Wikipedia:Reference desk/Archives/Science/2018 June 9

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June 9

X polysomy

I have seen the following question on internet and the answer is A: "Clinical presentations of a woman allowed provisionally diagnosing her with X polysomy. Cytogenetic method is applied to clarify the diagnosis. The diagnosis will be confirmed if the patient’s karyotype is: A. 47, ХХХ B. 48, XXXY C. 48, XXYY D. 47, XXY E. 46, XX". My question why is this (47, XXX) the answer? why it cannot be XXY for example? (Based on this article: "45,X, 47,XXX, 47,XXY, and 47,XYY collectively occur with an incidence of approximately 1 in 400 newborns"). --93.126.116.89 (talk) 01:27, 9 June 2018 (UTC)

It isn't a great question IMO. But read the question especially the first few words and your source carefully. Of if your source isn't clear enough for you, try our articles XXXY syndrome+Klinefelter syndrome and Triple X syndrome or these two sources [1] [2]. Remember also with MCQs you should always choose the answer which best fits, regardless of whether you can argue another answer also fits. Nil Einne (talk) 05:16, 9 June 2018 (UTC)

Maybe see also [3] [4]. In the particular case of XXY, it's perhaps also worth considering the technicalities of the definition of Polysomy and so X Polysomy (as opposed to sex chromosome polysomy). Nil Einne (talk) 11:00, 9 June 2018 (UTC)

The word "woman" rules out all the answers that have a Y in them. If there is a Y chromosome, you have a man. Looie496 (talk) 14:16, 9 June 2018 (UTC)

That's true. Thank you!--93.126.116.89 (talk) 16:10, 9 June 2018 (UTC)

Normally, but not always, true. The Y chromosome (normally) carries an active SRY gene, the X carries an inactive version. People can have a XY karotype, but with an inactive SRY gene. They are physically female; this is called Swyer syndrome. Likewise people can have an XX karotype, and be physically male; this is called XX_male_syndrome. ---- 20:46, 9 June 2018 (UTC)

Ecoregions

Where can I find a map which shows both the ecoregions of the United States and southern Canada (as defined by the EPA)? 2601:646:8A00:A0B3:75BF:B7E1:4F33:DA1C (talk) 09:25, 9 June 2018 (UTC)

I think the resources on this page will be more or less ideal to your needs. Incidentally, the EPA's mandate pertains to domestic policy only, for the most part, so it is doubtful that the cash-strapped and heavily constrained agency spends a whole lot of effort surveying the bioregions of other countries (where they are not contigous with the U.S. or are at least somehow marginally relevant to a regulatory scheme), except for the fact that they coordinate with the Commission for Environmental Cooperation to compile their own data on region identification with that of their counterparts in Canada and Mexico. So the better article for you on the topic is List of ecoregions in North America (CEC). Though, again, the maps you specifically requested are found at the external EPA-hosted link. I must admit, I am getting lost in them myself right now. Snow ^{let's rap} 09:49, 9 June 2018 (UTC)

Perfect! I was looking for some way to find the ecoregions of all the places I've ever been! Just one question, though: Is Vancouver considered part of ecoregion 7.1.6 (Pacific and Nass Ranges), or 7.1.7 (Strait of Georgia/Puget Lowland)? 2601:646:8A00:A0B3:D47E:7D12:20FE:2672 (talk) 02:14, 11 June 2018 (UTC)

At maximum zoom, the Level III map seems to put it distinctly within 7.1.7 but not terribly far from 7.1.6. But ecoregions are by their nature such fuzzy concepts that when you are that close to the border, any call could be reasonably considered a technicality, if you ask me. Snow ^{let's rap} 08:01, 12 June 2018 (UTC)

Thanks! Whereas Seattle is unambiguously within 7.1.7 -- right? 2601:646:8A00:A0B3:B9F2:AB80:DC96:9320 (talk) 10:34, 12 June 2018 (UTC)

You're welcome. And yes, that does seem to be the case. Snow ^{let's rap} 13:43, 13 June 2018 (UTC)

Thanks again! And, to continue with this question: Which ecoregion is Door County, Wisconsin? (I haven't been there, and don't plan on going in the near future, but I'm just curious.) 2601:646:8A00:A0B3:7158:3B89:88CF:A2DC (talk) 06:23, 15 June 2018 (UTC)

It appears to be in Ecoregion 8, in the subsection called Cheeseheadia. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:55, 15 June 2018 (UTC)

Cheeseheadia??? I see the Driftless Area, I see the Michigan/Indiana Drift Plains, I see the North Central Hardwood Forest, but I don't see no region on the map labeled "Cheeseheadia"! 2601:646:8A00:A0B3:7158:3B89:88CF:A2DC (talk) 09:11, 15 June 2018 (UTC)

Ecoregion 8.1.4, within the land of the Cheesehead. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:02, 15 June 2018 (UTC)

Main Battle Tank

Hello , I once saw a video on Youtube by an unknown person that says that there was an incident in which an M1 tank was passing over a bridge in Iraq and the bridge collapsed due to the extreme weight of the tank . My first question is that true ? My second question if that was true then can we conclude that all 70 ton tanks which are the Abrams ,the challenger 2 and the Leopard 2 cannot be delivered to the cities of middle eastern countries ? 149.200.165.63 (talk) 14:46, 9 June 2018 (UTC)

• Heavy equipment including tanks have been collapsing bridges and other structures since their invention, whether or not this particular incident occurred. No you cannot conclude that all MBTs are unusable in all cities. The engineers can in general figure out something. I suspect that narrow streets are a more universal problem than weak bridges. -Arch dude (talk) 16:29, 9 June 2018 (UTC)

I'm disinclined to believe this anecdote unless evidence is presented. People who drive tanks literally go to school where they learn not to drive the 70-ton, $10-million weapon system into an easily-avoidable hazardous situation. Combat engineers are probably the greatest experts in the world when it comes to the science and practical engineering of evaluating whether a bridge is sturdy enough to use for a specific purpose, like supporting a 70-ton armored vehicle during combat. Neither bridges, nor the waterways and land features they bridge across, spring up unexpectedly; during planning of a strategic or tactical deployment, a commander would generally know in advance whether a bridge needs to be crossed, or built, or inspected, before sending the armored unit in. There are entire agencies of the United States Government whose sole purpose is to accurately map the geography, and the bridges and transportation infrastructure, of every part of this planet - so there should be no reason for a tank crew to become surprised when they encounter an unexpected weak bridge as they sally forth on their merry way to warfare.

A lot of people would have to be sleeping on the job for an American tank to drive onto a bridge and then cause the bridge to collapse.

Here's a review thesis, The Relevance of Armor in COIN, which I found on the CARL library website. In thirty pages of summary of American armored forces in Iraq, there is no mention of an accident while operating on a bridge.

There was an accident in the very first days of the Iraq war in which an M1A1 operated by the Marines drove off a bridge in Nasiriya. The bridge did not fail. Evidently, somebody - the driver - fell asleep on the job.

Nimur (talk) 18:33, 9 June 2018 (UTC)

Great so it`s not an issue of weight , thanks for help both of you .212.34.7.236 (talk) 21:04, 9 June 2018 (UTC)

Cardiac arrests

Does the heart ever just completely stop suddenly or does it always go into ventricular fibrillation first? If it can, does defibrillation do anything in such scenarios? 90.192.115.154 (talk) 16:06, 9 June 2018 (UTC)

https://health.stackexchange.com/a/15131/856 Count Iblis (talk) 16:11, 9 June 2018 (UTC)

Is syn-Propanethial-S-oxide stable enough for it to be stored for some time at room temperature?

syn-Propanethial-S-oxide is formed when onions are cut, it causes our eyes to water. The question is if it is possible for large quantities of this compound to be stored in a pressurized cylinder for use as a non-lethal chemical weapon? Count Iblis (talk) 17:10, 9 June 2018 (UTC)

It dimerizes (doi:10.1021/ja960722j). DMacks (talk) 20:43, 9 June 2018 (UTC)

Non-lethal? It would never be possible to rule out that a death might result. Akld guy (talk) 20:12, 11 June 2018 (UTC)

Why are so many places' all-time record high temperatures near the world record?

So many places have been within a handful of degrees of the highest reliable temperature of 129.2°F. There doesn't seem to be a weather station with a big advantage over the rest of the world. Is there a physical reason for this given the current configuration of the continents? (that the Mediterranean shore would be kilometers lower if Africa moved enough to close the Strait seems to suggest plate tectonics that enable desert kilometers below sea level isn't exceptional (mediocrity principle). If the watershed was a little more south at Sahara latitudes instead well the lowest point is 17,280 feet below sea level. Which I assume would enable sick lapse-rate induced temperatures that make Death Valley look like an air conditioner) Sagittarian Milky Way (talk) 23:16, 9 June 2018 (UTC)

If the air were hot at the surface it would absorb lots of watervapor, get less dense, and buoyantly shoot up until it cooled and formed clouds. Neat negative feedback. It does rely on there being water to absorb. Cites? any thermodynamics transport tables. http://admin.cambridge.org/academic/subjects/engineering/thermal-fluids-engineering/thermodynamic-tables-si-metric-units for example. Greglocock (talk) 23:31, 9 June 2018 (UTC)

Adiabatic lapse rate can give us a reasonable estimate of temperature when heat is mostly exchanged with the surroundings by air flowing in or out of the valley. When an area has a very large surface area compared to its circumference, like the dried-up Mediterranean, heat exchange largely happens through radiation directly from or to space, which doesn't strongly depend on elevation (elevation can have some influence on this via the greenhouse effect). Our article on Messinian salinity crisis#Relationship to climate says the the climate in the dried-up Mediterranean is unknown and mentions temperatures up to 80°C due to lapse rate, but is unsourced. Outgoing radiation increases with the fourth power of absolute temperature, which is fast and makes it hard to get temperatures much above the equilibrium temperature as expected from radiation alone. Those extremely hot places like Death Valley and the Danakil Depression are all relatively small, so that heat is largely exchanged via wind. Now if you find some 4000m deep valley that's only 40km wide, you can expect some extreme temperatures, but such valleys may be rare. PiusImpavidus (talk) 10:32, 10 June 2018 (UTC)

I guessed the fourth power law might be at least part of it. The Death Valley weather station is only ~0.08 kilometers below sea level so per dry adiabatic lapse rate that should only give it about a 0.8°C advantage over sea level deserts which isn't a lot. The Dead Sea's lower but perhaps the geography of the area might not be as favorable? (is it Israel mountains protecting it's basin less than California? Mediterranean moisture rains in Jerusalem enough to farm after all and its basically the brim of the Dead Sea depression) Sagittarian Milky Way (talk) 16:05, 10 June 2018 (UTC)