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Wednesday, August 28, 2019

How can cheese be "aged" so long, but when it's in my fridge for longer than a few weeks it goes mouldy?

How can cheese be "aged" so long, but when it's in my fridge for longer than a few weeks it goes mouldy?


How can cheese be "aged" so long, but when it's in my fridge for longer than a few weeks it goes mouldy?

Posted: 27 Aug 2019 01:27 PM PDT

AskScience AMA Series: My name is Margaret Race, and I work on planning human missions to Mars. Specifically, I work on behind the scenes preparation and interdisciplinary input on planetary protection. AMA!

Posted: 28 Aug 2019 04:00 AM PDT

My name is Margaret Race, and I work on the behind the scenes prepatation for planetary protection in planning human missions to Mars.

We just celebrated the 50th Anniversary of the Apollo Moon Landings, a milestone in human achievement. We've gotten so used to headlines about new technologies, far out exploration and diverse science discoveries, that we hardly think about what goes into the planning and preparation behind the scenes. It involves way more than just rocket scientists and astronauts! (How else would a marine biologist and ecologist like me end up working with NASA on missions to Mars and planetary protection!?)

It's surprising how many different types of people and careers are involved with NASA and the space community as they plan future missions, whether in Earth orbit, to the Moon, and someday, even to Mars. The careers and challenges will surprise you: it involves all the STEM fields -- science, technology, engineering and math-- and also includes input from an assortment of other fields, from law, ethics, and emergency management, to communications, movie making and even philosophy. To paraphrase Dr. Seuss: Oh, the places we'll go... and the careers we need! AMA about the assorted questions that are addressed in planning long duration space missions beyond Earth.

My bio and CV: https://seti.org/our-scientists/margaret-race

I'll be available for questions at 10am PDT (1 PM ET, 17 UT), AMA!

submitted by /u/AskScienceModerator
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How does a rifle barrel regain its accuracy when cooled down after multiple consecutive shots?

Posted: 28 Aug 2019 07:07 AM PDT

I think physics is the appropriate flair. When a rifle with a thin barrel fires multiple consecutive shots and the barrel overheats, the rifle's repeatable accuracy is affected. When the barrel cools down, repeatable accuracy can again be achieved. Why doesn't the barrel remain in its heated and possibly warped state?

submitted by /u/LightSlayerPantyOn
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Ask Anything Wednesday - Engineering, Mathematics, Computer Science

Posted: 28 Aug 2019 08:12 AM PDT

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Engineering, Mathematics, Computer Science

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!

submitted by /u/AutoModerator
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What is the smallest size of object we can see at a distance?

Posted: 28 Aug 2019 03:10 AM PDT

Suppose you have a spherical ball of diameter d, placed at a distance L from you, and you have perfect eyesight, then what is the maximum distance at which you can see the ball?

I read somewhere that minimum angle of resolution is around 150 micro radians.

So s = rθ

And at a distance of 1000 meters, the smallest object we can see is 1000*150/106 or 15 centimeters across. Is this correct? If not then how do I calculate?

submitted by /u/HighExergy
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Light visually bending round objects?

Posted: 28 Aug 2019 03:55 AM PDT

So I'm very curious, and can't find info on it by just vaguely googling it.

Say you close one eye, and put a pen or something in close proximity of the other so it's too close to focus on, the objects in the background seem to bend and warp round the blurry edges of the pen when moved?

How exactly does this work? It's really bothering me.

submitted by /u/JasonY95
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Can charged ions increase airflow over a wing?

Posted: 28 Aug 2019 05:06 AM PDT

Can an electric field potential increase velocity of air over a wing to produce lift? What if the angle of attack was was perpendicular to the chord line, and the velocity of airflow was accelerated by an electric field potential? I'm attempting to show that a 90° angle of attack creates upward lift if the air velocity over the "wings" camber line is greater than the velocity of air at the chord line. I want to see if it still works inside a box. I would draw a picture, but this subreddit is text only.

submitted by /u/DandelionTheory
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What’s inside of oil free radiators?

Posted: 28 Aug 2019 04:15 AM PDT

Can an FPGA (Field Programmable Gate Array) change its hardware mid-computation?

Posted: 27 Aug 2019 08:52 PM PDT

Maybe the premise of my question is incorrect, sorry I'm new to the concept of FPGA's.

Say you had an AI problem that you were writing code for with Python on an FPGA as the hardware. Could the Python script make calls to the HDL (hardware description language) to change the hardware while its solving the problem, and vice versa? Like if you wanted the software to optimize the hardware during certain parts of the problem, and the other way around.

submitted by /u/FakeNewsFlash
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Is there a single place on earth that is regularly vulnerable to every kind of natural disaster? Hurricanes, tornadoes, earthquakes, fire, floods, blizzards, volcanos, avalanches, mud slides, etc.

Posted: 28 Aug 2019 05:48 AM PDT

Does frequent masturbation reduce androgen receptors?

Posted: 27 Aug 2019 05:51 PM PDT

I've heard that excessive masturbation reduces androgen receptors and in turn, doesn't allow your body to use testosterone. Is this true?

submitted by /u/n00b12
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What (if any) are the differences between results from fMRIs of people viewing an object versus people thinking about a picture of the object?

Posted: 28 Aug 2019 04:52 AM PDT

Just thinking in terms of what we perceive physically versus what we recall, and if we "see" with our mind's eye or if we're just thinking of the object's attributes.

submitted by /u/taylorda
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Is there a delay of the tides when the moon get over a specific point on hearth?

Posted: 28 Aug 2019 04:27 AM PDT

Is the tide late compare to the position of the moon at a perpendicular position from the ground?

submitted by /u/EtG_Gibbs
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Why do so many medications interact with MAOIs?

Posted: 28 Aug 2019 04:08 AM PDT

My fiancée is on Prozac. She's been developing a cold recently. I offered her some of my go-to remedies, and she turned them down because it says "do not take if you are on an MAOI", which Prozac is.

But it got me thinking: why is this the case? What is it about MAOIs, or what is it about cold mess for that matter, that cause an interaction?

submitted by /u/boundbylife
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How did HIV/AIDS pass onto humans?

Posted: 27 Aug 2019 11:31 AM PDT

When family planning is it possible to screen for autism?

Posted: 27 Aug 2019 06:02 PM PDT

I have a brother who's profoundly affected by his autism but no other family members who have it. I'm wondering when I'm planning to have children is there a way I can tell if my kids would be affected?

submitted by /u/wasterspacer
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Do we all see colors the same way ?

Posted: 27 Aug 2019 11:58 PM PDT

Hi,

Do we have any evidence that we all see colors the same way ?

Apart from colorblind people, how can we tell than when one sees this, noone sees this ?

Also, couldn't colors be specific to each indidivual ? Some kind of mind creation ?

Thanks

submitted by /u/TorpazZz
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[Chemistry] Can TNT explode in a furnace of a ship/train without a detonator?

Posted: 27 Aug 2019 10:18 AM PDT

Not sure how to flag it, so one of each it is.

I've read an article on Wikipedia about Soviet partisans using pure TNT, melted from artillery shells, disguised as coal to hinder Nazi locomotive transportation.
There was special emphasis on how it was achieved without using dedicated devices to initiate the detonation.

Allegedly, coal furnace conditions of high heat and pressure/not enough room to just burn - were enough for explosion to occur. But there was no sources cited. I tried to Google it, and everywhere it lead me, I've read how stable it is. How it just burns, without big badaboom.
Nowhere I could find specific example of burning it in a furnace, though.

Wikipedia article on TNT itself did mentioned how "melting point of TNT is low enough for spontaneous explosion to not happen", or something along those lines, implying that there is a temperature where it might. But no elaboration on that anywhere I could find.

Found a research paper on high temperature - high pressure behavior of TNT, but from what I gathered(and most of it just flew right over my feet) it does not answer my question. It was more about molecular structure or smth.

And so, here I am. Help?

Edit:

My reddit app sends me notifications about replies, I see that there is 10 replies in total listed, but in thread I've only seen two level-1 and one level-2. Tried different app, different browsers, different accounts. Same thing.

Google tells me it might be automod hiding them, but why tho?

submitted by /u/KindaSorta_ThrowAway
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Is there a difference between the Z-Scheme and Non-Cyclic photosynthesis?

Posted: 27 Aug 2019 09:32 PM PDT

Is there a difference between those two? My professor said that Non-cyclic just refers to the production of NADPH (not ATP) in the Light dependent reactions, and the Z-scheme refers to just what plants do, producing both ATP and NADPH. I looked online and cant find anything about a photosynthesis path that JUST produces NADPH. I know cyclic produces just ATP, but does non-cyclic just refer to the production of NADPH and Z scheme refer to the production of both?

submitted by /u/PossibleJelly
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Where does earth oxygen come from?

Posted: 27 Aug 2019 08:32 AM PDT

Ive been reading a lot of reports that 20% of the Earths oxygen comes from the Amazon Rainforest. However, I always understood that 80% of the Earths oxygen comes from phytoplankton. So this doesn't really add up since we have a lot more sources of oxygen than just these too. and even if these two numbers are close, I feel that all the trees, etc make up >5% of the worlds oxygen. What am I missing? What would be a true breakdown of the worlds oxygen by source.

submitted by /u/MUZZIES
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How did burying or burning our dead become a common practice among most cultures, even isolated ones?

Posted: 27 Aug 2019 01:46 PM PDT

Why is it said that some languages (like Assembly, C, BASIC etc) are "faster" than others (Like C++, C#, Python etc)? If all code is converted to machine code and then compiled, then why does it matter in which language it was programmed first?

Posted: 27 Aug 2019 05:37 AM PDT

What are the sound-transmission consequences of ionizing a gas (cold plasma)?

Posted: 27 Aug 2019 10:51 AM PDT

Let's take a large tank filled with some neutral gas at surface air pressure, 70 degrees in temp. We apply some very powerful charges--basically converting it to cold plasma, as close to 100% as possible. Same temps. Does mutual repulsion greatly increase the pressure? Are acoustic waves transmitted more rapidly, or with greater power? If the pressure of the plasma were reduced back to its former value, does the fact of ionization itself affect vibratory transmission on a "large" scale?

And--does this affect the heat capacity of said gas?

submitted by /u/losala
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Tuesday, August 27, 2019

AskScience AMA Series: I'm Guy Leschziner, neurologist, sleep physician, and author of "The Nocturnal Brain: Nightmares, Neuroscience and the Secret World of Sleep". AMA!

AskScience AMA Series: I'm Guy Leschziner, neurologist, sleep physician, and author of "The Nocturnal Brain: Nightmares, Neuroscience and the Secret World of Sleep". AMA!


AskScience AMA Series: I'm Guy Leschziner, neurologist, sleep physician, and author of "The Nocturnal Brain: Nightmares, Neuroscience and the Secret World of Sleep". AMA!

Posted: 27 Aug 2019 04:00 AM PDT

Hi, I'm Guy Leschziner, neurologist, sleep physician, and author of "The Nocturnal Brain: Nightmares, Neuroscience and the Secret World of Sleep". In this book, I take you on a tour of the weird, wonderful, and occasionally terrifying world of sleep disorders - conditions like insomnia, sleepwalking, acting out dreams, narcolepsy, restless legs syndrome or mis-timed circadian clocks. Some of these conditions are incredibly rare, others extremely common, but all of these disorders tell us something about ourselves - how our brains regulate our sleep, what sleep does for the brain, and why we all to some extent experience unusual phenomena in sleep.

You can find out some more at

I'll be on at 11am ET (15 UT), AMA!

submitted by /u/AskScienceModerator
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Are boiling points and melting points affected by isotopic value?

Posted: 27 Aug 2019 03:31 AM PDT

I know that these state change points are dependent on bonds between them but i was just wondering, is it only dependent on the electrons for their bonds or do the neutrons affect it. Such as water, if the elements in it were different isotopes such as hydrogen with a neutron and O-18 would this change the boiling point from 100 celcius or have no affect?

submitted by /u/goldlord44
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In historical,natural climate change, what caused temperature to drop after a while? Will this happen again with human caused climate change?

Posted: 27 Aug 2019 05:10 AM PDT

So historically, the earths climate has gone trough various cycles of hot periods and cold periods. I know that this time is different, but I was wondering what exactly caused the climate to cool again after a hot period?

I know that there are 'breakaway' climate change triggers and was wondering how those were reserved in the ancient past.

submitted by /u/lolspek
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Why does it hurt when disinfectant is applied to wounds?

Posted: 26 Aug 2019 02:09 PM PDT

Are amazon fires actually at normal rate from previous years?

Posted: 26 Aug 2019 08:52 AM PDT

I've started to see severals people saying that amazon fires are actually happening at normal rates or even lower than previous years like 2005. The graph that is used is the one that is in globalfiredata site:

https://www.globalfiredata.org/forecast.html#amazonas

Now, I understand that fire count is different that fire sizes but is this fire actually worse that the situation we had in 2005 during Lula presidency? Every time I try to look about new-sources about this fire the only thing I can found is that "Is 84% higher than previos year" without going further.

https://www.bbc.com/news/world-latin-america-49415973

Is the situation actually worse that the situation we had previous years? And why

Also about deforestation rates:

https://news.mongabay.com/2019/05/new-report-examines-drivers-of-rising-amazon-deforestation-on-country-by-country-basis/

The "peak" were in previous years. Why is the situation actually worse now?

Thanks!

submitted by /u/marianitten
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Could the gas giant planets ever dissipate?

Posted: 26 Aug 2019 06:00 AM PDT

Why did we create the equator? (interested in equator experts)

Posted: 26 Aug 2019 05:36 PM PDT

Helping to develop a series on the power of invisible things, and the equator is going to be a big part of the show, so i was wondering what i should know about the equator and specifically who the experts on the subject are?

how have we determined the importance of an invisible line that exists only to us?

submitted by /u/RedEdBrown
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Why is it that, at a younger age, we can get away with eating unhealthily yet still have so much energy, but, at an older age, you can feel the negative effects of unhealthy eating pretty quickly? Is there a biological reason?

Posted: 26 Aug 2019 02:43 AM PDT

Is there a name for the actual origin of the wind, like how a river has headwaters?

Posted: 26 Aug 2019 03:30 AM PDT

Do ants communicate when they find food?

Posted: 26 Aug 2019 02:33 AM PDT

We are doing an experiment regarding communication between ants. In the experiment we plan to have two tubes, where one of tubes has a lump of sugar at the end of it and the other tube is empty. Our hypothesis for this is that the ants in the tube with the sugar in it would communicate with each other that there is food at the end of the tube and go faster to the end of the tube.

Our main problem is that how can we prove that if they go faster, that it is because they communicated and not because of some different factor?

submitted by /u/PauliPoikajarvi
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Do earthquakes make soil more nutrient rich from moving soil that's underground around?

Posted: 26 Aug 2019 12:35 AM PDT

Living in Japan it's easy to find fruits like grapes that are massive, among other fruits too. They're expensive because of the growing methods but I was wondering if earthquakes help refresh soils nutrients allowing them to reach large sizes.

submitted by /u/GoblinGimp69
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How will the heat from the burning Amazon affect weather elsewhere?

Posted: 26 Aug 2019 05:47 AM PDT

Monday, August 26, 2019

AskScience AMA Series: I'm Dr. Paul Knoepfler, stem cell and CRISPR researcher, here to talk about how you might build a real, fire-breathing dragon. AMA!

AskScience AMA Series: I'm Dr. Paul Knoepfler, stem cell and CRISPR researcher, here to talk about how you might build a real, fire-breathing dragon. AMA!


AskScience AMA Series: I'm Dr. Paul Knoepfler, stem cell and CRISPR researcher, here to talk about how you might build a real, fire-breathing dragon. AMA!

Posted: 26 Aug 2019 04:00 AM PDT

Hello! I'm Dr. Paul Knoepfler, stem cell and CRISPR researcher. My 17 year old daughter Julie and I have written a new book How to Build a Dragon or Die Trying about how you might try to make a real, fire-breathing, flying dragon or other cool creatures like unicorns using tech like CRISPR and stem cells. We also satirically poke fun at science hype. We're here to answer your questions about our book, the science behind it, and the idea of making new organisms. AMA!

We're planning to come online at noon Eastern (16 UT), AUA!

submitted by /u/AskScienceModerator
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what rock are more prone to rockslides? how safe are conglomerates?

Posted: 26 Aug 2019 04:12 AM PDT

During an earthquake, would the shaking be more intense if one were beneath the crust?

Posted: 26 Aug 2019 07:58 AM PDT

Do spiders have concept of memory / facial recognition?

Posted: 26 Aug 2019 07:03 AM PDT

bit of a story

Last week I noticed a spider on the side of the house. I didn't kill it because they the small ones that kill little insects. Then one day i took out the step ladder which was apparently connected to the webs and accidentally destroyed parts of the web, i say sorry and go on to do my task. I came back the next day to return the ladder and see that it has rebuilt its house, but everytime i go there now i get slinged with webs. Never got slinged before i destroyed its house.

submitted by /u/ToYourMotherAskHer
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Why do Riverbeds always consist of stones and not dirt?

Posted: 26 Aug 2019 02:53 AM PDT

Like, how did the stones get there? Or did they just form there somehow because of the water?

submitted by /u/shayan012
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How do bees know when they have collected enough pollen?

Posted: 25 Aug 2019 04:21 PM PDT

I was out taking pictures of some bumble bees (American Bumble Bees if I identified them correctly) the other day and I noticed that they all appeared to be covered in pollen. So much that it was falling off some of them as they flew from flower to flower. I was wondering at what point they realized it was time to go back to the hive and unload?

submitted by /u/CJamesEd
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Are there any animal species where the male to female ratio is not very evenly split?

Posted: 25 Aug 2019 12:19 PM PDT

Why Wasn't the James Webb Space Telescope Designed to be Assembled in Space?

Posted: 26 Aug 2019 01:55 AM PDT

How does Reynolds' number work?

Posted: 25 Aug 2019 10:30 AM PDT

So from what I've studied, It seems to be the case that when R is less than 500, it's a condition for laminar flow, and if greater than 1000, it is turbulent flow.

But between 500 and 1000, a few textbooks referred to it as 'unsteady' flow. How is that different from turbulent flow? And is the Reynolds number prediction always valid? Or is it just a likely case?

submitted by /u/hyperclaw27
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Fire is part of the life cycle of many forests. It kills old trees and allows me ones to grow. What is the role of fire in the life cycle and history of fire in the Amazon forest?

Posted: 25 Aug 2019 05:38 AM PDT

Many forests, especially coniferous forest need fire as part of their life cycle. New trees can't compete with the older, taller trees and in some cases fire is required for pine cones to release their seeds.

What is the role of fire in the life cycle of the Amazon forest? As long as forest is allowed to regrow then is fire as bad as we are led to believe?

submitted by /u/RowingCox
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How much does chronic sleep deprivation affect pubertal development?

Posted: 25 Aug 2019 05:01 AM PDT

Coming from a third world nation, I made sure to work extra hard in high school to try and get accepted into a US institution for higher education. I ended up with a full ride at a fairly prestigious college, but at the cost of my own health. I must have been sleeping about 3-4 hours a day on average during weekdays and about 6-8 hours on weekends and whenever school was out. This went on from the second half of 9th grade until 4-5 months before graduation. I kinda ate a lot of junk food as well.

Now I regret it to some extent because I think it may have stunted my bone growth in terms of both height and circumference (robustness). I ended up the same height as my father (176 cm) but I am noticeably slighter in build and I feel as though I wasted a lot of my growth potential. What does science have to say?

submitted by /u/batmantsogt
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Why is the smallpox vaccine delivered with a bifurcated needle instead of a hypodermic needle?

Posted: 25 Aug 2019 01:16 AM PDT

Does sand act as a carbon filtration medium for the Earth's oceans?

Posted: 25 Aug 2019 11:04 AM PDT

Has research been done on analyzing if CNNs that classify related classes share similar feature maps?

Posted: 25 Aug 2019 10:18 AM PDT

I am aware of feature visualization research using tools such as activation maximization to approximate what types of features are captured by each feature map in a convolutional neural network (CNN). However, I do not know of papers determining if CNNs that classify related classes have similar feature maps. One example of "related" classes that are ones "subparts" of one another.

For instance, let there be a classifier called A which has "ham" as a class. Let there also be a classifier called B which has "ham sandwich" as a class. Is classifier B expected to have feature maps in its intermediate layers which identify ham? If so, can we expect classifier A to have some feature maps that are similar to those of classifer B because both need to identify what "ham" is to identify "ham sandwich?"

I know the classification isn't always as cleanly composable as this, as ham sandwich's features may have something that ham will never have (say, the ham being between two breads as the more important feature to look for) and thus classifier B may not even look for ham at all, so I am looking to see what is the current popular consensus, if any, on if classifier's feature maps for different classifiers can be related in such a manner.

Are there papers or blog posts which found specific classifiers that have these composable feature map properties with one another? If so, who are the more prominent researchers tackling this topic, and what major papers have been published discussing it?

submitted by /u/dsdsdg
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Why do people consider Gabapentin a “GABA” drug like benzos and alcohol?

Posted: 25 Aug 2019 12:42 PM PDT

According to studies online, like NCBI, Gabapentin has no activity at GABAA or GABAB receptors of GABA uptake carriers of brain. Also, it doesn't affect GABA transport or metabolism. So, why do so many consider it GABAergic?

submitted by /u/VerlanderFan_23
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How are we able to recognize people at a distance (too far to see facial features)?

Posted: 25 Aug 2019 02:58 AM PDT

So I've noticed that most people can recognize someone they know at a distance too far to see facial features. Some have told me they recognized their walk, or posture, or that they just knew and weren't sure how. Can anyone tell me what is going on here, or how we are able to do this?

submitted by /u/ChaosBetta16
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How do stimulants affect your heart rate?

Posted: 25 Aug 2019 04:26 AM PDT

When using Kirchoff's law to analyse circuits (specifically the loop rule), why is it that if the current and the loop direction are travelling in opposite ways it indicates a voltage lift?

Posted: 25 Aug 2019 12:37 AM PDT

In Alzheimer's, what effects do the enlargement of the ventricles have on the brain/CSF?

Posted: 25 Aug 2019 01:14 AM PDT