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Tuesday, April 2, 2019

AskScience AMA Series: Hi! We're Drs. Rebecca Schmidt from UC-Davis, and Cindy Lawler, from the National Institute of Environmental Health Sciences, part of NIH, and we work on how environmental factors can increase risk of Autism Spectrum Disorder. Ask us anything!

AskScience AMA Series: Hi! We're Drs. Rebecca Schmidt from UC-Davis, and Cindy Lawler, from the National Institute of Environmental Health Sciences, part of NIH, and we work on how environmental factors can increase risk of Autism Spectrum Disorder. Ask us anything!


AskScience AMA Series: Hi! We're Drs. Rebecca Schmidt from UC-Davis, and Cindy Lawler, from the National Institute of Environmental Health Sciences, part of NIH, and we work on how environmental factors can increase risk of Autism Spectrum Disorder. Ask us anything!

Posted: 02 Apr 2019 04:00 AM PDT

Today is the 12th annual World Autism Awareness Day. In honor of that, we're here to answer your questions about how our environment can influence risk of developing Autism Spectrum Disorder, or ASD, in our most vulnerable population -- our children.

Autism encompasses a group of complex disorders involving brain development. Autism symptoms appear very early in childhood and include difficulties in social communication as well as restricted patterns of behavior and interests. Once considered rare, current estimates indicate that autism affects about one in 59 children in the United States.

Scientists now know that ASD is most influenced by a combination of genetic and environmental factors. The National Institute of Environmental Health Sciences (NIEHS), part of NIH, supports autism research aimed at understanding how environmental exposures early in life may combine with genetic susceptibility to alter brain development to create the core symptoms of autism. One way we do that is to support researchers, like Dr. Schmidt, on her work focusing on maternal folic acid intake during pregnancy.

Her research has found that maternal folic acid, the synthetic form of folate, is one of the first modifiable factors identified to date with the potential to reduce occurrence of ASD by 40 percent if taken near conception. Folic acid appears to protect against ASD especially in mothers and children who are genetically susceptible to ASD. Further, her provide evidence that folic acid supplements near conception might counter risk associated with gestational environmental contaminant exposures, like pesticides, air pollution, and phthalates.

Her recent work shows that taking prenatal vitamins that contain folic acid in the first month of pregnancy is also associated with reduced recurrence of autism by about half in younger siblings of children with autism who are at higher risk due to shared genetics and environment. She is also looking at potential ways that folic acid might protect against autism. There are many ways the many nutrients in prenatal vitamins could be critical for brain development and could protect mechanistic pathways implicated in autism, such as epigenetics, DNA repair/synthesis, mitochondrial function, oxidative stress, and inflammation. Dr. Schmidt hopes that future research to understand the pathways involved could improve our understanding of autism etiology.

Dr. Schmidt is also helping to lead the NIEHS-funded Markers of Autism Risk in Babies (MARBLES) study, which is a longitudinal study for pregnant women who have a biological child with ASD. The MARBLES study, which began in 2006, investigates possible prenatal and postpartum biological and environmental exposures and risk factors that may contribute to the development of autism.

Ask us anything about Dr. Schmidt's research on folic acid, the MARBLES study, or other NIEHS-funded research on the environmental risk factors of ASD!

Your hosts today are:

  • Rebecca J. Schmidt, Ph.D., assistant professor in the Department of Public Health Sciences and the MIND Institute at UC-Davis. Rebecca enjoys flying small airplanes, paddle boarding, backpacking, and triathlons!

  • Cindy Lawler, Ph.D., chief of the Genes, Environment, and Health Branch in the Division of Extramural Research and Training at NIEHS. Cindy is an avid walker who usually logs more than ten miles each day, and is also well known for her decorated cut-out sugar cookies!

submitted by /u/AskScienceModerator
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Where in your body does your food turn brown?

Posted: 01 Apr 2019 10:59 AM PDT

I know this is maybe a stupid question, but poop is brown, but when you throw up your throw up is just the color of your food. Where does your body make your food brown? (Sorry for my crappy English)

submitted by /u/Ayko03
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As Everest grows about 1cm taller each year, is there a limit to how high it might get?

Posted: 02 Apr 2019 05:14 AM PDT

Do nuclear reactors create Plutonium?

Posted: 02 Apr 2019 06:08 AM PDT

From my understanding, enriched uranium used in reactors has at best 20% U-235 content, while the majority is U-238. Since neutron radiation transmutes U-238 > U-239 and then decay of U-239 > Np-239 > Pu-239 how much plutonium is created by the fission process? And why isn't this radioactive 'waste' used since plutonium is fissile?

submitted by /u/Raiden60
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On a thermodynamic level, how is it possible that both nuclear fusion and fission release energy?

Posted: 01 Apr 2019 11:44 PM PDT

I know fission involves splitting atomic nuclei. Splitting a larger nucleus into smaller nuclei I think would be entropically favorable and would have a negative deltaG. So it follows that fission would release energy. Following that logic in reverse would imply fusion would not release energy at all and actually be endothermic. This is obviously not true but I'm wondering why.

submitted by /u/pswjt1
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Do flowers produce pollen when they're not planted, i.e. if they're in water in a vase?

Posted: 02 Apr 2019 05:07 AM PDT

Someone at work whose mum is a florist was saying she bitches about people in her shop complaining of hayfever-like symptoms, as apparently flowers not planted don't produce pollen. I have a feeling that this is bullshit but I can't find anything online in my own searching.

Thanks

submitted by /u/FloopersRetreat
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Has the structure of an atom's nucleus been proven?

Posted: 02 Apr 2019 01:54 AM PDT

I've seen in textbooks that the nucleus of an atom looks like several sphere compacted into a bigger sphere, or whatever. My thoughts are that this would have minute effects on how the nucleus affects the atom as a whole from atom to atom of the same element. Is this real? Do two atoms of the same element with different proton and neutron arrangements have miniscule differences in behavior? Or, does the arrangement not exist and it's more like some kind of 'energy soup' or light show?

submitted by /u/anyusernameworks12
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Does a star fuse the iron at the end of it's life?

Posted: 02 Apr 2019 06:31 AM PDT

So this was a lot harder to find out than i thought. People write it so loosely.

They say when a star fuse silicon into iron its going to "die"/go supernova, and it cant fuse iron because it takes to much energy. So fusion stops and it implodes because it does not have that pressure of fusing.

Other say when it starts to fuse iron it require more energy than it gives off, and so its going to loose energy and "die"/go supernova

so in general does it actually fuse some of the iron or does it stop at the silicon to iron and it does NOT fuse the iron?.

I know that it takes a lot of energy to fuse iron, and that iron is at the top of the "binding energy curve" so it does not give of more energy if fused.

and that it makes heavier elements when it goes supernova, its just this "little" detail.

submitted by /u/Staggy123
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Why don't nucleic acids precipitate during Slating-out extrations?

Posted: 02 Apr 2019 06:25 AM PDT

*Salting-out

I understand that the process precipitates proteins by interecting with their charges and making them "less soluble", but how is DNA "protected" from this?

submitted by /u/Roxicaro
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What happens to a neutron star as it loses energy?

Posted: 01 Apr 2019 04:52 PM PDT

So a neutron star has oviously a finite amount of available energy, like any other star. I'm expecting it will cool down over a very long time, but then what? Will it undergo an explosion, like a red giant turning into a white dwarf? Will it just cool down, like a white dwarf turning into a black dwarf? If a neutron star has no longer sufficient energy to glow, what would it look like to a human observer, if it was lit by the light of a star like our Sun?

submitted by /u/VirtualDeliverance
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Why do stars flicker in the night sky?

Posted: 01 Apr 2019 07:21 PM PDT

What would happen if it was possible to split a proton using a quark?

Posted: 01 Apr 2019 02:56 PM PDT

I'd like to preface by saying I'm extremely new to splitting atoms and the technology behind it.

I've been doing some research into nuclear energy and I think I understand the very basic concept of a neutron is fired at an atom which causes a chain reaction of the atom continuously splitting which creates energy.

I know that inside protons are quarks, not too familiar with those but I'm learning. My question is if we could capture quarks and fire them at a proton would that create the same amount of energy, or any energy at all?

submitted by /u/redslayer
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How did we find out what's at the center of the Earth?

Posted: 01 Apr 2019 06:22 PM PDT

Dumb question, but obviously we never reached the center, yet we the core is made of metal. How did we find this out?

And the center of the Earth can also reach incredibly high temperatures. Why is it so hot in the center? Is it mainly due to magma or is there another factor?

submitted by /u/Pakmanjosh
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Do beavers reuse old dams/nests?

Posted: 01 Apr 2019 04:36 PM PDT

Are there any planets that don’t orbit a star?

Posted: 01 Apr 2019 02:44 PM PDT

Quick history of astronauts countering Van Allen radiation belts?

Posted: 01 Apr 2019 10:40 PM PDT

I vaguely remember being told that the first astro(and kozmo)nauts didnt know or care about the Van Allen radiation belts, and that they got stupidly lucky surviving pasing trough them. Is this true, and when did space agencies started protecting astronauts from radiation? I would be very gratefull for a answer, or a link to a very simple article/video on the subject.

I did try googling the answer myself, before bothering you lovely smart people. But all the search results for Van Allen belts are 1 short wiki article and 700 000 MOON LANDING HOAX ILLUMINATI DONT WANT YOU TO KNOW THE TRUTH ABOUT ATLANTIS LEVITATION!!!!!!

Im afraid that if I look at that search page any longer I might get brain cancer, so please save me from cancer.

submitted by /u/Lor360
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Electric field lines in classical electromagnetism?

Posted: 01 Apr 2019 11:21 AM PDT

This may be a dumb question for most people here, but this has been bothering me for awhile, and I am just a layman. Positive charges have lines "pointing away" from the charge while negative charges have lines "pointing toward" the charges.

Other than it's the "direction of the electric field," I don't know what the lines actually represent, and I don't know what the electric field actually is, but it looks like positive charges emit unlimited electric energy for as long as the charges exist, and negative charges consume unlimited electric energy. But unless I am missing something, electrons and photons have finite energy.

Any help appreciated. Thanks.

submitted by /u/DramaticRadish
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Question About Carbon Dating: How Do We Know Prehistoric Levels of Carbon 14?

Posted: 01 Apr 2019 10:28 AM PDT

Hey all! I've been reading about radio carbon dating and I think I understand the basics. Carbon comes in two stable isotopes and an unstable isotope, Carbon 14. Carbon 14 is created in the atmosphere and eventually finds its way into the food cycle and into our bodies. We date things by looking at the percentage of Carbon 14 that is left in remains.

What I don't understand is how do we know that the amount of Carbon 14 that was around 20k years ago is similar to what we have today? Hypothetically, say I die today and my body has 10% Carbon 14 and 90% stable Carbon. From what I understand, and in basic terms, in ~5k years my remains would have 5% Carbon 14 and 95% stable Carbon.

So what evidence is there that 20k years ago there were similar levels of Carbon 14 in living organisms? What if, 20k years ago the atmosphere wasn't producing as much C14 and something died containing only 1% C14 and 99% stable carbon? We find it today and it only has 1/16th of the 1% of C14 and we assume its age is much older?

I'm sure there is a way we can tell, but I was just curious. Let me know if I'm misunderstanding anything or if my question needs more information! Thanks!

submitted by /u/notalltogetherhere
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Why can hyperventilating cause lethal changes in pH?

Posted: 01 Apr 2019 11:01 AM PDT

Do we have any of the same cells from when we were born or have we virtually replaced ourselves?

Posted: 01 Apr 2019 07:44 AM PDT

Monday, April 1, 2019

Why are the Great Basin, Mohave and Sonoran Deserts considered distinct?

Why are the Great Basin, Mohave and Sonoran Deserts considered distinct?


Why are the Great Basin, Mohave and Sonoran Deserts considered distinct?

Posted: 31 Mar 2019 06:27 PM PDT

Looking at a map, these three deserts look like they are right next to each other. Why wouldn't they be known as one big desert?

submitted by /u/sirxez
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Excess Leptin, is that a thing?

Posted: 31 Mar 2019 07:27 AM PDT

Since Leptin deficiency is a thing, often leading towards obesity, where you're essentially always hungry, is there a situation, where, naturally, you'd have excess leptin? I know of the feedback loop where if you don't eat much, you get reduced leptin and always be hungry, and if you eat too much, you produce more leptin to signal that you're satiated.

Would there be a situation where, like leptin-deficient people, you'd have natural excess leptin, and never really be hungry? Is there any correlation between this and anorexia? There is definitely a correlation between not enough leptin and eating too much, but is there one for the opposite?

submitted by /u/phermyk
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What are the long term consequences of plastic in the oceans?

Posted: 01 Apr 2019 06:23 AM PDT

I know little to nothing. Big plastic is not what I am talking about but the micro plastics.

I have read that the real bad plastic comes from clothes in the form of micro particles that are eaten by plankton.

This started in the 50s or something, don't believe me on the date, and today there is not much we can do to reverse this.

What are the effects of plastic in living things? to they go in and out? does plastic makes living things sick?

If most plankton (hypothetically) is full with plastic and the whole ocean food chain gets plastic, will we too? and again, long term consequences.

submitted by /u/One_Cold_Turkey
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Do sounds sound different at higher altitudes?

Posted: 01 Apr 2019 06:04 AM PDT

If you make a sound wave at a higher altitude where the density of air is a lot lower, does that for instance, change the pitch of the sound? (compared to at sea level)

submitted by /u/Babaguscooties
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Why is the speed of sound significant with regard to aerodynamics?

Posted: 01 Apr 2019 04:41 AM PDT

Why does the speed of a sound wave through air have any relationship or bearing on a completely different type of object moving through the same medium at the same speed?

submitted by /u/buddhahat
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Do deciduous plants grow new leaves from the exact spots where the old leaves fell? Or only from new growth in the last year?

Posted: 01 Apr 2019 07:09 AM PDT

[Cross-posted from r/botany] I hope I can explain my question well enough to get an answer!

From what I understand, leaves and new stems only grow from nodes on a stem. The type of plant determines whether one or more leaves will grow per node, and those leaves grow as soon as the node is created, along with an axillary bud. The axillary bud might 'wait' a long time but at any point it may start growing a new stem (not a single leaf). Am I right so far?

So, how does all this relate to deciduous plants that lose their leaves? Once a particular node has lost its leaf/ves, will it grow new leaves from the same node in the following spring? Does the axillary bud become a leaf bud instead of a stem? If so, what happens when that leaf is dropped in the year after that - is another new bud produced?

Or are new leaves only produced at new nodes? If that's the case, how does the tree produce enough new stem growth that one years' worth of new nodes can grow enough leaves to support the entire tree? At what point in the growth season do new nodes stop making new leaves and decide to 'wait' until the following spring?

submitted by /u/noibs
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What's the difference between acidosis and alcohol intoxication?

Posted: 01 Apr 2019 07:21 AM PDT

Both have very similar side effects so I'm wondering what is the difference and are they related in any sort of way. Need more of a chemistry answer rather than a biology one

submitted by /u/ipatman28
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Did the atomic bombs dropped on Hiroshima and Nagasaki have any effect on weather patterns? Either in the short term or long term? Close proximity or worldwide?

Posted: 31 Mar 2019 09:23 PM PDT

How are oasis’ formed and survive?

Posted: 31 Mar 2019 07:08 PM PDT

Where does the water come from and how does it not just evaporate?

submitted by /u/annalueb
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How accurate are the sounds of planets that NASA manages to record?

Posted: 01 Apr 2019 05:03 AM PDT

Do overweight people have extra amount of nerves and pain receptors distributed around their body?

Posted: 01 Apr 2019 07:26 AM PDT

I always thought the amount of nerves and pain receptors is fixed regardless the size you are, and the bigger your are, the less nerves density you have, which should make you less sensitive and more resistance to pressure pain. However a study: "Body mass index and distribution of body fat can influence sensory detection and pain sensitivity" I ran into suggested the opposite.
Do overweight people grow "extra" amount of nerves to cover their bigger surface area?

submitted by /u/5210az
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Would it be possible to preserve a brain?

Posted: 01 Apr 2019 01:23 AM PDT

As the title already says; I wonder if it would be possible to preserve a brain by connecting it to an artificial heart (ofcourse with nutrients).
I don't think it would be possible but I can't think of a reason why not but there sure is a very simple explanation.

I hope you guys can help me figure this one out.

Thanks in advance.

submitted by /u/newlander007
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How are sheer drop cliffs created?

Posted: 31 Mar 2019 09:59 PM PDT

I know that a lot of it deals with erosion and plates but what are the specific circumstances needed to form a sheer cliff?

submitted by /u/Black313x
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If you die from an allergic reaction do the resulting physical symptoms such as hives or swelling remain after death?

Posted: 01 Apr 2019 06:17 AM PDT

Let's say I was deathly allergic to something such as a bee sting. If I got stung and broke out in hives and my face swelled up and then I later died without the hives and swelling clearing up, would those hives and swelling remain? Or would do the reactions clear up after death?

submitted by /u/Akuba55
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Why are the colors of a rainbow always in the same order?

Posted: 01 Apr 2019 05:02 AM PDT

How do flies maintain visual accuracy and a sense of surrounding at such high speeds of movement?

Posted: 31 Mar 2019 10:37 PM PDT

How do scientists discover new species?

Posted: 31 Mar 2019 10:34 PM PDT

Do scientist go to the field and discover new species by luck or do they have a systematic/efficient way of searching?

submitted by /u/On9999
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Is there a limit on the "brightness" a typical fiber optic cable can carry?

Posted: 31 Mar 2019 06:47 PM PDT

I want to give an example of what I mean:

Supposing you are living underground, but you can't just make a hole in the ceiling to get sunlight, can you use fiber optic cable to catch the sunlight on the surface and redirect it to your underground home ? And if yes, will you be able to tell the difference ?

submitted by /u/Exymat
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Are there any organisms that don’t need carbon dioxide or oxygen to survive?

Posted: 31 Mar 2019 05:36 PM PDT

Do other kinds of waves “break” like waves of water in the ocean?

Posted: 31 Mar 2019 02:15 PM PDT

Seeing a slo-mo of a wave breaking inspired this question. Waves of water can break, especially when they near the shore, and the water in the wave comes tumbling down over/in front of it. Is this process physically possible with any other waves in any other medium, or unique to the mass of water, speed and frequency of ocean waves, etc.?

submitted by /u/simplysalamander
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How does the malfunction of a peptidase cause accumulation of lipid pigments in Neuronal Ceroid Lipofuscinosis?

Posted: 01 Apr 2019 01:58 AM PDT

So first off a disclaimer: Yes, this overly specific question did arise because of an assignment, however the assignment itself is about a treatment and is not focused on understanding of the disease. I can complete the assignment without this knowledge, but my sources all agree on the cause and the symptoms while I can't wrap my head around how they are specifically related. I'm hoping to catch an expert here since my teacher is not an expert on this disease. I hope the mods will keep this up.

Late Infantile Neuronal Ceroid Lipofuscinosis (LINCL) is caused by a mutation in the CLN2 gene, causing a defect in the enzyme tripeptylpeptidase1 (TPP1). This enzyme cleaves tripeptides from the N-terminus of the target protein with no known substrate specificity. The defect in this enzyme causes lysosomal accumulation of lipofuscins, lipid containing pigments. From the structures I found lipofuscins do not contain peptide bonds, so they shouldn't be cleaved by TPP1.

Now my question: How are these two related? There seems to be a consensus on the cause and effect of the disease, but I don't get how a defect peptidase can cause an accumulation of lipids.

submitted by /u/Magisidae
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How does electric shock kill you?

Posted: 31 Mar 2019 09:25 PM PDT

How does electrocution kill a person? Does it literally cook your brain? Does it constrict your heart forcing it to stop? Do we even know exactly how it kills you?

Also: not sure what flair to add to this. Medicine is the only thing I can think of that would relate to it.

submitted by /u/paytonimore
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Sunday, March 31, 2019

Are any unique properties expected to arise as matter gets even closer to absolute zero?

Are any unique properties expected to arise as matter gets even closer to absolute zero?


Are any unique properties expected to arise as matter gets even closer to absolute zero?

Posted: 30 Mar 2019 06:48 PM PDT

I am aware that many unique properties arise as things become very cold, but there seem to be a lot of efforts seeking to make matter as close to absolute zero as possible.

Is this just an engineering demonstration, or do we expect different properties to emerge when something is, for example, 10E-15 kelvin versus 10E-10 kelvin?

submitted by /u/LiqiudIlk
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What climate change models are currently available for use, and how small of a regional scale can they go down to?

Posted: 30 Mar 2019 09:30 AM PDT

I want to see how climate change will affect the temperature and humidity of my area in 25 years.

How fine-tuned are the current maps for predicted regional changes?

Are there any models that let you feed in weather data (from a local airport for example) and get out predicted changes?

Are there any that would let me feed in temperature and humidity readings from my backyard and get super fine scale predictions?

The reason I'm asking is because I want to if my area will be able to support certain crops in 25 years. I want to match up the conditions of my spot 25 years from now with the conditions of where that crop is grown currently.

Edit: I've gotten a lot of great replies but they all require some thought and reading. I won't be able to reply to everyone but I wanted to thank this great community for all the info

submitted by /u/fortylightbulbs
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Are there any species which more or less completely die off every generation and rely on eggs to survive without the parents to continue the species?

Posted: 30 Mar 2019 07:08 PM PDT

I thought about this today and thought it was an interesting concept. My first thought was that it seems entirely possible that an entire species of insect could almost entirely die off in the winter amd only survive due to eggs stored underground. Am I being dumb? Is this possible? Does such a species exist?

submitted by /u/Nowhere_Man_Forever
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Why are the Galapagos Islands specifically so important to study?

Posted: 30 Mar 2019 05:46 PM PDT

I always see the Galapagos Islands as the big place that people are studying. I realize there are major historical discoveries that have happened there, but aren't there likely to be many archipelagos that are near a mainland that display the same amounts of natural selection and adaptive radiation? Are they just the "famous" archipelago? Is there a really unique situation there? Or are people building upon 100+ years of research in that specific place?

submitted by /u/thinkofagoodnamedude
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Is the current number of human beings alive higher or lower than the number of humans that have died?

Posted: 30 Mar 2019 09:24 AM PDT

I don't know how to properly phrase this question so bare with me.

In an exercise about problem solving techniques this question arose.

Is the number of current human beings alive higher or lower than the total number of humans that have died since the human race exist (or some early point in history)? It's hard to define the boundaries but let's say we base our case in registered or estimated child mortality, perhaps?

Of course it's a highly speculative question but id love to know if someone approached this matter before, and how.

Thanks.

submitted by /u/lordroderick
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Is the ability to recall something from memory effected by how awake you were when you learned it?

Posted: 30 Mar 2019 06:13 PM PDT

If I am studying and it is late at night and I'm tired, when I am fully rested how will my ability to remember what I was learning be effected.

I work shifts and often do study for a few hours between 10pm and 1am. I was wondering if this is a poor way of learning.

submitted by /u/Tom-tron
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What parts of human vision are innate vs learnt?

Posted: 30 Mar 2019 04:43 PM PDT

How much of the human vision ability are we innately born with and what parts do we learn? I understand that human vision is a broad area so its hard to list all features that we innately have vs learn and I also understand that we don't fully understand how the human vision process fully works yet. But I am hoping for some insight into what elements of human vision we learn.

It may be easier to answer specific questions, so...

  • We know that edge detection is performed. Is this innate or learned?
  • We know that we place higher precedence/value on areas around edges vs homogenous areas for eg; on a blank white wall our eyes are drawn to the wall edges vs the wall centre. Do we know if this is learnt or innate?
  • Obviously object detection (chairs, etc.) is learnt but what about object boundaries and association? For example a chair is made up of 4 legs, a back and seat do we innately know these 3 aspects are all associated/grouped together or do we learn this? Do we use depth/stereopsis to associate sub-objects?
submitted by /u/sqzr2
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Could a Geologist Please Help Explain Limestone Layering?

Posted: 30 Mar 2019 09:25 PM PDT

Thanks for helping out a lay person who is a geology enthusiast.

What causes the abrupt and distinct color and texture differences in midwestern limestone bluffs? I understand that oceans laid down the layers. The questions are:

  • What climate or ocean changes caused the different coloring?
  • What changed in the ocean to make the layers so sharply distinct and different? Even the fossils change abruptly, from many to none.

It seems to imply some big changes must have happened fast for laying to be so varied and distinct.

Thanks again

submitted by /u/Emwonk2
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Relative to humans, snakes outer epithelial layer sheds much different than ours. I understand the human epidermis from human anatomy and was hoping someone could explain this process for a snake in which the outer layer all disconnects at once to shed a complete skin of the snake?

Posted: 30 Mar 2019 05:09 PM PDT

Are vitamins more effective if you know what they do?

Posted: 30 Mar 2019 02:38 PM PDT

Essentially; does the placebo effect strengthen the effectiveness of vitamins? Especially since we know the vitamins are regulated and not sugar pills.

submitted by /u/BroodPlatypus
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Why do fruits get sweeter the longer you wait?

Posted: 30 Mar 2019 05:54 AM PDT

How much does the centrifugal force of the earth’s rotation counteract gravity at the surface? If the earth wasn’t rotating, how heavy would a kilogram be at sea level?

Posted: 30 Mar 2019 03:54 PM PDT

I was reading about how the Gault asteroid is spinning so fast the surface material overcomes gravity and escapes. This made me wonder about the earth's rotation and how much centrifugal force is acting against the earth's own gravity. Would it make any measurable difference if there was no rotation? Would it be so much that we'd all be squashed by our own weight?

submitted by /u/obijohn
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Is the global polar bear population increasing, or decreasing? There are a bunch of articles on either side, including fact-checks. Not looking for political stuff.

Posted: 30 Mar 2019 07:42 AM PDT

Does the act of actively recalling old memories provide any physical benefits to the brain?

Posted: 30 Mar 2019 10:15 AM PDT

Also, could it provide similar benefits as meditation?

submitted by /u/Battlejew420
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We have geological and fossil evidence of the fluctuation in the ratio of gasses in the atmosphere 100’s of Ma back. What evidence do we have about fluctuations in atmospheric pressure?

Posted: 30 Mar 2019 01:48 PM PDT

Looking at the other planets in our solar system, particularly Venus, it is clear that the amount of atmosphere on a terrestrial planet is not dictated by gravity alone. And in the case of Mars we are fairly confident it can fluctuate by quite a bit over the life of a planet. Do we know if Earth's atmospheric pressure has changed substantially over its history? More specifically, how it has changed during the period of complex life?

submitted by /u/Prosodism
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It is said that universes is always expanding but expanding onto what?

Posted: 30 Mar 2019 07:19 AM PDT

Like what's after the edge of our universe🤔🤔

submitted by /u/Astro_11
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If you chip your bone from an injury, what happens to it?

Posted: 30 Mar 2019 04:35 AM PDT

What does a choloroplast actually need to survive?

Posted: 30 Mar 2019 08:19 AM PDT

If I remember correctly, Choloroplasts are sort of autonomous "cells", trapped inside plat cells, reproducing on their own account. What do they actually need to live, what do they produce (atp i assume) and what do they need to produce that?

submitted by /u/Plagiatus
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Can the Stern–Gerlach experiment measure spin direction?

Posted: 30 Mar 2019 11:56 AM PDT

As I understand, it just proves that spin is quantized and it can also measure the spin of individual particles, but not the direction of them. Is this true? Furthermore, if it can, how would differently facing spins appear in the output of the experiment?

On a side note, mildly related to the main question: does a beam of positrons generated from pair production, separated from the electrons, have all their spins facing in the same direction?

Thanks for the answers in advance!

submitted by /u/fostmester69
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How does slime mold navigation differ from an ant colony finding food?

Posted: 30 Mar 2019 08:46 AM PDT

I recently found these visualizations of physarum polycephalum and a short explanation, along with Wikipedia's summary. While obviously there are a million unanswered questions about how it works, it seems like at a basic level the mold's behavior is similar to an ant colony - spread out randomly and reinforce paths that lead to food. Having dealt with SIX ant intrusions recently, the biggest difference I noted is that ants seem somewhat less concerned with the shortest path. What are the other similarities and differences?

submitted by /u/AppleGuySnake
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is spaced repetition learning scientifically accepted and how does it work?

Posted: 30 Mar 2019 10:01 AM PDT

Can you be/get immune to any kond of anaesthetic?

Posted: 30 Mar 2019 01:15 PM PDT

If so, how will they be treated

submitted by /u/djbezza
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