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February 5

When the freezer or refrigerator breaks, what do I do with food in it?

OK, so something is wrong with my refrigerator and freezer. I have no idea what, but I am calling the repairman tomorrow. There is nothing that I can do about it now, overnight. Basically, both parts (the fridge and the freezer) are not "cold enough" and something is causing the refrigeration and freezing to not work properly. Dead motor? Who knows? So, my question: do I have to throw all of that food out or will it be OK? And the food in the freezer, can that simply be re-frozen again? Right now, the freezer "seems" like a refrigerator (in temperature). Thanks. Joseph A. Spadaro (talk) 07:36, 5 February 2016 (UTC)

The answer depends on the items that have defrosted. General advice is NOT to re-freeze, and this should be strictly followed for any meat items that have thawed, especially if they have been thawed for some time. Some foodstuffs can be refrozen, but if in doubt, either eat or throw out. Ice cream doesn't re-freeze. Please note that this is opinion, not expert advice on a health issue. If in doubt, throw it out. Dbfirs 07:46, 5 February 2016 (UTC)

Mostly frozen dinners. Joseph A. Spadaro (talk) 08:27, 5 February 2016 (UTC)

Specifically, refreezing ice cream leads to formation of ice crystals, so it no longer has that smooth texture you would like. However, when you are ready to eat it, you can let it melt and basically make a milk shake. (Also make sure it hasn't been left warm long enough for bacteria to grow.)

Bread can be refrozen, but doing that too many times will lead one side to be soggy and the other to be stale.

Soup can be refrozen with no bad effects, although when you reheat you may want to boil it to kill off any bacteria.

Most of those frozen dinners are probably OK. I'd cook them normally, smell and taste them, and if they seem OK go for it. StuRat (talk) 16:23, 5 February 2016 (UTC)

So would I, especially if they have never reached room temperature, but I wouldn't advise anyone else to do this, just in case ... Dbfirs 18:58, 5 February 2016 (UTC)

Also, if you are a smoker, or otherwise have an impaired sense of smell and taste, have somebody else smell and taste it for you. StuRat (talk) 15:26, 6 February 2016 (UTC)

The idea that you can't refreeze meat or other foodstuff is common, but it's a misconception (which doesn't mean that all thawed food can be refrozen safely or without changes in texture and taste), see [1] [2] [3]. Sjö (talk) 09:43, 5 February 2016 (UTC)

It's worth mentioning that some home-owner's or renter's insurance will cover you for the loss of food in your freezer when it fails and can't be repaired within a few hours. If you plan on claiming, take a photo of the food packages that you are tossing out. SteveBaker (talk) 14:25, 5 February 2016 (UTC)

Some things that might cause a freezer/fridge to work, but at reduced cooling, are loss of coolant, coils in back covered with dust bunnies, or air flow to them reduced in other ways, or something wrong with the thermostat. You might try turning the thermostat to the lowest temp, and blowing a fan on the coils, until the repairman arrives. Also try not to open the door often, and you could pack ice or maybe dry ice inside to keep it cool. (Make sure the regular ice has a safe place to drain.) Also, if there was ice buildup inside the freezer (in a non frost-free model), ensure that you don't get puddles underneath when that melts. StuRat (talk) 16:31, 5 February 2016 (UTC)

So now it is the case that the repairman cannot come for several days (Monday). That will leave the food for more than three days (all of Friday, all of Saturday, all of Sunday; plus part of Thursday and part of Monday). Will those frozen dinners still be good at that point? Or is that too much time? Thanks. Joseph A. Spadaro (talk) 19:13, 5 February 2016 (UTC)

If you could keep them at fridge temperature or below, then they might still be OK, but if they remain near room temperature for three days, then they should definitely be thrown out (those you haven't already eaten). Does your insurance not cover this loss? Can you find someone else with spare space in their freezer? Can you buy any ice and a large cool-box? Dbfirs 19:20, 5 February 2016 (UTC)

Thanks. I had assumed that the repairmen would come out the same day; I guess that's not the case. They are not free until Monday and, of course, there is the intervening weekend days. I will bring the food over to some relatives who live very close by. Thanks. Joseph A. Spadaro (talk) 20:54, 5 February 2016 (UTC)

I suggest using the freezer itself as the "cool box". It's reasonably well insulated and you won't lose the existing "coolth" when doing a transfer. The downside is that the freezer isn't meant to hold water, so you should use dry ice instead of normal ice. You can get that at many grocery stores and even gas stations. You could also ask neighbors if you can stow some food there until Tuesday. StuRat (talk) 21:14, 5 February 2016 (UTC)

Coolth μηδείς (talk) 22:43, 5 February 2016 (UTC)

Yes, I would like this to become a common word. While physics tells us that "coolth" is only an absence of warmth, that doesn't mean we can't have a word for it. By comparison, you can say "it's dark outside", not having to resort to something as ugly as "their is a paucity of light outside". Of course, there is "cold", but like warmth is less extreme than hot, so is coolth less extreme than cold. StuRat (talk) 23:31, 5 February 2016 (UTC)

1540s, from cool on the model of warmth. It persists, and was used by Pound, Tolkien, Kipling μηδείς (talk) 02:47, 8 February 2016 (UTC)

... and the OED shows usage from 1547 onwards, but it does also comment: "Now chiefly literary, arch., or humorous". Dbfirs 10:04, 6 February 2016 (UTC)

• Joseph, 10 lb bags of ice cost $2 each. You also presumably have neighbours who can hold stuff temporarily? My parents lost power on the June 23rd storm that devasted South Jersey, leaving them without power for 72 hours. The following morning I bought as much ice as I could find, and we stuffed their upright freezer, ice on top, food on the bottom racks, and towels in the bottom. My dad cooked a rib-roast and a ham sooner than he had planned. But there was no food lost, and great rejoicing when the power returned. Food that is thawing is in a transition state where the temperature stays constant. As long as the meat is not fully thawed it is still at 32F. The problem with repeated semi-thawing is that the meat fibre break down, and ruin the texture of the meat. For hot dogs, sausage, and ground beef that doesn't matter. But whole cuts will get ruined if frozen solid repeatedly. μηδείς (talk) 02:41, 6 February 2016 (UTC) μηδείς (talk) 02:41, 6 February 2016 (UTC)

I know the OP's question concerned food in a freezer but I wanted to point out meat isn't some sort of simple liquid melting. In something like meat, conduction can be slow and I don't think radiation or convection are significant factors for heat transfer to the internal. So you can get a temperature diffential, you shouldn't expect all the meat to be at 32 F just because the middle isn't thawed. That's partly the reason many sources recommend against thawing at room temperature, the other key one is probably that people may leave the food out too long after thawing (well these are related); and the third is that people may thaw it somewhere they later use for prepration of food that won't be cooked or otherwise risk cross-contamination.

This source [4] suggests the actual difference when thawing is at 70 F (~21.1C) is fairly low, the surface temperature reaches 53 F (~11.7 C) which while in the danger zone it doesn't have to be held there for that long before the middle is thawed to be a concern. But reading it carefully suggests it would be useful to check the source which I think is an old issue of [5] which I couldn't find until I realise they had a copy [6] (I thought this was just a link to the earlier article). It seems they also tested thawing at 84F (~28.9 C) and surface temperatures there reached 63 F with the largest turkey (65 F with the smallest), and these were a concern particularly for the largest size since it took longer than the theoretical lowest 4 G time to thaw. [7] is possibly also of interest although I couldn't find read it given the age and rarity.

Interesting enough, having read that and [8] it seems that thawing in the fridge can actually result in more Pseudomonas spoilage bacteria given the longer times. Not at levels to cause safety concerns but which may negatively effect quality. Also it seems like wrapping with sufficient newspaper (or whatever) can significantly reduce the temperature differential.

The take away message would be that you definitely shouldn't assume your food was all at at 0 degrees C just because it wasn't completely thawed if it's meat or something else with poor heat transfer but that it probably isn't as a big a concern as most general sources [9] [10] [11] [12] make it out to be provide you don't leave it too long. The complicating factor if it's a big cut of meat (or a whole bird of poultry) which you don't want to cut, is how you know whether it is thawed completely. Probably partly the reason why it's often only recommend in industrial sectors where they can monitor room temperatures, times and carry out tests to determine precisely how long.

Also these all remind me how contradictory and poorly supported a lot of food safety advice tends to be. Although I know one of the reasons is because food safety agencies want simple rules of thumb people can follow like [13].

I'm pretty sure concerns over improper thawing are also partly the origin of the never re-freeze myth. (In fact two or all three of the sources provided by Sjö mention that you should only re-freeze if thawed in the refrigerator.) Even if the levels of growth aren't enough to be a concern if the food is properly cooked, if you keep doing thawing it that way eventually you're going to get concerning levels. The others concerns with re-freezing would be quality loss and people not probably accounting for time whatever the temperature. E.g. a small cut of raw meat which should often only be stored in the fridge for 6 days and may be completely thawed within a day or less in the fridge. So if it's left for 4 days then frozen then thawed and left another 4 days in the fridge then refrozen then thawed and left another 4 days before cooking, it's now probably been at least 9 days.

Nil Einne (talk) 05:15, 6 February 2016 (UTC)

Thanks, Nil Einne. When I was referring to meat as thawing, I meant that it still had solidly frozen meat detectable under the surface, and frost on the outside. I was happy to take the opportunity of that squall to explain why I had about 10 gallons of frozen water jugs in the freezer to my mother--mostly to retain the coolth--who complained they were unaesthetic. Luckfully my dad was a trained pipefitter. μηδείς (talk) 01:17, 9 February 2016 (UTC)

Thanks. Yes, I have neighbors/relatives who live downstairs. So I placed all my stuff there for the time being. Thanks. Joseph A. Spadaro (talk) 04:46, 6 February 2016 (UTC)

You, lucky, lucky bastard! 03:12, 7 February 2016 (UTC)

Thanks, all. Joseph A. Spadaro (talk) 19:07, 8 February 2016 (UTC)

Crane Collapses in Lower Manhattan, Killing at Least One Person

• htt p://www.nytimes. com/2016/02/06/nyregion/crane-collapse-lower-manhattan.html

At least one person was killed on Friday morning when a crane collapsed in Lower Manhattan, the police said.

The crane came down shortly before 8:30 a.m., toppling onto Worth Street and spanning more than the entire length of a city block, officials and witnesses said.

If you see the video taken by some office Workers shortly before the collapse, you hear very strange violin-like noise made by the fallen crane. What made the weird noise? Bending metal? Vibrating cables? -- Toytoy (talk) 17:13, 5 February 2016 (UTC)

The only weird sound I hear is the sound of a saw (or similar power tool). Is that what you mean? Sławomir
Biały 17:39, 5 February 2016 (UTC)

Here's the link. I suspect the cable was rubbing the framework due to the stress of the crane failing, I'll ask around. μηδείς (talk) 22:39, 5 February 2016 (UTC)

Sounds like shearing metal to me. It's an unfamiliar sound because we don't often hear that much metal shear at once. StuRat (talk) 23:33, 5 February 2016 (UTC)

Yes, I played this for my father (a retired engineer) and he said he had seen crane and tower collapses, but they did not make this noise. He suggested either a cable rubbing the framework or a broken strut rubbing the framework could have caused such a resonance. To me the noise sounds sweet, not like the tearing shriek of Godzilla, so I am going with resonance in a cable. μηδείς (talk) 01:05, 6 February 2016 (UTC)

Each collapse will be different. There isn't necessarily shearing metal in all collapses, either. In some cases, the crane just falls over. StuRat (talk) 15:30, 6 February 2016 (UTC)

To my ears the noise sounds like it is coming from inside the room with the people talking/partying. (Something to do with the echoes inside the room and high/low band pass filtering, though I can't say exactly what, gives me that impression) Can someone confirm it actually was produced from outside the window? I'd just expect it to sound ... different from out there. Wnt (talk) 02:47, 6 February 2016 (UTC)

If the sound is coming from outside, my guess is it's a warning hooter sounded by the crane when stability limits were exceeded. Akld guy (talk) 02:53, 6 February 2016 (UTC)

I go with Wnt. That noise is way too loud to be coming from the crane at that distance through ?double glazed windows. Even when the crane hits the ground there is an almost imperceptible thud, compared with outdoor witnesses who described it as 'like a bomb going off'. The other thing that requires explanation is the very similar repetition of the noise 3 or 4 times while the crane is in different positions. Unless a clip taken from outside the building turns up likely we'll never know. But it's nice for everyone to have a guess. Richard Avery (talk) 08:10, 6 February 2016 (UTC)

One commentator of the video (reply to leandro5455) says:

To all those wondering about the beeping or loud sound in the beginning... That is the sound of the truss structure of the crane failing and creating vibrations throughout the entire 500' length. If you look close you can see the sound increase and decrease with the speed of the end of the boom. This is also why the sound stops once the end really gets moving. I'm sure the sound was extremely loud on the other side of the insulated pane glass office windows. These things are unbelievably strong and only fail in extreme circumstances. As of right now it looks like the cause was wind. In short it was the death cries of the crane warning people to pay attention and get out of the way.

One factor against the sound originating from the crane, beyond the loudness, is that I can't find any descriptions in stories about the collapse of the noise (they mention the sounds at it crashed etc). Another thing you can learn from reading the comments is that the video was taken by construction workers (confirmed by [14]) and the building they were in was under the construction, so the possibility it was a power tool of some sort inside may not be unlikely as it would seem. (There seems to be a window where they're looking out so I presume the building was already fully enclosed.)

Also from reading stories of the collapse it seems the crane was being lowered at the time, so there's also the possibility it was some sort of warning siren.

Nil Einne (talk) 13:05, 6 February 2016 (UTC)

I don't think a power tool would be nearly that loud. Also, it wouldn't turn on by itself. StuRat (talk) 15:19, 6 February 2016 (UTC)

"turn on by itself"? Nil Einne (talk) 15:25, 6 February 2016 (UTC)

Oh, I see I misread that bit. I thought the power tool was supposedly on the falling crane, but now I see you meant it to be in the building. StuRat (talk) 15:27, 6 February 2016 (UTC)

Yes, the issue mentioned by others before I replied was that it was quite loud compared to other sounds relating to the crane (which I agree with) so perhaps it's inside the building. Under normal circumstances it'll be fairly uncommon for the to be a power tool inside a building but since these were construction workers and the building was probably under construction (or at least there were renovations going on) the possibly of a power tool inside the building is a lot more likely. Nil Einne (talk) 15:31, 6 February 2016 (UTC)

At around 1:05 in the video, you can see that this was a mobile crane, on catapillar tracks, and that it simply tipped over. It doesn't look like it broke with some loud tearing of metal or anything because the tracks are flipped upside-down, implying that the entire machine toppled as one more or less rigid structure. That seems unlikely to have happened if something major simply snapped close to the base and that the sound was tortured metal. Once it started to fall, most of it was simply under free-fall in gravity - so there would be less stresses on the structure at that point.

So I'm with the idea that this was some kind of a warning siren or an unrelated power tool inside the building. Unfortunately, the sound cuts off before there is enough movement in the crane to make for an obvious doppler-shift in the audio, so it's not easy to tell whether the noise came from the jib structure or from the base of the crane.

The thing that kinda suggests that the power tool hypothesis is good is that it cuts off around about the time that the guy holding the camera starts yelling about what's going on - which is probably when the guy with the power tool would have shut it off to come and look. It's hard to imagine why a warning siren would cut off at all. SteveBaker (talk) 16:18, 6 February 2016 (UTC)

Yeah, I don't think the sound has anything to do with the crane. Sounds like an angle grinder or similar to me (sander, buffer, etc.). Pitch is modulated as the power tool contact the surface at different pressures, then stops as you say, when the shouting starts. SemanticMantis (talk) 16:58, 6 February 2016 (UTC)

Is there any kind of open source software for analyzing echoes in sound? Listening to the recording I imagine there was a wall, oh maybe 20 feet behind the person speaking, and most of the voices and the "musical instrument" were clustered near but not outside the entrance from a hallway there. That's a lot of guessing though... I bet there are congenitally blind people who could do 10000% better at that kind of analysis. Still, is there something that can analyze sound and determine the timing of the echoes, correlate the L and R channels, to produce some kind of crude map? Then you might find a best fit for the "musical instrument" on the map. I bet the damned NSA has software like this that's good enough to practically make video of the inside of your house from your phone calls.... Wnt (talk) 00:18, 7 February 2016 (UTC)

Detection of echo(s) in recorded sound is a type of Autocorrelation analysis that finds the cross-correlation of the signal with itself at different time delays. It can be applied to estimate musical pitches and tempo; it was part of the attempted (inconclusive) analysis of the John F. Kennedy assassination Dictabelt recording, and I have used it to measure varying buffer delays on VoIP links. When the source sound is uncontrolled then accidental autocorrelations greatly confuse the analysis. Extracting directional autocorrelation from a stereo room recording would only be theoretically possible with long integration of fully controlled stimulus signals, such as Chirps used in compressive Sonar, and have front/back ambiguity. Even supposing demonic assistance, the intrusive domestic mapping project that Wnt wagers the National Security Agency can do would involve very noticeable disruption to telephones and get echo maps that are irretrievably scrambled by grating lobes (no article yet). AllBestFaith (talk) 16:10, 7 February 2016 (UTC)

February 6

List of people who have walked on the Moon

I just stumbled upon this article: List of people who have walked on the Moon. So, is it true that no one at all has ever walked on the moon, other than people from the USA? That seems odd to me. Joseph A. Spadaro (talk) 06:48, 6 February 2016 (UTC)

Well, it shouldn't be too much of a surprise, given that only the US has ever sent successful missions to the Moon, and the age of international cooperation in space travel didn't really get going until after Apollo was over. To me, maybe the sadder stat is that no one born after 1935 has ever walked on the Moon. I hope that will change. --Trovatore (talk) 08:15, 6 February 2016 (UTC)

Quibble: Only NASA has attempted manned Moon missions (as far as we know), but other projects have successfully landed there. —Tamfang (talk) 08:26, 6 February 2016 (UTC)

The Iron Sky link is fantastic. Cannolis (talk) 09:06, 6 February 2016 (UTC)

As for why, the only serious competitor to NASA, until recently, was the Soviet Union, and they didn't want to put in the massive resources it would take to get to the Moon, especially just to become the 2nd to land somebody there. They preferred to put their resources into places where they could be first, like first ship into space, first dog, etc. After all, the purpose of their space program was to prove to the world that they were #1, not #2. StuRat (talk) 14:52, 6 February 2016 (UTC)

Arguably, that's what the US was doing too...which explains why the USA never went back there after the Apollo program was ended. The USSR had plans to send men to the moon - they just dropped them once they knew they wouldn't get there first. (See Soviet manned lunar programs). If they'd kept to their schedule, they might actually have beaten the US to getting a man onto the moon by a matter of months - but the unexpected death of their chief rocket engineer, Sergei Korolev, due to cancer - and then financial cutbacks - threw enough delays into the program that allowed the USA to beat them to it...and within a very short span of that happening, the plans were dropped and buried as if they'd never happened. SteveBaker (talk) 16:09, 6 February 2016 (UTC)

And, as far as the first ship into space, there's been the suggestion that some in the US didn't want to be first, both to allow the Soviet Union to establish the precedent that overflying other nations was not a violation of airspace, and to gain the massive taxpayer support needed for future programs. StuRat (talk) 16:23, 6 February 2016 (UTC)

Got a ref for the second claim, on airspace? SemanticMantis (talk) 16:55, 6 February 2016 (UTC)

Here's a discussion at BBC News. StuRat (talk) 19:52, 6 February 2016 (UTC)

Even before we went, no small number of Americans thought it was a waste of taxpayer money. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:11, 6 February 2016 (UTC)

Yes, this is my point. After seeing that space ships were possible, and that the Soviet Union could launch them, this changed the minds of most US taxpayers. Later, JFK's speech certainly helped, too. StuRat (talk)

Many, especially in the older generation, argued it was a waste of taxpayer money even after we had achieved it. Their typical response to that accomplishment was, "So what?" ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:29, 7 February 2016 (UTC)

Yeah, I never paid it much mind. I think I had assumed that other nations (especially Russia) had done so, just with much less fanfare than the US's "first" men up there. Joseph A. Spadaro (talk) 18:11, 6 February 2016 (UTC)

Well, the Soviets tried to land a man on the moon in the 60s, but they gave it up because their chosen booster had the rather unfortunate habit of exploding every time they tried to launch something with it (the second time, it blew up on the pad, completely destroying the launch complex in what was both the largest explosion in the entire history of rocketry and believed to be the largest man-made non-nuclear explosion ever, with an approximate explosive yield of seven kilotonnes TNT equivalent). Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:18, 6 February 2016 (UTC)

OMFG, that's almost half the yield of Hiroshima! I suppose that's not good for the launch complex. Wnt (talk) 00:37, 7 February 2016 (UTC)

Video of failed Cygnus CRS Orb-3 mission

To be fair - many new (and ultimately successful) rocket programs go through phases of blowing up...(although perhaps not as disasterously as the N1 did). It only takes one teeny-tiny design flaw to make that happen - and quite often one explosion is sufficient to enable the designers to figure out what needs to be fixed. So just because one or two prototypes had problems, you can't extrapolate from that to say that it would never have worked had they kept working on it. The very next launch attempt could have succeeded perfectly. Just so you don't think the N1 was unique in that regard, a commercial launch at the Wallops Island launch site (under NASA auspices) left a 60' wide, 30' deep crater where the launchpad was used to be. That happened in October 2014. — Preceding unsigned comment added by SteveBaker (talk • contribs) 15:59, 7 February 2016 (UTC)

Funny you should mention the loss of that Orb-3 flight of Orbital's Antares rocket, as its first stage was powered by Aerojet AJ-26 engines, which are refurbished, 40-years old, Soviet NK-33s which were originally intended for the N-1 moon shot rocket discussed above. An engine failed due to an explosion in its LOX turbopump. During the investigation, it was leaked that Foreign Object Debris had been detected in the turbopumps, possibly from desiccant left in a tank. The final report confirms the FOD, but states that "there is no clear forensic evidence that FOD directly or indirectly led to the E15 [engine] failure", and also reports on inadequate design robustness and a manufacturing flaw in the engine. See NASA Independent Review Team Orb–3 Accident Investigation Report Executive Summary. -- ToE 02:51, 8 February 2016 (UTC)

I'm shocked that your school paid so little attention to the history of the manned space program. Of course, I lived through it, so it was front-page all the time, until Congress stopped funding Apollo four missions short of its original intended duration. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:09, 6 February 2016 (UTC)

@Baseball Bugs: What time frame are we talking about? Late 50's and early 60's? Joseph A. Spadaro (talk) 03:09, 7 February 2016 (UTC)

Yes. Of course that wasn't "history", it was "current events". ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:27, 7 February 2016 (UTC)

OK. That was "before my time". And I guess it lost all of its "sexiness" (newness) as a topic in school by the time I got there. Joseph A. Spadaro (talk) 19:44, 7 February 2016 (UTC)

I've noticed that there's a hole between current events and history. For example, if you were in high school during Watergate, it was probably discussed as current events. And if you were in high school by the 1980's, it might have made it into the history books by then. But if you were in high school in the late 1970's, it was no longer a current event, and wasn't yet in the history books, either. StuRat (talk) 19:54, 7 February 2016 (UTC)

posting by banned user removed.

Apollo was expensive, but not that expensive. Per Apollo program#Costs, each Saturn V launch in 1970 cost $375M, against total outlays that year of $195B (see here). I don't know whether the $375M was a marginal or average cost; obviously average cost will be much higher than marginal.

The total cost of the Apollo program altogether was estimated in 2010 as $109B in 2010 dollars. Not cheap, but that's the whole program, from 1961 to 1972. --Trovatore (talk) 20:00, 8 February 2016 (UTC)

The shuttle launches cost about $1.2 billion each (also in 2010 dollars) which sounds cheap...but the $109 billion that Apollo cost is a bit harder to adjust for number of launches because although there were only a dozen or so Saturn V launches - Apollo did a bunch of Saturn I and Little Joe launches before the moon landings - and of course developed a ton of technology and launch facilities that the Shuttle program later relied upon. The estimate for the money saved by NOT flying Apollo's 18, 19 and 20 amounted to about $500 million per launch (again, 2010 dollars) - but you can't use that to say that Apollo missions cost half what the Shuttle did because the Apollo hardware had already been built - and that some of it was ultimately re-used for Skylab.

This means it's unfair to suggest that Apollo was more expensive than the Shuttle program...or vice versa. There is simply no way to divorce spending on the former from benefits to the latter. SteveBaker (talk) 20:43, 8 February 2016 (UTC)

Can any problem be broken down into easy to understand parts?

Is there any problem that cannot be understood when you break it down to its constituents? Can you treat a big problem as a collection of small chunks of problems? And basically, understand any level of complexity with a little brain/computer? --Scicurious (talk) 14:48, 6 February 2016 (UTC)

So far we haven't been able to understand intelligence just by breaking it down, let alone consciousness. We understand neurons, but that doesn't seem to be enough. More generally, any emergent property seems to require looking at the whole system, as it is somehow literally more than the sum of it's parts.

Then there are things we could theoretically understand, if we could identify all the parts, but there's just too many and they are just too small. For example, accurately predicting the weather a year from today. StuRat (talk) 14:54, 6 February 2016 (UTC)

Firstly, we need to restrict ourselves to problems that can be solved. We know that in mathematics, there are fundamentally unsolvable problems. So let's restrict ourselves to problems that can actually be solved.

The question in the title is "Can any problem be broken down into easy to understand parts?" - but I think there are some small, minimum problems that can't be broken down any further. Ultimately, it starts to get difficult to break down "What is 1+1?" into sub-problems - the answer 'just is'. In mathematics, some things are taken to be "axioms" - and you can't break down an axiom...it just "is". However, when you get down to those smallest constituents, I think that most people should be able to understand them. So, I think the answer to this one is a tentative "Yes"...assuming the problem is at least in principle solveable.

The hard part is in the the next question: "Is there any problem that cannot be understood when you break it down to its constituents?". Imagine what happens in a computer program. The "problem" is inherently broken down into the tiniest steps that even a totally mindless computer can understand - things like addition, multiplication, moving a number from one place to another, testing a number to see if it's zero, jumping to a different place in the program. Those steps are definitely small enough that more or less anyone could understand them individually - no single machine-code instruction that a typical computer can run is beyond the capability of most human beings with a knowledge of basic arithmetic to comprehend.

If your theory is correct - then by examining these microscopic "problems" one by one - I can understand anything that a computer can be programmed to do.

But if someone writes a program to (lets say) play chess - and we give the list of individual machine-code instructions to someone who can't play chess. Would breaking down the program of playing chess well into (literally) a billion tiny addition/move/test/jump steps help you to understand how to play the game at grand-master levels?

In this case, breaking down the problem made it much harder to understand. In order to deduce the rules for playing chess, I don't want the ultimately broken-down version of the problem. I want the high-level description.

So, theoretically - yes, the information is in there - but in practice, definitely not!

SteveBaker (talk) 16:00, 6 February 2016 (UTC)

The theoretical way to make a perfect chess-playing program, by looking at every possible move and response by the opponent, to the end of the game, and selecting whatever move leads to the fewest loss and tie scenarios and most wins, is pretty easy to understand. However, that turns out to be impossible for a program (other than at the endgame), due to too many possibilities to calculate. So then you get more complex programs that are difficult to understand by a human. StuRat (talk) 16:17, 6 February 2016 (UTC)

As phrased, there's no simple answer, and no uncontroversial answer, but I'll give you some refs you might like: Emergent phenomena are basically things that are not simply sums of constituent parts, and Stu is right to bring that up as something that doesn't fit well into your scheme. Nonlinear dynamics in general don't lend themselves to clean decomposition. Divide and conquer only works really well for linear and additive systems/problems. Extremal_principles_in_non-equilibrium_thermodynamics and deterministic chaos are two examples of things that aren't that amenable to solving smaller chunks to get a bigger solution. Kolmogorov_complexity is also fun to think about in this context. Self organization is another good example of the need for some Holism in our inquiry. Here's a nice comic on the topic from SMBC [15]. It's telling that analyze literally means "to cut apart" - it's a very useful method and we've done wonderful things with it. But it is not the only way, and all problems are not tractable via decomposition or deconstruction. So while your questions are a little vague and ill-defined (what is a problem, what is understanding?), that's ok, these questions must necessarily be so. My WP:OR answers to your questions are: "Yes, Often, and No." :) SemanticMantis (talk) 16:19, 6 February 2016 (UTC)

I have a related question. The law of entropy is an "emergent property", but isn't it a consequence of Newton's law of motion? If a high speed particle hits a low speed particle, their speed is going to be distributed evenly, isn't this what causes the 2nd law? — Preceding unsigned comment added by Money is tight (talk • contribs) 00:10, 7 February 2016 (UTC)

In the classical mechanics that existed before Isaac Newton, Momentum is conserved in collisions between particles. Momentum is the product of mass and Velocity. Velocity is a vector quantity posessing a direction as well as a magnitude (while <speed> and <mass> have no direction) so momentum is likewise a vector. In 1687 Newton caused to be published in Principia:

Lex. II.

Mutationem motus proportionalem esse vi motrici impressae, & fieri secundum lineam rectam qua vis illa imprimitur.

This is the second of Newton's laws of motion which essentially expresses conservation of momentum in terms of its time derivative Force and of the time-derivative of velocity which is Acceleration. Today we state that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object. AllBestFaith (talk) 15:27, 7 February 2016 (UTC)

February 7

Man with no brain

I've seen a photo of a man with no brain yet he functions normally. Does this give evidence for existence of the soul, or consciousness is beyond the brain? — Preceding unsigned comment added by Money is tight (talk • contribs) 00:07, 7 February 2016 (UTC)

Can you link us to this photo? The complete absence of a brain, or anencephaly, is lethal at or just after birth. It is true that people can have remarkably large brain defects and function reasonably well in daily life, but this is not 'no brain'. As for your other questions, the soul does not exist, and there is no evidence for conciousness 'beyond the brain'. Fgf10 (talk) 00:13, 7 February 2016 (UTC)

Whether there are souls is a theological question outside the scope of this Reference Desk. Wikipedia does discuss the beliefs of various religions and other belief systems about the soul. Robert McClenon (talk) 00:22, 7 February 2016 (UTC)

No, it's a scientific question on the Science refdesk. There is no evidence for souls in science. Whatever various works of fiction claim is of no consequence. Fgf10 (talk) 01:08, 7 February 2016 (UTC)

The existence of souls, or not, is a matter of opinion, not of science. ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:25, 7 February 2016 (UTC)

At the science desk? Don't be ridiculous. The soul, as described in various works of fiction, is incompatible with the laws of physics as we understand them, so unless we've got it very wrong, according to science it doesn't exist. End of. Fgf10 (talk) 12:49, 7 February 2016 (UTC)

The so-called "laws of physics" are a human interpretation. "...as we understand them..." is the key point. They are their own kind of religion. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:57, 7 February 2016 (UTC)

I've gone far afield with this recently, so I won't again, but I should note that science has not disproved the existence of the soul, nor has it provided a satisfactory explanation of qualia. That said, I have not heard of anyone able to use skeletal muscles in a controlled manner who does not have some apparent central nervous system to control them. This is biology, so there is no law of nature that would prevent the autonomic nervous system, enteric nervous system etc. from growing efferents and somehow learning to control muscles without a brain present; or even preventing cells of the skin, muscles etc. from expressing proteins that lets them spread action potentials and think; but there's no evidence they have the capability and by this point such things would seem extraordinarily, extraordinarily unlikely, as would most other brain-free processes of control. Wnt (talk) 00:29, 7 February 2016 (UTC)

Science also hasn't disproved the existence of the Flying Spaghetti Monster. So what? Fgf10 (talk) 01:08, 7 February 2016 (UTC)

Then it could exist. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:57, 7 February 2016 (UTC)

There are various photos of men who are missing most of their brains and still function normally. This sometimes the result of extreme hydrocephaly or physical trauma to the brain. But rest assured, these people still have some brain left. If you find anyone claiming a human can function with literally no brain, you are being lied to without a doubt. Someguy1221 (talk) 02:49, 7 February 2016 (UTC)

Just realized this is an election year. You'll likely be seeing lots of men with no brains walking around and even talking. Someguy1221 (talk) 10:39, 7 February 2016 (UTC)

Well, let's go with malfunctioning brains - for the sake of science! SteveBaker (talk) 15:22, 7 February 2016 (UTC)

Or perhaps they just never figured out how to use them... Double sharp (talk) 04:37, 8 February 2016 (UTC)

So you're advocating that they figure out how to use their brains using...um...their brains? What could possibly go wrong?! :-) SteveBaker (talk) 17:57, 8 February 2016 (UTC)

https://www.google.com.au/?gfe_rd=cr&ei=kK-2VufIBcbN8geWxYHYBg#q=half+head+man — Preceding unsigned comment added by Money is tight (talk • contribs) 02:45, 7 February 2016 (UTC)

Some of those photos are real - but a lot of them are very bad photoshopped images. We do know that people can and do survive with very little brain tissue remaining...there have been cases reported where a person survived with just a 1" thick layer of brain surrounding a fluid-filled void. But with no brain at all - that's utterly impossible. The brain handles a bunch of functions such as the control of breathing - that you simply can't do without.

As for the soul - no, science has not disproved the concept - but it also hasn't disproved the concept of green aardvarks playing pianos on the far side of the moon...that doesn't mean that we have to assume that they exist. The default hypothesis in this case is that souls don't exist (and neither do those aardvarks) and since you're asking this question on the science reference desk - the scientific answer is that since we have no evidence for the existence of a soul, it is meaningless to ask whether a man without a brain (who couldn't be alive anyway) would or would not have one. SteveBaker (talk) 15:35, 7 February 2016 (UTC)

Are you telling us that The Clangers did not exist? I am gutted!;-) DrChrissy ^(talk) 15:47, 7 February 2016 (UTC)

The clangers were (a) not green and (b) evidently played slide whistles rather than pianos...but aside from that, of course they existed! SteveBaker (talk) 05:28, 8 February 2016 (UTC)

Like in arguments about Wikipedia consensus, arguing about default hypotheses involves a lot of gaming about what is "default". "Flying spaghetti monster" is usually applied as an argument for the non-existence of God, but it's one thing to assume the burden of proof is against a very specific made-up religion, and something else (say) to conclude confidently that the universe was not designed, has no plan or purpose, that the answer to why people really feel things and really see beauty in it is that actually they don't, and that everything about the universe, including the laws of mathematics, is purely random. ("But where did random come from? Isn't that just begging the question?") Perhaps the better approach here is to ask -- what, specifically, scientifically, do you mean when you say the soul doesn't exist? Because maybe that's not part of the definition... Wnt (talk) 18:14, 7 February 2016 (UTC)

The default is to presume that what we can measure is "real" and what we can't measure has to be demonstrated indirectly. No such demonstration of a "soul" has ever been made - and, to the contrary, when we stick someone's head into a brain scanner, we see it light up in an appropriate and consistent manner when the person thinks about different things and in different ways. There is sufficient complexity in the brain for "emergent behavior" to appear - so there is no reason to assume that there is "something else". That's not to say that there isn't a "soul" - but merely that this shouldn't be the default hypothesis.

There is no evidence that whatever religion you're considering was not "made up" too - in fact, because there are so many religions in the world - many of which are sharply contradictory - the evidence is that even if one of them turns out to be correct, at least 99% of religions must be nonsense. Wondering what the odds of 99% of religions being incorrect rather than 100% of them provides additional reason to eliminate them from the default hypothesis.

As for "beauty" - you make the absolutely classic (and exceedingly naive) mistake of presuming that atheists see no beauty in the universe - and nothing could be further from the truth. The beauty is in all of the amazing mechanisms that emerge from the simplest of representations. That the key laws of physics can be written on the front of a T-shirt (I have one) - and that is enough to understand very nearly all of it. That, to most scientific thinkers, is beauty. That the leaves of a tree are the result of random evolutionary processes that result in the near perfect optimisation for capturing sunlight - is incredible. That flowers have beautiful markings on there petals that humans can't see because they are in the UV spectrum - and that the plant evolved to put them there to help bees to figure out how to orient themselves as they land to do pollination. Please - don't tell me that you need religion to see beauty - that's complete and utter bullshit. If all I had to believe is that a magician waved his magic wand and it all popped into existence - the world would seem to be an arbitrary, ridiculous, foolish place - and much of the beauty would evaporate.

The laws of mathematics are not "random" - they may all be deduced from the most simple axioms imaginable - you're entirely mistaken if you believe that.

The randomness of the universe comes about from quantum randomness and the randomness that comes about in some systems that are susceptible to sensitive-dependence-on-initial-conditions...Chaos theory. So we're very well aware of what those sources are.

What is meant by "the soul does not exist" is not a question I really need to answer. I have not been provided with a definition for this term - it's a vague piece of description that's conveniently never pinned down. Without a definition, it's nothing more than a word. So we have not discovered any evidence for a thing that's vaguely described in the first place.

The argument that a lot of people believe in something, so it must be true has been disproven more times than I can count. An enormous number of people believe that vaccination causes autism - does that make it true? Actually - no. It's been tested beyond reasonable need - and it's not true. Despite that, only 52% of Americans believe that vaccines don't cause autism. 68% believe in god (in some form or another). Does that make them right?

SteveBaker (talk) 05:28, 8 February 2016 (UTC)

I'll leave this article, about a neighbour of mine when I lived in Barnsley, here. --TammyMoet (talk) 16:00, 7 February 2016 (UTC)

Yes, I suspect the OP may be thinking about something like the case Tammy mentions. As for "the soul doesn't exist" I don't believe we can say that either. The definition of a soul is "the spiritual or immaterial part of a human being or animal, regarded as immortal"[16] and all we can say is that there is no scientific evidence for that to be the case. However, we still don't have a complete theory of everything and so it is just possible that there are things or mechanisms that exist that we don't yet know about. And just to make my position clear, personally, I am 99% sure there is no God as visualised by religious people and no afterlife. I'm quite happy with that as, if I'm right, when I die my consciousness will come to an end and I won't have to worry about it. However, like everything else in life, I always entertain the possibility that I may just be wrong (a very remote possibility in this case), and if I am, it will be interesting to find out what comes next. There is the (also very unlikely) possibility that the universe was created by some intelligent entity but, if it was, then I am sure they don't really care less whether we worship and pray to them or ignore them completely. Oh, and if it does all turn out to be an experiment run by the white mice then I'm in deep shit - but that's anther story. Richerman (talk) 12:43, 8 February 2016 (UTC)

The desire to believe that your life won't just suddenly just "end" is quite powerful. You don't have to resort to religion and the concept of a "soul" to get past that though. There is always the (MUCH more worrying) Quantum suicide and immortality hypothesis - I'm kinda hoping that's one hypothesis which turns out not to be true because it might just imply eternal (albeit religion-free) damnation! Even without the many-worlds hypothesis, you can get pretty much the same result if the universe turns out to be infinite and the weak anthropic principle is acceptable to you. Another one that I like is the concept of reincarnation - in which at the moment of your death, you are reborn as another human being - although you'd have absolutely no memory of your earlier life. Many people find that to be a much more comfortable situation than just "fade to black...nothingness" - although to all measurable tests, the outcome would be identical. So if you're OK with "no-memory-transfer" reincarnation, you have an unfalsifiable hypothesis that's every bit as good as any religious view. Then we have the Simulation hypothesis (another theory that I'm quite fond of) - and so maybe the universe will get a blue-screen and wind up being rebooted? SteveBaker (talk) 18:12, 8 February 2016 (UTC)

What is the meaning of the word "lead" in context of ECG?

I understand that is one of 12 electrodes, but I'm asking about the meaning of the word. I opened dictionary and I saw many meanings, but I'm not sure which one is the right.93.126.95.68 (talk) 00:08, 7 February 2016 (UTC)

Lead is essentially used interchangeably with electrode, not any specific one. Fgf10 (talk) 00:15, 7 February 2016 (UTC)

Thank you, but I'm not sure if you're right because I know that a typical ECG machine has 9 electrodes while it result give 12 leads. (aVL+aVR+aVF are augmented leads without their own electrode, so actually you can not call them electrodes, then the word lead can not be used interchangeably with electrode.)93.126.95.68 (talk) 00:41, 7 February 2016 (UTC)

In some versions of English, 'lead' is a synonym for 'wire' or 'cable', as in 'extension lead'. Not sure whether that helps though. Akld guy (talk) 01:02, 7 February 2016 (UTC)

That is exactly the relevant meaning here yes. As per a quick read, the electrodes mentioned actually physically use the same electrodes as some of the main 9, but are referenced differently, so are essentially 'virtual' electrodes. REF Fgf10 (talk) 01:14, 7 February 2016 (UTC)

See our Electrocardiography article. The leads run from the machine and have detachable electrodes [17] [18] which are stuck on to the patient's skin with a conductive gel. Richerman (talk) 13:03, 8 February 2016 (UTC)

Do all the muscles of the body have origin and insertion?

Do all the muscles of the body have origin and insertion? and if they do have, doed the heart (as considered as muscle) also have origin and insertion? 93.126.95.68 (talk) 00:31, 7 February 2016 (UTC)

Hmmm, also External sphincter muscle of male urethra, external anal sphincter, iris sphincter muscle (sort of, though you can argue that starts as smooth muscle which we know is different). In the case of the anal sphincter there actually *is* an insertion, for one layer - might be worth looking deeper into the embryology to see if the circular layer is a late specialization in development? Wnt (talk) 00:49, 7 February 2016 (UTC)

I believe the tongue does not.DrChrissy ^(talk) 00:51, 7 February 2016 (UTC)

From our article:

"The eight muscles of the human tongue are classified as either intrinsic or extrinsic. The four intrinsic muscles act to change the shape of the tongue, and are not attached to any bone. The four extrinsic muscles act to change the position of the tongue, and are anchored to bone."

It goes on to describe which bones the four extrinsic muscles are anchored to. So for the tongue as a whole, half yes and half no. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 15:04, 8 February 2016 (UTC)

In genetics, sex can be dominant?

In genetics, sex can be dominant? I mean to male or female, does one of them can be dominant just because of his sex? 93.126.95.68 (talk) 00:56, 7 February 2016 (UTC)

If you mean dominant in the Mendelian sense, then one could argue that the answer is yes when sex determination is chromosomal. In placental mammals, one could say that male is dominant in the Mendelian sense because a single Y chromosome determines male sex. In birds, one could likewise argue that female is dominant in the Mendelian sense. If you mean something other than the Mendelian sense, please clarify. — Preceding unsigned comment added by Robert McClenon (talk • contribs)

Yes, User:Robert McClenon's comment is basically correct for mammals, insofar as the presence of the Y causes male characteristics, whatever the number of the X chromosomes. See XXY. That doesn't apply for certain birds and insects, e.g., though. μηδείς (talk) 02:20, 7 February 2016 (UTC)

To be nitpicky, it's specifically the gene SRY that causes development of male phenotype in mammals when expressed. SRY is normally located on the Y chromosome, but it is possible for mammals to have a Y chromosome and still be phenotypically female, to varying degrees, like if the SRY gene is broken, or if there are other conditions like androgen insensitivity. --71.119.131.184 (talk) 07:14, 7 February 2016 (UTC)

How rare is this? Are they any more likely to have male traits than XX women? What happens if both the mother and the father give a Y chromosome each? Sagittarian Milky Way (talk) 07:59, 7 February 2016 (UTC)

You might like to read this if you haven't already done so. Dbfirs 10:04, 7 February 2016 (UTC)

Are there any XY females who are actually capable of getting pregnant in the first place? Certainly it wouldn't be the ones with complete androgen insensitivity syndrome, because they don't have ovaries or a uterus. But I don't know for sure that it isn't possible in some other way. --Trovatore (talk) 23:18, 7 February 2016 (UTC)

I don't think people with 100% XY have gotten pregnant, but there are rare cases like this that come pretty close. - Lindert (talk) 23:34, 7 February 2016 (UTC)

Very interesting. The abstract says that the daughter got a Y from the father, but doesn't say, as far as I saw, whether the mother had any viable Y-bearing ova. Is it known whether that's possible? --Trovatore (talk) 23:47, 7 February 2016 (UTC)

Any mammalian embryo with no X chromosome is nonviable, as the X chromosome contains many essential genes. Embryos with abnormal chromosomes inevitably get created as a result of errors in meiosis. Down syndrome is a well-known example, but most chromosomal abnormalities are lethal and cause the pregnancy to spontaneously abort. The Y chromosome is not essential, which is obvious as half of mammals don't have one. Because of this, evolutionary pressure inevitably reduces the Y chromosome over time (see the article for details). --71.119.131.184 (talk) 10:58, 8 February 2016 (UTC)

Hmmm, I suppose you could say that maleness is a recessive lethal with some phenotypic effects in the heterozygote. (That link should go to lethal allele, but that article was written by someone who defines that term altogether differently than what I'm familiar with!!!) Wnt (talk) 18:20, 7 February 2016 (UTC)

You might like reading about the evolution of sex and anisogamy. SemanticMantis (talk) 15:45, 8 February 2016 (UTC)

Date of official information on the name of element 113

I could have asked the question any time I wanted to, but I chose now because we've reached the first time in a week when doing a Google News search on "ununtrium" doesn't reveal anything less than a week old. Can anyone predict the date I'll get official info?? Georgia guy (talk) 01:18, 7 February 2016 (UTC)

Only the people at RIKEN and IUPAC will be able to answer that one. Fgf10 (talk) 01:23, 7 February 2016 (UTC)

Odors emitted by the Feces and Urine of Mammals and Birds

Where can I find material on the intensity of odors emitted by the feces and by the urine of various mammals and birds? Thank you.Simonschaim (talk) 10:49, 7 February 2016 (UTC)

We don't have an article specifically on this topic (although Category:Feces might prove useful). It should be covered in any general work on woodcraft, and a web search on animal-specific terms ("bear scat", "fox scat", etc) will usually come up with the appropriate details. Tevildo (talk) 12:03, 7 February 2016 (UTC)

Bile contributes to the smell of feces. StuRat (talk) 18:13, 7 February 2016 (UTC)

This is a tough one. I mean... we all know from experience how much it can vary based on diet. Beyond that, intestinal microflora. If you take some lab animals and do a poo sniff-off, mostly you've learned what the lab techs are feeding the animals. I'd be wary of general statements. Wnt (talk) 18:23, 7 February 2016 (UTC)

It might be difficult to find information on the intensity per se, but articles the OP might want to look at include Pheromone, Vomeronasal organ and Flehmen.DrChrissy ^(talk) 18:31, 7 February 2016 (UTC)

As a long-time pet owner, I would point out that the intensity and nature of the smell of animal pee depends on its age and storage condition. Cat urine on cat litter which is less than a day old is different from cat urine deposited on a plastic bag or piece of fabric on the floor behind a couch which is not discovered for a week. The question seems like a readily quantifiable one.It would be surprising if no date had been collected and published. Subjects could give subjective ratings of odor strength for standardized samples under well defined experimental conditions, and we could learn the relative intensity of either a constant volume of parakeet/lizard/hamster/cat/rattlesnake/dog/human/deer/lion/bear/dolphin/horse/hippopotamus/elephant/whale urine or feces, or the relative subjective odor strength of a normal deposit of said substances. Edison (talk) 21:19, 7 February 2016 (UTC)

Skatole is responsible for much fecal odor, and the term may help you find more quantitative assessments. SemanticMantis (talk) 15:44, 8 February 2016 (UTC)

Oil drilling -- env. impact

What substances/materials (if any) which are involved in oil drilling (particularly in offshore oil drilling) are classified as highly toxic? In particular, which are toxic not only by ingestion, but also by skin contact and/or inhalation of vapors? 2601:646:8E01:9089:F88D:DE34:7772:8E5B (talk) 12:01, 7 February 2016 (UTC)

Here's a list of the types of chemicals likely to be used during the drilling of offshore wells - not much there on toxicity though. The oil itself may be the most toxic chemical that people may come into contact with. Mikenorton (talk) 12:11, 7 February 2016 (UTC)

And that last material is only moderately toxic. 2601:646:8E01:9089:F88D:DE34:7772:8E5B (talk) 12:16, 7 February 2016 (UTC)

Found some data for benzalkonium chloride (used in oil drilling as a corrosion inhibitor) -- it's pretty toxic, rather more so than crude oil. Benzalkonium_chloride#Toxicology 2601:646:8E01:9089:F88D:DE34:7772:8E5B (talk) 12:39, 7 February 2016 (UTC)

Oil drilling, part 2

If there's an oil spill at sea and it catches on fire by itself, is it ever put out or is it universal practice to let it burn? (I know, for example, that oil spills are sometimes deliberately set on fire as a last-ditch cleanup measure.) In what circumstances, if any, should it be put out? Is it a conceivable scenario where a burning oil slick is first extinguished and later deliberately ignited again as part of the disaster response? 2601:646:8E01:9089:F88D:DE34:7772:8E5B (talk) 12:21, 7 February 2016 (UTC)

NOAA page on in-situ burning. Mikenorton (talk) 12:26, 7 February 2016 (UTC)

Crude oil does not inflame itself. Setting it on fire deliberately is most likely motivated by "saving" near coastlines, which else have to be cleaned up later. In contrast to coasts our oceans and atmosphere have always been treated as a dump for toxic wastes anyway. --Kharon (talk) 12:46, 7 February 2016 (UTC)

I did not mean spontaneous combustion, I meant accidental ignition from a stray source. 2601:646:8E01:9089:14B5:216D:30B1:F92 (talk) 07:34, 8 February 2016 (UTC)

Near earth approach of 2013 TX68 in March 2016

Asteroid 2013 TX68 is due to make a near Earth approach next month. Per the article and news stories, it was only observed for 3 days in its previous approach in 2013, and is too dim to be seen when distant from the earth. Stories say it could come as far as 9.2 million miles or as close as 11,000 miles,(and equivalent 2 digit precision in metric units) but that it can't possibly hit the earth. Christian Science Monitor says "There is no possibility that this object could impact Earth" in 2016, per a NASA press release. Its nearest approach time is uncertain ("sometime between March 3–8, 2016",per the Wikipedia article) and we can't see it until it is within a couple of days of closest approach. So if the largest number is "9.2 million miles," apparently to two digits of precision, how can NASA be so certain that 11,000 miles is the closest possible approach? Is this just false confidence to avoid public alarm? I've seen a lot of confidence intervals, and "11,000 to 9,000,000" as stated in some news articles is an odd one. It's like saying "4505500 miles plus or minus 4494500 miles" if we take the average as the midpoint. Then they give odds on its closest approach on future occasions, but an approach to tens of thousands of miles would cause a huge deflection in its direction, with the deflection dependent on the closeness of approach. How does the certainty that the closest approach is 11.000 rather than zero square with the a large magnitude of the farthest approach?, Given apparent uncertainty about the nearness of this approach. how can there be much certainty about the next approach? Edison (talk) 14:29, 7 February 2016 (UTC)

JPL has a graphic that shows possible points of closest approach given the orbital uncertainties. It seems that these points are restricted to a plane that appears to be well constrained and does not contain Earth. The closest point of that plane to our dear planet is 11,000 miles away and thus gives the minimum possible approach distance. --Wrongfilter (talk) 14:56, 7 February 2016 (UTC)

In other places (HERE for example) you can see the calculations are being done to higher precision than the Christian Science Monitor quoted...in a news item, journalists rarely want to write hugely precise numbers because they are hard to read and assimilate.

But I agree with User:Edison - we know the plane in which the rock orbits with great precision - and we know that this plane only comes within 11,000 miles of Earth - but we have much greater uncertainty about where 2013TX68 will be within that plane at the point of closest approach.

Perhaps an analogy would be useful: It's kinda like worrying about cars on a fast stretch of a flat, straight road going right past your house. You have no idea whether they'll be driving at 30mph or speeding way over the speed limit at 90mph - so your error margin in their speed is huge. But you do know - with great precision and high confidence - that they'll stay within that narrow corridor prescribed by the edges of the road. So if you're walking home along the sidewalk and you see a car that's 5 miles away on the horizon coming towards you. You don't have any good idea at all of how close it'll be when you reach the safety of your home...but you're confident that it's not going to hit your house with almost complete certainty. If asked how close the car might get to you as you open your front door, the larger number would be "a couple of miles...maybe?" and the smaller number would be the distance from your house to the edge of the road (18 feet 7 inches).

Your error margin on the larger number is enormous - but you still know with near certainty that your house is safe.

SteveBaker (talk) 15:16, 7 February 2016 (UTC)

Thanks. Confidence of it being in a plane 11,000 miles from earth is a fine explanation for the amazing figures cited.It makes perfect sense. But wouldn't a possible pass 11,000 miles from earth deflect, it putting it in a different orbit/plane? It sounds like they are forecasting approaches years in the future based on a scant 3 days of observation 3 years ago. Te graphic from JPL is odd, since it basically shows two rows of dots, and nothing between them. Is there an explanation for that? Edison (talk)

That depends on how exactly that figure was created. I assume it was some sort of Monte Carlo simulation - randomly pick a possible value of starting parameters out of the possible range in 2013, calculate the orbit, plot the position of closest approach in 2016. Now, if they picked the extremes for the starting parameters (values around, say, the 1σ contour) rather than the best-fit values, those would map to something like an ellipse in the output parameters, i.e. this graphic. So the lack of dots inside these two rows would be due to them not bothering making the computation for those values. But this is just me guessing, I can't back this up with a publication or so. The deflection during this approach will certainly affect the prediction for the next one, and it will depend on how close this approach will actually be. --Wrongfilter (talk) 21:45, 7 February 2016 (UTC)

Hmmm - I wonder if one row of dots comes from the sunward-leg of the orbit and the other as it returns from the sun, heading out towards deep space? That would explain two neat sets of numbers like that. That's a guess though. SteveBaker (talk) 05:02, 8 February 2016 (UTC)

The orbit of the asteroid is known to an accuracy of a few thousand kilometres. The accuracy isn't the same at every point of the orbit or in every direction, but that's the order of magnitude. The uncertainty in the semi-major axis translates into an uncertainty in the orbital period, and in the 2.5 years since it was last observed this accumulated into a quite large uncertainty in the phase of the asteroid's orbit of about 14 million kilometres. In other words, we know quite well where the orbit is and that Earth will pass at 17000 km away from the orbit, but we don't know where the asteroid will be at that moment. I assume the figure published by JPL indeed results from a Monte Carlo simulation. One row of dots comes from the asteroid passing Earth's orbit ahead of Earth, the other row comes from the asteroid passing Earth's orbit behind Earth. PiusImpavidus (talk) 11:11, 8 February 2016 (UTC)

sources of oxidants in natural shale gas reservoirs

A few years ago I came across a lot of industrial presentations on natural gas reservoirs, especially shale gas, and something that was mentioned is that shale gas reservoirs can become "overmature" where the hydrocarbons become CO2. This was puzzling to me because I couldn't figure out what could be oxidizing the gas only after the organic material has been sitting there for around 200 million years, when it appears to be fine from the 50 million year period onwards.

Two questions: 1) What are the source of reducing agents that reduces longer-chain fatty acids and carboxylic acids to methane? Why can't we exploit these reducing agents directly? 2) What are the source of oxidizing agents that oxidise methane to CO2 deep in the ground, underneath the bedrock?

Yanping Nora Soong (talk) 17:18, 7 February 2016 (UTC)

I'm not familiar with this, but the first few sources I found [19] [20] [21] [22] give me the impression that there is an "oil window" and a "gas window" in which kerogen (of which there are apparently four types) is cracked under heat and pressure. I see different estimates for the window, doubtless because some specifics of how they are measured are different, but they say roughly 50-100 celsius at 2-4 km depth produces oil, maybe 100 to 150? 200? more? celsius at 3-6 km depth produces gas. Very hot gas undergoes "secondary cracking" that the first source says can first produce wet gas, and

"Metagenesis marks the final stage, in which additional heat and chemical changes convert much of the kerogen into methane and a carbon residue. As the source rock moves farther into the gas window, late methane, or dry gas, is evolved, along with nonhydrocarbon gases such as carbon dioxide [CO2], nitrogen [N2] and hydrogen sulfide [H2S]. These changes take place at temperatures ranging from about 150°C to 200°C [302°F to 392°F]. These stages have a direct bearing on source rock maturity." (This appears to be cited to Peters KE, Walters CC and Moldowan JM: The Biomarker Guide, 2nd edition. Cambridge, England: Cambridge University Press, 2005) Wnt (talk) 18:01, 7 February 2016 (UTC)

I'll pass the ball to someone else at this point. Wnt (talk) 18:01, 7 February 2016 (UTC)

To build a bit on Wnt's excellent information. Initially organic matter is trapped in fine clays and silts. As the organic rich clay is buried under millions of years of sediment accumulation, the clay turns into shale and the organic material transforms into kerogen. As it is buried deeper and deeper, the heat and pressure transform (or mature) the kerogen into oils and eventually gas (by combining hydrogen with carbon to form long chain {ex. octane} and eventually short chain hydrocarbons {ex. methane}). Once all the hydrogen in the organic matter has combined with carbon to form hydrocarbons, increasing heat and pressure will never create any additional hydrocarbons and the reservoir is overmature.

Obviously we can't apply 150-200 C or the pressure at 3-6km depth (about 5,000-10,000 psi) to convert organic matter into CO2 on the surface, or at least not economically.Tobyc75 (talk) 21:59, 8 February 2016 (UTC)

Are all stars main sequence stars at some point in their life-cycle?

Do all stars belong either to the main sequence stars, have once been main sequence or will inevitably become main sequence stars?

See stellar evolution. It appears from that article that all protostars that are large enough to fuse hydrogen (and thus become stars rather than brown dwarves) will enter the main sequence for some period of time. Robert McClenon (talk) 20:28, 7 February 2016 (UTC)

are there compounds which are poorly soluble in aliphatic hydrocarbons (e.g. cyclohexane) but dissolve well in aromatic ones (like benzene or toluene)?

I note that neutral (zwitterionic) L-DOPA is weakly soluble in water but even less soluble in diethyl ether or chloroform. However, would it be more soluble in aromatic solvents? Yanping Nora Soong (talk) 21:25, 7 February 2016 (UTC)

Buckminsterfullerene is substantially more soluble in aromatics than in aliphatics. DMacks (talk) 21:33, 7 February 2016 (UTC)

Really how important is fruit?

I've gone months of having a bowl of fruit nearly every morning and months of having no fruit at all yet feel no different during that time. 2.103.13.244 (talk) 22:29, 7 February 2016 (UTC)

We cannot give actual medical advice here, but you might be interested in the underlying reasons for medical and public-health organizations publishing various food pyramids and promoting balanced diet. See whether it's strictly about the types of foods or the types of nutrients or the trade-offs in a real economy or other cultural/political environment. DMacks (talk) 22:33, 7 February 2016 (UTC)

Nutritional advice is not medical advice (or everyone who publishes a diet book would be arrested for practicing medicine without a license), so we are free to reply. Fruit does have some good stuff, like vitamin C in citrus, antioxidants/phytochemicals in berries, lycopene in tomatoes (technically a fruit), and healthy fats in avocados, but you can also get those from other things. So, in that sense they aren't essential. On the other hand, if eating fruit for dessert stops you from eating something far worse, that's a real plus. StuRat (talk) 22:39, 7 February 2016 (UTC)

Fruit also has soluble and insoluble fiber. On the downside, it does have a lot of sugar (at least if you're talking about the fruits most people think of as fruit, meaning not tomatoes, not green beans, etc). A lot of people track "added" sugar, but I think this is one of the tradeoffs DMacks is talking about — your body can't (or I expect it can't) tell whether the sugar is "added". But the experts don't want to discourage people from eating fruit, so they don't emphasize tracking total sugar. --Trovatore (talk) 22:46, 7 February 2016 (UTC)

Sugar isn't too bad in whole fruits, where it gets to be a problem is with juices, where all the fiber has been removed and the sugar concentrated, or where you actually add sugar, like sugar on grapefruit, whipped cream on berries, or even more sugar added to "juice". StuRat (talk) 23:09, 7 February 2016 (UTC)

Sugar is sugar. Well, certainly there are different kinds of sugar, but the dominant one in fruit is fructose, which is the same thing people get upset about in high-fructose corn syrup.

I don't think your body can tell whether you ate the sugar as part of a whole fruit or not. But the fruit has other benefits, which is why the experts don't want to discourage you from eating it. --Trovatore (talk) 23:36, 7 February 2016 (UTC)

Reducing the amount of sugar (by eating one orange versus the juice of 10), and increasing the amount of fiber in order to slow digestion, both reduce the sugar spike, which is what leads to most of the health problems associated with sugar. Also, it takes more energy to digest whole fruit, and some of the sugar can be burned in that way. StuRat (talk) 17:49, 8 February 2016 (UTC)

Avoiding sugar in "too sweet" fruits is a recommendation in the low-carbohydrate diet community. Also, not all sugars are equal. Glucose is more likely than fructose to reach cells throughout the body rather than get metabolized in the liver. Yanping Nora Soong (talk) 01:04, 8 February 2016 (UTC)

Thanks for the replies but I'm wondering why I feel exactly the same whether or not I eat fruit. Is the effect of eating fruit everyday to extend your life by a few years or are there present-day benefits? 2.103.13.244 (talk) 02:44, 8 February 2016 (UTC)

That's hard to answer unless we know what you're eating instead of fruit (or conversely, what fruit is replacing when you eat it). If you're eating good, nutritious stuff instead of fruit you're doing fine. If you're eating cheeseburgers and Twinkies and such instead of fruit, it will probably catch up to you over the long term, though not necessarily in a few days or even weeks. Shock Brigade Harvester Boris (talk) 04:34, 8 February 2016 (UTC)

Below, our OP also indicates an aversion to vegetables too...so I think that it's unlikely that there is good stuff being eaten in place of fruit. SteveBaker (talk) 17:43, 8 February 2016 (UTC)

Most of the damaging effects of unhealthy food have no immediate and obvious symptoms. For example, plaque forming in your arteries may not be apparent until a heart attack. StuRat (talk) 17:53, 8 February 2016 (UTC)

February 8

marshy gas from mines

as during mining ,the marshy gas are evolve ,why this happen? please give the scientific reason.https://en.wikipedia.org/w/index.php?action=edit&preload=&editintro=&preloadtitle=&section=new&title=Wikipedia%3AReference+desk%2FScience&create=Ready%3F+Ask+a+new+question%21# — Preceding unsigned comment added by Shahjad ansari (talk • contribs) 02:23, 8 February 2016 (UTC)

See Methane#Occurrence. AllBestFaith (talk) 10:55, 8 February 2016 (UTC)

See also firedamp. The methane is produced as coal is heated (due to progressive burial) and some of it is retained in the rock when the coal becomes uplifted sufficiently to mine, where it can be a problem. Mikenorton (talk) 21:42, 8 February 2016 (UTC)

Formula for lens

give the formula equation for lens ,in which one longitudinal part areat n1 refractive index , second part at n3 refractive index and lens of n2 refractive index.https://en.wikipedia.org/w/index.php?action=edit&preload=&editintro=&preloadtitle=&section=new&title=Wikipedia%3AReference+desk%2FScience&create=Ready%3F+Ask+a+new+question%21# — Preceding unsigned comment added by Shahjad ansari (talk • contribs) 02:32, 8 February 2016 (UTC)

Sorry, we don't do your homework for you. Check the articles Refraction and Lens (optics) for the info you need. 2601:646:8E01:9089:14B5:216D:30B1:F92 (talk) 10:35, 8 February 2016 (UTC)

Possible to change taste buds in adulthood?

I'm 20 and hate the taste of vegetables unless it's been thoroughly cooked and/or mixed with other flavours. Could I change that and if so is there a known method? 2.103.13.244 (talk) 02:54, 8 February 2016 (UTC)

Apparently it's in your genes. Googling "why some people vegetables" throws up some interesting links, including this one which suggests you need "bitter blockers".--Shantavira|^{feed me} 11:08, 8 February 2016 (UTC)

Technically that's a medical diagnosis, and we aren't supposed to do that. It's certainly possible that there would be some other mechanism in this case besides genetics, which is almost never 100%. Wnt (talk) 12:41, 8 February 2016 (UTC)

Technically, that isn't a medical diagnosis, it's a biology reference. See User:Kainaw/Kainaw's criterion. Unless we're telling someone that a) they have a disease or b) what the disease is likely to do to them personally or c) how to treat their diseases, there is no problem with providing answers about human biology. --Jayron32 15:09, 8 February 2016 (UTC)

"Apparently it's in your genes" diagnosis "this one which suggests you need "bitter blockers" treatment. μηδείς (talk) 18:55, 8 February 2016 (UTC)

Have a look at our long, detailed, and well-referenced article taste. It's complicated, and involved taste buds, but also psychology, nutritional needs, evolutionary past, culture, childhood development, exposure, etc. etc. Most people I know enjoy some foods at age 40 that they did not at age 20. Here's a selection of articles that discuss aspects of how taste perception can change with age [23] [24] [25]. Here's a freely accessible article that discusses a bit about how children's diet preferences are shaped by the adults around them, and you might find it interesting background reading [26]. We have some references for treatment of [[27]] and also Avoidant/restrictive_food_intake_disorder#For_adults, so I would look at the refs there if I wanted to learn more details about methods for expanding my taste preferences. SemanticMantis (talk) 15:40, 8 February 2016 (UTC)

My experience is that a lot depends on how the food is cooked. Generally (as our OP mentions), brief cooking retains flavor and long cooking destroys it. Generally, short cooking is what people want because they crave the maximum amount of flavor - but I suppose that if you don't like those flavors then the reverse might be the case. Unfortunately, cooking for too long destroys much of the nutritional benefits of eating vegetables - and also destroys any crunchy, textured sensations and reduces them to an unpleasant mush. Honestly, I'd recommend re-visiting the taste of lightly cooked (or even raw) veggies...and if that's still unpleasant, dump them into some kind of sauce that you like. A chili or curry-based sauce will annihilate the taste of almost anything! Also, it's a horrible generalization to say that you don't like "vegetables" - there are hundreds of different kinds out there - and they don't all taste the same. Gone are the days when you had a choice between carrots/broccoli/cabbage/peas/french-beans/corn. Now you can get 'baby' versions of lots of things - there are 50 kinds of beans out there - there are leafy greens of 20 different kinds to choose from - there are things like asparagus (which used to be ruinously expensive - and now isn't), avocado and artechokes to play around with. It would be really surprising if you hated all of them, and even more surprising if you hated all of them no matter how they were prepared. Modern cuisine encourages us to mix weird, contrasting things together - so go ahead and mix jalapeno peppers, a little melted chocolate and peas (yes, really!) - or cook your cabbage in orange juice instead of water (one of my personal favorites!) - or mix nuts and fruit into a green salad. There is no "wrong" answer here.

I grew up in an environment where veggies were low in variety, and invariably over-cooked. When I married my first wife (who is an excellent French cook) - my eyes were opened to the incredible array of better options out there. SteveBaker (talk) 17:24, 8 February 2016 (UTC)

My experience changing what I drink may be helpful. In my 20's I drank Mountain Dew (high sugar soft drink). Then I switched to herbal tea, but needed lots of sugar in it to make it palatable. I then gradually reduced the amount of sugar, and now I don't need any. So, I suggest you initially mix just a bit of veggies with something you like, then gradually change the ratio until it's mostly veggies. StuRat (talk) 17:30, 8 February 2016 (UTC)

Incidentally, I notice that our OP recently asked a question about eating fruit that suggests that (s)he doesn't eat that either. That's a more worrying thing. SteveBaker (talk) 17:41, 8 February 2016 (UTC)

Falling from a building

If someone fell from the fifth floor of a building, would they die or just be badly hurt? 2607:FB90:1225:2047:A4E6:5421:24F2:7B82 (talk) 03:49, 8 February 2016 (UTC)

It depends how they land and what they land on. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:59, 8 February 2016 (UTC)

If they land on concrete? 2607:FB90:1225:2047:A4E6:5421:24F2:7B82 (talk) 04:12, 8 February 2016 (UTC)

Then it depends on how they land. But their odds are not good. Here is someone's idea for a strategy. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:16, 8 February 2016 (UTC)

It would be far better to land on a Life net. That's a little article I wrote a few years ago. Cullen³²⁸ Let's discuss it 04:20, 8 February 2016 (UTC)

Obviously. But the OP specified concrete. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:02, 8 February 2016 (UTC)

On page 17 of this OSHA document [28], figure 6 shows the distribution of workplace fatalities as a function of number of feet fallen. From that, you can see that a small number of people died after falls of less than six feet - and most people in the workplace who die after falling, fell less than 40 feet...which is less than 5 floors. So for sure, lots of people die every year from falling fell from considerably less height than the 5th floor.

A few other sources I checked with suggest the the risk of death starts to go up sharply at falls of around 8 to 10 meters - with about a 50/50 chance of dying if you fall from 15 meters and a near certainty of dying at around 25 meters. A typical building floor height is about 3.5 meters - so 5 floors would be 17.5 meters - and that's about a 75% chance of death. But there really is no 'safe' fall height. People trip and fall and whack their heads against something as they reach ground level and die as a result - so even a fall from zero height can be fatal.

CONCLUSION: If you fall from the 5th floor - you have roughly a 3 in 4 chance of dying - there is no 'safe' distance.

SteveBaker (talk) 04:59, 8 February 2016 (UTC)

Would it be a quick death or a long and agonizing one? 2607:FB90:1225:2047:A4E6:5421:24F2:7B82 (talk) 15:13, 8 February 2016 (UTC)

I don't see any data on that. One would presume that a head-first impact would be quick - and feet-first much less so - but it's very hard to say, and as skydivers soon discover, bodies rotate during free-fall in ways that can be hard to control. I wouldn't want to make any bets on that one. SteveBaker (talk) 17:07, 8 February 2016 (UTC)

Quick, call the Mythbusters before they're cancelled! FrameDrag (talk) 20:48, 8 February 2016 (UTC)

Is it best for a man/woman to see a male/female psychiatrist respectively?

Just curious if it's generally best for a man to see a male or female psychiatrist and for a woman to see a male or female psychiatrist, or if there's no recommendation in the psychology community. 2.103.13.244 (talk) 05:22, 8 February 2016 (UTC)

Most psychiatrists base their treatment on pills. I hardly see how it could matter the gender of those who prescribes you pills. Psychiatrists are also not necessarily part of the psychology community, they could be psychotherapists too, but primarily they are physicians. I suppose you want to know whether gender of psychologists, psychotherapists, counsels and the like matter.

On the practice it's clear that psychiatrists are mostly male, and the psychology community is mostly female. That reduces your chances of picking a specific gender. Anyway, the role of gender in the quality of psychotherapy seems to be negligible, in the same way that you don't need a therapist with the same age, religion, race, as you. I see that it could even be an advantage to have a certain distance from your therapist, since you both are not supposed to enter a private relationship. --Llaanngg (talk) 11:35, 8 February 2016 (UTC)

for a lot of this, perhaps most importantly on the first sentences of each paragraph. SemanticMantis (talk) 15:30, 8 February 2016 (UTC)

For some people, maybe. A psychiatrist is indeed different than a psychologist, but gender match in medical and therapeutic professions can indeed be a factor in outcomes. Here is a study that specifically looks at effects of gender matching in adolescents [29]. That one is freely accessible, these two studies [30] [31] are not, but they also discuss gender matching in therapeutic contexts. Note that all three also discuss matching of ethnicities as a potential important factor too. SemanticMantis (talk) 15:30, 8 February 2016 (UTC)

Having been treated by half a dozen psychiatrists and therapists, I will say that the race/culture, age and gender of your treatment providers definitely matters in some cases, even for "pill prescribers" because your story may sound different to different doctors. For example, I've been routinely noted to have "poor eye contact" and be diagnosed with borderline personality disorder and bipolar disorder by old white men, but younger psychiatrists are more up to date on neuroscience research and my female psychiatrists (including a South Asian) tend to agree with post-traumatic stress disorder or complex PTSD. Also Asian treatment providers definitely get cross-cultural struggles and Asian cultural values like conflict aversion, whereas white providers often don't, frequently chalking it up to some personality defect or saying that you're "non-assertive". Yanping Nora Soong (talk) 16:06, 8 February 2016 (UTC)

cramps or a "charley horse" after orgasm

My girlfriend often has serious cramps (or a charley horse)after she has an orgasm. The cramp is usually in her lower left calf. This is not a medical question. I am just curious how an orgasm and a cramp in the lower leg can be connected (given the very different muscles involved). 147.194.17.249 (talk) 05:41, 8 February 2016 (UTC)

For bemused readers.... Charley horse. Ghmyrtle (talk) 08:49, 8 February 2016 (UTC)

Orgasm often involves muscular contractions not just in the groin area, but throughout the body -- so in some cases, different muscles can cramp after orgasm. (I know first-hand, I've pulled a leg muscle once or twice during sex.) FWIW 2601:646:8E01:9089:14B5:216D:30B1:F92 (talk) 08:42, 8 February 2016 (UTC)

Differ love and porn! Porn can be violent. In some cultures sex is a secret and porn is the only “manual” and not a good advice at all. We have wikipedia and it sould give some more reliable information. The next step is You to care what You are doing. But some human are very fragile. When the charley horse is always on the same place You can find the reason. --Hans Haase (有问题吗) 11:37, 8 February 2016

(UTC)

Does Hans Haase 有问题吗's post above make sense to someone? In this case and in previous cases too I am unable to even guess what he's trying to say. --Llaanngg (talk) 11:45, 8 February 2016 (UTC)

Yes, I get the basic gist of it, and I usually can with Hans' posts. Then again, I have lots of experience reading listening to ESL. Respectfully, this is not the best place for such comments and discussion. SemanticMantis (talk) 15:19, 8 February 2016 (UTC)

Our articles on this are really, really bad. Charley horse confounds multiple conditions and multiple colloquial terms until there's no telling what is what. Cramp does virtually the same - it is hard for me to accept that the usual sort of "charley horse" has anything to do with failure of ATP to loosen muscles, since generally it is a sudden onset of a muscle contraction. We'll have to look this one up from scratch... after which, we might want to rewrite those articles quite nearly from scratch. Wnt (talk) 12:06, 8 February 2016 (UTC)

I should share the first good reference I found at [32] (I just did a PubMed search for leg cramp and this was one of the first things) Apparently there is a treatment for leg cramps ...... it involves injecting 5 ml of 1% lidocaine into the "bifurcation of the branches that is located in the distal two-thirds of the interspace between the first and second metatarsals" - this is a nerve block of "the medial branch, which is the distal sensory nerve of the deep peroneal nerve". The site is on the inside of the base of the big toe. The effect was to reduce cramps by 75% over a two-week study period. As part of their discussion they say

The mechanism(s) of leg cramps are yet to be clarified, but disturbances in the central and peripheral nervous system and skeletal muscle could be involved (Jansen et al. 1990; Jansen et al. 1999; Miller and Layzer 2005). Electrophysiologically, cramps are characterized by repetitive firing of motor unit action potentials at rates of up to 150 per sec. This is more than four times the usual rate in maximum voluntary contraction (Bellemare et al. 1983; Jansen et al. 1990). In a human study, Ross and Thomas indicated a positive-feedback loop between peripheral afferents and alpha motor neurons, and that this loop is mediated by changes in presynaptic input. This loop is considered a possible mechanism underlying the generation of muscle cramps (Ross and Thomas 1995). The frequency of nocturnal leg cramps has also been suggested to result from changes in hydrostatic pressure and ionic shift across the cell membrane in the calf muscles in the recumbent position, inducing hyperexcitability of the motor neurons. Consequently, the pain of the cramps may be caused by an accumulation of metabolites and focal ischemia (Miller and Layzer 2005). The difference in these conditions in each patient may explain the diverse symptomatology of the cramps.

So the thing I'm thinking of is possibly, not certainly, related to some kind of feedback, possibly via the spine only, between sensation of what the body part is doing and a motor response. It seems easy to picture how infrequent activities might somehow jiggle such a sensitive mechanism. Honestly, because this is a regulated phenomenon with different characteristics than usual contraction, I'm not even entirely sure it is pathological - for all I know, the body might be administering it as some sort of health intervention on itself. Note that I definitely cannot and will not diagnose the woman involved here - there are a thousand things she could be experiencing that aren't what I have in mind. Wnt (talk) 12:25, 8 February 2016 (UTC)

Have the OP and his girlfriend tried different positions? Seriously: I myself often used to (and still occasionally do) get leg cramps when sitting on a hard chair for extended periods – this first arose during long services in a cramped (heh!) school chapel – but avoiding such a position makes them much rarer. It may be that different postures during the act might change the forces on the relevant muscles sufficiently to lessen the problem. {The poster formerly known as 87.81.230.195} 185.74.232.130 (talk) 15:19, 8 February 2016 (UTC)

Jump cushion

Are jump cushions ever used in firefighting in lieu of life nets? If so, how effective are they? Do they even actually exist, given that they're not on Wikipedia? 2601:646:8E01:9089:14B5:216D:30B1:F92 (talk) 10:31, 8 February 2016 (UTC)

See [33]. Quoted maximum jump height is 40m. AllBestFaith (talk) 10:49, 8 February 2016 (UTC)

Thanks! 2601:646:8E01:9089:14B5:216D:30B1:F92 (talk) 05:57, 9 February 2016 (UTC)

How many defecators?

Is it possible to come up with a reasonable estimate of how many humans are defecating at any given moment? -- Jack of Oz ^{[pleasantries]} 11:56, 8 February 2016 (UTC)

If I were to pull a number out of my ass...50 million. Make a ballpark assumption the average human spends 10 minutes a day pooping, seven billion humans, and there you go. Should be within an order of magnitude of reality. Someguy1221 (talk) 11:59, 8 February 2016 (UTC)

Given that there are certain times when defecation is more likely (when you get up in the morning, and perhaps also before bed in the evening), the number doing it at any given time may depend on the population density of the time zones matching those times of day. First thing in the morning in China is likely to see a lot more poopers than the similar time in the mid-Pacific. — Preceding unsigned comment added by 81.131.178.47 (talk) 14:37, 8 February 2016 (UTC)

Today's SMBC comic [34] is highly relevant to this question [35] . SemanticMantis (talk) 18:29, 8 February 2016 (UTC)

Perspective machines

What's a perspective machine, or in particular, a railroad perspective machine? The main source for Nester House (Troy, Indiana) says "The building's 1863 design is attributed to J. J. Bengle, the inventor of the railroad perspective machine." Google returns no relevant results for <perspective machine>, and the sole result for <"railroad perspective machine"> is this main source. Nyttend (talk) 15:46, 8 February 2016 (UTC)

I haven't the foggiest but my guess would be that he invented a machine that helped with making accurate perspective drawings. Architectural drawings showing a building from an angle are normally axonometric projections where parallel lines stay parallel rather than using perspective. A nice perspective drawing helps with selling a design to a client. Dmcq (talk) 16:20, 8 February 2016 (UTC)

Just had a look around and machine like what I was thinking of, the 'perspectograph plotter', was made in 1752 by Johann Heinrich Lambert, see [36], which is before that man's time. So it was either something else or a refinement on that. Dmcq (talk) 16:39, 8 February 2016 (UTC)

There are several kinds of quasi-realistic perspective - "single point" and "two point" being the most commonly mentioned. I wonder whether the term "railroad perspective" might refer to single-point perspective - implying that the way that two parallel railroad rails seem to meet at the horizon. This is just a guess though...take it with a pinch of salt! SteveBaker (talk) 17:04, 8 February 2016 (UTC)

Yes, long parallel straight lines are relatively rare in nature, and in that time frame railroad rails would have been an ideal application for a perspective drawing. StuRat (talk) 17:22, 8 February 2016 (UTC)

My thoughts exactly. Thinking about a railroad "perspective-machine" didn't get me very far - but thinking in terms of a "railroad-perspective" machine definitely makes me suspect that we're thinking in terms of a single-point projection. Our article on Perspective mentions the word "railroad" three times when discussing this - so I'm starting to believe that this must be what's meant here. SteveBaker (talk) 17:31, 8 February 2016 (UTC)

Typeset content describing the building in the cited PDF says "railroad perspective machine" and "Bengle", but the hand-written inscription on the drawing of the building says "railway perspective machine" and spells the name "Begle" (no "n" in it). Googling for "railway pespective" finds tons of hits for the same one-point perspective that SteveBaker suspected. I'm not finding anything in Google's patent database for Begle though ("perspective" is a poor search term, since damn near every object patent includes a perspective drawing of it). DMacks (talk) 20:29, 8 February 2016 (UTC)

This newspaper article confirms that a "J. J. Bengle" lived in Denison, TX in 1907. I don't know how that ties in with any other known dates and places of residence of the architect. The newspaper article does not give any helpful details - "J. J. Bengle has returned from a trip to Galveston and other points." That's it in its entirety, I'm afraid. Tevildo (talk) 21:01, 8 February 2016 (UTC)

When my father was employed by the State Railways many years ago, as an Inspector of Permanent Way, he showed me a device he used which I recall was called a "perspective sight". It was essentially a modified pair of binocculars. It is critical that ralway lines be accurately parallel and straight, but get out of true over time for various reasons. Bad weather (washouts from exceptionally heavy rain) and extremely hot days can cause the lines to buckle. If you look with the naked eye, you cannot see buckling that will derail a speeding train. Binocculars foreshorten perspective, so if you stand between the two railway lines and look along the track with binocculars, you see the distance reduced, and because of the binoccular's magnification, any buckling becomes easily visible. The binocculars the Railway supplied (the "perspective sight") had an adjustable pair of lines that converge on a point (the vanishing point). You adjusted the lines so that they aligned with the railway lines - giving a minor advantage in seeing any buckling. There were horizontal calibation marks (which have non-linear spacing due to viewing height & perspective) so that the inspector could say to the maintenance crew things like "go forward 320 metres and straighten there." They had a special instrumented carriage for detecting rail missalignment, but the binocculars facilitated a quick response to any problem due to extreme weather, regardless of where the instrument carriage was. 1.122.229.42 (talk) 00:53, 9 February 2016 (UTC)

• As a matter of curiosity, what country's "State Railways" did he work for? --76.69.45.64 (talk) 05:13, 9 February 2016 (UTC)

Excellent info ! StuRat (talk) 00:58, 9 February 2016 (UTC)

Wow! That's a typically ingenious invention for the era. Sadly, these days a couple of visible light laser beams would make a much simpler and more efficient solution. I wonder how they coped with warping around curves and across varying slope though. SteveBaker (talk) 03:38, 9 February 2016 (UTC)

Technology for the disabled

What is the current status for:

1. Body part less people.
2. Blind sighted people. exclude surgery.

Are there any satisfactory mechanisms out there to grant capability?

Apostle (talk) 18:31, 8 February 2016 (UTC)

Fixed title to be proper English. StuRat (talk) 18:33, 8 February 2016 (UTC)

-- Apostle (talk) 22:36, 8 February 2016 (UTC)

1) I assume you mean people missing body parts. See prosthetics.

2) I don't think most causes of blindness can be addressed without surgery, assuming implanting electrodes into the brain is considered to be surgery. I think there was some research on attaching a grid of electrodes (with just tape) on the back, and using those to convey visual images, so that might qualify. StuRat (talk) 18:35, 8 February 2016 (UTC)

There is an enormous amount of technology for the blind - from talking clocks to software able to scan a printed document and turn it into artificial speech. — Preceding unsigned comment added by 81.131.178.47 (talk) 18:56, 8 February 2016 (UTC)

Some blind people use a device that helps them to "see" using their tongues [37] [38]. SemanticMantis (talk) 21:16, 8 February 2016 (UTC)

I'll go through the links... Thank you -- Apostle (talk) 22:36, 8 February 2016 (UTC)

And about number 2): BBC was showing a program where this blind woman was viewing throw her eyes (black & white) fuzzily. The mechanisms they implanted inside her eyes are apparently compulsory to repair every 6 months. There was also a electrical box, her brain was probably connected... - can't recall properly.

The technology was very depressing; knowing that its the 21st century (or something). -- Apostle (talk) 22:36, 8 February 2016 (UTC)

See visual prosthesis for this particular type of device. Tevildo (talk) 23:10, 8 February 2016 (UTC)

The technology to interface nerve fibers to electronics is extraordinarily difficult. It's not like there is a red wire labelled "Video In" in the interface between eyes and brain - instead there is a large bundle of unlabelled nerves - all different from one person to another. It's not like each nerve is a "pixel" or anything useful like that. Maybe one of them says "There is a high contrast, vertical line, about a quarter the height of the retina that's moving left to right" - figuring out what to say to each nerve from a camera is beyond what we can currently do...we can try to rely on brain plasticity to cope with whatever incorrect data we're sending - but that's how you end up with fuzzy, low-resolution monochrome - and experimental devices that don't survive long-term implantation. Also there are at least a dozen reasons why someone might be blind - and each one needs a separate, and equally difficult solution. This is an exceedingly difficult problem and it may be decades before we have something that truly works and is actually useful to people. SteveBaker (talk) 03:34, 9 February 2016 (UTC)

Accelerating a particle with light

If I accelerate a tiny speck of dust using light, what max speed could be it reach? Let's suppose that hypothetically we can know exactly where this speck of dust is, and that we know how to point a laser at it. --Scicurious (talk) 19:22, 8 February 2016 (UTC)

Theoretically you could accelerate it to almost the speed of light. StuRat (talk) 19:24, 8 February 2016 (UTC)

Assuming you find a void in space that (with much luck) presents no molecule of gas to hinder the speck's progress, there is still microwave background radiation defining an approximate cosmic rest frame, which would become blue-shifted as the particle approaches it as the light source you use becomes red-shifted - also starlight of course, which is similarly in a fairly consistent rest frame all around. As a result, if you assume a constant light intensity in a perfectly focused beam, I think there would be a maximum level that you can use at the beginning to avoid vaporizing the particle, which eventually becomes weaker than the oncoming radiation. On the other hand, if you continue to turn up your light source (or increase its frequency) then I suppose the particle might accelerate without limit, coming arbitrarily close to light speed. Unless, of course, I forgot something else... Wnt (talk) 19:52, 8 February 2016 (UTC)

Isn't this how solar sails work? Nyttend (talk) 21:10, 8 February 2016 (UTC)

Immunity vs resistance

Is there a difference, and if so, what is it? Are they the same but used for different species, or is there a clear but subtle difference? In other words, does "She is immune to the flu" mean the same as "She is resistant to the flu"? What about "This strain is resistant to drug X" and "This strain is immune to drug X"? 140.254.77.216 (talk) 19:51, 8 February 2016 (UTC)

"Immune" means 100%, unless some qualifier is added like "partially immune". "Resistance" is less than 100%. StuRat (talk) 19:54, 8 February 2016 (UTC)

The problem here is that you are using a literary definition of immune, StuRat, and that while I agree with you in that way, SemanticMantis and the heretical Wnt much more closely approach the received biological notion. In the school where I got my undergrad biology major (focusing in botany), you had to have four years of chemistry and four years of bio-major "bio" before you could even apply to take Immunology 396. So I would take their comments as read. μηδείς (talk) 02:47, 9 February 2016 (UTC)

You know, I can see how you'd think that. The problem is that your explanation is completely incorrect in terms of medical and physiological terminology. Immunity_(medical) discusses how the term is used. An easy example sentence "All vaccines confer immunity, but not all vaccines are 100% effective, and so some people who have acquired immunity from a vaccine may still get infected." My dictionary says "Immune: resistant to a particular infection or toxin..." Wiktionary says "Protected by inoculation", Miriam Webster says "having a high degree of resistance to a disease <immune to diphtheria>". The only time immune means 100% resistance is in fiction, games, or legal matters. SemanticMantis (talk) 21:28, 8 February 2016 (UTC)

Active immunity represents a process of natural selection within immune cells of the body (cell mediated immunity or antibody mediated immunity) by which molecules become common that (in some context) interact with a pathogen and allow it to be destroyed. In drug resistance, bacteria produce molecules that neutralize a drug, frequently by enzymatic means, often using plasmids to allow trading of useful resistances within a broader genetic background. So the selection for immunity takes place within an organism, but the selection for resistance occurs between organisms - most bacteria die, a few live and become resistant. So to be "resistant" to something is more of an inborn trait, generally speaking, while "immunity" usually implies past exposure to the agent or a vaccine etc. Exception, sort of: multidrug resistance in cancer occurs within an organism. But if you look at it another way, every cancer cell is out for itself, and (apart from the one that mutates) is either born resistant or not. Another exception, sort of: innate immunity may not require a selective response; the thing is, we rarely hear that someone is innately immune to a pathogen because they never know they might have gotten sick. This reminds me, say, of toxoplasmosis which preferentially affects those of the B cell type. (There was actually a huge outbreak in postwar Japan, and Japanese became known for "blood type personality theory", to this day never having been aware of the role of the protozoan in affecting their minds...) Wnt (talk) 20:05, 8 February 2016 (UTC)

February 9