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May 23

Bodies of water silting up

Do we have an article that discusses the phenomenon of water becoming land as it silts up? I'm thinking of a pond that gradually fills with soil (I'm writing an article about a cemetery whose sexton intentionally did that to a pond, since mowing a little extra grass was cheaper than keeping a pond), or of an estuary that gradually becomes floodplain; I checked Wigtown, where the latter happened, but I found nothing relevant. Siltation (to which silting redirects) is related, but it really doesn't care about much other than silt pollution; I was hoping for something more closely related to the process of filling in a watered area, but can't find anything. Nyttend (talk) 02:28, 23 May 2013 (UTC)[reply]

I believe this is called Deposition (geology). The Wikipedia article only covers coastal deposition in any detail, but I got to that article from River delta, which is basically what you're talking about, river deltas form by a natural silting process that you're talking about. Deliberately filling in bodies of water is called "landfill" (different definition from the place where you bring your trash) and the Wikipedia article that covers it is called Land reclamation. --Jayron32 03:22, 23 May 2013 (UTC)[reply]

Actually, the succession of plants in such areas may have more to do with the transition from open water to dry land than does siltation per se. You may find the article Hydrosere of interest. Deor (talk) 12:40, 23 May 2013 (UTC)[reply]

Validity of the ideal gas law

For what temperatures and pressures is the ideal gas law a valid approximation? — Preceding unsigned comment added by 130.56.81.186 (talk) 04:31, 23 May 2013 (UTC)[reply]

What did your teacher say when she taught you this in Chemistry class a few days ago? -Jayron32 04:36, 23 May 2013 (UTC)[reply]

The various gas laws, such as Boyle's law, Charles's law and the ideal gas law, were discovered over a century ago by scientists whose experimental equipment was very rudimentary by modern standards. These scientists were only able to investigate the behavior of gases at pressures close to atmospheric pressure, and temperatures close to those found on the Earth's surface. These gas laws are valid at around one atmosphere (low pressure) and typical terrestrial temperatures. At very high pressures and very low temperatures, gases begin to behave a bit like liquids so the various gas laws become increasingly inaccurate. Dolphin (t) 06:28, 23 May 2013 (UTC)[reply]

Actually, it is quite wrong to say the approximation works around atmospheric pressure and is les good far from it. What is important, for the ideal gas laws to be a good approximation, is to be sufficiently well away from the vapour saturation line (a curved line from the high triple point to the liquid/vapour critical point, plotted on a graph of temperature vs internal energy - a line where to the left of it the substance is a mixture of liquid and gas, and to the right of it is purely a gas). The critical point of any substance is where the specific heat of the substance as a gas becomes infinite. The triple point is the temperature and pressure at which liquid, solid, and vapour phases co-exist. Plotted on a graph of temperature vs internal energy, the triple point is a straight line, stretching from the Low Triple Point (min internal energy) to the High Triple point (max internal energy). Lines of constant pressure can be plotted on a temperature vs internal energy graph as contours. These contour lines are straight diagonal lines well the the right of the vapour saturation line, and increasingly curve towards the horizontal as they approach the vapour saturation line, abruptly changing to the horizontal just at the VSat line near the triple point, transitioning to a gradual curve that is horizontal at the critical point. Where the constant pressure lines are straight diagonals is where the substance behaves as an ideal gas.

For water, the critical point is 647.1 K and 22.064 MPa, and the High Triple point is 273.16 K, 611.7 Pa, and 54.01 MJ/kmol, and water (steam) will not behave as an ideal gas at atmospheric pressure. For oxygen, critical point is at 154.58 K & 5.043 MPa; High Triple Point is at 53.36 K, 146 Pa & 7.315 MJ/kmol. Other substances have very different triple and critical points, at higher and lower temperatures, and higher and lower pressures. A few gasses follow the gas laws pretty good at ordinary temperatures and pressures, many do not. The NIST-JANAF Thermochemical Tables, published as Monograph 9 by the Journal of Physical and Chemical Reference Data, gives full details in tables for a hundreds of common substances. Any good university library will have it.

Wickwack 121.221.2.127 (talk) 07:16, 23 May 2013 (UTC)[reply]

Will you get the course credit instead of this student for performing his work for him? I don't really need to pass general chemistry again, which is why I directed him to review what his teacher taught him... --Jayron32 12:36, 23 May 2013 (UTC)[reply]

It's not entirely clear whether this homework or not. Not a very good question for a home work since it implies the incorrect notion that there is a specific set of temperature and pressure for which the law works (or doesn't work). Wickwack's answer makes that point clear and therefore was an appropriate response. Dauto (talk) 17:28, 25 May 2013 (UTC)[reply]

The ideal gas law is, as the name suggest never precisely valid, it is only valid in the limit where the molecules in the gas don't interact any more and where the gas becomes infinitely dilute. These are two independent conditions, the former is quite obvious, the second has to do with quantum effects. Even if you have an ideal gas w.r.t. to the first condition, i.e. a gas consisting of hypothetical moleculs that don't interact with each other at all, you will still have deviations from the ideal gas law due to quantum effects. These deviations only tend to zero in the limit that the density of the gas tends to zero.

In practice, the devations from the ideal gas law due to the interactions of the molecules are seen in the conditions mentioned by Wickwack above. Quantum effects that cause significant deviations from the ideal gas law are seen in practice in extreme high density matter. E.g. certain types of supernova explosions are triggered due to a star having run out of fuel, contracting as a result causing the temperature and density to go up again and then fusion starts again. But the fusion then starts in matter that is so dense that the ideal gas law isn't valid, the pressure does not depend on the temperature anymore. This independence of the pressure on the temperatre causes a supernova explosion. This is because the rate of fusion reactions increases very rapidly if the temperature increases. Then an increase in the rate of fusion reactions would lead to more heat being generated and to even higher temperatures and therefore much higher fusion reaction rates. What stops such a runaway increase in reaction rates in a normal star like the Sun, is the increase in pressure of a region at higher temperatures which causes such a region to expand and become cooler due to performing work. Count Iblis (talk) 13:00, 23 May 2013 (UTC)[reply]

Is there any scientific evidence about spirits and their ability to affect the living?

Resolved

I am from Asia, where almost everyone around is very superstitious. What they do all the time is praying for some blessing of the gods rather than relying on themselves. I only trust myself, but there was an event occurred in a nearby village (just hundreds meters away) that troubled me. The story is long but I'll keep it as short as possible.

The villagers noticed that many adults in the village had died rapidly in the last few years. All death were quick (like traffic accident) and sometimes mysterious (had an unknown fever and died). A shaman said that it was a female ghost that did all the tragic (maybe she loved these guys, lol?). The villagers decided to raise big funds (just around $3000, but it was very big in my country) to hire a local monk and 6 famous shamans which came from far away to perform the ritual, in the hope of stopping the tragic. The ritual took place just a few days ago, with the observation of hundreds curious people.

I was not at the event, but according to my mother, their work was to met the ghost, ask her about the reason and to negotiate with her. The ghost did come, and possessed a female local villager. It turned out that the ghost was male, and he claimed that he had lived in that village for 320 years! According to him, the village road was 6 meters wide, with daisies on the 2 sides. But the villagers expanded their houses to "his road", and now the road was only 4 meters wide, causing movement difficulties for "his horses and elephants". He said that he let "his horses kick and his elephants stomp" the villagers to their deaths. He demanded the villagers to break their house wall, and return 2 meters for his road. I thought that the dead can fly, but this one need a wide road to walk. Funny, right?

The ritual to call the deceased to possess a living is performed frequently in my place, mostly for those who died suddenly, to ask them about their wishes. Some do not even need a ritual, they can do it by themselves. The wife of my grandfather's brother, for example, she possessed her son's wife on the 50 and 100 day anniversary of her death (yes, twice).

To this days, I still don't believe these stupid things much after all. Does science ever acknowledge the existence of these entities and their ability to affect the living? Or is there any study or result about this subject? -- Livy (talk) 05:14, 23 May 2013 (UTC)[reply]

No. --Jayron32 05:16, 23 May 2013 (UTC)[reply]

Science doesn't even understand how we possess our own bodies, never mind somebody else's. Gzuckier (talk) 06:03, 23 May 2013 (UTC)[reply]

I completely agree with Jayron32, but I think more can be said, I think Gzuckier's answer is a flat copout, science does have a lot to say about how we posses our own bodies, for one, we can be fairly certain it involves our physical brain..> Back to the OP, firstly, congratulations for having some skepticism in a place where you are steeped and surrounded in such incredible events. In the west, there has been an old and strong tradition of people who have challenged these ideas and beliefs and examined them very closely. From Harry Houdini to James Randi, they challenge people to demonstrate these abilities under controlled conditions and for the last century, not a single person has been able to give any compelling evidence that their powers or abilities are more then just psychological "tricks" and illusions and a lot of the time just plain fraud almost identical to methods used by stage magicians. Vespine (talk) 06:07, 23 May 2013 (UTC)[reply]

No, Gzuckier is right — science has nothing to say, and will never have anything to say, about how "we" possess our bodies. The materialist explanations amount to denying that there is any such thing as "we". Science can tell us a lot about how our brains control our bodies, but that's a different topic altogether. --Trovatore (talk) 06:27, 23 May 2013 (UTC)[reply]

No, you have nothing to say about how we possess our bodies. Neither do today's scientists, because nobody understands consciousness in a meaningful way. To claim that nobody who will ever be born in the trillions of years to come will figure it out is pure hubris. If and when somebody eventually understands consciousness, I guarantee that it will be through science (just like every other discovery about the natural world), not religion, mysticism, or making stuff up. --Bowlhover (talk) 09:15, 23 May 2013 (UTC)[reply]

The attempted explanations thus far do not fail for some correctable reason, some "oh, well we didn't quite close that last gap" kind of thing. They are category errors. They are attempting to explain the externally observable correlates of consciousness, not consciousness itself. I don't see how science, as it is currently construed at least, can ever get past that hump, even in principle, because science almost by definition limits itself to the externally observable. However, I am willing to concede that there is no really complete definition of science, and it is imaginable in principle that some future intellectual discipline that does not limit itself to the externally observable, but that is nevertheless somehow recognizable as "science", could have something to say. --Trovatore (talk) 17:06, 23 May 2013 (UTC)[reply]

Indeed. We're at a state now, where we can isolate muscle tissue and cause it to do mechanical work in vitro. We can put kidney tissue on a filter and make it transport water. We can take out a pancreas and put it in a dish and stimulate it to produce digestive enzymes and/or insulin. Etc. But I'm pretty sure nobody's ever taken out a brain, put it in a dish, and produced consciousness. I'm not a kook; I'm as materialist in this issue as most everybody is these days. I understand that consciousness etc. is somehow emergent from the function of the brain. But we are so far from explaining it, that we can't even see what direction to start off in. We can't even agree how to prove consciousness from communication or otheer behavior which resembles precisely the product of consciousness, if we can't directly see that it's coming from a human. We can't even prove it when it does come from another human, except by induction and generalization from our own internal case, as you point out. Gzuckier (talk) 05:34, 24 May 2013 (UTC)[reply]

Well, my position is a bit harder-core than that. I do not think the hard problem of consciousness has a materialist solution at all. --Trovatore (talk) 06:08, 24 May 2013 (UTC)[reply]

There is much study of the paranormal. see Paranormal#Skeptical scientific investigation. Many people and organizations who don't believe in spirits and the supernatural have offered substantial prizes to see if anyone can demonstrate, with scientific thoroughness, the existence of these things. See List of prizes for evidence of the paranormal. (None of these prizes has been claimed!) James Randi is a famous person who has exposed various paranormal claims as being nothing but trickery. Dolphin (t) 06:15, 23 May 2013 (UTC)[reply]

Yes, there is plenty of evidence that spirits, if they were to exist, cannot interact with us to give rise to the effects that are commonly attributed to them. Basically, it boils down to such effects violating the known laws of physics, and that there is a huge amount of evidence for those laws of physics. This means that if you were to take up the Randi challenge as mentioned by Dolphin and Vespine above and were to prove that a non-trivial effect does exist, it would be similar to proving that somehow Copernicus was wrong and that the Sun does revolve around the Earth. But, of course, just like you can always put the idea that Copernicus is wrong to the test, you can also put the claims of psychics etc. to rigorous tests in the laboratory.

Uri Geller in the 1970s did put himself through some tests, because he knew how he could deceive naive scientists. Randi criticised these tests for being too naive but at the time he was ignored for being a radical sceptic. Randi then proved his point by letting two magicians present themselves as psychics and let them go through the same tests. When it was reveiled later that they were just magicians, Randi's objections were taken serious. One mathematician who was involved in testing Geller who until that point was a strong believer in his abilities then thought that he could just invite Geller back for the same tests, but now he would make sure the spoons would be labelled. However, Geller did not want to be tested anymore :) . Count Iblis (talk) 11:42, 23 May 2013 (UTC)[reply]

2 years ago many of my relatives met a shaman for calling the spirit of my mother's sister' husband. He first possessed his own wife (my mother's sister), then switch to the shaman herself. I cannot tell if it was him or the shaman talking us but the shaman knew every people in my family, and even who had attended his funeral! It is incredible... Is there any spirit possession ritual or the like in the West? -- Livy (talk) 06:51, 23 May 2013 (UTC)[reply]

Yes, it's called cold reading. Vespine (talk) 06:59, 23 May 2013 (UTC)[reply]

See Spiritualism. --TammyMoet (talk) 11:43, 23 May 2013 (UTC)[reply]

The shaman could have deceived us, true. But what about the case of the wife of my grandfather's brother? She possessed her own daughter-in-law. The daughter-in-law was very scared and tired after being possessed for the first time on the 50 day anniversary at her mother in law's house, and she vowed not to attend the 100 day anniversary. My mother's sister (the one mentioned above) laughed and told us that she could not avoid the inevitable. For some odd reason, she ended up in the local pagoda where we perform the ritual on that day (after the ritual in the house), and being possessed for the second time. She even hit 2 of her mother-in-low's sons. When we asked her whether she remembered what she had said and done, she told us that she did not know anything, but felt heavily exhausted. I tell myself not to believe, but it is really weird. -- Livy (talk) 15:10, 23 May 2013 (UTC)[reply]

In the West, we usually refer to instances of such behaviour as being indicative of a mental disorder, such as Dissociative Identity Disorder. Ockham's Razor tells us "that entities be not multiplied save of necessity", and we find it unnecessary to invoke any other beings apart from ourselves to explain our own behaviour. --TammyMoet (talk) 15:32, 23 May 2013 (UTC)[reply]

Certainly the answer here is a clear and unambigious "NO!". Science has zero evidence for ghosts or spirits or whatever.

While it is true that we don't understand every last detail of how human consciousness works - we do know enough to put limits on what it can do. We know, for example, that it resides in the brain - that it's the result of neural interactions - that it's bounded by the regular laws of physics - consciousness doesn't violate the conservation laws or the laws of thermodynamics. The main reason we can't say more about it is that there is no good definition of what the word "consciousness" actually means. If we had a solid definition for that word, we'd have an answer soon afterwards.

To use an analogy: I don't know the location and species of every plant that's growing in my back yard...but that doesn't mean that there can be 10' tall rampaging carnivorous plants out there! Just because you don't know every detail - doesn't mean that you know nothing.

If there really were ghosts or spirits, science would certainly have noticed large, measurable and unexplainable differences in very simple science experiments...and we don't. If all of that existed, surely the ghost of some scientist would have made his presence known by repeatedly disrupting some kind of science experiment in such a way that the experimenter would have no choice but to notice. This has never happened. Some people such as Harry Houdini have promised that if they ever find themselves in the spirit world, then they will communicate an otherwise secret message in order to prove that fact...they never have.

SteveBaker (talk) 16:01, 23 May 2013 (UTC)[reply]

The West and the East do have very different cultural perspectives. ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 16:04, 23 May 2013 (UTC)[reply]

The Eastern ghost isn't the Hollywood-like ghost figure or the one Michael Jackson sings about. ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 16:04, 23 May 2013 (UTC)[reply]

They certainly do have different cultural perspectives...but that has no relevance here - we're being asked about whether science has evidence...that's way, WAY different from what a bunch of non-scientist have decided might be true based on some cultural hand-me-down from their ancestors. SteveBaker (talk) 19:14, 23 May 2013 (UTC)[reply]

One thing you can do is go watch some good magicians, specifically mentalists. They do many seemingly impossible things. That can explain the shaman, but doesn't explain your relative's experience. For that, I would read about cases like Clever Hans. Another thing thing you have to realize is that your own memory and perception are also be flawed. Things you remember happening, might not have happened precisely how you remember them. Because these events happen under conditions which are not at all controlled, you can not know what other people know or might be doing. When psychics are studied carefully, their subjects can claim something like "the psychic knew my dead uncle's name" and be adamant that this was the case. But if the session was recorded, what you'll find is that the "psychic" might have said something like "I'm getting a name, John or Jason?" subject: "no". Psychic: "actually, maybe Rob, or Bob, Robert? Maybe Rupert" The subject says "yes, I knew a Robert", Psychic: it was someone very close to you, a fatherly figure, someone you looked up to, your grandfather, maybe uncle?" and the subject says "Yes Robert was my uncle!!" and they are amazed at the psychic's ability. After another 30 minutes of talking, all they remember is that the psychic guessed their dead uncle's name was Robert, but they'll completely forget the process that it took to get there. After they will tell their friends that the psychic amazingly guessed their dead uncle's name. Vespine (talk) 23:24, 23 May 2013 (UTC)[reply]

Also, you might find Committee for Skeptical Inquiry interesting. Vespine (talk) 23:25, 23 May 2013 (UTC)[reply]

It is clear that I have found the answer to my question. There is no scientific evidence about these entities. Although everything happens in my place is very weird and hard to find appropriate answer, but until there is scientific evidence, I will not believe anyone rather than myself. Thanks to you all for your useful information, and hopefully science can give appropriate explanations for these mysterious phenomena someday! -- Livy (talk) 12:19, 24 May 2013 (UTC)[reply]

I don't think this is really "resolved" at all. Consider a human brain that contains one or more so-called "conscious minds" and "subconscious minds", even "multiple personalities". What sets the limits of where a personality begins and ends? What rule says that the domain of brain held by something that perceives itself to be "a person" must be held entirely within a single brain, rather than existing, for example, in a network of communication and written folklore held within the people of a village? Why can't a dead person's consciousness be continued, in part, in the brains of living persons who have absorbed some of his way of thinking? When we speak of mind rather than brain, when we speak of sensations of existence rather than neural pathways, the science seems very weak. I would suggest that it is accurate to speak of overall conserved algorithmic features in terms of an atman, which recognizes the continuity of living and dead; and thereby the reality of reconstruction of the departed "individual" whenever we pay attention to attempting to reconstruct key influences of the personality. But this is also very similar to saying that the practice is delusion, a heuristic meant to seek artistic inspiration (well, more like engineering inspiration, but we don't have an article on that) via a ritual which, though not scientifically meaningful, has the potential to inspire the imagination. I'm afraid the methods of science dissolve into philosophical confusion outside its proper domain. Wnt (talk) 07:17, 25 May 2013 (UTC)[reply]

My question was "is there any scientific evidence", not "do these entities actually exist". If it were the later, this question would raise controversy and never end. But it is the former, and the answer is clearly "no". :) -- Livy (talk) 01:16, 26 May 2013 (UTC)[reply]

Threr some people who hear them, there are people who feel them , and see that they move things, But they ignore you, It's a bit like a computer and humans, the computer does not feel, and people can move things without him , Thanks --81.218.91.170 (talk) 15:01, 27 May 2013 (UTC)[reply]

Measuring roughness

Is there a good way of measuring how rough or smoothly varying a surface is? I have data fields specified as T(x,y), and I'd like a way to quantitatively distinguish fields that change gradually as one varies x and y from those that vary rapidly. In both cases the overall change is generally bounded, so there isn't a lot of net change over long distances, but some vary much more over short distances than others. Viewed as an image, you might say some fields are noisy while others are smooth. I'd like to have a good way to quantify these differences. What are some standard techniques / measures that people use to describe the roughness (or noisiness) of a field? Dragons flight (talk) 06:46, 23 May 2013 (UTC)[reply]

Roughness of data, and roughness of a physical surface, is commonly measured/expressed as the Root Means Square (RMS) roughness. You take the error from the mean or ideal value for each data point, square it, and calculate the average of all the squares, and take the square root of that. In mechanical engineering, it is called RMS roughness. In statistics and for numerical data generally, it is called the standard deviation. Wickwack 120.145.149.52 (talk) 07:41, 23 May 2013 (UTC)[reply]

Wikilink - Surface roughness seems to give a fair bit of maths to help you out. 80.254.147.164 (talk) 08:48, 23 May 2013 (UTC)[reply]

An RMS measure that considers only the deviation from the mean is poor indicator of roughness and doesn't really correspond to human perceptions of roughness either. Consider the two diagrams:

  ---
--   ---   --
        ---

 -   -   -
- - - - - - -
   -   -   -

Those examples are identical from an RMS perspective, but one surface would generally be perceived as varying more rapidly than the other. It is cases like that for which I am looking for a natural way of quantifying that the top panel experiences gradual change and the lower panel undergoes rapid change. Dragons flight (talk) 09:36, 23 May 2013 (UTC)[reply]

Actually, the RMS deviation or standard deviation value does correspond to the human "feel of it" pretty well, and is usually the most useful mathematically in most applications. However, if what you want is an indication of rate of change, then I suggest that you do a discrete fourier transform over the extent of the surface (in other words, treat the surface as regularly repeating segments, each of size equal to the surface in question. The result will be a a histogram of frequencies, and make the most significant frequency immediately visible. You can then weight the frequencies and calculate an RMS or mean value of them, to taste. This value will reflect both ammplitude and rapidity of change. Wickwack 120.145.149.52 (talk) 10:39, 23 May 2013 (UTC)[reply]

A simpler approach is to calculate the slopes (T/x) between data points, weight them according to peak-to-trough amplitude,and take the RMS value of all the weighted slopes. Wickwack 120.145.193.132 (talk) 11:44, 23 May 2013 (UTC)[reply]

How you quantify roughness usually depends on why you need to know it, or how you want to use it. So if you tell us more, we might have better suggestions. Other potential choices come from fractal analysis, such as the box-counting dimension, or the Hausdorff dimension. SemanticMantis (talk) 15:53, 23 May 2013 (UTC)[reply]

Also, are these continuous functions, or just point sets? For instance, rugosity might be a nice measure for the former, but not defined for the latter. SemanticMantis (talk) 16:10, 23 May 2013 (UTC)[reply]

is there a difference between "roughness" and "coarseness"?68.36.148.100 (talk) 02:54, 24 May 2013 (UTC)[reply]

Yes - definitely. Roughness is a term applicable when a surface has random or random-like variation. Coarseness is the term to use when the variation is not random but is associated with grain. For example, a polished metal surface that has then been etched with acid typically has random variations in its surface - so we speak of its roughness. A woven cloth may have a rough feel, but its variation is essentially periodic, not random, due to the weave - so we speak of its' coarseness. In metal working, the surface variation may also be periodic, due to the sequential action of a machine tool, or it may be random-like due to the action of hand-operated sanding. However machine sanding or grinding may impose a grainy finish. In these cases it is a matter of judgement whether the terms roughness or coarseness should be used, but both are measured in the same way - the RMS deviation from true. See any good dictionary. Wickwack 121.215.134.76 (talk) 03:13, 24 May 2013 (UTC)[reply]

or I could just see your answer. From your answer I wonder why they are not mentioned anywhere in wiki as being so closely related as you say68.36.148.100 (talk) 03:47, 24 May 2013 (UTC)[reply]

You shouldn't just trust me, or any contributor on this forum. You should consult a good dictionary. My role is only to point you in the right direction. Wikipedia articles are not perfect. They are not expected to be. Many are good. Some are very very good. Some are rubish. You could register as an editor, get a username, and improve the roughness article by including a comparison with coarseness and graininess, thereby making your contribution to help the World. Most likely the reason it isn't there now is because the volunteer editors didn't think of it. I've chosen not to edit articles. Wickwack 121.215.134.76 (talk) 05:32, 24 May 2013 (UTC)[reply]

I have chose not to edit either. But to point the editors in the right direction.165.212.189.187 (talk) 13:17, 24 May 2013 (UTC)[reply]

The most convenient and frequently used way to characterize surface roughness is by measuring its Power spectral density function. Ruslik_Zero 19:30, 24 May 2013 (UTC)[reply]

You might also want to look into Hurst exponent. Quote from the article: "H is directly related to fractal dimension, D, where 1 < D < 2, such that D = 2 - H. The values of the Hurst exponent vary between 0 and 1, with higher values indicating a smoother trend, less volatility, and less roughness." Dauto (talk) 13:35, 25 May 2013 (UTC)[reply]

global warming referred to in article - is this statement up to wiki standards?

page: Stirling Range (Australia)

This contributor throws a climate change reference and state climate change makes short-term gauges unreliable. Is this a fact or an opinion? Is this a credible statement that Wikipedia can stand behind?

I deleted the reference but editors constantly undo my change. The statement is pasted below from the page (last sentence, I put an arrow point to it).

However, it is believed that rainfall on the peaks near Bluff Knoll may be as high as 1100 millimetres (43 inches), a hypothesis supported by the existence of distinctly moist-climate pockets of vegetation in some high valleys. Because no rain gauges have ever been placed on the high peaks ' ----> (climate change since the late 1960s makes short-term gauges unreliable anyway) we cannot be sure of this.'

Thank you!

montana2021 — Preceding unsigned comment added by Montana2021 (talk • contribs) 15:03, 23 May 2013 (UTC)[reply]

That is obviously a "non-obvious" fact - and it needs a solid reference - especially if other editors find it controversial enough to want to remove it. So, you need to find a document, acceptable to WP:REF that says essentially just that. If you can, then the other editors should back down and allow that statement to stand...if you can't, then they are quite justified in removing it. SteveBaker (talk) 15:20, 23 May 2013 (UTC)[reply]

Thanks for your help! I feel helpless in seeing the hyper-political climate change believers polluting so many wiki articles. — Preceding unsigned comment added by Montana2021 (talk • contribs) 15:36, 23 May 2013 (UTC)[reply]

I think you might do well to read our articles on climate change, and on global warming - they aren't the same thing. As for your suggestion that "hyper-political climate change believers [are] polluting so many wiki articles", we base articles on published reliable sources, not our own beliefs - and since the overwhelming consensus amongst scientists within the relevant fields is that anthropogenic global warming is a real phenomenon: in consequence, where relevant, and where properly cited, our articles may reflect this. AndyTheGrump (talk) 17:13, 23 May 2013 (UTC)[reply]

Indeed. The exceedingly well referenced fact of climate change isn't even the issue here - it's the question of whether that makes short-term rain gauges unreliable (reference needed) and whether that has any relevance whatever to the lack of good information about rainfall on these peaks (reference needed). I can't see why that would be so it's not obvious and it's certainly a fact that's likely to be disputed (I'm disputing it!) - so it needs a reference or we should delete it. SteveBaker (talk) 19:11, 23 May 2013 (UTC)[reply]

Why do East Asians, particularly Chinese people, dominate at table tennis?

As usual, in the 2013 World Table Tennis Championships the Chinese did very well. Only a few other East Asian countries offered some competition. Participation from Western countries is dominated by Chinese immigrants. Is there a biological reason why East Asians, particularly the Chinese are better at this game than people from other countries? Count Iblis (talk) 16:21, 23 May 2013 (UTC)[reply]

Is there a biological reason why the Chinese seem to produce few good cricketers? AndyTheGrump (talk) 16:29, 23 May 2013 (UTC)[reply]

I see no reason to suspect a biological reason. Table tennis is popular in China and they have a lot of players. Some of them are bound to get good, and some of them take the sport to other countries. The cost and space requirement of a sport can be a big factor in how widespread it is. Most Chinese are poor by Western standards and table tennis is cheap. Tennis is more expensive, requires more space, and China has few good players. PrimeHunter (talk) 16:42, 23 May 2013 (UTC)[reply]

It's almost entirely likely to be cultural. People from different cultures enjoy different foods, make and listen to different music, and enjoy different leisure activities. Those differences are indeed what makes them different cultures in the first place! It doesn't prevent people from other cultures from participating in those activities, but broadly speaking, since you find less people from other cultures participating, you find less people from other cultures participating at the highest level. This has nothing to do with any genetic superiority of an entire race, ethnicity, or culture group and more to do with the arbitrary (but still real) differences between cultures. --Jayron32 17:54, 23 May 2013 (UTC)[reply]

Ping-pong diplomacy is a nice read, and there are several documentaries floating around the web about municipal table tennis tables being erected in China. Per Jayron, I think it's cultural, and nothing to do with the biology of people from Asia. The same could be said of badminton. The Rambling Man (talk) 18:05, 23 May 2013 (UTC)[reply]

The Mayor of London, Boris Johnson gave a rather splendid speech to the British team at the Beijing Olympics, stating that other while nations saw the dining table as an opportune place for a good meal, the British saw it as an opportunity to invent a new sport, originally called "Wiff-waff".[1] Sadly, we don't seem to be terribly good at it. Alansplodge (talk) 22:42, 23 May 2013 (UTC)[reply]

The British are evidently neither cunning nor short enough. μηδείς (talk) 00:58, 24 May 2013 (UTC)[reply]

Ha, so there actually is a biological reason why the British don't do well in this sport! Count Iblis (talk) 17:39, 25 May 2013 (UTC) [reply]

May 24

Chicken game

I can't seem to find in the article the outcome of both drivers swerving but into each other anyway (a real life situation that many consider when playing). Or even in the case of the bridge scenario both crashing into the ravine. Which made me think of another scenario: both swerving but only one crashing into the ravine. Are these scenarios not considered to simplify the game? Are there other games in which these scenarios are relevant ?68.36.148.100 (talk) 02:43, 24 May 2013 (UTC)[reply]

The Game Theory scenarios of Chicken are highly simplified. They don't consider every possible outcome, like "swerving and hitting an innocent bystander" or "swerving and clipping the other driver so he crashes but you do fine" or anything else like that. It really only considers what happens in 4 possibilities: Both swerve, I swerve, you swerve, and no-one swerves, with the inherent assumption that swerving always leads to safety. It's used as a model for human behavior, not as a comprehensive analysis of the actual game of chicken. --Jayron32 03:22, 24 May 2013 (UTC)[reply]

So you answers are yes and .......? And an actual game of chicken is not a good model of human behavior?68.36.148.100 (talk) 03:25, 24 May 2013 (UTC)[reply]

It seems reasonable that both drivers would agree in advance to swerve either right or left...and I very much doubt that playing it in a ravine or on a bridge or anything like that ever really happened. But there are obviously cases where people swerved - but to late to avoid some sort of vehicular contact - and the results of that could be anything from "trading paint" to death of both drivers. SteveBaker (talk) 03:58, 24 May 2013 (UTC)[reply]

Then shouldn't the rules of the game be augmented to include such important details and avoid confusion as to the rules? "OK, I hate your guts but make sure you swerve to the right - deal?" (the adversaries trustingly shake hands) 165.212.189.187 (talk) 13:31, 24 May 2013 (UTC)[reply]

(edit conflict) I suppose it could be, but that's not how Game theory is being invoked here. Game theory is a branch of behavioral sciences that deals with human interactions where two people have a choice on how to behave, and looks at how the perception of the outcome of the choices of the participants feeds back to influence actual choices. The "Chicken" game is merely the name given to a mathematical model of any scenario where two participants have to make a binary choice, and where the four outcomes are "lose huge-lose huge", "win little-lose little" "lose little-win little" and "tie-tie". The name of this as "The Chicken Game" in Game Theory is merely a bit of whimsy, as the four outcomes roughly mirror the basic outcomes of the classic game of "Chicken", but that's not the important thing about the game. It's the four outcomes that makes this a particular "class" of scenarios in Game Theory, it's one of the more famous Game theory models as it comes up again and again (see the article for the "Hawk-dove" model where it looks at the outcomes of deciding between being a "Hawk" (favor war) or a "Dove" (favor peace), and thus can be used to model how politics works in tense situations between states. These sorts of scenarios help model human behavior because they help to establish what is known as a Nash equilibrium, which attempts to predict what each person in the scenario is likely to do given that each also knows what the other is most likely to do. The "Chicken" game is an unstable equilibrium, because the only decision that leads to a "win" also leads to "lose huge" exactly 50% of the time, and each participant knows that the other participant knows this as well. --Jayron32 04:00, 24 May 2013 (UTC)[reply]

Thanks, I get that "chicken game" is a superficial name for the real theory. So can someone answer my second question? Are there other games where in addition to the four choices there are also the extra ones that I mentioned?165.212.189.187 (talk) 13:13, 24 May 2013 (UTC)[reply]

Yes, there are game theory style models for much more complex scenarios. For example, in finance, many people use Pareto optimality to demarcate a line of equilibrium outcomes in a high dimensional choice space. As the scenarios become more complex, and participants have more options and more possible outcomes, it becomes harder to describe in a few simple terms, like "playing chicken." Nimur (talk) 13:23, 24 May 2013 (UTC)[reply]

See Spherical cow for the general idea. One should normally make a problem simple to analyse it and only stick in extras if the simple model turns out to be inadequate in some way. Having just the one choice for each person in chicken is adequate for analysing the basic problem. Dmcq (talk) 15:57, 24 May 2013 (UTC)[reply]

interference

What is the reason for interfernce112.79.41.16 (talk) 03:33, 24 May 2013 (UTC)?[reply]

What type interference? Have you read the articles? Plasmic Physics (talk) 03:40, 24 May 2013 (UTC)[reply]

I presume you're talking about radio and TV interference? In which case you should read our Electromagnetic interference article.

Strictly, interference comes about from having two or more transmitters working on the same frequency (or frequencies very close to each other). That can happen (for example) when two radio stations in different parts of the world use the same frequency because they imagine that they are far enough apart for the interference to be bearable...but when optimal weather conditions allow the signal to travel further than usual, you get interference. But there are many other possibilities. Most electronics emit some stray unintentional radio waves - and that can interfere with legitimate transmissions. Sunspots and aurora phenomena can also generate radio waves...microwave ovens, power transmission lines...you name it! SteveBaker (talk) 04:04, 24 May 2013 (UTC)[reply]

And if you get too close to a radio transmission tower, it can bleed over into other frequencies. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:13, 24 May 2013 (UTC)[reply]

Also most modern radio and t.v. sets are poor quality receivers, they can't be used to recieve weak signals they are very susceptible to odd order intermodulation effects etc. Good quality radio receivers like the NRD535 are no longer sold. Count Iblis (talk) 13:32, 24 May 2013 (UTC)[reply]

Much of the interference which bothers radio listeners and television viewers comes from alternating current electric power transmission and distribution lines, along with ham radio transmitters, as well as the make-break of heaters such as those on aquariums, electric blankets , and defective doorbell circuits. I've also seen severe TV interference resulting from two utility ground wires, actually at slightly different potentials relative to earth ground, which were rubbing against one another. Additional interference (other than distant intentional terrestrial transmissions) might come from lightning. Edison (talk) 03:21, 25 May 2013 (UTC)[reply]

Are there giant rats of about 90cm large?

Just in a novel I see that on Mongolian grassland there is a giant rat of 90cm(3ft) size and can kill a cat. Is this a exaggeration? Or are there other animals of this size but might be recognized as a rat?--Funtkd (talk) 06:55, 24 May 2013 (UTC)[reply]

We have an article on the subject (of course): Giant rat. The very first entry is the Gambian pouched rat, which states it can grow up to about 90 cm. A specimen of another species,[2] found in 2009, measured 82. Of course, that's nothing compared to the Giant rat of Sumatra. Clarityfiend (talk) 07:27, 24 May 2013 (UTC)[reply]

Also known as "R.O.U.S. (Rodents of Unusual Size)," or "ROUSes". ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:05, 24 May 2013 (UTC)[reply]

The Capybara is the largest rodent. Adults are over a metre. --Fama Clamosa (talk) 15:44, 24 May 2013 (UTC)[reply]

There are several species of very large rats out there - there are various "pouched" rats that are that large, but none of them live anywhere near Mongolia. The only Asian giant rats live in Indonesia and New Guinea. Even if we imagine this might have been some kind of invasive species, those large rats are omnivorous - but the only animals they eat are invertebrates, snails and small crabs. It doesn't seem likely that they'd kill something the size of a cat - except possibly in self-defense. Since this was a novel, I think it's safe to assume that the author invented this species to help out the plot. SteveBaker (talk) 16:01, 24 May 2013 (UTC)[reply]

Matilda Briggs was not the name of a young woman, Watson, ... It was a ship which is associated with the giant rat of Sumatra, a story for which the world is not yet prepared. Gzuckier (talk) 16:38, 24 May 2013 (UTC)[reply]

Can Minkowski's addition to Special Relativity be experimentally supported / disproved?

HOOTmag (talk) 06:59, 24 May 2013 (UTC)[reply]

It's not clear to me what precisely you're considering to be Minkowski's "addition" to special relativity. Minkowski came up with Minkowski space, which is a convenient mathematical framework in which to express special relativity, but that's not really an "addition" to special relativity in terms of additional physical hypotheses, i.e. any new physical theory, it just provided a convenient mathematical framework in which to express the existing physical theory. So there was nothing new to experimentally test. Red Act (talk) 14:18, 24 May 2013 (UTC)[reply]

How much electric shock can cause permanent tissue damage?

The Milgram experiment used shocks up to 450 volts and says "Although the shocks may be painful, there is no permanent tissue damage". I know that duration and place also matters, but just see what is available.--Funtkd (talk) 07:00, 24 May 2013 (UTC)[reply]

Wouldn't the amount of amperes be of more importance than the voltage when it comes to causing damage - at least our article on electric shock keeps talking about amperes and not volts when it comes to tissue damage. It does note however that voltages of 500V to 1000V can cause deep burns if applied for some time - however this would be damage due to resitive heating; not due to the electricity itself.

The article on static electricity seems to indicate that a human can built up a static charge of 4000V to 35000V, which apart from a unpleasant jolt isn't harmful to us... because the amperage and duration is small. WegianWarrior (talk) 07:51, 24 May 2013 (UTC)[reply]

It takes a fairly high current density to cause permanent tissue damage, but the amount of current that flows through the tissue depends not only on the voltage, but also on skin resistance. Dry skin reduces the current, but sweating will increase it. At 450 volts there is a possibility that the skin resistance will be broken down (this alone would constitute tissue damage), allowing a much higher than expected current to flow. The main danger is that the shock current will interfere with the very small currents that control heartbeat. Even very tiny currents through the heart can cause fibrillation. I think the claim of no permanent tissue damage would have been a very risky one if the shocks had been real. No insurance company would have covered the experiment with real shocks! Dbfirs 14:55, 24 May 2013 (UTC)[reply]

Note there were really NO SHOCKS given to any "Learner" in the experiment. The dial marked "450 volts" etc was a prop, and the "Learner" was not really connected to the apparatus. In psychology experiments of the 1950's and 1960's the source in an actual aversive shock experiment might have been a source with high voltage and high internal resistance, so that the current was strictly limited to a low current which would not cause physical harm. The Milgram experiment gave the "Teacher" a sample shock from a 45 volt battery, given while the "shock generator" dial was set at 45 volts. The experimental writeup by Milgram does not refer to a current limiting resistor when the sample shock was given, but it would have been common practice at the time, and without it, a dangerous or fatal shock might have resulted, especially if the current had somehow passed through the heart of the victim. Without a limiting resistor, the current would have been limited by the slight internal resistance of the battery, the slight resistance of the wires, the resistance of the skin, and the body's internal resistance. Ref Desk has had previous discussions where it was claimed that a far smaller voltage could cause lethal shock if the skin resistance broke down. Edison (talk) 15:08, 24 May 2013 (UTC)[reply]

That writeup says the sample shocks were delivered to the wrist, presumably meaning both elecrodes were placed there, so chances of interfering with heart or brain would be nil. 45 volts is about what telephone lines run on, I believe, and I routinely rewire my phone lines with bare hands without feeling anything, so there must have been some sort of conducting gel or such used. (The voltage when the phone rings is quite a bit more, however, as I discovered the hard way once). Gzuckier (talk) 16:48, 24 May 2013 (UTC)[reply]

"The Milgram experiment used shocks up to 450 volts" - NO! That's not true. To be *completely* clear here - there were no actual shocks given to the "learner" in those experiments - it was all just a show to see how far the "teacher" would go, the "learner" was an actor, who was subjected to no shocks whatever. The statement that no permanent tissue damage would result was just a means to see how far someone would go in causing another person pain if an authority figure told them to...it didn't matter whether it was a true statement or not. SteveBaker (talk) 20:12, 24 May 2013 (UTC)[reply]

Did you read what I posted at 15:08 before posting your amazing new facts at 20:12? Edison (talk) 03:13, 25 May 2013 (UTC)[reply]

(... or what I assumed in the previous post at 14:55? ) I think real shocks could have been fairly safely performed with a limiting resistor of 50,000 ohms and both contacts on one wrist. The DC shock at 45 volts would have been very mild, whereas at 450 volts DC it would have been quite painful, but the limiting resistor would have prevented burns or breakdown of skin resistance, since the actual voltage across the skin would probably have remained under 100 volts. The amount of pain depends significantly on the type of contacts used. Don't try this at home, especially with AC voltages! The fairground game "pick up the coin" (from the bottom of a metal container of water whilst holding a spoon (connected to a pulsed DC circuit) in your other hand) used to be popular, even at school fairs, but health and safety would not allow it now. Dbfirs 09:13, 25 May 2013 (UTC)[reply]

It seems like excessive semantics to speak of a "450 volt" shock that only delivers under 100 volts thanks to an extra resistor in the way. Like saying you could wear rubber gloves and take the shock without harm at all. Wnt (talk) 17:53, 25 May 2013 (UTC)[reply]

Yes, but that's what happens with a limiting resistor. As stated right at the beginning of the replies, it's the current that determines the pain and the damage. Dbfirs 18:27, 25 May 2013 (UTC)[reply]

Scientific name for a local variety of radish (Choti) grown in Karnali region in Nepal

Choti (चोति) or Choto (चोतो) is a local name for a local variety of radish grown in high mountain areas (>2000 masl) in Karnali region in Nepal. Its photograph is included herewith. Would you please suggest (provide) me full scientific name for this variety of radish.

Best regards, Pramod Dahal, Mugu, Nepal — Preceding unsigned comment added by 49.244.70.123 (talk) 09:17, 24 May 2013 (UTC)[reply]

If it really is a radish, then like all radishes, it's scientific name is Raphanus sativus. Consider that the scientific name of Brassica oleracea covers several common vegetables, including cabbage and cauliflower, which if viewed on one's plate, would not appear to be that closely related, much less the exact same species. The same is probably true of various radish cultivars. --Jayron32 15:27, 24 May 2013 (UTC)[reply]

If it's a cultivated variety, then that's probably true. Just like the scientific name for a dog is Canis lupus familiaris - and we use that exact same scientific name for a Great Dane or a Chihuahua because they are of the same species - and it's possible that the same thing is going on here. It looks like there may be some varietal names out there that might apply: Raphanus sativus longipinnatus seems to be used to refer to the "Daikon" or "Mooli" white radish, which is commonly cultivated throughout East-Asia - but even that seems to come in a bunch of different variations - from globe-shaped to smooth roots to snake-like shapes. SteveBaker (talk)

Taxonomy of cultivated plants is particularly problematic. The Species problem, which is already a bit of a conundrum dealing with life forms whose breeding proceeds without human intervention, is a complete nightmare with cultivated plants, orders of magnitude moreso. I wish I could remember the place I read it (I think it may have been 1493: Uncovering the New World Columbus Created or a related book, but I can't locate it now), there's a real problem with the taxonomy of Potatos. There are many many hundreds of varieties of potatoes, and the entire group of them is basically like a multidimensional Ring species problem that taxonomists simply can't unravel. Some place all domesticated potatoes under a single species named Solanum tuberosum, however this paper here (which may have been the original paper behind the source above that I can't remember), notes "Past taxonomic treatments of wild and cultivated potato have differed tremendously among authors with regard to both the number of species recognized and the hypotheses of their interrelationships. In total, there are 494 epithets for wild and 626 epithets for cultivated taxa, including names not validly published. Recent classiﬁcations, however, recognize only about 100 wild species and four cultivated species." Scientists are still trying to unravel the potato problem; it's a total mess. At best, taxonomists try to assign a species based on whatever is believed to be the wild variety of the plant being cultivated today, but sometimes it isn't really clear how to do that, as the potato problem shoes, and that leads to all sorts of problems in giving scientific names to cultivated plants, and this includes our Radish above. --Jayron32 23:15, 24 May 2013 (UTC)[reply]

Breathing

I've heard that people are supposed to breath more with their diaphragm, so that when breathing in, your stomach is bulging and when breathing out it's supposed to flatten or get sucked in even. But sometimes I do it exactly on the contrary. Breathing in, stomach gets sucked in, breathing out, stomach bulges and it feels completely natural. Why is that? My explanation is this. It's less work for the body to do it the "wrong" way, but it results in more shallow breathing. What do you think? — Preceding unsigned comment added by 46.107.26.54 (talk) 12:52, 24 May 2013 (UTC)[reply]

In my Tai Chi class last night we practiced three different forms of 'breathing'. The one you are describing is referred to as 'reverse breathing'. It isn't wrong. For one thing it is the one used for breathing while exerting yourself. The most important thing about breathing is don't worry about it too much. RJFJR (talk) 19:52, 24 May 2013 (UTC)[reply]

In fact we have an article Reverse breathing. RJFJR (talk) 19:53, 24 May 2013 (UTC)[reply]

Smallest living being able to learn?

Which one? OsmanRF34 (talk) 19:04, 24 May 2013 (UTC)[reply]

There is quite a bit of evidence that single-celled protozoa can learn some simple responses. To get much smaller you would have to go to bacteria or archaea -- as far as I know there is no evidence that bacteria can learn in the sense of an individual cell modifying its behavior in response to a teaching signal. Looie496 (talk) 19:29, 24 May 2013 (UTC)[reply]

Yeah - amoeba have been shown[3] to be capable of simple learning. When temperatures drop, amoeba move more slowly. So they subjected amoeba to three regularly timed temperature drops - then left the temperature alone. When the fourth temperature change could be expected to happen, the amoeba slowed down unnecessarily - suggesting that they'd learned the temperature change interval and were actively predicting the next change.

But at this incredibly primitive level, it's tough to say what's "learning" and what's just a regular biological mechanism. My bet would be that these creatures have a biological clock that predicts temperature variations on a day/night cycle - and that there is a means for this cycle to be adjusted for different day lengths over the year. This experiment could easily provoke that mechanism into adjusting it's natural diurnal cycle to the time delay in the experimental setup. Technically, that's "learning" in that the creature changes it's future behavior based on past experience - but there are clearly inanimate objects that can do similar tricks.

SteveBaker (talk) 20:04, 24 May 2013 (UTC)[reply]

Really!? What inanimate object are you talking about? Dauto (talk) 13:52, 25 May 2013 (UTC)[reply]

My computer has learned to delete junk mail based on observing my reaction to getting it. My car's computer learns the driving style of it's owner and adapts it's fuel metering system accordingly. There are plenty of learning systems out there. SteveBaker (talk) 03:45, 26 May 2013 (UTC)[reply]

You are using the word metaphorically. Conscious organisms can learn totally unexpected associations. The devices you mention have been pre-programmed specifically to respond this way by intelligent programmers. μηδείς (talk) 03:59, 26 May 2013 (UTC)[reply]

I don't have a reference, but learning is usually considered to have an element of the arbitrary to it. In the case of protozoa reacting to changes in temperature with adaptations to the cold, the reaction is purely physiological and directly related as a natural response to the stimulus. But a dog learning and reacting to the command "shake" by lifting its paw and putting it in your hand has nothing to do with a physiological adaptation to the effects of the sound /ʃejk/. The connection between that sound and that act is entirely arbitrary, and hence described as learned. μηδείς (talk) 02:26, 25 May 2013 (UTC)[reply]

If a child touches something hot or sharp or whatever, and gets hurt by it, and thus stops touching those kinds of things, is that physiological? Or is it learning? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:14, 25 May 2013 (UTC)[reply]

It would be learning because there's no direct causal link between being burnt and not touching things that look like stoves--it's a psychological association mediated by pain. A purely physiological response would be blistering or scarring. (Obviously everything biological is alos physiological at some level--don't get hung up on that.) μηδείς (talk) 17:00, 25 May 2013 (UTC)[reply]

Or perhaps life is by definition the ability to learn (i.e. the ability of the system to process information and adapt itself accordingly). Count Iblis (talk) 17:34, 25 May 2013 (UTC)[reply]

We invent these words and then try to decide whether living things have them or not. It is alleged that a virus is not a living thing. It's apparent that the virus couldn't care less whether we consider it alive or not - it continues to do what it does. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:52, 25 May 2013 (UTC)[reply]

I agree, and would say that concepts are tools that we design to deal with nature; they do not constrain nature. And our tools can be well or less well-designed. Some tools are objectively better than others. μηδείς (talk) 03:01, 26 May 2013 (UTC)[reply]

That's called adaptation. If we want to speak metaphorically, that's fine. But adaptation and learning are perfectly good distinct concepts, and if we say that all adaptation is learning the distinction is lost, and we might as well say there is no such thing as learning, only adaptation. μηδείς (talk) 17:48, 25 May 2013 (UTC)[reply]

The octopus supposedly displays problem-solving intelligence. Does that mean it's hard-wired, or do they learn from experience? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:49, 25 May 2013 (UTC)[reply]

I am not the person to ask about octopuses, but basically nervous systems and brains act by connecting sensory inputs with motor outputs and providing ever more sophisticated feedback in higher animals. When the feedback is acquired and when there is no direct physiological association between the input and the output it is called learning. An exact definition of learning will depend on the context. What are are called hard-wired behaviors or instincts are better defined as fixed action patterns, such as the unlearned but seemingly intelligent behaviors of wasps that build nests for their young and sting and drag in prey without ever having witnessed another wasp do the same thing. That is definitely not learning, while trial and error is, as is learning by example and explicit instruction. I have seen videos of octopuses doing things like unscrewing jars to remove prey, which seems to be trial and error action. If they get better at it over time it would be learning. μηδείς (talk) 20:58, 25 May 2013 (UTC)[reply]

So if I'm reading you correctly, that could be called "learning from experience", i.e. figuring out how to do something via trial and error, and then retaining that knowledge when next faced with a similar problem. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:15, 26 May 2013 (UTC)[reply]

I am trying desperately not to argue in favor of any point since it's synthesis and OR. But if I were to use the phrase learning by experience I would contrast it with instinct on one side (which is not learning) and learning by instruction on the other, which is being told something, rather than figuring it out. Given learning requires memory I would strongly recommend the book On Intelligence] by Jeff Hawknis. μηδείς (talk) 02:59, 26 May 2013 (UTC)[reply]

Can you gain more weight than you eat?

A friend of mine who's on a diet, today grabbed a pint (16oz) of Ben & Jerry's double chocolate ice cream. When I mentioned the weight gain, she said "I can afford to gain a pound", because that is the weight of the ice cream. This got me wondering, is it possible to eat something and gain more weight than the weight of the food? — Preceding unsigned comment added by 71.62.100.91 (talk) 20:49, 24 May 2013 (UTC)[reply]

There are some foods, like olive oil, that are more calorie rich than human fat. In theory eating thse will cause you to gain more weight than the food itself weighs, the balance comes from water during metabolism--Digrpat (talk) 21:24, 24 May 2013 (UTC)[reply]

Energy and thus mass are conserved. If you ingest one gram of matter, you cannot gain two grams of mass. However, theoretically it could be possible to eat one gram of a substance that somehow grabs another gram of your breathing air and binds it to your body. Practically, I highly doubt that happens in practice. Real foods contain things like water, which are expelled from your body, far outweighing any air-binding properties of the remainder of food molecules. 88.112.41.6 (talk) 21:27, 24 May 2013 (UTC)[reply]

I had a similar answer but was edit-conflicted. No, your gain in weight is exactly what you ingest (including the air you breathe in) minus what you excrete (and breathe out). So, unless eating all that ice cream makes you excrete less (or become more soporific and breathe out less carbon dioxide), you will not gain more than a pound. Is that any comfort? The point Digrpat is making is relevant if eating one food makes you eat (or, in the case given, drink) more of another. Thincat (talk) 21:50, 24 May 2013 (UTC)[reply]

Dieters talk of "water weight." If you eat some mass of salt, it could supposedly cause your body to retain water of greater mass than the salt. Naturally, you would also have to drink fluids containing water for this to occur. Edison (talk) 03:08, 25 May 2013 (UTC)[reply]

It's also possible that you could eat one food item that would facilitate the absorption of nutrients from other food items that would have otherwise not absorbed by the body. Think of it as a catalyser. that would make you gain more weight that the food item itself. Dauto (talk) 13:58, 25 May 2013 (UTC)[reply]

I don't see how. If you eat a pound of something, at that moment you have gained a pound, no more, no less. The process you describe could cause you to retain that extra weight - but you can't get something from nothing. Your body has a certain total mass. No matter how the molecules recombine at some given moment, your mass is going to stay the same at that moment, right? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:10, 25 May 2013 (UTC)[reply]

True, but as the comments above suggest, theoretically it is possible to gain a certain amount of mass from the air. For example, we metabolize fat by oxidizing it. Fat is almost entirely composed of carbon and hydrogen, and oxygen atoms are heavier than either of those, so when a fat molecule is oxidized, its mass (or rather, the net mass of the products) increases significantly. I can't imagine a scenario where that gain in mass would actually be measurable at the whole-body level, though. Looie496 (talk) 15:24, 25 May 2013 (UTC)[reply]

You're still ingesting it, though. You weigh more after inhaling than after exhaling, for example. You can absorb things through the skin also. If the question is confined to strictly eating in the usual way, then it could be possible, though it won't happen immediately. It still has to add up to + ingest and - excrete, one way or another. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:31, 25 May 2013 (UTC)[reply]

Hey bugs, nobody is claiming that mass is not conserved - duh. What we're claiming is that an item might make you gain weight from other sources. Weight that you might otherwise have not gained. Dauto (talk) 17:03, 25 May 2013 (UTC)[reply]

The OPs question was about weight, not mass. I'm a bit disappointed that no one grammarnazied on the difference yet. 93.132.188.84 (talk) 17:30, 25 May 2013 (UTC)[reply]

Unless someone is planning a trip to the moon, the distinction is moot. --Jayron32 19:06, 25 May 2013 (UTC)[reply]

Quite as moot as any mentioning of mass energy conservation. We lose mass not only by breathing but also by urinating, defecating and sweating. The OPs question cannot be interpreted simply by taking only the intake mass in account but by shifting the balance between intake and general excretion. If someone measures his weight(loss) after doing sports and before replenishing the water loss by drinking some water, that's cheating. If some lank hyperactive person takes some milligrams of some drug that makes him more calm this may shift the balance quite more then the weight of the pill. — Preceding unsigned comment added by 93.132.188.84 (talk) 19:32, 25 May 2013 (UTC)[reply]

The question is, are we defining drinking as eating? Digrpat answered this question correctly above. μηδείς (talk) 17:51, 25 May 2013 (UTC)[reply]

For that matter, how about defining inhaling as "eating"? The questioner asks if it's possible to eat a pound of something and gain more than a pound. If you're only taking the eaten item into account, apparently it's possible. But that's also misleading, as it's denying part of the ingest-minus-excrete equation. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:47, 25 May 2013 (UTC)[reply]

No, inhaling would not be relevant, because the six 02 molecules consumed in the respirative consumption of one sugar molecule are balanced by six exhaled CO2 molecules. μηδείς (talk) 21:09, 25 May 2013 (UTC) Some of the sugar is also converted to water, but the water is produced from the already consumed sugar. (That is, one could potentially gain weight by the reuse of water from sugar respiration being used in later fat metabolism, but that water would be subtracted from the balance of the mass of the already present sugar. We do not metabolize inhaled hydrogen as such.) μηδείς (talk) 21:09, 25 May 2013 (UTC)[reply]

You seem to have missed the bit about the fat metabolism rather than sugar. Roughly CH₂ + 3/2 O₂ → H₂O +CO₂. Molecular weight 14 changes to 18 in the body even counting the loss of carbon dioxide. Perhaps there are other ways to gain weight, absorb water or cosmetics via the skin, dirt and dust in the lung, lead in the form of bullets, lowering air pressure to reduce buoyancy. I don't think these last would be noticeable on the scales though! Graeme Bartlett (talk) 23:08, 25 May 2013 (UTC)[reply]

I assume you are addressing me, Graeme, but I am not sure, and if so I am not quite sure of your point. Are you suggesting that the water from metabolized fat is retained as body weight? μηδείς (talk) 02:53, 26 May 2013 (UTC)[reply]

We've strayed a bit from the original question here. There is a great book on dieting called The Hacker's Diet which goes into all of the science of this.

There is a wonderfully informative image there: http://www.fourmilab.ch/hackdiet/e4/figures/figure355.png - which is claimed to come from a NASA study. Basically, what goes into a well-balanced person's body each day is:

2.5 lbs of food,
9.2 lbs of water,
1.8 lbs of oxygen.

What comes out is:

0.3 lbs of solids (basically, poop),
11 lbs of water (pee, sweat and moisture in your breath),
2.2 lbs of CO2.

So 13.5 lbs go in and 13.5 lbs go out again - and by simple conservation laws, you don't gain weight when averaged over the course of the day. But obviously, if you drink a pound of water - then your weight goes up by 1 lb until you pee 1 lb of it back out again...so this can only ever be an average. Your weight bounces up and down again by 5 to 10 lbs throughout the day. That 1 lb of ice-cream is hard to track through all of that - but if you ate an extra 1 lb of the stuff every single day, the results would be a steady weight gain.

It's instructive to note that more water goes out than comes in. Humans make close to 2 lbs of water a day!

Since you really can't not drink when you're thirsty - if you eat some food that requires more water to metabolize it than most other foods do (eg because it contains a lot of salt) or some food that produces less excess water as you digest it - then the amount of pee might drop below 11 lbs and/or the amount of water you find yourself needing to drink to avoid getting too thirsty might increase above 9.2 lbs - and it's fair to say that because you ate that thing you gained more weight than the thing itself weighed.

In fact, since we're talking averages here - unless all foods produce exactly the same amounts of excess water and solids - it would be surprising if some were not above the average and others below...so in some sense, eating a pound of one of the below average ones would indeed cause you to gain more than a pound...just because others cause you to lose less and some balance has to be maintained.

That said - if you weigh yourself immediately before eating the ice cream and immediately afterwards, your weight gain would be exactly 1lb. That's true for 1 lb of lettuce and for 1 lb of pure salt...but if you follow normal behavior afterwards, it's possible for you to gain either more or less than 1 lb over the following hours as a result of eating it.

Now, we can argue silly semantic or philosophical points about whether the weight gain was "caused" by eating the food or because you subsequently felt the need to drink more or because you failed to pee as much...but what our OP is asking is fairly answered as "Yes, it's theoretically possible that eating 1 lb of ice cream would directly or indirectly cause your long-term average weight to go up by more than 1 lb over the following day or so.".

But the question I'd offer your friend is this:

"If you hadn't eaten that pound of ice cream - would you have eaten a pound of something else instead?"

...that's a critical part of this! I'd guess that after eating 1 lb of ice cream, you'd be less inclined to eat as much in the next meal - in which case your weight gain is highly likely to be much less than 1 lb.

SteveBaker (talk) 03:31, 26 May 2013 (UTC)[reply]

I am so glad you finally cut through everybody else's silliness, Steve. Unfortunately talking about "food" and averages instead of specific fats or carbs throws the baby out with the bathwater. μηδείς (talk) 04:04, 26 May 2013 (UTC)[reply]

May 25

Are super-tankers fully automated ?

Hi Everyone.
In Superman III and Hackers (and many other fictions, I guess), it is said that modern oil tankers can not be controlled manualy and are totaly driven by computers. I wonder if this is accurate. I know that in the 1970s there have been numerous tankers hijacking stories and I guess automation is a way to avoid that ? If there is a super-tanker captain here, I'd be glad to here what he says about that ;-) Jean-no (talk) 13:43, 25 May 2013 (UTC)[reply]

If by fully automated you mean so automated that computers set the course in a way that humans can't override, certainly not. That would be insane. See Exxon Valdez oil spill, among other things. Looie496 (talk) 14:40, 25 May 2013 (UTC)[reply]

According to the article on that spill, the main causes were human fatigue and failure to maintain equipment. It seems like full automation may have mitigated or even prevented it. 202.155.85.18 (talk) 02:18, 27 May 2013 (UTC)[reply]

In the movies I mention, the ship's course is decided by distant and centralized computers. It seems quite dangerous to me, so I guess the writers didn't understand well something... Jean-no (talk) 15:01, 25 May 2013 (UTC)[reply]

I suppose by automated they could mean computerized, such that the controls could be hijacked. So not like the captain and crew does nothing, but more like Fly-by-wire for boats. Mingmingla (talk) 15:22, 25 May 2013 (UTC)[reply]

There are (at least) two separate questions there. The first is whether or not such functions are computerized/automated, the second is whether or not the computer is required to carry out those functions: adjusting ballast, controlling the engine and rudder settings. (The third implicit question, I suppose, is whether or not those functions are, or can be, remotely controlled. My common-sense response is "Why the hell would you put that on the internet?", though dumber things have happened. Absent any evidence to the contrary, I would be very reluctant to presume that the capability exists; there probably isn't an idiot oil-industry exec who has said "Please, can I adjust ballast on a supertanker from my iPhone?") TenOfAllTrades(talk) 16:40, 25 May 2013 (UTC)[reply]

My unschooled thought is that more security would be needed than you'd think. At some point the computer now on board the tanker could have been connected to the Internet, and somebody might have had a pop-up "Would you like to update your map of the reef to include the most recent soundings?" and not realized that someone was spoofing the update site and uploading a map that shows clear water sailing straight through Diamond Head. The ship probably has an autopilot, which could remain engaged if the crew had ... an accident. Indeed, the 'accident' might well have been loaded on board together with the new navigation computer. I suspect the movies were more dramatic than this, though! Wnt (talk) 17:47, 25 May 2013 (UTC)[reply]

Movie plot threats aside, do you actually know anything about how navigational or control systems on board a supertanker work? TenOfAllTrades(talk) 22:39, 25 May 2013 (UTC)[reply]

I didn't know the expression "Movie plot threat", I love it. Jean-no (talk) 22:53, 25 May 2013 (UTC)[reply]

The real movie plot threat is the Terminator 2: Judgement Day! The singularity is near!Shadowjams (talk) 00:53, 26 May 2013 (UTC)[reply]

To be clear - no. I just wanted to keep people's minds open about the idea in theory, as SteveBaker has done at more length below. Wnt (talk) 18:44, 26 May 2013 (UTC)[reply]

Several approaches exist to infecting and controlling computers that are not, nor have ever been connected to any networks whatever. You can even devise attacks for computers that are physically incapable of being connected to any outside communications whatever!

This seems unlikely - but it's actually happened. The most famous is the Stuxnet system which was an effort (allegedly by the US and/or Israel) to disrupt uranium enrichment plants in Iran that were controlled only by very simple microcontroller chips with no network capability whatever.

It worked by first infecting computers that WERE connected to the Internet, then having those machines place malware on things like thumb-drives, cellphones and MP3 players that were plugged into those machines - then when someone who designed automation software for Iran charged their infected phone or MP3 player by plugging it into their (network-isolated) software design workstation, the infection was spread into the software that was used to program the dedicated microcontrollers - which in turn caused covert software to be placed into their firmware that caused them to fail under some future circumstances and to hide that failure from instrumentation designed to see faults exactly like that!

That approach requires massive amounts of patience and investment in time and money to get all of those steps to work correctly - but the outcome in that case is well known to have been moderately successful.

It seems entirely reasonable to me that a similar trick - planned years in advance by some kind of James Bond super-villian - could allow one to give a super-tanker some predefined commands that would be hard for the crew to diagnose or rectify without knowing what was happening and why.

That said, the emphasis would be on "predefined". It would likely be impossible for any degree of control over the tanker to be had remotely during such an event. But a sufficiently cunning bad guy could certainly have the thing subtly veer off course and crash into something important unless the captain enters some special code-word into the computer via whatever controls he has. A system like Stuxnet is capable of doing just that. Now, obviously if it took control of the tanker hours before this impact, the crew could disconnect the computers and shut down the engines by cutting power lines with an axe or something - but if it jammed the bow thrusters into full power right in the middle of threading a course through some narrow gap between two rocky outcrops in the middle of the night - and the radar and other navigation computers were rigged to make it look like the correct course were being followed - it could probably cause the needed mayhem before the crew could figure out what was happening.

The plot of that Bond movie where the British warship is sent off-course into Chinese waters by doing something nasty to its GPS is exactly the kind of thing that a Stuxnet type of system could use to have a supertanker run aground and cause an ecological and political nightmare someplace.

Basically, it *is* technologically plausible...but unlikely.

SteveBaker (talk) 02:56, 26 May 2013 (UTC)[reply]

Again I ask, does anyone know anything specific about the degree of automation or computerization of the controls of a supertanker or large freighter? Is there actually a USB port on the bridge where a crewmember can plug in his mp3 player and run arbitrary, malicious Windows code on the navigational and control systems simultaneously? I can't speak to the plausibility of Steve's scenario, because – correct me if I am mistaken – no one here has actually done any research into the questions asked, nor admitted to so much as working aboard a ship, let alone ever reflashing a supertanker's firmware. TenOfAllTrades(talk) 19:14, 26 May 2013 (UTC)[reply]

Well, it's something of a hypothetical question -- pirate attacks do occur, but they actually do encounter a crew. (in one case, 25) Of course, the way pirate attacks usually go, the crew ends up being a liability as hostages, not really a guarantee nothing bad is going to happen. Wnt (talk) 21:13, 26 May 2013 (UTC)[reply]

For an interesting parallel, see [4]. That's about airplanes, but the point is, apparently in the corporate world nobody really cares what could happen, as long as they can get through tomorrow. Wnt (talk) 03:56, 27 May 2013 (UTC)[reply]

I just love it when folk include links to articles as though the articles support the nonsense they claim. In this case there is a slight twist: The news item cited by Wnt does state that someone claimed you can misdirect an aircraft with a phone. But there is a link at the bottom of it to another news item issued a couple of days later. It quotes an official American FAA press release and the relevant systems manufacturer - both state that its a load of codswallop - you simply cannot take over a plane with an andriod phone - and some technical detail why is given. Wickwack 120.145.154.162 (talk) 10:59, 27 May 2013 (UTC)[reply]

Solubility of Iron(II) oxalate

Iron(II) oxalate says it is slightly soluble, but Oxalate#Physiological effects says highly insoluble. Which is correct? — Preceding unsigned comment added by 93.132.188.84 (talk) 15:47, 25 May 2013 (UTC)[reply]

It's plausible that both are correct, insofar as they are subjective, context-specific descriptions. Iron oxalate obviously has a specific solubility constant in water; but it's not available in NIST's online database. The next step would be to check a handbook of chemistry and physics constants (e.g., the CRC Handbook of Chemistry and Physics); maybe one of our chemistry-minded regulars has a copy of such a resource handy. Nimur (talk) 16:23, 25 May 2013 (UTC)[reply]

Here it is at PubChem: FERROUS OXALATE, again only with subjective description of the solubility. Nimur (talk) 16:33, 25 May 2013 (UTC)[reply]

It's a bit of a shock if both should be correct in the respective (and highly unspecified) contexts. 93.132.188.84 (talk) 16:52, 25 May 2013 (UTC)[reply]

What's the difference between slightly sober and highly drunk? Seriously, words like "slightly" and "very" are quite imprecise, and there's nothing that makes "slightly soluble" and "highly insoluble" incompatible. If your really want to know, you need the K_sp value for Iron (II) oxalate. This says the K_sp value is 2 x 10^-7. Since this is a 1:1 ionic compound, that means that the molar solubility is SQRT (K_sp), which would be 2 x 10^-7/2 = 6 x 10^-4 mol/L. --Jayron32 18:39, 25 May 2013 (UTC)[reply]

So wouldn't it be better to avoid those imprecise (weasel-) words in those articles? At least in those fact-boxes for chemical substances? 93.132.188.84 (talk) 18:52, 25 May 2013 (UTC)[reply]

I'm neither here nor there on that. Many sources use terms like "slightly soluble". But if you wanted to add a bit to directly list the Ksp, and link to the reference I gave, additional information is always good. --Jayron32 19:04, 25 May 2013 (UTC)[reply]

Last few times I tried to edit anything on wikipedia failed due to one restriction or the other. I'd rather leave that to the "insiders". 93.132.188.84 (talk) 19:19, 25 May 2013 (UTC)[reply]

This reminds me of the question I asked earlier. The answer seems to be that as adjectives, 'very', 'highly', 'slightly', and the words 'soluble' and 'insoluble' are highly subjective terms. Other subjective words that also pop up frequently in science, include 'inorganic' and 'warm/hot' and 'metalloid'. Plasmic Physics (talk) 09:00, 27 May 2013 (UTC)[reply]

Universal constants are very important to effective scientific communication, but it seems that these words have escaped attention. Even arbitrarily bounded definitions would prevent such confusion. For now, they remain the bain of science, subject to the various schools of thought, and the rogue individual. Plasmic Physics (talk) 09:06, 27 May 2013 (UTC)[reply]

Organ theft

Has there ever been a confirmed case where someone has been convicted of kidnapping people and stealing, then selling their organs on the black market? I've had a look around the web, and I see that people have occasionally been *accused* of it, but then the true story turns out to be something less sensational when it goes to trial.

I'm not talking about the urban legends of serial killers being paid by the Russian mafia/Triads/etc. to abduct hobos and teenage runaways from the streets of Western cities and 'harvest' their organs for sale to rich people in the far east either. I've heard that stuff before and I'm pretty sure that it is 100% 'hooey'. Or travellers who get their drinks spiked and wake up in motel room bathtubs having had their kidneys stolen. --87.112.25.55 (talk) 22:30, 25 May 2013 (UTC)[reply]

Organ theft in Kosovo. TenOfAllTrades(talk) 22:32, 25 May 2013 (UTC)[reply]

May 26

Antipsychotic studies

in the text of this study http://www.sciencedirect.com/science/article/pii/S0006322310011716 it states "Fourth, our experimental design does not address whether the APD-induced morphological changes are reversible, a question of significant theoretical and practical relevance. Drug withdrawal studies to address this possibility are currently underway." That was in 2011. have these drug withdrawal studies been completed and published since then? — Preceding unsigned comment added by 63.247.60.254 (talk) 19:23, 26 May 2013 (UTC)[reply]

I just typed the last author's name into PubMed and got back a likely looking result: [5] (By convention, the last name on biological science papers is usually the person running the lab). If you want to dive deeper than that, you really can use the little envelope link next to Shitij Kapur's name and ask him directly, though it may be useful to make a few more PubMed searches first to get some background. Wnt (talk) 21:24, 26 May 2013 (UTC)[reply]

Sky cloudier near ocean

Does the sky near the ocean have more clouds than more inland, on the average? Bubba73 ^{You talkin' to me?} 21:52, 26 May 2013 (UTC)[reply]

I assume one realizes there are hundreds of thousands of miles of coastline? Condensation will occur when warm humid air blows into cool areas, such as that above land in the Fall when the water is still retaining the Summer's heat in relation to the land. But the question as stated is too vague for a yes/no response. μηδείς (talk) 22:48, 26 May 2013 (UTC)[reply]

This site has 25 years of global averaged cloud cover. Between that and the image at our cloud cover article (an average of October 2009), I observe that, broadly, cloud cover over the ocean tends to be at least as heavy as cloud cover shortly inland from that location. This does not hold everywhere, but is at least a rough trend. Note particularly how much of the coastline in the Oct 2009 image on Wikipedia is dark and sharply defined, indicating relatively low cloud cover. On the other hand, the majority of the North American and European coasts are hard to distinguish -- there's not much of that trend in those locations. In the area of Kenya, it even appears to be the opposite -- the coastline is apparent, but the sea is darker. — Lomn 22:52, 26 May 2013 (UTC)[reply]

Resolved

Thank you. It is not quite like I imagined it might be. Bubba73 ^{You talkin' to me?} 02:06, 27 May 2013 (UTC)[reply]

May 27

Salt and sea salt

There's a lot of advertising and hype about sea salt which, for reasons that remain mysterious to me, is better for you than other salt. I expected that this was a recent craze, but I was watching a not-so-recent film La Regle de Jeu where one of the characters is on a "diet" that she can't have salt but can have sea salt. The chef dismisses it as nonsense, subtitled as "She can eat like everybody else. Diets I can accept, but not obsessions." How far back does this go as a health craze? 71.231.186.92 (talk) 00:20, 27 May 2013 (UTC)[reply]

Sea salt contains a little bit of alternative ions to sodium, but it generally doesn't contain enough to really reduce the dose enough to help tremendously with sodium reduction (by comparison to pure or half-potassium formulations on the market). Editorial: I wish I could find good balanced salts for human consumption at supermarkets with better levels of potassium/magnesium/calcium/etc. In terms of nutrition, sea salt is a poor substitute for the more balanced land salt that our ancestors were accustomed to, and which is still favored in some traditional cultures. The notion everybody learns that "table salt" is "sodium chloride" is one of the more dangerous myths in modern culture. Wnt (talk) 01:06, 27 May 2013 (UTC)[reply]

Wnt, as you are aware, you can buy the readily available "Lite Salt", which is 50:50 sodium salt and potassium salt, marketed to people who want to reduce sodium intake. However, people usually increase the amount they use as it lacks taste. So you end up with just about as much sodium, and a lot more potassium, which can cause medical issues of its' own. You should be getting calcium from milk. Wickwack 120.145.190.145 (talk) 02:24, 27 May 2013 (UTC) [reply]

That's surprising to hear, because in my personal experience it isn't true; if I'm hungry for potassium then I have a hunger for salt but it doesn't fill the need, so I use more and more. Definitely I prefer the flavor of the salt with some potassium in it to the slightly sour taste of pure sodium salt, especially when I'm hungry for it. But I think "Lite Salt" can be formulated with at least a little and maybe a lot of magnesium and calcium with what I think could be an actual improvement in flavor for at least some applications. (I've seen some foods like chick peas actually packed in calcium salt solution) Wnt (talk) 04:02, 27 May 2013 (UTC)[reply]

Sea salt is not iodized. Some people think they're getting too much iodine, and those people are usually the types that carry on about eating "natural", so sea salt appeals to them. 202.155.85.18 (talk) 01:50, 27 May 2013 (UTC)[reply]

As far as a craze is concerned, it may depend on which country you live in. In Australia, by law, salt packaged for consumers is iodized (salts of iodine added) as it was found that thyriod problems due to iodine deficiency occurred in susceptable people. Australian salt has for decades been sold in very plain packaging, and it has always been sea salt, produced by evaporating sea water in large pans, by Dampier Salt and other companies. It was never labelled as "sea salt" - just "salt" or "table salt". However, in the last few years, shops have been stocking imported sea salt and it (mostly) is not iodised - it gets around the law as it is not packaged in Australia. It is also sold in modern attractive packaging and labelled as "sea salt". The craze is thus driven by three coincident things: a) it avoids the problem of many people who are distrustfull of "population medication" (same as the dubious objection to folate in bread, flouride in water, etc); b) more attractive modern packaging; and c) a hazy notion that as it is different and new, it must be better. For decades, thyroid disease has been very rare, but now to a minor extent it has come back. There is no scientific benefit in the imported sea salt - in fact you are better off with the local iodized salt. However I notice that recently the main Australian retail company has risen to the occaison by marketing "iodized sea salt" (actually exactly what they have always sold) in nice packaging, at a premium price. Wickwack 120.145.190.145 (talk) 02:10, 27 May 2013 (UTC)[reply]

Do you have a ref for the Australian law banning the packaging of non-iodized salt? I'm having trouble finding any other source that says that. 202.155.85.18 (talk) 03:14, 27 May 2013 (UTC)[reply]

There's no law banning the packaging of non-iodized salt - rather there is a mandatory food standard requiring that salt packaged for retail/domestic use be iodised, and bread for sale be made with iodized salt. Ref Mandatory Iodine Fortification, Food Standards Australia. Wickwack 124.178.154.108 (talk) 04:04, 27 May 2013 (UTC)[reply]

Does anybody actually have an answer for the OP: when this fad started? Clarityfiend (talk) 09:32, 27 May 2013 (UTC)[reply]

this link suggests that it has been within the last 15 years or so. Since the UK and France tend to be where these things started (Maldon, Fleur de Sel), I would be willing to take that at face value. -- [ UseTheCommandLine ~/talk ] # _ 10:27, 27 May 2013 (UTC)[reply]

And as I said in my first post, in Australia at least, within the last few years. Of course the OP is probably not in Australia, but I expect other Western countries to be similar - they usually are. Wickwack 120.145.154.162 (talk) 11:05, 27 May 2013 (UTC)[reply]

ELectrostatic Energy

What do you know by electrostatic energy of discrete and continous distribution of charges? — Preceding unsigned comment added by Titunsam (talk • contribs) 12:42, 27 May 2013 (UTC)[reply]

Oh, heaps and heaps. What do you want to know?