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Although this is a very silly question for us Canadians, I actually found a quote: "Studies in Canada have shown some cows have gone 50 to 60 days with snow as the sole water source without any adverse effects." However, it quite uncomfortable to take a shower in snow. --Zeizmic01:13, 1 May 2006 (UTC)[reply]
How are fullerene molecules formed? Is there a reaction mechanism process that creates them or is it something else. I am particularly interested in buckminsterfullerene and its formation. Thankyou. Vollsa01:05, 1 May 2006 (UTC)[reply]
Basically, you just zap graphite with lots of electricity (in a vacuum), which makes a messy mixture of all kinds of fullerenes and nanotubes. That's why the purification process is so important. —Keenan Pepper02:09, 1 May 2006 (UTC)[reply]
You can actually make some fullerenes and nanotubes, as well as excessive amounts of graphite by building an arc furnace in your backyard. Something pretty unsafe to the common man, arc furnaces involve running large current and voltage values through a phantom loop. Get some firebrick, and big pieces of copper that are about in diameter to regular copper piping, hook up a generator and set the copper rods having a centimeter or so of space between them, and run the current through! I probably shouldn't have said that. I hope nobody dies. Extremely dangerous. But that's how you make nanotubes and fullerenes, at home! Its probably illegal too, because of the "touch-the-wrong-place-and-you-die-effect." -- Mac Davis] ⌇☢ ญƛ.07:53, 1 May 2006 (UTC)[reply]
I have a friend who's banned from a nearby institution because of an "incident" involving nanotube generation and the apparent destruction of some lab equipment. He's been asked not to return, to use his words. Isopropyl22:17, 1 May 2006 (UTC)[reply]
I also remember reading some article about using a Laser on a sheet of very pure, very clean graphite. Seem to recall it being in Japan. It might've been related to making C70 instead of C60 though, it was 4 years ago at least. SanderJK23:32, 1 May 2006 (UTC)[reply]
Basically because of the principle that if you throw enough bombs into enough piles of bricks, one of them will sooner or later form a house :). Basically they're formed at random at high enough temperatures, when you have enough carbon atoms whizzing around, most of them will link up and form graphite, but a few of them will become various kinds of fullurenes and nanotubes. So the rest is a matter of filtering them out (as mentioned above). There is currently no good, ordered way to synthesize them. But you can safely say it's only matter of time before someone finds a catalyst, since there's a huge amount of people working on this. --BluePlatypus23:03, 6 May 2006 (UTC)[reply]
Mysterious line of skin
I dont now much but i am kind of concerned because i dont now what is wrong with me; my foreskin is retracted, but not past the head, and a line of skin runs from the base (on the underside) of my shaft to near the opening which connects the shaft to the skin. it is visible on the outside of the skin. Please help.
Doesn't that come with birth (the frenulum)? What do you mean you used to have one? AHHHHHHHH!! OMG WTF, the 4th time I read the above comment, I read that it snapped! Ahh! Owwwww. Owww!!
Anyway, to the question-poster: Does it stick out, three-dimensionally? How is it different from the surrounding? When did it appear? You're about 14-16? -- Mac Davis] ⌇☢ ญƛ.07:58, 1 May 2006 (UTC)[reply]
If this is something you're worried about, may I suggest you talk to your doctor? There is no need to be embarassed about asking, doctors have seen all manners of things, and s/he will be able to help you if there is something wrong, or put your mind at rest if there isn't. Remember, we're not doctors :) — QuantumEleven08:46, 1 May 2006 (UTC)[reply]
Seems that what you see is the penile raphe. The scrotum and foreskin are formed from tissue that in women would form the inner and outer labia. The ridge is where they have fused. Nothing unusual there, mate! Dr Zak11:30, 1 May 2006 (UTC)[reply]
Yah it's '3D', it just connects from by where the scrotom connects to the shaft and goes to near the tip of my penis. So nothing is bad about it though? I can live happy with it? i think it is a frenulum...
Yah, i google image searched it and it's a frenulum....
Pictures?
Are there any pictures on frog anatomy...or any other type of science-related subjects? Mostly people I know tend to be visual. Thanks!
Fundamentally asking 'why' about physical laws is not helpful. Physical laws are descriptions of the way things are: asking why things are the way they are is the realm of metaphysics. DJ Clayworth17:23, 2 May 2006 (UTC)[reply]
Naval Citrus Storage
How did the British Navy preserve lemons and limes that were used in preventing scurvy? A lemon may last several weeks if kept in ideal conditions, but it seems that the time between the fruit being plucked from the tree and the time it was delivered to the sailors would be a few months, or maybe even as long as half a year. The lime or lemon would have to be harvested, packaged, shipped, and stored before being finally served. Packing it in salt would just draw out all of the fruit's moisture. Does anyone have an answer?
--Sputnik
On a History Channel show, I remember that on one British naval exploration voyage to explore Canada, they used canned lemon juice, and had excessive amounts of it. But one of the downfalls of the mission leading to its death, was that the compounds in the lemon juice brokedown, and most of them ended up dying of scurvy. I seem to remember that they grew lemon and lime trees on the boat itself. -- Mac Davis] ⌇☢ ญƛ.10:59, 1 May 2006 (UTC)[reply]
...which creates another question. "Exploring Canada" and "growing citrus fruit": They'd have had fun growing lemon trees if this was one of the Northwest Passage expeditions! How the hell did they get things to grow in those temperatures? Grutness...wha?13:28, 1 May 2006 (UTC)[reply]
When I try to login in MSN Messenger, sometimes (most times) the window about the unread messages in my e-mail account pops up but the rotating icon keeps rotating, impeding me from viewing my contacts. Has anyone else experienced this problem? Does anyone know how to solve it? Thanks.
If you want to stick with MSN, go to Tools -> Options -> Alerts and Sounds and remove the checkmark beside "Display alerts when e-mail is received" Andrewjuren(talk)15:46, 1 May 2006 (UTC)[reply]
Relativity
Relativity often emphasize that the laws of physics for everyone are the same no matter what speed they are travelling at. Why is that?
The laws of physics are the same all over our universe( and probably all others if there are any more ). irrespective of what speed you or the observed object is travelling relative to each other. They are this way because if they were not the laws would not be universal.
In other words the universe would break down and implode or flash into non-exixtence, because the physical laws in zones with common borders would not be compatible. Some may say that the laws could be different if there were volumes of space containing nothing between different areas or universes.
This is also impossible for at least two reasons.
1. there can be no areas where 'nothing' exists ( neither time nor space) for the obvious reason that if there is no space there is no separation and
2. If there was something called space between the two areas then such entity would have its own border regions which must by definition come up against the formerly mentioned regions and therefore be in contact.
As you can see the speed of objects or entities does not have any real meaning in this context because
1.Even if the two objects were travelling say in opposite directions at the speed of light ( as in fact photons often do ) each would be travelling AT the speed of light relative to the other. They must by definition respond to the same laws of physics because even though travelling at light speed they would have at some time have been in the same area.
2.If they are travelling at different speeds, say one is 'stationary' and one travelling at 180,000 k p sec. in the opposite direction, then what happens ? If the laws were not the same we could not 'see' each other, obviously because we would not be using the same laws. If we did 'see' each other we would have to conclude that we were subject to the same laws. If we swapped places and we were then on the object travelling at 180,000 kps what would happen ? We would perceive that the other object was travelling away from us at that incredible speed and that we were stationary ( if we did not have any other reference point which was within our sphere of observation )
You can also ask the questions:
a) what happens when the two entities are travelling toward each other ?
b) Which one is moving ?
Very good question. it looks plausible, but (other than Wikipedia mirrors) gets virtually no google hits. I've sent it to Wikipedia:Articles for deletion where hopefully some people more in the know will be able to work out whether or not it's for real. Grutness...wha?13:37, 1 May 2006 (UTC)[reply]
i think people need to stop inveseting so much faith in the ridiculousness (sp?) of google.
i could be mistaken but i believe it's filtered by republican war machines! but like i said i could be wrong....now off to macdonalds! PSYCH! peace -jms
in gsm technology, we have MSC codes(represented by first five digits of the 10 digit cellular number).
what is the counterpart of this in the CDMA technology?
is it diffrent in various parts of the world?
if yes then , what is the trend in india?
Is it possible to use sextants or similar low-tech tools for Celestial_navigation in an activity like geocaching? The accuracy of many GPS receivers is about 3 metres. What would be the typical accuracy of using astronavigation techniques? Does it even come close to 3 or 10 metres or is it too fuzzy to use for geocaching? --Sonjaaa13:19, 1 May 2006 (UTC)[reply]
I'm certainly no expert, but I'd be extremely surprised if you could get closer than a couple of kilometres to absolute accuracy with a sextant alone. In the days when they were the principal form of navigation, they were used (a) in the open sea, where absolute accuracy was not necessary, (b) close to or on land, in which case triangulation using major points of reference provided an important secondary tool and would be able to provide far greater accuracy. I certainly wouldn't think you could use astronavigation alone for geocaching, though a combination of it and triangulation from landmarks might get you fairly close. Grutness...wha?13:46, 1 May 2006 (UTC)[reply]
While doing things the old way might be an interesting diversion for modern geocachers, the same problem faced polar explorers, particularly those hoping to be the first to either pole. A sextant is indeed much too crude, but celestial navigation is the only option - there's no maps (so no known landmarks against which to triangulate) and magnetic compasses are useless at such extreme latitudes (indeed, beyond the 80th parallel they're pointing in entirely the wrong way). Amundsen (at least, probably others) did use dead reckoning as a backup (a spiked wheel on one sled turned as it moved over the snow), but the irregularities and twistiness of the terrain make that only of moderate use. It's an interesting question to ask "who was the first person at a given pole" - how close does one have to be for it to count? Amundsen and Scott both took with them fairly bulky instruments (theodolites, I suppose) such to measure the precise location of the sun (remember also that they did their explorations in the antarctic summer, when the sun never sets, so there are no sunrise and sunset measurements to be had, and the stars are never visible). I imagine these were fitted with some form of tunable slit to allow the position of the sun to be precisely captured (when you get to the degree(sic) of accuracy needed, the apparent diameter of the sun will itself be an issue - so you'd need to measure the position of the left and right edges of the sun (hence the slit) and average the two). I believe (from my recollection of Roland Huntford's Last Place on Earth) that these observations (and the subsequent hour or so of calculations) were done only once per 24 hour period, except when they were very near the pole, when it was necessary to conduct them almost continually. Amundsen camped where he thought the pole was, but moved the following day (after extra detailed observations and calculations) showed it to be more than 1 km away. Even then, modern astronomers examining his logs and recalculating his position with more accurate tables think he was still about 1km off, and that two men in his party (when trekking from one camp to the other) probably came to about 300m of the actual geographical pole. And remember that Amundsen had a master's certificate and both Helmer Hanssen and Sverre Hassel mate's certificates, so a more experienced bunch of celestial navigators you'd not find. It's a remarkable feat of celestial navigation, but still too poor for geocaching, I think. -- Finlay McWalter | Talk14:57, 1 May 2006 (UTC)[reply]
Even if the stars were not visible, I suppose the Moon would still have been visible some of the time, and it could have helped them slightly. – b_jonas00:03, 2 May 2006 (UTC)[reply]
Torge, Wolfgang. Geodesy (3rd Edition ed.). {{cite book}}: |edition= has extra text (help) mentions the accuracy of some observational instruments. For stationary observation the Danjonprismastrolabe achieved a precision of ±0.05". For field measurement, transportable instruments mentioned are: prism astrolabes, zenith cameras (±0.5" or better) and the universal instrument (a theodolite with attachments for astronomic observations, ±0.1" to ±0.3".) All these instruments require a very accurate integrated time source, synchronized with International Atomic Time. EricR16:36, 1 May 2006 (UTC)[reply]
making map pictures for wikipedia?
I want to add an image of Leslieville to show the boundaries of the neighbourhood, can I use google maps or if not then what online mapping source can I legally use to make the image, showing all the streets and the boundaries?--Sonjaaa14:34, 1 May 2006 (UTC)[reply]
No, you can't use google maps in wikipedia, either directly (by including the image) or indirectly (by tracing over a google map) - the maps are copyrighted by Google and its partners, and certainly aren't compatible with the GFDL. See Wikipedia:WikiProject Maps for links to resources for drawing your own map; suffice it to say that it's hard. -- Finlay McWalter | Talk15:02, 1 May 2006 (UTC)[reply]
That's strange that tracing is not allowed (even from satellite view?). Does it mean that Google basically owns the shapes of streets in Toronto, for example?--Sonjaaa15:33, 1 May 2006 (UTC)[reply]
No, you could go out into the street with surveying equipment and measure it yourself, and that would be perfectly legal. But maps are certainly copyright, as are photographs (and a tracing, as a derivative work, is still the copyright of whomever took the original photo/survey). It's questionable if you could really get caught tracing a google map, but remember that the map projection is specific to Google, and mapmakers are notorious for deliberately introducing small errors into maps to catch copyists. Now, there are PD satellite and aerial photos, so you could either use those or trace them. Things are particuarly nice for the US, because NASA World Wind will retrieve free USGS topographic maps, landsat photos, and (for major US cities) detailed aerial photography. All of that stuff is public domain, and can be used in Wikipedia directly or as the basis for composites, diagrams, maps, etc. But for Canada all worldwind will give you is the Landsat imagery, which (at 15m I think) is much too chunky for street-level stuff. Natural Resources Canada has some information here, but I don't know how detailed their stuff gets. Urgh, on checking their page even that is non-commercial-use only, which still means it can't be used on Wikipedia. -- Finlay McWalter | Talk15:47, 1 May 2006 (UTC)[reply]
Ontario has digital base maps here [1] I just emailed them to check the public domain status, since I don't see anything on the web site. --Zeizmic15:48, 1 May 2006 (UTC)[reply]
One thing that can be done is to compile an approximate map using GPS data. Image:London Underground Zone 1.svg is one such (the underground map of London), which was compiled by wikipedians with handheld GPS units and some software to bold the whole thing together. An impressive piece of work, but still a lot of work. -- Finlay McWalter | Talk15:50, 1 May 2006 (UTC)[reply]
As the recent Dan Brown copyright case shows, if a copyright case comes to court the creator of the contested content will be asked to prove they really created what they say they did. It's quite reasonable for a court, at some future point, to ask "where did this map come from?" Google (well, their suppliers) can show they made their map, because they have the original survey notes of the surveyors. If you traced a map or satellite photo, you can't produce such notes. "How", you might ask, "would Google or anyone else become so suspicious so as to sue in this manner?". Firstly, Google don't own most of their mapping data - they buy rights from regional mapping agencies - and for many regions, only one company (often a division or agency of the government) has actually done the on-the-ground survey. Say, for example, if someone uploaded a street map of a city in the UK. Bar a very few places, that original data has only ever been mapped by the Ordinance Survey - so the very fact that the map is fairly accurate is enough to make the OS's flesh-eating lawyers suspicious. And secondly, as I noted above, cartographers often put little errors into maps - if the error shows up in your map, it's strong evidence you copied the map. And don't for a moment imagine the satellite images Google shows haven't been montaged, adjusted, and potentially tweaked in just the same manner. Anyway, it's a very bad mindset for a Wikipedia contributor to be in when they're thinking "how can I sneak in copyvio stuff and get away with it?" -- Finlay McWalter | Talk16:25, 1 May 2006 (UTC)[reply]
Does it mean that I can't use Google earth pictures in my website, even if I don't make any money out of it ? Say I use a high resolution map of a city and lable the streets etc and display it so that it is helpful for others to find their way around ? If i really want to do it, can I get google's permission ? How do I get it ? --Wikicheng18:26, 1 May 2006 (UTC)[reply]
I just got the standard answer back from the Ontario gov't: "These maps, and maps you make from them, are mine, mine only, and always mine!" There is no such thing as public domain in Canada, unless you are talking about a neato 1885 map of Ontario. --Zeizmic18:51, 1 May 2006 (UTC)[reply]
Copyright is copyright: "I don't make any money out of it is" absolutely no legal defence. Imagine if you duplicated Disney's latest DVD and gave away copies. Would you make money? No. Would Disney sue you for every penny you owned, and a lot you didn't? Sure would. Similarly "being helpful" isn't a defence for copyright theft. Maps cost millions and millions of dollars to make, so the people who make them are every bit as keen as Disney to stop theft. Please stop looking for loopholes, you are doing yourself no favours! If you want to license content from Google, start by sending them an e-mail; but since Google in turn license their maps from other people they might not be able to sublicense to you. However, many parts of the world are covered by people who will allow limited use of their maps, in return, perhaps for a credit, or at least allow you to link to a small part of the map. For example, http://www.streetmap.co.uk/linkto.htm explains how to link to their maps of the UK, while http://www.ordnancesurvey.co.uk/oswebsite/getamap/ allows you to download up to 10 UK maps for use on your web site free (subject to terms and conditions including a particular form of credit with a link back to their site. Notinasnaid18:58, 1 May 2006 (UTC)[reply]
Does the web site give you permission? If you aren't sure, but it seems to, please post the URL of the information in doubt. Notinasnaid20:04, 1 May 2006 (UTC)[reply]
Although this is depressing, throughout Canada, you will find the same thing. If you email them, you will get the 'crown' speech that I got. Only if they proudly splash 'public domain' on their web site (as the National Archives) are you in the clear. --Zeizmic01:50, 2 May 2006 (UTC)[reply]
I don't find it depressing. I'd rather the Ordnance Survey made its money by commercial licensing of the results of its work, rather than pay more taxes so they can give it away. Notinasnaid10:47, 2 May 2006 (UTC)[reply]
I thought I'd add a little more, since I've been reading the accounts of the Ordnance Survey. In 2004-5, it cost 105 million pounds to run the Ordnance Survey, but the total of government grants was 1 thousand pounds. All thanks to the wonder of copyright! By contrast, the United States Geological Survey (which admittedly does more than maps) has a government budget of $938 million. Notinasnaid22:28, 2 May 2006 (UTC)[reply]
Let me assure that being a wikipedian I wasn't planning to misuse the google map. I just thought that it would be useful to setup a website which would allow people to navigate thru a city easily. Definitely not looking for loopholes ! My apologies if I sounded that way. Well... I may write to google and see what they say. Thanks for all the info and help --Wikicheng12:08, 2 May 2006 (UTC)[reply]
Voltage Coversion with a small elecronic appliance
I live in the USA and am taking my USA Digital Canon Rebel XT to Europe this summer. Ordinarily I would take a voltage converter but the specs on the back of the battery charger say the "input" is 100V - 240V so I am thinking that other than the issue of incompatible prongs, I could theoretically use this charger without converting the voltage (just perhaps get an adapter so the USA prongs can fit into a European outlet). Doesanyone have any knowledge about the implications of the specs on the charger? Do you know anything about the Rebel's battery charger? (It is the CB-2LT charger).
You could just use a plug converter for the 50,000 different plugs in Europe. I would definitely use an external charger, since I hear they get power spikes when they change hamsters. --Zeizmic15:18, 1 May 2006 (UTC)[reply]
Zeizmic is quite clearly a complete bell end. Let me re-phrase that for you;
You could just use a plug converter for the 3 different plugs in Europe. I would definitely use an external charger, since I hear they get power spikes when america declares war on another innocent country. PhilcT+C16:45, 1 May 2006 (UTC)[reply]
Thank you for standing up for us, PhilC :). Just to be sure, make sure that your charger also takes 50-60 Hz current (US is 60Hz, Europe is 50Hz). If it's 110V-220V it almost certainly will, but you want to make sure. As for plus, your best bet is one of those 'universal' adapter plugs they often sell at airports (although they're not always cheap). Alternatively, which country are you going to? Take a look at Electrical plugs: Most of Europe uses a type C, except for the UK and Ireland, which use a type G. In Italy and Switzerland you'll still find some type L sockets, but most hotels will have converters in stock so you can use a type C. Hope this helps! — QuantumEleven13:06, 2 May 2006 (UTC)[reply]
Television set from USA to India
Hi
i have a used Toshiba television set from 1997 which has only Closed Captioning and no fancy features.
i plan to take it to India.
i understand that the US has NTSC colour television system while India has the PAL colour television system.
Is there a way that the television set would work in India?
[++ Any specific knowledge of duty at Indian Customs would be welcome too ++]
Regards
Babbu
See NTSC and PAL. As discussed here previously, if you try to watch a PAL program on an NTSC set, you will get a fuzzy gray image that rolls every few seconds. There are PAL-to-NTSC converters, but they cost far more than a new PAL television. All in all, you'd save a lot of money by leaving (or selling) the NTSC tv and buying a new PAL tv in India. --Kainaw(talk)16:27, 1 May 2006 (UTC)[reply]
Worse, as India has 230V mains and the US 110V, it'll probably burst into flames as soon as you plug it in (so you can't use it even with a US DVD player, unless you wasted more money on an expensive voltage-transformer). Anyway, surely the cost of shipping would cost more than the price of a new TV in india. -- Finlay McWalter | Talk16:33, 1 May 2006 (UTC)[reply]
Dear Kainaw and Finlay McWalter
Thank you very much for your prompt and informative replies and apt suggestions.
i will certainly do as you say.
The shipping for the TV would cost over $300.
Regards,
Babbu
Simple Carbohydrates in a Packet of Sugar
Hi there,
I was wondering how many carbs are in a packet of sugar. Or Even easier, how many grams of sugar are in a packet, because I have a carb count for 100 grams of sugar but I don't know by what to divide it.
Thanki
Why don't you look under the "nutritional information" of the packet and look. Looking at my bag of granulated sugar, per 100g of sugar = 100g carbohydrates; one serving (amount not specified) is 4g of carbohydrates. Kilo-Lima|(talk)16:51, 1 May 2006 (UTC)[reply]
That would knda mean one serving is 4g of sugar -- is this some sort of trick question? Sugar is 100% carb; that's kinda the whole point. --jpgordon∇∆∇∆01:05, 2 May 2006 (UTC)[reply]
I need to find information on army paying for my medical studies. I heard that the army pay for you university studies if you join the army for a short period. Does anyone know a good website to find information on this? I am looking for information for british universities.
Google is probably your best bet. I'd advise against speaking to recruiters as they're notorious for over-hyping military scholarship programs (at least that's the case here in the U.S.). Best, David Iberri (talk) 21:23, 1 May 2006 (UTC)[reply]
Stars n Universe
Since stars work out by Hydrogen fusion and at later stages Helium and then much heavier atoms as it begins to collapse, but where do atoms aobve the weight of iron come from, because only hydrogen was created in the big bang, so where do the heavier atoms come from since it becomes energy-wise unprofitable to fuse atomic nuclei beyond iron.
Also once a predominant amount of the nuclei have gone through whatever process is the answer to the question above, will stars cease to exist, or will there be fission stars, or what. Cheers PhilcT+C16:36, 1 May 2006 (UTC)[reply]
I couldn't really find anything about the fate of stars after large amounts of the matter in the universe make up atoms heavier than iron in Ultimate fate of the universe or wether fission stars are possible. Does anyone know the answer, or could point it out to me. PhilcT+C17:58, 1 May 2006 (UTC)[reply]
See uranium. It is a very plentiful material on Earth. It goes through natural fission on the Earth - enough to affect the core tempurature of Earth. So, if you define a "fission star" as something that floats around space and contains some material that goes through natural fission, then Earth is an example of a fission star. As for your assumption that Stars will eventually use up all the hydrogen in space, you are assuming that there is no source of hydrogen. Why can't there be fission going on all around space. There is certainly enough radioactivity to get things going. --Kainaw(talk)18:17, 1 May 2006 (UTC)[reply]
I think he is thinking of a more intense and larger reaction going on than simple, small, localized reactions taking place on a tiny rock. That's a good question—the possibility of a fission star—I'd day no. Because in what I've read, I've never heard it mentioned. -- Mac Davis] ⌇☢ ญƛ.20:51, 1 May 2006 (UTC)[reply]
I wouldn't of thought it was naturally possible after considering it for a while, for a star sized mass of such high concentrationns of heavy elements such as uranium to form. So although it is unlikely to ever occur, as a thought, would it be theoretically possible, and how would it differ from fusion stars (eg, nuclei created by fission tend to have huge half lives, whilst nuclei created by fusion have relativly minimal ones, so if it supernovad, would a fission star polute space or something) PhilcT+C17:56, 2 May 2006 (UTC)[reply]
As I understand it, the fuller cycle seems to be, and this is a laymans understanding only in outline:
Theres a huge amount of hydrogen in space. The mechanism for stellar formation and conversion for elements from fusion, from lighter to heavier, from hydrogen to to helium and up to around iron, is reasonably understood. After that point, usual stellar processes by means of atoms combining, cease to be net producers of energy and become net consumers, so heavier elements cannot form in that way.
As this happens, the star which has been burning hotter, cannot sustain its power output, and the immense pressures generated by this heat cannot counteract gravitational collapse. So (a sufficiently massive) star collapses somewhat, and sits there glowing as a dwarf star. Presumably it may become a nova for a time too.
A sufficiently large star has such a mass, that gravity itself can overcome the remaining pressures. The forces that prevent collapse above, are overcome, and the star may become a neutron star, or collapse and then explode as a supernova.
In this final collapse, forces other than nuclear fusion are at work, mostly driven by the immenses force of gravitational collapse. It is my understanding that this is the environment in which heavy elements beyond iron are formed and exploded out into the universe at large.
So in a nutshell, lighter elements are created by the fusion reaction of smaller atoms combining into more stable medium sized ones, and heavier atoms are created by gravitationally driven collapse. So ultimately, the energy given off by elements such as uranium, comes from gravitational energy which has been "used" to form unstable heavier elements that then in turn decay giving off energy themselves as they revert to more stable forms.
Hope this helps, and if it's roughly accurate add it to some appropriate article on creation of elements or stellar processes. As said, its my lay-understanding only, but I think its roughly ok as a broad non-technical answer. FT2 (Talk) 15:09, 2 May 2006 (UTC)[reply]
DNA synthesis techniques (also Protein synthesis)
Does there currently exist a technique which permits the synthesis (as opposed to the sequencing) of a specific desired strand of DNA or RNA of known sequence, presumably using its base nucleotides? If so, how does this work and what are the limitations of the technique? As this might be a lengthy answer, a very brief explanation and a reference for more data would be terrific.
(I am already familiar with PCR, and using and selecting an existing sequence/allele for amplification or expression in-vitro. I am curious about synthesizing very long strands or sequences which may not be found in nature.)
As a correlary, is there a simple, high-yield, automated process for protein synthesis from its amino acids? Especially for longer, more sophisticated proteins?
Don't bite the newcomers—his doesn't look like someone looking for us to do his homework; he's just looking for pointers. Worse, your answer is incorrect.
Short strands of DNA (up to a couple hundred of bases in length) are regularly synthesized for all kinds of purposes. These oligonucleotides (usually just called 'oligos') are often used as PCR primers. Google for 'DNA synthesizer' to find commercial equipment and information.
Since synthesizing really long strands of DNA artificially tends to be error-prone, you can sequentially stitch together shorter oligos using DNA ligases to build entire genes from scratch.
For proteins, a similar process can be used. (Different reagents and equipment, but similar concepts.) Protein synthesizers (again, Google for them for more info) can sequentially ligate amino acids to build an artificial protein. However, this works well only for relatively short sequences. 20 amino acid residues usually works fairly well; 30 is about the limit. Again, it is possible to ligate these chunks together, but it's more difficult than with DNA.
Trying to synthesize a larger protein in this way isn't – as far as I know – possible. Your synthesis and ligation yields get too low. Also, getting a large protein to fold properly usually requires chaperone proteins that won't be present in your system. TenOfAllTrades(talk) 17:52, 1 May 2006 (UTC)[reply]
Ten is correct. There is active debate in the synthetic biology community as to whether or not DNA synthesis should be regulated, as the sequences of many known human pathogens are available online. These include extremely infectious diseases that are otherwise difficult to acquire, such as smallpox or the previously extinct 1918 influenza virus. As the technology stands today, costs for synthesis hover at around one dollar per base pair, which is prohibitively expensive beyond a certain point. Worse yet, not every sequence can be successfully made (for a variety of reasons) which leads to enormous time sinks as orders come in, weeks are wasted trying to synthesize them, etc. Hope this helps! Isopropyl22:01, 1 May 2006 (UTC)[reply]
Thank you to the both of you who offered me a nudge in the right direction. Yes, I am a newcomer, I am also a "she", and I had a brainstorm the other night on overcoming some of the protein synthesis challenges to which you alluded. DNA synthesis seemed like a reasonably obvious extension of the problem. Your leads (and admonition for caution in terms of safety/socio-economic implications) are very helpful. Have a terrific day!
Ingredients of "parfum"
Recently i purchased a deo which states under the ingredients list the following "alcohol denat" & "parfum".
I read the comprehensive article with regard to "alcohol denat" in wikipedia site and all he ingredients used in making it, but was unable to find out the same with regard to "Parum" Please help me to get the ingredients used in making the same.
"Parfum" is French for "Perfume". It means "artificial scent". This is similar to food that lists "artificial flavors" in the ingredients. So, you won't find the specific ingredient used. --Kainaw(talk)18:42, 1 May 2006 (UTC)[reply]
thanks for the reply, but a small clarification, i read in an article that there are two kinds of alcohol used in cosmetics and perfumes (1) alcohol denat (2) alcohol parfum.
if parfum is french for perfume then what is alcohol parfum?. appreciate your views on this
"Alcohol perfume" is basically grain alcohol (190 proof). "Alchohol denat" is short for "denatured alcohol". A denatured alcohol is poisonous, which means that it falls outside of laws governing alcohol that you can drink. There are governmental laws and religious laws governing alcohol usage. By using denatured alcohol, perfumes get the benefit (the perfume evaporates faster) without the legal/religious hassles. --Kainaw(talk)20:39, 1 May 2006 (UTC)[reply]
Denaturated alcohol is not actually poisonous, at least not more so than ordinary alcohol. It is just undrinkable, usually through adding Bitrex or some similar substance which tastes horrific even in trace amounts. Chemistry lab ethanol can be quite toxic though, in particular the "dry" kinds (with concentrations above the water azeotrope at 96%). Those often contain drying agents like Bromobenzene, which react with water. For use as a solvent in things like Grignard reactions when you absolutely do not want any water present. --BluePlatypus22:55, 6 May 2006 (UTC)[reply]
magnetic north
If you travelled into space with a compass
which way would it point once you'd left
earths atmosphere??
The Earth's magnetic field extends well past the atmosphere. Magnetosphere. However if you got far enough away from the Earth other planet's or the Sun's magnetic fields would be where you compass would point to. -- Mac Davis] ⌇☢ ญƛ.20:47, 1 May 2006 (UTC)[reply]
BP suffix on medicines etc.
Why is it that some medicines have their name, for examples (this is made up) Magensium Hydrochoride BP. What does this stand for if anyone knows? Thank you
See benzoyl peroxide. It is a popular medicine for acne and teeth whitening. The initials "BP" commonly follow many acne medications to signify that benzoyl peroxide is the primary ingredient, such as Xerac BP. --Kainaw(talk)23:24, 1 May 2006 (UTC)[reply]
Except I have medicines where it seems unlikely to signify an ingredient. For example, in the ingredients list it will say "Hydrocortisone BP 1% m/m Also contains white paraffin." In this case, Notinasaid's meaning seems much more likely, and seems to match the example. If I ever see it following the name of a tooth whitener or acne treatment however, I shall be sure to remember benzoyl peroxide. Skittle01:39, 2 May 2006 (UTC)[reply]
BP does stand for British Pharmacopoeia. The comparable label in the US is USP, which stands for United States Pharmacopoeia and indicates that the product meets the specifications of the USP. This is normally used of older generic products (e.g., aspirin or Epsom salts) that you might consider "medicinal chemicals" rather than patented pharmaceuticals. alteripse05:11, 2 May 2006 (UTC)[reply]
You have two balls perfectly next to each other on a perfectly smooth slope. Both balls are of exactly the same composition. When you roll the balls at the same time down the slope, they should both travel at exactly the same rate.
Take the same situation, but this time make one of the balls hollow. Will the hollow ball be slower than the other because of friction from the air inside? Or for any other reason? Flea11021:00, 1 May 2006 (UTC)[reply]
My guess is the 'friction' from the air inside would be minimal, the hollow ball would be lighter than the solid ball. Since it has the same surface area as the solid one it would be slower due to air friction of the air OUTSIDE.
Okay, so you're familiar with the concept of inertia, right? An object at rest tends to stay at rest. The moment of inertia is another way to measure inertia, only around an axis with rotation. You'll find (from list of moments of inertia) that hollow spheres have a greater mass moment than solid spheres, and thus have a harder time "getting the ball rolling", as it were. Your solid sphere will roll down the ramp faster. Isopropyl22:10, 1 May 2006 (UTC)[reply]
True, for two spheres of the same mass but with the mass arranged differently within them. It occurs to me that Flea110 might be thinking about a case where the density of the material we're making the spheres out of is a constant, in which case it'll depend on how hollowed out it is. According to the back of my envelope, if the radius of the hollow region is more than 73.6% that of the total sphere then it'll have a lower moment of inertia than the solid sphere. --Bth09:00, 2 May 2006 (UTC)[reply]
I did not believe Isopropyl at first either, but looking at the energy of the spheres at the top and bottom of the ramp: If the angular mass is in the form kmr² and the translational velocity is related to the angular velocity by v=2πrω, then the mass and radius of the sphere cancel out. EricR15:58, 2 May 2006 (UTC)[reply]
Simple test for sugar?
Is there a simple test for the presence of sugar? I've been buying Nesquik made with Neutrisweet for years, but I bought some that has the appearance, texture, and disolving qualities of the sugared kind. I wrote tothe company about this, but they didn't understand what I was talking about. So is there a simple household test for the presence of sugar? Bubba73(talk), 21:18, 1 May 2006 (UTC)[reply]
Not helpful. If you think a difference between the two types of nesquik include a reducing sugar such as fructose (look on the labels) you could test using Benedict's solution if you can get any. That article lists common sugars it detects. However, it's more likely you need a test for sucrose, and I can't remember or find one. I'll have another look. Meanwhile, just get clear and firm with Nestle. You bought a product labeled as sugar free, but you suspect it is the version with sugar. They may have a packing or labelling problem. Suggest you are diabetic :-) Skittle22:58, 1 May 2006 (UTC)[reply]
I am, that's why I use the suger-free version. I think it is probably labelwd or packaged in error. I wrote back to them today. Bubba73(talk), 23:09, 1 May 2006 (UTC)[reply]
Okay. If the difference in ingredients is sucrose, and you can get your hands on benedict's solution and fairly weak hydrochloric acid, then it should give a negative result to benedicts solution at first, but a positive result if it's been boiled with hydrochloric acid for a few minutes. However, since you are in America, there's a good chance that the sugary version is made using high fructose corn syrup, so it will test positive using Benedict's. If you buy some more sugar-free stuff, with a different batch number, and look at the label finding no reducing sugars, and test it with Benedict's and find it negative, then there you go. However, much better to complain effectively, send your sample and get reimbursed. In my experience, food companies (especially big ones like Nestle) will give you the benefit of the doubt quite quickly and try to sweeten you up with vouchers. They will also want to check your product so they know whether they need to issue a statement and a recall. Skittle23:13, 1 May 2006 (UTC)[reply]
Actually not. I emailed them at first, and I got this reply on April 19: "Thank you for contacting Nestlé on the Internet. Questions and comments from our consumers are always welcome!... We reviewed your email and will be responding to your request via regular mail. You can look forward to receiving a written response from us within 7-10 business days.". Today I get the letter in the mail (and it was from the same person). Bubba73(talk), 23:48, 1 May 2006 (UTC)[reply]
Identifying a flora or fungi from SE Arizona
I have uploaded a photo of what I thought was perhaps a mushroom of sorts. I have since looked through a catalog of fungi photos and saw none similar. The fellow in the photo felt smooth, cool, and mushroom-like to the touch. It grew near or in decaying organic material in the shade. Does anyone know what it is?
Thanks for your attention. This is a great service. I used a hyperlink rather than the Image: in brackets because I didn't know if it was acceptable to actually display an image on this page. Hope that is okay.
I don't think it's a fungus, since they look like they have some sort of flowering apperatus at the top? I'm not sure. What I am sure about, though, is how to link to an image without displaying it. You'd use [[:Image:Unknown_SE_AZ_April_29_2006.jpg]] to produce Image:Unknown_SE_AZ_April_29_2006.jpg. Note the leading colon. Good luck with twenty questions! Isopropyl21:50, 1 May 2006 (UTC)[reply]
In case anyone is curious, from the description, it was a saprophyte of some sort, and just did a Google image search for saprophyte. Luckily, there aren't all that many, and most don't look anything like the cancer-root. Wonder why it's called that? --jpgordon∇∆∇∆02:08, 3 May 2006 (UTC)[reply]
Perhaps because it is a root parasite (which accounts for the unusual color -- lack of chlorophyll). This site says they are invariably found among oak trees at least in Illinois (there were oaks in the area where the photo was taken.) Also curious is the common name of the family it apparently belongs to, "Broomrape." --Bad carpet21:57, 3 May 2006 (UTC)[reply]
Trying to find old (1988-1992 range) DOS computer game.
Hi all. I'm trying to remember the name of a DOS - CGA computer game I played back somewhere around 1988 to 1992, I forget the exact name of it.
It was called something *like* Starflight I think, but I found that one on the underdogs, and it's not it. It was similar in that it was a space game. You had a crew of 5 (or is it 6?) on your ship, and you had skills such as tactics etc for each person to go up in. On occasion you would land on a planet and go inside a structure. Inside the structure you would see the action in front of you, but then overlaid on that would be a small HUD-type display with the walls and such in blue. Your 6 crewmembers would be behind you in blue circles on the HUD as well, and then unknowns would appear as red circles. You could get weapons like laser cutlass, some kind of mace, but also some projectile weapons. One of the worlds you landed on had (3?) large towers (like 500+ stories), which were all "populated", but you were only interested in one particular area of one of them. Anyways, that's most of what I can remember. If someone wants some more details, or has questions, post and I'll try to remember some more. Thanks in advance. Aaronw22:50, 1 May 2006 (UTC)[reply]
May 2
Digital Video Recording Systems
on a digital cmara what is the Diffrence between the NTSC and the PAL video recording systems... is one better than the outher for taking videos?
Have you browsed the articles on NTSC and PAL? One thing you really need to take into consideration: if you record something in PAL, it won't play back properly on an NTSC-only VCR, and vice versa. If you're in the US (and I assume you are), NTSC is the standard and I'd say it's best you stick with that. Confusing Manifestation04:17, 2 May 2006 (UTC)[reply]
Microevolution & Macroevolution
I've heard some Christians and creationists claim that microevolution and macroevolution are separate and distinct from each other.They claim that all examples of observed evolution are of microevolution and that 'small changes do not imply large changes'.They also claim that there is a genetic barrier stopping organisms from evolving so far as to cross the species border.Are those claims true?
Long answer short: No. But reading the article is good.
Cockroaches surviving nuclear explosions?
Sorry if this is a kind of stupid question. Is it really true that cockroaches have survived nuclear explosions? I've heard people joke that cockroaches will be the only things still around after we all nuke each other to death, but I was wondering if that was really true. I already checked the page on cockroaches and several pages about nuclear weapons, and didn't find this information anywhere. I did see that they could survive high levels of radiation, but would they survive the amount of radiation in a nuclear bomb?
I am vary competent in basic and decent at C programming languages. A fellow robot enthusiast had suggested I switch to PSOC programmable system for my robotic uses.. had any one else had any experiences with PSOC?? is it worth the switch?? SumoBotMaker04:40, 2 May 2006 (UTC)[reply]
Recommend a chemistry text!
Hi all,
I'm looking for a good first-year-undergrad level chem textbook (or two, if it's impossible to get one that covers both organic and inorganic). My formal chemistry education goes up to A-level (about eight years ago), though I've done QM-of-the-hydrogen-atom what feels like a hundred times since. I'm looking to freshen up and slightly deepen my knowledge. Any recommendations? (Easily available in the UK is a bonus but not essential thanks to Amazon etc.) --Bth07:51, 2 May 2006 (UTC)[reply]
I can recommend John McMurry Organic textbooks, if you get older editions (not that much difference) ago via amazon used they're quite cheap. (Though postage might be a killer) The books in general give a very good basis for organic chemistry. Unfortunately, it does not cover inorganic chemistry, i'm not sure what to recommend (I was taught inorganic using Shriver & Atkins, but that book is not so straightforward). SanderJK08:50, 2 May 2006 (UTC)[reply]
i have a habit of chewing the skin near my nails.its like i cant think without chewing my skin.whats happening to me?
As per the disclaimer at the top of the page, you should speak to a medical professional if you're really worried about this. But nail biting (which this is considered a form of IIRC) isn't uncommon at all (the article contains both statistics on the prevalence and information on treatment).
Does all chemical reaction need an activation energy? If nuclear reactions need an activitation energy, what's the activitation energy for nuclear fusion? I mean what activates the hydrogen to collide and create and helium?
Yeah, nuclear fusion's the place to go, though I just want to correct another seeming misconception in the question: that "hydrogen" fuses to helium. Normal boring single-proton hydrogen doesn't fuse directly to form helium -- fusion experiments on Earth tend to use deuterium, tritium or helium 3 as fuel. In stars, the pp chain or CNO cycle are involved (in which some of the protons are converted to neutrons).
Just as an example, For a deuterium-tritium reaction the necessary energy is roughly 100 keV (about 1.6 x 10-14 J, tiny in everyday terms but huge compared to the equivalent for chemical reactions because the distances involved in nuclear reactions are so much smaller).
The energy needed can be provided by high temperatures and pressures (in stars and fusion bombs) or by various acceleration methods (in fusion experiments). --Bth11:39, 2 May 2006 (UTC)[reply]
Physics
Coloumbs law gives us force of attraction between two particles(charged).Does that include their masses as well?
How about if a massless particle (gravitron)were subjected to this postulate?
I'm not sure what you mean by "bigger effect". For the same charge, you'd get a greater acceleration for a less massive particle, simply by . I can't remember any massless charged particles either (the W bosons are charged, but also massive), but since massless particles are constrained to move at lightspeed, you'd have to treat any interaction properly using QED. Which would be hard.
To go back to the other question: in general, you could get a correction for the gravitational force simply by adding together the Coulomb and Newton laws, but the correction would be tiny. Consider the fact that atoms are held together by electrical forces and are very small indeed -- gravity is so weak that an atom held together solely by gravity would have a size on about the same scale as the universe. Gravity dominates on large scales simply because on large enough scales the positive and negative charges cancel out, whereas gravity is always attractive. --Bth11:46, 2 May 2006 (UTC)[reply]
Can nuclear power save the planet?
I live in the UK and here the debate about nuclear power seems to have entered a new era, with many people who would normally consider themselves "green" warming to the idea of nuclear, I suppose as a lesser of two evils. Meanwhile renewbles seem ever more remote as a possibility.
I would be interested to hear personal viewpoints on this from around the world. To phrase it as a question: Can nuclear power save the planet?
I'm in the UK and am fairly strongly pro-nuclear for the reasons you outline (incidentally, a leading proponent of this POV is James Lovelock, the Gaia hypothesis chap), though I have heard arguments that the extraction of nuclear fuel creates almost as much greenhouse emission as simple burning of an equivalent amount of fossil fuel, which would change the calculus.
I get very annoyed by many renewables advocates because so many of them who are pro in theory suddenly become anti in practice when someone wants to erect a wind farm within a sightline from their house. Terrible nimbyism. More general, the technology doesn't seem to quite be ready and AFAICS we need some sort of stopgap for another generation or so, either nuclear or carbon-sequestered fossil fuels. (From the security of supply POV, I'd choose nuclear.) Of course, the missing part of the equation is reducing the demand for power, at which we do an absolutely appalling job.
Having used your question to have a vent, I shall turn round and note that the reference desk isn't really for opinion polls. --Bth11:38, 2 May 2006 (UTC)[reply]
When using "nuclear power" and "renewable power" in the same argument, keep in mind that nuclear power is a renewable power. Assuming that humans figure out how to fuse the nuclear waste back together, nuclear power will become twin fusion/fission reactors. Because fission reactions tend to create very nasty explosions right now, many refer to nuclear power as a non-renewable resource without adding the clarifier right now. Then, the smarter ones add that if it were possible to recombine all the pollution from a standard automobile, you'd get gasoline and it would be a renewable resource. The catch is that nobody is working to do that. Fission reactors are being worked on all over the world. --Kainaw(talk)13:22, 2 May 2006 (UTC)[reply]
I don't beleive anyone is working on using nuclear waste as a fusion source - fusion power research concentrates on tritium and you would require more energy to reform the uranium than it would produce decaying, so you wouldn't gain any power by the process. And processes already exist to "make" gasoline - they are just not economically advantageous - see Alternative means of producing oil section of Petroleum. Rmhermen13:45, 2 May 2006 (UTC)[reply]
(after edit conflict) Erm, Kainaw...? With all due respect, that's completely wrong. Fusing the products of uranium fission back together to create uranium must take more energy than was gained from the original split of uranium (by the second law of thermodynamics), so you would be using (far) more energy than you produce. The same goes for 'putting back together' all the pollution from an automobile (not to mention the difficulties in collecting it all!). What you are describing is a perpetuum mobile, they do not exist.
Nuclear energy is a definite non-renewable energy source, because once we have used all the uranium on Earth, there isn't any more. It could be argued that coal, oil and gas are ultra-long-term renewables, as they were formed by organic matter compressed at high temperatures for millions of years - so, if we wait long enough (the aforementioned millions of years) the supplies will replenish. But that's only a technicality - we don't have millions of years to wait, and in any case we're using them up hundreds of thousands of times faster than they are produced naturally. So they are effectively non-renewable. — QuantumEleven13:51, 2 May 2006 (UTC)[reply]
If the question had been about "uranium power", I would not stated that it is renewable. However, the question was about "nuclear power". Waste from uranium fission plants is fusable. Therefore, it may be used is a fussion reactor. The waste from the fussion of uranium waste (which I never claimed would be uranium) will most likely be a viable fuel for a fission reaction. This cycle may be repeated until something unusable, such as radioactive carbon, is created. With the technology to rid ourselves of nuclear waste, we will certainly learn to create better reactors and have nuclear fusion/fission of common elements (how about water?). So, "nuclear power" is renewable. But, "uranium power" is not. --Kainaw(talk)14:49, 2 May 2006 (UTC)[reply]
By law of conservation of energy the reverse of a process that releases energy recquires an equal amount of energy. You can only fuse atomes up to iron, and only break them down to iron, so in either way you can only end up with, at best iron. Which is not a viable fuel for any nuclear reactor. PhilcT+C20:50, 2 May 2006 (UTC)[reply]
That's not how it works, as far as I understand it. A uranium reactor uses uranium and splits it (fission), releasing energy. The resulting elements are (by definition) lighter than uranium, ie further up the periodic table. If these products are heavier than iron (which most of them are, if I remember my nuclear physics correctly), they may undergo fission again to produce some more energy, although you won't get much out of them - but you can not fuse them together again to produce uranium, because any fusion reaction which produces an element heavier than iron is endothermic. If you get some light elements in your fission waste, yes, these can be fused, but again only up to iron if you want an exothermic reaction - and fusing anything other than the first half a dozen elements in the periodic table is nearly futile, the amount of energy you get out of the reaction is minuscule.
You may have been thinking of nuclear reprocessing, where radioactive waste from nuclear reactors is processed to remove any unfissioned Uranium so it can be used again - but that's a whole different story, for obvious reasons. We have an article on the nuclear fuel cycle which explains everything in far greater detail. Facit: Nuclear power (all varieties) is non-renewable, because the reactions involved to regenerate the fuel used do not occur naturally on Earth (Uranium and other trans-iron elements are only formed in supernovae). So: non-renewable. — QuantumEleven
There is a lot of nuclear reprocessing going on, but that isn't what I was talking about. I was referring to fission of nuclear waste - more commonly referred to as "actinide-burning power plants". Actinide fusion has been done in the small-scale. The large-scale goal is to pair up an actinide fusion plant with each uranium fission plant. Also - please do not continue claiming that I stated "nuclear waste will be fused to make uranium". I never made any such claim. The comment about recombining gasoline is not mine. It should be clear that I was repeating comments from anti-nuclear power people that I do not believe. --Kainaw(talk)17:21, 2 May 2006 (UTC)[reply]
That's still nonsense, sorry. Uraniumis an actinide. There's a certain amount of "missing" nuclear binding energy that everything except iron has. This energy is negative, so by converting things to something which is closer (in an approximate sense) to iron, they get more negative energy and you get some energy out. But there's a single chart here; going down it gets you some energy (e.g., fissioning plutonium in a breeder reactor or fusing hydrogen in the sun), and if you like you can spend energy to go back up (which may be fissioning calcium or constructing gold from silver and germanium or so, although the latter may not be practically doable). There is literally no way to make any sort of useful "cycle" on the chart. Perhaps you can reburn the waste from one reaction -- perhaps even in the other direction, if you split big atoms into several small ones -- but it's still a one-way street, and it's entirely nonrenewable (on our time scales). --Tardis18:51, 2 May 2006 (UTC)[reply]
You can believe it is nonsense. Since it isn't working yet, it may very well be nonsense. Just know what you are claiming is nonsense first by going to google and typing in "actinide fusion" to see what I am referring to. It is not fusing some nuclear waste to make some tasty uranium. --Kainaw(talk)19:34, 2 May 2006 (UTC)[reply]
I did that search (without quotes, since with quotes gave results that seemed irrelevant) and saw that the proposal was to use the neutrons generated by power-producing fusion to break apart actinide atoms. This would release a little more energy, although perhaps not as much as building a more efficient reactor that didn't bother with it, and would clean up some nasty radioactive junk that has no other use. Some authors seem to think it could be used to generate plutonium from common 238U, which would be useful for more fission power production. So it's not a bad idea, but it has nothing to do with creating a "loop" of fission and fusion; there are actinides, and there is fusion, but the actinides are undergoing unsurprising fission and the hydrogen is undergoing unsurprising fusion. Hope that helps. --Tardis22:07, 6 May 2006 (UTC)[reply]
I don't believe nuclear is a long run solution because just like petroleum, it's limited. Uranium and other minerals are not unlimited. However, I have to accept that it is a temporary measure and favorable vis-a-vis fossil fuel. Until renewables (minus dams) increase in efficiency and/or become relatively cheap/comparable to other source of energy, nuclear might be of help. There's an article about nuclear power in last April edition of National Geographic with comparison of carbon emission. IIRC in some other article some time ago in Nat'l Geo too, a cost comparison were made between all major source of nuclear, including solar and gangs vs nuclear, coal, crude.
All this however pertains to solving our energy crisis. I don't know about saving the world though. What do you mean by saving the world anyway? __earth(Talk)13:52, 2 May 2006 (UTC)[reply]
Thanks to everyone who responded! I guess I was aware that I wasn't using the Desk as intended, but I couldn't help myself. Opinion-based questions seem to get extremely interesting and intelligent responses here (flattery will get you anywhere). Is there anywhere on Wikipedia where you can hold structured debates? I mean the articles tend to sketch both sides of an argument due to the NPOV policy without letting either side really vent, while Talk Pages tend to get hung up on details. Anyway, thanks again.
While I agree that questions like yours do generate interesting responses, I would have to say that Wikipedia is not the place for debates - it's an encyclopedia, and we try and write the best, most impartial and complete articles we can on a given subject. You could try Usenet, or one of the countless forums debating topical issues (I can't think of any on nuclear power offhand, but there have to be many, many out there).
One point - while nuclear is non-renewable, the supply of potentially fissionable materials is pretty large (aside from breeder reactors, there is also the thorium fuel cycle; and thorium is available in massive quantities. Furthermore, increasing the price of uranium wouldn't affect the cost of nuclear power very much (because most of the cost is in building the plant itself). So much lower grade (and thus expensive to mine, but much more abundant) ores can be used; in the longer term even uranium extracted from seawater might become economically viable, and the supply of that is virtually unlimited. --Robert Merkel15:32, 2 May 2006 (UTC)[reply]
Additionally if one factored in the amount of weapons-grade uranium which could be downblended for power production there is already quite a lot of uranium sitting around, out of the ground, with nowhere to go. If one allows reprocessing of plutonium fuel (done in some countries, banned in the US), then one could also get some more bang for the buck. In the end I don't think there will ever be a single technological solution to "save the planet," but ruling nuclear energy out of the possible ways to generate power is just foolish. There are hazards, there are limitations, there are issues, but the same is true with all forms of power generation, and is true in spades with coal and oil. --Fastfission20:55, 2 May 2006 (UTC)[reply]
Evolution-oriented educational software
I'm wondering if anyone knows of any good software or games that focus on teaching evolution. Currently, the only title I know is SimLife. Anyone have any ideas? Thanks! — Asbestos | Talk (RFC)16:07, 2 May 2006 (UTC)[reply]
Richard Dawkins used to have a software program which allowed you to simulate evolution, but I doubt it runs on any modern PCs. This page has some links regarding it and some other similar software, but most of the links are totally dead. SimEarth was another Sim game which had a lot to do with evolution (via ecology). I always thought Oregon Trail had some aspects of natural selection involved in it... --Fastfission21:04, 2 May 2006 (UTC)[reply]
If someone is in a boat in the 1500s & the wind is blowing WEST, how can they go EAST, assuming there is no current?? Obviously they were able to, otherwise one would be at the mercy of the wind when sailing. 199.201.168.10016:35, 2 May 2006 (UTC)[reply]
Actually, if the wind is blowing straight west, it is impossible to travel straight east by windpower alone. Rather, a boat must keep zig-zagging accross the direction they want to travel in. Also, since you're speaking of the sixteenth century, I assume that you're asking about square rig sails. These do far worse when travelling upwind, although on warships one might see sails in many orientations, to try and sail in any direction. Typically, though, such ships make use of trade winds, which blow predictably, and so can be used to go where you want to go. — Asbestos | Talk (RFC)17:08, 2 May 2006 (UTC)[reply]
Hello,
I have been trying to get the flowchart for the manufacture of DDT(Dichlorodiphenyltrichloroethane)for sometime now but i've not been successful.Can anyone please help me out.I will be very greatful if anyone can get the diagram for me.
Thanks.
Have you looked at our article DDT (which, I admit, does not contain instructions for it's manufacture). Why would you like to make this product? It is available in stores at >90% purity! Andrewjuren(talk)19:36, 2 May 2006 (UTC)[reply]
Krebs cycle
What are the names of the vitamins that play a significant role as coenzymes in the Krebs cycle?
How many Joules of energy would be procured by a wire 1 metre away from a single iron dipole in a magnetic iron lattice (not counting other atoms in lattice) at 20oC (293.83K)? Thanks *Max*20:43, 2 May 2006 (UTC).[reply]
Acording to my Physics book all radioactive substances have a half life during which half of them decay. This means( according to my book) the substance should never decay entirly.
What happens then when 1/2 of the no. of atoms includes a decimal or is smaller than one?
For example, 1,000,000,000 atoms with a half-life of 10 seconds. After 100 seconds this should decay to 975,562.5 atoms. Is this posible? If it continues (including Decimals) after 300 seconds (5 mins.) it will become 0.9313 atoms, Again is this Posible? I know an Atom can be broken into smaller particles but can it go like that?
Thanks.
The expected number of decaying particles calculated in this way is an average. Most of the time the actual number of particles to decay will be fairly close to the predicted value from the half-life, but if only a few are expected to decay the actual result will be very different. In the example where the expected value is 0.9313, probably the most likely number of atoms decayed in that time is 1, but in specific cases it may be that 0, 2, or more may decay. The actual number of atoms that have decayed must always be an integer. -- SCZenz21:24, 2 May 2006 (UTC)[reply]
A good analogy to understand this principle is to imagine you have "radioactive coins". These coins are radioactive if they are tails up and not radioactive if they are heads up. So, you start with a bunch of coins that are all tails up. You flip them. About half of them will end up heads up (decayed) and half will land tails up (not decayed). The half-life of your radioactive coins is one flip. Now, on the next turn, you only flip the coins that are still tails up. Again, about half of those will decay. Once you reach a small number, you will realize that not exactly half of the coins will land heads up (especially if there are an odd number of coins) and that the result is entirely probablistic and not deterministic. To learn more, see our articles on Radioactive decay, Radiation, and the Poisson process (which shows the mathematical model of random radioactive decay). Andrewjuren(talk)21:38, 2 May 2006 (UTC)[reply]
This reminds me of the impossibility of having the mythical 2.4 children. Sure, you could chop a kid in half, but that's not really the point. Melchoir21:43, 2 May 2006 (UTC)[reply]
Well, but keep in mind that the number of atoms that have decayed, at a given point in time, is not necessarily well-defined, until you make an observation and collapse the wavefunction. Some atoms may be in a quantum superposition of decayed and non-decayed states. What exactly this means, or in what sense it corresponds to "reality", depends a lot on the interpretation of quantum mechanics. --Trovatore22:05, 2 May 2006 (UTC)[reply]
The statistical interpretation of half-lives does not depend on this kind of argument. It is perfectly possible to measure and record exactly how many decays have occured, and the problem asked above is still valid. -- SCZenz23:52, 2 May 2006 (UTC)[reply]
Well, the statistical interpretation does make the number of decayed particles approximately observable, when there are a lot. It's never exactly observable. Furthermore, the original poster asked about when there was one atom left, a state in which the statistical approximation does not hold, and Trovatore's comment is relevant. -lethetalk+14:34, 3 May 2006 (UTC)[reply]
Only in a general sense, that half-life is a bit of a simplifaction. You can't have a partially decayed atom; wither it's one element or another. --Scienda07:11, 3 May 2006 (UTC)[reply]
Chlorine
I was just wondering who discovered chlorine, and how it was discovered.
Would it be easier or more efficent for a plane to use a anamontronic wing-like aviation s ystem rather than using fixed wings? Would it be more fuel efficent if a giant plane were designed with big wings that moved similar to a giant hawk? And how would I go about getting a patent for this? Lord Westfall22:32, 2 May 2006 (UTC)[reply]
I have a friend who wanted me to ask do those pills that claim to make your cock bigger actually work? My friend asked me, but I don't know what to tell him. So do those pills actually work? If so, which ones? My friend really wants to know. Lord Westfall22:37, 2 May 2006 (UTC)[reply]
To play counterpart to Melchoir: Why did your friend ask you? Did he suspect that you had needed to use a variety of these in the past? If so, why would he know that? --Tardis22:51, 2 May 2006 (UTC)[reply]
Also read human penis size. The evidence that women actually prefer exceptionally large penises is pretty scanty. And, on the basis you were seriously asking, Melchoir and Tardis are having a bit of a giggle at your expense. Penis enlargement scams are one of the earliest forms of snake oilscam in existence. --Robert Merkel22:55, 2 May 2006 (UTC)[reply]
Well my friend doesnt want to have an exceptionally large penis, he would be happy with 6-7 inches as opposed to the slightly below average size he may currently have. If those pills are a scam, what options does he have? Lord Westfall23:10, 2 May 2006 (UTC)[reply]
Nothing good. All enlargement techniques (various types of surgery, fat injection) result in a loss of penis function. --Serie00:17, 3 May 2006 (UTC)[reply]
The organ between his ears, and how he uses it, will probably make a far greater difference to how enjoyable he and his sexual partner find their lovemaking is than the organ between his legs. Buying a sex manual or learning massage (for instance) would probably be a much better investment (and considerably cheaper)... --Robert Merkel05:12, 3 May 2006 (UTC)[reply]
Note: The "pills to enlarge your penis" are not pills "to enlarge" your penis. That is what the commercials appear to be saying, but if you look at the fine print, they are herbal remedies for erectile dysfunction. You could rationalize that to mean that they enlarge the penis - but not in the way that most people would think. --Kainaw(talk)12:54, 3 May 2006 (UTC)[reply]
Wiki is pretty much anonymous anyway, so no point in the old "my friend was wondering" explanation...we don't know who you are so why bother? Loomis5101:39, 5 May 2006 (UTC)[reply]
Staphylococcal infections
Staphylococci (including S. aureus and S. epidermidis) are known to migrate along medical devices such as plastic intravenous catheters. However, I believe they lack a flagellum, pilus, or other appendage for movement. Do they migrate along the catheter simply by dividing? Thank you very much.
Does anyone know what percentage of smokers actually develop some form of lung/throat/mouth cancer at some point in their lives? I'd be interested in seeing the statisics compared to the same kinds of cancer in non-smokers. I've had a look on the web but it's very difficult to wade through all the pro/anti-smoking propaganda. Anyone have a straight answer? Cheers. --Kurt Shaped Box23:48, 2 May 2006 (UTC)[reply]
80-90% of all lung cancer patients are smokers. I'll try to do a rought estamate of the percentage. If 154,000 (estimated) patients were diagnosed with lung cancer in 2002, and about 85% of them were smokers (let's say), that means about 130,000 smokers worldwide were diagnosed with lung cancer. About 45 million adults just in the US smoked cigarettes in 2004 (I know the years don't match, but this is just an estimate). You should get the idea that a very small percentage (<1%) are actually diagnosed with lung cancer, but that doesn't include other illnesses, and is no excuse to smoke anyway! —Mets501talk00:22, 3 May 2006 (UTC)[reply]
User:Mets501's number is the number diagnosed in a given year. Expand that to the lifetime of a smoker and you get a figure much closer to Rick's 1 in 8. Rmhermen14:01, 3 May 2006 (UTC)[reply]
i have read over the answers to the previous question regarding this topic and realised that it was a pretty straight forward example and would like to rephrase it to more smaller quantities:
Q: What is the simplest way to dilute 1M Hydrochloric acid down to just 250ml of 0.1M Hydrochloric acid? are there any specific calculations that need to be carried out?
thanks in advance!
A: You need to find out how many moles of HCl you will need to have in 250ml of water in order to have a molarity of 0.1M. Remember, molarity is moles of solute over liters of solution. --Chris00:48, 3 May 2006 (UTC)[reply]
Using
we have
where
and x is liters of 1.0 M aqueous HCl in 0.250 liters of total solution. So your cocktail would be 0.025 L of 1.0 M aqueous HCl in 0.225 L of H2O. Isopropyl01:34, 3 May 2006 (UTC)[reply]
Mystery Fish
This will probably seem less than mysterious to anyone with a vague knowledge of fish, but unfortunately there are lots and lots and lots and I don't know where to start looking, so... can anyone identify our little friend here so he can find some appropriate articles? Thanks :) Mystery fish (at the bottom) Yummifruitbat02:24, 3 May 2006 (UTC)[reply]
Thanks, Ginkgo100. I think this was a species from the Pacific coast of North America so I've spent a while googling for a likeness but haven't had much joy. I'll try emailing the aquarium. 'Goby' was right on the tip of my tongue/fingers but I couldn't quite get there and kept thinking of 'Dory' instead... when you replied a little lightbulb went on :)
Which side do you dress?
How much of the following is true:
A man's penis tends to hang to one side. With this in mind, tailors ask clients "which side do you dress". The majority of men "dress to the left".
I can't find it on Wikipedia, nor on Snopes. If it (or part of it) is true, what factors would influence it?
This would presumably be a cultural things. Maybe in some places (I've never heard of any) tailors ask for whatever reason. Maybe in other places tailors might face lawsuits. As for the actual right-left tendancy, if it isn't random then there's bound to be someone, especially on the Internet, who's researched it. Peter Grey04:24, 3 May 2006 (UTC)[reply]
Most tailors cop a feel, or else they can tell very easily while they are down there hungrily studying your junk.
I recently read an article by a doctor, in response to a question from a reader that his penis was oriented towards the left. The doctor had mentioned that most of the men have this feature. He even mentioned that the crotch of the trousers are stitched sligtly to the left side to accomodate this. But I have never had a tailor ask me this neither did I find any left orientation in the ready-made trousers -- Wikicheng06:14, 3 May 2006 (UTC)[reply]
This goes back to the days when men's trousers were a lot closer fitting than they are today. The crutch of the trousers would come right up tight against the scrotum, which needed to be positioned on one side or the other to avoid it being uncomfortably divided, with one testicle hanging left and the other right. It was more a scrotum problem than a penis problem. The penis would obviously go whichever side the scrotum went. Some men preferred the left side, some the right. Tailors would never be so rude as to assume which side the gentleman preferred his dangly bits to hang, but would always ask which side they "dressed". For a tailor's regular customers, this information would be noted the first time, and would be used when making future trousers. I have certainly had this question asked of me. It happens far less these days, mainly because trousers generally have a different shape and the problem is avoided, but also because a lot of guys would consider this a ludicrous invasion of privacy, and no shop wants its staff exposed to charges of inappropriate questions (or even sexual harassment). How times have changed. JackofOz06:58, 3 May 2006 (UTC)[reply]
Strangely, a friend of mine was talkin about this "dress left/dress right" thing the other day, and wondering if it was the exact reverse of handedness (right-handed=dress left and v.v.) Neither of us was keen to conduct a survey, though. Grutness...wha?07:40, 4 May 2006 (UTC) (r.h./d.l.)[reply]
Oh Grutness, you're unbelievably shy when it comes to legitimate scientific research. Live dangerously occasionally. :--) JackofOz23:50, 5 May 2006 (UTC)[reply]
What's the easiest way to identify the exact species of various trees I spot in Toronto? Do I need to buy a field guide, and if so which one is best suited for my needs? Do I need to take pictures of the leaves or analyze the bark, or is there some sort of DNA test I need to do to figure out the exact species?--Sonjaaa02:56, 3 May 2006 (UTC)[reply]
A little book, or a field guide is good. I can't think of the one I used when I was in Michigan though... Auto something... or something. He was a bird guy. -- Mac Davis] ⌇☢ ญƛ.04:27, 3 May 2006 (UTC)[reply]
If you are talking experimental results, maybe you are underestimating force and overestimating charge somewhere. (E.g. your charge is leaking away somehow) --137.205.17.15911:55, 3 May 2006 (UTC)[reply]
Solubility of Ethanol
I've learned in my Chem class that polar substances dissolve in polar solvents,eg NaOH dissolves in water.Non-polar substances do not dissove in polar solvents and vice-versa.Why does Ethanol(C2H5OH) dissolve in water?
This is not a homework question.Just wondering.
Thnx
Isn't it because ethanol is polar? Water should dissolve polar substances, in general. The hydroxyl group should make ethanol polar enough to dissolve in water. — Knowledge Seekerদ08:13, 3 May 2006 (UTC)[reply]
That dangling hydroxyl group has an acidic proton on it. Pretty much any time you see oxygen covalently bound to something, it's going to be a polar bond. Isopropyl12:45, 3 May 2006 (UTC)[reply]
Right, some molecules have polar and non-polar portions of the molecule, Ethanol is one of these. Often it means these will dissolve in either kind of solvent.
Yes in general polar substances dissolve polar and non-polar with non-polar, but the reason why it happens at all is intermolecular forces. There are a few types of these forces, but the ones that are important for these examples are London dispersion forces, dipole-induced dipole forces, and hydrogen bonds. Think of as two parts, the hydrocarbon part () and the hydroxyl group (). Between water and the hydrocarbon part there are are dipole-induced dipole forces and between water and the hydroxyl group there are hydrogen bonds. The water molecules are bonded together by the same hydrogen bonds while the ethanol molecules are bonded by hydrogen bonds(hydroxyl part) and London forces(hydrocarbon part). Since hygrogen bonds are strong and the hydrogen bonds between the water molecules and the polar (hydroxyl) part of the ethanol molecule have about the same strength the molecules attract each other about the same amount as the forces between two water molecules or two ethanol molecules. As such, they can easily be substituted for each other in bonds (and because of the shape of the molecules there are not many bonds being distrubed by this switch).
As it turns out ethanol is also miscible in hexane (). The hexane molecules are bonded together by London forces. Between hexane and ethanol the main forces are London forces between the hydrocarbon parts and dipole-induced dipole forces between the hydrooxyl group and hexane. Together these are about the same strength (in this case) as the H bonds between the ethanol molecules so the bonds are easily interchangable.
London forces generally increase with molar mass and more surface area. As the hydrocarbon chain grows to say hexanol () the London forces play a greater role. Now the forces between the hexanol molecules, largely dominated by London forces over the H bond interactions, is stronger than the H bond between water and the hydroxyl group of hexanol. There is also the issue that the hydrocarbon part of hexanol gets in the way of more H bonds between water molecules. As such, hexanol is not very soluble in water but still miscible in hexane.
If you go the other way and reduce the hydrocarbon chain to methanol () the opposite occurs. The methanol molecules have the same interactions with themselves, but the London forces are weaker. Thus, the London forces between it and hexane are also weaker and the H bonds between methanol and itself and the London forces between hexane and itself dominate and methanol is not very soluble in hexane. However, it is miscible in water. This is because the London forces between methanol molecules is tiny and the H bonds between methanol and methanol, water and water, and methanol and water are interchangable.
Basically, the greater the forces between two different molecules are in relation to the molecule's forces to itself determine how soluble something is. Generally, two polar substances or two non-polar substances will have greater intermolecular forces between each other than a polar and a non-polar so that is why most solvent-solute pairs are of the same polarity. Kotepho14:30, 3 May 2006 (UTC)[reply]
The short answer is that where solubility is concerned, polarity doesn't have a strict binary yes/no effect. Polarity is a sort of continuum, running from ionic compounds that will dissociate into charged monatomic ions in solution (NaCl forms hydrated Na+ and Cl- in water, for instance) to covalently-bound molecules with a significant dipole moment (methanol or formaldehyde, say) to predominantly nonpolar molecules with some polar groups (long chain alcohols like n-octanol) to completely nonpolar species like carbon tetrachloride or cyclohexane. Solubility will depend on the difference in polarity — as well as a huge pile of other factors that influence the interactions between molecules. TenOfAllTrades(talk) 15:22, 3 May 2006 (UTC)[reply]
Fly-by-wire
Since solar flares are a threat to satellites are they not also a threat to fly-by-wire technology?
Incidentally, I just found a very interesting set of FAQs about aircraft safety here but the guy who runs it has just retired. --Shantavira08:08, 3 May 2006 (UTC)[reply]
Yes. In principle, solar flares are a threat to any and all electronic technology, and plenty of non-fly-by-wire aircraft are more-or-less equally vulnerable to flares (say, when computers regulate the flow of fuel). However, in practice, aircraft fly under the primary protective layers of the atmosphere, so they're far less vulnerable to flares than satellites. — LomnTalk13:08, 3 May 2006 (UTC)[reply]
Also, most commercial aircraft have triple-redundant primary systems, so even if one computer is knocked out, there are two backups. — QuantumEleven13:30, 3 May 2006 (UTC)[reply]
This is not as comforting as it seems, since, if one computer is knocked out by solar radiation, all three are likely to be. A problem also arose where an escape door blowing off knocked out the hydraulic tail controls, all three redundant systems went through the same place! 165.254.38.12604:57, 4 May 2006 (UTC)[reply]
How do you improve the google rank of a Wikipedia article, e.g. Opus Dei
Hello fellow Wikipedians! I've been helping edit the article at Wikipedia. I've seen it rise in google rank over time. It is now ranked four, but as you know many Wikipedia articles rank number one. Thus, I also want to know if there are other techniques specific for Wikipedia to improve ranking. FYI, I've done my own search in Wikipedia and read Search engine optimization and other related articles.
Another issue. The pagerank of Wikipedia's Opus Dei article is 6/10 when I use the pagerank at the google toolbar. However, I found out that the Unofficial Homepage which has a google search rank of number two has a page rank of 5/10. This means it has a lower pagerank than Wikipedia's Opus Dei but it is still higher in the google search. Why could it be so?
I think google rank is determined by the amount of people that link to it and the amount of places the article links to. Since spamming the article is out of the question, it might be helpful to ask people with relevant sites to link to Wikipedia. Where a page turns up in the search results not only depends on google rank but also on the meta tags of the site in question and the content of the page itself and the number of visitors. Wikipedia's results placement will improve on its own. - Mgm|(talk)09:34, 3 May 2006 (UTC)[reply]
You have things a little backwards, I think. PageRank is determined by what pages link to the article, not the other way around. If the article links to too many pages with low PageRank, though, its own PageRank can be decreased as well (it is a way to penalize link farms). The easiest way to raise the article's PageRank is to link to it from a page which already has a high PageRank. (Easier said than done, but it can be done.) --Fastfission20:50, 3 May 2006 (UTC)[reply]
May I ask why Google rank is important to you? Wikipedia is about writing the best possible articles on a subject - the better it is, the more people will link to it, and Google rank will come all by itself. But it's a secondary benefit and not the main reason for writing a good article - I would frown on blatant search engine optimisation at Wikipedia. — QuantumEleven13:24, 3 May 2006 (UTC)[reply]
Maraming salamat sa inyong lahat! (that's "thanks to all" in tagalog). Thanks, Fastfission, and congratulations on the article. I suppose when you said it can be done, it means requesting webmasters to put a link on Wikipedia?
Regarding Quantum's question, I completely agree with her/him that it's all about good writing, but I am also interested in countering the black propaganda done by the maker of the Unofficial Homepage who is a communist. I have nothing against him personally, but his ideas are propaganda and propaganda = misleading information. Wikipedia has more balance and more expert, trustworthy information. It would be great if more people get to read it. Thanks for all the help and whatever other help you can give. Salamat! Cabanes01:53, 4 May 2006 (UTC)[reply]
On some level this is out of your hands. At least the official Opus Dei site is number one. But ultimately you're just going to have to trust people's critical thinking and source evaluation skills.
Have you ever wondered who makes all these conspiracy theories up, and whether they have some secret reason for doing so? I think that this should be investigated... Grutness...wha?07:45, 4 May 2006 (UTC)[reply]
Of course it would be Gagarin. Sorry I wasted your time by asking such a silly question. Anyway thanks for the answer.
--Siddhant11:24, 3 May 2006 (UTC)[reply]
... although it is interesting to note that first non-stop aerial circumnavigation of the the Earth was completed as early as 1949 by the crew of the B-50 SuperfortressLucky Lady II. Gandalf6112:04, 3 May 2006 (UTC)[reply]
Jean Michel Jarre has a song "Hey Gagarin" (Métamorphoses album) about Gararin orbiting Earth, with these cool lyrics: "I can fly, I fly like a sputnik, listen to the music spin, around the planet and lets, dance together".--JLdesAlpins22:36, 3 May 2006 (UTC)[reply]
In any case, in case you're interested, the first true BITCH to orbit the earth would have to be the Russian Laika. But since she's a bona fide BITCH, you may not be interested. I, myself don't consider BITCHES like Laika to be human beings. But that's just me. You may want to call me a misogynist for saying that, but I think you'd be wrong. I may be letting my personal feelings to get in the way of an unbiased analysis, or maybe not. Loomis5101:46, 5 May 2006 (UTC)[reply]
PVC protection
How can we protect workers who make PVC from the harmful effects of Vinyl chloride?
I'd imagein all the usual methods (fume extraction, respirators, good equipment design, automation etc) can be used to reduce exposure to safe levels. Plugwash00:48, 4 May 2006 (UTC)[reply]
Book about synthesizers
I've downloaded Chaosynth and its manual provides too little information about the physics of the sound and so. Can anyone recommend me an information source that speaks extensively about the subject? Thank you.
How about a website about synthesizers? Sound On Sound magazine ran a very detailed series called Synth Secrets, and it's all up on their website at www.soundonsound.com , however I couldn't seem to find a good index to the series on their site, but there's a great one here: http://www.adp-gmbh.ch/csound/synth_secret.html --Noodhoog15:55, 4 May 2006 (UTC)[reply]
Multiple choice!
Which of the following statements is true?
A. Electrons are negatively charged and are found in the nucleus of an atom.
B. Electrons are negatively charged and are found outside the nucleus.
C. Neutrons are positively charged and are found in the nucleus.
D. Protons are positively charged and are found outside the nucleus.
Please see the top of the page regarding not asking us your homework questions. Your textbook doubtless includes the answers but in case you haven't got it handy our articles on electron, neutron, proton, atomic nucleus and atom should tell you everything you need to know, and much more besides. --Bth12:58, 3 May 2006 (UTC)[reply]
Some do, some don't. Electrons were thought to all revolve around the nucleus in older models of the atom. See atomic orbital and magnetic quantum number for a current view. (The latter because the magnetic quantum number is related to the electron's angular momentum, and whether it has non-zero angular momentum or not might be one reasonable intepretation of whether an electron "revolves" around the nucleus.)Chuck17:35, 3 May 2006 (UTC)[reply]
2. Protons are positively charged.
3. Positive and negative charges repel each other.
"Positive and negative charges repel each other" - this is a little awkwardly phrased; 'like' charges repel so two positively charged particles (or two negatively charged ones) will repel each other, but a positive particle will be attracted to a negative one. Yummifruitbat16:06, 3 May 2006 (UTC)[reply]
Yes, very true. An exam question that I got a few days ago: "A covalent bond is a shared pair of electrons. Explain how this holds the atoms together." The answer is, of course: The positice nuclei are attracted to the negative electrons; which, overall, results in a neutral atom. This was actually in a prelim and this was a question that was in an actual Credit exam in 2001. Kilo-Lima|(talk)18:57, 3 May 2006 (UTC)[reply]
I'm not sure what you mean by the above - a covalent bond results in a molecule with the two atoms sharing electrons in order to achieve full outer electron shells. This is not really relevant to the original question and I fear you may have misunderstood the exam question :( Yummifruitbat22:21, 3 May 2006 (UTC)[reply]
I am extremely sorry. Positive and negative charges attract each other. Like charges repel each other. I am really sorry. The correct answer would be B. You are right Chuck. That was a small mistake I didn't notice it. Electrons in an atom always revolve around the nucleus. I think this question is about a simple atom not a covalent compound. Elctrons can be found freely but this is not about charge or radioactivity. It is a simple question on the structure of an atom. Negative charges can also be found inside the nucleus (β particles). But that is not important over here.--DIGIwarez07:24, 4 May 2006 (UTC)[reply]
A negatively-charged beta particle is an electron. And D can also be true -- protons can be found outside the nucleus in many high-energy situations (though I suppose it can always be argued that they're hydrogen ions, though in such cases that's not a helpful way to look at them). The only one that's 100% always false is C, becauses neutrons simply aren't positively charged. --Bth07:43, 4 May 2006 (UTC)[reply]
True, but the person who asked this question was probably not looking for all this. I think this is about the basic structure of an atom. We are making this too complicated.--DIGIwarez07:53, 4 May 2006 (UTC)[reply]
Oh yeah, this is obviously a middle school level question with an obvious correct answer (not obvious enough that the questioner could get it, mind). However, you can't ask such a question to a bunch of people with more advanced knowledge without expecting them to caveat the hell out of it -- it's human nature. --Bth09:33, 4 May 2006 (UTC)[reply]
Can a proton be outside a nucleus, I don't think so as a proton defines a nuclei. A proton on its own with no electrons or neutrons, is not just a proton it is a hydrogen nuclei. So only A and B are possible. PhilcT+C21:43, 4 May 2006 (UTC)[reply]
RoHS Directive
In the Restriction of Hazardous Substances Directive page (2002/95/EC), paragraph 4 under "Details" states the maximum concentration of Hexavalent Chromium by weight of a homogeneous material is 0.1%. Where is that stated in the Directive? Thank you.
Is that an English Comprehension homework question? And isn't the answer to the question contained within the first sentence? --Shantavira16:13, 3 May 2006 (UTC)[reply]
Generally body mass correlates with brain size (see brain to body mass ratio). Brain size does not correlate to "species" necessarily, especially with there is high variability in body size within a species (such as with dogs). --Fastfission01:10, 4 May 2006 (UTC)[reply]
gas mantles (non radio active gas mantles)
does any body know what are the latest coleman non radio active gas mantles made of and what would be the appropriate composition and formula for making a durable ,strong ,bright white light gas mantle(non radi active ) and has there been further develoment in this particular area and by whom.
Wow, this attached encyclopia-thing always fails to amaze me! I typed in 'gas mantle' and I found out that your little Coleman is radioactive! but probably as much as smoking one ciggie. The problem is with mantle factories handling truckloads of thorium. Apparently, the substitutes don't work as well. --Zeizmic20:18, 3 May 2006 (UTC)[reply]
Indeed; I'd be more worried about the health effects of the combustion byproducts generated while the lamp is still warming up—sooty things like polycyclic aromatic hydrocarbons, which are known carcinogens. (If you've been exposed to smoke from you campfire or barbecue, too, then you might as well give up now.) The exposure to radiation from the lamp mantle is negligible unless you're eating the darned things. TenOfAllTrades(talk) 20:37, 3 May 2006 (UTC)[reply]
Where the 'proder' doesn't bother to research the article.
Computer science
WP offers a search bar with two buttons, Go and Search.
Firefox offers search engines but the WP one only ... searches. Does anyone know about a "Go" engine ? Thanks a lot. --DLL20:06, 3 May 2006 (UTC)[reply]
Thanks! I never used the stupid search bar because it always went to a search result list. It was quicker to bookmark Wikipedia and use the page's search box. --Kainaw(talk)23:14, 3 May 2006 (UTC)[reply]
This is NOT the place for medical consulting, I know that, but this is of no importance, and not exactly a thing I'm gonna see a doc about. I just noticed that on my right eye, there was a bit of pink discolouration. So I look closer in the mirror, and it looks like some veins that have blown or something. Nothing big, just a tiny bit of pink (no intense red) that's not noticable for anyone not looking closely, focusing on it. What could this be? More importantly, what could it be caused by? Although it's hard to describe it, I can clearly see that there are some veins there, so it's not some sort of spot that's flooded with blood. Thanks in advance! 213.161.189.10722:24, 3 May 2006 (UTC) Henning.[reply]
There are blood vessels in the eye, and they can burst. Pressure, shock, randomness etc can cause this, and in moderate amounts it's normal and will disapear pretty quickly. See someone if it persists for more than a few days. 165.254.38.12622:46, 3 May 2006 (UTC)[reply]
I like to feed the gulls (herring gulls, lesser and greater black-backs around here). I get together a big pile of scraps and leave it out in the garden for them and watch them feeding through the window.
Invariably, as soon as one of the flock of gulls I've attracted descends and picks up a piece of food, the rest of them immediately get angry and give chase to that single bird across the sky in an attempt to rob it of its meal - completely ignoring the fact that there is about 2lbs of meat/cheese/bread/etc. just sitting there on the ground.
Why are gulls seemingly more intent on expending time and energy to deprive another gull of food when by simply cooperating and putting aside their squabbles for five minutes, they would all be able to gather round and eat plentifully from the pile? This doesn't make sense to me at all (actually, it seems like a very human mindset). :)
Quite often, while the rest of the gulls are flapping, bickering and screeching in the sky above, a single bird will land at the food and quietly and calmly eat its fill then leave before the others have given up the fighting and noticed. Thus, the 'jealous' majority miss out. Do you think that this is a sign that this particular gull is more intelligent than the rest?
As someone else, somewhere online once put it - a gull's mindset seems to be "Everything that's mine is mine. Everything that isn't mine is also mine". :)
1) Perhaps having "excess food" is so out of their normal experience that they don't know a different behaviour would be beneficial in such cases. That is, they are going strictly by instinct, which developed based on food being scarce.
2) The fighting over food may also be a way of establishing dominance, which may also come into play during mating.
3) They might want to avoid landing for fear of predators, like dogs.
Just wanted to remind ya'll that feeding the birds is generally discouraged if you wish to keep droppings off your aerially exposed surfaces. Isopropyl04:02, 4 May 2006 (UTC)[reply]
Nah, just catch 'em, cork 'em, then let 'em go. :-) 17:57, 4 May 2006 (UTC)
Foreskin redux
This was asked further up the page a few days ago but no-one replied. Is a 'normal' foreskin supposed to retract fully behind the head of the penis when it's erect? Thanks. --84.71.80.23900:44, 4 May 2006 (UTC)[reply]
When mine is pulled back the most it can go comfortably, mine doesn't go behind the head. It only reveals a little bit of it, but even then, just barely. But really, your question is too ambiguous. What does "normal" and "head" mean? Not that I'm an expert, but everyone's body is different. If I were you, I'd try not be overly concerned about what is "normal", and focus more on what's comfortable for you. --69.156.159.5901:06, 4 May 2006 (UTC)[reply]
"Head" is pretty standard, and means the lumpy bit on the end that generally doesn't become really prominent (if I remember right) until somewhere during puberty. I hope it doesn't need to be pulled back much, since mine hardly does at all. No matter what state it's in, it always covers the entire head, with of course an opening of varying size, and pulling it back farther than that feels rather like pushing back my cuticle or giving blood: not pleasant, in a weirdly uncomfortable way. I can't imagine this ever causing me problems, and in fact I was amazed to find out it can work any other way short of circumcision. A word of advice, based on the conversation above: don't mess with it until it's actually a problem, and consider finding a second opinion. Doctors have been known, like everyone else, to talk out of their asses at times. Black Carrot01:16, 4 May 2006 (UTC)[reply]
In the foreskin article, doesn't it say that "[a study] found that about 50% of young men had full coverage of the glans, [and] 42% had partial coverage"? Black Carrot01:25, 4 May 2006 (UTC)[reply]
Have you read phimosis? I think it's only likely to be considered a problem if it can't be retracted fully even when flaccid,and even then opinions are divided about whether there are any serious implications. Yummifruitbat01:30, 4 May 2006 (UTC)[reply]
Digg is essentially just a collection of links to other sites, plus comments. The sites linked tend to be reasonably mainstream, though, rather than some sort of crackpot link collection. I would take essentially anonymous one-line comments on a website with a grain of salt. (Oh the irony!) As far as scitech goes, I'd put the collective intelligence of Slashdot ahead of Digg. The two stories you've linked seem like the classic "idea papers". Someone comes up with a novel idea, and the physics that might theoretically work; they write a paper because it's more fun than real research, the university promotes it because it's easier to get public attention than real research, and BBC prints it because it's cooler and more interesting than real research. So yes, they're theoretically correct. But moving from theory to practice may well be impossible. How long have there been blueprints for a space elevator, for instance? --ByeByeBaby01:48, 4 May 2006 (UTC)[reply]
This is not an attempt at vandalism, so pls don't revert my question. :)
My (male) macaw likes to rub his butt area against his toys and perches and seems to get really excited when he does this. He goes faster and faster, hooking his tail under whatever he's humping before he stops and sits there panting with his feathers fluffed up. It looks to me like he's getting himself off and cumming. Is he? Do birds really masturbate? Should I try to stop him doing it?
I doubt you could stop him. Males of most species are remarkably persistent this way. :D
Sounds like the poor guy could do with some female company. If you don't want to buy a lady macaw perhaps a date could be arranged.--Shantavira08:45, 4 May 2006 (UTC)[reply]
Raising parrot chicks is a major commitment and very time-consuming. Attempting to breed the bird without lots of knowledge and preparation is probably not a good idea. In other words, he should practice planned parrothood. --Ginkgo10019:53, 5 May 2006 (UTC)[reply]
He probably is masturbating. Birds have no concept of 'sinful' or 'inappropriate' behaviour. It's a natural bodily function - I'd just let him get on with it. If you try and stop him (some bird owners squirt their pet in the face with cold water from a plant mister when they catch them wanking), he'll just get cranky and aggressive from the hormone buildup. --Kurt Shaped Box17:54, 4 May 2006 (UTC)[reply]
Just to be sure here, it's not just male birds that are apt to that sort of behaviour. I once had a female parakeet who, on several occasions, would rather disturbingly raise her tail and develop a rather scary look on her face whenever I'd take her out of her cage. Needless to say it wasn't long before she laid an (unfertilized) egg. This happened several times. I actually tried to get her a male companion but she was so territorial that after a couple of weeks I found the male dead at the bottom of the cage. A clear case of ornicide. Oh well, at least I tried. Loomis5101:31, 5 May 2006 (UTC)[reply]
Kiwi Birds
My daughter needs a source to interview for a report on kiwi birds. Any ideas of where to obtain a speciallized individual on kiwi birds?
Dg202:54, 4 May 2006 (UTC) Thanks dg2[reply]
In fact, the June solstice is the first day of summer. Consequently, the North Pole is tilted towards the sun (to varying degree) for the entirety of both Spring and Summer (and for none of Winter and Autumn), and the tilt is split evenly between the two. — LomnTalk13:26, 4 May 2006 (UTC)[reply]
Of course that's only in the northern hemisphere. Don't forget the Aussies! (And others like South Americans) For them, June 21/22 is the winter solstice. (You can thank me later, Jack!) Loomis5102:21, 7 May 2006 (UTC)[reply]
Nitrogen's atomic spectrum looks kind of golden yellow. [11] hyperphysics with pretty pictures of elements in spectral tubes. NOTE: spectral tubes are not flames, however both methods look at excited electrons. Nitrogen can't burn but we can shoot electrons at it and get the same results. Sifakatalk04:58, 4 May 2006 (UTC)[reply]
Doesn't nitrogen "burn" during a lightning strike? (Though the colour of lightning isn't the colour of burning nitrogen.) --Bth09:06, 4 May 2006 (UTC)[reply]
Reaction energy depends on entropy, which depends on temperature. A reaction which is endothermic at one temperature can be exothermic at another. For instance O2 + 1/2 N2 --> NO2 is endothermic at room temperature but exothermic at temperatures above ~190 C. --BluePlatypus15:40, 4 May 2006 (UTC)[reply]
Mac Davis: Nitrogen does indeed burn at sufficient temperature, forming nitrogen oxides. NOx production is an environmental problem with any sufficently hot combustion using air as an oxidant. It's why we've got catalytic converters on cars. --BluePlatypus15:31, 4 May 2006 (UTC)[reply]
Why does burning hair smell bad?
Hair has a lot of disulfide bonds (cystine I assume), and I assume it is liberated in the form of malodorous molecules, but is there a primary molecule or class of molecule (more specific than sulfides) that causes the stench? Sifakatalk05:12, 4 May 2006 (UTC)[reply]
In my (extremely limited) experience, shoeing horses and cauterising wounds produces the same unpleasant smell. That suggests there's nothing specific to hair.Notinasnaid09:22, 4 May 2006 (UTC)[reply]
That's because the same class of proteins - the keratins make up hair and epidermis. Someone else wrote already that they are rich in cysteine, a sulfur-containing aminoacid. Sulfur compounds smell bad, as a rule. Dr Zak11:50, 4 May 2006 (UTC)[reply]
Why do we consider burning certain proteins a bad sensation ? 1) If it is our kin, there is a conservation thought, 2) if it is food (or foe), that indicates too much cooking. --DLL21:03, 4 May 2006 (UTC)[reply]
All creatures find the smell burning creatures (particularly their own) disturbing, much in the same way that we don't like dead bodies, it has benefitted the human race through evolution to be scared of death, and generally burning human is closely associated with death. PhilcT+C21:31, 4 May 2006 (UTC)[reply]
Also, in general, gaseous sulfur compounds are poisonous in high concentrations, so it make sense that low concentrations stink: it encourages you to leave before you get killed. --Serie21:34, 4 May 2006 (UTC)[reply]
Zero Gravity
Is it possible to achieve zero gravity on earth?
If by "zero gravity" you mean weightlessness, then yes: just go into freefall. Ways of acheiving this include being in an out-of-control lift (not recommended because of the crash landing at the other end), the early part of a parachute jump or flying a plane in a parabolic arc (see Vomit Comet, a name applied to any of several planes used for astronaut training -- one was also used for the weightless scenes in Apollo 13). Deep-sea diving provides a similar experience to weightlessness, because of the support provided by the water, and indeed much astronaut training takes place in huge tanks. --Bth07:28, 4 May 2006 (UTC)[reply]
When you jump into the air and then fall back down, for about one second you're in zero-gravity. Try holding something like a ball in a cup (or a glass of water, if you don't mind getting wet) while you fall down. The ball will float inside the cup and it's really cool! JonathantalkFile:Canada flag 300.png17:20, 4 May 2006 (UTC)[reply]
If you were in zero gravity, you would not fall back down when you jumped, so your are in gravity, and if you are on earth that is 1G of gravity, you are however weightless, i.e. if you jump out of a plane and stand on some scales as you fall, you will register zero (discounting effects of air resistance). PhilcT+C15:40, 7 May 2006 (UTC)[reply]
Zero gravity can only be acheived outside the universe, or debatably at the centre of mass of the universe. PhilcT+C21:32, 4 May 2006 (UTC)[reply]
Continuing from Jonathan, even when you jump off from a small height (say from the top of a table or a small ladder (basically when you are experiencing a free fall), you are in zero gravity -- Wikicheng23:57, 4 May 2006 (UTC)[reply]
Trampolines (especially the really big ones at the local gym) are brilliant for this kind of experiment - from the moment you take off to the moment you land, you are (barring a small component of air resistance) weightless. Although you may want to ask before doing Jonathan W's experiments... :) — QuantumEleven06:55, 5 May 2006 (UTC)[reply]
Airplane Safety
Can diesel be used in a high compression ratio jet engine so as to enhance safety in case of a crash as diesel does not catch fire due to sparks and spillage?
Diesel engines for airplanes exist, do check our article on aircraft engines and most especially aircraft diesel engines. In short, diesels do very well at running at medium power for extended times (operating consditions in aircraft); what prevents wide adoption is the small market combined with the extended certification process. Dr Zak11:56, 4 May 2006 (UTC)[reply]
I believe a variant of Kerosene is used as jet fuel, because it does not burn as vigorously as gasoline.
Physics Question
According to the formula e=mc², it is possible to get a lot of energy from a very small amount of mass. Practically, we lose of a lot of energy in every machine. If we burn a lot of coal, a huge amount of it is wasted as ashes. Even in nuclear power plants, a lot of radioactive material is wasted as nuclear waste. Is there any(practical/theoretical)way to convert the whole of a substance into energy without wasting much?
Matter-antimatter reactions are pretty much the only candidate for total conversion of rest mass, though even that ends up with a substantial amount of the energy going into neutrinos. Very much a theoretical option, and even an arbitrarily advanced society would have trouble making antimatter without expending a vast amount of energy.
There is the possibility of collecting small amounts of antimatter (but enormous compared to what we can currently produce) in the magnetic fields of various bodies in the solar system. See [this Nasa Institute of Advanced Concepts study. However, the cost and complexity of such collection mean it's unlikely to be used as a domestic power supply; it'll almost certainly be used only where energy density is really important like spacecraft propulsion. --Robert Merkel02:03, 5 May 2006 (UTC)[reply]
In nuclear power plants, there is probably not as much waste as you think. Its a lot heavier, but by volume it is pretty small. (Comparison of medium sized nuclear power plant's fuel consumption to a man, ~6 ft. tall. Matter-antimatter reactions annihilate totally, releasing heat and light, with no waste matter (there is still waste, but only in energy form). It still takes a lot to generate that antimatter though. Nuclear fusion is probably the best way to go in the next few hundred years, supplemented by solar panels, if they are cheap and efficient enough. -- Mac Davis] ⌇☢ ญƛ.09:05, 4 May 2006 (UTC)[reply]
I think the questioner is seeing all matter left over as possibly-energy-by-E=mc2 and thus views both ashes and nuclear waste as huge amounts of rest mass just sitting there going to waste.
In general, combustion releases energy from chemical bonds, which is absolutely tiny compared to rest mass (less than a millionth of one per cent), and both nuclear fission and fusion release nuclear binding energy, which is on the order of 0.1%. --Bth09:19, 4 May 2006 (UTC)[reply]
I know about the small amount of enrgy which is released through combustion and also the nuclear binding energy which is released in fission and fusion reactions. I just wanted to know whether the total annihilation of matter and the subsequent release of energy is possible or not. The examples that I used in my question were probably not correct.
Thank you very much, but what about cold fusion? Is it really possible to make small scale fusion batteries?
How can polymerization be used to make PVC soft without using plasticers? Thanks in advance.
While this is just an educated guess (my schooling in polymers was limited) I'd say that using 2 different monomers with different spacial properties to polymerize randomly, you would end up with strains with random spacial properties, that are unable to neatly fit next to each other. And i do believe that the degree of order in a polymer is a strongly related to it's hardness. I've always seen it as the difference between the different in a bundle of Pick-up sticks lying neatly together, or it being a jumble. And this forces a jumble by bending sticks in different random places. SanderJK10:37, 4 May 2006 (UTC)[reply]
Well, it depends on where you're starting from. If you've already got the PVC, there's not much that can be done by polymerisation (other than melting and mixing with another, softer, polymer) to make it softer. However, if you provide enough heat to raise the sample above its glass transition temperature, it'll become soft and flexible. If you're starting with the monomers, you can control the degree of polymerisation by a number of means, and this'll affect the physical properties of the polymer produced, including rigidity. Generally, the lower the molecular weight distribution, the softer the polymer. Unfortunately, Polyvinyl chloride is produced via an addition reaction rather than a condensation reaction, so I can't point you to the Carother's equation, but by adding another chemical capable of reacting with the vinyl chloride into the mixture, the average chain length should be decreased, and the polymer made softer. GeeJo(t)⁄(c) • 21:17, 4 May 2006 (UTC)[reply]
Anything you add to the PVC could be construed as a plasticezer because you are taking away from the purity of the end product. The best way to do this is to create a plastic that is more amorphous (non-crystaline) which will make the plastic more of a tangled mess of molecules thrown together in a ball rather than an ordered crystal which is much more rigid. The best way to do this is to heat the plastic past its melting point until it is in a near liquid form with a lowered viscocity. Mix it well then super cool it. This will shorten the chains as you have broken some of the intermolecular forces of the original plastic and it will take away from the crystalinity. However once you do this it will severely degrade the plastic.
True. Also, since the reaction forming PVC is based on a fre-radical chain, it's highly susceptible to temperature. So to add to my previous statement, provided you're starting with the vinyl chloride monomers, altering the reaction temperature (and keeping it regulated since the reaction is exothermic) is also a viable method of changing physical properties of the polymer. GeeJo(t)⁄(c) • 23:51, 5 May 2006 (UTC)[reply]
Converting pdf file to editable format
Hello, Is it possible to convert a pdf file (Adobe Reader 6.0) to a text format that I can edit. As it is currently Acrobat won't let me select anything to copy & paste it, when I try to save as text it saves a blank txt file & when I try to copy the file to the clipboard & paste it it doesn't paste anything. AllanHainey09:47, 4 May 2006 (UTC)[reply]
If a PDF file is not protected and contains text, Adobe Reader will let you copy/paste the text into other applications. From this we can conclude that the PDF file you have does not contain text. It's most likely scanned pages, big pictures with no text at all. The only solution would be OCR (available in commercial Acrobat and other tools). Notinasnaid09:53, 4 May 2006 (UTC)[reply]
A pdf file can be protected so that you are not allowed to select from it even though it is not password protected. So it is still text format and not a picture, but acrobate reader refuses to let you select from it. It is possible to convert a file like this to text using a pdf to text converter IF it ignores the select lock flag. Open source and freeware software is most likely to do so. Good luck. Stefan10:15, 4 May 2006 (UTC)[reply]
This is indeed a possibility, but in such a case Reader would also refuse to save text. Since it allows you to save text, but saves nothing, I have to conclude there is no text. Notinasnaid11:05, 4 May 2006 (UTC)[reply]
You can use a software called PDF to Word v1.6 to convert PDF files into RTF format. RTF files can be edited normally with a text editing software(MS word for example). This software is not free. You can get it at http://www.verypdf.com/pdf2word/index.html. This is not an advertisement, you can use any other software if you like.--DIGIwarez10:06, 4 May 2006 (UTC)[reply]
But does this software do OCR? I can't see any mention of this on its web page. Without OCR, it's likely to produce a word file with a picture of a scanned page. Just like the picture in Reader, not editable text. Notinasnaid10:06, 4 May 2006 (UTC)[reply]
No this is not an OCR. It works on a normal non-scanned PDF file. Please try it if you have any doubts. It's free for a limited amount of files. You should be able to edit the text portion quite easily.--DIGIwarez10:27, 4 May 2006 (UTC)[reply]
So I think we have to assume that it won't help the original questioner? Since if it was a normal non-scanned PDF, they would have been able to copy/paste or save text? Notinasnaid10:33, 4 May 2006 (UTC)[reply]
The questioner asked for a software with which he could convert a PDF file into a text file. The above software can do that. If it fails then an OCR software might be necessary.--DIGIwarez10:41, 4 May 2006 (UTC)[reply]
Thanks, it looks like the pdf document is just scaned pages so I'll look into OCR, anyone know a good free OCR software? AllanHainey12:12, 4 May 2006 (UTC)[reply]
OCR is often pretty bad with PDFs. You'll probably do better to just print it out and then re-type it -- because you will probably have to go over and check every single word for OCR errors anyway. OCR is useful for searching documents, but it is not very good for replicating their exact text, in my experience with Adobe Acrobat's OCR functionality. --Fastfission16:11, 4 May 2006 (UTC)[reply]
Radioactivity
If β-particles are negatively charged, how can they stay inside the nucleus?
They don't. They're emitted at high speed. But they start in the nucleus, hence all the hairsplitting in the previous question. (And note that being negatively charged shouldn't prevent them staying in the nucleus at all, as negative and positive charges attract one another; it's the high energy from their being created in a nucleon's decay that means they shoot off. What should surprise you is that the protons in the nucleus don't all repel each other, which is down to the strong nuclear force.) --Bth10:07, 4 May 2006 (UTC)[reply]
By negatively charged particle I meant electron. I could not understand how electrons were produced inside a nucleus. Thanks for the answer
I think what you are trying to ask is how protons can stay in the nucleus together despite their mutual electrical repulsion due to their positive charges. The answer is that the nuclear force is a stronger attraction than their electrical repulsion, at that distance. StuRat18:17, 4 May 2006 (UTC)[reply]
dieting
i recently heard that dieting DOES NOT reduce the amount of body fat.Then why do people recommend & follow it?
I suspect someone has played a prank on you (or is trying to sell you a snake oil dieting product of some sort). See dieting, in particular the section How the body gets rid of fat. 12:33, 4 May 2006 (UTC)
I have seen someone lose weight with this kind of diet (Actually, it was Big Macs and beer). After three months of it, he had lost something like 20 pounds. If you can successfully force yourself to only eat one, it probably wouldn't be long before you get sick of it. - user:rasd
why does sugar mix well in hot milk than cold milk?
thanks!
Milk is mostly water. If you've ever tried to make lemonade or Kool-Aid before, you know that it is easier to mix the sugar in water if you use hot water and then refridgerate it. Of course, that takes a long time, so you have to suffer through that first warm glass with some ice cubes. --Kainaw(talk)13:35, 4 May 2006 (UTC)[reply]
It takes energy to break apart the sugar molecules making up the crystals. By heating the milk, you increase the average temperature of the sugar/milk mixture farther above the activation energy of the solvation reaction, and so make it easier for the sugar to dissolve. GeeJo(t)⁄(c) • 20:57, 4 May 2006 (UTC)[reply]
Simple Answer: Milk is made of molecules that whizz around, bumping into each other. Sugar is also made up of molecules, but they are 'holding on' to each other, making them solid instead of liquid like the milk. When a milk molecule hits a sugar molecule, if it's going fast enough and strongly enough it will break the sugar molecule off the lump of sugar and dissolve it in the milk. The warmer the milk is, the faster the milk molecules whizz, and the harder they hit the sugar molecules. Also, as they are moving faster, they hit the sugar molecules more often. This means they break sugar molecules off more often, dissolving the little lumps of sugar faster. Skittle16:01, 5 May 2006 (UTC)[reply]
Disposal of nuclear waste/material
Hi again, a U.K. committee set up by the government to look into the best ways to dispose of nuclear waste/materials recently reported the best way would be to bury it deep underground. That got me thinking - what would happen to it if we got it into magma, like a volcano, but instead of just tipping it in Mt Etna we dug down & put it into a deep underground magma flow? Would it burn up, at least partially, solidify underground in the rock, shoot right back up & create a radioactive volcano where we dug or just turn the lava radioactive creating radioactive rocks/volcano lava sometime in the future? Also would it be possible to do this given the pressure/temperatures involved? AllanHainey12:47, 4 May 2006 (UTC)[reply]
It can be "burned" in the correct circumstances. In a recent question, I referenced a process called "actinide fusion" - but the articles about it were too technical for me to read. Thanks to Philc for explaining it laymen's terms, I can now say that actinide fusion is, for the most part, burning up nuclear waste in a fusion reactor - rendering it harmless (non-radioactive). --Kainaw(talk)13:30, 4 May 2006 (UTC)[reply]
There is, of course, no burning involved in "actinide fusion" - at least as that word is conventionally used and as the questioner appeared to use it. Dropping nuclear waste into magma will not change the waste into a non-radioactive substance. Rmhermen16:37, 4 May 2006 (UTC)[reply]
Burning in this sense is used in a sort of slang physics way to mean a reaction that recquires activation energy, but then subsequently releases more energy, it also hot. This is an incorrent use of the term, however it is widely understood, and therefore regularly used. PhilcT+C18:17, 4 May 2006 (UTC)[reply]
I have heard it suggested the nuclear waste be reacted with silicates to make rock then dropped into a subduction zone. I have not read anything about the feasibility of this though.
At all of the places that we have access to the mantel, there is a high probability that it will come back up again relatively soon, for example hotspots, plate boundaries and volcanoes, these are likley to either spew magma onto the surrounding land, or leave it in rock form in the crust. So chucking radioactive waste, simply antognises the situation with already threatning magma now with radioactive waste. PhilcT+C18:17, 4 May 2006 (UTC)[reply]
The best way to dispose of nuclear waste is to bury it. (People seem to think that's bad because it's the same thing people have been saying for 40 years. But it's the other way around - It's still the best option after 40 years of heavy research in the field.) Anyway, to answer the question: You don't want to put it into a geologically active area because then it can escape. And the whole point of end-storage is that you don't want the radioactive materials to be dispersed. If we did, we might as well blow them out a smokestack. Also, nuclear waste is for the most part already solid. --BluePlatypus15:23, 4 May 2006 (UTC)[reply]
As a caveate, one should bury it, but where and how to best bury it are still very contentious scientific and political debates. As for the waste itself, it depends on what sort of waste you are talking about. Reactor waste is solid but wastes generated by processing plants are often liquid. --Fastfission16:15, 4 May 2006 (UTC)[reply]
It is dangerous to think that we can dispose of nuclear waste that will still be active thousands years after. In rich countries, you can pay for safety but you get a police state ; in poor countries, risks are greater and may come back to you if you go on feeding terrorism.
Cooking waste in clean nuclear plants is also risky, as costs are heavy, economic return uncertain, technology and security still immature. We use costly power (nuclear, oil) without seeing the true price. --DLL21:13, 4 May 2006 (UTC)[reply]
Note, however, that the Oklo reactor lasted intermittently on this planet for about 150,000 years, and now, 2 billion yars later, the waste from it has traveled remarkably little distance, despite geological fractures and the seepage of groundwater. (All this without, needless to say, any effort at all by human beings.) -Wiccan Quagga07:27, 7 May 2006 (UTC)[reply]
Did you have the science class on visible light? (not everyone does, since science is considered a sin in many places) White things reflect all visible light. Black things absorb all visible light. Red things absorb all but red light. Blue things absorb all but blue light. The more light absorbed, the more heat the object will absorb. Now, if you want to get very technical, it is possible to reflect ultraviolet and infrared light while absorbing all visible light and avoid so much of the heating effect, but who'd waste their time doing that to a car? --Kainaw(talk)15:06, 4 May 2006 (UTC)[reply]
Note that absorbing visible light warms a body up in exactly the same way as absorbing infrared or ultraviolet -- it's a common misconception to think that visible light doesn't warm up objects. All waves in the electromagnetic spectrum carry radiant energy, and absorbing this (which a black surface will do faster than a white surface) will warm an object up. Note also not to mix up cause and effect: It's not that an object reflects light because it is white, it is white because it reflects light. — Asbestos | Talk (RFC)15:30, 4 May 2006 (UTC)[reply]
So we see the reflected color, and thus for a black object no light is reflected. Also, we don't see IR and UV light because they don't get reflected.Patchouli17:45, 4 May 2006 (UTC)[reply]
We don't see IR and UV because our eyes can't detect them. Some other animals can see them, however. StuRat18:06, 4 May 2006 (UTC)[reply]
Keep in mind that "seeing" is only one sense. We "feel" infrared in large quantities as heat. Perhaps that is why our eyes never felt the need to see it. Also, I've read many articles that talk about a rather recent evolutionary jump that allowed humans to see blue. Before that, texts would describe grey skies and green oceans. Maybe we'll continue further along to ultraviolet. --Kainaw(talk)18:53, 4 May 2006 (UTC)[reply]
I seem to recall that in an episode of QI, Stephen Fry brought up the fact that the ancient Greeks had no word for blue, instead calling it bronze. I very much doubt that an evolutionary jump could have affected every living person since the conception of the written word however, given the date of the most recent common ancestors ( GeeJo(t)⁄(c) • 20:53, 4 May 2006 (UTC)[reply]
I remember it from many stories. One I found interesting was a period where the king wore blue because most people saw it as greenish-gray, not blue. It was assumed that the upper class could see it as blue and it was used as a test. Of course, everyone claimed they could see it as blue even if the king purposely came out in a gray robe. Then, that article argued that this may have been the origin of the "king with no clothes" story. As for the evolutionary jump, it wasn't as much of a jump as it was a progression. To this day, blue-green blindness is common (though clearly a minority). It isn't really the inability to tell blue from green. It is an inability to see blue, so it looks green. --Kainaw(talk)00:37, 5 May 2006 (UTC)[reply]
I'm sorry, but this is nonsense. 1) We don't feel infrared any more or less than we feel any other kind of radiation (IR not heat, read the darn articles). 2) Evolution has nothing to do with "feeling the need" to see different wavelengths. We just evolved to be receptive to one sub-set of wavelengths, birds and some other animals to other. 3) The idea that we had an evolutionary jump a few hundred years ago to see colors is rididculous, though having or not having a word for a color is a different matter.
See "Heat Transfer Mechanisms" in the heat article. Infrared is used to transfer heat and the human body senses infrared (and visible light) as heat. See evolution. An "evolutionary jump" doesn't happen overnight. It happens over many generations. Humans have been through many evolutionary jumps: gaining opposable thumbs, hips that allow us to walk upright, larger brains... Being able to see blue is an evolutionary jump that we are just getting to the end of. There are still many people who cannot see blue. It is nonsense to claim that people named every shade of every color on Earth with the exception of blue. --Kainaw(talk)19:53, 6 May 2006 (UTC)[reply]
I must agree with Kainaw in some aspects; while of course we can perceive infrared as heat we perceive other electromagnetic radiation similarly. Eyes cannot feel a need to develop abilities, nor does evolution work like that. There would be many difficulties with an infrared-sensitive retina; ones that come to mind offhand are the infrared emitted by our own bodies (including our eyes), and the infrared-opaque nature of some components of our eyes. In addition, I must express strong skepticism regarding the proposed recent evolution of the ability to see blue; what precisely is meant by "an evolutionary jump that we are just getting to the end of"? Even if the ablility to see blue is a new mutation, it cannot affect an entire species in this manner; it will only affect its descendants. If this mutation truly arose after recorded history, then only the descendants of that person would have this ability. For example, if it began in Europe in modern times, for instance, then no African, Asians, or any others should possess this ability. In fact, the ability to see blue is quite old; most primates have two pigments, one for a bluish color and one for green/yellow, that diverged from each other some 500 million years ago. The cone commonly called "red" developed more recently, but was in a primate ancestor, not in humans. [12] has some information on this. — Knowledge Seekerদ20:24, 6 May 2006 (UTC)[reply]
Plus, you can see a colour without naming it; Think of 'Robin red-breast' with its orange front. Seems like people just called orange things red in Britain until the orange was introduced. Skittle15:33, 7 May 2006 (UTC)[reply]
IR is related to black body radiation, in that bodies at room tempuarture emit IR radiation. Therefore, IR camaras can be used to see people in the dark, and this is often referred to as "heat sensing" cameras. This then confuses people into thinking IR is heat, which is mistaken. Also, as KS shows above, it is impossible for any mutation in recorded history to have affected everyone on the planet, as not everyone on the planet can trace their history back to a single ancestor living in recorded history. edited by me to remove unecessary rudeness — Asbestos | Talk (RFC)02:30, 8 May 2006 (UTC)[reply]
Nobody except you claimed any confusion about IR and heat. Where is your proof that humans do not have nerve cells that are excited by infrared light? That is the claim that was made. You just failed to read it in your eagerness to flame someone. Where is your proof that humans do not have a gene on chromosome 7 that was the last mutation involving human eyesight's ability to sense electromagnetic radiation? Nobody except you claimed it was a mutation that took place a few generations ago. I said that I read research papers that claimed it was still common for people to be unable to see blue in the earliest recorded history (about 5,000 years ago). But, you apparently failed to read it in your eagerness to flame someone. --Kainaw(talk)02:52, 8 May 2006 (UTC)[reply]
I'm really sorry for the post above, as I mentioned on your talk page. I'm confused as to why we're on evolution, but in answer to your questions: people don't usually ask for negative proofs. You don't ask a scientist "where's your proof that we don't have nerve cells that sense [IR light/gamma rays/dark matter]", or "where is your proof that humans do not have a gene on chromosome 7 that affects [eye sight/ultra sonic hearing/etc]". Normally people expect positive proofs: e.g. a paper that shows we have a nerve cell that is affected by whatever it is. The fact that we sense heat by thermoception is undisputed, but no one is suggesting we have IR-sensing cells. Anyway, I'm really interested in the paper you read about not sensing blue. Do you have a citation I could look up? (PubMed finds nothing). I'm confused because, as KS mentioned, we know pretty much when the blue cone cell developed (c. 500 million years ago), but I wrote my undergraduate thesis in part on whether naming colors affects the perception of colors, so it's a topic I'm interested it. — Asbestos | Talk (RFC)11:45, 8 May 2006 (UTC)[reply]
I replied on my talk page. What you said is correct. I have been plagued recently with accusations that I've said things that I haven't said. I was mainly just saying that our perception of the electromagnetic spectrum is not limited to our eyes, just as sound isn't limited to your ears when there is plenty of bass to rumble the floor. As for evolution, that is so long ago that is like another life. I really only remember the story I related. The rest of my memory is faulty. I know red/green evolved first in primates. I don't know if it is all primates, including monkeys and everything, or just the greater apes. Then, blue developed in early human ancestors. The research I as assisting (mainly by reading articles and highlighting parts the docs wanted) was in looking for a genetic cure for blue-green blindness. Since I can read Chinese, I would come in and have a stack of Chinese research papers on my desk. (Note to everyone: When someone says they can read Chinese, that means that they know the 300-500 common characters used in a Chinese newspaper or magazine, not the extra 1,000 scientific characters that are never used in common Chinese! I spent most of time with a Chinese dictionary.) I can tell you that the ability to see blue is on chromosome 7. A 'defect' in at least one gene (there was a dispute about some others) causes an inability to see blue. Then, I got off that stupid project and worked on one that used computers to detect if a song is "pleasing" or "not pleasing". I know, third-hand knowledge of a topic is rather useless, but that's all I had. --Kainaw(talk)15:25, 8 May 2006 (UTC)[reply]
The speed of light vs. theory of relativity
Einstein says that it's impossible to go at the speed of light, because the closer you get to the speed of light, you become heavier, time goes slower, and you get flatter.
But Einstein also said that speed is relative. You can't measure your speed unless you compare it to something else. When you're going 100 km/hr on the highway, what's really happening is your car is moving 100 km/kr relative to the Earth. When you calculate that the Earth is moving 1500 km/hr when it rotates, what's really happening is the Earth is rotating 1500 km/hr relative to the Sun.
The speed of light isn't relative. It is the same for all observers (see Michelson–Morley experiment). So, even if you had flied in a very fast spaceship, the light speed still would have been for you 300 000 km/s.--Ring015:49, 4 May 2006 (UTC)[reply]
The trick is that it's not that you are approaching the speed of light with respect to your own measurments of the speed of light -- your measurments of the speed of light never change, as you say. Rather, it's only using a third reference point that one can say that you're traveling at 90% speed of light. — Asbestos | Talk (RFC)17:27, 4 May 2006 (UTC)[reply]
Yes, that's exactly what special relativity is about, solving that apparent
"Going the speed of light" doesn't have any physical meaning, just as dividing by zero has no mathematical meaning. Asking "I know you can't go the speed of light, but what would happen if you did?" is like asking "What would happen if you could cut a pizza into exactly zero slices?"
-User: Nightvid(unregistered)
Well, obviously light goes at the speed of light, but that's allowed (in fact required) because it's massless. I can cut a pizza into zero slices if there's no pizza to begin with! Melchoir08:09, 8 May 2006 (UTC)[reply]
Give an example of a mechanical collision in which energy gets dissipated even in ideal circumstances, that is, where energy dissipation is unavoidable due to the law of conservation of momentum. —Masatran15:26, 4 May 2006 (UTC)[reply]
That can't happen in an elastic collision, so there aren't any examples. Conservation of momentum always holds. Conservation of kinetic energy does not. --HappyCamper17:21, 4 May 2006 (UTC)[reply]
There are two equations that together govern all collisions between two objects:
(Conservation of momentum)
(Conservation of energy)
For any collision, once you know all but two of the parameters (typically the two final velocities are unknown), you can determine everything else. What you seem to be looking for is a collision where the conservation of momentum formula forces "E" (the energy lost to inelasticity) in the conservation of energy formula to be non-zero. --Serie22:04, 4 May 2006 (UTC)[reply]
I don't know an exact example, but I think the key is that the collision shouldn't be central (or head-on), that is, that the two bodies can't collide in an elastic way because then the force would have to act on a point where the two bodies don't touch. – b_jonas12:15, 6 May 2006 (UTC)[reply]
Nothing in the law of momentum conservation prevents a collision from being elastic, regardless of whether the collision is head-on or not. A collision may be inelastic for other reasons, but not because of momentum conservation. Arbitrary username17:43, 6 May 2006 (UTC)[reply]
Aluminum fluoride
Isn't the molecular formula for the ionic compound aluminium fluoride Al3+(F-)3? I done it in chemistry today and it apparently was correct. However, according to the PubChem article, [13], it is simply AlF3. Which is correct, mine or theirs? Thanks, Kilo-Lima|(talk)16:45, 4 May 2006 (UTC)[reply]
These two formulas both reflect the fact that aluminium fluoride molecule consists of one aluminium atom and three fluorine atoms. The first formula shows additionally ions' charges. --Ring016:59, 4 May 2006 (UTC)[reply]
I would keep AlF3 and not use the ionic representation. The latter is implicit in the former if one knows that AlF3 is an ionic compound. But of course, an explanation in the article always helps. --HappyCamper17:19, 4 May 2006 (UTC)[reply]
There is not normally any need to show the charges on the ions, as the compound AlF3 can only be formed from those ions. Most likely, the reason your chemistry teacher has asked you to show the charges is to illustrate that you understand what is happening. Yummifruitbat17:24, 4 May 2006 (UTC)[reply]
The compound is only usually given as AlF3. Al3+ indicates that it is a free ion, which would usually mean that it is in solution. You do not write the redox state of ions in a compound, only for free ions. When you do need to give the redox state, it's done for the metal ion and in parenthesis. E.g. "Iron (II) oxide" is FeO and "Iron (III) oxide" is Fe2O3 --BluePlatypus20:44, 4 May 2006 (UTC)[reply]
Also, the bonding is to some degree covalent in every molecule, so using Al3+(F-)3 as a formula would be using an idealised approximation. GeeJo(t)⁄(c) • 20:48, 4 May 2006 (UTC)[reply]
What is the name of the microscopic organism that looks like a tube, and moves by bending forward, placing its head(?) down, and bringing its feet(?) up; that is, it is upside-down(?) at every alternate step? —Masatran18:00, 4 May 2006 (UTC)[reply]
A physics teacher told me about it. I don't know what it is, but it works because of the order the segments move in. If you thought about it in terms of physics without considering the solution it is in, it would seem like the creature would get nowhere, however it works becuase the fluid at this scale is very viscous. Whenever it makes a stroke, it either has the other segment streamline or out. When it makes a forward stroke, the other segment is stream line, whenever it makes a backward stroke, the other segment is down and provides drag which limits the amount of backwards motion. Looking at the picture above, it starts in the s shape. The stroke with the front segment pushes the creature backward a little, but the other segment is down limiting its backward motion. The next stroke pushes it forward, and since the creature is streamlined compred to where it was in the first position it has moved a little ahead. And no I don't know what it is called. I wish I could help more... Sifakatalk04:18, 5 May 2006 (UTC)[reply]
I have three places for my headphones to plug into the computer: one on my DVD drive, CD drive and another near the bottom of the computer, where a bit of the computer "lifts up" and there are USB ports there, too. The only place I can plug the headphones into and hear sound is from the one in the bottom. When I plug it into the DVD or CD part, near the drive, no sound comes out of the headphones. Why is this? And can I route it to the CD drive? Thanks, Kilo-Lima|(talk)18:38, 4 May 2006 (UTC)[reply]
The connection at the bottom is connected to your soundcard, while the ones on your DVD/CD drives are internal to the drives. Those two will only work when you're playing an audio cd in the respective drives, because that does not require processing by the soundcard. To answer your second question; I don't think it's possible to route the signal back to the drive. - Dammit19:06, 4 May 2006 (UTC)[reply]
Contact in sports
Which is more likely scientifically? Making contact with a Roger Federer serve or a Roger Clemmons pitch?
Those situations are so different that the only scientific way to compare them is by experiment; that is, gathering historical statistics. Melchoir19:18, 4 May 2006 (UTC)[reply]
The serve. Baseball pitches are contacted, generally speaking, about half the time. Federer does not generally have half his points via aces. — LomnTalk19:57, 4 May 2006 (UTC)[reply]
I've frequently heard that women are, in general, more suceptible to cold than men. (That is, to feeling cold, not to freezing to death.) Is this true? If so, what are the reasons for it. Thanks. -- SCZenz19:02, 4 May 2006 (UTC)[reply]
I have heard the opposite. Women have a layer of fat just under the skin which provides limited insulation.
Men have a layer of fat under the skin, too. Without it, every vein would be visible, as they are on some feet, which have very little fat.
Indeed they do, but women seem to feel the cold a lot more strongly than men, at least if the complaints by my mother and previous two girlfriends that "It's bloody freezing in here!" when the thermostat reads a fairly warm 24C have been anything to go by. I suppose it could be psychological, or have something to do with bad circulation or more sensitive skin, or it could just be that they feel more free to complain, while us macho men suffer in silence. Or it could be none of the above, and have a fairly simple explanation that I've not thought of. GeeJo(t)⁄(c) • 20:32, 4 May 2006 (UTC)[reply]
This is because women are whiners...
Put in a less technical sense, that is probably what it is. Although women produce more morphine in their body than men, they still have lower paint tolerances than men; men have a more machismo idea, that you're more manly if you can go through more pain. Women, have no such idea that they have to prove themselves like this. -- Mac Davis] ⌇☢ ญƛ.21:13, 4 May 2006 (UTC)[reply]
I'm not sure that this is related to the production of morphine by the body. That generally only affects pain reception in the short term (minutes). Whereas after I spent a whole afternoon fairly comfortable in a T-shirt in a room heated to 24C, my last girlfriend walked in in a sleeved blouse and immediately said "Christ it's cold in here! Why don't you turn the heat up?" I'd say it's more likely to be a skin issue than an internal one. GeeJo(t)⁄(c) • 21:24, 4 May 2006 (UTC)[reply]
Responders to questions like this seem disturbingly eager to chalk apparent gender differences up to female inferiority! In my experience (no more scientific than the other anecdotes people are posting), most men whine more if it's too hot than women do. Although menopause in women switches it around. --Ginkgo10020:07, 5 May 2006 (UTC)[reply]
I believe this is a simple surface area to volume ratio effect. That is, smaller objects lose their heat more rapidly than large objects. Women are typically smaller than men. Children and babies are even more susceptible to the cold, although their higher metabolic rate may compensate to some degrees. StuRat23:29, 4 May 2006 (UTC)[reply]
I cant explain it, but my (male) hands are always warm, whereas girls hands i touch/hold are nearly always cold. am I alone in thinking this? --Ballchef23:50, 4 May 2006 (UTC)[reply]
Nope you aren't alone. My hands are always cold. I agree with the surface to volume ratio idea and would also like to posit that muscle mass has something to do with it too. I have noticed the trend people with more muscle mass don't feel as cold as often. Men typically have greater muscle mass than women do Sifakatalk04:03, 5 May 2006 (UTC)[reply]
Women react to temperature stress by concentrating heat in their core body mass more so than men. This adaptation is believed to exist to help protect the uterus (and any associated pregnancy) from the effects of cold; however, it means that everything else being equal a woman's extremities will tend to get colder than a man's. I also agree that surface area to volume effects probably play a role as well. Dragons flight11:03, 5 May 2006 (UTC)[reply]
Which has the side-effect of making women better at making pastry, according to my cookery teacher. Cooler hands mean the fat doesn't melt as much when you're 'rubbing' the flour in. Skittle16:10, 5 May 2006 (UTC)[reply]
Limiting blood flow to the extremities to preserve core body heat is not unique to women, men do this, too. However, if women are more often cold, due to their higher surface area to volume ratio, then this protection mechanism will be activated more often in them. Note that this shows they really are colder, it's not just a psychosomatic issue. StuRat16:27, 5 May 2006 (UTC)[reply]
Another factor may be fat distribution. Slim men tend to have a rather even distribution of fat, while thin women tend to have fat concentrations in their breasts and butt. And, of course, evenly distributed fat provides for better thermal insulation. StuRat16:34, 5 May 2006 (UTC)[reply]
I think it might also be that when a woman feels cold, it's more likely that he will complain about it or turn the thermostat higher, while a man – even though he feels cold the same way – is more likely to ignore that and just continue work or whatever he's doing. (Or am I thinking too much in a hacker way?) – b_jonas11:59, 6 May 2006 (UTC)[reply]
Boiling point or vapor pressure?
Which is more correct 'Distillation is a method of separation of substances based on differences in their boiling points.' or ' Distillation is a method of separation of substances based on differences in their vapor pressures.' -- ∞Dbroadwell19:52, 4 May 2006 (UTC)[reply]
Offhand, and as a non-expert, I'd say they're both roughly correct, but the difference in vapor pressure is a bit more precise. In my understanding, what matters most is the difference in vapor pressures at the operating temperature of one's apparatus ; but realistically speaking, one probably designs an apparatus to take into account the entire phase diagrams of the substances. Melchoir20:10, 4 May 2006 (UTC)[reply]
Both are just as correct, because vapor pressure and boiling point are not independent properties. Another way of saying it is that the seperation is due to the differences in Activity coefficient. (lousy article, though) --BluePlatypus20:35, 4 May 2006 (UTC)[reply]
And if both are equally correct, we should use the simpler explanation, which is the difference in boiling points. That will make it easiest to understand by the widest possible audience. StuRat23:21, 4 May 2006 (UTC)[reply]
Vapor pressure increases with temperature according to a standard formula (see Clausius-Clapeyron equation). The boiling point is the temperature at which vapor pressure equals the ambient pressure (because this is when you can get bubbles of gas forming within the liquid rather than just evaporation from the surface). A substance with a larger vapor pressure at a given temperature will also have a lower boiling point. Arbitrary username14:54, 6 May 2006 (UTC)[reply]
I've made a bunch of redlinks to braking rocket; there's already an article on retrorockets. I tend to gather that a "braking rocket" is fired during reentry and landing to oppose gravity and slow the fall, while a "retrorocket" is fired in orbit to lose angular momentum and allow a landing in the first place.
Is this accurate? Is there really a distinction in terminology and/or design between the two purposes, or am I just confused? Melchoir20:24, 4 May 2006 (UTC)[reply]
Well, the term "retrorocket" generally refers to any rocket that provides thrust in the direction opposite to motion. I think "braking rocket" is just a less widely used synonym. — TheKMantalk21:35, 4 May 2006 (UTC)[reply]
According to the last paragraph of Retrorocket, "[r]etrorockets are also used in landing spacecraft on other astronomical bodies, such as the Moon and Mars". This, admittedly brief, description matches the usage I'm familiar with, and Google seems to concur. I've therefore taken the liberty of turning your redlink into a redirect. —Ilmari Karonen (talk) 21:39, 4 May 2006 (UTC)[reply]
Howdy! Why is it that immediately after coming indoors after spending some time in bright sunlight, everything appears to have a fairly strong green tint to it, that disappears after 30-60 seconds? Is there a fairly humdrum reason, or could it be something to do with the multiple ophthalmic surgeries I had as a child to correct fairly strong strabismus (two on the right, one on the left)? GeeJo(t)⁄(c) • 20:25, 4 May 2006 (UTC)[reply]
I have no idea, but I don't know if it's green tint. I spent an entire day outside in the sun only, with lots of snow, and returned to my once so very familiar school building to find myself completely amazed at how different the colours were. Highly, highly freakish. So, might not have anything to do with such an operation.
It's because of the ability of the human eye/brain to compensate for light sources with different white points: clear-sky sunlight has a color temperature of around 5000K-6000K, while incandescent light bulbs have a color temperature around 2800K (a very "reddish" white), and fluorescent lights have a white point that's completely off the color temperature scale (typically, a bluish white). However, despite the differences in the light put out by these light sources, a white sheet of paper will still look white. That's your brain compensating. You're seeing green when you come indoors because the brain doesn't adjust instantly. --Serie22:17, 4 May 2006 (UTC)[reply]
Another thought, are you wearing greenish tinted sunglasses when outside ? If so, those would block the green light and make everything appear less green. When you remove them, everything would then appear more green by comparison, until you got used to it. StuRat23:15, 4 May 2006 (UTC)[reply]
That would be reddish-tinted glasses. Greenish-tinted glasses would make everything look more green by blocking red, and when you took them off everything would look more red. —Keenan Pepper23:30, 4 May 2006 (UTC)[reply]
Well, if they reflect all green light, they would look green to others but reddish when looking through them. StuRat16:38, 5 May 2006 (UTC)[reply]
I guess that's possible, but it would be really weird. I don't think I've ever seen a material quite like that. If you put it down on a table it would look green, but if you held it up to the light, so that the light was behind it, it would look red. —Keenan Pepper01:09, 6 May 2006 (UTC)[reply]
Well, I have seen reflective sunglasses that look silver to others but like regular sunglasses when you look through them. StuRat18:47, 6 May 2006 (UTC)[reply]
Geejo, I'm going to tack a rider onto your question, because I have a question about tinting as well. Speaking of glass tint (someone brought it up! someone brought it up!), y'know that strip of blue...uh...stuff?...that's at the top of most windshields? What is that for? What's it called? It doesn't seem to do anything for glare...the windshield article doesn't mention it at all. CernenXanthineKatrena14:12, 7 May 2006 (UTC)[reply]
Name that bird
Outside my window in Charleston, SC, I see hawks circling a lot. They are rather large. The weird thing is that they are often chased and pecked at (in mid-air) by tiny black birds. The tiny black birds will pester the large hawks for a very long time. It makes no sense to me because the hawk is more than large enough to kill the tiny black birds with a single swipe of a talon. So, I wonder what kind of birds these little things are and why the hawks deal with them so patiently. Anyone have a guess? --Kainaw(talk)20:26, 4 May 2006 (UTC)[reply]
The hawk is large enough to kill the smaller birds, but not fast enough. That larger size comes at a cost of increased momentum: by the time the hawk is in position to take a swing at the smaller bird, the smaller bird is long gone. This is why most birds of prey attack by diving: the higher speed means that the target doesn't have a chance to dodge. --Serie22:20, 4 May 2006 (UTC)[reply]
I guess they are little crows (or the like). We have a lot of house finches (brown with black/beige stripes). I don't think it is them because the attacking birds are clearly black. I don't know why they attack though because there are more than enough bunnies for the hawks (and gators) to eat. Those things multiply like, well, like bunnies. --Kainaw(talk)00:46, 5 May 2006 (UTC)[reply]
I'm not very familiar with US birds so I couldn't tell you what species your little black ones are, but their behaviour sounds a lot like mobbing (see the 'in animals' section). The smaller birds see the hawks as a threat to themselves or their eggs/chicks and will engage in seemingly suicidal bouts of aerial combat (often in groups) with the predators to try to chase them away. Yummifruitbat02:28, 5 May 2006 (UTC)[reply]
It turns out that one of the doctors here is a bird expert. He pointed out that they are not just crows, they are fish crows. The differece is the smaller size, the paler beak, and the wings have a sharper point to them when it glides. According to him, they send one or two up to fend off hawks when they find a good stash of fish, shrimp, crabs... whatever. They take turns keeping the predators busy while they eat. They will also buzz-attack cats. Now, I pretty much know all of the birds around my house and office. I just have to figure out what type of woodpecker I have in my front yard. It has the head of a cardinal and the body of a bluejay. Since my yard if full of cardinals and bluejays, I joke that he is a half-breed. --Kainaw(talk)14:46, 5 May 2006 (UTC)[reply]
I don't claim to be an expert on woodpeckers, but I figured I'd do a little searching on this. Your woodpecker sounds a lot like Woody Woodpecker to me. According to this site, Woody is a Red-headed woodpecker. This species shows up on the South Carolina Breeding Bird Atlas [14]. Here's another site with pictures: [15], and another that shows their range overlapping Charleston: [16] Is that your bird, or is it much more blue? EWS23 | (Leave me a message!)17:04, 5 May 2006 (UTC)[reply]
"The head of a cardinal" makes it sound more like a Pileated woodpecker to me - this has the pointed crest on its head and the red area is restricted to the crest rather than the whole head. It is found year-round in South Carolina. Alternatively it could even be an Ivory-billed woodpecker, but if it is you're very lucky as they're thought likely to be extinct in North America. Edit: Apparently there have been sightings/possible audio evidence of the Ivory-billed in Arkansas in 2004/5. Yummifruitbat17:24, 5 May 2006 (UTC)[reply]
The head of the red-headed woodpecker is correct. It even has the darkened area around the eyes like a cardinal. The reason I'm not sure if the guy in my yard is a red-headed woodpecker is because all the photos of them have black and white bodies. This one has a blue jay body. It is blue, gray, and white. It isn't a pileated one because it doesn't have such a prominent pointed crest - just a little point. I'm sure that some day he'll be out there while I have my camera. Normally, I come home and see him fly away when I pull in. --Kainaw(talk)19:03, 5 May 2006 (UTC)[reply]
I got in touch with our local bird-expert doc again. He said that the only local bird with a red head and a blue-gray body is the red-breasted sapsucker (our article says they aren't in South Carolina - hmmm...). The picture on Wikipedia has a black and white body. Also, the one I see in my yard has a clear ring aound the neck where the cardinal head is joined to the bluejay body. So, it is probably a freak woodpecker with a blueish body or a freak sapsucker with a gray breast. --Kainaw(talk)19:17, 5 May 2006 (UTC)[reply]
While I haven't seen any pictures indicating as much, the drawings of Woody Woodpecker seem to indicate that red-headed woodpeckers can take on at least a bluish tint to their body, if not a completely blue body. Then again, maybe that was just the artist ad libbing and making something that was more appealing to the eye. Either way, it would be nice if you could get a picture at some point. EWS23 | (Leave me a message!)23:30, 5 May 2006 (UTC)[reply]
(getting a bit indented!) The National Geographic Field Guide to the Birds of North America, 4th Edition agrees that the Red-breasted sapsucker isn't found in SC. The distribution map shows it confined to the West coast, not venturing very far inland. Apparently, however, it frequently hybridizes with the Red-naped sapsucker which extends as far east as western Texas in winter. This species sometimes hybridizes with the Yellow-bellied sapsucker whose winter range includes South Carolina. The two former species were previously considered subspecies of the latter, so perhaps you're seeing some weird combination of all three! :) Yummifruitbat03:16, 6 May 2006 (UTC)[reply]
Chemical Reactions
Do all chemical reactions recquire activation energy, or are there some that have none, and will decompose almost instantaneousley in normal conditions (or even extremely low temperature) lfor example possibly something like NeCa4 or NeC2, involving noble gases (I can't imagine those compunds are to hard to pull apart). If not, what is the bond with the lowest activation/bond energy. Thank you PhilcT+C20:56, 4 May 2006 (UTC)[reply]
All chemical reactions have an activation energy. This energy can, however, be below average room temperature and many reactions occur spontaneously at 20C. A chemical reaction with no activation energy would still take place at absolute zero and since there's no kinetic movement at that point, no such reaction exists. As for the lowest bond energy, I'd say the van der Waals bonds holding liquid helium-3 together. GeeJo(t)⁄(c) • 21:27, 4 May 2006 (UTC)[reply]
Well, first we have to define "chemical reactions" more precisely, because you could even claim that two electrons near each other flying apart () was a "reaction" that certainly required no input energy. There are certainly imaginable constructs of atoms with a positive potential energy and no containing energy barriers (meaning that they will fall apart spontaneously) like XeH20 or so. Indeed, probably the reasonable definition of "molecule" in the phrase "molecule with a bond energy of ..." is "an arrangement of atoms that requires energy to dissociate", guaranteeing that all bond energies are positive. Of course, there are synthesis reactions with 0 activation energy: consider Na++Cl- NaCl. But that's not a bond energy at all. Anyway, it's certainly possible for the activation energy of a reaction (and/or the energy of a bond) to be for many T (see Boltzmann's constant), so the reaction is usually spontaneous. But any reaction with a positive activation energy (including the analysis of all reasonable molecules) can be slowed arbitrarily (though never truly halted) by reducing the temperature sufficiently. At absolute zero, were it attainable, only the reactions with no activation energy at all (like the attraction of ions or the repulsion between random non-bonded atoms like the xenon-hydrogen nonsense) can proceed, and even then they raise the temperature back to something positive. Hope this helps. --Tardis21:40, 4 May 2006 (UTC)[reply]
Not all reactions necessarily have an activation energy and it is certainly never negative. If it was, the activated complex would be lower in energy than the reactant and/or product species. So it would be a stable or metastable state and the reactant and/or products would be unstable. So by any meaningful definition it can't be negative. --BluePlatypus03:47, 5 May 2006 (UTC)[reply]
Yes and no. It's all a matter of how you define "reaction", as mentioned above. Usually, a chemical reaction is the reaction from one stable species to another, where a stable species is by definition something which is at an energetic minimum. Since you're moving between two energetic minima, by the rules of calculus, there must be a local maximum of energy in-between. (potential-energy surfaces are continuous) So for a "reaction" to have a zero barrier, it must start from a state which is not an energetic minimum and thus not be a stable species to begin with (but possibly a metastable one). As was pointed out, the activation energy can be arbitrarily small though, including smaller than kT, which means it has no significance. But even at absolute zero you could, at least in theory have a spontaneous reaction, if the activation energy was comparable to the zero-point vibrational energy of the molecule. --BluePlatypus00:15, 5 May 2006 (UTC)[reply]
As the Platypus says, the decay of excimers would be a reaction that doesn't require activation energy. When the excited state decays the molecule just comes apart. Dr Zak01:13, 5 May 2006 (UTC)[reply]
Badgersex
I've heard badgers are the species which have sex for the longest time, can anyone verify/specify? Thanks in advance!
According to here badgers can go at it for up to 1.5 hours. Can't find verification that it is the longest among "big" animals. According to this page the longest (albeit not voluntarily) coitus occurs between some insects, for up to 60 hours. (I wonder if the good folks at Google ever read their server logs to see what people search for. "Badger intercourse"...) Weregerbil10:23, 5 May 2006 (UTC)[reply]
I'm told there's a ticker at Google HQ showing some of the things people are searching for. As for how long various animals last, I've been hearing ads on the radio for some kind of impotence treatment that mentions some statistics. I'm pretty sure they mention that the mink lasts some large time, but I can't remember how long - a Google search suggests 8 hours. Confusing Manifestation12:08, 5 May 2006 (UTC)[reply]
I believe I heard the mink was able to have an orgasm for eight hours, not counting the actual intercourse.
Oh, please. Humans can do it for longer if they try. You just mix a little foreplay every once in a while in with the actual...uh...dippity doo. CernenXanthineKatrena14:07, 7 May 2006 (UTC)[reply]
Photons and EM interaction
Photon says "electromagnetic interaction is mediated by the exchange of virtual photons." Does that mean that there are constantly virtual photons exchanged between every pair of charged particles in the universe? If so, that is a lot of photons, and they last a long time. Bubba73(talk), 23:10, 4 May 2006 (UTC)[reply]
Well, they're called "virtual" for a good reason. They're not actually real, they're just possibilities of photons, which taken together average out to explain the well-known force. —Keenan Pepper23:58, 4 May 2006 (UTC)[reply]
You can think of it that way, but you can calculate the average rate of virtual photon exchange between two charged objects, and it is enormous. So yes, there are constantly photons exchanged between everything, and yes that is a lot of photons. -- SCZenz00:10, 5 May 2006 (UTC)[reply]
Yes, but I thought that virtual photons could exist for only a short time. These must exist for billions of years, right? Bubba73(talk), 00:14, 5 May 2006 (UTC)[reply]
For one thing, virtual photons can go faster (or slower) than the speed of light, so they don't necessarily take billions of years to travel between charged particles billions of light years apart. This is okay because they can't carry information. For anothing thing, it's not true that virtual photons can only exist for a short time. The only definite rule is that they can't be observed, or else they're not virtual anymore. —Keenan Pepper03:56, 5 May 2006 (UTC)[reply]
Thanks, I didn't know that. I thought they could only exist for a short time because of Delta T in the uncertainty principle. Why can't they be observed? How does a particle detector know the difference between a virtual photon and a real one? (I hope this isn't a stupid question.) Bubba73(talk), 03:40, 6 May 2006 (UTC)[reply]
salmonella
In Australia, we have a current affairs "news" show called Today Tonight. now, this show is notorious for bullshit, but i wanted to know more about it's report on salmonella. they reckon around 70% of cooked chicken availiable here has salmonella. This would infer that around %70 of australian chicken eaters would get salmonella related diseases right? of course I've never come across any thing worth believing that says our chicken is unsafe. The explanation given on Today Tonight is that our immune system will fight the salmonella, but if we keep eating the chicken eventually our system will give up. I always thought that if we fought something once sucessfully, we would become immune to it! The story focussed on a bloke who is now in a wheelchair because he ate too much chicken, but i thought salmonella just made you quite ill. I read the wikipedia article on salmonella which says "In March 2006, The New York Times reported that the US government said that 16.3% of all chickens were contaminated with salmonella". and i havent heard of huge worries in the states either.
You always assume that the raw chicken is covered with nasty buggers, salmonella being very common. That is why the official 'cooked' temperature is much higher than beef. Well-cooked chicken has no bugs, and always use a neato very geeky electronic thermometer that beeps at you! --Zeizmic02:16, 5 May 2006 (UTC)[reply]
Chicken is commonly contaminated with pathogenic salmonella and campylobacter species, as are chicken eggs. If you have ever visited a chicken farm and viewed first-hand the conditions under which poultry are raised, it should not be a surprise. Most of these disease-causing bacteria are effectively killed by thorough cooking. A good web site describing safe food practices is Safe Tables Our Priority (S.T.O.P.).--Mark Bornfeld DDS03:19, 5 May 2006 (UTC)[reply]
You should always treat raw chicken as if it is covered in poison; this is a fundamental rule of working in a kitchen. This means considering everything (hands, surfaces, knives) that comes into contact with raw chicken as contaminated, until washed. Commercial kitchens may have separate colour coded knives, chopping boards etc.; in a domestic kitchen, it is considered very important to wash hands, knives etc. once contaminated. If you take the same knife to chop up salad, there is a good chance someone will get sick. Salmonella is only one of the nasties you might find on raw chicken. Cooking is considered to destroy all of the nasties. So, there may be a grain of truth in the article, which is a much as most press reports manage. (Raw eggs are a difficult area; some things like mayonnaise need raw eggs. In practice this means that commercial kitchens take pasteurised eggs, and domestic kitchens take a chance.) Notinasnaid10:05, 5 May 2006 (UTC)[reply]
May 5
Speed of a 747 at 500 ft
My house lays just under the approach path of a major international airport. Watching the majestic 747-400s flying over my house on their final approach is a daily pass-time of mine. I just wonder: what is their airspeed at 500ft of altitude?--JLdesAlpins00:24, 5 May 2006 (UTC)[reply]
Bear in mind that I'm not a pilot and this is all speculation, but 747s are probably going really slow at this point. When they're only 500 feet above ground, they're trying to trimming back speed so that when they touch down they're just about stalling. I forget how fast that is for a 747 but my guess is like 120 mph or so. Isopropyl02:34, 5 May 2006 (UTC)[reply]
A bit of googling indicates a short approach speed of about 160-180 kts and a landing speed of about 150. Conversion of the landing speed gives 172.6 mph or 277.8 km/h. The approach speed at 500 ft should be pretty close to the landing strip I guess so the speed would be a bit above that too. - Dammit07:32, 5 May 2006 (UTC)[reply]
Shoot and Unlock
An Hollywood's favorite: a guy shoots at a lock with a pistol and the lock shatters. Would a good quality lock break apart by being shot at in real life?--JLdesAlpins00:30, 5 May 2006 (UTC)[reply]
No. Bullets are extremely fragile and locks are extremely sturdy. In the 70s (if not earlier) Master Lock ran commercials where they shot locks and showed that they still remained locked. --Kainaw(talk)00:40, 5 May 2006 (UTC)[reply]
OK. I Googled and found this site where they were able to shoot a lock off using a 12 guage slug. That is similar to using a .50 cal (which will go through a tank's armor). So, I wouldn't consider that a normal "shoot a lock and it comes off" scenario. --Kainaw(talk)00:43, 5 May 2006 (UTC)[reply]
It is nearly impossible to shoot the hasp off. It is a curved surface. Ignoring the impossible rare scenario where the tip of the bullet strikes perfectly into the extremely thin smooth front edge of the hasp - the bullet is going to turn and move off to the side with the easy-to-pass-through air and away from the hard-to-pass-through hasp. In the examples on the site that I found, the goal was to break the locking mechanism inside the lock. On that site they did mention that it is possible to slowly widdle away at the hasp by shooting it over and over all day long. --Kainaw(talk)19:31, 6 May 2006 (UTC)[reply]
Oil Production/Reserves
I'm sure this information is available on some wiki site(s), but I've tried, and I'm finding it difficult to find the precise site(s) to look for.
I would like to find out the top 10 Oil producing countries, in terms of barrels of oil per day produced, as well as the top 10 countries according to their potential production, i.e. the top 10 countries with the highest amount of petroleum reserves whether exploited or not, within their territories.
Some other pieces of information I'd be interested in would be:
1) At the current rate of consumption, approximately how long would it take to completely exhaust oil reserves (i.e. there'd be nothing left to pump) in such oil rich states as Saudi Arabia, Iraq and Iran in particular, and other states in the Middle East in general;
2) The degree to which Canada exploits its oil reserves, in relation to the degree to which these Middle Eastern countries exploit their oil reserves. (For example, if Saudi Arabia has 100x in oil reserves, and produces 1x per year, it's exploiting 1% of its oil reserves per year). What percentage of Canada's oil reserves are exploited each year? Thanks for the help. Loomis5101:16, 5 May 2006 (UTC)[reply]
We don't know to precision how much oil is really down there, and you can bet that Saudi Arabia wouldn't say the found values. They would exaggerate them considerably if they did. Template:OPEC should help as a list
This is a difficult issue, and there is not much consensus on it. See our article on petroleum - in short, oil reserves are not like giant vats which have a set quantity in them. The oil is scattered throughout rock layers, and mixed to varying degrees with other substances. Current thinking is along the lines that, for the forseeable future, oil will almost never run out, just become ever more expensive (both in terms of money and energy needed) to extract, until we reach a point (barring, or even with, further advances in technology) where the energy/money needed to extract the oil becomes greater than the energy/money which would be gained by using the oil, at which point it no longer becomes viable to extract it (see the article for details on some ideas). At which point this will happen is extremely difficult to predict, but what can be safely assumed is that oil prices will continue to rise as global demand is rising, supply is barely keeping up, and the costs of extraction are rising also.
For the same reason, you can't tell "how large potential oil reserves are", so I'm afraid all your questions (save for the one about current production, where MacDavis has already pointed you) are unanswerable. — QuantumEleven06:41, 5 May 2006 (UTC)[reply]
Top 10 oil producing countries in terms of barrels per day - this is likely to be hard to find as most frequently oil is measured in terms of oil reserves still in the ground (which, assuming its even pubicly available, is usually massively overestimated as OPEC assigns its production quotas on the basis of stated reserves) rather than daily production which is quite variable, not constant and depends on a number of factors.
Your question 1) is probably irrelevant as the current rate of production won't remain stable over time. It varies a lot now depending on capacity, demand & OPEC limits (though there is evidence that OPEC is pushing at the limits of its productive capacity). Once we get to the global oil production peak we'll be able to produce less each year (on average) - but demand will be higher than supply so attempts will be made to expand production by investing in new infrastructure/exploration, etc. This may lead to increased production in the short term (reducing the time before it is 'all' extracted) but over the longer term wouldn't make any difference. Incidentally it isn't possible to extract all the oil in any particular field, I believe due to geology about 70% is the maximum that can be extracted. The Saudis are currently, reportedly, pumping water into their Ghawar field inorder to squeeze every last drop they can out of it but they'll never take all the oil out, just all the recoverable oil which is what the reserves are based on. Technological advances could in theory increase the recoverable reserves but this is unlikely as over the past 30+ years so much money has been invested in oil extraction technology that they've advanced the capabilities of the technology about as far as it can go.
On point 2 there are a few problems, 1 - oil reserves are hard figures to be accurate on, as Quantumeleven says, even where they aren't purposefully overestimated by governments or oil companies (as Shell did with its Nigerian reserves). 2 - How do you define oil reserves, or even oil. A lot of attention is being paid to the Athabasca Oil Sands (which together with oil shale is, I think, a large proportion of Canadas oil reserves) however extracting oil from this source requires a lot of gas to be expended in the extraction process in the first place (0.4 million cubic feet of gas to produce 1 barrel of oil) and is only viable if the oil price remains high. Also as we exhaust this resource it'll take more gas to produce the same amount from oil sands until the point where it noone will bother as there won't be any money in it (or gas is running short too). AllanHainey07:55, 5 May 2006 (UTC)[reply]
Can anyone tell me what causes metabolic acidosis in burn victims? Is it caused by the loss of bicarbonate during third spacing? Is it caused by inhalation poisoning such as cyanide? Or is it caused by hypermetabolism? What is the doctor looking for when he/she orders an immediate Arterial Blood Gas in trauma/emerg? What is he/she monitoring for when he/she orders ABGs later on in ICU or acute care? Thank you for your time! Student nurse in a current heated discussion with fellow student nurse.
I understand acidosis and how it happens but not in the pathophysiology related to thermal burns.
I'm just thinking off my head so please take this with a grain of salt...but when someone is an acute burn victim, does that mean they lose a lot of body fluids? And when that happens, doesn't that shift the some sort of equilibrium in the bloodstream involving water, carbon dioxide, and bicarbonate ions? And doesn't hyperventilation do something too? I somehow don't think cyanide is involved...perhaps carbon monoxide if anything...I imagine that burn victims would be exposed to more CO gas simply because of partial combustion...from your local uninformed Wikipedian...Wait a bit longer, I know there's at least one Wikipedian out that who could probably help you... --HappyCamper04:06, 5 May 2006 (UTC)[reply]
Yes! yes! yes! All that and a little bit more... that's exactly what fluid shift or third spacing is and that is my educated opinion of what happens... the fluid shifts out of the vascular and takes the bicarbonate with it... my colleague insists it's because of SNS response and the loss of the skin's ability to insulate causing the hypothalamus to increase the metabolic system into overdrive or "hypermetabolism". While I agree this may be a possible additional additive to metabolic acidosis - I disagreed that it was the reason that ABG's are drawn immediately in ER. The third possibility is toxins inhaled during the burn incidient causing carbon monoxide toxicty. However, I have found little research anywhere to support any of these theories or even if it's a combination of them. Burnsurgery.com mentions unexplained acidosis may be due to toxicity but no where can I find it explained. --StudentNurse 10:51, 5 May 2006
Are we talking about acute burn victims just arriving at the hospital? Well, I suppose most things in science are a mixture of reasons. There might be something predominant which is important. What I'm thinking is something like
H+ + HCO3- <-> H2O + CO2
See, I'm not so sure whether fluid loss in itself would cause the blood to become more acidic. Think of it this way: you have some vinegar (we'll pretend that's the blood). Now, you pour a little bit down the sink. The vinegar left in the jar is still just as acidic as it was before. The concentration (not the absolute amount) of acid ions needs to change in order for the pH to change. But let's assume your scenario. Lots of fluid loss. Don't really know if this happens, but say the body goes into shock. Let's make it even worse. The burn wound is diseased, causing the body to go into septic shock. Does *this* cause the the production of less bicarbonate ions? If so, then the equilibrium will shift to the left, making the blood more acidic. Now, I imagine the victim starts to hyperventilate to compensate. Breathing causes the CO2 on the right side of the equation to go away, shifting the equilibrium back. I would imagine this mechanism to be part of the sympathetic nervous system. I certainly don't want to be conscious of how I need to breathe in order to regulate my blood pH! Now, as for the Arterial Blood Gas stuff. My *guess* is that it is standard routine for acute burn victims - the rationale being "let's find out how our patient is doing so we can treat the appropriately". Maybe there are IV drugs you can add to help with the acidosis or something? When the patient is in an intensive care unit, I would hope that whatever medical intervention helped bring the blood pH back to normal. If it's not normal, then additional things need to be done (and thank goodness there are people who study this!) That's my guess. So yes, it's quite possible to see that both your friend and your perspective can be go together hand in hand. But you know, I think you're right to pinpoint the bicarbonate ions first. There isn't a reason for the hypothalamus to kick in unless something fundamental in the biochemistry changes. But, I'm a rather uninformed Wikipedian - and my bias is towards the chemistry, rather than the biology :o) Cheers! --HappyCamper14:42, 5 May 2006 (UTC)[reply]
If you're still wondering: Its like any major injury, just more major: Burns leads to hypovolemia (intravascular fluid loss), leads to shock, leads to cellular hypoxia, leads to acidosis. Acidosis: related to extent of injury and duration. Recovery from acidosis indication of effective treatment. Pulmonary injury: due to burns upper airways and toxic gases lower down. Inability to breathe adequately and development of acute respiratory distress syndrome. Toxicity: HCN blocks aerobic cellular respiration, in the presence of normal oxygen tensions. CO causes inadequate oxygen delivery in presence of normal oxygen tensions and adequate hemoglobin. Both can cause acidosis, but cannot be diagnosed by routine ABGs (for CO: unless HbCO is routinely done). Later on (5 days+) hypermetabolism can caused increase CO2 production and respiratory failure (respiratory acidosis, not metabolic) if muscles are exhausted. Sepsis also a later cause for shock and metabolic acidosis. Acidosis as such, if severe, causes dysfunction of all the vital organs. --Seejyb19:50, 7 May 2006 (UTC)[reply]
Second law of thermodynamics
we have seen each law has some or other exxeptions or failure
so is there any thing in this world that does not follow 2nd law of thermodynamics.
If any body elaborate on this i will be very thank full
Don't listen to them. Wikipedia is lying here. It is possible to circumvent the second law of thermodynamics and gain energy from the vacuum. Someone even tried it, but they are silenced by the governments controlled by the global oil maffia, and the academic bigheads who don't like to be proved wrong didn't even allowed them to publish eir thesis. Now ey's alone and chased anywhere around the world and without material support he cannot build eir dream machine that would make infinite energy for free and change the whole world. :) – b_jonas11:41, 6 May 2006 (UTC)[reply]
Myes, it worries me, there are people gullible enough to believe that. Mabye you should make it more clear you are being insincere PhilcTECI22:37, 8 May 2006 (UTC)[reply]
Sujay, the second law arises from probability and statistics. Take for example the reason why you can't get heat conduction going from a cold object to a hot one. Heat conduction happens by molecules transferring energy when they collide. Now you will get some of these collisions between molecules transferring energy from the cold object to the hot object, but you will get more of them transferring heat from the hot object to the cold one because for each collision that is the more likely outcome. If we're talking about hot and cold objects which are the size of everyday things, they will contain such a huge number of molecules that statistically you can be 99.99999999999...etc...% certain that the heat will go from the hot to the cold, even if you could in principle get an exception where it goes the other way. Arbitrary username15:28, 6 May 2006 (UTC)[reply]
Eating "Instant Krazy Glue"
Today, I accidentally got half a drop of super glue on my thumb and index finger, but fortunately pulled the fingers apart before the glue dried. I have the bad habit of biting pieces of skin off my fingers and then swallowing them, so that's what I did to the fingers which had a layer of dried glue on them.
I think I ate around 0.02 mL of Instant Krazy Glue. After biting my fingers, I noticed this message on the glue container: "If swallowed, contact a Poison Control Centre or doctor immediately. Do not induce vomiting." I have two questions:
What are the symptoms of swallowing large amounts of Instant Krazy Glue?
Is swallowing 0.02 mL enough to cause noticeable effects? I would think not, unless the glue is a very strong poison (which I really don't think is the case). --Bowlhover03:59, 5 May 2006 (UTC)[reply]
I think the Poison Control Centre (you know, the one that the label told you to call) would be able to answer you. - Nunh-huh04:20, 5 May 2006 (UTC)[reply]
grr edit conflict.. Nope you are fine. I don't know what is in it and the website is completely useless, but a good rule of thumb is if kids can use it without adult supervision, it's not going to hurt. Sifakatalk04:21, 5 May 2006 (UTC)[reply]
Well, you can predict the amount of force at home! It would involve the shear modulus, which is finite even for diamond; the details depend on how far you bend it and the cross-sectional area. You can find the data here, if not on Wikipedia somewhere I haven't looked.
Perfect rigidity is a violation of special relativity. It is no more possible to have perfectly rigid body than it is to travel faster than light. Therefore, yes, all materials are bendy. -lethetalk+01:46, 6 May 2006 (UTC)[reply]
Mouse Trap cars
Does anybody know the best technique used to making a car from a mouse trap? there are heaps of websites on this topic but all are just trying to sell mouse trap car kits. so if anyone knows how to make one or if they know any good websites it would be very much apprecaited.
Are you going for speed or distance? If it is distance, the ones that use the moustrap spring to wind up a clock spring tend to go the farthest at a very slow speed. --Kainaw(talk)20:44, 5 May 2006 (UTC)[reply]
internet definition please
hello may i know the definition of internet and world wide web and their uses
(darn you for getting there faster, Dismas! :)) The World Wide Web is one part of the Internet. We have excellent articles on both: Internet and World Wide Web. If you have any questions after reading the articles, you can come back here. — QuantumEleven09:04, 5 May 2006 (UTC)[reply]
Menstrual cycles and the possibility of conception.
If my girlfriend and I had unprotected sex on the evening of March 6th/morning of March 7th, and her cycle started March 4th and apparently ended March 6th, is it possible that the aforementioned unprotected sex resulted in conception?
If it did result in conception, and unless there were an early miscarriage, she would be in about her ninth week, and an over-the-counter pregnancy test would tell you for sure. --Ginkgo10023:15, 5 May 2006 (UTC)[reply]
speed of light
what happens if one travels at the speed of light? I know its impossible but i want to know
(Grr!!! Edit conflict!!!!) Your mass will keep increasing until it becomes infinity when you reach the speed of light. And you would stop moving because you would need infinite amount of energy to keep you at that speed. . But in short, we dont know what will happen because noone has ever travelled at the speed of light. I'd suggest you to read [this as it answers your question to a certain extent. Check back if you have anymore doubts. Jayant,17 Years, India • contribs10:18, 5 May 2006 (UTC)[reply]
I'll modify an answer I gave at Talk:Speed of light. First of all, yes, it's impossible. That said, if you do accelerate to the speed of light, in your own reference frame, the very same instant you achieve that speed you will simultaneously slam into your ultimate destination, no matter how far away it is. If you like, this result is time dilation in the extreme; for every second that passes in someone else's reference frame, you experience 0 seconds. Since you can't pass time while cruising at the speed of light, you can't perform experiments or make observations, so in some sense, nothing happens.Melchoir10:25, 5 May 2006 (UTC)[reply]
Pardon my ignorance/scepticism, Melchoir, but if it's impossible then ... it's impossible (even for all-powerful beings such as yourself). You could accelerate as arbitrarily close to the speed of light as you like, but you could never reach it. Therefore there would never be such an instant as you describe. Unless it wasn't really impossible after all. This sounds a bit like "You can never count to infinity, but if you could, the number would be <xxx>." JackofOz10:51, 5 May 2006 (UTC)[reply]
You're right of course, but with some effort I could probably defend my interpretation. As in, draw a smooth, mostly timelike world line with a lightlike section included, parametrize it by proper time, and interpret that as someone's history of experiences. Sure, there are continuity problems, and it's kinematically forbidden for a massive particle to actually follow the path. But if you interpret the math liberally, what I said makes some kind of sense. Melchoir11:04, 5 May 2006 (UTC)[reply]
I think it's perfectly reasonable to take your description of travelling along a lightlike path as simply what it's "like to be" a photon or other massless particle. I know some people don't like ascribing imaginary experiences to non-conscious POVs (to the point that many Wikipedia articles are less clear than they could be to avoid the issue), but I personally have less trouble imagining the perspective of something that cannot possibly be sentient than swallowing local portions of globally forbidden worldlines and what have you. --Bth11:25, 5 May 2006 (UTC)[reply]
I think the best way to understand Melchoir's comments is as a limit. The correct description of what happens as you increase your speed becomes arbitrarily close to what Melchoir describes. The length of proper time to reach your destination becomes arbitrarily small, etc. -lethetalk+01:44, 6 May 2006 (UTC)[reply]
That confuses some people, though, due to the conflicting meanings of the speed of light. It isn't possible to travel faster than 186,000 mph (c, the speed of light in a vacuum), but it is possible to travel faster than the speed at which light travels through some materials. Even then, you might say that the "light" (photons) doesn't really travel any slower. - user:rasd
I would like to know how lighting fittings are manufactured. The process involved from sourcing the materials used to the final product. i would be grateful if the information could be broken down to specific lighting fittings. Also the what are the references of regular bulbs to low energy ones.
Why cant a plane mirror and a highly polished white surface produce reflection of the same kind?
Well, a white, shiny car is white. It has been painted white, and so it is only natural, indeed demanded, that it's most dominating reflection is white. This is because of pigments that WILL suck up light on certain frequencies, and reflect light on other frequencies. Thus, seeing yourself in the mirror image on a white car hood, you see yourself in shades of white, because all other colours are absorbed. A plane mirror is not coated with such pigments, unless artificially added, and reflects nearly all frequencies. I think most plane mirrors, when cleaned very well, can produce as much as 70-85% reflection. Thus, plane mirrors DO suck up some light, you just don't see it very well. 213.161.189.10713:08, 5 May 2006 (UTC) Henning[reply]
Er, white light is made up of all (visible) frequencies ...
The difference between a mirror and a general white surface is smoothness. A smooth surface like a mirror will give specular reflection, but light hitting a rough surface will be scattered at different angles depending on which particular little part of the surface it hits -- diffuse reflection. --Bth13:55, 5 May 2006 (UTC)[reply]
So basically, a highly polished white surface will no longer be white; it will reflect like a mirror if you polish away all the surface roughness. Neh? Skittle16:26, 5 May 2006 (UTC)[reply]
If you ask someone what color a mirror is, don't they say "silver"? So, I think a highly polished silver car would have the effect of a mirror. --Kainaw(talk)19:56, 5 May 2006 (UTC)[reply]
No, a white surface will never become a mirror no matter how long you polish it. The difference is that a shiny white surface has a transparent coating and then a microscopically rough white surface underneath. Some of the light reflects off the outer surface, forming the reflection, but most of the light passes through the transparent layer, is scattered off the white surface, and passes back out in a random direction. In a mirror, both outer and inner surfaces are microscopically smooth, so they both produce reflections. —Keenan Pepper01:00, 6 May 2006 (UTC)[reply]
Yeah, I've always thought of mirrors as silver, and shiny silverness as mirror-like. Any color material can be made reflective, by reducing scattering of the light (polishing it), but anything reflected in it would appear really red/blue/whatever, like looking through a color filter. What exactly is the color silver, in terms of the additive spectrum? Black Carrot22:19, 5 May 2006 (UTC)[reply]
A reflective red surface would look red (or "metallic red"), a reflective blue surface would look blue (or "metallic blue"), and a reflective white surface would look silver (or "metallic white"). True silver color is the same as white, as I understand; the difference is the degree of reflectiveness. --Ginkgo10023:18, 5 May 2006 (UTC)[reply]
Last night (may 4th), I was in a play. Right before I heard my cue line I was feeling really nervous. I also had some "butterflys" in my stomach. What I was wondering was what are these called (the butterflys) and why do they feel like that. I already looked at the article anxiety but to no avail. I was just curious. THanks. schyler11:53, 5 May 2006 (UTC)[reply]
While I also learned a new word, it didn't really answer my real question. What is the name for the butterflys, not the name that butterflys is a symptom of. Thanks though. schyler12:16, 5 May 2006 (UTC)[reply]
It seems that butterflies (pedantic note: remember -y pluralises to -ies in most cases) is what it's called. Certainly, our Butterflies in the stomach article doesn't give an official name and even a rather worthy article on thePhysiology of the Stress Response doesn't use any other term (it explains it as a reduction of activity in the digestive system as a response to stress, if you're interested; on the other hand, this article claims it's the result of a second brain in the stomach. We report, you decide.) --Bth12:34, 5 May 2006 (UTC)[reply]
Your stomach (and esophagus, small intestine, and colon) contains brain tissue. It functions like a normal brain, just small in comparison to the brain in your head. When you have a sudden fear, the brain in your head releases hormones to prepare the body to fight or flee. The sensors in the lower brain pick those up and charge up for action. The charging and discharging of all those sensors is what the brain in your head is picking up as butterflies. --Kainaw(talk)12:53, 5 May 2006 (UTC)[reply]
Ahhhh, I made the mistake of skimming the top of that article and thinking it was a joke. (I still think it's a misleading use of "brain"; by that standard the spinal cord is a brain too.) --Bth13:48, 5 May 2006 (UTC)[reply]
The spinal cord is not capable of making decisions and controlling parts of the body on its own. The brain tissue in the abdomen is. That is how a person with a completely severed spine is still able to have a functioning digestive system without input from the brain through nerves. Of course, the hormone communication between the brain and the rest of the body continues to function - but going in to that is just too technical for the question a bout butterflies. --Kainaw(talk)14:27, 5 May 2006 (UTC)[reply]
D'you know, it'd never even occurred to me to think that there might be a problem with digestion for spinal cord patients -- very interesting.
Automatic and reflex actions are controlled in the brain stem. You could argue that the brain stem is the top of the spinal cord. You could say it is the bottom of the brain. Either way, it is completely different in structure than the spinal cord. --Kainaw(talk)14:55, 5 May 2006 (UTC)[reply]
Reflex arc claims "A reflex to a stimulus is almost simultaneous, as the reflex arc doesn't involve the brain at all." Does it need correcting? --Bth16:03, 5 May 2006 (UTC)[reply]
That is the difference between a brain stem reflex (ie: burning your elbow and jerking your arm - which most reflexes are) and a reflex arc. There are many reflex arcs in the body and they do not all go through the spinal cord. For example, loud noise causes an acoustic reflex arc in the eardrum which constricts the stapedius muscle. A hiccup is a reflex arc but I don't remember the exact nerve that triggers the diaphram to contract. Regardless, it is a reflex arc. But, reflex arcs are controlled by neurons. They are hard-wired connections from a receptor (usually a nerve) to a reactor (usually a muscle). Trigger the nerve and the muscle contracts. So, because the spinal cord is a conduit for nerves, some of which traffic reflex arcs, does not put it anywhere near the classification of neuron formations in the digestive tract or brain. --Kainaw(talk)17:01, 5 May 2006 (UTC)[reply]
Since I was dissed, I have to go back to the original question. I looked up stage fright and that led me to that fancy name. I always thought that butterflys (ies?) was the only symptom. What we have found out is that there is no Latin name for 'butterflys' alone, except 'weird reaction by your second brain - itis'. (Geez, I feel like ol' Noti!) --Zeizmic17:35, 5 May 2006 (UTC)[reply]
Welcome to my world. I am a computer programmer working in a building full of doctors. I mention that I have a bump on my finger - a wart to any normal person. They spit out a bunch of weird latin words. Also, they ask for data reports on things like "hypercholesterolemia". What's that? High cholesterol to any normal person. If it wasn't for wikipedia, I'd never get by when asked for things like "nephropathy" or "gfr scores". On the flip-side, I got a shipment of 12 optical mice in. I sent out an email asking which doctors didn't have an optical mouse so they could be replaced. Most responded asking what an optical mouse is. --Kainaw(talk)18:03, 5 May 2006 (UTC)[reply]
English not providing you with all the features you need? Don't dispair make it up. If you want a pseudo-Latinate word for that squirty feeling, try combining some of these funky elements:
Unfortunately most of these are suffixes but I quite like ventrolepidopter and I would tell people about them if I did not have them. Bonus word of the day borborygamiphobia, fear that someone will hear your stomach rumbling. MeltBanana16:05, 6 May 2006 (UTC)[reply]
Nuclear bombs in phase
I heard a nuclear bomb has an energy efficiency of about 3%. Would this be increased if we divided the bomb's mass over on ten (or hundred) smaller, identical bombs, and set them off so that the blast waves were in phase upon hitting the target? For some reason I don't think that's what energy efficiency truly means, so does anyone have a better word for what is actually increasing? Scientifically correct, that is. "Blast effect" sounds a bit too... Star Trekish, but if that's the word, I'll go along with it. I just need to use correct terms. Thanks! 213.161.189.10713:31, 5 May 2006 (UTC) Hen[reply]
Don't nuclear warheads already consist of several mini-warheads that spread out - each one capable of hitting a separate target or surrounding and increasing damage on a single target? --Kainaw(talk)14:57, 5 May 2006 (UTC)[reply]
What you are basically arguing for is instead of having one 20 kt bomb, to instead have two hunded one ton bombs. That's obviously possible but completely defeats the entire purpose of nuclear weapons, which concentrate a large amount of energy in a very small amount of space (relatively speaking). There are, though, arrangements (again, see MIRV) where you can distribute the yields at bit — ten 300 kt bombs can do a lot more damage than one 3 Mt bomb, if they are arranged so that the borders of their blast zones are touching. See effects of nuclear explosions for more information about how increased yield results in much less damage efficiency because you are essentially increasing the volume of a very large sphere, rather than spreading out the damage along a single plane, if that makes sense. --Fastfission15:29, 5 May 2006 (UTC)[reply]
In any case, nuclear weapons are more than destructive enough, "inefficient" or not. Extra destructive efficiency is hardly a priority; in fact, existing weapons, even, say, a 1 kiloton jobby that a first-time nuclear proliferator could construct out of reactor plutonium, are effectively too destructive to be of any use other than deterring other people from using nuclear weapons on you (or as a terrorist weapon).
What *would* be militarily useful would be a nuclear bomb that weighed 25kg, had the explosive potential of 10 or 100 tons of chemical explosive, didn't produce fallout, and whose lethal prompt radiation dose didn't extend beyond the blast radius (so everybody who would die from radiation effects is instead killed instantly by the blast). Thankfully, such a weapon doesn't appear to be possible, because the temptation to use it would be so strong I don't imagine the country that perfected the device would have been able to resist using it in their next conflict. --Robert Merkel22:04, 7 May 2006 (UTC)[reply]
To address the "energy efficiency" question, that's something completely different than what you're asking about--it's not a question of what percentage of energy released is absorbed by the target, but rather what percentage of the theoretically possible yield is actually generated.
Nuclear weapons consist of a quantity of fissile material. You can mathematically calculate the energy which would be released if every single atom of the material underwent fission; but the actual energy released by a weapon is quite a bit less. It seems that the issue is that you have to have a minimum amount of material (the "critical mass") together to make an explosion, so a weapon has that much material, but normally kept in a configuration where it doesn't detonate--multiple pieces, or a hollow sphere, or something like that. When the weapon is set off, it pushes everything together so that a chain reaction becomes sustainable--but the energy of the explosion itself blows the material apart before the chain reaction is complete, and a significant portion of the material does not undergo fission.
In any case, it seems that the 3% figure you heard is too low for most weapons. The nuclear weapon article states "The efficiency of a fission weapon is the fraction of the fissile material that actually fissions. The maximum is ca. 25%. For Fat Man it was 14%, for Little Boy only 1.4%." Chuck18:56, 8 May 2006 (UTC)[reply]
Extrusion of Polycarbonate
If polycarbonate is not dried before it is extruded, will the mechanical properties such as impact strength be degraded as it goes through the extrusion process. If so how large is this effect and would it be more cost effective to dry the material and extrude it or just extrude it without drying.
Censorware
The computers at my school (OS 9 iMacs) have all their internet traffic filtered at the server, so I need a method to bypass the filters? Basically, what I think I need is a proxy that does data encryption. Any suggestions?--Frenchman113 on wheels!18:52, 5 May 2006 (UTC)[reply]
Well, if you're really looking for marijuana info and not pr0n, you could try searching for it on Google, then clicking the cached link. That's always bypassed the blocks at my school. It doesn't give pictures, though, just text, with your search terms highlighted. Alternately, you could use [17], a proxy a friend of mine made that works reasonably well for most things. Black Carrot21:42, 5 May 2006 (UTC)[reply]
Not necessarily, but it can be argued that since 1) the school is paying for the connection, and 2) it has intended it for (what it defines as) educational use, it has the right to filter content. This doesn't stop the user in question going elsewhere to access the sites s/he wants to access - at home, or in an internet cafe. — QuantumEleven09:31, 6 May 2006 (UTC)[reply]
Why don't you talk to the school IT person? If you need to get past some filter and have a good reason, then they should be able to assist you. Otherwise, bypassing the firewall would be something that could get you into a whole heap of trouble (not just inappropriate content, but malware could slip by.) Andrewjuren(talk)09:38, 6 May 2006 (UTC)[reply]
Sure you didn't. Did my suggestions work? If they did, and if you do decide to follow your instincts, I know another trick that might help: the Google image search is, as far as I know, pretty difficult to block. It is actually possible, in my school, to view thumbnails of hardcore porn, but not to look up the Nazi party (a real third party in America) for my AP Government report, without using a proxy. Black Carrot16:15, 6 May 2006 (UTC)[reply]
If the school's censorware makes researching your homework impossible, maybe it's time to talk to the teacher who gave you that homework and have her talk to the school's IT personnel. You could also try researching using books. That would avoid all the internet censor stuff. - Mgm|(talk)14:59, 7 May 2006 (UTC)[reply]
Water flow
I need to get a water flow of 100 liters/minute through a 12.5 mm nozzle. I will be pumping this from a 200 gallon tank at floor height through a short length of standard garden hose and out through the nozzle. I must pump this volume for a period of three minutes. I am trying to figure out what to use as a pump. I tried a standard sump pump that advertised a flow rate of 8600 gallons per hour but found my flow rate out the nozzle well short of the requirement I must meet. Do you have any suggestions? --12.19.235.3418:58, 5 May 2006 (UTC)[reply]
When you're moving current no matter if its water or electricity, if you squeeze a large amount of it together then open it up in the direction it is going,it boosts the current. If you use a wider hose than a standard garden hose, more water will be putting pressure on your nozzle. This will increase the water pressure that is exiting your nozzle because the water has more space to move. Think of it as popping a paper bag. When you fill the bag with air it all wants out because there is too much pressure so it blows a hole in the bag. Your nozzle will act like the hole and release all the pressure. If that doesn't work you might need to consider a bigger nozzle.
Because you are looking for a short duration, you can go with a cheaper pump and a more expensive (sealed) tank. Pressurize the tank and then release the pressure through the nozzle. Then, it doesn't matter how fast the pressurizer pumps. The drawback is that you'll get a rather short period of steady pressure that dies off quickly. All in all, it is just like those super-soaker water guns. --Kainaw(talk)19:37, 5 May 2006 (UTC)[reply]
I'm pretty sure you are talking fire-hose volumes here. Your sump pump could only do 2 gal/m or 8 L/m. City pressure at 40 psi might only get 12 L/m through a standard hose. You want another order of magnitude more than that. --Zeizmic20:37, 5 May 2006 (UTC)[reply]
Pump are designed to deliver either a large volume of water at low pressure, a small volume of water at high pressure or some trade-off in between. When you purchase a pump it will often have a small table listing how many gallons per minute it will deliver at a certain pressure. You can estimate the pressure required at the nozzle to give you the required flow rate using the firefighters formula: gallons per minute = 29.7 x diameter in inches squared x square root of the pressure in pounds per square inch.
So you need around 14psi at the nozzle to flow 26.4gpm. That is if you are using a tapered smooth bore nozzle--if you are pumping directly out of a 1/2in pipe the pressure required will be slightly higher. You also need to take into account your "short length of standard garden hose". Trying to move 26.4gpm through a full 3/4in inside diameter hose you will have about 60psi friction loss per 100 feet of length[18]. Standard 3/4in or 5/8in garden hose will be even worse. You will need a pretty large centrifugal pump to push that amount of water through any length of small diameter hose like that. (Forgive all the non-metric units, i'm too lazy to convert them.) EricR01:18, 6 May 2006 (UTC)[reply]
Electrical Grounding
I was wondering how it could be that a pole in the ground serves to conduct electricity to 'earth'. I mean, the concrete or soil or whatever it is that the pole is inserted into, isn't going to be electrically conductive is it? If I rectified mains electricity, and connected the negative terminal to a pole in concrete, wouldn't the pole just fill with enough electrons to eventually stop the current? --Username132 (talk) 19:49, 5 May 2006 (UTC)[reply]
You are correct. Just any old ground won't work. In 29 Palms CA, Kuwait, and Turkey, we had a hell of a time keeping ground grounded. We had to keep pouring water on it. In Turkey (since there were only 3 guys deployed), we made the ground post our pee hole. Water helps move electrons to the ground rod and keep a good supply of them ready for usage. --Kainaw(talk)19:53, 5 May 2006 (UTC)[reply]
Depending on the use, 'grounds' or poles in the ground, whatever you like to call them, are usually attached to the water piping that supplies the building which I think is copper, and anyway, grounds are generally their to serve as a better conductor than the alternative, eg you or furniture, therefore preventing fires, there use is not really to complete a circuit. Plugs generally have three prongs, the live, neutral and ground, the live and the neutral are the circuit, the ground is used if the appliance has a meatl outer casing, if through faulty wiring etc. this casing becomes live the ground/earth wire is a better conductor than you, so that should you touch the appliance you wont become the unlucky link to the earth. So however poor conductors the grounds are, as long as their better than the alternative, it doesn't matter. PhilcT+C21:47, 5 May 2006 (UTC)[reply]
And hopefully as soon as the live touches the earthed casing, it should trip the fuse or circuit breaker anyway. Typically this will require the earthing to take a number of amps, but if you have an RCD breaker then even a few tens of milliamps to earth should trip the breaker. Arbitrary username18:23, 6 May 2006 (UTC)[reply]
Wikipedia on DVD-RW
How possible would it be to have wikipedia on a DVD-RW that was able to update itself when put into a DVD-RW drive on a computer with internet access? How long would it take to make such a thing happen if you knew how to program? When can I expect to see self-updating Wikipedia on DVD-RW? --Username132 (talk) 20:31, 5 May 2006 (UTC)[reply]
On a DVD-RW would technically be possible, but not advisable given the limited amount of times it can be rewritten. But if you really wanted it'd be a pretty easy task. In fact, it might be possible with hardly programming anything since the sourcecode to wikimedia is available and so is the database which holds the articles. Basically you could run a webserver with php support and a database engine from the DVD-RW and you're done. - Dammit20:52, 5 May 2006 (UTC)[reply]
Note that, depending on what you want on your DVD, the amount of content on Wikipedia may be too big to fit on one disk. For instance, including all the images is an extra 76GB. Read all about it at Wikipedia:Database download. — QuantumEleven09:27, 6 May 2006 (UTC)[reply]
Time consistancy theory??
What is the name of the space-time theory where all three time-periods (Past, Present, and Future) are all occuring at the same time? That is to say, as I sit typing this, I also sit thinking it up, and sit drinking my coke after submitting. Thanks! Here7ic20:41, 5 May 2006 (UTC)[reply]
Well I don't suppose you're talking about Multiple World? If so, that wouldn't really be a fitting description. But then again it really doesn't sound like MW. I'll be waiting for a better answer, this sounds interesting. :)
In special relativity, the time-ordering of events can depend on the reference frame that you're in, for events which occur far enough apart in space that you would have to travel faster than light to get from one to the other (known as a "space-like" interval). But the three events you describe are all in the same place (separated by "time-like" intervals), so the time-ordering is the same in all reference frames, and anything that says otherwise is probably sci-fi. See special relativity#Causality. Arbitrary username15:43, 6 May 2006 (UTC)[reply]
Nucleus and cytoplasm
This is probably a very simple question, but it occurred to me while doing some reading today. We know that one can remove the nucleus from one cell and replace the nucleus in another cell (somatic cell nuclear transfer) and it will (if you are lucky) develop normally. Does this work if the two cells are from different species? I imagine it would not work between animals and plants since their cells contain different organelles, but what about animals with high degrees of relatedness (i.e. a chimpanzee and a human)? Has anything like this been attempted (I assume not with humans, of course, but dog/wolf wouldn't surprise me if it had)? If not, should it work? --Fastfission22:36, 5 May 2006 (UTC)[reply]
Note the last sentence in the somatic cell nuclear transfer article: "Not all of the donor cell's genetic information is transferred. DNA of organelles (mostly mitochondria) is left behind, with the resulting cells retaining those structures which originally belonged to the egg." I think this would be the main factor that determines if it will work cross species, the mitochondrial DNA would have to be compatible for it to be possible. I'm not a biologist though, so it's only a guess. - Dammit23:57, 5 May 2006 (UTC)[reply]
That's a good question. I suspect not, but for very closely related species I can't be absolutely certain. I'll also note that SCNT is extremely traumatic for cells even when you're working in the same species.
Note that if it did work, the effect would 'wear off' as the host cell would start synthesizing proteins as specified by the transplanted nucleus. After a cell division or two you'd be hard-pressed to find any trace of the original host; all of the proteins present would be those specified by the transplanted nucleus' DNA.
The exception would be in the mitochondria, as mitochondria have their own DNA that's replicated and handled separately from the genomic DNA in the nucleus. In principle I suppose that you could have a human cell with chimpanzee mitochondria, say. To achieve that end result, it might be easier to transfer mitochondria than to swap nuclei, however. TenOfAllTrades(talk) 00:06, 6 May 2006 (UTC)[reply]
Though it seems to happen often enough in movies and is commonly used as an expression, is it plausible that a large segment of the human population would react to extreme fear by experiencing incontinence (either fecal or urinary). My understanding is that strong anxiety makes it dificult to urinate, so if anything, people who are scared should find it near impossible to urinate, and not the other way around (I assume the same rules apply to defecation). To be blunt, which is the more plausible outcome, being "scared shitless", or "shitting your pants"? --Aramգուտանգ03:46, 6 May 2006 (UTC)[reply]
Funny how in "24", they never go to the bathroom... Anyway, strong anxiety can certainly take your mind off going to the loo, and this, I would say, is more likely than being scared so much that you actually piss yourself unintentionally. It sounds like a climbing ladder, and the first is more frequent than the other. I mean, you'd have to be REALLY scared, shock-scared, to immediately shit your pants. Either that, or go a long, long time in controlled anxiety.
I couldn't say, but your last sentence is mistaken. Being "scared shitless" (which, incidentally, redirects to fight or flight response) means you no longer contain any, as it's all migrated downwards. Strong anxiety does make it difficult to pee in a public restroom (if that's what you mean), but my experience is that that's performance anxiety, and as such, stands in the way of action of any kind. Mortal terror, which is what it's supposed to be connected to, is rarely experienced in a bathroom outside of psycho-thrillers. I don't know how people really respond to extreme fear, having never seen it happen, but if it helps, the rationale I've heard for why it happens in animals (assuming it does) is that to run as quickly as possible, they have to lose as much excess weight as possible. Black Carrot16:09, 6 May 2006 (UTC)[reply]
I'm guessing the defecation and urination fear response is a protection mechanism against predators. That is, once you do that, you no longer smell like food to the predator, so it might let you go. Our instincts might be sufficiently vague that any extreme fear causes this, however, not just predators. I recall a nice pick of a bungee jumper with an impressive brown streak up the back of his shirt (he was upside down, of course, when this happened). StuRat22:01, 6 May 2006 (UTC)[reply]
I don't know for certain about extreme fear (though I have no reason to doubt that it's a real response), but severe trauma can definitely causes incontinence of both types. --Ginkgo10023:04, 6 May 2006 (UTC)[reply]
Well, the losing weight and predator repulsion explanations make sense, but what I'm really wondering about is whether people actually piss/shit their pants when they're scared in real life. Since paruresis is caused by anxiety, it doesn't matter if it's anxiety caused by fear, or performance anxiety. Are there any documented cases of people experiencing incontinence when scared, where fear is the only cause for it, i.e. they haven't been holding it in for a long time, or they haven't found themselves suddenly to be in freefall. Also, is there a term for it that's better than "fear-induced incontinence", because this is a difficult subject to search for without key terms. --Aramգուտանգ00:45, 7 May 2006 (UTC)[reply]
I can assert, through personal experience, that a person in imminent danger of drowning (surely, a situation involving real fear) can defecate involuntarily. It happened to my daughter, then 13, before I and my brother-in-law rescued her.G N Frykman17:43, 8 May 2006 (UTC)[reply]
The Neutral Wire.
The 3 wires that run to my house from the power lines are two hot and one neutral wire. The ground wires in my home electrical system are connected literaly to the earth via a ground rod which runs a certain number of feet into the ground. My questions refers to the neutral wire. When I plug a lamp into an outlet, the AC voltage moves back and forth 60 times per second, and electrons flow back and forth through my lightbulb giving up their energy as light and heat, and in turn this voltage is running through the neutral wire as well - does it run all the way back to the power station? Is it connected to a huge ground rod? Why can't I just use my ground as a 'neutral' wire? Aren't some neutral wires actually attached to the ground buss in the panel? (Not in Canada)
If anyone can help me understand this, I'd appreciate it.
I wish I could give you a better answer, but I do know that the electrons in your wiring actually move very slowly, only a few meters per second and not nearly the speed of light as many people believe. Furthermore, although your ground at home may act okay as a neutral sink for electrons, I think that most houses don't have good enough ground to act as the "neutral" wire. Additionally, it would cause pretty nasty shock if you were to walk by it, not to mention potential radio noise. I would recommend reading our article on Electric power transmission, and related "See also" articles. Andrewjuren(talk)08:48, 6 May 2006 (UTC)[reply]
Yes, it runs all the way back to the power station via the earth. There is so much mass of "earth" that it forms a very good conductor. Although you can connect an electrical circuit directly to earth, this is not a good idea as you need a very good, deep, solid connection. This is precisely what the supply company provides with their "neutral". I suggest you read our article on ground and neutral. --Shantavira09:03, 6 May 2006 (UTC)[reply]
Yep, that's true, but just a point of note, that your power company probably provides three-phase electric power. Although each individual household will generally just be on one phase, the current that you (and others on the same phase as you) draw from the live cable approximately balances out with other households that are on the other phases, so the amount of current that actually has to run back down the neutral all the way to the power station is much less than you'd first think. Arbitrary username15:52, 6 May 2006 (UTC)[reply]
The nuetral wire and live wire connect to the Generator, the earth wire is for safety. In the UK ans such countires, where laying vast amounts of power lines is not a problem, because the country is no that big, the current is not returned to the powerstation via the ground, which is done in some countries, it just goes back down the nuetral wire and completes the circuit. PhilcT+C09:18, 7 May 2006 (UTC)[reply]
Fat absorption
I've seen a few books and web sites out there that say that the humans cannot absorb more than 10 grams per hour of fat from the GI tract. Where does this come from, and what type of experiment (if any) was done to determine this? Experiments which I have undertaken on myself seem to suggest otherwise. -User: Nightvid(unregistered)
Well, it takes bile to break down fats into a form that can be absorbed, and this takes time, and, of course, bile. That rate doesn't seem all that slow to me; if food stays in the proper portion of your digestive system for a day, that's some 240 grams you can absorb each day. Since there are 9 calories per gram of fat, that makes 2160 calories per day from fat. That's plenty of calories per day, even if you don't eat any protein or carbs or consume any alcohol. I suppose any undigested fats which leaves the system would cause diarrhea, however. StuRat21:50, 6 May 2006 (UTC)[reply]
Why is yawning contagious between different species?
I yawn, my parrot yawns.
My parrot yawns, I yawn.
I see a dog in the street yawning, I yawn.
I yawn near my mother's cat, my mother's cat yawns.
etc.
Why can a yawn be transferred from species to species like this? I've read the yawn article and it mentions that it can be 'interspecific' in it's contagion but it doesn't explain why. Anyone know? Thanks.
This is from my shaky memory, so I can't guarantee 100% accuracy, but ISTR that t's a survival mechanism. Yawning is a way of increasing the oxygen uptake in the body. As such, it also aids alertness by increasing the oxygen getting to the brain. It makes sense that if one person/creature yawns then either (a) the oxygen level may have dropped slightly, or (b) there is some need for the person/creature to be alert. In both cases, it would be a good survival heuristic for other nearby people/creatures to also yawn. It's not a conscious decision to yawn in these instances; it's a natural response to the surroundings ("surroundings" in this case also including other nearby animals/people). As with other good survival heuristics, they tend to increase the chances of an individual's survival and... well, see evolution if you want to take that train any further. Grutness...wha?13:34, 6 May 2006 (UTC)[reply]
No, yawn says, "A long-standing hypothesis is that yawning is caused by an excess of carbon dioxide and lack of oxygen in the blood. The brain stem detects this and triggers the yawn reflex. The mouth stretches wide and the lungs inhale deeply, bringing oxygen into the lungs and hence to the bloodstream. It is almost certain however, that this hypothesis is not correct. One study..." Black Carrot14:55, 6 May 2006 (UTC)[reply]
The consensus among people whos study this stuff seems to be that yawning really is contagious. A reasonable explanation, it seems to me, would be mirror neurons, neurons that respond to behaviors observed in others by performing exactly the same. (This explains why you wince also when another person steps on a thumbtack. However, the first Google result for "yawning contagoius" claims that a 2005 study using fMRIs found that the mirror neuron system was inactive when viewing videos of other people yawning. That would seem to indicate that some other system is at work, though probably still one that does depend on some degree of social and self-awareness as humans and chimps are the only species believed to exhibit contagoius yawning. If you want a slightly longer answer without having to wade through the scientific articles, you might want see this guy's blog. BTW, the result of that Mythbusters segment was "CONFIRMED," if you were wondering.
-Wiccan Quagga05:09, 7 May 2006 (UTC)[reply]
Immunity to self-produced toxins
Well, this may be a stupid question, but as the saying goes... How is it that animals who produce toxins are typically immune to them? I understand how, from an evolutionary POV, it's obviously beneficial for an animal not to be susceptible to its own species' toxins, but I was wondering how this is typically accomplished. How are scorpions who secrete neurotoxins not affected by them, for example? Do they have substances in their blood which break down the specific neurotoxin they use before it can harm them, or do they actually have a biological makeup which renders the neurotoxin ineffective? Are all animals who are broadly venomous to other species immune to their own toxins? 82.92.119.1109:29, 6 May 2006 (UTC)[reply]
To answer your latter question, no. Your own example of the scorpions is a good example of that. On nature channels they often show two scorpions fighting, resulting in the death of one. Their protection against the venom is their exoskeleton. - Dammit09:37, 6 May 2006 (UTC)[reply]
Our own scorpion article states "the belief that scorpions commit suicide by stinging themselves to death when surrounded by fire is of considerable antiquity and is often prevalent where these animals exist. It is nevertheless untrue, since the venom has no effect on the scorpion itself, nor on any member of the same species (unless the venom is injected directly into the scorpion's nerve ganglion)." This doesn't seem to imply the exoskeleton is what renders the venom ineffective, since otherwise the "same species" mention is peculiar. The article doesn't seem to be saying that the venom is ineffective because the stingers can't penetrate the exoskeleton (although it does say that if the toxin where to reach the ganglion directly somehow, it would be effective). Is the artticle wrong or simply misleading? 82.92.119.1109:58, 6 May 2006 (UTC)[reply]
Hmm, I'm probably wrong then. It could be that the fights I saw on tv where different species (I recalled it from memory, havent actually seen one recently). - Dammit11:23, 6 May 2006 (UTC)[reply]
I guess that it is quite common for poisonous animals to have better resitance against their own poison since that sounds to me like a quite obvious useful trait. ALso regular contact to the poison produced by the own body should produce antibodies. But that doesn't mean that all species are totally immune or even have better protection against the poison than animals in general. These are just my own guesses based on general knowledge about animals. Jeltztalk16:22, 6 May 2006 (UTC)[reply]
Interesting. Apparently the cobra (and the mongoose) has its acetyl choline receptors at the neuromuscular junction "shielded" from the effect of the neurotoxin, by a genetically determined sugar complex overlying the binding sites. The normal ACh can "get through the holes" in this shield and still cause normal muscle contraction. The resistance that the elapids have to their own venom is thus not a function of their immune system as such. In contrast, the viperidae have circulating antibodies which neutralise their proteolytic venom, and their tissues lose their resistance in the absence of their serum. The pufferfish's immunity is based on the substitution of a single amino acid in the sodium channel protein. Japanese sushi chefs are trained and licensed to try to reduce the incidence of TTX poisoning, and they are required to eat the pufferfish dish that they have prepared as part of the exam. --Seejyb20:53, 6 May 2006 (UTC)[reply]
So it appears that all mechanisms occur in practice: "active" immunity through antibodies and "passive" immunity by a change in regular makeup which renders the toxin ineffective. I'd also half expect some species to have no immunity to their own poison, but it would take an unusual set of circumstances for this not to be a huge drawback (as other members of your species would likely compete with you over territory/food/mates and casualties would be very high). 82.92.119.1121:52, 6 May 2006 (UTC)[reply]
Actually some poisonous species fight among each other, and are vulnerable to each other's poisons. The difference is that the gland producing the venom is usually carefully contained within a thick layer of lipids so as not to have it escape to the bloodstream. However, when used against another organism, usually it is injected through fangs, which pierce skin, and any lipids, or similar protection on another species. If you were to pierce the venal glands of another species, that species may die. Of course, additional protections and immunities may protect that. Elle vécut heureuseà jamais (Be eudaimonic!) 23:55, 6 May 2006 (UTC)[reply]
The Perfect Crime
Supposing you had to off a someone who happened to be an insulin-dependant diabetic, preferably without getting caught. What if you were able to remove the insulin from one bottle and replace it with a glucose solution, put the spare bottle in the microwave and then replaced them both where you found them. How long would it take for the glucose to have its effect, and would it be fully lethal? Obviously you'd need to dispose of the glucose-containing bottle, wash out the syringe, maybe take up some denatured insulin into the syringe and perhaps wipe the point of injection with some damp cottonwool to remove and traces of glucose. What would be left for forensics? They'd check his blood sugar and it'd be through the roof... would this look suspicious? How about if the glucose solution also contained some alcohol... would they check stomach contents? --Username132 (talk) 11:14, 6 May 2006 (UTC)[reply]
I think it is important to point out there is little or no forensic evidence in most cases (even murders). Life is not like CSI. --66.168.20.714:08, 6 May 2006 (UTC)[reply]
You were asking how long it would take for the glucose to take effect. Leaving aside the rather gruesome and distasteful nature of your post, if you do a first aid course you get to learn that hypoglycemia (caused by too much insulin and/or not enough food for the amount of physical exercise) can have a very rapid onset, but that hyperglycemia, although potentially just as serious, is a condition with slow onset over many days. Arbitrary username15:59, 6 May 2006 (UTC)[reply]
I think a diabetic would probably notice very quickly if their insulin wasn't having an effect. And I don't think hyperglycemia would kill someone before they could get help. Besides, everyone knows the best way is to whack someone on the head with a frozen loaf of bread, thaw it, and feed it to your dog. --BluePlatypus19:52, 6 May 2006 (UTC)[reply]
Your idea doesnt come close to working for a variety of reasons. Removing the insulin and filling the bottle with glucose would be equivalent to delaying or skipping an insulin shot and then taking a sip of regular soda. Hardly a recipe for sudden death-- people with diabetes do this all the time. alteripse22:10, 6 May 2006 (UTC)[reply]
And apart from what Alteripse mentioned, getting the syringe and insulin would almost certainly involve leaving trace evidence of some kind even if you were careful to get rid of foot- and fingerprints. If you've been on a crimescene, you always leave something behind. - Mgm|(talk)14:16, 7 May 2006 (UTC)[reply]
Effect of wrong phasing (3-phase supply) connection to the UPS
I would like to know the effect of connecting the wrong phasing power supply to the UPS in the telecommunication base station.
Explaination with diagram would be very helpful.
Thank you
Perhaps you could improve your question; I don't understand your question and it doesn't seem as if anyone else has either. What is "the wrong phasing power supply" and which "telecommunications base station" are you referring to? Andrewjuren(talk)07:09, 7 May 2006 (UTC)[reply]
I think his question was about wrong phase sequence. That is, what happens if one connects RBY to terminals marked RYB (R-R,B-Y,Y-B instead of R-R,B-B,Y-Y) of an UPS (doesn't matter were the UPS is used) -- Wikicheng08:42, 8 May 2006 (UTC)[reply]
Yes, Wikicheng is correct-what is the effect if the supply connected to the UPS is in the wrong phase sequence RBY instead of RYB.
Pearson Correlation
Would it be correct to say (as a general conclusion for relationships among correlations/ Pearson correlation) that if X is related to Y and Y is related do Z, that this necessarily means that X is related to Z? -- 4.155.249.9317:04, 6 May 2006 (UTC)[reply]
No, correlation is not transitive. Consider f(x) = Sin(x), g(x) = Cos(x), and h(x) = Sin(x)+Cos(x). h(x) is partially correlated to both f and g, but f and g are uncorrelated to each other. Dragons flight17:59, 6 May 2006 (UTC)[reply]
And you can easily extend this to a situation where f and g are actually partially anticorrelated, while h is still partially correlated to both f and g. Just consider f(x) = Sin(x), g(x) = Sin(x+2pi/3), h(x) = Sin(x+pi/3). Arbitrary username18:04, 6 May 2006 (UTC)[reply]
modern communications technology
I would be interested in a recap or summary of the latest communications technology that includes such devices as the internet, telephone linkages, digital photography etc., and what these actually do in the real world. Thank you
Obviously, we all know that solutions to Schrodinger's equation is called wave functions. In convention, we call "a one-electron wave-function" a orbital. NOW, if orbital is essentially a mathematical description of the behavior of one electron, then why on every orbital we can have 2 electron filled up?
Thanks
Strictly speaking, you have to solve Schrodinger's equation for the system you have (e.g. an atom with multiple electrons). However, to an approximation you can use the solution of Schrodinger's equation for one electron (hydrogen atom) when considering the forms of the atomic orbitals in more complex atoms, provided that you take into account certain rules about how electrons behave. A key consideration is that electrons are so-called fermions, which means they obey the exclusion principle, that is the property that no two electrons can share the same set of quantum numbers. Each atomic orbital is described by a set of quantum numbers, but electrons have an additional quantum number, so-called spin quantum number, which for an electron can take two possible values (1/2 or -1/2). This means that a maximum of two electrons can share the same atomic orbital without violating the exclusion principle. Arbitrary username17:53, 6 May 2006 (UTC)[reply]
You don't have to make the approximation of using hydrogen orbitals. - You still can describe the total wave-function in terms of single-electron orbitals. They're just different from the hydrogen ones (and can't be solved analytically). However: When you solve the Schrödinger equation for a two-or-more-electron system, you can't just solve the thing, because of the aformentioned exclusion principle. What this means is that the wave equation must also be antisymmetric with respect to the exchange of two electrons. Not just any solution is valid, in other words. Once you satisfy that condition, (for instance using a Slater determinant) then you can have two electrons with opposite spin in the same spatial orbital. Note that your resulting wavefunction is no longer a simple product of one-electron orbitals, but a rather large linear combination of them. But they're still one-electron orbitals. --BluePlatypus19:29, 6 May 2006 (UTC)[reply]
Somebody must know. Surely people who've come out of comas have been asked what they experienced, and whether or not they dreamed. JackofOz02:25, 7 May 2006 (UTC)[reply]
If they say yes we have the answer, but if they say no we don't, because even during normal sleep people don't always remember their dreams. --Ginkgo10003:01, 7 May 2006 (UTC)[reply]
That's fine. But all it takes is one ex-coma person to remember they were dreaming at some stage, and that proves it can happen. And surely coma patients have been monitored to detect evidence of REM. Is MacDavis saying no REM activity has ever been detected in a coma patient? JackofOz03:12, 7 May 2006 (UTC)[reply]
I don't think that's true. What if the person has dreamt in a normal sleep just after he's come out of the coma? How would ey know? – b_jonas13:00, 7 May 2006 (UTC)[reply]
I think the real question is whether people in comas experience REM sleep, since it is during REM that we dream. Unfortunately, I don't know the answer to that question. --Ginkgo10015:54, 8 May 2006 (UTC)[reply]
Helicopter and Car
A 5500kg helicopter accelerates upward at 0.50m/s² while lifting a 1200kg car. What is the lift force exerted by the air on the rotors? What is the tension in the cable that connects the car to the helicopter?
I drew my free body diagram and this is what I got for the two equations:
Helicopter
ΣFy = ma
FA - FG1 - T2 = m1a
Car
ΣFy = ma
T1 - FG2 = m2a
FG1 being 9.81 x 5500, T2 being 0.5x 1200, T1 being 0.5 x 5500, FG2 being 0.5 x 1200
My problems lies here. I need something to cancel out so I can solve for FA or T, but nothing cancels out. T1 and FA are the same the force, and so are FG2 and T2, and I've tried going FA - FG (total) = m1a and FA - FG2 = m2a but I that didn't give me the right answer either. I think my problem may lie in the fact that I have acceleration as FA. I've noticed that in some questions that we have done that acceleration is sometimes FA, and sometimes isn't included at all on that side of the equation. Anyone know why? Now as I think about it I don't even know why I have a T1 and T2 and not just T... I am really unsure here. Thanks. C-c-c-c19:34, 6 May 2006 (UTC)[reply]
Maybe I should just clarify what I mean by appealing to Newton's third law here. I mean that the two tensions will also act on the cable. If we assume the cable is very light, then if there was any significant difference between T1 and T2 it would lead to a huge acceleration of the cable. Hence we can treat it that T1=T2. Arbitrary username21:21, 6 May 2006 (UTC)[reply]
Okay, problem seems to be firstly that you've got these two different tensions, and then made some unfounded assumptions about what they should be equal to. Just set them both to T, and then solve for FA by adding the two equations:
FA - FG1 - FG2 = m1a + m2a
or as I'd prefer to write it,
FA = (m1 + m2)(a + g)
That gives you FA, which (no surprises) is enough to counteract gravity and provide the upward acceleration, for the combination of helicopter plus car.
Also you have
T = m2 (a + g)
In fact it's an important result that an upward acceleration and a gravitational field have an equivalent effect, so the a+g in the answers is no surprise.
Thank you so much! I just have one more question related to this, you said that all you have to do is add the two equations and I was always told I should subtract them. Your method does give the right answer, so does it work either way? Also when you're subtracting, wouldn't it matter which order you put in your equations (eg. 2 - 5 = -3, 5-2 = 3). This gives you the same number, but negative, so could it just be giving it in the opposite direction? Thanks a lot again. C-c-c-c20:53, 6 May 2006 (UTC)[reply]
Think about what you're doing when you "add" or "subtract" equations. You can do anything to the left side of an equation that is numerically equivalent to what you do to the right side. For example, adding terms to each side which are known to be equal because of another equation that you have. Or subtracting them. Which you actually do will depend on what terms you are trying to eliminate. Arbitrary username21:21, 6 May 2006 (UTC)[reply]
Oh, I see now. I thought it was one either one or other, and there wasn't choice between adding or subtracting. Thanks a bunch. C-c-c-c21:31, 6 May 2006 (UTC)[reply]
Identification of stars as distant suns
My question: when did we start "knowing" that the stars in the night skys are actually very distant stars? The star article itself is severely lacking in the cultural and historical prospect... Anyway after a bit of searching now I know there was this Nicholas of Cusa who proposed that stars are suns, though obviously he would not be able to "prove" his claim. However nowadays everyone regards this idea as a fact. So when and how people "prove" that stars are in fact suns very far away but not lamps embedded on the celestial sphere? Thanks! --Lorenzarius19:48, 6 May 2006 (UTC)[reply]
The idea of extrasolar planets is more modern, but I believe Archimedes was able to prove that stars were distant objects, or even earlier, I think. It would be plausible for the Babylonians or the Egyptians to have known it. (Let me check a few articles). Simple trigonometry was used based on measuring the changes in distance over different positions. Naturally an extremely large distance would mean miniscule changes in perspective. Elle vécut heureuseà jamais (Be eudaimonic!) 22:32, 6 May 2006 (UTC)[reply]
Yup, with the method of parallex we would be able to notice minute movement against the stellar background of some very close stars. Ancient people would also know that the stars are more distant than the Moon, Jupiter, Saturn etc because they could observe the eclipse of stars by those solar system objects.
But perhaps let me rephrase my question: how did we know that the Sun is just one of the stars, and that the distant stars are the same thing as the Sun? --Lorenzarius23:13, 6 May 2006 (UTC)[reply]
Actually the idea is fairly modern, with the invention of mass spectrometry did we "prove" that our sun was like other stars (or vice versa) - full of hydrogen, though differing in mass. The hypothesis was probably earlier, but it is my guess it wouldn't be more than 100-200 years before the mass spectrometer's invention, because the article at astronomy says that the idea that the sun was like other stars was fairly recent. Elle vécut heureuseà jamais (Be eudaimonic!) 23:15, 6 May 2006 (UTC)[reply]
Ordinary spectroscopy in the visual spectrum, not mass spectroscopy. Mass spectroscopy would require a sample. Which I think it's safe to say we don't have. --BluePlatypus00:49, 7 May 2006 (UTC)[reply]
The article "Breath" says that we inhale and exhale the same amounts of Nitrogen, about 78%. Obviously, at least to me, we're not absorbing it. Does this demand a natural defense mechanism, or is it rather the lack of anything for the nitrogen to bond to? (Mixed answers are thus fairly acceptable) THANKS! This is such an amazing resource, and that's just the articles on their own.
It is simply diffusion, or osmosis (sort of). There are little processes that consume nitrogen, so the nitrogen content in the bloodstream and the nitrogen breathed in is the same. There is exchange, but they are the same type of molecules, so the net diffusion rate is zero, though nitrogen molecules diffuse through the membrane of the air sacs at all times. Oxygen diffuses in because the oxygen content in breath is higher than that of the bloodstream (and is further attracted to haemoglobin), and carbon dioxide diffuses out because carbon dioxide content in the bloodstream is greater than that in the lungs. Nitrogen does get absorbed if the nitrogen content in the air is greater than that in the bloodstream...when you do deep water diving one risks getting decompression sickness too easily because the nitrogen has been pressurised and sudden retrieval upwards causes it to burst...then there's the opposite with nitrogen narcosis. Elle vécut heureuseà jamais (Be eudaimonic!) 23:51, 6 May 2006 (UTC)[reply]
Well, if there was something for it to bind to, we'd absorb it. I'm pretty sure that the body does not have anything which specifically binds nitrogen gas molecules as with O2 and hemoglobin. We don't have any use for it. Although there are bacteria which use nitrogen gas. (nitrification bacteria) As pointed out above, nitrogen gas (like all gasses, to different extents) does dissolve in water. Since the nitrogen dissolved in your body is in equillibrium with the nitrogen in air, you get the same amount going in and out. What happens in decompression sickness is that that equillibrium is disturbed, since more gas (again, like all) will dissolve into in your body at higher pressure. So if you suddenly drop the pressure, the nitrogen will evaporate into bubbles, which is very dangerous. It's the exact same thing that happens when you open a can of soda. Once the soda has gone flat, it's reached equillibrium with room pressure. So it's not about the concentration. Just the pressure. --BluePlatypus01:00, 7 May 2006 (UTC)[reply]
The dinitrogen molecule is extermely inert in the absence of a catalyst. Only a few bacteria have evolved the ability to reduce nitrogen from the air to ammonia and use is in their metabolism. Wikipedia has an article on nitrogen fixation, unfortunately it's not very good at the moment.
Nitrogen goes into the lungs, is dissolved into the blood stream, body fluids and cells in proportion to it's partial pressure, However, even though the nitrogen molecules are floating about in all these fluids (everywhere - eye to big toe - at the same partial pressure) the body does not do anything with it, i.e. does not utilise it in any chemical reaction, nor does the body produce any N2 by any chemical process, nor does the N2 molecule take part in any unwanted chemical reactions (no defences needed). Therefore, at a constant pressure, the nitrogen that you breathe out is the same as what you breathe in - no nitrogen added or taken away or changed. Your conclusion, though mainly correct, is based on figures for dry gas. In reality the air you breathe out contains approximately 6% (approx 6 kPa) water vapour (at sea level and body temperature), so that the percentages given in the article are not true for the air coming out of your mouth or nose. I shall see if I can adapt the article, while still pointing out what you deduced. --Seejyb23:32, 7 May 2006 (UTC)[reply]
May 7
Difference in Time
What is the difference in time during the existance of the universe as we know it today and since the Big Bang and anytime prior to the Big Bang? -- PCE 00:22, 7 May 2006 (UTC)
There are many a misconceptions about the big bang caused by popularization. The big bang was not the so called, beginning of the universe/time. It was only a time period in which spacetime started to expand— for unknown reasons. Everything was still there before the big bang, the big bang was not a moment of creation either.-- Mac Davis] ⌇☢ ญƛ.
The Big Bang model goes to 10e-43 seconds. As far as most people are concerned, that's close enough to the beginning of the universe. I am fully aware that the stuff that happens before is "important", but to my knowledge there is no model which has general scientific consensus. So, I guess to correctly answer PCE's question: 13 billion years since the Big Bang and there were 10e-43 seconds before the Big bang. Andrewjuren(talk)07:03, 7 May 2006 (UTC)[reply]
Sorry, I didn't mean to "condemn" your answer or anything, it was just fine, and you are right. But I do not agree with you impling that the big bang was the beginning of time and/or the universe. -- User:Mac_Davis (unlogged in) 11:40, 7 May 2006 (UTC)[reply]
Do you have a citation for that? The Stephen Hawking article seems to indicate that Hawking believes there was no "time before the big bang": "Asked in October 2005 to explain his assertion on the British daytime chat show Richard and Judy that the question, 'What came before the big bang?' was meaningless, he compared it to asking, 'What lies north of the north pole?'" Chuck19:26, 8 May 2006 (UTC)[reply]
Also keep in mind that cosmologists and astrophysicists are still not 100% certain abut the origins of the universe. This, for example, gives a different interpretation to the events around the Big Bang. Grutness...wha?07:45, 8 May 2006 (UTC)[reply]
Celestial Names
When a new celestial object is discovered, it is immediately given a specific name (at least in English...its name in other languages may be different). I understand that our planets have been named after Roman gods, but this goes back to antiquity. I also understand that certain planets' moons are named according to a theme, for example (forgive me for forgetting which one) one planet's moons are named after Shakespearian characters. But that is also an old tradition. (Also, it seems pretty anglo-centric...are those moons named differently in different languages? For example in Russian are they named after characters created by Russian authors?).
What I'm really getting at though is, say a comet is discovered, or a new extra-solar planet. What organization or body is it that seems to have the authority to define these objects' names? Loomis5102:04, 7 May 2006 (UTC)[reply]
Pink? Is there a new bill that I haven't seen yet? I know that the bills have blue and red threads in the paper that is used. These threads are in the paper so that you can tell that someone didn't just print a scan of the bill on normal paper. There is more info about Counterfeiting and Security printing. Dismas|(talk)03:59, 7 May 2006 (UTC)[reply]
See [19]. I think it's not so much that it's pink, but rather that there are multiple colors, and a gradient of color on the reverse. Ardric4704:01, 7 May 2006 (UTC)[reply]
I lost my answer in an edit conflict, sorry. I did say however, that when giving money for ransom, the police often put a dye bomb in the cash-bags, that explodes and magenta dye covers nearly all the bills. --Usre:Mac_Davis (unlogged in) 11:35, 7 May 2006 (UTC)
well, why not pink? who says green is the definitive colour for money? surely you don't think that people might think your gay if you pay with pink money, do you? that would just be tragic!
(this comment was added by someone who doesn't know how to sign their own name)
Who says? I fucking say! I don't care about the sexual orientation of my money, I just don't want it to be salmon pink! Green and black. Nothing shiny, nothing pastel, just green and black. That's all I ask. And I still don't know, how in God's name is the color supposed to protect us? Complexity I understand, watermarks I understand, UV sensitivity I understand, but why PINK?Black Carrot03:08, 8 May 2006 (UTC)[reply]
If you don't care about the sexual orientation of your money, why did you introduce that very concept in the title the question "Queer Printing"? Seems you're not as entirely indifferent to it as you claim. JackofOz03:25, 8 May 2006 (UTC)[reply]
Does anybody know the technical term for the "red-eye" effect in photography? I thought that it began with "hemo-", but I might be totally wrong. Please, please, please, if anybody knows, I'd greatly appreciate it. (I doubt that I'll be able to sleep until I find out!)
"Hemo-" means blood, so we are on the right track. However, the OED has no technical term for this effect. Interestingly, Googling for hemo and "red eye effect" suggests the word was in the Wikipedia article in an earlier edit, but I haven't been able to find it. Hope you got some sleep! --Shantavira07:58, 7 May 2006 (UTC)[reply]
Intelligent Design
Many evolutionary scientists have criticized and refuted the arguments given for Intelligent Design.Well, how have Michael Behe,William Bemski, and other advocates of Intelligent Design reponded to these criticisms?
Also, if you look at refractometer you should probably find some stuff on the refractive index of different concentrations of sucrose solution, as that is the standard against which other concentrations are determined with these machines. Skittle16:14, 7 May 2006 (UTC)[reply]
Sugar dissolved in water will also change the refractive index of the solution. And it will vary with concentration, so you can use that as a way to determine the sugar concentration with a refractometer (typically an Abbe refractometer to be precise). It's a good-old fashioned kind of chemical analysis instrument you don't see that often nowadays. --BluePlatypus18:15, 7 May 2006 (UTC)[reply]
(Addendum: Apparently I'm not only old, but a bit blind too, since I somehow missed that Skittle had given essentially the same answer). --BluePlatypus18:19, 7 May 2006 (UTC)[reply]
Hey, it's probably the chemical analysis intrument I see the most of. And Blue Platypus's answer was better. Brix scale if it helps Melchoir. Skittle13:46, 8 May 2006 (UTC) (Hmm, seems to be red. Brix has some info, but not as practical as it could be)[reply]
Light
Is there an existing material that can travel faster than light?Does wikipedia have an article on it?i would love to check it out
It's probably not true that being a tachyon means traveling back in time (or FTL travel). Rather, it just means an odd dispersion relation until the stable vacuum is reached. -lethetalk+09:45, 7 May 2006 (UTC)[reply]
Isn't there some law of physics relating to e=mc2 that says it is impossible to overtake light if you are slower than it, and go slower than it if you are faster than it. And also that objects that are faster than light cannot interact with objects slower than light? I' not actually sure, and I don't know where to look to verify this, so if anyone else who knows about this could so, it would probably help. But more to the point, if I am correct, there may be things going faster than light, but it is impossible for us to know. PhilcT+C09:30, 7 May 2006 (UTC)[reply]
Ah, yes, I found it at tachyon, if a Tachyon does exist, and travels faster than light, if we were able to interact with it it would violate causality, as loops in time could be created leading to plentiful paradoxes, therefore if they do exist, there is no way for us to know. PhilcT+C18:04, 7 May 2006 (UTC)[reply]
Anyway, the short answer is that it isn't possible because physicists have once decided that it wasn't, and since that time they keep redefining FTL so that it would exclude any possible way of travelling faster than light so as to guard their self-pride. – b_jonas12:55, 7 May 2006 (UTC)[reply]
Well, to be fair, the examples given in that article do seem pretty useless. Unless you can pilot a spaceship or send messages across the galaxy, what good is it? Black Carrot02:59, 8 May 2006 (UTC)[reply]
detecting UV rays
i know that human eyes cannot detect UV rays.but is it possible to have any sorta eye surgery so that our eyes can spot UV rays without any damages?
We can get Infra-red goggles, so If you are determined to see UV, im sure its possible to make some goggles that pick them up or something. PhilcT+C09:32, 7 May 2006 (UTC)[reply]
Infra-red is actually the opposite of UV, so i doubt that typical Night vision goggles would be much help. The trick to seeing UV rays is actually not hard, since they are energetic. Simply get a filter that only allows for UV rays to pass through, and then hit a material that will fluoresce properly, to convert the UV rays to normal light, and just watch them! This is how you 'see' things in a room lit up by only an ultraviolet bulb, visible light is supressed and only objects that fluoresce the light back to the visible range show up, like white socks, teeth, psychadelic posters, etc.
There exists a device known as a starlight scope. I believe it uses ultraviolet from the stars at night to see.
Scientists investigating crashed spaceship
I'm writing a story that involves a crashed spaceship, among other things, and originally I just had SAS soldiers securing the site (plot device to get my characters there). It occurs to me that the government would also send scientists to investigate it. After all, that's what they do in movies and so on.
But exactly what kind of scientists would be sent? I can't imagine we have too many people lying around with a degree in extraterrestrial technology study.
Astrophyscists, engineers, nanotechnologists, & geologists (for examining the spaceship) biologists, bio- and astro- chemists, read Deception Point for more. For specific people, maybe you could add Michio Kaku and... that's all I got. Assuming its in the future. Don't forget Delta force, in case anything funny happens with the aliens. -- Mac Davis] ⌇☢ ญƛ.10:33, 7 May 2006 (UTC)[reply]
Well, if SAS soldiers are being sent in, I'd presume that the crash doesnt take place in the United States, so I can't see a US-government task force being the first on the scene. GeeJo(t)⁄(c) • 11:47, 7 May 2006 (UTC)[reply]
Thanks. It does in fact take place in Australia, in the Snowy Mountains to be specific. I'm especially pleased you mentioned a nanotechnologist; nanotechnology plays a part later on in the story, and putting one in beforehand means I can set up an udnerstanding of it before the reader actually has to cope with it as part of the plot.
Alot of stories send mathemiticians on trips to communicate with other life-forms, as it is the only common language we will have. PhilcT+C15:24, 7 May 2006 (UTC)[reply]
Maths is always the same, no matter where you go in the universe 2+2=4 F=ma and e=mc² so thats how its vaguely similar. addmitadly it cannot be used to communicate much, but it allows both species to gauge the others intelligence. However little you can get across, its better than just sitting there squeeling at each other in your respective languages at your respective frequencies. PhilcTECI21:45, 7 May 2006 (UTC)[reply]
Alright, let's assume we structure our quantitative views of the world more or less the same. Let's just say. How, then, are we supposed to communicate our understanding to the aliens without language? Cut up some squares and demonstrate the Pythagorean theorem? Black Carrot02:42, 8 May 2006 (UTC)[reply]
The prime numbers are generally the best idea for a start. Then do the periodic table to demonstrate scientific understanding. --212.241.231.5203:19, 8 May 2006 (UTC)[reply]
Even if you can only cut up squares and show each other pictures, all you have to do is show them a number square, and it would take seconds to grasp the ten based decimal system. There are only four basic functions, plus minus multiply and divide, so once weve got them acroos, you can discuss mathematics. However pointless it is there is no other way of communicating anything! ok! its better than nothing!!! PhilcTECI11:12, 8 May 2006 (UTC)[reply]
I hope the aliens aren't made of antimatter. That would be bad, eh?
IN THE NAME OF HOOLA, there's edit conflict for a reason! Don't just delete my article like that! *hrm*... now. Humans see roughly from 400nm to 700nm waves (IIRC). First of all I would like to ask: If we could see from, say 300nm to 800nm, would we perceive the colours as the same, but "spread out", ie seen only a stretch? Then there is another, bit tougher question: Some animals are bound to have different spectra, what are the lowest and highest wavelengths that some animals can perceive in vision, that we know of? Manymanymanymany thankseses. :)
Sorry, it was me. Accident. The colors would not be the same at all! We would see completely new colors. Colors that we literally can't imagine. The lowest and highest are of the animal kingdom seen ultraviolet and infrared, although I am not sure of the wavelengths. --User:Mac_Davis (unlogged in) 11:31, 7 May 2006 (UTC)[reply]
Oh, thanks. Definitely not my intention to come off as cross, I should have placed a smilie in. ;) Thanks - it's the wavelengths that I'm interested in.
Okay, this'll probably get me banned from the reference desk. Let's pretend there's this traffic light at an intersection that never works properly, and despite the amount of protests and complaints to the state transportation (and whomever deals with transportation in the county, as well), nobody has come out to fix it. Let's also pretend that I'm fed up with said traffic light and wish to perform malicious action on said traffic light to force the DOT to come fix the damn thing. My question is, what would send a clear message and not allow me to be caught (hypothetically): a localized electromagnetic pulse (and how would one construct a device to do that)? A small explosive? It would, of course, be mounted on the control box. CernenXanthineKatrena13:25, 7 May 2006 (UTC)[reply]
No hope, those things can take hurricanes. With our local paper, they have a daily article on the 'fixer', in which people complain about potholes and such. They are usually fixed the next day. --Zeizmic13:38, 7 May 2006 (UTC)[reply]
Low-yield EMP bomb? :D
You could get one of those devices that ambulances and fire trucks use to change the lights for them while they are approaching it. Although, it's illegal for private citizens to own one... but you know... Dismas|(talk)15:41, 7 May 2006 (UTC)[reply]
While traffic lights might not be susceptible to hurricanes, they do not survive lorry fires adjacent/right beneath them (there was one such incident in Wells a few years back). Alternately thermite might do the trick... Thryduulf15:48, 7 May 2006 (UTC)[reply]
Well, it depends. If it doesn't have cameras attached (a lot of the ones around my house do, to catch people speeding), it gets alot easier. Wait for a time of day (or night) when there's nobody around, climb up on it, and smash one of the lights with a hammer. Or, cover it with paper; it'll still be disabled. As far as getting banned, people have asked about the mechanics of suicide in a padded room. Questions aren't a problem, as long as they're actual questions and not reformatted speeches. Black Carrot21:10, 7 May 2006 (UTC)[reply]
If you are trying to create an emp grenade you have several options a capacitor bank (one about the size of a small house would do the trick), a specially construced tool which uses a spinning disk going very fast to cut through the field lines of magnets, so when the circuit is completed for a split second you will have mabye a Megamp of current (sorry can't find its name anywhere), or you can use a current going through a coil (an electromagnet) and use small explosives to collapse the coil very quickly, this will cause an incredible rise in current, and since its already a coil, voila emp. But all of this is pretty unpheasable for the task of dealing with trafficlights, mabye you should just tie them to your car and yank them over, or even easier, as someone suggested earlier i think, set off a large nuclear weapon in the upper atmosphere. ;-) PhilcTECI22:00, 7 May 2006 (UTC)[reply]
Well. I don't think I could detonate a nuclear warhead (my insurance doesn't cover fallout from even accidental detonation of a nuclear device -- what a load of crap, hm?). And so much for the emp grenade. I could hit it with a sledgehammer, but there's a 7-11 right in front of it (which means that I can be caught...). It's not the lights I want to damage, it's the control box. They'll have to send a technician instead of just a repair crew, it'll be costly, and painful, for the county to do that. I was thinking of hitting it with the sh*tmobile...do you think a vehicle accident would take one of those puppies out? After reviewing a wikibook on thermite synthesis, I think I may have my answer, but the question is, is such a reaction simply incendiary or explosive? CernenXanthineKatrena10:15, 8 May 2006 (UTC)[reply]
Yeah, it bloody pisses me off to when your neighbours accidentally set off their nuclear warhead, and then you have to ask them to cover the damages, because your insurance doesn't cover it! PhilcTECI22:32, 8 May 2006 (UTC)[reply]
carbon in body
carbon isnt necessary for human survival,yes.But is it that carbon is needed atleast in little content in our bodies?or maybe i am wrong?If not,what are the diseases caused by deficiency of carbon?
--thanks!
I imagine starvation. Just about everything we consume has carbon in it. I don't know how the uptake of carbon works, if there is any.
No, your body cannot do anything with pure carbon, however in cases of drug overdoses, paramedics often deposit activated carbon inside a patient's stomach to absorb the toxins --Crucible Guardian23:25, 7 May 2006 (UTC)[reply]
I don't know if they still recommend it now, but 30 years ago, my dad was given charcoal tablets to try to deal with his upset stomach; same principle, I assume. --jpgordon∇∆∇∆23:43, 7 May 2006 (UTC)[reply]
I have recently received a computer [for free] from my father’s company. He didn’t want it, so now it’s mine :P. I have a weird problem though: every time I turn it on, the computer asks me to log in with a username and password. FWIW, the computer runs on Windows 2000 Professional. I’ve tried to get around the login by going into safemode and whatnot, but it always ends up on the login screen. Even if I type in a legitimate username and password, I can’t get through, because the computer is making a vain attempt to connect to a server that no longer exists. My question is this: is there a way for me to disable the network login without being able to bypass the login or having boot disc for Windows 2000? Perhaps there is a way to get into DOS upon startup and disable networking…?--Theikiroid (talk)(Help Me Improve)16:44, 7 May 2006 (UTC)[reply]
If you don't like Trovatore's suggestion (I may be a penguin fan, but it's not always the right solution) there should be seperate "Safe mode" and "Safe mode with networking" options. Also, at the login screen you should be able to select between logging in locally and using a network (domain) login - if you don't get a third box to select that beneth the username ansd password boxes then click "Options" and it should show up. Another possibility is that the recovery console may be installed - if it is then it will be shown as an option on the boot menu, you will need the local admin password to use it. -- AJR | Talk23:04, 7 May 2006 (UTC)[reply]
With old corporate, networked PC's and laptops, the only answer is to go to Linux. First, for a corporation to give it away, it has to be really old! Second, the corporate IT-jocks have probably really done a number on it, for 'security'. I've had lots of success with those throw-aways and Linux. --Zeizmic23:45, 7 May 2006 (UTC)[reply]
You'll get nowhere without admin priviledges, that is the way the system is designed, and it is quite good at it. If you cannot get these passwords (company may not want to reveal these), you can ask your dad to get the company IT person to add an admin account for you (he would have to take it in for this). Then all the logins and startups can be accessed and changed, using the new admin account. The simplest is really installing a system that you own - sounds like you are most comfortable with Windows, but that costs, whereas Linux is free, and the newer GUIs are relatively easy. If the system is running Windows 2000 it can't be too old. --Seejyb11:20, 8 May 2006 (UTC)[reply]
I dont know, its strange, consumers do something with them, the name suggest consumers consume, but to me atleast it implies ingestion... PhilcTECI22:02, 7 May 2006 (UTC)[reply]
History of Health Screening
My stepdaughter has been trying to find information on the history of Health Screening (as we are in the UK, I suppose with a UK bias) and has had little success. I too have tried and not really found anything. Could someone please point us in the right direction or give us some information. Many thanks. emjay----------
Fullerene
I had heard about fullerene, and learned a few thing about it, but never seen it until I saw the wiki article on it, where it shows the compound in crystalline form. I thought, how is fullerene bonded as a solid, was this at extremely low temperature, or is there a bond between the balls, or what, are they held together by Van der Waals, if that is possible. If they are, how can they stay together at high temperatures. Also the same question about buckminster fullerene, as that has Carcons with only 3 bonds, which would make inter molecular bonds possible (wouldn't it) so is that bonded differently? PhilcT+C18:46, 7 May 2006 (UTC)[reply]
Indeed, they are held together by VdW forces, and are therefore weak and soft as a solid. They sublimate at high temperatures. The carbons have more than three bonds, though - it's a conjugated system, so while it's possible for them to bond to other molecules, but that would break the aromaticity of the system, so they're not very happy to do so. --BluePlatypus20:18, 7 May 2006 (UTC)[reply]
the gay gene
hi,
now that its estabished that people are gay through nature rather than nuture, does anyone know whether there was definitive study that drew this conclusion or was it more a set of smaller ones that tended towards it? if anyone could direct me to them then that would be great. also, i would appreciate it if bigots wouldnt post their vitriol here... thanks! andrew
There is almost certainly no single "gay gene". If homosexuality were a simple Mendelian trait, this would have been known for a long time. People with axes to grind on both sides like to describe homosexuality as though it were one single well-defined thing, but human beings are a bit more complicated than that. --Trovatore19:42, 7 May 2006 (UTC)[reply]
"now that its estabished that people are gay through nature rather than nuture" - So, every single experiment peformed everywhere in the world by every scientist has proven that people are gay through nature, not nuture? Wow. That's news. I'm surprised to find it in the Wikipedia Reference Desk and not on CNN. Or... is this just another troll using a false assumption to pose a baited question? --Kainaw(talk)22:39, 7 May 2006 (UTC)[reply]
Homosexuality is most definatly not caused ONLY by genetics. Several studies on identical twins have been done that show that genetics probably plays a roll, but if genetics were 100% responsible for homosexuality, the percentage of twins that had the same sexual orientation would be 100, but it is not even close. It's more like 40-something. --Crucible Guardian23:20, 7 May 2006 (UTC)[reply]
While I agree with you that it's certainly not 100%, 40% seems a little low. I haven't seen any recent statistics about sexual orientation (maybe someone could find some), but the most recent ones I remember seeing is that something like 10% of the population identify themselves as homosexual. (Note: I realize sexual orientation is much more complicated than a two-bin or even three-bin system, but I'm simplifying it for statistics sake.) Even if you up that to 20% of the population being homosexual or bisexual and 80% of the population being heterosexual, that would mean that if you pick two people at random, 64% of the time you would have two heterosexuals. So wouldn't 40% imply that twins are more different in their sexual orientation than two random people off the street? EWS23 | (Leave me a message!)23:49, 7 May 2006 (UTC)[reply]
petroleum distillates
Are petroleum distillates absorbed through the skin? I'm having trouble finding out information.
If they are absorbed, what is the effect on the body?
KeeganB
The problem is that "petroleum distillates" is a huge group of products. Some are absorbed and some aren't. For example, some petroleum disillates are skin lotions - if they weren't absobed, they'd be useless. Other petroleum disillates are like a wax (such as the waxy coating on milk cartons). It isn't absorbed by the skin because it is too hard of a wax - if it wasn't it too would be useless. Of the literally thousands of products made by petroleum distillation, you need to specify which ones you are concerned about. Obviously, the effect of absorbtion would be different depending on the product. Skin lotion makes your skin softer. There are some aromatics that make your skin smell better (or at least different than the normal skin smell). --Kainaw(talk)22:49, 7 May 2006 (UTC)[reply]
I'm talking about the kind in furniture polish. KeeganB
Oh, nevermind, I managed to find the MSDS. The answers is no. I'm such a fuck up. KeeganB
May 8
Boy with 'no brain'
This post claims that someone with only 1 cubic mm of brain tissue functioned normally, and a search for the professor mentioned in the post reveals similar stories. Do you know if this has ever been published anywhere reputable, or is it just a spontaneously generated bit of wishful thinking?
The article you mention was certainly published in Science Magazine (1980, 210, 1232-1234) which is a reputable journal, your interpretation of the facts in the post that you link to are not accurate. Here is a better description of the article which discusses the thickness of the cerebral cortex (a PORTION of the brain) and not the volume of the brain as a whole. Still, the article raises many questions. -- C. S. Joiner (talk) 00:42, 8 May 2006 (UTC)[reply]
I looked up the article (citation above). While Science is a highly reputable journal, it's in the "Research News" section, which means it's not a research paper, nor is it subject to peer review. Anyway, Lorber is quoted as saying "we saw that instead of the normal 4.5-centimeter thickness of brain tissue between the ventricles and the cortical surface, there was just a thin layer of mantle measuring just a millimiter or so.". Later in the article, a neurosurgeon points out out the difficulty of interpreting brain scans ("Interpreting brain scans can be very tricky. There can be a great deal more brain tissue in the cranium than is immediately apparent"), and is quoted as saying "Lorber may be being rather overdramatic when he says that someone has 'virtually no brain'." And Lorber acknowledges as much, but still says that the brain must nevertheless be substantially smaller than normal. So as pointed out, it's only a particular portion of the brain that's being referred to there (and then as "a few millimiters" as opposed to 4.5 cm). And that should probably be taken with a grain of salt. The overall impression of Lorber seems to be that he's fairly well-respected but considered something of the kind of provocateur who likes to make big claims and challenge preconceptions. (other controversial ideas of his are mentioned) In other words, worth listenting to, but not trusting blindly. In any case the "One cubic millimeter" claim is certainly false. But the gist of the thing - that there's someone out there with high IQ and a substantially smaller brain than most, is probably true. The main point of debate seems to be (or have been at that time) what role the cerebral ventricles play. --BluePlatypus01:08, 8 May 2006 (UTC)[reply]
And the cubic millimeter aspect refers to the thickness of a layer of cortex tissue, as I understand it, not a total volume of brain tissue. It is not a little cube of brain; it is a very squashed down and/or thin brain tissue. --Fastfission01:59, 8 May 2006 (UTC)[reply]
Good question. I'm not sure exactly. The announcement that the whole thing has been a great fraud? Or, if not (since reputable news sources are carrying it), a conclusion regarding the cause of it?JianLi02:52, 8 May 2006 (UTC)[reply]
What's bold about it? Note that I'm not saying everything gets absorbed faster as a hydrochloride. Nor did I say that it's the only reason hydrochlorides are used. If you expect a short, simple Reference Desk answer to a short, simple question to be an all-encompassing absolute truth of biochemistry, you're nuts. But no, I don't have any evidence of that. It's just what I was told in the (albeit introductory) class I took in pharmaceutical chemistry. Making something a hydrochloride salt can make it more water-soluble and faster to absorb in the digestive system. It seemed like a reasonable explanation to me then, and I assume that the people at the drug companies have the evidence to support it. I'm not exactly in the position to give a full review of all available litterature on pharmaceutical salts (and there seems to be a good amount of it), although I do feel pretty confident it doesn't contradict what I wrote. So what exactly do you think is wrong with that statement? --BluePlatypus04:46, 8 May 2006 (UTC)[reply]
Yeah, I just found that myself and was about to point it out. Hopefully it was written by someone with more direct experience than myself. At least it appears so from the details. --BluePlatypus05:03, 8 May 2006 (UTC)[reply]
In general, most organic compounds such as pharmaceutical drugs are more soluble in water when they are in a charged (ionic) state rather than a neutral one. A large number of drugs contain nitrogen atoms than can be readily converted to ionic ammonium salts by the addition of an acid. The ammonium salts tend to have better bioavailability than the neutral compound because of their better solubility. There are many pharmaceutically acceptable acids that can be used to form the salts, but hydrochloric acid is common because it is a strong acid that will completely form the ammonium salt. And there is plenty hydrochloric acid in your digestive system already, so it is unlikely to cause problems. --Ed (Edgar181) 11:57, 8 May 2006 (UTC)[reply]
plant question
does co2 in a plant travel through xylem, phloem, or...?
You may be thinking of stoma; CO2 that enters there doesn't have to travel very far to get to the places where it's needed for photosynthesis. --AySz88^-^03:37, 8 May 2006 (UTC)[reply]
ok. the longer explanation follows. im taking the bio ap tomorrow, and my teacher gave us a take-home open-note (and internet, but not fellow student) test on the last section we'd need to know for the ap. one of the questions was:
"If radioactive CO2 is supplied to a mature leaf of a plant, it is often possible to detect radioactivity in the young growing leaves of the shoot apex a few hours later. In which tissue did the radioactive compound(s) travel?
a. phloem
b. xylem
c. stomata
d. cortex
e. pith"
I'm damn near positive it's not cortex or pith because that wouldn't make any sense and pith doesnt even really fit in the whole picture. i know the stomata accept the CO2 and transpire away water, so i was thinking the xylem would carry it, because it doesn't seem to me that the stomata, being small, single cells, could be the "tissue" (if they're considered tissue, which I think they're not)in which the compounds "travel."
sorry i didn't elaborate earlier, and thanks for the help
The C02 moves int through the stomata where it immediately enters a palisade cell, energey is used from a light source to combine the CO2 with H2O to make C6H12O6 (glycerol) this is then transported around the plant via the Phloem cells, the xylem cells are solely for carrying this up from the root, the phloem move in any direction. so CO2 travels through stomata only, the C (which would be the radioactive part of CO2 most likely) would then travels about the plant in sugars, which are in the Sap. PhilcTECI14:16, 8 May 2006 (UTC)[reply]
i am a highschool junior who has enjoyed science for years but has no particular affinity or interest in pursuing it heavily in college or as a job. so i signed up for the harder of two AP physics courses at my high school, which i'm supposed to take after learning calculus, when i haven't yet learned calculus (i'll be doing it concurrently), because the other course doesn't sound as interesting. i'm excited, but the course is supposed to be really tough, and i want to prepare as much as possible for it over the summer. any books anybody'd suggest i read to help me with understanding the physics (or calculus) basics? if i was just to try to learn physics basics on wikipedia, how should i go about doing that? they have a "where to start" section, but it didn't help much because i have no idea what i'm looking for.
thanks so much to anyone who can help
Well.. I'd suggest working from a textbook. Wikipedia is (or tries to be) an encyclopedia, and as such isn't really that great for learning physics and math. (in my opinion) It's better to work from a textbook where the things build on eachother naturally, and where you can solve problems and make sure you understand things properly before moving on. Both are the kinds of subjects where if you skip ahead, you can miss some of the basics and have to pay for it later through lots of confusion. (I've been there plenty of times myself) On the other hand, if you've got a solid understanding of the basics, you can get pretty far on that alone. So I'd suggest seeing if you can get hold of the textbooks you're going to use, and start studying the first couple of chapters or so and build up a solid base. Or you could at least build up your existing skills and make sure that you're completely at home with the level of math and physics you're supposed to know so far. It's always easier to build on a solid base. --BluePlatypus04:16, 8 May 2006 (UTC)[reply]
(Stop edit conflicting me! :p)
Coincidentally enough, I'm going to be taking this test tomorrow (and while I wrote this, my "tomorrow" became "today" >.< ).
Basically, I would comb over the Physics C Course Outline and concentrate on learning concepts. Personally, I needed a little extra effort to grasp concepts in rotation, like torque or angular momentum, and in electricity, like Gauss's law and voltage. (If, while you learn things, you encounter anything that you don't understand and/or is too mathy in Wikipedia, I would come back and ask here for help.) You'll probably also want to be familiar with concepts in calculus, like the meaning of taking a derivative (finding instantaneous rate of change) or an integral (adding up lots of small changes), and what the symbols mean (all the equations you need to know from calc are on the reference table). You might want to know just the concept of a surface integral - but you don't need to know how to do it - so you're not too confused when you see that symbol.
Our school actually takes Physics B and Physics C in sequence - two years in total - so you'll have to cover a lot of ground! (But B has some extra junk that C doesn't have, so that shortens things a bit.) Good luck! :) --AySz88^-^04:18, 8 May 2006 (UTC)[reply]
im taking the bio ap tomorrow.
good luck too
and thanks to both of you
(edit conflict again >.<) Oh, speaking of textbooks, there's a list from the folks at the College Board. Mine is the second one, "Physics for Scientists and Engineers". Don't just look at the first couple of chapters; that would be lethal with something with so many topics. I would look at the first few sections of each chapter, skipping the calculus-heavy parts.
parathyroid hormone (it's a wikipedia entry) - increases blood calcium levels, wheareas calcitonin (in the thyroid) decreases it
Faster Than Light
I've heard that light is the fastest thing in the world and nothing travels faster than it.But instead of saying that light is the fastest thing in the world, why don't we say that light is the thing that's known to be the fastest thing in the universe?I mean, what if there are things that travel faster than light, but it's just that they haven't been discovered?User:Bowei
Instead of "it is known to be the fastests thing in the universe" which implies we are absolutely certain there's nothing faster, I would say "light is the fastest known thing in the universe". By the way: Anything that travels faster would go against a few basic physical theories whose formulas include the constant c for the speed of light. We know it's the fastest because the mathematics say so. - 131.211.210.1107:55, 8 May 2006 (UTC)[reply]
The Theory of Relativity, which has been extremely succesful thus far, says that some very weird things would happen if anything went faster than light. It makes accelerating through the speed of light impossible, since the energy required to even reach the speed of light would be infinite. Hypothetical particles that are always faster than light are called tachyons, and they present problems for causality, as you can read in the article. -- SCZenz08:50, 8 May 2006 (UTC)[reply]
Interaction between things that are faster than light and slower than light would violate causality, and is therefore impossible, so if there is anything faster (eg. tachyons) they are effectively not in our universe, as they can in no way possibly effect anything in the known universe. PhilcTECI11:07, 8 May 2006 (UTC)[reply]
As I understand the theory of relativity it doesn't say that nothing can travel faster than the speed of light it says that nothing can accelerate to a speed faster than that of light. I don't know who but I've heard at least one reputable physisist has theorised about the possibility of traveling faster than light without accelerating beyond it. AllanHainey15:39, 8 May 2006 (UTC)[reply]
Hmm, this is the third time I've brought up Cherenkov radiation in a discussion like this in a week. Maybe we ought to make a Reference Desk FAQ to save answering the same few questions over and over. GeeJo(t)⁄(c) • 18:37, 8 May 2006 (UTC)[reply]
i have heard that a duck's quack does not echo.Is this true?If yes why?
A duck's quack WILL echo. The reason for why this is disputed is because the quack's sound "blends in" sort of with the echo. ALL air waves sent out will hit things in their way. Airwaves WILL bounce back (depending on material and composition), and though losing energy as they go along, WILL be heard as echoes.
Look at the duck article where it links to snopes.com. The scientific experiment didn't seeem that hard to me. --KJ11:54, 8 May 2006 (UTC)[reply]
Microwave data transmission
Just "suppose" I want to transmit 10 Mbit/sec of data across, say 30km of line of sight at microwave frequencies. First, what bandwidth of spectrum would I need? Secondly, what is the typical cost for receiver/transmitter/microwave dish/etc for the pair that are needed (one each end), excluding any masts and installation. Thank you.
I'm no expert in communications technology, but roughly speaking the bandwidth is going to be of similar order of magnitude as the data rate, and I guess probably a bit more to allow for some of the high-frequency components that you'll get in the sharp edges in your signal, so I guess maybe a few tens of MHz. Arbitrary username16:10, 8 May 2006 (UTC)[reply]
I think it would be usually less than 10 MHz (strictly speaking, depending upon a modulation). I have seen 64QAM and 128QAM being used in radio relay links, in this case the bandwidth would be just about a few MHz. But, again, it strongly depends on modulation. --Ring022:25, 8 May 2006 (UTC)[reply]
wierd!
hey 2 all!
In order to understand my question:
Rotate your right foot in clockwise direction while sittin.Simultaneously draw the number 6 with your right hand in air.You will find that your foot has changed its direction!
Now my question:
Why the hell does this happen?????
Anonymous, this is because the brain is conditioned to do things in certain (easy) way. This applies to any new skill you learn (like playing piano, juggling the balls or rotating your parts in the way you discribed). You can overcome this by practicing the act slowly and repeatedly.--Wikicheng11:54, 8 May 2006 (UTC)[reply]
Either I misunderstood the question or I'm a subconscious nitpicker, because it seemed so logical to me why a foot changes its direction while it's being rotated. –Mysid12:04, 8 May 2006 (UTC)[reply]
Oh my goodness, that's cool! Mysid, the question was suggesting that your foot starts tracing a circle in the other direction, ie counter-clockwise. If you trace the circle clockwise and draw the six starting from the top, or trace the circle counter-clockwise and draw starting from the loop, I've found that it really does work (unless you're trying, in which case it's not too hard to do it correctly). It's much like patting your head and rubbing your body, in that it's hard if you're not expecting it, but easy to overcome. Anon, I have can't give a precise reason, but whatever it is, it's cool! — Asbestos | Talk (RFC)12:11, 8 May 2006 (UTC)[reply]
Yes the brain cannot concentrate on the two movements at once, which is where it asks the cerebellum and basal ganglia for help to automate part of the movements. This is called motor learning, and it takes practice. Some combinations of limb movements are learnt from a very young age, but when you think up a new one (such as writing, driving a car, or combining clockwise-foot and anticlockwise-hand movements) it takes some time for your brain and cerebellum to get it right. As suggested by Wikichen, if you try very slowly, maybe first just the foot movement, and gradually increase the pace, you will eventually manage to maintain your clockwise foot rotation while drawing what you want with your hand. Impress your friends and neighbours!--Seejyb12:32, 8 May 2006 (UTC)[reply]
When we observe stuff the wave function collapses but why?
The dynamical evolution of the wavefunction requires that a state with definite value of some observable will eventually evolve into a state which is in a superposition of values (unless it's a stationary state). On the other hand, experience with measurement tells you that if you measure something to have a value, it definitely has that value. If you measure something twice in rapid succession, then you should see the same value twice. Therefore, measurement must change the wavefunction from a dispersed state (which is in a superposition state of different values) to a sharp state with a definite value of your observable. -lethetalk+14:49, 8 May 2006 (UTC)[reply]
Dell Dimension and Pinnalce PCTV does not work properly together
I recently bought a new Dell Dimension 9150 and it works great, except for one problem: my TV tuner card (Pinnacle PCTV 310i DVB-T) is able to scan for channels, but no channels are ever found. I am quite sure that this is some kind of incompatibility between the PC and the card, because the card worked properly in my previous PC. Any suggestions on how to solve the problem? I have search the Internet, and it appears to a be quite common problem. Thanks in advance. --Andreas Rejbrand15:27, 8 May 2006 (UTC)[reply]
If it is such a common problem, why are there no answers? Perhaps you should try asking a Dell tech support representativevs. That's what they are there for. You can find their main support page here. You can also chat with hardware support reps or visit the Dell forums. --Chris
Hardware Support Chat would be great, but I am not allowed to use it as I live outside the US (in Sweden), and I've already tried to ask the question in the Dell Forums. I thought that someone here might have encountered the same problem. --Andreas Rejbrand16:01, 8 May 2006 (UTC)[reply]
Radioactivity at Chernobyl
The Prypiat, Ukraine article claims that it "will take up to 900 years to decay sufficiently to render the area safe" while the Chernobyl disaster article says "rendered land in a radius of hundreds of miles from the plant uninhabitable for at least 100 years." Both are unsourced and many similar unsourced claims appear on Google. Which is correct? How long will it take for the more contaminated areas (excluding the plant itself) to get back to about background levels? Cesium is the major radiation source and has a half life of 30 years, so in 900 years, only 1/10,000,000th of 1% would remain. The map in the disaster article shows the most contaminated areas at "greater than 40 curies per square kilometer" and the background radiation article says that average it is about 2.5 mSv, but there seems to be no way to compare those numbers. Rmhermen15:42, 8 May 2006 (UTC)[reply]
Are ther eany types of chemical reactions that are not redox reactions? They teach about redox reactions as if they are special, but I can't think of any reactions that aren't redoxes. Maybe I'm not thinking hard enough?--Chris15:37, 8 May 2006 (UTC)[reply]
I Verify the above; while there may be some exceptions,substitution and condensation reactions are not redox reactions. --Craiglen16:42, 8 May 2006 (UTC)[reply]
Do all birds lay eggs? I seem to remember from my college orinthology course that there are some species of birds that do not lay eggs? I got $5 riding on this with a friend so if you can prove him wrong. Even if you have to stretch the "truth" a little, that'd be grrrreat.
None of the readily available sources seem to cast doubt that all birds lay eggs. I seem to recall this debate in the past, and that there was a type of bird that essentially produced an egg but it hatched internally so the young exited the body without it... but i don't remember any of the sources for that so it may have been a delusion. There are a few sites that attest to egg laying as a critical feature of birds, and our article on birds has this to say: "Common characteristics of birds include... the laying of hard-shelled eggs". Hope this was the answer you were looking for! --Jmeden200018:12, 8 May 2006 (UTC)[reply]
Kind of a weird one here...the other day I went for a CT scan of my sinuses, and during the procedure I saw strange blue lines moving up and down my vision (eyes closed). Of course I was supposed to keep still, but the appearance of these startled me, and I wondered...if these are seen by many people, why don't they warn the patient? If they aren't seen by many people, what's different about me? --Kickstart70-T-C17:21, 8 May 2006 (UTC)[reply]
The scanner has a "targeting" line of light (usually red) which indicates to the operator what plane (transverse "cut") of the body is being scanned. As your head moved through the scanner, with sequential planes being scanned, the line of light moved down over your face. I agree about the need to tell the person being examined. I wonder though, why you experienced the light as blue - any chance of your having royal blood in your eyelids? --Seejyb20:51, 8 May 2006 (UTC)[reply]
Diesel-hybrid engines in cars?
Diesel engines have been hybridized with electric engines in trains, why haven't car manufactures spent money in putting the efficient diesel-hybrid engine technology into cars?
1. Wouldn't the diesel aspect gives cars the ability to be manufactured for biodiesel, therefore using a renewable resources?
2. diesel engines work on compression and therefore theoretically can last longer, right?
3. hybridizing this with an electric engine would create a relatively clean engine that runs on renewable resources, wouldn't this be a smarter alternative to today's engines?
Yeh they are, but it doesn't work, because all the energy used to move the huge battery discounts any saved by it being hybrid.... PhilcTECI22:21, 8 May 2006 (UTC)[reply]
Diesel Hybrid Engines
Why is it that car manufactures haven't built a car around a biodesiel-electric hybrid engine?
This type of engine (diesel-electric hybrid) has been used in trains for almost a centuary, it's efficient and robust, provides a lot of power (it drove trains) and it would use renewable resources...
-- Stewart Alexander --
Sweden is currently focusing heavily on biodiesel. This resource is rather renewable, and I don't think el-hybrids will be seen until a few years ahead, at least a decade. After all, you have to create a market for the normal car before you can sell hybrids.
Biodiesel is simply a fuel used in ordinary diesel engines - no new cars have to be developed to use it and Europe has a rather large market for diesel cars already, unlike the U.S. Rmhermen20:02, 8 May 2006 (UTC)[reply]
A gas hybrid saves 20% in the city, and almost nothing on the highway (air resistance dominates). Current diesels already exceed that, but are dirty (I saw a brand new Jetta TDI belching!). New low-sulphur diesels should be much cleaner, so right now, a diesel hybrid doesn't make much sense. --Zeizmic21:37, 8 May 2006 (UTC)[reply]
The diesel-electric Opel Astra should be coming out this year. The European diesels put out very little exhaust fumes. The car can apparently do 1-100 km/h in 8 seconds, and gets 60 mpg (claimed 25% better than diesel alone?). The advantage of hybrids is in short distances. See [hybridcars.com]. I personally like the idea of using butanol as a sustainable biofuel. --Seejyb22:22, 8 May 2006 (UTC)[reply]
Hybrids cars don't work, they waste more energy than normal cars, as the battery adds so much weight to the car, scientists don't think hybrid cars will be worth the difference until a viable way of storing a lot of electricity in a small space is cracked, the current hopes lie in the hydrogen cell. PhilcTECI22:24, 8 May 2006 (UTC)[reply]
Visual Basic .NET
I need some help from someone good with Visual Basic.NET edition, as I learned to program in VB6, and I'm having a couple of problems with my .NET coursework project, and as usual trying to get a relevant answer out of MSDN is like trying to squeeze water from a stone.
Number 1; In VB6 you can print text strings into a picture box object using:
To read records from a .txt file, the array keeps messing up with the quote marks around each field in the record. With the input procedure, I can type, in their respective text boxes, the data: 123, Smith and John. My program writes this record to the file in the format:
"123", "Smith", "John"
The array reads the quotes as part of the field, as if the data I entered was: "123", "Smith" and "John". This messes up the Search procedures, as 123 and "123" is different. Manually opening the txt storage file in notepad and deleting the quote marks makes it work, so is there some way to stop the record writing code from adding the quotes, or some other way of making the array take out the quotes?
I recall being told that it is possible, but would recquire a radically different atmosphere, as C02, on which so much of the life on this planet depends on is a gas, however silicon dioxide, is sand, which is less easy to breathe. So hypothetically yeh, but then shouldn't everything in group IV be the same... PhilcTECI22:27, 8 May 2006 (UTC)[reply]
DSN in artic/antartica
i was thinking how much of an advantage/disadvanatges would there be to putting communication telescopes (like the deep space network) in the artic/anartica? i mean all the equipment will be kept cold easily, your a long way away from any man made sources of interfernce and u could in theory point the telescope in any direction, are there any other things i missed? and what problems are there?
Logistic problems and technocal problems with the dish aside, the ecliptic would be too close to the horizon. It is extremely expensive to shoot a spacecraft in an orbit inclined to the ecliptic, this has been done once and required a gravity assist from Jupiter. Besides, most spacecraft are shot to planets anyway. So for all practical purposes the antenna would be useless.
IP Address
If I know someone's IP Adress how do I find out who it is? Someone insulted my friend and all I have is their IP Address. Þanks *Max*21:25, 8 May 2006 (UTC)[reply]
(once again, Zeismic beats me to it) Usually it's impossible - IPs for private computers are assigned by the user's internet service provider (ISP), and some even use dynamic IPs (ie your IP changes every time you log on). At most you'll be able to get the name of the ISP, and maybe the town/city. It's different if the IP belongs to a website, in which case, you'll be able to get the name/company it's registered to. The tool you need is called a whois, I always use the one at DNSStuff.com, and it works pretty well. Try it, you may get lucky. — QuantumEleven21:35, 8 May 2006 (UTC)[reply]
Doubt it as having aids, means you can't fight off any diseases, so someone with Aids probably also has just about every other disease they can get, so they would just be needlessly infecting already weak people with more viruses and illnesses. PhilcTECI22:45, 8 May 2006 (UTC)[reply]
No, hospitals don't intentionally give anyone HIV positive blood. HIV-positive people are asked not to donate blood, and any donated blood that tests positive for HIV is discarded. - Nunh-huh23:00, 8 May 2006 (UTC)[reply]
Mac Davis] ⌇☢ ญƛ. 07:53, 1 May 2006 (UTC)
Mac Davis] ⌇☢ ญƛ. 07:58, 1 May 2006 (UTC)
