Wikipedia:Reference desk/Archives/Science/2018 June 14

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June 14

Height above ground + distance South from Arctic Circle = Midnight Sun

Mt Denali, the highest peak in the U.S above 20000 ft above sea level and about 18000 ft tall, is 158 straight miles from Fairbanks, Alaska according to a Google search, but it can been seen from some parts of the city. That is key. Fairbanks according to our article about the city is 140 miles South of the Arctic Circle. According to our article, the sun’s disk is above the horizon for 21 hours and 49 minutes at the summer solstice. Therefore, Fairbanks doesn’t experience the midnight sun, but a short “white night” each day during this period. Height above the ground does affect daylight lenghth due to the curvature of the Earth and there are many examples. Given all these facts, let’s suppose that Mt Denali was right next to Fairbanks at the same latitude, 140 miles South of the Arctic Circle, and given that one can deduce that the visibility on a clear day would extend slightly beyond the Arctic Circle when looking North at the top of the summit if Mt Denali were to be at the same latitude as Fairbanks, would the summit get 1 to several days of the midnight sun around summer solstice, but of course not 1 to several days of polar night around winter solstice? Willminator (talk) 05:38, 14 June 2018 (UTC)

Doesn't the Continental Divide go north of Fairbanks? Mountains might block the Sun. What counts as sunset is kind of fuzzy though, pretending that stuff over sea level is air and everything below is water is often done even if your entire horizon is Lake Titicaca and you're treading water almost up to your eyeballs. Pretending you're levitating at Lake Titicaca altitude and surrounded by a sea level horizon with a lot of "distance from Earth"-induced horizon dip makes sunset times there a lot more inaccurate than just assuming the horizon's at lake elevation obviously. And even the Appalachian Range only 2km high can shield enough atmosphere from direct sunlight to make twilight noticeably darker than if that range didn't exist and it was all sea level like the simplified model so why not count mountains as being able to cause sunset? That'd cause a problem of what's the smallest thing that can cause night is though. Is it nighttime if a skyscraper hides the Sun at high noon?, or even your hand? Obviously not so where's the cutoff? Ignoring topography, Fairbanks is close enough to the Arctic Circle to cause midnight sun at Denali's elevation at the city center but ignoring topography though (sea level virtual horizon) Sagittarian Milky Way (talk) 07:04, 14 June 2018 (UTC)

Can "genetically identical" populations belong to different species?

Hello. In "Integrative Taxonomy Resolves Three New Cryptic Species of Small southern African Horseshoe Bats (Rhinolophus)", Taylor et al. admit that their study population of Rhinolophus is "genetically identical" to the existing species R. simulator, but they go ahead and recognise it as a distinct species anyway "on morphological and acoustic grounds". Is this reasoning scientifically solid? If so, why is it not applied to the numerous other species that display clear intra-specific variation, such as Canis lupus? It does seem odd to separate genetically identical populations into different species. Thanks.--Leptictidium (mt) 08:59, 14 June 2018 (UTC)

Genetically identical insofar as they sequenced, which was to a very limited extent. The paper in question, here, only obtained a partial sequence for a single mitochondrial gene, and took limited DNA sequencing from prior publications to use in their analysis. Their hypothesis is that possibly a small portion of the genome, mitochondrial and/or nuclear, is identical between different species due to rare and/or historical introgression events. But one would still expect the great bulk of the genomes to show long-term divergence from one another. That data has not been generated yet. Someguy1221 (talk) 10:25, 14 June 2018 (UTC)

Right. There is no such thing as populations that are fully genetically identical. Even the cells within a single individual body are not fully genetically identical. Looie496 (talk) 17:54, 14 June 2018 (UTC)

It may be possible to have genetically identical species produced via infectious speciation. (Wolbachia being the known example) [1] Biology never stops getting weirder. ;) Wnt (talk) 21:51, 15 June 2018 (UTC)

Human genetics

Can someone help me solve this problem?

In population that is in equilibrium there are four times as more dominant alleles than recessive ones. What is the frequency of the dominant trait in that population?

p² + 2pq + q²

p + q = 1

p = 4q

q = 1/5p

q = .2

p = .8

.2² = .04

1 - .04 = .96

Vs⁶₅⁰⁷ 13:00, 14 June 2018 (UTC)

It looks like you have some chaff there, but note that allele frequency is based on how many alleles are present, and you just said that, i.e. it's p. Usually it's slightly harder to figure out because you have to infer it from the phenotype rather than just being handed the information. Wnt (talk) 13:36, 14 June 2018 (UTC)

It's not about allele frequency, but rather phenotype frequency. So I guess I did correct there... Vs⁶₅⁰⁷ 14:48, 14 June 2018 (UTC)

Oooops, I misread that. Yeah, the dominant trait frequency is 1-0.2*0.2 as you say (at least, assuming the recessive isn't lethal balanced by some advantage for the heterozygote or something similarly wacky) Wnt (talk) 22:29, 14 June 2018 (UTC)

Plugging home appliances in the EU and the US

It seems to me that EU plugs allow the user to plug in a devices in two ways, but the US plugs only allow one way of plugging a device. The same discrepancy applies to other plug types, from other places. They are just examples. Why are they different? --Doroletho (talk) 16:48, 14 June 2018 (UTC)

Our AC power plugs and sockets article talks about all the different countries' standards. For example, a a non-reversible connection where one wire is hot and the other neutral guarantees to the device which is which. That can be a safety feature, for example, to reduce the likelihood that someone will touch something that is connected to the hot or how much of the device remains energized when a switch is "off". It wasn't that long ago that US also had reversible plugs and non-polarized outlets. DMacks (talk) 17:26, 14 June 2018 (UTC)

There a multiple standard of mains plugs in the EU, some of which are polarized, and some not. LongHairedFop (talk) 13:41, 16 June 2018 (UTC)

How do researchers make animals neglectful of their offspring?

I have heard of research experiments in which researchers compare caring animal parents and neglectful animal parents. My question is, how did the researchers manipulate this? Is it some sort of gene that they knock out? Do they train animals to behave a certain way? SSS (talk) 19:31, 14 June 2018 (UTC)

There are always some animals that neglect their offspring. Ruslik_Zero 20:10, 14 June 2018 (UTC)

In some species (including rodents and sheep) animals will neglect their offspring if they don't smell right. Looie496 (talk) 22:09, 14 June 2018 (UTC)

Treatment of mothers with naloxone or genetic mutations that block pheromone receptors will do it. [2] Wnt (talk) 22:31, 14 June 2018 (UTC)

Simply separating the parents from the offspring seems like the simplest way to ensure parental neglect. CodeTalker (talk) 23:26, 14 June 2018 (UTC)

Identify unknown mushroom species

I would like some help identifying these species. These first two photos are of a mushroom that is very similar to a garden-variety mushroom but it is definitely not the edible kind. I found it growing on tbe U.S. Courthouse lawn, and it is really quite toxic. It has a strong earthy or musty odor with something faintly pungent and acrid to it, which immediately caused my eyes to dilate and my stomach to cramp up, and I almost passed unconscious that afternoon and I woke up in the middle of the night with chills and leg cramps. That's just the smell. I really wouldn't eat it. My eyelid is still twitching with an odd tic from that and I heard the neighbor's dog went blind sniffing this kind of mushroom.

The mushroom below looks like some kind of morel to me. I'm not really sure, but it has an overpowering foul odor to it. It was growing on a street corner downtown.

I'm suspecting the spores are spread by the sorry girls and frat boys at University of Alaska Fairbanks who frequent the aforementioned courthouse demanding a total gun ban certiorari in case one of the sorry girls has to dump her boyfriend and all the sisters need a campus police escort to make it safely back to their dorm rooms after their mental health counseling appointments. Any positive I.D.? Need more info. justinacolmena (talk) 20:55, 14 June 2018 (UTC)

It could be Agaricus_xanthodermus which looks like a very large Champignon and smells of phenol. The last picture can be the same when young and by dry weather but I think more for example of some Tricholoma or Lepista. Morel is completely different.194.174.76.21 (talk) 14:42, 15 June 2018 (UTC) Marco Pagliero Berlin

No yellow. No phenol smell. Head is thicker and rounder. Absolutely no one is going to eat this mushroom without ill effects. The last one is not the same as the others. It has a completely different smell. Tricholoma or Lepista are too flat-headed. The shape of this one is pointy-headed like the morel, but it has a droopy, rain-split cap which the morel lacks. False morel? Probably not even. justinacolmena (talk) 18:50, 16 June 2018 (UTC)

But if you're eating unidentified mushrooms, you really should reconsider your priorities. --jpgordon^{𝄢𝄆 𝄐𝄇} 17:26, 15 June 2018 (UTC)

Excuse me. You must have been high on drugs if you thought I was "eating" this mushroom and still alive today. justinacolmena (talk) 18:50, 16 June 2018 (UTC)