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November 26
Crystal structure affecting properties of Group 2 metals (retrieved from archive)
I'd be very grateful for any helpful pointers you have here, even if it is a just a link to a site with the answer.
I've found out that Be and Mg are Hexagonal Close Packed crystal structures; Ba is Body Centred Cubic and Sr and Ca are Face Centred Cubic. However, I can't find anywhere telling me how this crystal arrangement can affect the physical properties of a pure metallic sample of the substance. Any guidance would be greatly appreciated! Thanks, --86.139.127.2917:28, 24 November 2006 (UTC)[reply]
One immediate impact is the co-ordination number. HCP and FCC are close-packed structures with a co-ordination number of 12, but in BCC it is only 8.--G N Frykman19:15, 24 November 2006 (UTC)[reply]
The physical properties (strength, melting point etc) of a HCP or FCC structure would be very similar all other things being equal.. So in your case atomic radius amongst other factors would be a big factor in the physical properties. As for Ba I can't see any logical reason why it would be BCC when 12 coordiantion is clearly easily attainable - are you sure it is body centered cubic?87.102.33.10019:31, 24 November 2006 (UTC)[reply]
So crystal structure has little effect on physical properties? I was told that the fact that Calcium has a higher melting temperature than Be is because of the crystal structure of Ca. Why is this? As for the structure of Ba being body centred cubic, I got that information from the barium page... Is it incorrect? --86.139.127.2921:26, 25 November 2006 (UTC)[reply]
(Be/Ba typo? above?)
Going down the group 2 metals (data from wikipedia)
m.p.: Be 1560 Mg 923 Ca 1115 Sr 1050 Ba 1000 (Ra 973?) (in kelvin)
Ignoring Mg for now, the melting point decreases going down the column.
(at least) Two factors contribute here; the mass of the atom - heavier things melt and boil higher (as in the flourine, chlorine, bromine, iodine series).
The other factor is the strength of interaction between the atoms - which will probably decrease going down the column. It seems that the interatomic interactions have the upper hand here.
I can't explain the 'blip' at magnesium..
Note that otherwise the harder elements melt higher (hardness is also a measure of interatomic interaction strength).
As for the crystal structure of Barium I haven't verified its structure but as I mentioned above - is there any reason why it would not be 12 coordinate close packed.. 83.100.138.722:51, 25 November 2006 (UTC)[reply]
To understand the need for Oxygen, you need to understand how the human body functions. Proteins are extremely important building blocks of your body. Proteins hold your genetic information (DNA), insure communication between neurons (neurotransmitters; e.g. your brain wouldn't be able to transmit a signal to your lungs without proteins), protect your body (antibodies), and do a thousand other useful tasks. Of course, proteins don't grow on trees; your body has to build them (ironically, from and using other proteins). The process is known as anabolism. Anabolism cannot take place unless energy is provided. The combustion of oxygen (oxidation or catabolism) inside your body's cells provides all the necessary energy. Additinally, your body needs the energy produced by oxidation to keep its temperature constant and of course to enable you to move your muscles around. There's a little more detail to it, but that's basically why we can't survive without Oxygen. LestatdeLioncourttalk12:53, 26 November 2006 (UTC)[reply]
The previous post contains some ambiguous/erroneous statements. To clarify:
Proteins do not hold your genetic information. DNA is not made of proteins, although proteins are important for packing DNA (histones), and synthesising DNA.
Neurotransmitters are not in genereal proteins. As stated in the article, some amino acids serve as neurotransmitters, and some short peptides also do, but many neurotransmitters are other, small molecules. However, the receptors for neurotransmitters are proteins.
Breathing results from the brain/medulla sending signals to your diaphragm and intercostal muscles, not to the lungs. However, bronchoconstriction is regulated in part by nervous signals.
I'm well aware of the overgeneralizations I made when it comes to the brain-lung connection and neurotransmitters. I just meant to illustrate a point in the simplest way possible. With regards to DNA, then I must admit it was a mistake. My apologies. LestatdeLioncourttalk14:08, 26 November 2006 (UTC)[reply]
D. Gary Young, Young Living Essentials and Raindrop Therapy
Can someone write an article? quackwatch.org has a good one I think.
I've read and heard that studying a person's hand can yield more useful results than "Your life line is very shor - LOOK OUT!!! Kidding." (Good times.) However, I'm having trouble finding information on it. All I can find is people saying Greek gods influence your live vs. people getting off on saying that's stupid.
I'm interested in things like:
What callouses most often form as a result of what kind of labor?
Playing guitar or harp, I believe, tends to create characteristic callouses on the fingers and thumb, whereas wielding a shovel (as I know by experience) causes equally characteristic callouses on the side of the thumb, at the bases of the fingers, and across the heel of the hand.
Don't forget bowling! My dad and I both have calluses at least on the side of my thumb, looking at my own. It's smaller and pretty soft and red now. Been a while, and it wasn't developed very well anyway. X[Mac Davis] (DESK|How's my driving?) 08:37, 26 November 2006 (UTC)[reply]
Do things like typing, painting, writing (by hand), playing an intstrument, etc. have visible effects on the skin, muscles, bones, ligaments, or soft fascia of the hand? Seems like they should.
Extreme examples, of course, would be carpal tunnel syndrome or accidentially cutting off a finger chopping meat.
It seems that different manual activities would cause the muscles of the hand and forearm to grow to different sizes. Is the result visible and interpretable from the outside?
Could I, for instance, determine whether a person uses their superficial digital extensor muscle more than usual without cutting their arm open?
The hand, wrist, and forearm, like other areas of the body, build up layers of fat as the person they're attached to does, and they're generally in a certain proportion to the rest of the body. Pretend they're sticking their hand through a curtain. What could I tell about their build and general physical health?
Obviously, if their hand is several times as thick as their wrist, they're unhealthy, and if their hands are tiny, they might be as well.
Different people care for their hand in different ways, and to different degrees. What characteristics of the hand that are under voluntary control are reliable indicators of characteristics of the person themselves?
To get the ball rolling, an easy example is nail polish - red nail polish is a pretty reliable indicator that the owner of the fingers is female (or pretending to be), though black, neon, or pictoral polish is of course less certain.
Men's hands biologically and environmentally tend to have rougher skin. Look at a hundred hands, and you can probably get good at picking out a man's hand or a women's hand unless they're all trying to fool you. X[Mac Davis] (DESK|How's my driving?) 08:37, 26 November 2006 (UTC)[reply]
I would like to hear both anecdotal and scientific claims, and I'd especially appreciate a link to someone who studies this for a living. Black Carrot06:44, 26 November 2006 (UTC)[reply]
I'll give you something anecdotal, I'm left-handed and as a result if I write a lot with a pencil or a pen, I get a callous on the inside of my middle finger on my left-hand; a right-hander would get something similar or their right-hand. So you could at least tell what somebody's dominate hand is. --Cody.Pope07:02, 26 November 2006 (UTC)[reply]
Callouses form due to different types of uses of the hands, but these are very temporary and only reflect recent work. I do not believe that bone structure, or the shape of hands can be used to determine anything about the labour a person has done in their lifetime (other than perhaps missing digits); there is just too much genetic variety that would cover any effects (if any) that continual use would have on their development. Furthermore even someone with "strong hands" would have more muscle mass in their forearms rather than visible in their hands themselves. - Rainwarrior08:34, 26 November 2006 (UTC)[reply]
I know that there are a lot of ways to approach this question but I'm looking for an answer from a purely biological/medical perspective.
Are there any negative effects on males if they don't ejaculate regularly? What possible medical problems could happen to a man if he went a long time (say, months or years) without ejaculating? For the purposes of this question, the method of ejaculation (intercourse, masturbation, nocturnal emmission, etc.) is irrelevant. There are a few things that I have heard might happen but only from unreliable sources.
The body normally absorbs unused sperm from the testicles but it can only do so much of that. Too much absorbtion can cause sterility. I have anecdotal evidence for that. A friend of mine who recently has his vasectomy reversed was told by his doctor that he was probably still infertile because his immune system had begun attacking his sperm.
The seminal fluid in the prostate would either get reabsorbed by the body or harmlessly backed up into the bladder but again too much of that can cause damage. The article on prostate cancer says that frequent ejaculation can reduce the risk of getting prostate cancer.
The smooth muscles that cause ejaculation are just like any other muscle in the body and will entropy if they go too long without use.
I haven't read any scientific data about the possible problems that occur and it's not something that would have many cases, but I was wondering if anyone else was familiar with any research about this. --69.137.93.24707:46, 26 November 2006 (UTC)[reply]
I've read it will have no effect (in one of those for-teenagers, get-to-know-your-body type books), and I'd buy that. It's not like people don't go for years without sex. And in the past, masturbation was rather less acceptable than it is now, so I'd bet there have been many people who went years, decades, or even their entire lives without it, especially religious leaders. Vows of chastity and all that. If there were a significant negative effect from it, it seems like I would have heard of it. However, I have read that frequently holding it in (for birth control, or something) can damage things mechanically. Black Carrot07:53, 26 November 2006 (UTC)[reply]
I've heard that men who ejaculate regularly are less likely to have prostate problems in older age. By that I mean that men who continue to ejaculate after middle age are less likely. I don't know exactly how often ejaculation was necessary in order to make a difference, but I believe it was whatever would qualify a man as 'sexually active', like maybe once or twice a week or more. I don't have any references for that offhand tho. Anchoress08:06, 26 November 2006 (UTC)[reply]
When I was doing Physiology at Uni I asked the Professor who was (and is) one of the world experts in reproductive biology a similar question, basically the original question 1 above. He said the sperm were reabsorbed, and did not suggest that it would cause any long-term problems or that there were any limits to it (though bear in mind this was almost 20yrs ago so there could have been new findings since then).
I have heard from other sources about possible increases in risk of prostate cancer and other prostate problems, as noted in the Qu2, the article, and as Anchoress says.
Re Qu3 I think you mean atrophy, not entropy; for some reason I seem to remember that smooth muscle is far less prone to atrophy than is skeletal/striated muscle, but I don't have any references for that.
Also don't forget the possible role of nocturnal emissions as, I suppose you could say, a replacement or safety valve for intentional ejaculations, although I don't believe there's really any clearly demonstrated link or definitely known cause for nocturnal emissions. --jjron13:07, 26 November 2006 (UTC)[reply]
Seriously could you actually go for say 1 week without having sex or masturbating? (males?) As if sperm would ever get chance to be reabsorbed - after a couple of days in my experience the hands go into autopilot no matter what, where or why.87.102.12.12913:50, 26 November 2006 (UTC)[reply]
Ive gone atleast 10 days. Its not that hard, especially if your feeling low, and not particularly aroused. Im sure I could go much longer if I had a motive. PhilcTECI00:03, 27 November 2006 (UTC)[reply]
My grandma is staying over out our house for a few days, and I noticed a minute ago that the bathroom smells like old people. A while ago on the desk (many months, as I recall) somebody asked a question about "black people smell," and one of the answers was that some some black people have different sweat, or something like that. I have noticed this, some black people (particuarly ones that haven't washed for a while)... smell different from other people. Is it old people's sweat glands being old? Just kidding. I noticed that there was denture fluid in the room sitting out with her dentures in it— maybe that's it! What do you think? X[Mac Davis] (DESK|How's my driving?) 08:27, 26 November 2006 (UTC)[reply]
It could be something as simple as old people preferring certain types of perfume. Not just pure perfume, but also in soap and such, which is almost always perfumed (to my great disgust). DirkvdM10:39, 26 November 2006 (UTC)[reply]
I assumed (without giving it much thought) that my grandmother's smell was related to her age until I found out it was the smell of her cosmetic powder. --LambiamTalk15:40, 26 November 2006 (UTC)[reply]
As someone who is neither young nor old could I point out that university students also smell - it's a strange smell - like raw soap - any clues?87.102.12.12915:45, 26 November 2006 (UTC)[reply]
And then there is that nursing home smell where when you go to visit grandma your nostrils get hit with the smell of stale urine. The worst smell is the smell of patients with cancer and certain other illnesses. 71.100.6.15217:03, 26 November 2006 (UTC)[reply]
Because the sense of smell tails off in older people, they tend not to notice smells as much. So they dont think anything particulartly smelly. So they dont feel the need to wash it/ freshen it up!--Light current13:51, 27 November 2006 (UTC)[reply]
The scent you emit also depends a lot on diet. You can notice this easily if you shower up a while after eating a lot of garlic -- it ain't just your breath that contains the odor. But it's just as true on a more micro level based on your day-to-day diet.
Hmmmm, "some black people (particuarly ones that haven't washed for a while)... smell different from other people." So, not all black people who haven't washed for a while smell different from other people? Do white or brown people who haven't washed for a while "smell the same as other people?" As each other? I'm going to have to go around sniffing people of different colors to see if this is true. Did you ask them how long it has been since they washed or if you smell different to them when you haven't washed for a while? And how long is a while? Days? Weeks? Years? Do I need a survey card for differently aged aromas or is ballpark good enough? I always wondered what people smelled like in the Middle Ages but never wanted to time travel to find out personally.
I need some formula for work, please can you guys help
One (or many) relating energy (eV) recquired to free electrons and number density of free electrons (e/m³) at a given temperature (K)
One (or many) relating number density of free electrons (e/m³), velocity of electrons (m/s) and current (A)
One (or many) relating number density of free electrons (e/m³), velocity of electrons (m/s) and voltage (V)
the variables given are not limiting, if further variables or constants can be brought in if neccesary, but if you do have to bring in further variables, It would be helpful if you helped me find them aswell, as I would like to able able to calculate conductance for a substance, given its ionisation energys. Thanks. PhilcTECI12:57, 26 November 2006 (UTC)[reply]
(response to Q2) I can give you this one : Density of free electrons (e/m³) x Cross sectional area A (m2) x velocity of electrons (m/s) gives current in electrons per second. to get Amperes multilpy by the charge on an electron in coloumbs (–1.6 × 10–19 Coloumbs per electron)87.102.12.12913:54, 26 November 2006 (UTC)[reply]
Response to Q3: The previous post practically gets you half way to this answer. The relation my friend up there reached is:
I = d × A × v × -e
where:
I is the current in A.
d is the density of free electrons in m.s-3.
A is the cross-sectional area in m2.
v is the velocity of the electrons in m.s-1.
e is 1.6×10-19 C.
Using Ohm's Law which states that U = RI, where U is voltage (in V), R is resistance (in Ω), and I is current (in A), you can easily modify the above relation so that it becomes:
You can deduce this relationship via dimensional anaylsis. R×e gives: [Ω] × [C] = [(Kg.m2)/(C2.s)] × [C] = [(Kg.m2)/(C.s)] = [Wb] which the unit for magnetic flux. You can leave the relation as it was. I just thought that reducing the number of invovled variables might suit you better. LestatdeLioncourttalk15:29, 26 November 2006 (UTC)[reply]
Interesting, but how does this help - is there a way of calculating magnetic flux so that it can be used to give an answer to one of the original three questions?87.102.12.12915:36, 26 November 2006 (UTC)[reply]
I really gave no thought to the matter beyond somewhat-pure math, i.e. regardless of context. The question asks for a relation(s) between the given physical quanitites, and I'm providing two.
"if you do have to bring in further variables, It would be helpful if you helped me find them aswell" - ie we need a way to calculate or otherwise get the magnetic flux.87.102.12.12915:58, 26 November 2006 (UTC)[reply]
Ah yes, you're right. Calculating the magnetic flux is a little complicated and depends on the conditions of the problem. One way is to integrate the negative value of the electromotive force in a circuit or to use the magnetic flux density, B (expressed in Tesla, T). In the latter method, the formula is dependent on the medium (e.g. for a loop it is equal to the scalar product of B by n, the normal vector to the loop obtained by the right-hand rule, multiplied by the surface area in square meters). It's probably much easier sticking to the first relation. LestatdeLioncourttalk16:54, 26 November 2006 (UTC)[reply]
Dependency of climate on the Earth's axis of rotation
My daughter just asked me what the climate would be like on Earth if the Earth's axis of rotation were parallel to the ecliptic plane, instead of at the angle of approx 67 degrees that it has. My immediate answer was that the climatic variations would be extreme, since the 23 degrees off perpendicular is what causes the seasons. This would certainly be true for the poles, where the sun would be more or less in zenith all day in midsummer. But what about the equator, and the regions in between? Would any part of the planet have a comfortable climate? --Norwegian Bluetalk17:03, 26 November 2006 (UTC)[reply]
I'm not sure if science would have an adequate answer...the best is probably to say that we simply wouldn't know. However, it does sound like an Earth that wouldn't be a very fun place to live. The moderate temperatures probably couldn't be sustained in those regions in the long term due to the sensitive equilibria set up. --HappyCamper18:06, 26 November 2006 (UTC)[reply]
Good question - the current equators would experience 24hr daylight and in 6months 24hr night (a bit like the poles today except this would be total daylight - total night). the poles would get the sun on the horizon as they do today when they are at the poles - but as the rotation moves the pole 90degrees round depending on the time of year they would get either 1 the sun stays fixed in the sky at the horizon, 2 (1/4year later) the sun goes from horizon to opposite horizon via directly over head (like summer 12hr day) and then back to 3 the sun stays fixed in the sky at the horizon (opposite side etc). So the poles would have a summer and a winter. But a point on the equator along the axis of rotation would have 1 day = 1/2year light then 1/2year day. This suggests to me that the ice caps would move completely around the earth in one year - move to the poles.... Happy Xmas83.100.250.5320:28, 26 November 2006 (UTC)[reply]
I can't follow this. The current equator (there is only one) would still be an equator, having each day 12 hours of light and 12 hours of darkness (not counting twilight), assuming that the Earth rotates around its axis once every 24 hours (not counting the fact that now we need to consider the sidereal day). At midsummer and midwinter, the equator would have constant twilight. I agree with the hypothesis that the caps would move from pole to pole, but not in a continuous way. The cap would be much larger at its largest extent. --LambiamTalk00:01, 27 November 2006 (UTC)[reply]
In NorwegianBlue's hypothetical situation, Earth's axis of rotation is pointing toward the sun during summer. In other words, the tilt is 90 degrees instead of 23 degrees. The equator would be in 24-hour sunlight during both summer and winter, but it will have 12 hours of light and 12 hours of darkness during spring/autumn (when Earth's axis is pointing 90 degrees away from the Sun). Therefore, it will be hotter than it is right now.
As 83.100.250.53 said, one day at the poles would be 6 months long. However, the poles will be hotter than they are right now, because it's possible for the Sun to be directly overhead (whereas now the Sun can't rise higher than 67 degrees, i.e. 90-23). All other latitudes will spend some days/months in darkness, but for at least half a year they will never spend more than 24 continuous hours in darkness.
So, to conclude, Earth's average temperature would be higher. I don't think it would be higher than 40 degrees Celsius, though, so life would still have a chance to evolve. --Bowlhover04:22, 27 November 2006 (UTC)[reply]
You assume the axis is constantly pointing towards the Sun, which would probably eventually happen if the situation were to last. But it could also stay in the same orientation relative to the solar system, which would cause extreme seasonal changes at the poles, too extreme for 'more developed' life, I assume. The equator would be a bit like the present poles at spring/fall twice a year and be as they are now (normal day/night pattern) during those other two seasons, as Lambian describes. This would be quite live-able because there would be no extreme long dark periods. Btw, Uranus has that. From the article: "Uranus is nevertheless hotter at its equator than at its poles, although the underlying mechanism which causes this is unknown." That's it. Not much help there. The Earth, however, has experienced a more tilted axis several times in its history. I can't find the article and I don't really have the time right now, but axial tilt might help. DirkvdM07:49, 27 November 2006 (UTC)[reply]
In my answer I assumed that the axis initially points towards the sun but holds its position as the earth rotates around (so that after 1/4 year the axis of rotation is actually at right angles to the line connecting sun and earth). Hope that makes it clearer for anyone who was confused. And the polar regions change from one pole to two poles to one pole etc over 1/4 yearly intervals - I initially didn't get that..87.102.20.21917:38, 27 November 2006 (UTC)[reply]
Thanks for your responses! Bowlhover, I think the maximum solar height at the poles is 23°, not 90°-23°, and Dirk, to me it is inconceivable that the axis would eventually point towards the sun all year. Rotating the planet's axis once a year would require an enormous amount of energy. I'll think a bit more about the celestial geometry on my hypothetical planet, and maybe post a follow-up on the maths desk. --NorwegianBluetalk23:36, 27 November 2006 (UTC)[reply]
If the mass of the planet is unevenly distibuted between the poles, the heavier one will get drawn towards the Sun more and more. I'm not sure if a molten core will counteract or re-enforce this. Anyway, given that the Sun's attraction is the 'point of reference' here, it would actually cost energy to move in relation to that, and a pole moving away from the Sun would do just that. DirkvdM05:57, 28 November 2006 (UTC)[reply]
I think this is what happened to the Moon, which is why the far side has much less mares than the near side. (See the pictures on the Moon article. The difference is amazing.) By the way, I think that having a (symmetrical) molten core will neither re-enforce nor counteract this process, as long as Earth's mass stays the same.
To NorwegianBlue: you're right, the Sun can only get to 23 degrees at the poles. I don't know why I said 90-23; it should have been 90-(90-23). --Bowlhover01:34, 29 November 2006 (UTC)[reply]
Because your body is diverting resources (blood energy etc.) to fighting infection, and therefore has less available for digestion. So it will try to keep your food intake low making you not hungry, or throw up if you eat to much. It will still take a minimal amount of food, i.e. enough to survive happilly. PhilcTECI18:30, 26 November 2006 (UTC)[reply]
If your digestive system is infected, there's little point in eating, as you will likely vomit or have diarrhea to rid the digestive tract of the infection, so won't get much benefit from the food. StuRat09:56, 29 November 2006 (UTC)[reply]
Who studies the origin of neurosis?
Are neurotic states studied only by psychiatrists or do neurologists try to discover their cause? My son had a severe anxiety disorder, the cause of which is unclear. We have seen numerous psychiatrists and therapists who mostly insist that family dynamics are responsible. This just doesn't seem a good enough explanation when we are a stable, rational, loving family. We have never been referred to a neurologist. Is this because such disorders are not part of their remit? Really Is it possible that anxiety disorders result from neurological impairment?
remeber thinking your normal, does not constitute normaility, and denile may be the tip of the iceberg of an underlying problem. PhilcTECI21:05, 26 November 2006 (UTC)[reply]
Neurologists are not involved in the diagnosis or treatment of anxiety disorders, except possibly helping to exclude that "the disturbance is ... due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition (e.g., hyperthyroidism)." (This partial quote is from the descriptions of the conditions, and the main articles referred to in the page on anxiety disorders.) Usually a neurologist would get involved only when a general physician finds that he needs such an opinion. As far as dynamics are concerned, the difficulty is that what matters is not what you perceive, but rather what your son perceives - how his mind experiences things. These two may not correspond, and the reasons for that may be unknown to you at present. Seejyb22:34, 26 November 2006 (UTC)[reply]
Several anxiety disorders have a genetic component to them. Thus they would not necessarily result from abnormal "family dynamics", but rather from some physiological cause. A good psychiatrist should know this, and prescribe treatment accordingly. In any case, this is usualy something not dealt with by a neurologist. Nrets02:49, 27 November 2006 (UTC)[reply]
Thank you for taking the time to reply. The comment by Nrets was particularly useful for obvious reasons...I will not pursue a referral to a neurologist.
I knew as I was writing my question that the automatic assumption would be to see me as in denial about the importance of family dynamics in anxiety disorders. But, where does this assumption come from? We no longer question why people suffer from disorders - we think we know by trawling life experiences for explanations. Sometimes traumatic experiences do cause mental disorders, but that does not mean that they always do. Causes may not always be environmental. No one would claim that the human mind is fully understood. There are so many areas of ignorance and ambiguity. It's just not good enough to automatically assume that family dynamics causes disorders in children or adults. It is not a given, just a possibility.Jazzy Holiday19:09, 27 November 2006 (UTC)Jazzy[reply]
I would not automatically assume family dynamics problems as the cause of the anxiety either. Consider that if you son is in school age he could be a victim of bullying. Mr.K.19:54, 27 November 2006 (UTC)[reply]
Do natural levees develop during floods because slower moving waters can only carry smaller particles?
I mean "a condition of light winds and poor vertical mixing (no rising air) that can lead to a high concentration of pollutants"
I think you've listed the major causes. One other I can think of is physical barriers, like the trees in a thick forest or jungle. StuRat22:29, 29 November 2006 (UTC)[reply]
insulation?
When installing insulation in wall cavities in the pacific north west, should the vapor barrier go on the outside or the inside? Thanks!
Green side up! (oh, that's for sod!). Standard practice everywhere is for a breathable Tyvac (waterproof) outer cloth on the studs, and plastic on the inner studs, with insulation in the middle. --Zeizmic00:41, 27 November 2006 (UTC)[reply]
So, from the outside in - shingles, breathable layer, insulation, plastic layer, drywall?
Not quite everywhere. The vapor barrier must face the warmer, more-humid side so as to prevent water vapor entering the insulation, traveling to the point in the insulation where the air cools to the dew point, and having the water vapor condense out as liquid water, wetting the insulation.
Whether it's the inside or the outside of the house that's warmer and wetter depends on both the local climate and often, the time of year. It's hard to reverse the insulation seasonally, though, so for much of the temperate zone, we compromise and put the vapor barrier facing the inside (which is the right answer for much of the year and not too wrong for the rest of the year). But I think you'll find that in the more tropical zones, when they insulate at all, they may put it up "backwards" because the air conditioning keeps the inside cooler than the outside's warm, humid air.
This [2] shows the diagram. And it's tyvek house wrap. There are new framing techniques that prevent cold spots at corners, and it is quite the skill to properly wrap a house without holes. You should read books. --Zeizmic13:25, 27 November 2006 (UTC)[reply]
Thank you - I do read books, but there is conflicting advice in some of the books on insulation that I have read where remodelling of older houses is concerned!
Hymen of elephants and whales
How thick is hymen of a whale? How thick is elephants hymen? How big is the hole in the hymen?
November 27
Magnets
What is the specific effect - if any that magnets have on recorded items,ie: video tapes, CD's,audiotapes ?
The effect you are after is called Degaussing, as explained in that article, it is used on purpose to bulk erase magnetic media, but it does often happen by accident. Vespine02:30, 27 November 2006 (UTC)[reply]
Note that the fact that cd's are not intended to work through magnetism doesn't mean that magnetism can have no effect on their functionality. Not that I know an effect it could have, but the coating contains metal, I believe, and magnetism could have some effect on that that has some effect that has another effect that may damage the readout of some bits. Or something. DirkvdM08:00, 27 November 2006 (UTC)[reply]
The metals used are generally non-magnetic, though, so unless you're moving the magnet or disc fast enough to induce a substantial electric current, a magnet should have no effect on any form of CD or DVD (including -R, +R, -RW, or -RAM). (It might be kind of interesting to see if a disc-destroyer could be built by whirling a disc very rapidly in a very intense magnetic field. Would the disc burn up before centrifugal force shattered it?)
Note that certain discs use magneto-optical (Curie point) recording; these might be affected by high-intensity magnetic fields.
An ion of chlorine is a chlorine ion, a chloride ion is an ion of chloride. Chlorine is only a chloride when it is in a compound. Since most chlorides are salts and most salts are ionic compounds a chloride can be also be an ion of chlorine. But an ion of chlorine isn't necessarily an ion of chloride. This may sound like I know what I'm talking about but this is my understanding, I'm not actually a chemist. Vespine02:23, 27 November 2006 (UTC)[reply]
A chloride ion is a Cl− ion. This is the only ion of chlorine you're likely to encounter in chemistry, but a chlorine nucleus can have any number of electrons around it, from a bare nucleus (Cl17+) to Cl− or even Cl2− (depending on whether the chloride ion itself has a positive electron affinity). These are all chlorine ions, but none of them are chloride ions except Cl−. —Keenan Pepper02:50, 27 November 2006 (UTC)[reply]
Let's put it this way. As only one ion of chlorine, namely Cl- is relevant, it has its own name, namely "chloride". But the more common way of speaking is to call "chlorides" all salts with Cl-. Hence, both answers are correct. This is a general thing in the chemistry of ionic compounds: There all special names for all common anions, and these names are prefixed with the name of the cation (or just the respective element) to form the name of the ionic compound. Another anion involving chlorine is chlorate, see there for further examples. Also notice, that the suffix is significand: "-ide" means that the ion is just a negatively charged element, e.g. chloride, iodide, sulfide, "-ite" and "-ate" is used, when it is a compund anion with oxygen at different oxidation states, e.g. sulfite. sulfate, chlorate. Simon A.13:42, 27 November 2006 (UTC)[reply]
Just to repeat what everyone else has said Cl- is chloride and it's and ion.
Cl-, Cl+, Cl2+ etc are all chlorine ions but only Cl- is called chloride.
Well I drank buckets and buckets of milk as a kid and a young teen, and I grew to be exactly the same height as my short mother. I have extremely strong bones, tho. Which proves exactly... nothing. (Just saying it before someone else does). Anchoress08:06, 27 November 2006 (UTC)[reply]
I've never heard that before - got loads of milk and I'm not 'tall' so maybe the answer is no..
To explain the irony I read in that remark, milk is just one (possible) factor. If you've 'got the genes' to become tall but don't drink enough milk, you might not achieve your potential greatness. DirkvdM06:05, 28 November 2006 (UTC)[reply]
Milk builds stronger bones with calcium, and that may contribute to height by straightening your bones and such. ~ Flameviper 19:20, 30 November 2006 (UTC)
2)Question IF the sun would be bought nearer to the eatrh, the earth would have to move faster(more gravitational potential). Threr would no be any need for sudden movement (oscillation) of the sun to cause this force.Since ELECTRIC Field intensity can be modeled the same manner,Then why do we need to Move(oscillate) the Heavily charged sphere????
I'm trying to follow this, but I'm not sure you've got your model correct (or not sure I'm following you). The glow is caused by changing fields. If we had the big charged sphere it could have a constant electric field, like the sun has a constant gravitational field. In this sense though the Earth could be thought of more as a charged particle near the charged sphere (sun). This charged particle would experience an ongoing force caused by the electric field, just as the earth feels a constant gravitational force. --jjron 10:04, 23 November 2006 (UTC)
Well, if you have a tiny negatively-charged sphere attracting a large positive sphere, and orbiting around it, you wouldn't have to oscillate the large sphere if you brought it closer to the small one. But if you want to create gravitational waves, then you have to rapidly wiggle the sun, and it doesn't matter if the Earth is there or not. If you want to create EM radiation, you have to wiggle the electric charges. How does either situation relate to orbits?
3)What Im actually asking is with relation to the glowing tube light under the power line which only glows due to change in electric field intensity but electric field need not change(oscillate) for the electron to get attracted.
Um, yes. The electron will be attracted (or repelled as the case may be) without the field changing. --jjron 12:34, 24 November 2006 (UTC)
4)Well then why do we need oscillating electric field for the tube to glow when we dont need oscillating electric field for the electron to get attracted or repelled??
Because you want the tube to do something continuously, rather than merely do something once. If you have a static field, you'll polarize the tube, which may cause it to glow for a moment, but then nothing further will happen. You need to keep moving the electrons around to keep the glow going, and since they can't leave the tube you have to move them back and forth in it with an oscillating field. --Tardis17:32, 27 November 2006 (UTC)[reply]
I seem to recall from a documentary I watched ages ago that there was an island which arose in the Atlantic near Iceland in an extremely brief period of time, due to a volcanic eruption. I want to learn more now, but I can't for the life of me remember its name. The documentary said that its shores were full of ashes, but seeds from trees started growing within a couple months. I forget the exact year, but I think it was late 60s to early 70s, but I could be confusing this island with the volcanic eruption which was fought off by the icelanders. Sorry if I am confusing... Crisco 149206:05, 27 November 2006 (UTC)[reply]
Surtsey is indeed the most likely, although IIRC it's still above the surface. This sort of thing happens every now and again - in fact a new island was formed by a volcano off the coast of Tonga only a few weeks ago (see here). Another famous example was the ephemeral island (i.e., it has since sunk) of Ferdinandea off the south coast of Italy that - after it sank - was bombed by the US Navy who thought it was an enemy submarine. Grutness...wha?06:24, 27 November 2006 (UTC)[reply]
When did that happen? What war was going on? As for teh volcanic eruption fought back by the townspeople, which was that? Maaf, sorry for being a nag. 202.173.17.25006:29, 27 November 2006 (UTC)[reply]
That's expained in the article I linked. Ferdinandea rose and sank in the 1830s, but is still so close to the surface that the US mistook it for a sub during the crisis with Libya in the 1980s. Not sure which one was fought back by townspeople though (sounds like a tricky thing to do, too...) Grutness...wha?06:33, 27 November 2006 (UTC)[reply]
I heard it involved hundreds of firetrucks, and pumping water directly from the ocean. Not a simple task, to be sure. Makes Hollywood's "Volcano" a bit more comprehensible, n'est pas? Crisco 1492
Mais non, mon ami. Je suis né au Canada, et ma famille est Français puis Anglais. Besides, I need to practice my French so I don't forget it. Il n'y a pas beacoup de personnes qui peut parler la Francais aux Indonesia. hehe... aku sedikit bodoh... :P
Excuse my French, but shouldn't that be 'personnes qui peuvent parler'? And isn't Indonesia singular? Or am I now being stupid? DirkvdM06:15, 28 November 2006 (UTC)[reply]
"qui" is the pronoun here, and it's third-person singular. So "qui peut" is correct. (At least, that's what I think...I'm not a French speaker.) --Bowlhover17:05, 28 November 2006 (UTC)[reply]
The plural of a verb is determined by the noun, in this case 'personnes'. English doesn't know stuff like plural in verbs (count your blessings), so it's no surprise you got this wrong (even blessings have their flipsides). DirkvdM19:55, 28 November 2006 (UTC)[reply]
Hahaha should we move this conversation to the languages department? :P Sorry about my french, but its a little rusty after 2 months without next to no use. Most of the time here I'm speaking Indonesian, with some conversations with my host brother or some friends at school in English. There is only one person here I speak French with, and that was a while ago because French was easier for him than english, but now, since I can express myself in Indonesian rather well, I don't speak French as much. And Dirk, I do believe you are right about Peuvent, it would seem I forgot that it is the plural form of Ils and Elles. And yes, blessings do have flip sides... Indonesian has NO conjugations like English and French, indeed, the only thing i have to choose from (at least for now) is whether it is an Me- based, Be- based, or a passive voice verb, which begins with di-. I think thats probably the only reason I speak Indonesian as well as I do now, took about 2 weeks to get the grammar right, and now its just vocabulary (I hope :P) Crisco_1492
I'm pretty sure it has to do with cranial capacity, as well as facial bone structure, not necessarily body hair. However, the hair would be an evolution designed to protect them from the colder weather which they endured. Crisco_1492
See our article Neanderthal, in particular the section Anatomy. It gives a list of physical traits that distinguish Neanderthals from modern humans, but also states: "Nothing is known about the skin color, the hair, or the shape of soft parts such as eyes, ears, and lips of Neanderthals." Any depictions of Neanderthals as particularly hairy, as in this display of the American Museum of Natural History in New York City, are based on speculation. --LambiamTalk14:06, 27 November 2006 (UTC)[reply]
But a speculation that makes sense. Their whole bodies were built to withstand the cold. Then again, that may be because they were hairless. :) DirkvdM19:57, 28 November 2006 (UTC)[reply]
Concentric arrangement of radio antennae
When driving through Germany, I have sometimes seen from the autobahn strange structures of the following shape: Several (maybe around 30 or so) tall masts (some tens of meters tall) are arranged in a circle of maybe 50 meters or so in diameter, with wires around the circumferences at several heights. I'd guess that these horizontal wires are just to keep the structure stable, and the vertical masts look like radio sender antennas to me. They typically stand freely in the open counrtyside and are not very common. I always wondered what they were. A collegues just showed me this Google Earth location (which is near Augsburg, Germany), which seems to be a construction similar to the ones I notices. (He saw it from the train). Do you have any guesses? I do not think it to be a radio broadcast sender. Maybe some directional receiving antenna? Maybe even some installation for signals intelligence from Cold War times? Simon A.13:31, 27 November 2006 (UTC)[reply]
If you look up Google Image Search for 'antenna array' you might find some pictures of what you are looking for. They could be for powerful weather radars, etc. --Zeizmic14:49, 27 November 2006 (UTC)[reply]
I have just tried, and when I just wanted to reply to you that all the images I find are square arrangements, I clicked to just one more page of results, and there, I found that they are called "AN/FLR-9" (or colloquially: elephant cage) and indeed used for signal intelligence. It seems that we even already have an artcile on them: FLR-9. :-) Simon A.15:01, 27 November 2006 (UTC)[reply]
At first glance, I thought it might be a type of VHF omnidirectional range station though I don't know for sure. ~~
I can't find the French word for wart hog in my French-English-French dictionaries nor at the Office de la langue francaise translation site,but I see that the boar or sanglier looks like the wart hog.Have read nature.com, wikipedia and other web info but none mention the wart hog as being a sub species or relation of the wild boar so they seem to be completely separate species in Africa,Europe et al.Can anyone confirm that wart hogs and boars are related or not and how do you say wart hog in French? Cochon verrue-haha?
Are digital binoculars (we don't have an article, but Google shows plenty for sale) merely regular binoculars with an integral digital camera (that's what they look like in the pictures), or is there something more going on, like some digital magnification?--Shantavira15:50, 27 November 2006 (UTC)[reply]
Why is it that many plants have natural medicinal properties in humans? In many cases these properties are so complex that scientists take a long time to discover them, and then take even longer to synthesize their active compounds (if they are able to). For instance, aspirin is synthesized willow bark, the heart medication Digoxin is synthesized foxglove, a potentially huge new anti-inflammatory drug is being synthesized from Grains of paradise, etc.
I can't imagine that these complex interactions are coincidental, so there must be some connection. However, it seems unlikely that these properties were evolved for these specific purposes -- willow bark evolved for vascular tissue and to protect the tree. I don't see how having the odd animal nibble on the bark to aid their inflammations could have led to its properties being selected for.
Could anyone explain how such properties are evolved (no ID please)? Thanks! --George
"The entire plant is toxic (including the roots and seeds), although the leaves of the upper stem are particularly potent, with just a nibble being enough to potentially cause death." The mechanic of this toxicity is useful in controlled doses. However, rabits don't control doses. Asprin is actually a plant hormone. I'm not going to comment on the other drug - I suspect it has a similar effect - either directly poisionous due to dose, or a lucky coincidence. JBKramer16:08, 27 November 2006 (UTC)[reply]
Well there we go -- it's even harder to imagine a simple evolutionary mechanism if the plant is generally toxic. But you propose it's just coincidence? --George
Animal toxins may have mutated from digestive enzymes. I was able to find a number of suggest plant toxin branches - starting from chemicals that simply fought decomposers in small doses growing up, to bad-taste mutates to bad-effects. On willow bark specifically - [7]JBKramer16:49, 27 November 2006 (UTC)[reply]
I believe you're looking at it from the wrong angle. There is no specific reason or evolutionary mechanism that would make a plant have beneficial results on other animals. It's the other way around! Creatures on Earth developed their metabolisms based on plants (their primary source of food), so certain beneficial reactions are likely to happen. And then, this sensibility to that substance would be passed on to new generations.
For example, imagine creatures who have been eating a certain plant with a certain chemical compound for several generations. If few members of that species were particularly sensible to such chemical in a beneficial way, they would not only survive better, but would pass that beneficial sensibility to next generations, and the beneficial effects of that substance would remain in the species.
Now take that into account, along with the fact there are several millions of different species of plants, and that our species have been trying these in several different ways for thousands of years now, you'll see that a lot of these stuff was bound to happen.
Also, you gotta remember that a LOT of people died while trying to figure what was good to use and what was not.
Sure, that makes some sense, but it doesn't quite. Take the Willow bark example. Willow is a tree found in the northern hemisphere. Humans didn't reach Europe for quite some time after evolving into humans. Yet Africans are just as affected by aspirin as European humans are. Likewise, Grains of Paradise are found in a relatively small area in Western Africa. It doesn't really make sense that our whole species could have evolved dependancies on these plants found in such localized areas. -- George
Your wording is fine. It points out a common misconception: Too many people are of the opinion that Evolution has an end-goal. For example, Evolution looked at the shrew and said, I want a Human. What should I do next? Evolution does not have an end goal - it isn't even an entity that makes choices. It is merely the reaction of living beings to the environment. As the environment changes, living beings adapt to it. As you pointed out, a plant gaining beneficial chemical reactions will likely increase the lifespan of animals who are aided by the chemical reaction. The longer an animal lives, the more likely it is to reproduce and pass on the trait. --Kainaw(talk)16:26, 27 November 2006 (UTC)[reply]
I wasn't proposing a purpose, I was wondering what the selective value to such a trait would be. For evolution to occur, there must be a selective value for any trait. I think the selective value you propose relies on the evolution of the animal with respect to the plant, but it doesn't seem as if it could really work that way, given the willow bark example in my response above (humans pre-evolving a reason to eat willow bark before ever encountering willow bark?) . Anyway, thanks for the continuing discussion! :) -- George
There is such a thing as coincidence. All plants contain chemicals for their own evolutionary reasons, when humans eat them, some turn out to be useful, most I think are bad. With somethings like with diseases humans that respond best to local plants will be favoured, but with Aspirin it is probably coincidence that it has pain killing properties (after all so do cocaine and opium). Plants evolving due to humans needing their products would arrive with cultivation and selective breeding. Not sure how recent those were really done with plants though, especially for medical purposes.137.138.46.15516:53, 27 November 2006 (UTC)[reply]
You're still assuming that humans wouldn't be naturally sensible to the Willow bark until contact with it. This stuff was in our genes, and we just found out about the reaction later. Also, scientists nowdays test thousands of substances until they find one that has a certain reaction they're looking for. With years of such practice, we have figured certain characteristics that seem to be associated to certain reactions, but the process still relies on a bit of luck, so to speak. So again, this stuff is bound to happen. ☢ Ҡi∊ff⌇↯16:57, 27 November 2006 (UTC)[reply]
Yeah, that's probably the most logical answer. I guess all of life is using pretty much the same subset of chemicals and compounds anyway, making such coincidences more likely. Thanks for all the replies! --George
All drugs are poisons, it is simply a matter of dosage. Hence, if bugs are eating your bark, salicylic acid (Willow bark) will effectively control the bug population (I hav eno idea what the lethal dose is to a bug, but that would be the rational) similarly digitalis is a heart medication, but it is also a very good way to kill someone. All drugs are a matter of dosage and secondary metabolites are often produced for defense mechanisms. Occasionally it is fortuitous, i.e. plant hormones, but when it gets right down to it, there are really only a limited number of aproximate shapes to enzyme active sites, hormone receptors, etc., and so it isn't all that surprising that a secondary metabolite of a plant inhibits a human protein in the micromolar range.--John
It's not really a valid question. Turn it around and ask why certain chemicals in plants aren't medicinal. The reality is that life on the planet is all related. Therefore, chemicals that are found in different species will affect living creatures. There may be an evolutionary why aspirin is in willow bark but it's medicinal value may be pure coincidence. Look at it this way: decomposing human bodies provide nutrients and medicine for plants. What's the evolutionary reason for that? I would say none, just coincidence and basic tenet of simply being a living creature. We are all made of the same stuff. --Tbeatty04:20, 1 December 2006 (UTC)[reply]
availability of medicated stent
I would like to know weather medicated stent for right renal artery is available for usage or not? if available please
mail us place and the company name which produces it.
According to this link [[8]] they are manufactured by: Johnson&Johnson, Medtronic and ev3. Since you have been able to ask a question on Wikipedia, I'm hoping it's OK to let you chase down the addresses/customer contact numbers. Mmoneypenny19:02, 27 November 2006 (UTC)[reply]
Parabolic sound collecting dish
Please guide me to make a parabolic sound collecting dish. Which material is good for the dish? How far should the microphone be from the dish? What size is sufficient for the dish?
The material should be hard and rigid. Rigid plastics or alumin[i]um is commonly used. The microphone should be located at the focus of the parabola. I've heard that you can actually do a pretty credible job using a child's snow sledding disk (which is probably actually a section of a sphere).
The microphone should be placed on the dish's focal point. The size of the dish depends of the wavelength of sound waves in air that you're trying to capture. Humans can usually hear within a range from 20 Hz to 20 kHz. Since most of the lowest (below 300 Hz) frequencies are pretty irrelevant for speech recognition (assuming that's your purpose), a 60-40 cm dish should be more than enough for most of the hearable spectrum that you could use. The larger the dish the clearer will be the sound. ☢ Ҡi∊ff⌇↯17:57, 27 November 2006 (UTC)[reply]
On a similar topic - there are many radar dishes that went from a perfect parabolic dish to a tear-drop shape to decrease interference. Has the same been used in sound collecting dishes? --Kainaw(talk)18:20, 27 November 2006 (UTC)[reply]
You will have to define what you mean by "earth". The planet does not have a single temperature. Therefore, you can pick out temperatures of a single city that hasn't warmed much at all (or even become cooler) and use that as your source of "Earth temperature". You can pick out a handful of major cities. You can try to gather all the temperatures you can find. Do you want estimated ocean surface temperatures? How about places that we don't bother to check - should they be estimated? All in all, the concept of an "Earth temperature" is a problem for the Global Warming argument. Yes, nearly all sane scientists say the Earth is warming. However, there are those who cherry-pick temperatures to make it look like the Earth will be ball of boiling lava in 10 years. They make the reasonable argument hard to advance because only the nutjobs get major press. As for the sea level rising, it hasn't risen much - if any. Keep in mind that when ice that is in water melts, the water level goes down. So, as icebergs and ocean ice sheets (notably, the North Pole) melt, the sea level will go down. When ice on land melts, the sea level will go up. Combined, there is more ice on land than in the water. So, at some point, the water level should rise. --Kainaw(talk)18:34, 27 November 2006 (UTC)[reply]
(taken partially from MSL)Another thing to keep in mind is that finding the MSL (mean sea level) is much more difficult than temperature, as far as I know. MSL is the mean sea height, with reference to a suitable reference surface. Defining the reference level (http://www.pol.ac.uk/psmsl/puscience/index.html#1), however, involves complex measurement, and accurately determining MSL can prove difficult. Finding the MSL change involves comparing the local height of the mean sea surface with a "level" reference surface or datum, called the geoid. In a state of rest with absence of external forces (totally stagnant water), the mean sea level would be the same at every point on the Earth. The geoid would only deviate from the perfect sphere in this theoretical model with local differences in MSL from local deviations in the Earth's gravitational field. In reality, due to currents, air pressure variations, temperature variations, salinity variations, etc., this does not occur, and prevents certain verifiable long term averages from being calculated. Sea level measurements must account for the 228-month Metonic cycle and the 223-month eclipse cycle on the tides. MSL at the Pacific end of the Panama Canal stands approximately 20 centimeters higher than at the Atlantic end. The location-dependent, persistent separation between MSL and the geoid is referred to as "stationary sea surface topography," which varies globally by somewhere around ±2 meters. Doesn't that mean the error margin is 8 meters? Several terms are used to describe the changing relationships between sea level and dry land. When the term "relative" is used, it connotes change that is not attributed to any specific cause. The term "eustatic" refers to changes in the amount of water in the oceans, usually due to climatic changes. The melting of glaciers at the end of ice ages is an example of eustatic sea level rise. The term "isostatic" refers to changes in the land level, of land masses due to thermal buoyancy or tectonic effects and implies no real change in the amount of water in the oceans, although isostatic changes change the MSL because it is relative to the land. Ice ages cause isostatic changes. Ice on landmasses weigh them down, and push the land down. The subsidence of land due to the withdrawal of groundwater is an isostatic cause of relative sea level rise. X[Mac Davis] (DESK|How's my driving?) 15:59, 28 November 2006 (UTC)[reply]
Are you sure about the dropping water level in ice water? It seems to me that the ice is displacing its own weight of water, and once it melts (neglecting density variations in liquid water) it is still displacing that precise amount of water, since it is that weight of water. Shouldn't it have no effect? --Tardis22:51, 27 November 2006 (UTC)[reply]
Yes, I am sure. Ice is less dense than water - which is why it floats. Most of the ice is below water - very little above it. When ice melts, it becomes more dense - so it takes up less space. Taking up less space means that the overall water level goes down. Try it yourself - it's fun for the whole family! Put a bunch of ice in a cup of water. Mark the water level. Put another cup of water without ice next to it and mark the water level. When the ice melts, check the difference on each glass. The one without ice is there to see how much left due to evaporation. You'll find that the water level is much lower in the ice-water cup after the ice melts. --Kainaw(talk)23:19, 27 November 2006 (UTC)[reply]
Are you really really sure? I only ask because when we were doing this in school, I'm sure we learnt that the water level stayed the same. The amount of ice above water was supposed to be equal to the amount more space ice takes up than water. This is, if we are marking the water level, not the top-of-the-ice level. Skittle23:48, 27 November 2006 (UTC)[reply]
Detailed example: let's say ice's density is 0.9 g/cm^3. We throw a 1 g ice cube (that's 10/9 cm^3) into a cup of water. Water pushes up on it with the same force that gravity pulls down on 10/9 cm^3 of water. In our case, gravity applies 1 g of force to the ice cube. When the ice cube sinks so that 0.9 g of it is below the water's surface, the force of gravity (1 g) will equal the water's buoyancy (0.9 g of ice = 1 cm^3, 1 cm^3 of water = 1 g). At this point the ice cube stops sinking, so 1 cm^3 of water (0.9 g of ice takes up 1 cm^3) is displaced. When the ice melts, it will turn into 1 g of water, or 1 cm^3 of water. --Bowlhover04:32, 28 November 2006 (UTC)[reply]
So it displaced 0.9g of ice displaced 1 cm^3 of water (0.1 g was above the water line). When the ice melted, 1 cm^3 was replaced as water, therefore the water level remains unchanged. The density difference is why the ice isn't covered to the top, but it doesn't change the displacement. --Tbeatty05:30, 28 November 2006 (UTC)[reply]
You're missing one crucial element: while you're correct in saying that ice floating in the oceans doesn't (or barely) change sea level when it melts, not all ice on the Earth floats in the ocean. Quite large chunks of it are on land (Antarctica, most notably). When that stuff melts, it's a net increase in global sea levels. — QuantumEleven12:36, 28 November 2006 (UTC)[reply]
Can't argue with that, but I didn't claim global warming will not raise sea levels. I claimed that melting icebergs in the ocean won't raise sea levels. --Bowlhover01:24, 29 November 2006 (UTC)[reply]
The biggest error in global warming is correction of the heat island effect of cities. Measurements over many years are affected by the growth and size of the city. Global Warming does not mean warming happens everywhere and estimating the overall increase is very difficult if not impossible. Consider that the Albany, New York has been cooling while New York City has been getting warmer. Is this measurement error, correction error, or real differences? The next questions is whether warming will continue and is it related to human activity. There is a real question as to how warming affects water vapor in the atmosphere. Higher temperature means more capacity for water in the atmosphere but may also mean more clouds and therefore more reflections out to space. Tbeatty05:35, 28 November 2006 (UTC)[reply]
I don't think we know of the nature of the correlation between water vapour content in the atmosphere and temperature. Of course, generally, warmer planet equals more water vapour and increased albedo, meaning greater planetary reflectivity. Everything always seems to be in the goldilocks zone. :) NASA Link. The UHE is not as big a problem as some people say it is I don't think. All you have to do is rely on proxies and data stations out in the middle of nowhere. Although the whole "temperature is going up in the Northern hemisphere, and is still flatlining in the southern" is kind of freaky. There are more and bigger cities in the Nothern Hemisphere than southern, based on city radiation, however it is usually attributed to there being more land in the Northern Hemisphere. X[Mac Davis] (DESK|How's my driving?) 16:38, 28 November 2006 (UTC)[reply]
Clouds reflect Sunlight during the day but work as a blanket at night. That is something one can easily expeience in everyday life. I don't know how the two will balance against each other.
About whether the warming is caused by humans, is it a coincidence that scientists predicted it and then it happened? Next, people pointed out that the Earth has been in a global warming phase for thousands of years, so there is at least a natural cause. True, but is it a coincidence that shortly after scientists predicted a warming, it soon started happening really really fast? And I mean really really fast. As far as is known, temperature changes of a few degrees take place over at least thousands of years (which was already considered extremely fast), and that has indeed happened over the last few thousand years. But then it was predicted it would start to happen in hundreds of years and now it looks like it's happening over mere decades. That's about 100 times faster than 'normal'. DirkvdM06:49, 28 November 2006 (UTC)[reply]
I agree, but it is also true that during the hot months (i.e. what global Warming predicts will be longer and hotter summers), cloudy days are cooler than sunny days. As for scientists predicting it, keep in mind that they predicted cooling in the 1970's and it did cool. The reality is that science is a self-fulfilling prophecy. Scientists that make correct predictions get more coverage. It is not surprising that scientists that espoused global warming are credited with discovery and the field grows. 1000 monkeys on a 1000 typewriters may recreate Shakespeare at some point but I hardly think that one monkey should be credited with prescience and intelligence. Let alone, giving credit to me for predicting a monkey might recreate Shakespeare.
Do you remember the compelling global cooling scenario? Clear cutting forests created large open areas that reflected vast amounts of sunlight which caused global cooling. This in turn cause the ice caps to grow which in turn reflected more sunlight and the positive feedback loop was created. Very compelling and logical. This coupled with heating oil shortages and relatively cold (though not historically cold) 1960s/1970s (every year was cooler than the next with Blizzards regularly on the news). Not unlike the global warming positive feedback loop that is being espoused today. The problem is that warming won't be continual. The results? keep the hype but change the name to "Global Climate Change" or "Abrupt Climate Change". This allows any type of weather to warrant political action. I personally am very sceptical about the dire consequences. I think the earth is much more resilient than we give it credit.
Scientists like to look at trends. The Earth MSTA has been going up for about a little bit. Science is all about predicting, but in climatology we're not there yet. When the temperature started going down fractions of a degree the scientific consensus was global cooling. Trends, are all we have in predicting. We're trying to figure out what happened before, and what is happening now. The IPCC's Third Assessment Report (I have it right here!) and it states "Climate models now have some skill in simulating changes in climate since 1850." We just guess what is going to happen, based on trends, based on the time scale, and we're also trying to figure out what happened before. Climate systems are nonlinear and chaotic, then it can be difficult to predict the future. [9][10] This isn't like a "how fast will the bowling ball be going one meter above the ground if it was dropped from five meters" question. Also note that proxy-deriven data is less reliable than human-taken datas for obvious reasons. About the clouds, usually just the albedo is looked at, and we have gas isotope ratio proxies for those. It has been going up as well. How much, what effect does it have, and how strong is that effect? Debatable. I wish we just knew. That would be easier. X[Mac Davis] (DESK|How's my driving?) 15:59, 28 November 2006 (UTC)[reply]
Yeah yeah, global warming is just a big guess, I can't argue with that. But even the most conservative guesses show Earth should warm up after doubling the atmosphere's CO2 level. It's how much it will warm up that's not for certain. --Bowlhover16:52, 28 November 2006 (UTC)[reply]
The problem is that scientists want to have near absolute certainty but politics can't afford to wait for that sort of thing. If there is a strong indication that things might go horribly wrong then action has to be taken before we can be certain. And by now it's so obvious that no-one can miss it. I don't know about elsewhere, but in the Netherlands the 10 hottest years since 1901 all fall in the last 17 years [11] and unless the temperature tkes a dive over the next few days, this autumn will become the hottest in 300 years. The previous recordbreaker was 2005 (shared with 1731). This year also had the hottest august in 300 years, the hottest july, the hottest september, the second hottest october and probably the second hottest november in 100 years. You could say that that is just this year, but most hottest months since 1901 fal in the last two decades. That is becoming more than a hint. But like I always say, don't trust me. Trust the scientists. If they don't know, then who does? DirkvdM20:24, 28 November 2006 (UTC)[reply]
In my opinion, it is comments like the previous one that hurt the global warning message. For every person who says it is hotter than ever where they live there's a person who can say the opposite. We just had the first snow-game in Seattle last night. It snowed in Charleston, SC last week - in November! Global warming isn't about your personal city having the hottest trend in 100 years. It is about global warming. One effect of global warming is radical weather patterns - the kind that send snow too far south and heat waves too far north. Perhaps the "warming" should be dropped from "global warming" so people can get over the concept of "If I look at this here thermo-dilly-bob and it'n says it ain't too hot, then there ain't none that there global warming stuff goings on." (Yes, I grew up around plenty of backwards country folk) --Kainaw(talk)20:53, 28 November 2006 (UTC)[reply]
"The problem is that scientists want to have near absolute certainty but politics can't afford to wait for that sort of thing." Umm, Dirk, is it "say-the-opposite-of-what-you-mean day" already? I thought that's on the 31st! --Bowlhover01:24, 29 November 2006 (UTC)[reply]
Before spending billions of dollars on reducing global warming, I think you'd want to be nearly certain that the money isn't going to go to waste. In science, if a theory has a 70% chance of being correct, scientists will say "ok, this is probably true, though we'll need to do some more experiments". --Bowlhover03:52, 30 November 2006 (UTC)[reply]
But in politics a 70% risk of climate change should be an incentive not to wait for further research but take instant action because the potential losses are huge. Crops will start to fail. How many and how seriously may not be certain, but there will be losses and those have to be weighed against the cost of intervention (if we ignore the human tragedy for a second). But this intervention does not have to cost money. It can save money. After all, saving on exhaust fumes means saving on oil expenditure. Do the same thing with less fuel and you've got a win-win situation. Traffic is a good example. Use strict laws to make people drive at a steady pace and in unison and that will in itself save fuel. It will also reduce traffic jams and thus irritation, fuel and (working) time (=money) wasted. Win-win-win. A nice side-effect is that it can save hundreds of thousands of lives per year. Often young lives, that money has been poured into but not yet given its full yield. So more money savings. Win-win-win-win. What's stopping us? A sense of 'freedom' in how we drive our cars. But if that freedom gets you stuck in a traffic jam, what is it worth really? DirkvdM09:31, 30 November 2006 (UTC)[reply]
Snow in the Seychelles? That is indeed quite extraordinary! :) I bet they danced in the snow. I wonder what kind of dance they did.
But seriously (before SCZenz deletes me again), you mention cities. I mentioned a country. I admit that I went into a little too much detail with the months and autumn. But you have to agree that all 10 hottest years since 1901 falling in the last 17 years (and almost all 10 coldest years falling in the first half of the century) is a pretty serious (and convincing) trend. But I agree that radical (and less predictable) weather is a much more serious threat. The effect that may have on agriculture should really scare the shit out of people. Here in the Netherlands there is a lot of stress on rising sea levels (and thus global warming) for obvious reasons (euphemistically called 'getting our feet wet'). But increased rainfall in Central Europe will come our way through Rhine and Meuse and that combined with a high sea level and more fierce storms should also impress the Dutch (North Sea flood of 1953 - I'm surprised I haven't heard any references to that yet). DirkvdM21:17, 29 November 2006 (UTC)[reply]
Isn't it a bit far fetched to suggest that a natural environmental condition could have been affected so quickly by human actions? A few hunters going after a bunch of birds and geese isn't exactly going to affect a thousand year old cycle of extinction/speciation on the earth, I mean there were extinction events thousands of years before there were ever any human beings around, and now there still are, obviously there haven't been human beings living there the whole time doing it, so why attribute it to human actions? It seems like this was more of an excuse for Clinton to get the federal government involved in the personal affairs of Americans, then a serious study. So the question, in light of current science, does Clinton's theory of 'Endangered species' still hold water?--Gomer pylon18:22, 27 November 2006 (UTC)[reply]
You might ask this question of the whales. I think they could enlighten you on the effects mankind can have on some species.
I wasn't aware that Bill Clinton was a population biologist, or that a theory of endangered species was attributed to his work. Good on him, though, if he's been diversifying.
Human-driven extinctions have been around for a long time—some are the direct result of human hunting/trapping/poisoning/eradication, while others are the result of the effects (deliberate or otherwise) of introduced species carried (again, deliberately or otherwise) by migrating/trading humans.
You're going to have to be a bit clearer about what specific question you're asking; consider phrasing your question as a question, rather than as a thinly-disguised conspiracy theory. TenOfAllTrades(talk) 22:09, 27 November 2006 (UTC)[reply]
Dunno about Clinton, but you said it - extinction has always been going on, due to loads of causes. Humans are just one such cause. But humans are pretty powerful (technology) and numerous (five billion of just one species our size is quite excessive). A new factor is climate change. Species that are more or less specialised will have to move to new areas that have the right temperature (in general towards the poles or uphill), but other condiditions there might not (probably will not) be right for them, in which case they may not be able to survive, depending on how versatile they are and how fast they can evolve to adapt. And some will not be able to move so fast, such as plants, which often move at just a few metres per generation. DirkvdM07:05, 28 November 2006 (UTC)[reply]
If humans are unnatural than where did we come from? The Native Americans are largely regarded as very close to nature, and about as easy on nature as you could get before they where whitemanized. Native Americans around Yellowstone didn't like the "old-growth" forest very much at all; the forests may look astonishing and impressive, but they're dead landscapes for game. They set fires, making sure the forests burned down periodically. They made sure there were only islands of old-growth forest in the midst of plains and meadows. The forests that the first Europeans saw were hardly "primeval." They were cultivated—the Native Americans changed them to their liking. Its not surprising there is more old-growth forest today then there was one hundred and fifty years ago. A leading theory says that early Native Americans hunted mammoth and other large animals to extinction, they burned forests and changed the environment to suit their purposes. [12][13][14] Humans have the ability to adapt to all kinds of things, using not only their DNA, but their minds. Plenty of animals change their environment, beavers and termites come to mind. They aren't drastic, or close to the scale you say. Well, a few beavers controlling a river sounds a bit off scale, but it is natural. Beavers have been doing it for so long, that it becomes part of the environment, as if it wasn't before. It's normal, and everybody adapts to your adaptation. Coral? Coral can be called "slow" but it is such a weak organism, and it changes the enivronment so much. The Great Barrier Reef is host to uncountable amounts of other organisms, as well as affecting ocean currents. X[Mac Davis] (DESK|How's my driving?) 17:02, 28 November 2006 (UTC)[reply]
I severely doubt the native american population was ever large, widespread or co-ordinated enough to hunt anything to extiction. And humans are unatural now, whatever you get told. If we were natural, if our society was completely razed, we would just put it back up, like an indian would have, if his village was destroyed, he would catch a bison, and make a new teepee or whatever, civilized humans are completely incable of survival without there support system, if new york was razed, half of them would have probably died by the end of the first week. PhilcTECI19:02, 28 November 2006 (UTC)[reply]
It doesn't take a very large human population to have a dramatic effect on large animals, as there aren't very many of them, either. As for human's causing extinctions, there is absolute proof of this in many cases, such as the passenger pigeon. StuRat08:11, 29 November 2006 (UTC)[reply]
Your original argument contains a logic flaw, paraphrased as "since other things cause extinction, there can't possible be more causes, so humans can't be a factor". Just because A causes C, this does NOT mean that B cannot cause C. This illogical argument is popular with anti-environmentalist in all areas:
Since methane, carbon dioxide, ozone, etc. are also produced by natural processes, we can produce any level we want and not worry about the consequences.
Since global temps vary naturally, we can ignore any signs of global warming.
Since radiation also occurs naturally, we don't need to worry about nuclear contamination.
Right, it's the scale that counts. A species the size of humans doesn't usually go beyond a few million. We've got a thousandfold of that. Also, humans are part of nature. But in nature shit happens too. All the time, actually. We need to defend oursselves against that, not make it worse and say "oh, it's ok, that's nature." That goes for the climate as well extinction. We can use biodiverity to our advantage, such as new crops when old ones fail. It's not just 'that cure against cancer somewhere in a rainforest' that talk about this is often limited to. DirkvdM09:49, 30 November 2006 (UTC)[reply]
Humans do have a direct effect on the extinction rate, and extinction selectivity of species. Briefly put, where humans go, big animals die: escpet the ones we domesticate. Ask the big flightless birds of polynesia...actually they are all dead. Human induced climate change and environmental destruction is also leading to a massive extinction. There have definitely been bigger extinction events, and ones that wiped out almost everything, and the planet survived. But it lost a lot of evolutionary lineages each time. Also, never, in any extinction event, have large animals pulled through. It doesn't look very good for us. Gradual elimination of members of the food chain is like playing Jenga. It doesn't look like the chain is suffering any damage until you pull out the key peice and it all comes tumbling down. The African Savannah is a good example of modern human effects on local extinction. A change in agriculture brouhg in by Europeans in the 19th century led to the halt of the farming of traditional crops and led to the introduction of European crops. This of course caused a large change in the local ecosystem which led to collapse. Hence the fact that parts of Ethiopia, Sudan, and Chad which were once able to sustain reasonably large populations are failing: soil quality is falling, and not enough local plants to replenish it. Greater populations on limited resources are also leading to major environmental pressures. This is going on all ove rthe world.
Note that there is another factor at work - overpopulation. The great famine in the Sahel was in part due to modern medicine keeping people alive, but people not responding to that by getting fewer children. The ecosystem was sufficient to support the former population, but not the new one. Alas we can do little about overpopulation in the short run, even though it is the major cause of the disruptive effect of humans. So in the meantime we need a smaller impact (footprint) per person. Which is not to say that that will plunge us into poverty. We just need to let go of the notion that we have to keep on accumulating more wealth despite the fact that we already have more than we need. DirkvdM08:07, 1 December 2006 (UTC)[reply]
How heavy would a 100x100x100metres cube be on earth if it had the density of the average human body? - Keria18:46, 27 November 2006 (UTC) P.s.: not psychopathic homework![reply]
Figure that humans have just about the same average density as water—we float, but just barely. You can work from there; you should hit something like Dragons flight's answer. TenOfAllTrades(talk) 19:11, 27 November 2006 (UTC)[reply]
Depends on if your human meat cube has air filled lungs and how much fat, they're both considerably less dense then water. Human meat cube, I like the idea of that! Can I be involved?? ;) Vespine23:22, 27 November 2006 (UTC)[reply]
Note: this is the science questions page not computing...
Fossils
I have had a good look at pictures of the fossils found in the Burgess Shale and the interpretations made of them by science illustrators. I find them fascinating. Could you point to other paleontological and archeological discoveries showing fossils different from the Burgess Shale? Any link to illustrations of unusual fossil animals would be very much appreciated. Thank you - Keria22:55, 27 November 2006 (UTC)[reply]
Once you have used up Wikipedia, it's time to move to Google! Rather than fossils, I would concentrate on the beginings of life, life in the Pre-Cambrian, Cambrian and Paleozoic. There are a lot of resources, and full 3-D illustrations. --Zeizmic12:58, 28 November 2006 (UTC)[reply]
If I breathe out as much air as possible, I still float in the pool. Skinny friends of mine sink. (Yes, I need to lose weight.) Skinny friends swim just fine. But if we were stuck out in the ocean without any flotation devices, they might tire and die first. --Wjbeaty04:55, 30 November 2006 (UTC)[reply]
Remote-controlled phone--will these parts work?
As a follow up to an earlier question, I have a speaker phone that I'd like to be able to control remotely. I'd like to hook an RF receiver up to the points on the PCB (inside the phone) where the buttons touch. I have two buttons I'd like to make use of:
The on/off button
The 6 button
The buttons work like the keys on most keyboards--when a key is pressed, a little dot on the bottom of the membrane under the keys hits the exposed paths on the PCB, completing the circuit, and the phone registers a button press.
So after hunting around for a few parts, I came across these two items: An RF receiver [16] and the accompanying transmitter [17]. My question is: With the receiver, would it be a simple matter of connecting the two relays on the receiver board to the two pairs of points on the phone's PCB (and then supplying power)? The description for the receiver mentions it has two relays, so would this mean that, when it receives a signal from the transmitter, the relay would then complete the circuit and mimic a button press on the phone? The relay article seems to indicate it does (and each relay can operate in pulse mode, where a pulse would mimic a press-release of a button), but I thought I'd ask here just in case.
Seems you have found the ideal hardware for the job 8-). It is IMO a simple matter of connecting the Normally Open contacts of the relays on the receiver board to the two pairs of points on the phone's PCB. Whether pulsed operation is long enough to open the front door, you will have to try out.(or do you dial 6 to do this-- I cant remember) Also, you need some power for the reciever. You may need to use a battery for this to avoid messing with the phone. In fact I would recommend that you do as this will give you complete isolation of your kit from the phone companies, and therefore increased safety!--Light current00:42, 28 November 2006 (UTC)[reply]
The product page recommends a 9 volt adapter, so I may try to go with a 9V battery if I can. Though as this is a custom job, there's no clean battery compartment in which to set the battery, so we'll see (on the other hand, the receiver board has its own DC 9V in). I hit '6' to get in, and it seems that the relay will stay open for 0.5s, which should be plenty. Once all hooked up, it should be button#1 (pickup), (talk), button#2 (dial 6), button#1 (hangup). Thanks. --Silvaran02:39, 28 November 2006 (UTC)[reply]
A friend in Australia says he heard a news item on the radio about a massive solar flare (in the past couple of days) that disrupted electronic transmissions on earth. I can't find anything about this after searching news.com.au, google, and Wikipedia. Does anybody know what he might have been referring to? --199.3.116.523:25, 27 November 2006 (UTC)[reply]
Thanks. But, if it disrupted electronic transmissions in a significant way, as my friend claimed, why can't I find anything about it from mainstream news sources? --199.3.116.500:55, 28 November 2006 (UTC)[reply]
I think the problem here is disrupted in a significant way is very subjective. To a scientist, significant may mean it measured significantly on some instruments that read radio interference. To a layperson, significant may mean their Foxtel didn’t work for a day, I'm guessing it was more like the first type of significant. Vespine03:46, 28 November 2006 (UTC)[reply]
Can someone please name Biological(Living) pollutant in human waste. I would also greatly appreciate to know some of the problems it causes. I would like an answer by Wednesday the 28th of November 2006 at 11:30 am NZST.
Many thanks, and ,once again, ANY help would be greatly appreciated.
Cheers:
CODY NIXON-MEAD
WHANGAREI BOYS HIGH SCHOOL
WHANGAREI
NEW ZEALAND
what is better for you and what is the quickest way to lose weight? by working out or by not eating or by dieting
Arguably working out. It'll improve your cardiovascular health as well as allowing you to reduce your weight, but depending on how much you eat, you might have to diet to a degree as well. Sockatume04:37, 28 November 2006 (UTC)[reply]
"If requesting medical advice ask a Doctor instead." Methods of weight loss qualify as medical advice. Go see your doctor please. We are not responsible if you starve yourself to death because someone on Wikipedia suggested it. pschemp | talk07:07, 28 November 2006 (UTC)[reply]
Ah, common, saying that excercise will reduce someone's body weight is medical advise? You've got to be joking. And unless you've got some health problem fasting is no serious threat. Muslims do it every year (and some Christians may still, too). And I've done it once, not eating at all for five days. In India it is said that cleans the body. One has to make sure to drink lots of water, though. And the effect will be very slow. I lost 10kg that way, but that took several months. I suppose one important reason was that my stomach had shrunk and therefore it was easier for me to eat less without getting hungry. DirkvdM07:27, 28 November 2006 (UTC)[reply]
Yeh, I have to agree, If your going to be perdantic, you could say this is a reference desk, not a random facts hub, and reject all questions that arent asking to be referenced to an article. Bu luckily, most of us arnet that bad. PhilcTECI18:52, 28 November 2006 (UTC)[reply]
Not eating will lose weight the fastest, but it's not healthy at all. If you want to lose weight you have to use more calories than you're eating which, unfortunately for you, means excercise. It doesn't have to be traditional excercise in a gym, though. You can take the dog for a longer walk, or do less driving and more walking. - Mgm|(talk)08:54, 28 November 2006 (UTC)[reply]
Oh, and a reminder quickly and healthily are usually mutually exclusive when it comes to losing weight. Your body will have less trouble adapting if it goes slow. - Mgm|(talk)08:55, 28 November 2006 (UTC)[reply]
what are the factors that affect the structure of a community?
Define factors, structure and community and please sign your posts:) If i was to take a guess as to the things that you mean I would say climate, education, wealth and culture are some significant things that affect the structure of a community. Vespine06:06, 28 November 2006 (UTC)[reply]
May not be. There are electronic cams which don't have any rotating parts. The opening and closing are controlled electronically for accurate timings. I suppose that the F1 racing cars us this kind of cams -- WikiCheng | Talk15:02, 28 November 2006 (UTC)[reply]
A PDN two bearing arrangement housing (110mm shaft diameter) were installed on underground water pump for a mining industry. The engine that drives the shaft expirienced a 170% over-speed for 30minutes. This resulted in a partial meltdown of the bearing and unfortunately melted the bearing to the shaft. An inspection revealed a destroyed bearing and minimal damage to the shaft. But space is limited, the housing cannot be removed and the pump impeller cannot be removed to remove the shaft.
THE PLAN NOW IS TO REMOVE THE BEARINGS FROM THE HOUSING AND REPLACE THE BEARING WITH SPLIT CAGE BEARING MANUFACTURED BY COPPER.
Well, I'm not going to do your homework for you unless I get your grade too. But here are some things for you to think about that will set you on the right path... a normal bearing is a single piece shaped like a torus, right? Now since you can't remove the pump or the impeller, per the problem statement, you won't be able to install the new bearing over the pump shaft. You need access to one end of the shaft in order to slide the hole in the center of the bearing over the shaft, right? So what is a split bearing? Did your instructor or your textbook cover that? Can a split bearing maybe be made out of two halves, which are assembled in place? Could that be an advantage of a split bearing in this case? As to why it is copper, think about copper for a bit, it's pretty soft, right? Like you can bend a copper wire, but a steel wire would be a lot harder to bend, wouldn't it? The pump shaft is made of steel, so why would the bearing be made out of something softer? 192.168.1.1 5:38am, 28 November 2006 (PST)
Two girls told me I have nice shoulders. What the hell does that mean? I'm assuming it's not my idea of nice as in "large, round, and tear drop-shaped." Muscular? Or does it have to do with the infamous torso width:waist width? Or is it purely psychosomatic? X[Mac Davis] (DESK|How's my driving?) 15:44, 28 November 2006 (UTC)[reply]
I think only they can answer that, as I have not found a picture of your shoulders. Post a pic and perhaps someone here will be able to help.--Shantavira15:51, 28 November 2006 (UTC)[reply]
They were probably trying to lure you back to their lair to suck out your blood, since most women are blood sucking vampires. Next time this happens, make a sign of the cross with your fingers and run for your life! ;)Vespine22:00, 28 November 2006 (UTC)[reply]
Anyone know how much energy it takes to make and erect a wind turbine??? How long does it take until they have made up for this energy used? --86.139.127.2916:29, 28 November 2006 (UTC)[reply]
It would depend a lot on the exact make-up of the wind turbine and its tower. You'll need copper and steel for the alternator, glass-reinforced plastic, carbon-reinforced plastic, wood, or aluminium for the blades, various materials for the gears, bearings, and housing, steel or wood for the tower, and copper or aluminium and more plastic for the connecting wires.
A microturbine mounted on an exiting building obviously needs less material than a turbine on the scale of the Altamont Pass turbines, but also produces less energy. It'd probably be pretty difficult to calculate the exact energy payback time, but if you choose one or two configurations, maybe we can take a SWAG at it.
I'd say it'd abe very difficult to come up with a precise ansswer. The problem with comming up with an answer is in part the problem of where to define the limits of a system - in this case the limits of what constitutes the "system" making wind turbines. Do you just count the cost of the manufacturer? How about the cost of building the factory? The tools? Mining ore and transprort? Educating and the welfare of workers? Installation? You need to define the system so it has an end, but as it is a product of society the absolute true cost is nearly incalculable. Another problem is defining what is a wind turbine. I imagine it costs more in energy to build a 3MW tower turbine than a 100W wind jig I can put on my shed - and they will have different efficiencies in power production. A specific turbine will vary in power generation efficiency based on the strength of the wind, current state of maintenance, humidity and quality of installation. And then do you only count the power generated or do you deduct for losses in the utilization of that power? So, the S.W.A.G. approach is probably the best you can do - but you'll still need to define your limits and terms. Robovski03:34, 29 November 2006 (UTC)[reply]
"Market" for leptin
I suppose there could be a market for synthesized ghrelin because a lot of people are overweight and something that induces satiety could aid in weight loss for such people. But could there be a market for leptin? I'm thinking maybe for wasting disease such as end stage cancer or AIDS. Are there more "markets" than these two for leptin? Jack Daw16:46, 28 November 2006 (UTC)[reply]
First, I think you have your hormones mixed up. Leptin stimulates satieity (reducing hunger) and ghrelin turns of that satieity signal, effectively stimulating hunger. With the exception of patients with congenital leptin deficiencies, increasing leptin in the body does not typically alter eating patterns in the long term, with the added problem that exogenous dosage can lead to leptin resistance. Ghrelin may well be an effective antianorectic, but there are many other chemicals which already do this. Also, reduced feeding is not typically due to reduced hunger, but the presence of nausea (as in the AIDS and ES Cancer patients you mention above), or another inhibitory influence (as in anorexia nervosa). Tuckerekcut01:13, 29 November 2006 (UTC)[reply]
detailed information regarding the physics of webbed feet in birds, especially as it relates to birds which skim on the water as it lands
Dear Wikipedia,
I am looking for more detailed information about the physics of webbed feet in birds, especially as it relates to bird’s which skim on the water as it lands.
The type of information I am seeking has to do with the relationship of the birds weight to the surface area of the feet. Knowing enough about physical science, I assume there must be an overall relationship to webbed feet birds that use the webbed feet for skimming on the water when they land in the water to the total area of the webbed feet. Of course, the webbed feet also provide greater ability for locomotion on and within the water, but as any bird will tell you, webbed feet are very “handy” to use when landing ON the water.
Can you guide me to information regarding the mathematics, relationships, physics, or any empirical studies done on the ratio/proportions of webbed feet to body mass of birds which skim on the water when landing? If only such information regards propulsion on and within water…then I’ll take that.
Thank you
Carson
tb124 at earthlink.net
I sent an E-Mail to your address with the best available answer given due to the necessity of the bird, and considerations of their feet. Most birds are private in the matters of their webbing, yet the answer should be enough to fulfill the curious.
The abuses of silicates
Silica is the basis for many things positive, yet the introduction into the human body has no advantages. There are the biblical aspects of "'gates of death"' that are computer chip implementations which I have deemed the new form of enslavement within America, and there is the base element of most medications Si. My question is this, " How can any person of science, who has achieved the ability of reason based upon fact, believe silicates are positive in the foods and medications when they are plastics, rubbers, glasses, and rocks? I would appreciate an unbiased opinion that has been formed through research without predjudice. John Wesley Blum
The second clause of your second sentence is unintelligible, yet at least linguistically your question seems to depend on it for sense. Can you clarify what "there is the base element of most medications Si" is intended to mean? Then maybe we can tackle your question. alteripse19:31, 28 November 2006 (UTC)[reply]
(edit-conflict} Coupla major problems obviate the need even to do research yet:
Technical issue: computer chips are not usually made of silicates.
Huge logical falacy: your logic would also support avoiding oxygen (present in plastics, glasses, rocks, maybe some synthetic rubbers), carbon (present in plastics, rocks, rubbers), and hydrogen (present in plastics, glasses, rubbers, rocks).
Faulty premise: silicon is not present in most medications, or if it is, only as an inert filler that could easily be avoided by reformulation.
You'd be better off avoiding germanium and other 'rare earth' elements. Silica one of the most common elements in the Earth. Silica is no more inherently evil than any other thing. It's a thing. It can't be good or evil of itself - it's like a gun or a pen or the air your breathe. Franlkly, it's not to God if we are enslaved on Earth or not - it's all a part of having free will in the face of God's omniscience and omnipotence. If you believe he knows all and sees all BUT that he wants you to have free will then he lets man do unto man. If he thinks he has all of this and he DOES care about what we do to each other and intervenes, then you have no free will and what will happen will happen. QED it makes no difference in this world in respect to god.
Why does burning natural gas produce 40% less CO2 than burning coal?
Well, Natural gas is mainly methane, that contains an atom of carbon and four atoms of hydrogen. Coal on the other hand is mainly just carbon, with a small amount of other stuff thrown in. When a molecule of methane burns the by-products are an molecule of carbon dioxide and two molecules of water, when coal burns the majority of the by-products is just carbon dioxide. Vespine21:46, 28 November 2006 (UTC)[reply]
Ah, the energy in coal is stored in carbon-carbon bonds, not carbon-hydrogen bonds. I was forgetting the lack of hydrogen in coal. Thanks. I hadn't realized that natural gas was such a supremely better fuel in terms of greenhouse gas production.--206.170.183.6022:44, 28 November 2006 (UTC)[reply]
boron
what year was it decoverd?
who decoverd it?
how many common isotopes are in it?
is there any safty infomashion on it?
any facts on this element?
Wikipedia is an encyclopedia. Type boron into the search box and click the Go button. You'll find an article with plenty of information on boron much faster than asking someone else to read the article and answer your questions. --Kainaw(talk)19:52, 28 November 2006 (UTC)[reply]
Surface area of a lightbulb
I'm doing a presentation on Thursday about processor heat dissipation. I'd like to make the comparison to a standard lightbulb (60 or 100 watts). To do this, I need to know - what is the surface area of a standard light bulb? Raul65420:50, 28 November 2006 (UTC)[reply]
Note - according to this, your ordinary house light bulb is type A-19.
If you take a piece of paper that's 20 by 10 cm, you can completely cover the bulb with some overlap. So, the area is less than 200 cm2. Perhaps say, 150 cm2? --HappyCamper22:23, 28 November 2006 (UTC)[reply]
If you don't have any calipers handy, just wrap a measuring tape around it to get the circumference, then find the diameter by dividing by pi. StuRat07:15, 29 November 2006 (UTC)[reply]
Equations
A)need help to solve: Fe(s)+O2(g)->F2O3(s)
B)CH4(g)+O2(g)->CO2(g)+H2O(g)
For A) you need the same number of Fe and O on both sides. In order to do this, look at what you have got:
Left side - 1 Fe + 2 O
Right side - 2 Fe + 3 O
Lets start with the O. The lowest common multiple of 2 and 3 is 6. Therefore it would be a good starting place to make it so that there are 6 O on each side. Now you are left with: Fe + 3O2 -> 2Fe2O3
Now, do the same with the Fe. You now have 4 on the right and 1 on the left. Therefore the answer is: <Removed answer. Please don't give the answer to homework questions, just guidance on how to get there :-) Skittle22:43, 28 November 2006 (UTC)>[reply]
For B) you have:
Left side - 1 C + 4 H + 2 O
Right side - 1 C + 3 O + 2 H
Try balancing the H. You now have: CH4 + O2 -> CO2 + 2H2O
Solve? Perhaps you mean balance? Just see if the numbers of atoms balance on both sides of the arrow. In other words, just try adding constants. Look at how others answered. Try this one yourself, C6H14 + O2 --> H2O + CO2. (Complete Combustion of Hexane). 74.102.89.24101:20, 29 November 2006 (UTC)[reply]
IANAI but I think Fab is the antigen binding fragment of the antibody, while Fv is the variable domain (and therefore a fragment) of Fab. Both Fab and Fv are used in antigen binding experiments.Mmoneypenny00:55, 29 November 2006 (UTC)[reply]
why is it called annihilation of matter when Dalton's theory state that All matter is composed of extremely small particles called atoms, which cannot be subdivided, creted or destroyed. would that contradict each other. Dragonfire 73422:54, 28 November 2006 (UTC)[reply]
Dalton's theory is chemically correct, but quantum and atomic theory has superseded it. Atoms CAN be destroyed by atomic reactions. See atom bomb if you need convincing. Technically, they aren't really destroyed as much as change state into energy. Vespine23:04, 28 November 2006 (UTC)[reply]
Mostly 'cause Dalton hadn't ever heard of Albert Einstein. We now know that matter and energy are equivalent and can be interconverted according to the famous relation E=mc². However, for practical purposes in everyday life (and chemistry) Dalton's approximation is very nearly correct. It's only when you get into the realm of nuclear physics that you start getting appreciable amounts of mass converted into energy—up to about 1% of the mass in a hydrogen bomb, and all of the mass in the extreme case of a matter-antimatter annihilation. TenOfAllTrades(talk) 23:11, 28 November 2006 (UTC)[reply]
battery
How does electrolysis differ from what goes on inside a battery?
No, it doesn't, not unless you hook it up to another power source and run current through it the wrong way. Electrolysis is the opposite of electric power generation in a galvanic cell (one module of an electric battery). Electrolysis converts electrical energy into chemical energy; a galvanic cell converts chemical energy into electrical energy. —Keenan Pepper04:58, 29 November 2006 (UTC)[reply]
Finding a table with the charge of Ions
Hi there,
Im in a high school chemistry class and we are doing a lot of work with combining ions and compound and what not. Nothing too difficult really. I am looking for a very helpful resource. I noticed that somebody had this very useful table which contained many common ions and their charge and formula and it was small enough to fit on a notecard. Our chemistry teacher allows one notecard on tests sometimes and that is a very handy resource. Iv been searching for a while and decided to drop a line over here to see if anybody knows of a page or table such as this. Thank you in advance!
I was wondering how one could find the amount of valence electrons in a particular element, and how valence electrons are different from just normal electrons.
Most people are left or right handed, legged, eyed, etc...Can a person really have a prefered EAR? Of course, I`m presuming no pathology is involved here. And, I don`t mean 'prefered' as a regular preference. I mean 'prefered' in the sense that the person truly, consistently UNDERSTANDS things better, not hears better. Remember, no pathology present. Nothing like earwax, or proximity, anything like that. Personally, I have a very difficult time following instructions, remembering numbers, and such, when holding the telephone to my right ear during telephone conversations. No such difficulties while using my left ear. To the best of my knowledge, each of my ears is equally 'sensitive'. I don`t think I favor one over the other for things other than "close" hearing. i.e. phone. Is anyone aware of any study/ies having been conducted that has/have produced any palpable and/or meaningful results? Could there be a 'left-brain right brain' thing happening here? Thanks for listening! Dave172.129.2.5500:15, 29 November 2006 (UTC)[reply]
The vestibular nerves, the nerves that convey auditory information from the ear to the brain, actually split in two with one branch going to the ipsilateral and one to the contralateral side. Thus the only difference between hearing things in one ear as opposed to the other is the timing of the impulse to either side of the pons, where the auditory cortex is. Therefore, unlike most other senses (the sense of balance is the same as with hearing, but vision, smell, touch, and probably taste are conveyed slightly differently to either side of the brain), hearing is essentially sensed the same on both sides. If you feel that your understanding of sounds is better in one ear than the other, you are probably imagining things, unless you have some sort of signal conduction block in the midline of your pons (very unlikely). Either way, it's in your head. --This is not intended as medical advice or a diagnosis. If you feel you have a medical problem, see a physician.-- Tuckerekcut01:00, 29 November 2006 (UTC)[reply]
...it`s in your head." Good one! Perhaps I didn`t 'spell it out' properly: I have no problem understanding the SOUNDS of the words, it`s more like I have difficulty understanding the MEANING. Maybe an exemple will clarify: Suppose I was given a test to repeat a 7-number sequence. Despite hearing every number perfectly well, I would succeed in remembering much better while sounds were isolated to left ear only vs. right ear only. I hope this clears things up. And no, I don`t believe I have any medical problem. Thanks for your responses so far. Dave 172.129.2.5503:40, 29 November 2006 (UTC)[reply]
You may have an undiagnosed problem. The portion of your brain which processes input from one ear may not be working properly. I believe, after certain types of brain damage, people can only recognize objects with one eye. You may have something similar, but with the ears. Have you done testing to establish the difference in memorization, or is it just a casual observation ? StuRat07:07, 29 November 2006 (UTC)[reply]
(Edit conflict !) I suppose that it is natural that one organ of a pair is better than the other? We can't expect both our ears / eyes / kidneys etc to be tuned perfectly. I have noticed that one of my eyes sees colours (very) slightly differently from the other. For example, if I look at something red with each of my eyes, I can make out that the shade of red seen by the right eye is slightly different from the shade seen by the left eye. I have heard this from others too. But the preference may be a matter of taste, or may depend on your handedness. I being right handed, when I need to close an eye, tend to close by left eye though I don't have any problem with the left eye.-- WikiCheng | Talk07:11, 29 November 2006 (UTC)[reply]
I meant to ask if I swallowed one whole then I would feel sick or die? It says that the ricin in one-two castor beans can kill an adult, but does it need to go through any processing or extraction to kill? Because ricin talks all about that. X[Mac Davis] (DESK|How's my driving?) 02:35, 29 November 2006 (UTC)[reply]
Attach a steel cable running through the muscle, anchored well into the bone near each ligament. That should create artificial strength in the weakest muscle. --Kainaw(talk)02:14, 29 November 2006 (UTC)[reply]
I just found the phrase "artificially strengthen" to be funny. I don't consider excercise to be artificial. However, feel free to delete your own questions. --Kainaw(talk)02:40, 29 November 2006 (UTC)[reply]
Also it may be worth adding because it is a common misconception: strengthening your abs does not necessarily help to reduce the fat accumulating on your stomach region, it doesn't work that way. Weight loss and strength training are two different things. Vespine03:05, 29 November 2006 (UTC)[reply]
Depends what you want to fertilise, obviously the lawn cannot take it at that concentration. I don't know if anything would like it, as it removes water from the plant. Next time you pee on the lawn, give it a good water when you get over the hangover :). --liquidGhoul04:16, 29 November 2006 (UTC)[reply]
I have an idea for dealing with weeds; train your pets to pee on them. The urine will kill the weeds. Then, once diluted by rain, it will fertilize the rest of the lawn. StuRat06:56, 29 November 2006 (UTC)[reply]
B12/Cyanocobalamin
What meats often have the highest amounts of B12? Does the B12 found in sports drinks and other artificial products have the same effect as more natural or direct sources of the vitamin? Thank you.
The above SEC filing states that Chris DeWolfe owns 114,825 of InterMix, which is less than 1% of the company. InterMix was bought for $580M in cash (or the equivalent of $12 per share of InterMix shares) by News Corp as specified in this document:
Closer to $1.4 gross. Did he have costs associated with acquiring the shares? If so, you would have to deduct them to get the profit. And don't forget about taxes. -THB04:28, 29 November 2006 (UTC)[reply]
Reverse polarity and antimatter query
Is antimatter made by reversing the polarity of subatomic particles? and I slightly understand the geomagnetic reversal for the earth. But are other particles or objects of polarity reversed often, if yes what is an example?...and can you reverse the polarity of a person if they are charged with static electricity, if yes, what would occur?69.150.209.1306:20, 29 November 2006 (UTC)[reply]
Antimatter is only made in pair production with matter. Mathematically it is equivalent to matter with its charge and parity flipped, or with time reversed, but it cannot be created in this manner. Polarity is a different phenomenon, refering to the alignment of atoms; reversing polarity would result in the electromagnetic field produced by those atoms being reversed. Hopefully that's a start at least. -- SCZenz06:50, 29 November 2006 (UTC)[reply]
repulsive quantum vacuum
This page says they were going to measure it http://www.quantumfields.com/AIAA2001.pdf, this page says that it was measured at 0.5 micronewtons http://arxiv.org/ftp/quant-ph/papers/0511/0511179.pdf, the first report was filed at NASA and the other seems to come from a respected physics institute. So does this mean we have an anti-casimir effect then, a force that can push outwards instead of pull inwards?
Greg
This isn't my area of physics, so I'm not able to read the papers very well or to vouch for their reputability, but... As I read the first paper, it states that they're working on an experiment to see if configurations producing a repulsive force due to the casimir effect exist. (The second paper seems more narrow, and I'm not sure exactly how it relates to your question.) But yes, it would appear that, in theory, some scientists expect that what you describe is possible. -- SCZenz08:15, 29 November 2006 (UTC)[reply]
Photon Duality
An Old subject but could someone please explain the current theory of partical duality. I thought I had it figured out, "Transformes from energy to matter for a brief instant durring an interaction by the equation E=mc^2. Durring the interaction I thought that when it existed as matter is speed was <<C then back to energy propegating through space time at C. Like the particles in a accelerator that result from a smash, these particles exist as mass and in an electromagnetic field spiral and pop into energy. Likewise in space-time particles are continually popping from energy fluxuations to matter, then back to energy. I have a head ach,, any replies??~--Aaron hart09:29, 29 November 2006 (UTC)[reply]
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