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Wednesday, April 17, 2019

What usually happens to refugee camps in the long run? How do they end?

What usually happens to refugee camps in the long run? How do they end?

What usually happens to refugee camps in the long run? How do they end?

Posted: 17 Apr 2019 12:26 AM PDT

After major disasters and wars, the news talks about how international organizations are rushing to set up refugee camps. But you never hear about what happens to those refugee camps in the long run.

Sure, some of them stay around for generations, but is that typical? How long does the average camp stay in operation? What fraction are still active two years, five years, ten years down the line? How do they typically disappear -- do most of their people return home? Do the people move to other permanent settlements? Does the refugee camp gradually become a permanent town? Do the NGOs eventually call it quits and shut down the camps so they can focus on other priorities?

There's lots of individual stories out there, but I'm looking for hard data and statistics on the long-term fate of refugee camps worldwide.

submitted by /u/agate_
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Optics) Why does the cladding's refractive index need to be lower than the core's for TIR?

Posted: 17 Apr 2019 04:48 AM PDT

I understand that this is how it works, but I can't intuitively understand why. In my head it makes more sense for the cladding material to be denser, hence having a higher refrative index for more light to reflect at the core-cladding interface. Would just like some clarification on understanding this.

submitted by /u/WotAmIEven
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Will we be able to synthesize any more new elements? What about a whole new “line” of elements?

Posted: 16 Apr 2019 04:01 PM PDT

I am aware that the scientific community has acknowledged the elements Nihonium, Flerovium, Moscovium, Livermorium, Tennessine, and Oganesson. We have officially "filled out" the last "line" of our periodic table. The man-made isotopes of these elements famously last for milliseconds. So, my question is, is it theoretically possible to synthesize another Alkali metal? Is it theoretically possible to synthesize an entire new line of elements? Also, is it practically possible, as in with our technology now or in the near future will we ever be able to synthesize a new element? Thank you for your time in helping a layman understand chemistry!

submitted by /u/Daniel_RM
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In quantum physics, how can you check a photon is in superposition without taking a measurement?

Posted: 16 Apr 2019 09:38 PM PDT

Reading this article about a quantum experiment, the author states the following:

Wigner's original thought experiment is straightforward in principle. It begins with a single polarized photon that, when measured, can have either a horizontal polarization or a vertical polarization. But before the measurement, according to the laws of quantum mechanics, the photon exists in both polarization states at the same time—a so-called superposition.

Wigner imagined a friend in a different lab measuring the state of this photon and storing the result, while Wigner observed from afar. Wigner has no information about his friend's measurement and so is forced to assume that the photon and the measurement of it are in a superposition of all possible outcomes of the experiment.

Wigner can even perform an experiment to determine whether this superposition exists or not. This is a kind of interference experiment showing that the photon and the measurement are indeed in a superposition.

How can you check for superposition without taking a measurement?

submitted by /u/bot_bot_bot
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Is it possible to create "Anti-Atoms" with Antimatter ?

Posted: 17 Apr 2019 02:25 AM PDT

So I know that antimatter consists of positrones and anti-protons wich are basically the same as

protons and electrons just with opposite charges. So i wondered if there is a possibility that these two can form an "anti-hidrogen atom" and if so if they can form bonds and create "anti-H2" and other molecules (Im not aware of an anti-neutron, so I think that we cannot create more heavy atoms). I know it would be useless because matter and anti-matter annihilate each other but it is interesting if an "anti chemistry" would exist

submitted by /u/whyforgodssakewhy
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What does "1 extra case of cancer per 50,000 lifetimes" mean?

Posted: 17 Apr 2019 06:37 AM PDT

In this article, the author says in the 2nd last paragraph

A team of Swiss researchers calculated that the amount of agaritine the typical mushroom eater is exposed to over the course of their lifetime could potentially lead to 1 extra case of cancer per 50,000 lifetimes. In other words, if it's a carcinogen, it's a pretty weak one. And it's also delivered with an array of cancer preventive compounds, something this analysis didn't try to account for.

My first thought was this means obviously 1 extra case in 50,000 lives.

But then I got confused by the phrasing and was wondering if it means 1 extra case in all the people that live in 50,000 lifetimes (~50,000*80 yrs)

My first, obvious, thought was right, right?

submitted by /u/ThisIsMeRightThere
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Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology

Posted: 17 Apr 2019 08:14 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Biology, Chemistry, Neuroscience, Medicine, Psychology

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

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How is the temperature of exoplanets determined?

Posted: 16 Apr 2019 09:11 PM PDT

Like Kepler-62f is 208 K/-65 °C/-85 °F, but it's still called habitable, even though being out in those temperatures, even in Antarctic winter gear would give you minutes, at most, before hypothermia. I take it there is also some sort of margin of error with the calculation?

submitted by /u/The_Trekspert
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Why is it difficult to unscrew a tight lugnut? I understand why its difficult to make it tighter, because there's something in the way, but why is going backwards also difficult?

Posted: 16 Apr 2019 11:13 AM PDT

I feel like I'm missing something. There is nothing behind a lugnut keeping it from coming off. So what are the physics at play? I asked myself this while working on my car's tires and struggling to get the lugnuts off.

submitted by /u/zakkara
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If a blind individual was aboard the ISS, would they still see the flashes due to interstellar radiation astronauts claim to see when they close their eyes?

Posted: 16 Apr 2019 09:02 AM PDT

How do organ transplants work?

Posted: 16 Apr 2019 02:55 PM PDT

If you are given an organ from someone else's body, the organ is made of their cells and DNA. Wouldn't this cause your body to reject the organ?

submitted by /u/so-gold
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what is the difference between a rock and a crystal?

Posted: 16 Apr 2019 02:39 PM PDT

What happened to the tons of lead in Notre Dame's roof, will it be a health hazard to firefighters or the river in the future?

Posted: 16 Apr 2019 08:39 AM PDT

How would evenly circulated blood, as opposed to the normal pulse, affect the human body?

Posted: 16 Apr 2019 12:09 PM PDT

I remember, at one point, reading about how some people have their hearts replaced with pumps that pump blood continuously, as opposed to the normal pulse of a human. Since we are born and live our entire lives with the beating of a pulse as opposed to an even flow, would that change by itself affect our body in any way?

submitted by /u/ShadowX433
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Why is the surface temperature on Venus hotter than Mercury?

Posted: 16 Apr 2019 08:41 PM PDT

What is the difference between induced pluripotent stem cells and embryonic stem cells?

Posted: 16 Apr 2019 11:23 AM PDT

Hi,

I am curious, what is the difference between induced pluripotent stem cells and embryonic stem cells?

I know about and what stem cells are, but I am wondering if it is possible to generate an embryo from induced pluripotent stem cells. Effectively my interest is, can one induce pluripotent stem cells and then differentiate these into an embryo?

Thanks

submitted by /u/bangbangIshotmyself
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How is the mass of a star determined?

Posted: 16 Apr 2019 09:53 AM PDT

Why is urine yellow and how is it that certain foods/diets can alter it's color?

Posted: 16 Apr 2019 01:33 PM PDT

How do preverbal babies think?

Posted: 16 Apr 2019 08:54 AM PDT
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Tuesday, April 16, 2019

How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place?

How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place?

How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place?

Posted: 16 Apr 2019 02:35 AM PDT

AskScience AMA Series: We're Nick Magliocca and Kendra McSweeney and our computer model shows how the War on Drugs spreads and strengthens drug trafficking networks in Central America, Ask Us Anything!

Posted: 16 Apr 2019 04:00 AM PDT

Our findings published on April 1, 2019, in the Proceedings of the National Academy of Sciences demonstrate that cocaine trafficking, or 'narco-trafficking, through Central America to the United States is as widespread and difficult to eradicate as it is because of interdiction, and increased interdiction will continue to spread narco-traffickers to new areas in their pursuit of moving drugs north.

We developed a simulation model, called NarcoLogic, that found the result of the 'cat-and-mouse' game of narco-trafficking and counterdrug interdiction strategies is a larger geographic area for trafficking with little success in stopping the drug from reaching the United States. In reality, narco-traffickers respond to interdiction by adpating their routes and modes of transit, adjusting their networks to exploit new locations. The space drug traffickers use, known as the 'transit zone', has spread from roughly 2 million square miles in 1996 to 7 million square miles in 2017. As a result, efforts by the United States to curtail illegal narcotics from getting into the country by smuggling routes through Central America over the past decades have been costly and ineffective.

The model provides a unique virtual laboratory for exploring alternative interdiction strategies and scenarios to understand the unintended consequences over space and time.

Our paper describes the model, its performance against historically observed data, and important implications for U.S. drug policy: https://www.pnas.org/content/early/2019/03/26/1812459116.

Between the two of us, we'll be available between 1:30 - 3:30 pm ET (17:30-19:30 UT). Ask us anything!

submitted by /u/AskScienceModerator
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Are 2FA codes random or is there an algorithm in place to make the digits more human-friendly?

Posted: 16 Apr 2019 12:32 AM PDT

Hey,

At my work, as in most tech companies, we use the security tokens to log into certain systems as a 2-FA.

For those who don't know, it's a little device that displays a 6-digit code that changes every 30 seconds and you use it to log into work-related systems. Some sites use your phone for this, steam for example. Others use google authenticator that also has 6 digits.

​

My question is since these codes need to be input manually, are they more human-friendly or indeed, completely random?

I have noticed on the security token I use for work, since I use it way more often than any other 2FA, that often the code is somewhat easy to remember. Often you get codes like "556 789" or "222 001". Digits repeat, follow one another (478), are close on the keyboard (369) or "skip" (727 545).

​

Is it normal practice to incorporate some kind of algorithm into these code generators to make it easier for humans to copy them or are they completely random and my confirmation bias is only remembering the "good" combinations?

​

Thanks.

submitted by /u/Johnny_the_Goat
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Why can we determine the lifetime of short-living particles up to femtoseconds and less, but for the neutron we are unsure on the order of seconds?

Posted: 16 Apr 2019 05:27 AM PDT

I just read this article, and in the last paragraph it says

And the team is already designing its next-generation experiment, which aims to nail the neutron lifetime within 0.3 seconds.

Compared to the lifetime of the Higgs, which is on the order of 10e-22s, this is a pretty large error. How come there is such a huge difference? Do our measurements scale like that? Or is it something like when measuring something like the length of a car we make a bigger error than when doing scattering experiments with nuclear particles?

submitted by /u/Ernst37
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Have there been any recorded instances of stars that have disappeared suddenly (stopped emmiting light)?

Posted: 16 Apr 2019 07:44 AM PDT

I know that GPS systems have a resolution of a few meters. Is there any way to bring this resolution down to the cm? Any available commercial solution?

Posted: 16 Apr 2019 03:42 AM PDT

Maybe an algorithm that takes different measurements and makes another estimation can improve the system.

submitted by /u/ricarvid1
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How and why do bruises form?

Posted: 16 Apr 2019 03:32 AM PDT

How do you predict electronic configurations and bond orders given a molecular orbital (MO) energy diagram (for diatomic molecules only)?

Posted: 16 Apr 2019 01:24 AM PDT

What conditions determine whether a dying star collapses into a neutron star or a black hole?

Posted: 16 Apr 2019 06:45 AM PDT

How do some fish survive so deep underwater? Wouldn’t they get crushed by the pressure?

Posted: 15 Apr 2019 04:39 PM PDT

What is at the center of the Milky Way galaxy?

Posted: 15 Apr 2019 06:13 PM PDT

Whay can't electric vehicles just swap batteries instead of charging?

Posted: 15 Apr 2019 03:58 PM PDT

Are there any limitations to using a battery swapping machine instead of charging station?

submitted by /u/LEOH4Y
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Are tropical storms more frequent and powerful now then they were 50 or 100 years ago?

Posted: 15 Apr 2019 03:08 PM PDT

How have the predictions of climate scientists done so far? What were the predictions? What is the most reliable data?

submitted by /u/ltdata
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Have we lost the ability to see any constellations due to light pollution?

Posted: 15 Apr 2019 04:44 PM PDT

How do you calculate the radius of an atom that isn’t in a bond?

Posted: 15 Apr 2019 03:21 PM PDT

How did the glaciers from the last ice age push sediment south?

Posted: 15 Apr 2019 04:08 PM PDT

If we can use fusion inhibitors to treat HIV, why can we not design other antiviral drugs to target virus-cell fusion?

Posted: 15 Apr 2019 07:11 PM PDT

When antivirals block cell receptors does this cause problems for the cell?

submitted by /u/Pretty_Scientist
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Does putting an aperture in a laser beam make the smallest point it can be focused to larger or smaller?

Posted: 15 Apr 2019 04:40 PM PDT

If you put an aperture in a laser beam to block some of it, I would imagine that the spot it can be focused to becomes larger due to diffraction. The numerical aperture of the system is limited by that truncation of the beam. For a regular laser focusing without an aperture, the beam diameter determines the numerical aperture, not the lens diameter.

But if the spot becomes an infinitesimal pinhole, then it's the same as a point source emitting light. And the equation for how well resolved that point can be is defined by the airy disk using the aperture size of the lens diameter.

So as the aperture is shrunk down, do the two relationships describe different things? For example, does the NA associated with the aperture of the laser beam describe how small of a Gaussian spot can be formed, and the NA associated with the lens itself describe the size of the airy disk that all the light coming through the aperture can be condensed into?

I guess fundamentally it's just confusing because a coherent beam is usually implied to only have a NA related to the beam diameter, but after passing through an aperture it diffracts so the whole diameter of the lens is relevant in picking up and focusing the higher diffraction orders.

Or perhaps my understanding is totally messed up?

submitted by /u/sikyon
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How does the Unix time counter in computers know when a second has passed?

Posted: 15 Apr 2019 12:37 PM PDT

If computers use the unix counter to keep track of time, what does IT use to know when to tick up?

submitted by /u/ZoofusCos
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Monday, April 15, 2019

Why are microwave ovens made of metal but we can't put metal in them?

Why are microwave ovens made of metal but we can't put metal in them?

Why are microwave ovens made of metal but we can't put metal in them?

Posted: 15 Apr 2019 03:15 AM PDT

Do animals have dopamine and serotonin?

Posted: 15 Apr 2019 05:12 AM PDT

Why can every carnivore ear meat raw but humans need to cook it first?

Posted: 15 Apr 2019 04:00 AM PDT

How massive can something get before collapsing into a spheroid?

Posted: 15 Apr 2019 03:29 AM PDT

How is altitude measured on other planets if they don't have seas and hence they don't have a mean sea level?

Posted: 14 Apr 2019 08:59 PM PDT

Why does a plucked string mainly vibrate at the fundamental frequency?

Posted: 15 Apr 2019 04:03 AM PDT

I understand that when a string that is fixed at both ends is plucked, stationary waves can be formed at wavelengths where the frequency is an integer multiple of the fundamental frequency, which is the lowest possible frequency that the string can vibrate at.

Why does a string mainly vibrate mostly at the fundamental frequency, whilst the vibrations due to successive harmonics have less of an effect? What is the reason why vibrating at the lowest possible frequency is more preferable?

submitted by /u/LimeCub
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How do we know for sure that there is molten lava in earth’s core?

Posted: 15 Apr 2019 05:03 AM PDT

Why are some orbital resonances stabilize the bodies in them, but some are inherently unstable?

Posted: 15 Apr 2019 03:23 AM PDT

With the 1:2:4 resonance of the Galilean moons, and 2:3 Neptune/Pluto resonance, you see that their resonance keeps their orbits stable. However with the Kirkwood Gaps you see that a resonance with Jupiter has a destabilizing effect.

What determines whether a resonance stabilizes or destabilizes a system?

submitted by /u/SilentHunter7
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If Adrenaline increases blood sugar levels, but inhibits Insulin secretion, how does the sugar that it promotes get inside muscle cells?

Posted: 15 Apr 2019 04:44 AM PDT

Adrenaline suppresses insulin secretion, which in turn promotes secretion of glucagon. Adrenaline and Glucagon signal the liver to begin breaking down glycogen and secreting sugar, which raises blood glucose levels.

But if Insulin secretion has been blocked, how does this glucose get into the muscles? Or is the glucose meant more for the brain which doesn't require insulin for glucose to enter the cells?

Also, how does nicotine play into this? Myself and a few people who have not smoked for many years, but continued nicotine consumption via vaping, have noticed that the worse thing we can do is vape immediately after a meal. If we vape after a meal, we feel that extreme sugar crash fatigue. However, nicotine tends to be more uplifting when we haven't eaten for many hours. I'm certain this is connected, as Nicotine definitely promotes adrenaline secretion, which in turn suppresses insulin, and raises blood glucose levels.

See: https://bpspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1476-5381.1966.tb01828.x

submitted by /u/Special_Pangolin
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How are Recommended Daily Amounts of micro & macro-nutrients determined?

Posted: 15 Apr 2019 04:46 AM PDT

I know it's obviously only recommended but everyone is so different.

It also leads me to ask do they vary in different parts of the world?

If yes, is this due to differences in what people need in different parts of the world or are the recommendations just calculated/determined differently by different bodies?

If no, should they?

submitted by /u/MartiniLang
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Cleaning Products that kill 99.9% of germs: are these not simply leaving the strongest 0.1% to survive and repopulate?

Posted: 15 Apr 2019 02:30 AM PDT

We see this in antibiotics (MRSA followed Methicillin by ~5 years, I read). Why does something similar not seem to happen in our households/environment? And if it does happen, are we not better off using soap and water, or just bleach?

submitted by /u/darcys_beard
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How does silver nitrate work on wounds?

Posted: 15 Apr 2019 05:05 AM PDT

Silver nitrate is often used in the cautery of wounds in medicine. How does it do that? Is this a redox reaction? Is it exothermic? How does it work? What's the chemical reaction involved?

submitted by /u/ZEPHYRight
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Is there an object that floats on moving water but sinks otherwhise?

Posted: 15 Apr 2019 06:24 AM PDT

What is the Terahertz Gap and why does it exist?

Posted: 14 Apr 2019 07:28 PM PDT

"It is defined as 0.1 to 10 THz (wavelengths of 3 mm to 30 µm)"

I gather we can do stuff below 0.1 THz and stuff above 10 THz, so what is it about this range that creates a problem?

submitted by /u/The_Trekspert
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Does the gravity of the moon have noticeable effects on the planet besides ocean tides?

Posted: 14 Apr 2019 03:00 PM PDT

What happen if an astronaut becomes really ill on the ISS?

Posted: 14 Apr 2019 08:58 PM PDT

Black holes are alway illustrated with their accretion disks around their equators. Is this necessarily the case?

Posted: 14 Apr 2019 02:12 PM PDT

I know there have been a lot of black hole questions lately but now the megathreads are gone, I have another one!

Here is a typical black hole render: https://i.imgur.com/GD9oIBw.jpg

Like most renderings we see the accretion disk in a neatish ring and the energetic jets shooting out perpendicular to it. For a rotating black hole, is the accretion disk always around the equator, and the jets always emanating from the poles?

I know that in Newtonian celestial mechanics, rings are a lower energy and more stable configuration than a spherical shell, which is why you end up with planetary rings rather than spherical shells, but in planet formation scenarios I had thought the only reason these rings (and Moons) tend to be at or near the equator of the planet is because of angular momentum preserved from the original dust cloud that formed the system (correct me if I'm wrong on this!).

Presuming that matter can approach a black hole from nearly any angle, if accretion disks are indeed generally around a rotating black hole's equator, what forces are causing this?

Is there some Newtonian answer I'm missing, or is it something related to frame dragging or some other effect in general relativity?

submitted by /u/ianjm
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Are there ways to use Fourier analysis on periodic systems on chaos, double pendulum for example?

Posted: 14 Apr 2019 11:03 PM PDT

As I understand it, Fourier analysis lets you break down any sort of periodic function and look at all the waves that add up to it. In the simple double pendulum example, the system is only a combination of two periodic functions, so shouldn't Fourier be able to give you an easily predictable time evolution description?

submitted by /u/_Sunny--
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Are there any major differences between the last couple interglacial periods? (MIS 1, 5, 11)??

Posted: 14 Apr 2019 04:18 PM PDT

When a person has a stroke, are their internal organs affected?

Posted: 14 Apr 2019 04:54 PM PDT

When someone suffers a stroke in one hemisphere of their brain I understand that the opposite half of the body can lose muscle activity due to the death of motor neurons. Are their internal organs affected too? Will one side of their gut lose the ability of peristalsis? Will their lungs/diaphragm be affected similarly?

submitted by /u/SnowyMountain_
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Is all human blood the same color, or will there be inconsistencies based on exactly what is in the blood/ blood type?

Posted: 14 Apr 2019 09:27 PM PDT

When have coral reef been wiped out and come back?

Posted: 14 Apr 2019 08:17 PM PDT

In response to another question about a warmer Earth and its effects on coral reef, a flaired poster mentioned that coral reef have come and gone in the past. Can anyone provide more information on this? When did this occur; how does this occur?

atomfullerene:

Reefs have come and gone throughout earth's history. It's not uncommon for them to get wiped out and reappear after several million years with a new set of reef-forming organisms.

https://www.reddit.com/r/askscience/comments/8fvubk/if_coral_reefs_existed_in_the_past_when_the_earth/dy9a70y?utm_source=share&utm_medium=web2x

submitted by /u/lion342
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