Revision as of 02:05, 13 September 2006

Reference Desk

September 6

Ejaculation

Is there any way of shortening the "refill time" after I've ejaculated semen from my penis? Do any of those pills you see advertised on the internet that claim they do this really work?

The "refilling time" you refer to is called a refractory period Raul654 00:30, 6 September 2006 (UTC)

Also, from that article, The refractory period varies widely between individuals, ranging from minutes to hours. An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the refractory period and the amount by which oxytocin is increased may affect the length of each refractory period. Another chemical which is considered to be responsible for this effect is prolactin, which represses dopamine, which is responsible for sexual arousal. So I suppose any enzyme that breaks down either prolactin or oxytocin could theoretically decrease the time of a sexual refractory period. Raul654 00:32, 6 September 2006 (UTC)

Perhaps training yourself to need less time will work. --Proficient 04:12, 6 September 2006 (UTC)

What sort of training did you have in mind?--Light current 18:00, 6 September 2006 (UTC)

I consider myself an expert in the field and would definetely recommend "milking" which would induce your body to keep up with the demand. - Tutmosis 01:26, 7 September 2006 (UTC)

Can you eleaborate?--Light current 14:31, 7 September 2006 (UTC)

Its very simple, milking is forced (A.K.A planned & executed) masturbation a number of times a day to force your body to increase sperm production as well as the rate. Years of training will give you results so great that you will even forget what being "dry" means. - Tutmosis 00:36, 8 September 2006 (UTC)

OK thats assuming you can do it more than once a day. You must be a youngster! Enjoy it whilst you can! 8-)--Light current 00:38, 8 September 2006 (UTC)

I have to admit I dont have the swing I used to have but I'm sure with hard work and devotion we can all "spray the goodness" again. - Tutmosis 00:48, 8 September 2006 (UTC)

o_o --Froth 20:27, 8 September 2006 (UTC)

TMI Raul654 20:35, 8 September 2006 (UTC)

AS long as youre not doing it whilst editing, I can deal with that! 8-)--Light current 00:50, 8 September 2006 (UTC)

Sticky keys ? :-) StuRat 13:48, 12 September 2006 (UTC)

THats OITE for WP!--Light current 15:43, 12 September 2006 (UTC)

Mouthwash, alcohol, toxicity, &c.

I hold in my hand a travel bottle of Scope® mouthwash, a generous, easily-confiscatable gift from the good people at Continental Airlines. In the air, I wondered out loud whether one could obtain more alcohol from the bottle of Scope than from the little bottles of wine they were giving out. I also secretly suspected the Scope would be less sweet. I was thinking of the old comedy trope of the high school kid getting wasted on Listerine or the Vietnam veteran hooked on cough syrup. But, as I discovered a minute later, the label advises any unlucky ingester to contact a poison control center immediately. This Scope contains 15% alcohol by volume, as well as water, glycerin, "flavor", polysorbate 80, sodium saccharin, sodium benzoate, cetylpyridinium chloride, benzoic acid, blue 1, and yellow 5. Presumably cetylpyridinium chloride is the toxin, but in what concentration does it pose a threat to the human body? I remember, as young children, my brother and I unwittingly drank brimming Dixie cups of the stuff, not realizing the idea was to spit it out. Nor can I recall suffering any ill effects. I ask someone with a knowledge of chemistry: Is the Listerine lush an inaccurate or outdated trope (perhaps due to an advance in mouthwash technology), or alternatively, has the toxicity of mouthwash been exaggerated, perhaps to prevent lawsuits and substance abuse? Bhumiya (said/done) 04:59, 6 September 2006 (UTC)

Here's what Straight Dope says: -- Scientizzle 05:19, 6 September 2006 (UTC)

Interesting. Thanks for the quick response. Bhumiya (said/done) 05:30, 6 September 2006 (UTC)

And wow, who would ever think of replacing mouth wash with pure vodka with a little food coloring???

I'm surprised that nobody has mentioned that there are two kinds of alcohol, and that the industrial cheaper kind is POISONOUS and will send you blind. I have often heard on the BBC news of people in India and elsewhere who drank cheap alcohol without being aware it was the industrial kind and went blind. The industrial kind is also that found in chemistry labs. It may also be the alcohol in mouth washes - so I wouldnt drink it. The two types of alcohol do have different names but I cannot reliably tell you what they are. 81.104.12.107 20:19, 10 September 2006 (UTC)

methanol is the industrial alcohol and ethanol is the alcohol found in drinks

Genetic Gender

Why do some couples have say three girls, whilst other have three boys? Is this just the luck of the draw, or is there something else going on, like a genetic leaning toward having children of a certain sex?

See Sex ratio, Sex-determination system and XY sex-determination system for the genetics behind it. It's essentially the luck of the draw, as I understand it. --Robert Merkel 09:14, 6 September 2006 (UTC)

Statistics is one of the least understood things (alas, because a good understanding of it is essential to understanding the world around you). Having 10 children of the same gender sounds so unlikely that the couple that had them would probably think there was something special going on. But the chances are 1 in 512, which makes it likely that once in a while it will happen (if there are enough cuples that have 10 kids, that is). But then people will think that the fact that it happened to them specifically is significant. It isn't. No-one would think anything of having 3 boys and 7 girls in a specific order, but he chances are exactly the same. DirkvdM 09:52, 6 September 2006 (UTC)

"The chances are exactly the same" — that's true, but when most people say that MMMMMM looks more un-random than MFFMFM, they usually mean something more akin to "the odds of getting a non-homegenous pattern are much higher than getting a homogenous one", which is true. Unfortunately I doubt most people know that's what they're actually referring to when they say the first sequence looks more significant than the latter. It's the same thing as when statisticians deride people for choosing 010010 as the "more random" sequence than 000000; if each element is independently determined, then any single outcome is as likely as another, but if one is instead taking a more intuitive, "homogenous/nonhomogenous" approach then indeed, you'd expect more truly randomly generated sequences to "look like" the first one than the second. --Fastfission 18:14, 6 September 2006 (UTC)

I remember hearing that certain conditions could lead to men having more girls than boys. I think it was high levels of testosterone, which can also lead to early baldness. I don't have a source for this though, but I'm sure Karl Kruszelnicki mentioned the link once. If anyone has better info it'd be appreciated. I should probably check the articles mentioned too. —Pengo 11:47, 6 September 2006 (UTC)

The sex ratio article links to a couple articles about research that indicate that men infected with Hepatitis B have more male children. There was also some recent press about a study that showed that attractive people were more likely to have female children and some articles mentioned previous studies by Satoshi Kanazawa that showed that scientists, mathematicians engineers, big or tall parents and violent fathers are all more likely to have sons than daughters. It seems pretty certain to me that all couples do not have the exact same 50-50 chance of boy and girl children. -- Plutortalkcontribs 13:02, 6 September 2006 (UTC)

It's not a 50-50 chance, even on the average. More boys are born than girls. --Trovatore 21:10, 6 September 2006 (UTC)

Note however, that the the ratio of sexes born need not be the same as the ratio of sexes conceived. The sex of a foetus will be determined at conception, however, during the 9 months in utero, there could well be differences in survival rates between sexes. There could also be genetic predispositions to bearing children of one sex over the other, theoretically at least. For example, consider a mother who has an allele on one of the X-chromosomes that, when hemizygous would cause early embryonic lethality by haploinsufficiency (lets ignore the problems that Lyonisation would cause her or her female children, for the moment). All else being equal, every child born to her would have a 1/3 probability of being male, rather than a 1/2. However, the probability of her conceiving a child of either sex remains 1/2, respectively. I am not familiar with an exact gene that this model would fit this example, but i'll wager it happens. Thus having multiple children of the same sex is most often simply due to chance, but i would argue that a specific genetic predispositions cannot be ruled out. Rockpocket 01:12, 7 September 2006 (UTC)

I think you're wrong about the probability of conception for either sex being 1/2. If I recall correctly, male fetuses are more likely to die before birth, so the disparity at time of conception must be even larger than the disparity at time of birth. Of course, that could be rolled into your "other things being equal", but my point is that other things are not equal. --Trovatore 03:50, 7 September 2006 (UTC)

Possibly true. However, the problem with the data you mention, is that it is based on later-pregnancy miscarriages. As much as 50% of all conceptions fail: its thought that around 1/4 of fertilized eggs fail to implant in the uterine wall and 1/3 are spontaneously aborted within the first six weeks after conception, both without the mother ever knowing she is pregnant. Since we have no idea of the sex ratio of these failures, the impact of the (relatively speaking) small number of later-stage male-biased miscarriages could be negligible. If these early failures balanced up the sex bias, your logic would fail. My assumption of equality was to demonstrate my theoretical point on the difference between conception/birth ratios in a simplified model. The fact is, we simply don't know if "other things are equal", as we don't have a full data set. Rockpocket 05:40, 7 September 2006 (UTC)

I think that's a stretch, frankly. The ratio of Y-carrying androsperm to X-carrying gynosperm is known, and the ratios of later fetuses is known, and both (unless I'm misinformed) support the idea that there are more male conceptions. I think you're overapplying the notoriously shaky principle of indifference. --Trovatore 07:33, 7 September 2006 (UTC)

I completely agree. Per Occam's razor, that certainly is the post parsimonious explanation. However, the possibility remains, however remote... Rockpocket 18:20, 7 September 2006 (UTC)

Sleep

Why do I get a headache if I'm fortunate enough to get too much sleep? And is this a common reaction to sleeping too much? Dismas| 10:32, 6 September 2006 (UTC)

It's a known phenomenon. This article discusses a possible mechanism. --Lambiam 10:49, 6 September 2006 (UTC)

How much is too much, because I can't say I've ever had a headache from this. --liquidGhoul 11:00, 6 September 2006 (UTC)

I find it usually happens when I go to sleep again, i.e. when I half-wake up, decide that I don't want to get up at this time today, and wake up again a few hours later with a headache.  freshofftheufoΓΛĿЌ  14:03, 7 September 2006 (UTC)

Actually that article doesn't say much. It can be many things, including but not limited to:

1. Musculoskeletal discomfort due to prolonged immobility, imperfect bedding, or uncomfortable position;
2. Overheating;
3. Mild dehydration;
4. Low blood sugar;
5. Caffeine withdrawal;
6. Low blood pressure;
7. Poor sinus drainage (exacerbated by being prone);
8. Sleep apnea. Oxygen deprivation causes headaches, and the longer you're experiencing it, the worse a headache you'll get.

--Anchoress 11:09, 6 September 2006 (UTC)

Sn1&Sn2 Reactions

please tell me about following things in sn1 & sn2 reactions

1.Nature of substract
2.Nature of attacking nueclophile
3.Nature of leaving ion
4.Nature of solvent

It would probably be best if you look at SN1 reaction and SN2 reaction then come back with any specific questions you still have.--Ed (Edgar181) 13:59, 6 September 2006 (UTC)

A car for $1

What would you do if you see an ad like this:

• Offer for sale of EXACTLY ONE $30,000 car for $1.
• First come first served.
• However, you're required to throw a die:
  • If the 1st one in line gets a "1"; he/she takes the car home.
  • If the 2nd one in line gets a "1" or "2"; he/she takes the car home.
  • If the 3rd one in line gets a "1", "2" or "3"; he/she takes the car home. ...
  • Whatever 6th one in line gets; he/she takes the car home if all previous five did not make it.

If you want that car, what is your strategy to maximize your likelihood of winning? -- Toytoy 13:59, 6 September 2006 (UTC)

Just work out the probabilities. The first guy has a 1/6 chance of winning a roll, and a guaranteed chance to roll. The next has a 2/6 chance of winning if he rolls, but only a 5/6 chance of getting to roll. The calculations proceed thusly. — Lomn | Talk 14:17, 6 September 2006 (UTC)

I should note: a more interesting question is "what is a fair price for the chance to win the car?" Obviously the seller can't recoup his $30000 with $1 tickets, but if the tickets are only bought when the die is rolled (rather than in advance), what should he charge to average $30000 worth of tickets sold? — Lomn | Talk 14:21, 6 September 2006 (UTC)

Require 100 sided dice, then be last in line.

Hire some gorillas to prevent anyone else from queueing. So long as the hired help costs less than $29,994, you'll walk away smiling. --Dweller 14:28, 6 September 2006 (UTC)

Go 2nd or 3rd, it doesn't matter which.

- Nunh-huh 20:26, 6 September 2006 (UTC)

It might be an intersting game theory problem if you had a group of 6 people who each had to volunteer to go first, second, third etc. You'd have to set up the mechanism for volunteering in some specific way, but it might be interesting. --best, kevin 21:43, 6 September 2006 (UTC)

If I saw this ad, and was able to determine it was not a marketing promotion, I would ignore it as a probable scam of some type, simply because common sense says that reasonable people don't just give away expensive cars. --Ginkgo100 21:50, 6 September 2006 (UTC)

Yea, like you may only be able to get the car for $1 if you agree to pay $40,000 for the car keys. :-) StuRat 23:35, 6 September 2006 (UTC)

If the car is legally yours, I'm pretty sure you could get new keys made (or the locks replaced) for less than $40,000. (In fact, you could probably get new keys to a car for less than $40,000 even if it wasn't legally yours, but that could cause other kinds of problems further down the line...) —Ilmari Karonen (talk) 01:26, 7 September 2006 (UTC)

I'm saying that the car wouldn't be legally yours (they wouldn't sign over the title) until you bought the $40,000 key, hence the trick. StuRat 06:36, 7 September 2006 (UTC)

I actually saw an ad once for a hideously expensive bicycle, that cost like a car, and you got a car with it. :-) —Bromskloss 13:54, 7 September 2006 (UTC)

BTW, this question should have been posted to the Math Ref Desk. StuRat 23:37, 6 September 2006 (UTC)

I'd buy all six tickets for $1 each, that's still just $6 for a $30000 car. – b_jonas 08:53, 7 September 2006 (UTC)

That answer sounds strangely familiar. --Dweller 09:40, 7 September 2006 (UTC)

yDNA Mutation Rates

What are the relative Mutation Rates of yDNA STR's used in Genetic Genealogy?......... Cymri

there are no good reliable published figures for those differential rates. The closest you'll get is a statement that a given STR is a "slow" (or "fast") mutater. - Nunh-huh 20:02, 6 September 2006 (UTC)

Ok Can anyone list the "fast" and "slow" Loci? or perhaps provide a limk to such information. cymri

Recognize this optimization problem?

I need to find a search algorithm for the following optimization problem. We are given ${\displaystyle N}$ (smallish) finite sets ${\displaystyle A_{k}}$, and we are to choose one element from each, to yield a multiset ${\displaystyle B}$ of size ${\displaystyle N}$. We are also given a finite mapping ${\displaystyle \omega }$ from multisets to real-valued weights, and we are to maximize the sum of the weights associated with the submultisets of ${\displaystyle B}$, ${\displaystyle \sum _{C\subseteq B}\omega _{C}}$.

If we constrain the domain of ${\displaystyle \omega }$ to multisets of size ${\displaystyle 1}$, we can choose from each ${\displaystyle A_{k}}$ independently, and the problem is trivial.

If necessary, I can afford to constrain the domain of ${\displaystyle \omega }$ to multisets of size ${\displaystyle 2}$, but I'm beginning to suspect that this is already NP-complete.

If it is NP-complete then I would appreciate any advice on approximations or reductions to other problems for which good solvers are available. Can I do better than the obvious reductions to ILP or weighted MAX-SAT?

Thanks and best wishes 128.220.220.95 19:20, 6 September 2006 (UTC)

I suggest you move this to the Mathematics reference desk. --Lambiam 23:02, 6 September 2006 (UTC)

Good point. I will start there next time. 128.220.220.95 17:00, 8 September 2006 (UTC)

If we allow ${\displaystyle \omega _{C}\not =0\;\forall \left|C\right|\leq 3}$, this problem would solve boolean satisfiability (in particular 3SAT), as you hinted with MAX-SAT. Consider ${\displaystyle A_{k}=\{(k,0),(k,1)\}}$; then, for each value ${\displaystyle (k,i)}$ in a disjunction (that is, ${\displaystyle (k,0)}$ if ${\displaystyle \lnot x_{k}}$ appears, and ${\displaystyle (k,1)}$ if ${\displaystyle x_{k}}$ appears), increment ${\displaystyle \omega _{\{(k,i)\}}}$. Then undo the double counting (where ${\displaystyle (\lnot )x_{k}}$ and ${\displaystyle (\lnot )x_{k'}}$ succeed in a term containing both anyway) by decrementing ${\displaystyle \omega _{\{(k,i),(k',i')\}}}$ for each pair of literals that appear in the same disjunction. Then repair three successes minus three handshakes by incrementing ${\displaystyle \omega _{\{(k,i),(k',i'),(k'',i'')\}}}$. Then maximize, and see if the result has value equal to the number of disjunctions (this can be done in polynomial time because there are no more than ${\displaystyle {N \choose 1}+{N \choose 2}+{N \choose 3}\in O(N^{3})}$ non-zero values of ${\displaystyle \omega _{C}}$). This reduction typically involves negative weights, which you might not have had in mind, but I imagine that it could be recast without them. Obviously the corresponding argument with ${\displaystyle \left|C\right|\leq 2}$ fails because it's 2SAT then, so I'm afraid I don't have any truly useful answer at the moment. Hope this helps. --Tardis 23:20, 6 September 2006 (UTC)

Very cool, and I believe I've just learned something from the 2-satisfiability article that allows me to finish your argument: 2-SAT can be done in polynomial time, but MAX-2-SAT is NP-complete. It looks like I'm back to the drawing board, so thanks for helping me figure that out sooner rather than later. 128.220.220.95 17:00, 8 September 2006 (UTC)

Dogs and people

I know that any answer to this question must remain as speculation: What do dogs think humans are? They must not think of us as fellow dogs, because we probably smell different, and they do not try to mate with us. Are they usually submissive because we appear to be much larger members of some other species? Does Misplaced Pages have any articles on this subject? Pete

There is a lot of debate over exactly how dog/human relations are or ought to be (i.e. does the human master represent the alpha pack member?), but I think one can say somewhat safely that most animals are not able to get into the sorts of relationships that dogs have with humans (even cats seem to have difficulty tolerating humans a lot of the time, much less non-pet animals), and it is precisely this character trait which has made dogs "man's best friend" as they say. For whatever reason they seem to be able to adapt to co-habilitation with humans very well, and many dogs seem to exhibit symptoms of real affection for their human owners (one can always wonder if it is a trick, but I'm pretty sure my dog likes me—she goes way above and beyond what would be necessary to get food and attention). Of course dog behavior towards humans can vary a lot with breed—some breeds are notoriously independent and stubborn, some are very easy to train, some are known to be very friendly towards people, and some are known for their ability to be quite violent to humans. Unfortunately we don't seem to have a lot on this (our Behavior subsection of the "Dog" article is really, really short). We have a short article on Companion dogs but it doesn't have much on dog psychology. --Fastfission 20:31, 6 September 2006 (UTC)

I'm not sure its proper to attribute the sort of cognitive abilities to dogs that allow them to classify us. Perhaps dogs don't classify animals in their environments in the same way humans do. It might not "occur" to a dog to ever think about what we are. I don't know much about research into animal cognition, but I'm not sure if there is any reason to think they classify their environment into species. --best, kevin 21:40, 6 September 2006 (UTC)

Just a couple of things to add. Many dogs actually do try to "mate" with us, or at least our legs. As for being submissive to larger creatures, it may be counterintuitive but the truth is that the larger the dog, the more gentle and submissive it is. It tends to be those tiny rat-dogs, the Chihuahuas, the Toy Poodles etc. that tend to be the nastiest and the most anti-social towards many humans. Have you ever been growled or been given dirty looks by a giant St. Bernard or Golden Retriever? Loomis 21:47, 6 September 2006 (UTC)

I took care of a toy poodle (absolutely tiny) for a neighbor for a few days. He didn't seem to like me much, especially if he was on the ground and I was upright. He also tried to kill the vaccuum. However he was very mellow around most members of the household, he was usually very happy to just sit with/on you. Perhaps he was unusually well-trained, but he adapted very quickly to the change. 206.124.138.153 05:42, 9 September 2006 (UTC)

Based on my (limited) observations of dogs, individual dogs behave in a somewhat consistently different way with respect to members of different species: they don't greet cats like they greet dogs, and a dog that chases one unknown cat tends to chase them all. Yet the same dog will not chase humans, only bark at them. To the extent that it is reasonable to apply human labelling to what dogs "think", my best guess is that dogs think that dogs are dogs, cats are cats, and humans are humans. --Lambiam 23:12, 6 September 2006 (UTC)

We do have two relevant articles -- Animal cognition and Dog intelligence. --Halcatalyst 23:21, 6 September 2006 (UTC)

I go with dogs viewing their owner as the pack leader/alpha dog, whereas cats view their owner as their mother (even male owners). StuRat 23:20, 6 September 2006 (UTC)

This article from the NYT has something about the problems created by framing the interaction with your dog in the alpha dog theory. Dogs are not wolves, but also for a pack of wolves the social structure is not like that of a troop of chimps. --Lambiam 04:09, 7 September 2006 (UTC)

I believe that dogs and wolves are, in fact, one species. This means they can mate and produce fertile offspring. StuRat 02:05, 9 September 2006 (UTC)

Supporting that thought... the best way to completely immobilize a cat is to pick it up by the scruff of its neck, like the mother cat does. --Halcatalyst 23:23, 6 September 2006 (UTC)

The immobilization reflex is mechanical and has nothing to do with how the cat views us. --Lambiam 04:09, 7 September 2006 (UTC)

Behaviourists from John B. Watson to B.F. Skinner saw no need to postulate what animals or people thought. Instead they saw our actions as the result of behavioural conditioning. The question of what a dog thinks a person is would be as meaningless as the question of what a person thinks a dog is (toy? child substitute?). They might note behaviours such as a cat kneading the owner stomach as learned from the utility of that conditioned response in obtaining milk from the mother. Cognitive psychologists theorize about internal mental states and how they control behaviour.

Many dog owners would say that dogs seem to think they and people are not that different, whether it be two kinds of dog or two kinds of people. Edison 23:40, 6 September 2006 (UTC)

Hmm. Sounds like a classical case of psychological projection to me. --Lambiam 04:13, 7 September 2006 (UTC)

I thought if the dogs were bigger, the more agressive and less social they were. ._. --Proficient 04:18, 7 September 2006 (UTC)

St. Bernards are quite large, but they're highly social as well as gentle. Behavioural traits aren't necessarily tied to the size at all; I've seen small dogs that are insanely aggressive. -- Consumed Crustacean (talk) 04:25, 7 September 2006 (UTC)

I believe the counterintuitive result that small dogs are more aggressive is due to artificial selection. While an aggressive small dog is considered by some to be acceptable, or even cute, an aggressive large dog is seen as dangerous. Thus, aggressive large dogs were less wanted and less likely to be bred than aggressive small dogs. After a few thousand generations, this leads to a lack of aggressive, large dog breeds. StuRat 04:29, 7 September 2006 (UTC)

That is entirely possible. Behaviour doesn't occur in a vacuum, however, and another factor is fear. Most animals will display aggressive behaviour when they feel threatened or harrassed - the fight part of fight or flight. The size of a dog in relation to the threatening cue is a factor in where they feel threatened or not, hence small dogs may be more likely to be aggressive than large ones, simply because they are more afraid. Genetics play a role in this too, of course. Note that we have bred larger dogs to be working dogs. Having them afraid of, or aggressive with, humans is not an ideal characteristic for their function. So that has been selected against. On the other hand, small show dogs are bred for how they look, so their fear of humans (as StuRat suggests) is inconsequential for their function. Rockpocket 06:00, 7 September 2006 (UTC)

William Gray (Meteorologist)

I have searched all over the internet for some background information on William Gray the hurricane forecastor and am unable to find out his birth date, where he was born and general information on his childhood. I did find ample information on the work he has done in hurricane forecasting but would be very gratefull if someone could help me on his background.

regards,

mactennis.

A recent article says he's 76. That narrows his birth down, so you can try more searches to pinpoint it. Melchoir 21:06, 6 September 2006 (UTC)

Trying to get glasses

Three years ago I failed my school's eye exam and since then I have been to the eye doctor three times. Each time, the doctor told me that I was really close to needing glasses but my perscription is so small it would not even be worth it. Is there anything I can do to tip the scales in favor of requiring glasses within the year? Advice would be appreciated.

Usually I respond to people who are honest. Just say - "it may be a small correction, but it really means a lot to me. Could you please prescribe me glasses so I can use them when I feel I need to?" If they will not sell you glasses, ask for your refractive error. If all else fails, see a different doctor! InvictaHOG 01:28, 7 September 2006 (UTC)

Watch television up close, read in the dark, and neglect your carrot consumption. Staring at wikipedia pages all day will probably help too. AEuSoes1 02:20, 7 September 2006 (UTC)

I think I once read that reading in the dark doesn't hurt your eyesight, but that might have been a myth. --Proficient 04:20, 7 September 2006 (UTC)

Yeah, I don't see how it would. Carrots also don't help with eyesight. I was being facetiously misleading. AEuSoes1 05:31, 7 September 2006 (UTC)

How often do you masturbate, any room for improvement? Some people continue to believe that "self abuse" leads to deterioration of eyesight. That is almost universally dismissed by doctors as untrue, of course, but what have you got to lose ;)? In all seriousness, it is inadvisable to try any technique to make your eyesight worse. Anything the might work would also run the risk of damaging your eyes. Your optometrist is most likely delaying the inevitable out of a misplaced concern that you might not wish to have specs. as InvictaHOG suggested, I would recommend explaining honestly and firmly that you would like to have your vision corrected and would appreciate if they could do that for you. If they can't, take your future business elsewhere. Rockpocket 06:44, 7 September 2006 (UTC)

You obviously think you need glasses, but why? If you are having difficulty in reading small print, pick up some cheap reading glasses at a drug store/chemist.--Shantavira 07:16, 7 September 2006 (UTC)

• The doctor said the prescription was too small to require correction. Have you ever asked him what the values where. If it was anything up to 0.5 of correction, he is probably correct about you not needing correction. By the way, the fact you go to the eye doctor once a year (or at least three times in three years) is something you should continue. Having your eyes checked should be something as regular as having your teeth checked. - Mgm| 07:28, 7 September 2006 (UTC)

I was like this, aged about 10. I thought that wearing glasses would improve my appearance(!) (Sigh) I even pretended in sight examinations that I couldn't read very small letters on the sight chart that I actually could read. I was therefore prescribed glasses of the wrong prescription, before I needed them. I've been wearing glasses ever since and now can't cope without them. The deterioration of my sight is probably mostly down to nature, but in an ignorant lay manner, my gut instinct is to attribute some of the blame to this stupid behaviour. So, my advice (as an ignorant lay person)?

• 1. Don't contemplate pretending your sight is worse than it is
  2. Avoid wearing prescription lenses for as long as you can, within the sensible advice of your optometrist
  3. Don't pick up "cheap reading glasses" that haven't been prescribed for you if you're young enough that "three years ago" you were still at school
  4. Glasses don't make you look clever or glamorous or alluring or mysterious. If you're tempted, think Clark Kent v Superman.
  5. Don't do stupid things that you'll regret later in life.heck, that's what being young is all about, isn't it? Anyway, I ain't young and I do really stupid things all the time--Dweller 10:00, 7 September 2006 (UTC)

Or just buy glasses that have no refraction index?  freshofftheufoΓΛĿЌ  13:52, 7 September 2006 (UTC)

Im puzzled that the school eye exam says you need glasses when a professional optometrist says you dont. I know whom I would believe (the pro)--Light current 14:48, 7 September 2006 (UTC)

For me the only real "pro" is the patient. If you have trouble seeing, you need glasses. It doesn't matter how "weak" your prescription would be. I wear glasses with such a weak prescription (-.50 left, -.75 right) that when my friends try them on for fun they just look like clear glass to them and they find it hard to understand what I need them for. Yet for me the difference is HUGE. Without them everything is fuzzy and with them everything is crystal clear.

As for buying cheap glasses at a drugstore, there are a whole bunch of reasons not to, but by far one of the most important is the fact that these places only tend to sell glasses to correct for presbyopia or "far-sightedness". Since I'm assuming you're rather young (being in school and all), I'm assuming that like me, you've got the opposite: myopia or "near-sightedness". Presbyopia tends to happen to practically everybody as they age. When older people start to have trouble reading small print, they get reading glasses. These are the types that are sold in drugstores. They always have "plus" prescriptions (as in +1, +2, +2.5 etc...designed for presbyopia) and also, they always assume both eyes are in equal condition. You'll never find a pair that are, for example, +2 right, +3 left. My guess is that you're like me and you're not presbyopic at all, but rather slightly myopic. That means that your glasses would have to have a "minus" prescription. It's easy to tell the difference. If you don't have any trouble with "up-close" things like reading, but have a lot of trouble seeing things that are further away, like the tv or or the blackboard or recognizing a friend from across the street, that means you're myopic, and besides being bad for you, those drugstore glasses wouldn't even be of any help...if you wore them they'd probably make things even fuzzier.

In any case, go to your eye doctor, and just be firm about it. Tell him or her that you can't see well, (and, if true, throwing in a bit about how you have trouble reading the blackboard would definitely help, nobody wants to have students who can't read the blackboard because they have a stupid doctor!) and that you NEED glasses. If s/he doesn't cooperate, see another doctor. If that doesn't work, talk to the folks at school where you failed the eye tests, I'm sure they'd be a lot more sympathetic. Good luck! Loomis 23:28, 8 September 2006 (UTC)

OK Let me put this another way. Why is there such a difference in the school eye exam and the optometrists results? Can this minor correction really be necessary for children, when it obviously isnt for adults?--Light current 18:03, 9 September 2006 (UTC)

When I was 10 years old, I was told I'd need glasses when I came to start driving. At 17, I went, and was told my eyesight was practically perfect - but since they were free on the NHS, she would still prescribe the -.25 my left eye could use (seriously, one eye being .25 out is the minimum wrong that they're capable of detecting). If you're having trouble seeing, and need it corrected, try for a second opinion. If you've just been told by someone that you'll need them in the future, see if time sorts it out. There's certainly absolutely nothing to be gained by purposefully damaging your vision. If you're desperate to start wearing glasses, you could pay for some with flat glass in both eyes, but if people ask you why you're wearing them, that could be an interesting conversation. --Mnemeson 23:50, 9 September 2006 (UTC)

September 7

Value of chemical elements

I noticed that the value of germanium in 1997 and 2000 was provided in that article. That sparked the question: what is the best source for determining the current value of such commodities? Is there a reliable web source for finding this information. Much thanks in advance. I'd like to find a consistent source for updating this aspect of the chemical articles. LeyteWolfer 05:57, 7 September 2006 (UTC)

'Spot' markets/commodity markets deal with commonly traded elements. There is data available on rare elements, I saw it recently (osmium data I think, and from a US govt source (less certain abt this)), but I can't remember where. That doesn't help at all, does it? Rentwa 06:53, 7 September 2006 (UTC)

No, I'm afraid not, but thanks for trying. LeyteWolfer 22:22, 7 September 2006 (UTC)

The USGS Mineral Commodities Summaries, here generally include average prices for the years of the reports. Geologyguy 20:05, 8 September 2006 (UTC)

Geologyguy, you, my friend, are a god amongst men. Thanks a lot. LeyteWolfer 18:22, 9 September 2006 (UTC)

Weight versus elevation.

As you go farther from the center of the Earth, your weight decreases due to a weaker acceleration. How much does your weight alter from the Earth from an increase or decrease in elevation? Say I move from a place of lower elevation to a place of an increase in 500 feet of elevation. About how many pounds theoretically did I lose in weight? -User:NealIRC 7 September 2006 2:05 (UT)

Try staring at Newton's inverse-square force law, and think about the radius of the Earth. Melchoir 02:00, 7 September 2006 (UTC)

It's more complex than one would think, since you can't view the mass of the Earth as a point mass at the center until you are tens of thousands of miles into space. Instead, the mass of each atom, whether solid, liquid (water), or gas (air), must be considered, along with your distance from each atom. I've heard that the force of gravity actually increases slightly when you gain a little bit of altitude, due to the added mass of air below you pulling you down and the reduced mass of air above you pulling you up. StuRat 02:28, 7 September 2006 (UTC)

If we can approximate the physical earth as a nested collection of spherically symmetrical homogeneous shells, then the point mass simplification is fully equivalent for Newtonian physics as long as you stay on the outside. --Lambiam 02:53, 7 September 2006 (UTC)

Melchior and Lambian are right. It's easy to calculate. Clarityfiend 04:05, 7 September 2006 (UTC)

No, because the atmosphere does count. While it's mass is far less, it is far closer, if you are, say 1 km off the ground, so still has a rather significant effect on the net gravitational effect. Only after you are completely outside the atmosphere would such as approximation become accurate. The density of the Earth is also far from constant, which makes the point-mass model less accurate. See shell theorem for more detail. StuRat 04:20, 7 September 2006 (UTC)

Actually, as long as the density profile is spherically symmetric, the point-mass model is still good. As for the atmosphere... anyone want to crunch numbers on the two competing effects? Melchoir 04:25, 7 September 2006 (UTC)

The atmosphere has no significant effect, since the gravitational force falls off as r squared. There just isn't enough mass close enough to do much. Also, the non-symmetric density of the Earth doesn't really affect things either. The fact is there is a point where, if all the mass of the Earth were concentrated there, you would feel the same gravitational pull. For purposes of the original question, that's good enough. The non-homogeneity might move it a few miles one way or another (the oblate spheroid shape of the Earth too), but who cares? Compared to the distance between the point and the surface, it's negligible. Unless you're looking for ultra-accuracy, Newton's equation will give you a pretty good answer.

Here's a few rough numbers for the effect of the atmosphere (using ballpark figures, but they will give a very loose upper limit). At 120 km up, according to the wikipedia article, an astronaut notices the atmosphere upon reentry, so let's use that. The density of air at sea level is 1.2 kg/m cubed (sorry, don't know how to do superscripts). So a half sphere surrounding our intrepid questioner would mass about 10 to the 15th kg if the density didn't drop off as you go up; for simplicity, I'm going to use that figure. I don't want to go through and have to integrate that, so let's use an average distance of say 1 km. Crunch the numbers and you get about 0.07 Newtons. That's making the terrible assumption that the gravitational force is all in one direction, which it isn't. Even with all the simplifications grossly inflating the force, that's really, really miniscule.

Finally, you'd get a 1% decrease in weight when you are about 30 km further up (roughly - I only have the Windows calculator to work with). Clarityfiend 05:02, 7 September 2006 (UTC)

Again assuming spherical symmetry, the atmosphere does not contribute to the gravitational acceleration experienced by a body on the surface. In general, for a body at distance R from the centre, only the part within a sphere of radius R around the centre contributes to the net gravitational effect. --Lambiam 09:48, 7 September 2006 (UTC)

On the other hand, whether you are close to the equator or near the poles makes a more important difference in your weight because of the centrifugal force. A quick calculation yields that if you are at latitude φ, the g acceleration you actually feel is reduced by approximately 8.544*10 m s * cos φ. This means that if you travel from the poles to the equator, your weight will change by, say, 7 grams. If you travel only within the country it can barely be more than one or two grams. That's however still comparable to the difference you get from the altitude difference above. – b_jonas 08:43, 7 September 2006 (UTC)

The gravitational force is inversely related to the distance squared. So if the distance doubles, the gravitational force is reduced to 1/4. More in general, you should divide the two distances. Assuming Earth can be treated as a point mass at the centre of the actual Earth (so at a distance of about 6000 km), then if you go up 1 km, the distance increases by 6001/6000 = 1,00016666, so the gravitational force decreases to (6000/6001) = 0,999666 of what it was. Earth's gravity says "an increase in altitude from sea level to the top of Mount Everest (8,850 metres) causes a weight decrease of about 0.28%". Let's do the math again, this time with the more accurate radius of 6372,8 km. (6372,8/(6372,8+8,85)) = 0,997228346. That's a decrease of about 0,0028. Or 28%. So either we're both right or we're both wrong or this is some weird coincidence. :) So if you weigh 100 kg (which I hope not), your weight will decrease by 280 grams when standing on top of mount Everest. That's about the weight of a meal.

500 feet is about 150 m, so that would then be something like a few grammes of weight 'loss'. You do the math. DirkvdM 09:14, 7 September 2006 (UTC)

That's not a meal for a 100 kg person, more like an appetizer. :-) StuRat 09:18, 7 September 2006 (UTC)

Carbon dioxide

With the growing scare in some social circles of the changing temperature on earth, carbon dioxide is constantly brought up as a greenhouse gas that needs to be cut down on. My question is would it be possible to somehow suck (extract) carbon dioxide from the atmosphere and put it in a solid state? - Tutmosis 01:23, 7 September 2006 (UTC)

Try Carbon dioxide sink#Artificial sequestration and Carbon capture and storage. Melchoir 01:27, 7 September 2006 (UTC)

There's way too much in the air for us to ever remove a significant portion with machinery. However, natural removal of carbon dioxide could be increased by increasing the number of land and/or sea plants. For example, algae growth could be encouraged by adding iron to iron-poor sea water. StuRat 02:22, 7 September 2006 (UTC)

I think that's been tried (dumping iron in the sea that is). I think I read about it in Discover magazine; can't remember exactly, but I think it didn't work out too well. (P.S. I think therefore I'm really not certain.) Clarityfiend 04:11, 7 September 2006 (UTC)

You are uncertain, therefore you are. DirkvdM 10:39, 7 September 2006 (UTC)

Yes it has been tried, with mixed interpretations regarding the outcome. More information and links to some of the studies can be found in the articles on Iron fertilization and Iron fertilizing (it has been suggested to merge the two articles). ---Sluzzelin 09:38, 7 September 2006 (UTC)

• There's an easy natural way of removing carbondioxide from the air which has the nice side effect of producing oxygen. It's called trees and if less of those were cut down and more of them were planted, things might be looking up... =- Mgm| 07:23, 7 September 2006 (UTC)

See Carbon dioxide sink#Enhancing natural sequestration for that. Not just trees, but plants in general. But their presence alone doesn't do the trick. They need to grow to absorb carbon. So we need fast growing vegetation. Trees are a bad choice for that. Weeds would be better. Of course a useful weed (feel it coming?) would be best. Hemp is a good one. It grows extremely fast and has many uses. Burning it would undo the effect, so that's a bummer for the potheads. But it is also a good source for fibers. Actually, it used to be grown extensively throughout the world for that purpose (for the sailing industry for example), but got discredited because of its 'medicinal properties' (actually, DuPont pushed that to get rid of the competition for their plastic, but that's a differnt story). It also consumes a lot of Nitrogen, which is present in pig poo, of which we have an excess here in the Netherlands, so we would be an excellent choice for doing this (yeah, right, great excuse I hear you think, but its a different variety of the plant I'm talking about here). Another use is for oil, which can also be used as a fuel. That way it gets burned and the CO2 is released back into the atmosphere, anulling the effect, but if it is seen as an alternative to fossil fuels, no CO2 is added the atmospehere - the net result is zero. It's an oil so it should fit into the existing infrasturcture quite well. And the oil company that seems to be most into alternative fuels, Shell oil, is also Dutch, so I wonder if they're looking ito this. DirkvdM 10:39, 7 September 2006 (UTC)

Carbon was/is stored in a solid state in coal, and in a liquid state in oil. The problem is we're releasing that stored carbon. If we could just stop and wait a few million years, maybe more will be laid down... I wonder if, like coal, any solid form we found would be a good fuel, and thus potentially released by later generations? Skittle 10:57, 7 September 2006 (UTC)

I understand that diamonds will burn, under the proper circumstances, in case using $100 bills for toilet paper has lost all it's novelty. :-) StuRat 01:47, 9 September 2006 (UTC)

pray mantis

how do you identify the gender of a pray mantis insect

It's called a praying mantis. StuRat 01:33, 7 September 2006 (UTC)

Preying mantis might be better considering the following discussion. DirkvdM 10:51, 7 September 2006 (UTC)

Well, they are carnivores (insectivores, to be specific), so they do prey on other insects, but the name is due to their stance, which resembles the common praying stance for people. It's name is an interesting example of anthropomorphitization.StuRat 17:13, 7 September 2006 (UTC)

I believe if you know the species (which is very hard to do), then size plays a major role. I think females are much larger. --liquidGhoul 01:41, 7 September 2006 (UTC)

Size is the best way — (talk) (Desk|Help me improve)

Is it true that the female mantis sometimes eats the male after the dirty deed? Or is that a myth? That would be one rather final way of determining the male. Clarityfiend 04:08, 7 September 2006 (UTC)

The article's talk page has a bit of discussion on that. Given the commonness (is that a word?) of the story, the article really ought to address it one way or the other. Melchoir 04:18, 7 September 2006 (UTC)

As always, a great place to go for this kind of stuff is The Straight Dope. Do they have an answer for this one? Yes, they do. EWS23 (Leave me a message!) 05:08, 7 September 2006 (UTC)

Yuck! Thank god I'm not a praying mantis. Clarityfiend 05:53, 7 September 2006 (UTC)

Clarityfiend, you must have missed the article on precisely this topic in Tuesday's Science Times (a regular weekly feature of the New York Times). ---CH 07:52, 7 September 2006 (UTC)

I'm a typing man-tis, ready to figuratively bite off the heads of those who want to impregnate Misplaced Pages with their POV and lousy prose. Clarityfiend 16:36, 7 September 2006 (UTC)

Possibly I'm being pedantic, but size is only a partial answer, because it's only helpful when used as a comparative. If you had just one specimen of a particular type of praying mantis, (or, for that matter, several hundred all the same size) you wouldn't be able to tell if it was (they were all) male or female. Any other ideas? --Dweller 09:44, 7 September 2006 (UTC)

That's why I said you need to know the species, and obviously their sizes. The females are usually considerably large enough to differentiate. If you get a small praying mantis, it may just be a small species, not neccessarily a male. --liquidGhoul 09:49, 7 September 2006 (UTC)

Vivisection! — (talk) (Desk|Help me improve)

Water Ananlysis

Hi, I want to test drinking water with ref. to Hardness, Chloride content & free chlorine content pls. provide me the procedure for same however it should be volumetric analysis...

Thanks & Regards,

Anant BendigeriPatil. +919881271587.

Hmm, I can help you with the water hardness. Obtain samples, say 50ml, add 10ml ammonia and solochrome black indicator, and titrate with c. 0.01M EDTA. n(EDTA) will equal n(Ca) . BenC7 10:32, 7 September 2006 (UTC)

Cyclone/Tornado

I was wondering what the difference between a cyclone and a tornado is.Do cyclones have a funnel like tornadoes do?Andreamiller 10:43, 7 September 2006 (UTC)

This is an ancyclopedia. See cyclone and tornado. The main differences (I believe) are size and duration and the fact that cyclones start over sea. DirkvdM 10:54, 7 September 2006 (UTC)

Thanks,I did actually read both the articles.But my main question was whether cyclones had a funnel or not.Serenacw 10:58, 7 September 2006 (UTC)

No, in the usual sense of the word, a cyclone is a hurricane, which has an eye in the center, not a funnel. However, the word "cyclone" is misused to mean tornado in parts of the US. StuRat 12:02, 7 September 2006 (UTC)

To be fully correct (from cyclone):

Cyclones are responsible for a wide variety of different meteorological phenomena such as tropical cyclones and tornadoes.

So, a tornado is a form of / caused by a cyclone in the formal sense. All cyclones have a rotation, though not all will have "funnels" in the usual sense. And of course, Stu is absolutely correct about colloquial usage tending towards tropical cyclone. — Lomn | Talk 13:26, 7 September 2006 (UTC)

Molecule Diagrams

What are some good programs for drawing 2D molecules (especially organic ones)? What is generally used for Misplaced Pages? How about 3D molecules? Thanks --Russoc4 14:01, 7 September 2006 (UTC)

See the "Drawing molecules" section above. --Andreas Rejbrand 15:17, 7 September 2006 (UTC)

Oops...sorry. --Russoc4 16:19, 7 September 2006 (UTC)

donations to medical science

I am 80 years of age female (4 children)widow and have had several surgeries. at this time i have 6 incurable conditions in my brain. i think that would make my body a good prospect for worthwhile study. i asked my doctor how to do that and he said my drivers license. surely not! so i am asking help to find out how to donate my body to medical science at my graduation to heaven !

my email is (E-MAIL REMOVED) and my mail address is (ADDRESS REMOVED).

if you cannot help me, please suggest another place at whick i can inquuire for help. thank you

signed.................elaine harbour

Dear Elaine,

I think that your doctor was referring to the "donor" checkbox that many U.S. licenses have on them (in California, it is a little pink sticker; in Massachusetts, it is printed onto the license itself). Each state does it a little differently.

I've Googled around Oklahoma's donor options and haven't found one that works through the DMV though. The two best places to contact might be a company called LifeShareRegistry, which is specifically for organ donation but might know about other donor arrangements, and Oklahoma State University's Center for Health Sciences Body Donation Program. Both of these places could probably point you in the right direction in respects to Oklahoma's specific donor procedures. I commend you on your desire to aid medical science. Thank you. --Fastfission 14:37, 7 September 2006 (UTC)

Of course Elaine thinks she's going to get emailed or written to, so she's not actually likely to come back here (and would probably struggled to find her way back here if she wanted tó, if she's a Misplaced Pages noob). --Username132 (talk) 18:34, 7 September 2006 (UTC)

So who's going to be the good Samaritan and email her the link to her comment?  freshofftheufoΓΛĿЌ  02:32, 8 September 2006 (UTC)

• I'll do it if I can track down the email adress in the history. - Mgm| 07:40, 8 September 2006 (UTC)

This diff. Delete it if you don't need it anymore.  freshofftheufoΓΛĿЌ  12:54, 8 September 2006 (UTC)

Why glass transparent?

fixed by LeyteWolfer 17:08, 7 September 2006 (UTC)

See transparency and glass--Light current 17:12, 7 September 2006 (UTC)

Because if it weren't I wouldn't be able to read this. DirkvdM 18:59, 7 September 2006 (UTC)

And we all know the rules of the universe were written so that Dirk could do what he wants to do, when he wants to do it. ;o) EWS23 (Leave me a message!) 19:23, 7 September 2006 (UTC)

Haha! It's the anthropic principle. -- SCZenz 02:06, 8 September 2006 (UTC)

Indeed. We use glass because it's transparent. – b_jonas 21:11, 8 September 2006 (UTC)

Glass *Isn't* transparent. Use a Thermal IR camera to look around, and you'll find that glass is shiny and opaque, like a mirror. Now garbage bags, plastic shopping bags, etc., those this are totally transparent.

Sailors' Dead Winds

What are the things called where sailors would get stuck with out trade winds for days?

• Perhaps you are referring to the Doldrums? --Nebular110 17:54, 7 September 2006 (UTC)

• Doldrums. LeyteWolfer 17:54, 7 September 2006 (UTC)

No, that's a specific region where that phenomenon often occurs, but the question was for the name of the phenomenon. The answer is at the tip of my tongue, but can't break that barrier so to say. :) Then again, the question is specifically about the trade winds, so that's confusing. Anyway, that excludes the doldrums, because that is the area around the equator where there are no trade winds (if I understand it correctly). DirkvdM 19:11, 7 September 2006 (UTC)

I'd imagine the original poster was probably referring to the doldrums or the horse latitudes. If there's a word for the actual occurence of getting stuck there, as Dirk suggests, I haven't heard of it. EWS23 (Leave me a message!) 19:27, 7 September 2006 (UTC)

I'd say becalmed would be a fairly accurate description. GeeJo ⁄_(c) • 20:25, 7 September 2006 (UTC)

To be in the doldrums is to be becalmed surely?--Light current 02:37, 8 September 2006 (UTC)

Probably. But to be becalmed is not necessarily to be in the doldrums, particularly if you happen to be 1000 miles away at the time. JackofOz 04:04, 8 September 2006 (UTC)

Dead Calm

Handwashing

Can I hand wash clothes using regular (designed for washing machine) detergent, so long as I wear rubber gloves? --Username132 (talk) 18:26, 7 September 2006 (UTC)

I suppose you could, but liquid dish washing detergent works better for hand washing laundry. StuRat 18:48, 7 September 2006 (UTC)

Wouldn't that fade or otherwise damage the clothes? --Username132 (talk) 19:12, 7 September 2006 (UTC)

No, dishwashing detergent is much more gentle on clothes than laundry detergent, and some is even labeled "for use with delicate hand washables". The only concern might be that it would be less effective at removing serious stains, so I'd use a stain spray for that. StuRat 06:04, 8 September 2006 (UTC)

Yes you can, and personally I think laundry should be washed with laundry soap, and dishes should be washed with dish soap, and not vice-versa. :-) Anchoress 18:51, 7 September 2006 (UTC)

I have done that regularly when travelling. I supose it's not too good for the hands, so don't do it too often. Actually, in Cuba I got these areas of hardened skin that the doctor detected when I visited her for something else. It was easily soved with some ointment (can't remember what), but she told me to better not wash by hand. An overcautious doctor, I suppose. Funny StuRat mentions dishwashing detergent, because I use that for everything but my laundry (and my body). So I can now do away with the clotheswashing detergent as well? Less practical for travelling, though because it's a fluid and therefore too heavy. DirkvdM 19:16, 7 September 2006 (UTC)

You can use dishwashing detergent as emergency body soap and/or shampoo, too, but you need to dilute it with water first, or it's difficult to rinse off. I've used it myself when I ran out of the normal stuff, and it worked fine. StuRat 03:37, 10 September 2006 (UTC)

When traveling, I have used bath soap to wash clothes, and that works okay, too. It also doesn't really require gloves. Marco polo 19:43, 7 September 2006 (UTC)

Couldnt you do it by just having a bath with your clothes on?--Light current 01:41, 8 September 2006 (UTC)

Yes, but you're not going to enjoy the next thirty minutes in the dryer very much.--192.168.1.1 05:19, 8 September 2006 (UTC)

Actually, I met soneone who travelled with one set of clothing who did just that. In the tropics it can be wonderful to walk around in wet clothes. DirkvdM 07:07, 8 September 2006 (UTC)

Portal to define pictures of plants or animals

Hello, is here in the english Misplaced Pages a Portal to define pictures of unknown plants or animals, like in the german Misplaced Pages? Greetings --Ruestz 19:00, 7 September 2006 (UTC)

You could also upload to Wikimedia Commons (which is a better place to put photos because from there they can be accessed from any wiki project) and then place them at http://commons.wikimedia.org/Category:Unknown_species. try to put them in the most specific category you can find. Alternatively, ask at the most relevant talk page. By the way, the word is not 'define' but 'determine'. Wie auf Deutsch glaube ich, 'determinieren', nicht? DirkvdM 19:27, 7 September 2006 (UTC)

People usually just ask here, or on Misplaced Pages talk:WikiProject Tree of Life. There's no definitive place as far as i know. —Pengo 14:25, 9 September 2006 (UTC)

Thank You for the informations --Ruestz 22:32, 9 September 2006 (UTC)

Kuiper belt

The article states the majority of Kuiper belt objects were found after 1992, but it does not elaborate on why that is the case. Could someone please answer that, and place it in the article; as I feel the context would be helpful. - RoyBoy 19:49, 7 September 2006 (UTC)

I'd speculate its because either:

• The technology required to see them was not yet available

• No-one looked in the right place at the right time with the right telescope

The reasons why someone didn't find/do something before anyone else is usually speculative and thus may be why it isn't in the article. Still, if anyone can source it... Rockpocket 01:31, 8 September 2006 (UTC)

I'd guess the Hubble Telescope, launched in 1990 and upgraded/corrected with COSTAR in 1993, was the source of this new data, as it was a major improvement over Earth-based optical telescopes. StuRat 05:53, 8 September 2006 (UTC)

I suspect that the Hubble isn't used explicitly for KBO surveys—it's field of view is too narrow and telescope time is too precious to go trolling for asteroids. It's possible that some might be discovered serendipitously while examining other objects. The HST can be used for examining these objects in (more) detail once they have been discovered, however. TenOfAllTrades(talk) 12:31, 8 September 2006 (UTC)

David C. Jewitt and Jane Luu discovered the first Kuiper Belt object in 1992 using a telescope in the Mauna Kea Observatory. Looks like people simply started looking for more. One of the larger KBOs, 90482 Orcus, can be seen in photographs from 1951 but nobody noticed it for fifty years (you can't just look at a photo and go "ha, a new planet!" You need to painstakingly compare many photographs from different times and detect tiny movements of very faint blobs to tell stars and moving rocks apart. You need to know what you are looking for.)

In a Scientific American May 1996 article Jewitt and Luu say that since the initial find a bunch of research groups have joined the effort and found a steady stream of KBOs. Weregerbil 08:46, 8 September 2006 (UTC)

When you mention Jewitt and Luu and 1992, you probably mean (15760) 1992 QB1. But that wasn't the first KBO found. As that article points out, Pluto was first, in 1930, and Charon second in 1978. QB1 was the third. -- Plutortalkcontribs 12:08, 8 September 2006 (UTC)

I think there is a distinction between "KBO found and known to be a KBO" and "discovering something which we now consider a KBO but was at the time considered a planet and a moon". --Fastfission 14:50, 8 September 2006 (UTC)

Indeed. In the last fifteen or twenty years there have been several major advances which have made searching for KBOs much easier. The computer hardware and software for automated image analysis (trying to find the one bright speck that isn't a star or known object) has gotten both better and cheaper. CCDs have become much cheaper and much improved in quality, allowing sky surveying without the messy intermediate steps involving photographic plates. Finally, several medium-large aperture telescopes (0.9 meters and up) have been configured for automated sky surveys in the last fifteen years—nobody's been looking very hard for KBOs until recently. TenOfAllTrades(talk) 12:31, 8 September 2006 (UTC)

One lung breathing

In the show Malcolm in the Middle, the character Stevie has (I think) only one lung and breathes a deep breath after every word. Is this medically correct? Reywas92 19:50, 7 September 2006 (UTC)

Stevie is chronically short of breath because he has severe asthma. I can't comment on the medical plausibility of his case, other than to say that if it were a fair clinical picture, Stevie would represent the more severe end of the chronic asthma spectrum.... TenOfAllTrades(talk) 21:50, 7 September 2006 (UTC)

• I doubt that is possible, Reywas92. One long is not enough to provide the body with the oxygen it needs and he would need to be on constant additional oxygen which he's not. - Mgm| 07:36, 8 September 2006 (UTC)

Actually, one lung is enough to provide a person with the oxygen they need. Pneumonectomy (removal of one entire lung) is a surgical procedure for treating advanced lung cancer. Patients with one lung are limited to a modest level of physical activity, but otherwise can lead mostly normal lives. They don't need constant additional oxygen and are not confined to a wheel chair, like Stevie. --Ed (Edgar181) 13:07, 8 September 2006 (UTC)

Yeah, it's possible. Before modern antibiotics, tuberculosis was often treated by artificially collapsing one lung for a few days to create an environment unhospitible to the bacteria. With the plethora of new strains of resistant Tb, you may hear about this procedure in the future too...Tuckerekcut 04:25, 10 September 2006 (UTC)

The Guinness World Record: Bruce Geiling (born June 7, 1923) lost his right lung to cancer on April 10, 1969, and is still leading a healthy life on August 14, 2004. Neal 14:55, 10 September 2006 (UTC).

Can guinea pigs eat lettuce?

I read that iceberg lettuce is bad for guinea pigs. Is this true? Reywas92 19:52, 7 September 2006 (UTC)

Iceberg lettuce is pretty low in nutritional value—it's mostly "crunchy water". Neither guinea pigs nor humans get much out of the stuff; we only eat it because it's a convenient vehicle for salad dressings.

In larger quantities, the high water content and (probably) nitrates in the lettuce can cause various sorts of digestive upsets. Small amounts probably won't do any harm, but they're not beneficial either.

Consider something dark green and leafy, instead: kale, dandelion leaves, spinach, clover, or parsley. TenOfAllTrades(talk) 22:00, 7 September 2006 (UTC)

• We used to give our guinea pig nl:witlof. Unfortunately, there doesn't seem to be an English article on the stuf... - Mgm| 07:35, 8 September 2006 (UTC)
  • That's Belgian endive. feydey 13:42, 8 September 2006 (UTC)
    • Witloof was a redirect to endive. I've created witlof as one, too. -- Plutortalkcontribs 12:01, 11 September 2006 (UTC)

Yes. I don't know the mechanism behind it, but iceberg lettuce causes diarrhea and/or non-normal feces in guinea pigs and other animals. First hand info, I'm afraid - stick with romaine leffuce.  :-P As an aside, my daughter recently caught a caterpillar and when it refused some of the leafy stuff from outside, we stuck some iceberg lettuce in the terrarium for it - it also had loose feces. Not sure why *I* keep eating it... Matt Deres 19:28, 10 September 2006 (UTC)

How can I, as a white man get natty dreadlocks without having to pay for them?

I know that black ppl's hair naturally forms into dreadlocks if they don't brush or wash it for a long time. Is this true for white people too? How long would it take for the dreads to form if I decided never to touch my hair with anything again (it's already past shoulder length)? Some people might say it's gross to never wash your hair but I heard that the hair starts cleaning itself naturally after a while anyway.

I don't want salon dreads. I can't afford them.

It's not whether or not you wash your hair, it's whether or not you comb it. Here's an article called How To Make Dreadlocks and How To Make Dreadlocks - tips. Maybe that will help. Anchoress 21:34, 7 September 2006 (UTC)

Just completely ignore your hair.. I mean wash it and stuff, but don't hair care it, and it will matt. When it's matted just pull the matt into strands as thick as you want your dreads. Philc _TC 21:37, 7 September 2006 (UTC)

So can Chinese people get dreadlocks than? It doens't sound right. — (talk) (Desk|Help me improve)

Sure, if they have hair that isn't straight. "It doesn't sound right" because you're not used to it, but I'm sure there are at least a few. ColourBurst 18:41, 8 September 2006 (UTC)

I once met a guy who after hiking through the Tasmanian bush for a few days noticed he couldn't get a comb through his hair. So it was either cut the hair or develop dreadlocks. he chose the latter. I believe something similar happened to Keith Richard.

Yup, it's a matter of not combing your hair. I just wonder if you can 'sculpture' the dreadlocks. What if a dreadlock develops you don't like? Some look messy, others look neat, is there a trick to that? And bums nowadays often have dreadlocks, which makes sense, so it doesn't make sense that that would be a recent phenomemon. So did they have them in previous centuries too? DirkvdM 07:19, 8 September 2006 (UTC)

I haven't combed/brushed my hair in years, and I don't have light, straight hair. I also don't generally "treat" it, just shampoo and the monthly conditioner or so. I had a roommate up until a couple of months ago with huge dreads, and although he washed them, I don't think he did very often. Something like, "When I start to smell it too, that's when I wash".  freshofftheufoΓΛĿЌ  07:28, 8 September 2006 (UTC)

One of us has a nephew who just put toothpaste in his hair. dreadful it was, but it was quite dreadlockish. -- DLL 16:26, 9 September 2006 (UTC)

What if you don't brush your teeth for a long time? Will you get dreadful teeth then? I suppose so. DirkvdM 08:02, 10 September 2006 (UTC)

Yes. --Proficient 04:52, 11 September 2006 (UTC)

Sodium vs sodium chloride in foods

When a food label in the US (FDA regulated) claims sodium content, do they really mean sodium chloride as in traditional edible salt or is this the mass of any digestible form of sodium in the food? As a follow-up, does the human body use sodium or sodium chloride specifically to regulate hydration? When reading over the articles, it's hard to tell if terms are used loosely. p.s. this isn't homework, I swear! --Jmeden2000 21:31, 7 September 2006 (UTC)

As to the first question, my guess is they really mean sodium, but it's just a guess. The second question I can answer a bit more definitively: When sodium chloride is dissolved in water (as it will be in your body) it dissociates almost completely. So what counts is sodium ion, Na; your body has no way of knowing if it was part of sodium chloride or some other sodium salt. --Trovatore 21:39, 7 September 2006 (UTC)

THe main source of sodium in the diet must be sodium chloride. I cant think of any other sodium salts that we eat in any quantity.--Light current 22:24, 7 September 2006 (UTC)

edit conflict: yeah they mean total sodium content, from salt, baking soda preservatives etc. because it's all sodium in the end. the sodium ion is important, for example in the Na+/K+-ATPase. not to say chloride isn't important too. and i think they measure sodium due to its role in heart disease, but i'm unsure. Xcomradex 22:29, 7 September 2006 (UTC)

and just for light current: sodium bicarbonate, sodium benzoate, monosodium glutamate... Xcomradex 22:29, 7 September 2006 (UTC)

Apart from monosodium glute a mate (used as flavor enhancer). How much sodium bicarb and sodium bezoate do we eat?--Light current 22:33, 7 September 2006 (UTC)

• sodium benzoate: FDA maximum of 0.1% w/w
• sodium bicarbonate: from cookbooks seems about one teaspoon (5g)/ cake

bear in mind we don't usually put a lot of salt on meals in w/w terms. but is still probably the major source, due to its ubiquity. Xcomradex 23:08, 7 September 2006 (UTC)

1gm NaCl contains 0.4 gm sodium--Light current 23:31, 7 September 2006 (UTC)

it does, but remember we don't put 1g salt on a 100g steak. Xcomradex 01:06, 8 September 2006 (UTC)

I dont put any on. But there again I dont eat steak.--Light current 01:08, 8 September 2006 (UTC)

By the way, the unit sign of "gram" is g. gm is "mostly obsolete" when referring to grams, unless you were actually talking about giga-meters.  freshofftheufoΓΛĿЌ  02:24, 8 September 2006 (UTC)

Gm is used for Gigameters. StuRat 00:42, 10 September 2006 (UTC)

THanks for that 8-)--Light current 02:25, 8 September 2006 (UTC)

Sodium is what's used for hydration. Chloride is the most important anion in the body because it is the most common. However, the sodium is what's regulated and the chloride usually just follows! InvictaHOG 09:56, 8 September 2006 (UTC)

Follow up

First of all thank you to all who answered, this has been most informative. I would like to add another sub question: how do you suppose all animals developed a heavy reliance on sodium if it is so rare to occur in plants? (as per the sodium article). Surely primitive mammals were not digging salt mines or evaporating sea water... So where in the food chain does it all come from? --Jmeden2000 17:22, 8 September 2006 (UTC)

Salt lick. --Serie 19:34, 8 September 2006 (UTC)

While life evolved in the ocean, where there is plenty of salt, I agree that it does seem odd that, once animals moved onto land where salt is scarce, they weren't able to evolve to better match this low salt diet. I would have to conclude that it's just extremely difficult to break this dependency. StuRat 21:42, 8 September 2006 (UTC)

thats right sturat. the sodium ions are used to produce a concentration gradient across the cell membrane, which then allows essential compopunds such as amino acids to be brought into the cell and concentrated by active transport, with the change in sodium concentration making the whole process positive in entropy terms. the system is of such a fundamental importance, i'd doubt whether the necessary genetic variation could exist for evolution to occur. Xcomradex 22:39, 8 September 2006 (UTC)

I thought it might be useful to add sodium sturate in a regular diet. -- DLL 15:21, 9 September 2006 (UTC)

Mutism

I recently watched a TV drama in which one of the main characters got in some kind of accident and lost her hearing. She chose to start using sign language exclusively because she couldn't hear the sound of her voice and was ashamed about the way she assumed it would sound. That said she did talk occasionally during the show, with a very nasal voice, the kind one might usually associate with a person unable to hear from birth. I'm not sure how realistic the drama is supposed to be, but I'd be a little shocked if there was such a big misconception as that. Do (could) people who become deaf (suddenly?) lose the ability to speak in a fashion that they were able to before they became deaf? I couldn't find any mention of it at speech disorder or deaf culture.  freshofftheufoΓΛĿЌ  22:21, 7 September 2006 (UTC)

I've heard radio-interviews with people who lost their hearing and their speech was completely 'normal' and melodious to my ears. Singing, where the frequencies and modulations have to be more accurate, is a different thing; I distinctly remember listening to a woman who had lost her hearing years ago sing Amazing Grace, and it was hard to recognize the melody. Percussionist Evelyn Glennie almost entirely lost her hearing at the age of twelve and speaks like a hearing Scottish person too, as can be heard in the documentary film Touch The Sound. ---Sluzzelin 05:59, 8 September 2006 (UTC)

The problem with that, I guess, is that deafness usually isn't absolute, and at least some of the people you mentioned might have some awareness of the sounds coming from inside their bodies (Evelyn Glennie's article notes that she has "very limited hearing"). Failing that, it seems that at the very least it may not be expected for someone to lose the ability to speak properly along with their hearing, though I wonder if there are exceptions. I actually quite liked the drama so I kind of want it to not be a complete farce!  freshofftheufoΓΛĿЌ  07:11, 8 September 2006 (UTC)

This is also why singers (and instrumentalists for that matter) need feedback through a monitor on stage. If they can't hear their own voice they can't sing in tune. I wonder if classical singers before a full orchestra (which can be a lot louder than a rock band) use this too. I don't recall ever seeing it. DirkvdM 07:25, 8 September 2006 (UTC)

No they dont. THey can belt it out at much higher levels than pop singers so they can hear themslves ok. Also the orch tends to come down under the singer a bit.--Light current 07:38, 8 September 2006 (UTC)

(Edit conflict) You're right. And a further difference to the TV drama, is that most people lose their hearing gradually, allowing them to closely monitor and correct changes in their speech. Googling "traumatic mutism" or "post-traumatic mutism" leads you to some neurological websites discussing this phenomenon. In the cases I found, mutism was explained psychologically and not linked to the loss of sense of hearing.---Sluzzelin 07:34, 8 September 2006 (UTC)

Ok ok, but I'm losing the original question. I don't think there was any post-traumatic mutism or anything like that, the show explained her "nasal speech" to the extent that it was only a concequence of her loss of hearing, which in turn was caused by some sort of car accident I think. Anyway, I think it's pretty clear that this drama was a little bit scrubbier than I initially thought. Loss of tone recognition doesn't really explain either why she would suddenly sound nasal. Oh well, thanks guys!  freshofftheufoΓΛĿЌ  12:03, 8 September 2006 (UTC)

September 8

How large are the Mars rovers?

I'm curious to know the dimensions of the Opportunity and Spirit Mars rovers. I can't seem to find these specs on the Internet. Thanks!

Cruise vehicle dimensions: 2.65 meters (8.7 feet) diameter, 1.6 meters (5.2 feet) tall Rover dimensions: 1.5 meter (4.9 feet) high by 2.3 meters (7.5 feet) wide by 1.6 meter (5.2 feet) long

Weight: 1,062 kilograms (2,341 pounds) total at launch, consisting of 174-kilogram (384- pound) rover, 365-kilogram (805-pound) lander, 198-kilogram (436-pound) backshell and parachute, 90-kilogram (198-pound) heat shield and 183-kilogram (403-pound) cruise stage, plus 52 kilograms (115 pounds) of propellant

From mars tv. Also, check out Mars Exploration Rover ---Sluzzelin 06:51, 8 September 2006 (UTC)

Useful fictions inside of science

What are some useful fictions that have been created for calculational purposes similar to a center of mass/gravity? A center of gravity isn't an actual feature of matter, just something we impose upon matter in order to help make our calculations easier for a given system. Thanks--droptone 12:32, 8 September 2006 (UTC)

See WP's articles on mathematical models in physics, and on theory. ---Sluzzelin 12:48, 8 September 2006 (UTC)

That reminds me of a joke my boss once told me about calculating the surface area of a chicken. First you assume that it's a perfect sphere... – ClockworkSoul 12:53, 8 September 2006 (UTC)

I remember this book: Consider a spherical Cow was quite popular a while back.---Sluzzelin 13:05, 8 September 2006 (UTC)

Depends how broad you want to make you definition of fiction. You could say that energy and entropy are useful fictions, since you can't measure them directly - you have to infer them from other properties of an object or system. And temperature, pressure, density and viscosity are all average measures that only make sense for a large population of atoms or molecules, so you could argue that they are also fictions. Velocity depends on your frame of reference, so maybe that is a fiction too. In fact, the only properties that are truly "features" of elementary particles seem to be spin, charge and mass. Gandalf61 14:45, 8 September 2006 (UTC)

• Newtonian physics is technically wrong, in that it doesn't account for relativity, but still widely used for most calculations.

• The Dalton model of the atom, while useful for basic chemistry, is not as useful in particle physics.

• Planetary and lunar orbits are approximated as ellipses, while the true orbits must account for various perturbations.

• The "no air resistance" model of ballistics.

StuRat 19:35, 8 September 2006 (UTC)

Body Mass Index assumes every human has an identical body shape, but is effectively used to determine obesity. While it could be improved by using body shapes or even getting an extremely accurate BMI by weighing people in water, the difference between BMI and the highly accurate indexes is statistically insignificant for nearly all people. --Kainaw 20:12, 8 September 2006 (UTC)

By fictions do you mean specifically fictitious entities that we postulate in science, or just any (probably false) assumption made in a scientific theory? Lumping the two together, here are a few:

1. The perfect rationality assumption used in the Homo economicus model of human behavior is often defended as a useful fiction.
2. Infinite populations are often used in evolutionary game theory and population genetics models in biology, these are certainly false assumptions. (There's actually a list at replicator dynamics.)
3. The use of frictionless planes in physics. (Or really just about any calculation done in an intro physics class and most engineering classes.)
4. Point particles used in Newtonian mechanics, special relativity, and general relativity.
5. Fluid dynamics assumes that fluids are continuous, they're not.

I attended a talk recently about use of fictions in computer simulation modeling, the video is archived here (its the second talk). As I recall he makes a distinction between "fictions" and "modeling assumptions." But he has a bunch of interesting examples. --best, kevin 22:00, 8 September 2006 (UTC)

Chicken? Cow? Feynmann always called it a horse. — (talk) (Desk|Help me improve)

Isn't any unit an abstraction and therefore fiction? An object doensn't have any metres in it, length is a quality we assign to it. In more practical terms, what is your height? One part of this is the issue of precision. Any measurement is an approximation and therefore not exact. So is it real? But there is also the definition of someone's length. Do you include the hair on your head (if any)? If so, is it combed? What about the length of a punk with a Mohawk hairstyle? Converrsely, the centre of gravity is just as real as the geometric centre and therefore the radius of a planet (another use of the quantity 'length'). DirkvdM 12:41, 9 September 2006 (UTC)

I'm not sure if this is what you're looking for, but consider the planet Earth. We've assigned it all sorts of "scientific fictions", such as its axis (there's no actual rod connecting the North and South Poles!) and the "imaginary line" we call the equator. Similarly, the "imaginary lines" we call the tropics of Cancer and Capricorn, the Arctic and Antarctic "circles", and pretty much every other "line" of longitude and latitude. I could go on, but as I said, I'm not sure if this is exactly what you're looking for. Loomis 22:23, 12 September 2006 (UTC)

Help to identify spider

Hello, can someone please tell me what spider this is? Or at least if it is poisonous? Sorry for the bad pic but I only had my cellphone camera available at the time. I live in Gauteng, South Africa. I am afraid for my children's safety. The spider is about as big as a toddler's hand. One enters our house every week or so. If I wave an object like a broom near it, it raises its front legs (?) towards the object. Is this a defensive or aggressive pose? Sandman30s 14:13, 8 September 2006 (UTC)

That picture really isn't very much to go on. I believe, in general, that when a spider raises its front legs it is generally an aggressive, "Look at my teeth" pose, but I only know about Australian spiders in that respect. This page contains pictures of some of the more "medically important" spiders of South Africa that you can compare it with. Apparently South Africa also has trapdoor spiders and baboon spiders, neither of which would be very fun to get bitten by. Again, I'm not a spider expert in any respect, though. If I had to guess by the picture alone, the long-legs, big-head would make me worry that it was a violin spider, which have poisonous (but not always deadly) bites. I would definitely try to kill it in any case—a shovel would be my method of dispatching it, personally. --Fastfission 14:43, 8 September 2006 (UTC)

Thanks very much for the detailed answer. My best guess from all those pictures is the lesser baboon spider (HARPACTIRELLA), it doesn't look like the violin spider due to a different colour, unless the violin is also dark brown with dark red and black legs. I will try to get a better pic the next time, sorry. Also if the spider is not poisonous, I would not like to affect the ecosystem around the house, as the spiders would reduce my overpopulation of crickets :)

I'd much rather have the crickets. :-) StuRat 19:21, 8 September 2006 (UTC)

Not to be too much of a pedant, but all spiders are venomous. I have no idea whether this particular spider is dangerous, however. --Ginkgo100 20:18, 8 September 2006 (UTC)

Are you sure? I remember that that was some sort of urban myth. I'd check Snopes if I had the time. - Mgm| 20:45, 8 September 2006 (UTC)

Correction to the above from spider: there are a few species not able to inject venom. --Ginkgo100 20:23, 8 September 2006 (UTC)

Really, there are only a few, as in 14 or less if I recall correctly, and they all live in remote regions of the jungle. I created two articles, and some redirects a while ago, when a new species was discovered that did not have any venom. Instead, it traps prey in it's web, then bundles it up, tigtens the cords until the prey is broken to pieces. The spider proceeds on to regurgitate digestive juices, pour them onto the prey, wait, then feast. — (talk) (Desk|Help me improve)

Looks like a "jagspinnekop" (Palystes sp. - African hunting spider), especially as you mention the striped legs, and the very typical raising of the front legs when threatened. The raised legs are impressive, but only a show - it does not attack that way. It hunts at night, and has no web as such, just a nest which takes 2-3 days to build. Though one cannot judge size, it looks like a youngster you have there (inter alia it still has 8 legs!). Also called a "reënspinnekop", (rain spider) from it's alleged habit of appearing inside when rain threatens. This spiders's bite hurts like a bee-sting, but won't kill - unless you get a heart attack from fright. It normally runs away - very fast once it starts running - to a dark corner somewhere. If you have trees outside (or dense bushes or ivy on a wall) you may find its large fist-sized nest of leaves, twigs and silk hanging inside the denser growth - be cautious, the female guards the nest. I leave them be, they don't build nests inside your house, and I've watched them catch other goggas inside at night. They definitely eat crickets, but there is no way they will prevent the periodic "cricket epidemics". If you wish to catch it, it is legal to keep it, and you can handle it if you don't mind an occasional bee-sting-bad bite. Contact a museum to find the correct diet, etc. The site also gives advice on how to catch it and return it outside. I normally use a plastic shopping bag which I place over it and then coax it into the bag, trying not to hurt the legs, then leave the bag open in a tree. The "bobbejaanspinnekop" (Harpactira/ella you mentioned - Therasophidae - Baboonspider) is bulkier, legs relatively shorter and oriented differently, more hairy, does not show the clear markings you mention, does not typically show that same threatening stance, and is a protected species, because of a demand as "pets" in the first world countries. Searching the web for "rain spider" or "hunting spider" should give the best results if you want to know more. --Seejyb 20:55, 8 September 2006 (UTC)

Still hard to identify but looks very much like the second pic on this page you talked about - the huntsman. These things become absolute monsters (size of adult hand) and don't seem infected by normal insecticide - will given it's not an insect :) Good to know it's not worse than a bee sting. Will definitely get a better pic next time to get a proper ID. And for the record - I freakin HATE CRICKETS! Their incessant ventriloquist chirping interferes with some frequency in my brain and I cannot sleep and cannot find the little buggers, in the day or night! GRRR. And to make it worse we get 'Parktown Prawns' (King Crickets) where I live - harmless but they have to be the ugliest darn things alive (good at hiding too). Ugh. Sandman30s 22:26, 8 September 2006 (UTC)

Cats are good at catching crickets. User:Zoe|(talk) 23:19, 8 September 2006 (UTC)

Sounds like a much better choice to me. StuRat 01:22, 9 September 2006 (UTC)

Yeah, I would say it's a huntsman. We have plenty of them in Australia. They tend not to be aggressive, as you can see from the article page. BenC7 09:06, 9 September 2006 (UTC)

Having lived in South Africa I think "seejyb" above is right on the money with the answer - though I have found that catching the spider is a simple task using a large glass and a sheet of paper - approach slowly and place the glass over the spider trapping it then slip the sheet of paper under the glass wait a while and the spider will crawl to the bottom of the glass hold the paper in place and take the spider in the glass outside and shake it out onto a bush or tree. The spider lives! and you are rid of it!Cycloneweaver 16:50, 12 September 2006 (UTC)

diabetes in cats

Can someone please advise what choices for cats are available? My vet is at a loss as to bringing down the insulin level. i've tried humulin u, humulin m, and nothing works. i'm getting pretty desperate.

Try feline diabetes and the wiki on pet diabetes for further links and references. Please understand that we can't give medical advice at the reference desk. Good luck and all the best to your feline friend. ---Sluzzelin 14:55, 8 September 2006 (UTC)

I have been using PZI with my cat with some success, my vet says she prefers it to humulin. In addition, putting them on a low carbohydrate diet is considered important and has resulted in a reversal of diabetes for some cats. My cat is on Hill's Prescription M/D. Of course, this is only one case, and I'm not a vet. --best, kevin 21:39, 8 September 2006 (UTC)

ribose sugar

Is a ribose sugar a reducing sugar

Look at the structure of ribose and see if it contains the substructures or other features that are consistent with those of a reducing sugar. DMacks 15:10, 8 September 2006 (UTC)

Paraffin lanterns & alcohol

Would it be possible to safely run a paraffin lantern on alcohol if you haven't got any paraffin handy? If not what could you run it on that doesn't need to be obtained from hydrocarbons. AllanHainey 15:35, 8 September 2006 (UTC)

Paraffin is a solid hydrocarbon while ethanol is a liquid alcohol. Because it's not really the solid wax of paraffin that burns, but rather the resulting liquid/gas, if your lamp can accomodate a liquid fuel, it may be able to run properly.--Russoc4 17:47, 8 September 2006 (UTC)

In the UK, paraffin is a liquid fuel, and paraffin wax is a solid - the constituent of candles. --G N Frykman 17:54, 8 September 2006 (UTC)

Forgot about that...well, ethanol may or may not work properly. I found a very indepth page describing and comparing many fuels that can be used in camping stoves. The same applies here, only the fuel has to travel through a wick. The only problem I can forsee with ethanol is that it boils relatively easily. It's also less efficient when comparing BTUs/lb. isopropyl rubbing alcohol is not recommended. --Russoc4 19:04, 8 September 2006 (UTC)

I'd tend to recommend strongly against the use of ethanol in a lantern. Ethanol burns with a hotter, bluer flame that doesn't generate much light and will be harder on your lamp hardware. In addition, it has a higher vapour pressure (meaning that heating it during lamp operation may result in various sorts of failure of your lamp, some quite dramatic) and lower flashpoint. TenOfAllTrades(talk) 21:15, 8 September 2006 (UTC)

I presume you are talking about a non-pressurised, wick-burning system. Alcohol, petrol, lighter fluid or any similar fuel will not be safe in a lantern designed for paraffin - you will create a fireball, if not an explosion. The machine is not designed to handle such highly volatile substances. In practice, a light vegetable oil does work, but it stinks. Turpentine should be a safe option, and also stinks. --Seejyb 22:01, 8 September 2006 (UTC)

Burn!!

It's my understanding that when you burn organics like wood, or sucrose, the impurities of water and smoke components are burned off leaving residual carbon behind. If this is true, why does this residue not continue to burn? Doesn't carbon oxidize to form CO2? --Russoc4 17:42, 8 September 2006 (UTC)

See charcoal--Light current 17:44, 8 September 2006 (UTC)

Many people confuse heating and burning. See destructive distillation. --G N Frykman 18:00, 8 September 2006 (UTC)

Soot – which is mostly carbon – is the result of incomplete combustion of organic matter. As long as the fire remains hot and well-supplied with oxygen, the carbon will burn off to form carbon dioxide. (Under conditions of inadequate heat or oxygen, you may instead end up with carbon monoxide.) TenOfAllTrades(talk) 18:09, 8 September 2006 (UTC)

So charcoal/coke is made by "heating" wood/coal, but not actually burning it completely in enough oxygen. I get that part. You didn't answer my question. What I don't get is that when wood burns completely, it creates ash, which glows for some time, but then dies out. Why does it not burn if it's mostly carbon? --Russoc4 18:51, 8 September 2006 (UTC)

IT'S NOT CARBON. I don't know about your ashes, but the stuff in my fireplace looks like white fluffy powder, plus a few lumps of charred unburned wood. A better question is: why do very tiny pieces of charcoal stop burning? Or this: what is "wood ash's" composition? Google searches say: calcium carbonate, potassium carbonate, aluminum oxide, magnesium oxide, and lots of other stuff. In other words, the ashes are the traces of minerals used by the tree. See: --Wjbeaty 23:41, 8 September 2006 (UTC)

Burning an organic material oxidizes it, leaving oxides of its component elements, the most common elements in organics are carbon hydrgoen and oxygen. I there is insufficient oxygen, you will be left with unoxidized elements. So hydrogen and carbon, you are unlikely to notice any hydrogen, and carbon is in the form of soot. Carbon needs the heat from the fire to form new bonds with oxygen, so will not spontaneously oxidize once oxygen is sufficient, so it will be left. Philc _TC 21:04, 8 September 2006 (UTC)

Oh... well, that does clear some things up. So essentially, a burnt up, blackened matchstick has no carbon, just other random impurities. --Russoc4 13:56, 9 September 2006 (UTC)

Er, no. A blackened matchstick will be black (primarily) because of the remaining unburnt carbon. (White residue is mostly mineral impurities.) Overall, the process of combustion releases energy; we see this as heat and light. However, the reaction – in this case, the combustion of carbon to form carbon dioxide – requires a small amount of energy to get started. Normally combustion is self-sustaining once started; a small amount of heat from the reaction is fed back in to the system to drive the oxidation of more fuel. This feedback loop breaks down, however, if too much heat is drawn away from the fuel. That's why you can blow out a match—your breath cools down the fuel (paper or wood) in the matchstick, ending further combustion.

This is also why charcoal is so difficult to light. You have add (and ignite) lighter fluid to charcoal to supply adequate intial heat to start the charcoal burning. Once ignited, however, charcoal will burn very hot. TenOfAllTrades(talk) 14:16, 9 September 2006 (UTC)

Ahh... ic now. Thanks! --Russoc4 16:53, 9 September 2006 (UTC)

Aldol Compound

Can anyone help me out on this one? I'm trying to figure out the name of this compound that results from an aldol reaction. It is a yellow solid with a molecular formula of C₁₈H₁₆O₃, and its experimental melting point is 167°C to 172°C. ChemFinder is no help either, unless I'm not looking in the right spot. --Russoc4 20:05, 8 September 2006 (UTC)

File:Aldol.PNG

• Try if you can get your hands on a book like the Handbook of Chemistry and Physics, BINAS or if you happen to be able to read Dutch the "Chemiekaarten". I would also recommend you draw up the different compounds that could result with that molecular formula and make a guess at which it is by determining whether long chains have a lower/higher melting point and how saturation affects it. - Mgm| 20:51, 8 September 2006 (UTC)
• If you do the guessing well it will reduce the number of compounds you need to look up. - Mgm| 20:53, 8 September 2006 (UTC)

I considered the Handbook. If I have to, I'll use it. Thanks though. --Russoc4 21:00, 8 September 2006 (UTC)

chemfinder won't be any help. break the compound down into its components, you've got the indanone, an (E)-configured exo alkene, and a dimethoxy substituted benzene ring. start combining the pieces into names, such as (E) 2-(3',4'-dimethoxystyrl)indanone. not iupac, but it'll fly. alternatively if you want to go iupac, start breaking down the functional groups even further. In the real world, software like chemdraw has automated the naming of such compounds, and you'll often see things referred back to structures (eg indanone 1) in order to make life easier. sing out if i've lost at some point, it's hard to gauge what level you're on. Xcomradex 22:56, 8 September 2006 (UTC)

I purposely made it hard to tell :P I'm only in my 1st of 3 sememsters of organic chem. We did this in our second lab, and though I'm not sure if we really need to identify the name, it can't hurt. We did this to practice recrystallization. I'm a chemistry major, as you might tell from my user page, which also lists my classes :D. No biggie if I can't get a good name though, but thanks for your help! --Russoc4 02:42, 9 September 2006 (UTC)

It can't have both "indan" and "styryl" in the name, since each of those substructures would include the α-carbon of the enone. If you like indanone as the parent structure, then the substituent is a benzylidine derivative. DMacks 06:03, 11 September 2006 (UTC)

i'd say they don't want you to name it in iupac terms, i'm up to six years (and counting) of org chem, and it still made me think. you'll pick up soon enough that iupac terms are just unwieldy for anything remotely complex. eg 2-oxy-6-(hydroxymethyl)tetrahydropyran-3,4,5-triol is unrecognisable, and it only gets worse when include stereochemical descriptors. but tell any chemist 'sucrose' and they'll know what you're on about straight away. good on you for going the extra mile though, that'll get you good marks. Xcomradex 04:02, 9 September 2006 (UTC)

American passenger rail profitability

Why is it that, despite the commercial viability of passenger railways in Europe and Japan, American passenger rail has never turned a net profit since 1930, four decades before the founding of Amtrak? C. M. Harris 20:09, 8 September 2006 (UTC)

Gasoline is far cheaper in the U.S. than in every European country I've been to (Norway, Sweden, Denmark, U.K., France, Italy, and Turkey). I assume it is cheaper than all of the European countries. While we complain about $3/gallon gas, a friend of mine in Italy is complaining about $10/gallon gas. Since gas is so cheap, there is no incentive for people in the U.S. to use the railroad, which even with the cheap tickets is still not much cheaper than driving. So, if ticket prices were increased to allow the rail to profit, nobody would want to ride. --Kainaw 20:21, 8 September 2006 (UTC)

What does "commercial viability" mean? I thought most non-US rail systems were government-subsidized... DMacks 20:37, 8 September 2006 (UTC)

Most rail systems are subsidised, as a lot of countries recognize the rail service not as a gold digging source of income for the government, but as a service, which the government helps provide, in exchange for all the taxes etc. Philc _TC 21:00, 8 September 2006 (UTC)

in NZ we privatised the railways, and if you ever wanted an example of why you don't privatise a natural monopoly, Tranz Rail is it (and NZ's privitised telecomunications service Telecom New Zealand too). Tranz rail ran the NZ railways into the ground, closing line after line due to poor maintanence, let alone the asset stripping. Xcomradex 23:03, 8 September 2006 (UTC)

In addition to all the above, consider the problem of distance. Railways in European countries and Japan don't have to cover particularly large areas. The United States, on the other hand, is gigantic, spreading across an entire continent. It costs a lot more to operate a train from New York to Los Angeles than it does to run one from London to Edinburgh. On top of that, the trip takes several days, which is unacceptable to most Americans when they can fly the same distance in five or six hours. (Not that anything operated by the government could ever attain profitability, but that's a separate issue.) --Aaron 23:16, 8 September 2006 (UTC)

High speed rail (such as maglev) could solve the time problem, especially between populus, close cities, like the Boston/New York/Wshington DC corridor. Of course, in these days of rampant terrorism, the high speed line would need to be well protected, as it would be a natural target. StuRat 05:06, 9 September 2006 (UTC)

Railways have to compete with other modes of transportation and those are subsidised, so the railways have to be subsidised too to keep the prices down. In the case of airplanes it's obvious - they don't have to pay tax over the fuel. And I have once heard that (in the Netherlands at least) car travel is also subsidised for about 50%. I just don't know any further details on this, but I suppose road building and maintenance with general public funds in stead of just taxes relatedc to car driving is an important aspect. I also once heard that if people had to pay the real cost of driving a car, no-one would. DirkvdM 13:49, 9 September 2006 (UTC)

Jet fuel is taxed in the U.S. with different cities having different rates. Rmhermen 23:28, 9 September 2006 (UTC)

Various economic booms in Japan really helped to boost the rail industry, allowing the national rail company (and later, numerous privatized rail companies) to extend, improve, and add numerous lines leading to remote areas of the country, as well as improve the Shinkansen (bullet train services). Now that the infrastructure has long been a staple of modern Japanese life, I doubt even a major depression could cause much harm to the rail industry. I also doubt that Japan would be able to achieve such a feat again if they had to start now. You can see effects of the rail industry "dealing" with recent economic pressure by the age of a lot of the trains (many of the trains run by private companies are very Art Nouveau).  freshofftheufoΓΛĿЌ  16:04, 9 September 2006 (UTC)

grasshopper

how do you tell the difference between a grasshopper and a cricket?Kevinamccracke 22:22, 8 September 2006 (UTC)

Color ? Grasshoppers are typically brown or green, while crickets are usually black. StuRat 00:55, 9 September 2006 (UTC)

Follow StuRat's links and read that grasshoppers have short antennae and crickets have long ones. I used to mix the two up in the naming of my photographs until I read those articles. DirkvdM 13:50, 9 September 2006 (UTC)

Length of Time To Circumnavigate Globe

I did a Misplaced Pages and Google search, but to no avail.

If I utilized only:

• 1) Public Airports/Airplanes (No Private Jets)
• 2) Automobiles
• 3) Trains, Subways, Chunnel, etc.,
• 4) Boats, and
• 5) Human Powered Vechicles (Bicycle, etc.)

What is the absolute minimum time it would take to circumnavigate the globe?

Thanks, --69.138.61.168 23:28, 8 September 2006 (UTC)

It'll make a major different depending where you're starting from, and how much of a 'straight line' you want to do... if you take a boat in summer, you could circumnavigate around the north pole in five minutes... if you want to stick within ten miles of the equator at all times, it'll take significantly longer. --Mnemeson 23:34, 8 September 2006 (UTC)

Ha! I didn't even think about taking a boat around the North Pole. Good answer!

It will need to be a submarine or icebreaker, because the surface of the water at the North Pole is covered with ice. StuRat 00:52, 9 September 2006 (UTC)

probably 48 hours by plane. JFK - Narita - Heathrow - JFK--69.138.61.168 23:40, 8 September 2006 (UTC)

I agree with 48 hours, by plane. The only time you would need any other form of transport would be to get from terminal to terminal in the airports. StuRat 01:09, 9 September 2006 (UTC)

It took me 24-28 hours to get from Orlando International Airport to Bangkok International Airport. — (talk) (Desk|Help me improve)

Of course a plane would be fastest. If you are required to stick within a certain distance of the equator, you probably wouldn't find commercial flights to suit you. But if the requirements are less strict, an eastbound plane would be faster than a westward bound one because it could hitch a ride on the jet stream. On top of that, it would cross the international date line (as Phileas Fogg found out) and gain a day (or lose one, depending on how you look at it). DirkvdM 14:11, 9 September 2006 (UTC)

I would assume they want to know the actual elapsed time, so don't care about time zones or the date line. StuRat 00:34, 10 September 2006 (UTC)

A quick check with kayak.com shows that it's not unreasonable to do this in 44 hours or less by commercial flights; one sample itinerary I found was (all times local):

• Leave London Heathrow at 12:30 PM, Thurs. Sept. 28; arrive Bangkok at 6:05 AM, Friday. (Thai Airways, Flt 911)
• Leave Bangkok at 7:30 AM Friday, arrive Tokyo Narita at 3:40 PM Friday. (All Nippon, Flt 5696)
• Leave Narita at 4:55 PM Friday, cross date line, arrive LAX 10:52 AM Friday. (All Nippon, Flt 7018)
• Leave LAX at 1:08 PM Friday, arrive back in Heathrow at 7:40 AM Saturday. (United, Flt 948)

You'd be arriving 43 hours, 10 minutes after you left; you'd have spent 38h, 14m on aircraft, and the trip would cost $5459 economy. And your luggage would wind up in Cleveland. Interestingly, the LHR-NRT-LAX-LHR itinerary, without the Bangkok stop, takes less time in the air (31 hours) but due to the connections, takes longer total. (And is $1000 more, not that that really matters.) --ByeByeBaby 19:25, 10 September 2006 (UTC)

September 9

Sandalwood characteristics

I am a hobbyist and would like to make a gavel out of sandalwood for presentation to a friend but I do not know if Sandalwood can stand knocking especially in a cold country. I have searched through the various relevant topics in Misplaced Pages as well as on the Internet, without success. Would appreciate some advice on this or some links from which I can obtain such information. Thank you. 218.186.8.12 01:54, 9 September 2006 (UTC)Kenneth Ang

Will your friend be using his gavel outdoors in the winter? In India, the government owns all Sandalwood trees, you'll have to deal with their infinite beaurocracatagcauauaucy to get your wood. Or, you could probably bribe someone.....

The friend in North America will be using the gavel during Lodge Meetings. Anyway if I have to go through endless beaurocracy just to get a piece of wood big enough to make a gavel, I'd rather not. All the same, it will be interesting to find out if Sandalwood will crack or split with constant knocking, as with gavels.

Mechanism of thermoception

What is the mechanism in which thermoception occurs? I remember it being "rapid coagulation of certain enzymes," to quote Dean Edell perhaps incorrectly or in the wrong context from my memory of two years ago. — (talk) (Desk|Help me improve)

That isn't really an accurate description. Research into mammalian thermosensation has advanced quite rapidly recently. Briefly, ion channels of the transient receptor potential (TRP) family, are found in the nerve endings of primary afferent fibers. When activated by a ligand that we perceive as hot (such as capsaicin) or cold (such as menthol) the channel opens and allows an influx of ions. This, in turn, causes an action potential which we interpret as "hot" or "cold". These same receptors appear to mediate the response to temperature itself also (as opposed to chemicals we perceive as hot or cold), though the exact mechanism of channel activation is currently unknown. TRP channels exhibit distinct thermal activation thresholds in mammals (>52 degrees C for TRPV2, >approximately 34-38 degrees C for TRPV3, >approximately 27-35 degrees C for TRPV4, <approximately 25-28 degrees C for TRPM8 and <17 degrees C for TRPA1). You can read more about this in the scholarly literature Rockpocket 06:04, 9 September 2006 (UTC)

The full text of Sven-Eric Jordt, David D McKemy and David Julius. Lessons from peppers and peppermint: the molecular logic of thermosensation Current Opinion in Neurobiology 2003, 13:487–492 is available on the net, and is a worthwhile review as a basis. Enzymes do not seem to be involved, nor any coagulation - in the ordinary "permanent" sense - unless the term "coagulation" was used rather unconventionally as a word to convey the idea of a (reversible) structural change in a protein. In that sense, temperature-related perturbation in protein structure, as opposed to chemical receptor interactions, may well be the basis for the ion channel changes, but details are lacking. Interestingly, we seem to have about 30 "coldness" nerves for every "warmth" nerve - why? --Seejyb 06:43, 9 September 2006 (UTC)

Dangerous Combination?

Hi, I would like to know please, if the Medications listed below, taken as a daily Regiment (45 Yr. Old Female) Pose any potential interactions, and or health risks? Any Feedback will be Greatly Appreciated. Thank You For Your Time And Concern.

Sincerely,
MmHm

• TEMAZEPAM
• TRAZADONE
• RITALIN
• LEXAPRO

• This is the kind of thing you should ask a doctor as indicated at the top of this page. - Mgm| 09:00, 9 September 2006 (UTC)

A pharmacist could also answer your question over the phone. BenC7 09:16, 9 September 2006 (UTC)

Well, they are all different classes of medications and it would probably depend on the doses and underlying illness. Certainly, any one of them could have serious side effects depending on how they are used and the individual taking them. If the Lexapro is taken for depression, the trazodone for sleep, the temazepam for anxiety, and the Ritalin for ADHD, and a person has all four problems, then it seems reasonable. However, one problem might occur if the Ritalin is being used to make a person more awake during the day while the trazodone is being used at the same time for sleep, then there are probably better ways to get this benefit. As you must understand, it's simply not possible for anyone here to know enough about the clinical situation you are involved in to competently give you an answer. In the end, the prescribing doctor(s) are your best source of information. InvictaHOG 10:10, 9 September 2006 (UTC)

As always, it's always best to consult with your physician, because all drug interactions must always be considered in the context of the individual patients' health profile. However, there is an online source for checking documented drug interactions-- use at your own risk: Check Interactions - DrugDigest--Mark Bornfeld DDS 13:32, 9 September 2006 (UTC)

Physics problem - not homework

I must be doing something wrong working out this problem:

A 1200kg car goes around a corner banked at an angle of 14° travelling at 80km/h. Is a friction force needed to keep the car on the road? If so, how much?

I am using the equations (tan θ = v/rg and F_centripetal=mv/r). Is there enough information in the question? BenC7 09:14, 9 September 2006 (UTC)

I would think the radius of the turn would also be needed, unless it cancels out in the calculations. StuRat 10:57, 9 September 2006 (UTC)

Assume a radius of 20m, another one of 200m, do the calcs, and if they aren't the same the problem is the problem, which it seems to be. --Seejyb 12:58, 9 September 2006 (UTC)

Our practical experience makes us worry that the car might go off the road to the outside of the corner. But in the artificial situation of no friction, the car could also slide off the road to the inside of the corner. Consider both possibilities. --Gerry Ashton 13:41, 9 September 2006 (UTC)

If you assume an infinite radius, the answer is yes, because the car would eventually slide down off the ramp. If you assume a very small radius, the answer is again yes, because the car would then immediately slide off the top edge. There needs to be a very specific radius for this question to make sense. I think? Maybe I'm being physically naive.  freshofftheufoΓΛĿЌ  15:25, 9 September 2006 (UTC)

To further explain my point: Since the answer is "yes" in both extreme situations, let's calculate the friction. Since a ramp with an infinite radius doesn't exert any force on a car that a straight ramp wouldn't, the amount of friction needed to keep it from sliding down is equal to the amount needed when the car is on the slope at stand-still. In case of a small radius, the only thing that you can calculate is that the amount of friction needed approaches infinity. The only other case to consider is the one where friction isn't required.  freshofftheufoΓΛĿЌ  15:31, 9 September 2006 (UTC)

Whether the track is banked or not, you still need the radius of the curve that the car is following.--Light current 21:15, 9 September 2006 (UTC)

Yes, but in that case, the answer is "yes" if the speed is over zero for every radius less than infinity.  freshofftheufoΓΛĿЌ  08:13, 10 September 2006 (UTC)

Although there is not enough information to say that the frictional force is x Newtons - we can work out a relationship showing how the frictional force varies as we change the radius of curvature. Use r = v / (g tan θ) to work out the limiting case where no friction applies - i.e. that the normal reaction force from the road surface is sufficient to both balance the object's weight, and accelerate the object with centripetal acceleration of v/r. For θ = 14º, g = 9.81 m/s, v = 22.22 m/s; r ~ 202 m. Lower than 202m and the object needs friction pointing up the slope, greater than 202m and the object needs friction pointing down the slope. By very rough back-of-the-envelope calcs (and I might have made a mistake), I think the frictional force is; F ~ 2848 - 575000/r F is in Newtons - and the positive direction is up the slope, r is in metres. Note that this is pretty approximate, and it's more accurate if you keep the thetas, m's, v's g's in the equation, rather than multiplying and simplifying as I've done. Note also, that if F = 0, the above equation gives r = 202m, as I had before.Richard B 21:10, 10 September 2006 (UTC)

cholesterol reducing spreads.

Hi, is it better to eat a cholesterol reducing spread (such as benecol) to lower your cholesterol level, or does the actual eating eating of the spread supply you with more cholesterol anyway so you are only reducing the cholesterol from the spread?

There are two cholesterol goals, keeping bad cholesterol low and good cholesterol high. Avoiding all cholesterol only handles the first part, while a product like Benecol has the potential to do both. StuRat 10:43, 9 September 2006 (UTC)

Flash cubes

Back when instant compact cameras were a novelty (mid-70s) some flash cube types required no battery but the camera was just shorting two leads connected to the respective cube face lamp. The lamps (behind the cube faces) contained a metal wool that ignited upon shorting the respective wires and produced the flash. I never understood the principle involved in igniting a ball of metal wool by shorting the wires leading into it. Anyone know?

I believe the "wool" was a flammable magnesium alloy which, when heated by the electrical current (like a filament), rapidly burned in the presence of oxygen from the air. This puts out a bright, but short-lived, flash of light. See flash (photography). StuRat 11:50, 9 September 2006 (UTC)

Is it possible that the battery was built into the film pack, so some people might not have noticed that the camera was equipped with a battery? --Gerry Ashton 13:43, 9 September 2006 (UTC)

There are a couple of related questions here; I'll take a stab at them.

First, it's actually remarkably easy to burn many metals under the right circumstances. A lot of metals are just waiting for a bit of activation energy so that they can oxidize. A nine-volt battery will easily and very rapidly heat a bit of wire from steel wool or a narrow strip of aluminum foil to incandescence and melting or oxidation. (Do be very careful if you try this one at home; small drops of molten metal are, obviously, dangerous.) Flash cubes contain lengths of very, very fine metal wire (typically some combination of the reactive metals magnesium and aluminum). When an electric current is supplied to the ends of the wire, it heats very rapidly due to its electrical resistance, to the point where the metal burns in a bright flash of light.

Conventional flash cubes, then, relied on a battery in the camera to supply that small spark of current that heated the wire in the cube to ignition. In the early 70s, battery-less flash cubes were introduced. Called Magicubes or X-Cubes, they relied on a piezoelectric crystal for their operation. When the flash was triggered, a tiny spring inside the flash was released mechanically; this spring drove a pin into a piezoelectric crystal, generating a pulse of current sufficient to ignite the flash. (It's very similar to the 'pushbutton' starters on modern gas barbecues.) These new contactless flash cubes were employed on cameras like the Kodak Pocket Instamatic 60; that linked web site has pictures of the cubes and an explanation of their function (scroll down).

I don't know of any flash cubes that were operated just by shorting the pins on the base of the cube; I agree with the original poster that such a setup seems unlikely to work (unless the flash cube contained an integral battery—something I've not heard of). The Magicubes had a mechanical trip (a little plunger extended up from the camera body into the cube to fire the flash) and lacked any electrical contacts. TenOfAllTrades(talk) 14:51, 9 September 2006 (UTC)

I've always wondered about that. I once bumped into someone in the dark (at a surprise party) causing a flash cube to fall to the floor and go off. Never knew how that was possible. Rmhermen 23:19, 9 September 2006 (UTC)

clicking rat

Hi, I have a small albino rat, about 7 weeks old. She seems to be quite healthy (I think) aside from the fact that she exhibits a nearly continuous "clicking" sound. At first, I thought it mighth just be tooth-clicking, which I've read is a sign of contentment in rats, but nowadays she does it almost all the time, with a frequency of around 1 Hz. I'm no longer sure the sound is coming from her teeth - it almost seems like it's correlated with her breathing. She is taking some antibiotics for another issue earlier on that seems to have cleared up (she was sneezing a lot - but she doesn't any more). Any ideas? Feel free to forgo suggestions that I go and take her to the vet. I probably will anyways - just wondering if anyone has any advice or experience in the matter. Thanks! -bmk

I had a hamster probably 10 years ago that seemed to do the same thing, though not all the time. I assumed it was tooth-clicking.  freshofftheufoΓΛĿЌ  15:20, 9 September 2006 (UTC)

Perhaps he is developing a knack for echo location. A news story on TV showed a high school student who lost all eyesight at age 3 who navigates by making clicks with his mouth. He could detect a garbage can on the sidewalk in front of him, find a door, or detect where a person was by echolocation. He also skateboarded. Albino rats have poor vision in general, do they not? Rats are supposed to be able to hear sound frequencies far higher than we can, and the short wavelengths would provide better spacial resolution. A click generates a wide range of frequencies. Or maybe the rat has a sinus condition. Edison 05:12, 11 September 2006 (UTC)

SI unit

Why people created SI unit ??

In short, to standardize scientific calculations. For more information see International System of Units, especially the history section. - Dammit 14:50, 9 September 2006 (UTC)

Originally, during the French Revolution, a new, rational, system of measurement was created to unify measures in France. (France previously had many provincial systems.) Then it became popular for calculations. Peter Grey 01:17, 10 September 2006 (UTC)

It's much simpler. For a further elaboration, see my standardised answer on my user page. DirkvdM 08:10, 10 September 2006 (UTC)

Is it possible to see the change history of a definition

Is it possible to see the change history of a definition — Preceding unsigned comment added by 64.142.81.252 (talk • contribs)

What do you mean by 'definition' Do you mean the lede para?--Light current 17:52, 9 September 2006 (UTC)

Or do you mean etymology? If so, you need an etymological dictionary.--Shantavira 19:21, 9 September 2006 (UTC)

Or do you mean the history of a Misplaced Pages article? Just click the 'history' tab at the top. DirkvdM 08:33, 10 September 2006 (UTC)

This is a language question. What you're talking about is semantic change. A word's changing definition is generally only observable when it's documented. In comparative studies, it is possible to see a change in meaning of different morphemes. The English word black is cognate with the Russian word for white. AEuSoes1 08:38, 10 September 2006 (UTC)

Copper tubing

And other large bore metal tubing. How is it made?--Light current 17:51, 9 September 2006 (UTC)

Some are extruded... a slug of metal is pushed through a die, which forms it into a circular shape. To make a hollow pipe, the die is in the shape of a hole with approximately the outer diameter of the pipe, and the die has a solid center with approximately the inner diameter of the pipe. And yes, if you're wondering what holds the center of the die in place, it is connected to the outer part of the die via a 'fin' of sorts. The metal being extruded through the die splits to pass around that fin, then re-joins and cold-welds together, making a hollow tube. Have a look at the article on Extrusion. 192.168.1.1 20:24, 9 September 2006 (Huh?)

THanks. I was wondering about the central part. I have heard stories about 'floating' internal dies as well. Also its this rejoining that I dont understand. For instance how does it work. THere are'ent any seams visible on the finished pipes!. How come?--Light current 21:54, 9 September 2006 (UTC)

If enough pressure is put on metal, is will cold weld to other metal. See the link for an explanation. StuRat 00:25, 10 September 2006 (UTC)

Also, some large diameter thin tubing may be formed as a long, flat sheet, which is then bent to form a tube, and welded at the seam. This method can be used for heating ducts, for example (although many of those are rectangular). StuRat 00:25, 10 September 2006 (UTC)

Why would I want to heat ducks? Oh ducts! 8-). Sorry straight face 8-|--Light current 00:31, 10 September 2006 (UTC)

Some people do prefer a nice Cold Duck. :-) StuRat 03:21, 10 September 2006 (UTC)

I need to see how the m/c works really. Must visit a pipe factory.--Light current 00:40, 10 September 2006 (UTC)

If you do, make a schematic and add it to the extrusion article. I also have difficulty visualising this. DirkvdM 08:37, 10 September 2006 (UTC)

West Nile Virus

is it a good strategy to infect myself with West Nile Virus now when I'm healthy and won't have anything more than a mild flu/cold from it? Then,I'll be immune FOREVERE! !! Jasbutal 20:31, 9 September 2006 (UTC)

Except for the part where you might die. No, it is not a good strategy. The best one would be to never contract West Nile fever. This way, you completely avoid the anorexia, nausea, vomiting, eye pain, headache, myalgia, diarrhea, rash, lymphadenopathy, and possibly, if it passes the blood-brain barrier, encephalitis, and spinal meningitis. Just not getting sick at all is the best "cure!" — (talk) (Desk|Help me improve)

what are you talking about!? No one between the ages of 20-60 years old dies of west nile unless they have a compromised immune system. The old and the young are the ones who die, with everyone else, you can barely even notice the symptoms. Jasbutal 20:55, 9 September 2006 (UTC)

The chances of you getting West Nile Virus are slim (depending on where you live), and I would take Mac Davis's advice and try not to get infected at all. And I don't think it's possible to get West Nile Virus on purpose...(?) —EdGl 00:08, 10 September 2006 (UTC)

There may be a low probability of dying from West Nile Disease if you are a healthy adult, but not a zero probability. So, it's a bad plan. StuRat 00:19, 10 September 2006 (UTC)

false. It's a bad plan if the probability of me dying later on in life from this virus doesn't outweigh the probability of me dying from it right now. Jasbutal 04:56, 10 September 2006 (UTC)

Ok, if you want to get into it further, you also have to assign a value to the intervening years, between dying now and when you are old with an impaired immune system. Also, there's a rather substantial probability that a cure will have been found before that happens. StuRat 09:54, 10 September 2006 (UTC)

Let's take an exaggerated example: you are currently 20 years old. If you voluntarily catch WNV now, you have a 40% chance of dying. If you don't, then you have a 50% chance of catching it involuntarily on your 60th birthday with a certainty of immediate death. Should you pass your 60th birthday, you will live until 80. What will you do? Of course, my figures are ridiculous, so feel free to come up with more accurate ones.-gadfium 05:56, 10 September 2006 (UTC)

Are you actually asking a question, or are you trying to educate RD?  freshofftheufoΓΛĿЌ  08:08, 10 September 2006 (UTC)

So I suppose the people who recommend against Jasbutal's vaccination idea also oppose the vaccination against small pox and other deadly diseases. After all, such vaccinations carry with them a small chance of dying. AEuSoes1 08:21, 10 September 2006 (UTC)

• You forget that the chance of dying from a vaccination is much lower than dying from the West Nile virus if you contract it. If I had to choose, I'd prefer the vaccin. - 87.209.70.231 14:12, 10 September 2006 (UTC)

heating my house

where can I find the prices of a btu of electricity vs a btu of natural gas (for whatever state)?

I want to do an analysis to see if it's cheaper to buy some space heaters and cut my gas service for this winter. Jasbutal 20:39, 9 September 2006 (UTC)

The prices vary from provider to provider, and since you don't seem to want to disclose a specific state, all we can do is estimate. Natural gas prices are certainly rising, and with the winter coming, heating costs are becoming more and more apparent. I'll do what I can to find some numbers for you, or maybe someone else might be able to answer first. --Russoc4 21:02, 9 September 2006 (UTC)

I should also add that forced air heaters and space heaters have different efficiencies when it comes to filling a house with heat. Space heaters are localized and are only intended for one room in use. Forced air heaters (usually) maintain the temperature in an entire house. --Russoc4 21:07, 9 September 2006 (UTC)

yea, I just wanted an approximation. I've got numbers now , just have to compute them: Jasbutal 21:12, 9 September 2006 (UTC)

http://www.eia.doe.gov/cneaf/electricity/epa/epat7p4.html

http://tonto.eia.doe.gov/dnav/ng/ng_sum_lsum_dcu_nus_m.htm

It's not worth it, by a big factor of 1.75 too. Jasbutal 21:21, 9 September 2006 (UTC)

electricity : $0.09/kwatthr = $0.09/(1000 J/s * 3600 s/hr * 1hr) = $2.5 * 10 ^ -8 per Joule

natural gas : $14.92/1000 ft^3 * 1 ft^3/1000 btu * 1Btu/1054.35J = $1.4 * 10 ^ -8 per Joule

Well, good job at figuring it out before us. Do try to refrain from using obscenities though. --Russoc4 21:26, 9 September 2006 (UTC)

sorry, I forgot this was the science desk Jasbutal 21:29, 9 September 2006 (UTC)

I am a bit confused about the 'obscenities,' as well as the somewhat seriousness of the comment. — (talk) (Desk|Help me improve)

it's a lot more casual over in Muskallaneous. Jasbutal 23:26, 9 September 2006 (UTC)

While it's quite true that it's more expensive to heat an entire home with electricity than with natural gas, there is another option: only heat the portion of the house you are actually using. Of course, you do need to heat the entire house enough to prevent the pipes from freezing, and I recommend using gas for this. However, if you only heat your bedroom to a comfortable temp at night, with an electric space heater, that should save you a fair amount of money. The daytime is trickier, as you're likely to move from room to room. However, you don't need to provide much heat to storage rooms. For most families, I'd think an automatic thermostat that turns the temp down to 40 at night, and up to 65 in the day, with supplemental heat from electric space heaters, might be the least expensive way to heat the home. The temp should also be turned down to 40 when everybody leaves the house for work or school. StuRat 00:00, 10 September 2006 (UTC)

There are also some safety issues with space heaters:

1) Don't ever use kerosene space heaters, they should be banned.

2) Don't let children use electric space heaters, as they can start a fire if paper is touched to the elements.

3) Get electric space heaters with tilt and overheat sensors, which turn off under those conditions.

4) Don't ever use a space heater with a frayed cord or a cord that overheats.

5) Don't ever run the cord under carpet, as that will allow heat to build up.

6) Make sure any extension cords are rated to handle the space heater's wattage (typically 1500 watts).

7) Place space heaters far from any flammable materials, like blankets.

StuRat 00:12, 10 September 2006 (UTC)

...and wear a hat. But coming back to the original question, the price per unit of energy should be shown on your utility bills. In the UK it has to be there by law.--Shantavira 08:19, 10 September 2006 (UTC)

Rats wanting to be held

According to the article Pet rat, pet rats often (or, at least sometimes) position themselves near the cage doors, wanting to be held by their human owners. Is there really any scientific proof for this? Is it likely that rats actually want to be held? Could there not be another reason for their behaviour (e.g. wanting to escape)? The article also says that some rats enjoy riding through the house sitting on their owner's shoulder. Is this idea proven? Perhaps the rats position themselves on the shoulders, merely being too afraid climbing on the sweater? In general, common belief and this article says (assumes?) that rats enjoy (human) social interaction: my general question, thus, is if this really is true, or if it is merely a human wish. --Andreas Rejbrand 21:10, 9 September 2006 (UTC)

The phrase is "wanting to be held", not "wanting to be hold". StuRat 23:42, 9 September 2006 (UTC)

• I suspect you haven't spent any time with rats. They are very affectionate, they distinguish between different people, they seek out pleasure (like high viewpoints giving them free rides). Now, obviously, one cannot scientifically prove they "want" anything, since rat-mind-readers aren't any more available than human ones are, but they certainly express what appear to be preferences. --jpgordon 21:31, 9 September 2006 (UTC)

Well, actually, I have spent quite some with pet rats (http://english.rejbrand.se/rejbrand/djur.asp). But yet I cannot say I am sure about the hypotheses. --Andreas Rejbrand 22:12, 9 September 2006 (UTC)

It is near impossible to "prove" anything about animal behaviour. You could ask, how do we know dogs actually enjoy human interaction? How do we know that them retreiving a ball or a frisbee is enjoyable, and that there is not another reason for their behaviour? The answer is that, when given an opportunity, behaviour without an obvious inherent biological purpose that animals freely choose to do is what we define as behaviour they "enjoy", based on the premise that that is what humans do. Whether there is another function for such behaviour is open to interpretation, in the same way human behaviour is. Consider why people go to the gym, play sport, or even have sex for enjoyment. The answer is: because our body rewards our brain with positive inputs in reponse to these activities. And this is because it makes evolutionary sense to reward and encourage behaviour that is constructive to survival and discourage behaviour that isn't. So if you take "enjoyment" in that context, it is clear rats do enjoy human interaction, but the reason for that is open to speculation. Rockpocket 22:32, 9 September 2006 (UTC)

Wanting to be held is a mammalian/bird thing, as the young of pretty much every species desire contact. Many "pet" mammals and birds retain this characteristic into adulthood. While this is mainly true of social species, some not-social species, like cats, also retain this characteristic. StuRat 23:47, 9 September 2006 (UTC)

Do you ever sit at your cage door, wanting to be held? (Someone had to ask.) DirkvdM 08:44, 10 September 2006 (UTC)

In my case, I really am just trying to escape. :-) StuRat 09:49, 10 September 2006 (UTC)

Similar questions could be asked about humans. Do they really want to go throught the same routine everyday (even every holiday for some)? Or do they just not know any better? DirkvdM 08:44, 10 September 2006 (UTC)

Let me rephrase my question slightly: does a rat sitting on a shoulder feel pleasure (as the article claims) or fear (e.g. of falling down)? Does a rat sitting near the cage door want to be held by a human, or does it want to escape? --Andreas Rejbrand 10:54, 10 September 2006 (UTC)

My reason for asking is merely that I want the best for my rats, combined with a bit of scientific interest. --Andreas Rejbrand 10:55, 10 September 2006 (UTC)

What they want might not be what's best for them. Suppose they want to escape. Would they be able to survive? They might have to compete with other (wild) rats and domesticated rats wouldn't stand a chance. If you want what is best for domesticated rats maybe you should not have bought them (if that's what you did), thus creating a demand for the breeding of more domesticated rats. Assuming they don't want to be kept in captivity, that is. But maybe they don't mind at all, if they don't know otherwise. That is actually quite probable. There is still the natural drive that all animals have. Look at how wild rats live and try to create circumstances that gives your rats an opportunity to live such a life. DirkvdM 13:33, 10 September 2006 (UTC)

True, indeed. Yet my original question has not been answered. In fact, I believe no human really know the answer. But the authors of the Fancy rat page must have learned these "facts" somewhere. --Andreas Rejbrand 16:27, 10 September 2006 (UTC)

I refer you to my answer above, it depends on how you define "pleasure". Most definitions are subjective in terms of animal behaviour ("gratification", "satisfation", "enjoyment") However, one definition is "one's will, desire, or choice". If the rats freely choose to ride on your shoulder - it is their choice - then we could say they make "make known their pleasure". Strictly we should no use terms such as these in describing animals, its a type of anthropomorphism. However, if we take our definitions of enjoyment/pleasure as i described above, then its not so innapropriate. Rockpocket 20:22, 10 September 2006 (UTC)

LED usage

Why did it take so long for LEDs to be used in traffic lights, road signs and for vehicle lights?--Light current 22:39, 9 September 2006 (UTC)

There must have been some change in the technology, as they now seem to be much brighter than they originally were. StuRat 23:30, 9 September 2006 (UTC)

Hi briteness LEDs have been available for some time (>10yrs) but its only recently I ve started seeing them used in these apps. Could it be to do with the cost?--Light current 00:08, 10 September 2006 (UTC)

Yes. Until recently, LED's in the specific colors required for traffic signals were extremely expensive. Both the reduction in manufacturing cost, and also the increase in utility (electric) costs have made LED signal faces very cost effective. Early LED's did not have the proper yellow and green colors to conform to the ITE standards. Also, a typical incandescent traffic light bulb is 160 watts. An LED face draws from 10 to 25 watts, making the return on investment much better. 192.168.1.1 01:01 10 September 2006 (UTC)

Whats ITE?--Light current 05:24, 10 September 2006 (UTC)

Suppose (a very rough estimate) that on average every 100 household neighbourhood has one intersection with 10 lights (four or more for the cars, same for pedestians and possbly some for cyclists). Suppose a saving of 100 W per light. That's 10 W per household. 24/7. A typical lightbulb comsumes 50W, about 20% of the time (at night). So it is an energy saving equivalent to one less lightbulb per house. Nothing big, but not bad either. DirkvdM 09:01, 10 September 2006 (UTC)

Lightcurrent: Sorry, I should have put that in. ITE = Institute of Transportation Engineers. www.ite.org

DirkvdM: Actually for the agency paying the bills, it is a huge savings. Given a typical intersection with three vehicle heads on each mast arm, for a total of 12 heads, and eight more pedestrian heads, there will always be 20 faces lit at any time. Traffic signals operate 24 hours a day. The energy savings is a pretty big deal, 160W x 20 versus 15W x 20. We're paying around ten cents per KWHour (if I recall correctly), and we've just slashed our operating cost to around a tenth of what it was with incandescent bulbs. Then there's the labor savings. Incandescent bulbs were regularly replaced in a formal re-lamping program. The LED faces will last for up to ten years without requiring re-lamping at all. My agency operates around eighty signals, so for us the decision to upgrade to LED's makes economic sense. --192.168.1.1 17:23 11 September 2006 (UTC)

Ah yes, any labour savings usually make a huge impact. But for the electricity cost my story wasn't all that different, except that I approached it from a differnt angle, not the total cost (for what area?) but the cost per household, which scales better (just multiplky by the numebr of households). Also you're talking about much bigger intersections, of which there aren't that many. So they sound inpressive but the more ubiquitous smaller intersections make a bigger diiference. That is a common mistake, to focus on the big things, but life consists more of the l;ittel things. Take the New York WTC attack. That made people fear terrorism, because thousands died. But because it was pretty much a one-off thing it's peanuts. Cars kill as many people in the US every few months. Every few months. And that's just the US. Worldwide the deathtoll is about half a million people per year. That is what people should fear, not terrorism. A common mistake, but a costly one. DirkvdM 17:34, 10 September 2006 (UTC)

The simplest intersection with pedestrian lights will have to have 8 of those plus 4 light for traffic so 12 lights total. (more than Dirk's 10, less than 192.'s 20.) But I don't think we can assume that intersections of two two-lane roads with traffic lights are the most common kind of lighted intersection as multi-lane roads are much more likely to have traffic lights. Rmhermen 03:21, 11 September 2006 (UTC)

First off, I should mention that I was reasoning from an Amsterdam perspective. For a city like Eindhoven, that is built for cars, it will be different. But in most places, the bigger the roads, the fewer there will be of them, so I suppose the calculation will be different but the outcome roughly the same. DirkvdM 08:15, 11 September 2006 (UTC)

Eye burns

How quickly do frostbite/heat burns dissipate when on the eye? Can you lose parts of it if you aren't careful? — (talk) (Desk|Help me improve)

Can you get frostbite in the eyes? maybe, if you splash cryogenic liquid in. --Light current 00:42, 10 September 2006 (UTC)

In Antarctica, as well as other places, it is so cold and dry I bet you can. I was thinking of LN2 actually. — (talk) (Desk|Help me improve)

I dont remember hearing of any of the Antarctic explorers getting frostbite in the eyes. Other parts of the body - yes. THe simple answer is to wear protective goggles when you pour it.--Light current 01:22, 10 September 2006 (UTC)

The skin around the eyes can certainly get frostbitten, but under extremely cold conditions your eyes will water profusely as a way (I must assume) to keep them from getting too cold and freezing over.  freshofftheufoΓΛĿЌ  08:03, 10 September 2006 (UTC)

The brain is always maintained at operating temperature, irrespective of how cold it is, because else you'd die. Maybe the eyes are so importatnt that they get the same treatment. Just a guess. DirkvdM 09:11, 10 September 2006 (UTC)

I suppose you could get a frostbitten eye by pouring liquid nitrogen on one. My suggestion: don't do that. Similar comment for putting a cigarette out in your eye, I suggest an ashtray, instead. StuRat 09:44, 10 September 2006 (UTC)

I must admit that what you say does sometimes make a lot of sense. DirkvdM 13:35, 10 September 2006 (UTC)

Though, I don't think real frostbite would actually occur with LN, because that takes time, and it is usually the result of the body slowly removing all blood from the region under extreme cold. You'd probably just freeze your eyes momentarily, and then they'd get all swollen and nasty.  freshofftheufoΓΛĿЌ  09:37, 11 September 2006 (UTC)

EMP's

why should I be worried about http://en.wikipedia.org/Electromagnetic_pulse ??

My PC is in a faraday cage, as is almost all important electronic equipment. right? Jasbutal 23:25, 9 September 2006 (UTC)

Well, an EMP could signify that a nuclear device has been detonated in the area, news of which... would probably worry me, I don't know about you though... --Mnemeson 23:29, 9 September 2006 (UTC)

You really don't need to worry about it, who told you that? — (talk) (Desk|Help me improve)

What about the wires into your PC-- are they filtered well enough to stand EMP?--Light current 00:09, 10 September 2006 (UTC)

you do all realize that if you bank with a modern corporation, your account is just a file on a computer...right? I'm not worried about money, or people, or nukes, or whatever, i'm worried about my dang money. Jasbutal 04:54, 10 September 2006 (UTC)

A communist's wet dream, an idea used in several films - wipe all banks clean and mankind will start with a clean slate. Any new money will have to be distributed evenly if there is no way anyone can prove how much money they had. I wonder if the same principle applies to companies and even nations. Of course rich countries have more and better production facilities and other physical goodies, so they can easily assume the top dog position again, but any differences in virtual property (money) will have disappeared. Right? Also, suppose not just money, but proof of ownership of a factory is deleted? Would that be possible and how migh ownership be distributed then? DirkvdM 09:19, 10 September 2006 (UTC)

you're scaring me dirk!! What can be done about the EMP threat!? back up everything on notarized papers? Jasbutal 18:25, 10 September 2006 (UTC)

That actually happened in the Soviet Union back in the 70s, I think it was. They massively revalued the ruble and introduced a new series of banknotes. People had to line up to exchange the old ones for the new ones, but they had to be able to explain how they had come by the old ones legitimately, otherwise they couldn't get the new ones, and the old ones became useless after a short while. Tough titties for a lot of people. JackofOz 21:04, 10 September 2006 (UTC)

Same in the EU with the introduction of the euro. If you wanted to exchange more than a certain amount of money (around the equivalent of 5.000 euro, I believe) you had to 'source it', so to say. A big blow to the bigger black marketeers. DirkvdM 08:18, 11 September 2006 (UTC)

September 10

Insect Costa Rica

• unknown Insect, Costa Rica, Tapanti National Parc
• unknown Insect, Costa Rica, Tapanti National Parc

These photos were taken at Costa Rica in march. It seems, one is male, the other female. On my mind, it's not a Parascopioricus. Does anyone know the name? --Ruestz 00:33, 10 September 2006 (UTC)

Phasmatodea? Great pictures by the way, we'll have to add them when we know for sure. — (talk) (Desk|Help me improve)

The LucidCentral Guide to Insect Orders is a useful tool for identifying insects to the order level. Unfortunately it doesn't go more specific than that. BenC7 01:32, 10 September 2006 (UTC)

What do snake eggs look like?

I found a partially burried pile of soft, white, oval shaped things on the ground in my yard a few days ago. The "shell" came off easily revealing a dry, yellow, oval shaped thing. Someone told me they were mushrooms but I doubted that. If they are snake eggs, is there any way to find out what kind? I live in North Carolina(eastern US) if it helps. --Isamil 00:47, 10 September 2006 (UTC)

Not a very specific answer I know, but: Some animals, including some snakes, have eggs with leathery or other not-so-hard materials for the shell, so snake eggs is a reasonable first guess. Peter Grey 01:11, 10 September 2006 (UTC)

More generally, reptile eggs are soft, so they could be turtle eggs or from some other reptile. StuRat 03:08, 10 September 2006 (UTC)

A Button mushroom could be mistaken for an egg. 1001001 04:01, 10 September 2006 (UTC)

Wouldn't a mushroom have a 'stem' and an egg not? Also, opening it should make it very clear, or don't you want to do that (or even pick it up)? DirkvdM 09:27, 10 September 2006 (UTC)

Don't open them, they could be endangered. If you really want to know, you could wait 'till it hatches (that would take a lot of waiting around though). I agree with people here though, it is probably a reptile of some sort. Were they in a hole or resting on the ground? Turtles and lizards generally create a hole or burrow for their eggs. --liquidGhoul 11:49, 10 September 2006 (UTC)

I can't remember ever seeing a turtle in this area. They were partially buried in mulch and were not in a hole. Tomarrow, I'l see if I can take a picture of them. --Isamil 23:25, 10 September 2006 (UTC) North Carolina has venomous snakes as well as harmless ones, so be sure not to stick them in a box under your bed and forget them. Edison 04:48, 11 September 2006 (UTC)

See http://wildwnc.org/natnotes/unearthly.html for info about snake egg clusters yu might find in North Carolina. This nature center in Buncombe County might be better able to advise you. Edison 05:02, 11 September 2006 (UTC) That helped, thanks. The article says no venomous sankes in this area lay eggs, so I suppose I'l just leave them there. Isamil 19:03, 11 September 2006 (UTC)

Salty Fish

Since lots of edible fish live in saltwater, why do the fish themselves not taste salty?--Light current 00:57, 10 September 2006 (UTC)

They don't? I think most of them taste salty to me. Anyway, the fish has a constantly active salt-getting-out system, because it would die if it had too much salt. — (talk) (Desk|Help me improve)

Though at the same time, the salt levels in their body are much higher than freshwater fish, which is why they die if put directly into freshwater.  freshofftheufoΓΛĿЌ  07:58, 10 September 2006 (UTC)

... because the inside and outside wouldn't be isotonic. The salty fish would absorb too much water and 'blow up'. Conversely, a sweet water fish in fresh water would shrivel. Few fish manage to migrate from one environment to the other, like salmon. I don't know how they do that, though, and the artiocle doesn't seem to say either (just skimmed through it). DirkvdM 09:31, 10 September 2006 (UTC)

The term is anadromous but clicking on that gets a bad article on fish migration, not any physical details. Rmhermen 02:58, 11 September 2006 (UTC)

So when these fish blow up, do we then call them bloaters?--Light current 10:25, 10 September 2006 (UTC)

How do I tell the difference between male and female gulls?

Anyone know? They all look the same to me. --84.65.209.240 01:11, 10 September 2006 (UTC)

Which particular sort of gull did you have in mind?--Light current 03:26, 10 September 2006 (UTC)

Bouys versus gulls?Edison 04:55, 10 September 2006 (UTC)

Some birds are very difficult to tell apart externally, though I'd bet in gulls there's some very specific (though relatively small) difference, e.g. beak color, color pattern, body frame. In order to tell the difference in cases where external inspection isn't reliable, blood or tissue samples may be required.  freshofftheufoΓΛĿЌ  07:56, 10 September 2006 (UTC)

More to the point, how do gulls themselves tell the difference?--Shantavira 08:30, 10 September 2006 (UTC)

Maybe they don't and just give it a try. Getting it right half the time should be sufficient to keep the species alive. Of course this would also mean that male gulls get butfucked a lot, but hey, if that's their thing. Some humans even like it. (Sorry about being such an open minded Dutchman again. :) ) DirkvdM 09:37, 10 September 2006 (UTC)

I'm no scientist but I'm guessing that the gulls themselves know their own sex... :) --Kurt Shaped Box 11:21, 10 September 2006 (UTC)

They look rather distinct to me. :-) StuRat 09:33, 10 September 2006 (UTC)

So they're distinguishable by the number of l's in their names? DirkvdM 09:41, 10 September 2006 (UTC)

What if they can't spel? DirkvdM 13:37, 10 September 2006 (UTC)

User:Freshgavin is correct - if you watch a breeding pair of gulls (herring gulls and GBB gulls at least) stood next to each other, 9 times out of 10, the male will be longer, wider and with a slightly bigger beak. It is very hard to tell sometimes though, unless you spend a lot of time watching them - and completely impossible when there's a big flock milling around. --Kurt Shaped Box 11:21, 10 September 2006 (UTC)

SPSS graph

Is it possible to do a histogram or bar chart with SPSS for a grouped frequency distribution table? -- Hersheysextra 01:35, 10 September 2006 (UTC)

Songs that break music theory rules

I was having a debate with my friend. He claims that music is a science, and that every song that sounds good in the world, follows the rules of musical theory. ie, every note is in the right key. Evry note is in perfect pitch. Now, I can't imagine that out of all the millions of songs in the world, there isn't at least one, that breaks at least one of these rules, while still being considered by at least some people, to be a good song. So, my request is, does anyone know any song like this? Personally, I have no knowledge of musical theory, but I do listen to a lot of music, and I think, music, like any art form, is subjective.--Richy 02:20, 10 September 2006 (UTC)

Depending on what era of music you live in, there are different rules. Depending on the culture you have different tastes. In the Far East, they like pentatonal systems, in the Middle Ages, Western harmony featured the perfect intervals of a fourth, a fifth, and an octave, and the rest were called "imperfect." Western tradition focuses on harmony and counterpointing, and in recent years we have grown to place attention on the melody of the song over whatever beat or chords might be playing in the "background." Think of a favorite rock song—you can probably remember the tune, but not necessarily followed the drummer's skills the whole song. — (talk) (Desk|Help me improve)

There are not very many music theory rules, and in fact the best music is often that which artfully bends the rules. Music that follows the 'rules' can be good, for instance some of the best rock and roll is perfect 4/4 time and uses only two or three chords. But some of the best pop songs go 'out of key' and time; Peter Gabriel's Solsbury Hill and Pink Floyd's Money (song) are both in 7/8 time; Michelle (song) by the Beatles, My Little Town by Paul Simon, and lots of other famous pop songs go 'out of key' (other than modulation, going up by a half-step for dramatic tension). He's not so well-known now, but perhaps the greatest songwriter of all time, Cole Porter, was very musically complex, going out of time and key all the time. And of course classical composers did it, Beethoven in the Presto movement of his Ninth Symphony, and all our favourite modern movie composers (the Imperial March, otherwise known as Darth Vader's theme, is a great example, as is a lot of Danny Elfman's stuff). Hope that helps. Also, another John Williams example is the Across the Stars love theme, which artfully changes key about 4 times. Anchoress 02:40, 10 September 2006 (UTC)

Who said 4/4 is better than, say, 6/8 (favorite of Elfman if I remember correctly), which is also "standard?" — (talk) (Desk|Help me improve)

I certainly didn't say that. But 5, 7, 11, etc are considered 'odd' times, unlike 2, 3, 4, 6, 8, etc. Anchoress 02:56, 10 September 2006 (UTC)

There are certainly conventions to music composition. They can and often are broken. Even the notes we define as notes (ie., what frequency we define a C to be, and so on) are not always followed, and not even in the Western oeuvre of music either. Dysprosia 07:54, 10 September 2006 (UTC)

About a century ago, some classical musicians decided that it was tome for 'out with the old an in with the new' because the rules were too strict (and indeed tehy were). But it was difficult to persuade composers to break with tradition, so they made new rules to replace the old ones. And some pretty stupid ones, leading to stuff like atonal music. I've heard some of it and it sounds like a pile of shite to me. DirkvdM 09:48, 10 September 2006 (UTC)

And those too were broken. Serial music has fallen somewhat out of fashion; focus these days seems to be on neotonality. Dysprosia 11:33, 10 September 2006 (UTC)

Not enough for there to be an article on it, though, it seems. DirkvdM 13:39, 10 September 2006 (UTC)

Of course, the absence of a Misplaced Pages article doesn't imply a lack of popularity in the real world; this is a whole other topic entirely. Dysprosia 02:36, 11 September 2006 (UTC)

If it were popular, wouldn't there have been at least a stub on it by now? Or are musicians underrepresented on Misplaced Pages? DirkvdM 08:21, 11 September 2006 (UTC)

To be brief on this (here is not the place to be discussing this point), it's probably for the same reason that Pokemon and other television shows are well documented while information on the arts is severely lacking. Dysprosia 03:55, 12 September 2006 (UTC)

As Anchoress already said, good art bends the rules. More precisely, it finds the right balance between following and breaking them. What the right balance is depends on the audience (or the artist, really). Some people prefer simple easy listening music. An extreme example is muzak, which is more a utility than art. At the other exteme you find exprimental jazz or atonal music, which I already mentioned. (btw, in pop music there is a differnce across the Atlantic, with US music being 'easier' and European music more experimental.) But there must be some rules. Take rhythm. It's usually 4 or 3 based (or multiples thereof) and occasionally you get 5 (or, rather, take 5 :) ). 7/8 is already weird, so making that work in an easy sounding pop song (as in Pink Floyd's 'Money') is a sign of sheer class. Flamenco uses some unusual rhythms too, eg 12 beat, but not quite - 3-3-2-2-2 (one, two, three - one, two, three - one, two - one, two - one, two). Indian (improvised) music seems to have very relaxed rules. I once heard a player say that if during a concert two players end up playing the same rhythm, that is a happy coincidence. I have spent about a year composing music and I like to bend the rules. One little peice I called 'blues without a rhythm', which is exactly what it is. Then agian, there is a constant hint of a rhythm, but it keeps on losing it and then finding it again, or another rhythm. If there were no hint of a rhythm at all, it would be cacaphony. But following the rhythm too precisely kills the music, a crime committed by most classical performers.

MacDavis already mentioned that almost all intervals were considered bad in the middle ages. Such as the third. Hell, you can't even make a major chord without that. Let alone a minor chord. And Mozart did something revolutionary when he used a seventh in a peice. Nowadays music that doesn't use that all the time would be considered dull. i once heard that the worst interval is the diminished fifth. So I decided to base a piece of music on it. But prettty soon I discovered that it was really based on the fifth, with the diminished fifth being a variaton of that, one that created tension that had to be resolved. And that last bit is very important. The rules are something you fall back upon, but it's the temporary deviation that makes the music interresting.

I could go on about this for a very long time. Music is the best combination of science (math) and feeling there is. It makes the basic human thought paterns (intelligence) explicit more than anything I can think of. DirkvdM 11:29, 10 September 2006 (UTC)

Listen to 'The Black Angel's Death Song' by The Velvet Underground. :) --Kurt Shaped Box 16:58, 10 September 2006 (UTC)

A few months ago, on NPR, they talked about music theorist Dmitri Tymoczko, who recently wrote a paper describing a new type of geometry he had created to represent music. There have been all kinds of music geometries to represent music, but none of them got it "all" right, but his apparently does. His paper was accepted to Science magazine, the first music theory paper they had ever published in 120+ years. In that paper, he says that Chopin's piano prelude in E-minor (Opus 28, No. 4) is the make-or-break song. Apparently most predictors indicate that song should sound like crap, but it sounds fairly good. Raul654 17:06, 10 September 2006 (UTC)

The wiki page on Time signatures talks about lots of the non-"standard" ones. DMacks 21:35, 11 September 2006 (UTC)

Interior Plains of the United States

My 4th grader need to research information regarding interior plains in the United States. We were able to obtain information on the wiki under great plains. We are lookin for answers on specific questions such as:

1. What forces of nature cause the interior plains of the United States to be formed or in other words, how did it develop> 2. What is unique about the interior plains? 3. What efforts are being made to preserve the inerior plains?

My 4ht grader went to the library and they do not have any materials in plains under landforms. Please help her.

Thank you very much.

This is an encylopedia, and you can just type in "Interior Plains" in the Find box in the left. Push go, and you're there. :) — (talk) (Desk|Help me improve)

The Geologic Story of The Great Plains will help with 1 and 2. On 3, there are U.S. Grants available for Conservation of the Great Plains 1001001 04:12, 10 September 2006 (UTC)

irrigation engineering

what are the types of irrigation systems?

See our page on irrigation--Light current 05:04, 10 September 2006 (UTC)

dynamic hermaphroditism

Okay, there are sequential hermaphrodites that change sex as part of their life cycle, and simultaneous hermaphrodites that have both sex organs; but is there such an organism that dynamically changes its own sex based on current population sex ratio, environment, available resources, etc. ? Phoenix-forgotten 05:37, 10 September 2006 (UTC)

There are cases of evolutionarily 'unintended' hermaphroditism caused by environmental stress such as polybromated diphenylsin polar bears. But I doubt this is what you were looking for.---Sluzzelin 11:23, 10 September 2006 (UTC)

Sure. alteripse 11:29, 10 September 2006 (UTC)

Cell phone batteries

Is it true that if your current cell phone you use breaks and it is not repairible that the battery can be placed in another phone and all your data remains or is saved on the new phone.--Biggie 05:49, 10 September 2006 (UTC)

No, batteries have no capability of storing information in such a way. Even if there was a battery that was for some reason attatched to a memory chip, it would probably only work in the exact model of phone that it was constructed for.  freshofftheufoΓΛĿЌ  07:49, 10 September 2006 (UTC)

Battery, no. SIM card, yes, to some extent. Phones permit you to save data on the SIM card, which can easily be transferred. Dysprosia 07:54, 10 September 2006 (UTC)

Thanks for the info--Biggie 08:49, 10 September 2006 (UTC)

Battiers just provide power to the phone. --Proficient 06:15, 11 September 2006 (UTC)

An amp's power consumption

Suppose I have a 100W amp. Does it draw 100W all the time? Or does that depend on how far I turn the volume up? Or even how loud the music is (the dynamics of the music)? I suppose the former but not the latter. If I set it at half the maximum volume, measured by subjective perception (it sounds half as loud). Is the power consumption then half of what it would be at maximum volume (so 50W). I'm pretty sure not (much less), but what is it then? DirkvdM 09:08, 10 September 2006 (UTC)

Yea, that's the maximum. Whether you reach the max would depend on both the volume of the recording and the volume setting on the amp. StuRat 09:13, 10 September 2006 (UTC)

If its class A, yes it will draw constant power wasting whatever doesnt go into the speaker. But if class AB (which has a max efficiency of 78.5%), then the power consumption is almost proportional to the power in the speakers (and hence the volume). In a class AB amp, there will be some constant power dissipation not related to the output power, but this will only be a few watts at most. See electronic amplifier--Light current 09:23, 10 September 2006 (UTC)

THe question of efficiency vs output power, Im not certain of.--Light current 09:43, 10 September 2006 (UTC)

In general electronic equipment may draw far more electricity than its rated output. High fidelity is a bigger goal with audio than efficiency. Any heat given off is the result of that inefficiency.Edison 19:29, 10 September 2006 (UTC)

gravitational waves and propulsion

Im aware that none of the machines that claim to produce these waves have been varified, but they exist right? What is the mainstream physics communities views on gravitational waves being used for propulsion or moving objects in the future? and are these the waves produced by gravitoelectromagnetism?

Robin

Well, gravitational radiation is produced whenever a mass accelerates, but for everyday masses and accelerations the waves are unobservably small. To produce enough gravitational radiation to detect, you need huge masses accelerating very fast, like binary neutron stars spiraling towards each other. (The reason they spiral towards each other instead of staying in a stable orbit is exactly because they emit gravitational radiation.) I did find a paper with the exciting title Gravitational radiation and its application to space travel, but it's all theoretical so far. —Keenan Pepper 16:18, 10 September 2006 (UTC)

Keenan Pepper is absolutely right about the mechanisms behind gravitational radiation although it's probably worth pointing out that motion in a circle is acceleration (lay-people, particularly argumentative ones, sometimes disagree with this). I haven't read the paper, but I can't imagine gravitational radiation being terrible useful for space travel as it is really rather weak. If it were to be harnessed then the first step would be to use it to transmit information. Its real worth will be (at least initially) for observation as it will allow us to see back into the radiation dominated period of the Universe.

We're out of transcluded pages

So, what happens now? Do we just delete old posts?--205.188.116.74 13:56, 10 September 2006 (UTC)

• Erm, I'm not sure I get what you mean. If you mean you can't transclude more templates than we have right now, we just archive the oldest day (it may even be done automatically), but I don't think we're out of transcluded pages. The max. limit was raised, and I doubt we hit it. - 87.209.70.231 14:05, 10 September 2006 (UTC)

• I believe he means that none of the Ref Desk pages currently include any transcluded pages pointing to archive pages. In this case, instead of just removing the transclusion, we need to first create the archive page, then remove the day from here. I believe this will need to be done manually, as the bot that did this is no longer running. StuRat 00:10, 11 September 2006 (UTC)

Sexual Advice

Que: Can a curved penis be made straight with the help of surgery? — Preceding unsigned comment added by 59.144.180.72 (talk • contribs)

Probably, but we can't do that here on the desk. Take it to see a doctor.--Shantavira 16:43, 10 September 2006 (UTC)

I think so. Is it really worth the pain, hassle and expense though? Supposedly most men's cocks bend either to the right or left when erect. How 'curved' are we talking about? --Kurt Shaped Box 16:55, 10 September 2006 (UTC)

Apparently bent ones offer a better experience for the woman... obviously not to bent... but yeh, anyway, you may just be being to self conscious. Philc _TC 17:26, 10 September 2006 (UTC)

• Penises are rarely straight; they don't need to be for good sex. I wouldn't worry about it. If you do, bring it up with your doctor. He's the only one who can decide if surgery can be done and if it is needed. - Mgm| 19:46, 10 September 2006 (UTC)

if it's needed!? are you kidding me I'll get surgery if I damn well want it and can pay the money for it. Jasbutal 21:10, 10 September 2006 (UTC)

Youd be surprised, doctors do have the right to refuse to perform surgery you know, their not legally bound to straighten your penis on demand you know. Ususally you wont even know if they have refused, because they would have just had a few sessions with you, and chatted about what you want done, and by the end of it convinced you that you dont want surgery, because usually they're right. Philc _TC 21:44, 10 September 2006 (UTC)

let's just get something straight. The guild-like AMA and all member doctors chose their profession for the respect and the money. Trust me, you offer the money and you'll be able to find an AMA doc to do it for you. Jasbutal 04:44, 11 September 2006 (UTC)

Guys, we tell our ref desk clients to seek appropriate professional advice about medical, dental, or legal matters. That means that we shouldn't be entering into debates about the merits or otherwise of such surgical procedures. Shantavira's reply was the perfect one. IMO, everything since then has been inappropriate. JackofOz 01:35, 11 September 2006 (UTC)

Wow. I didn't know that. --Proficient 06:16, 11 September 2006 (UTC)

Anyone with half a brain should understand that this is not a medical ref desk. If you get an expert reply you're lucky. Most answers will be educated guesses that might point you in the right direction. By your reasoning we shouldn't have any medical articles either, unless it has been established beyond doubt that the autors are true experts on the subject at hand. DirkvdM 08:32, 11 September 2006 (UTC)

I agree. You don't have to be a man interested in straightening his curved penis to be curious about whether curved penises can be straightened. It's an encyclopedic question, so it's within our domain. We should always be careful to remind people that we're no substitute for doctors, but as long as we do that, I think we should feel free to try to figure out answers. --Allen 08:54, 11 September 2006 (UTC)

What I'm talking about is practising what we preach. People often get abused around here when they ask a question without first doing a search. I don't agree with the abuse part of it, but the central issue is that there are guidelines that questioners are asked to read and abide by. Fair enough. Well, guidelines work both ways. The other side of the coin is that we can hardly ask them not to expect medical, legal or dental advice here, if we in fact tender such advice in response to a question. Every time we break our own rules, we undermine our credibility. That's my main concern here. JackofOz 07:28, 12 September 2006 (UTC)

Check out Peyronie's disease. Also do a web search. 68.183.136.15 01:44, 13 September 2006 (UTC)

Curvature of space and time

What is the simplest way to understand the concept of space-time and its curvature?

the ? varible is part of the experiment that is affected by the independent varible.

 if you could help please. thank tou

Think of it in terms of a man's penis - supposedly most men's cocks bend either to the right or left when erect. I think space-time curves in the same manner. (sorry, that was a silly answer - but I couldn't resist) --Kurt Shaped Box 17:02, 10 September 2006 (UTC)

Well the ubiqutius explanation of general relativity is probably found at the article. It concerns a latex sheet representing the spacetime continum, and masses bend the sheet, curving it, and that is a gravitational field. — (talk) (Desk|Help me improve)

The rubber sheet is an reasonable simplification - as with most concepts of curvature in three (spatial) dimensions removing a dimension helps people to visualise it. As an undergraduate, one of my professors told me that to visualise the curvature in three dimensions is impossible. However, I find visualising a gravitating body as stretching spacetime by pulling it towards it (pulling more strongly nearer the body and less further away - inverse square law) makes for an acceptable visualisation. I justify this by imagining a triangle being stretched in just such a manner - the internal angles will equal less than 180˚ - demonstrating just such an hyperbolic geometry as is associated with a gravitating body.

For most people it is not possible to visualize the three dimensional negative curvature, but it is better to do that if you can. I *think* the easiest two ways (I have made them myself and never told anybody before) are to imagine the flat sheet, and one that is perpendicular, along the z axis. Stick Earth right inside that corner, and see the dip. Or you could imagine something like the Earth as a spikey ball, and the (hollow) spikes being like a tangible gravitational field. Kind of like sticking your finger into the Earth and the paper turning into the shape of your finger, flairing at the edges. — (talk) (Desk|Help me improve)

I'm not sure what the advantage of having two sheets is over the single sheet - having two sheets is still a two dimensional representation just with a fold. A complication which, to me, doesn't have any advantages. As for the 'spiky ball' explanation, I have never heard of anything like that for explaining curvature and I'm not really sure what you're getting at with it (this is not a criticism). In my experience, the problem most lay-people have with visualising curvature in three dimensions is that they don't try to think of it in terms of the geometrical properties of the curvature.

Direct gene transfer using PEG and Calcium chloride

Sir/ Madam,

I will be benefitted if I get more information regarding and related to this subeject.

We don't seem to have an article on your meaning of PEG, and Calcium chloride has just a couple of sentences: "Aqueous Calcium Chloride is used in genetic transformation of cells by increasing the cell membrane permeability. This allows DNA fragments to enter the cell more readily." The reference isn't given. Melchoir 21:30, 10 September 2006 (UTC)

The PEG in this case is polyethylene glycol, linked from the dab page at PEG. What the original poster really needs here is either a good laboratory manual that describes the process in detail, or (ideally) a local colleague who has experience with transfections and can provide a protocol. TenOfAllTrades(talk) 21:45, 10 September 2006 (UTC)

Ah, I was thinking PEG would be a three-word name of a technique. Melchoir 21:47, 10 September 2006 (UTC)

Helium Balloon questions

1. What would a helium balloon do in gravity-less outer space?

2. What ratio of regular air to helium should go in a balloon so that it floats in the air stationary? Thanks! Reywas92 17:45, 10 September 2006 (UTC)

1. Unless it was quite strong, it would burst (without a bang).

2. It doesn't matter. Assuming it gets off the ground it will eventually reach an altitude at which its weight is balanced by its reduced lift in the rarefied air.--Shantavira 18:19, 10 September 2006 (UTC)

A helium balloon in space would inflate to the same size as on earth if the pressure differential were the same between the inside and outside. So if atmospheric pressure is 14.7 pounds per square inch or 101.325 kPa, and the balloon inflates to 1 foot diameter on earth, in space for it to inflate to 1 foot the internal pressure would have to be reduced by 14.7 PSI. Now consider temperature: if the balloon is in the shade, it will radiate off heat, become cool, and shrink. The pressure would decrease in proportion to the drop in absolute temperature, PV=nRT per the Gas laws. If the balloon is in the sun, it would heat up and expand. If it were in the International Space Station or the Space Shuttle, it would drift with air currents, with no particular tendency to rise to the ceiling or sink to the floor, since these surfaces would be interchangeable. If you untied the stem and let the helium spurt out, it would take off like a rocket, since Newton's Third Law says To every action (force applied) there is an equal but opposite reaction. The lack of a surrounding atmosphere for the balloon exhaust to "push against" would not invalidate this law. If you stuck a pin in it, it would burst, but silently,since there is no air to transmit sound. Echo 1 (seeEcho satellite) was a plastic mylar balloon put in space as a passive communication satellite in 1960 which lasted until 1968. 100 feet across, it was easily seen with the naked eye when in the right portion of the night sky to reflect sunlight. It can be seen at http://www.scienceandsociety.co.uk/results.asp?image=10300344&wwwflag=2&imagepos=1 No info on whether it was inflated with hydrogen or another gas, but a gas with larger molecules might not have diffused out through the skin as fast.Edison 19:53, 10 September 2006 (UTC)

It all depends on how big the ballon is, as its area (i.e. the weight of the skin of the balloon) goes up in squares, while the capacity cubes. So there is no one answer, though a formula could probably be concucted. Philc _TC 21:52, 10 September 2006 (UTC)

Question about Sinusitis

I've had sinusitis before (eleven times in one year, at one point) and I'm fairly sure that it's not contagious, but I'd just like some verification, because this could be old information. Is sinusitis contagious, and if so, how contagious is it? Thanks in advance!! Srose (talk) 19:01, 10 September 2006 (UTC)

Contagiousness relates to spread of a disease from one person to another. Sinisitis can be infectious, but results mostly from bacteria already resident in the sinuses rather than "caught" from other people. You need to ask your physician what is causing you to have chronic sinusitis and what can be done about it. - Nunh-huh 19:16, 10 September 2006 (UTC)

Get your medical advice from a physician. 11 time in a year is way too much. See an Eye Ear Nose and Throat specialist. But from personal experience, there may be things he can do to alleviate the condition. Sinusitis can lead to some very bad things, such as meningitis.Edison 19:56, 10 September 2006 (UTC)

Thank you both very much! I've replied on your respective talk pages. I do get most of my advice from my physician and the specialists that I see, but of course they're unable to answer questions on a Sunday! :) Anyway, I'll repeat myself and say: thank you very much! Srose (talk) 22:20, 10 September 2006 (UTC)

If you have an allergic or autoimmune form of sinusitis, then it's not contagious, but it may be if you have a fungal, viral, or bacterial form. StuRat 23:28, 10 September 2006 (UTC)

See a pulmonary or ear/nose/throat doctor. If we start giving advice it will include some unpleasant possibilities. alteripse 00:36, 11 September 2006 (UTC)

What is insect hair largely composed of?

I know mammals have hair composed mostly of keratin. Many insects, like this moth, also have hair. Is it made of chitin, or some other substance? Gary 19:10, 10 September 2006 (UTC)

It's chitin. - Nunh-huh 19:12, 10 September 2006 (UTC)

Thanks! Do you have a source, by any chance? Gary 02:53, 11 September 2006 (UTC)

Here is one — (talk) (Desk|Help me improve)

How to tell if watermelons are ready to harvest?

I have this year learnt how to grow plants from seed. For fun I bought a packet of melon seeds and planted them in pots - I do not remember how long ago. I have three green melons about four or five inches in diameter.

How can I tell when I should harvest them please? As I am in the UK they may not grow as large as the watermelons for sale in supermarkets, as the latitude (or maybe I mean longitude?) here is about the same as Newfoundland and hence the sun is not as powerful.

As I noticed that something had eaten into the rind of one of them, I did cut that off the stalk and sliced it open and ate it. I realised it was a watermelon. It was pink inside with seeds, and was moderately sweet. So now I've got two left. Will they grow any more or should I harvest them now?

If the first watermelon seemed ripe, I'd harvest the other two right now, especially since it seems they may be eaten by something, if you wait. StuRat 23:22, 10 September 2006 (UTC)

If you don't harvest them in time, they reportedly become vampire watermelons. Be careful. alteripse 02:28, 11 September 2006 (UTC)

The ones we grew were way bigger than what you described, so may be a different type. You can tell when a melon is ripe by thumping it with your knuckle. An unripe watermelon, not yet red or sweet will have a relatively high pitched clear sounding thump. A ripe watermelon will have a dull and lower-pitched thump, probably due to the appearance of cracks in the interior or to the higher sugar content. If there are smaller and greener melons, these will grow and ripen unless the temperatures have dropped. Melons ripen best on hot days with full sun. If the vines and leaves look brown and dead I would not expect any more ripening. They will eventually rot if not picked when ripe. I do not believe they continue to ripen after picking. They can be stored for days in a refrigrator. Enjoy!Edison 04:42, 11 September 2006 (UTC)

According to my cooperative extension, besides the thumping sound, a ripe watermelon can be distinguished by "a buttery-yellow color of the soil where the fruit rests on the ground." --Ginkgo100 04:48, 11 September 2006 (UTC)

That thumping experiment seems nice. But if you already have you're melons ripe, what can you use as reference to whether it's dull or high pitched? --Proficient 06:19, 11 September 2006 (UTC)

• Smell the water melon at its 'butt end'. A ripe one will have the very noticeble sweet scent (slightly alcoholic in some types). - 131.211.210.11 07:33, 11 September 2006 (UTC)

Are full moons always in the east?

Recently I was driving home at dusk and was surprised to see the sun sinking in the east. I thought I'd taken a wrong turn. It was a few minutes before I realised I was not looking at the sun sinking, but at a bright full moon rising.

This made me think - as the sun had just gone under the horizon in the west, then it was in the right position to shine full-on the moon in the east.

So are full moons always seen in the east, half-moons in the north or south, and new moons in the west?

And would some extra-clever person be able to calculate from the astronomical data I have given where I was in the world, or what date it was? 81.104.12.47 21:21, 10 September 2006 (UTC)

That sounds about right, if you mean where the moon is just after sunset. Seems to me that the full moon would also set in the west just before sunrise. Melchoir 21:27, 10 September 2006 (UTC)

Yes, why couldn't you have a full moon in the west at sunrise or a full moon in the center of the sky at midnight ? StuRat 23:12, 10 September 2006 (UTC)

Earlier this week I saw a huge full moon rise in the east and move across the sky to the west. It set in the west. This happened because the earth rotates. Half or quarter moons behave the same way. Edison 04:34, 11 September 2006 (UTC)

What I was going to say. See lunar cycle. A full moon is always "opposite" the sun (that is, 180° away from it in the 360° sphere of the sky), while a new moon is always very near the sun. You're more likely to see a thin crescent during the day than at night. --Ginkgo100 04:51, 11 September 2006 (UTC)

Full moons are more usually seen in the east merely because that's the time and place where they attract attention, i.e. just after dusk and near the horizon. But then they rise and culminate around midnight and set in the west in the early morning. And no, it would not be possible to calculate your position from that information alone. The moon appears full on the same night everywhere, and always rises in a generally eastern direction (anywhere between NE and SE depending on the time of year.)--Shantavira 07:56, 11 September 2006 (UTC)

Chocolate allergy?

Hey all. Several years ago I noticed that eating chocolate would cause me to sneeze, usually only once or twice, within a minute or so of consumption. For a while now I've wondered what it is that is actually causing me to sneeze. I had a theory that how much I sneezed was dependant on the richness of the chocolate, but I can't say I've conclusively proven that. I assume this is an unusual case seeing as Misplaced Pages's allergy page makes no mention of sneezing or chocolate. Anyway, some answers please:

• Any suggestions on what precisely within the chocolate is causing the reaction?
• How unusual is it to a) have such a consistent mild reaction to something and b) to something as unusual (in terms of being allergic to) as chocolate?

Oh, and for the record, I am male, 17 years of age, and have eaten chocolate throughout my entire life. Hammer Raccoon 21:25, 10 September 2006 (UTC)

Are you allergic to chocolate? A true chocolate or cocoa allergy is rare.  --Lambiam 22:05, 10 September 2006 (UTC)

Also Photic sneeze reflex MeltBanana 22:30, 10 September 2006 (UTC)

It may not be the chocolate itself, but something else in it. Many chocolates say "processed with alkali", for example. StuRat 23:06, 10 September 2006 (UTC)

Indeed. You may be allergic to an ingredient like a preservative. --Proficient 06:20, 11 September 2006 (UTC)

But surely if I was allergic to something like a preservative then other foods that use that preservative would also cause me to sneeze. Hammer Raccoon 15:14, 11 September 2006 (UTC)

Is it a particular brand or type of chocolate that causes this reaction, or all chocolate? Are there different levels of severity? User:Zoe|(talk) 17:08, 11 September 2006 (UTC)

The brand doesn't seem to affect it. And severity is usually the same, a couple of sneezes and that's it. Hammer Raccoon 15:55, 12 September 2006 (UTC)

Satallites in orbit

How many satallite are there in orbit at any given time? how many man-made spacecraft in total are there out there in space?

If you've got a few minutes, you can count all the ones being tracked on this site, though there's also few more US spy satellites not on that list.

Their master index appears to have 1198 entries (not counting the space shuttle and the space station). These would probably be most of the functional non-military satellites. Rmhermen 02:51, 11 September 2006 (UTC)

On top of that, you could have a look at our list of unmanned spacecraft by program to add some of the ones not in Earth orbit, such as the Voyager program, a few of the Pioneer program spacecraft (including one nearly 40 years old that still works and is contacted periodically), and the various others. --Robert Merkel 01:39, 11 September 2006 (UTC)

Pioneer 10 and 11 are both dead. But there are a number of other active missions to Mars, the Sun, Pluto, etc. A number of satellites still in orbit are dead, either in parking orbits or just not yet fallen back to Earth. (Vanguard 1, launched in 1958 but dead since 1964, is the oldest satellite still in orbit.) Rmhermen 02:40, 11 September 2006 (UTC)

But Pioneer 6 is probably still alive (nobody's called to check for a while). Pretty amazing gadget, that. --Robert Merkel 04:20, 11 September 2006 (UTC)

6Q0B44E is a recently discovered satellite in earth orbit a couple of times the moon's distance out. It is suspected to be a Saturn booster from the Apollo programs which was lost in space for 30 years or so then wandered back into earth orbit circa 2001. Ironic?Edison 04:30, 11 September 2006 (UTC)

Interesting. thanx for the informations guys! i never realized the number is in 4 digits!

also, why are there so many dead ones? why doesnt the owner just blast them outwards from our solar system? it wouldnt be as harmful to polute the rest of the galaxy instead of our own solar system. plus, doesnt it get too crowded? have any two satallites ever collided?

Escaping from the solar system requires a lot of fuel and is therefore expensive. It's much better to force the satellite into Earth's atmosphere and have it burn up. Also, space is huge, and a few thousand satellites aren't going to do much. (Imagine if there were only a few thousand people on Earth's surface. And Earth's surface is two dimensional, while satellites can move in all three dimensions.) --Bowlhover 20:02, 12 September 2006 (UTC)

Is this how to convert moles to grams?

Say you had a mole of Iron. It'd be the same as having 56 grams of it, right? Or if you had three moles of Sulfur, it would be 96 grams. Am I correct? --GUTTERTAHAH 21:42, 10 September 2006 (UTC)

You are very definitely on the right track! Mass = moles x (formula mass). --G N Frykman 21:45, 10 September 2006 (UTC)

Well yeh your right to the level of accuracy you have given your numbers, so yeh. Philc _TC 21:46, 10 September 2006 (UTC)

Ah, good. That's one thing about chemistry I won't screw up <_< Thanks a lot! --GUTTERTAHAH 21:50, 10 September 2006 (UTC)

And if you have a molecule instead of a monatomic element, then you need to add up the atomic weights of each atom in the molecule. So for H2O, you would add the weight of two hydrogens and one oxygen, to get the molecular weight. This molecular weight is then multiplied by the number of moles to get the number of grams. StuRat 22:58, 10 September 2006 (UTC)

Ugh, good luck with moles. I never could understand those in Chemistry. 172.166.8.176 02:34, 11 September 2006 (UTC)

It's much better to deal with them in Biology. There, you can convert them to grams just by putting them on a scale. --Serie 22:31, 11 September 2006 (UTC)

Real Talking Animals

Is the possibility of animals creating their own language in the next 100,000 years possible? Besides barking or meowing etc... or the fact that some birds were trained to talk. This may be more of an opinion question unless some theories have already been created by scientists. -MF14

Depending on what you call a language, many animals already have one. Despite its own opening sentence, Animal language describes a few of these. Animal communication is another related, broader article. Melchoir 23:26, 10 September 2006 (UTC)

Yes, animals already have a "language", it's just very primitive by human standards. They can manage to tell each other when they are angry, horny, hurt, etc. Communication within each species is the clearest, but interspecies communication is common, as well. You generally know what your dog or cat wants, don't you ? However, if you expect to have a discussion with your cat on the tenets of existentialism, forget it. It's not that the communication is limited, it's that they can't understand any of those concepts, as they lack basic "symbolic logic" and any potential for abstract thought. StuRat 00:03, 11 September 2006 (UTC)

All sorts of things are possible over the course of 100 000 years, but while animals have means of communication, none of them (except bees) currently appear to have anything ressembling the human language faculty, which combines abstraction, symbols independent of external stimulus, and grammatical structures for building complex representations out of symbols. Scientists aren't completely sure about all the issues, but human language is not simply a more complex form of animal communication, so it's not clear there would be any reason for another species to evolve the ability. Peter Grey 02:00, 11 September 2006 (UTC)

A relativist's observation: human language is probably pretty primitive by, say, platypus standards. They probably think humans are pretty dumb because we cannot communicate about the things that matter to them. (And don't ask me what those are because I am only human). Platypuses learning human language is as (un)likely as humans learning platypus language. DirkvdM 08:44, 11 September 2006 (UTC)

I don't think that's true. A platypus is not cognatically capable of wondering if the "platypus language may possibly look primitive by human standards", and thus, is more primitive. Humans are much more likely to learn platypus language than platypi are ours, because we can observe them and create models to mimic their behavior.  freshofftheufoΓΛĿЌ  09:12, 11 September 2006 (UTC)

How do you know? We're humans (a fair assumption :) ), so we cannot know how platypuses reason. We'd have to be platypuses for that. Even as a kid I always found the question "what animal would you like to be?" stupid. I'd have to be the animal to know what it is like to be that animal, but even if that were possible then I wouldn't know what it would be like to be another animal (or a human for that matter), so I still couldn't make the comparison. Your reasoning is the basis of xenophobia - they're different, therefore they are inferior. DirkvdM 09:01, 12 September 2006 (UTC)

I'm no expert but I do spend a lot of time watching gulls and corvids and to me, it certainly seems that they have a language - a fairly complex one too. As well as the various vocalizations, there seems to be an aspect of body language used to modify the meaning of various utterances. Seriously, just watch two (non-aggressive) herring gulls communicating sometime - it's like some strange choreographed dance. --Kurt Shaped Box 14:30, 12 September 2006 (UTC)

what plant is this

The top one is a stem with some berry looking things and the bottom one is a stem that is more mature, I suppose. schyler 23:44, 10 September 2006 (UTC)

What part of the world did you find it in? Gary 02:35, 11 September 2006 (UTC)

North-East Texas. schyler 02:46, 11 September 2006 (UTC)

Are the leaves similar to grass leaves? It might be some kind of lilyturf - grasslike plants in the lily family. This one looks like it, Liriope muscari.

http://www.magnoliagardensnursery.com/productdescrip/Liriope_Big.html Gary 17:54, 11 September 2006 (UTC)

copyright, publication, volumes, and authors

How and or where do you find the publication date and city of the encyclopedia? Where do you find the author? Where do you find the volume of the encyclopedia that you are using online? Where do you find the copyright dates?

Misplaced Pages:Citing Misplaced Pages Melchoir 01:30, 11 September 2006 (UTC)

September 11

Identifying mission patches

Can anyone identify some blurry space mission patches? there are four here we haven't been able to identify, but we got all the others. They range from all over the place, Canadian Astronaut Service, Shuttle missions, Apollos. One of them looks like they have a house on it, but I haven't been able to find anything. - A.J. 01:17, 11 September 2006 (UTC)

Darned if I know. But I was shocked to discover that we didn't have an article on mission patches—so I started one. If you're an enthusiast, please feel free to flesh it out. TenOfAllTrades(talk) 03:28, 11 September 2006 (UTC)

Don't know any of those four, but the bottom one I can identify as that space insignia. Sometimes called a vector, or a wishbone, it is like an "A" representing the abstract of a rocket. You know what I mean? — (talk) (Desk|Help me improve)

The ship in the movie Virus?

I've been exceedingly curious for apparently no reason as to what this vessel was for. As I remember, it looked real enough in the film. The movie claims that it's some kind of Russian space agency secondary control center but I cant find anything about that.

Appreciate the help

If I remember right they were on a tugboat. Maybe wrong movie. — (talk) (Desk|Help me improve)

Virus (1999 film) says Mac is right, it was a "sea tug".  freshofftheufoΓΛĿЌ  09:03, 11 September 2006 (UTC)

I'm pretty sure they are reffering to the russian ship which the tug boat crew boards with the idea of salvaging for large sums of money. (Little do they know that the ship has been affected by a sentient bolt of lightning form outerspace and that all manner of mechanized zombies await them! No, seriously, that's the movie plot.) I don't remember much about the ship though. -Razma Dreizehn

Microscope Eyes

Sometimes, under the right conditions, my eyes somehow reflect light and let me see microscopic thingies on the surface of my eyes. I can clearly make out hollow cells joined together in rather short groups. It looks like this: http://img242.imageshack.us/img242/7062/untitledzz4.jpg The 'cells' move across my eyes usually from up to down. This phenomenon happens in bright light, I think. I wear persciption glasses, but I think that it has happened without me wearing glasses too. Has this phenomenon ever been reported by other people, or am I the only one? What conditions do I need to have to see this more often?--Codell 03:20, 11 September 2006 (UTC)

Floaters, possibly? Melchoir 03:22, 11 September 2006 (UTC)

Yes, they're probably it. Thanks.--Codell 03:29, 11 September 2006 (UTC)

Nice illustration! — (talk) (Desk|Help me improve)

I get something like that, too. They are always out of focus with me, and I usually get them when I first wake up. I always assumed they were slime on my eyeball. After a few blinks they go away. I can't look directly at them, because moving my eyeball causes them to move. StuRat 05:11, 11 September 2006 (UTC)

because they're on your eyeball. And you know that, but still can't resist the urge to try and look at them, right? Btw, how was that photo in the article made? Did someone stick a camera in their eye? :) Probably not, but it looks pretty much like the real thing. DirkvdM 08:53, 11 September 2006 (UTC)

This is probably one of the most asked questions on the Science desk. It's still cool though, I always kept it a secret when I was a kid because I figured no-one would believe that I was seeing red sperm in my eyes.  freshofftheufoΓΛĿЌ  08:56, 11 September 2006 (UTC)

the famous salt problem

I seek to master the famous salt differential equations problem. how might i TraIN! Jasbutal 07:04, 11 September 2006 (UTC)

If it's so famous, how come neither I nor Misplaced Pages (salt differential equation) have ever heard of it? DirkvdM 08:55, 11 September 2006 (UTC)

Maybe this is it:

A tank is filled with 1000 L of brine, containing 15 kg of dissolved salt. Pure water flows into the tank at a rate of 5 L/min. The solution is kept completely mixed, so the concentration of salt is uniform, and the solution flows out at 5 L/min. How much salt is in the tank after t minutes? after 20 minutes?

The answer to that question is 13.6 kg by the way.  freshofftheufoΓΛĿЌ  09:00, 11 September 2006 (UTC)

It could also be the equation in geophysical fluid dynamics which at least one person has called "Conservation of Salt" - ${\displaystyle \nabla ^{2}S=0}$. Then again, thinking about it, that may just be an extension of the above problem - it's just a statement that the amount of salt in a system is based on the flow in and flow out. Confusing Manifestation 00:55, 12 September 2006 (UTC)

Time to freeze water?

Is there a formula for figuring how long it will take to freeze a given volume of water at a given below-freezing temperature? I couldn't find one with a brief web search, but figured there should be... -Goldom ‽‽‽ ⁂ 07:41, 11 September 2006 (UTC)

For one you'd have to know the starting temperature of the water. And then the contact area and the heat conductivity of the container. And the shape too, but I assume that if there will be any such formula it will assume a shape that has a simple geometric description, such as a cube. DirkvdM 08:59, 11 September 2006 (UTC)

And the pressure would also matter, as well as any impurities and nucleation sites in the water. StuRat 09:33, 11 September 2006 (UTC)

There is a specialised description, the heat equation, but it is probably more complex than what you're looking for. Xcomradex 09:13, 11 September 2006 (UTC)

You'd also need to know the pressure and the starting temperature of the water. I don't believe there is a formula as there is the unexplained (I would be delighted to hear any explanations) problem as to why hot water freezes faster than cold water when the same volumes (and shapes) are put in the same (below freezing) tempreature and the same pressure. — Preceding unsigned comment added by OEYoung (talk • contribs)

How can hot water frezze faster than cold? More energy has to be removed from the hot.--Light current 12:31, 11 September 2006 (UTC)

Visit the Mpemba effect page for some info on this counterintuitive situation. DMacks 12:37, 11 September 2006 (UTC)

Compare this problem with that of 2 capacitors of equal value charged up to different voltages. When they are discharged thruough equal resistances, which one reaches V volts first? Certainly not the one charged higher initially!--Light current 12:41, 11 September 2006 (UTC)

Thanks DMacks - I couldn't remember the name. I didn't believe it myself until I tested it. If you can come up with the reason for it it'd probably win you a nobel prize! — Preceding unsigned comment added by OEYoung (talk • contribs)

Water gives up dissolved gases when heated. Dissolved gases should lower the freezing point of a solution. So if it is previously heated but allowed to cool to the same temp as the cool water, it should freeze faster.Edison 19:05, 11 September 2006 (UTC)

Ayup, that's one of the seven explanations given on the Mpemba effect page. DMacks 21:14, 11 September 2006 (UTC)

Well its not pure water then is it? Its actually a different liqiud and can be expected to behave differently. You must not compare apples and oranges. THeyre different--Light current 00:20, 12 September 2006 (UTC)

Pure water doesn't exist (pure anything doesn't exist). So what we call 'water' is a range of solutions. Only when the impurities become too big an ingredient will we stop calling it water. Any rules on that? DirkvdM 09:06, 12 September 2006 (UTC)

olympic and islam

I "created"an article concerning muslim athletes participating in olympic games.

I am unable to locate the article.

I am understanding that anyone can write an article..

please advise.

• This question would be better placed at the help desk. Anyway, please sign your questions using the signature buttom or 4 tildes (~) so we can easily see who you are and what you edited. - Mgm| 10:20, 11 September 2006 (UTC)
• Anyone can edit an existing article, but too write a new one you need to register an account and log in using the link on the top right of the page. You added this question with your IP address suggesting you're not logged in. - Mgm| 10:22, 11 September 2006 (UTC)

Why did nobody die of a heart attack before 1923?

Whilst perusing the Uni of Manchester website I came acroos the above statement.

Anyone have any idea as to where it originates from and also, if it's true?

--DPM 10:28, 11 September 2006 (UTC)

In the last century, heart attack has been the lay term and legal term for any type of sudden death in an adult attributable to myocardial infarction or any other heart disease. Heart attack entered common language in the first decades of the 20th century. It began to appear on death certificates in the early 20th century. The detailed concept of myocardial infarction in its strict sense (death of heart muscle because of interruption of blood supply) also dates to the early 20th century. The statement does not mean that no one ever died of a myocardial infarction before 1923 but that the cause was not recognized and described with the more familiar term. alteripse 10:55, 11 September 2006 (UTC)

This naturally raises the question of what it was called when somebody grasped their chest, then dropped dead, before 1923. StuRat 14:22, 11 September 2006 (UTC)

Well heart-failure and heart-shock go back to the 19th century, maybe English speakers didn't like to talk about it before then. Apoplexy more usually means a stoke but it sometimes refers to any fit, faint or attack. MeltBanana 14:43, 11 September 2006 (UTC)

Perhaps it has to do with nobody dying of cancer until recent years. — (talk) (Desk|Help me improve)

I doubt it. i would say the success of identifying people with weak hearts, medication and open heart surgury are more likely to be contributing to the increase in cancer. I have no data to back up this thought though. David D. (Talk) 20:50, 11 September 2006 (UTC)

By that, I was trying to imply that it is the diagnosis that began in 1923, not that heart attacks didn't happen. ;) — (talk) (Desk|Help me improve)

This is becoming more of a linguistic question than a science question; maybe the scholars over at the Language Reference Desk can help. --Ginkgo100 20:34, 11 September 2006 (UTC)

Not semantics, this is a pair of definite history of medicine questions. How was this type of death conceptualized and understood a century ago? How much has the rate of death from this cause (regardless of what it was called) changed between the 19th and 20th centuries. The first answer I gave was off the top of my head, but I have a few late 19th and early 20th century medical texts at home and I will see if I can give a slightly more precise answer. alteripse 21:01, 11 September 2006 (UTC)

The question is: Has there been an increase in deaths due to myocardial infarction since 1920 (or whenever)?--Light current 21:08, 11 September 2006 (UTC)

Usually these sorts of questions are easier to deal with if you pick more controversial "illnesses"—i.e. ADHD. Questions like the "heart attack" one are meant to destabilize even things which seem more concrete as well. The ADHD page unconsciously gives a good example of the sort of methodology that makes a historian cringe when it identifies ADHD in Ancient Greece — once you've decided on an arbitrary diagnoses, you can go back in time and read any disease into past writings, even though the conceptual/dianostic category did not exist at the time. --Fastfission 22:23, 11 September 2006 (UTC)

satellites

This is not homework.

Suppose there is a satellite in an orbit of 10r ( r is the radius of the earth) which falls back to earth due to a malfunction. What will be the speed with which it will impact the earth's surface ???????

Its terminal velocity--Light current 12:25, 11 September 2006 (UTC)

Thats not necesarily true. It could reach much higher speeds in space, and then not accelerate back down to its terminal velocity in the atmosphere. If it did hit at its terminal velocity, it would be a bit of a coincidence. Philc _TC 13:58, 11 September 2006 (UTC)

I disagree. With an artificial satellite, the size is small enough and the Earth's atmosphere is thick enough that it would be sure to decelerate back down to it's terminal velocity, unless it burns up in the atmosphere first. StuRat 14:19, 11 September 2006 (UTC)

The smaller an object is the less it will be slowed down by drag. Most physicists would use the word accelerate in this situation to mean slow down - (the magnitude of) acceleration can be positive or negative. - Not Philc.
P.S. its terminal velocity.

Thank you anonymous person. StuRat, Decellerate is a non scientific word coined by the US scientific community to remove some ambiguity, but has since lead to common missuse of the word acelerate, it actually means a change in velocity, which means a change in direction and/or a change in speed. The shuttle is a view of the sort of shape you need to control your decent, incredibly wide in proportion to height and weight, sattelites and meteorites, etc, are not of good proportion for slowing down, and if they are large enough to impact before they burn up, would almost always impact at a much higher speed than terminal velocity. Philc _TC 15:26, 11 September 2006 (UTC)

"Decelerate" seems like a perfectly good word to me...or shall we also have the temperature "heat back down" to freezing, and the budget "increase back down" to zero ? If you want to use the phrase "negative acceleration", that's fine too, although a bit formal for common usage, for my taste. StuRat 16:15, 11 September 2006 (UTC)

Thats my point exactly it is incorrect to assume acceleration is an increase it is not it is a change, if their is a change in temperature it does not imply a rise, and if there is acceleration it does not imply a rise in speed or even any change in speed, but a change in velocity, wether it be a increase or decrease in speed or a change in direction. Maybe you should consuclt the article beofre speaking again. Philc _TC 16:34, 11 September 2006 (UTC)

Just as a "change in temperature" does not imply a temp increase, a "change in velocity" does not imply an increase. However, if something is heated, that means an increase in temp, and when it is cooled, that means a decrease in temp, just as something which is accelerated means an increase in velocity and if something is decelerated, that means a decrease in velocity. Now, you could refer to zero acceleration or zero deceleration to mean the object is not accelerating at all, and you could even refer to negative acceleration, or even negative deceleration, if you must. But to describe an object as "accelerating" when it is slowing down is horrid, and bound to confuse everyone. StuRat 12:28, 12 September 2006 (UTC)

I think one problem with the term "deceleration" in physics is that in one intertial reference frame, an object is slowing down - whilst in another intertial frame, the same object is actually increasing in speed. Both reference frames are equally valid viewpoints in which the laws of physics are identical - yet one viewer is seeing the object slow down - the other speed up. The force applied in both cases is identical (it's just the same object after all) Acceleration need not refer to a change in speed as well - a planet orbiting the Sun in a circular orbit at constant speed is continuously accelerating (towards the Sun). In useage within the general public - viewing from different reference frames are not usually important as we usually have the Earth as our reference frame - but imagine flying in a plane above heavy cloud - you don't have any perception of movement other than the rumble of the engines and occasional turbulence. Another one about reference frames is in, say a car crash. Ask someone about what happens, and they'll say that loose things in the car were "flung" forwards i.e. accelerating. Measure what's actually happening from outside the car - and they're slowing down. So my point is that acceleration is just the rate of change of velocity - and it has a direction (which you could regard as being in the + or - direction for linear changes in speed). But it's odd to talk about an object simultenously decelerating and accelerating as a reaction to the same force - when they're just being viewed by 2 different observers.Richard B 21:19, 12 September 2006 (UTC)

Ok, if dealing with an acceleration in a constantly changing direction, I take your point. However, acceleration may also refer to a scalar, where the direction doesn't change. In such a case the term "deceleration" for negative acceleration is perfectly clear. StuRat 22:37, 12 September 2006 (UTC)

That's not quite correct. Acceleration does not vary between reference frames - only uniform motion does. In your car crash example, the loose objects would not accelerate (ignoring gravity and air resisitance). The passengers would decelerate (disambiguation) - they would feel the force of the seatbelts slowing them down. From their reference point they will decelerate, the objects will continue in uniform motion. The same will apply to the observers standing outside the car - they will see the passengers decelerate and the loose objects continue.
Your arguements about the relative motions are perfectly acceptable for special relativity, but when dealing with changes in velocity one must use general relativity. The fundamental principle of relativity does not apply to accelerating frames.

I have no idea why you're so bent out of shape over the use of the term decelerate. I have a B.Sc. in physics and don't recall ever being told it was a naughty word. In any case, you're getting off the topic. It boils down to whether there's enough time for the object to decelerate, negatively accelerate or just plain slow down to terminal velocity before it burns up or hits the ground. Drag and barometric formula seem to have some pertinent equations, if somebody has the inclination to work on it (hint, hint). Clarityfiend 19:51, 11 September 2006 (UTC)

Decelerate is a scientifically incorrect term coined and regularly used by the american scientific community. It, like many other words, despite being officially useless, is commonly used, amongst those in that community. Its not a taboo word, it just inst a proper word, its fine to use it because everyone knows what it means, but my original point was, that you can accelerate so that your speed drops. Which is perfectly true, and I'm sure if you do have a BSc that you will know this. Philc _TC 20:26, 11 September 2006 (UTC)

Sorry, but that's completely wrong. Accelerate does mean to increase speed, and always has. See the word origin here: . StuRat 06:35, 12 September 2006 (UTC)

Speaking as a physicist, (in scientific use) accelerate does not always mean to increase speed. It means change in velocity - that's increase in speed or decrease in speed or change in direction of motion (or any combination). While to say decelerate is not incorrect, to assume accelerate means speed up is wrong (as is to correct peoples usage of the word).

Ur such an ass have you not tagged onto the fact were talking about physics terminology, not english words, and in physics, accelerate = changin velocity. FINAL!,(you cant have a rise in velocity, as you can change velocity while travelling at a constant speed, so is this a rise or a fall?). maybe this site would be of more help, it is an idiots guide to physics. i linked to the section acceleration. For gods sake people. Get over yourselves, decelerate is used in common english, in which it is a word, but in science, it is basically scientific slang. Mate, get over yourself, its ok to be wrong. Philc _TC 17:49, 12 September 2006 (UTC)

Philc, you are resorting to personal attacks and name-calling, which are completely inappropriate in Misplaced Pages, and not permitted. Please behave in a civil manner. StuRat 22:18, 12 September 2006 (UTC)

Interesting. The entire American scientific community is using an incorrect term? Sez who? (And yes, I know quite well that acceleration is a vector quantity yadda yadda yadda.) Clarityfiend 22:11, 11 September 2006 (UTC)

The smaller an object is the less it will be slowed down by drag ... umm ... surely the opposite is true ? For an object travelling much faster than terminal velocity, magnitude of acceleration is approximately proportional to drag divided by mass (assuming drag >> weight); drag is proportional to cross-sectional area; mass is proportional to volume; so magnitude of acceleration is proportional to cross-sectional area divided by volume, and this ratio goes up as size of object decreases (assuming we keep shape and density fixed). Gandalf61 15:58, 11 September 2006 (UTC)

Agreed, I picture small grains of "sand" landing at thousands of miles per hour, and killing anyone they hit, if that was actually the case. Meanwhile, the meteor that killed the dinos would have just settled down like a feather. :-) StuRat 16:06, 11 September 2006 (UTC)

Hmm ou did take it a bit out of context, it can be assumed that any unmentioned variables were held constant, i.e. weight. Philc _TC 16:29, 11 September 2006 (UTC)

Assuming that objects of different volumes have a constant mass is not reasonable. You should assume a constant density, instead. StuRat 06:18, 12 September 2006 (UTC)

Deceleration

Google gives 1.2M hits for decelerate. What does that prove?--Light current 21:10, 11 September 2006 (UTC)

Google has 1.2 million hits for blof, what does this prove? Philc _TC 17:53, 12 September 2006 (UTC)

THis thread seems to have veered off topic. THe initial answer I gave was more than sufficient. I suggest a new hdg if you all want to discuss the correctness of the term 'deceleration'. --Light current 21:17, 11 September 2006 (UTC)

Depends. How does the malfunction alter its intial velocity. Does the malfunction cause it to leap into an elliptic orbit with astoundingly good impact parameters to allow a simple atmospheric reentry. Or does the malfuction cause the satellite to explode into <1 cm debric that rains down over an entire hemisphere? Does the malfunction cause the satellite to suddenly accelerate towards the planet at nearly the speed of light?

If we posit that the malfunction causes no initial acceleration of the satellite, then the dynamics are one of orbital decay which strongly depends on solar activity and sunspots. Especially at an altitude ot 64 Mm (earth radius times 10). At such an altitude, the density is very low (q.v. Image:Atmosphere model.png), we may read off < 1 microgram per cubic meter (achieved at 0.15 Mm) and (wildly) extrapolate (-9 orders of magnitute per 0.15 Mm) ~10 gram per cubic meter (with a huge irrelevant error, because...). This is lower bounded by the solar atmosphere. The solar wind is ~1 Tg/s of material moving at 450 km/s. At the orbital radius of the earth (150 Gm), the density of the material is ~5 proton masses per cubic centimeter. However, the satellite's original orbit is inside the Earth's magnetosphere, so the density is assumed to be a bit lower, by cyclic. Kepler's third law tells us that the satellite at 10r will orbit once every (384 Mm / 64 Mm) * 27 days ~= 1.8 days (Q.v. the Moon's orbital radius and period). The rate of decay will be negligible (due to the very low atmospheric density).

Satellite Orbital Decay suggests that the densities may be higher than expected from the above considerations (due to temperature fluctuations and mass fraction considerations not present in the above). This paper describes in some detail the effect of solar activity on the drag force, even for low-orbit sattelites like the Hubble Space Telescope and therefore should be a good starting point on the problem you've posed. -- Fuzzyeric 22:31, 11 September 2006 (UTC)

Hmmm...now that I think about it, it seems to me that there's a simpler way of looking at it. Just imagine a rocket leaving the Earth. It has to be going just over 11 km/s (about 36,000 km/hr) to get away. Reverse it and a satellite (ignoring for the moment whatever orbital velocity it has) would return at about that speed. Now, I remember from an earlier question posed here, that astronauts report that atmospheric drag is noticeable at about 120 km up. So, it seems unlikely that an object travelling at that speed would be able to decelerate to terminal velocity in that short a distance and time (it would probably come in at an angle, but still). My conclusion is that one of three things would happen: (1) it could come in at too shallow an angle and bounce off the atmosphere (as discussed in the movies Apollo 13 and Space Cowboys), (2) burn up or (3} hit at considerably in excess of terminal velocity. Clarityfiend 17:15, 12 September 2006 (UTC)

I don't think there's any easy way to calculate the answer. You'd need to know whether the malfunction caused its thrusters to activate. If it's a homework question, then it's probably after the difference in the potentials between r = 10R, and r = R, starting at v = 0, neglecting air resistance. Richard B 21:24, 12 September 2006 (UTC)

Sorry to bring up a topic that seems to have run its course, but I can't help but find the whole "accelerate/decelerate" debate quite amusing. I may not have a BSc, but I do have an LLB/BCL, so I'm familiar with the way members of certain disciplines tend to "borrow" words from the English language, mangle and distort their original English language definition, and then claim that they're using the word correctly, and you, a simple English language speaker are wrong in using its original, true definition. Let's be clear, science, like law, uses the English language, NOT the other way around. An example I always bring up is that according to "legalese", the English word "person" has been extended to include non-human entities such as corporations. According to "legalese", a corporation is a person! We actually had a rather funny discussion about the whole thing in law school. The professor stated, with a straight face, "If the law defines you as a carrot, you're a carrot!" The same thing seems to be going on here. I would never be so arrogant as to insist that a corporation, in reality, is an actual person. Sure, it may be the way we've twisted and contorted the English language to suit our needs, and that's ok. But all due deference must be given to the actual, real life, language from which we've borrowed, mangled and distorted certain words to suit our needs. I will never be a carrot, no matter what the law says. Perhaps the law may decide to consider me a carrot, but the English language does not. Likewise, in the English language, a person is a human being and a human being only. The "law" may consider a corporation to be a person, but the English language does not. Similarly then, to accelerate is to increase velocity and to increase it only. Sure, the scientific community may decide to define "acceleration" as whatever the hell it wants, and that's ok, if it contributes to a better understanding of science. But again, science uses English, not the other way around. Due deference must be given to the original source of the word. If you choose to mangle it, that's ok, but never be so arrogant as to forget its original source. To me, the only acceptable approach would be to say: "true, to accelerate indeed does mean to increase in velocity and to increase only, however, for scientific purposes the scientific community has chosen to define it differently". Loomis 22:06, 12 September 2006 (UTC)

I used the word accelerate in its physics meaning, in physics context, and was told I was wrong. I was not, and that basically the jist of it, languages have words, science has words, but accelerate in a context of physics is defined by physicists, in other contexts you can claim it means whatever you want, but the simple fact is, I was told I was wrong, when I was right. Philc _TC 22:19, 12 September 2006 (UTC)

I must take issue with you here, Phil. You've proven to me in the past that you're a good guy, so I'm not exactly enjoying contradicting you. The fact is, though, that you didn't merely state that you were using a scientific definition of the word that differs from its true English language meaning. Rather, you did the opposite. You accused the "US scientific community" of "coining" a "non-scientific word", and further, you argued that it has "since lead to common misuse of the word accelerate". Phil. C'mon. That's ridiculous. You make it seem like English speakers should thank scientists for inventing the word "accelerate", and then humbly submit to their understanding of the word. The word "accelerate" is an English word. So is the word "decelerate". It's the scientists who are deliberately misusing the word, not the other way around. But as I said, there's nothing wrong with that, as long as the original source of the word is acknowledged. Loomis 22:44, 12 September 2006 (UTC)

Tfl Oyster system

Could you please tell me who supplied the equipment to Tfl for their Oyster cards system?

Sure, but next time why don't you try searching using the search box on the left - it's quicker! See Oyster card for the gory details. --Robert Merkel 12:59, 11 September 2006 (UTC)

.flv

Hi is there a free software taht transforms .flv files to otehr formats like mpeg4 or avi or 3gp etc somethign liek that? Thanks!

Yes, there is lots of software that works with FLV. Try searching with the search box on the left of your screen next time, it's quicker! --Robert Merkel 13:01, 11 September 2006 (UTC)

Solution of vessels

I already asked this question in great detail in August but I got no responses and then the question just got deleted off the wikipedia. So I'll try again but I am reluctant to write as copiously a≈s before. Also I was told there was nothing ever on about "solution of vessels" so maybe I'm not using the system correctly.

Basically, I was requesting information about the relative solubility of vessels (eg.wood, plastic, glass etc) containing (to make it simple) water (tho that is obviously not a constant as varies according to acidity, temperature etc.)

My query arose out of comments of a fastidious niece that she would not drink anything out of plastic bottles, because the "water got contaminated", but glass was OK. A retired scientist said that all this is a waste of time as the rates of solution are so miniscule as to be insignificant, "like glass flowing down a window pane!".

Anyway, I would just like to know. Does anyone have comparable statistics? 87.74.46.191 13:35, 11 September 2006 (UTC)Francis D. O'Reilly

Although we never came up with any stats, this issue was discussed extensively, and was archived after 7 days (not deleted), here:. StuRat 13:51, 11 September 2006 (UTC)

Last I checked glass does not dissolve into water. — (talk) (Desk|Help me improve)

Agreed; but the rest do, with plastic being the worst, then metal, then wood. StuRat 16:00, 11

September 2006 (UTC)

Glass also does not flow downward in window panes. That is a myth resulting from blobby old blown glas being mounted in windows. There are ancient Roman bottles which have not shown any tendency to melt into a puddle like Silly Putty, but people assume 300 year old glass in a church window is melting.Edison 19:10, 11 September 2006 (UTC)

One way to come at this problem is to investiage hoaxes related to water containers leaching materials into their contents. This Snopes article describes a hoax claiming that the reuse of plastic water bottles can leach plasticizers into their contents. This is false. This article debunks the claim that microwaving in plastic containers will release carcinogens into food. -- 205.162.232.254 21:27, 11 September 2006 (UTC)

Those Snopes articles do say "FALSE" at the top, but that really isn't what they say in the body. On microwaving, for example, they said something closer to "when using a microwave safe rated plastic according to the manufacturer instructions, there is currently no evidence that dangerous levels of toxic chemicals are released into the food". This leaves open the possibilities that there are toxic chemicals, in dangerous levels, but this has not yet been established, or that using improper plastics or microwaving improperly will generate toxic levels of chemicals in the food.

Moreover, they seem to approach all questions with the attitude that "let's assume everything is healthy, unless we have evidence to the contrary", while many people, myself included, would say "let's assume everything (especially relatively new things) is dangerous unless we have specific evidence to the contrary". Obviously eating or drinking from plastic isn't immediately 100% fatal to everyone who does so, but if it caused a 10% increase in cancer, after 20 years, this wouldn't be easy to isolate as having been caused by plastic containers. So, I prefer to play it safe. If I can taste the plastic in my food or drinks, I don't eat it, for both safety reasons and because it's quite unpleasant. StuRat 06:11, 12 September 2006 (UTC)

Which leaves the question how much harm it could do. Some people don't rinse after washing the dishes. How much washing up liquid do they consume in a lifetime and how much harm can that do? Of course, all this is probably negligible compared to the exhaust fumes a city dweller inhales. And there are many other things that will have a negative effect (do you ever drink alcohol?) and the negativest effect might verry well be worrying too much about it all. I'm a happy smoker, for example. But I also take the stairs in stead of the lift, so that should compensate. :) DirkvdM 09:26, 12 September 2006 (UTC)

Yes, that will assure that you will be nice and thin while you're hacking up bloody pieces of lung. :-) StuRat 12:18, 12 September 2006 (UTC)

BTW, it's "instead", not "in stead". StuRat 12:18, 12 September 2006 (UTC)

StuRat, I think the Snopes article is assuming that without evidence of harm there is little good reason to assume it. But in any case the difference you are talking about is the difference between something like probabilistic risk assessment (popular in the US) and the precautionary principle (popular in Europe) approaches to hazards. --Fastfission 12:09, 12 September 2006 (UTC)

As a neurotic, I worry about far too many things. Some would even call me a "negativest". :--) Loomis 21:18, 12 September 2006 (UTC)

Need full citation for Gibbard and Kolfschoten chapter (glaciation timeline ref)

Hi,

I wondered if you could send me the full citation for the reference you use for the glaciation timeline. I was able to download the book chapter, but I have no idea where the chapter came from. Can you send me the title of the book, the year published, publisher, and location of publisher?

Thanks,

Emily Lemmon

Here is a the web site:

It contains this relevant text:

Now published - A Geologic Time Scale 2004 Felix Gradstein, Jim Ogg & Alan Smith. **The Quaternary chapter by P.Gibbard & Th. van Kolfschoten, which includes a CORRECTED version of the correlation chart, including the term QUATERNARY. pdf

StuRat 14:13, 11 September 2006 (UTC)

Portal Paradoxes

Any eds who know anything about this topic are welcome to look at this recently created article. As a definite non-scientist, I can't begin to tell if it's nonsense or original research (or not). --Dweller 14:31, 11 September 2006 (UTC)

Speaking as a scientist, a definate non-scientist you shouldn't have a problem with this definately non-scientific article.
For a more scientific approach to something similar the wormholes article should answer the questions posed in title article or else demonstrate that, even in principle, the situations presented are flawed.

Portal Paradoxes, in my opinion, should definitely be deleted. It is both an essay and original research. I've nominated it for deletion. --Allen 15:08, 11 September 2006 (UTC)

I agree. Rather a non-encyclopedic tone as well. — (talk) (Desk|Help me improve)

It appears to be complete pseudo science made up by someone who doesnt actually know anything about the subject. Philc _TC 15:20, 11 September 2006 (UTC)

It appears to be referring to some type of portal from a video game, not a science topic at all. Unfortunately, they don't identify the game. StuRat 15:52, 11 September 2006 (UTC)

erm... they did. I came across the article when patrolling new articles. I deleted the advert. Twice. But left the article, feeling out of my depth on deciding if it was or wasn't guff. Anyway, thanks to those in the know for confirming it is, indeed, a load of tosh. --Dweller 16:26, 11 September 2006 (UTC)

Well, as I said, it is scientifically worthless, but, if it's accurate info for a particular video game, it could still be "encyclopedic", provided it identifies the game. After all, we have many articles on other games, like countless articles on Pokemon characters. StuRat 16:53, 11 September 2006 (UTC)

It doesn't even define what a "portal" is. Definitely not physics. Clarityfiend 18:59, 11 September 2006 (UTC)

In case you're still scratching your head what the article is about, it's about Portal (computer game). It's still perfectly deletable, though -- Ferkelparade π 21:18, 11 September 2006 (UTC)

Well somebody better merge some of it in fast than! I can't do it now because I should be doing work that is not Wikipediaing. — (talk) (Desk|Help me improve)

Isnt all this stuff covered in Wormhole? Oh yeah, just seen ref to that ^. THis page is pure fantasy nad of course should be deleted. But why are we discussing deletion here may I ask?--Light current 00:47, 12 September 2006 (UTC)

700ml liquor + sertraline

A friend of mine is on sertraline for bipolar disorder, and has an intimate relationship with rum. I think the sertraline is taken once a day and then he drinks a 700ml bottle of rum (37.5% alcohol) on a single day. Every week. How big of a risk is there that he will become an alcoholic and/or bust his liver due to combined pill/liquor use? Jack Daw 15:47, 11 September 2006 (UTC)

I don't know about any drug interaction, but that much alcohol alone can certainly cause health problems. StuRat 15:54, 11 September 2006 (UTC)

Drinking spirits is the worst thing for the liver, I saw a documentary once and the doctor doing the liver transplant said that binge drinking spirits once a week was enough to do the damage and worse than say the equivalent alcohol dosage in beer/larger. Dont know anything about the drug.

I'll echo what's been said above. Drinking a fifth of liquor every day is going to hurt your liver whether or not it's in combination with other drugs. TenOfAllTrades(talk) 17:41, 11 September 2006 (UTC)

As for the alcoholism thing - someone who drinks a bottle of rum a day probably is an alcoholic already (though, of course, there's more to alcoholism than just drinking). Like any drug, sertraline takes its toll. Of course, if you're self-medicating that heavily, the antidepressant probably isn't working for you. Guettarda 17:49, 11 September 2006 (UTC)

He's been doing this stuff for maybe two years now, then stopped for two months (of course that was only what he told me), but telling from the alcoholism article I don't think there's any alcoholism yet. Jack Daw 20:30, 11 September 2006 (UTC)

Come off it! Anyone whose drinking a bottle of sprits a day is obviously an alcoholic! You should force your friend to see a doctor (or if you cannot afford that then at least AA for example) and get him treated to stop the drinking. With that amount of drinking, and the other drug, then its obvious that if he dosnt stop drinking he's going to be dead soon. Harsh words, but they need to be said to save your friend. 81.104.12.61 22:14, 12 September 2006 (UTC)

From Sertraline#Precautions

• Liver impairment can affect the elimination of this drug from the body. If someone with liver impairment is treated with sertraline, lower or less frequent dosage should be used.
• Patients should limit their alcohol intake while on sertraline (or any antidepressant). Because the liver is doubly taxed with processing both substances (in addition to any other drugs the patient may be taking), alcohol remains in the bloodstream longer, so the effects of alcohol may be more strongly and quickly felt by people taking sertraline or other antidepressants.

which meshes pretty well with what I (vaguely) remembered. Guettarda 17:58, 11 September 2006 (UTC)

"A 'Friend of mine' has a problem?"Edison 19:12, 11 September 2006 (UTC)

Yes? Unless you have some kind of evidence that it's me rather than said friend who has these problems, please refrain from that kind of comments. It would be pretty useless to denote my friend by any other "name" than 'my friend'. Jack Daw 20:30, 11 September 2006 (UTC)

I thought mixing alcohol and mood altering drugs could have have very undesirable effects.--Light current 06:10, 12 September 2006 (UTC)

amyloid beta

Do mice naturally make amyloid beta (specifically in the brain)?

Yes, mice make amyloid beta. It is not identical to human amyloid beta, but close enough that researchers use mice to study Alzheimer's disease. --Ed (Edgar181) 19:50, 11 September 2006 (UTC)

Highly enriched Uranium

I searched wiki but could not find the relevant information. My specific questions are — who can manufacture (specifically, can Pakistan do it on its own?) 99.9% enriched U-235 and what are its implications. What will be the critical mass for Atomic bomb with this purity. {enrichment for little boy was just about 80%.}

Background for this question is that two Muslim terrorists were arrested on suspicion in Bareilly, India about a few years ago. Police found a white powder with them. They initially thought it to be a Drug. But, when they sent it to the Lab, they were shocked at the results, as it was 99.9%pure enriched U-235. Nuclear Submarines just use 90% EU. Remeber that This news was highly censored in India, so you wont find much about it in the archives. But it was once the front page news in The Times of India.nids(♂) 21:30, 11 September 2006 (UTC)

Well the obvious answer is that any one with the right plant and raw materials can do it. As you need enriched uranium for nuclear power stations, I would think most countries who have these, also have the enrichment facilites. THeres one just down the road from me! Iwould think tho that the stuff must have been made in a proper plant rather than in someone's shed. I dont know what compound of uranium is a white powder, but Im sure someone will tell us--Light current 21:37, 11 September 2006 (UTC)

You cant enrich to 99.9% in a shed. The One used in Nuclear power plants is enriched just about from 3% to 40%. Never more. 85% or more enriched EU is always called Weapons Grade. Most submarines just use about 50%. 90%(in special cases).nids(♂) 21:42, 11 September 2006 (UTC)

Im not aware of any specific problems in making more highly enriched uranium above the 50% you quote for sub use. Surely, you just leave it in the 'enricher' for longer?--Light current 21:52, 11 September 2006 (UTC)

it is not as simple as you think. Perhaps you would like to go through Enriched uranium. remeber that the critical mass reduces with enrichment and it is dangerous to enrich it beyond certain levels.nids(♂) 22:00, 11 September 2006 (UTC)

From that page: The critical mass for 85 % of highly enriched uranium is about 50 kilograms. Sounds like quite a lot to me!--Light current 22:05, 11 September 2006 (UTC)

Its the amount with 85% enrichment. Remember that Uranium is extremely dense metal. So the volume of 50Kg. is just about a litre and a half, (i.e. with 85%). Efficiency of critical reaction increases with enrichment.nids(♂) 22:16, 11 September 2006 (UTC)

Yeah thats the metal. Enrichment is done in gaseous form, is it not?--Light current 23:04, 11 September 2006 (UTC)

(edit conflict due to fire drill) the story sounds like bollocks to me, like most stories that invoke a grand conspiracy. For starters, uranium is a silvery metal which gains a black oxide coating, not a white powder, and compounds of uranium, such as uranyl nitrate, which aren't used in fission, are yellow. and the methods for isotopic refinement of uranium are complex, and require difficult to obtain equipment, and highly toxic materials. not beyond a state, but look at how much trouble iran is having. Xcomradex 21:55, 11 September 2006 (UTC)

I am sorry i cant quote much about the news as i told you that it was immediately censored. Nothing came again on TV or any news channel about it and they never published a disclaimer either. I doubt it to be completely wrong as it was the front page headline (atleast for a day).nids(♂) 22:02, 11 September 2006 (UTC)

I request you to leave out the background for this question as i cant defend it. Please answer the specific questions that i posted. Can pakistan do it on its own????nids(♂) 22:04, 11 September 2006 (UTC)

How are we supposed to know for certain? We can only make educated guesses -- as could you.--Light current 22:07, 11 September 2006 (UTC)

99.99% would be remarkably high enrichment; there wouldn't be many countries that could get it that high, if any can at all (I doubt it). After some point, you are really wasting resources to get that extra .01% enrichment—there are better, and easier ways to improve efficiency if you are resource conscious. Judging from that description it doesn't sound legitimate to me — the powder sounds wrong, and enrichment level sounds wrong.

Back to the original question—many types of reactors require at most 3-4% enriched uranium. Some don't require enriched uranium at all (i.e. a heavy water reactor like a CANDU). Reactors which require very highly enriched uranium are usually quite small — research reactors and submarine reactors, for example. I don't know how many places can enrich to 90%, but any enrichment facilities which can go up to that amount are usually under heavy IAEA safeguards, unless the nation in question is not a signatory of the NPT (like Pakistan and India).

Pakistan has a number of unsafeguarded uranium enrichment facilities, all using gas centrifuge technology, and their P-2 centrifuges are recognized as relatively advanced. The country certainly has the ability to enrich uranium to bomb-grade level—its tested nuclear weapons were uranium-core, if I recall. --Fastfission 22:18, 11 September 2006 (UTC)

I have a background knowledge about this subject and i know that it is illegimitate to waste resources after a certain point. But its benefit (for terrorists) are that the critical volume required could be as low as 80 ml (by my estimates). Pakistan for sure can do it to 90%, but i doubted about the figure i gave you in the beginning. With these outdated P-2 Techniques, i dont think that they can even go beyond 50%.nids(♂) 22:26, 11 September 2006 (UTC)

Yes, Pakistan can and did enrich uranium to bomb-grade. The other countries with known uranium enrichment facilities include the big 5 (USA, UK, France, Russia, China), India, and presumably Israel. Brazil has recently opened a centrifuge enrichment plant for making reactor fuel; however, a plant for making reactor fuel could probably be used to make HEU with some reconfiguration (Brazil's centrifuges are reportedly very advanced, as good as European and American ones). As well, Germany, Japan, and the Netherlands have centrifuge enrichment plants, and could also start turning out HEU if they really wanted to.

For completeness, there are a number of other countries who have developed enrichment technology such that they could make nuclear weapons, but haven't done so or have stopped doing so. To take the best known example, South Africa built an enrichment plant, and half a dozen nuclear weapons, but abandoned the program and dismantled both the enrichment system and the weapons when the apartheid state ended. To take another, Australia built a pilot-scale centrifuge enrichment plant, but did not progress beyond that stage by choice.

But could terrorists do it without the support of a state backer? Pretty unlikely. An enrichment plant is a very considerable industrial operation; the parts have to be made with very, very high precision or the centrifuges will simply disintegrate. Gas diffusion enrichment would require so much electricity that it would be obvious to all and sundry that there was something going on in the building concerned.

Nids' comment of a risk of a criticality accident when trying to reach HEU is interesting. I would have thought myself that it wouldn't pose that much of a problem in the centrifuges or the piping, as they are both very long and skinny. I could see that subsidiary parts of the plant might need to be carefully designed though. --Robert Merkel 23:10, 11 September 2006 (UTC)

I am skeptical of a 99.99% enrichment. 85% would be just fine, 95% is weapons grade isn't it? — (talk) (Desk|Help me improve)

Why do you say 85% is just fine? Did you have a particular purpose in mind?--Light current 23:44, 11 September 2006 (UTC)

How many purposes do Pakistani terrorists have for weapons grade uranium? Two? — (talk) (Desk|Help me improve)

(FYI, Mac Davis, you appear to have accidentally increased the purity by an order of magnitude - the question has three 9s but you wrote four 9s in several places.) —AySz88\^-^ 04:07, 12 September 2006 (UTC)

But 85% isnt weapons grade is it? So how is it 'just fine' ? Dya wanna make a real A bomb or just a dirty damp squib?--Light current 00:53, 12 September 2006 (UTC)

I think when you are talking about enrichment levels below 93.5% you are essentially asking about the difference between a nuclear weapon and a dirty bomb (assuming you do not have other very high-level technologies—I imagine that there are ways to increase the efficiency of a lesser enriched bomb if you could do things like use very reflective tampers and fusion boosting). --Fastfission 00:31, 12 September 2006 (UTC)

Well, that contradicts what I've read. A gun-type bomb made of 80% HEU would, apparently, work just fine, albeit with half the yield of the same amount of 90% HEU. See this article on the South African nuclear bomb. --Robert Merkel

I was going off of this article by a number of ex-nuclear weapons designers, though with them again one has to wonder what they consider the line to be between a "successful" nuke and an "unsuccessful" one (if you are just trying to make a relatively large explosion and a big mess, even a fizzle can be worthwhile). 80% is not technically weapons grade — I don't know what the predicted yield would be, but my guess it that we're talking about five kilotons or two at most, depending on the assembly mechanism. Very inefficient for such a large device but again it all depends on what you are looking for. It is hard to find values on the low-end of nuclear weapons work (Carson Mark has written a number of articles about low-grade nukes) in part because that's the sort of information they consider to be the most valuable to terrorists today (the irony is the big, complicated nuclear secrets of yesteryear are totally useless to terrorists, while the simple things, like "can you use research reactor plutonium in a nuke?", suddenly become very relevant). --Fastfission 12:02, 12 September 2006 (UTC)

enrichment used for little boy was just 80%. By the way, what will be the critical mass for 99.9% EU in your view.nids(♂) 12:15, 12 September 2006 (UTC)

Do we also accept that Pakistan can enrich U-235 to 99.9%.nids(♂) 12:23, 12 September 2006 (UTC)

So it turns out Mac may have been right all along. How the hell did he know that? --Light current 10:22, 12 September 2006 (UTC)

The Bin Laden terrorists supposedly laughed at José Padilla (alleged terrorist) when he proposed to centrifuge weapons grade uranium by swinging it in a bucket which he would hold while he spun around. Superman might have better luck, because he could turn coal into diamonds by squeezing it in his hand. Edison 17:15, 12 September 2006 (UTC)

You are taking the subject too lightly. Are you forgetting that all the terrorists have Pakistani support. Anything that Pakistan can do, is what that Al-Qaeda will have access to. I dont think it will be hard for a suicide attacker to diffuse a bomb from 99.9% Enriched Uranium. They will just need about 100ml volume of U-235.nids(♂) 20:30, 12 September 2006 (UTC)

All terrorists have the support of the Pakistani government? is that what you are saying?--Light current 22:26, 12 September 2006 (UTC)

Yes. Do you doubt it. Even after the reports that Osama is in Karachi in an ISI hideout.nids(♂) 22:59, 12 September 2006 (UTC)

Nuclear attack wouldnt have been a worrying factor had the terrorists not had any support from a government.nids(♂) 23:04, 12 September 2006 (UTC)

Does Dubya know about this? If so why aint he attacking Pakistan?--Light current 23:07, 12 September 2006 (UTC)

Yes Dubya knows it. The details for the answer why he isnt attacking Pakistan are for the Humanities desk. But i think that Pakistan is now a nuclear power, so this isnt possible.nids(♂) 23:17, 12 September 2006 (UTC)

So you are not actually asking a question here, but are making some sort of political statement as you seem to know all the answers anyway and just want conformation of your beliefs. Is that right?--Light current 23:35, 12 September 2006 (UTC)

Leave these questions. I was interested in knowing the critical mass for the HEU of 99.9%, and whether the pakistan has openly accepted that it has facilities to enrich U to 99.9%.nids(♂) 23:49, 12 September 2006 (UTC)

I was precise with my initial post. I had to reply to some of your posts as i knew, perhaps, more than you.nids(♂) 23:51, 12 September 2006 (UTC)

Found this on Urenco site:

Physical Characteristics of Uranium Hexafluoride As it can see from the phase diagram In figure 10, UF6 is characterised by an unusually high vapour pressure for a solid, e.g., 24 mbar at 0 °C, 107 mbar at 20 °C and approximately 1 bar at 56 °C. At this temperature UF6 is a white crystalline solid. The melting point of UF6 is 64 °C, with a vapour pressure of approximately 1.5 bar. The density of solid UF6 at room temperature is around 5 g/cm3. There is a large change in density to 3.7 g/cm3 when UF6 turns from the solid into the liquid state (diagram 11). The physical data of UF6 are given in the following table:

• Sublimations point at 1013.5 mbar 56.4 °C
• Triple point at 1516.5 mbar 64.02 °C
• Density (solid) at 20.7 °C 5.09 g/cm3
• (liquid) at 64.02 °C 3.668 g/cm3
• (liquid) at 148.9 °C 3.043 g/cm3
• Heat of sublimation at 64.02 °C 48 kJ/mol
• Melting heat at 64.02 °C 19 kJ/mol
• Vaporising heat at 64.02 °C 29 kJ/mol
• Reaction heat with water at 25 °C 211 kJ/mol
• Critical pressure 45.6 bar
• Critical temperature 230.2 °C
• Vapor pressure at 20 °C 106.7 mbar
• Molecular weight 352.07 kg/kmol

My bolding. Does this data fit with your story? --Light current 00:35, 13 September 2006 (UTC)

All that i am interested in knowing is that

1. What will be the critical mass for an atomic bomb with 99.9% enrichment.
2. can pakistan do it on its own.nids(♂) 00:57, 13 September 2006 (UTC)

Critical mass of U235

moved to talk:critical mass

Instantaneous Speed

Quite simpley, what is it. If one had to define it in the most explicit terms possible, how would one do so?

It the rate of change of position with respect to time.--Light current 22:00, 11 September 2006 (UTC)

Another answer is that it's the speed something is going at a given moment, as opposed to its average speed over time. --Allen 22:06, 11 September 2006 (UTC)

I'd say the best one can do, physically speaking, is to compare the position of an object at two times that are very close together. Its speed is then the distance traveled, divided by the time passed. In order to be truly instantaneous, mathematically one would like to pass to the limit, but in the real world one doesn't have that luxury. Melchoir 22:17, 11 September 2006 (UTC)

Well... "Instantaneous velocity" is defined by taking the limit. Q.v. formal description of velocity. It is the rate of change of the displacement, where the test time during which the displacement is allowed to occur is reduced. This process (in a macroscopic experiment) will asymptotically approach some value as the test time is allowed to go towards zero. Extrapolated to "test time = 0", we get the instantaneous velocity.

This is by analogy to defining the electric field. The electric field is defined according to the force a fictional test charge would experience when placed into the field at the position at which the field intensity is to be known. Similarly, we measure a displacement that would occur during a fictional time period as that period skrinks down to the instant at which the instantaneous velocity is to be known. -- Fuzzyeric 22:48, 11 September 2006 (UTC)

Shamelessly copied from the wiki page:

The instantaneous velocity vector (v) of an object that has position at time (t) is given by x(t) can be computed as the derivative:

${\displaystyle v={\mathrm {d} x \over \mathrm {d} t}=\lim _{\Delta t\to 0}{\Delta x \over \Delta t}}$.

202.168.50.40 23:23, 11 September 2006 (UTC)

Perhaps a simple example is in order - suppose your car goes from zero to 100 mph in 10 seconds, and further suppose that the acceleration is constant over that time. Then your average speed over that time is 50 mph, but your instantaneous speed goes from 0 at the beginning to 100 at the end. For another example, which also highlights the difference between the speed and velocity, get your car up to 100 mph and drive it in a circle. Your average velocity over the whole circuit is zero - you wind up right where you started. Your instantaneous velocity is 100 mph in whatever direction you are travelling at a particular moment, and your instantaneous speed is just 100 mph. In fact, your average speed is also 100 mph, since your displacement from the starting position is 0, but your distance travelled isn't. Confusing Manifestation 00:45, 12 September 2006 (UTC)

further gravitational wave questions

I have read here that high frequency gravitational waves could be used for propulsion and moving objects, and that they could be created by quantumm effect http://arxiv.org/pdf/physics/0410022#search=%22high%20frequency%20gravity%20waves%22 Can anyone explain to me firstly how a gravity wave could move something, secondly is there even any proof that gracity waves with the force to move things even exist?

Robin

LIGO--Light current 23:23, 11 September 2006 (UTC)

No, LIGO is a (big budget) mainstream physics project; the cited eprint (surely unpublishable!) is another example of the kind of nonsense which is promoted by cranky websites like American Antigravity and GRAVWAVE LLC.. Some time back we had an article on somewhat similar claims by someone named Franklin Felber, which was deleted on the grounds that such crackpottery is very obscure and would never come up again :-/ In fact, people with more enthusiasm than knowledge keep tossing up stuff like this. See also Eugene Podkletnov.

According to general relativity, gravitational waves exist, possess energy, and can transfer momentum, but they interact very weakly with matter and are very hard to generate, for fundamental reasons. Mainstream physicists do not expect to be able to exploit them for manipulation of laboratory objects or for purposes of spacecraft propulsion. Rather, the goal of observatories like LIGO is to use (extremely weak) gravitational wave signals from very distant and very violent events to learn more about these interesting events. For a variety of reasons, gravitational waves should yield information not obtainable from electromagnetic waves. Try this.

Bottom line: just because you found it in the arXiv doesn't mean it isn't nonsense. There are many very good eprints there and unfortunately also some very bad ones.---CH 11:22, 12 September 2006 (UTC)

The big problem with using gravitational waves for propulsion is that they interact very weakly (as stated above). Some serious research has gone into the practicalities of using gravitational waves (well the fabric of spacetime really) for one very good reason. Spaceships using such a technology would not need to carry their fuel with them. Personally, I don't think it'll work. LIGO, however, might work. At the moment all we use to observe the Universe is electromagnetic radiation. Before the Universe was a certain size it was in the radiation dominated epoch. We have been unable to see anything in this epoch - it's like trying to see stars at midday. Gravitational waves wouldn't be (very much) effected by ambient radiation so we could actually 'see' objects.

Hmmmmm the article seems mainstream, do you have background in physics CH that you can say for sure that what they are proposing is crackpottery? heres another one that was apparently accepted for publication by American Institute of Physics http://www.gravwave.com/docs/Am%20Inst%20of%20Phys%20007.pdf and surely if gravitational waves usually interact waeakly surely high frequency ones would interact more strongly? since they can transfer momentum? so all EM waves can transfer momentum then? Robin

EM radiation can and does transfer momentum (p=h/λ), but from your question at the end so all EM waves can transfer momentum it sounds as if you are considering gravitational waves as a type of EM radiation which is not the case (although if you could prove it was you'd almost certainly win a Nobel Prize for your efforts). Higher frequency gravitational waves would not interact more strongly than lower frequency ones, although they would transfer more momentum in the same time period as lower frequency waves as more gravitons will be transferring momentum. The problem is actually generating these high frequency gravitational waves.
Having read only the abstract of the paper to which you linked, they don't seem to be trying to use gravitation to propel spacecraft, they are looking at using it as a method of observation/information transfer.

but if you read further they claim that high frequency gravitational fields could cause peturbations or even move objects, its in the abstact as well also move down to aplications under propulsion.. So you are saying that it is possible to move objects with an EM wave that can cause momentum tranfer of the air thus pushing the object. If high frequency gravitational waves do not work this way how wouild they move an object? Robin

Electromagnetic radiation can transfer momentum straight to the object it is moving. The articles on radiation pressure and solar sail should contain more information about that. In a quantum mechanical treatment of gravitational radiation, they would work in a similar way (although quantum gravitation is, at best, poorly understood) but this does not mean they (gravitation and electromagnitism) are part of the same phenomena. A general releativistic explanation is given in the paper.

Robert Boyle

Do you have any information on Robert Boyle?

Have you looked? obviously not--Light current 23:23, 11 September 2006 (UTC)

Yes. The best way to find it is to type "Robert Boyle" in the search box and hit the "Go" button. - Nunh-huh 23:25, 11 September 2006 (UTC)

September 12

Organ Transplant...

- Recently, someone I know was diagnosed with a serious disease. After some time, i di research on how organs can be transplanted and everything I could in my power to help. But in all seriousness, even if the information was useful, there were still some questions to ask, and my doctor would not answer:

1) How long do transplants last? 2) How effect are they? 3) What are the long term affects? 4) How much do they cost? Are there any help plans? 5) What are the chances for rejection? 6) What are the options for a person who's body is rejecting an organ? 7) If that person's body is rejecting an organ, how long do they live? 8) What steps must I take in order to prevent anything from happening ( to the person and to myself, it runs in the family)?

• Please, no pictures

- Thank you ---Sam

What do you mean how long does it last? You mean the operation to take an organ out (could be any organ), or to put it in, or how long will the organ last? If the doctors know what they are doing the organs will be 100% effective, because it is a new one. Cost depends on the organ, rejection possibilities depend on the organ, options, depend on the organ, lifespan after rejection without a new organ depends on the organ and their condition... we need more information. — (talk) (Desk|Help me improve)

Here are accurate answers to your questions based on the information you provided us. Now do you understand why your doctor didnt give you specifics? Best wishes to both of you. alteripse 01:47, 12 September 2006 (UTC)

1. Depends on the organ. If it is working at a year, chances are good for a couple of decades, more or less. #Usually if it works, it works adequately.
2. Many long term effects. Damage from malfunction before transplant. Peri- and postoperative injuries & residual effects. Long-term immunosuppression increases cancer and infection risk. Drug side effects. Long term change of life perspective from life-threatening illness.
3. Depends on where you live. Depends on where you live.
4. Chance for rejection ranges from 10 to above 50% depending on the organ, the combination of immunosuppressive drugs, the quality of the match.
5. Artificial organ substitution (various methods depending on organ) or a new transplant.
6. How long they live depends on the organ and the effectiveness of the substitution methods and any other coexisting medical problems.
7. Steps to take to prevent something happening to the person? Depends on the organ, the disease, the available treatments, and the person's access to the treatments. Steps to take to prevent something happening to you? Depends on the inheritability of the disease and your genetic relationship, or on the contagiousness of the disease and your physical relationship and infection prevention measures, or on the other effects the person's disease might have on you (missed work, expense, cancelled plans, stress, etc etc).

Just to echo the above, it really depends on the transplant. A bone marrow transplant that works lasts a lifetime. A lung transplant may only last 5-10 years. Kidneys last decades. Etc. InvictaHOG 02:45, 12 September 2006 (UTC)

Sinusitis

Quite a few years back I had serious upper respiratory problems and a medical doctor decided to run x-rays of my sinuses. One of his comments was that I have a congenital defect: both of my frontal sinuses are absent. I never learned a technical term for this condition, which I understand is unusual. He mentioned that the absence of a sinus (or in my case a pair of sinuses) is associated with sinus problems, but the causal connection was unknown. What would be the medical term for this and how would I learn more? Durova 03:24, 12 September 2006 (UTC)

bilateral frontal sinus aplasia. If you look up "paranasal sinus aplasia" in Medline you may get some articles of interest. (The relationship between anatomic variations of paranasal sinuses and chronic sinusitis in children, "Benign" imaging abnormalities in children and adolescents with headache, Anatomic risk factors for sinus disease: fact or fiction?, etc.) Medline. - Nunh-huh 03:46, 12 September 2006 (UTC)

Thank you very much. Some of the abstracts were confusing - I'm not really sure how frontal sinusitis could be associated with frontal sinus aplasia (unilateral cases?) but it seems my abnormality is far more common than I had thought. Durova 04:01, 12 September 2006 (UTC)

What did I see on September 10?

On September 10, I went outside to see the Messier 27. I sketched the nebula as well as the stars around it. Using Cartes du Ciel, I identified all but one of the stars. Here is the star I couldn't identify:

http://72.136.70.187/mystery_star.jpg (north is up, this sketch was made at 02:15 GMT on September 10)

This star was about magnitude 9.7, but Cartes du Ciel showed no stars in the region brighter than magnitude 10.8. So what was the object that I saw? If it's a star or asteroid, why didn't Cartes du Ciel show it? If it's a variable star, which variable star is it? If it's a supernova (this is extremely unlikely), why isn't there a nearby galaxy in this region of the sky? --Bowlhover 04:14, 12 September 2006 (UTC)

Have you checked the other star charts? If so and its not there, youve found a new one! 8-)--Light current 04:17, 12 September 2006 (UTC)

No, but I will soon. --Bowlhover 16:26, 12 September 2006 (UTC)

Star charts won't show asteroids, and there are hundreds of thousands of them.--Shantavira 08:42, 12 September 2006 (UTC)

Cartes du Ciel does show 500 asteroids (most of which are much fainter than magnitude 9.7). It's not an asteroid. --Bowlhover 16:26, 12 September 2006 (UTC)

Dont those usually appear in the vicinity of that gaseous planetary giant? --Light current 10:30, 12 September 2006 (UTC)

The vast majority are in the asteroid belt, but there are other asteroids all over the show. Incidentally, list of asteroids just has to be the longest list on Misplaced Pages. List of noteworthy asteroids is somewhat more interesting (and also quite long).--Shantavira 12:00, 12 September 2006 (UTC)

You misunderstand me 8-)--Light current 12:29, 12 September 2006 (UTC)

"To be great is to be misunderstood". JackofOz 13:58, 12 September 2006 (UTC)

So you meant Patrick Moore, not Jupiter?--Shantavira 15:45, 12 September 2006 (UTC)

No its the large planet beginning with U. (again) Is it Uranium? 8-)--Light current 15:48, 12 September 2006 (UTC)

I've just made a comparison image between Cartes du Ciel, and your drawn diagram. The ringed star is there - as SAO 88052 - about 8th magnitude. I've ringed in white on your diagram the mystery star. It's interesting that there's an 8th mag star missing from your diagram that is there on Cartes du Ciel. I've checked the minor planet database, and the brightest object that's on that portion of the sky at the moment is about 15th magnitude - so it's unlikely to be that. I'd say it might be a drawing error - and that the missing star on Cartes has actually been drawn - and the extra star on the diagram is probably one of the ones on the Cartes map. It's easy to get stars in the wrong place on the diagram - as you are usually drawing the position relative to some other star - and these stars are all similar in brightness and easy to confuse with each other. Richard B 20:57, 12 September 2006 (UTC)

Hmmm...I was observing with a diagonal (sorry I didn't mention that!), so did you remember to flip the image horizontally? If not...

http://72.136.70.187/cartes.jpg

And if you rotate that picture 90 degrees clockwise...

http://72.136.70.187/cartes2.jpg --Bowlhover 22:19, 12 September 2006 (UTC)

I want to know that .....

How the control unit of a CPU/PROCESSOR/MICROPROCESSOR works ? I've cearched in wikipedia and in other sites but they all provide me with the information that microprocessors are made of IC/logic gate ; several electronic gates like and,or,not are described . What's the minimum number of logic gates that can form a microprocessor of embedded system(no matter how low the processing power/speed is) ? I want to know the process by which microprocessors control an electronic devie ; how I/O ports are connected with logic gates ? How logic gates are placed in a microprocessor ? Does the control unit of embedded system do the same work done by the microprocessor of a pc in the same way ?

I want to construct a control unit(something like used in embedded system)using IC/logic gate (no problem if the processing power/speed is low) for experimental purpose ; how the IC/logic gates have to be configured ?

If I recall correctly, the control unit typically impliments microcode to control the processor. As far as the minimum number of gates - I suppose there are some processors that do not have any centrally located control unit, so 0 is the answer. Raul654 05:35, 12 September 2006 (UTC)

Start here Prepare for a long journey.

Conversion of units

I want to convert .21 Watts/meter Celsius to Watts/ meter Kelvin. Any suggestions please? -- Lost 05:40, 12 September 2006 (UTC)

They're the same. Melchoir 05:45, 12 September 2006 (UTC)

Celsius and Kelvin have the same size degrees, so no conversion is needed. Kelvin is an absolute scale, while Celsius is not, but that doesn't require a conversion here. StuRat 05:46, 12 September 2006 (UTC)

Thank you -- Lost 06:23, 12 September 2006 (UTC)

Furthermore, neither watts nor meters involve temperature., so there is no conversion anyway. ColinFine 23:14, 12 September 2006 (UTC)

Construction

Please tell me what is the name of the mixture containing cement and gravel in ratio 1:7 and used for construction.

Concrete. (Is this for real?) --Zeizmic 11:52, 12 September 2006 (UTC)

Wot? No sand?--Light current 13:06, 12 September 2006 (UTC)

Or water ? StuRat 14:25, 12 September 2006 (UTC)

Water

Why doesn't water have a taste or smell? Dismas| 13:19, 12 September 2006 (UTC)

I find it has a taste, although not very much, but maybe this is to do with impurities. Perhaps it could be linked to ph value.

Your mouth is always full of the stuff. You could say that you've gotten used to the stuff, since it's the solvent that all of your cells are perpetually bathed in. TenOfAllTrades(talk) 13:37, 12 September 2006 (UTC)

(edit conflict)What would be the evolutionary advantage of tasting, or smelling, water? If it had a taste, that taste would run the risk of overpowering any impurities you wish to taste. When water tastes, or smells, when it shouldn't, you spit it out. Saving you from possible illness. --liquidGhoul 13:41, 12 September 2006 (UTC)

Right. And that's the same reason why air doesn't have a smell (only unusual things in the air have smells). StuRat 14:24, 12 September 2006 (UTC)

Many gases are odorless, even when they are in extreme concentration compared to their concetration in air. See hydrogen and helium. --Russoc4 23:55, 12 September 2006 (UTC)

Like Hydrogen sulphide (rotten egg gas). This occurs naturally, and is very toxic, so we can smell it in very low concentrations (and it smells horrible, so we move away). --liquidGhoul 14:34, 12 September 2006 (UTC)

Aren't elephants supposed to be able to smell water many miles distant? I can certainly smell the sea when I get near it, not to speak of the local canal. Seriously though, I can smell and taste water quite easily. Sheffield water tastes much better than Birmingham water, and Norwich water tastes dreadful.--Shantavira 14:50, 12 September 2006 (UTC)

Have you tasted distilled water? The stuff I have tasted all tasted like plastic, as that is what it was in. What you are tasting between different towns is just the different salts and impurities in the water. I love the water at my mum's house, which is tank water, and is close to rain water, probably with some rust from the tank and dilute bird crap from the roof. However, town water is terrible. It reminds me of pool water. Also, the smell of the sea is the fish, salt etc. --liquidGhoul 14:57, 12 September 2006 (UTC)

Salt doesn't smell. It's an ionic solid, and has an extremely low vapour pressure. --G N Frykman 17:09, 12 September 2006 (UTC)

What is the smell of the sea than? Microorgansims? — (talk) (Desk|Help me improve)

toilet flushing on the equator

If north of the equator a toilet flushes clockwise and south of the equator it flushes counter clockwise, what happens if you flush a toilet on the equator?

It is a misconception that toilets flush differently on the northern and southern hemispheres. See the "Draining bathtubs/toilets" section in the article on the Coriolis effect. - Fredrik Johansson 15:27, 12 September 2006 (UTC)

I always liked this line of thinking as a way of dispelling the myth. Physics (the simple kind) isn't discontinuous, so there must be a band of uncertainty around the equator where the effect is too weak to determine toilet flow. And once you admit the existence of that band, why shouldn't it cover the whole globe? Melchoir 16:05, 12 September 2006 (UTC)

Careful though, it's quite common to have a discontinuity on a sphere. See Hairy ball theorem. DMacks 16:17, 12 September 2006 (UTC)

There's also spontaneous symmetry breaking. So the effect could be ambiguous in some places and not in others. -- Fuzzyeric 16:19, 12 September 2006 (UTC)

Yes yes, I know. But the Coriolis force is elementary stuff. It doesn't involve any complex systems, nor is its magnitude prevented from falling to zero. So it really should be overpowered by other effects at the equator, and lo and behold, it is. Melchoir 16:47, 12 September 2006 (UTC)

Bird's Sight

What are the characteristics of a bird's eye that give them such excellant vision?66.151.82.105 15:24, 12 September 2006 (UTC)RW McNamara

<--email removed to prevent spam-->

According to our article on bird anatomy, "Birds have acute eyesight, with raptors having vision eight times sharper than humans. This is because of many photoreceptors in the retina (up to 1,000,000 per square mm in Buteos, against 200,000 for humans), a very high number of nerves connecting the receptors to the brain, a second set of eye muscles not found in other animals, and, in birds of prey, an indented fovea which magnifies the central part of the visual field. Many species, including hummingbirds and albatrosses, have two foveas in each eye, and the ability to detect polarised light is also common."--Shantavira 15:38, 12 September 2006 (UTC)

Why would a bird need to differentiate polarized light? — (talk) (Desk|Help me improve)

Googling for bird "polarized light" reveals that it's useful for navigation. There's some more information about natural sources of polarized light in the Polarized light page. DMacks 16:01, 12 September 2006 (UTC)

Elasticity

which is more elastic rubber or steel? why?

Please take a moment to review with the instructions at the top of the page. We're pleased to help out with most questions, but I'm afraid that we have to ask you to 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. TenOfAllTrades(talk) 16:31, 12 September 2006 (UTC)

you dont know that thats a homework question. many questions asked here are far more complicated and homework looking. hes only asked 1 question and the reason why.--86.141.230.129 17:14, 12 September 2006 (UTC)

I beg to differ. Asking whether rubber or steel is more elastic is a transparently obvious homework question. That said, the answer is easily found in your textbook or a dictionary. — Lomn | Talk 17:25, 12 September 2006 (UTC)

If you're really stuck, click on the links I put in your question, or use the search box. Or just look up elasticity in a dictionary.--Shantavira 17:29, 12 September 2006 (UTC)

Please try before you ask for help. — (talk) (Desk|Help me improve)

What do you think an elastic band is more likely to be made out of, rubber, or steel?Tuckerekcut 22:55, 12 September 2006 (UTC)

Also see Young's modulus. If you can understand the article, the table indicates which material has the higher elasticity.--Light current 23:04, 12 September 2006 (UTC)

Well I don't know, squish a piece of steel, and a rubber ball and see which one snaps back into shape. Deltacom1515 02:05, 13 September 2006 (UTC)

Acrylamide in sultanas and other dried fruits

As a health precaution, until there is further clarification on if acrylamide is carcinogenic or not, I'm trying to avoid things containing it.

Can anyone tell me please how much acrylamide there is in sultanas - a form of dried grape. I have searched on the internet and emailed a sultana wholesaler about this without success.

There is a lot of acrylamide in prune juice - a prune is a dried plum. The browning process - possibly the Maillard reaction - creates acrylamide. Sultanas are dried grapes and undergo browning - they could also have similar levels of acrylamide (yes, I know grapes are otherwise good for you). Does anyone know for sure please? 81.104.12.39 18:39, 12 September 2006 (UTC)

Almost all natural food contains some sort of carcinogen. It's just that the other stuff usually makes up for it. Prunes are one of the healthiest things going (if consumed as part of a varied diet). To avoid all bad stuff, I suggest that you just eat highly purified sucrose. --Zeizmic 20:04, 12 September 2006 (UTC)

I disagree with all of your assertions. I'm looking for facts rather than homely armchair speculation please.

The fact of the matter is you would have to work rather hard to get all the acrylamide out of your foods. but from memory acrylamide is mainly an issue in foods cooked at high temperatures eg deep fried foods. the levels in most fruits etc seem to be quite low, , but sultanas aren't listed. Xcomradex 22:18, 12 September 2006 (UTC)

Also, there is a great difference in toxicity and carcinogenicity between free acrylamide and polyacrilamide. If it is in the polymer form in the fruit you mention, the acrylamide will be harmless.Tuckerekcut 22:53, 12 September 2006 (UTC)

Myocardium (heart muscles)

72.70.136.195 18:50, 12 September 2006 (UTC)How would aerobic excercise strengthen the heart? Is the heart muscle fast or slow twitch?There is an excercise movement called "Superslow" that teaches that aerobics are more harmfull than good, but that to build and strengthen skeletal muscles will make the heart efficient. This philosophy also teaches that the heart of an athlete pumps very little more blood per beat than a couch potatoe's heart. I know aerobics can do a lot of harm to joints. The aerobics also train the muscles in motor skills that make it "seem" like the heart is stronger. The point is, if the "Superslow" people are correct, then aerobics would definitley be unecessary. However, it seems walking is good for stress reduction, and a small amount of calorie burn. Bottom line is, "How" does aerbic activity really help the heart? Thanks to those who know the answer. Rich Stone

Aerobic exercise increases vascularization and (to a lesser extent) density of heart muscle. The increase in vascularization allows increases anastomization (redundant blood flow) and imparts resistance to ischemia (loss of blood perfusion). The amount of blood pumped by the heart depends on a lot of factors and is not a good indicator of overall health. The isolation of skeletal muscles in any exercise routine will not develop the heart muscle properly, and in extreme cases will be detrimental, as the increased stress introduced by growing muscles will not be matched by a stronger heart. In general, the heart will do its job just fine as long as it is "fed" properly. See myocardium, smooth muscle, atherosclerosis, aerobic exercise, and anaerobic exercise for more information.Tuckerekcut 22:48, 12 September 2006 (UTC)

Inertia

Is inertia a property of matter, or a force of some kind?

I think it's neither, really, but rather a corollary of the principle of relativity (the fundamental principle, as opposed to the consequences derived by Einstein). --Allen 19:26, 12 September 2006 (UTC)

Inertia is a property of matter. It is the property by which a body continues to move with constant velocity unless acted upon by an external force and comes from Newton's first law.

See the page talk:Inertia. This topic has been done to death there a number of times. --Light current 20:17, 12 September 2006 (UTC)

Newton's laws

I need help to explain my son's homework. A common saying goes," it's not the fall that hurts you; it's the sudden stop." Can you translate this into Newton's laws of motion? THANKS.

An object in motion tends to stay in motion. When you hit the ground, whatever body part touches first stops first. But the rest of you keeps going, tearing and crushing your organs. (The fall itself (through the air) is no problem -- you're changing speed as you fall, but your different body parts are changing speed together, so your body stays intact.) --Allen 19:32, 12 September 2006 (UTC)

velocity

When your car moves along the highway at constant velocity, the net force on it is zero. Then why do we continue running our engine?

We wouldn't have to, except for friction. --Allen 19:27, 12 September 2006 (UTC)

Think of it like this: The car is moving at a constant velocity because the engine is pushing it forwards, while friction is resisting this movement. The two forces are balanced, if they weren't, the car would either speed up or slow down. Gary 19:42, 12 September 2006 (UTC)

In fact, your highway gas mileage is almost totally dependent on the air friction. That is why sports cars with huge engines are very thrifty on gas on the highway. --Zeizmic 20:06, 12 September 2006 (UTC)

The Drag equation approximates the force experienced by an object moving through a fluid at relatively large velocity. The equation is attributed to Lord Rayleigh, who originally used ${\displaystyle L^{2}\ }$ in place of ${\displaystyle A\ }$ (L being some length). The force on a moving object due to a fluid is:

${\displaystyle \mathbf {F} _{d}=-{1 \over 2}\rho v^{2}AC_{d}\mathbf {\hat {v}} }$    

where

F_d is the force of drag,

ρ is the density of the fluid (Note that for the Earth's atmosphere, the density can be found using the barometric formula),

v is the velocity of the object relative to the fluid,

A is the reference area, and

C_d is the drag coefficient (a dimensionless constant, e.g. 0.25 to 0.45 for a car).

The reference area A is related to, but not exactly equal to, the area of the projection of the object on a plane perpendicular to the direction of motion (ie cross-sectional area). Sometimes different reference areas are given for the same object in which case a drag coefficient corresponding to each of these different areas must be given. The reference for a wing would be the plane area rather than the frontal area.

The power required to overcome the aerodynamic drag is given by:

${\displaystyle P_{d}=\mathbf {F} _{d}\cdot \mathbf {v} =-{1 \over 2}\rho v^{3}AC_{d}}$

Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Since power is the rate of doing work, exerting four times the force at twice the speed requires eight times the power. Of course, if you are going twice as fast, you would get to your destination in half the time. Thus the total energy consumption would be 4 times higher (instead of 8 times higher).

Inorganic Chemistry

What would be the transition energy in units of eV from the ground state to the second excited state of the Li(2+) ion? I'm more interested in an explination than an answer. Thanks! 130.207.180.37 20:02, 12 September 2006 (UTC) Dave

Question about energy states / emission spectrum of hydrogen

What is the position of the third line in the visible portion of the emission spectrum of atomic hydrogen, ie in Angstroms in wavenumbers? I just need a helping hand with this question more than anything else. Thx in advance! ~ Mark P.

"Cause of Death"

I lost my brother about two and a half years ago in a car crash. He was driving alone and no one else was hurt. He simply lost control of his car on a patch of black ice and crashed into a utility pole. The attending doctor at the ER told me that the "cause of death" was a heart-attack. Yet my brother was in his 30's, and had no previous heart condition whatsoever. I wasn't in the mood to ask questions so I just left it at that. But over the past while I've been wondering about exactly what he meant when he said that the "cause of death" was a heart-attack. At first I assumed what appeared to be the most obvious: he was driving, had a heart-attack for whatever reason, and as a result of his heart attack he was inacapacitated and could no longer effectively control his car.

But then it occured to me that I may have it all wrong. Perhaps, when a healthy person suffers such a severe trauma to his body, perhaps the trauma causes the heart-attack. In other words, first he lost control of the car, then smashed into the pole, and only then, due to the trauma of the crash, did the heart-attack occur. Or perhaps even more simply, due to the crash, his heart simply stopped for whatever reason, and therefore, the "cause of death" was considered to be a heart-attack.

I'm wondering if there's anyone out there who may work in an ER, or somehow have knowledge of this sort. If a healthy person gets into a fatal car crash, what are the most likely terms used for the "cause of death"? Excluding instances where the heart-attack actually occurs prior to the trauma, is it rather common for a heart-attack to be considered the "cause of death" after the trauma occurs? Thanks. Loomis 21:07, 12 September 2006 (UTC)

I've heard it several times before. Silent ischemia can happen after trauma (cause as well?) — (talk) (Desk|Help me improve)

It is likely that the ER doc was talking about a pericardial tamponade. This is a catastrophic bleeding into the sac surrounding the heart which rapidly causes cardiac arrest. Tamponade occurs frequently in car crashes because the ligament (the ligamentum arteriosum) which connects two large blood vessels just above the heart often rips a hole in one of those vessels when the heart itself jerks out of place at the moment of impact. Blood fills the sac and prevents the heart from stretching and relaxing as it should. This is by a wide margin the most likely cause of cardiac arrest after trauma.Tuckerekcut 22:37, 12 September 2006 (UTC)

Yea, the guy that US Vice President Dick Cheney shot had a similar, trauma-induced heart attack. StuRat 22:50, 12 September 2006 (UTC)

Dick Cheney and a hunter friend walk into some foggy woods, and his friend remarks at how scary the woods are. Cheney replies "You think you're scared ? I'm the one who has to walk back out of these woods all alone !". StuRat 22:50, 12 September 2006 (UTC)

The heart attack suffered by Harry Whittington was due to a pellet from Cheney's shotgun that lodged in the outer tissues of his heart. Probably the metal in the pellet altered the endogenous electrical ativity therein, causing atrial fibrillation. This is a completely different pathology, and can only loosely be considered "trauma".Tuckerekcut 23:02, 12 September 2006 (UTC)

Io MOTH

We have an Io Moth which has made a cocoon withing the oak leaves I gave it. It has been wrapped up in cocoon since Saturday, Sept 2. How long will it remain in the cocoon stage before it erupts and becomes the adult moth? We want to prepare it a branch that it can climb upon.

PSS World Medical

Hey I was wondering if there was any information about PSS World Medical Inc, which is an organisation in America that supplies doctors and hospitals with medical supplies that they need?

Stroking a parrot?

Why do parrots like having their heads stroked but freak out if you touch their backs, wings or stomaches?

My bird loves to have her beak stroked, but not he rwings or stomach. Some birds like to be pet anywhere. It all depends on how the bird was handled after they hatched. If they get used to certain touches, they will be more accepting, but if you get a parrot after they have been raised for a few months or so, and it wasn't made acustom to certain touches, then it never will get used to them. My bird also fears gloves and socks, leaving us to believe that she may have been handled by someone wearing gloves and has had a bad experience. Just an assumtion, not necessarily true. --Russoc4 23:52, 12 September 2006 (UTC)

Getting my head shaved - pros and cons?

Anyone know? Thnx.

havent we had a similar question quite recently?--Light current 23:23, 12 September 2006 (UTC)

(edit conflict) Do you mean actual head shaving, where all the hair is shaved off, or a buzz cut, where hair is cut very short (usually 2cm or less), or a "high and tight" which is sort of a mixture of the two? If you are balding, you may want to go with the first option. A buzz cut is vary easy to maintain (low maintenance). —EdGl 23:34, 12 September 2006 (UTC)

Pros:

• You'll look like a tough guy.
• You can wash your hair with a sponge.
• No more messing around with combs and gel.

Cons:

• Some drunken arsehole might try to start a fight with you because you look like a tough guy.
• Sunburn on the scalp.
• People patting you on the head as they walk past.
• You *may* end up looking like Mr. Potato Head.
• If your face is fat, it'll look even fatter.

--Kurt Shaped Box 23:58, 12 September 2006 (UTC)

Small bass cab

Anyone know of a commercially available bass cabinet (or combo), less than 1 cu ft, that will reproduce frequencies down to about 40 Hz @ -3dB?--Light current 23:31, 12 September 2006 (UTC)

September 13

How do you define Pica?

I read the article about Pica and I want to know more about this disorder. I know a lot of people who like to eat stuff that normally would be considered gross, like raw potato and powdered milk. Is it always a disorder when you eat things like that? I like to eat paper, in little bits at a time. Is this Pica? Should I stop doing it? Even if it is Pica, is paper dangerous to eat? --Jonathan 00:06, 13 September 2006 (UTC)

Does it decrease your quality of life? If not, don't worry about it. But please, stay away from bleached paper. Paper itself is pretty much just insoluble fiber (cellulose) but the chemicals they use to bleach it include some pretty nasty species (most famously, members of the dioxin family).Tuckerekcut 01:48, 13 September 2006 (UTC)

Psychology and Human Viruses

I am in the 12th grade and I am very interested in Human Viruses. Now i need to write a paper in Psychology about theories such as Gestalt Theory, Psychology of Lieing "Why people lie" and "Nature vs. Nurture" and such. It can basicly be anything that involves psychology. Now I wanna tie in Psychology and human viruses such as I dont know, How they form or the affect of the human body from human viruses. I believe I need a theory that I need to disprove/prove. As long as it involves human viruses and I can write a paper about it im fine with it. So basicly my question is, Is there any psychological theory about human viruses? and what is it?

Thanks in Advance for any help.

--Coolguy 1175 00:22, 13 September 2006 (UTC)

One of my favorite psychologists, Claude Steele, once did a study on alcohol and safe sex. Basically, he was trying to show that alcohol, rather than being simply a disinhibitor, more accurately serves to narrow one's attention. Narrowing one's attention generally has a disinhibitory effect, but not always. Steele showed that if you put an card with warnings about HIV in front of a drunk, they'll actually be less likely (at least according to their own predictions) to have unsafe sex that night than a sober person presented with the same card. (HIV being a virus. :-))

Another angle: even though almost all medical scientists are sure that the benefits of immunization (against viruses) far outweigh the risks, a lot of parents won't allow their children to be immunized. What motivates these anti-vaccinationists? --Allen 00:56, 13 September 2006 (UTC)

Other articles I should have linked to (it seems we have relatively poor organization on this topic): Vaccination, Vaccine controversy --Allen 01:04, 13 September 2006 (UTC)