Wikipedia:Reference desk/Science

July 18

Relationship between electron affinity and ionization energy levels

Is the ionization energy of an atom related to it's electron affinity? For example, chlorine has an electron affinity of 349 and a first ionization energy of 1251 (in kJ/mol). But would the first ionization energy of Cl+ be equal to 349 kJ/mol? Likewise, would the electron affinity of Cl- be related to that first ionization energy of Cl neutral? Thanks! Delta 02:44, 18 July 2007 (UTC)

You are correct in that there is a relationship, but I think you got the specifics wrong. The electron affinity of Cl would be equal to the first ionization energy of Cl-. Why? Because the reaction for the electron affinity of Cl is as follows: Cl + e- --> Cl- (-349 kJ/mol), while the exact reverse of that reaction is the first ionization energy of Cl-: Cl- --> Cl + e- (energy is therefore the opposite, or +349 kJ/mol). ugen64 06:19, 18 July 2007 (UTC)

Frequent Urination

Since yesterday, i have been urinating a lot. I don't have diabetes and I've been cutting down on my fluids, but I'm still going a lot. Any ideas why? BTW, my urine is clear if it makes a difference.71.218.37.80 04:22, 18 July 2007 (UTC)

We have an article on this at polyuria. However, Wikipedia cannot offer a medical diagnosis, so if you are concerned about the frequency of your urinations, please consult a doctor. Someguy1221 04:44, 18 July 2007 (UTC)

Any pharmacy (chemist) sells little test strips for detecting sugar in urine. Just saying. Edison 01:26, 19 July 2007 (UTC)

Diabetes mellitus says that Type 2 diabetes can go undetected for years, with intermittent symptoms. Unless you have seen your doctor since the onset of the abnormally frequent urination, you probably are not justified in stating that you do not have the condition. Edison 18:07, 19 July 2007 (UTC)

See a Dr. first. Second you might have prostrate problems if you are male that is. Frequent urination but not in large volumes is a symptom of enlarged prostrate (it might even be cancer, I pray not for you! amen). Best wishes! TripleBatteryLife 15:43, 23 July 2007 (UTC)

Waterdrops- Perfume spray

Always when I was spraying the perfume (aerosol metallic tin) I was noticing some thing unusual.. after spraying some drops are being accumulated around the nozzle even though I wiped it away it was appearing for second time..why this was happening? Temuzion 06:56, 18 July 2007 (UTC)

It could be due to the depressurising gas in the aerosol being very cold due to adiabatic expansion. This will chill the nozzle, which will get condensation from humidity in the air. GB 07:17, 18 July 2007 (UTC)

Yes the expansion of the gas will take lot of heat from the can therefore making it cold and encourages condensation. Don't do this on someone (they can get frostbite from it) but if you tip the can upside down the gas bypasses the heatsink of the can and gives out very cold aerosol, which will create a mist-like stream coming out of the nozzle. --antilived^{T | C | G} 07:34, 18 July 2007 (UTC)

A more noticeable effect can be demonstrated by letting air out of a car tire. Since the air is under pressure and it expands after being let out, according to the Ideal gas law there should be a corresponding drop in temperature. You can feel the nozzle drop in temperature as you let out the air. (Just don't let anyone catch you giving them a flat tire.) -- JSBillings 13:18, 18 July 2007 (UTC)

Excess drinking of water!

Since one week I was drinking high amounts of water..even though I'm not thristy I was forcing myself to pour in some litres of water every day..when ever I remember water I was drinking minimum 1&half litres of water..in that way I was intaking some 6-8 lts of water daily..& similarly i was urinating very frequently.. which kind of effect will be shown on my body by this new habit? I hope it'll be definitely +ve..! Temuzion 07:03, 18 July 2007 (UTC)

A) Wikipedia cannot give medical advice. B) Water intoxication is a potentially fatal condition brought on by drinking too much water too quickly. Dragons flight 07:11, 18 July 2007 (UTC)

The font of all medical knowledge, House, showed that this can mess you up real bad. All I remember is that the guy had crippling muscle cramps - It doesn't say much about this, but the episode was House_vs._God, I think. Aaadddaaammm 07:57, 18 July 2007 (UTC)

In the end it turned out he had herpes; he was drinking the excess water in an attempt to 'cleanse' himself of his guilt and the virus, nothing to do with water intoxication. Lanfear's Bane

Except that his symptoms are that of the water intoxication, so it has everything to do with water intoxication. Capuchin 09:00, 18 July 2007 (UTC)

See Jennifer Strange. Not a nice way to die. --S.dedalus 22:00, 18 July 2007 (UTC)

See the Q & A about "Frequent urination" above. Edison 18:08, 19 July 2007 (UTC)

Number of Perpetual Motion Machine Patents?

Hello,

Is there anywhere it is possible to find out the number of patents for perpetual motion machines that are filed in a given year?

--91.104.48.234 07:24, 18 July 2007 (UTC)

I'd guess so. The WIPO maintains the International Patent Classification (IPC) which it used by patent offices around the world to classify patents. The purpose is, of course, to help in searching: you can quickly look up what patents have been filed or granted in a certain subfield. A quick look at the IPC's index ("catchwords" in their lingo) shows you that there are four keys for "perpetua mobile, alledged". Now, you just have to find out how to search for all patents with a given ICP classification key on one of the public web sites offering access to patent databases (on the USPTO, for example, or with Google Patents) and count. There is only one catch: If you search in a database for granted patents, you won't find much, because in most jurisdictions patent offices may refuse to deal with perpetua mobile and reject them by default. So, you have to find a way to search through the database of filed applications, not of granted patents. This information is public, too, but maybe not as readily accessible. Have fun and tell us what you found. Simon A. 07:47, 18 July 2007 (UTC)

Yes, you cannot be granted a patent for something which defies the known laws of physics. Capuchin 07:50, 18 July 2007 (UTC)

I am not arguing for the perpetual machine here (I know it can not be built), but out of curiosity: How can they not grant patent for something just because they don't understand what it is or how it works, just because it does not conform to the known laws of physics? It is always possible for someone to come up with something which defies all known laws. Take the example of the idea of matter waves or the theory that sun is at the center of the solar system. Till these were proposed, people had different ideas. What is the rationale behind refusing patents? -- WikiCheng | Talk 09:57, 18 July 2007 (UTC)

This is exactly the problem that steorn is facing. They have had to patent each part of their device seperately, as they cannot patent the device as a whole. They claim that it creates energy, but have yet to form an explanation of how it works. I must admit, this is the only example that I have knowledge of patenting free energy machines from. (They have yet to demonstrate it in public, and i'm fully expecting for the source of the energy to be found, if it does indeed work). I would be happy to be proved wrong. Capuchin 10:21, 18 July 2007 (UTC)

A patent is essentially a trade between the inventor and the government: the government grants a temporary monopoly, and in return, the inventor teaches the public how the invention works, or more precisely, provides a description that allows a person skilled in the art to practice the invention. Ordinarily patent offices take the inventor's word that the invention will work, but in exceptional cases, can demand working prototypes. So you can't invent a perpetual motion machine and at the same time keep secret how to build one that works. Also, inventions must be useful. A perpetual motion machine that merely moves, but does not allow one to extract any energy from it, might not be considered useful. --Gerry Ashton 13:26, 18 July 2007 (UTC)

It's actually a tough thing about patent offices and always has been — on the one hand, they are expecting the devices to be on the cutting edge and thus not necessarily conforming to standard understandings; on the other hand, they are also on the lookout for tricksters, hucksters, and frauds, all of whom could exploit a poorly granted patent for their personal and economic gain, at the expense of others. That's why the patent office has its own experts who are trained to examine patents to see if they would work, to see if they have obvious fallacies in them, to see if they are just preposterous or not. Patents are supposed to be written in a way which means that anyone skilled in the art can understand how they work, and the patent examiner is presumably skilled in the art. Does it always work? Of course not — there are a lot of factors going into whether a patent is granted (according to these guys, the US patent system today grants patents far too easily because the examiners are overburdened and only get punished if they don't grant enough patents, not if they grant too many bad ones), but that's the general idea. --24.147.86.187 13:51, 18 July 2007 (UTC)

The biggest problem in finding such things is that since the USPTO explicitly says it won't grant patents on perpetual motion machines, no patentee with half a brain would make it clear that this is what they were trying to patent. They will try as hard as possible to make them look like standard electrical/mechanical devices, and to cloud the fact that they apparently violate the first law of thermodynamics (conservation of energy: it's not just a good idea, it's the law!). So you're basically looking at something which will be, rationally speaking, deliberate obfuscated. Which isn't impossible — but it's not easy! --24.147.86.187 13:57, 18 July 2007 (UTC)

Our article on Motionless Electromagnetic Generator gives a link to one such patent. So I count 1. Capuchin 14:09, 18 July 2007 (UTC)

"Yes, you cannot be granted a patent for something which defies the known laws of physics." - actually, as described in our article, with the specific exception of prepetual motion machines, you can: With the exception of cases involving perpetual motion, a model is not ordinarily required by the Office to demonstrate the operability of a device. If operability of a device is questioned, the applicant must establish it to the satisfaction of the examiner, but he or she may choose his or her own way of so doing. - http://www.uspto.gov/web/offices/pac/mpep/documents/0600_608_03.htm I can't remember where I read it, but a non-trivial percentage (something like a quarter) are for things that do not work. Raul654 14:09, 18 July 2007 (UTC)

Great, thank you for correcting me! Capuchin 14:10, 18 July 2007 (UTC)

Raul654, thanks for taken over the job of clarifying this mess. A few additions: A Raul correctly points out, the patent office's job is only to check whether the invention is new, i.e. that there is no prior art and that it is sufficiently non-obvious. There is no need at all to check, whether it would work, and there is no point to checking that. After all, if the state grants the inventor a monopoly in exploiting a useless invention in exchange for the inventor's paying patent fees to the state, this is no loss for the society and only the inventor's problem. Given that most patents are filed as soon as the idea is there, before it has been worked out sufficiently in details to even think of making a prototype, it would also be hard to show conclusively that it works. Now, the fact that most countries' patent laws explicitly exclude perpetua mobiles from patenting is, of course, an exemption to the rule that checking the soundness of an invention is not the patent office's business. The reason for this exception is, I think, just a courtesy to the poor patent examiners for whom the amusement value of having to deal with cranks might wear off pretty quickly. Furthermore, it is rather hard to judge whether one pertuum mobile is an invention that goes beyond another pertuum mobile invention in a non-obvious way, if the person having ordinary skill in the art would find both inventions equally stupid, and asking courts to check such jedgement would be quite a waste of time. So, the original poster was quite right in asking not how many patents on pertua mobile are granted but how many are filed. Given that all filed patent applications are made public already before they are examined by the patent office, it should be possible to count all the declined perpetuum mobile claims. Simon A. 17:00, 18 July 2007 (UTC)

TRUE PERPETUAL MOTION IS IMPOSSIBLE because even the sun will eventually run down (billions of years from now). BUT Psuedo PM is possible of a sorts. Example there is a clock in the smithsonian that runs perpetually on the motion of the earth. Solar cells can perpetually provide power as long as the sun rises everyday. Ocean tide generators , same, as long as there are tides. ect .ect. Beware the snamp (new word = snake x scam) who would separate you from your bank acct. lol TripleBatteryLife 15:48, 23 July 2007 (UTC)

Kent Couch - Lawn Chair Balloons - did he really go up to 13,000+ feet?

I saw Kent Couch, on a nightly talk show explaining his journey over Oregon and he said he got to altitudes of 15,000 feet. However, several articles I read online stated he got up to 13,000. I do not doubt that he made this trip in his lawn chair, but I am hightly skeptical of the altitude. He claims he used no supplumental oxygen at all. Some of the articles also stated that despite being so high he could even hear cows mooing. So, was he really that high? Would he be able to breath fine and not be sick during an 8 or 9 hour trip up in the air? Also, isn't it quite cold up at that altitude? I'd appreciate any references or further information. Thanks.

Have you looked at our article on Kent Couch? It gives his altitude as 3 miles (15840 ft). A lot of the information that is useful to you can be found in the outer space article. This has a list of the important point in the atmosphere. It gives 15,100ft as the point in the atmosphere where the FAA requires supplemental oxygen. It's not until 26,200 ft that you reach the death zone. Altitude sickness can occur at 6,500ft. I don't know if he was affected.

This page shows that it would be about 3 degrees celcius, so not too cold (that's not exactly a reliable source, but I couldnt be bothered to find a better one). I think it's certainly plausible. There's even more information and lots of sources on Larry Walters, who also went up to 16,000 ft in a lawnchair. Capuchin 08:19, 18 July 2007 (UTC)

Speaking from personal experience, I've been to the summit of Mauna Kea in Hawaii as part of a tour ([1]) a number of years ago. The summit is at just shy of 14,000 feet (4200 m), and most people have no trouble with it. (The tour operators reject visitors with heart or lung conditions, pregnant women, the morbidly obese, and children under 13—though the last group may just be because kids would get bored on the long drive up the mountain.) So yes—it's certainly quite possible and reasonable to breathe comfortably at that altitude.

Of course, as Capuchin notes it's apt to be cold. In Hawaii, in August, we were all glad to have warm fluffy coats when we were at the summit. It was above freezing, but not by much. TenOfAllTrades(talk) 13:31, 18 July 2007 (UTC)

Also note that international badass Reinhold Messner climbed Mount Everest (29,000 feet) with no oxygen, and presumably you need a lot more oxygen to climb a mountain than to sit in a lawn chair. --TotoBaggins 15:17, 18 July 2007 (UTC)

15,000 feet isn't too high - there are several towns in the world up at this altitude (Le Riconada, Peru is at 16,700 feet). Mt.Everest is 29,000 feet - so you're a long way from that kind of problem. He's not exactly exerting himself - so oxygen ought not to be a problem. It would be pretty cold though. The rule-of-thumb is that you get a temp drop of 6.5 degC per 1000m of altitude. So he was looking at a temperature drop of maybe 30 degrees C - it would be freezing - but he'd be OK if he was properly dressed for it. SteveBaker 18:36, 18 July 2007 (UTC)

IT was 1,300 feet not 13,000. (newspaper article). TripleBatteryLife 18:54, 24 July 2007 (UTC)

Arctic Fox

My daughter needs to do a project on hibernation and the Arctic Fox was presented by her teacher as one example of an animal that hibernates. I don't find a sigle reference to the hibernation of the Arctic Fox and infact, found an article indicating that the Artic Fox does not hibernate - can you kindly clarify. Thanks.

You are correct, the Arctic Fox does not hibernate. In fact the article has pictures of its different seasonal coats. Lanfear's Bane

I'm pretty sure that only the hibernating animal in the arctic is the Arctic Ground Squirrel. Some say that pregnant female polar bears hibernate, but it is debatable whether this is hibernation in the true sense. --GTPoompt(talk) 12:59, 18 July 2007 (UTC)

Perhaps you could tell your daughter's teacher that she/he made a mistake. Hibernation is a form of defense against cold, harsh weather; the Artic Fox is suited for cold weather, so it would never hibernate. Cheers!!! --Zacharycrimsonwolf 13:39, 18 July 2007 (UTC)

Why would an animal that hibernates change its coat color to match the snow? Gzuckier 19:02, 18 July 2007 (UTC)

This page says:

black and brown bears are just two of the seven mammals that curl up in dens or burrows or otherwise slumber through Alaska’s cold, dark season. The others are Alaska marmots, hoary marmots, woodchucks, arctic ground squirrels and brown bats, according to Loren Buck, a professor of biology at the University of Alaska Anchorage.

, but I don't know which of those critters occur in Alaska's sliver of Arctic.

Separately, a note of caution: I have encountered both in my own education and in my daughter's some teachers who do not appreciate being corrected on any subject. It's unfortunate, but true, so I would advise tact and discretion on your daughter's part. --TotoBaggins 15:26, 18 July 2007 (UTC)

Yeah - I can definitely agree with that whilst you have a responsibility to get to the truth, it's going to be painful. We've had long and hard arguments with teachers - extending up to principals when my son has given the correct answer and the teacher (and very often the textbooks) are wrong. It's not so bad when the teacher is wrong and the textbook is right - or vice-versa - but when both teacher and textbook are wrong, you're in for a hard time! (eg: Here are a whole bunch of triangles, list which triangles are isocelese, list which triangles are equilateral. My kid listed the equilateral triangle in both the equilateral list AND the isosceles list. The teacher said "No" that's an equilateral triangle - it's not isoscelese. The teacher's answerbook agreed with her. It took a month, three letters (one backed up by a college math professor!) one meeting with the teacher and one more with the principle to get them to agree and to change his grade. Then we had "Which is the odd word out: Orange, Apple, Pear, Tomato" - the official answer was "Tomato"...because "it's a vegetable"...well, I'm sorry but a Tomato is a fruit just like the others. My son not only knew this but chose "Orange" as the answer because "All of the others have rhymes - but nothing rhymes with orange". When told he was wrong he offered "Apple" because it's the only word that doesn't have an even number of letters and the only one with two successive identical letters - but conceded that perhaps "Pear" might be correct because it's the only word whose first letter is not symmetrical - and the only one that doesn't end in a vowel and the only one with two consecutive vowels. When he said it was an ambiguous question he got kicked out of class for being disruptive. (The question was "Which word" was the odd one out - so arguably the question wasn't about fruit anyway.) SteveBaker 18:32, 18 July 2007 (UTC)

Hahaha, I had that happen before. A teacher that insisted Mexico was part of South America, amongst other things I don't remember. I've had stupid teachers, but they weren't totally wrong that often. What your kid did though, Steve, is just plain awesome :D --L^augh! 18:38, 18 July 2007 (UTC)

Funny, and fun, and perfectly correct, but you might also want to inform him that "how to jump through the correct hoops" is also a valuable life skill. A teacher could be forgiven for finding a child's assertion that the object at right is called a "rectangle" to be deliberately obtuse, especially when multiplied by 20 kids in the class or whatever. --TotoBaggins 18:57, 18 July 2007 (UTC)

I remember my eighth grade science teacher informing us that ultraviolet light was yellow in color. Even in eighth grade I figured, WTF? Gzuckier 19:08, 18 July 2007 (UTC)

That's an unfortunate fact of life; "bright" kids, i.e. intelligent and/or original, can see a bunch of patterns, not just one. It would be vastly different if the question had some kind of point to it; i.e., "Which is the odd word out: Orange, Apple, Pear, Tomato, if you were writing a poem?" Just visited a classroom in a pretty good public school, but compared to a pretty good local private school, you can still tell the difference. Teacher in the public school classroom: "We're going to decorate these now. What's a nice shape to decorate with?" Happy, eager kindergartener: "Snowflakes!" Teacher: "But we don't see snowflakes in the summer. How about something else?" Gzuckier 19:08, 18 July 2007 (UTC)

I particularly enjoyed the textbook in year 6 which is now correct, sort of. The book, my teacher and everyone else on my table insisted that Mercury was the smallest planet. How I gloated, months later, when we got new books in secondary school that backed me up. If the book had just missed Pluto out altogether you could use it today :/ And in Britain at least, it's not a private/state thing I think. On the other hand, I knew someone at a private school who got their teacher in serious trouble through a reverse of this; the teacher kept marking their work as correct without checking, so they started making things up to see what would happen. What happened was terribly embarrasing. Skittle 21:42, 18 July 2007 (UTC)

On that last point, see this news story. --Anonymous, July 19, 02:54 (UTC)>

It is the duty of the student

Without question to be prudent.

If smarter than the teacher, tact

Demands that he conceal the fact.

-- Hilaire Belloc [I think --scs 17:18, 20 July 2007 (UTC)]

I had to face the wrath of my math teacher in 8th standard for arguing that the diagonals of a square cross at right angles. She had mentioned that rhombus is the only quadrilateral with this property. She did not seem to be in a mood to appreciate the fact that square is a rhombus, exactly because of this property. Needless to say, I didn't get a chance to prove what I said -- WikiCheng | Talk 06:29, 19 July 2007 (UTC)

Her original statement was wrong. A "kite-shape" (any quadrilateral composed of two isosceles triangles sharing a base) has perpendicular diagonals. Any rhombus is a "kite-shape", and any square is a rhombus. -Arch dude 12:48, 19 July 2007 (UTC)

Isn't even "kite-shape" is an incomplete answer? Stop restricting yourself to where either of the two diagonals bisects the other and you have...an irregular mess. Could be a quadrilateral with no pairs of congruent or parallel sides and no right angles or pairs of congruent angles. DMacks 13:24, 19 July 2007 (UTC)

That's true - I suspect she meant to stipulate that the diagonals had to bisect each other at their midpoints and at right angles. That's what gets you a rhombus - but she's still in trouble for not knowing that a square is merely a special case of a rhombus. That business of special cases not being allowed to take the name of the more general object was my kid's problem with isoscelese triangles and equilateral triangles. The trouble is that once you accept that, nearly all of the class must now be told they got it wrong even though the textbook says they are right. Teachers must just hate smart kids! (Erm...and we've strayed a bit off-topic here haven't we!) SteveBaker 21:48, 19 July 2007 (UTC)

night in the northern hemisphere

Is it possible for the whole of northern hemisphere to have night at the same time ? -- Myth (Talk) 13:25, 18 July 2007 (UTC)

no. the south pole would have to be pointing towards the sun. that will not happen unless something HUGE happens to change the way the Earth rotates. Capuchin 13:33, 18 July 2007 (UTC)

I suppose if you could tilt the whole earth so the north pole points away from the sun ... -- JSBillings 13:35, 18 July 2007 (UTC)

Actually, I suppose a comet or asteroid of sufficient mass could strike the earth at an oblique angle and send it spinning off in to space, so at one point it could have it's north pole facing away from the sun. It might even end up in a stable orbit, and have a tilt like Uranus.

And in that case, we won't be here to care :) Capuchin 14:06, 18 July 2007 (UTC)

(Edit conflict) Yes, but it probably won't be pretty for us on Earth when that happens. The comet would compress the Earth, and all the pent-up gas in the Earth's crust will be released, causing a huge blaze, and practically roasting everything on the Earth's surface. The shockwaves would also pretty much change the entire face of the planet. In fact, Earth might not even make it. And even if she did, it would take thousands to millions of years of years for the ecosystems on Earth to form again, and another million years for primapes to evolve into humans (or our equivalent). --Zacharycrimsonwolf 14:07, 18 July 2007 (UTC)

The Earth would not fall apart because of a mere comet. It would take something with much more mass to do that. Clarityfiend 17:15, 18 July 2007 (UTC)

Indeed - but a 'mere comet' couldn't flip the earth's axis to a noticable degree either (unless it was moving insanely fast!). But something big enough to change the earth's axis would certainly be enough to wipe out all life on the planet in the process. No - to address the OP's question: The answer is a categorical "No". SteveBaker 18:09, 18 July 2007 (UTC)

And any impactor with sufficent mass to significantly change the angular momentum of the earth would likely liquify the earth's surface in the process, making it an interesting fluid dynamics problem with no one around to solve it :) Unless of course, we can find a way to move to our similarly-created neighbor-RunningOnBrains 22:59, 18 July 2007 (UTC)

I think it's unfair to say the answer is "No". It is possible for it to happen, even if it kills every living thing on the planet, and in fact, it has happened to another, much larger planet in our own solar system. -- JSBillings 11:22, 19 July 2007 (UTC)

Actually, even if the south pole were aimed 100% accurately at the center of the sun - you still wouldn't get night over the entire northern hemisphere because (a) the sun is a lot bigger than the earth so it shines over more than half of the planet no matter how it's turned and (b) refraction through the atmosphere makes the sun appear higher in the sky than it really is - so even after the sun has mathematically 'set', it's still not dark - so you wouldn't get a full hemisphere of darkness - it would be a lot less. Still - if we're allowed to postulate catastrophies of earth-twisting proportions, let's just relocate the earth close to a neutron star and blow away all of the atmosphere - or maybe just move it so far from any star that it's "night" all the time, everywhere. Well - that's all well and good - but the "fair" answer is "No" - so let's not confuse the OP by saying otherwise. SteveBaker 21:37, 19 July 2007 (UTC)

Alternately, we could just redefine "Northern Hemisphere" to mean what "Eastern hemisphere" means now . . . Eran of Arcadia 17:21, 19 July 2007 (UTC)

How does that help? SteveBaker 21:37, 19 July 2007 (UTC)

Well, I don't reaslly have a reply, but I wanna ask, what does OP stand for? —Preceding unsigned comment added by Zachary crimsonwolf (talk • contribs) 11:37, 20 July 2007

See here. —Steve Summit (talk) 12:41, 20 July 2007 (UTC)

Is it possible...

...that the sun never sets on Russia? If their furthest west point is that little land-island that use to be Prussia (I think), and the furthest East is Diomede... has this been gone over before? 68.39.174.238 15:01, 18 July 2007 (UTC)

The sun never sets "on" any location on Earth. It is too far away to make physical contact. -- Kainaw^(what?) 15:12, 18 July 2007 (UTC)

Don't give stupid responses to straightforward questions.--138.29.51.251 15:14, 18 July 2007 (UTC)

It is not a stupid response. The question is not straightforward. A straightforward question would be "Is it possible that the sun is always visible from somewhere in Russia throughout the day?" Instead, the question is "It is possible that the sun never sets on Russia?" That question is vague. There are sunsets visible all over Russia every day. By simply using some intelligence in asking a question, it is easier to get an intelligent response. -- Kainaw^(what?) 15:46, 18 July 2007 (UTC)

Kainaw, the OP is no doubt referring to the concepts in The empire on which the sun never sets, or perhaps the British Empire, about which was said "the sun never sets on the British Empire". The idea is that a country and all its colonial possessions could encompass a sufficient number of widely-spaced territories on the Earth that the sun would always be above the horizon in at least one of them. Please don't assume that the OP is asking about the sun physically setting down on some piece of land—it's not polite to assume that degree of cluelessness without good cause. TenOfAllTrades(talk) 16:28, 18 July 2007 (UTC)

Thank you. 68.39.174.238 19:20, 18 July 2007 (UTC)

Our Russia article says the Russian Federation spans 11 time zones, which implies (roughly) that it covers not quite half of the span of longitudes, so clearly at some point (in the winter) the Sun is on the opposite side of the earth. You can see in this map that, even counting Kaliningrad, Russia does not span the more than the 180 degrees that would be necessary to have the sun never set.

I see... thanx. 68.39.174.238 19:22, 18 July 2007 (UTC)

You can play with [http:// www.daylightmap.com/ one of Google's toys] to see what is day vs night on a map. DMacks 15:53, 18 July 2007 (UTC)

Kainaw is perhaps not familiar with the old saying "The sun never sets on the British Empire," which was an observation of vast imperial geographic footprint, rather than a trivial astronomical fact. Edison 16:16, 18 July 2007 (UTC)

...which was also noted in can't-remember-what-humor-book with the explanation something like "this is because Britain is in the east, and the sun sets in the west". DMacks 16:54, 18 July 2007 (UTC)

Anguished English ? 68.39.174.238 19:22, 18 July 2007 (UTC)

Because the sun isn't a dot - it actually covers some angular extent, and refraction through the air means that that you can see the sun when it's technically below the horizon. According to Sunrise equation you get an extra 0.83 degrees at sunrise and sunset. Hence you don't quite need to cover 180 degrees of the earth's surface to get this result - but 178.4 degrees (OK - that's still not enough!). Also, our article on Antarctica says that Russia "reserves the right" to claim a part of that continent as it's terratory. Since it also owns parts of the earth very close to the north pole too - is it possible that between those two places that the sun never sets? It's a bit of a stretch though. The answer has to be "very nearly never sets". SteveBaker 18:06, 18 July 2007 (UTC)

Simply having Antarctic territory, without getting land somewhere in the 200° longitude not covered by Russia, would be insufficient. In the time frame around the equinoxes you can basically ignore the midnight sun effects of the polar regions, and you're left with the "not enough longitude" problem. For that matter, I don't think even some Antarctic land in the uncovered longitude is sufficient. My gut suggests that land sufficiently south (say, below 83°S or so) could still be under 24-hour night before the northernmost reaches of Russia (81°52') get 24-hour day. This, however, is a fairly fuzzy assertion. I'm quite confident that the problem would be simpler if we could talk territory outside the Antarctic Circle, and I'm pretty sure it would work out if Antarctic territory at the appropriate longitude were no further south than their antipodes were north. — Lomn 18:37, 18 July 2007 (UTC)

Further pedantry: 1) Kamchatka is both very easterly, and has a volcano 16,000 feet tall, so that might make the sun rise a bit earlier there. 2) According to this page, Russian modules on the International Space Station may be considered Russian territory for certain purposes, so that might affect the outcome, depending on its orbit (seems doubtful, though). Atmospheric lensing and the oblateness of the Earth should also not be ignored! --TotoBaggins 19:15, 18 July 2007 (UTC)

As a large portion of northern Russia is within the Arctic Circle, I thought of an interesting follow-up question: How long of a span during the summer does at least some part of Russia receive sunlight? Just a few days in June? Most of spring and summer? I don't have the right equations to do the calculations, just curious. -RunningOnBrains 22:51, 18 July 2007 (UTC)

Well, Extreme points of Russia says the northernmost point of Russian land is Cape Fligely. Plugging its coordinates into this web page along with various dates in 2007, I find... hmm, an anomaly. It shows sunrise and sunset on April 8, but neither sunrise nor sunset on April 9. Anyway, clearly the midnight sun starts about then. Then sunset will be on September 4, so that's about 149 days of daylight. --Anonymous, July 19, 2007, 03:18 (UTC).

Ah, this companion page shows sunrise at 20:22 UTC on April 8. I bet the other page just didn't look fr enough back into the preceding day. --Anon, July 19, 03:57 (UTC).

Stupid responses to legitimate questions such as Kainaw's are becoming increasingly more frequent in the RD. Perhaps we should warn about this somewhere. --Taraborn 17:22, 23 July 2007 (UTC)

Mould and Toxins

I'm writing a dissertation on coffee, and back when I started it I had access to a paper that said something along the lines of 'moulds undergoing temperature fluctuations produce more toxin than if they had been kept at a steady temperature' (specifically Ochratoxin A). Now that I have nearly finished, I find I cannot locate either the name or the address of this paper. While it appears to be common knowledge in the right areas that not only do fluctuating temperatures increase moisture levels, they stress mould into producing toxins, I cannot find a paper to use as a reference. Help!

I'm really hoping someone knows of, or can find, a decent thing I can use as a reference. I have access to a library, but I'm not subscribed to any places that offer papers. If it mentions it in the abstract (which I can view), that would be nice, or in a book, or anything that looks properly referencable. I'm having real trouble finding anything other than Geocities sites that actually mentions what I need to say I read D: Getting a bit desperate....

Thanks for any help. Skittle 16:04, 18 July 2007 (UTC)

• Production of Penicillic Acid and Ochratoxin A on Poultry Feed by Aspergillus ochraceus: Temperature and Moisture Requirements C. W. Bacon, J. G. Sweeney, J. D. Robbins and D. Burdick Appl Environ Microbiol. 1973 August; 26(2): 155-160
• Journal of Applied Microbiology Volume 97 Issue 2 Page 429-438, August 2004 Modelling the effect of temperature and water activity on growth of Aspergillus niger strains and applications for food spoilage moulds R. Parra and N. Magan

And many others.--Stone 16:42, 18 July 2007 (UTC)

And here's another:

"Under alternating temperatures OTA production was higher than at constant temperature, and alternating temperatures indirectly favoured OTA production due to condensation and a subsequent rapid increase in moisture content and water activity of the coffee beans." The production of ochratoxin A by Aspergillus ochraceus in raw coffee at different equilibrium relative humidity and under alternating temperatures (Palacios-Cabrera, et al. Food Control. Volume 15, Issue 7, October 2004, Pages 531-535) link

-- MarcoTolo 16:46, 18 July 2007 (UTC)

Thank you sooooo much! My saviours! :D Skittle 16:54, 18 July 2007 (UTC) In fact, I think Marco's one is the very one I initially had, right back at the beginning. Hooray! Skittle 17:00, 18 July 2007 (UTC)

greying eyes

I have dark brown eyes and they are actually changing to a greyish blue from the outter rim inwards and i am still young so I called my doctor and he told me that it was normal, then i was talking to my friend the other day and she said it's a loss of pigments and it happened to her brother (freaky!) so what exactly is the cause of losing pigments then?

There is discussion of this in Eye color. SteveBaker 16:55, 18 July 2007 (UTC)

Remove Scratches in Leather

Not sure if this belongs in Science Help Desk, but it's as good a bet as any. Does any one know how to get a fine scratch out of leather? It is a top quality leather sofa and the scratch is very fine (as if gently scraping your fingernail against the leather) -- yet noticable. The scratch is perhaps 1-2 inches long. Any suggestions on whether or not it can be "removed" or doctored up to be less visible? Thanks. (JosephASpadaro 20:05, 18 July 2007 (UTC))

http://www.google.co.uk/search?hl=en&q=leather+remove+scratch&meta= - apparently there are repair kits for these sort of small scratches commercially available. My first thought was a little shoe polish of a similar colour, but you might wish to try shop bought product first. Lanfear's Bane

Thanks. (JosephASpadaro 21:31, 19 July 2007 (UTC))

You might try something like an exact color match in a shoe polish (remember they use shoe polish for similar reasons other than just to make a shoe shine .. it covers over some of the scuffing scratches etc) afterwards try using a rag to get as much of the polish back off (leaving only a residual amount ideally in the scratch itself). Just a thought. TripleBatteryLife 15:59, 23 July 2007 (UTC)

Thanks for the ideas. (JosephASpadaro 05:13, 24 July 2007 (UTC))

Wholemeal v. wholegrain in the UK

Is there any difference between the two in the UK please? The article treats them as both the same, but I seem to rember reading about a difference at least in the UK. Thanks. 80.2.221.87 23:18, 18 July 2007 (UTC)

Wholemeal is meal (flour) made from whole grains of wheat, wholegrain is the whole grains of wheat etc. DuncanHill

How come you get wholegrain bread then? 80.2.192.45 11:02, 20 July 2007 (UTC)

Wholegrain bread has whole grains in it. DuncanHill 11:07, 20 July 2007 (UTC)

Harmone receptor question

What is Harmone receptor positive and Harmone receptive negative?72.76.142.100 23:37, 18 July 2007 (UTC)

I think you may mean Hormone receptor. There is some information in that article, but it is written in quite technical language. DuncanHill 23:41, 18 July 2007 (UTC)

I'm guessing you may be referring to how oncologists classify types of breast cancer. Patients with estrogen receptor (a type of hormone receptor) positive tumors will typically receive a hormone therapy treatment such as Tamoxifen. These treatments are ineffectual in hormone receptor negative tumors. Rockpocket 04:52, 19 July 2007 (UTC)

Parrot/Conure ID needed

I very nearly bought a parrot (poss. conure?) on a complete and utter whim today. This is a story that'll sound familiar to many pet owners - I saw it sat alone in a cage at the pet shop, looking very bored and it came up to me and let me stroke it when I tapped on the bars and made kissing noises. Very cute little bird - though I have no idea what species it was/is (never seen one like it before). Very, very tempted to take it home with me, though in the end I saw sense and decided to think it over.

It was a similar size to a cockatiel, though slightly 'wider', mostly olive green with some grey/brown on the head/neck and red feathers on the belly, a long darkish tail, black beak and white skin around the eyes and nostrils. It was completely silent the whole time I was there.

Anyone have any suggestions what kind of bird this is? The kid at the counter was only a part timer and she didn't know. --Kurt Shaped Box 23:45, 18 July 2007 (UTC)

Kurt, oh fellow bird lover. Don't do it! It sounds like a Sunday Conure, but there are several similar species. Parrots, especially Conures can be incredibly rewarding pets, but they take a great deal of commitment and time. After all they can live for 40-50 years or more! That said, go ahead and do some research and if you are ready to make the leap and are well prepared, then go for it! I highly recommend subscribing to the magazine Bird Talk (it is however, an American magazine and you may not be able to get it in Great Britian).--Eriastrum 00:24, 19 July 2007 (UTC)

I've owned/looked after a few different types of parrots before, so I do know what I'd be getting myself into - which at the moment is something I don't want to be doing. :) I have a few budgies at present (some in an aviary, one lone 'indoor budgie') - but they don't need a huge amount of one-to-one attention if you have several. Even the little guy seems to prefer to be left to his own devices (and his toys/beloved mirror!) most of the time. It's just so tempting when you see them in the shop, isn't it? I made that mistake once, with a lovebird when I was a kid - and the little thing ran me ragged for most of my teenage years (even though she was great)... --Kurt Shaped Box 01:07, 19 July 2007 (UTC)

July 19

Save energy by texting instead of eMailing?!?

Women’s Health magazine published a bunch of simple things we can do everyday to protect the environment (based on the new book, The Green Book: The Everyday Guide to Saving the Planet, One Simple Step at a Time). One of the tips is:

Text Him (or Her) Up

Instead of emailing to ask when he wants to meet at the restaurant, text him. It uses about 30 times less energy per message.

This seems like a pretty dubious claim to me - what do you guys think? SteveBaker 00:47, 19 July 2007 (UTC)

The sum total of saved energy would not be enough to remove the air from the brain of the person who thought this idea up.

Well technically, you probably are spending less energy to light the cellphone's screen than power a computer- but since your computer is probably on anyway, leaving it on while you use your cellphone spends more time and wastes energy on your cellphone. To be brutally honest though, that idea will save about as much energy as shaving your pencils with a swiss knife. --L^augh! 00:59, 19 July 2007 (UTC)

I think that the idea with that suggestion was that a cellphone has a small battery, while a computer is probably spending a lot of electricity to run. However, since your computer is probably already on, it's actually wasting energy. Bart133 ^{(t) (c)} 03:52, 19 July 2007 (UTC)

In my opinion, this is a gimmick by the service providers to get more people to start using text messages. They get paid for every text message (At least they do, in India). I have seen many such suggestions in general magazines, mainly because the writer of the article is not qualified enough to understand that what he / she reads / hears somewhere else may not be correct. The claim would be true only if one needs to power on the computer just to send a mail. But this fact is very obvious -- WikiCheng | Talk 06:54, 19 July 2007 (UTC)

Worthy of a Dilbert cartoon - almost as good as "smaller fonts take up less disk space". Gandalf61 10:33, 19 July 2007 (UTC)

Yeah, this is pretty stupid. Even though the computer uses more power, it most likely is on already. Also, you could probably type you message in and email it about 5x faster since you can generally type much faster on a keyboard then you can on a cellphone.--GTPoompt(talk) 20:24, 19 July 2007 (UTC)

(Saving Wikipedia disk space as instructed) That's pretty much what I've been thinking too - but then I wonder whether the cumulative load of trillions of emails has resulted in a ton of extra Internet infrastructure that could have been smaller/simpler otherwise - but then whether the cellphone network would be simpler if there were no text messaging. Seems like it's an incredibly difficult assessment to make - I can't imagine where you'd start gathering the data for such a claim. SteveBaker 21:04, 19 July 2007 (UTC)

And yet clearly someone did gather the data, because they didn't just claim that texting used less energy than email, they quantified it! I mean, that "30 times" figure has to mean something, right? --Steve Summit (talk) 21:44, 19 July 2007 (UTC) (Saving disk space on the confession that, yes, I'm being sarcastic.)

Oh - undoubtedly. If they'd said that emailing took 31.457 times more energy than texting then we'd know for sure that it was a totally bogus figure! "30 times" is right on the borderline of being oddly exact! SteveBaker 01:50, 20 July 2007 (UTC)

I think the consensus is that, while it's possible one method or another uses less energy, the amount of energy used to send an e-mail is so trivial we shouldn't be wasting our time thinking about it. If you print the e-mail out, however, then you probably use like 1000 times as much energy (in the manufacturing of the paper and ink, mostly). StuRat 02:51, 23 July 2007 (UTC)

It seems to me that most replies here equate "texting" with "emailing", which has never been my understanding; I've always used "texting" to mean SMS or other forms of phone-based texting, so the comments about a computer's power needs wouldn't seem to apply. Is this a regional terminology issue? jeffjon 20:50, 24 July 2007 (UTC)

The comparison is supposed to be between texting and e-mailing. I would take "texting" to mean "cell phone text messaging", too, although it could possibly also mean "instant messaging on computer". StuRat 06:12, 25 July 2007 (UTC)

Game without rules

It seems that every game has rules and that if something has rules that it is (or is treated as) a game. Are there any games that do not have rules and is there anything that has rules that is not a game? (Including any system such as law as being a rule and therefore the legal system a game.) 71.100.170.92 23:59, 18 July 2007 (UTC)

Calvinball --Trovatore 00:00, 19 July 2007 (UTC)

Unfortunately its only rule disqualifies it as being ruleless. 71.100.170.92 00:20, 19 July 2007 (UTC)

Actually - Calvinball does have one rule - you may never use the same rules twice. SteveBaker 00:46, 19 July 2007 (UTC)

Something that had no rules at whatever would not be an identifiable game - in as much as all games of that kind would (of necessity) be utterly identical. So: Here is a game called "Blank" which has no rules whatever:      -Let us know how much fun it is! There are lots of games with very few rules (eg Go), or rules that can be changed by the players (eg Nomic) - or where rules change as a part of how the game is played (eg Lemma [2])- or which have rules you make up as you go along (eg Calvinball)- or which simply don't exist at all (eg Mornington Crescent (game)). Here is a game I played with friends in college: Take a chess set - set it up the usual way - but make the rule that no piece is allowed to move at all. Each turn, you may either redefine how a type of piece moves (eg pawns can only move if they start on a black square and they do so by moving three spaces diagonally in any direction) or you can move a piece according to whatever set of rules exists. If you lose your king, you lose - and if you are 'in check', you can't redefine the movement pattern of any of the pieces that have you in check. SteveBaker 00:35, 19 July 2007 (UTC)

Mao (game) has rules that are kept secret from new players. List of games with unspecified rules is of relevence. SteveBaker 01:06, 19 July 2007 (UTC)

And the second part of the question - things with rules that are not a game are everywhere. Our legal system - computer programming - electronics design - life itself! SteveBaker 00:39, 19 July 2007 (UTC)

Steve, please read WP:NPOV --L^augh! 00:57, 19 July 2007 (UTC)

Sorry, this is Wikipedia - we make up the rules as we go along. SteveBaker 01:06, 19 July 2007 (UTC)

Would you like to play the game of questions from Rosencrantz & Guildenstern are Dead? --Trovatore 01:18, 19 July 2007 (UTC)

"Oh! You mean....you pretend to be him, and I ask you questions!" -- MarcoTolo 02:07, 19 July 2007 (UTC)

Statement. One-love. Whose serve? --Trovatore 02:08, 19 July 2007 (UTC)

Since this is science desk, Science and Mathematics in particular have rules that are not a game. --Tbeatty 04:32, 19 July 2007 (UTC)

Well, anyone could always consider it a game if they chose, although I'm still waiting for a physicist to shout "PWNED" while receiving a Nobel Prize. Someguy1221 04:46, 19 July 2007 (UTC)

zOMG LAG. Capuchin 06:40, 19 July 2007 (UTC)

Yes, I would say so. After all, game theory, the mathematics to reason about strategy in games, is not used to reason about children's games but about real live, and a key point is that rules may emerge because it would be disadvantegeous not to follow them. Capitalism in its most extreme form is a game without rules. International politics may be an even better example: as there is no world police, there is no way to enforce compliance with international treaties -- except for the fact that you may be punished by other players for cheating one player. These other players enforce the rules not because they are rules but because the enforcement is a game move of advantage. (See altruistic punishment.) A very extreme example is the classic application of game theory: nuclear strategy. There are no rules in nuclear warfare, just the goal to get not too many of your own people killed. ("Mr. President, I'm not saying we wouldn't get our hair mussed. But I do say no more than ten to twenty million killed, tops. Uh, depending on the breaks." --General Turgidson in Dr. Strangelove). And, finally, the largest game ever, with no rules at all: Evolution. Pity that our article on Evolutionary game theory is just a stub. Simon A. 08:53, 19 July 2007 (UTC)

My understanding of evolution is that it most certainly does have rules. Anyways, it seems that anything people are involved in that is competitive, which often seems like damn near everything, will be understood or framed by some as a "game" regardless if it has any clearly defined rules or how serious it might appear to be (ex. "The Great Game"). In some games winning is all that counts; Love and War are often seen as games and if it's true that "all is fair" in them, then I suppose they have no rules. -- Azi Like a Fox 12:14, 19 July 2007 (UTC)

The laws of physics (biology/chemistry/math/whatever) are a set of 'default' rules that are inherent in every game we play. If we count them as "rules" in the context of this question then there can be no games that have no rules because the laws of nature are irrefutable and immutable. If we say "No - those aren't really 'rules' in this context" - then evolution has no rules. I just basically dislike equating an arbitary 'process' with a 'game' and laws of nature as 'rules'. Rules should be arbitary things that humans have imposed in order to restrict arbitary behavior to some subset that we call 'the game'.

Actually - it's not just humans. My dog has a clear set of rules for the 'pull rope and fetch' game.

1. Human and dog grab opposite ends of the rope - nobody pulls until everyone has a good grip.
2. If dog pulls rope from humans hand then dog holds the rope 6 inches from human hands - and moves it just out of reach if human tries to grab it - until human succeeds in grabbing it.
3. If human pulls rope from dog then human throws rope far away and dog has to run and bring it back at which point human grabs it or (optionally) dog may choose to invoke rule 2.
4. Game is over when either party drops rope without a fight.
5. (and this is the rule I'm least clear on) Scoring has something to do with the amount of growling involved - if you can employ ventriloquism in order to bark without causing rule 3 to be invoked, that's extra points?!?

But these are a clear set of rules - that were not thought up by a human. SteveBaker 19:59, 19 July 2007 (UTC)

TEGWAR. Corvus cornix 17:41, 19 July 2007 (UTC)

Many games in the List_of_fictional_games don't have any rules. Do they count?

Basis of distinction

In reference to SteveBaker POV (as in Perspective (cognitive), which is highly valuable, relevant to the question and sought after here within the context of this discussion) How does one distinguish (i.e., what rule might one use to distinguish) between something that has rules and is a game and something that has rules and is not a game? Julie Dancer 08:46, 19 July 2007 (UTC)

A game is an event which has a goal and/or a winner. Even our academics (passing from one grade to another) can be viewed as a game. Bidding for a project can also be viewed as a game. Planning and executing a theft is a game too :-) -- WikiCheng | Talk 12:20, 19 July 2007 (UTC)

In that context then, in absence of a rule to make the distinction, is there anything which has rules that can not be played as a game? Julie Dancer 12:33, 19 July 2007 (UTC)

I would say no, there would be nothing preventing someone from playing whatever as a game given cheng's definition. Can think of things that should not be played as a game and also things that in most cases would not be (for example anything involving going to the DMV- there might be rules to follow and a goal, but you would have to be fairly masochistic to view the experience as a game). 38.112.225.84 12:56, 19 July 2007 (UTC)

Yes, but what about a rule that makes such a distinction? Julie Dancer 14:49, 19 July 2007 (UTC)

It's really all in the mind. Take the classic Prisoners Dilemma "game". If you are an actual prisoner facing a life or death situation - then this is a situation with arbitary rules that is most definitely not a game! If you are a mathematician studying the prisoners' dilemma as a part of game theory - then (ironically), it's still not a game. If you play Prisoners Dilemma with a good friend in a pub over a couple of beers - then it's a game. The group who were testing the theory of altruism using an iterated version of the prisoners dilemma were doing serious research (using 'tit-for-tat' strategies within it) - but the people they asked to contribute computer programs to play it were treating it as a game - in that case, this thing was simultaneously a game and not a game. This is true of many things. Just think of the number of competitions there are for things like good cooking skills - which is a game when they say it's a game - and a chore to do if you don't feel like being the one whose turn it is to cook tonight. SteveBaker 19:43, 19 July 2007 (UTC)

So are you saying that the distinction is that in the presence of rules something is a game if you choose to play (or participate as a player) and not a game if you choose not to play (or to participate as a player)? If so then what about those situations where you are required to participate whether you like it of not in order to exist or to not be terminated? Is this the rule that you would use to determine whether or not the presence of rules did or did not entail the presence of a game?

For instance. Suppose I am a bus driver and I am told (given a rule) that if I see a knife or a gun then the passenger can not come on board or if on board must be told to leave but if same passenger hides the gun or knife so that it can not be seen by me then the passenger can come on board or remain on board unless I have already seen the knife or gun then the passenger must leave.

To me these rules amount to playing the game of deceiving the driver as official policy of the bus line and I choose to decline to play this game. If I decline then I cannot be a bus driver. I either play this game or I loose my job. Julie Dancer 21:05, 19 July 2007 (UTC)

No - not at all. I'm saying it's a game if you treat it as such - no more, no less. If winning isn't all that critical to you - then maybe it's a game. If playing it is life-and-death or losing your job or whatever - then it's not a game anymore - even though the rules are the same and the players are the same. To quote the Wiktionary: Game - A pursuit or activity with rules performed either alone or with others, for the purpose of entertainment. - that last bit says it all 'for the purpose of entertainment' - as soon as it's not entertainment anymore - it's no longer a game. Those same set of arbitary rules (which evidently aren't a game to the bus driver) might make perfectly good rules for children playing "bus driver and urban terrorist" in the schoolyard. My point is that it's not what the rules are that make it a game or not - it's purely the context in which those rules are being obeyed and the mindset of the participants.

This may not be entertainment for the driver but what about for the administration? If the administration finds it entertaining then it would seem to still be a game.

Take the Roman Colosseum. For whom was the death at the mercy of the Gladiator or the wild beast a game whereas for the Emperor, no doubt it was all merely entertainment.

In our own legal system, many including prosecutors, judges, clerks and defense attorneys in addition to the accused him or her self may see the entire process as a game to be played at someone else's expense. Nonetheless I agree that entertainment is probably the best rule for determining whether or not something that has rules is or is not a game. Julie Dancer 08:08, 20 July 2007 (UTC)

Is One Button a game? Nimur 06:58, 20 July 2007 (UTC)

And if it is, when does the game begin? According to some, everybody is already playing One Button, they just haven't won it yet. Nimur 07:00, 20 July 2007 (UTC)

To me, it seems that Julie and Steve use the word "game" in pretty much opposite meanings. Steve uses the everyday definition of "game", namely something that you do for fun. Julie uses the definition from game theory: everything where a set of rules is either set explicitely or can be abstracted from the circumstances that detemine who is wins and who loses. To me, the game theorists have a point, albeit one for a slightly cynical realist: A gambler plays a game, and a daytrader seems to do the same, and it's clearly not just for fun. Looking at maps and military strategy plans one can't help noticing that from generals' point of view, war looks like a game. And that it, in fact, is one is the great tragedy of all history. Simon A. 14:46, 20 July 2007 (UTC)

Then are you saying that the rule which distinguishes a set of rules as being or not being a game is the consequence of playing the game for the individual player or for the follower of the rules? Julie Dancer 16:40, 20 July 2007 (UTC)

Re:Magnets

I know that magnets' opposite poles attract each other (north attracts south), but why does a magnet's north pole points to the Earth's North pole? Shouldn't it be going the other way instead? --Zacharycrimsonwolf 12:16, 19 July 2007 (UTC)

Well, we call the pole towards which a magnet's north pole points as the north pole. As you mentioned, it is the earth's south (magnetic) pole which attracts the magnet's north pole. To put it in simple words, if you imagine earth to be a big magnet, the south pole of the earth magnet is near the geographic north pole and vice versa. See Magnetic_North_Pole. It states that 'the Earth's North Magnetic Pole is therefore physically a magnetic south pole' -- WikiCheng | Talk 12:30, 19 July 2007 (UTC)

The choice of the magnet's names of the poles comes from the direction they point when used as a compass. They were named before people realized that the earth acts as a giant magnet. -- JSBillings 12:57, 19 July 2007 (UTC)

Okay. That would mean the Earth's south magnetic pole is named the North Pole? Thanks. Cheers, Zacharycrimsonwolf 11:32, 20 July 2007 (UTC)

Yes, how they are named and how they actually behave are polar opposites. StuRat 02:42, 23 July 2007 (UTC)

project

can someone explain to me where to search for the abstract and implementation of any electrical project? i need to do an electrical project for my final year in college and i have already searched countless webpages in vain. i did not find a suitable project. can someone say where to search for a good electrical project (projects as advanced as the projects one can find in IEEE magazines). —Preceding unsigned comment added by 59.89.20.202 (talk • contribs)

Why not take one of those existing projects and add a clock to it? :) Or do some other novel adaptation that contributes something to the field, and catches your interest? MAKE magazine frequently has spiffy electrical projects, but they may be too simple for what you're looking for, but perhaps you'll find some inspiration there. --TotoBaggins 17:01, 19 July 2007 (UTC)

Solar powered garden light that turns on when it hears footsteps instead of turning on only when it is dark.Polypipe Wrangler 01:48, 20 July 2007 (UTC)

To expand on that last idea, also consider the use of passive infrared sensors rather than acoustic detection.

Atlant 12:03, 20 July 2007 (UTC)

You're probably looking for websites called "Electronic Circuits Archive" or "Schematic Archives." Here's a few:

the electric wave

web-EE archive

U. of Washington circuit archive

delabs

electronics-lab.com

circuit exchange int'l

Free Electronic Circuits

DMOZ links to more archives

And here's my links to some particularly fascinating examples

Causes of losing a wheel

I'm interested in knowing more about the technical aspects of the holding capacity of lug nuts on Wheel studs.

I've found a fascinating article at [3] explaining how bolts work, but I have two questions which I hope someone could answer in terms which are not too technical.

1. Apart from not being adequately tightened, what other factors, or conditions, might cause a nut on a car's wheels to loosen and eventually come off?
2. If a wheel stud does not completely penetrate and pass through to the other side of an open lug nut, will this reduce the holding force of the nut, and, if so, how might one calculate the reduction of holding power related to the depth of penetration of the stud? --JAXHERE | ^Talk 17:05, 19 July 2007 (UTC)

Lots of things can reduce the grip of the nut on the bolt:

• If you somehow got oil or grease onto the threads - that would do it.
• If they are over or under-tightened.
• If they were overtightened sometime in the past.
• If a nut with the wrong kind of thread were put onto the bolt - either now or in the past or if it somehow became cross-threaded either now or in the past (this was the case when I took delivery of my 1963 Mini which had seven cross-threaded wheel nuts on it - three of which were on one wheel!!).
• Some old/large vehicles have threads that tighten up in the anticlockwise direction on one side of the vehicle to allow for the fact that the direction of rotation of the wheel can cause wheel nuts to loosen - so I suppose the nuts on that side of a 'normal' car would be more prone to this than those on the opposite side.
• I suppose that if you've swapped wheels an insane number of times then the threads might start to wear out...seems unlikely though.
• Corrosion of the threads is a problem because the rust doesn't have the strength of the metal - and even if the rust has been removed, the resulting loss of metal will reduce the quality of the contact between nut-thread and bolt-thread.
• Certainly if the entire depth of the nut is not fully threaded onto the bolt. The actual math of a nut that's only partially threaded onto the bolt is going to be complicated. It's tempting to say that if the bolt only goes X% of the way through the nut then the nut must have only X% of the usual 'holding power' - but the thing about wheel nuts is the damage that happens to the threads on the bolt. When you over-tighten them (for example), you can actually distort the metal of the threads on the bolt so that the nut doesn't grip as well. Even after you correct the tension on the fitting - that distortion remains - weakening the grip of the nut on the bolt forever more after that. Similarly (I suppose), having the nut correctly torqued up - but with only half of the thread engaged is putting double the usual force on every centimeter of the thread - and that's like you over-torqued it. So you might find that you damage the bolt so the holding force of the nut is halved because there is half as much thread providing the necessary friction - but ALSO, you now have a damaged or weakened thread on the half that is engaged - so that could easily reduce the amount of grip even further.
• You can use a commercial 'thread lock' compound ("Loctite" is the most popular brand) to improve the adhesion of nut to bolt.

Bottom line is whichever of those things you think you screwed up: "Don't Do That!" ...and if you did, consider getting a new set of wheel bolts. The ones I bought for my Mini only cost a couple of bucks each and they were pretty easy to replace. I would also recommend buying a torque wrench and tossing that into the toolkit in the back of your car so you can get the tension right even if you are putting on a spare tyre at the side of the road. SteveBaker 19:27, 19 July 2007 (UTC)

I'll bet more wheels fall off as a result of wheel bearing failure than lug nut failure. That is, someone botches the assembly of the wheel bearing, its castellated nut, the cotter pin, or what-have-you and the bearing falls apart on the road. Or the bearing freezes as a result of faulty lubrication and overheats, eventually causing something mechanical (like the stub axle) to break.

Atlant 12:10, 20 July 2007 (UTC)

Supporting principles

• Thanks for the responses, everything seems to make sense, to me. Now the really tough part: Can you direct me to on-line authorative explanations of these concepts? The link I gave at the beginning is a part, but I'd hope I can find more, but the searches I've done so far hasn't uncovered enough. --JAXHERE | ^Talk 15:07, 20 July 2007 (UTC)

• Our impact force and impact wrench articles discuss some of the physics involved in tightening bolts. StuRat 02:25, 23 July 2007 (UTC)

Reusing Nomenclature

Okay, so I know that if any given organism (living or extinct) is given two names, then the one published first is used; but what happens to the old name? In other words, if we discover the direct ancestor of Hyracotherium, can it be called Eohippus? If they definitely identify the oldest ancestor of humans that is not an ancestor of chimpanzees (assuming we haven't already) can it be called Eoanthropus? These are just examples; I guess they could call an insect Eohippus as well. Eran of Arcadia 19:30, 19 July 2007 (UTC)

I don't know about previously used names, but there are examples where the same name appears in two widely seperated family trees, i.e. there might exist a Sillius group of rodents and a Sillius group of insects. As long as they are sufficiently distinct organisms there is little chance of confusion. Often this occurs when the name itself is not very inventive, such as naming a group after the country in which they were first found. Sorry, I don't recall any specific examples. Dragons flight 01:58, 20 July 2007 (UTC)

What do you mean by "group" in that case? Can a genus name appear twice, or only higher levels? Eran of Arcadia 02:51, 20 July 2007 (UTC)

I don't have the time to go slogging through the primary source material at the moment, but Nomenclature Codes has links to the widely-accepted codes governing the naming of organisms. There are separate codes for animals (ICZN), plants and fungi (ICBN), and bacteria (ICNB). I would expect (or at least hope) that the Codes would contain the rules on re-use of names. TenOfAllTrades(talk) 02:46, 20 July 2007 (UTC)

Strictly speaking, only specific names may be shared among several species (in different genera), but all other ranks must be unique. There are so many rules that some violations are overlooked if they're benign, simply because scientist have better things to do. The Vianna code is coming online soon. I suspect old invalid names may be reused, but only with fairly unrelated organisms to avoid confusion. Bendž|Ť 21:05, 20 July 2007 (UTC)

That's a shame then, Eohippus is too cool of a name not to get a horse named with it . . . Eran of Arcadia 01:08, 23 July 2007 (UTC)

Need help with particle reactions

can anyone give me the net energy changes, or a method of working them out, and also the required conditions for the following events.

1. ${\nu }_{e}+{\hbox{n}}\to e^{-}+{\hbox{p}}$
2. ${\bar {\nu }}_{e}+{\hbox{p}}\to e^{+}+{\hbox{n}}$
3. ${\hbox{n}}\to {\bar {\nu }}_{e}+e^{-}+{\hbox{p}}$

Cheers. Philc 19:36, 19 July 2007 (UTC)

You can get an idea by using E=mc², along with the mass of the neutron, proton, and electron. Your neutrino or antineutrino are approximately massless, though that is a hypothesis. The positron is the same mass as the electron. Your last reaction is the spontaneous decay of the neutron. GB 21:21, 19 July 2007 (UTC)

That only takes into account the mass changes, I want to also consider the kinetic energy of the particles on either side of events. Because also I don't know how much energy is required to initiate the reactions, and how much is released as KE. Philc 23:29, 19 July 2007 (UTC)

To Graeme, I don't think ignoring the neutrino mass is a hypothesis, it's more of an approximation (a very good one). As for knowing the KE of all the particles, that is tricky. The neutrino is not repelled in anyway, so there's not really a 'coulomb barrier' style activation energy. The neutrino I think can have any energy. Certainly in the three body decay (the third equation), you cannot tell how the energies will split. This was in fact some of the early evidence for a neutrino, had the neutron simply gone to e and p their energies would have been well defined, but the existence of the neutrino means they aren't. Sorry if that's not so helpful. Cyta 07:47, 20 July 2007 (UTC)

Number 3 is the spontaneous decay of a neutron - no initial kinetic energy is required, but all the mass difference goes into the kinetic energy or the products. You can work this out. For part 1 of the homework this is the neutron decay accelerated by neutrinos. The crosssection will be very low, but it may vary with the energy of the neutrino. Number 2 is your inverse neutron decay, you will have to supply enough energy to create the extra mass. You cna't know the kinetic energy of all the particles as Cyta says, instead tehre is a range of possible values as the energy is split between particles. see beta decay. I was saying that the idea the the neutrino is massless is a hypothesis. GB 07:57, 20 July 2007 (UTC)

I thought that with the observation of neutrino oscillation, the idea that the neutrino is massless is simply wrong? Algebraist 10:49, 20 July 2007 (UTC)

It's a shame you had to imply this is homework. It's Late July, I don't know of any schools that aren't on holidays, and I certainly am, I was purely wondering out of interest in a larger picture, I can explain to you if you want. I was looking at the possibility (purely playing with ideas in my head) of using the ${\bar {\nu }}_{e}$ and fast ${\hbox{n}}$ generated during nuclear fission. Using the equations I listed:

1. ${\nu }_{e}+{\hbox{n}}\to e^{-}+{\hbox{p}}$
2. ${\bar {\nu }}_{e}+{\hbox{p}}\to e^{+}+{\hbox{n}}$
3. ${\hbox{n}}\to {\bar {\nu }}_{e}+e^{-}+{\hbox{p}}$

by adding (1) and (2) you get;

${\bar {\nu }}_{e}+{\nu }_{e}+{\hbox{n}}\to e^{-}+e^{+}+{\hbox{n}}$

if you add this to (3) you get;

${\bar {\nu }}_{e}+{\nu }_{e}+{\hbox{n}}\to e^{-}+e^{+}+{\bar {\nu }}_{e}+e^{-}+{\hbox{p}}$

${\bar {\nu }}_{e}+{\nu }_{e}+{\hbox{n}}\to 2e^{-}+e^{+}+{\bar {\nu }}_{e}+{\hbox{p}}$

if you add this to (2) you get

${\bar {\nu }}_{e}+{\nu }_{e}+{\hbox{n}}\to 2e^{-}+2e^{+}+{\hbox{n}}$

The electron and positron could then be tapped off using magnetic fields as they would move in opposite directions, therefore preventing instant annihilation.

What I was basically wondering is how much kinetic energy this chain of events would require to initiate, and pass through to the end, and how comparable that would be with the KE of ${\bar {\nu }}_{e}$ and fast ${\hbox{n}}$ from fission, and the billions of ${\nu }_{e}\,$ flying in from the sun every second. Philc 11:25, 20 July 2007 (UTC)

Sorry about upsetting you with the homework suggestion. The minimum egergy required will be that required to form the two electrons and two antielectrons, which I think is 4*511keV or 2.022 MeV. However the reaction you describe would have an incredibly low cross-section. It is hard enough for one neutrino to hit a neutron, let alone two at the same time. You can see how slowly the detectors find neutrinos from the sun to get an idea of the low chance that a reaction occurs. Extrememly high energy neutrinos with energies in the EeV range have a much bigger chance of impacting matter. GB 11:59, 20 July 2007 (UTC)

Because of the nature of the reaction stages as opposed to all at once, it wouldn't require the neutrinos to impact simultaneously, but point taken on the non-likelihood of the reaction taking place. Do you have any idea where I can find out the kinetic energy of neutrons and antineutrinos from nuclear fission. I was assuming it was quite high, given that they are known as fast neutrons, and have to be mediated with boron. But since they were called fast neutrons simply to differentiate from slow neutrons, purely in the context of propagating fission reactions, I can't really assume that it is comparable to the energies required for particle reactions. Philc 13:25, 20 July 2007 (UTC)

In Nuclear chain reaction you can see U-235 + neutron -> fission fragments + 2.52 neutrons + 180 MeV. The energy is split between the different four to five particles, so there could easily be several MeV per neutron, so fast neutron would have the energy necessary. Neutrinos from the sun[4] seem to have a relatively low energy, below half a MeV, so they would not contrubute much to the reaction. GB 01:44, 23 July 2007 (UTC)

Ok, thank you very much. Philc 15:02, 24 July 2007 (UTC)

Electronics: Can something that requires 100mA run off of 500mA?

Hello, I play guitar and in the world of electric guitar there are foot pedals that you can switch on and off to use a desired effect, and I prefer powering them with an adapter. In this case, my Electro-Harmonix Small Clone chorus pedal says it requires 100mA of current. I went to 3 separate stores and they didn't have the exact adapter that the company would like you to have, but one store did have an Electro-Harmonix adapter that provides 500mA instead of the required 100. My question is, is this going to fry my pedal? Or does the pedal limit the current draw? I'm pretty sure it is limited and should be fine, but I don't want to take a chance cause this pedal was almost $90. Thanks! NIRVANA2764 20:34, 19 July 2007 (UTC)

It's no problem - the pedal will only pull the amount of current it needs. You need to be sure that:

• The voltage is set correctly for the pedal.
• That the power socket has the correct tip/ring polarity. There is usually a picture on the pedal that shows which is positive - most 'generic' power supplies have a way to get the wrong!
• That you have ENOUGH amps avaliable on the power supply (which you do!)
• If you plug it all in and it doesn't immediately work - unplug it REALLY QUICKLY and double check everything - with any luck you'll avoid damaging it.

Personally, I wouldn't buy an adaptor for another pedal - I'd go to WalMart or RadioShack (or whatever your local equivalent is) and buy one of those switchable power supplies that comes with a bazillion different connectors and can be switched to any voltage. Those are cheaper - have a range of connectors and are generally more flexible in terms of tip/ring polarity. My son has several effects pedals - and they all run off of these switchable power supplies. SteveBaker 20:53, 19 July 2007 (UTC)

Thanks a lot for your help. A lot of people are recommending universal adapters to me, and it seems like a good idea (they are cheaper than regular ones...don't know why though) but I have fried 2 of them to date, and I don't know why. Perhaps my pedal required more current than the pedal could supply. I would use them fine for a few months, then one morning, find them to be not providing any current to my pedal. The sticker on them would be warped, leading me to believe that they got overheated and just died out. I've asked many people and nobody can explain it. So now my philosophy is that I will buy only the adapter that the manufacturer suggests, because I'm tired of frying adapters. NIRVANA2764 20:58, 19 July 2007 (UTC)

Certainly you need to ensure that the adaptor can provide the current the pedal demands - and with some of them you have to read the fine-print on the packaging because some of them can deliver less amperage at higher voltages. Ideally, you want the adaptor to be able to produce roughly twice the amperage of the device it's driving in order that it should run fairly cool. If the adaptor is putting out close to it's maximum then it'll get hot and probably, it's lifetime will be shorter too. My son uses four 'COBY' 500mA supplies to drive four guitar effects pedals from various different manufacturers - and so far, none of them have died over more than a year of fairly frequent use. I'm running my laptop from a universal adaptor too - but it's running fairly close to its' maximum capacity for over a month now. It's hot and the label has warped and fallen off...so I don't expect it to last for very long. But the original supply for my laptop died and HP wanted $80 for a replacement. The no-name variable supply cost $20 - so I figure I'll still be ahead of the game when I'm on my fourth one! But buy universal adaptors with plenty of spare capacity for the pedal you have and they'll run cooler and last MUCH longer. SteveBaker 01:32, 20 July 2007 (UTC)

Questions about voltage and current are surprisingly frequent here on the Reference Desks. Here is a handy way to think about and remember the difference. It is traditional to use fluids in these analogies.

Suppose you have a recipe for Cherries jubilee that calls for one cup of 80 proof Kirschwasser. Suppose you are low on funds (and have a tin tongue to boot) and you try to use Budweiser instead of Kirschwasser. But when you try to ignite the flambé, it ain't gonna burn, because beer just doesn't contain a high enough concentration of alcohol for that.

Suppose that, stung by this demoralizing failure, you resolve to save your pennies until you have enough to head down to your friendly neighborhood liquor store to buy some of the real stuff. But they won't sell you a cup of it -- the smallest bottle of Kirschwasser they have is 500 ml, or a little over 2 cups. The burning question is: will the 500 ml bottle do? And the answer is, of course it will (assuming you can afford it). You can almost certainly find something to do with the extra 1.113 cups of liqueur when you're done with (or perhaps even as you're enjoying) that dessert.

Amps are like cups. Volts are like proof. It doesn't matter if your supply has too many cups; it only matters if it has too few, or if the proof is too low, or too high. Prost! —Steve Summit (toast) 02:38, 20 July 2007 (UTC)

[P.S. Stay tuned for our next exciting episode, in which we learn that watts are like hangovers.]

Wot?

Atlant 12:20, 20 July 2007 (UTC)

Another comparison: Watts are like beer, while Volt-amperes reactive are like the foam on the beer. Edison 20:55, 20 July 2007 (UTC)

I'm going to make a platinum plated spork - I mean that! SteveBaker 01:12, 21 July 2007 (UTC)

Now, now, it was a reasonable (if obscure) analogy: just as reactive current takes up capacity in your transmission lines without transmitting any useful power, so does the head take up space in your glass without providing any useful beer! —Steve Summit (talk) 01:33, 21 July 2007 (UTC)

What is the difference between sociopath and psychopath?

Right now, sociopath redirects to psychopath, and the psychopath article says that they are the same thing, just different terms. But the sociopath page has sort of an edit war with some users redirecting it to antisocial personality disorder and others changing back to psychopath. Which is correct?--64.149.176.55 21:25, 19 July 2007 (UTC)

Yes, those editors are demonstrating an approximately correct usage of the terms, sounds like. --Steve Summit (talk) 22:36, 19 July 2007 (UTC)

If memory serves, psychopath is an antiquated term, which has been replaced with sociopath. They might have slightly different shades of meaning, but I think that that's the gist of it. Raul654 21:30, 19 July 2007 (UTC)

"Psychopath" and "sociopath" are terms used in common parlance but the APA would say that these refer to persons with antisocial personality disorder (cf DSM IV). Donald Hosek 22:13, 19 July 2007 (UTC)

I think both Raul & Donald above are on the right lines, it might also be useful to compare dictionary definitions, these from Chambers Dictionary 1983 edition. " Psychopath - one who shows a pathological degree of specific emotional instability without specific mental disorder: one suffering from a behavioural disorder resulting in inability to form personal relationships and in indifference to or ignorance of his obligations to society, often manifested by anti-social behaviour, as acts of violence, sexual perversion, etc." " Sociopath - sociopathy - any of several personality disorders, resulting in asocial or antisocial behaviour. " DuncanHill 22:38, 19 July 2007 (UTC)

For what it's worth, DSM IV doesn't use either term, as Donald says, it does have antisocial personality disorder. DuncanHill 22:48, 19 July 2007 (UTC)

David T. Lykken illustrated the difference with the classic nature and nurture division: psychopathy is a psychological condition caused by natural conditions such as brain damage or atypical neural development, while sociopathy is a sociological condition caused by nurtural (is that a word?) conditions childhood abuse, poverty, extremely high/low intelligence (although of course most people would have a combination of the two, brought about by a combination of nature and nurture). Laïka 00:13, 20 July 2007 (UTC)

Relativity

Suppose there are two beams of light alongside each other, Beam A and Beam B. According to the special theory of relativity, the speed of light is the same from any ppoint of reference. Would Beam B be traveling at the speed of light from Beam A's point of reference? ¿SFGiДnts! ^{¿Complain! ¿Analyze! ¿Review!} 21:35, 19 July 2007 (UTC)

By talking about "beams of light", do you really mean, "the point of view of a photon inside a beam of light"? As it is you make it sound like you think of the beams as static entities, but they aren't. But in any case — yes, assuming they could be observers in a traditional sense, from their frames of reference they will measure one another as going the speed of light (assuming they are both in a vacuum). --24.147.86.187 22:47, 19 July 2007 (UTC)

Short answer, yes. Long answer, the question is ill-posed. Time would appear to stand still for a hypothetical observer moving at the speed of light and hence he would be unable to measure the speed of the second beam of light. So, technically it is not possible for any measurements to be made from the point of view of a beam of light. However for reference frames arbitrarily close to the speed of light you can still make the measurement and you will always find that light moves at light speed.  ;-) Dragons flight 22:55, 19 July 2007 (UTC)

(edit conflict x2) Things get funny in special relativity if you pick a lightlike reference frame, since you end up with infinite time dilation. Essentially, for an observer moving at the speed of light, no time passes, and so questions like "how fast is something else moving relative to me?" become rather meaningless. —Ilmari Karonen (talk) 22:55, 19 July 2007 (UTC)

The main problem with the question is the misunderstanding of the special theory of relativity. The question uses the phrase "from any point of reference". That is not what the special theory of relativity states. It only applies to inertial frames of reference. A photon traveling at the speed of light is not an inertial frame. As the article the OP linked states: "Relativity theory depends on "reference frames". A reference frame is an observational perspective in space at rest, or in uniform motion, from which a position can be measured along 3 spatial axes. In addition, a reference frame has the ability to determine measurements of the time of events using a 'clock' (any reference device with uniform periodicity)." It is hard for a photon to measure time when time is standing still. -- Kainaw^(what?) 23:06, 19 July 2007 (UTC)

I knew I should have paid better attention in middles school science. :) ¿SFGiДnts! ^{¿Complain! ¿Analyze! ¿Review!} 00:09, 20 July 2007 (UTC)

IMAGINE you are a photon in a long line of photons moving in the same direction (all moving of course at the speed of light relative to someone not moving). Wouldn't the photon in front have to be moving at your same speed, and the one behind also moving at your same speed? So to each of you in the line there is no motion relative to each other. Isn't it the same for a photon out to the sides moving in your same direction? SO.. if you are motionless in your own frame of reference, an outside observer would appear to be moving in reverse at light speed right? According to relativity the outside observer would experience time standing still since he is going at light speed relative to you. But your world is motionless and time for you is normal? Confusing isn't it.

No it is not. This comes up on a weekly basis here. What it boils down to is this concept of "motion" and "speed". If you stop using those broken concepts it makes perfect sense. The one with the highest energy-to-mass ratio is "traveling faster". If it is 100% energy, it is "traveling at the speed of light". So, two photons are hopping along at the "speed of light" - which means they are 100% energy. They go in opposite directions, or the same direction, or in random circles and swirls. Does the fact that they are both 100% energy change? No. What if some guy is sitting at his computer trying to make this confusing? He is only about 10% energy. Does the movement of the photons change the fact that is he only about 10% energy? No. But he is relatively moving away from the photons? Big deal - he's still only about 10% energy. But I've always been given an example of a spaceship traveling through space! So - it was a bad example. He's still only 10% energy. But that isn't in the Wikipedia article! So - he's still only 10% energy. But I've read the Cryptonomicon! So - you have a high tolerance for bad prose. He's still only 10% energy. Regardless of your argument, it isn't confusing. -- Kainaw^(what?) 12:08, 25 July 2007 (UTC)

July 20

Tabby Markings in Lions

Why do lion cubs (possibly also adult lions) have the "M" tabby marking on their forehead, just as house cats do? See http://www.dailymail.co.uk/pages/live/articles/news/worldnews.html?in_article_id=469379&in_page_id=1811, see images 5 and 7. - MSTCrow 03:16, 20 July 2007 (UTC)

I've never noticed that before. I guess it's conserved patterns of gene expression for fur mottling. here's a great shot. Bendž|Ť 21:16, 20 July 2007 (UTC)

Mountain Lions (Puma, Cougar, etc. native to the Americas) also have kittens with tabby markings, but the adult is an even tawny color. The tabby markings provide excellent camouflage that is presumably advantageous to the vulnerable kittens. However, these large cats as adults have less need to be camouflaged and so lose their markings as adults. I'd have to check, but I think that almost (if not all) feline kittens have tabby markings regardless of the markings of the adults. This is a bit of a "just-so story", but it is a plausible explanation.--Eriastrum 15:49, 21 July 2007 (UTC)

To domesticate an animal, neotenous (kitten/puppy-like) traits are often selected over many generations. These are usually behavioural, such as a dependent personality, placidity, enjoying a good stroke behind the ear, etc, but I suppose there's no reason why kitten-like markings in adults couldn't be brought out in the breeding process. Bendž|Ť 20:58, 21 July 2007 (UTC)

Mechanical engineering

WHAT IS THE CURRENT CHALLENGES IN MECHANICAL OR MANUFACTURING ENGINEERING?

Mechanical engineering#Frontiers of research in mechanical engineering and the main articles listed therein. Someguy1221 06:09, 20 July 2007 (UTC)

The question I posted below is a perfect example of a current challenge of mechanical engineering... unfortunately. Nimur 06:20, 20 July 2007 (UTC)

The maintenance of old steam pipes?

Atlant 12:23, 20 July 2007 (UTC)

How to unstick all of those CAPS LOCK keys by the look of it. SteveBaker 01:10, 21 July 2007 (UTC)

More like sticky shift keys? Capuchin 07:59, 23 July 2007 (UTC)

IDEALLY how to make something out of nothing! Free energy is out there if we can just harvest it. Each Lightning bolt can power a city for a day, but how do you capture the energy (giant batteries connected to very high lightning towers in high storm areas like central florida??) More sun energy hits the earth each day than we could ever use, but how to capture it. Combatting waste is the avenue and to save our energy that is given by the sun and earth rather than let it get away. TripleBatteryLife 16:59, 23 July 2007 (UTC)

Generator Problem

Greetings Science Reference Deskers! One of our field teams is deploying a remote site in Alaska as we speak. They have purchased the Troy-bilt 5550 Watt Generator and have an interesting "show-stopper" of a problem. The generator has a pull-cord to start its engine, and apparently this cord "is stuck" and "will not pull." Our home-office version does not have this problem, and the generator seems to work fine here in the lab. What in the world could be causing this issue? The engine has been properly fueled and oiled and is brand-new. Unfortunately, the team is in too remote a site to easily "buy a new one" and we are furiously trying to get it working. Any small-engine experts know what we should do? Nimur 06:08, 20 July 2007 (UTC)

Ice? —Bromskloss 07:21, 20 July 2007 (UTC)

It's about 60 degrees Fahrenheit now, though. Nimur 07:24, 20 July 2007 (UTC)

Perhaps the cord is tangled and looped over itself. Or perhaps some extraneous matter has got into the clutch or something. You might have to take off the cover to see what is happening! Did the generator get transported with oil in it? If it was placed on its side, oil could have gummed up the spark plugs and stop it starting - though it should still turn over. TO fix this problem take out the spark plugs and clean them. GB 07:46, 20 July 2007 (UTC)

I'm no small-engine expert, but I agree with GB's suggestion about the cord. I think there's probably an easily-removeable cover over the pull-cord mechanism; your field team should remove that and see if anything's amiss. If there's nothing obviously wrong with the cord, they should then figure out some way of gripping the pulley (the one around which the pullcord is wound) very tightly and securely, and trying to turn it, slowly, by a small amount. It's at least somewhat likely that something in the engine has gotten stuck or seized, and that a larger force (larger than can be applied using the pullord, smaller than it would take to break anything) will unstick the engine, after which the pullcord can again be used to turn it over, after which (cross your fingers!) it will start. —Steve Summit (talk) 11:50, 20 July 2007 (UTC)

[But if the pullcord won't pull and the engine won't turn over at all, the spark plugs are definitely not the problem.]

Liquid lock might be a problem, especially if the generator set was tipped to some bizarre angle during shipment so oil or gasoline filled the cylinder(s). Remove the spark plug(s) and see if the engine can be cranked using the pull-cord.

Atlant 12:32, 20 July 2007 (UTC)

Definately a good idea to try, also there is a chance of glazing loose in the cylinder if the generator has been run with no load and then transported. Have a look in the cylinder.Polypipe Wrangler 11:06, 21 July 2007 (UTC)

It's a smaller engine, but I have known my lawnmower pull start to jam. I have gotten it loose by repeated jerking and releasing the cord. Cussing it in the process seemed to help. Not sure exactly what the mechanism of it getting stuck was. Edison 20:51, 20 July 2007 (UTC)

If it's brand new (never been started) it may have something in it to prevent the parts from moving during shipment and causing damage. If so, the instructions would likely include a way to remove such devices. StuRat 02:09, 23 July 2007 (UTC)

If it's brand new and has a locking device, the locking device probably also has a big bold message that says something like "No oil in engine; add 10 oz. oil before starting!". Follow that advice ;-).

Atlant 12:43, 23 July 2007 (UTC)

OIL TURNS TO CONCRETE WHEN FROZEN! ! You'll have to heat up the generator then drain the oil and then put in lighter oil (in alaska 5-20w was common. I actually had to heat my oil pan with a coleman camp stove for 3 hours in 70 below weather in canada (beavercreek BC) to get it to start. Don't break your rope trying to hard. You can use gasoline in a metal pan to create heat if you have no other way. Hope this helps! TripleBatteryLife 17:06, 23 July 2007 (UTC)

However, as the author said "It's about 60 degrees Fahrenheit now." StuRat 07:25, 24 July 2007 (UTC)

Principle of the hand pump

WHAT IS THE PRINCIPLE OF HAND PUMP?

Firstly, let me be the first to commend you for your eloquent and polite question. As for your actual question, there's some very sketchy information at hand pump - but maybe some of the types of hand pump may help you find specific information about how these work. Google is your friend. Good luck. Aaadddaaammm 09:52, 20 July 2007 (UTC)

Pump#Positive displacement pumps seems to be the right place to look.

Atlant 12:34, 20 July 2007 (UTC)

Are humans the most successful creatures on earth?

In terms of numbers of individuals, or in terms of total biomass, where are humans in the success stakes compared with other species?

And I'm always surprised to learn that there are more for example cows in my country than humans - do they have secret underground cities? 80.2.192.45 11:10, 20 July 2007 (UTC)

Insects would be far more populous than humans or cows. Ants for instance are pretty kick ass when it comes to huge numbers. The most 'sucessful' 'creatures' however could possible be considered bateria (5×10³⁰ in the world according to the article) or viruses although it all depends which criteria you choose to use to measure success. Lanfear's Bane

Although, neither insects, viruses nor bacteria are a species. But there could well be one species from within these groups that fits the required criteria. It always grates with me when people say things like 'humans have only been around so long, dinosaurs ruled the earth for millions of years'. Well that's hardly a fair comparison! Yes defining success is difficult, there are more cows because humans grow them for food, who's the more successful there? Anyway to quote from our Biomass (ecology) article: 'The most successful animal, in terms of biomass, is the Antarctic krill, Euphausia superba, with a biomass of probably over 500 million tons, roughly twice the total biomass of humans.' Cyta 11:37, 20 July 2007 (UTC)

That very last figure sounds a tad dubious; although they don't state whether they mean wet or dry mass, the fact that the overall source seems to be about krill as food suggests that they mean wet mass. Assuming an average body mass of 70 kg (slightly less than highly developed countries, slightly more than less economically developed countries), * 6.5 billion people gives an approximate biomass of 455 million tonnes; virtually the same as the krill. Laïka 17:49, 20 July 2007 (UTC)

You're forgetting that a large fraction of humanity (as represented by that 6.5bn figure) are children - some a light as a couple of kilos. It wouldn't surprise me to find that the average human weighed in at 35kg on that basis. So I can believe Krill have out out-massed 2:1. SteveBaker 01:08, 21 July 2007 (UTC)

Not only that but given that the majority of people are from less economically developed countries, 70 kg seems a little high even for adults to me. Nil Einne 12:55, 23 July 2007 (UTC)

Let's look at some different ways to measure success:

1) Number of individuals alive now. We rate very low on this scale, as would all large organisms (although we rate well relative to other large organisms).

2) Largest biomass. We rate quite well here, although perhaps not quite at the top.

3) Longest species longevity. We're pretty pathetic here, being a relatively recent species.

4) Longest individual longevity. We're not so good here, as many plant species, and a few animals, have us beat.

5) Ability to alter our environment. We may be in the lead here, although the alterations to our environment aren't always to our advantage, like global warming.

6) Intelligence. We have the other species beat by a long shot here.

7) Range of habitats. We are quite high in the range of habitats on land we can manage. However, as there is so much more water than land on Earth, some marine species would likely beat us here.

However, if we can manage to survive long enough to spread our species to other worlds, this might increase our biomass (and eventually species longevity) well beyond other species.

Reflection

Hi, I was reading the Wikipedia article on 'Reflection' and came across this phrase which I don't really comprehend - 'the photon absorbed by the molecule may match energetic levels of the molecule. I would be very grateful if anyone could explain what it means. Thanks!

Full context:

As the photon absorbed by the molecule may match energetic levels of the molecule (kinetic, rotational, electronic or vibrational), the photon may not be reemitted or alternatively may lose some of its energy in the process. The emitted photon will have a slightly different level of energy.

When the photon hits the molecule, it gets completely absorbed, adding some form of energy to the molecule. Depending on the original state of the molecule and the amount of energy in the photon, the new state may be stable or unstable. If it's stable, the molecule will not emit a photon, in which case the photon has not been reflected. If it's unstable, the molecule will emit a photon, but not necessarily one with the same amount of energy.

Say that some property of the molecule has stable points at 3, 5, and 12 units of energy. If it's sitting at 3 and a photon with 7 units of energy hits it, it will jump up to 10. 10 is unstable, so the molecule emits enough energy to drop down to 5, the closest stable point. That means that the reflected photon will have only 5 units of energy.

Now imagine that another photon with 7 units of energy hits it. This time, it goes up to 12. 12 is stable, so no photon is emitted, and the photon has been (in the classic sense) absorbed.

Hope that helps! -FunnyMan 11:57, 20 July 2007 (UTC)

The simple fact that is lost in all this physics is the following: If the atoms absorb the photon and immediatly re-emit them in a coherent manner, this is reflection. "Coherent" means that it fits into the phase (the "rhythm" of oscillation) which ensures that the light goes in the right direction. If the photon is absorbed and not re-emitted at all as visible light, then this colour is not reflected. Silver, for example reflects all colours, while copper canot reflect the blue part of the spectrum, and this is why everything refelected off copper (and hence copper itself) has a redish hue. Simon A. 14:58, 20 July 2007 (UTC)

Sharlel Mary Talo Palsy?

My girlfriend's brother has a type of palsy called sharlel mary talo palsy, but I am not sure hoe to spell it so I can't find any information on the subject. If anyone knows the correct spelling of this condition, please advise! Thanx in advance! Steve (removed email signature) —Preceding unsigned comment added by 209.206.132.56 (talk • contribs)

Never heard of that particular name of a palsy, but are you referring to Charcot-Marie-Tooth disease? -- JSBillings 13:44, 20 July 2007 (UTC)

an indelicate question

I noticed when cleaning my bottom in the shower after a bowel movement that there are insoluble, fine sand-like particles from the feces. What kind of substance(s) would these be? --Halcatalyst 14:35, 20 July 2007 (UTC)

For medical advice you should consult your doctor. It could however simply be sand. Have you been to the beach recently? Lanfear's Bane

I'm not looking for medical advice, since I'm not experiencing any illness, and no, I haven't been to the beach in a long time. Rather, I take this to be a normal occurrence which I've noticed for a long time, and I'm looking for information related to intestinal processing, presumably with respect to normal diet. --Halcatalyst 15:50, 20 July 2007 (UTC)

Do you eat a lot of bread made from stone-ground flour? DuncanHill 20:14, 20 July 2007 (UTC)

No. I'm wondering if these particles might be accumulations of minerals in the diet. (I'm pretty sure it isn't just me. I've noticed it because my shower drain is flat and in a couple of spots the water (and particulate debris) doesn't flow away. It helps that the floor is white.) --Halcatalyst 21:04, 20 July 2007 (UTC)

They may be the stone-like little gritty things you find in some fruit auch as pears. They might be something like gall stones although perhaps not in such quantity. Or they might be bits of peanuts or other nuts. A lot of things like sweetcorn come out of your rear end unchanged.

There is often grit in fresh veggies, like celery, so perhaps you need to wash them more thoroughly. Also, if you eat things with bones in them, like sardines, perhaps a rounded piece of bone makes it through the digestive system. StuRat 01:12, 23 July 2007 (UTC)

It could be small seeds. Or if you've eaten low-quality hamburgers, sausages etc it could be little bits of ground up bone. Might even be the remains of red-blood cells which, I understand, are excreted when old. Have you looked at them under a microscope?

A microscope! Of course, that would be the way to go. But I have none....

It dawned on me that I could look up Human feces. It didn't say anything about small particles, but it would be hard to imagine that feces would be entirely water/soap soluble, I guess. --Halcatalyst 21:39, 24 July 2007 (UTC)

Psychopathy vs suicide rate

I have been reading the Wikipedia article on psychopathy, and it is said that Hervey Cleckley asserts that psychopaths are not likely to commit suicide as they score high on both of the PCL-R factors. Yet it is said that Factor 1 is not related (istead of negatively related) to suicide and factor 2 strongly correlated to suicide, shouldn't that mean that psychopaths should also be very susceptible to suicide? Thanks! —Preceding unsigned comment added by 58.153.96.35 (talk • contribs)

Pollination of sacred fig (peepul tree, bo tree)

Britannica says: "Each fig species are pollinated by species-specific wasps." (Under Ficus) Is this true? Sacred fig (aka as peepul or bo tree) has very tiny fruit. Does pollination occur with the help of fig wasp in bo tree? Thanks in advance for your valuable instruction. —Preceding unsigned comment added by 58.216.233.166 (talk • contribs)

Another question Sacred fig says that Peepal ..."is a species of banyan fig native to Nepal and India"... Is this true? Isn't banyan another species of the Ficus genus?

Also, does peepul send out aerial roots like banyan? As we know, banyans can have massive prop roots which grow into parallel trunks as this image shows. Though I haven't seen a peepul with such prop roots, peepul always have extremely gnarled trunk, as if many many smaller trunks stuck together to form the trunk, as seen in this image

LASER RADAR (LIDAR) operated by police

help. is there any way to beat the lazar radar used by police. the make is atlantis.

thanks,

u.k.nown —Preceding unsigned comment added by 204.138.85.6 (talk • contribs)

We have an encyclopedia article about LIDAR if you care to read it. Friday (talk) 18:07, 20 July 2007 (UTC)

Laser ranging is particularly sensitive; far more so than plain radar, so it is very difficult (read impossible) to beat, even if you were to coat your car with matt black paint which would normally beat a light-operated device (laser ranging is so powerful that it can even pick up reflections of thin clouds of water vapour). There is only one surefire method: slow down. Of course, this is only good for a laser radar; the easiest way to beat a lazar radar is to take a mixture of rifampicin, dapsone and clofazimine once a day for the leprosy... Laïka 18:17, 20 July 2007 (UTC)

When my father was trained on the laser radar gun, he was told to aim for the headlights because they provide a much better reflective surface. So, if you are paining your car flat black, ensure you either remove or paint over the headlights also - and don't drive at night. -- Kainaw^(what?) 19:12, 20 July 2007 (UTC)

Here in Texas, they train the cops to aim the laser at the front license plate - and only to go for the headlights if there isn't a front plate (which is illegal in Texas anyway). The license plate has a retroreflective coating and the headlights have parabolic reflectors - both ought to give a nice strong return for the laser. Painting over your headlights probably wouldn't help - but it would be illegal anyway - I'm betting the speeding ticket would be cheaper! SteveBaker 05:31, 21 July 2007 (UTC)

Given that our Mr. Nown knows the model of the laser gun that caught him, I'm guessing his court date is already set, and that's the venue where he hopes to "beat" it. (Requiring, of course, a whole different set of strategies.) —Steve Summit (talk) 12:05, 21 July 2007 (UTC)

...which would require us to offer legal advice - which we aren't allowed to do. SteveBaker 14:13, 21 July 2007 (UTC)

Well, if you can prove variable speed of light in a court of law, not only would you quash your conviction, but probably get rather rich and famous off it... Laïka 19:05, 21 July 2007 (UTC)

The speed of light is variable - it depends on the material it's travelling though - it's only the speed of light in vacuum that's constant. SteveBaker 21:54, 21 July 2007 (UTC)

I have been told that one can buy effective LIDAR jammers that use infrared light-emitting diodes mounted around one's front license plate frame. These LEDs re arranged to emit a pseudorandom binary sequence that the LIDAR cannot analyze. That is, the LIDAR can't locate its own pulse returns among the many flashes of LED light that it sees coming back at it.

Last I knew, these were generally not illegal in the United States (certainly don't violate any FCC regs), but that would venture into the "legal advice" domain.

I do not now own nor have ever owned or operated such a device, so I can't really vouch for their effectiveness or legality.

Atlant 12:39, 23 July 2007 (UTC)

This technical document explains things very nicely: http://www.mr2.com/TEXT/FAQonLidar.html - the conclusion seems to be that LIDAR is effective, hard to avoid and hard to jam. As for the legality - as it points out, there is a general "Interfering with the duties of a police officer" offense that probably covers all efforts to avoid lidar speed detection. SteveBaker 13:06, 23 July 2007 (UTC)

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thank-you everyone for responding with all the useful information. sorry for delay in responding, was indisposed. you people are fantastic. By the way I was questioning this as three cars were pulled over at the same time. I did not think that was possible or even allowed. U.N.Nown.

Hypothetically moving a mountain

If one were to move a mountain or the weight equivalent to one, what would be the most scientifically sound way to do so. Even though impossible, what would be the closest way?

A bunch of dump trucks. Clem 19:05, 20 July 2007 (UTC)

Correct - divide and conquer. -- Kainaw^(what?) 19:10, 20 July 2007 (UTC)

Don't take my word for it, but I'd consider the following. First of all, we don't want to lift the mountain at all, because the work necessary to lift a mountain even a small amount would be enormous. I can imagine slowing cutting the base of the mountain, replacing the stone removed by two thick layers of solid steel (that could support the wieght of the mountain); the bottom one attached to the ground and the rop one attached to the base of the mountain. If you place a thin layer of teflon on the contact surfaces and a very thin layer of lubricating liquid, you could get the friction down quite a lot. Also, to further reduce the friction, you could use maglev technology to reduce the normal force produced at the contact surface (we probably couldn't get the mountain to levitate, but the repulsion would have an effect equivalent to further reducing the fiction coefficient). Once all that was done, maybe you could slowly slide the mountain to one side. --Waldsen 19:11, 20 July 2007 (UTC)

p.s. My way is nice to imagine, but in practice it would be an engineering nightmare (practically impossible). --Waldsen 19:16, 20 July 2007 (UTC)

You would have an extremely long chute that could remove the material from the top as far away as possible, so the rock would initially be distributed in a circle around the mountain. As the mountain got lower you'd use a shorter chute(s). The mountain would be moved as you said. You didnt say anything about keeping it the same shape. 80.0.105.59 19:21, 20 July 2007 (UTC)

I think it said in a documentary I saw that they pretty much fully demolished a mountain during the construction of KIX in order to build the artificial island. Philc 19:41, 20 July 2007 (UTC)

How large is the cross section of the mountain in the plane where it is to be cut, and what is its mass? Large buildings clearly are orders of magnitude less massive than a typical mountain, but they have been separated from their foundation and placed on springs for earthquake protection. Large buildings, even lighthouses, have been jacked up and moved by house movers.Cleopatra's Needle is the name given to several stone obelisks which were move between countries in ancient times and more recently. Our ancestors 5000 years could move large stones with rollers or skids and muscle power. Saturn V moon rockets and the Space Shuttle are routinely driven to the launch pad by a gargantuan lowboy. So in principle, I would prepare a roadbed which could support the weight, perhaps using multiple parallel rails and wheeled assemblies on either side similar to but vastly scaled up from railroad wheels and axles. Perhaps multiple wheels, rails, and bearings in an assembly on each side. Hydraulic jacks would take up the strain to support it after supporting beams were inserted in holes drilled through it, and below those holes the cut would be made completely through it. Roll it along the roadbed to the new site where a foundation has been prepared, lower it into place, remove the beams, cement up the holes, which would be below the finished grad, and voila. Rather than assuming it is impossible, it would be a good exercise for a mechanical engineer to calculate the upper limit of early 21st century technology to move a mountain. Assuming cost was no object, like the Pyramids, Space Program, or the present global war budget, then it could be cut into the largest hunks that today's technology can move, moved, and reassembled at the destination. (Number the pieces to keep track and avoid a jigsaw puzzle). The Abu Simbel temple, carved out of solid stone, was moved in this way from 1964 to 1968 at a cost of $80,000,000 to save the World Heritage feature from being submerged by a lake. I don't know the total mass of stone moved or the max weight of each block.Edison 20:41, 20 July 2007 (UTC)

Edward Teller used to quip, "If your mountain is not in the right place, just drop us a card." --24.147.86.187 21:36, 20 July 2007 (UTC)

Well, you have not specified whether the mountain must be intact after its move. In Seattle the city did actually “move” a mountain at one time. They just aimed a bunch of fire hoses at it for a while and washed in into the Puget Sound, I believe. It probably killed of a lot of the salmon. These days that would never be allowed. --S.dedalus 22:28, 20 July 2007 (UTC)

Heh I was going to mention the Denny Regrade myself. Then there is Mountaintop removal mining, which essentially moves mountains. The question is, do you want the mountain to be in the same shape after you move it, or is it ok to just be a thick flat layer of debris? Pfly 01:12, 21 July 2007 (UTC)

Undermine the mountain on an inclined plane, replacing the rubble with sand (like in the old mines at Broken Hill) and fitting high pressure water pipes as you go. Then turn the water on and stand clear. Even better if the last part is done just before an earthquake. Round desert sand should work better than sea sand. Polypipe Wrangler 11:23, 21 July 2007 (UTC)

Use a river. But, of course, only if you are moving the mountain downhill. Otherwise, announce there's coal under the mountain and have a mining company move it for you.

Atlant 12:48, 23 July 2007 (UTC)

The book How Would You Move Mount Fuji? tells how a number of Microsofties would try it. --TotoBaggins 18:18, 23 July 2007 (UTC)

Chuck Norris (somebody had to say it), and with the slicing through the bottom of the mountain, assuming it was feasible, might make moving the mountain easier if cut at incline, so perhaps it could be sluoghed onto rollers for more moving without any or realatively little proding, it addition to teflon69.29.94.95 05:51, 26 July 2007 (UTC)

batteries constructed on chip same as transistors on ICs

Is there a battery or electricity storage device that is constructed on a chip such that the chemical/physical components of the capacitor or electrochemical cell (LiFePo4) have been implemented at the nanoscopic level? If so has such technology been stacked and used to provide power for larger battery powered devices in place of a conventional battery? Clem 19:04, 20 July 2007 (UTC)

I remember reading somewhere on the Internet recently about a little device that gets electrical energy from vibrations and thus powers things without batteries. 80.0.105.59 19:14, 20 July 2007 (UTC)

The article Micropower would be a good place for covering the new device which gets power from vibrations or the battery on a chip , but those have apparently not been added yet. A battery built into a chip sounds like a very high expense item, if the implication is that both the battery and the device it powers is on the chip. Then when the battery gets low, you have to replace the device as well? At the present time, PCs have a backup battery with a shelf life odf several years to keep configuration info memory powered, and it is fairly easy to replace the battery. A backup battery may not have to furnish appreciable current as long as the device has power, and the drain can be extremely snall even without power. I suppose there is no reason a microscopic battery could not be built, and be capable of furnishing several volts, but the amp-hours would have to be correspondingly minute. Edison 20:21, 20 July 2007 (UTC)

Well I would assume any battery design committed to a chip would also be rechargeable especially if charged from vibrations. But what I am getting at is more like a conventional battery that has been reproduced at the microscopic level not to power an included circuit but rather as one of a trillion basic cells that would all be wired together as an alternative to say using airgell to maximize the surface interface between say lead and sulphuric acid. Clem 23:57, 20 July 2007 (UTC)

I recall an article on the construction of supercapacitors using bioengineering. The growth of some organism through a carbon filament created a capcitor with a great amount of surface area. No link, sorry!

Natural biological capacitors, such as phospholipid membranes, have a dielectric breakdown constant on the same order as materials used to insulate high tension power lines, as I recall. The problem, of course, is that they're tiny and generally useless as capacitors except as nature intended, but they have intriguing possibilities. Someguy1221 03:45, 21 July 2007 (UTC)

Generally speaking, integrated circuit chips and on-going chemical reactions don't get along well. Those chips that seem to contain a battery (some non-volatile CMOS RAMs, time-of-year clocks, and the like) usually contain an actual, discrete lithium battery in the overall package.

Atlant 12:52, 23 July 2007 (UTC)

fates worse than nature

this is with reference to the question asked a few days back. i was thinking about these parasitoids and their amazing ability to control the minds of the hapless bugs. is it possible for them to evolve to something that could possibly target humans? for instance, like that ant which was made to wait on the grass to be eaten by the cow - i would be quite upset(to say the least!) if i were made to, say, enter a river full of crocs just to complete the life cycle of a parasitoid! 59.180.95.229 21:45, 20 July 2007 (UTC)RSP

See toxoplasmosis#Behavioral changes for a possible example of a known parasite that may impact human behaviour. Dragons flight 22:01, 20 July 2007 (UTC)

It wasn't in the article, but I saw something the other week which related the supposed tendency of toxoplasmosis to make women more affectionate to the sterotype of the ...... woman with a houseful of cats. hmm. Gzuckier 15:44, 23 July 2007 (UTC)

Also rabies for a definite and easily noticeable (and nasty) one. —Ilmari Karonen (talk) 11:21, 21 July 2007 (UTC)

Well, rhinovirus makes you sneeze. It's the same idea. Similarly, cholera, for instance, makes you generate large quantities of diarrhea which is virtually colorless and odorless, and is highly infectious. The advantages for the spreading of the disease over having nasty diarrhea which would make nurses etc. wash their hands and the sheets etc. thoroughly are obvious. It doesn't always have to be changes in the brain to change behavior. And then there's rabies, which makes normally shy animals wander out in the street at noon and pick fights. etc. Gzuckier 15:42, 23 July 2007 (UTC)

July 21

Cough cough

Can any animal cough in its sleep? —Pengo 00:35, 21 July 2007 (UTC)

Yes - my dogs do. SteveBaker 01:01, 21 July 2007 (UTC)

So why don't humans if dogs do? —Pengo 15:16, 21 July 2007 (UTC)

My wife does.

So now we have anecdotal evidence on two species of animals. --Halcatalyst 21:23, 21 July 2007 (UTC)

Economics Question

Just a bit stuck. What possible circumstances could lead to there being a concave curve of production possibility, i.e., circumstances in which the opportunity cost of a product falls as its production increases, I am only looking in simple 2-product systems, but I cant quite grasp this. Philc 01:27, 21 July 2007 (UTC)

I'm no economist, but I'd assume any situation involving economies of scale could easily make at least part of the curve concave. —Ilmari Karonen (talk) 11:26, 21 July 2007 (UTC)

Agreed. Let's say you need a fweeble to make a fwap and need a fwizzle to male a fwaz, and both fweebles and fwizzles are quite expensive (same high price) if you buy them retail, but you can only buy them wholesale (same low price) if you buy 1000 at a time. Then let's say you can afford 1000 of one at the wholesale price, but not 1000 of both. In that case, you would do best to build only fwaps or fwazzes, not both. StuRat 00:39, 23 July 2007 (UTC)

Is this proof of seagull intelligence?

http://news.bbc.co.uk/1/hi/scotland/north_east/6907994.stm

The bird has a favourite flavour of Doritos, it knows what's in the bag and it knows how to open the bag. Any thoughts? --84.64.224.162 01:42, 21 July 2007 (UTC)

One of my dogs is fairly adept at opening food packaging without tearing it, never seen a bird do that though...My own thoughts, the bird probably figured it out by trial and error. It has to figure out what normal seagully foods to eat anyway, so they must have an ability to learn things of that nature. Someguy1221 01:57, 21 July 2007 (UTC)

Gulls clearly do have a concept of 'things inside other things' - they routinely rip open rubbish bags and discarded takeaway containers to see if there's anything edible inside (I once saw a gull open a margarine tub, have a look inside, then start pecking away at the scrapings that were left inside). So, here we have a gull demonstrating that it understands the concept of of 'things inside things inside things' - tasty corn treats inside a shiny plastic bag, inside that strange cave that the apes use. --Kurt Shaped Box 08:32, 21 July 2007 (UTC)

While seagulls may have a fairly good understanding of human packaging equaling food (they often scavenge garbage dumps), I recall, as a young boy I'd add, feeding a seagull a whole stick of butter. He/She ate it up in one gulp, now how intelligent is that? --Cody.Pope 10:14, 21 July 2007 (UTC)

Pretty smart, IMO. Get it down his neck quickly so he doesn't have to share it with the other gulls against his will. He can digest it later... :) --Kurt Shaped Box 10:37, 21 July 2007 (UTC)

Swallowing impossibly large objects is something many gulls do. I suppose that it is an adaptation to being a scavenger and eater of carrion. I have often seen gulls with entire sea stars jambed halfway down their throats walking around for hours and finally swallowing it. These are sea stars 4 or 5 inches in diameter! This is on the central coast of California and the gulls are usually the large Western Gulls.--Eriastrum 15:39, 21 July 2007 (UTC)

Were they actually in the bird's crop, or do you mean that the gull was walking around with the thing half-swallowed and hanging out of its mouth? Gulls can fit enormous amounts of food into their crops - sometimes it looks like they've swallowed a baseball whole. It's pretty normal for them - if they discover that an item of food is slightly too big or hard, they vomit it back up immediately. --Kurt Shaped Box 21:01, 21 July 2007 (UTC)

The gulls with the sea stars have initially 2 or 3 arms hanging out of their beaks. After an hour or more there is just a big lump in their throat. I've never actually timed this, but I've never seen that they vomit it up again. If you do an image search on google using keywords gull and starfish, you will see what I'm talking about.--Eriastrum 18:20, 22 July 2007 (UTC)

Interesting, thanks - I see what you mean. I'm quite surprised that the other gulls don't follow the one with the half-swallowed crustacean and try to forcibly yank the thing back up out of its throat... --Kurt Shaped Box 20:28, 22 July 2007 (UTC)

(re-indent)Remember that seastars are not delectable, crunchy, yummy crustaceans! They are spiny, hard echinoderms. So my guess is that it is not looked at by other gulls as especially desirable: it's hard to digest and obviously takes a considerable investment in time to fully swallow.--Eriastrum 22:31, 22 July 2007 (UTC)

So Kurt, would you please stop organizing the gulls into a master criminal conspiracy? Thank you. Dragons flight 22:35, 22 July 2007 (UTC)

Don't say that I didn't warn you. --Kurt Shaped Box 21:09, 23 July 2007 (UTC)

I don't think it's anything special. Lions know what's in the Zebra "bag." They selectively chase it down, open the "bag" and eat the goods. Seagulls eat shellfish which they drop from the air to open on the rocks below. this behavior seems pretty common. --Tbeatty 05:48, 24 July 2007 (UTC)

Ice hardness

Is water ice harder at -40 degrees than it is at -5 degrees, or is ice the same hardness no matter what? 68.231.151.161 01:47, 21 July 2007 (UTC)

I'm guessing but from experience in both refrigeration work and in winter environments, yes. (Also vehicle travel over frozen lakes would also attest to the fact that sustain warm periods can greatly reduce both the thickness and the hardness of ice.) Clem 03:03, 21 July 2007 (UTC)

Yes, the "hardness" of ice is inversely proportional to the temperature (i.e. harder ice at lower temps). Here is a ref that claims ice at 0°C is a 1.5 on the Mohs hardness scale, while its Mohs 6 at -70°C - about 50х harder. -- MarcoTolo 03:12, 21 July 2007 (UTC)

"Harder ice at lower temps" I believe; "inversely proportional", don't be ridiculous. Where do you see a ratio of 50 between the two temperatures you cite? --Anonymous, July 21, 07:22 (UTC).

Don't worry, anon, you can always concoct a scale on which it works (provided you ignore all other temperatures). Someguy1221 08:29, 21 July 2007 (UTC)

"Is inversely proportional to" is not the right language here; "varies inversely with" should be used instead. (As I understand it, hardness scales are ordinal scales, not ratio scales.) --72.78.102.77 11:26, 21 July 2007 (UTC)

Moh's is indeed an ordinal scale, its values are based on the hardness of various readily-available minerals, which is of great utility for mineralogical diagnosis, but less so for engineering purposes. Other hardness scales include the Vickers hardness scale. DuncanHill 15:49, 21 July 2007 (UTC)

Skaters report that skating at very cold temperatures is harder, supposedly because the thin film of water melted under the pressure of the blade doesn't melt when it's too cold. Gzuckier 15:46, 23 July 2007 (UTC)

Sky colour question

Within an atmosphere humans can breathe without difficulty, is it possible for the sky to be a colour besides blue (during the day)? If it can, which colours? I checked the Rayleigh scattering article, but the relevant information was written too technically for me to get anything out of. 142.59.225.165 04:46, 21 July 2007 (UTC)

Yes - it's possible. If the earth was orbiting a red giant like Betelgeuse or something - we wouldn't have a blue sky because there would be no blue light there in the first place - so it's clearly possible to have a different coloured sky. I suppose it's possible that the particles that are doing the scattering could be a dramatically different size on some different world - that would result in a differently coloured sky too...but that's a harder sell because dramatically bigger particles would probably just settle out leaving a black sky. Obviously the sky can be grey or white - it is right here on earth on cloudy days. Imagine a planet with permenant cloud cover and you have a white/grey sky. SteveBaker 05:26, 21 July 2007 (UTC)

feline table manners

Do cats other than housecats (F. silvestris catus) play with their prey? —Tamfang 07:47, 21 July 2007 (UTC)

Yes they do. What better way to learn about the behaviour/movements of your prey? —The preceding unsigned comment was added by Canis sylvaticus (talk • contribs) 08:24, 21 July 2007 (UTC)

I believe the cubs of most if not all felidae play with their prey — it's how they learn to hunt. The mother brings live prey to the cubs and lets them play with it, thereby showing them what to hunt and how to catch it. As Canis sylvaticus points out, I'd expect this to be common behavior for most at least moderately intelligent predators. The persistence of this behavior to adulthood in housecats may simply be a symptom of the neoteny associated with domestication, although I believe I've also heard of wild adult felines playing with prey when they're reasonably sated and in no hurry to kill and eat it. —Ilmari Karonen (talk) 11:41, 21 July 2007 (UTC)

Barium

Does Barium conduct sound? 168.209.97.34 12:05, 21 July 2007 (UTC)

other metals conduct sound, I'd imagine barium is no different - the only possibility for it's not conducting sound would be if it was a rubbery material.

Does anyone know if barium has a rubbery texture?83.100.251.27 12:15, 21 July 2007 (UTC)

http://www.allmeasures.com/Formulae/enwiki/static/formulae/speedofsound/97.htm

Barium is not like rubber - it is a metal! GB 01:54, 23 July 2007 (UTC)

centrifugal pump

after priming why do we close the outlet valve of a centrifugal pump?59.92.74.83 12:05, 21 July 2007 (UTC)

Do we? If we do, it is to stop anything getting in or out. The purpose of priming a pump is to fill it with liquid, since attempting to pump air could damage it. If you have been instructed to close the outlet valve, this will presumably be to stop air getting into the pump while it is not in use.--Shantavira|^{feed me} 13:32, 21 July 2007 (UTC)

sorry, i did not put it clearly.After priming till the pressure reaches it's rated value , the outlet valve is kept closed and then opened slowly,why?

Mouth-movements of puppets or animations

I assume that the voices of animations like the Simpsons are recorded first, and then the animations are fitted to the voices. I wonder how they decide when to open and close the mouths? But this Supermarionation article, talking about Thunderbird puppets, says:

"The heads contained solenoid motors that created the synchronised mouth movements for dialogue and other functions. The voice synchronisation was achieved by using a specially designed audio filter which was actuated by the signal from the pre-recorded tapes of the voice actors; this filter would convert the signal into a series of pulses which then travelled down the wire to the solenoids controlling the puppet's lips, creating lip movements that were precisely synchronised with the dialogue."

What would the audio filter consist of, and what features in the sound signal did it pick up on? Thanks 80.0.110.193 13:27, 21 July 2007 (UTC)

There is certainly computer software out there that attempts to do at least a basic fit of lipsynch to sound - but generally you need an animator to come in and fix up errors at the end. The special features in the Thunderbird DVD set talks about the automatic gadget - but doesn't go into details. Since they only had to open and shut the mouth, they didn't have to have anything anywhere near as sophisticated as modern animators expect. They were doing this stuff in the early 1960's well before Thunderbirds - Stingray, Fireball XL5 and Supercar all seem to use the same techniques - but I don't think Four Feather Falls did (although the mouths were still moved by solenoids). That pre-dates most fancy modern electronics so it couldn't have been much more complex than a set of filters. It would be really interesting to know what they did in detail. SteveBaker 14:09, 21 July 2007 (UTC)

Indeed, I believe the Teddy Ruxpin doll also used a technology somewhat similar to this. Though the mouth motions themselves were recorded on the tape in a "hidden" track and not made on the fly, he probably represented the nascent stages of a consumer version of such technology. --Cody.Pope 14:33, 21 July 2007 (UTC)

I had a toy which also "spoke" but it was just in response to sound. You could make it "talk" by just speaking very close to its little microphone. It wasn't discerning — if you clapped your hands it would also "speak". It's probably a very simple sound-detecting circuit. --24.147.86.187 20:25, 22 July 2007 (UTC)

Honeysuckle species

I'm looking for a species name on this picture: http://www.flickr.com/photos/skenmy/864121885/in/photostream/ - I know it's a Honeysuckle but I'm wondering which species of honeysuckle it is, any help would be much appreciated! --Skenmy^(t•c•n) 15:26, 21 July 2007 (UTC)

There are quite a few species and cultivars of Lonicera. Where did you take the photo? Europe, Britian, Australia, the U.S.? Was it growing in a garden or was it a native plant? What are the leaves like?--Eriastrum 15:33, 21 July 2007 (UTC)

The photo was taken in a British garden today, as far as I know it's a native as it's not in a pot. The leaves are dark green, opaque, oval shaped, few on the stalk. A picture of the same plant earlier in the year is here: http://www.flickr.com/photos/skenmy/488629643/in/set-72157594370422977/ --Skenmy^(t•c•n) 17:25, 21 July 2007 (UTC)

I'm certainly not familiar with Lonicera species native to Britain (I live in California), but I doubt it is a native species. It looks to me like the hybrid Lonicera X heckrottii, known as Goldflame Honeysuckle. It is commonly grown in the U.S. and in Europe, I believe. It is indeed a beautiful type of Honeysuckle. Try doing an image search on Google to see if it matches your plant.--Eriastrum 19:23, 21 July 2007 (UTC)

That looks perfect to me! Thanks guys! --Skenmy^(t•c•n) 21:55, 21 July 2007 (UTC)

colour of compounds

i have learnt something in chemistry which goes lke this: the colour of a compound is the complementary of the wavelength of photon absorbed, when an electron jumps to a higher energy state. but in equilibrium, the no of electrons jumping up have to be equal to the no of electrons falling back, emitting the same wavelength photon(corresponding to the energy difference), so shouldnt the net result be white always? — Preceding unsigned comment added by 59.180.4.84 (talk • contribs)

Yes, but not all electrons will "fall back" through the same path. Some will jump up and then down, but some will jump up, change vibrational states, change multiplicity, and/or release the energy at other wavelengths or with no radiation at all. I am looking for a diagram on Wikipedia that is printed in almost every chemistry textbook, but I can't find it. I used a version I made in a report once and may post it, although I'm afraid it may not be 100% completely right. It would certainly help spruce up the articles on phosphorescence, fluorescence, intersystem crossing, etc, which look like they could use some help. --Bennybp 18:16, 21 July 2007 (UTC)

I posted the diagram on my webpage here. I think it needs a little touching up and updating before adding to Wikipedia, but the general ideas are there. Just a note, ISC stands for intersystem crossing, IC stands for internal conversion. The "up then down" you are thinking of is fluorescence I believe. Let me know if you have any more questions :) --Bennybp 18:33, 21 July 2007 (UTC)

Note that color of compounds involves human perception. Human eyes/brains see color, but they cannot see frequency. For example, a compound which passes a narrow band in the yellow frequencies would look just like a compound which passes two narrow bands; one in red, one in green. And humans have trouble seeing narrow absorption bands, while such bands are glaringly obvious on a specrum graph. If you don't want to involve human eyes and psychophysics, then you want to concentrate on the spectrum of a compound, and not on it's perceived color. --Wjbeaty 14:52, 22 July 2007 (UTC)

thanks. so the electron follows an alternate route back which loses energy at wavelengths which the human eye cannot percieve, to give the compound a specific colour. is that right? 59.180.19.231 17:59, 22 July 2007 (UTC)

Also, if a photon is absorbed and then emitted even at the same wavelength, it may be emitted in a different direction than the incoming photon. As a result, one can stand at a right-angle to a focused light-source on an object and see certain colors emitted (and those photons are hence not propagated in the incident direction). This is in addition to those photons being color-shifted due to various phenomema that occur between absorption and emission. See Raman scattering. DMacks 17:08, 23 July 2007 (UTC)

DNA and its being double-stranded

As I understand it, only one strand of the DNA can have functional genomic function? (Either the 5' strand or 3' strand.) I'm not saying that only 3' or 5' strand exclusively in the entire DNA can have all the genes. Rather, when a specific sequence on a strand contains a gene, the complement strand can't contain a gene. Am I getting all of the above correct?128.163.171.68 20:27, 21 July 2007 (UTC)

More or less. There is no "3' strand" and "5' strand", these are the names of the termini of each strand, named after the deoxyribose carbon molecule at the end. Genes may only be read from the 5' to 3' direction on either strand, but where a coding sequence is found on one strand, the other (complementary) strand is nonsense. So there are genes on both strands, but not at the same time. To form a functional protein from antisense RNA is as probable as reading a poem backwards and finding it makes perfect sense in another language. Protein function is far too complex for that to happen. Bendž|Ť 21:22, 21 July 2007 (UTC)

Should be noted that when the coding strand contains one gene the complementary strand can contain a different gene. This is quite evident in prokaryotes where there is a very high gene density.PvT 21:36, 21 July 2007 (UTC)

Believe it or not, the backwards poem happens more often than you'd think. Every genome so far studied has several: [5]. In addition, there are quite a few genes that partially or completely overlap other genes in the same direction, but frameshifted. (To continue the poem analogy, it's like moving every space in the poem one letter to the right and still getting a poem that makes sense.) They're particularly common in organisms like viruses where there's a strong evolutionary pressure to keep the total amount of genetic material carried compact. TenOfAllTrades(talk) 22:03, 21 July 2007 (UTC)

One example of overlapping genes on opposite strands is the mammalian melanin concentrating hormone gene (MCH) and the antisense-RNA-overlapping-MCH gene (AROM). [6]

Wow, I didn't know that. I guess the flexibilities of the genetic code make this possible; the poem is written in hieroglyphics. Bendž|Ť 07:53, 22 July 2007 (UTC)

I have a vague recollection from when I was in grad school of them finding some virus where both strands of the DNA were coded, so as to give the minimum possible size chromosome. Gzuckier 15:48, 23 July 2007 (UTC)

Viruses are excellent examples of effeiciently packed genomes--many viral genes include sections that are antisense to other genes. — Scientizzle 21:39, 23 July 2007 (UTC)

Thanks for the answers. Any official terms for this phenomenon so I can look it up? 128.163.245.26 10:03, 24 July 2007 (UTC)(question poster)

ethanol production

≥Can Distillers yeast be frozen to remove the ethanol and reactivated? If so what are the temperature limits. —The preceding unsigned comment was added by 207.199.249.186 (talk • contribs) 21:11, 21 July 2007 (UTC)

Freezing is deadly to most organisms, and I would expect yeast to be among them, unless we have evidence to the contrary. StuRat 14:46, 22 July 2007 (UTC)

That's not really true. Cold in itself doesn't really destroy cells the way heat does — any cellular damage from freezing is mostly caused by the uncontrolled formation of ice crystals, and there are many ways to prevent that from happening. In fact, quite a lot of organisms, even multicellular ones, can survive being cooled below the freezing point of water, in some form or other — if they didn't, things would be pretty barren here come spring. Even for organisms that can't do so normally, appropriate freezing techniques can allow succesful revival after freezing. As for yeast, I'm not sure about the fresh kind, but dry yeast can certainly revive and start growing happily after being frozen, thawed and rehydrated. (You could also try Googling for freezing yeast.) —Ilmari Karonen (talk) 16:45, 22 July 2007 (UTC)

You've interpreted frozen to mean "below the freezing point of water", while I took it to mean "has become a solid", which is the more usual definition, I believe. StuRat 00:13, 23 July 2007 (UTC)

For organic materials, "has become a solid" doesn't seem a very useful definition of frozen. For example, isn't the fresh live baker's yeast usually sold in blocks already pretty solid to begin with? As for mixing the yeast in water and freezing the water solid, this doesn't really imply anything about the state of the water inside the yeast cells, which is what matters for their survival.

Re-reading the original question, it does strike me that it may be somewhat misguided to begin with. What the original poster apparently wants is to separate the yeast from the ethanol it produces; while this could be done by freezing the water and the yeast and draining away the ethanol, it would seem more convenient to simply filter out the yeast and then separate the water and the ethanol any way you like (such as by distillation). —Ilmari Karonen (talk) 13:54, 23 July 2007 (UTC)

Since yeast multiplies rapidy, you can take a small sample to keep alive, and process the rest by freezing. GB 02:45, 23 July 2007 (UTC)

Not sure how you intend to separate the alcohol and water by freezing. ?? Gzuckier 15:49, 23 July 2007 (UTC)

Alcohol and water are seperated by freezing in the process known as Freeze distillation or Fractional freezing. DuncanHill 00:11, 24 July 2007 (UTC)

July 22

Aliens

What are the chances that extraterrestrial life would live off of oxygen? Is it possible/likely that they would use a different substance to breathe, because the chemical makeup of the atmosphere of wherever they live would most likely be different than that of Earth. — Preceding unsigned comment added by 68.190.122.58 (talk • contribs)

What makes you assume aliens would need to breathe? Dragons flight 04:56, 22 July 2007 (UTC)

There are even organisms on Earth that don't breath oxygen, see Anaerobic organism. Someguy1221 06:03, 22 July 2007 (UTC)

Oxidation is a good way to get lots of energy out of your "food". (If you doubt this, look at all the energy a fire gives off, which is rapid oxidation.) However, there are other processes for releasing chemical energy from food that don't require oxygen, and free oxygen is also rare in the cosmos (we only have it on Earth due to plants), so those points would support aliens possibly using some other method. StuRat 06:05, 22 July 2007 (UTC)

Iy you are looking for life on other planets, looking for oxygen in the atmosphere is a sensible thing to do. That's not because life needs oxygen to breath, but because life makes oxygen gas as a biproduct of photosynthesis. Theresa Knott | The otter sank 09:26, 22 July 2007 (UTC)

Is it possible? Of course. Is it likely? Difficult to say. We don't have too much evidence to the contrary here of anything larger than bacteria which live off of anything but oxygen. It's hard to make odds when you have a sample size of 1 (for the planet as a whole, anyhow). --24.147.86.187 14:35, 22 July 2007 (UTC)

Depends on how you define life, which is not so easy. For their space program, the USSR once built a robot that was designed to look for life. When they tested it here on Earth it found no signs of life. :)

But one aspect of life must certainly be that it has some form of organisation and for that it needs energy. Oxygen is pretty reactive stuff (as StuRat pointed out), but there are other reactive substances. A chemist had better fill that in. But another thing is that that source of energy needs to be replenished or the environment will run out and the life wil perish (which Theresa hinted at). On Earth, one way that is done is through the interaction between animals and plants, with the animals getting energy out of oxidisation of carbon and the plants using energy from the Sun to reverse that. Without the plants, the animals would run out of oxygen and without animals the plants would 'drown in their own shit', so to say (the way yeast does in a brew, which is why you can never get above 12% with a normal brewing process). Actually, they almost did long ago, until animals came to the rescue.

So you'd need an energy-carrier that is somehow replenished by some other process, be it life or a simpler chemical process. And I have understood that there are not many such cycles possible, but again, you'd better ask a chemist. DirkvdM 19:23, 22 July 2007 (UTC)

Part of this is misleading. Most animals can tolerate 100% oxygen atmospheres, and plants can handle nearly pure oxygen provided small amounts of CO2 are there for metabolism. Life actually flourished during past periods with higher O2 levels, as that could accommodate larger animals. So we don't actually drown in high O2. However, we would burn really really well, which is speculated to be one of the feedbacks that limits oxygen levels on geologic timescales. Dragons flight 20:27, 22 July 2007 (UTC)

Dirk is right (except that plants and animals as we know them came later; it was anaerobic and aerobic microorganisms); he's referring to the Oxygen Catastrophe. Dragon is referring to life of a later time. --Anonymous, July 23, 2007, 01:05 (UTC).

The lack of CO₂ would be the problem for plants, though. StuRat 00:08, 23 July 2007 (UTC)

You can look at life on earth to see other ways for organisms to oxidize. Some bactera convert H₂S to sulfur. Others can change Fe²⁺ to Fe³⁺. Other element conversions are possible, such as producing Chlorine, Bromine or may be even Fluorine as an oxidation waste product. If you found a planet with a Fluorine atmosphere you would have to ask how did this come about? GB 02:04, 23 July 2007 (UTC)

I have to add that oxygen is quite a common element, and so it is quite likely to be used by life. Other common elements in stars are carbon and nitrogen, but not so common on the earth. GB 02:08, 23 July 2007 (UTC)

Herms

Are human Hermaphrodites real? Or are all of those pictures just photoshopped? --59.180.4.84 06:12, 22 July 2007 (UTC)

Yes, there are hermaphroditic people. Many of the pictures you see could be faked, though. Try searching on medical websites for real pictures. A Very Noisy Lolcat 07:27, 22 July 2007 (UTC)

I think the better question is, is there an actual documented case of a human succesfully reproducing (or at least getting an embryo out of it) with him/herself, to which the answer is no (to my knowledge, though I imagine this would be kind of a big thing, so I'll presume no). Alternatively, is there a documented case of a human siring two children, once as a father, and once as a mother, to which, again, the answer would be no. In all cases of human hermaphroditism that I have read of, many of which are heavily documented, only one set of genitalia is functional, or neither is. The problem with human hermaphroditism is that the testicles and ovaries are produced from the same base organ in developing embryos, so unless there is something truly bizarre going on, you can't get both. However, it is possible for a human to have both male and female external genitalia (this has been documented to varying degrees of development thereof), but at least one will be useless in all cases. On there other hand, this paper describes something truly bizarre going on, cases in which children have developed ovaries and testicles. It mentions, however, that such patients are prone to a great manner of abnormalities in these organs, and removal of one is usually performed. It further does not give a positive answer to either of my above rephrasings of the question. It does discuss some of the children reaching puberty and completing development of only one set of genitalia, not both. Someguy1221 20:42, 22 July 2007 (UTC)

Savage Love [7] has a letter from a woman who just discovered that she has two vaginas. It is thought to be “didelphic uterus” in which there are two complete female reproductive systems. Just seemed worth mentioning. She had only had one lover, so apparently was still a virgin in the less used vagina. Edison 21:44, 22 July 2007 (UTC)

172" or 17.2" pipe @ 3,740 psi

One might be surprised how gruesome a totally professional report can be without going into much detail:NIOSH FACE case titled:

Maintenance Man Dies After Being Drawn Into 172-Inch-Diameter Positive Pressure Intake Pipe--Virginia

I'm having a hard time picturing the events described occurring in a pipe 14.3 feet in diameter. Did they forget a decimal point or do they really use pipes that huge at paper processing plants? Anynobody 07:29, 22 July 2007 (UTC)

While I can't speak to paper plants, one way to create high pressure is to have a very large fan directed at a small pipe. So it could be that this opening is specific to the fan drive segment creating the large overpressure. Dragons flight 09:51, 22 July 2007 (UTC)

Yes, I believe you're right, it's likely 17.2 inches inner diameter. The "smoking gun" for me is that it said "the vacuum suction pulled his chest against it" and that "the victim was doubled over backwards and pulled 38 feet through the pipe by the vacuum". This means the pipe would need to be about the size of a man's chest. They apparently repeated the error everywhere they mentioned the pipe, which seems odd based on the level of detail in the rest of the article. I suspect that a spellchecker is to blame, which probably said "Did you mean 172 inch" when it found "17.2 inch". The editor then likely picked "Replace All" when they meant to pick "Skip All". Since the spellchecking was the last process in the checking process, they likely never read it after running the spellcheck, or would have spotted this obvious error. (Interesting that we a have serious human error in an article about a deadly human error.) StuRat 14:38, 22 July 2007 (UTC)

172 inches isn't the only number I'm suspicious of; I don't think I believe that "3,740 psi" figure, either. If the pipe is 17.2" in diameter, that's 400 tons of force on the end of it, or if (somehow) the pipe is 172", it's 40,000. With 400 tons on a 17" pipe, I don't think the poor guy would have been "stuck" long enough for his buddies to try to pull him off; I think he would have been sucked completely in in an instant.

3,740 psi is huge. You'd need special, small-diameter, thick-walled, high-pressure piping for it; there's no way you could sustain that kind of pressure in a 17" diameter pipe, unless it were constructed and machined like a submarine hull. —Steve Summit (talk) 15:22, 22 July 2007 (UTC)

Clearly the victim of this industrial accident was in the atmosphere on the outside of the building before he was pulled into the pipe, whatever its diameter. Therefore there could only have been 14.2 psi of "vacuum pressure" even if the other end of the pipe were connected to perfect vacuum. Air pressure pushed him into the pipe, rather than "vacuum pressure" pulling him into the pipe. It scares me that either a government or an industry would issue such an addled report. A 17.2 inch pipe is believable. The area is such that atmospheric pressure could apply 2200 pounds of force. The same phenomenon would apply as when a window of an airplane blows out at high altitude and a passenger gets sucked out (this happens less often than movies would imply). Why would they have attempted to replace the blower without shutting down the flow of air through the pipe? The whole story is senseless. Edison 21:20, 22 July 2007 (UTC)

Argh! You're right, of course. I was worried about the report's use of the perplexing term "positive-pressure vacuum pipe" also, but I didn't think it through far enough to remember that you can't have more than 14.2 psi of suction.

(I'm not sure I believe "17.2 inch", either -- would they really use that much precision? Wouldn't they just say "17 inch"?)

Addled and senseless, indeed. —Steve Summit (talk) 22:29, 22 July 2007 (UTC)

For 14.2 above, read 14.7. --Anon, July 23, 2007, 01:18 (UTC).

I've explored other case reports on the page, and get the impression that at some point in the late 1990's they finally started submitting these electronically. Which made me theorize earlier reports were transcribed. Would 374 psi be more reasonable for the pressure? Anynobody 23:25, 22 July 2007 (UTC)

No, it's still way too much. Most steam locomotives had boiler pressures less than that, and besides, as noted, 14.7 psi is the greatest possible suction. I wonder if they had something in mind with pounds? Let's see, the cross-section of a 17.2" pipe is pi*8.6^2 = 232.35 square inches... so it would take over 16 psi for the total pressure on one end to be 3,740 pounds. So that's not it.

Another thought: maybe the comma should be a decimal point. 3.74 psi. That still seems a lot for the stated purpose, but at least it's physically plausible and enough to suck someone in. But why would it be stated to such a high precision, if that was it?

--Anonymous, July 23, 01:18 (UTC).

People make dumb mistakes all the time, myself included if you've seen my user page. Reading not only this one, but several more senseless reports, this is simply what happens when people make dumb mistakes in a hazardous environment. I don't just mean the guy who got sucked to his death but whoever should have shut down the other blowers and appointed a safety manager. (I had no idea how dangerous it is to be a farmer, or the horribly disgusting fates possible.) Anynobody 23:41, 22 July 2007 (UTC)

Rather than attribute the death to a "dumb mistake" I would review the whole process for possible failures to follow standard OSHA safety procedures. The job as described was a literal deathtrap. There would normally be a job briefing, reviewing the possible dangers to avoid, with appropriate barriers, tagout procedures, safety harnesses, barriers, etc. I still do not understand why the intake of air through the 17 something pipe wasn't stopped while they were trying to mount a new blower over the opening. How did they get the old blower off the opening with that much pressure pulling it in? I just don;t see the need for all the alleged vacuum pressure to move wood chips into a machine, when a backyard leaf blower or vacuum cleaner would be adequate to move them, as soon as the air was moving at 3o miles per hour or so. Edison 15:07, 23 July 2007 (UTC)

Common knowledge in 2007 that would be insanely valuable in 1807.

If I -- a moderately-educated Australian adult of average intelligence -- woke up tomorrow to find I'd been warped to the year 1807, what knowledge of mine would be most valuable to the doctors, scholars, etc of the time? My first thoughts were of bacteria, psychotherapy and Franz Ferdinand's assassination. A Very Noisy Lolcat 07:35, 22 July 2007 (UTC)

Ones that spring to mind for me are advanced methods for producing steel, controlled steam locomotion (it was in its early stages in 1804-1810), internal combustion using stuff like diesel, electrical currents, vaccination methods, and the concept of the elevator. Inventing high grade steel for building materials, bio diesel, and an electrical generator would see the railways and business jump significantly ahead if started that early.  ALKIVAR™ ☢ 09:13, 22 July 2007 (UTC)

Ones that jump to my mind are the principles of electricity generation and that bacteria causes disease. Somewhat more esoteric, but highly practical would be dynamite, antibiotics and pasteurization. Dragons flight 09:33, 22 July 2007 (UTC)

This is a question I have thought about too and realised that unfortunately

• some things, I know can be done, but can't do them myself (e.g. making steel)
• some things I can do are useless without some other knowledge, that I lack (I could use transistors in a circuit, but I couldn't make them).

—Bromskloss 10:21, 22 July 2007 (UTC)

I'm not sure the 1807ers would be impressed by word of an event you claim will occur 107 years in the future. Algebraist 11:35, 22 July 2007 (UTC)

Photography and phonography would be pretty valuable, and at heart are both relatively simple - plus, bring them together and you've got talking cinema 120 years early! Laïka 12:22, 22 July 2007 (UTC)

Convincing them to look for Brownian Motion earlier, and experimentation with Uranium salts, in order to discover radioactivity, would have allowed remarkable advances in physics to have happened a hundred years earlier. Similarly, pretty much everything that became encapsulated in the Maxwell Equations could have been discovered and published in 1807. But in terms of common-place stuff, really simple things like hygiene - convincing people to wash their hands, boil their food and chlorinate their water - would have been hugely beneficial. Batmanand | Talk 13:56, 22 July 2007 (UTC)

Convincing people to be better stewards of the earth would be insanely valuable from 1807 to 2007.--138.29.51.251 14:00, 22 July 2007 (UTC)

When I consider this "time traveller problem" I realize that the main challenge would be to convince anyone to try your ideas. Hygiene for example was rejected by the experts time and again, and only tested and accepted after a long bitter battle. Remember that Semmelweis ended up in an insane asylum after a lifetime of failure at convincing doctors to wash hands. So, the most valuable tidbits in 1807 would be those things which would imediately make you fantastically wealthy. Having gotten rich, you could then fund all sorts of research and manufacturing based on 2007 knowledge, and those many who try to stop you would fail. In other words, you don't want to be a Ignaz Semmelweis who knows that surgeons should wash pus off their hands before the next surgery... and you don't want to be a Nikola Tesla whose amazing advances are sometimes accepted but usually ignored. Instead you want to be a Tom Edison who uses his income from ticker-tape machine sales to rapidly achieve any damn revolutionary idea he wants. --Wjbeaty 14:36, 22 July 2007 (UTC)

A knowledge of the Geology of Australia, particularly its gold deposits, would enable you to become insanely rich and thus fund your good works. DuncanHill 14:49, 22 July 2007 (UTC)

Or you could come up with some inventions that were expected in the 1810's. Inventions farther in the future likely wouldn't work due to lack of infrastructure. Airplanes, for example, wouldn't work in 1807 due to the lack of lightweight, powerful engines. StuRat 14:55, 22 July 2007 (UTC)

Makes sense, but then by definition, these inventions were about to come out anyway, so how valuable would introducing them a few years earlier (best case scenario) be? (Worst case scenario is getting attacked by irate 19th c. inventor for stealing their idea.) TresÁrboles 04:22, 24 July 2007 (UTC)

Psychotherapy would not be that valuable at that time. Most people would not believe it. It was an uphill struggle for Freud even a few decades later. You'd have a similarly difficult time convincing people about bacteria. Basically, in Kuhnian terms, you are talking about showing up with knowledge specific to a particular paradigm and trying to force it onto people who are not in any way prepared for accepting such a paradigm. What you want is someting that will easily assimilate into existing understanding; something that does not require extensive belief in certain abstract modes of thought (anything relating to things people cannot see is pretty tough to sell to people, even today, if they have not been taught to have faith in that matter of thinking); engineering advances would be the easiest in this respect, far easier than theoretical advances. Personally, I think the suggestion of dynamite was particular good (hell of a lot safer than traditional explosives at the time, requires no paradigm that people would find inaccessible in the early 19th century). The internal combustion engine could potentially work out as well — you'd need to develop an infrastructure which could take advantage of it but again the engineering and chemistry is not beyond their comprehension, just skill. With an effective knowledge of airplane design you could easily be quite valuable to any government, but you'd have to demonstrate it first. --24.147.86.187 16:48, 22 July 2007 (UTC)

Weaponry is another obvious one, for a man concerned only with getting rich. AK-47s, pump-action shotguns, semiautomatic pistols, napalm, plastic explosives, mustard gas, etc. --Kurt Shaped Box 17:23, 22 July 2007 (UTC)

While all of the above would be usefull, keep in mind that they're no immunity from sharpers or proficient confidence men and/or embezzlers. That said, Do you know anyone who was assassinated? The two dudes who saved that German Emperor from an anarchist got a dukedom each out of it (I think). If you happen to remember certain political trends, you could ride the waves and stay in office for years on end. 68.39.174.238 18:34, 22 July 2007 (UTC)

Copper wire was widely available in 1807, and the innovation of insulating it with cotton, then building telegraphs, electric generators and electric motors would be immediately feasible in 1807, if one had a high school physics understanding of these devices. A blacksmith or machinist of that era such as a gunmaker coud make the iron parts needed if you could describe them and provide drawings. A big 19th century electrical breakthrough was cutting the cost of a kilowatt hour of electricity by an order of magnitude or more by making it with a generator powered by a steam engine rather than zinc and copper plates in a battery. Next step: arc lighting. Then telephones. Then incandescent light bulbs (harder to get working with commercially useful lifetime and brightness than the aforementioned devices). Electric railways. Transformers and AC for long distance transmission of electricity. Household appliances. Then X-ray tubes and vacuum tubes, as soon as the light bulb technology is working, and the whole world of early 20th century electronics, up through radio. television and computers, but over a century earlier. Certainly a machine shop in 1807 could have built you phonographs and movie cameras and projectors if you could draw plans. I think you would have to be quite a specialist to know how to make transistors in 1807, much less integrated circuits, with the micro-etching and clean room crystal growing required.but knowing transistors are possible and the basic principles of doping semiconductors and biasing junctions should make it possible to kick start semiconductos solid state electronics if you developed a few hundred thousand dollars profit from the earlier ventures and could hire a research team. On the dark, side, certainly machine guns would be hugely valuable, as would land mines. A very high degree of specialized knowledge would be needed to get avation working. Even by the 1880's very silly things were written in the leading scientific journals about how airplanes of the future might work. Edison 20:57, 22 July 2007 (UTC)

Ah, any links regarding those silly airplane things? —Bromskloss 22:01, 22 July 2007 (UTC)

I could not find the articles I saw in Science in the 1880's issues. Indexing sometimes leaves much to be desired. But I found the steel balloon "aeroplane" with a vacuum inside, 1887 [8] , Aeropaedia from the Dublin Review [9](p 95) describes aeroplanes with screw propellors, proposed steam airplanes, and interesting acounts of balloon ascensions (1890). Steam airplanes are discussed (p302) in The Gentleman's Magazine (1888)[10] . If a time travellor built a working airplane in the 1880's or perhaps a few decades earlier, the notion would not have been novel to the educated person of that age. They would just have seen it as the culmination of research then in progress. Edison 14:52, 23 July 2007 (UTC)

If I could, I would bring a copy of Wikipedia! :-) —Bromskloss 22:01, 22 July 2007 (UTC)

That could be challenging without at least a computer and power. As I recall, we would fill something like 300 volumes. Dragons flight 22:28, 22 July 2007 (UTC)

If I found myself in the situation you describe I think I would keep very quiet about my ideas and knowledge. People of all ages seem to be very superstitious of people who have a great deal of strange information. The last thing I would want to do would be to give people the idea that I’m a sorcerer or demon. --S.dedalus 00:11, 23 July 2007 (UTC)

So, how was 1807? —Bromskloss 08:48, 23 July 2007 (UTC)

Lovely, thank you! Although having Bonaparte charging all over the place was slightly disconcerting. --S.dedalus 02:03, 24 July 2007 (UTC)

I suspect that most of these suggestions fail because most people from 2007 don't actually know how how most of the wonders we have work. To take the first few suggestion - how many of us could actually describe how these things work?

• advanced methods for producing steel - I have no clue.
• controlled steam locomotion - I have some approximate ideas, but I don't know the details.
• internal combustion using stuff like diesel - I understand the principles - but how to make the fuel?
• electrical currents - This is probably the one I could help most with - but even so, to make anything beyond an fascinating toy...tricky.
• vaccination methods - How the heck do you make a vaccine? No clue.
• the concept of the elevator - emergency fallback braking systems - and I'm not 100% sure how those work.

Sure we all have a vague idea - but outside of our own specialities, could we really offer much help? SteveBaker 01:27, 23 July 2007 (UTC)

You should read up on smallpox, anyone with access to dairy farms can make a crude version of that vaccine (though it was invented before 1807). As a physicist, I might fail metallurgy, but I bet I could get the others to work given enough time and period materials. Dragons flight 02:22, 23 July 2007 (UTC)

But if you wait a few more years, you could bring back the recipe for transparent aluminum. "Computer? Hello computer..."

Atlant 16:27, 23 July 2007 (UTC)

If you knew your history well, you could possibly turn the tide in the Naopleonic War to which side you chose if you could convince the right people.

You might be interested in this (fake) game show: "Phone Call to the 14th Century". You get 60 seconds to impart as much knowledge as you can. --TotoBaggins 18:48, 23 July 2007 (UTC)

Almost zero. The question isn't what you know is possible, but what can you build? Can you build an internal combustion engine and make the iron and steel necessary? Can you produce the kerosene? I can speculate about what might happen in 2107 but without the ability to actually build any of it, you might not be any different than anyone else. da Vinci proposed all sorts of things that he lacked the ability to build. But perhaps there is one thing you may know: boil your water. You may even be able to build a toilet as it is a simple mechanical device. --Tbeatty 20:12, 23 July 2007 (UTC)

Of course simply knowing that a given technology is possible is often all that is needed to spur innovation in the field. --S.dedalus 02:07, 24 July 2007 (UTC)

But see above the response by Wjbeaty, i.e. you will not be believed especially if you haven't the foggiest on how a particular technology actually works in any useful way. Remember, we are talking about the average person. TresÁrboles 04:22, 24 July 2007 (UTC)

It's a more interesting problem to consider the what the average person knows in detail and can demonstrate convincingly -- not much I'm afraid! (I include myself in this!)

Specifically for 1807 in the U.S. ... just brainstorming...

I know in the U.S., there's supposed to be a war with the U.K. in a few years. I don't know how that simple knowledge can help anything.

I know there's gold in California... yeah! Although... I'm not sure where to look (was it near Sacramento? Maybe an average Californian would fare better here). Likewise for the future gold rushes of the Yukon and Australia. For the Yukon, at least I know you can go from Skagway up across some insanely steep hill.. and then what?

I know about the airfoil, but I don't know that I could make anything other than a toy (if even that), and I'm sure they would already have flying toys.

Photography? Put some kind of chemicals on paper somehow and expose it to light just so, and ... never mind.

It's starting to look like there would be zero effect!

I 'm not sure if it would be different for a 2007 Australian person going back to 1807 Australia either. Maybe the average Australian knows where all the gold was? TresÁrboles 04:22, 24 July 2007 (UTC)

I would suggest sleeping from now on clutching a scientific encyclopedia, just incase of such an eventuality. (And hope that whatever transports you transports the encyclopedia with you). Capuchin 08:12, 24 July 2007 (UTC)

Spider identification

Hi, I took this shot of a spider in my appartment : [11] and I would have liked to identify its species so as to be able to upload it to commons and include it in relevant wikipedias. The size was about 2mm and it weaved a pretty impressive web of about 30cm diameter. I am living in Sweden. Any help is welcome. --Nattfodd 11:39, 22 July 2007 (UTC)

After looking at some galleries, it seems to be of the "long-jawed" kind, but I couldn't find the exact family. --Nattfodd 11:34, 22 July 2007 (UTC)

To summarize: 2mm long, north-european, brown colouring, probably long-jawed, weaves ~30cm webs. --Nattfodd 11:39, 22 July 2007 (UTC)

Turned out to be Uloborus walckenaerius. I found the answer on [12]. --Nattfodd 13:17, 22 July 2007 (UTC)

Wow that thing looks evil. Are there any better pictures of it? That one you found is in a strange posture. Or is it really like that? Capuchin 14:33, 23 July 2007 (UTC)

Tree rain

Is there a formal name for this phenomenon ? After a brief rain storm (during which time there may have been no rain under a large tree), the rain drops, which have been slowly falling from leaf to leaf, start to fall to the ground from under the tree, leading to a time when it is raining under large trees and nowhere else. This could also happen from dew after a wind gust. StuRat 16:10, 22 July 2007 (UTC)

yes, but I've forgotten what.

— Preceding unsigned comment added by 172.207.154.122 (talk • contribs) 20:24, 22 July 2007 (UTC)

I can't find this anywhere, the only word I can think of is "dripping". Sorry if this doesnt help. Maybe it would do better on the language desk. Capuchin 11:28, 23 July 2007 (UTC)

On the funnier side, we used to call this the "capacitor effect", imagining that the tree stores the "charges" and releases them later -- WikiCheng | Talk 05:16, 24 July 2007 (UTC)

Isn't it more like an inductor...? :p --antilived^{T | C | G} 06:08, 24 July 2007 (UTC)

Visible Insect With Large(st) Population

I am looking for a source on the worldwide population of an insect species which is very populous. I prefer an insect that is at least 2-3 mm long and is not eusocial. Really anything with a population higher than 10 billion would do.

I would also like to know the length of one generation of that insect.

The point of this is to provide an example of a species that would, on average, mutate every base pair in its genetic sequence in a relatively short period of time, given a mutation rate of 10^-10 to 10^-12. If you could find the population of an insect that has been observed to evolve either in nature or experimentally, that would be even better.

Thank you

I humbly suspect that most insect species have a population far greater than 10 billion. I know nothing of mutation rates and so on, but a classic example of an insect evolution observed "on-the-fly" is the Peppered moth. See Peppered moth evolution. Unfortunately it's much bigger (in it's adult phase) than the 2-3mm you specify, but it is a fascinating example. I'm sorry I can't give you a more specific answer - anyone else? Best regards, TreeKittens 02:04, 23 July 2007 (UTC)

A classic insect species for evolutionary and genetic studies is Drosophila melanogaster. It is usually 2-3mm in length, and I guess it's population to be utterly vast, but I have no evidence for this. It's generation time is about 2 weeks, depending on temperature etc. Hope this helps a little. Best regards TreeKittens 02:39, 23 July 2007 (UTC)

You could go for the plague locust. GB 02:44, 23 July 2007 (UTC)

You are aware I hope, that it is rather unlikely that a mutation in every base pair would be seen given that certain single point mutations will result in a change too critical for the resulting organism to survive? Nil Einne 12:40, 23 July 2007 (UTC)

Castor oil on eyelashes

Hi, I apply castor oil daily on my eyeleashes in order to make them thick. Is there any harm in doing that daily?? Thank you

If you are looking for medical advice, we can't answer you, as Wikipedia does not give medical advice. As for beauty tips, I have no idea, but perhaps someone else will. Dragons flight 20:36, 22 July 2007 (UTC)

Whether or not this is a request for medical advice, it can be answered without giving any! Our own article on castor oil discusses it's many uses in medical treatments and folk treatments. It was even commonly believed long ago to treat burns. The only adverse effect from castor oil, it appears, would come from consuming very large quantities of it (I have no idea what a large quantity would be for castor oil), but consuming anything in large enough quantities will kill you. Further, considering that castor oil is an ingredient in some foods, perfumes and even some modern medical treatments, I think you can make your own judgement on this. Someguy1221 21:42, 22 July 2007 (UTC)

Be aware that anything liquid applied to the eyelashes may regularly end up on the eyes and most perfumes, foods and medical treatments don't tend to end up on the eyes regularly. Nil Einne 12:34, 23 July 2007 (UTC)

I doubt that it hurts anything - but I'd be very surprised if it helped. Once a hair has sprouted from the follicle, it's dead material - more hair is added at the root - but the part of the hair you can see is just a dead thing. All of these shampoo adverts that talk about feeding and nourishing your hair are more 'sham' than shampoo. So the only things the olive oil could possibly be doing to 'thicken' your eyelashes would be to somehow cause the Keratin to swell up and thereby gain thickness (which sounds possible, I suppose) - or perhaps it might cause the follicle to grow a thicker hair (seems very unlikely to me). What I think you should do (for the good of all mankind) is to do a careful experiment. Put castor oil on your left eye lashes - and don't put any more on your right eyelashes. It takes 4 to 8 weeks for an eyelash to grow and then fall out - so if the oil is making a difference, it should be obvious within two months. If you can tell the difference between your left and right eyes after that amount of time then it works! Otherwise - not. To be really sure, you should ask other people (preferably those who don't know you) whether they can tell the difference - because you are bound to be a bit biassed. Please tell us what happens! SteveBaker 20:52, 23 July 2007 (UTC)

In some parts of south India, there is a practice of applying castor oil on the eyelids to get a 'cooling effect' (whatever it means). They also apply it on the eyelids if there is irritation in the eyes, as a home remedy. I am not sure if this really helps. I personally have felt that it makes you slightly drowsy, may be because you tend to close your eyes to get over that funny feeling after it is applied. I also agree with SteveBaker (to make the hair look thicker), because castor oil is also applied on the head -- WikiCheng | Talk 05:08, 24 July 2007 (UTC)

Binturongs

I was unable to track down the original reference that contains the information regarding the reproduction parameters in binturongs in the article. Could you please post those or direct me to the person that posted it? Thank you, Amoresco 21:05, 22 July 2007 (UTC)AMoresco

This information was in the original version of the article, as created by 64.63.221.115 (which IP has not edited for three years). The original article cited [13] and [14]. These source more-or-less corroborate the information given, though neither seems to give the estrus period. None of the currently listed references appear to give this information. Algebraist 14:14, 23 July 2007 (UTC)

Google gives this article on JSTOR: [15]. The abstract is kind enough to give all the facts. Algebraist 14:21, 23 July 2007 (UTC)

July 23

Hereditary talent?

(Following up on a question asked here.) Is there any evidence of a genetic link to artistic talent? Can a predisposition towards a specific field be hereditary? Thanks! --S.dedalus 00:03, 23 July 2007 (UTC)

For sufficiently varied choices of possible field, I'm sure it can be. Height and weight are genetically influenced and can affect who is more likely to succeed as various sorts of athletics (think basketball players, for example). For artistic talent, I don't know, but I wouldn't be surprised if there were a weak genetic association (coupled to a strong environmental/experience component). Dragons flight 00:08, 23 July 2007 (UTC)

Note that some conditions (not diseases !), like manic depressive disorder and homosexuality, may be both inherited and a cause of correlated with an "artistic temperment". StuRat 03:03, 23 July 2007 (UTC)

Be careful of the word "cause." correlated and causal are tricky things. --Tbeatty 03:06, 23 July 2007 (UTC)

Good point, I fixed it above. StuRat 03:22, 23 July 2007 (UTC)

Inherit... homosexuality... interesting theory there. Anyway, I'm not sure if it's nature or nurture, but I'm sure genetics have some effect on the brain and the way it forms and works, which could easily make someone like a certain thing their biological parents do, without even being exposed to them. At the same time though, artistic parents will probably expose children to art from a young age, so they will form their minds to that --L^augh! 03:57, 23 July 2007 (UTC)

Definitely you could say that there are hereditary traits which might be extremely useful for someone who happened to be disposed towards a certain career path and having these traits might even influence that person towards a particular career, playing to your strengths and all, but I don't know about being heriditarily "predisposed"; I doubt we will ever discover the astronaut or fireman gene. For example, there seems to be a genetic component to having absolute pitch, which could in turn be useful if one decided to become a musician. As to the first question, researchers have tried to answer it by searching for a "creative gene/s" or some evidence of heritability of creative talent, with apparently mixed results. This 1973 twin study, "failed to provide convincing evidence of a genetic component in creativity" [16]. However, this more recent '93 one (login needed for full article) presents a case that the genetic component of creativity has been overlooked and that, "creativity is an emergenic trait of moderate heritability" [17]. Even if creativity does have some genetic component, which seems likely in my opinion, environmental influences still must be accounted for, and this says nothing really about how the trait might be expressed; could just as easily end up with a creative janitor than with a brilliant artist. Interestingly the same study refrences a previous familial study which looked at a bunch of professions within families, finding that, "only judges seemed to aggregate within families," so maybe there is a "judge gene". -- Azi Like a Fox 05:08, 23 July 2007 (UTC)

Well, there's the remarkable Bach family. Clarityfiend 08:43, 23 July 2007 (UTC)

Some serial killers and the like seem to be creative too so any creativity could be expressed via such an outlet Nil Einne 12:30, 23 July 2007 (UTC)

The trouble with examples like the Bach family is that you can't separate nature from nurture. That is to say, you can't tell whether the younger Bach's inherited their talent from the older Bach's in their genes - or whether simply spending all of their youth amongst amazingly talented parents and other relatives caused them to learn those skills at an early age. To test the theory properly, you'd want to look at sons and daughters of musicians who had been separated from their parents at birth and who grew up with foster parents who were not musically inclined - and also at children of non-musicians who had been brought up by musically talented foster parents - and compare their abilities with offspring of musicians who lived with their parents. However, there is strong evidence that babies hear (and possibly even enjoy) music in the womb - so even separation at birth is not necessarily enough to show that there is a genetic basis. If I had to guess, I'd bet that musical ability would be a bit of both...but that's just a guess. Musical ability is composed of so many separate skills: good dexterity, an acute sense of pitch, a creative spark, possibly an interest in mathematics - it seems impossible that ALL of those would be genetically based - or that all of them would be as a result of nurture. SteveBaker 20:42, 23 July 2007 (UTC)

Chickenpox

Hi, does anyone know why chickenpox is more active in adults than in children? Thanks. —The preceding unsigned comment was added by 58.153.96.148 (talk • contribs) 07:00, 23 July 2007.

If you get chickenpox as a kid, you retain the antibodies in your system into adulthood - so any adult who had chickenpox as a child is effectively immune to the disease. Since it's a common childhood disease, very few adults succumb to it. The disease is mild in childhood - but much nastier for adults, so this is just as well! SteveBaker 11:11, 23 July 2007 (UTC)

I think the OP wanted to know why it is nastier in adults. Capuchin 11:27, 23 July 2007 (UTC)

Oops! I misread the question. Our chickenpox article offers some suggestions, it says that people with weak immune systems, the elderly and pregnant women are all at serious risk - I guess most children don't fall into that category. SteveBaker 12:45, 23 July 2007 (UTC)

I wouldn't think that a healthy adult would have a weaker immune system than a child. But chickenpox definately would affect them more. I'm curious to see if someone can explain it :) Capuchin 12:52, 23 July 2007 (UTC)

I've always heard that chickenpox is more serious for adults than children (which leads to the practice of sending children to visit those with chickenpox so they will get it when they are young). I asked three doctors in dermatology (because I felt it was in their field). Each one said it was far more severe in adults. I asked why and they didn't know. That led to a discussion of how severe it is and the conclusion is that they've always heard it was more severe, but none of them ever had an adult patient with chickenpox. -- Kainaw^(what?) 13:29, 23 July 2007 (UTC)

From my reading of the article, it appears that chickenpox is uncommon in adults, as most will have acquired immunity through childhood infection, however adults are liable to shingles which can be excruciatingly painful. DuncanHill 13:40, 23 July 2007 (UTC)

Philaethria dido page and butterfly identification

Hi, while checking "Uncategorised pages" on Commons, I came across Philaethria dido, which was blanked by user not logged in, it seems from the history that the image on the page was not a Philaethria dido (Scarce bamboo page) but a Siproeta stelenes (Malachite butterfly). I don't know the first thing about butterfly species, can someone more knowledgeable than me clear this up? (I will then either nominate page for deletion or not and/or upload the image again with a correct name). Thanks in advance. Deadstar 08:18, 23 July 2007 (UTC)

I think our anonymous editor has it right. Philaethria species lack the clearly visible spur on the rear wing and the entire forewing extend considerably farther, rather than having that lobe on the anterior. Go ahead and tag the page for deletion. Bendž|Ť 10:14, 23 July 2007 (UTC)

Thank you for your help! Deadstar 10:58, 24 July 2007 (UTC)

TECH CHALLENGE! !

Need source for 12 v Non-Lead acid Battery of the golf cart size ? This for some reason is very hard to find?

Need source for 12 v Non-Lead acid Battery of the golf cart size ? This for some reason is very hard to find?

If anyone can give me a concrete lead (ie verified phone or email or website ) of anyone or any company that can provide a Battery of the golf cart sizes (ie 10" long x 7" wide x 9"-11" tall) that is NOT- Lead Acid, I would really appreciate the information.

I am trying to test my patent www.triplebatterylife.com on golf carts more than I have in the past and need to use non-lead acid types. The maximum battery size is 10.3" long x 7.3" wide x 11.6" tall but can use somewhat smaller if necessary. GOD BLESS YOU FOR HELPING! ! P.S. 10.2"= 260mm, 7.1"= 180mm, 11.6"= 295mm TripleBatteryLife 18:08, 23 July 2007 (UTC)

Moving Energy

Is there any means of moving energy out of a gravitational field without gaining or losing any energy or potential energy? Philc 16:00, 23 July 2007 (UTC)

If you count Gravitational potential energy, you could do it by converting some form of energy besides kinetic into potential energy. If you don't (and you probably don't), I think you could do it by using gravitational potential energy holding the energy you're transporting apart i.e. compressing it under its own gravity, but you wouldn't get very far, and it's pretty useless. What I think you actually mean is impossible, because if you could do it you could drop the energy and create kinetic energy from nothing, disobeying the law of conservation of energy. If you could create energy, this would be trivial, since you could just create the energy used to move your energy. — Daniel 18:22, 23 July 2007 (UTC)

Double Pendulum

I was wondering how the time period of a double pendulum depends on the mass of the intermediate object and its distance from the main bob?

I suggest you read the article on Double pendulum. -- JSBillings 17:17, 23 July 2007 (UTC)

Beyond fairly small swings, a double pendulum is a classic example of a chaotic system - as such it doesn't even have anything you could reasonably describe as a period. SteveBaker 20:31, 23 July 2007 (UTC)

Rolling Up Projection Screen

I pulled down a projection screen and now I want to make it go back up. When I pull on it again, it goes down a bit and then will go back up that same amount (i.e. not rolling all the way up like I would expect). Has anyone encountered this before? What should I do? --82.171.103.231 17:38, 23 July 2007 (UTC)

WD40? But keep it away from the screen itself and any plastic parts. Wipe off any surplus.--Shantavira|^{feed me} 19:36, 23 July 2007 (UTC)

The screen is quite new. I'm not sure it needs WD40. I was wondering if there's some technique to getting it to go back up again. --82.171.103.231 19:55, 23 July 2007 (UTC)

Oh, those things always bugged me. I've found that you have to push up on the screen as it starts back up, which helps it start it's roll-up. -- JSBillings 21:21, 23 July 2007 (UTC)

We had a recent question about a stuck starter rope on a generator, and the same answer applies here: I have corrected this problem in the past by giving the screen a jerk and quickly releasing it or pushing it upwards (you might want to "escort it " up rather than releasing it completely, so it does not get going too fast. The screen, like a roller blind, must have a brake which keeps it from rolling up, but which is released by movement upward at some speed. Of course it could have a broken spring or other fault. Edison 21:41, 23 July 2007 (UTC)

Insulin

• why in humans insuline is less in non-vegetarians ?
• what are the reasons ?
• And what is the funtion of insuline in the body?
• why do docters suggest to not to take sugar content food or high carbohydrate food to diabetic patients?
• why weak or lean persons must take high carbohydrate food to become fat ?
• why fat persons must take protineious to become slim or lean or for there physical structure?

— Preceding unsigned comment added by 210.211.231.203 (talk • contribs) 19:44, 23 July 2007

Please understand that Wikipedia cannot provide any medical advice. I do not understand exactly what you are asking in the first 2 questions. Are you saying that vegetarians need more insulin or less insulin than non-vegetarians? The 6th question is also unclear. The answers to some of your questions can be found in Insulin. For the third question, see the section on "Regulatory action on blood glucose" in that article. Food is converted into glucose (a sugar) in the blood. Insulin allows the body's cells to use the sugar. You can find information related to the third and fourth questions in the insulin article and in the article about Diabetes mellitus, a disease in which carbohydrate metabolism is impaired. A diabetic person who eats an excess amount of sugary food or carbohydrate may develop blood sugar levels that are dangerously high. Under proper control, a wide variety of foods in moderation can be part of a diabetic diet. A doctor, nurse, dietician or diabetic educator can advise a diabetic on what kind of foods to eat, how much and how often, how to monitor blood sugar levels, how to correct high or low blood sugar levels, and the proper medications to take depending on the type of diabetes. See also Nutrition , Healthy diet and Dieting articles relevant to questions 4 and 5. If English is your second language, you may prefer the Wikipedia in "simple English" which has an article on Diabetes at [18]. Edison 20:34, 23 July 2007 (UTC)

I believe the last question is actually referring to the Atkins diet. The intake of protein does not make a fat person thin, but rather the complete lack of carbohydrate uptake causes their bodies to burn more fat than they normally would. 151.152.101.44 20:48, 23 July 2007 (UTC)

Sounds suspiciously like homework; I must remind you that Wikipedia does not do your homework, but if you have a specific part you're having trouble with (after you've done research and looked first), we'd be more than happy to help you. --71.98.4.68 00:02, 24 July 2007 (UTC)

This is not anyone's homework, as the answers to some of the questions are not straightforward. I am not sure what the first two questions mean and suspect the answer is likely to be different in a westernized culture and non-westernized culture. In a westernized culture, a vegetarian diet may still be high in carbohydrates, which provokes and requires more insulin secretion, while in non-westernized cultures, a vegetarian diet may be associated with reduced body fat and greater insulin sensitivity. People with diabetes often stay healthier if they reduce carbohydrate intake somewhat, and especially if they avoid eating much sugar, because both types of foods are likely to raise their blood sugar levels further. Insulin promotes fat storage, so it is often easier to gain weight with a high carbohydrate diet and easier to lose fat with a lower carbohydrate diet. alteripse 02:54, 24 July 2007 (UTC)

Acoustic inertance of a long thin slit in a wall of negligible thickness

Im trying to find the inertance of a long thin slit in a thin walled cavity for a speaker deign problem. Inertance is m/S^2 (where S is the area and m is the mass of the air) but 'm' cannot be defined as there is negligible wall thickness. Or should I also use an end correction for my slit? If so, what is the end correction for a slit? Is it the same as for a cylindrical tube?--SpectrumAnalyser 20:42, 23 July 2007 (UTC)

Is Teflon safe to cook with?

I read the section of 'Teflon' concerned with safety, and I don't know what's true and what isn't. All the sources cited are either studies funded by DuPont or what looks like paranoid woo. (Previously, tuberose.com was used as a source; note the bits about "jagged, scary-looking chunks of synthetic chemicals that have no place in the human body" and the expression of surprise at discovering that using metal implements on nonstick cookware is destructive.) I was hoping for some kind of objective answer here, and I've been unsuccessful at finding anything. It seems ridiculous that there's no good study of the safety of such a widely-used chemical; it also strikes me as odd that there are "many published cases of health effects" related to the use of nonstick cookware, none of which I've been able to dig up. It's, of course, quite possible that my research skills are rusty, and so I come to you, the reference desk, because I'm honestly very, very confused about where the truth lies. grendel|khan 22:02, 23 July 2007 (UTC)

This is one of "those" topics where it's very hard to sort the facts from the paranoid woo, but Teflon has been around long enough that one would think that if it were really trouble, we'd have some pretty strong indications by now. On the other hand, it does seem clear that when it's overheated, its decomposition vapors are bad. And the perfluorooctanoic acid precursor/relative is bad. But the finished product, used properly, seems okay.

Atlant 01:00, 24 July 2007 (UTC)

As Atlant says, it's a controversial topic. If the Wikipedia editors who've worked hard at providing a nicely balanced and accurate presentation at the Teflon article haven't managed to give you quite the answer you're looking for, I'm afraid we duffers here at the Reference Desk aren't likely to be able to, either. (My own belief, for what it's worth, is that Teflon is metabolically a rock and is perfectly safe to ingest in small quantities.) —Steve Summit (talk) 01:08, 24 July 2007 (UTC)

Serious side question, what do people know about the risks posed by decomposing Teflon at 400 C? Dragons flight 01:11, 24 July 2007 (UTC)

What food doesn't turn carcinogenic at 400°C for prolonged period of time anyway? --antilived^{T | C | G} 06:03, 24 July 2007 (UTC)

Most food isn't packed full of flourine... It's a serious question because I've been in the room with Teflon that was baking off and still have the results (which will never be used for food again). Dragons flight 06:24, 24 July 2007 (UTC)

I wrote a Teflon flu stub, which has since been deleted and made into a redirect to polymer fume fever. StuRat 07:15, 24 July 2007 (UTC)

Wikipedia cannot give cooking advice. Please consult your food care professional if you have any concerns. --Trovatore 07:39, 1 April 2525 (UTC)

July 24

Diabetes

Hi, I know that hyperglycemia is a symptom of diabetes, what about hypoglycemia, is it also classified as diabetes, or is there another disease for it? Thanks. 58.153.97.9 01:42, 24 July 2007 (UTC)

Hypoglycemia#Causes. Someguy1221 02:45, 24 July 2007 (UTC)

Hyperglycemia is the central manifestation of diabetes mellitus, the core pathophysiological condition that distinguishes diabetes from other diseases. Hypoglycemia is a common complication of treatment of diabetes, because insulin and other agents that lower the blood sugar occasionally "overshoot" and bring the blood glucose too low. Whether hypoglycemia is ever a prodromal manifestation of diabetes is unsettled; a few case reports suggest it, but it is uncommon and difficult to prove that the hypoglycemia was an integral part of the process of developing either type 1 diabetes or type 2 diabetes. You might have found the answers in the articles linked, but I suppose asking here is easier. alteripse 02:45, 24 July 2007 (UTC)

Transsexual

I know that I am not suppose to ask any porno questions, but I want to know that is there a slang for a transsexual man who doesn't have a penis? because his female counterpart is called a shemale because she has a penis.—The preceding unsigned comment was added by 76.64.55.150 (talk • contribs) 02:25, 24 July 2007 (UTC)

Your question is legitimate and not "porno", According to the Transwoman article the term you are looking for may be post-op. -hydnjo talk 04:34, 24 July 2007 (UTC)

effect of acid on plant life!

We had many plants around us in our university...it was merely like a forest with grasses, weeds, herbs, shrubs & trees! & everyday atleast a hundred (or even more) people urinate randomly around those plants (all varities)..now i wonder why not even a single plant is getting effected with such continuous urination. We know that human urine was highly acidic& it should definitely affect the plants..but not even a single grass or any big tree is getting affected..can u explain me why? Temuzion 04:05, 24 July 2007 (UTC)

Check out some of these links. - hydnjo talk 04:43, 24 July 2007 (UTC)

Most plants prefer a slightly acid environment, preferably to alkaline anyhow. The worst thing urine could do to a plant is if it gets on the leaves directly, eutrophication will allow mildew will grow on them. Bendž|Ť 08:44, 24 July 2007 (UTC)

extraction of hydrogen from methane

i want tht topic —The preceding unsigned comment was added by Deepikavoona (talk • contribs) 05:43, 24 July 2007 (UTC)

Go read the articles on hydrogen and methane, both of which discuss the methane → hydrogen conversion. DMacks 06:05, 24 July 2007 (UTC)

(edit conflict)

Here is something for you: In extremely high temperatures methane will decompose into Hydrogen and Carbon gas. This happens in stars. When methane burns in oxygen it will form carbon monoxide, steam and hydrogen for a short period, before the hyrdogen is burned up. Steam reforming reacts methane with steam to produce carbon monoxide and hydrogen. Nickel is used as a catalyst. The water gas shift reaction can covert some more of that carbon monoxide to Hydrogen. GB 06:13, 24 July 2007 (UTC)

Do Electrons in an atom slow down in lower temperatures?

Will electrons in orbit in an atom slow down when the temperature is decreased? (I'm guessing no)

--wj32 ^{talk | contribs} 08:11, 24 July 2007 (UTC)

No, not really. Temperature is approximated by the kinetic energy of a group of atoms(/molecules). You have to remember that the electrons don't really orbit, they are defined by a fuzzy probability cloud, they don't really move in a classical way like atoms do (mostly). You can knock electrons to a higher energy level through providing heat energy, but they're normally unstable and will re-emit back down to a lower energy level. I assume that you haven't studied quantum mechanics yet, so i'll leave it at that. Capuchin 08:15, 24 July 2007 (UTC)

Thanks. Also, what force makes electrons stay in different energy levels? I mean, just because theres protons and neutrons in the center doesn't mean electrons should stay in orbit... Protons attract electrons, but why don't the electrons stick to the protons? --wj32 ^{talk | contribs} 08:34, 24 July 2007 (UTC)

I don't think there's any way to explain that without invoking quantum mechanics. In classical mechanics, the electron should radiate energy in the form of electromagnetic waves and continue to get closer and closer to the nucleus. The amount of energy radiated is infinite because the integral of 1/r² diverges as r tends to 0. This is obviously unphysical.

In quantum mechanics, the ground state is the lowest energy state, and the electron cannot decrease its energy by getting closer to the nucleus. If the wavefunction got smaller, it would have to be more strongly curved, and since the kinetic energy is directly related to the wavefunction, it would go up. The electron cannot get closer to the nucleus without vibrating faster, and the energy cost of the vibration exceeds the potential energy. The ground state wavefunction is a perfect balance between potential energy (distance from the nucleus) and kinetic energy (quantum fluctuation).

Note that this "vibration" can never be directly observed: it's not that the electron moves to one side and then the other; it's that it's always vibrating in all directions in a spherically symmetric manner. —Keenan Pepper 09:14, 24 July 2007 (UTC)

This is why I was having trouble answering. Unless you have studied quantum mechanics, it's very difficult to see these things in a way that is not newtonian motion. When you're talking about electrons, you have to drop most of the assumptions (and lies-to-children) that you have been taught. Electrons are too small to be described by Newton's laws. Capuchin 09:18, 24 July 2007 (UTC)

Girls vs Boys

Is there any reason for girls (as a trend) to prefer pink while boys prefer blue? Just curious, thanks!

There are extensive discussion on this in Talk:Pink and Talk:Blue. I guess it's a form of stereotyping. Lanfear's Bane

Tusks

Why do elephants have tusks? What purpose do they serve?

Have you read the Tusks section of our Elephant article? — Matt Eason ^{(Talk • Contribs)} 12:02, 24 July 2007 (UTC)

Blood serum vs blood plasma

I am confused with the 2 terms as I don't see their difference, even after I've read the related articles. Thanks.

It says on the disambiguation page serum that blood serum is "Blood plasma, with clotting factors removed". This would seem to explain the difference quite well. The clotting factors being Fibrinogen. Capuchin 12:24, 24 July 2007 (UTC)

RepHresh

Does anyone know what are the ingredients in the product RepHresh? How does it normalize the pH balance in the vagina? --WonderFran 12:39, 24 July 2007 (UTC)