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December 14
Maxwell's Demon
The concept of Maxwell's demon was proven to not be able to lower entropy because it creates more entropy in the process (see link). What if instead of a demon there was just a small slit? If a high-energy particle happened to slip through, wouldn't that violate entropy? Thanks, Max 216.209.153.14 00:59, 14 December 2005 (UTC)
- Sure, a high-energy particle can slip through. But so can a low energy one. In order for a Maxwell's Demon-type thing to work, there has to be some kind of sorting going on - but I don't see what characteristic a slit has which sorts fast particles from slow ones; it's not as if fast particles are thinner than slow ones. -- Finlay McWalter | Talk 01:14, 14 December 2005 (UTC)
If a very high or low energy particle did happen to slip through first, entropy would be violated, at least temporarily. Additionally, according to quantum physics, higher energy particles have a more concentrated probability field - so they are thinner. Max 216.209.153.14 01:27, 14 December 2005 (UTC)
- The relevant law is the second law of thermodynamics. It is expressed as a tendency, not an absolute law, so the behaviour of the single particle mentioned by Max is not a violation. --Heron 17:33, 14 December 2005 (UTC)
- Also consider: Your particle has gone through the slit. Now there's a greater concentration of high-energy particles on one side, and so there's a greater probability that one of them will go back through the slit to the other side. Statistically, it will even out. --Bob Mellish 17:49, 14 December 2005 (UTC)
What if the change in this particle's state prevented further contact between the two objects? Max 216.209.153.78 22:52, 14 December 2005 (UTC)
- Well, how is the particle's state changing and what mechanism prevents further contact? --Bob Mellish 16:52, 15 December 2005 (UTC)
The higher energy concentration on one side could knock a door closed (There has to be a better example but I can't think of one). Max 216.209.153.17 16:39, 16 December 2005 (UTC)
Lemons
When a lemon is cut in half you can see that it is actually made up of several smaller sections. For example this lemon is made of nine sections. Is this the same for all normal lemons? Does this relate also to the number of petals the lemon tree's flowers have? - Theshibboleth 02:44, 14 December 2005 (UTC)
- I suspect that, like with oranges, the number of sections can differ be specimen. According to our article: "In botany, a fruit is the ripened ovary--together with seeds--of a flowering plant." The number of petals on the flower appear not be included in the formation of the fruit and are thus unlikely to affect the number of sections in it. - Mgm|(talk) 09:33, 14 December 2005 (UTC)
- The number of petals on most plants is not variable. Flower structures are often used to differentiate between speicies, thus more petals would denote a different species (although this is not always true, otherwise "she loves me/she loves me not" would be rather predictable). If you look around for pictures of orange blossoms [1] you'll note that they all have five petals.
- In fact, [László Mérő] mentions this in his book ""Mindenki másképp egyforma"" (the English translation apparently has the title ""Moral Calculations""). In chapter 11, he states that the ""loves me, loves me not"" game is indeed sort of deterministic for this exact reason (most flowers have flowers have an odd number of petals), but it's not entirely deterministic as often one or more petals have fallen off the flower. – B jonas 19:59, 15 December 2005 (UTC)
- The number of carpels determines the number of sections. The carpel number is not necessarily related to the petal number. David D. (Talk) 17:44, 14 December 2005 (UTC)
- This web site is quite clear. You should find it useful. David D. (Talk) 02:26, 16 December 2005 (UTC)
MAPI Service
Ever since I installed the Norton SystemWorks 2006, Norton Firewall 2006, Norton Antispam 2005, I have been getting the following window every time I turn on my computer.
- Managed MAPI Service Catastrophic Failure
- Unknown error
The only button on the small pop-up window is OK. How do I stop the window from popping up? My operating System is Windows XP Media Center Edition 2005.
--66.81.19.12 03:18, 14 December 2005 (UTC)
- See Symantec's solution for that problem here. -- Daverocks 09:25, 14 December 2005 (UTC)
- Symantec's solution is downloading and installing updates for Norton Antispam 2005, but my update gets aborted whenever I try to get the update -- this only happens for Norton Antispam. I get the following error message.
Windows XP 5.1.2600 Service Pack 2
AntiSpam Feature 2005.1.02
LiveUpdate was not able to complete this update.
Please contact Technical Support and provide all information displayed on this screen. For contact information, go to Help->Technical Support from your Symantec product.
The files below could not be updated by LiveUpdate:
File: C:\PROGRA~1\COMMON~1\SYMANT~1\Options\UIHelper.dl^ 100448 Bytes 9/23/2005 17:38:44 v2006.2.0.153.
- Have you tried uninstalling and reinstalling Norton Antispam? That might solve your problem (you may need to uninstall and reinstall the rest of the suite as well, I don't know how tightly integrated it is). — QuantumEleven | (talk) 08:32, 16 December 2005 (UTC)
Thank you.
Slashdot question
Screenshot linked to save space
What does the text "n more" mean under some of the section links in the slashdot sidebar? --pile0nadestalk | contribs 04:41, 14 December 2005 (UTC)
I believe in Slashdot terms it means there are n more articles in that subject that where not shown on the front page. --Martyman-(talk) 04:42, 14 December 2005 (UTC)
Thanks --pile0nadestalk | contribs 04:51, 14 December 2005 (UTC)
Foot vaccination in India
John a Wikipedia question sent the following question to the Wikimedia Help desk.
"My friend a Lady is an orphan born India 1954. She is vaccinated on the sole of her right foot? is this normal in India?"
If you can help answer the question it would be greatly appreciated. Capitalistroadster 07:15, 14 December 2005 (UTC)
- I'm not an expert in the field of vaccination, but I believe that it's a common way of vaccinating infants (in India as well as the Western world). It may be because the veins in her arm were hard to see (so they used her foot instead), or perhaps, she already had several vaccinations in her arm, so they used her foot to give the arm time to heal. - Mgm|(talk) 09:37, 14 December 2005 (UTC)
- I have never heard of vaccinating on the sole. This of course does not mean it is not "common" in Asia, but I doubt it is "common in the Western world." The most common site in the US in the years it was being done was the upper arm. Smallpox vaccination involved scratching the skin (which is why it left a visible scar), not finding a vein or giving an injection, so the vein explanation or multiple injection explantion is irrelevant. alteripse 18:13, 14 December 2005 (UTC)
- When I said infants I'm referring to kids no older than 1 year. I've heard of such a practice and I'm not claiming it's common practice for anyone over that age. - Mgm|(talk) 20:37, 14 December 2005 (UTC)
- I think everyone has stopped doing smallpox now. Just for my own education, where and when was foot vaccination in infants common? alteripse 21:48, 14 December 2005 (UTC)
- My research adviser from undergrad was vaccinated on the sole of her foot so that the scar wouldn't show if she wore something sleeveless. She was still kind of bitter that her doctor was that sexist; he vaccinated boys on the arm, where it hurts much, much less. I was never quite impolite enough to ask her age directly, but I think this practice has been discontinued, and I know it wasn't widespread; my mom's vaccination scar is on her arm. --Joel 13:30, 21 December 2005 (UTC)
what is the bandwidth required for on-demand computing
what is the bandwidth required for on-demand computing where processer is far away and only input and output devices are here?
- It depends on the application(s) in question. You need enough bandwidth to make the use of a distant (presumably more advanced) processor preferable to a local one. — Lomn | Talk / RfC 14:19, 14 December 2005 (UTC)
Origin of the word Cancer
Where does the word cancer come from? I heard it is originated from hippocrates, who investigated breast cancer and the spiny venes reminded him of a crustacean. But how does that explain the word cancer? Thanks, Meike
- This seems to be about right; according to Paul of Aegina, Hippocrates made the connection because "the veins stretched on all sides as the animal the crab has its feet". According to Webster's Revised Unabridged Dictionary, "It was so called, perhaps, from the great veins which surround it, compared by the ancients to the claws of a crab." The tumor meaning has been attached to cancer for a very long time. [2] ‣ᓛᖁ♀ᑐ 13:39, 14 December 2005 (UTC)
- To answer you question "How does that explain the word cancer" more specifically, the astrological sign "cancer" is represented by the crab. Jasongetsdown 15:51, 14 December 2005 (UTC)
- Never mind astrology. Cancer is the Latin word for crab. --Heron 17:25, 14 December 2005 (UTC)
- In some languages (Danish, Norwegian and 19th century Swedish come to mind as I'm scandinavian) - the name actually is the native name of a similar (but not identical, compare crab) animal, the crayfish. (it's "kræft" in da, "kreft" in nb, "kräfta" in 19th century Swedish but "cancer" in modern Swedish). Unfortunately, I don't know the origins. It might a mistranslation or have its own origin. TERdON 23:57, 14 December 2005 (UTC)
- These are probably all derived from a Germanic root meaning "to claw" which may also have produced crayfish by folk etymology. [3] ‣ᓛᖁ♀ᑐ 00:20, 15 December 2005 (UTC)
Blood types
What is the difference between someone with a positive blood type and a negative, for example A- or A+ thanks,--anon
- See our article on blood type. TenOfAllTrades(talk) 14:52, 14 December 2005 (UTC)
Yeah, it didn't explain it.--anon
- The section Blood type#Rhesus system (CDE) explains the plus-minus. If you're asking what the difference is between people of different blood types -- none, other than their ability to safely donate or receive blood of particular types. --jpgordon∇∆∇∆ 18:02, 14 December 2005 (UTC)
- Plus/minus refers to the presence of the Rh factor. Rh is an antigen which may or may not be on the surface of red blood cells. If you have it then your blood type is (+), if you don't then it is (-). Why we have a gene for this antigen? We do not really know, it may be some evolutionary remnant. Nrets 19:34, 14 December 2005 (UTC)
- FWIW, see Blood type diet. Zoe (216.234.130.130 22:52, 14 December 2005 (UTC))
Lymph nodes
How many lymph nodes does a human have on average?
- Humans have approximately 500-600 lymph nodes. --David Iberri (talk) 15:30, 14 December 2005 (UTC)
- Thanks. Added it to the article. --WS 22:09, 14 December 2005 (UTC)
DBMS
WHAT DOES A DATA BASE MANAGEMENT SYSTEM ALLOW US AS USERS TO DO?
- Nothing. It organises data. But if you add in applications that use the DBMS, then you as end users gain the ability to work with that data. Most business processes these days involve dealing with large amounts of data, from contact lists to human genomes, and the DBMS is charged with storing, organising, and providing efficient access to that data. Does that hope with your homework? Notinasnaid 16:06, 14 December 2005 (UTC)
- It also depends on the system. Many computer infrastructure providers use similar terminology for systems that have extremely different capabilities. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 22:06, 14 December 2005 (UTC)
DB Systems of NASA
The latest issue of e-week has a truely fascinating article on how NASA presents different kinds of data for people to utilize. NASA has defined 12 different domains in which Earth Science Satelites has beneficial applications, organizing that data into different collections optimized to the needs of those applications. I would hope that there are Wiki articles some place on some of these concepts.
- ECHO = Earth Observing System Clearninghouse
- ESDIS = Earth Science Data and Information Service Project
- SOA = Service Oriented Architecture
- UDDI = Universal Description, Descovery, Integration
User:AlMac|(talk) 20:55, 15 December 2005 (UTC)
PC to mobile and mobile to PC
Many services offer free SMS from PC (say messenger) to mobile. Is there mobile to PC service apart from the service which offers users ability to reply to PC-to-mobile messages?
- Yes, my GSM provider offers such a service [4]. All you have to do is send an SMS to a special number, and they'll send an e-mail, so this is available from any old mobile phone. The recipient address, the subject of the message, and its body are all specified in the same message. This, of course, limits you to short e-mails only. It costs the same as a normal SMS I think, but I'm not sure. – B jonas 19:42, 15 December 2005 (UTC)
TV and movies often show people faining when they see something shocking or disturbing. Does this happen in real life? Fainting doesn't say. --Quasipalm 18:45, 14 December 2005 (UTC)
- Yes, one may faint in response to strong emotions or stress. It's called vasovagal syncope. Let me know if you have any questions. — Knowledge Seeker দ 19:31, 14 December 2005 (UTC)
HTML Forms (Wikipedia-related)
The "section edit" form on Wikipedia contains a one-line "subject/headline" field and a multiline text box (see http://en.wikipedia.org/w/index.php?title=Wikipedia:Sandbox&action=edit§ion=new). Currently, if you hit "Enter" in the subject/headline field, most browsers will treat this as a "submit" request, apparently because this is the only one-line field on the form (Bugzilla:4273). Is there any way to change the table markup so that the form will work the same way, but that browsers won't treat Enter as a "submit" request? From what I can tell, the Summary field is an input field, while the text box is a textarea, but I'm not very good with html forms. -- Creidieki 20:08, 14 December 2005 (UTC)
- There's a javascript trick for this. Most browsers seem to treat hitting Enter on a form as a click on the first submit button on that form. Therefore inserting a transparent 1×1 pixel image button at the top of the form and giving it an onclick handler that returns false will prevent hitting Enter from submitting the form. It's a crude hack, I know, but it seems pretty reliable in practice. —Ilmari Karonen (talk) 22:05, 14 December 2005 (UTC)
help me please (urgent)
I must be knowing any effect or dangers that would be coming if someone (not being me!) were to be ingesting 5 heroin filled game rabbits. please be helping. Should I be going to the hospitle after doing that? This is urgent!
- 5 heroin filled game rabbits? What the heck is a heroin filled game rabbit?--Aolanonawanabe 21:50, 14 December 2005 (UTC)
- I still want to know what a heroin filled game rabit is--Aolanaonwaswronglyaccused 03:37, 17 December 2005 (UTC)
- Yes, probably. Heroin overdose can be extremely dangerous. ‣ᓛᖁ♀ᑐ 21:45, 14 December 2005 (UTC)
- Are we to assume the rabbits have been cooked? And did the rabbits ingest the heroine or were they injected with it? If injection, before or after their death?
- my suggestion is
- immediately without delay to get the victim to a hospital to have their stomache pumped out.
- be prepared to give a statement to the police in which the cross examination may last XXX hours.
AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 22:09, 14 December 2005 (UTC)
- Why would you need to be able to give a statement to the police? Wouldn't the doctors reporting that be a violation of medical privacy? -- Creidieki 04:21, 16 December 2005 (UTC)
Depending on nation state etc. there are often laws requiring medical personnel to inform the police when a person's medical condition implies that some reportable crime may have occurred, such as
- gunshot
- illegal drugs consumed
- rape
- child abuse
User:AlMac|(talk) 17:43, 16 December 2005 (UTC)
- Interesting stuff about medical privacy. Heroin filled game rabbits are still kind of confusing me however.
- Apart from the obvious oddities already mentioned - ingesting five rabbits? Were they baby rabbits? DirkvdM 10:29, 17 December 2005 (UTC)
Execute order 66?
As you all know in th uber popular movie return of the sith, they made a clon army that without knowing about it, was programmed to assasinate the good guys in the movie, even though they were trained from birth to be clones? But could or how would this wor in real life? Could it have been done and we might not ven know about it? until late? opinions? science? facts?- anon
- Current state of art ... the clone arrives as a fetus, with normal speed development same as an ordinary child.
- Boys from Brazil is doable with current technology.
- Jurassic Park not yet.
- There was another thread somewhere now in the archives, about risks of science, when commercial interests are more interested in short term profits than safety.
- Mad Cow disease is man made accident, that originated with Mad Sheep Scrapie got passed to cattle, then thanks to careless experiments with Deer, it is now in the wild, at least in North America, with most wild animals susceptible, because the food chain that eats the Deer, also gets this. Pigs and other livestock also got it. So this is not because of evil intent, but short cuts thanks to greed.
AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 22:13, 14 December 2005 (UTC)
- The clone troopers in Revenge of the Sith weren't actually genetically programmed to execute Order 66, they were trained to obey the orders of the Supreme Chancellor above all others. --Canley 23:20, 14 December 2005 (UTC)
Toe Jam?
What is Toe Jam and how is it formed?
Toe Jam is a sweet preserve made from toes. First, debone the toes, removing the nails if necessary. Next, chop the toes into small cubes about 5mm x 5mm x 5mm. Put in large pan. Add equal weight of sugar, and enough water to fully dissolve the sugar. Boil until thick. Alternately, a toe jam is when you jam your toe against a wall, thus compressing the bones. --YixilTesiphon Say helloBe shallow 22:53, 14 December 2005 (UTC)
- According to wiktionary:toe jam, it is "the accumulated matter in between the digits of the foot." Like navel lint (I can't believe that's an article), it's mainly composed of stray clothing fibers and dead skin cells. —Charles P. (Mirv) 23:00, 14 December 2005 (UTC)
html/java
Well, i am doing a website and i want to create a login/sign up but i don't know how to do that. Can you help me? -Mumai
- If all you want is to make some part of your website accessible with a password, you have to configure the webserver so. Read the Apache manual for example: [5], although I guess there may be more comprehensive descriptions too. -- (sorry, it seems I forgot to sign this) B jonas 19:25, 15 December 2005 (UTC)
- There are host sites you can buy into, that come almost default that way, such as Weblogger.
- Setup the site as restricted, then there is a place you go to define new users and invite them to join, or send them password (like in e-mail which is not exactly secure).
- This kind of system is for people who want to be able to use the power of the Internet, without having to learn the programming that is needed to make things work.
December 15
Hydroelectricity Power
Where geographically is hydroelectricity used?
- You might want to read Hydroelectricity. -- Rick Block (talk) 01:05, 15 December 2005 (UTC)
Nature peer review
How much can be extrapolated from the results of Nature's review of Encyclopedia Britannica and Wikipedia? How should the margin of error for the average number of mistakes per article be calculated? ‣ᓛᖁ♀ᑐ 01:21, 15 December 2005 (UTC)
- They don't mention the depth of coverage for each article so its hard to extrapolate. I assume they picked articles that were similar. If so, looking through that list of errors compared to Britannica, i'd say that wikipedia is in very good shape. David D. (Talk) 01:26, 15 December 2005 (UTC)
- Unfortunately the standard deviation for the number of mistakes per article is slightly higher for Wikipedia (3.47) than for Britannica (2.43), suggesting our quality may be more variable. ‣ᓛᖁ♀ᑐ 03:04, 15 December 2005 (UTC)
- Well no surprise there. Some of the wikipedia science articles are terrible. But they are all a work in progress and will improve eventually. David D. (Talk) 04:12, 15 December 2005 (UTC)
Is there currently a drive or WikiProject to improve the quality of the articles in question, or for that matter, does anyone maintain a list of WP articles mentioned in the media as needing improvement? I would imagine a list of those articles would be good to have, as experts will be attracted to them, and they're also likely vandalism targets, so they should be watched and improved. This is just a suggestion, but if it doesn't exist I'd like to start something like that.
Did I deviate too far from science to be on the reference desk? I hope not. --ParkerHiggins 03:35, 15 December 2005 (UTC)
- maybe Wikipedia:External peer review would be helpful? Broken S 03:38, 15 December 2005 (UTC)
- I made a little list that at least temporarily is here, but the improvement drive is really at Wikipedia:External peer review. The task is complicated by the fact that Nature did not specify the errors of fact, omission, or misstatement.- Nunh-huh 03:40, 15 December 2005 (UTC)
- A number of people posted on the village pump that they got responses back from nature saying they are working on publishing the list of errors on their blog, so stay tuned. - Taxman Talk 21:40, 16 December 2005 (UTC)
- Nature has a blog? Do you have a link? David D. (Talk) 21:45, 16 December 2005 (UTC)
- Yes, amazingly enough they do. Here's the link to the issue at hand. You may also be interested in the coverage at Wikipedia:External peer review. - Taxman Talk 17:59, 19 December 2005 (UTC)
- Why didn't the Nature reviewers correct the errors they found, when they found them??? MPF 23:44, 19 December 2005 (UTC)
- Yes, amazingly enough they do. Here's the link to the issue at hand. You may also be interested in the coverage at Wikipedia:External peer review. - Taxman Talk 17:59, 19 December 2005 (UTC)
- Nature has a blog? Do you have a link? David D. (Talk) 21:45, 16 December 2005 (UTC)
- A number of people posted on the village pump that they got responses back from nature saying they are working on publishing the list of errors on their blog, so stay tuned. - Taxman Talk 21:40, 16 December 2005 (UTC)
- This is exactly what i was looking for. Thanks a bunch, guys. --ParkerHiggins 03:46, 15 December 2005 (UTC)
- Alternatively, at least one of the science WikiProjects is looking closely at the results, and trying to make sure that we do better next time! Physchim62 (talk) 18:00, 15 December 2005 (UTC)
How long can the human body go without sleep?
Just wondering--Aolanonawanabe 03:48, 15 December 2005 (UTC)
- sleep deprivation gives an answer. - Nunh-huh 03:50, 15 December 2005 (UTC)
- Ah thanks, I knew finals were torture, never knew it was that literal (: --Aolanaonwaswronglyaccused 03:36, 17 December 2005 (UTC)
proper sound loudness unit for humans
The decibel is a commonly used unit of sound loudness. However, according to the article, a decibel is a dimensionless unit. There are several variations on the decibel listed in the article, but I'm unable to figure out which one is correct. Which decibel variant is the correct one to use when talking about the subjective loudness of a sound to humans? Or is merely decibel sufficient? --Cybercobra 04:20, 15 December 2005 (UTC)
- A bel is just a factor of 10. A decibel is one tenth of that, so it's a factor of 101/10. The actual unit for measuring sound intensity is the watt per square meter, but it's much more commonly stated as a number of decibels in relation to 10−12 W/m2. For example, 30 dB is 1000 times that intensity, so 10−9 W/m2.
- However, sound intensity is not the same as subjective loudness. No matter how loud a sound is at 50 kHz, you won't be able to hear it (but your dog might). Apparently the unit for subjective loudness is the phon. —Keenan Pepper 05:49, 15 December 2005 (UTC)
- Thanks. I've improved the Category Human-based units of measure accordingly. --Cybercobra 03:08, 16 December 2005 (UTC)
- You're correct about a decibel being dimensionless, so it really just describes ratios. When used in the audio world, it's often used with a specific reference. While people may say "that sound was 85 decibels", they really mean something that should be written as something like 85 dB(SPL), which compares it to a reference level of 20 micropascals. Decibels have many other standard references, such as dBm, dBv, etc... kmccoy (talk) 00:50, 22 December 2005 (UTC)
- Thanks. I've improved the Category Human-based units of measure accordingly. --Cybercobra 03:08, 16 December 2005 (UTC)
Acetabulum - are unit and body part related?
Is the unit Acetabulum related to the same-named part of the human body (e.g. does the unit = the volume of bodypart)? Or is it merely coincidence? --Cybercobra 04:25, 15 December 2005 (UTC)
- They both take their name from the Roman "vinegar cup". They are related by appearance (at least in an anatomist's imagination) rather than by volume. - Nunh-huh 04:55, 15 December 2005 (UTC)
- Duely noted, Category Human-based units of measure improved accordingly.--Cybercobra 03:10, 16 December 2005 (UTC)
Capacity of Twisted pair & a Coaxial Cable ?
- .How much data can be transferred at a same time in a "Twisted Pair" & a "Coaxial cable"?
- .What is the total capacity those cable?
- (User:AlMac|(talk) edited to make it look nicer)
Part of the answer to the question is related to the structure of the data, and packing. Data is being transmitted at the speed of light along the cable, right? It is going two ways at the same time. There are multiple parallel data, like in a TV signal, there is both audio and video, in parallel with each other.
Advantage of one over another is resistance to interference with the primary signals. User:AlMac|(talk) 21:08, 15 December 2005 (UTC)
Assuming you mean in terms of computer networking cable, thinwire (co-ax ethernet) tops out at 10 MiB per second, and twisted pair goes up to (at Cat 6) 1GiB per second - assuming you have the correct hardware on both ends. Ethernet has more information. I'll note that, in principle, there isn't really a difference between the maximum data throughput of the two cable types, but as twisted pair was a much nicer topology, noone bothered designing and standardising aything faster through co-ax. Syntax 02:39, 20 December 2005 (UTC)
MS Word
My computer froze, I had to shut down, and when I opened MS Word a chunk text in a .doc file was replaced by rectangles ( )! What should I do? Neutralitytalk 04:47, 15 December 2005 (UTC)
- See if you can open the recovery file. (Search Word's help to find out where it is, it's different for different setups and platforms). - Nunh-huh 04:52, 15 December 2005 (UTC)
- I hope you haven't closed Word yet - doesn't it delete all the recovered documents from the previous session upon exit? It should also offer you the choice of the file as last saved by you (which I would imagine is good), and the automatically saved versions... Enochlau 05:14, 15 December 2005 (UTC)
- Darn. I did. However, I managed to recover most of the file anyway but have to rewrite a paragraph. --Neutralitytalk 05:39, 15 December 2005 (UTC)
- I hope you haven't closed Word yet - doesn't it delete all the recovered documents from the previous session upon exit? It should also offer you the choice of the file as last saved by you (which I would imagine is good), and the automatically saved versions... Enochlau 05:14, 15 December 2005 (UTC)
Universe
With the galaxy, sun and earth all moving, is it possible to stay still in one spot in space?
- It depends how many variables you use to define "one spot", if you mean X,Y, and Z coordinates are all kept constant, than sure it's possible-ish, but since the expansion of the universe is modeled in 4D, I'd say that last axis might complicate matters--Aolanonawanabe 16:28, 18 December 2005 (UTC)
- You can stay still with respect to any chosen Frame of reference. Whether there's an absolutely neutral frame of reference is perhaps another question. -- Rick Block (talk) 05:10, 15 December 2005 (UTC)
- By the principle of relativity, you cannot "stand still" in one place. Not moving and moving with a constant velocity look and feel exactly the same. As Michelson and Morley demonstrated with their experiment, there is no absolute frame of reference by which we can measure whether we are "moving" or "staying still" in space. Enochlau 05:12, 15 December 2005 (UTC)
- Determining your position requires a reference point, such as you to the Earth, or the Earth to Sun, or the Sun to the Milky Way. So how are you to determine your position in space? You to the Cosmic Microwave Background? - Cobra Ky
(talk, contribs) 05:16, 15 December 2005 (UTC)
- This is a tricky question, and depends on what you mean by "stay still" and "in one spot". Until the acceptance of the heliocentric model, most people would have replied "yes" without second thought (Earth doesn't move, therefore if you stand still, you aren't moving). With the adoption of heliocentricism, the notion of an "absolute center" shifted to the Sun, with various explanations for the motion experienced by everything else (including epicycles). Now special relativity is popular, in which there is neither an absolute center nor an absolute zero speed — but there is a relative zero speed, which is the speed of the observer. So by relativity, you can consider yourself to stay still in the exact ___location where you are, which of course is practically meaningless. ‣ᓛᖁ♀ᑐ 05:20, 15 December 2005 (UTC)
- Actually, Eienstein's theory of relativity does not state that everything is relative to everything else, just to certain constants, so yes, it is possible. Max 216.209.153.15 14:09, 15 December 2005 (UTC)
FM radio
How can i make a radio with household parts, and parts from Old radios, cell phone, and mini tv's?
- Building a "crystal set" is suprisingly easy. All you need is a coil of wire, a diode (that's what the crystal was for; now diodes are really tiny and cheap), some earphones, and a capacitor that you can change to tune it to different stations. A crystal set is cool because it doesn't need any power other than the radio waves (but therefore there's no way to turn up the volume). You can probably figure out how to build one just from the Wikipedia article.
- Of course, that's only for AM radio. Building an FM radio is a lot harder. A quick Google search turned up this: [6]. —Keenan Pepper 07:00, 15 December 2005 (UTC)
- Actually, I just read that it is possible to tune in to an FM station with an AM receiver such as a crystal set. It depends on the circuit having a very high Q factor, and of course the quality won't be that great. It works best if you tune to one side of the FM band rather than the center. See [7] —Keenan Pepper 07:18, 15 December 2005 (UTC)
computer simulated machine
hello
i have heard about in servicing field one machine used for daignosing the fault that is csm or computer simulated machine.
let me know the details
Solar Radiation
Sun had been radiating enormous amounts of energy since its formation. has it been loosing its mass accordingly?. If so ; Can it be quantified?. What are the effects on planetary orbits , if any?
If not , why so? sombansil
- Yes, it has been 'losing' mass (to be correct, converting mass to energy through nuclear fusion). Yes, this mass loss can be calculated, since we know how much energy is produced by a hydrogen-helium fusion reaction, and how much mass is converted to energy during this reaction. Taking an estimate of the total energy output of the sun over its history, we can estimate how much mass it has 'lost'. However, compared to the total mass of the sun (1.9891 x 1030 kg) the mass decrease is virtually negligible, and certainly not enough to have a visible effect on planetary orbits.
- Addendum: it also loses mass through solar wind. From that article:
- Approximately 1×109 kg/s of material is lost by the Sun as ejected solar wind, about one-fifth that lost due to fusion, which is equivalent to about 4.5 Tg (4.5×109 kg) of mass converted to energy every second.
- — QuantumEleven | (talk) 10:09, 15 December 2005 (UTC)
- Just a quick reminder to do your own homework. "If not, why?" is usually a dead give away that you're doing someone's homework. To the poster, instead of asking a homework question verbatim, just point out where you're having difficulty. --Quasipalm 18:22, 15 December 2005 (UTC)
Installing SATA and ATA drives together
Is it possible to mix (install together) SATA and PATA hard drives in a single system? If so, how should I do it? Is it a good idea? Thanks in advance. 61.94.149.177 10:28, 15 December 2005 (UTC)
- I've got such a setup and it works. The very fact that there are motherboards with both SATA and PATA connectors should be a sufficient indicator that it should work. Since SATA is fairly new there may be some problems with that, but I don't see how the combination could cause any problems. If I'm not mistaken, the access of the drives is the same, irrespective of whether it's a SATA, PATA or SCSI, because the translating is done on the drive/interface itself. (Not sure if I put this right.) DirkvdM 11:57, 15 December 2005 (UTC)
- All mobos I've seen that use SATA also have some standard ATA connectors so that you can plug in CD-Rom drives, etc. (AFAIK almost all SATA devices are hard disks). You should be able to add standard ATA HDs to those connectors without any problems. --Bob Mellish 16:57, 15 December 2005 (UTC)
Water airplane crashes
Have there been any crashes of commercial airliners into bodies of water (lakes, oceans...) where (some) people on board have actually survived? I know that there are quite a few land crashes with few or no casualties, but I can't think of any water landings where not everyone was killed... — QuantumEleven | (talk) 12:44, 15 December 2005 (UTC)
- Thanks! That's a pretty exhaustive list, but sadly confirms my suspicions that very few large jet aircraft have survived a water landing... — QuantumEleven | (talk) 14:55, 15 December 2005 (UTC)
- After checking out that list, it doesn't seem to me to be that dismal of a figure. Many low-passenger-count flights had 100% survivor rates, and many large-passenger-count flights had minimal fatality rates. I guess it's all about perspective, though.
Dental x-ray
- This question no verb. —Keenan Pepper 16:40, 15 December 2005 (UTC)
What is histrionic personality disorder?
You do realize this is an encyclopedia, with over 800,000 articles covering a broad range of topics? I suggest you look it up. -- Rick Block (talk) 16:51, 15 December 2005 (UTC)
clean or unclean?
Try clean and/or unclean. Thryduulf 14:35, 15 December 2005 (UTC)
Crushed stone
If you take one cubic metre of stones and crush them in a crusher to produce finer aggregates, what will the volume of resulting aggregates
a)>1 cubic metre b)=1 cubic metre c)<1 cubic metre
Thank You
Depends on the size and shape of the original stones, I'd say. For example, if you start with a single cubical stone with one meter edges, the answer would probably be a. If, on the other hand, you start with spherical stones 50 cm across, packed into the same one meter cube (8 will fit exactly), the answer is almost certainly c. And of course, if you only measure the actual volume taken by the stones, not counting the spaces between them, then the answer is always b by definition. --Ilmari Karonen (talk) 14:21, 15 December 2005 (UTC)
- The answer is (c), your homework is to explain why. Physchim62 (talk) 18:04, 15 December 2005 (UTC)
- I'd support (c) too, but I'm not sure. If I'd want to know this, I'd take a vesel with a scale on its side, put some breakfast cereals in it, write up the volume from the scale, crush the cerial to very small bits (this is the difficult part), and see if the result will fill the vessel to a higher or lower level. Of course, stone could behave differently. – B jonas 19:11, 15 December 2005 (UTC)
- I would have gone for c) too, but notice that Ilmari has already refuted that. Very clever! (Though the last bit is a bit corny). But I'm sure one could generalise this in a formula. Actually, I believe there is a form of geometry that deals with just this sort of thing, but I can't think of the name. Topology doesn't seem to be it. DirkvdM 08:04, 16 December 2005 (UTC)
- In fact if you consider the stones to be close-packed spheres at all stages of crushing, the answer is (b), the stones occupy just over 74% of the volume regardless of radius. See also Kepler conjecture. Physchim62 (talk) 10:22, 16 December 2005 (UTC)
- ...except that this holds only if they are all the same size (the packing generally gets denser if there are stones of various sizes), and ignores possible extra gaps at the edges of the container (which will on average be roughly proportional in volume to the radius of the smallest stones). Not to mention the fact that real stones are rarely spherical, especially not after crushing. And then there's the fact that randomly packed granular materials may not even have a constant volume — they may settle (or expand) when shaken. —Ilmari Karonen (talk) 21:38, 16 December 2005 (UTC)
just a question
I was talking with a teacher and we came across the fact that a green bean could be a vegetable or a fruit and we were wondering which one it is. It is not a root or a leaf however it has beans and that means that they can reproduce and regrow. Therefore i just need to know whether beans are a fruit or a vegetable. Thank You, Melinda
- A fruit is a scientific definition, while a vegetable is a conventional one. Consequently, the two are not mutually exclusive and a given object (say, a tomato) can be both. A green bean certainly meets the conventional definition of a vegetable, and beans have been legally labeled such, but as a legume, it also meets the definition of a fruit. — Lomn | Talk / RfC 18:47, 15 December 2005 (UTC)
- So alfalfa is also a fruit? So what is the classification of non-legumes like celery?
- No he is refering to the beans themselves being fruit. Alfalfa is eaten as the shoots of the plant not the fruiting body so it is a vegetable, not a fruit. If you read Fruit, it explains a fruit is essentially the part of the plant that grows from a fertilised flower and contains the seeds of the plant. If a vegetable is a pert of a plant that does not contain seeds then it is not a fruit. --Martyman-(talk) 22:43, 15 December 2005 (UTC)
Spandex
Does spandex, lycra, or nylon, contain latex?
- This is an encyclopedia. Have you tried looking these things up? -- Rick Block (talk) 20:00, 15 December 2005 (UTC)
- I think spandex, lycra, and nylon are all synthetic polymers, whereas latex comes from a plant. —Keenan Pepper 20:38, 15 December 2005 (UTC)
- If you use the technical definition of "latex", it's quite possible to make a latex of nylon, by producing very fine particles of it, suspended in water.--Joel 13:49, 21 December 2005 (UTC)
technology developed originally for the military but now used in our homes
Hi everybody !
I´m a Brazilian journalist, working for a Science and History monthly magazine.
Right now, I´m doing research to write an article to answer the question "Which products originally invented for the military are now used in our homes ?" (For instance: canned food, the internet, etc.)
I would be most grateful if you could send your answers to this question. I also would be grateful if you could provide names and e-mails of specialists (historians, researchers, sociologists, political scientists, etc) who could be interviewed by e-mail about this subject.
Thank you very much.
Roberto
- You're not, by any chance, writing for Superinteressante, are you? ☢ Ҡieff⌇↯ 04:57, 16 December 2005 (UTC)
You might also find useful info in the History of Space Exploration. Many products and services originally developed for astronauts, such as powdered orange juice, powdered milk, microwaveable instant meals, subsequently found their way into every home. Related to that, look at what has happened with Spy Satelites. Today there are several commercially available views of planet earth connected through the Internet, where anyone can see detail that a few years ago was only available to the military.
Some products and services were invented jointly for the military and for a nation as a whole.
- The Internet was created by the military but it was not soley for the military, it was to provide communications with all sectors of government, business, academia, society, and be reistant to disruption in a disaster. We saw this concept fail in the Hurricane Katrina disaster, at least for the people on the ground there.
- The US Interstate System had a similar joint purpose. At the time of WW II, many of the roads across the USA were not strong enough for the military to get from one side of nation to the other in a crisis, heavy equipment had to go by Railroad. But with the Interstate System, the National Guard and Reserve could be decentralized in many communities, and rapidly get to where they needed. But the financial success of the system needed it to be used by the mass public. It was not just for the military.
- A lot of research into products and services for the military, can be made less expensive per unit person, if the beneficiaries of the work can be extended to the larger population. We see this in protection against various medical risks. The troops need to be vaccinated against a spectrum of diseases and biowarfare risks, then if the threat materializes, populations of whole nations also need protection.
- It has been a while since I saw what progress was being made on cloning limbs to repair self. It may be that US politics has shut this down. The theory was that before going into harms way, troops blood samples would be stored some place, then after they exposed to radiation damage, or lose an arm or a leg, the blood samples be used to grow replacement parts for the injured soldiers sailors airmen, and because it was from their blood, their body would not reject the replacement organ.
User:AlMac|(talk) 21:17, 15 December 2005 (UTC)
- Have a look at the history of computing: one of the first embedded computers was the guidance computer for the Minuteman missile: later versions, along with the Apollo program, pioneered the use of the integrated circuit. SAGE was one of the first real-time computer applications ever built, and pushed the industry along enormously. Heck, Colossus and ENIAC were both used for military purposes. Another classic example of WWII technology applied to home use is the microwave oven, the core of which was the cavity magnetron used in radar.
- GPS, for a loose definition of "used in the home". --Bob Mellish 21:57, 15 December 2005 (UTC)
- Swords to ploughshares is the term you are looking for, though it's currently fairly sparse. Anyone wanna help with that--Fangz 22:33, 15 December 2005 (UTC)
- Aerosol_cans - wikipedia says it was invented not during wartime, but it's first application was during WWII. --24.31.29.171 04:58, 16 December 2005 (UTC)
- Microwave ovens, non-stick pans, smoke detectors, canned food (during the Napoleonic wars... Physchim62 (talk) 10:28, 16 December 2005 (UTC)
- Rapid-fire assault rifles (if your home is in the US). Also, assuming a somewhat loose definition of 'in the home', RADAR. DJ Clayworth 19:14, 16 December 2005 (UTC)
- CDMA, some forms of wireless communications. --129.97.58.55 19:15, 16 December 2005 (UTC)
Many millioms of people died in WWI and WWII and I would not try and justfie the loss of life but think where we would be now had it not been for their sacrifice. Next time you jet off for a week end holiday just remember it is only just over 100 years ago since the first powered flight. Without those wars it is unlikly that aircraft would have developed passed the wood and string stage at this present time. I would hate to try and work out the percentage of tecnological advances we enjoy today that wern't attributable to our need to kill ourselves or to protect ourselves from being killed by our fellow man. With great regret I say long live testosterone.--Eye 16:01, 18 December 2005 (UTC)
- Not exactly used in the home yet, but used all over the place in civilian life, is Radar. Sewe if you can find the book "The Invention that changed the World" about how RADAR was invented, There's fascinating stories in there about how Axis and Allies used different wave lengths, and how they figured that out so they could do jamming. Anyhow, after WW II, RADAR made the Airline industry as we know it today, and great advances in Astronomy, and safer highways. User:AlMac|(talk) 07:45, 20 December 2005 (UTC)
- Check out literature on the History of science. I saw on a recent Science TV channel how Leonardo da Vinci was employed in the development of Mathematics to figure out how to get medieval weapons of warfare to send forerunners of artillery shells to the precisely correct targeting. While that math has advanced to more superior weapons, it has also become available to civilians for other purposes. Most all math today came about thanks to either warfare or early business book keeping. User:AlMac|(talk) 07:51, 20 December 2005 (UTC)
- One of the first documents published by Galileo was a manual for how to operate what he called a "Military Compass" which was something he made in his workshop that was similar to a calculating instrument called a slide rule, something very popular with engineers prior to major development of personal computing. User:AlMac|(talk) 07:55, 20 December 2005 (UTC)
Herb Robert Information
I am doing a science project on The Effects of Herb Robert on Acne Bacteria. i need more information on Herb Robert. The pigments in the leaf that makes it what it is. i am trying to find out what elements make up Herb Robert.
- The wonderful thing about Wikipedia is that you can type in whatever you need information about in the little search box on the left of your screen and hit "go." For example, try typing "Herb Robert." It will take you here. Especially check out this link. I myself know nothing about botany, so that's all I can do. Now to slink back to the Humanities desk... --zenohockey 02:18, 16 December 2005 (UTC)
How do people send me email from fake addresses?
- If you've read E-mail, the basic technique is to write a mail user agent that supplies a forged "from:" header. SMTP is a text-based protocol, and it is quite easy to manually type an entire email message (including whatever "from:" header you'd like) using a raw SMTP connection. The basic insight is that the address information used for the delivery of the message is separate and distinct from any header content you typically see in your mail client. -- Rick Block (talk) 22:57, 15 December 2005 (UTC)
- You should read the RFC about the SMTP protocol there are even some examples in it. The destination mail server can be found if one does a nslookup with type=mx on the destination ___domain. helohe (talk) 09:49, 16 December 2005 (UTC)
December 16
tummy tuck and headaches
I am curious if anyone has linked having abdominal surgery, specifically tummy tuck with causing headaches. Once the tummy has been cut and sewn tight to reduce the area of tissue the torso is then pulled forward into a forward flexive state. Pulling the torso/thoracic into flexion will pull the head into flexion which then puts so much more pressure on the "righting reflex" which causes the cervical musculature to go into hyperextension, thus creating major tension headaches. I have been experiencing this since July, 2005. I would love to speak with anyone on this subject. www.giese@pbcc.edu
Weather
Is there a website besides Weather Underground, that has historical weather information on a daily bases?
- How far back and for which country? --Canley 04:06, 16 December 2005 (UTC)
I was thinking maybe 10-15 years and in the U.S.
- The Old Farmers' Almanac site has a place where you can look up the information. Do you need it in some sort of specific format? --AySz88^-^ 05:23, 17 December 2005 (UTC)
wet wing design
what is the meaning of wet wing design in aviation? what r its advantages?
- Ok, basically there's two main ways that airplanes store fuel: in tanks or in "wet wings". Most aircraft store fuel in the wings, some simply have tanks in the wings like the gas tank in your car. Other, so-called "wet wing" aircraft, seal the entire wing and use that as a tank. Thus the metal on the outside of the wing that defines the wing is the same metal thats holding the fuel. This is advantageos because it means that you don't have to carry extra metal for a separate tank inside the wing, and you can put fuel into every nook and cranny of the wing which means you can store more. However, wet wings are much more prone to leaking and getting them manufactured right can be really tricky. Thus, they're mostly found on larger commercial aircraft, not general aviation aircraft. -User:Lommer | talk 07:50, 16 December 2005 (UTC)
- Should we have an article on this? —Keenan Pepper 20:45, 16 December 2005 (UTC)
- Yes. I'm not entirely sure where to put it though (i.e. what to call the article). I've written most of Aviation fuel, and it would be closely connected with that. Perhaps I'll write an article on aviation fuel systems? Might be a bit hard to find but with appropriate redirects it could work. -User:Lommer | talk 22:48, 16 December 2005 (UTC)
Bird that starts with letter X
What is the name of a bird that begins with the letter X? Thanks for any help. I'm stuck.
- Nullaby (which I think is made up, but I'm not sure) mentions the Chinese Xu Bird (which I think is also made up, but I'm not sure). Jasongetsdown 03:47, 16 December 2005 (UTC)
- According to the OED there is a bird called a xeme, "a bird of the genus Xema; a fork-tailed gull". --Shantavira 11:42, 16 December 2005 (UTC)
- You might have more luck if you moved the question to the Language reference desk. JackofOz 22:58, 16 December 2005 (UTC)
Annoying spyware
Something annoying starting to occur on my PC. On my Internet browser, when I click Google search results, the page goes to MorwillSearch.com. This doesn't happen with other links. I go up to the URL, press enter, and can access the page I intended, but this is frustrating. I've run AdAware and Spybot, but to not avail. Advice? Neutralitytalk 04:35, 16 December 2005 (UTC)
- You might try HijackThis. -- Rick Block (talk) 05:11, 16 December 2005 (UTC)
- Yes. Hijack This will solve this problem. But be careful which lines you delete when you run it, and make sure you save a backup. Usually it's pretty easy to see which lines should be excised. (any containing Morwillsearch.com, for a start) Proto t c 10:43, 16 December 2005 (UTC)
- Most likely this is a browser helper object (BHO) if you are using Internet Explorer which detects certain URLs and words to redirect you to sponsored links. If any strange toolbars have appeared recently, see if you can uninstall it. Otherwise, take the advice of the others and use HijackThis and delete the appropriate line. This will be labelled 'BHO', but remember Proto's advice! Archer7 17:52, 18 December 2005 (UTC)
- Yes. Hijack This will solve this problem. But be careful which lines you delete when you run it, and make sure you save a backup. Usually it's pretty easy to see which lines should be excised. (any containing Morwillsearch.com, for a start) Proto t c 10:43, 16 December 2005 (UTC)
Heating car in winter
Does it burn extra gas to heat a car? If I leave the heater off, will I get better milage? --24.31.29.171 04:53, 16 December 2005 (UTC)
- No, because the engine produces so much waste heat anyway. Usually the radiator pumps the extra heat to the outside of the car; when you turn the heater on some of it is directed inside instead. —Keenan Pepper 05:05, 16 December 2005 (UTC)
- Considering how hot it gets in a car when you turn the heating up all the way, I wonder how much energy is lost. The efficiency of getting the heat into the car is probably very low and a car is badly isolated and moving fast, which causes a lot of heat loss. If, despite this, you can still get the interior of a car so hot (with just waste energy!), then the energy consumption of a car is probably way higher than the heating of an average house. Then again, one doesn't drive a car constantly (usually about one hour per day). So I wonder what consumes more energy, driving a car for one hour or heating a house for, say, the equivalent of 8 hours in a temperate climate (no heating in summer and low at night). Is there a good site for energy footprint of not just cars and house heating but also household appliances and such? I can't find one, most things I find are cute little quizzes and no simple info. How hard can this be?
- However, my search did teach me this little tidbit: "If everyone in the United States made sure their car tires were adequately inflated (through weekly checks), gasoline use nationwide would come down by 2 percent." And keeping the car tuned in other ways can add another 10% efficiency (for the car that is). Of course, having a car that has an engine that's just big enough for what you need will make the biggest difference - in most cases (especially in the US where huge cars are popular) I assume less than half the 'horsepower' would be sufficient.
- One of the best lists I've found so far is this one: [8], although, ironically, it doesn't include the car. Somewhere else I read that a typical electric car uses about 20kWh of energy to drive 100km. Suppose a commuter drives 50 km per day, 20 days per month. That would mean 200kWh per month. The table gives about 1000 kWh per month, which is 5 times as much. But one doesn't normally have all those things and a comparison with an electric car isn't entrirely fair (also because they're usually lighter than 'normal' cars). And I haven't included shopping (the frequent stops in city traffic consume loads of energy), so I suppose that for an average household the car consumes about 1/3 of the energy. No wonder a minor thing like keeping the tires appropriately inflated can make such a big difference. DirkvdM 10:10, 16 December 2005 (UTC)
- Me again. Found this (from [9]: In the US, cars and light trucks account for 40 percent of the nation’s oil use.
- It depends. In most cars, no. In some (a very small few), yes. In most cars the heat surplus is big enough, but there are some efficient cars where it isn't enough (low-power highefficiency diesels, hybrids etc come to mind) where the heat output, at least in cold conditions, just isn't enough (at least to heat the car rapidly - even though the heat output is sufficiently big to maintain the temperature, it might not be enough to heat the car in less than 100 km...), and an extra, electric, heater also is installed. Using this would of course mean raised fuel usage. TERdON 00:20, 19 December 2005 (UTC)
- The other exception is the early Volkswagen Beetle, which has a rear-mounted, air-cooled engine, which made the prospect of piping hot water from it a little too difficult during the first few models. These had a gasoline-powered furnace in the cabin, which (according to some old folks I talked to years ago) ran the risk of explosion if it was turned on without ignition. --Joel 14:01, 21 December 2005 (UTC)
meaning of cephalopodes
You'll be wanting our article on cephalopods. Physchim62 (talk) 10:31, 16 December 2005 (UTC)
Light
How is diffraction different from refraction?
- They differ in several ways; but they're similar in that they can both be easily looked up in Wikipedia. See Diffraction and Refraction. --David Iberri (talk) 12:19, 16 December 2005 (UTC)
- The colors of light reflected from the bottom of a CD are the result of refraction from the closely spaced grooves. The colors of light spanning the sky in a rainbow are the result of diffraction through myriad tiny raindrops. In the first case we see color because different wavelengths are selected by the groove spacing; in the second, because different wavelengths are dispersed to different positions in passing through the water droplets. Both depend on wave mechanics. --KSmrqT 12:53, 16 December 2005 (UTC)
- Other way around - diffraction from a CD, refraction+dispersion for raindrops in rainbows and prisms. --Bob Mellish 14:19, 16 December 2005 (UTC)
microbiology
... which, believe it or not, we have an article on! — QuantumEleven | (talk) 13:13, 16 December 2005 (UTC)
wat kind of question is that ???
- Not a question. Merely a word. Halcatalyst 05:38, 19 December 2005 (UTC)
SAS date reference
Why does SAS (developed by Jim Goldsmith some thirty years ago and now used practically everywhere) use Midnight on the 1st of January 1960 as their date reference point?
ie that date is defined as zero, dates before are negative (31st december 1959 is -1) and dates after are positive (2nd jan 1960 is 2). it also counts hours and minutes and seconds from midnight on that date. So it must be significant in some way. Any ideas anyone? Cheers. James. --62.49.11.11 15:35, 16 December 2005 (UTC)
- You seem to have made a mistake. If 1960-01-01 is day 0, then 1960-01-02 would be day 1 (assuming days are numbered serially). --Juuitchan
SAS Reference date (correction)
sorry it was James Goodnight. Apologies. james (again)--62.49.11.11 15:50, 16 December 2005 (UTC)
- Well I'm not sure what SAS is (is that the same as SAS System?) but 1st Jan 1960 was probably an epoch date on the first system it was implimented on (or if not, was chosen as an epoch date by the programmers), in the same way that 1st Jan 1970 is the Unix epoch. Generally epoch dates don't have any special significance - they just a handy date/time to start counting from. --Bob Mellish 16:03, 16 December 2005 (UTC)
Viewable area in LCD monitors
In CRT monitors, if we feel 13.75 inches (in a 15 inch monitor) as big, it would be possible to adjust the size to say 13 inches. Will the same be possible in a LCD monitor? Can we change the viewable area in LCD monitors and laptops?
- The fact that you don't have to fiddle with the screen size on an LCD is usually considered a feature. Jasongetsdown 19:24, 16 December 2005 (UTC)
(The original asker of the question) Do you mean that it is not possible to reduce the size? Just another query, Is it possible to do that in windows if not in the monitor?
In principle, sort of. It depends on the electronics that are attached to the screen - these are required in a CRT, and not in an LCD, so probably not. On the other hand, a software appraoch would work for an LCD - where you define the outer (say) 100 pixels to be black, and tell the OS not to use them. The only OS I know that supports that kind of wacky configuration is the GNU Hurd - which is very much not a 'suitably for general use' OS. Syntax 02:48, 20 December 2005 (UTC)
I have a definition, but need the word
The definition is:
The property of a substance to retain heat.
I tried to find the answer on google by typing in the definition, but that didn't get me anywhere. I also tried dictionary websites, but I could't find one that would let me find a word by giving the definition.
- Latent heat ?? JackofOz 22:03, 17 December 2005 (UTC)
Lens tissue
What material composes the lens of the eye? What is its index of refraction? While I'm at it, what are the indices of refraction of the aqueous humor and vitreous humor? —Keenan Pepper 21:45, 16 December 2005 (UTC)
- The lens is made–mostly–of crystallins. (There are three families of crystallins: the alpha-, beta-, and gamma-crystallins.) I couldn't tell you refractive indices off the top of my head, however. TenOfAllTrades(talk) 22:04, 16 December 2005 (UTC)
- The eye's lens varies from n=1.406 in the centre to n=1.386 at the edges; as well as its lens shape, it also focuses light by being a GRIN lens. The aqueous humor is n=1.336 and the viterous humor n=1.337. The cornea has n=1.376. All values from Chapter 5 of Hecht's Optics. --Bob Mellish 01:18, 17 December 2005 (UTC)
- Wow! Gradient index optics! I had never even heard of that. And I guess it makes sense that the two humors have the same index of refraction as water, because they're mostly water. Thanks for the great answers! —Keenan Pepper 03:18, 17 December 2005 (UTC)
is matter made of 'light'?
I read somewhere that the basic building blocks of matter where photons at rest, and i think that's kind of silly, but i'm no physcist nor mathematician so i dunno... but it sounds like new age BS.
- That is silly. The basic building blocks of matter are quarks and leptons, as far as we know right now. In ordinary matter, up and down quarks form protons and neutrons, protons and neutrons form nuclei, and nuclei plus electrons form atoms, and different kinds of atoms form molecules. -- SCZenz 23:12, 16 December 2005 (UTC)
- It isn't all that silly... nobody knows what matter is composed of at the most fundamental level. Quarks may be composed of preons, and all our observations may be skewed by symmetry breaking. We have weird theories like superstrings or the single time traveling electron; matter as "frozen light" is tame in comparison if one accepts mass-energy equivalence. The idea doesn't really help to explain the rest of physics, though, so it just amounts to idle speculation. ‣ᓛᖁ♀ᑐ 23:26, 16 December 2005 (UTC)
- Btw, how is that theory called that tries to describe everything (including matter, etc..) only as a fraction in multidimensional space-time? (based on the Kaluza-Klein theory if I remember). helohe (talk) 23:36, 16 December 2005 (UTC)
what would that theory u talk about imply?
- Try theory of everything, if that fails, try ten-dimensional hyperspace, a little bit of a tangent, but worth a look--Aolanaonwaswronglyaccused 16:19, 18 December 2005 (UTC)
December 17
A good way to remove laquer from brass?
I want to do this to a lamp. Thank you for any help.
- A google search for remove lacquer brass returns a lot of hits; one or more might be useful. --jpgordon∇∆∇∆ 03:41, 17 December 2005 (UTC)
Walking Through Walls
This is as much a scientific question as it is a philisophical one, but I was hoping that you could help me find info on something. I read that a long time ago, Chinese monks used to practice the art of walking through walls. I knwo this sounds crazy, but if you have any knowledge of quantum physics then you may be able to grasp this theory. I believe it was once on an old Discovery Channel show, so if you could maybe find an archive of that. I would greatly appreciate any help you could give me on this! Thanks!
--71.33.116.18 02:24, 17 December 2005 (UTC)
- I believe the quantum mechanical concept you are thinking of is quantum tunneling. When you're done reading that look up classical mechanics. The only forces you or I will ever experience are those which obey the laws of classical mechanics. The wierdness of Quantum mechanics can only work for individual atoms or subatomic particles. Electrons can tunnel inexplicably, people cannot. Its still fun stuff though, read up :) Jasongetsdown 02:56, 17 December 2005 (UTC)
- Or maybe these walls were thin and made of paper, like shoji? =P —Keenan Pepper 04:57, 17 December 2005 (UTC)
- Buy the Mr. Tompkins books for a quick overview of quantum mechanics aimed at the casual reader. 82.26.164.168 06:15, 17 December 2005 (UTC)
- Point: Old Chinese monks could most certainly not walk through walls, contrary to the legends. Quantum mechanics suggests that there is a tiny, tiny, tiny chance that such a thing could happen, but beyond that one gets into the fuzzy realm of religion. Which I leave up to you. --George 08:19, 17 December 2005 (UTC)
- To combine the above with what Jasongetsdown said. In dividual particles may move through a wall (then again, what is a wall at that scale?). And people are made up of particles. But they'd have to all do this at exactly the right moment for a something a s big as a human to move through something as thick as a wall. I've heard of an exam question being to do the maths on this. So there is a chance that that could happen but it's immensely small. So I suggest you don't start trying. (Hmmm, didn't I give a similar response earlier somewhere?). DirkvdM 10:43, 17 December 2005 (UTC)
- It's cute to conflate the mystical-seeming logical contradictions of ancient Eastern philosophy with the logical contradictions of modern quantum physics, but the truth is that most feats attributed to ninjas and sects of monks were either feats of strength or slight of hand, which seemed magical to an observer who could not imagine the amount of lifelong training these experts endured. If a monk appeared to walk through a wall, it was probably a feat of misdirection or 'stage magic' on a level probably exceeding David Copperfield or David Blaine, which was put on for the purpose of inspiring the religious faith of observers or else to inspire donations to the temple. -72.144.236.150 06:00, 20 December 2005 (UTC)
Entry into programming
Hi, I was wondering if anyone could recommend some books or web sites that could get me into computer programming, on a very, very basic level. It looks very interesting and I'd like to look into it, but the sections in all the bookstores look very daunting; I wouldn't know where to begin. I'd appreciate your help, thanks. --03:00, 17 December 2005 (UTC)
- Pick something that interests you and keeps your interest. You might want to go for languages with visual interfaces so that you can see your results quickly. --HappyCamper 03:02, 17 December 2005 (UTC)
- Step 1) Pick a language to learn. Scripting languages, such as Python, Ruby and Perl, to name three prominent examples, are especially good for novice programmers. I can personally recommend Python, but Ruby has some momentum behind it, and Perl is an old hacker favourite.
- Step 2) Find resources on your language. There will usually be a resource page on the language's website (look for anything labelled 'beginners' or 'tutorial' or similar), and googling will definetly result in a few good hits.
- Step 2.5) There will be at least one mailing list for newbies. Sign up, try and understand the discussions, and if you get seriously stuck on something, ask a question on there.
- Setp 3) Play around! Nothing beats some practical experience when learning to program. Do any examples in the tutorials you read, try out any little snippets in there, and try and extend them to do more useful stuff. You know all those irritating little tasks that only take about 30 seconds but you have to do constantly? Automate them in your language - you'll be rewarded with valuable experience, and cut those 30 seconds to 5. (Of course, if you're a hardcore MUDder/gamer/sysadmin/etc like my friend here A Lee-Yas, this is probably why you wanted to learn a programming language in the first place :))
- HTH, --Sam Pointon 04:18, 17 December 2005 (UTC)
- I second the recommendation for Python. Look under "Introductions for non-programmers" here: http://www.python.org/doc/Intros.html —Keenan Pepper 04:52, 17 December 2005 (UTC)
- If you are interested in making simple programs as a hobby for Windows, I recommend the Microsoft Visual Studio Express Editions. At the moment they're free and there's lots of help on getting started on MSDN. However, Python, Ruby and Perl may be better for contributing to open-source projects and more complicated applications.
About petroleum
why coal should be use to produce the petrol?
- Are you looking for the Fischer-Tropsch process? 82.26.164.168 06:13, 17 December 2005 (UTC)
Floating
How to people such as David Blain and Criss Angels float in the air???
- It's really simple. They just stand on the edge of one foot, at a certain angle to the camera (or live audience) so you can't see the edge that's touching the ground. The hard part is getting the angle just right, and acting up a storm to distract people from your feet. —Keenan Pepper 04:44, 17 December 2005 (UTC)
- It's called Balducci levitation. —Keenan Pepper 04:45, 17 December 2005 (UTC)
- Indiana Jones came across something similar in the second or third film. DirkvdM 10:45, 17 December 2005 (UTC)
- It was the third film, where Indy must make a "leap of faith" and step into what appears to be nothingness above a huge chasm. But he does step, and when he does finds himself on a bridge painted or carved of stone to look like a cliffside on the other side of the gorge. --Articuno1 01:23, 18 December 2005 (UTC)
- Mind you, the Balducci levitation is just one of the methods magicians can float. David Blaine used a combination of Balducci and standard wire suspension. I'm not familiar with Chris Angel(s). But there's also someone (I believe it was Corey King) who has a method to float which can be viewed from both the front and the back. The best thing to find these things out is to surf the net and forums where people discuss magic or simply visit your nearest magic shop and actually buy the effect (what most people refer to as the "trick"). Also, remember that magic is not just knowing the method behind the "trick", you also need to know how to present it in a way that entertains your audience. - Mgm|(talk) 10:28, 18 December 2005 (UTC)
what are the side effects of divalproex
carbon dating of sea shells & tree fossil.
- See radiocarbon dating. Do you have a specific question? —Keenan Pepper 06:08, 17 December 2005 (UTC)
vitamin pill diet
Hello, this is KeeganB. What would be the danger of going on a diet restricted to vitamin pills and the occasional bit of solid food?
- Possibly bad for the stomach, depending on how much solid food you ingest. This was discovered when a low-weight diet was sought for astronauts. Your tummy needs something to chew on, so to say. Also, vitamins aren't quite the only thing the body needs, so it again depends on the solid food; how much and what does it contain. My advise: stick to a well balanced diet of solid food and throw the vitamins out the window. Along with any other pills, unless you've got some 'disorder'. What is the reason for the question? DirkvdM 10:50, 17 December 2005 (UTC)
- That would depend on just how occasional that "occasional" bit of solid food is, and what it consists of; you would also need to consume water to offset the water lost in urine, perspiration, feces, and expired air. A normal diet consists of much more than vitamins; it consists of minerals, protein, fat, and carbohydrate, as well as vitamins. You need to consume enough calories to maintain your basal metabolic processes, enough of the essential amino acids in protein to maintain lean body mass, enough minerals to maintain skeletal bone density and electrolyte balance. There are also presumably many unknown chemical constituents in normal food that contribute to health. You'd be better off consulting with a dietitian than relying on propaganda from the nutritional supplements industry.--
Mark Bornfeld DDS
Brooklyn, NY 16:08, 17 December 2005 (UTC)
- That would depend on just how occasional that "occasional" bit of solid food is, and what it consists of; you would also need to consume water to offset the water lost in urine, perspiration, feces, and expired air. A normal diet consists of much more than vitamins; it consists of minerals, protein, fat, and carbohydrate, as well as vitamins. You need to consume enough calories to maintain your basal metabolic processes, enough of the essential amino acids in protein to maintain lean body mass, enough minerals to maintain skeletal bone density and electrolyte balance. There are also presumably many unknown chemical constituents in normal food that contribute to health. You'd be better off consulting with a dietitian than relying on propaganda from the nutritional supplements industry.--
- I deliberately didn't mention specific nutrients because the list would be endless, and as Mark says, there are probably also lots of chemicals we need but don't know about yet. Have any experiments been done with people or animals getting a diet of just he things you mention? Of course, this has been done to some extent with astronauts (though so strictly?), but a lack of trace elements and such will probably only have an effect over a longer period of time. I know the Soviet Union did lots of such experiments because they focused on long term stays in space (as a result of which Russia is now considered the expert country for this sort of thing). But did they take it this far (meaning consumption of nothing but water, assorted vitamins, minerals, carbohydrates etc)? DirkvdM 08:51, 18 December 2005 (UTC)
- I agree with the previous comments and would add a few pts:
- Many synthetic vitamins are in forms which are difficult to absorb or use and may actually be of little practical value. For obvious reasons, they don't starve people and just give them vitamin pills to test how effective the vitamin pills really are.
- The full digestive tract needs to be exercised to continue to work properly. Fiber, for example, is important for colon health.
Suicide?
I have heard that some animals, apart from human, do kill themselves.
I want to know
1.It is ture? 2.Why are they doing this? 3.Can you give me an example animal name?
Thanks
- Hmmm, that's going to get quite philosophical. Many social insects readily sacrifice themselves to defend their hive; other social animals will do the same on occasion. Is this suicide? What about salmon, who die after travelling upstream to breed? The example of "animal suicide" you're probably thinking of is the lemming; this myth was apparently spread by a Walt Disney wildlife film.
- Salmon have little choice, I believe. The change happens to them irrespective of what they do (not sure, though). But soldier ants indeed sacrifice themselves for the hive. And some mothers let their kids eat them (again, more common with little critters than mammals). And the reason for that would be (as always) evolution. If one mother had a genetic 'abnormality' that made her let her kids eat her and the kids thus had a better chance of survival, that genetic 'abnormality' might spread and become 'normal' (whatever that is). Of course, if the mother would otherwise have had many more offspring (in other words if other mothers did that and thus got more offspring) then it might not work. DirkvdM 10:58, 17 December 2005 (UTC)
- Whale beaching behaviour may also be suicide, especially since the same whales have been observed to beach themselves repeatedly after being carried back to deep water. For complex creatures, like whales, they may suffer from "brain malfunctions", like we do, that cause human suicides. An evolutionary exlanation is also possible. Old, sick or weak whales, which can't reproduce or contribute to the pod, may kill themselves to avoid consuming food others could eat. Thus, they are helping their genetic relatives pass on their genes more than they could if they continued to live. This may be a concious decision, or they may just have an instinct to swim toward to beach when they feel old, sick, or weak. For most animals, this isn't necessary, as predators or others of their own species will kill off the old, sick, and weak. Sharks might do this, for example. If this theory holds, then suicidal behaviour would be most common in "gentle" animals at the top of the food chain, like whales amd humans (OK, semi-gentle). StuRat 12:47, 22 December 2005 (UTC)
Designing an experiment to show that an increase in temperature infuences the release of red pigment from beetroot. Any ideas???
Any ideas or thoughts would be greatly appreciated. Thanks. — Preceding unsigned comment added by 86.131.123.199 (talk • contribs)
- Seems like a fairly simple homework question. Put some beetroot in cold water and at the same time put some beetroot very hot water and watch to see what happens. --hydnjo talk 14:51, 17 December 2005 (UTC)
Who is E. Duffy
Hello. I was reading biodiesel where I saw "E. Duffy". Does someone know for what does the "E." stand for ? I think that Duffy should not be a redirect but rather a disambiguation page, do you agree ? Thanks in advance--Youssef 11:32, 17 December 2005 (UTC)
- I tried Wikiwax (typed in "Duffy" and waited) and although Wikipedia has two articles on E. Duffy's, neither of them had anything to do with biodiesel. I don't think a disambiguation page should be created, disambiguation pages are not search tools - they exist to navigate between articles that would otherwise share the same title. Ideally we could use the List of people by name, but it needs lots of updating--Commander Keane 11:58, 17 December 2005 (UTC)
About a 15" LCD monitor
Do any one of you use 15" LCD monitor? I just want to know what is the resolution you use. Do you use 1024 x 768? Is it comfortable? And, what is the distance between your eyes and the monitor in the case of a 15" LCD monitor?
- One of the terms you want to look for when picking out an LCD monitor is Native_resolution. This is the resolution that each pixel on the LCD represents one pixel being sent to it by the video card/motherboard. This and many other answers can be found at Liquid_crystal_display. A 04:36, 18 December 2005 (UTC)
- Clarifying the answer above — an LCD monitor is designed to run at one specific resolution (you can read all about it at Native resolution, and unless you have a very good reason you shouldn't run it at any other resolution. For most 15" monitors, the native resolution is 1024x768, however you will definitely want to check your monitor's documentation.
- And as for the distance, that varies from person to person, on how long you use it every day, how good your eyesight is... try and do what feels most comfortable for you, view it at a distance where you can read anything on the screen without straining your eyes or squinting. — QuantumEleven | (talk) 10:21, 19 December 2005 (UTC)
- I'm using a 17 in LCD monitor, but I thought I'd still answer this question.
- LCD monitors have a maximal resolution, on which they can be used optimally. Lower resolutions than this are still readable but don't look nice enough; higher resolutions shouldn't be used. For my monitor, it's 1280x1024 (as this is an 5:4 shaped one), but this wasn't easy to find out. In fact, I looked through the documentation distributed with it a few times, and it definitely wasn't there. (I suppose they think it's enough if the Windows driver they include on the cd knows about it.) The only place this number is written are the advertising documents which lists all properties of the monitor – I had these because I've chosen the type of monitor to buy from them.
- Also note that to get a good image on a TFT monitor, you may have to press the AUTO button of the monitor. I've found that this is only neccessary when I use a certain video mode the first time with the monitor, but pressing again can never hurt. Without using this button, the image can appear sort of unfocused, or some sides of the image can be invisible.
- So, I use 1280x1024 with a 17" monitor and it is very comfortable. The distance to my eyes is usually between 60 cm and 90 cm. Note that there are a few other factors that can affect the comfortability a great deal, like the tilt angle of the monitor; how high you put it (relative to where your head is), the brightness, contrast, and other controlls; and most importantly the lighting conditions of the room (the room should be lit well but you shouldn't see reflections of the lamps or the sun on the monitor). I have strong myopia which is probably why I'm more sensitive to these conditions than most others. – B jonas 13:44, 20 December 2005 (UTC)
water and acetone
can you tell me the method used to separate a mixture of 2 miscible liquids, water and propanone (acetone). The boiling point of propanone being 56 degrees celcius.
Thank you.
- Rotary vap it, after all acetone is a volatile enough solvent that it just boils away at room temperature--Aolanaonwaswronglyaccused 18:17, 17 December 2005 (UTC)
Repairing a Galileo Thermometer
I have broken my Galileo Thermometer but still have the glass spheres. I have tried just putting the spheres in a glass of water but they all just float at the top of the glass, even if i change the temperature of the water. Can anyone tell me what i should use instead of ordinary water and if the glass container should be sealed? Thanks David Spooner.
- Per Galileo thermometer the liquid was probably not water, but an inert hydrocarbon. Perhaps mineral oil? You might try to find and contact a manufacturer and ask what they use. -- Rick Block (talk) 18:48, 17 December 2005 (UTC)
Speach recognition
I would like to open a door latching device by using speach recognition. Any ideas how i can achieve this?--172.201.249.205
- I have actually built one before - albeit a very crude one. Take a recording of your voice, find the Fourier transform of it, and figure out all the unique characteristics of your voice. Then, buy a programmable digital signal processing unit, program it, and attach an output to the door. Takes about 3-4 months to figure out everything if you do this by yourself. --HappyCamper 19:04, 17 December 2005 (UTC)
- Perhaps the article on speech recognition can be of some help. Note the spelling. - Mgm|(talk) 10:32, 18 December 2005 (UTC)
Hypothetical Situation
Suppose there is a spacecraft traveling in space at near the speed of light. On it a person is traveling toward the direction that the spacecraft is moving in. If the combined speed of the person traveling relative to the spacecraft, and the actual speed of the spacecraft is greater then the speed of light, what would happen?
- I'm no expert, but I would guess that all that would happen is that the collision would be equal to the collision of an object travelling at the combined speed of the two spacecraft and a solid object. --Think Fast 18:58, 17 December 2005 (UTC)
- Speeds don't add that way. If the spaceship is moving at speed A relative to Earth, and the person is moving at speed B relative to the spaceship in the same direction, then the person is not moving at speed A + B relative to the Earth. The person is moving at speed where c is the speed of light. If one spaceship is moving at c/2 away from the Earth in one direction, and another is moving at c/2 in the opposite direction, then the speed of the two ships relative to each other is 4c/5, not c. —Keenan Pepper 19:20, 17 December 2005 (UTC)
- Plus the mass of the person would be so great the person would no longer be a person and the spacecraft would have been long since crushed. Hypothetically. Halcatalyst 05:30, 19 December 2005 (UTC)
- Um, no? That contradicts the basic principle of relativity. You wouldn't notice anything different inside the spacecraft, no matter how fast it was moving. —Keenan Pepper 23:44, 19 December 2005 (UTC)
- In human terms, I don't think there would be any "You" in a spacecraft moving near the speed of light. If there had been one when the spacecraft started off, s/he would have suffered the physical effects predicted by relativity theory, which as I recall would include fatal compression on the axis of the direction of travel. But I yield to those who know more than I (a lot of people!). BTW, I was trying to be funny above by injecting a practical objection into a theoretical discussion. Halcatalyst 01:32, 20 December 2005 (UTC)
- I think, actually, that the force you would experience on your body would only be as a result of accelaration, not velocity. If you tried to quickly get to the speed of light, you might crush yourself, but if you're in a closed ship and not subject to air drag, I should think that no matter your velocity, you would be fine. It's just a matter of accelerating at a safe pace. --ParkerHiggins | Talk 01:53, 20 December 2005 (UTC)
- In human terms, I don't think there would be any "You" in a spacecraft moving near the speed of light. If there had been one when the spacecraft started off, s/he would have suffered the physical effects predicted by relativity theory, which as I recall would include fatal compression on the axis of the direction of travel. But I yield to those who know more than I (a lot of people!). BTW, I was trying to be funny above by injecting a practical objection into a theoretical discussion. Halcatalyst 01:32, 20 December 2005 (UTC)
- Um, no? That contradicts the basic principle of relativity. You wouldn't notice anything different inside the spacecraft, no matter how fast it was moving. —Keenan Pepper 23:44, 19 December 2005 (UTC)
- Exactly. You would not be crushed or feel anything different in a ship going near the speed of light, because the basic principle of relativity is that you can't tell how fast you're going. —Keenan Pepper 06:05, 20 December 2005 (UTC)
Ideal and perfect gasses
Is it possible to have a gas with 50% bosons, and 50% fermions, where Fermi-Dirac and Bose-Einstein statistics are simultaneously observed? --HappyCamper 19:08, 17 December 2005 (UTC)
This would only be of observable magnitude with Helium, where Helium-3 (a rare isotope) is effectivly a fermion (as the nucelus has a odd number of fermions), and helium-4 (the common isotope) is effectivly a boson. This is, indeed observable, and is what lead to the discovery of He-3. It's noticable as a difference in boiling points. Something's tugging at my breain about miscability too, but I can't rightly recall. Syntax 03:03, 20 December 2005 (UTC)
Axions
Does the axion have a superpartner or a sparticle? If so what would it be called? The axino? --exomnium
- Well, if supersymmetry and axions both exist, it would have to. There seem to be a few theory papers on this [10] [11], and it does look like it's called the axino, yes. -- SCZenz 22:30, 17 December 2005 (UTC)
Gotta go!
How/why does the sound of running water encourage the urge to urinate? --hydnjo talk 20:01, 17 December 2005 (UTC)
- i guess it has to do with conditioned stimulous and response, like in pavlov's experiment's.
- like , when you urinate, you hear the sound, so you asociate both, and then, when you only hear the water, you asociate it again and the physiological response is triggered.
- ps. sorry for my spelling, english is not my 1st language.
- Sounds reasonable, thank you. --hydnjo talk 01:25, 18 December 2005 (UTC)
Why does dipping a sleeper's hand in warm water cause them to urinate? User:Zoe|(talk) 02:23, 18 December 2005 (UTC)
- Maybe related to the urge to piss in a swimming pool? (Although that doesn't answer the question.) DirkvdM 09:05, 18 December 2005 (UTC)
- Perhaps they think they're wetting the bed? Have you tried this with a representative sample of your sleeping partners, or is it just hearsay? --Shantavira 09:08, 18 December 2005 (UTC)
- The urban legend in the US (re: hand in warm water) is that it makes the person talk in their sleep thus revealing some secrets. ;-) --hydnjo talk 12:50, 18 December 2005 (UTC)
- No, I've never tried it, myself. :) It's something you see all the time in movies and TV shows where teenaged boys are congregated together in sleeping arrangements -- summer camp, school dormitories, etc. User:Zoe|(talk) 00:02, 19 December 2005 (UTC)
- Perhaps they think they're wetting the bed? Have you tried this with a representative sample of your sleeping partners, or is it just hearsay? --Shantavira 09:08, 18 December 2005 (UTC)
That person will feel very relaxed and so the urge to urinate comes. 165.21.83.230Naruto90
I think the theory on the hand in warm water is that it causes the person to think they are back in the womb, where they urinated freely into the amniotic fluid. StuRat 13:04, 22 December 2005 (UTC)
Tryptophan
How and when was tryptophan discovered? Who discovered it? Thanks. --69.165.33.225 20:42, 17 December 2005 (UTC)
- Did you consider doing your own research before posting the question here? I just googled tryptophan and discovered and the answer is in the top ten. may be you could update the wikipedia entry with that info while you are at it? David D. (Talk) 20:48, 17 December 2005 (UTC)
Questions
- 1) In very cold regions, how to very small rodents survive the winter? Do they group together and hibernate? The page on Mice is lacking quite a bit of information.
- 2a) What is heat? Why do particles move faster or slower depending on heat? Why do photons emit heat on impact with other particles? Why does mass shrink or expand depending on heat? (On an atomic level, what is happening when heat is flowing into the system to cause these things to happen?)
- 2b) Since heat is energy, why must energy be expended to cool matter, as opposed to removing energy from the matter? I'm sure that other people have thought of this before -- what is it called? --Demonesque 20:50, 17 December 2005 (UTC)
1) No idea, but I guess they hide in burrows, which keeps them warm and safe enough for hibernation.
- It's hard for rodents and other small mammals to survive in very cold (polar) regions because their bodies dissipate too much heat. Larger animals have an advantage and that's why they're there and the rodents aren't. Natural selection. The permafrost is too close to the surface for burrows. Halcatalyst 05:23, 19 December 2005 (UTC)
- There are plenty of arctic rodents, mostly lemmings and various voles. They survive the winter by tunnelling through the snow cover at ground level; the thick layer of snow protects them from the extreme cold (snow is a very good insulator). The results of the tunnelling are often very conspicuous when the snow thaws in spring, with the tunnels visible from the vegetation having been eaten away - MPF 23:54, 19 December 2005 (UTC)
2a) Heat is essentially just kinetic energy. Particles moving faster or slower isn't an effect of heat - that's what heat is. This also explains matter's expansion. Photons cause heat because radiation contains energy, and that energy has to go somewhere.
2b) What do you mean by 'energy expended'? After all, you can't use up energy. You can't create or destroy it. The concept that is instead important here is entropy. In particularly, the famous second law of thermodynamics, which states that in general, the entropy of a closed system increases. Entropy is in many ways a measure of how close the system is to equilibrium, so if you want to decrease entropy locally by moving a system out of balance - e.g. making one part cooler than another, you have to increase entropy elsewhere. (This is also why there it's comparatively easy to cool down an object that is hot relative to its surroundings.--Fangz 22:28, 17 December 2005 (UTC)
- Um, hibernating animals produce a certian long chain hormone that they can break down to sustain metabolic function, it has nothing to do with the nature of heat or thermodynamics--Aolanaonwaswronglyaccused 23:20, 17 December 2005 (UTC)
Who said it did? I didn't say question one and two were related. Anyway, thanks for the answers. Still not sure about a lot of it, though. I am familiar with the conservation of energy. What I mean is what is happening with heat that particles become "Excited." Why does it expand? Most importantly, though, I'll rephrase my last question. Why does a refrigerator have to be plugged into a wall? Heat is energy, so why must more energy be used in some form to cool the area inside of the 'fridge? Electricity or flame must be used to cool things. This seems counter-intuitive, as the air already has energy in it. Why aren't we working on a way to tap into that energy? If we are, what is it called? --Demonesque 23:34, 17 December 2005 (UTC)
- Gases expand when heated because the excitation of the molecules "pushes" other molecules away. Imagine a group of close packed people, if they start suddenly moving from side to side in a quick manner, the the spaces between the people will increase, I hope that makes sense. As to why we need power to run a fridge, this is because a fridge makes use of a heat pump to cool the air inside it. This means what it is actually doing is taking heat from inside the fridge and putting it outside, thus cooling the air inside. To do this requires a compressor, which needs energy to run. - Akamad 23:54, 17 December 2005 (UTC)
- To expand on what I wrote. In a fridge, we are moving heat from a low temperature area to a high temperature area, since the air inside is cooler than the air outside. This will always require an energy input. Since the natural thermodynamic order of things is for heat to travel from high to low temperatures. As to why we can't use the energy in the air in the fridge: there certainly is energy there (since it is above absolute zero). However, to make use of that energy, we require an even colder reservoir for which the heat in the fridge would want to flow into. Have a look at the Carnot efficiency article. - Akamad 00:07, 18 December 2005 (UTC)
Thank you for your answers and your time. I guess I'm not articulate enough to ask what I want to ask here. I know how refrigerators work and that molecules become "excited." I just don't know WHY they become excited. Maybe no one does?
- There are some very smart people here at Wikipedia. There are also some very articulate people here. You need combination of people who know the answer to the question, can explain it well, and happen to see the question at this place.
- There's a lot of stuff we are able to observe happening in nature. Some can be explained as a general rule "That's how a class of objects function under those conditions." which may or may not be an acceptable answer to "Why?"
User:AlMac|(talk) 08:09, 20 December 2005 (UTC)
To explain why the energy in heat can't be used unless there is a temperature differential, let's look at a potential energy analogy. If you had a weight at the top of a 1000 meter cliff, you could push it over with a rope attached, and use the pull on the rope to power a dynamo during the fall, to get some electricity. Now, if the weight is still at an elevation of 1000 meters, but the ground is uniformally 1000 meters above sea level, with no cliffs, there is no way to turn this weight into energy, even though it still has the same amount of potential energy as in the first example. You could move the weight to a place where there is an elevation difference, but you would likely use more energy moving it there than you would get back, unless a cliff was quite close. Similarly, you need a steep temperature differential where the two temperature regions are quite close to each other to extract more energy than is used up. StuRat 09:45, 22 December 2005 (UTC)
Paranormal
Do any of you know if the 'paranormal phenomena' issue has been settled? I mean, has anyone proven them to exist or not? The reason I ask is that there are a lot of companys and individuals out there that make a buisness out of this. They are all seem to be doing good buisness, so I wonder if there's any truth to these things. (unsigned by User:201.230.73.118 )
- It is just that people like to believe in these things. there is no proof other wise James Randi's prize would have been awarded. David D. (Talk) 21:57, 17 December 2005 (UTC)
- Hard question to answer. Who "proves" these things? Who "proves" that faith in God is not a waste of time, or is? "Paranormal" covers a lot of ground, and includes phenomena, or alleged phenomena, that science cannot explain. Science has dismissed a lot of so-called evidence as flawed, hence does not admit that such phenomena have occurred to begin with. I think you need to examine each phenomenon individually and ask questions about it, rather than lumping all paranormal stuff into one basket and asking whether it's true or not. JackofOz 21:59, 17 December 2005 (UTC)
- The question is somewhat tautological. If a paranormal event gets proven, it instantly becomes just a normal part of science. --Fangz 22:17, 17 December 2005 (UTC)
- Hear hear! —Keenan Pepper 00:26, 18 December 2005 (UTC)
It is usually impossible to prove a negative, to prove that there is no such thing. I cannot disprove the existence of the tooth fairy even though I strongly suspect she doesnt exist. Clearly no one has proven that what you probably mean by "paranormal phenomena" exist. I can imagine lots of ways to prove the existence, but I confess I cannot think of a way to disprove the whole category. What do think such a proof would be like? alteripse 00:01, 18 December 2005 (UTC)
- I believe that in order to call something a theory it has to make predictions. So 'if this is true, then under these conditions such and such must happen'. And if it isn't even a theory then science can't do anything with it. Also, an experiment has to be described in such a way that other scientists can repeat it completely separately. Now 'paranormal' can mean loads of things, but let's take a psychic who conjures up spirits or whatever. Then scientists at the other end of the globe have to be able to do exactly the same experiment. But for that they'd need the original psychic, which would mean it's not an independent experiment. DirkvdM 09:17, 18 December 2005 (UTC)
- That sounds like a scientist's way of saying that this particular experiment is inherently unprovable. But at least that's not as extreme as saying that such a phenomenon does not exist because science has not given its imprimatur for it to exist. A T Mann, at p.63 of "The Divine Plot" says: "... scientists assume that 2 experiments can produce the same quantitative results, but they cannot, because the circumstances can never be exactly reproduced, nor can external influences be eliminated. The earth moves hundreds of thousands of miles through space and time every day in the movement of the solar system through time. Reproducability is a central fallacy of modern science ...". Science is one way of considering and explaining the universe. It is not the only way. Seems that paranormal stuff like ESP is regularly debunked by the Randis of the world, on the basis that nobody has proven scientifically that it is real. But maybe that's the point. Maybe it's simply outside what science can grapple with, but is nonetheless very real. By staring at the back of a stranger's head, I can make them aware that I'm looking, or at least feel uncomfortable. I have done it at various times in public transport just to prove to myself that it happens, not because I'm some sort of malicious weirdo. Science would say there is nothing connecting me with that person, but I would say that I know and the other person knows there is. Science could never prove this to the satisfaction of its internal criteria. It occurs nonetheless. JackofOz 08:56, 19 December 2005 (UTC)
- Rubbish. Science doesn't make any such assertion about whether or not your 'effect' is real. Science demands that before you claim it is real, you put this ability to a rigorous test. For example, the following experiment would easily net you the 1 million dollar prize:
- Get a group of students. Don't tell them why they are there. Randomly select 2 groups of around 20 each. Now, sit them in a two rooms watching a movie. Now, in one room, have an experimentalist sit behind the students, staring at the back of their heads. In another, have you staring at the back of their heads. Have them write down their feelings afterwards. If a significantly higher number record feelings of being watched, then you get the money. Otherwise, it's just aphonenia. If you demand a 1-to-1 relationship, then have them watch movies 1-by-1. If you think the process is affected by stellar position, or whatever, then do it as the times you usually use the bus. If you think the bus angle is important, have them watch movies of a bus journey, or get questionaires done after they get off buses, and compare with a control set. And so on. The fact that you have 'done it at various times' is a claim of reproducibility, and it puts you into the firing range of scientific methods.
- If Mann is at all right about his assertion, then he would disprove Relativity and create a huge number of paradoxes. If an effect is that sensitive to 'external events', then science wouldn't be alone in not detecting it. After all, science is just an analytical system. If it happens often enough to be noticeable in the first place, then science will certain work with that degree of reproducibility.--Fangz 12:10, 19 December 2005 (UTC)
- Rubbish. Science doesn't make any such assertion about whether or not your 'effect' is real. Science demands that before you claim it is real, you put this ability to a rigorous test. For example, the following experiment would easily net you the 1 million dollar prize:
- You said: "Science doesn't make any such assertion about whether or not your 'effect' is real. Science demands that before you claim it is real, you put this ability to a rigorous test." Doesn't the 2nd sentence negate the 1st? Isn't the 2nd sentence saying that science only accepts as real those things that have been proven to be real using scientifically rigorous tests? This supports the point I was making. I am not a critic of science, but neither do I reject paranormal claims out of hand. If some phenomenon currently considered "paranormal" were to become scientifically proven, then it would no longer be called "paranormal" and its reality would no longer be questioned. But just because science has not yet proven a particular phenomenon is real, does not necessarily mean that it is not real already. Science is not the final arbiter of reality. Hamlet had it right, I think: "There are more things between heaven and earth, Horatio, than are dreamt of in your philosophy". (Philosophy here referring to knowledge, or science) JackofOz 01:52, 20 December 2005 (UTC)
- Part of the definition of Science is that some experiment or process can be written up in detail, then some totally independent group of people repeat the experiment and get the identical results.
- With paranormal phenomena, it would appear that some people have some abilities, from whatever sources, perhaps genetic, such that they do something, and no matter how their actions are documented, other people who lack that genetic ability are not going to be able to duplicate the process.
- Further, the alleged phenomena is something that cannot be explained by the people observing it. It is not that they used scientific method working with some theory and experiments to polish an understanding. Rather, something weird happens, like in a dream we see something, and we think it is just a dream fantasy, then later we see same thing happen in reality. Well was the dream some kind of clairvoyance? How can we tell when a dream fantasy is a prediction, and when just a fantasy? This sort of thing is just one person's word and interpretations, like sighting a UFO or having a religious experience, far too subjective to be called Science. User:AlMac|(talk) 08:17, 20 December 2005 (UTC)
- There's still this hang up with what science has to say about paranormal phenomena. You're all talking as if science were the only paradigm that could ever possibly be relevant. The original question was not whether paranormal phenomena have been proven scientifically, but whether they have been proven. OK, that kind of begs the question, how is something "proven" if not using a scientific method? Fair question, and not one I can answer. Paranormal phenemona by their very nature are, or can be, extra-scientific, so we need a "bigger picture" frame of reference here. My original rhetorical comment was about faith in God and who could ever "prove" this was justified. Science could never in a billion years settle that question one way or another, but there are billions of people for whom there is no possible doubt about faith in a supreme being, and for whom no "proof" will ever be necessary. The effects of prayer and faith have been voluminously documented over many millennia. Witness the 70-odd miraculous cures with the water from the spring at the grotto of Lourdes, which have been rigorously and exhaustively documented and subjected to the most extreme scientific and medical scrutiny. Science can't explain how these cures occur, which puts them into the category of paranormal. But there's no possible doubt as to their veracity. JackofOz 11:19, 20 December 2005 (UTC)
- Further, the alleged phenomena is something that cannot be explained by the people observing it. It is not that they used scientific method working with some theory and experiments to polish an understanding. Rather, something weird happens, like in a dream we see something, and we think it is just a dream fantasy, then later we see same thing happen in reality. Well was the dream some kind of clairvoyance? How can we tell when a dream fantasy is a prediction, and when just a fantasy? This sort of thing is just one person's word and interpretations, like sighting a UFO or having a religious experience, far too subjective to be called Science. User:AlMac|(talk) 08:17, 20 December 2005 (UTC)
- Question "How is something "proven" if not using a scientific method?"
- Answer = One way things can be "proven" outside of a scientific method, is through the court system, provided someone brings a case, and it is not thrown out by a judge.
- All sorts of people make claims, such as commercial claims about cosmetics, faith healing, spiritualism, and all sorts of people complain that those claims are bogus. User:AlMac|(talk) 02:15, 21 December 2005 (UTC)
Court "proof" is a really low standard, as it comes down to whatever a judge and/or jury, a small number of often not-too-bright people, believe. Court verdicts are often wrong as a result. Note that the existence of God could easily be proven by a personal appearance, or even a few of the Biblical miracles, like the parting of the Red Sea on a holy man's command, would be sufficient to convince most of us. The lack of such levels of proof since the dawn of science seems mighty coincidental to me. As for sudden cures, there are many explanations:
1) Many diseases do go away, or at least go into remission, spontaneously, both for those who believe in miracles and those who don't. I used to have plantars warts (on the feet), then they went away. Had I been a religious fanatic, I could have said the chicken whose head I bit off was what cured me.
2) Many diseases are subject to the "placebo effect". Arthritis, for example, is measured primarily by the amount of pain reported. If someone thinks they are cured, either by visiting Lourdes or by biting the head off a chicken, they may convince themselves the pain level is reduced or eliminated.
3) There are also shills who are willing to pretend they were sick and then cured, either for money or just for fame.
4) Then there is just the gap in media coverage. The millions of people who visit Lourdes and don't have any "miraculous cure" rarely get much press. This makes it seem that the few who do report a cure are 100% of the people who went, because we never hear about the rest.
I believe many of the paranormal claims have been disproven. For example, the "cold reading" methods used to convince people a particular "pyschic" has a connection with the dead can be easily replicated by anyone who spends a few hours studying the technique. For example, when someone points to a part of the audience and says "I'm seeing someone over here whose name starts with a J"...the chances that one of the 100 people in that general area will have a first, middle, or last name starting with J, or have some dead relative with a first, middle, or last name that starts with J, is probably in the 99.999% range. Yet, when somebody says "that's me !" they are absolutely sure the "pyschic" has proven his "gift" and are ready to hand over their life savings to them. It's hard to believe that the dead person is only able to tell the pyschic the first letter, and not the whole name. It also seems odd that no dead person ever tells the pyschic his name starts with a rarely used letter. Dead Quincy, Xavier, and Zachary apparently lack the ability to communicate with pyschics, LOL. StuRat 09:06, 22 December 2005 (UTC)
StuRat 09:06, 22 December 2005 (UTC)
Conway's life computer
Has anyone made a computer in a Conway's life simulation?--Shanedidona 23:59, 17 December 2005 (UTC)
This reference from Conway's life:
- A Turing Machine in Conway's Game of Life (.pdf file) - Paul Rendell
describes how a Turing machine can be made in the "life" simulation. --JWSchmidt 00:11, 18 December 2005 (UTC)
December 18
Christmas Debts
Christmas is coming. People in the U.S. are burying themselves in debts.
- http://www.nytimes.com/2005/12/11/national/11credit.html
- http://www.mezomorf.com/emailed/news-15976.html
- December 11, 2005
- Newly Bankrupt Raking In Piles of Credit Offers
- By Timothy Egan
- ... Ms. Fogle is broke, ... she had no sooner filed for bankruptcy, ... than [sic] she was hit with a flurry of solicitations from major banks. ... "Every day, I get at least two or three new credit card offers ... at pretty high interest rates,"
- ...Credit card companies have long solicited bankrupt people, on a calculated risk that income from the higher interest rates and late fees paid by those who are trying to get their credit back will outweigh the losses from those who fail to make payments altogether.
What? Is this the whole story? Where do the late fees and interests go? Do they become a part of the banker's profit immediately? Or are they used to write-off the debt as well? I think most, if not all, late fees and interests go to the banks. Am I right?
Let's say there are two banks, each lends the same money to customers at the same interest rate.
- Bank A: Reliable customers. They pay back the debts on time. And they come back again when they need money.
- Bank B: Unreliable customers. Most of them pay the minimum. Some pay old debts with new debts. Some go bankrupt.
Because the interest rates are the same. You can say they make roughly the same money each year if the interests directly go to the bankers. Only Bank B has a much lower turnover rate.
In theory, the bank's money comes from depositors. The depositor shall get the money back. So the bank needs to collect the profit and the seed money as well. However, ...
- Bank A: The bank makes easy money. Its depositors are safe.
- Bank B: The bank makes easy money. Its depositors are taking all the risks.
It seems to me in the case of Bank B, the bank takes almost all the profits and very little risk. The risk goes to the depositors. If the bank goes bankrupt in a decade, that's not today's managers' problem. They'll be retired by then. Am I right? Is my theory applicable to the fact? -- Toytoy 04:55, 18 December 2005 (UTC)
- Bank depositors in the US aren't really under any risk. See FDIC. Night Gyr 11:31, 19 December 2005 (UTC)
- This is in no way a problem limited to the banking industry. Making short-sighted decisions designed to increase quarterly profits at the expense of the long-term health of a company would seem to be in the interest of many CEOs. For example, selling off the most profitable divisions for immediate profits, leaving the company saddled with unprofitable divisions, would serve a CEO who has a bonus structure based on current profits only. The only limiting factor is that SOME shareholders do have the long-term interest of the company in mind, especially employee shareholders. If they can manage a majority, they can fire such a CEO before he does too much damage to the company. Of course, if they again offer pay based strictly on short-term performance to the next CEO, they are likely to get the same result. StuRat 08:27, 22 December 2005 (UTC)
what is this brain-related(?) phenomenon called?
So a couple nights ago, after playing Wave Race 64 for what must have been 5 or 6 hours almost nonstop, I went to bed. However, the patterns of the waves in that game, rapidly undulating up and down, would keep "playing" in my mind, like an uncontrollable looping video, making it hard to sleep.
First off, does this phenomenon have a name? Second, is it related at all to how when you hear a catchy tune, for whatever reason it keeps playing in your mind even when you try to think about something else (damn you, Pink Floyd!) and it effectively messes up your concentration or sleep also? --I am not good at running 07:42, 18 December 2005 (UTC)
- Hypnagogia. —Keenan Pepper 08:16, 18 December 2005 (UTC)
- Hypnagogia is a bit much for this, don't you think? This appears to be a common case of overstimulated nerves. It is like riding on a motorcycle all day and feeling the rumble of it all night or wearing a hat for hours and then feeling it on your head long after it has been removed. Some nerves are very sensitive to overstimulation - especially the cones in the eye. After being stimulated, they continue react when the stimulus is removed. The brain just responds to the nerves. So, after stimulating various nerves in the body all day and then removing the stimulus, the nerves continue to react and signal the brain. If you want to get really scientific about it - the nerves are actually having a negative reaction. They are sending a signal that the stimulus is not there. But, for something like motion, moving left right left feels about the same as moving right left right. --Kainaw (talk) 16:58, 18 December 2005 (UTC)
- I think what you just described is an afterimage, and those don't last more than few minutes. —Keenan Pepper 19:30, 18 December 2005 (UTC)
- Correct. Afterimage occurs in the optic nerves. They are easily stimulated and quickly get over it. Nerves that are harder to stimulate will have the afterimage effect much longer. --Kainaw (talk) 13:49, 19 December 2005 (UTC)
- I think what you just described is an afterimage, and those don't last more than few minutes. —Keenan Pepper 19:30, 18 December 2005 (UTC)
- Somewhat related, the McCollough effect (external link), which I find mildly freaky. A simple pattern which affects your visual system for hours or days! Maybe there's a similar visual memory regarding motion, beyond the usual "waterfall illusion"-type motion aftereffects. Femto 14:40, 19 December 2005 (UTC)
- This is blowing my mind! It lasts so much longer than an afterimage! You turn your head and the colors magically switch back and forth! —Keenan Pepper 06:21, 20 December 2005 (UTC)
- Told you it's freaky. =) Femto 12:17, 20 December 2005 (UTC)
- I've noticed that some time after cross country skiing, my walking motion is more like skiing. It takes a while to "switch back" to normal walking. StuRat 08:07, 22 December 2005 (UTC)
Can a Boeing 777 use a ram air turbine?
Can a Boeing 777 be built/use/retrofitted with a ram air turbine? I read the article on the 777 and it did not state whether or not the 777 can use the RAT. --Blue387 07:52, 18 December 2005 (UTC)
- The answer appears to be yes: [12]. --24.31.29.171 08:39, 18 December 2005 (UTC)
Coffee - water temperature
Coffee#Brewing says that coffee should ideally be made with water at 93 C. I use the first method under 'boiling'; I put the ground coffee in a cup and pour boiling water on it. Now boiling water is 100 C. But I assume that during the pouring the water will cool down fast. But it would have to 'loose 8 C' over a distance of about 10 cm. Of course this is more complicated, because the cup will cool it down even faster, but then the ground coffee will have already been in contact with hotter water and I don't know how how bad that is. But could someone with a good thermometer test this? Pour boiling water and measure the temperature at various distances? And, alternatively, pour the water in a cup and measure the change in temperature. Of course this would require a very fast-acting thermometer, and preferably an electronic one. But I believe those exist (well, I know they do, but are they fast enough?). DirkvdM 09:35, 18 December 2005 (UTC)
- This does not a question make. Seriously, it's difficult to figure out what your asking. Are you worried that coffee prepared in a cup will cool faster than in a pot? In any event it is not a concern, I know that pouring water in a cup to prepare something, say ramen noodles doesn't cool until some time after they are ingested.--Ridge Racer 15:06, 18 December 2005 (UTC)
- I thought the question was quite clear. I want to know at what temperature the water is when it hits the ground coffee, because ideally it should be 93 C. How to measure that is the problem. Especially if you don't have the right thermometer, so that's why I made that bold. Just a simple experiment for someone with the right equipment. DirkvdM 08:11, 19 December 2005 (UTC)
The water should not be at 93 degrees. Water that hot will burn the coffee. That is why professional baristas use thermometers when thay make coffee. Especially, if you are making a latte, cappucino, or flat white, the milk should not be heated above 65 to 70 degrees before it is poured into the espresso. Milk protein scalds at around 70 degrees. Many people like their coffee to be very hot. In that case the cup can be preheated with 90 degree (or so) water. A digital thermometer is pretty inexpensive, about $15, and will give you a nearly instant read ---Rupee
premature grey hair
What are the reasons for premature grey hair ? What is the medical solution for it ? 59.94.96.77 09:43, 18 December 2005 (UTC)Tina
- 1) Genetics. 2) Hair dye, if you want to disguise it. Ever wondered why Chinese people don't go grey? Expert use of hair dye. See this BBC article.--Robert Merkel 11:14, 18 December 2005 (UTC)
See hair color for some details. alteripse 14:26, 18 December 2005 (UTC)
- I would argue with the term "premature greying". We have this concept that people, especially women, don't get grey hair until they are elderly. This misconception is reinforced by the media and the extensive use of hair dye, when, in reality, middle age is when most people start to grey, and many start earlier on. I had my first grey hair at 18 (right after I started drinking cofee, I wonder if there is a relationship). StuRat 13:09, 22 December 2005 (UTC)
the speed of light
what is the speed of light
- Why, it's how fast light moves!
- Just kidding. It's all there at Speed of light --ParkerHiggins 10:15, 18 December 2005 (UTC)
- Also, c, it's programmed into google's scientific calculator function--Aolanaonwaswronglyaccused 16:10, 18 December 2005 (UTC)
CPU clock rate and performance
1. What is good (accurate, easily obtainable) indicator of processor performance (speed), today?
Until some time ago, we used CPU clock rate ("megahertz") to gauge processor performance (speed), and it seemed pretty accurate too. However, I think gauging CPU performance solely based on its clock doesn't seem to be relevant today, as most processor manufacturers starting to remove CPU clock (at least from product names), and I heard many benchmarks resulting in CPU with lower clock rate outperforming CPU with higher clock rate.
- Read benchmark (computing). There's no way to give a specific answer to your question without knowing what kind of work you wish to do with your processor. --Robert Merkel 11:10, 18 December 2005 (UTC)
- A clock tick tells the computer to start changing to the next stable state. Put more clearly, one instruction is performed per clock cycle. But that leaves the question how big an instruction is. Because different architectures (with different size instructions) started to compete on the market, the clock rate was no longer a good indication (walking for ten minutes doesn't get you further than running for five minutes, so to say). Anyway, the processor speed (however measured) is overrated. It's a good rough indication, but other parts of the computer can matter a lot too, depending on what kind of work you want it to do. Fort example, if you need to do a lot of graphical work (like movie editing) then a graphical card that takes some load off the CPU's back will help more than a faster CPU (being a fast runner doesn't help a lot if you need to cross water (unless you're a jezus christ lizard - or indeed the guy himself :) )). But there are many more aspects, indeed too many to mention here. DirkvdM 08:49, 19 December 2005 (UTC)
2. Why the growth of CPU clock rate is not as fast as a few years ago? Are we approaching some kind of limit? 61.94.149.220 10:20, 18 December 2005 (UTC)
- A combination of physics and economics; notably, as I understand it the speed of light is becoming an issue. Say your processor is running at 3.2 GHz. That means one cycle takes seconds. Light (and no signal can be transmitted across the chip faster than light, generally electric currents are significantly slower) travels at approximately metres per second. That means that in one clock cycle, light can only travel a bit under 10 centimetres, and electric currents a bit less than that again.
- But as processes continue to shrink, you've got all that extra space on your CPU die; how do you take advantage of it? Well, what AMD and Intel have done is whack a second CPU inside the one physical chip; it's the easiest way to take advantage of the space, and seems to improve performance a lot more than using the space for more cache would. --Robert Merkel 11:10, 18 December 2005 (UTC)
- So in order to increase speed you need to make the CPU smaller, but now the limits of the present technology (the materials used) are approaching the limits (although that has been said before and workarounds like Robert mentions have circumvented the problem). The size of the conduits are approaching molecular levels. So different materials and signal carriers (like light) are being researched. I can't find an article on this, though. Surely there must be one (a technical subject (computer related even) that is not covered by Wikipedia? Impossible! Right?). DirkvdM 08:49, 19 December 2005 (UTC)
- Optical computer. Da daaah! Proto t c 10:48, 20 December 2005 (UTC)
- As well, CPU's are burning up as all those moving electrons get packed into a small space. Intel is dying with this right now. AMD and Sun are trying other methods to increase memory throughput. --Zeizmic 15:23, 21 December 2005 (UTC)
computer hard disk
if i connected two hard disk to my system them onlu one har disk is activated why this
then same thing two hard disk and my operating system in second hard disk at that time from which hard disk system gets boooting email removed
- What operating system do you use?--Ridge Racer 15:08, 18 December 2005 (UTC)
- Did you check to make sure the jumper pins are set correctly? Proper master/slave settings are necessary - I think. --HappyCamper 15:09, 18 December 2005 (UTC)
- Most PCs have two IDE connectors. The Operating system usually looks for the first harddrive on the first IDE connector. What is not explained in the question is: Are they IDE drives? Are they using the same cable? Have the jumpers for Master/Slave/CS been changed? Is the new harddrive formatted? If so, is it a format readable by the OS?
- Usually, just setting all drives to CS (cable-select) will fix the problems. --Kainaw (talk) 16:50, 18 December 2005 (UTC)
- Did you check to make sure the jumper pins are set correctly? Proper master/slave settings are necessary - I think. --HappyCamper 15:09, 18 December 2005 (UTC)
Chemistry Question: Chloroform-like Anesthetic?
In writing a chapter in an ongoing fantasy story, I've come across an interesting opportunity to link a present event to a future character (an alchemist, among other occupations) that will eventually make an appearance.
But in order to avoid a too-obvious deus ex machina, I'd prefer using an actual substance that can be isolated solely through repeated distillation or other relatively simple chemical processes, which has incapacitating properties more-or-less identical to that of chloroform as it is commonly (and inaccurately) portrayed on network television shows.
Any assistance would be appreciated. --The Confessor 15:23, 18 December 2005 (UTC)
- Try halothane, isoflurane, sevoflurane and desflurane, which are listed as Inhalational anaesthetics. All of them may not be produced very easily/readily, but I'm sure your character would have no trouble obtaining some.--Ridge Racer 15:42, 18 December 2005 (UTC)
- Personally, I'd go for Nitrous oxide. Simpler of all the compounds. --HappyCamper 17:22, 18 December 2005 (UTC)
- NOS effects are disassociative. Incapacitating, but not so as to produce unconsciousness... and thus unsuitable for this plot element. --The Confessor 17:44, 18 December 2005 (UTC)
- Pretty damn close to unconsciousness, for what it's worth. But what about ether? Easy enough to make (distill ethanol and sulfuric acid). General anaesthetic. --jpgordon∇∆∇∆ 18:15, 18 December 2005 (UTC)
- Does anybody else think it's a bad idea to assemble a list of easy to purify, volitile solvents, that could be used to render someone unconscious? (: Oh and ether would boil away too fast I think--Aolanonawanabe 19:42, 18 December 2005 (UTC)
- You mean a list like that on wikipedia? Sounds cool to me, but reminds me of The Manual of Crime over at wikibooks, which sadly was deleted.--Ridge Racer 20:49, 18 December 2005 (UTC)
- That was simply a loaded question. Realistically, any content on Wikipedia can be construed as "dangerous". The mind is abstract enough to do this if it wanted to. --HappyCamper 23:06, 18 December 2005 (UTC)
- Nope, ether works just fine and in fact used to be kept in little bottles in doctors kits for the express purpose of being an easy-to-administer general anasthetic (just put it on a rag and inhale it). -User:Lommer | talk 23:51, 18 December 2005 (UTC)
wavelength
i would like to know what is the frequency and wavelength emitted by an ordinary tubelight or an lamp?...........
- You should be able to derive this from the color of the bulb using this as a standard --Aolanonawanabe 18:35, 18 December 2005 (UTC)
- Tube lights typically have very narrow spectral bands rather than a gradation of light throughout all frequencies. In other words they are not like sunlight. So the question is what is ordinary? In fact there are many different tube lights that have different light qualities. Some are more red, others more blue and others a mix of all colors, so called full spectrum. Check out this page for some typical spectra. David D. (Talk) 19:52, 18 December 2005 (UTC)
- Is "tube light" British Engish for a fluorescent light ? StuRat 07:51, 22 December 2005 (UTC)
burning cd with more than 2 gb data
how to burn a cd of 700 mb with more than 1 gb to 5 gb fo data in it. i saw a cd windows 2003 pirated 10 in 1 with 4.7 gb of data in it....
- The maximum raw capacity of a CD-ROM varies; some can actually store up to about 912 megabytes of data. Data compression can allow data to be "squeezed" into a smaller amount of data, and expanded to its original format when desire. However, in most cases, data distributed on CD's is already distributed in compressed form. I suspect what you actually saw was a DVD-ROM. DVD-ROM is so cheap and ubiquitous nowadays you wouldn't bother trying anything else.--Robert Merkel 21:42, 18 December 2005 (UTC)
- For such high amounts of data, I would recommend a DVD-ROM as well. There's no way 1-5 Gb is going to fit on a regular CD-ROM. - 131.211.210.10 08:29, 19 December 2005 (UTC)
- Of course, a DVD with hacked software would probably not be a DVD-RAM, but a writeable DVD, but it redirects, so above link still works. DirkvdM 08:54, 19 December 2005 (UTC)
- 4.7 GB is the standard capacity for a DVD, so what you probably saw was really a mislabeled DVD. Night Gyr 11:18, 19 December 2005 (UTC)
Circuitry question
I was hoping to build this circuit of an analog synth. It's very simple, I understand, but I haven't done much building in my career. I have a question with the inverter number CD40106, and it's ___location on the circuit. Part UI-A (which I think is two of the prongs on the 14 prong inverter) appears to have four connections to it. It looks like two go off to resistors, and one goes to a power, and the other goes to a ground. I don't know how that works, or how to wire that.
I have a picture of the part of the schematic in question, but I'm not sure if I can upload it for copyright reasons. I'd be perfectly happy to provide any more information if it would help! --ParkerHiggins | Talk 22:25, 18 December 2005 (UTC)
- That is the standard way to draw the power connections to an IC that contains multiple logic gates. U1 is a hex inverter, and all six inverters in the package share the same two power pins on the IC - pins 7 and 14. (Note: 'pins', not 'prongs'.) To save space, we always draw five of the inverters without any power connections, and one with them. In this case, they have drawn the power pins attached to the inverter with its input on pin 1 and its output on pin 2. All you have to do is wire up pin 14 to the positive supply and pin 7 to the ground, and all six inverters will then work. --Heron 23:01, 18 December 2005 (UTC)
- Good answer Heron, looks like I shouldn't have taken so long to answer the question after starting the edit. A 23:13, 18 December 2005 (UTC)
- You are right, U1-A is part of the same chip as U1-B and U1-C. The extra conections you see in U1-A that are absent from the others are for power (pin 14) and ground (pin 7). Common convention states that you should include these pins on one of the device elements, U1-A in this example, as they do need to be connected for the chip to work, but not all of them. A 23:11, 18 December 2005 (UTC)
- Oh man, you guys are lifesavers! Just to clarify, there is no distinction as to which two pins are 7 and 14, right? I mean, they're on one end, but doesn it matter which end, or is there any way for me to tell which end? Thanks! --ParkerHiggins | Talk 23:56, 18 December 2005 (UTC)
- To rephrase that question, is there a standard system of pin numbering? For example, it seems reasonable to me that U1-A, for example, would refer to a set of pins opposite each other, as would the power pins, 7 and 14. Shouldn't the connections from U1-A be labeled 1 and 8, then, not 1 and 2? Also, is there any distinction between pins 1 and 8 and pins 7 and 14? If I flip the inverter over, there's no telling which is which! If it would help answer this question (I know I'm throwing a lot of arbitrary numbers around) I can photograph the component itself. --ParkerHiggins | Talk 07:42, 19 December 2005 (UTC)
- If it's the usual sort of DIP package, one end will be marked with a U-shaped notch or depression. Since it's got 14 pins, holding the notch uppermost and looking at the labelled side, the pin numbers will run 1-7 down the left side, then 8-14 up the right side. Thus the power pins will be the bottom-left and top-right pins. If there's no notch, usually pin 1 is marked with a dot.
- For example, our picture at Image:DIL14 IC HCF4093.jpg is a 14-pin DIP. You can see the notch at the top left. The pins we can see will number 1 to 7 from the left to the right. The pins we can't see from this angle with run 8 to 14 from the right to the left. --Bob Mellish 15:33, 19 December 2005 (UTC)
- Aha! So that's the page I was looking for. It's actually, I think, the same DIP in that picture. Or at least very similar. Thank you! --ParkerHiggins | Talk 15:35, 19 December 2005 (UTC)
- If you are ever in doubt about the pin numbering of a common device like a 40106, just go to the website of a mail order electronic components company like http://www.maplin.co.uk. They have a page of information called a data sheet on every device they sell, including the 40106 (PDF here), that includes a picture of the gates with pin numbers. Happy constructing! (And no, I don't work for Maplin.) --Heron 20:42, 19 December 2005 (UTC)
December 19
The See Clearly Method
I was wondering if anyone could answer the question of wheather the "See Clearly Method" works. The "See Clearly Method" has been advertised as being able to correct a person's vision naturally without the use of a new perscription for ones eyeware. I was also wondering how it actually works? If it does what are its limits, etc?
- Pure bullshit. Anyone can become a doctor and advertise as such these days. Generally speaking it lists treatment as eye exercise, diet/nutrition, and a low stress lifestyle. This might help slightly blurry vision if you have malnutrition or stress, but trust me, if your eyesight requires prescription glasses, you can't fix them for $9.95. Also, quoted from the site, * This self-assessment should not be used as a substitute for the medical diagnosis and treatment of your vision, nor should the See Clearly Method be a substitute for diagnosis or treatment by an optometrist or ophthalmologist. Before using the See Clearly Method, you should consult with an optometrist or ophthalmologist to determine if any eye disease or other condition requiring specialized treatment is present.--Ridge Racer 03:05, 19 December 2005 (UTC)
- Yes, but they are counting on the fact that their potential customers can't read that fine print. LOL. StuRat 05:20, 22 December 2005 (UTC)
- We have articles on this sort of thing, but they're not very prominent. Bates Method is similar pseudoscience for natural eye correction. Night Gyr 05:55, 19 December 2005 (UTC)
- Yes, it's pure quackery. Neutralitytalk 06:18, 19 December 2005 (UTC)
- Perhaps it could help you see clearer when the correction needed is very little (less than minus 1). Anything higher is not going to be correctable with mere excercize. Making your eyes strain to see properly is more likely to tire them than anything else. - 131.211.210.10 08:33, 19 December 2005 (UTC)
Ciliary muscles
Are the ciliary muscles the only smooth muscles that can be controlled voluntarily? —Keenan Pepper 03:50, 19 December 2005 (UTC)
I don't think one can voluntarily dilate their own pupils, which is what you seem to be suggesting. Nrets 16:58, 19 December 2005 (UTC)
- The ciliary muscles do not dilate the pupils, they change the shape of the lens to focus on near or distant objects. (The other muscles are called, logically enough, iris dilator muscles.) I can voluntarily make my eyes go in and out of focus, which seems like I'm voluntarily contracting and relaxing my ciliary muscles, but I could be wrong. —Keenan Pepper 21:14, 19 December 2005 (UTC)
Six Kingdoms and Microbes
I've heard that there are six kingoms of living things in the world: animals, plants, fungi, protists,eubacteria and archaebacteria.But what about microbes?I've about heard that apart from animals and plants the other type of living thing that exists is microbes.So why haven't biologists classified microbes as a single group of living things?
- Believe it or not there is more genetic diversity among microbes than there is among plants and animals. The eubacteria and archaebacteria are the current kingdoms that describe prokaryotic microbes. I guess protists could be described as microbes (assuminjg you are using the general definition of small) but they are definitely eucaryotes and so are not grouped with the prokaryotes. Not all fungi are microbes. Some fungi are the largest organisms on earth. You can't see them as they are in the soil but they can be as large as 15km2 in area. David D. (Talk) 04:24, 19 December 2005 (UTC)
- Single-celled plants and animals might also be called "microbes", if going strictly by size. StuRat 05:17, 22 December 2005 (UTC)
- Here is another link that might be useful: Kingdom (biology). David D. (Talk) 04:31, 19 December 2005 (UTC)
- In other words, the term microbe is about size, it is not a taxonomy classification. And the number of kingdoms is also reason for dispute. A logical ordering wqould seem animals, plants, fungi and bacteria. But that's anthropomorphic. Along the lines of what David said, there is more variation among bacteria than among the other classes, so those should be grouped together, as Woese does, who introduces a third 'class', Archaea, based not on looks but on genetics (which makes more sense). Archae would by looks be classified as bacteria, so basically there's bacteria, bacteria and Eukaryotes, which include animals. We animals are just a speck in the variation of life. Actually, there's even dispute about the classification into Kingdoms, with Domains being an alternative higher 'order' (hard to find the right word here because 'order' and 'class' are themselves terms in the classification). DirkvdM 09:24, 19 December 2005 (UTC)
Japanese fonts
Hi, this is a question related to Wikipedia. I recently re-installed windows and now I seem to have lost my japanese fonts. I can't edit japanese content anymore because everything shows up as question marks in Firefox and IE. Where do I download japanese fonts for windows so I can edit again? I've had no luck googling for the answer. Thanks --Quasipalm 05:30, 19 December 2005 (UTC)
- In Firefox, click View --> Character Encoding, and see if you can pick one of the goodies there that works... --HappyCamper 05:44, 19 December 2005 (UTC)
- Thanks, but I checked that early on and Firefox recognizes the page as Japanese or UTF-8 as the case may be, but it simply doesn't show correctly. This lead me to believe that the fonts on my system don't have glyphs for Japanese, but I'm clueless how to find fonts that do that I can install. Thanks for the follow up though, I should have added that to begin with. --Quasipalm 17:16, 19 December 2005 (UTC)
- On a related note, doesn't wikipedia have a page where you could test this stuff out and then gave instructions on how to get the fonts? I could swear I came across something like that while reading the Unicode article.--Ridge Racer 06:16, 19 December 2005 (UTC)
- It's the sandbox. Max 216.209.153.57 15:05, 19 December 2005 (UTC)
- If you go to the Microsoft website, you can download Japanese at [13]. That's what I did, but it doesn't work with all versions of Windows, and you might need Office XP. smurrayinchester(User), (Ho Ho Ho!) 18:58, 19 December 2005 (UTC)
- I think people are often a little too keen to download things which they already have. Windows 2000 and XP come with all the Japanese fonts and stuff you need, you just have to install them. This is an indirect process: basically you tell Windows you want to support a language (and this involves more than installing the font) and Windows will do what is required (have the Windows CD handy). Start at the Regional/International control panel. Notinasnaid 18:04, 22 December 2005 (UTC)
plane of voltage generation in piezoelectric crystals.
sir, Is the plane of application of stress and plane of voltage generation same in the case of piezoelecric crystals(both 2d and 3d)??.if no how do they vary? 07:48, 19 December 2005 (UTC)
Piezoelectricity does give me a clear answer. It seems to be normal to the stress vector, and the piezoelectric vector, I imagine this has to do with symmetry. Dominick (TALK) 18:10, 19 December 2005 (UTC)
Globalization
what will be the necessary steps about Globalization for the undeveloped country ?
<Email removed - please see instructions at the top of the page.>
- I'm afraid I don't understand your question linguistically, but you may find the following articles useful: Globalization, Anti-globalization, and Economic development. Happy reading! — QuantumEleven | (talk) 10:35, 19 December 2005 (UTC)
I'll hazard a take at this question. In order for an undeveloped country to become successful in the global economy several things must happen:
External factors
- Developed nations must be willing to trade with your country on a level playing field. This includes no tariffs, quotas, or other trade restrictions, and no subsidies for competing products from their end. Current WTO trade negotiations are moving in this direction, but we are not there yet.
Internal factors
- Transportation infrastructure; such as roads, railroads, seaports, and airports; must be developed.
- Communications infrastructure; such as telephone lines, cell phone towers, satellite phone access, and internet access; must be developed.
- Energy infrastructure; such as electricity, natural gas, and gasoline; must be made available.
- Other infrastructure; such as drinkable water, sewage and garbage disposal; is also needed.
- Educated workers are needed which are willing to work and reliable. Typically, in the early stages it is necessary to import large numbers of highly educated workers. Later, as more natives become well educated in production techniques, they can take over many of the technical jobs.
- Modern housing is needed, with heat, air conditioning, indoor plumbing, etc.
- Security is needed. That is, workers and executives must feel reasonably safe from war, ethnic conflicts, terrorism, and hostage taking attempts. Ideally, these things can be eliminated entirely. If that is not possible nationwide, creation of a "safe zone" with heavy security, may be the only immediate solution.
- Stable government is needed. In particular, a peaceful method of succession is needed for transitions in government. The threat of coups or other political instability will drive off investments.
- Honest government officials are needed. Those which require bribes to do their jobs scare off investment, not so much due to the money itself, but rather due to the unpredictability of not knowing what level of bribes are required by each official.
- Honest government leaders are needed. Those which steal all the nation's resources leave little for infrastructure development. Democracy is typically necessary, but not sufficient, to get honest leaders. Voters must also put a higher priority on honesty than other factors, such as whether a candidate is of the same religion, ethnicity, or tribe as the voter.
StuRat 05:01, 22 December 2005 (UTC)
Synthesis of a sine wave from square waves
You've got that right. From square waves, not the common and easy other way around. I don't have a particular reason to want this right now, but looking at the samples of a sine wave on a sound file I got... well, inspired.
Anyway, after thinking about it a little I found out that this sum, (the fundamental is positive, though), leads to a somewhat "good" approximation of it:
As you can see, the values tend to expand indefinitely on the zero crossings of the 3rd harmonic, and the overall shape is not smooth but it is stable. Now, my questions:
- Is this the best method to approximate the sine curve?
- What could I use here to at least stop the indefinite growth at the zero crossings?
- If this was a signal, what could be used to smooth it? (a filter of some sort, perhaps?)
- Incidentally, how those electronic oscillators generate sine waves?
Anyway, any help and light on the subject would be nice. Thanks! :D ☢ Ҡieff⌇↯ 08:49, 19 December 2005 (UTC)
- I'm no expert on the subject (or any subject for that matter), but as a square wave can be made by adding up the odd numbered harmonics of a tone, the opposite could be done by substracting them. Right? Maybe that's what Subtractive synthesis does. DirkvdM 09:47, 19 December 2005 (UTC)
- Not really. Check square wave. The result of the additive synthesis using sine waves is imperfect. All these are really approximations. Also, the above sine approach was done by continually subtracting square waves of the fundamental wave. ☢ Ҡieff⌇↯ 10:42, 19 December 2005 (UTC)
- No, this is not the best basis for approximating sine curves. the best basis is obviously the sine curves themselves, wherein every Fourier series has only 1 term. Any basis that is "close" to sines will do better than square waves. I'll wager you'd do quite well with sn x for small elliptic modulus.
- Well, I meant with square waves, really. If I could afford anything else for the experiment involved here this wouldn't be a challenge, would it? Also, elliptic functions are far mor complex than a square wave function. ☢ Ҡieff⌇↯ 11:42, 19 December 2005 (UTC)
- Oh, I see. Well in general, Fourier series are unique. So if you've found the right Fourier series for sine in terms of square waves (I haven't checked it), then not only is it the "best" approximation; it's the only approximation. As far as elliptic functions being complex... well I just thought you were looking for any mathematical functions that could approximate sine curves, and from a mathematical standpoint, the elliptic functions are far more simple than square waves, among periodic functions. But I guess I misunderstood the question.
- Exactly. By the way, Fourier series pretty much apply only for sine waves, no? ☢ Ҡieff⌇↯ 14:43, 19 December 2005 (UTC)
- How can you ask that, after having just done a Fourier series with square waves? No, you can do Fourier analysis in any orthonormal basis. -lethe talk 16:13, 21 December 2005 (UTC)
- I've just never seen the name Fourier being used to call anything else involving something that isn't sines. ☢ Ҡieff⌇↯ 21:41, 21 December 2005 (UTC)
- How can you ask that, after having just done a Fourier series with square waves? No, you can do Fourier analysis in any orthonormal basis. -lethe talk 16:13, 21 December 2005 (UTC)
- Exactly. By the way, Fourier series pretty much apply only for sine waves, no? ☢ Ҡieff⌇↯ 14:43, 19 December 2005 (UTC)
- The growth that you see at the zeros should probably not be unbounded; it should stop at some finite limit. This is known as the Gibbs phenomenon, and is well known when approximating jump discontinuities with smooth functions. I've never seen it mentioned when it comes to approximating smooth functions by discontinuous ones, but it doesn't surprise me at all that they exist, and I expect similar methods to fix them would work.
- Good point. It never occured to me that these could be Gibbs or Gibbs-like. I'll look into it later. ☢ Ҡieff⌇↯ 11:42, 19 December 2005 (UTC)
- Just checked. They're unbounded! :| ☢ Ҡieff⌇↯ 14:05, 19 December 2005 (UTC)
- That's weird, I think it should be bounded. I wonder if the lack of differentiability is the cause of this. -lethe talk 16:13, 21 December 2005 (UTC)
- Actually, if you look at the signal function, they shouldn't be, since , and you're always dividing this value to the odd number of harmonic and adding that to the point near the node. I can't really explain this mathematically because I don't know the english terms, but the points near zero will always have something added/subtracted. ☢ Ҡieff⌇↯ 21:41, 21 December 2005 (UTC)
- A low pass filter ought to do the trick, no?
- Aaah! Thought it'd be able to chop those jumps. I'll have to experiment with it later. ☢ Ҡieff⌇↯ 14:05, 19 December 2005 (UTC)
- Yep. Tried the lowpass filter with only 10 harmonics and I got an excellent approximation. :D Still, I wonder if there is a filterless method. ☢ Ҡieff⌇↯ 02:12, 20 December 2005 (UTC)
- Aaah! Thought it'd be able to chop those jumps. I'll have to experiment with it later. ☢ Ҡieff⌇↯ 14:05, 19 December 2005 (UTC)
- AC (= sine curve) currents arise naturally ought of electric generators. I'm not sure how to turn a square wave into an AC wave. You could maybe get some nice approximations by combining some filters. Maybe an electrical engineer will happen by.
- Yes, AC = sine, but what about generating a sine curve from DC? I suppose you could play with some capacitors and diodes approximating a triangle wave signal, but that wouldn't be all that accurate either. ☢ Ҡieff⌇↯ 11:42, 19 December 2005 (UTC)
- The more I think about it, the more I think you probably cannot do this with simple analog circuitry. All circuit elements I know turn DC currents into at worst exponential decays. The only way to introduce sinusoids is with other sinusoids. So I'm thinking hook the square wave into an on/off switch for a generator.
- thinking even more: using resonance, you can get filters that select a narrow frequency band. Pass a square wave through that filter with the right band, and it should select only a single harmonic, which will be sinusoidal (to a great approximation).
-lethe talk 11:16, 19 December 2005 (UTC)
- Anyway, thanks for the answers so far! I'm still gonna take a good look at this... ☢ Ҡieff⌇↯ 11:42, 19 December 2005 (UTC)
- DC is turned into AC because you know exactly what youre trying to make (60hz pure sine) and the circuit is designed to pulse at a high frequency to 'build' the sine wave as it goes up and down, the current is then filtered via a coil into a near-perfect wave which then actually feeds back and modulates the PWM input to ensure the sine tracks properly at a varying load. This is 'easy' since there is a sine already present. Transistor audio amplifiers work the same way, except they use a variable input as the tracking source. Working from an unknown square wave is tough since you can't see the future to know when the pulse will end.
- Easier way to do this without anything fancy. Integrate the square wave, using a wide band integrator with a low frequency dump, you will get a good triangle wave. The triangle has much lower harmonic content, every other odd harmonic with flipped phases every other odd harmonic. Synthesize a sine from that. Another approach would be to filter the tringle wave, with a low pass filter. You would be able to use a simpler LPF.Dominick (TALK) 16:17, 19 December 2005 (UTC)
- Why not just use a low pass filter? That should do the trick. --HappyCamper 00:14, 20 December 2005 (UTC)
- I don't know what it is, but that infinite series does not look quite right...unless....hm....... --HappyCamper 00:06, 21 December 2005 (UTC)
Contamination / Oxidize "Aluminium"
Hello my name is Keith, I'm a steel worker I have just started working with aluminium and myths are floating in the air and i'm looking for some help, I was just wondering if you were to grind on mild steel and the red hot sparks are shooting off and hitting "In Contact" the Aluminium what would happen? would it be contaminated, corroded, oxidized??? please help.
- Hi Keith. I'm not an expert on this, but as I understand it the red hot sparks from a grinding wheel are pretty small and cool down very quickly (something I've confirmed by being hit by them as they come flying off my Dad's angle grinder). I would think that they'd generally just hit the aluminium and bounce off. I'd be more worried about the abrasive effect of the bits of steel flung at the aluminium damaging that lovely shiny aluminium finish more than anything.
- If a piece of steel did somehow manage to embed itself in the aluminium, the steel would almost certainly corrode first.
- However, all of the above is speculation, I'm really not an expert in this. You might want to look into some books on the subject; [http://www.amazon.com/gp/product/1574091131/103-0256836-4039832?v=glance&n=283155 this book at Amazon.com" looks interesting. Or hopefully a real expert will be able to comment here!--Robert Merkel 11:15, 20 December 2005 (UTC)
- I remember some warning about getting the grinder too hot, after working on aluminium and iron - it's possible to start a thermite reaction? Tzarius 04:08, 22 December 2005 (UTC)
- Nope. Not in this situation...remember, those sparks are caused by friction, and are just hot shavings of metal. They are rather small, and by the time they hit the aluminum, I would expect them to be relatively cool, and not do much damage to the aluminum. It would not initiate any significant chemical reaction. Well, I suppose you can stretch this a bit, and say that the shavings might scratch the surface, which causes it to oxidise, but this is a good thing - when aluminium oxidises, the coating is actually a protective one - it is not like iron where the oxide (rust) falls off and causes structural damage. --HappyCamper 04:12, 22 December 2005 (UTC)
- Except that most people find the white aluminum oxide ugly as compared with shiny polished aluminum, especially when it appears as spots, making the aluminum look like it has a disease. StuRat 23:54, 22 December 2005 (UTC)
- Would it be possible for the Wikipedian who asked this question to take pictures? That would be great for articles here! --HappyCamper 00:57, 23 December 2005 (UTC)
Accelerometers
How does an accelerometer work, where can I get one, and how much would it cost? Please help, Max. 216.209.153.57 15:16, 19 December 2005 (UTC)
- With a quick Froogle search, electronic accelerometers go for about $100-200. Did you check out the article to see how they work? — Asbestos | Talk (RFC) 16:18, 19 December 2005 (UTC)
The article doesn't say how they work; it's almost a stub. Max 216.209.153.72 23:00, 19 December 2005 (UTC)
I could beef that article up (whoops I was thinking of accelerograph), but it's more oriented towards seismic accelerometers. (There are many types that all work differently.) In general it is difficult to get a good accelerometer up and working. There are some lab demo kits for the 'cheap & cheerful'. Most accelerometers just output a voltage; then you need a data acquisition card and software to analyze the results. For seismic work, I always wanted a small laptop kit for measuring equipment resonance, but everything is very expensive. --Zeizmic 14:59, 21 December 2005 (UTC)
Climbing stairs
I climb eight flights of stairs several times a day to my office. Which would give me the most benefits of exercise, taking them singely or two-at-a-time? (Using any definition of "benefits of exercise" you think fit).
— Asbestos | Talk (RFC) 16:16, 19 December 2005 (UTC)
Well, I don't if anyone could really give a factual answer to this, but I think it goes like this. When you take two stairs at a time it equates to taking a larger stride, but one stair at a time would turn out to a longer distance. So, I would say taking one stair gives you more than or equal to the amount of exercise that you would get from taking two stairs at a time.--Ridge Racer 18:30, 19 December 2005 (UTC)
- This is practically equivalent to "should I life small weights for many reps or large weights for a few reps?" The answer depends on your goal. Do you want to build endurance or strength? Longer strides will build strength and more short strides will build endurance. As for the excercise of stair-stepping, I am influenced by the hypertension studies all around me in the hospital where I work. If your heartrate is not elevated for 20 minutes, it is not effective cardiovascular excercise. Then, a joke made by a doctor at a conference I attended where a similar question was asked: "Why not bunny hop each step? That will be a workout you won't forget." Just to note, I work on the 12th floor and the doctors try to force us to use the stairs. I usually cheat and ride the elevator up to the 11th floor and then walk up the last one. --Kainaw (talk) 23:52, 19 December 2005 (UTC)
- Doesn't it look suspicious when you arrive fit? Normal people would be panting after climbing 12 floors. Anyway, it's indeed the amount of effort you put into it. I once walked a marathon. I even carried a daypack and it was up and downhill over fairly uneven tracks. This took me over 10 hours. But I'm confident I couldn't run a marathon. So faster means more exercise. DirkvdM 08:57, 20 December 2005 (UTC)
Infared LED
I'm searching for this article, please give me some infos about that. Thanks
infrared and Light-emitting diode Dominick (TALK) 18:03, 19 December 2005 (UTC)
More specifically for infared light emitted by LEDs try Infrared#Communications.--Ridge Racer 18:07, 19 December 2005 (UTC)
Upgrading Windows ME to Windows XP...
Is it at all possible to upgrade from Windows ME to Windows XP Service Pack 2?--Archducky Duck
Yes, but you would need to back up your stuff, then reformat your hard drive and reinstall with XP SP2.--Ridge Racer 18:24, 19 December 2005 (UTC)
Are you positive? Because I'm on the verge of buying the XP SP2 CD on eBay, and I wouldn't want to waste my money...--Archducky Duck
- If you have the software and the licence, there shouldn't be a problem. Mind though that the system requirements for windows XP may give you some problems. See [14]. -- Ec5618 19:02, 19 December 2005 (UTC)
It is not necessary to reformat the hard drive in order to upgrade Windows ME to Windows XP. In the process of updating, setup determines whether the file system should be changed from FAT32 to NTFS, based on some criteria I am unaware of-- perhaps compatibility with programs already installed. (After the upgrade, it is possible to change the file system once from FAT32 to NTFS; this has some benefit as regards resistance to file corruption, and will permit native file encryption if you're upgrading to Windows XP Pro rather than XP Home). Some old programs that directly access the hard disk may not work if you change to NTFS. Also, as Ec5618 mentioned, there are many hardware issues, and much legacy hardware that would otherwise be compatible with XP does not have approved XP drivers available. There is an XP upgrade advisor wizard that runs automatically during XP setup which can point out these issues before you make the upgrade. Alternatively, you can run the wizard as a standalone program. see: Windows XP Upgrade Advisor--
Mark Bornfeld DDS
Brooklyn, NY 21:11, 19 December 2005 (UTC)
Disruption of Lunar Orbit
What would happen on earth if an asteroid or meteor strike knocked the moon out of its normal orbit?
- There would be a huge distruption of the tides, possibly causing tsunamis and other such events. If the knock was big enough, it might distrupt the Earth's orbit. I guess the moon could also crash into the Earth if the blow knowcked it inwards or slowed it down. — Asbestos | Talk (RFC)
- What would happen if the Moon did impact the Earth? Would gravity immediately crush the Earth+Moon combination into a sphere, or would it stay funny-shaped for some time? I'm guessing there would be a pretty major impact winter regardless... —Keenan Pepper 21:06, 19 December 2005 (UTC)
- The moon would break up first when it reached its Roche limit, forming something roughly like Saturn's rings. - MPF 23:59, 19 December 2005 (UTC)
- No, that would depend on the structural integrity of the moon. The Roche limit refers to bodies held together only by gravity. The moon's material strength and resistence to tensile stress would keep it intact inside it's Roche limit. I don't know how strong the moon is, but I would assume it could make it all the way to impact before it broke apart. - Taxman Talk 16:27, 20 December 2005 (UTC)
- I was thinking that too. The roche limit isn't all that far from the Earth's surface anyway (about 1.5 times the radius). So, how long would it take Earth+Moon to be crushed into a sphere? Would the pressure make the rock flow as a liquid? —Keenan Pepper 19:32, 20 December 2005 (UTC)
- Yes, the Earth/Moon combo would become molten, with all the oceans vaporized, and would quickly settle back into a slightly larger sphere and then cool in that shape, with a thin solid crust containing new continents and oceans. The collision might also send out several large clumps of materials that would form a series of smaller moons. StuRat 03:50, 22 December 2005 (UTC)
In the original question, "knocked the Moon out of its normal orbit" is rather nonspecific. If the Moon was deflected by a small amount, that'd be "out of its normal orbit", but there wouldn't be any major effects on the Earth. The biggest effect would probably be cultural: the length of the lunar month would change, and all cultures using a lunar calendar (such as Islam) would need to deal with that. Also, solar eclipse fans, who might already have trips planned to see eclipses over the next few years, could find their schedules all wrong.
If the Moon was deflected into a more eccentric orbit without much change to its period (the lunar month), that would mean that it would be closer when at perigee and farther when at apogee. Even a small change might noticeably affect the tides, since tidal force varies as the inverse cube of the distance. Sometimes when a coastal region is threatened by flooding, a higher-than-usual tide can cause the flood to happen; the perigee change might make that a more common occurrence. Apogee and perigee changes could also give some solar eclipses a noticeably different appearance than now.
But I suspect the intention was to imagine a more violent disruption, one that deflects the Moon into a grossly different orbit. In that case we wouldn't be worrying about tides -- the energy relase from the impact itself would be, well, astronomical. The Moon's kinetic energy, if I calculate correctly, is about 4 x 10^28 joules. If just 10% of that energy went into heat, that would be equivalent to a trillion-megaton explosion. And don't forget that the impacting body will contribute kinetic energy of its own that will also turn into heat. I don't know how to calculate it, but I would guess an impact that size would be enough to cause significant radiant heating on the Earth. Not to mention fragments splashing out, large enough that some of them could cause damaging meteorite impacts on the Earth, maybe even global-disaster-level effects.
--Anonymous, 07:40 UTC, December 20, 2005
- There is a 50% chance the collision would be on the far side of the moon, in which case the radiation wouldn't be a problem for us. (The chance might be less than 50%, if the Earth provides some shielding of the near side.) Large meteors resulting from the collision might still hit the Earth, though, even if the impact was on the far side. StuRat 04:04, 22 December 2005 (UTC)
- That clearly leaves us with only one option... Eliminate the moon before it eliminates us!!! But seriously, are there even any known asteroids with near enough mass to disturb the moon that greatly, if they were to hit it?
- I was curious about this, so I fed the problem to the Impact Effects Calculator. Assuming the Moon were to simply halt in its orbit, dropping straight down onto Earth and colliding after 2.5 hours, the energy of its impact would be 2.92x1032 J, just exceeding the combined gravitational binding energy of both objects (2.285×1032 J). This seems to be reflected in the calculator's estimate that the crater diameter would be 11,300 km. At least someone on the far side of Earth should have twenty minutes of relative safety. ‣ᓛᖁ♀ᑐ 16:58, 22 December 2005 (UTC)
- And that calculator probably assumes that the crust would not be ruptured. When it does, the effect would be even more dramatic. StuRat 23:46, 22 December 2005 (UTC)
Antimony
I wante to know if Antimony bioaccumulates like Lead or Mercury.
- Antimony is more like arsenic when it comes to poisoning. --Kainaw (talk) 20:13, 19 December 2005 (UTC)
- Antimony died by falling on his sword, but Cleopatra died from snake poison.
- ...I couldn't resist. --Sum0 20:39, 19 December 2005 (UTC)
- And here I thought antimony was another name for reverse-alimony. LOL. StuRat 03:42, 22 December 2005 (UTC)
Physics lecture
Many years ago when I was taking lower division physics my professor remarked that every equation used in physics can be derived from one of eight fundamental equations, one of which was F=ma (the only one I remember). What might the others be?
- F=ma doesn't really work in modern physics. Max 216.209.153.72 23:02, 19 December 2005 (UTC)
- But F=ma would be pretty helpful for lots of stuff, and there are seven more. That being said, I couldn't begin to guess which eight he might've meant. Some important ones are:
- Maxwell's equations (normally four, but can be written as one)
- The lagrangian for the Standard Model of particle physics
- Lagrange's equation of motion.
- Oh, heck. I really have no idea, and it'd take pages to explain what's up there already. ;-) -- SCZenz 23:11, 19 December 2005 (UTC)
- I think the non-logged in user above means that F=ma is wrong, while, say, F=dp/dt is equivalent classically, but is also correct in modern physics sense. --Ornil 04:28, 20 December 2005 (UTC)
- But F=ma would be pretty helpful for lots of stuff, and there are seven more. That being said, I couldn't begin to guess which eight he might've meant. Some important ones are:
- E=hf is quite important. --Bob Mellish 23:14, 19 December 2005 (UTC)
Why not just go with 2: Einstein field equations, and the Standard model equation of motion? -lethe talk 23:25, 19 December 2005 (UTC)
I remember hearing something similar. Also, Hawking wants to describe everything with one superformula. So how may are there now? Or what if we limit it to 'traditional physics'? The SI base units are mass (m, kg), time (t, s), length (l, m), electrical current (I, A), temperature (T, K), quantity of matter (n, mol) and luminous intensity (I, cd). How do they relate? The SI derived units give relations. Which of these are basic? Of course Hertz doesn't count because it is only expressed in one unit (the second). Then there's
- Force: F = ma
- Energy: E = mv²
Power doesn't qualify either because it's expressed in terms of energy and time, which we already have. Same for many others. But then there's
- Electric charge: V = It
Confusingly, 'I' can mean two things. Are there no unambiguous symbols? (I looked these up in a science table book. Shouldn't those be given in those articles?). Anyway, on I go:
- Magnetic flux: how do you write that?
Oh dear, this is too long ago. I think the principle of what I mean is clear. But someone more knowledgeable could do this much more easily. DirkvdM 09:56, 20 December 2005 (UTC)
- The best answer is probably that what your professor told you is inaccurate, if not downright wrong. If you're looking for important formulas in classical physics, then you should definately mention Maxwell's equations and the laws of thermodynamics. It would make more sense to say that all measurable quantities can be measured in units derived from 7 fundamental units, as indicated above. Hope this helps. Siebren 12:57, 20 December 2005 (UTC)
<MATH>
- why is does it make <math></math> into , when theres nothing inbetween the tags'?— Preceding unsigned comment added by 152.163.101.12 (talk • contribs)
- Interesting "bug"! iso - 8859 - 1 is the standard character encoding on TeX, I'd suppose. Who'd have thought it'd show up like that! ☢ Ҡieff⌇↯ 00:41, 20 December 2005 (UTC)
December 20
Hydrocarbons
Where can i find properties of hydrocarbons, and how they affect characterization and use for gasoline? Ive been looking for hours
- Did you try the article on gasoline? Do you have a specific question? —Keenan Pepper 01:08, 20 December 2005 (UTC)
--Thank you, i think this is exactly what im looking for :D, i could have sworn i checked here before though, been to so many sites..... thanks again
- Depending on which properties you're looking for the Handbook of Chemistry and Physics may also be of use to you. - Mgm|(talk) 12:28, 20 December 2005 (UTC)
The chemical sentence for glucose
- I don't understand what "chemical sentence" means, but the formula for glucose is C6H12O6. —Keenan Pepper 01:04, 20 December 2005 (UTC)
- The glucose page gives it as 6-(hydroxymethyl)oxane-2,3,4,5-tetrol - MPF 14:01, 20 December 2005 (UTC)
3 bluescreens in 3 days
...is three too many. Dell Inspiron 5100, 384MB, XP. It seems to happen after I go away for a few hours, leaving the laptop on, with the lid closed. The blue screen has no useful information, only hex addresses. Windows keeps a data log which I've forwarded to the Microsoft web site; but the automated analysis there simply says the problem was caused by an (unknown) driver. I haven't installed any drivers for a very long time. I did perform two system restores, the first to the day previous and the second to two weeks earlier. A non-Dell tech suggested it might be a memory problem, citing a previous case with the same computer. He said I had 256K and 128K memory chips and that if one of them wasn't working it could cause a pointer error, corrupting memory and causing the crash. Is this reasonable? What should I do? Thanks, Halcatalyst 01:52, 20 December 2005 (UTC)
- Well, to test if the memory is bad, use Memtest86. It takes awhile to run but is pretty good in seeing if that's the source of the problem. If is, you figure out which RAM card is bad and replace it, not very hard. If it isn't RAM, then you have to try other things. --Fastfission 03:05, 20 December 2005 (UTC)
- It lost me when it asked me to enter the disk image source file name. I'm afraid I don't have nearly enough technical expertise to use the tool. Thanks anyway, Fastfission. Halcatalyst 03:24, 20 December 2005 (UTC)
- I had almost the same thing with an older Gateway. Turned out the heatsink on the CPU had become loose. Put on some lithium grease (better to use thermal if you have any) and tightened (but laptops are tricky beasts to take apart and put together). Now it can run forever, compiling Linux kernels. --Zeizmic 23:14, 20 December 2005 (UTC)
- Your computer has determined that you are damaging your health by spending too much time online viewing porn (if that's actually possible), and decided to shut down to protect you. StuRat 07:40, 22 December 2005 (UTC)
Why do we see our breath on a cold day but not on a warm day?
Our cells produce water when they undergo cellular respiration to produce energy. Glucose, processed from our food, is broken down into pyruvate in the cytoplasm, protons (positive hydrogen ions) and electrons extracted from it, which is then oxidised with oxygen to yield water. This produces water in our breath when we exhale. Heat, due to entropy in cellular respiration, makes this water particularly warm. This allows more water to be dissolved into the air. On a warm day, our breath isn't much hotter than the surroundings, and it loses very little heat, thus keeping most of the water dissolved (transparent/hidden). On a cold day, the saturation capacity of our breath decreases immensely as it loses heat to the cold air, making the water in our breath condense. Thus the water particles originally produced in our mitochrondria become visible. -- Natalinasmpf 02:24, 20 December 2005 (UTC)
- An incredibly complex answer is given above, but the basic point is indeed that the water vapour is usually free to remain an invisible gas, but on cold days it condenses to tine (visible) droplets of water. Notice how the steam from a kettle is invisible until it's a few centimetres away from the nozzle — the water cools and condenses. -- Ec5618 12:02, 20 December 2005 (UTC)
- I'd also note that the incredibly complex answer above is trying to be too clever for its own good. Most of the water we exhale isn't the product of cellular respiration; it's the same stuff we consumed as part of the food and beverages in our diet. It makes its way through the body–as a component of blood plasma, lymph, or miscellaneous interstitial fluid–and some eventually ends up coating the surface of the lungs. (From there, it readily evaporates as described.) TenOfAllTrades(talk) 16:49, 21 December 2005 (UTC)
- The sources of heat and moisture in one's breath are completely irrelevant to the question and should be a "given" unless the questioner asks for more detail. StuRat 03:06, 22 December 2005 (UTC)
- But I was bored. Alas. -- Natalinasmpf 03:42, 22 December 2005 (UTC)
- Ok, we can forgive you then. I am looking forward to your recipe for lemonaide that starts with the mitosis cycle for cellular reproduction in the lemon tree. Don't forget to list the number of chromosmes ! LOL. StuRat 07:33, 22 December 2005 (UTC)
In which layer of the atmosphere is the aurora borealis displayed? What is the cause of this natural light show?
Please do your own homework.- Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. Anyhow, see aurora borealis. -- Natalinasmpf 02:52, 20 December 2005 (UTC)
More circuitry questions
I know I know, I ought to just figure this stuff out already, right? Well, until I do, here goes:
On the CD40106 DIP I mentioned above, the schematic calls to connect components to pins 1-6, in 2 pin pairs. Is it kosher to connect the parts that were supposed to go to pins 3 and 4 instead to pins, say, 10 and 11? It would make layout of my board much easier, because as it stands, all my parts are on one half of the board.
Oh, and if any of you have any good reference to websites or books that have instruction on basic circuitry, I think we all would appreciate that :). I find a lot of stuff on basic electronics, but it's largely theorhetical and doesn't really help me once I start to build. Thanks! --ParkerHiggins | Talk 04:03, 20 December 2005 (UTC)
- Yes, since that IC has six identical copies of the same gate, you can swap any gates over as long as you follow the correct pinout, e.g. instead of pins 3 & 4, use pins 11 & 10. Note you have to make sure you get the input and output in the right order.
- Absolutely the best electronics book for beginners, IMO, is this one: [15]. Seems not to be in print anymore (you used to be able to buy it from Tandy/Radio Shack), but it covers everything you need to know with a strong emphasis on practical rather than theoretical. --Bob Mellish 04:32, 20 December 2005 (UTC)
Ice
If I add some ice (0 degree celcius) to hot water of 40 degree celcius, after 5 minutes, lets say that the hot water became 38 degree celcius, what would the temperature of the ice be? Would it remain 0 degree celcius or the temperature of the ice increases? --165.21.83.240 07:20, 20 December 2005 (UTC)Naruto90
- When ice gets above 0 celsius, it is no longer ice. There is a period of latent heat, where added energy does not increase the heat, but after that, the ice melts. --ParkerHiggins ( talk contribs ) 07:23, 20 December 2005 (UTC)
- (My answer was longer, and had formatting issues, but, pretty much the same thing):
- The ice would melt, and become water, 40oC is certianly hot enough to change it all the way to liquid phase, thermodynamically though, you're right, ice melting in hot water could be broken down into
- Water(solid,0oC)-->Water(liquid,0oC)
- &
- Water(liquid,0oC)-->Water(liquid,near40oC
- seperating out the phase change, and the temperature change, while remaining energetically equivalent to the origional reaction,
- Water(solid,0oC)-->Water(liquid,near40oC)
- so yes, basically, it would melt--Aolanonawanabe 07:28, 20 December 2005 (UTC)
- Depends. No quantities are given. Suppose you threw an iceberg 'into' a puddle of warm water? :) But couldn't the relative quantities be calculated based on the water temp dropping from 40 C to 38 C in 5 mins? Anyway, the answer stays the same. The ice (if any, but the question implies there is some, unless it's a trick question) will be at 0 C. DirkvdM 10:06, 20 December 2005 (UTC)
- To answer the literal question, if any ice remains, it would be at 0 °C. At equilibrium, the whole system will be at the same temperature. As explained above, what happens depends on the relative amounts of ice and warm water. If there is only a small amount of water, it be sufficient to melt only part of the ice before it was cooled to 0 °C; you would end up with an ice-water mixture at 0 °C. If there is sufficient water, the ice will all melt and the result will be all water at some temperature between 0 °C and just below 40 °C (of course, depending on the relative amounts). — Knowledge Seeker দ 02:12, 21 December 2005 (UTC)
Fast
Can anything or is there anything that is able to move faster than the speed of light??? If no, why can't anything move faster than light???
165.21.83.240 07:19, 20 December 2005 (UTC)Naruto90
- Things can appear to move faster than the speed of light in vacuum (c), but no matter or information can actually travel faster than c. According to special relativity, anything that appears to be moving faster than light to some observers will appear to be going backwards in time to other observers. In other words, faster-than-light travel is equivalent to time travel. —Keenan Pepper 07:37, 20 December 2005 (UTC)
- Nothing can move faster than the speed of light in a vacuum. But things can move faster than the slower speed of light in non-vacuum situations. When a fast-moving atomic particle exceeds the speed of light in air or in water, it produces a shock wave (a bit like a sonic boom). For more details, see Cherenkov radiation. - MPF 11:31, 20 December 2005 (UTC)
- Speed is a relative concept. I could be moving at 0.5 lightspeed (as measured from Earth), drop a buoy, and fire my boosters to accelerate to another 0.5 lightspeed (as measured from the frame of reference of the buoy). Oddly, to observers on Earth I will not be moving at the speed of light, and since time moves differently for me, They will see me moving at about 0.7 lightspeed. I could drop another buoy and accelerate again (instinctively one would say I was moving at 1.5 lighspeed, but to observers on Earth I will be moving at about 0.8 lightspeed). In my frame of reference, things would be different.
- Consider that speed is distance times time, and that time is a relative concept.
- Light, in my understanding, is a somewhat timeless concept. It moves at the maximum speed in our frame of reference, but from the point of view of the photons themselves they reaches their destination at the moment they are created. -- Ec5618 11:58, 20 December 2005 (UTC)
- You may also want to read the answer to the question Is Faster Than Light Travel or Communication Possible? in Usenet Physics FAQ if you want to learn more about the details. – B jonas 12:45, 20 December 2005 (UTC)
- See tachyon for a description of a theoretical superluminal velocity particle. StuRat 02:57, 22 December 2005 (UTC)
Two-way radio
Is there any two-way radio in the market that has encryption feature? roscoe_x 08:40, 20 December 2005 (UTC)
how do you make a radio
i want to make a simple radio reciver and transmitter for my science fair .can anyone help my in my quest?
- See crystal radio, particularly the external links. Proto t c 10:40, 20 December 2005 (UTC)
Prefixes
Why do we have prefixes like kilo- and mega- when they mean exactly the same as 'thousand' and 'million'? The overview at SI prefix shows there is such an equivalent for each prefix. So what is the use of using different names than the ones already generally known? Well, one reason might be the ambiguity of a word like 'billion', according to culture. But is that the only reason? DirkvdM 10:22, 20 December 2005 (UTC)
- Of course centi for hundreth. my guess is that the prefis are easier to work with and have unique 1 letter codes that are unambiguous. Thousand, ten, thousandth all start with a T. i emphasise this is a guess. David D. (Talk) 10:31, 20 December 2005 (UTC)
Well, believe it or not, there was a time when English wasn't "already generally known" and ancient Greek, like Latin, provided an acceptably neutral core for a non-nationalist scientific language in the 18th and 19th centuries. The prefixes are part of the metric system, which dates to the early 19th century and has lots of advantages. alteripse 10:35, 20 December 2005 (UTC)
Another minor advantage of the prefixes is that they are shorter when written out. Per alterprise, cultural neutrality probably played a big role. Note that the metric system was a French development; if we were to use the vernacular we would have millemetres, centmetres, and dixmetres—not thousandmeters, hundredmeters, and tenmeters.
Meanwhile, you can see the potential for trouble if each region were to use its own language in the units. The British wouldn't have been willing to adopt a system that used French prefixes, so going back and forth from the Continent would have required replacing all those thousandmeters (tm?) with millemetres (mm?). Using the Greek-derived prefixes cuts down on the confusion; everyone can unambiguously use kilometers (km). TenOfAllTrades(talk) 12:24, 20 December 2005 (UTC)
- To see an illustration of potential difficulties, look at the early history of railroading where different nations had different widths between the tracks, meaning a lack of global standards, so trains were designed to run in a particular nation. I have heard it tell that this was done deliberately because some leaders were sufficiently farsighted and paranoid to realize that an army traveling by train could get into their nation pretty fast and economically if their trains required same width between wheels as everyone else. I never learned whether that was ancient history urban legend or not. User:AlMac|(talk) 21:46, 20 December 2005 (UTC)
- That problem certainly occurred in Australia when it was a bunch of separate British colonies and not a unified nation (1901). Most of the colonies had unique rail gauges. Travellers between Sydney and Melbourne, the capitals of New South Wales and Victoria, had to change trains at Albury. The problem was not finally fixed till the 1960s, believe it or not. That's why Albury had one of the world's longest railway platforms. JackofOz 22:42, 20 December 2005 (UTC)
- From Track gauge, In the nineteenth century, Russia chose a broader gauge. It is widely believed that the choice was made for military reasons, to prevent potential invaders from using the Russian rail system. Shimgray | talk | 20:02, 21 December 2005 (UTC)
chemistry
Are diamonds compounds?
- No, diamonds are pure carbon. They may contain impurities, but the diamond itself is comprised of one element. Proto t c 12:08, 20 December 2005 (UTC)
- You might be confusing diamonds with Cubic Zirconium, which is a compound resembling diamond.
Airplane doors
Is it true that on passenger airplanes it is impossible to open the door mid-flight due to the differential in air pressure between the inside and outside of an airplane cabin? Regards, Gallaghp
- There's probably safety locks on those doors preventing them from opening but I think it's relatively easy to do so if that wasn't the case. Airplane cabins are pressurized to approximately the same pressure as people feel on the ground, which would be higher than the low pressure of the air outside. High pressure inside versus low outside, would make opening a door relatively easy. It's the exact opposite of trying to open a door underwater at the bottom of the sea. The pressure there is a lot higher than on ground level because there's a lot more air (and water) above you applying pressure. So underwater, the pressure outside is high enough to keep you from opening the door. - Mgm|(talk) 12:35, 20 December 2005 (UTC)
- Mgm, that would depend on your definition of the phrase "same pressure as people feel on the ground". Commercial jets are not pressurized to pressures one might feel at, for instance, sea level. The pressure within the airplane would be equal to that of a few thousand feet above sea level. See Cabin pressurization for more info. Dismas|(talk) 13:35, 20 December 2005 (UTC)
- Boeing's answer on the matter is that the door cannot be opened during pressurised flight. Their website (at least that part) doesn't explain why, but my guess is that the door has a plug design. When the lever is pulled, a plug action is observed where the cabin pressure makes it impossible to push the lever back. You will notice that I have completely avoided disucssing the design of this system, becuase I have no idea how it works.--Commander Keane 14:10, 20 December 2005 (UTC)
- Mgm, I'm pretty sure that the doors on (most, if not all) commercial airliners open inward; consequently you would need to pull the door open against the air pressure difference. (They're plug-type doors; they are larger than the opening in the cabin that they seal.) At altitude, the pressure difference between the cabin and the surrounding air is about 8 psi (55 kPa), which works out to aboute ten tons of force on a typical cabin door. TenOfAllTrades(talk) 14:34, 20 December 2005 (UTC)
- Mgm, that would depend on your definition of the phrase "same pressure as people feel on the ground". Commercial jets are not pressurized to pressures one might feel at, for instance, sea level. The pressure within the airplane would be equal to that of a few thousand feet above sea level. See Cabin pressurization for more info. Dismas|(talk) 13:35, 20 December 2005 (UTC)
Dismas is correct, but the pressure difference between the inside and outside of the plane is still substantial, up to about 1/2 atmosphere, which means that the force on a normal-size door is something like 20,000 pounds (10,000 kilograms-force or 100,000 newtons).
What Mgm is missing is that airliner passenger doors are normally designed to open inward, and so the answer to the question is yes. This design means the latch only has to be strong enough to keep them from coming open due to wind, vibration, and so on when the aircraft is near the ground; it doesn't have to resist the huge force created by the pressure difference. I think I've heard of a model of airliner that does have outward-opening doors, but it would certainly be the exception.
In some cases cargo doors don't have space to open inward, in which case they do require latches that strong. Consequently, the failure of a cargo door can be disastrous. But with the mechanism normally locked, it would still be impossible to open it deliberately in flight because the pressure would keep the bolts from sliding.
--Anonymous, 14:30 UTC, December 20, 2005
You should watch a program about how a boeing door locks failed and the parents of a New Zealander who died in the crash, who pushed and pushed and pushed and pushed and came up with the truth. He was an aeronautical engineer or something similar. I might I add that it wasn't easily accepted by the air transport authorities, the door locks were made from very, very lightweight aluminium that was known to be and previously ordered to be changed, by boeing, so that it wouldn't fail.
Very interesting
- Not all airplane doors open inwards, however, the ones that open outwards have a double action mechanism whereby they cant inwards before swinging out (the MD-80 is an example). Also, Anonymous is correct about cargo doors. The A320 series is an example of cargo doors that swing outwards, but their cargo doors are so heavy that they're only articulated by a motor, not by hand. I'm not sure if the emergency exit doors on commercial airliners can be opened in flight, I doubt they'd want any mechanism that would impede their opening at all. IIRC, some 60's-era aircraft even had explosive bolts for the emergency exits. -User:Lommer | talk 02:03, 22 December 2005 (UTC)
- I would guess that those airplanes with cargo doors that open outward do not have pressurized cargo compartments. Otherwise, the huge forces acting on the cargo doors would be difficult to control with any latch mechanism. StuRat 02:37, 22 December 2005 (UTC)
- Pressurizing the cargo compartment allows the pressure hull to be more or less a cylinder, which is a strong shape. If the cabin floor was part of the pressure hull, it would need reinforcement all along the edges where it meets the walls. Also, an unopressurized cargo compartment could not be accessed in flight even if some emergency made it desirable. These issues are more important than the cost of a strong latch on the door. --Anonymous, 10:50 UTC, December 22
- A "strong latch" does not begin to describe it. If there was only a 1 psi difference in pressure from the interior to the exterior of a large, 120x150 in cargo door (say on a C-130), the force on the door during flight would be 9 tons ! StuRat 23:38, 22 December 2005 (UTC)
particle technology
what is meant by sub sieving and what is its importance? --61.17.183.141 12:36, 20 December 2005 (UTC)--
sexual disorder
Can anybody help me, I suffer from hasty disscharge of sperm
- Yes, someone more than likely can help you. I'm guessing it's nobody here though. Dismas|(talk) 13:40, 20 December 2005 (UTC)
- That was not helpful. See premature ejaculation. Proto t c 15:03, 20 December 2005 (UTC)
- You didn't say under what conditions this occurs, but my guess is that should practice the "stop and go method" of masturbation to teach your body to hold out and not ejaculate too soon. - Mgm|(talk) 20:47, 20 December 2005 (UTC)
The Diesel Engine
I recently heard a lecture about Herbert ?-Stewart or Stuart, I forget his mothers name, however I can easily get it again though it's too late tonight.
I was stunned, bemused, absolutely enthralled.
It seems that he patented the fuel oil compression engine specifics in 18??, in England, this being on the record.
Why then is Rudolf Diesel credited with the "INVENTION" when he patented his specifics two years later?
I will put the entire lecture that I heard on this page
I understand that there have been many Herbert ?-Stewart or Stuart lectures over the subsequent years however it seems that the community has seen fit to believe the promotion put forward by Rudolf Diesel that he alone was responsible for the invention of the 'fuel oil compression engine'.
It is common for multiple persons to be developing technology at the same time however it has been the accepted practice that the first patent is credited with the invention of the device.
It is a matter of record that Herbert ?-Stewart or Stuart, did build a working engine however it is not known, at least by me, at what point that the good professor Diesel built an engine.
The working fuel oil compression engines that were built in Englang subsequent to Herberts patent were not named as Diesel engines. They were given other more generic or builder specific names.
I hope that there are others that can elaborate upon this as the inventor died a bitter and disappointed man subsequent to the media picking up upon the very public, well funded campaign by Professor Rudolf Diesel.
I have no malice towards Professor Diesel however it is well observed that the German aristocracy was very adept at using the media to put their ideas forward.
Me personally, well, I think that the media has always allowed itself to be used and melded by people who understand how powerful it is, though not everyone who understands its power wants to exploit it.
- Herbert Akroyd Stuart is the person you're after. This sort of thing is hardly unusual - who invented what, and who made the most significant advance is often convoluted by claim and counter-claim, and sometimes the "winner" (in terms of who gets the credit) isn't necessarily the strongest candidate. The Wheatstone bridge wasn't invented by Wheatstone, and Snell was 637 years late when he discovered Snell's law. The invention of the laser is a more modern example. See James Burke's old book/TV series "Connections" for a look at a bunch more. --Bob Mellish 17:05, 20 December 2005 (UTC)
Wet cutting (Wet saw)
What is the difference in applications between wet and dry cutting? Such as a wet tile saw, wet concrete saw- when is a wet saw preferable and why is it used? 83.5.231.66 14:16, 20 December 2005 (UTC)
- The water removes the substrate that is cut to get it out of the way and typically works as a coolant for the saw blade. So I guess it's going to be used for cutting harder materials. I'm no saw expert, this is just what I recall from watching This Old House or whatever. - Taxman Talk 16:14, 20 December 2005 (UTC)
- Water or some other liquid is also so used in drilling, where the buildup of material and heat in a deep hole can cause the drill bit and/or the material to fail. Lubricants are fequently used, as they also have the desirable effect of reducing friction. StuRat 02:25, 22 December 2005 (UTC)
Sugar soap
Sugar soap is a chemical used for cleaning. I had never heard of it when I lived in the United States, but then when I moved to Australia I found that its is very commonly available here. Its main use, apparently, is for washing walls, but I wonder about other applications. Perhaps in America it has another name with which I am familiar. Is it dangerous? Are there other cleaners with which it can be mixed, such as ammonia? And, especially, I just gotta know about the name; Why is it called "sugar soap"?
I found Wikipedia about three weeks ago, and now I visit this site more often than google. This is a fantastic, in-depth, resource, and totally uncluttered with capitalistic interests.
Thanks to whoever answers my question.
- We have it in the UK, too. It's a caustic substance, but I can't find its composition. Assume it's sodium hydroxide or something similar. Here's a data sheet (PDF). It's so named because, in its dry form, it looks like granulated white sugar. Chemically, it has nothing to do with sugar. --Heron 19:23, 20 December 2005 (UTC)
- I googled and a some of the results actually had sucrose as an ingredient. [16] Maybe "sugar soap" refers to two different products? —Keenan Pepper 19:39, 20 December 2005 (UTC)
- Ah, there seems to be some confusion. The 'sugar soap' that the submitter is asking about is apparently an abrasive and caustic powder used for cleaning walls. However, the term 'sugar soap' has also been appropriated by various other manufacturers of 'girly' bath and body products—these ones contain moisturizers, vanilla, and other floofy, frilly ingredients.
- The potent, wall-scrubbing 'sugar soap' seems to vary a little bit by manufacturer. (See, for example, powder [17] and liquid [18] formulations.) The important bits seem to be sodium carbonate and sometimes sodium phosphate (caustics), and sometimes sodium silicate (an abrasive); there's also some additional non-hazardous salts that probably are mildly abrasive and/or filler. To find the (hazardous) ingredients in a product, try searching for the product name plus the acronym MSDS. TenOfAllTrades(talk) 19:50, 20 December 2005 (UTC)
What are the physical features at the ocean shore?
They vary widely, from gently sloping sandy beaches, to rocky shores, to steep cliffs. StuRat 02:08, 22 December 2005 (UTC)
Speed of light in a vacuum
How do we know what the speed of light in a vacuum is if we can't even create a perfect vacuum? Would it be possible for a molecule a fair distance away to affect light electromagnetically, or does it physically need to get in the way? Thanks, Zhatt 22:39, 20 December 2005 (UTC)
- You can actually infer its theoretical speed from Maxwell's equations - I think... --HappyCamper 01:30, 21 December 2005 (UTC)
- Right, it's related to the permittivity and permeability of the vacuum by . —Keenan Pepper 02:06, 21 December 2005 (UTC)
- While it's not easy to create good vacuum in laboratory conditions (i.e. on the Earth), the speed of light is much easier to measure using astrological measurements than in a laboratory, and in the space there's already pretty much a vacuum. — Preceding unsigned comment added by B jonas (talk • contribs)
That's not true. It's actually much easier to measure the speed of light in the laboratory. Furthermore, it's possible to create vacuums in the laboratory comparable to interstellar vacuum. However, a perfect vaccum doesn't exist, therefore a perfect measurement of the speed of light doesn't exist either. This isn't much cause for concern, because no measurement anywhere is perfect. The precision of measurements is constrained, even in principle. Finally, with the modern units, the speed of light is a defined exact number, so if you're using the modern units, you're measuring your meterstick, not the speed of light, no matter what experiment you're doing. -lethe talk 12:15, 21 December 2005 (UTC)
- "the speed of light is much easier to measure using astrological measurements than in a laboratory" - no, the only thing you can measure with astrological measures, is the speed of dark (i.e., how long it takes the world to return to the dark ages) - MPF 15:42, 21 December 2005 (UTC)
- If we assume the speed varies at a predictable rate relative to the purity of the vacuum, we could look at the speed of light in a 90% vacuum, a 99% vacuum, a 99.9% vacuum, etc., and extrapolate the theoretical speed at a 100% vacuum. This does assume, however, that nothing "strange" happens near a 100% vacuum. For example, there could be an as yet undiscovered "supervelocity" where the speed of light goes to infinity at a 100% vacuum, similar to superconductivity near absolute zero on the temperature scale. While there is no evidence that such an effect will occur, and no such effect has been measured even in the sparsely populated intergalactic spaces, and no current theory predicts it, anything is possible. Thus, testing with progressively purer vacuums (as we are able to produce them) would eventually enable us to find any such effect, if it exists. StuRat 02:04, 22 December 2005 (UTC)
- Also, don't forget that we know that the speed of light is exactly 299,792,458 meters per second because the definition of the meter is the distance light travels in a vacuum in exactly 299792458-1 second. — Knowledge Seeker দ 03:55, 22 December 2005 (UTC)
- Nothing weird would happen in a 100% vacuum because the only reason a 100% vacuum is needed is so the photons won't crash into anything. The light "thinks" it's in a 100% vacuum all the time - until it crashes. Max 216.209.153.79 14:21, 22 December 2005 (UTC)
December 21
Zinc oxide powder
How much Zinc Oxide should be used in a 4-oz. bottle of body lotion?
- From Google it looks like sunblock usually has between 2% and 10% zinc oxide, so a 4 ounce bottle could have anywhere from 2 to 10 grams. —Keenan Pepper 20:36, 21 December 2005 (UTC)
human body
can you please tell me the differnces between enzymes and hormones? thank you
enzymes generally act locally to facilitate specific processes, hormones usually have a global, systemic effect. The articles on each should have more detail. Night Gyr 05:06, 21 December 2005 (UTC)
An enzyme is a catalyst. A hormone is a signal. alteripse 06:27, 21 December 2005 (UTC)
Pruning of chikoo/sapodilla trees
Would you like to inform me when a subject tree is pruned, it produces significantly low fruit formation in subsequent crop/years. Why? Pl. inform me and oblige. Thanks.
The Chikoo is an evergreen, and thus pruning is not efficient. You should however remove sick or dead parts of the tree. Pruning of buds will for most plants increase yields if done in moderation the next season since the plant will not waste energy on unhealthy or unsuccessfull buds. Overpruning is none to reduce the ammount of fruit and its quality in all plants. Since the Chikoo produces two crops per year and flowers year round pruning saves little energy for the plant. --Sreyan 13:01, 21 December 2005 (UTC)
Freesoft Unicode <-> ASCII conversion tools?
I need a Windows/DOS software tool that allows me to batch convert text files (Unicode, ASCII, DOS/MacOS/Unix line breaks). Thanks! -- Toytoy 07:06, 21 December 2005 (UTC)
Conversion for pressure to altitude
If we know the local ground floor pressure and the pressure at a certain level in a building,how do we calculate the altitude by using the pressure?Is there any practical or empirical equation to calculate the altitude precisely?
- For situations outside, this is quite easy to do. See Atmospheric pressure and Barometric formula. I'm unsure whether these formulas hold when you apply them to interiors of buildings. - Mgm|(talk) 08:57, 21 December 2005 (UTC)
- The obvious answer is 'yes they do, if all the windows are open'. If it's a closed environment, then things are different, and probably depends on what setting the air conditioning happens to be on that day. Proto t c 09:55, 21 December 2005 (UTC)
- Note that this method isn't terribly accurate, as local pressure variations due to winds, solar heating, etc. could throw off the results. This method is fine for airplanes, which only need to stay at a certain altitude with a + or -500 foot variation, but there are other far more accurate ways to measure the height of various floors in a building. StuRat 01:50, 22 December 2005 (UTC)
Convering Word document to PDF
Hi. I am trying to convert a word document to a pdf. I can get it working with a normal white background. However, when I tried adding a background effect and converting, the background effect is lost on the pdf, in otherwords the pdf still has the normal white background. Does anyone know how to fix this? I am using Word 2003, and PDF Maker 7. Thanks. - Akamad 10:17, 21 December 2005 (UTC)
- As far as I know, the Background Effects in Word only works in the Online View. In my version anyway, if you apply a background colour or texture, the view changes to Online View, and if you change it back to Normal View, the effect disappears. The only way to save the file as a PDF is to save the file as an HTML document (File > Save as Web Page), open the result in Internet Explorer or another browser, and then print the "web page" to the PDF Maker. I think you'll be pleasantly disappointed with the results, it looks awful, but that's Microsoft for you... --Canley 12:01, 21 December 2005 (UTC)
- In that case you could try this. Instead of adding a background effect, draw a rectangle over the whole page and add a background image or fill effect to it. Format the rectangle as "behind the text" So that you can read the document then convert to pdf - it might work. Theresa Knott | Taste the Korn 16:36, 21 December 2005 (UTC)
- You could also have a try at opening the document in OpenOffice and saving it directly as a pdf. If you don't have any wacky formatting, it might be easier. - Taxman Talk 18:25, 21 December 2005 (UTC)
- Thanks all for your responses. The method I ended up using was similar to Theresa Knott. Except I didn't know how to fill in a rectangle with a background effect. So I created a blank page with the effect, print screened it, and copy and pasted it in from paint. Once again, thanks. - User:Akamad Merry Christmas to all! 07:10, 22 December 2005 (UTC)
artificial flavors
are the artificial flavors added in food items like potato chips harmful to our health?if so how?thanks
- That depends on how you define "harmful". Cigarettes are sold to millions (billions?) of people every day and they are considered harmful. Many countries have a governing organization that determines what companies can put into food products. In the United States this is handled by the United States Food and Drug Administration. Also see Food coloring. Dismas|(talk) 13:16, 21 December 2005 (UTC)
- It's unknown; some people can develop nasty allergies to flavours/colours such as Tartrazine, Monosodium Glutamate and Aspartame, and no-one knows whether these also affect healthy people. Ironically, the healthier foods, notably 'diet' drinks, can be highest in these chemicals (Aspartame is common replacement for sugar). As to crisps/potato chips however, I'm not sure. smurrayinchester(User), (Ho Ho Ho!) 14:11, 21 December 2005 (UTC)
- This is a topic of hot controversey between folks like the Food and Drug Administration (and, at the risk of sounding biased, nearly all mainstream scientists) on the one hand and various health food advocates and others on the other. Some of our articles, like that on MSG, talk about the controversey. If you're really worried, I'd talk to a local nutritionist; be very wary of what you find on the web, as a lot of the information is put out by people who want to sell (ostensibly) healthier products. --George
- If you are concerned, one option is to use foods with natural flavorings. Many people prefer the taste, anyway. Some artificial flavors, like artificial grape, are nothing like the real flavor, while others, like artificial banana, are quite close. The main reason for artificial flavors is that they are cheaper. However, food is so inexpensive these days relative to it's historic cost that the extra money spent on natural flavors isn't a very significant portion of most families' income these days. StuRat 01:44, 22 December 2005 (UTC)
Arthritis
Hello, I am a student in PA who is currently trying to determine for a paper whether or not arthritis can be caused or helped along by the cracking of knuckles and such during adolescence and younger years. I understand that not all types of arthritis are subject to this kind of damage. I was just wondering if there were any articles that could be sent to me in a link that may help me along. I have been researching this for quite some time and there are so many differing opinions that it is hard to conclude. And since I do not have the resources to conduct an in depth experiment, I am having a difficult time making my paper solid. I believe myself that it is helped along and caused by the cracking of knuckles and cartilage intentionally when younger. However, there are scientists who both agree with me completely or they are completely against the idea and believe it to be preposterous. Any help would be much appreciated! Thank you!--- Chloe
- If I may offer an anecdotal observation.
- In my life, I have only observed a subset of adolescent boys who engage in the knuckle cracking pastime. Perhaps some survey could be conducted to find out what proportion of populations admit to having done this at all, and how heavily.
- Seems to me, arthritis hits men and women equally heavily. I imagine there may be medical statistics out there on proportions of population suffering at what ages.
- Acording to the Wiki article "the disease affects about twice as many women as men". This would lead me to suspect that there may be a relationship with how much milk (calcium) is consumed early in life, since women are susceptible to that bone disease that leads to elderly shoulder problems in later years.
User:AlMac|(talk) 15:25, 21 December 2005 (UTC)
It sounds like you already have found some papers on the topic. Use the references in those papers, and if they are not recent, ask a medical or university librarian (like at a local hospital or university) to help you find more recent papers that have cited the papers you already found. alteripse 00:34, 22 December 2005 (UTC)
Kerberos on pen-and-paper
Is there any Kerberos-like (mutual password-less authentication) protocol that can be used with pen and paper, to provide a basic level of security? —Masatran 13:42, 21 December 2005 (UTC)
- Pretty much any computer security protocol can be implemented with pen and paper using postal mail as a very slow (in comparison to computer networks) transport mechanism. For something practical, that real people could use, you should probably think about what kind of security you're interested in (authentication, protection against eavesdropping, ...). -- Rick Block (talk) 17:12, 21 December 2005 (UTC)
Banging Bolts
Our new office building is driving us nuts with banging bolts [19]
I only could find a couple of references, but as an engineer I found that there were different ideas on how to prevent it. This would be important for psychiatric hospitals! Is it worth doing an article? Does anybody have any more info? --Zeizmic 17:16, 21 December 2005 (UTC)
- Even a short article with that covers the points in the source you provided would be a good thing. I'd never heard of banging bolts but was very interested to read about it. -User:Lommer | talk 18:29, 21 December 2005 (UTC)
- I put up the article bolt banging. Perhaps, it can comfort people :) --Zeizmic 22:39, 21 December 2005 (UTC)
- Our article mentions that it's not agreed how to eliminate the problem. Aren't friction grip bolts an effective alternative, or is the cost to high? For a hostpital the added deflection performance could be handy.--Commander Keane 03:03, 22 December 2005 (UTC)
- One obvious solution is to leave the building unoccupied for a while after it's completed. This would also allow toxins in the new carpet, new paint, new furniture, etc., to vent off before occupants must breathe them, provided these are also put into place as soon as the building is completed. If the expense of an empty building is too much, adding lubricants to the bolt threads to allow them to seat more quickly and quietly might be in order. Some type of oil, which would eventually evaporate and make the bolts "tighter" would be preferable to a graphite lubricant which would leave them loose forever. StuRat 07:20, 22 December 2005 (UTC)
- I really believe this could be the beginning of an adverse trend. Maybe the article could invoke some research, such as a civil lab setup, or post-construction seismic monitoring. I agree that some small modification on the bolts (teflon?) could be the answer. --Zeizmic 12:57, 22 December 2005 (UTC)
Few questions about CRT monitors
How bad is a CRT monitor for our eyes and our health? Should we avoid CRTs or is it not that bad? What kind of trouble does that exactly give to our eyes and our health generally? Does keeping our eyes closer to CRTs create more problems than seeing from normal distance? Is there any time limit per day we may follow for being before a CRTs?
Sounds like a Homework question to me. See CRT
- A lot of the effect of CRTs on eyes is unknown. These questions may never be fully answered, as CRTs are rapidly becoming obsolete, being one of the few remaining vacuum tube technologies. I suspect that in another decade they will have been fully replaced by LCD and plasma flat screen technology. The only thing preventing a quicker change is the cost of the newer technologies, but those will drop rapidly with mass production. StuRat 01:30, 22 December 2005 (UTC)
- Many people have some legitimate ergonomics concerns, like is heavy mouse use (like in computer game playing) more likely to cause carpal tunnel syndrome at a younger age? I work in the profession of lots of people in business sitting most of day in front of work stations, and I have looked into some health issues. I agree that over time this is a moving target.
- Do you have fluorescent lights in the ceiling? Many offices have that. The direction of the lamps in the ceiling relative to the placement of the monitors can have a mutual flicker rate interference that is bad on the eyes ... you better off sitting where those lights are from front to back relative to direction you sitting, not side to side, and not directly overhead, but to your sides, overhead. I not have comparable data on other kinds of lighting such as halogen, but at home I use hallogen pointed up to bounce off white ceiling, so the light is diffused.
- Do you have to wear glasses, or other vision correction? Did you know that just as your glasses cam be set to be the right length when driving, or reading, or whatever, they can also be set for the optimal distance your eyes from the screen?
- There is a science to color contrasts. It is no coincidence that the Telephone Directory uses Yellow Pages (black print on yellow background). Scientific study has shown that, all other things being equal, the easiest on the eyes is black print on yellow background. But this also depends on other stuff around. What color are the walls around the computer monitor you use? Because of this, at home I have a white background text monitor, when I using monochrome stuff (you can manipulate this on your computer settings), and I have light colored walls bahind, above, around my monitor.
- Are you working at a "computer desk?" Traditional desks are designed to be comfortable altitude for you to work with papers and writing on them, but keyboard is somewhat elevated above that, so "computer desks" deliberately have lowered placement for the keyboard, so no strain on user.
- Is your seating comfortable to see the screen and use the keyboard, and get at other papers, or do you end up working hunched over?
User:AlMac|(talk) 09:47, 22 December 2005 (UTC)
SI units and light
Would it be feasible to use SI units when working with the constant speed of light? For example, one µc (micro c) would be about 300 m/s (~670 mph). An nc (nano c) is about 30 cm/s. Zhatt 18:43, 21 December 2005 (UTC)
- Not really. For one, the units are meter and the like, not the prefixes you're mentioning. For two, c is not itself a unit (to which such prefixes are generally applied) but rather a constant rate. For three, the prefix doesn't have any real meaning that I can see when applied to a rate -- what, exactly, is a "nano c"? c/(10^9) lacks this ambiguity. While examples like Kbps exist, it's debateable whether it's K(bps) or (Kb)ps, and the clear physical meaning is present either way. — Lomn | Talk / RfC 19:03, 21 December 2005 (UTC)
- What's the difference between K(bps) or (Kb)ps? I mean, I understand the difference in grouping, but why does it matter—is there any physical or other significance? — Knowledge Seeker দ 22:59, 21 December 2005 (UTC)
- None. It's a distinction without a difference. Raul654 23:03, 21 December 2005 (UTC)
- What's the difference between K(bps) or (Kb)ps? I mean, I understand the difference in grouping, but why does it matter—is there any physical or other significance? — Knowledge Seeker দ 22:59, 21 December 2005 (UTC)
- Oh, yeah, sorry. I meant SI prefix. Zhatt 19:05, 21 December 2005 (UTC)
- I don't see how µc (or, for that matter, kb/s) would be any more "ambiguous" than perfectly ordinary prefixed speed units line, say, km/h. Certainly you can parse that as either k(m/h) or (km)/h, but it's the same unit either way. SI prefixes are applied to derived units, including units of speed, all the time. Applying them to nonstandard units like c is no more silly than using units such as attoparsecs. —Ilmari Karonen (talk) 19:13, 21 December 2005 (UTC)
- I'll cite from your linked article: bits of dry humor combined with putative practical convenience. If that's a rationale for feasibility, then by all means, proceed. — Lomn | Talk / RfC 19:48, 21 December 2005 (UTC)
- I don't see how µc (or, for that matter, kb/s) would be any more "ambiguous" than perfectly ordinary prefixed speed units line, say, km/h. Certainly you can parse that as either k(m/h) or (km)/h, but it's the same unit either way. SI prefixes are applied to derived units, including units of speed, all the time. Applying them to nonstandard units like c is no more silly than using units such as attoparsecs. —Ilmari Karonen (talk) 19:13, 21 December 2005 (UTC)
- I can see it having some practical convenience. When talking about astrophysics and the like, I offten hear the phrase a fraction of c come up. Instead of saying zero-point-zero-zero-one cee, or a thousandth of a cee why not just say mili-cee? Zhatt 20:05, 21 December 2005 (UTC)
- I think I erred in using "rate" as the example when I referred to c as a "constant rate"; my personal objection derives from c as a constant. I find the thought of a decapi equally silly, despite the fact that such a number does exist and could be referred to. — Lomn | Talk / RfC 22:03, 21 December 2005 (UTC)
- It's not like you can't take a multiple of a rate, I mean you could take a µδ(fn)/δt (a 'micro' derivative if you will) but all you'd be doing is multiplying an ordinary differential, by a constant µ, hence µ x δ(fn)/δt, which is, kind of silly--Aolanonawanabe 22:12, 21 December 2005 (UTC)
- I think I erred in using "rate" as the example when I referred to c as a "constant rate"; my personal objection derives from c as a constant. I find the thought of a decapi equally silly, despite the fact that such a number does exist and could be referred to. — Lomn | Talk / RfC 22:03, 21 December 2005 (UTC)
- I can see it having some practical convenience. When talking about astrophysics and the like, I offten hear the phrase a fraction of c come up. Instead of saying zero-point-zero-zero-one cee, or a thousandth of a cee why not just say mili-cee? Zhatt 20:05, 21 December 2005 (UTC)
I've been thinking about this for a while and I wasn't really convinced by the explanations above. I'd have to say that there is no inherent reason that one couldn't combine a prefix with a rate and so on. I think Lomn is on to something: we think of c as a constant and it does seem odd to use the prefix. The π example is telling as well. You're right that since we often specify speeds that are fractions of the speed of light, the prefixes might be useful. But even if there were some geometric situation in which one-tenth of π were used frequently, I'd probably still want to use 0.1π rather than dπ. It somehow feels different with constants or measurements compared to units of measurement. But I think the main obstacle for me, surprisingly, is pronunciation. Perhaps it's just the way I think, but when I see "5.5 mm" I hear "millimeter" in my head, not "em em". I hear "microliter" instead of "mu ell" (although I've occasionally said "kay gee" for "kilogram". But the point is, I wouldn't know how to read μc. Certainly not "mu see". "Micro see"? "See" is the name of the symbol, not the unit. And of course "micro the speed of light" is ridiculous. I'd probably read it as "one hundredth the speed of light" or "point one see" and therefore I write it "0.1c". Now if a unit of velocity were defined such that one unit was equal to c, the speed of light in a vacuum, that would be a different story. The distinction is subtle, but significant. For instance, regarding the atomic mass unit, written "amu" or now "u", I would never think to write "k·amu" or "ku" even if the abbreviation "u" for "atomic mass unit" were more prevalent. However, I routinely use "kDa" (kilodaltons), where one dalton is equal to one mass unit. Not sure if this helps, but this I think is why the idea doesn't sit well with me. — Knowledge Seeker দ 10:29, 22 December 2005 (UTC)
- I understand now. At the start I thought that c or constant would be a bad term to use. Like you said, we need to somehow make up a unit for the speed of light in a vacuum. lv? Two µlv = 599.6 m/s? Needs work, but thanks. Zhatt 18:34, 22 December 2005 (UTC)
It's perfectly acceptable to have a unit defined in terms of a constant. That is, after all, what a light year is. Astronauts frequently speak of milli-g gravity, which means one one thousandth of the constant g. No reason why one couldn't also speak of µc, millionths of the speed of light. -lethe talk 21:51, 22 December 2005 (UTC)
How much do celectial objects affect gravity on earth?
Because we have the moon, sun, and planets, each with their own gravity, and these objects move in relation to the earth, one would expect "down" as given by a plumb bob to vary. How much does this "down" vary? One would also expect the weight of an object with given mass (but kept in a constant ___location on earth) to vary. How much would it vary? --Juuitchan
- You have just described tides. —Keenan Pepper 20:25, 21 December 2005 (UTC)
- The effect is quite minimal, and is only obvious in the case of tides because the total amount of water in the oceans is so vast. It's like we are zoomed in on the very top of a bar graph which has a microscopic sinusoidal change in height. Other forces which affect little g, the acceleration due to gravitiy on Earth, (such as the elevation, centripetal force, and local variations in density) can have more effect than the tides. StuRat 01:24, 22 December 2005 (UTC)
- There are effects of gravity on the Earth's orbit from the Moon, as well. -- Natalinasmpf 01:59, 22 December 2005 (UTC)
Venus
Im trying to find info about Very Extensive Non-Unicast Service ? I see it come up on Comptia test questions at times.. But trying to learn what VENUS is.. Is not easy. Thanks
unsigned post by 204.9.144.54. Modified by Zhatt 20:39, 21 December 2005 (UTC)
High fructose corn syrup
Is High fructose corn syrup a distinct foodstuff from corn syrup? It used to be a redirect to corn syrup, then an anon created High Fructose Corn Syrup and redirected to it instead. I moved the new article on top of the lowercase version. Right now there is a slight duplication of content between corn syrup and high fructose corn syrup. -- Curps 21:53, 21 December 2005 (UTC)
- As the article says, an industrial process is used to convert most of the starch and glucose into fructose, which is much sweeter. They are substantially different products. —Keenan Pepper 05:49, 22 December 2005 (UTC)
Chemical Reactions and Exponential Growth
Are there any household chemicals whose reactions with other household chemicals would be examples of exponential growth? (This is a homework question, but I have to do experiments and stuff after I figure out which chemicals will do this, and figuring out the chemicals on my own was not a requirement, because the point was the exponential growth, because it's math homework.) 216.174.52.184 22:50, 21 December 2005 (UTC)
- Perhaps the spontaneous combustion of a pile of oil and gasoline soaked rags ? DON'T TRY THIS AT HOME ! StuRat 01:13, 22 December 2005 (UTC)
- Exothermic chemical reactions are not so much exponential than a feedback loop (ie. due to Brownian motion there is a tad of uncertainty in predicting the rate of reaction), since regular combustion is at a steady rate, not an exponential consumption of fuel. Perhaps nuclear fission is a better alternative? :D -- Natalinasmpf 01:31, 22 December 2005 (UTC)
- I think the nuclear fission example is quite similar. That is, in both cases, energy from the earlier reactions drives the future reactions, at an ever increasing rate, until the energy is dissipated or the fuel is used up. StuRat 03:24, 22 December 2005 (UTC)
- I really meant the exponential reaction in an atomic bomb, not a nuclear reactor, which is not exponential. In both a nuclear reactor and controlled combustion (ie. a fireplace), the rate of energy being released is linear, not exponential. Perhaps a forest fire, on the other hand... -- Natalinasmpf 10:54, 22 December 2005 (UTC)
- In both the cases of spontaneous combustion of a pile of rags and a nuclear weapon, energy feedback is important in creating exponential growth. In the case of the rag pile, the outer rags insulate the inner rags, and prevent thermal energy from leaving the system. Thus, this thermal energy becomes feedback into the system and increases the rate of combustion, thus releasing more thermal energy, which in turn causes faster combustion, and so on, until the pile bursts into flames and is able to vent heat normally. At this point the growth is no longer exponential. StuRat 22:34, 22 December 2005 (UTC)
- DNA, carbohydrates, and proteins will readily demonstrate exponential growth. Grow some yeast, or possibly fruit flies. ‣ᓛᖁ♀ᑐ 02:01, 22 December 2005 (UTC)
- Oh yes. Polymerase chain reaction. How could I forget? -- Natalinasmpf 03:56, 22 December 2005 (UTC)
He/she did ask for household chemicals. I only point it out because I'm curious myself. Jasongetsdown 20:01, 22 December 2005 (UTC)
- Agreed. That's why I suggested the spontaneous combustion of oil and gasoline soaked rags. These are household chemicals, or at least, garage chemicals. The safety issue could be handled by putting the rags in an outside fire pit or barbeque grill, attaching a digital thermometer to the center, and monitoring the temp continuously until the maximum temp is reached. Note that whether it bursts into flames is dependent on many factors, such as the ratio of oil to gasoline, the level of ventilation allowing oxygen from the air into the combustion area, and the outside temperature. Hopefully some rise over the ambint temp can be observed, although it will only actually burst into flames under ideal conditions. The growth of bacteria in a plate of apple juice would be more reliable, but is moving into the area of biology (in addition to chemistry, not in place of it) and is more difficult to measure. StuRat 22:47, 22 December 2005 (UTC)
Pregnancy
What are the odds of a woman that recently gone off birth control would get pregnant if they recently had sex?
- It depends on age of the woman, fertility before use of birth control, type of birth control used, time since it was discontinued, number and regularity of menstrual periods since discontinuing it, how many times since then she has had sex, when in relation to the last menstrual period she has had sex, and the fertility of the male(s). If you supply those factors we might might be able to guess odds. alteripse 00:30, 22 December 2005 (UTC)
- Might I assert, though, that no matter what, the odds are too good to assume that she won't get pregnant. If it's very recent (say, last 72 hours), the emergency contraception pill might be in order? --ParkerHiggins ( talk contribs ) 20:12, 22 December 2005 (UTC)
DNA
Describe the steps in the synthesis of a polypeptide?
If you don't realize that DNA is not a polypeptide, we need to start with some real basics, don't we? DNA is a polynucleotide, a chain of nucleotides. A polypeptide, a chain of amino acids, and the most important natural polypeptides are proteins. The sequence of nucleotide bases in the DNA of a gene carries the information for making one protein (one polypeptide). When something activates the specific gene, the DNA base sequence is transcribed to RNA, which is a one-stranded polynucleotide. RNA moves out of the nucleus, into the cytoplasm of the cell, and attaches to a ribosome, which is like a tiny machine that translate the RNA into a polypeptide by joining amino acids together into a chain. For a bit more detail, see protein biosynthesis. alteripse 00:26, 22 December 2005 (UTC)
Ah, then this all leads up to structural biology. -- Natalinasmpf 01:29, 22 December 2005 (UTC)
December 22
Zinc lozenges
What property in zinc causes it to make you ill if you take zinc lozenges on an empty stomach? I had a cough and took a zinc lozenge (the instructions on the package say to take them with a meal), and went to make breakfast, but found I didn't have any milk, so I drove to work to pick something up at the cafeteria at work, but by the time I got to work, my stomach was cramping up and I was sick to my stomach. Zoe (216.234.130.130 00:45, 22 December 2005 (UTC))
- The active ingredient of zinc lozenges is usually zinc gluconate, with a little glycine added. I am not sure how to answer your question of "what property" can nauseate you. I am reminded of Moliere's doctor who answered a similar inquiry into how a sleeping medicine makes you sleepy with "by its dormitive property". So the answer would be, zinc gluconate made you sick at the stomach by its nauseant tendency. Hope you're feeling better soon. alteripse 01:14, 22 December 2005 (UTC)
- I suppose there is an answer, but it might not be known. For example, it may act as a catalyst in a reaction which leads to a chemical product which blocks a nueroreceptor responsible for limiting the secretion of hydrochloric acid, thereby changing the pH of the stomache beyond it's "comfort range". I made that all up, just to show what the chain of events might look like, if it was known. StuRat 03:17, 22 December 2005 (UTC)
Laser Computer Game
There was a simple 2-D computer game I used to play in the mid-90s that involved redirecting a laser light around various obstacles using mirrors, so that the light hit a target. It was kind of like the Incredible Machine, because first you set up the configuration, and then you pressed the "run" button to see if it would work. Does anyone remember the name of the game, and perhaps where I could find it? -Jian
- Sounds like Deflektor? I played it on the Amiga, you can download the game for the PC for free quite easily, just do a search. --Canley 03:02, 22 December 2005 (UTC)
- I remember playing a game like that, called simply Laser Light. —Keenan Pepper 05:30, 22 December 2005 (UTC)
- I believe the game you are looking for is called Laser Chess. Zhatt 19:46, 22 December 2005 (UTC)
index
- Hmm. Index? --AySz88^-^ 02:52, 22 December 2005 (UTC)
- I prefer IndeX! myself, but that's just a personal preference--Aolanonawanabe 03:09, 22 December 2005 (UTC)
In a fight who would win, an elephant or a lion?
- Neither, obviously godzilla would intervene to on behalf of the elephant--Aolanonawanabe 03:12, 22 December 2005 (UTC)
If we are talking about an adult elephant, then definitely the elephant. Lions don't mess with them. One stomp or goring with a tusk could kill a lion instantly. A lion's method of killing, breaking the neck of the prey, would be completely ineffective against an elephant. It couldn't reach an elephant's neck, and even if it could, it couldn't get it's jaws around it, and if it could, it still couldn't break it. StuRat 03:12, 22 December 2005 (UTC)
- From what I remember, before a lion can brake somethings neck, it first must trip it while its running away. I doubt a lion would be able to trip an elephant, running our not. Zhatt 06:21, 22 December 2005 (UTC)
- Yes, the lion must brake (stop) them, before it can break (fracture) them. And how is an lion going to stop an adult elephant going at breakneck speeds ? StuRat 07:02, 22 December 2005 (UTC)
- It is also true that lions (and tigers in Asia) will take baby elephants - still not an easy task, as they have to make sure the adult elephants are not too close by MPF 11:02, 22 December 2005 (UTC)
- This is quite risky to the cats, as elephants, unlike most herd animals, will attack the cats who are attacking the baby elephant. They also will form a defensive circle around the baby elephants, if they perceive a danger to them. A lost baby elephant, however, might fall prey to the big cats. StuRat 22:26, 22 December 2005 (UTC)
Time symbol
I came across a number with a time symbol after it, but I do not know what the symbol stands for? Here it is: 32.9(14) a
- It probably means year: "This is the normal meaning of the unit "year" (symbol "a" from the Latin annus, annata)" --Borbrav 03:43, 22 December 2005 (UTC)
fundraising banner?
I can't help notice from time to time when I load a page I wind up getting <div id="fundraising" class="plainlinks" style="margin-top:5px; text-align: c, instead of actual content, not terribly important, but is this some kind of glitch in the scripting for the banner?--Aolanonawanabe 03:18, 22 December 2005 (UTC)
- It looks fine to me. Perhaps you'd like to refresh the entire page (Shift+Ctrl+R in Firefox, Ctrl+F5 in IE). enochlau (talk) 05:52, 22 December 2005 (UTC)
- on a side note, the server was just down for 10 minutes and the only thing working was the banner (:--Aolanonawanabe 06:07, 22 December 2005 (UTC)
A.I.D.S
how come we have found the cure for other viral diseases but not AIDS? And what exactly happens when HIV is injected into a person?thanks
- It's only been around for 20 some years, which isn't much time. Most diseases were studied far longer than that before a cure was found. Also, some viruses seem to mutate more than others, making cures harder to find. On the conspiracy theory side of things, one could argue that pharmacuetical companies aren't interested in investing billions of dollars in finding cures, which would be unlikely to offer a return on investment. A treatment that keeps people with AIDS alive, but requires expensive meds for the rest of their life, is far more likely to be profitable. Thus, the big drug companies invest their money there. StuRat 05:39, 22 December 2005 (UTC)
- Conspiracy theories aside, keep in mind that we don't actually have a cure for many viruses, including (notoriously) the common cold. Usually the immune system kills the virus on its own, but HIV attacks the immune system itself. If HIV destroys your immune system then you have nothing with which to fight back. —Keenan Pepper 05:42, 22 December 2005 (UTC)
- I agree that once any disease, such as AIDS or leukemia, has completely destroyed the immune system, there is not currently much hope, short of a transplant of portions of the immune system (like bone marrow or stem cells) from compatible healthy individuals. However, it takes years for AIDS to completely destroy the immune system, and this point may never come for many on the latest drug "cocktail" treatments. This would allow ample time for a cure to be administered, if one existed. StuRat 06:57, 22 December 2005 (UTC)
What is Space-Time?
- Spacetime is a concept that involves both space and time considered together, because in special relativity (and general relativity) it doesn't make sense to consider them separately. —Keenan Pepper 05:34, 22 December 2005 (UTC)
physics
How is it that when we apply brakes to a car only the upper portion of our body moves forward whereas our legs remain in the same position?
- Due to inertia, all parts of our body actually want to move forward. However, our legs while sitting are in contact with the chair, and there is friction between the legs and the chair that stop that part sliding forward. However, there's nothing to stop the top part of your body from moving forward (except for the seat belt but there's a bit of slack in that). enochlau (talk) 05:51, 22 December 2005 (UTC)
- Also your feet or at least one of them are pressing against the brake pedal and therefore you are pushing back. Dismas|(talk) 06:40, 22 December 2005 (UTC)
- That's a very good question. I agree with the above users. I'd guess that it's a combination of three factors. One, you'll automatically brace yourself with your feet against the floor, which will hold back your whole body but won't stop you from bending at the waist. Especially because much of this force is directed along the axis of your leg, it doesn't require as much effort and is less noticeable. Secondly, the friction of your body against the seat also makes it harder to move, although again it doesn't stop you from bending at the waist. Third, the lap belt over your waist will do the same. To hold your upper torso in place are a couple factors. One, you tighten your abdominal muscles but since this is not an action you do routinely (like stabilizing with your legs), it is more noticeable. Also, wearing a shoulder belt will help hold you in place, but as Enochlau noted, shoulder belts usually give slack unless they are tightened sharply. Finally, you may brace yourself with your arms if you are being driven by a particularly reckless driver. — Knowledge Seeker দ 07:33, 22 December 2005 (UTC)
- Also your feet or at least one of them are pressing against the brake pedal and therefore you are pushing back. Dismas|(talk) 06:40, 22 December 2005 (UTC)
Electrical and Electronic devices!!
Dear Sir
- I would like to know what is the difference between Electrical and Electronic Devices?
- Plz Answer the question in simple words without using too much of scientific terms!!
- An electrical device is any device that uses electricity. A hair dryer, a washing machine, an electric fire, a torch and so on.
- An electronic device uses transistors and other electronic components. They are complicated and small and usually low voltage. Electronic devices are obviously electrical devices. A computer, a radio, a mobile phone, a digital clock are all electronic devices. It's a matter of complexity really. Theresa Knott | Taste the Korn 08:08, 22 December 2005 (UTC)
- Basically, electronic means it uses small amounts of electricity to carry information; electric (or electrical) means it uses electricity in larger amounts as a power source. This is a simplification, but you wanted simple. It's like the difference between putting a bit of black ink on a page to write a message, and painting a window black to shut out the daylight. --Anonymous, 11:00 UTC, December 22
Physical and biochemical effects of being reversed
Many years ago, I read an entertaining science fiction short story by my favorite author, Isaac Asimov. In it, a character is removed from our three-dimensional universe into a fourth one; he is later returned. It is easy to prove his journey to a skeptic: when he was returned, he was returned in the opposite orientation. His heart now beats towards the right, his appendectomy scar is now on the left, and so on (I don't remember the details, but you get the idea). I find this quite plausible; I have no difficulty imagining a two-dimensional being (such as a Van Gogh's Starry Night) being removed from a two-dimensional universe into our three-dimensional one, then being returned "upside down" so that it would seem to be mirror-reversed to the other 2-D inhabitants.
I wonder, though, if there would be any other effects. It seems obvious to me that our traveler would be aware of the change, as he would now see everything flipped. That is to say, he would have no difficulty navigating his world, but writing would now be flipped, his house would have the living room on the left instead of the right, and so on—it would be as if someone had mirror-imaged his entire universe. There are two issues I'm less sure about. One, would there be effects related to physics? I seem to recall that some particles or laws of nature are not equivalent when reversed in a mirror. I lack the knowledge to understand or grasp this, and perhaps it is not yet possible to guess at the nature of the effect on our friend.
My bigger question is wondering about the biochemical effects. While stereoisomers have no effect in basic chemical reactions, the enzymes in our bodies are stereospecific. For the most part, we use D-sugars and L-amino acids. Our friend's sugars, amino acids, and enzymes would all be flipped. The enzymes would have no trouble metabolizing the molecules already present in his body. Oxygen and water are symmetric and would pose no problem. But how about something like glucose? The glucose in his body would be L-glucose, right? If he were to ingest D-glucose, it would look like L-glucose to him. Would his enzymes be able to use it in reactions? Would they be able to break down a peptide bond between two "D"-amino acids? In short, would he be able to derive energy and raw materials from food? He may have some enymes able to react with a couple molecules but I can't imagine it would be sufficient. It seems to me that such a reversed person would slowly starve to death, unless some dedicated person worked to synthesize the appropriate nutrition. Apologies for the long post. Am I way off? Anyone have any idea? — Knowledge Seeker দ 10:54, 22 December 2005 (UTC)
- Wouldn't those enzymes be mirrored as well? - Mgm|(talk) 12:43, 22 December 2005 (UTC)
- I wonder if this story wasn't actually The Reversed Man, also titled Technical Error, by Arthur C. Clarke... in which the reversed man finds himself slowly starving for exactly the reason described. --Anonymous, 11:05 UTC, December 22
- I think the most immediate problem would be finding enough isoleucine, threonine, and tryptophan (chiral essential amino acids), without which he will suffer from protein-energy malnutrition and pellagra eventually. Carbohydrates shouldn't be a problem, and should prevent starvation at least long enough for him to get scurvy due to a lack of D-ascorbic acid. A few other vitamin deficiency disorders might also arise, such as anemia. ‣ᓛᖁ♀ᑐ 13:27, 22 December 2005 (UTC)
- Why do you say carbohydrates shouldn't be a problem? I thought L-glucose, for example, was indigestible? —Keenan Pepper 16:52, 22 December 2005 (UTC)
- There are plenty of other carbohydrates that would be digestible, no? ‣ᓛᖁ♀ᑐ 17:46, 22 December 2005 (UTC)
- For example in rats, L-fructose provides about 6 kJ/g, while L-gulose provides about 11 kJ/g, apparently via intestinal flora. [20] Our hyperdimensional traveler should be able to survive on fruit. ‣ᓛᖁ♀ᑐ 18:14, 22 December 2005 (UTC)
- Thinking about this some more, he'd better stay away from glucose entirely, which may be very difficult. After returning to 3D, all of his bacteria will be reversed, but it won't take long for him to pick up fresh colonies of normal bacteria. Presumably he'll be very safe from infection while the old bacteria starve and the new bacteria try to settle in, but undigested sugar will probably make him seriously ill once the latter are established. ‣ᓛᖁ♀ᑐ 18:50, 22 December 2005 (UTC)
- That's an interesting point, actually. Having a gut full of starving intestinal flora probably isn't good for you either. The loss of all those symbiotic bacteria isn't going to protect him from infection; it's going to make him more vulnerable—unfriendly, opportunistic infections won't face the usual competition. TenOfAllTrades(talk) 18:59, 22 December 2005 (UTC)
- Yes, he may need to be very careful to prevent normal bacteria from outcompeting his gut bacteria. Oughtn't it be very difficult for normal bacteria to infect reversed tissue, though? ‣ᓛᖁ♀ᑐ 19:38, 22 December 2005 (UTC)
- From a purely physical standpoint, only the weak nuclear force violates parity. I don't think the weak force is important to the functioning of the human body, so he should be okay if he can just find stuff to eat. —Keenan Pepper 17:06, 22 December 2005 (UTC)
- By the way, it might not be necessary to flip yourself through some four-dimensional space to achieve reversal. It may turn out that our universe is non-orientable, in which case you would just have to make a very long journey along an orientation-reversing path. Dmharvey 19:07, 22 December 2005 (UTC)
- Similar to an Alice universe? The scenario in that article is more extreme; matter might become antimatter and vice versa. ‣ᓛᖁ♀ᑐ 19:38, 22 December 2005 (UTC)
Note that there is a condition where a person is born with all their organs mirrored just as described. However, molecules are not reversed. This condition does not seem to be harmful, although doctors using a stethoscope or performing surgery on such a person must be aware of it so they can find the organs in the proper place. If someone knows the name of this condition, I would like to know it. I would also like to know the cause of this condition, if known. StuRat 22:15, 22 December 2005 (UTC)
- That's situs inversus. Situs ambiguus is any abnormal organ positioning, and dextrocardia affects only the heart. Heart disease is somewhat more common with situs inversus totalis (all organs reversed), and almost certain if the heart ends up on the wrong side. ‣ᓛᖁ♀ᑐ 22:29, 22 December 2005 (UTC)
- "Writing would now be flipped" : his, or what he sees ? Gardner wrote a book about parity, The Ambidextrous Universe: Mirror Asymmetry and Time-Reversed Worlds. A baby does not care if it is a left or right breast ; the brain can learn and it is more and more difficult to learn something contrary. See for yourself ... Harvestman 22:35, 22 December 2005 (UTC)
- Both. His writing would look normal to him, but be backwards for everyone else; while everyone else's writing would look normal to them, but backwards to him. StuRat 01:27, 23 December 2005 (UTC)
Chirality
- What are all the chiral essential nutrients?
- Which are commonly found in nature? ‣ᓛᖁ♀ᑐ 13:30, 22 December 2005 (UTC)
reptiles
can reptiles like snakes sweat and shiver???Why are they called cold-blooded animals?
- have you checked the reptile article? or the snake one? or the sweat one? Boneyard 11:22, 22 December 2005 (UTC)
- Reptiles are called cold-blooded because they produce very little body heat; their metabolism relies mainly on the temperature of their environment. They do have some control over their body temperatures, though, including:
Only a few mammals have sweat glands. Cats don't, for example. People and horses do, on the other hand. StuRat 22:06, 22 December 2005 (UTC)
SUN
How far is the sun from the earth
It is about one astronomical unit, or 93 million miles, or eight light minutes away. The entire astronomical culture based on this distance. ;-) -- Natalinasmpf 11:15, 22 December 2005 (UTC)
- The distance varies a bit over it's orbit, since the orbit is elliptical, not circular. See the Earth article for the details, particularly noting the info in the template on the right side of the article. StuRat 11:27, 22 December 2005 (UTC)
- Yes, that is why I said "about". ;-) -- Natalinasmpf 11:32, 22 December 2005 (UTC)
- Yes, and that's why I pointed them to the exact answer. :-) StuRat 11:43, 22 December 2005 (UTC)
tsunami?
(No specific question was posted.)
See the tsunami article for a definition of a tsunami, which is often mistakenly called a tidal wave. StuRat 11:43, 22 December 2005 (UTC)
- If you mean the Tsunami, see 2004 Indian Ocean earthquake. smurrayinchester(User), (Ho Ho Ho!) 16:24, 22 December 2005 (UTC)
regarding drugs
HELLO AM NARESH AM A MEDICO IN OSMANIA MED COLLEGE I HAVE A SEMINAR ON "USAGE OF SAFE AND PROPER DRUGS" PLEASE HELP ME IN GIVING SOM POINTS THANK U
Basics of drug use: 1. Right drug 2. Right dose 3. Right time 4. Right patient
These are obvious basics but failure to deliberately ensure each of these points leads to most medication errors and most injuries of people by their medical care. alteripse 12:15, 22 December 2005 (UTC)
- I would add:
- 5. Right combination with other drugs the patient is taking (no negative interactions).
- 6. Right delivery method (time-release or immediate acting, pill vs. injection, intramuscular injection vs. intravenous injection, etc.).
- 7. Ramp it up. Unless a specific dosage is needed to treat a crisis, start with a low dosage to check for side effects, allergic reactions, etc., then gradually increase the dosage until the minimal level is found which is safe and effective.
- This is absolutely untrue for some drugs and some conditions and does not belong in this list of universals. HINAD.alteripse 22:14, 22 December 2005 (UTC)
- I listed an exception for a crisis situation. Do you know of any other exceptions where starting with a low dosage and ramping it up is not indicated ? A good example of a drug to ramp up is a pain reliever, where the absolute minimum needed to manage pain should be given, in order to limit side effects and avoid dependency. StuRat 00:10, 23 December 2005 (UTC)
- Also, some common sense is needed. Waking patients to give them a sleeping pill makes no sense, for example. Neither does giving insulin to a diabetic who currently has a low blood sugar level. StuRat 13:27, 22 December 2005 (UTC)
Hi Naresh, Osmania University Hyderabad? Dominick (TALK) 13:19, 22 December 2005 (UTC)
fire
Can fire be considered as a gas?
- No. It's a plasma, which is a distinct state, not usually considered to be a solid, liquid, or a gas. Although, if you had to choose between them, it is closer to a gas than the other two. StuRat 13:12, 22 December 2005 (UTC)
- Fire is not a plasma, it's a(n exothermic) reaction, not matter. Max 216.209.153.79 14:39, 22 December 2005 (UTC)
- If flame were made of plasma, wouldn't it be affected by a magnetic field? I just held a fairly strong permanent magnet near the flame of a lighter and nothing happened. —Keenan Pepper 16:20, 22 December 2005 (UTC)
- The Straight Dope is that ordinary fire isn't plasma.
- I would say fire refers to the whole process of combustion, as Max said, and flame refers to the body of incandescent gas (with only very few charged particles, not enough to qualify as plasma). —Keenan Pepper 16:32, 22 December 2005 (UTC)
- I use "fire" and "flame" synonymously, with "combustion" used for the more general case of any oxidation. This avoids having to say that digestion, which involves oxidation of food, is a "fire in your digestive system", which just sounds wrong.
- I stand by my assertion that it's a plasma, although a weak one, as does our plasma article. One test is that it's more electrically conductive than normal, non-ionized gases. I would also think that a powerful enough magnet would affect it. You might need one on the order of strength used in particle accelerators to see the effect, however.
- Specifically, it's a type of cold plasma, which have a low percentage of ionized atoms. The word "cold" is a bit misleading, as it's only cold relative to a hot plasma, like that in the Sun. Warm plasma would have been a better term, since ultra-cold plasma could then be simply called cold plasma, but we are stuck with the terms we have. StuRat 21:39, 22 December 2005 (UTC)
cancer
hello my friend has breast cancer.she has been under treatment for the past 2 weeks.she doesnt tell me how serious it is.can you tell me what the chances that she will live?thank you
- No we can't, for several reasons. I'd suggest you to talk this through, explain how worried you are and etc. ☢ Ҡieff⌇↯ 13:13, 22 December 2005 (UTC)
It depends on the type of breast cancer and how far it has spread. If it has metasticized to the lymph nodes and several other organs, it's a virtual death sentence. If it is contained to one small lump, near the surface, it may be very treatable. StuRat 13:20, 22 December 2005 (UTC)
- If you're in the US, you can call 1-800-4-CANCER or go to [21] to do a live chat with a Cancer Information Service specialist. This is a program of the National Institutes of Health (through the National Cancer Institute), so they have lots of FREE information they can provide and are not commercial in any way. --Quasipalm 17:17, 22 December 2005 (UTC)
- In case you live in Australia, this site provides information about support centres. User:Akamad Merry Christmas to all! 22:18, 22 December 2005 (UTC)
basic concepts of server administration
what is basic concept of server administration.
how its work?
how we maintanance.
- The basic concept is: 1) Ensure hardware is functioning. 2) Ensure user needs are being met. 3) Ensure security issues are being fixed.
- Now, how do you do all that? --Kainaw (talk) 15:15, 22 December 2005 (UTC)
- See also: BOFH. —Ilmari Karonen (talk) 15:24, 22 December 2005 (UTC)
Why are there few mammals native to oceanic islands? Is this an example of an edge effect? ‣ᓛᖁ♀ᑐ 15:41, 22 December 2005 (UTC)
- It's because those animals couldn't make it there on their own. I'll give you two good examples to think about: rabbits in Australia and rats in Hawaii. These animals were only brought there fairly recently due to human exploration, but they absolutely took over. The simple reason they weren't already native to those islands is because they couldn't get there until we (unknowingly) took them there in our boats. --Cyde Weys talkcontribs 15:59, 22 December 2005 (UTC)
- Also note that many oceanic islands are rather new (compared to the age of the continents). So, it isn't like an island full of animals drifted away from the coast. The island built up from the ocean floor and eventually broke through the surface of the ocean. --Kainaw (talk) 19:14, 22 December 2005 (UTC)
- This is true for volcanic islands, which are the vast majority of islands. Note that islands are also sparsely populated with other animals, like reptiles. Unless creatures can swim or fly, they rarely could arrive on the island on their own. Amazingly, some land animals do seem to have somehow arrived, possibly a pregnant female on driftwood after a hurricane. Darwin particularly studied how the few varieties that arrived on the Galapagos Islands evolved to fill all the ecological niches in the island, which were left vacant by absent species. This is also true of the largest island continent, Australia. There marsupials evolved to fill the gaps left by the absence of placental mammals. StuRat 21:07, 22 December 2005 (UTC)
- True. there are also earthly planets without placenta mammals because we did not get there yet. --Harvestman
SQL question
I haven't used SQL for awhile and I'm a bit rusty. Here's the problem I'm trying to figure out the best way to solve:
I have a table of data (tbl_data) and a table of keywords (tbl_keywords) which are connected to each other through a joining table which keeps all of their one-to-many links straight (join_data_keywords). This all works fine.
What I want to do is filter the results in the data table by keywords. I can get it to do this very easily using an OR operator (for example, I can have it SELECT entries which have either or both keywords A and B associated with them), but I cannot seem to figure out the best way to do this with an AND operator (i.e., SELECT only entries which have both keywords A and B associated with them, but not just one or the other).
I've figured out a way to do this with DCount function calls (this is in MS Access), but it is very slow and not very elegant. I thought UNION might help but it also seems to use OR rather than AND as its method. I suppose I could join a number of IN with additional statements inside them -- but is there a better way to do this? Hopefully the above will be somewhat comprehensible to someone who knows about SQL... --Fastfission 18:38, 22 December 2005 (UTC)
- Actually... the joining of IN statements seems to have worked out fine, so it looks like I answered my own question. --Fastfission 18:46, 22 December 2005 (UTC)
- Assuming your mapping table has a unique key on data/keyword combinations, you can count the number of rows matching your 'or' comparison. For example: "select count(*) as cnt from join_data_keywords where keyword='keyword 1' or keyword='keyword 2'" If cnt is 2, you got 2 hits (one for each word). If you had 3 keywords you were checking for, you'd want a return of 3. Some SQL databases will let you get it all in one query as "select *, count(*) as cnt from join_data_keywords where (keyword='key1' or keyword='key2') and cnt=2" --Kainaw (talk) 19:12, 22 December 2005 (UTC)
- That's a clever approach, thanks. I forgot all about COUNT. --Fastfission 01:13, 23 December 2005 (UTC)
Anteater's closest extant relative?
I'm wondering, what is the anteater's closest extant relative? Extinct species don't count. Thanks! --Cyde Weys talkcontribs 15:54, 22 December 2005 (UTC)
- According to Xenarthra, the anteaters are a family, and the other families in the order Xenarthra are the sloths and armadillos. —Keenan Pepper 16:26, 22 December 2005 (UTC)
- Man can eat ants also. Plenty of animals do. As for a diet, I would suggest add some lettuce and brown sugar. --Harvestman
Treatment of mental illness
How do you treat/cure gays? Can it be done with therapy, or do they need mental medication to make them normal? -- ~ ~~
- According to the American Psychological Association, Psychologists, psychiatrists and other mental health professionals agree that homosexuality is not an illness, mental disorder or an emotional problem. See also Homosexuality. Dmharvey 20:34, 22 December 2005 (UTC)
- Agreed. They classify it as a normal variation in human behaviour, not a mental disorder. A similar, but less controversial, example is how left-handed kids were once discouraged from using their left hands and told "that's the wrong way". Left-handedness is now accepted as a normal variation in human behaviour. In both cases, trying to change the individuals did harm to them. Naturally left-handed kids were able to learn to be right-handed, but were never as good at it as they were with their left hands, just as homosexuals could be made to pretend they were heterosexual, but never seemed to fit that mold very well. StuRat 21:26, 22 December 2005 (UTC)
- There are a very small number of psychiatrists who consider it treatable if someone wants to be treated, and you can find a few reports in the English clinical literature even in the last decade. As you can tell from the above posts, this has gradually changed from a widely held opinion to a very minority opinion in North America and Europe over the last 40 years. The decision of the APA to declare it "no longer a disease" reflects the primarily social and political bases of a number of psychiatric diagnoses that have strictly behavioral definitions. alteripse 22:11, 22 December 2005 (UTC)
Electrons and their spin
I recently read a book on the history of electicity. In the explanation of electons, they are described as spinning about the nucleus of the atom. So my question is: why aren't electons stationary about the nucleus of the atom? What gives them the forward momentum to zoom arond the nucleus?
- They are not zooming around, they form a standing wave or probability field, called an Electron cloud. Dominick (TALK) 00:12, 23 December 2005 (UTC)
- They do have orbital angular momentum though. Theresa Knott | Taste the Korn 00:16, 23 December 2005 (UTC)
- Indeed they do, part of the "new age" zen of QM. Its a particle that tastes like a wave! Dominick (TALK) 00:17, 23 December 2005 (UTC)
- Eletrons have spin. This spin ultimately arises from group theory - remember, that "spinning electrons" should not be taken so literally -- it only describes a particular aspect of an electron, and at best, only a particular mathematical description of it. --HappyCamper 01:18, 23 December 2005 (UTC)
Why is wool itchy?
I have a wool, polypropelene blend Navy watchcap. It's warm, but it itches like a bitch. Why is this so? I've heard it's some kind of allergic reaction. Jasongetsdown 20:58, 22 December 2005 (UTC)
- There are two ways a material could cause a skin reaction:
- A physical irritant. A material can have sharp or rough features which abrade or puncture the skin. Fiberglass is an example of this type of irritant.
- A chemical irritant. A chemical present in the wool, such as lanolin, could react with the skin to cause an allergic reaction.
- I don't know the specifics with wool, so will let someone else answer that. One suggestion, don't wear wool directly against the skin, to avoid the reaction. For example, if you have a wool sweater, make sure you wear a shirt with long sleeves and collar which you can fold back over the edges of the sweater to keep it from rubbing on your skin. Alternative man-made fibers are also available which are just as warm and hypo-allergenic, so you might consider those. Wool also has many other negative qualities, like it's expense, the need to dry clean it to avoid shrinkage, it's tendency to absorb water and mildew after rain, and it's attraction to moths. Warm synthetics exist with none of these problems. StuRat 21:21, 22 December 2005 (UTC)
6th grade science project-"what age group has the best memory"
I have search the Internet for what age group has the best memory. I found one & only one web site with my exact question,but unfortunally that site was no longer available. I'm at my wits end. PLEASE can you direct me to a site that I can find this information.
- Is this what you're looking for? - User:Akamad Merry Christmas to all! 23:51, 22 December 2005 (UTC)
December 23
Unusual Euphemism
Okay. Here's my question. What is the origin of the rather graphic euphemism "purple-headed yogurt slinger"? Granted, the yogurt slinger part is pretty self explanatory, but the purple-headed...? I don't know if I've ever seen a purple penis, and I have to say I would wonder about the health of the person who had it. (This was prompted by an episode of Extras on HBO in which Kate Winslet refers to a "purple-headed womb ferret." I just thought I'd ask about the more common one, that I had at least heard.) Dlayiga 00:00, 23 December 2005 (UTC)
- Yoghurt slinger is self-explanatory?? I think it would need the right context. JackofOz 00:28, 23 December 2005 (UTC)
i'm actually not sure,because I'm not a boy, and I am a virgin, but I think that a pennis turns purple when the guy is arroused, or something...
- Then why did you feel your contribution would have any value? JackofOz 00:28, 23 December 2005 (UTC)
- That was uncalled for. I have a fair knowledge about and opinions on war, yet am not a veteran. Do you think only participants are allowed to have opinions on any particular subject ? StuRat 01:16, 23 December 2005 (UTC)
Color is a very subjective thing. To some people, the glans penis of some penises looks purplish or violet. - Nunh-huh 01:00, 23 December 2005 (UTC)
quantum mechanics
I think, out of common sense, that the people who think that QM is affected by consciousness or observation are fooling themselves, HOWEVER I have an open mind and I know one of the interpretations requires consciousness in the picture,so it might as well be true, but actually, I think that's rubbish... and I think what actually affects the outcome of these experiments are the methods used themselves, and not the scientist's consciousnes nor god's nor anything! anyway, what do you guys think?
Try reading the Heisenberg Uncertainty principle. A measurement of one quantity, alters the experiment and makes the other quantity "uncertain". Dominick (TALK) 00:10, 23 December 2005 (UTC)
thank you,I knew that, but I mean,can't that be because of the devices used? why does it have to include consciousness in the picture? i think seriously that it is new age BS and it should betaken lightly
No it is because any test introduces an element to the system. This is when I get to the quantum view. Unlike much "new age" science these can be reproduced, and is repeatable everywhere. An observer does not have to understand the measurement for it to work. Dominick (TALK) 00:15, 23 December 2005 (UTC)
soooo... you are saying that?
- Have you read Quantum mind? --JWSchmidt 00:26, 23 December 2005 (UTC)
- There is a simple resolution to all this - remember that quantum mechanics is a theory which is intended to be used for microscopic systems, not for macroscopic systems. If consciousness is in the realm of the macroscopic, then any attempt at extending quantum mechanical results to that is simply false. Well, strictly speaking, not quite - you could in principle try to describe a macroscopic system with quantum mechanics, but you would get nowhere. Other theories exist to deal with that, like statistical mechanics - a wonderful subject, but I have yet to see anyone attempt to explain consciousness with that yet! --HappyCamper 01:04, 23 December 2005 (UTC)
- One more thing: Lots of theories which try to link consciousness and quantum mechanics do so via the ever expansive wavefunction - yes, mathematically speaking, these functions extend everywhere to infinity - but remeber that they also drop off extremely rapidly, and are localized to an extremely small section of space - an attempt to manipulate a specific wavefunction at the macroscopic level, is well, essentially impossible. If we could do this, we would have massive benefits to society such as quantum computers already. --HappyCamper 01:07, 23 December 2005 (UTC)