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January 1

Process capability index

How come the Process capability index is abbreviated as ${\displaystyle C_{pk}}$ instead of ${\displaystyle C_{pc}}$? Where did the "k" come from? 731Butai (talk) 05:19, 1 January 2016 (UTC)

This article says that the k stands for "centralizing facteur" . ←Baseball Bugs carrots→ 05:40, 1 January 2016 (UTC)

One guy claims it stands for a Japanese word. ←Baseball Bugs carrots→ 05:44, 1 January 2016 (UTC)

On here, someone makes the same claim, but someone else says that that's wrong and it actually comes from the "k-statistic", which she says is an old name for the z-statistic (otherwise called the standard score or z-score). She says this in an authoritative manner, but I would not know. For what it's worth, k-statistic apparently has a different meaning today. --76.69.45.64 (talk) 07:41, 1 January 2016 (UTC)

Other compounds of Krypton not included

A quick web-search turns up: Krypton Tetrachloride KrCl4; Krypton Difluoride KrF2; Krypton Hexabromide KrBr6; Krypton Dichromate Kr2Cr2O7; Krypton Chromate KrCrO4; Krypton Tetrafluoride KrF4; and Krypton Dioxide KrO2. Is there any reason none of these are included? There may be, but it's not obvious what it is. Eldin raigmore (talk) 06:44, 1 January 2016 (UTC)

Because you didn't add them to the article?--Jayron32 06:51, 1 January 2016 (UTC)

Any content to be added would need a WP:RS citation. Careful..."a quick web search" can turn up lots of material that does not meet the verifiability requirement for encyclopedia content. For example, all I see in google for "krypton dichromate" is its use as a distracter in a multiple-choice problem-set that is solely about chemical nomenclature. DMacks (talk) 22:41, 1 January 2016 (UTC)

References

1. http://www.endmemo.com/chem/common/krypton.php

Wedge-Tailed Eagle eyesight

Recently I read that wedge-tailed eagles can see in both the infra-red and ultra-violet spectrums as well as in the normal range of human sight. What I'm wondering is how do people know this? The only idea that I could think of is that dissection of the eye has led to people thinking this. If so, what differs from the eagle's eye to our own? 1.136.96.24 (talk) 09:15, 1 January 2016 (UTC)

so where did you read this, and why didn't you ask the author? Greglocock (talk) 10:10, 1 January 2016 (UTC)

Sorry here is the link to the page: Wedge-tailed eagle#Behaviour and diet, and that paragraph has not been sourced. 1.136.96.24 (talk) 10:28, 1 January 2016 (UTC)

If it hasn't been sourced it quite possibly is incorrect. It says here "birds do not see above about 700 nanometers. While some birds range into UV, IR light is as invisible to them as it is to us" and, although it's a blog, it's well sourced. From that, one way to tell is to see if the birds react to IR or UV illumination. Richerman (talk) 16:13, 1 January 2016 (UTC)

You should also read the following:

• http://skeptics.stackexchange.com/questions/30796/is-this-comparison-of-wedge-tailed-eagles-and-bald-eagles-accurate

• http://physics.stackexchange.com/questions/147746/why-human-and-most-of-vertebrates-cannot-see-near-infrared-light-720nm-1500nm

I've deleted the assertion about IR from the article. Richerman (talk) 16:31, 1 January 2016 (UTC)

Okay, thanks. 1.136.96.238 (talk) 19:58, 1 January 2016 (UTC)

Chess computer calculations

When it's stated that chess engines evaluate millions moves per second, do they include Tal-styled sacrifices of heavy pieces that superficially look losing? Or the calculations stop whenever they see a heavy piece sacrifice due to famous materialistic computer approach? I know that computers can sac light figures, but what about heavy pieces in exchange for unstoppable attack? Brandmeister 09:37, 1 January 2016 (UTC)

Our article Computer_chess states:

Chess programs differ in terms of how and what types of pruning and extension rules are included as well as in the evaluation function. Some programs are believed to be more selective than others (for example Deep Blue was known to be less selective than most commercial programs because they could afford to do more complete full width searches), but all have a base full width search as a foundation and all have some selective components (Q-search, pruning/extensions).

It goes on to say that "In addition to points for pieces, most evaluation functions take many factors into account, such as pawn structure, the fact that a pair of bishops are usually worth more, centralized pieces are worth more, and so on." So it sounds like some engines might exclude heavy sacrifices outright, while others might just highly penalize them in the evaluation function. OldTimeNESter (talk) 10:29, 1 January 2016 (UTC)

The cost of searching is an exponential function of depth, with quite a large multiplier. Shallow searches are so cheap that it is worth performing them even for moves that look very bad. In other words, no serious program is going to miss a sacrifice on the next move that pays off three moves later, regardless of how large the sacrifice. The possible difference comes in a situation where the computer is exploring, say, the possibility of a large sacrifice five moves in the future, which doesn't pay off until five moves after the sacrifice. Looie496 (talk) 18:07, 1 January 2016 (UTC)

With a fixed availability of compute power, you have a choice:

1. to do a 'shallow' search - just a handful of moves ahead - then use a lot of horsepower to evaluate the resulting board positions by looking at a bunch of heuristics (less lost pieces is good, strong pawn structure is good...etc). You hope that the resulting scores are accurate estimations of the 'goodness' of the board position.
2. to do a 'deep' search - looking as far into the future as possible - then doing a very rapid scan of the gazillions of resulting positions. Because you're examining many more possible future board positions, you don't have as much time to do a really detailed analysis of each position - but hopefully, by looking further into the future, you don't have to.

Deep blue mostly does the latter. Calling it a "computer" is slightly misleading because most of the computational power came from custom circuitry that did nothing but search and score positions - they were not programmable in the normal sense of a computer - just dedicated circuitry. This super-fast hardware allowed it to look deeper into the future than other chess systems - but that inherently limited the complexity of the board position scoring system.

Both approaches will tend to "prune" the rapidly exploding "tree" of possible board positions by rejecting the obviously bad ones and looking deeper into the more promising-looking ones.

These approaches mean that sometimes a deliberate sacrifice of a high-value piece will be noticed as a "good move" for the computer because the search is deep enough to "see" the ultimate payoff...but other times, if the payoff is too far into the future, the benefit will be missed. Shallow search plus complex scoring systems result in chess programs that aren't good at seeing long-term benefits of sacrifices - deep searchers do much better at that. But deep search software can't easily make use of the many 'rules of thumb' that human chess players know about board position strength - such as measuring how blocked or unblocked various pieces are - so they may fail completely to 'understand' the value of things like pawn centrality, having to 'deduce' the value only by searching future board positions that result from having good versus bad pawn positioning has on other simpler metrics such as the value of captured pieces.

Both approaches can produce great chess computers - but the deep search approach is superior when custom hardware is involved because you can use a large quantity of identical chips that are individually very fast - but very stupid devices.

SteveBaker (talk) 04:44, 3 January 2016 (UTC)

U.K. ceng

Does the UK Engineering Councils Chartered Engineer (UK) status count as a level 7 qualification in the National Qualifications Framework if you get it without a masters degree? 90.201.187.44 (talk) 17:12, 1 January 2016 (UTC)

No. A CEng on its own is not an educational qualification, and therefore doesn't count on the Qualifications and Credit Framework scale. This is the official register from Ofqual - the Engineering Council is not listed as an accredited organization (although McDonalds and the Worshipful Company of Spectacle Makers are). Tevildo (talk) 19:53, 1 January 2016 (UTC)

It seems you need to reach level 7 qualification to obtain UK Chartered Engineer status. I don't see how you can obtain it without being at this level, independent of the route to it. --Llaanngg (talk) 21:49, 1 January 2016 (UTC)

Yes, the CEng requires an MEng degree, but it isn't itself an academic qualification. Someone interested in your qualifications will want to know the details of the underlying MEng, not the resulting CEng. Tevildo (talk) 23:12, 1 January 2016 (UTC)

You can get CEng if you can demonstrate you've met the learning objectives equivalent to an MEng. 2A02:C7D:B91D:CC00:4DD8:2342:2A48:E95F (talk) 00:30, 2 January 2016 (UTC)

Indeed, and you can get grandfathered in if you met the academic qualifications at the time you graduated. Somewhere in a box I have a letter confirming that my BA was sufficient. Greglocock (talk) 02:22, 2 January 2016 (UTC)

Humid desert climate?

I've noticed that Dubai is pretty humid, but it's still classified as a desert, and based on vegetation coverage of the surrounding area the classification is warranted. So, two questions.

1. Why is Dubai not fertile? Why doesn't the humidity provide moisture for many plants?
2. Why is Dubai sandy? I thought that hot deserts were sandy from temperature extremes (day vs night) breaking the rocks from contraction and expansion. And the humidity of Dubai means that the day–night extremes are not very severe.--Leon (talk) 21:29, 1 January 2016 (UTC)

It's probably like the difference between drinking champagne and breathing the vapors. Sagittarian Milky Way (talk) 22:30, 1 January 2016 (UTC)

It's possible that the humidity rarely reaches the level where precipitation occurs. In that case, not much of it gets into the soil, apparently not enough to support crops. StuRat (talk) 04:39, 2 January 2016 (UTC)

Sulfuric acid spill

The recent sulfuric acid spill in Australia has taught me something new -- I didn't know the corrosive liquid is transported in such a vast quantity. I suppose it is for industrial uses. I'd like to know if it is common to transport it in such a massive quantity? --BorgQueen (talk) 21:35, 1 January 2016 (UTC)

I can't cite any sources, but I remember reading somewhere that it is among the most common industrial chemicals, and, yes, produced and transported on a massive scale. —Steve Summit (talk) 21:40, 1 January 2016 (UTC)

According to sulfuric acid, 180 million tonnes were produced in 2004. It is among the most commonly produced chemicals and has many uses. I'm sure it is pretty common to transport it in large quantities, though I don't have an immediate reference. Dragons flight (talk) 21:47, 1 January 2016 (UTC)

As one datapoint, estimated total 200,875 railcarloads of sulfuric acid in the US for 1998 through 2001.Surface Transportation Security, vol. 20, Transportation Research Board (NCHRP Report 525), 2006, p. A-8 DMacks (talk) 22:24, 1 January 2016 (UTC)

Sulphuric acid is far from the worst chemical transported at scale. There used to be whole trainloads of liquid chlorine passing near my home town. Caused some concern, as you may imagine. Fgf10 (talk) 23:49, 1 January 2016 (UTC)

Just hope they don't transport the liquid chlorine in the same train as something that might explode in an accident. --76.69.45.64 (talk) 01:16, 2 January 2016 (UTC)

See also Graniteville train disaster. No explosives necessary. Tevildo (talk) 01:46, 2 January 2016 (UTC)

That's also very bad, but it's a different problem from the one in Mississauga. --76.69.45.64 (talk) 11:09, 2 January 2016 (UTC)

Senior scientist

How comes that a common term such as senior scientist doesn't have an article (or a redirect)? --Leyo 22:52, 1 January 2016 (UTC)

It is listed in List of academic ranks. I am not sure a redirect is needed.--Llaanngg (talk) 23:28, 1 January 2016 (UTC)

Thanks. If the redirect in Adiunkt is fine, it would be fine here, too, I guess. --Leyo 23:43, 1 January 2016 (UTC)

I think common is a relative term here. I'm guessing it may be common in some countries (Canada and translated from Bulgarian, according to our table?), but I've never heard it here in the UK as an academic 'rank'. It seems a rather non specific term. We prefer more descriptive terms (for instance, I am a research associate) Fgf10 (talk) 23:47, 1 January 2016 (UTC)

"senior scientist" site:ac.uk gives ~7500 Google hits ("senior scientist" site:.ca ~44000). I would say, it's common enough. ;-) --Leyo 00:41, 2 January 2016 (UTC)

True, but "research associate" site:ac.uk gives 154,000 Google hits, "research fellow" site:ac.uk 326,000 and "principal investigator" site:ac.uk 236,000. Still say it's not particularly common. Fgf10 (talk) 11:56, 2 January 2016 (UTC)

How many of these pages use the phrase as a formal title, and how many use it as a vague description (like "celebrity")? —Tamfang (talk) 09:30, 2 January 2016 (UTC)

I cannot count them, but many are used like titles: Associate Professor & Senior Scientist, Emeritus Professor and Senior Scientist, Senior Scientist and Director, Name, Senior Scientist, Organization etc. --Leyo 12:40, 2 January 2016 (UTC)

Note that several of those don't seem to be academic ranks but positions or titles outside academia and in fact not all of them are in the UK (although I'm fairly sure the position/title is used in the UK particularly outside academia, the job search for example seem to find some in the UK). Notably, all the senior scientists listed in the last ref are listed under industry, even those at UCB. (Well there is only one, the other is a senior principal scientist.) The second last one seems to be at the at the Museum of Natural Sciences although the person is also at a university albeit with what I assume is a non-teaching position (Research Professor). So while you could say the person is an academic, it's not so clear if the senior scientist position should be considered an academic rank. The other two seem to be clearly academics albeit the senior scientist positions are at a research unit in the university and over clinical trials respectively. Still you could perhaps say these are academic ranks.

Of course this is complicated by the fact that there's no simple definition of an academic, you're likely to get disagreements.

A research associate or fellow at a university is often included even though they have no real teaching (at most they may assist research students in some capacity) with the traditional assumption that they are either going to advance to a teaching position or move away from academia. However someone with a senior research position at an independent institute or particularly a private company is generally not going to be considered an academic, even if they are co-supervising a student. Research professors or similar more terminal research-level positions at universities may also be considered an academic even though their role and job may be fairly similar to someone at an independent institute. (At the very least, it makes sense to list them with other academic ranks.)

Nil Einne (talk) 04:52, 3 January 2016 (UTC)

(EC, written but unsaved a while ago) I'm not sure if just concentrating on it being an academic rank is correct anyway. While some senior scientists may be in academia and in some places it may even be a common academic rank, since it seems to imply a research only role it may be it's not common in certain places like the UK where such roles are uncommon in academia at such a senior level. However there may still be senior scientists outside academia, for example in independent research institutions (private or public) and in private companies. The searches in the UK sort of support the idea this may be where the position is most common in the UK. Nil Einne (talk) 13:27, 2 January 2016 (UTC)

What about a disambiguation then? --Leyo 17:04, 3 January 2016 (UTC)

Disambiguation is to help a reader select among relevant articles. Many medium to large companies with a research and development department have senior scientists, and each company has its own definition of what a senior scientist is, so the term is too diffuse to have a clear meaning that we could write an article about. Thus, there isn't any article to which the proposed disambiguation page could refer the reader. Bear in mind that Misplaced Pages is not a dictionary, so a one-sentence explanation of what a senior scientist is belongs in a dictionary, not Misplaced Pages. Jc3s5h (talk) 17:15, 3 January 2016 (UTC)

There actually is at least one article, List of academic ranks, where Senior scientist is listed. --Leyo 20:37, 3 January 2016 (UTC)

January 2

Identification of little egret's prey

I need help concerning the fish eaten by a little egret in a lagoon near Comacchio.

Could it be a pipefish species? --Leyo 01:30, 2 January 2016 (UTC)

It is a pipefish for sure, probably Syngnathus abaster because its short snout and lagoon environment that are typical for this species common in the north Adriatic sea.--Etrusko25 (talk) 23:04, 3 January 2016 (UTC)

Thank you. Are you sure enough that I may put the photographs into c:Category:Syngnathus abaster? --Leyo 23:22, 3 January 2016 (UTC)

Yes, quite a lot :)--Etrusko25 (talk) 16:00, 4 January 2016 (UTC)

Done, thank you. --Leyo 23:20, 4 January 2016 (UTC)

Name for when a person's face turns red when they are mad

Not blushing necessarily but just when your face turns red in response to anger. Is there a word for this? ScienceApe (talk) 04:00, 2 January 2016 (UTC)

Flushing (physiology) ←Baseball Bugs carrots→ 04:03, 2 January 2016 (UTC)

Both those links say it is called blushing when caused by anger. StuRat (talk) 04:36, 2 January 2016 (UTC)

I've check three dictionaries and they all say blushing is the result of embarrassment, shame, etc but not anger. I normally say flushed with anger.--Shantavira| 10:14, 2 January 2016 (UTC)

You might also consider plethoric - Nunh-huh 10:45, 2 January 2016 (UTC)

Wiktionary lists apoplectic as "effused with blood" and calls it archaic. If the latter, so is my vocabulary. --Cookatoo.ergo.ZooM (talk) 21:23, 2 January 2016 (UTC)

Maybe it's in the specific acception (is that an English word?) of facial color that it's archaic. That is, "apoplectic" is a word in reasonably common contemporary use, but in the sense of "extremely angry", not literally effused with blood. --Trovatore (talk) 21:35, 2 January 2016 (UTC)

Apoplexy is an archaic name for a stroke or cerebral haemorrhage but "apoplectic" still seems to be in use. Richerman (talk) 00:51, 3 January 2016 (UTC)

Come on guys, we can't have archaic and eat it as well... 99.235.223.170 (talk) 01:51, 3 January 2016 (UTC)

You might get more/better answers at the "Language" Help Desk. This question is more about language than science. Just a suggestion. Joseph A. Spadaro (talk) 16:44, 3 January 2016 (UTC)

January 3

Air quality index and highest takes all

According to Air quality index, most of the AQI systems used by governments uses the "highest value takes all" approach, where out of each weighted pollutant concentration, the worst one is selected as the overall AQI and all other pollutants are ignored.

Is there any governmental/supranational institution that doesn't use this approach? I.e. they factor in the lesser pollutants in their AQI instead of dropping them.731Butai (talk) 12:23, 3 January 2016 (UTC)

There have been a wide variety of academic proposals for combined indices, most of which are unsatisfying in one way or another. As far as I know, the only national organization to adopt an approach that is not winner take all is the Canadian AQHI. On the subnational level, Hong Kong also has an approach that combines components . Dragons flight (talk) 12:56, 3 January 2016 (UTC)

Thank you very much again! You've been an awesome help.

I read through the Hong Kong page(), but unfortunately they don't cite any references nor do they clarify exactly how their "Air Quality Health Index" is calculated. Is the Hong Kong AQHI formula the same as the Canadian AQHI formula , which came from this study?731Butai (talk) 13:45, 3 January 2016 (UTC)

That seems to be just a general information page on the general HK government site. Nearly all the links there direct to the main HK government AQHI page, http://www.aqhi.gov.hk. On the main AQHI page, while the "About AQHI" section which is listed under "What's AQHI" tab on the page is somewhat unhelpful ; the method for calculation seems to be listed in the FAQ which also listed under the "What's AQHI" tab on the page. There is also a link to the study they used to arrive at the health risk . Nil Einne (talk) 14:31, 3 January 2016 (UTC)

Thank you! Seems like the Hong Kong formula is based on the Canadian one, and has various additions. This is great stuff. 731Butai (talk) 14:51, 3 January 2016 (UTC)

BTW, the HK study mentions some studies and proposals where amongst other things, combined indices were I think developed but appear to be (from what I can tell, and also what the HK report suggests) largely unused like that for the Cape Town "dynamic air pollution prediction system project" and the Provence Alpes Côte d'Azur Aggregate Risk Index. I presume these are some of the academic examples Dragons flight may have been thinking of. Nil Einne (talk) 15:00, 3 January 2016 (UTC)

Manhunt for suspect in recent TA shooting: Were tracking dogs used? If not why not?

I've seen some criticism of the way police handled the search for the suspect in the recent shooting in Tel Aviv. But one thing I did not see was any mention of tracking dogs. Yet the suspect left a bag in the store next door which I suppose would carry his scent. (You can see the relevant surveillance videos on numerous news sites). So I have two questions: 1. Was this a case where tracking dogs can do the job? (Assuming you know something about tracking dogs and/or have got some sources) 2. If this was such a case, have you seen anywhere any discussion of whether dogs were actually used, and if not, why not? The purpose of this question is more to use a real-life case in order to learn something about the capabilities of tracking dogs than anything else. Contact Basemetal here 17:04, 3 January 2016 (UTC)

I could not find any evidence of tracking dogs being used in this case. Maybe they did use them, but could not get new clues, so it was not worth reporting. Maybe they just assume from the beginning that it was useless. I know that it's easier for a dog to track a human in open nature. A crowded city implies many other human scents as background, which appears to be confusing. It is also useless if the human uses any vehicle to escape or a lift. --Scicurious (talk) 01:01, 4 January 2016 (UTC)

Which is more comprehensive regarding exercise problems? The Feynman Lectures on Physics or Course of Theoretical Physics by Landau & Lifshitz?

75.75.42.89 (talk) 21:15, 3 January 2016 (UTC)

Do you mean Feynman's text itself or including the complementary book of exercises (Exercises for The Feynman Lectures on Physics)? Feynman's Lectures have some exercises for beginners, but they are not enough. And there is also the Feynman's Tips on Physics.

Landau and Lifshitz is a series of rather short works and poor on exercises. There are legal free downloads of them available. So, take a look at them. --Scicurious (talk) 23:30, 3 January 2016 (UTC)

Biology

My biology teacher told the class that he could sit in a bowl of water and suck the water up through his anus via "reverse peristatis" to clean his intestines instead of using an enema. Is this remotely plausible? GrailKun (talk) 22:27, 3 January 2016 (UTC)

Ask him to demonstrate Such a technique is used in yoga and is called jala basti (see this). However it seems you have to use a tube (a bit like you use a straw). If your biology teacher says he doesn't have to use a tube he might be bragging although I can't imagine why anyone would want to brag about something like that. Contact Basemetal here 22:35, 3 January 2016 (UTC)

A case of bragging is one possibility. It's not the first time I hear someone bragging about this ability. Apparently this is something you can be proud of. The wiki article is Basti (Panchakarma)--Scicurious (talk) 23:22, 3 January 2016 (UTC)

I think he probably just wanted to reserve a place for his picture in the dictionary, right next to "over-share." - Nunh-huh 06:47, 4 January 2016 (UTC)

Flatulists draw in air through their anus (prior to expelling it for entertainment purposes), so presumably they can suck in water too.--Shantavira| 10:00, 4 January 2016 (UTC)

In yoga this is called sthala basti. In this case you don't use a tube. Even more impressive. Contact Basemetal here 10:58, 4 January 2016 (UTC)

For all I know next week he'll tell you he can suck the chrome off a trailer hitch. You sure he isn't looking for a date? :) Wnt (talk) 16:19, 4 January 2016 (UTC)

Also, it's a total misconception that intestines need to be "cleaned". Vespine (talk) 22:08, 4 January 2016 (UTC)

Mercury bubble time-of-use meter

I can't find it in the archives, but within the past few months I remember a question about the identity of an electronic component consisting of a small mercury-filled tube with a visual gap in the mercury. While searching for somethign else, I came across our Mercury coulometer article, which does not appear to be linked from the ref-desks. If anyone is still interested in this topic, there's the article. DMacks (talk) 22:29, 3 January 2016 (UTC)

-- Finlay McWalterᚠTalk 22:33, 3 January 2016 (UTC)

Thanks DMacks. I edited that archived section, adding a link to our article. -- ToE 03:13, 4 January 2016 (UTC)

Are you sure it's not a mercury tilt-switch? Those are quite common in all sorts of applications. SteveBaker (talk) 14:20, 4 January 2016 (UTC)

No I remember it too, by "small mercury filled tube", the OP means like that in an old mercury thermometer (the part with the scale). Vespine (talk) 21:59, 4 January 2016 (UTC)

Sharpness of cutting device a physical unit

Is there a physical unit for expressing the sharpness of a knife or it's ability to cut? The article Sharpness is just about a an English port in Gloucestershire and not of much use here. Is the ability to cut just a question of angle and hardness of the blade? --Scicurious (talk) 23:21, 3 January 2016 (UTC)

Lots of many different factors. Here's some:

1) A hard cutting edge.

2) A softer backing material to absorb the force and prevent the cutting edge from cracking (ceramic blades often lack this protection).

3) Thin blade, to reduce drag as it passes through.

4) Weight, to increase the force applied.

5) Length, to allow cutting longer items and get more leverage.

6) Proper care, such as keeping it sharpened and oiled, to prevent rust.

7) A good handle for proper grip.

So, hard to combine all those into a single rating. See Japanese swordsmithing for an example of how many of these factors are maximized. StuRat (talk) 02:07, 4 January 2016 (UTC)

I think most of that list kind of misses the point and specifically, I think the width of the cutting edge is perhaps one of the primary factors to actual "sharpness". Weight, length, care, handle etc are secondary factors to how WELL something can cut perhaps, but not 'sharpness', like a diamond grain is still the HARDEST natural substance, regardless of other factors like how big a scratch it can make, or something. For pure sharpness, you might find Obsidian interesting. In that article it describes the edge as just a few nanometers thick, i suspect if there was a unit for expressing sharpness, it would have been used in this article. Vespine (talk) 03:15, 4 January 2016 (UTC)

And it occurs to me also, just because something is very complex and multifaceted, would do nothing to hinder us making an arbitrary pragmatic scale, such as: "how much force you need to apply to a blade for it to slice through a 10cm cube of ballistic jelly." Not really much different to saying "how much energy it takes to heat up 1 cubic cm of water by 1 Degree". Vespine (talk) 03:21, 4 January 2016 (UTC)

The Japanese used tests just like this. A hair (or was it paper?) dropped on the sword from as close as possible and gets cut with only it's own weight in force is a good sword. They also used things that looked like a reed(?) fasces without the ax about 2 feet wide. Cutting it off in one chop was a sign of sharpness and skill. A rubber band getting cut by the weight of a metal arrowhead without the arrow is a test for deer hunters. Christopher Columbus' men tested sharpness with Indian kid legs and when they got bored they bet on who could cut through a Native American torso with one stroke. Sagittarian Milky Way (talk) 04:19, 4 January 2016 (UTC)

Quite a bit different, actually. For example, how ever much energy it takes to heat 1 cubic cm of water by 1 degree, you can bet it will take twice as much to heat 2 cubic cms, and that the source of the energy won't matter. Not so with a knife cutting through a cube. Also, the optimal angle of attack will vary. For some cutting devices, you push straight into the cube, in others you drag the blade almost parallel to the face, with others in between. The temperature of the blade and cube would also matter, as would how the blade had been sharpened, etc. Testing knives to decide "which is sharpest" would be more like testing cars to see "which is fastest" (where it would depend on track conditions, etc.). StuRat (talk) 04:23, 4 January 2016 (UTC)

You could make a scale as suggested, but I think only for a specific application. I have a friend who is a chef, and his favorite knife of choice is usually a tomato knife as it's better for general purpose cutting than a chef's knife (yes, i was surprised by that), even though it isn't sharp in the way a chef's knife is. So the particular part of the question regarding the ability for a knife to cut must depend on the material you want to cut, and the blade you're going to use, which I think would make it very difficult to specify a definitive unit for sharpness. A bread knife, for example, can easily cut a loaf of bread, and scissors are good for cutting paper, but you couldn't use either any of those tools effectively to perform the other jobs. The 'sharpness' depends entirely on the application. 95.146.213.181 (talk) 05:07, 4 January 2016 (UTC)

You're obviously right in saying that some tasks require a serrated blade, others smooth - and scissors provide a shear force rather than acting as a wedge like a knife. But I don't think that changes the OP's desire to measure sharpness. We're not being asked to measure "cutting power" - which would obviously be unreasonable given the differences in cutting styles. But it doesn't seem unreasonable to ask how narrow the cutting edge is or perhaps what the angle of the wedge close to the cutting edge is...and a handy scale to represent that might be the kind of thing that someone shopping for knives might want to use.

If I was a buyer of knives - it would be nice to know that blade X has a sharpness factor of 5 where blade Y has a sharpness factor of 6 but dulls easily and can only maintain a sharpness of 4 over the longer term.

However, there doesn't seem to be such a scale - so our OP is out of luck here.

SteveBaker (talk) 14:17, 4 January 2016 (UTC)

Microtome might be interesting, and it points out that of course the thinnest blades are only suitable for slicing soft objects so there is a definite difference between sharpness and being able to cut. 14:42, 4 January 2016 (UTC)

This question was asked a a few years ago. ISO 8442.5 is the international standard for kitchen implements. See also this device, a commercial sharpness tester. Tevildo (talk) 17:01, 4 January 2016 (UTC)

January 4

Medication Dose and Weight

In general, do larger adults need higher doses of medication? For example, does someone who weighs 300 lbs need to take more aspirin than someone who weighs 150 lbs in order to get the same therapeutic benefit? I'm not wanting advice about any specific medication: I've always believed larger adults need more (since the adult dose is always higher than the children's dose), but I've never read anywhere that this is really true, and now I'm curious. OldTimeNESter (talk) 12:04, 4 January 2016 (UTC)

There is no uniform answer. Some drugs, such as fat soluble compounds, do need to be scaled accordingly. Other drugs, such as drugs that bind to blood proteins, often don't need be rescaled or would be adjusted by much less than expected based solely on excess weight. Here is a document giving some examples of dosing guidelines for obese patients for a variety of drugs. Dragons flight (talk) 12:40, 4 January 2016 (UTC)

(EC) Body weight and size can definitely be a factors in determining the optimal dose of medication due to differing pharmacokinetics and possibly other reasons. However the relationship is not simple, for example it will depend on the precise drug. Likewise an obese patient may not require the same increase as someone who's larger but not obese, although pharmacokinetics in obese patients is not always as well studied (but for obvious reasons there's increasing interest). Certain drugs have a relatively high therapeutic index and limited side effects so it may be a certain dose works acceptably well for most adults, particularly if only taken for a short time. With others like anti-coagulants and anaesthesia it's generally more important that the dosage is within a fairly narrow optimal range. Also, size and weight aren't the only factors that may need to be considered. See e.g. for some discussion of these factors with various drugs. Nil Einne (talk) 12:55, 4 January 2016 (UTC)

(EC) Maybe in general, I'd say yes, but it's open to so many caveats. The dose of some medications is prescribed related to the size of a person, but even that is a guideline and the titration needs to be adjusted for the individual until the correct level of medication is reached. A 300lb person may need less of a medication than a 150lb person depending on the medication, the individual physiology, metabolism, general health, etc.

Regarding your point of adult vs child doses, there are many other factors other than body size that affect what is safe or effective, such as the ability for a child's relatively undeveloped internal organs to cope with medication (liver and kidneys spring to mind). Gastrointestinal differences between adults and children are significant when taking oral medication such as the aspirin you've suggested. Children take longer to break down oral medication in the stomach (as they have a lower level of gastric acid) and children younger than 6 months also have slow peristalsis, so the medication is absorbed at a relatively slow rate. I'm guessing that's why medication for children is more often in a liquid form, but I'm certainly not sure of that. Conversely children also have elevated metabolisms so for certain types of medication a child may actually need a higher dosage over time than an adult would. 95.146.213.181 (talk) 13:15, 4 January 2016 (UTC)

Thanks, all. It sounds like it's one of those generalities with so many exceptions that it's unwise to rely on it. OldTimeNESter (talk) 23:43, 4 January 2016 (UTC)

Italian scientific journal

A citation in a paper is given as "G.Vicentini & Omodei, Cim. 27, p204, 1899". Presumably "Cim" is an abbreviation of the title of some Italian scietific journal. What is its full title? 120.145.144.103 (talk) 15:50, 4 January 2016 (UTC)

Perhaps Il Nuovo Cimento. Dragons flight (talk) 16:03, 4 January 2016 (UTC)

Yes, and I think the citation is incorrect. The paper at http://www.sciencedirect.com/science/article/pii/S0031891439907032 gives the citation as G. Vicentini, D. Omodei; Nuovo Cim., 27 (1890), p. 204. Looie496 (talk) 16:19, 4 January 2016 (UTC)

Thanks to you both. Googling Vicentini Omodei Cim revealed nothing relavent, but googling Vicentini Omodei Nuovo Cimento revealed the paper at the top of the list. The poster formerly 120.145.144.103 120.145.26.149 (talk) 01:44, 5 January 2016 (UTC)

Are there dozens of models of computational linguistics?

According to xkcd (more exactly ), which is a half-way humorous cartoon but often with a realistic background, there are 12dozens of contradictory models of computational linguistics. Is that just an exaggeration? If not what are the models? Can't you deal with any problem statistically, provided you get enough data and crunching power? --Llaanngg (talk) 16:09, 4 January 2016 (UTC)

The cartoon doesn't say 12, it says "dozens". The reality, I think, is that there are roughly as many models of computational linguistics as there are computational linguists. Looie496 (talk) 16:22, 4 January 2016 (UTC)

OK, dozens not 12. But still, some could be non-contradictory and be grouped together. There is no need to count two slightly different statistical models as two. Otherwise, we get as many models as practitioners in any field. --Llaanngg (talk) 17:39, 4 January 2016 (UTC)

I thought there might be some more information on explainxkcd.com, but there is very little there. AndrewWTaylor (talk) 17:18, 4 January 2016 (UTC)

In the spirit of providing a reliable reference, perhaps some external literary criticism is in order.

That specific comic strip was harshly criticized in one of the early posts on xkcd sucks. The author of xkcd is criticized thusly: "...e's looked to as a bit of an authority in the areas of science; when he says something in the context of science many people will take him at face value. And why not? He has a degree in physics, he's worked in the scientific field; he has experience on his side and many people will trust that experience. As such, he has an intellectual duty to be as straightforward as possible in that regard so as to not accidentally mislead his audience. I'm afraid that many people are going to walk away from this with a misshapen view..."

As much as it may pain readers of xkcd, Randall Munroe is not actually a science and technology expert: he is a professional cartoonist who incorporates themes of science and technology into his comic strip. Most of his readers don't know or notice the numerous technical errors and category errors that appear in the comic.

Strip 114 is a perfect example - which is why it was so called out - because in that work, its author makes a random, non-sequitor claim; munges some technobabble that sounds "nerdy"; and takes an unexpected pot-shot at a fellow cartoonist; and this somehow delights his reader audience, who overwhelmingly perceive the geek-jargon and its non-sequitor conclusion as some form of humor. Meanwhile, educated readers who understand the topic or the references see the strip as "misleading" and "misshapen." This theme occurs so frequently in xkcd that an entire website, xkcdsucks, was set up specifically to call out the strips that partake in this form of non-humor and non-science.

If you're looking for an alternative to Mr. Munroe's very heavily-promoted new book, "Thing Explainer", I would strongly recommend The Way Things Work, by David Macaulay. Macaulay's books are significantly more technically accurate - even when they take artistic license through their characteristic cartoonish flair. In addition to his great artwork, Macaulay's works include some incredible prose and narrative; it's a far shot better than Mr. Munroe's stilted minimalism.

Nimur (talk) 19:35, 4 January 2016 (UTC)

I'm going to avoid the other aspects, but the mention of Ryan North was obviously a bit of good-natured ribbing. xkcd and Dinosaur Comics each link to the other, and Munroe has guest-written for the latter. --71.119.131.184 (talk) 21:39, 4 January 2016 (UTC)

Macaulay's books appear like a good source for a general view of how stuff works. However, it does not seem to enter into computational linguistics models, although I think it deals with some IT topics. Which literature deals with how language can be computed/modelled/processed? That is, where is the bit about dozens incompatible models refuted. Llaanngg (talk) 00:32, 5 January 2016 (UTC)

Computational linguistics from Plato, the Stanford Encyclopedia of Philosophy, reviews the foundations of the discipline and provides a good overview, including a literature survey. Nimur (talk) 01:14, 5 January 2016 (UTC)

Reservoirs are pernicious

In 1837, the Ohio House of Representatives debated expanding a natural lake to form a canal reservoir, and a related document (published on page 390 of the House's journal for that year) concluded by saying:

It may be further observed, that while reservoirs may, to some extent, be pernicious to the health of the adjacent country, yet, in this instance as there would be but little, if any, additional ground covered by converting this lake into a reservoir, there could be no consistent objection made to this arrangement.

Is this referring to the reservoir's potential to produce additional miasma, or are they talking about something else? The idea struck me as rather odd, and if it's not miasma-related, I don't know what to think. Nyttend (talk) 22:26, 4 January 2016 (UTC)

Were they perhaps concerned about Water stagnation? ←Baseball Bugs carrots→ 22:58, 4 January 2016 (UTC)

Ground glass joints with 2.5 bar pressure relief valve?

I have some pretty thick glassware that I am pretty sure will withstand 2.5 atm of internal pressure (one is a sturdy Erlenmeyer flask used for vacuum filtration). I am trying to use this instead of more expensive pressure reactors because I don't really want to pay for a reactor that can withstand 60 bar of pressure (I am not hydrogenating anything -- my sole purpose is to run reactions in dichloromethane at a higher temperature, like 2.5 atm / 70C. 1 atm / 40C is too low) .

I have thought about purchasing made-in-China metal bombs with a pressure capacity of 60 bar, but I wouldn't be able to monitor the reaction, I wouldn't be able to use a magnetic stirbar (I am doing a DCM/water phase transfer catalysis reaction) and I really wouldn't want my reaction to run at 60 bar -- dichloromethane would boil at over 220-250 C (it's off the chart!) and it would basically destroy my sensitive intermediates and products. Or maybe I could use a metal bomb (which are still expensive) with a 2.5 bar pressure relief valve?

if I use a ground glass stopper with silicone grease -- how much pressure would build up inside my Erlenmeyer flask? I have tried looking for ground-glass-to-pressure-relief-valve attachments but I don't think I'm searching correctly. Any insights or possible hacks? Yanping Nora Soong (talk) 22:47, 4 January 2016 (UTC)

Would putting a metal pressure reactor in a water bath be a good moderating idea in place of a customized pressure relief valve? 100C is okay....220 C is way too much. Yanping Nora Soong (talk) 22:53, 4 January 2016 (UTC)

January 5

Fighting fire with fire

When fighting fire with fire, how do they know the right time to ignite the backburn? 2601:646:8E01:9089:5D45:D5AF:855B:E677 (talk) 01:16, 5 January 2016 (UTC)

Where can I find a map of average daily temperature range in the US?

I can't seem to find one. Average seasonal range is easy to find but not average range between a day's high and low. Sagittarian Milky Way (talk) 01:30, 5 January 2016 (UTC)

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