Wikipedia:Reference desk/Archives/Science/2011 June 28

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June 28

Multiple sclerosis

What is meant by t1 or t2 lesion load? how does it differ from active lesion? — Preceding unsigned comment added by 199.224.149.10 (talk) 04:32, 28 June 2011 (UTC)

I can't give a detailed answer, but I can tell you that T1 and T2 are different ways of carrying out an NMR examination. This paper describes them in detail, if you can make sense of it. Looie496 (talk) 05:15, 28 June 2011 (UTC)

To explain in better detail, see Magnetic_Resonance_Imaging#Basic_MRI_scans. T1 and T2 refer to two different MRI techniques (the MR in MRI is the same MR as in NMR and the terms (NMR and MRI) are occasionally used interchangably, though mostly NMR is reserved for the analytical chemistry technique, while MRI is used for the medical diagnostic technique. The authors of this paper are really refering to MRI). The technical details of each can be found in the article I cited, but for the purpose of the OPs question, and for the purpose of understanding that paper, the T1 and T2 lesion loads are merely the number of lesions detectable on a T1 scan versus a T2 scan. Each type of scan has different sensitivities, so they have different applications; some times you'll want to do a T1 scan and sometimes a T2 scan. The paper you cited is the results of various experiments to determine the ideal parameters for using MRI to detect multiple sclerosis lesions. --Jayron32 05:27, 28 June 2011 (UTC)

Colloquial medical expressions

When someone dies of a "hole in the heart", what did kill him? And what about the classical - "dying of old age"? Does that simply mean "old person died, don't know why"? Wikiweek (talk) 14:39, 28 June 2011 (UTC)

The former may often be ventricular septal defect -- Finlay McWalter ☻ Talk 14:43, 28 June 2011 (UTC)

Or an atrial septal defect. In a society with current medical care it would be unlikely for an adult to die of any kind of septal defect, since it would usually be repaired before significant hemodynamic consequences developed; a very large or complicated septal defect in an infant could cause death. --- Medical geneticist (talk) 22:04, 28 June 2011 (UTC)

From Death_by_natural_causes: "Old age is not a scientifically recognized cause of death; there is always a more direct cause although it may be unknown in certain cases and could be one of a number of aging-associated diseases." SemanticMantis (talk) 14:49, 28 June 2011 (UTC)

In the case of a "hole in the heart" due to injury, as in a bullet wound, it might be in any part of the heart, or perhaps nearby, say in the aorta or vena cava. In this case the victim is likely to hemorrhage to death, with the loss of blood pressure probably actually causing brain death. StuRat (talk) 16:19, 28 June 2011 (UTC)

When someone dies of a broken heart, see article broken heart syndrome. ~AH1 ^(discuss!) 01:19, 30 June 2011 (UTC)

Quantum superposition

Hello,

How does quantum superposition fit in with the principle of contradiction? It seems like QS can allow for a statement and its negation to be jointly true (i.e., "Schrödinger's cat is dead" and "Schrödinger's cat is alive" are both true at the same time). Does this mean the principle of contradiction is wrong?

Thank you. Leptictidium (mt) 15:09, 28 June 2011 (UTC)

The principle of contradiction is logically sound. What is not clear is what is meant when you state that the cat is alive or that it is dead. Are those two states truly logic opposites to each other? QM says that these statements are not the logic negation of each other since a third state is also possible, namely the cat might be in quantum superposition state. Dauto (talk) 15:34, 28 June 2011 (UTC)

But QS is not a state in and as of itself, it's merely a superposition of states, right? Leptictidium (mt) 15:36, 28 June 2011 (UTC)

No, it is really a real state. If |a> and |b> are two orthonormal states, then so are |a'> = 1/sqrt(2) [|a> + |b>] and |b'> = 1/sqrt(2) [|a> - |b>]. Count Iblis (talk) 15:40, 28 June 2011 (UTC)

Quantum mechanics makes a clear, definitional distinction between the state of the system, and the observable state of the system. We have an article on this concept: observable. Something that is still a superposition of states is not observable. When you measure the state, you are observing one of many possible states. Nimur (talk) 15:45, 28 June 2011 (UTC)

Sorry, but that's plain nonsense. You can transform any observable using any arbitrary unitary transform to yield another observable. That such observables (whose eigenstatstes are superpositions of the previous ones) can't in practice be measured is not an issue, in principle you can measure a cat in a superposition of being dead and alive. Count Iblis (talk) 17:40, 28 June 2011 (UTC)

Therefore, no truly logic opposites can exist, since there will always be a third state possible. Yes? --Leptictidium (mt) 15:57, 28 June 2011 (UTC)

No. Count Iblis (talk) 17:41, 28 June 2011 (UTC)

Logic opposites are possible but the opposite of an electron with spin up is NOT an electron with spin down. The logis opposite of an electron in a spin up state is an electron that is not in a spin up state but could conceivably be in a superposition of states between spin up and spin down. A familiar example might help. The logic opposite of moving northward is NOT moving southward. That opposite would be not moving northward which might mean you are moving northwestward. Dauto (talk) 16:30, 28 June 2011 (UTC)

I prefer to phrase it this way. For example, let's take electron spin in the hydrogen atom. It can either take the value +1/2 or -1/2. When it is not measured, I do not say, "the particle is both spinning with +1/2 and -1/2." Instead, I phrase it as "the particle's spin is not measured. Here are the probabilities that it may be +1/2: (math); and that it may be -1/2: (math)." I think this simple choice of phrase makes quantum mechanics seem a lot less silly. But, if you want to say "the particle is both spinning up and not spinning up," (or, "the cat is both alive and dead"), you can very well phrase it that way. It's still silly. Nimur (talk) 16:08, 28 June 2011 (UTC)

Who said QM is not supposed to sound silly? If the electron is in a quantum superposition of a spin up and a spin down state than it is truly both at the same time. Dauto (talk) 16:15, 28 June 2011 (UTC)

You guys are all basing your statements on only one of the many possible Interpretations of quantum mechanics, specifically the common Copenhagen interpretation, which deals with such things as things existing in multiple states simultaneously, and with observation causing "collapse of the wavefunction" to produce the result; that is that the observation itself causes the result, somewhat non-mechanisticly. There are other, perhaps equally valid interpretations, such as the Ensemble interpretation, which takes a more agnostic view on the connection between quantum mechanics and reality. The mental gymnastics which is sometimes required (such as our simultaneously alive-and-dead cat) to make the Copenhagen interpretation work is philosophically unsatisfying. It is perhaps really much better to just state that our knowledge of the cat's living/dead state is incomplete without observation. In any instant, it may be alive or it may be dead, but it will be definately one or the other of them, irrespective of our observation. What changes is which variables we feed into our equations to decide if it is alive or dead; once we observe the cat. The distinction is deciding whether or not the event occurs only at the moment of observation or at some impossible-to-determine time before the observation. While philosophically the second proposition feels better, the first proposition actually makes the mathematics much simpler, since it gives us a specific point in time to determine when the "event" occurs; since it doesn't actually matter "when" prior to our observation, and since it is literally impossible to know "when" without observing it (i.e. you literally cannot determine the living/dead state of the unobserved cat unambigously from first principles, you can ONLY determine it empirically via observation), the first proposition works better for the purposes of making the math work. The end result is it doesn't really matter (from a scientific point of view) which "interpretation" works better for you, philosophically (that's why these are "interpretations" and not theories or laws or models, they don't require rigourous proof), the equations yield the same results either way, which is just the probability of the cat being dead as a function of time, and nothing more. What quantum mechanics does is destroy our belief in the "clockwork universe", that somehow given a perfect knowledge of initial conditions, one can deterministicly predict exact outcomes of any event before it happens. QM clearly shows this to be not true; one can only predict the probability of any event happening; even perfect knowledge of initial conditions cannot, for example, predict the exact time when a single discreet particle will decay. --Jayron32 16:48, 28 June 2011 (UTC)

Bohr didn't believe in wavefunction collapse as a physical process, so to the extent that "Copenhagen interpretation" means "Bohr's interpretation", the Copenhagen interpretation doesn't have wavefunction collapse in it. I don't think he believed in physical superpositions either.

The testable predictions of quantum mechanics are probabilities of the form $\left|\,\langle \psi _{f}|\,{\hat {U}}\,|\psi _{i}\rangle \,\right|^{2}$. This is the probability that if you prepare a system in the state $\psi _{i}$ and subject it to a physical environment described by ${\hat {U}}$, you'll then find it to be in the state $\psi _{f}$. The idea of wavefunction evolution and collapse is that, after you prepare the wavefunction in state $|\psi _{i}\rangle$, it changes gradually into ${\hat {U}}|\psi _{i}\rangle$, which is generally not the same state as $|\psi _{f}\rangle$. This mismatch is resolved by having the wavefunction suddenly, discontinuously jump from ${\hat {U}}|\psi _{i}\rangle$ to $|\psi _{f}\rangle$ at the moment of the measurement. There's no evidence that this happens; it's not experimentally testable. You could just as well say that the wavefunction suddenly "decollapses" to the state ${\hat {U}}^{\dagger }\,|\psi _{f}\rangle$ immediately after the preparation, then gradually evolves from there to $|\psi _{f}\rangle$. This kind of arbitrariness is the reason it's problematic to take an evolving wave function as the ultimate physical reality. -- BenRG (talk) 06:00, 29 June 2011 (UTC)

Example: Deutsch' thought experiment involving superpositions of entire observers observing different outcomes. Here one considers observing the z-component of a spin that is polarized in the x-direction. If the whole system of observer plus spin is isolated from the environment, the entire system will be a superposition of the two outcomes. Then the observer in each branch forgets, in a reversible way, the outcome of the measurement, by dumping the information back on the spin. That then restores the spin to its initial state. The observer, however, does keep the information that a measurement of the z-component was carried out.

The observer can then verify that the spin is polarized in the x-direction after this procedure, even though he remembers measuring the z-component. This then proves that when the z-component was measured, both sectors in which different outcomes were obtained really exist (if only one sector really exists after measurement, the spin would not be restored to its original state). Count Iblis (talk) 18:00, 28 June 2011 (UTC)

Another example: Quantum mechanics in a timeless universe.

Many theoretical physicists believe that time doesn't exist (my opinion is that those that do think time exists mostly haven't thought this issue through to its logical conclusion). Then the world today can, in this interpretation, be said to exist in the early universe as a complicated non-local superposition. Count Iblis (talk) 18:28, 28 June 2011 (UTC)

Jayron, you can interpret QM however you want. That will not change the fact that, as Count Iblis pointed out, |a'> = 1/sqrt(2) [|a> + |b>] is also a possible state so superposition of states is allowed. This has been confirmed by experiment ad nauseam. Dauto (talk) 01:00, 29 June 2011 (UTC)

Nothing I said has ever denied that. I, infact, fully endorse that, and I will again thank you for agreeing with me. The equation noted by Count Iblis is true, and doesn't need me to agree with it to be true. I don't see where I ever said it was wrong, however. The real existance of superposition of states is real and really exists. I don't know how many more ways I can say that to make you think that I agree with it, which I do. (and again, my agreement is not needed for its real truth to be really true). I should also note that I don't interpret quantum mechanics in any manner. I don't have any particular wants about how it is interpretted, and have nothing to add to existing scholarship on the issue. --Jayron32 01:04, 29 June 2011 (UTC)

Quantum logic may be relevant to this question, but I'm not sure since I never grokked it. -- BenRG (talk) 06:00, 29 June 2011 (UTC)

See also duality. QS supposes that an observer is required to mediate between the two outcomes and break the symmetry of duality, and until then both outcomes are realized. ~AH1 ^(discuss!) 01:18, 30 June 2011 (UTC)

MRI question

Would an MRI be better at finding bullet fragments then an xray? Googlemeister (talk) 15:45, 28 June 2011 (UTC)

You probably need to define "better." MRIs are bulkier, more expensive, and harder to transport than a standard x-ray radiograph imager. Nimur (talk) 15:47, 28 June 2011 (UTC)

There are risks with taking MRIs of bodies containing magnetic metals. Even though bullets are typically made of non-metallic lead, there may be fragments of magnetic metal from the shell casing, and steel ammunition is sometimes used (e.g. in shotgun pellets). Studies show that the metal fragments are unlikely to move much, but there is a risk of damage to internal organs.[1][2] --Colapeninsula (talk) 15:55, 28 June 2011 (UTC)

"Non-metallic lead" ? I assume you mean "non-magnetic". StuRat (talk) 16:10, 28 June 2011 (UTC)

Better as in more likely to find the bullet fragments, the bulkyness of an MRI vs an xray machine is probably not of paramount importance (unless you are talking about military field applications I suppose) since both are too large to fit into your standard ambulance and cost usually isn't the biggest concern of someone with a bullet in them. I did not consider that some ammunition was steel. I guess I need to read up on that. Googlemeister (talk) 16:07, 28 June 2011 (UTC)

I would expect bullet fragments to show up quite nicely on an X-ray, so no need to resort to the more expensive MRI. StuRat (talk) 16:11, 28 June 2011 (UTC)

To expand on StuRat's statement, I would expect that (ignoring all other factors such as cost and complicatedness of use, complications due to magnets, and other issues) that an X-ray would be equally as good as an MRI in finding bullet fragments, that is once the image is obtained, a trained professional should have no more trouble finding a bullet in the image with an X-ray image than with an MRI image. If we include the other issues already noted above, the X-ray is probably better than an MRI for this application. --Jayron32 16:14, 28 June 2011 (UTC)

Here's a useful link: a research paper that performed comparative virtual autopsy using MRI and CT, and comparing them to the X-ray radiography: Image-guided virtual autopsy findings of gunshot victims performed with multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) and subsequent correlation between radiology and autopsy finding (2003). Nimur (talk) 16:17, 28 June 2011 (UTC)

I think there needs to be some clarification on your use of the term "x-ray" -- CT scan machines emit ionizing radiation, as do conventional x-ray machines, so what exactly would be your criteria for separating the two? Projectional x-ray images (such as a chest x-ray or a dental panoramic radiograph) would not locate the bullet fragments in 3 dimensions, making localization of the fragments for surgical removal difficult. A full body CT scan (or CT scan of that portion of the body known to possess the fragments would allow the practitioner to see the fragments in an axial slice. Whether or not MRI would be better or worse, though, I cannot say, because (as a dentist) I'm completely unfamiliar with MRIs. DRosenbach ^{(Talk | Contribs)} 17:00, 28 June 2011 (UTC)

With traditional X-rays, they take two, at 90 degree angles, to locate objects in 3D. For example, one from the front and one from the side. StuRat (talk) 17:43, 28 June 2011 (UTC)

Actually MRIs are very bad for finding metal. Metal objects don't even show up on an MRI; they distort the image in the area around them, though, making it sometimes possible to deduce their presence. Also if the metal is magnetizable (lead is not), the magnetic fields in an MRI will exert a strong force on it, which is obviously not a very good thing for a bullet fragment. CTs are absolutely perfect for finding metal, even tiny pieces just leap out at you if you look at one. Looie496 (talk) 02:10, 29 June 2011 (UTC)

I was just about to say the same thing, but Looie beat me to it. Panel (b) of the figure on this page shows an MR image of a brain with a bullet lodged inside. The bullet's distortion of the magnetic field causes the dark 'hole' and the adjacent bright 'flare'; you'd see something similar with any metallic object. Not only does it make it very difficult to precisely locate the bullet itself, but it also conceals and distorts the appearance of nearby anatomical structures. With steel (or other ferromagnetic) shrapnel, pellets, or bullet fragments, one also has the additional risk of local heating and migration of the metal item in the magnetic field, which may cause pain or injury. TenOfAllTrades(talk) 02:39, 29 June 2011 (UTC)

Multiple Alleles

Hello. If the dominance hierarchy of coat colour in Netherland Dwarfs is C (dark gray) > c^ch (chinchilla) > c^h (light gray) > c (albino), why do c^chc^ch and c^chc code for light gray instead of chinchilla and why do c^hc^h and c^hc code for point restricted instead of light gray? Thanks in advance. --Mayfare (talk) 17:36, 28 June 2011 (UTC)

Because binary genetics (even multiple allele binary genetics) is rarely useful for anything more than pedagogical purposes; that is it is helpful in demonstrating the basic principle, but in actual practice, the physical traits expressed by genes are often the result of complex effects, sometimes in the second or third order (for example, the gene doesn't directly code for the structure of the pigment, it codes for the structure of a component of the pigment, or it codes for the structure of a substance that is involved in the manufacture of the pigment some several steps back from the pigment itself). In particular, broad traits such as pigmentation represent what are called polygenic traits which are coded by multiple genes. For some analogs in humans, see Eye_color#Genetics and List_of_human_hair_color_genes, which lists for humans some 12 genes responsible for hair color; you'll also note that many of these genes code for things OTHER than hair color as well, that is there are not only multiple genes which determine hair color, there are multiple traits coded for by each gene (of course, depending on how you define "trait"). I would expect the genetics of other mammals to be similarly complex. --Jayron32 19:09, 28 June 2011 (UTC)

I took the liberty of linking Netherland Dwarf above, as I didn't know it was a rabbit. ;) (Oryctolagus cuniculus to be precise) Here's a public access paper about the E (extension) locus and a similar dominance sequence,^[3] but I'm still hunting... alright, finally got someone to say that the c (albino) locus is indeed tyrosinase in O. cuniculus^[4] (never take that sort of thing for granted...) chinchilla and albino alleles are indeed due to mutations in the CDS (compared to C (dark gray). Which leaves light gray... didn't find that; there's only one sequence coming up in NCBI, namely [5]. I even ran a BLAST search and came up with no other nucleotide sequences. It looks like the relevant work may be so old it isn't indexed - indeed, perhaps the sequence was never determined. This is generally the point where you have to pick up a phone and call someone on the last paper to come out about it in the hope of getting some answers, which I'm not going to do now for this exercise; my guess is that we're looking at some very old data. So I can't say exactly why these alleles would have a more peculiar dominance pattern. Also, the data you describe sounds unlikely - I'd expect two recessive alleles of the same type to deliver the advertised phenotype! Hmmm... for further information see [6] - it's apparent there is a lot more breeding of rabbits going on than I'd ever imagined! ;) And yes, two chinchilla alleles can lead to a light gray color, though there's some lingering confusion on the point. Hmmm, so much data and so few sequences in NCBI :( Wnt (talk) 23:19, 28 June 2011 (UTC)

From the Caspian Sea to the Black Sea

I included two questions in a posting above, and one of them got no attention, so here it is alone.

Is there any truth in Leonardo da Vinci's statement that there are subterranean rivers flowing from the Caspian Sea to the Black Sea? Michael Hardy (talk) 20:49, 28 June 2011 (UTC)

That seem highly unlikely as the Caspian Sea is actually 28 metres lower than the Black Sea and there is the Caucasus mountains in between. Any river flow would be from the mountains of the Greater or Lesser Caucasus ranges into one or the other seas. Mikenorton (talk) 21:17, 28 June 2011 (UTC)

As an aside, there has been means of getting between the seas for quite some time. The Volga–Don Canal goes back several hundred years; and since the Volga and Don are relatively close (100 km or so), that makes portage between the rivers (and thus between the Caspian and Black seas) reasonable even before the canal was built. However, this has nothing to do with natural river flows between the seas; as noted water generally doesn't flow uphill. --Jayron32 23:24, 28 June 2011 (UTC)

The Volga–Don Canal seems to go back to 1952 except for a couple years in the early 1700s. Rmhermen (talk) 02:55, 29 June 2011 (UTC)

You may also be interested in Lake Manych-Gudilo, Paratethys and Black Sea deluge theory. The salinity of the entire region is explained by previous sea level rise (25+ metres), though not necessarily by any subterranean rivers. ~AH1 ^(discuss!) 01:15, 30 June 2011 (UTC)

The 28 meters difference seems like a pretty cogent point. So I wonder: how did da Vinci reach that conclusion? Michael Hardy (talk) 18:32, 30 June 2011 (UTC)

It's very likely that at the time that Leonardo was alive that no-one realised that there was such a difference in surface level - topographic maps didn't become available until much later. I don't know why he thought there was a connection, although the understanding of what went on beneath the earth's surface was pretty rudimentary at the time. Mikenorton (talk) 18:54, 30 June 2011 (UTC)

Are we evolving?

Is the human species evolving? Indeed, since modern medicine is able to keep alive humans who would die under other circumstances, then, we are indeed getting weaker. Wikiweek (talk) 21:49, 28 June 2011 (UTC)

As long as some people die earlier, and reproduce less, than others, evolution will continue. It might possibly slow down or evolve in a different direction (say favoring people genetically predisposed to use seat belts), but it won't stop. StuRat (talk) 21:52, 28 June 2011 (UTC)

Evolution is just gene flow over time. That happens just by living and reproducing and so forth. If you mean, "are less favorable traits being selected for over time?" (e.g. dysgenics), it really becomes a question of what one defines as "less favorable." It's a pretty subjective measurement and the level of subjectivity becomes clear when you consider some traits that are widely shared and found to not be such a big deal, but would have been a significant hindrance (or even fatal) a long time ago, such as poor eyesight or appendicitis. In the case of IQ, there is evidence that has only risen over time (see Flynn effect). If by "weaker" we mean only "that they would have not survived without modern medicine," we can only then ask why we should take that as a meaningful criteria. There are lots of people who wouldn't have survived without modern morality or social institutions, in general. What does that tell us except how lousy the past was?

It's also a fallacy to consider modern medicine somehow "unnatural" to the species. It's as natural as anything else we've been up to. It's new (from a species-long perspective), but that hardly makes it any less "natural". --Mr.98 (talk) 21:59, 28 June 2011 (UTC)

Would the Flynn effect imply that intelligent people have more offspring than the stupid ones? Otherwise, it might be a non-genetic effect. — Preceding unsigned comment added by 88.9.106.0 (talk) 10:49, 29 June 2011 (UTC)

Define "weaker". Without "modern medicine" Stephen Hawking would have undoubtedly died from his disease long before he made many contributions to our understanding of how the universe works. Insofar as an improvement and refinement to the canon of human knowledge is generally a Good Thing, modern medicine has made people stronger. Also, there is the problem with defining humans as somehow "extranatural", that somehow what happens to us or is done by us is somehow outside of "nature", whatever that means. We're particularly good at altering our environment and ourselves in ways that benefit us (at least in the short term), but we're not unique in that regard; every other living thing constantly does that. We alter the environment in human ways, but that's not necessarily a meaningful statement; rabbits alter the environment in lupine ways, and trees alter the environment in dendritic ways. We're active parts of the system, not passive managers or observers of it... --Jayron32 23:20, 28 June 2011 (UTC)

Yes, I like to refer to "artificial" as a subset of "natural", as anything man-made is indirectly made by nature. StuRat (talk) 23:24, 28 June 2011 (UTC)

It's true that saving people who would have died frustrates one small step of natural selection - but natural selection, like death, is patient, and sooner or later - unless we fix such genes ourselves - it will drink its fill. Many of the genes we possess are optimized for conditions we don't expect to experience. Consider, to begin with, how remarkable it is that a species from Africa can survive exposure of any part of its skin to the bitter cold of the Arctic - because there have been some very cold years indeed, long ago. Mutations like the one in CCR5 were probably kept by our ancestors for thousands, maybe even millions of years, as a distant memory of other HIV-like outbreaks before this one - and, most likely, the same is even more true of the normal variant most people carry, against some other disease not yet identified.

In order to make good decisions about genetic therapy to compensate for the loss of natural selection, we should recognize that alleles arise at some point in history, and that while some are ancient and valuable, others are recent and have no special historical significance. Many of the cruelest genetic diseases are of the latter sort, arising in the person affected, or some recent ancestor. If we resolve to preserve the range of genetic diversity we inherited from people 1000 or 10000 years ago, while resolutely putting right any recent mutations that cause noticeable trouble, we can maintain our vital genetic diversity and human essence, permit the free flow of speculative evolution into the future, and yet counteract disease more effectively than if people died from it. Wnt (talk) 00:18, 29 June 2011 (UTC)

Agreed, and even if we do "fix such genes ourselves", that will probably fall to a different kind of natural selection. People's preferences as to what genes are desirable, and which are not, will change over time to fit current conditions and cause evolution that way. APL (talk) 03:00, 29 June 2011 (UTC)

How about a reference, here on the Reference Desk? Our article Human evolution includes the section Recent and current human evolution. Admittedly it is short, and I was surprised not to see a large article on this topic. PS: I have added an illustration of the creature into which we are evolving, according to a Russian scientist. Comet Tuttle (talk) 03:40, 29 June 2011 (UTC)

Man, that guy must have a strong neck. APL (talk) 06:46, 29 June 2011 (UTC)

Before we jump to conclusions that the skeleton of the Star Trek-like alien is the future of mankind, ask yourself this: Which segment of the population is growing faster? The ones with the really "big brains"? Or "everyone else"? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:33, 29 June 2011 (UTC)

Good point. What do you think is the correct answer to that question?

Here are some books that look at this question: Future Evolution by Peter Ward and Man After Man by Dougal Dixon. Both are good reads, Future Evolution is pretty dry and scientific, while Man after Man is really pure fantasy couched with scientific terms, but I found it fascinating nonetheless (although it wasn't as good as Dixon's other book After Man and unfortunately both of Dixon's books are rare and expensive). --Daniel 17:35, 29 June 2011 (UTC)

The people with the big brains reproduce much slower then everyone else, but when the formula for perpetual youth is discovered, then how many of the 12 kid families who live in the trailer park will be able to afford the youth elixer? Googlemeister (talk) 18:55, 29 June 2011 (UTC)

That is a good point, we can't take a current pattern that has only existed for a couple hundred years at most and assume it will continue for a million. Although Mike Judge's film Idiocracy imagines it continuing for a few hundred more. Even still, I don't think the trend is actually less intelligent people having more children, it is poorer people. --Daniel 19:02, 29 June 2011 (UTC)

I've seen this argument made, except... isn't it a general social law that the harder someone works, the less he makes? The poor people who breed the most may be undereducated and underprivileged, but I suspect in a truly fair assessment they are much more useful to themselves, their children, and humanity than all the wealthy CEOs and officials. In the long run, a humanity which replicates the qualities of the poor is sure to survive, but one based only on the rich would surely succumb to general madness. Wnt (talk) 23:19, 29 June 2011 (UTC)

Do people that live in trailer parks have smaller than average brains? I don't think so. I think I sense some kind of underground prejudice bubbling up to the surface. In fact, out of those 12 kids, the one with the largest brain might be the one that finds a better life while his "normal"-sized-brain siblings might end up in jail or dead. We don't know, but it is possible that trailer parks is exactly the place where evolution of larger brains is happening right now as we "speak". Dauto (talk) 20:43, 29 June 2011 (UTC)

Neanderthal had a larger brain then humans. Any guess on how well it turned out for them? Googlemeister (talk) 21:00, 29 June 2011 (UTC)

And whales have even bigger brains... But what does that have to do with human evolution? Dauto (talk) 21:58, 29 June 2011 (UTC)

Does sexual selection have anything to do with this? What I mean is that during hundreds of millions of years of evolution, animals have had to deal with fluctuations in selection pressure. If animals become tame too soon after predators vanish, they would have problems when the predators return. This problem could then lead to a selection pressure for sexual selection to lead to "survival of the fittest", even if you don't need to be fit to survive. Count Iblis (talk) 23:37, 29 June 2011 (UTC)

The number of young peoples deaths from firearms in America is high enough to exert a significant evolutionary pressure. I've been wondering if it will lead to better coping with the damage or a psychology to avoid the situations in the first place or what will happen. By the way the people with less children tend to be middle class rather than the rich or poor. Dmcq (talk) 00:20, 30 June 2011 (UTC)

Can you in any way back up your first assertion? --Tagishsimon (talk) 01:19, 30 June 2011 (UTC)

It's fairly well known I believe that one in a thousand difference in reproduction is enough to overcome genetic drift and exert evolutionary pressure and there seems to be something like 5 in a thousand such die from gunshot in the States I think. Car accidents would be in there too though not such a high proportion of young people are killed. Dmcq (talk) 08:20, 30 June 2011 (UTC)

Would 4 in 100,000 childhood deaths from firearms count? ^Avic_ennasis @ 21:57, 28 Sivan 5771 / 30 June 2011 (UTC)

I guess they mean about 15 years or less for childhood so that translates to about one in 1700 chance which possibly does matter even without considering the high young adult death rate, it wouldn't be a very strong effect though. Dmcq (talk) 20:19, 1 July 2011 (UTC)

They used 19 or younger. ^Avic_ennasis @ 03:30, 30 Sivan 5771 / 2 July 2011 (UTC)

Deep Tissue Massage

I was looking at the website of a day spa and one service they called "Deep Tissue Massage" which they described as "Is a type of massage therapy that focuses on realigning deeper layers of muscles and connective tissue." Realigning layers of muscle and connective tissue sounds like a bogus claim but if anyone has proof that it can really happen by one human's manual kneading I'd like to know.198.228.193.74 (talk) 22:17, 28 June 2011 (UTC)

Perhaps it helps just by stretching those muscles and connective tissue a bit. Even if those particular claims sound questionable, it still seems worthwhile, whether for psychological/stress-reduction/relaxation reasons or something else. StuRat (talk) 22:42, 28 June 2011 (UTC)

At $85 for 50 minutes, I'm pretty sure it couldn't make me feel good enough not to experience Buyer's remorse, but of course that's just me, and to each his own.198.228.193.74 (talk) 22:49, 28 June 2011 (UTC)

Oh, and I forgot to mention the primary benefit, working out all those farts inside you. Now you see why they charge so much. :-) StuRat (talk) 23:09, 28 June 2011 (UTC)

Another good one is "Reiki Healing," which says: "Japanese technique for stress reduction and relaxation that also promotes healing. It is administered by "laying on hands" and is based on the idea that an unseen "life force energy" flows through us and is what causes us to be alive" 70 bucks for 50 minutes. I'm in the wrong business.198.228.193.74 (talk) 10:54, 29 June 2011 (UTC)

There's probably also a keen distinction between "I do XXX because of the way it makes me feel." vs. "I do XXX because it makes me healthier" here. As long as XXX doesn't otherwise harm you, there's probably nothing wrong with "doing it because it makes you feel better", which as far as I am concerned, is a positive enough outcome even if outlandish health claims aren't backed up by hard science. --Jayron32 23:14, 28 June 2011 (UTC)

(But is it enough to trust the practitioner who makes the claims? I wonder this about chiropractics. Most of those chiropractic places have big banners advertising the health benefits of "laser massage" and other obvious flim-flam. Why would you let such a snake-oil salesman near your spine?) APL (talk) 02:04, 29 June 2011 (UTC)

The key phrase is "as long as XXX doesn't otherwise harm you". Its an important concept, and you should re-read my statement keeping that phrase in the forefront of your understanding of it. It is a conditional statement, and removing it from my writing above changes the meaning of it. It appears from your response that you inadvertantly removed that phrase when reading my writing, or ignored it, or otherwise didn't notice that I wrote it, so I thought it prudent to bring it to your attention again to assure that its full weight and meaning did not go unheeded. --Jayron32 02:39, 29 June 2011 (UTC)

Oh yea, I noticed it. And I wasn't trying to refute you or argue with you. I agree completely. I was just thinking 'out loud'. I was thinking of a situation where procedure XXX is known safe or low risk, but the local practitioners appear to be flim-flam men making insane claims. Since you can't actually know for sure if something will "otherwise harm you" before you do it, and afterwards the question is kind of academic. APL (talk) 02:56, 29 June 2011 (UTC)

Trudat. --Jayron32 03:04, 29 June 2011 (UTC)

You might like to follow up this site's reference. We also have an article on it: deep tissue massage. You might also like to look at Swedish massage. -- 17:45, 12 May2020 (UTC)