Wikipedia:Reference desk/Archives/Science/2011 August 11

= August 11 =

Influenza
Besides death, can influenza among native people, who lack the immunity, lead to blindless or eye damage?


 * Google "blindness influenza". I got:


 * BLINDNESS AS AN IMMEDIATE SEQUELA OF INFLUENZA: RECOVERY
 * www.ncbi.nlm.nih.gov › Journal List › Br Med J › v.1(3189); Feb 11, 1922by SE Denyer - 1922
 * BLINDNESS AS AN IMMEDIATE SEQUELA OF INFLUENZA: RECOVERY. Stanley E. Denyer. Full text. Full text is available as a scanned copy of the original print ...
 * Reversible blindness in optic neuritis associated with influenza ...
 * www.ncbi.nlm.nih.gov/pubmed/453752by HD Perry - 1979 - Cited by 22 - Related articles
 * A patient is reported in whom bilateral optic neuritis developed following ...
 * Bilateral optic nerve atrophy and blindness following swine influenza
 * www.ncbi.nlm.nih.gov/pubmed/7103325by KL Macoul - 1982 - Cited by 6 - Related articles


 * μηδείς (talk) 09:32, 11 August 2011 (UTC)

Airport and weather station identfiers
Looking at weather observations and forecasts for the Dodge City, Kansas NWS office, I see Medicine Lodge, Kansas referred to as KP28. I'm used to locations being given their 3 or 4 letter identifier based off of the airport in town (for example, KSLN/SLN for Salina, KS, KSMF/SMF for Sacramento, etc.), but Medicine Lodge's airport appears to be identified as K51. Another example of a city that seem to have an odd identifier like this is Eureka, Nevada (KP68) with an airport identifier of EUE or 05U. As far as I knew, all US ASOS/AWOS stations were either co-located with airports (hence the name "Automated airport weather station") and given that airport's identifier or else located in a climatologically important location (for example ) and given a related, still alphabetical identifier (as the example was). This brings up two mysteries to me: 1. Why do Medicine Lodge and Eureka's airports (and a couple others I found that don't have an associated weather station) have identifiers with numbers in them (I thought it was common practice for them to be all letters), and 2. Is there some systematic way of assigning weather station identifiers like P28 and P68 that I haven't heard of, or were they probably randomly assigned? Ks0stm (T•C•G) 07:21, 11 August 2011 (UTC)


 * See location identifier. Three letter ID codes are IATA airport codes, four letter codes are usually ICAO airport codes.  All US airports and weather stations are assigned FAA location identifiers consisting of three or four letters and numbers.  For large airports, the FAA id is generally chosen to match either the IATA or ICAO designation, but many small airports don't participation in either standard.  These smaller airports generally receive FAA codes with numbers in them (though all codes have at least one letter).  IATA codes are generally assigned on a first-come, first-serve basis by request (but only to airports above a certain size).  Frequently the code is somehow related to the airport's name.  ICAO codes are partially systematic: the first letter designates the country or region, the second letter usually corresponds to the first letter of the city / county the airport was located in at the time of the assignment.  The last two letters are assigned in some other way I'm unsure of (by request, probably).  By convention, ICAO ids may never be reused.  I have no idea what process the FAA uses in assigning numbered ids.  Dragons flight (talk) 19:03, 11 August 2011 (UTC)

florida homes
do homes in Orlando, fl have insulation — Preceding unsigned comment added by Von1235 (talk • contribs) 10:27, 11 August 2011 (UTC)


 * I suppose yes. Insulation is not just to insulate you from the cold outside. It's also meaningful to isolated A/Ced rooms from the heat outside. — Preceding unsigned comment added by 88.14.196.229 (talk) 11:48, 11 August 2011 (UTC)


 * In order to answer your questions completely, please let us know why you assume that there are any homes in the United States that do not have insulation. Building codes have been in place throughout the United States for a very long time and they uniformly require insulation to protect the house from both cold and heat. -- k a i n a w &trade; 12:49, 11 August 2011 (UTC)
 * Certainly houses throughout the U.S. are insulated. Whether or not homes are insulated depends on what the person's home is. People who live in their car, or under a bridge, do not have insulated homes. Pais (talk) 12:57, 11 August 2011 (UTC)
 * You might not find insulation in houses in Hawaii, but other then that, I would expect most houses in the US to have at least some insulation. At Pais, around here, we call people who live in a car or under a bridge homeless.  Oh, and any house with electricity will have electrical insulation.  I assumed above you are talking about thermal insulation.  Googlemeister (talk) 12:59, 11 August 2011 (UTC)

need some explanation about electrical transformers
there are many types of transformers using in electircal power system ,,,at what bases it is selected is there any site to refer,,,i need application of the transformers which having different type of connections... — Preceding unsigned comment added by Rajivelectrical (talk • contribs) 14:15, 11 August 2011 (UTC)
 * The article Transformer will help you. Cuddlyable3 (talk) 19:33, 11 August 2011 (UTC)

How is commercial-scale vacuum-sealing done?
Like with spaghetti jars, for instance. There's a slight vacuum there because the first time you twist it open, the metal lid pops up. At the part of the factory where they put the lids on, how do they get that bit of air out right before the lid goes on? Do jarring factories do their lidding in a depressurized section? 20.137.18.50 (talk) 16:20, 11 August 2011 (UTC)
 * see Canning the can is sealed with its contents hot, vacuum develops as it cools--Digrpat (talk) 16:26, 11 August 2011 (UTC)
 * ec)Jars typically develop a slight vacuum because they are filled and closed in a hot state. As they cool down, the air volume in the little bubble at the top reduces and some of the water vapor in the air condenses, leading to the development of a small vacuum. You get the same effect if you make preserves yourself and close the jars with the typical rubber seal/glass lid while hot. --Stephan Schulz (talk) 16:37, 11 August 2011 (UTC)

constellations and their relationship to spiral arms.
Are some constellations in other spiral arms and others outside of spiral arms.

I notice that some arms have names such as Norma or Perseus, are the constellations in there or is it that we are using the constellation as a pointer?

Please don't start off your post with "constellations are random .....etc", I am trying to visualize our place alongside them in relation to the arms and its very confusing. :) — Preceding unsigned comment added by 92.30.186.14 (talk) 17:47, 11 August 2011 (UTC)


 * First, it doesn't make sense to discuss the location of constellations within 3D space, as they are 2D projections without depth. However, regarding the stars that make up the constellations: most stars visible to the unaided eye are within our spiral arm; some visible stars are in other arms and some in interarm space.  Thus, I expect that most major constellation stars will have a similar distribution.  The Orion–Cygnus Arm is 3500 by 10000 light years in size; only Eta Canis Majoris (3200 ly distant) approaches potentially being located elsewhere on the list of the 90 brightest stars from Earth.  As for naming the arms of the Milky Way, they are general references to direction -- one looks through the 2D windowpane of Constellation X to observe some object at arbitrary distance.  &mdash; Lomn 18:02, 11 August 2011 (UTC)


 * Also, I don't think all of the points in constellations are single stars. Some may be star clusters, nebulae, or entire galaxies. StuRat (talk) 19:08, 11 August 2011 (UTC)


 * We're using the names of the constellations to label the spiral arms. If you consider that the constellations were identified and labelled long before the spiral nature of the galaxy was discovered, this should be reasonably obvious. --TammyMoet (talk) 19:17, 11 August 2011 (UTC)




 * Constellations are random...


 * Kidding. :P But yeah, yes and no.


 * Like Lomn said, constellations are basically 2d projections of objects in 3d space. Don't think of constellations as a single group of stars close together. They're not. They can be millions of light years away from each other, thus judging 'our place alongside them' by looking at them is basically useless for determining our actual spatial location. In the constellation Andromeda for example. One of its member 'stars', formerly known as n And, is Messier 31 - better known as the Andromeda Galaxy. And obviously the Andromeda Galaxy is not within the spiral arms of this galaxy. Others are Omega Centauri and Triangulum Galaxy.


 * You're correct though that they are named because they are close to or intersecting a particular constellation. Not in the literal sense that they pass through a constellation, but in the relative sense in that you can see them where you can make out the pattern of a particular constellation. That is actually how we usually convey the location of something in space, because constellations are basically fixed and won't change for thousands of years, if at all (unlike planets). e.g. People telling you that NGC 1333 is in the Perseus Constellation basically mean that you can see NGC 1333 by looking at the general direction of where Perseus is. Also notice how astrologers will say "Mars is in Sagittarius" or something like that, basically meaning that Mars is passing through an area of the imaginary projected sky where Sagittarius is.


 * However, again this is completely relative to our point of view. Move to a far enough star and this method basically becomes useless. The Perseus arm would not anymore be near the constellation Perseus, for instance. In fact we wouldn't actually see the constellation Perseus at all. It's constituent 'stars' would be scattered all over the sky, depending on how far you went from the Solar system.


 * I highly recommend you watch the Powers of Ten video.--  Obsidi ♠ n   Soul   19:58, 11 August 2011 (UTC)


 * While most of this is good information, I need to nitpick a bit. No stars we can resolve with the unaided eye are "millions of light years away", and I don't think any extragalactic objects visible to the naked eye appear star-like (the brightest quasar is more than 6 magnitudes too dim). --Stephan Schulz (talk) 20:43, 11 August 2011 (UTC)


 * Heh, I meant the Andromeda Galaxy of course (2.54 million light years away), which yes was formerly seen as a star (Andromeda Galaxy), as was Omega Centauri (by Ptolemy and Bayer). All of the deep sky objects I've mentioned are visible to the naked eye. I was driving the point of how even if the 'stars' are grouped in a constellation, that doesn't automatically mean they are near each other.


 * However, note how I placed quotation marks on 'stars' - meaning the constituents of a constellation as we've traditionally perceived them, not actual stars. I debated whether to call them points or something, heh, I have no idea what you'd call the members of a constellation. Elbows of Orion? :P --  Obsidi ♠ n   Soul   21:27, 11 August 2011 (UTC)


 * This page notes that SN 1987A (a supernova, and therefore a single star) was visible to the naked eye (third magnitude!) at its peak. That was out in the Large Magellanic Cloud, 168,000 light years away (so not quite the "millions" we're hoping for, but still quite a respectable distance).  In principle, a bright supernova in a nearby galaxy (Andromeda, Triangulum, etc.) could also be a naked-eye object for a few days; for just a little while the most distant naked-eye star could be "millions" of light years distant.
 * In a similar vein, the gamma-ray burst GRB 080319B peaked at a visual magnitude of 5.8, and should have been visible to the naked eye for roughly 30 seconds before fading from view. If anyone had been looking in the right place at the right time, they would have seen light from an object 7.5 billion light years away: more than two thousand times the distance to Triangulum, the usual most-distant naked-eye object.  For a very brief period, these bursts could give us a view of the most distant stars&mdash;at least, assuming that our association of these events with supernovae is correct.  TenOfAllTrades(talk) 03:28, 12 August 2011 (UTC)

Badger Diet Question
Does the American Badger ever eat chickens or ducks? Pinguinus (talk) 17:59, 11 August 2011 (UTC)


 * Badgers will eat pretty much anything they can grab. So, some badger at some time certainly ate a chicken or a duck. However, this is out of the norm. Badgers tend go after burrowing animals. Chickens and ducks don't tend to burrow. -- k a i n a w &trade; 19:34, 11 August 2011 (UTC)

Tides
Does the moon's gravity affect the land mass at all, given that it attracts the water on Earth? Aquitania (talk) 19:13, 11 August 2011 (UTC)


 * Yes. I believe there is a land tide of about 1 meter. Cuddlyable3 (talk) 19:30, 11 August 2011 (UTC)


 * See Earth tide. Dragons flight (talk) 19:32, 11 August 2011 (UTC)


 * Also note that tidal forces on the land create heat in the Earth's interior, along with radioactive decay. This keeps the interior molten, which in turn supports the Earth's strong magnetic field, which deflects the solar wind, preventing the atmosphere from being blown away. StuRat (talk) 00:18, 13 August 2011 (UTC)

Black hole and stellar evolution
How is black hole treated as part of stellar evolution? How do scientists arrive at the conclusion? Aquitania (talk) 21:21, 11 August 2011 (UTC)
 * I would look to the WP article for Stellar Evolution on Black Holes as a start. Essentially, when a star runs out of fuel there is nothing to counteract gravity pulling it together. Depending on the total mass (and whether it goes supernova) gravity overcomes various nuclear forces. For the heaviest star, it forms a black hole. What specifically were you looking for? Black holes are also important in Galaxy Formation. Rosilisk (talk) 21:46, 11 August 2011 (UTC)


 * To answer in a slightly different way: scientists first realised that black holes ought to exist because the mathematics told them so, including that some stars ought, by the maths, to collapse into black holes at the end of their lives (black holes can also arise by other causes). Then they went looking for evidence of such black holes and eventually found it, confirming the theories. {The poster formerly known as 87.81.230.195} 90.197.66.65 (talk) 23:56, 11 August 2011 (UTC)
 * It has been hypothesized that material which falls into a black hole emerges on the "other side" as a new Big bang. The idea is neither verifiable nor falsifiable. Cuddlyable3 (talk) 10:30, 12 August 2011 (UTC)

state of a dissolved solid (chemistry)
When a solid dissolves in a liquid, is it considered a change of phase? Is the dissolved solid a liquid? In that case, does the solvant cool down to provide the energy for melting? — Preceding unsigned comment added by 90.28.53.74 (talk) 23:10, 11 August 2011 (UTC)
 * The solution, considered as a whole, will have the state of the solvent. The solute is usually described as being whatever phase it would be if it weren't dissolved (eg. the salt in salt water is referred to as being a solid and the carbon dioxide is referred to as being a gas), but they don't really have their own phase. They are just part of the solution. I'm not sure about the thermodynamics of dissolving, but it looks like this is the article you need to read: Enthalpy change of solution (I haven't read it myself, so I'm not sure how accessible it is). --Tango (talk) 23:57, 11 August 2011 (UTC)
 * One thing to remember is that the "three phases" of matter are like the "five senses" or the "four tastes" or other such lists; just as in reality you have many more than five senses, and you can detect more than four tastes, and of course there aren't just the three phases of "solid-liquid-gas". The "three phase" model is used as a heuristic or pedagogical model; designed to give a basic introduction to the lay person or as a means to build upon for students so that they can "add" to the model later in their education and create a more complete picture.  In reality, the "three phases" system breaks down pretty easily once you start considering the edge cases, and there are a LOT of edge cases.  The problem of solutions is actually pretty easy, but how does one correctly classify colloids like gels and aerosols and things like that?  What about glass, which has long presented problems for proper classification?  The reality is that matter does not just exist in three phases, and if you can allow your thinking to be expanded beyond that restrictive model, it will allow you to form a more complete picture of how matter is organized.  -- Jayron  32  12:41, 12 August 2011 (UTC)
 * Thanks for your answers, really helpful! — Preceding unsigned comment added by 90.28.53.74 (talk) 00:56, 13 August 2011 (UTC)

energy savers
are energy savers injurious to health? — Preceding unsigned comment added by 175.110.242.217 (talk) 23:46, 11 August 2011 (UTC)
 * What sort of 'energy saver' do you have in mind? There are several different things that term might refer to, and we don't have an article on any of them under that title. {The poster formerly known as 87.81.230.195} 90.197.66.65 (talk) 23:59, 11 August 2011 (UTC)
 * I'm going to take a wild stab in the dark and guess the OP means Compact fluorescent lamp. If that's the case, the health effects have a separate article Fluorescent lamps and health. But the short answer is no, CFLs are not particularly bad for you. Vespine (talk) 00:04, 12 August 2011 (UTC)


 * Well, my idea of energy saving is curling up in bed with a nice book and a lovely cup of hot chocolate. And that's a lot less potentially injurious than, say, skydiving. Myles325a (talk) 01:41, 12 August 2011 (UTC)