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February 23

Updates on Desert Varnish?

Is Desert Varnish alive? I haven't seen any updates. If this is considered alive will this mean that the shadow biosphere is more probable? 199.19.248.47 (talk) 02:13, 23 February 2016 (UTC)

That would depend on whether the microbes in the desert varnish are similar to known microbes. StuRat (talk) 03:17, 23 February 2016 (UTC)

As I understand it, there are few if any detected bacteria or other 'normal' lifeforms in the varnish. The huge question is whether there is any other kind of highly atypical life living in there and responsible for the otherwise-hard-to-explain chemistry of the varnish. So, the idea occasionally shows up that there might perhaps be some completely different forms of life in there. Stuff that's maybe not DNA or even RNA-based. Such a thing would go a long way to explaining the unlikelyhood that abiogenesis seems to have happened only once...by proving that it actually happened more than once. If that were found to be the case, then the conclusion would have to be that life would always form with near 100% probability in any suitable environment - and from that we would extrapolate that there is life everywhere in the universe - and from that we get into the Fermi Paradox and the Great Filter - and from that we can deduce that humanity is doomed to be wiped out within a couple of generations as all other intelligent life in the universe evidently has been. Big BIG conclusions would likely emerge from the discovery that there is some kind of non-DNA/non-RNA life living there.

But we haven't found it yet. I presume scientists have looked there - but detecting that life exists, based on unknown chemistry - and evidently being very, very slow lived - would be exceedingly difficult. On the other hand, we don't have an alternative explanation for the varnishes' peculiar chemistry - and an exotic lifeform would be a possible explanation for that.

So - conclusion so far? We don't know.

SteveBaker (talk) 03:42, 23 February 2016 (UTC)

Quoting from "Biogeological Analysis of Desert Varnish Using Portable Raman Spectrometers" published in Astrobiology (journal):

Desert varnish, also known as rock varnish or desert patina, is a thin skin (often only microns in thickness) comprising iron(III) oxides, manganese(IV) oxides, and clays on the outer surfaces of rocks located in either hot or cold desert environments (Potter and Rossman, 1979). The first suggestions that desert varnish might have a biological origin were made independently by White and Laudermilk (White, 1924; Laudermilk, 1931), both of whom postulated that botryoidal nucleation could arise from epilithic manganese-oxidizing bacteria, fungi, and algae in desert conditions. This was later confirmed by Krumbein and Jens (1981) and by Dorn and Oberlander (1981). A comparison of desert varnish morphologies (containing biomineralized manganese oxides) with microstromatolites was performed by Raymond et al. (1992), and the incorporation of biomineralized silica by bacterial colonies was reported by Westall et al. (1995).

Indeed, one study even found manganese oxidizing bacteria in desert varnish [1], and that's from 1981. There are also various spectroscopic studies easily found on pubmed that find common metabolic products in desert varnish. I think at this point the evidence is extremely compelling that at least some desert varnishes are of organic nature, and the causative organisms are no more unusual than other extremophiles. There is a possibility that some desert varnishes do not arise in the same fashion, but at this point I would take Occam's Razor and assume they're all caused by normal life forms. Someguy1221 (talk) 09:00, 23 February 2016 (UTC)

For example, the extremophile life by a black smoker is quite strange. StuRat (talk) 14:35, 23 February 2016 (UTC)

This [2] is a student paper on the topic, but it seems to cover most of the bases nicely, and has a bibliography that includes both many recent studies and some of the older key works. SemanticMantis (talk) 17:08, 23 February 2016 (UTC)

Awesome - I've updated my response. SteveBaker (talk) 17:13, 23 February 2016 (UTC)

Interesting question! This looks like a good source if the Google Copyright Gods smile on you. More generally, the thing that gets me is the statement going back to this paper that desert varnish is nucleated. What I haven't seen is whether there is any useful genetics to this nucleation. Can you create nuclei of different morphologies of varnish (lamellar, botryoidal I think were examples given) and have the regions grow up that way? If so, then the varnish would seem to have genetics. But I didn't see reference to such an experiment. (A pity ... you'd think it would be a money-maker for construction and other stoneworking to select out forms that would have desirable properties, e.g. transparency, and to pretreat stone surfaces with them) Wnt (talk) 17:53, 23 February 2016 (UTC)

It's definitely interesting - but not just for practical applications. If we could show that there exists life here on earth that shares no evolutionary history with life-as-we-know-it - then...

• We'd know that abiogenesis is a commonplace thing.
  • Which implies that the numbers in the Drake equation change drastically in favor of more life elsewhere in the universe.
    • Which lends teeth to the Fermi paradox.
      • Which means that the Great Filter is alarmingly real.
        • Which means that humanity is almost certainly doomed to near-extinction within a handful of generations.

Better hope it's not there. SteveBaker (talk) 16:14, 25 February 2016 (UTC)

This really isn't that obvious to me. We see all sorts of "life" that has a 1-bit genetic code - fire, salt crystallization, that kind of stuff. If it counts, prions are sort of more than that - I remember there's an apparent difference between kuru and Creutzfeld-Jakob disease, AFAIR, said to be based on some mysterious variation in what misconformations of the protein are possible. (I haven't checked that story lately, could be wrong!) It's at least conceivable that there could be several kinds of "life" with ten bits of genetic code on the average planet, that were incapable of progressing further, while biological life is preposterously unlikely. (But no, I think there's a Great Filter ... at least, if you're using the term right, from the article I get a different gloss. I mean, how long can you live with nuclear weapons pointed at you and not think...) Wnt (talk) 02:20, 27 February 2016 (UTC)

Rorschach's mask

Kovacs Rorschach.png - Rorschach with and without his mask

A fictional character called Rorschach has a mask that is described as follows:

Rorschach's mask, which he considers his true "face", is a part of fabric made from a material derived from the technologies of Dr. Manhattan, and it is blank except from the front, where two viscous liquids, one black and one white, are between two layers of latex. The liquids continually shift in response to heat and pressure, which explains why the liquid only animates when Rorschach puts it on his face. The black liquids form symmetrical patterns like those of a Rorschach inkblot test while never mixing with the white color of the mask, thus never producing a gray color, much like Rorschach's view of morality and the world.

— Rorschach (comics)

Would it be possible to create something like that in real life? How? The restriction on non-symmetrical patterns can be ignored.

The Quixotic Potato (talk) 18:44, 23 February 2016 (UTC)

Sure, if you're willing to ignore the symmetry. Miscibility gives some information on when liquids do mix. When you have two or more liquids that won't mix, you call it a Multiphasic_liquid. A common example is Vinaigrette. Emulsion is what would happen if Rorschach slept on a vibrating bed or otherwise was subjected to long-term agitation, though often emulsions will settle out and unmix if given enough time. Here's eight minutes of slow-motion video showing a multiphasic mix of water, oil and milk [3] that illustrates the immiscibility of oil and water. SemanticMantis (talk) 19:21, 23 February 2016 (UTC)

Also, there are temperature-sensitive liquid crystal applications. See, for example Liquid crystal thermometer. Something like that could be impregnated in the mask, and could perhaps produce the desired results. --Jayron32 19:34, 23 February 2016 (UTC)

It should be quite easy to achieve this effect with help of the upcomming OLED-technology, including building advanced masks with it. Certainly much more impressive stuff even like personifying other people. You can find this in nature too. Cameleons, octopuses and squids have brought this beyond perfection including surface changes and using this to hypnotize prey youtube sample. It should be possible to build something alike a squid skin with technology but you will need a Billionair to pay the bills. --Kharon (talk) 21:14, 23 February 2016 (UTC)

To clarify, I think it will be hard to make an actual mask that looks cool and "works" like the one described. But milk, motor oil and clingfilm should illustrate that the concept works just fine, even with cheap, easily accessible materials. SemanticMantis (talk) 21:40, 23 February 2016 (UTC)

In concept, this is essentially a lava lamp. Making one work in 2D is a bit demanding in that both liquids have to wet the containing surfaces equally well, I think. In a stereotypical lava lamp, the wax balls are permitted to totally avoid contact with the containing surface, but if the liquids are very black and very white, that would make the visible surface all one color, or at least tinged with it. Wnt (talk) 21:53, 23 February 2016 (UTC)

I think current EPaper solutions would work here too. They have the advantage of being flexible and reacting to sunlight appropriately - it would also make getting the symmetry to work easy. But if you truly want the mixing of fluids per the description of how it works, kinda like a 2D lava-lamp - then that's harder - and if it has to react to the skin beneath and stay symmetrical - then I think it's impossible without electronics. SteveBaker (talk) 16:05, 25 February 2016 (UTC)

I love the Reference desk. Thanks everyone, very interesting answers! I will have to do some research. The Quixotic Potato (talk) 16:56, 27 February 2016 (UTC)

February 24

How does smoking affect cognitive abilities?

Nootropic#Stimulants is the only evidence of a positive effect of smoking on cognition I could find. I wonder whether long-term smoking has long-term negative effects on (any) cognitive abilities. Could it be that smokers perform better after smoking, but just because that reduces abstinence signs? --Scicurious (talk) 00:42, 24 February 2016 (UTC)

Well, smoking may lead to loss of concentration due to distraction. That is, smokers spend time thinking about where to get cigarettes, when they can get a smoke break, where they can go to smoke, if they stink of smoke, etc. Then, if they get a smoker's cough or a far worse medical problem, that's even more distraction. StuRat (talk) 01:11, 24 February 2016 (UTC)

DO you have any references for any of that, or are you just making it up as you go along, as usual? --Jayron32 01:17, 24 February 2016 (UTC)

If you would read the link I provided, you can see the well established link between smoking and COPD. Do you imagine that having COPD, lung cancer, etc., is not mentally distracting ? But then I suspect you don't really care about that and are just trying to make trouble, as usual. StuRat (talk) 02:26, 24 February 2016 (UTC)

Having worked with many smokers in my time, I fully agree with your assessment. Keep in mind that they are addicts, and addicts are always focused on the next fix. Even forgetting the physiological disasters connected with smoking, it means they are always looking for breaks to go outside to the smoking areas, thus undermining both their own and their colleagues' productivity. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:53, 24 February 2016 (UTC)

The OP did not ask about the effect of smoking on lungs, i.e. COPD. The OP asked about evidence regarding connection between smoking and cognition. --Jayron32 02:30, 24 February 2016 (UTC)

And I ask again: "Do you imagine that having COPD, lung cancer, etc., is not mentally distracting ?" StuRat (talk) 05:58, 24 February 2016 (UTC)

What I imagine is irrelevant to this desk. This is not the imagination desk. It is the reference desk. --Jayron32 11:22, 24 February 2016 (UTC)

You're just trying to make trouble again, and I'm not going to provide a source to prove that having lung cancer or COPD can be mentally distracting, any more than I would provide a source to prove that 1 + 1 = 2. StuRat (talk) 00:56, 25 February 2016 (UTC)

Let's put this a different way. If someone asks how does sexual intercourse affect cognitive abilities, it's fairly unlikely the answer they're looking for is you may get HIV and if you do, it's going to be mentally distracting. Nil Einne (talk) 06:16, 24 February 2016 (UTC)

Well, early sexual activity does correlate with poor academic performance, pregnancy, dropping out, lower average wage, etc. Then there is the risk of various diseases, too. Those would certainly be worth mentioning. Perhaps not the main intent of the Q, but related. StuRat (talk) 06:24, 24 February 2016 (UTC)

Sure and people could get so frustrated with dumb answers that they'll ban someone from the RD and that person will be so unable to stand not being able to give random junk answers that they'll take their own life. An unfortunate outcome, but it doesn't mean suicide is a good answer to the question, how does using the RD affect your life. Nil Einne (talk) 06:34, 24 February 2016 (UTC)

• There are several good references here the OP may be interested in. --Jayron32 01:19, 24 February 2016 (UTC)

I agree with Jayron32. Suggesting that someone with a smoking related illness has impaired cognitive ability due to being distracted is Sturat "making it up as he goes along. ;) Vespine (talk) 02:56, 24 February 2016 (UTC)

No, StuRat is right. The addict's primary mental focus is on their next fix. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:02, 24 February 2016 (UTC)

That's complete nonsense, I disagree entirely. I was a smoker for 15 years and very very rarely was i distracted by "where I'm going to get my next fix", maybe during times of unusual stress, and EVEN THEN i would dispute that my cognitive ability was impaired in any measurable way. Clearly personal anecdote is not a reliable reference, but then neither are any of the claims you've proposed. Vespine (talk) 03:36, 24 February 2016 (UTC)

The addict also is typically in denial. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:51, 24 February 2016 (UTC)

For every complex problem there is an answer that is clear, simple, and wrong. Vespine (talk) 04:15, 24 February 2016 (UTC)

Please stop being so ridiculous, the CLAIM you are attempting to defend is that smokers are cognitively impaired due to their "addiction". If that was even REMOTELY true, it should be fairly easy for you to find some references supporting that claim, instead of attempting witty rejoinders. Vespine (talk) 04:29, 24 February 2016 (UTC)

Who should I believe? You? Or my own eyes? ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:00, 24 February 2016 (UTC)

The plural of anecdote isn't data. Fgf10 (talk) 08:08, 24 February 2016 (UTC)

You do realize that is actually the whole point of science? Because you can't always believe your own eyes. From homeopathy to exorcism, countless people believe complete nonsense because they trust their own eyes over empirical evidence gathered by other people. Vespine (talk) 05:25, 24 February 2016 (UTC)

There are many types of addiction, Mr B Bugs. Such as, for example, the addiction to only ever making unreferenced, anecdotal comments on a reference desk. The "undermining of productivity" and other damage that those sorts of "contributions", and their aftermath, make, would be hard to overestimate. I take the charitable view and assume that such posts are usually not made maliciously, but under the influence of illicit substances (another addiction). -- Jack of Oz ^{[pleasantries]} 06:12, 24 February 2016 (UTC)

The loss of productivity by smokers is a frequent problem in the business world. How many smokers have you worked with in your career? ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:43, 24 February 2016 (UTC)

Do you have a reference for that? DuncanHill (talk) 09:45, 24 February 2016 (UTC)

Here's a survey from a few years ago,[4] discussing the loss of workplace productivity caused by smokers. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:46, 24 February 2016 (UTC)

Which manages to misname the journal Lundborg was published in. DuncanHill (talk) 09:59, 24 February 2016 (UTC)

Wow, a typo invalidate the whole thing, eh? Never mind that the report squares with what business colleagues have been saying for a long time. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:01, 24 February 2016 (UTC)

• Let's actually use some references shall we? Rather than listen to Baseball Bugs spouting baseless nonsense as per usual. Let's start here, for instance (just the first sensible hit in a quick journal search): " In nonsmokers and nondeprived smokers, nicotine enhances finger tapping, focused and sustained attention, recognition memory, and reasoning." Fgf10 (talk) 08:08, 24 February 2016 (UTC)
  • Addicts often think their performance is enhanced by the drug. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:23, 24 February 2016 (UTC)

And their thoughts change metrics in objective tests? Save yourself the embarrassment and just stop posting on this question. Fgf10 (talk) 10:08, 24 February 2016 (UTC)

During those tests, how often did they take smoke breaks? Save yourself the embarrassment and concede that I'm right and you're wrong. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:13, 24 February 2016 (UTC)

• • • Do you have a reference for that? DuncanHill (talk) 09:45, 24 February 2016 (UTC)
      • You may find this[5] enlightening. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:49, 24 February 2016 (UTC)
        • Ideally not a commercial site trying to drum up business for itself. DuncanHill (talk) 09:51, 24 February 2016 (UTC)
          • Feel free to look for a source that would be acceptable to your exacting standards. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:53, 24 February 2016 (UTC)
            • You made the assertion, you are responsible for finding a reliable source. Try reading WP:RS. DuncanHill (talk) 10:01, 24 February 2016 (UTC)
              • The source is good enough, whether you believe its information or not. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:03, 24 February 2016 (UTC)
                • Bugs, an advert is not a reliable source. You know that perfectly well. DuncanHill (talk) 10:05, 24 February 2016 (UTC)
                • The source is absolute bullshit. Again, just stop it. Fgf10 (talk) 10:08, 24 February 2016 (UTC)
                  • It restates conventional wisdom, so it's good enough. FYI, as regards you two, I put up with a lot more personal attacks from the likes of you two than I should have to be expected to, but luckily I have too little regard for your vile and vulgar comments to bother doing anything about it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:11, 24 February 2016 (UTC)

It completely contradicts the numerous peer reviewed scientific papers cited here already. Do you really not understand the difference between scientific studies and adverts and hearsay? Shocker: sometimes conventional wisdom is wrong. Good thing we all don't have your attitude, or we'd still be rubbing two stick together. Fgf10 (talk) 10:15, 24 February 2016 (UTC)

Feel free to provide a source that asserts addiction improves job performance. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:17, 24 February 2016 (UTC)

You're the one that brought up job performance. My sources adequately answered the OPs question. Your unsourced assertions are irrelevant to the question. Fgf10 (talk) 10:21, 24 February 2016 (UTC)

Of course they're more focused - they're thinking about their next nicotine fix. Have you never worked with smokers before? ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:23, 24 February 2016 (UTC)

Neither of our personal experiences are reliable sources. Again, provide reliable sources for your assertions. Fgf10 (talk) 10:25, 24 February 2016 (UTC)

Answer the question. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:27, 24 February 2016 (UTC)

Say the magic word! Of course I have worked with smokers, and have never seen a problem in their job performance. Again, that is irrelevant. Provide reliable sources for your assertions, or accept that you are wrong. Fgf10 (talk) 10:28, 24 February 2016 (UTC)

In this writeup,[6] nicotine enhances cognitive skills, but deprivation of nicotine degrades performance. As you would expect for an addictive substance. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:36, 24 February 2016 (UTC)

There we go! That wasn't that hard now, was it? PNAS even, good source. Completely agree with you. See how easy life becomes when you actually have sources to back up your assumptions? Fgf10 (talk) 10:39, 24 February 2016 (UTC)

I went to PubMed and typed in smoking cognitive decline (seriously not rocket science!) and found this study, which says in its introduction "Epidemiological studies have been conducted to explore the associations between smoking and physical and cognitive capability in mid to later life, generally concluding that smoking is associated with worse capability outcomes.1–8" I didn't look at everything that came up, but this is how you get started answering this kind of question. Wnt (talk) 12:30, 24 February 2016 (UTC)

I am very certain that some weeks ago, I read and linked to an Army or Air Force Federal Aviation Administration research paper, hosted on Defense Technical Information Library, about the effects of oxygen deprivation on standardized testing performance; and one of the strongest factors in that specific experiment was whether the participants smoked tobacco cigarettes.

After just a few moments searching our archives: in January of this year, I wrote: "Here is a wonderful piece of quantitative psychometric research: Effects of Hypoxia... (1997), in which test subjects performed the MATB test battery with different oxygen levels. Amazingly, being a smoker has an incredible negative effect on your ability to focus - perhaps stronger than the effect of hypoxic hypoxia!"

Nimur (talk) 15:10, 24 February 2016 (UTC)

Flower from a film poster

• Hi. I'm currently writing a paper about symbolism in Indonesian film posters, but I'm having trouble ID-ing the flowers in this one (I've also seen this poster with the flower looking yellow). The image used was almost certainly taken in Indonesia, and my wife says she's familiar with the plant, but doesn't know its name. Does anyone have an idea as to what kind of plant it is? — Chris Woodrich (talk) 07:20, 24 February 2016 (UTC)

Hi Chris. Are you sure it is a flower in that poster? It looks more like the lady is holding a bunch of grain seed heads to me. Perhaps she is harvesting millet or some other cereal grain? SemanticMantis (talk) 14:34, 24 February 2016 (UTC)

• It's a possibility, yes. I'm far from a botanist (as evidenced by my frequent visits here). Isn't Dipsacus also possibility? — Chris Woodrich (talk) 16:11, 25 February 2016 (UTC)

I suppose so, though to me the heads of teasel look bigger and closer to spherical than those in the photo. I'm not sure that teasel would have been grown in any quantity in Indonesia, but I also don't know much about agriculture in Indonesia. That's where I'd start - forget the giant list of plants found in Indonesia, and focus on the plants grown at large scale in Indonesia. I could be wrong but I think this is a harvest photo, and so I'd try to make the most of that clue. SemanticMantis (talk) 15:13, 26 February 2016 (UTC)

How do epidemiologists track down the source of a sexually transmitted disease if clinics have anonymous testing?

What is actually anonymous in anonymous testing? And if it's really anonymous, does that mean epidemiologists won't be provided information about the patient's sexual history? 140.254.70.33 (talk) 12:48, 24 February 2016 (UTC)

Different jurisdictions have different rules regarding the confidentiality of Medical records. In the United States, who may have access to those records may be governed by various laws, for example the Health Insurance Portability and Accountability Act or HIPAA. --Jayron32 12:55, 24 February 2016 (UTC)

See: http://www.cdc.gov/amd/project-summaries/tracking-std-transmission.html where it says:

CDC scientists are using genetic information (sequence data, including next generation sequencing) for the viruses and bacteria that cause these diseases, together with demographic, geographic, and clinical data from infected persons—such as risk group, age, location, and health status—to understand more about how infected people are connected. Combined, this information helps scientists to identify more precisely how these diseases are spreading so that outbreaks can be stopped.

Richerman (talk) 15:02, 24 February 2016 (UTC)

How does glucagon avoid peristaltic?

As a preparation for ERCP test, the patient is given glucagon in order to avoid the peristaltic action. I would like to understand how an hormone that its function is to save on glucose level in the blood (by secreting glucose from the liver), also avoid peristaltic? ThePupil17 (talk) 14:11, 24 February 2016 (UTC)

See Glucagon#Endoscopic_retrograde_cholangiopancreatography. Ruslik_Zero 19:33, 24 February 2016 (UTC)

Distinguishing Human Blood from Pig Blood by taste/other easy characteristics...

This is sparked by the most recent episode of Lucifer (TV series). How difficult would it be to identify Human Blood vs. Pig Blood (or other mammalian species) by either taste or another human sense (Touch(?), Sight(?)). Also given that Lucifer was able to identify it as not only not Human but specifically as Pig, how easy would it be to tell enough species apart to specifically identify it as Pig? I'm guessing this would essentially be a Supernatural power since my guess is that even with a standard visible light microscope telling the species of blood simply identified as Mammalian would be difficult. Ideas?Naraht (talk) 14:21, 24 February 2016 (UTC)

Forensic use of genome profiling method to differentiate human blood samples from rat, squirrel, cat, dog, cow, and antelope. AllBestFaith (talk) 15:03, 24 February 2016 (UTC)

Interesting. This indicates to me that my guess as to the level of science to be *sure* is about right. I'm assuming that the pig is approximately the same genetic distance from humans as the animals mentioned in the article. Still doesn't answer the original question. :)Naraht (talk) 16:27, 24 February 2016 (UTC)

Pigs can have type A or type O blood; organs from pigs identified as blood group O cause less immune rejection when transplanted to humans.[7] AllBestFaith (talk) 16:40, 24 February 2016 (UTC)

Less rather than none, I would presume that if a pig with type O was able to donate to humans that blood donation today would be vastly different.Naraht (talk) 18:45, 24 February 2016 (UTC)

Here's some person [8] sharing their opinions on the tastes of different bloods. I don't think it's too crazy to think that some experienced people could easily tell e.g. pig blood from cow blood by taste alone. Keep in mind people regularly claim to detect differences in the same grapes grown in different places (Terroir), and I think most all of us can distinguish pig meat from cow meat by taste alone. SemanticMantis (talk) 17:30, 24 February 2016 (UTC)

Also, the character in Lucifer is the devil himself, and thus may be assumed to have abilities that humans lack. --Guy Macon (talk) 18:20, 24 February 2016 (UTC)

Not surprised the Chicken is different, which is why I specified Mammalia. Yeah, I can see someone with a wine taster's palate possibly able to do this. And yes, he's the Devil, but there is a difference between truly Supernatural abilities and those which simply come with a lot of experience (elsewhere in the episode, he comments on what bone is being broken *just by sound* in an attack of another character on the members of a gang. Supernatural or just what a Connoisseur of torture would learn over a few millenia, unclear.)Naraht (talk) 18:45, 24 February 2016 (UTC)

In forensic science, they generally use the Kastle–Meyer test to confirm that there is hemoglobin present - and if there is, they do an Ouchterlony double immunodiffusion to prove that it's human in origin. That second test takes 48 hours and relies on antibody/antigen bonding. Since those kinds of determination at crime scenes are typically kinda urgent, I'd guess that if there was an easier way to identify blood as human, they'd probably be using it. SteveBaker (talk) 21:40, 24 February 2016 (UTC)

To be fair, it's possible that "just taste it!" never actually occurred to them. --Trovatore (talk) 21:43, 24 February 2016 (UTC)

Rather than looking at this from a forensics standpoint, I wonder if consulting a farmer or butcher would be more helpful. Most of the material that leaks from meat by the time it gets to the butcher will be protein rich liquid rather than actual "blood", but it would make for an interesting data point. The guy at the slaughterhouse would nominally be more informed about differences in blood, but I'm not sure how common it is for slaughterhouses to regularly manage more than one kind of animal. Just a thought. Matt Deres (talk) 15:25, 25 February 2016 (UTC)

In this particular case, it was at a "Crime scene" where the pig had been killed on the other side of a screen, and Lucifer was tasting the blood that had run under the screen. So Blood, not "meat juices".Naraht (talk) 15:32, 25 February 2016 (UTC)

Comparing the taste of my own blood from a cut finger to the blood from a really rather good rare steak last night...I can't tell the difference. (OK - cow not pig - and anecdote != evidence) SteveBaker (talk) 15:35, 25 February 2016 (UTC)

The Ouchterlony test is indeed a method, but it's a very old method. I was expecting there'd be something comparable to a pregnancy test that could do it, and found this (in case the links die, this brand is the "ABACard Hematrace") (see photo here). Wnt (talk) 13:39, 26 February 2016 (UTC)

See Lowenstein et al, Forensic Sci Int. 2006. Identification of animal species by protein radioimmunoassay of bone fragments and bloodstained stone tools. PMID 16191470. --NorwegianBlue ^talk

Is there a source for the number of the types cells organalles in human cell?

I'm looking for a source that site the exactly number of the cell organelle and the number of the cell parts. Yes, I know that there are many types of cells, but there are a basic number of general organelle that found in all human cells.ThePupil17 (talk) 14:36, 24 February 2016 (UTC)

"There are a basic number of general organelle that found in all human cells." -- Really? I don't see any information about organelles inside human red blood cells. Our article says "They lack a cell nucleus and most organelles", and "In mammals, erythrocytes also lose all other cellular organelles."

Now, I think it probably is true that there is a list of organelles that most types of human cells have. But then you have to get careful about which types of cells count in order to get a precise answer. Our article at organelle gives just seven organelles as the "major" organelles of eukaryotes. If you're interested in organelles, I'll also recommend symbiogenesis. SemanticMantis (talk) 15:12, 24 February 2016 (UTC)

Thank you for your comment. I knew that RBC are exception (and originally they do have). Do you know another type of human cell like RBC? ThePupil17 (talk) 16:07, 24 February 2016 (UTC)

Also worth noting is that the exact classification scheme is somewhat arbitrary and will vary depending on agreed upon conventions. Defining what makes a bit of a cell an organelle, or a part of an organelle, and how to classify all those bits, is not a universal truth given by God. These are human created schemes created by humans for our own purposes, and given the arbitrary nature of all such schemes, there are going to be differences. --Jayron32 16:19, 24 February 2016 (UTC)

It turns out mature Lens_(anatomy)#Lens_fibers also have no nucleus or organelles [9]. Also "Corneocytes are keratinocytes that have completed their differentiation program and have lost their nucleus and cytoplasmic organelles." So by mass we have a decent amount of non-nucleated cells, but only a few types. Gut flora have lots of cells without nucleus or membrane-bound organelles, but we don't usually consider those cells "human". SemanticMantis (talk) 17:01, 24 February 2016 (UTC)

Also, the definition of organelle is a bit fuzzy. Our article states that organelles usually are separated by a lipid bilayer, but lists "organelles" that are not. Both the nucleus and the cytoplasm contain many subcompartments which separate biochemical processes into confined spaces. The organelle article lists the proteasome among the organelles, the Cajal body is classified as a sub-organelle in its article. Where to draw the line is rather arbitrary, IMO. --NorwegianBlue ^talk 22:34, 27 February 2016 (UTC)

Is there any nervous system in the heart?

Is there any nervous system in the heart? For example, if we can to reach to the heart of creature while it alive and awake (without anesthesia or analgesia) and make a incision, is it supposed to heart it? ThePupil17 (talk) 17:26, 24 February 2016 (UTC)

See Angina pectoris. Key quote: "This is explained by the concept of referred pain, and is due to the fact that the spinal level that receives visceral sensation from the heart simultaneously receives cutaneous sensation from parts of the skin specified by that spinal nerve's dermatome, without an ability to discriminate the two." --Guy Macon (talk) 18:28, 24 February 2016 (UTC)

The question being asked here is actually whether heart tissue contains pain receptors, and the answer, as Guy says, is that it does. (Brain tissue, as you might know, does not.) Looie496 (talk) 18:33, 24 February 2016 (UTC)

What does it mean "pain receptors"? ThePupil17 (talk) 00:31, 25 February 2016 (UTC)

See pain receptor. StuRat (talk) 23:38, 27 February 2016 (UTC)

I didn't quite understand the example of the question. Anyway, there are motor nerves and sensory nerves, and the answers so far have only dealt with the latter. The heart does not have motor nerves in the conventional sense, but it has nerves which influence its motor activity. See Sinoatrial node and next Heart rate. Note the figure which shows innervation from the vagus nerve and the sympathetic nerves. Then read about the electrical conduction system of the heart, which is made up of specialized muscle cells which function in a similar way to nerve cells. A denervated heart does not stop to beat, but it has a limited ability to respond to the physiological needs of the body by changing its pulse rate, responding only to soluble mediators in the blood stream. --NorwegianBlue ^talk 22:11, 27 February 2016 (UTC)

Koala is a marsupial

When was it first revealed that the koala is a marsupial?? I know that the koala was initially thought to be a bear species when it was discovered by Europeans in 1788. Georgia guy (talk) 22:56, 24 February 2016 (UTC)

According to our article (see: Koala#History) "English naturalist George Robert Waterhouse, curator of the Zoological Society of London, was the first to correctly classify the koala as a marsupial in the 1840s. He identified similarities between it and its fossil relatives Diprotodon and Nototherium, which had been discovered just a few years before". Richerman (talk) 23:05, 24 February 2016 (UTC)

Also interesting to note: "The first published image of the koala appeared in George Perry's (1810) natural history work Arcana. Perry called it the "New Holland Sloth" on account of its perceived similarities to the Central and South American tree-living mammals of genus Bradypus" Richerman (talk) 23:15, 24 February 2016 (UTC)

It is now known that there are no truly native species of placental mammals in Australia. At the time of the so-called discovery of Australia by Europeans, there were two species of placental mammal in Australia, a canid, and a hominid. The dingo is sometimes referred to as a "wild dog of Australia". He is not that. How did he get there? No one has suggested that the dingo swam across Wallace's Line. How did the hominid get there? Boats. If the dingo came in boats, he is not a wild dog of Australia. He is a feral dog of Australia. He came in the boats of the Australians. Robert McClenon (talk) 03:51, 25 February 2016 (UTC)

If you read Dingo#Origin and genetic status we still don't really know how or when the dingo got to Australia. If it has been there for over 20,000 years, as is indicated by Aboriginal rock art, I think it would be fair to call it wild rather than feral. Richerman (talk) 08:18, 25 February 2016 (UTC)

Aren't you forgetting that bats and rodents are also native to Australia? See Mammals of Australia#Placental mammals. - Lindert (talk) 09:50, 25 February 2016 (UTC)

An interesting but only marginally related comment has to do with the taxonomic status of the opossum, in particular the Virginia opossum. Linnaeus didn't know what to do with it, because, prior to the exploration of Australia, he didn't know what is was. At the time, it was not only ordinis sui, but subclassis sui. When Australia was explored, it was then discovered that the opossum belonged to a previously unknown subclass. It took a long strange journey from Africa to North America, and the ship on which it took its journey was nothing less than South America itself, which took a long strange journey from Africa to North America. Robert McClenon (talk) 03:51, 25 February 2016 (UTC)

Africa had nothing to do with it. Marsupalia originated in South America, when Australia and South America were still attached to Antarctica. Africa was separate by then. The marsupials of Australia got there from South America via Antarctica, according to current theories. It is logically possible marsupials originated in Antarctica, but we have no such advice, and the diversity of and most primitive forms of marsupials live in the Americas. See monito del monte. μηδείς (talk) 02:14, 27 February 2016 (UTC)

February 25

Where does the air go on a hot day?

On a hot day, the air gets thinner; less atoms per unit volume. I'm gonna go out on a limb here and say that atoms are not created or destroyed in the earth's atmosphere in sufficient numbers to make up the difference; where do they go, then? Does it follow the sun? Is this what meteorologists mean when they refer to "high pressure/low pressure" fronts; warm weather in one area pushing atoms out over hundreds of miles, or cold weather "sucking" them in? Do they "go" up (e.g., does the air density at 10km vary with the temperature at ground level? That seems somewhat hard to believe)? Apologies for the silly title, by the way! Riffraffselbow (talk) (contribs) 00:56, 25 February 2016 (UTC)

In a pinch yes, warm air has less atoms per unit volume BUT the volume is increased, the number of atoms stays the same, warm air expands, becomes less dense and "floats up" sucking in surrounding, often cooler air. Vespine (talk) 01:05, 25 February 2016 (UTC)

An article with pictures like this might help understand it better. Vespine (talk) 01:09, 25 February 2016 (UTC)

That article is a good schematic illustration of high and low pressure systems but those systems are caused by processes that are essentially unrelated to the daily cycle of heating and cooling. Shock Brigade Harvester Boris (talk) 03:14, 25 February 2016 (UTC)

Mostly they move to colder spots on the planet (hence wind), although some vertical motion occurs as part of the process. StuRat (talk) 01:18, 25 February 2016 (UTC)

When air is heated near the ground it expands. Somewhat paradoxically, this causes an increase in pressure aloft -- you can think of the whole atmosphere being lifted up, though that's not formally correct.

At locations near a coastline this can cause a sea breeze. The pressure surfaces are lifted aloft over land but not over the sea, since the surface temperature of the sea responds only very weakly to the daily cycle of light and dark. This difference causes a pressure contrast between land and sea, which can lead to a sea breeze.

The large scale high and low pressure systems seen on a weather map have very little relation to this daily cycle of heating and cooling. Shock Brigade Harvester Boris (talk) 01:44, 25 February 2016 (UTC)

Ok, i think some of the above is probably causing more confusion than necessary. When air is heated near the ground it expands. Somewhat paradoxically, this causes an increase in pressure aloft . Talking about "increase in pressure aloft" I think is confusing, areas where the air is heated create LOW Pressure zones as seen in weather maps, areas of low temperature creates high pressure, due to plain old equilibrium air travels from high to low pressure. Quote from the link I pasted above "Areas of high and low pressure are caused by ascending and descending air. As air warms, it ascends leading to low pressure at the surface. As air cools, it descends leading to high pressure at the surface. ". So StuRat saying some vertical motion occurs as part of the process. is also incorrect, the vertical motion is what starts the whole thing off, it's not a "byproduct". if wind was actually CAUSED by expanding air you would expect wind to travel from hot areas to cold areas as the hot air expands, but that's the opposite of what actually happens. Vespine (talk) 03:12, 25 February 2016 (UTC)

I didn't say it was a byproduct. I made no statement about which occurs first, the vertical motion or the horizontal. StuRat (talk) 05:23, 26 February 2016 (UTC)

(edit conflict)Firstly, high and low pressure systems of the type that we see on weather maps are caused primarily by baroclinic instability. The daytime solar heating cycle plays a secondary, indirect role at most. So talking about large-scale high and low pressure systems isn't really responsive to the original question.

The initial response to surface heating is that surface pressure remains constant (via the hydrostatic relation). Fundamentally this must be so because air in the column is not created or destroyed. Since the surface pressure remains constant, but the air near the surface expands, it follows (again by the hydrostatic relation) that any arbitrary level of constant pressure aloft becomes higher (in height) than it was before the air was heated. Saying that a given pressure takes on a higher altitude is exactly the same as saying that a given altitude aloft takes on a higher pressure. This is tough to get your head around at first -- even my class of very, very bright grad students last semester had trouble with it.

If the surface is not heated uniformly (which indeed it cannot be, what with Earth being round amongst other things) this will cause a pressure gradient aloft. It is this pressure gradient that then causes the air to move. The lateral transport of mass then leads to surface pressure changes. Shock Brigade Harvester Boris (talk) 03:36, 25 February 2016 (UTC)

If I may pitch again for the fantastic free textbook, Aviation Weather - the very first chapter introduces the atmosphere, and the very second chapter talks about the effect that temperature has on the atmosphere. High temperature reduces air density - so, all other things being equal, that means lower pressure. In actual reality, all other things are almost never equal - so temperature and pressure in Earth's atmosphere can vary as largely independent parameters. This may contradict some of the simplifications that you learn, such as the ideal gas law; although the ideal gas law does still apply, the key concept is that Earth's atmosphere is very big, and there are enormous sources and sinks for heat, mass flux, and so on; so simple models just don't work well. Nimur (talk) 03:21, 25 February 2016 (UTC)

I think I saw in my weather textbook (when I took weather my first year) contrasting surface lows and highs with upper air lows and highs. Warm air at the surface creates a surface low (not necessarily on a weather map / synoptic scale), which rises aloft -- the air column reaches higher altitudes for a given pressure, and is less dense, and "stretches out" more. This means that at the upper air level -- 500 mb, say -- high above the ground, this air column will actually be higher in pressure then the air around it. Likewise, a cold air column will be denser than a warm air column, will create a surface high and an upper air low. So air will flow in a convection-like manner -- at the surface it will flow from the cold air column to the warm one, but at the upper air level, it will flow from the warm air column to the cold one, forming a closed loop. Yanping Nora Soong (talk) 05:32, 26 February 2016 (UTC)

• Not disagreeing with answers above, but just to answer the question as simply as possible: yes, the air goes up. In fact when you have mountains, heating during the day tends to produce winds that blow upslope as the atmosphere expands; cooling during the day produces winds that tend to blow downslope as the atmosphere shrinks. Looie496 (talk) 15:52, 26 February 2016 (UTC)

What does a photon of visible light look like before you see it?

I have heard that the human eye can see even a single photon of visible light. But, before this photon is seen, and absorbed, what kind of physical properties does a photon have as it travels through space? Does it have any dimensions? Is it only visible if one is directly in it's path, or is a photon visible from a vantage point perpendicular to it's direction of travel? Would these answers change if a billion photons were involved? Honeyman2010 (talk) 23:25, 25 February 2016 (UTC)

See Photon and Photoreceptor cell - note that both articles are fairly complex. A photon is a unit (a quantum, to use the technical term) of electromagnetic radiation. It becomes visible when it interacts with the cells of the retina - for it to reach the retina, it has to pass through the eye, so you do have to be directly in its path. I'm not sure about the precise conversion between the number of photons and the intensity of the light (measured in lumens), but a billion probably still isn't enough to read by. Tevildo (talk) 23:44, 25 February 2016 (UTC)

Additionally, as a photon usually travels at the speed of light, the huge Time dilation makes it impossible to "watch" it. There is one exeption tho. With Photonic crystal, because they are able to "trap" photons, you can in a way. So if you for examply buy a nice Opal you can "watch photons" from any angle you like. --Kharon (talk) 01:03, 26 February 2016 (UTC)

Wow, this is a tough one... how much quantum mechanics do you want to learn? How comfortable are you with mathematical abstraction?

We want to treat photons as a point particle, but they just aren't.

Photons have a position - but it's weakly useful, because its position is uncertain. We have to solve for the position, by applying a position operator to a wave function; and then we just get a sort of statistical distribution with information about the position. There is no single point where the photon is - it's spread out over space. In that sense, the photon has extent that is inseparable from its location.

A little bit more abstractly, a photon is a localization of disturbances in the electric and magnetic fields. Where is the disturbance? Well... at a position that can only be described as above, using quantum mechanics. How big is the disturbance...? Well... even the magnitude of the field at any point can only be described using the wave function! So, we need to use a quantum mechanical wave equation just to get to the point where we can apply the electromagnetic wave equation.

The easiest and most intuitive way to walk away from this headache-inducing mess is to succinctly summarize photons this way: photons travel as a wave, and interact like a particle. So - after an event occurs, like when a photon slams into a camera-pixel or a retina-cell, then we can positively describe where it hit, and how much energy it brought. Before that event occurs, the photon is traveling - and the best way to describe it at that time is to fully define it using the wave equation. This is called quantum electrodynamics, and it involves very difficult equations. We'll need to start teaching you a lot of symbology before you can start making headway understanding the way those symbols relate to real observable things.

If you want to read what a famous physicist - specifically, George Gamow, had to say about this: try to find a copy of Mr Tompkins's voyages. This is a very old book, written by one of the founders of modern atomic physics, and it's intended to help interested readers visualize the weird effects of non-classical behaviors. The author presents a view of the universe if fundamental physical constants were different, and among the many adventures that the protagonist experiences, he gets to see the visual effects of relativistic dilations; he gets to see particles interact and collide with photons and with antiparticles; and all sorts of other fantastic things.

Nimur (talk) 01:59, 26 February 2016 (UTC)

Just to summarize the above, a photon is invisible until it strikes something. Now you may wonder why you can sometimes see a sunbeam. Some of the photons are actually striking dust particles in the air, and being deflected into your eyes. That wouldn't happen in a vacuum. There the ray of light would be invisible. StuRat (talk) 05:20, 26 February 2016 (UTC)

To put it a bit differently, when you see anything, it's because photons from the thing you're seeing are entering your eye. Vision is the interaction of photons with your eye. It doesn't even really make sense to talk about "seeing a photon" in the same sense that you see an apple. Mnudelman (talk) 22:12, 26 February 2016 (UTC)

This ties into a question I asked recently about Bohmian mechanics - see this reference I was given then. Apparently the degree to which a photon is a real particle moving along a real path is a matter of interpretations of quantum mechanics, which is to say, the same math predicting the same results can be taken to mean different things intuitively depending on how you look at it, without (I think!) a scientifically testable difference between them. Wnt (talk) 02:29, 27 February 2016 (UTC)

February 26

On the definition of repolarization

I've read in the book of ECG (Mariot): "Electrical systole continues until the positively charged ions are pumped out of the cell, causing its repolarization.". If I would say that the repolarization is defined as entering of negative ions into the cell, I was right? and in addition, is the word "polarization" literal means to positive charge only or to both- negative or positive charge? ThePupil17 (talk) 01:17, 26 February 2016 (UTC)

Polarization means "a separation of charge". See Dielectric polarization. --Jayron32 01:51, 26 February 2016 (UTC)

Yeah, but in neuroscience, "depolarization" means positive deviation of the membrane potential from the resting potential, with the ability to induce action potentials, and hyperpolarization means negative deviation. But you're right, the definition of polarization in the cell biology context is very sign convention-dependent. The membrane potential is defined as the intracellular potential minus the extracellular potential. Yanping Nora Soong (talk) 02:05, 26 February 2016 (UTC)

• Unfortunately even the authors of books often don't understand electrophysiology very well -- neither the statement in the book nor your statement is correct. Changes in membrane potential, including depolarization and repolarization, are primarily caused by changes in membrane conductivity, not by movement of ions. Pumps are essential over the long term but they play no important role on the short term. Our membrane potential article covers these things in some detail, but it isn't easy reading -- this is a topic that many people find difficult to grasp regardless of how clearly it is explained. To fully understand it, it is necessary to make a close study of the Nernst equation and Goldman equation. Looie496 (talk) 15:43, 26 February 2016 (UTC)

high fever (104F) from an influenza infection triggering "drunkenness" (delirium), psychosis and suicidal thoughts

Request for medical and legal advice Tevildo (talk) 08:39, 26 February 2016 (UTC)
The following discussion has been closed. Please do not modify it.
To reframe the question so as to be answered without the provision of medical advice, how often does high fever (such as due to an acute influenza A infection) lead to neuropsychiatric complications (ranging from impaired judgment/delirium to impulsivity to suicidal ideation) in the general population, and is this risk substantially higher in at-risk populations like those suffering from PTSD, schizophrenia or bipolar disorder? Yanping Nora Soong (talk) 02:08, 26 February 2016 (UTC) As often as your doctor tells you when you ask him or her. --Jayron32 02:26, 26 February 2016 (UTC) Something's wrong here. The OP claims on their user page to be a biochemist and "a mental health activist, especially with regards to child abuse, bipolar disorder and PTSD". That being the case, I would think they would know how to research this type of question using professional journals, versus posting questions we can't answer here. General Ization Talk 02:31, 26 February 2016 (UTC) I'm getting results for the side effects of antidepressants (serotonin syndrome) and not for the intersection I want. I don't get literature access until I recover from the flu and get back to work. Also I'm asking about the general population versus mental health population. Why would asking a treatment provider be relevant here, especially as they are not academic researchers? Yanping Nora Soong (talk) 04:32, 26 February 2016 (UTC) Reframe Let me ask this question a different way, the question I actually really wanted to ask: if a patient presents with psychiatric symptoms (including SI) but also with high fever, would it be grounds for medical malpractice if a treatment provider in the ER sent that patient to the psych ward without first ruling out the high fever as a cause of the psychiatric symptoms? That is, wouldn't it be reasonable to suspect high fever as a possible cause of psychiatric symptoms (especially sudden onset), or do these complications happen infrequently enough such that would most doctors not make this connection? Yanping Nora Soong (talk) 04:43, 26 February 2016 (UTC) I'm not sure turning this from a medical advice issue to a medical and legal advice issue really helps. Nil Einne (talk) 07:50, 26 February 2016 (UTC) No one is going to be sued. At worst, a call-out post on social media will be made. Why is this still being classified as a request for medical advice? I am asking what the professional responsibilities of doctors are in this situation in recognizing psychiatric complications of organic illness. Yanping Nora Soong (talk) 08:08, 26 February 2016 (UTC) No one here is qualified to judge whether something would be grounds for a malpractice suit. You need to consult a lawyer. ←Baseball Bugs What's up, Doc? carrots→ 08:10, 26 February 2016 (UTC) @Yanping Nora Soong: Regarding the general issue only of whether flu-like symptoms could be linked with psychiatric symptoms, I think it's worth pointing out that interferon alpha, a natural response to many RNA viruses, can have these effects in some people, such as when it is given to patients to treat hepatitis C. (That much is on PubMed here, and PubMed is available anywhere) The association with influenza itself is not extreme - this abstract says influenza patients have 2.18 times the risk of neuropsychiatric symptoms. But flu-like symptoms can be triggered by a huge range of different things, some of which (like West Nile virus, HIV, and rabies) can affect the nervous system directly. I don't know how long the differential diagnosis takes to rule these out (or indeed, based on those news reports about the Ebola case in Texas, whether they get ruled out at all). I'm thinking a short-term decision to send someone to a psych ward, especially where suicidal ideation is concerned, might be motivated more by a desire to evaluate and control potential complications of the symptoms than to get at the root cause, at least right away. A person in that situation is probably confronted with an abundance of medical advice, and I would not want to contradict any of it, given the many unknowns of the situation. Wnt (talk) 14:20, 26 February 2016 (UTC) @Yanping Nora Soong: I don't know about this issue but I do know about scientific literature and the odd hodgepodge of access control schemes. Most research in the USA funded by the NIH has to be made freely available, but lots of good research is still locked behind paywalls. You might not know of WP:REX, where you can ask for copies of articles. I also often volunteer personal assistance in these matters, and I am happy to fulfill requests for specific articles on my talk page. In general, here [10] [11] are a directory and search engine that can be used to easily find only open-access articles. SemanticMantis (talk) 15:06, 26 February 2016 (UTC)

Launch windows for Mars landers

I am puzzled by a passage in Scott Hubbard’s memoir Exploring Mars. Referring to a decision being made in July 2000, about a mission to be launched in 2003, Hubbard writes:

“Finally, for 2003 the orbital mechanics were very favorable for a lander and this would not be true again for almost fifteen years. The orbital mechanics were not favorable for a solar-powered science lander in 2005, and this decision would give us more time to develop the alternative, a radioisotope power supply for 2007 or beyond.”

I understand that some launch windows (e.g. the one in 2003) are “better” in the sense that you can send more mass to Mars with the same amount of fuel, but what difference does it make whether the lander is powered by solar or by RTG? I would have thought that since the RTG supplies more power it would be used for heavier rovers (like Curiosity) which would ideally be launched in a more favourable launch window. Mathew5000 (talk) 05:27, 26 February 2016 (UTC)

Mars was the closest to Earth since ~50,000 BC in 2003 (and not even similarly close until 2018). It was also very close to the Sun at the same time. The average time between launch windows to Mars is 780 days and it's even longer near "good launch windows" like 2003. The Martian year is only 687 days. Therefore if they went in 2005 it would have to wait most of a Martian year after landing for Mars to get close to the Sun again and the rover couldn't be counted on to live that long (some vital part might fail in the winter (-200°F and twice as long) or a duststorm could cover the solar panels and turn off its electricity) Sagittarian Milky Way (talk) 05:51, 26 February 2016 (UTC)

The way I read this: 2005 was a bad year for a lander - any type of lander - because of the relative orbital positions of Earth and Mars. But - if we wanted to send one anyway - the only technology that was ready to fly was a solar-powered option.

By adding a few extra years, it would be possible to develop and mature an RTG-powered option. Even though RTGs have existed for a long time, every spacecraft design is unique; and it sounds like a spacecraft/lander based around an RTG simply wasn't ready at the time, and couldn't be ready for a ~2005 mission schedule.

To flight qualify a spacecraft design takes a long time, even if it is based on proven, extant technology. This is even more true for a planetary lander, because such missions are so rare, risky, and expensive.

Nimur (talk) 06:16, 26 February 2016 (UTC)

You read it a bit wrong. 2005 is a better than usual launch window for an RTG probe as can be seen here:

It takes about eight years after a perfect opposition for the oppositions to get as bad as possible, not two. The time between "good oppositions of Mars" about 16 years. (They said 15 because the time between oppositions is very close to 2 years plus 7 weeks when averaged over 15-17 years. Oppositions 16 or even 15.5 years apart are therefore impossible because of 1st grade math)

The reason they said 2005 wasn't favorable is because it's very bad for maximizing solar radiation unless the rover survives really, really long. Put the time of arrival of the 2005 launch window in here and it's almost at aphelion. The Sun's distance at arrival would be even worse than I thought as I didn't realize that the 2005 launch window's so late (why? I don't know) Sagittarian Milky Way (talk) 02:10, 27 February 2016 (UTC)

I wonder if they've considered a dual power system, where the (smaller) solar would work when the sunlight was present, and it would run off the (smaller) RTG only when dark, charging the batteries when there is an excess of power coming in. StuRat (talk) 19:16, 26 February 2016 (UTC)

Everything has been considered, including hybrid energy sources. Here's a paper on the MMRTG that's the current state-of-the-art. Here are some archives from the AIAA Joint conferences on Propulsion. Here's a fun paper, Human Missions to Phobos and Deimos Using Combined Chemical and Solar Electric Propulsion.

By virtue of the very long time scales and very massive budgets that are associated with spacecrafts, there is always adequate time to completely investigate lots of possible engineered solutions.

Spacecraft that can afford an RTG rarely need a solar panel, because (as this NASA brief explains), Radioisotope power systems do not require any sunlight to operate. By the time you've got the mass, money, and political clout to build an RTG spacecraft, you'd be laming your mission if you had to work within the energy- and operational restrictions that solar power imposes.

As the NASA Nuclear Power Assessment Study (2015) makes clear, NASA needs nuclear power. (Solar power just doesn't work for the missions that are planned). The more interesting question, rather than "solar vs. RTG", is at what point do we just place a fission reactor (FPS) on the spacecraft?

Nimur (talk) 20:09, 26 February 2016 (UTC)

Does "action potential" is the elctrical systole?

I've read in the book of Mariott that "This movement of ions initiates electrical systole, which is characterized by an action potential.". I don't understand this wording. Does he mean that the action potential is the electrical systole by itself? ThePupil17 (talk) 18:50, 26 February 2016 (UTC)

Term sought

If a person believes in the unbelievable, in something(s) that doesn't exist (things that are not real/realistically proven but the person believes it/in it no matter what others say), what kind of mental disability do they have? What is the correct term to identify this syndrome? -- Apostle (talk) 19:25, 26 February 2016 (UTC)

Faith (the "belief not based on proof" meaning). StuRat (talk) 19:30, 26 February 2016 (UTC)

Faith is what it takes to believe something that isn't true. Bubba73 ^{You talkin' to me?} 19:53, 26 February 2016 (UTC)

I'm searching for a medical term(s)... -- Apostle (talk) 19:45, 26 February 2016 (UTC)

This seems rather in bad faith yes, I giggled at use of "faith here" ... there's no "mental disability" or "syndrome" like this. People have worldviews based on ontologies and some people refuse to alter that worldview regardless of any information given. Everybody believes in things that are not falsifiably or provable (which is why ontology is philosophical). I know of no DSM diagnosis relating to such behavior. EvergreenFir (talk) Please {{re}} 20:07, 26 February 2016 (UTC)

Say for example: When family, relatives, friends, a doctor doesn't believe you, and they say, "How can you be right when everyone else in the world is saying that you are wrong, even the doctor said you are wrong and need medical help." What are they thinking? What's the correct term? - I was thinking of the word abnormal but it does not suffice. -- Apostle (talk) 20:09, 26 February 2016 (UTC)

Closest is psychosis; break with reality and delusional beliefs. Perhaps extreme case of cognitive dissonance. EvergreenFir (talk) Please {{re}} 20:11, 26 February 2016 (UTC)

Right, we do have an article on delusion, and that is something that can be diagnosed. As for good faith, OP here is better known to me than you are, and I know him to be earnest, curious, and ESL. He may not always express himself clearly but I'm pretty sure he's not out to smear religion, even if some of our readers may draw their own conclusions about delusion and faith in the supernatural ;) SemanticMantis (talk) 20:14, 26 February 2016 (UTC)

Sorry given all the troll socks on the ref desks, I'm perhaps not assuming the best of faith. I'm new to the ref desks and added then to my watchlist because of the socks. Thanks for the minor trouting and sorry to Apostle. EvergreenFir (talk) Please {{re}} 20:22, 26 February 2016 (UTC)

Hallucination may also be relevant. Not all people believe their hallucinations to be true or real, but some do. SemanticMantis (talk) 20:20, 26 February 2016 (UTC)

Confabulation is another possibility, which is remembering things that haven't happened. Tevildo (talk) 21:22, 26 February 2016 (UTC)

Are you including religion? If your nation is largely of a particular religion, a follower of that religion is not likely to be called anything except a "good [Christian, Jew, Muslim, Hindu, Buddhist, or whatever]". If they believe something that "sounds crazy" or outside the norm of the community's religion, they might be labeled as such. Hence the ridicule of Linus for believing in an alternate god-like being called "The Great Pumpkin". ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:42, 27 February 2016 (UTC)

Yes (whatever/whichever Wikipedia article(s) states really).

Its not like as you guys are thinking, so no worries... It's a great disappointment...everything is off of Wikipedia, with a bogus little story...

Religion, politics and science are not my topic – I’m rubbish at all three. I would’ve used them for my “fictional” character, (but as Jayron helped me understanding), but I’ve cancelled them including my personal philosophy because I’m meddling with religious and mythological stuff; in a manner. I do want people to be manipulated, basically take all the Zecharia Sitchin's fans; of course others if possible too...

The good and the bad ones who turn[ed] good, will understand because, they are the “good” and the “bad" ones who turned "good”… And the bad and or the evil ones? Not my brain and not my free will...

I do have mental disability(s), but I do not wish to receive a certificate from a doctor… If somehow this plan also gets cancelled than, I’m just hoping that I can manipulate people to pay me for my illness – if Kayne West and Syrians (who have smart phones and ipads but not me ) can, than – so that I can live my life; and or work (if possible, not guaranteed with the mental illness, plus "the world and its creatures are not my problem" anyway ",~7.2 Billion exist..." - if you know what I mean. )…

Thank you all for the information for analysis; I’ll read through…

Love you Wiki-Ladies!

Apostle (talk) 00:05, 28 February 2016 (UTC)

February 27

Rietdijk–Putnam argument

I was reading the article on Rietdijk–Putnam argument, specifically the Andromeda paradox and it got me thinking. So the car driver can see the Andromeda galaxy one entire day ahead of the pedestrian. If he were to slam on the brakes or make a U-turn, wouldn't he see the events in the Andromeda galaxy slowing down significantly or even unfolding backwards in time, and wouldn't that create pretty much the mother of all Doppler shifts? 93.136.14.136 (talk) 01:55, 27 February 2016 (UTC)

Your intuition about planes of simultaneity going backwards in time is correct, but you don't see events on a plane of simultaneity. What you actually see is events on your past light cone, and your past light cone at a given moment doesn't depend on your speed at that moment, so changing your speed doesn't instantaneously change what you see.

The redshift/blueshift you will see if you're moving at velocity v toward/away from Andromeda is ${\sqrt {\frac {1+v/c}{1-v/c}}}$. Acceleration doesn't affect that except inasmuch as it changes your velocity. The speed of everything is changed by the same factor—a factor-of-2 blueshift not only doubles the frequency of all light but also makes clocks appear to be running twice as fast and so on. The factor is never negative so time never appears to run backwards.

Rietdijk and Putnam's argument only demonstrates that they don't understand special relativity. Planes of simultaneity are physically meaningless. There's no experiment that can detect the "present existence" of things on a plane of simultaneity. In fact a "computer running the universe" can store just the present state of the universe on some spacelike surface. It doesn't have to keep earlier states around. That's not to suggest that the universe really works that way, but the existence of that model means that any argument that the past must still exist is wrong. -- BenRG (talk) 08:32, 27 February 2016 (UTC)

The main confusing thing about relativity is that different things change at once. Suppose for ease of illustration you walk toward a galaxy at relative rest to you (not Andromeda). Your light cone tips toward it, and "the same time" there (for you) becomes earlier. And the distance to the galaxy becomes less (Lorentz contraction). And the rate at which time is passing on it changes (time dilation). And the light reaching you from it seems bluer, which represents a general fast-forward in how events on it seem to be playing out (which is different from the time dilation, because your view of the light depends on the galaxy's apparent motion toward you). Keeping track of all these things is challenging, but somehow the math all works out. But when we say simultaneity is "meaningless", what that really gets at is that there's nothing to calculate - you can't see time reverse this way, once all the other factors are considered. Wnt (talk) 09:27, 27 February 2016 (UTC)

The light cone doesn't tip. Its direction is fixed by the geometry of spacetime. There's a different light cone for every spacetime point, but not for different speeds.

The rest of what you said is mathematically true, but physically meaningless. It's exactly analogous to the following in Euclidean geometry: draw a straight line (Andromeda's worldline) and a curve (your worldline). Then draw lines perpendicular to the curve and see where they intersect Andromeda. When your curve bends away from Andromeda, the intersection with Andromeda moves rapidly forward in Andromeda time. When your curve bends toward Andromeda, the intersection with Andromeda moves rapidly backward in Andromeda time. When your curve is straight but not parallel to Andromeda's, the intersections with Andromeda are spaced farther apart than the intersections with you (time dilation). This is all true, but why were you drawing those perpendicular lines? The two worldlines represent the locations of two physical objects in spacetime, but the lines between them represent nothing. Absolutely nothing. I always have trouble convincing people of this because every introduction to relativity assigns enormous importance to these perpendicular lines. But they are 100% human inventions. -- BenRG (talk) 22:24, 27 February 2016 (UTC)

Names of newly discovered taxa

The question was asked previously, but having read I think it missed the point when it comes to novel species discovered in modern era. For example, crested eagle described by French Daudin in 1800 is known in French as "harpie huppée" and in Russian as "гвианская гарпия" (literally, Guinean harpy). Obviously Daudin wasn't the one who gave it English or any other non-French common name. Who gives such common foreign names? Or the family Mimid (introduced by Bonaparte in 1853), which in Russian is called Пересмешниковые (literally, the mockingbirds). What authority usually assigns foreign-language common names in such cases? Brandmeister^talk 09:54, 27 February 2016 (UTC)

1) English is not the default language of the world, and "foreign language" is not subservient to English. 2) Common names are not necessarily assigned by any authority in every known language in the world. No one decided that the Spanish word for dogs would be "perro" and it would be "chien" in French and 犬 in Japanese. There is not a central committee in the world which decides what every language will use for its own words. --Jayron32 16:27, 27 February 2016 (UTC)

That's obvious, I mean new species for which there was no prior knowledge and consequently, a common name. Who gives them common names in languages other than that of scientific description? Brandmeister^talk 20:01, 27 February 2016 (UTC)

But from Bengal to Belize and Las Vegas to Lahore, the language of the sceptered isle is rapidly becoming the first global lingua franca. AllBestFaith (talk) 18:25, 27 February 2016 (UTC)

Science papers with photographs of the authors on the first page

Today I came across this weird paper with color photographs of the authors on the first page[12]. I've never seen something so bizarre before.

How common is this? I.e. what percentage of scientific papers have photographs of the authors on the first page?Johnson&Johnson&Son (talk) 12:29, 27 February 2016 (UTC)

Very uncommon. If you read German, de:Metalurgia International has the story of this particular paper and journal - basically, the journal is known as a pay-to-publish vanity press without proper quality control, and the paper was written as a sting operation to uncover this. --Stephan Schulz (talk) 12:44, 27 February 2016 (UTC)

In mathematics, the College Mathematics Journal, published by the Mathematical Association of America, has color photos of authors on the first page. So the practice is not entirely limited to the vanity press. Loraof (talk) 15:00, 27 February 2016 (UTC)

By coincidence, just today when researching for a WP article, I found this[13] (note the photos). This journal has been around since 1992 and I doubt very much it would be described as a vanity journal. I don't know whether photos appear on a hard-copy of the journal.DrChrissy ^(talk) 16:57, 27 February 2016 (UTC)

Follow-up. It looks as though the photos are inserted by ResearchGate, rather than the journal.DrChrissy ^(talk) 17:01, 27 February 2016 (UTC)

It's fairly common for posters at conferences to have pics of the author(s) at the top. In that case the pics have practical value, so that you can recognize the authors in the crowd and ask them about their work. But that obviously doesn't apply for a journal article. Honestly, I can't see any point whatsoever in having pics of the author in a journal article other than ego and flashiness. For better or worse we'll probably see more and more of this as journals try to jump on the social media bandwagon. Shock Brigade Harvester Boris (talk) 17:14, 27 February 2016 (UTC)

It depends on the field and journal, to some extent. Generally speaking, I've found it's rare to see it on research papers, but it does sometimes happen with review and perspective articles. For example, Angewandte Chemie (a highly respected journal in chemistry) doesn't do anything like it for its research papers, but all of its review articles have photographs and short biographies of all the authors as part of the article itself. (As does ChemBioChem, from the same publisher.) Chemical Society Reviews and some of the other journals from the Royal Society of Chemistry do this as well. ACS Chemical Biology doesn't attach pictures and biographies to the papers themselves, but does have a separate "Introducing Our Authors" section, which has selected pictures and bios for both review and research authors. In contrast, the Journal of the American Chemical Society (by the same publisher as ACS Chemical Biology) normally doesn't provide any sort of biography or photographs at all. - To make an unsupported generalization, I'd say including photographs and biographies on reviews tends to be more prevalent in European journals, and less so for American ones, though that's not hard-and-fast. -- 160.129.138.186 (talk) 20:22, 27 February 2016 (UTC) (by edit request) ―Mandruss ☎ 20:35, 27 February 2016 (UTC)

As I recall, IEEE papers have tended for a very long time to have a black-and-white photo with a one paragraph bio for each author at the end.

Question: which Open Access journals do this, and should we be copying the photos to Commons? Jheald (talk) 21:01, 27 February 2016 (UTC)

Does this mean articles in Open Access journals are not subject to copyright?DrChrissy ^(talk) 21:08, 27 February 2016 (UTC)

DrChrissy That depends on what kind of Open Access :-) PLOS use CC-BY [14]. There's a fair amount of discussion of gratis vs libre at our article Open access. Jheald (talk) 21:14, 27 February 2016 (UTC)

Thanks for the reply. I was thinking about copyright in terms of using images from Open Access journals. I'll raise it as a specific question at Commons next time I feel the need to use an image. DrChrissy ^(talk) 21:17, 27 February 2016 (UTC)

You need to check the terms for the particular journal; possibly even the particular article in some cases, I think. Commons has (or had) a c:Commons:Open Access File of the Day, though I don't know whether or not that's still running; there's also c:Category:Open access (publishing) which contains categories of images from different OA journals; while here on Wikipedia there is Wikipedia:WikiProject Open Access. Jheald (talk) 22:10, 27 February 2016 (UTC)

Why is everyone whispering? Shock Brigade Harvester Boris (talk) 01:10, 28 February 2016 (UTC)

• Agreed it's not unheard of for review articles. I wrote an invited review for a new-ish but serious biomedical journal two years ago and was somewhat surprised to have them ask for photo and potted biography. Fgf10 (talk) 23:55, 27 February 2016 (UTC)

Gigameters

I see that all the usages of astronomical distances when using SI multiple of meters is in kilometers, most commonly in millions. Why don't gigameters be commonly used instead, it's the one-word unit for millions of km? Earth's distance from the Sun is 149.6 Gm, which is the same as 149.6 million km. Whether gigameters should be referred instead of millions of km would be up to astronomers. I can see this unit will eventually be adopted for common astronomical use. PlanetStar 02:18, 28 February 2016 (UTC)

Pregnant pilot

Suppose an aviatrix who regularly flies unpressurized aircraft (such as those used in air taxi operations) was to become pregnant -- how would this affect her ability to withstand mild-to-moderate hypoxia (such as that caused by flying at altitudes from 8,000 to 12,500 feet (and up to 14,000 for short periods when necessary) without pressurization)? Would she have to stay below 10,000 feet or below a still lower altitude for the next 9 months? (NOT INTENDED AS MEDICAL ADVICE) 2601:646:8E01:515D:F88D:DE34:7772:8E5B (talk) 02:31, 28 February 2016 (UTC)