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July 24

Removing water to connect all current land...

How much would the sea level have to drop to have all *current* above the water land to be connected by land? And what would be the last piece of current land to be connected?Naraht (talk) 15:14, 24 July 2018 (UTC)

Does that include middle-of-the-ocean features such as Hawaii? ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:31, 24 July 2018 (UTC)

Yes. And Pitcairn, Bermuda, Kerguelen, etc....Naraht (talk) 15:33, 24 July 2018 (UTC)

To connect Mauna Kea to mainland, you would have to drain several miles of water. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:47, 24 July 2018 (UTC)

Any idea how to get more accurate information? (A decent map of depths of the Pacific would probably help, but I haven't found a great one) For Hawaii, it is entirely possible that the land bridge that gets revealed connects Mauna Kea to Kamchatka along the Hawaiian–Emperor seamount chain, but I'm not sure on the depths of some of the gaps in the chain?Naraht (talk) 18:02, 24 July 2018 (UTC)

In Google Images, there are various topographic maps of the ocean floor. This NG item[1] allows you to look at portions of it. The Hawaiian Ridge is a series of volcanoes which go way down deep, as are many of the other Pacific islands. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:33, 24 July 2018 (UTC)

Agreed, but the question is whether there are gaps in the Hawaiian-Emperor that go all the way down to the general seafloor or whether it stays significantly above that level as is true between Hawaii and Oahu.Naraht (talk) 19:46, 24 July 2018 (UTC)

You can download a detailed (30 arc second) grid of global bathymetry from GEBCO here. With the appropriate software you could mess about with a colour bar until you found what you were looking for. Mikenorton (talk) 19:57, 24 July 2018 (UTC)

In case you didn't know: Puerto Rico is surrounded by water. 2600:8806:4802:C700:19EF:9053:95DC:1C0A (talk) 21:05, 24 July 2018 (UTC)

Thanks, Donald. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:15, 24 July 2018 (UTC)

A related question [2].--Wikimedes (talk) 05:48, 25 July 2018 (UTC)

How do weeds manage to grow without a drop of water in the soil?

Not a drop of rain in two months, and yet I have to remove weed in the garden. I need to water the plants to prevent them from drying out in these extremely dry conditions, yet the weeds germinate and grow. How do these plants get enough water? Count Iblis (talk) 15:48, 24 July 2018 (UTC)

It's at least partly a circular problem: plants are called weeds because they grow where they're not supposed to. Plants with higher tolerance for dehydration would have an advantage filling that niche, so it makes sense that many weeds would survive/thrive while other plants dried out and died - if they didn't, they wouldn't out-compete your tomatoes and dahlias. So what makes them dehydration tolerant? Well, there are many adaptations that will play a part (pore placement and density, gross morphology, waxy coatings, the use of taproots, and so on. Weeds rarely spend a lot of energy on fleshy fruit or showy blooms (though there are some exceptions), and that also reduces their need. Matt Deres (talk) 16:21, 24 July 2018 (UTC)

Are you sure they're not coming up from the roots of weeds you've previously tried to remove? Anyway I've heard weed is associated with Satanism so it must be able to cope well with the heat ;-) Dmcq (talk) 16:24, 24 July 2018 (UTC)

There are indeed plants with deeper roots, but I'm puzzled about new weeds that germinate and have tiny roots when I pull them out. Somehow these tiny roots were able to extract water from the bone dry soil. So, it must be what Matt Deres says about losing less water than other plants, but there must also be mechanisms that allow water to be extracted from the top layers of the soil. Perhaps some of the water at greater depths in the soil evaporates and at night when the top layers of the soil cool down, the water vapor makes it there via pores and condenses there? Count Iblis (talk) 17:17, 24 July 2018 (UTC)

I suppose some weeds are better at conserving water but I think most just are far better at extracting the water and leaving the soil too dry for other plants - it is a major way they outcompete other plants I believe. Dmcq (talk) 17:50, 24 July 2018 (UTC)

If actual data doesn't match your assumption, it is quite likely your assumption is wrong. You have assumed the soil has zero water. Plants are growing in it. Therefore, your assumption is wrong. To have assumptions impervious to contrary evidence is a problem... --Jayron32 18:02, 24 July 2018 (UTC)

One way to get water in the top of the soil is via dew or frost. Before sunrise the soil surface may be moist, but when you look in the afternoon all that moisture may have evaporated. Graeme Bartlett (talk) 03:11, 25 July 2018 (UTC)

Thanks everyone for their input in this thread! Count Iblis (talk) 19:26, 30 July 2018 (UTC)

Deploying Compost in Extreme Heat.

I know that in the UAE and Saudi Arabia when farmers plant they have little water retention in sandy soils. Why cant they just compost all the organics from the big cities or ship in organics from other places for composting and plant in that. Is there something specific that happens to high organics soils(IE. Compost) when it is exposed to dry heat? Is this sustainable. Looking for someone to prove sustainability or not. If you have questions on more info Please Ask. — Preceding unsigned comment added by Mason201 (talk • contribs) 17:10, 24 July 2018 (UTC)

[ http://hal.cirad.fr/docs/00/18/03/35/PDF/Bahri.pdf ]

Abstract:

Water reuse in Tunisia: Stakes and prospects. In the arid and semi-arid region, countries like Tunisia are facing increasingly serious water shortage problems. According to forecasts, increased domestic and industrial water consumption by the year 2020 may cause a decrease in the volume of fresh water available for Tunisian agriculture. It is therefore important to develop additional water resources as well as protect the existing ones. One way to cope with these problems is to reuse wastewater in agriculture. Therefore and before launching the water reuse policy, a research program was undertaken...

--Guy Macon (talk) 17:44, 24 July 2018 (UTC)

Composting requires the presence of air. Water is needed in the right amounts to maintain activity without causing anaerobic conditions; the air/water balance is critical to maintaining high temperatures (135°-160° F / 50° - 70° C) until organic solid wastes decompose. Urine, itself useful as a nitrogen-rich fertilizer, is a suitable additive to a compost pile. DroneB (talk) 17:46, 24 July 2018 (UTC)

In addition to that, an obvious question is, why compost in the desert anyway? I mean the idea of composting waste from their own cities may make some sense. But what's the purpose of shipping in organic waste from elsewhere? Maybe you've never composted but if you ever did you'd know that the volume of what you start with is a lot more than what you end up with. [3] So there are at least 2 and probably more (shipping organic waste around seems a good way to ensure lots of problems with pests etc) problems with shipping in the waste and composting it on site. If the idea made any sense, it would seem better to simply compost it somewhere else and ship in the compost. BTW perhaps Desert greening will be of some interest. You'd note that it doesn't really mention shipping in compost or soil at massive scale as part of the process. Nil Einne (talk) 23:05, 24 July 2018 (UTC)

Insect from eastern Quebec

Graceful insect

Hello. Can you identify this little fellow who landed on my front door this morning (or last night..). I live in Rimouski suburb, Quebec Canada, in an open landscape of bungalows, many trees and several patches of mixed forest, a few hundred meters of St-Lawrence estuary. Body length : 1cm, wings span 2,5 cm. Thank you. Dhatier (talk) 17:45, 24 July 2018 (UTC)

I'm pretty sure it's a type of paleoptera (i.e. mayfly, dragonfly, or damselfly), though a rather more ornate one than I have ever seen. Maybe that will lead you in the right direction, though there are thousands of different species. --Jayron32 18:12, 24 July 2018 (UTC)

Looks like a rose plume moth Cnaemidophorus rhododactyla. Mikenorton (talk) 18:19, 24 July 2018 (UTC)

Agreed. T shapes are usually some sort of plume moth (although our local ones are ghostly white). Andy Dingley (talk) 18:30, 24 July 2018 (UTC)

Cnaemidophorus rhododactyla confirmed by numerous images on Google. Thank you very much. Dhatier (talk) 18:45, 24 July 2018 (UTC)

July 25

Why can Labrador get so hot?

North West River Northwest River
The highest known North American temperature east of Ontario and New York happened here in 1914.
Coordinates: 53°31′31.32″N 60°08′41.80″W

List of extreme temperatures in Canada. Also has exceeded the all-time highs of DC, Philly, Toronto, Ottawa, Windsor, Detroit, O'Hare, Indianapolis and Columbus and only 0.9F less than Ontario (108F). Sagittarian Milky Way (talk) 22:48, 25 July 2018 (UTC)

Not a complete answer, but there were heat records in many parts of the world this year, with a crisis in Japan at the moment. Co2 levels also fluctuated less, remaining high (with average level higher every year). Extreme weather events are predicted to rise as global warming pursues. Forest fires are regular in many areas and increasing, dumping more Co2 and the warming of permafrost is a concern as more methane is not converted before reaching the surface (with a temporary effect higher than that of Co2). There are fears about reaching tipping points and it's very difficult to determine when one will be attained; runaway changes are considered possible when one or more such tipping points are reached. About Labrador this year specifically, I'll let others expand (obviously, specific events cannot directly be linked to global trends). —PaleoNeonate – 23:28, 25 July 2018 (UTC)

The highest known temperature east of Ontario and New York was not only so far north but also outside the modern warming era or the Dust Bowl which makes it even more unusual. Sagittarian Milky Way (talk) 00:40, 26 July 2018 (UTC)

I am intensely skeptical of that information. The table with that value was added on March 21 of this year, with no sources, by an editor who has repeatedly run into trouble due to adding unsourced information to articles. It is not uncommon for locations that are far inland to reach very high temperatures, even if they are far to the north, but for a coastal location to reach such a temperature would really be anomalous. Anything is possible, of course, but I would like to see some evidence. Looie496 (talk) 03:06, 26 July 2018 (UTC)

There really seems to be a record of that temperature, the Canadian government list it [4]. There is some similar scepticism of that temperature in this discussion [5] (which was how I worked out to use that site) and [6]. Nil Einne (talk) 12:18, 26 July 2018 (UTC)

Further found [7] and sort of [8]. This post in the first discussion [9] is most interesting as it includes a response from Environment Canada which included an image of the original paper record [10] confirming it's not simply a modern data entry error. (Although IMO one of the responses in that thread is a little harsh. It sounds like whoever responded primarily felt they were being asked if there was some data entry error and confirmed there wasn't with the original records. They may not have felt it worthwhile going through the process of annotating or removing a single potentially spurious record.) BTW, in case there is some remaining confusion because of PaleoNeonate's post, we aren't AFAIK talking about anything this year or as SMW said anywhere close to modern times but a record from 1914. Nil Einne (talk) 12:39, 26 July 2018 (UTC)

Wow. I still think there must be an error somewhere, though. As one of those linked posts says, if the high was 65 the day before and the day after, and it rained on that day, it's very difficult to imagine how the temp could have reached 107. Looie496 (talk) 14:04, 26 July 2018 (UTC)

One thing to remember is that climate is complex, and that temperatures (both averages and extremes) are only partly a function of latitude. You can see this sort of thing at U.S. state temperature extremes. The state with the lowest record high temperature? Hawaii. The state closest to the equator. This is true because temperature is a factor of many things, besides latitude there are wind currents, proximity to large bodies of water, temperature of that water, local terrain, elevation, etc. etc. Microclimates can also be similarly weird; one of the most famous microclimates in North America is San Francisco, which is frequently 10-20 degrees F colder than places only a few miles away; (There's a frequently mis-attributed aphorism that goes "The coldest winter I ever saw was the summer I spent in San Francisco") the average July high is 66.5F for San Francisco, and 72.0F for Oakland, a 5.5F difference is impressive given that the cities are connected by a bridge. All that goes to say that simply being far in the north does not disqualify some specific location in Newfoundland from having some unusual microclimate, given the variety of factors at play. --Jayron32 15:20, 26 July 2018 (UTC)

It might be useful to examine the temperature records of adjacent stations, also newspapers covering the area - these often contain a day-to-day weather record. See List of newspapers in Canada. Here are the figures for five stations in the area:

Date                  Station          Max (°C.)                       Min. (°C.)            
1914 August 11        Burin            23.9                            12.8
                      Fogo             23.3                            15.6 
                      North West River 41.7X                           10.0
                      St Georges       24.4                            15.6
                      St John's        23.9                            19.8

You will note the red "X" against the North West River maximum. This suggests it was picked up as an anomaly at the time. 86.133.26.146 (talk) 17:32, 26 July 2018 (UTC)

There is also a red X by the original data record for "107" above. Also note there is a column "Range" to the right, which has an entry "57" (which is "107" - "50"). The weather was given as some letter, which I assume means clear, for the morning, with "overcast" in the afternoon, and "rain and heavy thunderstorm" as a note. Which is what you'd expect with that kind of high temperature! Finally, note the sequence of high temperatures: 97 62 63 71 70 64 65 66 75 107+ 65 86 76 62 63 65 63 65 50 49 68 65 63 74 78 74 . Putting those in LibreOffice Calc and doing STDEV.S(that range of values) I get 12.41, which sounds at least about right. The average is 69.46, so this value is at 3.02 standard deviations out. That means there is only a 0.27% (1/370) chance of such a value occurring, according to standard deviation. (It seemed faster to check that table than remember the function name...) Nonetheless, in a dozen such months, one time it could happen by chance. The value is still suspect, of course, because any 1% chance of error is more likely than that it is correct (that is, until you read the post above; with confirmation, its chance of being correct is much higher than the 1% error) -- but we certainly don't know it is wrong. Wnt (talk) 22:27, 26 July 2018 (UTC)

To me it looks more like a + or straight cross than an x unless it was added at an extreme angle. See also this rotated version. [11]. I was thinking of it before and it seems to be a clear highlighting. But whether it was intended to indicate the value was in doubt or could be an error or an anomaly, or simply noting it was unusual high or maybe that it was the highest value, I'm not sure. I'm leaning towards it simply being because it's the highest value. There look to be two bars which similar denote the lowest minimum values. I was originally confused about these because I thought they were underlining two random values with nothing special. But looking more carefully I realised they are probably a bar above the two 38 values which are the lowest minimum values for that month. Nil Einne (talk) 10:21, 27 July 2018 (UTC)

Not sure why this doesn't break the Second Law of Thermodynamics

I'll assume it doesn't, but I can't see why. Advice welcome, I've been scratching my head for a decade.

Imagine the Earth were so far from the Sun, that there was no solar heating, and it had no internal radioactive decay ; would its atmosphere ( probably needing to be only Helium, to be a gas at 6 Kelvin ) be the same temperature on the surface, as at say 10 kilometres altitude ? If so, how would a molecule of air moving vertically, in the Earth's gravitational field, keep the same kinetic energy ( and hence velocity and hence temperature ), as it gained or lost the gravitational potential energy, of that 10 km of height ? Air molecules may well interact, sharing and equalising their kinetic energy ; but over any finite change of height, there must be an equal and opposite change of kinetic energy. If this were not true, a molecule of air which was moving upwards, would continue at the same speed, indefinitely, until it escaped to space ; and that would seem to break the even-more unbreakable First Law.

If the gas particles do exhibit "ballistic" behaviour ( like mortar shells ), and this maintains a permanent temperature gradient with height, which could be used to drive a heat engine ; a planet with such an atmosphere, could continuously generate mechanical power, as it absorbed heat energy from the 6 Kelvin afterglow of the Big Bang.

The continuous absorption of heat to generate power, would seem to break the Second Law.

Thanks. GeoffAvogadro (talk) 23:21, 25 July 2018 (UTC)

I think you're getting lost in complexities, but the clean and simple answer is that air temperature decreases with height: this is called the adiabatic lapse rate. The physical reason for this is that at lower altitudes, there is more gravitational potential energy; at higher altitudes, individual molecules have expended kinetic energy to work against gravity.

There are many confounding extra details that make atmospheric science so much fun; but at the basic level, there absolutely is a statistical reduction in kinetic energy for air molecules as their altitude increases.

Above a certain height, the sparsity of the gas molecules becomes very low, and some different properties of thermal and chemical physics begin to dominate: this region is called the ionosphere (and/or the thermosphere, or magnetosphere, depending on which classification scheme you're using; these terms are sometimes used interchangeably, but they actually specify sub-regions that describe the details of the molecules and ions at specific altitudes and atmospheric conditions).

Nimur (talk) 23:34, 25 July 2018 (UTC)

The answer is that in that scenario the entire atmosphere would be in thermal equilibrium with the cosmic background radiation, at a temperature of 2.8 K. But basically there wouldn't be any atmosphere -- even helium would be in a liquid state at that temperature. You would only have a few stray molecules that randomly escape from the surface, hardly denser than outer space. Looie496 (talk) 02:45, 26 July 2018 (UTC)

Helium is a liquid at that temperature at atmospheric pressure. You'd need to check the phase diagram of helium to see what state it would be in at the pressures you are thinking of. Also, if helium is escaping from the surface and dissipating into the atmosphere at a greater rate than it is condensing, it is not in equilibrium; your planet is losing mass, which means even at the same temperature, you're losing thermal energy. --Jayron32 18:03, 27 July 2018 (UTC)

Good point about pressure. Looking at the phase diagrams at http://ltl.tkk.fi/research/theory/helium.html, it appears that at the cosmic background temperature, you could have an atmosphere of up to two Earth-atmospheres in pressure composed almost entirely of ³He, above an ocean of liquid helium. The other stable isotope, ⁴He, would be liquid down to a much lower pressure. Looie496 (talk) 20:42, 27 July 2018 (UTC)

It is true that in the absence of surface heating the atmosphere will gradually become isothermic. So, there is no contradiction with the second law. Molecules going up will be slowed by the gravity but will gain energy in collisions with molecules going down and therefore accelerated by the gravity. This picture is only true on spatial scales above the mean free path length in gas. Below this length the gas kinetic model (and thermodynamics generally) is not applicable and the gas behaves like a cloud of free particles which happens, for example, in exospheres. Ruslik_Zero 06:46, 26 July 2018 (UTC)

Uh, unless there's some subtlety I'm missing here, you couldn't drive a heat engine with the atmospheric temperature gradient because to move the hotter air away from the surface you have to do work against Earth's gravity. Also, I know this is a spherical cow kind of thought experiment, but as Looie496 noted, at that temperature you'd just have frozen volatiles on the planet's surface, with a tiny amount of sublimated vapor, as seen on worlds like Pluto. And there'd be no appreciable amount of helium; Earth's gravity is too weak to hold on to hydrogen or helium. --47.146.63.87 (talk) 06:59, 26 July 2018 (UTC)

I thought that the cosmic background radiation plus starlight gave a higher equilibrium temperature than the cosmic background radiation alone. Obviously this would differ (in the galaxy core? in the empty spaces between galaxies? Any large clouds nearby?) but the interesting number would be for a planet in the spiral arm, roughly where our sun is. --Guy Macon (talk) 06:59, 26 July 2018 (UTC)

The vast majority of cosmic rays originate from outside our own galaxy. The intensity may actually increase as you move to regions of lower stellar density, due to reduced shielding from cosmic rays by stellar magnetic fields. Someguy1221 (talk) 22:28, 27 July 2018 (UTC)

"Cosmic background radiation" properly refers to the relic radiation from photon decoupling that pervades the universe. This is what the original poster was referring to. I don't doubt sometimes the term is used sloppily to include cosmic rays, but in strict scientific terms this is wrong, as they're two totally different things. --47.146.63.87 (talk) 06:39, 28 July 2018 (UTC)

Nah, i just had a total brain fart reading Guy's post, and thought he wrote 'cosmic rays'. Someguy1221 (talk) 19:32, 28 July 2018 (UTC)

Yes, obviously this depends on distance. Pluto for instance gets down to about 33 kelvin; the heat sources are a mixture of the Sun's heat, Pluto's internal heat, and probably some tidal flexing from Charon. --47.146.63.87 (talk) 06:39, 28 July 2018 (UTC)

Assuming the background temperature was enough to keep helium a gas then the temperature of the air would be the same at all heights. It being different on earth is because the earths atmosphere is nowhere near an equilibrium, we have the sun shining down and various interactions between the gas and the radiation. The energy of the molecules would get spread out, they don't just fall from space to the ground. Just having molecules falling straight up and down isn't a stable equilibrium. Dmcq (talk) 11:37, 26 July 2018 (UTC)

July 26

Stomach usually gurgles on the left side

This question is not for diagnosis but for curiosity. I hear that my stomach usually gurgles on the left side rather than on the right. Why most of the gurgles occur on the left side rather than about the same on both sides? PlanetStar 05:32, 26 July 2018 (UTC)

Your stomach is mostly on the left side of your body. --76.69.47.228 (talk) 05:47, 26 July 2018 (UTC)

But the gurgles sometimes occur on the right side of the abdomen. The stomach were referring to is a bean-shaped organ above the intestines. The gurgles doesn't just occur in the stomach, it also occurs in the intestine, which is evenly spread from left to right. Maybe most gurgles occurring on the right side is intestinal gurgles, but maybe most intestinal gurgles occur on the left side; if so, what's the cause of occurring mostly on one side of the intestine? PlanetStar 04:33, 27 July 2018 (UTC)

I suppose that what is gurgling is not the stomach as a whole but the pylorus, which is clearly located on one side of the body, by most humans the right one. Maybe you have it on the other side? Also gurgling of the intestine is possibly not evenly distributed but happens e.g. only at the interface between colon and ileum, or only in its descending or ascending but not horizontal segments. 194.174.76.21 (talk) 16:07, 27 July 2018 (UTC) Marco Pagliero Berlin

Not eating or drinking before surgery

A family member had to have several minor surgeries, I made a comment to the doctor that "your instructions said no food or drink after midnight for a 7AM surgery, and later we got the exact same instructions for a 5PM surgery." To his credit, he listened and now gives the instruction "no food for ten hours before the surgery, and no water for four hours before the surgery". Needless to say, we follow the instructions no matter what they are. Only an idiot ignores doctors orders.

This got me to thinking and researching. I believe that these restrictions are to reduce the chance of you vomiting while under anesthesia and then sucking some of that stomach acid down your windpipe. So has anyone done a study about how long food and water stay in the stomach? And does the sphincter valve that empties the stomach slowly meter out the contents to the intestines or does it let the stomach work on the food for a while and then dump the result into the intestines? Please note that I am asking for sources, not opinions. --Guy Macon (talk) 06:53, 26 July 2018 (UTC)

You are correct about the purpose: see nil per os and aspiration pneumonia. Chyme states, with no given source: Depending on the quantity and contents of the meal, the stomach will digest the food into chyme in anywhere between 40 minutes to a few hours. However, you can vomit material from the small intestine if vomiting is sufficiently vigorous; such vomiting can often be identified by the presence of greenish bile in the vomit. It sounds like they want all food to have passed into the large intestine. --47.146.63.87 (talk) 07:10, 26 July 2018 (UTC)

Thanks! Good info. I see that Nothing by mouth says "The American Board of Anesthesiology recommends that patients should not eat solid food for at least 8 hours prior to a procedure, and should not drink even clear liquids for at least 2 hours prior". Looks like the doctor added a couple of hours to that just to be safe. Also, he has you show up two hours before the surgery and they put you on an IV, so from a standpoint of thirst/dehydration its only two hours with no water.

As a passing note, if the stomach empties too quickly after for instance gastric reduction surgery it causes the imaginatively named Dumping syndrome, not a pleasant experience. Richard Avery (talk) 12:30, 26 July 2018 (UTC)

Does anyone know how long it takes for food to get past the "vomiting from the small intestine" state? And whether it can happen under anesthesia? --Guy Macon (talk) 17:42, 26 July 2018 (UTC)

I'm not finding anything definitive and searching has already ruined my lunch. :) I will point out the article on fecal vomiting, which suggests that, in rare cases, there is not really a limit (unless it's already pooped out the other end). Matt Deres (talk) 17:44, 27 July 2018 (UTC)

Small intestine transit time ranges from 15 minutes to 5 hours. In 83% of those studied, transit time was less than 2 hours, and mean transit time was 84 minutes. [12] Probably once you're past the duodenum the exit route will no longer be up. - Nunh-huh 17:58, 27 July 2018 (UTC)

Seeking an identification for this caterpillar found in garden. Somerset UK

Hi folks

I found this caterpillar in the garden this afternoon and I'm hoping someone can identify it. It was about 4 inches inches long and fairly thick. I've attached some pics the last of which was after I had gently brushed against it with a twig, this appears to have made it change it's head shape into something broader and more threatening, as a defensive measure no doubt.

This was all happening in Somerset UK in case that helps identify the creature.

• 
• 
• 
• 

Many thanks Gareth — Preceding unsigned comment added by Hermitical (talk • contribs) 20:18, 26 July 2018 (UTC)

Looks like a Deilephila elpenor, an Elephant Hawk Moth.Mikenorton (talk) 20:52, 26 July 2018 (UTC)

(ec)I googled "caterpillars with segments that look like eyes" an this ite turned up: [13] They actually think it looks like a snake. Be that as it may, they're saying it's the "Deilephila elpenor, known as the Elephant Hawk-moth". ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:53, 26 July 2018 (UTC)

And given Mikenorton's confirmation, it looks like you've got some new illustrations to add to the article! ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:55, 26 July 2018 (UTC)

Many thanks for all your help. It was an incredible sight! Do you really think I should add any/all of these photos to the Deilephila elpenor article? Hermitical (talk) 18:04, 27 July 2018 (UTC)

You could add them to commons:Category:Deilephila elpenor (caterpillar). Mikenorton (talk) 18:30, 27 July 2018 (UTC)

July 27

Definition of episomal

Is it correct to call a non-integrating plasmid episomal if it's in a eukaryotic cell and does not replicate in that cell? Is the ability to replicate in the cell in question necessary to meet the definition of episomal? Thanks. --185.230.100.66 (talk) 06:28, 27 July 2018 (UTC)

The ability to replicate independently of the nucleus is the defining characteristic of Plasmid DNA, while some suggest that the term episome be abandoned or modified to refer to viruses that may be replicated in the nucleus, see Plasmid#Episomes. DroneB (talk) 12:57, 27 July 2018 (UTC)

AA and KSD

Every aldosterone antagonist that I see is also a potassium-sparing diuretic. Are there any aldosterone antagonists that are not potassium-sparing? 209.149.113.5 (talk) 18:46, 27 July 2018 (UTC)

I think by definition no, because that's just literally what happens when you antagonize the aldosterone receptor (unless there's something else going on with the patient's kidneys). To do something else would require significant off-target activity, at which point I suspect it would not be placed in that class of drug. Someguy1221 (talk) 22:34, 27 July 2018 (UTC)

July 28

Hearing: difference in sensitivity to harmonics and intermodulation.

The reproduction of sound through electronic devices inherently involves "non-linear distortion". It has been known for a very long time that distortion occurs in two forms: harmonic (extra tones in harmonic relationship to source fundamentals) and intermodulation (non-harmonic extra tones that are the sum or subtraction of source tones), and that the ear is both more sensitive to, and finds it more objectionable, to the intermodulation form. For example, the motion picture industry devised a specification and test (the SMPTE test) for maximum allowable intermodulation almost as soon as sound movies were devised. Harmonic distortion they weren't much concerned about.

It seems that this extra sensitivity to intermod is inherent in the structure of the inner ear. Almost all natural sounds contain lots of harmonics. Intermod pretty much does not occur in nature. Does anyone know what evolutionary advantage this has conferred, remembering that human evolution is essentially stopped at the caveman era, or perhaps at the stone age era, when there was certainly no high quality electronic sound? Or is it that excess sensitivity to intermod conferred no evolutionary disadvantage? One would think that as harmonics are normal in nature, that that is what we ought to be most sensitive to. 118.209.51.33 (talk) 16:37, 28 July 2018 (UTC)

Evolution hasn’t stopped. There was not a ‘direction of travel’ of evolution to arrive at where we are now, for humans, giraffes, hippopotami, or dinosaurs etc. — Preceding unsigned comment added by 82.38.221.49 (talk) 17:30, 28 July 2018 (UTC)

So? How does that help?118.209.58.85 (talk) 16:24, 29 July 2018 (UTC)

Human hearing ability has ceased to be a parameter for evolutionary selection since our hominid ancestors struggled in a predatory environment. Our hearing sensitivity and frequency range have become inferior to the cats and dogs around us, though we claim to have developed a finer tuned cultural appreciation of sound (music) than they. We also value our hearing directionality, a hangover from the use of hearing in stealthy stalking or predator avoidance, enough to invest in Stereophonic sound reproducers. This direction sensitivity depends on relative signal phases at each ear (compare with Phased array ultrasonics). A reason intermodulation tones are objectionable is that they can only confuse detection of a sound's direction while harmonic distortion of a single tone does not impede hearing where it originates. DroneB (talk) 13:20, 30 July 2018 (UTC)

No. While GROSS intermodulation distortion (several percent of total sound energy) can make perception of direction difficult, the ear can detect intermodulation at far lower levels, and find these levels unpleasant. Electronic engineers has found it necessary to get intermod in sound equipment below 0.1%. OP121.44.191.221 (talk) 02:35, 31 July 2018 (UTC)

In case it's still not clear to the OP, when your conclusion is based on a faulty premise, it could easily be flawed. The idea that human evolution basically stopped at the stone age or the caveman era is not generally accepted as true. (It's true that some evolutionary biologists have made that argument but I wouldn't say it's widely supported [14] and even for those who have made it, I don't think they intended it to be taken the way some e.g. in the paleo movement have done. And obvious reason is it's easy to find examples which show it's untrue e.g. lactose persistence or the various genetic resistance to malaria.) To be fair, I'm not sure if this particular premise matters so much. If you're right that intermodulation distortion basically only really occurs with electronic (or even electric) sound, and not with other forms of human induced sounds, I think few would suggest there has been sufficient evolutionary pressure to result in such a significant shift in how we hear it that it's something that is widely untolerable. However the wider point remains that if you are coming to a conclusion, you need to be sure your premises are correct and lead to those conclusions. Nil Einne (talk) 19:55, 30 July 2018 (UTC)

Evolution in humans has essentially stopped. That is something that is abundantly clear. It is true that some think it hasn't but then some people believe the Earth is flat, and some don't believe in evolution at all, and have got laws in some US states to ban teaching it. And if you think humans have evolved to enjoy electronically reproduced sound (pretty much the only source of intermodulation), then you must be on a substance. But in any case, all this has actually little to do with my question. OP121.44.191.221 (talk) 02:35, 31 July 2018 (UTC)

No credible astronomer or physicist believes the earth is flat. Probably most evolutionary biologists do not accept human evolution stopped in the stone age or cave age, as per my ref. There is a big difference. As for your second point, it has nothing to do with what I actually said since I specifically noted that if intermodulation truly arose with electronic or electric sound, it is unlikely anyone would credibly suggest there was sufficient selective pressure to cause it to have arisen. As for your third point, I already explained why it has to do with your question. If you are unwilling to accept you may be wrong, or think being wrong makes you an idiot, that's your choice, but it means you are unlikely to be able to get any help on the RD. Nil Einne (talk) 05:09, 31 July 2018 (UTC)

If I understand this question, the OP is asking whether the aesthetic appreciation for sound is derived from an evolutionary tendency - and in specific, if there is an evolutionary reason to prefer certain harmonic tones, as opposed to non-harmonic combinations.

The answer should be a clear and sonorous no, this aesthetic preference is not an evolutionary effect; this is a learned, acculturated phenomenon related to the history and culture that has had a dominant effect on the music and sounds that many of our readers are exposed to.

Our article on Tonality is a good starting place; and our ancillary article, Atonality, has this to say: "the term atonality describes music that does not conform to the system of tonal hierarchies that characterized classical European music between the seventeenth and nineteenth centuries..." (with just massive amounts of citations to great music-theory sources all throughout that article).

So: no, we humans did not have any evolutionary or biological reason to prefer harmonic sounds, nor was there any evolutionary reason to dislike nonharmonic sounds (including, but not limited, to the sounds caused specifically by intermodulation of acoustic frequencies). Any such predisposition that you or others may have is a learned behavior that is heavily influenced by your exposure to the musical traditions of renaissance-era Western European societies, and the more subsequent modern music that developed from those cultures.

Nimur (talk) 05:13, 30 July 2018 (UTC)

These are very definitive statements, but I'm not convinced that they are correct. Harmony actually has a very strong and straightforward physical significance. When you have a simple source of sound, it usually produces a base frequency and a set of "harmonics", that is, tones with frequencies that are integer multiples of the base frequency. As the name indicates, the harmonics harmonize with each other. When you have multiple sound sources, the tones that they produce typically do not harmonize with each other. Therefore, harmony is a signal that a sound comes from a single source. Thus, the ability to perceive harmony goes with the ability to distinguish single sound sources from multiple sound sources. I can't prove that that has evolutionary importance, but it does seem plausible to me. Looie496 (talk) 14:44, 30 July 2018 (UTC)

It sounds like the OP is saying we shouldn't really hear or care about intermodulation distortion much because it rarely occurs in nature so it's not something the ear should have evolved sensitivity to. They are therefore wondering if the structure of the inner ear evolved in such a way to cause sensitivity to intermodulation distortion and why it would have done so. Or if alternatively because intermodulation did not occur, there was no reason for us to evolve to have little sensitivity to it but there was for harmonic distortion. Personally I think the OP's question is based on too many faulty assumptions and misunderstandings, but I'm not sure if Nimur's answer really properly addresses them. Nil Einne (talk) 19:55, 30 July 2018 (UTC)

I don't know enough and haven't put in the time to riddle this out, but there is a lot about harmonics in the cochlea, e.g. [15] I would speculate that there may be a difference in how much the two types of distortion affects the final neural signal, but I don't know that. Wnt (talk) 14:36, 30 July 2018 (UTC)

The unpleasantness of IM (intermodulation distortion) is the reason loudspeakers for music are constructed with multiple transducers in the same enclosure, each reproducing only a part of the audible frequency range. Is it feasible, either theoretically or on practice, to remove IM from an old recording by modelling and inverting the signal non-linearity? DroneB (talk) 00:24, 31 July 2018 (UTC)

This is off topic, but you are correct about loudspeakers. It is theoretically possible to remove intermod from old recordings to some extent, but in practice its extremely difficult and usually impossible. There are essentially three reasons why it is extremely difficult:-

Many musical instruments have a tonal structure that is not precisely harmonically related. Snare drums have a large number of frequencies in their sound, but they are NOT harmonically related. Pianos are tuned so that the string relationship is close to harmony, but not exact. Some pianos (eg honky-tonk) are quite well off harmony. The human voice contains overtones that are not harmonically related.

I was once engaged in the design and manufacture of guitar amplifiers. It's one thing you learn in that business, it's that if there is some effect or artifact, some musician somewhere will devise a way to exploit it in a hit tune. For example, fuzz, widely used in rock and to some extent in jazz, is gross distortion. How does some machine identify what's unwanted distortion, and what's not?

The number of additional tones created by intermod rapidly becomes very large as the number of tones in the source sound increases. You would need a warehouse full of supercomputers to figure it out, for any but the acoustically simplest of recordings.

Note that an overtone structure, such as the human voice or a piano, or percussion instruments, is NOT imtermodulation, and doesn't sound like it, but its still additional tones just as intermod is, so is diffult to distinguish mathematically. OP 121.44.191.221 (talk) 03:00, 31 July 2018 (UTC)

I appreciate the time and effort by everyone who responded (except Nil Einne, who works on the basis of "I don't know how to answer this, so lets just say the OP is an idiot". Just what misconceptions have I displayed??), but you are all off track. I'll try and clarify my question: Human hearing is more sensitive to small amounts of intermodulation distortion (something not experienced by humans until the invention of radio and movie sound tracks) than it is to harmonic distortion (also an artificial thing). This seems to be inherent to the structure of the inner ear. Is there a possible evolutionary reason why we ended up with that structure, noting that sensitivity to intermod has little or no benefit in nature? My question has nothing to do with tonality or appreciation of Western music. As the motion picture industry quickly found out 100 years ago, intermod is objectionable at very low amounts, regardless of whether it's voice, music, or sound effects.

Since intermod almost never occurs in nature, I am assuming that the ear's sensitivity to it is an accidental by-product of a solution that was a response to some evolutionary pressure, which must have been prehistoric and most likely goes back to the appearance of early mammals or even earlier. OP121.44.191.221 (talk) 03:24, 31 July 2018 (UTC)

Except I never said you were an idiot. I'm not sure why you believe being wrong makes you an idiot, but that's your own problem. It's clear from all my responses that I'm acknowledging that your understanding of audio physics appears to be significantly greater than mine, so it's even less clear why you believe I would call someone an idiot despite their understanding on one area clearly being greatly superior to mine. Both me an the other IP specifically noted your points on evolution are largely incorrect. I provided a ref demonstrating part of this. I also tried to understand what you were asking, and from what I can tell I understood it better that what Nimur did. I attempted to help you by trying to explain what you were asking since I believed, and from your response I believed correctly, that it had been misunderstood and so Nimur's response wasn't really addressing it. In fact your clarification is very close to what I was already thinking, and what I tried to convey with my response to Nimur and Looie496, My mistake for trying to help. Nil Einne (talk) 05:09, 31 July 2018 (UTC)

Yes, of all the responders, you came closest to understanding what I was asking. You mentioned that I thought that as intermod pretty much does not occur in nature, there cannot have been any direct evolutionary pressure to acquire sensitivity to it. It must have been a by-product of some other pressure. Note that harmonic distortion also is not a natural phenomena - it too is an artifact of electronic sound reproduction. However you stated "the OP's question is based on too many faulty assumptions and misunderstandings." But you did not explain/describe just what those assumptions and misunderstandings were. And you could have just declined to post. So, the inference is clear - you think my question is stupid and does not merit an answer. If you had explained/described what was wrong, that would have helped. Or, to put it more plain - you think I'm an idiot (which might well be the case), but isn't the purpose of this website to help, idiots or whatever?

I wish I had not said evolution in humans had effectively stopped. That actually has no real bearing on the question, except that it is obvious that we cannot have evolved to listen to electronic reproduction, and it has caused people to go off on a tangent (eg the "other IP" you mentioned). The human ear has certainly not changed in that time. In fact its really the old Mark XX Mammalian Pattern Ear, with a good brain attached that can understand advanced speech. OP 121.44.191.221 (talk) 05:32, 31 July 2018 (UTC)

I will not be responding further for reasons I will outline on the RDthis latest IP talk page. Nil Einne (talk) 05:36, 31 July 2018 (UTC)

I was mystified by Nil Einne's mentioning of "IP talk page" until it occurred to me to just click on <talk> after my IP. Click on it and you'll see Nil Einne's got his knickers twisted. Oh well. If someone has a go at answering my question, that's great - I can assure you any genuine help will be appreciated. If not, well, I am unlikely to post any more questions. OP118.209.32.109 (talk) 06:52, 31 July 2018 (UTC)

Red meat and diabetes

Red meat says A 2016 literature review found that for the each additional 50g per day of processed meat (e.g., bacon, ham, hot dogs, sausages) consumed, the risk increased 4% for total prostate cancer, 8% for cancer mortality, 9% for breast cancer, 18% for colorectal cancer, 19% for pancreatic cancer, 13% for stroke, 24% for cardiovascular mortality and 32% for diabetes. The source is [16] ("Free Access"; not sure if that means it's open access or that I can access it due to my on-campus IP address), and most of its references to diabetes are merely comments; the exceptions are Table 1, Figure 2, and Figure 3. [Figure 3 proposes a mechanism whereby various chemicals in red meat trigger insulin resistance.] Am I missing something, or does the author merely give the statistics (with sources, of course) and propose an explanation, or does he give methodology somewhere? Here in the USA, at least, individuals with higher consumption of red meat have disproportionately high rates of general poor eating, including obvious diabetes-associated sugary foods. If the latter, it's still a reasonable thing to state in a research article because it poses a topic for research ("does red meat cause diabetes, or is it associated with something else that causes it?"), but by stating this information where we do in Red meat, we're implying causation, which isn't seemingly appropriate unless the author's reviewing studies with control groups whose diets were similar minus the red meat. Nyttend (talk) 17:06, 28 July 2018 (UTC)

Here's a more rounded source: [17]. 86.131.233.223 (talk) 17:24, 28 July 2018 (UTC)

A more rounded source? That's a news report! I'm seeking something reliable. Nyttend (talk) 19:10, 28 July 2018 (UTC)

These are just correlations that may disappear after appropriate adjustments as already mentioned in the article. Ruslik_Zero 17:40, 28 July 2018 (UTC)

AFAIK, red meat increases bowel and colon cancer from 4-5% to 5-6%, i.e. if one consumes lots of read meant for most of his/her life. Tgeorgescu (talk) 04:17, 29 July 2018 (UTC)

A study I assisted, which resulted in a publication titled "A Prospective Study of Red Meat Consumption and Type 2 Diabetes in Middle-Aged and Elderly Women," found that there is a positive correlation between red meat and/or processed meat intake and type 2 diabetes. IT was limited to a population of about 35k women age 45+. The risk was adjusted for multiple know variables. The ending correlation was very small, but significant. The highest correlated subgroup was bacon followed by hot dogs. 209.149.113.5 (talk) 17:19, 30 July 2018 (UTC)

Link to 209.149.113.5's study. Thank you! Nyttend (talk) 01:23, 31 July 2018 (UTC)

Type-2 diabetes is caused by eating fat. Count Iblis (talk) 19:32, 30 July 2018 (UTC)

See Cherry picking and WP:MEDRS. Your source is crap, and as you always do, you enforce your peculiar singular opinions about nutrition on the reference desk by finding sources of questionable reliability that ex post facto conform to your peculiar, otherwise unsupported beliefs. Lifestyle causes of diabetes mellitus type 2 does not make it out so simple, and unlike the shit source you just posted, does itself reference several well-respected peer-reviewed journals. Yes, fat intake is linked partially to type 2 diabetes, but you, and that article, make a definitive, direct causal link that actual reliable sources don't. There is not a one-to-one correspondence, and correlations between fat intake and the disease in question are only one of the melange of possible causes of the disease. Please just stop, and keep it to yourself from now on. Saying nothing at all is more helpful than spewing crap like this.--Jayron32 02:52, 31 July 2018 (UTC)

I feel a big issue is use of the word "significant" in correlation studies. It doesn't mean "important" or "extensive." It means "cannot be solely attributed to random factors within the confines of our study." So, if I do a study and I find that there is an extremely weak, but "significant," correlation between fat intake and DM, a non-scientific person might think that I am saying fat intake and diabetes have a significant, e.g. important or extensive, relationship. What I'm really saying is that I haven't been able to completely rule out the correlation as random. Sometimes it turns out to make sense. Beta blocker usage and lip cancer have a significant correlation and, currently, doctors advise beta blocker users to apply SPF lip balm or wide-brim hats. Also, Februrary (regardless of the hemisphere) and raised blood pressure have a significant correlation. Why? There is no known reason because the effect is worldwide. So, you can't blame the cold (it is warm in the Southern Hemisphere in February). You can't blame air pressure or humidity, which is different all around the world. You can't blame diet. That month holds no significant worldwide diet change. It is just than when the Earth is in a certain position relative to the Sun, more than half the humans appear to have slightly raised blood pressure. In this case, significant simply means we haven't found a way to rule it out as random (yet). 209.149.113.5 (talk) 12:54, 31 July 2018 (UTC)

(ec) @Jayron32: There's no sense getting too carried away, because the Wikipedia article you link makes the same claim as the one Count Iblis linked ... though it is far more restrained in its wording.

To be sure though, there are also relevant foods with a positive role -- cinnamon and cassia, the most commonly used traditional Chinese drugs for the disease, which at the very least are a useful source of dietary fiber for weight loss, and may have other chemicals of note, apples, whose pectin can reduce sugar spikes in the short term, broccoli which contains glucoraphanin. Also coffee has been reported to reduce the risk of the condition -- though oddly, searching now I see this effect attributed to cafestol, which isn't the compound I thought they said before. Wnt (talk) 12:58, 31 July 2018 (UTC)

Tractor model (Montana 1991)

• 

Which model is this tractor? --Nato-Strichmännchen (talk) 19:09, 28 July 2018 (UTC)

Looks like an older model of the Massey Ferguson 230. It seems definitively from this company.--Doroletho (talk) 12:18, 29 July 2018 (UTC)

July 29

Force in rocketry, possibly for quarks inside proton, anywhere else?

Hi if t is time, p(t) is momentum of a pointlike object with mass, then classical physics says that p(t)=m(t)v(t) where m and v are mass and velocity of the opject, and that the net force F(t) is p’(t) = m(t)v’(t) + m’(t)v(t). In a rocket if the mass loss due to fuel consumption can make m’(t) a large enough negative number, can m’(t)v(t) become almost as great in magnitude though of opposite sign, to m(t)v’(t)? Is it possible to gain great increases in speed with small amounts of force this way? My second question is if quarks inside a proton could experience relativistic increases or decreases in mass so rapid that the contribution to net force of m’(t)v(t) is comparable or even much greater than that of mv’(t)? My 3rd question is that since the charges on quarks would complicate even the classical picture (what with electromagnetic radiation), are there noncharged particles that experience th strong force in the same way quarks do, so that a similar regime of m’v dominating could exist in a simpler way? Thank you Rich (talk) 03:38, 29 July 2018 (UTC)

Well, according to Newton's law F=m*a. So, in order to accelerate a ship of mass m, one needs a force F, there is no way around that except for gravitational slingshots (using planets/moons). If m diminishes, yes, the acceleration would be higher, but there is a limit to it (i.e. when all fuel got burned). With present-day technology it isn't possible to separate the quarks inside of a proton (anyway, not upon a spaceship). Tgeorgescu (talk) 04:13, 29 July 2018 (UTC)

No, F=ma when m’(t)=0.Rich (talk) 05:37, 29 July 2018 (UTC)

if one has to look at the the rocket case as a closed constant mass system that includes the exhaust gases, as i just learned a few seconds ago, how does one deal with a case where mass isnt being lost by or gained by something like fuel consumption, but instead by relativistic mass increase?Rich (talk) 05:50, 29 July 2018 (UTC)

In Newtonian mechanics the change in mass is not part of the force equation. If the mass is changing over time/space that will be included in calculations of impulse and work, but that's it. In the relativistic case, you simply use a corrected force equation, like p = γm₀v, F = dp/dt. Someguy1221 (talk) 07:56, 29 July 2018 (UTC)

In "to accelerate a ship of mass m, one needs a force F, there is no way around that except for gravitational slingshots" there is no 'except'. No force == no acceleration. In a gravitational slingshot gravity is the force accelerating the spaceship. Doroletho (talk) 15:01, 29 July 2018 (UTC)

The chain rule derivative you do looks right. As said above, the first term is F = ma. The other term makes it F = ma + m'v. This extra term distinguishes Newtonian momentum from relativistic momentum. The classic case where this matters is that you can take a particle, put it in an accelerator and keep applying force to it, and after a while v scarcely changes - it's moving near the speed of light. Instead the relativistic mass keeps going up and up. To be sure, relativistic mass, while sensible as ever, is presently out of vogue, and you would be encouraged to do relativistic problems using a different formalism and a different definition of "mass"; hence instead of saying p = mv you say p = γm₀v. But F is still dp/dt, and γm₀ is still relativistic mass. Our article on momentum points at variable-mass system. But you have to watch the assumptions in those problems because mass never just "varies" (apart from the relativistic effects); it always comes or leaves taking its own momentum with it. Wnt (talk) 15:00, 29 July 2018 (UTC)

Sonorescence

The old Chambers Dictionary from 1908 defines sonorescence as the property of emitting sound under intermittent radiant heat or light. I can find this mentioned in some older books, e.g. Rubber World vol. 68 (1923): "In this application hard rubber is particularly valuable owing to the accuracy with which it can be machined and also to its remarkable sonorescent quality." Yet Wikipedia has no entry for sonorescence and I've never heard of this property before. Is it real, or was it an old erroneous belief? Does it have a different name today? Equinox ◑ 16:34, 29 July 2018 (UTC)

According to the latest OED (draft third edition of June 2017) the term is now obsolete, but the definition was: "The production of audible sounds by a substance when it absorbs periodically modulated light (or other electromagnetic radiation); the ability of a substance to do this." The OED also comments: "Now sometimes called the optoacoustic or photoacoustic effect." Dbfirs 16:39, 29 July 2018 (UTC)

Thanks; just made a redirect. Equinox ◑ 16:42, 29 July 2018 (UTC)

You beat me to it! Dbfirs 16:43, 29 July 2018 (UTC)

Different expression levels from same reporter inserted into the same place in the genome

I used homology directed repair to get a cassette expressing a fluorescent protein and (eukaryotic) antibiotic resistance gene in a specific place in the genome of a cell line. The cells were cultured under selective medium but for some reason they all show different levels of expression of the fluorescent protein. Why might that happen? It would be interesting to culture them in a live cell imaging microscope to see if high-fluorescence cells divide into high-fluorescence daughter cells but I'm not going to have the opportunity. The cells in this image are fully confluent because I was about to extract the DNA from them but the variation in expression exists at lower confluence also.

Maybe it's an oversimplification to think they're all the same cells and they actually have developed their own epigenetic deviations which have resulting in the differing expression? They were all resistant to that antibiotic though and the antibiotic was expressed from the same transcript as the fluorescent protein via a 2A sequence. --129.215.47.59 (talk) 18:33, 29 July 2018 (UTC)

This is the expected result for most things. I mean, not necessarily that level of variance between clonal cells, but variance in general. "Stochastic gene expression" is virtually an entire field of study at this point. I would recommend going to your favorite research search engine and search for recent reviews on that topic. The stochasticity can arise from transcription factor abundance/activity/binding, epigenetic marks, transcript stability, or translation rates. Or even protein stability. It's a whole field! Some genes are more prone to this than others, and variance can also be influenced by environmental factors and genetic background. If the cells were recently transfected and not subject to clonal expansion yet, whether the transgene is likely to be identical in each would depend on the method by which you got it in there. Someguy1221 (talk) 02:24, 30 July 2018 (UTC)

This [maybe not -- see below] likely has to do with heterochromatin formation or other epigenetic aspects of the genome. See position-effect variegation as one example, though to be sure I don't know whether you have yours next to heterochromatin. Note though that putting multiple copies of something into the genome will make heterochromatin; it's the body's despamming mechanism. Steve Henikoff put out a lot of the key papers in the area. There are some neat examples - the Pigmented Extraepidermal Tissues mutant reportedly formed five different sublineages with different (internal) pigmentation patterns from a single originating mutant [18] though four were lost during an air conditioner outage. I should also comment that "unstable transgene expression" is typically downward and hence disappointing - it was not that uncommon for lines of transgenic mice to just stop producing the transcript as a new heterochromatin region became established, though modern methods allow for better control over both the position and the number of copies.

Actually looking at your picture though, I realize this might be simpler than my first thought. It is possible that some variable aspect of the plating is influencing the expression -- for example, the cells might be at different points of the cell cycle, or some might be experiencing contact inhibition while others aren't, or many other things. The effects I described above should be somewhat clonal in nature, but it looks like you grew up those cells together, and there's no obvious correlation between neighboring cells. There's a lot of variation, but not variegation. If I saw patches of lower expression it would be more likely to be a DNA-based effect. See if you can synchronize these cells in the cell cycle and look at them at known times and/or with cell cycle markers as controls. Wnt (talk) 14:29, 30 July 2018 (UTC)

• There is of course the far more straightforward explanation that your cultures aren't pure. There could be differential uptake/expression of your contruct in different cells. What cell line is it supposed to be, and have you checked that lately? Cell line contamination is a major issue (and one of the many reasons I only work with primary cells). Fgf10 (talk) 07:06, 31 July 2018 (UTC)

July 30

Is the average unpalatability of the plant kingdom (not counting parts the plant wants eaten) increasing over time?

Some have evolved thorns, needles (i.e. pumpkin stems), itching chemicals, poison etc. to discourage being eaten. Nonetheless this is far from universal. Are the undefended species mostly ones where resources are more effectively used for other things like "more seeds" or are they mostly "herbivore defense mutation hasn't happened yet"? If the latter then it seems plausible that if evolution were allowed to proceed for hundreds of millions of more years without human interference then there should be more biomass with anti-herbivore/omnivore defenses by then. Maybe even a reduction in the amount of far-apart, not that sharp thorns in favor of closer-spaced sharper ones. Sagittarian Milky Way (talk) 19:33, 30 July 2018 (UTC)

Your proposition assumes that plants would evolve while herbivore animals would not; however, "unpalatability" is a moving feast: see Coevolution. {The poster formerly known as 87.81.230.195} 90.217.102.16 (talk) 20:05, 30 July 2018 (UTC)

Is defense getting better then? And offense too of course (poison resistance, tougher mouths etc.) Sagittarian Milky Way (talk) 20:19, 30 July 2018 (UTC)

Err . . . yes, but so is attack. Did you not read Coevolution#Predators and prey? OK, try Evolutionary arms race. All this is Evolution 101. {The poster formerly known as 87.81.230.195} 90.217.102.16 (talk) 22:52, 30 July 2018 (UTC)

If I see 300 million AD and every plant is covered in glass fur I'd still consider defense increased even if it makes no difference in relative terms (the evolutionary arms race). Would be interesting to see what can eat that though. Sagittarian Milky Way (talk) 23:39, 30 July 2018 (UTC)

Herbivory is not the only selection pressure that operates on plants. Plants compete with each other, and other organisms, for access to resources. They also have to withstand attack by fungi and microbes. Defenses against any of these are not free to the plant, and thus plants' phenotypes will change over time based on the balance between different selection pressures. Of course this works the other way around too! You can probably find at a nearby grocery store fruits produced for consumption by animals that no longer exist. They only haven't gone extinct because the plant got lucky and was "adopted" by humans, who can propagate the plant without eating the seeds.

There's not really any objective way to quantify "more" or "less palatable". Thorns might make you less inclined to eat a plant, but they make little difference to giraffes, which have thick tissue covering their palates for consuming thorny plants, or to insects crawling around on the plant. There is no "ultimate goal" evolution is working towards, so saying "herbivore defense mutation hasn't happened yet" doesn't make sense. --47.146.63.87 (talk) 03:58, 31 July 2018 (UTC)

So why don't say maple leaf stems have thorns or noxious chemicals like poison? Has it been tried but other maples were more successful and it never caught on or is it more likely that a thorny maple hasn't existed yet? (("thorn mutation never happened" (in that species)). I've heard THC was invented to be sunscreen. This was useful and cheap enough to catch on (to wild THC percents, not the extreme THC percents of modern breeding of course). But neighboring plants that can't reproduce with cannabis don't have it so it seems like useful mutations can just be too rare to have happened by 2018 AD. If so then it'd stand to reason that there's species that would probably select for THC or poison or thorns or whatever if only that mutation would happen and give it a few hundred million more years of uninterfered with evolution and some of these mutations that'd be selected for but haven't happened yet would happen and spread right? Sagittarian Milky Way (talk) 06:55, 31 July 2018 (UTC)

It takes energy to make thorns or poisonous substances. And there are different protective mechanisms, eg attracting animals like ants that may defend the plant, hard impenetrable bark. Also thorns will not stop small herbivores like caterpillars or beetles. Dumping all the leaves every year also will disrupt the animals that depend on eating them. Some weeds will just grow and flower very fast. Graeme Bartlett (talk) 07:54, 31 July 2018 (UTC)

Chemical elements and the next, nearest one

I'm just completing my knowledge of chemistry and need to ask one last thing:

When an element, say gold, becomes gold, does it become gold from an adjacent element on the periodic table, because it got an extra bit, or lost an extra bit? A yes or no is fine, if you like.

Many thanks,

Anna Frodesiak (talk) 21:28, 30 July 2018 (UTC)

In general, both are possible. For example, through:

• Alpha decay in which the element's atomic number decreases by two (and mass number by four)
• Beta decay in which the element's atomic number increases by one (mass number remains constant).

For gold in particular, see Synthesis of precious metals#Gold. Some rare isotopes of platinum, thallium etc, do decay into gold naturally, too. Abecedare (talk) 21:43, 30 July 2018 (UTC)

Thanks, Abecedare. Ah, so gold can come into existence from thallium without mercury ever being involved, right? Anna Frodesiak (talk) 21:51, 30 July 2018 (UTC)

Yes. For example, ¹⁸¹Tl alpha decays into ¹⁷⁷Au (which itself is unstable and will soon decay into isotopes of platinum or iridium). Abecedare (talk) 22:02, 30 July 2018 (UTC)

Looking at the wonderful chart at [19], which, be warned, is going to simply vomit tremendous amounts of information at you... I see that the one stable isotope of gold, ¹⁹⁷Au, can be arrived at from beta decay of ¹⁹⁷Pt, and electron capture from ¹⁹⁷Hg. There are many unstable isotopes of gold that are themselves parts of other decay chains. As you can see at Isotopes of thallium, a number of thallium isotopes can decay by alpha emission directly into gold, but all of these yield unstable isotopes that then further decay into something else. Someguy1221 (talk) 21:58, 30 July 2018 (UTC)

You two have answered my question indeed. And wow, that link is really quite something. Thank you both. Anna Frodesiak (talk) 22:08, 30 July 2018 (UTC)

Gold atoms are from supernovas. Not every last gold atom of course. Supernovas are hot enough to turn materials no heavier than iron-56 into gold-179 and even uranium-238 I think. They make the centers of stars look like freezers. Sagittarian Milky Way (talk) 23:50, 30 July 2018 (UTC)

In our supernova nucleosynthesis article, there is a chart [20] that shows the origins of each element. It indicates that most gold is produced by neutron star mergers, with a small amount from dying low mass stars. It doesn't appear that any significant amount of gold comes from supernovae. CodeTalker (talk) 00:54, 31 July 2018 (UTC)

Exactly how much of the r-process yield we see comes from supernovae and how much comes from merging neutron stars is still under discussion according to the article; certainly until recently the major site of the r-process was thought to be supernovae. The yield from low-mass stars is from the s-process. Basically, most isotopes of heavy elements can be produced in two ways, both of which involve neutron capture. One way is the s-process (s for slow neutron capture); there a seed nucleus (iron if you like) slowly captures neutrons one at a time. After a few it gets a neutron excess and becomes unstable to beta decay, a neutron converts to a proton, and we have the next element. The other way is the r-process (r for rapid neutron capture), where the seed nuclei are spammed so quickly by neutrons and they have no time to beta decay until the neutron drip line (the point at which a nucleus will not capture and retain another neutron, as its binding energy would be zero). The r-process tends to produce more neutron-rich stable nuclides and the s-process tends to produce the ones closer to the middle (there are also a few proton-rich stable nuclides called p-nuclei whose origin is still a little mysterious), but many nuclides (like gold-197) can be produced both ways. Only for the very heaviest elements (thorium and uranium) does the r-process alone contribute, because the elements between bismuth (83) and thorium (90) are very unstable, and the s-process does not spam neutrons fast enough to cross this gap; that is why thorium and uranium are quite rare in the Universe (qnd what does get produced slowly decays away). Double sharp (talk) 01:33, 31 July 2018 (UTC)

I do not see supernovas in that chart. Anna Frodesiak (talk) 03:54, 31 July 2018 (UTC)

Exploding massive stars are supernovas. Graeme Bartlett (talk) 07:49, 31 July 2018 (UTC)

Ohhhhhhhhhhhh, really?...of course I knew that. :) Anna Frodesiak (talk) 10:27, 31 July 2018 (UTC)

Wikipedia has an article titled supernova that can help you learn more about the subject, especially stuff that you hadn't already known. --Jayron32 15:13, 31 July 2018 (UTC)

How is the optical effect called when you laquer carbon fiber?

How is the effect called when someone laquers carbon. i jknow in wood it means chayotance but i never find anything related to carbon. i can only find depth effect but i think not that this is the right word to use. — Preceding unsigned comment added by Saludacymbals (talk • contribs) 21:32, 30 July 2018 (UTC)

See the article Chatoyancy that describes the reflectance effect in gemstones and treated wood surfaces. Chatoyant carbon fiber is advertised, see video., and has been used in knife handles, see video. DroneB (talk) 23:57, 30 July 2018 (UTC)

July 31

croaking frog stopping

1. Is 'croaking' sound by a single frog possible or is that always in chorus or group? 2. Will that croaking sound stop momentarily when someone crosses closely to a croaking frog? Thanks.

1 dunno 2 yes. At least in Australia. Greglocock (talk) 12:27, 31 July 2018 (UTC)

It will depend on the species, though there is much commonality in the behavior. For example, when I've encountered the American bullfrog, as it is rather large, the number of individuals in a chorus tends to be small, so I've certainly heard one forlorn bullfrog calling without apparent response at first. As that article says, "choruses are dynamic", which is to say, they have to start (and end) somewhere. My experience with frogs going silent is that it seems to be based on line of sight; I've stood just on the far side of a barberry bush and listened to a chorus of wood frogs clucking away, but often frogs will go silent even from 20 or 30 feet distant if they see me. Wnt (talk) 12:46, 31 July 2018 (UTC)

Shark in bleach solution

In this story it refers to the shark being put in a bucket with a bleach solution.

I couldn't work out whether this was supposed to be amateurish/cruel (a bucket that's previously been used for cleaning, filled with water) or clever/pre-planned (a bucket deliberately filled with a liquid a shark would be comfortable with).

I suspect the former (surely bleach harms most creatures?) but am unsciency enough (I refer you to my last use of brackets) to recognise it may be the latter.

Which is it? --Dweller (talk) Become old fashioned! 14:05, 31 July 2018 (UTC)

You've presupposed intent with regard to the bleach solution, which is not evident from the text. An equally likely explanation is that the people who stole the shark grabbed a random bucket, which had previously been used to mop a floor with, and thus contained a bleach solution, threw the shark into it, and attempted to walk out. Nowhere in the article does it state that the couple intentionally used bleach or even knew the bucket contained the bleach. It's always good to make the fewest assumptions possible, and to not explain things which are themselves not established as true first. See Occam's razor. --Jayron32 14:09, 31 July 2018 (UTC)

I thought I had that covered with "amateurish ... a bucket that's previously been used for cleaning, filled with water" but if by including "cruel" (I think stupidity/lack of deliberate malice doesn't necessarily make things not cruel) I didn't make it clear enough, that was indeed one of the two options. --Dweller (talk) Become old fashioned! 14:17, 31 July 2018 (UTC)

Why yes you did. My apologies for not reading your question more carefully. I was rude, and for that I apologize. --Jayron32 15:12, 31 July 2018 (UTC)

And now you were lovely and for that I'm very grateful. :-) --Dweller (talk) Become old fashioned! 15:37, 31 July 2018 (UTC)

Here's a news article from (sort-of-) local news channel NBC 5 Dallas/Ft. Worth: Horn Shark Found After Being Stolen From San Antonio Aquarium, including a lengthy interview video with the local police. Describing the shark's health and condition: "...Luckily, the thief was somebody who knew what he was doing..." according to Leon Valley Police Chief Joseph Salvaggio. The police chief declined to discuss questions that were specifically about the bleach solution.

Here is more coverage from KSAT San Antonio: Shark stolen from San Antonio Aquarium is rescued.... "Spellman (General Manager lf the San Antonio Aquarium) said that the bleach solution the shark was placed in might have shocked the shark's system, which made aquarium staff and authorities uncertain if the shark would survive the heist. But, to the surprise of police and aquarium staff, the shark was in good health when it was returned Monday night."

Nimur (talk) 14:21, 31 July 2018 (UTC)

The CNN version of the story is kind of oddly worded, but I inferred that they had dumped the bleach first.[21] ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:00, 31 July 2018 (UTC)

Great detective work, Bugs. Curious stuff. I love this: "The police chief declined to discuss questions that were specifically about the bleach solution.". I'm going to stick with amateur/unintentionally cruel for now. --Dweller (talk) Become old fashioned! 15:39, 31 July 2018 (UTC)

• There are various kinds of bleach. I think a chlorine bleach such as Clorox is going to be harmful to just about any living thing. However, oxygen bleaches such as OxiClean are relatively nontoxic if the concentration isn't too high, and might even provide some oxygen to the shark. Looie496 (talk) 16:29, 31 July 2018 (UTC)