the one dimension of time. You would use essentially the same math, though, if there were two time dimensions to consider. You could also have some fun linking it to spatial concepts by adding in calculus. The integral of acceleration (distance over time squared) d-time, is velocity (distance over time), the integral of which, d-time, is just distance. So, given a graph of acceleration from a starting time to an ending time, velocity is the area under the graph, and distance is the area under that graph. Both computations use the same unique time dimension, though. Black Carrot 20:19, 3 September 2006 (UTC)

There's a difference between meters squared and square meters. The former you can get when you multiply two quantities together, such as velocity; the latter involves the second spatial dimension. The confusion arises because the same notation is used for both.

That being said, there's no reason I can think of why multiple time dimensions can't exist. We just aren't equipped to detect them. Maybe you should talk to the Wormhole Aliens of Star Trek: Deep Space Nine. (Cue the Twilight Zone theme)...for your perusal. Clarityfiend 20:41, 3 September 2006 (UTC)

Not that I expect an answer to this late reply, but isn't the same notation used for a reason? Or reasoning the other way around, if these are two different things, then shouldn't there be different notations? DirkvdM 20:46, 12 December 2006 (UTC)

The fact that you can multiply 1 second by 1 second and get 1 second squared doen't imply anything about reality. I could imagine a quantity with units of seconds^100, but that doesn't mean I have created 100 time dimensions. --bmk

If two things have the same properties they are the same. Or at least that's how it should be in physics. It's not like the first time in (m/s)/s is any different from the second one (no pun). At least in the sense that length is no different whether it's width or height. But together they form an extra dimension. So if that goes for length, shouldn't it also go for time? As a variation of my first statement, the same mathematical operation must have the same meaning wherever it's applied. If you apply adding a power to length once (m² in stead of m¹) you express an extra dimension. If you do that again (m³ in stead of m²), you get an extra dimension again. How would one describe things in the fourth spatial dimension? with m⁴, right? So here, raising to a different power seems to express a different dimension. And why would the same mathematical operation have a different meaning when applied to a different unit? DirkvdM 08:45, 4 September 2006 (UTC)

If time had 2 dimensions your life could be an infinitely long spiral in some fixed area. Bounded yet eternal. Three square yards and...no, dammit, I can't think of a decent pun!! Rentwa 20:03, 4 September 2006 (UTC)

No, I'm pretty sure thats not right,time still has rules even if there are multiple dimensions, there are still issues with going backwards in it (i.e. its not possible). Philc _T^E_C^I 20:15, 4 September 2006 (UTC)

If time had two dimensions, the Universe would be unstable. Q.v. Spacetime#Privileged character of 3+1 spacetime. -- Fuzzyeric 00:31, 6 September 2006 (UTC)

No, the s² does not imply an extra time dimension. As someone said above, it's just a shorthand. The formal expression for acceleration is d²x/dt², i.e. the second time derivative of position; which does equal m/s² (for meters and seconds) which is the form people who haven't leanred calculus know. Would people still ask if there was an extra time dimension if it was expressed as v/t?

Weird sky

While I was coming home today, I noticed something weird about the clouds. They had these thick, dark bands, which were perfectly straight-edged and converged into a similar area out at sea. It kind of looks like that effect when the sun is setting, and some bands of light come through the clouds. The bands, however, were in the east, and the sun was in the west. I took photos when I walked to the beach later, but they didn't come out great, and the bands had faded lots. Thanks. --liquidGhoul 09:40, 3 September 2006 (UTC)

• If you live in the North Eastern United States, you might have been looking at what was left of a tropical storm, but I suppose you'd probably notice that. Ok, scratch that, your user page says you're Australian (:VectorPotential^{71.247.243.173} 12:02, 3 September 2006 (UTC)

Here is a pic. The photos were worse than I thought, as you can only see one of the bands (most had faded by now), and it seems they were light bands. It was just there were so many bands previously that the dark looked the minority, hence they were dark bands. It is kind of hard to see, but is still visible. --liquidGhoul 12:39, 3 September 2006 (UTC)

I assume it's the sun. When it shines through the holes in the clouds, and there is sufficient mist in the air, you'll see the rays, like you'll see a laser beam when it passes through smoke). I see that effect quite often here in Germany. —da Pete (ばか) 14:13, 3 September 2006 (UTC)

He said it wasn't the "sun filtering through the clouds effect". Could it be that they were just indications of rain far off? No, after taking a second look that doesn't look too likely either. Strange.  freshofftheufoΓΛĿЌ  14:35, 3 September 2006 (UTC)

(edit conflict)Yeah, it wasn't shining through, you can see from my shadow in the photo that the sun was behind me, not the cloud. I have seen rain out at sea, and that usually starts much lower, and is parallel. When this was obvious, there were some bands that were vertical, but most were at different angles, and converging to the same general area. The best explanation I could think of was reflections of the sun off the cloud, but there is no way in hell that it could be that perfect looking. The clouds should reflect it in all different directions. Thanks --liquidGhoul 14:42, 3 September 2006 (UTC)

Take a looksee at anticrepuscular rays. Weregerbil 15:00, 3 September 2006 (UTC)

Wow, that is awesome. I will have to keep an eye out for it more often. Thanks. --liquidGhoul 15:14, 3 September 2006 (UTC)

Yes, I would say those are anticepuscular rays. Nice photo, if you see it again and can get a good picture, stick it on the article! — [Mac Davis] (talk) (Desk|Help me improve)

Fat or Muscle?

Hello guys....I weigh too much(about 195 pounds,173 Cm height) and hence I have decided to fast one square meal.I have a hanging belly...Now if I just fast and don't do excersize,will my belly get reduced?...or just my muscle get reduced?..I checked my weight and I can read it's dropping pretty well every week.If my weight is dropping but I can't see pretty changes in my belly shape..Is it good to fast? and continue this way? or must I do excersize?...I'm trying to reduce my calorie intake to 1000kcal per day.Now I have reduced my wieght to about 155 pounds and I'm looking not that obese but my belly is still hanging...Can anyone help me in this please?...Thanks in advance..

What's your age ? You are more likely to sag after losing weight if you're older. In any event, the cure is to exercise. I suggest sit-ups for the belly. If you have lots of loose skin, though, then surgery would be required to remove it. StuRat 10:36, 3 September 2006 (UTC)

Doing sit-ups does not reduce the amount of fat on the stomach, it only increases the muscle underneath. You won't see any results from sit-ups until the fat above it is removed. You should be doing aerobic exercise, as that will increase the health of your heart (then other organs) as it has probably been damaged from being overweight, depending on how long you were overweight. This should also result in it being easier to lose weight. Go running or swimming to achieve this. Also, make sure you are getting all neccesary nutrients, a malnourished body will hold on to as much fat as possible. This is achieved through eating healthily (vegies, nuts, meat). Everybody is different as to where they will lose weight last, for you it is probably the stomach. --liquidGhoul 11:10, 3 September 2006 (UTC)

At 155 pounds, I would say the excess fat is already gone, all that is left now is to tone the muscles. StuRat 11:25, 3 September 2006 (UTC)

I agree with the advice about exercise. And as for your gut, burned fat tends to be harvested first from around the organs, and later redistributed. You may not see the final results of your weight loss for two or three months, at which time your body has finished re-balancing the fat content of your body. Anchoress 11:17, 3 September 2006 (UTC)

To add to the above: Do an activity that you enjoy which forces you to exercise. It's a lot easier to aim for a more active lifestyle than it is to start exercising all of a sudden, though the difference is really only in the perception. A sagging belly is a sign that your body isn't holding itself together, and something as seemingly unrelated as back exercise can have noticeable results. One of the most important things is keeping a routine, and you have to be comfortable doing it. Reducing your calorie intake may help, but that should never be the focus of your "diet lifestyle". I mean, think about it this way: Exercise requires concious physical action, fasting requires no extranuous act other than resisting the urge to eat. Do you really think that fasting could logically have more benefit than exercise? There are lots of studies that suggest fasting has the opposite effect on dieting, as the body goes into a calorie conservation mode and thus you gain wait easier from smaller amounts of food.  freshofftheufoΓΛĿЌ  11:29, 3 September 2006 (UTC)

When I used to go cycling a lot, it kept my tummy really trim. 62.253.52.65 13:55, 3 September 2006 (UTC)

Hearty Thanks for yout tips all friends.I'll keep all these in my mind...I have one more to ask...I'm now 24yrs old.I now look perfect and fit,say all my girl friends...But when I remove my shirt I still get embarrassed since I have loose muscles\fat whatever hanging esp the belly..But my shoulder and hip bones are almost visible and I look skinny except for my belly which is very loose...Is it just the fat or loosly packed muscles?...Now to reduce this what kind of steps should I have to follow?..Can dieting reduce this or should I have to follow the exercise as described earlier?....

Is exercise really "the cure?" Prof. Richard A. Muller disputes [1], and says the best way is just to eat less. Muscles don't "hang" it is either skin or fat that does. — [Mac Davis] (talk) (Desk|Help me improve)

Muscles may not hang, but the ligatures and bones that are supported by them do, particularly the hip and shoulders. A good posture can go a long way towards making you look healthy. I haven't seen Muller's stuff before, but I'll take a look at it now.  freshofftheufoΓΛĿЌ  05:55, 4 September 2006 (UTC)

I've read it, but I don't see what that proves. It's a non-conclusive report (more like a diary) by a high-profile physicist. Good for him that he lost 30 pounds, but it's not exactly a paper that I'd quote.  freshofftheufoΓΛĿЌ  06:01, 4 September 2006 (UTC)

That's a good article. I like the guy who wrote it. It's worth keeping in mind, though, that it did take him seven months to lose all 30 pounds. How long would it have taken if he'd excersized as well? Black Carrot 19:54, 3 September 2006 (UTC)

Something else to keep in mind is that you can still reduce your caloric intake by eating smaller meals rather than starving yourself for half the day. That helps keep your basal metabolism up. I think that's what bodybuilders do. AEuSoes1 21:03, 3 September 2006 (UTC)

Hey thanks about that...That's what I've been thinking about so far...I better take small amount of intake regularly instead of starving and sure it all goes toward a positive way...Thanks again friends...

It's best to have a healthy diet AND exercise. --Proficient 17:45, 4 September 2006 (UTC)

Insect

I believe that this is a insect belonging to the Dermaptera order, but perhaps someone can tell what family or species is it? --Andreas Rejbrand 10:15, 3 September 2006 (UTC)

Could it be an earwig ? StuRat 10:27, 3 September 2006 (UTC)

I thought I said that :) Earwig = the Dermaptera order --Andreas Rejbrand 10:41, 3 September 2006 (UTC)

Having found the insect in Sweden, perhaps it is a Forficula auricularia? --Andreas Rejbrand 19:22, 3 September 2006 (UTC)

Circumstances for watching polarized light

Hi, I live around 65 North, are my chances for getting a view of Haidinger's brush better or worse than someone living further south? I also understand from the article that there are TWO brushes, each 90 degrees away from the sun. There isn't any at 180, then? The brush sounds really awesome, I can't wait to gaze into the sky for minutes and minutes, like a moron, with all my friends wondering what I'm doing. :) 81.93.102.35 10:53, 3 September 2006 (UTC)

If your aim is to just see a Haidinger's bush, it's much easier to see on a TFT screen then in the sky. I've seen a very good webpage on it, I'll try to dig up its address. – b_jonas 17:17, 3 September 2006 (UTC)

Anyway, I doubt that there are two brushes each 90 degrees away from the sun because the position of the bush depends on where you're looking at. – b_jonas 17:19, 3 September 2006 (UTC)

I don't think Latitude makes much difference. In Seattle I see Haidigener's Brushes all the time. It's best towards evening when the band of sky-polarization occupies the zenith. If not at sundown, you'll have to stare at the dark band of sky which is 90deg away from the sun. The brushes look like a wide bow-tie shape, with two yellowish quadrants and two bluish quadrants. Also, it's much easier to see the brushes if one stares straight up and then spins around. That way the brushes appear to be rotating, and you won't just seem questionable for staring upwards, you'll instead look like a complete fool.  :) --Wjbeaty 00:49, 9 September 2006 (UTC)

STI's

If you either of your parents has an STI before you're born, excluding HIV, could you get it after your born? Please respond on my talkpage: user:100110100. Thanks!68.148.165.213 12:45, 3 September 2006 (UTC)

Sure, see congenital syphilis, and why do you think silver drops were routinely put in the eyes of newborns for most of the last century? To prevent gonococcal opthalmia neonatorum. Chlamydia trachomatis as well can be transmitted during delivery and cause infant conjunctivitis and bronchiolitis. Oh, and don't forget congenital herpes. And sorry we do not email private answers. alteripse 13:02, 3 September 2006 (UTC)

Thank you for your response. No, I have an account on Wikipedia. That's what you type in the search box to get to my talk page, but thanks for your response. How do you know of you have a STI from your parent (within the context of the above)?68.148.165.213 13:47, 3 September 2006 (UTC)

You get tested for whatever the mother has. --liquidGhoul 13:55, 3 September 2006 (UTC)

An infant with a congenital STI has a variety of problems apparent in infancy. If you are an adult wondering if you "inherited" something like that from your mother decades ago, you have bigger problems than an infection. alteripse 16:38, 3 September 2006 (UTC)

But STI's do not necessarily change genes, nor does it affect the baby prenatally. Can't STI's show up after the baby is born? I.e., affecting a person after the person is out of the womb? Or tube, in the case of invitro babies?24.70.95.203 16:58, 3 September 2006 (UTC)

STIs can indeed affect the baby prenatally. Congenital syphilis is a prime example of this. The symptoms of prenatally/perinatally acquired STDs are not typically the same as the symptoms of primary infection. For example, if you were exposed to chlamydia during birth, you are more likely to get conjunctivitis or pneumonia than urethritis. And "test-tube babies" still go through pregnancy in the womb! InvictaHOG 18:23, 3 September 2006 (UTC)

Pardon my response, I didn't make it clear. What I meant is that some STI's do not affect the baby prenatally, SOME, not all.100110100 00:04, 4 September 2006 (UTC)

You are right, a baby can get exposure to HSV2 during delivery and not develop disease. It is perhaps a matter of semantics whether you call that "getting it". Certainly it may take days or weeks for real trouble to develop (like herpes encephalitis. If you are asking if it seem healthy and can incubate for years and decades before the infection causes problems, we don't think so, or at least it is very rare or cannot be recognized as a congenitally acquired STD. HIV is about the only exception I can think of to the general rule that congenitally acquired STDs either cause trouble in early infancy or not at all. alteripse 00:25, 4 September 2006 (UTC)

Thanks for the response. Ok, can you get a get HSV2 during delievery\prenatally but be a carrier, or for a lack of better words, be able to infect other people, without showing any symptoms, even 'till the day you die'? I know that HSV2, you get get anywhere. Ok, I'll explain my situation. My parents never tested themselves for STI's and they still haven't. I am a virgin. But from the wikipedia article Herpes simplex virus, it says you can can it anywhere, & from what I garner from my talk page, InvictaHOG says that you can get HSV2 and NEVER display symptoms even by the time your dead [And come to think of it maybe even after your dead. Am I right?]. From this information, I just want to stay away from people. But that's so inconsiderate. So maybe as much information you guys could provide would be greatly appreciated. Thank you.100110100 07:13, 5 September 2006 (UTC)

I do not understand your concern. The world is full of viruses and we have all been exposed to a variety of them and carry some of them within us. I think the last sentences of my second and third answers apply here and are the limits of my expertise on this topic in this forum. You have given no reason for your fear that you are infected, and if so, that it came from your conception, gestation, or parturition. Before you make renunciations of close physical relationships for the rest of your life, pay a visit to an infectious disease consultant with expertise in virology to explain your fears and get reassurance. It might cost you a trip to a big city and $300 but if it settles this fear for you it is cheap at the price. If the infectious disease consultant assures you your fears are groundless, but you still can't shed them, a therapist will be a bigger expense and effort but might still be worth it. Don't make important decisions based on what a bunch of random guys here know ex vertice. Good luck. alteripse 10:42, 5 September 2006 (UTC) PS Either of these might be places to start based on your IP location: [2]. I think your best choice would be the pediatric inf dis dept at your local medical schood/children's hospital because those are the doctors with the most expertise in perinatal transmission; the UAlberta fellowship info says one of the 4 attendings specializes in virology. Alternatively: [3] but I would confirm ID board certification and virology interest before making appt. And it will be a lot cheaper in canada.

HSV 2\HSV-2

Can you have HSV 2\HSV-2 and never display symptoms? Please respond on my talkpage: user:100110100. Thanks!68.148.165.213 13:44, 3 September 2006 (UTC)

HSV 2\HSV-2 = herpes simplex virus 2\herpes simplex virus-224.70.95.203 17:10, 3 September 2006 (UTC)

Yes InvictaHOG 18:20, 3 September 2006 (UTC)

Ever in you life? Thanks.100110100 23:29, 3 September 2006 (UTC)

Ok, sorry let me rephrase my question: Must you display at least A symptom of HSV 2 [or otherwise called herpes simplex virus 2, herpes simplex virus-2, or HSV-2] in your lifetime, [i.e.: before you die] if you have HSV 2 [or otherwise called herpes simplex virus 2, herpes simplex virus-2, or HSV-2]?100110100 00:09, 4 September 2006 (UTC)

Why does this edible oil mixture taste bitter?

Recently I bought a mixture of flax seed oil, sunflower oil, olive oil, evening primrose oil, soya lecithin, and rice bran oil. It is supposed to give a balanced amount of Omega 3, 6 and 9, but I just bought it as it was a cheap way of buying non-fish omega 3.

I know that Flaxseed oil tastes or smells like putty, because that's what putty is made of, but it also had an unpleasant bitter taste.

Interesting. --Proficient 17:46, 4 September 2006 (UTC)

I have previously eaten all the ingrediants separately except Evening Primrose Oil and Rice Bran Oil, and none of them tasted bitter, nor are they mentioned as being bitter in Wikipaedia.

Thanks

Some of these oils (e.g. olive oil and flax seed oil) contain polyphenols such as tannin, which taste bitter to the human tongue. Maybe some of them were masked in their original states and activated through the mixing process. (Or maybe the mix uses unbalanced bitter-tasting products to begin with).---Sluzzelin 14:11, 3 September 2006 (UTC)

Bicycle seatpost has rusted into frame

Can anyone suggest the best way to remove the seatpost please? I do not mind destroying the seatpost, but not the frame. Thanks.

Is the post or the frame rusted? The best method I can think of (not as any sort of expert is to remove the seat and drop down something that will catch at the end, then pull and rotate. Good luck. --\/\/slack (talk) 15:02, 3 September 2006 (UTC)

Try a pipe wrench and twist the post, might work if it isn't totally rusted and the worst thing that can happen is you'll mangle the top of the post, which you don't want anyway. If that dosen't work you could try getting a machinest to drill it out, but I'm not sure how well that would work and there is a good chance you would wreck the frame. The only other option I can think of would be to get a bicycle shop to heat up the frame so that it expands and the post can be removed. My father had this done when his crank rusted into the frame and it didn't seem to affect the steel frame's strenth, though it did a job on the paint. Still there is risk there as well. It's also probably wise to think about the rest of the bike before you do something pricey too, is the rest of the bike worth keeping or not? That probably isn't the only thing that has rusted on it. I had this problem on an ancient racing bike that I got for free. The post is still in there, the rest of the bike wasn't worth the repair. 24.137.78.34 15:10, 3 September 2006 (UTC)

From WD-40: "Two rules get you through life: If it's stuck and it's not supposed to be, WD-40 it. If it's not stuck and it's supposed to be, duct tape it." :-) Maybe a combination of WD-40 and vise grips? Weregerbil 15:13, 3 September 2006 (UTC)

Some bicycle mechanics will remove the cranks and bottom bracket, turn the frame upside down, pour motor oil into the seat tube through the bottom bracket shell, and let it sit for a day or two, then apply some torsion to the seat post. Sometimes, the seat post lug can be slightly spread to facilitate dislodgement. At all times, one must use a combination of force and restraint so that the frame is not damaged. Because this often takes experience, you might consider having a bicycle mechanic do this task if your initial attempts are not successful.--Mark Bornfeld DDS 16:24, 3 September 2006 (UTC)

I would either take Mark's suggestion (you might improve on it with rust eater (dunno the english term)) or if that does not work, you should be able to either drill the seatpost out completely (you will need to fixate both the bike and the drill) or to drill a small hole down along the seatpost so you can 'fold' it into the bike frame. Another way would be to get a winding drill and create a screw thread into which you screw (and perhaps even glue it in with strong loktite (the kind for large ships) or some such) a bar with a handle. This should give you _lots_ leverage. RichiH 17:22, 3 September 2006 (UTC)

My solution would be: spray some WD40 into the crack. Leave for 24 hrs. THen, get a pair of Mole grips, tighten hard and give stem a twist. If no movement, gently tap the end of the grips with hammer. I still noemovement, spray more WD 40 and leave for another 24 hrs. Repeat process until stem is loose. 8-)--Light current 18:12, 3 September 2006 (UTC)

Although I'm in complete agreement with the utility of WD-40, in this case, a specific penetrating oil (American trademark: "Liquid Wrench") may work better for this than WD-40. Give it lots of time to work its way along the seat post, though. (And I mean lots, I'm talking several days or more.) And yes, let gravity work it down and then flip the bike and let it flow up, err, down from the bottom bracket. I also agree with whoever suggested lots and lots of torque/a pipe wrench.

Atlant 22:48, 7 September 2006 (UTC)

complex carbohydrates

finally, after clicking all over the place I get here. Question: May I please have a list of complex carbohydrates? I am diabetic, and controlling it with diet and exercise. I want a simple list of foods that are considered complex carbohydrates. Thank you Linda Johnson

The American Diabetes Association and Diabetes UK give you a summary. Though the lists posted here aren't all too comprehensive, the websites might point you to further information. ---Sluzzelin 14:51, 3 September 2006 (UTC)

Complex carbohydrates is in cookery another name for starches. For example, rice, pasta, bread, potatoes, beans. See Starch#Starches_as_food. The wholemeal kinds are to be preferred. I would not eat bananas even though listed as a starch - I expect they have a lot of sugar in them also.

You may also be interested in the articles Diabetic diet, Diabetes management, Diabetes, and low Glycemic index foods, including List of foods with a low glycemic index.

This site http://www.netdoctor.co.uk/focus/nutrition/facts/lifestylemanagement/carbohydrates.htm has a list of complex carbohydrates:

bananas

barley

beans

brown rice

chickpeas

lentils

nuts

oats

parsnips

potatoes

root vegetables

sweet corn

wholegrain cereals

wholemeal breads

wholemeal cereals

wholemeal flour

wholemeal pasta

yams

There seems to be a lot of medical quackery on the internet, so don't believe everything you read.

I do hope you are doing this under regular medical supervision - your sight is at risk if you are not. Take care. 81.104.12.75 15:14, 3 September 2006 (UTC)

Slow decrease in weight at sub orbital velocities

Hi, I know that the Concorde airliners flew fast enough to decrease the weight of the passengers from your article, and that at 7800 m/s one's weight is zero since it is orbital speed. I am wondering how fast the weight decreases in relation to speed. I realize that height also has something to do with it, but unless I am really off, this is not generally significant? Thank you for your patience. 24.137.78.34 15:01, 3 September 2006 (UTC)

It is not the speed at which it reaches altitude, it is the falling that get's you weightless I believe. — [Mac Davis] (talk) (Desk|Help me improve)

Let's see if I make a mess of the math...

The centrifugal force can be calculated with F=v²/r.

Concorde's cruising speed is(was) 2170 km/h = 603 m/s. Earth radius r=6372000 m (could add the plane's altitude but the effect is small). Flying east at the equator the Earth's rotation (465 m/s) adds to the speed: F = (603 m/s + 465 m/s)² / 6372000 m = 0.179 m/s². This is about 1.8% of Earth normal gravity (9.78 m/s²) so a 100 kg person would weigh 1.8 kg extra. Flying west you need to subtract the velocities, giving 0.00299 m/s², i.e. a very tiny difference (Earth rotation and plane speed almost cancel each other out).

Hmm, the Concorde article quotes 1% and 0.3% weight differences. I'm guessing the article assumes Europe to US flight rather than equatorial flight which I used. Earth rotational speed of 200 m/s gives 1% and 0.3%; I'll bet the article assumes a London/New York flight.

At the speeds of an X-15 you'd be 10% lighter.

See also: [4]. Weregerbil 19:12, 3 September 2006 (UTC)

Thank you very much, that was exactly what I wanted to know. I did not know that the centrifugal force equation could be used to calculate it, though it makes a lot of sense now. 24.137.78.34 20:19, 3 September 2006 (UTC)

Nikon D70 question

Hi Wickies

A quick one for ya

I have a Nikon D70 camara and did some long exposures the other night which resulted in a purple "fog" in the top right of the picture on any exposure over about 3 mins. I thought it might be some sort of light pollution so I put the camara in a dark bag with the lense cap on and tried several exposures of differing lengths from 3 to 10 mins. The purple fog persisted in the top right of each exposure. The longer the exposure the further the purple fog drifted across the picture. Any ideas what it might be? Me being a bit of a thick'o when it comes to electronics means I ain't got a clue other than thinking that something must be energising the top right (or bottom left?) corner of the photo sensor. Anyone had this problem with a digital camara before?--Eye 16:33, 3 September 2006 (UTC)

This explains the noise fog. [5] You can apparently map this into the camera for noise reduction. --Zeizmic 22:21, 3 September 2006 (UTC)

And if the camera can't do that, use one of those bagged shots in Photoshop and substract it (can't think from the top of my head how to do that, but it's possible and in other applications too probably). Ideally, you should have one for each exposure duration, but using a long one and varying the amount of substraction should also work. DirkvdM 07:42, 5 September 2006 (UTC)

Spiral path of a Hawk

What advantage does a hawk/an eagle get, when it follows a logarithmic spiral instead of an Archimedean spiral-while diving on it's prey ? Thanking you,--Pupunwiki 16:39, 3 September 2006 (UTC)

I read something about this in Mario Livio's book "The Golden Ratio." He seems to suggest that it has to do with optimizing energy. The bird, while following a particular spiral path, is able to keep its eye on the prey, while at the same time maximizing its own velocity. - R_Lee_E (talk, contribs) 16:52, 3 September 2006 (UTC)

Sidenote - From what I've gathered, Livio's thesis is to show that the reason we find the logarithmic spiral (or golden spiral) present so frequently in nature (i.e. galaxies, sunflowers, the flight path of birds of prey, etc.) can be explained in terms of energy conservation, or energy optimization. For instance, Livio shows that the reason why the golden mean makes an appearance in the sunflower ([6]) is because it allows for the maximum amount of sunflower seeds to be packed into the smallest area - thus making the most efficient maneuver possible with the energy at its expenditure. A similar phenomenon is seen in the stemgrowth of most plants, wherein each ascending leaf grows according to the golden mean. This is to help prevent the lower leafs from being shaded by the leafs directly above them. The 'golden mean' itself seems to be a kind of sweetspot in nature. Various processes within nature, whether living or non-living, seem to 'settle into' the golden ratio 'groove.' - R_Lee_E (talk, contribs) 21:06, 3 September 2006 (UTC)

(sigh) The obvious spirals in a sunflower are not logarithmic: the angle between the spiral and the radius approaches a right angle, until at some point that series of spirals fades out and is replaced by the next. [7] [8] Nor is there any necessary connexion between logarithmic spirals and the golden ratio. —Tamfang 22:44, 3 September 2006 (UTC)

No connection between the logarithmic spiral and the golden ratio? Golden spiral "In geometry, a golden spiral is a logarithmic spiral whose growth factor b is related to φ, the golden ratio." - R_Lee_E (talk, contribs) 22:55, 3 September 2006 (UTC)

No necessary connexion, I said. Yes, you can find a special logarithmic spiral whose constant is the golden ratio (or any other real number ≥1), but I'm forever seeing all log.spirals sloppily called "golden" or "Fibonacci" and it's best to avoid encouraging that. —Tamfang 06:24, 4 September 2006 (UTC)

It has been claimed that dogs, to catch a frisbee, like baseball players catching a ball, maintain an optical constant angle: How Dogs Navigate to Catch Frisbees. Indeed, if you miss the frisbee/ball and it zooms just past you, the angle will change quickly. It follows that if the angle doesn't change it cannot zoom just past you. Either it hits you (and hopefully you catch it), or it is not approaching. The same strategy may be followed by the diving bird. In a plane, with a stationary target, this implies a logarithmic spiral: the angle between the tangent vector and the vector to the centre of the spiral is constant. I'm not sure what it means in a 3D context. --Lambiam^Talk 02:55, 4 September 2006 (UTC)

drawing molecules

what software do people use on wikipedia to draw and upload the png's of molecules like styrene?

The note on Image:Styrene.png indicates it was drawn with ChemDraw. Images are uploaded with any web browser.- Nunh-huh 17:38, 3 September 2006 (UTC)

An excellent free software is ACD ChemSketch [9]. --Andreas Rejbrand 20:31, 3 September 2006 (UTC)

see also Wikipedia:WikiProject Chemistry/Structure drawing workgroup —Pengo ^{talk · contribs} 12:32, 6 September 2006 (UTC)

600/1000V

I should know this but am ashamed to say I dont. What does 600/1000V mean when marked on single electric cables?--Light current 18:33, 3 September 2006 (UTC)

Cables are marked with all sorts of things. This voltage is the rating of maximum voltage that the wire can hold, and you can hold it in your hand. This is usually welding cable (600 V). All you would want to know is here. [10] --Zeizmic 01:21, 4 September 2006 (UTC)

I could not find the meaning in that source of the 600/1000V rating. Why are there two numbers and a slash? Does it mean that the maximum voltage is (600/1000)V = 600mV? --Lambiam^Talk 03:03, 4 September 2006 (UTC)

Neither could I. Ive seen it on British cables and that ref was for US underwriters labs. So it may be specific to Europe or just UK. The voltage rating is either 600v or 1000v obviously under different conditions. What are those conditions?--Light current 03:10, 4 September 2006 (UTC)

I would guess 600v when enclosed (eg in a duct with other cables) and 1000v when laid in the open.--Shantavira 06:59, 4 September 2006 (UTC)

I believe the first number is maximum voltage between wire and ground, and the second number is maximum voltage between two wires.[11][12]. Weregerbil 12:02, 4 September 2006 (UTC)

Ahh thats it! Thank you!! I thought it had to be something simple--Light current 12:51, 4 September 2006 (UTC)

So its probably single phase against 3 phase. Notice 1000 = 600 x sqrt(3) (approx). I wonder if this applies to all the other dual voltage specs.--Light current 13:30, 4 September 2006 (UTC)

600 watts/1000 volts perhaps? --Proficient 17:47, 4 September 2006 (UTC)

I dont really think so!--Light current 00:45, 5 September 2006 (UTC)

An extract from BS 6231:2006 Electric cables. 600/1000 V PVC insulated cables for switchgear and controlgear wiring here (BS=British Standard) says that 600/1000 V cables are "intended for use at alternating voltages not exceeding 600 V to earth, and direct voltages not exceeding 1000 V to earth". It's puzzling that the ratio between the two numbers is not √2, but perhaps this is to allow for distorted power waveforms that have higher crest factors than pure sine waves. --Heron 20:47, 4 September 2006 (UTC)

So now we have two contrdictory stories. One from BSI and one from a US cable manf. So obviously these markings do not mean the same here as they do in the US!--Light current 00:50, 5 September 2006 (UTC)

600/1000V shows that the cable is a Trirated Cable, rated by CSA and UL to 600V and BS6231 to 1000V. [13]

Question about getting fluids Intravenously

I've tried to read Intravenous therapy, but if the answer is there, it's either been added since I last checked, or I didn't understand it. What I'm wondering is, in as basic terms as possible, how does the body accept fluid in an IV? I can understand drugs, cause those are supposed to be going in the bloodstream, and get there whether taken orally or any other way. But I'm just talking about fluids, like for dehydration. I'm sure (I guess) that when you drink water, some of it goes into the blood, but surely not all of it, the rest.. comes back out. Yet if given water (or, water/solution, whatever it is they actually give you) in an IV, it somehow still ends up being excreted. How does it not just all end up watering down the blood, but actually gets everywhere it needs to go, as it would from the stomach? -Goldom ‽‽‽ ⁂ 20:10, 3 September 2006 (UTC)

in the drinking case, the water that comes back out comes out via the bloodstream, after being absorbed from the small intestine and then collected at the kidneys. so when you get drugs by iv, you simply cut the intestines out of the loop, and pee out the excess as normal. Xcomradex 21:36, 3 September 2006 (UTC)

I think you have a basic misunderstanding of how water is distributed normally. The way it gets from the intestines to everywhere else is via the bloodstream. That is, it gets absorbed thru the intestinal walls into the bloodstream, then is delivered to the individual cells via capillaries, and is then absorbed thru the cell walls. Excess water is absorbed from the bloodstream by the kidneys and the excreted as urine. The only parts that may be dried out as a result of getting all your fluids intravenously are within the digestive tract. While your body has some capacity to keep the mouth and digestive tract moist with saliva and mucous (generated using water from the bloodstream), this capacity can be reduced by certain conditions or medications. If this method is reduced and liquids are no longer consumed normally, dry mouth can occur. For this reason, nurses will frequently dab the mouth with moist swabs or give the patient ice chips (if they are awake), to alleviate dry mouth. StuRat 22:26, 3 September 2006 (UTC)

Also, eating food but not drinking any fluids would be bad, causing constipation. Fortunately, if a patient is not allowed or able to drink fluids, then they aren't allowed or able to eat, either. StuRat 22:31, 3 September 2006 (UTC)

TFTs v CRTs

How reliable are TFTs now? Are they as reliable as CRTs?--Light current 20:53, 3 September 2006 (UTC)

I doubt it, you can have CRTs which are over 20 years old. I doubt that TFTs can last that long. --liquidGhoul 23:40, 3 September 2006 (UTC)

Any ideas how long TFTs last?--Light current 23:55, 3 September 2006 (UTC)

Shouldn't CRTs last pretty much forever? I know that TFTs don't, but not for how long. I remember reading about organic LCD screens, the are supreme in all areas concerning the picture, but they die in a few years. — [Mac Davis] (talk) (Desk|Help me improve)

Not for ever. See [14] 01:59, 4 September 2006 (UTC)

My Sony GDM FW-900 CRT (a pretty expensive one) died after three years, just after the Sony waranty expired. I had to resort to legal threats (based on the EU legal waranty) to get them to replace it. DirkvdM 07:48, 5 September 2006 (UTC)

Yes but was it the tube itself that failed? THats what im asking about--Light current 19:46, 6 September 2006 (UTC)

Fructose - how much is too much?

The fructose article says that eating fructose has some negative effects. How much is too much? How many apples is too much, so to speak. Thanks// Jack Daw 20:53, 3 September 2006 (UTC)

The question is equivalent to asking how much sugar is too much. It depends on your age, size, metabolism, activity level, other carb intake, etc. It does appear to contribute more to obesity than an equivalent amount of glucose. alteripse 00:18, 4 September 2006 (UTC)

One politician over here in Sweden reportedly eats 30 apples a day, he's 60+ I'd suppose, quite fit for his age and looks generally healthy. Got me curious... Jack Daw 13:30, 5 September 2006 (UTC)

Fructose is after all, just sugar. As I say, it is not the substance that is toxic, it is the dose. — [Mac Davis] (talk) (Desk|Help me improve)

That's the layman's answer, Mac. The advanced answer is that a mole of fructose may be more harmful than a mole of glucose, because fructose raises uric acid levels (which reduces hepatic sensitivity to insulin) in liver cells, may not be detected as well as glucose by the satiety and metabolic homeostasis neurons in the hypothalamus, and does not serve as an efficient insulin secretagogue in the pancreas. alteripse 01:06, 4 September 2006 (UTC)

Ahh! Fructose will kill us all!!! :) — [Mac Davis] (talk) (Desk|Help me improve)

PS: Sometime's it's the substance that's toxic, not the dose. Uranium for instance has no natural metabolic use in the body - it just sits there and zaps your cells until you get cancer. Any dose above zero is toxic. --bmk

(veering off topic) ... but see radiation hormesis.--Shantavira 07:08, 4 September 2006 (UTC)

BMK, well then you're in trouble, because you've been eating uranium as soon as you started to eat solid food. See the FDA. And your understanding of the risks uranium poses is way off; the stuff is much more chemically toxic than it is radiologically toxic (which isn't difficult, because its hardly radioactive at all). --Robert Merkel 00:48, 5 September 2006 (UTC)

September 4

Just been reading about SMART-1

Why are we humans so quick to crash high-speed objects into the surface of alien worlds without a single thought for the consequences in terms of it being seen as an act of aggression by potential natives?

You believe in the man in the moon, then? 8-?--Light current 00:13, 4 September 2006 (UTC)

Absence of evidence is not evidence of absence - maybe they're up there but they live deep underground. Maybe they think we suck already and this just confirms it. I think we've done some very foolish things when it comes to space exploration - like sending out probes containing data which would allow any potentially hostile alien species to pinpoint the exact location of our homeworld. --84.68.214.65 00:20, 4 September 2006 (UTC)

The Voyager/Pioneer probes are the least of our worries. Space is *big* and the chances of them being intercepted and picked up by a passing interstellar spacecraft are very, very, very small. Factor in the probabiliy that the aliens may be explorers, rather than conquerors and I wouldn't stress too much about that. We have, however been bleeding vast quantities of radio waves into space for the past century or so, basically turning the earth into a giant flashing 'something is going on here' beacon. Anyone/thing sentient and looking in the right direction within 100 LY or so already knows about us - and most probably knows *a lot* about us. --Kurt Shaped Box 00:33, 4 September 2006 (UTC)

Well theyd have to live deep underground to have survived all those impacts that the cratering shows has happened. And what do they live on, considering theres no water?--Light current 00:23, 4 September 2006 (UTC)

Maybe they live deep because it's warmer down there, nearer the core? Has it ever been proved that there's no water on the moon? --84.68.214.65 00:50, 4 September 2006 (UTC)

How did they get down there in the solid rock?--Light current 01:24, 4 September 2006 (UTC)

The onlyUsually, crashing is done by mistake. Everything else is simply a landing. AEuSoes1 01:27, 4 September 2006 (UTC)

Actually, the SMART-1 spacecraft appears to have been intentionally crashed into the moon at high speed so astronomers could examine the dust could. Wasn't something similar done with a probe ramming into Halley's Comet ? StuRat 01:37, 4 September 2006 (UTC)

The space mission I think you're talking about is Deep Impact, and the comet is 9P/Tempel. --Bowlhover 05:05, 4 September 2006 (UTC)

But that wouldnt bother the moon men at all surely: because they live under the surface! 8-)--Light current 01:49, 4 September 2006 (UTC)

Meteors hit the moon all the time, so the 'crash' would be a normal occurrence in that environment. (Then again, tropical cyclones are normal and they kill people - we'd be pretty upset if alien scientists created one artificially "just to see what it was like".) Peter Grey 02:07, 4 September 2006 (UTC)

Are you suggesting Hurricane Katrina was an attack on our homeland by an alien race that hates our democratic ideals? Lets launch a War on Extra-Terrestrial Terror, shall we? Rockpocket 06:15, 4 September 2006 (UTC)

As to the 'why', we don't think much about destroying life here on Earth at a massive scale, so 'we' don't realy give a shit. As to whether that's a nice thing to do, that depends on which chances you are willing to take. This reminds me of those Indian religious freaks who whipe the floor before them to prevent them stepping o bugs, which are, after all, also living beings. In the case of extraterrestrial life, the chances of that existing i na specific place are so slim that if we'd want to eliminate that risk, we couldn't do anything at all. Hell, we even accpet the death of half a million of our own kind each year for the sake of transportation. And those are deaths we know will happen and could even greatly reduce without much negative side-effects. And still we do it. As to whether it would be wise - would they retaliate? If we don't detect them they probably live on such a different level that they may not even know what hit them - jut like we think hurricanes are a natural phenomenen. DirkvdM 07:59, 5 September 2006 (UTC)

Beer-- why is it fattening?

Is it the alcohol, or the sugar/carbs, or both?--Light current 00:20, 4 September 2006 (UTC)

Beer is not really fattening at all. People tend to blame it on the beer when it is really the lifestyle that usually accompanies people who drink significant amounts of beer. i.e. sedentary jobless man that sit on the couch and watch tv all day lifestyle. — [Mac Davis] (talk) (Desk|Help me improve)

Are you really sure? I think its 200 cal /Imp pt It tends to make me put on weight.--Light current 01:14, 4 September 2006 (UTC)

The calorific content of drinks like vodka and rye come from acetate. Ethanol is converted to etanal and then acetic acid in a two step process in the body. Acetic acid is essentially a very short chain fatty acid (it doesnt have enough carbon to make it aliphatic, but it undergoes the same chemistry). As such alchohol has only slightly less biological energy content than vinegar. Also, the other ingredients in beer and other spirits, such as sugars and various organic matter, adds to the bottom line (and the waist line).Tuckerekcut 01:44, 4 September 2006 (UTC)

OK so its the carbs and the sugars that do most of the damage. But if you go for low sugar beer, it means it has more alcohol usually? And is the converse true?--Light current 01:52, 4 September 2006 (UTC)

Don't just blame the carbs--a shot of vodka (the regular stuff contains little more than ethanol and water) is ~50 calories. A pint of beer can run you 120-350 calories, depending on the brew. Mixers, of course, jack up the calorie content, too, as well as the greasy pub fare, and the following day's relative lack of activity (whilst battling a hangover) only makes the situation worse. Bottom line: total calories, in the form of sugars, fats, proteins or alcohol, is the most important number when watching one's diet, not the number of grams of carbs or fat. Net caloric balance is where it's at! Drink your beer! Just be sure to jog to the bar & back to help even things out! -- Scientizzle 02:35, 4 September 2006 (UTC)

• It's only fattening when you don't use the calories you take in. -131.211.210.11 07:11, 4 September 2006 (UTC)

See also beer belly.--Shantavira 07:11, 4 September 2006 (UTC)

It is also a result of the food that tends to be eaten with beer - e.g., peanuts, pizza... BenC7 10:59, 4 September 2006 (UTC)

Well I tend only to eat 1 packet of peanuts per session and no pizza etc!. I tend to eat before drinking to try to protect the organs--Light current 12:57, 4 September 2006 (UTC)

Beer is not fattening. However beer is extremely energy dense. So when you consume beer, you get to your daily requirement of energy very quickly. And so your other consumption of fatty food, quickly turn into belly fat. Remember, belly fat comes from other fatty food and not from beer. Ohanian 22:13, 4 September 2006 (UTC)

Thats not true contrary to popular belief you do not have to ingest fat to become fat, fat is simply stored energy, though comprised of chemicals, that may not be available from the beer, the energy that needs storing is obtained from the beer. And so beer does make you fat. Philc _T^E_C^I 20:22, 5 September 2006 (UTC)

OK but its the same difference!` I consume the energy fronm the beer instead of from my food which then goes to make fat? Makes sense--Light current 22:21, 4 September 2006 (UTC)

It's just like any other food. If you drink too much, then you will get fat. --Proficient 03:38, 6 September 2006 (UTC)

War between humans and another species on another planet in the solar system?

Suppose that our constant 'crashing of stuff into their planet' annoys them and they decide to do something about it and declare war - in what form would such a war take place?

If we assume that the alien species lives on a reasonably close planet (let's say Mars for the sake of argument) and has a similar level of technological development to us, then wouldn't the 'war' actually be a bit of a damp squib? Both they and we would be reduced to using rockets to launch bombs/heavy objects at each other's worlds, which would take several months to reach their targets, leaving plenty of time for them to be detected and diverted/destroyed in space.

Yep - interplanetary war would be pretty boring without manned warships and/or long-range laser cannons. :) --Kurt Shaped Box 00:47, 4 September 2006 (UTC)

(fell asleep, edit conflict) Most astrophysicists and astrobiologists say that any civilization advanced enough to be able to proceed in interstellar warfare would not. Kind of a age=wisdom=pacifism thing. — [Mac Davis] (talk) (Desk|Help me improve)

If the Martians were smart, they'd launch a small pod filled with a selection of interesting local bacteria/virii at the earth without even initiating contact with us to declare war. That way, we'd never see it coming. Billions dead if they chose the right bugs. --84.68.214.65 01:05, 4 September 2006 (UTC)

Despite the War of the Worlds book, microbes from one planet are unlikely to be effective against life forms on another. In order to be effective parasites, microbes must be adapted to their hosts. StuRat 01:20, 4 September 2006 (UTC)

We've been sending spacecraft to Mars for years. Most of them were probably covered with human DNA. If there are any Martains, they're probably aware of our genetic code. To the Martians, suddenly having a bunch of alien probes descending from the sky would seem very threatening indeed. It would only be common sense for them to examine the probes for evidence of their origin and for information about the species that sent them, just in case it became nescessary to defend themselves against an unknown enemy from space. Once you have DNA, you can figure out nasty things to do to the creatures that bear that DNA. --84.68.214.65 02:36, 4 September 2006 (UTC)

Really? You mean like the amazing success we - with "a similar level of technological development" - have had studying the DNA of influenza and the mosquito? And we know the fundamental basis of their genetic code and have them to test our "nasty things" out on. Rockpocke

Actually, all Martian probes are thoroughly scrubbed before liftoff so as to prevent contamination. It doesn't eliminate all microbes, but it certainly means that they're not "covered" in human DNA.AEuSoes1 21:05, 4 September 2006 (UTC)

t 06:10, 4 September 2006 (UTC)

And directed energy weapons like lasers would likely be ineffective because of the inverse square law. A more feasible scenario, perhaps, would be redirecting asteroids into collision courses with the Earth, particularly as ones made of ice make excellent nuclear rocket propellant. --Robert Merkel 01:28, 4 September 2006 (UTC)

Are you sure it would be so easy to detect a nuclear missile? Terrestrial warning systems look for launch plumes, and we've got it easy because the launches are so close. If Mars launched a ballistic missile at us, we wouldn't see the launch, especially if they were clever enough to do it on the far side of the planet. And a missile is orders of magnitude smaller than some of the asteroids we periodically discover in the neighborhood, so we wouldn't be able to see it once its motor went dark. Our only warning method would be to insert surveillance satellites into Mars orbit and hope they don't shoot them all down. Melchoir 02:06, 4 September 2006 (UTC)

Don't we have some sort of system already in place that routinely scans an area of space around the earth for objects and tracks them (radar based?)? I don't know what it's called but I've seen it on the news - they use it to locate and keep tabs on pieces of debris from our spacecraft that may be hazardous to future missions. Wouldn't that detect anything on a collision course with the planet? --Kurt Shaped Box 02:19, 4 September 2006 (UTC)

Yes, but anything coming from deep space at very high speed may not be detected in time to do anything about it (though of course the faster it goes, the more shielding you'd need to get it into the atmosphere, and the easier to detect it would become). However, one might suppose that missile defence technology might have improved somewhat by the time this becomes an issue. --Robert Merkel

What if the martians launch several nuclear bombs in quick succession, each one targeting a different place on Earth? I'll be surprised if anyone detects the bombs before they get extremely close (like within 1000 km), because SMART-1 was only magnitude 19 when it was orbiting the Moon. I'll be even more surprised if anybody can intercept an interplanetary spacecraft that doesn't want to be intercepted. There's hundreds of billions of metres between Earth and Mars, and a spacecraft is at most only several metres in size. --Bowlhover 04:21, 4 September 2006 (UTC)

We'll have at least enough time to launch the same sort of barrage back at them, ensuring ourselves the last laugh. Dead.  freshofftheufoΓΛĿЌ  05:44, 4 September 2006 (UTC)

I think it's clear at this point that our only self-defense option is to pre-emptively bomb the tar out of the planet as soon as possible. With any luck it'll send a strong message to the Asteroid Belt, too. Melchoir 07:09, 4 September 2006 (UTC)

No need to worry about the Asteroid Belt, the Martians already blasted them. :-) StuRat 08:22, 4 September 2006 (UTC)

So Astero was the solar system's version of Atlantis? DirkvdM 08:35, 5 September 2006 (UTC)

Probes that have been sent to other objects in space have to be sterilized (USA and USSR signed a treaty on that). Their biggest fear is to discover life on Mars... and then to be forever in doubt about whether or not it's not from our own planet. However, the Mars 2 and Mars 3 in 1971 from the USSR are said to have been poorly sterilized or simply not sterilized. But why would an alien race declare war upon an unknown (and possibly much stronger) species for just a dozen of probes on their entire planet?Evilbu 21:51, 4 September 2006 (UTC)

Imagine if alien probes of unknown origin started landing at various points on the earth's surface and regular intervals, taking readings/samples, then transmitting data offplanet. Provided that the governments of the world didn't manage to successfully cover it up, humanity would literally be *shitting* itself, due to fear of the unknown - "there is something out there that is interested in us and we don't know why!". You can bet that the military would have their best brains trying to figure out where the things were coming from, how they worked, what exactly they were doing, the technology involved in their manufacture, and coming up with possible strategies for defense of the planet in case the probes were only a prelude to something much bigger. A pre-emptive attack against the alien homeworld would certainly be an option raised at the meetings - "humanity must prevail at all costs", "violation of our territory by forces of unknown intent", "the enemy may walk amongst us at this very moment", "violence in self-defense", etc. --Kurt Shaped Box 23:43, 5 September 2006 (UTC)

In the history of mankind if two cultures met one easily overpowered the other because they were more technologically advanced. In the case of species from different planets, that would also likely be the case, just to a larger extent. So either they are very inferior to us, in which case they couldn't do anything, or they would be very superior to us, in which case they would have technology even we at the ref desk don't know about (assuming we're all humans - over the Internet you never know who's at the other end). So the question is unanswerable.

Another approach is to compare it to conflicts between different species here on Earth. We like to think we're superior to bacteria, but we rarely mange to stop them making us sick. So maybe the term 'superiority' doesn't apply if the species are too dissimilar, which they are likely to be in the case of species from differnt planets. Maybe we'd even be unaware of each other and consider what happened to be a natural disater or (more literally) an act of God. DirkvdM 08:35, 5 September 2006 (UTC)

"Most astrophysicists and astrobiologists say that any civilization advanced enough to be able to proceed in interstellar warfare would not. Kind of a age=wisdom=pacifism thing" — another example of why physical scientists don't make the best moralists or politicians. They also thought that after World War II, life would just be peaches and cream since nuclear power and nuclear weapons would ensure that everyone would learn to love their brother. Reality was a little messier. --Fastfission 14:36, 5 September 2006 (UTC)

Scientists thought that? I thought that was the politicians. Anyway, whoever came up with that plan had a very short memeory, because it was exactly such a standoff that led to WWI. DirkvdM 17:25, 6 September 2006 (UTC)

Abingdon Island tortoise

Since this species is nearing extinction, and there is currently only a single individual left (a male named "Lonesome George"), could it be cloned to continue the species ? Also, if male turtles have an XY chromosome pair, I would think that two X's could be taken from two cells, and the Y discarded, to clone a female from the male. A female of a similar species could be drafted as a surrogate womb, and the embryo implanted surgically (sorry if this is the wrong terminology for an egg-laying species). Is there any reason this wouldn't work ? I do realize the lack of genetic diversity would not be ideal for the species, but think it would be infinitely better for the species than extinction. StuRat 01:12, 4 September 2006 (UTC)

The whole reason for sex (comments allowed) is to correct for genetic error. Sometimes the errors are good things, but mostly not. Even if there were both a male and a female, it would be difficult to keep the species going because of the lack of genetic diversity. Still, if they can clone dogs... --Zeizmic 01:30, 4 September 2006 (UTC)

I guess a good question here would be, have there been any reports of clones being able to give birth?  freshofftheufoΓΛĿЌ  05:40, 4 September 2006 (UTC)

Sure, Dolly the sheep had kids (well, lambs, actually), and plenty of cloned mice have reproduced. Rockpocket 05:45, 4 September 2006 (UTC)

I actually checked that article (and others) to make sure before I asked. There's no mention in it of her lamb, though I see now it mentions it in the picture. Bah.  freshofftheufoΓΛĿЌ  14:01, 4 September 2006 (UTC)

I would say your proposal is theoretically possible using current technology, though it would be very challenging and thus improbable. The inefficiency of cloning such a poorly studied animal notwithstanding, there are a few complicating factors. Harvesting different chromosomes from different cells during mitosis, then reconstituting them for successful nuclear injection could be tough. Using a difference species as a host would also complicate matters (consider Mitochondrial DNA). Overall, the track record for cloning of endangered species is not good. Rockpocket 06:02, 4 September 2006 (UTC)

I'm not sure we have the technical capability to extract single X chromosomes from XY pairs and use them to form XX pairs. --Lambiam^Talk 06:43, 4 September 2006 (UTC)

Picking two Xs from metaphase spreads and chucking them back together in a tube with the rest of the autosomes wouldn't be too difficult, i would have thought, with the right equipment. Making sure it viable for nuclear injection is a different kettle of fish, however. Rockpocket 07:10, 4 September 2006 (UTC)

How big is the turtle? Where does it come from? What is the cause for extinction? The best chance for this species is finding a remnant population. It would not work to clone the current turtle, cloning technology is not that advanced as to save a species in such a poor state (and I doubt any state). --liquidGhoul 06:49, 4 September 2006 (UTC)

It's a giant Galapagos Tortoise of the species Geochelone abingdoni. I believe that the sole remaining member of the species was moved to the Charles Darwin Research Station in the Galapagos Islands, after the remainder of the population was wiped out on Abingdon Island (one of the Galapagos), due to introduced species (such as rats, which ate their eggs). StuRat 08:10, 4 September 2006 (UTC)

Damn, then the chances of a remnant population are remote. I was hoping it was a small turtle from the Amazon or something. The Geochelone article doesn't mention this species, are you sure you have up-to-date taxonomy? --liquidGhoul 14:18, 4 September 2006 (UTC)

The article is at Lonesome George which says he is of a sub-species: Geochelone nigra abingdonii. Rmhermen 02:18, 5 September 2006 (UTC)

Upon reading that article, there sounds like there is some hope for finding another specimen. There are hundreds of Galapogos Tortoises around the world, some of them would predate the introduction of whatever killed them. Hell, Harriet was caught by Darwin, anything is possible. Genetic testing needs to be done to find another of the same subspecies. --liquidGhoul 07:34, 5 September 2006 (UTC)

At the very least, we can hope he lives a full life, giving researchers another 20 years or so to figure out if his sub-species can be cloned back into existance.  freshofftheufoΓΛĿЌ  06:26, 6 September 2006 (UTC)

Tracking down original references

Hi

I was wondering if there is a good way to find original references - the kind of reference that lets you say "X was discovered by Y in Z (Ref 1.). Any suggestions? If you happen to know, off the top of your head, how cytochalasin B, phloridzin, pholeretin or wartmannin were discovered,that information would be great! Thanks everyone!

Aaadddaaammm 06:37, 4 September 2006 (UTC)

yeah i've seen one of those things, its big and rectangular, and has "library" written on the front ;-) more seriously, you could probably find phloridzin and pholertin in a review somewhere, or on SciFinder if you are lucky enough to have access. Xcomradex 06:55, 4 September 2006 (UTC)

PubMed is your friend. If you query "cytochalasin" and look among the earliest references, you will find what you are looking for. This paper states:

The cytochalasins are metabolites of moulds that have been recently isolated by Dr W. B. Turner, who was also one of the group that described the chemistry of these compounds (Aldridge, Armstrong, Speake & Turner, 1967). Their special importance lies in their property of inhibiting cell division by blocking cytoplasmic cleavage. Such compounds are of value in the study of cellular function and these particular substances are unique in their ability to block cell division without preventing mitosis. Four cytochalasins have been isolated from culture filtrates: A and B from Helminthosporium dematioideum and C and D from Metarrhizium anisopliae.

The reference: ALDRIDGE, D. C, ARMSTRONG, J. J., SPEAKE, R. N. & TURNER, W. B. (1967). The cytochalasins, a new class of biologically active mould metabolites. Chem. Commun. 1, 26-2.

If you follow a similar process you should find the history of the other compounds also. Rockpocket 07:02, 4 September 2006 (UTC)

Awesome! Thanks very much for all your advice. I'll let you know how I get on. Aaadddaaammm 07:09, 4 September 2006 (UTC)

You can search google for databases of references I suppose. --Proficient 03:39, 6 September 2006 (UTC)

Scientist - Enrico Fermi

Did Enrico Fermi have a middle name? My son is doing a research project, and his teacher insists that the project not be turned in without the person's middle name. We have researched numerous sources and have not found a middle name for Enrico Fermi on any source. Thank you very much.

Enrico Neutrino Fermi? Your son's teacher needs a vacation. Not everyone has a middle name. The 'S' in Harry S. Truman, for instance, doesn't signify a middle name and was added for the sole purpose of having a middle initial. ---Sluzzelin 13:38, 4 September 2006 (UTC)

He/she already had one--it's summer vacation! And it still is for me. --Bowlhover 14:36, 4 September 2006 (UTC)

Doesnt look like he had a middle name--Light current 13:42, 4 September 2006 (UTC)

Wow. That S in Truman I didn't know about. Interesting. --Proficient 17:49, 4 September 2006 (UTC)

...Jesus H. Christ...(--Shantavira 18:08, 4 September 2006 (UTC))

Does anybody but me find it mildly irritating when a history book insists on giving full names for the individuals they mention, even when the individuals in question never used some of the names in public? ColinFine 20:16, 4 September 2006 (UTC)

The Harry S Truman thing is not the version I've heard. Both his grandfathers had names starting with S, and his parents couldn't decide which one of them to honour in his middle name so they chose just the initial. That way, both granddads could say that they were looked after. Neat solution to a tricky family problem. JackofOz 01:09, 5 September 2006 (UTC)

Then there's the fictional, although interesting, way of solving the problem as was shown on the Dick Van Dyke Show with their son, Ritchie "Rosebud" Petrie. The letters in "Rosebud" each stood for a seperate family member's name. Ritchie was bummed about having Rosebud as a middle name until Rob and Laura explained to him that he in fact had seven middle names. But back to the point, no, I don't know Fermi's middle name if he had one. And IMO, the teacher is being silly for putting forth such a requirement. Dismas|^(talk) 07:56, 5 September 2006 (UTC)

What an amazingly pedantic teacher. Nothing like making children focus in on the unnecessary details (middle names?) to make them miss the big picture and get the absolute wrong impression about scholarship. You should leave a note for them that even historians of science honestly don't give a damn about someone's middle name. We prefer first names because of the narrative form of history, but there is no strict reason to require them (E. Fermi gives enough information to work with, even Fermi would be fine if there was context given). We don't even REALLY care about specific dates in most cases—if you can remember something to the resolution of a quarter of a decade, that's usually enough. History is not about pedantic details or specific facts, it is about being able to combine lots of small understandings into larger understandings, to really understand the causes for things and the contexts of them. And Fermi didn't have a middle name, no. --Fastfission 14:44, 5 September 2006 (UTC)

While it may be unusual in the USA not to have a middle name, I don't think they are so common elsewhere.

They're not in many places. And even in the USA there are lots of people without middle names (I don't have one). --Fastfission 18:10, 6 September 2006 (UTC)

3d effects

Is it possible to create 3D efects with the help of the compouter screen?if not what extra hardware is required?

Origami — [Mac Davis] (talk) (Desk|Help me improve)

Are computer screens foldable now? - Rainwarrior 18:21, 4 September 2006 (UTC)

Well, yes. With 3D glasses of some sort, like the usual red blue ones combined with making a 3D scene in those colours on your screen. The Sega Master System had an interesting device for the game Space Harrier 3D which ran in synch with your screen, flipping one eye open and one eye closed at each frame and alternating display of the left and right views. - Rainwarrior 18:10, 4 September 2006 (UTC)

Also, there is the Stereogram or Autostereogram ("magic eye") kind of thing, which requires you to cross your eyes a little. That can also produce 3D effects. - Rainwarrior 18:21, 4 September 2006 (UTC)

LCD shutter glasses are a good way of getting full colour 3d images out of a computer screen. you need to buy the glasses and the sync box however, and you'll need to be using software that produces 3d data (eg. not wikipedia (yet)). Xcomradex 21:58, 4 September 2006 (UTC)

Philips has had 3D screens for quite some time now: [15]. --Lambiam^Talk 22:34, 4 September 2006 (UTC)

Maybe a higher end video card for producing graphic 3d effects. --Proficient 03:40, 6 September 2006 (UTC)

MAGLEV

is it possible to make a maglev such that only permanent magnets counteract the weight and side to side motion and only energized ones control its velocity so as to attain full eficiency?

Yes it is but it would take alot of magnets for the track. THats why its not done.--Light current 13:35, 4 September 2006 (UTC)

Black-holes

What determines the schwarzchild radius of the black hole?

Its mass (only)--Light current 13:33, 4 September 2006 (UTC)

Just look at the formula given in the article. 2, G and c are all constants leaving m as the only variable.

bio project question

as i was looking 4 bio projects i came across this link , which described how to extract dna from green peas , im rather sceptical if this is true ,altough it looks like an university website, i think it is a prank. learn.genetics.utah.edu/units/activities/extraction/[16] my question is that is this experiment feasible , by that i mean when i tried it out i couldnt get the same results and i was wondering "is'nt dna soo small that it can't be seen with the naked eye?212.72.3.92 15:03, 4 September 2006 (UTC)

That's interesting. It looks real to me. When I did DNA extractions in intro bio in college, it was harder, but I think that's partly because we were using adult human cells, which as the FAQ for the Utah website explains, requires a centrifuge because the amount of DNA is smaller. An individual strand of DNA is tiny, but in principle there's no reason a bunch of strands stuck together wouldn't be big enough to see and handle. What I do wonder, though, is whether this procedure really separates out everything but nucleic acids themselves, or whether what you get at the end is something more like chromatin. (Also, we have an article on DNA extraction, but it needs work.) --Allen 16:34, 4 September 2006 (UTC)

(AFTER EDIT CONFLICT) Your link didnt seem to work for me, but my guess is that it described the rather simple marburg preparation of DNA by cold ethanol precipitation. Basically, if you put a whole lot of cells in your blender for a bit to crack them open (or alternatively use a chemical lysis method), and then put the resultant slush in to water, the DNA will dissolve in the water. If you then pour out a layer of very cold ethanol on top of the water so that there are two distinct phases, you can literally pull the DNA stands out of the water solution (and into the EtOH solution) with a scratched-up glass rod. The DNA is soluble in the water, but insoluble in the cold ethanol, so it will come out of solution as a sort of whitish clear stringy gunk. For the most part, this is DNA, with a bunch of other associated proteins. This is possible for two easily explainable reasons. First, the amount of DNA in a single cell is pretty large. If you were able to take the DNA out of a single eukaryotic cell and hold it as a piece of string, it would be about 2 meters long. It would only be a few atoms thick, and would break into millions of peices in the process, but you get the idea that it is pretty big nonetheless. To package this DNA into a cell takes many many recursive packaging mechanisms, and some of these are destroyed by the lysis/precipitation process, making the DNA more bulky than it would be in situ. The other thing to consider is that everything is made up of tiny things that are invisible to the naked eye. Even though a single copper molecule is too small to be detected, I can still see the penny in my hand. Similarly, even though a single (double) strand of DNA is invisible, when they are all stuck together, one can see them with the naked eye.Tuckerekcut 16:49, 4 September 2006 (UTC)

i had tried the experiment at home with rubbing alchohol ,not ethanol (i dont have ethanol at homeas u have mentioned could this be the reason why i was not able to get the desired results. forgive me for my naivety because i 'm just a ninth grader.i appriciate your efforts at tring to answer my query.212.72.3.109 17:32, 4 September 2006 (UTC)

by the way what is an edit clash???212.72.3.109 17:34, 4 September 2006 (UTC)

For the record, it is not a prank. After developing it as a workshop for the The Edinburgh International Science Festival [17] I have personally extracted more DNA from more peas than one would think humanly possible. See here for a picture of the workshop [18] (though not of me!). Its pretty crude, its smells bad, and you often get protein contamination, but you do get floccules of DNA that you can fish out. Rockpocket 17:51, 4 September 2006 (UTC)

as i had mentioned before i'm justa naive ninth grader , could u be kind enough to enlightened me with the method u used 9 (not meant to be sarcastic in nature)and what is an edit clash ,(did 2 wikieditors clash sword s ???)212.72.8.224 18:08, 4 September 2006 (UTC)

An edit conflict is when two or more people try to edit a section or article at the same time. The second person to click 'Save page' has to do some sorting out to write what they want. Skittle 21:52, 4 September 2006 (UTC)

Also, I did almost the exact procedure described on that page in class. We used onions blended with washing up liquid, and it worked. Skittle 21:56, 4 September 2006 (UTC)

I remember passing someone at the Science Fair a few years ago who did a project like that. It worked for them, I guess. I've noticed, though, that almost none of those do-it-yourself science projects ever work for me, no matter how simple. In theory, I think I could create an antigravity system just by throwing something off a balcony. Black Carrot 06:06, 5 September 2006 (UTC)

I'll let you into a secret, the DNA from peas hardly ever worked for us at our workshop either. Its difficult getting the peas digested up enough in the timespan you have to hold the attention of the kids. In addition, you need the alcohol to be superchilled, which we used to struggle to do in the absence of a proper freezer. So what we would do is extract shedloads of DNA back in the lab using better reagents, then spike the kids reactions with the pre-extracted DNA, which they could take home with them. If one kid was being a little shit (a regular occurance) then we would not spike their extraction and tell them they obviously didn't do it correctly. Those moments used to make my day. Rockpocket 06:56, 6 September 2006 (UTC)

but can i use rubbing alchohol instead of ethanol????212.72.2.238 16:09, 6 September 2006 (UTC)

Yes you can. But make sure its as cold as possible, by putting in in a freezer beforehand. Rockpocket 20:36, 6 September 2006 (UTC)

i want to be adoctor

hi am 21 years girl ia am studying genteics engenering in jordan and my dream in this life to be adoctor in some day i wana ask if i can continue medicine after i finsh gentics and how many years i need and what i could do to know all the information that i need because i lessen that someone finish genetics and know he study medicine not from the first he continue i want to know if this true or not please help me because i need this help

am marwa abulel am have israelian nationality

I think this differs per country so your best option would be asking your student career counceler. They should be able to tell you exactly what's possible with your genetics degree and what you would need to become a doctor. - Dammit 16:23, 4 September 2006 (UTC)

You will be much better off if you can get out of Jordan for studying and practicing medicine. — [Mac Davis] (talk) (Desk|Help me improve)

How did you know that (practicing medicine in Jordan sucks)? ≈Eh-Steve 16:59, 4 September 2006 (UTC)

Where do you want to become a doctor? --Proficient 17:51, 4 September 2006 (UTC)

I guess you could do anything you want. I just figured you would be better off in Europe, Asia, or North America. — [Mac Davis] (talk) (Desk|Help me improve)

Psst, Jordan is in Asia ;-) - Dammit 22:48, 4 September 2006 (UTC)

If you are Jewish, you'd best get out of Jordan before you are murdered by terrorists. However, I'm assuming you're an Israeli Arab studying in Jordan, in which case you might be safe, except from random killings by terrorists. If you would like to work as a doctor in an English speaking country, you need to improve your English quite a bit. I suggest finishing your studies in an English speaking country, so you will pick up the language more quickly. I expect genetic engineers to mesh more closely with doctors in the coming years, with gene therapy becoming a major form of treatment in the future. So, your background in genetic engineering should be quite helpful. StuRat 03:44, 5 September 2006 (UTC)

To add to that, not only is it a good idea to have solid English skills if you want to work as a doctor in an English speaking country, but it is also an important (and extremely valuable) skill enabling you to communicate medical knowledge from the English speaking world (which is a good portion of it) into the world that speaks your native language. Even if you end up working as a doctor in Jordan, your English skills will be invaluable as you follow in the footsteps of reasearchers worldwide. Also, good luck!  freshofftheufoΓΛĿЌ  14:10, 5 September 2006 (UTC)

There is no need to get a medical degree in another country. Just on my floor of the hospital, there are doctors who got their degrees from: Nigeria, Syria, Israel, Greece, Norway, Canada, China, Tanzania (sp?), and the U.S. of course. Ones that recently left came from Panama, Australia, and Japan. Now, there is one advanatage to getting a degree in the U.S. - it can be basically free. The U.S. is very stupid about student loans. You can come to the U.S. and take out huge student loans to pay for medical school. Then, when you are done, leave the U.S. and never come back. If you don't come back, you never have to pay the loan back. The idea, as far as I can tell, is that the government thinks that if you spend a few years here you will want to stay (and pay taxes) for the rest of your life. --Kainaw ^(talk) 14:18, 5 September 2006 (UTC)

Are you sure they spent none of their University time in an English speaking country? I have a friend who became a doctor (MD) in China (Shanghai), who lives in Japan now and was finding it extremely hard to find work (he still doesn't work as a doctor), though it might be easier in somewhere a bit more accepting of other cultures. He speaks fluent Japanese and excellent English, at least when it comes to medical stuff. The reason why he came to Japan in the first place is that apparently MDs in Shanghai make less than taxi drivers! Hurray for communism!  freshofftheufoΓΛĿЌ  06:20, 6 September 2006 (UTC)

They got their degrees in their home countries. Most of them, I figured out the country from the degree (doctors feel a need to have an "I Love Me" wall with all their degrees and awards on it). Others, such as Syria, I had to ask because I couldn't make out the degree. It isn't hard for a doctor to get a job in the U.S. if they are willing to take a lower paying one in the south. Congress passed an act at least 10 years ago to speed such doctors through immigration and get them a working visa. I'm in Charleston, SC - so it is considered the south. That is probably why there are so few American doctors working here. --Kainaw ^(talk) 19:39, 6 September 2006 (UTC)

Incidentally, here is your question translated into proper English (or as near as I can get to it):

I want to be a doctor.

Hi, I am a 21 year old woman. I am studying genetic engineering in Jordan and my dream in life is to be a doctor someday. I want to ask if I can continue my medical studies after I finish genetics, how many additional years of study I will need and what I need to do to learn everything that I will need to know. I heard of someone who finished studying genetics and know he studied medicine afterwards. I want to know if this is feasible for me or not. Please help me, because I need your assistance. StuRat 04:53, 6 September 2006 (UTC)

Death of Jupiter

The article on Jupiter points out that it expends more heat than it recieves from the Sun through the Kelvin-Helmholtz mechanism. My knowledge of thermodynamics isn't great but I do know that if it is losing more energy than it's gaining then it will eventually run out. What will happen to Jupiter and its sattelites as it cools down and "dies"? What impact will it have on the rest of the Solar System? Will the same thing happen to Saturn?

Regards, Gallaghp 16:49, 4 September 2006 (UTC)

Are the energy inputs from collisions with asteroids, and the moons gravitational pulls (atmospheric tides I guess you'd call them) enough to balance the system.

Also even if the planet was radiating more heat wouldn't the Kelvin-Helmholtz mechanism cause it to shrink until its surface area was small enough for it to be radiating no more energy than it is recieving, and balance the system that way. Instead of your proposal that the mechanism continues indefinately until the death of the planet. Philc _T^E_C^I 17:21, 4 September 2006 (UTC)

A good point. I was mainly concerned with Jupiter's influence over the surrounding planets and moons, such as with it's magnetosphere (am I right in thinking it's the biggest "thing" in the solar system?) which would certainly diminish along with the planet. I know it's composed of different elements but after sufficient shrinkage is it possible that it might behave more like the outer gas giants, Uranus and Neptune? Gallaghp 21:21, 4 September 2006 (UTC)

Hm, its magnetosphere is pretty colossal so I should imagine it wouldnt be shrinking to exclude its sattelites very soon, or ever, if the thing about it stabalising is correct. About it being the biggest thingin the solar system, it is (i'll spare you the perdanticities of the sun, and its related areas of effect). I might me getting out of my depth, as my knowledge of planet behaviours is not to good, but how does jupiter behave differently? Philc _T^E_C^I 20:18, 5 September 2006 (UTC)

Far planets have nothing to do with dying suns, they seem to be very cold already, I dunno if some more cooling may change their nor our way of life. -- DLL ^{.. T} 19:49, 4 September 2006 (UTC)

Um, i think you may have misunderstood the question, hes referring to the planet dying, not its sun. Philc _T^E_C^I 20:17, 4 September 2006 (UTC)

rubella virus

i know that the rubella virus lives in the respiratory tract, but does anyone know what happens to the respiratory tract whilst it is infected??

so if anyone knows anything, please tell!! luvSammie hero 19:39, 4 September 2006 (UTC)

While the virus resides in the respiratory tract, the patient is asymptomatic. This is called the incubation period. So apparently the virus has no direct ill effects on the respiratory tract. It is only when the virus enters the bloodstream that symptoms appear, none of which have to do with respiration, except perhaps for a runny nose. --Lambiam^Talk 21:38, 4 September 2006 (UTC)

Editing problem?

I want to edit the section above on this page on complex carbohydrate, yet all I am given to edit is the Rubella virus question above. What's happening?

I get that a lot too, just refresh and try again, it usually works for me. Philc _T^E_C^I 20:33, 4 September 2006 (UTC)

Seconded. Anyone know what the underlying problem is? Does it just happen when you click an out-of-date "edit" link? Because I can recall times when refreshing wasn't enough. Melchoir 20:34, 4 September 2006 (UTC)

Could be an issue with transcluding, I can't exactly copy content at bot speed, so there is a bit of lag, but I've also been hitting a lot of server lag today, so that's probably more likely to be it--VectorPotential^{RD NEEDS A BOT (-:} 21:24, 4 September 2006 (UTC)

Usually what has happened is that – between the time you loaded the page and the time that you clicked edit – a section had been inserted or removed above the section you wanted to edit. Someone may have removed a duplicate section, added a new subsection, or a bot could have archived some of the older entries. Look at URL in your browser's address bar after you click one of the section edit links; the last part of it will be section=21 or something similar. Sections are numbered consecutively down the page; if one is added or removed, you'll end up editing the wrong section. Refreshing/reloading the page will usually fix the problem. TenOfAllTrades(talk) 21:41, 4 September 2006 (UTC)

Thanks, seems to work OK now.

Seems strange that the problem happens to a lot of people. --Proficient 03:41, 6 September 2006 (UTC)

How do the unintelligent think?

Although there has been over millenia a lot of effort put in to describe how the intelligent think, for example logic, nobody seems to care how the unintelligent reach their conclusions.

My question is prompted by what I observed recently on a long bus journey. I overheard a middle-aged woman talking to what I expect was her grandchild. She had been smoking heavily before boarding the bus. I heard her say that the sweets her grandson had were full of "good things", for example sugar; that you needed to eat a little sugar (as if it was some kind of vitamin or essential nutrient), but that eating too much sugar makes you thirsty (perhaps some warped misunderstanding of diabetes). I wonder how she could have reached these conclusions? Credibility? Inattention? Sentiment? What?

Understanding how the less gifted think would help us more priveledged people improve our thinking, and also be of use for advertising and propaganda. 62.253.52.76 21:28, 4 September 2006 (UTC)

Ill-informed? CAn be confused with lack of intelligence.--Light current 21:33, 4 September 2006 (UTC)

Your base assumption that fallacious thinking has gone unstudied is simply wrong. I wonder how you might have reached that conclusion? Ignorance? Melchoir 21:35, 4 September 2006 (UTC)

While I agree that mistakes in intelligent thinking in the form of fallacy has been studied, I am doubtful that unintelligent thinking has been - can you provide some evidence or links please?

Prospect theory. --best, kevin [kzollman][talk] 22:23, 4 September 2006 (UTC)

Obviously ignorance is studied and well understood, how else do you explain TV commercials? Why do you think people get paid millions to come up with the definitive SuperBowl beer commercial?--VectorPotential^{RD NEEDS A BOT (-:} 21:40, 4 September 2006 (UTC)

Hang on... beer commercials can be hilarious! Surely they're also accurate depictions of reality? Melchoir 21:42, 4 September 2006 (UTC)

I think your belief that this woman was unintelligent, at best, did not follow logically from the available information, and at worst, was elitist and judgmental. Sugar, a source of calories, is indeed a good thing nutritionally when not taken in excess. She might have been speaking in a sense other than nutritionally, as well, with a meaning along the lines of "sweets are good for the soul." Sugar is hygroscopic, so too much definitely makes you thirsty. In fact, for rehydration, highly sugared beverages such as soda are not favored. You should really examine your assumptions before reaching such radical conclusions about other people's intelligence. --Ginkgo100 ^{talk · e@} 21:47, 4 September 2006 (UTC)

While a packet of sugar sitting on the table may be hydroscopic, when sugar is digested I believe it releases water. (Sidenote - never try to drink blood when you're dying of thirst in a desert - the protein in it uses up more water in its digestion).

A classic example of Ignoratio elenchi or maybe Ad hominem.

Maybe she was lieing to the kid so that he wouldnt eat all of his sweets at once. Philc _T^E_C^I 00:36, 5 September 2006 (UTC)

I have a very closely related question. How do some presume, without any empirical evidence whatsoever, that they are more intelligent than others? What is the precise neurological malfunction causing this phenomenon? More specifically, what is the precise mechanism that serves to block their limited minds from considering that they may actually not know as much as they believe to know? In fact Socrates, one of the greatest thinkers humanity has ever produced, would clearly have no choice but to regard these individuals as the lowest of morons, for they, of all people, are the least bit in touch with their own ignorance. In the words of Socrates, true wisdom is only attained when one recognizes that one knows absolutely nothing. Loomis 02:31, 5 September 2006 (UTC)

I have also wondered why the less intelligent are also less concientious. According to scientists the answer is that both concientiousness and the executive functions of intelligence are controlled by the frontal lobes of the brain, so the two go together.

Is wisdom the same as intellignece? I would say not--Light current 02:44, 5 September 2006 (UTC)

Inductive reasoning is one type of "illogical" thought process which has been studied extensively. Also, if you look under fallacy and logical fallacy, you will see there are a many examples of logic errors which have also been studied thoroughly. StuRat 03:25, 5 September 2006 (UTC)

What does smoking have to do with sugar or intelligence? Black Carrot 05:44, 5 September 2006 (UTC)

If someone chooses to smoke, that either shows they don't care about their health, or that they have concluded all the evidence showing the health problems caused by smoking is wrong, in which case they are idiots. There are many, however, who are addicted, so don't really "choose" to smoke, but rather wish to stop, but are unable to do so. StuRat 04:37, 6 September 2006 (UTC)

THe implication seems to be that because the woman was smoking 'heavily' (although Im not sure how that could have been deduced since the questioner was on the bus, and the woman at the bus stop) It therefore meant she had a low intelligence.Maybe shes not wise to smoke-- but thats not low intelligence (I believe Uncle Albert smoked a pipe)--Light current 05:48, 5 September 2006 (UTC)

You've somehow decided that I was on the bus - I wonder how you reached that conclusion? In fact we were both queueing for the bus for a long time. I was trying to stay upwind of her to avoid her smoke plume.

I decided because of this sentence: what I observed recently on a long bus journey. You dont take bus journeys standing in a queue and you didnt day you were queing. So I assumed reasonably you were on the bus.

--Light current 08:51, 5 September 2006 (UTC)

I think the process the unintelligent use to reach their conclusions is different from the cold rationality of the intelligent. I think people form their ideas from sentiment and ego protection. For example, if a fellow student is much wealthier than onself, then you would tend to think he is an unpleasent person. I've noticed that the less intelligent spend nearly all of their time socialising with each other and hence have no time left to do any work - this may be due to a functional necessity to stop such petty jealousies arrising and thus leading to bullying. Most of them also definately think that matters relating to dominance in the here and now are far more important than anything else in the world.

Could there be such a thing as a logic of the unintelligent? This would require consistency. If you put a bunch of unintelligent people together, will they come up with a way of communicating that is devoid of logic as we know it but has a consistency of its own? Take insects, for example. They are way off the scale (at the bottom end) when it comes to human inteligence tests, yet they have functioning societies. Do they therefore have a logic of their own (that we humans don't understand)? DirkvdM 08:58, 5 September 2006 (UTC)

I think there's a lot of sense in that - ie the unintelligent believe in a 'set of truths' that are unrelated - ie no calculus is permitted on the different objects, so contradictions may exist and obvious conclusions are not drawn. Quite a pleasing logic from a mathematical POV however. Rentwa 09:56, 5 September 2006 (UTC)

What do you mean by unintelligent? I'm quite interested in abnormal psychology when it's actually morbid (especially autism), but if you're talking about average human moronicness it's just a hotch-potch of ignorance, poor culture, political degradation, drudgery etc. In Saturday's London Times there was an interview with a man who became prominent in homeless activism. He said (which I thought perceptive if a little damning) 'My family wasn't just poor, they thought poor and lived poor.' I remember a man in a pub telling me that 'if it was printed in the papers it had to be true', and no rational explanation of why this was false could shake his quaint view that there was a law (probably something to do with Magna Carta or Habeus Corpus) that journalists were honour bound to check every fact before commiting it to print. Or maybe he thought there was something special about the newsprint that made untruths vanish from the page, or maybe he had simply never thought about it for himself. I have a thousand similar jolly tales of working class life oop north, maybe I should write a book? Rentwa 09:08, 5 September 2006 (UTC)

It would seem that conclusions are reached based on emotion rather than logic. There is a theory - cannot remember the exact terms - but it was something like Festinger's congruency theory.

That's Festinger's theory of cognitive dissonance. --Lambiam^Talk 04:58, 6 September 2006 (UTC)

Self-expectation is very important in determining one's success or otherwise in life, perhaps more important than qualifications. That would explain why the children of the rich get rich themselves.

Is this why I'm editing wikipedia and not working on my book? :) Rentwa 10:00, 5 September 2006 (UTC)

You too, huh. We should form a "Society of Putative Writers Who've Become Temporarily* Diverted by Wikipedia". (*like, for years at a time). JackofOz 12:08, 5 September 2006 (UTC)

I prefer to think of myself as a "punitive writer". :-) StuRat 04:40, 6 September 2006 (UTC)

Oddly enough (and not to make any assumptions since Stu obviously understands 'putative/punitive') I think punning humour is often regarded as a low form of wit because it's available to those who have limited vocabularies (only requiring phonetic understanding), and is often used as a defense mechanism to cover their ignorance. Rentwa 09:45, 6 September 2006 (UTC)

I'm not sure I agree with that. Punning requires a greater degree of linguistic and lexical knowledge, and often historical knowledge, than many other forms of humour. It requires an appreciation of subtle nuances, of homophones (there's that word again, Stu), and not least, the music of language. Puns are very under-rated, IMO. JackofOz 10:51, 6 September 2006 (UTC)

Stu is a "punnitive writer". :-( Lambiam^Talk 10:55, 6 September 2006 (UTC)

Tell me about it. I usually bear the brunt of it. But rest assured, his puny wit doesn't get to me (damn, too many pointers in that link - let me try another one). Let the punic wars continue. (Is that enough history for you, Jack?) DirkvdM 17:37, 6 September 2006 (UTC)

On with the Punic wars, yes ... but, as for my "puny wit", I consider my wit to be rather elephantine. :-) StuRat 07:07, 7 September 2006 (UTC)

Better to have historical knowledge than hysterical knowledge! Get it! No? Alright, lemme try again. Being an anglophone and not a homophone, perhaps I don't quite get Jack's humour! Get it! Yes! No? Oh well, I tried. :-)Loomis 22:01, 6 September 2006 (UTC)

Huh? Either you are too smart for me or .... DirkvdM 08:13, 7 September 2006 (UTC)

OK, Loomis, let me get this straight (oops!). If francophone means speaking the language of the French, and anglophone means speaking the language of the English, then homophone must mean speaking the language of .... (you fill in the blanks).  :--) JackofOz 13:19, 7 September 2006 (UTC)

And that is the gay dope. :) DirkvdM 06:52, 8 September 2006 (UTC)

Apples and Saliva

I've noticed that my saliva becomes unusally viscous after eating an apple. This only happens with apples and not other fruits that I eat. What causes this? --Burbster 22:43, 4 September 2006 (UTC)

Anything with a lot of sugar causes an increase in salavia viscosity for me. Maybe that is it. As for the mechanism, I don't know. — [Mac Davis] (talk) (Desk|Help me improve)

I don't know the cause, but when i was a student i used to work in a lab that did genetic testing for cystic fibrosis. We used to get buccal swabs from which i would extract DNA. We found that, when the patient had recently eaten an apple (specifically), we would really struggle to get good quality DNA from the swab. I always assumed it was related to the acidity of the apple. I wonder if these two phenomena are related. Rockpocket 06:12, 5 September 2006 (UTC)

That's very interesting. I should probably look further into this. Thanks anyway guys. --Burbster 15:27, 6 September 2006 (UTC)

How natural cherry flavor is made

I would like to know how natural cherry flavor is made. Signed: "Nacherl"

steam distillation? Xcomradex 23:07, 4 September 2006 (UTC)

If it's natural, my best guess is that it's made from cherries. What am I missing here? Loomis 02:07, 5 September 2006 (UTC)

I think Nacherl is asking how they get the natural cherry flavor into the product. My guess would be they mash the cherries into juice, then add the juice to the mixture, be it candy, soda, or medicine. Hyenaste ^(tell) 02:10, 5 September 2006 (UTC)

no, i would say they distill the flavour molecules away from the pulp, to stop other components of the pulp interfering at a later stage. So i'd say distilled from cherries (or some other plant). Xcomradex 03:12, 5 September 2006 (UTC)

If you don't know the answer, then please do not substitute any random guess as a reply. --Lambiam^Talk 08:14, 5 September 2006 (UTC)

I'm not sure how you meant natural, so I may be missing the point if the question but esters are used to flavour most things. Cherry flavour can be made from ethyl heptanoate, geranyl butyrate, methyl benzyl acetate and terpenyl butyrate according to the article. Philc _T^E_C^I 10:51, 5 September 2006 (UTC)

"Natural flavor" does not mean it actually comes from cherries. It means that it is the same chemicals as are in "artificial flavors" but has been synthesized in a "natural" way (there is a specific legal definition of this; see Flavor#Flavorants). They probably have nothing to do with actual cherries. "Natural" flavors are preferred by food companies because they sell better; they have otherwise no differences from "artificial" flavors. --Fastfission 14:54, 5 September 2006 (UTC)

If I'm reading that definition right (it is somewhat ambiguous), it does say that natural cherry flavorant needs to be made from cherries, or at least from some "spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb, [etc.]". In particular, it says a natural flavorant needs to be an "essential oil, oleoresin, essence or extractive, protein hydrolysate, distillate, or any product of roasting, heating or enzymolysis", which rather restricts the preparation methods allowed. —Ilmari Karonen (talk) 20:43, 5 September 2006 (UTC)

That seems a little tricky about the natural/artificial flavors. --Proficient 03:44, 6 September 2006 (UTC)

This specific thing actually did come up in a legal fight some years ago. I don't remember all the details. But as I recall, one company sued another over the way the second company made "natural cherry flavor" (that is, benzaldehyde) from bitter almonds. The thing that struck me was, the first company also made its natural cherry flavor from bitter almonds, just in an allegedly more "natural" way. --Trovatore 03:50, 6 September 2006 (UTC)

Hey, everyone, this is the first time I've used Wikipedia, so thank you for all the good information. --Nacherl

How does human body maintain ph?

I assume that if our bodies did not maintain a constant ph, our metabolisms would go awry.

How does it do this? If you eat acid foods, does your urine become more accidic?

Is the average long term ph of the food you eat the same as your body ph? If not, why not?

Could you kill yourself by just eating acid foods all the time?

Thanks.

There are several buffer systems, of which the most important is bicarbonate, and several compensatory mechanisms (metabolic and respiratory). For further explanation you can consult a medical text on acid/base balance, or our articles on acidosis, alkalosis, metabolic acidosis, respiratory acidosis, metabolic alkalosis, respiratory alkalosis. We may have a more centralized discussion somewhere in Wikipedia? - Nunh-huh 00:01, 5 September 2006 (UTC)

negative feedback, through homeostasis, by use of blood hormones. Philc _T^E_C^I 00:34, 5 September 2006 (UTC)

Which hormone did you have in mind? Hormones have next to nothing to do with regulating acid base balance. - Nunh-huh 01:19, 5 September 2006 (UTC)

Vasopressin would affect blood ion concentrations and aldosterone is important to regulate sodium and potassium balance in the blood. -- Scientizzle 03:58, 5 September 2006 (UTC)

Yes, and the question was about pH! - Nunh-huh 04:24, 5 September 2006 (UTC)

Sorry, I should have been more clear. Hormonal alteration of ion balances is acheived by modulating ion & water transport activity in the kidney nephrons. Aldosterone stimulates H⁺ secretion, thereby raising the pH. Vasopressin will concentrate the urine, therefore also making the blood more dilute, too, and potentially reducing acidosis or alkalosis. -- Scientizzle 05:32, 5 September 2006 (UTC)

But neither of those effects are primarily mechanisms for regulating pH - they are epiphenomena. The primary mechanisms for regulating pH are those which I named in my answer. The questioner should not think that "blood hormones" are particularly important in regulating acid/base balance, because they're not. - Nunh-huh 06:14, 5 September 2006 (UTC)

I don't disagree with you one iota. I was simply giving examples of hormones that have non-zero effects on blood pH. The important point: HCO₃ and other buffers provide the immediate control over influx of acids and bases, and hormones (on a much slower time-scale) can modulate the buffer system. -- Scientizzle 02:02, 6 September 2006 (UTC)

farking edit conflicts: i remember a story about one of the early (german?) researchers (i forget the name) into blood pH eating 1 kg quantities of ammonium chloride and studying the effect, for those of you unfamilar with ammonium chloride, it is an acid with a "biting taste" (apparently) and an unpleasant ammonia smell. so i guess you can eat quite a bit of acid before fatally pushing the buffer equilibrium too far. Xcomradex 00:40, 5 September 2006 (UTC)

Ammonium chloride (also known as salmiak) is a salt, and not particularly acidic, though the evaporation of ammonia may make its solutions slightly so. Mind you, if you eat a lot of a highly acidic or alkaline substance, the immediate effect (assuming it's not acidic or alkaline enough to irritate or even corrode tissue directly) will be to change the pH of your stomach content, leading to indigestion. —Ilmari Karonen (talk) 05:33, 5 September 2006 (UTC)

Ammonium chloride is indeed a salt, but it is classically used for acidification of the urine. It has been used, for example, to test for distal renal tubular acidosis. - Nunh-huh 06:14, 5 September 2006 (UTC)

September 5

Discovering an alien probe

Let's say an alien robotic probe parachutes down to a suburban area in the U.S. Someone discovers it. What will happen next? Also, ideally, what should happen next? --Bowlhover 01:09, 5 September 2006 (UTC)

Our government would take it away. And convince that entire suburban area that the said event never took place. Russian F 01:39, 5 September 2006 (UTC)

George Bush would invade a country that wasn't involved. Peter Grey 02:10, 5 September 2006 (UTC)

Seriously, although I'm not very happy with the U.S. government, I don't think they're hiding anything about alien probes. They are hiding information about U.F.O.s, but those U.F.O.s are probably either natural phenomena or machines built by humans. --Bowlhover 03:35, 5 September 2006 (UTC)

The reason you don't think the government is hiding information about alien probes is that you do not believe there have been any alien probes. Now, if I were to tell you there have been several, and you believe me, would you still think the government isn't hiding the information? --Lambiam^Talk 08:12, 5 September 2006 (UTC)

No, but I don't believe that there have been any alien probes. How hard is it to expose the truth if many people took pictures of it? It would be hard to confiscate all of the evidence, wouldn't it? --Bowlhover 03:39, 6 September 2006 (UTC)

Why specifically the US? Is this meant as a question about US politics (as Peter took it to be)?

Given Peter's example, the person who discovers it should idealy inform international organisations first, before the US government finds out. The UN would be a good choice, but they would not have a mandate to claim it. No extra-USian governmental organisation would. So may be he should infomr a private enterprise and get them to transport it to a neutral country. But I don't know which enterprise would be willing or able and what constitutes a neutral country anyway. New Zealand? DirkvdM 09:08, 5 September 2006 (UTC)

Tell anyone except your own government first - that way there's less chance that they'd just spirit the thing away, never to be seen again. The UN, international news agencies, the Pope, anyone with a bit of clout. --Kurt Shaped Box 23:53, 5 September 2006 (UTC)

Am I the only one who doesn't think the authorities would cover it up? At least not after they confirmed for themselves what it was.  freshofftheufoΓΛĿЌ  13:49, 5 September 2006 (UTC)

Bill Clinton seemed absolutely thrilled to think that discovery of alien life had been done under his term (ALH84001). I think that the assumption that American politicians would be happier hushing something like that up does not take into account the political benefits of being the first president to announce contact with another civilization. --Fastfission 14:49, 5 September 2006 (UTC)

In a sense, the probe would have the initiative. If it can communicate, and has a sufficiently advanced artificial intelligence, then we'd be very interested in what it had to say; if it was damaged, then all we could do would be to analyze it. If it said it would only talk to the UN, we probably wouldn't argue. There would be a conflict between quarantining it (it could have extraterrestrial bacteria, or it could have become radioactive, etc.) and displaying to the media, given that there would be a natural skepticism about the discovery, especially if it had not previously be detected moving through our solar system. If it appeared in US territory, given that the US has the resources to examine it, they would probably handle it through military channels (because there could be a legitimate worry that it would be dangerous). A cover-up would probably be impossible. Peter Grey 17:59, 5 September 2006 (UTC)

Is it really a good idea to carry the probe away immediately? The aliens who sent it don't even know there's life on Earth, and if somebody takes the probe away, they'll think their mission failed.

I picked the U.S. as the landing place because its people know (relatively) a lot about science. If I picked some small community in Africa, where half of the residents are illiterate, they'll think it's a gift from God or something. And no, this is not a question about U.S. politics. It's about how we should let the aliens know that life exists on Earth. --Bowlhover 03:39, 6 September 2006 (UTC)

Why are you assuming the alien probe lets itself be confiscated and examined? --Proficient 03:46, 6 September 2006 (UTC)

If a probe lands in a an inhabited area with artificial structures, it is probably not trying to go undetected. Of course, maybe it's builders just think differently. Peter Grey 13:24, 6 September 2006 (UTC)

Kurt, the pope? He'd certainly hush it up. What are the chances the aliens are catholic? And what would the catholics make of that?

Why do these things always land in the US in hollywood movies? It has only 2% of the Earth's surface. Then again, the martians in War of the worlds landed in England, which even has less than a promille of the surface. A Luxemburgian SciFi writer would have a serious credibility problem. :) DirkvdM 17:50, 6 September 2006 (UTC)

You seem to be assuming they just land somewhere at random (and you even include landing on water, apparently). What if they have been observing us and decide to land in the "center of power". They might well decide that is the US now, or England back in H. G. Wells' day. StuRat 09:53, 7 September 2006 (UTC)

If conquering the Earth is the goal (as was teh case in War of the Worlds) then it wouldn't be smart to land in the lion's den. Especially if that lion is armed to the teeth. Landing on an ocean would make most sense if the goal is to establish a base first. The oceans are barely observed (a problem for meteorologists) and one can go underwater for even better cover. But even if they don't know how to build (u)boats and have to land on ... ehm ... land, a remote piece of land would make a better choice. Like Siberia or the Sahara. The US has some deserts too, but is the most paranoid country on Earth when it comes to attacks (with reason, but that's a different issue), si that would be the most likely place to be detected. So, to come back to the original question, if aliens land in the US they are either incredibly stupid or want to be detected. DirkvdM 18:50, 7 September 2006 (UTC)

separation of chemical compounds

How could you separate barium sulfate from ammonium chloride?

How could you separate barium chloride from calcium sulfate?

How could you separate tellurium dioxide from silicon dioxide?

Undesguised homework again? Choose some of the properties and use the most appropriate ones to aid separation.--Light current 02:00, 5 September 2006 (UTC)

i'm guessing reading isn't his/her strong point... Xcomradex 03:03, 5 September 2006 (UTC)

Mine neither--Light current 05:30, 5 September 2006 (UTC)

no for you it's spelling, unless it's all a clever desguise... ;-) (no harm intended). Xcomradex 08:07, 5 September 2006 (UTC)

I prefer to call it finger trouble! THe keys are too close on my keyboard 8-)--Light current 08:24, 5 September 2006 (UTC)

• Salts like the ones you describe are usually separated using precipitation reactions. You need to figure out the rest. - Mgm|^(talk) 10:53, 5 September 2006 (UTC)

Sulfates of the Alkaline Earth elements are generally insoluble in water. Chlorides are usually very soluble in water. I do not have a clue about the last one, both are very insoluble in water, but maybe a solvent exists which is good for one but not the other.

For the third pair, one of them is twice as dense as than the other. See Silicon dioxide and Tellurium dioxide. Of course, I'd use a mortar and pestle and my firing oven, but that's just me... -- Fuzzyeric 00:06, 6 September 2006 (UTC)

California Moss Genus/Species

Can someone tell me the taxonomical binomial nomenclature of that common, general greenish moss that is found all over rocks and such on the southern West Coast? Thanks so much, ChowderInopa 01:58, 5 September 2006 (UTC)

You mean what its called?--Light current 02:04, 5 September 2006 (UTC)

Yes, I mean the scientific name. ChowderInopa 02:38, 5 September 2006 (UTC)

Can you say something more about its appearance? Are these damp habitats? Are you sure it is not lichen? --Lambiam^Talk 07:59, 5 September 2006 (UTC)

The southern west coast of what? Oops, missed the header. DirkvdM 09:09, 5 September 2006 (UTC)

satellite imagery maps

I need to know where to look for the satellite imagery maps. I want to see what my home looks like from above and the locations around my home. Please show me how to get there on wikipedia. Floyd — Preceding unsigned comment added by 68.119.96.36 (talk • contribs)

I'm too tired to do the whole 'build a satellite' launcher routine, fun as it would be. Google is your friend. Go there, and punch in your ZIP/postcode. If necessary, switch from map to satellite view. --Mnemeson 02:21, 5 September 2006 (UTC)

for even more google, try Google Earth. its great. Xcomradex 03:05, 5 September 2006 (UTC)

Do you smell burning toast?

Hey, could anyone settle a debate for me? My friend doesn't believe that smelling burnt toast, when there is no environmental source of the smell, could be a sign of a stroke. Is it a common occurrence, something that happens rarely, or just a myth? Thanks in advance for your input. --Dimblethum 02:52, 5 September 2006 (UTC)

It could be a sign that you suffered a stroke, and then tried to toast the same slice of bread 10 times, after which it would smell rather burnt. :-) StuRat 03:02, 5 September 2006 (UTC)

It may be a symptom of a stroke. (See for example this case study.) It may also be indicative of a brain tumour (it is sometimes a sign of brain metastases in advanced cancer), or of some neurological problem, or it could just be a passing random olfactory hallucination. An odour of 'strawberries' is also reported by some individuals. Some people have also reported a burnt toast smell immediately before a seizure or migraine. TenOfAllTrades(talk) 03:04, 5 September 2006 (UTC)

Burning rubber is another one. George Gershwin had this symptom before they diagnosed his brain tumour. Any disturbance to the proper functioning of the brain can produce visual, auditory, olfactory, gustatory, or kinesthetic perceptions of external phenomena that do not objectively exist. JackofOz 07:13, 5 September 2006 (UTC)

So are synesthetics in constant threat of a stroke? DirkvdM 09:19, 5 September 2006 (UTC)

I think you can work that one out yourself, Dirk. JackofOz 12:04, 5 September 2006 (UTC)

burnt toast

I've heard that burnt toast has the same calories as regular toast. I believe it has less, but negligably less compared to our caloric intake.

what are th e facts?

Jasbutal 03:52, 5 September 2006 (UTC)

That sounds reasonable, but I have no facts. I would guess that if a piece of burnt toast is still palatable enough to swallow, then it can't be too badly burnt after all, and its interior is still perfectly nutritious. Melchoir 03:58, 5 September 2006 (UTC)

I dont see how it can have the same, since some of the bread has been reduced to pure carbon. THat is how you tell the calorific value of food- you burn it in pure oxygen till theres only ash Food_energy#Measuring_food_energy.--Light current 05:09, 5 September 2006 (UTC)

I'd say both statements are probably correct; there isn't necessarily any contradiction between "(approximately) same" and "negligibly less". (Or course, that depends on how burned the toast is — if you burn it all the way down to water, carbon dioxide and ash, it won't have any caloric value left.) —Ilmari Karonen (talk) 05:23, 5 September 2006 (UTC)

Exactly. So how many calories would you like in your toast this morning Sir?--Light current 05:27, 5 September 2006 (UTC)

As dry as it may seem, regular toast still contains a considerable amount of water. The overheating that causes the toast to burn also evaporates some of the water. The net effect on the calories per unit weight may initially be an increase. --Lambiam^Talk 07:51, 5 September 2006 (UTC)

Yes that is why toast racks are used I believe- to let the toast dry out and not go all soggy.--Light current 08:10, 5 September 2006 (UTC)

Very interesting. --Proficient 03:48, 6 September 2006 (UTC)

Blindness and circadian rhythm

I recall reading about an experiment where some college students were locked in a windowless suite of rooms without a clock, and were invited to sleep whenever they wished. Many of them began sleeping at unusual times that wouldn't map well to the 24-hour day. However, when they were made aware of the sun's progress, their sleeping patterns began to approximate the day-night cycle. Is anyone else aware of this study? My question is this: do the sleeping habits of blind people tend to be independent of the sun? Presumably the only non-visual distinction between day and night would be one of temperature, and if the person remained inside in a climate-controlled environment, this would not matter. Long question short, is there any record of blind people having trouble casually (i.e. without having to put special effort into it) distinguishing night from day, and experiencing sleeping problems as a result? Is it plausible? I'm not talking about people with jobs and schedules, but people who might not pay close attention to clocks, such as people in hospitals or retirement homes. Bhumiya (said/done) 05:00, 5 September 2006 (UTC)

I don't believe your assumption that blind people are less aware of the time of day is correct. They have a variety of ways to check the time, from audio watches, to radio and TV broadcasts, to periodic events, like church bells ringing, etc. While it's true that a blind person in a coma in a hospital would be unaware of the passage of time, the same is also true of a sighted person in a coma. StuRat 07:12, 5 September 2006 (UTC)

Well, that's true, but I didn't mention comas. I only meant patients in general, who would have little to do but lie in bed. Bhumiya (said/done) 03:56, 6 September 2006 (UTC)

I believe that a blind person, in any condition short of a coma, would still be aware of the approximate time of day. StuRat 06:44, 7 September 2006 (UTC)

Years ago I remember seeing a tv doc about people living in windowless rooms without any time cues. They started to live on a 25 hour cycle, which curiously enough is the same length of day as on MARS!!

I think blind people would take their cues from tv, radio, alarm clocks, and other people.

But I think the intresting question is whether you can force your body to physiologically adapt to an arbitrary night/day cycle without the usual help you get from light, which causes your brain to secrete a variety of transmitters that entrain your circadian rhythm. I guess it would depend on what the exact cause of the blindness is. Nrets 16:56, 5 September 2006 (UTC)

I think that if anyone is not aware of the sun's changing, then they will have an internal clock that keeps changing and getting off. --Proficient 03:50, 6 September 2006 (UTC)

I once heard or read, but cannot confirm, that there are two common circadian patterns among humans, one of which is about 25 hours long, the other 32 hours or something like that. Bhumiya (said/done) 03:56, 6 September 2006 (UTC)

I remember hearing, but I also can't remember where, about recent research suggesting that there was some kind of problem with the research that came up with the 25 hour figure, and that more recent research suggests that the free-running cycle in humans is closer to 24 hours. (Our article on circadian rhythm sure needs work. We also have an article on Free-running sleep, but it seems to use the term to mean sleep that's unaffected by artificial rhythms, while in biology I think "free-running" refers to rhythms unaffected by anything external to the organism, natural or not.) --Allen 04:15, 6 September 2006 (UTC)

I think that we may be proceeding with a false assumption. I also remember hearing, from at least two sources, that the effect of light affecting circadian rythm is not purely visual. The effect of light upon one's skin can also serve as a cue. Even a blind person would have light shining on his/her skin, and this would seem to be an additional cue as to whether it's daytime or nighttime. Loomis 12:46, 7 September 2006 (UTC)

Mantle

Has there ever been an attempt at diging down through the crust to reach the mantle?

Yes I think it was called the Mohole project.--Light current 05:29, 5 September 2006 (UTC)

...which failed. The Japanese are going to have another go at this next year. See Chikyu Hakken.--Shantavira 06:06, 5 September 2006 (UTC)

At the risk of asking a silly question, wouldn't that cause magma to rise and cause a volcano? I suppose one would have to make sure to drill at the right spot, where the is no magma chamber. Did I just answer my own question? DirkvdM 09:32, 5 September 2006 (UTC)

If you'll forgive me for attempting to answer a question that I myself was about to ask: I believe any area that would be in danger of spurting would be doing so already, or at least would be showing some sort of bulge. Any low/thin area of sea bed should conceivably be on top of a relatively inactive section of magma.  freshofftheufoΓΛĿЌ  13:38, 5 September 2006 (UTC)

And yes, I guess you did ^_^  freshofftheufoΓΛĿЌ  13:40, 5 September 2006 (UTC)

Awesome.

At the risk of accusation of adding rubbish comments, I would say I tend to agree with the bulging hypothesis--Light current 00:03, 6 September 2006 (UTC).

Ah, so that explains the eruptions. This the kind of rubbish comment you were talking about? DirkvdM 09:21, 6 September 2006 (UTC)

Small writing - should it be allowed?

Hmmm, I now realise you may not have been thinking about the bulging and eruptions I was thinking of .... DirkvdM 19:16, 6 September 2006 (UTC)

Yeah man, that was pretty embarrasing. Maybe if you delete it now, no one will notice.  freshofftheufoΓΛĿЌ  14:13, 7 September 2006 (UTC)

Or maybe if I make myself really really small ... can't get it smaller than 0, though. DirkvdM 18:55, 7 September 2006 (UTC)

Psst! do you think you will go unnoticed by writng this small? Some people here have eagle eyes you know!

Damn, someone gave this a really big header. We'll be spotted any moment now. DirkvdM 06:55, 8 September 2006 (UTC)

Yeah but this is a legitimate discussion of the use of small writing on the Ref desks. And it takes up less room than big writing.--Light current 07:04, 8 September 2006 (UTC)

Is it Bad to run PC without proper Earth supply?

Hi friends!...I've been using pc for a couple of years without supplying earth because in our block we have no earth connection to ground...Now is it ok to proceed so or need to give earth?..however I can feel some earth(mild current shock) passing on me whenever I touch the metal parts in the PC because of no earth..I know why this is,because of the returning current has no path way to ground an hence circulating in the cabinet and in all the metal parts..Some say it will affect HDD or RAM soon...Is it so?..and is it okay to proceed as usual?...or should I take immediate action for earthing?.But until now I haven't gotten any faults in my PC...Please help friends...My advance thanks

I'd say if you are feeling any shock at all, then yes, the computer should be grounded, immediately. (It's also a good idea, in any case.) :-) StuRat 07:06, 5 September 2006 (UTC)

Do you mean you should be grounded? What naughty things have you been upto this time? DirkvdM 09:36, 5 September 2006 (UTC)

"One should be grounded in reality" ... you ought to try it sometime ! :-) StuRat 01:58, 6 September 2006 (UTC)

If you have an external AC adapter, you should not be in danger of a serious shock, as it only delivers a low voltage (say 16V) to your PC. With an internal power supply, you might get electrocuted, which is generally not recommended. You could use a voltage meter to check if any metal parts carry an unsafe voltage compared to ground. --Lambiam^Talk 07:34, 5 September 2006 (UTC)

Thanks...I recieve some mild shock inside the PC only...Maximum voltage of the SMPS (Internal Power Supply output only) is 12V.So I guess there shouldn't be risk of high volage shock..but say the current rating is as high as 22A..The shock is mild only which is bearable though..My suspect is that if it's gonna affect my hardware parts?...I haven't recieved any complaints yet since from the time I bought I've been using without earthing...

Unless this equipment is double insulated (which I doubt, if it has a metal case), it is not only undesirable, it is downright dangerous and even LETHAL. THe fact you are getting shocks should tell you this. Switch off NOW, unplug from the socket, and contact a reliable electricain immediately!--Light current 08:05, 5 September 2006 (UTC)

Isn't that last advise a bit over the top? I've connected my computer case to an unpainted part of a radiator. Shouldn't that suffice? DirkvdM 09:36, 5 September 2006 (UTC)

No I dont think so. The BS regualtions state that Any Class 1 equpt should have all exposed conductive materials solidly earthed to the mains earth. Furthermore, there is a requirment that the loop resitance of live and earth shall be less than a certain amount so that the protective device is activated. --Light current 13:22, 5 September 2006 (UTC)

The equipment is double insulated (wire casing and psu casing) until it gets to the PSU and after that the voltage and current are whacked down from hairburning to finger tickling levels. so... people should be alright. Philc _T^E_C^I 10:44, 5 September 2006 (UTC)

In the UK I'm sure it would be illegal to have an electricity supply without an earth. But in America......

Still though, most household items dont have an earth, only ones with metal casing do, often they dont even have an earth pin, just a dud plastic one. Philc _T^E_C^I 10:44, 5 September 2006 (UTC)

I thing no one here has grasped exactly what I meant.I told you that the shock is not severe at all and it's just a leakage current due to the absence of proper earthing....The shock is bearable only...This shock wasn't observed when I checked it with my friend's house(He has earth in his house)since the PC operates with only 12V,how can it be so lethal and dangerous?..The cause why I recieve shock should be b'coz of leakage current circulating over the panels....It's seems no threat to humans though I suspect if it can be for the Hardware in my PC...If I touch the RAM,HDD it gives me this mild shock still...I really wonder when it will die hard...

This is stray voltage, as in this ref [19] It is very bad for cows. For people, it is not that good, especially if one day you are touching the case, and the water tap at the same time. You could put on a Residual-current device, or attempt to ground with a pipe. Most likely, there is a short in the computer that will limit its life. --Zeizmic 12:28, 5 September 2006 (UTC)

If youre feeling anything, it means that electric current is flowing from your computer metalwork through your bod and down to earth. THis means that the casing is live and dangerous. I advise you get it looked at! It really sounds as if this eqpt needsan earth. Check the handbook!

THe danger comes from the fact that mains voltages are entering the power supply. If the power supply is faulty, the case can become live. If the case is not earthed, protective devices (fuses, breakers) will not operate and you are in danger of ELECTROCUTION! Please take it from me. I have experience in this field.--Light current 13:31, 5 September 2006 (UTC)

The usual phenomenon with lots of big SMPSs is that there's a big RFI filter right at the mains power input; the filter blocks both RFI coming into the supply from the line and power supply hash going back out onto the power line. This filter usually takes the form of an LC "pi" filter on both the neutral (return) and hot (live) lines, usually with pretty substantial capacitors to the safety ground which, of course, is then connected to the chassis of the SMPS and whatever the SMPS itself is then bolted to. If the safety ground lead isn't so hot or is outright disconnected, you find that the capacitors make a voltage divider that puts the chassis at about 50% of the line (mains) voltage, and most people can definitely feel that ;-). Whether or not it's enough current to cause a hazard depends on the design of the specific power supply, but I think that regulatory agencies won't permit such large capacitors in the pi filters as to allow a dangerous amount of leakage for ordinary equippment that is expected to be used in a residential or office environment.

At Digital Equipment Corporation (my former employer), because our high-current pi filters had larger capacitors, we had to put warning labels on the power cords of our big commercial equipment warning folks that there was enough leakage capacitance that the safety ground had to be connected to earth; otherwise, unsafe amounts of AC leakage current would occur.

So that's one aspect of the problem: ordinary operation. Then there's the question of the various faults that can occur. I'm in complete agreement with the folks above that because certain faults could possibly lead to mains power being connected to the chassis, it's essential that things that have a safety ground pin on their line cord (mains flex) either be connected to an actual safety ground or be connected to the mains through a residual-current device (ground fault circuit interrupter/GFCI). Those two methods are the only way to assure your safety if a worst-case fault occurs in the power supply.

And then, of course, there's the question of electrostatic discharge and your computer's ability to resist that. Absent an intended safety ground, you may find that your computer isn't able to resist static discharge (for example, sparks from you) to the degree that you would have expected. But that only endangers your data and your computer, not you.

Atlant 00:03, 6 September 2006 (UTC)

Dont forget, Atlant, that we dont know the line voltage at this users house. If its only 120V ac and it is a line RFI filter thing, then he gets 60 vac to ground. However in countries with 240 vac, the volts are definately 'feelable'. The current limiting of course depends upon the capacitor reactance. I had this very problem with an intermittent earth wire (inside the scope case) on a 485 Tek scope - wondered what the hell was going on!--Light current 00:22, 6 September 2006 (UTC)

Where do you live, where your entire block isn't electrically grounded?! That floating city from Star Trek? Clarityfiend 04:18, 6 September 2006 (UTC)

In the US it would be very strange for the whole block to share an earth ground. Each house should have its own 8 foot (or so) copper rod driven into the ground to provide earth ground. Failing that, you should be able to tie the ground wire of the electrical system to a cold water pipe. Of course if the electrical is old enough, there won't be a ground wire run to every outlet, but its easy enough to ground any new circuits you install. -- 69.106.48.1 05:00, 6 September 2006 (UTC)

(Off on a tangent...) In the US, you actually do share earth grounds. Ordinary household split phase utility distribution systems are usually constructed with a grounded neutral, grounded at many points including every distribution step-down transformer. Then, the neutral is grounded one more time at your house's service entrance. All this redendancy of grounding helps assure that the neutral really does stay within a very few volts of the true earth ground potential.

Atlant 23:56, 6 September 2006 (UTC)

Make sure electrical modifications are done by a qualified electrician. The ground wire for any new socket must run from the circuit breaker panel or fuse box. It is improper to go around connecting the ground terminal of an outlet to any random cold water pipe near the outlet. One reason for this is that the circuit impedance may be too high to pop a circuit breaker quickly to prevent electricution. The impedance is lower when the ground return is in the same cable as the outgoing hot wire, and higher when it travels a different path. Also the pipe you connect to may be isolated from the main ground by a dielectric fitting, and so a phase to ground short in an appliance would only energize say your bathroom faucet, creating a new shock hazard. Edison 15:06, 6 September 2006 (UTC)

Memory and aging

Can you please find me information about Barnes' 1997 experiment with rats. he tested how the rat's age affected memory.

thank you.

Google is your friend. Just search for your key terms such as: Barnes 1997 experiment rats memory. Dismas|^(talk) 07:44, 5 September 2006 (UTC)

you won't have luck with rats around here, there are no experts. but if you were to ask about barnes's earlier experiments with seagulls... Xcomradex 08:11, 5 September 2006 (UTC)

ARRRGH--Light current 08:26, 5 September 2006 (UTC)

No expert on rats ? That's not fair ! StuRat 23:16, 5 September 2006 (UTC)

Phloretin, phloridzin

According to the literature, both of these chemicals seem to inhibit glucose transport into cells. -idzin has a glucose molecule attached, where -etin is exactly the same molecule, just missing this glucose moiety. Does anyone have any insight into why this is, as it's quite counter-intuitive. I would expect -idzin to be an "invincible substrate" kind of thing, but then how does -etin work?

Thank you very much Aaadddaaammm 09:04, 5 September 2006 (UTC)

i guess it shows you the aglycone of phloretin is active piece, not the glucose bit. phloretin is a protein kinase C inhibitor, as well as an inhibitor of a number of transporters, including the glucose transporters. so that's where the effect comes form, it's just coincidence phloridzin has glucose on it. [20]. Xcomradex 10:18, 5 September 2006 (UTC)

How processors work ?

How the control unit of a CPU/PROCESSOR/MICROPROCESSOR works ? I've cearch in wikipedia and in other sites but they all provide me the information that microprocessors are made of transistors ; several electronic gates like and,or,not are described . But i want to know the process by which microprocessors control an electronic device using 0&1 as input . How transistors are placed in a microprocessor ? How the increasing number of transistor in a processor increase the processing speed of a microprocessor ? What's the minimum number of transistor that can form a microprocessor (it will be better if a circuit is drawn showing positions of transistors and explanation of where the circuit takes input and where the output)? Explain the working procedure of microprocessor by an example of mp3 player .

Does the above question sound like a homework assignment? Explain your answer with reference to the above text :PPikiwedian 09:52, 5 September 2006 (UTC)

The information is all in Wikipedia. I doubt whether anyone is going to give you a succinct answer to all your questions here as they involve several different disciplines. Have you looked at transistor, digital circuit, logic gate, and microprocessor? --Shantavira 10:28, 5 September 2006 (UTC)

CPUs may be made out of logic gates, but that's like saying DNA is made out of atoms. It's not an explanation.

Here's a popular question: "Where is the little man who actually does the work?" Often that little guy is a binary counter which can turns on various output lines depending on the current count. The "little man" can also be a ROM and a parallel latch, where the data bits from the ROM are held in the latch and sent back to the ROM's address lines. In any case, the 'brain' of the CPU is a state machine. You may be more familiar with a common state-machine everyone uses: the dial on a washing machine. In fact, it should be possible to use an old washing machine dial as the central mechanism in a very crude electromechanical computer. (First thing to do would be to change the gearing so that the dial can be rotated fairly rapidly!) --Wjbeaty 20:03, 6 September 2006 (UTC)

Yes,though most of us know it better,we can't keep typing everything in here.It's practically impossible..My suggestion is to have a good book knowledge first....But we can give some basics what we can....First you must know the internal architechure of any basics Microporcessor atleast like 8085,8086 (x86 series basics is good).Try google search for the architechure 1st.It's quite easy to learn...Your question is multi-directional and it confuses me where to begin with...I'll drop some basics that should be useful...later check the Wikipedia or in google, in detail for learning about transistors in digital circuit and logic circuits that control devices as Shantavira said. 1)Any control unit uses multiplexers(MUX) and DMUX to send signals to the multiple periperals with reduced pins in IC.This helps in reducing the CPU size...These are usually done with the aid of gate combinations eg.,NAND or XOR etc....So to enable a peripheral,all it needs to send is a low or high signal like(READ or WRITE or READY or ACKN or etc)which is an information that can be obtained from reading the instruction stored in RAM with respect to the CPU clock.It has Address Bus and Data Bus inside...Upon executing each instruction step by step,your CPU(Program Counter\Stepper)places the next intruction address and starts fetchin the data from RAM.This process keeps on cycling according to your program....Upon this,instruction is something which has information about the operation type and the Data for that operation written in Machine Language.This is depicted as opcode(operation type) and operand(operation Data) which is a standard format of any instruction. For eg.,

      "INSTRUCTION = (OPCODE+OPERAND)"
                   =    "OUT FFh".

Here Out is the OPCODE and FFh is the peripheral address.The data to be sent to this device is stored in one of the data registers.Each instruction is stored in different address in your RAM.So All you gotta do is to write your desire instructions and then store it in RAM and begin executing..There you go.....Here The opcode tells the CPU to send the data in it's default register to the device which is in the address 0xff location....Upon executing this instruction,the CPU 1st reads the Opcode only in it's first clock cycle and then it understands the meaning of that operation and it generates control signal accordingly and clears the pathway to this address and sends the data by reading the Operand in its next clock cycle.By decoding opcode,CPU can determine it's action and it generates the control signal...Provided the CPU has many supporting registers(unit for storing data) for ALU operation....so it can store frequent data up there and refer to it..Note it's only the instruction of your program that makes the CPU to geneate control signals...Your electronic device when connceted to CPU,automatically it must be given as address so that it can be identified uniquely like IP address...as we looked the instructions,just choose the appropriate insturction for controlling the device....For more and detailed information about the generation of control signals,please check out your text books... 2)About the transistors,the ON and OFF state is the only means by which we can store any data digitally.perhaps if one transistor is required for just storing one bit(0 or 1),then 8 transistors are required for 8-bit and so on..Technically they no longer call it as 8 transistor,but simply as Register and they give names like reg A or reg EA or so on....So a 32 bit CPU like any pentium processors has registers of 32-bit lengh,but it can have 16 or 8 bit units still...More the amount of registers,more number of intructions can be executed and stored and hence maintaining parallelism....so more number of transistor,more powerful and faster your CPU is. 3)Since 4004 is the 1st microporcessor(to my knowledge) which just had about 2300 transistors with operating clock of 108 KhHz...It's only a 4-bit processor(Data bus only) compared to any 32/64 bit processor now...So I guess atleast 2300 number of transistors might be required for making a CPU with reduced size(I'm not though sure) 4)Similarly for playing music CD's there are always some default instructions which are stored in your player's memory permanant.They are nothing other than the one that tells your procesor about seeking the CD with spin up and spin down command and also how to control the laser movement in readind the CD directory..You can learn more about this by experimenting with Microprocessor controlled Stepper motor.Once locked to the track in the disc,it keeps the trace and starts moving horizontally hence giving the data(music) from the pits....Apart from this,all user interfaces(Buttons,LCD,etc) are all controlled by microporcessor(Microcontroller is used these days instead) only...Regarding MP3 or other formats of audio,comp/decomp and all kinda processing is done by DSPs only...Besides these there are lot to know....I hope this Basics should help somehow..(Correct me if I'm wrong)

You may also want to read [21] and subpages. (You probably need some knowledge of informatics or electric engineering to understand that.) – b_jonas 21:38, 5 September 2006 (UTC)

Smelling things that aren't there

Ever since high school I have had periods of time where I would occasionally smell what I can most closely call cigarette smoke (although not quite). The whole thing seems to be psychological and fairly random (I'm not sure of any specific triggers), I can go months at a time without smelling it. and I have a friend who has had a similar phenomenon since her uncle died of lung cancer. Strangely enough, another friend has the same situation but with "hospital smell." I don't like cigarette smell and the latter friend doesn't like the smell of hospitals. Is there a term for this? Am I going to die? AEuSoes1 10:03, 5 September 2006 (UTC)

• Well, I doubt you're dying, but according to Wikipedia:Reference_desk/Science#Do you smell burning toast? it might be a symptom of a stroke. I don't know what smelling things without a source is called, but if you worry about dying, you should see your doctor about it. - Mgm|^(talk) 10:50, 5 September 2006 (UTC)

That's what made me think of this, but I'm not smelling it constantly, which the case study stated. According to the page on strokes I (a 24 year-old in fit health) am not really at risk for a stroke. AEuSoes1 11:23, 5 September 2006 (UTC)

Some more information and links can be found under hallucinations and olfaction. There's also an unreferenced stub article on phantosmia. If you're worried, please go see a doctor. We cannot give medical advice at the reference desk. ---Sluzzelin 12:19, 5 September 2006 (UTC)

Is it possible you're actually around people who are smoking? Maybe they're smoking something close to cigarette smoke.--152.163.100.74 12:33, 5 September 2006 (UTC)

Intermittent smells can also be a sign of an impending seizure or migraine. See aura. Not common, but certainly possible. InvictaHOG 20:40, 5 September 2006 (UTC)

The whole "am I going to die" part was actually a joke. I've already been to a doctor about this and he thought it might be an allergy to something (if it walks like a duck...). Thanks for the info. AEuSoes1 21:02, 5 September 2006 (UTC)

Plane speed

If a plane is flying east to west, does it travel faster relative to the ground because of the spin of the earth? Or does the fact that the air it is in also spins cancel that out? Richard Bladen 13:24, 5 September 2006 (UTC)

The latter. Consider that at the equator the rotational speed of the Earth is over 1000 miles per hour, faster than the cruising speed of virtually all aircraft. However, US->Europe flights are usually of shorter duration than Europe->US flights due to prevalent winds. — Lomn | Talk 14:44, 5 September 2006 (UTC)

And for planes that get into the jet stream, the difference in speed is even more dramatic. Planes routinely use both ground speed and air speed to measure their velocity. StuRat 23:10, 5 September 2006 (UTC)

Thanks a lot Richard Bladen 00:25, 7 September 2006 (UTC)

Keep your bowels fit?

Will your bowels deteriorate if they don't get anything to "work" with, food for instance? I was just wondering, if a person's nutritious requirements were met simply by eating a capsule the size of a walnut once a day (very futuristic), leaving the bowels inactive for most of the day, would the bowels stop working/deteriorate in function? Jack Daw 13:37, 5 September 2006 (UTC)

Your body would still need to dispose of bile and dead blood cells - the stuff that makes your poop green or brown (depending on which is in excess). So, even without food, your bowels would continue pushing "stuff" through. I think the real "victim" would be the population of bacteria in your bowels waiting for something good to eat. --Kainaw ^(talk) 13:55, 5 September 2006 (UTC)

So what about the bacteria then? What would happened to them, and how would that affect us? Jack Daw 14:27, 5 September 2006 (UTC)

The bacteria are part of your immune system. Without them, any foreign bacteria that make it to your gut will have an easier time causing disease. Of course, since you're not eating much, fewer foreign bacteria will make it to the gut in the first place. --Serie 22:41, 6 September 2006 (UTC)

I'm actually not sure anybody knows the answer to this, since such a diet does not yet exist. Some information may be gleaned from victims of malnutrition, but the malnutrition itself confounds the observation. In other words, it may not be clear whether a particular intestinal symptom is due to lack of activity in the bowel or to lack of nutrition for the cells. See below. --Ginkgo100 ^{talk · e@} 20:20, 5 September 2006 (UTC)

Actually, the bowel begins to decondition shortly after a person stops eating/drinking. This happens a lot in the ICU setting. As for bypassing the bowel entirely, we don't need pills. We actually routinely completely bypass the bowel by using total parenteral nutrition, which is basically food through the veins. There are people who have lived decades without eating. InvictaHOG 20:42, 5 September 2006 (UTC)

So, yes, the bowels will deteriorate without food, perhaps to the point where they become completely unusable, forcing the victim to live the rest of their life getting all their nutrition via an IV. Not a pleasant prospect. StuRat 23:05, 5 September 2006 (UTC)

I believe this is an issue for astronaut food - the bowels need something to work on, so just pill food won't do. Strangely I can't find anything on that in Wikipedia. DirkvdM 09:26, 6 September 2006 (UTC)

Oh, I should have thought of that. *smacks head* Of course there are ways to provide nutrition besides through the gut. --Ginkgo100 ^{talk · e@} 22:05, 6 September 2006 (UTC)

How does retinol kill?

The retinol article says that retinol can kill you, but How? It doesn't say. Anyone's got an answer?

The liver eventually can't store any more retinoids and they enter the blood stream causing a strong and dangerous immunological response called sepsis. See also hypervitaminosis A.---Sluzzelin 14:20, 5 September 2006 (UTC)

I see. And why does increased serum retinol cause sepsis? Jack Daw 14:26, 5 September 2006 (UTC)

On a similar subject, said article also states that: "The livers of certain animals, especially those adapted to polar environments, often contain amounts of vitamin A that would be toxic to humans." Why do polar animals have greater hepatic concentrations of retinol? I suppose it helps them in some way, but how? Jack Daw 13:42, 5 September 2006 (UTC)

Due to the scarcity of vegetable food, arctic super-predators, such as polar bears, eat a lot of other animals who are also predators. Organic compounds tend to accumulate up the food pyramid. See biomagnification. Higher hepatic concentration of retinol doesn't help the animals directly, some of them have just adapted greater storage capacity for organic compounds, thus avoiding sepsis. ---Sluzzelin 14:20, 5 September 2006 (UTC)

Naturally. Thank you. DS

request for location of manuals and papers

Can somebody say me a good website to find detailed and illustrated manuals and papers on any of the following topics : neural network, artificial intelligence, power electronics, power quality, robotics, VLSI, HVDC transmission and electronic topics? thank you for your help.

Start by searching for the terms in Wikipedia, and reading the articles you find. Then read the references in the Wikipedia articles. Then Google the terms and read the websites you find. Then go to a public library and ask the reference librarian to help you find books and magazines on the topics of greatest interest. Edison 20:19, 5 September 2006 (UTC)

Edison made some good points. --Proficient 04:05, 6 September 2006 (UTC)

backlog?

Has it ever occured to anyone how much Backlog sounds like B'log? Blog? Backlog? What are the scientific chances that 2 unrelated words would sound so similar--152.163.100.74 14:15, 5 September 2006 (UTC)

This is a rather vague question. Anyway, the words are related -- quite closely. They're two compound words both using "log" plus a leading descriptor. As for sounding alike... I find that it's fairly hard to confuse a two-syllable word with a one-syllable word, particularly when the extra syllable is the stressed one. However, languages generally reuse bits of sound (check the Language desk for better explanations). For example, a word starting with "str" is scientifically unlikely if you just generate character strings, but it's easy to think of a great many English words satisfying the condition. — Lomn | Talk 14:56, 5 September 2006 (UTC)

They're called homophones. JackofOz 00:09, 6 September 2006 (UTC)

I see where you're coming from, but I don't quite agree that they sound so similar. --Proficient 04:06, 6 September 2006 (UTC)

hahahah what ar ethe scientific chances?!?? omg I love the hubris and faith on this site. I...um...calculated it using computational linguistics. The chance is 1/15212. Jasbutal 04:42, 6 September 2006 (UTC)

I recall reading somewhere that there is a tendency for homonymy in languages. Probably has something to do with needing to remember less words with more definitions.

Gourami identification needed

Some type of gourami, sold to me as simply a "golden gourami"

I need help identifying which species is in this picture. I own the fish, but I never bothered to ask what species it is. The image is currently on Trichogaster trichopterus because it mentions "golden" varieties, but I'm not sure if that's right (the markings look different). Help would be greatly appreciated. --Pharaoh Hound (talk) 14:59, 5 September 2006 (UTC)

It is a golden variety of blue gourami (Trichogaster trichopterus) as you thought. --Ginkgo100 ^{talk · e@} 20:08, 5 September 2006 (UTC)

Thanks! (sorry I didn't answer sooner, the server was locked for maintenence when I tried yesterday) --Pharaoh Hound (talk) 12:43, 6 September 2006 (UTC)

Simple Law of Motion Question

Simply stated, in a practical application, would a ball dropped in a moving train fall directly down, or would it experience some movement towards the back of the train (assuming the train is moving at a constant speed)?

From the pov of someone in the same carriage, the ball would appear to drop vertically to th e floor. From the point of view of someone watching from the trackside, the ball would appear to travel in a parabolic trajectory.--Light current 15:16, 5 September 2006 (UTC)

[Edit conflict] (Assuming the train and ball are already travelling at a constant velocity) To a person on the train, the ball falls straight down. To a person obseving from outside the train, the ball falls both down (accelerating at one g) at forward (at the velocity of the train). Raul654 15:17, 5 September 2006 (UTC)

Should your train for any reason at all be situated in space, the ball, once dropped, should move alongside you without much trouble at all. :) 81.93.102.45 16:55, 5 September 2006 (UTC)

It is accelaration that would cause the ball to fall in a curved path relative to the train, not velocity, assuming the carridge is a sealed capsule, (i.e. if your on a flat bed, the wind would blow it back). Philc _T^E_C^I 20:10, 5 September 2006 (UTC)

There's always a caveat, so just to ruin the party: if the traincar in question has a lot of open windows, the resulting draft would push the ball towards the back of the train. Melchoir 20:17, 5 September 2006 (UTC)

Also, the ball would only fall straight down if the train is moving at constant speed in a straight direction. StuRat 22:50, 5 September 2006 (UTC)

If windows are open, the air current can go in many directions, depending on where you are located. Often, right next to a window, there may actually be a strong forward wind. (btw, is the similarity between 'wind' and 'window' purely coincidental?) DirkvdM 09:31, 6 September 2006 (UTC)

Wiktionary claims it isn't, it's actually derived from wind. And there's also "windscreen". – b_jonas 12:14, 6 September 2006 (UTC)

Ha! Another thing I make up that turns out to be true. It's a good thing I make up most of the things I say. That way there's a good chance I get it right. :) DirkvdM 17:54, 6 September 2006 (UTC)

Strange insect identification

Unknown insect

Hello, can anybody help me identify this strange insect I found in my garden? Thanks in advance. Davide125

Froghopper? It looks like the insects that come out of cuckoo spit in my garden, and cuckoo spit redirects to that page. Skittle 17:23, 5 September 2006 (UTC)

Froghoppers are rather small. How big is this critter? Also it might help to know which country your garden is in.--Shantavira 17:28, 5 September 2006 (UTC)

Me? England. I thought this beastie looked smallish too, given its size against the leaf. Happy to be corrected though. Skittle 17:30, 5 September 2006 (UTC)

Thank you for your reply. The insect is pretty small, about 3-3.5 cm including the antennas. The garden is in northern Italy. Davide125 18:21, 5 September 2006 (UTC)

It is some sort of bug - that's as specific as I can be, I'm afraid. You can tell it's a bug by its long ventrally retracted mouthparts, just visible in the photo. BenC7 10:08, 7 September 2006 (UTC)

Just from having a quick browse, it appears to be from one of the families of heteroptera. Maybe a type of leaf-footed bug. BenC7 10:15, 7 September 2006 (UTC)

Construction of Light Emiting Diodes (LEDs)

I am particularly working on a project whereby I need to construct a 2-Volts-DC LED lighting — 17:38, 5 September 2006 (UTC)17:38, 5 September 2006 (UTC)83.229.66.186

Construct from what starting point? Do you have a handful of LEDs and resistors from Radio Shack? Do you have a some PN junctions? Do you have some appropriately-doped pure semiconductors? An undoped Si crystal? A pail of beach sand? DMacks 19:03, 5 September 2006 (UTC)

Hehe, I have sometimes thought about how long it would take to, say, build a computer, if all you had to start with was the natural resources. One could imagine that mankind, because of a natural disaster or something, lost all of present technology. Mabye there is only some tenths or hundreds of people left. How many generations would it take to build a computer (or go to the moon, or build a submarine, …)? The first generation would have to try to pass on all their knowledge to the next (a great task in itself), but they hardly know everything, so future generations would have to, well, not reinvent the wheel, but a whole lot of other things. Or could it be accomplished while the starting generation is still alive? —Bromskloss 21:33, 5 September 2006 (UTC)

Make sure you download Wikipedia (how is that even possible) before the downfall of civilization. It would give quite a jumpstart. Imagine Michael Faraday or Joseph Henry with a laptop containing all Wkipedia articles, and the jumpstart it would give science and technology.(I chose their era so they could build batteries to power it). Edison 15:11, 6 September 2006 (UTC)

Yeah, but when they found out that (on the day of download) "My teacher says that Isaac Newton is soooo gay!", they might not want to work with him anymore. ;-)

Atlant 00:06, 7 September 2006 (UTC)

Given that you have the led and a 2 volt light source, the big trick is to connect the led so that it is biased to conduct electricity, and to have a resistance in the circuit to limit the current to an appropriate amount. See LED circuits. An LED connected across a battery without a limiting resistor would generally fry when forward biased. Edison 20:24, 5 September 2006 (UTC)

A lot of modern LED flashlights seem to skip the limiting resistor and just count on the battery's internal impedance to limit the current flow. Given the rather small difference between 2V supply and the forward voltage of the diode, the choice of resistor is pretty problematic anyway: the correct value of the resistor would be very sensitive to small variations in the battery voltage and the LED forward voltage. Many modern designs now get around this dilemma by using sophisticated active regulator ICs rather than mere passive resistors. The active regulator also wastes less power than a passive resistor and allows draining the battery further, optimizing its service life.

One reference: http://www.elecdesign.com/Articles/ArticleID/13284/13284.html

(But Google will find you many more)

Atlant 00:11, 7 September 2006 (UTC)

what kind of mirror has best reflection of visible light ?

I want to know how much percent the best mirror for the visible light,reflects ? —The preceding unsigned comment was added by J.hesam (talk • contribs) .

Maybe spectralon. Its reflectance exceeds 99%.---Sluzzelin 19:07, 5 September 2006 (UTC)

The "Technology" section of the Mirrors page has some info. DMacks 19:08, 5 September 2006 (UTC)

Dielectric mirrors can reflect >99.999% of a narrow band of wavelengths. In 1998, MIT claimed they had created a so-called perfect mirror that was a "very efficient reflector over a broad range of angles". I haven't been able to find any exact numbers or more recent details about it, though, so it might not be much more than a research prototype. -- Plutortalkcontribs 19:11, 5 September 2006 (UTC)

I found a few (potential) primary citations for that work...see Talk:Perfect mirror). DMacks 19:27, 5 September 2006 (UTC)

Sluzzelin: the spectralon article claims that it has a very high diffuse reflection, so it's definitely not a perfect mirror. – b_jonas 21:27, 5 September 2006 (UTC)

Dielectric mirrors, as mentioned. — [Mac Davis] (talk) (Desk|Help me improve)

See total internal reflection. Of course you have to be inside the high-refractive index medium. --Trovatore 04:54, 6 September 2006 (UTC)

...and you have to be away from perpendicular. List of indices of refraction suggests that 4 is a very large value for n and 1 is smallest. That interface would give a θ_c of about 14.5 °, meaning there's a ~29-degree cone of non-mirroring. DMacks 05:30, 6 September 2006 (UTC)

Is there such a thing as an active (powered) mirror that amplifies the incoming light, thus exceeding 100% reflection? DirkvdM 09:35, 6 September 2006 (UTC)

I don't know, but there are shaving mirrors with fluorescent lamps in their frame that illuminates your face. – b_jonas 12:02, 6 September 2006 (UTC)

Lasers do this (monochromatically). Linear cavity lasers do this by design. (Ring lasers, ..., not so much.) There are patents for 3-color image intensifier goggles, but I don't see how one could do this in the form factor of a mirror. -- Fuzzyeric 06:57, 7 September 2006 (UTC)

What would happen

if an unstoppable force collided with an immovable object (assuming it were possible)? A Clown in the Dark 18:22, 5 September 2006 (UTC)

Irresistible force paradox ---Sluzzelin 18:51, 5 September 2006 (UTC)

Ah, that was simple. Thanks! A Clown in the Dark 18:52, 5 September 2006 (UTC)

I think this is Lambiam's principle of explosion. :) Rentwa 21:11, 5 September 2006 (UTC)

I love that paradox. --Proficient 04:07, 6 September 2006 (UTC)

Makes me wonder. Is it possible to ask a question that hasn't been asked before? How many people will already have asked that question? (And how many people will already have asked that (and how many ... ok, let's rule out recursion)). DirkvdM 09:37, 6 September 2006 (UTC)

Maybe there should be a continuously updated index of all the questions that have ever been asked on the Ref Desk. Of course, that would require them having meaningful titles, not just things like "Question", or "What would happen". You seem to have a bit of spare time on your hands, Dirk, so why don't you get the indexing project started. Call me if you have any questions.  :--) JackofOz 10:19, 6 September 2006 (UTC)

What, with all the time I spend on the ref desk, what makes you think I've got spare time on my hands? Or was that your point? Well, it's mine too. (reminds me of the question of whether the presence of a lot of police in a neighbourhood means it's very safe or very unsafe) DirkvdM 18:00, 6 September 2006 (UTC)

faqs.org has a quite good index of FAQs in various topics. – b_jonas 11:56, 6 September 2006 (UTC)

The unstoppable force would simply change direction - it would 'bounce off the immovable object.

In a sense this happens every day, when two objects are in compression against each other - one is an unstoppable force, the other is unmovable.

Errr...it would not change direction. For the unstoppable force to change direction, it would have to stop.

It would not have to stop if it changed direction instanateously. If for example, you fired a bullet at a heavy steel plate it would not stop but ricochet.

genetically modified foods

what is the mean of genetically modified foods?

Basically it is transformation with new DNA, often from an unrelated organism. David D. (Talk) 21:11, 5 September 2006 (UTC)

Perhaps typing "genetically modified foods" into the Search box would have been a good place to start learning on your own... DMacks 21:13, 5 September 2006 (UTC)

Do you mean what the average genetically modified food is or what the meaning is or why they are mean? Or am I being mean now? (And don't tell me I'm average, or I'll get really mean.) DirkvdM 09:41, 6 September 2006 (UTC)

What is the process of liqiudizing Oxygen?

I just want to ask a question about liquidizing Oxygen. Thank you. --64.180.82.114 21:40, 5 September 2006 (UTC)

According to Liquid oxygen, the usual process is fractional distillation. I guess you just condense ordinary air first. Melchoir 21:42, 5 September 2006 (UTC)

You would also need to lower the temp quite a bit, wouldn't you ? StuRat 22:51, 5 September 2006 (UTC)

Liquid air talks about how to condense ordinary air, including separation of different components by their boiling point. DMacks 23:01, 5 September 2006 (UTC)

Ah, there's the money link. I've put it into the See also. Melchoir 23:20, 5 September 2006 (UTC)

On a lab scale (do not try this at home!) passing a flow of oxygen gas thorough a liquid nitrogen cooled copper coil gives access to tens of mLs of liquid oxygen terrifyingly quickly. for great fun for those slow fridays, i recommend cotton wool. Xcomradex 02:28, 6 September 2006 (UTC)

How about the Linde process for the liquefaction of air?--Light current 18:05, 6 September 2006 (UTC)

Information on the Linde process is currently scattered among Carl von Linde, Liquid air (already mentioned), and Joule-Thomson effect. I'm not sure where the redirect for Linde process should point. Or maybe it should be unified into its own actual page? DMacks 18:12, 6 September 2006 (UTC)

It must be (or have been) an important process: I remember covering it at school! Redirect should point to liquid air--Light current 18:47, 6 September 2006 (UTC)

Reference voltage for decibel measurement

When calculating frequency repsonse on electronic hifi equipment, what is the reference voltage for the decibel measuremnet used in a frequency vs dB graph? Is it the ' perfect ' output voltage?

I think its 0 dBm ie 775 mV rms (in a 600R system).--Light current 23:58, 5 September 2006 (UTC)

Many experimenters fail to control impedance in calculating/measuring decibels. And did you mean 600 ohms? Did dBm mean "decibel referenced to a milliwatt across 600 ohms? Edison 15:39, 6 September 2006 (UTC)

Yes in 600 ohms (R is the unit for ohms) Try this calc [22] --Light current 17:57, 6 September 2006 (UTC)

The graph shows gain, which is output power divided by input power. The reference is therefore the input. There is no need for an arbitrary reference level. See this random example I found on Google. The y axis is marked 'Gain', as it should be. --Heron 22:00, 6 September 2006 (UTC)

Remember, all decibels are just a ratio between two values. So when an amplifier states (for example), that it has a frequency response of 20Hz to 20KHz ± 0.1 dB, what that means is that if you plotted the frequency response from 20 Hz to 20 KHz, the line that represents the frequency response would stay within a band that is 0.2 dB high. In this case, the ratio you're measuring is the ratio between the best gain of the amplifier (within our specified frequency band) and the worst gain of the amplifier (within our band).

Any time you see dB representing an absolute value, there'll always be some indication of what the value is ratio'd from. For example, the dBm that folks were speaking of above is a ratio from 1 milliwatt. If someone says dBV, then they're expressing a ratio from 1 volt. dbA is a ratio of acoustic power related to a particular absolute value of sound pressure level (the softest sound the average person can hear at 2KHz) and weghted according to an "A" frequency response curve (a particular weighting curve that has something to do with the response of human hearing).

Atlant 01:05, 7 September 2006 (UTC)

canine dental

I have a five month old Standard Poodle, that has adult teeth coming in missing enamel on 1/3 to 1/2 of each tooth. I am researching the probability of heredity/genetic traits to notify the breeder of possible health related concerns. All her teeth will have to be capped to prevent decay. I have read many articles suggesting auto-immune issues; and want more information on related documented cases and results. I can send pictures. Thank you. <Do you want Viagra for only $10?>

I'm only familiar with enamel hypoplasia in dogs as related to canine distemper, but according to the Merck Veterinary Manual, it can also be caused by malnutrition and possibly inherited [23]. --Joelmills 01:46, 6 September 2006 (UTC)

Yes, thank you. Dr. Bellows, dentalvet, has the same opinion.

My journey: (1) is to find out if this is related to the 3- series puppy-shot that contain "parvo, influenza, distemper & hep." when administered with an undetected low-grade fever, (2) or, if there is a heredity-gene trait and is there a genetic test available? (3) to answer a question swarming my brain; what could destroy the mineral presentation of "Hydroxyapatite" during the "Odontoblast period" of the "Dentinogenesis" formation?

I am no scientist or practioner....just want answers to why my puppy has permanent damage to all her adult teeth, like a line was drawn and half of each tooth has no enamel. It is suggested that the "leukocyte alkaline phosphatasa" found in white blood cells, could lead my way to more knowlegde. I will have her tested for amenia and hypothyroidism. Perhaps the vaccines, eliminated the part of her immune-system that protects the "Dentinogenesis" formation.

September 6

Ejaculation

Is there any way of shortening the "refill time" after I've ejaculated semen from my penis? Do any of those pills you see advertised on the internet that claim they do this really work?

The "refilling time" you refer to is called a refractory period Raul654 00:30, 6 September 2006 (UTC)

Also, from that article, The refractory period varies widely between individuals, ranging from minutes to hours. An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the refractory period and the amount by which oxytocin is increased may affect the length of each refractory period. Another chemical which is considered to be responsible for this effect is prolactin, which represses dopamine, which is responsible for sexual arousal. So I suppose any enzyme that breaks down either prolactin or oxytocin could theoretically decrease the time of a sexual refractory period. Raul654 00:32, 6 September 2006 (UTC)

Perhaps training yourself to need less time will work. --Proficient 04:12, 6 September 2006 (UTC)

What sort of training did you have in mind?--Light current 18:00, 6 September 2006 (UTC)

I consider myself an expert in the field and would definetely recommend "milking" which would induce your body to keep up with the demand. - Tutmosis 01:26, 7 September 2006 (UTC)

Can you eleaborate?--Light current 14:31, 7 September 2006 (UTC)

Its very simple, milking is forced (A.K.A planned & executed) masturbation a number of times a day to force your body to increase sperm production as well as the rate. Years of training will give you results so great that you will even forget what being "dry" means. - Tutmosis 00:36, 8 September 2006 (UTC)

OK thats assuming you can do it more than once a day. You must be a youngster! Enjoy it whilst you can! 8-)--Light current 00:38, 8 September 2006 (UTC)

I have to admit I dont have the swing I used to have but I'm sure with hard work and devotion we can all "spray the goodness" again. - Tutmosis 00:48, 8 September 2006 (UTC)

o_o --Froth 20:27, 8 September 2006 (UTC)

TMI Raul654 20:35, 8 September 2006 (UTC)

AS long as youre not doing it whilst editing, I can deal with that! 8-)--Light current 00:50, 8 September 2006 (UTC)

Mouthwash, alcohol, toxicity, &c.

I hold in my hand a travel bottle of Scope® mouthwash, a generous, easily-confiscatable gift from the good people at Continental Airlines. In the air, I wondered out loud whether one could obtain more alcohol from the bottle of Scope than from the little bottles of wine they were giving out. I also secretly suspected the Scope would be less sweet. I was thinking of the old comedy trope of the high school kid getting wasted on Listerine or the Vietnam veteran hooked on cough syrup. But, as I discovered a minute later, the label advises any unlucky ingester to contact a poison control center immediately. This Scope contains 15% alcohol by volume, as well as water, glycerin, "flavor", polysorbate 80, sodium saccharin, sodium benzoate, cetylpyridinium chloride, benzoic acid, blue 1, and yellow 5. Presumably cetylpyridinium chloride is the toxin, but in what concentration does it pose a threat to the human body? I remember, as young children, my brother and I unwittingly drank brimming Dixie cups of the stuff, not realizing the idea was to spit it out. Nor can I recall suffering any ill effects. I ask someone with a knowledge of chemistry: Is the Listerine lush an inaccurate or outdated trope (perhaps due to an advance in mouthwash technology), or alternatively, has the toxicity of mouthwash been exaggerated, perhaps to prevent lawsuits and substance abuse? Bhumiya (said/done) 04:59, 6 September 2006 (UTC)

Here's what Straight Dope says: [24] -- Scientizzle 05:19, 6 September 2006 (UTC)

Interesting. Thanks for the quick response. Bhumiya (said/done) 05:30, 6 September 2006 (UTC)

And wow, who would ever think of replacing mouth wash with pure vodka with a little food coloring???

Genetic Gender

Why do some couples have say three girls, whilst other have three boys? Is this just the luck of the draw, or is there something else going on, like a genetic leaning toward having children of a certain sex?

See Sex ratio, Sex-determination system and XY sex-determination system for the genetics behind it. It's essentially the luck of the draw, as I understand it. --Robert Merkel 09:14, 6 September 2006 (UTC)

Statistics is one of the least understood things (alas, because a good understanding of it is essential to understanding the world around you). Having 10 children of the same gender sounds so unlikely that the couple that had them would probably think there was something special going on. But the chances are 1 in 512, which makes it likely that once in a while it will happen (if there are enough cuples that have 10 kids, that is). But then people will think that the fact that it happened to them specifically is significant. It isn't. No-one would think anything of having 3 boys and 7 girls in a specific order, but he chances are exactly the same. DirkvdM 09:52, 6 September 2006 (UTC)

"The chances are exactly the same" — that's true, but when most people say that MMMMMM looks more un-random than MFFMFM, they usually mean something more akin to "the odds of getting a non-homegenous pattern are much higher than getting a homogenous one", which is true. Unfortunately I doubt most people know that's what they're actually referring to when they say the first sequence looks more significant than the latter. It's the same thing as when statisticians deride people for choosing 010010 as the "more random" sequence than 000000; if each element is independently determined, then any single outcome is as likely as another, but if one is instead taking a more intuitive, "homogenous/nonhomogenous" approach then indeed, you'd expect more truly randomly generated sequences to "look like" the first one than the second. --Fastfission 18:14, 6 September 2006 (UTC)

I remember hearing that certain conditions could lead to men having more girls than boys. I think it was high levels of testosterone, which can also lead to early baldness. I don't have a source for this though, but I'm sure Karl Kruszelnicki mentioned the link once. If anyone has better info it'd be appreciated. I should probably check the articles mentioned too. —Pengo ^{talk · contribs} 11:47, 6 September 2006 (UTC)

The sex ratio article links to a couple articles about research that indicate that men infected with Hepatitis B have more male children. There was also some recent press about a study that showed that attractive people were more likely to have female children and some articles mentioned previous studies by Satoshi Kanazawa that showed that scientists, mathematicians engineers, big or tall parents and violent fathers are all more likely to have sons than daughters. It seems pretty certain to me that all couples do not have the exact same 50-50 chance of boy and girl children. -- Plutortalkcontribs 13:02, 6 September 2006 (UTC)

It's not a 50-50 chance, even on the average. More boys are born than girls. --Trovatore 21:10, 6 September 2006 (UTC)

Note however, that the the ratio of sexes born need not be the same as the ratio of sexes conceived. The sex of a foetus will be determined at conception, however, during the 9 months in utero, there could well be differences in survival rates between sexes. There could also be genetic predispositions to bearing children of one sex over the other, theoretically at least. For example, consider a mother who has an allele on one of the X-chromosomes that, when hemizygous would cause early embryonic lethality by haploinsufficiency (lets ignore the problems that Lyonisation would cause her or her female children, for the moment). All else being equal, every child born to her would have a 1/3 probability of being male, rather than a 1/2. However, the probability of her conceiving a child of either sex remains 1/2, respectively. I am not familiar with an exact gene that this model would fit this example, but i'll wager it happens. Thus having multiple children of the same sex is most often simply due to chance, but i would argue that a specific genetic predispositions cannot be ruled out. Rockpocket 01:12, 7 September 2006 (UTC)

I think you're wrong about the probability of conception for either sex being 1/2. If I recall correctly, male fetuses are more likely to die before birth, so the disparity at time of conception must be even larger than the disparity at time of birth. Of course, that could be rolled into your "other things being equal", but my point is that other things are not equal. --Trovatore 03:50, 7 September 2006 (UTC)

Possibly true. However, the problem with the data you mention, is that it is based on later-pregnancy miscarriages. As much as 50% of all conceptions fail: its thought that around 1/4 of fertilized eggs fail to implant in the uterine wall and 1/3 are spontaneously aborted within the first six weeks after conception, both without the mother ever knowing she is pregnant. Since we have no idea of the sex ratio of these failures, the impact of the (relatively speaking) small number of later-stage male-biased miscarriages could be negligible. If these early failures balanced up the sex bias, your logic would fail. My assumption of equality was to demonstrate my theoretical point on the difference between conception/birth ratios in a simplified model. The fact is, we simply don't know if "other things are equal", as we don't have a full data set. Rockpocket 05:40, 7 September 2006 (UTC)

I think that's a stretch, frankly. The ratio of Y-carrying androsperm to X-carrying gynosperm is known, and the ratios of later fetuses is known, and both (unless I'm misinformed) support the idea that there are more male conceptions. I think you're overapplying the notoriously shaky principle of indifference. --Trovatore 07:33, 7 September 2006 (UTC)

I completely agree. Per Occam's razor, that certainly is the post parsimonious explanation. However, the possibility remains, however remote... Rockpocket 18:20, 7 September 2006 (UTC)

Sleep

Why do I get a headache if I'm fortunate enough to get too much sleep? And is this a common reaction to sleeping too much? Dismas|^(talk) 10:32, 6 September 2006 (UTC)

It's a known phenomenon. This article discusses a possible mechanism. --Lambiam^Talk 10:49, 6 September 2006 (UTC)

How much is too much, because I can't say I've ever had a headache from this. --liquidGhoul 11:00, 6 September 2006 (UTC)

I find it usually happens when I go to sleep again, i.e. when I half-wake up, decide that I don't want to get up at this time today, and wake up again a few hours later with a headache.  freshofftheufoΓΛĿЌ  14:03, 7 September 2006 (UTC)

Actually that article doesn't say much. It can be many things, including but not limited to:

1. Musculoskeletal discomfort due to prolonged immobility, imperfect bedding, or uncomfortable position;
2. Overheating;
3. Mild dehydration;
4. Low blood sugar;
5. Caffeine withdrawal;
6. Low blood pressure;
7. Poor sinus drainage (exacerbated by being prone);
8. Sleep apnea. Oxygen deprivation causes headaches, and the longer you're experiencing it, the worse a headache you'll get.

--Anchoress 11:09, 6 September 2006 (UTC)

Sn1&Sn2 Reactions

please tell me about following things in sn1 & sn2 reactions

1.Nature of substract
2.Nature of attacking nueclophile
3.Nature of leaving ion
4.Nature of solvent

It would probably be best if you look at SN1 reaction and SN2 reaction then come back with any specific questions you still have.--Ed (Edgar181) 13:59, 6 September 2006 (UTC)

A car for $1

What would you do if you see an ad like this:

• Offer for sale of EXACTLY ONE $30,000 car for $1.
• First come first served.
• However, you're required to throw a die:
  • If the 1st one in line gets a "1"; he/she takes the car home.
  • If the 2nd one in line gets a "1" or "2"; he/she takes the car home.
  • If the 3rd one in line gets a "1", "2" or "3"; he/she takes the car home. ...
  • Whatever 6th one in line gets; he/she takes the car home if all previous five did not make it.

If you want that car, what is your strategy to maximize your likelihood of winning? -- Toytoy 13:59, 6 September 2006 (UTC)

Just work out the probabilities. The first guy has a 1/6 chance of winning a roll, and a guaranteed chance to roll. The next has a 2/6 chance of winning if he rolls, but only a 5/6 chance of getting to roll. The calculations proceed thusly. — Lomn | Talk 14:17, 6 September 2006 (UTC)

I should note: a more interesting question is "what is a fair price for the chance to win the car?" Obviously the seller can't recoup his $30000 with $1 tickets, but if the tickets are only bought when the die is rolled (rather than in advance), what should he charge to average $30000 worth of tickets sold? — Lomn | Talk 14:21, 6 September 2006 (UTC)

Require 100 sided dice, then be last in line.

Hire some gorillas to prevent anyone else from queueing. So long as the hired help costs less than $29,994, you'll walk away smiling. --Dweller 14:28, 6 September 2006 (UTC)

Go 2nd or 3rd, it doesn't matter which.

Person I	Chance of rolling I	Chance of winning roll I	Odds of getting car I
1	1.00	0.17	0.17
2	0.83	0.33	0.28
3	0.56	0.50	0.28
4	0.28	0.67	0.19
5	0.09	0.83	0.08
6	0.02	1.00	0.02

- Nunh-huh 20:26, 6 September 2006 (UTC)

It might be an intersting game theory problem if you had a group of 6 people who each had to volunteer to go first, second, third etc. You'd have to set up the mechanism for volunteering in some specific way, but it might be interesting. --best, kevin [kzollman][talk] 21:43, 6 September 2006 (UTC)

If I saw this ad, and was able to determine it was not a marketing promotion, I would ignore it as a probable scam of some type, simply because common sense says that reasonable people don't just give away expensive cars. --Ginkgo100 ^{talk · e@} 21:50, 6 September 2006 (UTC)

Yea, like you may only be able to get the car for $1 if you agree to pay $40,000 for the car keys. :-) StuRat 23:35, 6 September 2006 (UTC)

If the car is legally yours, I'm pretty sure you could get new keys made (or the locks replaced) for less than $40,000. (In fact, you could probably get new keys to a car for less than $40,000 even if it wasn't legally yours, but that could cause other kinds of problems further down the line...) —Ilmari Karonen (talk) 01:26, 7 September 2006 (UTC)

I'm saying that the car wouldn't be legally yours (they wouldn't sign over the title) until you bought the $40,000 key, hence the trick. StuRat 06:36, 7 September 2006 (UTC)

I actually saw an ad once for a hideously expensive bicycle, that cost like a car, and you got a car with it. :-) —Bromskloss 13:54, 7 September 2006 (UTC)

BTW, this question should have been posted to the Math Ref Desk. StuRat 23:37, 6 September 2006 (UTC)

I'd buy all six tickets for $1 each, that's still just $6 for a $30000 car. – b_jonas 08:53, 7 September 2006 (UTC)

That answer sounds strangely familiar. --Dweller 09:40, 7 September 2006 (UTC)

yDNA Mutation Rates

What are the relative Mutation Rates of yDNA STR's used in Genetic Genealogy?......... Cymri

there are no good reliable published figures for those differential rates. The closest you'll get is a statement that a given STR is a "slow" (or "fast") mutater. - Nunh-huh 20:02, 6 September 2006 (UTC)

Ok Can anyone list the "fast" and "slow" Loci? or perhaps provide a limk to such information. cymri

Recognize this optimization problem?

I need to find a search algorithm for the following optimization problem. We are given $N$ (smallish) finite sets $A_{k}$, and we are to choose one element from each, to yield a multiset $B$ of size $N$. We are also given a finite mapping $\omega$ from multisets to real-valued weights, and we are to maximize the sum of the weights associated with the submultisets of $B$, $\sum _{C\subseteq B}\omega _{C}$.

If we constrain the domain of $\omega$ to multisets of size $1$, we can choose from each $A_{k}$ independently, and the problem is trivial.

If necessary, I can afford to constrain the domain of $\omega$ to multisets of size $2$, but I'm beginning to suspect that this is already NP-complete.

If it is NP-complete then I would appreciate any advice on approximations or reductions to other problems for which good solvers are available. Can I do better than the obvious reductions to ILP or weighted MAX-SAT?

Thanks and best wishes 128.220.220.95 19:20, 6 September 2006 (UTC)

I suggest you move this to the Mathematics reference desk. --Lambiam^Talk 23:02, 6 September 2006 (UTC)

Good point. I will start there next time. 128.220.220.95 17:00, 8 September 2006 (UTC)

If we allow $\omega _{C}\not =0\;\forall \left|C\right|\leq 3$, this problem would solve boolean satisfiability (in particular 3SAT), as you hinted with MAX-SAT. Consider $A_{k}=\{(k,0),(k,1)\}$; then, for each value $(k,i)$ in a disjunction (that is, $(k,0)$ if $\lnot x_{k}$ appears, and $(k,1)$ if $x_{k}$ appears), increment $\omega _{\{(k,i)\}}$. Then undo the double counting (where $(\lnot )x_{k}$ and $(\lnot )x_{k'}$ succeed in a term containing both anyway) by decrementing $\omega _{\{(k,i),(k',i')\}}$ for each pair of literals that appear in the same disjunction. Then repair three successes minus three handshakes by incrementing $\omega _{\{(k,i),(k',i'),(k'',i'')\}}$. Then maximize, and see if the result has value equal to the number of disjunctions (this can be done in polynomial time because there are no more than ${N \choose 1}+{N \choose 2}+{N \choose 3}\in O(N^{3})$ non-zero values of $\omega _{C}$). This reduction typically involves negative weights, which you might not have had in mind, but I imagine that it could be recast without them. Obviously the corresponding argument with $\left|C\right|\leq 2$ fails because it's 2SAT then, so I'm afraid I don't have any truly useful answer at the moment. Hope this helps. --Tardis 23:20, 6 September 2006 (UTC)

Very cool, and I believe I've just learned something from the 2-satisfiability article that allows me to finish your argument: 2-SAT can be done in polynomial time, but MAX-2-SAT is NP-complete. It looks like I'm back to the drawing board, so thanks for helping me figure that out sooner rather than later. 128.220.220.95 17:00, 8 September 2006 (UTC)

Dogs and people

I know that any answer to this question must remain as speculation: What do dogs think humans are? They must not think of us as fellow dogs, because we probably smell different, and they do not try to mate with us. Are they usually submissive because we appear to be much larger members of some other species? Does Wikipedia have any articles on this subject? Pete

There is a lot of debate over exactly how dog/human relations are or ought to be (i.e. does the human master represent the alpha pack member?), but I think one can say somewhat safely that most animals are not able to get into the sorts of relationships that dogs have with humans (even cats seem to have difficulty tolerating humans a lot of the time, much less non-pet animals), and it is precisely this character trait which has made dogs "man's best friend" as they say. For whatever reason they seem to be able to adapt to co-habilitation with humans very well, and many dogs seem to exhibit symptoms of real affection for their human owners (one can always wonder if it is a trick, but I'm pretty sure my dog likes me—she goes way above and beyond what would be necessary to get food and attention). Of course dog behavior towards humans can vary a lot with breed—some breeds are notoriously independent and stubborn, some are very easy to train, some are known to be very friendly towards people, and some are known for their ability to be quite violent to humans. Unfortunately we don't seem to have a lot on this (our Behavior subsection of the "Dog" article is really, really short). We have a short article on Companion dogs but it doesn't have much on dog psychology. --Fastfission 20:31, 6 September 2006 (UTC)

I'm not sure its proper to attribute the sort of cognitive abilities to dogs that allow them to classify us. Perhaps dogs don't classify animals in their environments in the same way humans do. It might not "occur" to a dog to ever think about what we are. I don't know much about research into animal cognition, but I'm not sure if there is any reason to think they classify their environment into species. --best, kevin [kzollman][talk] 21:40, 6 September 2006 (UTC)

Just a couple of things to add. Many dogs actually do try to "mate" with us, or at least our legs. As for being submissive to larger creatures, it may be counterintuitive but the truth is that the larger the dog, the more gentle and submissive it is. It tends to be those tiny rat-dogs, the Chihuahuas, the Toy Poodles etc. that tend to be the nastiest and the most anti-social towards many humans. Have you ever been growled or been given dirty looks by a giant St. Bernard or Golden Retriever? Loomis 21:47, 6 September 2006 (UTC)

Based on my (limited) observations of dogs, individual dogs behave in a somewhat consistently different way with respect to members of different species: they don't greet cats like they greet dogs, and a dog that chases one unknown cat tends to chase them all. Yet the same dog will not chase humans, only bark at them. To the extent that it is reasonable to apply human labelling to what dogs "think", my best guess is that dogs think that dogs are dogs, cats are cats, and humans are humans. --Lambiam^Talk 23:12, 6 September 2006 (UTC)

We do have two relevant articles -- Animal cognition and Dog intelligence. --Halcatalyst 23:21, 6 September 2006 (UTC)

I go with dogs viewing their owner as the pack leader/alpha dog, whereas cats view their owner as their mother (even male owners). StuRat 23:20, 6 September 2006 (UTC)

This article from the NYT has something about the problems created by framing the interaction with your dog in the alpha dog theory. Dogs are not wolves, but also for a pack of wolves the social structure is not like that of a troop of chimps. --Lambiam^Talk 04:09, 7 September 2006 (UTC)

Supporting that thought... the best way to completely immobilize a cat is to pick it up by the scruff of its neck, like the mother cat does. --Halcatalyst 23:23, 6 September 2006 (UTC)

The immobilization reflex is mechanical and has nothing to do with how the cat views us. --Lambiam^Talk 04:09, 7 September 2006 (UTC)

Behaviourists from John B. Watson to B.F. Skinner saw no need to postulate what animals or people thought. Instead they saw our actions as the result of behavioural conditioning. The question of what a dog thinks a person is would be as meaningless as the question of what a person thinks a dog is (toy? child substitute?). They might note behaviours such as a cat kneading the owner stomach as learned from the utility of that conditioned response in obtaining milk from the mother. Cognitive psychologists theorize about internal mental states and how they control behaviour.

Many dog owners would say that dogs seem to think they and people are not that different, whether it be two kinds of dog or two kinds of people. Edison 23:40, 6 September 2006 (UTC)

Hmm. Sounds like a classical case of psychological projection to me. --Lambiam^Talk 04:13, 7 September 2006 (UTC)

I thought if the dogs were bigger, the more agressive and less social they were. ._. --Proficient 04:18, 7 September 2006 (UTC)

St. Bernards are quite large, but they're highly social as well as gentle. Behavioural traits aren't necessarily tied to the size at all; I've seen small dogs that are insanely aggressive. -- Consumed Crustacean (talk) 04:25, 7 September 2006 (UTC)

I believe the counterintuitive result that small dogs are more aggressive is due to artificial selection. While an aggressive small dog is considered by some to be acceptable, or even cute, an aggressive large dog is seen as dangerous. Thus, aggressive large dogs were less wanted and less likely to be bred than aggressive small dogs. After a few thousand generations, this leads to a lack of aggressive, large dog breeds. StuRat 04:29, 7 September 2006 (UTC)

That is entirely possible. Behaviour doesn't occur in a vacuum, however, and another factor is fear. Most animals will display aggressive behaviour when they feel threatened or harrassed - the fight part of fight or flight. The size of a dog in relation to the threatening cue is a factor in where they feel threatened or not, hence small dogs may be more likely to be aggressive than large ones, simply because they are more afraid. Genetics play a role in this too, of course. Note that we have bred larger dogs to be working dogs. Having them afraid of, or aggressive with, humans is not an ideal characteristic for their function. So that has been selected against. On the other hand, small show dogs are bred for how they look, so their fear of humans (as StuRat suggests) is inconsequential for their function. Rockpocket 06:00, 7 September 2006 (UTC)

William Gray (Meteorologist)

I have searched all over the internet for some background information on William Gray the hurricane forecastor and am unable to find out his birth date, where he was born and general information on his childhood. I did find ample information on the work he has done in hurricane forecasting but would be very gratefull if someone could help me on his background.

regards,

mactennis.

A recent article[25] says he's 76. That narrows his birth down, so you can try more searches to pinpoint it. Melchoir 21:06, 6 September 2006 (UTC)

Trying to get glasses

Three years ago I failed my school's eye exam and since then I have been to the eye doctor three times. Each time, the doctor told me that I was really close to needing glasses but my perscription is so small it would not even be worth it. Is there anything I can do to tip the scales in favor of requiring glasses within the year? Advice would be appreciated.

Usually I respond to people who are honest. Just say - "it may be a small correction, but it really means a lot to me. Could you please prescribe me glasses so I can use them when I feel I need to?" If they will not sell you glasses, ask for your refractive error. If all else fails, see a different doctor! InvictaHOG 01:28, 7 September 2006 (UTC)

Watch television up close, read in the dark, and neglect your carrot consumption. Staring at wikipedia pages all day will probably help too. AEuSoes1 02:20, 7 September 2006 (UTC)

I think I once read that reading in the dark doesn't hurt your eyesight, but that might have been a myth. --Proficient 04:20, 7 September 2006 (UTC)

Yeah, I don't see how it would. Carrots also don't help with eyesight. I was being facetiously misleading. AEuSoes1 05:31, 7 September 2006 (UTC)

How often do you masturbate, any room for improvement? Some people continue to believe that "self abuse" leads to deterioration of eyesight. That is almost universally dismissed by doctors as untrue, of course, but what have you got to lose ;)? In all seriousness, it is inadvisable to try any technique to make your eyesight worse. Anything the might work would also run the risk of damaging your eyes. Your optometrist is most likely delaying the inevitable out of a misplaced concern that you might not wish to have specs. as InvictaHOG suggested, I would recommend explaining honestly and firmly that you would like to have your vision corrected and would appreciate if they could do that for you. If they can't, take your future business elsewhere. Rockpocket 06:44, 7 September 2006 (UTC)

You obviously think you need glasses, but why? If you are having difficulty in reading small print, pick up some cheap reading glasses at a drug store/chemist.--Shantavira 07:16, 7 September 2006 (UTC)

• The doctor said the prescription was too small to require correction. Have you ever asked him what the values where. If it was anything up to 0.5 of correction, he is probably correct about you not needing correction. By the way, the fact you go to the eye doctor once a year (or at least three times in three years) is something you should continue. Having your eyes checked should be something as regular as having your teeth checked. - Mgm|^(talk) 07:28, 7 September 2006 (UTC)

I was like this, aged about 10. I thought that wearing glasses would improve my appearance(!) (Sigh) I even pretended in sight examinations that I couldn't read very small letters on the sight chart that I actually could read. I was therefore prescribed glasses of the wrong prescription, before I needed them. I've been wearing glasses ever since and now can't cope without them. The deterioration of my sight is probably mostly down to nature, but in an ignorant lay manner, my gut instinct is to attribute some of the blame to this stupid behaviour. So, my advice (as an ignorant lay person)?

• 1. Don't contemplate pretending your sight is worse than it is
  2. Avoid wearing prescription lenses for as long as you can, within the sensible advice of your optometrist
  3. Don't pick up "cheap reading glasses" that haven't been prescribed for you if you're young enough that "three years ago" you were still at school
  4. Glasses don't make you look clever or glamorous or alluring or mysterious. If you're tempted, think Clark Kent v Superman.
  5. Don't do stupid things that you'll regret later in life.heck, that's what being young is all about, isn't it? Anyway, I ain't young and I do really stupid things all the time--Dweller 10:00, 7 September 2006 (UTC)

Or just buy glasses that have no refraction index?  freshofftheufoΓΛĿЌ  13:52, 7 September 2006 (UTC)

Im puzzled that the school eye exam says you need glasses when a professional optometrist says you dont. I know whom I would believe (the pro)--Light current 14:48, 7 September 2006 (UTC)

September 7

Value of chemical elements

I noticed that the value of germanium in 1997 and 2000 was provided in that article. That sparked the question: what is the best source for determining the current value of such commodities? Is there a reliable web source for finding this information. Much thanks in advance. I'd like to find a consistent source for updating this aspect of the chemical articles. LeyteWolfer 05:57, 7 September 2006 (UTC)

'Spot' markets/commodity markets deal with commonly traded elements. There is data available on rare elements, I saw it recently (osmium data I think, and from a US govt source (less certain abt this)), but I can't remember where. That doesn't help at all, does it? Rentwa 06:53, 7 September 2006 (UTC)

No, I'm afraid not, but thanks for trying. LeyteWolfer 22:22, 7 September 2006 (UTC)

The USGS Mineral Commodities Summaries, here [26] generally include average prices for the years of the reports. Geologyguy 20:05, 8 September 2006 (UTC)

Weight versus elevation.

As you go farther from the center of the Earth, your weight decreases due to a weaker acceleration. How much does your weight alter from the Earth from an increase or decrease in elevation? Say I move from a place of lower elevation to a place of an increase in 500 feet of elevation. About how many pounds theoretically did I lose in weight? -User:NealIRC 7 September 2006 2:05 (UT)

Try staring at Newton's inverse-square force law, and think about the radius of the Earth. Melchoir 02:00, 7 September 2006 (UTC)

It's more complex than one would think, since you can't view the mass of the Earth as a point mass at the center until you are tens of thousands of miles into space. Instead, the mass of each atom, whether solid, liquid (water), or gas (air), must be considered, along with your distance from each atom. I've heard that the force of gravity actually increases slightly when you gain a little bit of altitude, due to the added mass of air below you pulling you down and the reduced mass of air above you pulling you up. StuRat 02:28, 7 September 2006 (UTC)

If we can approximate the physical earth as a nested collection of spherically symmetrical homogeneous shells, then the point mass simplification is fully equivalent for Newtonian physics as long as you stay on the outside. --Lambiam^Talk 02:53, 7 September 2006 (UTC)

Melchior and Lambian are right. It's easy to calculate. Clarityfiend 04:05, 7 September 2006 (UTC)

No, because the atmosphere does count. While it's mass is far less, it is far closer, if you are, say 1 km off the ground, so still has a rather significant effect on the net gravitational effect. Only after you are completely outside the atmosphere would such as approximation become accurate. The density of the Earth is also far from constant, which makes the point-mass model less accurate. See shell theorem for more detail. StuRat 04:20, 7 September 2006 (UTC)

Actually, as long as the density profile is spherically symmetric, the point-mass model is still good. As for the atmosphere... anyone want to crunch numbers on the two competing effects? Melchoir 04:25, 7 September 2006 (UTC)

The atmosphere has no significant effect, since the gravitational force falls off as r squared. There just isn't enough mass close enough to do much. Also, the non-symmetric density of the Earth doesn't really affect things either. The fact is there is a point where, if all the mass of the Earth were concentrated there, you would feel the same gravitational pull. For purposes of the original question, that's good enough. The non-homogeneity might move it a few miles one way or another (the oblate spheroid shape of the Earth too), but who cares? Compared to the distance between the point and the surface, it's negligible. Unless you're looking for ultra-accuracy, Newton's equation will give you a pretty good answer.

Here's a few rough numbers for the effect of the atmosphere (using ballpark figures, but they will give a very loose upper limit). At 120 km up, according to the wikipedia article, an astronaut notices the atmosphere upon reentry, so let's use that. The density of air at sea level is 1.2 kg/m cubed (sorry, don't know how to do superscripts). So a half sphere surrounding our intrepid questioner would mass about 10 to the 15th kg if the density didn't drop off as you go up; for simplicity, I'm going to use that figure. I don't want to go through and have to integrate that, so let's use an average distance of say 1 km. Crunch the numbers and you get about 0.07 Newtons. That's making the terrible assumption that the gravitational force is all in one direction, which it isn't. Even with all the simplifications grossly inflating the force, that's really, really miniscule.

Finally, you'd get a 1% decrease in weight when you are about 30 km further up (roughly - I only have the Windows calculator to work with). Clarityfiend 05:02, 7 September 2006 (UTC)

Again assuming spherical symmetry, the atmosphere does not contribute to the gravitational acceleration experienced by a body on the surface. In general, for a body at distance R from the centre, only the part within a sphere of radius R around the centre contributes to the net gravitational effect. --Lambiam^Talk 09:48, 7 September 2006 (UTC)

On the other hand, whether you are close to the equator or near the poles makes a more important difference in your weight because of the centrifugal force. A quick calculation yields that if you are at latitude φ, the g acceleration you actually feel is reduced by approximately 8.544*10^-4 m s^-2 * cos² φ. This means that if you travel from the poles to the equator, your weight will change by, say, 7 grams. If you travel only within the country it can barely be more than one or two grams. That's however still comparable to the difference you get from the altitude difference above. – b_jonas 08:43, 7 September 2006 (UTC)

The gravitational force is inversely related to the distance squared. So if the distance doubles, the gravitational force is reduced to 1/4. More in general, you should divide the two distances. Assuming Earth can be treated as a point mass at the centre of the actual Earth (so at a distance of about 6000 km), then if you go up 1 km, the distance increases by 6001/6000 = 1,00016666, so the gravitational force decreases to (6000/6001)² = 0,999666 of what it was. Earth's gravity says "an increase in altitude from sea level to the top of Mount Everest (8,850 metres) causes a weight decrease of about 0.28%". Let's do the math again, this time with the more accurate radius of 6372,8 km. (6372,8/(6372,8+8,85))² = 0,997228346. That's a decrease of about 0,0028. Or 28%. So either we're both right or we're both wrong or this is some weird coincidence. :) So if you weigh 100 kg (which I hope not), your weight will decrease by 280 grams when standing on top of mount Everest. That's about the weight of a meal.

500 feet is about 150 m, so that would then be something like a few grammes of weight 'loss'. You do the math. DirkvdM 09:14, 7 September 2006 (UTC)

That's not a meal for a 100 kg person, more like an appetizer. :-) StuRat 09:18, 7 September 2006 (UTC)

Carbon dioxide

With the growing scare in some social circles of the changing temperature on earth, carbon dioxide is constantly brought up as a greenhouse gas that needs to be cut down on. My question is would it be possible to somehow suck (extract) carbon dioxide from the atmosphere and put it in a solid state? - Tutmosis 01:23, 7 September 2006 (UTC)

Try Carbon dioxide sink#Artificial sequestration and Carbon capture and storage. Melchoir 01:27, 7 September 2006 (UTC)

There's way too much in the air for us to ever remove a significant portion with machinery. However, natural removal of carbon dioxide could be increased by increasing the number of land and/or sea plants. For example, algae growth could be encouraged by adding iron to iron-poor sea water. StuRat 02:22, 7 September 2006 (UTC)

I think that's been tried (dumping iron in the sea that is). I think I read about it in Discover magazine; can't remember exactly, but I think it didn't work out too well. (P.S. I think therefore I'm really not certain.) Clarityfiend 04:11, 7 September 2006 (UTC)

You are uncertain, therefore you are. DirkvdM 10:39, 7 September 2006 (UTC)

Yes it has been tried, with mixed interpretations regarding the outcome. More information and links to some of the studies can be found in the articles on Iron fertilization and Iron fertilizing (it has been suggested to merge the two articles). ---Sluzzelin 09:38, 7 September 2006 (UTC)

• There's an easy natural way of removing carbondioxide from the air which has the nice side effect of producing oxygen. It's called trees and if less of those were cut down and more of them were planted, things might be looking up... =- Mgm|^(talk) 07:23, 7 September 2006 (UTC)

See Carbon dioxide sink#Enhancing natural sequestration for that. Not just trees, but plants in general. But their presence alone doesn't do the trick. They need to grow to absorb carbon. So we need fast growing vegetation. Trees are a bad choice for that. Weeds would be better. Of course a useful weed (feel it coming?) would be best. Hemp is a good one. It grows extremely fast and has many uses. Burning it would undo the effect, so that's a bummer for the potheads. But it is also a good source for fibers. Actually, it used to be grown extensively throughout the world for that purpose (for the sailing industry for example), but got discredited because of its 'medicinal properties' (actually, DuPont pushed that to get rid of the competition for their plastic, but that's a differnt story). It also consumes a lot of Nitrogen, which is present in pig poo, of which we have an excess here in the Netherlands, so we would be an excellent choice for doing this (yeah, right, great excuse I hear you think, but its a different variety of the plant I'm talking about here). Another use is for oil, which can also be used as a fuel. That way it gets burned and the CO2 is released back into the atmosphere, anulling the effect, but if it is seen as an alternative to fossil fuels, no CO2 is added the atmospehere - the net result is zero. It's an oil so it should fit into the existing infrasturcture quite well. And the oil company that seems to be most into alternative fuels, Shell oil, is also Dutch, so I wonder if they're looking ito this. DirkvdM 10:39, 7 September 2006 (UTC)

Carbon was/is stored in a solid state in coal, and in a liquid state in oil. The problem is we're releasing that stored carbon. If we could just stop and wait a few million years, maybe more will be laid down... I wonder if, like coal, any solid form we found would be a good fuel, and thus potentially released by later generations? Skittle 10:57, 7 September 2006 (UTC)

pray mantis

how do you identify the gender of a pray mantis insect

It's called a praying mantis. StuRat 01:33, 7 September 2006 (UTC)

Preying mantis might be better considering the following discussion. DirkvdM 10:51, 7 September 2006 (UTC)

Well, they are carnivores (insectivores, to be specific), so they do prey on other insects, but the name is due to their stance, which resembles the common praying stance for people. It's name is an interesting example of anthropomorphitization.StuRat 17:13, 7 September 2006 (UTC)

I believe if you know the species (which is very hard to do), then size plays a major role. I think females are much larger. --liquidGhoul 01:41, 7 September 2006 (UTC)

Size is the best way — [Mac Davis] (talk) (Desk|Help me improve)

Is it true that the female mantis sometimes eats the male after the dirty deed? Or is that a myth? That would be one rather final way of determining the male. Clarityfiend 04:08, 7 September 2006 (UTC)

The article's talk page has a bit of discussion on that. Given the commonness (is that a word?) of the story, the article really ought to address it one way or the other. Melchoir 04:18, 7 September 2006 (UTC)

As always, a great place to go for this kind of stuff is The Straight Dope. Do they have an answer for this one? Yes, they do. EWS23 (Leave me a message!) 05:08, 7 September 2006 (UTC)

Yuck! Thank god I'm not a praying mantis. Clarityfiend 05:53, 7 September 2006 (UTC)

Clarityfiend, you must have missed the article on precisely this topic in Tuesday's Science Times (a regular weekly feature of the New York Times). ---CH 07:52, 7 September 2006 (UTC)

I'm a typing man-tis, ready to figuratively bite off the heads of those who want to impregnate Wikipedia with their POV and lousy prose. Clarityfiend 16:36, 7 September 2006 (UTC)

Possibly I'm being pedantic, but size is only a partial answer, because it's only helpful when used as a comparative. If you had just one specimen of a particular type of praying mantis, (or, for that matter, several hundred all the same size) you wouldn't be able to tell if it was (they were all) male or female. Any other ideas? --Dweller 09:44, 7 September 2006 (UTC)

That's why I said you need to know the species, and obviously their sizes. The females are usually considerably large enough to differentiate. If you get a small praying mantis, it may just be a small species, not neccessarily a male. --liquidGhoul 09:49, 7 September 2006 (UTC)

Vivisection! — [Mac Davis] (talk) (Desk|Help me improve)

Water Ananlysis

Hi, I want to test drinking water with ref. to Hardness, Chloride content & free chlorine content pls. provide me the procedure for same however it should be volumetric analysis...

Thanks & Regards,

Anant BendigeriPatil. +919881271587.

Hmm, I can help you with the water hardness. Obtain samples, say 50ml, add 10ml ammonia and solochrome black indicator, and titrate with c. 0.01M EDTA. n(EDTA) will equal n(Ca) [a reasonable indicator of hardness]. BenC7 10:32, 7 September 2006 (UTC)

Cyclone/Tornado

I was wondering what the difference between a cyclone and a tornado is.Do cyclones have a funnel like tornadoes do?Andreamiller 10:43, 7 September 2006 (UTC)

This is an ancyclopedia. See cyclone and tornado. The main differences (I believe) are size and duration and the fact that cyclones start over sea. DirkvdM 10:54, 7 September 2006 (UTC)

Thanks,I did actually read both the articles.But my main question was whether cyclones had a funnel or not.Serenacw 10:58, 7 September 2006 (UTC)

No, in the usual sense of the word, a cyclone is a hurricane, which has an eye in the center, not a funnel. However, the word "cyclone" is misused to mean tornado in parts of the US. StuRat 12:02, 7 September 2006 (UTC)

To be fully correct (from cyclone):

Cyclones are responsible for a wide variety of different meteorological phenomena such as tropical cyclones and tornadoes.

So, a tornado is a form of / caused by a cyclone in the formal sense. All cyclones have a rotation, though not all will have "funnels" in the usual sense. And of course, Stu is absolutely correct about colloquial usage tending towards tropical cyclone. — Lomn | Talk 13:26, 7 September 2006 (UTC)

Molecule Diagrams

What are some good programs for drawing 2D molecules (especially organic ones)? What is generally used for Wikipedia? How about 3D molecules? Thanks --Russoc4 14:01, 7 September 2006 (UTC)

See the "Drawing molecules" section above. --Andreas Rejbrand 15:17, 7 September 2006 (UTC)

Oops...sorry. --Russoc4 16:19, 7 September 2006 (UTC)

donations to medical science

I am 80 years of age female (4 children)widow and have had several surgeries. at this time i have 6 incurable conditions in my brain. i think that would make my body a good prospect for worthwhile study. i asked my doctor how to do that and he said my drivers license. surely not! so i am asking help to find out how to donate my body to medical science at my graduation to heaven !

my email is (E-MAIL REMOVED) and my mail address is (ADDRESS REMOVED).

if you cannot help me, please suggest another place at whick i can inquuire for help. thank you

signed.................elaine harbour

Dear Elaine,

I think that your doctor was referring to the "donor" checkbox that many U.S. licenses have on them (in California, it is a little pink sticker; in Massachusetts, it is printed onto the license itself). Each state does it a little differently.

I've Googled around Oklahoma's donor options and haven't found one that works through the DMV though. The two best places to contact might be a company called LifeShareRegistry, which is specifically for organ donation but might know about other donor arrangements, and Oklahoma State University's Center for Health Sciences Body Donation Program. Both of these places could probably point you in the right direction in respects to Oklahoma's specific donor procedures. I commend you on your desire to aid medical science. Thank you. --Fastfission 14:37, 7 September 2006 (UTC)

Of course Elaine thinks she's going to get emailed or written to, so she's not actually likely to come back here (and would probably struggled to find her way back here if she wanted tó, if she's a Wikipedia noob). --Username132 (talk) 18:34, 7 September 2006 (UTC)

So who's going to be the good Samaritan and email her the link to her comment?  freshofftheufoΓΛĿЌ  02:32, 8 September 2006 (UTC)

• I'll do it if I can track down the email adress in the history. - Mgm|^(talk) 07:40, 8 September 2006 (UTC)

This diff. Delete it if you don't need it anymore.  freshofftheufoΓΛĿЌ  12:54, 8 September 2006 (UTC)

Why [is] glass transparent?

fixed by LeyteWolfer 17:08, 7 September 2006 (UTC)

See transparency and glass--Light current 17:12, 7 September 2006 (UTC)

Because if it weren't I wouldn't be able to read this. DirkvdM 18:59, 7 September 2006 (UTC)

And we all know the rules of the universe were written so that Dirk could do what he wants to do, when he wants to do it. ;o) EWS23 (Leave me a message!) 19:23, 7 September 2006 (UTC)

Haha! It's the anthropic principle. -- SCZenz 02:06, 8 September 2006 (UTC)

Indeed. We use glass because it's transparent. – b_jonas 21:11, 8 September 2006 (UTC)

Sailors' Dead WInds

What are the things called where sailors would get stuck with out trade winds for days?

• Perhaps you are referring to the Doldrums? --Nebular110 17:54, 7 September 2006 (UTC)

• Doldrums. LeyteWolfer 17:54, 7 September 2006 (UTC)

No, that's a specific region where that phenomenon often occurs, but the question was for the name of the phenomenon. The answer is at the tip of my tongue, but can't break that barrier so to say. :) Then again, the question is specifically about the trade winds, so that's confusing. Anyway, that excludes the doldrums, because that is the area around the equator where there are no trade winds (if I understand it correctly). DirkvdM 19:11, 7 September 2006 (UTC)

I'd imagine the original poster was probably referring to the doldrums or the horse latitudes. If there's a word for the actual occurence of getting stuck there, as Dirk suggests, I haven't heard of it. EWS23 (Leave me a message!) 19:27, 7 September 2006 (UTC)

I'd say becalmed would be a fairly accurate description. GeeJo ^(t)⁄_(c) • 20:25, 7 September 2006 (UTC)

To be in the doldrums is to be becalmed surely?--Light current 02:37, 8 September 2006 (UTC)

Probably. But to be becalmed is not necessarily to be in the doldrums, particularly if you happen to be 1000 miles away at the time. JackofOz 04:04, 8 September 2006 (UTC)

Handwashing

Can I hand wash clothes using regular (designed for washing machine) detergent, so long as I wear rubber gloves? --Username132 (talk) 18:26, 7 September 2006 (UTC)

I suppose you could, but liquid dish washing detergent works better for hand washing laundry. StuRat 18:48, 7 September 2006 (UTC)

Wouldn't that fade or otherwise damage the clothes? --Username132 (talk) 19:12, 7 September 2006 (UTC)

No, dishwashing detergent is much more gentle on clothes than laundry detergent, and some is even labeled "for use with delicate hand washables". The only concern might be that it would be less effective at removing serious stains, so I'd use a stain spray for that. StuRat 06:04, 8 September 2006 (UTC)

Yes you can, and personally I think laundry should be washed with laundry soap, and dishes should be washed with dish soap, and not vice-versa. :-) Anchoress 18:51, 7 September 2006 (UTC)

I have done that regularly when travelling. I supose it's not too good for the hands, so don't do it too often. Actually, in Cuba I got these areas of hardened skin that the doctor detected when I visited her for something else. It was easily soved with some ointment (can't remember what), but she told me to better not wash by hand. An overcautious doctor, I suppose. Funny StuRat mentions dishwashing detergent, because I use that for everything but my laundry (and my body). So I can now do away with the clotheswashing detergent as well? Less practical for travelling, though because it's a fluid and therefore too heavy. DirkvdM 19:16, 7 September 2006 (UTC)

When traveling, I have used bath soap to wash clothes, and that works okay, too. It also doesn't really require gloves. Marco polo 19:43, 7 September 2006 (UTC)

Couldnt you do it by just having a bath with your clothes on?--Light current 01:41, 8 September 2006 (UTC)

Yes, but you're not going to enjoy the next thirty minutes in the dryer very much.--192.168.1.1 05:19, 8 September 2006 (UTC)

Actually, I met soneone who travelled with one set of clothing who did just that. In the tropics it can be wonderful to walk around in wet clothes. DirkvdM 07:07, 8 September 2006 (UTC)

Portal to define pictures of plants or animals

Hello, is here in the english Wikipedia a Portal to define pictures of unknown plants or animals, like in the german Wikipedia? Greetings --Ruestz 19:00, 7 September 2006 (UTC)

You could also upload to Wikimedia Commons (which is a better place to put photos because from there they can be accessed from any wiki project) and then place them at http://commons.wikimedia.org/wiki/Category:Unknown_species. try to put them in the most specific category you can find. Alternatively, ask at the most relevant talk page. By the way, the word is not 'define' but 'determine'. Wie auf Deutsch glaube ich, 'determinieren', nicht? DirkvdM 19:27, 7 September 2006 (UTC)

Kuiper belt

The article states the majority of Kuiper belt objects were found after 1992, but it does not elaborate on why that is the case. Could someone please answer that, and place it in the article; as I feel the context would be helpful. - RoyBoy ⁸⁰⁰ 19:49, 7 September 2006 (UTC)

I'd speculate its because either:

• The technology required to see them was not yet available

• No-one looked in the right place at the right time with the right telescope

The reasons why someone didn't find/do something before anyone else is usually speculative and thus may be why it isn't in the article. Still, if anyone can source it... Rockpocket 01:31, 8 September 2006 (UTC)

I'd guess the Hubble Telescope, launched in 1990 and upgraded/corrected with COSTAR in 1993, was the source of this new data, as it was a major improvement over Earth-based optical telescopes. StuRat 05:53, 8 September 2006 (UTC)

I suspect that the Hubble isn't used explicitly for KBO surveys—it's field of view is too narrow and telescope time is too precious to go trolling for asteroids. It's possible that some might be discovered serendipitously while examining other objects. The HST can be used for examining these objects in (more) detail once they have been discovered, however. TenOfAllTrades(talk) 12:31, 8 September 2006 (UTC)

David C. Jewitt and Jane Luu discovered the first Kuiper Belt object in 1992 using a telescope in the Mauna Kea Observatory. Looks like people simply started looking for more. One of the larger KBOs, 90482 Orcus, can be seen in photographs from 1951 but nobody noticed it for fifty years (you can't just look at a photo and go "ha, a new planet!" You need to painstakingly compare many photographs from different times and detect tiny movements of very faint blobs to tell stars and moving rocks apart. You need to know what you are looking for.)

In a Scientific American May 1996 article Jewitt and Luu say that since the initial find a bunch of research groups have joined the effort and found a steady stream of KBOs. Weregerbil 08:46, 8 September 2006 (UTC)

When you mention Jewitt and Luu and 1992, you probably mean (15760) 1992 QB1. But that wasn't the first KBO found. As that article points out, Pluto was first, in 1930, and Charon second in 1978. QB1 was the third. -- Plutortalkcontribs 12:08, 8 September 2006 (UTC)

I think there is a distinction between "KBO found and known to be a KBO" and "discovering something which we now consider a KBO but was at the time considered a planet and a moon". --Fastfission 14:50, 8 September 2006 (UTC)

Indeed. In the last fifteen or twenty years there have been several major advances which have made searching for KBOs much easier. The computer hardware and software for automated image analysis (trying to find the one bright speck that isn't a star or known object) has gotten both better and cheaper. CCDs have become much cheaper and much improved in quality, allowing sky surveying without the messy intermediate steps involving photographic plates. Finally, several medium-large aperture telescopes (0.9 meters and up) have been configured for automated sky surveys in the last fifteen years—nobody's been looking very hard for KBOs until recently. TenOfAllTrades(talk) 12:31, 8 September 2006 (UTC)

One lung breathing

In the show Malcolm in the Middle, the character Stevie has (I think) only one lung and breathes a deep breath after every word. Is this medically correct? Reywas92 19:50, 7 September 2006 (UTC)

Stevie is chronically short of breath because he has severe asthma. I can't comment on the medical plausibility of his case, other than to say that if it were a fair clinical picture, Stevie would represent the more severe end of the chronic asthma spectrum.... TenOfAllTrades(talk) 21:50, 7 September 2006 (UTC)

• I doubt that is possible, Reywas92. One long is not enough to provide the body with the oxygen it needs and he would need to be on constant additional oxygen which he's not. - Mgm|^(talk) 07:36, 8 September 2006 (UTC)

Actually, one lung is enough to provide a person with the oxygen they need. Pneumonectomy (removal of one entire lung) is a surgical procedure for treating advanced lung cancer. Patients with one lung are limited to a modest level of physical activity, but otherwise can lead mostly normal lives. They don't need constant additional oxygen and are not confined to a wheel chair, like Stevie. --Ed (Edgar181) 13:07, 8 September 2006 (UTC)

Can guinea pigs eat lettuce?

I read that iceberg lettuce is bad for guinea pigs. Is this true? Reywas92 19:52, 7 September 2006 (UTC)

Iceberg lettuce is pretty low in nutritional value—it's mostly "crunchy water". Neither guinea pigs nor humans get much out of the stuff; we only eat it because it's a convenient vehicle for salad dressings.

In larger quantities, the high water content and (probably) nitrates in the lettuce can cause various sorts of digestive upsets. Small amounts probably won't do any harm, but they're not beneficial either.

Consider something dark green and leafy, instead: kale, dandelion leaves, spinach, clover, or parsley. TenOfAllTrades(talk) 22:00, 7 September 2006 (UTC)

• We used to give our guinea pig nl:witlof. Unfortunately, there doesn't seem to be an English article on the stuf... - Mgm|^(talk) 07:35, 8 September 2006 (UTC)
  • That's Belgian endive. feydey 13:42, 8 September 2006 (UTC)

How can I, as a white man get natty dreadlocks without having to pay for them?

I know that black ppl's hair naturally forms into dreadlocks if they don't brush or wash it for a long time. Is this true for white people too? How long would it take for the dreads to form if I decided never to touch my hair with anything again (it's already past shoulder length)? Some people might say it's gross to never wash your hair but I heard that the hair starts cleaning itself naturally after a while anyway.

I don't want salon dreads. I can't afford them.

It's not whether or not you wash your hair, it's whether or not you comb it. Here's an article called How To Make Dreadlocks and How To Make Dreadlocks - tips. Maybe that will help. Anchoress 21:34, 7 September 2006 (UTC)

Just completely ignore your hair.. I mean wash it and stuff, but don't hair care it, and it will matt. When it's matted just pull the matt into strands as thick as you want your dreads. Philc _T^E_C^I 21:37, 7 September 2006 (UTC)

So can Chinese people get dreadlocks than? It doens't sound right. — [Mac Davis] (talk) (Desk|Help me improve)

Sure, if they have hair that isn't straight. "It doesn't sound right" because you're not used to it, but I'm sure there are at least a few. ColourBurst 18:41, 8 September 2006 (UTC)

I once met a guy who after hiking through the Tasmanian bush for a few days noticed he couldn't get a comb through his hair. So it was either cut the hair or develop dreadlocks. he chose the latter. I believe something similar happened to Keith Richard.

Yup, it's a matter of not combing your hair. I just wonder if you can 'sculpture' the dreadlocks. What if a dreadlock develops you don't like? Some look messy, others look neat, is there a trick to that? And bums nowadays often have dreadlocks, which makes sense, so it doesn't make sense that that would be a recent phenomemon. So did they have them in previous centuries too? DirkvdM 07:19, 8 September 2006 (UTC)

I haven't combed/brushed my hair in years, and I don't have light, straight hair. I also don't generally "treat" it, just shampoo and the monthly conditioner or so. I had a roommate up until a couple of months ago with huge dreads, and although he washed them, I don't think he did very often. Something like, "When I start to smell it too, that's when I wash".  freshofftheufoΓΛĿЌ  07:28, 8 September 2006 (UTC)

Sodium vs sodium chloride in foods

When a food label in the US (FDA regulated) claims sodium content, do they really mean sodium chloride as in traditional edible salt or is this the mass of any digestible form of sodium in the food? As a follow-up, does the human body use sodium or sodium chloride specifically to regulate hydration? When reading over the articles, it's hard to tell if terms are used loosely. p.s. this isn't homework, I swear! --Jmeden2000 21:31, 7 September 2006 (UTC)

As to the first question, my guess is they really mean sodium, but it's just a guess. The second question I can answer a bit more definitively: When sodium chloride is dissolved in water (as it will be in your body) it dissociates almost completely. So what counts is sodium ion, Na⁺; your body has no way of knowing if it was part of sodium chloride or some other sodium salt. --Trovatore 21:39, 7 September 2006 (UTC)

THe main source of sodium in the diet must be sodium chloride. I cant think of any other sodium salts that we eat in any quantity.--Light current 22:24, 7 September 2006 (UTC)

edit conflict: yeah they mean total sodium content, from salt, baking soda preservatives etc. because it's all sodium in the end. the sodium ion is important, for example in the Na+/K+-ATPase. not to say chloride isn't important too. and i think they measure sodium due to its role in heart disease, but i'm unsure. Xcomradex 22:29, 7 September 2006 (UTC)

and just for light current: sodium bicarbonate, sodium benzoate, monosodium glutamate... Xcomradex 22:29, 7 September 2006 (UTC)

Apart from monosodium glute a mate (used as flavor enhancer). How much sodium bicarb and sodium bezoate do we eat?--Light current 22:33, 7 September 2006 (UTC)

• sodium benzoate: FDA maximum of 0.1% w/w
• sodium bicarbonate: from cookbooks seems about one teaspoon (5g)/ cake

bear in mind we don't usually put a lot of salt on meals in w/w terms. but is still probably the major source, due to its ubiquity. Xcomradex 23:08, 7 September 2006 (UTC)

1gm NaCl contains 0.4 gm sodium--Light current 23:31, 7 September 2006 (UTC)

it does, but remember we don't put 1g salt on a 100g steak. Xcomradex 01:06, 8 September 2006 (UTC)

I dont put any on. But there again I dont eat steak.--Light current 01:08, 8 September 2006 (UTC)

By the way, the unit sign of "gram" is g. gm is "mostly obsolete" when referring to grams, unless you were actually talking about giga-meters.  freshofftheufoΓΛĿЌ  02:24, 8 September 2006 (UTC)

THanks for that 8-)--Light current 02:25, 8 September 2006 (UTC)

Sodium is what's used for hydration. Chloride is the most important anion in the body because it is the most common. However, the sodium is what's regulated and the chloride usually just follows! InvictaHOG 09:56, 8 September 2006 (UTC)

Follow up

First of all thank you to all who answered, this has been most informative. I would like to add another sub question: how do you suppose all animals developed a heavy reliance on sodium if it is so rare to occur in plants? (as per the sodium article). Surely primitive mammals were not digging salt mines or evaporating sea water... So where in the food chain does it all come from? --Jmeden2000 17:22, 8 September 2006 (UTC)

Salt lick. --Serie 19:34, 8 September 2006 (UTC)

Mutism

I recently watched a TV drama in which one of the main characters got in some kind of accident and lost her hearing. She chose to start using sign language exclusively because she couldn't hear the sound of her voice and was ashamed about the way she assumed it would sound. That said she did talk occasionally during the show, with a very nasal voice, the kind one might usually associate with a person unable to hear from birth. I'm not sure how realistic the drama is supposed to be, but I'd be a little shocked if there was such a big misconception as that. Do (could) people who become deaf (suddenly?) lose the ability to speak in a fashion that they were able to before they became deaf? I couldn't find any mention of it at speech disorder or deaf culture.  freshofftheufoΓΛĿЌ  22:21, 7 September 2006 (UTC)

I've heard radio-interviews with people who lost their hearing and their speech was completely 'normal' and melodious to my ears. Singing, where the frequencies and modulations have to be more accurate, is a different thing; I distinctly remember listening to a woman who had lost her hearing years ago sing Amazing Grace, and it was hard to recognize the melody. Percussionist Evelyn Glennie almost entirely lost her hearing at the age of twelve and speaks like a hearing Scottish person too, as can be heard in the documentary film Touch The Sound. ---Sluzzelin 05:59, 8 September 2006 (UTC)

The problem with that, I guess, is that deafness usually isn't absolute, and at least some of the people you mentioned might have some awareness of the sounds coming from inside their bodies (Evelyn Glennie's article notes that she has "very limited hearing"). Failing that, it seems that at the very least it may not be expected for someone to lose the ability to speak properly along with their hearing, though I wonder if there are exceptions. I actually quite liked the drama so I kind of want it to not be a complete farce!  freshofftheufoΓΛĿЌ  07:11, 8 September 2006 (UTC)

This is also why singers (and instrumentalists for that matter) need feedback through a monitor on stage. If they can't hear their own voice they can't sing in tune. I wonder if classical singers before a full orchestra (which can be a lot louder than a rock band) use this too. I don't recall ever seeing it. DirkvdM 07:25, 8 September 2006 (UTC)

No they dont. THey can belt it out at much higher levels than pop singers so they can hear themslves ok. Also the orch tends to come down under the singer a bit.--Light current 07:38, 8 September 2006 (UTC)

(Edit conflict) You're right. And a further difference to the TV drama, is that most people lose their hearing gradually, allowing them to closely monitor and correct changes in their speech. Googling "traumatic mutism" or "post-traumatic mutism" leads you to some neurological websites discussing this phenomenon. In the cases I found, mutism was explained psychologically and not linked to the loss of sense of hearing.---Sluzzelin 07:34, 8 September 2006 (UTC)

Ok ok, but I'm losing the original question. I don't think there was any post-traumatic mutism or anything like that, the show explained her "nasal speech" to the extent that it was only a concequence of her loss of hearing, which in turn was caused by some sort of car accident I think. Anyway, I think it's pretty clear that this drama was a little bit scrubbier than I initially thought. Loss of tone recognition doesn't really explain either why she would suddenly sound nasal. Oh well, thanks guys!  freshofftheufoΓΛĿЌ  12:03, 8 September 2006 (UTC)

September 8

How large are the Mars rovers?

I'm curious to know the dimensions of the Opportunity and Spirit Mars rovers. I can't seem to find these specs on the Internet. Thanks!

Cruise vehicle dimensions: 2.65 meters (8.7 feet) diameter, 1.6 meters (5.2 feet) tall Rover dimensions: 1.5 meter (4.9 feet) high by 2.3 meters (7.5 feet) wide by 1.6 meter (5.2 feet) long

Weight: 1,062 kilograms (2,341 pounds) total at launch, consisting of 174-kilogram (384- pound) rover, 365-kilogram (805-pound) lander, 198-kilogram (436-pound) backshell and parachute, 90-kilogram (198-pound) heat shield and 183-kilogram (403-pound) cruise stage, plus 52 kilograms (115 pounds) of propellant

From mars tv. Also, check out Mars Exploration Rover ---Sluzzelin 06:51, 8 September 2006 (UTC)

Useful fictions inside of science

What are some useful fictions that have been created for calculational purposes similar to a center of mass/gravity? A center of gravity isn't an actual feature of matter, just something we impose upon matter in order to help make our calculations easier for a given system. Thanks--droptone 12:32, 8 September 2006 (UTC)

See WP's articles on mathematical models in physics, and on theory. ---Sluzzelin 12:48, 8 September 2006 (UTC)

That reminds me of a joke my boss once told me about calculating the surface area of a chicken. First you assume that it's a perfect sphere... – ClockworkSoul 12:53, 8 September 2006 (UTC)

I remember this book: Consider a spherical Cow was quite popular a while back.---Sluzzelin 13:05, 8 September 2006 (UTC)

Depends how broad you want to make you definition of fiction. You could say that energy and entropy are useful fictions, since you can't measure them directly - you have to infer them from other properties of an object or system. And temperature, pressure, density and viscosity are all average measures that only make sense for a large population of atoms or molecules, so you could argue that they are also fictions. Velocity depends on your frame of reference, so maybe that is a fiction too. In fact, the only properties that are truly "features" of elementary particles seem to be spin, charge and mass. Gandalf61 14:45, 8 September 2006 (UTC)

• Newtonian physics is technically wrong, in that it doesn't account for relativity, but still widely used for most calculations.

• The Dalton model of the atom, while useful for basic chemistry, is not as useful in particle physics.

• Planetary and lunar orbits are approximated as ellipses, while the true orbits must account for various perturbations.

StuRat 19:35, 8 September 2006 (UTC)

Body Mass Index assumes every human has an identical body shape, but is effectively used to determine obesity. While it could be improved by using body shapes or even getting an extremely accurate BMI by weighing people in water, the difference between BMI and the highly accurate indexes is statistically insignificant for nearly all people. --Kainaw ^(talk) 20:12, 8 September 2006 (UTC)

Help to identify spider

Hello, can someone please tell me what spider this is? Or at least if it is poisonous? Sorry for the bad pic but I only had my cellphone camera available at the time. I live in Gauteng, South Africa. I am afraid for my children's safety. The spider is about as big as a toddler's hand. One enters our house every week or so. If I wave an object like a broom near it, it raises its front legs (?) towards the object. Is this a defensive or aggressive pose? Sandman30s 14:13, 8 September 2006 (UTC)

That picture really isn't very much to go on. I believe, in general, that when a spider raises its front legs it is generally an aggressive, "Look at my teeth" pose, but I only know about Australian spiders in that respect. This page contains pictures of some of the more "medically important" spiders of South Africa that you can compare it with. Apparently South Africa also has trapdoor spiders and baboon spiders, neither of which would be very fun to get bitten by. Again, I'm not a spider expert in any respect, though. If I had to guess by the picture alone, the long-legs, big-head would make me worry that it was a violin spider, which have poisonous (but not always deadly) bites. I would definitely try to kill it in any case—a shovel would be my method of dispatching it, personally. --Fastfission 14:43, 8 September 2006 (UTC)

Thanks very much for the detailed answer. My best guess from all those pictures is the lesser baboon spider (HARPACTIRELLA), it doesn't look like the violin spider due to a different colour, unless the violin is also dark brown with dark red and black legs. I will try to get a better pic the next time, sorry. Also if the spider is not poisonous, I would not like to affect the ecosystem around the house, as the spiders would reduce my overpopulation of crickets :)

I'd much rather have the crickets. :-) StuRat 19:21, 8 September 2006 (UTC)

Not to be too much of a pedant, but all spiders are venomous. I have no idea whether this particular spider is dangerous, however. --Ginkgo100 ^{talk · e@} 20:18, 8 September 2006 (UTC)

Are you sure? I remember that that was some sort of urban myth. I'd check Snopes if I had the time. - Mgm|^(talk) 20:45, 8 September 2006 (UTC)

Correction to the above from spider: there are a few species not able to inject venom. --Ginkgo100 ^{talk · e@} 20:23, 8 September 2006 (UTC)

Looks like a "jagspinnekop" (Palystes sp. - African hunting spider), especially as you mention the striped legs, and the very typical raising of the front legs when threatened. The raised legs are impressive, but only a show - it does not attack that way. It hunts at night, and has no web as such, just a nest which takes 2-3 days to build. Though one cannot judge size, it looks like a youngster you have there (inter alia it still has 8 legs!). Also called a "reënspinnekop", (rain spider) from it's alleged habit of appearing inside when rain threatens. This spiders's bite hurts like a bee-sting, but won't kill - unless you get a heart attack from fright. It normally runs away - very fast once it starts running - to a dark corner somewhere. If you have trees outside (or dense bushes or ivy on a wall) you may find its large fist-sized nest of leaves, twigs and silk hanging inside the denser growth - be cautious, the female guards the nest. I leave them be, they don't build nests inside your house, and I've watched them catch other goggas inside at night. They definitely eat crickets, but there is no way they will prevent the periodic "cricket epidemics". If you wish to catch it, it is legal to keep it, and you can handle it if you don't mind an occasional bee-sting-bad bite. Contact a museum to find the correct diet, etc. The site also gives advice on how to catch it and return it outside. I normally use a plastic shopping bag which I place over it and then coax it into the bag, trying not to hurt the legs, then leave the bag open in a tree. The "bobbejaanspinnekop" (Harpactira/ella you mentioned - Therasophidae - Baboonspider) is bulkier, legs relatively shorter and oriented differently, more hairy, does not show the clear markings you mention, does not typically show that same threatening stance, and is a protected species, because of a demand as "pets" in the first world countries. Searching the web for "rain spider" or "hunting spider" should give the best results if you want to know more. --Seejyb 20:55, 8 September 2006 (UTC)

diabetes in cats

Can someone please advise what choices for cats are available? My vet is at a loss as to bringing down the insulin level. i've tried humulin u, humulin m, and nothing works. i'm getting pretty desperate.

Try feline diabetes and the wiki on pet diabetes for further links and references. Please understand that we can't give medical advice at the reference desk. Good luck and all the best to your feline friend. ---Sluzzelin 14:55, 8 September 2006 (UTC)

ribose sugar

Is a ribose sugar a reducing sugar

Look at the structure of ribose and see if it contains the substructures or other features that are consistent with those of a reducing sugar. DMacks 15:10, 8 September 2006 (UTC)

Paraffin lanterns & alcohol

Would it be possible to safely run a paraffin lantern on alcohol if you haven't got any paraffin handy? If not what could you run it on that doesn't need to be obtained from hydrocarbons. AllanHainey 15:35, 8 September 2006 (UTC)

Paraffin is a solid hydrocarbon while ethanol is a liquid alcohol. Because it's not really the solid wax of paraffin that burns, but rather the resulting liquid/gas, if your lamp can accomodate a liquid fuel, it may be able to run properly.--Russoc4 17:47, 8 September 2006 (UTC)

In the UK, paraffin is a liquid fuel, and paraffin wax is a solid - the constituent of candles. --G N Frykman 17:54, 8 September 2006 (UTC)

Forgot about that...well, ethanol may or may not work properly. I found a very indepth page [27] describing and comparing many fuels that can be used in camping stoves. The same applies here, only the fuel has to travel through a wick. The only problem I can forsee with ethanol is that it boils relatively easily. It's also less efficient when comparing BTUs/lb. isopropyl rubbing alcohol is not recommended. --Russoc4 19:04, 8 September 2006 (UTC)

I'd tend to recommend strongly against the use of ethanol in a lantern. Ethanol burns with a hotter, bluer flame that doesn't generate much light and will be harder on your lamp hardware. In addition, it has a higher vapour pressure (meaning that heating it during lamp operation may result in various sorts of failure of your lamp, some quite dramatic) and lower flashpoint. TenOfAllTrades(talk) 21:15, 8 September 2006 (UTC)

Burn!!

It's my understanding that when you burn organics like wood, or sucrose, the impurities of water and smoke components are burned off leaving residual carbon behind. If this is true, why does this residue not continue to burn? Doesn't carbon oxidize to form CO2? --Russoc4 17:42, 8 September 2006 (UTC)

See charcoal--Light current 17:44, 8 September 2006 (UTC)

Many people confuse heating and burning. See destructive distillation. --G N Frykman 18:00, 8 September 2006 (UTC)

Soot – which is mostly carbon – is the result of incomplete combustion of organic matter. As long as the fire remains hot and well-supplied with oxygen, the carbon will burn off to form carbon dioxide. (Under conditions of inadequate heat or oxygen, you may instead end up with carbon monoxide.) TenOfAllTrades(talk) 18:09, 8 September 2006 (UTC)

So charcoal/coke is made by "heating" wood/coal, but not actually burning it completely in enough oxygen. I get that part. You didn't answer my question. What I don't get is that when wood burns completely, it creates ash, which glows for some time, but then dies out. Why does it not burn if it's mostly carbon? --Russoc4 18:51, 8 September 2006 (UTC)

Burning an organic material oxidizes it, leaving oxides of its component elements, the most common elements in organics are carbon hydrgoen and oxygen. I there is insufficient oxygen, you will be left with unoxidized elements. So hydrogen and carbon, you are unlikely to notice any hydrogen, and carbon is in the form of soot. Carbon needs the heat from the fire to form new bonds with oxygen, so will not spontaneously oxidize once oxygen is sufficient, so it will be left. Philc _T^E_C^I 21:04, 8 September 2006 (UTC)

Aldol Compound

Can anyone help me out on this one? I'm trying to figure out the name of this compound that results from an aldol reaction. It is a yellow solid with a molecular formula of C₁₈H₁₆O₃, and its experimental melting point is 167°C to 172°C. ChemFinder is no help either, unless I'm not looking in the right spot. --Russoc4 20:05, 8 September 2006 (UTC)

File:Aldol.PNG

• Try if you can get your hands on a book like the Handbook of Chemistry and Physics, BINAS or if you happen to be able to read Dutch the "Chemiekaarten". I would also recommend you draw up the different compounds that could result with that molecular formula and make a guess at which it is by determining whether long chains have a lower/higher melting point and how saturation affects it. - Mgm|^(talk) 20:51, 8 September 2006 (UTC)
• If you do the guessing well it will reduce the number of compounds you need to look up. - Mgm|^(talk) 20:53, 8 September 2006 (UTC)

I considered the Handbook. If I have to, I'll use it. Thanks though. --Russoc4 21:00, 8 September 2006 (UTC)

American passenger rail profitability

Why is it that, despite the commercial viability of passenger railways in Europe and Japan, American passenger rail has never turned a net profit since 1930, four decades before the founding of Amtrak? C. M. Harris ^{Talk to me} 20:09, 8 September 2006 (UTC)

Gasoline is far cheaper in the U.S. than in every European country I've been to (Norway, Sweden, Denmark, U.K., France, Italy, and Turkey). I assume it is cheaper than all of the European countries. While we complain about $3/gallon gas, a friend of mine in Italy is complaining about $10/gallon gas. Since gas is so cheap, there is no incentive for people in the U.S. to use the railroad, which even with the cheap tickets is still not much cheaper than driving. So, if ticket prices were increased to allow the rail to profit, nobody would want to ride. --Kainaw ^(talk) 20:21, 8 September 2006 (UTC)

What does "commercial viability" mean? I thought most non-US rail systems were government-subsidized... DMacks 20:37, 8 September 2006 (UTC)

Most rail systems are subsidised, as a lot of countries recognize the rail service not as a gold digging source of income for the government, but as a service, which the government helps provide, in exchange for all the taxes etc. Philc _T^E_C^I 21:00, 8 September 2006 (UTC)