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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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]
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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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:

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

Each bar represents the frequency of edits done per month.
Now, draw another graph, with the same horizontal axis. (I just replaced the month names with numbers here instead)
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:

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)

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)[reply]

(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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

Thanks guys

Where can I find information on James De Politerno who uses massage therapy?

Deep yellow sky

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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.

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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

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

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)[reply]

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)[reply]