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June 15

Measurement Unit Of Malleability

What is the measurement of malleability?Curb Chain (talk) 05:00, 15 June 2011 (UTC)

Malleability is the ability of a metal to be hammered into thin flat sheets, see the article Ductility. An example of a very malleable metal is gold. Malleability is an example of non-linear behaviour of a material that is stressed beyond its elastic limit (below which many materials obey a linear Hooke's law). There are approximate mathematical descriptions of material plasticity, see here, but I think there is no standard measurement unit and only empirical data on how materials behave beyond their yield point. Cuddlyable3 (talk) 11:14, 15 June 2011 (UTC)

From what I remember of material science, percent elongation at fracture is the best measurement of ductility/malleability. FWIW 67.169.177.176 (talk) 09:34, 17 June 2011 (UTC)

Putting Humpty Dumpty back together again

In various medical dramas, I've seen doctors do everything from move intestines aside to get at something to basically scooping them out of the abdominal cavity and move them aside. Granted, these are works of fiction, so I don't think that they're always very accurate. What I'm wondering though is on the other end of things. When the patient has been saved and all their organs need to go back into their body, how much care needs to be taken to make sure the intestines aren't knotted up or laying incorrectly or something. Is there a process or procedure to putting them back in? Dismas|^(talk) 06:19, 15 June 2011 (UTC)

My Dad had such a surgery, where his intestines were pulled out, then put back in, and they seemed to think they would just "find their way back" to the right spot. They didn't. From then on he was noticeably lopsided, with a bulge on one side of his abdomen. StuRat (talk) 07:07, 15 June 2011 (UTC)

I wonder if it was possible that your dad had a slight incisional hernia which weakened part of his abdominal wall and the pressure of the abdominal contents pushed out rather more on one side than the other, not uncommon in major abdominal surgery. Within the abdomen where the intestines are is a single cavity which would exert even pressure against the whole abdominal wall. I don't believe there is a right spot for removed and replaced intestines. The most important factors are that when they are replaced they should not have their blood supply compromised and the intestine should not be twisted, stretched or knotted in a way that peristalsis would not be able to correct. Richard Avery (talk) 14:39, 15 June 2011 (UTC)

The way the body packs the contents of the abdominal cavity can vary. An embryo is a different payload than the OP talks about, but its positioning is sometimes unlucky, see for example Breech birth and Umbilical cord prolapse. Cuddlyable3 (talk) 09:45, 15 June 2011 (UTC)

I think the answer is, "with great difficulty" - my sense is that with intestinal surgery, if the surgeons don't do everything just right (and maybe even if they do) necrosis of the bowel can occur. Wnt (talk) 00:35, 16 June 2011 (UTC)

Reminds me of a story I read somewhere (can't remember where, for the life of me) in which someone got his abdomen slashed with a dagger, and the surgeons were forced to remove the damaged part of his intestines because they couldn't repair the damage properly (and then they had to perform a second operation because he had developed peritonitis). 67.169.177.176 (talk) 05:39, 17 June 2011 (UTC)

I am a mechanical engineer now i need a notes for the following topics

Specific requirements for automotive lubricants – Oxidation deterioration and degradation of lubricants – Additives and additive mechanism – Synthetic lubricants – Classification of lubricating oils – Properties of lubricating oils – Tests on lubricants – Grease – Classification – Properties – Test used in grease. — Preceding unsigned comment added by Vigneshvig88 (talk • contribs) 09:38, 15 June 2011 (UTC)

Your list of subjects looks like a whole course in lubrication. A place to start is the article Lubricant and move on to Lubricant#Application by fluid types. There are a number of e-books on lubrication fundamentalsthat I have not read but that may be helpful. Cuddlyable3 (talk) 10:01, 15 June 2011 (UTC)

Our article on tribology (the science of friction and lubrication) may also be useful. Gandalf61 (talk) 10:53, 15 June 2011 (UTC)

Respondents: I've started a discussion of this question here. --Sean 19:56, 15 June 2011 (UTC)

Multiple biopsy

Do doctors perform biopsy on a cancer patient several times to discover how the cancer is developing? Or is it a one time shot? 2.139.12.164 (talk) 09:50, 15 June 2011 (UTC)

As with most questions like this one, it depends on the circumstances. There are some scenarios where several biopsies might be employed to assess for distant metastases of solid tumors, or serial bone marrow biopsies might be used to follow leukemia. --- Medical geneticist (talk) 10:18, 15 June 2011 (UTC)

Clearly more than one measurement at different times is needed to determine how anything is developing. Cuddlyable3 (talk) 11:17, 15 June 2011 (UTC)

True, but it need not be a biopsy, per se... often the cancer will be followed by less invasive imaging techniques such as positron emission tomography. Again, it is an "it depends" kind of answer. --- Medical geneticist (talk) 11:33, 15 June 2011 (UTC)

Medical geneticist's response is spot on; it really depends on the circumstances. For a specific example, a prostate biopsy will often be performed in the event of suspected prostate cancer. Because these tumors are often very slow-growing and the patients who develop them tend to be older, low-grade tumors – those with a low Gleason score – can sometimes be left in place untreated. The risk of disease progression during a period of watchful waiting may be less serious than the risk of negative side effects caused by more aggressive therapy. (Indeed, four out of five men over the age of 80 probably have prostate cancer. Most will never even know about it, because they'll die of something else long before the prostate cancer gets them.) If the patient's symptoms become more severe (or there are other signs of disease progression like an increasing PSA score) then another biopsy may be performed to determine if the cancer has become more aggressive. TenOfAllTrades(talk) 14:14, 15 June 2011 (UTC)

Light's behaviour

Why light travel in straight light? — Preceding unsigned comment added by Ahsanshkh (talk • contribs) 11:27, 15 June 2011 (UTC)

Because everything that is not deflected travels in a straight line. But even light does not always travel in a straight line. See lenses, prism and also gravitational lens. 5BYv8cUJ (talk) 11:34, 15 June 2011 (UTC)

Also relevent in this case is Geodesic (general relativity). One needs to define what it means to be a "straight line" before one can decide how and why light travels that way... --Jayron32 11:55, 15 June 2011 (UTC)

The Poynting vector is not a simple explanation why light, an electromagnetic radiation, travels in a straight line, but it serves to show how light's behaviour relates to its constituent electric and magnetic fields. Cuddlyable3 (talk) 13:09, 15 June 2011 (UTC)

See conservation of momentum. Light has a relativistic mass which depends on the energy carried by the photon (by E=mc²), which in turn is equal to the frequency in cycles per second times Planck's constant (or the frequency in radians times Planck's reduced constant... same thing). So light of a given frequency has a proportional amount of mass, traveling at the speed of light. (Hmmm, on second thought, that's a bit mind boggling - see Momentum#Momentum in electromagnetism and even Abraham-Minkowski controversy. You know once the name Minkowski comes up, you're not in Kansas any more ;)) This momentum doesn't change unless something acts on it. Wnt (talk) 00:42, 16 June 2011 (UTC)

Fundamentally, because of the homogeneity and isotropy of space. The laws of physics have to be such that light in a flat vacuum travels in a straight line, because there's nothing that would enable the light to "choose" a new direction to go in. It's a matter of symmetry. Red Act (talk) 02:57, 16 June 2011 (UTC)

That's right. And that accounts for the deflections and refractions implicit in the first response above. Whatever direction it's going in, it will continue to go in that direction until and unless some external force (such as a lens, prism, mirror, reflective surface, etc) makes it go in a different direction. -- Jack of Oz ^{[your turn]} 13:17, 16 June 2011 (UTC)

Neutrino oscillations and CP violation

"Neutrino particle 'flips to all flavours'" (BBC News) says that the T2K experiment has announced provisional results that indicate that muon neutrinos can transform into electron neutrinos, and hence the θ₁₃ component of the neutrino mixing matrix is non-zero. I follow all of that (after a hand-waving fashion). The article then goes on to say that this type of neutrino oscillation would be an example of CP violation. However, it doesn't really explain just how these particular neutrino oscillations violate CP symmetry. Can anyone explain the connection in more detail, please ? Gandalf61 (talk) 12:27, 15 June 2011 (UTC)

Neutrino mixing is governed by the Pontecorvo–Maki–Nakagawa–Sakata matrix. In principle, this involves 9 complex numbers. However, after requiring the total amplitudes to remain constant over time, assuming that all neutrinos always have the same chirality (which is true as far as we can tell), and assuming neutrinos are Dirac fermions (like all other known fermions, but the Majorana fermion model is not experimentally excluded), this reduces the 18 nominal degrees of freedom to only 4 real numbers. In particular, CP violation occurs if and only if the imaginary part of $sin(\theta _{13})e^{-i\delta }\neq 0$, where $\theta _{13}$ and $\delta$ are numbers to be determined experimentally. A non-zero imaginary part would imply that nuetrinos and antineutrinos have different mixing rates, or in other words, in a CP-inverted universe neutrino mixing rates wouldn't look the same (hence CP-violation). $\theta _{13}$ is known to be small, but the current report suggests it is non-zero. Incidentally, $\delta$ is also unknown and could be 0, so $\theta _{13}\neq 0$ is a necessary but not sufficient condition to show where neutrinos oscillations violate CP-symmetry. Dragons flight (talk) 20:13, 15 June 2011 (UTC)

(ec) A non-real entry in the mixing matrix violates the C part of CP, which is complex conjugation. The standard parametrization consists of three Euler angles (θ₁₂, θ₂₃, θ₁₃) and one complex phase (δ₁₃). This article is about a new constraint on θ₁₃. If you look at CKM matrix#"Standard" parameters you'll see that all of the terms with δ₁₃ in them also have a factor of sin θ₁₃. So, one could say that a nonzero value of θ₁₃ "opens up the possibility" of CP violation, since the matrix is real if θ₁₃ = 0 regardless of the value of δ₁₃. But it's a stupid thing to say because (1) this parametrization is arbitrary and (2) there was never any reason to expect any of these parameters to be zero, and it would be very strange if they were, so the possibility has always been open and the only interesting result, in that connection, would be one that "closed it off". It's basically the same as saying "we have determined that we are not standing precisely at the North Pole, which opens up the possibility that we are not standing precisely on the Greenwich Meridian." -- BenRG (talk) 20:21, 15 June 2011 (UTC)

Thanks for the excellent responses. So, if I understand this correctly, CP violation will occur if both θ₁₃ and δ₁₃ are non-zero, but the provisional T2K results only establishes one of these conditions. So what sort of experiment would be required to measure the value of δ₁₃ and/or to directly demonstrate CP violation in neutrino oscillations ? Are there any such experiments ongoing or at the planning stage ? Gandalf61 (talk)

δ₁₃ is much harder to measure, but proposals have been made. see for instance this paper. Dauto (talk) 16:39, 16 June 2011 (UTC)

Problems topping up mobile

Does anyone know what a 'Error Code-91 System Error' means ? Because i have tried to topup my mobile (T-mobile) at three different stores today and the same thing happened in each case, on the recepts was: 'Transaction Failed' 'Error Code-91' 'System Error' Does this mean my topup card, SIM card or both have been cancelled, which the staff in the stores believe it could be. Help!!!109.145.108.36 (talk) 12:41, 15 June 2011 (UTC)

It may help to note that the OP's IP is in the UK OK! OK! Enough abbreviations! so their mobile operator is T-Mobile (UK). Cuddlyable3 (talk) 12:56, 15 June 2011 (UTC)

Just doing a few obvious checks: have you taken the battery out and reseated it? Have you taken the SIM out and reseated it? Switched off and on again? --TammyMoet (talk) 14:49, 15 June 2011 (UTC)

Does T-mobile not have some sort of help line or email you can contact? Nil Einne (talk) 15:36, 15 June 2011 (UTC)

Try topping up your mobile via their website, or by text.--Shantavira|^{feed me} 16:13, 15 June 2011 (UTC)

I tried topping up again today and it worked first go. The system must have been down or some thing.109.145.108.36 (talk) 12:09, 16 June 2011 (UTC)

Horticulture Nurseries

What is a nursery? What types of nurseries are there? What are the opportunities and challenges of nurseries? — Preceding unsigned comment added by 62.24.111.249 (talk) 13:57, 15 June 2011 (UTC)

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. You may find the Wikipedia articles horticulture and plant nursery may help you, though your best option is to read through the text book that your teacher gave you and/or read the notes you wrote down during in-class lecture. --Jayron32 14:11, 15 June 2011 (UTC)

If the OP's homework was assigned not in a Biology class but in something related to Paediatrics or Pedagogy, then Nursery might be more relevant :-) . {The poster formerly known as 87.81.230.195} 90.197.66.241 (talk) 18:11, 15 June 2011 (UTC)

Directions near the Poles

Is there a standard way of giving direction at or near the North or South Pole? At lower latitudes, "the wind is from the south-west" means something.

But if someone set up a weather vane at the pole, how could they tell someone else which way the wind was blowing?

Thanks, Wanderer57 (talk) 15:01, 15 June 2011 (UTC)

If you want the smartass answer... if you're at the North Pole, the wind is always from the south. Otherwise, see this page. -Atmoz (talk) 16:56, 15 June 2011 (UTC)

The link that Atmoz provides says "By international agreement (WMO Manual on codes v. 1, Code Table 878), within one degree of the North Pole, the Greenwich (0 degree) meridian is used...i.e. within about 60 nautical miles of the North Pole, winds are reported according to a compass face, oriented so the "North" arrow points toward the 0 degree meridian, and in this restricted area, "North" no longer refers to the North pole, but to the observatory in Greenwich, England." That means nobody can say which way the wind blows at a spot in the Arctic 89°N 0°E. Cuddlyable3 (talk) 08:38, 16 June 2011 (UTC)

On first reading the NOAA page pointed out by Atmoz seemed to make sense. Rereading it, I'm not sure. It seems to imply that, when setting up a weather vane near the North Pole (an activity I hardly ever do but want to be prepared for), the north pointer should point toward the 0° meridian. But the 0° meridian is a line, not a point. What does it mean to point toward a line? Maybe I've got this all backwards. Please advise. Thank you. Wanderer57 (talk) 20:37, 16 June 2011 (UTC)

It is a line, but technically at the north pole, you are standing on the topmost point of that line, so the entire line is the same direction from you. Googlemeister (talk) 20:51, 16 June 2011 (UTC)

Thanks. That's fine if you are on the prime meridian, But suppose you are 1 kilometer west of it, just for example? Wanderer57 (talk) 21:49, 16 June 2011 (UTC)

You mean 1 km south right? West at the pole does not exists remember? Googlemeister (talk) 20:34, 17 June 2011 (UTC)

My interpretation is that they are only really talking about the pole itself, presumably with the assumption that the wind will be blowing in the same direction at any point within 1 degree of the pole. So, if the wind is blowing along the 0° meridian, then we say the wind is at 0°. If it's blowing along the 75° meridian, then it's at 75°. --Tango (talk) 22:02, 16 June 2011 (UTC)

Aside from the direction of the wind, the question applies to other directional information. Eg, if a treasure is buried 5000 feet from the camp in a particular direction, how to express that direction, aside from pointing. Maybe this is not a practical concern? Wanderer57 (talk) 04:26, 17 June 2011 (UTC)

Obviously in most situations, the people who would ever get there would know how to use specific coordinates to indicate the treasure's position. But if not, then I guess they would use the Greenwich observatory as their new "North" (or GW-North) and so say it is 5000 feet "GW-West". This is because you could apply this rule: "North" no longer refers to the North pole, but to the observatory in Greenwich, England. even if you are not exactly on the pole.--Lgriot (talk) 07:52, 17 June 2011 (UTC)

At the South Pole they often use a local Cartesian coordinates grid, centered at the pole and aligned so that "grid-North" at the pole corresponds to the is the Prime Meridian. That gives a well-defined sense of "grid-North", "grid-West", etc. for everywhere within the grid. If one extends the Cartesian system too far, one would eventually run into problems with the curvature of the Earth, but I've only ever seen it used within a few miles of Pole. At that level it is adequate for most purposes. Dragons flight (talk) 20:51, 17 June 2011 (UTC)

A southwesterly wind at the North Pole could mean that there is an incoming wind and low pressure positioned over the pole. ~AH1 ^(discuss!) 15:50, 18 June 2011 (UTC)

Nose to the Brain

Is there any truth to the idea of there being straight access from the nose to the brain or is that just a myth? — Preceding unsigned comment added by 71.143.240.229 (talk) 15:07, 15 June 2011 (UTC)

I don't know what you mean by "straight access", but consider the top diagrams at nasal cavity and human brain. The brain image also shows the nasal cavity, which appears to directly adjoin the brain at some points. SemanticMantis (talk) 15:34, 15 June 2011 (UTC)

What does "straight access" mean? direct unimpeded access? in that case, no. There is 1-2 mm layer of bone between the top of the nasal cavity and the base of the brain. Richard Avery (talk) 15:55, 15 June 2011 (UTC)

Is there also bone from the top of the ear to the brain, blocking access to the brain? — Preceding unsigned comment added by 70.136.157.251 (talk) 16:01, 15 June 2011 (UTC)

The olfactory receptor neurons connect to the olfactory nerve which connects to the olfactory bulb which connects to other parts of the brain via the olfactory tract - see olfactory system. Doesn't seem very much like "straight access" to me - not more so than the other sensory systems, anyway. Gandalf61 (talk) 16:11, 15 June 2011 (UTC)

How does cocaine get to the brain when sniffed if there is a bone between the nasal cavity and the base of the brain? — Preceding unsigned comment added by 70.136.157.251 (talk) 16:40, 15 June 2011 (UTC)

Thru the bloodstream. 67.169.177.176 (talk) 17:31, 15 June 2011 (UTC)

This one I know the answer to. For almost all of the classical sensory systems, the pathway from sensory organs to the cerebral cortex has a way-station in the thalamus. The olfactory system is the only one of the "five senses" for which signals can reach the cerebral cortex without passing through the thalamus -- olfactory receptors in the nasal epithelium project to the olfactory bulb, which projects to the olfactory cortex. Looie496 (talk) 18:19, 15 June 2011 (UTC)

"Straight access from the nose to the brain" might also refer to the danger triangle of the face. -- BenRG (talk) 18:53, 15 June 2011 (UTC)

I'm pretty sure the idea the OP is referring to is the one I described -- it is very commonly discussed in books or articles about the sense of smell. Looie496 (talk) 19:08, 15 June 2011 (UTC)

The sense of smell is so critical to the survival and brought such evolutionary advantage to early complex animals, that one could almost say that the brain is an extension of the olfactory bulbs rather than visa versa. http://www.sciencemag.org/content/332/6032/955 You can't get more direct than that. Later, part of this neural complex became light sensitive and became eyes. These developments happened independently in several different lifeforms. Someone may also be able to find reference to the sense of smell in humans, still over-riding all one's other senses. --Aspro (talk) 19:53, 15 June 2011 (UTC)

I think that's an exaggeration. Yes, mammals were little burrowing things that put a high priority on the sense of smell, but olfaction is just one sense of, say, fish. Go back far enough and you get to Cnidaria such as Cubomedusae, which have tiny organs which feature a surprisingly complex eye, a sort of ear (well, at least, a balance sensing organ), and an open vestibule for sense of smell. In bilateral animals I think the most general model you can apply is that the brain is a combination of ganglia in each segment (dorsal in vertebrates, ventral in arthropods, but homologous) which each have sensory and motor functions controlling the limbs and communicate up and down a nerve cord. I think the sensory organs are just features of primitive appendages (antennae, ear joints, stalked -> socketed eyes) with specialized sensory equipment leading to particularly massive processing centers in the brain. Wnt (talk) 06:31, 16 June 2011 (UTC)

No, Looie496 is right, see below. μηδείς (talk) 01:57, 20 June 2011 (UTC)

I tried looking into this before at Wikipedia:Reference desk/Archives/Science/2011 April 7#Blood-brain Barrier. There is some exchange between blood flow in the nose and the brain, but the "blood-brain barrier" should be behind that - separating the brain from the blood vessels themselves. Yet there was one reference about a compound having better access, and I wasn't really sure why. Wnt (talk) 00:04, 16 June 2011 (UTC)

This reminds me of how the ancient egyptians removed the brain during the mumification process. How they have to tap the device with a small hammer to gain access to the skull. Plasmic Physics (talk) 02:26, 16 June 2011 (UTC)

Responding to Wnt, blood doesn't really come into play. The olfactory epithelium contains receptor neurons that are directly exposed to air, so they are capable of absorbing certain chemicals from the inhaled air and transporting them via the olfactory nerves into the brain. Looie496 (talk) 23:04, 16 June 2011 (UTC)

You might also want to read up on Egyptian mummies and the procedures involving disposal of the brain, yet there is no such Wikipedia article. ~AH1 ^(discuss!) 15:48, 18 June 2011 (UTC)

Looie496 is quite correct, chemoreception is the oldest sense, common to all single celled organisms and all animals, including sperm which use it to find the egg. Olfaction is not a power that mammals or fish developed in preexisting nostrils, but rather the nose and related organs evolved around olfaction, and to say the brain in craniates is an outgrowth of the olfactory lobe at its nexus with the locomotory nervous system is entirely justified ontogenetically. Light sensitivity is common to all animals, but the evolution of vision and eyes, rather than the ability to sense the direction of light and the day-night cycle is something that comes ages later than chemoreception. Neither lancelets nor tunicates possess eyes, but they do process chemoreceptive signals in what amount to their heads (at least while they have them). 01:57, 20 June 2011 (UTC)

spin current

An electrical current is generally unpolarized (consisting of 50% spin-up and 50% spin-down electrons); a spin polarized current is one with more electrons of either spin. By passing a current through a thick magnetic layer, one can produce a spin-polarized current. http://en.wikipedia.org/wiki/Spin_transfer

how come current is composed of half spin up and half spin down? is spin up magnetic north and spin down magnetic south? (apparently this is true is it correct Spin "up" would mean the electron is acting like a bar magnet whose north pole is pointing up; spin "down," the opposite.) — Preceding unsigned comment added by 82.38.96.241 (talk) 21:09, 15 June 2011 (UTC)

To be precise, half of them have the vertical component of the spin up while the other half has that component pointing down. The horizontal component being unknowable (which is not the same as unknown). Imporntant note: We talk about spin up and down by convention but we could just as well talk about spin left and spin right, or spin forward and spin backward if so we wished. Dauto (talk) 21:19, 15 June 2011 (UTC)

Personally, I prefer inside and outside. Plasmic Physics (talk) 00:28, 16 June 2011 (UTC)

so is there only really 2 directions of spin and they happen to provide the effect for the north and south magnet — Preceding unsigned comment added by 82.38.96.241 (talk) 21:22, 15 June 2011 (UTC)

It is more understandable to say that for unpolarized electrons the spin points in a random direction in space; however, the nature of quantum mechanics is that we can only ever measure one component of it's direction per electron. So we pick an axis in space (call it vertical), and see how many of them have a positive vertical component (up spin) and how many have a negative vertical component (down spin). Another aspect of quantum mechanics is that we can only really get positive or negative (not a magnitude). If you have a consistently polarized spin current you can get more information about the spin orientation by measuring many electrons, but you are strongly limited about the information that can get from any single electron because the act of measuring it changes it. Dragons flight (talk) 22:03, 15 June 2011 (UTC)

(EC) It's not really that there are only two directions of spin. Rather, it's a matter of no matter which direction you arbitrarily choose, if you measure the spin of an electron along that direction, there are only two possible values that the spin can be measured to be. So if you measure the spin along the z direction, for example, the spin will either be in the +z direction or the -z direction (the magnitude of the spin will be the same either way). The amount of spin in each of the x, y and z directions are not independent; after you measure the spin along one axis, you can't know anything about what the spin is along the other two axes. The measurement process basically messes up the spin along any orthogonal direction. For example, if you measure the spin in the z direction and it's in the +z direction, and then measure the spin in the x direction, and then measure the spin in the z direction again, it's a 50/50 chance as to whether the spin will be measured to be in the +z or -z direction in that final measurement. Red Act (talk) 22:08, 15 June 2011 (UTC)

Also worth pointing out that earth's magnetic field are believed to be produced by electric currents in its liquid core as opposed to electron's magnetism. Dauto (talk) 00:09, 16 June 2011 (UTC)

ADHD Medication Rankings

This question was removed [1]. I have restored it, because the remover was wrong, and it does not violate any of our medical advice guidelines. Note that I have not restored one response, as it may have violated our guidelines. See also the discussion on the talk page. Buddy431 (talk) 00:44, 16 June 2011 (UTC)

I can specifically find all of the ADHD medication and dosages. I can not find which one is stronger than the other. Like Adderall XR is the slow relsease, but is Vyvanse more powerful? Adding a section to list ADHD medications ranking them from the smallest (such as Adderall) to a more powerful or longer lasting medication (such as Concerta and Adderall XR) would be very helpful in my opinion. Thank you for any knowledge on this subject. — Preceding unsigned comment added by IT Zach P (talk • contribs) 21:55, 15 June 2011 (UTC)

I think discussion on the talk page favors retention of the question; in any case, in general it is not so simple to answer. While it can seem easy to say that one chemical is more potent than another, it's not like comparing 9 to 10. The dosage for either drug can be adjusted up or down. The affinity constant, bioavailability, and pharmacokinetics can differ in different ways. One compound might be a complete agonist or antagonist, while another has some mixture of these activities. One compound might be more potent, but have more serious side effects. To give a simple example, everyone knows that "heroin is more potent than morphine" - yet when a soldier has had a piece blown off on the battlefield, he still receives morphine, because it's the most potent all-around painkiller. You can evaluate which drug is "most potent" in that sense - what you would use to get the job done in a certain situation - and in general this is the basis of medical diagnosis and prescription. But the fact that all these drugs are still out on the market is a sign that there may no hard evidence to say which one is best for all people. Wnt (talk) 00:17, 16 June 2011 (UTC)

Monkey from Antalya, Turkey?

Sorry, if this is not the best place to ask this question. Can anyone tell me what kind of monkey this is? --Phagopsych (talk) 22:00, 15 June 2011 (UTC)

Maybe a Spider monkey? (Just a guess.) Bus stop (talk) 22:08, 15 June 2011 (UTC)

I think it's a vervet monkey, but there are a number of species that look pretty similar. Looie496 (talk) 23:07, 15 June 2011 (UTC)

...or maybe a grivet, which is very closely related to a vervet. Looie496 (talk) 23:17, 15 June 2011 (UTC)

Incidentally, this is exactly the right place to ask this question. StuRat (talk) 08:35, 16 June 2011 (UTC)

Thanks a lot. In the pic doesn't show very well but it has none or very little hair on the top of head (you know, that darker grey bit). Also it had a very long tail, like the Vervet monkey, but the head looks more like the grivet's. Lovely animal, by the way. Very friendly. I know they should not be kept as pets but it was really playful and affectionate, jumping to people's arms without much of a prompt :-) --Phagopsych (talk) 19:12, 16 June 2011 (UTC)

Yes, this is obviously a green monkey, but none of the various species is native to Turkey. μηδείς (talk) 01:58, 20 June 2011 (UTC)

Why no CO2 clouds high in the atmosphere?

Phase plot for carbon dioxide

Why doesn't CO2 condense into clouds where the temperature is low enough? Count Iblis (talk) 23:30, 15 June 2011 (UTC)

The minimum temperature in the atmosphere occurs at the base of the ionosphere, and is usually in the 250-300 Kelvin range. As you can see from the plot I have attached, CO2 does not have a stable solid phase in that temperature range at low pressures. Looie496 (talk) 23:49, 15 June 2011 (UTC)

There has been much speculation that polar mesospheric clouds, sometimes known as noctilucent clouds, are seeded by carbon dioxide crystals. Mesospheric clouds on other planets, especially Mars, have been observed to contain mostly carbon-dioxide ice. Other planets, like Jupiter and Neptune, also have mesospheres (of a sort); clouds in these planets can contain carbon dioxide, ammonia, and especially methane ice. Nimur (talk) 02:52, 16 June 2011 (UTC)

The difference is, the mesospheric temperatures on all those planets are much colder than on Earth. 67.169.177.176 (talk) 08:39, 16 June 2011 (UTC)

More importantly, the pressures of those planets are much higher than similar temperatured regions on earth. Phase is a function of both pressure and temperature; on Earth the coldest part of the atmosphere is of a pressure which is far to low to allow carbon dioxide to condense into crystals. On larger planets, like Juptier and Neptune, the lower levels of insolation means lower temperatures, while the greater mass means greater gravity, and thus greater atmospheric pressures. The OP appears to be considering only the temperature when questioning if CO2 should condense in the upper atmosphere of Earth. --Jayron32 12:15, 16 June 2011 (UTC)

Isn't it partial pressure, not pressure, that matters? High pressure doesn't necessarily mean high partial pressure. --Tango (talk) 12:34, 16 June 2011 (UTC)

Indeed, but there is no where on Earth where even the total pressure of the atmosphere exceeds the minimum pressure required to have CO2 condense. Logic would seem to dictate that a gas which makes up a fraction of that total cannot exceed the total itself, so rather self-evidently there is nowhere on Earth where CO2 should spontaneously condense. --Jayron32 15:26, 16 June 2011 (UTC)

I see, I forgot about the pressure :) . Count Iblis (talk) 17:01, 16 June 2011 (UTC)

Note that the graph at right only goes down to 200K however...at lower temperatures CO₂ will sublimate at Earth-like pressures and even lower; Mars has a surface pressure of around 10% of Earth's at most, and they have a large cap of CO₂ ice at each pole, as well as carbon dioxide clouds at several different layers of the atmosphere.-RunningOnBrains^(talk) 17:04, 16 June 2011 (UTC)

Sure, but below 200K isn't Earth-like temperatures (at any altitude), so what happens at Earth-like pressures at those temperatures isn't particularly interesting. --Tango (talk) 18:00, 16 June 2011 (UTC)

The mesosphere article says: "The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally-occurring place on Earth with temperatures below 130 K." Count Iblis (talk) 19:51, 16 June 2011 (UTC)

Some places in Antarctica (e.g. the Vostok station) can get below 200 K in the winter. 67.169.177.176 (talk) 20:17, 16 June 2011 (UTC)

And as far as the mesosphere is concerned, note that the partial pressure of CO2 is many times lower than at sea level, which further hinders condensation. Also, at such high altitudes it's possible to start getting some UV-induced dissociation of CO2 into O1 (atomic oxygen) and CO -- which would further reduce the partial pressure. FWIW 67.169.177.176 (talk) 20:38, 16 June 2011 (UTC)

At levels of the lower stratosphere, temperatures and pressures are often low enough for water vapor and sometimes even carbon dioxide to freeze out of the atmosphere and reduce the greenhouse effect at those levels, especially considering that the greenhouse effect actually cools the stratosphere. See physical effects of climate change#Upper atmosphere. ~AH1 ^(discuss!) 15:43, 18 June 2011 (UTC)

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)

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. Dbfirs 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 K_sp 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

--Jayron32 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#Biopsychological_theories has a little bit as well. Most of what we call "personality" seems to have its origins in the Prefrontal cortex and the Amygdala. --Jayron32 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". --Jayron32 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. — 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#Adaptedness_and_fitness 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.-RunningOnBrains^(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. -RunningOnBrains^(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. -RunningOnBrains^(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 [2] 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 [3]. 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 [4]) 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 [5] (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. --Jayron32 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.

1. What is this?
2. If I want to weatherproof using RustOleum or something, should I remove it?

Thanks! — Sam 166.186.171.172 (talk) 20:43, 16 June 2011 (UTC)

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. — 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. --Jayron32 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

Last bracelet returned

Currently worn bracelet

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. --Jayron32 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? — 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. -RunningOnBrains^(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. -RunningOnBrains^(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

Name me!

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).--Brandmeister t 21:10, 16 June 2011 (UTC)

We call these "skeeter hawks" or "skeeter eaters" but the less colloquial name is Crane fly. --Jayron32 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? Dbfirs 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)

June 17

Average weight for Americans and Europeans

Where can I find the average weight for (adult) American men & women and European men & women? --CGPGrey (talk) 12:28, 17 June 2011 (UTC)

A search for 'average weight american' easily finds [6]. My guess even before searching is trying to find an average weight for Europeans is unlikely to be easy and a search for 'average weight European'. I would suggest you compare different European countries. If you really want an average for 'European' you should at least definite the term. Do you mean all EU countries only? Nil Einne (talk) 12:43, 17 June 2011 (UTC)

The WHO keeps a lot of health facts for countries throughout the world here. For weight, I believe they only report the percent that are obese instead of actual weight. You can go into the data repository to get actual weight values. The result will be a bit useless. For example, I only have around 2 million patients in the data set I'm using right now and the average weight is 84+-27kg. That is a HUGE variance and it give no information about the distribution. -- kainaw™ 12:49, 17 June 2011 (UTC)

Obesity is usually determined by body mass index which has numerous criticisms (see the article) but is far better then weight alone. You can find average BMIs for various European countries fairly easily. E.g. [7]. However the OP is apparently interested in weight Nil Einne (talk) 13:41, 17 June 2011 (UTC)

This BBC article has figures for America and Britain (wouldn't be such a bad call for Europe, depends how far east you include) that they believe are comparable. Grandiose (me, talk, contribs) 13:15, 17 June 2011 (UTC)

I'm not convinced the UK is a good choice to represent Europe since various sources say the UK is one of the highest in Europe [8] [9] for females. Notably France is on the lower end of the scale (not sure about Germany, I guess it's in the middle since usually not mentioned.) That's for BMI not weight but still seems a bad choice if you want an average European figure. Nil Einne (talk) 13:41, 17 June 2011 (UTC) Edit: [10] is the study mentioned in the Daily Mail article. It has a lot of data on the BMI of different countries including for Western Europe (as they define it) although is primarily analysing the change rather then just the current figures. 14:05, 17 June 2011 (UTC)

(e/c, not significantly.) Well, another article suggested French women - the thinnest - were about 9st11. The BBC article says British 10st3-and-a-half. So perhaps we can refine the average figure to only a little under the British one, perhaps 10st. Depends how accurate the OP needs. That would be around 1st lighter than America (this article actually gives a somewhat higher figure than 11st, 11st10lbs. Grandiose (me, talk, contribs) 14:09, 17 June 2011 (UTC)

Well the Telegraph article gives 70.6kg UK women for 2008 (well the Lancet figures seem to be from then). Having said that is also gives 63.5kg for 1980 and I doubt it went from 63.5 to 65 kg in 2001/2002 (BBC article is 2004 but [11] suggests the data is from then) then to 70.6 kg in 2008 suggesting these figures aren't from really comparable.

The difference in BMI from the Lancet article (in 2008 26.9 for the UK, 24.8 for France) definitely suggests a bigger difference although we don't know if the average height is the same (but the average height in the Telegraph article and the article on French women's weight is the same, although that article is from 2006). This meanwhile gives 66.7kg for UK women [12] in 2006. I notice some sources are using a BMI of 26.2 for UK women but the Lancet gives this as the 2000 figure (for comparison the French were 24.7 in 2000).

BTW if the OP does want to use BMIs, the 2000 figure for US men is 27.7, 2008 is 28.5; 2000 US women is 27.5, 2008 28.3. For UK men 2000 is 26.6, 2008 is 27.4. For French men 2000 is 25.4, 2008 is 25.9. These figures are all taken from the Lancet megareview so are intended to be comparable.

P.S. The average weight for US is 71 kg in the BBC article (the time frame is unclear [13] but let's take it as 2001/2002) vs 74.7 kg by the CDC (which appears to be using 2006 figures). In other words, it may be fair to compare the Size figures since they come from a comparable data source but comparing those to other figures is probably not a good idea. In terms of the UK average as a European average, since the data is fairly old it's not quite as bad (since UK women seem to be increasing faster then the French at least) although it's possible/likely? the average weight for French women would be lower then the figures from the above article if comparable SizeFrance figures were used.

Nil Einne (talk) 22:30, 17 June 2011 (UTC)

I believe this is from the same Lancet survey and fun to look at.[14] --JGGardiner (talk) 06:11, 18 June 2011 (UTC)

Figures for the US from old data must be corrected for inflation:

Americans are not just getting fatter, they are ballooning to extremely obese proportions at an alarming rate.

Count Iblis (talk) 15:00, 17 June 2011 (UTC)

• BMI at least factors in height. It would be silly to compare the weight of tall and short people without factoring in height, and conclude a taller population was fatter just because they weighed more. Americans seem to be bimodal. I see some children and young adults who sit and eat and plump up. If their Mom tells them to "Go play," they sit in front of a video game with a supply of snacks. Others run all the time, go to health clubs, ride bicycles, participate in competitive sports like soccer or swimming, and stay quite thin and well muscled. I suppose if there were a major conventional war, the lard-butts could be drafted to remotely fly combat drones using their well-honed joystick skills. Edison (talk) 15:19, 17 June 2011 (UTC)

• ...and the healthy ones would be drafted and sent to front line infantry positions. Hmmm, pass the Cheesy Poofs please. StuRat (talk) 18:05, 17 June 2011 (UTC)

You might be interested in Drop Bears.5BYv8cUJ (talk) 11:01, 18 June 2011 (UTC)

• That's supposedly what happened to the French. I used to hear that the Napoleonic Wars shortened the height of the average Frenchman by several inches. (I guess DeGaulle's ancestors were 4-Fs). ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:33, 17 June 2011 (UTC)

I don't think we should make any assumptions here. There is convincing evidence that adenoviruses are involved - for all we know, obesity is the outcome of some kind of Cold War battle. There's also epigenetics to consider, which involves some truly fearsome risks that people really haven't considered at all. If the effects of the easy life are passed on from parent to child, accumulating as methylations or chromatin changes, there's truly a chance that we get to a point in a few generations where children are metabolically prone to unlimited weight gain. Likewise, we might find over the course of a few decades that some unknown factor added to our environment has led 90% of newborns to be autistic. Stuff like this could happen, and if it does is almost impossible to predict it, figure out why, or stop it. Wnt (talk) 23:32, 17 June 2011 (UTC)

So the Soviet Union won after all? Nil Einne (talk) 01:07, 18 June 2011 (UTC)

Bawris

What are Bawris?Why are these being recieved due to peoples participation? — Preceding unsigned comment added by Rudraksh Parey (talk • contribs) 14:21, 17 June 2011 (UTC)

I take it you're not referring to Stepwell? Nil Einne (talk) 14:31, 17 June 2011 (UTC)

Seriously, I searched really hard, but I have no idea what you are asking, Rudraksh. Can you attempt to re-phrase your question?-RunningOnBrains^(talk) 18:27, 18 June 2011 (UTC)

Small photography

I am interested in taking photographs of relatively small things. Not electron microscope stuff, but I would love to be able to, for example, take a clear photograph of a single poppy seed at the level so that it took up most of the frame. Can anyone give me a short explanation of the equipment I would need? and any tips? I know this is not very properly a science question, though it is somewhat in the bailiwick, and the miscellaneous desk is in read-only mode (there's a note to that effect when you try to post there). Thanks.--108.14.194.26 (talk) 15:26, 17 June 2011 (UTC)

The article on Macro photography might provide some guidance, but you would need a powerful lens to photograph a single poppy seed full-frame. I haven't tried this level of magnification, so await some experts to give tips. Dbfirs 15:38, 17 June 2011 (UTC)

The most critical piece of equipment for macro photography is a macro lens. This is a lens with a short minimum focusing distance; it usually also has a large aperture and short focal length. Most macro photography guides and tutorials also recommend a very large lens aperture so that you can collect a large amount of light in a short time and control your depth of field. Many macro lenses also have a short focal length (because this helps frame close subjects and makes it easier to design a short minimum-focus-distance. On top of this, you may want some "whisker" flash equipment for off-center illumination. Here's an example of a full kit, the Nikon SB-R1 "Close-Up Flash" system. If you have a large budget, a full-frame sensor can make a big difference; the optics are much more expensive, but this allows the optics to resolve a more sharp image, which makes a big difference when you are shooting a very close-up object.

You don't require any of this for macro-photography; in fact, modern mobile-phone cameras and point-and-shoot cameras usually have wide-angle lenses with ridiculously short close focal distances. (This is an "added bonus" due to their compact size). But, you can control image quality, lighting, noise, and other photographic and optical parameters much more closely when you switch to a DSLR camera.

Personally, I do not shoot much macro-photography, but when I do, I use the (very unconventional) 70-300mm lens on my Nikon D90. My close focal point is about 2 meters away, so it does not appear to be macro-photography; but with the DX crop-factor and 300mm focal length, I actually produce a larger "magnification" (pixels per mm of subject, or "reproduction ratio") than most of the macro-lenses I have compared. I should also say, the Nikon 60mm "Micro" produces incredibly sharp pictures at close focus; but I don't want to spend 600 dollars on what I consider a "single-purpose" piece of equipment.

Here's a great tutorial on macro photography equipment and technique from Ken Rockwell. And, here's an official tutorial from Nikon, Minimum focus distance. Nimur (talk) 16:25, 17 June 2011 (UTC)

"Single poppy seed full frame" is somewhat out of the range of macro photography, and more in the range of microscope photography. While typical micrographs are usually thought of at the 400x/single-cell level, you can also do ~10-40x photography, e.g. with a dissecting microscope. I haven't done any photography with them, but I have used dissecting scopes to examine small object, and you can get good detail without having to do any special preparation. A decent dissecting scope with a camera mount shouldn't be all that more expensive than a decent DSLR macro lens. (P.S. The Refdesk randomly being read-only for IP users is a known issue - usually it can be resolved simply by refreshing the page in your browser.) -- 140.142.20.229 (talk) 16:50, 17 June 2011 (UTC)

There's a difference between "full-frame" and "full-frame." In common parlance, full frame means "takes up the entire area of the picture," which is a very useless term - because you can crop any photo so that the subject fully fills the entire crop area. "Full frame" in photographic jargon means "projects an optical image whose size is equivalent to that projected onto 35-mm film." This is a much more specific description - it tells you how much optical zoom you have provided; if a poppy-seed fills a full-frame camera, you can calculate the magnification ratio at any given subject distance, and therefore pick the lens focal length you need to do it. (For example, here's a free online calculator). And, as seen here, a poppy seed shot through a 50mm macro lense will nearly fill APS-C - no microscope required! A longer focal length lens will fill full-frame, but you'll have to use every trick in the book to focus (and brightly illuminate) the poppy seed. Nimur (talk) 17:51, 17 June 2011 (UTC)

I second the suggestion for using a microscope with a camera. One potential problem is the vibration created by hitting the shutter button, which can ruin the photo. This could be handled with a timer that allows time enough for the vibration to settle, or with a remote trigger (wired or wireless). StuRat (talk) 17:59, 17 June 2011 (UTC)

Thanks for all the information, everyone. I have printed this out and will check out the external sources and links at my leisure!--108.14.194.26 (talk) 21:49, 17 June 2011 (UTC)

As for getting really close, as you said, there are a couple of options. This lens can shoot extremely close (but comes only for Canon mounts). You can also try a macro lens that has a relatively long focal length, such as this or this, and then using close-up filters and tele-extenders to get even closer. And then you can try to make a beast like this or this, with a reverse lens attached to a macro lens. And you can always attach a camera to microscope too. --T H F S W (T · C · E) 05:08, 18 June 2011 (UTC)

A good photo of sesame and poppy seeds. See the article Poppy seed. Cuddlyable3 (talk) 14:25, 18 June 2011 (UTC)

Does a Encyclopedia Naziana exist?

Does a Encyclopedia Naziana exist?Smallman12q (talk) 16:02, 17 June 2011 (UTC)

Not according to Google. Red Act (talk) 16:36, 17 June 2011 (UTC)

Yes and we can be sure that there exists one where Smallman12q is editing :) Count Iblis (talk) 18:29, 17 June 2011 (UTC)

To provide a serious answer (as others might be reading this, you know), a four-volume condensed edition of Brockhaus, which contained a considerable amount of information on contemporary German life, was published in 1938 - see [15]. It only merits a passing mention in our article on the encyclopaedia - why, I won't speculate. Tevildo (talk) 19:05, 17 June 2011 (UTC)

Big bang?

Is an expansion of the Universe starting from a point in the "Big Bang" the only explanation of the red shift observed by astronomers? — Preceding unsigned comment added by 84.209.86.125 (talk) 19:19, 17 June 2011 (UTC)

No. In particular Hoyle's Steady State theory was proposed to explain the observed red shift. But other evidence rejects the SST, in particular the cosmic microwave background radiation. BBT (or really the set of very similar "universe was once exceedingly small" theories we might collectively call the BBT) also explains the relative preponderance of elements very nicely. -- Finlay McWalter ☻ Talk 19:29, 17 June 2011 (UTC)

There is also the tired light theory which has also pretty much been ruled out. Dauto (talk) 20:02, 17 June 2011 (UTC)

Incidentally, if you're interested in this kind of thing, I can recommend Simon Singh's book Big Bang: The most important scientific discovery of all time and why you need to know about it. Despite its title, the book is mostly about the evolution of cosmological ideas and the weighing up of evidence that forced paradigm shifts (gosh that sounds boring); it's about why smart people believed wrong things and how new evidence made for better knowing (that sounds better). -- Finlay McWalter ☻ Talk 20:12, 17 June 2011 (UTC)

You could come up with alternate explanations, but Occum's Razor comes into play, and thus the simplest theory to explain why everything seems to be moving away from a single point is that it is. StuRat (talk) 23:13, 17 June 2011 (UTC)

But any theory is simpler than decompression with a bang of everything from a mathematically singular, physically impossible, MAGICAL MYSTICAL point. Some have thought that dubbing the theory after it was hypothesized "Big Bang" was meant to ridicule its unlikeliness. It is also unfalsifiable. Cuddlyable3 (talk) 12:38, 18 June 2011 (UTC)

It's not unfalsifiable; there are many predictions based on the Big Bang theory which can be proven true or false. The reason the theory became so prominent is due to one of these predictions: the Cosmic background radiation. Physicists predicted it should exist, and two radio technicians who didn't even know about this prediction found it. I'd say that's almost the opposite of unfalsifiable.-RunningOnBrains^(talk) 18:31, 18 June 2011 (UTC)

Of course, there are many hypotheses on what started the big bang: brane theory, the big crunch of another universe or a scientific experiment by higher-dimensional beings, for example. See also non-standard cosmology. ~AH1 ^(discuss!) 15:19, 18 June 2011 (UTC)

Big bang cosmology is about the evolution of the universe from an early hot, dense, uniform state of (as yet) unknown origin. It is not about a bang, or a singular point. -- BenRG (talk) 21:31, 18 June 2011 (UTC)

Fixing nesting box on to tree trunk

I've got a wooden nesting box, without any bracket or screw holes. What is the best way to fix it to a tree trunk of about one foot or so diameter? 92.24.136.31 (talk) 21:14, 17 June 2011 (UTC)

The RSPB has a page of info about nest boxes here, which says "Fixing your nestbox with nails may damage the tree. It is better to attach it either with a nylon bolt or with wire around the trunk or branch. Use a piece of hose or section of car tyre around the wire to prevent damage to the tree." It also has advice about locations for the box, which varies depending on the species of bird you're accommodating. -- Finlay McWalter ☻ Talk 21:30, 17 June 2011 (UTC)

Perhaps bungee cords would work, provided you can find a place to attach the hooks to the box (you may need to drill holes). The flexibility they provide would allow for tree growth. You'd also want to put the box above where a branch leaves the trunk, so the weight of the box is supported by the branch. StuRat (talk) 23:03, 17 June 2011 (UTC)

And please make sure it is in shade or faces north, otherwise the chicks can roast to death on a sunny day. If you live in the northern hemisphere there is not much point in putting it up before next year.--Shantavira|^{feed me} 10:41, 18 June 2011 (UTC)

Detection of light at great distance

Hi. Suppose I have an automatic gun on a rotating turntable, firing ten rounds a second or something. If I stand some distance away, then (ignoring all "indirect" evidence like sound and sight) I can only detect that the gun is firing if I happen to be standing in the right place so that a bullet actually hits me. On the other hand, if someone drops a rock into the middle of a pond then I can, in principle, detect the ripples anywhere on the perimeter of the pond at any distance.

OK, so now suppose I sweep a torch across the heavens. Would anyone along that path, say in a distant galaxy, be able in principle to detect the torch, like the waves in the pond? Or would only those lucky people hit by a photon be able to detect it, like the turntable gun? If the latter, then "what happened to the light waves in the gaps"? 86.160.209.60 (talk) 22:00, 17 June 2011 (UTC)

I believe light behaves like a particle in this instance. That is, the distant planet would have to be lucky for one of the photons from your flashlight to reach it. We have dim objects in space that our best telescopes can only detect as an occasional photon, but a computer (or previously long exposure film) can eventually form an image out of those individual photons. As for why light is sometimes a particle and sometimes a wave, or how you can predict which it will be at an given moment, I'm clueless there, and I don't think I'm the only one. StuRat (talk) 22:55, 17 June 2011 (UTC)

It is not uncommon for a single photon to act like a circular wave, yet be detectable in only one place. See the classic double-slit experiment. One single photon, emitted from a source, moves through two slits, interfering with itself like a wave, as evidenced by the probability of detecting it varying according to wave interference. Yet it's just one single photon that lands in one single spot. Wnt (talk) 23:26, 17 June 2011 (UTC)

Can a single photon interfere with itself? I thought the interference only built up with many photons. [ignore that; I didn't properly take on board your "as evidenced by..."] But carrying on from what you say, does that mean that anywhere along the torch's sweep you have some probability of detecting a photon -- but whether you will or not at any given place can be determined only by trying to detect one, rather than it being (in principle) pre-determined from the moment the light left the torch (as is the case in the bullet analogy)? Does that question make sense? 86.160.209.60 (talk) 00:32, 18 June 2011 (UTC)

Well, that's where thing gets weird. On countless planets across the universe, people look up, waiting for that first photon your torch emitted. But only one shall find it. The photon has not decided, before it has been seen, where in the cosmos it might be. And yet once it decides on the world of its choice, all those countless others will look up in vain. One way to put it is that the state vector "collapses"; the detection removes the chance of it being detected anywhere else by a "spooky action at a distance". It is faster than light transmission of information, in a sense - the catch being, no one can say in advance where it will be found, so there is no predicting the information to be transmitted - just like with entangled particles. I am more fond of the transactional interpretation in which the detection sends a wave backward in time to match the first. Wnt (talk) 06:47, 18 June 2011 (UTC)

Thanks Wnt, your answers have been very ... ahem ... illuminating. 86.160.222.31 (talk) 11:19, 18 June 2011 (UTC)

The only reason you can detect the ripples on a pond is due to what you call "indirect evidence" (in this case, light reflecting from the ripples and reaching your eyes). Take this away (say, drop the rock into the water on a really dark night, or when blindfolded) and you'll only be able to detect them by actually dipping some part of your body into the water and feeling the ripples on your skin. Same thing with your flashlight -- the only way anyone can detect it is either if they're in the path of the beam, or by seeing light that has been scattered by the atmosphere. Also keep in mind that even in the absence of any scattering or absorption, the light will spread out and therefore decrease in intensity as the inverse-square function of the distance, so that even by the time it reaches the Moon, it will be so dim as to require advanced sensors for detection. -- An American ultranationalist 67.169.177.176 (talk) 23:30, 17 June 2011 (UTC)

NOTICE to whomever it may concern. It has come to my attention that your intra- and intergalactic electromagnetic intercourse may be impinged by radiations emanating from this planet on which I have assert right of occupancy as a partial spherical-polyhedral wedgeholder. I wish to assure you that no such radiation, coherent nor pulsed, is authorized as a communication by me nor is it emitted on my behalf. As a representative of decent humans I beg to offer apology for any inconvenience, and trust that no unpleasant misunderstanding will marr the mutual cordiality of our relations as neighbours. Klaatu barada nikto. Cuddlyable3 (talk) 14:12, 18 June 2011 (UTC)

Text readable only at low zoom

You probably know who this was. I am neither Leon Harmon nor Bela Julesz. I made this image using their idea. Cuddlyable3 (talk) 13:09, 18 June 2011 (UTC)

How do you explain something like this? The text seems almost completely unreadable at high zoom - yet in the fine print, which seems clearly legible to me, the exact same picture is present (use the Zoom on your browser if you don't believe me). Is there a scientific description of this phenomenon? Wnt (talk) 23:17, 17 June 2011 (UTC)

Seems to me like pixelation effects of a low-resolution text image. In other words, the letters are made of tiny pixels, which get magnified along with the image at higher zoom levels and act like a sort of pattern-disruptive camouflage for the letters. I know this from personal experience -- I've had much the same problem with the cover I created for my book, which had to be completely reworked as a result. 67.169.177.176 (talk) 23:40, 17 June 2011 (UTC)

(edit conflict) The rendering in squares of homogenous hues is dependent for clarity on failing visual resolution which occurs more at the smaller scale than at the larger scale. Bus stop (talk) 23:44, 17 June 2011 (UTC)

It's a "can't see the forest for the trees" issue. If you can make out individual pixels, your brain focuses on those, not the overall image. This is why zooming in on something only helps you make out detail to a point, then things start to get worse. StuRat (talk) 23:54, 17 June 2011 (UTC)

This is the phenomenon that Leon Harmon and Bela Julesz described in their 1973 Science paper, Masking in Visual Recognition: Effects of Two-Dimensional Filtered Noise -- exemplified by their famous pixelized image of Abraham Lincoln. Looie496 (talk) 00:10, 18 June 2011 (UTC)

Thank you for that link, Looie496. This paper is amazing. Nimur (talk) 00:53, 18 June 2011 (UTC)

The Abraham Lincoln picture is really cool. I just printed it A4 size, and when you hold it close in your hand it looks totally meaningless. If you then prop it up and walk away from it across the room, it gradually becomes clearer and clearer what it portrays. 86.160.209.60 (talk) 03:03, 18 June 2011 (UTC)

• Just curious, the OP says that the small text "seems clearly legible". For me, it is far from being "clearly legible" (though I am probably about 80% sure I can guess what it says). Is it "clearly legible" to everyone else? Btw, I can read the large version better if I almost close my eyes so that everything is very blurry and I can no longer see the sharp pixel outlines. 86.160.209.60 (talk) 00:37, 18 June 2011 (UTC)

• It depends on the resolution, display clarity/sharpness and viewing distance. It's illegible (can't even guess what it says) on my CRT at my default zoom. It's fairly legible on my LCD at default zoom. It's legible on my CRT at greater zoom although still not as clear IMHO. At in between zooms it becomes somewhat legible like for you. (Although I saw it on my LCD before this.) Past that it starts to become illegible again. If you want to do more experiments I suggest an image viewer with high quality zooming interpolation but fine zooming control. Nil Einne (talk) 00:57, 18 June 2011 (UTC)

Oh yes, of course. When I zoom to 200% it is easy to read. 86.160.209.60 (talk) 01:05, 18 June 2011 (UTC)

Note that the rendered text uses subpixel rendering, which makes an assumption about the layout of pixels in your monitor. Many modern monitors do not use the conventional "RGB" side-by-side rectilinear pixel. For example, an iPad display looks like this under a microscope. If text is rendered for sub-pixel antialiasing, assuming an RGB-horizontal array pixel geometry, it will look very different on an unconventional display. Nimur (talk) 01:14, 18 June 2011 (UTC)

Really? That blue text over there? Are you sure? It doesn't have the rainbow artifacts on the edges that I would normally associate with sub-pixel rendering. APL (talk) 02:11, 18 June 2011 (UTC)

I think it says "PREZOOM", whatever that means. Plasmic Physics (talk) 05:27, 18 June 2011 (UTC)

It does? I thought it said "FREEDOM". --Jayron32 05:30, 18 June 2011 (UTC)

Yes, it says "freedom". It's amazing that such a heavily pixilated image still contains enough information for our eyes to decode it. Dauto (talk) 07:49, 18 June 2011 (UTC)

If you think about it a bit, it's actually not particularly amazing. (Sorry to be a wet blanket.) The regular English alphabet contains 26 letters, represented by 52 symbols (upper and lower case). That's a bit less than 2⁶ unique symbols. In the image shown, there's an array of something like sixteen pixels for each letter. If we limit ourselves to turning each of those pixels (bits) on or off, we have 2¹⁶ possible unique 'characters'; roughly speaking, that's space for a thousand different alphabets. In practice, of course, it doesn't work quite like that. On the up side, we actually are allowed several different values possible values for each pixel—if we conservatively estimate each pixel might have one of four readily-distinguishable colors then there's room for a billion unique characters.

On the side of reality (the 'down side') human alphabets are generally not designed for efficient use of low-resolution pixels—though when we put our minds to it, we can certainly design such representations; consider Braille. Written characters are generally composed of strokes rather than arrays of stippled dots; this means that lines of adjacent pixels in their graphical representation will all have the same value, and will tend to be surrounded by buffers of wasted white space. As well, some characters have shapes that are similar to one another: o, c, e, for instance. Even then, though, we're partially rescued from ambiguity by our human pattern-matching abilities. If I see a the partially obscured W_k_p_d_a or __kipedia or Wikipe___, I've got a pretty good shot at correctly assigning the missing letters. TenOfAllTrades(talk) 13:36, 18 June 2011 (UTC)

Sorry but that's nonsense. Dauto (talk) 19:45, 18 June 2011 (UTC)

Sorry, I may have been too concise, or slipped in some oversimplifications in places. Which part did you not understand? TenOfAllTrades(talk) 21:01, 18 June 2011 (UTC)

Your demonstration is incomplete. Most of the pixel combinations do not represent anything. You have not assessed what fraction of these combinations can be used to represent letters. More to the point, the pixilated picture contains the same amount of info when you zoom in but becomes illegible. That means that some heavy information processing is being performed by the eyes and that's what makes it amazing. Dauto (talk) 03:03, 19 June 2011 (UTC)

Actually, it doesn't say anything - it's just a pattern of pixels that resembles what we think it ought to. It is simply a mind trick played by our brain, as it tries to make sense of the visual world. Plasmic Physics (talk) 08:44, 18 June 2011 (UTC)

Sorry but that is also nonsense. Dauto (talk) 19:45, 18 June 2011 (UTC)

-RunningOnBrains^(talk) 04:26, 19 June 2011 (UTC)

See CAPTCHA. Cuddlyable3 (talk) 13:19, 18 June 2011 (UTC)

Appealing to Plato's cave rarely contributes anything to a discussion. APL (talk) 20:40, 18 June 2011 (UTC)

What is Plato's cave? 67.169.177.176 (talk) 21:53, 18 June 2011 (UTC)

See Plato's Cave. Tevildo (talk) 22:02, 18 June 2011 (UTC)

June 18

Spotting Jupiter with the naked eye during daytime

This article mentions successful observations close to Sunset. But Jupiter now rises before the Sun does, and then you get a better opportunity to try to spot it when the Sun is in the sky, you just follow it starting at dawn for as long as possible.

I was wondering if people have done this and what the record (in terms of how high the Sun is in the sky when jupiter can no longer be seen) is. Count Iblis (talk) 03:26, 18 June 2011 (UTC)

It probably depends a lot on where you are, and what the atmospheric conditions are like when you are looking. Even if it is a nominally "clear" day with no clouds, there are a lot of factors which can affect if stars and planets are visible during the day. I have personally seen both Venus and Sirius during the day time, and the article on Sirius notes that it has a lower apparent magnitude than Jupiter, meaning that under ideal conditions, Jupiter should be visible when the sun is out. --Jayron32 06:06, 18 June 2011 (UTC)

There is a risk in doing this with a telescope, however: leaving the telescope statically pointed at any planet visible before sunrise means that the Sun could eventually enter the field of view–exploding the telescope. ~AH1 ^(discuss!) 15:12, 18 June 2011 (UTC)

Or permanently blinding you if you happen to be looking through it at the moment. 67.169.177.176 (talk) 20:25, 18 June 2011 (UTC)

If we(humankind) build 1 000 000 000 starships, Project Daedalus mass, that is around 50 000 tons each

If we(humankind) build 1 000 000 000 starships, around Project Daedalus mass, that is around 50 000 tons each.

We would use only resources found and mined on Moon. How big percent of Moon mass such advancement consume? Will humans who would still live on Earth notice any change to the ocean tides, how Moon shrink in size at nighttime?

Most of that 50 000 tons of every ship would consist of hydrogen, and to some degree of carbon/aluminum/lithium. Other elements would have trace mass compared to ship total mass.

I'm not talking about how industrialization would change texture of visible side of the Moon, only asking about visible perception of the size of the Moon and how huge would be consequences of building 1 billion of such massive ships on Earth ecology("tides" might not be the perfect choice of words, but Moon affect see level due to gravitational influence, please excuse my English).

76.64.30.242 (talk) 03:47, 18 June 2011 (UTC)

The Moon's mass is 7×10²² kg. Your ships mass only 5×10¹⁶ kg, and hence they would have essentially no impact on tides or Earth ecology. Dragons flight (talk) 04:40, 18 June 2011 (UTC)

Even if we would build 100 billions of such ships (lower estimate of number of starts in Milky Way), we would still get 5×10¹⁸ kg vs 7×10²². Am I correct? So that mean building 100 billion of starships each 50 000 tons would still barely affect Moon(in terms of size and diameter), in fact it would consume only less then one thousands of Moon mass? Do I understand yr calculations correctly? 76.64.30.242 (talk) 04:58, 18 June 2011 (UTC)

The moon has that much hydrogen? Plasmic Physics (talk) 05:24, 18 June 2011 (UTC)

I think it should have to have that much. If building those ships consume only 0.1% of Moon mass... But not sure. 76.64.30.242 (talk) 16:00, 18 June 2011 (UTC)

You might be interested in s:Advanced_Automation_for_Space_Missions. (I faintly remember there was once even a wikipedia article on that, but if so it has probably been deleted for political correctness or something like that.) 5BYv8cUJ (talk) 10:58, 18 June 2011 (UTC)

Question: How would that article be politically incorrect?

Question: Since when does wikipedia delete articles for being politically incorrect?

Dauto (talk) 19:36, 18 June 2011 (UTC)

You might be interested in Mogis. 5BYv8cUJ (talk) 20:47, 18 June 2011 (UTC)

The article you are linking to was only deleted on the German wikipedia which is well known for it's strict and controversy inclusion policy which as is most important in this context, rather different from the English wikipedia one. You appeared to be referring to the deletion of an article on the English wikipedia earlier so the policy of the German wikipedia is irrelevent to this discussion.

Your confusing and unsourced claims not withstanding, I find zero evidence we ever had an article on Advanced Automation for Space Missions. There is however extensive discussion at Self-replicating machine#Advanced Automation for Space Missions and Clanking replicator#Advanced Automation for Space Missions. There is brief mention in Asteroid mining#Self-Replicating Machine for material extraction. And evidentally the public domain I presume NASA study report from wikisource was used as the original source while writing parts? of Powder metallurgy and Cold welding and is used as WP:RS in Self-replication. Rather a lot of usage and mention for something we supposedly 'deleted for political correctness' which as 5BYv8cUJ pointed out doesn't even make sense (what's politically incorrect about it?).

Nil Einne (talk) 06:21, 19 June 2011 (UTC)

Answer to your second question: Since when does Wikipedia editorially trash formerly well-written articles for purposes of censorship and ban users such as myself for attempting to revert the damage caused in this manner? I tell you from personal experience, the commie WikiMafia (what the hell, no article?) has been doing this for a year or more! 67.169.177.176 (talk) 20:31, 18 June 2011 (UTC)

User:Paul Siebert has only ever been blocked once, for violating a 1rr on Mass killings under Communist regimes (not the article you linked to). If an article is under 1rr by arbcom restrictions (including discretionary) or by comunity consensus, it is a hardline rule with few exemptions. Nothing to do with censorship. If you add stuff to an article multiple times against multiple people removing it you will also break the 1rr. If you are unfamiliar with this, I suggest you read up on policy. The reason of course is to encourage discussion on a collaborative encylopaedia rather then blind edit warring which usually benefits no one. In fact, from my experience a lot of the time those who will accuse others of censorship when they remove something they want in the article and so are willing to break 1rr (or 3rr) will themselves be quite willing to do the same when it comes to adding content they do want. Or in other words a lot of the time the problem arises because of users inability to put aside their strong POV and to colloborate which will mean they are both willing to 'censor' content as well as add 'unwanted' content.

Incidentally, the 1 and only block for User:Paul Siebert was less than a year ago. Also 5BYv8cUJ and Dauto was referring to the deletion of articles which is a different thing from the removal of content from an article which is not delete. If you didn't even understand that, perhaps it explains any problems you may have had in collaborrating.

P.S. From further research the 1rr at Mass killings under Communist regimes arises from the well known Eastern European area. Anyone who has ever dealt with that area or looked at the infamous mailing lists knows it is a hell hole. Also I'm even less surprised User:Paul Siebert has had problems before. He? seems to think that 1rr means whoever has the most users 'wins' because they have greater numbers but while that may make mathematical sense, it makes no sense for anyone who has any understanding of the nature of wikipedia particular trouble articles under arbcom restrictions and high scrutiny. In reality if it ever comes down to that the article will quickly be locked and the participants in such a mass edit war will probably all be banned since 1rr is not and never a right and people who think it is or that it will be treated like one clearly don't understand how things work. Ironically though, User:Paul Siebert himself was clearly aware at the time that 1rr doesn't actually function to allow censorship since he's clearly aware people from either 'side' can be blocked.

Nil Einne (talk) 06:21, 19 June 2011 (UTC)

Thank you! Looks interesting. 76.64.30.242 (talk) 16:01, 18 June 2011 (UTC)

Why would we want to do that? Cuddlyable3 (talk) 12:57, 18 June 2011 (UTC)

Maybe if we have to evacuate all of mankind from Earth for some unforeseen reason (nuclear war, alien invasion, etc...) 67.169.177.176 (talk) 20:33, 18 June 2011 (UTC)

Maybe the hydrogen could come from hydrogen-alpha from the Sun. ~AH1 ^(discuss!) 15:10, 18 June 2011 (UTC)

?? I'm assuming that's meant as some sort of joke...? Hα (hydrogen-alpha) is a particular type of red light emitted by excited-state hydrogen atoms; it isn't a type of hydrogen. TenOfAllTrades(talk) 15:51, 18 June 2011 (UTC)

The fusion proposed for Project Daedalus can't do with Hydrogen (H¹) but needs Deuterium. 5BYv8cUJ (talk) 15:57, 18 June 2011 (UTC)

I know, but by the time we would seriously talking about mass production of star ships, fusion technology should be perfectly possible with ordinary hydrogen. Reaction is harder to archive, but fully possible. 76.64.30.242 (talk) 16:11, 18 June 2011 (UTC)

p+p-reactions depend on the weak force and therefore are very slow. I guess there are many "cheaper" alternatives. You might be interested in Astrochicken (as an idea, not to take it literally). 5BYv8cUJ (talk) 22:09, 18 June 2011 (UTC)

Astrochicken idea do outshined by what is known in my language as Von Neumann probes. Closest article here - Von Neumann probes. It is much easier to imagine them, but IMHO synergy/composite idea, when self replicating starships used for first couple generations, or even first few dozen generations, and then model switch to simple "build a single starship" for every star system out there would be more efficient, both in terms of complexity and in terms of speed of exploration. My current understanding (we talking about very distant future, like 70 years from now), there would be more economical to build not a Von Neumann probe per se ("just" a single one!), but instead robotic based industry on Moon or Eris, and use that body as a base to build a billion, or 5 hundreds billions probes to target every star system in Milky Way. If for any reason that would not be possible, then create similar base on nearby Alpha Centauri or any other nearby planetary system. And use it for mass production. But it looks like potential damage to Moon would be so negligible, thus Eris or close-by star systems do not have to be targeted. Not to mention trillions of bodies in Oort cloud... My original question was - how damaging would be such activity to the Moon? Hopefully no one cares about Eris. Seems that Moon still be pretty much intact after massproduction of billions of starships. Anyhow, here is science paper that was exploring different strategies of Milky Way exploration: http://www.rfreitas.com/Astro/ComparisonReproNov1980.htm Hope you find it interesting. 76.64.30.242 (talk) 01:51, 19 June 2011 (UTC)

Plenty of reasons possible, including but not limited to exploration of our Galaxy. Imagine NASA thousand years from now wanting to send probes to each star in Milky Way. Was wondering how big loss of mass Moon would suffer if matter would be taken solely from it. 76.64.30.242 (talk) 16:07, 18 June 2011 (UTC)

Space telescopes

--58.174.69.136 (talk) 06:39, 18 June 2011 (UTC)How can people using Space Telescopes work out details like the atmospheric composition of a planet 30 light years away? How do they achieve such amazing resolution and sensitivity?58.174.69.136 (talk)

I think that feat has not been completed yet. read spectral lines to understand how that can be done. Dauto (talk) 07:19, 18 June 2011 (UTC)

Here's an example of detecting Oxygen on an exoplanet approximately 150 light years away. http://www.spacetelescope.org/news/heic0403/ Pretty good resolution and sensitivity I believe. — Preceding unsigned comment added by 101.169.7.177 (talk) 09:55, 18 June 2011 (UTC)

Accuracy of Altitude measurements

When the "height above sealevel" of somewhere like Mt Everest is given, what exactly is the reference system used to compare sealevel and altitude? Could it be "distance from the centre of the earth"? In that case sealevel must have a pretty wide range of "distances from the centre of the earth" with the earth being the shape it is? (ie bulged out at the equator etc). Is the centre of the earth an easy thing to define? I assume earth-orbiting satellites travel around the "centre of mass" of the earth, so radar altimeter measurements would use that as their reference point? Is it possible to tell if Pacific islands like Kiribati are "sinking" (as in getting closer to the centre of the earth) or suffering from local increase in sealevel? I know this is a lot of questions, but any answers or links to appropriate reading would be much appreciated — Preceding unsigned comment added by 58.174.69.136 (talk) 07:08, 18 June 2011 (UTC)

These days points of altitude are referenced from the World Geodetic System 86. Satellite interferometry can even measure continental drift of a few centimetres per year. --Aspro (talk) 07:17, 18 June 2011 (UTC)

What you ask is a major surveying challenge on which whole books have been written. The idea is to work out where the sea level would be close to the mountain and then work out the elevation from that. Graeme Bartlett (talk) 11:03, 18 June 2011 (UTC)

The world's tallest mountain in terms of the greatest distance between the Earth's centre and the mountain's peak is Mount Chimborazo. As for Pacific nations such as Kiribati and Tuvalu, they are being innundated because of current sea level rise. When land actually drops and sea level stays the same, this is subsidence but the result is the same: saltwater intrusion. ~AH1 ^(discuss!) 15:07, 18 June 2011 (UTC)

See the article geoid, which I believe describes what Graeme Bartlett is referring to. The geoid is a mathematical description of a surface which would coincide exactly with the mean ocean surface of the Earth. The height above sealevel is calculated relative to the geoid. --NorwegianBlue ^talk 16:26, 18 June 2011 (UTC)

Lunar eclipse

Ok, so I imagine this will be one of those "stupid questions", but nonetheless: Recently there was a lunar eclipse with a lot of media attention. As I understand it, a lunar eclipse happens when the alignment of Earth's shadow in front of the Sun obscures, or partially obscures, the visible moon. So what is the difference between a lunar eclipse, and the phases of the moon? Don't we often see the shadow of the Earth affecting visibility of the moon; i.e a crescent moon, half moon, etc.? Quinn ^{❀ BEAUTIFUL DAY} 07:10, 18 June 2011 (UTC)

The phases of the moon have nothing to do with the earth's shadow. They are simply the result of where the moon is in relation to the sun and the observers, us. Think about looking at a ball which is lit only by a single light off to one side. The lit up part you see is equivalent to a phase of the moon. The article Lunar phase may help, but it looks a bit heavy to me. HiLo48 (talk) 07:16, 18 June 2011 (UTC)

Shit. My first instinct was correct: It was a stupid question. Phases of the Moon specifically states that the lunar phases are not a result of Earth's shadow. Good grief! But in my defense, Lunar eclipse really offers no help with this question. Quinn ^{❀ BEAUTIFUL DAY} 07:19, 18 June 2011 (UTC)

An eclipse of the Moon is always the Earth's shadow passing across a full Moon. Cuddlyable3 (talk) 12:49, 18 June 2011 (UTC)

The phases of the Moon are caused by the Moon's shadow, so to speak, just like nighttime on Earth is caused by the other half of Earth blocking the Sun's light. During a total lunar eclipse, the Earth's umbra obscures the entire Moon. What usually happens during a full Moon instead is that the Moon's tilt above or below the Earth's ecliptic is too far away from any part of Earth's shadow during the greatest point of Full Moon that the Moon completely misses the shadow and you get no eclipse; conversely, during a solar eclipse, the shadow cast by the Moon lands on the Earth when it would usually miss the Earth completely. ~AH1 ^(discuss!) 15:04, 18 June 2011 (UTC)

And, as far as observations go, a lunar eclipse varies from a change in phase in two ways:

1) It's much quicker, lasting only minutes instead of about 28 days.

2) Since the radius of the Earth is larger, the radius of the shadow cast on the Moon is larger during a lunar eclipse. StuRat (talk) 23:03, 18 June 2011 (UTC)

Another way of thinking about the difference is this: Lunar phases involve only 2 celestial bodies, the Moon and the Sun. We here on Earth are simply observers, and we could just as well be observing from Mars (assuming we had a telescope that could let us observe from that distance). But a lunar eclipse involves 3 bodies: the Moon, the Sun and the Earth. The Earth's shadow on the Moon is a fundamental part of this scenario. -- Jack of Oz ^{[your turn]} 23:10, 18 June 2011 (UTC)

Kill or capture a household fly

How can I kill or capture an irritating fly in my living room? Whacking it with a rolled-up newspaper would damage things, and I always miss. Going to buy some fly paper would take too long. In the past I captured a fly alive by covering it with a very large plastic bag, but I havnt got a large enough bag, the fly is very agile, and the clutter in the room makes it more difficult. Thanks. 92.29.126.21 (talk) 11:59, 18 June 2011 (UTC)

You must disable it. You can buy a charged racket and wave to those fly. When the fly pass though those grid, its nervous system will temporary disabled.Nilman (talk) 12:31, 18 June 2011 (UTC)

Take a fairly large, preferably see-through container which has, or in which you can create, a small entrance aperture: an empty 2-litre soft drinks plastic bottle might work, or an old mesh meat cover.

It helps if you can make the entrance convex to the inside of the container, perhaps by making and fitting an open ended paper tube in it. In the case of the plastic bottle, you could cut off the top just below the shoulders, reverse it to sit in the top of the main body, and tape it in place.

Put something smelly and attractive to the fly into it.

Wait until the fly enters the container, then close the aperture. Because the entrance/exit is small, difficult to find and (depending on the created configuration) difficult to negotiate from the inside, the fly will not have time to escape even if it sees you coming.

This is an adaption of the old method, common in freshwater angling, of knocking a hole in the recessed conical bottom of a wine bottle, baiting the closed neck, submerging the apparatus in a stream, and using it to catch small fish for use as bait for larger fish. {The poster formerly known as 87.81.230.195} 90.201.110.145 (talk) 12:33, 18 June 2011 (UTC)

Butterfly net. Cuddlyable3 (talk) 12:43, 18 June 2011 (UTC)

I can think of two ways. One is to create a cone-shaped container with some meat or other aromatic food in the middle, and a small hole at the bottom through which the fly can fly in, and hang it up in the room. The fly is unlikely to fly underneath in order to get out. Also, if you have a see-through curtain in any room, try to wait until the fly gets close to the window there. Trap the fly between the curtain and the window, and do whatever you need to do next. ~AH1 ^(discuss!) 15:00, 18 June 2011 (UTC)

What I do is wait until the fly sits on a wall, get a drinking glass and a piece of paper large enough to cover the glass. Then put the glass slowly over the fly. You then gently move the paper betweeen the wall and the glass, this pushes the fly into the glass. You then take the covered glass outside and release the fly. Usually this takes me one or two minutes per fly. If the fly is flying around a lot, then this won't work well, but then you can move the fly by making the room dark, open a door to another room and put a light on in that room. The fly will then fly toward the light and thus leave the room. Count Iblis (talk) 15:32, 18 June 2011 (UTC)

A flyswatter

Flyswatter. 75.41.110.200 (talk) 15:45, 18 June 2011 (UTC)

Eventually a fly goes to the light in the window. Given drapes, shades, etc., it is difficult for it to get back, and easy for misfortune to befall it. But when I was younger my pleasure was to do battle with the fly using a can of Lysol (essentially spray alcohol) and a lighter. It only harms the wings, and then the rest of the fly is yours to experiment with at your leisure. I think I blame Dragonriders of Pern for that. ;) Wnt (talk) 18:35, 18 June 2011 (UTC)

No-one's mentioned just squirting it with bug spray yet? Flies are very, very quick - but even they struggle to dodge an aerosol spray (most of the time anyway). --Kurt Shaped Box (talk) 18:46, 18 June 2011 (UTC)

Once upon a time some brilliant person cogitated very deeply on this very problem, and came up with a brilliant and creative solution. It is known as a "flyswatter". Looie496 (talk) 18:55, 18 June 2011 (UTC)

Incidentally, the reason a flyswatter works better than a newspaper is that it has holes to let the air pass through. Thus the flyswatter moves faster, due to the lack of air resistance, and there's no whoosh of air in front to blow the fly out of the way.

Another approach I've had luck with is to open a window (yet leave the screen in). The fly will go to the screen, then I close the window behind it and leave it closed until the fly dies (a few days, typically). I usually "mark" the window in some way as a reminder not to open it too soon. I have one trapped right now, as a matter of fact, and a toilet paper roll tied to the pull string for the blinds is my reminder.

I suggest you close doors to restrict the fly's movements, and then open all the windows it can reach, to maximize the chances of catching it quickly. Also, a warning on fly paper, it's very messy, getting brown glue all over anything it touches. StuRat (talk) 19:28, 18 June 2011 (UTC)

That sounds like a lot of trouble to kill the fly rather than just letting it fly away outside. Are fly corpses useful? Rckrone (talk) 19:57, 18 June 2011 (UTC)

"Letting it fly outside" involves leaving a door or window open (without a screen) until it decides to leave on it's own, by which time several more insects are likely to have flown in. StuRat (talk) 22:29, 18 June 2011 (UTC)

Depending on the species of fly, a flyswatter may not be effective unless the fly is at rest on a surface. I'm not entirely sure what species of fly this is (it's smaller than a bluebottle, medium-sized-ish) - but there's one in the UK that's very good at evading attempts to swat it in mid-air. FWIW, a vacuum cleaner hose can be good against flying insects - I once sucked up 30+ wasps from my living room (nest was in an air vent) with the Dyson... I don't see why it wouldn't work on flies. --Kurt Shaped Box (talk) 20:36, 18 June 2011 (UTC)

I've also used a vacuum cleaner on stinging insects. The big advantage is that they don't see it as an attack, so don't get angry and try to sting you, unlike trying to swat them. However, this doesn't apply to flies, and flies are also often faster with a more chaotic flight, so catching them this way may not work. StuRat (talk) 22:39, 18 June 2011 (UTC)

Why don't you just try an exploit, doing something useful with it? No, no, thanks, don't feel worthy enough for that myself, thank you all the same. 5BYv8cUJ (talk) 19:47, 18 June 2011 (UTC)

There are self-replicating robots available that catch flies and use them to make copies of themselves. Unlike sprays, fly swatters, etc. they are free of charge.Count Iblis (talk) 02:51, 19 June 2011 (UTC)

True. AndyTheGrump (talk) 03:01, 19 June 2011 (UTC)

You might want to make sure it's not The Fly. "Be afraid. Be very afraid." HiLo48 (talk) 03:00, 19 June 2011 (UTC)

Or better yet, the 1950s version with David Hedison while he was still known as Al. "HELP ME! HELP ME!"[16] We also need a companion to the flyswatter pic: The Far Side cartoon called "the last thing a fly ever sees."[17] ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:46, 19 June 2011 (UTC)

As a practical matter, one trick is to position your hands apart and a few inches above the fly. As soon as it moves, clap your hands together, and there's a reasonable chance you'll get it. Then, of course, wash up. You don't know where they've been (although you can guess). ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:55, 19 June 2011 (UTC)

Does Gamma Ray travels slower than Light Speed?

Those are from Wikipedia:Gamma ray burst: "gamma-ray bursts are thought to be highly focused explosions, with most of the explosion energy collimated into a narrow jet traveling at speeds exceeding 99.995% of the speed of light." But ALL electromagnetic wave travels as a constant speed in vacuum. Gamma ray is a kind of electromagnetic wave. Gamma-ray travels at 99.995% of the speed of light. So there's a contradiction, Why?Nilman (talk) 12:16, 18 June 2011 (UTC)

I don't really know but if you think of the "gamma-ray burst" not as the gamma rays but as the explosion that accompanies and/or generates them, this would resolve the paradox. 5BYv8cUJ (talk) 12:40, 18 June 2011 (UTC)

As 5BYv8cUJ says, the explosion itself is of matter: just how this is partially converted into gamma rays is not yet properly understood, and is the subject of ongoing research. See the Emission mechanisms section further down in the article from the quote, and the longer and more detailed article Gamma-ray burst emission mechanisms to which it links for current theories. {The poster formerly known as 87.81.230.105} 90.201.110.145 (talk) 12:46, 18 June 2011 (UTC)

That's the speed of the jets. The gamma rays move at the speed of light. Dauto (talk) 19:29, 18 June 2011 (UTC)

Did the military have mobile phones?

In an episode of the 1960s series I Dream of Jeannie, Don Rickles played a senior military officer who was putting the astronauts through rigorous military training on a remote area of what I believe was a military base. He stayed in touch with the people in charge using a telephone in a bag of some kind. It looked like regular phones looked back then, and it had a wire connected to something. The mobile phone article doesn't seem helpful.Vchimpanzee · talk · contributions · 16:19, 18 June 2011 (UTC)

Our article on field telephones describes these devices. Looie496 (talk) 18:06, 18 June 2011 (UTC)

When I think of field phones I always imagine some pioneers laying wires. I guess by the sixties these would have been replaced by wireless walkie-talkies. But still without any possibility to play pac-man.5BYv8cUJ (talk) 18:42, 18 June 2011 (UTC)

Actually, two-way radios first appeared during World War 2, but they were big and heavy (typically taking up a whole standard-issue Army backpack). 67.169.177.176 (talk) 20:38, 18 June 2011 (UTC)

Yes, so only a few soldiers were assigned to carry them, meaning anyone isolated from those soldiers was out of communication with everyone else. Also, since there weren't many, they could all be destroyed in battle, cutting off communications with the entire group. StuRat (talk) 22:35, 18 June 2011 (UTC)

Wireless telephones were first invented about a century ago, but the evolution of their practical usage was rather slow until the last 20 years or so. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:40, 19 June 2011 (UTC)

Hitting cows on their noses

If you hit an imposing cow on the nose with a stick or a fist, will it likely turn more aggressive or turn and leave? --2.216.135.118 (talk) 19:25, 18 June 2011 (UTC)

Depending on the circumstances and the cow, it might do either. However, since "more agressive" may include seriously injuring or killing you, which a cow can do quite easily, you ought to avoid getting into such close contact with cows in the first place until you know what you're doing. In the UK, one or two farmers - who do know what they're doing - are nevertheless killed by cows every year, as sometimes are country walkers who venture into fields of cows and somehow annoy one or more of them (usually by having a dog with them). {The poster formerly known as 87.81.230.195} 90.201.110.209 (talk) 19:47, 18 June 2011 (UTC)

Cows become very aggressive when they have their young calves with them. They stampede and/or trample people to death. So stay away from cows with calves. 92.29.112.181 (talk) 19:54, 18 June 2011 (UTC)

Cows are inquisitive, and don't normally attack humans (though a bull might), but there are three situations when they might be dangerous:

1. When a person is holding a dog (which the cow sees as a threat), so it is always wise to allow a dog to look after itself in an emergency.

2. When they panic and "stampede", trampling anything that gets in the way, so move slowly to avoid frightening them.

3. When anything gets between a cow and its offspring (in common with most mammals, including humans).

A stick might help if a cow is becoming over-inquisitive, but will not make any difference to a panicking cow and probably not to one protecting its calf. Dbfirs 06:45, 19 June 2011 (UTC)

What's an "imposing" cow? One that always shows up right at suppertime? ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:38, 19 June 2011 (UTC)

Relative pulling power of one horse

I remember being told at school (decades ago) that there was an experiment or comparison of horse pulling powers done about 200 - 300 years ago, which showed relative powers (if I recall correctly) of: - horse can carry a few hundred pounds on its back (this was pre-metric) - pull about a ton in a cart on decent road - pull 8 tons on a metal rail - pull 70 tons in a canal boat

Is this correct? Is there a specific experiment or something that proved this, or did the knowledge just accumulate over time? — Preceding unsigned comment added by J987 (talk • contribs) 20:44, 18 June 2011 (UTC)

See Horsepower. James Watt is _reputed_ to have carried out the experiment (in 1782) to determine a suitable unit of power for his steam engines, but whether his results (as opposed to the magnitude of the unit) are reliable is a matter of debate. Tevildo (talk) 21:56, 18 June 2011 (UTC)

In the first case, the horse is actually carrying the weight, while in the rest, assuming level ground and no air or water flow, all that must be overcome is friction. In the cart and rail cases, there is a static friction to overcome to get things started (they must assume this to be worse for the cart). In the boat case there is none of that, and only the fluid resistance of the air and water (which grows with speed). Thus, to move the boat very slowly should require almost no effort, assuming no winds or water current. In reality, I'd expect how much a horse can haul to vary dramatically depending on the horse, lubrication of the cart and train, condition of the road and track, and the winds and water currents. StuRat (talk) 22:47, 18 June 2011 (UTC)

You don't have to do any work to carry a weight unless you are lifting it. As long as the horse's back doesn't rise and fall too much as it moves, the energy required probably isn't much greater than overcoming friction in the other scenarios. (There may be some energy required to maintain the muscle tension required to hold up the weight, but that's biology not physics, so I don't know anything about it!) --Tango (talk) 22:55, 18 June 2011 (UTC)

It gets complicated. Since horses don't have wheels on them, they need to to lift their legs to move. The more weight distributed on each leg (in addition to their own weight), the more work this requires. And they don't get all this energy back when they put the leg back down again, so energy is lost. Depending on how the weight on their back is positioned, they may be able to reposition it a bit by their movements, and thus have less on each leg as they lift it. This also would be affected by the type of walking or running done by the horse, as each has different legs off the ground at once. Converting all this to physics formulae would be quite an effort. StuRat (talk) 23:09, 18 June 2011 (UTC)

They are only lifting the leg, so only the weight of the leg matters. The weight of the load will inevitably shift to the other legs, but that doesn't take energy. The weight of the load is only important if you actually increase the height of the load (which may happen slightly due to way the horse moves and will obviously happen if the horse goes up hill). --Tango (talk) 00:42, 19 June 2011 (UTC)

June 19

Iraqi National Oil Company

Dear Wikipedia,

Why is there nothing on the Iraqi National Oil Company since 1987 on your page (http://en.wikipedia.org/wiki/Iraq_National_Oil_Company)?

Are they a publicly traded company?

How would one invest in INOC?

Thanks,

50.15.18.118 (talk) 00:09, 19 June 2011 (UTC)

The event in 1987 it mentions is it merging with the oil ministry, so it ceased to exist as an independent company at that point. That's why the article doesn't go any further. --Tango (talk) 00:38, 19 June 2011 (UTC)

The page on Iraqi Oil Ministry isn't exactly stellar either. There must be some company that owns Iraq's oil... 50.15.18.118 (talk) 07:17, 19 June 2011 (UTC)

Lunar eclipse (why not with every full moon ?)

Why isn't there a lunar eclipse every time there's a full moon? --75.40.204.106 (talk) 00:57, 19 June 2011 (UTC)

(ec) I changed the title to distinguish this from the other lunar eclipse question a couple above this one. This question was also answered there, but, to reiterate, most times it passes behind the Earth, the Moon is either above or below the line formed by the Earth and Sun. Thus, the Earth's shadow falls above or below the Moon. Only when they happen to align does a lunar eclipse occur, or a solar eclipse if the Moon is between the Sun and Earth. StuRat (talk)

Because the Moon's orbit around the Earth is inclined by about 5 degrees relative to the Earth's orbit around the Sun. The Earth casts a conical shadow in space and the inclination of the Moon's orbit means that most of the time it either passes above or below that cone. It is only when the full moon happens at the same time as the Moon's orbit crosses the plane of the Earth's orbit that we get a lunar eclipse. --Tango (talk) 01:12, 19 June 2011 (UTC)

If the moon's orbital plane around the earth were the same as the earth's orbital plane around the sun, we would get a lunar and a solar eclipse every month. They aren't, so we only get lunar and solar eclipse pairs a couple or three times a year. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:36, 19 June 2011 (UTC)