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Monday, April 27, 2020

Is the average human being closer to the size of the entire observable universe or closer to 1 planck lenght?

Is the average human being closer to the size of the entire observable universe or closer to 1 planck lenght?


Is the average human being closer to the size of the entire observable universe or closer to 1 planck lenght?

Posted: 26 Apr 2020 03:27 PM PDT

On a scale that ranges from 1 plank lenght to 93 billion light years where would the average human being fall on that scale? would we fall towards the lower end or the upper end of the scale?

submitted by /u/FauxxeUK
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Do other Great apes pee holding their penises with their hands or is that just humans?

Posted: 27 Apr 2020 08:22 AM PDT

Is Vitamin D the only essential nutrient we can get from something other than food?

Posted: 26 Apr 2020 01:53 PM PDT

Vitamin D we can get from sunlight. Is there any other essential nutrient we get from the sun or other means aside from eating?

submitted by /u/PowerfulBlubie
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What's with the Tapir continental distribution?

Posted: 27 Apr 2020 07:10 AM PDT

I understand there are four species of Tapir, three in South and Central America (the mountain, lowland, and Baird's) and one in Southeast Asia (the Malayan). How did this happen? Do we know on which continent they first evolved?Are they an example of convergent evolution? If not how did a rouge Tapir get to a whole different continent? We're there more widespread populations at one point and these two islands are all that remain? I just want to know how these weirdos got where they are. Thanks!

submitted by /u/Okapi_johnstonii
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What causes weekly trends in Covid19 Death Toll?

Posted: 27 Apr 2020 07:21 AM PDT

Looking at the data of of daily reported deaths, there is a fairly consistent weekly trend, showing a relative drop in reported deaths on Sunday and Monday. I assume this is due to reporting logistics but seems that could be adjusted by the reporter. So, confusing. Is there a better explanation?

submitted by /u/CoosForester
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Why is there more head loss in a smaller radius bend than a larger radius bend?

Posted: 27 Apr 2020 08:40 AM PDT

It makes sense to me that this happens but I can't explain it

submitted by /u/tomc2311
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How old is the arctic's oldest ice?

Posted: 27 Apr 2020 06:06 AM PDT

I read a lot that the arctic's oldest ice is cracking up or already 95% gone. My question is, how old is this ice though? Do we have an upper limit from the last time the arctic was ice free (if it was)? Do scientists get ice cores from greenland or the north pole like they do from antarctica?

Is it stationary or does the ice renew itself, i.e. ice melts and grows in other places so that the ice we see now is not the same as the ice last year/10 years ago/100years ago?

submitted by /u/guery64
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How far does lightning spread in a pond, lake, or the ocean? How far do you have to be away to be safe in a large body of water or small for that matter?

Posted: 26 Apr 2020 12:54 PM PDT

Does water go faster the closer it gets to the drain?

Posted: 27 Apr 2020 08:10 AM PDT

Is testing someone for COVID-19 immediately after exposure effective?

Posted: 27 Apr 2020 07:06 AM PDT

Suppose a healthy person was exposed to the virus, and then tested for it that same day (no signs or symptoms showing, and likely within a few hours, or less, of exposure). Would the test still be as reliable as it would be for a person who was exposed, and has been showing symptoms for 48 hours or more?

submitted by /u/-Skal
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What was the population density of T Rexes?

Posted: 27 Apr 2020 02:58 AM PDT

A question I've always had about them - surely as gigantic apex predators, they would have required a large hunting area to feed themselves, but they also have to be densely populated enough to find other T Rexes and reproduce. Do we know how many T Rexes would have existed across North America, for instance?

submitted by /u/onthedown_low
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Why does THC last so much longer in the human body than most other drugs?

Posted: 27 Apr 2020 12:11 AM PDT

How does electricity heating a filament in a light become photons streaming into my eye?

Posted: 26 Apr 2020 05:10 PM PDT

I started thinking about this last night. After a sleepless night and a significant amount of time trying to figure it out from information on the internet, I'm throwing in the towel and asking: what is the process, from the moment I flip the switch to the time the photons hit the cornea? What particles and forces are involved at what stages? I'm relatively educated for a layperson, but not educated enough to construct the full flow chart: HELP ME GET TO SLEEP TONIGHT!

submitted by /u/Perspicacia_Tick
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Why is precise tracking of satellites difficult?

Posted: 27 Apr 2020 01:47 AM PDT

I was recently surprised to learn that satellite collisions like this one can happen (albeit rarely), and even more surprised that the satellites involved had actually been projected to pass each other at 584 meters. I'd always assumed that the orbit of any object large enough to see at all was known to an extremely high precision, since it would be governed by very simple forces.

I'd like to know which factor is the main bottleneck in our ability to precisely predict the paths of satellites and orbital debris. I can think of a couple of

  • Initial conditions - measuring the object's current velocity and position might be more difficult than I'd assumed.
  • Variable gravity - perhaps the inhomogeneities in Earth's gravitational field are large enought to affect the orbit?
  • Other bodies - do tidal forces from the Moon have an appreciable influence?
  • Drag - I'd always assumed that the atmosphere that high up would be completely negligible, but maybe not?

Are one or more of these responsible? Or is it something else?

submitted by /u/Drubbels
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How do quantum computers work? How do you read or write data in qubits?

Posted: 26 Apr 2020 08:58 AM PDT

I understand the principle behind the working of a quantum computer, but how do they read or write data in qubits? What is the actual mechanism behind it? What actuall happens in the quantum computer?

submitted by /u/noclue_noblue
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Do we build up a tolerance to reward chemicals?

Posted: 27 Apr 2020 05:25 AM PDT

A little while ago I came across this video on youtube describing somthing called "dopamine detox". If you don't want to watch it yourself the basic idea is that by performing highly exciting/rewarding activities (such as video games, netflix, junk food etc.) too often our bodies become desensitized to our natural reward chemical and thus we require higher doses to feel good. A side effect of this is that not indulging in such activities gives us lower dopamine levels than we're used to and thus make it more difficult to focus on less immediately and intensely rewarding activities such as studying, exercising or practicing a musical instrument.

Now to my personal anecdotal evidence. Even before watching this video I had been thinking a lot about my psychological health. More specifically, I believe I "feel less" than I used to. Or rather, it's as if my emotions are dampened. For example, I remember a few years ago when I was 15-16, reading/watching romantic scenes in books and tv series (especially "unexpected first kiss" scenes and similar) would give me these increadible emotional highs. It would feel like an adrenaline explosion in my chest. The first time it happened I remember vividly, and I rode that high for days. Nowadays I'm lucky if a get a small tingle of emotion. It also happens that I have played a lot of computer games since. We're talking thousands of hours.

I considered if I was depressed for a while, since I've read that depression can cause similar symptoms, however I haven't displayed any other depression symptoms like agression or anti-social behavior. Could it be that instead of having too low levels of reward chemicals, my body has acclimatized to too high levels like the video describes, or have I simply "outgrown" these powerful emotions after puberty? Is the video "legit" or mostly based on pseudoscience?

submitted by /u/SidewinderTV
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How did we artificially select fruits to grow without seeds? (such mandarine oranges and oranges)

Posted: 26 Apr 2020 09:16 PM PDT

How does the brain know when it is tired?

Posted: 27 Apr 2020 03:14 AM PDT

I thought it may work the same as with hunger, but I can't imagine how the brain could measure its energy level.

submitted by /u/astronaldus
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Will it ever be possible to create a direct image of an extrasolar planet in the same way we can view, say, Mars or Jupiter?

Posted: 26 Apr 2020 02:11 PM PDT

I know that there has been some amazing images of extrasolar planets, such as those around HR 8799 by the Keck Observatory using motion interpolation. But, is there any possibility of acquiring an image in visual light - so that you could say "It's green" or "It's blue".

Thank you!

submitted by /u/Ach3ron-Attacks
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Is there a reason on why Soviet spacecraft was more rounded in design compared to American polygonal or even cube shaped spacecraft?

Posted: 27 Apr 2020 03:04 AM PDT

If you look at Sputnik, the Luna 1 and 2 programs or Soviet landers and satellites you will notice that they all have spheres and cylinders at the Core of their design while American spacecraft had more visible edges like in the Apollo landers and in other satellites. Was that just an aesthetic choice or were there practical reasons behind these designs? And given that rounded spacecraft can't be seen anymore, does that mean that the polygonal design is better?

submitted by /u/AnonCaptain002
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How does a polariser filter out certain components of unpolarised light?

Posted: 26 Apr 2020 10:59 PM PDT

I understand that a polariser has the ability too let light waves of a specific polarisation pass through. My question is how does it blocks out light of other polarisation's? How does the polariser interact with the the light waves? Thanks

submitted by /u/fx-3650P
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Can blood outside human body generate antibodies when exposed to virus?

Posted: 26 Apr 2020 07:05 PM PDT

Im sure it's a dumb question: Why can't scientists test vaccines on blood samples in test tubes, without jeopardizing the human donor? If not, what other components from the human body do the blood need to create these antibodies? Can these be components be "externalized" or synthesized?

submitted by /u/Avonord
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How the phase velocity of de Broglie wave is greater than the velocity of light in free space?

Posted: 26 Apr 2020 08:47 PM PDT

Sunday, April 26, 2020

If the axial tilt of Uranus (97°) was caused by a giant impact that flipped it on its side, then why do Uranus' moons orbit around its equator at the same tilt (≈97°)? Shouldn't their orbits follow whatever mild axial tilt Uranus had before the hypothetical giant impact?

If the axial tilt of Uranus (97°) was caused by a giant impact that flipped it on its side, then why do Uranus' moons orbit around its equator at the same tilt (≈97°)? Shouldn't their orbits follow whatever mild axial tilt Uranus had before the hypothetical giant impact?


If the axial tilt of Uranus (97°) was caused by a giant impact that flipped it on its side, then why do Uranus' moons orbit around its equator at the same tilt (≈97°)? Shouldn't their orbits follow whatever mild axial tilt Uranus had before the hypothetical giant impact?

Posted: 26 Apr 2020 02:24 AM PDT

So the most accepted explanation for Uranus' sideway axial tilt is that it once had a normal tilt like the other planets bar Venus (0° to 30°) but then a certain massive object collided with it and caused it to tilt sideways.

But by that explanation then shouldn't Uranus' moons be orbiting 0° to 30° (or whatever tilt Uranus had before) rather than over its equator?

Did the moons only start forming after the impact? If they were formed before when Uranus still had a mild axial tilt then it makes no sense for them to orbit exactly over present-day Uranus' equator.

submitted by /u/kaksowohe7
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What happens if you get a vaccine for a disease you already have antibodies for?

Posted: 25 Apr 2020 08:53 PM PDT

With the Covid stuff going around, I'm sure there's some people who gained antibodies without realizing it. Does nothing happen?

submitted by /u/SageOfSong
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Can cats recognize their own meow?

Posted: 25 Apr 2020 03:08 PM PDT

Whenever I play videos with cats meowing, my cat freaks out and runs around looking for the supposed cat, he will even wake up if he's asleep. When I play videos or recordings of him meowing he doesn't react at all. So, is this because he can recognize his own meow and if true, is this normal for all cats?

submitted by /u/illuminatilamp
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How do the researchers studying Covid-19 (and other viruses) “store” it?

Posted: 26 Apr 2020 08:03 AM PDT

May be a dumb or obvious question for many, but I really know nothing about virus research or medicine for that matter. I have read that the virus without a host can stay alive from a few hours to a couple of days. So when these researchers are observing under what conditions the virus thrives or dies, how do they store it and make sure it stays alive indefinitely? Or do they need to get new samples all the time from current hosts?

submitted by /u/StarloManfield
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Spectroscopy Question. Are more stable compounds easier to excite? Reading about UV and how conjugated systems raise the wavelength of a molecule and I'm not sure if I'm missing the point. Is it just that pi and n elections are easier to excite and has no relation to the molecule stability?

Posted: 26 Apr 2020 05:30 AM PDT

What determines the reverse voltages of diodes?

Posted: 26 Apr 2020 06:06 AM PDT

Recently been doing some research on early rectifiers and have learned that almost all common metal oxides will work as a diode, but usually at pretty low backward voltages. The most common were cadmium selenide and copper oxide, but improvised homebrew diodes can apparently be made with ferric oxide or zinc oxide.

The issue with them always seems to be the high forward and low backward voltages, cadmium selenide (AKA "selenium rectifiers" in old radios and amps) is 1V forward and 25V reverse, while zinc oxide is 3V at best and copper oxide is often as low as 1V in reverse. Why is this? I know it's something to do with band gaps but how do those relate to actual voltages?

submitted by /u/D0esANyoneREadTHese
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What determines the intensity of rain?

Posted: 25 Apr 2020 06:55 PM PDT

Sometimes there are white clouds that cause a huge downpour and sometimes there are dark grey clouds that have a sprinkle. Sometimes the rain goes forever at a steady pace all day and sometimes it does a huge downpour in 10 minutes then nothing else. What makes this happen? I have tried googling but can't find it, bit might be looking for the wrong word.

submitted by /u/makesenseofyourworld
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How come we can't throw trash into an active Volcano?

Posted: 26 Apr 2020 04:48 AM PDT

I'm just curious as to why we can't take our landfill trash and put it in a volcano? Wouldn't that get rid of it?

I mean I'm sure there has to be a dire consequence that I'm not aware of because I'm sure that's the reason why it isn't happening.

submitted by /u/Buckfuddr
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Is any active part of the human genome thought to be viral in origin?

Posted: 25 Apr 2020 11:50 AM PDT

Are there any traits that we have that we can thank some ancient viral infection for?

submitted by /u/glibsonoran
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Are strings in string theory just field fluctuations?

Posted: 25 Apr 2020 07:16 PM PDT

So Googling "what are strings made of" is not particularly useful for answering this question; I get everything from "nothing, they're purely mathematical" to "they're the fundamental form of all matter and energy", both of which seem...strictly true while not exactly being useful.

In layman's explanations of current quantum field theories we're told that all particles are fluctuations within omnipresent fields. Quarks, electrons, photons, everything is a localized spike of the corresponding field(s) value. Are strings just constructs within these fields that exist in one or more dimensions? As an example, is a one dimensional string representing an electromagnetic particle just a vibrating pattern within some subsection (since strings have length) of the electromagnetic field?

Put more simply, if I ask "what's doing the vibrating", is the answer "field values in the area defining the string"?

Or is this the wrong way to think about it? Does string theory approach fields completely differently?

submitted by /u/Mezentine
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How exactly does herd immunity work?

Posted: 25 Apr 2020 11:05 AM PDT

I admittedly don't know much about the topic, but I've read that in order for herd immunity to be effective, 83-94% of the population must have become immune to whatever infection. Two questions:

  1. How does one define a population? If we are looking at human beings, for example, if 95% of Canadians were immune but 25% of Mexicans were, would that impact overall herd immunity? Does it depend on how much the groups mix?

  2. Does the size of the herd have any bearing on what percentage must be achieved to maintain immunity? For example, would a herd of 100 individuals need a lower percentage than a herd of 100 million?

submitted by /u/permexhaustedpanda
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Any two orbiting bodies lose energy to gravitational waves, but the moon will recede until the Earth is tidally locked to it; Are binary neutron stars that inspiral and merge tidally locked to each other?

Posted: 25 Apr 2020 03:46 PM PDT

Why cant a ramjet transition to a scramjet?

Posted: 25 Apr 2020 09:13 AM PDT

It feels to me that the only thing preventing this from happening is a variable inlet and combustion chamber design. A ramjet could accelerate to its top speed and the inlet/combustion chamber can change to allow supersonic airflow and combustion through the engine.

Wouldn't it be just a matter of varying the angle of the inlet and combustion chamber's walls?

submitted by /u/thesaintscross
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When you run and get a stitch, what is it and why is it so painful?

Posted: 25 Apr 2020 11:12 AM PDT

What goes on in our body when we have the hiccups?

Posted: 25 Apr 2020 07:12 AM PDT

Also, What causes them, whats their purpose, and if there's any evidence whats the best way to treat them?

submitted by /u/JohnyyBanana
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Are there any unexplored regions on Earth apart from the oceans?

Posted: 24 Apr 2020 10:27 PM PDT

Are there any unexplored regions on earth that could harbor totally different kinds of flora/fauna? If so, could there be any indigenous tribes that we don't know of? Thank you!

I don't know which flair to use, hope this is the correct one

submitted by /u/faucaceres
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Could an orbital resonance similar to that of Naiad and Thalassa exist between three moons instead of just two?

Posted: 25 Apr 2020 10:56 AM PDT

(I don't think this is a hypothetical question, exactly, but if this sub thinks it is I'll gladly take it over to AskScienceDiscussion.)

Neptune's moons Naiad and Thalassa share a seemingly unique orbital resonance. Because Naiad's orbit is titled relative to Thalassa's, as the one laps the other, Naiad appears to pass "above" Thalassa (as seen from Neptune) twice, and then "below" Thalassa twice. This cycle results in a stable orbital resonance despite the two moons' orbits being very, very close together.

Is a similar arrangement with three moons possible? If so, what would it look like?

Thanks in advance!

submitted by /u/LeakyLycanthrope
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Why do we develop immunity to some diseases, like chicken pox, but not to others, like the flu and colds?

Posted: 25 Apr 2020 09:30 AM PDT

Does the size of an object determine how big of a sonic boom it makes?

Posted: 25 Apr 2020 09:19 AM PDT

For example, if a pebble was accelerated to Mach 1, would it produce the same type of boom as a supersonic jet?

submitted by /u/Dragon_Overlord
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Is there a difference in the cells that produce uterine walls?

Posted: 25 Apr 2020 08:59 AM PDT

When women menstruate, the "blood" is mostly tissue, but what kind of tissue and how is it produced? (i.e. what kind of cell produces this tissue?)

submitted by /u/WhaleTryAgainLater
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Saturday, April 25, 2020

When did pee and poo got separated?

When did pee and poo got separated?


When did pee and poo got separated?

Posted: 25 Apr 2020 05:43 AM PDT

Pee and poo come out from different holes to us, but this is not the case for birds!
https://en.wikipedia.org/wiki/Bird#Excretory_system

When did this separation occurred in paleontology?

Which are the first animals to feature a separation of pee vs. poo?

Did the first mammals already feature that?

Can you think of a evolutionary mechanism that made that feature worth it?

submitted by /u/Revoot
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Can a severed muscle be put back together?

Posted: 24 Apr 2020 06:50 PM PDT

It might sound odd, but my brain comes up with weird hypotheticals I desperately want the answers to. I tried to google this, but it didn't give the exact answer I wanted.

If a skeletal muscle is completely severed for some reason, as in it is now two seperate pieces, can those pieces be reattached somehow? If so, would that also work if a piece from the middle was removed and you tried putting the remaining ends together? (Ignoring mobility difficulties from shorter muscle length, I just want to know if it's physically possible).

submitted by /u/Medysus
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Where would be the rainiest places on Saturn's moon Titan? How comparable would (methane) rainfall there be to rain here on Earth?

Posted: 24 Apr 2020 09:44 PM PDT

why is it called magma underground but lava aboveground?

Posted: 24 Apr 2020 08:32 PM PDT

google was confusing ?

submitted by /u/woolvivenus099
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When doing human trials for a vaccine, how do scientists know if it’s working?

Posted: 24 Apr 2020 10:47 AM PDT

I realize that part of the human trials are to ensure that there are no serious or long term side effects.

In terms of ensuring the vaccine prevents people from getting sick, will scientists inject people who haven't yet gotten sick yet and then put them in an environment to get sick and just hope that they don't? Or is it just a case of seeing if their body develops the anti bodies and calling it a day if they do?

submitted by /u/WinnipegDuke
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Can other planets see Earth during the day?

Posted: 24 Apr 2020 05:04 PM PDT

I was looking at other planets last night and was thinking about how they're so bright, that what we see must be 'daytime' on each planet. From the perspective of say mars at night time, would you be able to see earth in the same sort of way? (I'm sure I could've phrased it better)

submitted by /u/nozawaiden
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I'm curious, how do we know about the position of a celestial object millions or billions of light years away ?

Posted: 24 Apr 2020 03:43 PM PDT

How did the casque of the rhinoceros hornbill develop? What advantage would it provide over other species, especially early on in the bird’s evolutionary development.

Posted: 24 Apr 2020 07:35 PM PDT

How has the reduced “background noise” from reduced machinery and transport affected seismology?

Posted: 24 Apr 2020 07:37 AM PDT

My country has reported that seismological devices have shown reduced "noise" during our lockdown and that they are led to believe more and more people are disregarding the stay at home order because it has picked back up.

I'm wondering if measurements made now are more accurate/ precise.

Can we look further into the earths crust or predict volcanic/seismic activity better now that our devices can pick up smaller activity?

Or is this a negligible difference when it comes to making measurements of the earths crust/mantle/core etc?

Are there any cool experiments you think should be carried out whilst we have some peace and quiet?

submitted by /u/MalgrugrousStudent
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Can humans get antibodies from mother milk with antibodies by ingestion, for for example the SARS-CoV-2?

Posted: 24 Apr 2020 09:42 AM PDT

So in the Netherlands now they are studying whether they can use mother milk with the antibodies for the virus for elderly to ingest to then be immune to the virus. However, I know that for piglets and calves that the intestine can only absorb the antibodies from the colostrum for only a few hours, but is this the same in humans or can we still absorb antibodies at later age?

submitted by /u/noorhil
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How do logic gates actually 'decide' on it's output based on its input?

Posted: 24 Apr 2020 10:51 AM PDT

Does it work like an election switch or something mechanical? And how are they engineered to the given output when they are so small? The logic gates are so small and I'm not sure how logic gates work physically. I understand the theory behind it but practically speaking? Thanks

submitted by /u/The--World
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How are doctors able to open up arteries and clear them out without tons of blood coming out?

Posted: 24 Apr 2020 04:16 AM PDT