Wikipedia:Reference desk/Archives/Science/2009 February 18

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February 18

Hodgkin's lymphoma and GHB?

While searching on the internet about Hodgkin's lymphoma I found on wikipedia an article saying that one of the risk factors is "Prolonged use of human growth hormone". I kept searching clicking on "human growth hormone" and found maybe a relation between GHB abuse and lymphoma. Why isn´t this mentioned? Am I wrong, has someone studied about this?

When I heard about GHB, 10 years ago, it was said that there were still no known long-term secondary effects of it´s use. But if now it´s getting clearer, please inform people. My friend suffers from Hodgkin's lymphoma and he used regularly GHB but he also has Aids. So, where´s the connection? Is the lymphoma related to Aids or the abuse of GHB? Are we blaming AIDS for it forgetting the risks of using GHB? and because both diseases have the fact of being gay (aids & lymphome) or a man (lymphome) as one of the risk factors (although to say this is politically incorrect, I apologise, but it´s true) aren´t we mixing up things and making people believe that GHB has no long term severe secondary effects. Every website I found about GHB doesn´t mention this relation, but it mentions it´s use as rape drug. I know many cases of lymphome and a few of rape. Are we not making patients irresponsible? In the process of living with a cancer and facing it´s treatment it´s important not to blame yourself but at least know that your behaviour can deeply affect your health - a change of behaviour will help to cure. I wish I could say all this to everyone with the same problem in order to motivate a behaviour change to a healthy lifestyle and the strong belief in a cure, especially with withdrawing toxins and cancer agents and bringing in anti-oxidants through food. (we are what we eat/consume). I would much appreciate scientific answer/ explanation about this matter. And if there is a relation between and no one found out, I should get a prize. 217.22.90.231 (talk) 00:15, 18 February 2009 (UTC)

First thing, human growth hormone is completely different from and unrelated to GHB (Trovatore pointed out that GHB is used by bodybuilders), which is a can be used as a date rape drug. The acronym used for human growth hormone is HGH, not GHB. The following scientific articles I found address the issue of HGH and leukemias and lymphomas.

1. Critical evaluation of the safety of recombinant human growth hormone administration: Statement from the Growth Hormone Research Society. J Clin Endocrinol Metab 2001;86:1868 – 187025.. I would like to note that according the Growth Hormone Research Society webpage they are sponsored by a variety of corporate entities and thus may have outside interests. I do not know enough about the sponsership to make that call.
2. I found the following medical case report which requires a subscription to read. Nicola Magnavita, Luciana Teofili, Giuseppe Leone: Hodgkin's lymphoma in a cyclist treated with growth hormone. American Journal of Hematology, Volume 52 Issue 1, Pages 65 - 66. One quote is "The suspected relationship between GH use and hematological malignancies represents a further, strong reason to discourage this [doping using HGH] practice."
3. This paper found that HGH stimulated the growth of fresh patient-derived lymphoblastic leukemia and myelogenous leukemia cell lines. This paper and papers citing it seemed to conclude leukemia and lymphoma patients on an HGH treatment should be closely monitored, and that giving HGH to patients in remission is probably not a good idea since relapse risk increases.
4. This well cited paper collects various leukemia cases that have occurred in people treated with growth hormones. I can't read it so I'm not sure what it concludes.
5. Finally this commentary evaluates the scholarly writing and information available since 2004 and concludes the following:"There are no data to prove that the intrinsic risk of leukemia is further exacerbated by GH treatment, particularly if the dose of GH is at the level of physiologic replacement. Never-theless, this possibility requires serious consideration by the physicians and the families involved, and absence of data should not necessarily be construed to mean absence of an effect."' (Blanche P. Alter: COMMENTARY: Growth Hormone and the Risk of Malignancy. Pediatric Blood & Cancer, Volume 43, Issue 5 (p 534-535) )

I personally liked number 5 on my list of papers. From the limited exposure I have had to this topic from researching your question it seems like there is reasonable evidence that human growth hormone use (what level of use?) may increase the risk of relapse among leukemia/lymphoma patients. There is less than conclusive evidence that HGH use (what level of use?) may increase leukemia/lymphoma development risk in predisposed people but not enough research has been done to nail down whether this is true and to what extent if it is. I get the feeling that the most endocrine researchers do not think that human growth hormone increases the risk of leukemia/lymphoma development in healthy unpredisposed people. Concerning diet, you should look at Diet and cancer. Barring obesity, eating a well balanced diet at best only slightly reduces cancer risk. Other factors are more important in the development of various cancers than diet. 152.16.253.109 (talk) 03:53, 18 February 2009 (UTC)

AIDS and Non-Hodgkins Lymphoma (NHL) are certainly associated. NHL is the most common lymphoma affecting people with AIDS; NHL is an AIDS-defining illness in the presence of a positive HIV test. - Nunh-huh 04:37, 18 February 2009 (UTC)

A side note here: GHB is an extremely important pharmaceutical in the management of narcolepsy and cataplexy. It is very unfair to stigmatize it as a "date rape drug"; this tends to result in onerous regulation that makes it difficult for sufferers to get the medicine they need. --Trovatore (talk) 04:47, 18 February 2009 (UTC)

I'm sorry that I phrased my response poorly in case that is what bothered you; I didn't go any further than the disambiguation page while trying to figure out how the questioner had managed to associate human growth hormone with date rape drugs. I struck out the offending part of my answer. Thanks for pointing that out. 152.16.253.109 (talk) 05:07, 18 February 2009 (UTC)

Sure. I'm a little sensitive about this because a dear friend of mine ran into this issue back in the 90s.

As to the connection — according to our article, one of the uses (some will say abuses) of GHB is by athletes who use it to stimulate the in vivo production of HGH. So that part of it, at least, has some foundation. The rest of his contribution seems extremely speculative. --Trovatore (talk) 05:33, 18 February 2009 (UTC)

I'm doubtful the onerous regulation has anything to do with the stigmitisation. The onerous regulation has to do with the fact it is commonly used as a date rape drug. This is unfortunate for those who have a medical reason to us GHB I'm sure but is little different from the fact that pseudoephedrine is heavily regulated in many countries because it's commonly used to make methamphetamine. Now whether those regulations are really necessary or effective is a valid question but clearly not one for the RD Nil Einne (talk) 09:12, 18 February 2009 (UTC)

Do you have any references that it is "commonly" used as a date rape drug, other than tabloid newspapers? According to this paper [1], 46% of claimed date-rape victims had ethanol in their blood stream, compared to 2% with either a sedative or "disinhibiting" drug which includes MDMA and benzodiazepines, aswell as GHB. I don't have access to the full paper, maybe in there it states the exact number of claimed date-rape cases where GHB is involved. --Mark PEA (talk) 15:36, 18 February 2009 (UTC)

I'm a bit surprised that GHB says next to nothing about its subjective effects. A bit of OR if anyone's interested: I tried it once circa 1996 (before it got a bad name) and got a buzz resembling that of alcohol yet without feeling stupid; I spoke fluently and more rapidly than usual. —Tamfang (talk) 08:10, 20 February 2009 (UTC)

- Thanks for explanations. On the Wikipedia article about GHB says: "Some athletes and bodybuilders also use GHB, as GHB has been shown to elevate human growth hormone in vivo." Doesn´t this mean that GHB stimulates HGH? And if it stimulates HGH it might increase the risk of developing Lymphome especially on predisposed people, for example, patients with AIDS? So besides the relation between AIDS and the Lymphone is it or not possible that consuming GHB, by estimulating HGH, in predisposed individuals increases the riskof Lymphome?

- With regards to the fact (or not) of being used as a date-rape, as far as I know, GHB disappears from the body very quickly so it makes it difficult to be traced after a rape. What I know is that if someone is overdosed with GHB especially if mixed with alcohol gets into a complete unconscious state. GHB is easy to find among the recreational users and because it´s commonly associated with other drugs it might trigger unplanned rapes. Of course there are exceptions and all rapes are condemnable. And All this doesn´t mean that GHB shouldn´t be used to treat certain conditions. My friend that has Lymphome started to smoke cannabis to get rid of the horrible pain that results of the treatment, and it surely works. 217.22.90.231 (talk) 19:06, 19 February 2009 (UTC)

Ionic Strength: am I doing it right?

I'm trying to figure out the ionic strength of a solution used for inducing insect flight muscle contraction. My PI couldn't help me with this, so I'm asking here. In short, my question is am I doing this ionic strength calculation right? The formula for ionic strength is given here. The components of the solution with concentrations are listed below. I included relevant pKas for the weak acids/bases. I can't figure out if pKa matters in this context since pKas are affected by ionic strength.

15mM Na₄ATP (ATP pKa = 6.5)

15mM Mg(OAc)₂ (acetic acid pKa = 4.76)

5mM CaCl₂

20mM NaMOPS (Mops pKa = 7.20)

5mM EGTA (EGTA pKa = 6.91) (I have no clue whether or to what extent a chelator of calcium will affect the ionic strength contribution of calcium present)

5mM NaN₃

Below I have separated the above into ions assuming complete dissociation for the salts and that the concentration of dissociated EGTA is negligible.

species	concentration	charge	ionic strength
Na	85mM†	+1	42.5 *10-3
ATP	15mM	-4	120 *10-3
Ca	5mM	+2	10 *10-3
Cl	10mM	-1	5 *10-3
MOPS	20mM	-1	10 *10-3
Mg	15mM	+2	30 *10-3
OAc	30mM	-1	15 *10-3
EGTA	5mM	0	0
N3	5mM	-1	2.5 *10-3

† That 85 mM is from 4*15mM + 20mM +5mM

The sum of all of those is 235 *10^-3. Did I do the calculation right? If it helps, I know from experience the pH winds up being between 5.3 and 5.8 (I think 5.6?) and if I replace the 5mM CaCl₂ with 10mM NaCl (a sum of 230 *10^-3) the pH winds up being between 6 and 6.5 (I think 6.3?). I pH the solutions to 6.8 using sodium hydroxide afterwards, but I'm not going to worry about this yet because I want to make sure that I am doing the ionic strength calculations correctly in the first place. And a bonus question: If I have an enzyme that is in the form of a disodium hydrated salt, is it safe to assume for the purposes of ionic strength calculation that the enzyme will act as a divalent anion when in solution? 152.16.253.109 (talk) 02:42, 18 February 2009 (UTC)

My math agrees with yours, but I don't have much experience with ionic strength per se. I would expect EGTA to chelate the Ca++, but will "donate" an equivalent amount of cation in doing so, so this should not have much effect. Do you think your enzyme will be in a high enough molar concentration to have an impact? Others here may have more specific feedback. --Scray (talk) 04:57, 18 February 2009 (UTC)

I'm thinking about using creatine kinase at 300 units per mL. It is 185 units/mg. If 42 kilodaltons is the molecular weight, 1 unit per mL works out to be 1/7700 mols/L 1.29*10^-7 mols/L so 300 units/mL is ~39mM 0.039mM which if divalent will add an extra ~117*10^-3 0.117*10^-3: a 50% 0.05% increase in ionic strength. (edit. redid those calculations and found I was off by a factor of 1000... I think that I am not going to need to worry now...21:33, 19 February 2009 (UTC)) 152.16.253.109 (talk) 05:39, 18 February 2009 (UTC)

Are you confident that 185 units/mg represents a direct conversion of enzyme units to mg of pure enzyme? I'm not. Using Google I see preparations with at least 1000 units/mg, which results in a more than 5-fold decrease in the estimate of enzyme molarity at 300 units/mL. Depending on the ionic strength of impurities, the other stuff in the prep has unpredictable effects. You might want to look for a really pure prep, or at least talk to the vendor about what they might know about ionic strength - the scientists at some of these labs are quite knowledgeable and accessible. I'll go back to my earlier point - it seems unlikely to me that an enzyme would be present at a high enough concentration to affect things like osmolarity, ionic strength, etc. Also, be careful about Dimensional analysis - I think you assumed that the "mg" in "185 units/mg" was "mg of enzyme", when it's actually "mg of fairly pure enzyme". --Scray (talk) 12:13, 18 February 2009 (UTC)

Same person, different IP. 185 units/mg is what the little plastic bottle says. I'm going to trust it. This is rabbit muscle derived creatine kinase by the way and an ... older batch at that. You are right about the prep being only fairly pure, but the contaminants are at most 5 percent by dry weight so their impact is (hopefully) reduced. It's better just to go ahead and try it out than to get mired down by trying to account for everything. If things go pear shaped, I'll give the makers a call, but as long as I have done the calculations above right I will go ahead and salt the solution to match the predicted ionic strength. I will also run a control using an "normal" solution batch too. I appreciate your advice so far, Scray! 65.190.207.110 (talk) 01:37, 19 February 2009 (UTC)

You have not said why you think contaminants are less than 5% by dry weight, but I wish you the best. I urge you to sign in using a username - the benefits are substantial, and I don't know of a substantial downside. --Scray (talk) 03:54, 19 February 2009 (UTC)

Voltaic pile chemistry

I have to teach a grade school science class in a few days. If anyone can provide the answer to these questions, thanks. Otherwise it is dustbowl empiricism. I plan to make a Voltaic pile and electrochemical cells. 1)How many grams of salt should be added per kilogram of water to make a saturated solution? 2)If zinc and copper are the electrodes used, would saturated saline solution or 4% acetic acid (vinegar) produce higher voltage and higher current? 3)Would a combination of vinegar and saline produce more voltage\current than either separately? 4)Would dilute sulfuric acid (perhaps one part battery acid to 10 parts water, such as was used in the early 19th century)) produce more voltage/current with zinc and copper electrodes than vinegar and/or saline? Thanks. Edison (talk) 05:46, 18 February 2009 (UTC)

I don't know about the other questions (you'd have to look up electronegativity tables, I think), but for #1 take a look at the infobox on sodium chloride. Confusing Manifestation(Say hi!) 05:55, 18 February 2009 (UTC)

That source says "35.9 g/100 mL (25 °C)" for solubilty of salt. Presumably the conductivity and output current of a copper/zinc cell would be maximum with that amount of dissolved salt in a Voltaic pile or electrochemical cell. Sounds good. How does that compare to vinegar or a vinegar/salt mixture, or dilute sulfuric acid for output current? I am looking for maximum short-term power, not long term output, which might involve adding nitric acid to dilute sulphuric, or which might require amalgamating the zinc plates with mercury (currently a big no-no, but common 19th century practice). I hate science fairs which have "potato batteries" with tiny zinc and copper electrodes and which can barely power an LED light or a wristwatch. Real batteries in the first decade of the 19th century produced substantial current and voltage, such as the 2000 volt, 1.5 amp battery Davy built at the Royal Society circa 1808. Edison (talk) 06:39, 18 February 2009 (UTC)

The easiest way to make a saturated salt solution is to get warm water and heap salt into it and shake it up, adding more salt until no more goes into solution. Then pour off the supernate. Unless you need to know how much salt goes into the solution don't bother. 152.16.253.109 (talk) 07:20, 18 February 2009 (UTC)

This google result seemed especially useful. I'm afraid the rest of this answer will fall under "dustbowl empiricism". I know from experience that leaving copper in a saturated salt in vinegar solution for more than an hour will tend to brown/pit the surface of the copper and may corrode the zinc. If you go with something like this and don't intend to replace the electrodes after every use, add the solutions just before starting, and wash off the electrodes with distilled water afterwards if you intend to reuse it. I've done a lot of chemistry demonstrations for schools and it is vital that you try out your cells beforehand, so you can sort out "irregularities" and are sure of what behavior to expect from the device. I would avoid bringing a sulfuric acid mixture if something else would work. If something spills it is more psychologically reassuring to the school, the teacher, and the kids' parents to know that it was just salt and vinegar or a little ammonia and salt rather than sulfuric acid or dilute battery acid. I'm sorry these are not the specific answers you wanted. 152.16.253.109 (talk) 07:12, 18 February 2009 (UTC)

If you are going to have the kids do the experiment - why not make it a proper experiment. Have some kids use saline and others use vinegar and see which ones get the best results. I agree that you should probably avoid sulphuric acid - even in 10:1 dilution it's not very nice stuff. This experiment is kinda messy because you have to stack these cells together to get a reasonable voltage out of them - so the possibility of getting dilute sulphuric acid on hands and/or clothes is high. SteveBaker (talk) 13:56, 18 February 2009 (UTC)

Probably will use brine and blotting paper for the Voltaic pile. I was considering making up one "state of the art 1808" cell with the dilute acid typical for the period we are covering, in addition to the usual wimpy potato battery. to show that an amp or so could be obtained for a short while until bubbles on the plates increased the internal resistance, in contrast to the milliamp or so from little dissimilar metal pieces stuck in a lemon or potato. I will forge ahead and test it out ahead of time. Is it to be expected that closely spaced electrodes in an electrochemical cell will produce higher current? Edison (talk) 18:14, 18 February 2009 (UTC)

Electrode spacing seems to matter little with 200 ml of concentrated brine solution.Edison (talk) 19:55, 18 February 2009 (UTC)

Bacterial illness

My doctor told me that bacterial illnesses are mostly caused by more than one kind of bacteria. Is that true?

More generally, what is known about combinations of infecting agents (be it bacteria or others, possibly mixed)? 93.132.168.56 (talk) 08:15, 18 February 2009 (UTC)

In short: It's true. Many infections come in common "packs", so having an infection with one pathogen makes it much more likely to have a very specific secondary infection. For example: The common cold is caused by a viral infection, but this viral infection paves the ground for secondary bacterial infection. Such "combinations" of pathogens are rather common and can be regarded as a kind of symbiosis from the side of the infectious agents: they combine their abilities to be better able to infect the host. As for a very simplisitic functional explaination: Most infections interfere with our immune system, and in doing so they make it easier for other pathogens to proliferate in the infected region. Wikipedia does not really have much content for this topic, as most articles like superinfection and coinfection are very narrow and miss the biological point. TheMaster17 (talk) 10:32, 18 February 2009 (UTC)

When those in the advanced health professions study bacteria, they learn that there are a whole bunch of bacteria than normally live in and on the body. When you get a bacterial infection, it is usually because you are exposed to a virulent bacteria (one that has a well developed ability to cause infection). These bacteria usually secrete sticky substances that allow them to grow easily in large groups, like streptococcus growing in your sinuses. The other bacteria that normally live there without causing symptoms are then provided a great place to thrive and thus grow in much larger amounts than usual. Normally all you have to treat in these cases is the causative agent. However, most of the drugs that are prescribed in these cases are "shotguns" in the sense that they will probably kill all of the culprits anyway.

--Mrdeath5493 (talk) 17:44, 18 February 2009 (UTC)

So my doctor is wrong is stating that bacterial illnesses are mostly caused by more than on kind of bacteria? 93.132.168.56 (talk) 20:01, 18 February 2009 (UTC)

I won't go so far as to contradict him directly. I think he is referring to the fact that when our normal defenses against pathogens are compromised, the normal bacteria that live in and on us cause infection and they cause it all at once. The statistics about how common that and other mixed infections are is a doctor's field and I would say he knows what he is talking about. For a straight answer you would probably have to turn to epidemiology. Most epidemiologist are physicians and study things exactly like what you are talking about. I would think that bacterial infections would be among the most studied subjects within, but they tend to vary widely depending on your location within a state, not to mention your country or the world.

--Mrdeath5493 (talk) 20:18, 18 February 2009 (UTC)

I would disagree with the assertion that "most epidemiologists are physicians". At least in the US, training in epidemiology is a separate Master's or PhD level pathway that does not necessarily involve medical training. While it is true that some physicians do obtain extra training in epidemiology, they do not make up the majority of epidemiologists. --- Medical geneticist (talk) 21:16, 18 February 2009 (UTC)

Yeah you're right. *Many* are. --Mrdeath5493 (talk) 21:46, 18 February 2009 (UTC)

Neither would I openly contradict a doctor: they are in possession of our bodies and our health. I will have a look at epidemiology- Thank you so far. 93.132.168.56 (talk) 20:48, 18 February 2009 (UTC)

I'm currently studying this topic, so I decided to do some extra reading. I have referenced enough creditable sources to say that most bacterial infections are the result of exposure to a specific virulent bacteria. Diagnosis and subsequent treatment is based on identifying an exact bacteria to treat. However, I still won't say your doctor is wrong. I think what he meant was what I said in my initial response. After one infectious strain invades, it does provide a suitable environment for the overgrowth of others that were there to begin with. I will say he could have used a better word than "cause." ;) Also you could interpret that statement to mean something entirely different than what you did. He could have just meant that not all bacterial illnesses are caused by the same bacteria. So I would say to fault our own perception before faulting his intention.--Mrdeath5493 (talk) 21:56, 18 February 2009 (UTC)

Funny, my original question to the doctor was why couldn't we have a specific analysis of the infecting bacteria and have a specialized treatment for just that kind instead of broadband antibiotics. 93.132.168.56 (talk) 22:13, 18 February 2009 (UTC)

Perhaps there is a misunderstanding of what your doctor told you. For any given episode of infection, there is probably one main culprit at that given time and place. However, for any classes of infections, say ear infections or bacterial pneumonia or bacterial meningitis or urinary tract infections, there are a few "most commonly causing" organisms followed by a long list of "also can cause" organisms. This could be the explanation that your doctor was trying to give, when s/he told you that "bacterial illnesses are mostly caused by more than one kind of bacteria" as opposed to the explanations about superinfection and coinfection. --- Medical geneticist (talk) 22:45, 18 February 2009 (UTC)

With regard to antibiotic selection, the physician might start empirically based on the most likely pathogenic organism, or treat with a broad-spectrum antibiotic to get most of the likely culprits, or simply go by published guidelines (such as the AAP Red Book) that indicate how to treat a particular infection. There are certainly some cases where a bacterial culture and sensitivity will be performed to identify the pathogenic organism and treatment options, but not in every case. Keep in mind also that your own immune system is fighting the infection at the same time, so even a suboptimal antibiotic regimen may be enough to help you fight off the infection sooner. It is even argued that for certain types of infections we should avoid treating with antibiotics (thus reducing antibiotic resistance) and simply let the body take care of its own business. It sounds like you already have a good dialogue going with your physician and should continue to ask good questions! --- Medical geneticist (talk) 22:45, 18 February 2009 (UTC)

Ok, judging by your original question User:Medical geneticist has the answer I believe. It would require too much time, effort, and money to identify the exact bacteria in most cases. When your doc said many different bacteria cause infections he meant it could be any one of a number of possibilities. Just as an example I remember the normal flora and likely causes of infection in the sinuses with the acronym HAPPEN

H. influenzae

Aureus (referring to staph)

Pnemococcus (S. pneumoniae)

Pyogenes (referring to strep)

Epidermitis (referring to staph)

Neisseria

Of all those Strep. pneumoniea is by far the most likely. We know that it is overwhelmingly (~97% of strains) resistant to Penincillin, so we have to go with an Aminopenicillin like Amoxicillin or even skip that step and go with a Z-pack (very common). However, herein lies the flaw. Over half of people that present with symptoms of a sinus infection have a viral infection (which antibiotics will do nothing about.) Anyway before I get to far off the subject, when you doctor said more than one bacteria cause infection he was referring to situations like the list above (it could be any of them!). Your doctor knows what he is talking about.--Mrdeath5493 (talk) 23:42, 18 February 2009 (UTC)

So if any one infection is caused by a main culprit, why don't we have a PCR analysis to know what it is and subsequently treat that special one, avoiding to use antibiotics on viral infections or resistant strains? Is it too expensive yet? I imagine an analysis chip, produced in huge numbers with costs of few dollars, later even cents, that does a PCR and is sensitive to a few dozen of the most common critters. 95.112.165.196 (talk) 08:30, 19 February 2009 (UTC)

There are plenty of analytic methods that can determine the culprit, including PCR, it just depends on the situation whether or not your doctor goes to the trouble of finding out. Some things to consider in the equation: 1) the ease with which a sample can be obtained and the specificity of the culture results, 2) the utility of determining the exact organism (will it change your management?), 3) the severity of the consequences for the patient (this will also take into account the age and general health of the patient).

Examples:

• Meningitis - somewhat difficult to get a sample (you have to perform a lumbar puncture), but critical in terms of knowing whether the patient has viral or bacterial meningitis. You absolutely don't want to let a person go untreated who has bacterial meningitis (in fact, most of the time the patient is treated empirically with broad spectrum antibiotics until the culture results come back after ~48 hours). The balance therefore almost always goes toward testing.
• Urinary tract infection - easy to obtain a urine sample and perform a standard culture, useful in guiding therapy (there are a wide variety of bugs that can cause UTI), UTI is generally not immediately threatening to the patient but you certainly don't want it to progress to a kidney infection if not treated properly. The balance usually goes toward testing.
• Otitis media - usually caused by a few different bacteria that can be treated similarly. It's impractical to obtain a sample of the pus for testing (by performing a myringotomy) and the typical ear infection will resolve on its own even if untreated. Hence, the balance goes toward empiric treatment using expert guidelines that have been developed.
• Pneumonia - also caused by quite a few different organisms including viruses and bacteria. If the patient is coughing you can get a sputum sample but it will contain all sorts of bugs and therefore the specificity of the test is a little questionable. You could go further and get a bronchoalveolar lavage but this is a pretty invasive thing to do to someone for a routine case of pneumonia. In the end, the balance depends a lot on the overall health of the individual. Some cases will be treated empirically with a broad-spectrum antibiotic and other cases will be tested to determine the specific culprit and treated accordingly.

The bottom line is that the course taken for any given patient depends entirely on the circumstances and doesn't really boil down to a universal "lab-on-a-chip" test that instantly spits out information. This is why physicians go through as much training as they do, to be able to grasp all the uncertainties and come up with the right course of action. --- Medical geneticist (talk) 15:02, 19 February 2009 (UTC)

Al Jazir, Ancient Engineer?

I'm looking for a Wikipedia article on an early engineer by (what I think is) the name of Al Jazir. I believe he would have been alive in the same time as Archimedes, but that guess is a shot in the dark. I know The Discovery Channel did a few documentaries on the subject. His work was in elaborate timepieces and other scientific devices; perhaps in the vein of the Antikythera mechanism and other such devices. Also possible to been alive in the same time as the peak of Alexandria. Again, I'm almost certain the name was Al Jazir, but having searched all over I must have the spelling incorrect. Any help is much appreciated!

Siouxdax (talk) 09:58, 18 February 2009 (UTC)

Doing a google search on "al jazir" and "mechanic" quickly brought up the name "al jazira" and/or "al jazari". We have a page, but he is not even close to contemporary to Archimedes. But he was a mechanic and has build time keeping mechanisms. TheMaster17 (talk) 10:16, 18 February 2009 (UTC)

That is exactly what I was looking for! I don't know why I thought he was in the same time as Archimedes. Thanks so much! Siouxdax (talk) 10:25, 18 February 2009 (UTC)

Clarification required

All I wanted to do was increase my knowledge of the cubit stick, the first unit of length. But what was stated is a bit of a joke. suggest some-one tries watching the TV programme by the BBC (UK).

To even think it was invented by an Egyptian Pharoah would be pushing the realms of commonsense.

The cubit stick was invented by the person in charge of designing a building, and not a pyramid as stated here. The pyramids were built using precise measurements, so how could one have been built before units of measurement were invented?

For a verifiable source try the BBC —Preceding unsigned comment added by 121.221.4.199 (talk) 10:49, 18 February 2009 (UTC)

I'm guessing you have read Cubit and in particular Cubit#History_of_the_different_cubits? If you believe the article to be incorrect i'd suggest discussing it on the relevant talk-page for the article, and cite your sources. 194.221.133.226 (talk) 11:20, 18 February 2009 (UTC)

The cubit incidentally, as described in our article was a unit of measurement (actually different ones were used by different people) so it clearly can't predate the invention of units of measurements Nil Einne (talk) 13:28, 18 February 2009 (UTC)

I don't see what's wrong with the article. The unit of length known as 'the cubit' has changed over time - different civilisations used different measurements. So when the Egyptians were building their pyramids, they would have chosen a standard for the cubit and stuck to using that exact measure for all of their work and everything would have come out OK. But the ancient Greeks used a different standard - yet they still called it 'the cubit'. The ancient Romans had yet a different measure with the same name. That wasn't at all confusing for them because each civilisation picked some distance and stuck by that - but it's VERY confusing for us looking back. To give you a concrete example - I spent some time a few years ago doing pro-bono computer graphics work for the guys who built a very carefully researched replica of a Greek Trireme (a kind of war-ship, rowed by a bunch of oarsmen) - it's called "Olympias". (I wrote a trireme battle simulation: [2] based on the performance data from the Olympias and was able to prove that some previous assertions about the way they fought could not possibly be true.) The guys who were figuring this out had the problem that no trireme has ever been found - not even the smallest part of these huge wooden structures has survived. But they knew how long the ship should be (in modern units) because they found remains of a shipyard where these vessels were built and stored - but when they came to figure out how the rowing benches were laid out, all they had was a written account that described the dimensions in cubits. Sadly - the account was written by someone who was not a native Greek and who used the 'wrong' distance for a Greek cubit. As a direct consequence of this, the rowing benches on the Olympias are just a couple of inches too tightly bunched and the people who have manned this modern replica don't have enough space to row efficiently. (It doesn't help that modern humans are on average a little taller than the ancient Greeks - but that's not the main reason). So the cubit article (as far as I can tell) is perfectly OK. Do you have a specific problem with it? SteveBaker (talk) 13:44, 18 February 2009 (UTC)

I betcha the Egyptians and Greeks didn't call it a cubit, unless they were speaking Latin. (It's the Latin word for 'elbow'.) —Tamfang (talk) 08:22, 20 February 2009 (UTC)

Electron composition

what is an electron made of?Vipinchandranp (talk) 13:52, 18 February 2009 (UTC)

Have you even tried to read electron ? As you could read there, the electron has no known substructure. So it is, as far as we know at the moment, a fundamental particle. TheMaster17 (talk) 14:06, 18 February 2009 (UTC)

Whoever find the answers to this question wins more than a couple of noble prizes.Sjschen (talk) 16:13, 18 February 2009 (UTC)

RadioShack Weather Stations

Does Radio Shack sell any weather stations that can hook up to your computer for data upload? If so, what is the cheapest but most reliable.Nick (talk) 15:27, 18 February 2009 (UTC)

I don't think that I got it at Radio Shack, but I have a little clock/weather station thing. It has a clock, internal temp/humidity sensor, outside (linked by radio) temp/pressure sensor, and it tunes into some AM-frequency (I think) national weather service. It has a USB connector to connect it to a PC to dump the history of readings. Looking at it, I'm rather surprised that it doesn't have a make/model. It is mainly a see-through LCD display with a small black plastic base. From memory, it was made by La Cross. Checking http://www.lacrosstechnologies.com/ will likely find something similar to what you want. -- kainaw™ 17:19, 18 February 2009 (UTC)

Following EC: Yes. [3] [4]. If you are looking for what a particular retailer has to offer, it's best to go to their web site and search there. Alternatively you can use search terms with ".." in google (like "Radio shack", "weather station", USB, PC) That will narrow down results. You can then google for reviews of a model you like. These people [5] might be willing to share their opinions. [6]--76.97.245.5 (talk) 17:31, 18 February 2009 (UTC)

If you do get a PWS, please consider hooking it up to www.weatherunderground.com so that everyone in the world can check it! Franamax (talk) 00:04, 19 February 2009 (UTC)

Is there any scientific evidence backing 9/11 conspiracy theories?

I am currently embarking a major project to clean up all the articles relating to 9/11 conspiracy theories. Part of the problem is that 9/11 conspiracy theorists keep trying to insert their conspiracy theories into the articles as if they are legitimate. Another part of the problem is that some good-faith editors don't quite understand what WP:NPOV really means and inadvertently give too much undue weight to fringe theories. I am planning on starting with the main article on 9/11 conspiracy theories. I've already posted my intent on the main article's discussion page, [7]. I will proceed until every article on 9/11 Truth Movement, Loose Change, etc. is in accordance to WP:NPOV. In order to be fair and balanced, what I would like to is this. Are any reliable sources from the scientific community claiming that 9/11 conspiracy theories are true? A Quest For Knowledge (talk) 15:50, 18 February 2009 (UTC)

"The Scientific Community" at large cannot possibly comment on "conspiracy theories at large," you will really have to handle these on a case-by-case basis. For example, there was a lot of talk early on about the melting-point / breaking point of structural steel; I think a lot of construction engineering sources will be able to specifically comment on the structural integrity. But there are a lot of conspiracy-theories ranging from very minor political intrigues to very extreme, space-alien-interventions. It will be much easier to evaluate specific claims scientifically, rather than trying to lump all claims together. Nimur (talk) 16:04, 18 February 2009 (UTC)

There will be all kinds of reliable scientific sources that support the individual arguments of conspiracy theorists, but generally only when taken out of context and with lots of unlikely assumptions. I doubt you'll find any peer reviewed papers explicitly saying that there is a conspiracy regarding 9/11 (not in legitimate science journals, anyway - there are plenty of less legitimate journals that will publish anything), it's not really a scientific question - scientists may address individual points in the theories, but not the theory as a whole. --Tango (talk) 16:20, 18 February 2009 (UTC)

Well, me be blunt. I doubt that there are many if any reliable scientific sources that explicitly support 9/11 conspiracy theories. I suspect that the answer to my question is zero. Nevertheless, I still want to go through the excercise of actually trying to find out. Tango, you mentioned "There will be all kinds of reliable scientific sources that support the individual arguments of conspiracy theorists, but generally only when taken out of context". For the purposes of my question, the sources should specifically mention 9/11 conspiracy theories. As far I undestand the policy, to do otherwise violates the WP:SYN clause of WP:NOR, correct? A Quest For Knowledge (talk) 16:41, 18 February 2009 (UTC)

Well, if the sources are referenced by the conspiracy theorists then you can mention them without it being OR. If you want to try and find some reliable sources, take a look through these search results. I've looked at the first couple of pages and see a few things debunking the theories, most of the rest looks irrelevant. (You may be able to come up with better search terms - that was just my first attempt.) --Tango (talk) 17:25, 18 February 2009 (UTC)

Popular Mechanics did a well recieved debunking of the most popular conspiracy theories concerning 9/11.

--Mrdeath5493 (talk) 17:26, 18 February 2009 (UTC)

Yes, Popular Mechanics did an excellent job. They even turned their article into a book [8], but finding reliable sources to debunk 9/11 conspiracy will be easy. The hard part will be finding reliable sources that are in favor of 9/11 conspiracy theories. A Quest For Knowledge (talk) 17:46, 18 February 2009 (UTC)

One oddity (not necessarily due to a conspiracy: failures in design and operation (diesel fuel stored throughout on occupied floors)or in firefighting could doubtless equal the effects of a diabolical conspiracy) is that 7 World Trade Center, a modern highrise building which was NOT hit directly by an airplane, but set on fire by debris from the collisions, is the only modern high rise to collapse due to a fire. There was a recent case where a high rise in China was completely involved in flames due to fireworks and basically destroyed, yet did not suffer collapse. There is more than one kind of conspiracy. Besides terrorist conspiracies, more often one finds conspiracies to coverup poor decisions. The emergency power needs of tenants in a high rise should be supplied via cables from emergency generators and automatic throwovers to alternate utility feeders, rather than by having fuel storage tanks and fuel pipelines running through occupied floors. Another coverup (no media attention) has been the fact that after the NY Police Department helicopter rescued people from the roof of one of the World Trade Center building after the bomb blast in the 1993, the NY Fire Department asserted that rescue was their sole right, and insisted on automatically and securely locked exit doors from the restaurant to the roof, which could be opened only electrically from the command center in the middle of the building. This center was knocked out by the airplane hit, dooming any hopes of rescue from above. Yeah, I know the investigation said such rescue was impossible. The securely locked doors prevented anyone getting out on the roof to test the abilities of chopper pilots to lower a cable. In 1993 the Emergency Services Unit (police) had the ability to rappel from a twin-engine rescue chopper hovering at 1500 feet and chopping down obstructions so the copter could land. The north tower had a smoke-free area from which some of the trapped people could have been rescued, but for the fire department (which had no helicopters) insisting on rescue only by walking down the destroyed and impassible stairs. Face-saving assertions in investigatory reports also constitute conspiracy. Other post-attack conspiracies might involve denial of the danger from the dust that workers had to breathe. Edison (talk) 18:05, 18 February 2009 (UTC)

20/20 hindsight is, as always, an incredibly impressive and incredibly useless ability. --Tango (talk) 19:06, 18 February 2009 (UTC)

If anyone had asked my advice on how to provide emergency power to an office high up in a building, I would have strongly criticized in advance the notion of storing fuel at various locations in an office building. It is contrary to common and recommended practice. Ditto for making it impossible to get out to the roof of a highrise, when the possibility of air rescue had been demonstrated. "Everyone can always walk down the stars" is faith-based evacuation. The 20/20 hindsight quibble usually applies to things no one could have foreseen. Edison (talk) 00:28, 19 February 2009 (UTC)

No, it applies to everything. It's easy to say "I would have foreseen that" after the event. --Tango (talk) 01:28, 19 February 2009 (UTC)

Put it this way: so far as the issue of scattering generators around with fuel storage tanks on occupied floors: I installed emergency power prior to 9/11 in numerous places and did not do it that way, because it is idiotic per se. Put the fuel far away from office space and bring in electrical cables. This is a giant "DUH" factor, not really an either/or question so far as safety is concerned. Not "2020 hindsight" quibbling to defend the indefensible. People in NY City likely wanted vanity stroking generators after the outage of the 1960's and had the illusion that they were better off with the generator next door, and never mind the fire hazard. A careful search of the files would likely find objections by qualified electrical engineers and fire safety experts which were overridden by executive know-it-alls. Edison (talk) 04:39, 21 February 2009 (UTC)

I think the other question is whether sources will actually say such a theory happened - they are far more likely to show that it could have happened (i.e. "there's no reason why the government didn't have this involvement") which is far short of a sources suggesting it did. - Jarry1250 ^{(t, c)} 21:11, 18 February 2009 (UTC)

Does this count as scientific evidence? [9] - Azi Like a Fox (talk) 22:42, 18 February 2009 (UTC)

Er... no. --Tango (talk) 01:28, 19 February 2009 (UTC)

As I mentioned above, I believe that the articles relating to 9/11 conspiracy theories are giving undue weight to fringe theories. But right now, I am focusing on researching the topic. In the coming days/weeks (depending on the amount of my free time) I will probably raise a NPOV issue with the NPOV Noticeboard. If any rational skeptics (and I am sure that there are plenty on this board) would like to assist me in my efforts, your help would be greatly appreciated. However, before I raise the NPOV issue, I want to do more research so I am prepared to present a thorough case. For now, my initial thoughts can be found on main article's discussion page, [10]. If you'd like to help, feel free to add this page to your watchlist. A Quest For Knowledge (talk) 03:41, 19 February 2009 (UTC)

Thanks Tango for the Google Scholar link. I wasn't aware that such a thing exists. A Quest For Knowledge (talk) 02:39, 20 February 2009 (UTC)

Speculation on Glaucoma and HSV

Has any there been any research to determine if there might be any connection between Herpes simplex virus type 1 (HSV-1) (cold sores) and glaucoma?

1. From http://en.wikipedia.org/wiki/Glaucoma it's clear that "Raised intraocular pressure is a significant risk factor for developing glaucoma" but is not the exact cause. It's clear because "in some populations only 50% of patients with primary open angle glaucoma actually have elevated ocular pressure.", there is an "inconsistent relationship of glaucomatous optic neuropathy with ocular hypertension", and "another person may have high eye pressure for years and yet never develop damage".

Read to the bottom of http://www.nei.nih.gov/health/glaucoma/glaucoma_facts.asp and you find the exact cause of glaucoma is unknown.

2. "Glaucoma is a group of diseases of the optic nerve involving loss of retinal ganglion cells". OK, now have a look at http://en.wikipedia.org/wiki/Herpes_simplex. "After initial infection, the viruses move to sensory nerves, where they reside as life-long, latent viruses" and "Following a primary infection, the virus enters the nerves at the site of primary infection, migrates to the cell body of the neuron, and becomes latent in the ganglion."

Do the latent viruses damage the ganglion? Do frequent recurrences or outbreaks damage the sensory nerves? Does it only migrate to the primary site of infection or could it migrate to the optical ganglion?

3. There is currently a new drug under development for glaucoma; "Peripherally selective 5-HT2A agonists such as the indazole derivative AL-34662 are currently under development and show significant promise in the treatment of glaucoma." and from http://en.wikipedia.org/wiki/5-HT2A_receptor "5-HT2A also happens to be a necessary receptor for the spread of the human polyoma virus called JC virus."

Is this just coincidence as the author implies by the phrase also happens to be? Is the polyoma virus related to HSV in any way? Both can cause latent infections. Could the 5-HT2A receptor also be a factor in HSV infection?

4. Here's something which really surprised me at http://en.wikipedia.org/wiki/Herpes_simplex and http://en.wikipedia.org/wiki/Alzheimer_disease;

"Scientists discovered a link between HSV-1 and Alzheimer’s disease in 1979" and "Recent research supports the previously obscure theory that Herpes simplex virus type 1 plays a role as a possible cause of AD in people carrying the susceptible versions of the apoE gene".

In some people Herpes simplex 1 causes Alzheimer's disease and brain damage!? That's extremely interesting in itself, but back to conjecture; could HSV damage the optic nerve?

Think about it !!!!!!!!

Just kidding, and I don't expect any prizes either. Also I'm asking about the common "Orofacial herpes", not "Ocular herpes ... a special case of facial herpes infection, known as herpes keratitis", although I find it interesting that there is an ocular form of the disease. Feline herpesvirus http://en.wikipedia.org/wiki/Feline_herpesvirus_1 herpes also has ocular symptoms. Poor Bertie, he was such a handsome cat.

Finally I've read this over several times and can't see any way in which it could be interpreted as a request for medical advice.

Thank you.Stevej000 (talk) 16:35, 18 February 2009 (UTC)

Well you might love this then: "Herpes simplex virus: an important etiology for secondary glaucoma." Jones R 3rd, Pasquale LR, Pavan-Langston D. Int Ophthalmol Clin. 2007 Spring;47(2):99-107. Review.
I can't even find an abstract for it, let alone the entire paper. Someguy1221 (talk) 18:29, 18 February 2009 (UTC)

My university has access to this paper (which doesn't seem to have an abstract). I'm not supposed to be forwarding these things out, so if you don't email me then I won't email you back reasonably quickly with the paper as a PDF attachment. Honest. – ClockworkSoul 21:37, 18 February 2009 (UTC)

ClockworkSoul, you are a candidate to work at the Resource Exchange, where we never ever do that kind of stuff, none of the time. Nice work! :) Franamax (talk) 01:20, 19 February 2009 (UTC)

Thanks again folks, I no longer feel like a total crackpot! Stevej000 (talk) 12:07, 19 February 2009 (UTC)

Is it a coincedence 2... ?

http://www.islamreligion.com/articles/215/

just follow this and tell me what do you think....? —Preceding unsigned comment added by Mjaafreh2008 (talk • contribs) 17:06, 18 February 2009 (UTC)

This is the last of these questions I'm going to answer, and only briefly - I won't be posting any follow-up. I still don't think you're really listening to what we say anyway. "Peg" is a very vague word, and not one I would use to describe the shapes in the diagrams in that article. The shape of a mountain above the rest of the surface could be better described as a peg (upside-down) - it's wide at one end and narrow at the other, which most pegs I've seen are. I'm not sure I've ever seen a peg that was wide in the middle and narrow at both ends. As for the stability thing, I've never heard of mountains stabilising the Earth, but if they do then I guess it's just a coincidence, yes. --Tango (talk) 17:19, 18 February 2009 (UTC)

After edit conflict - Is 'what a coincidence? You provided no textual explanation of what subject your talking about, let alone what the actual question is. I shouldn't have to click an off-site link just to find out what your question is. A Quest For Knowledge (talk) 17:21, 18 February 2009 (UTC)

I'm not answering these piecemeal from now until eternity. As I offered before - if our OP will make ONE question containing a list of all of these claims in a neat little numbered list, I'll be happy to answer them all in one go. But we don't need these long threads every time one of these questions comes up because each time we have the same set of replies about the question being too vague or whatever. It starts to look trollish - and we don't feed trolls here. So - please make a complete list of all of these 'The Quran claims...' questions and ask them all at once in one question - then we can answer that and call it a day. Thanks! SteveBaker (talk) 18:50, 18 February 2009 (UTC)

How you'd really get anybody here to sit up and take notice is if you can find somebody who was inspired by a passage in the Koran to look for evidence showing that what people thought was wrong. For instance if before tectonic drift was accepted someone said their holy book says the earth is split apart in the middle of the oceans and they went ahead and found the mid Atlantic ridge, then you'd get a few converts maybe. I don't suppose you'd find such evidence compelling but, trust me, it really is he sort of thing which would excite a scientist. They can be quite gullable with just a little real evidence. Dmcq (talk) 20:06, 18 February 2009 (UTC)

The simple answer to this, and any other related questions, is that the author of the website is taking what is clearly intended to be a piece of metaphorical writing, finding a correspondence in science, and trying to make a point from it. I've seen plenty of the same thing done with the Bible. Typically you will find there are other similar metaphorical statements that happen not to be scientifically true; if you ask the website's author about them he will say "they are just metaphors". DJ Clayworth (talk) 21:54, 18 February 2009 (UTC)

Exactly - in the very same place where it discusses mountains as 'pegs', it says (18:47): "On that day we shall remove the mountains, and thou wilt see the earth as a level stretch"...in other words, the Quran says that the earth is flat. It says this not just once but in many places: 13:3, 15:19, 18:7, 19:6, 21:30, 35:40, 41:10, 43:10, 50:7, 51:48, 55:10, 78:6, 79:30 and 88:20. One or two of those might be intended figuratively - but all of them? If you can pick and choose between hundreds of statements - you're bound to find one or two true ones amongst many, many false ones. The question is whether it would have made predictive statements that people could use. Clearly it cannot because it's saying so many things that are clearly false. But this isn't unique to the Quran - it's true of every other religious book you might come across. The christian bible says (Matt 4:8) "Again, the devil taketh him up into an exceeding high mountain, and sheweth him all the kingdoms of the world, and the glory of them."...something that's only possible if the world is flat. The Torah kinda-sorta says the Earth is round - but it still says things like (Psachim, p.94b), the Gemara states that fountain waters at night are warmer than by day because the sun warms up the water during the night from underneath the earth. SteveBaker (talk) 23:08, 18 February 2009 (UTC)

A perfect sphere is, from the spheres perspective, a perfectly two dimensional (flat) area. Gravity operates on a two dimensional plane. The difficult one is magnetism which operates on a one dimensional plane. The Bhagavad Gita and the Śrīmad Bhāgavatam were describing spiritual theories on Anti matter thousands of years before Abraham was around. It is strange coincidence that such works always prove the more popular. ~ R.T.G 05:35, 19 February 2009 (UTC)

The problem with all of that is none of it is science. Look, to bring back the analogy I made last time this came up, a blindfolded man may hit a bullseye in a game of darts once in a while; it doesn't mean that darts should properly be played blindfolded. Merely because ancient texts propose ideas which, if read liberally and with lots of squinting, could possibly maybe refer to modern scientific concepts; it does not mean that such texts are "scientific" in any way. Science is not a collection of facts or statements about the world; its a process that leads to an understanding of the world. If a conclusion is reached that one did not arrive at by science, then the conclusion is not scientific, even if scientific processes eventually reached a similar sounding conclusion later. The Bhagavad Gita did not describe anti-matter. The Bhagavad Gita described stuff that, after physicists discovered what anti-matter was, could kinda-sorta be seen to have some parallels to actual anti-matter. It doesn't mean that the Bhagavad Gita is a scientific text!!! --Jayron32.talk.contribs 06:41, 19 February 2009 (UTC)

I love how some people trust the ravings of a lunatic 1000-2000 years ago who thought he heard God/an angel, and choose to distrust the decades or centuries of observation, experimentation, and logical reasoning by well-educated people using advanced equipment that has lead to modern science. Our OP may be a little better because he may not think science is crap, but still, to think the Quran and real evidence are equal shows a degree of irrationality I cannot comprehend. --Bowlhover (talk) 07:12, 19 February 2009 (UTC)

will ,, its all been said before, but , why dont we take the quraan as an exception , assuming it could be true,without comparing it to other books. first ... assuming its just coincedences , this could be true if you find one or two but it will be more that acoincedence if you find alot more . but first make sure that you do understand it completely . after all ... its your search to do .. some will say its just crap and others will look for the truth ... after all this argument , i think the result will be nothing ,,, theres alot to talk about ... and theres alot of ides . so ... this link will be my last contribution in this subject

http://www.55a.net/firas/english/

thank you for the concern —Preceding unsigned comment added by Mjaafreh2008 (talk • contribs) 14:21, 19 February 2009 (UTC)

Not many years ago, someone found a lot of surprising 'predictions' hidden in the Torah, and wrote The Bible Code. People scoffed that you can find anything you like by the approach he used, if you look cleverly enough. The author challenged skeptics to find, by the same approach, a prediction of the assassination of a prime minister in Moby-Dick. They did, abundantly. To ask us to consider whether the Quraan is special, without comparing it to other books, is unscientific: to measure specialness, we need to know what is normal. —Tamfang (talk) 08:35, 20 February 2009 (UTC)

Questions which are vague and just say "Look at this web site and tell me what you think" do not seem like legitimate material for the Reference Desk. "Tell me what you think" is not a legitimate question. Such questions should be removed in the future. If the questioner has a question, he should ask the question, and not direct us to click on some web site. Edison (talk) 04:45, 21 February 2009 (UTC)

conservation of energy

suppose we have two capacitors charged accordingly and then the positive terminal of one is joined to the negative terminal of the other & vice versa then there occurs a loss in electrostatic energy,i.e. the initial electrostatic energy that was stored in the two capacitors was more than it is after short circuiting the two. WHERE DOES THE ENERGY GO?? {note:the loss occurs even if we use resistanceless wires}--scoobydoo (talk) 17:38, 18 February 2009 (UTC)

There will be an electrostatic attraction between the terminals before they connect, that would involve a loss of energy. Whether it accounts for all the energy or not, I don't know...

If they are real world capacitors there are dielectric losses (leakage current) and series resistance (ESR). http://en.wikipedia.org/wiki/Capacitor. If they are ideal capacitors I don't know.Stevej000 (talk) 18:21, 18 February 2009 (UTC)

Anything that doesn't dissipate in the resistance will be radiated as an electromagnetic wave as the charge bounces back and forth. The wire forming he loop will have a small inductance. Dmcq (talk) 18:30, 18 February 2009 (UTC)

Global warming. Cuddlyable3 (talk) 00:17, 19 February 2009 (UTC)

>>the whole problem comes from a physics book i found which says that two capacitors 5microF & 6microF were charged across 24V and 12V resp and then connected with reistanceless wires the +ve terminal of first one with the -ve terminal of the second and asks about this loss. I calculated the initial energies as 1.44mJ and 0.432mJ {applying E=1/2cv^2} and the loss comes out to be 1.77mJ upon redistribution of charge.If the attracion is responsible as you say then the work done by these forces will be stored as electrostatic potential energy which should be accounted for by the eqn.Another notable thing is that if the +ve plates are joined together than also there is loss but it is less than the previuos one which also remains unexplained.

One useful analogy for this problem is a mass-spring system, but with the Spring constant replaced with capacitance and deflection replaced with voltage. With such substitutions, the equations for stored energy and total series capacitance are preserved. Then with the values given, it is more intuitive to see that when the two "springs" are coupled together, they will begin oscillating. Someone42 (talk) 10:40, 20 February 2009 (UTC)

Adenoidectomy

So my brother is getting his adenoids (Pharyngeal tonsil) out and I was doing some research to see what the procedure is, side-effects, etc. when I came across this line near the end of the Adenoidectomy article: "Adenoidectomy is often performed on children aged 1-6, as adenoids help the body's immune system." This makes absolutely no sense to me; if they help the body's immune system, wouldn't it be useful to have them during your childhood years? Also, if anyone has had this procedure done / knows about it and wishes to give me some info, it would be much appreciated. The article is a little sparse. Thanks! -Pete5x5 (talk) 19:36, 18 February 2009 (UTC)

P.S. Just in case anyone was wondering, I'm not requesting medical advice; my brother has already spoken to the appropriate medical professionals and is getting the procedure done regardless of how much I know about it.  ;) -Pete5x5 (talk) 19:39, 18 February 2009 (UTC)

This procedure is very common because some small children have recurrent infections affecting their tonsils. Although it sounds bad, removing them is almost always done in an effort to prevent infection. Check out the Tonsillectomy article.

--Mrdeath5493 (talk) 20:30, 18 February 2009 (UTC)

Following EC: I'm not anywhere near an expert. I assume that the sentence means that the operation helps the body fights an infection like Streptococcal pharyngitis and Tonsillitis. The fewer repositories for pathogens are in the body the less work the immune system has to do. It doesn't say anything about it being done as a prophylactic measure. The phrase should probably we reworded. 76.97.245.5 (talk) 20:32, 18 February 2009 (UTC)

Seems like some undue confusion and a poorly written article here. The adenoids and tonsils are part of the immune system, somewhat like lymph nodes, that are involved in the immune surveillance of the nasopharynx and oropharynx. These tissues can get inflamed, swollen and painful when a person gets an acute infection (either with a virus or bacteria) -- it's like a battleground where your immune cells are fighting, killing, and dying. Having the adenoids or tonsils removed does NOTHING to help the body fight off infection. They aren't typically "repositories" for pathogens. The entire human body (including the nose and mouth) is essentially a microbial culture chamber (it's just that most of the "bugs" we live with don't cause problems most of the time). While removal of the tonsils and/or adenoids may prevent them from becoming infected in the future, this isn't why they are removed. Some reasons given for surgery include chronic infections such as an abcess or symptomatic enlargement that leads to difficulty breathing (sleep apnea) or feeding. --- Medical geneticist (talk) 21:36, 18 February 2009 (UTC)

OK, for my own curiosity then: why do the adenoids and tonsils get inflamed? Presumably they are not the primary targets of infection, so what brings the battlefront to them? Macrophages that can't keep their meal down? Dendritic cells that get infected with an intracellular pathogen and then migrate? What exactly is the mechanism that causes inflammation in those tissues? Franamax (talk) 01:13, 19 February 2009 (UTC)

Inflammation is not the same thing as infection. Secondary lymphoid tissues (tonsils, adenoids, other gut-associated lymphoid tissue [GALT], in addition to lymph nodes and spleen) can become inflamed in the process of generating specific immune responses (B and T cells) for antigens delivered by blood (to spleen), lymphatics (lymph nodes), or the mucosal surface (tonsils, adenoids, other GALT). Sometimes these tissues do become infected, but I just want to emphasize that inflammation does not mean infection. That being said, the processes that bring antigens to these tissues can also bring the pathogens (floating free or contained within phagocytic cells). --Scray (talk) 04:09, 19 February 2009 (UTC)

These are part of Waldeyer's ring. Don't these lymphatic tissues have an important role as part of the immune system in fighting infections? Or are they "just along for the ride" as one doctor once told me? Edison (talk) 04:53, 21 February 2009 (UTC)

It would be great if we understood "macro" elements of the immune system that well, but we don't. I can speculate about why the Waldeyer ring is important, and have read quite a bit about it, but systems biology is in its infancy. --Scray (talk) 05:31, 21 February 2009 (UTC)

The tip of a laser beam

A Klingon bird of war drops out of the Star-trek universe and finds itself in our Einstein universe. Furious to be deprived of all those fictional technologies, they fire all their weapon systems to see which still work. A debate starts as the laser gun doesn't produce the well-known and picturesque streak of light. The captain says the laser could not work in this universe because, the laser beam as all electromagnetic waves has to obey the Maxwell equations. On the other hand the speed of light is limited, so the beam has a "tip" in front of which nature has no chance of knowing that the beam will arrive in an epsilon of a second. Space there has to be absolutely undisturbed by the not yet arrived beam, and this would contradict with any solution of the Maxwell equations.

What's wrong with that argument? What does the tip of the laser beam look like? 93.132.168.56 (talk) 20:44, 18 February 2009 (UTC)

Why does that contradict the Maxwell Equations? If you solve the equations the speed of light just appears naturally, it's fully part of the solution, it isn't something that Einstein added on later. --Tango (talk) 20:59, 18 February 2009 (UTC)

Well, obviously it doesn't. But it's strange that a continuous and differentiable field should have a "tip" where it gets constantly zero. So how does the tip look like? 93.132.168.56 (talk) 21:11, 18 February 2009 (UTC)

It looks like the frontier of a wave, because that's what it is. I guess it will be gradual - the laser won't turn on in an instant, it will take a certain (very small) amount of time to get from zero to full power. --Tango (talk) 21:17, 18 February 2009 (UTC)

I assume you mean "look like" metaphorically? You obviously can't see the tip unless it is on your retina, in which case it looks like a point of light. --Tango (talk) 21:18, 18 February 2009 (UTC)

You are not giving medical advice, are you? 93.132.168.56 (talk) 21:28, 18 February 2009 (UTC)

Since the laser is question was from a Klingon Warbird I'm guessing your retina had better register it pretty quickly before it, along with the rest of you, is fried. DJ Clayworth (talk) 21:46, 18 February 2009 (UTC)

With "look like" I mean what does the field equation look like. And I will also be satisfied if someone can point me to what the wave front (field equation in a neighborhood) of a spherical electromagneticale wave looks like, because it's there but it doesn't exist further away than c times t from its origin. 93.132.168.56 (talk) 21:28, 18 February 2009 (UTC)

Nor could it - if it did, that would imply that some aspect of the field was travelling faster than light - and that's a "no no". Information can't travel faster than light - so if some kind of field disturbance arrived ahead of the light itself then you could (in theory) know that the Klingons fired the laser before the beam itself arrived - which would imply that the information travelled faster than light. SteveBaker (talk) 23:35, 18 February 2009 (UTC)

Causality occurs only within the light cone that describes temporal evolution. Within it, you use the standard equations. Outside of it, you have no idea that the events in question have happened yet, so you don't care. I don't understand the confusion though - everyone knows that Star Trek was a documentary. :) Franamax (talk) 00:19, 19 February 2009 (UTC)

The electromagnetic wave equation is:

${\Bigg (}\nabla ^{2}-{1 \over {c}^{2}}{\partial ^{2} \over \partial t^{2}}{\bigg )}\mathbf {E} \ =\ 0$

For the sake of illustration, let's assume spherical symmetry, so this reduces to:

${\Bigg (}{1 \over r}{\partial ^{2} \over \partial r^{2}}r-{1 \over {c}^{2}}{\partial ^{2} \over \partial t^{2}}{\bigg )}\mathbf {E(r,t)} \ =\ 0$

It is straightforward to demonstrate that any solution of the form:

$\mathbf {E(r,t)} ={1 \over r}f(c\ t-r)$

Will satisfy the wave equation, where f is absolutely any twice differentiable function of one variable. The condition that the wave originates at r = 0 and time t = t₀ is simply the constraint that f(a) = 0 for all a ≤ c t₀. Otherwise Maxwell's equations allows the traveling wave to have absolutely any twice differentiable pulse shape. Dragons flight (talk) 01:01, 19 February 2009 (UTC)

Thank you, now I see. f could be (composed of) some patchwork function like $f(s)=s^{3}$ for $s>0$ and $f(s)=0$ else. 95.112.165.196 (talk) 08:35, 19 February 2009 (UTC)

(I edited the math in the above to make it a bit clearer.) Vespertine1215 (talk) 16:31, 19 February 2009 (UTC)

Why did doctors administer calomel and bleeding in the 18th and 19th century?

Calomel is a mercury compound which doctors in many countries routinely administered to anyone who was sick or injured in the 18th and 19th century. "Calomel" redirects to Mercury(I) chloride. That article says it was given as a "purgative" until the patient salivated, but [[Purgative} redirects to Laxative. Which end of the patient was the doctor trying to get something from? Benjamin Rush used it in the 1790's to "remove poisons from the body" although the calomel was itself known to be poisonous and ancient medical writers had said as much. Did no one in the medical colleges try a series of patients with and without administration of that poison and bleeding? A surgeon of the 1840's administered calomel and bleeding to patients with severe head wounds, and cites 4 cases of patients recovering from penetrating head trauma, sometimes with brain tissue exposed (he might not be mentioning those who died). Mercury compounds and bleeding along with other likely lethal treatments were given to President Harrison ([11] Botanico-Medical Recorder, 1841,Vol X, No. 2, page 22). That publication charged (1841, Vol X, No 1., pagepage 23) that calomel and bleeding had likewise killed former President Washington. I find botanical doctors to be the ones criticizing mercury as the standard cureall of the 19th century medical establishment ([12] Vol X, No. 1, Oct 16, 1841, pages 13-15), along with bleeding. Only around 1910 do books seem to cite data showing calomel was ineffective and detrimental to health. Can we be confident today that the bleeding and calomel were in every instance detrimental to the patients' recovery (Definitely not seeking medical advice)? Edison (talk) 20:49, 18 February 2009 (UTC)

Not quite sure what is up with calomel, but if you haven't already you might want to check out bloodletting. I'm pretty sure in the 18th century a lot of medicine was based in religion and superstition, so who knows why they did what they did. Something I find interesting is the medieval use of leeches in medical treatment has somewhat returned (European Medical Leech).

I can't imagine either calomel or bloodletting being beneficial in any way. I think it would be safe to say that, in general, they were detrimental. Think about your response if a doctor told you that they were about to just let you bleed as a treatment for anything. Now, as an antibacterial safety mechanism, bleeding does flush out a wound; but intentional cutting is another story.

--Mrdeath5493 (talk) 21:03, 18 February 2009 (UTC)

There is (as far as I know, exactly) one disease in which the modern primary treatment is periodic bloodletting, that being polycythemia rubra vera. Bloodletting is used occasionally for a few other diseases in the present, though generally not as the primary treatment. So we can be assured that nearly all 19th century bloodletting was detrimental, but not all. - Nunh-huh 00:05, 19 February 2009 (UTC)

You could also add hemochromatosis to the short list of conditions that benefit from a good bloodletting. --- Medical geneticist (talk) 00:26, 19 February 2009 (UTC)

...and some porphyrias. --Scray (talk) 04:12, 19 February 2009 (UTC)

The practice of medicine in the 18th and 19th centuries bears little resemblance to today's medicine. In general, practitioners of that era probably did not systematically study the efficacy of their remedies. The concepts of randomized controlled trials (or as you put it, "a series of patients with and without administration of that poison and bleeding") are a modern phenomenon. See epidemiology and various links within evidence-based medicine. See also patent medicine for other examples of quackery promoted as "medicine". At least in the USA, regulation of medicines is a 20th century phenomenon. --- Medical geneticist (talk) 21:13, 18 February 2009 (UTC)

Oh yeah don't forget to check out Maggot therapy too.--Mrdeath5493 (talk) 21:15, 18 February 2009 (UTC)

While you are at it, be sure to miss Purification Rundown which promises you bonus IQ points as you get purer.Cuddlyable3 (talk) 00:14, 19 February 2009 (UTC)

In History of medicine#Modern medicine the 18th and 19th and even early 20th century doctors get a total pass from any criticism of their fanatical devotion to bloodletting and calomel. The discussion of "modern medicine" just claims that in the 19th century there were all these great advances in chemistry and bacteriology. The section appears to be in serious need of balanced historic coverage of actual medical practice, and the harm likely done to many patients by bloodletting and the administration of heavy metals, in efforts to "remove poisons." Edison (talk) 22:38, 18 February 2009 (UTC)

Looking here, vomiting is mentioned so it seems that mercury chloride causes pretty general upset. "Saliva" could be a generic term that covers esophageal reflux / mini-pukes, i.e. when stuff comes out of the patient's mouth, you know you've given them enough "medicine".

As far as help/hinder, well at least it's not methylmercury (the really bad kind) and it seems pretty obvious that the body has a vested interest in getting rid of it. This could actually have some beneficial effects, such as dramatically reducing the population of intestinal parasites; and in general, system challenges can have a stimulating effect if they don't kill you outright.

I'd imagine that any beneficial effects would be totally random though, and selection bias would lead people to only report the ones that "worked". You are talking about a period of history when the concept of statistical analysis had not yet been dreamed up. Until that concept came along, it's fair to issue a free pass.

And anecdotally in re the early-20th century, in the 1910's and 20's there was a brief craze to use thorium as a general curative. It did seem to work in small doses, possibly because of the stimulative effect of toxins very low on the dose-response curve (but I've been shot down on the hormesis idea here before :). Then, people who used more of it had to get parts of their jaw removed because of tumours &c and it kind of died off after that... I don't have a link for that and I gave away the history magazine I read it in long ago, but it did happen! Franamax (talk) 00:49, 19 February 2009 (UTC)

Let's not be too judgmental of those who went before us. I'm sure that most practitioners of the art were well-meaning, even if they were ignorant of the ways things really work. We too could be subject to harsh criticism by Wikipedians of the 22nd century... ("Can you believe they used to use surgery to take out the appendix??? How barbaric!" or "What about the chemotherapy and radiation therapy they were using -- how much harm did they do to people with those supposed therapies?") --- Medical geneticist (talk) 00:31, 19 February 2009 (UTC)

While we're indicting the old medical establishment, remember that good old-fashioned lobotomys, administered basically with an icepick through your tear duct, were still being given as late as the 1950's. Rosemary Kennedy had her brain scrambled in 1941; it was considered a "cutting edge" procedure then... --Jayron32.talk.contribs 04:43, 19 February 2009 (UTC)

One book I found noted that when the "allopath" or "real doctor" from a medical school came in say the 1850's he did venisection (bloodletting) with his lancet first thing, as surely as his present counterpart would listen to the heart and lungs with his stethoscope. This immediately caused the patient to settle down and stop raving and thrashing around, decreased the fever and flushing. Of course it also put them one foot in the grave from loss of blood, but to family members it may have seemed an improvement. If Gramps died after the doctor dosed him and bled him, it was "God's will." Then the calomel and other harsh drugs caused vomiting and bowel movements, which had some face validity as "flushing out the poisons." A downside of calomel was loss of teeth and of pieces of the jawbone. Other "alternative" practitioners likely did no more good with their herbal remedies, but usually did less harm. The typical 19th century doctor's visit with the typical bloodletting, calomel and emetic, apparently caused about as much trauma as present day chemotherapy, with no benefit whatsoever. They likely caused greatly increased morbidity and mortality compared to the control condition of no doctor visit, until doctors understood the germ theory and had treatments for bacterial infections. This does not deny the effectiveness of surgery to suture wounds and set broken bones: patients often benefitted even though the surgeons were unaware of germs. Edison (talk) 05:06, 21 February 2009 (UTC)

Purple Orange

File:PurpleOrange.JPG

My mom was peeling oranges when she came across this ! Does anyone know why? Bewareofdog 23:09, 18 February 2009 (UTC)

It looks like a blood orange to me. Why it would be mixed up with regular oranges, I don't know. --Tango (talk) 23:17, 18 February 2009 (UTC)

If they were in adjacent bins, one might easily grab one by mistake. —Tamfang (talk) 08:39, 20 February 2009 (UTC)