Wikipedia:Reference desk/Archives/Science/2011 June 16

= June 16 =

physics questions
what is "Akash"? — Preceding unsigned comment added by Qwshubham (talk • contribs) 07:51, 16 June 2011 (UTC)


 * Akash is the Sanskrit word for aether. Although there were aether theories in early modern physics, in particular the luminiferous aether theory, those theories have long since been discarded, and are not a part of modern physics.  Red Act (talk) 08:08, 16 June 2011 (UTC)


 * Well, although that name isn't used any more, there may very well be a substance in the apparent vacuum of space that isn't obvious. For example, there's the dark matter theory. StuRat (talk) 08:41, 16 June 2011 (UTC)


 * I don't know about its use in physics, but if this question was on the language desk I would point out that the word is more generally used to mean the sky or space.--Shantavira|feed me 11:54, 16 June 2011 (UTC)

Lunar Eclipse - yet another q?
Im sure mankind has been fascinated with eclipses and there are many questions which have been asked about eclipses and many more questions might continue to asked. Please excuse me even if my question sounds trivial... I was watching last night's lunar eclipse and I got a brilliant view from the comfort of my living room sofa which has these huge french windows and right in front of me I could see the entire eclipse... Though Im a doctor and belive most of the scintific explanations behind all actions in our life, I dont blindly follow what science says. I always try to reason it out rather than take it as a dictum. What I noticed was just by the side of the moon on all sides I could see the starry sky very brilliantly and only the moon was obscured by this grayish reddish cape. If the lunar eclipse really does happen because of earths shadow covering the moon, then why is it during eclipse several stars just adjacent to the moon are very clearly visible ( the stars being so faint and distant) yet the much more closer, much more bigger and brigter moon was totally hidden and appeared like to be a mere silhouette? In other words, if the shadow of earth is so big and strong to blank out and virtually snuff out the moon, shudnt the entire area of earths shadow black out the stars and planets too in its path?--Fragrantforever 10:40, 16 June 2011 (UTC) — Preceding unsigned comment added by Fragrantforever (talk • contribs)
 * Cause the stars emit their own light and the moon doesn't -- the Earth's shadow blocks the Sun's light from reaching the moon, not the light reflected from the moon to the earth. 67.169.177.176 (talk) 10:55, 16 June 2011 (UTC)
 * It is either impossible to have eclispe with other planets. The shadow of the earth is cone shapped as you can see in the article lunar eclipse. Only very close objects (like the moon) can enter this shadow cone. This shadow cone is rougthly 5 times longer as the distance between earth and moon--Franssoua (talk) 10:59, 16 June 2011 (UTC)
 * Actually, the umbra just barely touches Earth, and sometimes it doesn't reach, forming an annular eclipse. Now the transit of Mercury or transit of Venus also produces an "annular eclipse" of sorts - but you need good equipment to be able to see the tiny shadow against the Sun.  The other planets never come between Earth and the Sun, but Earth comes between the Sun and them, and indeed its shadow does affect them in the sense that the transit of Earth is visible from their perspective, again as just a tiny black dot crossing the Sun.  (I don't think even machines have observed one from the surface of another planet, but they have from space) Wnt (talk) 15:10, 16 June 2011 (UTC)
 * Wnt - you are confusing solar eclipses with lunar eclipses. The length of the Earth's umbra is about 3.5 times the distance to the Moon, as can be seen from geometry and similar triangles:
 * $$\text{Length of Earths umbra}=\frac{\text{Radius of Earth}}{\text{Radius of Sun}} \times 1 \text{ AU} = \frac{1}{109} \text{ AU}$$
 * $$\text{Radius of Moons orbit} = 0.00257 \text{ AU}$$
 * $$\frac{\text{Length of Earths umbra}}{\text{Radius of Moons orbit}} = \frac{1}{109 \times 0.00257} \approx 3.57 $$
 * Lunar eclipses can be total, partial or penumbral but they are never annular. Gandalf61 (talk) 15:42, 16 June 2011 (UTC)
 * $$\frac{\text{Length of Earths umbra}}{\text{Radius of Moons orbit}} = \frac{1}{109 \times 0.00257} \approx 3.57 $$
 * Lunar eclipses can be total, partial or penumbral but they are never annular. Gandalf61 (talk) 15:42, 16 June 2011 (UTC)


 * You're right - I was talking almost entirely about solar eclipses - not sure how I missed the obvious "lunar" up there! Wnt (talk) 16:59, 16 June 2011 (UTC)
 * You don't need good equipment to see a transit of Venus. I observed the last one with just a pair of binoculars and a piece of paper (by projecting onto the paper - hopefully I don't need to say it, but you should never look at the sun through binoculars). It would have helped if I'd had a tripod or something to hold the binoculars steady, but I could easily see the silhouette of Venus even though it was shaking all over the place. Mercury is a little more difficult - I saw the 2003 transit, but that was through a small (filtered) telescope. --Tango (talk) 18:15, 16 June 2011 (UTC)


 * Transits of the Earth over the Sun are often observable from Mars provided you have the right equipment–Mars is about 200 times farther away from the Earth than the Moon. Now, when you get to the distance of stars, the closest star, Proxima Centauri, is more than 100 million times farther away from Earth than the Moon, and either way the puny Earth's shadow would have no effect. This is why the Milky Way is more visible during a total eclipse from the countryside, and why occultations of stars by the Moon are more easily apparent during eclipses. ~ AH1 (discuss!) 15:38, 18 June 2011 (UTC)

Foil wrapped for freshess
Do foil wrappers, crisp packets etc actually "lock in" freshness better than regular, properly sealed plastic could? Or was/is it just a ploy? --129.215.5.255 (talk) 11:06, 16 June 2011 (UTC)


 * Foil would reflect some light and heat. This could make a difference. Zzubnik (talk) 11:23, 16 June 2011 (UTC)


 * The plastics used for food packaging, like PET, are somewhat permeable to gasses, liquids, and UV radiation. Metallised film treatments dramatically lower this permeability. This allows for longer shelf-life and less spoilage (but no so much from sealing "freshness" in, but keeping stuff out). -- Finlay McWalter ☻ Talk 11:27, 16 June 2011 (UTC)


 * Yes, I remember the days before crisps were in foil packets, when most of the crisps sold in low-turnover shops were either stale or losing their "crispness". Foil keeps out moisture and oxygen, and crisps thus protected can remain edible for years after their sell-by date.    D b f i r s   07:32, 17 June 2011 (UTC)

Solubility and pH
Hello. The solubility of Mg(OH)2 in a particular buffer is 0.65 g/L. The Ksp of this salt is 1.8×10-11. What must be the pH of the buffer? If the buffer does not react with Mg2+ ions, [OH-] = 4.02×10-5. However, for each mole of Mg(OH)2 dissolved, two moles of OH- ions dissociate. Assuming 1 L of volume, the buffer reacts with (2.23×10-2 - 4.02×10-5) moles of OH- ions. So, the buffer pH should be 1.65. The answer key claims 9.60. What have I done wrong? Thanks in advance. --Mayfare (talk) 15:35, 16 June 2011 (UTC)
 * You have made this WAY more complicated than it has to be. All you need to do is find the concentration of the OH- at the given solubility, and find out what pH produces that concentration of OH- Consider the following:
 * If [OH-] = 4.02E-5, and pOH = -log [OH-], then pOH = 4.40
 * Since pH = 14-pOH, then pH = 14-4.40 = 9.60
 * -- Jayron  32  15:53, 16 June 2011 (UTC)

About the Brain
I might have this confused so any help is appreciated. Now, from what I understand, our memories both short term and long term are kept in cells that travel throughout the brain matter or neurons. But what about the things that make up our personality or if we are good at science or math are they also kept in cells? Are the neurons and the brain matter just the keepers of the cells what they are in or on? And when we have an accident to the head or if people do drugs for years and they lose brain cells (or change in personality, since change in brain chemicals) or die off naturally the brain itself remains the same, does it not, it is just the cells or the chemicals coming in and out that change? — Preceding unsigned comment added by 71.137.252.216 (talk) 18:42, 16 June 2011 (UTC)
 * It is a hard question to answer. You may want to start exploring things neuroscience topics in general, to get at the biology end of it, as well as some philosophical ideas, the Hard problem of consciousness and Phenomenology.  From the "brain structure" end, check out Behavioral neuroscience and Cognitive neuroscience.  Personality_psychology has a little bit as well.  Most of what we call "personality" seems to have its origins in the Prefrontal cortex and the Amygdala.  -- Jayron  32  18:58, 16 June 2011 (UTC)


 * I wouldn't say that memories are kept in cells that travel through neurons. They are kept in the neurons and in the synapses that connect them. Electric signals travel through neurons carrying information. Dauto (talk) 19:06, 16 June 2011 (UTC)


 * If it helps, you could think of the cells and the way they're connected as the brain's "hardware", and the electric signals and brain chemicals as the "software". Both are important factors that determine your personality and many other things.  And yes, any kind of brain damage will affect both of these. 67.169.177.176 (talk) 20:30, 16 June 2011 (UTC)


 * You may be interested in nature vs. nurture and inheritance of acquired characteristics. ~ AH1 (discuss!) 15:28, 18 June 2011 (UTC)

Onychogalea
Why Onychogalea evolved a nail tail while other macropods don't?--188.147.5.203 (talk) 18:48, 16 June 2011 (UTC)
 * Evolution doesn't have "whys" beyond "It happened randomly and the trait didn't cause the individuals that had it die off too fast to pass the trait on to their young". -- Jayron  32  19:01, 16 June 2011 (UTC)
 * Note: That answer merely implies that a random trait wasn't harmful to a population. While it's possible that the trait was created through a random walk, it's more likely that it was selected for. In answer to the question: either the trait isn't adaptive in the other macropod populations (i.e. it doesn't add any advantage), or the trait (or an early version of it) randomly appeared in the Onychogalea population, and never appeared in the other populations. &mdash; Sam 166.186.171.173 (talk) 21:04, 16 June 2011 (UTC)


 * Why do people in England speak English while other Europeans don't? Dauto (talk) 19:10, 16 June 2011 (UTC)
 * There are literally scores of non-English-Europeans who speak the English language quite well, as illustrated by the author of this sentence. --Ouro (blah blah) 07:33, 17 June 2011 (UTC)


 * Jayron32's answer means that the trait is not so deleterious that it would quickly vanish from the population. That is indeed the minimum we can safely infer about the (stable) presence of a certain trait in a certain species. However, the nail-tail trait could also be adaptive, meaning that it "enables or enhances the probability of that organism surviving and reproducing"(emphasis mine). See also Adaptation and fitness_(biology). Determining what category this specific trait falls into would require a dedicated research project. SemanticMantis (talk) 19:51, 16 June 2011 (UTC)


 * I think this question is being overthought a bit. The basic question is, does a nail tail do anything useful?  (I don't know the answer, but the obvious approach is to look for whether these species use their tails in a different way from other macropods.) Looie496 (talk) 15:58, 17 June 2011 (UTC)
 * The Wildlife Preservation Society of Queensland says (under "Nailtail function"); "The tail projection possibly helps the animal keep stable or change direction when it travels at high speeds."
 * The State of Queensland (Department of Environment and Resource Management) says; "It is unknown whether the "nail-tail" spur serves a function, but one theory is that it may aid their speed when the spur hits the ground and acts as a point on which the wallaby pivots during sharp turns. The bridled nailtail wallaby's ability to flee at high speed is how they earned their name 'flashjack'." Alansplodge (talk) 00:39, 18 June 2011 (UTC)

Spider monkeys also possess what amounts to a finger tip on their tail. Apparently random mutations which express genes associated with fingers on the tails of arboreal mammals are beneficial. μηδείς (talk) 02:05, 20 June 2011 (UTC)

INFORMATION ON CAPTAFOL
Wikipedia article on captafol says it is no longer used in the U.S. but is used on a variety of crops, which are listed. My question is: Which of these crops are imported into the U.S., in what quantity, and are any credible individuals or government agencies (notice lack of the word "credible" here) monitoring deaths and ill health effects from these captafol-infested products? I am grateful to everyone with an appropriate answer or other information. Thank you. 75.6.40.146 (talk) 19:54, 16 June 2011 (UTC)
 * The Wikipedia article is out of date; the source it cites is from 1996. I will be updating it shortly. According to this paper (a draft, but I assume factual details are correct), most uses in the US were banned in 1999, and no crops grown in the US have been allowed to test positive for captafol since 2006. The linked paper also mentions that a few countries which export to the US still allow its use, but it does not specify which crops these may be. If you're really worried about it, buy local produce.- Running On Brains (talk) 22:42, 16 June 2011 (UTC)
 * This document from the US National Institutes of Health says that captafol was used by some countries up to the mid-2000's, but "by 2010, no countries were identified that still allowed the use of captafol on food crops". Looie496 (talk) 22:44, 16 June 2011 (UTC)
 * Good find Looie, I'll add that to the article. - Running On Brains (talk) 22:50, 16 June 2011 (UTC)
 * To editorialize just a little, I added some information about the patents I found on captafol to the article. Now the patent on synthesis of captafol appears to date to 1965, and the patent on its use in a synergistic spray with another pesticide was filed in 1978.  The production of new captafol (but not use of existing stocks) was banned in 1987, and the use of captafol on most crops was banned in 1999.  Now patents currently run 20 years; in the past there was a slightly different scheme.  But I think we can say that there is a fairly close coincidence of dates here.
 * It is, admittedly a partisan and personal opinion, but I don't think an unreasonable one, to suppose that any new drug, pesticide, sweetener, or other chemical must be proven safe soon after its patent is introduced... and proven unsafe soon after the patent expires. The nice thing is that every few years we have some brand new pesticide proven safe to use on our food, which we can be sure will be found to have been hazardous just about 20 years in the future. Wnt (talk) 00:02, 18 June 2011 (UTC)
 * It is quite cynical indeed to think that. As you say, the production of the pesticide was disallowed in 1987, but this was mainly due to the fact that no one was producing it anymore! The scientists involved have no reason to modify or conceal their results, and if they did, the evidence would be apparent in the details of their study (which, as the National Institutes of Health is a government agency, are freely available to the public). You can see in the Report on Carcinogens that there still is no clear evidence it causes cancer in humans, but its use is being banned out of an abundance of caution, since it has been shown to be carcinogenic at high levels in mice and rats. - Running On Brains (talk) 20:44, 18 June 2011 (UTC)
 * Help me understand your comment: why would any product be disallowed *because* no one is producing it any more? As for my reasoning, either it is dangerous in some way, then it has to be prohibited disregarding if anyone produces it, or is poses no dangers, in which case there is no reason (except perhaps for populism or bribery) to prohibit it. Please correct me if my reasoning lacks some facts or logic. 5BYv8cUJ (talk) 21:19, 18 June 2011 (UTC)
 * You hit the nail right on the head -- in many cases, pesticides that have previously been proven safe are later unjustly "found hazardous" for no other reason except to pander to the green lobby and to the people's exaggerated fear of synthetic chemicals. 67.169.177.176 (talk) 21:31, 20 June 2011 (UTC)

Scratched CD
I have Flight Sim 2004 installed on my computer, which I really enjoy playing on weekends (I know, FSX is the current version, but I really love the Lockheed Vega). This software comes on 4 CD-ROMs, of which CD-ROM #4 has to be inserted into the CD-ROM drive when playing. Last night, I noticed that the #4 CD-ROM has many small scratches on it -- by small, I mean so small that most of them can only be seen under a bright light, but there are many of them. Be that as it may, they do NOT seem to be affecting the gameplay in any way. My question is, do you think this will become a problem if I have to reinstall the program from the CDs for any reason? Thanks in advance! 67.169.177.176 (talk) 20:26, 16 June 2011 (UTC)


 * Note that CD-ROMs use very good Error-correcting_codes, so that the information can be retrieved even after some data loss or corruption. I don't know whether the game is actually reading important data from the disc as you play, or if it just checks a few bits to make sure you have the disc (i.e. for copy protection purposes). If it's the former, then you are probably fine. SemanticMantis (talk) 20:36, 16 June 2011 (UTC)


 * Just to clarify, when you first install the game, there are several different installation options: "Compact install", "Typical install" (which is the option I have selected), "Full install", and "Custom install". Of these options, the "Full install" gives you the option to play without a CD-ROM in the drive, whereas the others require you to insert the CD-ROM every time you play.  So in those cases, I'm pretty sure it does read important data from the disc.  67.169.177.176 (talk) 00:32, 17 June 2011 (UTC)
 * I've just read the article on Reed-Solomon error correction (the error correcting code used on CDs), and it says that it can compensate for scratches/blemishes of up to 2.5mm in arc length along the path of the scanner beam. And since the scratches in my case are all very small and NOT coincident with the direction of scan (i.e. approximately straight-line rather than circular), I think the CD is OK.  (This also explains why that Reba McEntire CD I have -- which is practically covered in small straight-line scratches -- plays just fine, whereas another CD in my music collection -- which only has one small scratch, but in a circular direction -- always skips in one particular spot.)  Does anyone else have a dissenting opinion? 67.169.177.176 (talk) 01:00, 17 June 2011 (UTC)
 * Note that the amount of error protection on Audio CD is far less then on CD-ROM. Also most players will not attempt to reread a broken audio CD, instead if an error occurs during reading it will try to fix it with the error correction information and if this fails it will either play what it has or the smart players try to take the average between the last 2 good samples (i.e. interpolate what the bad sample should be) so if it's just a tiny error you don't get a sudden funny sound and the error won't generally be noticed. This compares with CD-ROM were generally most drives and OSes will attempt to re-read the CD-ROM if there is an error (which sometimes helps) and eventually will give up a spit an error to the user if the data can't be read correctly. I'm not sure but I believe the part you are reading is referring to CD-ROM. See which discusses the error correction situation primarily from an audio CD POV (it mentions there is significantly more error correction on a CD-ROM but say it's beyond the scope of the discussion). Nil Einne (talk) 07:22, 17 June 2011 (UTC)
 * Actually, the wiki article that talks about the error-correction codes doesn't mention whether the info applies to CD-ROMs or audio CDs. But since it consistently talks about two layers of protection, and the article CD-ROM mentions a third layer, I assume that it deals primarily with audio CDs.  So, it prob'ly stands to reason that the 2.5 mm figure applies to audio CDs, while CD-ROMs are even more damage-tolerant (just how much more, I don't really know and certainly don't want to find out for myself).  What is more important for me to know is, am I correct in concluding that a scratch in a concentric/tangential direction can be bad, but one in an approximately radial direction is usually no big deal (as my aforementioned experience with the radially-scratched Reba McEntire CD vs. the concentrically-scratched Patty Loveless CD seems to indicate)?  As I said, the FS2004 CD-ROM has many thin scratches, but only two of them are anywhere near tangential -- all the others are either radial or oblique. 67.169.177.176 (talk) 09:06, 17 June 2011 (UTC)
 * You may be right, at first I thought the article said the same applies to DVDs and Blurays which is not correct (as they are far closer to CD-ROMs, even the audio variety of DVDs) but reading more closely it doesn't say that. While a concentric scratch is obviously worse, my experience with many scratched discs is it's hard to predict whether a disc will remain readable. It also varies a lot from drive to drive. Although I should say from my experience with digital audio extraction the disc may play fine but reading the original data exactly is not always guaranteed. Plenty of discs don't have noticable errors but when read you find uncorrectable errors or can't consistently read the same data. Actually comparing the data usually shows the errors and sometimes if know where it is and listen carefully you can hear them. (Although I admit it's been a long time since I was in to DAE and drives have gotten better at that sort of thing over time).
 * Anyway for your original question, I would suggest you are approaching this the wrong way. As in all cases, if the data matters to you I strongly suggest you make a backup now rather then worrying about whether or not it will be readable in the future. Use something like ImgBurn or Isobuster to make an image of each disc and keep these on your HD. If you don't have the space, I suggest an upgrade since 2.3 GB or so shouldn't be a big deal nowadays. If it really, really matters to you, store copies somewhere else (whether burnt or images). I'm presuming of course you can legally make multiple backups of content you own where you live (or it's allowed in the EULA which I haven't checked).
 * Now FS 2004 does have Safedisc copy protection . Given how old it is, it's probably possible to back up that without much fuss (although it often depends on the drive particularly for CDs) but that's probably beyond the scope of RD/S and may also violate the DMCA in the US or similar legislation elsewhere. Also for such an old game, I'm quite sure the copy protection won't come in to play on installation so provide the disc with the copy protection info remains readable enough to be verified, you can always fully install the game from the backups then use the original but potentially not completely readable disc, to run the game.
 * P.S. If you find one or more of the CD-ROMs aren't readable without error then I guess your SOL and have the answer to your question. There are various solutions you can try to fix the scratches (e.g. brasso, toothpaste) you can find with a simple search. Snd I think DVD rental stores also have some sort of machine to polish the disc which should work fine on CDs and you may be able to convince the person to use on your disc. Although as I said earlier, I would try on different drives first. (I'm presuming you will try cleaning the disc before deciding it's unreadable.)
 * P.P.S. Worth remembering if you are regularly using the discs and aren't storing them in a temperature and humidity controlled environment you may get further errors in the future. In other words if the reflective layer starts to flake off or you scratch it, or your disc starts to get eaten by fungus, or it falls on the floor and you don't notice and step on it snapping it in half, or it develops some small cracks you put it in a high speed drive, knock the drive and it shatters; the scratches you're discussing now would be the least of your concerns. BTW only the last one i.e. disc shattering in drive is something I haven't personally encountered although I'm not sure whether the disc I had that snapped was stepped on or what.
 * Nil Einne (talk) 13:17, 17 June 2011 (UTC)
 * "Eaten by fungus"? "Don't notice and step on it"? Actually, while I use the discs regularly, I try to take good care of them (i.e. clean them regularly, handle them only by the edges, etc.). So the few damaged CDs I told you about are somewhat of an exception.  And as far as backups, I do have a backup copy on an external hard drive, so that's not a problem -- I was asking just in case of some worst-case scenario, like if both the main copy and backup copy somehow get corrupted.  And in fact, in the real worst-case scenario (i.e. both copies corrupted and the discs damaged beyond use) it's still possible to get a replacement copy on Abacuspub.com, but it would cost me more than when I first bought the game.  So there are quite a few options for me (and no, brasso is not one of them -- I've tried it once to repair a small concentric scratch in an audio CD, and ended up ruining the whole thing altogether). 67.169.177.176 (talk) 21:10, 17 June 2011 (UTC)
 * I've seen a consumer machine, which isn't that expensive, resurrect data CDs. It can be done but I wouldn't recommend using something ad hoc that isn't for this purpose. Wnt (talk) 23:35, 17 June 2011 (UTC)
 * I've used Brasso and toothpaste before with success. it depends on the nature of the scratch. I expect it's likely to work better on the CD-ROM because with an audio CD if you add more but smaller errors while removing a larger there's a good chance you'll make the situation worse particularly for playback (as opposed to DAE) whereas with CD-ROM you may make an uncorrectable error into a bunch of correctable ones (or a bunch of uncorrectable ones). Of course if the data is really important and it's your only copy and you're willing to pay for something better I wouldn't recommend it. But I would suggest it's definitely an option if the data isn't important enough to pay for better but you do want to try and recover it.
 * "Don't notice and step on it" may be avoidable if you take care (although accidents happen). But "eaten by fungus" is only likely to be avoidable by luck or storing the disc in a controlled environment. Storing it out of the sun may help but that's only really an issue for discs in cars. From my experience storing it in a jewel case all the time inside a drawer is no guarantee they won't be affected, not surprising it's not airtight after all. Having said that you appear to live in the US so I doubt it's an issue. The reports I've read have unsurprisingly suggested it only occurs in places with high humidity and temperature (although evidentally some from Germany ) and my discs were in Malaysia. It also doesn't seem that common since the number of reports isn't large. My experience is it looks like (which is also an example from the person who determined it was fungal growth) but from searching I found some reports of black dots.
 * P.S. I've never seen or heard of DVDs eaten by fungus. Since from experience (and the photos) it looks like the fungus are at least partially eating the metal layer it may not be easy for them to colonise DVDs.
 * Nil Einne (talk) 00:38, 18 June 2011 (UTC)
 * Thanks for all the tips. I think the CD is all right, but I'll check the data to make sure.  If the data is still good, I'll keep using it (with better precautions to avoid further damage); if not, then I'll replace it. 67.169.177.176 (talk) 05:49, 18 June 2011 (UTC)

Clear fluid where a scab is ripped off
Sometimes when a scab gets ripped off, the body secretes a clear fluid over the wounded area. What is this substance most likely? 20.137.18.50 (talk) 20:30, 16 June 2011 (UTC)
 * I think some kind of lymph or intercellular fluid. FWIW 67.169.177.176 (talk) 20:32, 16 June 2011 (UTC)
 * The general term for clearish fluids in the body is Serous fluid, and its literally all over the place. If it isn't inside of either cells OR your blood vessels, it is often called Interstitial fluid. The stuff you see when the scab is picked, which is clear, is just serous fluid.  If it is yellow and thick and has an odor, then it may be pus and you should see a doctor, because that is a sign of an infection.  Indeed, if there is any fluid coming out of your body which you cannot identify, you should see a doctor.  -- Jayron  32  20:48, 16 June 2011 (UTC)


 * Lymph.
 * μηδείς (talk) 02:07, 20 June 2011 (UTC)

Weatherproofing steel, black powder
Hi all,

I recently bought tubes of mild steel directly from a factory. The tubes are coated in some kind of black powder or oil. It makes your hands black when handling them, but doesn't come off the metal easily -- no handprints after handling or anything. Thanks! &mdash; Sam 166.186.171.172 (talk) 20:43, 16 June 2011 (UTC)
 * 1) What is this?
 * 2) If I want to weatherproof using RustOleum or something, should I remove it?
 * What you have is hot-rolled steel, or black steel - the black coating is mill scale, and will need to be removed before finishing. The alternative, cold-rolled steel or bright (mild) steel has been pickled in acid to remove the scale. Tevildo (talk) 01:03, 17 June 2011 (UTC)
 * In industry, they commonly use 6M HCl to remove mill scale. The stuff is very corrosive, though (which is the whole point of using it), as well as giving off irritating vapors, so chemical safety has to be strictly observed when handling it. 67.169.177.176 (talk) 01:22, 17 June 2011 (UTC)


 * Scale feels gritty. The description sound more like this is the lubricant that was applied for cold-drawing the tubes to final size. Yes, it must be removed before painting. Trichloroethylene or an acetone soaked cloth will wipe 'most' of this off (wear gloves and do it in a well ventilated area). Finish off by sponging them down with a bowl full of trisodium phosphate  solution (known as sugar soap in the UK and TSP in the US) to make sure they are thoroughly clean. Paint as soon as they are dry because the clean surface will immediately start to rust. You can get TSP from hardware stores and the like. --Aspro (talk) 12:19, 17 June 2011 (UTC)

Measure rainfall
Hello all. For the next month or so school is out and the summer classes don't start until mid-July so I'm going to be on vacation. I'm interested to know how much rain falls during the next three or so weeks, and instead of just looking it up on any reputable meteorological site I'd like to take my own measurements. However, I don't want to spend any money on this, so this should be using only the equipment of a well-stocked household. All my friends are going on vacation (or back home) too so I can't rely on anyone to come and take readings every day, which means I'll have to find some way to prevent or compensate for evaporation. I will also need to prevent wind from blowing the collecting thing over. How could I do this? thanks. 72.128.95.0 (talk) 20:50, 16 June 2011 (UTC)


 * You could cut a 2-liter bottle in two and flip the top-half upside down in the bottom half, forming a funnel. This would greatly lower loss through evaporation. You could easily weight the bottom with the addition of rocks. (That would increase the apparent waterlevel, but that's not an issue as you can always take the rocks out later or pour into a new container.) The wider your collector the more accurate this method will be. NB: I'm not sure if you're hoping to collect daily totals. This method would obviously not work for that. &mdash; Sam 166.186.171.173 (talk) 20:57, 16 June 2011 (UTC)
 * You collector should have the same surface area at the top as at the bottom, and be either cylindrical or rectangular in shape (that is, it shouldn't be measureably different sizes from top to bottom). A 2-liter soda bottle is approximately correct for this application (though you will get some error since the bottle narrows somewhat at the bottom).  What might work better is large coffee can with a properly sized funnel in the top, or something like that.  -- Jayron  32  21:15, 16 June 2011 (UTC)
 * Actually it works best if the opening of the funnel is much wider than the container because that magnifies the level making a high precision reading much easier. Dauto (talk) 03:46, 17 June 2011 (UTC)
 * The value of having a funnel with the same area as the cylinder is that 10mm of water in the cylinder means you have had 10mm of rain. Different sizes mean you will have to be a bit clever with your measuring scale. (You're right about precision though.) HiLo48 (talk) 04:19, 17 June 2011 (UTC)

Bioelectromagnetism Burn Marks


Microwaves and other radiofrequency radiations of the electromagnetic spectrum can have highly predictable effects on behavior at modest and even low levels of irradiation. 'D.R. JUSTESEN'

I bring this up as a rational possibility to my question, thinking possible cause is some unseen by the naked eye electrical current passing through the human body.

Question: What possible cause(s) for these burn holes on hologram stickers?

I'm on my 5th Power Balance bracelet. I send back for replacement after these burn marks get pretty large. The difference between these two picture examples, the center burn hole, I wore bracelet all the time. I was thinking maybe the shower could amplify electrofields, this is just speculation. Living on the penthouse of my downtown apartment; possible higher RF than on the 5th floor where I moved for the past 2 months (see current pic, with circular ring).

I read article on the RMIT University findings on Holographic technology wristbands. Bioelectric effects in regards to both bioaccumulation & environment could change outcome making RMIT case study ineffective. For what explanation would these burn holes be? I think many factors could be at play here. My brother wore these antistatic ankle straps when working on semiconductors to ground him as to not zap the materials he assembled. Enter the myth of Antaeus who derives his power from the earth, he loses his strength when feet not connected to the ground.

A few Questionables:
 * My clerical workplace has raised floor, I sit through traffic--disconnected to the earth, and my living space is also in the sky.
 * Could even the material the soles of our shoes be a factor in disconnecting the natural electrical current?
 * Could another factor be minerals in our water and foodstuffs? An example, I drank a very large bottle of Jermuk mineral water that I purchased from an Armenian market.  At break, went for a walk around the block and in the bright sunlight I felt these tinglys all over my body.  The SUN being that it is a very large magnet could charge these nanominerals in the body?
 * Maybe high RF from powerlines.
 * Maybe the 3 Cell towers directly above us at our workplace.
 * WIFI
 * Cell phone
 * Bluetooth
 * Monitors
 * Microwaves from home appliances

Note: these Power Balance holograms have no openings in silicon bracelet, the sticker being embedded in center of silicon. Thoughts anyone? --i am the kwisatz haderach (talk) 21:02, 16 June 2011 (UTC)


 * You are quite aware that these bracelets are part of a subset of knowledge known commonly as bullshit. -- Jayron  32  21:10, 16 June 2011 (UTC)


 * I was going to put it slightly more nicely: You are aware that the Power Balance article is listed in the category Pseudoscience? &mdash; Sam 66.31.201.89 (talk) 21:42, 16 June 2011 (UTC)
 * It's probably either bleached by exposure to light or by exposure to the natural acidity of your skin. As mentioned above, it's not worth spending money on that kind of nonsense. Dauto (talk) 21:59, 16 June 2011 (UTC)


 * I agree that the bracelet (and most of what you said) is total BS. As for the "scorch marks", they look more like some dye in the sticker got sweaty and ran, to me.  Or maybe it's the same scam as those foot pads that supposedly "remove toxins", but actually just turn black when exposed to moisture.  This seems to fool gullible people and make the scammers more money. StuRat (talk) 21:58, 16 June 2011 (UTC)


 * It may be oxidized iron; similar to the scam "Kinoki foot pads", which claimed to be removing toxins, and offered used pads covered in brownish-black substance as proof. This substance was simple iron oxide (rust); the pads contained fine iron powder or filings which oxidized when they contacted foot sweat. You may be interested that powerbalance, one of the main manufacturers of these bracelets, were forced to admit on their own website (since disabled for some reason; a summary is linked here) that they know their product does nothing; its effects are pure placebo power. - Running On Brains (talk) 22:25, 16 June 2011 (UTC)
 * Also, your comparison to Antistatic wrist straps is quite flawed; these work by creating a physical connection to the ground using a wire, to dissipate the buildup of static electricity that our bodies can occasionally accumulate when contacting various triboelectric materials. This charge buildup has absolutely no effect on human health, balance, or any sort of "holographic energy" (which is a made-up term by the way; there's no science behind it), aside from an unpleasant shock if you build a significant charge and touch a doorknob or something. The bracelets are not for health, but to avoid discharging onto sensitive computer components; even a weak current which will not harm a human can completely destroy some sensitive computer components. Antistatic straps which claim to work wirelessly do NOT work, and are a similar scam. - Running On Brains (talk) 22:31, 16 June 2011 (UTC)


 * Any microwaves or RF radiation that were powerful enough to make this happen would instantly destroy your cell-phone and any other electronic gizmo you happened to have on you. That sort of "scorching" damage would not be cumulative, you'd need a super-high dose all at once. (Any sort of closed metal loop would be worst of all. With that kind of microwave energy flowing around hoop earrings would pretty much set your ears on fire.) Unless you work in a giant microwave oven you can discount this possibility.


 * The simplest explanation is simple friction. Those diffraction grating holograms are an extraordinarily thin layer of metal over a paper or plastic backing. It doesn't take much to wear off the metal layer. Back when they used to put them on credit cards I would get similar black marks on my Master-Card hologram where the card rubbed against my wallet.  If I can rub a hologram black (Not the whole thing, just a line where it rubbed against the stitches in the leather card holder) in a year or so of taking my card out of my wallet about once a day, I have no doubt that you could wear down a hologram simply from your wrist movements. APL (talk) 02:13, 17 June 2011 (UTC)

Smart enough to write coherent question on Wikipedia, yet falls for this kind of garbage. Interesting. Zzubnik (talk) 08:22, 17 June 2011 (UTC)


 * You'd be surprised to know how many smart people fall for the dihydrogen monoxide hoax, among other things... 67.169.177.176 (talk) 09:10, 17 June 2011 (UTC)
 * Well the OP's previous questions suggests they have a unique perspective on many things. As 67 says there are plenty of smart people who fall for a variety of strange things which most relevent RS say are not supported by the evidence. Nil Einne (talk) 10:44, 17 June 2011 (UTC)


 * RS = Research/Scholarship ? StuRat (talk) 18:07, 17 June 2011 (UTC)
 * WP:RS. Reliable Sources. Tevildo (talk) 19:07, 17 June 2011 (UTC)


 * Yes. I'm thinking of things varying from holocaust denial, to AIDS denial, to the various vaccine controversies, to evolution rejection, to homeopathy, to climate change denial to whatever else many of which seem to attract some otherwise smart people. Nil Einne (talk) 01:15, 18 June 2011 (UTC)
 * Not to mention 9/11 conspiracy theories (arguably the most harmful kind of disinformation on this short list, with the possible exception of holocaust denial). And in fact, many of these bullshit theories not only attract many well-educated people, they actually attract a disproportionately large number of well-educated people compared to these theories' acceptance among the general population (i.e. a lot of college grads and PhD's, but not that many common workin' folks).  Which begs the question whether the so-called "education system", instead of imparting knowledge and the ability to reason, actually destroys people's common sense and the ability to tell the truth from falsehoods.  Here my own view is that the blame is on the current emphasis on "tolerance", "diversity", and "academic freedom", as well as all the different "alternative science" theories currently viewed as acceptable for teaching.  This will have to end and be replaced by teaching only those things that have gained scientific consensus, if we don't want our colleges to keep turning out thousands of lunatics. -- An American ultranationalist 67.169.177.176 (talk) 20:22, 18 June 2011 (UTC)


 * You need to be careful to distinguish between theories which have some scientific credibility, even if they aren't quite mainstream, like multiverse theory, as opposed to "theories" which contradict all scientific knowledge, like the universe, Earth, and humans all having been created in seven consecutive 24 hour periods. StuRat (talk) 23:24, 18 June 2011 (UTC)
 * I was meaning more along the lines of the "theory" that trees can concentrate cosmic energy, or that plants can understand human thoughts and speech. It's these kinds of bullshit theories that should be banned from the classroom, not the more credible ones like the multiverse theory. 67.169.177.176 (talk) 05:29, 19 June 2011 (UTC)


 * I don't want to take this too OT but would strongly disagree with that and in fact I excluded 9/11 conspiracy theories partly because particularly among the well educated it's not usually a big deal. This compares to the kids who got sick some of who died because their parents believe in nonsense about vaccines (and arguably other kids because of the herd effect). Or ditto for those who caused their kids or others to get worse or even die because of their beliefs about nonsense therapies like homeopathy. Or those who spread HIV because of nonsense about AIDS (although this tends to be a bigger problem among the uneducated). Or the plenty of people who undermine science education and advance by their nonsense about evolution. Or those who stop any attempts to deal with climate change not because they can't agree what the best course of action but because they refuse to accept the science.
 * There are a small number of people who try to take direct action against the US government because of their beliefs about 9/11 and the others may make problems in other areas but in reality the harm they cause to others by their wacky beliefs are usual minimal. One difficulty of course is a lot of these beliefs are somewhat interlinked, e.g. if you believe 9/11 conspiracy theories you're often more likely to believe nonsense about how vaccines are the government's attempts to control everyone (or whatever). One of the key problems with holocaust denial is of course that it usually ties in to anti-semitism and beliefs of 'Jews controlling the world' as well as damaging their ability to recognise the problems with racial prejudice and hatred.
 * Note I would also disagree with your views on proportionality. In fact among scientists in particular, most of those areas involving science have little acceptance. Many of them however have far greater acceptance among the uneducated. (AIDS denial, climate change and evolution would be obvious examples.) The dichotomy between experts+academics and the general public is a common feature of surveys and analysis. In the case of vaccines that's perhaps one example where there is great belief among the somewhat educated (but not scientists and the like) but that's partially related to difference in the trust of medical professionals and to be frank their parenting style and ability to 'research' such nonsense, many of the less educated simply haven't heard of the 'controversy'. There may be some truth when it comes to homeopathy but if you consider the wider field of alternative therapies including stuff like faith healing it probably isn't and this partially relates to things like target market, cost and subsidies (homeopathy tends to target the higher end market and also often isn't subsidised so a visit to the doctor may be cheaper).
 * Nil Einne (talk) 07:21, 20 June 2011 (UTC)
 * No, while evolution denialism is stupid and counterfactual, it does not directly harm anyone. Likewise, climate change denial has not (yet) been proved to cause harm, because there is at present NO consensus about the consequences of climate change (and therefore no clear case on whether any action should be taken to deal with it, or whether it should be allowed to continue); in fact, some studies I've seen indicate that the current patterns of climate change may actually BENEFIT agriculture in Europe and North America by increasing precipitation in mid-to-high latitudes.  AIDS denial and vaccine controversies are indeed very harmful and you are right in listing them, but AFAIK these are mostly a problem in the third world.  (And as you correctly pointed out, vaccine controversies in civilized countries are more likely to catch on among college grads and other "somewhat educated" folks -- especially those of them who are "environmentally conscious" -- rather than the uneducated.)  Holocaust denial is probably the most dangerous of these bullshit theories, because it promotes anti-Semitism that can lead to violence or even genocide; however, this is a theory that is equally popular regardless of educational background.  And 9/11 conspiracy theories ARE dangerous for a similar reason -- they promote anti-Americanism that ties into terrorism and subversion (as does your "no big deal" comment, as a matter of fact) -- which makes them MUCH more dangerous than evolution denial, or even climate change denial (but arguably not the other bullshit theories); and THAT is a theory that is MUCH more popular among the educated or "somewhat educated".  (Note to avoid ambiguity: for the purposes of this discussion, I've grouped the "somewhat educated" with the educated.) 67.169.177.176 (talk) 10:08, 20 June 2011 (UTC)

Insect species
Anyone can identify the insect? It flies in through the windows and with the body being about 1,5 cm long looks like a giant mosquito (any filemover may move the file to appropriate title).-- Brand meister t   21:10, 16 June 2011 (UTC)
 * We call these "skeeter hawks" or "skeeter eaters" but the less colloquial name is Crane fly. -- Jayron  32  21:16, 16 June 2011 (UTC)
 * They used to be called "Jinny Spinners" where I live. Has anyone else heard this name, or know where it comes from?    D b f i r s   07:18, 17 June 2011 (UTC)
 * I don't know, but maybe it comes from the spinning jenny? (Not that I can find any resemblance whatsoever between this moskeeter and the machine.) 67.169.177.176 (talk) 09:20, 17 June 2011 (UTC)
 * Might it be one of the Toxorhynchites, sometimes known as mosquito hawks? -- 110.49.240.35 (talk) 12:57, 17 June 2011 (UTC)


 * In some parts of the UK it's called a Daddy longlegs. It's not a mosquito and does not suck blood, but in larval stage (called leatherjackets) they cause untold damage to lawns. --TammyMoet (talk) 13:08, 17 June 2011 (UTC)

Plant Identification
Please help me identify this plant. I live in CT, US. Thank you

https://picasaweb.google.com/104361086395347992964/Camera?authkey=Gv1sRgCITXroezkfDSkQE#5618942795794284386

https://picasaweb.google.com/104361086395347992964/Camera?authkey=Gv1sRgCITXroezkfDSkQE#5618942857732649426

https://picasaweb.google.com/104361086395347992964/Camera?authkey=Gv1sRgCITXroezkfDSkQE#5618942900268313682

Barbaricslav (talk) 22:13, 16 June 2011 (UTC)


 * It looks like some sort of privet (ligustrum) to me, possibly ligustrum sinense. Richard Avery (talk) 06:10, 17 June 2011 (UTC)