:''Note: Ultraviolet (TV miniseries) is also the name of a 1998 United Kingdom television miniseries about vampires.'' ---- Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-ray. It can be subdivided into near UV (380–200 nanometre wavelength) and extreme or vacuum UV (200–10 nm). When considering the effects of UV radiation on human health and the environment, the range of UV wavelengths is often subdivided into UVA (380–315 nm), also called Long Wave or "blacklight"; UVB (315–280 nm), also called Medium Wave; and UVC (280-10 nm), also called Short Wave or "germicidal". See 1 E-7 m for a list of objects of comparable sizes. The name means "beyond violet" (from Latin ''ultra'', "beyond"), violet (color) being the color of the shortest wavelengths of visible light. Some of the UV wavelengths are colloquially called black light, as it is invisible to the human eye. Some animals, including birds, reptiles, and insects such as bees, can see into the near ultraviolet. Many fruits, flowers, and seeds stand out more strongly from the background in ultraviolet wavelengths as compared to human color vision. Many birds have patterns in their plumage that are invisible at usual wavelengths but seen in ultraviolet, and the urine of some animals is much easier to spot with ultraviolet. [[Image:SOHO_EIT_ultraviolet_corona_image.gif|thumb|right|256px|The sun corona as seen in "deep" ultraviolet light at 17.1 nanometer by the Extreme ultraviolet Imaging Telescope instrument aboard the Solar and Heliospheric Observatory spacecraft]] The Sun emits ultraviolet radiation in the UVA, UVB, and UVC bands, but because of absorption in the Earth's atmosphere's ozone layer, 99% of the ultraviolet radiation that reaches the Earth's surface is UVA. (Some of the UVC light is responsible for the generation of the ozone.) Ordinary glass is transparent to UVA but is opaque to shorter wavelengths. fused quartz, depending on quality, can be transparent even to vacuum UV wavelengths. The onset of vacuum UV, 200 nm, is defined by the fact that ordinary air is opaque below this wavelength. This opacity is due to the strong absorption of light of these wavelengths by oxygen in the air. Pure nitrogen (less than about 10 ppm oxygen) is transparent to wavelengths in the range of about 150–200 nm. This has wide practical significance now that semiconductor manufacturing processes are using wavelengths shorter than 200 nm. By working in oxygen-free gas, the equipment does not have to be built to withstand the pressure differences required to work in a vacuum. Some other scientific instruments, such as circular dichroism spectrometers, are also commonly nitrogen purged and operate in this spectral region. == Discovery == Soon after infrared radiation had been discovered, the German physicist Johann Wilhelm Ritter began to look for radiation at the opposite end of the spectrum, at the short wavelengths beyond violet. In 1801 he used silver chloride, a light-sensitive chemical, to show that there was a type of invisible light beyond violet, which he called chemical rays. At that time, many scientists, including Ritter, concluded that light was composed of three separate components: an oxidising or calorific component (infrared), an illuminating component (visible light), and a reducing or hydrogenating component (ultraviolet). The unity of the different parts of the spectrum was not understood until about 1842, with the work of Macedonio Melloni, Alexandre-Edmond Becquerel and others. During that time, UV radiation was also called "actinic radiation". == Health effects == [[Image:DNA UV mutation.gif|thumb|right|350px|Ultraviolet photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent bases bond with each other, instead of across the "ladder". This makes a bulge, and the distorted DNA molecule does not function properly.]] In general, UVA is the least harmful, but can contribute to the aging of skin, DNA damage and possibly skin cancer. It penetrates deeply and does not cause sunburn. Because it does not cause reddening of the skin (erythema) it cannot be measured in the SPF testing. There is no good clinical measurement of the blocking of UVA radiation, but it is important that sunscreen block both UVA and UVB. High intensities of UVB light are hazardous to the eyes, and exposure can cause ''welder's flash'' (photokeratitis or arc eye). UVA, UVB and UVC all can damage collagen fibers and thereby accelerate aging of the skin. halogen lamp have bulbs made of quartz, not of ordinary glass. Tungsten-halogen lamps that are not filtered by an additional layer of ordinary glass are a common, useful, and possibly dangerous, source of UVB light. UVA light is known as "dark-light" and, because of its longer wavelength, can penetrate most windows. It also penetrates deeper into the skin than UVB light and is thought to be a prime cause of wrinkles. UVB light in particular has been linked to skin cancers such as melanoma. The radiation ionizes DNA molecules in skin cells, causing covalent bonds to form between adjacent thymine bases, producing thymidine dimers. Thymidine dimers do not base pair normally, which can cause distortion of the DNA helix, stalled replication, gaps, and misincorporation. These can lead to mutations, which can result in cancerous growths. The mutagenicity of UV radiation can be easily observed in bacterium cultures. This cancer connection is the reason for concern about ozone depletion and the ozone hole. UVC rays are the strongest, most dangerous type of ultraviolet light. Little attention has been given to UVC rays in the past since they are normally filtered out by the ozone layer and do not reach the Earth. Thinning of the ozone layer and holes in the ozone layer are causing increased concern about the potential for UVC light exposure, however. A positive effect of UV light is that it induces the production of vitamin D in the skin. Grant (2002) claims tens of thousands of premature deaths occur in the US annually from cancer due to insufficient UVB exposures (apparently via vitamin D deficiency). Another effect of vitamin D deficiency is osteomalacia, which can result in bone pain, difficulty in weight bearing and sometimes fractures. Ultraviolet radiation has other medical applications, in the treatment of skin conditions such as psoriasis. UVB and UVA radiation can be used, in conjunction with psoralens (PUVA treatment). ===Protection=== As a defense against UV radiation, the body tans when exposed to moderate (depending on human skin color) levels of radiation by releasing the brown pigment melanin. This helps to block UV penetration and prevent damage to the vulnerable skin tissues deeper down. Suntan lotion that partly blocks UV is widely available (often referred to as "sun block" or "sunscreen"). Most of these products contain an "SPF rating" that describes the amount of protection given. This protection applies only to UVB light. In any case, most dermatologists recommend against prolonged sunbathing. It is advisable to use protective eyewear when working with ultraviolet radiation, especially short wave ultraviolet. Ordinary eyeglasses give some protection. Most plastic lenses give more protection than glass lenses. Some plastic lens materials, such as polycarbonate, block most UV. There are protective treatments available for eyeglass lenses that need it to give better protection. The most important reason that ordinary eyeglasses only give limited protection, however, is that light can reach the eye without going through the lens. Full coverage is important if the risk from exposure is high. Full coverage eye protection is usually recommended for high altitude mountaineering, for instance. Mountaineers are exposed to higher than ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice. == Uses == UV light has many various uses. Some of them are as follows: ===Black lights=== A black light is the name commonly given to a lamp emitting almost entirely long wave UV radiation and very little visible light. Ultraviolet radiation itself is invisible, but illuminating certain materials with UV radiation prompts the visible effects of fluorescence and phosphorescence. Black light testing is commonly used to authenticate antiques and bank notes. It is extensively used in non-destructive testing (NDT); fluorescing fluids are applied to metal structures and illuminated with a black light. Cracks and other artefacts can easily be detected. Black lights are used in forensic examination and testing, as naturally fluorescing remnants can be seen. It is also used to illuminate pictures painted with fluorescent colors (preferably on Black Velvet to intensify the illusion of self-illumination). The fluorescence it prompts from certain textile fibers is also used as a recreational effect (as seen for instance in the opening credits of the James Bond film A View to a Kill). ===Fluorescent lamps=== Fluorescent lamps produce UV radiation by the emission of low-pressure mercury (element) gas. A phosphorescent coating on the inside of the tubes absorbs the UV and becomes visible. The main mercury emission wavelength is in the UVC range. Unshielded exposure of the skin or eyes to mercury arc lamps that do not have a conversion phosphor is quite dangerous. The light from a mercury lamp is predominantly at discrete wavelengths. Other practical UV sources with more continuous emission spectra include Xenon flash lamps (commonly used as sunlight simulators), deuterium arc lamps, mercury-xenon arc lamps, metal-halide arc lamps, and tungsten-halogen incandescent lamps. ===Pest control=== Ultraviolet fly traps are used for the elimination of various small flying insects. They are attracted to the UV light and are killed using an electrical shock or trapped once they come into contact with the device. ===Spectrophotometry=== UV/VIS spectroscopy is widely used as a technique in chemistry, for analysis of chemical structure, most notably conjugated systems. UV radiation is often used in visible spectrophotometry to determine the existence of fluorescence a given sample. ===Astronomy=== In astronomy, very hot objects preferentially emit UV radiation (see Wien's law). However, the same ozone layer that protects us causes difficulties for astronomers observing from the Earth, so most UV observations are made from space. (see UV astronomy, space observatory) ===Analyzing minerals=== Ultraviolet lamps are also used in analyzing minerals, gemstone, and in other detective work including authentication of various collectibles. Materials may look the same under visible light, but fluorescence to different degrees under ultraviolet light; or may fluoresce differently under short wave ultraviolet versus long wave ultraviolet. UV fluorescent dyes are used in many applications (for example, biochemistry and forensics). The fluorescent protein Green Fluorescent Protein (GFP) is often used in genetics as a marker. Many substances, proteins for instance, have significant light absorption bands in the ultraviolet that are of use and interest in biochemistry and related fields. UV-capable spectrophotometers are common in such laboratories. ===Photolithography=== Ultraviolet radiation is used for very fine resolution photolithography, a procedure where a chemical known as a photoresist is exposed to UV radiation which has passed through a mask. The light allows chemical reactions to take place in the photoresist, and after development (a step that either removes the exposed or unexposed photoresist), a geometric pattern which is determined by the mask remains on the sample. Further steps may then be taken to "etch" away parts of the sample with no photoresist remaining. UV radiation is used extensively in the electronics industry because photolithography is used in the manufacture of semiconductors, integrated circuit components and printed circuit boards. ===Checking electrical insulation=== A new application of UV is to detect corona discharge (often simply called "corona") on electrical apparatus. Degradation of insulation of electrical apparatus or pollution causes corona, wherein a strong electric field ionizes the air and excites nitrogen molecules, causing the emission of ultraviolet radiation. The corona degrades the insulation level of the apparatus. Corona produces ozone and to a lesser extent nitrogen oxide which may subsequently react with water in the air to form nitrous acid and nitric acid vapour in the surrounding air. [http://www.seeing-corona.com/] ===Sterilization=== Ultraviolet lamps are used to sterility workspaces and tools used in biology laboratories and medical facilities. Conveniently, low pressure mercury discharge lamps emit about 50% of their light at the 253.7 nm mercury emission line which coincides very well with the peak of the germicidal effectiveness curve at 265 nm. UV light at this wavelength causes adjacent thymine molecules on DNA to dimerize, if enough of these defects accumulate on a microorganism's DNA its replication is inhibited, thereby rendering it harmless. Since microorganisms can be shielded from ultraviolet light in small cracks and other shaded areas, however, these lamps are used only as a supplement to other sterilization techniques. ===Disinfecting drinking water=== Ultraviolet radiation is increasingly being used to disinfect drinking water and in waste water treatment plants. Recently it was discovered that ultraviolet radiation could treat Cryptosporidium, previously unknown. The findings resulted in two [http://www.calgoncarbon.com/company/news/index.cfm?mode=detail&id=DF8B2807-AB22-705E-D9769AEA0B6A744E US patents] and the use of UV radiation as a viable method to treat drinking water. === Food Processing === As consumer demand for fresh and "fresh like" food products increases, the demand for a nonthermal method of food processing is likewise on the rise. In addition, public awareness regarding the dangers of food poisoning is also raising demand for improved food processing methods. Ultraviolet radiation is used in several food processes to remove unwanted microorganisms. UV light can be used to pasteurization fruit juices by pumping the juice over a high intensity ultraviolet light source. The effectiveness of such a process depends on the UV absorbance of the juice. ===Fire detection=== Ultraviolet (UV) detectors generally use either a solid-state device, such as one based on silicon carbide or aluminum nitride, or a gas-filled tube as the sensing element. UV detectors which are sensitive to UV light in any part of the spectrum respond to irradiation by sunlight and artificial light. A burning hydrogen flame, for instance, radiates strongly in the 185 to 260 nanometre) range and only very weakly in the IR region, while a coal fire emits very weakly in the UV band yet very strongly at IR wavelengths; thus a fire detector which operates using both UV and IR detectors is more reliable than one with a UV detector alone. Virtually all fires emit some radiation in the UVB band, while the Sun's radiation at this band is absorbed by the Earth's atmosphere. The result is that the UV detector is "solar blind", meaning it will not cause an alarm in response to radiation from the Sun, so it can easily be used both indoors and outdoors. UV detectors are sensitive to most fires, including hydrocarbons, metals, sulfur, hydrogen, hydrazine, and ammonia. Arc welding, electrical arcs, lightning, X-rays used in nondestructive metal testing equipment (though this is highly unlikely), and radioactive materials can produce levels that will activate a UV detection system. The presence of UV-absorbing gases and vapors will attenuate the UV radiation from a fire, adversely affecting the ability of the detector to "see" a flame. Likewise, the presence of an oil mist in the air or an oil film on the detector window will have the same effect. ===Curing of adhesives and coatings=== Certain adhesives and coatings are formulated with photoinitiators. When exposed to the correct wavelengths of UV light, polymerisation occurs, and so the adhesives harden or cure. Usually, this reaction is very quick, a matter of a few seconds. Applications include glass and plastic bonding, and the coating of flooring. ==See also== * UV index ==References== * Grant, William B. (2002). [http://www3.interscience.wiley.com/cgi-bin/abstract/91016211/ABSTRACT An estimate of premature cancer mortality in the US due to inadequate doses of solar ultraviolet-B radiation.] ''Cancer'' 94 (6), 1867–1875. * Matsumura Y, Ananthaswamy HN (2004). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15020192 Toxic effects of UV radiation on the skin.] ''Toxicol. Appl. Pharmacol.'' 195 (3), 298-308. * Hu S, ''et al.'' (2004). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15262692 UV radiation and melanoma in US Hispanics & blacks.] ''Arch Dermatol.'' 140 (7), 819-824. Electromagnetic spectrum
What is the source of this claim? *Ultraviolet light is the cause of [skin cancers]? such as melanoma?. The radiation ionises DNA molecules in skin cells, causing mutations which can result in cancerous growths. I am going to label it an "environmentalist fear" if I can't find any science to back it up. (I'll look myself; I won't be hasty.) -- User:Ed Poor Ed -- what IS it with you? My goodness. It seems that every time you see something you don't agree with, you pigeonhole it into "beliefs of Liberals" "beliefs of environmentalists" -- as if those are by definition Bad Things. I can't quote any particular scientist, but I'm pretty sure that the AMA and the Dermatology and Oncology boards would agree to a link between UV rays and melanoma. Why do I think this? Because every time I go to the doctor, and especially to the dermatologist, I see pamphlets and posters warning me about not wearing sun block and staying out of the sun when UVA and UVB rays are most intense, in order to minimize the risk of skin cancer. Why don't you just change the bloody thing to "has been linked to skin cancer", rather than pulling your usual namecalling act? user:JHK :Are you calling me a "namecaller"? User:Ed Poor I agree. I'm hardly an environmentalist myself, and would probably apall a greenpeacer if I got into a discussion with them, but I have with my own two hands conducted experiments in which I used UV light to induce mutations in bacteria. To say that it's some sort of environmentalist fearmongering is inane. user:Bryan Derksen :(I should mention, though, that it may be reasonable to bring up issues about the ''magnitude'' of the risk caused by UV exposure. That's something which is indeed sometimes blown all out of proportion. But please, find some actual numbers before doing that.) user:Bryan Derksen Bryan, please add something about bacteria mutations, at least one sentence! :Alright, but I'll have to dig out some very old notes first. It's something I did back in an undergrad genetics lab. :) user:Bryan Derksen Also, I am not disputing the contention that UV can cause cancer. I am only asking for sources. I want to distinguish between: #scientific sources that have proved something (or at least found it to be highly likely), and #claims by advocacy groups. For instance, does UV cause melanoma or non-melanome cancers? How much UV exposure will cause cancer? Is there a threshold over which most people will get a cancer? Or have studies (cite them, please) found an increased rate of cancer at various exposure levels? E.g., double the UV, and the annual cancer rate increases from 100 per million to 180 per million. Please don't misunderstand. I don't want to suppress science! I only want to label advocacy and distinguish it from science. User:Ed Poor ---- You're demanding a lot of tedious legwork documenting scientific consensus. Or would you accept "Karen Landau, M.D. (personal communication)" as a source? You say you don't dispute the statement--and then want people to run around proving it anyway. If you're questioning a scientific consensus, the onus is on you to provide citations: studies that (for example) compared different levels of UV exposure and found no increase in cancer. user:Vicki Rosenzweig ---- I did some legwork (just before reading the above). I found a report by WMO, UNEP, NOAA and NASA which said that: *When high-quality measurements have been made in other areas far from major cities and their associated air pollution, decreases in ozone have regularly been accompanied by increases in UV-B. [http://www.al.noaa.gov/WWWHD/Pubdocs/Assessment98/faq8.html] However, they did not give any source for this data. They just show a pretty graph. Given the amount of advocacy over this issue, I hesitate to call this "scientific" The report concedes that: *From 1979 to 1997, the observed losses in the amount of ozone overhead have totaled about 5-6% for northern midlatitudes in winter and spring, about 3% for northern midlatitudes in summer and fall, and about 5% year round for southern midlatitudes. [http://www.al.noaa.gov/WWWHD/Pubdocs/Assessment98/faq10.html] Based on my visual estimate of the slope of their graph [], I estimate that this would cause an increase of 1% to 2% in surface UV radiation. This is less than the increase you would get by driving 30 miles closer to the equator. This pales in comparison with flying from Maine to Florida for your summer vacation. User:Ed Poor :Ed -- you're working out of context -- again. The quote you claim to object to says UV causes melanoma. Your "evidence" relatesz to the hole in the ozone layer and the increase in UVB rays -- not at all the same thing. Please try to stopy going into articles band making objections based on your ''a priori'' beliefs. Articles aren't research projects. Things that are generally accepted, such as the fact that spending lots of time in the sun without protection increases the risk (and some say causes) melanoma, are perfectly acceptable. And if you're going to do legwork, as you call it, please make sure it's relevant. user:JHK ---- My comment to Vicky might be on the wrong talk page (elsewhere I said that there is overlap between CFC, ozone, and UV pages). The question I am interested in is whether CFC emissions are a significant cause of cancer. This has a bearing on whether the Montreal Protocol is good or bad, something the wikipedia will not take sides on; but which its readers will want to decide based on information the wikipedia provides. Are you aware of any scientific evidence supporting the hypothesis that CFC emissions cause ozone depletion, leading to increased surface UV radiation and increased incidence of cancer? If so, please point me to it. I would love to put this info in the wikipedia! User:Ed Poor :That's not the point, Ed. That isn't what you mentioned above, and is part of another article. This is just another of your tedious attempts to create debate -- and not the scholarly kind. As I understand wikipedia policy, this is neither a place for original research, nor for the bulletin-type fora you seem to prefer. If anybody had the time to do the research, I'm fairly sure that he could find scientific articles in peer-reviewed journals that support both positions. The fact that the US and other countries all agreed to lower CFC emissions indicates that there is at least some reason to accept that there are links. Please stop threatening to destroy other people's work "unless they can provide proof." This is just a slightly veiled attempt on your part to present the world according to Ed. That is hardly collegial, and certainly a perversion of the Wiki-way. user:JHK When there are scientific articles in peer-reviewed journals that support both positions an an issue, why not point these out? I think this is the best thing to do when writing an encyclopedia article about scientific questions which researchers have not settled yet. We should distinguish between (A) advocacy based on fear and (B) the findings of science. For example, some people advocate mandatory HIV testing, reporting positive results to public health authorities and quarantine -- based on the fear that AIDS will spread unchecked otherwise. The reason for their advocacy is their fear of an AIDS epidemic. On the other hand, there is the question of what causes AIDS and how its method of contagion. These are scientific questions, which can and should be considered separately. Based on the science, as well as other considerations, advocates make public policy recommendations. Before we debate further, would you please tell me what parts of the above you agree with, Dr. K? User:Ed Poor :Well there's an unclear question. I'm not sure which part of the "above" I should be looking at. Ed, I'm not here to enter into your debating society. I've already come to the conclusion that discussion with you is fairly meaningless, because I have yet to see one contribution you have made that is from the beginning NPOV and because, whether or not you admit it, every initial stub you post is based on what you call "advocacy" -- although in your book things seem to be either "as Ed sees them (the right way)" and "advocates (liberal, loony left, environmentalist...i.e. wrong according to Ed)." I have yet to see you begin with an empirical approach. :Moreover, I find it interesting that, when it's science vs. religion, science is wrong in your book (see evolution, etc.), but when you are trying to limit the expression of a consensus viewpoint that you deem "liberal", "environmentalist", "feminist" or whatever "lesser" advocacy, you scream, "show me the scientific proof!" In my religion, hypocrisy is a kind of sin...I guess that the UC doesn't see it that way. :I also find it interesting that you are always so sure that you are right. I ''am'' actually an expert in my fields, and know a whole lot more than the average person in several other fields, mostly because I have the opportunity to discuss things (in modern history, art history, literature, etc.) with people who are experts. Despite the fact that I know my stuff, I usually check and make sure that new articles I produce and edits I make are correct, because I know I am fallible. But then, I live in a world where we have the obligation to prove ourselves right (sometimes despite other opinions), not in the Ed world, where others have an obligation to prove, not only that Ed's views are right or wrong, but that other legitimate views even exist. I don't actually care enough about this stuff to research it. I care about maintaining a high standard of article and using an appropriate scholarly approach. I only involve myself in this nonsense because your approach to contibutions belittles, and often negates, all the intellectual values (like objectivity and honesty) I have held dear for all of my academic life. user:JHK I am usually right: it's my outstanding characteristic. One of the things I'm right about is the need for sources to back up claims; that's what distinguishes science from mere advocacy. Scientists feel an obligation to explain their findings, even to share their data. They welcome attempts by other to duplicate their results. Only the dishonest or incompetent ones bristle at the suggestion they may have erred. Getting back to the article, I'd like to see just a little bit more of the science of UV and cancer: how much UV, what sort of cancer. I personally consider UV dangerous and would never consider lying on a beach all day sunbathing. However, if I lived in Florida I wouldn't move to Alaska just to reduce my UV exposure by 90%. I'll be happy with the UV-cancer connection when the article provides statistics relating UV levels and the annual number of skin cancer cases. What's so hard about that? User:Ed Poor ---- The astronomy paragraph refers to the shielding by the ozone layer, which has not been introduced. Therefore the current order of the paragraph doesn't make sense and I changed it, Ed changed it back, and I change it again. Ed, give a reason for your preferred order of paragraphs. user:AxelBoldt Your order is better. I am going to move the CFC-ozone-UV-cancer hypothesis out of the article completely, anyway, and put it where it belongs. But not today. I have to consolidate all the info first (a lot of leg work). User:Ed Poor :The UV-cancer connection most certainly belongs into this article and should stay here. user:AxelBoldt ---- ---- Ed, I did a search on the internet for a site that might help clarify some of the health hazards that ultraviolet radiation can cause. I'm not sure if you've seen this site and discounted the results so far or not, but if you haven't, you might find it of interest. http://www.ciesin.org/TG/HH/ozhlthhm.html The problem with science and the public has always been that results that show connections such as you're searching for tends to be published in journals the public rarely reads, and when it does make its way out into the public, non-scientists are the ones doing the interpreting, and of course reading it with their biases. You asked for a connection between CFCs and skin cancer. What you need to actually do is find that CFCs cause depletion in the Ozone layer, which then causes more UV radiation, which causes cancer. I've given one link, after about 3 minutes of checking, maybe I'll look for others at a later date. Another 'interesting' (to me far more apalling than skin cancer in humans) statement I've seen made, and I think is believed by many Marine Biology folks, is that all coral reefs in the world will be gone in 50 years due to increased UV levels. This while arguments continue as to whether scientists have proof or just correlations at the moment. For another case which makes me believe that caution over convenience when science shows a possible correlation, should be the order of the day is the ''Pfisteria'' outbreaks that occurred in NC. I won't go into huge detail, but you might find it interesting Ed... In NC and MD, ''Pfisteria'' outbreaks both occurred around the same time. In MD, it only took a few hundred fish killed with open sores and a handful of fishermen coming down with neurological symptoms for the state government to jump in on a water cleansing program _while_ the science was still going on. In NC, it took millions of dead fish over a few years, and hundreds of people with neurological symptoms (some to the extent where brilliant scientists could no longer count, and people couldn't remember what they were beginning to say at the start of their sentences) before the government even admitted there might be a problem. I realize it's not the goal of the Wikipedia to put forth ideas in order to change the way society handles CFCs or other potentially harmful items, but the thought of no more coral reefs in 50 or so year makes me much less sympathetic to those who have the attitude of "science jumps the gun, all they have is theories not proofs, let's wait and see further evidence first." user:Rgamble ---- Ed, take a look at this link. It's within the same page that I mentioned above. You said you wanted a scientific paper that discussed the matter. Here you go: http://www.ciesin.org/docs/001-503/001-503.html There's another article or two that aren't online, but have their references listed, so you can go check them out. user:Rgamble ---- Scientific American has a good article for the layperson at, http://www.sciam.com/0996issue/0796leffell.html to which I refer interested parties. I also have some observations on the above debate which I believe belong in user talk:Ed Poor and so am putting them there. ---- Anyway ... The article is presently, to my mind, unclear: :The major component of the sun's light is UV-B, but because of absorption in the atmosphere's ozone layer, 99% of the ultraviolet light that reaches the Earth's surface is UV-A. The peak of the sun's energy is in middle of the visible spectrum (I even did a Wien's law calculation to check). It may be that the majority of the sun's ''ultraviolet'' emission is in UV-B (though looking at the blackbody curve I have my doubts about that as well), but the wording "major component of the sun's light" suggests that the majority of the sun's total EM emission is in the UV-B band, which I'm almost certain isn't correct. I haven't changed the article because my brain's melting at the moment and I'm not sure I haven't missed something, but I just wanted to flag it up.User:Bth :I think you're right, that paragraph is incorrect. In fact, it's wrong two ways: Not only is the peak solar emission in the visible (~580 nm), but also there's much more UV-A than UV-B, and it's mostly '''UV-B'' that gets absorbed by the atmosphere (see [http://www.phys.ksu.edu/gene/e1f2.html]). :Definitely needs changing. User:DrBob ::Done.--User:Bth ---- Why is this at ultraviolet instead of ultraviolet radiation? I would think if somebody wanted to shorten the name, they would just use UV. User:Pizza Puzzle ---- I made a change to this article yesterday, before I knew about this talk page. (I'm pretty new to Wikipedia.) Having now read this discussion, I'm wondering why some of the references discussed here aren't mentioned in the article. Is my lonely reference inappropriate? I certainly don't want to give the impression that UV radiation has only positive effects on human health! If it's OK, what's the right way to do internal footnotes (i.e. a little label '[n]' that links to the References section of the article)? I was trying to follow the Proposed Citation Style in wikipedia:Cite your sources, but maybe that's not the right format. Thanks, User:Mignon 18:47, 31 Dec 2003 (UTC) == Ultraviolet as a color == Do you know of any way to modify our eyes so that ultraviolet is visible to us as a color?? This should be known by 2100. :Sure -- use an instrument that translates UV into colors we can see, perhaps in the form of goggles if you want something wearable. Modifying eyeballs themselves to be UV-sensitive isn't impossible theoretically, but it's a huge can of worms since it would require changing our brains as well to make sense of the information. It seems likely to me that if we ever acquire the technology to do that, mere ultravision would be one of the least of the useful applications. (By the way, why 2100 in particular? And why ultravision, for that matter? I'm genuinely curious about your interest.) ::I doubt you'd need to change your brain to make sense of the information. I would think the easiest method to accomplish this would be to simply genetically modify the DNA which codes for the manufacture of the rhodopsin molecules in the retina's cone cells to be a slightly different shape so they are sensitive to UV light. Say for example you do this to the blue light detecting cones in the eye, the brain would simply process UV light then as "blue", to be sure, you'd see a much different world as percieved colors would be all wrong, but it would work I think.--User:Deglr6328 23:24, 12 Aug 2004 (UTC) :::Blue cones are already somewhat sensitive to UV light (at near-visible wavelengths anyway; see cone cell) but the lens and cornea absorb too much below 380 nm for this to be useful. There's a story I've heard of a chemist who had eye surgery which resulted in a much thinner cornea than usual, and afterwards he was able to align UV spectrometers visually, so maybe there are people around with "ultravision" already. -- User:DrBob 23:36, 12 Aug 2004 (UTC) ::::Hmmm, interesting thoughts. :o) Incidentally, I have also heard of the early discoverers/tinkerers of X-rays claiming that when they placed a closed eye in front of an X-ray tube they were able to percieve a faint blue/purple glow, directly seeing the X-rays. I have to say that I don't find this altogether implausable, and I've contemplated adding it to the X-rays article but I can't find where I originally read it and I need to know if it was reputable or not.--User:Deglr6328 19:53, 14 Aug 2004 (UTC) == Does UV exposure cause Melanoma? == The notion that UV exposure causes "skin cancer" seems well supported by the fact that we see basal and squamous cell skin cancers in areas where there is the chronic skin damage, especially sun-related damage. There is not good evidence at all that UV exposure causes melanoma, though, which is the most deadly of the skin cancers, although there is a widespread acceptance among the medical profession that it does. This is really an unupported belief, and the only evidence is epidemiologic: melanoma is more common near the equator. However melanoma is not very related to sun-exposed areas of skin, and one has to propose that sun exposure somehow alters the immune system to create cancers distal to the area of the body exposed to sun. This is sort of a hypothesis to support a hypothesis, and not very convincing. Nevertheless, the UV-Melanoma dogma is deeply ingrained, and is not likely to go away soon just because there is no evidence to support it. If any of your medical buddies insists that UV exposure causes melanoma, ask them whether or not these lethal skin cancers are most commonly found in the most sun-exposed areas of the body. If they don't have a cogent reply they are probably just parroting what they have been taught. ==disputed== "A black light is a lamp emitting only UV light and no visible light." :If that's true, then there are no black lights. Or are cameras just picking up on UV and converting it to fuschia and violet? User:Lysdexia 03:43, 22 Nov 2004 (UTC) *Changed this. Better now.--User:Deglr6328 06:41, 22 Nov 2004 (UTC) "A UV flame radiates in the 185 to 245 nanometre (1850 to 2450 angstrom) range." :What's the context? UV is wider than that. Where are these UV flames? User:Lysdexia 03:55, 22 Nov 2004 (UTC) == UV and Sunburn == In the paragraph, Health effects, of ultraviolet article, it mentions "In general, UVA is the least harmful, but can contribute to the aging of skin, DNA damage and possibly skin cancer. It penetrates deeply and does not cause sunburn.". But in the sunscreen article, it mentions "The best sunscreens block both UV-A and UV-B rays, both of which can cause sunburn.". Would anyone be kind to tell me which one is true? :The first is true, if you define ''sunburn'' as visible damage. I fixed the second article. --User:Heron 08:43, 4 Jun 2005 (UTC) == Ultrapink light == I recently took a picture of my black light with my digital camera. Normaly, when you look at my light, it is purple, but in my digital camera's photo, it was pink. Also, on a side note, in the photo, I was wearing a white shirt which made it glow. It glowed the same blue in both my eyes and the photo, yet the black light was pink. Why? :The colored filters used in the Bayer mask of the digicam's ccd do not have the same optical properties as do the rhodopsin molecules in your eye. The CCD is somewhat sensitive to UV and the colored filters of the mask in front of it behave nonintuitively outside the visible spectrum. In this case the red filter was obviously more transparent to the UV than the green and blue filter materials thus making the camera "think" there's more red light coming from the black light and giving it a pink hue. The reason your shirt is the same color in the photo and to your eye is simple. The cotton in your shirt was fluorescent, it was only emitting blue light, not UV, and therefore the camera has no trouble correctly rendering it. If you have an electric stove, turn it on and let the coil heat up, then turn it off and switch the room lights off. Wait till the coil is no longer glowing very brightly and take a picture(no flash!), if your camera lacks a proper infrared filter you will see a neat effect. --User:Deglr6328 01:26, 3 Jun 2005 (UTC) :: What a nice reply! Maybe the anonymous poster of the question could attach the picture? I'm curious to see it. User:Common Man 05:51, 3 Jun 2005 (UTC) :Thanks for the answer. I'll paste a picture tomorrow. 6/3/05 :Sorry, but I can't figure out how to edit the page correctly, so I will just give you the html to the image. http://en.wikipedia.org/wiki/Image:DSCN1187.JPG
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Words begining with Ultraviolet:
Ultraviolet
Ultraviolet
Ultraviolet-Visible_spectroscopy
Ultraviolet-visible_spectroscopy
Ultraviolet_(series)
Ultraviolet_(TV_miniseries)
Ultraviolet_(TV_miniseries)
Ultraviolet_Astronomy
Ultraviolet_catastrophe
Ultraviolet_catastrophe
Ultraviolet_cutoff
Ultraviolet_divergence
Ultraviolet_energy
Ultraviolet_Light
Ultraviolet_light
Ultraviolet_Radiation
Ultraviolet_radiation
Ultraviolet_Rays
Ultraviolet
:''Note: Ultraviolet (TV miniseries) is also the name of a 1998 United Kingdom television miniseries about vampires.'' ---- Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-ray. It can be subdivided into near UV (380–200 nanometre wavelength) and extreme or vacuum UV (200–10 nm). When considering the effects of UV radiation on human health and the environment, the range of UV wavelengths is often subdivided into UVA (380–315 nm), also called Long Wave or "blacklight"; UVB (315–280 nm), also called Medium Wave; and UVC (280-10 nm), also called Short Wave or "germicidal". See 1 E-7 m for a list of objects of comparable sizes. The name means "beyond violet" (from Latin ''ultra'', "beyond"), violet (color) being the color of the shortest wavelengths of visible light. Some of the UV wavelengths are colloquially called black light, as it is invisible to the human eye. Some animals, including birds, reptiles, and insects such as bees, can see into the near ultraviolet. Many fruits, flowers, and seeds stand out more strongly from the background in ultraviolet wavelengths as compared to human color vision. Many birds have patterns in their plumage that are invisible at usual wavelengths but seen in ultraviolet, and the urine of some animals is much easier to spot with ultraviolet. [[Image:SOHO_EIT_ultraviolet_corona_image.gif|thumb|right|256px|The sun corona as seen in "deep" ultraviolet light at 17.1 nanometer by the Extreme ultraviolet Imaging Telescope instrument aboard the Solar and Heliospheric Observatory spacecraft]] The Sun emits ultraviolet radiation in the UVA, UVB, and UVC bands, but because of absorption in the Earth's atmosphere's ozone layer, 99% of the ultraviolet radiation that reaches the Earth's surface is UVA. (Some of the UVC light is responsible for the generation of the ozone.) Ordinary glass is transparent to UVA but is opaque to shorter wavelengths. fused quartz, depending on quality, can be transparent even to vacuum UV wavelengths. The onset of vacuum UV, 200 nm, is defined by the fact that ordinary air is opaque below this wavelength. This opacity is due to the strong absorption of light of these wavelengths by oxygen in the air. Pure nitrogen (less than about 10 ppm oxygen) is transparent to wavelengths in the range of about 150–200 nm. This has wide practical significance now that semiconductor manufacturing processes are using wavelengths shorter than 200 nm. By working in oxygen-free gas, the equipment does not have to be built to withstand the pressure differences required to work in a vacuum. Some other scientific instruments, such as circular dichroism spectrometers, are also commonly nitrogen purged and operate in this spectral region. == Discovery == Soon after infrared radiation had been discovered, the German physicist Johann Wilhelm Ritter began to look for radiation at the opposite end of the spectrum, at the short wavelengths beyond violet. In 1801 he used silver chloride, a light-sensitive chemical, to show that there was a type of invisible light beyond violet, which he called chemical rays. At that time, many scientists, including Ritter, concluded that light was composed of three separate components: an oxidising or calorific component (infrared), an illuminating component (visible light), and a reducing or hydrogenating component (ultraviolet). The unity of the different parts of the spectrum was not understood until about 1842, with the work of Macedonio Melloni, Alexandre-Edmond Becquerel and others. During that time, UV radiation was also called "actinic radiation". == Health effects == [[Image:DNA UV mutation.gif|thumb|right|350px|Ultraviolet photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent bases bond with each other, instead of across the "ladder". This makes a bulge, and the distorted DNA molecule does not function properly.]] In general, UVA is the least harmful, but can contribute to the aging of skin, DNA damage and possibly skin cancer. It penetrates deeply and does not cause sunburn. Because it does not cause reddening of the skin (erythema) it cannot be measured in the SPF testing. There is no good clinical measurement of the blocking of UVA radiation, but it is important that sunscreen block both UVA and UVB. High intensities of UVB light are hazardous to the eyes, and exposure can cause ''welder's flash'' (photokeratitis or arc eye). UVA, UVB and UVC all can damage collagen fibers and thereby accelerate aging of the skin. halogen lamp have bulbs made of quartz, not of ordinary glass. Tungsten-halogen lamps that are not filtered by an additional layer of ordinary glass are a common, useful, and possibly dangerous, source of UVB light. UVA light is known as "dark-light" and, because of its longer wavelength, can penetrate most windows. It also penetrates deeper into the skin than UVB light and is thought to be a prime cause of wrinkles. UVB light in particular has been linked to skin cancers such as melanoma. The radiation ionizes DNA molecules in skin cells, causing covalent bonds to form between adjacent thymine bases, producing thymidine dimers. Thymidine dimers do not base pair normally, which can cause distortion of the DNA helix, stalled replication, gaps, and misincorporation. These can lead to mutations, which can result in cancerous growths. The mutagenicity of UV radiation can be easily observed in bacterium cultures. This cancer connection is the reason for concern about ozone depletion and the ozone hole. UVC rays are the strongest, most dangerous type of ultraviolet light. Little attention has been given to UVC rays in the past since they are normally filtered out by the ozone layer and do not reach the Earth. Thinning of the ozone layer and holes in the ozone layer are causing increased concern about the potential for UVC light exposure, however. A positive effect of UV light is that it induces the production of vitamin D in the skin. Grant (2002) claims tens of thousands of premature deaths occur in the US annually from cancer due to insufficient UVB exposures (apparently via vitamin D deficiency). Another effect of vitamin D deficiency is osteomalacia, which can result in bone pain, difficulty in weight bearing and sometimes fractures. Ultraviolet radiation has other medical applications, in the treatment of skin conditions such as psoriasis. UVB and UVA radiation can be used, in conjunction with psoralens (PUVA treatment). ===Protection=== As a defense against UV radiation, the body tans when exposed to moderate (depending on human skin color) levels of radiation by releasing the brown pigment melanin. This helps to block UV penetration and prevent damage to the vulnerable skin tissues deeper down. Suntan lotion that partly blocks UV is widely available (often referred to as "sun block" or "sunscreen"). Most of these products contain an "SPF rating" that describes the amount of protection given. This protection applies only to UVB light. In any case, most dermatologists recommend against prolonged sunbathing. It is advisable to use protective eyewear when working with ultraviolet radiation, especially short wave ultraviolet. Ordinary eyeglasses give some protection. Most plastic lenses give more protection than glass lenses. Some plastic lens materials, such as polycarbonate, block most UV. There are protective treatments available for eyeglass lenses that need it to give better protection. The most important reason that ordinary eyeglasses only give limited protection, however, is that light can reach the eye without going through the lens. Full coverage is important if the risk from exposure is high. Full coverage eye protection is usually recommended for high altitude mountaineering, for instance. Mountaineers are exposed to higher than ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice. == Uses == UV light has many various uses. Some of them are as follows: ===Black lights=== A black light is the name commonly given to a lamp emitting almost entirely long wave UV radiation and very little visible light. Ultraviolet radiation itself is invisible, but illuminating certain materials with UV radiation prompts the visible effects of fluorescence and phosphorescence. Black light testing is commonly used to authenticate antiques and bank notes. It is extensively used in non-destructive testing (NDT); fluorescing fluids are applied to metal structures and illuminated with a black light. Cracks and other artefacts can easily be detected. Black lights are used in forensic examination and testing, as naturally fluorescing remnants can be seen. It is also used to illuminate pictures painted with fluorescent colors (preferably on Black Velvet to intensify the illusion of self-illumination). The fluorescence it prompts from certain textile fibers is also used as a recreational effect (as seen for instance in the opening credits of the James Bond film A View to a Kill). ===Fluorescent lamps=== Fluorescent lamps produce UV radiation by the emission of low-pressure mercury (element) gas. A phosphorescent coating on the inside of the tubes absorbs the UV and becomes visible. The main mercury emission wavelength is in the UVC range. Unshielded exposure of the skin or eyes to mercury arc lamps that do not have a conversion phosphor is quite dangerous. The light from a mercury lamp is predominantly at discrete wavelengths. Other practical UV sources with more continuous emission spectra include Xenon flash lamps (commonly used as sunlight simulators), deuterium arc lamps, mercury-xenon arc lamps, metal-halide arc lamps, and tungsten-halogen incandescent lamps. ===Pest control=== Ultraviolet fly traps are used for the elimination of various small flying insects. They are attracted to the UV light and are killed using an electrical shock or trapped once they come into contact with the device. ===Spectrophotometry=== UV/VIS spectroscopy is widely used as a technique in chemistry, for analysis of chemical structure, most notably conjugated systems. UV radiation is often used in visible spectrophotometry to determine the existence of fluorescence a given sample. ===Astronomy=== In astronomy, very hot objects preferentially emit UV radiation (see Wien's law). However, the same ozone layer that protects us causes difficulties for astronomers observing from the Earth, so most UV observations are made from space. (see UV astronomy, space observatory) ===Analyzing minerals=== Ultraviolet lamps are also used in analyzing minerals, gemstone, and in other detective work including authentication of various collectibles. Materials may look the same under visible light, but fluorescence to different degrees under ultraviolet light; or may fluoresce differently under short wave ultraviolet versus long wave ultraviolet. UV fluorescent dyes are used in many applications (for example, biochemistry and forensics). The fluorescent protein Green Fluorescent Protein (GFP) is often used in genetics as a marker. Many substances, proteins for instance, have significant light absorption bands in the ultraviolet that are of use and interest in biochemistry and related fields. UV-capable spectrophotometers are common in such laboratories. ===Photolithography=== Ultraviolet radiation is used for very fine resolution photolithography, a procedure where a chemical known as a photoresist is exposed to UV radiation which has passed through a mask. The light allows chemical reactions to take place in the photoresist, and after development (a step that either removes the exposed or unexposed photoresist), a geometric pattern which is determined by the mask remains on the sample. Further steps may then be taken to "etch" away parts of the sample with no photoresist remaining. UV radiation is used extensively in the electronics industry because photolithography is used in the manufacture of semiconductors, integrated circuit components and printed circuit boards. ===Checking electrical insulation=== A new application of UV is to detect corona discharge (often simply called "corona") on electrical apparatus. Degradation of insulation of electrical apparatus or pollution causes corona, wherein a strong electric field ionizes the air and excites nitrogen molecules, causing the emission of ultraviolet radiation. The corona degrades the insulation level of the apparatus. Corona produces ozone and to a lesser extent nitrogen oxide which may subsequently react with water in the air to form nitrous acid and nitric acid vapour in the surrounding air. [http://www.seeing-corona.com/] ===Sterilization=== Ultraviolet lamps are used to sterility workspaces and tools used in biology laboratories and medical facilities. Conveniently, low pressure mercury discharge lamps emit about 50% of their light at the 253.7 nm mercury emission line which coincides very well with the peak of the germicidal effectiveness curve at 265 nm. UV light at this wavelength causes adjacent thymine molecules on DNA to dimerize, if enough of these defects accumulate on a microorganism's DNA its replication is inhibited, thereby rendering it harmless. Since microorganisms can be shielded from ultraviolet light in small cracks and other shaded areas, however, these lamps are used only as a supplement to other sterilization techniques. ===Disinfecting drinking water=== Ultraviolet radiation is increasingly being used to disinfect drinking water and in waste water treatment plants. Recently it was discovered that ultraviolet radiation could treat Cryptosporidium, previously unknown. The findings resulted in two [http://www.calgoncarbon.com/company/news/index.cfm?mode=detail&id=DF8B2807-AB22-705E-D9769AEA0B6A744E US patents] and the use of UV radiation as a viable method to treat drinking water. === Food Processing === As consumer demand for fresh and "fresh like" food products increases, the demand for a nonthermal method of food processing is likewise on the rise. In addition, public awareness regarding the dangers of food poisoning is also raising demand for improved food processing methods. Ultraviolet radiation is used in several food processes to remove unwanted microorganisms. UV light can be used to pasteurization fruit juices by pumping the juice over a high intensity ultraviolet light source. The effectiveness of such a process depends on the UV absorbance of the juice. ===Fire detection=== Ultraviolet (UV) detectors generally use either a solid-state device, such as one based on silicon carbide or aluminum nitride, or a gas-filled tube as the sensing element. UV detectors which are sensitive to UV light in any part of the spectrum respond to irradiation by sunlight and artificial light. A burning hydrogen flame, for instance, radiates strongly in the 185 to 260 nanometre) range and only very weakly in the IR region, while a coal fire emits very weakly in the UV band yet very strongly at IR wavelengths; thus a fire detector which operates using both UV and IR detectors is more reliable than one with a UV detector alone. Virtually all fires emit some radiation in the UVB band, while the Sun's radiation at this band is absorbed by the Earth's atmosphere. The result is that the UV detector is "solar blind", meaning it will not cause an alarm in response to radiation from the Sun, so it can easily be used both indoors and outdoors. UV detectors are sensitive to most fires, including hydrocarbons, metals, sulfur, hydrogen, hydrazine, and ammonia. Arc welding, electrical arcs, lightning, X-rays used in nondestructive metal testing equipment (though this is highly unlikely), and radioactive materials can produce levels that will activate a UV detection system. The presence of UV-absorbing gases and vapors will attenuate the UV radiation from a fire, adversely affecting the ability of the detector to "see" a flame. Likewise, the presence of an oil mist in the air or an oil film on the detector window will have the same effect. ===Curing of adhesives and coatings=== Certain adhesives and coatings are formulated with photoinitiators. When exposed to the correct wavelengths of UV light, polymerisation occurs, and so the adhesives harden or cure. Usually, this reaction is very quick, a matter of a few seconds. Applications include glass and plastic bonding, and the coating of flooring. ==See also== * UV index ==References== * Grant, William B. (2002). [http://www3.interscience.wiley.com/cgi-bin/abstract/91016211/ABSTRACT An estimate of premature cancer mortality in the US due to inadequate doses of solar ultraviolet-B radiation.] ''Cancer'' 94 (6), 1867–1875. * Matsumura Y, Ananthaswamy HN (2004). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15020192 Toxic effects of UV radiation on the skin.] ''Toxicol. Appl. Pharmacol.'' 195 (3), 298-308. * Hu S, ''et al.'' (2004). [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15262692 UV radiation and melanoma in US Hispanics & blacks.] ''Arch Dermatol.'' 140 (7), 819-824. Electromagnetic spectrum
Ultraviolet
What is the source of this claim? *Ultraviolet light is the cause of [skin cancers]? such as melanoma?. The radiation ionises DNA molecules in skin cells, causing mutations which can result in cancerous growths. I am going to label it an "environmentalist fear" if I can't find any science to back it up. (I'll look myself; I won't be hasty.) -- User:Ed Poor Ed -- what IS it with you? My goodness. It seems that every time you see something you don't agree with, you pigeonhole it into "beliefs of Liberals" "beliefs of environmentalists" -- as if those are by definition Bad Things. I can't quote any particular scientist, but I'm pretty sure that the AMA and the Dermatology and Oncology boards would agree to a link between UV rays and melanoma. Why do I think this? Because every time I go to the doctor, and especially to the dermatologist, I see pamphlets and posters warning me about not wearing sun block and staying out of the sun when UVA and UVB rays are most intense, in order to minimize the risk of skin cancer. Why don't you just change the bloody thing to "has been linked to skin cancer", rather than pulling your usual namecalling act? user:JHK :Are you calling me a "namecaller"? User:Ed Poor I agree. I'm hardly an environmentalist myself, and would probably apall a greenpeacer if I got into a discussion with them, but I have with my own two hands conducted experiments in which I used UV light to induce mutations in bacteria. To say that it's some sort of environmentalist fearmongering is inane. user:Bryan Derksen :(I should mention, though, that it may be reasonable to bring up issues about the ''magnitude'' of the risk caused by UV exposure. That's something which is indeed sometimes blown all out of proportion. But please, find some actual numbers before doing that.) user:Bryan Derksen Bryan, please add something about bacteria mutations, at least one sentence! :Alright, but I'll have to dig out some very old notes first. It's something I did back in an undergrad genetics lab. :) user:Bryan Derksen Also, I am not disputing the contention that UV can cause cancer. I am only asking for sources. I want to distinguish between: #scientific sources that have proved something (or at least found it to be highly likely), and #claims by advocacy groups. For instance, does UV cause melanoma or non-melanome cancers? How much UV exposure will cause cancer? Is there a threshold over which most people will get a cancer? Or have studies (cite them, please) found an increased rate of cancer at various exposure levels? E.g., double the UV, and the annual cancer rate increases from 100 per million to 180 per million. Please don't misunderstand. I don't want to suppress science! I only want to label advocacy and distinguish it from science. User:Ed Poor ---- You're demanding a lot of tedious legwork documenting scientific consensus. Or would you accept "Karen Landau, M.D. (personal communication)" as a source? You say you don't dispute the statement--and then want people to run around proving it anyway. If you're questioning a scientific consensus, the onus is on you to provide citations: studies that (for example) compared different levels of UV exposure and found no increase in cancer. user:Vicki Rosenzweig ---- I did some legwork (just before reading the above). I found a report by WMO, UNEP, NOAA and NASA which said that: *When high-quality measurements have been made in other areas far from major cities and their associated air pollution, decreases in ozone have regularly been accompanied by increases in UV-B. [http://www.al.noaa.gov/WWWHD/Pubdocs/Assessment98/faq8.html] However, they did not give any source for this data. They just show a pretty graph. Given the amount of advocacy over this issue, I hesitate to call this "scientific" The report concedes that: *From 1979 to 1997, the observed losses in the amount of ozone overhead have totaled about 5-6% for northern midlatitudes in winter and spring, about 3% for northern midlatitudes in summer and fall, and about 5% year round for southern midlatitudes. [http://www.al.noaa.gov/WWWHD/Pubdocs/Assessment98/faq10.html] Based on my visual estimate of the slope of their graph [], I estimate that this would cause an increase of 1% to 2% in surface UV radiation. This is less than the increase you would get by driving 30 miles closer to the equator. This pales in comparison with flying from Maine to Florida for your summer vacation. User:Ed Poor :Ed -- you're working out of context -- again. The quote you claim to object to says UV causes melanoma. Your "evidence" relatesz to the hole in the ozone layer and the increase in UVB rays -- not at all the same thing. Please try to stopy going into articles band making objections based on your ''a priori'' beliefs. Articles aren't research projects. Things that are generally accepted, such as the fact that spending lots of time in the sun without protection increases the risk (and some say causes) melanoma, are perfectly acceptable. And if you're going to do legwork, as you call it, please make sure it's relevant. user:JHK ---- My comment to Vicky might be on the wrong talk page (elsewhere I said that there is overlap between CFC, ozone, and UV pages). The question I am interested in is whether CFC emissions are a significant cause of cancer. This has a bearing on whether the Montreal Protocol is good or bad, something the wikipedia will not take sides on; but which its readers will want to decide based on information the wikipedia provides. Are you aware of any scientific evidence supporting the hypothesis that CFC emissions cause ozone depletion, leading to increased surface UV radiation and increased incidence of cancer? If so, please point me to it. I would love to put this info in the wikipedia! User:Ed Poor :That's not the point, Ed. That isn't what you mentioned above, and is part of another article. This is just another of your tedious attempts to create debate -- and not the scholarly kind. As I understand wikipedia policy, this is neither a place for original research, nor for the bulletin-type fora you seem to prefer. If anybody had the time to do the research, I'm fairly sure that he could find scientific articles in peer-reviewed journals that support both positions. The fact that the US and other countries all agreed to lower CFC emissions indicates that there is at least some reason to accept that there are links. Please stop threatening to destroy other people's work "unless they can provide proof." This is just a slightly veiled attempt on your part to present the world according to Ed. That is hardly collegial, and certainly a perversion of the Wiki-way. user:JHK When there are scientific articles in peer-reviewed journals that support both positions an an issue, why not point these out? I think this is the best thing to do when writing an encyclopedia article about scientific questions which researchers have not settled yet. We should distinguish between (A) advocacy based on fear and (B) the findings of science. For example, some people advocate mandatory HIV testing, reporting positive results to public health authorities and quarantine -- based on the fear that AIDS will spread unchecked otherwise. The reason for their advocacy is their fear of an AIDS epidemic. On the other hand, there is the question of what causes AIDS and how its method of contagion. These are scientific questions, which can and should be considered separately. Based on the science, as well as other considerations, advocates make public policy recommendations. Before we debate further, would you please tell me what parts of the above you agree with, Dr. K? User:Ed Poor :Well there's an unclear question. I'm not sure which part of the "above" I should be looking at. Ed, I'm not here to enter into your debating society. I've already come to the conclusion that discussion with you is fairly meaningless, because I have yet to see one contribution you have made that is from the beginning NPOV and because, whether or not you admit it, every initial stub you post is based on what you call "advocacy" -- although in your book things seem to be either "as Ed sees them (the right way)" and "advocates (liberal, loony left, environmentalist...i.e. wrong according to Ed)." I have yet to see you begin with an empirical approach. :Moreover, I find it interesting that, when it's science vs. religion, science is wrong in your book (see evolution, etc.), but when you are trying to limit the expression of a consensus viewpoint that you deem "liberal", "environmentalist", "feminist" or whatever "lesser" advocacy, you scream, "show me the scientific proof!" In my religion, hypocrisy is a kind of sin...I guess that the UC doesn't see it that way. :I also find it interesting that you are always so sure that you are right. I ''am'' actually an expert in my fields, and know a whole lot more than the average person in several other fields, mostly because I have the opportunity to discuss things (in modern history, art history, literature, etc.) with people who are experts. Despite the fact that I know my stuff, I usually check and make sure that new articles I produce and edits I make are correct, because I know I am fallible. But then, I live in a world where we have the obligation to prove ourselves right (sometimes despite other opinions), not in the Ed world, where others have an obligation to prove, not only that Ed's views are right or wrong, but that other legitimate views even exist. I don't actually care enough about this stuff to research it. I care about maintaining a high standard of article and using an appropriate scholarly approach. I only involve myself in this nonsense because your approach to contibutions belittles, and often negates, all the intellectual values (like objectivity and honesty) I have held dear for all of my academic life. user:JHK I am usually right: it's my outstanding characteristic. One of the things I'm right about is the need for sources to back up claims; that's what distinguishes science from mere advocacy. Scientists feel an obligation to explain their findings, even to share their data. They welcome attempts by other to duplicate their results. Only the dishonest or incompetent ones bristle at the suggestion they may have erred. Getting back to the article, I'd like to see just a little bit more of the science of UV and cancer: how much UV, what sort of cancer. I personally consider UV dangerous and would never consider lying on a beach all day sunbathing. However, if I lived in Florida I wouldn't move to Alaska just to reduce my UV exposure by 90%. I'll be happy with the UV-cancer connection when the article provides statistics relating UV levels and the annual number of skin cancer cases. What's so hard about that? User:Ed Poor ---- The astronomy paragraph refers to the shielding by the ozone layer, which has not been introduced. Therefore the current order of the paragraph doesn't make sense and I changed it, Ed changed it back, and I change it again. Ed, give a reason for your preferred order of paragraphs. user:AxelBoldt Your order is better. I am going to move the CFC-ozone-UV-cancer hypothesis out of the article completely, anyway, and put it where it belongs. But not today. I have to consolidate all the info first (a lot of leg work). User:Ed Poor :The UV-cancer connection most certainly belongs into this article and should stay here. user:AxelBoldt ---- ---- Ed, I did a search on the internet for a site that might help clarify some of the health hazards that ultraviolet radiation can cause. I'm not sure if you've seen this site and discounted the results so far or not, but if you haven't, you might find it of interest. http://www.ciesin.org/TG/HH/ozhlthhm.html The problem with science and the public has always been that results that show connections such as you're searching for tends to be published in journals the public rarely reads, and when it does make its way out into the public, non-scientists are the ones doing the interpreting, and of course reading it with their biases. You asked for a connection between CFCs and skin cancer. What you need to actually do is find that CFCs cause depletion in the Ozone layer, which then causes more UV radiation, which causes cancer. I've given one link, after about 3 minutes of checking, maybe I'll look for others at a later date. Another 'interesting' (to me far more apalling than skin cancer in humans) statement I've seen made, and I think is believed by many Marine Biology folks, is that all coral reefs in the world will be gone in 50 years due to increased UV levels. This while arguments continue as to whether scientists have proof or just correlations at the moment. For another case which makes me believe that caution over convenience when science shows a possible correlation, should be the order of the day is the ''Pfisteria'' outbreaks that occurred in NC. I won't go into huge detail, but you might find it interesting Ed... In NC and MD, ''Pfisteria'' outbreaks both occurred around the same time. In MD, it only took a few hundred fish killed with open sores and a handful of fishermen coming down with neurological symptoms for the state government to jump in on a water cleansing program _while_ the science was still going on. In NC, it took millions of dead fish over a few years, and hundreds of people with neurological symptoms (some to the extent where brilliant scientists could no longer count, and people couldn't remember what they were beginning to say at the start of their sentences) before the government even admitted there might be a problem. I realize it's not the goal of the Wikipedia to put forth ideas in order to change the way society handles CFCs or other potentially harmful items, but the thought of no more coral reefs in 50 or so year makes me much less sympathetic to those who have the attitude of "science jumps the gun, all they have is theories not proofs, let's wait and see further evidence first." user:Rgamble ---- Ed, take a look at this link. It's within the same page that I mentioned above. You said you wanted a scientific paper that discussed the matter. Here you go: http://www.ciesin.org/docs/001-503/001-503.html There's another article or two that aren't online, but have their references listed, so you can go check them out. user:Rgamble ---- Scientific American has a good article for the layperson at, http://www.sciam.com/0996issue/0796leffell.html to which I refer interested parties. I also have some observations on the above debate which I believe belong in user talk:Ed Poor and so am putting them there. ---- Anyway ... The article is presently, to my mind, unclear: :The major component of the sun's light is UV-B, but because of absorption in the atmosphere's ozone layer, 99% of the ultraviolet light that reaches the Earth's surface is UV-A. The peak of the sun's energy is in middle of the visible spectrum (I even did a Wien's law calculation to check). It may be that the majority of the sun's ''ultraviolet'' emission is in UV-B (though looking at the blackbody curve I have my doubts about that as well), but the wording "major component of the sun's light" suggests that the majority of the sun's total EM emission is in the UV-B band, which I'm almost certain isn't correct. I haven't changed the article because my brain's melting at the moment and I'm not sure I haven't missed something, but I just wanted to flag it up.User:Bth :I think you're right, that paragraph is incorrect. In fact, it's wrong two ways: Not only is the peak solar emission in the visible (~580 nm), but also there's much more UV-A than UV-B, and it's mostly '''UV-B'' that gets absorbed by the atmosphere (see [http://www.phys.ksu.edu/gene/e1f2.html]). :Definitely needs changing. User:DrBob ::Done.--User:Bth ---- Why is this at ultraviolet instead of ultraviolet radiation? I would think if somebody wanted to shorten the name, they would just use UV. User:Pizza Puzzle ---- I made a change to this article yesterday, before I knew about this talk page. (I'm pretty new to Wikipedia.) Having now read this discussion, I'm wondering why some of the references discussed here aren't mentioned in the article. Is my lonely reference inappropriate? I certainly don't want to give the impression that UV radiation has only positive effects on human health! If it's OK, what's the right way to do internal footnotes (i.e. a little label '[n]' that links to the References section of the article)? I was trying to follow the Proposed Citation Style in wikipedia:Cite your sources, but maybe that's not the right format. Thanks, User:Mignon 18:47, 31 Dec 2003 (UTC) == Ultraviolet as a color == Do you know of any way to modify our eyes so that ultraviolet is visible to us as a color?? This should be known by 2100. :Sure -- use an instrument that translates UV into colors we can see, perhaps in the form of goggles if you want something wearable. Modifying eyeballs themselves to be UV-sensitive isn't impossible theoretically, but it's a huge can of worms since it would require changing our brains as well to make sense of the information. It seems likely to me that if we ever acquire the technology to do that, mere ultravision would be one of the least of the useful applications. (By the way, why 2100 in particular? And why ultravision, for that matter? I'm genuinely curious about your interest.) ::I doubt you'd need to change your brain to make sense of the information. I would think the easiest method to accomplish this would be to simply genetically modify the DNA which codes for the manufacture of the rhodopsin molecules in the retina's cone cells to be a slightly different shape so they are sensitive to UV light. Say for example you do this to the blue light detecting cones in the eye, the brain would simply process UV light then as "blue", to be sure, you'd see a much different world as percieved colors would be all wrong, but it would work I think.--User:Deglr6328 23:24, 12 Aug 2004 (UTC) :::Blue cones are already somewhat sensitive to UV light (at near-visible wavelengths anyway; see cone cell) but the lens and cornea absorb too much below 380 nm for this to be useful. There's a story I've heard of a chemist who had eye surgery which resulted in a much thinner cornea than usual, and afterwards he was able to align UV spectrometers visually, so maybe there are people around with "ultravision" already. -- User:DrBob 23:36, 12 Aug 2004 (UTC) ::::Hmmm, interesting thoughts. :o) Incidentally, I have also heard of the early discoverers/tinkerers of X-rays claiming that when they placed a closed eye in front of an X-ray tube they were able to percieve a faint blue/purple glow, directly seeing the X-rays. I have to say that I don't find this altogether implausable, and I've contemplated adding it to the X-rays article but I can't find where I originally read it and I need to know if it was reputable or not.--User:Deglr6328 19:53, 14 Aug 2004 (UTC) == Does UV exposure cause Melanoma? == The notion that UV exposure causes "skin cancer" seems well supported by the fact that we see basal and squamous cell skin cancers in areas where there is the chronic skin damage, especially sun-related damage. There is not good evidence at all that UV exposure causes melanoma, though, which is the most deadly of the skin cancers, although there is a widespread acceptance among the medical profession that it does. This is really an unupported belief, and the only evidence is epidemiologic: melanoma is more common near the equator. However melanoma is not very related to sun-exposed areas of skin, and one has to propose that sun exposure somehow alters the immune system to create cancers distal to the area of the body exposed to sun. This is sort of a hypothesis to support a hypothesis, and not very convincing. Nevertheless, the UV-Melanoma dogma is deeply ingrained, and is not likely to go away soon just because there is no evidence to support it. If any of your medical buddies insists that UV exposure causes melanoma, ask them whether or not these lethal skin cancers are most commonly found in the most sun-exposed areas of the body. If they don't have a cogent reply they are probably just parroting what they have been taught. ==disputed== "A black light is a lamp emitting only UV light and no visible light." :If that's true, then there are no black lights. Or are cameras just picking up on UV and converting it to fuschia and violet? User:Lysdexia 03:43, 22 Nov 2004 (UTC) *Changed this. Better now.--User:Deglr6328 06:41, 22 Nov 2004 (UTC) "A UV flame radiates in the 185 to 245 nanometre (1850 to 2450 angstrom) range." :What's the context? UV is wider than that. Where are these UV flames? User:Lysdexia 03:55, 22 Nov 2004 (UTC) == UV and Sunburn == In the paragraph, Health effects, of ultraviolet article, it mentions "In general, UVA is the least harmful, but can contribute to the aging of skin, DNA damage and possibly skin cancer. It penetrates deeply and does not cause sunburn.". But in the sunscreen article, it mentions "The best sunscreens block both UV-A and UV-B rays, both of which can cause sunburn.". Would anyone be kind to tell me which one is true? :The first is true, if you define ''sunburn'' as visible damage. I fixed the second article. --User:Heron 08:43, 4 Jun 2005 (UTC) == Ultrapink light == I recently took a picture of my black light with my digital camera. Normaly, when you look at my light, it is purple, but in my digital camera's photo, it was pink. Also, on a side note, in the photo, I was wearing a white shirt which made it glow. It glowed the same blue in both my eyes and the photo, yet the black light was pink. Why? :The colored filters used in the Bayer mask of the digicam's ccd do not have the same optical properties as do the rhodopsin molecules in your eye. The CCD is somewhat sensitive to UV and the colored filters of the mask in front of it behave nonintuitively outside the visible spectrum. In this case the red filter was obviously more transparent to the UV than the green and blue filter materials thus making the camera "think" there's more red light coming from the black light and giving it a pink hue. The reason your shirt is the same color in the photo and to your eye is simple. The cotton in your shirt was fluorescent, it was only emitting blue light, not UV, and therefore the camera has no trouble correctly rendering it. If you have an electric stove, turn it on and let the coil heat up, then turn it off and switch the room lights off. Wait till the coil is no longer glowing very brightly and take a picture(no flash!), if your camera lacks a proper infrared filter you will see a neat effect. --User:Deglr6328 01:26, 3 Jun 2005 (UTC) :: What a nice reply! Maybe the anonymous poster of the question could attach the picture? I'm curious to see it. User:Common Man 05:51, 3 Jun 2005 (UTC) :Thanks for the answer. I'll paste a picture tomorrow. 6/3/05 :Sorry, but I can't figure out how to edit the page correctly, so I will just give you the html to the image. http://en.wikipedia.org/wiki/Image:DSCN1187.JPG
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