Wikipedia:Reference desk/Archives/Science/2018 March 11

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March 11

Jiggling nervously your leg

Is there a scientific name for the act of jiggling nervously your leg? Is there an article about it, causes and such?--Hofhof (talk) 00:13, 11 March 2018 (UTC)

Google "jiggling leg nervously" and see if you like anything that turns up. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:39, 11 March 2018 (UTC)

No, I didn't like anything that turned up. --Hofhof (talk) 01:51, 11 March 2018 (UTC)

The only thing that comes to mind is Restless legs syndrome, but I think that's somewhat different from what you're describing. Although one good term for it might be "fidgety". ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:15, 11 March 2018 (UTC)

Also, see this:[1] ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:42, 11 March 2018 (UTC)

If it's voluntary, you're just jiggling your leg. If it's not, there's restless legs syndrome and focal seizure. But probably you're just jiggling your leg. _ Nunh-huh 02:13, 11 March 2018 (UTC)

You may also be interested in searching for "non-exercise activity thermogenesis", or NEAT. We don't seem to have a specific article on it, but thermogenesis mentions it. --Trovatore (talk) 05:07, 11 March 2018 (UTC)

If I've interpreted Hofhof correctly, then the question is about a semi-voluntary movement at about the frequency of a shiver or a slow tremor that occurs when the leg is in a certain slightly stretched position with the toes on the floor. It can be voluntarily reproduced by many people, but can occur involuntarily when the person is nervous, stressed or cold. I've no idea what it is called, and I can't find an article. It is slightly too fast for a deliberate muscle movement initiated in the brain, so it must be some kind of muscle feedback loop. Dbfirs 12:59, 11 March 2018 (UTC)

At about 5:20 Menashe's right leg begins to move in the way that I think is being described by Hofhof. The movement seen there is faster and with a range of motion shorter than what I have most often observed. But I think this is a very common, rapidly repetitive motion observed in many people. In my experience it always involves a seated person. It may be seen more commonly in males. These are all just my own observances. I have no sources to provide and I know of no references to this sort of thing. But it does seem like it could have a name—be it scientific or otherwise—and it would seem to me likely that it would be described in some literary entity. Bus stop (talk) 13:32, 11 March 2018 (UTC)

Here is a video relating to this phenomenon. And this. And this. I cite these merely as references. Of course I am not endorsing any of the commentary accompanying the references. Bus stop (talk) 13:38, 11 March 2018 (UTC)

See 貧乏揺すり translation _{just realized I'm doing it myself} --catslash (talk) 16:16, 11 March 2018 (UTC)

Googling binboyusuri gets this instructive video. --catslash (talk) 16:27, 11 March 2018 (UTC)

We can say that we have confirmation that others have observed this phenomenon. I am hopeful that Hofhof will weigh in to tell us if what we observe is on the right track. Bus stop (talk) 18:51, 11 March 2018 (UTC)

This language forum thread on the subject also fails to find a name for it. I know a couple of people who have this habit, very annoying when you're sitting on the same settee. This anxiety forum thread finds numerous self-confessed leg-bouncing addicts, but still no name. Alansplodge (talk) 22:03, 11 March 2018 (UTC)

I took this to the Web and found this thread; scrolling down past the psycho-babble I found something that matched my subjective impression, the stretch shortening cycle as a means of establishing the frequency of shaking. However, the way our article puts it, it doesn't sound like much of a cycle, and I couldn't quickly substantiate the claim. The forum also claims that this is a way of using skeletal muscle to improve venous return from the leg, e.g. to prevent deep vein thrombosis; I find this plausible, and confirmed by another forum thread (sigh)... but that one mentions that "sedentary behavior" applies to the general field. Looking that up, I can graduate to a Japan Today article [2] that calls various kinds of foot fidgeting "bimbo-yusuri". This is still a broader term including things like crossing and uncrossing legs, but maybe I've nicked the whale, let's see... apparently in Japan, as with almost anything, people are intimidated against it for fear of discrimination [3], but more importantly, that source cites an actual study about it. Well, "cites" is the wrong word since they do their level best to obfuscate the link, but they couldn't resist the temptation to use the number 12,778, which gets me the Tribune [4] and the name of the journal. Searching their archives for September 2015 got me nowhere, but using the journal name and the magic number I found the article from February 2016, five months after the popular press report - [5] Alarmingly, there seems to be some issue with Sci-Hub over Tor at the moment - should find out more about the latest round of persecutions - but there may be a technical term buried in there somewhere, as well as allegedly a claim that it reduces mortality 30%. Wnt (talk) 15:10, 12 March 2018 (UTC)

Seems like a form of stimming, commonly thought of as something people on the autistic spectrum do, but no reason neurotypicsl people mightn’t also do repetitive muscular activity when they are nervous or bored. It could serve as a way to annoy others until some authority angrily orders you to stop. It seems to make the leg feel better. Maybe it stimulates circulation or just exercises the muscles a bit. Edison (talk) 17:37, 12 March 2018 (UTC)

The word you guys are looking for is fidgeting. Abductive (reasoning) 06:38, 18 March 2018 (UTC)

Ceramic tiles for a sound-proof box?

A friend in a wamer climate sent me a cryptocurrency ASIC which will give me free heat (he'll pay for the electricity) in my cold climate but I need to build a suitable enclosure to minimise the noise. I have started to use 25 mm MDF and 30 mm sound-deadening foam and this helps a lot but it's still quite noisy. Would it help much to put ceramic tiles between the foam and the MDF? I read that ceramic tiles are sound-reflective due to their hardness and smoothness but I'd like to know whether it's a good idea before I buy any. --185.222.218.3 (talk) 07:11, 11 March 2018 (UTC)

In soundproof boxes for printers there would not be any ceramic tile. I suspect it has similar properties to the MDF. Instead the acoustic foam has a textured surface, to reflect the sound in different directions. To improve the performance you can put the box in yet another box, with the inner box resting on a bed of sand. Hopefully there are no windows, and the holes for the air to circulate must also be small enough to impede sound. Another way to change the sound may be to change the fan that I assume is there to a more silent one, or to replace it with fluid cooling. (like water cooling). Graeme Bartlett (talk) 08:03, 11 March 2018 (UTC)

Designing soundproof enclosures rather depends on the frequency content of the sound. You also need to make sure that there is no structural transmission of vibration. Any modern phone will have a spectrum analyser app. Rather trickier is deciding which part of the noise spectrum is annoying you. In general bricks are good, wood is bad. Greglocock (talk) 08:38, 11 March 2018 (UTC)

• As Greg notes, soundproof enclosure design is complex and depends heavily on the frequencies involved. What are those frequencies, and how are they travelling? Broadly, high frequencies will travel through the air and around corners, low frequencies will go through the walls of the enclosure, or even along those walls.

Your best approach is to reduce the noise generated. I've not seen any of these low-end ASIC machines which have been at all well designed for efficient cooling or low noise. They're not even designed for proper rack mounting. If you look at how servers are racked up, especially blade servers, that might give you some ideas. In general, try to get efficient airflow through the hot parts of the enclosure (maybe not so much over the cooler parts) and keep peak temperatures even everywhere (a cheap IR camera such as the FLIR One [6] is good for this, or even a really simple IR thermometer). It is much more efficient (in air moved / noise dB) to use a single large fan, rather than multiple small fans. Better designed fans will have features like sawtooth fanblade edges and better guard bars. My home office servers are two 20 year old HP Kayak machines, single fan each, because these are still the best designed tower case machines I've seen for airflow - they're now on about their fourth set of motherboards. Even better is to avoid fans as much as possible, by using thermosyphon cooling, although this might work for cooling the rack but you still need fan-forced air to get airflow through the smaller passages around the hotter parts of the board.

For soundproofing, I'd expect this to be medium-higher frequency white noise, rather than low frequencies. If you have mechanical noise, use better fans. If there is mechanical vibration from the fan block, isolate that as a separate unit on rubber blocks or elastic bungees (silicone wristbands are good, and don't age like rubber does in electronics enclosures). Then line the inside of the main case with a foam or wool liner, which absorbs high frequencies rather than reflecting them. A thin layer of rockwool roof insulation under stapled-down netting is cheap. The inlet and outlet ports also need to be lengthened tubes, lined on the inside, so that there's no direct line-of-sight path in an out of the enclosure (or sound will just travel that way). Make sure the ports are big enough to allow good airflow, and their outer edges should be rounded with trumpet bells, not sharp corners. I _wouldn't_ fan blow the entire airflow - allow a lot of it to be thermosyphon, and just use the fans to blow cold inlet air where it's most needed.

Then check the thermal management again, with the sound box in place. Do it again after an hour - recirculated air paths inside can get hotter and hotter.

Mostly I'd look at re-racking these things. As noted, I've not seen one of these coin miner rigs that was competently designed, compared to modern blade servers. Andy Dingley (talk) 11:12, 11 March 2018 (UTC)

Just a follow-up question: something that isolates noise, will also isolate heat. If you are in the same room with the ASIC, the heat will trickle anyway, but how will you avoid the ASIC from over heating? Hofhof (talk) 15:45, 11 March 2018 (UTC)

Its no problem to wrap up a noisy box with enough layers of foam patches to make it silent. Heat transfer/cooling can be silenced too. You either add some liquid cooling system and use its radiator as your heating or you keep using your air/fan cooling but build Labyrinth seal like artificially lengthened paths with similar foam patches separate for your air in- and out channels. The only drawback of the labyrinth approach is the need for some additional space, which is why its usually not used in professional solution no matter its cheaper and more reliable. --Kharon (talk) 17:59, 11 March 2018 (UTC)

In a real life scenario you could also place the ASICs in the basement, and transfer it like in this datacenter in Finland. Hofhof (talk) 18:19, 11 March 2018 (UTC)

Basement? The OP seems to be from the UK. Nil Einne (talk) 04:54, 12 March 2018 (UTC)

• "something that isolates noise, will also isolate heat"

No. Heat is removed by convection - the physical movement (blown or thermosyphon) of heated air. To do this quietly you need to achieve several things: convection to remove the heat, removing the HF sound from this convecting air (absorbent surfaces on the exhaust duct), not generating any new noise from the air movement (quiet fan designs, quiet inlets and outlets without resonances or sharp corners), not transmitting any LF conduction noise through the structure. Andy Dingley (talk) 20:31, 11 March 2018 (UTC)

To be more precise: if something produces heat at a roughly constant rate within a box, on the long run what is within the box does not matter to the heat that is exchanged with the outside (the power output observed outside is the same as inside, because thermodynamics). What might happen though is that a critical part of the something overheats and fails, so if you want to avoid that, you need some kind of thermal exchanger and (as described above) those will put a price tag on the "noiseless" requirement. Tigraan^{Click here to contact me} 17:04, 12 March 2018 (UTC)

Poisonous orchid?

Is there really a species of orchid which is native to the jungles of Brazil and which is poisonous to humans, but not to most animals? Or did Ian Fleming invent it, just as he invented "skin suffocation"? 2601:646:8E01:7E0B:71B8:6856:E929:5E71 (talk) 09:58, 11 March 2018 (UTC)

A quick googlesearch on "poisonous orchids" brings up several assertions that "there are no known poisonous orchids", but I wouldn't be inclined to trust absolutely anything not coming from professional botanists. However, the frequency of such claims in the present day suggests that Fleming wouldn't have known of any claimed or actual poisonous orchid when he wrote the book, and therefore likely invented it. The books were intended as light entertainment, so I doubt Fleming would have bothered to carry out deep research for such a minor detail: that it seems plausible to his readers would have been sufficient for his purposes. {The poster formerly known as 87.81.230.195} 90.211.131.202 (talk) 12:19, 11 March 2018 (UTC)

Some interesting material here. If Fleming had a bunch of ornithology books kicking around, maybe he had that book as well? Matt Deres (talk) 01:59, 13 March 2018 (UTC)

Can you elaborate? I can't read the source -- it's paywalled! 2601:646:8E01:7E0B:0:0:0:64DA (talk) 06:35, 13 March 2018 (UTC)

Invasion of a home by ants

Yes, I do have this situation. We've lived here for about 3 years and only about 3 months ago, in the middle of the winter the pests began coming in. With the weather getting warmer their numbers multiplied. There is only one small area in one of the bathrooms affected, perhaps 3 feet wide. My wife, naturally, goes nuts. I called the exterminators and made an appointment. Immediately my daughter and son-in-law came for a visit and said: cancel it, they will kill your cat and poison you.

Is it a realistic scenario?

Thanks, AboutFace 22 (talk) 16:41, 11 March 2018 (UTC)

We have had periodic spraying for ants and other pests, and our cats and ourselves are just fine. Once the spray they use has dried (about half an hour) then it's safe to put your cat back on the floor. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:50, 11 March 2018 (UTC)

ants in your house? Realistic. They will kill your cat? Possible. They will poison you? Unrealistic. I use AntRid. Greglocock (talk) 17:09, 11 March 2018 (UTC)

A professonal exterminator might also have a theory on why they're (apparently) only there, where they're coming in, and what they're feeding on. Ants don't come into your house to be annoying, they come in looking for food. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:13, 11 March 2018 (UTC)

Professionals fight Insects with specific poisons which are no serious thread to Mamals aka breastfeeding species. Nevertheless they are still poisons so pets and children should be kept away. Ants should be easy to fight off without poisons and they usually can not do any harm unless they are Fireants or another of the very few dangerous ant species. Best read a bit about ants and try to identify the sort simply by finding out what ant species are common in your area. Ask your wife to find out about them on the internet so she maybe looses her fear. --Kharon (talk) 17:27, 11 March 2018 (UTC)

Thank you. Every contribution is valuable. AboutFace 22 (talk) 18:31, 11 March 2018 (UTC)

I'll just note that what works against one species of ants may not work against another. I live in Toronto and there are two kinds of ants that get into my house from time to time: one species that I've seen for decades and another species about half the size that I've only been seeing for maybe 10 years. For the first species, I can buy what the stores call ant traps or ant baits. Since Wikipedia doesn't have an article under either name, I'll explain: these are little containers that you punch a hole in and set down on the floor or wherever the ants ago. The idea is that the ants go into the container, mistake the toxin for food, and carry it back to where they live. However, in my experience this method doesn't work at all against the smaller ants. For them I use an aerosol insecticide that you spray onto the floor and it leaves a residue. It has been effective against that species and hasn't hurt our cats, but I'm not presenting this as general advice. A professional who sees the ants might know what will work against the ones you have. But on the other hand it might cost a good deal more than the right product you can buy in a store, if you know what the right product is. Maybe you should talk to your neighbors. --69.159.62.113 (talk) 18:48, 11 March 2018 (UTC)

We do have Pest_control#Poisoned_bait- it briefly mentions ant and roach baits, but isn't that informative. This is in the section on Physical_pest_control, but our dedicated article on Physical_pest_control doesn't currently include anything on insect baits. Anyone else find relevant WP articles? Seems like a big weakness, at the least some redirects may help in the short term. SemanticMantis (talk) 02:13, 12 March 2018 (UTC)

• You've essentially omitted all the information needed to get a useful answer. Where do you live? A place where ants can survive outside in winter? Or is the source colony inside your building somewhere? How are they getting into your bathroom? What kind of ants are they? Looie496 (talk) 23:44, 11 March 2018 (UTC)

Agreed, those details are all very important for determining what the ant problem is and how to solve it! But I'm not so sure they help answer the question asked: whether it is realistic that a local exterminator will kill pets and human residents when hired to get rid of ants. I'd WP:OR rank both human and pet death as "extremely unlikely" when dealing with a licensed professional, but I have no WP:CRYSTAL.

I'd encourage OP to specify these and perhaps ask a new question if they want references and info on dealing with ants in the house :) SemanticMantis (talk) 02:05, 12 March 2018 (UTC)

In this country infestations are almost always of ghost ants or pharaoh ants. I thought these were alternative names for the same insect but there is a difference. The preferred method of treatment is to smear bait around the crevices from which they emerge. This clings to their bodies and they take it back to their nest, where it renders the queens infertile. 86.152.81.89 (talk) 12:45, 12 March 2018 (UTC)

Which country? Your answer doesn't match your IP geolocation. Dbfirs 13:17, 12 March 2018 (UTC)

I will try to answer some of the questions, however I doubt the answers will help me to combat the problem. I live in Salt Lake City, Utah, suburbs. We had a rather brief but significant period of snowfalls and the ants began to come in in small numbers first when there was at least 2 feet of snow in the yard, right under the place where the bathroom counter with two sinks is located. They crawl from under that counter and travel across a tile floor. I was wondering how could they survive out there, very mysterious. Now it is of course much warmer, the snow is gone. I did buy a trap at Amazon.com and will try to set it up today, perhaps in less than an hour. I will try to read other posts and see if I missed some questions I need to answer. I will also try to measure the ants. Thank you all. AboutFace 22 (talk) 16:58, 12 March 2018 (UTC)

Many ants such as ghost ants and carpenter ants depend heavily on a water source. Either a leak from the sink or condensation forming on pipes could help sustain them, as could leaks from snow piled on rooftops that forms ice dams and leaves water to seep inward etc. If you stop the water, you should stop the ants for good. Wnt (talk) 18:06, 12 March 2018 (UTC)

Rather than measure the ants, just take a photo of them crawling over a ruler and post that. We can tell more from the image (but that is only to satisfy our intellectual curiosity), ( it may also indicate that they are ants that thrive in a moist eviromet) . As said above. If you live in the civilized world, your pest exterminator will be licensed to indicate that they are competent enough to place 'poisons' in a domestic residence in a way that will not poison your pets (but at a great cost to you and they will have to come back to repeat the treatment again and again, year after year). Modern ant treatments (bought off Amazon) come with instructions that inform the home owner where to place it the so they don't accidentally poison pets. Finally, don’t matter what type of ants you're infested with. Good old inexpensive borax and sugar is efficacious against all ants. Maybe it is because it is old fashioned and not dependant on the latest high tech chemistry (promoted heavily by the chemical companies that have developed them), it has been ignored by modern home owners with more money than sense. However, don't ignore your daughter and son-in-law concern. Some household quick-solutions can be very detrimental both to you, your cat and anybody else living under your roof. --Aspro (talk) 19:04, 12 March 2018 (UTC)

Again thanks for contributing. I am embarrassed to say that I cannot add much information now. I went home on my lunch break and did not have enough time to install the traps but my wife said something that attracted my attention. She said that there were no ants today. Is it possible that they kept coming in in cold weather just to get warm and now when the temperature is $58^{o}$ outside they don't need us? It needs further investigation though. AboutFace 22 (talk) 20:29, 12 March 2018 (UTC)

When your wife said “that there were no ants today” it means the same as she didn't 'see' any ants today. Doesn’t mean that there where no ants. But don't fret. Sounds like you don't have a bad infestation. The trap you bought will probably work well. But what about next year? Borax & Sugar is so cheap and is only mildly toxic. Place it where cats can't get at it (but ants can) and you might start missing them. Ants are ecologically fit to recycle organic matter – like the warm damp wood in your bathroom when it is cold outside. But borax will not only deprive them (and their poor little baby ants) from a living but will kill them too. Might make the chemical companies very upset, that your not buying their very expensive products. Yet what do you want to spend your money on? Making them rich or getting rid of your ants? And they are your ants. If you provide a suitable habitat for mother nature to colonize -you only have yourself to blame. --Aspro (talk) 21:37, 12 March 2018 (UTC)

Borax is a chemical compound, and can be harmful to children and pets in sufficient quantity. I remember that it was no magic bullet where some roaches I had were concerned. But a good exterminator, besides deploying toxins one hopes are non-toxic, will also give you recommendations about any leakage of water; so if he's coming, you might as well try to dry up any such sources in advance so as to give him more time to poison the ants. Wnt (talk) 00:26, 13 March 2018 (UTC)

Yep, @Aspro is correct, I should not have said that. It turned out to be a "fake news." Later in the day she was crawling on the floor collecting them with a wet wad of paper. She uses soapy water for that. Realistically I cannot do much in terms of setting traps for them until Friday - when my weekend starts, I am really too busy every day at work and with domestic chores too. However I really appreciate all the contribution and will use them in my fight against the ants. AboutFace 22 (talk) 15:07, 13 March 2018 (UTC)

Ants hate cinnamon, if you want to exclude them from a food source... Abductive (reasoning) 06:41, 18 March 2018 (UTC)

I didn't know about cinnamon, but when the kitchen was infested by ants I solved the problem by placing the food in a dish which I balanced on a tumbler in a bowl. I then filled the bowl with water to form a moat. The ants realised the game was up and disappeared within a few hours. Of course, if you possess a refrigerator you could put the food inside, since it appears they don't like cold either. 86.152.38.231 (talk) 16:35, 18 March 2018 (UTC)