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July 14

Before seeking FDA approval of a drug in the USA, how do they test the drugs for infants or children?

When a drug is seeking approval by the FDA in the USA, how do they test drugs for infants or children? Joseph A. Spadaro (talk) 05:16, 14 July 2016 (UTC)

See Clinical trial and Ethical problems using children in clinical trials (which, based on its current content, would be better at a more neutral title). Tevildo (talk) 08:25, 14 July 2016 (UTC)
(edit conflict) Do you mean drugs specifically intended for infants and children? That case is rare. Most often a drug gets approved as safe and effective for adults and is only subsequently studied in children. In general we have articles on drug development and new drug application. Dragons flight (talk) 08:29, 14 July 2016 (UTC)
Thanks. This is what I am saying/asking. When drugs are approved for adults, they have -- at some point -- been tested on adults (through clinical trials, etc.). Oftentimes, when we (adults) take drugs, there are warnings that say "this drug is not approved for anyone under the age of 18" (or some such). Now, obviously, little kids (infants, children, teens, etc.) all take medicine and drugs. So, how do those get approved for them? I can't imagine they subject infants and children to be subjects in experimental trials and/or clinical trials. Thanks. Joseph A. Spadaro (talk) 12:59, 14 July 2016 (UTC)
Ultimately, yes. Children do participate in clinical trials with parental consent. Most often the trial is for a drug already approved for adults. If it is life-saving medication, then the benefits will generally be viewed as outweighing the risks. Doctors are also able to legally prescribe drugs to children that haven't been formally tested and approved for children if in the doctor's judgement such a off-label use is medically appropriate and inform the parents accordingly (usually the dosage is adjusted for a smaller body weight). This interesting article describes efforts by the FDA to increase drug testing in children. Dragons flight (talk) 13:12, 14 July 2016 (UTC)
Thanks. So, let's just look at infants, for example. I can't imagine it's a high number of parents that allow their infants to be guinea pigs. When they conduct tests, don't they need some statistically significant sample size? Joseph A. Spadaro (talk) 14:30, 14 July 2016 (UTC)

Thanks, all. Joseph A. Spadaro (talk) 04:40, 16 July 2016 (UTC)

Chem elements in the infoboxes

I noticed that now our articles on chemical elements display atomic numbers alongside Latin designations in the form of 26Fe (iron), 13AI (aluminium), etc. However, I was taught in the school that an element is simply designated by its Latin abbreviation (Fe, Na, etc.), not like 26Fe. If this is related to stable isotopes, I think it's redundant. Are we doing the right thing?--93.174.25.12 (talk) 12:11, 14 July 2016 (UTC)

Yes, it is redundant. But I think in the infobox title (the sole place it is used) it serves the purpose of highlighting the relationship in which atomic number determines the element. If you wish to discuss this with editors that are involved in making these decisions, Misplaced Pages talk:WikiProject Elements would be the best place to do so. ChemNerd (talk) 12:15, 14 July 2016 (UTC)
I agree with ChemNerd. The one- or two-letter abbreviation that the OP is describing as Latin designations are correctly called chemical symbols. Only a small number are based on the Latin name for the element (eg iron is Fe because the Latin word for iron is ferrum.) The majority are closely related to the English name for the element (eg hydrogen is H; lithium is Li.) Dolphin (t) 12:52, 14 July 2016 (UTC)
Actually, the symbols for hydrogen and lithium both derive from Greek, just FYI. EdChem (talk) 13:13, 14 July 2016 (UTC)
The names hydrogen and lithium indeed derive from Greek ὔδωρ γεἰνομαι and λιθος, but the symbols do not come directly from the Greek, but rather from whatever language Berzelius was thinking of when he came up with his symbols. Double sharp (talk) 15:30, 14 July 2016 (UTC)
Nothing to do with isotopes either - all isotopes of Iron have the same atomic number (26). The variation between isotopes lies is in the atomic weights (which range from 54 to 60). Wymspen (talk) 15:48, 14 July 2016 (UTC)
  • The atomic numbers in the lower left corner come from an expanded notation known as isotope notation. Yes, the numbers ARE redundant with the symbol, since there is a near perfect one-to-one correspondence between atomic number and symbol (excepting for the isotopes of hydrogen which each have their own symbol). The purpose of sometimes including the atomic number is twofold. First (and of lesser importance) is that it can serve as a sort of checksum, that is a way to make sure there isn't an error or typo somewhere. The most important use is in nuclear reaction equations; since atomic numbers and mass numbers are always conserved in nuclear equations, explicitly writing the atomic number makes the math more visual. --Jayron32 14:06, 15 July 2016 (UTC)

Deflection how much is safe?/

i have done fem study to find out deflection in structure.Is there any theory of failure to tell me that this deflection is safe or not .material is steel. — Preceding unsigned comment added by 112.133.223.2 (talk) 13:19, 14 July 2016 (UTC)

There are commercially available (though expensive) computer programs (doutbtless employing fem "under the hood") that can carry out such analyses, provided that the users are trained and competent in putting in all the parameters correctly. University-level courses in structural engineering and allied disciplines doubtless mention such programs, although work placements in working engineering companies might be necessary for training in using them in practice.
It's possible to carry out such a calculation for a single structural member on paper, but most scenarios in the real world involve complicated structures with many components, where a non-computer calculation would be unfeasibly difficult and long. (Obviously, such calculations were performed before the advent of computers, but they required vastly more personnel than would be available today, and of course some structures did subsequently fail.)
Given that structural failures can in many circumstances result in deaths, this is not an area that can safely and legally be dabbled in for real-world applications by the untrained. {The poster formerly known as 87,81,230.195} 2.123.26.60 (talk) 14:49, 14 July 2016 (UTC)
(ec) This has been studied extensively, and there are many issues here:
  • First, you need to ensure that the deformation is within the elastic deformation range, where the object will return to it's original shape, not the plastic deformation range, where it will only partially return.
  • Then metal fatigue must be considered, which is sudden fracture by a metal bent within it's elastic deformation range, an excessive number of cycles.
  • Also, the center of gravity of the building moves as it deforms, and you must ensure that the CG point is always within the edges of the foundation, or then the weight forces holding the building in place would instead work to topple it over. This is only a potential issue on tall, narrow buildings. StuRat (talk) 14:54, 14 July 2016 (UTC)
The basic approach would be to calculate the maximum stress of each type (which involves determining where in the structure the maximum stresses occur) and comparing these stresses to the appropriate strengths of the material. In spite of the one sentence description, this will likely be complicated.--Wikimedes (talk) 06:00, 17 July 2016 (UTC)

Is there an Aether?

The recently published book from the late Selwyn Wright backed up with several peer reviewed papers makes a very good case for an aether. This fundamentally conflicts with Einstein's relativity, but makes much more sense for measure movement from a static aether than just relative movement from two points, thus getting different equations from observer and event. He also shows how Einstein may of misinterpreted experiments to determine ether(prior to Special relativity) due to the fact that the aether turns with gravitational bodies (Also that the aether is static away from gravitational bodies in space).

Does this mean the teaching of relativity should be updated?

Selwyn addressed the experiments for aether and how they were misinterpreted but also uses later experiments to back up the claim and also suggests some other simple tests that could be done utilising the better equipment we have at our disposal today, if more proof was needed — Preceding unsigned comment added by 80.194.75.50 (talk) 14:44, 14 July 2016 (UTC)

It may well depend on how you define it. There doesn't appear to be much normal matter in the intergalactic void, but there may be dark matter or dark energy. Also, you could consider the space-time continuum to be a form or aether. StuRat (talk) 14:58, 14 July 2016 (UTC)
The validity of Professor Wright's theory is a matter for the scientific community to decide on by the usual processes. This does not yet appear to have happened, but it's early days yet.
It appears to this layman that there might be a good case for a Misplaced Pages article on Selwyn Wright, but others would be more competent to judge. {The poster formerly known as 87,81.230.195) 2.123.26.60 (talk) 15:02, 14 July 2016 (UTC)
Draft:Selwyn Wright already exists, so you have something to start with. Wnt (talk) 16:33, 14 July 2016 (UTC)
Here's a web page on "new relativity". He's just a typical crank. There are a lot of them. His particular area of confusion seems to be the Sagnac experiment. The ten peer-reviewed papers mentioned on the web site (in the sidebar on the left) are all conference papers from Progress In Electromagnetics Research Symposium. I don't see any evidence that it's a fake conference, but it's clearly not the right venue for this type of work and their reviewers clearly don't know anything about special relativity.
Of course, this has nothing to do with whether Wright should have a Misplaced Pages article. But I see nothing to suggest that he should. -- BenRG (talk) 17:42, 14 July 2016 (UTC)
See also . --71.110.8.102 (talk) 23:50, 14 July 2016 (UTC)
  • If the theory becomes widely accepted by the scientific community, it will be time to "update the textbooks". Not before. And the chances are slim.
History_of_special_relativity#Aether_and_electrodynamics_of_moving_bodies contains a whole lot of evidence against aether - if it exists, it should have zero local velocity in the reference frame of any object, yet create no measurable drag on them. So that is a viscosity-free fluid that still follows the objects, and that is extraordinary. Tigraan 15:25, 15 July 2016 (UTC)

Rabies vaccine "forbidden"?

Recently I got to familiarize myself with the relevant rules for transporting dogs internationally, including the rules regarding rabies vaccinations. I was surprised to learn that the country whose rules I was reviewing recognized three categories of dogs to consider:

  1. Dogs from countries where rabies is prevalent
  2. Dogs from countries declared rabies-free and rabies vaccine is available
  3. Dogs from countries declared rabies-free "that forbid rabies vaccinations"

In the third category, they gave examples of Australia and New Zealand. Why is there is a category of countries that "forbid" giving rabies vaccines to dogs? Is there actually something dangerous about the vaccine (e.g. a rare side effect, or something) that would justify not allowing the vaccine to be administered? Is it really true that Australia and New Zealand don't allow rabies vaccines, even for animals that will be traveling overseas? That seems very weird to me. Dragons flight (talk) 16:20, 14 July 2016 (UTC)

Australia recommends rabies vaccination for pets that might be exported and brought back. Assuming you could say you want to export the pet, then cancel the trip (which might just be overnight anyway, in theory), I don't think this can be a very strong ban, at least. Wnt (talk) 16:31, 14 July 2016 (UTC)
Usually such rules have to do with antibody tests to detect cases of infections not working anymore. In case of farm animals e.g., you cannot export animals if you vaccinate them against foot and mouth disease. This is why vaccination is only done when there is a major outbreak and an export ban is in place anyway. Count Iblis (talk) 16:35, 14 July 2016 (UTC)
Yes, for a human example, some countries where tuberculosis is not widespread don't routinely administer the tuberculosis vaccine, because anyone who has had the vaccine will test positive on the tuberculin test. See: Tuberculosis#Prevention. --71.110.8.102 (talk) 03:59, 15 July 2016 (UTC)
As with Wnt's point, these sources would seem to make it clear rabies vaccination for pets isn't forbidden in NZ, at least for export and pets travelling outside NZ. I'm not sure if the sources saying NZ forbids rabies vaccinations are just plain wrong, misleading or outdated as I can't find any info about NZ actually forbidding rabies vaccinations. It could be the vaccine was not formerly approved for use in NZ for whatever reason. It could also be rabies vaccinations are forbidden unless export or travel is a consideration although I personally doubt this. (Although I wouldn't be surprised if a vet were to get in trouble if they don't recommend against a rabies vaccination when there are no plans for travel or export.) It could also be because rabies vaccinations are rare enough that they are potentially something that needs to be specially ordered by most vets. (I'm not sure if this is the case even in most other rabies-free jurisdictions.) Nil Einne (talk) 17:29, 14 July 2016 (UTC)
It seems to me that we should be asking the OP where is this example of Australia and New Zealand forbidding rabies vaccinations? Let's see the evidence for that please. Akld guy (talk) 23:13, 14 July 2016 (UTC)
This might be relevant. --jpgordon 02:56, 15 July 2016 (UTC)
The OP never said said that NZ or Australia forbid rabies vaccinations but rather that sources gave them as examples of countries that forbid rabies vaccinations. They acknowledged that the examples may not be correct and I think we've already established the claim is questionable from Wnt's and my first response. See eg for the sort of sources the OP must be referring to. The websites all relate to Switzerland, although a bunch of spammy generic pet insurance websites also have the had the same thing. There is also one dead .nu web site I can't really understand with something similar although it seems to talk about needing proof they are forbidden and I have no idea where they were trying to export or take their pets to. Nil Einne (talk) 04:56, 15 July 2016 (UTC)
There is also which claims they are forbidden in Iceland. Nil Einne (talk) 05:01, 15 July 2016 (UTC)
I did not say that the OP said that Australia and NZ forbid rabies vaccinations. Geez, some people just love playing the game of semantics. Akld guy (talk) 06:15, 15 July 2016 (UTC)
Yes, this was in the context of Switzerland. Dragons flight (talk) 14:11, 15 July 2016 (UTC)

Wind strength of compressed air, part two

A few days ago I asked a question about the wind strength that would result from a sphere of air compressed from one kilometer in diameter to one-tenth of a meter in diameter. I was told that it would be as dense as a white dwarf, that oxygen-nitrogen fusion would result, and that the turbulence would require solving special equations. Really, what would happen if the force field that compresses the air were to shutdown in terms of interaction with the regular air? What would nitrogen-oxygen fusion look like? — Melab±1 ☎ 19:32, 14 July 2016 (UTC)

Here is The Synthesis of Elements from Carbon to Nickel, by astrophysicist Fred Hoyle. This paper series is considered the seminal work in the field, and it explains what fusion reactions are expected to occur under various extraordinary conditions. Well, these conditions are quite normal inside of stars - but they're very extraordinary here on earth!
Your hypothetical scenario is not exactly a physically-realistic condition, so you might have to be a little bit creative as you attempt to apply the results of well-established theories about stellar and supernova nuclear reactions. Nimur (talk) 20:51, 14 July 2016 (UTC)
O + O → S; O + N → P; N + N → Si; N + N → Si; N + N → Si; O + O → S; O + O → S; O + O → S; O + O → S; (there may also be reactions that yield unstable isotopes). Graeme Bartlett (talk) 03:54, 15 July 2016 (UTC)

July 15

Durian Fruit

I have smelt 'Durian' but it is too stinky. What may be the reason behind its stinkiness. — Preceding unsigned comment added by Sahil shrestha (talk • contribs) 02:48, 15 July 2016 (UTC)

See our article - Durian#Flavour and odour - my guess would be the sulfur compounds and the reason for the difference in perception being related to the asparagus urine smell (see asparagusic acid) where some people don't detect / smell the sulfur compounds produced by the metabolites. EdChem (talk) 03:39, 15 July 2016 (UTC)
An important odorant is 1,1-Ethanedithiol. Graeme Bartlett (talk) 03:56, 15 July 2016 (UTC)

Identify this bird

I saw this very large bird sitting on my neighbor's deck yesterday. In Northern California, San Francisco Bay Area. I thought it might be a turkey vulture but the head is whitish rather than red and the neck doesn't really look like a turkey vulture. It's also pretty bulky for a vulture, so I thought it might be a wild turkey, but it doesn't seem to have a wattle, and I've never heard of wild turkeys living in this area. Photos: CodeTalker (talk) 16:13, 15 July 2016 (UTC)

I suspect it is a turkey - though a juvenile so the wattle isn't yet fully developed. The distribution map shows that there is a population in northern California and Oregon. Wymspen (talk) 19:21, 15 July 2016 (UTC)
Yes, that is clearly a turkey. Matt Deres (talk) 20:14, 15 July 2016 (UTC)
I agree that it looks more like a turkey, but just for completeness, take a look at the turkey vulture. Doesn't look quite like your bird. StuRat (talk) 21:26, 15 July 2016 (UTC)
I know someone in Albany who often reports seeing turkeys; I'm not sure whether they're running wild or belong to some neighbor. —Tamfang (talk) 09:34, 16 July 2016 (UTC)
Or maybe they are just watching election news. :-) StuRat (talk) 17:49, 16 July 2016 (UTC)
  • Yup, t'is a turkey all right, you can't but not see Meleagris gallopavo back in my hometown (the northernmost in South Jersey), whether at dawn or dusk.
I could quit my job and lead tours, except everybody's at McDonalds or getting Pop-Eye's take-out that time of day.
These beasties've made such a comeback since the suburbs have replaced hunting the critters fer food it's downright dangerous.
Deer, raccoons, opossums, woodchucks have all literally exploded. (Mostly July 4th.) We even had that rabbit plague a few years back. They've crashed, but they're back too.
And here in NYC that have the rat clubs. Next it'll be flying lizards and freezing gorillers. Much of the US has greatly rewilded in the last century, and the commensals are doing just fine. Next it will be panders. In fact, my dad installed a cardinal=trup, although he's having a hard time finding will suet. μηδείς (talk) 04:24, 18 July 2016 (UTC)

Computer UV LEDs effects on the body and electronic components

I am playing around with a custom liquid cooling system, and plan to use UV reactive tubing. To have the glowing effect on the tubing, UV LEDs are required (for example). I am hestitate to order because of the questionable effects of UV on the body (skin & eye) and on the computer components. I don't have the exact model of the UV LED (maybe something like this), and don't think the manufacturer will list the specifications either. But I would like to have some basic guideline and advices, thanks.

Additional information: I will be using a case with full temper glass side panel, which provides no place to hide the UV LEDs. -- Livy (talk) 19:27, 15 July 2016 (UTC)

The effect of UV LEDs on skin is the same as that of sun light - tanning (unless you use UV-C LEDs). So, nothing to fear. Ruslik_Zero 19:49, 15 July 2016 (UTC)
Not really, since it's very well-established that UV exposure increases your risk of skin cancer. Tanning is a response to skin damage from UV light. I would avoid any unnecessary exposure to UV light sources. You'll survive without glowy tubes. (And incidentally, I think liquid cooling for computers is a waste of money, at least for personal computers, but hey, it's your money, not mine.) --71.110.8.102 (talk) 20:02, 15 July 2016 (UTC)
I know. It is mostly for aesthetic purpose. -- Livy (talk) 20:47, 15 July 2016 (UTC)
(edit conflict) Tanning... and cancer. But of course, the question is how much radiation will be received, and eyes are more fragile than skin anyways.
@Livy: Misplaced Pages does not give medical advice, so you will not get an answer to the question "is it safe to do X". You can start at Mercury-vapor_lamp#Ultraviolet_hazards, though I tend to think that UV LEDs will be less dangerous than spectral lamps. I think a PC-building forum would be the place to go for more specific info about how to build your system (where to put which part); if the UV source goes inside the case so that you only see the luminescence, I would assume it will be OK from a health perspective. Tigraan 20:10, 15 July 2016 (UTC)
I am not asking where to put the UV LEDs. I know it is best to keep them hidden. In this case, I am wondering if the tempered glass reduces the effect of UV by any chance. I know what to buy for my PC system and where to put them. It is not really a medical matter either I think -- I am not searching for a solution to my illness. I just want to know the short and long term effects of consumer UV LEDs on the body and on the electronic components (if any). -- Livy (talk) 20:47, 15 July 2016 (UTC)
Tempered glass will not significantly reduce UV flux at the wavelengths that consumer-grade UV LEDs typically operate (350-400 nm). Dragons flight (talk) 20:57, 15 July 2016 (UTC)
Also, you can determine this by experiment. Does a length of UV reactive tubing still glow when the glass is between it and the UV source? If yes, then the glass does not block UV. It isn't a perfect test, but it is better than nothing and easy to do. BTW, while we cannot give medical advice, we can certainly give engineering advice about whether long-term exposure to UV LEDS damage computer motherboards. I am guessing no but I would like to see a source. --Guy Macon (talk) 06:24, 16 July 2016 (UTC)
I am not sure that UV LEDs in in the 350-400 nm range would cause any significant risk of skin cancer, which is mainly related to the shorter UV-C and UV-B ranges. However I agree that they are not eye-safe. Ruslik_Zero 20:22, 16 July 2016 (UTC)
You might consider hooking the UV LEDs to a separate switch and then only turn them on for brief periods when you are showing off. Many fancy cases have switches built in for controlling LEDs. Dragons flight (talk) 06:43, 16 July 2016 (UTC)

July 16

Ionisation energies of actinides and lanthanides

I would have expected that the actinides would have lower ionisation energies than the lanthanides, since the 5f electrons would be further away from the nucleus than the 4f electrons of the lanthanides, and wouold be screened by more electrons. Furthermore, since only the first two lanthanides (Ce and Pr) can reach the oxidation state corresponding to the loss of all valence electrons (and Pr needs noble-gas matrix isolation conditions to do so), but the first five actinides can do it (Th, Pa, U, Np, and Pu, although only transiently for Pu), it would seem that the outer electrons of the early actinides are being held less firmly than those of the early lanthanides. Yet the list molar ionization energies of the elements on Misplaced Pages gives the opposite trend: Th has first ionisation energy 587 kJ/mol, while Ce has 534.4 kJ/mol, for example. Why is this so? Double sharp (talk) 14:16, 16 July 2016 (UTC)

In general, actinide behavior does not obey the periodic law as well as lower atomic number elements. That is, the trends predictable by an elements position on the periodic table break down by the time one gets to the actinides. Part of this is connected to the unpredictability of the electron configuration of actinides. Thorium for example has 6d2 7s2 while Protactinium is 5f2 6d1 7s2 and so on. --Jayron32 02:27, 17 July 2016 (UTC)

Adolescent

  1. Define, , , adolescent age group.
  2. What’s the correct word to use from “” stated above?

Apostle (talk) 18:38, 16 July 2016 (UTC)

Read Adolescence. ←Baseball Bugs carrots→ 19:29, 16 July 2016 (UTC)
"Pubescent" is often used in that context. The ages vary quite a bit, depending on sex, ethnicity, diet, and weight.StuRat (talk) 21:20, 16 July 2016 (UTC)
I Know, this is where the confusion is, I don't know whether I should use age numbers or the words specified in this post for my book. Any suggestion? -- Apostle (talk) 06:38, 17 July 2016 (UTC)
Choose whichever you prefer, define them clearly, and be consistent. Wymspen (talk) 10:58, 17 July 2016 (UTC)
Thats the problem, I have ESL issue. -- Apostle (talk) 04:58, 18 July 2016 (UTC)
Lol. -- Apostle (talk) 04:58, 18 July 2016 (UTC)

Creation and evolution in Russia

Of the approximately 145,000,000 residents of Russia, (a) how many believe that life was created by a supernatural intelligence, and (b) how many believe that life originated by spontaneous biogenesis and developed by macroevolution? (Also, how are those statistics distributed: by age, by sex, by subnational entity, by education, by occupation, and by religious status?)—Wavelength (talk) 23:13, 16 July 2016 (UTC)

Not as detailed as what you requested, but relevant: Creationism in Russia? Shock Brigade Harvester Boris (talk) 23:40, 16 July 2016 (UTC)

July 17

Physics curiosity

Suppose, I can move at the speed of sound. When a speaker speaks then simultaneously I also start to move at the direction of sound at the speed of the sound then what sound will I hear if the speaker has said "Hello"? and if I myself speak any word then will I be able to hear my own voice incase i move faster than sound? — Preceding unsigned comment added by Sahil shrestha (talk • contribs) 02:15, 17 July 2016 (UTC)

You won't hear the speaker, since you and the speaker's sound waves will be moving at the same speed. The sound waves need to hit your eardrums for you to hear them. Assuming you're inside a craft, you will be able to hear yourself just fine. There are myriad videos of people speaking just fine inside aircraft traveling at supersonic speeds. The thing to remember here is that speeds in general are relative to a frame of reference. If you run around inside an aircraft in flight, we don't consider you to be running at 100+ kilometers per hour, because we measure your speed relative to the body of the aircraft. The air inside the craft is being carried along with you, and it's at rest relative to you. (If we posit that you have superpowers and aren't flying in a craft, you might have trouble speaking due to the air barreling down your airway, though you'd need some secondary superpowers anyway to be able to breathe and not have your lungs explode, or to not require breathing.) --71.110.8.102 (talk) 06:23, 17 July 2016 (UTC)
Note that I interpreted the questioner's statement as "you move in the same direction as the speaker's sound waves", in other words, away from the speaker. Re-reading it, it seems unclear. --71.110.8.102 (talk) 06:28, 17 July 2016 (UTC)

You might be interested in the doppler effect. As you are moving away from the speaker, the apparent frequency of the sound he makes will get lower the faster you move away from him. When you reach the speed of sound, all aspects of the speaker's voice drop to a frequency of 0, and you can no longer hear anything at all from him. As for your own voice, well, that depends on what factors you want to include. As 71.110 mentioned, your exposed body were simply flung through the air at the speed of sound, you would be dead. If we ignore that, you'll just hear your voice normally through the vibrations in your skull, though that may be drowned out by the rushing air. If we ignore all of these factors, that depends on where the sound is generated relative to your ears. Sound moves at the speed of sound relative to the air itself, not the speed of the sound-maker. A super sonic jet, for instance, does not project any sound ahead of itself. It does project sound in the forward direction, but at the speed of sound relative to air, which it is outrunning. So if your sound is being made ahead of your ears, you will hear it doppler shifted to a very high frequency. If your sound is being made behind your ears, you will not hear a thing. Again, ignoring all these other little factors. Someguy1221 (talk) 06:35, 17 July 2016 (UTC)

@Sahil, the Good News is that you can move at the SoS (Speed of Sound) which is 343.2 m/s. Just stand at the Equator where you and everything around you are moving eastwards at 465.1 m/s. That's faster than you want, but knowing that the surface rotational speed is proportional to the cosine of the latitude you can reposition yourself north (or south) to latitude 44.45° (or minus 44.45°) to adjust your speed to the SoS. At least you could have done, had not astronomers discarded the geocentric in favour of the heliocentric system in which everything at the equator is moving at about 79000 m/s due to Earth's orbit around the Sun. So the Bad News is that makes it very difficult, short of a major investment in rocketry, to move as you suppose. See Orbital speed, Geocentric model and Heliocentrism. AllBestFaith (talk) 17:34, 17 July 2016 (UTC)
That doesn't really figure into it, as per the frame-of-reference cited earlier. If you are standing next to someone, your speed relative to the center of the earth, the solar system, the galaxy, etc. don't matter. Compared to each other, you're standing still. ←Baseball Bugs carrots→ 17:57, 17 July 2016 (UTC)

Why is the UK and US building different trident-armed submarines?

America is building the Ohio Replacement Submarine while Britain is building the Successor-class submarine. Both will cost around 7 billion each and they'll start to enter service in 2028/2031. Can anybody tell me the difference between them in terms of engineering/specs? Also, while not a science question, does anybody know why both countries aren't building the same? It'd be cheaper that way. 2.103.15.147 (talk) 02:30, 17 July 2016 (UTC)

Here is a free report available to the public from the RAND Corporation, a very famous American organization that has had very strong historical ties to the nuclear policy decision-makers in the United States government: The British Nuclear Deterrent After the Cold War (1995). It's a good overview that explains why things are the way things are. There is a lot of politics behind the American/British Trident nuclear missile program, so this report will help give you some background. And here is a 1984 report, British Nuclear Policy-Making.
Directly addressing the "costs" of the submarines: the author Nicolas Witney of the Ministry of Defence eloquently phrases it, in pleasant British English, "...such sums, though by no means trivial, do not weigh heavily when set set against the sunk costs and the importance long ascribed by successive British governments to the strategic deterrent." Or as I say it, in my brasher American idiolect, when we're talking about blowing up the planet, "money" ceases to have any meaningful economic implication.
Here is a well-cited article from the Fall 2003 RAND Review: Excessive Force: Why Russian and U.S. Nuclear Postures Perpetuate Cold War Risks.
Britain's choice to deploy an American-made nuclear weapon on a British-made nuclear submarine is rooted in their government's perceived need for their nation to have independent control of the nuclear arsenal, while satisfying domestic political concerns that preclude them from independently designing a nuclear weapon.
This 2007 book, part of the RAND Monograph series, Sustaining U.S. Nuclear Submarine Design Capabilities, defends the position that it is necessary for a nuclear-weapon-state to design a nuclear submarine fairly frequently to ensure that critical institutional knowledge and skills are preserved, in case that knowledge, skill-set, and engineering infrastructure is ever needed in the future. Surely, the decision-makers in the British government consider the very same issue.
Nimur (talk) 03:41, 17 July 2016 (UTC)
Here's a great resource from Royal United Services Institute - sort of a British counterpart to RAND: Continuous At-Sea Deterrence: Costs and Alternatives. In this report, there is considerable discussion (based on the theory of nuclear deterrence, which is another topic worth reading about). On this topic, it is claimed that Britain cannot cease its continuously-available nuclear deterrence unless both the United States and Russia make significant policy-changes. Ultimately - and this is a sinister conclusion that is very extensively studied - the UK cannot trust the Americans as an ally unless the UK maintains the credible capability to independently annihilate the Americans. Our article on the so-called security dilemma has some references on the topic of uneasy alliances in nuclear strategy theory. If you read extensively on the topic of why we even have nuclear submarines - particularly, with respect to the role nuclear submarines play in the theory of second strike capability, you'll find that this theme recurs very frequently. Nimur (talk) 03:55, 17 July 2016 (UTC)
It should not be a matter for surprise that the British do not trust Donald Trump. In a worst-case scenario it might even be a matter of relief to the US public that Britain has something purporting to be an independent weapon that might deter. Unfortunately, by that time, Trump will know that he has an override. Thincat (talk) 13:48, 17 July 2016 (UTC)
The difference is that one is a pointless porkbarrel for local jobs in the US, the other is an even more pointless porkbarrel for jobs in the UK. In a part of the UK which might not even be in the UK for much longer. Andy Dingley (talk) 14:38, 17 July 2016 (UTC)
Actually very little pork for Scotland, but a lot for Barrow-in-Furness. Assuming you're not envisaging an independent Cumbria. Henry 16:48, 17 July 2016 (UTC)
The UK ones are built in England, but based in Scotland - so that does create jobs in both areas. Wymspen (talk) 17:27, 17 July 2016 (UTC)

conical pendulum -Referencedesk Archives/Science2016May31

If we disregard the force to start and maintain constant movement of a conical pendulum, are there any practical(scientific/commercial) purposes to which the force generated /the movement created can be utilised. Eg electrical generation in remote areas. Assume a small pendulum length of say 600mm.139.216.164.174 (talk) 21:03, 17 July 2016 (UTC)

Any attempt to extract work from the pendulum will quickly cause it to stop swinging. As you were told back in May, there is no such thing as a perpetual motion machine, and you can't get energy for free. Rojomoke (talk) 21:32, 17 July 2016 (UTC)

Dogs protecting humans

There are many stories about dogs protecting humans, sometimes sacrificing themselves. This is very unusual; few animals will die for non-relatives. How much has this behavior been studied? 69.22.242.15 (talk) 22:03, 17 July 2016 (UTC)

Well, while the origin of the domestic dog is complex, they are definitely related to wolves, and some of those have an alpha pair that mate and produce offspring, while the rest of the pack does not breed. The rest of the pack are related to the alpha pair, though, so the best chance to pass on their genes may be to protect the alpha pair, even if they themselves die. Since humans often take on the role of "alphas" in their relationship with dogs, this instinct may continue, even if it no longer is biologically "logical". StuRat (talk) 22:34, 17 July 2016 (UTC)
Even with children: In separate rattlesnake attacks, dog saves child and child saves dog. μηδείς (talk) 23:19, 17 July 2016 (UTC)

Cats protecting humans?

Inspired by the thread above. Why would a cat protect a human child from a dog attack? I thought that cats generally didn't care about anyone other than themselves?

Vid:

https://www.youtube.com/watch?v=aBW5dfRoG7Q

--146.90.107.28 (talk) 23:28, 17 July 2016 (UTC)

Cats care about their kittens and that mechanism is easily displaced (for lack of a better term) toward human family. Most interactions between humans and domestic cats can be explained in terms of parent-child relationships. Ian.thomson (talk) 23:31, 17 July 2016 (UTC)
Yes, I've heard that the behavior of bringing live (but wounded) mice/birds/frogs to humans to finish off can be a manifestation of that. --146.90.107.28 (talk) 23:42, 17 July 2016 (UTC)
I'm a little dubious about the video, which is shot from two different viewpoints which just happen to be perfect to capture all the action. Staged? {The poster formerly known as 87.81.230.195} 2.123.26.60 (talk) 00:51, 18 July 2016 (UTC)

SAS snipers training to shoot the engine blocks of speeding trucks?

Just been talking to my father about this story in the paper today concerning SAS snipers training to stop a potential terrorist truck attack in the UK, similar to the Nice atrocity.

What manner of weapon/ammunition would they use for this, do you think? The Barret M82 firing tungsten-tipped rounds? I know there's a lot of myths about 'shooting through the engine block' (I know that a .44 magnum pistol can't actually do this, despite the pop culture thing). --146.90.107.28 (talk) 23:40, 17 July 2016 (UTC)

I have not been able to find any military sources detailing what they expect their .50 armor piercing rounds to actual do, and what soldiers are trained to do. But you can easily find a ton of videos on youtube of people shooting engine blocks with .50 rounds of various types to see what happens. One video does show a running truck engine stop after being hit by a .50 armor piercing round . Someguy1221 (talk) 01:05, 18 July 2016 (UTC)
It's worth noting that the Daily Hate story is, for the most part, confected bullshit, even down to their reuse of a 2013 photo of a sniper completely unrelated to the SAS. --Tagishsimon (talk) 01:11, 18 July 2016 (UTC)
And WHICH parts of the story, exactly, ARE fabricated??? 2601:646:8E01:7E0B:258A:F94:7EFA:6739 (talk) 02:01, 18 July 2016 (UTC)
If you have that kind of firepower, I should think killing the driver would be the more effective way to stop a truck. StuRat (talk) 01:15, 18 July 2016 (UTC)
I wasn't aware that SAS had branched out into weaponry. ←Baseball Bugs carrots→ 01:44, 18 July 2016 (UTC)
great joke, my sides! lol! 90.63.167.63 (talk) 02:19, 18 July 2016 (UTC)

July 18

Roughly how many people may have been alive during the last glacial maximum?

Just like the headline, I'd like to know if there is any estimate as to how many people (in the world) may have been alive during the last ice age. My guess is about 500,000, but I could be way off. I would accept an estimate for any point of the last ice age. I'm not picky! Thanks! Lighthead 00:47, 18 July 2016 (UTC)

It has been recently estimated that the human population reached a minimum size of 130,000 individuals during the LGM, but this is highly speculative . The field of paleodemography has attempted to produce estimates based on genetic and archaeological data, but this gets more speculative going further back (with people often doubting any estimates prior to 10,000 BCE), and the genetics is limited in that it can only produce estimates of the number of people at a given time who have currently living ancestors (though you can then estimate based on simulations how many people there were total). Someguy1221 (talk) 00:57, 18 July 2016 (UTC)
Note this estimate is only for the population of Europe. World_population#Past_population gives a global population estimate of 4 million at 10,000 BCE which was around the time that temperatures reached near-current values after the last glacial maximum. The same article gives an estimate of <15,000 at 70,000 BCE, when ice sheets had reached near maximum following the onset of glaciation. As Someguy1221 points out all of these estimates need to be taken with a few grains of salt, or a whole shaker-full.
There's a nice figure here comparing δO (an indication of glacial ice volume) to prehistoric human activity. Shock Brigade Harvester Boris (talk) 02:48, 18 July 2016 (UTC)

Paleodemography is the go-to article. Technically, of course, we are currently still in an interglacial period of the Quaternary glaciation, but I guess you probably mean the Last glacial period, which has different names in different localities and ended about 12,000 years ago. {The poster formerly known as 87.81.230.195} 2.123.26.60 (talk) 01:02, 18 July 2016 (UTC)

Thanks for all the responses! Lighthead 02:58, 18 July 2016 (UTC)
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