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April 16

DC-3 mountain ops

2 questions: (1) When performing a short-field, hot-and-high takeoff in a DC-3 at (or above) MTOW with a 20-knot tailwind, what is the optimal flap setting? (2) With the optimal flap setting for takeoff, given the following parameters: aircraft weight = MTOW + 1360 lbs., field elevation = 8400 ft., OAT = 2°C, wind = direct tailwind at 20 kts. -- what's the minimum runway length needed? (Question inspired by FSX mission "Crucial Extraction" from Aerosoft's "Flight Tales 2: Adrenaline" mission pack.) 2601:646:8E01:7E0B:88C9:21D2:79C0:44A3 (talk) 01:28, 16 April 2017 (UTC)[reply]

Flaps or no flaps? When you're at high density altitude, this is a very important question! A few weeks ago, me and my copilot spent our evening watching Density Altitude: The Nine Deadly Sins, an hour-long seminar presented by David Hunter, former Principal Scientist for Human Performance at the Office of Aerospace Medicine, Federal Aviation Administration.

"Wrong flap setting" is "deadly sin #8" in Dr. Hunter's talk.

"...There comes a density altitude above which the use of takeoff flaps actually increases ground roll."
"Don't use short field flap settings for high density altitude takeoffs (unless the field is truly short.)
- Short field flap settings offer a better angle, not rate of climb.
- At the typically long high-elevation airports flaps will be a hindrance to reaching V_Y more quickly.

This is a long, and technical, presentation. It's not going to tell you, in direct fashion, whether to use flaps or not to use flaps. It's going to tax your brain for everything it knows about mountain flying, so that you can make the best decision (simulated or real) about what will keep your aircraft safest. At high DA, you're often pushing the edges of the performance envelope of your aircraft. Every optimization along one axis is met by a degradation in some other performance metric. Do you want a slower rate of climb with better angle? Or do you want better margin against the stall with a poor climb gradient and marginal terrain clearance? Would you really take off with a 20kt tail-wind, or would you rather fight with the terrain in the opposite direction? What you don't know will kill you. (This is why - in the real world - we would delay or cancel the flight, even if the departure is "urgent").

To actually answer the quantitative parts: you need real and reliable performance charts for your aircraft - and you need to know how to use 'em! Have you got an E6B? The E6B computer costs less than the computer flight simulator software you're using, and it tells you how to calculate DA; then, you just have to read the rest directly off of your aircraft's performance charts. And yes - the former director of FAA's Aviation Human Factors division recommends hand-calculation using the E6B and the Take-Off Computer. Doing the math by hand, with an analog computer, is slower and less accurate than using a powerful digital electronic software computer; but the analog computer is shown scientifically to help you make a better decision.

Nimur (talk) 06:19, 16 April 2017 (UTC)[reply]

Thanks! In this case, I'm not concerned with terrain clearance -- I'm only concerned with reaching flying speed before running out of runway. And there's something I forgot to tell you about the runway -- it's 4,154 feet long, theoretically asphalt, and sloping on a 3.8% grade -- would the plane be able to take off under these conditions? Also, a related question (you can call it #3): At a gross weight about 1360 lbs. over MTOW (as specified above), is it even remotely possible for a DC-3 to maintain 8500 feet on 1 engine? 2601:646:8E01:7E0B:4457:AEC3:D9F:5111 (talk) 06:41, 16 April 2017 (UTC)[reply]

I'm going to preface this by saying "never fly above max gross..." because that's what the textbooks and the rules say. But if this is a question of physics: it is possible to fly above max gross; it's just significantly less safe. Above max gross weight, normal operations like taxiing, climbing, and even turns and banks, may cause structural failure of the aircraft. If you carefully follow certain rules and procedures, you can do it, safe-and-legal, but it is absolutely not normal. In aviation, when we hear the words "not normal", it is typically bad thing.

Not everyone agrees; Flying Magazine called max gross a "myth"; but what do they know? They're a fun read an an interesting trade-magazine - not a canonical source of correct information about aeronautics. Try asking a flight instructor if you can fly over max! Extra points if you say, "but I read all about it on the internet..."

Throw in the added complexity of multi-engine aircraft, and things get really weird: which engine failed? Was it the critical engine? So, again - these sorts of things come from your aircraft's performance charts - and your DC-3 simulator probably doesn't have really great and accurate charts... so let's default to the safer answer and say "no, the DC-3 can't be safely operated in that fashion." Has anyone ever done it? Well, those aircraft went through the wars...

Nimur (talk) 07:07, 16 April 2017 (UTC)[reply]

Yes, this is a question of physics -- is it possible, under these conditions (disregarding the structural considerations), to take off from the airstrip in question, and then to maintain altitude on one engine (the portside engine, to be exact -- in this mission it's the starboard engine that gets shot out right after takeoff)? And yes, I'm fully aware of the possibility of structural failure above MTOW -- in fact, Amelia Earhart had learned about it the hard way on her first (aborted) world flight attempt. Oh, and just to put this question about overloaded flying to rest: If you get rid of the extra 1360 lbs. and just try to take off at MTOW (the other conditions being as described above), would it be possible to take off within the specified distance and then maintain altitude on one engine? (Yes, I figured out how to prevent overloads in this mission -- once you board as many refugees as you think you can take (21, in this case), just increase power until the copilot shouts "We're leaving, close the f**king door!" (yes, he actually says that), and then the refugees will stop boarding.) 2601:646:8E01:7E0B:4457:AEC3:D9F:5111 (talk) 08:19, 16 April 2017 (UTC)[reply]

Let's build up to this problem: have you done a take-off roll calculation at sea level? And how about at 8400 feet? Next, how does the tail-wind factor in? Next, how does the emergency-checklist read for a single engine failure on takeoff? And how would you adjust for all the extra factors during the emergency?

I sincerely hope you aren't operating your simu-airplane without an appropriate simu-performance-chart! Those calculations are not optional - they are a very important part of flying your airplane! You must have and use those perf charts. I don't fly the DC-3; I don't have its limitations and numbers on hand, but I can say this: every single element in your scenario is urgent enough to warrant choosing not to take off in the first place. In combination, you're asking for (simu-)fatalities. This is not how pilots make decisions. We have seen things, and done things, that make us want those 5x- and 10x- margins.

For example, yesterday I was at sea level at KMRY in a single-engine aircraft. Sea level, and a perfect 12-knot headwind, on a seven thousand foot runway. To save a few bucks driving around on the ground, I opted for - and was cleared for - an intersection takeoff, 28L at K. As I rolled on the runway, I checked and verified three thousand feet of useful runway ahead of me. My aircraft can get off in, say, 600 feet in normal conditions; and with a 12 knot headwind... well, I can estimate 400 feet. So I had only about eight times more runway than I needed. As I rolled on to the runway, with four thousand useful feet already behind me, and eight times more than I needed ahead of me, the thought flickered across my mind: do I "actually actually" have enough runway ahead of me? And a moment of regret - why didn't I just taxi all the way to the end? Of course we took off with no trouble; but that's the kind of safety margin that makes a real pilot twinge. Your simu-scenario added mountains, terrain, hostile antiaircraft fire, overloading, sloping runway, short field, ... I mean, can you add a fogbank, questionable fuel, and an airsick pilot to the scenario for us just to bring the certainty of disaster closer to 100%?

So when you construct a scenario - simulated or otherwise - where you know you don't have the performance you require, you are so far from safe that no reasonable pilot would choose to take off. It would be better to stay on the ground and take your chances with the unfriendly groundlings who shot out that engine.

Nimur (talk) 16:20, 16 April 2017 (UTC)[reply]

I bet this is why FSX is not allowed for real pilot training -- because many of the missions (especially the harder ones) encourage the taking of risks which no pilot should ever take in real life (the "Jet City" mission being the most egregious example -- if you fly over (and under!) Seattle like that in real life, your "reward" would be a revoked pilot license and jail time for public endangerment -- and that's if you survive, which is unlikely!) But to get back to the question, the takeoff run for the DC-3 at sea level is listed in the learning center -- it's 1600 feet on a hard-surface runway with no wind. 2601:646:8E01:7E0B:B80C:1577:D989:3256 (talk) 00:32, 17 April 2017 (UTC)[reply]

Hm, that take-off roll (1600 feet?) sounds a little short, but I don't have a flight manual for DC-3 to verify... you really need a perf chart for the airplane (simulated or otherwise). But based on your questions, what you really need to do is go back to the Airplane Flying Handbook, with special emphasis on chapters:

Chapter 5: Takeoffs
Chapter 12: Transition to Multiengine Airplanes
Chapter 13: Transition to Tailwheel Airplanes
Chapter 17: Emergency Procedures

...and the PHAK, with special emphasis on:

Chapter 11: Performance

Nimur (talk) 23:40, 17 April 2017 (UTC)[reply]

BTW, just so you know, I actually made it off that field and stayed aloft on 1 engine, even with a full load of refugees (which put me 1300+ lbs. over MTOW, as well as made the plane dangerously tail-heavy) -- the key, as you said, was to keep the flaps all the way up. ;-) (And I didn't crash during that mission -- rather, my computer did.) 2601:646:8E01:7E0B:7D48:3AB5:AF2B:A040 (talk) 01:01, 18 April 2017 (UTC)[reply]

Ah, simulators... even when they're legal, it's hard to take them seriously...

Get back to studying your performance-charts, airman!

Nimur (talk) 14:36, 18 April 2017 (UTC)[reply]

Project_engineering

Just read [1]. Why is t that in some projects, project engineer reports to the project manager whilst in other cases, they are level in the structure, each reporting to their team manager who in turn report to the same project director. — Preceding unsigned comment added by 82.132.239.231 (talk) 15:05, 16 April 2017 (UTC)[reply]

Because that's how they want to do it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:42, 16 April 2017 (UTC)[reply]

Exactly. See: The Vertical Structure Vs. the Horizontal Structure in an Organization for more info. Aspro (talk) 18:20, 16 April 2017 (UTC)[reply]

In the organization I worked for, it was because project managers and people managers had different responsibilities: project managers were active engineers, or at least devoted to technical issues, but would not be responsible for things like hiring, performance evaluation, and promotion, which were the responsibility of the "people managers". In a complicated project, a project manager might be organizing some of the activities of several engineers (usually each engineer would have a designated fraction of full time equivalent (FTE = 40hrs/week) dedicated to a project). The project managers might aid the "people managers" in evaluating the people working on his/her projects, but the final say in the evaluation resided with the "people managers". Projects often spread across organizational areas, so some engineers would report to the same "people manager" as the project manager, and some would report to different "people managers". (I wish I could recall the exact title of the people managers; I think they were simply called "managers", or perhaps "engineering managers" to differentiate them from production and maintenance supervisors.)--Wikimedes (talk) 19:06, 16 April 2017 (UTC)[reply]

Doesn't PRINCE2 work on the vertical structure? 2A02:C7D:B95F:F700:9D03:FD57:30DC:BF4F (talk) 21:02, 16 April 2017 (UTC)[reply]

Sexual differentiation delay

According to Live Science, despite inheriting an Y chromosome already during conception, the human male sexual differentiation begins only after about 60 days when testosterone kicks in. Why there's such a delay between inheriting the chromosome and male development? Brandmeister^talk 17:47, 16 April 2017 (UTC)[reply]

Well it's not going to happen when it's a ball of undifferentiated cells. Sagittarian Milky Way (talk) 18:50, 16 April 2017 (UTC)[reply]

That, and also remember that just because you have certain genes in you genome doesn't mean they are expressed immediately. 86.28.195.109 (talk) 07:47, 17 April 2017 (UTC)[reply]

It's that way because it works. That's how evolution operates. Unless there is a definitely "better" way, the old way continues to be used. As to how this evolved, "ontogeny recapitulates phylogeny". -Arch dude (talk) 15:42, 17 April 2017 (UTC)[reply]

No, it doesn't. AndrewWTaylor (talk) 16:27, 17 April 2017 (UTC)[reply]

In a sense, sexual development begins even at a negative age. Looking up SRY, I see its expression begins prior to implantation of the embryo. [2] (I say this is a negative age because an IUD or other device to prevent its implantation is not an abortion, and because pregnancies are often timed from implantation) SRY is the most directly genetic part of a male sexual differentiation program, being on the Y chromosome and driving largely male appearance all by itself.

But your source is not wrong either: sexual development in the morphological sense starts at 60 days because neither a single cell nor a blastocyst has a place to hang a penis from (genital ridge). (Although, to be honest, it seems entirely possible that with just the right stain and a very good eye and a whole lot of human embryos you could spot some difference in morphology in the first few cells, some difference in the cytoskeleton that is simply not presently known... it's just probably not pole-shaped. ;) And of course you can look for Y chromosome and Barr body, but I think philosophically that isn't sexual differentiation because of unusual cases like Klinefelter's syndrome or a mutant SRY gene. That said cases like freemartinism show that sexual differentiation at the early stage is prone to change, much more than it is for transsexuals taking hormones later.) Wnt (talk) 12:23, 18 April 2017 (UTC)[reply]

Magnifying glasses/diopters

Cheap magnifiers with magnification 3.5x or above tend to have a short focal distance of ~12 cm or less which are not practical for many applications such as soldering. I've noticed that some purveyors of reading glasses refer to the diopter rating as magnification so I was wondering whether +7 diopter reading glasses might provide 3.5x magnification with a greater than usual focal distance (ideally 30-40 cm)? Alternatively it's possible to have glasses made online to a prescription - would they be able to do whatever magnification (5x?) with a long focal distance? --78.148.99.149 (talk) 18:57, 16 April 2017 (UTC)[reply]

Dioptre is defined as m⁻¹, which means that +7 dioptre lens has the focal distance of 1/7 m or about 14 cm. This does not seem very different from the mentioned 12 cm focal distance. Ruslik_Zero 19:38, 16 April 2017 (UTC)[reply]

File:Smallest loupe light .jpg

See Magnifying glass#Magnification. The Diopter value of a lens equals the reciprocal of its focal length measured in metres. Its magnification is MP₀ = (0.25 m)Φ + 1, where Φ is the optical power in dioptres, when held close to the eye, or MP = (0.25 m)Φ when close to the object. These assume the viewer sees comfortably at 0.25 m from the eye, but an older person may not manage such a near point.

Single lens magnifiers are limited to 5× or so before significant distortion occurs. A modification that allows 10x to 20x magnification is the Coddington magnifier. The Loupe spectacles with lighting illustrated are useful in dentistry and electronic inspection. Blooteuth (talk) 20:00, 16 April 2017 (UTC)[reply]

Thanks. I've found dentistry ones at 3.5x with 420 mm focal distance but I think they would be overall worse than my current 2.5x lens with ~200 mm focal distance since now the subject is further away, undoing some other magnification (although it is at least more comfortable to use). What about https://www.alie xpress.com/item/BIJIA-Portable-Zoom-Mini-Fishing-Glasses-Telescope-10X-Magnifying-Loupe-Green-Film-Binoculars-For-Outdoor-Concert/32661281596.html these]]? They're 10x but it doesn't say their focal length. It says the exit pupil distance is 0.8 m but I can't figure a way to derive the focal length from that. They're intended for watching football so I'm guessing they won't focus on something as close as 400 mm. Broken link to circumvent stupid spam filter. I'm not trying to sell magnifiers. 78.148.99.149 (talk) 21:17, 16 April 2017 (UTC)[reply]

water temperature of the Columbia River

Where can I find the water temperature of the Columbia River plotted over the course of a year? (Any recent year is fine)

Anywhere along the river is fine, but if possible I'm specifically interested in the section around Portland, Oregon. ECS LIVA Z (talk) 20:41, 16 April 2017 (UTC)[reply]

The USGS has this sort of data on their National Water Information System web site. Constructing a query is a bit complicated, but this URL should give you water-temperature data for 2016 for the Columbia at Dodson. They also have data for a number of other points in Oregon and Washington if you prefer. --76.71.6.254 (talk) 02:30, 17 April 2017 (UTC)[reply]

That's perfect. Thank you so much!! ECS LIVA Z (talk) 08:22, 17 April 2017 (UTC)[reply]

Natural selection and attractiveness - related?

Is the human mating process and what people find attractive related to natural selection? I.e. Can it be said that people who are found to be attractive by more of the population, are more likely to successfully find a mate and reproduce? 2A02:C7D:B95F:F700:9D03:FD57:30DC:BF4F (talk) 21:01, 16 April 2017 (UTC)[reply]

See sexual selection. Sometimes, the interaction between natural selection and sexual selection can have interesting consequences. I remember that there is a type of bird with very long tail feathers. The long feathers are believed to be maladaptive in terms of natural selection, but they are still favored because of sexual selection. 50.4.236.254 (talk) 21:10, 16 April 2017 (UTC)[reply]

Are you thinking about the bird of paradise? 2601:646:8E01:7E0B:B80C:1577:D989:3256 (talk) 00:34, 17 April 2017 (UTC)[reply]

Or peafowl? --Jayron 32 00:57, 17 April 2017 (UTC)[reply]

On the long run, sexual preference is itself subject to natural selection. So, sexual selection acts to prevent medium term drifts toward unfitness due to a temporary change in the natural environment. Count Iblis (talk) 00:35, 17 April 2017 (UTC)[reply]

Yes, sexual attractiveness translates into physical featness and as such successfull reproduction and mating. Large breasts and wide hips in women, for instance, contribute to successfull nursing and childbirth, respectively, while long legs were particularly important in prehistoric times, as it meant faster running speed. Brandmeister^talk 09:37, 17 April 2017 (UTC)[reply]

[Citation needed] on the assumption that finding large breasts more sexually attractive is a general human tendency. Physical_attractiveness#Breasts suggests it's a bit more complicated than that. Adrian J. Hunter^{(talk•contribs)} 01:38, 20 April 2017 (UTC)[reply]

So, in theory, shouldn't this mean that only the most attractive in society get partners? Yet in reality, almost all humans get a partner. What's happened here? 2A02:C7D:B8FC:9000:B8C7:87EC:A8:3648 (talk) 10:46, 17 April 2017 (UTC)[reply]

No, that's not entirely true. In general, the more attractive (whatever biology and evolution and whatnot have determined for that particular population is "attractive") tend to be more likely to find mates, but that doesn't mean that no lesser attractive individual ever finds a mate. Evolution works in trends and generalities over long periods of time, and is not deterministic on the individual level. --Jayron 32 11:03, 17 April 2017 (UTC)[reply]

I'd add that since attractive women and men are more likely to get a partner fast, this forces other mate-seeking people to adapt their preferences and tastes. As the result, when a man, for instance, can't find a tall blonde girl with large breasts for some time (as it often happens), he would eventually adapt and pick an average girl next door. Brandmeister^talk 11:15, 17 April 2017 (UTC)[reply]

Especially if he doesn't find blondes very attractive in the first place. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:21, 17 April 2017 (UTC)[reply]

Please note the paucity or complete absence of references above. For example, in querying the assertion "large breasts contribute to successful nursing", the only reputable sources I found stated the opposite. Breastfeeding and Human Lactation, University of Kansas, latest edition 2014: "Breast size does not affect the ability to breastfeed" (page 158); "the amount of adipose tissue [i.e. fat] does not affect either the breast storage capacity or the milk production" (page 82). A summary page from Milk Genomics, titled "Do larger breasts make more milk?": "Research into breast size and milk production shows that milk supply is not dependent on breast size." This is a reference desk: please provide references. Carbon Caryatid (talk) 22:06, 18 April 2017 (UTC)[reply]

I found a source here ... alas, this paper has so many problems with it that I can't really say it proves anything. To begin with, the lucky doctor who somehow gets every patient asked to allow him to twice measure the circumference of each breast is, well, a plastic surgeon doing breast procedures, and so this is not exactly a representative sample. More troubling is the fact that while it finds that breasts of women who had children have less fluctuating asymmetry, that doesn't necessarily prove that they find mates more easily. That's because pregnancy has no small effect on breasts, so they might fill out more evenly due to the physiology rather than selection! But most relevant for this discussion is that Table 3 shows no significant relationship between breast size and number of children. That said ... it's a small study, and the number of children in modern society may be a poor indicator of reproductive success under historical circumstances. And I'm too lazy to figure out what the signs of the non-significant relationships in those statistics mean to see if they point in the 'right direction' for the hypothesis. Wnt (talk) 11:06, 19 April 2017 (UTC)[reply]

To answer your second question see Matching hypothesis which says "people are more likely to form and succeed in a committed relationship with someone who is equally socially desirable". It's not that less "atractive" people don't get to breed - they just find partners of a similar level of "attractiveness" to themselves. And how many children they then have is not related to how attractive they are considered to be. Richerman (talk) 23:40, 19 April 2017 (UTC)[reply]

April 17

Fins

Plz tell me for a heat transfer equation of fins,we have different cases 1.convection from tip. 2.insulated tip 3.infinitely long. plz tell conditions to be met to assume fins to have insulated tip.

SD — Preceding unsigned comment added by Sameerdubey.sbp (talk • contribs) 04:54, 17 April 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 11:01, 17 April 2017 (UTC)[reply]

I'd like to see a penguin, seal, fish or dolphin with infinitely long fins. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:22, 17 April 2017 (UTC)[reply]

I believe the case with insulated tips implies heat leaves the fin through the two side faces of the fin, but not through the tip. Dolphin (t) 11:59, 17 April 2017 (UTC)[reply]

The article Heat sink has a section about fin efficiency that offers values for convection coefficient. Fin efficiency is defined as the actual heat transferred by the fin, divided by the heat transfer were the fin to have infinite thermal conductivity. However the key value to use in selecting a heat sink is its Thermal resistance defined as temperature rise in degrees Celsius per watt (°C/W). This is tabulated by heat sink manufacturers and the the temperature rise of the device over the ambient air can be calculated by multiplying it by the dissipated power in watts. Note that the thermal couplings of a semiconductor die to its case and of the case to the heatsink each represent thermal resistances in series with the heatsink, and in the latter case can be minimised by a thin layer of Thermal grease. SdrawkcaB99 (talk) 15:33, 17 April 2017 (UTC)[reply]

Governments

Why is it that governments don't have many scientists and engineers? They have nearly all policy specialists and supporting lawyers, economists and statisticians. 2A02:C7D:B8FC:9000:B8C7:87EC:A8:3648 (talk) 11:12, 17 April 2017 (UTC)[reply]

Who says they don't? ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:20, 17 April 2017 (UTC)[reply]

In the U.K. anyway. I checked their organograms. 2A02:C7D:B8FC:9000:B8C7:87EC:A8:3648 (talk) 12:30, 17 April 2017 (UTC)[reply]

Are you referring to an organization chart? Do such charts list every last employee? And do they include consulting firms? ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:33, 17 April 2017 (UTC)[reply]

Because scientists deal in facts, and politicians want to be able to ignore those. The aims of scientists and politicians are often almost diametrically opposed. Having said that there, are/have been scientifically trained heads of state (Angela Merkel, Margeret Thatcher, Elio Di Rupo just in Europe alone), and the current Dutch Interior minister (Ronald Plasterk) was a renowned molecular biologist. Fgf10 (talk) 14:43, 17 April 2017 (UTC)[reply]

There were just 2 scientists in the US Congress, as of 2015: [3]. This is somewhat understandable in the case of Republicans, who often run on an anti-science platform such as denying man-made climate change, supporting teaching "intelligent design" in schools, while opposing teaching evolution, etc. But, in the case of Democrats, more of an explanation is needed (although note that both current scientists are Democrats, as was the one who retired to bring the number down to 2). Running for office often requires the opposite of clear, plain statement of facts. For example, if you tell coal miners their jobs are gone and are never coming back, they won't vote for you. So, scientists tend to avoid politics, or, if they do run, they tend to lose if they try telling voters the truth. StuRat (talk) 14:57, 17 April 2017 (UTC)[reply]

In the U.S., both "pure" science and R&D are mostly contracted to private companies. This includes the companies that run the national labs like ORNL and LLNL, and the scientists and engineers that develop weapons systems. There are two major reasons. First: the political philosophy of "small government" gets translates into "fewer (direct) government employees." Silly. Second: government salaries are controlled via a cumbersome set of rules that make it very difficult to pay scientists and engineers competitively. Contracting to a company avoids this problem. -Arch dude (talk) 15:37, 17 April 2017 (UTC)[reply]

Government run by scientists and engineers is called (broadly) technocracy. Wikipedia's article on technocracy discusses some of the benefits and problems thereof. --Jayron 32 15:39, 17 April 2017 (UTC)[reply]

There are several examples of politicians and cabinet members with science and technology backgrounds. From the technology article linked by Jayron32 above, "...leaders of the Communist Party of China are mostly professional engineers". Margaret Thatcher earned a bachelor's and Angela Merkel a doctorate in physical chemistry, Steven Chu has a Nobel Prize in physics, and Jimmy Carter has a background in submarine nuclear engineering.--Wikimedes (talk) 21:42, 17 April 2017 (UTC)[reply]

not the place to discuss these matters--Jayron 32 17:31, 18 April 2017 (UTC)[reply]

The following discussion has been closed. Please do not modify it.

Humans have existed for more than 200,000 years, politics has existed in some form for all that time and even before (I've seen a documentary about politics in ape societies). So our brains are adapted to use politics as a method to function in society. But science is a recent invention. While today we may think that in the old days the church repressed the people to keep them away from science, this is not the correct way to think about this issue. Our brains are programmed to respect authorities, so the Church had the respect of the people and they would then side with the Church if that authority would be challenged. Now science is all about being skeptical, statements need to be rigorously proven, it should be possible for anyone to question anything, the answer can never be an argument from authority. This is the complete opposite of how our minds have evolved. While science has made more and more inroads into society in the last few centuries, we're still the same old people who think in an extremely anti-scientific way about most things in life. Count Iblis (talk) 21:27, 17 April 2017 (UTC)[reply]

in my experience, people who cry the loudest how we shouldn't trust our puny brains also tend to swear by wheatgrass juice and oil pulling and such things, and to think that Ferguson and Berkeley were the result of active measures by a foreign power, so... Asmrulz (talk) 16:43, 18 April 2017 (UTC)[reply]

Aside from the alcohol, what's the difference between wheatgrass juice and beer? And what foreign powers? The cops? The white supremacists? ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:09, 18 April 2017 (UTC)[reply]

Please hold these discussions outside of Wikipedia. This is not the purpose of the reference desks. --Jayron 32 17:31, 18 April 2017 (UTC)[reply]

Injected drugs coming out in the feces

Recently I was reading about an intravenous drug (Vincristine), and was surprised that the primary mode of elimination (~80%) is apparently via feces [4]. I assume that means that the drug is moving from the blood into the bowel as its main mode of elimination. How common is this? I had pretty much assumed that the elimination of injected/intravenous drugs was either in the urine (via the kidneys) or by being broken down chemically (e.g. in the liver). I can't recall having heard of anything that moves from blood to bowel in any significant degree. Are there natural substances produced in the body (i.e. not artificial drugs) that are also excreted by moving into the bowel? In a circumstance like this, does the contents of the bowel then affect the rate of elimination? Dragons flight (talk) 13:48, 17 April 2017 (UTC)[reply]

The breakdown of hemoglobin involves transport into (and sometimes back out of, if I'm reading Urobilinogen correctly) the intestines (see Hemoglobin#Degradation in vertebrate animals). DMacks (talk) 13:58, 17 April 2017 (UTC)[reply]

I found a paper about this: [5]. It credits biliary excretion, and suggests that loss of liver function might lead to higher levels in the patient. We could use more data on this -- I know that bile salts are excreted in ~~gall~~ (I mean bile) to the intestine and tend to take some hydrophobic crap with them. Indeed the gallstone classically forms from cholesterol being dumped via this route, and vincristine is, at a zero-order approximation, another big complicated molecule with a lot of rings like that. But I'd be lying if I said I understood the mechanism in any meaningful degree. Wnt (talk) 12:37, 18 April 2017 (UTC)[reply]

That is helpful. DMacks link also suggested transport via the bile duct. That makes more sense for large molecules than direct transport from the blood. I was unaware that the bile duct could be used for elimination. Dragons flight (talk) 15:01, 18 April 2017 (UTC)[reply]

As others have said, the two most significant means of elimination are urine and gut. Urobilinogen excreted in urine gives urine its yellow color, while urobilinogen in the gut is converted to stercobilin that gives feces its usual coloration. - Nunh-huh 15:09, 18 April 2017 (UTC)[reply]

First let me clarify something. When they say it is eliminated in the feces, they do not mean that it wasn't 'broken down' by the liver. They give a small amount of mildly radioactive drug, and see where the radioactivity comes out, but that doesn't mean it is unchanged and still active. You may be misleading yourself with that term 'broken down': in this context it doesn't mean the same as 'broken up'. Everything in the circulation through the liver, which has enzymes (cytochrome P450s) that alter blood-borne compounds, adding or removing side chains or otherwise modifying the chemical bonding. When this results in a change that renders the drug inactive, it is referred to as having 'broken down' the drug, even though the change is minor. This has the effect of either making the compound more water soluble, more likely to be excreted in the urine, or less water soluble, which targets them to the bile ducts and into the feces. What determines which way it goes depends on which specific P450 is doing the modifying, and that can vary depending on genetics, personal history (alcohol consumption turns some of them up, others down), and how much of the compound the liver is faced with. Agricolae (talk) 20:48, 18 April 2017 (UTC)[reply]

This is true, but at the same time, metabolism of drugs is often pretty minimal chemically speaking, and this seems to be the case with vincristine. [6] One carbon atom somehow goes AWOL out of that immense structure with the help of CYP3A5, and that is sufficient to "break down" the drug (to metabolite M1). The weird part is that this apparently matters a lot - that paper says that African-American children treated for leukemia were 42% more likely to die than Caucasians, due to ethnic differences in the rate of weak CYP3A5 alleles. That said ... the Caucasians were more likely to suffer nerve damage and pain from the drug. Chemotherapy is no picnic whatever happens. So this seems to be a case where personalized medicine to get the exact dose right could pay off. See also [7]; I think there were more along this line. Wnt (talk) 03:26, 19 April 2017 (UTC)[reply]

I guess I didn't make myself entirely clear, because your 'at the same time' is exactly what I was trying to describe. The cytochrome P450, CYP3A5 (and to a much lesser extent CYP3A4), carries out a minor chemical modification, which 'breaks down' the drug, and this is affected by (among other things) genetics (for which racial background is a handy proxy). As to 'one carbon somehow going AWOL', specifically, CYP3A5 (& CYP3A4) carries out oxidative cleavage of a carbon-nitrogen bond in one of vincristine's rings. The product has a distribution of electrons so unstable that another bond spontaneously breaks, releasing an O=C—O—H group.[8] The loss of two oxygens makes the molecule less polar - more lipophilic, and hence more likely to be excreted in the bile, and at the same time, less likely in the urine. Agricolae (talk) 15:20, 19 April 2017 (UTC)[reply]

Mixing oil and water

Is there any oil that would mix well with water, without making an emulsion?--Hofhof (talk) 19:32, 17 April 2017 (UTC)[reply]

By definition, an oil cannot mix with water. Someguy1221 (talk) 20:11, 17 April 2017 (UTC)[reply]

I would say that if something mixes with water well, it is not an oil. Ruslik_Zero 20:14, 17 April 2017 (UTC)[reply]

This may be of interest, however. Brandmeister^talk 20:36, 17 April 2017 (UTC)[reply]

That got my attention. Specifically, "To test his hunch, Pashley removed almost all the gas from a water-oil mixture by repeatedly freezing and thawing it while pumping off the gases as they evaporated out". I have spent many long hours removing dissolved gasses from superpure water, and have always used [A] a vacuum at the surface, and [B] mechanical agitation. Never tried freezing and thawing. What is the theory behind that? --Guy Macon (talk) 21:07, 17 April 2017 (UTC)[reply]

We have an article about Degasification, including freeze–pump–thaw. If a liquid crystallizes, it often leaves solutes (including gases) physically separate, so then you can pump off those now-gas-phase molecules. That method is pretty standard in some labs, as is (and sometimes "as a step before other methods") sparging with an inert and/or less-reactive gas.DMacks (talk) 21:20, 17 April 2017 (UTC)[reply]

Odd to think that oil is hard to dry out once you get it wet. Here is the article reference. This cites it and is readily available. There are some others I didn't run down - just search like Pashley emulsion "phase transfer". I was wondering if the method has applications comparable to phase transfer catalysts, or perhaps other applications in chemical synthesis... Wnt (talk) 03:38, 19 April 2017 (UTC)[reply]

We have an article about Water miscible oil paint. DMacks (talk) 20:45, 17 April 2017 (UTC)[reply]

Depends on what you mean by fat, and what you mean by water. If you use fats in the technical sense, it would include, for example, steroids. These have a low but non-zero solubility water, so they would dissolve rather than forming an emulsion, but only in very small amounts. As to water, solubility it depends on what else is in the water. Soluble substances can be added that would make the resulting solution more lipophilic, resulting in hydrophobic substances (such as oils) becoming more soluble. Detergents and some alcohols have this effect - these are molecules with a hydrophilic head and a hydrophobic tail. The tails surround and coat individual molecules of oil, with their water-loving heads pointing out and interacting with the water. This is what happens when you wash oil off your hands using soap, and is also why many liquid medicines include alcohol. However, it doesn't take very much oil to overwhelm the capacity of the solute. (You can also add compounds to water to make it more lipophobic, which would drive out even the small amount of fat, or add a 'stronger' lipid to attract the dissolved fats away from the water.) Agricolae (talk) 20:18, 18 April 2017 (UTC)[reply]

April 18

Stupid question: What flowers are these?

[9] Thank you. 69.22.242.15 (talk) 00:36, 18 April 2017 (UTC)[reply]

Looks like cherry blossom to me. DuncanHill (talk) 00:38, 18 April 2017 (UTC)[reply]

Pretty sure that is a cherry blossom. Boomer Vial^{Holla! We gonna ball!} 00:46, 18 April 2017 (UTC)[reply]

Definitely cherry - and probably one of the Japanese varieties to get that deep pink. The image isn't clear enough to identify the variety. The only other tree which has similar bright pink blossom is the crab-apple - but that would have leaves as well as blossom. Wymspen (talk) 10:16, 18 April 2017 (UTC)[reply]

Indeed. Malus floribunda has similar flowers, but the leaves precede the blossoms by several weeks (or at least the one in my front yard does). With Prunus trees (plums, peaches, apricots, cherries, aka the Drupes) the flowers precede the leaves in spring. It's clearly a Prunus of some sort, "cherry blossom" is a possibility, but its hard to tell from that picture. Could be a peach blossom too, which also has similar pink flowers, or any of a number of plums, etc. which could have pink flowers. We'd probably need pictures of leaves and/or fruit to make a better ID. --Jayron 32 17:37, 18 April 2017 (UTC)[reply]

Ostrich wing span

I saw a cute commercial the other day of a very determined ostrich flying. How big would an ostrich's wingspan need to be for it to actually fly? 198.72.29.37 (talk) 18:44, 18 April 2017 (UTC)[reply]

This article has a handy graph which shows the wingspan/weight ratio for various birds. A simple linear regression can be done to extrapolate that data to the weight of a typical ostrich to figure that out. --Jayron 32 19:29, 18 April 2017 (UTC)[reply]

Very bizarre[10]. Is it real? --AboutFace 22 (talk) 19:30, 18 April 2017 (UTC)[reply]

If you mean have people filmed mature ostriches flying, no it is not true. That clip is currently being shown here in the UK as an advert for an electronics firm. I suspect the advert was created using CGI. DrChrissy ^(talk) 21:24, 18 April 2017 (UTC)[reply]

Jayron, thanks for finding that graph. I spent quite a bit of time looking for something similar but could not. Can you, or anyone else, please explain what that symbol before the 2 of the y-axis label means? DrChrissy ^(talk) 21:00, 18 April 2017 (UTC)[reply]

^2 means squared, to the power of two. It is used when the superscript is not possible. Wymspen (talk) 21:53, 18 April 2017 (UTC)[reply]

Right before "2" there is a caret "^" a symbol for the power. a^2 means a to the power of two. Is it what you want? --AboutFace 22 (talk) 21:54, 18 April 2017 (UTC)[reply]

Ah - that makes sense. Thanks very much. Using very rough figures then, the graph indicates the wingspan of a flying human is approximately 7 metres. Male ostriches can weigh almost as much as two humans, so if the linear regression can be extrapolated this far, flying ostriches would have a wingspan of approximately 14 m! I suggest we don't encourage them! DrChrissy ^(talk) 22:39, 18 April 2017 (UTC)[reply]

Just as a follow up, our article on the extinct Pelagornis sandersi states it is the largest flying bird discovered with a wingspan estimated to be between 6.1 and 7.4 m (20 and 24 ft). DrChrissy ^(talk) 22:56, 18 April 2017 (UTC)[reply]

As far as current birds, the great albatross is no slouch, with a wingspan up to 3.5 m. Also note that any attempt to figure out what wingspan an animal would need, based on it's weight, must also figure in the weight of those huge wings. StuRat (talk) 23:03, 18 April 2017 (UTC)[reply]

I think the additional weight of the wings would be a secondary consideration. The muscles required to fly would be massive and the keel bone (to which the flight muscles attach) would also need to be massive. DrChrissy ^(talk) 23:08, 18 April 2017 (UTC)[reply]

Yes, and then you'd need a bigger heart and lungs to provide oxygen for all that additional muscle, a stronger spine to support it all, etc. StuRat (talk) 02:15, 19 April 2017 (UTC)[reply]

Bird spines aren't particularly strong, see bird skeleton. To give a better lever arm, the flight muscles are anchored to the keel bone (an extended sternum) rather than to the spine. The pelvis can also be a large muscle attachment, depending on the species. It's generally the flightless birds that have the largest and strongest pelvis, and for some also the spine. The ostrich here is actually more solidly built (except for keel and wings) than a hypothetical flying ostrich. Andy Dingley (talk) 15:15, 19 April 2017 (UTC)[reply]

Birds (and all living things. Well, all things) are constrained by what is called the square-cube law. As wings grow in size, they grow in both weight and area; weight would be proportional to volume, which grows in three dimensions, while lifting force of a wing is related to surface area, which grows in two dimensions. That is, if you double the length of a wing (while keeping all other dimensions proportional), you increase its lifting force by a factor of 4 and its mass by a factor of 8. If you triple the length of a wing, you increase its lifting force by a factor of 9 and its mass by a factor of 27. This kind of scaling is why super large airplanes become hard to build; as the wings increase in size, they increase in mass faster than they increase in lifting power. The same would apply to the weight of bird wings. Larger birds have a greater proportion of their mass devoted to being wings. Compare humming bird to condor for example. --Jayron 32 14:52, 19 April 2017 (UTC)[reply]

A difference is that airplanes are hollow, and the wall thickness isn't necessarily proportional to size. That is, an airplane 10x as long doesn't need to have a fuselage 10x as thick. Some birds, do, however, have hollow bones. As for airplane size restrictions, economics seems to limit the size of commercial planes. There aren't many routes that can support 1000 passenger planes, especially if they need to pay to lengthen the runways, modify the terminals, etc. StuRat (talk) 15:42, 19 April 2017 (UTC)[reply]

The article I already linked deals, in a small part, with square-cube law as it relates to airplane design. It's nice that you have ideas, but references beat ideas every day. ALso: "The effect of aircraft growth on empty weight [is based on] the square cube law... The actual wing structural weight fraction will increase with the size of the aircraft". I assume you're looking at a source for your statement? Since you found a source for your statement before you thought to make it, perhaps you can share it? --Jayron 32 16:14, 19 April 2017 (UTC)[reply]

That article states: "The square-cube law is based on many simplifying assumptions and has been defeated by the ingenuity of designers. Aircraft will not be scaled up according to geometric similarity...". Geometric similarity is making a plane that's 10x as long also have 10x the wall thickness. StuRat (talk) 02:12, 20 April 2017 (UTC)[reply]

This reference (Ellington, C. P. "Limitations on animal flight performance." Journal of Experimental Biology 160, no. 1 (1991): 71-91.) states "...maximum size for flapping flight is often taken as 12-16 kg" DrChrissy ^(talk) 17:40, 19 April 2017 (UTC)[reply]
That makes sense for birds, I think the largest flying birds are the condors which tops out at 14 kilograms, and bustards which tops out at 18 kg, so in that range. List_of_largest_birds#Table_of_heaviest_living_birds are all flightless until we get to the Kori bustard. (the domestic turkey can hypothetically fly, and their wild cousins do, but farm raised turkeys are bred in such a way as to make flight impossible. [11] --Jayron 32 18:07, 19 April 2017 (UTC)[reply]
I'm not sure I can agree with all of this. I once worked on a research project on the behaviour of farmed turkeys. As youngsters, they can sort of fly. They like to do vertical takeoffs to land on elevated objects - including the researcher's head. As sub-adults (16-19 weeks of age), I have never seen one fly. I'm not sue what you mean they are bred in ways which make flight impossible. Here in the UK, turkeys are reared in vast sheds which are sometimes converted airport hangars. I don't see how these would prevent flight. It is also relevant that the slaughter weight of males is 18-20 kg, so if they are able to fly, they would possibly be the heaviest flying bird. They also continue to put on weight after this time if they are not slaughtered which would put them way beyond the limit suggested above. Sorry this is all OR. DrChrissy ^(talk) 18:37, 19 April 2017 (UTC)[reply]
"As sub-adults (16-19 weeks of age), I have never seen one fly." You just answered your own question with your own experience. I don't know why you think adult domestic turkeys are capable of flight. You said you've never seen one. I don't understand why you would say I was wrong, and then say you don't agree with me when you then immediately do. The Wikipedia article states the same thing you do. But, if you need more sources regarding the difference between domestic and wild turkeys: [12] It notes how wild turkeys can fly, but that domesticated turkeys do not because, and I quote, "Farmers prize turkeys that grow large breast and thigh muscles, because those are the most valuable parts in the poultry market. Over time, farmers have bred turkeys to have larger and larger breasts. A turkey breast gets stronger as it gets larger, but the animal’s power-to-mass ratio diminishes, so it can’t flap quickly enough to support sustained flight." Not only a statement which references breeding as why domestic turkeys do not fly as adults, but ALSO a reference to the square cube law as to WHY they cannot! --Jayron 32 18:49, 19 April 2017 (UTC)[reply]
Apologies Jayron. I should have read your posting more carefully. You said "the domestic turkey can hypothetically fly" (my emphasis) - I missed the rather vital word "hypothetically". As for the way which turkeys are bred preventing them from flying, I jumped to the incorrect conclusion you were referring to environmental conditions. I agree totally with the reason for their not being able to fly is intense artificial selection to increase the size of breast muscles. Apologies for the confusion. DrChrissy ^(talk) 19:04, 19 April 2017 (UTC)[reply]

Wheatgrass

Aside from the alcohol, what would be the difference(s) between wheatgrass juice and beer or malt liquor? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:08, 18 April 2017 (UTC)[reply]

From the article you already linked, the third sentence "Wheatgrass differs from wheat malt in that it is served freeze-dried or fresh, while wheat malt is convectively dried. Wheatgrass is allowed to grow longer than malt." Malt is the stuff that serves as feedstock for brewing. --Jayron 32 19:25, 18 April 2017 (UTC)[reply]

Let me be more specific: How does it taste compared with the other items? ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:56, 18 April 2017 (UTC)[reply]

You... seek a plain-language description of the taste of wheatgrass, written to a standard that would qualify as an encyclopedic and scientific reference? Well, why don't we start at the main article on qualia and see where we end up?

Almost everything you will find on the web for wheatgrass is going to be a commercial vendor trying to sell it at you. There just aren't very many philosophers who write about the subjective character of experience and make specific reference to wheatgrass.

Here's a really nice organic farm that will sell wheatgrass to you, via mail-order: the Dynamic Greens Wheatgrass Juice from the Stem Family Farm. What does wheatgrass taste like? "Neutral and unfamiliar but not unpleasant," ... and so on.

...For a few bucks, you can just buy a cup of wheatgrass juice at almost any Jamba Juice in the United States... here's the store locator... the marketing-ese text calls the juice "flavorful," so that's about all you're going to get. Even if you think it's silly, you can try it anyway and laugh it off as a novelty experience; you might even enjoy it.

And if you don't want to drink it because it is green, here's the research paper you ought to read: Baeyens, Flavor-Flavor and Color-Flavor Conditioning in Humans (1990), on the Pavlovian cross-stimulus conditioning of rat- and human- response, relating color, flavor, and ... well, nuclear radiation, as it turns out. (I found these articles while reading Plato's encyclopedia article on Associationism during my search for encyclopedic articles about wheatgrass juice).

Nimur (talk) 21:29, 18 April 2017 (UTC)[reply]

I just wondered if it tasted like non-alcoholic beer or not. But thanks for the tip. I'll see if I can find someplace where I can get a small sample. And if I do, I'll report back here. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:42, 18 April 2017 (UTC)[reply]

April 19

ISO classification of materials

I some times see non-ferrous metals being referred to as "ISO N"[13]. There's a corresponding one letter ISO code for most common materials. Which specific ISO standard is this defined in? ECS LIVA Z (talk) 01:29, 19 April 2017 (UTC)[reply]

Here are the ISO codes for metallurgy - https://www.iso.org/ics/77/x/ - they are entirely numeric. I can locate no use of the letters you refer to except by the company website you linked to. It may be an older system that they have retained, even though no longer official. Wymspen (talk) 12:02, 19 April 2017 (UTC)[reply]

Thats a very special ISO exclusively dedicated to categorize hard cutting materials! Its called ISO 513 and it has infact a Group "N". Sandvik is a producer of the Inserts for metal cutting which are usually made from Cemented carbide material as categorized in ISO 513. Unfortunately Sandvik got a little "sloppy" with their ISO description and its a shame they dont mention ISO 513 anywhere on that page or they fear they would have to pay the very hefty licences all ISO authorities ask for any printed ISO-page or part. I could only find some foreign pictures of the list that usually is used for study or reminder by professionals. Just check out what pictures google offers when you search "ISO 513" and you will find your "N". --Kharon (talk) 21:32, 19 April 2017 (UTC)[reply]

Moving across the monkey bars

Is there an easy way to move across the monkey bars? For some reason, I have never acquired the ability to move across the monkey bars. I can just hang on one bar with both hands until my hands burn, and I fall down. If I release one hand, then I will fall down quicker. How do I train my arm muscles to become stronger? 50.4.236.254 (talk) 01:49, 19 April 2017 (UTC)[reply]

Search "train for monkey bars" on Google. You will find sites like this, this, this, and this. In short, you're just going to have to spend more time on monkey bars or else do lots of pull-ups. Push-ups train an opposing group of muscles that should be balanced with the pull-up group but do not directly help with monkey bars. As this illustrates, your natural build will also affect things. Ian.thomson (talk) 02:11, 19 April 2017 (UTC)[reply]

There is no article written for children? Does that mean or imply that children have an intuitive sense of moving across monkey bars and then losing this ability due to forfeiting recess time during middle school and high school years? 50.4.236.254 (talk) 02:21, 19 April 2017 (UTC)[reply]

Outside of very early childhood, your weight generally increases faster with age than your strength. So a 10 year old will typically have an easier time lifting his own weight than an out-of-shape adult. Someguy1221 (talk) 02:51, 19 April 2017 (UTC)[reply]

Um, but I never acquired the ability to move across the monkey bars. As an 8-year-old, I couldn't do it. As a 10-year-old, I couldn't do it. Even as an adult, I can't do it. I don't think I am out-of-shape, because my legs seem to be more powerful than my arms. I just can't lift my own weight. 50.4.236.254 (talk) 03:15, 19 April 2017 (UTC)[reply]

Strength in one muscle group bears no relationship to other muscle groups, especially when it's legs and arms. Ian.thomson (talk) 03:27, 19 April 2017 (UTC)[reply]

The problem may be technique more than muscles, specifically, starting from a static position. There's typically a ladder on one side, and you can climb it on the inside, turn around so your back is to the ladder, then grab the first of the monkey bars with one hand only, and your inertia should carry you forward enough to grab the second bar with your other hand. When you reach that bar, you let go of the first, and your inertia carries you on to the next bar, etc. With practice it gets easier. StuRat (talk) 02:13, 19 April 2017 (UTC)[reply]

A scaling law is also involved. Your strength is (vaguely) proportional to the area of muscles, i.e. the square of your linear size, but your weight is proportional to volume, thus the cube of linear size. So "a child" of "equal fitness" as they grow larger starts out able to pull themselves up and around monkey bars, but becomes less so as they grow - not because they are lazier or weaker, but simply from this scaling. To pull up on monkey bars at adult sizes, you will need to train and build a little more physical strength than is typical - although not an unachievable amount. Andy Dingley (talk) 12:12, 19 April 2017 (UTC)[reply]

Why the mixing of DNA is prohibited in human by law?

Why the mixing of DNA is prohibited in human by law? — Preceding unsigned comment added by 110.34.22.169 (talk) 04:12, 19 April 2017 (UTC)[reply]

Eh? I have no idea what you are talking about. Can you talk about the context? 50.4.236.254 (talk) 04:23, 19 April 2017 (UTC)[reply]

It isn't. How do you think babies are made? MarnetteD|Talk 04:26, 19 April 2017 (UTC)[reply]

Something involving a bird, a bee, a seed, a stork? EdChem (talk) 04:29, 19 April 2017 (UTC)[reply]

I've seen a number of Sci Fi films covering those :-) MarnetteD|Talk 04:33, 19 April 2017 (UTC)[reply]

The Asilomar Conference and this link [14] from the article should at least give some background information on your question.--Wikimedes (talk) 04:50, 19 April 2017 (UTC)[reply]

I would guess they are asking about genetic engineering of humans to include animal DNA. I believe the scientific consensus is that this is a bad idea, but I don't know if it's actually illegal in most places. StuRat (talk) 04:53, 19 April 2017 (UTC)[reply]

Another possibility - at least some jurisdictions have made it illegal to carry out human germline genetic manipulation, though many of these permit non-germline gene therapy. Agricolae (talk) 15:32, 19 April 2017 (UTC)[reply]

I agree that the OP is asking about genetic engineering of humans with non-human DNA. I'm not sure whether it's specifcally prohibited by law anywhere, though any kind of DNA manipulation of an embryo is prohibited some places. I'm sure I've read about ethical views on this, but I can't think of where. The only mention I can find in Wikipedia is in Genome editing#Human enhancement, which says According to a September 2016 report by the Nuffield Council on Bioethics in the future it may be possible to enhance people with genes from other organisms or wholly synthetic genes to for example improve night vision and sense of smell.[59][60] You might check references 59 and 60 and see where that leads you.

Note that there is a distinction between inserting non-human genes into a human embryo to prevent disease and inserting them into an adult to cure disease. Loraof (talk) 15:39, 19 April 2017 (UTC)[reply]

ManBearPig, Do no harm, Frankenfood. μηδείς (talk) 19:16, 19 April 2017 (UTC)[reply]

Could it be a trolling reference to miscegenation? There are (or were) anti-miscegenation laws. Bus stop (talk) 19:30, 19 April 2017 (UTC)[reply]
- Maybe, though he asked why it's prohibited, as opposed to why isn't it prohibited. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:04, 19 April 2017 (UTC)[reply]

Winged ants

A few of these

have been poking around the last few days. The smaller tick marks are millimeters, so the small ant is about 3.5mm long and the large one about 7mm, though slightly curled up.

I'm generally curious about them, and any information would be welcome, but I have a few specific questions: 1) Are they ants or termites? 2) What species are they? (or whatever clade you can narrow it down to.) 3) Are they a male (smaller) and female (larger, queen?) of the same species?--Wikimedes (talk) 04:38, 19 April 2017 (UTC)[reply]

According to Ant, the male (drone) and the breeding female (queen) age generally both winged, while the non-breeding females (workers) are usually not. These may all be drone ants of different species. --Jayron 32 12:16, 19 April 2017 (UTC)[reply]

These are definitely ants, not termites. This is the time of year in which winged males (generally smaller than queens, but often a bit larger than the non-winged and infertile female workers) and winged females/potential queens will emerge from their colonies and engage in their nuptial flight; they fly quite remarkably high in the air, in large numbers so as to overwhelm avian and insect predators (if these are in or near your home, keep an eye out for woodpeckers, jays and such as they really go for this annual no-hassle feast) and then mate at the apex of their ascent. They then return to the ground where the males die and the females lose their wings and begin their own colonies (or in particularly eusocial species, new satellite annexes of megacolonies). Given the morphology of these particular specimens, the location, and the timing, I'd say you are looking at some variety of Tapinoma, very possibly Tapinoma sessile; if they give off an offensive little odor if you disturb them and find any source of sugar left out instantly, you have a ballpark ID. If not, this source may be of further use to you. If not a species of Tapinoma, Formica would be next best bet. With some extra photos, I may be able to make a more definitive identification. Snow ^{let's rap} 20:07, 19 April 2017 (UTC)[reply]

Feynman Lectures. Lecture 52.Ch.52-5 Reflection symmetry 2. archive

...
Now if the law of reflection symmetry is right in physics, then it must be true that the equations must be so designed that if we change the sign of each axial vector and each cross-product of vectors, which would be what corresponds to reflection, nothing will happen. For instance, when we write a formula which says that the angular momentum is L=r×p, that equation is all right, because if we change to a left-hand coordinate system, we change the sign of L, but p and r do not change; the cross-product sign is changed, since we must change from a right-hand rule to a left-hand rule.

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

According to the Lecture 20 we have the coordinates of a vector product and the rule to build it (the right-screw rule). Suppose we have $\mathbf {r}$ and $\mathbf {p}$ coordinates png. We draw the vector product by the coordinates. Then if we change the coordinate system to left-handed and again draw the vector product it will be built by left-screw rule png. How is it possible? So what should we use right-screw rule or coordinates? .

Username160611000000 (talk) 07:23, 19 April 2017 (UTC)[reply]

I think Feynman is saying that L = rxp is only true in a right-handed co-ordinate system. If you switch to a left-handed co-ordinate system (by inverting the z-axis, for example) then the rule becomes L = - rxp i.e. a right-hand rule in a right-handed co-ordinate system becomes a left-hand rule in a left-handed co-ordinate system - see right-hand rule. Another way of expressing this is to says that angular momentum is a pseudovector. Gandalf61 (talk) 08:53, 19 April 2017 (UTC)[reply]

@Gandalf61: Feynman mentioned that in lecture 20 :

...

${\begin{aligned}&\tau _{xy}~&&=x&&F_{y}&&-y&&F_{x}&&,\\[.5ex]&\tau _{yz}~&&=y&&F_{z}&&-z&&F_{y}&&,\\[.5ex]&\tau _{zx}~&&=z&&F_{x}&&-x&&F_{z}&&.\end{aligned}}$

We digress at this point to note that in such cases as this one may get the wrong sign for some quantity if the coordinates are not handled in the right way. Why not write $\tau _{yz}=zF_{y}-yF_{z}$ ? The problem arises from the fact that a coordinate system may be either “right-handed” or “left-handed.” Having chosen (arbitrarily) a sign for, say $\tau _{xy}$ , then the correct expressions for the other two quantities may always be found by interchanging the letters $xyz$

in either order xyz or xzy

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

So it's no matter what the coordinate system we have , sign of z-coordinate is chosen arbitrary, and for right-hand system and left-hand system the formulas for x- and y- coordinates become the same.

Username160611000000 (talk) 13:56, 19 April 2017 (UTC)[reply]

And second question: Where should we stop the reflection operation ? Here (just going to left-hand system) or here (redrawing in usual form)? If first, then I don't understand the figure 52–3, because in left-hand system vectors ω must be opposite. If second, then I don't understand why should the vector product $\mathbf {r\times p}$ become $-\mathbf {(r\times p)}$ Username160611000000 (talk) 14:32, 19 April 2017 (UTC)[reply]

Would effervescent vitamin c tablets still be usable after 20 years?

In my kitchen cupboard I found an unopened fully shrink wrapped box of "Redoxon Effervescent Vitamin C" with an expiratory date of November 1996. I am NOT going to use them but I just wondered out of curiosity whether or not they would still actually contain Vitamin C that is usable to the body. Or would the Vitamin C have broken down after 20 years? The ingredients are listed as "Vitamin C (ascorbic acid BP), Sodium Tartrate, Sucrose, Flavourings, Colours Apo-Carotenal, Riboflavin, Artificial Sweetener Sodium Saccharin, Sodium Chloride. Thanks for your time

This is more of a materials science question than a pharmacological one. Vitamin C has a very long storage life in dry conditions - decades. In these typical tablets, the usual "failure mechanism" is by the effervescent agent (the sodium tartrate) absorbing moisture from the air. This gives the typical soft, spongy and slightly expanded appearance of most old Vit C tablets.

The question is how well hermetically sealed they were. "Box" and "shrink wrappped" just aren't enough - those materials are permeable to moisture over a timescale of years. If your kitchen cupboards are at all damp, I'd expect the box itself to start looking damp-affected by now. Usually though, effervescent Vit C is packed in a plastic tube, either polyethylene or polypropylene, and with a dessicant pellet inside the lid. Even then though, LDPE is water permeable - certainly on this decades timescale. A serious problem if you're laying telephone cables, and why polyethylene cables also have moisture barriers of aluminium foil and an internal grease packing or dry air pressurisation. If these tablets were packed for long-term storage, they'd instead be in aluminium tubes with a screwed cap. Those can easily be rated for 50+ years. Andy Dingley (talk) 09:10, 19 April 2017 (UTC)[reply]

Rather than just guess, it is easy to purchase some 2,6-Dichloroindophenol Sodium Salt and then assay it for oneself. Youtube even has some demos to show how you can do it in one's own kitchen. Vit C is also heat liable. So it depends on the storage temperatures also. Aspro (talk) 11:21, 19 April 2017 (UTC)[reply]

The predictability of humans

I remember that there was an online game, in which the artificially intelligent algorithm tried to compete with the human player. As time moved forward, the algorithm learned the human patterns and began winning games, because the human was becoming more and more predictable. However, the algorithm also displayed its own "thinking process" and "prediction" of the human's next move, so the human, with that knowledge, could make a choice in contrast to the algorithm's prediction. At that point, isn't the algorithm pushing the human to become truly random or unpredictable? Biologically, do humans manifest a greater degree of randomness than other animals to the extent that it appears as though humans are harder to predict? So, in order to defeat other humans, a human must be able to observe the biases that govern other humans while trying to hide his own biases by misleading other humans? 50.4.236.254 (talk) 13:59, 19 April 2017 (UTC)[reply]

I'm not really sure where you're going with your question, but the concept in your last question about "observe the biases that govern other humans while trying to hide his own biases by misleading other humans" is a level of cognition known as metacognition, which literally means "reflexive thinking" and refers to the ability of a person to understand their own thought processes and to control them. There is also what is known as theory of mind which is a related skill, and refers to the ability of a person to understand another person's thought processes; that other people have minds like yours, which are also distinct from yours, and further how to understand how their minds are likely working. --Jayron 32 14:13, 19 April 2017 (UTC)[reply]

In a non-cooperative game in which opponents can change their strategy - whether the players are human or machine - the strategies can continue to evolve each time you play the game, until all players finally reach the Nash equilibrium strategy. That is the point in the game at which no further strategy-change, by any player, will yield a statistical improvement in the chance of winning for any participant.

In a simple, constructed game that is designed to study game theory, we can use mathematical formalism to describe the equilibrium strategy "exactly." This also works for real games like blackjack.

In sophisticated games, where the decision space is quite enormous, it can be hard to formalize the strategy, and it can be mathematically intractable to solve for the provably-optimal strategy; but the concept still applies: in broad brush-strokes, a strategy can account for an opponent who may make "unpredictable" choices. There does exist a "best" strategy: even if the "best" strategy sometimes loses (e.g. when it guesses wrong about its opponent's plan), it is statistically more likely to win.

Intelligent data-driven humans and computers can use methods of statistics to model the opponent's behaviors, in the pursuit of playing with an optimal strategy.

Nimur (talk) 15:19, 19 April 2017 (UTC)[reply]

The OP asked whether the given scenario is pushing the human to behave randomly. A random strategy is called a mixed strategy. Loraof (talk) 15:59, 19 April 2017 (UTC)[reply]

It's not all that difficult to make people make precisely those "random choices" that you want them to make. Count Iblis (talk) 20:19, 19 April 2017 (UTC)[reply]

Which observation raises the even deeper epistemological inquiry of whether a human being (or any entity based on physical laws) is capable of doing anything that can be accurately described as truly "random"; hard determinism suggests this is a tautological impossibility. Snow ^{let's rap} 21:19, 19 April 2017 (UTC)[reply]

A buddhist carries that enquiry to the extreme of all-encompassing determinism known as Pratītyasamutpāda or interdependent origination: all things arise and exist due to certain causes (or conditions), and lose their existence once these causes (or conditions) are removed (see Idappaccayatā). However the enquirer must be prepared to discover himself or herself is no more than such an illusory thing, constantly re-imagining themself in a cycle of samsara. A physicist however, typically insists that physical phenomena such as the nuclear decay of atoms, can drive decisions that are truly random. Schrödinger speculated about the confusion such unpredictability might cause between one or more cat(s). Blooteuth (talk) 23:03, 19 April 2017 (UTC)[reply]

No offense, Blooteuth, but I wasn't really talking about mysticism, but rather the variety of metaphysics informed by hard science and natural and empirical (rather than religious) philosophy. I'm not saying these aren't interesting topics in their own way, but they are not really the same subject I was bringing the OP's attention, and are related only in the most tangential manner. As to the uncertainty principle, it also really has little to do with the question of determinism as it relates to human behaviour. For starters, uncertainty, as the term applies to complementary variables, is not the same thing as the abstract concept of "randomness". One is a product of mathematical and physical systems with a precise (if complex) function, while the other, as you use it, is more of a vague mental construction. And even if we were to theorize a truly "random" effect at the subatomic level, there would be no clear manner by which this effect would propagate "up" to play a consequential role in the biomolecular mechanisms which give rise to human behaviour--not withstanding the psuedoscientific wonkery of quantum mysticism nonsense. If it were as simple as you are suggesting, the very profound debate about determinism would have been over a long time ago. But you're actually comparing apples and oranges (and meaning no offense, but also describing both the apples and the oranges incorrectly). Snow ^{let's rap} 02:47, 20 April 2017 (UTC)[reply]

The question is asked "isn't the algorithm pushing the human to become truly random or unpredictable?" No. The algorithm is simply pushing the human to do things that the human has not done before. Randomness would serve no purpose. Of course the new things that the human is doing would have to be things that are acceptable to the human or which would lead to outcomes, several steps removed, that are acceptable to the human. Bus stop (talk) 22:34, 19 April 2017 (UTC)[reply]

A game in which the human's opponent reveals its "thinking process" and "prediction" is an entirely different game from one in which it is not displayed. The human will be evolving a new strategy to deal with the new rules, not becoming random. - Nunh-huh 02:21, 20 April 2017 (UTC)[reply]

Distinguishing phytoplankton from zoo plankton

Is there any easy way to distinguish phytoplankton from zoo plankton without using a microscope?? Georgia guy (talk) 15:56, 19 April 2017 (UTC)[reply]

How good is your eyesight? Assuming you mean unicellular life, then no, there isn't. If you mean plankton under the more formal definition, which is just "aquatic life that cannot navigate on its own", then yes, some plankton are clearly visible without a microscope. You'd need a large microscope to even fit a Portuguese man o' war on it; you can tell readily it is zooplankton, whereas seaweed is sometimes classified as a phytoplankton; it too is quite identifiable to the naked eye. --Jayron 32 16:04, 19 April 2017 (UTC)[reply]

1.0x magnification lens - what is the purpose?

[This head-mounted magnifie]r comes with a 1.0x lens. What could possibly be the purpose of a 1.0x magnification lens? Isn't that an oxymoron? --78.148.99.149 (talk) 18:24, 19 April 2017 (UTC)[reply]

In this one case, so you can use the head torch without any magnification. --Jayron 32 18:36, 19 April 2017 (UTC)[reply]

That make no sense because the headtorch doesn't need a lens in place to function? --78.148.99.149 (talk) 22:59, 19 April 2017 (UTC)[reply]

I'd guess it's so they can increase their profits by selling you a part you'll never need. --76.71.6.254 (talk) 23:05, 19 April 2017 (UTC)[reply]

Just because you would never use doesn't mean someone else wouldn't. The world doesn't consist only of you and people whose needs and wants and preferences match exactly yours. --Jayron 32 03:01, 20 April 2017 (UTC)[reply]

Could they function as safety glassess ? StuRat (talk) 02:31, 20 April 2017 (UTC)[reply]

Jellyfish evolving into land creatures

What would jellyfish look like if they evolved into land creatures? Has anyone speculated? I tried doing a Google search but I didn't come up with muchUncle dan is home (talk) 20:23, 19 April 2017 (UTC)[reply]

Surely this question is inviting only speculation - not appropriate for a ref desk in my opinion. DrChrissy ^(talk) 21:23, 19 April 2017 (UTC)[reply]

There are at least potential sources for similar questions - see The Future Is Wild. Speculative evolution seems to be a field, so while there is speculation evolved, it's not necessarily speculation by the refdesk. --Stephan Schulz (talk) 21:27, 19 April 2017 (UTC)[reply]

Agreed, it is perfectly reasonable in these circumstances to link to published speculation as a reference on prior (presumably informed) speculation. SemanticMantis (talk) 22:46, 19 April 2017 (UTC)[reply]

Jellyfish need a fluid so they can float. If they where big they might float in air if they could produce and contain a gas lighter than air but then how would their offspring manage that? Maybe they could rise from a lake. Anyway they would not work as land creatures. --Kharon (talk) 21:45, 19 April 2017 (UTC)[reply]

Such creatures have featured in several science fiction stories and novels set on alien planets. The terrestrial (in the planetary sense!) Portugese man-o-war looks as if it's part of the way there. {The poster formerly known as 87.81.230.195} 90.217.249.244 (talk) 02:48, 20 April 2017 (UTC)[reply]

I want to see octopuses evolve into land animals. And gain sentience and see what their chairs look like. Sagittarian Milky Way (talk) 22:07, 19 April 2017 (UTC)[reply]

Octopi can work on land. There was a video a year or so ago showing an octopus crawling up on a rock and grabbing a crab. Also, see SPECTRE. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:12, 19 April 2017 (UTC)[reply]

Well I better not speculate so I'll just point to where the ideas here have been investigated :) How about jellyfish not just on land but in space? And don't Pastafarians have a deity rather like a very intelligent octopus with lots more arms? I believe it resides on a plate rather than sitting in a chair. Dmcq (talk) 22:35, 19 April 2017 (UTC)[reply]

Why does Defibrillator has two stickers to attach the chest of a victim?

Why does Defibrillator has two stickers to attach the chest of a victim? Is one is not enough in order to deliver dose of energy / electricity? 93.126.88.30 (talk) 22:02, 19 April 2017 (UTC)[reply]

See Defibrillation. An electrical current must flow between two points. In general this cannot happen if you have a single electrode. -Arch dude (talk) 22:13, 19 April 2017 (UTC)[reply]

In an electric circuit, current flows between two electrodes, the cathode and the anode. Electricity isn't some kind of fluid that you can just pump into a person. CodeTalker (talk) 22:15, 19 April 2017 (UTC)[reply]

For a layerson's description of how a defibrillator works see https://www.howequipmentworks.com/defibrillator/ Richerman (talk) 22:27, 19 April 2017 (UTC)[reply]

By the way the person being treated with a defibrillator is usually called a patient rather than a victim. Dmcq (talk) 22:39, 19 April 2017 (UTC)[reply]

Interestingly, if a person is laying on the ground it would be possible to use only one electrode as the earth itself would complete the circuit (thinking to why people can get electrocuted from power lines where birds do not). But completing the circuit with two pads gives you much more control of where the energy goes (through the heart), along with reducing resistance which can cause burns which is why they typically use a conductive gel. Drewmutt (^ᴥ^) talk 22:47, 19 April 2017 (UTC)[reply]

the person may be grounded, but the portable defi isn't, so coming in contact with just one pad should be safe (insert disclaimer.) IOW, it's not about having a definite return path (instead of through the person's shoulderblades, bum etc), it's about having any return path at all. Asmrulz (talk) 05:32, 20 April 2017 (UTC) [reply]

Yeah you wanna make sure the current is through the heart not from the chest to ground. The term 'victim' (by another poster really made me laugh though). Keep it up RD posters: (its the best comedy channel on the internet, especially with some of the regulars posting their 2 cents worth). 31.109.117.25 (talk) 00:11, 20 April 2017 (UTC)[reply]

Just to understand and to make it clear, I would like to know if in AEDs normally there is a pad for right and a pad for left or it doesn't matter? [Regarding to using of "victim", it may-be mistake but it may-be a meter of difference between the AmEn to BrEn and AUen and CaEn. I don't belong to one of them but still I found it a lot in what called "high education" lectures or official sites, books, Googling (AED + victim) can show a plenty of examples).] 93.126.88.30 (talk) 03:30, 20 April 2017 (UTC)[reply]

perhaps they don't want to imply a doctor-patient relationship or something, AEDs being one of those apparatus that may be used by laypersons Asmrulz (talk) 05:32, 20 April 2017 (UTC)[reply]

Near Earth object flybys and statistical oddities

This shows a best fit power law of 19 absolute magnitudes of size cutoff reduction resulting in 9 orders of magnitude higher frequency of hitting the Earth. Or 2.97635144 times more asteroids per 1 absolute magnitude dimmer size cutoff. The nearest might be sqrt(2.97635144) times closer to the center on average and thus 2.97635144 divided by the 1 astronomical magnitude (2.51 times) dimmer asteroid still makes it 1.184 magnitudes brighter from the center and even more from parts of the Earth closer to it than Earth's center. So does that mean the brighter (apparent magnitude) a near Earth asteroid flyby is (from either Earth's center or the best place in the world), the more likely it is to be smaller and closer than bigger and farther? Are apparent magnitude 10 asteroid flybys more likely to be less wide than expected through the expedient of higher albedo? But if so the chart seems to say the power law holds for both width and absolute magnitude. Is there a name for this statistical oddity? Sagittarian Milky Way (talk) 23:24, 19 April 2017 (UTC)[reply]

P.S. Can someone explain why the apparent magnitude link doesn't lead to the apparent magnitude article? Sagittarian Milky Way (talk) 23:29, 19 April 2017 (UTC)[reply]

so why dont you bledinmg well link it then??? — Preceding unsigned comment added by 31.109.117.25 (talk) 00:16, 20 April 2017 (UTC)[reply]

Cause if our universe is a computer simulation and I'm being screwed with I don't want to know. Sagittarian Milky Way (talk) 01:38, 20 April 2017 (UTC)[reply]

The apparent magnitude link works for me, but when I cut and paste yours, it doesn't. I would guess you have an unprintable character in there. StuRat (talk) 00:28, 20 April 2017 (UTC)[reply]

The original "apparent magnitude" link has a U+200B zero-width space at the end. PrimeHunter (talk) 01:26, 20 April 2017 (UTC)[reply]

Yep, that'll do it. How did you find it ? StuRat (talk) 02:20, 20 April 2017 (UTC)[reply]

April 20

@@ Line 394: / Line 394: @@
 :By the way the person being treated with a defibrillator is usually called a patient rather than a victim. [[User:Dmcq|Dmcq]] ([[User talk:Dmcq|talk]]) 22:39, 19 April 2017 (UTC)
 :Interestingly, if a person is laying on the ground it would be possible to use only one electrode as the earth itself would complete the circuit (thinking to why people can get electrocuted from power lines where birds do not). But completing the circuit with two pads gives you much more control of where the energy goes (through the heart), along with reducing resistance which can cause burns which is why they typically use a conductive gel. [[User:Drewmutt|Drewmutt]] <span style="color:#01B0F0;letter-spacing:-2px">(</span><span style="color:#FF358B">^ᴥ^</span><span style="color:#01B0F0;letter-spacing:-2px">)</span> [[User talk:Drewmutt|<span style="color:#F2813D;font-size:10px">talk</span>]] 22:47, 19 April 2017 (UTC)
+::<small>the person may be grounded, but the portable defi isn't, so coming in contact with just one pad should be safe (insert disclaimer.) IOW, it's not about having a definite return path (instead of through the person's shoulderblades, bum etc), it's about having any return path at all. [[User:Asmrulz|Asmrulz]] ([[User talk:Asmrulz|talk]]) 05:32, 20 April 2017 (UTC) </small>
 :Yeah you wanna make sure the current is through the heart not from the chest to ground. The term 'victim' (by another poster really made me laugh though). Keep it up RD posters: (its the best comedy channel on the internet, especially with some of the regulars posting their 2 cents worth). [[Special:Contributions/31.109.117.25|31.109.117.25]] ([[User talk:31.109.117.25|talk]]) 00:11, 20 April 2017 (UTC)
 :::Just to understand and to make it clear, I would like to know if in AEDs normally there is a pad for right and a pad for left or it doesn't matter? [Regarding to using of "victim", it may-be mistake but it may-be a meter of difference between the AmEn to BrEn and AUen and CaEn. I don't belong to one of them but still I found it a lot in what called "high education" lectures or official sites, books, Googling (AED + victim) can show a plenty of examples).] [[Special:Contributions/93.126.88.30|93.126.88.30]] ([[User talk:93.126.88.30|talk]]) 03:30, 20 April 2017 (UTC)
+::::perhaps they don't want to imply a doctor-patient relationship or something, AEDs being one of those apparatus that may be used by laypersons [[User:Asmrulz|Asmrulz]] ([[User talk:Asmrulz|talk]]) 05:32, 20 April 2017 (UTC)
 == Near Earth object flybys and statistical oddities ==