Wikipedia:Reference desk archive/Science/February 15-21 2006

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February 15[edit]

Important person in medicine[edit]

Who proved that fever was not a disease but a sympton of disease? i gotta poop Thanks for taking your time to try and answer my quesion.


Perhaps Foreigner (band) ? [1] :-) StuRat 00:49, 15 February 2006 (UTC)
I'm not sure, but if someone finds out it would be great if they could add the information to our article about fever. Perhaps a 'history' section, or just a note in the article intro. TenOfAllTrades(talk) 05:45, 15 February 2006 (UTC)

What are storage devices?[edit]

No Question

Try looking at storage device. --Kainaw (talk) 01:02, 15 February 2006 (UTC)

Viewing Venus (Morning Star) with Binoculars[edit]

I was looking at the planet Venus February 12 with my 8 power birding binoculars. I thought I was seeing the cresent shape of it, with the bright part directed at the sun. Question: is it possible to resolve, i.e., see the round shape of Venus with such low power optics?


Yes, it is. According to the article on phases of Venus, some people have even seen the phases with their naked eyes. Human eyes have a resolution limit of around 1 arc-minute, while the angular diameter of Venus is slightly larger. If you multiply Venus's angular diameter by 8, you'll get approximately 482 arc-minutes, which is about one fourth the Sun's angular diameter. --Bowlhover 03:35, 15 February 2006 (UTC)
I'm multiply a number slightly larger than 1 by 8 and get 482 ? And isn't 482 arc-minutes equivalent to over 8 degrees ? That's huge. StuRat 05:51, 15 February 2006 (UTC)
Well, if you multiply 1 arc-minute times 8, you get 8 arc-minutes, which is approximately one-fourth of 30 arc-minutes, the angular diameter of the sun. Perhaps that is what Bowlhover meant? — Knowledge Seeker 07:48, 15 February 2006 (UTC)
8 arc-minutes is around 480 arc-seconds, so I assume this is what Bowlhover meant. — Asbestos | Talk (RFC) 16:40, 15 February 2006 (UTC)
Yea, that must be it. StuRat 20:50, 15 February 2006 (UTC)
I don't know why I'm so careless. Yes, I meant 482 arc-seconds, not 482 arc-minutes. --Bowlhover 23:16, 15 February 2006 (UTC)

Thank you for the answer. I went to the reference on the Phases of Venus as well. Rogelio

Echo In My Head[edit]

Within the last 3 months I have noticed that when I click my teeth together I sense an echo in my head. When I tap a finger on my head I also hear the same thing. I can tap all over the front, right side and rear of my head and hear it. It is not noticeable on the left side of my head. I asked my dentist about it and was told it was probably my sinuses. I asked my doctor about it and he had no idea. I am 68 years old and in good health. I am very active and have not noticed any other changes in my body. Any ideas?

Perhaps a CAT scan or MRI would be in order ? Based on your age, you might have lost some bone mass and have an enlarged sinus for that reason. If so, you should know about it, as your skull might be more fragile than it once was, and perhaps some diet changes and/or nutritional supplements might be in order. Do you having any other signs of bone loss, like a decrease in height ? StuRat 05:30, 15 February 2006 (UTC)
What you describe sounds like the phenomenon known as "autophonia", where there is a perceived increase in resonance from one's own voice and other body sounds. This is often the result of some middle-ear condition. Too bad your physician was too quickly dismissive; you might ask him whether a referral to an otolaryngologist might be appropriate...--Mark Bornfeld DDS 13:55, 15 February 2006 (UTC)
Article abstract on autophonia - Cybergoth 04:36, 18 February 2006 (UTC)
It's happened to me when I have water in my ear, but it goes away within a day, and I am not your age, so i dunno M@$+@ Ju ~ ? 23:55, 15 February 2006 (UTC)

Who invented the IV?[edit]

Who invented the IV?

I heard somewhere that a black man invented the IV? Is this true? What was his name? I want to get this confirmed for Black History Month and Google is not helpful at all. Nick 04:13, 15 February 2006 (UTC)

Good question. This seems like an easy enough question, but the obvious google searches don't turn up anything right away.
I've got two sources ([2], [3]) saying that the hypodermic syringe (at least in a form we'd recognize today) was invented in the mid-1800's, probably by Pravaz in Lyon in 1853. Still looking for references for the longer-duration implanted IV. Steve Summit (talk) 05:17, 15 February 2006 (UTC)
I thought he was asking if a black man invented IV. Sigh.  freshgavinG???  05:26, 15 February 2006 (UTC)
Har. (Don't you know you can get in trouble four being too cute?) Nick: a google search for "intravenous therapy" and "history" is somewhat more promising, and turns up a 1996 article by D. Millam called "The history of intravenous therapy", but so far I've found only this citation; finding the actual article text might require a trip to a medical library. Dunno why there's so little information on this. I think I remember reading it was a black man, too. Steve Summit (talk) 05:47, 15 February 2006 (UTC)
No one can glean the name of the inventor? Nick NickDupree 08:30, 15 February 2006 (UTC)
Ok we've got it down to 'intravenous', not the Roman '4', Current-Voltage, a Led Zeppelin album or any other of the other meaning given in IV. Now for the obvious question 'Intravenous What'? Drug use? Assuming that must have been a black guy sounds pretty discriminating to me (could as well have been a woman). Or just 'sticking a needle in your arm' in general? This site gives various options. DirkvdM 14:00, 15 February 2006 (UTC)
This is probably a mangled reference to Charles Richard Drew and the history of blood banks. Rmhermen 19:40, 15 February 2006 (UTC)
YES! That's it! Thank you!! Nick NickDupree 22:40, 15 February 2006 (UTC)
Mr. Balboa invented it - there's a documentary film about it all, it's called Rocky IV.
Slumgum 01:49, 21 February 2006 (UTC)

The Romans had a needle like object that was meant to preform eye surgery bye sucking the lens from the eye in what would be recongnized now as a Hypodermic Needle.

Intentionally getting viruses[edit]

I've been wondering for quite a while, if someone for some reason wanted to have their computer severely messed up, are there sites out there that a person can go to to intentionally get viruses? What is the easiest way for a person to screw their computer up via the internet? (exluding physically smashing it or other direct physical ways)

Install Windows. -zappa 16:49, 22 February 2006 (UTC)
Let me remote control your computer and I'll delete as many important system files as I can. I'm serious--deleting important files is what many viruses do, and if you want to screw up your computer without smashing it, delete all the files you can. I find that deleting critical files is easier with Linux systems than with Windows systems, but that may only be because I know more about how Linux works than I do about how Windows works. --Bowlhover 05:11, 15 February 2006 (UTC)
Go to as many pron sites as possible. - Akamad 07:04, 15 February 2006 (UTC)
In the time it takes to search the Internet for viruses, you could have just written one yourself. In fact, take this line of destructive Windows command prompt code completely free of charge from me:
del /f %systemroot%
There you go! You've practically destroyed your Windows computer now! Disclaimer: DO NOT RUN THAT LINE OF CODE. It is irreversible, and you should only run it if you want to screw up your computer for good. But that was the question, I suppose. -- Daverocks (talk) 09:04, 15 February 2006 (UTC)
Can't the computer be 'fixed' (after running that code) just by formatting the hard drive and then installing windows again? Flea110 03:19, 16 February 2006 (UTC)
Well, it is screwed up from an informational point of view -- all that was there would no longer ber. From a physical point of view, it is still technically fine, though that fact wouldn't be of much help to most people. --Fastfission 19:18, 17 February 2006 (UTC)
System files aren't really that important. You can bugger things up, but it can be fixed. If you really want to emulate the nastiest viruses delete your work files. Actually deleting won't do the trick. Get yourself one of those erasing programs that overwrites the disk space several times with junk, then let it loose on that novel you've been working on for the last six months. Obviously for maximum dispair you should physically destroy any backups you have, but this is beyond the capability of a virus so it's cheating. Unless of course you don't backup your important files in the first place. Lots of people don't. In fact I reckon most people don't until they learn the hard way that they have too. Theresa Knott | Taste the Korn 09:13, 15 February 2006 (UTC)
I always thought del can't delete recursively, and that's what the deltree command was for. But I might just be stuck in the DOS-world. – b_jonas 12:13, 15 February 2006 (UTC)
Actually, you're completely correct, I forgot about that. I wasn't planning to test my code out though, hehe :D -- Daverocks (talk) 08:31, 16 February 2006 (UTC)
Google however says that deltree is now obsolate and del has a /s switch to operate recursively. – b_jonas 17:44, 16 February 2006 (UTC)
Just turn off the firewall and leave the computer on. According to some recent statistics, you should have a virus (a worm, actually) in half an hour or so on average. [4] A fresh install of an old version of Windows, with no security patches applied, works best for this.
If that's not enough, go online with an old version of IE and look for porn sites. Turn the security level for the Internet zone to minimum. Also post your e-mail address all over the net and read all the mail you receive with an old version of Outlook Express. —Ilmari Karonen (talk) 09:31, 15 February 2006 (UTC)
The viruses you get from the Internet (because you don't have a firewall or anti-virus software) really aren't that destructive. One of my Windows computers, for example, didn't even have a firewall or anti-virus software installed. After a few years, I scanned it using Stop-sign and Stop-sign found more than 600 threats, with 100+ being viruses/trojans. I just continued using the computer until it fell on the ground and its hard disk cracked--I didn't notice any difference in its speed while it was working. --Bowlhover 21:21, 15 February 2006 (UTC)
The viruses you get from the Internet really aren't that destructive
That depends on how you define 'destructive'. Over the past few years, viruses are being written more to steal than to destroy. Your virus destroys someone's computer, worst case, they reformat and lose all their photos and music. No particular benefit to the virus writer, other than a twisted sense of pride in causing destruction, and a possibly pissed-off user coming after them with a pitchfork. Now, if you write a virus to steal credit card numbers, passwords and the like... you can actually make money! Plus, in this case, it's not in your interest to disable the computer, you want to keep it running for as long as possible to maximise the 'take'. Or, you write a virus to turn the computer into a zombie under your control, so you can use it to spam to your heart's content, or launch DoS attacks against a casino's website, hold them to ransom and make even more money!
The point I'm trying to make is that just because your computer wasn't really slowing down doesn't mean that the viruses on it weren't causing damage. The nature of viruses is changing, but they are just as destructive as ever and should be fought just as diligently. — QuantumEleven | (talk) 13:52, 16 February 2006 (UTC)
I define "destructive" as the ability to destroy, not the ability to steal information. I'm not saying that spyware should be ignored, because they shouldn't. I'm just saying that turning off your firewall/anti-virus is likely not going to screw up your computer. It's a bad idea though. --Bowlhover 04:14, 17 February 2006 (UTC)
Whatever happened to real viruses, written in assembly language? For example, terminate and stay resident boot sector viruses could make a disk unusable and unformattable. ᓛᖁ♀ 03:49, 16 February 2006 (UTC)
They're not profitable, and they don't last that long. Analogies between ebola and aids - one is deadly but rare, the other takes years to kill (indirectly) but it much more prevalent. Tzarius 04:42, 16 February 2006 (UTC)
I think there's a lot of confusion here about what is just malicious code and what is a virus. A virus is code which self-propagates; it may or may not tamper with system files or delete files or anything like that. Most of the really impressive ones as of late did not too much more than turn ones computer into a virus-sending machine. So simply deleting files from another computer is not really replicating virus behavior -- if there's no transmission, it's not a virus (in terms of medical analogies, it would be something like a cancer). --Fastfission 19:18, 17 February 2006 (UTC)
Though cancer might be a better term, I believe non-transmitted computer viri are called bacteria. Superm401 - Talk 08:06, 20 February 2006 (UTC)

Ghosts and haunted places[edit]

What is the criteria for considering a place "haunted"? The article about ghosts says: 'They may wander around places they frequented when alive or where they died. Such places are known as "haunted";' However, nobody considers my house to be haunted, yet I'm sure that at least one person died here. I mean, humans have been living on this land for...a long time (each country has its own "earliest human habitation date", and I don't want to reveal where I live). What are the chances that nobody, in all these years, has died where my house is now? What are the chances that nobody (who is now dead), in all these years, has spent their entire life here? Why is my house not considered haunted, and why isn't every house in the world considered haunted? --Bowlhover 05:01, 15 February 2006 (UTC)

I think the people who believe in that type of thing say that only a small portion of the dead actually haunt a place, and usually only for a few centuries. Apparently they get bored and move on. StuRat 05:11, 15 February 2006 (UTC)
That's a problem that a lot of fortune tellers (aura readers) need to answer up to as well. They always end up saying stuff like "you were a squire in a previous life" or even more rediculously "you were Joan of Arc in a previous life" when in reality, somewhere close to 99.9999% of all humans that ever lived were complete bums, and totally not interesting. If you were somebody in your previous life, you probably have less than a 1:10000 chance of having been richer than you are now. The Hindu faith explains this better, with people being reincarnated as snakes and flies (hopefully, their aura readers are as honest). As an answer to your question, I always assumed that the reason my house wasn't haunted, is because all the people that died in it were good people and went to heaven. Mind you, I don't believe that anymore : ).  freshgavinG???  05:58, 15 February 2006 (UTC)
You know, I can't help noticing that there are more people now than there used to be. A lot more. In fact, we're fast approaching the day when there will be more people alive than ever lived before in all history, if we can expand outwards into space and keep our birth rates up. So, how do reincarnation advocates explain this curious influx of new souls? Are all the grasshoppers living better lives and moving up in the hierarchy? Black Carrot 13:16, 15 February 2006 (UTC)
Actually the number of dead people increases at about the same rate as the number of live people, so the ratio remains at about 7% of all the people who have ever lived being currently alive at any given time. StuRat 20:42, 15 February 2006 (UTC)
Yes, that's right. The theory is that every life form is reincarnated into a higher life form. Plankton become grasshoppers, grasshoppers become dogs, dogs become humans, and humans become money. JackofOz 13:22, 15 February 2006 (UTC)
Well, if I really was a squire (or Joan of Arc) in my previous life, I certainly don't remember anything about it. I do experience a lot of Déja vecu's, but they're usually about things that I wouldn't have seen in my "previous life". --Bowlhover 20:28, 15 February 2006 (UTC)
Also, according to wiki the average rate of population increase has been decreasing (a negative jerk, if you may) so I don't think we'll have to worry about outnumbering the dead by that much. Deja vus are cool though.  freshgavinG???  15:28, 17 February 2006 (UTC)

Are Microsoft products intelligent design or just evolution ?[edit]

I would be glad to find a definitive answer. Ta.

Unintelligent design. -zappa 16:51, 22 February 2006 (UTC)
Neither. Evolution is a process by which organisms develop, and Intelligent design is an attempt to offer an alternative interpretation of that process. Microsoft products are not organisms, so using the terms ID or evolution for the development of those products will be only a metaphor. David Sneek 08:54, 15 February 2006 (UTC)
Blatantly intelligently designed - they have about as many faults as the 'intelligently designed' human body, which has an appendix, retinas that are inside out, and a non-functional tail. Obviously, only an 'intelligent designer' could hash things up so badly. ;-) — QuantumEleven | (talk) 09:27, 15 February 2006 (UTC)
The inside-out retinas however have the advantage that they can be supplied with blood easily, so I wouldn't count it as a design bug. – b_jonas 12:10, 15 February 2006 (UTC)
I don't know about you, but my retinas crash just about everytime I update my optic drivers-- 23:24, 15 February 2006 (UTC)

Image program question[edit]

Is there a command-line program for Linux that will take a JPG image, and instead of actually showing it, output information about its properties, such as width and height? JIP | Talk 08:31, 15 February 2006 (UTC)

Yes. jpeginfo. Notinasnaid 08:43, 15 February 2006 (UTC)
Some Google searching also turned up this website [5], which mentioned $ identify <image_filename> will probably spit out what you're looking for. And if it doesn't, then $ identify -verbose <image_filename> almost certainly will. --PeruvianLlama(spit) 08:50, 15 February 2006 (UTC)
"identify", incidentally, is part of ImageMagick, which lets you do all kinds of things to images from the command line. -- Finlay McWalter | Talk 00:48, 19 February 2006 (UTC)

Question Regarding Radio source SHGb02+14a (SETI@home finding)[edit]

From the article Radio source SHGb02+14a: In the three times it has been detected, it has doppler shifted quite rapidly. This is presumably due to the motion of the source itself relative to us. A shift of 37 hertz per second (the maximum observed) would mean that the source was accelerating at around 8 m/s². If the civilization was sending out a signal from a home planet in orbit around the Sun, this would imply a pretty rapid rate of rotation. The Earth's acceleration about the Sun is much less.

With the understanding that I know very little about science and have an active imagination - has anyone given any consideration at all to the idea that the signal may come from an artificial body - a spaceship or a probe, basically? 8 m/s², unless I'm mistaken, is pretty close to acceleration due to Earth's gravity, the equivalent of 1 g; pretty reasonable for an artificial body containing human-style organic life. Does anyone know anything else about this signal, or if the possibility has even occured to anyone? Thanks for your time. --Brasswatchman 09:06, 15 February 2006 (UTC)

I'm sure someone has thought about that, yes. However, IMO this is a good occasion to invoke Occam's Razor - what is the simpler explanation for what we're seeing? We're seeing a radio source that's accelerating. It could be natural or artificial. Your argument that 8 m/s² is pretty close to Earth's gravitational acceleration is not bad, but don't forget that while Earth has a gravity of 9.81 m/s², that doesn't say squat about the necessary gravitation for extraterrestrial life, in other words, just because we evolved in 1g doesn't mean that it's necessary for life. As a converse example, Mars, a place where we could well imagine life may have evolved (the jury is still out on whether it has or not), has a gravity of 3.7 m/s². Plus, let's assume that this is some kind of artificial probe or spaceship - why would it be accelerating at 8 m/s²? I'm sure you were thinking of some form of artificial gravity on board, but there are other ways of generating artificial gravity (such as spinning the ship). Also, the source has a maximum observed acceleration of about 8 m/s², it's not constant. If it was some kind of probe or ship, that would mean it was constantly speeding up and slowing down. Sounds a bit wasteful to me.
But all this is just speculation, the result is: just because this source is accelerating at 8 m/s² doesn't say anything about whether it's artificial or natural. Plus, the article is somewhat misleading - there are plenty of natural sources of radio waves, radio signals do not automatically imply that someone is sitting on a planet with a big transmitter. There could well be an object in a close orbit around a star (such as those super-Jupiter planets we've been finding in other solar systems, see Extrasolar planet) which orbit so quickly to account for the perceived acceleration (we would perceive it as such if the object's orbit were about edge-on to our line of sight), and we know that our Jupiter dumps out enormous amounts of radio waves, so these super-Jupiters could do so as well.
Long answer, short summary: unless we get more information indicating that this source is not natural, it looks like this is probably a seriously funky piece of astronomy, but most likely natural. — QuantumEleven | (talk) 09:22, 15 February 2006 (UTC)
In future, remind me to read the article before I answer! :) It appears the signal is highly erratic, seeming to accelerate at different rates, and emanating from a region of space without any known star systems. It sounds like a glitch - don't forget that radio telescopes are fantastically sensitive instruments and pick up all sorts of things which can be difficult to interpret. I can see why this could look like a signal from ET, but read the Planetary Society's entry on this - for many reasons, it doesn't match what a signal generated by an artificial source should look like. Keep your ears open about further developments on this, but it strongly looks like a glitch of some sort. — QuantumEleven || (talk) 09:41, 15 February 2006 (UTC)
Regarding the use of such acceleration, I was less thinking of artificial gravity as I was of the fact that 1 g acceleration is considered pretty comfortable for humans / Earth-style organic creatures. I can't seem to find this information on Wikipedia, but if I remember correctly, I believe that humans can take about 10 g before passing out. Long and short of it, 8 m/s² sounds to me like relatively reasonable acceleration for a spacecraft. I was also thinking of the Fermi Paradox, which takes as part of its basis the assumed relative simplicity of alien civilizations colonizing or exploring space.
You're right, though, that the lack of consistant acceleration suggests a glitch of some sort. And I did read the Planetary Society article; it just seemed sort of vague to me on the specifics of the signal, and why it was being discounted. Why does the frequency drift suggest a natural source or a glitch? Also, why does the project assume that a real transmission would stay within a narrow band of frequencies? Lastly, does anyone know what the approximate range of the transmission from Earth was, in light-years? I haven't been able to find that information. But, in any case, thank you for your time. --Brasswatchman 21:34, 15 February 2006 (UTC)
Not to mention, 1g = 9.81 m/s² only applies when you're relatively close to the surface of Earth, an altitude which is fairly poor for an orbiting body. Actually, 8 m/s² for a body orbiting a star as massive as the sun is looking something like an orbit radius of m, about three times the radius of the Sun. But then, there are a lot of different sizes of star, so you can't really compare that much. Confusing Manifestation 10:51, 15 February 2006 (UTC)
I was primarily talking about the possibility of an artificial body transmitting this signal. One of the reasons the article says the signal was discounted was its relative distance from any known active stars. So a planetary transmission has already been discounted. Thank you for your time. --Brasswatchman 21:34, 15 February 2006 (UTC)
If it is something artificial, it seems like it would have to be fairly complex to explain the Doppler shifts. Out in the middle of nowhere, it should be tumbling rather than moving in some way that would require huge amounts of fuel. On the other hand, it could have had some kind of accident that's causing it to waste fuel uncontrollably. If it is using fuel, it will run out at some point and its signal should become very predictable or disappear forever. I'd think if it was out there transmitting for a specific purpose, we should be able to find similar sources in the same area, or at least one in the opposite direction.
It's also at least possible the Doppler shifts are themselves artificial. The object needn't move at all. Perhaps, for some reason, its targets are traveling in precisely predictable ways and it's more economic to put all the variable-frequency equipment in one place. ᓛᖁ♀ 02:37, 16 February 2006 (UTC)

Sail boat[edit]

I am in year five and i have to build a small boat which cannot be longer than 40cm, no wider than 30 cm and no taller than 80 cm. this boat must aslo be able to "sail" across a swimming pool. We can use a motor from a toy boat to use in my boat but i am still looking for more ideas on the motor and what materials and design i should use for my boat.

Please help. Thank you

I did this in school. I used a couple of balloons to power my boat. Drag is your biggest enemy. Is it who goes the fastest or who goes the furthest who wins? Theresa Knott | Taste the Korn 11:21, 15 February 2006 (UTC)
Oh dear, I didn't know women could be this competitive too. :) There's no reference to any competition in the question. Of course there will be probably be some grading involved (although even that isn't necessarily the case), in which case, if I were the teacher, I'd give good grades for a clever design (irrespective of what the other kids did - note I'm not from the US). But if you're ok with a fair grade you could go for the tried and tested method of a propeller attached to a rubber band, which you can wind up. That would require a sufficiently strong and rigid structure. The material doesn't have to be light. Boats can also be made of concrete. Just a matter of displacing enough water by having a hollow hull. So you could deliberately go for a heavy material and tell the teach you were inspired by Archimedes. Oh, and if the boat has to have a sail, without being powered by it (why? - that would be a really nice test), I suggest lowering it or making it very small to minimise drag. DirkvdM 14:24, 15 February 2006 (UTC)
It doesn't sound like it needs to have a sail. They only said it has to be able to "sail", meaning to travel over water by any propulsion method. While a heavier-than-water boat could work, on the small end you would want it to be as light at possible, to minimize the water displacement and thus the drag. It would also be a real pain if the boat sank, and making it entirely out of lighter than water materials will prevent that. Balsa wood would work, but if you're on a budget, perhaps popsickle sticks would be cheaper. Just don't use white glue, as it dissolves in water. Get a specific water-proof glue, like a silicone based one. I suggest a raft design, maybe covered with aluminum foil on the bottom to reduce drag. Any even easier design would be if you carve it out of a block of Styrofoam. I like the rubber band and propeller design, but be sure to test it first, as it might just go in a circle. StuRat 20:10, 15 February 2006 (UTC)
Well I am a teacher and i can tell you all kids are competative. Even if the teacher isn't looking for a winner - the rest of the class will be. Theresa Knott | Taste the Korn 17:59, 15 February 2006 (UTC)
I think all kids like to win, however, some aren't willing to risk being called a loser, so prefer to avoid competition altogether. StuRat 20:10, 15 February 2006 (UTC)
But I think that although some kinds aren't going to compete just because they may lose, most of them would compete. Just as Theresa knott said, if it isn't a race, the children will try to make it into one. --Bowlhover 22:44, 15 February 2006 (UTC)
While the rubber band idea will almost certainly work, if you're trying to get there in a hurry, and are prepared to spend money to achieve it, more conventional power sources can provide more power and thus speed. Electric motors are one possibility, but if you're looking for something really spectacular (warning: and potentially dangerous and polluting to the pool) model rockets could theoretically be adapted for the purpose. Talk to a) your parents and b) your teacher before even considering this kind of approach. --Robert Merkel 23:58, 15 February 2006 (UTC)
For a safer version of a rocket follow the water rocket link at the bottom. I've seen that idea at work on a few occasions and it can be (!) quite impressive. Or if you still want to use a spectacular 'real' rocket you could just take a ribbon of firecrackers cut the back ends off and mount that on the boat. I've done this with single firecrackers and if you're carefull it's a probably a lot safer than letting the firecracker explode (normal usage). The ribbon will let them go off in succession, giving a longer sustained propulsion. Still, indeed, check with the teacher first if this is ok. DirkvdM 10:12, 16 February 2006 (UTC)
The trouble with most water rockets are that they have an enormous amount of power initially then nothing once all the water has gone. Plus they are heavy. That's why I asked is it the fastest or the furthest? If you only have a short way to go then a water rocket may well work. If you are trying to go a long way then you want a power source that can keep on going for as long as possible. I very much doubt that any teacher would allow firecrakers, but you never know.
Also bear in mind that the more complicated the design the more likelyhood of something going wrong, KISS (Keep it simple stupid) Theresa Knott | Taste the Korn 10:52, 16 February 2006 (UTC)
I suggest a large aluminum tube which has been made out to resemble a Submarine. Fitted with deep-cycle batteries running an electric motor.
I would use a "candle powered jet boat" (see Relatively easy to make, powerful and long running. The hardest bit will be steering the boat to make it go starightacross the pool. (PS I couldn't find this as a wikipedia article - should it be one? I'm not offering to write it. -- SGBailey 23:45, 18 February 2006 (UTC)

Is $100 laptop a scam?[edit]

Is the $100 laptop a scam?

I think when the laptop as it is called finally arrives, will be nothing more than a PDA with a slightly larger screen. Yes, only a slightly larger screen.

Or should we say it as a enhanced ebook reader in the shape of laptop?

Which 100$ laptop? Are you thinking of a specific one? Is it second hand? Sold by an individual or a shop? Can't you see it (and why then)? And are those Kiwi, Aussie or Signapore dollars? DirkvdM 14:29, 15 February 2006 (UTC)
It's good to read a little before making bold statements $100 laptop --Zeizmic 16:05, 15 February 2006 (UTC)
Ah, it's a specific term. I hadn't heard of that name, although I know of the project. A bit confusing, referring to the price in stead of the principle (which is....?), especially since it uses a specific currency (although there are several dollars in the world - extra confusing). Also, when the price drops (as LCD screens get cheaper) the name will no longer be accurate. How about '3rd world computer' or 'wind-up computer'? Or OLPC? That would make clear it's about something specific. Or 'green machine', although is again a more general term that could mean loads of things. DirkvdM 10:34, 16 February 2006 (UTC)
That would be severly stretching the definition of a "scam". The only problem with the $100 laptops is that no company wants to make them since they won't generate any profit. If they're only making a couple of bucks profit on each laptop, then it would be extremely difficult to recoup their losses. I think you're misunderstanding the point: the laptops were designed so that children in developing countries who could never otherwise have a computer will get something for extremely cheap with some functionality, access to the web and ability to work without electrical outlets. The purpose isn't for IBM or anyone to make money in countries like the US. — Asbestos | Talk (RFC) 16:50, 15 February 2006 (UTC)
Of course, if it's not going to be profitable, you're going to have trouble convincing anybody to make them. Also note that the $100 full function laptop will be available, and profitable, some day, it's just a question of when. However, even at $100, many in developing countries still couldn't afford them. StuRat 19:41, 15 February 2006 (UTC)
you realize it's about as much of a computer as your average graphing calculator, and half a functional, at twice the cost, of course they could still make a profit-- 23:22, 15 February 2006 (UTC)
I read an interview with a Nigerian politician recently and his opinion was: 1) They don't have a dire need for computers. 2) The money spent on these computers would be better spent on medication and schooling. 3) The charity organizations that have pledged to purchase thousands of these computers are wasting their money. 4) The people behind the computers are doing it just to get rich off the charity organizations that will buy the computers. --Kainaw (talk) 21:26, 15 February 2006 (UTC)
Stating an argument more than once doesn't make it more true. That's all just one argument - the money would be better spent in a different way. Except for the fourth argument, but then I don't see what's principally wrong with that. DirkvdM 10:34, 16 February 2006 (UTC)
It would all depend on how poor the country is. In a society so poor they can't afford pencils and paper, buying a computer for every student is a bit silly, they should spend the money on the basics first. In a slightly better off country, like China, perhaps the computers could be put to good use. StuRat 22:21, 15 February 2006 (UTC)
I don't think its exactly a scam but iirc it relies on essentially getting parts at far below thier normal market value and/or highly comprimising the machine until (as the op stated) its little more than a PDA. Plugwash 16:56, 15 February 2006 (UTC)


Does tincture iodine help to stop bleeding?If so,how?

thank you 14:09, 15 February 2006 (UTC)emili59.92.45.242 14:09, 15 February 2006 (UTC)

it does not. It is, however, a fairly effective antiseptic. —Charles P._(Mirv) 18:27, 15 February 2006 (UTC)

ISO/IEC 15288[edit]

Dear reader,

I'm trying to locate and collect more information about the following subjects: - ISO/IEC 15288 standard, System Life Cycle Processes

- Service Aarchitecture Organisation (SOA). I've seen quite some information which is presented by companies that try to sell their solution / implementation. However that is colored information. I'm trying to collect objective information (shortfalls, problem encountered with the implementation, access control, authentication / authorization, etc) on this subject SOA.

Thanks for your cooperation.


Wim Hanssen

Phone: 0049-2451-63-3036 (work)

How much HD space does Wikipedia's servers have?[edit]

No one answered on the Village Pump's technical section, so I had to ask here.

  • How much HD space do ALL of Wikipedia's servers have in total?
  • How much HD space has the English Wikipedia consumed so far?
  • How much HD space has all of the Wikipedias consumed so far?

--Shultz 18:55, 15 February 2006 (UTC)

Thats a tricky question... are you counting all copies of the standard Wikipedia? Much of the space is dedicated to holding duplicates of the articles so that servers can act in parallel. Perhaps this tidbit on hardware is a good place to start?

Wikipedia:Reference_desk_archive/Miscellaneous/January_2006#How_much_hard_disk_space_does_Wikipedia_use. Basically it's a trivial amount. Markyour words 19:08, 15 February 2006 (UTC)
From both the answers there and the size of the image dumps at, I wouldn't say it's a trivial amount. --cesarb 20:11, 15 February 2006 (UTC)
From what I've heard the history is the kicker. There's thousands of times more space needed to store the history of Wiki than each page's current revision. I had a source, I'll try to find it again, that quoted the Wikipedia's servers having a hard-disk capacity third in the world, behind google and the Internet archive.  freshgavinG???  00:35, 16 February 2006 (UTC)
Well I would really doubt that but we do have a fair amount. The question appeared to be asking how much space do the servers have, everyone else was trying to answer how much space does the information take up. For the first question you could actually just go to m:Wikimedia_servers and add up the capacity listed. A quick off the cuff estimate would say most of the 171 servers have more than 80GB of HD space in them, for almost 14TB, but it's probably a bit more since some of them have 200-400GB or more. Now we don't own all those, some are just donated hosting service like the Yahoo servers. And no we don't use anywhere near all that space, but since it's not cheaper to buy a new server with a drive smaller than 80GB, they just get them anyway. If you feel like crunching the numbers let us know what you come up with. - Taxman Talk 20:40, 16 February 2006 (UTC)
Having set up my own local copy of the English Wikipedia, the space used by the current versions of all pages, but without images or "what links here" tables, is around 8.3 GB. Based on the expansion factors and the size of the compressed "all versions" download, a full mirror of the English Wikipedia, not including images will check in at around 120-130 GB. Images add another 76 GB or so. --Carnildo 19:24, 20 February 2006 (UTC)

Cane toads[edit]

What ingredient in hemorrhoid cream explains why the RSPCA would recommend spreading it on Australian cane toads? [6] ᓛᖁ♀ 19:42, 15 February 2006 (UTC)

Benzocaine (the ingredient in question) is an anaesthetic. It numbs the toad. Then, it can be frozen or boiled for a humane death. The issue is that people are worried that clubbing the toads causes an inhumane slow and painful death. I would like to say this is a joke, but everything I've seen shows it is a real issue. --Kainaw (talk) 21:39, 15 February 2006 (UTC)
Interesting idea. I'm not entirely sure that if I were to apply hemorrhoid cream all over that I wouldn't find boiling painful and freezing unpleasant. What about my eyes? The cream would sting if I put it in my eyes, but boiling my unprotected eyes doesn't sound cruelty free. Clubbing would hurt too, but at least sounds quicker. And decapitation sounds quicker still. Notinasnaid 23:49, 15 February 2006 (UTC)

Histones 1-2A-2B-3-4[edit]

Hallo! I am searching webpages wich gives the entire sequences of amino acids in these histones (for some representative species). Could you possibly help me find such links - if there are any? I have only found a couple of "fragments" out of global domains of the H1-histone. (Perhaps something to add to your pages about histones?) With kind regards

Åsa 19:51, 15 February 2006 (UTC)

Searching the NCBI protein database for "histone" gives over 24000 protein sequences. I don't think adding protein sequences to Wikipedia is really within its scope: it's an encyclopedia, not a biosequence database. Chuck 15:22, 16 February 2006 (UTC)

(No title given)[edit]

For an ideal gas with constant specific heats, derive the relationship between pressure and density for an isentropic process, beginning from the TdS equation(s).

Do your own homework: if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers. Letting someone else do your homework makes you learn nothing in the process, nor does it allow us Wikipedians to fulfill our mission of ensuring that every person on Earth, such as you, has access to the total sum of human knowledge. —Keenan Pepper 05:57, 17 February 2006 (UTC)

Anthropology Question[edit]

1)What kind of saw cuts best through human bones?

2)Where on the internet can I find plans for a small bomb that can kill 10-20 people?

3)Where is the best place to dispose of human bodies so that the police won't find them?

Thanks --ericder

The preceding unsigned comment was added by (talk • contribs) 23:27, February 15, 2006 (UTC).

1) A bone saw, of course.
2) Read pipe bomb.
3) The bottom of the ocean.
4) Let us know when you are accessing Wikipedia from prison so we can laugh at you.
--Kainaw (talk) 00:00, 16 February 2006 (UTC)
This leaves us with the question, what does this have to do with anthropology? and does this make Kainaw an accomplice? ᓛᖁ♀ 01:28, 16 February 2006 (UTC)
Helping out a terrorist? Oh yes, it's straight to Guantanamo Bay for Kainaw. Which would give us an insider for that article (let's not forget the bright side of things). Just two problems (no reason for blind optimism): 1) It would be original research 2) How does he get the info out? I don't suppose the prisoners get internet-access. DirkvdM 10:42, 16 February 2006 (UTC)
  1. A circular saw would be quite handy.
  2. Various home-made explosive sites exist on the internet, including Megalomania and The Big Book of Mischief.
  3. I'd say a better idea to dispose of the bodies would be a nice big barrel of sulfuric acid, as per the Acid bath killer, and then dump the remains into the ocean. Just make sure to remove any dentures first. GeeJo (t) (c)  10:59, 16 February 2006 (UTC)

question about bitTorrent[edit]

Does anyone else keep getting DivX files that are badly screwed up, and crash every 2 or 3 minutes into a giant green blur then fail completly? is it that people are idiots and don't know how to encode DivX files correctly? or is some kind of "copy of a copy of a copy" scenario somehow related to the way multiple sources are stitched together into one file? Or something else complety? also, anyone know a way to fix it? or avoid it?--DivOX 23:33, 15 February 2006 (UTC)

The way BitTorrent works, the copy is completely identical to the original, so it's not a "copy of a copy" scenario. You probably have a broken codec installed. --cesarb 23:40, 15 February 2006 (UTC)
Well, actually, no I don't, the only files that don't work are from BT, and they always die at the same spots, whatever the cause the compression fails at certian points, and the file dies, non-BT files encoded with divX work just fine, so..--DivOX 23:56, 15 February 2006 (UTC)
Which BT client are you using? Did you try with another client (for instance, the official one)? Did you check the CRC of the file (some people put it in the filename), or run a md5 or sha1 on the file and compare with someone else who has the same file? --cesarb 00:18, 16 February 2006 (UTC)
I hear that copyright holders have been "polluting" various P2P pools with deliberately broken files. I don't know if bitTorrent has been affected, but that might be what you're up against. Steve Summit (talk) 00:24, 16 February 2006 (UTC)
  • Ok, new approach: BT will ocassionally terminate files at about 98 to 99% True; These files will be playable but degraded True; BT will occasionally declare these files "complete enough" True, so why isn't it possible that if someone were to seed a file that's been capped off at 98% could have some sort of glitch? or seam if you will? especially if there was more than one source? both slightly different? Wouldn't this also explain why older files that have been passed around more tend to be more degraded than more recent files?--DivOX 00:11, 16 February 2006 (UTC)
  • also, yes I know what a codec is, very funny--DivOX 00:11, 16 February 2006 (UTC)
If you are using the original torrent file, even if someone tries to seed with an incomplete file, BT will detect it and seed only the completed pieces. They are also checked on download, so even if someone is sending corrupted pieces, they will be rejected. It is possible that the creator of the torrent file had a corrupted file; if that's the case, you should get your torrent files from more reliable places. BitTorrent will never say the file has completed downloading before it really has completed downloading (100% downloaded), so that's not the issue. --cesarb 00:18, 16 February 2006 (UTC)
And though I know you have claimed to know what a codec is, you might also just check that they are all up to date or just try reinstalling them, i.e. by downloading the latest DefilerPak or whatever codec pack you prefer. I find codecs to be mercilessly annoying and often the source of things like this, and I say this even as someone who is pretty computer savvy. --Fastfission 23:08, 16 February 2006 (UTC)

February 16[edit]

Vitamin C Crystals[edit]

I would like to know the source of the bulk vitamin C crystals one buys in health food stores please. --Marvern 00:16, 16 February 2006 (UTC)Marvern

Those are almost certainly synthetic ascorbic acid. --James S. 00:59, 16 February 2006 (UTC)
Especially if they don't list some drivel on the package about how they are harvested from Tahitian noni berries or some such thing. Silence = chemicals from some labratory. StuRat 05:01, 16 February 2006 (UTC)
I wouldn't say that. Organic synthesis can be quite expensive. It's a case-to-case thing. And in some cases, people would perhaps prefer it was synthetic; hyaluronic acid is usually produced from rooster combs. --BluePlatypus 16:32, 16 February 2006 (UTC)
People who buy nutritional supplements have a very strong preference for "natural" and "organic" sources, so the manufacturer would be sure to put such labels on the bottle if they could. StuRat 08:12, 17 February 2006 (UTC)

From the Vitamin C article. - Artificial L-enantiomer Vitamin C ( is produced from glucose by two main routes. The Reichstein process developed in the 1930s uses a single pre-fermentation followed by a purely chemical route. The more modern Two-Step fermentation process was originally developed in China in the 1960s, uses additional fermentation to replace part of the later chemical stages. Both processes yield approximately 60% vitamin C from the glucose feed.

In 1934, the Swiss pharmaceutical company Hoffmann-La Roche was the first to mass produce synthetic vitamin C, under the brand name of Redoxon. Main producers today are BASF/Takeda, Roche, Merck and the China Pharmaceutical Group Ltd. of the People's Republic of China. China is slowly becoming the major world supplier as its prices undercut those of the US and European manufacturers. It is chemically identical to that produced in living things.[7]. Lumos3 08:32, 22 February 2006 (UTC)

Who discovered calcium and magnesium are essential nutrients?[edit]

Nutrition is the Wikipedia:Science collaboration of the week, and I've been doing the history section. I've got all the history of the vitamins and essential amino acids and most of the misc. details, but the Dietary minerals are driving me up the wall -- I've been googling for half an hour and I still don't know when calcium was recognized as an essential nutrient and by whom. I've decided that all I want to add is calcium and magnesium, because finding historical info on other minerals is too hard. --James S. 00:59, 16 February 2006 (UTC)

The three criteria of an essential nutrient are that it be found in all healthy individuals, that complete elimination of it from the diet leads to harm, and that it cannot be synthesized from other substances in the body. No animal can transmute elements like Ca and Mg, so if we need to have it in our bodies it is an "essential nutrient". They have been known to be part of animal and human bones and bodies for at least 2 centuries, but it may be hard to identify who first found them in animals. alteripse 19:07, 16 February 2006 (UTC)

I have found the answer and will be merging more historical information into Nutrition today or tomorrow. --James S. 20:35, 21 February 2006 (UTC)

Mollies and Swordtails[edit]

I'm doing a science project on hybridizing livebearing fish and I was wondering if it is at all posible that Mollies and Swordtails will hybrid?

Please contact me at Saving your inbox from flooding

They never have before in normal tanks. --Zeizmic 02:44, 16 February 2006 (UTC)


Is Gatorade really that much more effective at hydrating people than regular water? Isn't it just water with sugar, salt, and food coloring? --JianLi 05:43, 16 February 2006 (UTC)

It's important for athletes to replace the salts that are lost by sweating, so yes, it is better than water. David Sneek 08:09, 16 February 2006 (UTC)
It is more important for athletes that have been working hard for over ~25 minutes, that need rehydration. It rehydrates better because of the electrolytes in it that help fluid balance within the body's cells, and the extra sodium in it aids absorption. -- Flag of the United States.svg Mac Davis ? ญƛ. 09:41, 16 February 2006 (UTC)
Don't know from Gatorade, but it sounds like plain old ORS (a stub alas). Well, a bit more than that. ORS uses an isotonic solution to make sure the water gets absorbed faster. When used for sports in stead of diarrhoea you'll also need the salts (as said) and sugar (for energy). But those are also present in, say, Orisel - handy sachets for travelling (which is what I have them for), one for 300 ml. You just need to add the water (so it's much easier to carry around). But that has to be precisely measured. Especiially a hypertonic solution (too little water) would only make things worse (rather like drinking sea water). The Gatorade aritcle says it contains "127 mg/l of potassium and 464 mg/l of sodium, and 59 g/l of carbohydrates (in the form of sugars)". That's a total of 60 g/l, almost only sugar (so it's basically sugar water - you might as well drink Coke). An Orisel sachet has 8,4 g for 300 ml, so that's less than 30 g/l. Which makes me wonder if Gatorade isn't hypertonic. What causes the discrepancy? Maybe Orisel stays on the safe side in case people make mistakes? The isotonic article even says an isotonic solution is only 9 g/l. So why can these solutions have such a high osmotic value? DirkvdM 11:02, 16 February 2006 (UTC)

I think you may be confusing mg with mosm or mEq. Osmolality is determined by moles, not by wt. Isotonic fluids have about 300 mosm/kg, typically about 140-150 mEq/L of Na. Glucose is heavy but there is only 1 mosm per 18 mg. Gatorade is hypotonic, not hypertonic. alteripse 18:37, 16 February 2006 (UTC)

OK, here are details of Gatorade composition per L: 20 meq Na, 3 meq K, 50 g glu. In terms of salt content, this is very hypotonic. The site claims an osmolality of 330 mosm/L, which is nearly all derived from the 50g of glucose. However, this is gut osmolality, and most of the glucose will not be available to contribute to ECF osmolality as the Gatorade is digested and absorbed. alteripse 19:00, 16 February 2006 (UTC)

I suspect that more sugar (and possibly sodium) is added to Gatorade than is ideal, since more sugar makes a product taste and sell better. StuRat 22:14, 16 February 2006 (UTC)
Very plausible, because Orisel tastes rather salty (though not unpleasantly so, I find). That's also a commercial product, but it has a specific medical purpose, so people will easily accept the taste. So if you want to rehydrate and keep your salts up to scratch drink an ORS solution. If you like lemonade, drink Gatorade. DirkvdM 08:33, 17 February 2006 (UTC)


This question may sound silly but still its a doubt. Iron, calcium etc are essential nutriens for our body. So can we eat raw iron etc? why?

Yes, you can eat raw iron (like iron filings). Most of it would pass through you undigested but you dont need much and I suspect you might digest enough to meet your iron needs. Trace elements need to be in a digestible or absorbable chemical state, and usually in a palatable state as well. Few trace elements (except some of the metals) exist in a pure state. alteripse 12:08, 16 February 2006 (UTC)

It's quite tricky to absorb these nutrients with any supplements. For example, calcium and magnesium are useless without Vitamin D. I find that the only way to absorb iron is by using ferrous gluconate with a Vitamin C pill. --Zeizmic 12:25, 16 February 2006 (UTC)
It is not absolutely necessary to take ferrous gluconate with vitamin C. - Cybergoth 22:31, 16 February 2006 (UTC)
Calcium and magnesium are not "useless without Vitamin D" -- most people don't get as much of either mineral as they need, but most people who are outdoors for an hour or two a day generate sufficient vitamin D to fully metabolize the proper amount of calcium and magnesium. Sadly, a lot of the popular wisdom concerning nutrition is inaccurate advertising from supplement manufacturers. --James S. 17:17, 17 February 2006 (UTC)
Some breakfast cereals actually contain metallic iron filings. They're called "reduced iron" in the ingredients. If you crush the cereal you can use a magnet to collect the iron. —Keenan Pepper 18:52, 17 February 2006 (UTC)
Not absolutely necessary ? You can use a magnet ? No personal research please. Cite your sources. --DLL 21:57, 17 February 2006 (UTC)
This isn't a Wikipedia article. You ask a question, we try to answer it. You can debate it. Take it or leave it, but I'm not going to look up primary sources. (See human iron metabolism - Cybergoth 01:43, 18 February 2006 (UTC)
I forgot the smiley. --DLL 20:43, 18 February 2006 (UTC)


Almost both sexes of all animals have the same number of chromosomes. Then why is it different for cockroches

That's an interesting–and excellent!–question. There are actually a number of different genetic sex-determination systems that crop up in organisms; there's a description of them in that article, but unfortunately it doesn't (yet) address cockroaches.
Human sex is determined by the familiar XY system. Women have two X chromosomes (XX) and men have one of each (XY). There's no particular reason why we couldn't have evolved differently. Birds and some insects have the so-called WZ selection system, where males have two Z chromosomes (ZZ) and females have the unmatched pair (WZ).
Some other insects, including those from the orders Orthoptera (grasshoppers, crickets, and others) and Blattodea (cockroaches) have what is often called XO selection. Females have two X chromosomes (XX), whereas males have only one (XO, where the O denotes the absence of the chromosome). Our current understanding is that it is a sort of dose-response effect&nmdash;getting hit with two 'female' chromosomes is enough to trigger the mechanisms that turn the organism into a female.
There are variations on the the theme, too. In the nematode Caenorhabditis elegans, XO animals are male, whereas XX animals are hermaphrodites.
It's also possible to have an XO human. Occasionally, the Y chromosome will be lost or damaged, resulting in a fertilized embryo with a single functional X chromosome. While most such embryos will spontaneously abort, occasionally one will grow to full term. An XO human will always be female; the genetic condition is called Turner syndrome and is associated with an increased predisposition towards certain health problems. TenOfAllTrades(talk) 15:34, 16 February 2006 (UTC)
  • Hey, the platypus has 10 sex chromosomes. Obivously it's 5x better than people then. --BluePlatypus 16:17, 16 February 2006 (UTC)

Doesnt any one have an answer for my Question?

I thought TenOfAllrades answered it. Female cockroaches have an even number of chromosomes and males a uneven number. Or wasn't that the point he made? DirkvdM 17:56, 17 February 2006 (UTC)
It does seem odd that so many different methods seem to have evolved to do the same thing. Can anyone explain the relative advantages of each method ? StuRat 08:08, 17 February 2006 (UTC)
The question was why. RD people love to say how and what and how many.
Sexes in cockroaches have a different number of chromosomes Because There is an Intellignet Desgin, that's why. --DLL 21:53, 17 February 2006 (UTC)
With a designer who can't count. DirkvdM 09:32, 18 February 2006 (UTC)
Saying it's intelligent design is just a cop-out. There is no particular reason to think that a god would want to create a different gender determination mechanism for different species, so it just amounts to "I don't know why it's that way, let's just say God did it and we have no idea why God does anything". By this argument there is no point in asking why anything is the way it is, so let's just close down all scientific study and say "because God wants it that way" whenever any question is asked. StuRat 21:26, 18 February 2006 (UTC)

work at Google[edit]

Do employees of Google play & have fun all day and never work at Google?

Um, no. They play, have a lot of fun, and do a lot of hard work for Google. --Ashenai 13:07, 16 February 2006 (UTC)
See Google, googleplex, and try not to be too swayed by the lava lamps and excercise balls.  freshgavinG???  06:14, 17 February 2006 (UTC)

"mullet" finger[edit]

My little finger pulls back toward my wrist and it has been called a "mullet or Mulett finger. What is this condition?

DNA testing and Cotton swabs[edit]

We always see DNA samples taken by swabbing a person's cheek with a cotton-swab device-- a sort of elongated q-tip. The DNA collected can then be used for testing. My question is: why doesn't the DNA from the cotton plant contaminate the sample? Is the cotton-like fiber some synthetic that never came from a living creature? Is the fiber really devoid of cotton dna, just as human hair lacks DNA? Does some sterilization or cleaning process remove cotton-cells from the fiber? Or is plant DNA just so dramatically different from human that it's easy to screen out in the testing process? Or something else I haven't considered? -Alecmconroy 14:24, 16 February 2006 (UTC)

  • Some swabs are made from entirely synthetic materials like Dacron (polyester). (Cotton's cheaper, though.)
  • Cotton fibers, like hair or fingernails, contain no DNA—they're a nonliving product cranked out by the cotton plant.
  • Swabs for analytical use are typically sterilized using gamma irradiation. This kills of any nasty things that you wouldn't want to swab someone's mouth with, and also tends to shred any DNA that might be present.
  • Forensic DNA testing typically looks for a set of markers that are unique to human DNA; al small amount of plant DNA shouldn't present a problem.
Congratulations on your excellent guesswork. :D TenOfAllTrades(talk) 15:48, 16 February 2006 (UTC)


I just went to an ophthalmologist and he said I have little dots on my eyes, because of dryness, called SPK. He said what it stood for, but I don't remember. I wanted to do some reading about it, but I didn't see anything right off the bat for SPK. If anyone knows what it stands for it would help a lot. Thanks!! --Dimblethum 17:24, 16 February 2006 (UTC)

I found it. It is superficial punctate keratitis. --Dimblethum 19:24, 16 February 2006 (UTC)
There's an article here, Thygeson's superficial punctate keratopathy, in case you haven't seen it yet. --Trovatore 19:30, 16 February 2006 (UTC)

AIDS naming[edit]

why is aids not called a disease but a syndrome

Because when it first appeared it was not known how the different symptoms of aids (the "syndrome") were connected. See Syndrome. David Sneek 20:01, 16 February 2006 (UTC)
Plus, HIV is usually considered the actual disease, and AIDS is generally the symptoms of HIV manifesting. smurrayinchester(User), (Talk) 09:07, 20 February 2006 (UTC)

toxicity of nicotine[edit]

I need help for research on the toxicity of nicotine

Here is the official Material Safetly Sheet. that would seem like a good place to start. David D. (Talk) 18:02, 16 February 2006 (UTC)

One interesting fact: nicotine is so toxic that farm workers must wear gloves. That's because evaporating dew or raindrops on the leaves can concentrate nicotine to such an extent that the amount absorbed through the skin can cause a heart attack. StuRat 22:04, 16 February 2006 (UTC)
And then they gotta find more farmers!  freshgavinG???  06:11, 17 February 2006 (UTC)
  • And then, it's all sent to cigarette manufacturers... and people who smoke (without gloves). - Mgm|(talk) 09:45, 17 February 2006 (UTC)


How does Bacteria doble? Aidan age:8

Check out this wikipedia page: Binary_fission. David D. (Talk) 18:04, 16 February 2006 (UTC)

Here is an answer more suitable for an 8 year old:
  • First, a small bacterium absorbs food all around it.
  • Then it gets fat.
  • Then it splits into two smaller bacteria. This is called mitosis.
  • Then each of the two small bacteria absorb food, get fat, then split into two each (for a total of four).
  • They keep on doing this, doubling with each new generation, until they run out of food or something kills them.

StuRat 21:53, 16 February 2006 (UTC)

Right, StuRat, except it's not called mitosis; it's called binary fission (which basically means "splitting in two", Aidan). Bacteria do not undergo mitosis. — Knowledge Seeker 01:06, 17 February 2006 (UTC)
OK, I see now that mitosis refers to a cell with a nucleus and binary fission to a cell without a nucleus, but both processes result in one cell ending up divided into two identical daughter cells. I think the difference is pretty minor, especially as far as an 8 year old is concerned. StuRat 01:44, 17 February 2006 (UTC)
It's still important to be informed of the difference, though, just as it's important to know that the speed of light in vacuum is not exactly 300 000 km/s. Also, when we normally talk about getting fat, we talk about gaining adipose tissue. Bacteria don't have adipose tissue, so let's just say they grow. --Bowlhover 03:46, 17 February 2006 (UTC)
I believe he was trying to personify the bacteria, to make the explanation enjoyable!  freshgavinG???  06:08, 17 February 2006 (UTC)
Yes, and make it accessible to an 8 year old. Also, growth doesn't imply "exceeding the ideal size for the organism" as the phrase "getting fat" does. StuRat 08:01, 17 February 2006 (UTC)
And I do believe you've exceeded the size of your organism!  freshgavinG???  14:41, 17 February 2006 (UTC)
Hey, there's an 8 year old reading this! Go wash your organ with soap. And very cold water. Anyway, StuRat said ideal size and what that is is open to a lot of discussion. DirkvdM 18:08, 17 February 2006 (UTC)


Are there any evolutionary biologists that have theories about why humans developed the ability to cry? Does it have something to do with triggering feelings of empathy in others? -Quasipalm 21:17, 16 February 2006 (UTC)

Here's one for baby screaming, if that's what you mean. [8]--Zeizmic 21:42, 16 February 2006 (UTC)

The original purpose was definitely to wash irritants from the eyes. How this became used as a method of conveying one's current emotional state to others is a bit of a mystery to me, however. StuRat 21:48, 16 February 2006 (UTC)

Now I just scanned for emotional tears and evolution. There is a general consensus that crying must be rewarding (against sadness), and some talk about male/female comparisons. In general, it seems very iffy to me. --Zeizmic 22:58, 16 February 2006 (UTC)

What's more than a bit of a mystery to me is how a baby's parent or carer can just let the baby cry and cry and cry before finally getting around to responding to their needs. To me and a lot of people I know, a baby's crying is distressing, which suggests it is the baby's way of getting the parent's attention. They don't have language skills yet, so this is how they get to survive. The baby does not have the ability to recognise that some feeling they're having is not a life-threatening emergency but a temporary minor discomfort. The theory that "if you give into a baby's every cry, you'll only spoil it" is, in my opinion, one of the most misguided philosophies so-called civilisation has ever dreamt up. (That's it for my rant for today). JackofOz 05:43, 17 February 2006 (UTC)

I'm guessing you haven't had a baby to care for. After you are seriously sleep deprived from their incessant crying, you might change your attitude a bit. StuRat 07:57, 17 February 2006 (UTC)
Sorry, StuRat, but I have very personal experience of sleep deprivation. My sons are 28 and 21 (almost, it's his birthday tomorrow), so it has admittedly been some time, but my memories of years (literally) of No.2's night terrors is still very vivid. Study of transpersonal psychology has given me some insights into stages of consciousness. Most parents don't have that knowledge; but all parents are humans and they have to "switch off" in order not to be affected by a baby's cry. Some people are better at switching off than others; but for those who can, the question is "whose needs are being served by me switching off?". It's usually the parent's needs. Fair enough, parents need time out, but the time for that is not while they're doing the shopping at the supermarket and the kid is crying incessantly, getting no response from the parent, and causing distress to dozens and perhaps hundreds of people. As bad as that is, it's nowhere near as bad as the kid's inner state of turmoil and terror. But somehow it's not PC for anybody else to say or do anything about this. I've just mixed up a few ideas, but the common thread is that the very best thing a parent can do for a child is to let them know from Day 1 that their needs will always be met, and that they will always be loved unconditionally. That will instill such a core belief system into them, and they will find that, surprise surprise, life tends to turn out that way for them. So far from spoiling the child, this will in fact liberate the child and enable them to achieve more of their potential. (Thus endeth today's lesson. Go in peace.) JackofOz 08:52, 17 February 2006 (UTC)
I agree that babies should not be allowed to cry in those places, but think keeping children home until they are old enough to behave in public is the answer. For those parents who ignore this rule, surely they wouldn't object if someone goes out in public who is similarly unable to control themselves ? So, I just pretend I have Turret's Syndrome and swear at them constantly, until they leave and take their brats with them, LOL. StuRat 18:15, 17 February 2006 (UTC)
That's Tourette syndrome.  :) JackofOz 22:46, 17 February 2006 (UTC)
If everyone thought logically about their actions as they were doing them, the world would be a much, much better place than it is now.  freshgavinG???  06:00, 17 February 2006 (UTC)
Yes, but as Anatole France put it: It is human nature to think wisely and act in an absurd fashion. JackofOz 07:53, 17 February 2006 (UTC)
I like to think it's more along the lines of It is human nature to listen to people using big words, think about the stuff they say for a minute and then say "I don't get it, must be right!" and then go back to creating stupid babies.. But then again, I'm one of those people acting in absurd fashions.  freshgavinG???  14:39, 17 February 2006 (UTC)
Me too. JackofOz 22:46, 17 February 2006 (UTC)

are DVDs going comleatly[edit]

I just read about them doing blu ray movies and other types of new kinds of dvds does this mean that they are going to stop makig things as DVD because i realy wouldn't like that i speant years building up the ultimate colection

The new formats are coming but the players that play the new DVDs should also play older DVDs. So your collection should still be playable. The disc size is the same. Dismas|(talk) 22:29, 16 February 2006 (UTC)
That said, it's probably just a matter of time before DVDs are replaced with some entirely different format, say one that supports full virtual reality movies. Then DVDs will go the way of 8-tracks, record albums, and cassette tapes (on their way out now). StuRat 01:24, 17 February 2006 (UTC)
  • I don't know about you, but I still use video casettes, and I doubt DVDs will phase out before the majority of the world population has started to use Bluray (or before video cassettes are no longer used). Otherwise, they're going to lose a lot of customers. - Mgm|(talk) 09:50, 17 February 2006 (UTC)
DVDs will go as soon as possible, if the people in chart of the entertainment business can only find a convincing replacement. They just love having the opportunity to sell us our existing favourites all over again, and to sell for a while a premium product at a premium price. Of course not all attempts at medium upgrades have succeeded in the marketplace. Notinasnaid 11:03, 17 February 2006 (UTC)

What are the functions of the nose?[edit]

Yeah, I can go back to being rude, and telling people to type 'upyournose' in the magic answer box at the left. (That's a joke, to all you 'easily offended' types. I don't want my embassy stormed.) --Zeizmic 00:00, 17 February 2006 (UTC)
Too late, the imam has called for a jihad against you, your country, your continent, your race, and pretty much everyone on Earth except the imam who issued it, by now. StuRat 01:11, 17 February 2006 (UTC)
I think your comment is going to offend a lot more people, StuRat. As for the question. Try Nose. - Mgm|(talk) 09:53, 17 February 2006 (UTC)
I disagree. Imams have been known to chuckle. Hell while we're all wasting our time typing here we might as well answer his question and direct him to smell.  freshgavinG???  14:32, 17 February 2006 (UTC)

Noses are used for breathing, smelling, as a resonance cavity for speech, and, of course, to hold your glasses up. Nose hairs and snot are used to try to filter out many of the nasties you would otherwise inhale thru the nose. StuRat 17:57, 17 February 2006 (UTC)

Noses can also be used for bleeding, counting (or, rather, being counted), pointing in a direction (the same one as all the other noses, except for mine), sticking into things (preferably other people's affairs), following, looking down, turning up, paying through, hitting against the legs of chairs and such (in the case of shoes) and consequently diving. Noses are, however, not used for breathing. The lungs do that. Noses are just considerate enough to have two holes in them so they don't get in the way. DirkvdM 18:28, 17 February 2006 (UTC)

I can play simple songs on the piano with my nose.  freshgavinG???  18:40, 17 February 2006 (UTC)

Maybe if you start now, you can learn to play Shostakovich's opera The Nose, in time for his 100th birthday celebrations on 25 September 2006. JackofOz 03:20, 18 February 2006 (UTC)
Is there also a version for the left nose? DirkvdM 09:33, 18 February 2006 (UTC)
Not that I've heard. I'll do a bit of sniffing around to see if I can find one. :-) JackofOz 23:48, 18 February 2006 (UTC)

February 17[edit]

sources of error in satellite image rectification[edit]

hi, i would like a list of the sources of error in theory and practice in satellite image rectification using image-to-image and image to ground control points approaches. thanks

Miniature Golf- Obstacle at an Angle[edit]

I originally asked this question in Mathematics, but can a scientist/physicist help me??? Plaese and Thank you!!!

I have to design a hole-in-one using a bank shot at several angles. I know that angle of incidence = angle of reflection, but is that true when the obstacle is at an angle besides 90 degrees to the horizontal, such as 60, 45,30, 50,etc. Here's a simple diagram:

                                                \   ( Angle of Reflection) 
                                                    \                                   /
                                                       \                             /   (Obstacle- 45 degrees to parallel wall)
                                                          \                      /
                                                            \                /
                                                              \          /
                                                                \    /

/----------------------------------------------------(Imaginary Horizontal Parallel to Wall)


(Angle of Incidence) /


Thank you for your help! Please answer if possible as soon as possible?! Go Wikipedia!!!!!!! You may have to use physics, geometry,etc. For the purposes of a middle/ high school project for now I'm assuming under my teacher's directions that there isn't friction and no energy is lost. Signed, Sarepr91

Math was the right place, and we already answered it there, please don't double post. StuRat 01:01, 17 February 2006 (UTC)

Waxed fruit[edit]

Does anyone know anything about the wax-like substance that fruit is often coated with in grocery stores? --Smack (talk) 03:59, 17 February 2006 (UTC)

From a Google search for the terms "wax-like fruits" (the quotes are not included), I found these two webpages:
Hope that helps. --Bowlhover 04:46, 17 February 2006 (UTC)
From this site, the most common coatings are carnauba wax and shellac ('lac wax'), though there are some others. TenOfAllTrades(talk) 05:25, 17 February 2006 (UTC)
That would kind of cause problems for vegetarians, wouldn't it? I would have thought that stores would make it known what they are coating their fruit (and other produce) with so that consumers could make an informed choice! User:Zoe|(talk) 18:15, 17 February 2006 (UTC)
If you live in the United States, there's nothing to worry about. According to, FDA regulations that took effect in 1994 require produce packers or grocers to provide information on the type of wax coating they're using. This information will say if the food item is coated with animal-based wax, or if it's coated with vegetable-, petroleum-, beeswax- and/or shellac- based wax or resin. --Bowlhover 02:30, 18 February 2006 (UTC)
I do live in the US, and I've never seen this information displayed. Does one have to seek out a manager and ask? User:Zoe|(talk) 23:49, 19 February 2006 (UTC)

How much power are we really using?[edit]

My question is, how much power is being used when one 100watt bulb is on, compared to two 40watt bulbs

I'm not sure I know what you're asking. The watt is a unit of power, so a 100-watt incandescent light bulb uses 100 joules of power per second, while two 40-watt bulbs use 80 joules of power per second (each one uses 40). If you're asking for efficiency, according to the article on incandescent light bulbs, the 100-watt bulb is 2.6% efficient, while the 40-watt bulb is 1.9% efficient. --Bowlhover 04:34, 17 February 2006 (UTC)

The unit of power is Watt but the commercial unit is KiloWatthour(commonly known as unit). The answer for your question:- If you use both bulbs for an hour the 100W bulb consumes 100/1000 * 1 KiloWatthour i.e. 0.1 KiloWatthour. In case of the 60W buld it consumes 60/1000*1.
So the formula for calculating the power consumed is:
Power of the devise (in Kilowatt's)*time (in hours).

Technically, that's the amount of energy being used, not the amount of power. Power is the rate of energy used per time, and is commonly measured in joules / second, or watts. Therefore, energy is equal to the power (or rate of energy use) multiplied by time. It can be measured in watt-seconds = joules (SI), or in kilowatt-hours (1 kilowatt-hour = 1000 watts × 3600 seconds, or 3,600,000 joules). — Knowledge Seeker 05:27, 17 February 2006 (UTC)

Knowledge Seeker, I dont think you read the question. The question was how much power is being used............................ So the second anwer was right. I wrote kilowatt-hours you wrote watt-seconds. I think kilowatt-hours is the commercial and more widly used unit than watt-seconds. 05:57, 17 February 2006 (UTC)

Actually, I did read the question. The questioner wanted to know how much power was being used. Your answer gave the amount of energy being used, not the amount of power being used. The kilowatt-hour and the watt-second (or joule) are measures of energy, not power. Power is the rate at which energy is used, and is measured in watts or kilowatts. The most widely used unit of energy is debatable: kilowatt-hours, joules (watt-seconds), and calories are all used in different contexts. — Knowledge Seeker 06:22, 17 February 2006 (UTC)

Those efficiencies are horrible. I knew lamps were inefficient, but just a few % is really bad. Even the modern fluorescent lamps don't reach 10%. But I see my old friend the arc lamp is the most efficient at up to an impressive 22%. Funny how the the very first electric lamp design turns out to still be the best. Being a Dutchman I shouldn't be to happy about this because it's an Osram invention, not a Philips one (the bloody Germans got us beat again). But the article says efficiency is very low for the short-arc type. So are the long-arc ones the efficient ones? And where can I get one? Oh, hold on, aren't those the ones used in LCD projectors or something? The ones that cost a small fortune and last just a few thousand hours? DirkvdM 18:59, 17 February 2006 (UTC)

"Being a Dutchman I shouldn't be to happy about this because it's an Osram invention, not a Philips one (the bloody Germans got us beat again)."
In my opinion (and this is only an opinion), the people who do the most benefit to mankind should be respected, regardless of their nationality. --Bowlhover 02:05, 18 February 2006 (UTC)

Crystal habit identification[edit]

Artificial growing of crystals can produce quite unique crystal habits

I've recently been uploading photos of various minerals I took at the Natural History Museum (see User:Aramgutang/Gallery), and while I took care to always note what it was that I was taking a picture of, there is one photo for which I can't find my notes (shown on the right). While identifying the mineral just from the photo is probably not possible, I'd appreciate it if someone could identify the crystal habit pictured, so that the photo can be used to illustrate something. The only thing I remember is that the crystals were artificially grown, if that helps. If not, I guess I could always put the picture in the crystal habit article, with a caption among the lines of "artificial growing of crystals can produce quite unique crystal habits". Thanks. --Aram??????? 07:32, 17 February 2006 (UTC)

That looks like a bismuth "hopper crystal" to me. Hope this helps. — TheKMantalk 16:51, 17 February 2006 (UTC)

Pollution in the ocean[edit]

My question is when the ocean is polluted, does the toxic "sink" to the bottom of the ocean or does is "float" on the surface like oil does? Also what are the abiotic factors affecting cells that live in trenches and how does it affect them.

Thank you

Depending on the type, water pollution may sink, float, or dissolve. The floating pollutants, like oil, are the most immediate threat. Sinking pollutants, like mercury, could be a threat to bottom dwelling life, and to us, if we eat them. Pollutants that dissolve, like bleach, could cause locally high concentrations near the source of pollution, but are probably not significant once dissolved evenly among all the world's oceans. StuRat 07:46, 17 February 2006 (UTC)

quantum physics[edit]

i would like to know how the "particle in a squre well" concept can be used to understand the energy of electron in an atom.

Thank you. mani.

It's a model. The particle in a box is easier to solve than a particle in a central potential. Solving produces some of the features of an electron in an atom. Namely energy levels. These are caused by requiring a whole number of half wavelengths fit the space. These are standing waves. Since the energy is related to the wavelength then as the wavelength is quantised then so is the energy. Although the potential of an atom isn't box like, never the less the electron is confined. This confinement also causes standing waves, and therefore quantised energy levels. Theresa Knott | Taste the Korn 11:34, 17 February 2006 (UTC)

inducing dipoles in non-polar molecules!?![edit]

Stumped by this !: How can a non-polar molecule induce a dipole in a nearby non-polar molecule? I need explanation, not answers!!!

Perhaps our article on London force may be what you ar looking for. Theresa Knott | Taste the Korn 11:27, 17 February 2006 (UTC)
Basically, a non-polar molecule is only non-polar on average: at any given instant, the distribution of electrons might not be symmetrical (due to Heisenberg's principle) and this asymmetry can induce an asymmetry in the electron distribution of the molecules around it. Believe me, it works! Physchim62 (talk) 21:44, 17 February 2006 (UTC)

How long can Earth survive!?![edit]

Just curious:- How long can our Earth survive? I mean with all the ice-ages, global warming, pollution and lots of other goodies, i see no reson that human race would last forever. A quick answer would be nice. Please explain all the consequences. A good estimation of how long we are gonna survive would be wonderful! Thank you.

The Wikipedia has two articles (which should be merged) on this topic human extinction and end of civilization. Forever is a long time, and ultimately, we're doomed: see the ultimate fate of the universe (unless we can figure out a way to transfer ourselves into another universe entirely). As to how long we've got, who knows? A supernova's deadly radiation could arrive tomorrow, and we have no way of predicting this. --Robert Merkel 10:34, 17 February 2006 (UTC)
There's no reason why Earth shouldn't go on for billions of years. A bit of climate change is all part of the deal. Whether the human race will survive is an entirely different question, and you need to be sure you know which one you are asking. Notinasnaid 10:43, 17 February 2006 (UTC)
To answer your question literally, how long will there be a planet Earth?, the answer is approximately another five billion years, which is when our sun, having exhausted its nuclear fuel, expands to become a red giant and will probably swallow the planets up to about Mars. That is, unless it is hit by a really mammoth object (about the size of Venus ought to do it), which could shatter the Earth prematurely. However, this is very unlikely, as the only thing in the solar system big enough is another planet, and they're all sitting happily in their stable orbits, nowhere near the Earth.
If you're asking how long will the human race survive?, that is open to speculation. If, tomorrow, a large asteroid (say, about thirty km in diameter) is heading for Earth, there is nothing we can do to stop it, and it will, in all likelihood, wipe out human civilization, as well as a large proportion of the life on Earth (see impact event). However, life is damn tough, and will spring back eventually, although maybe not in its present form (see evolution). Maybe even some humans may survive, but civilization will have to be rebuilt nearly from scratch.
If the Earth does not get hit by any civilization-killing asteroids in the near future, humanity could still almost wipe itself out through a global nuclear war (see nuclear winter). Similar sorts of effects, pockets of humans may survive, but the radiation will make large tracts of the planet uninhabitable, and civilization will be set back several thousand years.
You can see a trend here, can't you? Humans as organism are pretty tough, it would take a lot to wipe out every human on the planet, global warming, pollution and ice ages won't cut it. However, civilization is a bit more fragile, and mass global warming or pollution would put a serious dent in our development, maybe even start setting us back.
If we don't wipe ourselves out with nukes, and manage to set up bases or settlements on other planets, then humanity has a better fighting chance. Statistically speaking, we are about overdue for a civilization-killing asteroid - an impact like the one which killed the dinosaurs happens, on average, about ever 60 million years, and it's been 65 million since the last one. No need to get worried, just noting. If we manage to viably settle (by that I mean self-sufficient settlements, not just bases that need to be resupplied from Earth) other planets, such as Mars, then we would have a sort of 'insurance policy' against an impact. However, we are still a ways away from this - estimates vary, but I would count at least another 30 years, probably more like 50, or even longer.
Once humanity has spread into the solar systems, you can take a breather - the next thing which can wipe humanity out will be the sun dying, which, as I said at the beginning, will likely happen in about five billion years. Plenty of time - by that point, it can be assumed that humanity will have developed interstellar spaceflight, and has expanded to other planetary systems.... beyond that, it's getting hard to predict anything, but, of course, the ultimate limit is the end of the universe. Current theory says that the universe will likely keep on expanding forever, ending in a heat death, a really depressing mishmashed soup of lukewarm gases. However, this theory is still hotly debated, and in any case, the timescales involved are so enormous (possibly on the order of trillions of years) that you don't need to start worrying about that just yet. :) — QuantumEleven | (talk) 11:12, 17 February 2006 (UTC)
Note that having not had a major meteor hit in 65 million years doesn't make it any more, or less, likely than if one had just hit, assuming they are independent events. Some other natural disasters, like earthquakes and volcano eruptions, are not independent events (as one eruption relieves pressure), however. StuRat 17:43, 17 February 2006 (UTC)
Then again, note also that we've no way of knowing whether major asteroid hits are independent events. They do seem vaguely cyclical, which is one of the reasons behind some theories such as "The Nemesis star". Grutness...wha? 02:47, 18 February 2006 (UTC)
I think any series of random events will "seem vaguely cyclical" when viewed in retrospect. That is, if something happens on average every 60 million years, there will be very few instances where it happens twice in the same year (about one in every 60 million pairs of adjacent events). On the other hand, it would be just as rare for the two events to happen exactly 60 million years apart. Given a wide range, though, of say from 6-600 million years between events, most will "fit the pattern", even though this is just the behavior of a random distribution. StuRat 22:30, 18 February 2006 (UTC)
At the risk of being a bit POV - Earth will survive until the sun nears the end of its life, unless we do something to kill it first. The inhabitants of the Earth, though, are on much shakier grounds. I'm an optomist - I think the human race will somehow muddle through. But I doubt our overall level of well-being, technology, or even civilisation as a whole will be as high in 2106 as it is in 2006, given how thoroughly we've stuffed up this planet's ecosystem and how badly we';ve wasted its resources. I also doubt that there will be anywhere near as many humans alive then as there are now. As I said, though - I'm an optomist. A pessimist would not rate our chances of any form of advanced human civilisation getting through the next century very high at all. But no-one can know for certain, and no-one can foresee what advances may be made. In the 1960s the population was preparing for WWIII. In the 1970s, the warning was of ice ages. The general message, though, remains the same: do what you can to help, and hang on for a very bumpy ride. Grutness...wha? 11:23, 17 February 2006 (UTC)
"An optimist believes we live in the best of all possible worlds. A pessimist fears this is true". JackofOz 11:24, 17 February 2006 (UTC)
All my answers have already been given except for one. Considering how far we've progressed in the last, say, 1000 years, we might just find a way to prevent the Sun from destroying Earth in the next billion years or so. That sounds a bit out-of-this-world now, but so did travelling out into space 1000 years ago. Hell, we didn't even know that there was a space to go out into then. Actually, in a billion years we could develop into a species so intelligent that the solution is obvious to a newly born child. If we even bother with getting born that is. Maybe we will all live immortal lives in some information network. But then I'm basing this thought on the Internet and that concept might be considered horribly out of date in just a few hundred years. So I'd say come back to us in a billion years. Maybe we'll know then. Or maybe there will be another DirkvdM telling you something exactly like this, meaning we're still muddling along. DirkvdM 19:15, 17 February 2006 (UTC)
My partner (who got her degree in astrophysics), has said before that with the knowledge we have now and some relatively small advances in technology it would be possible to move the Earth out to the orbit of Jupiter. It involves slingshotting using both the Moon and Mars in some way (don't ask me - she's the physicist, and hey, it is rocket science). Trouble is, of course, it's a 'do it right the first time' thing - and it would only buy time, since once the sun's at that stage, it won't have long left anyway. Grutness...wha? 02:39, 18 February 2006 (UTC)


I keep getting ants in my kitchen. I've tried some commercial repellants but the little buggers keep on coming back.

The article suggests chalk can help. How would I use it? They're coming up from under the house, through a couple of small openings. Do I just smear chalk around the openings?

Are there any other natural remedies that send ants back to their nest and keep them away for a long time?

I should mention that my duties as a committed Wikipedian preclude me from having a spotlessly clean kitchen 100% of the time, which may be part of the problem. JackofOz 10:58, 17 February 2006 (UTC)

I recall one solution being to liberally pour boiling water over the kitchen floor on a regular basis, which is 100% natural but about as effective as a nuke... Shimgray | talk | 11:14, 17 February 2006 (UTC)
Dirt isn't the problem sugar is. Try to clean up all sources of food for the little blighters. Theresa Knott | Taste the Korn 11:22, 17 February 2006 (UTC)
I concur, removing the food is the answer. A few years back, one of my roommates spilled a very large amount of gunpowder tea all over the kitchen floor. Being that all of us living there were lazy/busy college students, no one had any intention of cleaning it up. Within days, we had ants crawling all over the place. In about a week or two, they managed to take away all the pieces of tea (basically, did the cleaning for us), and as soon as the tea was gone, the ants were gone. Unlike cockroaches, ants don't eat everything, so try to figure out what they're after, and clean/seal it up. --Aram??????? 13:39, 17 February 2006 (UTC)
Food is not always the problem. In dry climates, ants come into the house looking for water. You could have an immaculate house, but if they find a dripping faucet or some other water source, they could be coming in for that. Bay leaves and cucumber peels work, too. User:Zoe|(talk) 19:00, 17 February 2006 (UTC)

I have the same thing at the cottage in the summer (Canada). The natural ant stuff with boric acid works great. With a filthy kitchen, you can throw this nice white powder all over the place and practice your soft-shoe. --Zeizmic 12:53, 17 February 2006 (UTC)

Thanks, folks, I'll try those ideas out. But hey, I didn't say it was filthy. (Not that you care, you're never going to see it anyway). JackofOz 14:19, 17 February 2006 (UTC)

I suggest POISON. Specifically, poison they will take back to the nest and kill off the entire colony. While having a spotless kitchen would keep the ant population down, it's impossible to avoid leaving a few food particles that would make a nice meal for an ant. Also, even if it was absolutely clean, ants would still occasionally sweep through the kitchen to check for food. I consider any ants to be unacceptable, so prefer "better living through toxic chemistry". Specifically, I recommend the MAXFORCE ANT GEL brand poison: [9] StuRat 17:22, 17 February 2006 (UTC)

Poison is the best way - but only if you have the right one. So before you waste your money on the wrong type, get your ant variety indentified. I live in Perth (so probably have similiar resources to you). I captured some ants (trying not the crush them, so they are easier to indentify). I then put them in an envelope and went to the Departement of Agriculture (it's a State govt dept, I'm not sure what your equiv. is). After asking at the front desk a scientist came out and identifed the ant variety, wrote down the correct poisons to use (brand names etc) and drilled me on how to set up some traps - to get the result StuRat discussed.--Commander Keane 18:42, 17 February 2006 (UTC)
Assuming you don't have a problem with ants perse but just want them out of your kitchen, you might provide a better source of food (or whatever they come in for) nearby, but outside the kitchen. I'm also assuming the nest is not inside the kitchen because that would make it unlikely this could work. Then again, if the nest is in the kitchen, poison sounds like a very bad idea. Actually, if they come inside the kitchen it wuuld also be. Although that dpends on the kind of poison - what is poisonous to an ant might not be poisonous to a human. Also, I'm just guessing, not speaking frokm experience. DirkvdM 19:28, 17 February 2006 (UTC)
I think this "appeasement" strategy is a very bad idea. With such a good food supply, they would increase population and spread to many nests right outside the kitchen. Then, once the food ran out, you would have many more ants foraging in your kitchen. If you intend to keep feeding them forever, how many doublings of the population do you think you can afford to feed ? As for poison, airborne poisons do worry me, but this form must be eaten to take effect. Just avoid using it as a topping on your hamburger, and you should be OK. StuRat 21:59, 18 February 2006 (UTC)
But one experience I do have is one time, when travelling, I saw a bunch of migrating ants migrate into my backpack to set up a nest there (some carrying eggs gave that away). I knew that if I'd start brushing them off I'd be finding lost ants in my backpack for weeks. So I gently rocked the backpack a few times, after which they were convinced that was a bad place for a nest and moved on. Now it depends very much on the nest if you can do something similar in your situation. Also, these ants are already settled and might need some more convincing. DirkvdM 19:28, 17 February 2006 (UTC)

When I said "repellants" in my question, I actually meant poison (it's supposed to get rid of them, so to me it is equivalent to repelling them - sorry, I wasn't thinking scientifically). The product I've used is Ant-Rid, which contains boron, and has all kinds of warnings about toxicity etc. It's described as a poison they will take back to the nest and kill off the entire colony, just like StuRat said. It seems to work for a little while, but then they just come back. Maybe it's a question of identifying them and getting a very specific poison (thanks Commander Keane). And I can see a lot of sense in removing all possible forms of temptation (but that means some form of discipline ... shudder.) Philosophically I have no issue with ants per se, but I just don't want them as my personal friends. I'm still curious about the chalk solution mentioned in the ants article. Any ideas? JackofOz 22:30, 17 February 2006 (UTC)

Getting rid of a colony once and for all by killing the queen is an attractive possibility, but it doesn't always work. Argentine ants, for instance, have many queens. Those are the ones we have here in California. --Smack (talk) 00:15, 18 February 2006 (UTC)
Look at them closely, if they are Pharaoh ant then you are in a bit trouble. I've had these in my student housing, they require drastic measures to get rid of. (Including the placing of several quite toxic poison boxes, with sugar coated poison to get the poison into all the hives). The problem with these are that they tend to split colonies very rapidly, so it's hard to kill all of them at the same time, and if you can't , they come back fast.

Broken Compact Disc[edit]

I broke one of my CD's with a LOT of valuable documents and pictures in it.Can I somehow retrieve the data?

Help required,desperately.

Thanks in advance.(praying for good news)

This was discussed recently, and the answer seems to be sorry, no, there is no good news. If anything good comes out of it, hopefully you will from now on be sure always to make a backup. Notinasnaid 12:55, 17 February 2006 (UTC)
  • By pure chance a came to this page a few days ago:
On another page related to this I read that breaking the CD in two pieces is not enough to make *all* information on it unreadble. If this is not just marketing hype then you have hopes. Also take a look at this:
It hints at (presumably very expensive) methods used by governement agencies to extract data from a broken CD. I don't know if there are cheaper ways as well. --Gennaro Prota 13:14, 17 February 2006 (UTC)

I would think the pieces could be glued back together. However, the bits at the point of the break would be lost and special reconstruction software would be needed to make the most of the fragmented data that could be read off the disk. StuRat 17:09, 17 February 2006 (UTC)

You'd have to use some pretty sophisticated glue and method for that. The way to read a cd is to spin it around at very high speeds and the glue would have to be able to withstand that. Also, I remember once seeing to my surprise that a broken cd was bent at the breaking line, which would make the glueing very difficult. Thirdly, the reading would have to be done at a very basic level (bit-by-bit without any interpretation), after which those bits would have to be 'glued' together. Actually, I think tha last bit would be easiest. And the last time this was asked someone suggested scanning the cd. You could in principle write a program that folows the grooves on that image and thus reconstructs the broken up bit sequences. It would have to be a very high resolution scan, though. And all this is just in theory. DirkvdM 19:37, 17 February 2006 (UTC)
If you don't mind my asking, how did you manage to break it? I once took a useless CD and bent it through 180 degrees, after which it released back to its original shape and seemed to work just fine. --Smack (talk) 06:01, 20 February 2006 (UTC)
The important question is: how much is the data on the CD worth? A data recovery company should be able to get almost everything back, but will cost several hundred dollars. --Carnildo 22:13, 20 February 2006 (UTC)

Questions about my latest nightmare (& where to share them online)[edit]

I wish to find out because I think I've had my worst nightmare in a while. This place to share nightmares has to also be well-visited, btw.

This last night, I dreamed I was walking up Mid-Campus Drive to Hale Library (I usually ride my bike around campus however), and when I looked at the stopwatch I usually wear, it said 10:30, but the day looked like dawn before sun-up, at 6:30 in the morning. The sidewalks were crowded, but I saw no cars on the streets. As I was approaching Hale Library, I suddenly found myself in an ill-lit classroom. There was Nicole Peck, my Psychology instructor from the waking world, and she went over what pages to read and assignments to do, and handed us copies of half-sheets going over what we're to do by the next class day.

I had trouble reading it, so I tried to use a lighting contraption (I think was a lamp, but how about a flashlight?) It didn't light brightly enough so the girl sitting behind me said, "Hey, use your cellphone. The light on that should work." Then as I was taking out my cellphone, the instructor told the class, "Class, be sure to turn your cellphones to silent mode to conserve batteries! Also, don't drink any milk because if someone has to go to the hospital in the next 40 minutes..." (and something about the hospital not being able to service their patients too well because of a widespread power outage and something else...)


I heard a brief city-wide siren, and a few explosions heard 1/2 second apart from each other. I looked out the window and saw what appeared to be missiles hitting the nearby base of Fort Riley (8-10 miles away). The teacher then announced, "Class, those appear to sound like Nuclear Blasts so..." although I don't remember what she said after that, what I remembered next was praying, "Please God, ensure my survival!" before waking up.


1. I don't know where on Wikipedia would be a good place to share nightmares, so if there are such places, would you care to tell me, please?

You could try Everything2. It is somewhat similar to Wikipedia, but it's not a true Wiki; only editors (roughly the equivalent of Wikipedia admins) can edit others' contributions. Content-wise, it's much more free-form than Wikipedia, and POV and personal voice is encouraged. They even have a Dream Log section, which is probably what you're looking for. --Ashenai 13:25, 17 February 2006 (UTC)

2. If nukes were to strike Fort Riley, about 8-10 miles from Manhattan, how many seconds or minutes would I have to find a basement or suitable fallout shelter?

Your first concern would be the initial detonation wave (usually incorrectly called the shockwave) which would approach you at supersonic speed... at a speed loosely described in Chapman-Jouguet condition. Assuming a very boring speed of mach-2, and a very boring speed of sound of 330m/s, you'd have about 24-30 seconds to find shelter before it hit. You might want to invest in a slide.  freshgavinG???  14:25, 17 February 2006 (UTC)
Note that this means that the detonation wave travels faster than the speed of sound. Since this is the case, you'd better hope that you can see the blast as it happens, because the blast will get to you before you ever hear about it. — Asbestos | Talk (RFC) 14:54, 17 February 2006 (UTC)
Yes. Even watching the news probably won't help, because even CNN won't be on the story until at least 30 seconds after it happens.  freshgavinG???  15:02, 17 February 2006 (UTC)
Assuming it is a surprise explosion (like a terrorist sneaking one in under his coat), then we are talking a bout a very small and slow explosion. If it is a large warhead on a missile, it will be tracked within seconds of launch. So, the question isn't how long you have to get to shelter after the explosion - the question is how long you have to get to shelter after the government decides to tell people that something bad is coming. --Kainaw (talk) 19:55, 17 February 2006 (UTC)
Though I've never heard of a terrorist sneaking a nuke under his coat before.  freshgavinG???  03:36, 18 February 2006 (UTC)

3. How much would Manhattan get damaged by a nuclear strike on Fort Riley? How badly would those in Manhattan get hurt?

4. If a teacher at my university got word that a nuclear strike on Fort Riley was imminent, what would s/he say to the class???

--Shultzii 12:32, 17 February 2006 (UTC)

This is not the place for dream sharing. Anybody with nightmares should train themselves for lucid dreaming. I've done it, and being able to direct your dreams is a joy. --Zeizmic 13:06, 17 February 2006 (UTC)
You partially answered #1, and I thank you for that. Would you and/or anyone care to answer 2-4 as well, plus what sites are appropriate to share nightmares in? --Shultzii 13:14, 17 February 2006 (UTC)

Short answer to 2 and 3: assuming a typical weapon used by (for example) the Russians of about 500kt, it's unlikely that you'd be killed by the blast or the prompt radiation at that distance, though you might get killed by falling glass in Manhattan, and may get some superficial but painful burns if you're out on the street. See this page if you're sufficiently curious to calculate some estimates for yourself. Fallout would depend entirely on wind direction and speed - if you were directly downwind you wouldn't have long, but you'd have some minutes at least. According to this estimate is again, not sufficient to kill you from radiation sickness in the short term. As to 4, who the hell knows? It would depend on the circumstances (whether Kansas was also at risk, who was presumed to be responsible, and so on). --Robert Merkel 13:46, 17 February 2006 (UTC)

You may find our article on Nuclear explosions answers some of your questions. Theresa Knott | Taste the Korn 13:16, 17 February 2006 (UTC)

Trouble with Wikipedia .svg images on a Mac[edit]

I having trouble with .svg images, and I don't know if it's because I'm on a mac or because of the images themselves.

For instance, if I want to copy Image:Svg.svg to my hard drive: I right click on the image and say "Save as". The filename that the mac wants to give the image is 'SVG.svg.png'. Since this is not a .png file (I assume), I erase the .png to make it save as a .svg, and change the File Type from 'PNG' to 'All formats'. However, when I try to open it, both in my image software and on my browser, I get an error with the implication that the image still has a .png tag somewhere in it and is corrupted. Specifically, if I open the image with firefox, I get the error

XML Parsing Error: not well-formed
Location: file:///Users/asbestos/Desktop/Svg.svg
Line Number 1, Column 1:


Indeed, opening the image in a text editor I get a bunch of garbage with a 'PNG' tag at the top. I know, however, that the image's extension really is simply .svg, with no .png hiding anywhere.

Likewise, if I then try to upload the image to the commons, it says the image is corrupted.

Is my computer trying to turn the image into a .png, or is the image itself a .png masquerading as a .svg? I'm confused. — Asbestos | Talk (RFC) 14:17, 17 February 2006 (UTC)

I don't know but I tried it and have the same problem. If i save the file it saves it as a png. If I remove the extension I can't open the file. I'm using a Linux on a PC so it's not a mac thing. Theresa Knott | Taste the Korn 15:06, 17 February 2006 (UTC)

OK I've worked out what's going on. When you click on the above link it takes you to a rasterised version of the svg. What you see is actually a png image. On the image page (lower left of the image) is a link to the actual svg file called svg.svg. If you save that file you get the real svg. Theresa Knott | Taste the Korn 15:25, 17 February 2006 (UTC)

I believe a similar question was asked at a ref desk here about a month ago. DirkvdM 19:39, 17 February 2006 (UTC)

What chemicals are brain cells missing that allows other cells to replenish?[edit]

I'd like to know what brain cells don't have that other cells in your body have, that allows replenishing and regeneration. In an effort to make brain cells regenerable (or regeneratable?), I'm sure medical research is in progress about it. What would it take for brain cells to replenish like other body cells? --Shultzii 16:38, 17 February 2006 (UTC)

Your question is a bit, erm, naive. Allow me to help refine it a bit. Neurons (the cells that compose your brain, spine, and nerves) do not undergo Mitosis or Cytokinesis, but can be replenished by converting stem cells into replacements for lost or damaged neurons (that's why stem cell research is so promising as a treatment for degenerative diseases). The reason they do not undergo mitosis is that your brain is a very, very delicate machine. When you were a fetus, your brain went through a great "pruning" (I cannot think of the correct term off the top of my head) that carved it down into a functional unit (think of it as the human equivalent of cutting an overgrown tree into a well-shaped topiary). The cells in your brain cannot simply start reproducing willy-nilly, or it would cause serious problems with the neural pathways (with cells that aren't supposed to be there suddenly appearing). Raul654 16:45, 17 February 2006 (UTC)
Lets hope the stem cell research flourishes and makes a breakthrough that I want. Only if Hwang Woo-suk's "results" were for real, and never fabricated, would this medical field have been farther along today. --Shultzii 17:12, 17 February 2006 (UTC)
Some are working on it :) According . There is some evidence for (very slow) naturally occuring brain growth. Some Hormones have been identified, but still no clinical uses yet.DanielDemaret 21:44, 24 February 2006 (UTC)

DVD and software question[edit]

I am currently using Windows Media Player and Power DVD (it happens on both), and when I press the "Print Screen" button on my keyboard and paste it into MS Paint, the image I thought I would get did not appear; merely a "mirror" or paused image of the part of the film. What I would like to know is, if you don't mind, this just a way to avoid copyright violations. And are there any possible ways to avoid this? Thank you. KILO-LIMA 17:20, 17 February 2006 (UTC)

Well there's the smart-assed answer: Avoid copywrite violations by not copying copywrited works. Or the Wikipedian answer: We don't give advice on how to perform illegal actions. Or the honest answer: Dunno.  freshgavinG???  17:28, 17 February 2006 (UTC)
Sorry, wasn't clear enough. I would like to get a photo for uploading onto Wikipedia. It would be under the screenshot template, and thus, qualifies as fair use. KILO-LIMA 18:06, 17 February 2006 (UTC)
I don't think being a screen shot is an automatic claim for fair use. That makes no sense: any copyright material could be on someone's screen, does snapping it absolve anyone from copyright? Notinasnaid 18:22, 17 February 2006 (UTC)
I assume there's some kind of rule about the content of the screenshot, e.g. it has to be an in-game or screenshot of a video process. Screenshots of programs run in windows seem to be allowed but I imagine shots of your desktop aren't. Fair use requires a lot of common sense... I don't understand a lot of it myself.  freshgavinG???  18:44, 17 February 2006 (UTC)
PowerDVD has a screenshot feature you can use that will copy the frame to the clipboard. I think you press the "T" key. ? ?i?ff?? 19:41, 17 February 2006 (UTC)
And, btw, fair use often has to do with the quantity involved. Taking a screen-shot of the When Harry Met Sally orgasim scene for a Wikipedia article that is otherwise image-free would probably be fine. But posting several copyright images from The Phantom Menace in a plot overview would not be fine. Resolution matters too (keep them small-ish). See this template for more detail:

This image is a screenshot from a copyrighted film, and the copyright for it is most likely owned by the studio which produced the film, and possibly also by any actors appearing in the screenshot. It is believed that the use of a limited number of web-resolution screenshots

qualifies as fair use under United States copyright law. Any other uses of this image, on Wikipedia or elsewhere, may be copyright infringement. See Wikipedia:Fair use for more information.

To the uploader: please add a detailed fair use rationale for each use, as described on Wikipedia:Image description page, as well as the source of the work and copyright information.

Reference desk archive/Science/February 15-21 2006 You could simply try disabling the hardware acceleration. The problem is probably simply that the code which PrintScreen uses is unable to read from the overlay the hardware acceleration of video playback often uses. --cesarb 20:19, 17 February 2006 (UTC)

For Windows media player, this site tells you how to do it. - Akamad 20:54, 17 February 2006 (UTC)

I've always had this little trick. If you have two media player programs on your computer, open both and get both to play the DVD. Then you can print screen all you like. enochlau (talk) 01:56, 18 February 2006 (UTC)

anodised and teflon cookwear[edit]

I would like to know the difference between the two and if teflon is normally included in anodised cookwear. thanks

According to our fine article on anodising, it involves forcibly oxidising aluminium to build up a layer of aluminium oxide on the surface. Aluminium oxide is very durable and extremely hard; it occurs naturally as corundum, and finds applications in sandpaper. The article doesn't say, but I gather that it's used on cookware to prevent scratches.
Teflon (polyethylene terephthalate), on the other hand, is deposited as a coating ("painted on", you might say). I don't think it provides any durability, but rather it resists adhesion. --Smack (talk) 17:43, 17 February 2006 (UTC)

Note that Teflon can be toxic when overheated, see Teflon flu. StuRat 18:25, 17 February 2006 (UTC)

There have also been recent reports indicating that Teflon may be a carcinogen. User:Zoe|(talk) 19:02, 17 February 2006 (UTC)
And of course, there have been studies that link aluminium to the progression of Alzheimer's disease... Notinasnaid 19:37, 17 February 2006 (UTC)
I don't think there are studies linking aluminium cookware to Alzheimer's. Rather, it was when Aluminium was used in hemodialysis machines. - Cybergoth 21:46, 17 February 2006 (UTC)
Does the "Teflon flu" really exist, or did User:StuRat just make it up on the spot? (I'm not disputing the toxicity of Teflon, but according to the Teflon article, it's not much of a threat, and I want to keep it from masquerading as one.) --Smack (talk) 23:43, 17 February 2006 (UTC)
No, I didn't make it up. The effect of toxic gases released from overheating Teflon was documented in the main article under Teflon#toxicity. If you do a google search on "Teflon flu", you will find 1400 matches. StuRat 01:31, 18 February 2006 (UTC)
I don't know about "TeflonFlu"... how about "TeflonStu"? :P Cybergoth 01:34, 18 February 2006 (UTC)
I get 1320 hits. Looks like a dubious, ad hoc coinage, and a false analogy with influenza. Again, I'm not trying to deny the toxicity of Teflon under unusual circumstances; I'm just questioning the term. --Smack (talk) 06:05, 20 February 2006 (UTC)
The article does explain that it's called that because of flu-like symptoms, and has no other relationship with influenza. Note that many other common English terms are more wrong than this...a koala bear isn't a bear, for example. StuRat 07:02, 24 February 2006 (UTC)
The popularity of misnomers doesn't justify making a new one. Try "Teflon sickness" or something like that. --Smack (talk) 23:48, 24 February 2006 (UTC)

using PC as a telephone and fax machine[edit]

I have a PC.It has printer and telephone lines attached.How can I use it for receiving faxes and as telephone conversation recorder.

If you have a fax-modem and are running a recent copy of Windows, you simply have to go into the Control Panel, and Add a Fax Printer. It should basically step you through the necessary configuration. I don't know what would be required for the recording of conversations. --LarryMac 17:57, 17 February 2006 (UTC)
As LarryMac stated, a fax printer is easy to add. For recording phone, every program I've seen required you to use speakers to hear the other person and a microphone to talk to them. Now that people are doing a lot of this internet phone stuff, there are some nice speaker/mic combos that look like a regular telephone handset. Just Google for "phone recording software". You are looking at $60-100 for anything reasonable. --Kainaw (talk) 19:42, 17 February 2006 (UTC)

EDTA poisoning[edit]

What would happen to you if you somehow overdosed on EDTA? —Keenan Pepper 18:57, 17 February 2006 (UTC)

  • Are you just waiting for someone to say, "Your dead body would be very well preserved"? --Steve Summit (talk) 21:33, 17 February 2006 (UTC)

Hypocalcemia and possibly death. See also chelation therapy and this article. - Cybergoth 21:44, 17 February 2006 (UTC)

I think in an overdose situation, anemia would be more of a risk. Hypocalcemia is certainly a risk with chronic exposure. Physchim62 (talk) 21:51, 17 February 2006 (UTC)
Do you mean the EDTA would steal the iron away from hemoglobin, so to speak? —Keenan Pepper 22:24, 17 February 2006 (UTC)
No. In an acute overdose, you could get low iron but you would not become anemic, at least not right away. EDTA cannot "steal" the iron from hemoglobin. I think hypocalemia is more likely to happen in an acute overdose. - Cybergoth 01:31, 18 February 2006 (UTC)
  • If the dose is high enough, it would cause lysis of certain cells, especially blood cells if it got into the blood stream. - Mgm|(talk) 14:28, 19 February 2006 (UTC)

which one is first?[edit]

  • does it involve:Bondary Conditions?? If Yes,Why???--HydrogenSu 19:35, 17 February 2006 (UTC)

for the in a box problem, Starts from

,why do we solve

first ,

then do

?--HydrogenSu 19:33, 17 February 2006 (UTC)
  • I'm sorry, but this sounds like the kind of homework question one might be assigned, were one taking an intro course in quantum mechanics, and it looks like you're asking one of us to do it for you-- 20:12, 17 February 2006 (UTC)
What kind of homework question would that be? For HydrogenSu are you serious? You appear to be asking why A + B? rather than B + A. Guess what. it's doesn't matter. Theresa Knott | Taste the Korn 00:29, 18 February 2006 (UTC)
As far as the A*Sin + B*Cos thing, the wavefunction can be aproximated as two terms of opposite charge aproximated by ? ~ estuff*(some const), where the absolute square of the constant represents the prob of the particle having momentum in the (+)x or (-)x direction, the constants used are A and B, making the expression A*e(+)stuff + B*e(-)stuff, and for what that has to do with your question, please see Euler for more information-- 18:19, 18 February 2006 (UTC)

Did you know there's a limit to free questions for each person (3 in one day)? After that, it's 5 bucks a pop. --Zeizmic 23:11, 17 February 2006 (UTC)

Why? Just . JackofOz 03:58, 18 February 2006 (UTC)
. You know what, I think I figured out HydrogenSu. If you read his questions from bottom to top, they almost make sense!  freshgavinG???  05:42, 18 February 2006 (UTC)

it was not a homework,but a question when I went class,I found it. The teacher said how to solve it only but seemed to miss its details ,I guess. So proposed it for study here.--HydrogenSu 19:49, 18 February 2006 (UTC)--HydrogenSu 20:59, 18 February 2006 (UTC)

  • I guess my teacher wanted to solve it by technonogy. But seemed to be absent some physical meanings. . Its parts of expansion(by ignoring some Imaginary)part:sin* and cos* are each for:

and To Solve A.sin* first ill easily get Real part :Re{e^x}=cosx-----is exactely quite as waves' values of an observe physical property. (While writed to those,I was still some....didn't known how to discribe it...Maybe it was for fun in physics.) I suppose that when estimating some waves' functions by some real property,like group velocity(ies) and somthing like above,it might be done by taking Re{something,stuff,....}. And the other is analysing by differentiation.  ?Not sure I am???Woow...?

--HydrogenSu 20:08, 18 February 2006 (UTC)--HydrogenSu 20:21, 18 February 2006 (UTC)

  • I don't quite understand the question anymore, maybe you want to post the origional homework problem word for word?-- 20:14, 18 February 2006 (UTC)
e sky is blue, it makes me cry ... --DLL 20:39, 18 February 2006 (UTC)
I guess that kind of solution by "tachnology" involved "Re". As I know,phase velocity is waves variating up-down,up-down.... and is about that Im parts gotten after exp{something} expanding. But group velocity is not and is about Re{*}.(Thus group velocity can be differential----one of the reasons by math expressed -----Maybe )--HydrogenSu 20:40, 18 February 2006 (UTC)

WiFi range and obstacles[edit]

I've got a wireless setup to share my Internet connection with some house mates. The distances aren't too big - 20 m at most, and the WiFi article mentions a range of 45 m. The furthest person didn't get any reception until I moved the transmitter less than 2 m, after which the signal jumped way up (then again, I don't know what sort of scales these things give - they're 'idiot proof' or something, meaning they simply don't quantify the info with a decent unit of measurement - bloody irritating). Now the change in distance was under 10%, so it can hardly be that. But first, there was a row of lp's in the line of the signal (actually right next to the transmitter). Does vinyl stop the radiation? Or steel reinforced walls maybe? Plastic or metal - what works as an isolator for this radiation? DirkvdM 20:08, 17 February 2006 (UTC)

  • Just about anything in between the router and the target machine, other than open air, is likely to cut the range by some absurd amount-- 20:22, 17 February 2006 (UTC)
Here's a good article. --LarryMac 20:27, 17 February 2006 (UTC)
For me, my microwave is the worst culprit. When the kitchen is between me and the router and the microwave starts up, I immediately lose the signal. When the microwave stops, it works just fine again. Similarly, I was just in NY. I leeched some guy's wireless to avoid paying $9/day for the hotel's wireless. (Thanks takahiro!) It worked best at night - signals travel better through cold dry air. Every now and then, for no reason I could see, the signal would quit for 2-3 minutes and come back at full strength. I blamed some microwave near me, but I can't say that was the true culprit. --Kainaw (talk) 20:35, 17 February 2006 (UTC)
You know, people who operate open wifi networks near hotels are almost certianly phishing for personal data, and yes, microwaves are the worst-- 20:41, 17 February 2006 (UTC)
Yes, I know. Too bad I was just using SSH to servers I already had a shared key with. Maybe I should have checked my bank account without SSL while I was there - then it wouldn't be like I was stealing bandwidth without giving something back. Well, I was nice enough to not tunnel X. --Kainaw (talk) 03:33, 18 February 2006 (UTC)

The wireless phones are bad, too. Everything is bad. As I've said many times here, I find that a dual frequency (a+g) works best because it can work around those corners. --Zeizmic 23:09, 17 February 2006 (UTC)

Obstacles are not the biggest problem for wireless communication. The big issue is something called "multipath interference." Transmitting a radio signal in an enclosed space is a bit like talking in a gymnasium - it's hard to tell the real signal from the echos. --Smack (talk) 00:05, 18 February 2006 (UTC)
Ah, but that would only be a problem if used in the same room I suppose. As it happens the transmitter and receivers are in different rooms. Maybe it would help if the far wall at each receiving room was non-reflective (what kind of material would that be?). There is no microwave oven in any of the paths, so that's not it. Zeizmic, the transmitter uses both b and g (not a and g). Should the receivers also be set to receive both or do they do that automatically? And, as I asked, what kinds of materials block the signal most? Water? (I had some distilled water bottles next to the transmitter.) Plastics or metals? DirkvdM 09:46, 18 February 2006 (UTC)

Oh, a challenge to my brain! Yes, it is a+g, with a b thrown in (slower g). Here's the link [[10]] --Zeizmic 13:52, 18 February 2006 (UTC)

I've got a linksys wrt54g, which has b and g, not a. DirkvdM 21:03, 19 February 2006 (UTC)


Recently, wikipedia users have answered some very stupid questions. For example, someone posted multiple questions about cuting bone, aquiring a bomb, and disposing of bodies. Why were you stupid enough to answer those questions? *Max* 22:15, 17 February 2006 (UTC)

Because it feels bad to be ignored. Even a joke is better than nothing. Also, why do you not want users to answer "stupid" questions? --Bowlhover 01:21, 18 February 2006 (UTC)
because information wants to be free, and teh terrorists will know how to use google too, so there is not really any danger in answering questions here the answers to which are plastered all over the internet. dab () 22:18, 17 February 2006 (UTC)
WP:AGF ? User:Adrian/zap2.js 01:30, 18 February 2006 (UTC)

Yes, but did we answer them well? Who knows, MUUHAAHAA! --Zeizmic 23:05, 17 February 2006 (UTC)

I answered those questions for two reasons: First, they were very stupid questions with obvious answers. Second, anyone stupid enough to not know the answers would cause more harm to themselves than anyone else. Now, if someone were to ask a intelligent questions about a crime, I wouldn't answer. An example could be: How can I hack the CIA network and make it appear to even the best computer expert that the hack is coming from someone else so they will be the one who is investigated? (No - I am not actually asking this question.) --Kainaw (talk) 03:31, 18 February 2006 (UTC)
I would answer intelligent questions about crimes, like the one you gave as an example, if they're easy to answer. For your example, I'd say something like (but more detailed than) "First, find out the IP addresses of the CIA computers and port-scan them. Then, make your computer use a fake IP address to do the hacking. Finally, try a variety of computer hacking techniques, like fishing for blank passwords, to gain access to the computers." You don't have to list all the steps in detail--just a brief, generic answer would be OK. --Bowlhover 04:02, 18 February 2006 (UTC)
I'm assuming that sample answer to the sample question is one of those "joke replies" you suggested  :) User:Adrian/zap2.js 05:19, 18 February 2006 (UTC)
Perhaps you've heard the phrase "there is no such thing as a stupid question". Actually this is flawed (I think it was Dogbert who said "What sort of question do stupid people ask? Do they become smart briefly to ask the question?"). However, I saw this as a mischievous question ("trolling" to use the current jargon) rather than an inherently stupid one, and I thought the answers were suitably mischievous too, without rising to the obvious bait in the way you finally did... Notinasnaid 09:32, 18 February 2006 (UTC)
Inherent in the asking of a question, any question, is an acknowledgment that you don't have as much knowledge as the other party, and you're wanting to fill that gap. That you are seeking to increase your knowledge is a positive thing. People have different levels of knowledge; those with less knowledge ask questions and those with more knowledge answer them. Any characterisation of another person or their question as "stupid" reflects only on the attitude of the person making this judgment. Sometimes you get an answer to a question and you realise you could have worked that out by yourself, but often that is only apparent in retrospect. I agree with Notinsnaid on this. JackofOz 20:13, 19 February 2006 (UTC)

February 18[edit]

Hard Drive Clicking[edit]

Hi, in August 2003 I purchased a Dell Inspiron 5100 laptop. Just lately, I've been having a problem where a clicking begins near where the hard drive is housed in the laptop. There doesn't seem to be a distinct cause as it happens both when I'm doing intensive video work and when there's only a desktop with minor background tasks running. When the clicking begins, the whole system grinds to an unusably slow pace, but a hard shut down and then booting back up fixes it at least temporarily. I've taken out the hard drive and it does sound like it could be making the clicking when I gently turn it over. The hard drive isdescribed as HARD DRIVE, 60GB, I, 9.5MM, 4.2K, FUJITSU, V40 on the dell site. I've looked there and on google but have found nothing describing this problem. I've backed up all the data I want off the drive in case its in its death throes (but this has been happening for ~1 week). I'm kind of stumped as to where to go from here. Should I bite the bullet and buy a new drive, hoping that fixes the problem? Or should I try something else first? Ideas? -Anonymous

P.S. If this is the wrong forum for this kind of question, where else should I try asking it? -Anonymous

I've had this happen to me with several hard drives. Clicking usually means there is something physically wrong with the HD. On one occasion, I was able to bring back a HD from the dead by reformatting and identifying the bad sectors, but it wasn't long before it started clicking and it died again (new bad sectors). I would recommend getting a new hard drive. Anyway, WP:RD/SCI seems like a fine place to ask a question like this. — TheKMantalk 03:21, 18 February 2006 (UTC)
The clicking sound is a result of strange movement in the "arms" of the reader, or possibly the motor spinning the disk. I have a Panasonic walkman that has something messed up with the motion of the laser (happened 10 days after the 1 year warranty ran out) and its incredibly loud when it scans the CD at first (which now can take up to 10 minutes depending on the CD). Still going strong though, 1 year later! Generally, though, this kind of problem will get worse if you don't do anything about it, and with hard-drives as cheap as they are now, I'd say you're best off buying a new one. You could always keep the old one hanging on as a slave, and use it for storing non-essential stuff.  freshgavinG???  05:40, 18 February 2006 (UTC)
I also had that with a hd that kept on crashing. You bought the thing 2 1/2 years ago. Maybe there's still a warranty on it. In the EU that has recently been made into a general law that effectively makes manufacturer's guarantees invalid, so don't be fooled if the supplied warranty states something like one year - ignore that. I believe that for computer equipment the period is 2 or 2,5 years, so you might just be in luck if you're quick enough. Make sure you follow the rules, though, such as returning the equipment to wherever you bought it, not to the manufacturer (a mistake I once made). The again, something bigger than a 60 GB hd wouldn't cost too much. DirkvdM 09:59, 18 February 2006 (UTC)
Unfortunately I'm in Japan, which means no-one really questions the validity of things like warranties, and they don't complain about them either. Then there's the fact that a 3 year warranty here probably costs 3 times what it would in Europe... they make good money.  freshgavinG???  10:50, 18 February 2006 (UTC)
Interesting, I also have a Fujitsu HD (40GB, model MHS2040AT) in my laptop, from around the same timeframe (bought in June 2003) and it's been doing the clicking/crashing thing for about a year and a half now, usually after 24-48 hours of uptime. I've found that if it starts happening if I leave the computer unattended for a while, I will come back to a blue screen STOP error (in Windows 2000), does that happen to you as well? I've started backing up all my data to an external drive, in case the Fujitsu finally kicks the bucket. Maybe you should install a Self-Monitoring, Analysis and Reporting Technology program and see if any of the values are dropping into dangerous territory. If I don't immediately pull the plug when I hear the clicking, the "Load/Unload Cycle Count" usually drops by a point or two (now at 46/100), and from one episode the "Current Pending Sector Count" fell to 90. I'm not completely sure what those values actually mean, but low values are a Bad Thing. I'm just amazed my HD still works after all that time. --pj
AFAIK, pending sector count is bad blocks, and head load/unload is what's doing the clicking — the head going to its parking place and back. With SMART, lower numbers are worse, so if the number reduced, it's not a good thing (note, however, that some of these numbers fluctuate a bit; that's normal). If your SMART tool can show the raw values, the raw value for pending sector count is the number of bad blocks. --cesarb 12:48, 18 February 2006 (UTC)

Thanks for all the input. Unfortunately the entire computer is no longer under warranty and I live in Canada. Yeah, I also return to a bluescreen when I'm away for a while (I assume it did its clicking thing then died). Every time the clicking has happened while I'm near the computer I've shut it off manually. Mostly I just want to be 100% sure its the drive before I buy a new one. I'm 98% sure, as its not the CD/DVD drive (the sound's not coming from there) and there's no other moving parts AFAIK. The reason I have any doubt is that the computer slows to a crawl when it happens, which doesn't seem like something that should be associated with a hard drive failure to me. I'll try that diagnostic tool and see what I can see though. Thanks everyone. -Anonymous

With my most recent hard drive crash a few months ago, my laptop's hard drive started clicking, crashed, and was unable to properly start up again. I was able to remove the hard drive and hook it up to my desktop to backup my data. While I was able to get all that I needed, my desktop slowed to a crawl whenever the bad HD was accessed. I tried reformatting that HD, but to no avail. (good thing I let the salesman talk me into an extended warranty). — TheKMantalk 18:34, 18 February 2006 (UTC)

Ok I just installed a SMART, and without the clicking happening the first thing it noticed is that after a cold boot the HD temp quickly rose to 47 deg C. The SMART tool by default sets off an alarm at anything over 42 deg C. Any processing beyond simple web browsing brought the temperature up by a couple more degrees. So, another question arises - is this a drive failing on its own or has it been baked to the point of failure by a faulty cooling system? I don't want to install a new drive only to bake that one too. To cover the simple stuff, the fan is free from clogging and the laptop is elevated ~ .5 cm off a hard surface by its feet for airflow. Where would you go from here? -Anonymous

Some kinds of hard drive problems do cause its temperature to rise. Also, slowing down the computer to a crawl if the harddisk is dying is normal and expected, because of the multiple retries required to read a single cluster (these same retries are associated with the clicking). However, it's also possible that the high temperature is normal for your system, only that you never knew; and yes, high temperatures can also be the cause of premature disk failure. --cesarb 13:55, 19 February 2006 (UTC)

House question[edit]

On watching a recent (for the UK) episode of House, I'm left with a "why didn't they catch this much earlier?" feeling. The patient, it eventually transpired, had been exposed to a radioactive source which had killed his bone marrow, devastating his immune system which in turn caused or permitted all the other complex symptoms that had vexed the team for the first three quarters of the show. But, I'm left asking, wouldn't this have caused a huge drop in the patient's white cell count, something that would be apparent from his CBC. If ER is anything by which to judge, CBCs are thrown around whenever a patient has anything wrong with them (bar a few obvious meatcleaver-to-the-brain things). -- Finlay McWalter | Talk 03:07, 18 February 2006 (UTC)

(Oh, I forgot to actually ask the question...) So, would they have done a CBC, and if so why wouldn't the CBC catch the white cell problem? Medical complications or dramatic licence? -- Finlay McWalter | Talk 03:08, 18 February 2006 (UTC)
I'm not an expert in radiation poisoning (and I don't watch this show) but... the doctors would likely have done a CBC. Yes, CBCs are "thrown around' often and yes, it would show a low white blood cell count (WBC). It is possible that the drop in WBC is a delayed effect and only appeared after a couple of days. Also, there are many causes of low WBC, radiation sickness not being the most common. - Cybergoth 03:36, 18 February 2006 (UTC)
Didn't see the show, but... You can't get into a hospital without a CBC. Downright impossible. And one will likely have one repeated at least weekly while hospitalized. But the WBC count might not drop for several weeks after an acute massive radiation exposure. So I think they might have managed this OK (unless he was getting infections before the neutropenia appeared). (See here for info on acute radiation syndrome. I can see how it might be perplexing if there was no reason to suspect radiation exposure. - Nunh-huh 05:28, 18 February 2006 (UTC)
It's the sort of mistake that can easily happen if you let Bertie Wooster run your hospital. Grutness...wha? 07:31, 18 February 2006 (UTC)

Lucid dreams[edit]

Sometimes when I wake up in the morning and go back to sleep again, I enter a lucid dream while being fully aware that this is a dream. I could end the dream whenever I wanted. (By the way, I wasn't trying to induce the dream--it just occured.) Two questions regarding this:

  1. Can most lucid dreamers end their dreams voluntarily?
  2. How did I accurately estimate the time that was passing in the real world, while still dreaming?

--Bowlhover 03:45, 18 February 2006 (UTC)

This is the most common time for people to be able to control their lucid dreams. In fact, you can be dreaming when more-or-less awake at this time. These dreams can be easily "killed" by just opening your eyes a fraction. Someone with more knowledge will be able to tell you more, but I suspect that the opening of the eyes triggers a change in brainwave rhythms. The tricky one - and still a controversial one - is lucid dreams at other times of the night. Even their very existence is questioned by many, and not a huge amount is known about them. Grutness...wha? 07:35, 18 February 2006 (UTC)

I can only speak from my limited personal experience of lucid dreams. (1) I have read that you can just repeat your own name, although I have never tried this. Forcing my eyes open usually works, but more usually I jump from a high window or in front of a train. (This wakes me with a jump and is not very pleasant, but it is quick and effective.) (2) In my experience this is very difficult. Time seems to have quite different rules in dreams. --Shantavira 17:34, 18 February 2006 (UTC)
Answer to question 1: In general, yes. I don't try to induce lucid dreams, nor have I had many, but the easiest thing to do in one (for me) is to wake up, by just "opening my eyes". It's a weird "opening my eyes", like I can control the eyes of me in my dream and my separate real-life eyes. I'm sure more experienced lucid dreamers can do it. Answer to question 2: I've tried to do this. It's definitely not possible for me. In one lucid dream, when I looked at my watch, the time on it was frozen, except when I looked away and looked back, then the time was completely different. So that doesn't accurately allow me to measure time. There are some very good lucid dreamers out there, though, so I wouldn't be surprised if someone managed to do it after a lot of practice. I've found that everything feels like it's going too fast in lucid dreams, and that I don't have much time to do whatever I want. So that might mean something. -- Daverocks (talk) 03:09, 19 February 2006 (UTC)

Watertight compartments?[edit]

On the watertight compartments of a Chinese junk:

Another characteristic of junks, watertight compartments allowed to reinforce the ship structure and to preserve its integrity even in case of holing. This innovation was recognized and adopted in the West during the 18th century.
"As these vessels are not to be laden with goods, their holds may without inconvenience be divided into separate apartments, after the Chinese manner, and each of these apartments caulked tight so as to keep out water" (Benjamin Franklin, 1787).

Have any scholar ever examined these compartments? If you want to build REAL watertight compartments, you need to make them almost as thick and water-tight as the ship's hull. It takes much less money if you only build "livingroom-like compartments" but they are useless if the ship's hull breaks as thin walls might not be able to withstand the water pressure at its lower part.

A small wooden boat may benefit from thin and cheap compartment walls. However, if you build a ship as large as Zheng He's "Treasure Ships", you need really thick and sturdy walls. Otherwise, the walls may break or move under increased water pressre. The inner walls may not need to fight the crushing waves, however, they still need to withstand static water pressure. -- Toytoy 04:03, 18 February 2006 (UTC)

I think you yourself just provided the answer. A localised blow is much more destructive than an evenly spread constant presure. The hull would have to withstand the latter (including icebergs, preferably), whereas the compartment wall would only need to withstand the former. And the cargo area of a sailing ship doesn't usually go deeper than a few metres. I see a bigger problem with doors, if these spaces are indeed to be used as 'apartments'. Water would likely seep through, so it would only buy people some more time (which can still be a big lifesaver, though). Of course, the doors (and fittings and such) could be made water resistant, but combining that with ease of use as a door could be costly. Don't know, just guessing. DirkvdM 10:12, 18 February 2006 (UTC)
Most ships are also equipped with pumps, so can stay afloat indefinitely so long as the pumps can remove water as fast as it seeps in. StuRat 17:20, 18 February 2006 (UTC)
I just wonder how could they, in the 15th century and with only wooden boards available, built so many large seaworthy ships. Personally, I don't think these compartments were watertight. To make a large ship truly seaworthy, you must make the compartment walls reasonably waterproof and be able to withstand at least static water pressure. With only human power, pumping out water could only help so much. It takes much more time, money, expertise and materials to build watertight compartments than livingroom-wall compartments.
A ship's hull can withstand pressure because it's shaped like an arch. However, compartment walls are flat and subject to a very strong shear force at their joints between the wall and the inner hull. You can always strengthen the joints but ... . I guess these ancient ships were only able to travel near land. If anything went wrong, people jumped into water and tried their best to swim or got eaten by sharks. -- Toytoy 01:24, 19 February 2006 (UTC)
If I were to design the compartment walls, they would use an arch shape, like so:
               *******          *******        
                 ***              ***
                  *                *
                 ***              ***
               *******          *******
StuRat 07:12, 24 February 2006 (UTC)
Indeed lots of ships were wrecked and that may be one reason they stayed close to shore. So that made the voyages to America rather dangerous, especially when they didn't even know there was a continent there. The Vikings had the advantage that they could island-hop there. DirkvdM 10:13, 19 February 2006 (UTC)


I've already asked a much more specific and well worded question on the general help desk, but I have little confidence in their answering abilities and thus I will ask a different, and very noobish question here which will probably serve much better purpose.

Why isn't wiki recognizing my .js .css etc. code as real code?  freshgavinG???  04:58, 18 February 2006 (UTC)

No, this doesn't seem to be the real problem actually. Ugh nevermind.  freshgavinG???  05:25, 18 February 2006 (UTC)

Economical thikness of insulation[edit]

I wont equation to how calculate economical thikness of insulation

In English, it sounds a little bit rude to say "I want blah blah". Maybe you should ask your question like this: "I was wondering how to calculate the economical thickness of insulation. Can anyone help me?"  freshgavinG???  13:45, 18 February 2006 (UTC)
Give the guy a break. Obviously his English isn't too good and maybe he even had to work up some courage to ask this in English. And if he's Japanese there's a good chance he won't dare come back again after being told off like that. Or she, of course. :) DirkvdM 19:04, 18 February 2006 (UTC)
I was actually trying to lightly suggest a change of wording. Can you think of a better way to inform him/her?  freshgavinG???  16:59, 22 February 2006 (UTC)

I can't give a specific answer, but let me bring up some issues. This is an optimization problem, and the results will depend on how precisely you define the problem. If, for example, you choose to buy the amount of insulation which will pay for itself in the shortest time period, then you will want a relatively small amount of insulation, perhaps even none, if your home is already reasonably well insulated. If, on the other hand, you want to save the most amount of money total and plan to live there for many years, then more insulation might be in order. Factors that would go into the decision are the cost of insulation, the projected future cost of heating and air conditioning the home, the current level of insulation in the home, the effectiveness of the new insulation, the cost of installation, how long you expect to live in the home, projected future climate in the area, projected increase in resale value of a better insulated home, and the cost of the money used to pay for the insulation. The cost of money would be interest if you are borrowing it, or the opportunity cost, otherwise. StuRat 17:11, 18 February 2006 (UTC)

Battery types[edit]

What would happen if you used an (old style, probably not very intelligent) Ni-Cd battery charger to charge NiMH batteries? Ojw 12:46, 18 February 2006 (UTC)

The really old and slow chargers are ok, since they just trickle the current. Much worse are the high-speed nicad chargers. As with all such batteries, the real damage occurs when you overcharge. Since these batteries are expensive, I would get a good charger. I found that the best are ones that monitor each battery, and are relatively fast (1 hour). --Zeizmic 13:57, 18 February 2006 (UTC)
How intelligent can a battery charger be? Now if you were talking about a smeggin' toaster, that would be different. :) DirkvdM 19:07, 18 February 2006 (UTC)
A battery charger built into a device which will remain nameless on the basis of being an imminent gift. Which explains why I have the NiCd charger, although I have have no idea whether it's more intelligent than (say) an nVidia driver... It's missing batteries, and I have loads of NiMH ones laying around, which explains the choice of battery. While I understand the most "sensible" answer is to buy a replacement for one of the items, that would presumably involve non-zero cost. Hence, my wondering if they can safely be used together. Ojw 21:04, 18 February 2006 (UTC)
If you have loads lying around, why don't you just try? Are you afraid the charger could be damaged? Also, I still don't get what you mean by 'intelligent'. I've heard some misuse of the term but this sounds ludicrous. I thought you were joking. Do you mean to ask if it could detect what type the batteries are? That's not intelligence. At most it's intelligently designed and even that is an overstatement (and no, I'm not referring to some born again creationism :) ). DirkvdM 10:20, 19 February 2006 (UTC)

L vs Lx[edit]

Since this specifies linear momentum, ?x = -ihd/dd in terms of x the component, and since the wave function is also specified to the quantum number nx shouldn't L actually be Lx?-- 14:28, 18 February 2006 (UTC) (not really a question, just hoping someone will see this, and consider rewording the article)

HTML comment revealed. If you mean Lx, it is in the 2 and 3 dimensional cases; in the one-d case, there is no point to the subscript since there is only one L to keep track of. Please put this kind of comment on the Talk page for the article. GangofOne 20:50, 18 February 2006 (UTC)

linear momentum derivation[edit]

Why isn't linear momentum specified explicitly? Based on the derivation shown, the starting point was obviously ?x, yet it just shows the Hnx = -(h2/2m)*(d2/dd2), without even mentioning that this is derived from the linear momentum operator, ?x = -ihd/dd, why is that?-- 14:34, 18 February 2006 (UTC)

Because it was written by someone else who didn't think of it. That would be a reasonable addition. Please add it. GangofOne 20:50, 18 February 2006 (UTC)

potential energy diagram[edit]

Is this really the best diagram for the article? I mean it doesn't even show the infinite potential zones, it mentions them in the caption instead-- 14:42, 18 February 2006 (UTC)

I mean really, 10 minutes in Windows PS... [11], [12], [13]-- 15:23, 18 February 2006 (UTC)
Hi there. This is a page for questions on science, not comments on science articles. If you'd like to fix something that's not so good in article, you can fix it yourself! Just click the edit tab at the top of any page. You could even upload a better image than the one we have, as long as you make sure you have the right to do so under the GFDL. Anyway, if you edited the article yourself it would actually be much easier to see what you're talking about—small errors are very hard to find in a big article when I don't know where to look, but you've already found them! :) Thanks for your help. -- SCZenz 17:24, 18 February 2006 (UTC)
  • Well, the first 2 are questions, even if the 3rd is really more nitpicking than question-- 18:01, 18 February 2006 (UTC)
Your comments are good, put them on the talk page; here they will probably not be seen by people interested in that article. Or like SCZenz said, just fix the article. Thanks for your contributions. GangofOne 20:50, 18 February 2006 (UTC)

formatting (sidebar)[edit]

You really shouldn't blame me for it. You might want to use a less specific pronoun. Perhaps they, or even better just refer to the article in the 3rd person.  freshgavinG???  15:20, 18 February 2006 (UTC)
fixed ;)-- 15:26, 18 February 2006 (UTC)
And do me a favor and don't use header tags (===header===) for each individual reply. It makes the table of contents at the top much bigger than it has to be, and your question isn't that long. Simply use bold text '''bold text here''' if you want to separate the text with titles.  freshgavinG???  16:12, 18 February 2006 (UTC)
  • They're 3 seperate questions, why shouldn't they have 3 seperate headers? The only reason I even put them as sub-headers is because they all relate to the same article-- 17:14, 18 February 2006 (UTC)

Painless suicide[edit]

User:Ashenai deleted many of the responses here, in such a way that it was impossible to restore normally, so I put them back in a new thread: Wikipedia:Reference_desk/Science#Painless_suicide_2. DirkvdM 10:30, 19 February 2006 (UTC)

Is there any easy, painless way to suicide? How about getting unconscious--is there any easy way to do that? I'm not trying to be stupid--these questions are very serious. --Bowlhover 18:14, 18 February 2006 (UTC)

Consult a doctor. -Quasipalm 18:16, 18 February 2006 (UTC)
This coincidence thing is really starting to scare me. I just finished watching the film MASH. You know, with the title song suicide is painless. And now this question. Please tell me you're from the Netherlands or thereabouts and watched it on rtl7, so there's a perfectly rational explanation and I can sleep again. Anyway, in that film the dentist commits a fake suicide with a 'black pill'. DirkvdM 19:29, 18 February 2006 (UTC) (edited: Ashenai 00:05, 19 February 2006 (UTC))
It is easy to understand painful suicides. These people are in enough emotional pain that physical pain is not a problem. Often, suicidal people cut and burn themselves. A theory is that the physical pain temporarily distracts them from the emotional pain.

--Kainaw (talk) 19:54, 18 February 2006 (UTC)

Have you considered therapy? Or is this for a book or something? Black Carrot 20:20, 18 February 2006 (UTC)

I once started to seriously, intellectually contemplate suicide; how to do it, effectiveness, etc. Once you start dwelling on it, it means that you are really low on serotonin, and going into a deep, black hole. Usually, at the same time, you are drinking a lot. This happens to many intellectuals of northern European descent, and gets bad after 40. Luckily, now, there are some very simple pills for this (which I take). But you have to take the first step and see a doctor about it. I think we saved the life of a friend, by convincing her to go to a doctor. However, there are so many people walking around that are self-medicating (alcohol, drugs), and are too proud to seek medical attention. --Zeizmic 20:39, 18 February 2006 (UTC)

This question is not for a book, nor have I heard the song "suicide is painless". I really do want to die. (Sigh.) It depends on how well tomorrow turns out. I've been having a lot of stress lately, but my stress level tripled today due to a huge argument with a family member and extortion from that family member. Maybe slicing apart a major artery is the best way to die, since it's so easy to do and is not very painful (right?). Anyways, I haven't thought about consulting a doctor or having therapy, since this is a family issue.

My life has been very coincidental these days, too. While I'm struggling to deal with stress, my friend is struggling to deal with sadness--one of his close relatives died yesterday. --Bowlhover 21:38, 18 February 2006 (UTC)

Seriously, don't kill yourself. Try running away instead. If you have nothing to live for, you have nothing to lose, right? Pick a country you've always wanted to see and go there, make a new life for yourself. —Keenan Pepper 21:51, 18 February 2006 (UTC) (edited: Ashenai 00:05, 19 February 2006 (UTC))
I think the response to this reflects very badly on the Reference Desk. I can only recommended some kind of emotional support charity like the Samaritans (charity). Sum0 23:52, 18 February 2006 (UTC)

Please note: I have heavily edited the responses to this question. I sincerely apologize for having edited other people's comments. This was a moral imperative for me. Anyone is welcome to put the responses back; I will not edit them again. But I would humbly plead that you don't.

Bowlhover: please seek professional help. The problem is probably a chemical issue in your brain; things are not as bad as they look. There is help. --Ashenai 00:05, 19 February 2006 (UTC)

Of course, I'm not considering suicide just because of an argument. I've been considering it for a long time, and the argument is only another reason for wanting to do it. I don't have any problems with therapy--it's just that, in my situation, having a therapy is impossible. Also, carbon monoxide and cyanide are good ways to die if I can access them easily, but unfortunately I can't. I need a method that uses things which are easy to obtain. --Bowlhover 00:24, 19 February 2006 (UTC)
I also think we have the moral obligation to assist the individual if the individual wants to, just as long as it isn't frivolous. See Right to die. Why do you want to commit suicide? Elle vécut heureuse à jamais (Be eudaimonic!) 00:26, 19 February 2006 (UTC)
I agree with the Right to die. I also believe that it is impossible to properly diagnose a person over the Internet, especially if the people doing the diagnosing are laymen. This isn't like someone stumbling into an article and writing well-intentioned nonsense. Anti-elitism is all well and good, but let's keep a sense of perspective, here. --Ashenai 00:30, 19 February 2006 (UTC)

Bowlhover, before you decide anything, think of this. You mention your friend's sadness ofer his recent loss. If you commit suicide, what will that do to him? He needs your support at this time - the last thing he would need is for you to die as well. Ashenai is right about internet diagnosis, but I suspect that you live in a nortehrn hemisphere country, and if so, you may well be feeling some of the effects of the lack of sunlight at this time of year, which can affect your brain chemistry and does increase perceived stress considerably (it's called Seasonal affective disorder). Don't be afraid or ashamed of asking for professional help - believe me, as a S.A.D. sufferer myself, it helps a lot. Grutness...wha? 00:33, 19 February 2006 (UTC)

I want to make sure I understand this... You feel morally superior to everyone else so you are tasked with the requirement to censor information available to everyone else? In my opinion, that is simple stupidity. --Kainaw (talk) 00:34, 19 February 2006 (UTC)
Huh? I never censored anything! Grutness...wha? 00:42, 19 February 2006 (UTC)
My reply was separated from the "I'm deleting responses" message earlier. Deleting other's responses is censorship. --Kainaw (talk) 00:47, 19 February 2006 (UTC)
I think you misunderstand. I do not feel morally superior to anyone. I'm not even sure the term "morally superior" actually means anything. I am tasked with the requirement to follow my moral imperatives, just like everyone else. And that is what I have done. --Ashenai 01:12, 19 February 2006 (UTC)

I also agree with the right to die. But I profoundly disagree that it is anybody else's moral obligation to help them do so. If anything, we have a moral obligation to try to dissuade them. Proferring "helpful" suggestions about how to go about suicide in a forum like this is obscene, and could very well be illegal. JackofOz 00:40, 19 February 2006 (UTC)

Bowlhover, please think of all the good reasons to stay with us. The list is far longer than your present problems. This too shall pass. JackofOz 00:40, 19 February 2006 (UTC)

It is not illegal in any way to explain the common methods of suicide. It is also a matter of opinion to consider it obscene. I find censorship obscene. Telling someone who is obviously hurting that you are superior and they are inferior (which is the primary message of censorship) is in no way helpful. Providing answers to all of their questions - even the ones you disagree with - is a way to get communication going and bring a person to talk about their feelings. As it is, this thread has become nothing but a push to tell someone they aren't worthy of answers and their feelings don't matter because they will pass. How pathetic. --Kainaw (talk) 00:46, 19 February 2006 (UTC)
I fully support Ashenai's actions. For the record, it is illegal in Australia to advise people how to commit suicide. I can only suggest that Bowlover seek counselling as soon as possible. Most Yellow Pages contain numbers for urgent counselling and I suggest you give such a service a call. Capitalistroadster 01:20, 19 February 2006 (UTC)
Kainaw, of course it is a matter of opinion whether something is obscene. Just as it is a matter of opinion whether someone's response to a question is censorship. If somebody posted a question saying they were thinking of destroying a building and all of its occupants, and wanting to know the best method, would you just offer a suggestion? I certainly hope not, and I would never call that censorship.
Suicide is a fairly emotional issue, particularly for those of us who've lost loved ones this way (and I speak from bitter experience here). I think it helps to keep in mind that, whatever disagreements we may with others' responses, it is not a case of anybody being "morally superior" to anybody else. JackofOz 01:59, 19 February 2006 (UTC)
Deleting someone's response is, by definition, censorship. That is not a matter of opinion. That is a simple fact. The reason given for the deletion was "moral obligation". That means that the deleter felt his/her morals were superior to mine and it was his/her obligation to undo anything supported by my morals. That is, by definition, moral superiority. There is no room for argument here. It is a very simple case of censorship based on moral superiority. --Kainaw (talk) 03:40, 19 February 2006 (UTC)

I don't understand why people are saying this question should not be answered. Wikipedia is "The Free Encyclopedia", and information should be freely provided, no matter for what purpose. If someone asks how to make a bomb, we tell them to the best of our ability how to make a bomb. If someone asks what's a painless way to commit suicide, we tell them. Of course people will urge that person not to commit suicide, but there's no reason not to tell them how. It's pointless trying to keep general information like this a secret. The answer to the question is yes, there are (physically) painless ways to kill yourself, including cyanide, carbon monoxide, and drug overdose. —Keenan Pepper 03:53, 19 February 2006 (UTC)

I didn't ask a question about how to destroy buildings. Destroying inhabited buildings is illegal, while suiciding is not (at least not where I live). Of course, I strongly support "right to die", and I've supported it even before I thought about suiciding. Not allowing someone to kill himself/herself is as irrational as toturing someone to make them confess. Why can't someone suicide?
If I reveal my age, will everybody treat me differently? I know the answers to this question are going to be very biased, but I'm going to ask anyways. --Bowlhover 03:56, 19 February 2006 (UTC)
Regardless of your age, my answer is the same: you can kill yourself painlessly. I also feel, as I stated originally, that someone who is contemplating suicide is in serious emotional pain. This isn't a case that can be cured with messages like "you shouldn't think about killing yourself" or "things will get better if you give it time". From my personal experience, my worst times have been followed by my best times. But, I will not tell anyone that things will get better. I will not tell them that they don't have the right to kill themselves. I will only answer their questions to my best ability and hope they ask something that will allow me to provide them with constructive help. --Kainaw (talk) 04:08, 19 February 2006 (UTC)
The great thing about suicide is that it's not one of those things you have to do now or you lose your chance. I mean, you can always do it later.Harvey Fierstein
The man, who in a fit of melancholy, kills himself today, would have wished to live had he waited a week.Voltaire
Which is why he shouldn't have waited another week, because doing so would mean another week of pain. Anyways, I know that it is my decision whether I want to suicide or not. I'll wait until tomorrow and see what happens. --Bowlhover 04:48, 19 February 2006 (UTC)
Why wait? What is there to wait for? I know - that isn't what the moral elite want to ask. But, I've been there and that is what needs to be asked. If there is something inside that wants to wait one more day, what does it want to wait for? Is it just the anamlistic yearning to survive or is there actually something there? Only by understanding why part of you wants to die and part of you wants to live can you understand yourself. For me, I found that I was torn up by desire to change everyone around me. I was in such pain that I couldn't do anything. Then, it just hit me - if I got rid of the desire, I could get rid of the pain. Amazingly, it worked. But, I wouldn't have even thought about it if nobody ever asked me why I was sitting around so depressed and not just getting it over with. --Kainaw (talk) 05:05, 19 February 2006 (UTC)
Bowlhover, I think that what Kainaw is trying to say is that if you give yourself a break and think about what's making you feel bad, and open up to people about how you feel (like youre doing here) then you can sort of figure it out, and you'll feel better. Let go of those depressing thoughts. What do you need them for? The trick is then to let yourself feel better. Letting yourself feel better means giving your brain a little rest, and let nature take over. Youre a creature of nature, and if you let yourself listen to what your nature wants to say your spirits will get bettter. For me that means keeping my mind and body busy and healthy. Getting out and walking around can help. Its not about "avoiding" the things that get you down, but treating depressing thoughts for what they are --just thoughts. Thoughts are just thoughts. Your life is much more than that. People are mostly good --thats what makes life worth living (for me anyway). Hope peoples comments and responses to you have been helpful. :) -Ste|vertigo 05:28, 19 February 2006 (UTC)

I'll just mention my basic "sanity check" when I think about suicide: If there is anyone who would be upset, angry, irritated, inconvienced, alarmed, or otherwise emontionally (or even physically) harmed by me killing myself, then it is not right for me to do so. I could only kil myself if I was sure that it would harm no-one else. The reasoning for this is as follows: It is bad to cause unnecessary harm to anyone, myself or anyone else. It is not directly bad to suffer - it's unpleasent, but it may be useful, so it's not a obvious bad thing - so, my suffering should count less than anyone else's - killing myself is only an option if it would not harm anyone else. I don't know if this will be helpful. JesseW, the juggling janitor 09:56, 19 February 2006 (UTC)

Here's my opinion on suicide: if I suicide and leave a note explaining why I did so, I'm sure my relatives/friends will understand me. They should be happy that I got relieved from the emotional pain I experienced. Anyways, I'm 13 years old and wanted to suicide for a long time due to depression. Stress is a relatively new and unwelcome addition to my life. First, homework really made me stressed out. Then, yesterday, my dad wanted me to attend a private school on Sundays from nine-something to two fifteen. I know this doesn't sound like a big deal, but I really need 2 days to rest every week, and there's already enough homework. My dad doesn't care about this--he just threatened to take away my computer, telephone, etc if I refuse to attend the school.
Today, from 10:40 to 12:40, I had math at the school. I had english from 12:50 or so until 14:15. Both classes sucked, and I have a computer class at 17:00. So basically, this Sunday is like a regular school day.
Depression has been with me for a while. There's nothing interesting to do. I don't share most peoples' interests and I'm bored almost every day. --Bowlhover 21:24, 19 February 2006 (UTC)
I have to agree with others in that because we here are not in a position to guage your feelings very well and talk with you in person, that this isn't the best place to talk about your personal problems. Were not really prepared to deal with a crisis situation. That said, I think its good that youre talking about your problems somewhere, and it looks like you needed to get some things out, but didnt quite know who to trust. Anonymity here sometimes provides people with an outlet and thats understandable --we all need to express ourselves. I might add that you seem to compose your thoughts pretty well for a kid. At your age, people in the world start to put their pressures onto you. Its normal, and part of growing up. Your parents (in particular) might be a little bit out of hand with trying to get you to do stuff, but again, thats something we cant read into.
It doesnt seem like your folks abuse or neglect you, so maybe they wouldnt be the wrong people to talk to. Maybe if you told them how depressed you feel about whats going on, they would change direction a little bit and listen to you a bit more clearly. You should be able to find a compromise. Another close relative might be better to talk to if you feel like your being judged too hard by your folks. Just dont keep it "bottled up" too long. What I think about suicide is that all suicides are just people whove let themselves become confused by what they think and feel. Often times the only real "problem" is when people dwelling on their problems too long (called ruminative thinking). When you say "I dont share peoples interests" what do you mean? What interest are available to you or do you feel are being pushed onto you? What are you really interested in? -Ste|vertigo 21:53, 19 February 2006 (UTC)
Take a look at Clinical depression and see if the symptoms match how you feel. --cesarb 21:58, 19 February 2006 (UTC)

I know the reference desk isn't the best place to ask for it, but I desperately need advice from different people. I've told my mom what I feel about the classes, but my dad usually doesn't listen to anybody--he has to have it his way. For things like this, there's usually no chance of dicussion/compromise Oh well, I'll try to talk to my dad about the classes anyways. (I wish my parents were physically abusing me. At least then I would have a good excuse for being dead.)

I spent today's three classes panicking and drawing up a detailed plan for suicide. It probably wouldn't be an exaggeration to say that today is the worst day of my life.

When I said "I don't share most peoples' interests", I meant that I don't like playing with other people, listening to music, drawing, going to the movies, or any other thing that most people my age like. In fact, I don't think I'm really interested in anything. That's why my life is boring.

As for clinical depression, I fit the symptoms. A depressed mood is common for me, and I definitely have a loss in interest or pleasure. I fit 6 out of the 12 symptoms listed after "loss of interest or pleasure". --Bowlhover 04:34, 20 February 2006 (UTC)

Please don't rule out getting help. It can be anonymous. For example, you can email The Samaritans ( like someone suggested. They don't require any identifying information. Superm401 - Talk 08:51, 20 February 2006 (UTC)

While you're reading Wikipedia articles, also read anhedonia. My head just about exploded when someone mentioned that word to me a couple months ago -- it fit me so well.

Don't just talk to your dad about the classes -- see if you can't find a way to talk to him about the depression as well. His answers might seem useless, but if so, that doesn't mean he doesn't care, just that these are hard things to talk about and hard questions to answer.

You said, "I desperately need advice from different people". I'm sure there are people here who would be glad to do that via email as well.

On the "life is boring" front -- do you enjoy editing Wikipedia? Steve Summit (talk) 15:25, 20 February 2006 (UTC)

Tell people you plan to kill yourself. You might think "oh, that's embarassing" or "what about the consequences" but if you are going to kill yourself, what does any of that matter. So tell people: police, teachers, anybody, everybody. Every piece of paper you turn in for homework or a test should have "I'm going to kill myself" on it. What's the worst that could happen? You're gonna kill youself anyway, right? So why not tell people? When they ask for a plan, make sure you have one or they won't believe you. Something that makes sense and doesn't sound like a joke. And be clear you absolutely have no plan or reason to take anyone with you when you leave this world. Don't be scared. Lots of people cry out for help in various ways. Saying "I'm going to kill myself" is so common a way of asking for help that it is often ignored. Moreso in the past than currently. Teachers, especially, are told to take it seriously. What NOT to do: one person put a gun to his head, blew his face off and lived, was hospitalized, months later was released, then successfuly killed himself. 17:16, 20 February 2006 (UTC)

I definitely have anhedonia. Activities that are normally pleasurable, like editing Wikipedia, are no longer that fun. (Editing Wikipedia was never very fun, but it was better than everything else I tried.) Anyways, although I obviously haven't had sexual intercourse yet, "ejaculatory anhedonia" does affect me. Being a person who isn't embarrassed by talking about sex, I'll say that I masturbated last weekend just to cure boredom. There was 2 seconds of pleasure--the rest of the process was not pleasurable at all and even a little painful.
Talking about things in real time, especially with my dad, is my major weak point. I'm usually scared and embarrassed to discuss things like this. I asked for advice here for anonymity reasons, and I'll probably also contact the Samaritans using an email account other than my main one.
Telling my parents, friends, classmates, and/or teachers about my plan to suicide is not a good idea because they will try to prevent me from suiciding. Even if they don't, they will certainly make me talk about my situation. --Bowlhover 04:53, 21 February 2006 (UTC)
Is there any way for me, as a 13-year-old, to suicide painlessly? The main issue here is accessibility--the materials used in the suicide method cannot cost more than about $50, and they have to be easily obtainable. You can bet that if I have the things necessary to kill myself without experiencing any pain, I will definitely do so. So I'm not hesitating on whether I really want to die--I'm just a coward. --Bowlhover 05:18, 21 February 2006 (UTC)

Not really, the human body isn't built like that. Physical pain exists as a warning to the brain to stop doing something which will damage the rest of the body. That's why pain is so difficult to cope with. Emotional pain is no easier, especially as it has the habit of going on for longer: and it's much less clear to know what to do to make it go away, because it is the mind itself that is affected. All the same, it does go away: the only way you're be sure to be unhappy for the rest of your life is to end it now! You mentioned the Samaritans: this is their email address. Physchim62 (talk) 08:13, 21 February 2006 (UTC)

Leaving aside for the moment the problem that you're reluctant to talk to your dad abut this at all ('cos that's a hard problem that I don't have an answer to), and also leaving aside the worry that telling him your plan is a bad idea because he'd just try to talk you out of it, is part of the problem here that if you tell him you're depressed, or that this extra-school-on-Sunday thing is only making things worse, you're afraid he'll just say something like, "Quit whining, every adolescent goes through this sort of thing, I guess I did, but I got over it, what are you complaining about?" Anybody got any suggestions for Bowlhover for ways he could let his parents know this is serious, a way to say (with dignity) "Hey, pay attention to me, I need a little help here", without having to play the suicide card? --Steve Summit (talk) 16:50, 21 February 2006 (UTC)

My dad is not going to say "quit whinning". He's probably going to say "If you don't want to go to the school, get out of the house." or something even more harsh. I don't like real-time discussions in general, because they make me nervous. Having a face-to-face talk with my parents about suicide is going to give me a panic attack.
I've been wondering for some time now: this is Wikipedia, a popular website. What would happen if my parents discover this reference desk? If they read my posts, they'll know immediately that "Bowlhover" is me. And even if they don't, I accidentally revealed my IP address once and deliberately revealed it once. I have no idea whether my dad knows our IP address or not, though. I also have no idea if my dad is going to take my posts seriously, or if he's going to tell me to stop lying/vandalizing. --Bowlhover 21:35, 21 February 2006 (UTC)
Okay, it sounds like talking to your dad is probably out for now. Is there anyone you can overcome your nervousness and talk to? A counselor or favorite teacher at school, or an aunt or uncle or cousin, or neighbor, or anybody? Not necessarily to talk to about suicide -- that might give them a panic attack, too -- but just to talk to about life, the universe, and the pursuit of happiness, and depression, and everything.
I wouldn't worry about your dad tracking you down on Wikipedia by IP address. I know a lot more about Wikipedia than I'm guessing your dad does, and I wouldn't be able to track you down by IP address. More worrisome would be if you and he share the same computer in your house or something like that, such that your Wikipedia login cookies could end up taking him to your talk page if he ever ventured onto Wikipedia. So if that's a potential problem you'll obviously want to make sure to use the "log out" button. Also, of course, if he guessed that you were hanging out on Wikipedia and guessed that "Bowlhover" might be your handle, there's not much you can do about that.
As you've seen, there are people here willing to talk to you over email if you're interested; that's nicely non-real-time. You might be worried about our being able to track you down by your email address, but if you couldn't accept our promises not to, obviously you could get a throwaway hotmail account or something. (And, barring that, your talk page will do fine.) Steve Summit (talk) 00:15, 22 February 2006 (UTC)
If my dad knows my IP address and sees it on this reference desk, who else could have posted it? Once he knows that I'm Bowlhover, he'll look for other postings by Bowlhover, which will lead him here. Also, it is definitely possible to track me down--this really worries me. Once you know my IP address, it's easy to find out who my Internet Service Provider is. If someone somehow manages to convince my ISP to release information about my IP's not going to be pretty.
My dad has his own computer but uses my computer occasionally. I know how to clear up all personal information (history, cookies, saved passwords, etc) from my browser, so that isn't a problem. My dad wouldn't know that I have an account on Wikipedia. Also, "Bowlhover" is a random name.
I have no choice but to talk to my dad about the classes. However, I'm not at all enthusiastic about it. The inability to properly discuss things with other people is my major weak point. My shyness has a lot to do with it. There are many people who I can talk to about life, but I can't talk to anybody (except my friend) about depression/suicide--they'll all report to my parents.
Last but not least, whatever you do, don't try to discourage me from suiciding by telling me how painful the process will be. Suicide can be done painlessly, it's just that most suicide methods are not available to me. If a completely painless death is not possible, is there a suicide method that does not require me to suffer more than one second of pain? It can be severe pain, just as long as it lasts less than a second. --Bowlhover 04:15, 22 February 2006 (UTC)
I don't think you should be so afraid of your dad or other people finding out. If you're seriously thinking about suicide, your life is already pretty bad. How much worse can it get? Change is good. Why not try making a less drastic change before resorting to suicide? —Keenan Pepper 05:11, 22 February 2006 (UTC)

In the very least, if you think your life is worthless, do something constructive but risky. The two thoughts that come off of my head is running cross-country and climbing mountains, but that would be more exhilarating than....death with no point, right? Go out and *do* something, or take up all the extreme sports you can think of. Extreme ironing, perhaps? Elle vécut heureuse à jamais (Be eudaimonic!) 16:14, 22 February 2006 (UTC)

Last evening, I talked to my dad about the classes. He seemed patient, nice, and understanding, and decided that I don't have to go to the English class because it's useless. He wouldn't change his mind about the other two classes, though. Although I did mention that the classes make me stressed out, and that I panic every time I think of them, I didn't say anything about the numerous near-panic attacks at school (my normal school). For example, in one class, I put my head down, my hands onto my chest, and breathed rapidly, while somebody else was reading aloud. The person sitting opposite of me asked what was going on; I told him that I had a panic attack. He told the teacher, the teacher asked if I was alright at the end of class, I said "yes", and it was over.
I have to wait until the weekend to see how a two-hour class from 10:40 to 12:40, and another two-hour class from 17:00 to 19:00, would make me feel. I have no idea right now. My dad said that I can talk about the computer class after a month, if I don't like it. --Bowlhover 13:28, 23 February 2006 (UTC)
Great! Sounds like youre communicating with your dad, and thinking in terms other than just black or white. That can be hard to do when youve let the needle stick in the same groove too long (see record player if you dont understand this reference! :) ). You seem to be smart and articulate. Dads can be excessive about their sons: Sometimes (often, actually) they just think you have to redeem them for everything they did wrong in life! Sometimes they wish they had daughters instead. Its wierd how parents can be. Youre at the age when youre coming to understand your parents imperfections --and their humanity. We dont like to admit our mistakes, and your dad is 99.9999999999999% likely to be no different from anybody else. A lot of times its just an issue of reciprocity --show youre growing up a little and he might open up to you about something that he regrets --an admission of his own imperfection (and humanity)! Thats worth sticking around for. Just because he's not perfect doesnt mean you cant still love your dad --and vice versa! -Ste|vertigo 17:38, 25 February 2006 (UTC)

Google indexing[edit]

How often does the google bot index pages and if it finds a frame page, will it index both of the frames? --Bjwebb (talk) 19:04, 18 February 2006 (UTC)

Google does not advertise the algorithms is uses. To my knowledge, none of the search engines do. From my experience, when I add a page to my company's list of links, it shows up in Google within two days. So, I assume it indexes on a 24-48 hour period. Also, Googling for current events will turn up news hits quickly. But, since there is Google News, it is reasonable to assume they index online newspapers at least hourly. --Kainaw (talk) 19:49, 18 February 2006 (UTC)
If a page with frames is indexed it is most likely a page with a content and a meny frame. Both frames will be indexed, but the content frame will appear more frequently in the results as it's more relevant. If the page containing both frames is linked frequently it might have a greater chance of appearing in the results. Once again, Google is very secretive, this is only my own experience. Obli (Talk) 22:10, 18 February 2006 (UTC)
Another reason not to use frames. They're a major pain on the Internet. DirkvdM 11:11, 19 February 2006 (UTC)

Battery Difference[edit]

Whats the difference between a lithium ion battery and a lithium poly battery?

See Lithium ion battery and Lithium ion polymer battery]. Sum0 23:48, 18 February 2006 (UTC)

Munchausen syndrome by proxy[edit]

Munchausen syndrome by proxy seems to be something which affects parents wrt (their?) children. Does it apply to an adult wrt another adult for whom thay may have some form of responsibility (and thus they try to make themselves look good by harming the other in some way). If not, is there a name for such behaviour - especially if chronic? -- SGBailey 23:11, 18 February 2006 (UTC)

I don't know, but it is beyond doubt that insanity is genetic. Parents get it from their children. :-) JackofOz 00:28, 19 February 2006 (UTC)
The proxy can be and is most often a child, but doesn't have to be, and doesn't get a different name if the proxy is an adult. - Nunh-huh 00:43, 19 February 2006 (UTC)
Some believe Beverley Allitt, a nurse convicted of murdering children in her care, had MSbP. -- Finlay McWalter | Talk 00:58, 19 February 2006 (UTC)

Forces upon the Head[edit]

How much force can a human head sustain for a short period of time? For example, can a head withstand a 1000N force from a flying object in a car crash? --AMorris (talk)(contribs) 23:26, 18 February 2006 (UTC)

A but vague - for example, a force spread across a nice soft sponge will produce a rather different outcome than the same force on the point of a large machette ;) -Benbread 23:59, 18 February 2006 (UTC)

Yes, I think the important thing is the force divided by the area to which it is applied, i.e. pressure. —Keenan Pepper 03:35, 19 February 2006 (UTC)
This can be answered (but I don't know the answer). What is the pounds/square inch that the skull can handle. I know it has thicker and thinner parts. But, that can be taken into account. I would assume it is very small - a few lbs/in2 - in the temple. It must be very strong - at least 200 lbs/in2 on the forehead. Also, age plays a role. Babies have very soft bone (and large gaps, if I remember correctly). Young adults have the hardest skulls. Bones then get brittle with age. I would assume racial differences come into play also. Since race can be determined by skull structure, some races should have thicker bones than others. --Kainaw (talk) 04:14, 19 February 2006 (UTC)
I don't think there is any consistent racial difference in skull thickness, if facial bone structure is any example. See Race#Physical variation in humans. Also, keep in mind that brain contusion can occur, without having a skull fracture. - Cybergoth 05:04, 19 February 2006 (UTC)
Also, I don't think that mainstream Anthropology believes that "race can be determined by skull structure". What exactly is a race anyways? - Cybergoth 02:52, 21 February 2006 (UTC)
The standard for car crashes (at least in the US) is that the head should not be subjected to more than 200 pounds force in an impact with any part of the passenger compartment. --Carnildo 01:26, 21 February 2006 (UTC)
Keep in mind that most humans can do a headstand (well, if they have the balance) without damage to their skull, so that's 100-200 pounds of force across the top of the head. But, a 100 pound rock dropped on the head from a decent height will probably kill you. fair Remember that the force delivered by a moving object is much greater than the weight of the object under the force of gravity alone. Night Gyr 18:45, 24 February 2006 (UTC)

February 19[edit]


Why all the things in the universe keep revolving, spinning, rotating? For example, electrons spin and revolve around nucleus; moons revolove around planets, which revolve around sun, which in turn revolves around the galactic centre.

Orbital spin is a natural result of trying to find a balance between attraction and momentum. The momentum of the orbiting object is just right to keep it from slamming into the attracting object. So, why doesn't everything just slam into one big blob and get it over with? If it did, we wouldn't be here asking why everything orbits something else. --Kainaw (talk) 00:55, 19 February 2006 (UTC)

Thanx Kainaw. I want to learn more about attraction and momentum "in this context".

For large bodies, it is just the simple laws of motion. For subatomic particles, it is logically identical, but the formulas and theory names change. In general, the Universe isn't as wildly complex as people think. Most of it is repetition. You've just hit on one of them: everything tends to be a circular object orbiting another circular object. --Kainaw (talk) 01:35, 19 February 2006 (UTC)
.. and most of these things (why objects are "circular", why they "rotate") can be explained by some kind of "minimum energy" argument. deeptrivia (talk) 01:41, 19 February 2006 (UTC)

what is minimum energy?

In general, it's much easier for a system to lose energy than gain it. Therefore, if you have a whole bunch of possible solutions for a problem, you can often trim it down by looking only at the ones that satisfy some sort of "minimum energy" condition - ie which ones are based on the system keeping only the energy it has, or losing that which it doesn't need. Confusing Manifestation 10:40, 19 February 2006 (UTC)

Drop a marble onto the side of a round mixing bowl (a half sphere is optimum). What are the chances the marble will roll back and forth in a straight line versus roll in a curved semi-circle? There are far more ways for gravity to cause objects to move in curved ways than straight ways. Far more types of spin velocities than zero spin velocity. Zero spin is just one of many spin velocities, why should it be preferred in the near frictionlessness of outter space? Where friction is important, like on Earth, objects lose rotational energy and stop spinning. Just like the marble loses energy due to friction with air and the mixing bowl and ends up in a minimum energy state sitting unmoving at the botton of the mixing bowl. 17:33, 20 February 2006 (UTC)


Can someone explain to me, why do the ears pop when a flight takes off?

Your body has a small pocket of air in the middle ear. This is used to allow the eardrum to float and be useful. If there was too little or too much pressure, sound would be muffled. When air pressure outside the ear changes (which is what happens when you change altitude quickly), your middle ear needs to find a way to change pressure quickly as well. This is done by opening the eustachian tube - which sounds like a pop - and adjusting pressure to the pressure inside the nose, which (under normal circumstances) is the same as the are pressure outside the body. --Kainaw (talk) 01:30, 19 February 2006 (UTC)
This is more a physics question, not chemistry. ? ?i?ff?? 04:41, 19 February 2006 (UTC)
This question is more physical,not chemical? Might this sentence be more correct ?--HydrogenSu 15:03, 23 February 2006 (UTC)
Boyle's law is also encountered in Chem, so if a school does Chem first it seems like a Chem question. --AySz88^-^ 05:13, 19 February 2006 (UTC)

You also get a similar effect by yawning, since the yawning mechnaism also involves the eustachian tubes. In fact, if the ears do not pop to equalise pressure when there is an internal/external imbalance it can cause pain and ringing in the ears. the best way to alleviate this is often to yawn, in the hope that it will unblock any problems in the Eustachian tube. Grutness...wha? 06:35, 19 February 2006 (UTC)

I hear sucking on hard candy, like a mint or jolly rancher, can help too. Black Carrot 01:56, 20 February 2006 (UTC)
And not having a cold - the mucus from the cold will clog up your eustacian tubes, partially blocking them and making the pressure equalisation more difficult.
Also, to expand on the answers provided - commercial airliners are pressurised at the air pressure of about 2000m, which is high enough for people to breathe comfortably but not so high as to rupture the fuselage. When you take off, the pressure inside the cabin drops, and so the pressure behind your ears drums is higher than ambient, causing a 'popping' noise when it's equalised. The same thing happens in reverse when you land - the ambient pressure will increase, and your ears need to equalise again, just in the other direction. — QuantumEleven | (talk) 15:02, 22 February 2006 (UTC)

Getting bots for Battlefield 2 multiplayer[edit]

We are trying get Battlefield 2 multiplayer working with bots. We tried downloading and running this patch but it didn't work. So does anyone kknow how to get bots working? Thanks. 02:28, 19 February 2006 (UTC)

Nevermind, we got it working, thanks to this site:


"Blueberries can turn your eyes to blue if you eat 'em" Sounds stupid, but is this true?

I can't answer that, but I have read of people whose skin turned orange from eating excessive quantities of carrots. I don't imagine that the color of your eyes would change, but the white part might. User:Zoe|(talk) 06:51, 19 February 2006 (UTC)
No, but the Spice can. :) GeeJo (t) (c)  12:54, 19 February 2006 (UTC)
Regarding orange skin, see Carotenemia. - Cybergoth 22:58, 19 February 2006 (UTC)

inorganic problems!?![edit]

Can anyone please explain what on earth is INERT PAIR EFFECT, and which group(s) shows this effect, why and how? Why should one care to learn this thing!?!

reduction and oxidation.[edit]

How do you know whether an element is reduced or oxidised in chemical reaction? To put it better: how can you say whether a reaction is a reduction or an oxidation process and also which element has more tendency to reduce/oxidise than other elements in a given reaction. Please don't explain based on looking at their charges or comparing their reduction potential values! Thank 05:58, 19 February 2006 (UTC)

Hm. I am pretty sure that this can not be explained without consideration of the redox potential. Sadly, our article is not particularly enlighteneing. might help. Kosebamse 07:25, 19 February 2006 (UTC)
Technically, you can't have just a reduction or oxidation reaction, although you can break a redox reaction into two parts - one where the element loses the electrons and one which gains them. If you calculate the oxidation numbers (roughly equivalent to charge) on each of the elements as they appear in the reaction, you can see which direction the number moves for the reaction in one particular direction. The redox potential will then tell you which direction the reaction itself is more likely to move. You can't answer your question without mentioning those concepts, but hopefully that explains what they mean a tiny bit more than just saying "it's because of oxidation numbers and redox potentials". Maybe working through the examples on redox might help your understanding too. Confusing Manifestation 10:46, 19 February 2006 (UTC)


Is there a place where I could get the listings of un-explored areas of the Earth?

I don't know about any list, but I believe the Foja Mountains is the most recent such discovery. Obli (Talk) 11:51, 19 February 2006 (UTC)
Try Google Earth. It does not clearly show some places, and plenty of names are missing. --DLL 23:29, 19 February 2006 (UTC)

Due to imaginging from space, the surface of the earth is known completly to a scale of a meter or so. Knowledge of under the surface of the earth is largly lacking with mostly asumption. Some think the majority of life on Earth consists of bacteria beneath the surface. The most interesting vast expanses yet to be investigated are at the bottom of the oceans. Less vast are hundeds of square miles of equatorial jungle in Africa, South America, but especially north of Australia in mountainous areas. Under the ice in Antartica (both ice on land and over water) is currently yeilding surprises. 17:46, 20 February 2006 (UTC)

How long can it rotate?[edit]

Just curious again: How long can our Earth keep rotating on its own axis? What would happen if suddenly our "green" earth stopped rotating or moving tomorrow? Will it affect normal life? How many species will get extinct and what steps should be taken by us? PS: I am not stupid!!!

  • Well, if the rotation suddenly stopped, everything not tethered down would find itself propelled at a tangent to the earth at a speed up to about 1000 mph (at the equator) in the direction of the pre-sudden-stop rotation. That would kill most everything real fast, I'd think. But there are a lot more things to worry about; someone might want to do a bit of math to figure out what force would need to be applied to the oblate spheroid to make it stop rotating, and what the side-effects of the application of such force would be. --jpgordon∇∆∇∆ 06:23, 19 February 2006 (UTC)
  • It would take a pretty sizable force! As to "can it keep rotating", it's been doing so for a few billion years now, and has slowed down quite a bit in that time. Back in Jurassic times (100 million years or so ago), the length of the day was a couple of hours shorter than now, and in the earth's very early history the spin was as fast as every 6-8 hours. Barring any outside influence (by which I mean the unlikely event of a collision with something extremely large, for example), it would be reasonable to assume that in a few billion years time the Earth will still be revolving, albeit more slowly. At a very rough guess, I'd suspect Earth in 500 million years time would have days of about 30-35 hours. If anything, the slowing process won't be as strong, though, since by then the moon will be in a considerably larger orbit (it's getting further away), and it is a major gravitational cause of the slowdown in rotation.
(Note: these comments are from memory, so their accuracy may not be 100%. if anyone can verify...?) Grutness...wha? 06:47, 19 February 2006 (UTC)
I'm pretty sure the moon would be approaching rather than receding from the Earth, as you'd need an increase in momentum to get to a higher orbit. Tzarius 06:20, 20 February 2006 (UTC)
See Moon#Orbit - it's moving away at about an inch and a half a year. Grutness...wha? 09:36, 20 February 2006 (UTC)
The moon is moving away because it is a planet and not an Earth satellite in terms of gravitational influence. The late Isaac Asimov suggested a distinction between planet-moon systems and double-planet systems based on what he called a tug-of-war (TOW) value that describes whether the presumed satellite is more firmly under the gravitational influence of the presumed planetary primary or the Sun. In the case of the Moon, the Sun "wins" the tug of war, i.e., its gravitational hold on the Moon is greater than that of Earth. The opposite is true for other presumed satellites in the Solar System (with a few exceptions), including the Pluto-Charon system. By this definition, the Earth and Moon form a double-planet system, but Pluto and Charon represent a true primary with a satellite.
Er, okay, that seems rather arbitrary, but the lightbulb did switch on after reading about the Tidal Brake. Thanks Grutness! Tzarius 07:10, 22 February 2006 (UTC)
    • What causes the earth's axis to flip? And does all life die out when it happens? User:Zoe|(talk) 06:53, 19 February 2006 (UTC)
The Earth's axis doesn't "flip". I'm not sure if you mean precession or the flipping of the Earth's magnetic polarity. Neither of these are likely to have caused any species to go extinct, although the magnetic reversal could cause some problems for those animals that use magnetic navigation. StuRat 10:14, 19 February 2006 (UTC)
I'm guessing she's referring to the geomagnetic reversal, which is a "flip" of the magnetic axis. I think that it does have some effect on life on Earth simply because it has an effect on the ionosphere (see the article for a few more details). Confusing Manifestation 10:49, 19 February 2006 (UTC)

Returning to the original question, the Earth will keep rotating as long as it exists, simply because there is nothing that would make it stop. As noted, the rate of rotation is slowing, but that's only due to tidal drag, whose effect is to bring different rotary motions into sync with each other. (Currently, the primary tidal drag is working to synchronize the Earth's rotation (the day) with the Moon's orbital motion around the Earth (the month).)

As noted, stopping the Earth's rotation would require a huge force, and it would also have to be directed in a way that does not occur in nature. But let us imagine that some powerful alien machine actually does this. The alien force acts equally on the different parts of the planet itself and on everything gravitationally bound to it and not in orbit: the atmosphere, the seas and rivers, the people, animals, buildings, and everything else. So everything comes to a gentle stop without being torn apart by stress just from the act of stopping. What then?

Well, the first thing is that the Earth's equatorial bulge (see Earth radius, figure of the Earth) would no longer be supported by centrifugal force. So every place in the tropics would suddenly be higher in elevation than before by at least 5 miles, and every place in the polar regions, lower by a similar amount. So the world's one ocean would divide into two, draining north and south into the polar regions and leaving all the continents joined by a wide strip of land (with lakes or seas where the deepest ocean was) along the equator. Meanwhile most or all of Antarctica, Canada, and Russia would find themselves underwater, as well as other places at similar latitudes.

There would be one particular latitude north and south where the sea level would stay the same, probably somewhere around 40 or 50 degrees; I don't know a quick way to work it out. Even at that latitude there might be massive coastal erosion as the ocean rushed by. Anywhere else, even if an entire country was not left underwater on the one hand or high and dry on the other, coastal cities still would be. My intuition says that these transformations would take something on the order of a few days' time, but I'm really just guessing there.

The conversion of the equatorial bulge into highlands would also put massive stress on the rocks underlying it. Over geological time, with no force supporting it any more, it would tend to collapse and make the Earth spherical; conversely, the polar regions would tend to rise. Which means there would be huge and numerous earthquakes throughout the tropics, and also underwater in the polar regions, perhaps causing tsunamis along on the new coasts. This process would probably begin immediately, but I have no idea how long it would go on; quite possibly for thousands of years. If it slumps a great deal more rapidly than that, then it might ameliorate the sea movements, but then the earthquakes would be even more devastating.

The third major destructive effect would be on the weather. With the Earth no longer rotating, the length of the solar day would now be a full year. So each part of the tropics in turn would now see the Sun shining down continuously for 6 months. Temperatures would climb greatly beyond the normal highs we see today. Conversely, with 6 months of night on the other side, frigid lows would be the rule. With no oceans in the tropics, there would be next to no humidity and I guess the entire band of land would become a desert. Farther away from the equator, the temperature differences would drive intense storms, perhaps permanent ones at some locations.

How many species would die? Most of them. The ones in the best position to survive would be some microorganisms, maybe some hardy plants in mid-latitudes, and any ocean-going creatures that managed to find something to live on. What steps to take? Find a way to negotiate with the aliens to get them not to do this!

--Anonymous, 00:57 UTC, February 20, 2006.

One thing you should realize too, is that the earth is not just a "ball", it would be better to think of it as a giant rotating sphere of water and sand. If a giant rotating sphere of water and sand were to suddenly stop rotating, think of the effect it would have on itself. It would probably momentarily explode only to collapse back in on itself a (relatively) short while later. It's interesting to think of the environmental effects a non-rotating earth would have, but it's not something that could logically happen "suddenly", though you could imagine it happening slowly over a period of a few million years.  freshgavinG???  01:42, 20 February 2006 (UTC)

Rainbow and Earth[edit]

1.What is white light made up of?

All the colors of the rainbow. StuRat 10:18, 19 February 2006 (UTC)
See white, and Colors and Colorimetryb_jonas 12:00, 19 February 2006 (UTC)

2.Why do we first see the lightning and then hear the thunder?

This is due to the difference between the speed of light and the speed of sound. If you go to those two pages, you will find that light travels at a speed of approximately 300,000,000 meters per second, while sound only travels at a typical speed of approximately 340 meters per second. EWS23 | (Leave me a message!) 06:23, 19 February 2006 (UTC)

3.What keeps the earth in it's orbit ?Why does'nt it change it's orbit?

The sun's gravity pulls the Earth towards it, and the Earth's momentum keeps it going in another direction. The force of gravity and the momentum match a particular orbit, and it would take a change in one of the two to change the orbit - either by changing how heavy the sun is, or how heavy the Earth is, or giving the Earth a little push in some direction. Confusing Manifestation 10:52, 19 February 2006 (UTC)

(questions: —Preceding unsigned comment added by (talkcontribs) )

1 - White is plain light - all its visible components blended. Less light seems less white. Any object absorbing some of those components is coloured by the others. There is also diffraction, e.g. by water in the air, that gives rainbows. Try with a gardening hose (personal research).
2 - When you see the lightning, begin to count, and multiply by 300 to have an idea of the distance of the impact in m. (count 3 = 1 km).
3 -Archimedes failed, so we are still waiting for a comet to give that little push. --DLL 23:14, 19 February 2006 (UTC)

Aluminium chloride.[edit]

I know Aluminium chloride is used in lots of organic reactions as a catalyst. But what properties does aluminium chloride has that makes it an effective catalyst, apart from increasing the rate of reaction and being a very strong lewis acid? How does this properties affect the reaction. Please explain. Thank you.

Given the phrasing of the question, I'll answer it close to a high-school level of chemistry. If you want further clarification on any points just ask. With Friedel-Crafts reactions, the positive carbon end of the instantaneous dipole formed by halides isn't electrophilic enough to successfully attack the relatively stable and delocalised negative charge surrounding aromatic rings. When you add a "halogen carrier" such as Aluminium chloride or Iron(III) chloride, it "pulls off" the halide from the molecule you're trying to add, leaving a carbocation. This is electronegative enough to react with the aromatic ring, and displaces a hydrogen from the ring in an electrophilic aromatic substitution reaction. GeeJo (t) (c)  15:53, 19 February 2006 (UTC)


What is the m4a file format and is there a way to make Windows Media Player understand the files instead of RealPlayer? I am not a fan of Real.

I believe m4a is apple's slightly more effective, unprotected (no DRM) version of mp3/wma, perhaps you should try itunes... Obli (Talk) 12:05, 19 February 2006 (UTC)
Windows media player in no way can understand m4a, and iTunes cannot understand wma. Its not gonna happen. But I am pretty sure you can convert wma to real. [14] [15] I haven't downloaded them and do not guarantee them free of spyware, adware and viruses.
.m4a and .m4p are containers for AAC, unprotected and protected respectively. AAC is a standard, but doesn't appear to have widespread support (ignoring iTunes and the PSP. Tzarius 06:34, 20 February 2006 (UTC)
All you need to do is set a different file association. Winamp can read AAC files, so if you download and install that, you can use it instead of realplayer. Night Gyr 18:48, 24 February 2006 (UTC)

So a parrot and a lemur walk into a bar...[edit]

Every now and then, here in the States on the local news, there will be a story, usually light filler, about two animals of different species hooking up and becoming best friends. Like a dog that is raising Cougar kittens for whatever reason. Or that snake that made a bond with a hamster rather than eating it. We see it with humans all the time, but it almost never happens with our animal brethren, so it is a matter of infinite fascination when this stuff comes to light.

So, my question is, what is this called, when two animals of different species that would otherwise not associate with each other inexplicably become, well, friends? Is there actual scientific study into this? What is such study called? Has any such study found out why or how they do this? Or is it just an asounding anomoly? --Jeffrey O. Gustafson - Shazaam! - <*> 06:57, 19 February 2006 (UTC)

This isn't an answer, but did you ever hear about the Vermont moose who, in 1986 "fell in love" with a farmer's dairy cow? He never tried anything with Jessica, though. Newspaper said he stayed with her all season. Leah
It was stories like that which convinced me I'm not human. They're called "human interest stories", see, and they never interest me at all. Grutness...wha? 11:23, 19 February 2006 (UTC)
I'm not sure why you think different animals "would otherwise not associate with each other". Why shouldn't they? Lots of animals get together for their mutual benefit, like cattle and cattle egrets, and ants and aphids, not to speak of humans and dogs, man's best friend apparently. --Shantavira 15:36, 19 February 2006 (UTC)
Symbiosis? --Sam Pointon 19:41, 19 February 2006 (UTC)
Yes, that's symbiosis. Other reasons include where a baby treats the first animal it sees as it's mother. The reverse can also happen, especially if the mother just lost it's own young. I once had a cat who had lost her kittens and "adopted" a litter of socks, which she carried around with her from place to place. There is also the story of the bird who caught worms for her adopted kitten. Cross-species "romantic" liaisons have also been reported, but this is almost always one-sided, as in the small dog attempting to mate with a lioness. Young of different species will "play" together, too. This isn't always as innocent as it appears, however. A young predator may actually be practicing it's hunting skills, but just lacks the knowledge of how to kill the prey. Also, during a fire or other natural disaster, you will see predator and prey flee together. The predators are too busy trying to save their own lives to hunt, and the potential prey know this. StuRat 19:55, 19 February 2006 (UTC)
"Other reasons include where a baby treats the first animal it sees as it's mother." - this is called imprinting Raul654 20:05, 19 February 2006 (UTC)
Thanks, that's the term I was looking for. StuRat 20:16, 19 February 2006 (UTC)
I agree with Grutness :) — Ilyanep (Talk) 20:12, 19 February 2006 (UTC)

In the case of the snake and the hamster, it looks like the hamster was just too big for the snake to swallow, so it didn't even try. This is an interesting definition of a friend: "someone who finds you too large to swallow whole, so allows you to live". StuRat 19:32, 19 February 2006 (UTC)

Two cases I know of personally. (1) We once got from my wife's sister two rodents, a gerbil and a chinese hamster, that had been kept in the same cage together since both were rejected by their mothers. They wer both the runts of their respective litters. We placed their all-glass cage next to the one we already had two 2-year-old female rats in. The hamster and gerbil were continuous nest-builders. They would each build their own nest, live in it far a couple of days, and then rebuild it alll over. Before this time, we had never seen the rats build a nest. Within about three weeks, the rats were building a nest as well; but they shared theirs. My wife's psychology professor refered to what had happened to the rats as "cross-specific modelling". She did not seem to notice the bonding of the hamster and gerbil. (2) On a trip to the Valles Caldera in New Mexico, just west of Los Alamos, were talked to one of the Wildlife scientists, who had just photographically recorded a similar example of cross-specific behavior. A mother elk (wapiti) and her calf were grazing near a barbed wire fence. On the other side of the fence were two mares (female horses). A small pack of wolves crept towar the two elk. The mother elk brought the calf over to the fence, and the mares came to the other side, and hung their heads over the calf to shield it. The mother elk then chased after the wolves, supposedly giving them a few good kicks (no photos of kicks). She then returned to her calf and all four animals resumed grazing.-- 20:23, 19 February 2006 (UTC)

A lesser version of cooperation is where one prey animal sounds an alarm when it sees a predator, originally meant to warn others of it's own species. However, other species learn the warning call, and soon also respond, by heading to their burrows, etc., when they hear the warning call. StuRat 20:37, 19 February 2006 (UTC)
See there Konrad Lorenz and his imprinted geese. I used to love his books. --DLL 23:02, 19 February 2006 (UTC)

I took into consideration symbiosis, thus my qualification that the animals "would otherwise not associate with each other". Such relationships don't follow what clasifies as symbiosis, because neither organism is positively effected, nor negatively effected. The snake and hamster deal is a little obvious, yes, but we all have heard of many other weird couplings that defy classification. Does no such classification exist, or does someone need to create one (0 0 Symbiosis?)? --Jeffrey O. Gustafson - Shazaam! - <*> 04:37, 20 February 2006 (UTC)

Just like humans tend to have an anthropomorphic glance of animals, many animals have a zoopomorphic attitude about other animals. This is why your dog treats you as the alpha male of its pack, if you have him trained. This is why a baby eagle can think a human hand with a glove over it is its mother. This is probably why say, a moose would fall in love with a cow, the moose thinks the cow is another moose.

Anti competitive practise by Microsoft and Google[edit]

We have heard/read that bundling of software- especially Internet Explorer with windows is unfair for competitors of firms that do that. But why is Microsoft Office not considered as a bundle? If those software were sold seperately, Microsoft's share would be far less than what it is today. This bundling would have killed hundreds of start-ups (and the effect far more than IE-Windows bundle) but still no complaint of any such on Microsoft Office. Shouldn't Microsoft be forced to bring a'la carte pricing similar to law enforcing cable companies to sell channels individually? Whats worse, Google is also coming with something called Google Pack. If Microsoft's Office destroyed competition in PC, Google promises to do that to Internet related software. Should legal action be taken against Microsoft and Google?

I don't think I can give a satisfactory answer here, but I assume that since it's part of a larger Suite, Office is regarded as its own large product, even though you can get the components separately. Especially, since the products are related to each other (one can argue that IE or WMP are unrelated to Windows per se). — Ilyanep (Talk) 20:14, 19 February 2006 (UTC)

micro organisms[edit]

when micro organims and fungal spores are added to a liquid medium of residue of grountnutcake curd jaggary etc. and water and allowed to ferment for a few days ,will the micro organisms and fungal spores die?

Micro organisms will grow first - that's what fermentation means. When there is not enough food or water, most will decide to take a little nap, waiting for better condition. Some may die but it is hard to imagine how long it takes and how much is able to revive. --DLL 22:56, 19 February 2006 (UTC)

Painless suicide 2[edit]

User:Ashenai edited out several postst in a previous thread; Wikipedia:Reference_desk/Science#Painless_suicide. When I encountered this it was beyond repair, so the only solution I could think of to revert this vandalism was to post this again. So here it is.

Is there any easy, painless way to suicide? How about getting unconscious--is there any easy way to do that? I'm not trying to be stupid--these questions are very serious. --Bowlhover 18:14, 18 February 2006 (UTC)

Consult a doctor. -Quasipalm 18:16, 18 February 2006 (UTC)
Well there's always cyanide.--Bjwebb (talk) 19:05, 18 February 2006 (UTC)
This coincidence thing is really starting to scare me. I just finished watching the film MASH. You know, with the title song suicide is painless. And now this question. Please tell me you're from the Netherlands or thereabouts and watched it on rtl7, so there's a perfectly rational explanation and I can sleep again. Anyway, in that film the dentist commits a fake suicide with a 'black pill'. But somewhat more seriously, I've never understood why people kill themselves in such painfull ways as shooting a bullet through the brain or even jumping in front of a train or down a cliff. Such people are so stupid they deserve to die, so I suppose there's some justice in that. A much more logical way would be to take an overdose of something pleasant like heroin. The only risk is that you'll like it so much that you decide you no longer want to die. And you'll have to find it first, meaning you might have to contact some shady characters. But they'll want your money more than anything else, so there should be little risk (provided you don't tell them you're going to kill yourself because as long as they think you'll be coming back they want you safe). Oh, and by the way, since you're going to die anyway, you might as well go with a bang, like shooting the local maffia guy if you have one. Make damn sure you got an overdose, though, because else you might still die, but in a somewhat more painful way. This means you'd have to get a gun too, though, making the whole thing a bit complicated (unless you're from the US or Costa Rica, that is). Or you could just get two overdoses - one for you and one for him. And then bump into him or something. I'll stop now before I start getting too creative. :) DirkvdM 19:29, 18 February 2006 (UTC)
I like the idea of taking out some evil bastard with you, perhaps a suicide mission to infiltrate al-Queda and kill Osama bin Laden ? I think many intentionally choose painful suicides to punish themselves and atone for their own misdeeds. The Japanese hara-kiri, for example, seems designed to punish the person for their failure, as well as cause death. StuRat 23:00, 18 February 2006 (UTC)
You'd be a suicide bomber? Tzarius 23:17, 18 February 2006 (UTC)
Yea, but (unlike them) I would only kill al-Queda members, not random innocent civilians. StuRat 10:58, 19 February 2006 (UTC)
How horribly complicated. You'd first have to find out in which country he is, then find him there and then find a way to get close enough with some means to kill him. Why not take ou the local bad guy? However, it would present one with a travelling opportunity, as suggested elsewhere. :) DirkvdM 11:19, 19 February 2006 (UTC)
Dirk, that was almost as good as one of my rants. Just one thing, do you see any inconsistency between going along to Rainbow Gatherings and saying things like "Such people are so stupid they deserve to die"?  :-) JackofOz 21:21, 18 February 2006 (UTC)
I meant that in an evolutionary sense, but even that would have to be taken with the grain of salt that it was intended with. A smiley might have been a good idea. DirkvdM 11:07, 19 February 2006 (UTC)
It is easy to understand painful suicides. These people are in enough emotional pain that physical pain is not a problem. Often, suicidal people cut and burn themselves. A theory is that the physical pain temporarily distracts them from the emotional pain.
As for a painless suicide - carbon monoxide. Blood cells will carry carbon monoxide to the brain instead of oxygen. The brain cells (with no pain receptors) will start to fail. You fall asleep and eventually the brain fails to control the heart all together. --Kainaw (talk) 19:54, 18 February 2006 (UTC)

Have you considered therapy? Or is this for a book or something? Black Carrot 20:20, 18 February 2006 (UTC)

I once started to seriously, intellectually contemplate suicide; how to do it, effectiveness, etc. Once you start dwelling on it, it means that you are really low on serotonin, and going into a deep, black hole. Usually, at the same time, you are drinking a lot. This happens to many intellectuals of northern European descent, and gets bad after 40. Luckily, now, there are some very simple pills for this (which I take). But you have to take the first step and see a doctor about it. I think we saved the life of a friend, by convincing her to go to a doctor. However, there are so many people walking around that are self-medicating (alcohol, drugs), and are too proud to seek medical attention. --Zeizmic 20:39, 18 February 2006 (UTC)

This question is not for a book, nor have I heard the song "suicide is painless". I really do want to die. (Sigh.) It depends on how well tomorrow turns out. I've been having a lot of stress lately, but my stress level tripled today due to a huge argument with a family member and extortion from that family member. Maybe slicing apart a major artery is the best way to die, since it's so easy to do and is not very painful (right?). Anyways, I haven't thought about consulting a doctor or having therapy, since this is a family issue.

My life has been very coincidental these days, too. While I'm struggling to deal with stress, my friend is struggling to deal with sadness--one of his close relatives died yesterday. --Bowlhover 21:38, 18 February 2006 (UTC)

Someone already said carbon monoxide and cyanide, which were the two ways I was going to say. But seriously, don't kill yourself. Try running away instead. If you have nothing to live for, you have nothing to lose, right? Pick a country you've always wanted to see and go there, make a new life for yourself. —Keenan Pepper 21:51, 18 February 2006 (UTC)
I don't think cyanide is a particularly pleasant way to die. For one thing, it's extremely bitter, and those who take it are often found with a puckered face. CO could be painless, if isolated from the exhaust fumes from which it usually comes, and if you're already asleep when exposed. Being exposed while awake can cause severe headaches and being exposed to exhaust fumes causes choking. StuRat 22:47, 18 February 2006 (UTC)
I think the response to this reflects very badly on the Reference Desk. I can only recommended some kind of emotional support charity like the Samaritans (charity). Sum0 23:52, 18 February 2006 (UTC)

So far the part of the thread that was deleted.

Some good responses have been given in the original thread, like completely changing your life. If you're going to do something drastic like that you might as well try something less lethal first. Thus, having contemplated suicide can be quite liberating, like starting life all over again. I'm not in favour of professional therapy. The best help can be gotten from family and friends. Only if that fails does a therapist might make sense. We at the Ref Desk can be friends too, although communication is a bit impersonal. Still, we can try. The change in life that was suggested was to travel or move to another beautiful country. One would need money for that, though. You could also move to another city in your own country or, if you live in a city move to the coutryside (or vice versa). Or find something that you might get completely absorbed by. Maybe learn a trade. Or express your feelings in art. A classic method is to join the foreign legion or some religious cult. I certainly wouldn't recommend those, but maybe a variation on that theme? Maybe become a freemason? I don't know, any better ideas? DirkvdM 11:07, 19 February 2006 (UTC)

Other than a family spat, we don't know why you feel this way. At one time I wanted more than anything to just be dead. It didn't work. I will always know that an angel intervened. Dead is forever. I know it seems like you'll never be happy again, but don't do this now. If you don't do this you will begin to feel better.-- Leah

I certainly agree that you should wait. Like Leah said, you can decide to die any time, but once dead, you never get the chance to decide again. Also, we would all miss your contributions here. StuRat 19:12, 19 February 2006 (UTC)

One of the more authoritative sources is the faq]. Your choices are yours, but like others I would suggest therapy or contacting something like the Samaritans. moink 22:22, 19 February 2006 (UTC)


how can we hack email ids?

hacking as in getting to know the password

I believe that is usually done through social hacking or by trying obvious passwords. So make shure your passwords aren't obvious. At least the ones that matter. I use one simple password (simple to me) for a lot of less important stuff to avoid having to remember too many. DirkvdM 12:53, 19 February 2006 (UTC)
There are three commmon methods: 1) Hack the server, get the password file, hack the password file. 2) Put spyware on a person's computer and spy on them typing their password. 3) Ask the person for their password - many people are stupid enough to give it to you if you just ask. --Kainaw (talk) 18:17, 19 February 2006 (UTC)
Another common scam is spoofing or phishing, where someone will send you an email that appears to be from a legitimate organization that you use and trust, such as eBay or PayPal. When you go to the website (that looks like the real thing) and enter your information into that spoof site, the scammers have your user name and password. As for email accounts, this can occur if someone does a spoofing scam that appears to be a (for example) Yahoo! log-in page of some sort. EWS23 | (Leave me a message!) 23:20, 19 February 2006 (UTC)

Education in US[edit]

What it takes to be successful in SAT? How should I prepare? What are the subjects? I'm a JC1 (grade 11) student. When can I give the test?

As an American, I'd just like to point out that the title of this question is an oxymoron, when you get to a university in 2 years, you'll know why-- 23:33, 19 February 2006 (UTC)

See this site for a free practice test: [16] StuRat 19:03, 19 February 2006 (UTC)

The SAT has three sections: math, verbal, and essay. The math and verbal sections are collections of tricks. You already know the answers to all of the questions; they just try to trip you up. Buy a practice book or two, read about the tricks, take a couple of practice exams, and see what gives you a hard time. For those sections, that's all you need. I can't help you with the essay section; I took the SAT before they introduced it. --Smack (talk) 06:30, 20 February 2006 (UTC)

Beats Per Minute[edit]

Is there a good software program out there that, given an mp3 file (say) will help you calculate the number of beats per minute? I want something that will find the BPM in each bar or so, even if the song itself has subtle changes in speed. I don't mind if I have to tap the beat along with the spacebar or something, but I do want to finish the program with an output something along the lines of

Bar 1: 180.0 BPM
Bar 2: 180.5 BPM
Bar 3: 179.8 BPM

and so forth. Confusing Manifestation 12:38, 19 February 2006 (UTC)

Hmm I'm interested in that as well...since a lot of music library programs (such as iTunes and WMP) have a (useless) BPM field (I assume it's an ID3 standard tag or something). It'd be somewhat of a fun timekiller to do that :P — Ilyanep (Talk) 20:05, 19 February 2006 (UTC)
I'm actually interested because I'm trying to write a Dance With Intensity file with a program called xstep, that has a similar feature, but it basically assumes that the BPM is constant for most of the song so it just lets you tap the Enter key for 2 bars and works out the BPM from that. Unfortunately, if the song doesn't have an electronic back-beat and it wasn't played while keeping an eye on a metronome, that doesn't help when consecutive bars vary like I described above. Confusing Manifestation 11:53, 20 February 2006 (UTC)

Audacity has a beat finding algorithm. I've never used it, but if the default one doesn't work, you should be able to find a plugin that does. You'll have to convert the mp3 to a format such as WAV that Audacity can work with. - Taxman Talk 17:50, 20 February 2006 (UTC)

Winamp's built in visualizer has a beat-finding algorithm with an output you can read that it uses to pace the visualizations to match the music. You can just play the songs and read off the number. Night Gyr 18:54, 24 February 2006 (UTC)

cone angle checking method[edit]

i would like to know the methods for checking the cone angle of a blind hole. please help me in this regard. i would like to know the methods to check with gauges. we can very well check in a countour or by cutting and checking in a profile projector. please let me know if you have any other methods. thank you.

with regards,


Banana Oil[edit]

I searched over the internet, but couldn't find it. Who was the inventor of Banana Oil or, scientific: pentylacetate / pentylethanoate / amylacetate ? (Or the first who synthesized it by esterification of 3-methyl-1-butanol and acetic acid) effeietsanders 14:02, 19 February 2006 (UTC)


Firefox asked me to enter a new username, and I've accidentaly changed the default user and lost all my bookmarks. How can I get the old default back? 14:20, 19 February 2006 (UTC)

Generally this happens because Firefox crashes and leaves your old profile locked. Assuming you're on Windows 2000/XP, here's how you can most likely resolve this:
  • Press Ctrl-Alt-Delete and bring up the Task Manager. Select the Processes tab, and terminate any running copies of "firefox.exe".
  • Press Start->Run, and type the following into the box:
    "C:\Program Files\Mozilla Firefox\firefox.exe" -profilemanager
  • A box should come up offering a list of profiles to choose from. You should now be able to open the original profile and have all your bookmarks and settings back.
Hope this helps! —David Wahler (talk) 14:53, 19 February 2006 (UTC)
Yes, it worked, thanks a lot! 15:00, 19 February 2006 (UTC)

electro magnets in a security door system[edit]

how do electromagnets work in a security door system. what is their purpose and how do they work. what do they do in the circuit

See our article on magnetic lock. This should answer your questions. --Shantavira 17:13, 19 February 2006 (UTC)
Other than the magnetic lock use, an electromagnet can hold a security door open until there is an emergency. Then, the electricity is stopped and the door shuts. --Kainaw (talk) 18:14, 19 February 2006 (UTC)
The purpose of the electromagnetic door lock in a lecture theatre I know is to allow the door to be unlocked remotely (which is easier to do with an electromagnetic lock versus a mechanical lock I guess) by a computer, so someone doesn't have to go around unlocking doors all morning. I don't know if the front and back door locking circuits are wired in series, but if they are then one command, say unlock, would unlock both doors simultaneously.--Commander Keane 21:43, 19 February 2006 (UTC)

I can think of a bunch of different ways they're used.

  • Probably the most common is a normally-locked door that can be unlocked by energizing an electromagnet. Typically the electromagnet pulls back a piece of metal in the strike plate that the latch normally presses against. (This is probably the type that our nonexistent electric strike article would refer to.) The electromagnet might be operated by
    • a remote pushbutton, such as the ones that allow upstairs apartment dwellers to "buzz in" their visitors at the front door
    • a keypad or card-entry device or other form of Electronic lock.
  • A magnetic lock is a powerful electromagnet that holds a door closed when it is energized. If there is a power failure, the door would become unlocked.
  • A holdback is a device that holds a door open but that can release it to close under certain circumstances. For example, in many public buildings, there are magnetic holdbacks so that doors in corridors can be held open. But in a fire alarm condition, power to the electromagnets is automatically shut off, so that the doors close and limit the spread of fire. During a power failure, the doors also close, so this system is fail safe. (I have also seen nonelectric fire door holdbacks that incorporate a fusible metal link which melts and releases the door during a fire.) Steve Summit (talk) 15:52, 20 February 2006 (UTC)

USB Question[edit]

I'm thinking of building a new computer and I have one quick question. The mother board I am looking at has 4 onboard USB 2.0 ports (as opposed to its 6 rear panel USB 2.0s). My question is, how do I connect the 4 ports (which I assume have pins on the mobo) to the front side ports that I will have in my case? What cables do I need? Will they come with my case? Where can I buy them if they don't? Etc. This isn't the first time I have a built a PC but it is the first time I have gone out and bought the parts specificaly for the build (before I just mixed and matched or used what was lying around). BrokenSegue 18:05, 19 February 2006 (UTC)

Cases that have front usb connectors come with cables that plug into the motherboard. If your case does not have front usb connectors, it will not have the cables (since there is nothing for them to connect to). --Kainaw (talk) 18:12, 19 February 2006 (UTC)
alright thanks BrokenSegue 18:26, 19 February 2006 (UTC)

Here's a Google search that led me to a lot of information about this -- the pinouts on the motherboard are not necessarily the same from manufacturer to manufacturer. I liked this site particularly. --jpgordon∇∆∇∆ 18:38, 19 February 2006 (UTC)

Yes, that was useful. Thanks. BrokenSegue 00:56, 20 February 2006 (UTC)

operating system and kernel[edit]

what is difference between operating system and kernel?and would like to know more about kernel?

The kernel is the part of the system software that does resource allocation and tracking, enforces security and permissions, and does direct interaction with physical devices using the device drivers. The definition of an operating system is a bit blurry. The OS includes the kernel, as well as many other programs. Beyond that, there's not a whole lot of agreement as to where the OS ends and user-level programs begin. Most people include the shell, the GUI, and system utilities (like data backup) as part of the OS. Others think that when you buy the OS in the store, everything that comes on that CD (such as windows media player) is part of the OS. Raul654 19:37, 19 February 2006 (UTC)

It's a fuzzy question, but that's because the definitions are fuzzy. According to some people, the operating system is the kernel, namely, the one, privileged program that runs (usually in the processor's "system mode") and supervises the behavior of all the user-mode or application programs. Services typically performed by the kernel include: process scheduling, I/O, filesystem(s), date/time, and networking. Pretty often, though, the term "operating system" is used to encompass not just the kernel per se, but also those applications which are so closely associated with the system that it's effectively impossible to use it without them. Under Unix and Unix-like systems, those "part of the OS" applications would include the shells, the system daemons, and the standard toolkit programs such as cat, rm, sed, grep, etc. Under Windows, I've heard that MS Internet Explorer (though it's nominally an app) is variously integrated with and vital to the functioning of the rest of the system. --Steve Summit (talk) 18:36, 20 February 2006 (UTC)

I've heard that attempting to delete Windows Explorer will result in a spatial anomaly, causing the universe to collapse.[citation needed] --Optichan 15:54, 22 February 2006 (UTC)

electronic marketplace[edit]

What is disk technology and how is it used in importance with the electronic marketplace? -- 23:54, 19 February 2006 (UTC)

You could do worse than to start with Disk storage. You could also do your own homework. --George 01:03, 20 February 2006 (UTC)
Hmm, what class would ask such a question? o.o --AySz88^-^ 22:23, 20 February 2006 (UTC)
I don't know, there's a lot of technology associated with disks. I'm sure that disk brakes and intervertebral disks are important in the "electronic marketplace". Maybe even accretion disks. =P —Keenan Pepper 03:13, 20 February 2006 (UTC)

February 20[edit]

Forensic pathology[edit]

Any forensic pathologists here? I was reading the article race, and it cites anthropology books to make the claim that, other than a slight difference in skin color, there are no physicial racial traits. So, how do forensic pathologists identify a person's race if the anthropologists claim that there is absolutely no difference between the bones of one race or another? --Kainaw (talk) 03:24, 20 February 2006 (UTC)

That's definitely untrue. There are many physical differences, such as skull shape, that can be used to identify races. StuRat 04:29, 20 February 2006 (UTC)
I think the cause for this confusion is that the taxonomic classification 'race' applies to mankind as a whole. So there is only one human race, homo sapiens sapiens. That does not mean one cannot make a further distinctions, let's call them ethnicities (I don't know if that is technically the correct term). People have evolved in different parts of the world and acquired different traits one could distinguish between. As ethnicities mix, in time the distinctions will become less meaningful and all one will be able to say in the end is that a certain person has a certain skin colour and nose shape and hair, without being able to say that that combination is part of some ethnicity (or race). The whole 'racial' distinction thing is based on pretty shaky grounds. Take East Africans. They're black, but they have straight noses (not broad like West Africans), rather like Europeans. But they're classified as Semites, which puts them in league with the Arabs and Jews, who have different nose shapes yet. The biggest variation is between individuals. It's easier to distinguish between two individuals than between ethnicities. DirkvdM 09:33, 20 February 2006 (UTC)
We don't need to invent a term for this Dirk we have one: race. Rmhermen 18:06, 20 February 2006 (UTC)
The word ethnicity makes me giggle. Especially when someone pronounces it ethnithity. Oh, and ethnarch is the best word ever. —Keenan Pepper 18:10, 20 February 2006 (UTC)
I agree with DurkvdM, that the term race is misleading. In the anthropological and biological sense, there is only one 'race' of humans. There is more genetic variation between individuals than between ethnic groups. Racialists may claim otherwise - see also J. Phillipe Rushton. - Cybergoth 03:09, 21 February 2006 (UTC)
This is what I am reading - please correct me if I am wrong:
The term race has multiple meanings, so instead of discussing physical differences between, say, Asians and Nordic people, we will just say that everyone is part of the human race and ignore the whole topic. Then, if you allow the use of the word race to apply to Asian and Nordic people as an identifier, anthropologists claim that it is not possible to tell them apart from physical identifiers. So, every person that has been identified by forensic pathologists using physicial identifiers to narrow down the race (ie: Asian, Nordic, African...) of the person was basing their science on a falsehood and therefore did not correctly identify the person. Right? --Kainaw (talk) 14:29, 21 February 2006 (UTC)
I agree with your first 2 sentences. The last sentence, I am not sure and this goes back to the original question. A forensic scientist, forensic pathologist, or physical anthropologist would be best to answer that question. I don't know how they would identify a person's 'race', say, from skeletal remains, and how accurate that identification would be. - Cybergoth 17:47, 21 February 2006 (UTC)
This article (U.K.) says that you can tell Caucasian, Negro and Mongoloid skeletons apart about 80% of the time, mainly from the skull, and that's all. This article (U.S.A.) says that even these racial categories are outmoded, but at the end explains why they are still used in forensic anthropology. --Heron 21:00, 21 February 2006 (UTC)

The idea that race (or whatever other weird name you want to call it) doesn't exist is just wishful thinking on the part of some overly PC liberals. Beyond differences in skin color there is also hair color, hair texture, eye color, skull shape, and differences in disease susceptibility such as Tay-Sachs disease and sickle-cell anemia. StuRat 07:48, 24 February 2006 (UTC)

Another USB question[edit]

I have a PDA that synchronizes with my computer via a USB cable. It also trickle-charges its batteries through the same cable. However, this trickle-charing degrades battery capacity, so I can't really leave it plugged in all the time. Is there a way I can disable the USB port's power output? --Smack (talk) 06:19, 20 February 2006 (UTC)

I think the power supply is an integral part of the USB interface, so you can't disable it. But why do you say trickle-charging degrades battery capacity? I know overcharging can damage batteries, but your PDA should have circuitry to prevent that. What kind of batteries are they anyway? —Keenan Pepper 18:15, 20 February 2006 (UTC)
If the batteries are nickel-cadmium, then you may be running into the memory effect. --Carnildo 21:11, 20 February 2006 (UTC)

well you could cut open a USB cable and cut the red wire. The device may not connect with such a cable though (some devices use the power wire on the USB port to detect plugin. Plugwash 03:28, 24 February 2006 (UTC)

I think it is a memory effect. I charged it with the AC adapter when I first pulled it out of the box, then ran it for months on trickle charging alone, and the battery indicator never budged from full. Then summer vacation hit, and I stopped using the device for three months or so. When I tried to turn it back on, it was completely dead. Tech support had me try the AC adapter again, and it's been working fine ever since. --Smack (talk) 05:02, 24 February 2006 (UTC)

Behavior of gas in a laser tunnel.[edit]


I have this idea for a project that I want to try and get funding for:

I am wondering about the behaviour of the air we breath in an annular or ring laser tunnel.

Laser type: visible, green single mode.

Laser power: seventy to one hundred watts per laser.

Suppliers: Coherent or Laser Systems Europe.

Laser array: one thousand lasers in a collimated array to provide seventy thousand WATTS of visible laser energy in the green spectrum in a laser tunnel.

Laser tunnel: seventy thousand watts in a four inch (outside diameter) ring (three 14/16 inches inside diameter).

Laser tunnel length: two hundred feet.

Chamber conditions: vacume with no humans present in inmediate area of laser array.

Location: subsurface.


Since the laser tunnel is very high intensity will it serve as a pump?

In other words when I release regular air at one end of the tunnel will the inherent reflectivity of the laser tunnel serve as a tube transport for the ultra hot plasma that the normal air will become when exposed to seventy thousand watts of laser energy?

Will any of the super hot plasma reach the other end if the gas inside the tunnel is pushed by a second laser focused on the super hot gas inside the laser tunnel?

Since I notice that vaporized air or steam increases in reflectivity index as compared to regular breathable air at room temp.

Please forgive me for asking this question here since I tried other sites with science forums but users there assumed that I was of low I.Q. with questions like:

"Do you know thats a lot of power?"

"What are you using it for?"

"Do you know thats going to cost a lot of money?"

"Do you know that you are going to need lots of generators to run the lasers?"

Well I hope that some one that knows lasers or can point me to a place where I can find reflectivity indexes for breathable air and ultra high laser power tunnels reads this and helps me out?

Thank you.

R. E. Burrows.

  • reflective indices of for example glass and water are measured compared to air, so air doesn't really have a reflective index (unless you want to use 1). If someone suggested this experiment to me, the first thing I would ask would be "why would the air behave any different than usual?". - Mgm|(talk) 08:23, 20 February 2006 (UTC)
  • Will it serve as a pump? No, not if it's a vacuum. There's nothing to pump. A laser will only pump a medium. If there's air in there, it will only pump it if it matches an absorption frequency. Air will not become a super-hot plasma from a green laser, no matter how high the wattage if those watts won't be absorbed. Also, even if the light is absorbed, green light doesn't have enough energy to ionize the gas and turn it into a plasma. The ionization potential of O2 is 2.1818599e-18 J, that's 3.3 PHz which is in the extreme UV region and nowhere near the visible part of the spectrum. (BTW, could you phrase your questions a little less elaborately? There's no reason we'd need to know where the thing is located or who supplied the laser.) --BluePlatypus 20:12, 20 February 2006 (UTC)


Since even a twenty watt visible light laser will set paper on fire and a seventy thousand watt beam will melt metal.

I ask the question of why you say that the air will continue just being air?

Since that much energy when impacting any water droplets in the air will vaporize them and turn them into superheated steam.

On further reflection it looks like plasma is not a requirement since regular steam will have plenty of absorption.


Where can I get the reflectivity index of steam?

Or a steam simulator that will show how steam perfoms when pushed by a laser?

The air inside the laser tunnel is a medium. The space around the outside of the laser tunnel is a vacume. The space inside the tunnel is normal air at sealevel pressure.( for a few pico seconds that the experiment lasts)until the effects of the laser are seen.

Normal air deflects a laser beam due to dust/moisture droplets.

So the tunnel walls need to be at the frequency that will produce a wake effect on electrons in the air at the absorption frequency.

I am wondering if any of the released air will manage to stay inside the tunnel and reach the other end when pushed by the laser inside the laser tunnel?

I noticed that the new laser diodes cavity were being made using air spaces to increase the reflectivity index and so reduce the required size for the resonant cavity when using multiple layer films.

Thank you.

R. E. Burrows.

I'm not exactly sure what you want, but this particular section (Directed-energy_weapon#Blooming) seems to have applicable information. Tzarius 06:38, 21 February 2006 (UTC)

Don't they like fried food?[edit]

I read a strange factoid today... that scavengers and carrion-eaters like hyenas and vultures won't touch the corpse of any animal killed by lightning-strike. Is this true, and if so, why? Grutness...wha? 09:46, 20 February 2006 (UTC)

Hmmm. Perhaps they don't like it cooked. Are we the only animals who eat cooked food. (What about dog/cat food is that raw).--Bjwebb (talk) 11:07, 20 February 2006 (UTC)
To my knowledge, regular packaged dog/cat food is not raw. Although, my dogs and cats, as well as those of some friends of mine, love raw chicken and turkey. And yes, it has to be raw. (That reminds me, I was going to work on the raw food diet for pets article...) Cooked poultry bones can splinter and kill the animal from internal bleeding. So to get back to the original question... Maybe it's an evolutionary thing because of the bones getting flash cooked? Just a guess... Dismas|(talk) 11:30, 20 February 2006 (UTC)

Oh dear, another WikiMyth 'strikes' the dust. It says here that giraffes are always getting zapped (disadvantage of being tall), but evidence is difficult to find because they get gobbled up right away by scavengers. [17] --Zeizmic 12:47, 20 February 2006 (UTC)

Nose Weight[edit]

One for the physiologists. Can anyone tell me the approximate average weight of the Caucasian male human nose? Adambrowne666

I had to calculate the weight of an average human hand once. Since I didn't have one in my book bag that day, I decided to build one using materials of equivalent weights. A nose would be much easier as it is just cartilage and skin. But, it is so small and cartilage weighs so little, that I'd be amazed if you got more than 25 grams. --Kainaw (talk) 15:17, 20 February 2006 (UTC)

Rather than your book bag, you should have brought your handbag that day, Kainaw. Thanks for the answer. Adambrowne666 23:07, 20 February 2006 (UTC)

Define nose. Do you mean just the sticky out bit or the whole apparatus behind it as well? DirkvdM 08:49, 22 February 2006 (UTC)
By standing in front of a mirror and holding a ruler up to my own (formidable, but not extraordinarily large) proboscis, I found that I could estimate it as a rectangular prism measuring 1 by 2 by 5 cm. (It's actually a good bit bigger, even with the cartilaginous bit compressed, but I'm accounting for the hollow in the rigid bony part.) That's a volume of about 10 cubic centimeters. Since the density of flesh is about the same as that of water, that yields a mass of 10 grams or so. --Smack (talk) 06:35, 24 February 2006 (UTC)
Thanks again - yes, to answer your question, Dirkvd, I just meant the beaky bit.Adambrowne666 23:27, 24 February 2006 (UTC)

Something related to water and color[edit]

Why does a cloth darken when it is wet?

  • Good question! Let's say you have a light-coloured cloth. You see the brightness and the colour because the cloth is reflecting most of certain frequencies of the light that hits it directly to your eyes. However, when the cloth is soaked in water, the light normally reflected by the cloth is refracted by the water (that is to say, the water causes the light to change direction). In other words, the light that would normally be reflected by the cloth, or whatever is on the other side of the cloth, to your eye is being scattered in other directions. Less light from the cloth hits your eye, so it looks darker. --Canley 10:53, 20 February 2006 (UTC)
So, if it looks darker from some angles, will it always look lighter from other angles? —Keenan Pepper 18:18, 20 February 2006 (UTC)
I think the answer above needs an addendum. I would guess that reflecting off the water allows the light to strike the cloth multiple times, thus giving it more opportunities to be absorbed by the material. I would suspect that this means a darker cloth would get much darker, while a white cloth wouldn't get much darker, since no matter how many times the light touches a white fabric it is still unlikely to be absorbed. StuRat 19:12, 20 February 2006 (UTC)
 \ /
==+================================================== CLOTH
-\---+---+---+--------------------------------------- WATER
  \ / \ / \ / \ (ABSORBED LIGHT)
===+===+===+===+===================================== CLOTH
\                     / (REFLECTED LIGHT)
-\---+---+---+---+---/------------------------------- WATER
  \ / \ / \ / \ / \ /
===+===+===+===+===+================================= CLOTH

Does total internal reflection take place here? Nitin.1704

Are some races academically more intelligent than others? - Literature Review[edit]

What is Academic/Analytical Intelligence?

What are the genetic factors in some races being academically more intelligent?

What are the social factors in some races being academically more intelligent?

What methods are used to measure academic Intelligence?

Many Thanks ---

Check out our article on Race and intelligence. Cheers! --Ashenai 13:22, 20 February 2006 (UTC)

What's the word.. I can't remember it?[edit]

Hmm... interesting question. Possibly "zarf". Grutness...wha? 12:09, 20 February 2006 (UTC)

A zarf is that sleeve of cardboard you hold a hot paper coffee cup with. alteripse 18:03, 20 February 2006 (UTC)
I Googled for the "hardest word to remember" and all the links come up with "sorry". --Kainaw (talk) 15:11, 20 February 2006 (UTC)

Isn't there a word for the feeling of a word being on the tip of one's tongue? Adambrowne666 23:28, 20 February 2006 (UTC)

Words don't like it when you tongue them. It's considered sexual harassment. Raul654 23:30, 20 February 2006 (UTC)
No moreso than tonguing notes. Now that I think of it, concepts in music get quite abused. You tongue notes, stay on the beat, beat time (there's a good joke in Alice in Wonderland about this, if anyone's read it), and you split notes into halves, quarters, eighths, sixteenths...what did the note ever do to you? EWS23 | (Leave me a message!) 01:07, 21 February 2006 (UTC)
Seriously, I think there is a term for a word you know you know, but can't recall - and the paradox of me not being able to recall the term isn't helping ease the frustration eitherAdambrowne666 11:04, 27 February 2006 (UTC)

Miracle babies[edit]

After the 1985 Mexico City earthquake there was a curious discovery in a collapsed hospital of 18 babies that had survived for 9 days in the rubble and were pulled out alive - of which 16 survived. I can find some info about them on Google - but I can't find the medical explanation, which I half remember from some TV show was something along the lines of them slowing down their metabolisms or something. Any help? Sabine's Sunbird 11:20, 20 February 2006 (UTC)

  • In a prenatal class recently a pediatrician told us matter-of-factly that a full-term healthy newborn can be expected to live for for quite a while—I recall him saying a week—immediately after birth with no external food or water whatsoever. This was in response to questions about whether parents should stock up on hydrating supplements etc for fear of breastfeeding difficulties. And of course even with normal breastfeeding newborns are expected to lose a certain percentage of their weight in the first week as they metabolize stored fat while their mother's milk production ramps up (I should say, colostrum gives way to milk proper) and their own feeding technique develops. So for 18 to survive 9 days I'm sure beats some long odds, but probably doesn't require extraordinary explanation. Sharkford 17:01, 27 February 2006 (UTC)

Tape recorder and casette recording[edit]

when recording a casette in a tape recorder, should we keep the volume of the tape recorder at its maximum or at its minimum or exactly where should we keep? Will the sound enter the tape recorder through holes named MIC or through speaker itself?

The sound will enter through the holes near "MIC" which is generally used for the short form of microphone. The volume shouldn't matter. The microphone will just pick up what it can hear and the recorder will then record that. Dismas|(talk) 13:54, 20 February 2006 (UTC)
I presume you are asking your question about an analog rather than digital tape recorder. If so, the answer depends on how the device is designed. For example, some tape recorders do not permit adjustment of the recording volume-- the volume control only affects playback. However, some tape recorders do permit adjustment of the strength of the signal delivered to the magnetic recording tape during the recording process. In this case, it is advantageous to record at the highest volume level that can be accurately reproduced on the tape, in order to maximize the signal-to-noise ratio. However, analog recording tape has a limited capacity to record high volume levels; if this critical level is exceeded, the signal is degraded by "overmodulation," or "clipping" distortion. Some tape recorders have a VU meter that allows adjustment of the recording signal to the optimal strength. Later analog technologies such as companding and Dolby have further advanced the goals of dynamic range and improved signal-to-noise ratio to the point where adjusting the recording volume is not as important as it was in the past.--Mark Bornfeld DDS 14:33, 20 February 2006 (UTC)

Cheap cassette decks will not allow you to change the recording level and use an automatic gain control circuit to select a reasonable recording level. More expensive and/or older decks will often have manual record level controls and usually some level meters. The higher you set the level the better the signal to noise but (potentially) the more distortion. peaking at arround +3db seems fine on most decks i've tried. Plugwash 19:06, 27 February 2006 (UTC)


How is it possible for a fighter jet to fly upside down if the wing is designed to generate lift in the upwards direction if the plane is flying straight?-- 13:47, 20 February 2006 (UTC)

Lift is generated by a wing in two ways: due to the shape of the wing and due to its angle of attack. You see this when a plane is landing or taking off: its speed is low, so the lift is reduced, so the nose is pitched up in order to increase the angle of attack and provide supplementary lift that way. The lift due to angle of attack can be the larger component and can be made to overcome the other component: you see that happening when a fighter pitches its nose downward and goes into a dive, overcoming the normal lift.
Okay, now sustained inverted flight is, in effect, a dive turned upside down. The aircraft's attitude is adjusted to pitch the nose up relative to the ground (down relative to the plane), so the lift due to angle of attack is sufficient to overcome both the weight of the plane and the lift (which is downward) due to the shape of the wing. Of course, this is an inefficient way to fly: there's a good deal more drag then in normal flight. A fighter can overcome that due to its powerful engines, but its speed will be reduced.
--Anonymous, 17:00 UTC, February 20.
Angle of attack is measured relative to the direction of travel, not to the direction the airplane is pointing, or to the ground. When an airplane dives, the angle of attack remains about the same as it does during normal flight, producing as much lift as usual. The reason the airplane descends is that the direction the lift force is pushing is no longer straight up, but rather somewhat forward as well, and it no longer completely counters gravity.
(Inserted in response to this point) This is talking about what happens as a steady dive continues. I was talking about the transition into the dive -- what makes the plane start going down in the first place. --Anon, 00:15 UTC, Feb. 22.
When an airplane is flying upside down, its nose is actually pointing somewhat upwards from the horizontal, while the direction of motion is horizontal. This produces a high negative angle of attack, which causes the wings to stall, so their shape no longer produces much lift. The angle of attack, however, produces a great deal of lift on its own, which holds the airplane up. Also, since the airplane isn't completely horizontal, the engines provide some lift in addition to pushing the airplane forwards. Depending on the airplane, this could be a significant part of what's holding it up. --Carnildo 21:30, 20 February 2006 (UTC)
Further to this, check out Pugachev's Cobra. --Robert Merkel 01:11, 22 February 2006 (UTC)

Is Bowlhover ok?[edit]

Does anyone know how Bowlhover is? I don't want to pry on a sensitive issue, but maybe someone could tell if Bowlhover got any help. I think many of us are concerned.

He's still posting to the original thread, most recently at 04:34 UTC today. --Steve Summit (talk) 17:51, 20 February 2006 (UTC)
Don't know about anyone else, but I'm occasionally checking his "user contrib" list. It's been a while though. If you're reading this, Bowlhover, and feel like letting us know, then please...? Grutness...wha? 23:22, 20 February 2006 (UTC)
I haven't received any outside help (as in, non-anonymous help) as of now. I'm still posting to the "painless suicide" section, and although having 4 hours of classes (instead of 6) on Sunday still makes me panic, I haven't had any more of those horrible panic attacks since yesterday night. At least now, suicide (including painful suicide) is not highly desirable anymore. However, if I have a painless suicide method that is highly accessible, I'll still try it right away. --Bowlhover 17:17, 23 February 2006 (UTC)
Good to know you're still here and at least thinking a bit more calmly about things. I don't think you'll find a painless, readily accessible method - and I hope not, too. Grutness...wha? 00:13, 24 February 2006 (UTC)
Why do you hope that I don't find a painless, readily accessible method? --Bowlhover 04:00, 24 February 2006 (UTC)
It's obvious that quite a few of the Reference desk regulars feel that there are better ways to get through whats happening to your life, Bowlhover. And quite a few of us are concerned about how you interpret the advice of others on this page. Of course, nobody can tell you who to trust, and I can't vouch for the trustworthiness of most people hanging around here, but we all just hope that you will consider our advice as seriously as you do others, because we really have the best intentions in mind, and I'm sure a lot of us are speaking from some sort of experience as well (although we may not be as willing to reveal ourselves publicly as others seem to be). Just keep us abreast of what's up, you don't have to make any difficult decisions alone.  freshgavinG???  04:26, 24 February 2006 (UTC)

Just wondering. If life is such a pain, why do you only want to end it in a painless way? Face it, you don't really want to die. DirkvdM 11:27, 25 February 2006 (UTC)

I do take users' advice seriously, unless the "advice" is clearly not serious. Thanks to everyone who posted to "Painless suicide", "Painless suicide 2", and "Is Bowlhover ok?". I will keep what you said in mind.
"Face it, you don't really want to die." I can't make anyone believe that I really want to die. I know what my own desires are (or aren't), though. --Bowlhover 15:41, 25 February 2006 (UTC)
Well, it is odd that you hate life so much that you want to end it but then fuss about how painful those last few seconds might be. I now this is sounds a bit like I'm saying you should get it over with, but I mean neither that nor the opposite - I just point something out. I hate political correctness and there's been a bit too much of that on this subject. Flame me for being rude, but a general rule in life for me is "If you have problem do something about it. If you can't then just leave it and stop bitching about it". That applies here too, I'd say. DirkvdM 10:48, 26 February 2006 (UTC)

How does a boat sail against the wind?[edit]

How does a sailboat sail toward the wind? I had trouble understanding the Wikipedia explaination. Can it sail directly into the wind, or does it need to aim at an angle? Thanx, Leah

  • Which Wikipedia explanation? Can we fix it? (In answer to your second question, no, a sailboat can't sail directly into the wind; it must proceed at an angle, which is called tacking.) Steve Summit (talk) 19:10, 20 February 2006 (UTC)
  • This is a simplified explaination. Thismight also help, though it's a more technical explaination. I myself am not a sailor, but I have read up on it before. Hope this helps. --Chris 17:30, 20 February 2006 (UTC)
  • Gotta second Chris's first suggestion! Roger MacGregor's explanation is very nice. ("The rudder and the centerboard keep the boat from sliding sideways, so it squirts forward, much like a watermelon seed shoots out forward when you squeeze it between your fingers". Lovely!) --Steve Summit (talk) 19:39, 20 February 2006 (UTC)
Nope, they can't sail directly into the wind. In simplified terms, old sailboats (square-rigged ones) were basically pushed by the wind directly, so their best point of sail (as it's called) is downwind (with the wind directly behind them). Modern sailboats (with triangular sails) work on a different principle, the same as a wing of an airplane. They tend to sail best relatively close-hauled (that is, close to the direction of the wind, although not into it). So if you need to go directly into the direction of the wind, you'll have to tack in a zig-zag pattern. 'Tacking' is changing the direction of the boat from having the wind on one side of the bow to the other when going upwind, as opposed to a 'jibe' which is doing the same going downwind. --BluePlatypus 19:56, 20 February 2006 (UTC)

Ah Hah! Got it! Thanks so much to yous, Steve, Chris, & Platy. The MacGregor discussion is really excellent. I went back to the Wiki explainations to find out why I had been confused. They were "sailing ships" and "sail." Yes, I think they can be fixed for introductory readers, by providing diagrams of how the wind interacts with the sails. Other than that, the Wikipedia explainations are quite good and very indepth. I could tell the Wiki writer had put much thought and work into the task. I still learned a lot.

When I saw it from Macgregor's "floor plans" I began to see the watermellon seed, one of the basic principles. One other thing is needed too, in Wikipedia. There needs to be several more pictures, particularly with labels of the different sail names, and what each does. (this one pulls the boat, this one squirts).As well, as a few diagrams of how the wind interacts with the sail. Macgregor's bird's eye view is priceless.

BluePlatypus, thanks especially for your summary. What you wrote really is the basics of sailing. You also explained the meanings of some important terms in a simple way I could understand, i.e. tacking, jibe, point of sail. Why don't you consider adding to many of the stubs on this topic? I've just moved near the ocean in Australia. Because of this discussion, now I think I might like to try this. Any suggestions for a good beginner boat? --Leah

Well it's all in sailing which links to our article on tacking. If the description there is unclear, I'm sure the editors of the article would like help making sure it is understandable to landlubbers. - Taxman Talk 19:15, 21 February 2006 (UTC)
I don't know if you've got 'em down under, but some of the best sailing I've done has been on a Laser. None of the "how to sail" descriptions really make sense until you go out in the wind and start noodling around (at which point it ends up being much easier than it sounds), and a small, forgiving, responsive, one-person boat lets you "feel" it all in a nice, heuristic way. Have fun! --Steve Summit (talk) 19:15, 21 February 2006 (UTC)
Yeah. Originally I was only curious about the physics, about how it works with the wind and all. But now i think it sounds like fun to actually do. I'm glad to hear you say that it is easier done than said. Maybe a little like trying to explain the parts of a bicycle and then how to ride one. I bet you just gotta do it to know it. Still, I hope someone will add a few diagrams and pictures to the Wikipedia. ~Leah
I use tacking sometimes in The Wind Waker when I'm too lazy to change the wind direction :P --Optichan 15:41, 22 February 2006 (UTC)

name of a rare disorder[edit]

I've read of a rare disorder that causes the human body to respond to any kind of trauma by growing bone in the affected area. I believe it's congenital. Does such a condition really exist, and if so, what is it called? I've been through various lists and categories of skeletal and congenital disorders, but have turned up nothing. —Charles P._(Mirv) 18:38, 20 February 2006 (UTC)

Well, this isn't what you asked, but bones always strengthen themselves (via calcification) in response to stress. (Our bone article mentions this briefly.) Steve Summit (talk) 19:06, 20 February 2006 (UTC)
I've heard of that. I don't know what it is, but apparently the person gradually turns into a statue over a period of two to three decades, then dies. Black Carrot 20:07, 20 February 2006 (UTC)
It might be pseudohypoparathyroidism, a hereditary condition also known as Albright Hereditary Osteodystrophy. This reference mentions soft tissue calcification as a feature: [18] Or it might be pseudopseudohypoparathyroidism: I think saw a description of that somewhere that's quite close to Mirv's description (bony tissue forming at random in the body.... nasty) . But I'm not an endocrinologist, so who knows? Malcolm Farmer 20:53, 20 February 2006 (UTC)
As it happens, I recall watching a documentary about that same disease just a few years ago. All I can remember is that the name was a three-letter acronym, but after some googling it appears that what you're looking for is fibrodysplasia ossificans progressiva (FOP), only about 200 cases of which have ever been reported. —David Wahler (talk) 21:10, 20 February 2006 (UTC)
That's the one. Thanks. —Charles P._(Mirv) 22:34, 20 February 2006 (UTC)

Changes in Axial Tilt of the Earth[edit]

My father recently informed me that he heard it from a government source person that the axial tilt of the earth recently increased by a couple of degrees due to the earthquake that caused the Sri Lankan Tsunami. He said the government is trying to keep this "hush, hush" so people won't panic. Is there any truth to this rumor?

Thank you in advance! Aedenbow 18:40, 20 February 2006 (UTC)

No. A couple of degrees would be (2/360)*24000 miles = 133 miles of shift. I think you would have noticed if you were suddenly shifted 133 miles. Any shift would be far less than that. StuRat 18:53, 20 February 2006 (UTC)
(via edit conflict) There might be a grain of truth to the rumor: see 2004 Indian Ocean earthquake#Power of the earthquake, which indicates that it did cause a miniscule (no more than a few inches) wobble. Rumors tend to exaggerate.
However, no government (I assume the U.S. government was meant) could hush up several degrees change in the axial tilt of the Earth, which (as StuRat notes) would not be a subtle thing. —Charles P._(Mirv) 19:02, 20 February 2006 (UTC)
Indeed. Momentary sanity check: even if the shift was completely unnoticed by all the earth's population when it happened, it'd immediately shut down all satellite television, as the recievers move out of line-of-sight... and imagine someone managing to hush that up ;-) Shimgray | talk | 23:12, 20 February 2006 (UTC)
This is also highly unlikely because in the normal periodicity of the Earth's axial tilt, it only varies three degrees (from 21.5 to 24.5 degrees with a period of 41,000 years). See axial tilt and inclination. -EWS23 | (Leave me a message!) 20:07, 20 February 2006 (UTC)

"Highly unlikely" is too weak. This is arrant nonsense and should be slapped down as such. The amount of energy needed to change the Earth's rotation "by a couple of degrees" would be several orders of magnitude beyond what an earthquake releases. Even a very big quake. You're talking about a significant motion of the entire mass of the Earth, whereas a quake just moves a small section of the crust, and most of it not very far.

Charles P.'s response is correct as far as it goes, but confusing the real effect he talks about -- one detectable only by sensitive instruments -- with the sort of thing the original poster talked about is like confusing a grain of sand with a mountain.

Oh look here's someone (a geology professor) with a web page directly on topic, and another related page worth reading.

--Anonymous, 21:35 UTC, February 20.

No fair being snotty and amonomonous! I'm grumpy and get all the gumpf back! --Zeizmic 22:54, 20 February 2006 (UTC)

Pain & Torture[edit]

BTW, this is for English class. We're studying the Inferno, and have to make up our own idea of hell. I'm not psychotic. Does anyone know where I can find current or definitive research on the subject of pain, both physical and psychological? It seems to me the tortures used by Dante in the Inferno were haphazard and unscientifically applied. I'm interested in three things: Different forms of pain and their effects on different people, the effects of pain over time (if you were really in excruciating pain for millenia, would you just get bored?), and how different pains combined interact. By pain, I mean everything from searing heat to exhaustion to dismemberment to terror, horror, despair and disgust. Anything you can find. Black Carrot 20:04, 20 February 2006 (UTC)

Hell is a teacher inquiring about our personal fears and horrors to get a tighter control. Beside that, I assume all such research is strictly confidential. The Infidel 20:48, 20 February 2006 (UTC)
Wow, that was deep. I wouldn't figure all of it would be confidential, especially in countries that torture openly, and there are certainly hundreds or thousands of years of research that are public domain by now. Black Carrot 22:05, 20 February 2006 (UTC)
Just for kicks, read the short story "I Have No Mouth, and I Must Scream" at this link. --Uthbrian (talk) 00:59, 21 February 2006 (UTC)

read Journey Into Madness : The True Story of Secret CIA Mind Control and Medical Abuse, by Gordon Thomas, Bantam, 1989, ISBN 0553053574 about Aziz al-Abub, trained by Americans, now a torturor of Americans. The hard part is keeping the victim from dying, and thus escaping. This is where medical knowledge comes in; knowing how far to go.

Americans at Abu Ghraib are amateurs.

also read about Nazi death camps and their "experiments"

Amnesty International probably has some relevant material

However, I think your teacher wants you to use your imagination, like Dante did, and come up with special tortures, like "being in Bob Zarbatani's gym class. Forever." Or something like that.

for other hell in literature, read Sartre, No Exit , a play, (hell is other people)

And to really impress your teacher read the all time classic "In the Penal Colony" Franz Kafka. short story. --GangofOne 03:42, 21 February 2006 (UTC)

Eddie Lee: "Anybody who showed up was going to join Lim Lee in the Hell of Being Cut to Pieces."
Jack Burton: "Hell of what?"
Eddie Lee: "Chinese have a lot of hells."
Tzarius 06:23, 21 February 2006 (UTC)

If you think the ppunishments described by Dante in the Inferno were haphazard, you need to restudy that work. - Nunh-huh 09:58, 21 February 2006 (UTC)

The idea of culpability and punishment is so strong that people, inside some organised religions, delected in designing different tortures for each sin.
The goal of each torture method is directed to the right sin, so it is not hazard ; there is a link - as thin, linguistic and out of our logic as in homeopathy - between them.
The real suffering of the tortured is another problem. Exquisite (chinese ?) tortures may give exquisite results too. --DLL 20:27, 21 February 2006 (UTC)

I appreciate the suggestions, but most of them are going in the wrong direction. I'm looking for actual factual information about the science of torture and the various methods available, so I can do a better job than he did. (And yeah, I realize he meant the punishment to fit the crime. They're still haphazardly applied.) The things I'm having the most difficulty finding out are:

  • Assuming a person can be tortured indefinitely without loss of flesh or eventual death or unconsciousness, will they continue, forever, to feel the same way, or will the horror of it start to dim and the pain start to dull? Will they become jaded, and eventually bored? And I realize, of course, that this moves firmly into the realm of speculation and educated guessing.
  • What would be the effect on a normal psyche of having nothing to think about, at all, ever? After the first few millenia, I'd think you'd have run out of games to play in your head, and I'm wondering what would happen to you then. Black Carrot 00:52, 22 February 2006 (UTC)
You want to do "a better job" than Dante Alighieri. Not exactly short on self-confidence, eh? Anyway, I think the questions are essentially unanswerable; once we start talking about tortures that can be prolonged forever, we're outside the realm of science. If God or the Devil (whichever is responsible for Hell according to your theology) can keep you alive (or however you want to put that) through these circumstances, then he can also keep you from getting bored. Or at least there's no reason to think he can't. Frankly I think you're missing the point of the exercise. --Trovatore 01:14, 22 February 2006 (UTC)
I didn't say I'd write better, or that my theology would be more accurate, just that my version of the tortures of hell will make a lot more sense to me than his does. And no, we aren't entirely outside the realm of science. The only conceiveable reason people would actually have natural bodies inside a physical hell is that it has to be that way - there are some things god can't or won't change about us. Otherwise, it'd just be some unimaginable swirling world of infinite pain. Hell, he could even give us new senses if he wanted to, just for the chance to make those senses hurt. It follows, if god wants to keep us more or less in our original form and mind, that he wants us to feel pain and suffering within the bounds of what we could on earth. So, however it works here is how it works there, but forever. So, if people with gout can eventually get used to the pain and live happily despite it, it seems to follow that damned souls might too. I was just looking for basic information in that area. And I understand completely the point of the exercise (which I chose out of a list, containing such hits as the Restaurant of Hell and What Classes a Damned Soul Might Teach in College): to keep us interested enough in the book to pay attention to it, and to add an easy major grade to our averages. Black Carrot 02:28, 22 February 2006 (UTC)
Bravo! You are making interesting points. My advice is, spend half an hour, read story Basketball by Dyachenko. In my mind, you'll find some "flesh" for your ideas. Imho, one of it's points is, one may get used to physical pain, but psychological pain would remain with you forever... But "psychological" hell is nothing else than the hell that every of us bears in himself. Btw, this story is translated from Russian, so forgive it's strange names or may be language that could be better. 17:32, 23 February 2006 (UTC) Although my personal point of view is that there's nothing after death, just there remains nothing to be able either to think or to feel pain. 17:32, 23 February 2006 (UTC)

Somewhat relatedly, suppose there was a chemical cocktail that induces pure pain from all the relevent sensory nerve receptors, could be varied in duration, and had no permanent physiological effects (aside from the psychological). Would such a substance be an effective form of torture or deterrent? I mean, could it supplement imprisonment as an effective crime deterrent? Say, half an hour of (physically harmless) unbearably agonising hell instead of six months in prison? I have to admit, it does sound good on paper. Tzarius 07:36, 22 February 2006 (UTC)

About physical pain: Severe pain makes you pass out. Lesser pain inflicted continuously eventually is ignored by the brain. Lesser pain inflicted discontinually produces psychosis wherein the "pain" becomes interpreted (along with many other aspects of reality, sometimes) as something other than pain. Pain is all in the mind. It is an interpretation of information. That's why buddists can burn themselves to death while sitting stoicly. To create real torment, you need to create emotional pain. You want the subject to be maximally aware (e.g. caffein), believe they are in control (you are "free"), yet their "errors" keep causing physical pain to themselves and a loved one (who is helpless). That's why "torture" doesn't work, but phychological techniques (that can include "minor" pains, especially fright) do. Anticipation is a grat tool. WAS 4.250 17:11, 22 February 2006 (UTC)

See, that's helpful. Thank you. Now, why or how does pain make you pass out? I've heard it has something to do with 'going into shock', but I don't really know what that means. What do you mean by pain 'becom[ing] interpreted... as something other than pain'? What does it turn into, a sense of pressure or something? And yeah, screwing with someone's mind is an important part of torture. One great idea I ran across in my research is picquet, where most people will spend an entire day trying desperately (and pointlessly) to reduce the pain. The only problem is that even the dumbest person will eventually get wise to the system and collapse into apathy after the first few billion years. And a lot of sinners know how to work the system way faster than that. That's one of the things that bothers me most about some of Dante's punishments, is that they don't seem to take into account how people will actually act. Black Carrot 20:18, 22 February 2006 (UTC)

Cognitive scientists[edit]

Can I tell the difference between the thought patterns of a 'sane' person and an 'insane' person? by thought patterns I mean, their thinking style, beliefs,etc. I have no knowledge of any objective 'meassurement' system regarding this...and also, even though I study psychology, I find it a little conceited that we label mental illnesses when in fact we don't even know what is 'the ideal behaviour' for a person, since that boils down to philosophy in the end. and I havent found any satisfactory concepts searching either.:S .--Cosmic girl 22:18, 20 February 2006 (UTC)

I studied Cognitive Science for a while, and this is a fairly interesting question. Unfortunately, the term "insane person" is very imprecise, and encompasses a huge variety of abnormalities.
Brain activity can be measured in a variety of ways, and abnormal activity (or lack thereof) can indeed point to certain mental abnormalities or illnesses.
I'd love to give you more specific information, but your question was terribly vague, and there's no way to reasonably cover the entire subject in a Reference Desk question/answer format. :) --Ashenai 22:23, 20 February 2006 (UTC)

ok... what I'm saying is that there's no way of telling objectively what is 'right' and what is 'wrong' in mental health matters, we may be able to say what is useful...but never what is in more accordance with reality.

for instance... a Descartes is seen as a great philosopher for coming up with the argument for philosophical skepticism...right? but then, if just a random person says that a demon may be fooling him into believing something, he's automatically a schizophrenic person... in this case, it's all about the confidence... then we have nietzches superman vs. people with 'antisocial personality disorder', then we have the mystics vs the schizophrenics and hypomaniacs...then we have the 'poetically melancholics' vs. the depressives. the pioneers vs. the ones with 'authority defiant dissorder' I the only one that sees the irony and stupidity in all this? I mean, what distinguishes one from the other, is it the confidence? it seems so... then there is perseverance as opposed to OCD, there's energy as opposed to hyperactivity... and I'm not an advocate of anti-psy. or scientology...I think they both suck actually... I just think we need a SCIENTIFIC model (like cognitive science) in the psychiatry and psychology classrooms...for real.--Cosmic girl 23:00, 20 February 2006 (UTC)

Overdiagnosis and overmedication of psychological issues (ADHD or depression, for example) is a real (though pretty contentious) issue, I agree. Unfortunately, cognitive science isn't really capable of filling psychology's shoes. Yet. We still do not know enough about the connection between neurobiology and actual human cognition. So we're kind of stuck with psychology, for now. Yes, it can stink of pseudoscience, at times. But we don't have anything better, for now. --Ashenai 23:10, 20 February 2006 (UTC)ç

I agree...we still have to take care of the mentally ill no matter if we don't know all about the field, or even if we don't know what's the 'ideal' for a person to be.--Cosmic girl 02:06, 21 February 2006 (UTC)

I'd say overdiagnosis and overmedication is a far smaller problem than the opposite. With ADHD, it's rather simple (in my opinion). Say for the sake of argument, the worst possible scenario, that the patient doesn't have a problem. The drugs administered for ADHD are not mood-altering (at those doses), they're not mind-altering either. The person taking it is fully capable of making a rational decision on whether they're being helped and whether the risks outweigh the benefits. If they feel it helps them - what's the problem? Then it's just like plastic surgery - a medically unnecessary risk taken to help conform to society. But if the patients feel helped, I don't see anything unethical in it. (at least with ADHD or depression you can go off your meds. Surgery is pretty much irreversible). Depression is of course somewhat more problematic, since the drugs used are mood-altering, which makes it more difficult for the patient to assess the effects. However, I feel Cosmic Girl is grossly exaggerating in smoothing over the differences between disorders and personality traits. OCD has nothing to do with perseverance. Perseverance is voluntary. It is not done in the face of irrational fears and anxiety. Having perseverance doesn't ruin your quality of life. There's a difference between trying until you fail, and repeating a meaningless jesture out of fear of death. There's an equally big difference between energy and hyperactivity. Energy is feeling like getting up and running around. Hyperactivity is getting up and running around even though you really wanted to sit still. I could go on, but you get the point: It's easy to come to the conclusion that these things must be overdiagnosed if you overgeneralize the symptoms. Since a definition was asked for, I'll give one though: When your problem (whatever it is) is involuntarily and seriously impinges on your quality of life, then you have a mental problem. That's basically the distinction between being 'sad' and being clinically depressed, but it applies well to everything else too. --BluePlatypus 01:30, 21 February 2006 (UTC)
I completely agree, I was exagerating a little...and your answer really helped me understand my mistakes and things I was missing. thank you!:), and maybe I sounded like an anti-psychiatrist or a scientologyst or something like that, but actually I completely disagree with them...

by this question I was trying to gain some insight to the differences of the cognitive structures of a healthy person and of a mentally ill person...and you pointed it out ok. actually, I think your definition of mental illness is way better than the ones I've read in books.--Cosmic girl 02:12, 21 February 2006 (UTC)

I am not a doctor, but I think psychologists and psychiatrists usually check the Diagnostic and Statistical Manual of Mental Disorders (DSM). This book defines various mental disorders by using checklists for symptoms of each disorder. By the way, for a historical perspective, consider that homosexuality was once considered a mental illness. --Uthbrian (talk) 00:55, 21 February 2006 (UTC) I knew that homosexuality was considered a mental illness..I don't think it is one, since it seems to be more voluntary than involuntary and also it doesn't make the person suffer , I mean, it doesn't go against the persons will if that person doesn't live in a society that condems it. but I do think that homosexuality goes against evolution more than it does against religion... but I have nothing against it, it's ok.--Cosmic girl 02:16, 21 February 2006 (UTC)

The DSM has lists of symptoms, but not checklists. Diagnosis isn't done by checklists (It's mental health, not a women's magazine! :) ). However, checklists are used as tools in diagnosis, for getting indicators of where to look closer. At least that's been the case with every psychiatrist I've met. --BluePlatypus 01:25, 21 February 2006 (UTC)
Cosmic girl, can you name anyone who has voluntarily chosen to be homosexual? Or heterosexual, for that matter? Evolution has produced homosexuality, so it seems odd to say that it goes against evolution. I'm sure your approval was well meant, but it's really not necessary. JackofOz 01:35, 22 February 2006 (UTC)
I think a better way to word Cosmic girl's statement is to say that homosexuality shouldn't be considered a mental illness because it seems to be determined on a social level, unlike any kind of illness (actually, maybe that statement should just be striked/strucken. It's a classic argument that is really hard to "prove" verifiably, and I don't think anyone is trying to imply anything here). About evolution, I'm not sure how to argue that; I just figure that the basic goal of a member of a species involving evolution is to contribute its own genes to the pool.  freshgavinG???  16:23, 22 February 2006 (UTC)
I think you missunderstood me, I don't think there's anything wrong with homosexuality at all...
I was just saying, like Freshgavin says (hee understood me)that homosexuality is something on the cultural level and on the personal choice level, and since it doesn't impair the person's cognitive ability and/or ability to care for themselves,or bother them, then it shouldn't be considered an illness...
and also,I still think that homosexuality goes against evolution...but evolution is not a conscious being so don't take this statement like it's meant to condem homosexuality...
it just goes 'against' it, since there's no reproduction in homosexuality, BUT we are a species capable of controlling reproduction now, so we don't have to bother that much about that since we are not running out of humans...--Cosmic girl 19:25, 22 February 2006 (UTC)
I know you were saying it's OK, but that in itself was the issue I (clumsily) raised. If you can put yourself in the position of judging whether it's OK or not OK, that means it's something to be judged, rather than something simply to be accepted. A person can choose to engage in homosexual acts, or choose to have a relationship with a person of the same sex, etc. But whether they are a homosexual, the fact of their sexuality - this is not a personal choice, just as it is not a personal choice to be heterosexual, or left-handed, or Chinese, or green-eyed. They're the cards you're dealt and there's nothing you can ever do about it (or should even try). JackofOz 20:06, 22 February 2006 (UTC)

Mental illness, in current medical science, is a "clinical diagnosis". What that means, is that a medical doctor (or specialist like a Psychiatrist) makes a diagnosis based on taking a history from the patient, family members, and examining the patient. There is no blood test, brain scan, or EEG to make a diagnosis of mental illness - it really is a judgement call. The DSM-IV can be used as a guide. (It was designed to define mental illnesses for the purpose of clinical research, so that the subjects would all be more or less similar.) Some mental illnesses (or symptoms) are easier to diagnose than others. Take for instance, psychosis, a symptom of schizophrenia. It could be defined as loss of connection to reality, such as hallucinations or false fixed beliefs. Whether someone is experiencing psychosis can be up to interpretation. Someone who believes that they are the Messiah and can bring about the end of the world is probably psychotic. However, someone who believes they can communicate with Jesus Christ may or may not be psychotic, depending on the particulars (such as their religion). - Cybergoth 03:33, 21 February 2006 (UTC)

Cemistry: separation of the componets of a Mixture.[edit]


I have search several sites and different books and haven't had any luck so today one of my classmates told me to check this site out. so here goes. if anyone can help me with these questions please i really appreicate it.

1. how to separate barium sulfate, BaSO from NHCl.

2. How to separate zinc chloride, ZnCl2, from zinc chloride, ZnS.

3. How to separate tellurium dioxide TeO2, from SiO2.

4. Naphthalene sublimes easily, but potassium bromide does not. How could you separate these two substance.

If they have different densities, you could try a centrifuge. For the last one, you can leave the mixture out and allow it to sublimate until only potassium bromide is left. StuRat 23:18, 20 February 2006 (UTC)
Of course, if you wanted to keep both the napthalene and the potassium bromide, you'd have to do it in a container and let the napthalene condense back. Black Carrot 00:12, 21 February 2006 (UTC)
For the first, I assume you mean barium sulfate (BaSO4) and ammonium chloride (NH4Cl). If that's the case, note that barium sulfate is water-insoluble while ammonium chloride is highly soluble. Basically, I think you could dissolve the mixture in water, which would leave behind the insoluble barium sulfate. Filter this out, and collect the liquid. The liquid should have dissolved ammonium chloride (with a miniscule amount of barium sulfate). Evaporate the water from the liquid, leaving behind crystals of ammonium chloride. By the way, if there's a chemist around, feel free to correct me :-) --Uthbrian (talk) 00:31, 21 February 2006 (UTC)
Also, for the second case I assume you mean zinc chloride (ZnCl2) and zinc sulfate (ZnSO4). Read the zinc chloride article and look for its solubility in ethanol. Zinc sulfate is insoluble in ethyl alcohol (ethanol) [19]. Hence, follow the same procedure as above, but use ethanol as the solvent instead of water. --Uthbrian (talk) 00:37, 21 February 2006 (UTC)
Actually, I'd assume the poster means zinc sulphide (ZnS). GeeJo (t) (c)  21:34, 21 February 2006 (UTC)
Uh-oh. Good point, GeeJo. It looks like zinc sulfide is water-insoluble while zinc chloride is water-soluble, so you might be able to do the same as with the BaSO4 & NH4Cl separation. However, I missed something about zinc chloride-- apparently, the article says "Concentrated aqueous solutions of zinc chloride have the interesting property of dissolving starch, silk and cellulose, so that solutions cannot be filtered through standard filter papers." So, you may have to use a sintered glass filter.
You might have to use a sintered glass filter with the BaSO4 & NH4Cl also [20]. --Uthbrian (talk) 00:44, 22 February 2006 (UTC)
For number 3, note the difference in melting points between tellurium dioxide and silicon dioxide. I'll let you figure this one out. --Uthbrian (talk) 00:39, 21 February 2006 (UTC)

February 21[edit]

referenced memory at "0x1001cb1". The memory could not be "read".[edit]

Ok, I know that's not good, but just how bad is it?--Memref 01:02, 21 February 2006 (UTC)
  • What were you doing when you got the error, how many programs did you have running? Anything new you installed before the problem occured? How many free disc space have you got left? Please give us a little more details. - Mgm|(talk) 09:13, 21 February 2006 (UTC)
There's a way to artificially cause this kind of error to happen in Windows Media Player. Open an mp3 you have in WMP, and as soon the WMP window becomes visible, close it. This causes it to terminate while it is opening the file, which makes it throw that error. However, it seems to have happened in explorer.exe for you, which is worse. Explorer was probably trying to read something in memory that's no longer there. It's hard to suggest a cause for it though... could you tell us what exactly you were doing just before the error occurred? -- Daverocks (talk) 07:34, 22 February 2006 (UTC)
I've gotten a similar errors before. Don't know the cause of it, but I find the quotation marks around "read" pretty funny. --Optichan 15:36, 22 February 2006 (UTC)

sound like bug flapping wings in ear[edit]

For the past two weeks or so, on and off I've had an annoying and distracting sound bother me. There's been a sound in my ear (only one ear I think) that sounds as though there was an insect in there flapping/buzzing it's wings. Once it starts happening it pauses briefly at seemingly random times. What is this? How can I get it to stop?

I realize that I could go to my doctor, but I'm pretty sure this has happened to me several years ago and it turned out to not be a big deal. Flea110 02:07, 21 February 2006 (UTC)

Tinnitus --Zeizmic 02:58, 21 February 2006 (UTC)
Unusual sounding tinnitus if it is... the other possibility, of course, is that something flew into your ear (in which case, sit with your ear close to a light source like a lightbulb or torch for a while, see if anything escapes (seriously... this does happen, and the sort of insects involved are attracted by light). Grutness...wha? 07:19, 21 February 2006 (UTC)
Sounds to me like a fasciculation. I occasionally get this sound in my ear, but it only lasts a few seconds. Having the ear syringed might help. --Shantavira 16:29, 21 February 2006 (UTC)
So that's what that's called! I always thought I was just imagining it.  freshgavinG???  16:06, 22 February 2006 (UTC)

5th grade science project[edit]

How does design affect how far a model plane can fly? Also what is a good idea for a graphic presentation on said question. All suggestions will be greatly appreciated.

  • To make a model plane fly a good distance, you need to make the design aerodynamic. I'm sure your teacher has an idea of what he/she wants to see in the presentation, but I would mainly talk about what you did to optimize the design. - Mgm|(talk) 09:16, 21 February 2006 (UTC)
Our paper airplane article could be helpful. Black Carrot 17:15, 21 February 2006 (UTC)
Assuming "model" means that it may be powered, you can take into account a balance between a power source, a motor, and size. A larger motor will usually make it go faster, but that takes more power and a larger plane. A larger plane makes it go slower. More power will require more power storage, which also makes it go slower. So, for each motor type/body type/power storage type, you will find a sweet spot where they all balance out perfectly and you maximum performance. --Kainaw (talk) 17:51, 21 February 2006 (UTC)

Major causes of death or illness for the most slovenly in a Western democracy...[edit]

Hypothetical situation (or, rather, let's hope so):

  • Take Experimental Subject X who:
    • Is a young human of either sex.
    • Lives in a house which he or she never leaves (food is delivered and basic services such as plumbing are tended to) located in a modern Western democracy of the first world.
    • Never bathes or showers.
    • Does washing up of clothes and crockery but only incompletely, ie may often eat from plates that are not entirely clean, wears clothes for longer than any company he or she would have to the house would prefer.
    • Rarely cleans the house, although we are assuming that no vermin or scavenging animals are able (or willing) to enter the house (no rats or mice).

What sort of illnesses and/or cause of death is this person liable to be prone to? What common viruses or parasites are liable to develop or flourish in such an unkempt environment? What other health problems might Subject X encounter? --bodnotbod 04:10, 21 February 2006 (UTC)

There are few risks in your scenario other than social isolation, family or community opprobrium, and lack of exercise. All of your "unhygienic" habits are mainly violations of cultural norms rather than health risks. Dalembert 05:03, 21 February 2006 (UTC)
Indeed. I do recall a study showing the adverse effect of overzealous cleaning (in children), namely that the child's immune system hadn't had a chance to recognise dangerous pathogens before being weakened by unrelated events (overexertion, hypothermia etc). So it's good to get exposed, while your body is strong. Tzarius 06:14, 21 February 2006 (UTC)
Interesting. Thanks. And Dalembert I am at pains to point out that these are not "my 'unhygienic habits'"! I mean, I'm no martyr to the dustpan and brush, but - blimey - bathing and eating off clean plates isn't beyond me. --bodnotbod 09:58, 21 February 2006 (UTC)
Oh, OK, you were asking on behalf of a friend. Got it. Dalembert 11:37, 21 February 2006 (UTC)
Tzarius, while the Hygiene hypothesis has growing evidence to support it, the most common results are things like asthma and allergies that don't carry very high mortality rates, or at least not as quick. From my non-medical professional opinion, in the scenario above the most likely problem would be food poisoning. Even if not acute such as botulism, the exposure to enough germs and toxins can eventually shut down the liver. (I forget the specific name, I'm guessing our Md Wikipedians will fill it in.) I would think the next most likely killer would be a urinary tract infection, but that of course could be treated, and if treated wouldn't be as likely to kill. - Taxman Talk 19:04, 21 February 2006 (UTC)
My guess is that the quality of the food would be a (or the) critical factor in this scenario. If the food is basically junk food, then life expectancy might be no more than a few months — see Super Size Me. But with a healthy diet, if it was me, I'd expect to go crazy before I died of any scenario-related cause. — Johan the Ghost seance 21:14, 21 February 2006 (UTC)
The scenario described is a stereotypical dope-house. When using opiates, bathing and wearing clean clothes will open the pores and diminish the high. So, it is normal to refuse bathing in that situation. Add to that the inability to focus on common functions, such as using a toilet, and the house quickly becomes dirtier. Food is ignored in place of drugs. So, it is easy to see that a dope-house can be worse than the scenario depicted, but at least as bad. That leaves the question: how long can a person survive in a dope-house? Months. Assuming they don't OD, they can just keep going and going and going. The human body has an amazing ability to try and keep going. But, it will hit the point of no return when it begins consuming itself. It is very painful, but someone high on opiates wouldn't notice. --Kainaw (talk) 02:02, 22 February 2006 (UTC)

Also note that an accident is likely in such a house, such as slipping on something left on the stairs and breaking one's neck. StuRat 03:05, 22 February 2006 (UTC)

5th grade social studies project[edit]

What is a great idea for a graphic presentation on showing how buddhism developed? Thank you

  • First you'd need to read up on Buddhism, then you'd need to find relevant images. Like one of Buddha, people during meditation and stuff like that. -- Mgm|(talk) 09:19, 21 February 2006 (UTC)
You can also get a big map of India and Southeast Asia and use arrows and images to show how Buddhism travelled and how it changed as it did so. Add little year markers to it and you can a nice map that may be used as a timeline to see the progression from original Buddhism to all the forms we know of today. --Kainaw (talk) 17:54, 21 February 2006 (UTC)

audio power[edit]

What is the exact relationship between WATTS and PMPO watts? That is ,Is there any formula to convert one to another?

In short, no not really. Have you read Audio power? --Martyman-(talk) 07:26, 21 February 2006 (UTC)


I'm trying to find information for a theoretical invention useing magnets and electromagnetic fields. These fields will be very strong and require many hours a day of exposure. I was wondering if this is dangerous and can cause side effects like cancer and radiation sickness. I know this is a debateable theory for others devices like cell phones, but this is a much much stronger field. Thank you for any advise and information you can give me.

Not a direct answer, but I was hoping to use large-scale magnetic fields as part of an MSc thesis experiment, and was told that I'd never get it passed by the university ethics committee because it could cause long-term problems for the subjects. Grutness...wha? 08:52, 21 February 2006 (UTC)
Strength of the field, by itself, doesn't matter so much — strong fields are used in NMR labs and in hospital MRI scanners without many problems (provided you don't have a pacemaker etc.) As to the duration, it's a fairly contentious point as to whether spending extended periods near magnetic fields causes health problems, with data open to interpretation in both directions. But if it turns out to be so, the strength of the field will definitely be a factor. Given the question mark over safety, it'll be pretty difficult to get approval for anything involving long-term exposure to such fields. GeeJo (t) (c)  09:01, 21 February 2006 (UTC)
see Bioelectromagnetics and Bioelectromagnetism. These are currently researched fields, nobody really knows. You won't get radiation sickness, though; that's from ionizing radiation, Xrays, gamma rays, or particle radiation. If there is an effect it is more long-term and subtle, at least for static fields. For rapidly changning fields it might effect ionic operations in transmission of nerve impulses. Michael Persinger researches effects of rapid magnetic changes on the brain and consciousness. Definitely an effect, whether a detrimental effect is unclear. GangofOne 22:29, 21 February 2006 (UTC)

Stab wounds to the heart in fact and in fiction.[edit]


The heart is more centrally located than the layman might think (certainly this layman, anyway). It appears rather well protected by the ribs and sternum. Are fatal stab wounds to the heart more a thing of fiction than liable to occur in real life? --bodnotbod 10:43, 21 February 2006 (UTC)

Not if the stabber knows what he's doing, and remembers that the best way to a man's heart is through his liver. (a knife thrust up under the ribcage can easily reach the heart.) —Charles P._(Mirv) 16:23, 21 February 2006 (UTC)
Or the attacker might get lucky and have the knife go between the ribs. StuRat 21:38, 21 February 2006 (UTC)
Here's an article on "Penetrating Cardiac Trauma" [21]. It mentions that 40% of cardiac stab wound victims arrive at the hospital alive. The victim not only has to worry about hemorrhage, but also cardiac tamponade. --Uthbrian (talk) 01:12, 22 February 2006 (UTC)
And here I thought tamponade was the rather suspect version of lemonade your ex-girlfriend might give you the next time you see her after an unpleasant breakup. StuRat 08:05, 24 February 2006 (UTC)
Also, in movies you often see somebody getting pricked once and immediately their eyes roll back and they drop. In reality the victim is more likely to get stabbed a couple dozen times or more. That's about when they stop saying, "Hey cut that out!" and start getting serious about being dead.  freshgavinG???  15:58, 22 February 2006 (UTC)
Actually, it's only henchmen who drop immediately. Good guys in minor roles have time to pass on a last message, while the chief bad guy gets time to look disbelieving, say something in disgust, sneer and only then expire. It doesn't matter whether they were stabbed or mown down in a hail of machine gun fire. Union rules, you know. Notinasnaid 17:56, 22 February 2006 (UTC)
I can only assume that heroes have stronger hearts, which would make sense.  freshgavinG???  17:57, 22 February 2006 (UTC)
Thanks all. As a supplementary question, anyone able to tell me of the likely consequences of a stab wound in one lung (or, for ease, point me at the right articles)? --bodnotbod 05:08, 23 February 2006 (UTC)
That would cause a sucking chest wound, which begs the question - don't all chest wounds pretty much suck ? StuRat 08:09, 24 February 2006 (UTC)
Pneumothorax and hemothorax might be good places to start. --David Iberri (talk) 05:13, 23 February 2006 (UTC)

Wormholes- time machines???[edit]

I am not even sure whether wormholes even exist. Please clarify. Also, what i have read from your article on wormholes, that one can travel from one part of the universe to another. So basically, it is like a time-machine. What i want to know is where and how far is the closest wormhole to earth and whether there's any possibility of sending a satellite to it or something. Also can we know before entering a wormhole, how long are we gonna go back in time or in future?

At the moment, wormholes are a theoretical possibility - in other words, they have proven to be perfectly consistent with the current theories of the universe, but no-one's ever found one. And, to my knowledge, the only way of knowing the details of a wormhole's path in space-time require you to either experience it yourself or control how it's formed (although if you find some light passing through it there might be some hints there). Confusing Manifestation 12:20, 21 February 2006 (UTC)
There are two types of wormholes used in science fiction. One allows you to travel anywhere in the universe instantaneously. It is not time travel because you do not arrive at the new location in a different time. You arrive there in the present - but you do get there much faster than someone travelling at the speed of light and taking, possibly, thousands of years. Another wormhole is one that punches through time instead of space. You travel forward/backwards in time, but stay in the same location. Such a wormhole has not been proven to be consistent with current theories of the universe.
A sanity check about time machines that can travel into the past - if they existed, why don't we have them? Any rationalization for us not having them is so flawed that it is more likely that the existence of one would cause it to exist backwards through all time - which would also revert technology to the beginning of mankind. So, it is logically sound to claim that nobody is ever travelling from our future to our present. --Kainaw (talk) 18:01, 21 February 2006 (UTC)
Er, what are you claiming exactly? Time travel brings with it a host of theoretical and practical problems, but I don't follow your arguments. What do you mean why don't we have time machines if they exist? Perhaps those who have them are too far away from Earth or are unaware of Earth's existence, or have no desire to visit Earth. If humans develop them in the future, there are several reasons why we wouldn't be aware of their existence today. It could be that, aware of the significant damage they could do to the timeline, travel to Earth's past is prohibited, or perhaps done under secrecy so the natives (us) won't realize that there are time travellers among us (sort of a temporal Prime Directive). If it's a wormhole, the terminus could be so far from Earth as to make travel to it quite difficult. Perhaps people have travelled back through time and have significantly affected the timeline; time in those universes would proceed in a different manner, and we may be inhabiting the original "unpolluted" timeline. Perhaps time machines exist but require so much energy to use that only small amounts of matter can be transmitted. There are countless possibilities; one cannot simply dismiss them in such a casual manner. I should note that I perosnally am undecided/skeptical about the theoretical possibilities of time travel (though it makes for great science fiction), but my mind remains open. — Knowledge Seeker 20:11, 21 February 2006 (UTC)
Let me clarify: Humans (us) will not create time machines in our future that will allow us to travel to our present or our past here on this planet. It may be possible for one to exist in the distant future that can travel to the nearer future, but not to the present. This does not limit time travel by other lifeforms or time travel to distant locations in space. Even in science fiction, the time cops can't keep guys from travelling into the past just for fun. There is also the situation of stealing the invention. I invent it. You travel back to last year and claim you invented. Someone else travels back a year before that and claims they invented it. Not just time machines - but everything falls victim to this scenario with time machines. So, because humans are inherently greedy, everything will have been invented in our past, not our future. But, there may still be a day in our future where time machines appear and everything is invented on that day. --Kainaw (talk) 20:31, 21 February 2006 (UTC)
That is at least partially true, because most workable theories of time travel require that you can't travel back further than when the "time machine" was invented. However, what you said before about there being two types of wormholes is not, to my knowledge, correct. Instead, there is one type of wormhole that links two points in spacetime by a smaller distance than the normal spatial distance (so it might, for example, connect a point in the Milky Way with a point in the Andromeda galaxy, but be only a mile long internally). Then, let's say you can move one end of the wormhole around like a physical object. Bring it in close to the other end, and the fact that it's been travelling means that it experiences time dilation, so that now there's a time difference between the two ends, and, again by my understanding, you can draw a path that goes through the wormhole and ends up at the same point in space, but at a previous point in time. Hence the space wormhole becomes a time machine. Confusing Manifestation 04:10, 22 February 2006 (UTC)

One suggestion was that super massive black holes exist at the center of each galaxy which would be suitable as wormholes. So, what's the distance to the center of the Milky Way ? StuRat 21:33, 21 February 2006 (UTC)

While I am not a physicist, it is my understanding that while wormholes theoretically exist, there are serious problems with 'using' them. As far as I understand it, wormholes like Einstein-Rosen Bridges collapse as soon as any matter travels through them, and to keep them 'open' you would need to have some really exotic matter, as it needs to have negative mass and negative gravity.
Also, wormholes tear 'holes' in space-time, which could be seen as an extension of black holes (which merely dent spacetime so much that light can't get out once it's gone in) - so entering a wormhole would subject you to immense gravitational stretching (turning you into spaghetti), plus there's the problem of your local time slowing down as you approach the event horizon, and coming to a complete halt the moment you cross it. What about getting out the other end? You effectively come out of a black hole - a rather difficult proposition, I'm sure you'll agree :)
Again, I should stress this is mostly theoretical at the moment, as no-one has ever observed a wormhole, and advances in theoretical physics might, in future, provide for wormholes which are slightly more useful. However, until then, the prospects for wormholes looks dicey at best. — QuantumEleven | (talk) 14:21, 22 February 2006 (UTC)
Addendum to StuRat: the distance to the centre of the Milky Way is about 26000 lightyears. See Milky Way.

Nothing would please me more than to find out one day that the total entropy of the universe decreases when one attempts to time travel. --HappyCamper 11:38, 23 February 2006 (UTC)
LOL -- 05:10, 24 February 2006 (UTC)


Can anyone show me the picture of "antimatter" and "exotic particles"? Or please provide links where i can find them.

I think you may find that, because these are usually made in quantities of a few particles, and often travelling at the speed of light, that these cannot be photographed. The closest you get is photos that show where they have been. On the other hand if you did have something made out of anti-matter and stored in a perfect vacuum, it would look exactly like the same thing made out of matter, so any photo would do. Notinasnaid 13:51, 21 February 2006 (UTC)
This is what's available. WAS 4.250 17:31, 22 February 2006 (UTC)
Wooohoo! Antimatter is a happy bunny waving hello! What a wondereful universe we live in. Ferkelparade π 12:07, 23 February 2006 (UTC)
Hahaha! Oh man, that was great! ? ?i?ff?? 02:45, 25 February 2006 (UTC)

Online telescopes.[edit]

Can anyone tell me a site where i can find access to online telescopes through internet? Thank you.

Where can i find free online telescopes excluding The Bradford Robotic Telescope?

Strange Diffusion[edit]

chlorine gas in a container is put below air in another container, both separated from each other by a lid. Why does the chlorine diffuse with air even though it is denser than air??? --Nitin.1704

If they are seperated by a lid, the Chlorine will stay where it is unless the lid is porous.

If gases always separated according to their densities, all the oxygen in Earth's atmosphere would sink to the bottom and all the nitrogen would rise to the top. The answer has to do with the competition between minimizing energy and maximizing entropy. —Keenan Pepper 18:14, 21 February 2006 (UTC)
It's all about the concentration gradient for the gases, which in this case is a greater impetus to diffuse than gravity. Alarmingly, concentration gradient was a redlink, so I've redirected it to diffusion. See also passive transport. Proto||type 12:35, 22 February 2006 (UTC)

I forgot to tell that the lid is opened bfore all this happens --Nitin.1704

Yes, and the subsequent diffusion is due to the concentration gradient. Proto||type 15:34, 22 February 2006 (UTC)

Crust composition of the moon[edit]

In the article moon there is a table which gives the crust composition in percent but doesn't mention if it is in percent of mass or in percent of atoms. Which is it? The Infidel 19:17, 21 February 2006 (UTC)

With all these things (like ingedients), it's percent by weight. --Zeizmic 21:42, 21 February 2006 (UTC)
Is that a geological tendancy? I did a quick check and while units like ppm can be by weight, they're more often by mol. Also, ~40% oxygen would seem far more likely to be a molar, rather than mass-based, measurement. — Lomn Talk 22:02, 21 February 2006 (UTC)

I think that's a deficiency in the article. Elemental percentages might be some astronomical convention that I don't know about. When I look at other articles [22] they specifically state 'wt.%' of Fe0, etc. This is the usual convention with minerals. --Zeizmic 22:15, 21 February 2006 (UTC)

So that is quite like it looks to me: generally those compositions (on earth!) are measured by wight, but ometimes in mol. When elements are recognized by spectroscopy or calculated from nuclear processed, it's probably mol, not weight, unless the numbers are converted to match the supposed usual measure. All in all, we don't know for sure.
The table was added on long ago by an anon user ( so we can't even ask what the source was.
Now what is to be done in such a case? The Infidel 18:05, 22 February 2006 (UTC)

5th grader[edit]

Is audio or visual information better remembered? Looking for suugestions for websites where info can be found on said topic. Aslo need ideas for a graphic presentation to show said question. Thanks

It really depends on the person - find out what is best for you. Lots of people are visual learners though, I think. Some educational models suggest using a mixture of approaches is best - visual (learning by seeing), audio (learning by listening), kinesthetic (learning by doing). In my lectures/lesson plans, I try to do what generally works well for the class, and also what works best for the topic. For example, for composition theory, I tend to bring recordings to the class, and turn off the lights so everyone can hear what is important. For geometry, I might resort to a visual approach. Generally, "what makes sense the best" works well. --HappyCamper 22:21, 21 February 2006 (UTC)

Wow, has this got to be a common school question! I just googilized and got this [23] --Zeizmic 22:31, 21 February 2006 (UTC)

  • If this refers to the other 5th grader questions above, I would recommend a mix, though I would expect a majority of your fellow students would prefer visual information. - Mgm|(talk) 09:51, 22 February 2006 (UTC)
  • By any chance, is this question, related at all to this one? Or do 5th graders just tend to gravitate towards wikipedia in unusually large numbers?-- 05:09, 24 February 2006 (UTC)