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Aromaticity of pentalene

Is pentalene aromatic? According to aromatic hydrocarbon#PAHs, it is. Encyclopedia Britannica says it isn't. [1] Which is correct? ‣ᓛᖁ♀ᑐ 16:54, 28 August 2005 (UTC)

• Britannica, unfortunately. Pentalene is non-aromatic, as would be expected from Huckel's rule (there should be an umlaut over the U, but my current keyboard doesn't have them). This was confirmed in 1997 by the first preparation of According to Bally, T. et al. (1997). J. Am. Chem. Soc. 119: 1869–75, who first prepared pentalene, the monomer is extremely unstable! An isomer of pentalene, whose correct name I do not have for the moment but lets call it benzocyclobutene, is a moderately stable [6+2] aromatic. Physchim62 17:43, 29 August 2005 (UTC)

If you allow javascript on wikipedia.org (and the monobook skin possibly), you should see clickable entities on the bottom when editing that allow inserting a bunch of fun characters like umlauts. - Taxman ^Talk 18:21, August 29, 2005 (UTC)

• Good job catching that. That means, that if confirmed by another reliabel source (the ideal way) the pentalene article itself is horribly wrong too. Of course, Hückel's rule itself isn't perfect as it's article states. - Taxman ^Talk 18:21, August 29, 2005 (UTC)
  • No, Hückel's rule isn't perfect (which is why it's only a "rule") but it seems to work fine in this case. The pentalene article is wrong, and should be rewritten (my connection time is vrey limted at present, otherwise I'd do it myself). The external link which I added above is actually a copyvio, so only the J. Am. Chem. Soc. reference should go into the article. Physchim62 21:35, 30 August 2005 (UTC)

I wonder if some disambiguation is needed here? I've seen the dianion of pentalene marked as aromatic. --HappyCamper 03:11, 31 August 2005 (UTC)

A google search for pentalene aromatic, pulls up our information and mirrors of it first, but also a few links to pentalene as actually being anti-aromatic like cyclobutadiene. But it does also pull up [2] that notes the dianion is aromatic and [3] that refers to a postulated aromatic dication. I could't access the second, so someone else will have to check. But how important is it is the dianion is aromatic? How often will it exist as a dianion? Also, Wikipedia doesn't know what a dianion is, and while I can assume, can someone with some references available, fix that? Hint, hint. :) - Taxman ^Talk 19:35, August 31, 2005 (UTC)

I'm not so sure, but it's quite important in transition metal chemistry. Take for example this paper which explains quite nicely why the dianion is quite interesting...In particular, take a look at the diagrams. A dianion is an ion with a valence of 2^-. There's also zwitterion which is a chemical species with a net charge of 0, but has simultaneously a 1⁺ and a 1^- charge somewhere. Very common in polymer chemistry. Analogously, there's trianion, et cetera, and their analogous cationic counterparts. These terms aren't really used so much though as a far as I can tell, unless it's in a very specific research context. --HappyCamper 14:26, 3 September 2005 (UTC)

Molecular Biology Question:

• does anyone know the exact name for the Bovasial Protein Complex(BPC)? seems to have slipped my mind at the momement--172.168.17.18 17:53, 28 August 2005 (UTC)

• I belive you're thinking of the fullus shitium, also know as the foundation of modern made up things, like this word you're using in front of Protein--152.163.101.12 21:35, 30 August 2005 (UTC)

Question About a Medical Bill

One of my relatives was hospitalized for two days due to a car accident on the 6th of February, this year. Ever since she has been getting inundated with bills on a regular basis. Some of the items on a most recent bill are

Hospitalization Bill

Item #	Description	Amount	Date
1	Hospital Conslt	$600	2/6/2005
2	Hospital Visit	$300	2/7/2005
3	Hospital Discharge	$300	2/8/2005
4	Suture of Wnds 22 Cm	$1,800	2/6/2005
5	Add 5Cm/Less Rep	$450	2/6/2005

• Is there a doctor of medicine, medical attorney, or anyone knowledgeable about medical bills who can explain items 1 through 3, inclusive. Is it legal for a hospital to charge for these things?
• What is the meaning of item 5?

--anonym

Well, whoever is billing you is the only place that can tell you what these actually mean. They do seem to be coming from a doctor, not a hospital, though perhaps the hospital is billing on behalf of the physician. Whoever is sending the bills should be willing to explain them. As a guess, though: [1] hospital consultation is the fee you pay to a doctor who performed a consultation in the hospital - usually a specialist of some kind. [2] hospital visit is a fee you pay to the doctor who provided routine care in the hospital. [3] hospital discharge is the fee the doctor charges for discharging someone from the hospital. These are fees you are paying the doctor, and are in addition to whatever the hospital charges per day. As for [4] & [5] it seems that they are charges for suturing two wounds ($1800 for the first one, 22 centimeters long, and $450 for the additional one, which was 5 centimeters or less). None of that sounds illegal to me (but what do I know?), as long as they are only charging you once for each service. - Nunh-huh 21:47, 28 August 2005 (UTC)

I can't help you but I don't think we can know if it's illegal or not if we don't know in which country this is. I think that this is something that could vary much from country to country. Jeltz talk 21:57, 28 August 2005 (UTC)

This bill was received from a physician in California, U.S.A. --anonym

Then it looks like it was a surgeon who was called in "on consultation" to suture two wounds (possibly in the Emergency Room), did it, did one followup visit on the day your aunt was admitted to the hospital, and discharged her from the hospital the following day. - Nunh-huh 22:17, 28 August 2005 (UTC)

• In item #5, does Rep = repeat? So does this item mean 5 centimeter or less, repeat?

--anonym

More likely "repair". - Nunh-huh 22:17, 28 August 2005 (UTC)

• Does a hospital not have its own surgeons? I think at least this particular or perhaps all hospitals assign suites to their own surgeons. Later, every time they need a surgeon, they call him. Then for every coming in and going out of the suite or office, the patient get smacked with a bill. (Also, my relative has said that she has paid a cumulative of $40,000.) Am I right about my conjecture? Does a hospital not have its own physicians and nurses? Aren't the consultation, visit, and discharge parts of a huge scam. (She was scanned scores of times, her urine was glanced at an equal number of times, etc.)

--anonym

It's not a scam, it is all in the name of providing good service and getting her healthy. That happens to be expensive, but you can't have it both ways. As for multiple tests, it is of course possible they are duplicating, but it is likely she simply needed them. Also, due to the ease of suing medical practitioners even when they do a great job, there is a certain amount of defensive medicine going on all the time which along with malpractice insurance greatly adds to everyones cost. As to the multiple bills other people have answered why, and I agree consults are very common in order to get the right person (or possibly someone at all if they are very busy) to do the needed work. What may happen is they both bill you to make sure the service gets paid for. Someone will have to wade through all the bills to make sure none of them are double paid. Keep voluminous written records annotated with dates and full names of people you talk to and make them verify what services each bill is for. I also agree with others that the hospital has full time paid staff to help people with this stuff. Make use of them and be persistent. Also be persistent in getting reimbursement from Kaiser as it may take multiple calls, threatening letters and possibly the willingness to sue in court. Hire a competent lawyer of course if need be, but it shouldn't come to that if you are persistent. - Taxman ^Talk 18:36, August 29, 2005 (UTC)

That's pretty much the way it works. The basic hospital rates don't cover physician services, which are billed for separately. - Nunh-huh 23:24, 28 August 2005 (UTC) BTW - if it was a car accident, isn't it covered by insurance? - Nunh-huh 23:29, 28 August 2005 (UTC)

• She has had health insurance, luckily. However, Kaiser Permanente has not readily paid all the bills; in some instances, Kaiser has pointed out that some of the numerous bills were duplicates. By the way, you are right, when you stated that she gets separate bills from the surgeon and the hospital.

--anonym

Many hospitals employ no doctors. Some hospitals employ all the doctors on their staff (closed staff). Some hospitals employ some doctors but also have many community physicians with privileges at the hospital. Fees from doctors employed by the hospital (excluding house staff) are included in the hospital bill; fees from office-based doctors not full-time employees of the hospital will bill separately.

Few seriously ill or injured people get in and out of the hospital without seeing more than one doctor. The consultation charge is from a physician who was advising without providing the principal care (e.g., an internist seeing a trauma surgery patient to manage his diabetes). The hospital visit is the daily care from the principal attending physician (excluding day of admission and discharge). The discharge was for the same physician's hospital visit on day of discharge; it is a higher charge because it usually takes more time and involves discharge planning. If these physician charges were on the hospital bill it means the physician was employed by the hospital. I am less familiar with surgical billing but the final charge is simply for additional suturing beyond the 22 cm; I'm not sure what "less rep" means if it was transcribed correctly.

You have no idea what you are talking about with respect to the relationship of hospital and surgeons. Why would you not expect a surgeon to charge if he/she gets called from the office to see a patient in the hospital? How do you think he/she earns a living?

Finally, why on earth haven't you asked these questions of the hospital? They pay full-time employees to answer these questions. alteripse 17:00, 29 August 2005 (UTC)

Closed-source wiki software

(It said computing questions go here, so...)

Where can I compare and shop for closed-source wiki engines? Comparison of wiki software only lists open source software, and 'wiki' is so hit upon by advertisers that neither Google nor Yahoo can provide effective results. Almafeta 00:19, 29 August 2005 (UTC)

My guess is you won't find very much of it. It's somewhat against the "wiki ethic", to quote a recent answerer. Superm401 | Talk 01:20, August 29, 2005 (UTC)

I don't think it deserves to mentioned in the same sentence, but Microsoft is pushing sharepoint as an alternative to wikis. I don't exactly know what they call it, but I'm sure IBM's Lotus Notes provides something similar. -- Rick Block (talk) 02:17, August 29, 2005 (UTC)

*sigh* Almafeta 16:08, 29 August 2005 (UTC)

then there are literally hundreds of different outfits offerng software for blogging, and interaction between different people blogs. AlMac|^(talk) 03:55, 29 August 2005 (UTC)

Can I ask what the motivation for your question is? Open source doesn't necessarily mean "unsupported", if that's your concern. --Robert Merkel 06:10, 30 August 2005 (UTC)

Just looking for wiki software that doesn't mandate supporting the political goals of the open source movement. (I guess it's worth metioning that for these purposes, BSD is not an open source license.) Almafeta 13:15, 7 September 2005 (UTC)

As I understand it, using media-wiki software in a company for internal purposes is not illegal. It is only altering the software and trying to re-sell it what is illegal. Is question really: Where can I get a wiki engine so I can embbed it into a larger project that I am planning to sell? By the way, let's say I use a mediaWiki sofware as is, without modifuing the source, but I attempt to charge for accessing the content. Is this illegal? --Threner 04:30, 1 September 2005 (UTC)

Absolutely not. However, again, it's somewhat against the "wiki ethic". Superm401 | Talk 21:04, September 4, 2005 (UTC)

What did ancient romans use for medical instruments

Our history of medicine unfortunately doesn't cover ancient Rome, and it looks like we don't have anything on instruments in particular. There's a nice looking collection of pictures of Roman instruments here. If you are interested in tracking down the roots of some of the instruments and methods, Ancient Egyptians were quite renowned for their medical experitise, particularly by Greeks, who seemed to dominate Roman medicine, so I'd bet that some of their instruments carried over. (I'm restraining myself from simply recommending reading Galen.) — Laura Scudder | Talk 06:56, 29 August 2005 (UTC)

Increasing the acceleration of an object under the influence of centripedal force

Dear Sirs,

A question to which I think I know the answer, and which is possibly very easy for you to confirm.

If you have a fixed object at the end of a rod, secured at the other end so it is like the hand of a clock, if you drop the object from position 2 on a clock face, when it reaches position 6 on the face, the mass at the non fixed end will have accelerated to x Metres per second.

If you repeat the procedure, allowing a weight to travel from the fixed point of the rod to the object at the end when it is dropped, when the object at the end reaches position 6 on the clock face, will it's acceleration be greater than the original x metres per second, due to the movement of the weight down the rod to the fixed object. If this assumption is correct, could you tell me what particular laws of physics govern the phenomenon, and could you also confirm that the figure x meters per second would be improved upon if either the mass of the additional weight, or the distance it travelled down the rod were varied. Is ther a calculation to prove this?

Many thanks,

    Bill Friend.

Assuming you're talking about a frictionless, massless rod (I seem to have misplaced mine) attached to a frictionless pivot: in the first case, the gravitational potential energy of the weight at the end of the rod, which is a function of how far it drops in a purely vertical sense, is converted to kinetic energy. In the second case, there are simply two objects to keep track of. The one not at the end of the rod doesn't drop as far, but its potential energy is also converted to kinetic energy, so the answer to your first question is yes. Potential energy is mass x gravity x height. Kinetic energy is (mass x velocity²) / 2. In your case you'll have two masses, two heights, and a single final velocity. If you can't get it from here, please talk to any high school or college physics teacher. -- Rick Block (talk) 13:27, August 29, 2005 (UTC)

science human anatopmy skeletal sysytem

WHAT BONE IN OUR BODY DOES NOT GROW.

• Why the answer to that is simple, travel to the midwest, they don't belive in biology there, so all you'll have to do in BIO class is cut out pictures oif zebras from magazine covers, and make a collage--152.163.101.12 21:33, 30 August 2005 (UTC)

Having begun as a single cell, there seems to be a good argument that all of our bones have grown. — mendel ☎ 19:29, August 29, 2005 (UTC)

• And that some (maybe all) bones eventually stop growing if the individual that owns them gets old enough. - 82.172.23.66 20:01, 29 August 2005 (UTC)

Maybe he/she means a bone that is the same size in a newborn and in an adult. Ornil 20:45, 29 August 2005 (UTC)

There are indeed a number of bones in the human body that do not grow after birth. Hint: there's six of them in every human. Proto t c 13:40, 31 August 2005 (UTC)

What occurred to me when this question was first posted were the inner ear bones. They are formed by 20 weeks and I am skeptical that no growth from first fetal formation occurs, although they may not change much from infancy to adult life, in which case this is one of those annoying, poorly worded questions where we are challenged to guess what misconception the questioner is imagining or what answer the questioner intended us to give instead of the accurate answer to the literal question, which I suspect is "none". alteripse 10:58, 1 September 2005 (UTC)

Perhaps it was written better originally, and this guy just didn't ask it quite right? --Phroziac ^(talk) 13:47, September 4, 2005 (UTC)

Native POSIX Thread Library

In research done by Edward Rice in February of 2004, NPTL was compared to the Windows Threading Library. A program written in Java created multiple threads that ran at the same time. This program was run on both Windows and Linux on a dual boot system Intel non-hyper-threading chipset. It was discovered that Windows handled threads that yielded often better than Red Hat Linux 9, but Red Hat Linux 9 handled threads that yielded less frequently better than Windows. It was concluded that this was the result of the time it takes for a thread to yield and the virtual machine to pick a new one.

Who is Edward Rice? Where is this research? If it isn't available to be read anywhere, why is it referenced in this http://en.wikipedia.org/wiki/NPTL entry.

Thanks much. Christopher Warner 64.61.118.58 17:59, 29 August 2005 (UTC)

Please ask this question at Talk:Native POSIX Thread Library. If you don't get a satisfactory response in a week or so, feel free to to delete the paragraph. -- Rick Block (talk) 01:06, August 30, 2005 (UTC)

Power plant service

How many homes and or business would a 750 megawatt power plant service?

Depends on where you are (due to variations in AC/heating usage, etc.) In the US, expect somewhere between 400 and 1000 homes per MW (hotter places usually needing more power), so about 300,000 - 750,000 houses for a 750 MW plant. Businesses, I've no idea. -- DrBob 19:33, 29 August 2005 (UTC)

Unknown Mental Disorder

I am searching for the name of a mental disorder which i am having trouble even describing. I would like to know what it is called when someone will take events that happen in the world and see it in a way that makes them despise society to the point they feel despression and regret at having lived and seen such things - or even make them feel as though they have to isolate themselves simply because they can no longer stand seeing them or hearing about them. For instance, a racist attack could trigger a spiral of depression for the sufferer who, although understanding the cruel act completely, cannot overcome or get over the incident that happened to someone they may neither know or be the same race as. A further example will be the sufferer witnessing acts such as corruption, be it a from a large corporation or the local newspaper seller who does one dodgy deal ont he side. the sufferer will see such acts and feel overwhelming emotions of despite and hatred for those who would live in such corrupt ways. these two acts, and any other kind of 'wrong' act for that matter, have an effect on the sufferer who feels more than a simple dislike for what they see and know to be wrong, because they have such high ideals of what is just and right, and how the world should be. but how the world is makes them want to remove themselves from society, because they cannot bare the thought that, to them, the world is a place that will never be perfect, or even truely good. i was just wondering what such a condition would be called.

I am not a doctor or psychiatrist, but I might describe such a condition as a combination of post-traumatic stress disorder with uncontrollable empathy. If someone had this condition, though, I would strongly recommend they visit a psychiatrist. Superm401 | Talk 20:01, August 29, 2005 (UTC)

It is not a mental disorder. No specific trauma is mentioned and this is not a recognized aspect of PTSD or any other entity in the DSM-IV-R. We could trivialize it by pointing out how adolescent the combination of naive idealism and excessively harsh judgementalism is. Or we could call it a spiritual disorder. In Christian times and cultures this was termed the recognition of the fallen nature of man, or in the last century as being a soul too delicate for coarse flesh. I also suspect it comes not from an excess of empathy but an unbalanced empathy that cannot recognize the transgressors as being as equally human as the victims. If one cannot stand to live in the real world as it is among sinners, one solution often resorted to in the past is monastic life or simply the isolation of a hermit. With the right public relations support you can become a saint. Or maybe the solution is to become more familiar with the world, more accepting of human nature, and grow up... alteripse 21:18, 29 August 2005 (UTC)

You're probably right. I didn't mean it was precisely PTSD. That was an approximation. Superm401 | Talk 22:15, August 29, 2005 (UTC)

It is of course not a medical term, but the description fits Weltschmerz. (Try pronouncing that if you're Anglo-Saxon.) 82.210.117.215 18:09, 30 August 2005 (UTC)

Excellent! Veltshmairts it is! alteripse 01:20, 31 August 2005 (UTC)

This may be off-topic but the statement, If one cannot stand to live in the real world as it is among sinners, one solution often resorted to in the past is monastic life or simply the isolation of a hermit may not necessarily be completely true. Those who have chosen the monastic/contemplative way of life may not necessarily be "escaping" from the difficult-to-take experiences of the world but primarily aiming at finding a deeper spiritual connection in greater solitude. --Dpr 06:55, 5 September 2005 (UTC)

Line crossing algorithm

Ok, suppose I have a set of pairs of coordinate points representing line segments. What would be the best way to check of any lines cross?--Fangz 22:45, 29 August 2005 (UTC)

A start might be generating equations from the lines and solving the system of each pair. I.E. for a simplified example of only two lines below:

1.(3,5) and (6,11) 2.(5,4) and (7,12)

1.y=2x-1 2.y=4x-16 0=-2x+15 2x=15 x=7.5

They intersect where x=7.5. This is inefficient, but it's an okay idea to start with. Do you get the idea? Superm401 | Talk 23:13, August 29, 2005 (UTC)

• Another similar idea:

First compute the bounding-boxes of each pair of lines. They must overlap if the lines cross (necessary, but not sufficient).

For line segments AB & CD, solve the equations (by separating the x & y components) for s:

$\mathbf {A} +s(\mathbf {B} -\mathbf {A} )=\mathbf {C} +t(\mathbf {D} -\mathbf {C} )$

Bear in mind there may be no solution (lines parallel).

Now compute t from s. If the line segments cross, both s and t must be in the range 0-1. -- DrBob 23:24, 29 August 2005 (UTC)

If you really want the best algorithm for doing this, here's a paper in the Journal of the ACM which contains an optimally-fast algorithm for doing this computation. I haven't read the full paper so I'm not sure how straightforward it is to implement. --Robert Merkel 05:57, 30 August 2005 (UTC)

Understanding Quantum Spin

I am researching the standard model of particle physics and quantum mechanics, in order to get a solid conceptual grasp on the ideas therein. One topic remains quite hard for me to visualize, however: what exactly is quantum spin? I have no formal physics background, but these things interest me _very_ much. Can anyone provide an accurate metaphorical explanation of what quantum spin is?

Thanks in advance, Robert Winslow

• Have you read Spin (physics) (quite scientificly phrased)? Are there any other parts of quantum mechanics you already understand? - 131.211.210.12 08:32, 30 August 2005 (UTC)

• I have a degree in physics and have never really been able to visualise spin either, so don't think your lack of formal physics background is what is holding you back! I tend to think of it as just another quantum number. But this is a cop out. You certainly can't think of it as analogous to a classical spinning particle. Electrons have spin but they are point like particles, and how can a point spin? The spin of an electron does however create a magnetic field ( a magnetic dipole) in the same way that a spinnig ball of charge would create a magnetic dipole, so something is going on. Like I said - I don't really understand. Theresa Knott (a tenth stroke) 22:40, 30 August 2005 (UTC)

• I could be entirely wrong here, but I think I once heard it explained as: imagine having a playing card, an ace of spades, turn it around so the back faces you, turn it around again, now a queen of hearts faces you, turn around again, to have the back face you agian, and turn around another time, to have the ace of spades face you again. That's spin 1/2. (But agian, it could be that I'm talking about something entirely different.) --R.Koot 19:33, 31 August 2005 (UTC)

• Even more confusingly, even though QM spin isn't the same thing as classical spin, things like spin-orbit coupling still happen. Add in the link between spin and statistical mechanics (spin-statistics theorem), and you've got one of the most mysterious bits of QM, which I'm glad I no longer have to think about. -- DrBob 20:34, 31 August 2005 (UTC)

Do partially broken human teeth grow?

If an adult human breaks a part of his/her tooth, does the tooth grow or always remains partially broken? If the tooth is pulled out, does a new tooth grow in adults? --anon

As someone who has spent entirely too much money in lifetime paying Dentist bills, and now 100% false teeth, it seems to me the battle was to save what was left of eroded teeth until I was willing to part with the last of them. In children there is something called wisdom teeth, in which something grows, comes out, then is replaced with another, but in my adult experience, once you got a damaged tooth, or a cavety, the dentist can patch it up, but there is no "natural" cure. AlMac|^(talk) 07:18, 30 August 2005 (UTC)

I'm not sure what you mean about the wisdom teeth? --Phroziac ^(talk) 16:58, September 3, 2005 (UTC)

• Children will exchange their milk teeth, but after that your teeth won't grow anymore. I speak from experience as two people in my family had broken front teeth. The dentist patched it up with fake teeth or fake partial teeth, but once damaged, adult teeth can not recover. In fact, once you've exchanged your teeth as a kid, your new teeth won't grow anymore. They're already adult size. - Mgm|^(talk) 08:37, August 30, 2005 (UTC)
• Humans only get two sets of teeth - their milk teeth and the adult set, though the wisdom teeth at the back may not appear until you're in your twenties and (in my case) have to come out straight away. If you damage your adult teeth, that's it, you're stuck weith them - they don't grow any more. -- Arwel 12:24, 31 August 2005 (UTC)
• Which I can, unfortunatly, confirm from my own exprerience. A small piece of my lateral incisor broke of after I fell flat on my face. More than a decade later it still hasn't grown back, although it has become smoother. --R.Koot 13:10, 31 August 2005 (UTC)

• By the way, why are they called milk teeth? --Phroziac ^(talk) 16:58, September 3, 2005 (UTC)

mathematics

who discovered rational numbers?

The ancient Egyptians knew quite a lot about them, though the general idea may have crossed somebody else's mind before that. David Sneek 07:21, 30 August 2005 (UTC)

See rational numbers. --R.Koot 11:45, 30 August 2005 (UTC)

KazaaLite

My sister's computer is becoming a real pain. While it worked before, suddenly items she tries to download won't show in the traffic screen after clicking download. According to the program she's connected (searches work fine and there's a disconnected option to click in the menu) so what's going on? - Mgm|^(talk) 08:40, August 30, 2005 (UTC)

Are other people able to download files from your sister while she's connected to the network? It might be that her ISP is blocking the Kazaa service on their end, especially if she's on a college campus or something similar. Garrett Albright 16:33, 30 August 2005 (UTC)

• Haven't been able to check, because I don't know how to make sure someone gets on the same network. Anyway, I doubt our ISP is blocking the service, because she used the same ISP the day before when it worked fine and it's at home, not a campus of any kind. - Mgm|^(talk) 21:21, August 30, 2005 (UTC)

Have you installed any new software, a firewall perhaps? If all else fails and you're sure that your internet connection is working fine, you may want to try reinstalling it. If you do this, be careful that it doesn't delete all of your shared files during the reinstallation process.

Medical Information

What do doctors add in the medicine that contains antibodies in a syringe?

I might have misunderstood your question... but if you mean excipients (agents that are added to improve stability of the active ingredient or to maintain it in solution) then you can find quite a lot of information on the electronic Medicines compendium if you know the name of the vaccine. The website is http://emc.medicines.org.uk and once you've typed in the name of the vaccine, choose the link with the letters SPC (which stand for Summary of Product Characteristics) next to it, and browse the excipients section (I think it is always section 6.1). This works for UK medicines, I don't know what other databases there are, but Google might have the answer. Hope that helps, Jo Brodie, 16:49 BST, August 30, 2005.

This is a peculiar question and I suspect represents a misunderstanding or a non-Western practice. It is extremely rare for American or western European doctors to give injections of antibodies in a syringe. Antibodies in the form of gamma globulin are given by iv infusion for many problems but this doesn't involve a syringe. I cannot off the top of my head think of any examples except old fashioned passive immunity treatments for rabies, tetanus, and snakebite antivenin. There are a number of newer monoclonal antibodies used as treatments for specific uncommon conditions, but most of these are still experimental research protocols and most are given by infusion rather than injection. There were some quack cancer treatments involving injections in the past which claimed to induce a patient to make antibodies against the tumor, but these were pretty uncommon. Can you give us more context? What disease is being treated, and in what country, and is the doctor a mainstream MD or alternative practitioner? alteripse 16:19, 30 August 2005 (UTC)

The questioner really needs to give us more to go on. Another possibility is that they are referring to the use of radiolabelled antibodies in nuclear medicine. - Nunh-huh 20:41, 30 August 2005 (UTC)

Assuming the antibodies is a mistake, and concentrating on the "What doctors add" bit: I believe one thing added to (all?) injections of medicine is a buffer, to prevent blood pH from changing. -- DrBob 20:49, 30 August 2005 (UTC)

To the extent that any diluent is a buffer, it's so to avoid discomfort from the injection of highly basic or acidic solutions, which are locally irritating. It's a rare injection that would change blood pH....50 cc of sodium bicarbonate, usually in multiples, gets the job done for a while, but not your everyday run-of-the-mill injection. - Nunh-huh 22:45, 30 August 2005 (UTC) Absolutely right. alteripse 01:17, 31 August 2005 (UTC)

Huh, I guess my A-level chemistry lied to me, then. -- DrBob 03:17, 31 August 2005 (UTC) Disillusionment can be tough. Sorry if it was your first time. alteripse 10:47, 31 August 2005 (UTC)

universe as animation frames

In The Dilbert Future, author Scott Adams says, "Some physicists theorize that reality is like frames of an animated movie, with infinite universes existing at once." Any idea which physicists they are or what their theory is called. Multiverse article didn't help me. Jay 18:42, 30 August 2005 (UTC)

Probably not the physicist he was refering to, but if you're looking for that type of metaphore, I suggest you try Michio Kaku, he's pretty good for a pop culture physicist--152.163.101.12 21:28, 30 August 2005 (UTC)

Ring around the Earth

One thing which I've always wondered. If you were to build a steel ring with a diameter of, say, 100 metres or 1 kilometre greater than that of the Earth, and somehow place it around the entire Earth, would it more or less hover in mid-air with no support of any kind? — JIP | Talk 19:50, 30 August 2005 (UTC)

Someone's been reading a bit too much Arthur C Clarke, personally i thought 3001 was a bit of a let down, but I guess you liked it well enough--152.163.101.12 21:25, 30 August 2005 (UTC)

Not really. The Earth is pretty rough at that scale - you have mountains, seas, that sort of thing - which are very inhomogenous; it'd be like dealing with a lot of weird mascons. (Consider the gravitational effects of "ring next to a mountain" vs. "ring over central Pacific). It'd probably "crash to the ground" somewhere along the length - or, indeed, buckle under its own weight and do so all over the place. Shimgray 19:55, 30 August 2005 (UTC)

It wouldn't be very stable unless you spun it, but you could make it a geosynchronous orbit. You might want to look at Ringworld and Dyson sphere. Bovlb 19:59:37, 2005-08-30 (UTC)

At geosynch you might manage stable, but not at a kilometer high - local mass differences are just too significant, then. Shimgray 20:33, 30 August 2005 (UTC)

You might also find an interest in the space elevator concept. How is that supposed to stay where it is supposed to be? AlMac|^(talk) 06:08, 31 August 2005 (UTC)

The plan for that is to be above geosynchronous orbit (much much more than 1 km above the surface). Technically it would work at geosynchronous orbit, but the designers want the elevator structure to be under some tension. The ring structure would "hover" at geosynchronous orbit, except that our geoid isn't perfect and we've dumped lots of satellites up there, so I don't think it'd be particularly stable, but — as mentioned above — spinning it up would help. — Laura Scudder | Talk 15:49, 31 August 2005 (UTC)

I believe the general concept is to counterweight an elevator so that the center of gravity is at the geosynch point. As Laurascudder noted, though, we'd also have to do some major orbital cleanup. IIRC, Kim Stanley Robinson discusses a lot of this in his book Red Mars — Lomn | Talk / RfC 15:54:06, 2005-08-31 (UTC)

"Luminous toxin"

Just curious, but is "luminous toxin" (the poison that slowly killed the character in the 1950 movie D.O.A.) a real poison? According to the movie, the poison is real (from the movie: "``The medical facts in this motion picture are authentic. Luminous toxin is a descriptive term for an actual poison.'' — Technical Adviser, Edward F. Dunne, M.D.") However, after I have searched the web and Wikipedia for "luminous toxin" and only found references to it in articles related to the film (no scientific/medical articles), I am starting to wonder whether "luminous toxin" is real or not. Thanks. 61.94.149.174 06:33, 31 August 2005 (UTC)

A "descriptive term for an actual poison" means thay are describing the toxin rather than giving you it's name. Medical articles will refer to it by it's actual name. I could describe milk as "a white liquid complete baby food" but everyone else will still call it milk. Theresa Knott (a tenth stroke) 19:30, 31 August 2005 (UTC)

Probability: The “Oldest Son or Daughter Phenomenon”

Explain why in a group of 35 children at a school, a randomly selected individual has a high probability of being the oldest son or daughter in his or her family.

--anonym

Maybe because there are a lot of one / two child famillies nowadays? --βjweþþ (talk) 07:54, 31 August 2005 (UTC)

Presumably this is a math assignment. If the average number of children per family are less than 2 (as is true in most of the western world), any randomly chosen child is more likely to be an eldest than a non-eldest.

Average children per family (CperF) can be expressed as N1+N2+N3+N4+N5+N6...+N20 divided by the NF, where N1 is total number of eldest children, N2 is total number of second children, N3 is total number of third children, etc, and NF is the total number of families. There is a value of CperF below which more than half of any group of children are eldest (N1). Is this what you are supposed to compute? It would be somewhat above 2 because preschoolers (age under 5 years) would be selectively excluded from your classroom sample.

Unless King Herod or the Tenth Plague of Egypt has visited the community lately, there will always be more eldest children than second, more second children than third, etc (i.e., N1>N2>N3...N20), so that even in a society in which there are on average many children per family (high CperF), any randomly chosen child is more likely to be an eldest than a second, third, fourth, etc. alteripse 11:16, 31 August 2005 (UTC)

Also if the scholl is a kindergarten, the youngest son/daughter might not have been born yet. --R.Koot 12:22, 31 August 2005 (UTC)

Actually, this is not relevant. Whether a younger sibling was already born or not, it won't change the fact that the elder is the elder (even if s/he is the only child). Ornil 16:53, 31 August 2005 (UTC)

The Expected Value of a Sweepstakes Contest

A magazine clearinghouse holds a sweepstakes contest to sell subscriptions. If you return the winning number, you win $1,000,000 (USD). You have a 1-in-20-million chance of winning, but your only cost to enter the contest is a first-class stamp to mail the entry. Use the current price of a first-class stamp to calculate the expected net winnings if you enter this contest. Is it worth entering the sweepstakes?

--anonym

Yes. No. Maybe. Depends whose stamp it is. I think it's probably better to be doing your homework than entering the sweepstakes. Notinasnaid 07:58, 31 August 2005 (UTC)

• If the price of a first-class stamp is $1.29, then you can expect to lose $\approx -\$1.24$.

Power and torque output (of WRC cars)

I want to ask a question about power and torque, more specifically about rally car engines. Reportedly, Peugeot 206 WRC's 2-liter turbocharged engine generates 635 Nm of torque at 4000 rpm. if i'm not mistaken, this makes 667 hp at the same rpm. but the car's maximum power output is reported to be 300 HP at 5250 rpm (and 300 HP is the maximum legal power output in the championship). How can the engine develop such a high amount of torque considering that the power output is not that high? Isn't there an inconsistency between the figures? Am I just miscalculating or how is this possible? Thanks, --Ozkaplan

According to the article on torque, if $P$ is power in kilowatts, $T$ is torque in Newton metres, and R = rotational speed in revolutions per minute, if you manipulate the constants:

$P={\frac {T\times R\times 2\pi }{60000}}$

If you plug in T = 635 and R = 4000 into that I get approximately 266 kilowatts, which is about 357 horsepower. Considerably over the limit, still. As to how it's done, let's just say that creative interpretations of physics, mathematics, and indeed logic pertaining to rulebooks have been a stock in trade of automobile racing for a very long time. In the 1980's, the maximum level of turbo boost in Formula One was supposed to be restricted by the use of a standard popoff valve, which opens up to bleed off pressurised air if the pressure gets too high. Teams apparently got around this by fitting huge turbos to their qualifying motors which pumped so much air the popoff valve couldn't get rid of it all...--Robert Merkel 12:18, 31 August 2005 (UTC)

computers

what's the speed of processor for a computer system?

Speed is measured in Hertz, or cycles per second. Modern systems run in the Gigahertz range, though one cycle does not necessarily equal one instruction. See Central processing unit and clock rate for more info. — Lomn | Talk / RfC 15:36:50, 2005-08-31 (UTC)

Analysing the performance of a computer system is a very, very complex topic, if you want to tackle it in all its glory. However, these days, for most purposes, for most people, the speed of the processor in your PC doesn't really matter - you will barely be able to tell the difference in CPU speed between the slowest and fastest x86-compatible PC Intel and AMD make. The thing that causes the most perceived delay in my use of a computer is almost always my Internet connection. --Robert Merkel 22:45, 31 August 2005 (UTC)

Review of Manufacturing topic / categories

I checked a minor manufacturing topic; it got me looking into Manufacturing as a whole. It seems to me that it is a very big topic that is fragmented and difficult to navigate. I am not sure how to start reviewing it without being a vandal! The categories lists also seem in need of review. I might start by creating a "Manufacturing overview" page similar to this temporary page. Joe1011010 19:41, 31 August 2005 (UTC)

I think you should go ahead with a rewrite if you think you can improve the article(s). BUT, in a high level topic normally we would not just say "The beginings of manufacturing is covered in the Industrial Revolution." Rather, it is better to have a condensed overview of the industrial revolution in the manufacuring article, along with an italisized statement indicating that more detail can be found in the article on the main article on the industrial revolution. Happy editing ike9898 17:22, September 6, 2005 (UTC)

biosphere

Ñ How does energy and nutrients move through the biosphere? How are these two different?

I suggest you start by reading the Biosphere article and then do you're homework yourself - believe it or not, this will help you in the long run (and, no I don't think I would have believed it when I was in school!). Thryduulf 20:50, 31 August 2005 (UTC)

Truth Drug

how do u test or what kind of test can you take to verify that you have been given a truth drug with out consent?

Well you would notice a sedative effect. Like being drunk. See Truth drug for more info Theresa Knott (a tenth stroke) 20:46, 31 August 2005 (UTC)

Also, a blood test for drugs (the kind pathologists give accident victims, for instance) taken afterward would also reveal their presence. I don't know how long the presence of the different types of potential truth drugs is detectable after their admission, and specifically the "window" between when they wear off sufficiently to give you enough self-control to voluntarily get a blood sample taken, and when they are no longer detectable. I suspect it's a matter of hours rather than days, but I'm certainly no expert in the area. --Robert Merkel 22:59, 31 August 2005 (UTC)

S-box S5 on Substition box page

First, thank you for your service.

On http://en.wikipedia.org/wiki/S-box, I believe the binary value 1010 is missing as a column heading and as an output.

I think it should be the column heading for column 11, which is currently labeled 1100.

According to http://www.tropsoft.com/strongenc/des.htm, 1010 should be in column 6 (0101), row 1 (00); column 12 (1011), row 2 (01); column 5 (0100), row 3 (10); and column 13 (1100), row 4 (11). At Wikipedia, anybody can edit, with or without an account. If you spot a logical error, go to the page in question, hit the edit this page link at the top, and go to it! For added niceness, you can then proceed to the discussion link and add a link to the source so that we've got it available for review. — Lomn | Talk / RfC 20:55:30, 2005-08-31 (UTC)

Any way to learn statastics without senseless jargon or bad english?

Most statistics books seem to be written by people who lack basic descriptive skills or have yet to have agood grasp of English writing. Here we see a statistic textbook explaining cummulative frequency, a complex name for an extremely brain-dead operation, and explains it with great complexity:

"A cummulative frequency distribution can be created from a frequency distribution by adding an additional column called "Cummulative Frequency." For each score value the cummulative frequency for that score value is the frequency up to and including the frequency for that value."

Is there any books, or other sources anyone can recommend to me that will not try to complicate this very simple subject?

Let's paraphrase:

1. Take a graph. A special graph called a "frequency distribution".
2. Let's take, say, the graph of all the edits done on the reference desk...(see below)

Total number of edits made to the Reference Desk before the page split, grouped by month.

1. Each bar represents the frequency of edits done per month.
2. Now, draw another graph, with the same horizontal axis. (I just replaced the month names with numbers here instead)
3. This time, each month's height corresponds to the total number of edits done up to that month. When you do this, you get something that looks something like this:

Total number of edits made to the Reference Desk before the page split, grouped by month.

This second graph is the "cumulative frequency distribution". Each bar represents the "total up to that date." Sometimes, it's called the "cumulative distribution function" if it's normalized. Hope this helps! --HappyCamper 03:09, 1 September 2005 (UTC)

Orthopedic Surgery

Is it a good idea to leave orthopedic hardware (9 screws and a metal plate) in the proximal humerus after the bone healed and maximum cure attained?--anon Alexander

That'd be a question for your surgeon.

I can tell you that I know someone who had screws left in his bones for more than 30 years, and the only problem was that they had to be removed when the area needed another operation. After that long they were a bit hard to get out, and the extra hoops (waiting for it to heal up a bit before the next, more involved operation) dragged the whole process out.

Another friend has told me that all the hardware in his legs has made running painful as the metal does not absorb impact as well as bone. I'm sure there are other potential problems that depend on exactly what is left in where.

Your doctor will know your situation much better than us here, so ask him to go over the pros and cons with you. — Laura Scudder | Talk 04:26, 1 September 2005 (UTC)

From our personal experience, the hardware of which you speak (titanium) and in the same location of your concern has had no adverse effects after five plus years. In fact, removal would present an unnecessary risk. I'm speaking to adult and not pediatric bone growth concerns. The only side effect for Heidi seems to be at airport security. ;-) hydnjo talk 21:05, 2 September 2005 (UTC)

Slug fest!

I live in Bend OR. I recently witnessed 2 slugs doing their duty, ( I think!) But all I could see coming out of the aftermath were more slugs.I saw protruding tentacles, slime, ect., but no egg sack. It looked like live birth. They wrapped around each other, explored, ( as good sex should be), but then there was another slug...and another. It was beautiful, but disturbing. Did we witness hatching, or what????Do they come back to the scene of the crime? It was an intimate moment, and it looked tender ( who thought slugs could be tender), But what the >!@?":.....

The slug article does have a section on their reproduction (Slug#Reproduction_and_life_cycle), and it does say that they wrap around each other like you describe. However they apparently lay eggs in the ground, and don't have live births. Thryduulf 09:00, 1 September 2005 (UTC)

A question of Gravity

Hi there-- recently I have been finding out about gravity and a question keeps itching me. If you were to drain half of the magma from the earths core would the remaining liquid rearrange itself into a perfect sphere centred around the point at which gravity for this planet is generated?

In case that was slightly confusing what i mean to ask is that gravity is a single point in the exact centre of our planet so if there was just an open void around that point and something was placed on that point would it just float exactly still as forces are acting equally uopn it in every directon?

The gravity of our planet is "generated" in each and every part of it. When you add up all these minute gravitation pulls you get what we experience as gravity.

Assuming no other objects exist apart from the earth, and the earth was made hollow (and it didn't crumble), and the earth was a perfect sphere, inside the earth there would be no gravitational field or pull. As you get closer to one side of the sphere you get closer to the particles and therefore their pull on you will be stronger, but there'll be less particles in that direction of you. This evens eachother out. As far as I know, the first person to come up with this was Isaac Newton in his Principia.

So, to answer your question, the magma would do whatever it damn well pleased, i.e. there would be no gravitational force working on it, though there could be other forces. --fvw* 10:51, September 1, 2005 (UTC)

See also Hollow Earth. Thryduulf 11:02, 1 September 2005 (UTC)

Thanks for the answer but it leads me to another question. If every part of the earth produces a gravitational pull and these minute pulls combine to form what appears to be one force known as gravity why is it that we are not pulled slightly towards huge clusters of particles like say a mountian and also why is it that all of these forces seem to pull towards one point in the centre of the earth?

We are pulled slightly towards mountains, but AIUI the force is so weak that it is only measurable by scientific instruments. It takes the mass of something on the scale of a planetary body to produce a force strong enough for us to feel, and this is why we appear to be pulled towards one central point. Thryduulf 15:26, 1 September 2005 (UTC)

(edit conflict with Thryduulf) In fact, they don't pull you exactly towards the center of the Earth. Measuring local deviations in gravity is a huge part of geophysics and is a way to get information about the density of material under the surface. See gravity anomaly and geoid. — Laura Scudder | Talk 15:33, 1 September 2005 (UTC)

Oh and your comment about getting closer to one side of the sphere and the force growing stronger but the lack of particles meaning they even each other out. What is that supposed to mean? These particles that are fewer as you move closer to one side, are they supposed to be air particles because thats the only thing i can imagine moving through as easily as you say. And even each other out!!?? If the forces evened each other out wouldn't you be stuck in your position unable to move unless you can produce a force strong enough to move in a direction?

Basically, if you are to be pulled downwards by gravity, then the particles exerting the gravity need to be below you. When you are in the centre of the hollow sphere there is more of the sphere below you than there are when you are closer to the edge (as there is more of the sphere beside and above you). If all the forces evened each other out you would be stuck as you describe, however the force required to overcome them wouldn't be difficult - for example, consider how easy it is to move under the force of gravity from a body the size of planet earth. Thryduulf 15:26, 1 September 2005 (UTC)

What he was saying is that you're closer to a small amount of the Earth's rock, but farther away from a large portion of the Earth's rock. So less rock is pulling on you in one direction (but there's a stronger pull per bit of rock because you're closer), while more rock is pulling on you in the other (but there's a weaker pull per bit of rock because you're farther away) and they end up cancelling eachother out. This accounts for why you don't feel any net gravitational force inside a hollow sphere. A mathematical way of proving this uses Gauss's law. — Laura Scudder | Talk 15:33, 1 September 2005 (UTC)

One more thing, if 'particles' of whatever it is are responsible for gravity then is a black hole just an unspeakable number of them clustered together?

See teh Gravity and Black hole articles. A better answer is beyond my understanding! Thryduulf 15:26, 1 September 2005 (UTC)

Yes. A black hole is what you get when so much matter is in one place that it all collapses under its own weight, into a singularity - a point so small it cannot be measured. The gravitational attraction of this is, as you'd expect, pretty big, since it requires a lot of matter - the absolute minimum mass to form a black hole is given by the Chandrasekhar limit, which is about one and a half times the mass of the sun. Shimgray 16:06, 1 September 2005 (UTC)

Thanks guys

Deep yellow sky

The view in question.

Hello, everyone. I am writing to ask about something that I saw last night. After a rather grand storm, in which all light faded, suddenly not only the sky above, but all the space outside, became a disorientating, deep chemical yellow (see the picture to the right). Walking outside was like walking into yellowness. After about twenty minutes, during which time the yellow became darker, the light shut out, and we were in total darkness. I have never before witnessed such a thing. Do you know what this occurance is called, and what causes it? I would appreciate any help. IINAG 13:08, 1 September 2005 (UTC)

Well, in Texas we just say it means there's going to be a tornado with the storm, but I have of course no scientific backing for that and it doesn't help with the why. — Laura Scudder | Talk 15:38, 1 September 2005 (UTC)

Hello, Laura; thank you for your response. I had never knew before about there being a yellow sky with a tornado. The only thing is that I live right in the middle of England, in an area not noted for tornados (however, there was a small tornado in a nearby city, Birmingham, although this was a freak incident.) That has me wondering whether the same reason(s) that make(s) the sky yellow before a tornado acted when the air yellowed yesterday. IINAG 16:56, 1 September 2005 (UTC)

I'm trying to think of a plausible explaination for the yellow. It may be due to the storm kicking up an unusual amount of dust, and it being illuminated indirectly, by light that had already been depleted of blue by Rayleigh scattering. -- DrBob 17:37, 1 September 2005 (UTC)

It must be associated with some change in weather. I lived in Kansas for thirteen years and once in a long while something like you described would happen. The sky would rapidly adopt a very strange yellowish color. Often it was also strangely warm, and as Laura mentioned a decent indicator of an approaching tornado.

Just to clarify: yellow sky -> tornado, but tornado !-> yellow sky. In other words, as the former Kansas resident says, this is rarer than tornados so it must be related to a rather particular set of storm conditions. I found this article, which tries to explain it. — Laura Scudder | Talk 14:57, 2 September 2005 (UTC)

Thank you all for all of your help; that article is quite useful. The thing that confused me was that, ostensibly, there was no change between the weather before the yellowing and after it. Before it, it was dark, and it was raining heavily; after it, it was dark, and was raining heavily. IINAG 00:56, 3 September 2005 (UTC)

I'd like to point out that I live in Michigan, and saw this once. It wasn't quite as yellow as the picture you showed though! It was a bad storm, but I have seen worse. We did not have a tornado, but I have heard of that before. --Phroziac ^(talk) 17:12, September 3, 2005 (UTC)

Using an Ext2 NBD image under Windows

I occasionally play a little with Linux on my GameCube. For that, I have a 1GB harddrive image for use with a Network Block Device server.

However, I occasionally wish to manipulate this image without having to boot the Cube into Linux - injecting files, etc. Does anyone know if there are any tools that will let me do this? It doesn't matter if the image is mountable as a drive, or if I need to use a seperate program that mounts the image internally. --Pidgeot (t) (c) (e) 13:35, 1 September 2005 (UTC)

Search for "ext2 windows" on google. The second links looks good, but I'm sure there are several other programs if you don;t like that one. --R.Koot 15:31, 1 September 2005 (UTC)

Actually, I already have the program at the second link installed, but it only works with physical harddisks - however, Explore2Fs, the first link, did the trick - for some reason, I never thought of the image as a regular ext2 disk. >_<

So thanks for the wake-up call, I needed it ^_^;;; --Pidgeot (t) (c) (e) 15:44, 1 September 2005 (UTC)

Word to PDF

Is there any simple (free) way of transforming a word document to a pdf? I tried converting to OpenOffice, but their pdf converter makes the document ugly. Why doesn't Word have its own converter?

Thanks! --Alice

Adobe sells a PDF plugin for Word - it's not bad. The problem is that it's expensive - PDF is a proprietary file format, unlike (say) HTML, so Adobe take what the market will bear. There are a variety of free converters out there, though - do a search on doc to pdf or word to pdf - but they'll take some fiddling to work.

Also, it's quite possible the flaw lies with Word and not OpenOffice; Word uses a lot of odd proprietary formatting tricks, and often doesn't convert very well to other formats. So you may be unable to transfer some of the formatting regardless. It may be simpler to save to an RTF file, then open that through OpenOffice. Shimgray 16:02, 1 September 2005 (UTC)

It wouldn't surprise me if it *is* OpenOffice that's to blame - in my experience, it's very bad at PDFs, even with documents never opened in Word.

I suggest downloading pdf995 ([4]), a printer driver. It lets you export any printable document to PDF by printing it through a special printer. You'll have to live with it popping up a "registration reminder" everytime you make a PDF with the free version, but it's really no big issue, and you can just keep on using the free version as long as you want, there are no limitations. --Pidgeot (t) (c) (e) 16:11, 1 September 2005 (UTC)

PDF actually is an open format. Have you tried OOo 1.1? If found that its PDF converted does a much better job than OOo 1.9/2.0. --R.Koot 16:25, 1 September 2005 (UTC)

• There's also a program called CutePDF, but the people who told me about that weren't all that happy about it. Still worth a try maybe. - Mgm|^(talk) 17:39, September 1, 2005 (UTC)

Hi all, thanks for your replies.

I tried Pidgeot's suggestion and it seemed to work well. However, it changes the formatting o my document. I've got a 40+ page paper, with chapter headings at the tops of pages and References at the end. There appear to be a different number of lines per page in the pdf, which makes my headings appear in varying places down the page, and the references after 1 1/2 blank pages. How can I get it so that the formatting is the same as in my word document (and yes, I'll learn latex for the next paper!).

Thanks, --Alice

Alice, one free (but somewhat inconveient) way around this is to install a postscript printer driver (you can download one for free from Adobe, IIRC), print your document to a postscript file, and use Ghostscript to convert the postscript to PDF - it comes with a utility called ps2pdf for just this purpose. Your mileage may vary...--Robert Merkel 23:26, 1 September 2005 (UTC)

If pdf995 changed the formatting of your document, it may those changes would have been there anyway. If you were printing from OOo, that could be why. Use print preview (in Word!) to make sure it isn't a formatting error somewhere in your document.

You can also try the print->PostScript->PDF solution mentioned above, but since that's basically what PDF995 already does, it might not help. --Pidgeot (t) (c) (e) 04:48, 2 September 2005 (UTC)

Speaking of pdf, I have scanned some pages of a document and saved it as a png file (resolution 800px). I want to stitch all these pages as a single pdf file. How do I do this? User:Nichalp/sg 06:34, September 2, 2005 (UTC)

There are a few solutions to this, none of them necessarily easy. If you have a full copy of Adobe Acrobat available, it woudl be pretty easy, but if you are asking on here you probably don't have one. If you are using an Mac running OSX, you could "print" them as PDFs (see below) individually and then use Automator, I think, to add them into one big file. The other option I know of involves using the PDF drivers which come with PHP to stitch them together, but this takes a fair amount of coding knowledge (I've done it with TIFs before). --Fastfission 19:28, 2 September 2005 (UTC)

No, I don't have access to a Mac :(. I use Win and have a limited knowledge in Linux. What if I embed the images in each page and use OO to 'print' the pdf's? I won't lose the formatting as it is a png afterall. User:Nichalp/sg 05:51, September 3, 2005 (UTC)

Alice: If you are working on, or have access to, an Apple Macintosh running Mac OS X, and which also has a copy of Word (perhaps your local library or uny computer lab?), it's easy: Open the file up with Word on the Mac, select "Print" from the "File" menu, then click the "Save as PDF" button. The PDF will look more or less exactly like how the document would look if you printed it from Word. Viola! Yet another reason to love the Macintosh. Garrett Albright 06:53, 2 September 2005 (UTC)

My favorite utility so far for PDF creation is PrimoPDF. It's a wrapper around GhostScript to make it act as a printer driver, and it's all open source with no registration reminders (unlike CutePDF). --David Wahler (talk) 17:52, 7 September 2005 (UTC)

Help! Homework with physical science!

What are some accurate methods you could use to determine the identity of a sample of a white solid? --anon.

your title is missleading, this isn't physical chemistry, this sounds like a general chem lab, at best--64.12.117.12 02:10, 4 September 2005 (UTC) You didn't read the title carefully, 64. Physical science is not the same as p chem. In the US, physical science is often an early secondary school subject that is a less rigorous combination of chemistry and physics for those who will not be taking them individually. Our questioner will likely never know what p chem is. alteripse 04:22, 4 September 2005 (UTC)

• Solubility in water and other solvents
• pH in solution and reactions to acid or alkali
• Microscopy to look at crystal shapes
• The sequence of procedures of qualitative analysis (organic or inorganic)
• X-ray diffraction analysis
• Mass spectrometry
• Reaction of animal trained to react to drugs or explosives
• Feed it to a guinea pig or other, even better, a disposable, non-cute and non-furry, animal
• Taste it, like Alice did
• Circumstances of how it came into your possession (location, container, amount, accompanying objects, labels, etc)
• Ask the owner or provider of the sample

alteripse 03:44, 2 September 2005 (UTC)

I'd go for taste if it wasn't for the potentially deadly results. If you disolve it in water and it the water can now transfer electricity it's a salt. If you smell cloride it's a cloride salt. You can then add other water solutable salts to test whcih to ions the salt was composed of (look in the chapter Salts in your chemistry book for the exact procedure). --R.Koot 03:55, 2 September 2005 (UTC)

Speed of Sound

Hi, I know this might not be technical enough to warrant your attention but do you happen to know the exact speed of sound in MPH, KPH and Knots? I know its around 750MPH but i need to be sure in order for my calculations to be correct. Ryan

The speed of sound is not a constant. It highly depends on the material that carries it and the temperature of that substance. --R.Koot 10:06, 2 September 2005 (UTC)

See speed of sound for some more information. --R.Koot 10:07, 2 September 2005 (UTC)

In that case can you tell me which sequence of variables they use to determine the top speed of planes ie. If a company states it's plane can go Mach 2 then which speed are they referring to as it could be anywhere between 1200mph and 1400mph?

I would bet that the Mach number is a more accurate measure of the limit as a plane's top speed will also change with conditions. — Laura Scudder | Talk 15:41, 2 September 2005 (UTC)

As stated in the Mach number article "Mach number (Ma) is defined as a ratio of speed to the speed of sound in the medium in case." It would seem that the reference speed of sound is that in which the plane is flying. hydnjo talk 19:37, 2 September 2005 (UTC)

There are a few directions you can go with this (since the speed of sound, even if you fix the medium as "air", will vary):

• speed of sound at a standardized altitude (say, sea level)
• speed of sound at a nominal cruising altitude, not necessarily standard across aircraft types
• speed of sound at the best possible, albeit extremely unlikely, conditions

From a marketing standpoint, guess which is most likely to be the case :) — Lomn | Talk / RfC 21:14:14, 2005-09-02 (UTC)

Equaling out speeds

Hi,

I recently read an article on a similar site that stated; if you were on a train travelling at 1000mph (and the ride was so smooth you couldn't notice) and you fired a bullet off the front of the train (in the exact direction it was travelling) then the bullet would be travelling at 2000mph relative to a stationary point on the ground and at 1000mph realtive to your position (moving at 1000mph). This I can believe, but it also states that if you fired a bullet under the same circumstances off the back of the train (this is all theory, I'm not taking into account aerodynamics or anthing) that the bullet would be travelling at 2000mph relative to your position on the moving train but it would be travelling at 0mph in relation to a stationary point on the ground. This suggests that the bullet would float in that air on then just fall to the ground. Is that correct because it seems very unlikely?

Yes it is true, however... The bullet would not float in the air, but immediatly start to fall to the ground. If the bullet and the train are travelling at the same speeds, but in opposite directions, it will fall on the ground, exactly were you shot it. You will be quite a distance away however, because you are traveling at such a great speed.

You can test this yourself with a heavy object. Hold object, start running, then rlease it (don't throw it) it should travel along you for a brief moment, and will not fall on the floor were you released it. Do it agian, but trhrow the object in the opposite direction of which you are running, with a bit of tuning you can make the object land at the spot were you threw it. --R.Koot 11:33, 2 September 2005 (UTC)

I completely agree with you. This can be explained on the basis of the fact that motion itself is a relatie term. It depends on the frame of reference when you percieve an object to be in motion. By frame of reference i mean your position with respect to the object in motion (like the train and the stationary point). Most of the time the apparent speed of the object can be calculated using simple addition of vectors. --StratOnLSD 11:58, September 2, 2005 (UTC)

I think the air behind this 1000 mph train would be somewhat disturbed by the passage of the train, and more than able to whip a bullet around all over the place. So the actual result wouldn't be as simple as "floating in the air". Notinasnaid 12:03, 2 September 2005 (UTC)

Thank you to R.Koot and StratOnLSD (interesting name) for those answers, and to Notinasnaid; I believe if you read my question you would understand I was disregarding any other forces, variables and factors not covered in my question and if technicality is your specialty (which it appears to be) then you shouldn't have answered a question about a train moving at 1000mph.

Also, if you do three things simultaneously: fire the bullet forwards, fire the bullet backwards (both exactly horizontally), and drop the bullet from your hand, all three bullets will hit the ground at exactly the same time.

Another interesting result (again assuming no air resistance or other complicating factors), if you shoot the bullet directly upwards from the moving train, it will come back down at precisely the same point on the train. -- DrBob 16:38, 2 September 2005 (UTC)

Which has got to make one wonder why shooting bullets up into the air is such a common form of celebration in some cultures. Has no one ever been indirectly shot by a falling bullet? hydnjo talk 19:02, 2 September 2005 (UTC)

I'd think it's happened at some point. Similar injuries occured during WW2 as a result of shrapnel from anti-aircraft barrages eventually having to fall to the ground -- since those were usually over large cities, the chance of injury was a good bit higher. — Lomn | Talk / RfC 21:10:39, 2005-09-02 (UTC)

I don't have the details to hand, but IIRC there is at least one recorded case of an aircraft being hit by its own bullets - a modern jet, on a gunnery range, fired some ammunition and then went into a shallow dive, picking up speed. By a combination of a miscalculation and some very bad luck, it accelerated underneath its own falling shells... Shimgray 03:20, 3 September 2005 (UTC)

Yes, this definitely happens. I read an article about someone dying from gunshots into the air in a wedding somewhere in the mideast. Luckily most of the cultures that do that are in more sparsely populated areas. One specific example, my Aunt's store had a bullet come down at a very steep angle through the window in the front of the store. It shattered the window and a number of glass items in displays. I can't remember how far away they estimated the bullet was from, but likely within a mile or so. The other addition to DrBob's point, is that not only does the bullet come down in the same place if fired straigh up with no wind, but even with air resistence, it comes down at essentially the same speed it left the barrel with. fast enough to kill. - Taxman ^Talk 18:22, September 3, 2005 (UTC)

I very much doubt this. The Mythbusters proved you can't be killed by a penny dropped from a building, so I doubt you can be killed by a bullet falling from the air. It will be travveling at a much slower speed than when it was shot at you, due to air friction limiting the bullet to a certain speed. --R.Koot 19:52, 3 September 2005 (UTC)

They explained it pretty well below. The deaths part, and the exact speed coming down I did not look up, but the part about my aunt's window was unequivocably confirmed by finding the bullet that did the damage, and being able to discern the path it took. - Taxman ^Talk 16:10, September 6, 2005 (UTC)

It's also, however, more aerodynamic and heavier. IIRC, the Mythbusters conclusion was that pennies lacked sufficient mass more than they lacked velocity. — Lomn | Talk / RfC 01:46:37, 2005-09-04 (UTC)

Point 1: bullets are relatively aerodynamic, but air resistance still slows them down hugely and quickly. Take a look at the data table in external ballistics - even though this bullet has a high ballistic coefficient, it sill looses one third of its initial velocity in about two thirds of a second. This is an average decelleration of about 400 m/s^2 i.e. about 40g. Point 2: the terminal velocity of a falling bullet is between 60 and 100 m/s (depends which source you look at - probably depends greatly upon type of bullet, whether it tumbles etc.). Fast, but nowhere close to its muzzle velocity. Point 3: even so, are people killed by falling bullets ? Yes, for example it happens regularly in Los Angeles, according to the sources quoted in this article. Gandalf61 11:29, September 4, 2005 (UTC)

Need power formulas associated with electrical generators

Hello!

I'm in need of power formulas associated with both delta and wye connected AC generators.

Can anyone help or provide links?

Thanks, Rick Gilbert

Presuming a balanced three-phase resistive load:

DELTA

Vdelta = Vline

Iline = √3 Idelta

Ptotal = 3 Vdelta Idelta = √3 Vline Iline

WYE

                                                                     Vwye = √3 Vline                              

Iwye = Iline

Ptotal = 3 Vwye Iwye = √3 Vline Iline

Yoke

How do they make elbow macaroni curve?

I got stumped working on the Elbow macaroni article. They make macaroni by extruding dough through a circular die with a pin blocking the center of the circle. I see a number of references that say that a "groove" in the pin causes the pasta to curve as it is extruded. How? What does this groove look like? Why doesn't it form a ridge or valley on the finished product? Bunchofgrapes 17:11, 2 September 2005 (UTC)

• I haven't found the answer yet, but I did just find an assertion that Thomas Jefferson invented a macaroni extruder!--jpgordon∇∆∇∆ 02:31, 4 September 2005 (UTC)

It has to do with relative rates of extrusion. Pasta machines work by forcing pasta dough through a die, which simplistically speaking is just a negative silhouette of the desired shape. But if more dough is forced through one part of the die than another part, the extrusion there will happen faster, and the extruded pasta will curl.

A picture will make this much clearer. Here is the front view of an elbow macaroni die:

This is about 30cm in diameter, and as you can see it extrudes 5 tubes of pasta at once. But now let's look at the back:

The ridges you see divide the total output of the pasta machine (that is, the stream of pasta dough which this die is the target of) into ten "capture regions". (There's a rather nice analogy here to watershed.) Two regions flow into each extruded macaroni tube, but significantly, one of them (the outer one) is considerably larger than the other. Therefore, the outer edge of each tube will extrude faster than the inner, and each one will therefore curl inwards.

I haven't seen one, but I presume that the die for curly-edge lasagne consists of the long straight slit you would expect, but with some extra "capture region" at each end of the slit (corresponding to each edge of the lasagne ribbon). In this case, the extra dough volume is too localized to cause a curl, but it has to go somewhere. The edges end up being "too long" for the main body of the ribbon, so the edges end up rippling to consume the extra material.

Steve Summit (talk) 04:36, 6 September 2005 (UTC)

New Orleans City Construction History

How were portions of New Orleans built below sea level? Did these areas sink? Did they drain and/or excavate after building levees? Are below-sea-level-portions of the city built on drained parts of The Mississippi River or Lake Pontchartrain?

Any information would be much appreciated.

Thank you,

Neil Higgins

The answer is complex. Start with the Wikipedia article New Orleans, Louisiana and then take a look at Hurricane Katrina, Effect of Hurricane Katrina on New Orleans and Damage to infrastructure by Hurricane Katrina. I've found a lot of historical reference within these articles that address your questions. hydnjo talk 19:47, 2 September 2005 (UTC)

A Slot Machine

A slot machine has three wheels: Each wheel has 11 positions – a bar and the digits 0, 1, 2,…, 9. When the handle is pulled, the three wheels spin independently before coming to rest. Find the probability that the wheels stop on at least one bar.

I have two answers. I think the first one is right, but I do not understand why the second one might be wrong.

P(E₁) = $1-{\frac {10^{3}}{11^{3}}}={\frac {331}{1331}}$, where I subtract the probability of getting no bar three consecutive times (10/11)³ from 1.

P(E₂)= ${\frac {1}{1}}+{\frac {1}{11^{2}}}+{\frac {1}{11^{3}}}={\frac {133}{1331}}$, where I add the probability of getting one bar, two bars, and three bars.

Can you explain this discrepancy? Why do these two answers not conform to each other?

--anonym

The second method you used, while the idea of adding up the probablity of getting one, two, and three bars will give you the correct answer, you have not done so correctly, and it is much simpler to take the probablity of getting no bars and subtract it from 1. Your first method is correct. Y0u (Y0ur talk page) (Y0ur contributions) 21:36, September 2, 2005 (UTC)

To expand on Y0u's answer. The probability of getting one bar is

${\frac {1}{11}}\times {\frac {10^{2}}{11^{2}}}\times 3={\frac {300}{11^{3}}}$

i.e. the probabliity of a bar on the 1st multiplied by a not bar on the other two multiplied by three (because the bar could be on any of the three not just the first one).

Likewise the probability of two bars is

${\frac {1^{2}}{11^{2}}}\times {\frac {10}{11}}\times 3={\frac {30}{11^{3}}}$ Theresa Knott (a tenth stroke) 22:21, 2 September 2005 (UTC)

Old

I recently saw a commercial for Old Navy where folks were picking Old Navy products from a field of some kind of gourd-like plants, handsome and erect with big leaves. Does anyone know what kind of plants those are? Attractor 00:08, 3 September 2005 (UTC)

$12 Jean plants!!!! — Ilγαηερ (Tαlκ) 01:12, 4 September 2005 (UTC)

Film synopses for the visually impaired

Does anyone publish detailed scene-by-scene film synopses that fill in plot gaps that you can't get by listening alone? Attractor 00:08, 3 September 2005 (UTC)

• Well, for the really good films, you can find complete walkthroughs at http://www.filmsite.org -- it's worth bookmarking that site in any case. --jpgordon∇∆∇∆ 01:53, 3 September 2005 (UTC)

Expectation to Open a Safe

A safe containing $1,000,000 is locked with a combination lock. You pay $1 for one guess at the six-digit combination. If you open the lock, you get to keep the million dollars. What is your expectation?

Payoff	Probability
$106	${\frac {1}{p(6,6)}}$
(-$1)	(719/720)

Thus, $E={\frac {10^{6}}{720}}-{\frac {719}{720}}\approx \$1,387.89$. Am I wrong?

--anon

$E=(10^{6}-1){\frac {1}{P(10^{6},6)}}+(-1)(1-{\frac {1}{P(10^{6},6)}})=-\$1$.

--anonym

If there are 1000000 possible combinations (assuming 6 decimal digits), then $1000000/1000000 − $1, and if you get to try again, $1000000/999999 − $1 and then $1000000/999998 − $1 the next two times. Κσυπ Cyp   06:09, 3 September 2005 (UTC)

Modeling on a Graphing Calculator

In the World Series, the top teams in the National League and the American League play a best-of-seven series; that is, they play until one team has won four games. (No tie is allowed, so this results in a maximum of seven games.) Suppose the teams are evenly matched, so that the probability that either team win a given game is${\frac {1}{2}}$.

I would like to model the World Series with a program on my graphing calculator (TI-83), where “heads” represents a win by Team A and “tails” a win by Team B. Then I want to use the program to estimate the probability that an evenly matched series will end in four, five, six, and seven games. Even though I did a little Visual Basic programming about five years ago, I am clueless.

--anonym

the TI-83 interface is probably too primitive for you to do that, but if you really want to try, you might try looking up the rnd(0,1) command, random number generator, if I remember right.. nothing like Vb really, more like QB--64.12.117.12 02:08, 4 September 2005 (UTC)

• I know that rand generates $0\leq {x}<1$. All the programming commands are in the catalog menu or the PRGM menu. The same instructions should be executable on all Texas Instruments calculators, id est, they are the same. --anonym

World Series Probability

In the World Series, the top teams in the National League and the American League play a best-of-seven series; that is, they play until one team has won four games. (No tie is allowed, so this results in a maximum of seven games.) Suppose the teams are evenly matched, so that the probability that either team win a given game is ${\frac {1}{2}}$.

What is the probability that the series will end in four games? Five games? Six games? Seven games?

--anonym

And how far with this homework have you got all by yourself? Theresa Knott (a tenth stroke) 16:32, 3 September 2005 (UTC)

• I do not know how to start. --anonym.

Does P(4 games) = ${\frac {C(4,2)}{C(7,2)}}={\frac {6}{21}}={\frac {2}{7}}?$

--anonym

Nope. For P(4 games) you need to have one of the two teams win all four games in a row. (There is no other way it can happen). Call the teams A and B. So I reckon (and I'd like people to check my reasoning please) that

$P(4\ games)={\Big \{}P(A_{1})\times P(A_{2})\times P(A_{3})\times P(A_{4}){\Big \}}+{\Big \{}P(B_{1})\times P(B_{2})\times P(B_{3})\times P(B_{4}){\Big \}}$

Where $P(A_{1})$ means the probability that side A wins game 1 and so on.

Now all these probablilities = 1/2 so that gives P(4 games) = ?

It's harder as you go to 5 games because you need A to win 4 and lose one and there are 5 different ways this can happen (do you see why?) Theresa Knott (a tenth stroke) 22:34, 3 September 2005 (UTC)

Actually, there are only 4 ways for this to happen... You don't play game 5 if you win the first 4. Similar conditions must be imposed on the 6- and 7-game scenarios. — Lomn | Talk / RfC 22:36:46, 2005-09-03 (UTC)

Oh yes you are right! Theresa Knott (a tenth stroke) 22:39, 3 September 2005 (UTC)

Technically, only the 5- and 6-game scenarios need such conditions, as P(7)=1-P(6)-P(5)-P(4). --Pidgeot (t) (c) (e) 22:42, 3 September 2005 (UTC)

True. The conditions do exist, but there's no need to run the calculations involving those conditions. — Lomn | Talk / RfC 23:04:23, 2005-09-03 (UTC)

To the anon - can you see why that's true? I have to say your teacher set a pretty difficult HW but if you study it enough you'll learn a lot. Theresa Knott (a tenth stroke) 22:45, 3 September 2005 (UTC)

• We shall consider that team A wins. We can double the probabilities for either team winning. Moreover, we will denote the wins of A win W and the losses of A with L. We also should remember that the last game must be a win to finalize the World Series.

# of Games	# of Sequences	Probability for A	Total Probability
4	WWW,W=${\frac {3!}{3!}}=1$	$\left({\frac {1}{2}}\right)^{4}={\frac {1}{16}}$	${\frac {1}{8}}$
5	LWWW,W=${\frac {4!}{3!}}=4$	$4\times \left({\frac {1}{2}}\right)^{5}={\frac {1}{8}}$	${\frac {1}{4}}$
6	LLWWW,W=${\frac {5!}{2!3!}}=10$	$10\times \left({\frac {1}{2}}\right)^{6}={\frac {5}{32}}$	${\frac {5}{16}}$
7	LLLWWW,W=${\frac {6!}{3!3!}}=20$	$20\times \left({\frac {1}{2}}\right)^{7}={\frac {5}{32}}$	${\frac {5}{16}}$

• (The total probability for each game)=2×(probability for A). Note that the sum of all the total probabilities is one. My table on the Edit page does not show, no matter what I do.

The last game MUST be a win

Number of games    No. of Sequences         Probability
---------------     ---------------        -------------
     4              WWW|W  = 1           (1/2)^4  = 1/16
     5              LWWW|W = 4        4 x (1/2)^5 = 1/8
     6             LLWWW|W = 10      10 x (1/2)^6 = 5/32
     7            LLLWWW|W = 20      20 x (1/2)^7 = 5/52

The total probabilities will be double the probabilities shown, So

Series ends after 4 games   =  1/8
   "    "         5   "     =  1/4
   "    "         6   "     =  5/16
   "    "         7   "     =  5/16
                         -------------
                      Total =  1.00   (so this checks)

--anonym

HTML equivalent of {nowiki} {/nowiki}

What is the HTML equivalent of {nowiki} {/nowiki}? --Commander Keane 10:44, September 3, 2005 (UTC)

One way to do it is using <pre>, but that gives you monospaced text (unless overridden in your CSS). I know I've seen another tag that works *exactly* like nowiki, but I'm afraid I can't find it anywhere right now - it *may* be an unofficial extension of the HTML spec, I'm not sure. --Pidgeot (t) (c) (e) 10:54, 3 September 2005 (UTC)

Unfortunately, I didn't remember correctly. The other tag is <xmp>, but that's an obsolete element that works just like <pre>. --Pidgeot (t) (c) (e) 11:24, 3 September 2005 (UTC)

Note that PRE is intended to treat whitespace literally. It does not suppress the interpretation of HTML tags and entities. There is a small set of inline elements that are permitted within PRE, although browsers seem to tolerate almost anything. See this website for more details. Bovlb 14:44:37, 2005-09-03 (UTC)

You could use &lt ; and &gt ; tags like this <html tag > Theresa Knott (a tenth stroke) 16:29, 3 September 2005 (UTC)

Keane, could you perhaps give us a little bit more explicit idea of what you're trying to do? Garrett Albright 17:20, 3 September 2005 (UTC)

I was trying to ask about the use of "&nbsp;" here, which I acheived by swapping the usualy "&" with "&amp". I've done it now, and I'll try to be more specific next time I ask a question. Thank you. --Commander Keane 17:36, September 3, 2005 (UTC)

You have to use the "&amp" trick even with nowiki, it's a real pain until you discover it... Physchim62 20:38, 4 September 2005 (UTC)

It's <![CDATA[...]]> (yes, it's very obscure, unless you are a XHTML user, where it's used all the time with <script> and <style>). Much like <nowiki>, it can be ended only by the exact sequence "]]>". --cesarb 17:56, 3 September 2005 (UTC)

And, as expected for Wikipedia, there's already an article about CDATA, with the wrong case in the title, being a stub, and with incomplete information. I'll see if I can make it better. --cesarb 18:01, 3 September 2005 (UTC)

And it's also an obvious copyvio. Brilliant. --cesarb 18:05, 3 September 2005 (UTC)

Found a better article at CDATA section and redirected there. --cesarb 18:19, 3 September 2005 (UTC)

Create a database in MySQL and import wikipedia

I have MySQL 4.1.7 for Windows XP SP2.

then I downloaded the following file from donload.wikimedia.org:

D:\Downloads3\download.wikimedia.org\wikipedia\es\20050623_cur_table.sql

How do I:

1. Create a database in MySQL;
2. Import the above 20050623_cur_table.sql file to it, so that by typing something like:

127.0.0.1/wiki/Main_Page

in the Internet Explorer, it launches the Main Page, so that I can access wikipedia off-line. Any program (PHP, maybe?), tutorial, etc. will help.

Thanks in advance. User:Mdob | Talk 19:33, 3 September 2005 (UTC)

First you need to install mediawiki. Then you probably want to check out PhpMyAdmin. It will let you control your database very easily. Just select the wikidb, and go to the sql query window to import the file (not sure where you'd want to though). Make sure you've installed the mysql extension for PHP first too, because mediawiki doesn't work with mysqli. Good luck! — Ilγαηερ (Tαlκ) 20:10, 3 September 2005 (UTC)

Due to PMA limitations, it would probably be simpler to use this process:

1. Install Apache, PHP, MySQL and MediaWiki. Make sure php_mysql.dll is enabled in php.ini.
2. Using the MySQL command-line cliient, run the MySQL commands USE db; DROP TABLE cur;, where db should be replaced with the name of the database you specified when installing MediaWiki. Close the client after this.

   I dint specified any db when "installing" MediaWiki (furthermore I didnt install proper, just uncompressed a tarball:mediawiki-1.4.9.tar.gz ("extract here" comand with WinRAR. can you help me?

   That's why you didn't specify a DB, you're not through with the installation procedure yet.

   Installing MediaWiki is done as follows:

   1. Install Apache, PHP and MySQL and configure them. You can use PhpMyAdmin as a reference web application, once it loads without any problems, you should be good to go.
   2. Extract MediaWiki to a directory - usually, you'd do this by placing the MediaWiki .tar.gz in the ServerRoot of Apache and extracting it to that directory. Rename the resulting directory to wiki.
   3. Start Apache and go to http://127.0.0.1/wiki/. Follow the instructions to install MediaWiki.

   --Pidgeot (t) (c) (e) 20:40, 4 September 2005 (UTC)

   OK. The MediaWiki stuff is pretty much done, altough the installation log says I wont have Cache nor Thumbnails. :-(. By the way, I didnt installed W A M P separetelly, but together (WAMP), that is, I installed WAMP5. Then I tried:

1. d:\wamp\mysql\bin\>mysql --user=wikiuser --password=Etaoinshrdlu wikidb < D:\Downloads3\download.wikimedia.org\wikipedia\es\20050623_cur_table.sql

1. ERROR 1044 (42000) at line 11: Access denied for user 'wikiuser'@'localhost' to database 'wikidb'

1. What is wrong? Except for the password, everythingelse was default names (wikiuser, wikidb), Oh yes, I used MyPedia for the project name and the mp_ prefix for the database.

   Oh, right, my mistake - for some reason, the client doesn't like it when you specify the password on the command-line,but I'd forgotten that. Leave out the --password bit, it should prompt you and work just fine.

   Note that since you're using a different prefix, you'll have to use

DROP TABLE mp_cur instead. You'll also need to issue a RENAME TABLE cur TO mp_cur once you're done (you can do this through PMA). --Pidgeot (t) (c) (e) 22:39, 4 September 2005 (UTC)

1. Hmmm, no. If I try with no password, then:

1. ERROR 1045 (28000): Access denied for user 'wikiuser'@'localhost' (using password: NO)

1. and if I try with no pswd and no username than, the prompt pauses for 2 seconds and spits:

1. ERROR 2006 (HY000) at line 55: MySQL server has gone away.

1. If I try this again, the same message(s) appears.

1. But thanks, nonetheway. I'll try something tomorrow (re-installing). I need your help to one more bit, tough: How (from where?) do I download the [[5]] Doom Wiki and the Homestar Runner Wiki .sql.gz files? I tried (for the first) the simplorious download.wikicities.com guess but the message 'Inexistent Wikicity' appeared, instead. Thanks in advance User:Mdob | Talk 23:12, 4 September 2005 (UTC)

   Argh, sorry! I'm not thinking straight. You need to supply the --password parameter, but you must not actually specify the password. That is, you must put mysql --username=wikiuser --password wikidb < D:\....

   As for the HRWiki, the only reason I have that backup is because I helped them with some technical problems they had. They don't have one publicly available. I don't know the Doom Wiki, but I would think the same applies there. You'd have to ask an admin there, though. --Pidgeot (t) (c) (e) 23:20, 4 September 2005 (UTC)

1. From the command-line, go to the directory where the MySQL client is found (if it's in your PATH, you can skip that). Type mysql --user=username --password=password db < D:\Downloads3\download.wikimedia.org\wikipedia\es\20050623_cur_table.sql, replacing username and password with your MySQL username and password, and db with the database you installed MediaWiki into. The new cur table should be created and imported, though it may take a while.

You might wish to do the same for other tables. If so, follow the same procedure, but skip the first action and replace cur in DROP TABLE cur with the table you're about to import.--Pidgeot (t) (c) (e) 20:34, 3 September 2005 (UTC)

Oh are you talking about the whole max 10 kb sql file limit thing? Oops... It might be a good idea to install pma nevertheless for easy management of the whole thing. — Ilγαηερ (Tαlκ) 01:06, 4 September 2005 (UTC)

Actually, I believe the limit is 2MB (still won't do when the .sql is 36MB in gzip). But yes, for any other purpose, PMA is pretty much the way to go - it's just not an option when importing a Wiki. (I should know, considering I have an older DB copy of the Homestar Runner Wiki on one of my computers - the .sql file is 1GB uncompressed!) --01:15, 4 September 2005 (UTC)

Plant identification

• Macro look of plant
  Macro look of plant
• The plant's leaves
  The plant's leaves

I'm posting this for someone who sent me this question through a mailing list. They want to know the name of this plant. You guys seem to be good at identification, so surprise me! :) - Mgm|^(talk) 20:12, September 3, 2005 (UTC)

It might be helpful if the second pic had the apical bud in focus. Guettarda 20:17, 3 September 2005 (UTC)

Possibly a fig of some sort. Exact identification may well be impossible without flowers or fruit, though. - MPF 11:04, 6 September 2005 (UTC)

Solar System

     To whom this may concern, 

I am typing this question to you hopping that i will be takin seriously. I have taken a course in collage on chemistry, and have started to take an other course in solar systems. When i sat down i took a look at a cell make up and looked at the whole solar system. if you look at them they do have a similar look to them. Now the only difference that i can make out is that the levels of electrons on the solar system does not consist of the same law.... or does it. when we look at a cell through a microscope we shed light to the whole area of the cell. Now if we where to take that light and project it on an angle or completely to it's side would the electrons cast a shadow to the other electrons and unable us to see the other electrons needed make the cell function to what our law says. Now if we think of the Solar System the sun sheds light on an angle causing a cone shaped shadow hiding the "other planets/electrons". Also as we all know all means of life needs wheather it be light, water, oxygen, other living things... Thinking of electrons what if they needed light to be at its full ability to function so the the cell was able to split? if so what if it needed that light for a certain amount of time to make it visble to the eye weather it beeing seen through a microscope looking at a cell or lookin thruogh a telescope looking out at space. With all this my question is are us humans on a cell called the solar system?

P.S. If you could kindly help me clear my mind it would be greatly appreatiated.

Thank you

sincerly yours,

David Brideau

Quick answer: no.

Longer answer: Resemblances between cells and solar systems are superficial parallels at best. Suppose we say that the sun is like a nucleus. However, a nucleus has no appreciable gravity effect on the rest of the cell. No cell components rotate regularly about the nucleus. The nucleus is not (IIRC) the energy source of the cell (mitochondria?). Conversely, the sun does not possess any sort of genetic code equivalent needed to make another solar system. As for the electron thing... it sounds like you're rambling in hopes that obscurity will be mistaken for originality. — Lomn | Talk / RfC 01:44:41, 2005-09-04 (UTC)

Longer answer:

Hi there! You have asked a very interesting question. At best I will only be able to address partially the ideas you have presented here. Thanks for sharing them!

Remember that in science, (and for that matter in many many other things) many concepts are often presented in terms of particular models. These models are at best, an approximation to the "real world". They are designed to highlight specific properties or aspects of something, while hiding others. This can be a very good thing; should all the detail of something be presented, it might be too overwhelming for one to learn it and make sense of it all at once.

Having said this, the similarities that are observed between the cell, the solar system, and the atom highly depend on the model that is used to represent these structures. One need not represent or perceive a cell as a collection of organelles for example. You could, say, treat the cell as just a blob which exchanges energy with its environment in a particular fashion. In this particular model of the cell, its structural constituents are completely absent!

Admittingly, sometimes I do think of a cell and an atom as a "mini universe" with all its complex interactions and all, but it's also necessary and important to recognize that there are limitations to how far one can generalize these similarities. Yes, it is good to recognize the interdisciplinarity and crossover of some concepts, but sometimes they should not be interpreted too literally.

What I would highly encourage you to do, is to use college as an opportunity to secure yourself with the fundamentals. Learn the concepts thoroughly. Understand them well. Acquire a solid, reliable methodology to reason with new concepts so that you can learn and grow intellectually as you pursue your education and schooling. Learn to question effectively. Learn to think abstractly. Learn to problem solve.

Of course, take all this with a big gigantic caveat in mind: these are of course, my opinions :-)

On more technical matters:

There are a number of concepts here that are being intermingled together, some are philosophical and some scientific. What exactly is an "observation"? What about transfer of energy? Where does energy for cell division come from? Try to separate the concepts into more distinct portions, so you can answer them individually. Once you have this going, I'm sure your thoughts will become clearer. It might also help you find what you would be most intersted in as you progress further along your studies. All the best! --HappyCamper 02:22, 4 September 2005 (UTC)

Furry coating on peaches

Does the furry coating on peaches serve any purpose for the fruit? --HappyCamper 01:14, 4 September 2005 (UTC)

My father always used to say that "It's only the hairs on a goosegog that stop it from being a grape." I don't suppose that helps. Bovlb 06:03:18, 2005-09-04 (UTC)

Likewise it's only the hairs on a peach that stops it being a nectarine. Theresa Knott (a tenth stroke) 17:37, 4 September 2005 (UTC)

• I guess those hairs help keeping out unwanted insects and diseases like the skin does in humans. - Mgm|^(talk) 08:38, September 4, 2005 (UTC)
• The peach is actually a mammal. --81.154.236.221 16:59, 4 September 2005 (UTC)

.

• Hmm..interesting responses! --HappyCamper 22:44, 4 September 2005 (UTC)

I don't know at all, but I like the insect idea. The hairs make it more difficult for an insect to land on the fruit (into which it might lay its eggs, for example). Physchim62 03:04, 5 September 2005 (UTC)

I always thought that a peach was just a male nectarine that hadn't shaved. Okay, I'm kind of lying. (Though peaches and nectarines are actually the same species: a recessive gene mutation in nectarines causes the loss of the fuzz.) One of the big benefits of the peach fuzz is disease resistance—particularly in humid climates where mould can be very aggressive, the fuzz keeps the mould spores from settling on the fruit's skin. TenOfAllTrades(talk) 03:29, 5 September 2005 (UTC)

Really? - I had always thought that peaches and nectarines were different species of fruit - they've always tasted significantly differently to me. Score +1 for the reference desk! :-) Okay, so it seems that the fuzz is there to keep off bugs and to keep of spores, basically, sort of like a protection mechanism for the fruit. Score +2 for the reference desk! --HappyCamper 03:52, 5 September 2005 (UTC)

Dipoles you put in your microwave

Water is a dipole molecule you will often put in your microwave, and, through dielectric heating, cooks your food. What are some other common dipoles you put in your microwave (and get significantly hotter)? --81.154.236.221 17:03, 4 September 2005 (UTC)

I'm not really sure if there are other common things that you would put in a microwave...I guess the next thing would be household cleaner which would have ammonia in it - but it sounds sort of absurd! The only time I've ever heated a solution of ammonia was when I was working with making some really nice transition metal compounds. However, that's a different story, and it was done over a hotplate in a fume hood. --HappyCamper 22:42, 4 September 2005 (UTC)

None, although it depends what you mean by "significantly". Physchim62 22:56, 4 September 2005 (UTC)

See the excellent microwave oven article, which says:

Water, fat, and sugar molecules in the food absorb energy from the microwave beam in a process called dielectric heating. ... Microwave heating is most efficient on liquid water, and much less so on fats, sugars, and frozen water. Microwave heating is sometimes incorrectly explained as resonance of water molecules, but this occurs only at much higher frequencies, in the tens of gigahertz.

It also contains the wonderful but useless fact that the microwave oven was invented by radar enegineer Percy Spencer who noticed that a chocolate bar in his pocket melted when he stood near an operating magnetron ! Gandalf61 09:20, September 5, 2005 (UTC)

Two Different Networks

Hey, everyone,

So, once again, abusing this source of Internet knowledge in lieu of a technical support service - I have a desktop and a notebook that I'd like to network together via a crossover cable (modified Ethernet cable - everyone know what I'm talking about?). The trick is, my desktop has an Ethernet cable plugged into it most times, which connects it to the Internet via my college network. In order to connect to the college network, there are all sorts of configurations I have to place on the connection. So many, in fact, that if I switch the Ethernet cable for the croosover cable to my laptop, I have to reconfigure the connection back to its original settings, which takes forever.

Here's my question: is it possible for me to set up a network between my laptop and my desktop, which ONLY comes into play when I connect them via the crossover cable? And is there any easy way to go back to the settings the desktop needs to connect to the college network? Both computers, by the way, use Windows XP.

Well, I hope at least some of the above is understandable. If any clarification is required, all you have to do is ask.

Thanks. --Brasswatchman 00:55, September 5, 2005 (UTC)

The best way IMHO would be to add another NIC to your desktop. This way not only you do not have to change the settings, but you would be able to have both connected at the same time. Another way would be to use Windows' support for multiple hardware profiles (IIRC — it's been a while since I last administrated a Windows box). --cesarb 01:04, 5 September 2005 (UTC)

If an additional NIC is not an option (lack of physical space in the desktop), you might be able to use a router to create an internal network between your desktop and laptop, whilst giving both of them full access to the outside network. If you put your desktop as a DMZ host (effectively what it is now), you could keep the laptop totally hidden from everyone else (they wouldn't be able to connect to it), and should pretty much be able to keep your current network settings on the desktop.

However, do note that this would likely require you to use a different network class than what the rest of the college network uses. For instance, if they're using a Class A (10.x.y.z), you'd have to reconfigure your machines to use a different class (such as Class C, 192.168.x.y).

If you're not concerned about other people potentially gaining access to your laptop, you could just get a hub and use that - it should more or less be plug-and-play if you go by that option. --Pidgeot (t) (c) (e) 01:18, 5 September 2005 (UTC)

I'll try figuring out the hardware profile thing first, since that doesn't seem to require money. Thanks, everyone. --Brasswatchman 21:06, September 5, 2005 (UTC)

Distinguishing colors

Consider the following table: ‣ᓛᖁ♀ᑐ 01:27, 5 September 2005 (UTC)

1. Why do the colors yellow, cyan, and magenta appear very distinct from the immediately adjacent colors?
2. Why do red, green, and blue, in comparison, appear to cover three times as much area?
3. Why do the boundaries between these colors appear diagonal (/ \/ \/ \) rather than vertical (| || || |)?
4. For people with color blindness, where do the boundaries between regions of similar color lie, and what are their shapes?

As to #1 and #2, I would think it has something to do with the fact that red, blue and green are used at full strength for making yellow, cyan and magenta.

The point at which these secondary colors are created are where two colors are at equal strength - however, as one of those two colors slowly fades away, the other one becomes more dominant. --Pidgeot (t) (c) (e) 01:40, 5 September 2005 (UTC)

Our perception of color is incredibly dependent on neighboring colors. This could account for some of 1-3. — Laura Scudder | Talk 02:10, 5 September 2005 (UTC)

As for #3, I would say that it is due to the brain using the information from rod cells instead of cone cells when distinguishing grayscale. Personally, only the yellow seems to stand out from the adjacent colours, although this is certainly subjective. There are many diffent forms of colour blindness, not that I am aware of having any of them... Physchim62 02:20, 5 September 2005 (UTC)

Interesting. Oughtn't the rod cells respond more or less the same to colors of the same intensity, producing a uniform gradient from top to bottom, though? ‣ᓛᖁ♀ᑐ 02:31, 5 September 2005 (UTC)

Oh, just in case there are creeping qualia involved, here's roughly what I see, in greyscale. ‣ᓛᖁ♀ᑐ 02:27, 5 September 2005 (UTC)

The answer to that is a big NO,! see Image:Cone-response.png. On the other hand, each of our brains "corrects" for the response of our retinal cells, and there is no way of being sure of how another person "sees" a colour except by social norms. This can be a big problem in translation between languages, for example. My hypothesis, and I admit that it is only a hypothesis, is that the visual cortex downgrades the information received by the cone cells when there is little distinction between colours, simply because that is what it is most used to doing. In effect, humans are not evolved (or intelligently designed) to look at computer monitors! Physchim62 02:57, 5 September 2005 (UTC)

Article on collimators used in X-ray

Hi,

I just wanted to point out that (as far as I know) the information given about collimators in X-ray is wrong. The article and the picture actually describe an X-ray grid. Best regards,

Pirko

Thanks for your suggestion. When you believe an article needs improvement, please feel free to change it. You can edit almost any article on Wikipedia by just following the Edit link at the top of the page. We encourage you to be bold in updating pages, because wikis like ours develop faster when everybody edits. Don't worry too much about making honest mistakes—they're likely to be found and corrected quickly. You can always preview your edits before you publish them or test them out in the sandbox. If you need additional help, check out our getting started page or ask the friendly folks at the Teahouse. — Laura Scudder | Talk 07:32, 5 September 2005 (UTC)

Corn/Maize in China

Does anyone know when corn became widespread in China as (human) food, or as a crop? A 2005 Hong Kong film (Seven Swords by Tsui Hark), apparently set in early-mid 17th century (the early Qing Dynasty), showed people eating corn/maize ears and I was wondering if this was historically accurate. Thanks. --Dpr 06:48, 5 September 2005 (UTC)

Maize seems to have arrived in China during the mid to late Ming Dynasty, with a definite and detailed record by 1560. [6] — Pekinensis 15:33, 5 September 2005 (UTC)

Thanks, Pekinensis, I'll look at the link shortly--I'm still curious as to when it became widespread as a food, and whether it would likely have been eaten in that manner (boiled/roasted on the whole cob)--though surely that manner would be very simple/easy for people in mobile or camp environments (as in the film). --Dpr 05:37, 7 September 2005 (UTC)

Plasma Balls

Does anyone know how a plasma ball works? They are glass balls with a thin stand and a sphere of crystals inside and when you turn them on purple bolts of what looks like electricity flow from the crystals to the inside of the glassball. If you place your hands on the outside of the glass ball the purple bolts meet with your fingertips and follow them around the glass until you take your hand off. Can anyone explain?

You might want to start by reading our article on them. --Pidgeot (t) (c) (e) 11:17, 5 September 2005 (UTC)

Oh now i feel kinda silly. To be honest i don't use the encyclopedia at all, I just enjoy listening to other peoples ideas about the questions I ask and sometimes it provides some entertainment in the form of arguements between intellectuals. Thanks though i think i might actually use the link provided this time

Technology Engine

What is a Technology Engine?

I can't find a relevant definition of the term. Could you perhaps fill us in as to what context this term is being used in? Garrett Albright 14:33, 5 September 2005 (UTC)

Does this describe some sort of "futurist" invention? (E.g. on the order of Buckminster Fuller--not to disparage him) --Dpr 05:40, 7 September 2005 (UTC)

There is a Technology Engine web site. The site says "This web site is under construction... with the 1and1 tools it may take years to get it right."

Fossils

if you were taking a group of children to a museum to look at fossils, why would you see more marine type fossils rather then terrestrial?

Probably because critters have been living on the ocean for a lot longer than they've been on land, and there's been more, and a greater variety, of ocean-dwellers throughout history too. See Timeline of evolution. Garrett Albright 19:51, 5 September 2005 (UTC)

Also marine animals are far more likely to get made into fossils, what with all the layers of silt etc that's constantly being liad down and turning into sedimentary rocks. Theresa Knott (a tenth stroke) 22:06, 5 September 2005 (UTC)

Cinnamon

Does cinnamon bark contain vitamin C? If it does, would any remain after harvesting and drying? ‣ᓛᖁ♀ᑐ 19:56, 5 September 2005 (UTC)

• Cinnamon does contain some vitamin C; not a lot. 2 teaspoons of ground cinnamon contains 1.28mg of vitamin C. Couldn't find details on how much is the bark before harvesting and drying. --jpgordon∇∆∇∆ 21:43, 5 September 2005 (UTC)

Okay, thanks! ‣ᓛᖁ♀ᑐ 21:58, 5 September 2005 (UTC)

Sounds like you are referring to the erroneous Culpeper scurvy reference that was deleted, restored and deleted again from Cinnamon. The reference was actually to Drimys winteri or "Captain Winter's Cinnamon" which is unrelated to true cinnamon. -- WormRunner | Talk 01:07, 6 September 2005 (UTC)

DivX and XviD

Do the DivX and XviD codecs take advantage of my computer's graphics card for encoding and decoding, or is it all done by the CPU? the wub "?/!" 20:59, 5 September 2005 (UTC)

AFAIK, the encoding/decoding is all done by the CPU. However, the final colorspace conversion when decoding can be done by the graphics card. --cesarb 21:25, 5 September 2005 (UTC)

Subatomic Radiation Shield?

Hey, everyone,

I'm a science fiction writer trying to cobble together a concept. Any scientists out there, would you tell me if there is anything extraordinarily stupid about what I'm about to suggest? - Radiation is, when you get right down to it, just a group of rogue particles created or emitted by a substance undergoing decay - either accelerated, in the case of fission, or slow, as in standard radioactive decay. So since radiation is a particle, it should be technically possible to filter out radiation on an atomic level through nanotechnology. I'm thinking of what basically looks like the quantum equivalent of the Strategic Defense Initiative - something that spits out a particle to deflect or destroy the radioactive particle. Or maybe a better idea would be a quantum-sized "filter" that lets in some particles but not others; basically acting as a net that lets larger particles through but grabs the radioactive particles. --Brasswatchman 23:15, September 6, 2005 (UTC) So, where am I wrong? Thanks. --Brasswatchman 21:14, September 5, 2005 (UTC)

How are you going to destroy the particle? You could annihilate it with it's antiparticle but the energy would still be there in the form of gamma rays. You can stop gamma rays with matter. A bloody great lump of lead should do the trick - bit that's probably too crude for you.

Some sort of net? The thing about radiation is that it is ionising Maybe your net could be transparent when neutral but turns opaque when it's ionised. Theresa Knott (a tenth stroke) 22:04, 5 September 2005 (UTC)

Well: (1) not all radiation is particulate (ie, massive particles); (2) even the "biggest" (most massive) particle radiation—the heavy cosmic rays—are only atomic nuclei, whereas nanotechnology is at the scale of cells or big molecules; (3) SDI presupposed a method to detect and track ICBMs from launch, but you have nothing analogous to that at the nuclear level; (4) even if, somehow, you managed to annihilate a cosmic ray, you now have gamma radiation carrying the combined energy of the original particle and your magic bullet; (5) it is misguided to say that particle radiation is composed of "radioactive" particles, since most of it is perfectly stable atomic nuclei or free electrons; (6) "quantum-sized" is not a definable term. I hope this helps. Sharkford 22:06, 5 September 2005 (UTC)

Just remember that sometimes sci-fi is more enjoyable (even for scientists) when it leaves how things work to the imagination rather than trying to cobble together an explanation from jargon. Can you tell me how every bit of a computer works? If not, can you tell me the end result of how a computer functions? Remember that most of your characters will have the same answer to those questions about their technology as you do about ours. — Laura Scudder | Talk 22:21, 5 September 2005 (UTC)

Responce to Theresa: right. So, as Sharkford mentioned, 'not all radiation is particulate.' So that irons out the 'magic bullet' idea, more or less. Hmm. Just glancing at the articles you linked to, trying to recall what little I can recall from AP Physics - what about the photoelectric effect? Is there any way that could be tapped to reduce gamma rays, in such a way as to reduce the overall radiation? As for the response to the 'netting' idea - so ionization would be the 'switch' that tells the netting to let particles in or out? That's a great idea. Mind if I steal that? Response to Sharkford: 1) Granted. Thank you. 2) When I said "nanotechnology," I was using it as a generic term to refer to any type of organized technology that operates on a smaller scale impercievable to humans. I apologize for my inaccuracy. 3) It's science fiction. I don't necessarily have to. 4) As Theresa said. Understood. In addition to my answer to Theresa - does the gamma radiation have any particular direction or vector? 5) All right. Once again, I apologize for my inaccuracy. I was just trying to describe my point. 6) Once again, I apologize for not getting the proper term. I'll have to be more careful in the future. Response to Laura: Yes, and an excellent point. Lord only knows that people have been accepting things like "deflector shields" for years now without batting an eye. All the same, I'm curious as to what scientific theory might say on the subject, especially as it pertains to how these kind of defenses might operate or behave. But thanks in any case. :) Thanks, everyone. Appreciate it. --Brasswatchman 01:15, September 6, 2005 (UTC)

When you're dealing with x- and gamma ray photons, there are typically three processes at work to absorb them when they enter a medium. Usually one of these processes will dominate depending on the energy of the photon in question.

1. Photoelectric effect dominates at low energies: up to around 500 keV. The photon is absorbed completely by an inner shell electron of an atom. The absorbed energy kicks the electron free, and it carries any extra energy with it as kinetic energy. The efficiency of photoelectric absorption falls off as photon energy increases.
2. Compton scattering is important at moderate energies: from 500 keV up to ~3.5 MeV. A gamma ray photon passes near an atom and transfers some energy to an outer shell electron. This ionizes the atom (again, the electron is kicked loose) and lowers the energy of the scattered photon.
3. Pair production takes place at very high energies, and dominates at photon energies above about 3.5 MeV. A photon with at least 1.02 MeV (the probability of pair production increases with energy) passes near an atomic nucleus and spontaneously converts into a particle-antiparticle pair (usually an electron and a positron).

If you throw energetic gamma rays at a lump of matter, you'll get all three processes happening—pair production and Compton scattering convert high energy photons to lower energy ones, and the photoelectric effect finishes off whatever is left. The efficiency of the photoelectric effect is highly dependent on the atomic number (Z) of the absorbing atom; the efficiency goes up as something like Z to the fourth power. Compton scattering goes as about Z.

For particulate radiations, you have negatively charged beta particles (high energy electrons) positively charged alpha particles and heavier atomic nuclei, and uncharged neutrons. There are various scattering and absorption products that take care of these guys. Note that the rapid deceleration of a charged particle will generate secondary gamma or x-radiation called bremsstrahlung. TenOfAllTrades(talk) 03:37, 6 September 2005 (UTC)

I must ask: is anyone aware of research into encasing radioactive atoms in buckyballs? This might be of interest as well...--HappyCamper 03:52, 6 September 2005 (UTC)

I remember some discussion of that possibility shortly after buckyballs were discovered; I'm not sure if anything has come of it. There the idea was to trap these nasty atoms inside a relatively chemically-inert cage to make it more difficult for them to escape from physical containment. A buckyball shell would have only a negligible effect on radiation emitted from inside, however. (It's sort of like putting a firefly in a glass jar; it makes the firefly easier to handle, but the jar doesn't keep any of the emitted radiation in.) TenOfAllTrades(talk) 04:15, 6 September 2005 (UTC)

So any method that someone uses to screen out gamma radiation that involves the three methods you mentioned is also going to produce this bremsstrahlung secondary radiation? Very interesting... I notice that the article mentions that the bremsstrahlung resulting from blocking beta particles may, paradoxically, be stronger in magnitude that the original radiation. What about for gamma radiation? What's the magnitude of the secondary radiation compared to the original radiation when dealing with that? Anyone know? As always, thank you very much for your time. --Brasswatchman 23:15, September 6, 2005 (UTC)

To be clear, you get secondary radiation from rapid deceleration of charged particles: alpha particles, beta particles, and heavy nuclei. Medical x-ray machines work by aiming an electron beam (beta particles are fast electrons, remember) at a metallic target; as the electrons are stopped by the target, secondary x-rays are generated. The intensity of secondary radiation depends heavily on the atomic number(s) of the nuclei in the target material—tungsten is typically used because it has a high atomic number (74) and because it tolerates high temperatures.

So the type of shielding used depends on the type of radiation you anticipate. Shielding against x-/gamma rays is accomplished using dense, high atomic number materials like lead. Shielding against alpha and beta particles is best done using low atomic number materials—those have poor penetrating power on their own, so you want to reduce the generation of secondary radiation as much as possible. (Phosphorus-32–a beta emitter–is regularly used in biological laboratories. Typically sheets of plexiglass are used for shielding; these contain carbon, oxygen, and hydrogen. A sample of P-32 wrapped in lead foil is actually more harmful to humans than the same sample sitting exposed on the benchtop.)

If you're expecting a mix of different types of radiation, then you have to employ a defense-in-depth strategy of layered materials—or just use a thick layer of lead or concrete. Or, if you're Larry Niven, just use a layer of Ringworld floor material. TenOfAllTrades(talk) 14:41, 7 September 2005 (UTC)

It's predicted that Bose-Einstein condensates can be contained inside carbon nanotubes. Would this be able to stop all types of radiation, if the condensate could be kept cold enough? [7] ‣ᓛᖁ♀ᑐ 15:09, 7 September 2005 (UTC)

That's an interesting way of going about it. I think. Sort of like shielding yourself with a black hole, without all the messy gravity. --Brasswatchman 19:57, September 7, 2005 (UTC)

In such an arrangement, the nanotubes ought to be kept positively charged, in order to absorb beta particles and prevent alpha particles from sticking, no? Perhaps some sort of nanotube heat pump could be worked in to allow condensate to boil away energy in a controlled manner. ‣ᓛᖁ♀ᑐ 20:30, 7 September 2005 (UTC)

That's a neat idea; I was thinking that something really dense like neutronium would do it, too—but it's a bit difficult to carry around. :D TenOfAllTrades(talk) 20:52, 7 September 2005 (UTC)

In Vivo 47th chromosome trials/studies worldwide

Please direct me to the persons/companies currently involved with this apparently promising gene vector. Viral vectors are less desirable, but am still interested, esp. for ADL/AMN.

Are you referring to this? This article describes development of an "artificial chromosome" as a vector for insertion of new genes. It names a couple of people and 2 companies involved in the research. alteripse 02:49, 6 September 2005 (UTC)

Conversion of Winamp skins

Is there a way to convert Winamp skins to Windows Media Player skins? I've tried using the wa2wmp.exe program (in the Windows Media bonus pack), which supposedly converts WSZ files, but I haven't had any luck with it. --Dynamite Eleven 03:32, 6 September 2005 (UTC)

rounding to one decimal place

whats the one decimal place of 11.35? and what the one decimal place of 11.45? 218.111.213.149 03:33, 6 September 2005 (UTC)

• Uh....11.4 and 11.5 respectively, I suppose. Is this a trick question? (I guess the answer would depend on which rounding method you use)--inks 03:39, 6 September 2005 (UTC)

• Some rounding schemes insist that you do things differently if the digit next to the 5 is even or odd...as inks said. --HappyCamper 03:50, 6 September 2005 (UTC)

• Yep, depends on the method. A (the most?) common method is round to even used to eliminate bias from always rounding 5's up. Using round to even the answers would both be 11.4. - Taxman ^Talk 15:51, September 6, 2005 (UTC)

• Related question: 11.33444444445. Rounding to 2 d.p.; would it be 11.33 or 11.34? User:Nichalp/sg 07:54, September 6, 2005 (UTC)

• • 11.33. Everything after the next digit is of no importance in the rounding schemes I've encountered up to now. If you want it rounded to x decimal places, you look at the (x+1)th and then round up or down. — File:Austria flag large.png ナイトスタリオン _ㇳ–ㇰ — 08:54, 6 September 2005 (UTC)

Chemical equation for combustion of coal

Hi, Can someone please tell me the full chemical reaction for the burning of coal? And petrol if possible? Thanks! --Fir0002 09:46, September 6, 2005 (UTC)

Coal is mostly carbon, so the basic reaction is C + O₂ –> CO₂. But incomplete combustion, and impurities in the coal (tar, sulfur, etc, etc), lead to the occurrence of thousands of other reactions, which is where all the smoke and stink come from. Petrol is mostly octane (C₈H₁₈), so the basic reaction is 2 C₈H₁₈ + 25 O₂ –> 16 CO₂ + 18 H₂O (I think that adds up!). Again, there's various minor components which produce the smells. Also the odd nitrogen molecule in the air gets caught up in the heat of the moment and burnt to nitrogen dioxide (more smells and pollution) - MPF 11:46, 6 September 2005 (UTC)

I think it is incorrect to say petrol (gasoline) is mostly octane. From that article it states that "The bulk of a typical gasoline consists of hydrocarbons with between 5 and 12 carbon atoms per molecule." and that octane rating is the term for the combustion properties of gasoline, but it doesn't necessarily mean there is any octane at all in the fuel, because other compounds can have a higher octane rating than [iso]octane. I don't know what the most common distribution of compounds in gasoline is though, and I also failed to find a more detailed distribution for diesel than is in the article. - Taxman ^Talk 18:38, September 6, 2005 (UTC)

Some of the stink of burning coal (and diesel fuel, too) comes from the combustion of sulfur compounds to produce various sulfur oxides (mostly sulfur dioxide: SO₂). Sulfur dioxide, in addition to its unpleasant odour, is also a key contributor to acid rain—sulfur dioxide combined with atmospheric water vapour (H₂O) forms sulfurous acid: H₂SO₃. Modern coal plants are equipped with scrubbers which absorb SO₂ by reaction with limestone (calcium carbonate: CaCO₃). Many jurisdictions limit the amount of sulfur permitted in diesel fuel (in most of the United States and Canada, I think the current limit is 500 ppm, and there is a push to reduce that to 50 ppm in some areas.)

Thanks everyone for your help! --Fir0002 12:15, September 7, 2005 (UTC)

Ozone depletion because of cooling of stratosphere

Why would ozone levels be depleted if the stratosphere is cooled? --Fir0002 11:04, September 6, 2005 (UTC)

The two are not related - ozone depletion is due to catalytic decomposition of the ozone by various human-released pollutants such as CFCs. - MPF 11:53, 6 September 2005 (UTC)

Because when the stratosphere cools, clouds of ice crystals can form. The surface of these crystal acts as a catalyst for some of the reactions which lead to destruction of stratospheric ozone. This is why the depletion in the ozone layer is greatest at the poles and during winter. Physchim62 21:42, 6 September 2005 (UTC)

THanks for your answers. I asked because it said here that it enhanced the ozone depletion but not why. --Fir0002 11:59, September 7, 2005 (UTC)

The night sky, as seen from Mars

Hi, I'm a long-time answerer, first-time question-asker. Poking around on the JPL Nasa site led me to wonder why I'd never seen any pictures taken of Mars' night sky as seen from the ground. What with the Viking landers/MERs and various other landers, you'd think someone would have taken a photo at night. Do these pictures exist, or is there some technical reason why it wouldn't work?

Or is it all just a fake on a soundstage? :P --Sum0 11:51, 6 September 2005 (UTC)

Judging by the Mars sunset pic Image:MarsSunset.jpg being rather under-exposed, I'd say the camera on board is not sensitive enough to get a decent night photo. Or, perhaps more to the point, they've better things to do with the limited power resources available - a night photo might not teach us a lot. - MPF 11:59, 6 September 2005 (UTC)

There are night photographs, but they're not much use; you can't see much, really. The two rovers currently landed have produced a few, out of interest as much as anything else. this page has a selection from one night session, including a starscape in Orion, a very faint image of Earth, and - of all things! - a streak which is probably the Viking 2 orbiter.

In addition, Mars landers are solar-powered, severely limiting the power budget for doing things at night, and they like to keep the instruments from doing anything much during the cold, cold nights. So that features in. Shimgray 13:13, 6 September 2005 (UTC)

Thanks for the replies, I thought it might be something like that. Incidentally, that picture of Earth is rather awe-inspiring when you consider it. --Sum0 11:24, 7 September 2005 (UTC)

Mars Global Surveyor has also imaged Earth, though this time from Mars orbit - it's even possible to discern continents! [8] Shimgray 11:40, 7 September 2005 (UTC)

Does anyone know what plant this is?

File:UnknownPlantCG1.jpg

An unidentified plant. Maybe milkweed.

File:UnknownPlantCG2.jpg

An unidentified plant. Maybe milkweed.

I was at my local zoo with my cousin and her daughters, when we came across this plant. She suspected it might be milkweed, and her comment left me very curious. I snapped this picture for reference, then cropped it a bit. Can anyone either confirm or give a different id on this plant? CanadaGirl 13:58, 6 September 2005 (UTC)

Not knowing what local is for you, and not being a botanist, I can't be sure, but I'm pretty confident you are right. The pod in the right side of the middle of the photo seems convincing to me. A shot more of the top of the plant would be easier to tell for me. Were there Monarchs nearby? - Taxman ^Talk 15:42, September 6, 2005 (UTC)

Local for me is southern Manitoba, Canada. I have added a wider shot of the same plant. I didn't notice if there were Monarchs. Thanks for your help. CanadaGirl 15:52, 6 September 2005 (UTC)

Looks like Buttonbush Cephalanthus occidentalis (Rubiaceae) to me. We don't have a page on that yet (not even on the genus Cephalanthus) - I'll write it if I may use the pic - MPF 18:15, 6 September 2005 (UTC) - Second thoughts - not convinced on Buttonbush any more - it doesn't quite match - MPF 18:30, 6 September 2005 (UTC)

Well that image doesn't seem to help any more, but milkweed still seems very plausible to me. Compare the pictures of the pods on the image in our article to those on yours. Based on those, I'd have a hard time believing it is anything different, but like I said, I'm no botanist. But if it is important, you could always take it to your local university botany/biology department and ask them. The people near that zoo exhibit should know too. I was thinking if it happened to be a monarch exhibit, milkweed would be a shoe in. Google searching for milkweed also showed that there is a lot more variation among the milkweed species than I was aware of. - Taxman ^Talk 18:24, September 6, 2005 (UTC)

Crab

Mystery crab

Moved from Wikipedia talk:WikiProject Tree of Life

It's a long shot but can anyone identify this crab, spotted on the south coast of New South Wales, Australia?--nixie 11:42, 2 September 2005 (UTC)

<insert your own joke about crabs down under, I'm tired> - Taxman ^Talk 03:42, September 7, 2005 (UTC)

Heat damage to bottled water

If I carry a bottle of water, that is still sealed, from the store, never been opened, on my bike, in Arizona, where summer temperatures can stay above 100 degrees for days, how long is that bottle of water still consumable?

Jrb

At above 100°C, the water will boil, so the bottle may explode when sufficient pressure has built up. It will also be lethal for the cyclist. - MPF 18:37, 6 September 2005 (UTC)

Arizona doesn't reach 100°C. Jrb is talking °F Theresa Knott (a tenth stroke) 20:19, 6 September 2005 (UTC)

So what does that archaic F cr@p translate to in real money, then?? MPF

The Fahrenheit article gives the formula, but it's about 38°C - Taxman ^Talk 22:36, September 6, 2005 (UTC)

I would think an unopened bottle of water from a store would remain potable pretty much indefinitely. Tap water stored in a water bottle, however, would remain potable for much less time, unless treated in some way. ‣ᓛᖁ♀ᑐ 15:35, 6 September 2005 (UTC)

Depends on your definition of consumable. At 100 degrees, the water certainly wouldn't be very refreshing. Depending on how you store the water bottle, solar heating could take it well above that. I'm assuming you are more worried about chemicals leaching from the plastic? I think all plastics used in water bottles are relatively benign, but if you look on the bottle for the specific type, and look for the heat decomposition of that type, you may find more useful information. Was there something other than that you were worried about? You may also want to look into something akin to a desert water bag [9] that uses very effective evaporative cooling. - Taxman ^Talk 15:36, September 6, 2005 (UTC)

Also effective may be freezing the water before you need it, depending on how long you'll be outside. The water will melt in the heat but remain cool while there is ice left. Note that the bottles must be emptied by at least a few inches before freezing, to prevent them from bursting. ‣ᓛᖁ♀ᑐ 17:14, 6 September 2005 (UTC)

In terms of degredation of the plastic, the two water bottles on my desk are both made of Polyethylene terephthalate (PET / PETE). The wikipedia article on PETE does mention that the plastic degrades with high temperatures, leading to the production of acetaldehyde - which is naturally occuring and, according to our article, harmless other than the possibility of hangover-like symptoms. Thryduulf 15:51, 6 September 2005 (UTC)

Additionally, "high temperatures" in this case are well over 100°F; PET decomposes around 300°C (572°F). Its melting point is somewhat lower (255°C, 491°F) — and of course the bottle would explode well before reaching this point — so at least temperature should not be a problem. [10] ‣ᓛᖁ♀ᑐ 16:16, 6 September 2005 (UTC)

If it's not decomposing, what is the cause of the plastic/chemical taste from waterbottles that have been left in the sun? - Taxman ^Talk 18:27, September 6, 2005 (UTC)

That's probably due to the quality of the manufacturing process. Some chemical residue may end up in the plastic and leach out over time; PET is fairly permeable (enough so that various pollutants could get into the water as well, if the bottle is not stored in a clean place). Some companies make water bottles designed to prevent this sort of thing, such as the Platypus brand (lined with polyethylene). [11] ‣ᓛᖁ♀ᑐ 18:40, 6 September 2005 (UTC)

inertial guidance systems

I would like to know something about the usage of inertial guidance system.Can this system be used in a car for determining its position and speed?And what will be cost of using such an instrument in a car? And if it is not feasible for economical or technical reasons,is it possible to measure the position and direction of a car over a distance of 15-30kms fairly accurately so that it can be used to know the location of a car at any moment of time in a journey.Can we use speedometer or distance meter in a car to know the distance moved by the car and can we use steering wheel movements to determine the direction of car for this purpose or some kind of a sensor which can do this thing economically? --203.197.74.148 15:34, 6 September 2005 (UTC) Sumit Malhotra s_malhotra@iitb.ac.in

Inertial systems can do the job (they'd be more accurate than the speedo/steering method); however, GPS / DGPS is a better solution, in my opinion. — Lomn | Talk / RfC 22:09, 6 September 2005 (UTC)

Yeah, unless there was some compelling reason *not* to use satellite navigation it makes little sense. A high-quality electronic compass sensor would probably cost more than a GPS, given that you can get a GPS unit with a USB interface for well under 100 USD. --Robert Merkel 23:22, 6 September 2005 (UTC)

I believe before GPS's Selective Availability was turned off (which made street-precise GPS available to the public), there were a few hybrid GPS/inertial nav. systems around. I remember hearing of a trial of one in Japan in the late 80s/early 90s. -- DrBob 23:27, 6 September 2005 (UTC)

Yeah, I remember them (and the joys of the US government playing silly buggers with GPS) too. If you're still interested in a hybrid system, marine autopilots are fitted with fluxgate compasses, and have been since before GPS existed. Some even have gyrocompasses. Marine fluxgates are not cheap (hundreds of USD); gyrocompasses are even more expensive. --Robert Merkel 08:23, 7 September 2005 (UTC)

medical doctor

Hi! Can you help me find contact information for this very famous fertility doctor: Dr. Severino Antinori, in Rome, Italy? He appears in several of your articles, but there is no contact information for him--e.g., address, email, phone. Thanks.

S. Ashe sashe@cerritos.edu 562.621-1874

• I'm sorry. Wikipedia doesn't include contact details for people. But if you know where he works, I would imagine his hospital/clinic can help you contact him. Such organizations usually have websites you can visit. - Mgm|^(talk) 10:41, September 7, 2005 (UTC)

A google search with Severino Antinori fertility yields dozens of stories about him. He has a fertility clinic (International Associated Research Centre for Human Reproduction, Italy) in Rome described as being "500 yards from the Vatican" (about 0.5 km). I found 2 links to his clinic's web page but neither seem to be currently valid. [12] and [www.raprui.it/home_i.html]. A report of his work is PMID 7782415. alteripse 10:55, 7 September 2005 (UTC)

The effect of human Bioenergy on the propagation of elastic waves

Performing research on the human body and its radiation of energy fields. Frequently called the human Aura that is linked with the Chakra System. Elastic waves define a spectrum between ultraviolet and light.

Any addition information in your encyclopedia on this subject?

Thank you,

Prof. J

You can try aura (paranormal) - and note the references at the bottom of the article; these may be useful. You might also like to try our articles on Chakra, Kirlian photography. All these articles have many useful links to other associated topics. Proto t c 10:10, 7 September 2005 (UTC)

And don't forget to submit your positive results for the James Randi million dollar prize! alteripse 11:02, 7 September 2005 (UTC)

Banana Peel?

Is Banana peel actually especially slippery?

Yes. As the outside of a banana peel (the more yellow side) is actually quite sticky (try rubbing your hand across it - there's a lot of friction there), and the whiter inside has (when still moist) a very low coefficient of friction, when you put your foot on the peel, the friction of the yellow, outer side ensures your foot will stay on the peel, while the slippery inside will ensure you slide across the floor, and usually fall over.

However, for this to happen, three things need to occur: 1) The peel must have the slippery (inside) side on the floor, and the yellow outer peel facing upwards. 2) The floor the peel is on must be hard and relatively smooth (ie, a polished or tiled floor). 3) The peel must still be moist (ie, not been there for a while.

So yes. A banana peel is especially slippery. Proto t c 13:08, 7 September 2005 (UTC)

Best Reference Desk question and answer ever. Garrett Albright 14:32, 7 September 2005 (UTC)

Katrina Effect

What is the Katrina Effect? The name applied to instances where political, military, and other officials respond very poorly and very late to a major disaster.

Did you answer your own question? Anyway, that's a neologism if I've ever heard one.

Try asking this person for more details. MPF

CHEMISTRY

how heat can turns solid matter into liquid matter in molecules reaction?

HOMEWORK QUESTION. Heat is energy. Molecules in a liquid are moving around more (have more energy) than molecules in a solid. Start with that. Garrett Albright 14:32, 7 September 2005 (UTC)

Earth air travel

Suppose two points on earth equator surface which is 180° separated. And two planes is going at the same time from A to B with same speed, one move west and one move east. Are both planes going to be arrived at the same time or not? roscoe_x 16:19, 7 September 2005 (UTC)

In theory, yes, the same time. In practice, the plane which goes over the western hemisphere may have to climb a little higher to avoid Volcán Cayambe (4600m altitude on the equator), so might arrive slightly later. A more significant practical problem might be the weather, which could make it very difficult for the two planes to maintain identical ground speeds. - MPF 17:01, 7 September 2005 (UTC)

It depends on your assumptions. If the planes are travelling at the same speed relative to the ground, they will arrive at the same time. If they're moving at the same speed relative to the air, then it depends on trade winds and so on. If they're moving at the same speed relative to a co-moving Earth-centered inertial frame, then the westward moving plane will get their first, since the Earth's rotation is moving point B towards the westward plane and away from the eastward one. -- DrBob 17:26, 7 September 2005 (UTC)

To extend, in the third case, the eastward plane will "arrive" by way of the Earth catching up to the plane, assuming the plane is your standard sub-mach airliner or the like. — Lomn | Talk / RfC 20:52, 7 September 2005 (UTC)

Radioactive decay in molecules

When an atom in a molecule undergoes radioactive decay, what happens to the molecule? ‣ᓛᖁ♀ᑐ 16:30, 7 September 2005 (UTC)

Well I presume the other atoms in the molecule just float off and probably bond with other atoms/molecules is they are not stable. --βjweþþ (talk) 17:51, 7 September 2005 (UTC)

The charge on the atom would almost instantly change, but the exact effects would depend on the situation. In a metal, this would probably be no big deal as the extra electrons/holes would just flow freely around. In a crystal, you'd probably get something like this: Na₂₂⁺Cl^- (sodium chloride) beta decays to Ne₂₂Cl^-; the neon, being neutral, would float off freely, leaving a free chloride ion. If the original material was in solution, this would probably alter the pH. (Note: please feel free to fix my formatting, as I don't yet know how to use the <math> tags. The numbers in parentheses are isotopes, and the +/- show the charge). --David Wahler (talk) 20:12, 7 September 2005 (UTC)

differences and similarities

hello!

I am a Year 9 student at Tonbridge grammar school for girls and i am doing a project and i am in need of your help!

i am trying to find out between the differences and similarities between the following:

neon and argon neon and francium

i would be grateful if you could give me a list of the similarities or point me in the right direction of finding the answers.

thank-you charlotte

p.s i do not know where to contact you so sorry if this is the wrong email place.

Hi! If you're not sure where to look, you can start with the articles on each of those substances: Neon, Argon and Francium. You can also get to any of these articles by typing the name into the "search" box near the top-left hand corner of any Wikipedia page, and then clicking Go. --David Wahler (talk) 19:54, 7 September 2005 (UTC)

It should be noted that similarities tend to run vertically on the periodic table. Our article includes an excellent summary of element families that may point you in the right direction. — Lomn | Talk / RfC 21:00, 7 September 2005 (UTC)

Make sure to pay attention to what column the three elements are in. These columns have special names (noble gases and alkali metals) because they share a number of properties with other elements in the same column. This is historically how the organization of the periodic table was developed: by observing similarities between elements and grouping them accordingly. — Laura Scudder | Talk 21:06, 7 September 2005 (UTC)

motion sickness in games

i was playing gta sa and was attacked by motion sickness. is this normal? --Phil 1970 20:45, 7 September 2005 (UTC)

Before I continue, I'd like to point you to Wikipedia:Medical disclaimer - just in case.

I haven't played that particular game myself, but no, I don't think it is. It might just have been a freak occurence brought on by a number of outside factors, but if you're concerned or it happens again, I suggest you go see a doctor. --Pidgeot (t) (c) (e) 20:56, 7 September 2005 (UTC)

It's not too unusual. Motion sickness generally occurs because of a mismatch between what your eyes are seeing and what movements are detected by your inner ear (you can get the same effect in reverse by, say, reading a book in a moving car). First person shooters are a common culprit (for instance, bits of Half-Life 2 had to be redesigned because they were too nausea-inducing), though I could see GTA:SA giving the same effect. General advice is to play further back from the screen or monitor, so that you can see more of the surroundings (also, don't play in a dark room where all you can see is the screen). And take regular breaks, get up and walk around, etc., and don't play when tired. -- DrBob 21:03, 7 September 2005 (UTC)

I once suffered from this while playing an old 3D game (I think it was Heretic or Hexen). I think what caused this was that the 3D perspectgive was wrong. --R.Koot 00:29, 8 September 2005 (UTC)

• A lot of games can trigger migraines for me -- and my symptoms include motion sickness-like symptoms (vertigo, wooziness, slight nausea). The first one I noticed it on was Doom; lots of games that use similar motion can do it. But some games do it with no obvious similarity. Only takes about 5 minutes of play on the worst ones, and I feel like crap for a day. --jpgordon∇∆∇∆ 00:54, 8 September 2005 (UTC)

Technetium and Promethium

Note that both of these elements have no stable isotopes even though the ones next to them do.

Also note that if the Rare Earth (Lanthanides) are extended in place of the third period of the transition elements, Promethium appears right under Technetium. Also note that both atomic numbers are prime numbers whereas Manganese is not. Some discussion of if this is just coincidence or if there is a story to tell there would be interesting to me.

I would expect it's mostly coincidence. A proper extension of the rare earth elements pushes everything further right so that Technetium and Promethium do not align vertically, if I recall correctly.

That said, it's been a long time since high school chemistry. — Lomn | Talk / RfC 21:14, 7 September 2005 (UTC)

Name of an old 3D game.

I don't know where is the apropriate place, so I posted here. There was an old educational 3D game a la Wolfenstein 3D:

• two kids, a boy and a girl, inside a maze;
• two enter certain places in the maze, the kids (that is, the player, have to answer some questions about grammar, like:
  • insert commas in this frase
  • insert periods in the following text;
  • xyz is a synonim to......fill the blank line;
  • etc;

What is the name of that game, if you ever heard/played/know about it.

User:Mdob | Talk 22:03, 7 September 2005 (UTC)

Reaction effects of strong base to aqueous Gyloxal (ethandial)

Gyloxal (ethanedial)-C2H2O2- as 40% in water is listed as acidic (pH = 2.1-2.7)from the JT Baker MSDS.   

Why is this aldehyde acidic in aqueous solution?? What chemical changes would occur by neutralizing the solution to pH=6.0-8.0 with NaOH?? Would it become a carboxylate, sodium salt?? 64.154.26.251 22:33, 7 September 2005 (UTC)

LCD & Plasma

I want to know? LCD monitors are dangerous to the eyes? Robert Ackerman

They are less damaging than CRTs. But what exactly do you mean by "dangerous"? Is myopia a danger, or are you more concerned about, say, eyeball cancer?--inks 23:36, 7 September 2005 (UTC)

The following caution about liquid crystal displays came with my digi camera - if the LCD cover is broken and the liquid leaks out, and gets into your eyes, then "take the urgent action indicated": "flush the affected eye with clean water for 15 minutes, and seek medical assistance". Also if swallowed, "drink large amounts of water and induce vomiting, then seek medical assistance". Seems a rather unlikely scenario, but clearly the liquid in an LCD is toxic enough to warrant the caution and advice for medical attention - MPF 00:29, 8 September 2005 (UTC)

ice cubes

If I put two clouds of steam together, I end up with one cloud of steam. If I put two cups of water together, I end up with one cup of water. If I put two ice cubes together, I still have two ice cubes. What chemical/physical proces prevents solids from 'melting' together? --R.Koot 00:48, 8 September 2005 (UTC)

Steam and liquid water are the same thing. So the question simplifies to:

• What's the difference between the liquid and solid phases of water?

The answer is more mathematical than chemical/physical. In the (3D) interior of a ice cube the interactions between the molecules are weaker than in the (2D) surface (proof left up to the reader :-). Oh yes, Pauli speaked of the "surface hell".). So, the same forces/interactions tha keep the cube solid/coese, keep one cube apart from the other.

Err, sorry by my bad English, but hope this help. User:Mdob | Talk 01:15, 8 September 2005 (UTC)

This is basically the central problem of the study of adhesives -- namely, what causes molecules to stick together strongly within objects, but not between objects at surfaces, and how can this behavior be changes? --David Wahler (talk) 01:26, 8 September 2005 (UTC)

Ice lumps can fuse together easily under pressure - see Glacier#Glacial motion for details - MPF 01:30, 8 September 2005 (UTC)

In liquids and gases, the particles have enough freedom of movement to allow other particles to squeeze between them. In solids, the particles are nearly fixed in place and cannot move aside to admit more material. Thus, when two ice cubes are pushed together, the water molecules would have to pass through each other for the ice cubes to move any farther.

However, a water molecule is surrounded by a cloud of negatively charged electrons. While the molecules are overall neutrally charged, the electron clouds will encounter each other first, and will repel each other according to the very powerful electromagnetic force. Only an extreme amount of pressure — or the energy involved in a chemical reaction — could overcome this repulsive force.

This doesn't prevent the ice cubes from freezing together (hydrogen bonding) or from sticking together by vacuum cementation (Van der Waals force; both of these effects are also controlled by electromagnetism), but the water molecules cannot physically move through each other. ‣ᓛᖁ♀ᑐ 01:43, 8 September 2005 (UTC)

Question about scripting in Qbasic?

If you had to write a command to import numerical data from a .txt document, or something else like it, to be used in a qbasic program, how would you do it?? any help would be appreciated, thank you in advance--64.12.117.12 02:10, 8 September 2005 (UTC)

Pauli exclusion principle

Why are helium-4 atoms bosons? ‣ᓛᖁ♀ᑐ 02:38, 8 September 2005 (UTC)

A Helium-4 nucleus contains 2 protons and 2 neutrons, each of which is a fermion with spin of ±½. As a whole, the nucleus will have a total spin of +2, +1, 0, -1 or -2 - in each case an integer, so the nucleus is a boson. Compare a Helium-3 nucleus, which contains 3 nucleons, so the nucleus as a whole will have a total spin of 3/2, ½, -½ or -3/2 - in each case an half-integer, so the nucleus is a fermion. HTH. Now ask why the electrons don't matter :) -- ALoan (Talk) 11:37, 8 September 2005 (UTC)

mechanism for peptide bond forming reaction?

does anyone have the exact mechanism for this reaction, other than just, the n-terminal amino takes the place of the carboxylic OH, because everyone knows you make a CO2- into a good leaving group without a LOT of enzyme assistnce, thanks in advance--64.12.116.132 02:02, 8 September 2005 (UTC)

• It appears you have some knowledge of biochemistry, so I would recommend checking a copy of "Stryer's Biochemistry" at your nearest academic library. - Mgm|^(talk) 08:30, September 8, 2005 (UTC)

Logarithm common

The value of log2 is 0.3010, that of log20 is 1.3010 and that of log0.2 should be -1.3010

Is the above statement correct? When I checked up the value of log of fractional nos. (> 0 and < 1 I get wrong answers in Scientific calculators, MS Excel formula etc.

Whys is this so?

can I get a reply to my email ID vaidyaguru@yahoo.com or vaidyaguru@gmail.com

Okay I got the answer. The value is calculated as -1 + 0.3010 = -0.6990

Thanks Wikipedia anyway.

A Sun Line

Hello,

My name is Adam Rogers and I live in Conway, AR. On a roadtrip yesterday I noticed a horizontal black line which spanned the distance of the sun and no other parts of the sky. There were no clouds and no jet trails, even had there been they would not have blocked the sunlight in such a fashion. The occurence I observed lastted about 15 minutes and the black line followed the size of the sun from top to bottom as the line rose upwards across the sun. If anyone has seen a black horizontal line on the sun before or has any explanation as to why my eyes would have perceived such a thing I would appreciate the information. Again the line began as a small black dot on the bottom of the sun and began rising upwards across the sun growwing in length to match the exact circumference of the sun as I viewed it. The line continued to grow until it reached the 1/2 way point of the sun and then began to shrink as it began its ascent to the top of the sun.

24.144.63.26 05:01, 8 September 2005 (UTC)

• I don't know the anser to your question but having a look at out Sun article: "Caution: Looking directly at the Sun can damage the retina and one's eyesight". Please be careful. --Commander Keane 08:49, September 8, 2005 (UTC)

Make money on rising oil prices?

If I think that oil prices will continue rising, how do I cash in on that? Would it make a difference if I have $1000 or $1000000?

Well, you could buy and hold oil directly - but that will involve delivery and storage costs which could wipe out any theoretical profit. Or you could invest in oil futures or buy a call option on oil futures, which would give you economic exposure to the oil market without delivery or storage costs. Or you could invest in companies which could benefit from rising oil prices - maybe nuclear power companies or manufacturers of solar panels, wind turbines or bicycles ?? But you might want to re-examine your assumption that oil prices will continue to rise - there is an alternative view in this article, for example. Gandalf61 11:12, September 8, 2005 (UTC)

Is heated olive oil bad for you?

when i was single, my parents used to tell me that heated olive oil is as bad as saturated fat. I'm not very good at finding specific information online. As a result, now i know lots about olive oil, but nothing regards what i want to know. :) If anyone can help e i'll be very thankfull. Benedeta 08:44, 8 September 2005 (UTC)Benedeta