Wikipedia:Reference desk/Archives/Science/2007 February 9

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February 9[edit]

Hottest Temp...[edit]

Amigo of mine said that it hasnt been above 100 Farenhiet in the U.S. in February of '07, is this true? I just read a NASA article that said Death Valley, CA, USA is the hottest place on the Earth...for real?

Cheers, 02:02, 9 February 2007 (UTC)moe.ron

Since it's barely a week into February, and February being in the winter, I highly doubt the U.S. has had areas reaching 100 F, which is already not too common during the summer. But yes, I believe Death Valley is the hottest place on earth. --Wirbelwindヴィルヴェルヴィント (talk) 02:11, 9 February 2007 (UTC)
I always thought the Atacama Desert in Chile had the highest recorded temperature, near 130 degrees F. I should check my numbers, though... Nimur 02:56, 9 February 2007 (UTC)

Google says El Azizia in Libya, hottest temp was recorded in 1922. --Peta 03:51, 9 February 2007 (UTC)

The Atacama Desert in Chile is the hottest desert in the world, Death Valley is the hottest in the United States and El Aziza is where the hottest temperature was ever recorded (some say Aswan), the top spots for that are all in the Sahara somewhere. [Mαc Δαvιs] X (How's my driving?) ❖ 04:33, 9 February 2007 (UTC)
also check out Marble Bar, claimed to be the hottest town. It is located in Australia. But the most extreme here is 119.8F. Its consistently hot for months at a time. GB 06:24, 9 February 2007 (UTC)
No, I don't think so. The hottest place on Earth is likely the Sahara Desert, in northern Africa, the hottest temperature on Earth being recorded there. In the summer temperatures can reach 40°C in some areas almost every year. Hope this helps. AstroHurricane001(Talk+Contribs+Ubx) 19:39, 17 February 2007 (UTC)

Sound coming from tv to computer speakers[edit]

I've noticed that sometimes when I put my hand against my tv screen, which is right by my computer speakers, a sound comes out of my computer speakers. They aren't hooked up in any way so I was wondering how this could be. Thanks. Imaninjapiratetalk to me 02:22, 9 February 2007 (UTC)

My guess is that you get a lot of static 'sparkles' when you put your hand on a CRT screen in dry humidity. This could be picked up by the speaker wires, especially those amplifying ones, that are powered on, but not connected directly to a computer. --Zeizmic 02:51, 9 February 2007 (UTC)
Ah, I see, I do feel those static sparkles. Thanks for the response! Imaninjapiratetalk to me 03:10, 9 February 2007 (UTC)
Perhaps it's Electronic voice phenomenon? :) Nimur 05:30, 9 February 2007 (UTC)
Ahhhhhhh! :-O! Imaninjapiratetalk to me 22:53, 10 February 2007 (UTC)

Pressure treated lumber splinter under the skin...?[edit]

I know that pressure treated lumber has arsenic and copper compounds, etc. to prevent insects from attacking the wood. So what happens if one gets a splinter when carrying pressure treated lumber? Is there enough toxic chemicals in a splinter if left under the skin to get into the blood stream and cause death? -- Barringa 03:32, 9 February 2007 (UTC)

Not cause death, no. If the preservatives were that toxic to humans, you wouldn't be able to buy the wood just anywhere, and you wouldn't carry it bare-handed ever, and you wouldn't build decks out of it that you would then walk on barefoot or casually eat spilled hamburgers off of.
With that said, though, the chemicals are pretty nasty. I've noticed that if I saw pressure-treated wood, I feel a raspy sensation in my throat that I certainly don't get when sawing regular wood. (Yes, I should probably wear a dust mask more often.)
I don't think I've heard of splinters from treated wood being hazardous. (If anything the chemicals might help kill the germs that might otherwise infect the puncture wound.) But I'd certainly pay extra attention to a nasty puncture from treated lumber, and seek medical attention if my skin turned a funny color or anything. —Steve Summit (talk) 03:49, 9 February 2007 (UTC)
Wikipedia is not qualified to give medical advice - this includes diagnosing if you are at risk from a given amount of a potentially dangerous compound. Wikipedia:Medical disclaimer. Usually, most locations have a free poison control hotline for things which aren't quite 9-1-1 emergencies. Failing that, you would do well to call your doctor's office or HMO, and speak with a nurse there. -- 20:46, 10 February 2007 (UTC)

Electronic voice phenomenon[edit]

Hello, I think I have stumbled upon an absurd situation at this article. I have tried to place a tag alerting editors that content policies may not be followed there. There is original research, and non-objectivity. For example, the article divides points of view into "paranormal" and "non-paranormal." The scientific point of view is referred to as "non-paranormal," rather than scientific. Also, scientists are referred to as "skeptics," rather than scientists, as if believing in extraterrestrials communicating via magnetic tape were the majority viewpoint, and there were some minority "skeptics." I believe it is the other way around, there is a minority which believes in this, and the scientific majority does not. Scientists are scientists, not skeptics and non-paranormals. Also, the article contains a self-published purported recording of a paranormal voice, which is original research, I believe, since it was recorded and published on a website by the same people, not by a reliable third party. an editor keeps removing the tag I have placed. I am not sure what to do.-MsHyde 05:12, 9 February 2007 (UTC)

Yikes. At least posting it here will get more eyes on it, and hopefully that will help build a majority consensus. Nimur 05:19, 9 February 2007 (UTC)
I've read through the article. They make very few falsifiable claims, so I don't know if you can truly cite them on inaccuracy (though it's certainly not a science article). I guess it's difficult to accept, but people will believe what they wish to believe. In its present form, the article clearly states that there are alternative, simpler explanations than the "supernatural" - but if people choose to conclude otherwise, no amount of proof can convince them. Nimur 05:28, 9 February 2007 (UTC)
It's fascinating how one paranormal wiki-page can lead me onto a goose chase of paranormal stuff. If EVP infuriates you, check out Shadow people - there's all KINDS of awful science there! Anyway, it looks like there's some consistency among these pages. They all list Paranormal vs. Non-Paranormal explanations. Honestly, I'm content with that level of consistency. Though you and I may choose to believe the scientific explanation, assume good faith and let people think what they will. It doesn't harm us to allow them to live in ignorance. Plus it makes for entertaining television. Nimur 05:33, 9 February 2007 (UTC)
Yes, but this is an encyclopedia. Neutrality is important. The original research policy looks like it was developed precisely to keep crackpot theories in check. That is fine if people want to privately believe that science is "non paranormal," but it is not appropriate to label it that. The majority definition of science is science, not "non paranormal." And the audio recording is, frankly, ridiculous. It was published on a website by the same people who recorded it. It could be a recording of their vacuum cleaner.-MsHyde 06:33, 9 February 2007 (UTC)
The original research policy also keeps you from using your own beliefs to determine the validity of an article. However bunk EVP may be, it is notable. The article, in its current state, makes no claims as to its validity, and nothing about the article is the least bit against Wikipedia's policies. Furthermore, just to cover the complaints, skeptics is a perfectly appropriate term. By definition, those who do not believe in something are skeptical of it. Finally, the audio recording is also fine. Regardless of how valid it may be, it is still an example of EVP. – Someguy0830 (T | C) 06:41, 9 February 2007 (UTC)
It is claimed to be an example of EVP, but not by a reliable source. It is the original research of two people who make money off of EVP, and self-published it on their website. Skeptics is not the appropraite term for scientists. Per due weight, even in an article about something, an extreme minority view should be represented as such. That means, science is the majority view, not the "skeptical" view, or "non-paranormal" view. The article as written is heavily slanted towards the view that EVP exists.-MsHyde 08:38, 9 February 2007 (UTC)
It is not. The thing is a blow by blow history and a possible causes section, with equal weight given to both. The article does not exist to disprove or prove EVP. It only exists to detail the phenomenon. – Someguy0830 (T | C) 09:08, 9 February 2007 (UTC)
I haven't read the EVP article (if for no other reason than that I don't have time this morning for "wild goose chase of paranormal stuff", as Nimur so nicely put it), but I'm prepared to believe that the article needs work. Thanks, MsHyde, for trying to do something about it. With that said, this Reference Desk probably isn't the best place to figure out how to better apply Wikipedia's NPOV policy to that article -- I'd also try its talk page and the Village Pump. —Steve Summit (talk) 13:24, 9 February 2007 (UTC)
I see that the proponents from the AA-EVP are pushing POV in the article again, as they stand to gain credibility for the organization and its beliefs from a Wikipedia article that supports the existence of EVP. The content of the article has been carefully limited by AA-EVP proponents in order to "present the best face" to the public, e.g. the varied beliefs and practices of hundreds of independent "ghost hunters" with regard to EVP has been left out, and only scientific-sounding research has been left in. I admit that these are rather vague generalized complaints, so if you go to Arbcom, you'll need to cite specific text which you dispute and concrete reasons which back it up according to WP policy. --- LuckyLouie 03:18, 10 February 2007 (UTC)
Any unpublished recording is definitely original research, and should not be considered as a source to support the claimed EVP. I could make a tape with mysterious voices on it very easily. To be used in an article, it would need to be published by a "reliaable source," and in a scientific dispute it should have been published in a respected peer reviewed journal. Questionable evidence should not be used to create a Wikipedia article which can then be cited as "proof" that the claims are valid. No home-made flying saucer photos, no personal diaries of time travel or UFO abduction, no claims that one had a dream forecasting some publicized disaster. No claims that one is Elvis's love child. No personal bigfoot sitings. No claims of having invented a miracle cancer cure or perpetual motion machine. Edison 15:59, 9 February 2007 (UTC)

immune system[edit]

Hello, i was just wondering when "B cells" inside our body is trying to fight off "invader cells" and there are also body cells there aswell how the the "B cell" tell teh difference beetween teh two other cells?

thankyou very much, i really apreciate it :D. 05:50, 9 February 2007 (UTC)

Our articles on Adaptive immune system and B cell answers your question. Rockpocket 06:46, 9 February 2007 (UTC)
I agree with Rockpocket that the articles linked to answer your question. However, they contain a lot of information if you know little about this beforehand, so here's a simplified version:
In most circumstances, it isn't the B-cells that tell the difference between self and non-self. It's the helper T cells. Both B and T cells have antigen-specific receptors that are generated randomly by somatic DNA recombination when the cells develop. One clone of T or B cells has one receptor, which recognizes one single antigen only. B cell receptors (≈immunoglobulin) can arise that recognize just about anything. T cell receptors, however, are designed to recognize major histocompatibility complex (MHC) molecules, which are cell surface molecules found on most cells of the body, and which always have a short peptide bound. The peptide is put there when the MHC molecule is assembled, before it goes to the cell membrane, and may be derived from either the degradation of one of the cell's own proteins, or from a virus, or from bacterial proteins that the cell has "eaten". Because of the random process that creates the receptors, auto-reactive receptors are generated both for T and B cells. Auto-reactive T cells, however, are eliminated in the thymus, and never reach maturity. The T cells that reach maturity are those that recognize your own MHC molecules, with a foreign peptide in them. Those B cells that happen to be reactive towards the same foreign protein as a given helper T cell clone, will have MHC molecules that are loaded with peptides derived from that foreign protein, because recycling of their B cell receptors ensures that some of the material is internalized, degraded, and displayed on their surface bound to MHC molecules. When a helper T cell encounters a B cell with the right combination of MHC molecules and peptides, it signals to the B cell that now is the time to launch an attack against the invader. --NorwegianBlue talk 13:43, 9 February 2007 (UTC)


how can a eutrophied lake be rescued —Preceding unsigned comment added by Bates g (talkcontribs)

Welcome to Wikipedia. You can easily look up this topic yourself. Please see eutrophication. For future questions, try using the search box at the top left of the screen. It's much quicker, and you will probably find a clearer answer. If you still don't understand, add a further question below by clicking the "edit" button to the right of your question title. --Shantavira 13:02, 9 February 2007 (UTC)

There is at least one "solution" that is worse than the problem. Several waterways in the Unites States that used to be eutrophied are now beautifully clear because of the accidental indroduction of the zebra mussel. -Arch dude 02:11, 10 February 2007 (UTC)

Hmmm. Just read the zebra mussel article. Would one solution to the problem not be to harvest the mussels for food (human or animal) or render them down into fertilizer? --Kurt Shaped Box 02:25, 10 February 2007 (UTC)
Zebra mussels are problematic for a number of reasons. One is that they clog inflow pipes for power plants and water treatment plants. Since they are in the tubes, they are difficult to manage. Another problem is that they settle on hard substrates. In many North American soft-substrate lakes that means that they settle on, and overgrow, native mussels. Since native North American mussels are in a lot of trouble (and North America is a centre of diversity for Unionid mussels) there are major risks to zebra mussel introductions. Guettarda 21:13, 10 February 2007 (UTC)

Heat Sink Formulae[edit]

Given the fin surface temperature of 68 degree Celsius and resistor temperature of 100 degree Celsius what would be the heat sink design?? This is in context of a convection cooled RF Load of 60W operating at 1 GHz frequency. What would be the fin height, no. of fins and cross sectional area of fin??? The base of the heat sink is at a temperature of 87 degree celsius?

Are you the same person who was asking this before? I suspect you're not going to get the precise, detailed answer you need here. You might want to try asking your instructor, or hiring a knowledgeable consultant, depending on the context of your problem. Good luck! —Steve Summit (talk) 13:28, 9 February 2007 (UTC)
Among other factors you'll need to consider: What fluid is the heat sink immersed in, at what temperature does the fluid enter the system, is the fluid freely convecting or being forced to flow, how much turbulence occurs at the heat sink fins/pins, etc.
Atlant 14:14, 9 February 2007 (UTC)
Before didn't you say 600 watts? It would take a while to heat up say a gallon of oil or silicone fluid with 60 watts of heat. Engineers who miss decimal points tend to design things which do not function up to expectation. I seriously mean this. The bridge falls down or the plane crashes. I had a professor who would take half off an answer for an "oops error' on that ground. Again, seriously consider a cooling fan, and look at a space heater as a model. You must consider the ambient temperature and the air flow. Perhaps a fan could blow room air in at the bottom, so the fan is spared the heat, and the hot air come out at the top or side. You need to spare your cable and connectors from the heat. I still suggest a thermometer or thermocouple (with a design which will not be affected by the RF emission) to make sure the oil is not too hot, and a design which makes sure the resistor is not partially out of the oil. Transformers sometimes have a float switch inside ot a level indictor with a float, or in the old days, a sight glass like on a big coffee pot. You must also allow for the expansion of the oil, so you do not have a pressure buildup which ruptures the can. Detailed design goes beyoond what I or most people here have attempted. There are probably specialized programs to be used with graphical mathematical analysis programs for such heat flow calculations. Good luck. Edison 15:50, 9 February 2007 (UTC)

Thanks... I had said 600 W before but my requirement got revised to 60W... The ambient temp. would be 35-40 degree celsius and the fluid would be at that temperature too. The heat sink isn't immersed in anything and I would like to know if a fan would be required to dissipate the heat. I am considering using a resistor of 15 W rating and design the heat sink such that the resistor can absorb 60 W and dissipate without the heatsink(case/body) getting heated up more that 35 degrees in addition to the ambient temp...

So if your heatsink is not immersed in anything, maybe you're trying to make a black body radiator instead? (air is a thing) :p Also, the requirement of a fan depends on the size of your heatsink, whose heat resistance must be lower than 0.58 °C/W, and probably lower to take into account of other resistance like junction between your resistor and things like that. --antilivedT | C | G 06:42, 10 February 2007 (UTC)
Maybe you should search for parts instead of trying to design from scratch. Most heat-sink data sheets describe their operating point and heat capacity. 17:27, 19 February 2007 (UTC)

Headline textItalic text[edit]

Uranium refinement[edit]

According to the Uranium article, the production of uranium metal from uranium ore involves using uranium halides. Are there any simple ( but not necessary quick or efficient ) ways to produce uranium metal direct from ore ( such as using electrolysis or reducing agents ? Robmods 11:17, 9 February 2007 (UTC)

The ore can be treated with nitric acid or sulphuric acid. Then treated with ammonia, producing ammonium diuranate. When heated in air you get U3O8 The metal can be made by roasting U3O8 with sugar charcoal in an electric furnace. But watch out as it burns at 180° C. There is no need to use halides in this process. The idea is to separate chromium and molybdenum from the mix. Probably UF6 is required to do isotope separation, as it is a gas at fairly low temperatures.

From Inorganic Chemistry by T Martin Lowry, McMillan 1922. GB 07:27, 10 February 2007 (UTC)

How many protons, neutrons and electrons is in the average in human body[edit]

Hallo, I´d need to know, how many protons, neutrons and electrons is on the average in human body? How many is it for one cell? Thank you

You can make a rough estimate from four assumptions.
  1. Essentially all of the mass in your body comes from protons and neutrons (electrons are so light that their contribution is negligible for now; the masses of each particle are in the linked articles).
  2. Your body will contain roughly equal numbers of protons and neutrons, as the most common elements and isotopes (oxygen-16 and carbon-12) in your body contain equal numbers of protons and neutrons. (For bonus points you can account for the contribution due to hydrogen, which mostly contains one proton and no neutrons; these tables have the relative contributions of each element to the body's weight: [1], [2]).
  3. The number of electrons is equal to the number of protons—your body has no net charge.
  4. Finally, the human body contains roughly 100 trillion cells: see Cell (biology).
That should get you started. TenOfAllTrades(talk) 16:25, 9 February 2007 (UTC)
Don't even need to know how many cells...just how much total mass. DMacks 19:09, 9 February 2007 (UTC)
He also wants to know how many are in a single cell... --Neo 19:13, 9 February 2007 (UTC)
Ah yeah. DMacks, Friday-afternoon moron.

So that would be slightly more than 8x10^26 of each per kg:)Hidden secret 7 19:48, 9 February 2007 (UTC)

So how many atoms is that:]HS7

Fundamental Tissues[edit]

I am aware that there are the four primary tissues- neural, connective, epithelial and muscle- and that most(all?) tissues fall under these, but where would specific tissues of the organ fit, say liver or kidney...

It depends. Most organs contain a mix of the four 'classical' tissue types. Taking the heart as an example, it contains:
  • Neural tissue: The heart is innervated by (among others) the vagus nerve.
  • Connective tissue: The heart circulates blood, the pericardial sac is lubricated by adipose tissue. The fibrous pericardium and epicardium are both mostly connective tissue.
  • Epithelial tissue: The endothelial cells which line the blood vessels of the heart are epithelial tissue.
  • Muscle: The heart is mostly muscle.
In other words, you have to look at the organ in detail. TenOfAllTrades(talk) 16:37, 9 February 2007 (UTC)
What about say specific cells like hepatocytes, kupffer cells etc. Do they have to fit into the 'primary' tissue classification? (cells do make up the tissue after all- they only seem to fit into the connective tissue group...)
In the histological schematic you are talking about, hepatocytes are endothelial, they form sheets with clear lumina (is that the plural for lumen?); and kupffer cells are connective tissue (they are really just special macrophages). Remember that connective tissue falls into two categories, mobile (like plasma cells, mast cells etc.) and resident (fibroblasts, adipocytes, etc.). As stated above, these cell types interact metabolically and structurally to make the tissues we call organs. I can't personally think of any epithelial cells which appear without nearby connective tissue, nor muscle which occurs without neural tissue either connected (as with skeletal muscle) or somewhat nearby (though with the muscular conduction in the heart, cardiac tissue is something of an exception).tucker/rekcut 22:51, 9 February 2007 (UTC)

Goldfish floating upside down[edit]

Ever since I got a couple of goldfish (the typical big-eyed kind that you can get in any pet store), one of them has spent a lot of time floating upside down at the top of the water. The first time I saw it do it, I thought it was dead. But a few minutes later it was swimming around fine. I've had it now for about six months and nearly every day it does this playing-dead upside down thing. Sometimes it even swims around the tank upside down for several minutes. Is this unusual behavior? Is my fish sick? Or is it just a weird fish? Deli nk 15:31, 9 February 2007 (UTC)

Try googling swim bladder problems in goldfish. Apparently fancy goldfish are prone to problems like that. Guettarda 16:13, 9 February 2007 (UTC)
FYI, you probably have comets; they're a very common kind of "fish store" goldfish. And yes, it's quite uncommon for a healthy fish to be completely inverted, although they certainly do momentary headstands, tailstands, and the like when feeding.
Atlant 17:05, 9 February 2007 (UTC)

quick question about the comet gold fish

whats the max temprature range they can survive in Maverick423 18:44, 9 February 2007 (UTC)

There seems to be quite a bit of info out there on swim bladder problems, as Guettarda suggested. After reading a bit, it's pretty clear that's the problem. Thanks all! Deli nk 19:16, 9 February 2007 (UTC)

how much force does it take to propel a body the size of (lets make it easier: Pluto)[edit]

how much force to propel an object of this size???...or to change its current direction of motion??? and could humans ever achieve such a thing as propelling such large objects...??? how much does it take to fight the suns gravity and drive such a large object out of the solar system???...can the gravity of other planets be used to make it easier?? yet what would the initial force have to be like???...perhaps its easier to work with objects out near pluto???...could pluto and another object out that way be set into orbit around eachother on course heading out of the solar system???...(from a biologist)(its been a while since college physics class someone else can answer this quickly)...Benjiwolf 19:10, 9 February 2007 (UTC)

F=ma, therefore the force needed to move an object would be the mass of the object, (in kg) multiplied by its acceleration, which is the same as the combined forces of gravity acting on it (in m/s^2):) Gravity varies with the square of distance from an object, so away from a planets surface, most of it would come from the sun:) Therefore it would decrese as you got further from the sun, but the masses and therefore gravities of other planets also needs to be considered:( So to find the forse you would have to work out the effect of gravity, and its direction, and then use this to find the force pulling the moon &c away from where you want it to go, and then multiply this by its mass:)Hidden secret 7 19:45, 9 February 2007 (UTC)

It's more relevant to talk about the energy that would be required to move a planetary satelite from its orbit. You cannot merely consider all the forces currently acting on a body (which are considerable in this case), but you also have to consider its momentum, which is enormous for something with planetary mass and velocity. Invoking purely classical methods would require enormous amounts of energy to significantly alter the course of something the size of, say, Earth's moon. There are a lot of specific questions that you pose, all of which would take a good bit of time to work through numerically. I'm not even entirely sure if you could do such a thing without invoking some general relativity (though you can almost certainly approximate it "well enough" with Newton's law of gravitation). -- mattb @ 2007-02-10T02:46Z

well thanks you two, i super appreciate it, good job, yet i did remember my force and gravity equations, my question was how much force (and is it possible) to move lets say "Pluto" (lets make it easier and more specific, and avoid planetary gravity influence on their moons, and the various methods that might utilize planetary gravity fields it may pass to advantage if timed correctly,... so we're just mainly dealing with the sun and minor/neglible gravity effect of other planets)...from what i understand people think we can knock an incoming asteroid off course with just a nuke or my final question then is:...could we use the entire russian or american stockpile from 50 years of atomic reactors to "nudge" Pluto sending it out from the solar system???...(i figured this was more than a simple force equation, and i wasnt sure how nukes would play out in the equations and how they would be used to achieve their "effective force" relative to the total force held in the warhead) Benjiwolf 14:16, 10 February 2007 (UTC)

Any amount of force will move the planet, it's merely a question of how much you wish to move it and how fast. Again, you're missing the subtle point that it's not as useful to talk about force as it is energy. You also need to specify something about direction. It would, for example, take far more energy to move pluto in a direction opposite to its momentum (its current direction) than it would to move it on a path towards the center of the sun (that is, in the same direction that the centripetal force of gravity acts). Your last question is very difficult to answer without some research, but my gut tells me that there isn't enough energy in all the nuclear bombs (nevermind practicality) to alter Pluto's orbit so significantly that it would "fly out" of the solar system within a short time frame. The energy released by a nuclear warhead is extremely puny on celestial scales. -- mattb @ 2007-02-10T19:01Z

OK..thanks question wasnt exactly answered so i still have little idea as to this...yet perhaps in a million years we will be able to produce many degrees of magnitude greater the energy present in current nuke stockpiles and such a thing would indeed be achievable...moving a distant planet onto trajectory out of the solar system...its way better than a spaceship...and u can start adding all sorts of stuff to it to make it a real nice spaceship.......yet there are other ways to travel in style i think perhaps besides this...Benjiwolf 19:50, 13 February 2007 (UTC)

Keeping raccoons alive[edit]

For my project at uni, we have to argue why we should keep raccoons alive as we are to debate with a group that says that they should be made extinct etc. Any help people?

You could start with the general arguments on why extinction of any species is bad. Then you explain what happened when the wolf was hunted to extinction in many parts of the world, and why it is being reintroduced. --Zeizmic 20:56, 9 February 2007 (UTC)
I'm not sure if this would be what the moderator of the debate or whatever wanted, but costs versus benefits always works well; if you can show that it would be a lot cheaper to, for instance, buy everyone garbage cans secure against Racoon attack, than to exterminate them, then that is surely a point in your favour. --Neo 21:04, 9 February 2007 (UTC)
More importantly: If you decide to keep them alive, but change your mind next year, you could deal with them then. But if you exterminate them now, and ever change your mind in the future, there would be no way to ever get a single living raccoon back. Extinction is forever. --mglg(talk) 21:34, 9 February 2007 (UTC)
1)They are clever little animals with 2)impressive manual dexterity, 3) their skins make fine coonskin caps, 4)they are very delicious barbecued, 5)they could doubtless evolve to replace humans as he dominant species, and 6) they enable the sport of coon hunting. Those six reasons are sufficient to reject the proposition of making them extinct.Edison 04:30, 10 February 2007 (UTC)

Not sure if I'm being helpful here but I'll try. Here are just a few of the arguments that you can anticipate the oposition will bring into play: 1)They are vectors of disease, raccoon rabies anyone? 2)They decimate populations of reptiles and birds by eating thier eggs. Here you could argue that thier numbers have only skyrocketed where we have eradicated the larger predators that would have "normally" kept thier numbers in check. 3)Extinction is a natural process. 99.9% of all the species that ever existed are now extinct. 4)They are members of a relatively small family of mammals so would hardly be missed. 5)The argument that a more genetically diverse population is necessarily a stronger population is a modern myth. So the loss of 1 more species would be insignificant. I could easily pick apart any of the above arguments,as I'm sure you will. Good luck with the project. Canis sylvaticus Oops, I missed 1 that I shouldn't have. 6)Extinction need no longer be forever. given recent advances and anticipating those to come, we could put the genomes of Procyon lotor in a gene pool reserve should we ever find a reason to reinstall the species. Mea culpa. Canis sylvaticus

Articles on why conservation is a Good Thing (morally and human-centric reasons) are scattered around conservation biology, biodiversity, endangered species, and perhaps extinction. All these arguments should really all be put together somewhere. —Pengo 09:04, 14 February 2007 (UTC)

Some Biology Questions[edit]

  1. Of the three types of RNA, which is the primary transcript of eukaryotic genes?
  2. An image of a mitochondria is presented, and the question is what does it have in common with chloroplasts, the choices being DNA is present, ATP is produced, and Ribosome presence, or A and B, or all three?
  3. A nucleotide may contain: Ribosomes, Nucleic Acid molecules, AMP, ADP, ATP?
Any ideas as to the above, I disagree with the answer key on the above. ST47Talk 20:28, 9 February 2007 (UTC)
How about telling us what you think the answer is and why so someone can see how/if your logic is wrong. Just being told the answer is no way to get an education... DMacks 21:34, 9 February 2007 (UTC)
OK. #1 my response was mRNA, assuming that since they are limited-use, they would need transcription more often than re-usable ribosomal subunits and tRNA. The given answer was rRNA. #2, I knew both produced ATP, and I know both have their own DNA, I do not think either have ribosomes, so my answer was D: A and B. The Key said A, B, and C. #3, I put Nucleic Acid molecules, which is just plain wrong, but nucleotides don't contain any of those - AMP IS the Adenine nucleotide of RNA, so I suppose that was the reasoning, as that was the given answer on the key. ST47Talk 21:56, 9 February 2007 (UTC)
1: see our articles on mRNA, tRNA, and rRNA. Yeah, seems like mRNA would be a reasonable answer assuming we're talking about nuclear genes. 2: visit the "structure" section of our pages about mitochondria and chloroplasts. That third question is pretty confusingly worded indeed. DMacks 23:04, 9 February 2007 (UTC)
For part 3, If you look at the topic of nucleotide, can can see that AMP ADP and ATP are nucleotides, and that a nucleotide contains a heterocyclic base a sugar and one or more phosphates. You could say that ATP contains AMP or ADP, or that ADP copntains AMP, so there are two possibles from that list. GB 07:37, 10 February 2007 (UTC)

I believe the answer key is correct for all three questions.

1. The way i interpreted the question was which is transcribed the most, not which is transcribed the most often. Of all the RNA transcribed by a cell - i'd imagine rRNA would be the most (therefore the primary transcript). Simply because there is so much ribosomes in a cell and they all rely on rRNA to function, so therefore a hell lot of rRNA. Although mRNA may be transcribed more often (this also depends on what type of cell we're talking about), mRNA is also commonly broken down pretty quickly. Often, for a single mRNA, there are TONS and TONS of ribosomes (all with rRNA) translating it (see Polysomes). So it's like...for everything the cell transcribes, rRNA would be the most, hence the primary transcript.
2. Both mitochondria and chloroplasts defintely have their own ribosomes (prokaryotic ribosomes in fact, which supports the endosymbiosis theory). Those two organells divide on their own, and can produce their own proteins (although the host cell also supplies a lot). They both have DNA, they both have ribosomes, and they both (can) produce ATP
3. A nucleotide contains AMP. AMP is adenosine mono-phosphate - which consists of a adenine, a pentose sugar, and a phosphate group. In other words, the nucleotide with adenine is in fact a "adenosine mono-phosphate". But generally, when we're talking about nucleotides, we call it a "adenine nucleotide", and not "adenosine mono-phosphate". However, this is only for RNA. DNA has deoxyribose sugar and not ribose sugar.

Does that explain everything? --`/aksha 08:58, 10 February 2007 (UTC)

Yes, thank you! ST47Talk 13:09, 10 February 2007 (UTC)

Flame test[edit]

In the flame test why do you see different colours from different salts? How is this colour made? Thanks for your help! --Flying Canuck 21:49, 9 February 2007 (UTC)

Well, um, as our flame test article explains, this is due to "an element's characteristic emission spectrum." And as our emission spectrum explains, the colors are based on "the frequency of the light [electromagnetic radiation] the element emits when it is heated". Were you looking for more than that? --Steve Summit (talk) 22:38, 9 February 2007 (UTC)
Sort of, but what causes the emisson spectrum to be different for each element?--Flying Canuck 18:53, 10 February 2007 (UTC)
The one-liner answer is "quantum mechanics". The energies of the photons (and thereby, their wavelength) emitted from an excited material are equal to the amount of energy lost by the electron transition that caused their creation. See spontaneous emission, atomic spectral line, and spectral line. Note that this process is also somewhat reversable, and one can characterize materials by the wavelengths of light they absorb (the basis of many forms of spectroscopy).
With respect to the flame test, I'd imagine that the characteristic color is produced from the many radiative transitions that occur when electrons excited by heat and the chemical reaction of oxidation change energy state in the correct manner. -- mattb @ 2007-02-10T19:27Z
To try and make this a little more lucid, let me explicitly point out that the particle energy profiles in different atoms and different combinations of atoms varies a good deal. -- mattb @ 2007-02-10T19:29Z

Why is that....?[edit]

1) When you take out earrings it feels like there's a little ball inside your earlobe? 2) What is the function of yawning and stretching - and why is it catchy? 3) What actually happens when you have 'pins and needles' or your leg is 'asleep'?

Thanking you,

San 23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)~

Regarding 2), have you looked at Yawn? Regarding 3), check out Paresthesia and Obdormition. --Lph 00:47, 10 February 2007 (UTC)
[edit conflict]
1. No clue.
2. See yawn (especially the section on contagiousness), and stretching (especially the two nice cat pictures).
3. I believe it's due to prolonged pressure on a nerve bundle, perhaps when it's pinched against a bone if you're sitting or lying awkwardly.
Steve Summit (talk) 00:54, 10 February 2007 (UTC) 00:54, 10 February 2007 (UTC) 00:54, 10 February 2007 (UTC) 00:54, 10 February 2007 (UTC)
1) This is only a guess. It might be because you have become accustomed to having something in there, and when it is gone, it feels strange. In your case, like a small ball. − Twas Now ( talkcontribse-mail ) 02:43, 10 February 2007 (UTC)
If your ear is pierced, the scar tissue in the lobe feels like a ball. If they are not pierced, there is nothing there. Many guys who grew up in the 80's can do a comparison as they will have only the left ear pierced. --Kainaw (talk) 05:26, 10 February 2007 (UTC)
It may not be just scar tissue. Collagen fibers form when soft tissue experiences shear, whether or not there's any scarring; the ball you feel may be like an internal callus.--Joel 08:05, 10 February 2007 (UTC)

Stop Global Warming ![edit]

Why hasn't more attention been given to simply shielding the earth from sunlight? A series of thin, mirrored panels between the earth and sun would be more effective than trying to clear greenhouse gases from the atmosphere.

The costs for that would be huge, and it wouldn't really work since Earth rotates around itself and the Sun. Also, we'd lose so much of the visible sky that anyone involved in astronomy (that is, anyone who'd be involved in such a project) would reject the idea as preposterous. — Kieff | Talk 00:33, 10 February 2007 (UTC)
You could always put the panels at the L1 Lagrange point; that would keep them fixed on the line between the Sun and the Earth. That said, it would be cheaper to just throw the panels into a low Earth orbit, and accept that for a bit more than half of each orbit they would be in the Earth's shadow and not providing any shade.
The decrease in sunlight would need to be fairly low; astronomers would only lose 1% of their sky, give or take. If you put the panels in a polar orbit, then only a very small part of the sky would be permanently hidden from sight.
Paul Crutzen (who won the 1995 Nobel prize in chemistry for his work on the ozone hole) has suggested the use of balloons or artillery shells to spread dust in the upper atmosphere; this would be an alternative way to increase the Earth's albedo and reflect more sunlight. He estimated the the cost at about $25 billion per year to maintain the dust level: [3]. TenOfAllTrades(talk) 02:32, 10 February 2007 (UTC)
The decreased sunlight can also lead to an increase in depression around the world.[4] - Akamad 00:54, 10 February 2007 (UTC)
(delayed due to an edit conflict) A cheaper way would be to spin basalt fibers from, e.g., moon rock, and weave fine gauze to diffract the light, rather than reflecting it. Large panels of this might be placed at L1 between the earth and the sun without too much loss of astronomical data, or ongoing thrust. With an oversized weave, they'd be more effective at diffracting IR radiation than visible light, minimizing the psychological effect. But it would still be insanely expensive, and control over the facility would be a nearly insoluble political problem, since it would enable a person to hold the world hostage.--Joel 02:37, 10 February 2007 (UTC)
Dyson sphere contains a bit of discussion about just how huge an undertaking engineering something like this would be. -- mattb @ 2007-02-10T02:56Z
Too bad it isn't that easy to alter the global systems in a purposeful, systematic way. *rolleyes* It is really a stupid idea to try and do this in any way at current times. [Mαc Δαvιs] X (How's my driving?) ❖ 03:10, 10 February 2007 (UTC)
Becuase the the consequences of doing so could be infinitely worse. There are LOTS of questions about global warming including the natural vs. man-made element. The earth and sun both go through cyles that span millenia. Dinking with it using weather science that can't predict next weeks forecast would be extremely irresponsible. For example, the main component of greenhouse gases in the atmosphere is water vapor. When the earth heats up, more water is evaporated from the oceans into the atmosphere. This is a postive feedback cycle. More heat, more water evaporation. more heat trapped by greenhous gasses, more water evaporation, etc. BUT, water vapor forms clouds. These clouds refelect heat into space, cooling the atmosphere, which can't hold the water, reducing the greenhouse gases throgh rain. So which process wins or when does global warming get stopped by clouds? These are fundamental questions about the behavior of the atmosphere that needs to be answered before any radical steps are taking. Man using science to help nature doesn't have a very good track record. --Tbeatty 05:20, 10 February 2007 (UTC)
Be fair. There's a world of difference between local weather and global climate. Actuaries can't tell you the date of your death, but they're good at saying what proportion of a given population will survive. Similarly, I don't expect that any of the climate models try to predict the cloud cover over a particular square mile on a particular day, but I imagine they're pretty good about global averages on a scale of decades.--Joel 08:01, 10 February 2007 (UTC)
I am being fair since most of the "fix global warming now" ideas try to affect the locally temporal weather in an attempt to change the climate. Wouldn't it be a kick in the pants if the man-made solution to global warming actually made the summers hotter but the winters much colder? I dont't think anyone would think more hurricanes and more blizzards would be a good idea even if the it reduced the temperature by .3C on average over 100 years. Summers up 9 degrees, winters down 10. Great, global warming ended. It is essential that the local variation be predictable and not just the long term climate. Even short range actuarial prediction is awful. How many major hurricanse were predicted for the atlantic in 2006 using very sophisticated models? We didn't them to predict when or where, just how many over a 6 month period.
Climate models have been predicting warming since 1980 when the Global Cooling models failed. None of them have been accurate, though in terms of predicting temperature rise over 20 years. Also the models are currenlty conflicting about cloud cover as a climate forecast (not the idividual square mile forecast). They do not know how much global warming induced cloud cover will affect global warming. Tbeatty 15:48, 10 February 2007 (UTC)
I'll give another example. I would like to see the global models predict the warming and cooling of the pre-industrial climate. It needs to be able to predict the multiple cycles (i.e. hundreds of year, decadal and millenial cycles of warming and cooling). It's very difficult because it depends on natural events (i.e. comets, volcanoes, sun cycles) that we currently cannot predict yet they are ongoing natural events. It may be that actuarily, comets hit the planet whenever the earth has warmed to this level, or volcanoes erupt, etc. It would defnintely suck to put up a permanent, irretrievable collection of mirrors the day before a major volcano eruption. Or a year, or 10 years before we saw the giant comet on a collision course.
Man has always thought he is more important and more influential in the universe than he actually is. That truth did not change with global warming. --Tbeatty 15:48, 10 February 2007 (UTC)
See: Global dimming. There was a Nova program about it. -- 20:28, 10 February 2007 (UTC)
In any case, such a sunshield would do nothing to fix ocean acidification, an equally serious problem caused by greenhouse gas emissions that has received comparatively little attention. --Robert Merkel 03:35, 12 February 2007 (UTC)