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Tuesday, October 23, 2018

If fuel is not replaced in a nuclear reactor, what happens to the power output over time?

If fuel is not replaced in a nuclear reactor, what happens to the power output over time?


If fuel is not replaced in a nuclear reactor, what happens to the power output over time?

Posted: 23 Oct 2018 03:09 AM PDT

Assuming the cooling pumps continue running and the fuel rods are all just allowed to reach a point of being "spent", what happens if they aren't replaced? My understanding is that spent fuel is more radioactive, but does it produce a different amount of power than newer fuel rods? I'd imagine that spent means the power output is slowly tapering off but when I read that the fuel is more radioactive, that also seems to suggest that it may put out more power.

submitted by /u/willscuba4food
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Men and Women have different warning signs for a heart attack, why is that?

Posted: 23 Oct 2018 07:07 AM PDT

This image provided by u/vivaenmiriana in a thread about life saving facts points out different warning signs. What things might cause this difference in warning signs?

submitted by /u/meanblazinlolz
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Why is the set of real numbers between 0 and 1 uncountable, but not the set of all integers?

Posted: 22 Oct 2018 08:54 PM PDT

The answer that I have found elsewhere is that the integers can be listed as such

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13...

and that the same cannot be done for the real numbers between 0 and 1. I don't see why this is true because I can list them as follows.

0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.01, 0.11, 0.21, 0.31...

Notice that there I have constructed the second list by taking the mirror image of the first list about the decimal point, so there is definitely a 1 to 1 mapping of integers to real numbers between 0 and 1.

The other reason usually given is that if you take a set which is assumed to contain all the real numbers between 0 and 1 then you can create a new number by making the first digit different than the first digit of the first number, the second digit different than the second digit of the second number and so on.

But you can also do this with the integers! Just create a new integer and make different than the first number in the ones place, different than the second number in the 10's place and so on.

Please help me see where I am wrong above.

submitted by /u/Hepheastus
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How have the researchers in this alcohol and dementia study accounted for sociodemographic and health related characteristics?

Posted: 23 Oct 2018 07:45 AM PDT

https://www.bmj.com/content/362/bmj.k2927

"We accounted for several sociodemographic and health related characteristics in the analysis, but residual confounding cannot be excluded as an explanation for the higher risk of dementia among abstainers. Indeed, this group is particular in that it is composed mainly of women from the lower socioeconomic group with higher prevalence of cardiometabolic risk factors and disease at baseline, a pattern that has also been observed in other studies"

Figure 2's caption mentions Cox regression analysis

I suppose I am asking for a simplified explanation. I only have a high school education in maths and statistics. I want to understand whether the higher incidence of dementia in abstainers than light drinkers is due to alcohol in low amounts having some sort of protective effect against dementia or if it's not actually the case and just appears this way due to other factors.

I've seen the rule against homework questions and I can tell you this is definitely not homework. It is a rather uneducated person trying to get his head around science for the sake of his long term health. I know there will be more important factors in protecting myself from dementia than the likely small dementia difference between abstinence and light drinking but surely all protecting factors are important. Dementia is bad.

submitted by /u/grate1438
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How do electric potentials work around the heart in EKG??

Posted: 23 Oct 2018 06:58 AM PDT

Hi everyone. Medical student here who recently started studying EKG. If anyone could help me figure out why is it that every depolarization or repolarization wave ends up as an isoelectric line at the end??

Let me take the P wave as an example. As far as I understood from high school physics once atrial depolarization is finished the entire atria is depolarized while the the entire ventricle is in a polarized state which in turn would lead to a potential difference between the 2 areas of the heart which in turn would lead me to believe that the electrodes would pick up this difference(Let's use lead 2 for example). Yet the ECG shows a 0 difference voltage and thus an isoelectric line. I've been scratching my head for daaays trying to figure this out. Help me.... PLEASE.

submitted by /u/ayazasker
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If everything in outer space is moving away from everything else and constantly expanding, how can 2 galaxies collide?

Posted: 22 Oct 2018 02:18 PM PDT

How/when did we learn that there was no oxygen in space?

Posted: 22 Oct 2018 10:46 AM PDT

Why has nobody come close to Tesla's inventions that were created up to 100 years ago?

Posted: 22 Oct 2018 03:49 PM PDT

Wireless energy in the late 1800s, an oscillator that could cause earthquakes, which was no more than a few feet long and wide. His free energy, his flying saucer designs. Still owning the record for largest man made lightening bolt etc.? Was he that smart?

submitted by /u/Bulbasaur_King
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Why is a pendulums period constant.. until it isn't?

Posted: 22 Oct 2018 07:32 PM PDT

One of the labs I did years ago in highschool involved the measuring of a pendulums period. We all know that a pendulum has a period which is constant regardless of its amplitude. You hold a weight on a string off its axis and it will swing from period to period, and take exactly the same amount of time to move end to end, regardless of the energy put into the system, until you hold the weight a little bit too high, and it swings a little bit too far, and no longer keeps accurate time from end to end. What is happening that causes this phenomenon? I asked my physics teacher decades ago, but he said it was a bit too complicated to answer in class at that point, and I never got back to the question. This has been bothering me for years now, and if anyone can explain it, and explain the math behind the concept, I would be so grateful. Thank you!

submitted by /u/spoonguy123
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How does a quantum particle decohere into the environment if the environment is quantum too?

Posted: 22 Oct 2018 09:32 PM PDT

My philosophy professor said we are not affected by quantum uncertainty at "our level" 30 orders of magnitude above the planck length and therefore the observer dependent states don't have bearing on free will. This is due to decoherence. I'm struggling to understand how this is the case.

submitted by /u/Africanus1990
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Why does decay happen as a first order reaction?

Posted: 22 Oct 2018 04:17 PM PDT

I understand how to calculate half life. I am just wondering why the rate of the reaction changes over time?

submitted by /u/jimmyth3xplod3r
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How "strong" of a vacuum can you make by pulling a piston out of a cylinder?

Posted: 22 Oct 2018 11:48 PM PDT

Asking for my dad - he sent the following explanation of his question, and I couldn't really answer: "Suppose you have a piston at the bottom of a cylinder, which has no opening at the bottom. When you draw the piston out, a vacuum is created.

It is easy to imagine that very quickly the pressure difference will become about 14.7 psi (atmospheric pressure) outside, and getting close to zero inside.

The question is, what happens next, if you continue to pull the piston? It is relatively easy to overcome 14.7 psi.

Is it impossible to pull it any further? Will there be another force holding the piston back? If so, what force?

Maybe, you can continue to pull the piston out—after a certain point the pressure differential becomes about 14.7 psi and that's all you have to overcome for the rest of the stroke. What I'm saying is the pressure difference can't be more than 14.7 psi, and yet you can continue to increase the volume inside the cylinder.

Or maybe the reduction of pressure close to a vacuum inside the cylinder becomes non linear compared to the increase in volume (contrary to Boyle's Law).

Apparently, a perfect vacuum is impossible. But the references I've found so far are not consistent on the meaning of "perfect vacuum." It could mean zero pressure, or it could mean no molecules of air, which might not be the same thing. I think "impossible" probably means it's difficult to extract every last molecule of gas from a chamber—the fewer they become, the harder it is to capture them."

submitted by /u/lasiusneglectus
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How to Compare Experimental data with Theory?

Posted: 22 Oct 2018 12:58 PM PDT

I've got experimental data from a that shows the intensity of light against position for a diffraction pattern and a theoretical curve by imputing parameters into a function. I want to compare how good a fit the theoretical curve is to the experimental data. My demonstrator suggested a chi-square test but when I researched this it seemed to be for observed and expected frequency of results. Any help would be much appreciated.

submitted by /u/LegalBiscotti
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Solar panel reaction time from light to dark?

Posted: 22 Oct 2018 06:42 AM PDT

Does a solar panel's voltage output drop to zero instantly if going from light to complete dark? Here's an example: In a completely dark room there is a 12 inch by 12 inch solar panel and a spotlight that puts out a 12 inch diameter beam of light. The spotlight is aimed directly on the solar panel and then switched on. The solar panel reaches its maximum output for the spotlight. The spotlight is then switched off. Does the solar panel's voltage output instantly drop to zero or does the reaction in the solar panel continue for some time?

submitted by /u/u3n3ts
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Why can cutting off the Brain's Oxygen supply sometimes cause euphoria?

Posted: 22 Oct 2018 09:14 AM PDT

What is the maunderminimum?

Posted: 22 Oct 2018 04:44 PM PDT

My co worker keeps talking about it and I'm curious. What is it?

submitted by /u/Daddydabs
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How do power outlet ethernet adapters work?

Posted: 22 Oct 2018 06:48 AM PDT

I have looked all over the internet and am unable to find out how they actually work. You simple plug them into a power outlet, and assuming the outlet is on the same power circuit as your router, it can function as an ethernet port.

submitted by /u/Just4TehLulz
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Why do fish come to the water surface to breathe when there is heavy fog?

Posted: 22 Oct 2018 09:13 AM PDT

I have a 1 acre pond with 19,000 fish of an average weight of 300 grams. In the last few days there has been heavy fog between 6:30 am to 8 am(approximately 27 °C). I have noticed that a large number of fish have come to the surface to breathe and go back into the water once the fog clears.

I have included a link to a video below:

https://photos.app.goo.gl/yCN1MLki2qFzDps36

submitted by /u/jonathanrjpereira
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Why does a water droplet hitting a extremely hot surface only produce a hissing sound at the start?

Posted: 22 Oct 2018 07:01 AM PDT

At slightly lower temperatures, water boils off and continuously makes a sizzling sound for the duration its boiling. However this does not seem to be the case when the temperature of a surface is much higher than the boiling point of a liquid.

submitted by /u/tet2323
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How is dried permethrin on surfaces safe for cats when wet permethrin is dangerous?

Posted: 22 Oct 2018 07:09 AM PDT

Monday, October 22, 2018

AskScience AMA Series: I'm Adam Boyko, canine geneticist at Cornell and founder of dog DNA testing company, Embark. We're looking to find the genes underlying all kinds of dog traits and diseases and just discovered the mutation for blue eyes in Huskies. AMA!

AskScience AMA Series: I'm Adam Boyko, canine geneticist at Cornell and founder of dog DNA testing company, Embark. We're looking to find the genes underlying all kinds of dog traits and diseases and just discovered the mutation for blue eyes in Huskies. AMA!


AskScience AMA Series: I'm Adam Boyko, canine geneticist at Cornell and founder of dog DNA testing company, Embark. We're looking to find the genes underlying all kinds of dog traits and diseases and just discovered the mutation for blue eyes in Huskies. AMA!

Posted: 22 Oct 2018 04:00 AM PDT

Personal genomics is a reality now in humans, with 8 million people expected to buy direct-to-consumer kits like 23andme and AncestryDNA this year, and more and more doctors using genetic testing to diagnose disease and determine proper treatment. Not only does this improve health outcomes, it also represents a trove of data that has advanced human genetic research and led to new discoveries.

What about dogs? My lab at Cornell University focuses on canine genomics, especially the genetic basis of canine traits and disease and the evolutionary history of dogs. We were always a bit in awe of the sample sizes in human genetic studies (in part from more government funding but also in part to the millions of people willing to buy their own DNA kits and volunteer their data to science). As a spin-off of our work on dogs, my brother and I founded Embark Veterinary, a company focused on bringing the personal genomics revolution to dogs.

Embark's team of scientists and veterinarians can pore over your dog's genome (or at least 200,000 markers of it) to decipher genetic risks, breed mix, inbreeding, and genetic traits. Owners can also participate in scientific research by filling out surveys about their dog, enabling canine geneticists to make new discoveries. Our first new discovery, the genetic basis of blue eyes in Siberian Huskies, was published this month in PLOS Genetics.

I'll be answering questions starting around 2:30 ET (1830 GMT), so unleash your questions about genomics, dogs, field work, start-ups or academia and AMA!

submitted by /u/AskScienceModerator
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How do lakes deep underground maintain an ecosystem with no energy input from the Sun?

Posted: 21 Oct 2018 06:35 AM PDT

Why does Sweden have temperate climate while on the other side in Canada they have polar climate?

Posted: 22 Oct 2018 07:47 AM PDT

What would be the effect of showering in pure water?

Posted: 22 Oct 2018 08:32 AM PDT

Hard water is known to dry out the skin but what would pure water do?

submitted by /u/PHealthy
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What findings exist on studies made on the effect of “screen time” (TV, tablets, etc.) in cognitive development in children?

Posted: 21 Oct 2018 10:23 PM PDT

What are the advantages/disadvantages of a ternary computer vs a binary computer? Why are almost all modern computer binary computers?

Posted: 21 Oct 2018 06:38 PM PDT

What causes tall cliff shorelines?

Posted: 22 Oct 2018 07:23 AM PDT

This one in Ireland for instance

imagine finally finding land, after wandering aimlessly in the sea only to realize it's practically impenetrable

submitted by /u/savvyfuck
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Does Neurodegeneration occur in unsupervised Artificial Neural Networks?

Posted: 21 Oct 2018 10:32 AM PDT

If a bilingual person were to experience full-on retrograde amnesia, would they retain the ability to speak both of their languages?

Posted: 21 Oct 2018 04:34 PM PDT

When creating yoghurt, recipes call for the starting temperature to be 110-115F. Will a lower starting temperature impact the outcome?

Posted: 21 Oct 2018 07:51 PM PDT

Most recipes I have found are fairly diligent about standing by with a thermometer to add the starter culture once the temperature hits 110-115F. The temperature is then maintained at that temperature for some time. If the starter culture that is being added is at room temperature, and the pasteurized milk is allowed to cool to below 110F, then the entire business is heated back up to 110-115F, what are the consequences from the perspective of the bacteria? Does the few minutes that the milk spends getting back up to temperature really make a difference? I imagine that the bigger concern is that you add the culture too early and they are killed by the high temperatures.

submitted by /u/gradygradygrady
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What’s the process behind determining an organism’s species by examining its DNA?

Posted: 21 Oct 2018 07:56 PM PDT

Suppose you have an organism and collect some DNA to determine its species. Now what? What technology is required? How is it done? What is the process called? What is used as a reference guide to compare its DNA? Whose job is it to even do something like this? And so forth.

submitted by /u/MrPancake101
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How do astronomers know how old a star is/how old they can get?

Posted: 21 Oct 2018 03:56 PM PDT

What are the main differences between the human and the brain of apes?

Posted: 21 Oct 2018 07:07 AM PDT

If you cut open up the skull of a human and an ape, what fundamental differences you can observe?

submitted by /u/ManagerOfLove
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Endothelial cell’s access to Oxygen?

Posted: 21 Oct 2018 01:34 PM PDT

Since there is no oxygen in the red blood cells in veins, how do the cells that make up the veins themselves actually get the oxygen they require to function?

I assume that the cells in arteries can just take it straight from the blood.

submitted by /u/charliebewsey7
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Do materials that conduct heat better than others melt more quickly?

Posted: 21 Oct 2018 02:59 PM PDT

Say we have two metals. Metal A conducts heat better than B. Will A melt first?

submitted by /u/HMS-Dreadnought
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With advances in immunology and medicine, how has our immune system changed over the last hundred years?

Posted: 21 Oct 2018 01:09 PM PDT

You know when you can't sleep but your trying to so you lay there with your eyes closed? Does that time spent awake but trying to sleep help you in any way or is it wasted time?

Posted: 20 Oct 2018 05:58 PM PDT

What criteria are used to judge an animal’s intelligence?

Posted: 21 Oct 2018 10:41 AM PDT

Why can’t Windows uninstall more than one program at the same time?

Posted: 21 Oct 2018 01:02 PM PDT

When you have a rash that is an allergic reaction to something you ingested, what makes it “decide” where on your body to show up? Why doesn’t it just show up everywhere on your body?

Posted: 20 Oct 2018 07:12 PM PDT

Why is glass translucent/transparent? Is it a molecular arrangement thing? Is all clear matter clear for the same reason, such as water and diamond?

Posted: 20 Oct 2018 05:50 PM PDT

How do you determine if an animal is from a different species ?

Posted: 21 Oct 2018 09:36 AM PDT

How do biologists determine if an animal , hybrid between two species, is not from a new different species. Is it just that if it's sterile , it cannot be a new species ? And also , how do they know that the animal is sterile?

submitted by /u/wolfgang852
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Sunday, October 21, 2018

Does electricity effect water freezing?

Does electricity effect water freezing?


Does electricity effect water freezing?

Posted: 20 Oct 2018 08:09 AM PDT

If you put electrical current through water will it prevent it from freezing? Speed the freezing process up?

submitted by /u/Professional-lounger
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What happens within your body for an itch to occur?

Posted: 20 Oct 2018 02:30 PM PDT

How do celestial bodies become tidally locked?

Posted: 20 Oct 2018 04:22 PM PDT

How can spider legs keep moving after they're detached from the body?

Posted: 20 Oct 2018 10:03 AM PDT

Is there way to determine how fast program will execute task?

Posted: 20 Oct 2018 03:20 PM PDT

I know some programming languages are faster and some slower, can we predict how much time computer need in particular language?

submitted by /u/Dragonaax
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What exactly does it mean for something to be not locally real?

Posted: 20 Oct 2018 05:10 PM PDT

I have a decent familiarity with QFT. I prefer the Debroglie-Bohm interpretation as it allows for excellent models to explain and remember how things behave. It's easy on the intuitions. I realize it violates Belle inequalities in that it requires the universe is not locally real. What exactly does that mean?

submitted by /u/fox-mcleod
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Why does the oxide layer on aluminum protect it from corrosion, but the oxide layer on iron does not?

Posted: 20 Oct 2018 11:16 AM PDT

I've seen a lot of rusted parts on cars, light poles, bolts and everything in between rust all the way through over the years, but aluminum, despite oxidizing also, seems to be immune to the same effects of an oxygen rich environment. Why?

submitted by /u/newtrawn
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What happens to the pieces of an atom after it is split?

Posted: 20 Oct 2018 06:10 PM PDT

I'm not very knowledgeable on the topic of physics or fission in general, but I was curious about what happens to the halves of the atom after it splits. Do they disappear?

submitted by /u/greenbeanleanscreen
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How does removal of leaf fall affect trees in urban environments over a long term?

Posted: 20 Oct 2018 05:49 AM PDT

There are a staggering number of leaves on the ground at the moment, and most of those leaves seem to be removed and ferried off away out of our cities.

Even a gardener at home will largely remove the leaves, with some maybe composting.

Over a very long period of time, how does removing all these recyclable nutrients affect the trees left behind? To what degree are we interrupting the Nitrogen Cycle?

submitted by /u/OhMoSex
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Why are ethanol bottles in the chemistry lab labelled 'staining reagent' ?

Posted: 20 Oct 2018 03:36 PM PDT

Can Saturns "Rings" be individually identified?

Posted: 20 Oct 2018 04:48 AM PDT

Looking at Saturn from a Lay-persons point of view, the rings orbiting the planet always appears to have clear, striated layers. Are these actually layers that can be individually identified and distinguished, or are they more of an ever changing flow of layers. An additional point, in the case that they are individually identifiable, do the layers have name in the way that most astronomical bodies have names?

submitted by /u/Carpy444
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How does one way glass work?

Posted: 20 Oct 2018 05:51 AM PDT

How much of the Indian ocean did we map during the search for MH370?

Posted: 20 Oct 2018 02:57 AM PDT

Why only Anopheles transmit malaria?

Posted: 20 Oct 2018 10:28 AM PDT

Hello,

I'm medical school freshman and we had citology and parasitology cycle this month. We were talking a lot about Culex and Anopheles but lectors didin't emphasize on why only Anopheles transmit plasmodium malaria, vivax, ovale, etc., and Culex don't?

submitted by /u/ocrynox
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How do Space and Time really work when going through a Worm hole?

Posted: 20 Oct 2018 08:11 AM PDT

Are hydrogen bonded, halogen bonded, and Lewis acid-base complexes all due to electrostatic attractions?

Posted: 20 Oct 2018 08:02 AM PDT

Hello,

I'm trying to straighten out some definitions between hydrogen bonding, halogen bonding, and Lewis acid-base complexes. To me, these three association interactions are all at a high level all driven by electrostatic forces (partial positive attracted to partial negative). I have put the following together as part of something I'm writing and want to run it by the r/askscience community (cross posted to r/chemistry as well). If there is something more to these three interactions than the "partial positive / partial negative", then I'd appreciate any suggestions (or recommendations in the literature) as to how to better describe each interaction and the differences.

Association interactions strongly impact phase behavior and thermodynamic properties. Association is the assembling of separate molecular entities into a complex where the bonding between the components is weaker than in a covalent bond. (IUPAC Compendium of Chemical Terminology, Gold Book, 2014). The most common association interactions are:
- Hydrogen bonding occurs when there is an attractive interaction between a hydrogen atom from a molecular fragment such as O–H or N–H and an electron rich region such as a lone pair or a π-bond. (Definition of the hydrogen bond (IUPAC Recommendations 2011), 2011)
- Halogen bonding occurs when there is attractive interaction between an electrophilic region associated with a covalently bonded halogen atom such as R-Cl, R-Br, or R-I and an electron rich region such as a lone pair or a π-bond region (Definition of the halogen bond (IUPAC Recommendations 2013), 2013).
- Lewis acid-base interactions occur where a Lewis acid (an electron pair acceptor) binds to a Lewis base (an electron pair donor) to form an electron donor-acceptor complex (IUPAC Compendium of Chemical Terminology, Gold Book, 2014).
The forces involved in the formation of hydrogen bond, halogen bond, and Lewis acid-base complexes are dominantly electrostatic. In all three cases, it can be said that an electron donor/electron acceptor relationship exists. If an interaction is primarily due to dispersion forces, then it would not be characterized as a hydrogen bond, halogen bond, or Lewis acid-base complex (Definition of the hydrogen bond (IUPAC Recommendations 2011), 2011).
Hydrogen bonding, halogen bonding, and Lewis acid-base interactions typically result in geometry distortion of bonded monomers relative to the un-bonded monomers. In all three cases, bonding typically results in penetration of the van der Waals volumes. For hydrogen bonded and halogen bonded complexes, the primary distortion is a lengthening of the R-H or R-X bond. For Lewis acid-base complexes, there is no typical distortion so bond length and bond angle changes will depend on the compounds involved. In all cases, the geometry distortions caused by complex formation can be observed with IR and Raman spectroscopy.

Thank you in advance for any insights or suggestions you can provide!!

John

submitted by /u/PR_SRK_LKP
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Why are planetary rings not all around planets and instead just form a like like Saturn?

Posted: 20 Oct 2018 07:44 AM PDT

If gravity is omni-directional and debris floats around in space all the time why has none of the planets with rings have other things formed in different directions or even separate spaces on the planet never intersecting?

submitted by /u/TansenSjostrom
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