Wikipedia:Reference desk/Archives/Science/2011 November 16

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November 16

Blood type factor correlation

Are the factors of different blood type systems commonly correlated with the distributions of each others? I mean, for example, is the distribution of blood type Rh+ commonly equal (or different) within the blood types AB, A, B and O? And/Or, still for example, is the distribution of blood type B commonly equal or different within the blood types Rh+ and Rh-? --85.78.106.206 (talk) 02:25, 16 November 2011 (UTC)

Well, we do have the table at Blood_type#ABO_and_Rh_distribution_by_country, which does indicate a correlation, but I'm pretty skeptical of some of the data, so take it with a grain of salt (The U.S. data, for example, shows exactly zero correlation, and the source for it looks like they found separate sources each for ABO distribution and Rh distribution and multiplied them, assuming no correlation. The world average looks like its just a weighted average of all the different sources from different countries they've gotten (of varying degrees of reliability), which highlights why synthesizing sources is not ideal). Both ABO and Rh are highly correlated with ethnicity (Native South Americans, for example, were nearly universally O+ before European contact), so it seems reasonable to suppose that, at least when multiple ethnic groups are represented, there would be some sort of correlation. I believe (but am not an expert) that the mechanisms of inheritance are independent (can someone verify that?), so presumably there would be little correlation between the two within relatively homogeneous groups. Buddy431 (talk) 04:38, 16 November 2011 (UTC)

Agreeing with above, with requested info regarding lack of genetic linkage between ABO and Rh: The ABO locus is on human chromosome 9, whereas RHD, the gene for the major Rh factor, is on human chromosome 1 (NCBI gene entry) along with the RHCE, minor Rh determinant. -- Scray (talk) 14:34, 16 November 2011 (UTC)

Handedness and computer games

Can anyone tell me why I (and I believe most right-handed people) hold the jostick in the left hand and fire with the right, when playing computer games? Surely the joystick is the more complex component, and the fire button the more basic. Furthermore, I would think the joystick is a closer analogue of a ballpoint pen, whereas I'm sure I can hit an elevator button with my left hand, if I try hard enough - firing doesn't look much harder, even if it requires speed. Is there some research saying that fast repetition of a simple task requires more dexterity than slower manipulation of a more complex component? Or perhaps it is historical - in the 80s, when some of us played Galaga and Space Invaders, the joystick was only left-right, which is in fact easy enough (though still close to holding a pen, in a way). Then as things got more complex, we forgot to update our handedness, letting the right take over the task that had become more sophisticated. Am I on to something? It's been emotional (talk) 05:13, 16 November 2011 (UTC)

It depends on the controller system. On the Atari 2600, the fire button was operated with the left hand, and the joystick with the right. Starting with the Nintendo Entertainment System controllers moved away from joysticks and moved towards directional pads. Post-NES systems almost universally place the directional pads under the left thumb, and the fire buttons under the right thumb (c.f. Sega Genesis, Sony Playstation, X-box.) For stand-up Arcade games where handedness matters, I think most are usually oriented to have a joystick operated by one's right hand, but a lot of such systems have duplicate sets of fire buttons to allow the gamer to play either way. I grew up through the Atari 2600 and NES days, so I tend to feel comfortable operating joysticks with my right hand and directional pads with my left; perhaps people who learned to play only directional pads naturally use joysticks with the same hand. It probably doesn't make any real difference in performance; it is ultimately an arbitrary preference which is influenced by what you learned to do. --Jayron32 05:42, 16 November 2011 (UTC)

Now that really takes me back. I think from memory I did play the Atari right-handed, and the photo suggests that was the intended design (though a left-hander could obviously rotate it). I had quite forgotten. It's been emotional (talk) 06:25, 16 November 2011 (UTC)

No, a left-hander would have to rewire the controller to work it left-handed. If you turned it to operate the joystick lefthanded, then "up" becomes "right" and "right" becomes "down" and so on. I suppose a left hander could also rotate their TV set 90 degrees to match the joystick rotation, but that introduces its own set of problems (how does one play sidescrollers like Pitfall that way). No, the standard 2600 joystick was pretty much stuck to one orientation. --Jayron32 06:38, 16 November 2011 (UTC)

No wonder I gave up maths :) I have the spatial intelligence of a two year old, It's been emotional (talk) 09:25, 16 November 2011 (UTC)

When I was a young child I played computer games following the joystick/directions - right; fire buttons - left scheme. When I first encountered those console pads where directions are operated using your left hand I thought exactly what you said: I thought it was counter-intuitive since the side which I considered the most complex should be operated with the right hand. After a very short while, however, I became fully ambidextrous. --Cerlomin (talk) 11:25, 16 November 2011 (UTC)

For many tasks, right-handed people use the left hand to grip and the right hand to perform other operations requiring more complex and fiddly hand movements: e.g. carving meat or wood (knife in right, wood or fork in left); threading a needle; aiming a rifle; holding a plate in your left hand and eating from it with the right. I'm not sure if there's a physiological reason for this that means the left hand is better at holding things and moving them by small amounts to maintain position and the right hand is better at darting in and out. This would match with using the left hand to grip the joystick and the right to do other more mobile tasks like pressing buttons. --Colapeninsula (talk) 15:03, 16 November 2011 (UTC)

In the case of rifle shooting eye dominance is more important than left or right handedness. Alansplodge (talk) 14:43, 17 November 2011 (UTC)

A lot of it comes down to training, the natural "preference" can, especially in young people, be easily modified. Right-handed Canadians and Europeans tend play hockey with a left-handed stick; in the U.S. this is rare. This page describes the phenomenon without explaining it. The best explanation I have heard is that is because Canadians and Europeans tend to learn hockey first, and so are taught to place their "control" hand (the one with better fine control skills) on the top (butt end, farthest from the blade) since if you are going to hold the stick with only one hand, that is how you would do it, and you wouldn't want to have said stick to be controled only with your "off" hand. In America, kids tend to learn "baseball" first, and on a baseball bat your control hand is again on top, but you hold a baseball bat the opposite way from a hockey stick, so "top" is now away from the butt end of the bat. If you take a bat, and move it down like you would use it to play hockey, for American right-handed batters, that puts your hands in the opposite configuration from how Canadians learn to play. This doesn't mean that Americans ultimately play hockey poorly compared to Canadians, the preference is ultimately arbitrary, but Americans are more comfortable holding a hockey stick the same way they were taught to hold a baseball bat. Canadians, who don't have such "priming" when choosing how to hold a hockey stick, have different preferences. This was born out with my wife who (when she was my then girlfriend) I taught to play hockey. She never picked up a baseball bat in her life, and she naturally felt more comfortable with a lefty hockey stick (like many Canadians do) even though she is right-hand dominant. I play hockey with a righty hockey stick, but am also right-hand dominant. --Jayron32 15:19, 16 November 2011 (UTC)

As a point of clarification for my fellow Britons and possibly some other Europeans: when Jayron32 refers above to 'hockey', he/she means what we British call 'ice hockey' (played with a puck on an ice rink), not what we call hockey and he/she would call 'field hockey' (played with a ball on a grass pitch). In the latter only one handedness of stick is permitted by the laws of the game, which is usually held in the same way that a right-handed person usually holds a baseball bat. ('Baseball' is apparently a game resembling our 'rounders' :-) .) {The poster formerly known as 87.81.230.195 90.193.78.50 (talk) 17:04, 16 November 2011 (UTC)

I wonder if there's a difference between how rapidly you can repeatedly press a button between the dominant and non-dominant hand. But I can't think of good search terms to look it up. ;( Wnt (talk) 14:32, 17 November 2011 (UTC)

placing in constellations

ancient Iranians said that periodically sun places in one constellation , such as leo and fish ,.. per one month of year , carefully consider the system , does the sun do so or earth?--Akbarmohammadzade (talk) 05:21, 16 November 2011 (UTC)

That is covered a bit in Sun sign astrology. In such astrological systems, the system is based on the apparent location of the sun at a specific time of day (usually sunrise, IIRC). Thus, if the sun is seen to rise in the constellation "Leo" on the day of your birth, you are said to be born under the sign of Leo. Basically, if you watch where the sunrise happens, you look for the constellation on the horizon where the sunrise occurs. This, of course, has nothing to do with the actual relative motions of the bodies of the solar system, merely the perception of such motion based on the perspective of ancient peoples who made observations based on what they saw. --Jayron32 05:32, 16 November 2011 (UTC)

If the sun is in Leo at sunrise, it's in Leo all day, but it's pretty hard to see Leo once the sun has risen. Imagine a line drawn from the earth to the sun and beyond. It sweeps around the zodiac once per year, spending about a month in each constellation. The constellations of the zodiac are sometimes depicted as forming a ring surrounding the solar system, but that's not physically accurate as the individual stars are at very different distances from the sun. Bobmath (talk) 15:09, 16 November 2011 (UTC)

Actually, it's more accurate to say that sun-sign systems were based on the apparent location of the sun at a specific time of day. Due to precession of the equinoxes, the apparent location of the sun is different from where it was when astrology was first invented. If your star sign is Scorpius, for example, the sun was in Scorpius on your birthday 2000 years ago. On your actual birth date, it was probably in Sagittarius, one constellation off. The ancient Greeks knew about precession and calculated an accurate value for it; I'm not sure why it wasn't incorporated into astrology. --140.180.3.244 (talk) 18:06, 16 November 2011 (UTC)

That's interesting. Is that just for the purpose of saying, "a scorpio is someone born from 23 October to 22 November", or is it also done that way when calculating the detailed charts like File:Astrological_Chart_-_New_Millennium.JPG? Bobmath (talk) 00:41, 17 November 2011 (UTC)

This isn't my area of expertise, but I remember there was once a high-profile publication claiming linkage of the rising sign to something (the one that varies by time of day) as opposed to the usual monthly zodiac sign. I think the whole system is a bit goofy in that the signs are arbitrarily divided into twelve regions which of course never really could match the positions of the constellations, and hasn't been updated for precession of the Earth's axis in some very long time. Wnt (talk) 14:56, 17 November 2011 (UTC)

is it possible to check a diastolic blood pressure without a stethoscope?

is it possible to check a diastolic blood pressure without a stethoscope? (I mean to check a blood pressure with sphygmomanometer but without a stethoscope, or even to check it without a sphygmomanometer if it is possible).109.253.172.135 (talk) 10:02, 16 November 2011 (UTC)

Automatic sphygmomanometers don't require an external stethoscope. Mitch Ames (talk) 11:29, 16 November 2011 (UTC)

it's clear that an Automatic sphygmomanometers don't require an external stethoscope, but I also don't mean about Automatic sphygmomanometers, only about sphygmomanometers that is not automatic. In the past I've heard that it's possible.109.253.172.135 (talk) 12:34, 16 November 2011 (UTC)

As far as I can tell from googling you can guess diastolic from the movement of the needle (although the forum posts I found never seem to go into how) - but it appears that it's just a guess and our blood pressure article states that it's not possible to get a diastolic pressure by palpation. You can get diastolic pressures without a stethoscope or an automatic sphygmomanometer, using a modified sphygmomanometer called a von Recklinghausen oscillotonometer (medical instruments have such wonderful names). From my brief look at this it doesn't look like there are any other "low tech" methods - you can use doppler ultrasound, or arterial pressure transducers, but you specify you are only interested in manual sphygmanomenter based methods. Equisetum (talk | contributions) 14:26, 16 November 2011 (UTC)

IIRC from the last time I was taught this, you watch the "needle" and see when it starts to "jump" or "wiggle" with the person's pulse. When the wiggle starts you have the systolic pressure and when it wiggle stops you have the diastolic pressure. This is, of course, not as good as using a stethoscope, where you can hear the changes in the blood flow, but ultimately the same forces that move the diaphragm on the stethoscope (and which you can thus hear) also affect the blood pressure cuff (and which you can thus "see" on the needle), so in theory you should measure the same thing. --Jayron32 14:36, 16 November 2011 (UTC)

Sounds reasonable - that's basically what the oscillotonometer I mentioned above is doing, but it uses a second cuff to detect the movement of the artery, the placement, pressure and dimensions of which are presumably optimised for detecting the "wiggle". In fact I wouldn't be suprised if Mr von Reckinghausen had the idea for his instrument after observing the effect you are describing. Equisetum (talk | contributions) 18:56, 16 November 2011 (UTC)

Or you can ask the person to tell you when they start feeling their own pulse, and when they stop feeling it. Dauto (talk) 16:03, 16 November 2011 (UTC)

Or, with the pathetic manner in which many healthcare workers screw up both measurement and data entry, just ask the person what his or her blood pressure is. Then, turn around and type something like 1440/90 in the system. Yes, this is something I have to deal with every day. -- kainaw™ 16:06, 16 November 2011 (UTC)

or even 140/90? or was this an ironic demonstration of the pathetic data input method of which you speak :-) Richard Avery (talk) 08:03, 17 November 2011 (UTC)

It was data input. Over 10% of the blood pressures I pull from hundreds of clinics has either SBP or DBP over 500 (which would make "living" rather difficult for the patient). I can't completely fault the nurses though. The medical record system should not allow entries like that. So, the software designers are just as much to blame. -- kainaw™ 13:46, 17 November 2011 (UTC)

What's the English names of these compounds?

Na₃CoO₄

Cs₂CoF₆

K₃CuF₆

KCuO₂

Thanks. --Makecat (talk) 13:36, 16 November 2011 (UTC)

The way naming metal anions works is under IUPAC rules, you take the name of the metal anion and add "ate" to the end, following the "roman numeral" convention for naming the metal. In case 1, the metal bit is cobalt with an oxidation number of 3+, so the anion is called "cobaltate (III)" and thus the compound is "Sodium cobaltate (III)". For non-oxyanions, add the other atoms using the number prefixes (di, tri, tetra, etc.) to the same name. Thus, number 2 is "cesium hexafluorocobaltate (IV)". #3 is thus "potassium hexafluorocuprate (III)" and #4 is "potassium cuprate (III)." Copper does not normally take a 3+ oxidation state, but I think that in these coordination compounds, it can; typing those names into google turns up positive results. this document does a good job explaining how to name compounds like this. --Jayron32 13:54, 16 November 2011 (UTC)

Yup, in the coordination-chemistry world, there are several ways that two oxygens could be other than "–2 ionic equivalent each". The simple ionic analogy is to treat it as (O₂)^2– (one peroxide) rather than (O^2–)₂ (two oxides). DMacks (talk) 20:00, 16 November 2011 (UTC)

Yeah, it would depend very specifically on what the ligands were: Are the ligands oxides, peroxides, or neutral oxygen, and in what combination (there's no rule requiring that every ligand is identical). I think that the basic IUPAC binary naming system ignores this, which is why strange names like "cuprate (III)" show up. My advanced inorganic chemistry class is older than many people who are asking questions here probably are, and having not used much of it in all that time, I would have to defer to someone more knowledgeable to answer what specific ligands are present in the "cuprate (III)" anion, and what the nominal oxidation state of each atom is. --Jayron32 20:07, 16 November 2011 (UTC)

Unless the actual coordinational arrangement is known, the first one is named trisodium cobalt tetraoxide.

The others are named as follows:

• Caesium hexafluoridocobaltate(2-)
• Potassium hexafluoridocuprate(3-)
• Potassium dioxidocuprate(1-)

These names are generated according to the most recent IUPAC recommendations for stoichiuometric, and additive nomenclature.

According to older IUPAC recommendations, the additive names were:

• Caesium hexafluorocobaltate(IV)
• Potassium hexafluorocuprate(III)
• Potassium cuprate(III)

Plasmic Physics (talk) 23:11, 16 November 2011 (UTC)

I suspect that the first compound is sodium peroxidodioxidocobaltate(3-) or sodium peroxodioxocobaltate(III). Plasmic Physics (talk) 23:25, 16 November 2011 (UTC)

Active ingredient - Botox

The active ingredient in Botox is the botulinum toxin, type A. Allergan call it onabotulinumtoxinA (one word), which is obviously just "onabotulinum Toxin [Type] A" stuck together as one word. However, I would like to know what the "ona" part means at the beginning of the word? A Google search isn't very helpful, although it did bring me to various other types of botulinums: "Abobotulinum" or "Rimabotulinum". What does these mean? 86.169.18.74 (talk) 16:31, 16 November 2011 (UTC)

I don't think it actually means anything. Prior to 2009, the nonproprietary name for the drug was "onaclostox", with the "ona-" part being arbitrary and the rest meaning "clostridium toxin". When the drug was renamed in 2009, the "ona" part was carried over; see the AMA statement. Looie496 (talk) 18:56, 16 November 2011 (UTC)

That would be the International Nonproprietary Name. I guess the nonproprietary name page should be a DAB listing that and some pages about "generic names"? DMacks (talk) 19:54, 16 November 2011 (UTC)

Ingredients: Dr Pepper Zero

My question: How much Sweeteners (Aspartame, Acesulfame K, Preservative E211) are in 100ml Dr Pepper Zero? Thanks for help. -- 178.0.148.216 (talk) 16:33, 16 November 2011 (UTC)

My understanding is that manufacturers are not required to give that information, and usually don't. Looie496 (talk) 16:53, 16 November 2011 (UTC)

The exact recipes for products like that are trade secrets. --Tango (talk) 17:45, 16 November 2011 (UTC)

This somewhat loopy blog post is the only thing I could find that gives general amounts of sweeteners for various similar products, which seems to imply that these kinds of products often contain some kind of mix of Aspartame and Acesulfame K totaling 150-190 mg. I've no idea where it gets its numbers from — other Googling shows just a lot of derivative sites — so maybe these are wacko, but as a rough guess it seems not totally unlikely to me, but I know really nothing about this subject. --Mr.98 (talk) 19:43, 16 November 2011 (UTC)

The best way for you to find the answer would be by HPLC using the standard addition method. (I've used it to analyze Coca-Cola once -- I don't think Dr. Pepper would be much different.) Just make sure to remove the gas first, or else the bubbles could clog up the column. 67.169.177.176 (talk) 04:08, 17 November 2011 (UTC)

Help naming the insect

Add caption here

roscoe_x (talk) 19:37, 16 November 2011 (UTC)

Looks like a Woodlouse of some sort, perhaps an Armadillidiidae of some sort (aka pillbug or rolypoly). --Jayron32 19:56, 16 November 2011 (UTC)

My guess is that it's a type of springtail. What it clearly isn't is an insect -- wrong number of legs. Looie496 (talk) 20:07, 16 November 2011 (UTC)

Springtails, like insects, all have 6 legs, so it wouldn't be that if all of those appendages were true legs. Many insects have leglike appendages which are not true legs (modified antenae, mouth parts, etc.) though this could be a type of pill millipede, which isn't an insect. However, pill millipedes aren't usually flat like this, and the legs look a bit wrong (millipedes have two pairs of legs per segment). Rather, maybe this is a type of centipede which closely resembles a woodlouse. --Jayron32 20:17, 16 November 2011 (UTC)

I'm sure that it's a woodlouse, possibly of the genus Porcellio, perhaps Porcellio scaber - it has the right number of segments and appendages and the flatter shape, but there are many many different varieties of woodlice. Mikenorton (talk) 20:30, 16 November 2011 (UTC)

Yep, it's a woodlouse (suborder Oniscidea, which is not an insect). I took a similar photo of another one, some time ago. I don't think it's Porcellio scaber though, as that is a primarily European synanthropic species (though it has been introduced elsewhere). Woodlice have a tendency to look very similar and there really is no way to be sure about the species (genus even) unless you contact a specialist. However, please do specify where the picture was taken from. It's very important if it's ever to be identified. I'm guessing either Indonesia or Taiwan, based on your user page.-- Obsidi♠n Soul 21:03, 16 November 2011 (UTC)

Also @Jayron, it's definitely not Armadillidiidae (pillbugs). Pillbugs are woodlice, but unlike other woodlice, they are very distinctive in that when they curl up, they form a perfect sphere that completely protects their legs and undersides. One easy way to tell a pillbug from other woodlice is that their fronts and backs are hemispherical and the uropods (the twin "tails") are rounded and actually meld in with the margin (i.e. they don't protrude like you can see in the specimen in the picture).-- Obsidi♠n Soul 21:13, 16 November 2011 (UTC)

Google-image [woodlouse] turns up lots of pics, including the second one on this page,[1] which looks nearly identical to the critter in this section. No species name given, unfortunately. The author of the article states that the woodlouse is actually a type of crustacean. My first thought upon seeing the picture was that it looked kind of like a trilobite. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:46, 17 November 2011 (UTC)

It's definitely a woodlouse, and definitely not Armadillidiidae. Porcellio scaber isn't native to Taiwan, and also doesn't look quite like that. There are more than 3,500 species of woodlice worldwide. --Stemonitis (talk) 11:53, 17 November 2011 (UTC)

Tunneling + Superluminal neutrino?

I was just in class today and I was told that quantum tunneling was a phenomenon in which a particle went through a barrier due to the fundamental indeterminacy of the quantum world. Now I was wondering: Isn't the speed of light a barrier? couldn't that be a possible explanation for the superluminal neutrino found about a month ago?157.253.197.73 (talk) 21:04, 16 November 2011 (UTC)

The speed of light is not a "barrier" except in a philosophical sense. Quantum tunnelling refers to a very specific process; the "barrier" being surmounted is a potential energy barrier; that is a particle is able to transverse two states which would be impossible under classical physics understanding. It is the quantum mechanical equivalent of a person walking through a wall unscathed, and leaving no mark on the wall. --Jayron32 21:10, 16 November 2011 (UTC)