Science desk
< June 30	<< Jun \| July \| Aug >>	July 2 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

July 1[edit]

Malaria[edit]

Does malaria exist in Japan since its common in Asia? Clover345 (talk) 07:40, 1 July 2013 (UTC)[reply]

statement by banned user retained only because it was answered

The following discussion has been closed. Please do not modify it.

No. Malaria does not occur in Japan. Malaria is spread by mosquitoes and requires a hot tropical climate that supports mosquitoes. Malaria is mainly a problem in tropical jungles that combine high temperatures with plenty of water for mosqitoe larvae to grow in. Japan is too far north of the equator and is thus not a hot tropical jungle region. Malaria cases occured in Japan when soldiers returning from World War 2, having caught it in jungle areas, but as there was no means to efficently spread the disease, once the soldiers recovered, there was no more malaria. See http://idsc.nih.go.jp/iasr/18/213/tpc213.html — Preceding unsigned comment added by 124.178.183.4 (talk) 11:21, 1 July 2013 (UTC) statement by banned user wickwack[reply]

Thats so gabbled and inaccurate that it does not start to answer the OP's question. There is no indigenous malaria in Japan anymore because the intermediate host (i.e., humans) infected by malaria are too few now to sustain a reservoir of this disease (due to modern anti -malarial drugs). The climate of southern Japan suits the vector (mosquitos) very nicely (as your ankles will witness in the evenings when they come out to bite). --Aspro (talk) 12:01, 1 July 2013 (UTC)[reply]

Indeed. Malaria was also endemic to Britain until the 1950s, when land drainage and modern healthcare eradicated it. Britain's climate is similar to Japan's, and the assertion that Malaria "requires a hot tropical climate" is nonsense. ref. -- Finlay McWalterჷTalk 13:26, 1 July 2013 (UTC)[reply]

Regarding malaria in Britain, our article on the history of malaria says "Malaria was once common in most of Europe and North America, where it is now for all purposes non-existent ... in the coastal marshes of England, mortality from "marsh fever" or "tertian ague" ("the ague" from Latin "febris acuta") was comparable to that in sub-Saharan Africa today". Gandalf61 (talk) 15:17, 1 July 2013 (UTC)[reply]

Yep, the climate is suitable. According to http://idsc.nih.go.jp/iasr/18/213/tpc213.html there were estimated to be "...20,000 cases of indigenous malaria per annum before the World War II" in Japan. Of course, the anti-malarial drugs and mosquito controls were sufficient to end its malaria problem. If Japan is anything like North Carolina, there have always been enormous numbers of them buzzing biting insects to deal with (we have a particularly large land area and plenty of swamps!). Targeted killing works though. --Modocc (talk) 11:48, 2 July 2013 (UTC)[reply]

There are conflicting accounts regarding Malaria's history in Japan, but the mosquito Anopheles sinensis found in Japan is known to be a vector for Plasmodium vivax (it is apparently refractory to P. falciparum). Malaria is found in many non-tropical areas; for example, it was endemic in much of the United States at one time. -- Scray (talk) 11:38, 1 July 2013 (UTC)[reply]

There is a meta-discussion regarding the dynamic IP address at the reference desk talkpage here http://en.wikipedia.org/wiki/Wikipedia_talk:Reference_desk/Science#WickWack_is_back. --Modocc (talk) 04:02, 4 July 2013 (UTC)[reply]

How would certain wikipedians do in the World Quizzing Championship?[edit]

Really, some of you show an incredible depth of general knowledge when answering questions... I wonder how some of you would do as quizzers in the World Quizzing Championship? I'm posting this here because I was hoping for a scientific answer. Do these quizzers really have an excellent general knowledge like some of you do, or do they have a different type of brain that is trained to retain bits of trivia? On this matter, it seems to me that some of their quizzing questions are a bit contrived and generally limited to western knowledge rather than true global knowledge... I wonder how these so-called eggheads would do given a random sampling of wikipedia's "did you know" questions? Sandman30s (talk) 14:08, 1 July 2013 (UTC)[reply]

Not sure. I participated in academic competitions (in the U.S. called Quiz bowl) of various forms throughout HS and College, such as Granite State Challenge, Academic Competition Federation, College Bowl, National Academic Quiz Tournaments, etc. I have a few trophies. --Jayron32 14:33, 1 July 2013 (UTC)[reply]

I suspect that most Ref Desk denizens would fare no better than an average person (although there are exceptions). What we do (or at least, what we're supposed to do) is to use Wikipedia and other online information to find references in order to answer questions - and according to the US WQC site: "The World Quizzing Championship takes the form of a written quiz taken by individuals using no reference materials". Kinda the opposite of what we do. Being good at answering RefDesk questions really requires a broad - but very approximate - base of knowledge, combined with being clever at using search engines in creative ways. SteveBaker (talk) 14:34, 1 July 2013 (UTC)[reply]

I also think it's quite likely that many of the regulars would object on principle to supporting an organization that thinks a "quizzer" is someone who answers questions, and "quizzing" is the process of answering questions. See quiz. Tevildo (talk) 19:20, 1 July 2013 (UTC)[reply]

The average person believes a large number of things that simply aren't true and actually knows very little geography, history, or science. Personally, I would like to imagine that the average Ref Desk responder is at least a little better informed than the average person on the street. At the very least most of the people here at least have some interest in thumbing through the fascinating bits of our encyclopedia, and might just remember some of what they read. Dragons flight (talk) 20:49, 1 July 2013 (UTC)[reply]

For SteveBaker, I would add from my experience that answering questions on the ref desk seems to be about adopting the most pedantic interpretation of a question that you can, and giving a silly answer to it. I've seen this quite a lot. As far as this question goes, I think most brainiacs would find it very easy to answer the "did you know?" questions: they would just say "yes" to all of them. And if that's not pedantic, I don't know what would be. As for the question, Australian quiz champ Vincent Smith just said to read widely. It means you would usually have a very good general knowledge. It would not necessarily be deep, but you would be more than just a fact machine. IBE (talk) 09:20, 2 July 2013 (UTC)[reply]

I agree that there is an unfortunate tendency to do that. It's much easier to produce a stupidly pedantic/silly answer than to figure out the true answer and reply properly. We try to discourage this kind of bad behavior and to "weed out" the individuals involved - however, this is "The Encyclopedia That Anyone Can Edit" - and unless these people are actively breaking our rules, it's hard to ban the useless ones. Also, there is a problem that there can sometimes be a thin line between a stupid answer and a decent one. Often our OP's need to be a little patient in order to get the answer they need! SteveBaker (talk) 14:39, 2 July 2013 (UTC)[reply]

Version:1.0 StartHTML:0000000167 EndHTML:0000001417 StartFragment:0000000484 EndFragment:0000001401

Comment: I think some silly answers are posted by people who take after Marvin the Paranoid Android who has a brain the size of a planet but is never given the chance to use it. They may well 'feel' (as opposed to think) that some eloquent posters of questions could get far quicker -all most instantaneous- answers by taking this advice (?):[[1]]. In my experience for example, a good librarian is one that not only finds your answer but shows you how you can navigate your own way to answering your next question. Of course, if a poster to a question doesn’t know how to navigate, using what s\he already knows (and to cross reference as a check, that the info is sound) – then their options are limited and thus we are here to help. Well, some of us. ---Aspro (talk) 19:57, 2 July 2013 (UTC)[reply]

Two questions about the blood donation or blood test[edit]

Hi, I would like to ask two questions about the blood donation or blood test: The first question is: How long after donating blood or blood test that takes the blood to produce the same amount of the blood out of out from the body as I understand it is a process which takes time to create blood cells in the bone marrow and does not ends up by drinking liquids ...

And the second question is: Is there is any advantage physiologically in a blood test? (Note, I'm not talking about the importance of the tests themselves but if there is any _ benefits in taking blood out from the body in the case of an ordinary person who is not suffering from polycythemia - Multiple in taking blood). Thank you. מוטיבציה (talk) 15:35, 1 July 2013 (UTC)[reply]

I don't have an answer for the first question, but for the second question, our article on bloodletting says that it is not considered beneficial except for a few specific conditions, most notably iron overload. Looie496 (talk) 17:46, 1 July 2013 (UTC)[reply]

According to the UK blood service "it takes several weeks for all the red cells to be replaced [after a donation]". Platelets and white cells are replaced "over the next few days". The minimum gap between donations in the UK is currently 12 weeks for men and 16 weeks for women, but for donations by apheresis (where the red cells are returned to the body during the donation) the gap is less (a month when I used to do it, though that was quite a while ago). AndrewWTaylor (talk) 17:59, 1 July 2013 (UTC)[reply]

Note that the amount of blood taken in a blood test is "only a small amount" [2] whereas a blood donation (in the UK at least) is 470 ml [3] or 0.83 of an Imperial pint, plus various samples that are tested for HIV, hepatitis and so on. Alansplodge (talk) 20:36, 1 July 2013 (UTC)[reply]

what is the purpose of the breathing from mouth to mouth in CPR?[edit]

What is the purpose of the breathing in the life support CPR? I heard that the goal of the mouth among 30 massage of the heart is actually to stimulate the respiratory system or the control area in the brain responsible for breathing, by carbon dioxide (CO2). Until then, I thought that the goal is just to put oxygen into the mouth of the unconscious person. I'd love to sort the issue. Thanks מוטיבציה (talk) 17:40, 1 July 2013 (UTC)[reply]

The purpose is to move oxygen into the lungs of the unconscious person, if they are not breathing. --Demiurge1000 (talk) 18:03, 1 July 2013 (UTC)[reply]

I agree with Demiurge1000. The idea of stimulating respiration with CO2 is contradicted by the protocols for more advanced rescuers, who always switch to pure O2 as soon as the equipment can be set up. Jc3s5h (talk) 18:07, 1 July 2013 (UTC)[reply]

Cardiopulmonary resuscitation says: "Current recommendations place emphasis on high-quality chest compressions over artificial respiration; a simplified CPR method involving chest compressions only is recommended for untrained rescuers", confirming what I've been told by people who've been on First Aid courses recently. AndrewWTaylor (talk) 18:14, 1 July 2013 (UTC)[reply]

Does it mean that whwn we put oxigen into the mouth of the unconscious person, and then we compress his chest, the oxigen come in into the blood? מוטיבציה (talk) 18:46, 1 July 2013 (UTC)[reply]

Blood oxygenation doesn't work that way. Oxygen diffuses from the lungs (not mouth) passively (not caused by other actions) into the blood. Circulation just circulates the oxygenated blood to other parts of the body. You might want to read our articles about and breathing and the circulatory system to make sure you understand these basic features. DMacks (talk) 18:54, 1 July 2013 (UTC)[reply]

Of course, maybe I didn't explain myself properly, but it's clear for me the way of the air/oxigen come in into the blood through the lungs, my question was about the CPR specificly.I would like to know if the air we put into the mouth of unconcious person, it's come in into the blood by our combination of the chest compression and breathing. Note, I don't mean about the reserve oxigen in the blood that we move in the body by our compressions, I mean about the NEW air we breath from mouth to mouth or even by oxygen bottle. it means that I would like to know if the mechanical act that we do, makes the same act when the heart work by itself. thank you for the links. מוטיבציה (talk) 20:07, 1 July 2013 (UTC)[reply]

Oxygen gets into the bloodstream through the cell membranes of the alveoli. Mechanically breathing for someone (mouth to mouth resuscitation) is meant to ensure that fresh air gets into the lungs so that oxygenation of the blood can occur. The chest compressions are to do with ensuring blood circulation, not an attempt to squash the lungs to reproduce breathing. If you think about it, you will see that the speed of chest compression is nearer to the speed of the heartbeat than to the pace of breathing. --TammyMoet (talk) 20:38, 1 July 2013 (UTC)[reply]

So, I can understand that you say that the oxygen (of the breating) get into the bloodstream by the time of the CPR. Do I understand well? מוטיבציה (talk) 21:54, 1 July 2013 (UTC)[reply]

You may or may not understand well, but I do not understand you well. If the blood (around the lungs or otherwise) is already well oxygenated "by the time of the CPR" (which appears to mean "before the CPR begins"), then only chest compressions are necessary, and artificial respiration (mouth to mouth) is not.

This is incorrect. Oxygen is still required by the body during chest compressions.217.158.236.14 (talk) 11:13, 2 July 2013 (UTC)[reply]

Or what is it that you mean? The purpose of the artificial respiration (mouth to mouth) is to increase the oxygen concentration in the lungs, with the result that more oxygen is absorbed into the blood around the lungs. The purpose of the chest compressions is to move that blood (and other blood) around the body, including in particular to the brain. --Demiurge1000 (talk) 23:43, 1 July 2013 (UTC)[reply]

Modern first-aid training for the common person uses only chest compressions. The compression of the lungs forces air in and out as well as compresses the heart muscle. 217.158.236.14 (talk) 11:13, 2 July 2013 (UTC)[reply]

^{[citation needed]} If you get proper training (and not just through the Internet, you'll learn to perform mouth-to-mouth. Chest compressions only is only recommeneded for the inept. OsmanRF34 (talk) 18:03, 2 July 2013 (UTC)[reply]

Incorrect, dangerous, and insulting statement - if you get "proper" training, you'll learn to use a ventilation device such as a pocket mask/BVM. No-where recommends mouth to mouth anymore. You'll also learn that for anyone who doesn't do it regularly enough to retain the skill, compression only CPR is recommended, and according to the evidence just as useful (if not more useful) in the hands of a lay responder. So it's not "for the inept", but for the evidence based and competent. Nickopotamus (talk) 3:47 pm, Today (UTC−4)

E 85 (Ethanol vehicles)[edit]

Can an E-85 vehicle be run just on gasoline? 190.140.206.17 (talk) 20:01, 1 July 2013 (UTC)[reply]

Yes. A few points of clarification: E-85 is the fuel, not the vehicle. The vehicle is called a flexible-fuel vehicle, and our article says they run on pure gasoline. Note that whether "normal" cars should use E-85 is contentious, and described at E-85#Corrosion_debate . I am not aware of any production vehicle that is designed to only run on E-85 or ethanol. SemanticMantis (talk) 20:30, 1 July 2013 (UTC)[reply]

E85 means 85% ethanol and 15% gasoline. Once running, most standard internal combustion engines will run just fine on E85...for a while! The problem is that the ethanol is quite corrosive and can dissolve some plastics and rubbers found in seals and hoses. As the percentage of ethanol increases, some cars become harder to start - but most run OK once you do get them started. Flex-fuel vehicles are basically made with the appropriate plastics and metals to resist this corrosion and have engine management computers that handle the startup thing properly.

My 1963 Mini Cooper has rubber parts that even E10 fuel (which is standard in most of the USA) will eventually corrode/dissolve - but modern cars have synthetic materials that protect them at least to that degree.

In Brazil, most people run their cars on 100% ethanol - using a small amount of gasoline in a separate tank just to get the car started. In theory, they shouldn't convert standard vehicles to do that - but they do, and they get away with it - noting that they have to replace some parts more often than they otherwise would - but if you're driving an old junker, the thing will probably die for other reasons long before ethanol corrosion becomes an issue.

SteveBaker (talk) 14:33, 2 July 2013 (UTC)[reply]

You are not quite right about Brazil. Indeed they use flexible-fuel vehicles that run on a combination of gasoline (E20-E25 blend) and hydrous ethanol (E100). OsmanRF34 (talk) 17:52, 2 July 2013 (UTC)[reply]

Also, I believe the air/fuel ratio for ideal combustion is different with gasoline and E85. It may still run at the other ratio, but it won't be very efficient. StuRat (talk) 03:25, 3 July 2013 (UTC)[reply]

Flex fuel vehicles automatically adjust to keep the mixtures correct according to our article. Rmhermen (talk) 03:59, 3 July 2013 (UTC)[reply]

Many older cars is Brazil are not flex-fuel and were specifically designed to run on ethanol. These cars will not run well on gasoline. The main problem is not the difference in air to fuel ratio which can easily be adjusted. The problem is the different compression ratio of ethanol based engines which will lead to engine knocking if gasoline is used. Dauto (talk) 17:54, 4 July 2013 (UTC)[reply]