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April 2

questions about asteroids and dwarf planets

Is there a website that has questions that have been asked before about asteroids and dwarf planets? Donmust90 (talk) 15:00, 2 April 2017 (UTC)Donmust90Donmust90 (talk) 15:00, 2 April 2017 (UTC)

You can start here[1] --AboutFace 22 (talk) 16:04, 2 April 2017 (UTC)

Is there any organ in the body that's normally not grow after the birth?

Is there any organ in the body that's normally not grow after the birth? When I think about the brain, skull, and the rest of the organs as well I find that they get growing with the age after the birth. then my question is if there's any organ in the body that's normally not grow after the birth? (For now if I'm not mistaken I know about thymus gland for example that with the age it is going and reduced) 93.126.88.30 (talk) 16:53, 2 April 2017 (UTC)

You'll have to define what you mean with grow. Get bigger of form new cells? For instance, it was long thought that the brain was born with all cells in place, and growth was due individual cells forming more connections. We now know that's not true (adult neurogenesis). The only thing I can think of right now that might be an answer to your question is the human oocyte population, it's normally assumed that women are born with all their eggs, and no are formed in the adult. However, as out article (oogenesis) suggests, this might not be true either. Fgf10 (talk) 17:42, 2 April 2017 (UTC)

Googling human body part does not grow suggests the ossicles, with corneas being a "maybe". 91.155.195.247 (talk) 17:47, 2 April 2017 (UTC)

Eyeballs stop growing rather early. It's not birth though. Sagittarian Milky Way (talk) 20:12, 2 April 2017 (UTC)

Some organs shrink and become residual, and some others disappear. Eg placenta, yolk sac, Pharyngeal arches, Buccopharyngeal membrane, Chorion, Vitelline duct, umbilical cord, Ductus arteriosus, Foramen ovale (heart), Ductus venosus. Graeme Bartlett (talk) 15:17, 3 April 2017 (UTC)

How about the thymus[2] --AboutFace 22 (talk) 20:42, 3 April 2017 (UTC)

Is it better / worse to transplant seed without its coat?

If I want to transplant mango by putting its seed in the ground, then does it matter weather I'll put it together with its coat or not? will it grow faster if I'll take out the coat of the seed or maybe it will interrupt it to grow or it doesn't matter? 93.126.88.30 (talk) 17:00, 2 April 2017 (UTC)

See http://www.wikihow.com/Plant-a-Mango-Seed Richerman (talk) 18:58, 2 April 2017 (UTC)

The "good pain"

What is the physiological or neurological basis for the qualitatively different sensation of pain that feels "good" during a massage, as opposed to the kind of pain that is unpleasant? 66.66.228.95 (talk) 20:46, 2 April 2017 (UTC)

Massage releases endorphins that change the perception of pain and give a sense of euphoria [3][4] Richerman (talk) 23:05, 2 April 2017 (UTC)

It may help to read Gate control theory. DrChrissy ^(talk) 23:29, 2 April 2017 (UTC)

Massages don't seem to work for me. They hurt! I hate it when I'm offered a massage! 50.4.236.254 (talk) 23:40, 2 April 2017 (UTC)

You can always say "no, thank you." There is a whole range of massage, from gentle relaxing rubdowns to intense deep tissue work that's guaranteed to hurt like hell at times. --jpgordon^{𝄢𝄆 𝄐𝄇} 04:05, 3 April 2017 (UTC)

This is a question that directly exposes the lack of understanding we have with regard to this fascinating variety of qualia. We can, to some extent, isolate the neurophysiological correlates that associate with "good" or "bad" pain (as self-defined by someone experiencing it while taking part in a brain imaging study or other experiment, for example). Richerman correctly identifies endorphins as a big player in this distinction, but they collectively represent just one factor in an indescribably complex set of mechanisms which are recruited for this kind of perception/sensation. But its even more complicated than that, because this question touches upon the hard problem of consciousness and of subjective experience.

Further, we have a lot of evidence that psychological state can have a profound impact on how a person perceives the exact same stimuli, further reinforcing that how a particular percept is processed within the flow of conscious experience is not strictly defined by the stimuli itself, nor solely by the more "external" components of the physiological processes which give rise to the raw sensory data. It varies greatly by individual per context and, as we all know, significantly between individuals. And the difficulty in parsing the borders between co-occuring sensations is profound; one person who gets a deep tissue massage may describe it as pain followed by pleasure, where another may just regard it as thoroughly pleasant experience and a third as horrifically painful, through and through. Who is correctly reporting the sensation, even when they overlap in rating the experience as generally pleasurable (or painful)? Does the question even make sense in evaluating subjective conscious sensory experience? How much is the difference due to our lack of an inter-common and accurate empirical metric by which to express the sensation via natural language, and how much is it due to a genuinely different sensation? We have no such thing as first principles when it comes to the understanding of perception at this level.

I gather you were probably looking for more of a straightforward biopsychological explanation rather than a dip into metaphysics and ontology. And indeed, there are neurological correlates; if you studied the brain of a person reporting "good" and "bad" pain, you'd not only see different activity in terms of transmitters released, but different levels of heightened activity in different brain regions associated with nociception, the somatic senses generally, alertness regulation, and so forth. But that really is just the start of the inquiry. Snow ^{let's rap} 21:05, 3 April 2017 (UTC)

This also reminds me of the instinctive need to chew as growing teeth emerge. It is slightly painful but addictive. Which is not so different than the urge to scratch when intense itching is felt, which can cause injury in some cases. Another interesting factor is the threshold of pain which varies with individual, age and circumstances. Some tests have also shown that the density of sensitive nerves varies, i.e. using needles and measuring the distance between points (I forgot the name of this test). Of course, some also like to experience certain levels of pain, and the previously mentioned endorphins also play a role. Hot spices, and for some, BDSM activities... —╰]PaleoNeonate█ ⏎ ?ERROR╮ 02:23, 6 April 2017 (UTC)

How are other galaxies receding from us

Are other galaxies themselves receding from us,or is space moving them away from us?Uncle dan is home (talk) 23:19, 2 April 2017 (UTC)

Yes. 50.4.236.254 (talk) 23:57, 2 April 2017 (UTC)

I agree with 254. On average, other galaxies are moving away from us, and the farther away the galaxies are, the faster they are moving away. See Hubble's law and Hubble flow. There is a degree of variation, so not every galaxy at the same distance moves at the exact same speed. (The differences are referred to as peculiar motions.) For galaxies that are very close to us, some of the peculiar motions will actually mean that a few are getting closer to us rather than farther apart. But returning to the crux of the question is A) the space between galaxies expanding, or B) the galaxies receding simply because their current velocities carry them away from us? For distances up to a substantial fraction of the size of the visible universe, the answer is "yes". Either description A) or B) gives you the same dynamics and describes the universe we observe equally well. One can either postulate that the space between galaxies is expanding, or one can postulate the galaxies are moving away because their initial velocities are such that they must move away. The apparent "metric expansion of space" is equivalent to the simple inertial motion of galaxies that were at some point in the past (i.e. the Big Bang) imparted with a initial velocity distribution that causes them to fly apart. Until one gets to very large scales or early times (i.e. requiring general relativity and/or dark energy), the past and future of the Hubble flow can be accurately modeled using simple Newtonian mechanics, assuming only Newtonian gravity and a rather peculiar distribution of current velocities that increases with current distance. Of course, general relativity is a better understanding of gravity and the universe than Newton had, and in the relativistic point of view we can form a more complete picture of the evolution (i.e. including large distance and early times). People who emphasize the understanding of general relativity tend to describe space as expanding. That is also a reasonable way to look at things, though for my money it is equally fair to say that the galaxies are receding because they have a distribution of velocities that causes them to recede. Dragons flight (talk) 16:34, 3 April 2017 (UTC)

See Expansion of the universe. Loraof (talk) 00:04, 3 April 2017 (UTC)

In the manner of dots on a balloon being inflated. Sagittarian Milky Way (talk) 00:09, 3 April 2017 (UTC)

Or it could be us that's receding from them. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:14, 3 April 2017 (UTC)

Depending on the galaxies, there are several possibilities:

1) There is no relative "regular" motion of the galaxies themselves, so their increasing distance is solely due to the metric expansion of space.

2) Their regular motion is moving away from each other, so that adds to the expansion of space movement.

3) Their regular motion is towards each other, which may slow or even reverse their movement away from each other due to expansion. Thus, they may collide. StuRat (talk) 05:33, 3 April 2017 (UTC)

How? Apparently faster and faster. Edwin Hubble 1889 - 1953 was the first to establish that the universe is expanding. His measured observation does not prove but is consistent with cosmological theories of a bang and/or a bubble. Blooteuth (talk) 16:14, 3 April 2017 (UTC)

So, we are the center of the universe after all?Hofhof (talk) 17:36, 3 April 2017 (UTC)

Yes, but so is every other galaxy. At the 'Big Bang', all space was concentrated in one tiny point, which then expanded into (eventually) the whole of the Universe as it is now, so everywhere in the Universe is still at this 'expanded centre', and the 'place' the Big Bang happened was 'everywhere'. This may seem nonsensical, but it's demonstrated by the nature of the Cosmic background radiation.

One way to think of it is that we are only aware of 3 dimensions of space (plus the one of time) while the expansion is taking place in a 4th spacial dimension. Sagittarian Milky Way's mention of dots on an expanding balloon is a way of grasping this concept: when the balloon expands, all the dots (equivalent to galaxies containing intelligent life) move away from each other, and at each dot all the others seem to be receding from it, but there is no one centre of expansion on the (nearly) 2-D surface of the balloon – they are actually all receding from the centre of the balloon, but because the dots' inhabitents can only "perceive" the balloon's surface and not its interior they cannot "see" this centre. The actual universe is the same but with 3 dimensions; we cannot perceive the notional 4th spacial dimension in which the expansion is taking place. {The poster formerly known as 87.81.230.195} 2.122.3.250 (talk) 18:24, 3 April 2017 (UTC)

Does the extra dimension exist; is it time, or is it just a convenient analogy; or is that a meaningless question? Dbfirs 19:42, 3 April 2017 (UTC)

Though I by no means wish to preempt responses from others here, several of whom have already very skillfully summarized the core cosmological principles involved, I nevertheless, considering your inquiry, present the single best possible person to explain such a concept: [5]. Snow ^{let's rap} 05:05, 4 April 2017 (UTC)

A fourth large-scale spacial dimension is not part of any theory of cosmology that I've read. Have I not read widely enough? Dbfirs 08:55, 4 April 2017 (UTC)

Mathematically, any curved n-dimensional object can be described as embedded in some flat m-dimensional space which m > n. Such embedding may or may not be useful for doing calculations and understanding the geometry. In the context of our universe, this is sometimes done at a conceptual / mathematical level (e.g. the balloon analogy). At present, we have no evidence that the extra dimensions are "real" in the sense of being physically accessible. It may simply be a mathematical convenience with nothing from our universe able to traverse that outside space. It is worth noting however that there are some theories that posit gravitons or other hypothetical processes can move through the outside space, but right now those theories lack observational support. Dragons flight (talk) 12:29, 4 April 2017 (UTC)

So the "balloon" metaphor has some definite explanatory nicenesses, but unfortunately it presupposes a "closed" universe (one that has finite volume at any given comoving time). A "closed" universe is analogous to the surface of a balloon, one dimension up.

The general relativity equations can equally well describe an "open" universe, one that has infinite volume at any positive time after the Big Bang. This is harder to visualize, but also allows for expansion in which every point is equally the "center".

As far as I'm aware, all observations so far known are consistent with both an "open" and a "closed" universe, so the question is still, well, open. See shape of the universe. --Trovatore (talk) 07:25, 4 April 2017 (UTC)

The "open" universe can be nicely visualized by drawing a grid of dots on paper, and then a second, slightly more widely spaced grid of dots on a transparent overlay. Mark one dot to distinguish it on each grid. Mark a second dot on each grid, with the number of dots between the first and second dot being the same on both grids (e.g. 2 up, 3 across). When you arrange the transparencies so that the first dots overlap, you can clearly see that the grid is expanding from the first dot. When you arrange them so the second dots overlap, you can clearly see that the grid is expanding from the second dot - and so on for any corresponding pair of dots. Extending this to an infinite sheet is easier to visualize than considering an infinite sheet as a sphere of infinite radius. MChesterMC (talk) 08:25, 4 April 2017 (UTC)

April 3

type of orbit?

Curious to find out if there is a name for the orbit path followed by, say, a tire swing hanging from a single point. The swing follows an elliptical path but that ellipse rotates. For example, you may start out swinging the tire in an ellipse where the co-vertex is closest to a tree trunk, but eventually, the ellipse rotates so that the vertex is now closest to the tree trunk, causing the swing to eventually hit the tree. What is this called? Thank you! — Preceding unsigned comment added by CGappinger (talk • contribs) 02:58, 3 April 2017 (UTC)

Precession is what you're looking for, I think.--jpgordon^{𝄢𝄆 𝄐𝄇} 03:57, 3 April 2017 (UTC)

Not sure about that. Precession does not affect the location of the apsides. Our article apsidal precession could do with some work - the word "precession" means "moving backwards" but the phenomenon is generally referred to as "advancement of the perihelion." 81.129.14.0 (talk) 08:41, 3 April 2017 (UTC)

Precession unqualified is more commonly axial precession. Sagittarian Milky Way (talk) 13:08, 3 April 2017 (UTC)

I think the original querant is seeking the Lissajous orbit - or at the very least, an orbit with variable phase in its argument of reference longitude.

A different but related curve is the Lissajous curve.

Mathematically, these are "the same exact thing" in different coordinate-spaces - if your parametric perturbation is rotational and monotonically increasing, you get an elliptic trajectory whose apsis rotates. In practice, you might see something "similar to" a Lissajous curve any time that you have an elliptic motion that gets additionally modulated by a time-varying parameter - often caused by the physical process of precession, or by friction, or any other perturbation.

Depending on how complicated you want to make things, a tire-swing can be described as a simple harmonic oscillator, but if you displace the tire a lot by swinging very high, you can make it an imperfect (non-harmonic) oscillator; if you use a stretchy- or bendy- or heavy- rope, you add additional complexity to the equations; if you consider air resistance, rope torsion, wobbling, and rotational inertia of the tire, you get even more complications... before long, you have a "very complicated curve" for which there is no simple analytic description, and for which there probably is not a commonly-known name. The tire, in a tire swing, can move in a constrained fashion in more than six dimensions - in the x-y-z spatial directions, but also in roll-pitch-yaw, but also with additional degrees of freedom including the flexion, extension, and curvature of the supporting rope. We can parameterize the deformation of the rope along the continuum, which means we can represent this as an infinite-dimensional problem.

I feel obliged to link to the catenary equation; here's one pretty decent treatment from the astrophysics department at the University of Victoria. If you can really handle the mathematics of the catenary, you ought to be able to handle it in the dynamic case also - but by the time you digest that much equation, you will probably also realize that your stomach doesn't want to swing any higher.

I would also like to point out that if you happen to visit the Berkeley Lab, and hike around in Strawberry Canyon, there's a tree-branch suspending a swing overlooking the Golden Gate where, on any particular evening, you might find some physicists conducting experimental oscillation experiments.

Nimur (talk) 16:41, 3 April 2017 (UTC)

Mathematically, what is dubstep?

It's got to be model-able by some kind of oscillator(s) or something. It'd also be easier for musicians without technical aptitude to make if it was a relatively simple combination of only a few wobble-definition terms. Sagittarian Milky Way (talk) 17:58, 3 April 2017 (UTC)

I'd start reading at Dubstep#Rhythm and following sections, which discusses the rhythm and musical characteristics. --Jayron32 20:43, 3 April 2017 (UTC)

Also see Frequency modulation synthesis. Also of interest would be early electronic synthesizers, which often had limited capabilities but easy to tweak controls, such as LFOs. Influencial was acid house, with DJ-friendly boxes such as the Roland TB-303. Modern instruments are of course more advanced. I have done some drum and bass and dubstep using mostly the Roland MC-808. —╰]PaleoNeonate█ ⏎ ?ERROR╮ 02:39, 6 April 2017 (UTC)

Complex infrastructure programme organisation structure

How are complex infrastructure programmes such as Crossrail or HS2 in the U.K. Structured? In such programmes, government provides the funding and specify the very high level outputs, infrastructure authorities may act as the main delivery organisation for the programme and projects within in, and private sector consultancies and contractors may do the actual design and build. But at the same time all of these 3 parties are directly involved with the programme to varying levels. Is there a typical programme organisation structure for such complex programmes? 2A02:C7D:B9B7:CF00:60AE:10AF:AB2:B7C4 (talk) 20:25, 3 April 2017 (UTC)

This is not a field I know much about, but considering this question had no answer yet: I would probably begin by reading Civil engineering as well as relevant sources the article presents. This could also serve to know which keywords to use for further searches. —╰]PaleoNeonate█ ⏎ ?ERROR╮ 02:49, 6 April 2017 (UTC)

April 4

Karate

In karate, approximately how much power does it add to a punch, kick or other striking technique if you do the kiai, vs. if you exhale normally when performing the strike? 2601:646:8E01:7E0B:8C22:6F79:8644:EBB0 (talk) 04:49, 4 April 2017 (UTC)

It depends on the person. Some people strike harder if they mentally get into the whole screaming thing. Some people don't. Bruce Lee made all kinds of silly noises, but did it mostly to keep the opponent confused. Sometimes he would scream when he punched. Sometimes he would scream before he punched. Sometimes he would do his trademark "owwwww" after he punched. Nobody was saying that his punches weren't strong enough. (And before you complain that he did Judo and not Karate, note that he was a Karate instructor.) In my opinion, it is about attitude. If you use it to improve your attitude, you will perform better. 209.149.113.5 (talk) 13:24, 4 April 2017 (UTC)

• In ecky thump, it's essential.

And don't diss ecky thump, unlike Bruce Lee films, it can kill just by being watched. Andy Dingley (talk) 13:34, 4 April 2017 (UTC)

I agree with 209.149.113.5. For many martial artists, this is part of the art, and of sparring "jamming". It can also help for concentration and focus. For instance, one may use a very short and stiff sound while trying to synchronize a body movement with it for speed and power. There are also circumstances where for abdominal protection while striking (a vulnerable moment) it may be useful, and be a side effect more than intentional sounds. Of course, in martial arts culture, the reasons may also extend into metaphysics and mythology, and the anecdotes and teaching vary. Some have compared Dim mak to sneezing. :) —╰]PaleoNeonate█ ⏎ ?ERROR╮ 03:02, 6 April 2017 (UTC)

I forgot to mention it but another aspect is rhythm and motivation, especially in group training (i.e. synchronized kata repetition). —╰]PaleoNeonate█ ⏎ ?ERROR╮ 03:10, 6 April 2017 (UTC)

Growing plants in a basement

If you had to grow plants in a basement. Could you grow something edible without light, but with proper heat, nutrients and water? Could a potato (or any other root) grow under these conditions until it could nourish a human? --Hofhof (talk) 09:13, 4 April 2017 (UTC)

No, plants absolutely need light for photosynthesis. Plants don't get their energy from their 'food' as animals do, but from light, so without light they simply lack the energy to grow anything. - Lindert (talk) 09:38, 4 April 2017 (UTC)

You can certainly grow mushrooms in your basement. - Nunh-huh 09:40, 4 April 2017 (UTC)

... and they are part of the old Kingdom of Plants (as distinct from animals), but not in the clade Viridiplantae, of course. Dbfirs 10:36, 4 April 2017 (UTC)

Yes, the question was about stuff you can grow to eat, not phylogenetics. Nunh-huh 11:12, 4 April 2017 (UTC)

In that case, maybe some cultures of bacteria might be more successful, but the question said "plants" and Lindert was obviously thinking of Viridiplantae, so I was just clarifying. Dbfirs 17:14, 4 April 2017 (UTC)

I don't think it's as obvious as you seem to think. Just clarifying. - Nunh-huh 23:35, 4 April 2017 (UTC)

Could you grow bean sprouts? — Preceding unsigned comment added by Hofhof (talk • contribs) 09:42, 4 April 2017 (UTC)

Absolutely. But you'd get more calories if you just ate the beans instead. --Trovatore (talk) 10:06, 4 April 2017 (UTC)

Interesting. Bean_sprout#Cultivation says not. 196.213.35.146 (talk) 10:08, 4 April 2017 (UTC)

Does it? I don't see that there. --Trovatore (talk) 10:16, 4 April 2017 (UTC)

"The main principles are: selecting good seed (new and uniform), ensuring that light reaches the seeds..." 196.213.35.146 (talk) 10:19, 4 April 2017 (UTC)

That says that's the recommended way. It doesn't say you can't grow them without light. --Trovatore (talk) 10:21, 4 April 2017 (UTC)

Sure. But in a warm, moist and dark environment you will probably end up cultivating mold/fungus on the said beans. 196.213.35.146 (talk) 10:28, 4 April 2017 (UTC)

Hofhof asked, can you grow bean sprouts? The answer is, yes, you can grow bean sprouts. --Trovatore (talk) 10:29, 4 April 2017 (UTC)

(ec) The first few days the plant doesn't need light, because this naturally happens underground. The plant uses the energy reserves in the bean until the leaves get enough sunlight to take over. - Lindert (talk) 10:18, 4 April 2017 (UTC)

• Depending on your definition of plant, it may or may not include organisms that do not use photosynthesis, such as fungi (mushrooms). This being said, green plants "breathe" like animals do (they do not die at night), so it is not outright implausible that they could survive without light (even if that is clearly not in optimal growth conditions). Tigraan^{Click here to contact me} 10:50, 4 April 2017 (UTC)

The problem is "grow". Energy must come from somewhere if the plant is to grow significantly. This energy could be from a seed or a tuber or corm or rhizome, but, to thrive and grow normally, green plants need to photosynthesise to obtain energy. Dbfirs 11:05, 4 April 2017 (UTC)

Reiterating what Dbfirs said. One can grow rhubarb, dandelion [6] and a lot of other plants in a dark, light free, warm basement but it needs a health root stock to start with. Rhubarb Triangle states that at the end of the growing season the exhausted root stock is used for compost. The next crop needs to spend three years in the open fields first - to built up that reserve and same with dandelion etc. --Aspro (talk) 12:03, 4 April 2017 (UTC)

I can't find a reference to him now but an English lord a couple of centuries ago built some buildings in which he hoped to grow vegetables - but he didn't put in any windows! Of course it wasn't a success. Even the Romans knew one had to expose plants to the sun to grow. Dmcq (talk) 14:06, 4 April 2017 (UTC)

@Hofhof:, the above answers seem to be considering growth conditions with literally no light. Which rules out almost everything save fungi. However, most basements I've been in have some poor light (e.g. a few high windows) or can be fitted with artificial light. Given weak light or artificial light, you have many more options for plants, though many traditional crops will still perform poorly without direct sunlight. Are you also interested in those low light scenarios? Dragons flight (talk) 14:09, 4 April 2017 (UTC)

• I was asking with literally no light, but I had in mind that it might exist a plant (or similar) able to use heat as energy, that is, some sort of edible autotroph capable of chemosynthesis. Hofhof (talk) 12:50, 5 April 2017 (UTC)

If you are using lights can I suggest you used LED light? Especially ones with a lot of blue in them. Give the plants the light they can use rather than just generating heat. Dmcq (talk) 15:48, 4 April 2017 (UTC)

@Andy Dingley: That is the kind of statement that screams . None thinks you made it up and surely you remember having read it somewhere, but if I had a dollar for every time I was damn sure source X said Y when actually it did not, I would be rich. Tigraan^{Click here to contact me} 16:20, 4 April 2017 (UTC)

You want a citation for Ecky-Thump?!!! Well here is one: [7]. P.S. You may be wise to not to view the episode yourself unless you have a doctor present to provide resuscitation... Mind you, it did cure me of asthma.--Aspro (talk) 17:41, 4 April 2017 (UTC)

I'm not sure what you're doubting, but you can read all about it on the world's greatest encyclopedia. Grow_light#LEDs_(Light_Emitting_Diodes)

ApLundell (talk) 17:22, 4 April 2017 (UTC)

ApLundell just beat me to this but that article does in fact indicate that both red and blue are needed and a bit of green can also help. From looking at the web it seems cannabis growers are big users of this technology. :) Dmcq (talk) 17:28, 4 April 2017 (UTC)

Absorbance spectra of chlorophyll a (blue) and chlorophyll b (red).

The basic concept is easy to understand. Green plants are green because they reflect green wavelengths and absorb red and blue wavelengths. Only the absorbed light is used by the plant, so why waste energy on light that will not be used? Note that other Photosynthetic pigments exist, that different species of plants do better with different mixes of colors, and that even with a single species, the best color mix for for leaf growth may not be the best for encouraging flowering. Here is a technical paper on the subject:[8] (Full disclosure: I am an electronics engineer and I designed one of the more popular LED grow lights currently on the market) --Guy Macon (talk) 09:57, 5 April 2017 (UTC)

What was the nature of the LED elements in your design? It's interesting to note there has been a recent shift towards COB (chip on board) LEDs which have a much wider spectral distribution as compared to early LED grow lights which tended to be mixes of red and blue elements. 204.28.125.102 (talk) 22:50, 5 April 2017 (UTC)

Cultivated plant from Hunan, China

• File:湘潭县的莲子（淘宝搜索店铺；臻品湘莲） - panoramio.jpg

How is this plant called?--MedioWikiInit (talk) 14:08, 4 April 2017 (UTC)

Lotus? Although that's a wild guess. Andy Dingley (talk) 14:33, 4 April 2017 (UTC)

This is just a wild guess from looking at its morphology but it looks a dead ringer for something like Nelumbo nucifera.--Aspro (talk) 14:38, 4 April 2017 (UTC)

The description of the picture on Wiki Commons is "Xiangtan County lotus seed (Taobao search shop; Zhen Xiang Xiang)" (Google auto translation) Rojomoke (talk) 14:41, 4 April 2017 (UTC)

So the Wikimedia Commons description for this image, perhaps needs to be improved with an addition of an English description saying that they are locusts Agrharr... Am about to take de hameir to my spell-chequer.--Aspro (talk) 15:03, 4 April 2017 (UTC)

April 5

Weight loss and mass loss

I understand how one gains body mass: when you eat more calories than are needed by your metabolism, the mass of glucose (and substances that get converted into glucose) also increase, and the body converts some of that glucose mass into fatty cells. But what about when you lose weight, i.e. how does reduced energy consumption cause your mass to decrease? Of course I understand that the body uses the energy in its stored fat cells, but the body isn't converting mass to energy directly. Do the fat-storing cells, now empty of their energy, simply get lost in defecation? Weight loss covers dieting, medical reasons for unintentional weight loss, etc., but it doesn't address this particular issue. Nyttend (talk) 00:08, 5 April 2017 (UTC)

Generally, C_n1H_n2O_n3 plus oxygen yields water plus carbon dioxide. You lose the mass as you respire, perspire, and urinate. Fatty acid metabolism talks about the chemistry of it a bit. When you lose weight, generally the fat cells do not change in number, only size [9]. Someguy1221 (talk) 00:28, 5 April 2017 (UTC)

Someguy1221, thank you for those links! Could you expand Weight loss (ironic...) with some sources from the fatty acid metabolism article? My chemistry knowledge is good enough that I can understand the basic idea, but it's poor enough that I can't understand most of it, and I'm liable to misinterpret the sources if I try to write by myself. Nyttend (talk) 00:54, 5 April 2017 (UTC)

See also here. Count Iblis (talk) 07:30, 5 April 2017 (UTC)

Here's a video from SciShow addressing this question. --47.138.161.183 (talk) 10:22, 5 April 2017 (UTC)

Lead used to fix a connecting bar

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The caption to this picture says, "Punched lead cast in a Venice bridge wall, fixing the hard-metal connecting bar."

Why would the lead be punched?

Aside from its corrosion resistance, is it fair to presume lead is being used here since it is fairly malleable and hence could better accommodate any structural movements? Sandbh (talk) 06:49, 5 April 2017 (UTC)

The holes would have the effect of increasing flexibility at the cost of strength. So, if lack of flexibility was a problem, this might be the solution. StuRat (talk) 07:05, 5 April 2017 (UTC)

This looks like earthquake strengthening to me. Venice is somewhat prone to earthquakes. The bars keep the blocks aligned and in an earthquake, the lead compresses so that the entire structure doesn't shatter. Akld guy (talk) 07:17, 5 April 2017 (UTC)

The pieces of lead will have been hammered into the holes (the angle would make pouring molten lead too dangerous). That would not give a perfect fit against the stonework. However, punching those holes in the lead would then force the lead plugs to expand and press more firmly against the stonework. As the main purpose of the lead will be to stop water getting in between the stones, and corroding the connecting bar, the close fit is needed. The punched holes will then also allow that little bit of flexibility if the bridge moves. Wymspen (talk) 10:03, 5 April 2017 (UTC)

These answers are exceptionally plausible, thank you very much. Is this kind of thing mentioned in the literature anywhere? Dr Google has so far not yielded anything. The closest I haven gotten is to lead wool used for caulking which seems to a related concept, capitalising on the corrosion resistance and malleability of lead.

Epistemology and ontology of medical sociology (sociology of illness and health) and health psychology.

Hello,

I am looking at the two subdisciplines of health psychology and medical sociology. I note that they are subdisciplines of their parent disciplines that both study illness and health and have some overlap (methods etc). I have read the relevant wiki articles and note that m.s. seems to take a macro approach, situating the person within their social and cultural context while health psychology seems to look more at a persons thoughts and beliefs (in general). After having read the wiki articles I have gone on to read some research on the topic but have been unable to find clear definitions for both disciplines' epistemology and ontology. Could anybody help me out or direct me to articles I can read about these? I would like to see the (different) ways in which these disciplines understand the world.

Any help or direction towards relevant studies and articles would be greatly appreciated. BW, --129.215.178.207 (talk) 13:37, 5 April 2017 (UTC)

I think you have hit on the basic difference: health psychology studies medicine and health using the tools and ideas from the field of psychology. Medical sociology studies studies medicine and health using the tools and ideas from the field of sociology. The differences between these two stem from the differences between the fields of psychology and sociology. Understanding the different viewpoints of these general fields will inform the differences of the specializations. Sociology and psychology do have very different epistemologies. Medical anthropology, a specialization of anthropology, is the third member in this cluster of disciplines. --Mark viking (talk) 05:53, 6 April 2017 (UTC)

How fast could an 18-wheeler cab do 0-60 with an aerodynamic shell attached?

The higher power-to-weight ratio ones without that little cabin in the back for sleeping. How fast could it accelerate if it had an aerodynamic shell attached and was geared for 0-60 instead of pulling trailers? And why does a Mack truck cab have up to 2,060 foot-pounds of torque which can pull 300,000 pounds (including itself and what's in it, with an overweight permit) but a Ford F-450 has 925 foot-pounds of torque and can't pull anything close to 300,000/2,060*925 pounds? Sagittarian Milky Way (talk) 19:26, 5 April 2017 (UTC)

Think you could look at Truck Dragsters and truck racing. Also trucks have double gearboxes so one can change up (just like in a car) to 60 or more – very quickly.--Aspro (talk) 22:24, 5 April 2017 (UTC)

What does the defibrilator do to the heart when it febrilates?

How does it stop the chaos which happens in the heart cells (myocardiocytes) in the micro level? I've checked the article here and it's not clear to me. — Preceding unsigned comment added by 95.133.184.142 (talk) 16:25, 5 April 2017 (UTC)

Defibrillation literally stops the heart. The intent is the equivalent of a computer reboot: to stop undesired behaviour, it halts all activity and resets itself. I can't tell you what happens on the micro level. Even out article states that he exact mechanism of defibrillation is not well understood.Mingmingla (talk) 19:12, 5 April 2017 (UTC)

Remember how The Fonz could walk up to a jukebox, rap it with his knuckles, and it would start playing? I think it's kinda like that. Only half joking. --Trovatore (talk) 19:23, 5 April 2017 (UTC)

Moved from the Language Refdesk Roger (Dodger67) (talk) 19:27, 5 April 2017 (UTC)

Vaccines

If someone had a high risk of getting exposed to water contaminated by fecal matter, would any vaccine, combination of vaccines, or prophylactic medicine help keep healthy? --Hofhof (talk) 21:27, 5 April 2017 (UTC)

Yes, this was clearly demonstrated in a documentary a shown on NGC a few years ago. The presenter took a dive in the severely polluted Ganges river in India and became ill due to all sorts of pathogens in that river. A course of antibiotics cured the disease, the reason why the locals don;t get ill is because of acquired immunity due to being exposed to the polluted river. So, gradual exposure will help to build enough immunity to keep healthy. Count Iblis (talk) 21:40, 5 April 2017 (UTC)

Filter sizes between 0.1 and 0.4 microns will remove bacteria from water but will not remove viruses, though new “hollow fiber” technology can remove viruses as well. Water that has been boiled for 1 minute is safe to drink after it has cooled. The CDC recommends these and other measures to travellers. Blooteuth (talk) 21:53, 5 April 2017 (UTC)

It's clear that not drinking contaminated water to start with is the best solution. But I had in mind a scenario where this is not possible. For example, in the case of development workers, troops, and foreign correspondents. Hofhof (talk) 22:08, 5 April 2017 (UTC)

There are vaccines against some of the most common waterborne illnesses, including cholera, hepatitis A, polio (you probably got that one) and typhoid. Vaccines are not 100% effective, but it will at least reduce your chances of infection if exposure is inevitable. Many serious waterborne illnesses have no approved vaccine, however, such as shigella. Someguy1221 (talk) 22:17, 5 April 2017 (UTC)

I haven't got polio. Why would I? Hofhof (talk) 22:31, 5 April 2017 (UTC)

"you probably got that [vaccine]" Someguy1221 (talk) 22:34, 5 April 2017 (UTC)

In the case of troops, they are issued water purification tablets as part of their kit. 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 06:38, 6 April 2017 (UTC)

April 6

Extraterrestrial government and economy

Has anyone ever speculated what types of governments and economies extraterrestrials might have?Uncle dan is home (talk) 00:30, 6 April 2017 (UTC)

If you count sci-fiction, then definitely, lots of authors. --Hofhof (talk) 01:08, 6 April 2017 (UTC)

Yes in 1000s and 1000s of Science Fiction books, short stories, films and various other media. This is still one of my favorites. MarnetteD|Talk 01:10, 6 April 2017 (UTC)

Could a natural breast look like fake?

In the same way that fake boobs sometimes look natural, could the contrary happen, and perfectly natural boobs look as if they were fake? Like being too round?--Dikipewia (talk) 03:06, 6 April 2017 (UTC)

Are you the one that asked about unwanted touching? ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:39, 6 April 2017 (UTC)

Equilibrium question - Physics

A point body in static equilibrium will remain at rest or continue moving with a constant velocity. This means net force on a point mass is zero if moving with constant velocity in space. Thus does the equilibrium status of a point mass moving with constant velocity alter if brought to rest with the help of external force? Unbalanced force(s) change the equilibrium status of a body, therefore, is the aforementioned external force on a point mass, which changes its position to stationary unbalance?2001:56A:7399:1200:7436:C9CB:D58F:2D2A (talk) 05:01, 6 April 2017 (UTC)eek

What is the difference between the cells of the electrical conduction system to the rest heart muscle cells?

According to the article here "The conduction system consists of specialised heart muscle cells, and is situated within the myocardium. There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular, fast, or slow heart rhythms.". In what they unique compared to the rest muscle cells? according to other articles here the muscle cells of the heart (no differentiation) has the feature of automatically. 93.126.88.30 (talk) 06:16, 6 April 2017 (UTC)