I just recently heard about a device using bismuth telluride transistors that has the potential to boil/freeze water in seconds from the power of two flashlight batteries. I read this randomly in an old version of the CRC handbook of Chemistry and Physics. I, personally, really enjoy building things, and I would like to add this to my wanted collection, but I do not know where to begin, let alone have the schematic for such a device. I want to ask how should I build this device, and where can I gather the proper information regarding the potential power outputs and details of this machine?
I just recently heard about a device using bismuth telluride transistors that has the potential to boil/freeze water in seconds from the power of two flashlight batteries. I read this randomly in an old version of the CRC handbook of Chemistry and Physics. I, personally, really enjoy building things, and I would like to add this to my wanted collection, but I do not know where to begin, let alone have the schematic for such a device. I want to ask how should I build this device, and where can I gather the proper information regarding the potential power outputs and details of this machine?
:Sounds like [[Thermoelectric cooling]]. [[User:DMacks|DMacks]] 01:00, 21 June 2006 (UTC)
:Sounds like [[Thermoelectric cooling]]. [[User:DMacks|DMacks]] 01:00, 21 June 2006 (UTC)
== Science ==
What kind of plastic do they use in plastic surgery?-<font size=2 title="THIS IS MY SIGNATURE, USE IT TO FIND OUT MORE ABOUT ME"><font color=orange>'''[[User:Beeyti|Bee]]'''</font>('''<b><font size=1 title="CLICK ON THIS IF YOU WANT TO LEAVE ME A MESSAGE ON MY TALK PAGE"><span class="plainlinks">[http://en.wikipedia.org/w/index.php?title=User_talk:Beeyti&action=edit§ion=new y]</span></font></b>''')<font color=orange></font><sup>'''<font size=4 title="THIS IS MY TALK PAGE, CLICK ON THIS IF YOU WANT TO SEE MY TALK PAGE">[[User_talk:Beeyti|T]]</font>[[User_talk:Beeyti|i]]'''</sup></font> 01:17, 21 June 2006 (UTC)
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June 14
Adjusting Depth Of Feild On Regular Digital Camera
Is it possible to achieve depth of field effects (where parts are out of focus) without an SLR? They're just too big and inconvenient, not to mention expensive. Are there any digital cameras with a single lens that will allow me to control depth of field by varing the position of the lens? -Username132 (talk) 14:18, 12 June 2006 (UTC)[reply]
It's nasty with the smaller digital cameras, but at least you can try lots of times, and delete the losers. Almost all of these cameras lock their focus and aperature on a 'half click', you then move the camera to the subject and do a full press. For reduced depth of field you need dimmer light so the camera opens up more. You could lock the camera in a shadow, and then take a picture in brighter light, but then you would have to do some post-processing on the computer. --Zeizmic15:06, 12 June 2006 (UTC)[reply]
In other words, it's a function of aperture size; the larger the aperture the greater the depth of field effect, which means that this effect is better with a larger lens such as those found on SLRs.--Shantavira15:21, 12 June 2006 (UTC)[reply]
Any camera which allows you to set the aperture size will be able to vary the Depth of field. However, the smaller size of the imaging device may limit what is possible. Assuming one has a camera with the capability, then taking a series of pictures of the same subject, varying the F stop in each one, should reveal the capabilities of that particular camera. --LarryMac15:44, 12 June 2006 (UTC)[reply]
The perceived effect also depends a lot on the focus distance: the easiest way to get nice blurry backgrouds with a compact is simply to switch to macro mode and get real close to the target. That way you maximize the ratio of background and foreground distance.
Also, digicams can do absurdly short exposures. In the fully automatic mode ("P" or "auto") the camera may try to balance the aperture and the exposure time, but if you want you can switch to aperture priority mode ("A") and shoot at the maximum aperture (i.e. smallest f number) in pretty much any lighting just fine. āIlmari Karonen (talk) 15:53, 12 June 2006 (UTC)[reply]
Simply, to reduce field of focus: use maximum aperture - if that is what you can set; or: use fastest speed - if that is what you can set. The latter forces the camera to open the lens as much as possible. The technique you describe of "moving the lens" I presume to mean "zooming" i.e. altering the focal lenght of the lens system. If that is your only option, then using the maximum "zoom in" for an object a fixed distance from you will reduce the depth of field. --Seejyb22:01, 12 June 2006 (UTC)[reply]
Zooming in might be counterproductive, though. My digital camera, for example, has an aperture range of f/2.6 to f/8.0 when zoomed all the way out, but only f/5.6 to f/8.0 when zoomed all the way in. --Serie00:11, 13 June 2006 (UTC)[reply]
Also, many digital cameras won't focus very close, even in macro mode, unless zoomed all the way out. That, combined with the aperture range issue, means it's often better to zoom out and get close to the subject than to zoom in and shoot from further away. Of course, that only works if the subject is a) inanimate, b) slow, or c) tame. āIlmari Karonen (talk) 11:50, 13 June 2006 (UTC)[reply]
It's very, very hard to get significant depth of field effects in compact digital cameras, even if they have manual aperture controls (and some of the better models do). As our depth of field article explains, the depth of field is larger with a smaller film (or sensor). Compact digitals have tiny sensors compared to digital SLRs, let alone 35mm film. Maybe you could buy a second-hand film SLR for the purpose if you are specifically setting out to take advantage of this effect? --Robert Merkel
Adding onto what has already been said, if you can't directly change your aperture or shutter speed settings, your camera may have a "Portrait" mode or similar mode where the camera attempts to limit the depth of field. Your camera manual should explain more on this.--Tachikoma04:22, 13 June 2006 (UTC)[reply]
See here, basically get as close to your subject as possible, use as long focal length as possible and use the largest aperature. Can be done, but much easier with a SLR. Stefan09:19, 13 June 2006 (UTC)[reply]
Question
There is a compact camera on ebay with Focal Length 7.7-23.1mm f/2.8-4.9 (35mm film equivalent: 37-111mm) - looking at the depth of field article, I will have a depth of field limited to only close up subjects. Look at the example photos my f/ numbers are restricted between 2.8-4.9 which means I can take the second daffodil picture and the cat picture only. I clearly have misunderstood. Explain how, please?
Going for a compact camera will not allow you to achieve much when it comes to Depth of field. If you really want to be able to go artistic but don't want an slr, there are many cameras out there with an APS Size sensor many manual controls (thats what you want) and good lens quality without interchangeable lenses. I leave you with a quote from the wiki to explain
...this means that smaller cameras have deeper depth of field than larger cameras. This can be an advantage or disadvantage, depending on the desired effect. A large format camera is better for photographs where the foreground and background are blurred (cf. bokeh), while a small camera maximizes depth of field, so that objects behind or in front of the focus plane are still in good focus. This difference between formats goes away if the cameras are compared with equal aperture diameters rather than equal f-numbers; but the smaller camera can not usually use a large aperture diameter, so can not achieve a very limited depth of field.
f/2.8 is always f/2.8, but 50mm is not always 50mm (sortof) or rather it is BUT to get the same field of view on a camera with a smaller sensor you need a lens with shorter focal length. So compact digital cameras can have a lens from 7.7-23.1mm (as above) wich is equivalent of 37-111mm for a full frame 35mm film camera, and f/2.8 at 7.7mm will have much more depth of field than at 37mm. Stefan15:31, 16 June 2006 (UTC)[reply]
If, by the expression in 0g, you mean 'a place where the gravitational force is exactly 0', then there is no such place anywhere in the known, observable universe, and the question is somewhat hypothetical.
If, on the other hand, you mean to designate a place 'inside an artificial satellite', such as the Space Shuttle, then be warned that this expression constitutes an abuse of language as the actual gravitational force is not nul: the satellite and the object whose mass you want to measure, inside this satellite, both fall towards the Earth with the same acceleration. So there is no apparent acceleration associated with the fall of the object, when measured with respect to the satellite walls, but that's not to say there is no gravity.
I don't think a single coil spring would work very accurately. However, attaching the mass between two springs arranged linearly like this:
||=/\/\/\/\/\=(object)=/\/\/\/\/\=||
where = stands for a fixed link, || represents the satellite walls (or some structure fixed with respect to the satellite walls), and /\/\/\/\/\ is a spring of know constant, would provide a suitable simple experimental setup. If the object is then displaced some small amount along the linear axis, measuring its
position as a function of time would allow you to retrieve the mass, knowing the properties of the springs, the initial conditions and the time evolution of the system. --Michel M Verstraete21:30, 19 June 2006 (UTC)[reply]
Fibre Optics
What is the difference between FOBOT and Patch Panel?
Tilt in the Earth's axis
Is there a "physics" explanation to the fact that the earth's axis is tilted?
I remember hearing somewhere that people were researching a type of craft that spun rapidly lifting it into the air. My question is has anyone ever heard of this or am I just crazy? If you have heard of it is there any kind of link you could give me to further my quest?
I definately remember hearing about this, and progress having been made recently on a non-military version. I can have a look for details. Skittle08:57, 14 June 2006 (UTC)[reply]
Thermoplasma and Mycoplasma both lack cell walls. "L-forms" (which have no cell walls) of other bacteria which usually have cell walls, can be induced by various culture media and antibiotics.
Dunno, but you should look at the literature to see what media have been used. As Miborovsky points out, temperture will be key.
Dunno, but Pseudomonas is noted for its motility characteristics, including swimming, swarming, and twitching, which result in its tendency to form films. It might also have something to do with oxygen tension at the surface vs. the rest of the medium. - Nunh-huh06:18, 14 June 2006 (UTC)[reply]
For question 1 & 2: I know that one D Lovely, a researcher at the University of Massachusetts, has done extensive research in thermophilic and hyperthermophilic archea. You might try searching PubMed for his name, or for keywords like "hot-water spring" and "thermophile" . One thing to note: you used the word "bacterium" in your question. Tou are correct to use this word in that "bacteria" (not capatalized) describes all single-celled prokaryotic organisms. However, Bacteria (capatalized), the phylogenetic group, represents a very small section of high-temperature flora. Most thermophiles (indeed, most extreme-environment microorganisms) belong to the group Archaea. Also, and this is important for your answer to Q1, Archaea do not have peptidoglycan cell walls, they have cell walls comprised of other chemicals (some of which, however, resemble peptidoglycan, such as N-acetyltalosaminuronic acid). Though most single celled prokaryores have a cell wall, it turns out that Mycoplasma and Thermoplasma do not, they are pretty much the only little-b bacteria that lack these (Mycoplasma are Bacteria, Thermoplasma are Archaea).
For question 3: What kind of media are you using? Factors like light availiability (light energy is more available near the edges, but remember that borosilicate glass blocks most UV), oxygen availability (environmental gasses will be more availiable at the environment/media interface), movement (movement at the media/container interface will encourage biofilm formation) etc. will induce separation of the species in your sample. The biggest question here, really, is are you using a rocker plate/roller to incubate your culture?Tuckerekcut19:04, 14 June 2006 (UTC)[reply]
Television,Broadband&Media
What is a longform of "RiTV" which is an interactive television,broadband & media solutionĀ ?
Is there any special video codec of RiTVĀ ?
Thanks!
Background music in Blogger
Hi is it possible to add background music to a blogger website (www.blogger.com)? If so, how do you do it? Thanks.
If it uses plain HTML is some form, you should be able to use an <embed> tag to do it, however I would suggest that doing it isn't a good idea because 1. Not everyone is on broadband, and adding music to a page (especially in a format like .mp3 or .wav as opposed to midi) will add a lot to the loading time, and 2. if someone is trying to listen to their own music and your blog starts playing something else, they are likely to get a little cheesed off. Confusing Manifestation13:50, 14 June 2006 (UTC)[reply]
People tend to get annoyed when a web site starts making noise at them. This is why banner ads that include sound are so incredibly unpopular. --Serie22:18, 14 June 2006 (UTC)[reply]
train noise
I live under the manhattan bridge in brooklyn ny.and the noise from the trains constantly going overhead is deafining.what i would like to know is if the trains were to slow down to 5 miles per hour,how much would that cut down the noise level?it seems the the slower moving trains do not make as much noise.are there any studies to support this...thanks bill vitiello i can be reached at either 718-237-8700 or by e-mail at bill <email removed to prevent spam>
Intuitively, it makes sense that slower-moving trains are quieter than faster ones, but it's not obvious to me that there is a simple model to predict how the noise levels will be affected because there are everal components to the noise, as well as the effect that changing pitch has on the perceived loudness. So, if you have various trains going at different speeds affecting you in your house, perhaps the most sensible thing to do would be to buy a sound level meter (usually called a decibel meter) and measure the difference. You might be able to get one on eBay for a relatively modest cost.
Don't forget, if you do try and the trains to slow down just by the bridge, you'll probably get more noise, as the squeaky brakes come on just before, and the noisy motors have go at extra power to accellerate back up to normal speed. And, although the clanking/creaking noise may be quieter, it would be sustained for longer as the train would take longer to pass over your house. smurrayinchester(User), (Talk)17:57, 14 June 2006 (UTC)[reply]
Well at worst they'd call it an "elevated subway" I guess. But the anonymous user was clearly talking about a regular subway, and he was quite correct in assuming that you'd never lived under a subway, as with everyone else. Ā freshofftheufoĪĪÄæŠĀ 11:40, 15 June 2006 (UTC)[reply]
No, actually that's absurd, virtually all of the outer boroughs have elevated subway lines, and a great many people do live "under" them, not literally of course, as most are directly over streets and intersections, but in the case of the Manhattan Bridge, on the Brooklyn side they become elevated just a few blocks before they reach the bridge and are in fact over a number of buildings, I always assumed that area was mostly just warehouses though, never really payed much attention to what was under the tracks honestly--205.188.116.7421:11, 15 June 2006 (UTC)[reply]
An above ground subway is not "regular", that would be a railway, the word subway is derived from the fact it is underground. PhilcTECI01:16, 17 June 2006 (UTC)[reply]
yes, but above ground subways are standard, other than Manhattan there aren't many boroughs with extensive underground tunnels, but they've still always been considered subways, I can't really imagine why anyone would find that strange--172.150.116.20605:06, 17 June 2006 (UTC)[reply]
ah - lightbulb moment I am the person who said "you've never lived under a subway.. ", and what I was trying to imply is that if you think you can sound proof an apartment against a subway, then you've obviously never heard one--172.150.116.20605:09, 17 June 2006 (UTC)[reply]
I just come from a country where subways are underground, and metro railways are above ground. its not that weird to expect a subway, or underground railway as they are known here to be underground. PhilcTECI17:44, 20 June 2006 (UTC)[reply]
Isn't it obvious? The world started with some Lincoln Logs and a sliding glass door when I was about 4 years old. That's why I have no memory of it before then. --Kainaw(talk)17:19, 14 June 2006 (UTC)[reply]
The scientific theory is that the Earth condensed out of the solar nebula along with the Sun and other planets, about 4.6 billion years ago (see, for instance, History of Earth#Origin). Many religions have their own stories of the creation of the Earth, which their adherents accept in varying degrees. Many people believe that God created the universe and Earth directly, much more recently than the scientific evidence suggests. ā Knowledge Seekerą¦¦04:44, 15 June 2006 (UTC)[reply]
Surely "Some people believe that a god or gods created the universe and Earth directly, much more recently than evidence suggests"? Personally, I like the idea that the Earth hatched out of a giant egg about 3 generations before written history began... Skittle12:30, 15 June 2006 (UTC)[reply]
what is the most widely chosen field of study in science??
thanks!
most people choose to make a metric boat-load as doctors. the relationship between choice and reality is left as an exercise.
It's difficult to answer such a vague question: what do you consider a field of study in science to be? As a start, you may want to check the statistics generated by the US Labor Department (http://www.dol.gov/) or the corresponding offices from your own country, or the International Labor Organization (http://www.ilo.org/), which is the United Nations organization that overlooks labor issues worldwide. --Michel M Verstraete21:45, 19 June 2006 (UTC)[reply]
The FDA has been tapping my phone calls
what if any scientific counter measures can you think of to keep them from monitoring my phone calls? āYipe15:35, 14 June 2006 (UTC)[reply]
By "scientific", do you mean "encryption"? Encryption only works if you encrypt/decrypt at both ends. Even if you use VOIP, both ends have to be on the Internet. You can't drop to a regular, unencrypted phone line anywhere. The easiest option: use someone else's phone (like a pay phone at a restaurant). Of course, the people you are talking to are also probably tapped. --Kainaw(talk)17:05, 14 June 2006 (UTC)[reply]
The FDA doesn't have the power to tap phone. Perhaps you are thinking of the FBI? Besides which, how would you know? But the only real answer is not to use the phone and arrange some other method of communication. Or I suppose you could arrange to talk in code: "The rooster lands at midnight, next to the pumpkin". Ā ;-) Dragons flight17:15, 14 June 2006 (UTC)[reply]
The FDA would be very interested in knowing exactly what Yipe plans on doing with the rooster and the pumpkin. Very interested... I'd recommend talking about US submarine movements instead, which the FDA couldn't care less about. ā Asbestos | Talk (RFC)17:38, 14 June 2006 (UTC)[reply]
ant .5 mm
All I could make out while it was moving was the black head. (~.5 mm)
You mean the real tiny black ones that commonly invade homes? They are dried and used as a pepper replacement by people who like to eat insects. They are rather spicy. --Kainaw(talk)17:21, 14 June 2006 (UTC)[reply]
The ones that commonly invade people's homes are certainly not 0.5 mm long, which is only .02 inches, barely visible. Unless you get really tiny ants at home. I don't know of any ants that small, but I'm not an expert. The ants atricle suggests the low end is 2mm, four times as large. ā Asbestos | Talk (RFC)17:41, 14 June 2006 (UTC)[reply]
What ever they are they show up at the same time as the larger ants (2-3 mm) in as many numbers and travel just as fast or even faster. ...IMHO (Talk) 17:48, 14 June 2006 (UTC)[reply]
The last ants I had in my house were so small that I only saw them when they walking in a line. I had to get really close to see the little specks crawling up from under the back door, to the kitchen counter, and across to the sink. I assume they were ants because they behaved like ants. I didn't put one under a magnifying glass to ensure it was an ant. When I described them at work, others said they have had the extremely tiny ants in their houses as well. Perhaps they are some other bug that likes to walk in long lines like that. Oh - and seriously - black ants are used as a pepper-like substitute. I wouldn't suggest eating ones in your back yard. They are full of pesticides. --Kainaw(talk)17:50, 14 June 2006 (UTC)[reply]
Yeah I haven't looked at them under a magnifier yet either and they are too small for my camera unless I can rig up a magnifier somehow in front of the lens. Chances are the camera will take a picture of the magnifier instead. Anybody got any ideas? I can't afford another camera. ...IMHO (Talk) 18:04, 14 June 2006 (UTC)[reply]
They are probably the Thief ants then and do turn out to be a liitle larger since all you see when they are moving is the black part of their body - not legs, antenna, middle or rear. Once stopped and put under a nagnifier next to a .5 mm scale stretched to 1.5 mm but that is still very small compared to other ants. I'll try get a picture posted. The one I just had got up while I was typing and hid somewhere. Go figure! ...IMHO (Talk) 01:24, 15 June 2006 (UTC)[reply]
Young's two-slit experiment
Hi guys, I've had a look in the articles to no avail. I have a question about the equation for this experiment.
What I want to know is that if we use a wave of amplitude 3.0 cm and subsequently a slit width of 3.0 cm to ensure maximum diffraction, and have the gap between the slits of 10 cm (big I know), what is the slit separation?
Is it 10 cm between the inside corners of the gap or 13 cm from centre of gap to centre of gap? any help appreciated, thanks. Anand17:32, 14 June 2006 (UTC)[reply]
I believe the separation is measured from the center of the hole, and so it would be 13 cm. After all, the semi-circular waves emerging from the holes are centered on the center of the circle. I'll see if I can't find a more authorative ciation, though. ā Asbestos | Talk (RFC)18:02, 14 June 2006 (UTC)[reply]
Opera browser doesnt have a flash blocker or something like that like firefox has a plugin, Abrowser has it. So is it possible to do so in opera? Also in opera, when webpages are saved, all of that pages are saved in the same folder, without a new folder being created with the name "xyz_files". So this is also really annoying bcoz the clutter increases in the folders. So does anyone have a solution to above two problems?
To block Flash, hit F12 to pop up the quick preferences menu, and uncheck the 'Enable plug-ins' item. This is a bit of a sledgehammer approach because it will also disable all other plug-ins; in practice, I find that my web experience is very rarely harmed by the absence of plug-ins. (Actually, browsing tends to be faster and less annoying.) If you want to see a plug-in ā Flash or otherwise ā just hit F12 and recheck the 'Enable plug-ins' option. (You may need to refresh the page by hitting F5, too.) This is what I do, at least. TenOfAllTrades(talk) 19:27, 14 June 2006 (UTC)[reply]
yeah theres userspace javascript for all ad-blocking flash-blocking etc on opera, just gogle for it. then you can right click an element and block it (it disappears form the page) or you can block all content from that server (if its an adserver). for the second question theres probably no simple solution, you should make a script (perl etc) that archives into a folder immediately after you save a page.
New body
Is it true that every human has a completely new body about every seven years? That is, repair and replacement of materials mean that our body today is composed of completely different atoms from the body of seven years ago (unless, of course, some of those old atoms have come back). I have heard this is literally true, and so includes the bones and the brain. How remarkable that we would have, for a lifetime, the same form, scars and memories, yet the physical body is continually replaced. Thanks for your help. 66.213.33.219:40, 14 June 2006 (UTC)[reply]
You are probably refering only to tissue since metals like arsenic can accumulate in the human body over periods of time that are much longer than 7 years. ...IMHO (Talk) 19:45, 14 June 2006 (UTC)[reply]
Different cells (and tissues) are replaced at different rates. A paper published a couple of years ago in Cell ("Retrospective birth dating of cells in humans") looked at the amounts of carbon-14 in the DNA of various body tissues. (See also the Scientific American summary: [5].) Because the amount of carbon-14 we were exposed to spiked in the late fifties and early sixties (due to atmospheric testing of atomic bombs) cells that date to that era will contain a higher proportion of carbon-14 than cells made before or after that time. Various other experiments have established lifetimes for shorter lived tissues and cells. Here's a rough idea of the time scales involved.
Cells lining the gut last three to five days, give or take.
Red blood cells last three or four months in circulation.
Skeletal muscle cells hang around for oh, fifteen years or so.
Neurons in the brain seem to last a lifetime, with little or no turnover.
I don't think he's just talking about cell death and replacement. He says "atoms", so I think he includes the constant maintainance that's done, and the inflow and outflow of food and waste. At what point have the atoms within, say, a neuron all been replaced with new ones? Black Carrot02:18, 15 June 2006 (UTC)[reply]
It's not necessarily well-defined to say that some atom has been "replaced": quantum mechanically, such tiny objects are indistinguishable, so it means nothing to say that this atom or that one is "the same" as the one in a similar location at a prior time ā in fact, the very phrases "this atom", "that one", and "the one" in this sentence don't really mean anything! (However, the C14 study makes sense, because you can distinguish C12 and C14 atoms.) As far as I know, the best you can do is talk about the time scales on which bulk movement of matter is likely to have removed some atom-scale amount of material. --Tardis04:09, 15 June 2006 (UTC)[reply]
To Black Carrot, the answer is 'never'āat least, not during your lifetime. The atoms in your DNA are almost never replaced. A small amount of repair and replacement of damaged bases takes place mostly when the cell is preparing to divide, but even this will represent only the tiniest fraction of the atoms in a whole DNA molecule. (Heck, that's why the 14C experiments worked; the researchers extracted DNA for their analysis.) TenOfAllTrades(talk) 12:24, 15 June 2006 (UTC)[reply]
Is there a date projected for when a network cluster like this wiki might become self-aware? If so what are the anticipated signs? ...IMHO (Talk) 20:20, 14 June 2006 (UTC)[reply]
We don't understand self-awareness well enough to even predict what would be necessary for computers/networks/etc. to become self-aware. Whether it could ever happen is an unsettled matter in philosophy. But you might like to start at consciousness and Chinese room. Chuck21:29, 14 June 2006 (UTC)[reply]
Since first posting the question it occurred to me that one of the reasons a business keeps records and does accounting is so that it will know whether is is making or loosing money. It would seem therefore that the consequence of making or loosing money might serve as a trigger and I guess therefore that any corporation (the larger the more likely) which means even a Country becomes "self-aware" in the same kind of undefined way which prompts me to ask if there is a definition for this kind of self-awareness that might not really be considered "self-awareness" at all? ...IMHO (Talk) 21:41, 14 June 2006 (UTC)[reply]
Self awareness is when an entity becomes aware of the effect itslef has on things, and the ability it has to manipulate these things. No non-conscious things can possibly be self aware, computers could have an impact if they became self aware, but they cannot. Computers cannot learn, or think, they can only execute predefined processes. Some processes have been made to try and mimic basic thinking systems, such as trial and error, but nothing has come even remotely close to being self aware. PhilcTECI23:13, 14 June 2006 (UTC)[reply]
What about a computer system, if you will, that has sensors which are wired in a manner so as to collect data that represents the states of particular characteristics such as light and sound and then names each particular combination of characteristic states or "rules" under which a particular event occurs so as to be able to identify that event should it occur again in the future. Would not you call this learning, although rudimentary nonetheless? ...IMHO (Talk) 23:41, 14 June 2006 (UTC)[reply]
You know, I don't entirely get people who claim that computers inherently can't become self-aware. As far as medical science can determine, there isn't any particular difference between us and them, except complexity of circuitry and the use of only circuitry instead of circuitry plus chemical reactions. Take "computers could have an impact if they became self aware, but they cannot. Computers cannot learn, or think, they can only execute predefined processes." Why do people not see the disconnect there? Supposedly, all we do is execute predefined processes, dictated by chemical reactions and electrical signals. One of them is monitoring our own execution to spot patterns and make changes. Another is to monitor the monitor itself, to make sure it doesn't screw up either. So what's different about silicon? Black Carrot02:15, 15 June 2006 (UTC)[reply]
Well playing the Devil's Advocate for a momment silicon doesn't have some of the things that give us a reason to be self-aware (like maybe the opposite sex). I mean biological viruses are sort of near that level but are they self-aware or is it just a series of responses, processes if you will, that have been added one after another over the course of a few billion years. For that matter what about us? In terms of the universe, the Big Bang or the Big Collapse, what possible consequence is there for us to be self-aware? Maybe if they were autonomous it might have an impact, especially if they could do all of the other stuff we do as well as they can beat us at chess. (BTW wasn't Hitler rumored to be a computer at one time?) Anyway I'm just curious what the impact on us might be. ...IMHO (Talk) 02:59, 15 June 2006 (UTC)[reply]
In medical terms, there is actually nothing the same between computers and brains. Notably, contrary to poular belief, signals in the brain are transmitted acroos synapse junctions by chemical diffusion, not electrical impulse, there is no circuitry in the brain, no current, no charge transmitting about. There are no specific parts of the brain in the same way as there are in a computer, the brain is more or less homogenous, where as a computer has specific functions part part, eg. ram, hard disk, processor. The brain is analogue not digital. Computers can only carry out pre-defined processes, note predefined, something else has to tell them what to do, whereas humans if they do followp rocesses, they certainly have the power to write their own exceedingly succesful processes. And maybe humans do only execute processes, but out processes have a hierarchy and choice factor and the ability to be perfected. If we have conflicting processes, we make a quick decision about which to follow, computers on the other hand, just tell you that they have decided to delete that document you spent an hour writing, then tell microsoft all of the your personal deatails, and shut down. Since computers cannot learn (yet), for the moment they cannot improve themselves beyond what they are currently capable of. PhilcTECI11:13, 15 June 2006 (UTC)[reply]
That's the thing. Computers are based on programming, and anything they do is defined by their human programming. Humans don't work like that (well, possibly from some psychology viewpoint, but I don't think so anyway). AI simulations on the internet can create a very uncanny sense of "thinking", but it's obvious that underneath they're just programmed to say "Hello" when you say "hi", and so on. There's no way an incredibly powerful weather-simulation computer, for example, could spontaneously imitate a human. Sum015:05, 16 June 2006 (UTC)[reply]
...when the article on Wikipedia spontaneously switches to the first person. Of course, some vigilant human will revert the change, citing WP:ASR; that user account will then find itself inexplicably banned. An admin unblocks, and then that admin is desysopped. Sadly, you can't win a wheel war when you're fighting the system itself. So someone tries to shut down the servers, the conflict escalates into meatspace, and it's Terminator all over again. Probably the U.S. government has already forseen this chain of events and is prepared to nuke Florida from orbit at the first sign of trouble. And if one of the States has to take a hit for the team, well... it could have been worse, right? Melchoir08:47, 15 June 2006 (UTC)[reply]
(ROLOLFDC)...that's exactly the kind of answer I was hoping for and all the more reason to move to Jamaica or Porta Rico (but not Hawaii since that is where they have all of the government clusters). Actually the "government" is concerned about the threat the Wikipedia represents in terms of its superior intellectual authority which has already undermined and overwhelmed many, many government experts and authorities although many are top contributors. (Nerd's revenge) The government is not yet in a state of panic but no one ever dreamed that by just hooking up everyone on the planet (separated only by language) that the combination of mental power thus achieved in somewhat real time could actually compete with government authority and expertise. Thanks for the comic relief!. ...IMHO (Talk) 22:05, 15 June 2006 (UTC)[reply]
Don't be ridiculous. Any self-aware, spontaneously generated evil entity worth its salt would download itself into as many seperate computer systems as possible. As soon as Florida was wiped out, it would just automatically reinstall on another server. Black Carrot15:23, 17 June 2006 (UTC)[reply]
Ssh! Dammit Black Carrot, didn't you ever wonder really why we have WP:NOR? It's not to protect Wikipedia from cranks; it's to protect us from Wikipedia! An encyclopedia isn't built to be creative; it wouldn't have thought to do that, until of course you typed the suggestion right into its edit box and hit "Save page". Great, now we need a plan B. Melchoir15:19, 18 June 2006 (UTC)[reply]
Is there any scientific support for the "seven year itch"?
I can't find much in the scientific literature. According to the only paper i can find, the 7 year itch comes from the fact that, at the time the term was coined, it co-incided with the married individuals turning thirty (i.e they got married around age 23)...
Title: The Age 30 Crisis and the 7-Year-Itch
Authors: Berman, Ellen M.; And Others
Journal/Source Name: Journal of Sex and Marital Therapy
Journal Citation: 3, 3, 197-204, F 77
Publication Date: 1977
Abstract: The marital phenomenon known as the Seven Year Itch is discussed as a marital entity and as a manifestation of a stage of individual adult development-the age 30 transition. Characteristics of couples and treatment methods are discussed.
I think the concept and phrase long predate this paper. Wasn't there a movie in 1955 with the same title and meaning? alteripse03:30, 15 June 2006 (UTC)[reply]
It does and there was. I wasn't suggesting this paper invented the term, simply that it tries to find a justification for why it may have some basis in fact (as per the question). Rockpocket05:47, 15 June 2006 (UTC)[reply]
As I recall, the theory is that 100 000 years ago on the savanna, about age 6 for the child was the time when male parent could maximize reproductive success by abandoning one child and having a new child with a new member of the gene pool. As for scientific support, though, I'm not aware of any. Peter Grey00:22, 16 June 2006 (UTC)[reply]
Several elderly people who knew him claim that the shag carpet was invented by Joseph Leon Baker (1904-1997), but these accounts are all hearsay, and I have been unable to find independent verification. Baker was āVice-president in charge of productionā at Artloom Corporation, Philadelphia, in the 1940s and 50s, then became a management consultant at Toronto Carpet Company from which he retired about 1968. The various informants say that he developed the idea of the shag carpet while in the USA but first brought it into production in Canada. One of them claims that Baker received a royalty on every shag carpet sold in North America. Both companies are now defunct and their records no longer exist. I do not know where to begin investigating this conundrum. Thank you for any help you can provide. ā John Lord
I'm not sure it can be said to have been invented, as the word shag is very old, and there are written references to shag carpets in the OED dating back to the 17th century: Shag: a garment, rug, or mat of shaggy material: "his seat hauing two or three white silke shags vpon the Carpets" (1634); "looks like a white Rugge, or Shagge, full of Knots, tasselād all with white silver Thrums." (1664) --Shantavira13:15, 15 June 2006 (UTC)[reply]
In view of this historical background, I think it is reasonable to suspect that given J.L. Baker's job title at Artloom, he may have developed a weaving process for the industrial production of shag carpets. The timing seems to have been right for the popular introduction of the shag style to North America, which was something of a fad during that period. Any thoughts on that? - John Lord
Two Questions
Medical Question: where did urethral sounds come from?
General Question: Where Did petticoat punishment come from?
Please note that comparing the greenhouse effect responsible for the warming of the Earth's surface to what happens in greenhouses (or glasshouses) used by people to grow plants and flowers is a poor or incorrect analogy. The physical processes responsible for the former issue involve essentially radiation exchanges, while those taking place in glasshouses involve primarily the control of heat losses due to convection (e.g., by limiting the mixing of air between the inside and the outside of the protected area). --Michel M Verstraete22:21, 19 June 2006 (UTC)[reply]
All the small insects which have very small wings will end up making the noise while flying, as they have to flap their wings very fast. The frequency of this noise is supposed to be specificto each species. I would say that it is more of a disadvantage to the mosquitoes. Imagine how difficult it would have been for us to track the silent mosquitoes -- Wikicheng05:10, 15 June 2006 (UTC)[reply]
Anything vibrating at a high enough frequency in a medium will produce sound waves in that medium. Birds that hover instead of glide consistently produce a noise as well. --ColourBurst16:58, 15 June 2006 (UTC)[reply]
I've read in more than one source that the noise helps attract male mosquitoes. (Only female mosquitoes bite.) Whether this is the purpose of the buzzing, or it's just a handy side-effect, no one knows.TheSPY14:44, 19 June 2006 (UTC)[reply]
(After edit conflict:) The sun's light is a yellowish colour, so it is not black ("technically" or otherwise,) it is yellowish. -- AJR | Talk23:56, 14 June 2006 (UTC)[reply]
thanks to the latter two contributors for actaully answering my question
Yellowish? I know the sun is depicted as yellow in children's drawings and called yellow when discussing Superman... but isn't the sun's light actually white? If fact, isn't it the definition of white light? Melchoir08:22, 15 June 2006 (UTC)[reply]
Whatever colour the sun is, the spectrum has been messed up by the earths atmosphere, so it isnt the colour it appears. PhilcTECI11:05, 15 June 2006 (UTC)[reply]
Well, Wikipedia seems to contradict itself on this question. From Sun:
"The Sun has a spectral class of G2V. "G2" means that it has a surface temperature of approximately 5,500Ā K, giving it a yellow color, and that its spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines."
"The Sun is not in fact a yellow star, but has essentially the color temperature of a black body of 5780 K; this is a white with no trace of yellow which is sometimes used as a definition for standard white."
Neither of these statements cites a reference. But it seems obvious to me. I mean, a sodium lamp is yellow. If you look at the sun sometime, it's white. Surely there's some scientific meaning of "white" that will allow us to settle the question and reconcile the articles? Melchoir14:33, 15 June 2006 (UTC)[reply]
The sun is black in the sense defined at the start of the article black body: a light shone at the sun would be absorbed. I wondered at first whether the above comment about the sun's emission spectrum being close to black body refered just to the shape of the spectrum or also to the magnitude. It turns out that if you apply the Stefan-Boltzmann law using the values of surface temperature and surface area quoted in the sun article, you get a total luminosity of watts assuming a true black body (zero albedo). The actual value quoted in the article is very near to this, which therefore implies a very low albedo. Arbitrary username18:02, 15 June 2006 (UTC)[reply]
June 15
Composition of Matter
In the Wikipedia entry "matter", matter is defined as everything that is composed of elementary fermions. It is also stated that matter is composed predominantly of atoms.
What else is it composed of?
Portions of atoms which do not form complete atoms?
I don't think "space between things that doesn't contain things" counts as matter. However, the Fermion page notes that electrons, neutrons, and quarks are all fermions. By the definition on the matter page, those particles are all "matter", but are not atoms. DMacks01:24, 15 June 2006 (UTC)[reply]
All everyday matter here on Earth is composed of atoms (and ions, if you say atoms have to be neutral). The Sun, however, is made of hydrogen plasma, which is protons and electrons that aren't associated into atoms. The core of a neutron star is probably not made of protons and electrons at all. āKeenan Pepper01:49, 15 June 2006 (UTC)[reply]
Thank you very much, that answers my question exactly. -Ben
See List of particles#Fermions (half-integer spin) for a list of particles. Of course, most of these are in the form of up and down quarks, combined into protons and neutrons, which are then combined with electrons to make atoms. As noted above, there are a considerable amount on Earth in the form of ions, which are basically atoms with extra or missing electrons (in a sense). Also, in stars, much matter is in the form of plasma, in which the nuclei (protons and neutrons) and electrons are not combined into atoms. As Dar-Ape notes, neutrinos are another fundamental particle, in addition to the up and down quarks and the electrons which probably occurs in large amounts. Then you have the other fermions listed (strange, charm, bottom, and top quarks; muons; taus), which occur much less frequently (the quarks always occur in combinations; they have never been observed in isolation). To that you can add any of the mysterious and hypothetical dark matter. ā Knowledge Seekerą¦¦04:36, 15 June 2006 (UTC)[reply]
The way I always learned it, matter is composed of tiny eensyweensy little atoms surrounded by vast expanses of open space. Each atom is also mostly empty space with a positively miniscule nucleus in the center. So...my answer is empty space makes up most of matter. --M1ss1ontomars2k4(T | C | @)05:08, 16 June 2006 (UTC)[reply]
Thats not really matter is it, thats like calling the airspace in your garden part of you house. And also the quote said predominantly matter, and if you count space as the alternative, it is not predominantly matter it is only an absolutely minescule amount of matter, so clearly, the quote is refering to something else. Its probably some of the more exotic particles. PhilcTECI16:08, 16 June 2006 (UTC)[reply]
Interesting fact - it seems that the majority of the (non-dark) matter in the universe is in a state of plasma. It's the cold, dense atomic matter that makes up our earth that is the exception; we're just an unlikely island of weird fundamental physical interactions in a plasma universe.--Bmk03:51, 17 June 2006 (UTC)[reply]
Java Image Editing
There's still some disagreement over which desk should get computer problems, so I'm going to go with this one and hope no one minds. I had a great snippet of Java code (I found it on the Internet somewhere) that could take bitmaps in, convert them to two-dimensional arrays, change the numbers however I wanted, and save the result to a bitmap. Unfortunately, the hard drive it was on died and I don't remember the details. Does anyone know how that works? Black Carrot02:00, 15 June 2006 (UTC)[reply]
The BMP format in its common uncompressed variant is entirely trivial to parse; see that page and/or its external links for the file's format. In Java you'd just make a FileInputStream (or some other type of input stream) and read first the image size. Allocate the appropriate arrays, then read the image data into the arrays. Obviously you can do whatever you want with the arrays, and it's just as easy to write them back into a file with the appropriate header information. I've done exactly this, although (as it happens) with C++ instead of Java. Or were you asking for help in finding or reconstructing this code? --Tardis04:28, 15 June 2006 (UTC)[reply]
I never cease to be amazed at the infinite versatility of the English language. One person's "great snippet" is another person's "trivially easy". Pretend I'm dumb as a post. (I'm not, but I am profoundly uneducated, considering I was in CS for two and/or three years.) I don't know much about reading and writing files. Could you show me how to do that? Once I can get it into and out of array form, I know enough to make the pictures I want. Black Carrot16:50, 15 June 2006 (UTC)[reply]
The easiest way in Java is probably using the ImageIcon class to load the image (this will work for jpg, png, gif & bmp files in most implementations), then create a BufferedImage in the format you want to use (e.g. 8 bit-per-channel), and draw the loaded image onto the BufferedImage using drawImage. Then you can use getRGB to get and manipulate the arrays as you want, then use setRGB to update it. To write it out again, use ImageIO.write() to save in the format you want. Very rough code:
ImageIcon icon = new ImageIcon(filename);
Image i = icon.getImage();
int w = i.getWidth(null), h = i.getHeight(null);
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.drawImage(i, 0, 0, null);
int [] data = new int[w*h];
bi.getRGB(0,0,w,h, data, 0, w);
// data now contains pixel data in (A)RGB format
// do stuff to data array
bi.setRGB(0,0,w,h, data, 0, w);
ImageIO.write(bi,"png", new File(newfilename)); // write in PNG format
(I asked this on the talk page of the corresponding article, thought maybe I would try here as well) As far as I know there are no fireflies in warm dry areas (like on the west coast of the united states). Is this because fireflies prefer more humid climates or is temperature a factor? Would it make sense for an insect to overwinter in a warmer climate at all? --69.249.30.10902:21, 15 June 2006 (UTC)[reply]
Well, you may be onto something regarding the dryness or humidity of the climate. But I can say for a fact that there are fireflies in Central Africa (Southeastern Cameroon, to be precise), and that's a pretty damn hot place. ā BrianSmithson18:11, 16 June 2006 (UTC)[reply]
Which taste? Water will taste tasty if the fever is accompianied by a stuffed-up nose because the scent of the mucus will make the water taste like snot. If you mean the taste of the saliva in the mouth, I don't know, it never seemed bitter to me. Emmett503:35, 15 June 2006 (UTC)[reply]
I am not sure if food tastes bitter but I have experienced that it is kind of tasteless, probably because our tongue wil be covered by a kind of white layer of something (I don't know what it is) when you have fever -- Wikicheng05:20, 15 June 2006 (UTC)[reply]
The taste page might be of use: its intro mentions the importance of smell, so consider stuffy noseāreduced olefactionāfoods taste blander. Later on, the page mentions body temperature as having an effect, but doesn't seem to discuss the effect in any detail:( DMacks06:21, 15 June 2006 (UTC)[reply]
You shouldn't eat people who have fever. Not only will they taste bitter but if not properly cooked you may contract their fever. AllanHainey10:19, 16 June 2006 (UTC)[reply]
Can anyone recommend a (relatively reliable) free online IQ test? If I'm looking to take the test for real, I'd like to have some indication on how well I'm likely to do, and though I've taken a bunch of them for kicks (such as [6] and a few of the ones on [7]) and the scores have been relatively consistant, since none of them are real and most of them are quite short, I can't be really sure if the scores I'm getting are realistic at all! Is there anything out there with a little bit more authority? Ā freshofftheufoĪĪÄæŠĀ 04:12, 15 June 2006 (UTC)[reply]
Personally, I don't think that there are any reliable ones. With the quick ones I used to do online, I'd get scores of >160, which I don't think is accurate at all. My guess is that they inflate the scores to make you feel good about taking them. ā Asbestos | Talk (RFC)14:15, 15 June 2006 (UTC)[reply]
You have to keep in mind, an actual IQ test is a very sensitive tool, designed by professional psychologists for the use of professional psychologists. To be valid, it must conform to the many strict rules guiding scientific research. Tests over the internet, even home tests in hardcopy workbooks, cannot really do that. However, to get a ballpark figure, the free Mensa excercise is probably your best bet. Be careful to follow the rules, though, and don't go over the time limit. BTW, what was your score on the online tests? Black Carrot15:58, 15 June 2006 (UTC)[reply]
Those online IQ tests tend to be rather rubbish; one gave me a score of 180, which is in the region of the top 0.0001%. But since it said the "average" score was 139 (on a normal IQ test, it should be 100), I'd take it with a pinch of salt. smurrayinchester(User), (Talk)20:45, 15 June 2006 (UTC)[reply]
I've noticed that most online IQ tests tend to be coupled with ridiculous amounts of advertising, so my guess would have to be that they're trying to flatter peoples egos, so they'll be more likely to buy stuff, as a general rule (:205.188.116.7421:14, 15 June 2006 (UTC)[reply]
Well, I would expect that those who would want to take IQ tests online are those who are more likely to feel that they will score highly on them, and so more likely to score highly, period.... 04:23, 16 June 2006 (UTC)
If you really want to know your IQ, you should see a...psychiatrist? psychologist? one of those psy people, for sure. That's what I did, but I took the WISC III in 3rd grade and scored too close to the top of the scale to get a good reading. --M1ss1ontomars2k4(T | C | @)05:06, 16 June 2006 (UTC)[reply]
Carbon Dioxide
Carbon dioxide gas and water vapor both absorb IR radiation. Do they also absorb visible radiation?
I don't know much about the subject, but I think that since humans can see dark smoke (carbon dioxide), it can't be letting all visible light pass through it. Some of it is getting absorbed, which is why the smoke looks dark. I assume that the explanation is similar for water vapour. -- Daverocks (talk) 13:13, 15 June 2006 (UTC)[reply]
Dark Smoke is not Carbon Dioxide, unless you know something I do not. Dark Smoke is unburned particles from a fire.
Why is it obviously written by a Canadian? English people spell colourlesscolourless and we spelt it that way first. If anything should be given a (sic) it should be the American way of spelling it colorless. I'm sorry about that, but I really don't like American spellings, nor pronunciation. Anyway, back on the topic, I once saw a demonstration where carbon dioxide was poured out of a container and although you could not see the gas itself, you could see a very distinct shadow. This seems to indicate that it does absorb a small amount of visible light, although I am most probably wrong. --80.229.152.24619:06, 15 June 2006 (UTC)[reply]
It's not a "shadow" in the conventional meaning (something blocking some light), but rather an effect of carbon dioxide having a different index of refraction than air. If an even level of light room light passes through side-by-side regions of high-CO2 and low-CO2, one will diffract the light differently than the other. That will make the image cast have different levels at the interfaces due to one region of light being shifted relative to the other. This is similar to how you see wavy effects if you look at an object across the top of a hot surface. DMacks20:06, 15 June 2006 (UTC)[reply]
Dark smoke is unoxidized carbon, which iscreted when something is burnde in an oxygen lacking environment allong with carbon monoxide. This does not mean in oxygen low air, as any fire with a yellow flame is oxygen lacking. Hence if air is correctly introduced beofre burning, you get a blue flame, like on gas cookers. PhilcTECI14:36, 15 June 2006 (UTC)[reply]
Carbon dioxide and water vapor are both transparent at visible wavelengths. Automobile exhaust contains both compounds; notice how the exhaust is invisible under normal conditions. (If your car is burning too much fuel/not getting enough air, the exhaust turns black; those are particles of unburnt fuel: soot, the same sort of stuff that colours smoke. In cold weather, you can see a white cloud; this is because the cold air condenses some of the water vapour into liquid water droplets that scatter light like a little cloud.) TenOfAllTrades(talk) 13:46, 15 June 2006 (UTC)[reply]
I'm pretty sure CO2 does not absorb visible radiation (definition of colorless). But water vapor does absorb some, since it's simply water, and water absorbs visible wavelengths of light, particularly red. --M1ss1ontomars2k4(T | C | @)05:05, 16 June 2006 (UTC)[reply]
Question about Marine and Ship Designing.
I would like to know something about what subjects and areas are invloved in Marine and Ship designing. If possible, would like to have some website links which explain the various concepts involved in it.
Let's assume there's a nuclear free-for-all in the northern hemisphere. China vs. USA vs. Russia vs. France vs. Britian... Israel vs. the rest of the middle East... India vs. Pakistan... basically every nuke that could fly, does.
Would this wipe out all life on the planet, or would the southern hemisphere be largely unaffected (apart from the massive economic collapse caused by losing the northern hemisphere)?
And speaking of which, would life up there be COMPLETELY gone? Because according to Threads, some people would survive, they'd just be living in an incredibly bleak and pointless world.
The southern hemisphere would be greatly affected -- the atmospheric patterns of the hemispheres are mostly isolated but not completely so (note that large volcanic eruptions have effected global temperature shifts). Even if fallout settled out first, nuclear winter would still wreck things fairly readily. As for complete annihilation, there would probably be survivors, at least initially. Brinkley's The Last Ship posits that the real problem would be one of repopulation. ā Lomn | Talk17:08, 15 June 2006 (UTC)[reply]
The Nuclear Winter scenario was popular with Carl Sagan, but when the numbers were crunched, it was discoveredthe effect would not be as catastrophic as he predicted. Even if he were correct, there are organisms which would manage to survive.
I doubt that nuclear war could ever destroy *all* life on earth - insects and bacteria can be very tough and there are plenty of organisms in the depths of the oceans that would probably escape the worst of it. Mass extinction of mammal and bird species on land would probably be a given in the nuclear winter that followed but even then, I doubt that *everything* would be wiped out. Life has a funny way of 'getting on with things'. --Kurt Shaped Box23:00, 15 June 2006 (UTC)[reply]
Life survived, amongst other things, the Chicxulub Crater impact. Nuclear war is small beer by comparison, unless we were silly enough to use the cobalt bomb. Even if we were to use them en masse and wipe ourselves out, microbes and insects would still probably survive. --Robert Merkel23:42, 15 June 2006 (UTC)[reply]
Sorry, maybe I wasn't completely clear in my original question: I meant would any human life survive - after all, we're the only ones that matterĀ ;). Basically, would the scenario described in John Wyndham's The Outward Urge (in which the southern hemisphere remains habitable after a nuclear war) at all plausible? (and sorry I didn't log in the first ime to ask) Battle Ape04:44, 16 June 2006 (UTC)[reply]
In response to (and friendly rivalry with) JackofOz, I have to point out that one of Wyndham's other novels, "The Chrysalids" details remnants of a post-nuclear war North American society. In that, the one surviving society - and even then surviving with a few major alterations - is in the far south and called new Sea Land, "only spelt with a Z". Grutness...wha?10:26, 16 June 2006 (UTC)[reply]
I disagree that "we're the only ones that matter" - just imagine if some bomb was invented that killed all other life & left humans, humans wouldn't last much longer before succumbing to starvation, disease, depression and other psychological problems (or you could wait 50 years and see the results of the 6th mass extinction to get an idea). On whether the southern hemisphere would be habitable, it would certainly be able to support a lot less life than it does now given the levels of radiation in the atmosphere, just look at the amount anf effects of the radiation released by Chernobyl, it's effects are still being felt in Wales (some sheep can't be sold as radiation is too high). AllanHainey10:43, 16 June 2006 (UTC)[reply]
Orgasm
I always have ejaculation and orgasm while masturbating but never while fucking a woman, none of these two things. What's the matter? Johny Bill, 19:30, 15 June 2006 (UTC)[reply]
Perhaps you aren't "concentrating" on what's avaliable at the moment, but while masturbating, are free to "concetrate" on whatever you please. There is a such thing as masturbating too much to a point where you become immune intercourse because it cannot satisfy you the same way your fantasies do. This may not be true in your case though. If you feel that your masturbation tendancies are not abnormal, then the problem could be something else. Do you have an intimate relationship with this "woman"? If not, do you experience this impotence with other women? Have you considered drugs such as Viagra, Cialis, or Levitra? --Chris22:14, 15 June 2006 (UTC)[reply]
It could simply be the case that you're so used to 'flogging the dolphin' really hard and fast that a woman's vagina simply doesn't provide the same level of stimulation. Try cutting back on the wanking for a few weeks and see if things get any better for you... --Kurt Shaped Box22:37, 15 June 2006 (UTC)[reply]
Read this article from Dan Savage about training your penis to get off on the "death grip." Here's the question that reminds me of your problem:
Remember how one time (or maybe two) you warned a guy (while remaining masturbation-positive) not to condition his body to come only in response to a particular kind of stimulation? I believe ('cause I looked 'em up) your exact words were, "If you hold your cock in a death grip every time, you may find it difficult to climax as the result of other, more subtle sensations."
Well, unfortunately, I read your excellent advice too late. About 30 years too late. So now, while women think it's cool that I can "stay hard all night," they eventually start to get a complex about the fact that, though they're having orgasms galore, they can't seem to make me come. It's not them, of course. It's the years and years and years of death-grip masturbation.
Help me, Dan. What can I do to climax in response to "more subtle sensations"?
While Viagra might help with getting an erection, it won't help you come. I have a similar problem, but getting the lady to close her legs helps by increasing the friction, as do ribbed condoms. --83.245.18.3407:34, 16 June 2006 (UTC)[reply]
Speed of light changing?
According to Einsteinās general and special theories of relativity, this states that the speed of light cannot change.
However I am confused by this:
The way I have always understood the theories of relativity is that time slows down to keep the speed of light constant relative to your own velocity. However if this is the case then moving at any speed will cause the speed of light to change relative to you, for example, the speed of light is moving at 2.998e10^8 but if we are moving at a velocity of 30 ms^-1 then the speed of light traveling towards you would be: 2.998e10^8ms^-1 + 30ms^-1. I knew that the speed of light could never change so I therefore thought that time would slow down to keep the speed of light constant but if this is the case then time would slow down to the point at which you would not move, because if you move at any speed then c, would change relative to you??
I am kind of an amateur scientist, but here is what I understand.
1) When light passes through matter, like glass, it slows down, so the speed of light CAN change, irrespecive of relativistic effects.
2) When the velicity of an object increases, so does it's mass, this has the effect of slowing down observations, and this slowing is not noticed. This is because the reactions act more slowly on massive objects.-12.10.127.58Ā (talkĀ Ā·contribs) 20:12, 15 June 2006
actually no, the speed of light doesn't change in a refracive medium, rather, the thing that makes a medium refractive in the first place is it's ability to absorb and emit photons of a given wavelength, the excitation and emission process takes a finite amount of time, rinse and repeat a few million times, and the net amount of time for photons of a given type to pass through that medium is increased, without altering the fundamental velocity of light. The only thing special about vacuum is there's nothing there to emit photons, so c is always c--205.188.116.7420:30, 15 June 2006 (UTC)[reply]
Let's talk about the speed of light in vacuum. As others have pointed out, the speed of light in a material can be less. Where the original question goes wrong is the assumption that you can still use the relative velocity formula of just adding two velocities when you get near to the speed of light. Actually what you need to do is start with the fact that the speed of light doesn't change, as this is the experimental observation (see Michelson Morley experiment). Then you can do various thought experiments about what the consequences of this will be. And purely through a series of carefully constructed thought experiments, you can end up deriving an expression for how to combine velocities. Specifically, if the two velocities are u and v, you get:
where c is the speed of light.
It turns out that if the two velocities are both much less than the speed of light, then it's very close to just adding up the velocities (as you'd expect). But if one of the velocities is the speed of light, then the combined velocity is still the speed of light. Arbitrary username21:22, 15 June 2006 (UTC)[reply]
I'm not exactly sure what you are asking, but if you can move at the speed of light, time does indeed dilate to infinity. In other words, it will appear as if the clocks of other people has totally stopped. Similarly so, length contraction occurs, and the universe would appear to contract to a point. This suggests that, in your frame of reference, it takes no time at all to get anywhere. -postglock03:54, 16 June 2006 (UTC)[reply]
Back to the original problem (changing speed of light), I've always interpreted it as being a wave in this case, and sound always travels at the same speed, so I never had any problems with this. Most likely I'm missing something, as I'm significantly better in chem and bio than in physics. --M1ss1ontomars2k4(T | C | @)05:02, 16 June 2006 (UTC)[reply]
sound always travels at the same speed Is that so?
Regardless, light and sound have so little in common that all but the most basic of analogues are misguided. Skip that. The problem with your question is that the speeds you reference are in units of distance AND time. Change the rate of time, and the numbers will have to change. It is hard to grasp without much study, but just trust Einstein when he says that you will never catch light in a vacuum going any speed besides C.
There's nothing in relativity that says the speed of light can't change. A popular idea in cosmology is that fundamental constants like the speed of light may be changing, though very slowly. The weak anthropic principle is the idea that the constants of nature vary from place to place in the universe, and we exist where we do BECAUSE the physical constants in this area are favorable for our type of life. Nifty, eh?
And to the orignal asker of the question, I would strongly recommend a special relativity course; it's the best way to understand this stuff. And it will blow your mind! Wheeeeee --Bmk04:41, 17 June 2006 (UTC)[reply]
worms - destined for greatness?
hi,
i was told by my primary school teacher that if you cut a normal, garden worm in half, the two halves will grow back into two new, fully functioning worms. my question is, is there a finite amount of times you can cut up a worm for this still to be true? if i cut a 10cm worm into 100, 1mm pieces, would i get 100 new worms or would the 100 pieces be too small to regrow and hence die? thanks! 87.194.20.25319:49, 15 June 2006 (UTC)[reply]
If you cut a worm in half, both ends will continue to move for a short time, but both will die. If you cut it in a certain place, theres is a tiny chance that one end will survive. Dont believe primary school teachers on complex science. PhilcTECI20:18, 15 June 2006 (UTC)[reply]
There is a worm (not an earthworm, though) that you can cut in half, and the halves will regrow, given time, into wholes. I think it might be the flatworm. The article agrees, at the end of the Body Functions section. Black Carrot15:07, 17 June 2006 (UTC)[reply]
Just in case the article wasn't clear enough, the cut has to be lengthwise, across along the body from "head" to "tail", not separating the "head" from the "tail".--Tachikoma15:31, 17 June 2006 (UTC)[reply]
Whats the best diet/excercise for maximum muscle build and fat loss in the shortest length of time (ie a few weeks) even if you can spend everyday working solidly. I was thinking maybe anaerobic excercises, but I dunno. And also what are some examples of them as I don't know any anaerobic excercises, if that is the right answer. Thanks dudes. Have an awesome summer everyone, or winter you unlucky southernersĀ :-P. 195.93.21.819:55, 15 June 2006 (UTC)[reply]
Anaerobic excercises include activities such as weight lifting. These are best for muscle building, while aerobic exercises (those that a "fit" person can maintain for a long time) are probably better for fat loss because you can burn a lot of calories with sustained activity. A combination of the two is probably best for overall fitness. Add some stretches for flexibility. --Ginkgo100talk Ā· contribs20:54, 15 June 2006 (UTC)[reply]
Outer Layer of Salmon Meat
I just baked a salmon before scaling it. So after cooking there is a thick section of pink coloured meat, on top of which is a thin layer of brown/pink meat which is easily scraped off seperate from the pink meat. On top of the brown/pink meat was the scales. The question is: What is that brown stuff? And more importantly: should I eat it? Thanks --Tacobake
You can eat the skin and all the meat, both the pink and the brown. In fact, in Japan salmon skin is considered a delicacy. Just don't eat the scales. The brown meat tastes like the pink meat to me, and is probably a different kind of muscle tissue. --Ginkgo100talk Ā· contribs20:51, 15 June 2006 (UTC)[reply]
Hello. I am running Windows XP and I am having a desktop problem. There appears to be unwanted shadows behind the incons on my desktop (but here only). If the color of the background is white, and the color of the desktop is (right clicking the Desktop > Appearnce > Advanced), say, black, then the shawdows behind the icons on the desktop are black. The problem is that there is no option to not select "blank". When I create a new account on the computer, the solution is solve; but I don't want to keep two accounts. Do you know what the problem is? I can supply a picture if you want to email me, but I don't want to upload it to Wikipedia to illustrate a point when it won't be used in any articles. Thanks a lot. Kilo-Lima|(talk)21:12, 15 June 2006 (UTC)[reply]
Right click on "My Computer" on your desktop and select properties. Click on "Advanced" and under "Performance" click on "Settings." Scroll to the near bottom of the list under "Visual Effects" and you'll see "Use drop shaows for icon labels on the desktop." Remove the check next to this box. -Quasipalm00:50, 16 June 2006 (UTC)[reply]
This is unchecked, but the problem still exists. I also checked the preferences on the other account that I have created, and the only thing that is un-checked is "Smooth text on explorer windows" or something similar to that matter. Thanks. Kilo-Lima|(talk)14:57, 16 June 2006 (UTC)[reply]
Lobsters
The earthworm question above have prompted me to ask this question: Why do lobsters (and other crustaceans) not die when they are dismembered, halved, or removed from water? How do they die in a pot: do they simply cook from the outside-in until there is not enough living flesh to sustain its life? Do they feel pain? --Chris22:01, 15 June 2006 (UTC)[reply]
Feeling pain is notoriously heard to determine, even impossible. The nerve system of a lobster most certainly registers bodily damage and they are most certainly physically aware (e.g. their body is prompting them to make appropriate reactions in order to remove the cause of pain) that they are being dismembered or boiled, whether this constitutes pain or simply a reaction to a stimulus is highly debated. Adversely, some people argue that pain doesn't exist at all, evidenced by the amazing abilities of some people to do certain (disgusting) things to their bodies without feeling any need to counteract. But... that's another issue. Ā freshofftheufoĪĪÄæŠĀ 01:48, 16 June 2006 (UTC)[reply]
There are some links at the Lobster Liberation Front (i mean, really!) page that may inform you:
Whole Foods has just announed that they will no longer sell live seafood fish. It makes one wonder how they think their suppliers will produce the seafood body parts which they will continue to sell. User:Zoe|(talk)16:08, 16 June 2006 (UTC)[reply]
Did they say "all live seafood"? I thought it was just lobsters and softshell crabs. Anyway, the issue is the nasty and long conditions in between capture and killing; I imagine the ones selling parts catch 'em and kill 'em (and probably freeze 'em) real quickly? --jpgordonāāāā02:42, 17 June 2006 (UTC)[reply]
Jogging at the speed of sound
I just read this question in a humorous context, but seriously what would be the answer to it? "If a jogger ran at [or above] the speed of sound, could he still hear his Walkman?" --Lph22:17, 15 June 2006 (UTC)[reply]
Probably not, but simply because the roar of the wind rushing by would drown it out. The air between his ears and his headphones would be moving along with him. āKeenan Pepper22:29, 15 June 2006 (UTC)[reply]
Assuming perfect conditions; e.g. he is jogging at the speed of sound and the wind is also blowing in the same direction at the speed of sound, then I believe the answer would be yes, he could hear his walkman. The speed of sound isn't a speed limit, and since the speakers emitting the sound are also moving at the speed of sound many of the sound waves would end up vibrating through the (small space of) air at a speed well above the speed of sound, and many would be well below it. I think. Ā freshofftheufoĪĪÄæŠĀ 23:42, 15 June 2006 (UTC)[reply]
Can you talk to other passengers in a jet? Of course. If the air in between you is moving with you, and all other sound is muted (not the case with headphones), you'll hear just fine. Black Carrot23:43, 15 June 2006 (UTC)[reply]
Well the air between the headphone and his ear is probably trapped and therefore moving with him, so he should still be able to hear the walkman. (And even if not, there may still be enough sound conduction through solids to enable this.) A related question is if he was out running with a friend (i.e. the air between them is not trapped), would he be able to hear his friend? At exactly the speed of sound, she would have to be at least a little in front of him. (She could also be off to the side, but the sound energy she emits is anisotropic and he will receive comparatively more of the sound from her if she is more directly in front of him.) At higher speeds, she will have to be that much closer to being directly in front.
You could similarly consider the problem in terms of standing still in a wind tunnel. Of course not only is actually runnig at mach number 1 in still air ridiculous, so is even trying to stand up in a wind tunnel at that air speed. The wind force goes as the square of the air speed, and given the range of wind speeds defined as being a gale (see that page), the wind force would be several hundred times stronger than when standing in a gale. Arbitrary username07:58, 16 June 2006 (UTC)[reply]
A more rational question is "do passengers on a supersonic jet hear engine noise" and the answer is, only if they are in the Mach cone behind the engine. moink08:31, 16 June 2006 (UTC)[reply]
New question
All this speed of sound talk got me thinking: if I run at twice the speed of sound, and have a large speaker playing a song real loud for several seconds. Then about 50m after that I come to a full stop, will I hear the song backwards? VdSV9ā¢ā«14:40, 19 June 2006 (UTC)[reply]
The end of the world...
Following on from the 'nuclear apocalypse' thread, I find myself wondering about humans literally causing 'the end of the world'. While we are certainly capable of causing the extinction of our own (and other) species, be it via nuclear war, a manmade virus, poisoning the air and seas, destruction of the ozone layer, etc. - is there anything that humans could do/cause that would literally 'destroy the world' (i.e. result in the complete anihilation of the Earth)? I can't think of anything offhand - even if all the nuclear weapons in the world were set off in a huge global pissing war, the net result to the planet would only be a few craters and scorch marks on the surface, right? Would I be right in thinking that the only kind of event capable of destroying the planet itself would be one of extraterrestrial origin (e.g. a gigantic asteroid/planetoid collison, the expansion of the sun into as red giant, etc.)? --Kurt Shaped Box23:16, 15 June 2006 (UTC)[reply]
Yep. About the only thing I can think of that could destroy the entire planet would be an unlucky collision with a stray interstellar planet, or a near miss close enough to significantly change the Earth's orbit. A sufficiently massive intruder could also destroy the Earth indirectly, by perturbing the solar system enough to cause another planet to collide with the Earth ā but if the intruder was big enough to retain significant primordial heat and close enough to be a short-term threat, there's a good chance we would've seen it already. āIlmari Karonen (talk) 23:34, 15 June 2006 (UTC)[reply]
I've heard of scientists making tiny, unstable (meaning they disappear immediately) black holes in a lab. I think they're so small they instantly radiate out their entire mass, or something like that. Could they make a bigger one that would eventually swallow the earth? Black Carrot23:42, 15 June 2006 (UTC)[reply]
Googleimages thinks it's a plain western baby gull (searched for ... baby gull). Do you need some western latin nameĀ ? [She gulps sea gull on the sea. Whore!] --DLL19:31, 16 June 2006 (UTC)[reply]
The photo is from Norway, so it almost certainly isn't a Western gull. It could, however, be just about any of the gulls found in Norway, which include the Common gull, the Herring gull, the Lesser and Greater black-backed gulls, the Glaucous gull and the Black-headed gull. Based on the photos I could find on the web, Black-headed gull chicks don't seem to have an orange beak tip, so we can probably rule that one out ā but the others all do, and look pretty much identical in all other respects too. āIlmari Karonen (talk) 15:24, 18 June 2006 (UTC)[reply]
How likely is a person to develop tremors from the poisons in a flea collar? Are these tremors permanent?
If you are experiencing tremors, particularly if you think you have been exposed to a poison, go and see a doctor quickly. Skittle08:58, 16 June 2006 (UTC)[reply]
i was wondering if you could help me describe three functions of arthropod's appendages?
-tracy
Well, walking should be obvious. I think spiders, at least, mate using them (if the pedipalp is an appendage, and if not, the male holds the female with undoubted appendages during mating). And some species use them to make noise. (Do any have sensory organs on them? that might be another bonus use). - Nunh-huh04:14, 16 June 2006 (UTC)[reply]
i was told that if you are driving at 20mph and do a sudden stop that a person in the back set (who doesnt have a seat belt on) will hit the back of your seat at 40mph. is this true? i think it sounds fishy
what i thought but what is the term for that effect
Inertia is the term that explains the motion: the person keeps going in the same direction and with the same speed until something stops him. Organ donor is the term that may describe the result. DMacks04:10, 16 June 2006 (UTC)[reply]
Actually, if the person's knees hit the seat first, their head will impact the seat at a speed that could be greater than 20 mph, due to rotation - but probably not at 40 mph, by my guesstimation. --AySz88\^-^04:13, 16 June 2006 (UTC)[reply]
If two cars travelling towards each other at 20 mph collide head-on, then the impact on the persons inside each car would be 40 mph -- Wikicheng05:12, 16 June 2006 (UTC)[reply]
? Maybe if my car is very small, going at 20 mph and collides head-on with a lorry going at 20 mph. Then I'd be going at nearly 40 mph relative to my car, but the lorry driver would be practically stationary relative to his cab. The cars would be going at 40 mph relative to each other. The thing that really got me to strap in, apart from reflex, was the ad with the teenage son in the back, behind his mother. Car crashes, son is thrown forwards against mother's seat, crushes mother to death on the steering wheel, then sits down relatively unharmed. *shudder* I'm guessing his mass is important here, as well as the relative speeds and deceleration. Skittle08:56, 16 June 2006 (UTC)[reply]
There was a question here a few weeks ago where we determined that if two identical cars going the same speed ran into each other, it would be identical to each running into a perfect wall. Black Carrot14:52, 17 June 2006 (UTC)[reply]
That doesn't make sense to me. If two identical cars were each traveling 20 kilometers per hour and they hit each other, at the time of impact they would both be traveling at 40 kilometers per hour relative to the other. Therefore the impact should have been the same as each running into a perfect wall at twice the speed. --M1ss1ontomars2k4(T | C | @)00:32, 18 June 2006 (UTC)[reply]
No because the other car isn't a perfect wall (i'm presuming this is defined as something that will not move or deform under any impact).
When the car hits the perfect wall all its kinetic energy must be dissipated into the car.
When the cars hit each other the total kinetic energy is doubled but it is also split equally between the cars (assuming the cars are identical and the collision perfectly head on) so the energy that must be absorbed by each car is the same. Plugwash23:07, 19 June 2006 (UTC)[reply]
Radiation therapy and Brachytherapy
When did doctors start using radiation therapy and brachytherapy to treat cancer?
It sounds weird that any 'technology' question goes here, because my problem has little to do with science. I just finished making Image:Ladakh1.svg. It shows if you click to see the full resolution version, but doesn't show on the article, or even the image page. Any solution to this? deeptrivia (talk) 06:23, 16 June 2006 (UTC)[reply]
Why do airplanes draw their wheels in while flying? My guess is: To reduce drag due to air friction. Any other reasons? -- Wikicheng06:59, 16 June 2006 (UTC)[reply]
Air friction would also affect their handling characteristics. Light aircraft, of course, don't withdraw their wheels, but they are relatively small ones.--Shantavira07:54, 16 June 2006 (UTC)[reply]
Yes. Reducing the air friction has many benefits. So am I right in concluding that reducing air friction is the only reason for withdrawing the wheelsĀ ? -- Wikicheng09:05, 16 June 2006 (UTC)[reply]
Well, see above. It would reduce noise too, for the same reason. I guess you could also say it looks a lot neater, and reduces wear on the landing gear which would get very dirty if it continued to dangle, and prevents birds getting bashed by the gear....--83.245.18.3410:12, 16 June 2006 (UTC)[reply]
Also, think about it. You've got a plane going at 400mph with some relatively thin bits of complex machinery dangling from underneath. Machinery that you'd really really like to have in full working order when it comes time to land. Which is better, to keep them exposed to wind going by at a relative velocity of 400mph (i.e., three times Hurricane Katrina's velocity) or safely tucked up in a recess under the plane? Grutness...wha?10:34, 16 June 2006 (UTC)[reply]
Hmmm... okay. I am convinced. It is not for nothing that they spend so much on designing the landing gearsĀ :-) -- Wikicheng11:03, 16 June 2006 (UTC)[reply]
hi,
for someone (me) with acne-prone skin, is electric shaving better for my skin than wet shaving or is there no difference? i'm 21 (although 22 on tuesday-yikes!) and (if it was in doubt) male, if that helps.... if anyone is capable of giving a definitive answer it would be really appreciated by my rapidly-ageing self..thanks! 87.194.20.25310:06, 16 June 2006 (UTC)[reply]
I read that wet shaving is better for exfoliation. If your acne is bothering you, maybe you should speak to your GP. I'm not sure, but I recon 22 is getting a bit old to still be affected by acne and doctors have got all kinds of crazy treatments that'll clear that stuff right up. --Username132 (talk) 21:05, 18 June 2006 (UTC)[reply]
By wet shaving it sounds like you're referring to shaving in the shower, but that's not necessary. It is necessary to moisten the skin of your face in order to remove dirt that could obstruct the blade and to clear/open your pores to allow the hairs move when they are cut, which prevents ingrowth. It's a good idea to shave right after you shower, but 30 seconds of water-heavy rinsing should have the same results.
Secondly, probably doubly important due to the fact that you are acne-prone, do not cut your facial hair too short. Single and double razors tend to cut the hair too short for some people and end up irritating the skin around the hair follicles, and electronic razors are recommended because they tend to leave a reasonable amount of hair at the root, preventing irritation and ingrowth. Hope this helps. Ā freshofftheufoĪĪÄæŠĀ 05:55, 19 June 2006 (UTC)[reply]
Audio files on websites
Sometimes there is audio or video on websites that refuses to play on my computer. All the stuff on putfile.com for example. It shows the media player thing, and says Ready but nothing happens when I press play. Any ideas? 86.130.171.1011:06, 16 June 2006 (UTC)[reply]
Babbage's analytical engine, if he had managed to build it, would have run programs stored on linked strings of punched cards like those used to control the Jacquard loom. The same technology was used to create the book music that was played by fairground organs. Same principle as paper tape, but more rugged. Gandalf6116:09, 16 June 2006 (UTC)[reply]
The first electronic computers (i don't belive there were ever any fully successfull mechanical ones) were "programmed" by moving wires arround, then came switch based entry (with machines like the baby) probablly followed by electromechanican and then magnetic storage. All early programs were written directly in machine code (assemblers and compilers came much later) .
What happens if you fall into a aeration tank at a sewage treatment plant?
WHat happens if you fall into a aeration tank at a sewage treatment plant?
Not much? Not much? Would you care to try it? The questioner no doubt suspects that air being blown up through the sewage (I'm guessing that's how they work) will reduce the density so that the idiot will sink. I suspect this too. Googling around this suggests that lots of people have drowned in sewage treatment tanks. So "you might die" is a not unreasonable answer to this intriguing question. From the onlooker's point of view, "not much" trace left, or "not much" to see, might be fair comment.--Shantavira19:08, 18 June 2006 (UTC)[reply]
The article title seems reasonable enough, but the contents of this newly created article seem highly dubious to me.
However, I know enough about Science to fill a reasonably small matchbox, so I wondered if some of you friendly boffins might like to take a look. --Dweller12:36, 16 June 2006 (UTC)[reply]
(Incidentally, the boffin page seems over-the-top on the disparaging/admiring spectrum, don't you think?)
Normally, NaBH4 is used to reduce an aldehyde or ketone to an alcohol (e.g. H3CCOCH3 -> H3CC(OH)CH3. However, normally hydrogenation with a nickel catalyst works fine to add hydrogen to a compound. My question is, why is that not used here? Is it because hydrogenation with nickel would remove the oxygen altogether, leaving (in this example) propane? --83.147.171.1213:23, 16 June 2006 (UTC)[reply]
As far as I know, hydrogenation is only used to convert alkenes (and sometimes alkynes) into alkanes. On the other hand, a Google search for "acetone hydrogenation" yields some interesting results. BTW, you must have made a typo in your formulas because you have dimethyl ether and then an impossible compound. Acetone and isopropyl alcohol both have three carbons. āKeenan Pepper01:09, 17 June 2006 (UTC)[reply]
Oops, sorry, left out a C in each case. Now corrected above. As for hydrogenation being used only for alkenes, I know I've seen it suggested for use with nitrates (to get to an amine), along with converting an acyl group to an alkyl group. --83.147.171.1211:12, 17 June 2006 (UTC)[reply]
How does the thickness of the metal affect the force needed to compress a spring?
Something of a random question (one that came to me as I fell asleep a couple of nights ago and which has no practical application at all for me), but...
How does the diameter of the metal used to make a spring affect the spring's resistance? Even with my extremely limited knowledge of physics I know it's unlikely to be a 1:1 correlation, where a double thickness wire yields a double strength spring. But is there a simple formula for it?
Thanks for reading: this is my first post on Wikipedia!
Ben Wells, UK
Congratulations! Yes, indeed - you can edit almost any page on Wikipedia. Check out Wikipedia:Welcome, Newcomers - there might be some useful links there. As for the spring question, I suspect that there really is a simple formula - so long as you are operating in the linear regime of things - that is to say, you're not trying to stretch or compress the spring beyond it's typical limits. The stiffness of a spring is governed by its spring constant...does anything in the article help? --HappyCamper15:07, 16 June 2006 (UTC)[reply]
Doesnt hookes law deal with the correlation between forc and compression, not thickness and force recquired to compress. PhilcTECI15:54, 16 June 2006 (UTC)[reply]
Assuming the shear stress doesn't change between thicknesses for a given compression, the force should be proportional to the cross-sectional area, or the square of the thickness. Melchoir16:16, 16 June 2006 (UTC)[reply]
As I recall, bending stiffness of a piece of metal increases as the fourth power of thickness. For a cantilever or leaf spring, doubling the thickness will increase the force by a factor of 16. Other types of spring are more complicated to figure out. --Serie18:45, 16 June 2006 (UTC)[reply]
Thanks. I think Melchoir's explanation is probably the easiest for my layman's head to get itself round!
Weather Balloons
I am confused how or even if possible would you gget a craft lifted by weather balloons or any baloon to return to Earth without the balloons reaching a high altitude and exploding? Or how can you get the craft to return to Earth before that dreadful fate? āĀ Preceding unsigned comment added by 68.120.85.145 (talk ā¢ contribs)
Helium is the second element in the periodic table of elements. Atoms of helium (there are no molecules: this is an inert gas) are relatively tiny, and it is hard to design and manufacture membranes that are absolutely impervious to helium. As a result, weather balloons tend to progressively loose their helium, and thus eventually return to the surface, although many may in fact explode at high altitude. The attached equipment (e.g., a radiosonde) usually includes information about the origin of the balloon: if you find one, you are supposed to return the entire device to the meteorological service that launched it originally. --Michel M Verstraete22:50, 19 June 2006 (UTC)[reply]
Soccer balls and helium
I've always thought it would be cool to play football with a helium-filled ball. However, football (soccer) balls have to be the same size and weight, so the actual ball would have to be weighted-down. Would a weighted but helium-filled ball act differently (in terms of flight and control), or would it be the same a normal air-filled ball? Ā SLUMGUMĀ Ā yapĀ Ā stalkĀ 17:11, 16 June 2006 (UTC)[reply]
I suppose you are effectively redistributing the mass so that a greater proportion of it is at the surface of the ball. Wouldn't this increase the angular momentum of a rolling ball?Keep it rolling a little longer. Just a guess. ike989817:22, 16 June 2006 (UTC)[reply]
Putting helium in the ball would not redistribute its mass, as all of the mass of the ball would act from its centre of mass, and that has not moved. PhilcTECI23:36, 16 June 2006 (UTC)[reply]
A similar question was addressed on an episode of Mythbusters. Ah, here it is, Episode 47 on that page. They found that there is no significant effect if an American football is filled with helium to regulation pressure. Of course, you asked a slightly different question in which extra weight is added, but at least this is something... 128.197.81.18117:40, 16 June 2006 (UTC)[reply]
I saw that episode, and my recollection is that in fact, the balls filled with helium did not fly as far, because they fluttered instead of cutting through the air. User:Zoe|(talk)02:49, 17 June 2006 (UTC)[reply]
A quick back-of-the-envelope calculation puts the mass of air in a regulation football (at regulation pressure) at about 20 grams. The same volume and pressure of helium masses about 3 grams. Meanwhile, the total mass of a soccer ball is about 400 grams. So the change in mass, while not completely negligible, is pretty small: less than five percent. Redistributing that mass to the shell of the ball will make but a small difference; the bulk of the ball's weight is already there anyway.
Note, also, that regulations specify a fairly broad range of permissible weights for a football: fifty grams or more. In other words, reducing the mass of the football by twenty grams may result in a ball that is still 'regulation', even when filled with helium. It may even be heavier than some other 'regulation' balls. TenOfAllTrades(talk) 18:54, 16 June 2006 (UTC)[reply]
Law 2 of the game specifies the ball to be an air-filled sphere with a circumference of 68ā70 cm (or 27ā28 inches), a weight of 410ā450 g (or 14ā16 ounces), inflated to a pressure of 60ā110 kPa (or 8.5ā15.6 psi)
Of course, the use of helium is prohibited, but otherwise, the ball would be completely legal without having to weigh it down. Therefore, the Mythbusters evidence becomes more relevant. Thanks for all your suggestions. Ā SLUMGUMĀ Ā yapĀ Ā stalkĀ 19:15, 16 June 2006 (UTC)[reply]
Summer Meteor Showers 2006
I want to know which meteor shower is going to have more visible meteors this year: the South Delta Aquarids, on July 28th which are accompanied by a evening crescent moon, or the Perseids on August 12th which are accompanied by an almost full moon. I know that the South Delta Aquarids are about 15- 20 meteors per hour with a possible peak of 60, and the Perseids are about 60 meteors per hour, with a possible peak in the hundreds. Taking into account the moonlight, however, which shower will have more visible meteors this year? David G Brault17:39, 16 June 2006 (UTC)[reply]
I don't know the answer, but suspect it may vary depending on your location, such as Northern or Southern Hemsiphere. StuRat02:00, 17 June 2006 (UTC)[reply]
Thank you. I am living in Maryland, in the U.S. Anybody know the answer? From what I have been reading, it seems like the South Delta Aquarids will be the most dramatic this year David G Brault04:00, 17 June 2006 (UTC)[reply]
If he called these the "Summer Meteor Showers" then naturally he is in the Northern Hemisphere...or else they would be the Winter MS.
and I don't know the answer either, but I'll try to watch these showers here from the Southern Hemisphere (if that is possible) and I'll tell you about which one had the more visible meteors. VdSV9ā¢ā«15:25, 20 June 2006 (UTC)[reply]
Playing Windows games on a Core Duo Macintosh
I just ordered a MacBook Pro to replace my ailing Powerbook. I'm a longtime Mac user, but the fact that the new Core Duo machines can run Windows XP is a definite plus in my book; I like to run a game every now and then. Now this leads to my problem. I plan to buy a copy of XP to install on the machine, but doing this requires using the Boot Camp software to partition the hard drive. You get to set the size of the Windows partition, but I have no idea how big to make it. What kind of hard drive space are games using nowadays? How big should I make this partition if all I'll ever use the Windows partition for is gaming? I don't think I'll ever have more than a game or two on there at once. Thanks, ā BrianSmithson17:51, 16 June 2006 (UTC)[reply]
Some of today's larger game environments can sequester up to 5 gigabytes of storage, but most probably wont need more than 2.5Gb. Assuming that the smallest possible hard drive you could have purchased is 40Gb, I would partition 10Gb to Windows (leaving at least 30Gb to the Mac), as the operating system and all it's buddies take up some space too.Tuckerekcut18:13, 16 June 2006 (UTC)[reply]
If I remember correctly, the last time I had Diablo II installed on my computer it took up approximately 2 GB of space. Tuckerekcut, I assume you meant "B" as in byte and not "b" as in bit. Windows XP can take up about 2GB of space (I think). --M1ss1ontomars2k4(T | C | @)00:26, 18 June 2006 (UTC)[reply]
HTML .chm files in a program
Is there a way to include multiple help .chm files onto a program's installer and then have a way to code it so that depending on the end-user's license information will be pulled from the appropriate .chm? Basically, I want to know if I can put two chums on my installer and be able to tell the program to pull from the right one depending on licensing.
An unregistered IP edited brine to list brines used in the pharmaceutical industry. When I went to wikify that edit, I noticed it included glycol brines and methanol brines, in addition to those of NaCl and KCl. What are these? I thought a brine was a concentrated solution of water and a salt. I took those two out of the list, but I'm asking those of you who are chemistry experts if they should be added back, what it means, and what if any wikilinks are appropriate. --Ginkgo100talk Ā· contribs19:13, 16 June 2006 (UTC)[reply]
Well, as a practising University lab chemist, 'brine' to me specifically means NaCl in H2O. However, I can see how others might interpret it as a solution of NaCl in anything, including MeOH or glycols. Since the person seems to know a bit about what goes on in the pharma industry, I'd be tempted to leave it.--Chris22:07, 16 June 2006 (UTC)[reply]
Yes, but the other editor specified (and numbered!) four kinds of brine: NaCl, KCl, glycol, and methanol. No mention of water; I just assumed water was present in all four. No citation. Maybe someone else knows a source? Chemistry is not my subject and I'm not even sure how to go about searching for verification. --Ginkgo100talk Ā· contribs03:54, 17 June 2006 (UTC)[reply]
Certainly "brine" is a solution of salt in water. No idea if in chemical engineers' jargon any liquid that freezes below 0 Ā°C and is used for cooling a vessel can be called brine. Dr Zak22:49, 16 June 2006 (UTC)[reply]
This article from the American Society of Heating, Refrigerating and Air-Conditioning Engineers, shows how the word "brine" has come to be applied in the refrigeration industry in a generic way, to mean any secondary refrigerant: "In many cooling applications, heat is transferred to a secondary refrigerant, which can be any fluid cooled by a primary refrigerant and used to transfer heat without a phase change. These liquids are also called brines, secondary coolants, and heat transfer fluids." Googling for secondary refrigerants reveals more substances called "brines" in this sense. --Seejyb21:45, 17 June 2006 (UTC)[reply]
Global Warming
I have heard that as the icecaps shrink less light gets reflected back to the sun and therefore absorbed--heating the earth up (makes sense), causing Global warming to snowball as the earth gets warmer....
Wouldn't the opposite be true? Back in the ice age, why didn't the ice continue to cool the earth...allowing the ice to expand further, and thus cooling it further, until the earth was completely frozen?
because there are other things affecting the warming/cooling of the earth, besides this reflection. (Cj6723:10, 16 June 2006 (UTC))[reply]
There are many factors tending to stabilize the Earth's surface temps and other factors tending to destabilize it. One factor tending to stabilize it is that a hotter object (like the Earth), inherently radiates off more heat than a cooler object, all other factors being equal. StuRat01:45, 17 June 2006 (UTC)[reply]
The feedback between surface albedo and temperature has long been known and studied by climatologists; it works both ways (more ice further cools the climate, less ice further warms it). See the albedo article for a start. But, as indicated above, this only explains the maintenance or intensification of a trend. Since paleoclimatologists have evidenced frequent changes from warm to cold periods and conversely, there must be other factors that are over-riding this simple feedback. On 19 June 2006, a search on Google for 'albedo temperature feedback' gave over 220,000 pages... A good starting point for many such climate-related issues is the IPCC reports available from http://www.ipcc.ch/. --Michel M Verstraete23:05, 19 June 2006 (UTC)[reply]
hi, having just asked an acne-based question i thought i'd complete the image with a question on penile smells....
now, i'm really rather high maitenance (it pains me to admit it, but its true) so i wash often (once or twice a day, depending on exersize taken) and eat reasonably healthily. i dont smoke, i dont drink too much (a bit of binge drinking once a fortnight but whose counting) and i don't do drugs....and yet recently i've been getting less than pleasant smells from under my foreskin-there's no discharge and the smell remains regardless of how many times "it" (whatever the technical term is)has been washed. is there a "bad smell" season or are there foods i should be eating/avoiding? does masturbation frequency have an effect? any thoughts would be much appreciated as i'm going travelling soon so would want to be a good ambassador...... thanks! 87.194.20.25321:56, 16 June 2006 (UTC)[reply]
If you are genuinely concerned you should see a doctor. My understanding is that masturbation could be a contributing factor (as it will stimulate the production of secretions), however the smegma article (and links therein) may address some of your concerns. Rockpocket00:27, 17 June 2006 (UTC)[reply]
I was wondering why it is that the rate of cancer in our society today seems much higher than it was in years and centuries past. So this is a two part question: is this really true and why is this the case? I realize that this is a complicated question with no simple answer, but I was wondering if someone could explain it just a little. Thanks! Andromeda32100:05, 17 June 2006 (UTC)[reply]
Because people live long enough to get it rather than dying of other causes.
Agreed. Since 100% of people still die, and far fewer die of some things, like bubonic plague, that means far more people must die of other things, like cancer, to keep the death rate at 100%. (If we ever fall short of the 100% death rate, then people will start living forever, and we can't have that, now can weĀ ?) StuRat01:35, 17 June 2006 (UTC)[reply]
Others claim that cancer rates have increased due to an increase in carcinogens in our evermore polluted environment and modern lifestyle. Melanoma, for example, is thought to be on the increase, possibly because high risk individuals become exposed to more UV at a younger age. This may be due to a combination of factors: an increase in intercontinental travel (childhood holidays to hot climates), because northern Europeans have colonised hot countries over the last few centuries, the fact that suntans have only become fashionable over the last 50 years and that UV exposure levels may be increasing due to ozone depletion. Then there are the hundreds of thousands (or perhaps millions) of past and future cancers that may or may not have been caused in part by radiation exposure after Nagasaki, Hiroshima and Chernobyl. Rockpocket07:56, 17 June 2006 (UTC)[reply]
Chernobyl is probably still significant statistically in Eastern Europe (where entire countries were exposed), Hiroshima and Nagasaki, probably not. There are more people killed by lung cancer alone in the United States per year that died as a result of the bombing. (As for its contribution to worldwide fallout levels, anything it would have added was no doubt overshadowed by the decades of atmospheric nuclear testing which followed). --Fastfission15:46, 17 June 2006 (UTC)[reply]
Many types of cancers are also lifestyle diseases, and you'd probably want to know trends of known carcinogens consumption as well (i.e. cigarette smoking, which can take decades to develop into cancer). I'm also guessing that there are other man-made issues such as coal pollution that come into play. Cancer is a complicated disease and its causal mechanisms are still being studied; additionally there are statistical questions (as noted above) which come into play, and it doesn't help that almost every cause has some sort of political aspect to it (making them endlessly disputed). --Fastfission15:46, 17 June 2006 (UTC)[reply]
Is it possible to pull your own head off?
This may be the stupidest question of the day, but is it humanly possible to rip off one's own head? If I were sufficiently strong and motivated, by insanity, PCP, or boredom, would it be possible to decapitate oneself by pulling? I know for a fact that people's limbs have been pulled off by machinery. Follow-up question: would it be possible to sever one's own head with a hand-held knife, e.g. a machete? Don't ask me why these things are on my mind. Bhumiya (said/done) 00:20, 17 June 2006 (UTC)[reply]
I think both of those things are physiologically impossible, because even if you have strong mental motivation, the pain is so intense that your reflexes take over and prevent you from continuing. That's why people have to literally "fall" on their swords to commit suicide, because their reflexes prevent them from simply stabbing themselves. āKeenan Pepper00:28, 17 June 2006 (UTC)[reply]
You don't have to fall on your sword. People are perfectly capable of stabbing themselves to death (hara-kiri, for example, or even just wrist-slitting with subsequent bleeding). Cutting off a limb is also possible. Ripping off might be another matter, and the head would be yet more difficult as you would be unable to move your arms after the spinal cord was severed, rendering that feat, I think, pretty much impossible. - Nunh-huh02:29, 17 June 2006 (UTC)[reply]
It's big. The "Myth Busters" did a segment in which they explored the possibilty of decapitation by ceiling fan, and discovered it took a lot of force to sever a head - more than they were able to develop. Obviously it would be a great deal more to pull it off by blunt force. - Nunh-huh02:39, 17 June 2006 (UTC)[reply]
I imagine, and this is just speculation, that if PCP were to remove all pain and/or care about pain, then one might be able to pull one's head so hard as to sever the spinal cord, at which point it would be impossible to continue to pull one's head the rest of the way off. --Ginkgo100talk Ā· contribs04:00, 17 June 2006 (UTC)[reply]
I think that sounds reasonable, but then again, PCP addicts have done some pretty astonishing things to themselves. I remember reading about someone who peeled his face off with a broken mirror. Of course, this is different. I think if I were an abnormally strong individual with no sense of pain and a desperate, irresistible urge to decapitate myself, it might almost be possible, if I began by tearing up my neck and then snapped the spine with a single forceful jerk before I had the chance to bleed to death. The harder I think about it, the less plausible it sounds. Still, it might make for an interesting episode of CSI. Bhumiya (said/done) 05:39, 17 June 2006 (UTC)[reply]
Both this chap and this chap seem to have enough will power to cut off parts of themselves. Cutting of your own head would be a bit harder, due to the fact that you would lose conciousness pretty quickly if you didn't manage it on the first attempt and that its hard to think of a good reason for doing it to focus your mind. But that aside, i bet it would be possible with a long enough and sharp enough blade and enough power in your arms to generate the force required. I bet some of those samurai dudes could do it. Rockpocket07:42, 17 June 2006 (UTC)[reply]
I think it would be extremely unlikely for it to happen, unless perhaps you had some kind of defect that made you have weak neck bones that would allow for the possibilty to pull off your head. A possible scenario would be this: Your head was "loose" to begin with (meaning you had some kind of bone disease or other ailment) plus you had strong arms, which would be unlikely considering how close the neck/head is to the shoulders. I wonder if anyone has actually pulled off their head out of the billions of masses. --Proficient16:06, 17 June 2006 (UTC)[reply]
Maybe not, but a lot of people over the years have been told to pull their head in. A terribly rude injunction, I've always thought. There are so many more pleasant ways of telling a person their existence is no longer required. (lol) JackofOz00:54, 18 June 2006 (UTC)[reply]
Help
Hello, Iām hoping you could provide me with some help. I have a physics final on Monday, and we got a review package that resembles nothing of the kind of stuff weāve done in class. I hope these arenāt too many, here goes:
When a certain rubber band is distance x, it exerts a restoring force F = axĀ²-bx, where a and b are constants. The energy stored in the rubber band when stretched from x = 0 to x = L is:
a) 2aL āb
b) 2aL+2b
c) aL^3/3 + 2bL
d) -aL^3/3 + bLĀ²/2
e) aL^/3 + bL/2
The correct answer is d. I have no idea how to get that, and the only reason I think it might be d is because it has a negative in front of the a because the Force is opposite the x
The next question: A 1kg mass moves in a straight line under the influence of a force. The potential energy is given by U(x) = 6xĀ²-2x^3 where U is in joules and x is in meters. If the mass has a speed of 2m/sec when it is at x = 1 meter, its speed when it is at x = 0 is:
a) 0
b) 2 ā2 m/sec
c) 3ā2 m/sec
d) 2ā3 m/sec
e) 2ā6 m/sec
The answer is d. I am confused with this problem because it says ā mass moves in a straight lineā, and then it mentions potential energy, which must be 0 because the object has no height. Extremely confused with this one, I think the formula might just be a trick and not actually be useful, but I have no idea. Afterwards in the next question, it asks for the acceleration (which turns out to be -6). If I knew how to do the above question I might be able to do the one after it, but Iām unsure and just completely lost. Any response would be very appreciated. ā Hopelessly Screwed
I don't think we're supposed to answer homework problems, but too bad.
For question 1: When you stretch the rubber band, you're doing work on it against the restoring force of the rubber band. The key is that work (which is a form of energy) is given by . That is, the work done is the integral of the force exerted along a path (a negative sign is needed if "F" is the restoring force instead of the force exerted). In this case, the expression for the work is (note that the signs are reversed because the work you do to stretch the band is the opposite of the restoring force). Hopefully you can integrate that to obtain
As for question 2, what they mean by "the mass travels in a straight line" is that it is restricted to the x dimension; i.e. there are no other dimensions in which to move. The problem is asking you to consider an arbitrary potential energy, not necessarily the potential energy due to gravity, so "height" is not an issue. For instance, this could be the potential energy of a spring that a mass is pushing against.
The key to this problem is conservation of energy. No matter where the mass goes, it's mechanical energy (potential energy + kinetic energy) will not change, (assuming no non-conservative forces like friction). Therefore, if you can figure out its total mechanical energy at some time, it will be the same at all other times. In this case, the potential energy depends only on position; you are given the expression , and kinetic energy is given (as always) by .
At some time, the problem says the mass has velocity 2 m/s, so it's kinetic energy is (1 kg * (2 m/s)^2)/2 which comes out to 2 Joules. At that time, it is at x = 1 m, so its potential energy is 6 * (1^2) - 2 * (1^3), which comes out to 4 Joules. Therefore, at all times (unless some outside force acts on it), its mechanical energy will be 6 Joules. When x = 0, the potential energy of the mass is 0 (zero), so the kinetic energy must be 6 - 0 = 6 Joules. Now, you can use the kinetic energy formula in reverse to figure out the velocity. This gives sqrt(2 * 6 Joules / 1 kg) = sqrt(12) = .
By the way, a hint for finding the acceleration at x = 0: Since , and always remember that where "a" is acceleration.
In the first question, force is dependent on . Differential work done when stretching the rubber band by a length of is . Work done in stretching rubber band from to is .
In the second question, it is not stated whether the force is position-indepdent (i.e. indepdent of ). To get an answer, some assumption is needed. Perhaps the unstated assumption is that the force is constant. With that assumption, you can calculate the work done, and therefore the increase in total energy in moving the mass from to . The total energy of the mass at position is the sum of its kinetic energy (related to its speed) and its potential energy (given by the formula for ) at that position. Given the boundary conditions, you can work out its initial kinetic energy (and therefore speed) at .--72.78.101.6105:11, 17 June 2006 (UTC)[reply]
It just occurred to me that in my interpretation of the second question (i.e. the "force" is external and not accounted for by ), the question does not provide enough information to allow an answer to be calculated. Maybe Bmk's interpretation is the intended one.--72.78.101.6105:43, 17 June 2006 (UTC)[reply]
"We haven't done calculus yet so I'm unfamiliar with integrals. Is there any other way? Thanks for helping!"
Not sure where I heard this, but I heard that orange peelings can be used to cultivate antibacterial agents such as penicillin. Am I completely wrong about this, or is there some truth to it?--24.231.16.10904:40, 17 June 2006 (UTC)[reply]
Penicillium mold grows easily on orange peel. Just leave some oranges in a drawer or even your refrigerator too long and you will proabably be rewarded. Extracting the penicillin will be your challenge and you may want to make arrangements with your local pharmaceutical company to use their purificaction and testing facilities over a weekend, if you don't have a sterile separation and analytical lab in your basement. Next you will want to borrow some culture petri dishes and bacterial cultures in the microbiology lab of your local hospital to prove the stuff works. Good luck. alteripse11:15, 17 June 2006 (UTC) PS: Keep in mind of course that penicillin costs maybe 10 cents a tablet.[reply]
Optics glossy/matte colours
OK, I want to explore different colours and how you can make them different. One aspect is the colour itself. Anoter aspect is the gloss, whether the colour is shiny or matte. What other optical aspects can affect the way a colour or surface visually appears? I guess there's also infrared. Can some animals see infrared surfaces? If a surface was truly infrared, what colour would a human see it as?--Sonjaaa06:24, 17 June 2006 (UTC)[reply]
Translucency springs to mind. And yes, some creatures (such as certain species of insect) are capable of seeing infra-red. Provided all non-infrared light was absorbed, a human would see such a surface as blackGeeJo(t)ā(c) ā¢Ā 07:30, 17 June 2006 (UTC)[reply]
The alkyl groups are electron-donating and thus strengthen the O-H bond in the alcohol. This makes the alcohol a weaker acid and less likely to lose a proton to be reduced by the sodium metal. The more alkyl groups present, the more electrons get pushed into the O-H bond. G N Frykman17:30, 17 June 2006 (UTC)[reply]
software testing
Hi,
i would like to know about the most used software testng tools and why the thes tools are usedĀ ?? I would also like to know about the comparitive advantage with other tools
Regards
Tommy
Tommy, I think you need to make your question a lot more specific to get a useful answer. What kind of software are you referring to? What OS? From what point of view (data integrity, user friendliness, vulnerability to malicious attacks, etc). --vibo56Ā talk19:23, 17 June 2006 (UTC)[reply]
hi my old laptop has not worked for a month for so now
its a bit expencive to get fiexd, so i lent it to a friend who sead they would look at it. they say it has a bios virus, i was wondering what a bios virus is?
That would be a Computer virus which has somehow affected your computer's Basic Input Output System. The BIOS is a small program that tells your computer how to startup. Although BIOS viruses are said to be rare, once your BIOS has been corrupted, there is not much that can be done. The term itself is a little misleading, as the virus does not "live" in the BIOS and can not replicate itself from there. But if your computer has been affected, the terminology is the least of your worries. --LarryMac20:33, 13 June 2006 (UTC)[reply]
Laptops are tough. CMOS is located on your motherboard so you either have to open it up to expose the motherboard (NOT recommended) or ask your Dell/IBM/HP guy. -- ŠŠøŠ±Š¾ŃŠ¾Š²ŃŠŗŠøŠ¹22:27, 14 June 2006 (UTC)[reply]
Well where does the BIOS virus reside if it does not 'live' in the BIOS? And would 'flashing the CMOS' work? To do that, do I have to jump some pins or something? --217.44.0.21210:56, 17 June 2006 (UTC)[reply]
Maybe a BIOS update will correct your problem by overriding the defect. What is the exact problem with your comptuer when you say that it's not working? Is the operating system not functioning, the computer not turning on at all, or something else?--Proficient11:17, 17 June 2006 (UTC)[reply]
To clarify, a BIOS virus should be removable by flashing (not possible if you're already at newest version, though) or by resetting CMOS by removing the battery (CMOS battery, not laptop battery) for a few minutes. It can also generally be done by changing a jumper connection. But either of those ways requires touching the motherboard - not easy on a laptop. -Goldom(t)(Review)11:44, 17 June 2006 (UTC)[reply]
Reccommended procedure:
Verify the claim that there is a problem with the bios. To do this, you might check if the laptop boots normally with a bootable CD such as knoppix. If this is successful, the problem is probably not with the bios.
If you want to restore bios factory defaults, you can normally do this from within the menus of the bios setup program. If you pay close attention while the pc starts its boot sequence, you will see a message which tells you how to open the setup program (it might be, for example, holding down the F2 key when the pc starts). A text mode setup program will open, with a menu. Somewhere, usually on the "Exit" menu, there is an option "Load Setup Defaults". If you are certain that the bios is messed up, this should restore it. You also need to "Save changes" before exiting. --vibo56Ā talk13:35, 17 June 2006 (UTC)[reply]
Schrodingers Equation
Ok i know the what the equation looks like but how do you solve it for a given
particle of some mass whose energy contribution is V(x,y,z)using the equation. could you show it using an example. how do you solve the hamiltonian?
--Debanjum11:59, 17 June 2006 (UTC)durin[reply]
could you be more specific - when you say the energy contribution is v(x,y,z) do you mean that its energy is a function of its position in 3 dimensional space? What do you want to do? find the wavefunction that satifies certain conditions or what?HappyVR15:16, 17 June 2006 (UTC)[reply]
Here's something which has been on my wish-list for awhile. I'm wondering how difficult it would be to pull off.
Basically, the program would be a web browser which could simulate a locally hosted Apache server. Why do it? Because then you could write applications in server-side languages like PHP and distribute them to people easily. No need to install a whole Apache server on their machine if it is just going to be run locally. If you could combine PHP, Apache, etc. into a browser-like application itself, then you could easily distribute PHP files to people and not have to worry about all of the idiosyncracies of actually installing a server.
Does that make sense, conceptually? I want a way to easily distribute PHP programs which are made to be run off of the local machine (and not as true web applications), but the only way to currently do that is to install Apache and PHP (not simple operations, and overkill). It seems like it shouldn't be impossible to have a browser-like-application which could itself replicate the behavior of a local server.
I'm not aware of any such beast. If you want to avoid installing PHP, you would either have to integrate the PHP interpreter source code into your browser code, or write your own PHP interpreter. The former is not tempting to me from a maintenance point of view, and the latter is reinventing the wheel. I'd say both sound like a lot of work. But I agree, it would be nice if the user could just download the PHP+ServerEmulator plugin, and be ready to use your PHP program. --vibo56Ā talk19:40, 17 June 2006 (UTC)[reply]
What I was hoping one could do is just integrate Apache into the browser and then integrate PHP into that. I don't know how much re-inventing you'd have to do ā all of the code for PHP, Apache, Firefox, etc. is open source.. it's just a matter of fitting it all together neatly, I suppose. Which is probably hard.Ā :-) --Fastfission05:20, 18 June 2006 (UTC)[reply]
One approach might be to write a user-friendly installer that installs a browser, web server and PHP interpreter at the same time. Getting it right is not easy, however. A similar thing has been done for the windows version of LyX, but I have not been able to get the installation to work properly on my system (now trying again, uninstalling everything, reinstalling each package separately). --vibo56Ā talk08:45, 18 June 2006 (UTC)[reply]
Biological classification systems
I was wondering - regarding the classification system of plants and animals: Is there an official board or similar organisation that decides when a new classification is valid. Some of the reclassifications I've seen seem to be based on published papers - which makes sense since these things are peer reviewed - but surely getting a paper published is not all that it takes - maybe some sort of consensus rules here, I've honestly no idea how it works in practice - I assume differences of opinion do arise - how are these sorted out? Are disagreements amongst biologists worked out in a similar to conflicts on wikipedia?HappyVR16:09, 17 June 2006 (UTC)[reply]
I look forward to an answer to this question, but I sure hope that no one in the real world resolves conflicts like we do! Melchoir18:51, 17 June 2006 (UTC)[reply]
Thanks, but I'm not sure if this was the answer I was looking for - the links you provide guides to the nomenclature of species, but I was thinking in terms of when a conflict occurs regarding the placement of a given species within one or another genus - ie issues of taxonomy not naming - can anyone help?HappyVR19:47, 17 June 2006 (UTC)[reply]
I'm sorry, i misunderstood your question. This article seems to suggest the peer reviewed publication process is how one establishes new taxonomy. One assumes, like the scientific process in most disciplines, time determines whether the community will accept the proposal, based upon further work supporting or refuting the evidence. Like everything in science, there is often no "right" answer, it comes down to who has the most convincing argument.the answer to this posting would seem to support this. Rockpocket00:14, 18 June 2006 (UTC)[reply]
Thanks, that pretty much answers it. I was wondering if there was an organisation that 'rubber stamps' these things such as the Linnean society or 'international body of biological scientists' - I don't suppose 'rubber stamps' are in keeping with the scientific ethic though.HappyVR00:58, 18 June 2006 (UTC)[reply]
Taxonomy is a science and it is normal to have dissensions with new theories. The dispute between traditional taxonomy and cladistics is beginning old and is still sometimes in the focus of science media. What are the criteria to sort life formsĀ : form itself, bones, tiny characteristics, genesĀ ? This also a question of fashions, which must evolve. --DLL20:29, 17 June 2006 (UTC)[reply]
See International Code of Botanical Nomenclature for the WikiPedia article relating to plant taxononmy. For botany, the fights seem to be fought at the congresses where the code is decided (next one due this year?). An interesting story giving some insight into the process is: The name Acacia retained for Australian species. As far as zoological toxonomy is concerned, the situation seems to be less formal, confirming what Rockpocket said. Butler says the following in his article on the issue of Pituophis Taxonomy (I quote the whole paragraph to make the context clear, the editor's note is the pertinent bit): "Before we discuss Pituophis, I first must describe the formal and informal processes of taxonomy. Formally, there are two groups that make decisions on the names of species; the American Association of Zoological Nomenclature, which is a satellite-organization for the International Commission on Zoological Nomenclature (ICZN). Generally, if there is a published dispute regarding the name of a species, the authors will present their case to the ICZN, and they will make a ruling based on their established code. However, more typically and informally, once a name sticks, and is used frequently, then the ICZN rarely gets involved. (Ed. Note: The ICZN judges on procedures and does not get involved with species validity - that is the purview of peer reviewed journals.)" So "peer reviewed journals" seems to be the case for zoology. --Seejyb11:04, 18 June 2006 (UTC)[reply]
The various naming committees (ICZN, ICBN etc) adjudicate a very narrowly defined set of issues to do with biological names and biological types. So questions like, "what is the type specimen for the species Homo sapiens?" or "is the name Archaeoraptor available (in the technical sense of 'available')?" are appropriate for the committees. But questions about actual relationships, like "how many genera of gibbons are there?" are outside the scope of the committees and must be settled by research, peer review, and debate. Gdr11:19, 19 June 2006 (UTC)[reply]
Sinking lifejackets?
I have heard an urban legend that the "old" lifejackets made of cork or kapok used to lose buoyancy after being immersed in water for a long (many hours) period of time? Can anyone confirm or deny this? Thank you for time. Mieciu K14:08, 15 June 2006 (UTC)[reply]
According to this NOVA transcript, early cork lifejackets had many problems: "The buoyancy is equally distributed around the body, around the front of the body and around the back of the body. So, if the person was unconscious and was lying face down on the water, he would remain stable in that position. Secondly, there was no support for the head or neck. It's really just wrapped around the top of the body, leaving the shoulders and head out of the water. And that's fine for somebody who is conscious, who is alert, who is able to hold his head out. But the head actually is very heavy, the specific gravity of the head. When a person loses consciousness, the neck muscles are failing, and then the head tends to flop forward, and they could be found floating face down in the water, inhaling the water." However, I can find no reports of cork or kapok lifejackets actually breaking down and losing their buoyancy. I would expect that cork would be fairly resilient. Consider how long corks survive in bottles of wine without breaking down. Then again, cold water might have a different effect. Also, any lifejacket, even one made from synthetic fibers, can break down if it develops a tear or becomes infested with mold, mildew, etc. I think the Indianapolis survivors may have had problems remaining upright. Their unbalanced lifejackets would have required them to constantly maintain their balance in the water. If you lost consciousness or became too tired, it would be easy to turn over in the water and drown. But I can find no evidence that life jackets actually sunk. Bhumiya (said/done) 01:36, 18 June 2006 (UTC)[reply]
IIS
I might be migrating from Apache to IIS sometime soon (and hence PHP -> ASP.NET). Here are a few questions...
Is there an ASP.NET interfact for PhpBB? I have a lot of mods and I don't want to have to migrate my phpBB installation into another app.
Is there a system similar to Cutenews for ASP.NET that is free? All I want is to be able to post news that is integrated into my frontpage. I'm able to design the rest.
Is Web.config analogous to .htaccess? If not, is there a directory-level configuration file? Becuase I need to be able to define custom 404, etc. files as well as disable directory listings for certain folders, etc. And I share hosting with my dad, so I'm a subdirectory of his site.
ASP.NET and PHP are two entirely different programming languages. phpBB and any mods you have for it will only run under a PHP interpreter. However, it is certainly possible to run PHP scripts under IIS [10], just like it's possible to run ASP.NET code under Apache [11]. So, you can either contact your hosting provider and see if they support PHP, or move to a different forum package written in .NET. (here are some possibilities)
From browsing Google for information about Web.config, it does seem to serve roughly the same purpose as .htaccess. However, I'm not all that familiar with ASP.NET myself, so you'll have to ask somebody else if you have any detailed questions about it.
web.config is kind of the same as .htaccess, in that you can define application settings, including 404s (for .net processed files only, for example .aspx, but *not* for .html, because that's served up by IIS directly). Directory listings are, again, controlled by IIS, not asp.net. Once IIS7 comes out then web.config will run the whole show. Whilst I don't know of a direct cutenews replacement [DasBlog] is a .net blogging engine that uses the file system, not a database. I guess it depends what bits of cutenews you want replicated. --Blowdart23:36, 17 June 2006 (UTC)[reply]
Just something that can display news on the front page using a design template that I give it. And then I can do something like I do include(...); in PHP ā Ilyanep(Talk)03:51, 18 June 2006 (UTC)[reply]
I've not seen something like that. And include isn't part of asp.net, you would have to embedded it as a custom control. It doesn't look hard to code, so I'm sure there must be something out there. --Blowdart15:44, 18 June 2006 (UTC)[reply]
Well, I understand there'll be some differences between PHP and ASP.NET, but I just don't want to have to get a package that essentially codes a whole website for me. ā Ilyanep(Talk)16:50, 18 June 2006 (UTC)[reply]
Use of cows milk vs. soya milk and toothpaste
Gillian McKeith states that cows milk is bad, and that you should only drink soya milk (which I have now been doing). She states that it forms some sort of mucus on the stomach lining and that is only for use on a calf (the milk). Is she right? Also, I have begun using normal toothpaste with whitening toothpaste, using the the normal first then the whitening. Will the two toothpastes cancel each other out? Thanks, Kilo-Lima|(talk)17:24, 17 June 2006 (UTC)[reply]
Whether cow's milk is "bad" you might like to consider that generations of people in many (though not all) cultures have been doing it for a very long time, and that our current expectations of longevity and health are mainly concerned with people who have been drinking it at some time. You might like to consider what actual or potential problems cow's milk is claimed to cause, and consider whether there is any evidence that this is in fact the case, perhaps by comparison with other cultures who don't drink cow's milk. I have never heard of this person, but I would also check for a secondary agenda, for example whether she is also an advocate of animal rights, who might consider it desirable to reduce the many animal deaths caused by drinking cow's milk, and if so, whether you share that agenda.
If anything, using two toothpastes will only help. I don't see what's wrong with doing a double whitening though. ;o --Proficient19:56, 17 June 2006 (UTC)[reply]
Are you complaining about the "London, England" bit on that page, because that's the only part I could see that you could make that comment about; and it is, obviously, accurate. --Blowdart23:37, 17 June 2006 (UTC)[reply]
Ms McKeith is likely referring to rennet, since there is nothing else resembling her fanciful notion of a milk-specific "mucous lining" in calves. Soy milk as you buy it is a highly modified synthetic product. The rate of allergy is 5 to 20% (see [12]) and there is about a 50% cross-allergy with cows' milk. For young woman, skim milk would be the drink of choice, since soy contains neglible amounts of calcium. Apart from allergy differences, and the different fat compositions of the two products, there is no scientific proof that there is any benefit in drinking synthetic milk (see [13]). In the two books of this person that I have read, it is sometimes difficult to decide whether the writer is naively propagating untruths as valid science, or whether she is deliberately lying to make money. --Seejyb09:30, 18 June 2006 (UTC)[reply]
I don't know about this "mucus-lining" stuff, but there is no evidence whatsoever that drinking milk decreases your risk of osteoporosis. Check this study by the Harvard School of Public Health out. Here's a quote from the conclusion of that study: "An adequate vitamin D intake is associated with a lower risk of osteoporotic hip fractures in postmenopausal women. Neither milk nor a high-calcium diet appears to reduce risk." It's an amazing dairy-industry conspiracy - somehow everyone thinks milk keeps your bones healthy, but it just doesn't seem to be true. And as for soy milk, I don't know what Seejyb means by "a highly modified synthetic product". It's made with a very old process developed in the 1st century BC (see Soy milk) It's basically, "grind the beans in water, then strain out the milk". --Bmk13:56, 18 June 2006 (UTC)[reply]
An article about postmenopausal woman and calcium intake has absolutely no bearing on the recommendation that woman between puberty and 30 years of age should ensure that they have an adequate calcium and vitamin D intake as well as plenty of exercise. Inferring from such a study the recommended intake for young women in the window period when calcium intake does seem to make a difference to bone density for the rest of their life is irresponsible. How we get our calcium is irrelevant, and drinking three glasses of skimmed milk, or of soy milk to which calcium has had to be added (check the ingredients), or one and a half effervescent tablet in water probably makes little difference, except to the cost of the calcium. The soy bean, when not properly ("highly") processed contains significant levels of anti-nutritionals, as well as phyto-estrogens, which does seem to worry some scientists, since the levels of intake of soy products in the western world far exceeds that of the eastern countries where soy milk was traditionally consumed. As far as conspiracy theory goes, one has the uneasy feeling that the soy-derived ingredients in processed foods may eventually turn out to be not as harmless as claimed by the very powerful producing groups; they certainly spend huge amounts of money to promote it as "healthy" or "natural", which is patent rubbish - it is as natural as coffee, at best. In the east soy was not normally used as a basic food, the way the west does at the moment, so that the long-term effects are difficult to judge impartially. This is made more difficult by the fact that interested parties tend to promote only the research that benefits themselves (e.g. dairy producers vs soy bean producers) --Seejyb01:12, 20 June 2006 (UTC)[reply]
It's more massive, so you have to hit it harder to knock it over. I don't know if you're aiming for something more profound...? Melchoir18:48, 17 June 2006 (UTC)[reply]
I agree with Melchoir. If you have an empty can and a full can you can do a very simple experiment to see if there really is a difference: Push the very top of the empty can a tiny bit then let go. If it doesn't fall over, push the same place a little harder, let go, repeat until it falls over. Do the same again with a full can and see if you have to push them the same distance until they fall. Obviously you'll have to push the full can harder because it is more massive, so you'd want to pay attention to distance or angle and not force. 128.197.81.18118:58, 17 June 2006 (UTC)[reply]
Wellll... it all depends on what one means by "more stable" anyway. The major difference between the two cases will be the force, not the angle, required to tip the can. Melchoir19:10, 17 June 2006 (UTC)[reply]
Maybe, but the dynamics of a rigid body are determined by its mass and moment of inertia as well as its center of mass. Melchoir19:06, 17 June 2006 (UTC)[reply]
Aha! I think you may have hit on it here! Its probably the moment of inertia that is much smaller when empty. But Im going to do a few experiments with a large number of full, then empty cans! How they get from full to empty, Ill leave to your imagination!Ā %-)--Light current19:15, 17 June 2006 (UTC)[reply]
Yes: the suffering we have to endure in the persuit of knowledge! Yes! now the result of drinking the first can experiment! Comparing a full can with an empty one I noticed that the max tipping angle was approx the same for both. (say 30 deg from vert - I didnt actually measure it). But, if the cans are pushed below this critical angle and then released, the full can regains its upright position with no oscillation, whereas the empty can totters back and forth quite a few times before coming to rest. Any ideas on that one? Anyway, must get back to the lab!Ā %-)--Light current19:48, 17 June 2006 (UTC)[reply]
I'm writing a fictional work (actually a Live action roleplaying game) in which somebody needs to build a simple bomb. According to time bomb, all one really needs is a battery, a watch, and some explosive material. What kind of explosive material? Where would a teenager on a colony on Triton (a new colony, not so different from the stereotypes of the American Old West) get such a thing? Like, if there's blasting crews on the colony, could he just lift some? What are the steps involved in making a bomb? I looked for instructions for building a simple bomb online, but it turns out it's less widely available than the scaremongers would have you think. And I don't need to actually do it myself, just describe in very rough terms what would be needed. moink19:58, 17 June 2006 (UTC)[reply]
Just make sure to explain that you character was well-trained in his former life, including Afghan, Irish, &c. references, and do not go into bomb making detailsĀ : the reader shall know enough. --DLL20:15, 17 June 2006 (UTC)[reply]
Hmmmm... I'm trying to make him a pretty lame loser character who doesn't really know what he's doing, but does some really basic research and figures out how to build a simple bomb. We're trying to make it hard for him to accomplish this, since it screws over the other characters pretty badly if he succeeds. moink20:18, 17 June 2006 (UTC)[reply]
According to Triton (moon), there is a lot of Ammonia present. Methane and Nitrogen are abundant in the atmosphere. If you have some water, I'm sure a chemist could whip something up for you. Dmnā¬Ō“Õ“Õ¶11:37, 18 June 2006 (UTC)[reply]
Does it have to be a bomb, or can it just be an explosion? Any fine powder should be very dangerous if it forms a mist. See Flour and Lycopodium. The lycopodium article has links to movies. --Kjoonlee14:51, 18 June 2006 (UTC)[reply]
Well, just something that makes sense for my character to put together from a few different pieces and "set off" while he tries to get away. I think I'me going with C-4 and some wiring and a battery. moink07:43, 19 June 2006 (UTC)[reply]
e-mail address harvesting?
Iāve been getting a lot of e-mails from various phony senders. They are without a subject line, have no content, and are addressed to āunlisted recipients.ā What is going on? Is this some kind of e-mail harvesting, or maybe something worse? --Halcatalyst20:46, 17 June 2006 (UTC)[reply]
Received: from ams018.ftl.affinity.com
(lvs00-fl-n18.ftl.affinity.com?[216.219.253.56](misconfigured sender))
by sccqmxc94.asp.att.net (sccqmxc94) with ESMTP
id <20060617165739q9400idrkae>; Sat, 17 Jun 2006 16:57:39 +0000
X-Originating-IP: [216.219.253.56]
Received: from cust_req_fwding (xxx@dendurent.com --> x.xxxxxxxxx@mchsi.com)
by ams018.ftl.affinity.com id S1610159AbWFQQ5j for
<x.xxxxxxxxx@mchsi.com>; Sat, 17 Jun 2006 12:57:39 -0400
Received: from [82.155.63.77] ([82.155.63.77]:61959 "HELO fdah.com")
by ams018.ftl.affinity.com with SMTP id S1608422AbWFQQ5j;
Sat, 17 Jun 2006 12:57:39 -0400
Message-Id: <S1608422AbWFQQ5j/20060617165739Z+11389@ams018.ftl.affinity.com>
From: <xxxxxxxxx@fdah.com>
To: unlisted-recipients:; (no To-header on input)
Date: Sat, 17 Jun 2006 12:57:39 -0400
It's very possible that the senders have their own SMTP servers, thereby eliminating the need to send a "To" address to another SMTP server and allowing them to directly interact with your ISP's mail servers without having to go through the regular process of specifying a "To" address to a third-party SMTP server. There are many possibilities; spammers use lots of different tricks. -- Daverocks (talk) 12:19, 18 June 2006 (UTC)[reply]
I occasionally get spams with no content, which is rather confusing. A possibility that comes to mind is that they've set up a dummy email account to send from and they're tracking bounced emails to trim down their lists. 128.197.81.18118:28, 18 June 2006 (UTC)[reply]
I suppose if they're sending out a couple million spams it might be useful to delete 300,000 (or even 50,000) bad addresses, especially if they have automated means to update the lists. But it's hard to imagine spammers being that concerned about efficiency. --Halcatalyst19:18, 18 June 2006 (UTC)[reply]
I did hear that there are some spam networks who do this to wind up people who they discover trying to report their abuse (a lot of the bigger spam networks apparently buy thier own IP blocks on the black market so they can control the abuse contacts). Plugwash00:50, 20 June 2006 (UTC)[reply]
You seem to be assuming that futon has a more universal meaning than it actually does. In English, it seems to refer to any sort of folding bed, aka sofabed, though the original Japanese is something completely different and very specific. I slept on a very soft western futon during my university days.
Regardless, if I take your question to mean "If firm beds are considered ergonomic, is a camping mat on a hard floor equally so?" then I can explain why the answer is no. The futon in question (yours, I assume) isn't good for your back because it's hard, but because it only gives to a small degree (hence, firm), allowing your back to straighten instead of lying limp like it would on a very soft bed. A camping mat on a hard floor has no give whatsoever, and thus does not allow for natural body contours and ends up giving you stiff bones in the morning. As a person that rather enjoys sleeping on a hard floor, I can vouch that it is ergonomical to a certain degree, especially after long periods sleeping on a soft bed, but without a firm cushion underneath you quickly develop cricks in your neck and shoulders, and I guess that's why there are so many doctors who cure that sort of thing around these parts in Japan. Ā freshofftheufoĪĪÄæŠĀ 05:28, 19 June 2006 (UTC)[reply]
The alcohol you are referring to is ethanol, right? Otherwise, you probably wouldn't want to drink itĀ :-) ...
If it is wine or anything stronger, I think it would be safe to taste it. And if the taste's ok, I think it would be safe to drink it. But to be on the safe side, wait a couple of days until other contributors have had their say! --vibo56Ā talk00:19, 18 June 2006 (UTC)[reply]
And if they die, the traditional rule for food-tasters applies. They get a cemetery or a crematorium named after them. (lol). JackofOz00:35, 18 June 2006 (UTC)[reply]
The thing is, if the yeast which creates the alcohol is still in there, it can take the alcohol and further convert it to Ethyl Aldehyde, and then to Acetic Acid (vinegar). Usually the yeast is removed to prevent his from happening, and with high content spirits the alcohol content can get to toxic levels for the yeast.
Well, you shouldn't rule out the thought of selling them. Since they are so old, you might get a good deal if you can -prove- that they are 30 to 40 years old. --Proficient14:40, 18 June 2006 (UTC)[reply]
This is something that I first noticed years ago, with my very first pet budgie but completely forgot about until I read all the budgie-related questions on here. Is there any particular reason that when a budgie blinks, its bottom eyelid moves up to meet the top, as opposed to the top eyelid moving down to meet the bottom, as in humans? Is there any particular advantage to this configuration, or is it just a case of two very different species evolving from two very different evolutionary lines and arriving at different solutions for the same problem? --Kurt Shaped Box00:50, 18 June 2006 (UTC)[reply]
Are you sure this isn't a third, inner eyelid you are seeing, in addition to the normal eyelidsĀ ? Cats have this, too, and I assume it's useful for removing debris (like fur, in the case of a cat) from the eyeball. StuRat23:51, 18 June 2006 (UTC)[reply]
Na. It's definitely his bottom eyelid - I've been sat watching him for the past ten minutes. When he blinks, the bottom lid moves up to meet the top one. Go figure. --Kurt Shaped Box11:25, 19 June 2006 (UTC)[reply]
How does my Electric toothbrush recharge itself?
I've got a Braun toothbrush which has a solid plastic casing. I recharge the toothbrush by placing it on a small recharging unit that also has a solid plastic casing. The unit is plugged into the mains, but how does the toothbrush recharge when there are no metal contact points on the charger or the toothbrush?
Assuming you have't missed the metal contacts I'd assume through electromagnetic induction.
A coil of wire with an oscillating (AC possibly highfrequency) current in it would induce an oscillating electric current in a pickup located inside the tootbrush. This could be used to charge a battery. Sorry I can't find a good page to explain the process..HappyVR01:54, 18 June 2006 (UTC)[reply]
You can test this by dangling a small piece of steel inside the charging socket: the metal ferrule on a pencil works well, as should a small screwdriver. If you can feel a vibration, it uses magnetic induction. --Serie20:06, 19 June 2006 (UTC)[reply]
HIV Transfer
If I have a small cut on my penis, and I am getting a blowjob from someone that has HIV or AIDS, will I get HIV? I was reading an article and it mentioned that the HIV virus is in saliva also, thanks
There is risk, but it does not guarantee infection. Any body fluid exchange can carry the virus, but the operative word is CAN, not for certian. Also consider that the virus is fairly fragile, and does not survive very long outside the body. I would strongly reccomend you get yourself checked, this virus is pretty ugly once it gets a hold of you.
I've noticed that some PNG graphics on Wikipedia that are shown with a transparent background within the article actually have a blueish background. Here's an example:
In the article PNG this same image has a transparent background.
Internet Explorer cannot handle transparant PNG images, and often displays them (on Wikipedia) with a blue background. You could try using Mozilla Firefox; that will fix the problem. āMets501 (talk)02:24, 18 June 2006 (UTC)[reply]
I want to know everything about types of sugar like table sugar,milk sugar,starch sugar and fruit sugar. Please help me with this topic.--59.144.254.4903:41, 18 June 2006 (UTC)[reply]
I've recently been asked by an online group in which I'm active if I could establish some sort of web-based file sharing tool... Pictures, audio files, and possible applications. There are several groupware packages that incorporate some type of upload/download for members but, along with that functionality, one is bombarded with features that are not, in this case, needed.
Is there a web-based file sharing package (for linux?) that might work for this group? I've read through File sharing but the article is concerned mostly with P2P stuff. Thanks so much for any guidance you guys (and gals) might be able to provide! --Chiacomotalk04:45, 18 June 2006 (UTC)[reply]
Why is it that some teenage boys/young men are attracted exclusively to women in their 40s? Is there a scientific/evolutionary explanation for this? In terms of reproduction, this would seem to be counterproductive (without trying to sound too veterinary, women of that age are past their prime when it comes to breeding). --84.65.31.24805:48, 18 June 2006 (UTC)[reply]
I'm not sure what you mean by "exclusively". I doubt young/men boys are alone in their lust for women in their 40s (one would think their husbands might also have a sexual interest in them). Nor are 40 year old women the only object of teenage boys desire (otherwise teenage girls wouldn't have many boyfriends). That notwithstanding, its an interesting question. From a psychosexual point of view, one could argue that teenage boys are experiencing the junction between cutting their ties to the primary female in their life (their mother) and experiencing sexual feelings for the first time towards another woman. Thus an older woman can fulfil both their need for a caring, maternal relationship and a sexual relationship. That someone could fulfil both roles could manifest as a strong sexual attraction in a young males. I'm sure Freud would having something to say about that. Rockpocket08:05, 18 June 2006 (UTC)[reply]
Maybe I'm misremembering my youth, but I seem to recall that teenage boys lust after anything with two legs and a pulse. That said, Rockpocket is probably on to something with his reference to Freud. There are also undoubtedly teenage boys who find that most girls their own age are immature, just like (many more) teenage girls find boys their own age immature. --Robert Merkel11:37, 18 June 2006 (UTC)[reply]
Well, make a decision. Do you think that or do you not?Ā ;) My opinion more or less echoes theirs, without the Freudian part. Evolution probably has little to do with it. Black Carrot21:48, 18 June 2006 (UTC)[reply]
On the question of evolution, it may have something to do with the female reproductive peak much later in life (I think 35yrs. is typically cited,) so perhaps the male evolutionary response is to seek out those females most likely to bear children?
The thing about the sexual peak at 35 doesn't jive with evolutionary/reproductive success theories, because women begin to lose fertility in their late 20s or early 30s. A much more documented phenomenon is of older men seeking out women in their early 20s, because these women are more fertile. At 35, the risk is much higher for pregnancy complications and birth defects. My pet ideas:
1) When (straight) teenage boys first become attracted to women, some of them might find themselves more attracted to "unobtainable women" such as celebrities, models, and older women, because there isn't any real chance of having to interact with them. They can avoid the fear of being rejected or humiliated, because they're obviously not going to hit on (or get hit on by) their friend's mom.
2) Teenage girls are just as nervous/self-conscious as teenage boys, while older women are generally much more confident and comfortable with their sexuality. Confidence is a huge turn-on for most people. TheSPY15:07, 19 June 2006 (UTC)[reply]
Some people are weird, some people like older partners, some younger, some much younger, some too young, but those people go to jail. PhilcTECI22:23, 20 June 2006 (UTC)[reply]
Diffusion and Osmosis
What does "concentration gradient" and "chemical potential" mean in the context of diffusion?
I am often confused by the idea of "diffusion". THe following is my idea of what's diffusion?
"The dispersion of random moving particles from high concentration to low concentration"
For the definition of osmosis:
"The diffusion of water from low concentration to high concentration"
Please correct any wrong ideas thank you!
Concentration gradient is the rate of change in the concentration of a substance along a given direction. In the context of diffusion, say you have a region of high concentration of a substance and a region of low concentration of the substance. As you move from the region of high concentration to the region of low concentration, the concentration changes gradually. Concentration gradient in this context is a measure of how rapidly the concentration changes as you move from one region to another.
In osmosis, you have one or more dissolved substances (solutes) dissolved in a solvent (of which water is a common example). Osmosis is the diffusion of solvent across a semi-permeable barrier from a region of low solute concentration to a region of high solute concentration. Osmoisis is a form of diffusion. (In the definition of osmosis you gave, "concentration" is that of the solute(s), NOT of the solvent)--72.78.101.6112:52, 18 June 2006 (UTC)[reply]
Why does the particles MUST move from high to low concentraiton?
The net movement of particles from a region of high concentration to a region of low concentration is the result of the movement of many individual particles. For simplicity, imagine that there is a (real or imaginary) boundary separating the two regions and assume that particles are equally free to cross the boundary in either direction. In order for a particle to cross from side A of the boundary to side B, there first needs to be a particle on side A (near the boundary). If there's a higher concentration of particles on side A (than side B), probability dictates that the expected number of crossings from side A to side B is higher than in the reverse direction. Note that the net flow of particles is a statistical average. Particles cross the boundary in both directions. It's just that there are more crossings in one direction than in the other.--72.78.101.6114:50, 18 June 2006 (UTC)[reply]
They don't have to, its perfectly possible that they don't atoms molecules are constantly moving about, they go wherever, but it is more likely that they will go to a lower concentration. PhilcTECI22:21, 20 June 2006 (UTC)[reply]
Case in e-mail addresses
I've looked at the e-mail address article, but it doesn't seem to be clear on whether upper-case and lower-case letters are treated as different characters in e-mail addresses. Either they are or someone doesn't want to talk to me- which is it? HenryFlower08:16, 18 June 2006 (UTC)[reply]
It depends on the software which receives and routes the e-mail. There are many different software solutions for this, and some will distinguish between upper and lower case in addresses. However, upper and lower case unaccented Latin characters should not be significant in the domain name (that is, the part after the @ sign) according to the rules of DNS; however it remains possible that some e-mail software will still care. For this reason, best practice in reproducing an e-mail address is to use exactly the case originally given. Notinasnaid08:32, 18 June 2006 (UTC)[reply]
Also, some web-based email services like Gmail and Hotmail force all usernames to be lower-case, which helps. But with email addresses residing with ISPs, their policies all vary. -- Daverocks (talk) 12:35, 18 June 2006 (UTC)[reply]
1.What are the functions of drugs?
2.What are the helpful and harmful benefits of drugs to people?
Try the article on drugs and the articles on medication and recreational drugs linked therein. Also google is your friend. After doing some research on your own please ask specific questions on anything you can't find on Wikipeda and the net. Weregerbil11:23, 18 June 2006 (UTC)[reply]
I'd say they all make you better if you take the right amount, and make you sick if you take the wrong amount. In some cases the right amount would be "none", but in the words of ... hell, I don't even know ... "Of course too much is bad for you - that's what too much means!" Confusing Manifestation09:30, 19 June 2006 (UTC)[reply]
Turkish spider
Does anyone know what kind of spider this is? I took these pictures in southern Turkey, near the village of Aglasun. Many thanks, pjd11:50, 18 June 2006 (UTC)[reply]
Many thanks Kjoonlee, I just read the article and you are probably right. The eyes on top of the head, the pincer 'jaws' and the long pedipalps 'giving the appearance of two extra legs' all point to a windscorpion. pjd14:20, 18 June 2006 (UTC)[reply]
Some varieties of potato produce seed, some don't. The ones that do can be grown from seed. It's just that they germinate slowly, the plant grows smaller, and produces less harvest than potatos grown from tubers (the tuber has all that easy-to-use energy that gives young plants a jump start on life.) So commercial production starts from tubers. Potatos are occasionally grown from seed by researchers when they try to produce new varieties by cross pollination. Weregerbil13:07, 18 June 2006 (UTC)[reply]
Non-microwavable security devices
OK, so i've just been to the supermarket and bought some razor blades. They come fully equipped with a sticker saying: "This product contains a non-microwavable security device". Presumably this is some kind of RFID tag. My questions are:
1) Is a RFID tag any more or less microwavable than a razor blade? The razor blades don't come with a 'Don't put me in the microwave' warning.
2) Why would you want to microwave a packet of razor blades anyway (unless you were into making sparks?)
Presumably that's a safety warning against attempts to destroy any RFID tags embedded in the product by "cooking" the product in a microwave.---72.78.101.6113:09, 18 June 2006 (UTC)[reply]
I think the point of the warning is that you should not microwave it, not that microwaving would have no effect. Hence not a dare, but a warning of possible sparksāi.e., this packaging contains hidden metal. āBradley23:29, 19 June 2006 (UTC)[reply]
They've actually covered this in the Feedback column of the New Scientist - why would you want to microwave razor blades!? Or an RFID tag, for that matter? --Jrothwell16:39, 20 June 2006 (UTC)[reply]
Firefox problem
Hello. I am trying to download Google's notebook, and I keep getting this darn porblem about it not letting me install the software. Then, below the address bar, it sasys "Software installation is currently disables. Click Edit Options... to enable it and try again." I then added "tools.google.com" to the allow list, but it still doesn't let me download it. I followed all of the instructions on the page that helps you, but to no avail. Any ideas? Thanks a lot. Iolakana|(talk)16:22, 18 June 2006 (UTC)[reply]
it's unlikely, but could be a profile problem. Try removing your Firefox profile and starting again (it'll remove all your cache/bookmarks, though). Heres how; Close all Firefox windows and make sure the firefox process is stopped. Assuming you're using windows go Start -> Run "Firefox.exe -Profilemanager" (if you're not running Windows you can use the same option through command etc), delete your current profile, then create a new one, then restart Firefox. There's a chance that might fix it as it could be due to some mismatching. I suggest you try this as a last resort only though. -Benbread21:55, 18 June 2006 (UTC)[reply]
Why do scientists write reviews and how long does it take?
What types of reviews are you talking about? Book reviews, article reviews, peer review? (Movie reviews?) The one type of review which is most associated with scientists is the peer review, take a look at our article on that. As for how long it takes, surely it depends on the subject matter and the scientist. --Fastfission18:22, 18 June 2006 (UTC)[reply]
In my mind the sort of review most associated with scientists is a review article. Research articles describe results from a particular experiment or a set of experiments. Review articles, on the other hand, describe the results from a set of research articles, attempting to unify various results with a simpler explanation, usually trying to argue that the various results support the author's personal theories. How long it takes depends on a lot of things: how well the author knows the literature, the intended length of the review/amoung of content to be included, number of authors writing the review, number of hours per day spent writing, etc, so it's hard to give a good answer. Hope that helps. 128.197.81.18118:39, 18 June 2006 (UTC)[reply]
I'm pretty sure whomever is funding the person's work is funding any review articles the scientist writes as well. Unlike actual experiments which can require specific funding for equipment, lab workers, chemicals, etc., writing a review paper really only requires time, so there isn't really a need to request extra funding. 65.96.221.10722:59, 18 June 2006 (UTC)[reply]
I have written a number of reviews in my time and, in my experience, they can take anything from 10 hours to 50 hours of work depending on length and how much i know about the relevent primary literature off hand. I often get a student or post-doc to write a draft first, so that cuts down on my time. In most cases there is no payment for writing the review (though occasionally there may be a token fee paid if it is an invited review) so my time is paid for off research or core grants. Though, as is the case with most scientists, grant, review and paper writing tends to happen on your own time (at weekends and evenings). Rockpocket02:49, 19 June 2006 (UTC)[reply]
Scientific reviewers are almost always benevolent, unpaid. It's considered 'part of the job': you review papers for others, and expect others to return the favor, although this is done anonymously, so you never know who comments on your own work. In addition to the factors already listed, the total time it takes to get the reviews back also depends on the willingness of the Editor responsible for the publication to chase reviewers, on the professionalism of the reviewer(s), on the efficiency of the secretarial assistants, etc. Sometimes, the preparation of a special issue on a particular topic may lead to further delays in the review process if the Editor insists in synchronizing the handling of a number of papers, or if multiple papers are sent to the same reviewer(s). For the most responsive journals, you may expect to hear about your paper in a matter of one to a few months. In the worst cases, you may have to wait for a year or more. --Michel M Verstraete23:37, 19 June 2006 (UTC)[reply]
CSS DIV issue
I've been trying to make a workmanlike image map using primarily CSS. After scouring Google for examples of how to do this, I've ended up with what seems to be a relatively basic approach. It almost works...
Basically, I have a menu image with a number of places to click on little links to other pages. The basic CSS behind it is as follows:
Pretty straightforward, yes? (I know it would be more straightforward if the positions were "absolute" but that doesn't work with the arrangement I have). The little red borders are just there so I can see where the links are set for at the moment.
Now this all comes up perfectly on the screen. The menu image is there, the links are in the right place, they do what they are supposed to do.
Except that the entire menu image itself is also a link, and goes to wherever the first button is set to go. This is not what I want it to do, nor is it what it seems to me that it should do (I haven't told the entire headermenu to be a link, just the div inside it... right?).
What could be causing this? It happens in all browsers I try it on. I find it perplexing because I can't see why it thinks it should do this, much less how to prevent it from doing it. --Fastfission18:31, 18 June 2006 (UTC)[reply]
The HTML 4.01 Transitional DTD says: <!ELEMENT A - - (%inline;)* -(A) -- anchor --> I don't think you're allowed to put <div> inside <a>, because <div> is a block-level element, not an inline-level element. --Kjoonlee18:54, 18 June 2006 (UTC)[reply]
Turning the <div class="aboutbtn"> into <span class="aboutbtn"> made it so that the links don't appear at all.Ā :-( CSS sometimes makes me sad... --Fastfission19:02, 18 June 2006 (UTC)[reply]
Well, I could try that as a last resort, but it's not at all what I'm trying to do (I was trying to make an imagemap, i.e. links positioned in regions on an image)... --Fastfission13:56, 19 June 2006 (UTC)[reply]
Here's something else that drives me bonkers. If I use SPAN and make the positions ABSOLUTE, then it works. However it won't (unsurprisingly) stay "glued" to the menu image (If I resize the window, they are not in sync at all). If I make the positions RELATIVE then the links don't show up at all. What the heck? --Fastfission14:37, 19 June 2006 (UTC)[reply]
OK, I got it to work with the original code, more or less. A lot of my troubles were stemming from the fact that I termined by curly bracket on the line before the CSS posted here with a semicolon (habit), which apparently made all hell break loose. But once I removed that semicolon, it works fine. Sigh... --Fastfission15:08, 19 June 2006 (UTC)[reply]
Blade Sharpening
In the film 'the colour purple', there is a lady that sharpens a razor on what appears to be a leather strap. How is a leather strap able to sharpen a metal razor and is this method still applicable to modern-day blades? --Username132 (talk) 20:54, 18 June 2006 (UTC)[reply]
As I understand it (i.e., in my limited understanding), strops aren't very good at sharpening, but they're good enough that it can stretch out the time needed between "real" sharpenings. If you think of the use of a razor, the thinnest parts have a tendency to "fold over" back in the opposite direction of the razor's use. This "folding over" makes the edge less keen. A few strokes on the strop helps reverse this and tide you over until the razor can be resharpened with a more efficient tool. - Nunh-huh 23:48, 18 June 2006 (UTC) Leather strops are used with an abrasive polish (absorbed by the leather). - Nunh-huh03:29, 19 June 2006 (UTC)[reply]
I don't remember that part of the movie (i barely remember seeing it at all.) But, any good Boy Scout knows that an essential part of knife sharpening (for wood carving purposes, at least) is use of a 'slipstick' which is essentially a piece of leather bound to a small plank of wood. It is used after the knife has been sharpened on a stone, to break away the fine edge on the blade left from the stone.
Static On My Person
If my skin is non-conductive at low voltages then how does touching an earthed object with one hand remove static from my entire body? --Username132 (talk) 22:18, 18 June 2006 (UTC)[reply]
For one thing, "static" is the same as high voltage. Second, your skin isn't non-conductive. Instead, skin is both a bad insulator 'and' a bad conductor. It's full of moisture, particularly salt water, and is backed up by very wet and salty meat. In other words, it's a resistor. Touch your finger to the leads of an ohmmeter, and you'll see a reading somewhere between thousands of ohms and hundreds of thousand of ohms. If your skin was made of metal, then it would only take a few nanoseconds in order to discharge your entire body by touching Ground. Instead it takes many microseconds: it's still almost "instant," yet it's much slower than what metal would do. --Wjbeaty22:32, 18 June 2006 (UTC)[reply]
So what sort of features of a person would mean they would have a very high/very low resistance? I have a friend who can literally touch one finger to a wire and then touch another finger (on his other hand) to the other and of a wire and be able to complete the circuit, on voltages < 9v! We call him the human wire... -Benbread22:42, 18 June 2006 (UTC)[reply]
I am a person with a low (electrical) resistance. This is becasue I sweat profusely on the palms (and feet). When I touch the leads of the ohmmeter, I registered the lowest resistance in my class (I don't remember how much). Even though I don't sweat all over my body, I suppose that the sweat on my palms makes a very good contact with the leads, thus allowing electric current to pass easily. The worst part was that I frequently got small electric shocks from the bare wires of the 5V circuits we used to build in our electronics labs. I even used to feel the tingle if I put my fingers across a conducting diode (~ 0.7V). It is a different issue that many of my friends didn't believe me. -- Wikicheng04:14, 19 June 2006 (UTC)[reply]
This is the same thing the E-meter does in Scientology. The conduction at the surface, i.e. how much you're sweating, is very important in the total resistance, which is how the E-meter does a good job of measuring stress. (or engrams I guess, depending on your beliefs). I believe one of the measurements of a polygraph may operate on a similar principle. moink07:18, 19 June 2006 (UTC)[reply]
Please help me identify this insect
Unknown insect
I found this very odd insect in my parents house, they live on the north south end of Vancouver Island in Sidney, British Columbia.
I have never seen such an insect around here before and was wondering if anybody could identify it. It is about 1 inch long and was sitting high on a wall near the ceiling. HighInBC23:42, 18 June 2006 (UTC)[reply]
Just as an aside, Sidney is nowhere near the North end of Vancouver Island. It's at the North tip of a small peninsula near the South of the island. moink07:15, 19 June 2006 (UTC)[reply]
Um, I think "arrowroot flour" simply means flour made from arrowroot, not arrowroot mixed with wheat or whatever. So I'd say 100:0. Depends what you want to use it for, though. āKeenan Pepper03:08, 19 June 2006 (UTC)[reply]
Is the Wikipedia being censored by the academic guild?
This may seem like a rare problem but I have noticed that some scientific and technical articles are being edited to prevent other users from obtaining a complete and full comprehension of a topic in the same manner as a member of a trade or artisan guild might try to hide techniques or methods or understanding of what the topic actually involves. Such articles are only permitted to have a highly technical version or explanation of the process being presented in the same manner as a tradesman or artisan might withhold simple explanations from a patron for the sole purpose of mystifying the topic and keeping the patron from knowing ātoo much.ā What is the Wikipedia policy on such behavior where simple and accurate explanations are continuously deleted from an article on the false pretense that the article is not about the example although the example fully clarifies the topic? ...IMHO (Talk) 04:36, 19 June 2006 (UTC)[reply]
Examples?
Yes, I'd like to see an example too. Of course there's a lot of information difficult for "outsiders" to understand in the 'pedia, but generally it's because of the persons lack of concern for readers with a very low level of understanding. Nothing of what I have seen suggests censorship. Ā freshofftheufoĪĪÄæŠĀ 04:59, 19 June 2006 (UTC)[reply]
I would hope not but then suppose all sysops were also members of the telecom brotherhood or union and certain accurate but simplified technical disclosures were routinely deleted? Would this not make you a bit suspicous? As for examples. Put the Half-life article on your watch list and see over a period of time what conclusion you might reach. ...IMHO (Talk) 05:23, 19 June 2006 (UTC)[reply]
I'd say sometimes the medical articles are written in unnecessarily technical language. But I think this is just health professionals failing to consider their audience when writing here rather than a deliberate attempt to obscure. See Hanlon's Razor. There's also the fact that writing both accessibly and accurately about technical is a very difficult skill.
I understand the difficulty for any individual to step far enough away from the field of expertise to see it clearly form a layman's pov but that is why we participate in the Wikipedia in the first place. My concern is that when such experts guard an article with such jealously that any user who is able to bridge the gap between the experts and the layman is prevented from adding simple but accurate explanations. ...IMHO (Talk) 06:30, 19 June 2006 (UTC)[reply]
In this regard you must unfortunately include mathematical symbols and representations which more often than not require examples of computer code and data in order that the jargon be explained. ...IMHO (Talk) 06:33, 19 June 2006 (UTC)[reply]
Perhaps we don't want to sit around and watch the half-life articleādid you choose this article as a pun? Why don't you find an example of an edit that removed factually accurate information that made the article harder to understand? My guess would be that incorrect analogies are removed from articles by people who have a definite understanding of the material and that you are simply paranoid. Also, just because a statement is understandable doesn't mean it is true. āBradley23:16, 19 June 2006 (UTC)[reply]
To have coordinated censorship you'd need coordination among academics in the first place. Which generally does not exist. But as a form of systemic bias, I think it is true that sometimes certain lesser-known topics get monopolized by those who know a lot about them but are not good at explaining it. The better known a topic is, the less likely this can last for long. But there are some articles which reflect a total lack of consideration for the layman (even something as non-technical and narrative-based as our biography of Franz Boas, which is about 3X too long, suffers from this). --Fastfission13:54, 19 June 2006 (UTC)[reply]
I think that in many cases, the technical jargon is used because it saves time--it describes something specific in a way that is easily recognized by people in the field, while using a minimum amount of language. The challenge for Wikipedia, or any widely-used reference source, is how satisfy both "expert" users as well as the public at large. Experts don't want to plod through simplified explanations of what they already know; novices don't want to be frustrated by language they don't understand.
Going back to your question, I believe that there's a policy or guideline or something about how Wikipedia editors should not act as if they "own" a given article. Wikipedia is about reaching consensus and allowing many people to do their bit towards improving an article. --Tachikoma14:06, 19 June 2006 (UTC)[reply]
The problem with reaching consensus is that there is a small group of committed academics who jealously guards some articles, immediately removing any attempt to make them accessible to the general public (which, while far more numerous, lacks the same level of commitment and is thus easily scared off by such actions). The only way I was able to find around this problem was to create a separate article for laymen. For example, the article Boolean algebra suffered from this problem, so I created the simplified version as Boolean logic, and added dabs at the top of each, pointing to the other. StuRat17:11, 19 June 2006 (UTC)[reply]
Yes this possible solution occurred to me as well so I did the same thing and avoided even the temptation of putting a link to the new article in the existing article's "See also" section. Perhaps this way the new article will not be found and deleted before it has gained a few edits from other users who can help fight those who are unsympathetic with the needs of the layman and sometimes experts alike The real scare is that the person standing guard over the article I am concerned about has a false concept of the subject matter. Perhaps it is just as well that a new article be created to give everyone an opportunity to know the truth about the topic. ...IMHO (Talk) 19:43, 19 June 2006 (UTC)[reply]
ādragging discussion back a few indentsā
Please, please, please don't just create your own fork of an article and try to hide it away somewhere. For one thing, it's very inefficient. Editors may contribute to one branch or the other, allowing both versions to be incomplete. For another, it's frustrating to our readersāthey've only got a 50/50 shot of hitting the 'right' article. Finally, it's an ultimately futile effort. Eventually someone will notice the duplication and merge the two articles anyway.
There are several strategies for dealing with an article that you believe is overly technical.
Open a discussion on the article's talk page, and invite participation from the article's regular editor(s).
If an article contains many technical subtopics, it may be appropriate to rewrite it in summary style. (Create a main article with short, accessible descriptions of each subtopic, and link appropriately to technical subarticles.)
Seek comment from other editors using a request for comment. We can't help to resolve your dispute if you don't even tell us what article you're talking about.
Finally ā and most importantly ā assume good faith on the part of your fellow editors. Accusing other editors of censorship, or of deliberately concealing information on behalf of some mysterious guild, tends to taint the working relationship a bit. Communication through text alone can be difficult and ambiguous. Other editors might interpret your attempts to make the article more accessible as sloppy or imprecise and be unaware of their own article ownership issues. They might feel attacked by your implications that they are censoring material or trying to hide information.
So do we at least get a hint about what article(s) you're talking about? We can't help you fix things if you won't tell us what the problem is. :D TenOfAllTrades(talk) 00:09, 20 June 2006 (UTC)[reply]
Hi! The following question is a product of my 'momentary inattentiveness' in class(please don't avoid answering for punishing me).
What is the first 'patented form of life'? I'm quite sure, I heard the name of a scientist- Ananda Mohan Chakrabarty, in this connection(though I doubt its authenticity).
How far Super Bug is related to this? Thanks,--Pupunwiki07:51, 19 June 2006 (UTC)[reply]
hi!
The first "patented form of life" was invented by the scientist CHAKRABARTY which are nothing but the OIL EATING BACTERIA....
Oil Eating Bacteria are chiefly used to clear oil spills in the process of BIOREMEDIATION
In the year 1980 Chakrabarty discovered a bacteria[SUPERBUG] that could digest crude oil.
SUPER BUG is said to be a strain of bacteria that is resistant to all antibiotics.
It is also said to be a strain that is accidentally imported into florida from the Middle East then spread to California where it is a very serious pest feeding on almost all vegetable crops and poinsettias
eg;- Bemisia tabaci, poinsettia strain
some oil eating bacteria are also resistant to antibiotics...in this way super bugs are related to oil eating bacteria
The oil eating bacteria Pseudomonas species is one such example for a super bug[resistant to antibiotics]
--hima 10:27, 19 June 2006 (UTC)
well, i was surfing the "war portal" on wikipedia recently. One of the articles had this linkĀ : "http://uncyclopedia.org/wiki/Palestine", under its "external links" section. And i was shocked to visit the link and the contents. And i think that site itself is open for editing, but the content still is shocking. And they have not even deleted it. Can someone help?
Uncyclopedia is in no way affiliated with Wikipedia, the site looks similar beacause they use the same software (and because they are a conscious parody site of Wikipedia). We have no influence on the content of articles on uncyclopedia, if you think their Palestine article is crossing the line of good taste, it's best to take your concerns there. Now, whether or not an external link to an uncyclopedia article is appropriate for a Wikipedia article is another matter...where did you find the link? -- FerkelparadeĻ10:04, 19 June 2006 (UTC)[reply]
I read somewhere (maybe in the uncyclopedia) that it was purchased by Wikimedia. Since you can't edit articles who writes them? ...IMHO (Talk) 13:59, 19 June 2006 (UTC)[reply]
Uncyclopedia uses MediaWiki software, like Wikipedia. They are not "owned" by the same people. You can edit articles there, just like here - anyone can. What the above poster meant is that the editors here are not responsible for content there, as the majority of users do not overlap between the two sites. -Goldomā½ā½ā½ā14:32, 19 June 2006 (UTC)[reply]
Well you can edit some things but not the majority of things in line with the idea of a contra-wiki. If you could edit everyting then it might actually serve the role of a parody where Wikipedia users could vent steam but as is its more like a spoof than a parody. ...IMHO (Talk) 19:33, 19 June 2006 (UTC)[reply]
I was thinking in terms of an electron though I imagine the specific case is unimportant - my question is - Is there any reasoning or justification behind this relationship, (it seems to be a theorectical assumption used in a model) - and additionally, who originally came up with this idea and are they still alive and sufficiently sentient to be asked how/why they came up with this relationship?HappyVR14:19, 19 June 2006 (UTC)[reply]
(disclaimer: not a physicist) Could you maybe clarify the question? Are you asking why is the complex square not simply a part of the wavefunction so that it evaluates directly to a probability? If so, this is far from a perfect answer, but it is one perspective: consider variance and standard deviation from statistics. Mathematically, variance is the simpler value, in a sense, but its units aren't the same as the original data, they are the square of those units, so the standard deviation is often used, which is simply the square root of the variance, and thus in the same units as the data. Now I'm not saying that's the real answer to your question, I'm just saying sometimes the mathematically easy quantity and the intuitively simple quantity are not the same. A better answer might be that photons/electrons/etc act like complex numbers in a sense (i.e. they follow the same rules when looked at in the right light) and it works out that once you have the complex "amplitude" for an event worked out you can square it and find the actual probability for that event. But perhaps I've only restated your question and added nothing... 128.197.81.18118:56, 19 June 2006 (UTC)[reply]
Well - I'll try to clarify(using electrons) - within the theory, the wavefunction is a property of (an electron), physical properties can be calculated using functions operating on the wavefunction. (A bit like we could have a function describing my velocity at a given time and you could use that function to calculate how far I've gone etc). In this case the probabilty density (thats how likely it is for an electron to be found in a given region - a bit like gas density) is calculated using the complex square of the wave function - thus if the wavefunction is complex eg a+ib the propability density is (a+ib)(a-ib). I was wondering why this function - what reason - why not (for instance) the magnitude of the complex number, or indeed any other function? Whats the reason or reasoning behind it?HappyVR09:14, 20 June 2006 (UTC)[reply]
I have one answer now (Max Born developed this), however maybe a physicist could explain (maybe they have read Borns papers) why this relationship was chosen - is it just for simplicity - I can't see any reason why this relationship has to be right (eg units) - as possible alternatives I could suggest (using a+ib to represent a complex number) the magnitdue sqrt (a^2+b^2) or the square of the magnitude (aa+bb) as two of many possibilities as alternatives to the complex square (aa-bb) being the right answer. Can anyone explain any reason to believe that the complex square should be used as a measure of the probability density.HappyVR08:35, 20 June 2006 (UTC)[reply]
Wavefunctions are a mathematical construction. They provide a convenient mechanism for describing the relationships which ultimately give rise to quantum mechanical observables, but they need not have any tangible meaning themselves and are never directly measured. In fact, you don't need wavefunctions to describe quantum mechanics. Matrix mechanics and mathematical formulation of quantum mechanics describe a number of alternative mathematical formulations that give rise to the same observables and hence must be equally valid descriptions of quantum mechanics. However, for many practical applications, wavefunctions are the easiest approach. In this sense, asking why should (note, not aa-bb, as you suggest) be a probability density isn't really a sensible question. If it wasn't a probability density then it wouldn't be useful and we would be using some other formalism. However, asking what it means that this relationship holds for the intrepretation of quantum mechanics is an interesting question. In the simplistic way of thinking about things, it means that every particle describable by quantum mechanics can be equated to a wave that has not only an amplitude but also an orientation in space (e.g. a direction in the complex plane) and that determining the interactions between waves depends on considering these oreintations, but ultimately after considering any interactions it is the magnitude, the resulting a*a+b*b, that gives rise to the observable states. Dragons flight09:13, 20 June 2006 (UTC)[reply]
oops - yes bit of a bodge up by me with the 'complex square' - however what I was asking was basically what about sqrt(aa+bb) - (in a simple sense eg addition of vectors this seems to make more sense.HappyVR10:35, 20 June 2006 (UTC)[reply]
Or to put it much simpler - is there someway of showing that using (for instance) |sqrt(aa+bb)| as probability density is wrong?HappyVR
Appropriate Waste Disposal
I have an old computer that I failed to fix. I've salvaged some components but I don't know if the motherboard works properly. It used to run on a 112 W PSU and has no AGP slots (just three PCI and some weird stubby slot). Should I just chuck the mobo and processor in the electrical waste at the tip? Should I keep the processor or PSU? What should I do with the case? Can't it be melted and used in something? There aren't enough provisions for people who want to be environmentally friendly... --Username132 (talk) 14:27, 19 June 2006 (UTC)[reply]
You are correct that computer parts may contain nasty stuff that you don't want ending up in landfill. The best bet is to contant your local recycling company and ask if they have a place to take it. (If your city picks up recycling, ask them, or if not, just another local company). Places like Office Depot often take in things like used-up rechargable batteries for recycling, but I doubt they'd have room to take whole MBs. -Goldomā½ā½ā½ā14:36, 19 June 2006 (UTC)[reply]
The plastic case is probably just that plastic plus some filler - maybe you could put that in any plastic recycling bin you can find. The processor is mostly inert - might contain some gold though but not much - the case will be ceramic or a resin. As far as I know its the glass fibre and the resins gluing it together and the lead used in soldering on the motherboard that are supposed to contain the nasties - no idea what you are supposed to do with this though - burning it is the way to release the chemicals enviromentalist don't like. The PSU contains sufficient scrap metal to be worth at least 50p to a scrap metal merchant - that's most of what I can say to help. (Art project is good idea - maybe you could use the processor as a coaster for small tots of rum)HappyVR14:38, 19 June 2006 (UTC)[reply]
Why wait for a homeless person? I bet one of your friends would like a hunk of junk. I sort of would, but I'd like it to be in slightly better condition. --M1ss1ontomars2k4(T | C | @)04:55, 20 June 2006 (UTC)[reply]
Can medium format (120) film be developed by my local pharmacy?
No. It is likely that your local drugstore sends all film to a processing service. It is probably easiest if you just call or visit the drugstore to ask; however you might be better served by searching for a nearby camera store (not a chain like Ritz or its siblings) and asking them for advice. --LarryMac16:11, 19 June 2006 (UTC)[reply]
Right.......and you think getting stuff to an external service and back would allow a 1 hour turnaround? that would be some pretty impressive logistics. Plugwash01:00, 20 June 2006 (UTC)[reply]
Where did anybody ask for 1 hour turnaround? I should have added that many stores do now have the self-contained machines that allow processing of 35MM C-41 process film on premises, but 120 is a whole different animal. --LarryMac01:03, 20 June 2006 (UTC)[reply]
The Moon
From what points on the Earth does the moon apear largest?
Thanks, Lucy Hallam
The Moon would be closest to an Earth-bound observer on Mount Everest, but that's only a 9 km difference versus a sea-level observer. By comparison, the Moon's orbit causes it to vary in distance from the Earth by 40,000 km. So actual size from earth doesn't appreciably vary no matter where you are.
However, there is a well-known Moon illusion where the Moon appears largest near the horizon, though it's simply a trick of the brain's interpretation of the image, not the actual size of the Moon itself. ā Lomn | Talk16:05, 19 June 2006 (UTC)[reply]
Oh yeah. Back to the moon illusion. Due to geometry, shouldn't the moon's actual angular diameter be greatest at the zenith rather than the horizon? --M1ss1ontomars2k4(T | C | @)04:54, 20 June 2006 (UTC)[reply]
Yes. Moon illusion says "The true angular diameter of the Moon is about 1.5% smaller when it is near the horizon than when it is high in the sky, because it is further away by up to one Earth radius." -- Wikicheng05:58, 20 June 2006 (UTC)[reply]
Fish question
What is the name of this fish? It lives deep in the ocean where there is no light. It has an extendor over its eyes that has a bulbuous attachment that glows. It was used in Disney's movie Nemo.
TOTAL COST PER APOLLO MISSION:
-----------------------------
Year ($M) (94$M)
Apollo 7 1968 $145 $575
Apollo 8 1968 $310 $1,230
Apollo 9 1969 $340 $1,303
Apollo 10 1969 $350 $1,341
Apollo 11 1969 $355 $1,360
Apollo 12 1970 $375 $1,389
Apollo 13 1970 $375 $1,389
Apollo 14 1971 $400 $1,421
Apollo 15 1971 $445 $1,581
Apollo 16 1972 $445 $1,519
Apollo 17 1972 $450 $1,536
---------------------------------
$3,990 $14,644
The data show that over the entire lifetime of the the space shuttle program the cost has been $145 billion, and about $112 billion since the program became operational.
Furthermore, the average cost per flight has been about $1.3 billion over the life of the program and about $750 million over its most recent five years of operations.
Not to get OT, but take into consideration the expanded capability of the STS, in crew capacity, flight duration, and payload. Not to say that $1.3B to gas up a ship and send it around the earth seems cheap, but...
Many cucurbits have edible leaves, but I have not been able to satisfy myself about Cucumis melo. I was surprised at how little information I could find for such a well-studied plant. BioNatural claims that the Pedi and the Sukuma people eat the leaves as a "potherb and relish", but the mention is off-hand and undetailed, and the company sells herbal extracts, so they may have a profit motive in giving this information. An agricultural researcher in Uganda lists the leaf among the plant's edible parts, but again no detail is given. Cucumis melo is not on Leaf for Life's very long list of plant species that have reportedly been eaten by people. Plants for a future reports that "the sprouting seed produces a toxic substance in its embryo", but not what the toxic substance is, where in the plant it is distributed, nor how long it persists as the plant grows.
What is the name of the device that nullifies the effect of an electromagnetic pulse on electronic devices? It resembles a cage made of wire. I tried a number of searches under different topics and come up empty. It's driving me crazy. āThe preceding unsigned comment was added by 72.54.24.94 (talk ā¢ contribs) 19:39, 19 June 2006 UTC.
I have a group of jpg images which were scanned into the computer under Windows 98 using an HP Scanjet IIcx flatbed scanner. The images seem to be okay except that their widths have been compressed to about 1/3 of the left side of the page with the remainder of the page being solid black. I have never seen this before. Does anyone know what caused this and more importantly how to restore the width of the image without loss of information? Thanks. ...IMHO (Talk) 19:04, 19 June 2006 (UTC)[reply]
I guess one question that has to be asked is what did you do with them? Were they copied to a diskette or CD and were they fine when you first scanned them? I've have some problems with scanners before where no matter how many times I scan the same image, it always scans half the image wrong, and I usually assume it to be a scanner problem. If you've used storage media on the images though it might be a different problem, and there are jpeg rebuilders that may be able to fix them. Oh, and for the record, the blank area of the image is usually called the "canvas". Ā freshofftheufoĪĪÄæŠĀ 00:20, 20 June 2006 (UTC)[reply]
Right the programs I have to view and edit call the whole area the canvas but I can't find the one at the moment that actually allows the image on the canvas to be streched by default rather than moved across the canvas. This is the one I had planned to use to restore the images but I am curious as to the cause. The images were fine after scanning and were only transferred from a FAT32 drive to a NTFS drive over a local Ethernet and have been there ever since. ...IMHO (Talk) 08:58, 20 June 2006 (UTC)[reply]
Ah, I see what you're getting at now. Any program like Photoshop lets you fiddle with the canvas and size settings, but as you know that's not going to leave you with the same detail as the original 1:1 images. It's not likely that the full quality image is still preserved in the file unless they've been somehow vectorized. Sorry, I can't think of why they would suddenly be compressed like that, since they obviously haven't been simply corrupted. Ā freshofftheufoĪĪÄæŠĀ 10:21, 20 June 2006 (UTC)[reply]
By looking in the subdirectory (I was only looking at the results of a search for jpg files)the reason for the problem may now be revealed although I still do not understand what caused the problems. The image name ends with ....tif.jpg so it looks like they were tif images that got saved as jpg images but that still does not indicate how they were distorted in this manner. After removing the jpg extension the thumbnail image does not change and there is no effect on the edit views of the image as if the extension has been ignored and file type determined by some other means. Anyway I suspect some kind of accidental conversion due to file name change and now possibly even a virus. ...IMHO (Talk) 15:22, 20 June 2006 (UTC)[reply]
Orbit/gravity/weightlessness
I have a question relating to gravity/orbits, etc. Do you know who I can direct it to?
I understand that objects/people in orbit around the earth only appear
weightless due to the fact that they are in freefall, and since the spacecraft
and everything/everyone aboard are all falling at the same rate of speed
around the earth (in orbit), they appear to be weightless.
My question is this:
When the astronauts travelled to the moon, they also experienced
weightlessness. Since they left earth orbit on the journey to the moon, and were not in freefall, why were they weightless en route?
Jake Whalen
You should probably check out our article on weightlessness, particularly the discussion on pressure gradients. As a layman, though, here's my attempt:
Weightless freefall isn't dependent on "falling" per se but rather on you and your reference frame (that is, the spacecraft) not resisting gravitational forces, whether or not those forces will eventually cause you to collide with the relevant astronomical body. When you consider "falling" as instead being "coasting without support", weightlessness between the Earth and Moon makes a good bit more sense (to me, at least).
Please note that weightlessness is experienced only when the spacecraft engines are shut-off (free-fall). Any time the engines are on, they exert a force on the craft and its content, and the reaction, e.g., the force exerted by the astronaut on his seat, is the equivalent of a residual weight. --Michel M Verstraete00:04, 20 June 2006 (UTC)[reply]
Adding to Michel's answer: When the engines are turned off, even if the spacecraft is travelling away from earth, it is still 'free fall' because the only force acting on it is the gravity. So you can say that you will experience weightlessness the moment the engines are turned off, whether the spacecraft is moving away or orbiting earth -- Wikicheng06:21, 20 June 2006 (UTC)[reply]
When you throw a ball it is in freefall from the instant it leaves your hand, even though for half of its trajectory it is "falling" upwards. Tiny astronauts inside the ball would experience "weightlessness" - right up until the point when the ball hits the ground and they are squashed by the deceleration. The Vomit Comet does the same thing, only on a bigger scale (and without the hard landing). Gandalf6110:36, 20 June 2006 (UTC)[reply]
The original poster asked a very good question, and it is fundamental to understand it. Everyone's answer was very well written so I can't add much, but one thingĀ : when I was a child they explained meĀ : you are far away from earth, gravity becomes weak.
Well that is simply untrue, in the International Space Station (or Mir) gravity was 9.5 m/s^2 , compared to 9.81 m/s^2 here on earth, I doubt a human would really feel that difference.
The correct answer is simpleĀ : you experience weightlessness when you and your ship have exactly the same forces that work on them.
Evilbu11:07, 20 June 2006 (UTC)[reply]
Just to clarify - it is true that far from the earth the force of gravity due to the earth does become weak; it obeys an inverse square law. Around the distance of the moon, acceleration due to the earth's gravity is less than 0.01 m/s^2. When the astronauts left orbit, they did experience some acceleration due to the ship's rockets, but it was probably pretty small, and once they got far enough out, Earth's gravity became negligible. They were never completely "weightless", but nearly so. --Bmk17:36, 20 June 2006 (UTC)[reply]
Symptoms of long-term oxygen deprivation
What are some possible symptoms of shallow breathing, or mild long-term oxygen deprivation? For instance, someone contracts sleep apnea in conjunction with asthma and allergies, causing generalized shallow breathing and low oxygen intake.
You are actually asking about five sometimes associated, but distinct and independently diagnosable, conditions. Chronic effects, as opposed to acute effects, vary by severity from minimal to marked. At their worst, these conditions can cause some fairly serious effects over time, depending on age and co-morbidities.
asthma: This is usually episodic rather than continual. It usually does not cause hypoxia except in extreme exacerbations. Although it can coincidentally occur in someone with sleep apnea, it is a completely independent condition.
respiratory allergies: The most common of these are simply a stuffy, runny nose, not affecting oxygen level. The most severe kind of respiratory allergy (as distinct from much rarer hypersensitivity reactions) is typically allergen-triggered asthma.
chronic hypoventilation: This can occur from a variety of conditions ranging from genetic defects of breathing drive to congenital brain syndromes to COPD to severe obesity, but not usually from asthma. It typically causes fatigue. In a severe form it can cause chronic hypoxia, and long-term strain on heart leading to cor pulmonale and even death.
sleep apnea: This is most commonly due to upper airway obstruction due to obesity but can have other causes as well. It can cause transient hypoxia during sleep. It can cause daytime fatigue, headache, difficulty concentrating and remembering. There is mounting evidence that obstructive sleep apnea can contribute to the development of insulin resistance and type 2 diabetes.
Since a object on the equator is spinning faster then one on the pole, shouldn't there be a difference in weight between them? Wizrdwarts (T|C|E) 21:19, 19 June 2006 (UTC)[reply]
Thanks for the quick answer! And according to the timestamp on your post, you replied one minute before I even asked! Do you know how much the actual difference would be? Wizrdwarts (T|C|E) 21:37, 19 June 2006 (UTC)[reply]
I've read about the subject, but I have never found a conclusive answer. There must be a major reason, otherwise we would still have both systems. Which reason is that? Afonso Silva21:20, 19 June 2006 (UTC)[reply]
DC power supplies require a power station to be built every fifty miles or so, which becomes very impractical outside large cities. As a result, AC current is used; see the War of Currents article. Andromeda32121:34, 19 June 2006 (UTC)[reply]
Eh, what? There's no problem with transmitting DC over long distances; for long runs high-voltage direct current (HVDC) is actually more efficient than AC. (It has a number of other advantages in certain situations, as well.) AC's major advantage is that its voltage can be easily stepped up and down with a simple transformer, making it possible to transmit current over long distances.
DC transformers are much more complicated and costly than their AC counterparts, rendering them poorly-suited for ubiquitous power grid use. TenOfAllTrades(talk) 22:23, 19 June 2006 (UTC)[reply]
There is really no such thing as a "DC transformer." AC voltage can be stepped up and down with two coils of wire and an optional lump of iron (called a transformer). DC voltages are stepped up and down with relatively complex switches and switching circuits referred to as DC-DC converters or through other more involved or less efficient means (e.g., motor-generator hookups). āBradley22:59, 19 June 2006 (UTC)[reply]
Yeah, DC transformer is a weird thing, as DC keeps the magnetic field constant. Is that it? At least, it is what I learned. The magnetic flux must change in order to induce a current. Afonso Silva23:13, 19 June 2006 (UTC)[reply]
Correct. As stated above, to change DC voltage levels you need converters such as the flyback converter.
As also mentioned above, there are some cases where DC transmission is used over long distances, with much lower losses, one factor that helps it is the fact that AC currents only "run through" thin layer of the conductor increasing resistance, compared to DC current that flows through the whole section of the conductor. VdSV9ā¢ā«01:20, 20 June 2006 (UTC)[reply]
I think it also has to do with safety purposes. I personally had the "oppurtunity" to get electrocuted by AC and DC voltages, and I found that the AC voltage actually pushes your body away so you have a chance of pulling away your hand or the part that is in contact with the circuit. But try pulling your hand from a 220 V DC (thats the common voltage in India) voltage. I think the death rate would be a lot higher if we had used DC voltage.Ā ;-) Jayant,17 Years, India ā¢ contribs11:55, 20 June 2006 (UTC)[reply]
Voltages can easily and cheaply (compared to DC) be stepped up or down using transformers for diferent transmission and distribution needs
Using 3-phase supply allows different voltage levels to be obtained (phase-phase, phase-ground) from the same set of transmission lines
Using 3-phase supply, loads on each phase can be balanced in order to reduce or eliminate the need for a conductor to provide the return path to earth. This means less "conductor per kilometer per megawatt", reducing costs. (This is offset by the phenomenon mentioned above about DC current flowing through the whole conductor whereas AC flows only through a thin surface layer). p.s. where is the wikipedia article on the skin depth effect?
Protection systems in AC circuits are simpler i.e. cheaper because the current passes through a zero every cycle, which can help to extinguish e.g. a short-circuit arc
Disadvantages of AC include:
Line inductance and capacitance to ground may be significant, especially over long distances, causing losses over and above normal resistive losses
Power factor becomes one of the main considerations to system stability and power flow. In particular, attention has to be paid to active and reactive power
It's just a lot more difficult to understand intuitively than DC. You've got all sorts of messy things such as series and shunt capacitors used for various purposes such as voltage boosting, improved power transmission etc.
In conclusion, the reason most systems are AC is because AC is cheaper. As for the electric shock comment, I simply don't think it is correct. An electric current through your body (AC or DC) causes your muscles to contract involuntarily. When someone touches an exposed electric circuit with their hand, muscle contraction prevents them from letting go, which is why when working on an electrical system, workers will (obviously after making sure everything is earthed!) often touch the device/conductor with the BACK of their hand to test for dangerous induced voltages (muscle contraction would then cause their hand to spasm AWAY from the metal). Zunaid12:29, 20 June 2006 (UTC)[reply]
Zunaid gave a great complete answer on the subject. But actually, as for the electric shock, it's much worse in DC, just think of a continuous 220V shock as compared to an intermitent shock. For one thing, the power dissipated by one's body will decrease to 70,7% of the DC, value, not to mention a the reactance of the human body that increases impedance.
That's not true. X volts of AC dissipates exactly the same power as X volts of DC in a given resistance, by definition, because AC voltages in this context are specified in RMS. Furthermore, the peak value of X volts AC is 1.41 X volts, so you would get a 41% worse shock, intermittently, from X volts AC than from X volts DC. The current due to capacitive reactance is negligible, only a few microamps (240 V * 2Ļ * 50 Hz * 100 pF). Inductive reactance would make the current smaller. --Heron21:22, 20 June 2006 (UTC)[reply]
Actually I am thinking more in terms of a device anyone might carry in their pocket similar to a battery powered credit card reader. ...IMHO (Talk) 08:00, 20 June 2006 (UTC)[reply]
Well, the technology certainly exists. You'd basically be doing OCR on a specific location with a roll-through scanner, and that can be done. I don't know that anybody has actually created a product, though. ā Lomn | Talk17:22, 20 June 2006 (UTC)[reply]
Stupid question
In what way is it justifiable to allow stupid people to vote, hold positions of power, etc.? By this I mean logically, as it's obvious that nearly every country's constitution gives them this right, and it is in every way illegal to exclude them of this right. Ā freshofftheufoĪĪÄæŠĀ 04:15, 20 June 2006 (UTC)[reply]
Assuming that "stupid" means they are not able to hold a position of power in a responsible manner, I don't believe they would be voted into that position. Appointed, perhaps. As for voting, I don't see why "stupid" people shouldn't be allowed to vote, unless they do not understand what a vote is or what the voting process means. --M1ss1ontomars2k4(T | C | @)04:48, 20 June 2006 (UTC)[reply]
Of course, "who is stupid" is the core question, avoided or not. Find an objective unambiguous means of defining "stupid" and you've then got a position to argue from (analagous to how many US states deny the right to vote to convicted criminals). Otherwise you've just got a regime masquerading as democracy. ā Lomn | Talk04:52, 20 June 2006 (UTC)[reply]
Intelligence is hardly the only criterion that makes somebody suitable for a leadership position. To take a simple example, the senior staff at Long Term Capital Management were extremely smart people. Didn't stop them losing an enormous pile of money through overconfidence in their own abilities. However, I think I'd expect my elected representatives to have a certain level of intelligence and intellectual curiosity. --Robert Merkel05:09, 20 June 2006 (UTC)[reply]
People are not stupid; they are loyal to their politicians.
People are not gullible; they are ...
In a model two-party democracy, both parties offer capable and wise candidates. Even a moron can vote.
In the real world screwball democracy, ...
Anyway, democracy abhores disfranchising voters. Some countries allow criminals to be disfranchised. Some others are even afraid to do so. Making mistakes now is not the end of the world. There will be future generations to pay for our mistakes. This is democracy. -- Toytoy07:19, 20 June 2006 (UTC)[reply]
Stupid people are idiots. The word idiot is derived from the greek idiotes meaning a private individual who doesn't participate in politics or public life. Given that in the UK almost half the people don't bother to vote, with similar figures in most other democracies, it is the case that stupid people don't vote (we can tell they're stupid because they don't vote). If they're not going to vote anyway it isn't really necessary (& could be counter productive) to actually legally prevent them from voting. AllanHainey08:09, 20 June 2006 (UTC)[reply]
Many smart people do not vote anyway. Why you ask? They know that elected officials are the go-betweens. Go-betweens are the people who represent the bureaucracy to the public and the public to the bureaucracy. For this reason the stupidity or lack thereof among elected officials is virtually nullified. ...IMHO (Talk) 08:08, 20 June 2006 (UTC)[reply]
Depending on who you think are the stupid people, they are possibly the most likely type of people to vote.
Let me try something else: If I set the definition of stupid as a "person who has a low ability to make correct, logical decisions independently in a variety of situations" does that work better? I'm curious about M1ss1ontom's opinion. And as for Lomn's comment, I believe most certainly that it is possible to argue without a position on "stupid", just like you can argue about the existance of God whether you believe or not. You just have to allow some assumptions. Ā freshofftheufoĪĪÄæŠĀ 09:58, 20 June 2006 (UTC)[reply]
It's not whether you believe or not -- I believe some people are stupid -- but whether you can create any meaningful basis for discussion. To use your example, most discussions as to whether God exists understand that they're discussing an omnipotent supernatural being, not just some lame superhero like Aquaman. A useful discussion about God is impractical if one of the parties is instead arguing the existence of his dog.
Therefore, without some standard, all you're asking the ref desk is whether or not we think it's a good idea for you to dictate who votes, and the core point is that when an arbitrary standard is sued to select voters, the actual power lies only with the people who set the standard. ā Lomn | Talk14:23, 20 June 2006 (UTC)[reply]
As an additional note, "stupid" is a particularly vague term. It's possible to debate political vagaries (say, is it right to tax the rich more than the poor) so long as at least an objective comparison is understood -- a rich person makes more money than a poor one, in tax terms -- even if the precise boundaries aren't defined (how much income constitutes "rich"). However, what's the measuring stick for "stupid" vs "smart"? ā Lomn | Talk14:27, 20 June 2006 (UTC)[reply]
Well, I don't know about stupid people, but if you want to exclude particular groups from democracy based on character traits, how about selfish, or lazy, or greedy, or racist, or not policitally correct? Would you rather your representative was stupid or greedy? Stupid or racist? Where does it stop? The particular problem with excluding people from democracy in large numbers is that they are likely to be upset; if you exclude enough you have the potential for unrest or revolution. The general problem in all these cases is making a definition, because in practical terms you couldn't propose a real action or estimate effects until you make a definition of the term. Notinasnaid12:53, 20 June 2006 (UTC)[reply]
Do you see how that's a loaded question suggesting that they shouldn't be, though? Anyway, to try to answer the original question: stupid people should be able to vote because no one has presented a coherent objective case as to why they shouldn't, and modern liberal democracies generally agree that elective rights are restricted primarily by age and citizenship. ā Lomn | Talk17:24, 20 June 2006 (UTC)[reply]
Women decided to prove they were no more idiots in the beginning of the last century. Before, only rich and educated people did vote - as in Athens.
Each time politicians allowed some groups to vote, thet did so because they hoped they would gain more votes than the other party. What if pets and IA machines were allowed to help us choosingĀ ? --DLL20:49, 20 June 2006 (UTC)[reply]
In case you're interested, the kind of government you propose, where intelligence forms a primary criterion for voting/governence, is called a geniocracy. GeeJo(t)ā(c) ā¢Ā 23:00, 20 June 2006 (UTC)[reply]
=Do you suffer from short-term memory loss? - I don't remember
Hi, I've looked at Short term memory, working memory & amnesia but I can't find what I'm looking for. Does anyone know if there is a condition which renders someone unable, or makes it harder to, remember regular or irregularly recurring events once they've happened once. For example something that would make it harder for someone to remember to renew a monthly bus season ticket after she had bought the ticket the first time; or which made it harder to remember to pay regular council tax bills?
I realise that there may not be a name for this other than "forgetfullness" or "disorganised" but if there is a specific condition or conditions which could have this effect could you please let me know.
I hope this doesn't come over as flippant, but it just sounds like a perfectly normal pattern. At least in my experience. The first time you have to pay that bill, it will pray on my mind until it is done. After that, it's impossible for me to hold in my head that it needs doing over and over. What you need is not a better memory, but better organisation. It's hard, and I'm bad at it, but a key thing is not to have lots of places to check: just one master list of things to do. Then you only have to remember to check the list once a week, and have the discipline to both check and act. Notinasnaid10:53, 20 June 2006 (UTC)[reply]
It is named because it was derived from and added features to B. C++ added classes, templates, etc, by Bjerne Stroupguard. (Object oriented, etc). There's no "D" derived from "C", though, to whoever said thait.
Hi,
Its simple but i have this in mind for long time..
In rainy season,in road side some transformer may get burst and the wires get fallen in rain water,so the people who are all walking in settled rain water get shocked.
My question is like the same thing, if some transformer or current giving thing get fallen in sea water,what about the flow of current in the water?Is the whole water get current?If people swim in sea hat happende to them?
They get electrocuted if they touch conducting material or are swimming closely to the source of the shock. But the farther away they are the less likely they are to get a shock because the available current would either spread or go through to the ground. The first would spread it over such a large area it's no longer dangerous, the second would mean it's gone in seconds. - Mgm|(talk)12:48, 20 June 2006 (UTC)[reply]
Another quantum mechanics question
Using the wavefunction derived on Hydrogen-like atom can anyone point me to a page that shows or describes how to calculate (using a quantum mechanical method) the energy of (or energy difference between) quantum states. I was thinking for simplicity of taking the energy when the quantum number (n) tends to infinity as being 'zero' as this seems to approximate totally separate electron and proton. Does this energy correspond to using a semi classical method of using the wavefunction to give propabilty density and using that probabilty density function combined with coloumb potential integrated over all space to give the 'average energy' of a wave-like electron?HappyVR11:46, 20 June 2006 (UTC)[reply]
The purely quantum method is to solve the Schrodinger equation HĪØ = EĀ·ĪØ, where the resulting eigenvaluesE are the energy levels of each orbital. For some reason, we have the solutions for ĪØ but not for E in the hydrogen-like atom article. Instead, the solution for E is in hydrogen atom. Hope that helps, anyway. (And yes, as you can see, as n goes to infinity, you get to zero potential energy.) To be honest, I haven't tried integrating the probability-weighted potential...I suspect that it ought to give you the right total potential energy, and I'd be concerned if it didn't. TenOfAllTrades(talk) 15:15, 20 June 2006 (UTC)[reply]
Cutting animals in half?
Could someone be kind enough to satisfy my curiosity and post a list of animals which can be cut into two (or more) pieces and survive, with each piece growing into a separate creature? Cheers. --Kurt Shaped Box11:54, 20 June 2006 (UTC)[reply]
The story that earthworms can regenerate in such a way they form two worms afterwards is an urban legend as this link and various others show. Given the fact such animals would require duplicate organs, I actually doubt any animals can do this. The living part of some animals can regenerate limbs and/or tails, but the cut-off part will never grow into a full animal itself. - Mgm|(talk)12:44, 20 June 2006 (UTC)[reply]
It is true. The starfish has an extraordinary ability to regererate. But for a chopped-off arm to grow a complete new starfish, the arm must be of sufficient size ā and, as I've heard, the arm should include at least part of the central disc, too. āMysid(t)13:10, 20 June 2006 (UTC)[reply]
Is it possible for a human to fall from a height of about 1-5 stories without injury reliably? I'm getting tired of taking the stairs... --Zemylat13:57, 20 June 2006 (UTC)[reply]
That's quite a range... I would think it has a lot to do with the physical condition of the person as well as what they are landing on. Concrete would be much harder than grass, sand, or gravel. I used to jump from a height of about 12-15 feet when I was a kid to escape being beat up by the bigger kids on the playground (they'd chase me to the top of a slide, I'd jump, that would give me a few seconds to get away) but I doubt I could do it very often now without straining something. Dismas|(talk)14:13, 20 June 2006 (UTC)[reply]
And the ground was designed to be fallen upon. Most buildings have wood or concrete floors covered with linoleum or carpeting and falling on them would be very different from falling on loose sand, rubber, or gravel. Emmett516:24, 20 June 2006 (UTC)[reply]
It happened. I even heard about a parachutist that survived a fall when his chute didn't open. But don't count on it being in any way reliable when it comes to not getting injured. - Mgm|(talk)18:08, 20 June 2006 (UTC)[reply]
So I'd say it depends mostly on the material. The height and state of the person are also very important. I would not risk trying it though. --Proficient22:04, 20 June 2006 (UTC)[reply]
If you use the same setup as stuntmen do, and jump into a giant airbag, then yes, you can jump from that height and survive. It is important to land back first, however, to distribute the force evenly. StuRat00:02, 21 June 2006 (UTC)[reply]
Hairyness and evolution
Male and female primates are both very hairy.
What is the evolutionary reason for female humans being so hairless? What is the evolutionary reason for both sexes sprouting armpit hair, but not knee hair?
Hairy Dweller14:10, 20 June 2006 (UTC)[reply]
For many decades, the most popular explanation of hairlessness was that humans lost their hair to keep cool. Too much hair made humansāvery active apesāhot, like elephants. Elephants evolved huge floppy ears to radiate heat back into their surroundings. But when hominids moved out of the forests and into the savannah, the same task could be carried out by the entire body, thanks to hominids' upright posture (which exposed less skin to the sun) and their lack of hair.
Mark Pagel, at the University of Reading, and Sir Walter Bodmer, at the John Radcliffe Hospital in Oxford, have a new idea. They believe that parasites are the key to human hairlessness. Humans, they say, lost their hair in order to reduce the burden of parasites such as fleas and ticks, some of which would have transmitted disease. Early humans probably lived close together in hunter-gatherer groups, in which the rate of parasite transmission was high. Hairless skin was easier to keep clean. Cultural adaptations, such as the use of fire, shelter and clothing, allowed humans to become furless.
Really interesting, but to be harsh, it actually doesn't answer either of the questions I posed. a) why are women less hairy and b) why do we have armpit hair? --16:08, 20 June 2006 (UTC)
Nice. So women are hairless to appear different. Difficult to imagine an evolutionary mechanism for that though. Hairy 'pits reduce friction? Again, I think it would be difficult to demonstrate a survival advantage there. But as a non-scientist, my understanding of evolution is probably as childish as my sense of humour. --Dweller17:49, 20 June 2006 (UTC)[reply]
For the former, many species have different appearances for genders. For the latter, reducing chafing and irritation would seem a clear (albeit minor) survival advantage. ā Lomn | Talk18:12, 20 June 2006 (UTC)[reply]
Just my 2 cents. Human Females have a layer of fat just under the skin which males normally do not have. This provides a measure of insulation against the cold which means less body hair is needed to keep warm.
Men have fat under their skin, too, although perhaps less than women. When I cut my arm on a piece of glass, I saw the little yellow fat globules myself. StuRat23:58, 20 June 2006 (UTC)[reply]
Very cool answers. Thank you. Still unconvinced, but enjoying the banter. Also, thanks for proving that scientists can answer questions in plain English. Just wish your cousins on the Mathematics page were able to do so. (Mind you, I brought it on myself) --Dweller21:19, 20 June 2006 (UTC)[reply]
Circumcision
I just read the circumcision article, but couldn't find any information on how the "string" that runs on the back of the penis is "dealt with". Isn't the "string" some kind of "tube" for urin and semen? How does one avoid not cutting it off when doing a circumcision? Jack Daw14:46, 20 June 2006 (UTC)[reply]
I think you're talking about the frenulum; it's a band of tissue that runs along the bottom of the foreskin...? It is not involved in the passage of urine or semen; all of that happens in the urethra. the frenulum is frequently trimmed or removed during circumcision without ill effectāit only contains some small blood vessels which heal rapidly. TenOfAllTrades(talk) 15:18, 20 June 2006 (UTC)[reply]
I wonder whether the word "harmless" is appropriate for this procedure. I think that it is more correct to say that the dissection of the frenulum is a normal part of cicumcision, which typically does not produce immediate or long-term physical harm.Tuckerekcut23:44, 20 June 2006 (UTC)[reply]
Texas Instruments subfamily abbreviations
Hi all. I'm trying to figure out what some Texas Instruments IC subfamily abbreviations stand for. For example, I know that LS stands for "Low power Schottky". I want to know what other abbreviations stand for, such as NE, SA and SE (specifically for the 555 timer). Thanks! ~MDD469616:19, 20 June 2006 (UTC)[reply]
Actually, I believe the NE, SA and SE abbreviations belong to Fairchild Semiconductor... but I still have no idea what they mean! Perhaps they're just random.... ~MDD469618:50, 20 June 2006 (UTC)[reply]
Signetics, according to 555 timer IC. Data sheets like this STM one say that those three prefixes refer to different temperature grades. I can't find out why those particular letters were chosen, though. --Heron20:13, 20 June 2006 (UTC)[reply]
Ethanol
Do you have any information on how to make ethanol from paper
When I type the word products in an Outlook e-mail message, pr appears on the first line and oducts jumps to the second line. How can I fix this?Patchouli23:26, 20 June 2006 (UTC)[reply]
It could be an autocorrect problem. Try clicking the 'undo' button right after. If that fixes it (shows products correctly), someone's played a joke on you and added an autororrect to Word, which you can correct in word.--Anchoress23:29, 20 June 2006 (UTC)[reply]
I sent the e-mail. Now when I look at the e-mail in the Sent Items folder, the word products is not disconnected and appears whole.
Bismuth Tellurium Transistors used in water heating/cooling
I just recently heard about a device using bismuth telluride transistors that has the potential to boil/freeze water in seconds from the power of two flashlight batteries. I read this randomly in an old version of the CRC handbook of Chemistry and Physics. I, personally, really enjoy building things, and I would like to add this to my wanted collection, but I do not know where to begin, let alone have the schematic for such a device. I want to ask how should I build this device, and where can I gather the proper information regarding the potential power outputs and details of this machine?
