mtDNA is passed down from females to all of their children; shouldn't there be people around who carry denisovan or neanderthal mtDNA because they had a great- great- (etc) grandmother who was denisovan or neanderthal? | AskScience Blog

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Thursday, August 23, 2018

mtDNA is passed down from females to all of their children; shouldn't there be people around who carry denisovan or neanderthal mtDNA because they had a great- great- (etc) grandmother who was denisovan or neanderthal?

mtDNA is passed down from females to all of their children; shouldn't there be people around who carry denisovan or neanderthal mtDNA because they had a great- great- (etc) grandmother who was denisovan or neanderthal?


mtDNA is passed down from females to all of their children; shouldn't there be people around who carry denisovan or neanderthal mtDNA because they had a great- great- (etc) grandmother who was denisovan or neanderthal?

Posted: 23 Aug 2018 06:12 AM PDT

in 2012, pestalotiopsis microspora was discovered to be able to live entirely on polyurethane. Has anything developed since then for practical application as a biodegrader?

Posted: 22 Aug 2018 09:34 AM PDT

Would it be possible to design a spring with variable stiffness depending on an applied electrical current?

Posted: 23 Aug 2018 06:10 AM PDT

Say I want to design a constant force translational spring with a decent amount of play. For a constant force Fc, I guess the spring would have to obey Hooke's law F = kx, where k would equal to Fc/x.

Are there any materials where one could vary the stiffness using a current, or otherwise achieve a similar result? Current designs for constant force springs seem to have very little play. I could use an actuator but want to keep it as light as possible.

submitted by /u/FadieZ
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Does a large-scale terrain irregularity database exist?

Posted: 23 Aug 2018 06:37 AM PDT

Greetings.

Considering that:

  1. The mountain/non-mountain distinction is subjective;

  2. "Land can have a degree of ruggedness whether or not it is described as a mountain. Moreover, land at low elevations can be more rugged than land at higher elevations."1

I'd like to know whether a database showing the proportion or index of large-scale terrain irregularities - i.e. of tens of miles or more - by country exists. The purpose is to infer the level of difficulty in the laying of infrastructure and to carry out cross-country comparisons.

Ideally the database would allow to restrict the data to land with the exclusion of body of waters such as lakes or rivers.

Thanks.


1 "Consider the analogy of hills. Hills can be of varying degrees of steepness; the steeper the hill, the more exertion required to get to the top. Yet there is never any debate over whether an inclination is a hill. Indeed, public roads often display gradient ratios indicating precisely how steep a hill is: 1:10; 1:8, etc. Such quantifications make calculations of the energy required to traverse the hill possible (or, alternatively, which gear to put your car or bicycle in); a sign reading "Hill" or "Not a Hill" would not."

submitted by /u/In_der_Tat
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If the universe is expanding at an accelerating rate, does that imply that certain parts of the universe are in principle unobservable/unknowable?

Posted: 22 Aug 2018 05:27 PM PDT

Color Blindness in Men?

Posted: 23 Aug 2018 05:45 AM PDT

I read somewhere that color blindness affects men much, much more than it affects women (approx 1/12 men vs 1/200 women). Can anyone explain why that is the case? I'm sure there probably isn't much research in this particular topic, but if anyone has some leads or ideas that'd be great.

submitted by /u/B1toE2
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Discussion in Hawaii: Do the two 14,000 ft. mountains on Hawaii Island, especially massive Mauna Loa, impact the path of approaching hurricanes?

Posted: 22 Aug 2018 04:48 PM PDT

Exerting influence on them so they tend to veer off? Question being much discussed today with Hurricane Lane bearing down.

Speculation is that if a hurricane had a direct path to the Big Island, it would strike and devastate, but if the storm skirts the island to begin with, the mountains might act to amplify movement towards open ocean.

submitted by /u/Markdd8
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If there's a cosmic horizon and we can never go outside it, are we not inside a black hole right now?

Posted: 22 Aug 2018 09:08 PM PDT

I thought of this because I was told in billions of years we would be unable to travel outside our local supercluster due to space expansion. Isn't this the same thing as being inside the event horizon of a black hole where the contents (mass) of the black hole were just the galaxies of our local supercluster?

submitted by /u/TheNarwhaaaaal
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What are the metals the most hazardous to humans?

Posted: 23 Aug 2018 03:24 AM PDT

Which metals in their elemental state would pose the most serious hazard if they enter the body?

Also does metal toxicity get worse as the metal is heavier, or are there other factors?

submitted by /u/88880
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How does an ovary decide which egg to drop?

Posted: 22 Aug 2018 09:38 AM PDT

When the body drops an egg from the ovary in anticipation of being fertilized, how is the specific egg chosen? Is there a queue of eggs waiting in a funnel-like system that switches every other month? Is it completely random?

submitted by /u/upsidetoolkit
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How do IR detection cards work?

Posted: 23 Aug 2018 02:49 AM PDT

I recently saw this vid: https://youtu.be/iR1Ku5dnbH8 . And it showcased an infrared detection card, which seemed like magic to me. How do they work?

submitted by /u/Pauliusvaliuke
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Why is Young's Modulus of metals the same for compression and tension?

Posted: 22 Aug 2018 04:44 PM PDT

I've found numerous sources that say Young's Modulus for most metals is the same for compression and tension. This confuses me because I've also found numerous sources that show that the repulsion forces between atoms increases more sharply with respect to deviations from the undeformed position than do the attraction forces. See this picture. This would imply that Young's Modulus would be greater for compression than tension, since compression deformation would have to overcome more atomic force than tension deformation. Is it because when deformations are small the change in repulsion and attraction forces is approximately symmetrical as shown in this picture from this website?

submitted by /u/bnpm
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Are there North American species that have invaded other countries/continents causing issues or extinctions through human travel like we experience?

Posted: 22 Aug 2018 06:55 PM PDT

For example killer bees, carp, zebra mussel.

submitted by /u/Trumphantsurprise
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What happens to individual solar systems when galaxies collide?

Posted: 22 Aug 2018 06:14 PM PDT

For example, in a few billion years the Milky Way and the Andromeda galaxies are going to collide...what will happen to the our solar system at that point?

submitted by /u/Bradadiah
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Why do I look different on my camera than I do in the mirror? Which is what I most closely look like in person?

Posted: 22 Aug 2018 04:55 PM PDT

So on my selfie camera my face looks a lot redder and you can see pores being pronounced . In the mirror I look much better with my face all clear.

submitted by /u/0288572
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Why does CO2 trap heat in the atmosphere instead of preventing heat from entering the atmosphere?

Posted: 22 Aug 2018 02:02 PM PDT

When an electron and positron collide with each other two gamma rays will be produced and the angle betwenn these two is 180°. Why must the angle be 180°?

Posted: 22 Aug 2018 11:38 AM PDT

What happens if hurricane hits a volcano?

Posted: 22 Aug 2018 11:28 AM PDT

This may be a dumb question, but the current events in Hawaii made me curious.

Thanks for your time.

submitted by /u/SeederLol
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Can an electromagnetic an wave exist only within certain frames of reference?

Posted: 22 Aug 2018 07:10 AM PDT

I was once pointed out this paradox by a physics teacher:


Imagine an isolated Moon with enough gravity, in vacuum to be more "dramatic". There is a pedestrian standing on its surface. At the same time, up there there is a unlucky space-diver who is in free fall towards the same ground the pedestrian is standing. This space-diver is holding an electron between his thumb and his index finger.

Whether inertial or not frames of references, it happens to be that the pedestrian can observe an electromagnetic wave coming out from that electron, because it's an accelerated charge. But at the same time the space-diver can't observe the wave because on his frame the charge has no motion (therefore no acceleration). How happen that the E.M. wave exists in one frame but doesn't exits in the other?


My teacher already told us that this is still an unsolved paradox, and that Maxwell Equations and relativistic electrodynamics still hasn't a clear answer. I had been believing him for a decade, but the question poped-up in my head recently. Was my teacher right?

submitted by /u/Lmuser
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On a cellular level, how does aging manifest itself?

Posted: 22 Aug 2018 10:38 AM PDT

How do 'old' cells compare to 'young' ones?

submitted by /u/gzorro
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Is there an electromagnetic equivalent of a black hole where charged particles would need to travel at the speed of light to escape the electric force exerted on it?

Posted: 22 Aug 2018 05:07 AM PDT

Temperature is related to average KE. Interstellar space is said to have a temperature of 3 degrees K. Does that mean interstellar particles are barely moving?

Posted: 22 Aug 2018 08:25 AM PDT

I understand that a warm thermometer in space would eventually radiate nearly all its energy, finally coming to thermal equilibrium with the surroundings, and display 3 degrees K. But how does this square with the fact that space particles are zipping around at high velocities and high KE (I presume)?

submitted by /u/xaplexus
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