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I have stumbled upon some information that DNA is condusive of Electricity and therefore is effected by EMF's. The source claims the effect is either the cause or cure for cancer's and other cellular diseases. Is there any validity to this claim and has there been experiments as to the effects of EMF's on cellular DNA?
The cancer stuff sounds like quackery, but I guess DNA might conduct electricity in a sense. When you hydrate DNA at a reasonable pH, it's strongly negatively charged, so it attracts an atmosphere of positive counter-ions that's much more concentrated than in the rest of the solution. These might be reasonably free to move parallel to the molecule...? Melchoir04:09, 21 July 2006 (UTC)[reply]
While there is some evidence that cells can respond to the presence of electromagnetic fields, the evidence linking EMFs to disease are tenuous and controversial at best. I'll note that it's virtually impossible to prove a negative, but the evidence available to date suggests that EMFs are responsible for very few – if any – illnesses. Your cellular phone is more likely to kill you by distracting you as you cross the street than by giving you brain cancer. TenOfAllTrades(talk) 15:01, 21 July 2006 (UTC)[reply]
Hi - a question for history of science people - can anyone tell me if there were any observations made by scientists on the phenomenon of protective colouration/camouflage before Thayer in the 19th century? If so, could you point me towards any online texts? Thanks in advance Adambrowne66607:27, 21 July 2006 (UTC)[reply]
There was an english naturalist named Henry Walter Bates (we have an uninformative stub on him) who apparently spent some time studying countershading in nature. [this] says Thayer was influenced by his work. He apparently also studied the related phenomenon of a species imitating a well-armed or poisonous species to gain the advantage of their reputation - it's called Bayesian mimicry. It does seem that Thayer was the first person to address the subject of camouflage comprehensively. --Bmk14:45, 21 July 2006 (UTC)[reply]
That's great, Bmk, thanks - but I wonder if there are any even earlier examples of this observation being made, even if they're not entirely in the scientific context - in bestiaries, for example? Adambrowne66622:29, 21 July 2006 (UTC)[reply]
I don't know for sure, but i would be surprised if some of the early pigmentation biologists didn't comment on camouflage. For example, in 1819 Sangiovanni published Descrizione di un particolare sistema di organi cromoforo espansivo-dermoideo e dei fenomeni che esso produce, scoperto nei molluschi cefaloso (G. Enciclopedico Napoli. 1819; 9:1-13) characterising cephalopod chromatophores. It would be odd, considering their mastery of pigmentation control, if there were not some mention of camouflage. I did, at one time, have a reproduction of his paper in Italian (which i can't read), so never bothered reading past what i was specifically interested in.
There is an extensive chapter in The Pigmentary System: Physiology and Pathophysiology[1] on the history of pigmentary science that may address the issue. Rockpocket05:51, 22 July 2006 (UTC)[reply]
why does height stop increasing after a certain age in human beings?i know one reason that is growth harmone production decreases gradually...but why does it decrease?or is there any other reason for the height to stop growing.....--203.109.89.13012:41, 21 July 2006 (UTC)hima[reply]
It has to do with growth hormones and puberty, but a quick browse of the relevant articles doesn't reveal anything specific. If I recall from (you are going to hate me for this) an episode of "Doogie Howser, M.D.", the bones grow during stages of adolescence and eventually are stopped in a process that 'caps them off', additional hormones left in (or introduced to) the system have no effect on their length any more. edit- on second thought what was I thinking??? Just type in Human height and you will learn everything you wanted to know. --Jmeden200021:29, 21 July 2006 (UTC)[reply]
I may have some details wrong but... Bones grow "as cartilage" which eventually matures into bone, upon which growth ceases. One cause of bone maturation is estradiol, which in men is mainly produced by aromatization of testosterone (this is why steroid use in teenagers results in stunted growth). Something like that. Jack Daw10:08, 22 July 2006 (UTC)[reply]
bones have plates called growth plates at their ends... a few years after puberty they literally " burn off" and hence no height increase is seen.it is mostly 18 for girls and 21 for boys..--219.91.134.23814:24, 22 July 2006 (UTC)[reply]
At work, I'm often asked to make birthday cards for people. I print it on plain card stock. It doesn't look professional because it doesn't have a waxed coating like the Hallmark cards do. I can laminate them, but I would rather wax coat them. Does anyone know of a process for wax coating that I can do without the resources that Hallmark has? --Kainaw(talk)14:10, 21 July 2006 (UTC)[reply]
OK, so I'm leaving for Spain in about 2 hours and I was wondering if you could tell me if it would be ok to plug in my ipod to recharge it with my AC Power Supply, which lets me plug my ipod into an American socket.
On the AC Power Supply thingy, it says on the back:
MODEL: 17B061001
INPUT: 100-240V~ 50-60Hz 0.2A
OUTPUT: 5.0V 500mA
FILE NO: E213987
DATE CODE: 1205
I.T.E. POWER SUPPLY
For I.T.E. use only
I've got the little converter thingy to switch it from American to European plug... but it doesn't convert the voltage...
I've already used this in the British Isles w/ my ipod and hair straitener and it worked fine... I just want to be really sure…
~Cathy T.~
I just found this: "Electricity supply is 220 volts throughout Spain with 2 pin wall sockets." Although I already knew that from wikipedia...
~Cathy T.~
This is standardised in the EU, afaik, so whatever worked in the UK should work in Spain. But the link you give shows that the whole of Europe (actually, most of the world) uses 220-240V/50Hz. So that's within the range of the adapter thingy. :) I'm not aware of any other possible issues. DirkvdM15:20, 21 July 2006 (UTC)[reply]
Spain uses 220V / 50Hz power mains, and the plugs are the "Europlug" configuration. See an image of it here: Europlug. Your ipod will work fine with the proper convertor that mates to the Europlug (cool how most manufacturers are making their products ready to use world-wide, huh?)
Thanks for all the help... I thought it would be fine. I just wanted to be really sure... cause those ipods are expensive! It is nice that the world is going more universal. :)
Because it's isotropic? If this is a homework question you should do it yourself. If you know what the bond structure of diamond is, that should tell you. DJ Clayworth17:57, 21 July 2006 (UTC)[reply]
It's because some bond angles, for example between carbon atoms as in diamond, minimize energy. Basically the bonds of an atom organize themselves so they have as large an angle from all other bonds to the same atom as possible, to minimize energy. In the case of diamond, there are four bonds per carbon atom, so they arrange themselves in a tetrahedral shape. When you put all those tetrahedrons together, they naturally form a regular, isotropic structure - the crystal structure. The crystal structure it forms is called face centered cubic. --Bmk18:17, 21 July 2006 (UTC)[reply]
Diamond might be optically isotropic, but its crystal structure isn't isotropic. Like any crystal, it's got preferred directions all over the place. I imagine this distinction is the heart of Masatran's question. Melchoir19:18, 21 July 2006 (UTC)[reply]
I was using isotropic in the sense that it has a crystal structure that is translation invariant. I'm not sure exactly what the question meant. --Bmk19:26, 21 July 2006 (UTC)[reply]
Ah. My understanding is that isotropy means rotational invariance, while homogeneity means translation invariance. Melchoir19:34, 21 July 2006 (UTC)[reply]
Well, very short wavelengths of "light" on the scale of the crystal structure do respond to the anisotropies; that's why X-ray crystallography works. But the comparatively long optical wavelengths only see, in some sense, the first-order effects. In the specific case of diamond, there's too much symmetry, and the permittivity tensor is forced to have a single eigenvalue in all directions, making it a scalar. Melchoir06:25, 22 July 2006 (UTC)[reply]
According to that same table, it looks like a 0.2 carat diamond would cost around $1500 per carat, or $300 in total. That's just a rough estimate. Hyenaste(tell)22:09, 21 July 2006 (UTC)[reply]
I recently heard the statement, without any scientific attribution, that 'recent research' suggests that the body recognizes artificial sweeteners as sugars and reacts with the same responses in terms of excessive insulin production and insulin resistance at the cellular level in Type II diabetics. Does anyone know of any supporting evidence for this statement? --Mlbenson17:45, 21 July 2006 (UTC)[reply]
I've not heard any evidence to supportsuch a statement, and since I know how insulin signaling works, I'm skeptical that there's much to it. Simply, pancreaticbeta cells release insulin in response to increased blood sugar because that sugar is immediately piped into a metabolic channel, resulting in an increased ATP:ADP ratio. This activates potassium channels that depolarize the membrane, activating calcium channels leading to subsequent activation of exocytosis machinery. Fake sugars shouldn't increase blood glucose and would then be unable to induce insulin release via the classical pathway. More here.
Now, there are other mechanisms that can cause insulin release (such as adrenergic signaling), but I've seen no evidence that artificial sweetners have any effects on those systems, either. -- Scientizzle00:47, 28 July 2006 (UTC)[reply]
Because of the genetic material(DNA/RNA) found in a virus, it should' be considered as a lifeform... well, I think so(It's totally MY own opinion). I don't know of any such 'staff, which is both non-living, and having a genetic material at the same time;I will be really grateful IF ANYONE CAN PROVIDE ME SUCH AN EXAMPLE.Pupunwiki12:44, 22 July 2006 (UTC)[reply]
The original question had nothing to do with "life" or "non-life", but was simply asking for the constituent parts of a virus: a nucleic acid (RNA/DNA), a protein capsid, +/- an envelope and any viral enzymes. For those troubled about whether viruses are living or non-living: you'd be better off considering if that's a false dichotomy, and if it's a categorization at all useful when applied to viruses. How is it going to make any difference if you term a virus living? or non-living? What's non-living and contains DNA? A corpse. The dried scrapings from the inner cheek. A preserved surgical specimen. All kinds of things. - Nunh-huh15:51, 22 July 2006 (UTC)[reply]
If viruses were alive, antibiotics would kill them. By definition. Since they don't, they ain't. Surely it can't be more complicated than that, right? Matt Deres23:44, 25 July 2006 (UTC)[reply]
I can't believe you're serious, but in case you are: antibiotics don't kill you, yet you're alive. Go figure. - Nunh-huh00:32, 26 July 2006 (UTC)[reply]
Nah, I just forgot my smiley, but in case you're serious, consider this: if you have a cold and decide to chug a dispensor jug of penicillin or other antibiotic - you'd be dead, but the little rhinoviruses wouldn't be (well, they'd be trapped in your corpse, but you know what I mean). Don't confuse "not harmful at prescribed doses" with "won't kill you". Two smileys to take care of the backorder :-) :-) Matt Deres19:57, 26 July 2006 (UTC)[reply]
According to the small print on a bottle of Lucozade, "this product should not be used to replace fluids lost by diarrhoea". Why should this be, especially given that it is meant to help convalescence? smurrayinchester(User), (Talk)19:34, 21 July 2006 (UTC)[reply]
I am designing a capacitor plate to measure small variation in capacitance, for a pressure transducer. My base plate is of ceramic type and in have to coat some metal as electrode. My desire capacitance range is 10pF to 50pF with small variation of .001pF. I am using vacuum as dielectric between ceramic plate and deflection membrane (INCONEL).
Kindly provide my information’s regarding to designing parameters, material to be coated, and different shape in which material can be coated on ceramic plate. I shall be very thankful for these kind information’s.
Abawan
Email address removed
See Capacitor. All you need is the equation , where C is the capacitance, ε is the permittivity of the dielectric (in your case, ε0, the permittivity of free space), A is the area of the plates and d is the spacing between them. As for the coating material, I'll leave that question to a chemist, but the choice of material will have no effect on the capacitance. --Heron09:26, 22 July 2006 (UTC)[reply]
I found patches of these plant on a hike in southern Michigan on the 4th of July weekend. I have no idea what it is. I thought it was a fungus but, on touching it, it didn't feel soft like fungus but oily and hard like a nutmeat. Anyone know what it is? Rmhermen20:03, 21 July 2006 (UTC)[reply]
I was once taught that as cement,aggregate and water mixed, a chemical reaction occurs that forms molecules of concrete. These molecules have microscopic sized quills protruding like quills on a Porqupine egg. These quills interlace with surrounding molecules,thus locking them together. This interlocucution gives concrete it's strength. Furthermore,on a decreasing scale,these molecules continue to form for a very long time, and that is why very old concrete is so very hard. Is this true? I have read the Wikapedia article on concrete and it does not answer this question.
There isn't a "concrete molecule" as such, concrete is hydrated mineral. When it cures, it forms bonds with water molcules - that might be the 'spines' you're referring to. Concrete does continue curing for years, although it would be unlikely to contribute much additional strength. Peter Grey19:45, 22 July 2006 (UTC)[reply]
Is it true that mars will be so close to us next month that we will be able to clearly see it as large as a full moon?21:21, 21 July 2006 (UTC)(hobgoblin)
As you can see in this File:Inner Planets Image.PNGThe current state of the planets, viewed from above the ecliptic, generated in Celestia picture of the current state of solar system (made using the excellent freeware celestia), Mars and Earth are nowhere near at their closest point. In fact, viewed from this position, the planets are orbiting counterclockwise, so they are currently getting farther apart. Essentially, Earth will have to "lap" mars around the sun before the two planets align at their closest approach of 0.5 AU, or around 75 million km. The angular diameter of astronomical bodies is quite easy to calculate. Basically, you form a right triangle with three points: Your eye, the center of the planet, and a point on the circumference of the planet. Find the actual radius of the planet, figure out how far away the planet is, divide, take the arctangent, multiply by two, and you have the angular width of the planet. Too lazy to do it myself :) --Bmk00:24, 22 July 2006 (UTC)[reply]
Mars and Earth reached their closest distance last year, actually, around November 2005. Mars' apparent diameter from earth was 20.1" (according to the excellent program Celestia—no need to calculate arctangents); Jupiter's apparent diameter was still larger (around 32"). The Moon's apparent dimater was 32' (that's minutes, not seconds; perhaps that's where the confusion arose?). — Knowledge Seekerদ03:26, 22 July 2006 (UTC)[reply]
This article is currently running through AfD as being a possible hoax. I was curious if the knowledgeable people here could help with just knowing if this does in fact exist. Yanksox22:07, 21 July 2006 (UTC)[reply]
I really need to know if the rear passenger side windows in a 1965 and 1967 chevrolet bel air station wagon are the same? I don't have much money so I don't want to spend any money buying the wrong window for my car. Thanks. --72.20.69.1223:34, 21 July 2006 (UTC)[reply]
