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January 9

Alcohol-based hand sanitizer

Does alcohol-based hand sanitizer lose alcohol content to a significantly degree over time? If so, is it known how fast alcohol content is lost? In a half-used bottle of hand sanitizer, does the existence of a significant volume of air-filled space in the bottle increase the rate of alcohol content loss? --100.34.204.4 (talk) 04:44, 9 January 2017 (UTC)[reply]

If left open, then yes, the alcohol, being more volatile, will evaporate first. But the amount of air in any portion of a sealed bottle won't hold much of the total alcohol volume as partial pressure. I suppose continuously opening the bottle top would allow the alcohol to escape at each occurrence, cumulatively reducing the percentage by a significant amount, but hand sanitizer bottles are typically designed so they don't require that. StuRat (talk) 05:10, 9 January 2017 (UTC)[reply]

Steam locomotive speed

What maximum speed a train hauled by a steam locomotive could attain? --IEditEncyclopedia (talk) 06:09, 9 January 2017 (UTC)[reply]

About 200 km/h (125 mph). See Land_speed_record_for_rail_vehicles#Steam. Notably, the world record holder was going downhill at the time and the engine broke in the process. The level grade record holder is not far behind. Someguy1221 (talk) 06:16, 9 January 2017 (UTC)[reply]

If the "could" is a question about possibility, not historical reality, then I suspect the answer would a lot higher for a purpose-build race machine - I see no particular reason why a train driven by e.g. steam turbine shouldn't be able to beat that. --Stephan Schulz (talk) 08:59, 9 January 2017 (UTC)[reply]

Here is one reason. See Hunting_oscillation. So it could be done but you'd need special rail tracks as well. 196.213.35.146 (talk) 10:18, 9 January 2017 (UTC)[reply]

Yes, but that is not caused by the particular motive force - as the other records show, a conventional train on conventional tracks can go over 300 km/h. --Stephan Schulz (talk) 10:28, 9 January 2017 (UTC)[reply]

The Mallard set a record for steam of 202.58 km/hr (125.88 mph) in July 1938. That record was never broken. Akld guy (talk) 09:19, 9 January 2017 (UTC)[reply]

False precision. The dynamometer-car record was only read in whole miles per hour: that's 126 mph. — Preceding unsigned comment added by 69.159.60.210 (talk) 08:03, 10 January 2017 (UTC) ^{[citation needed]}[reply]

No doubt you have a reference for that claim. Akld guy (talk) 03:02, 12 January 2017 (UTC)[reply]

Classical steam locomotives (reciprocating engine, direct drive) have a very large reciprocating mass. This makes it very hard to have their wheels turn at more than about 10 revolutions per second. To go fast, they need big wheels; Mallard's driving wheels were 6 ft 8 in (2.032 m) in diameter and making them much bigger would be hard and give poor acceleration.

The speed could be increased by, for example, using a steam turbine and electrical transmission and some of these locomotives were indeed build, but the technology only became mature in the 1930s. By then, some countries, like the UK, still tried to push the speed of steam (building locomotives like the Mallard), while others like Germany focussed on diesel-electric propulsion (Fliegender Hamburger) or, like Italy, electric propulsion (ETR 200). Soon it became obvious that the future of fast trains would be electric (although diesel would play a transitional role) and development of fast steam locomotives stopped. PiusImpavidus (talk) 10:24, 9 January 2017 (UTC)[reply]

Also, while steam trains could reach 126 mph, they could only maintain such speeds for a few minutes before things would begin to fall apart -- in fact, during that record run, the Mallard actually suffered a broken big-end bearing and a hotbox (both due to frictional heating of the parts from overspeeding). Diesel and electric trains, on the other hand, could maintain their maximum speed indefinitely as long as the track was clear -- which meant a higher average speed even if the maximum speed was the same. Add to this better low-end torque with the electric transmission (hence better acceleration) and a lower center of gravity (hence higher speeds around curves) and you can see why fast steam trains didn't see any further development. 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 12:50, 9 January 2017 (UTC)[reply]

I remember reading, back in the 1980s when I professionally edited a locomotive-centred publication, that in contrast to Mallard's official record-breaking but somewhat self-destructive run (alluded to by Someguy1221, Akld guy, PiusImpavidus and 2601), contemporary US passenger express locos not infrequently ran at up to 120mph without problems, and could readily have pushed the record beyond that of Mallard had it been desired. I suspect little publicity was sought for these performances because they were probably done unofficially to make up time from late running, and the record was not pursued on either passenger or test runs for fear of frightening off customers. (Sadly, the extensive railway library I built up back then was the property of my employers, not myself, so I have long since lost access to it.) {The poster formerly known as 87.81.230.195} 2.122.62.241 (talk) 23:42, 9 January 2017 (UTC)[reply]

Weeeeellll...it's possible, but since the records don't exist, it's hard to say for certain. The experimental PRR S1 (only one built) was reported in Popular Mechanics to have exceeded 133 mph, and various sources have made claims for speeds as high as 156 mph. The Milwaukee Road class A locos were designed for a cruise in excess of 100 mph and a top speed of at least 120 mph (and probably could do slightly better than that, though again we don't have official records). The Milwaukee Road class F7 locos were even faster and more powerful, expected to exceed 100 mph in daily scheduled service and having been observed at at least 125 mph.

As our article notes, the F7s had to maintain the fastest average speed of any scheduled steam locomotive in history, completing the 78.3 miles between Portage and Sparta (Wisconsin ~~Washington~~) in 58 minutes, for an average stop-to-stop speed of 81 mph. TenOfAllTrades(talk) 22:23, 10 January 2017 (UTC)[reply]

You mean Sparta, Wisconsin -- there's no Sparta in Washington, and the F7s (to my knowledge) were never used on the Olympian Hiawatha (the only Milwaukee train going to Washington). 2601:646:8E01:7E0B:6CD5:FDD3:C2B8:18E8 (talk) 04:00, 12 January 2017 (UTC)[reply]

Yes, definitely. Fixed! I also entirely forgot the PRR T1s, for which there are anecdotal claims of operation at speeds up to 140 mph. TenOfAllTrades(talk) 04:06, 12 January 2017 (UTC)[reply]

There's some mention here [1] of others possibly exceeding the speed. It also mentions how other stuff like DRG Class 05 seems to have come very close. Nil Einne (talk) 15:01, 11 January 2017 (UTC)[reply]

Feynman Lectures. Lecture 6 (6-3, 6-4) [2], Lecture 41 (41-4) [3], Lecture 43 [4]. Probability = 33%

According to the example of Lect. 6 we can calculate the probability of distance after 30 steps with length S_rms=1. The probability to go farther σ = P(D>σ) = $\int _{-\infty }^{-\sigma }p(x)\,dx+\int _{+\sigma }^{+\infty }p(x)\,dx=2\int _{+\sigma }^{+\infty }p(x)\,dx=2\int _{+\sigma }^{+\infty }{\frac {1}{\sigma {\sqrt {2\pi }}}}\,e^{-x^{2}/2\sigma ^{2}}\,dx$ .
For σ=S_rms√30 we have P(D>σ)=0.317.
If the step is fixed as +1 or -1 , then we have the probability = 0.362 JPG xmcd.

According to my previous question [5] if we have e.g. 100 atoms in 100 m³ the probability not to find any atom in 1 m³ = (99/100)¹⁰⁰ = 0.366.

According to Lecture 43 (43-1) the probability that the molecule avoids a collision for a time equal to τ (average time between the collisions) is e⁻¹≈0.37.

Is there any connection between all these probabilities?

Username160611000000 (talk) 11:01, 9 January 2017 (UTC)[reply]

You wrote yourself that one is some value of the error function, another is 0.99^100 and the last is exp(-1). So no.

The closeness of the last two can somewhat be explained by

\lim _{n\to +\infty }(1+a/n)^{n}=\exp(a)

. Tigraan^{Click here to contact me} 16:14, 9 January 2017 (UTC)[reply]

- Thank you very much. Username160611000000 (talk) 18:08, 9 January 2017 (UTC)[reply]

Feynman Lectures. Lecture 43. Ch.43-6 Thermal conductivity [6]

...
The thermal conductivity κ is defined as the ratio of the rate at which thermal energy is carried across a unit surface area, to the temperature gradient:

${\frac {1}{A}}{\frac {dQ}{dt}}=-\kappa {\frac {dT}{dz}}.$ (43.41)

Since the details of the calculations are quite similar to those we have done above in considering molecular diffusion, we shall leave it as an exercise for the reader to show that

$\kappa ={\frac {knlv}{\gamma -1}},$

— Feynman • Leighton • Sands, The Feynman Lectures on Physics, Volume I

Using arguments of Ch. 43-5 I try next: $J={\tfrac {n_{\text{hot}}\cdot v_{\text{hot}}\Delta T-n_{\text{cold}}\cdot v_{\text{cold}}\Delta T}{\Delta T}}$

If . . $n_{\text{hot}}=n_{\text{cold}}=n$ . . we have $J=n(v_{\text{hot}}-v_{\text{cold}})$

$-(v_{\text{hot}}-v_{\text{cold}})={\tfrac {dv_{a}}{dx}}\Delta x={\tfrac {dv_{a}}{dx}}\cdot 2l$

${\tfrac {d(v_{a})^{2}}{dx}}\sim {\tfrac {dT_{a}}{dx}}$

$m{\tfrac {d(v_{a})^{2}}{dx}}=3k{\tfrac {dT_{a}}{dx}}$

$m{\tfrac {2vdv_{a}}{dx}}=3k{\tfrac {dT}{dx}}\Rightarrow {\tfrac {dv_{a}}{dx}}={\tfrac {dT}{dx}}\cdot {\tfrac {3k}{2mv}}$

$\therefore J=n(v_{\text{hot}}-v_{\text{cold}})=-n{\tfrac {dv_{a}}{dx}}\cdot 2l=-n{\tfrac {dT}{dx}}\cdot {\tfrac {3k\cdot 2l}{2mv}}$
$=-{\tfrac {dT}{dx}}\cdot {\tfrac {3nkl}{mv}}=-{\tfrac {dT}{dx}}\cdot {\tfrac {3nkl{\tfrac {v}{2}}}{mv{\tfrac {v}{2}}}}.$
$J\cdot {\tfrac {mv^{2}}{2}}=-{\tfrac {dT}{dx}}\cdot {\tfrac {3nklv}{2}}$
$J\cdot {\tfrac {mv^{2}}{2}}={\tfrac {dN}{dt}}{\tfrac {1}{A}}\cdot {\tfrac {mv^{2}}{2}}={\tfrac {dQ}{dt}}{\tfrac {1}{A}}$

$\therefore {\tfrac {dQ}{dt}}{\tfrac {1}{A}}=-{\tfrac {dT}{dx}}\cdot {\tfrac {3nklv}{2}}$ .

$(\gamma -1)=2/3$

Is it correct ? I'm not sure that in 1-dimentional case we can write mv²=3kT. For 1 degree of freedom we have 1kT.

Username160611000000 (talk) 18:05, 9 January 2017 (UTC)[reply]

Why are the leaves still red?

In January, a tiny plant in my yard still has red leaves. They look like maple leaves, specifically the Acer pseudoplatanus photo with that article, and there are maple trees across the street. However, full-size trees have pretty much lost their leaves, or at least the ones left on trees have turned brown. This plant, a couple of inches tall, is even red below the leaves (the "trunk"). I never saw that.— Vchimpanzee • talk • contributions • 22:11, 9 January 2017 (UTC)[reply]

Were the leaves green before? Apparently the color leaves turn depends on what was in them when the chlorophyll dies off, apparently red leaves have left over "food" in them while brown leaves are more depleted. Vespine (talk) 22:43, 9 January 2017 (UTC)[reply]

A further possible factor: being so small, the plant may be in a more benign microclimate than the conditions to which nearby full-sized trees are overall subject. The article Deciduous may point to some clues as to why your yard-sheltered plant is privileged.

Re the trunk/stem, I've casually noticed myself that some saplings tend to have thinner bark containing a degree of chlorophyll, as contrasted to more mature specimens of the same species, so the sapling's bark can be expected to emulate the leaves' colour changes. {The poster formerly known as 87.81.230.195} 2.122.62.241 (talk) 23:55, 9 January 2017 (UTC)[reply]

There are a number of maple cultivars that have red leaves year round, see for example the later parts of Acer palmatum article. If it has red leaves year round then it may be either one of those, or a natural mutation. Watch that plant for a few years, and see if the trait was transient or persists. Dr Dima (talk) 03:07, 10 January 2017 (UTC)[reply]

Poinsettias are prized for that behavior. StuRat (talk) 04:21, 10 January 2017 (UTC)[reply]

Ah, but the red bits of a poinsettia are bracts rather than leaves. Alansplodge (talk) 13:03, 11 January 2017 (UTC)[reply]

From our article: "a bract is a modified or specialized leaf". StuRat (talk) 16:34, 11 January 2017 (UTC)[reply]

New shoots of many plants are red. As TPFKA says, trees do slightly different things based on their age/height/microclimate/position in the canopy. Generally speaking, understory deciduous temperate trees will have both earlier bud break and keep their leaves longer. This change in phenology is thought to take advantage of the extra light before the canopy_(biology) closes and after it has left in the autumn. Here is a really great freely accessible article on the topic: Differences in leaf phenology between juvenile and adult trees in a temperate deciduous forest Augsperger and Bartlett (2003). All this is to say: it is perfectly reasonable to expect to see seedlings/saplings keep their leaves longer than their full-sized peers. SemanticMantis (talk) 17:24, 10 January 2017 (UTC)[reply]

Update: I forgot about this when it snowed. Now that the snow has melted, the leaves are brown and have fallen off, and the "trunk" is turning brown as well.— Vchimpanzee • talk • contributions • 21:54, 13 January 2017 (UTC)[reply]

Where can you drive through a redwood?

I didn't find anything on Wikipedia using the normal methods, but Chaz Henry on KKOV says you can't do it any more. A storm has knocked down that tree. I don't know who Chaz Henry is because he never identifies his employer, but sources for this should be easy to find. However, I don't know what Wikipedia article would require updating.— Vchimpanzee • talk • contributions • 22:13, 9 January 2017 (UTC)[reply]

That would probably be the Pioneer Cabin Tree in Calaveras Big Trees State Park. This tree has been all over the local news in Northern California. For example: Remembering California’s storm-toppled historic Pioneer Cabin Tree (from the San Jose Mercury News, January 8, 2017).

I think I mentioned earlier this weekend about how bad the weather was - it's been really wild out there!

Nimur (talk) 22:53, 9 January 2017 (UTC)[reply]

Interested readers, see also: the Wawona Tree and the rest of the trees on the list of largest giant sequoias; and the Chandelier Tree, which is a close relative, a Coast Redwood. Nimur (talk) 22:56, 9 January 2017 (UTC)[reply]

One thing I haven't seen with the pictures that were published: did the Pioneer Cabin Tree crack at the height of the car tunnel? I'm thinking that digging a tunnel through a sequoia may be cool for a hundred years, but in sequoia terms, it's pretty much a killing blow? Wnt (talk) 00:20, 10 January 2017 (UTC)[reply]

Comparing these two pics, taken from near the same vantage point (note the large block of wood on the right side), it looks like it fell backwards from its burn-marked side and the top part of its roots ripped out. One problem with sequoias is that they don't have a particularly sturdy root system. [7][8] ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:24, 10 January 2017 (UTC)[reply]

There are several drive-thru trees in the Redwood Forest in far Northern California. [9] Killiondude (talk) 01:02, 10 January 2017 (UTC)[reply]

Our article links to Chandelier Tree but mentions it is a "coast redwood not a giant sequoia". (Also mentioned by Nimur above.) Looking at the above list, the species isn't mentioned. A quick search didn't find the species for the other two, so I stopped looking. I get the feeling they're probably coast redwoods though. Nil Einne (talk) 06:08, 10 January 2017 (UTC)[reply]

A simple search finds [10] appears to be the person you're referring to but I'm not sure the relevance of his identity to the question. Nil Einne (talk) 05:11, 10 January 2017 (UTC)[reply]

He wouldn't be the only news source reporting this, so it's not that important. We could assume others reported the same tree.— Vchimpanzee • talk • contributions • 16:15, 10 January 2017 (UTC)[reply]

Not sure why there's need to assume anything. Nil Einne (talk) 19:14, 10 January 2017 (UTC)[reply]

As for giant sequoias tunneled through, see this page. --69.159.60.210 (talk) 08:08, 10 January 2017 (UTC)[reply]

Engineering question: fit, clearance and tolerance

In reference to something written here (but copied and pasted here), I wonder how to consider this because, in my mind, I've got it backwards:

"When two parts are to be assembled, the relation resulting from the difference between their sizes before assembly is called a fit. A fit may be defined as the degree of tightness and looseness between two mating parts."

The important terms related to the fit are given below:

Clearance

In a fit, this is the difference between the sizes of the hole and the shaft, before assembly, when this difference is positive. The clearance may be maximum clearance and minimum clearance. Minimum clearance in the fit is the difference between the maximum size of the hole and the minimum size of the shaft.

Interference

It is the difference between the sizes of the hole and the shaft before assembly, when the difference is negative. The interference may be maximum or minimum. Maximum interference is arithmetical difference between the minimum size of the hole and the maximum size of the shaft before assembly. Minimum interference is the difference between the maximum size of the hole and the minimum size of the shaft."

I have underlined the part that I don't understand and italicized the corresponding part that I do understand. In terms of what I do understand, interference is when there is what we'd colloquially refer to interference; in other words, item X interferes with item Y. So minimum interference would be a maximum hole and a minimum shaft attempting to pass through that hole. But what I don't understand is why minimum clearance is maximum hole with a minimum shaft attempting to pass -- to be, this seemed to provide the maximum (magnitude of) clearance as 'clearance' is understood colloquially. I suppose it could be a typo, but more likely, I speculate it's merely some mathematical convention of assigning clearance with a negative, and so it's the inverse of what may appear to make sense colloquially -- or perhaps I've just got it more wrong than I think. Thanks to whomever is able to help. DRosenbach ^{(Talk | Contribs)} 23:23, 9 January 2017 (UTC)[reply]

I agree that Minimum clearance in the fit is the difference between the maximum size of the hole and the minimum size of the shaft seems to be a lazy cut and paste. perhaps they just meant maximum. Greglocock (talk) 06:34, 10 January 2017 (UTC)[reply]

I also agree. The source of the error is Indira Gandhi National Open University whose website provides no general e-mail address, only telephone numbers. (One might try contacting directorsoss@ignou.ac.in). Someone near New Delhi could inform IGNOU politely that the mistake in their course material needs correcting. Blooteuth (talk) 12:47, 10 January 2017 (UTC)[reply]

You are right, they meant to write "maximum clearance in the fit". Clearance is positive, there is no weird sign-flip convention. Here is a more clear definition of min/max clearance, with a worked example [11]. Here [12] is another definition of "clearance", which is synonymous with the maximal clearance of the previous ref.

I'm not an engineer, but I'd think relevant definitions of clearance should be added to Engineering_tolerance. Engineering_fit uses the categorical notion of "clearance fit", but does not give any info on clearance as a quantity.

Perhaps this use of min/max clearance is slightly deprecated, but persistent? Because the quality and number of references is surprisingly low... SemanticMantis (talk) 15:47, 10 January 2017 (UTC)[reply]

January 10

Feynman Lectures. Lecture 43. Lecture Summary [13]

...
${\text{The current of particles / area sec.}}=-{\frac {1}{3}}lv{\frac {dn_{a}}{dx}}=-\mu kT{\frac {dn_{a}}{dx}}=-D{\frac {d}{dx}}({\frac {n_{a}}{n_{0}}})$

— Feynman • Leighton • Sands, The Feynman Lectures on Physics, Volume I

Can you show how did he get ${\frac {n_{a}}{n_{0}}}$ ? In Lecture 43 he wrote $D={\tfrac {1}{3}}lv$ , $D=\mu kT$ , but never $D=\mu kT\cdot n_{0}$ . Username160611000000 (talk) 09:43, 10 January 2017 (UTC)[reply]

How is gluten-free flour made?

How is gluten-free flour made? Since gluten is supposed to give bread its shape and structure, do gluten-free products taste as good as the traditional wheat/barley/rye products? Also, since some people eat gluten-free because of health risks of eating gluten-laden foods, can they just switch to rice? The gluten-free diet article just points out that wheat/barley/rye contains gluten, not rice or cauliflower (which can be made into a rice-like powder) or quinoa. 66.213.29.17 (talk) 17:54, 10 January 2017 (UTC)[reply]

It's as you say: gluten-free flour is made from gluten-free plant species [14] Dr Dima (talk) 19:04, 10 January 2017 (UTC)[reply]

Gluten-free bread is a huge area of research! You can find information on the rheology of GF bread, crumb characteristics, moisture, and many other aspects of many formulations. You can even see images from scanning electron microscopy, and analysis of loss modulus (e.g. [15]). Anyway, as for the taste: nothing beats some personal experimentation, as taste is somewhat subjective. However, we do have scientific research on that as well:

"Breads with legume flours showed good physico-chemical characteristics and adequate sensory profile" [16].

"Panellists commented that this bread "looked more like real bread" and that the loaves had "loaf volume and crust color similar to wheat bread" [17] SemanticMantis (talk) 20:07, 10 January 2017 (UTC)[reply]

Without gluten you need a substitute to hold the bread together. Eggs are one option. See [18]. StuRat (talk) 23:12, 10 January 2017 (UTC)[reply]

Is it scientifically proved that menstruation causes women to be irritated or nervous or it's a myth?

If it's true, then what is the physiological / psychological (psychophysiological) explanation for that? 93.126.88.30 (talk) 20:03, 10 January 2017 (UTC)[reply]

See premenstrual syndrome, and the second reference cited there [19]. Here are a few relevant scholarly references as well [20] [21]. There is much variation in the mood and affect of individual women during different phases of the menstrual cycle, but real changes in mood (and hormones, and physiology) do occur. SemanticMantis (talk) 20:17, 10 January 2017 (UTC)[reply]

On a related topic, at one time it was commonly asserted that PMS had a strong 'nurture' component and that women who experienced difficulty did so largely due to seeing other females having difficulty (i.e. that is was largely psychosomatic). If there's any doubt about that not being the case, this 2014 study states outright that there is "a clear genetic influence in premenstrual syndrome." Matt Deres (talk) 01:24, 13 January 2017 (UTC)[reply]

Earth Axis Axial Precession

I have a question about the Wikipedia article on Earth axis axial precession. This article depicts this precession as going in a counter-clockwise direction as projected on the celestial sky. But an Astronomy Online article depicts this precession as going in a clockwise direction on the celestial sky. Which is correct? Jfandrus57 (talk) 21:59, 10 January 2017 (UTC)[reply]

Some diagrams can be ambiguous, but I think our article is correct. Which article shows it clockwise? Dbfirs 22:31, 10 January 2017 (UTC)[reply]

By way of an independent confirmatory source, I have here A Field Guide to the Stars and Planets, 1964 edition by Donald H. Menzel. On page 330 is a diagram showing the north celestial pole precessing anticlockwise against the fixed stars, the same as is shown in this section of the Wikipedia axial precession article (and the dates in the diagrams also agree).

Side comment: on first viewing the top diagram in that article, my initial reaction was that it showed precession going the other way. Once I thought about it I realized that this is because when it draws a reference circle to illustrate the precession, it's shown from the other side, looking toward the Earth rather than toward the stars. Nothing's ambiguous there, but I did find it misleading and I wonder if it might be better to substitute a different diagram or else add some words of explanation. --69.159.60.210 (talk) 05:39, 11 January 2017 (UTC)[reply]

January 11

Physicists vs. Mathematicians

Am I the only one finding the new proposed redefinition of SI base units utterly hilarious ? I just can't help but chuckle when I think about what would happen if mathematicians were to convene one day and utter sentences like: ``One, 1, is the unit of numbers; its magnitude is set by fixing the numerical value of the Archimedes constant π to be equal to exactly 3.1416`` — I mean, seriously !? 79.113.235.103 (talk) 05:31, 11 January 2017 (UTC)[reply]

I don't know, I've seen some intensely complicated definitions of 1 coming from mathematicians. Someguy1221 (talk) 06:49, 11 January 2017 (UTC)[reply]

Probably categorists. --Trovatore (talk) 08:38, 11 January 2017 (UTC) [reply]

Well, just look at the Principia Mathematica by Alfred North Whitehead and Bertrand Russell, which defines basic arithmetic in terms of extremely detailed symbolic logic and a kind of variant of set theory. Famously, it takes hundreds of pages to reach a proof that 1 + 1 = 2. Smurrayinchester 08:46, 11 January 2017 (UTC)[reply]

Actually, the International Union of Pure and Applied Physics really did suggest in 1999 that the number 1 should become an SI unit under the name "uno", with symbol U: it's still on their website archives here. The idea was to make it easier to express dimensionless quantities in a less language-dependent way; so instead of saying "5 parts per million" (5 ppm), you'd say "5 microunos" (5 μU). The response to it was overwhelmingly negative and the idea was scrapped. As for defining 1, I think a simple enough definition would be "1 is the multiplicative identity". Double sharp (talk) 09:14, 11 January 2017 (UTC)[reply]

Not so easy, as typically multiplication is defined in terms of addition, so you need addition first. There are constructions of the natural numbers, with 1 being defined as the successor of 0. I'm sure that the friendly people at Wikipedia:Reference desk/Mathematics could tell us a lot about this. --Stephan Schulz (talk) 15:00, 11 January 2017 (UTC)[reply]

Indeed, complications arise very quickly: even in commonplace applications. For example, how is the multiplicative identity defined in non-commutative algebras? You use those every time you use matrix multiplication - and that shows up in basic tasks in elementary engineering and physics! If we define "one" as "the multiplicative identity," then our definition confusingly requires equality between the scalar value and every instance of the identity matrix. This is just one example of the semantic problem of a simple definition - we could work around it by re-defining "one" or by re-defining "multiplication" - but no matter what we try, we end up complicating the overly-simplistic original definition! Nimur (talk) 16:04, 11 January 2017 (UTC)[reply]

I think Double sharp meant something like "the one of the real numbers" or "the one of the natural numbers". There is no particular need to identify these across different structures, unless you're considering these as some embedded in others, or as embedded in some common larger structure.

There are certain structures where it is usual to identify values with their images under the canonical embeddings: Naturals -> rationals -> reals -> complex numbers, for example. We don't ordinarily distinguish between the zero of the natural numbers and the zero of the real numbers. However, when these structures are given concrete definitions in terms of set theory, the zero of the natural numbers is strictly speaking a distinct object from the zero of the real numbers. --Trovatore (talk) 20:17, 11 January 2017 (UTC)[reply]

Indeed that is what I meant, which proves that I am clearly not the one to write legalese definitions. I'm aware that strictly speaking, 1 as a natural number is different from the ⁠11⁠ it is constructed as as a rational, and however one chooses to define 1 based on one's preferred construction of the real numbers for whatever purpose one has at the moment. Still, they all act the same way, so perhaps a little ambiguity is fine here. Perhaps "1 is the multiplicative identity of the real numbers" might work, although I rather like (in hindsight) how my original vague definition justifies the use of 1 to symbolise the multiplicative identity of any multiplicative group or unitary ring. It probably needs some more work, though. Double sharp (talk) 07:42, 12 January 2017 (UTC)[reply]

My main point of contention was the awkward `rationalization` of certain physical constants. Like forcing them onto some Procrustes bed, and shaving off their decimals. (This makes some sense when it comes to the definitions of the meter, second, and candela, because at least there we have some relatively-nice integers, but it becomes tiresome when exaggerated). Then again, by trying to make those weird `rational` values nicer, we only end up modifying the values (and nice properties) of the units in question (like the Kelvin and the kilogram). — 86.122.66.160 (talk) 19:32, 11 January 2017 (UTC)[reply]

I don't think "nice properties" really count for much. Units are arbitrary and any set is as good as any other. You have to keep track of a few constants, but you're always going to have to do that. Computers don't mind, and humans mind only to the extent they do mental arithmetic with the values, which is not a very large extent in the first place, but to the extent that it does matter, you can't optimize for one area of endeavor without de-optimizing for another.

The point of the proposed SI redefinition is to get rid of reliance on artifacts once and for all. That's a worthy goal. They've chosen to do that in a slightly roundabout way (fixing the values of fundamental constants by definition, instead of expressing the units as products of powers of the fundamental constants). This approach is reasonable, in my opinion, because it's easier to see, oh right, Planck's constant is what I want it to be. I don't see anything hilarious about it. --Trovatore (talk) 20:03, 11 January 2017 (UTC)[reply]

There's also an important different between pi and, say, the speed of light. Pi is a mathematical constant, and its precise value can be calculated to as many digits as you like by mathematical methods. You can't change the value of the pi within the framework of fundamental axioms of mathematics (and if you do change these, you get some kind of Non-Euclidean geometry). The speed of light on the other hand is a physical constant - we can't simply derive its value from first principles, but instead have to make a measurement somewhere. There will always be uncertainty in those measurements, and in all measurements - including the ones you use to define your units (a big problem they found when using old physical prototypes is that replicas differed by miniscule amounts). What the redefinition does is recognize this and embed this uncertainty in the definition of the units themselves, rather than in the measured physical constants. Smurrayinchester 09:41, 12 January 2017 (UTC)[reply]

Why does capital punishment have to be by lethal injection in the US?

All these problems with getting the lethal drugs, why not just put the prisoner to sleep then cut off the oxygen supply? Quick, easy and painless, or am I missing something? 2.102.186.137 (talk) 07:56, 11 January 2017 (UTC)[reply]

[1] capital punishment does not have to be by lethal injection in the U.S. The laws of the states or federal laws, depending on the jurisdiction prosecuting the crime, set forth the acceptable methods of execution.

[2] in 2014, Tennessee introduced death by electrocution as an alternative to lethal injection if the necessary drugs cannot be found.

[3] in 2015, Oklahoma introduced death by nitrogen gas as an alternative to lethal injection if the necessary drugs cannot be found. (similar, but not identical to your method)

[4] in 2015, Utah introduced death by firing squad as an alternative to lethal injection if the necessary drugs cannot be found.

[5] all of the 32 states that have the death penalty in 2017 permit execution by lethal injection. 8 states permit execution by electrocution, 11 by gas chamber, 3 by hanging, and 2 by firing squad.

In short, the legislatures legislate the methods of execution, and none have authorized your suggested method. - Nunh-huh 08:27, 11 January 2017 (UTC)[reply]

Funnily enough, our article on cruel and unusual punishment#Capital punishment does discuss this as a possibility. As far as I can tell main problem is basically that so far, it hasn't been used. Therefore, if a criminal was sentenced to death by inert gas asphyxiation, they could go to court arguing that it was cruel and unusual (in violation of the Eight Amendment). It's therefore easier to just a technique that the courts have already allowed, even if it is a horrible approach. Oklahoma recently made this their back-up technique - if lethal injection is banned, they will start using that instead. Smurrayinchester 08:56, 11 January 2017 (UTC)[reply]
- Asphyxiation in a pure nitrogen or argon atmosphere is not really cruel. It might actually be rather enjoyable for the victim, given the feeling of euphoria it can induce. Double sharp (talk) 10:22, 11 January 2017 (UTC)[reply]
  - Sure, but you would probably have to prove that in court since there's no precedent for its use. Courts already allow lethal injection, so it's the easier option. Smurrayinchester 11:04, 11 January 2017 (UTC)[reply]

Indeed, the bar is not whether you or I think something is "cruel and unusual." In the United States, the policy is for the court with appropriate legal standing to make such a determination. Law of the United States is a good introduction. Most schools in our country teach the very basic concepts to all students in some form of a civics class; over the next several decade, mass-media tries to un-teach those basics by blasting abject nonsense at the citizenry. My most pointed example is the apparent refusal of most media outlets to reference American laws by their actual, correct names.

On the other hand, our president-elect has, just this morning, made a public statement suggesting that our national system of government is similar to Nazi Germany... I really cannot fathom how he expects us, the informed citizens, to parse this statement. So what do I know?

Nimur (talk) 16:31, 11 January 2017 (UTC)[reply]

For the record, the tweet-quote is: Intelligence agencies should never have allowed this fake news to "leak" into the public. One last shot at me.Are we living in Nazi Germany? (punctuation error in the original) Tigraan^{Click here to contact me} 17:52, 11 January 2017 (UTC)[reply]

Note that as hinted by the two respondents above, simply cutting off the oxygen supply isn't as simple as it sounds. In addition, depending on how you do it, it's not clear if it won't be felt if the person isn't sufficient unconscious. As mentioned above something like inert gas asphyxiation may be relatively painless but it's unclear if this is what you mean when you refer to cutting of the oxygen supply.

More to the point, if your proposal requires putting the person to sleep (I assume you mean rendering them unconscious), you've potentially defeated the purpose of what you're trying to achieve. As our article Lethal injection mentions, the drug that's most problematic to obtain is often an effective general anaesthesia. Although these by nature can also be used in single drug protocols or as part of the lethal component in multi drug protocols, if specificallly lethal components are used, these are often not so hard to obtain. Especially potassium chloride.

You need to redesign your protocol to avoid the need to put the person being executed to "sleep" before administring the lethal part. Which inert gas asphyxia potentially achieves but simply cutting of the oxygen supply somehow may not do so, if you haven't considered how you would do so and how the body will respond.

Nil Einne (talk) 14:46, 11 January 2017 (UTC)[reply]

I've always thought an overdose of insulin would be the way to go. It causes lethargy, mental confusion, then they pass out, then they die. People who almost died from overdoses of insulin didn't report any pain. And, if for some reason it needs to be reversed, like the proverbial last minute call for the governor, you can inject a glucose solution to counter it. StuRat (talk) 16:28, 11 January 2017 (UTC)[reply]

I've always thought that getting rid of the death penalty, like nearly all civilised societies have done, would be the way to go. --Stephan Schulz (talk) 18:21, 11 January 2017 (UTC)[reply]

It's a noble theory. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:35, 11 January 2017 (UTC)[reply]

This is not the first time I heard people call shitting on the graves of murder victims "noble" and "the way to go", but that doesn't make it any less wrong! 2601:646:8E01:7E0B:6CD5:FDD3:C2B8:18E8 (talk) 02:20, 12 January 2017 (UTC)[reply]

Note I said "theory". Nations have the right to permanently rid themselves of evil individuals. Some choose to keep them alive, some don't. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:05, 12 January 2017 (UTC)[reply]

Nations have the right to permanently rid themselves of evil individuals. - presumably you meant states rather than nations, and "the right" is a disputable choice of words here. The notion that a state has a moral right of life or death on its citizens is, let's say, controversial. Tigraan^{Click here to contact me} 12:30, 12 January 2017 (UTC) [reply]

There are federal laws allowing for capital punishment for certain federal crimes. The individual US states also have their own laws allowing (or not) capital punishment for certain state-level crimes. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:51, 12 January 2017 (UTC)[reply]

My meat was with the word "right". Most sovereign states have a process to pass pretty much any law if enough people in the decision centers agree (excluding international treaties, maybe), so it has all imaginable "rights" in the meaning of "legal possibility to do X". But "right" also means a moral justification. In pretty much every developed country, there is a significant minority (>20%) or even a majority that thinks death penalty is not "right". The distinction is fairly old. Tigraan^{Click here to contact me} 17:08, 12 January 2017 (UTC)[reply]

Maybe you'd prefer saying that governments have the power to impose the death penalty. As to whether it's morally "right" or not, that's a long-debated issue. But the US Constitution allows for it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:18, 12 January 2017 (UTC)[reply]

Unless the state makes the victims itself. Bazza (talk) 12:22, 12 January 2017 (UTC)[reply]

Massive insulin overdose might do the trick, but [1] it may cause seizures, and unattractive deaths will be militated against, and [2] it's slow, and [3] it might fail, leaving neurological damage but no death. As much as 50% of the time. And no one really knows what dose is enough to cause death because it will vary greatly. - Nunh-huh 06:59, 12 January 2017 (UTC)[reply]

Your links are missing. As for the dosage, as long as a large enough dosage will do it, we don't need to know the precise dosage needed for each individual. StuRat (talk) 16:25, 12 January 2017 (UTC)[reply]

Well, there is some interesting reading at [22], [23], and [24]. And yes, we need to know how lethal a chemical is before using it to kill people, so we need to know the dosage. - Nunh-huh 22:25, 13 January 2017 (UTC)[reply]

Michael Portillo presented a BBC Horizon program on TV about this . Nothing difficult - he even underwent the lose of consciousness bit himself. v=DiEJKvbpOF0. The big problem with hanging, electric chair and gas chambers is that it upsets the witnesses to the execution. Unfortunately LI does not work to well on IV drug addicts that have damaged veins, so process can be even more protracted and distressful.--Aspro (talk) 19:49, 11 January 2017 (UTC)[reply]

There's not really much science here - killing people can be pretty low-tech. I imagine a classic Wile E. Coyote 20 ton weight would do the job quite convincingly. Also see suicide methods, as a society agreeing on means of execution is technically making a suicide pact. I think the politics should be evaluated in terms of the rational self-interest of the individual "execution experts" who sometimes make a decent living providing specialized skills and hard to get substances to those whose regulatory decisions mandate their use. Ethics is profit, profit is ethics, the rest is just words. Wnt (talk) 21:25, 12 January 2017 (UTC)[reply]

Why is a cocktail of drugs used?

My understanding of killing humans by lethal injection is that a cocktail of drugs is used. Why is this? I worked as a veterinary nurse to pay for me to go to university and I have witnessed many animals being euthanased. It is a simple injection of just one drug and it is so quick the animal often appears unconscious before the injection has been completed, and there never appears to be any distress. If a state must have capital punishment for humans, why can this drug not be used? DrChrissy ^(talk) 23:24, 11 January 2017 (UTC)[reply]

How do you know it was just one drug? Do you have the name of it?--86.187.171.92 (talk) 23:36, 11 January 2017 (UTC)[reply]

My personal experience having pets euthanized is that it has always been two drugs. First a sedative to knock the animal out, then a lethal dose of a barbiturate. I've seen laboratory mice, however, euthanized with just an overdose of the sedative. Someguy1221 (talk) 23:54, 11 January 2017 (UTC)[reply]

e/c Apologies. My writing above was a bit sloppy. I meant a single injection. My understanding is that humans are killed by 3 injections given sequentially which causes death over a period of time (please correct me if I am wrong). The drug I have used is lethabarb which contains pentobarbitone sodium. The article Pentobarbital has some related information including the killing of a human prisoner by a single injection of the substance. DrChrissy ^(talk) 23:57, 11 January 2017 (UTC)[reply]

@Someguy1221 There are reasons why a sedative might be given first. Some animals do not like the handling associated with intravenous injections. The vet may have given the sedative (usually an intramuscular injection which can be given extremely quickly) to calm the animal for the following intravenous injection for euthanasia. This is particularly likely if you asked to have your pet euthanased whilst you were present. No vet wants an animal to freak out at such an emotional time. Where in the world do you live? - there may be different laws on euthanasia of pets? DrChrissy ^(talk) 00:07, 12 January 2017 (UTC)[reply]

Have you read Lethal_injection#Drugs ? Not sure the question is directly answered, but it has relevant information. Vespine (talk) 00:40, 12 January 2017 (UTC)[reply]

Thanks for this. Yes, I have actually just finished reading it. The article states that several US states (11 I think) do use a single injection. Maybe I am just catching up with US legislation, but it seems to me to be such an inhumane approach to use a method that might take several hours to kill a human when there is a method out there that does this in seconds - I am not condoning capital punishment in the slightest, but if a state elects to do this, it should be humane. DrChrissy ^(talk) 00:48, 12 January 2017 (UTC)[reply]

Religious/political/moral pontificating is out-of-scope. DMacks (talk) 05:25, 12 January 2017 (UTC)[reply]

Come on, Dylan Roof deserves to die. Humanely of course. Sagittarian Milky Way (talk) 02:50, 12 January 2017 (UTC)[reply]

Dylan Roof deserves to die, this is an opinion, not a fact. I personally think that it isn't humane to kill people at all, even if they have committed atrocious crimes. It's either "vengeance" which I don't believe in, or "punishment" which I don't believe either. I don't believe in an afterlife, so killing someone is actually closer to "letting them get away with it" than even letting them serve a jail sentence. And I live in Australia where we don't have capital punishment and there's no real evidence whatever that capital punishment is a deterrent to criminals. The ONLY valid reason I have heard for capital punishment is that it is cheap, since housing a criminal in prison with no chance of rehabilitation for the rest of their life is very expensive, and that money is better spent on people who aren't criminals. I actually agree with that reason, I would rather feed hungry children than incarcerate terrible criminals, but to a society that is a FAR harder "sell" than just saying it's a punishment. This does not even go into the REAL reason for my belief which is more about free will, but that gets very philosophical very quickly and this is not the place for a debate about opinions so I'll leave it at that. And before you try to straw man my argument, I do not at all believe people should be allowed to do anything they want or not face dire consequences for their actions, I just don't think that we as a society have actually worked out what those "dire consequences" should be, but I am quite certain killing people ain't it. Vespine (talk) 03:53, 12 January 2017 (UTC)[reply]

"He that smiteth a man, so that he die, shall be surely put to death"; "And he that stealeth a man, and selleth him, or if he be found in his hand, he shall surely be put to death"; "But whoso shall offend one of these little ones which believe in me, it were better for him that a millstone were hanged about his neck, and that he were drowned in the depth of the sea" -- God's own words regarding the death penalty! 2601:646:8E01:7E0B:6CD5:FDD3:C2B8:18E8 (talk) 04:14, 12 January 2017 (UTC)[reply]

The economic argument doesn't really hold water either, actually. Death penalty cases are significantly more expensive to prosecute than non-death-penalty cases (due to everything from extra time to death-qualify jurors, to the additional trial time for the death penalty phase, to extra trial motions and appeals) [25]; in Oregon, for example, it costs about an extra million bucks just to decide to kill a defendant. Death row inmates are also appreciably more expensive to house prior to their execution, which adds a hefty ongoing cost. A sentence of life without parole actually works out, on average, to be less expensive than a death sentence. TenOfAllTrades(talk) 04:24, 12 January 2017 (UTC)[reply]

Only because of crooked lawyers abusing the process, not because of the nature of the death penalty itself! 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 05:06, 12 January 2017 (UTC)[reply]

Roof wants to die as a martyr for his wretched "cause". While legally he might deserve death, it would be a better punishment if he were kept alive, surrounded by prisoners of different ethnic groups for the rest of his miserable life. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:08, 12 January 2017 (UTC)[reply]

Note that this isn't restricted to lethal injections for capital punishment. As our article mentions, multiple drug protocol lethal injections are sometimes used for voluntary euthanasia or assisted suicide. I'm not really sure what your experience is but if it's primarily with companion animals, an obvious consideration is that what works well for a 5kg cat or a 40kg dog may not work well for a 100kg human. Some dogs can exceed 100kg but these are rare so I wonder how likely it is you've experienced euthanasia with such an animal.

Our article does mention it often isn't so simple with large animals although I think it's mostly talking about significantly larger than the average human. In any case, even with similar body weights, human physiologies and metabolisms are different so there's still no guarantee it's going to work the same.

In addition, I think it's clear that "appears to be painless" and "whops that didn't work as planned" is far less accepted with humans. Also with the death penalty, assisted suicide and some forms of voluntary euthanasia there's less room for the involvement of competent medical personnel if it doesn't seem to be going as planned or especially for the death penalty, even from the beginning.

Maybe a key point is that it's not entirely clear whether the old protocol, which after all is not that dissimilar from some euthanasia protocols, is really that bad if properly administered. The cases with the old protocol that cause concern often seem to be cases where something went wrong, especially failure to to maintain an IV site or perhaps administering the wrong amounts or at the wrong time. It seems to be the newer protocols developed due to the unavailability of drugs, that are more questionable. (This is not to suggest the single drug protocol developed without consideration of drug availability is flawed. Although I think it's also clear one reason why old protocols are maintained is because they seem to generally work, it's difficult to develop new protocols given the problem of getting competent people to do it and as mentioned above there is also the risk the new protocols may be delay things due to challenges etc even if they are better.)

Although I probably should mention that as our article states, there are those who do question whether either the single drug or multiple drug protocols do actually always work as claimed even when properly administered, but this gets back what I said earlier namely that it's not clear if thing are different with other animals.

Nil Einne (talk) 06:27, 12 January 2017 (UTC)[reply]

BTW I should clarify I'm not in any way dismissing concerns over the three drug protocol. As our article mentions one key concern is the effect of the typical additional drugs (well I don't know if I'd really call potassium chloride a drug but I digress), as they may help induce death but it's not clear whether they help with the painless etc part. So if the sodium thiopental does fail, you may still kill the person but perhaps not so painlessly. Note however the Ohio single drug protocol only uses 2.5x the typical dose for the three drug protocol [26] and our article seems to imply the same amount can be used.

This and the fact some voluntary euthanasia or assisted suicide protocols use different drug combinations indicates that it's an area of active debate. Two obvious key differences between voluntary euthanasia or assisted suicide and the death penalty are that with the former, the person should have made a conscious decision to accept there's a risk something may go wrong and there may be pain (and they may already have worse pain anyway) or they may wake up alive. And that carries to the second, with voluntart euthanasia or assisted suicide when they wake up it's not ideal for anyone, but they will hopefully just want to try again. Whereas with the death penalty the person who may not want to die, wakes up alive but has to accept they're still likely to be killed at some stage.

One final comment is it would seem possible to use some voluntary euthanasia or assisted suicide protocols for the death penalty to help with the problem of how to develop these (although developing these can be contentious too). However I can't seem to find much evidence this has ever really been done, probably politicial it's problematic and as per the earlier point you'd need to defend these protocols and even if they've been developed by hopefully competent medical personel, they're not going to help you in court.

Nil Einne (talk) 12:56, 12 January 2017 (UTC)[reply]

I'm not entirely sure I'm convinced by the size argument. Great Danes typically weigh 50-82 kg - the weight of a woman or man. To me, it would seem that increasing the volume and/or concentration of the barbiturate would solve any size/weight-related problem. Having said this, our Animal euthanasia article states some veterinarians consider the volumes required for large animals (horses and cows) to be problematic, and use drugs other than those used on cats and dogs. In looking at this, I have noticed that there very well may be a difference between UK and US approaches, with the US approach being to use 2 injections whereas the UK favours 1 (see [27]) DrChrissy ^(talk) 21:06, 12 January 2017 (UTC)[reply]

But how many Great Danes did you witness being euthanised? Note also, even without different physiologies from being different animals, you can't assume that simple increasing the amount means something is going to work the same with something as complicated as anaesthesia. In other words, if for example, something is borderline for a 60kg dog, increasing the amount given doesn't mean it's going to work properly on a 100kg dog. And yes the problem with larger animals as mentioned in our article is something I explicitly mentioned. BTW your source does mention one thing I suspect but wasn't sure namely that the same key problem with humans can occur with other animals namely inability to access a vein. That's also mentioned here [28]. This [29] mentions a personal story of such a problematic euthanasia. This [30] does sort of suggest unsurprisingly that competence can play a big part (but unlike with the death penalty it shouldn't be hard to find a vet to perform the euthanasia although in cases of high volume like animal shelters I'm not sure if this is always done). I suspect the same for here [31]. Of course even with a vet involved [32] it's not guaranteed nothing will go wrong. (And I think experience outside the death penalty tells us that IV access problems in humans aren't always to do with competence.) Nil Einne (talk) 01:12, 13 January 2017 (UTC)[reply]

Well actually, I have been involved in the euthanasia of several large dogs, including Great Danes. I used to be responsible for the overnight intake of accidents and emergencies. I was never instructed not to use Lethabarb on heavy dogs. What are the physiological differences you elude to above? DrChrissy ^(talk) 20:19, 13 January 2017 (UTC)[reply]

I think the main appeal of the cocktail of drugs idea was that one part can "accidentally" be left out or be ineffective while the rest works, ensuring that the patient would be paralyzed and in agony while not actually being anaesthetized. Remember, execution protocols are not being pitched to normal people, they're sold to killers. However the "Ohio protocol", introduced after complaints, somewhat ameliorates that (I think in part by having more anaesthesia and in part by retrograde amnesia from the midazolam, just in case!). Having multiple tubes to watch also increases the ooh-la-la factor and gives more of a sense of a solemn ceremony than if you just hit the guy over the head a couple of times with a big hammer. Wnt (talk) 21:31, 12 January 2017 (UTC)[reply]

So you think people are doing this during voluntary euthanasia or assisted suicide too? Note as I said above, more anaesthesia is actually only 2.5x at most of a dose which is already generally considered sufficient to kill provided it goes in properly (which may be a big if in some cases but highlights the fact it's not entirely clear if the increase in dosage is actually doing anything useful), but possibly less than a 2.5x increase of a dose Nil Einne (talk)

Lethal_injection#History explains how we came to use the "three-drug cocktail" for lethal injections. The State of Oklahoma's Medical Examiner, working with an anesthesiologist at the state medical school, developed the first legal definition for execution by lethal injection: "An intravenous saline drip shall be started in the prisoner's arm, into which shall be introduced a lethal injection consisting of an ultrashort-acting barbiturate in combination with a chemical paralytic.". This evolved into the current "three-drug cocktail - that short-acting barbiturate first, then a paralytic agent, usually pancuronium bromide to depolarize the skeletal nerves and thus stop the prisoner's respiration, then a cardioplegic agent, potassium chloride, in sufficient quantity to stop the patient's heart muscle.

I'd like to say here that the last two steps of the procedure probably are pretty painful. My wife's brother was accidentally given potassium chloride intravenously during a procedure, went into asystole, and described it as excruciatingly painful. Since the consequence of injection with pancuronium bromide without active mechanical ventilation is also that your heart muscle stops because it's not getting oxygen from your lungs, that hurts like hell, too. You just can't scream because your lungs don't work, and you can't writhe in agony because none of your other skeletal muscles work.

Truly humane lethal injection would involve a lethal dose of a very potent opiate agonist like etorphine (used in veterinary medicine as "Immobilon" to rapidly sedate very large animals such as elephants). The median lethal dose of etorphine in humans is 30 micrograms - you can literally nick yourself with a needle contaminated with etorphine and die quickly if the antidote isn't given quickly just after you do. The problem with this is, like phenobarbital, no one in the US makes etorphine at this time. And, like phenobarbital, the US could get its supplies of etorphine cut off if the overseas suppliers (the UK and Germany) learn it's being used for execution by lethal injection. But in the current political climate, it's possible an enterprising chemist could get a permit from the Drug Enforcement Administration to manufacture etorphine in the United States to allow states to execute prisoners humanely (etorphine intoxication would be very humane, you fall asleep, then your breathing stops and you die of heart failure while still deep asleep). loupgarous (talk) 09:39, 13 January 2017 (UTC)[reply]

Thanks very much for this. I had noticed that potassium chloride was used for elephants (after the elephant is first unconscious)[33]. Is there a physiological reason for different drugs being used on different species of mammals? I would have thought their physiology was sufficiently similar (including humans) that "one drug suits all"? (By the way, this is rather good article on animal euthanasia [34]) DrChrissy ^(talk) 19:43, 13 January 2017 (UTC)[reply]

Follow up: I have just read "Potassium chloride injection is not a method that is generally used in routine pet euthanasia; it is typically used in the euthanasia of horses whereby there is the possibility for the horse's meat to enter the food chain (meat that contains barbiturates is lethal to other animals that eat it)" [35]. So, potassium chloride (and possibly other non-barbiturates) might be used for large animals (including wildlife) where other animals may eat them. DrChrissy ^(talk) 20:25, 13 January 2017 (UTC)[reply]

Answering your question, different species have different responses to different sedatives, and this influences the method of euthanasia, along with economics and legal constraints. Animals whose flesh is to be eaten (horses are often butchered and/or rendered to recover meat, fat, and other valuable by-products, for example) are either shot, killed or stunned by a blow to the skull by a large hammer or a captive bolt "stunner", killed by exsanguination or electrocution or knocked down by administration of potassium chloride (I hesitate to call any of those methods "euthanasia" as all entail pain to the animal). You're right that barbiturates, opiate agonists and other more humane euthanasia agents are avoided when the animal's meat is to be consumed. The meat packing industry uses captive bolt stunners, electrocution or sledgehammers with rapid exsanguination by slicing major arteries open to slaughter animals. loupgarous (talk) 21:33, 13 January 2017 (UTC)[reply]

I work for a university on animal welfare science so I am well aware of the range and effectiveness of methods used in the commercial slaughter of animals. I am more interested in finding out what are the physiological differences between mammals that apparently cause these differences in reactions - even apparently as an editor indicates above, differences within the same species (dogs). DrChrissy ^(talk) 21:45, 13 January 2017 (UTC)[reply]

Does an increase in your heart rate result in greater thirst on your part?

Does an increase in your heart rate result in greater thirst on your part? Also, if so, does this result in you becoming dehydrated if you don't increase your water intake? Futurist110 (talk) 23:04, 11 January 2017 (UTC)[reply]

Didnt know you could insure against your heart rate. Anyway this is a medical question that WP dont answer.--86.187.171.92 (talk) 23:34, 11 January 2017 (UTC)[reply]

I obviously meant "increase" here--not "insurance." Futurist110 (talk) 00:50, 12 January 2017 (UTC)[reply]

We don't have a policy against medical questions, we have a policy against medical advice. This doesn't seem like a request for medical advice to me. I do however think the question is malformed, I don't think increased heart rate results in greater thirst, not directly anyway, those two things are unrelated. Thirst is a response to dehydration, not a response to increased heart rate. If you increased your heart rate by doing exercise which involved sweating, that will increase your thirst but again, that's a result of hydration, not heart rate directly. Anaerobic exercise can greatly increase your heart rate for short periods of time without significantly affecting your hydration or thirst. So it's not really clear what the OP is asking imho. Vespine (talk) 00:36, 12 January 2017 (UTC)[reply]

You might also just in general be interested in reading our article on thirst. It does not mention increased heart rate at all. Vespine (talk) 00:42, 12 January 2017 (UTC)[reply]

It might be better to give a simpler physiological explanation. If the increase of heart rate is due to anxiety or fear, the sympathetic nervous system becomes dominant. Chewing and digesting food is less important than escaping from that threat (during which the parasympathetic nervous system becomes less dominant) . To escape from such a threat (real or imaginary) the available body fluids needs to be available for the muscles. Therefore, the secretion of saliva stops (which regulated by the parasympathetic). Tachycardia does not increase thirst on its own. Once the threat subsides, the saliva flows again without the (urgent) need for re-hydration. --Aspro (talk) 14:33, 12 January 2017 (UTC)[reply]

Decimal years

In scientific journals, what does a duration of (for example) "17.8 years" mean? Is it 17 years and 8 months, or is it 17 and 8/10 years? --2606:A000:4C0C:E200:C03A:9D20:31EF:82F7 (talk) 23:57, 11 January 2017 (UTC)[reply]

In astronomy it is often the Julian year, 365.25 days times 17 and 8/10ths. Sagittarian Milky Way (talk) 02:44, 12 January 2017 (UTC)[reply]

If they're using base 10, .8 is

{\tfrac {8}{10}}

. I don't doubt that some people mistakenly use .8 when they mean 8 months out of 12—which is two-thirds, or

.{\overline {6}}

in base 10—but I would hope scientists pay more attention to using the correct figures. --47.138.163.230 (talk) 04:21, 12 January 2017 (UTC)[reply]

Thanks. The reason for my uncertainty is that I have seen dates formatted with periods (dd.mm.yyyy), so it could follow that a period be used as a year & month delimiter. --2606:A000:4C0C:E200:C03A:9D20:31EF:82F7 (talk) 05:40, 12 January 2017 (UTC)[reply]

No. The dates and periods are two completely different things. — 86.122.66.160 (talk) 11:20, 12 January 2017 (UTC)[reply]

January 12

Zeroth

I heard he had sa law, but who was Zeroth?--86.187.171.92 (talk) 00:42, 12 January 2017 (UTC)[reply]

It is "0^th" -- referencing thermal equilibrium in zeroth law of thermodynamics. --2606:A000:4C0C:E200:C03A:9D20:31EF:82F7 (talk) 01:02, 12 January 2017 (UTC)[reply]

...Actually, it precedes the first law of thermodynamics. --2606:A000:4C0C:E200:C03A:9D20:31EF:82F7 (talk) 02:01, 12 January 2017 (UTC)[reply]

Well, we were going to call it the Noughtth law but the spellchecker wouldn't let us. It is a bit of a conceit, basically the First Law was well known and then some smarty realised that there was a more fundamental law that needed to be established first. So it got named the First-1 law, ie Zeroth Law. Greglocock (talk) 05:24, 12 January 2017 (UTC)[reply]

When they come up with the "negative oneth law", it will be even sillier. StuRat (talk) 16:17, 12 January 2017 (UTC) [reply]

Am I missing something? How do we know OP is talking about thermodynamics? Maybe they are asking about the zeroth law of robotics or the the laws of zeroth order logic? Those are both mentioned at the 0th page. SemanticMantis (talk) 16:29, 12 January 2017 (UTC)[reply]

Also used in chemical kinetics, i.e. zeroth order. --Jayron 32 16:44, 12 January 2017 (UTC)[reply]

That Zeroth is a real Renaissance man. ;) --2606:A000:4C0C:E200:C03A:9D20:31EF:82F7 (talk) 17:07, 12 January 2017 (UTC)[reply]

Are you thinking about Zeno of Elea and Zeno's paradoxes? Graeme Bartlett (talk) 22:53, 13 January 2017 (UTC)[reply]

Extra credit

If somebody came up with a law more fundamental than the 'Zeroth Law', what would they call it? --2606:A000:4C0C:E200:C03A:9D20:31EF:82F7 (talk) 18:18, 12 January 2017 (UTC)[reply]

Whatever they chose to. Like if Joe Green came up with it, they might call it Joe Green's Law. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:26, 12 January 2017 (UTC)[reply]

Leonard Susskind proposed a "Minus First Law" (since he considered it more fundamental than the zeroth law) which is "Bits cannot be destroyed". Some consider it a corollary of the second law, and not a proper law of its own. A few sources use "Negative First Law", but Susskind used "Minus First Law". See here for Susskind's own formulation. --Jayron 32 18:34, 12 January 2017 (UTC)[reply]

Wire gauges went from 0 to 00 to 000 to 0000. Negative numbers are also possible. Or, at some point one needs to just abandon the system and come up with a new one. Switching to A, B, C, ... would avoid confusion with the old numbering system. But, personally, I don't think numbering laws is a good idea. We should refer to them by names instead, so laymen have a clue what we're talking about. Which makes more sense, "Einstein's law of general relativity", or "physics law #28" (if it were called that) ? StuRat (talk) 18:39, 12 January 2017 (UTC)[reply]

A, B, C only works until they have to switch to "before A", and then eventually they drop classifications other than the multiple A's, i.e. minor league baseball. --Jayron 32 21:09, 12 January 2017 (UTC)[reply]

This happened with US household battery sizes, too. Yet another reason not to assign numbers or letters to such laws at all. StuRat (talk) 03:49, 13 January 2017 (UTC)[reply]

Bird hipped and reptile hipped

My son and I are reading a National Geographic book. In the section on dinos, there is reference to bird hipped and reptile hipped dinos. The artical then goes on to say that modern birds are more closely related to the reptile hipped dinos than the bird hipped. 1) in what way is this so? 2) if birds are more closely related to the reptile hipped dinos, how can they have evolved from bird hipped dinos? — Preceding unsigned comment added by 76.71.158.242 (talk) 02:21, 12 January 2017 (UTC)[reply]

The articles are at Ornithischia and Saurischia. Sagittarian Milky Way (talk) 02:58, 12 January 2017 (UTC)[reply]

Ichthyornis is one of the closest animals to full bird. It too evolved from lizard-hipped dinosaurs. (not a bird ancestor, just a cousin) Sagittarian Milky Way (talk) 03:57, 12 January 2017 (UTC)[reply]

To answer the question, see convergent evolution. That two different, unrelated groups develop similar structures through evolution is well documented. I.E., whales and fish have both evolved fins, but whales did not get those fins because they evolved directly from fish. Similar things happened between birds and ornithischia; the hip structure in birds evolved independently, but along similar patterns, as did that of the ornithischians. --Jayron 32 13:31, 12 January 2017 (UTC)[reply]

For point 2) it is not correct to say that birds evolved from bird-hipped dinos. Origin_of_birds explains that modern birds are a group of theropod dinosaurs. All theropods are part of the Saurischia group linked above. So it is not correct to say that birds evolved from bird-hipped dinos. It is correct to say that birds are theropods, and evolved from earlier lizard-hipped (i.e. Saurischia) dinosaurs. The book is trying to explain that just because the bird-hipped dinos are called "bird-hipped", we should not assume that modern birds are descended from or most closely related to them. Hope that helps, SemanticMantis (talk) 15:18, 12 January 2017 (UTC)[reply]
The "bird hipped" description of the Ornithischia is an old one (1880s), from visual observation of similarities in shape. Although it's later than the discovery of Archaeopteryx (1860s), it also pre-dates the notion that birds evolved from dinosaurs at all. At the time, Archaeopteryx was described (by Darwin) as a "strange bird" and was seen as an ancient bird of unknown origin, not as an evolution from the dinosaurs.

Later work, based on far more specimens and better techniques, such as cladistics, for recognising lineage of evolution showed that the birds are now thought to have arisen from the sauropod dinosaurs (i.e. lizard-hipped), not the bird-hipped. Convergent evolution gives a similar shape in later generations. To further confuse it, we also see early bird-hipped dinosaurs like Psittacosaurus (it even means "parrot lizard") which are now thought to have been partially covered with bristles, a structure resembling feathers (despite being far older than Archaeopteryx and having no relation). Andy Dingley (talk) 17:46, 12 January 2017 (UTC)[reply]

Saurischia (and more specifically therapoda, not sauropod. Sauropods are the long/neck tail dinosaurs like Brontosaurus. 86.177.146.201 (talk) 22:13, 13 January 2017 (UTC)[reply]

Why do nurses remove bubbles from syringe before injection to IM?

Why do nurses remove bubbles from syringe before injection to IM (intra-muscular)? I do understand why they do that before injection to IV or Intra-artery, because it can cause to air embolism but I don't understand what can be in case of injection to IM.93.126.88.30 (talk) 04:06, 12 January 2017 (UTC)[reply]

Same reason -- air bubbles anywhere within a person's body can cause an air embolism! 2601:646:8E01:7E0B:6CD5:FDD3:C2B8:18E8 (talk) 04:16, 12 January 2017 (UTC)[reply]

Oh nonsenese. if you have been on IV for any number of days you'll have lots of little bubbles injected into you. Greglocock (talk) 05:26, 12 January 2017 (UTC)[reply]

1) Habit. 2) As part of measuring the correct dose (if there is a bubble in the syringe, then the markings on the syringe barrel will overstate the volume of medication).

That said, for some intramuscular injections, a small amount of air – after the medication – is sometimes deliberately injected to help trap the medication in the tissue: [36].

As an aside, it's actually relatively difficult to cause a fatal air embolism by intravenous injection. While not recommended, tiny bubbles injected IV will almost always be trapped in the lungs (and fairly rapidly dissipate). (Our article on air embolism mentions this.) TenOfAllTrades(talk) 04:37, 12 January 2017 (UTC)[reply]

How long does the air stay there? Does it dissolve in the capillary blood and go out the lung? Sagittarian Milky Way (talk) 01:31, 13 January 2017 (UTC)[reply]

then the OP's answer is incorrect ("Same reason -- air bubbles anywhere within a person's body can cause an air embolism!"). Is it right? 93.126.88.30 (talk) 04:50, 12 January 2017 (UTC) [reply]

[Point of clarification: you, 93.126.88.30, are the OP (Original Poster), while 2601:646:8E01:7E0B:6CD5:FDD3:C2B8:18E8 is an IP poster.] {The poster formerly known as 87.81.230.195) 2.122.62.241 (talk) 10:38, 12 January 2017 (UTC)[reply]

Regarding reason #2, only if the air-bubble is pushed out of the dead volume. Even if you push the plunger all the way into the barrel, there is some internal space remaining in the Luer taper or other plumbing and the needle itself. If the syringe were at volume-marking 0 and you pull up to 1 mL with the needle in a liquid, pushing the plunger back to 0 expells 1 mL no matter what the dead volume had been. But, if you hold the syringe at any angle other than needle-straight-down, the bubble that represents the original dead volume might get expelled instead of that equivalent volume of liquid. So if you make sure there are no bubbles, the angle does not matter (trade-off of wasting the dead-volume-worth of liquid). DMacks (talk) 04:45, 12 January 2017 (UTC)[reply]

Note that an injection intended to be intramuscular may accidentally hit a vein or artery. Not very likely, but it would be nice not to kill the patient when it happens. StuRat (talk) 16:20, 12 January 2017 (UTC)[reply]

If you hit a vein or artery when trying applying an intramuscular injection, you would cause a bruise if you retract it without injecting it. But if you do apply it anyway, a little air bubble is just a small problem compared to the fact that you are injecting a medication through the wrong route.Hofhof (talk) 17:52, 12 January 2017 (UTC)[reply]

That depends on the med. A local anesthetic could cause death if injected into the wrong vein or artery, but some other meds would just be ineffective if so injected. StuRat (talk) 18:29, 12 January 2017 (UTC)[reply]

The article air embolism in the relevant part of it, is with a lot of "citation needed", then it's very dificult to relay on it. 93.126.88.30 (talk) 20:55, 12 January 2017 (UTC)[reply]

But the key part mentioned by DF above which contradicts part of what StuRat has said is supported by this ref [37]. This ref [38] used to support the info on arterial embolisms also supports the info on veneous air embolisms. Nil Einne (talk) 01:55, 13 January 2017 (UTC)[reply]

Who is DF and what part contradicted what I said ? StuRat (talk) 03:52, 13 January 2017 (UTC)[reply]

Possible meanings for DF. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:58, 13 January 2017 (UTC)[reply]

Let's say that he meant to Dear Friends... anyway, these sources don't mention the entering of gas to the artery through the periphery (and that's what relevant to our discussion) but through central places. 93.126.88.30 (talk) 04:18, 13 January 2017 (UTC)[reply]

But I wasn't commenting on arterial air embolisms other than to say the source used does support the claim made in our article, and also supports the claim made about venous air embolisms. Nil Einne (talk) 12:23, 13 January 2017 (UTC)[reply]

BTW I came across [39] which isn't an RS although it does link to a bunch of them. The author clearly doesn't agree with current practices and beliefs about the lack of harm from air in IV lines. But it's also clear that they're talking about significantly more air then the ~~small~~ bubbles that may be present in syringe used for intramuscular or IV injection ~~(unless someone majorly screwed up)~~ and even there the actual danger isn't so clear cut (i.e. it's not going to definitely cause death) hence why the author has to argue for changes to current practices of ignoring significantly more air in IV lines than what we're talking about. (Reading a bit more, possibly it's easier to get larger bubbles in syringes than I expected, so I've changed my reply, but this doesn't change the relatives difference between the amount of air in syringes and that is apparently accepted for IV lines.) Nil Einne (talk) 12:42, 13 January 2017 (UTC)[reply]

In case there's still doubt, some more discussion here [40] from nurses suggesting that while practices vary, often up to 20ml of air is ignored. This is mostly with IV lines, discountinf the 1 odd case where a nurse injected 20 ml of air. Also perhaps [41], [42] and [43]. As far as I can see, while it's still recommended to avoid air bubbles with IV injections both for dosage reasons and just because it's considered practice, the actual evidence it's likely to cause death unless you have massive bubbles isn't there. Nil Einne (talk) 13:44, 13 January 2017 (UTC)[reply]

Sorry I meant TOAT. For some reason I thought it was Dragonsflight who made the above comment. TenOfAllTrades specifically said "actually relatively difficult to cause a fatal air embolism by intravenous injection" before your reply, and this is indeed supported by the article TOAT linked to with references and contradicts your suggestion that the presence of ~~small~~ air bubbles in the syringe (if these are not pushed out) means there's a good chance of causing death if you nick a vein. Nil Einne (talk) 12:23, 13 January 2017 (UTC)[reply]

I didn't say "good chance". Even if the chance was only 1 in a million, if nurses stopped worrying about air in the syringe, that would still likely result in thousands of deaths a year, not to mention other lesser complications. So, it's worth the effort to remove the bubbles. StuRat (talk) 21:11, 13 January 2017 (UTC)[reply]

January 13

Is there something like a reactivity series for melting points of organic compound types?

So at least the more important kinds are ranked like organic acids, normal 2-ketones, n-alkanes, n-alkenes, n-alkynes, n-alcohols, n-aldehydes, n-perfluoroalkanes, maybe n-cycloalkanes and so on? Then pick whatever number you want like butyl or dodeca- and all the melting points will be ordered? And one for boiling points if it's different?

If this isn't possible then is there a graph with dots or lines for the n-alkanes, n-alkynes and so on? Sagittarian Milky Way (talk) 00:14, 13 January 2017 (UTC)[reply]

What you want is a specialized application of the Unified Physicochemical Property Estimation Relationships (UPPER) model developed at the University of Arizona College of Pharmacy. It's described in detail by its developers Bo Lian and Samuel Yalkowsky in the document Unified Physicochemical Property Estimation Relationships (UPPER) (which, uncharacteristically for an Elsevier title, is available outside a pay wall). Figure 4 on Page 2714 is the graph "Calculated versus experimental total entropy of melting ( ): Walden’s rule; ( ): line of identity; N = 352."

Akash Jain, also of the University of Arizona College of Pharmacy, created a more detailed document "ESTIMATION OF MELTING POINTS OF ORGANIC COMPOUNDS" as his PhD dissertation. Luckily for you, that's free, too, courtesy of the University of Arizona College of Pharmacy. Most of the information you're looking for is tabular, not graphic, in Jain. The graphs in the document are almost all the observed vs. predicted melting points for organics.

I hope this helps. It's probably not the cut-and-dry thing you were asking for, you'll have to scan or key the tabular values in to get any graphs not provided by the authors. Increasing knowledge is increasingly expensive. loupgarous (talk) 02:10, 13 January 2017 (UTC)[reply]

(edit conflict) Comme ci? --Jayron 32 02:12, 13 January 2017 (UTC)[reply]

Comme ça. Sagittarian Milky Way (talk) 18:12, 13 January 2017 (UTC)[reply]

What are the borders of the cerebral circulation?

When talking about the pulmonary circulation then its borders are very clear, since that it starts in the heart (to be accurate in the beginning of pulmonary artery in the heart) and ends in the beginning of pulmonary vein in the heart. But when talking about cerebral circulation it's not clear to me what are the borders of the vascular. I found on Google that it's "starts from the muscular carotid and vertebral arteries, which bring oxygenated blood the brain, and ends with jugular veins", but I don't know if it's reliable or not. In addition according the article here (cerebral circulation) there are two circulations, that actually makes it "cerebral circulations", anterior and posterior. 93.126.88.30 (talk) 03:48, 13 January 2017 (UTC)[reply]

There's also the Circle of Willis which consists of communicating arteries which can shunt blood flow between the posterior and anterior circulation and the blood vessels supplying each side of the brain. This tends to prevent ischemia of an area of the brain to which direct flow of blood is blocked; blood can flow through the communicating arteries of the Circle of Willis from patent arteries in some cases to perfuse areas of the brain to which direct arterial blood flow's been interrupted. This doesn't happen in all cases. loupgarous (talk) 21:44, 13 January 2017 (UTC)[reply]

How could air embolism in the artery (by syringe) cause heart attack or stroke?

1) I've been reading very well the article here on "air embolism" , and it's not clear to me how can a bubble that inserted by syringe to the artery of the arm, reach to the heart or the brain and damage them. the blood flow is just in opposite direction (from the heart to the tissue in case of artery). 2) In addition, why the bubble (air) is not dissolved in the blood? 3) Those bubble that we are talking about in the context of air embolism they are with the composition of the air outside? (78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases) 4) The article here states: "Gas embolism into an artery is a more serious matter than in a vein, because a gas bubble in an artery may directly stop blood flow to an area fed by the artery.", I don't understand the statement that support in the claim that the Artery gas embolism is more serious than in vein, because we can say that the same thing can happen with bubble in veins that the bubble can stop the blood floe to an area that drown by the vein, such in case of DVT. 5) It's written also that in case of vein embolise in the most of the cases it's stopped in the lung. what does it mean "stopped"? does it mean that it goes out by diffusion or it's stuck there? 93.126.88.30 (talk) 05:15, 13 January 2017 (UTC)[reply]

Same way that an air lock in a fluid line happens -- the bubble reaches a local high point and gets stuck there (because air is lighter than blood), and interrupts the blood flow. 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 06:26, 13 January 2017 (UTC)[reply]

From the hand to the heart or brain? In addition, unlike a fluid line, the artery has a pressured flow toward the opposite direction, as noted. 93.126.88.30 (talk) 06:59, 13 January 2017 (UTC)[reply]

Your car's gasoline line is also pressurized, but that doesn't mean an air bubble can't cut off the fuel flow to the engine if the conditions are right! 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 07:13, 13 January 2017 (UTC)[reply]

The article on that is air lock, and it explains that "circulating pumps usually do not generate enough pressure to overcome air locks". Now normal systolic blood pressure is about 120 mm Hg, which means it's enough to raise a column of mercury 120 mm. Now compared to blood, mercury is about 12.8 times as dense, so that pressure would lift blood by more than 1.5 meters—which makes sense in view of where the blood has to go to circulate. That sounds to me as though it should overcome an air lock all right—but of course that pressure won't apply everywhere in the body. There must be places where the pressure is lower and which are therefore more vulnerable. --69.159.60.210 (talk) 09:31, 13 January 2017 (UTC)[reply]

The reason why air bubles in the fuel line of a car can stop fuel flow is NOT because the pump cannot develop enough pressure to overcome it. The pressure is what it is. It is because when the air bubble reaches the pump, the pump is sucking against air and not fluid. Fluid is not compressible or expandable, but air is. As most car fuel pumps are reciprocating, the inlet valve closes at the end of each pump stroke before the expanding bubble clears the valve. I too have noticed nurses getting air bubbles out of syringes, and thought I knew why. But then my wife had a lot of chemo delivered by IV into a vein, and the nurses pretty much ignore air bubbles, unless they stop the IV pump pumping, in the same way as air can stop a car fuel pump pumping! The quick-connect plumbing they use for chemo pretty much guarantees a few air bubles each time. 121.221.103.89 (talk) —Preceding undated comment added 09:59, 13 January 2017 (UTC)[reply]

Then the air lock article needs to talk about air bubbles reaching pumps. It doesn't now. --69.159.60.210 (talk) 00:06, 14 January 2017 (UTC)[reply]

And since the heart is also a reciprocating pump, if you get a big enough air bubble inside it, you'll stop the heart as well by the same mechanism! 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 13:26, 13 January 2017 (UTC)[reply]

True, but the size of the air bubble big enough to stop heart pumping would have to be the ENTIRE volume of a LARGE syringe, even allowing for expansion at the heart intake pressure. The millimeter size bubles you get in syringes and IV tubing is at least 2 orders of magnitude below that. Also the heart is a 2-stage pump. It is inconceivable that one air bubble could stop pumping in both sides. 121.221.103.89 (talk) 15:51, 13 January 2017 (UTC)[reply]

I lost it through the reach discussion. I still don't understand how it can arrive from the arm artery to the heart or brain against the flow. What did I missed? (In addition the articles that were mentioned here are talking about insertion of bubble very close to the ares of the heart or the brain) 93.126.88.30 (talk) 18:37, 13 January 2017 (UTC)[reply]

Sleep-wake in DSM

The DSM is a "Diagnostic and Statistical Manual of Mental Disorders" (my emphasis).

It includes a great deal on sleep-wake disorders. Why? I assume that it's because of much overlap, but I can't find anywhere that it actually explains why they are included. Certainly (I hope!) they aren't claiming that all sleep disorders are psychiatric disorders? Yet I know that some people insist that since they are in a manual with that name, that means that all sleep disorders are mental illnesses. I note that the ICD prefaces each sleep condition with "non-organic"; DSM doesn't.

I've looked for a good, reliable explanation. Can you find one?

Thanks, --Hordaland (talk) 05:16, 13 January 2017 (UTC)[reply]

The purpose of the DSM is to provide a clearly-defined technical language for professionals (especially psychiatric medical doctors). This enables consistent diagnosis and description.

The DSM, by itself, doesn't provide an explanation or causal link for the various conditions.

Nor does it preclude a causal link to some other condition; nor does it preclude comorbidity with other medical conditions.

So - to answer your question - the DSM contains a large chapter on sleep disorders because providing a consistent nomenclature and a formal technical language to describe such disorders is useful to the audience of professionals and researchers who normally use the DSM. The inclusion of the section on sleep disorders does not imply that every sleep disorder is a mental health issue. It simply provides a clear and consistent technical language, commonly used by mental health professionals, that can describe certain sleep disorders.

There is probably no better reference to cite than the DSM itself: in the introduction to the section on sleep/wake disorders, it says: "this chapter is designed to facilitate differential diagnosis of sleep-wake complaints and to clarify when referral to a sleep specialist is appropriate for further assessment and treatment planning." A sleep complaint certainly need not be a mental illness, even if a person seeks medical help for it!

Nimur (talk) 05:59, 13 January 2017 (UTC)[reply]

Thank you, @Nimur:. Interesting and very sensible. Do you consider all the sleep-wake conditions described in the DSM as "mental" disorders or illnesses? I don't have access to the DSM; I wonder if it specifically states why sleep is included and points out that the conditions described aren't (necessarily) psychological, though they may have psychological consequences for some people. I've read several dictionary definitions of the word "mental" -- no help there.

(I do have a sleep-wake disorder. It's disturbing to be told that it's a mental disorder.) --Hordaland (talk) 06:38, 13 January 2017 (UTC)[reply]

I think there is a false assumption here, that DSM is only supposed to cover "mental" or "psychological" disorders. The reality is that the main function of the DSM is to provide a consistent set of labels for all the conditions that psychiatrists may be called on to treat. Even though sleep disorders are not considered psychological disorders per se, they are often co-morbid with psychological disorders. In particular the majority of people with serious depression also suffer from sleep disorders. Looie496 (talk) 13:53, 13 January 2017 (UTC)[reply]

I think two or three points ought to be made. Most importantly - we don't and won't try to tell the OP what their condition is - that would be providing a diagnosis, and we just don't do that on Wikipedia's science reference desk. We don't know what your condition is; we aren't going to try to diagnose it; we're just here to help readers find good, high-quality scientific references.

The OP has also expressed concern that some might call a sleep problem a "mental disorder." Would it help if we called it a "wakalixes disorder"? The name of the condition has no impact on how severe the condition is, nor on whether the OP needs professional help to solve it. The more important word in this case is "disorder" - which specifically means that something is not right. You can have any kind of sleep condition, but if you have a sleep disorder, it means that the condition is causing some kind of trouble. A professional can help you to find a probable cause and a suitable fix - and depending on your specific case, the cause might be something totally unrelated to your mental state.

Finally: whether or not anybody is formally diagnosed with a mental health disorder: there is no good reason to stigmatize "mental" health. Mental health issues are commonplace and many professionals and other support services are available to help people become well. Scientific research, like this 2007 study by the CDC, shows that we have a great need to help educate the public "about how to support persons with mental illness and the need to reduce barriers for those seeking or receiving treatment for mental illness." So: whatever comes of your investigations into your own sleep condition, maybe you can step away with a slightly enlightened view of mental health!

Nimur (talk) 15:14, 13 January 2017 (UTC)[reply]

Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations. ... And by the same organ we become mad and delirious, and fears and terrors assail us, some by night, and some by day, and dreams and untimely wanderings, and cares that are not suitable, and ignorance of present circumstances, desuetude, and unskillfulness. All these things we endure from the brain, when it is not healthy...
Hippocrates, On the Sacred Disease^[1]

References

^ *Hippocrates (2006) [400 BCE], On the Sacred Disease, Translated by Francis Adams, Internet Classics Archive: The University of Adelaide Library, archived from the original on September 26, 2007

Sleep is pretty emphatically a "brain thing", so it seems fairly logical to me. I can see why you might not consider something like encephalitis a mental disorder, as it's usually from an exogenous cause, but sleep is a behavior that arises from the brain. And from a purely practical angle, sleep disorders have a high rate of comorbidity with things like depression, so it makes sense to integrate them into the DSM. (I have Asperger's syndrome, major depressive disorder, and sleep apnea! Isn't life fun sometimes?) --47.138.163.230 (talk) 07:22, 13 January 2017 (UTC)[reply]

I agree with these comments. Excessive sleep, or lack of sleep, is associated as a symptom of many mental/mind/brain disorders. The reliable sources refer to hypersomnia and hypersomnolence disorder, as a mind, or mental disorder, not just the DSM-5! Hordaland, just because you said "I do have a sleep-wake disorder. It's disturbing to be told that it's a mental disorder" in your earlier comments, seems to be your personal opinion, and you not wanting the reliable sources to be calling it a mental disorder.Charlotte135 (talk) 14:28, 13 January 2017 (UTC)[reply]

life ascertation of guns in terms of EFC?

hi. can anyone help me know how to aseratin the life ascertation of guns in terms of EFC? — Preceding unsigned comment added by Dexterkhan (talk • contribs) 10:39, 13 January 2017 (UTC) — Preceding unsigned [reply]

Moved to new section - comment added by Wymspen (talk • contribs)

Maybe this will be obvious to someone more familiar with guns but what do you mean by EFC? Effective full charge? Expected Family Contribution (although I don't get how this relates to your question)? Something else? Nil Einne (talk) 12:48, 13 January 2017 (UTC)[reply]

It is noted at the link Nil Eine provided that the actual decision to retire any specific gun barrel would be made on examination and measurement of actual wear rather than that predicted by the EFC count. Blooteuth (talk) 13:45, 13 January 2017 (UTC)[reply]

Stopping power

How does the stopping power of a bullet (at equal distance, like say 25 yards) correlate with its (1) diameter, (2) muzzle velocity, (3) muzzle energy, (4) momentum, (5) propellant charge, and (6) ballistic coefficient? Which of these parameters correlates most closely with stopping power? Also, how do the following cartridges rank in stopping power (highest to lowest or lowest to highest, your choice): 5.56X45 NATO, 223 Remington, 22 Long Rifle, 7.62X39 Soviet, 7.62X51 NATO, 308 Winchester, 7.65X21 Parabellum, 9X19 Parabellum, 38 Special, 357 Magnum, 44 Magnum, 45 ACP and 45 Colt? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 13:49, 13 January 2017 (UTC)[reply]

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know.. --Jayron 32 14:03, 13 January 2017 (UTC)[reply]

There's controversy on this point. Until the 1960s, the Hatcher Relative Stopping Power formula was considered to be definitive in estimating the stopping power of ammunition (your question refers to the "stopping power of a bullet", when properly you should have referred to the "stopping power of a cartridge", because the bullet has no stopping power without a charge of propellant behind it and a barrel around it to spin the bullet and contain the expanding gases of the propellant - cartridge cases usually also figure into this, and the history of caseless ammunition indicates that cartridge cases are necessary for the best performance of a given combination of bullet, propellant charge and barrel).

From the 1940s to the 1970s various writers in the firearms press and consultants to the Federal government began examining the Hatcher Relative Stopping Power formula critically. The December 28th, 2012 post to the blog "Firearms History, Technology & Development" describes the history and specifics of estimating relative stopping power since Hatcher's RSP formula. loupgarous (talk) 20:58, 13 January 2017 (UTC)[reply]

The article Stopping power cited by the OP explains how many other factors than the bullet alone affect stopping power. Blooteuth (talk) 21:42, 13 January 2017 (UTC)[reply]

But the OP didn't appear to have internalized that knowledge. Now the OP can read the materials I pointed out as well as our article Stopping power and answer the original question knowledgeably. loupgarous (talk) 21:48, 13 January 2017 (UTC)[reply]

I'd like to know what type of course the original question might be a homework question in. I know I can't think of one. --69.159.60.210 (talk) 00:08, 14 January 2017 (UTC)[reply]

Honey bee behavior and oatmeal?

I noticed something strange today when I went to toss some scraps onto the compost pile. There was a huge congregation of bees rolling about in a mound of quick oats (which I had mistakenly bought, thinking they were the old-fashioned style that I happen to like). I couldn't find any references to this sort of behaviour and would like to know if this has been observed before. Also, any theories as to why they do that sort of thing? I did take a video of them, but haven't yet figured out how to upload it. If and when I do I will post a link here. Thanks! Earl of Arundel (talk) 22:14, 13 January 2017 (UTC)[reply]

It is possible you saw a mass of drones around a queen when she was on a mating flight, or whilst she was trying to start up a new colony. See here[44] DrChrissy ^(talk) 23:25, 13 January 2017 (UTC)[reply]

Perhaps, but it almost seemed like they were eating the stuff. But also sort of wallowing around and such. Very peculiar. I'm going to check the pile periodically over the next few days to see if they keep at it. Earl of Arundel (talk) 00:01, 14 January 2017 (UTC)[reply]

To bee or not to bee, that is the question here. There are a lot of flying insects that look like bees, especially in the southern states. So would like to see the video or some stills first for identification. Problem is that even quick-oats (that have been steam treated) are mostly starch which is toxic to bees as far as I know. So would be surprised if they are indeed honey bees ... unless Monsanto have genetically created some sort of kamikaze breed. Use a still digital camera. Images from them are easier to upload and upload them to Wikimedia Commons. If you do not own a macro-lens see if you can borrow one as you will get a better photo. --Aspro (talk) 23:44, 13 January 2017 (UTC)[reply]

No, these were most certainly bees, now whether or not they were the honey-producing sort I can't say for sure. But yes, I will post a link to a photo or video here later (if I ever manage to get that bit worked out, that is!).Earl of Arundel (talk) 00:01, 14 January 2017 (UTC)[reply]

[Hippocrates-1] *Hippocrates (2006) [400 BCE], On the Sacred Disease, Translated by Francis Adams, Internet Classics Archive: The University of Adelaide Library, archived from the original on September 26, 2007

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