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November 2

What led to the increase in prevalence of breastfeeding?

According to this, https://en.wikipedia.org/wiki/History_and_culture_of_breastfeeding starting in the 1960s there was a resurgence in breastfeeding in United States and Canada.What caused the resurgence? — Preceding unsigned comment added by 2001:569:7733:AD00:AD6F:C935:4788:3388 (talk) 07:54, 2 November 2017 (UTC)[reply]

This paper, which was the first result when I typed "cause of resurgence of breastfeeding" into google, as seen here looks to have a good start to you research, as it not only has a wealth of information on its own, itself links to dozens of other studies on the matter. --Jayron 32 10:51, 2 November 2017 (UTC)[reply]

The OPs cited article notes that "By the 1950s, the predominant attitude to breastfeeding was that it was something practiced by the uneducated and those of lower classes. The practice was considered old-fashioned and "a little disgusting" for those who could not afford Infant formula and discouraged by medical practitioners and media of the time. By the 1960s the touted suitability of infant formula as a substitute for human milk was being questioned, which lead later to warnings such as "lack of breastfeeding—and especially lack of exclusive breastfeeding during the first half-year of life—are important risk factors for infant and childhood morbidity and mortality" (WHO 2003) and "a formula-fed child living in unclean conditions is between 6 and 25 times more likely to die of diarrhea and four times more likely to die of pneumonia than a breastfed child." (UNICEF 2007). Blooteuth (talk) 14:20, 2 November 2017 (UTC)[reply]

Benjamin Spock's The Common Sense Book of Baby and Child Care in 1946 was shown on I Love Lucy 1951-1957.
Sleigh (talk) 10:07, 7 November 2017 (UTC)[reply]

November 3

Tesla coils

Can Tesla coils be used as weapons on the battlefield, and if so, are there real-life examples of this (either in development or actually deployed)? 2601:646:8E01:7E0B:B9F4:7CD7:EC0A:69F7 (talk) 04:22, 3 November 2017 (UTC)[reply]

No, and no. Edison (talk) 05:48, 3 November 2017 (UTC)[reply]

Regarding the first question, why not? 2601:646:8E01:7E0B:B9F4:7CD7:EC0A:69F7 (talk) 06:26, 3 November 2017 (UTC)[reply]

Well, This dude actually built a portable, wearable Tesla coil gun, but it seems to lack any sort of real-world battlefield application, other than looking a bit scary. I'm quite certain that if it could be made into a usable weapon, somebody would have done it by now. Alansplodge (talk) 10:51, 3 November 2017 (UTC)[reply]

Slapping with a haddock could be used as a weapon, but the real question is whether it would be effective. A Tesla coil is fragile, power hungry and not terribly damaging. The best defence against them is some sort of tin hat or tin box to sit in, both of which are widely used by the opposing forces.

Also a Tesla coil is largely omnidirectional, meaning that it acts in all directions (your troops too), wastes energy in being effective in a direction where your enemy isn't, and makes it susceptible to the inverse square law, so seriously range limited.

Any sort of battlefield directed energy weapon needs to be just that: directed. It needs to put its energy in one direction, towards the enemy and them alone. This may also reduce the inverse square law effect (but look at far field and Fraunhofer beam for why lasers don't work how you probably think). Andy Dingley (talk) 10:56, 3 November 2017 (UTC)[reply]

Would that make this a war crime then? --Jayron 32 13:39, 3 November 2017 (UTC)[reply]

No, but it might be tench warfare. Andy Dingley (talk) 18:41, 3 November 2017 (UTC)[reply]

Are we allowed to give military advice? What happens if someone loses a whole war because of reliance on it? Will they sue the Foundation? --Trovatore (talk) 19:02, 3 November 2017 (UTC) [reply]

Don't worry about them. The Mule will eventually mess up their work. All roads lead to Trantor and that's where all stars end. --Jayron 32 02:51, 4 November 2017 (UTC)[reply]

I should point out that railguns have military application. However, those use pulsed DC rather than alternating current, which excludes them technically and spiritually from all things Tesla. Wnt (talk) 19:09, 3 November 2017 (UTC)[reply]

[un-indent] Thanks, all! So, the reason why they're not used in war is because they're inefficient, indiscriminate, and (contrary to what the folks at Westwood would have you believe) are completely ineffective against armor? 2601:646:8E01:7E0B:0:0:0:EA04 (talk) 09:20, 9 November 2017 (UTC)[reply]

Technical Problem

Has any body noticed that it is just not possible to download the first pic in article Railgun in it's highest resolution? Why is it so ? RF regulars are kindly requested to pass it on to the appropriate Wikipedia people if it's a technical bug (as I don't know how to reach them, please) 124.253.7.215 (talk) 21:23, 3 November 2017 (UTC)[reply]

File:Railgun usnavy 2008.jpg worked for me just now, both via the "Original file" link on the image description page and via the "Download original file" item after clicking the download link in the media-viewer mode. Firefox-56.0.2. How exactly are you trying it? DMacks (talk) 21:34, 3 November 2017 (UTC)[reply]

Enabling works for new railway lines

Do enabling works for brand new railway lines such as demolition, utility and infrastructure diversions etc fall under railway civil engineering? Some people argue that it’s not railway civil engineering and is just general civil engineering. Clover345 (talk) 11:35, 3 November 2017 (UTC)[reply]

Civil engineering is a widely-recognized (perhaps the most widely-recognized) major engineering discipline. "Railway civil engineering" is not, though it seems like a useful subset or sub-discipline. As such, virtually everything that might plausibly fall under "railway civil engineering" will also fall under the banner of civil engineering (whether prefaced with "general" or not). — Lomn 13:28, 3 November 2017 (UTC)[reply]

General civil engineering. For example, if a major water line needs to be moved it doesn't really need a railway civil engineer. A cantilever rail bridge (with a speed rating of x) spanning a gorge is a different story. 196.213.35.146 (talk) 13:30, 3 November 2017 (UTC)[reply]

I wouldn't hire a railway engineering firm to design and build a bridge (and I probably wouldn't go to an advertising "general" firm, either). I'd go to a firm that does bridges. Which, I think, illustrates nicely that the proposed division isn't universal or clean. An engineer with rail specialization would need to provide input on either the water line or the bridge (What's the maximum weight on the line? How deep does the line construction itself go? What's the maximum grade permissible on or near the bridge? What about turning radius?) but likely would not have the specialist knowledge to design either the water line or the bridge itself. Conversely, the engineer responsible for either of those projects would likely not have the specialist knowledge to derive the rail-applicable requirements that impact the designs (or for a great many other requirements). Engineering work of any substantial magnitude is not a single-subdiscipline affair. — Lomn 14:18, 3 November 2017 (UTC)[reply]

(ec) In part, the answer probably depends on why you're asking—there may be jurisdiction-specific situations that have explicit legal/regulatory definitions and requirements as to what constitutes "railway" civil engineering. One might also be taking a university course where the instructor has a particular and specific definition in mind. The question could come up in dealing with a professional organization that has particular requirements for membership.

The first relevant Google hit I get is for the UK's Railway Civil Engineer's Association, which says "Railway engineering is an engineering discipline that deals with the design, construction and operation of railway systems." For membership, their criteria include:

"Those who are engaged in, or been engaged in, the development, design, construction or maintenance of engineering infrastructure for railway operations. Ordinary members will normally be professional engineers. ..."

There's some wiggle room there, but I would tend to interpret those in a manner akin to that suggested by 196.213 above. A railway engineer would determine the location and design of the new line, and would likely be involved in identifying required demolition projects and utility relocations. Once those requirements were specified, however, it would not necessarily require railway-specific knowledge or training to carry them out; they're not railway engineering. If a sewer pipe needs to be relocated to allow the construction of bridge footings, it doesn't matter if the bride is for road or rail use—the pipe just needs to be somewhere else.

Indeed, substantial demolition or utility relocation projects would likely require their own flavors of engineering experts, with specific training and qualifications that a railway engineer wouldn't be expected to have and wouldn't be permitted to sign off on. On a major project, I would expect multiple different types of engineers to collaborate. And I am sure that there are some blurry edges associated with some tasks, as well. Honestly, your best bet might well be to contact organizations like the RCEA directly, and just ask them how they handle this question. TenOfAllTrades(talk) 14:39, 3 November 2017 (UTC)[reply]

Interesting. But surely there are some significant differences between a railway bridge and a road bridge as they will be subject to different types of loading. Clover345 (talk) 14:47, 3 November 2017 (UTC)[reply]

See [1]. This [2] shows how the two disciplines interact. At Upper Holloway, for example, the bridge carrying the main road from London to the north had to be reconstructed and various utilities relocated. 80.5.88.70 (talk) 15:47, 3 November 2017 (UTC)[reply]

Yes, there can be significant differences also in aesthetics, budget and whether there is a pre-existing foundation. The article Bridge gives an introduction to the many options available to the project engineer who needs to have expertise about the failures of bridges that first assumed national interest during the Victorian era when many new designs were being built, often using new materials. Blooteuth (talk) 16:53, 3 November 2017 (UTC)[reply]

Is it more common to classify civil engineers as infrastructure civil engineers or buildings civil engineers? Clover345 (talk) 17:47, 3 November 2017 (UTC)[reply]

Here are current examples of recruiters for both Civil Infrastructure Engineer and Buildings – Civil Engineer. Blooteuth (talk) 19:04, 3 November 2017 (UTC)[reply]

X-rays

1.As we know that most typical digital cameras (likes the ones in smartphones etc.), are able to detect infrared rays, unlike human eyes are (except in very rare cases). Are these typical digital cameras like the ones in our mobiles, or our DSLRs etc. also able to catch X-rays (let's, for sake of simplicity, limit the question to the X-rays that are produced by the machines used to look into the human-body in medical diagnosis works).

2. I have read somewhere that if the simple task of detaching the adhesive cellophane tape from it's roll, is done in strong vaccum, X-rays are produced ! Is that a fact or a myth ? Jon Ascton (talk) 20:10, 3 November 2017 (UTC)[reply]

Theoretically hard X-rays hitting a CCD will cause flashes of light, which can be detected. However the camera optics does not work for X-rays. So, X-rays coming from any direction will be detected - the camera will not display any X-ray image. Ruslik_Zero 20:26, 3 November 2017 (UTC)[reply]

The scotch-tape thing is real. here are researchers from UCLA actually imaging someone's finger bones this way! ApLundell (talk) 21:01, 3 November 2017 (UTC)[reply]

this article suggests that a ccd from an ordinary digital camera would be a poor way to detect gamma rays, but this article talks about an East Hartford company that proves it can be done, at least if the source is dangerously powerful. Neither are these are about the precise frequency of gamma waves that make up medical x-rays, but they may be close enough for your purpose. Ruslik0 is correct that in both cases, since x-rays will pass straight through the optics (and everything else), you won't get an image as much as you'll get random static. ApLundell (talk) 21:22, 3 November 2017 (UTC)[reply]

Related : If you've ever watched any of the videos coming from the space station, you'll know that all their DSLRs have bad pixels. Gamma Rays.

ApLundell (talk) 21:23, 3 November 2017 (UTC)[reply]

The semiconductor elements of the CCD array are affected by X-rays, so they will "detect" them as in the above responses. However, all of the rest of the semiconductor elements in the camera are also affected by X-rays at least to some extent, so enough X-rays to register on the CCD as a bloom may also be enough X-rays to produce a soft error while the camera tries to process the image, resulting in anything from a tiny glitch, to loss of the image, to a latch-up requiring the camera to be powered off and back on. A very large dose of X-rays can result in damage rendering the camera unusable.-Arch dude (talk) 23:15, 3 November 2017 (UTC)[reply]

There are a few phone apps that use the builtin CCD camera as a gamma/x-ray detector.[3] DMacks (talk) 18:53, 4 November 2017 (UTC)[reply]

Namibia "hammocks"

The article on Namibia says "Near the coast there are areas where the dunes are vegetated with hammocks", linking hammock (ecology). The source linked to [4] currently consists of the words "index.php". The article on hammocks lists a number of different things in Florida -- there are xeric hammocks [5], but these are wet, surrounded by well-drained sandy soil. By contrast, the article on Namibia describes the entire country as arid or semi-arid. Stupid searches get nothing but photos of tourists, obviously; "xeric hammocks" and Namibia turns up nothing much. Your mission: figure out if there are really (ecological) hammocks in Namibia, what kind they are, whether they are in some special foggy microclimate that is not arid so that it is actually too wet around them for trees like in Florida. Wnt (talk) 23:12, 3 November 2017 (UTC)[reply]

The coast of Namibia is known for its significantly different climate to inland. The Atlantic coast of Southern Africa has much colder currents than the Indian Ocean coast and this leads to the famous cold fogs of coastal Namibia. Although these lead to some rainfall, notable itself in this largely arid climate, they also produce significant precipitation as dew on plots of coastal vegetation. So the vegetated plots (whatever they're called, I'm unfamiliar with hammocks) become self-sustaining. Andy Dingley (talk) 23:41, 3 November 2017 (UTC)[reply]

Thanks to the Wayback Machine, Here's that source article as it appeared in March 2016. The word "hammock" does not appear, but "hummock" does (and the article hammock (ecology) suggests that the one derives from the other). The relevant sentence is "Vegetated dune-hummock areas are common near the coast", but I don't know if it's correct to interpret that as meaning hammocks. --69.159.60.147 (talk) 04:44, 4 November 2017 (UTC)[reply]

The distinction between a hummock and a hammock is subtle. One is an slightly elevated coastal area with woody vegetation. The other is a high mound near the sea with trees. Most importantly for our discussion, one has a "u" in it, while of absolute importance to settling the dispute, the other has an "a". As to which applies to the coast of Namibia, I'm not entirely sure. Perhaps choosing a third term which is more universal may be useful. --Jayron 32 04:59, 4 November 2017 (UTC)[reply]

... and etymologists seem unclear and not in agreement about whether or not one word was derived from the other in the sixteenth century. I agree that choosing a more world-wide term would be more appropriate for this area and this article. Dbfirs 08:43, 4 November 2017 (UTC)[reply]

The "dune-hummock" tip is highly informative -- dune hummocks = nabkhas are well known in coastal areas around the world; their anchoring by bushes in Finland is described, for example. [6] There are a number of single hummocks visible as images, though this photo suggests the hummocks can be densely packed in larger areas. This link suggests a more specific location and suggests the mist is salty. There is a lot of information about Namibian dunes overall [7] but I'm still a bit unclear whether the dune-hummocks are classified in any higher-level unit than the single little hump. Wnt (talk) 11:40, 4 November 2017 (UTC)[reply]

Hey User:Wnt, I'm confused about what you're unclear on. Out side of the slightly more specific sense described in our article, hammocks are generally just raised bits of vegetation; often there is some interesting process that forms them. I don't think there's anything intrinsic/necessary about moisture, but often they have something distinct going on ecologically, behaving as relatively isolated communities, often centered around a few sort of ecosystem engineer species that provide refugia or food etc. I am not terribly familiar with hammocks in Namibia, but e.g. here [8] they are clearly referred to as hammocks, though I can't figure out what they mean by "nama plants", except that I'm pretty sure it's not nama_(plant), as that is a new world genus. I think it might be a garbling of the plant called "!Nara" in the Nama language, Acanthosicyos_horridus, which is endemic to Namibia and provides a mechanism for dune/hammock building as described here [9]. Sometimes, when speaking of hammocks, the word can mean either one specific hammock, but it can also be used to stand for the set of all of them in the region. E.g. "a hammock species", or "the hammock [ecology/community/system]." Does that help at all? SemanticMantis (talk) 19:05, 4 November 2017 (UTC)[reply]

@SemanticMantis: Our article describes the hammocks as stands of trees, while the dune hummocks I was looking at in our other article are individual bushes anchoring a mound a few meters in size. The source you cited is useful - I ran down its source at a doctoral thesis online [10] which says "The characteristic plant at the study site is Acanthosicyos horridus, the nara, a member of the Cucurbitaceae, and an endemic of the Namib sand dunes. The species grows in the dune valleys were there is access to underground water." The thesis uses the word "nara" a bazillion times, so indeed the other source was in error. Crucially, it explains (p. 16) that "Nara plants form dense, tangled bushes and as sand is trapped underneath the branches, a hummock reaching considerable size is built up. These hummocks can reach sizes up to 4m in height and cover an area of up to 1000 m2, forming micro-ecosystems within the dunes of the Namib Desert." So bushes not trees, centered on underground water rather than avoiding it, but also a large formation; I'm not sure now which is larger. In short, although you weren't sure how I was unsure, you led me to the exact thing to explain what I was unsure about. ;) Now I just have to figure how to bring this back to the article. Wnt (talk) 23:20, 4 November 2017 (UTC)[reply]

Cool, good job sorting it out. My two cents is that it hardly matters to maintain any distinction between hammocks and hummocks, they are both just raised bits of vegetation that have something interesting about them. I once saw a fascinating talk about how topography influences plant competition. Guy put up a map that looked like a range of rolling hills, showed how elevation had strong effects on species filtering, then revealed the punch line of the scale: the peaks were just a few cm high. Anyway, he called them hammocks, as I recall :) microtopography is a redlink, but you can find plenty of research on the topic using that keyword, and some of it highly relevant to the concept of hammock/hummock. SemanticMantis (talk) 17:27, 5 November 2017 (UTC)[reply]

In "What is a hammock?" I find "In the Everglades a hammock refers to 'isolated patches of small broadleaf trees, many of them West Indian species, in the sawgrass or maidencane marsh or limestone pinelands'." Bus stop (talk) 17:39, 5 November 2017 (UTC)[reply]

That's a nice clear definition, but it only applies to the Everglades, and does not cover general usage in plant community ecology. So it's not going to apply to the hammocks that are raised isolated patches of endemic cucurbits in Namibia. SemanticMantis (talk) 15:32, 6 November 2017 (UTC)[reply]

We also have the article Hummock. Admittedly it is hardly perfectly on target, vis-a-vis the question asked, but I just thought I would bring it to everyone's attention. Bus stop (talk) 21:24, 6 November 2017 (UTC)[reply]

November 4

Star in Cancer named for Marina Popovich

Marina Popovich says that a star in Cancer is named after her, but the reference is in Russian and it doesn't come up for me. Which star is it? (List of stars in Cancer doesn't list those types of names.) Bubba73 ^{You talkin' to me?} 05:24, 4 November 2017 (UTC)[reply]

Very few stars are officially named after individuals. See IAU Working Group on Star Names, and note that the lists linked from that article's references do not include the names "marina" or "popovich". So this seems unlikely. (Note, there are companies that sell the right to "name" a star but nobody else recognizes those names. See Stellar designation#Sale of star names by non-scientific entities.) --69.159.60.147 (talk) 09:18, 4 November 2017 (UTC)[reply]

Cancer is her Sun sign (90 to 120 degrees ecliptic longitude). Sun in International Astronomical Union Cancer after 8:41pm UTC+3. Sagittarian Milky Way (talk) 12:57, 4 November 2017 (UTC)[reply]

That reference is dead. Ruslik_Zero 20:39, 4 November 2017 (UTC)[reply]

This here says it's Alpha Cancri (last para), and it was Gherman Titov who gifted her the certificate to the effect. However, as has been noted, unlike comets, say, stars are never officially named after people, not that it keeps shady companies from selling the stuff. 78.53.24.148 (talk) 21:21, 4 November 2017 (UTC)[reply]

That's what I was going to say, but then I looked at the references (cited above). Very few stars are officially named after individuals, but "never" is now wrong. The longstanding nickname Barnard's Star is now an official name, for example. --69.159.60.147 (talk) 04:24, 5 November 2017 (UTC)[reply]

Thanks, I thought that it probably wansn't official. Bubba73 ^{You talkin' to me?} 02:42, 5 November 2017 (UTC)[reply]

Resolved

(Simply because it hasn't been linked yet) Stars named after people does list a few more besides Barnard's Star. Some, such as 61 Cygni aka 'Bessel's Star', do have different official names, but there are other examples (e.g. Kapteyn's Star). Marina Popovich is not on that list, nor is she mentioned in the subsection "Covertly named stars". ---Sluzzelin talk 05:28, 5 November 2017 (UTC)[reply]

Most comets are named after people, and so are some asteroids 45 Eugenia. 86.155.148.59 (talk) 16:00, 5 November 2017 (UTC)[reply]

Stars with naked eye

I couldn't figure out how to word it properly with Google but my question is: I see a lot of amazing pictures of galaxies and stars and cosmic dust and all that, but how much of that is actually visible to the naked eye? I am planning to take a trip to a place with little to no light pollution and I'm trying to temper my expectations. Thank you! — Preceding unsigned comment added by 80.6.102.227 (talk) 22:21, 4 November 2017 (UTC)[reply]

See Bortle scale for examples of astronomical objects visible with the naked eye at various levels of light pollution. The Naked eye article may also be useful. Tevildo (talk) 22:28, 4 November 2017 (UTC)[reply]

As Bortle himself explains here, you need to get quite far away from big cities, light reflects back from the atmosphere, making the sky even 100 km away from a city become very slightly gray. While you can then see many faint stars, nebulae with low surface brightness will still be drowned out. E.g. in Western Europe, you won't be able to easily see the Triangulum Galaxy with the naked eye, it may be possible to see with a lot of effort from the Alps. This is because it's hardly possible to get away more than a few hundred km from a large city like London, Paris, Brussels, Berlin etc. etc. in Western Europe. Ideally you need to be 1000 km away from such big cities, then you should be able to easily spot such faint objects like the Triangulum Galaxy. It is from such places where you can spot even fainter object with effort, e.g. the astronomer Brian A. Skiff has seen the galaxy M 81 with the naked eye as he mentions here. But he failed to spot Neptune with the naked eye, even though it is theoretically possible to do so. Count Iblis (talk) 00:34, 5 November 2017 (UTC)[reply]

The less lightpollution the better ofcourse but actually the weather is much more important since without a clear sky, without any lightpollution, you would only have a "lightunpolluted" view on the clouds. --Kharon (talk) 01:59, 5 November 2017 (UTC)[reply]

You don't need 1,000 kilometers. Maybe in space or in an airplane when you can see further but from sea level look at the light pollution map of the ocean near New York or Tokyo. If you need 1,000 kilometers somewhere it's because of closer cities, suburbs or farms, not because of your city (also light fishing and human and natural fires can cause enough light to cause light pollution. I haven't done the math to see if there's enough air in the volume lit enough by a candle for things that small to cause it too but if it could it'd only have inches or feet of range. You'd also have to avoid seeing the candle or anything lit brightly by it for 30 minutes to adapt your eyes to the dark before you could test this. [You can look at a candle from less than 1,000 feet away without affecting your dark adaption] so it's got to be much closer if the air around that light is glowing enough from scattering to affect the view) Sagittarian Milky Way (talk) 05:52, 5 November 2017 (UTC)[reply]

Photographs of the less bright astronomical objects usually show too little (especially film without a bulb setting) or too much (i.e. taken in space, infrared, composites of long exposures, sometimes including black and white frames through a filter that blocks all but the tiny fraction of the rainbow nebulae glow in (which are then colored i.e. hydrogen red in software, nebulae can be seen with the naked eye but they're gray and usually smaller)) Infrared's pretty neat. The naked eye Milky Way looks brighter the closer to the center it is (both centerline and center point) except a rift of dust seems to block what would be some bright-ass stuff. And it is, Milky Way dust is amazing. 1,000 light years doesn't dim much but 50,000 light years towards the far side of the galaxy dims 100,000,000,000,000,000,000 times. The redder the light or infrared the picture is taken in the further into this dust you can see. Also most stars are brighter in infrared than any color of light. There's a star barely visible to the naked eye that's the 3rd brightest star in the sky in near-infrared. It's a class above Sirius in any color of light but it's just too red for humans. Sagittarian Milky Way (talk) 05:34, 5 November 2017 (UTC)[reply]

The user geolocates to Dunstable, UK. In New Jersey one can go to the New Jersey Pine Barrens, Batsto, New Jersey being a good place to stop right off the road in a public field, and see the Milky Way and a very bright starry sky on clear, moonless nights. But in the Northern Hemisphere galaxies appear at best as star-sized nebulae to the naked eye. The Andromeda Galaxy, the closest non-dwarf galaxy to ours is in the Southern Hemisphere. μηδείς (talk) 02:30, 5 November 2017 (UTC)[reply]

That location isn't too similar to what the darkest possible looks like really. It's only dark by New Jersey and Philly area standards. The closest land you can't detect light pollution with the naked eye from if you know what to look for might be Canada. Sagittarian Milky Way (talk) 04:08, 5 November 2017 (UTC)[reply]

Your one-upmanship is not particularly helpful, SMW. The Pine Barrons cover 1.1 million acres (4,500 km2; 1,700 sq mi), some 22% of New Jersey's land area, and comparing the land pictured to Philadelphia is simply ridiculous. I might as well say that the heights of the Andes or the Himalayas are better than Saskatchewan for star-watching, and then of course there's Earth orbit or the dark-side of the moon. I simply noted an easily-accessible area between Philadelphia and NYC where one can indeed see things like the Milky Way and the Orion Nebula. μηδείς (talk) 23:53, 5 November 2017 (UTC)[reply]

Above 3 kilometers only helps if you stargaze with oxygen bottles cause dark adaptation's one of the first things to go. I guess astrophotography would still work till the height you forgot how to use a camera. Sagittarian Milky Way (talk) 09:39, 7 November 2017 (UTC)[reply]

File:Northeasthsalpmap.jpg

This is why I mentioned they're only dark by Jersey and Philly metro (5000 mi²) standards. The Pinelands are a great resource for everyone in the marked area but if someone's coming all the way from England they should know that they're not that dark by North American or even 2 hour drive from New York City standards. For radii between c. 60 and 150 miles the circle actually contains darker land when centered on NYC than Philly.

Ah, do you want to check that? I think you might have your chart upside down. The Andromeda Galaxy – with a declination of +41° is very much visible in the northern hemisphere, and most easily viewed from there. For southern observers, Andromeda never gets very far from the northern horizon. The Magellanic Clouds are presumably the dwarf galaxies you're thinking of, and they're both around -70° declination, deep in the southern sky. TenOfAllTrades(talk) 03:16, 5 November 2017 (UTC)[reply]

You're right, I was thinking Magellanic Clouds. Stupid me. In any case, you still need visual aids to make out anything other than a fuzzy star. Where I live, you are lucky to see Orion, Sirius and the Pleiades in the right season, and perhaps the Big Dipper. μηδείς (talk) 03:39, 5 November 2017 (UTC)[reply]

The Large Magellanic Cloud isn't small to the naked eye. And the Milky Way doesn't look too dissimilar to astrophotographs of spiral galaxies edge-on and is a bit more than a fuzzy star (360 degrees wide). Sagittarian Milky Way (talk) 04:08, 5 November 2017 (UTC)[reply]

You are contradicting a claim I didn't make. The fact that it's called a cloud kind of gives it away, doesn't it? μηδείς (talk) 23:10, 5 November 2017 (UTC)[reply]

Ah yes you're right, the visual aids is still about the Northern Hemisphere (I'll ignore the tropical northern since the view is so degraded that far from 70°S it's close enough). Nebula means cloud (coined decades after the telescope) so it's not blatantly obvious to me that a cloud has to be big. Sagittarian Milky Way (talk) 02:12, 7 November 2017 (UTC)[reply]

So now you are reverting to reverse time travel, linguistic nonsense, and what is not obvious to you, to score points? The objects were called Las Nubes de Magallanes when reported by Magellan's expedition. (Nube literally means cloud in English, and is not technical term referring to the small fuzzy objects which vexed Charles Messier who catalogued them to distinguish them from the comets which he was interested in or William Herschel who determined that the Messier Objects were comprised of stars.)

This predates the astronomical use of the term nebula with the astronomical meaning "cloud-like patch in the night sky" first recorded c. 1730. The suffix -ulus/ula is a diminutive derived from Latin, so of course nebulae are small, and "nebula" is not the equivalent of "nube", but of Spanish nebulosa. μηδείς (talk) 03:51, 7 November 2017 (UTC)[reply]

Okay you're right, little cloud. Looks bigger in a 'scope but I'm centuries too late to suggest nube. Sagittarian Milky Way (talk) 09:09, 7 November 2017 (UTC)[reply]

I did some searching on this question a while ago while writing a trivia-league question. Pretty much every source I checked made different assumptions and gave different numbers, but the consensus was clearly that under ideal naked-eye conditions on the Earth the number of stars you can see as individual objects at one time is a few thousand. The question is whether you can see stars of magnitude 6 or brighter, or 6.5 or brighter, or whatever; also, stars near the horizon are dimmed and you won't be able to see all of them that you could if they were higher. Anyway, I downloaded the Bright Star Catalog, which was available somewhere under here, and found 5,080 stars listed of magnitude 6 or brighter; 8,404 of magnitude 6.5 or brighter. Of course at any particular time and place about half of them will be below the horizon. So it's pretty safe to assume 2,000-plus; 3,000-plus, maybe not. --69.159.60.147 (talk) 04:36, 5 November 2017 (UTC)[reply]

The sky with the most individually distinguishable naked eye stars probably has the Milky Way near the zenith. The winter sky has more bright stars cause of the Orion Arm which we're in (but closer to the inner edge), the summer sky has more dim stars cause the Orion Arm's a minor spur of the Persus or something arm and the next arm in (Scorpius-Sagittarius?) is major but further (as one would expect from us being in a minor inner spur of the next outer major arm). The Southern Hemisphere's uhm, Northern Hemisphere spring (their autumn) sky probably has more individually resolved stars than the Northern Hemisphere's fall and you could still see some of the midnorthern latitudes' summer and winter stars when Centaurus or Crux is overhead so it's probably not when the Cepheus or Cassiopeia Milky Way is high. Sagittarian Milky Way (talk) 05:32, 5 November 2017 (UTC)[reply]

See Dark-sky preserve. There is an organisation which inspects areas and grades them [11]. 86.155.148.59 (talk) 15:22, 5 November 2017 (UTC)[reply]

As an aside, here's a link to a worldwide light pollution survey, presented as an overlay on Google Maps: link. (Sadly, I live in one of those big-city white areas at the ugly end of the Bortle scale.) The map is based on 2006 data, but most areas won't have changed much beyond a gradual worsening. TenOfAllTrades(talk) 15:26, 5 November 2017 (UTC)[reply]

I do wonder if we're taking the question in a bit of the wrong way. Counting stars and spotting Triangulum are certainly ways to assess viewing conditions, but I get the impression that the OP is perhaps at least as interested in a more qualitative description, with particular emphasis on similarities and differences between what you see with the naked aye versus photographs. Correct me if I'm mistaken, but I presume that the OP is new to dark-sky observing (and probably has fairly limited observing experience in general—welcome to the hobby!); learning to find the most obscure and difficult-to-see objects probably isn't the priority here. So what are the differences that will stand out?

A lot more stars. With the naked dark-adapted eye, good seeing (that is, good atmospheric conditions), clear skies, unobstructed view to the horizons, and (this is important) no Moon, you're looking at somewhere over 4000 stars at magnitude 6.5 or brighter: [12]. This compares quite favorably with the few dozen you might see from a city location, or the few hundred you might get at a suburban site.
But not all the stars. Telescopes, binoculars, even regular camera lenses all capture light through a front aperture bigger than the pupil of your eye, and so they collect a lot more light to play with. (This page shows the difference between a 200 mm medium-sized amateur telescope and the human eye in the first figure.) Film or digital camera sensors can collect that light over an extended period of time, too (several seconds, minutes, or even hours), to pull even the faintest objects out of the background. I know from experience that if I put my very average consumer-grade DSLR on a tripod outside with a good-but-not-stellar (ahem) medium-angle lens, I can shoot a five-second exposure that easily displays stars that are fainter than 9th magnitude—even from a badly-light-polluted city location.
Less color than you might expect. Color vision just isn't very sensitive. Most stars, even under ideal conditions, look plain white; a few of the brightest ones have visible color: [13]. Similarly, the small number of naked-eye nebula (like the Orion Nebula) are smudges of gray, not sprays of violet: [14].
Lower magnification and resolution. Globular clusters are smudges rather than dense piles of pinpoint stars. Most of the objects in the sky won't show structure or detail to the naked eye, just smudges and single points. Remember that the list of Messier objects was compiled by a frustrated naked-eye comet-hunting astronomer who wanted a catalog of all the little fuzzy smudgy things in the night sky that looked like they might be comets—but weren't. (Amateur astronomers refer to faint nebulae and distant galaxies – somewhat tongue in cheek – as 'faint fuzzies'.) For a few extended objects, you may only be able to see the brightest parts with the naked eye. For example, the Andromeda Galaxy is nearly three degrees wide (the full Moon is only about half a degree across) but you'll only be able to see a wee smudge in the middle with the naked eye.

All that said, don't get the impression that it's not worth looking at the night sky with the naked eye. It's magical. The sky feels close enough to touch. The Milky Way is awesome. Be patient and let your eyes get fully dark adapted. Do not look at your smartphone. Lie down on your back and soak it in. TenOfAllTrades(talk) 15:26, 5 November 2017 (UTC)[reply]

Actually those smartphones seem like they ought to be useful. Invent a way to put their display in a really dim adjustable "starlight mode" that is maybe 10-100 times brighter than the stars at arm's length. Use their various position-orientation spy stuff to get them to calibrate their position based on a camera photo of the moon, or else by user sighting at stars. Then have them present a light-amplified view of whatever is directly behind them. (Not by using the camera, which I *assume* is not yet spy-grade enough to see the stars, but based on orientation; the user would still need to align his head right) Wnt (talk) 13:49, 6 November 2017 (UTC)[reply]

This is a well established genre of phone app. I use an Android app called Star Map [15] that does exactly that, although it doesn't need to be calibrated since the phone has GPS. The link above also shows a number of other apps that seem to operate similarly: Star Walk, Sky View, Star Chart, Star Tracker, Night Sky, SkEye, etc. CodeTalker (talk) 15:27, 6 November 2017 (UTC)[reply]

Using food or money on research participants

When “animals” are used in research experiments, they are rewarded food. When humans are compensated for their time, they are given money. Is this just a widespread assumption by the researcher, or are humans really attracted to money over food? If a researcher has a low budget, then will offering a piece of fruit work instead of giving money? Or do researchers still have to allot some of the budget to paying the participants? 50.4.236.254 (talk) 23:55, 4 November 2017 (UTC)[reply]

The articles Human subject research and Animal testing give some perspective on these kinds of research, both of which are normally guided by ethical restraints, see ref. 1 and ref.2 respectively. Financial or food incentives may form part of the research methodology, or merely be necessary outlays to obtain participants. Blooteuth (talk) 01:20, 5 November 2017 (UTC)[reply]

(ec) There are some questionable assumptions there about how humans are compensated for their participation in research. Over the last few decades, I have received:

A smidgen of course credit (in an undergraduate introductory psychology course) for participation as a subject in psych experiments;
A chocolate chip muffin in exchange for a vial of blood (while a grad student) for a neighboring bio lab that needed a 'normal' control;
Nothing whatsoever in exchange for consent to carry out research using biopsy specimens collected in the normal course of a surgical procedure I underwent;
A small-but-not-negligible cash payment (enough for dinner and a pint at the local pub) for participating in a series of telephone surveys tracking my recovery from the surgery mentioned in the previous bullet.

In my very tiny sample of experience, research participation has seldom resulted in a cash payment, and food has been used as a perfectly acceptable reward.

More generally, there are serious ethical concerns around cash payments to research subjects. Research ethics boards (REBs) and regulatory agencies (like the FDA) tend to frown on studies that propose using overly-large payments to influence subjects and induce consent or agreement to participate in studies against their better judgement. These guidelines from UC Berkeley touch on a number of principles, and highlight the potential for undue influence or coercion. These guidelines from the University of Toronto draw a distinction between reimbursement (repayment for out-of-pocket expenses like transportation and parking) and compensation (payment – monetary or otherwise – for the participant's time and effort).

On the question of whether and how various rewards work, here's a quote from a relevant paper.

"However, empirical evidence demonstrating that payment is necessary and/or effective for the recruitment of clinical research subjects is limited. People appear to be attracted to research and motivated to participate for a variety of reasons. Healthy volunteers, who are frequently paid and unlikely to benefit medically from research participation, are often attracted to research and motivated to participate by money. Yet they appear to have a variety of other motives besides those of a financial nature for participation in research, including curiosity, altruism, sensation seeking, and desire for attention provided by physicians (24–26). Patient-subjects — those who suffer the disease or condition under study in a particular research protocol — are often motivated to participate by the hope of personal therapeutic benefit. When patient-subjects enroll in clinical studies and they understand the likelihood of direct medical benefit to be remote or nonexistent, their motivations are likely to be similar to those of healthy volunteers. Although patient-subjects are often offered payment for their participation in clinical studies, little research has been done to evaluate the extent to which money influences recruitment or their willingness to participate (21). Given the diverse motivations of subjects in clinical research and a lack of relevant data, it is difficult to know how much paying subjects helps to accomplish recruitment goals."

The short version is that different people are motivated by different things, and study participants often receive trivial compensation. TenOfAllTrades(talk) 01:39, 5 November 2017 (UTC)[reply]

The question is confusing "reward" as part of a research protocol itself (training a behavior, etc.) with "compensation" for being a participant. You don't need to pay mice, you just pay a breeder and then drop them in your maze. Token rewards involved in protocols depend on what behavior is intended to be learned. DMacks (talk) 01:49, 5 November 2017 (UTC)[reply]

From what I gather by talking with my fellow clinical trial participants, while some do it out of charity, they still need to take unpaid leave to participate, still other participated to raise funds while on an OE. I was one of the former, and I would be rather irked if I weren't comensated for my lost earnings. I already sacrificed my time, and it's exhausting being poked and prodded at all hours of the day and night. Offering me fruit instead of money would be an insult, I'd rather take nothing in compensation. Plasmic Physics (talk) 05:21, 5 November 2017 (UTC)[reply]

It's purely a matter of convenience. Animals would be given money too if only they could be persuaded to work for it. Looie496 (talk) 13:58, 5 November 2017 (UTC)[reply]

Volunteers may only eat what they are given (if they smuggle in food they may be discharged and/or not paid).[16] This is because diet affects how the body metabolises the trial drug. 86.155.148.59 (talk) 15:39, 5 November 2017 (UTC)[reply]

Like domestic animals in general, animals used in research are completely dependent on their human carers for all their needs, so food or water can be withheld for a period before the experiment so they have an incentive to work for it. If you could starve your human subjects in the same way they would also be willing to work for their food but as human subjects take part voluntarily you can't normally confine them and withhold food from them and so you have to find a different way to encourage them to take part. Usually the main drivers are altruism, simple curiousity or the possibility of helping to find a cure for a disease from which they suffer, and any money paid is to offset any financial losses they may incur, such as wages lost and/or travel expenses. Richerman (talk) 00:36, 6 November 2017 (UTC)[reply]

Does a couple of months' worth of grocery vouchers count? Plasmic Physics (talk) 19:15, 6 November 2017 (UTC)[reply]

Going back to my original comment, we're looking at a number of different concepts. There's reimbursement for out-of-pocket expenses, compensation for the value of a participant's time and effort, and (what I will call) rewards which might be motivational 'prizes' for completing tasks or accomplishing goals in an experiment—likely a psychology experiment. The original poster conflates a "reward" (the food in a maze, for a mouse) with "compensation"-type payment (money a human subject receives for participating in a study). Those are different things, with different consequences. Generally speaking, lab animals don't receive "compensation"; they get dropped in the maze whether they want to or not. TenOfAllTrades(talk) 19:37, 6 November 2017 (UTC)[reply]

November 5

Burqan 2 ballistic missile spesifications?

All over the news today is the claim that Saudi Arabia shoot down a Burqan 2 ballistic launced from Yemen. I have looked, but fail to find much of anything about the Burqan missile; who made/makes it, spesfication, design lineage, anything. Do anyone have any pointers or know of any resources on this missile? WegianWarrior (talk) 11:12, 5 November 2017 (UTC)[reply]

See Volcano H2 for our article. Perhaps some redirects need to be created. Tevildo (talk) 12:04, 5 November 2017 (UTC)[reply]

Thank you :) WegianWarrior (talk) 16:45, 5 November 2017 (UTC)[reply]

I have now created 3 redirects with variations as used by news broadcasters. Graeme Bartlett (talk) 21:05, 5 November 2017 (UTC)[reply]

Deodorant Manufacturing Process

How does a Deoderant remove foul odors? Is it activated Carbon which is used to absorb foul odors? — Preceding unsigned comment added by 117.194.220.156 (talk) 13:40, 5 November 2017 (UTC)[reply]

I think our deodorant article explains it in a reasonably clear way. Looie496 (talk) 13:56, 5 November 2017 (UTC)[reply]

Are you referring to body deodorants? Here is an article talking about how body deodorants work. Also see body odor. Bus stop (talk) 13:57, 5 November 2017 (UTC)[reply]

Personal anti-perspirants work by applying an astringent to the skin pores, thus reducing perspiration. Most body odour develops from bacterial action on stale perspiration. These are usually aluminium based, often based on alum (a common one in some countries is just rubbing an alum block over the skin). In the West, "aluminium free" anti-perspirants are sold by fashionable fools and charlatans when these are made from alum (which of course, contains aluminium).

Deodorants for personal use are mostly perfumes which camouflage odours, although often include anti-perspirants and some include biocides to try and reduce the skin bacteria. Some, like Lynx (UK) / Axe (US) are so powerful and generally unpleasant that they have become known as the smell of male teenagers. The phrase "Glasgow shower" (other despised neighbouring towns are available) refers to the practice of never washing, but merely spraying on another layer of artificial smell. Trying to remove skin bacteria is often not a good strategy: skin will have a colony of some bacteria, and removing the benign ones may encourage a worse group to predominate. Also the usual problem of antibacterial resistance can develop.

For cleaning fabrics, adsorbants are used, and have been used since ancient times. They aren't used on the body as they'd leave dust behind. Activated carbon isn't used on fabrics, because it would leave ingrained black dust behind, but fuller's earth is. A modern and more powerful version of this are the odour eliminators such as Febreze which are based on cyclodextrin molecules.Andy Dingley (talk) 14:32, 5 November 2017 (UTC)[reply]

Most Deoderant's simply use Salt to "paint" a zone with it which makes it inhospitable for the bacteria which naturally thrive on your sweat and dead skin cells and thereby produce the smell as waste product. So deodorants dont remove smell, they try to prevent it. Also deodorants often additionally contain perfume to make customers happy and secure of themselves. So you can make your own deodorant for a few pennies instead of buying the very expensive salt-based "beauty products"! Go try! --Kharon (talk) 14:48, 5 November 2017 (UTC)[reply]

What do you mean by "salt" here? Common table salt, sodium chloride? In which case, no they don't. Andy Dingley (talk) 15:00, 5 November 2017 (UTC)[reply]

He means Aluminium chlorohydrate. In chemistry, a Salt is any ionic electrolyte. --Jayron 32 14:54, 7 November 2017 (UTC)[reply]

Note that the correct spelling is deodorant. It's misspelled by two editors above. Akld guy (talk) 15:50, 5 November 2017 (UTC)[reply]

what is the nuclear reaction that occurs in radiation therapy?

? — Preceding unsigned comment added by 107.77.226.41 (talk) 20:39, 5 November 2017 (UTC)[reply]

Radiation therapy#Mechanism of action is the place to start reading, assuming you you mean what does the radiation do, not how is the radiation produced. DMacks (talk) 20:47, 5 November 2017 (UTC)[reply]

The short takeaway is that, at least for the primary mode of action, no nuclear reaction is involved at all. The particles create ionization (see ionizing radiation), which then acts chemically, not at the nuclear level. --Trovatore (talk) 20:50, 5 November 2017 (UTC)[reply]

Sorry to mince words - but a radioactive source is undergoing a nuclear reaction, all the time. It just happens to be a slow, low-energy reaction, when we compare it to a textbook Uranium-235-esque fission chain reaction. I am not qualified to say "why" a nuclear reaction can aid in medical treatment, but as Trovotore has correctly pointed out, there are many messy details pertaining to the secondary actions of the ionized particles, and subsequent chemical and biological effects. In my opinion, "almost nobody" knows if - or how - this works - but it is nonetheless an accepted medical practice in some parts of the world.

Most radiation therapy involves exposing a patient to a material - like fluorine or iodine - that undergoes a beta-decay reaction, in the hope that the emitted particles will have a helpful effect on the patient's ailment.

There is also an entire field of nuclear medicine that is much larger in scope than just radiation-therapy. Medical practitioners and researchers employ all sorts of nuclear physics to perform diagnostics and to treat patients. For example, positron emission tomography uses beta-decay (positron emission), a nuclear reaction, to "light up" the insides of a patient during medical imaging. In fact, it is more common to use nuclear medicine for diagnosis, rather than for treatment.

Using nuclear medicine for therapy - inverventional nuclear medicine - typically involves intentional exposure of the patient to a radiological source. Several methods are listed in our article. Almost always, the radiological source is iodine, fluorine, or barium, which all naturally undergo the nuclear reaction called "beta decay." Our article lists several other materials. The actual materials that get used depend on the patient's condition, the doctor's choices, and availability and regulation in various parts of the world.

I am aware of at least a few places in the world that use "other" nuclear reactions: for example, neutron exposure, and even muon beam radiotherapy. Both of these methods are extremely uncommon: in fact, all interventional radiotherapy is "pretty uncommon," but the more esoteric the particle (like the mild-mannered neutron or muon!), the less likely that a well-credentialed practicing clinical cancer doctor will have the means or the motive to choose to employ it. It is comparatively easier for a clinician to obtain and prescribe radiological medicine like iodine: if the clinician wants to use a neutron source for therapy, they need a special machine in a special facility. Very few of these machines exist, in low single-digits, worldwide - so the patient would have to be referred to an extraordinarily special oncology/nuclear-medicine research clinic.

(Side note): I'm participating in an online refresher-class, titled "Dr. Bill Perry and Valerie Plame induce further informed but unhealthy paranoia about nuclear technology," or something like that - so, part of me wants to shout out into the hypothetical void: "what the heck is a so-called oncologist doing with a slow neutron source in South America anyway, selling it?" ... but I'm drifting off topic.

In layman's terms -

Most of what we call "nuclear medicine" is diagnostic ("putting the patient in a special type of X-ray machine for a few minutes"); and if the doctor decides to go farther, the majority of interventions ("giving the patient a dose of something") involve exposure to light isotopes undergoing natural decay - like iodine beta-decay - frequently in the form of a pill, a suppository, or an injection.

Nimur (talk) 15:27, 6 November 2017 (UTC)[reply]

You seem to have largely omitted radiosurgery which is a form of interventional radiation therapy (usually using gamma rays) that is now widely available. Dragons flight (talk) 18:57, 6 November 2017 (UTC)[reply]

Indeed, that is yet another form of nuclear medicine and it appears to be in widespread use. Nimur (talk) 19:48, 6 November 2017 (UTC)[reply]

Which fungi species are in US food?

In the European Union, the species of mushroom in a food product have to be declared, I think.

According to producer information, the product "Lipton, Recipe Secrets, Recipe Soup & Dip Mix, Onion Mushroom" contains [17]:

"Mushrooms* A type of fungi consisting of a stalk with an umbrella-shaped cap.
Growing Method Conventional Farming
Country of Origin China / India
Ingredient descriptions have been provided by Lipton"

Is there a way to find out which exact species of fungi or mushrooms are used in this or other products sold to consumers in the USA? Rosenkohl (talk) 22:28, 5 November 2017 (UTC)[reply]

Cheap food mushrooms are Agaricus bisporus, but that doesn't actually help that much, because there are some quite distinct cultivars within that. Most of the "mushrooms" you see in a British or US supermarket are this species, including globular white button mushrooms, large flat "field" mushrooms, brown chestnuts, large portabellos and small portabellini. If you find collected flat white mushrooms in a market, rather than farm cultivated, they may be Agaricus campestris (the real "field" mushroom) instead, but these aren't grown intensively. In mainland Europe, of course the range is vast and most that are edible, are collected and eaten.

As a wild guess from knowing mushroom growing, mushrooms for flavouring like this are usually the small white button mushrooms (as the fastest growing) and may be the stalk trimming after the caps have gone for more visibly decorative uses, such as pizza toppings.

Also, just ask Liptons. Andy Dingley (talk) 23:33, 5 November 2017 (UTC)[reply]

Your premise about the mushroom species having to be declared in the EU seems to be mistaken: Tesco Cream Of Mushroom Soup 400G (UK) only says " Mushroom (6%)" and Carrefour Soup Crème de Champignons avec Morceaux 460 ml (France) says "champignons 10%". Alansplodge (talk)

November 6

why is the bond order of water 1.5 for each O-H interaction??

In the MO treatment of water, there are 3 bonding interactions and one non-bonding interaction for a total average bond order of 1.5, 8 electrons in 4 filled orbitals and 2 empty orbitals. While tutoring organic chemistry this evening I could not adequately explain this discrepancy between MO theory and VB theory except to observe that water has a bond-length of 960 pm whereas methane is 1096 pm. I am familiar with MO treatment of pi systems. Usually 1.5 bond orders can be thought of arising from alternate resonance structures or donating into orbitals that are antibonding for one bond pair but bonding for a different pair. Where is this resonance structure for water though? There is no resonance structure where there is a double bond between O and H?? Yanping Nora Soong (talk) 00:57, 6 November 2017 (UTC)[reply]

Well, to get the ball rolling I found the top hit for water molecular orbital at [18], which says "The five occupied and the lowest three unoccupied molecular orbitals of the isolated molecule (1a1)2(2a1)2(1b2)2(3a1)2(1b1)2 were calculated using the Restricted Hartree-Fock wave function (RHF) using the 6-31G** basis set." This is based on data from [19]. I should admit that I know so little about electron momentum spectrometry and Hartree-Fock theory that I haven't even gone hunting for this on Sci-Hub, at least not yet. I am rather surprised by the way that the molecular orbitals as drawn at the first source seem almost oblivious to the hydrogens except as landmarks of orientation; the antibonding orbitals seem to respect them yet are drawn with nodes near the hydrogen nuclei... Wnt (talk) 04:01, 6 November 2017 (UTC)[reply]

Could you (Yanping Nora Soong) state what your MOs actually are? Specifically, what are the filled three bonding ones, and especially the filled non-bonding one (what atomic contributors to each)? We have a Chemical bonding of H2O article that discusses various approaches. DMacks (talk) 05:26, 6 November 2017 (UTC)[reply]

Page 148 of Inorganic Chemistry by Miessler and Tarr has an MO diagram of water which shows the oxygen 2s orbital unhybridized and the three oxygen 2p orbitals split into three different energy levels, the lower two of which hybridize with the hydrogen 1s orbital and are bonding. Both the 2s orbital (lowest energy) and the highest energy 3p orbital are shown as non-bonding, and only associated with the oxygen atom (i.e. the lone pairs). So according to this diagram, it's two bonding orbitals and two non-bonding orbitals.--Wikimedes (talk) 05:47, 6 November 2017 (UTC)[reply]

I think Yanping is refering to the hybridised MO solution as depicted in Molecular orbital diagram#Water and Chemical bonding of H2O#Molecular orbital treatment of H2O. In the hybridised MO solution, there are three filled bonding MOs (2a₁, ~~1b₁~~1b₂, 3a₁), and one filled non-bonding MO (~~1b₂~~1b₁), resulting in the average O-H bond order of 1.5. In the simple MO solution (also depicted in the latter link), the third MO is considered to be non-bonding reducing the bond order to the conventional integer, 1. Treatment of a molecule according to VB theory correlates more with the simple MO solutions. In other words, while water technically has an average O-H bond order of 1.5, VB is black-and-white and simplifies this understanding to eliminate the bonding or anti-bonding interactions which may be considered weak or borderline. According to the MO solution for water, the oxygen atom only has one lone pair of electrons, the second pair is very weakly delocalised over the molecule, residing mostly on the oxygen. Plasmic Physics (talk) 10:07, 6 November 2017 (UTC)[reply]

You see, an MO diagram is very subjective, it is the direct result of how an individual scientist chooses to interpret the solution generated by the MO model they implemented. When you want to put things in nice little boxes of bonding, anti-bonding, and non-bonding, you have to select the contrast so to speak. The thing is that when you analyse the raw data from the model to construct your diagram, you have to decide how much interaction and of what kind equates to which kind of bond. One scientist can look at the data and say that although the interaction between two atoms is additive, it is too weak to be considered a bonding orbital, and labels it instead a non-bonding orbital, another scientist may have chosen a lower interaction limit, and instead insist that it is in fact a bonding orbital. It's all about how complicated you want to make it. You'll realise that when you have a lower interaction limit, you more often than not have to invoke hypervalency to explain bonding in simple molecules, and in the opposite extreme, your molecules end up being very electron-deficient. Plasmic Physics (talk) 11:34, 6 November 2017 (UTC)[reply]

Alright, this is very ignorant (question not answer), but when I try to make sense out of the [20] link above I see 2a1 looks like s bonds to each hydrogen and 1b2 looks like a p bond interacting with both hydrogens. I would think I could, in some sense, hybridize these to sp orbitals and have one of these bonds to each hydrogen. The figure lists 1b1 as a nonbonding, not a bonding orbital, and does not show any hydrogen contribution to it; i.e. it is a plain vanilla p orbital from the oxygen atom, left untouched. That leaves the weird thing, 3a1. There are the two s orbitals in black, and one lobe of a p orbital in black between them. I would assume as with an sp that the thing adds up to something with a smaller negative lobe and a large broad density in the positive lobe that encompasses the oxygen and hydrogens? In any case, there is just one of these for two hydrogens, so I would be prone to guess this is where the extra .5 bond order can be found... however it works. Given that it involves a perpendicular p orbital I assume it is formally some sort of pi bond. Wnt (talk) 14:21, 6 November 2017 (UTC)[reply]

Sorry, I've corrected my typos. Plasmic Physics (talk) 18:31, 6 November 2017 (UTC)[reply]

Frankly speaking, you'd be lucky if the bond orders predicted by VB theory agree precisely with that predicted by MO theory for anything except diatomic species. Plasmic Physics (talk) 23:29, 6 November 2017 (UTC)[reply]

Yes, but when a group of blind men grope an elephant, viewers hope to see a happy ending. Is there any chance that the 3a1 bond here is analogous to a three-center two-electron bond, sort of a reverse instance of something like this? That way you could show a higher bond order in valence theory. Admittedly, this still has the very large issue that the hydrogen has to be part of two different bonds by all appearances, with more than two electrons in its shell, but I would think there's no way around that and still claim a 1.5 bond order. Somehow the oxygen lone pair would need to be donated back to a hydrogen 2s after the 1s has formed its main sigma bond. Is any of that not nuts? Wnt (talk) 03:23, 7 November 2017 (UTC)[reply]

LOL. Yes, it could be considered the reverse. No, there is no way around it, except to sweep it under the rug by using the simplified MO diagram. Fortunately, each hydrogen only has to put up with a small contribution by one extra electron, like the third wheel on a date that spends most of the time at the bar, but still drops by to interupt the romance. Plasmic Physics (talk) 04:05, 7 November 2017 (UTC)[reply]

For what it's worth, as I was saying, just because the diagram in the link shows the 1b₁ MO to be non-bonding does not make it neccesarily so. That is just the interpretation of the scientist who drew it. The oxygen px orbital could in theory interact additively with the anti-sigma bond in the dihydrogen. Plasmic Physics (talk) 10:35, 7 November 2017 (UTC)[reply]

Well, if this way of looking at it is valid, then it seems like the contribution of the 3a1 bond to the hydrogens can't be too minor, because the two "sp orbitals" in the MO diagram produced from a single p will be voting for a 180 degree bond angle, and the apparent p orbital will be abstaining. According to this the affinity of hydrogen for electrons in its second shell should be the only thing pulling it down into range of the oxygen's perpendicular p orbital, which I would think votes for a 0 degree bond angle. Wnt (talk) 12:28, 7 November 2017 (UTC)[reply]

Actually, if we take east to be zero, the 3a₁ is voting for a 0 degree allignment, and the 1b₂ is voting for a 90 degree allignment. They partially cancel each other to get the proper allignment. That's how molecules get their shape, different MOs fighting with each other, until the equilibrium is reache that gives the most stable allignment.

It no so much hydrogen's affinity for the extra electron, as it is the affinity of the p-orbital for hydrogen. Compare how the bond angle changes as you go down group 16. Plasmic Physics (talk) 19:27, 7 November 2017 (UTC)[reply]

Drone (bee)

The article states: "They convert and extend the queen's single unfertilized egg into about 10 million genetically identical male sperm cells." But what exactly does that mean? Does the queen only lay one single egg? And what about these millions of sperm cells – in one egg? What concrete significance do they have for that single egg? Sorry, but I'm a complete layman. Thanks in advance for any assistance. Best wishes--Herfrid (talk) 20:18, 6 November 2017 (UTC)[reply]

The "single unfertilized egg" is the one from which the drone hatched.

The idea is that from that one unfertilized egg, you get (from the drone) millions of sperm cells with the same dna as the drone's mother. ApLundell (talk) 21:15, 6 November 2017 (UTC)[reply]

See haplodiploidy, Parthenogenesis#Insects and Hymenoptera#Sex_determination. Male bees are weird. They have no father, but they do have grandfathers. And they cannot have sons. They also have roughly half the genome of their sisters. This is also why sisters are more related to each other than they are to their mother or father, and is thought to be part of the reason why eusociality evolved in the Hymenoptera.

That's a confusing and poorly sentence you quote, by the way, I will fix it later when I get a chance. SemanticMantis (talk) 22:19, 6 November 2017 (UTC)[reply]

November 8

Earth-temperature brown dwarf

How massive would a brown dwarf have to be to have Earth surface temperature? Also what would his radius be then? Would this object be dense enough for a spacecraft to land or float on it (maybe with the aid of a balloon)? I'm thinking of something like WISE 0855-0714 but warmer. 93.136.44.140 (talk) 02:04, 8 November 2017 (UTC)[reply]

Temperature is a bit independent of size, and the older it is, the cooler it will be. Also at what point do you measure the temperature? If it is all gas the temperature may appear to radiate in the infrared at 300 K, but deep down it would be hotter. See Y-type star and Sub-brown dwarf for what we have. Graeme Bartlett (talk) 03:56, 8 November 2017 (UTC)[reply]

Well the core creates some heat (esp. if you need to fuse deuterium to get >300 K) so the temperature should over time level off asymptotically towards some limit, so let's say the object is free-floating, pretty old and at/near that temperature, and it's ~300 K. I suppose I'd want that temperature to be at the cloud layer at 1 bar pressure, but I'll settle for blackbody temperature if we don't know enough about sub-brown dwarfs to estimate in that detail. Can we infer mass & radius from this or will they depend heavily on metallicity and such? I'm wondering about this because I was intrigued by the fact that all brown dwarfs down to planets of Jupiter's mass have roughly the same radius due to matter degeneration. 93.136.44.140 (talk) 04:38, 8 November 2017 (UTC)[reply]

Easy: gas giants don't have surfaces!. μηδείς (talk) 16:48, 8 November 2017 (UTC)[reply]

Let's call the surface the place where atmospheric pressure is 1 bar, as in Jupiter#Atmosphere. 93.139.45.186 (talk) 17:35, 8 November 2017 (UTC) (original poster)[reply]

As the first reply says they get cooler with time as they don't do any fusion, or at least only the larger ones do and that stops after a while. The heat they generate is from gravity as they formed and it dissipates with time. There's not a great deal of difference between them and a gas giant like Jupiter except mass - they don't do anything too much different. They are not stars. To float you need something that is less dense than what it is floating in, the atmosphere can contain lots more chemicals than the sun but is still mostly hydrogen and helium so unless you can have a strong ball containing a lower pressure than outside like a submarine but much much lighter that would be pretty much impossible except with a large hydrogen balloon. Dmcq (talk) 17:59, 8 November 2017 (UTC)[reply]

Ok, I see I had some wrong assumptions. How about this: suppose there's a planet 5 billion years old and of Jupiter's composition, which evolved like Jupiter up to, say, 1 billion years after its "birth", when it was ejected by deus ex machina from its star system and ended up floating in interstellar space. Aliens descend into its atmosphere and measure that at the altitude where pressure is 1 bar, the temperature is 300 K. Is this enough data to estimate the planet's mass and radius, or do brown dwarfs vary too much in characteristics, or do we simply not know enough about this yet? 93.139.45.186 (talk) 19:51, 8 November 2017 (UTC)[reply]

Aliens in orbit around this body could estimate the mass directly from the gravitational force on their ship, and the radius by direct observation of occultations. The temperature and pressure would be irrelevant to such observations. μηδείς (talk) 22:43, 8 November 2017 (UTC)[reply]

Yeah sure, but can we? Is there a model that describes the relationship between temperature, radius, etc.? I'm interested in how to calculate that stuff. 93.139.45.186 (talk) 23:00, 8 November 2017 (UTC)[reply]

The speed of a body in orbit about a primary is independent of the orbiting body's mass, except that when we can calculate a barycenter of a system we can calculate the relative masses. If your brown dwarf has satellites of known distance and orbital velocity, then its mass could be determined. But if all we have are distant images, then we are making guesses based on libido and presumed composition. But a comparison of Saturn, large, cold and less dense than water with Jupiter, not too much larger, but hotter and denser, shows that there are many presumptions made when we don't have the full body of information needed, and are going on guesses due to brightness of the size and albedo. You can check the history of observations of Ceres and Pluto to see how difficult accurate measurements are without the needed observations. Of course your aliens would have those observation once they were in orbit, as they would know their own mass and orbital velocity and the actual albedo and specifically the radius of your brown dwarf. μηδείς (talk) 02:32, 9 November 2017 (UTC)[reply]

Ah yes, that makes perfect sense. I completely forgot how different Saturn is from Jupiter. I was hoping that one could make some nice relation like M-sigma or Stefan-Boltzmann law, given that there is a real and not very high limit on planet radius at low temperatures, but yes there would be too much variety in initial conditions to estimate anything. Thanks for the help folks. 93.139.45.186 (talk) 05:26, 9 November 2017 (UTC)[reply]

Name of fallacy: mixing up unrelated variables?

How would you call it when you lump together not quite analogous variables (for example, unemployed astrologers and unemployed astronomers) and calculate the average (or whatever)?--B8-tome (talk) 13:46, 8 November 2017 (UTC)[reply]

To mix apples and oranges? By the way you might like James–Stein estimator#Interpretation where they mix up the speed of light, tea consumption in Taiwan, and hog weight in Montana all together ;-) Dmcq (talk) 14:39, 8 November 2017 (UTC)[reply]

The corresponding article, Apples and oranges, has some further information under the 'See also' section. --Hofhof (talk) 20:36, 8 November 2017 (UTC)[reply]

Except there's no prohibition against combining apples and oranges or categorizing them together, only comparing them as if they were interchangeable. Comparing unemployed astrologers to unemployed astronomers could be a useful metric to figure out how gullible a society is. However, adding them together because you think they're similar fields - as in the OP's scenario - would be an error. I have a feeling there is a term from statistics that describes this situation, but I can't seem to put my finger on it. Broadly, it's an error in classification. Matt Deres (talk) 13:46, 9 November 2017 (UTC)[reply]

It isn't a fallacy, but in statistics this sort of situation is known as heteroscedasticity. Looie496 (talk) 01:12, 9 November 2017 (UTC)[reply]

Yes, and along the lines that Matt points out, it's not even always problematic. Certainly this is not a formal fallacy. Formal logical fallacies are about using logic faultily, not about making bad decisions. If anything, this may (sometimes) be classed as a informal fallacy, because the problem is with the assumptions, not the logic of any statement or argument. SemanticMantis (talk) 16:53, 9 November 2017 (UTC)[reply]

Industrial production of methane

What makes production of methane in an industrial scale so difficult? Can't you just use any biomass mixed with the proper bacteria to obtain it? Wouldn't the CO2 balance of burning this methane be neutral? --Hofhof (talk) 20:38, 8 November 2017 (UTC)[reply]

But methane is produced on an industrial scale in landfills by bacteria from any biomass. So, it is not very difficult. See landfill gas. Ruslik_Zero 20:45, 8 November 2017 (UTC)[reply]

That's not industrial production, that's just production. It only counts as an industry if you catch it and use it. Our article on that is at Landfill_gas_utilization. A perhaps more relevant article on general biomass production of methane is at Biogas. SemanticMantis (talk) 22:07, 8 November 2017 (UTC)[reply]

The question of carbon neutrality depends on the time scale in question. If for example, all the biomass was produced by plants and animals that were grown in a given year, then yes, the burning of methane produced by them would only release CO2 in to the atmosphere that had already been in the atmosphere in the beginning of the year. However, you also have to account for all the energy inputs to the hypothetical biogas plant (does is use any electricity, do people drive there to work, etc). Not to mention the carbon footprint of the biomass in question (E.g. corn has a massive carbon footprint, due to all electricity (and thus usually fossil fuels) needed to make the fertilizer for it (Haber process). All these considerations are part of why Life-cycle_assessment of energy and food production is very difficult to do properly. SemanticMantis (talk) 22:07, 8 November 2017 (UTC)[reply]

One issue with methane production is in producing only methane. Contaminants with sulphur in them are both smelly and also corrosive when burned. Andy Dingley (talk) 22:11, 8 November 2017 (UTC)[reply]

November 9

Forensic analysis

Are there forensic techniques which can determine, by analyzing microscopic scratches, markings, etc., whether a large rock had made an impact against a painted metal surface, in the absence of damage visible to the naked eye (provided, of course, that the surface had not been repainted afterward)? In other words, suppose someone threw a large rock against a car, but it bounced off without causing any visible damage -- is it possible to prove that this happened? 2601:646:8E01:7E0B:0:0:0:EA04 (talk) 09:25, 9 November 2017 (UTC)[reply]

I doubt much can be told if nothing is straightforwardly visible. The paint on modern cars is a flexible cross linked polymer, not an enamel, so there won't be small cracks. It is amazing what forensics can do but I can't see how even if they found something they could tell when it happened and cars are always being hit by small stones and this as they are going along. Dmcq (talk) 10:35, 9 November 2017 (UTC)[reply]

Without answering the specific question, which is probably outside of the realm of this desk, I can direct the reader to concepts like trace evidence analysis which is a HUGE sub-discipline within forensic science. Our article is short, but the answer to your question is part of trace evidence analysis, and if you want to know what that field can do, that is a phrase to punch into google to research more. --Jayron 32 12:18, 9 November 2017 (UTC)[reply]

iPTF14hls, cause of survival of explosions?

Could iPTF14hls contain a huge amount of weakly interacting dark matter? Because the dark matter is weakly interacting, it wouldn't get expelled by explosions, and its strong gravity could suck more fusionable matter in to fuel a later explosion. Thanks144.35.114.29 (talk) 19:47, 9 November 2017 (UTC)[reply]

Stellar objects do contain dark matter as there is no plausible mechanism that can explain how dark matter is captured into a stellar object in the first place - it is weakly interacting after all. As to iPTF14hls it is likely not a supernova at all. It just looks similar. Ruslik_Zero 20:13, 9 November 2017 (UTC)[reply]

??144.35.45.45 (talk) 00:25, 10 November 2017 (UTC)[reply]

Site engineers

If site engineers are entry level roles, why are there trainee and assistant site engineer jobs and why do nearly all site engineer jobs require previous experience of it? 94.10.251.123 (talk) 23:56, 9 November 2017 (UTC)[reply]

Infrastructure vs building engineering

Why is it that engineers and construction specialists working on buildings tend to stick to buildings, and those working on infrastructure tend to stick to infrastructure? I see very few who cross between the 2. 00:23, 10 November 2017 (UTC) — Preceding unsigned comment added by 94.10.251.123 (talk)