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July 7

Meaning of "angles of the jaw" (and a source if possible)

Hey all. I am currently working on an article under featured review: Glossary of bird terms. A poster at this section of the featured review has asked about the article's definition for a birds gular region, which I defined in the article by quoting a source, as:

The posterior part of the underside of a bird's head, described as "a continuation of the chin to an imaginary line drawn between the angles of the jaw".^[footnote]

If you read the discussion, I have crapped out on finding a source for what "angles of the jaw" means. I have postulated what I think it means but I'm not sure I'm correct. All the source I've found (not necessarily bird related) use it without defining it. Can anyone dig up a source, maybe from JAMA or something, that defines the expression? Anyone sure of the meaning? Thanks in advance--Fuhghettaboutit (talk) 01:10, 7 July 2017 (UTC)

Is it possibly a place corresponding to the Angle of the mandible...? --CiaPan (talk) 10:07, 7 July 2017 (UTC)

Oh, I forgot to ping. Here it is: Fuhghettaboutit. --CiaPan (talk) 10:08, 7 July 2017 (UTC)

• There is also something called a gonydeal angle mentioned in Beak#Gonys section. However, my knowledge in ornithology and general anatomy, and even English language, is not sufficient to let me guess if it has anything to do with angles you seek. --CiaPan (talk) 10:17, 7 July 2017 (UTC)

Aha, angles of the mandible! Well done CiaPan. I will link that to the term. Glad to see my guess as to what it is was on target.--Fuhghettaboutit (talk) 11:48, 7 July 2017 (UTC)

Exercise

Please list some exercising movements for warm-up, stretching and building the whole body (bit by bit and or as well as in whole) without using any exercising tools. Name with Illustrations of the move(ment)s desired. 103.67.156.122 (talk) 14:45, 7 July 2017 (UTC)

See Calisthenics. Loraof (talk) 16:40, 7 July 2017 (UTC)

See also Dynamic Tension --TrogWoolley (talk) 16:53, 7 July 2017 (UTC)

Starting to do the exercise (e.g. running) itself is good enough. The idea that you need to do a warm-up before exercising has been debunked by rigorous scientific studies. There is no relation between injuries and doing a warm-up, not even for sports where you burden your muscles heavily like body building. While authoritative sources claim otherwise and continue to say that warm-up is recommended to prevent injuries, these statements are not based on scientific evidence in the form of statistically significant more injuries when people don't do the recommended warm-up exercises. Note that Jack LaLanne never did warm-ups, he once said ""15 minutes to warm up? Does a lion warm up when he's hungry? 'Uh oh, here comes an antelope. Better warm up.' No! He just goes out there and eats the sucker."" Count Iblis (talk) 20:38, 7 July 2017 (UTC)

From our article Warming up—mixed results, with citations:

The risks and benefits of combining stretching with warming up are dispute, although it is generally believed that warming up prepares the athlete both mentally and physically. In a meta-study of 32 high quality studies, about 4/5 ths of the studies showed improvements in performance.[1] Warm-up programs can improve the strength of the knee muscle, which, in turn, may decrease injuries.[2] A comprehensive warm-up program did not significantly decrease injuries in football compared to a control group.[3] -Loraof (talk) 21:02, 7 July 2017 (UTC)

It's stretching–especially static stretching–before exercise that has been found to be worse than useless. Warming up (without overstretching) is just a sort of exercise, n'est–ce pas? Abductive (reasoning) 03:38, 8 July 2017 (UTC)

One of the most practiced worldwide (250 million [1]) and thus most successful seems to be chinese Tai chi. --Kharon (talk) 07:27, 8 July 2017 (UTC)

Modern torpedoes aren't design to hit a ship?

I read somewhere that, "many modern torpedoes aren't designed to strike a ship, but instead explode directly underneath it. The shockwave in the water will move so much water away from the ship that it will literally bend and break under its own weight." Is this true? ScienceApe (talk) 17:41, 7 July 2017 (UTC)

Where did you read it? ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:48, 7 July 2017 (UTC)

Choosing a random article for a modern torpedo, Spearfish torpedo, I find the phrase "A standoff detonation under the keel enhances blast effects against surface ships through the amplification of stress resulting from the interaction of the explosion's products and the flexible structure of the ship.". Unfortunately, it's not referenced, except to an impressive youtube video of a test firing. ApLundell (talk) 18:06, 7 July 2017 (UTC)

There are many references: [2] [3] [4] [5] ... It shouldn't take long to find one that is considered "reliable." 209.149.113.5 (talk) 19:43, 7 July 2017 (UTC)

We have an article proximity fuse. Sagittarian Milky Way (talk) 21:17, 7 July 2017 (UTC)

• It has been a goal since before WWII. It was mostly needed during WWII, because the prime target of the day, a capital ship, would typically have a torpedo bulge. This is a form of spaced armour around the waterline. The easiest way to defeat it was thought to be by exploding beneath the ship.

The difficulty was in how to control the depth of the torpedo, and how to fuze it to explode beneath. US submarine-launched torpedoes at the start of WWII were particularly bad for this. The Mark 14 torpedo couldn't reliably control its depth, its Mark 6 exploder had problems both with magnetic detection when running beneath the ship, or its contact pistol when it had a direct impact. Andy Dingley (talk) 21:25, 7 July 2017 (UTC)

As for a reference try: Torpedo: The Complete History of the World's Most Revolutionary Naval Weapon (p. 157) by Roger Branfill-Cook, in a section headed "Explosions beneath the keel". This explains the physics behind it, but also says that it will be less effective against ships larger than a modern frigate or WWII destroyer. Contact torpedoes were used by the commander of HMS Conqueror (S48) in his successful attack on the large cruiser ARA General Belgrano in 1982; however the usual line is that the more modern Tigerfish homing torpedoes that he also had available were of doubtful reliability. Alansplodge (talk) 22:25, 7 July 2017 (UTC)

The history of the Fishfart and Stingwhelk torpedoes, and their unreliability, is left as an exercise for the reader in 1980s UK defence procurement. Andy Dingley (talk) 23:10, 7 July 2017 (UTC)

For Andy's second humorous reference, see Stingray torpedo which had to be totally redesigned just as development was nearly complete. Unlike the Tigerfish, it was made to work in the end. Alansplodge (talk) 08:40, 8 July 2017 (UTC)

Steve Bell's If... Andy Dingley (talk) 09:22, 8 July 2017 (UTC)

I have added the Branfill-Cook ref to the Spearfish article and using the same ref, have added two paragraphs to Torpedo#Warhead and fuzing. Alansplodge (talk) 17:48, 8 July 2017 (UTC)

Dog regurgitating tater tots

In this short nature documentary a dog is seen to regurgitate small food morsels in a form which appears they did not enter the stomach. Most don't seem to have lost their integrity and they appear largely dry. Could these have been anywhere between the mouth and the stomach? Could the dog have been expecting to be called out and was prepared to have to regurgitate? — Preceding unsigned comment added by 145.255.245.88 (talk) 18:04, 7 July 2017 (UTC)

They were obviously in the mouth. Ruslik_Zero 20:45, 7 July 2017 (UTC)

So you reckon the dog retained them in its mouth to determine whether their loss would be noticed before eating? I can't think of any other explanation. Maybe one has to think like a dog. --145.255.245.88 (talk) 00:09, 8 July 2017 (UTC)

It could well be that it's a trick. Not that I think it's impossible for a dog to do this on its own initiative; they very often carry things around in their mouths before ultimately deciding to eat them. Still, something feels a bit artificial about the video. In any event, it's certain that dog did not regurgitate those items. Dogs strain quite noticeably (and audibly) during the act of regurgitation (and even more so for vomiting). Plus, as you pointed out in your initial comments, the integrity of those tots would not have been as it was, had the dog ingested the tots--but that's true even if the tots had been consumed even a little, aside from being held in the oral cavity momentarily. This doggy got a taste, but very little satisfaction--unless the motive had more to do with attention than appetite! Snow ^{let's rap} 01:34, 8 July 2017 (UTC)

In thinking like a dog, remember to take account of their physical differences. Dogs don't have hands (though I suspect cats are secretly working on it) so naturally use their mouths to carry things they don't necessarily intend to eat, at least not immediately. {The poster formerly known as 87.81.230.195} 90.211.129.9 (talk) 08:17, 8 July 2017 (UTC)

July 8

Is that true that things which plugged in consume electricity while they don't work?

I've been told that things that are plugged in, consume electricity even while they don't work. For example kettle, oven, or even just a phone charger which plugged in, while it's without the phone. Is that true? If it is, then for me it doesn't make sense and I would like to know the explanation behind it. 5.102.253.81 (talk) 03:05, 8 July 2017 (UTC)

Many electronic devices such as televisions, do draw a trickle of current to maintain readiness when switched on. But 'dumb' devices such as toasters, electric ovens and so forth generally don't. You can buy a current tester at the hardware store to check how much electricity is flowing when a device is nominally 'off' if you worry about these things. Abductive (reasoning) 03:34, 8 July 2017 (UTC)

See our standby power article for more information. DMacks (talk) 03:35, 8 July 2017 (UTC)

And such "vampire" devices which use standby mode are an increasingly large proportion of all consumer electronics. Unless all current is cut to the device or a diagnostic forces a restart, most such items never de-power their built-in computers--which were traditionally very simple but which now have increasingly complicated tasks, not the least of which today is networking with other devices and (increasingly), the internet of things. Most consumer electronics are moving towards a design where they are almost never completely "off", nor even off in a significant sense. Many still give an impression that something drastic changes when you hit the power button, but the reality is that the difference between being "on" and being in "standby mode" for some devices is no more significant than the status of the indicator lights on the device's exterior: the device is still communicating with other devices and/or a network or even an internet connection, and is just as prepared to do what it is designed to do as it would be at any other time. Still, for larger appliances, these standby functions of the computer and antennae are likely to represent a small amount of power consumption compared to the energy utilized when the appliance is performing it's nominal function. Even so, there are concerns about the aggregate amount of extra power that is being utilized (and arguably wasted in many cases) by vampire electronics as they become more and more prevalent. Snow ^{let's rap} 18:23, 8 July 2017 (UTC)

'dumb' devices such as ... electric ovens .. generally don't. — Very old electric ovens don't, but I suspect that any electric oven built in the last few decades includes an electric clock, which always draws some current. Mitch Ames (talk) 12:42, 8 July 2017 (UTC)

And very soon, I doubt there will be an oven built for mass manufacture anywhere in the world that doesn't have a (relatively) sophisticated computer. I imagine an oven is one of those devices that manufacturers will begin to add network capabilities to last, because of liability concerns (the idea that an oven can be turned on remotely, and thus be susceptible to hacking or command errors must be a concern for even those companies which are moving aggressively on making their devices network enabled by default), but (at least when in the first world) I have rarely seen an oven in the last decade that does not have some degree of programmable function. Snow ^{let's rap} 18:36, 8 July 2017 (UTC)

(ec)To use electricity there has to be a completed circuit. Any appliance with something going on while powered off, such as a clock, will consume electricity. More details are in Standby power. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:36, 8 July 2017 (UTC)

Charging devices often draw some current even when nothing is connected to them. This happens because they contain transformers, which allow for a completed circuit on the input side even if there is not a completed circuit on the output side. However the null current is usually very small, in the milliwatt range. Looie496 (talk) 14:41, 8 July 2017 (UTC)

... and the same applies to modern switch-mode power supplies used for charging. Dbfirs 16:11, 8 July 2017 (UTC)

Plugging in even an appliance with its mains switch at OFF causes a small AC current to flow in the capacitance between its power conductors. This happens throughout the cables of a network and AC generators experience a significant capacitive load when driving long distribution lines. However this reactive current leads the voltage cycle by 90 degrees and therefore does not contribute to the measured "true" AC power consumption given by P=VI cos φ, see Wattmeter. An electricity supplier charges only for true power consuption but could in principle detect whenever you plug in an appliance by time-domain reflectometry. An advantage of a DC distribution system over AC is that there is no continuous current in cable capacitance, only a one-time inrush at start-up. Blooteuth (talk) 18:01, 8 July 2017 (UTC)

One rule-of-thumb is that if the plugged-in device gets hot, or even warm, when not in use, then it's using lots of electricity. The temperature is measured relative to the surroundings. StuRat (talk) 18:15, 8 July 2017 (UTC)

If humans never cut their hair, then will the hair insulate the body like fur?

Non-human animals don't wear clothes. Mammals may have fur to keep warm. If humans never cut their hair, then will the hair insulate body heat and cover the genitals? In other words, can long hair do away with the need to wear clothes? Also, I remember watching a King Kong movie and Jumanji, and I noticed the bearded men just shaved off their beard. What's the deal? Why do humans shave off their hair? 50.4.236.254 (talk) 04:04, 8 July 2017 (UTC)

1) No, human hair is just too thin to provide insulation anything near what clothes can provide. We don't have polar bear hair.

2) Shaving a beard may make hygiene easier (no food collecting in the beard) and make emotions more obvious if smiling and frowning weren't visible before. It also can make the man cooler in summer and avoid icicles forming in it in winter. Then there's just style and cultural or personal preference. StuRat (talk) 05:30, 8 July 2017 (UTC)

Did you actually bother to read Body hair or Beard before coming here, 50.4.236.254? {The poster formerly known as 87.81.230.195} 90.211.129.9 (talk) 05:40, 8 July 2017 (UTC)

It does not talk about fur. It does mention furry mammals, but still, humans today still have hair. It may not be as numerous as before, but it's not labeled as fur. 50.4.236.254 (talk) 11:48, 8 July 2017 (UTC)

Humans don't have fur. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:17, 8 July 2017 (UTC)

A thick head of hair does provide a bit of protection against cold or against sunburns of the scalp, although not substantially... As for the rest of body hair, it's less effective than the adipose/fat tissue under the skin. —PaleoNeonate - 12:50, 8 July 2017 (UTC)

Does this mean that humans with more adipose tissue have an easier time staying warm during the winter but harder time staying cool during the summer than humans with more muscle mass than fat mass? 50.4.236.254 (talk) 14:10, 8 July 2017 (UTC)

They said hair provided some protection from sunburn so there is no implication that way in what has been said. Please read adipose tissue which discusses adipose/fat tissue further. Dmcq (talk) 14:58, 8 July 2017 (UTC)

PaleoNeonate did also say "As for the rest of body hair, it's less effective than the adipose/fat tissue under the skin" so they did raise adipose/fat tissue insulation issues although didn't imply insulation works the way the IP seems to think it does. I agree the IP really needs to learn to read more rather than just asking whatever crap comes to their head, presuming they really aren't trolling which is getting harder and harder to believe. Nil Einne (talk) 15:36, 8 July 2017 (UTC)

What kind of questions do you expect or want to see? 50.4.236.254 (talk) 16:04, 8 July 2017 (UTC)

From you? Probably none would be the best solution. If you can't help it, at least put some basic thought and preferably reading/research before asking stuff like "Is there a governing body for astronauts? Are they excused from paying taxes? How are food resources used? Do they have families in space too?" Nil Einne (talk) 17:40, 8 July 2017 (UTC)

Long hair is nice but it doesn't extend indefinitely - there is a catagen cycle where hairs drop out, which usually doesn't let it get to storybook lengths. But we do have a picture in that article of a German model with some really long hair -- I don't know how she does it. Wnt (talk) 15:37, 8 July 2017 (UTC)

We should discuss some of the advantages of clothes over thick fur/hair. They allow us to select whatever clothes are appropriate for that day or even portion of the day, while fur/hair can't be changed nearly so quickly. So, while animals may have a summer coat and a winter coat, we can adjust our level of insulation based on the daily weather, can select waterproof or water-resistant clothing when rain is expected, and can clean or replace our clothing when it's dirty or damaged. Compare this to how a cat cleans it's fur with it's tongue, regularly resulting in hairballs, and you can see how much better clothing is. Also, fleas and ticks are more of a problem for animals with thick hair and fur. Sweating is more effective for cooling with bare skin, although some animals, such as horses, sweat with thick coats of hair. Military camouflage can also be changed quickly when it's in the form of clothes, versus hair or fur. Note that the most flexible camouflage in nature is from bare-skinned animals, such as cuttlefish and chameleons. There's also a range of special-purpose clothing, like a dry suit, chem suit, and astronaut's suit. StuRat (talk) 20:15, 8 July 2017 (UTC)

There is a myth among short-haired people that long hair is hot in the summer, but nothing could be further from the truth. The way hair lays allows an outer layer to take the brunt of the sunlight, while a lower layer wicks sweat from the body and stays cool. (In many other animals these layers are specialized, with guard hairs for the former function). Without hair, the sweat just drips off all over, a mostly useless waste of water. Wnt (talk) 10:05, 9 July 2017 (UTC)

Depends a bit on the type of hair. Afro-textured_hair#Evolution discusses how this is considered to be the type of hair all our ancestors had, and indeed provides a cooling effect. Various other types of hair developed in colder climates most likely have subtle differences in total insulation/air circulation effects. SemanticMantis (talk) 15:06, 9 July 2017 (UTC)

Digital audio: any advantage for whole number of cycles?

In digital audio, is there any advantage -- other than the computational optimization when synthesizing -- to using sound waves whose period is a whole number of samples (e.g. 441 Hz instead of A440 on a CD, since the sample rate is 44100 Hz)? I ask because 44100 is 2²3²5²7², which suggests a particular septimal tuning if the answer is yes. NeonMerlin 13:52, 8 July 2017 (UTC)

Theoretically there is no advantage —– the Nyquist–Shannon sampling theorem says that a sampling rate of 44100 Hz will perfectly capture any signal made up of frequency components below 22050 Hz. However if the program cuts corners in its signal processing algorithms, it is hard to rule out effects. Looie496 (talk) 14:32, 8 July 2017 (UTC)

A very simple monophonic tone Synthesizer for Electronic music is based on frequency dividers fed by a single oscillator. This allowed an early use of the speaker in the IBM Personal Computer to generate waveforms using the programmable interval timer. However division by whole numbers of clock cycles restricts the available frequencies so that Septimal tuning is possible but the conventional (in the West) Equal temperament tuning where successive note frequencies are in the ratio ¹²√2 ≈ 1.059463 can only be approximated. Modern digital music synthesizers use DSP techniques to calculate the amplitude of each sample in the time domain, and the stream of digital samples passes to a Digital-to-analog converter followed by a low-pass Reconstruction filter that removes the spurious effects of whatever finite sample frequency was used, see Whittaker–Shannon interpolation formula. Blooteuth (talk) 16:16, 8 July 2017 (UTC)

Lizard Identification

Looking to identify this lizard spotted on a tree in Home Depot parking lot in Stuart, FL. I suspect it is invasive / exotic pet. https://www.flickr.com/photos/somedumbaddress/35669273661/in/datetaken/ Thanks! — Preceding unsigned comment added by 2602:306:C4D5:DF60:FD57:922B:4DC7:DB82 (talk) 18:53, 8 July 2017 (UTC)

Looks like a Knight anole, which are native to Cuba but have been widely introduced to South Florida, which includes Stuart, Florida. StuRat (talk) 20:28, 8 July 2017 (UTC)

Yep, looks like that to me too. Certainly some type of anole, and the size and head shape do look like the Knight. SemanticMantis (talk) 15:02, 9 July 2017 (UTC)

Thanks, I think your ID is correct. I hadn't checked through the Anole family because I assumed they were all much smaller, like the more common Brown and Green Anoles. — Preceding unsigned comment added by 2602:306:C4D5:DF60:FD57:922B:4DC7:DB82 (talk) 17:13, 9 July 2017 (UTC)

Resolved

StuRat (talk) 18:59, 10 July 2017 (UTC)

July 9

Non-human neurobiology, memory cues, and episodic memory

For some reason, certain objects around me trigger a specific episodic memory. The house always reminds me of the time when I literally drew a picture of it with colored pencils. When traveling to a destination by car, my spatial memory allows me to find a specific location. Then, I remember how elephants can migrate and remember exact locations, provided that humans allow them to migrate beyond the borders of nature parks and countries. Could it be that episodic memory evolved because it enabled creatures to remember specific things, like a watering hole or abundant food source during a specific time of year, and to recognize patterns? 50.4.236.254 (talk) 02:23, 9 July 2017 (UTC)

Absolutely. The memory of "what did I do the last time I was in this situation and was it the best choice" is vital to survival, and thus passing down genes. Of course, other animals won't think of it in those terms, and may only recall fear when they encounter an animal that wounded them in an earlier encounter, and then back off from the confrontation because of that fear.

As far as experiments to show this, there's the ever popular mouse running a maze experiment. The more they do a particular maze, the more they remember of which way to turn at each intersection, etc., and the quicker they get to the food at the end. Then there's Ivan Pavlov's dogs, which learned to associate a bell with food.

Incidentally, this type of memory may take up lots of space, so animals with larger brains may have substantially more of it, perhaps more than humans. StuRat (talk) 02:28, 9 July 2017 (UTC)

Also interesting: you may remember smelling when winter or spring comes and being overwhelmed by pleasant memories. There are strong links between olfaction and memory (also more at Olfaction). Other animals also obviously rely much more on scent than we do. —PaleoNeonate - 14:29, 9 July 2017 (UTC)

Can a person distinguish Greenwich mean time and coordinated universal time when setting a clock manually?

A request for an argument by a known sockpuppet, rather a genuine question.
The following discussion has been closed. Please do not modify it.
This article Reaction time suggests that they can't. 81.131.180.213 (talk) 07:29, 9 July 2017 (UTC) Yes, because the difference is sometimes greater than the 200ms reaction time, and, with a bit of practice, I used to reduce the reaction time when setting my watch from the time signal to less than 100ms. I had to reset my accurate watch every time there was a leap second. I agree that most people are not that fussy about a fraction of a second, and most clockwork and quartz clocks cannot maintain the accuracy necessary. Devices that self-adjust from a GPS or long-wave time signal will certainly show a difference between mean solar time and Coordinated Universal Time. "GMT" can be used for either of these times, depending on context. Dbfirs 07:43, 9 July 2017 (UTC) This seems to be something of an oxymoron. Greenwich mean time has been around since 1840. Coordinated universal time has been around since 1960. The various scientific terms have precise meanings - if your claim that GMT can be used for UTC is correct one would expect that UTC can be used for GMT. Do you have a reliable source for your assertion? 81.131.180.213 (talk) 08:02, 9 July 2017 (UTC) UTC has a precise definition, unlike "GMT" which is used in two differing ways, though the difference is always less than a second and most people don't care about the difference. As timekeeping becomes more accurate, terms adjust their meaning, as stated in our article Greenwich mean time. I agree that for navigational purposes, GMT might retain its mean status. Dbfirs 12:26, 9 July 2017 (UTC) The claim that GMT "is used in two differing ways" did not appear in your answer as originally posted. Neither of your responses provides references, although all refdesk answers are supposed to include them. The only reference you've provided is a Wikipedia article, which is not a reliable source. Are your answers simply your own personal opinion (something which is not allowed on the refdesk)? "Terms adjust their meanings" is another oxymoron - the adjustment is done by people. Science being a precise discipline I find it rather far - fetched that scientists, having gone to the trouble of providing precise definitions for different timescales would then use the names indiscriminately. Back in the 1920s "Greenwich Mean Time" did have two meanings - the civil meaning of "mean solar time at the Greenwich meridian counted from midnight" and the scientific meaning of "mean solar time at the Greenwich meridian counted from noon". In 1925 the civil timescale and the scientific timescale became identical (measured from midnight) and the astronomers started using the snappier title "Universal time", something which did not catch on with the general population, who continued to call the timescale "Greenwich mean time". In 1960 the civil atomic timescale was given the name "coordinated" to distinguish it from the rotation - based "mean". Are you saying the convention has changed? 86.159.235.7 (talk) 16:22, 9 July 2017 (UTC) On the contrary, the reference desk is for directing enquirers to appropriate Wikipedia articles. I suspect that you are continuing an old argument, so I will not respond further. Dbfirs 20:24, 9 July 2017 (UTC) This is becoming rather murky. On 24 April 2015 the lead included the statement Coordinated Universal Time is kept within 0.9 seconds of GMT. The statement was referenced, and having read the book I can confirm that it is properly sourced. On that day Dbfirs added the unreferenced claim GMT is very close to Western European Time, and is often considered to be identical to Coordinated Universal Time in the UK. The same evening he added this referenced claim: GMT is now UT1 or UTC. The reference did not support the claim (it didn't mention coordinated universal time, as you can see)[6] so the "BRD" cycle continued with the changes being reverted and an explanation provided in the edit summary. The next step should have securing agreement on the talk page. Instead Jc3s5h decided to tag - team by starting an edit - war backed by another reference which was not easy to verify as no URL was provided. When it was checked it nowhere stated that Greenwich mean time is now identical to coordinated universal time, as claimed. To add insult to injury, he removed a reference dating from 2014 with the spurious edit summary claim that it was 39 year[s old]. On the talk page it was pointed out that Seago, Seidelmann and Allen [a source cited in the article] confirm that UT1 ... is a precise astronomical measure of the rotation of the Earth on its axis, synonymous with mean solar time at the meridian of Greenwich, sometimes known simply as Greenwich mean time (GMT). Dbfirs didn't respond but instead made the counter - claim that the British government "seems to think that GMT has been the same at [sic] UTC since 1972". Examination of the source [7] shows him using synthesis to push his POV. On 7 June 2015 the claim Today GMT is considered equivalent to UTC for UK civil purposes (but this is not formalized) was added, and the reference provided, when examined, was found not to mention Greenwich mean time at all. It appears that Dbfirs has some explaining to do - perhaps this is why he has disengaged from the discussion.

Rare events predicted by a "theory of everything"

For example, most grand unified theories predict proton decay with a very long half-life, something not predicted by the standard model. Are there any extremely rare events predicted by a theory of everything that are not predicted even by a GUT, let alone the standard model? Surprisingly, I can't seem to find an answer in our articles on theory of everything, string theory, or M-theory. PeterPresent (talk) 14:36, 9 July 2017 (UTC)

The "theory of everything" does not exist yet. --AboutFace 22 (talk) 17:55, 9 July 2017 (UTC)

https://arxiv.org/abs/hep-ph/0703221 Count Iblis (talk) 20:09, 9 July 2017 (UTC)

Thanks for that paper! So, according to that paper, a prediction of string theory is that the universe will transition into an "exactly supersymmetric" universe with different properties. Is this actually a novel prediction of string theory though? Aren't there GUTs or other theories (e.g. Minimal Supersymmetric Standard Model) that also predict this phenomenon? PeterPresent (talk) 01:50, 10 July 2017 (UTC)

I think that within string theory it's harder to get around the exact supersymmetric ground state than within effective field theories such as the Minimal Supersymmetric Standard Model where you can introduce all sorts of terms in the Lagrangian to change the predictions. Count Iblis (talk) 21:27, 10 July 2017 (UTC)

The biggest criticism of string theory / M-theory is that it hasn't offered any testable predictions that distinguish it from other theories. There are a few possibilities that aren't very testable. Some versions of M-theory allow for other "universes" parallel to our own but whose gravity can still affect our universe (and sometimes identified with dark matter). Finding evidence of that would be exciting, but you can also have M-theory without that element (or with other universes so distant as to be completely undetectable). Similarly, string theory allows for compact extra dimensions. Evidence of such extra dimensions could show up in particle accelerators, or the extra dimensions could be a billion billion times too small to be seen with current accelerators. So, if you find them, it would be good evidence, but not being able to find them proves nothing. String theories can also give rise to a wavelength-dependent variable speed of light and time-variation of fundamental constants, though neither concept is exclusive to these theories, nor are the effects required to be remotely large enough that humans are likely to be able to observe them any time soon. These theories sometimes also predict non-trivial internal structures for black holes (e.g. fuzzball (string theory) and might have implications for Hawking radiation, but it is unclear if those ideas are testable even in principle. Dragons flight (talk) 08:08, 10 July 2017 (UTC)

Sometimes, a theory can make a prediction that some extremely rare event may occur. For example, although most predictions of GUTs would in practice require experiments in the GUT scale, most GUTs predict that protons decay - something that could occur not at all in the GUT scale - but only very rarely. I'm interested in predictions like that. Does string theory / M-theory / TOE predict some extremely rare phenomenon - even on normal energy levels - that is not predicted by our current theories of even GUTs. PeterPresent (talk) 08:24, 10 July 2017 (UTC)

A theory of everything is needed to unite gravity with quantum mechanics, which is believed to be the last stage in connecting the various known forces in the universe. Pretty much any particle physics process imaginable, such as proton decay, can already be predicted in some GUT theory without the need for gravity. Where a TOE makes new predictions, to the extent that any of them do, is in areas like gravitation, dark matter, black holes, etc. I already gave you examples of those. Dragons flight (talk) 08:53, 10 July 2017 (UTC)

• Our article on gravitons (which emerge in many quantum gravity and string theories) has a quite entertaining discussion of how rare the interaction between gravitons and matter would be, and how large a detector you'd need to see one (spoilers: the required neutrino shield would be so large it would immediately collapse into a black hole). Smurrayinchester 08:59, 10 July 2017 (UTC)

Learning/teaching systems thinking

How can we learn or teach systems thinking? --Hofhof (talk) 19:30, 9 July 2017 (UTC)

First it needs a definition. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:52, 9 July 2017 (UTC)

It seems to be mainly founded on logic. Learning logic is a mix of understanding the principle and then practice repeated application to achieve a lasting imprint in out memory. --Kharon (talk) 09:07, 10 July 2017 (UTC)

That makes no sense Kharon. According to the corresponding articles - systems thinking and systems science - and to a trivial logical analysis systems include any kind of field that has an effect on an issue: cognitive, society, science, math. I'd bet a good 'systems thinker' has broad general knowledge about the involved issues. --Clipname (talk) 16:22, 10 July 2017 (UTC)

irrelevant comment
Looks to me like you dont know how much of our world is based on logic. Maybe i can convince you with irony: Ask an economist! They are said to teach the worst in both, bending all reality to their "logic" and "making sense". --Kharon (talk) 18:00, 10 July 2017 (UTC)

This is WP:NOTAFORUM for abstract debate, my friends. The OP's question is arguably too broadly phrased for us to answer without engaging in extensive speculation (which is not the point of this space); the thread can stand for the purpose of providing references that might be useful, but not our personal opinions. On that subject, the OP may be interested in the works of Fritjof Capra, who has made a decades-long endeavour out of trying to find ways to encourage systems thinking in the mainstream. In particular, The Turning Point may be off interest, as might Mindwalk, a quasi-narrative film that is based on his works. Snow ^{let's rap} 23:42, 10 July 2017 (UTC)

By not shying away from hard core reductionism. E.g. Biology = systems chemistry, see also here and here. Count Iblis (talk) 02:07, 11 July 2017 (UTC)

What temperature range can feral pigeons survive in?

At what temperature do they start feeling uncomfortable? Do these numbers change with the seasons? If so, what are the seasonal adaptations and what triggers them? Does the climate of an area feral pigeons are introduced to selectively concentrate the subspecies and sub-subspecies most fit for that climate? (similar to how the European climate selectively concentrated white people) Sagittarian Milky Way (talk) 20:11, 9 July 2017 (UTC)

I can attest that below −20°C they start feeling uncomfortable (seeking warm place). Ruslik_Zero 20:36, 9 July 2017 (UTC)

For the last bit, sure. We have shitty sub at species sorting but if you search that and "environmental filtering", you'll find lots of research and information about how species' abundances are tied to adaptation to local climate, resources, etc., and how that ties in to natural selection Careful about using the term "most fit" though, it's not a very good term, and tends to be used by people spouting discredited social darwinism. It may be that the feral pigeons of Minneapolis have slightly different traits than those of Miami, due to natural selection, but by virtue of stably persisting, they are all equally fit as populations. I'd WP:OR not be surprised if a box of pigeons moved from WI to FL had slightly less reproductive success than their native-born counterparts, but I'm not aware of any studies on the topic, nor could I find any. This [8] recent paper has some nice discussion of the genetic variation, convergence, divergence, etc. of feral pigeons. There are also some comments on how/why local populations may differ. I only skimmed it, but if you read it carefully and look at some of the refs (and look at papers that cite this one [9]), you'll know more than you even wanted to about pigeon genetics and spatial distribution! SemanticMantis (talk) 19:10, 10 July 2017 (UTC)

Oh, and this paper [10] is all about geographic variation in pigeon size, and explicitly invokes natural selection by environmental variable acting on heritable size traits. It's surprisingly right on target for explicitly answering your question, that's rare, so enjoy :) SemanticMantis (talk) 19:13, 10 July 2017 (UTC)

Thanks. Sagittarian Milky Way (talk) 19:28, 10 July 2017 (UTC)

Also of interest may be adaptive radiation (which is very general, but also affects birds in large continuous ranges). —PaleoNeonate - 19:38, 10 July 2017 (UTC)

July 10

Ground locomotion of birds

Today I saw a sparrow hopping and a pigeon walking. That got me to wondering—is there a pattern in bird taxonomy that predicts which ones hop and which ones walk? Or is there some other determining factor such as weight or the general environment they're adapted to? I couldn't find this out from our articles on locomotion or birds. Loraof (talk) 01:38, 10 July 2017 (UTC)

Then there's the odd-looking method of walking some birds use, where they hold their head stationary while walking, then jerk it forward, and repeat the cycle. This seems to be necessary because their vision system can't cope with movement of the eyes particularly well. In particular, their ability to detect objects in motion is compromised when everything is in motion, relative to them. As for hopping versus walking, is it just a matter of size ? It seems to me that small birds tend to hop while larger birds walk or run. (Of course, there are large mammals which hop, like kangaroos, but they have massive leg muscles, which would interfere with flying in a bird.) StuRat (talk) 05:49, 10 July 2017 (UTC)

What birds are you referring to that keep their heads still and move their bodies forward. Richard Avery (talk) 07:37, 10 July 2017 (UTC)

Pigeons, for one. Matt Deres (talk) 15:48, 10 July 2017 (UTC)

And chickens. (I got to watch them a lot this weekend.) Dad remarked that all their head motions are jerky, even when their feet are not moving; I said well, I guess, when your head muscles are adapted for staccato … —Tamfang (talk) 16:45, 10 July 2017 (UTC)

Yes, the same problem applies when they turn their head. If they did it slowly, they wouldn't be able to detect motion during the turn, so they do it quickly, so as to minimize the time when their vision is impaired. Sort of like how we blink, for the same reason. But apparently one thing a bigger brain does get us is the ability to detect relative motion even when our heads are moving. And not just us, but birds with larger brains seem able to do this, too. StuRat (talk) 17:25, 10 July 2017 (UTC)

Stu. Don't post your opinion and intuition as fact, please. This is all quite wonderful and fascinating speculation to you, I'm sure. But it's also all amateur guesswork, and completely inappropriate for a reference desk. For references that actually describe our knowledge on the topic, look at chicken cam image stabilization, e.g. here [11] or here [12] or even look at the scholarly literature on head-bobbing in chickens [13], [14] . Why make thing up? Especially when even a casual search on google scholar gives plenty of good references on the topic. Please research and include references when posting. Your guesses are well-intentioned I'm sure, but not helpful, and in this case misleading. You know better by now. You can do better. I know you can ;) SemanticMantis (talk) 01:23, 11 July 2017 (UTC)

Almost all birds can and will do both, walking and hopping, depending on their mood and situation. Some birds even dance sometimes! Some dance formal and slow paced, some like going wild. I think the determining factor is their default stance/degree of aggression and that shure fits our view of the peacefull pigeons. --Kharon (talk) 08:36, 10 July 2017 (UTC)

It has to do with energy conservation. Birds do whatever gets them what they want with the least expended energy. Smaller birds tend to hop because it uses very little energy and gets them where they want to go quickly. Larger birds tend to walk because it requires less energy to do so. There are exceptions. Further, birds who spend most of their time foraging in trees tend to hop because walking from branch to branch is hard. Birds who spend most of their time foraging on the ground tend to walk. [15] [16]. I personally believe it has to do with society as well. I live in South Carolina. We have sandpipers. They run quickly from place to place. When I was in Bermuda, I noticed that their sandpipers hop instead of run. I'm certain it is a different type of sandpiper, but my gut tells me that the Bermuda ones hop because they see all the others hop. The Carolina ones run because they see all the other ones run.209.149.113.5 (talk) 12:30, 10 July 2017 (UTC)

Great answer and references, thanks. But I have to weigh in on your last comment "...because they see all the others hop": I can find no evidence of any bird where a hopping species can be trained to walk, or a walking species can be trained to hop. Hopping vs. walking seems to be purely set by species, not culture/learning, as far as I can tell, and that is the perspective of the research I link below. SemanticMantis (talk) 14:11, 10 July 2017 (UTC)

I intended to make it clear it was my opinion and my opinion was completely unfounded. After searching, I found numerous resources claiming that sandpipers hop on one leg in colder climates. I was Bermuda in February, so it was colder than the South Carolina beaches. Perhaps if I go to North Carolina, I will find hopping sandpipers. 209.149.113.5 (talk) 14:51, 10 July 2017 (UTC)

All good, I was just offering a contradictory viewpoint. No need to strike out your text, you did make it clear it was speculation, and it might even be true! I'm a bit chagrined that I cannot (yet?) find a good reference that explicitly addresses my claim that that walk vs. hop is almost totally genetic, but I'm getting close. Here [17] is the best work I can find so far on multiple gaits within a single species, discussing walking, running, and (out of phase) hopping in the magpie. It does casually mention that "most species use only one or two gait types," viewing these magpies as a bit of an outlier. This paper [18] has a very good reference list in the introduction, and says that "patterns of walking, running, and even hopping are conserved among birds". This would indicated that gait is a conserved trait taxonomically speaking, i.e. that we'd generally expect many members of a given bird clade to share the same gait, though this does not rule out some members using derived gaits. SemanticMantis (talk) 15:28, 10 July 2017 (UTC)

Here [19] is a nice analysis of how bird morphology influences striding gaits. Hopping is not considered, but it does give good background on energetics, morphology and gait. As for hopping vs. walking, this recent research (2013) [20] finds that "Cervical movement capability is perhaps the single most deterministic factor in the bird's choice of terrestrial gait. [i.e. hopping vs. walking]" SemanticMantis (talk) 14:11, 10 July 2017 (UTC)

It would be interesting to see a proper study of the difference. Astronauts on the moon found it easier to move around by hopping. Dmcq (talk) 15:01, 10 July 2017 (UTC)

See the article Bird feet and legs. After they evolved the ability to fly, other kinds of locomotion such as walking, running, hopping, climbing, swimming became of secondary importance and these abilities evolved differently in various bird species. An essential hindlimb function is to accelerate when taking-off and to absorb the shock of landing. Further adaptations in specific bird species are to use the feet as "hands" (the forelimbs being reserved as wings) for manipulations such as grasping a perch or prey, pulling food apart, scratching the ground, building a nest, turning eggs, self preening, etc. Efficient ground locomotion became critical for survival only in the cases of birds losing the ability to fly which has occurred in many different birds independently, generally in situations of no ground predators or deliberate selective breeding by man. They include flightless domesticated Fowl (chicken, turkey, duck), penguins, and Ratites (ostrich, moa, emus,...). The pectoral muscles for flight decrease and the pelvic girdle for running enlarges. Blooteuth (talk) 15:05, 10 July 2017 (UTC)