Pages

Sunday, September 29, 2019

Do we know about any objects that travel at large fractions of the speed of light?

Do we know about any objects that travel at large fractions of the speed of light?


Do we know about any objects that travel at large fractions of the speed of light?

Posted: 28 Sep 2019 06:03 PM PDT

We know that many particles travel at the speed of light, and sometimes I hear descriptions such as "these particle travel at roughly 0.5% of the speed of light" (paraphrasing, obviously). Do we know of any particles or phenomena that travel at, say. 50% of the speed of light, or some significant fraction?

submitted by /u/OLTARZEWSKT1
[link] [comments]

Why have CPU clock speeds stopped going up?

Posted: 29 Sep 2019 07:06 AM PDT

You'd think 5+GHz CPUs would be everywhere by now.

submitted by /u/jjake101
[link] [comments]

How do quantum dots (>20nm) absorve and release vidible light (<400nm) if they are smaller than the visible light wavelength?

Posted: 28 Sep 2019 06:46 PM PDT

Actually as I'm writing this question I also don't understand how we see materials, we do obviously see them but the atoms are smaller than the wavelength we see, so what is happening?

Can atoms emit wavelengths bigger than their size? How?

Or do we just see the cristaline structure of a bunch of atoms?

submitted by /u/mrBatata
[link] [comments]

Since HIV-infected patients have such high levels of antibodies, how does the virus make progress at all?

Posted: 28 Sep 2019 08:21 PM PDT

My understanding of how HIV progresses is something like this (please correct me if I get something wrong):

Shortly after infection, patients experience flu-like symptoms for a few weeks. They feel better after that time because their body has produced a sufficient number of antibodies to prevent the virus from killing them. Untreated patients then feel fine for a long period of time (years or even decades) before developing opportunistic infections resulting from AIDS. These infections usually kill the patient within a few years.

My question is this: given that the human body seems to be capable of preventing the virus from destroying its host's immune system for several years, how does the virus make any progress? Why do the HIV-specific antibodies slow down the progression of the disease, but not stop it?

(Side note: With most viruses I'm familiar with, either the virus is eliminated or the host dies from the infection, with the main exception I can think of being the herpes virus. Does herpes stick around in the body for similar reasons? Or is this just a coincidence?)

submitted by /u/BrainEnema
[link] [comments]

Is sexual orientation defined by genes? If so, how does it affect twins? If one of them is, say, homosexual, will the other be homosexual too?

Posted: 28 Sep 2019 07:13 PM PDT

What is so unique with HCl, why does it seems so versatile?

Posted: 28 Sep 2019 07:03 PM PDT

I use to just stereotype HCl (Hydrocholirde) as a cleaning agent (bleach) but recently came across to a lot of HCl derivatives especially in meds (Meperidine HCl, Isoxsuprine HCl, Hydralazine HCl to name a few)

How exactly does this work? What is with HCl?

submitted by /u/Zephynx4476
[link] [comments]

How does Google know ‘what I mean’ when I misspell a word?

Posted: 28 Sep 2019 05:23 PM PDT

When testing rocket engines how are the engines secured so they don’t go flying off?

Posted: 28 Sep 2019 08:39 PM PDT

Whenever I see a video of a rocket engine being tested it's horizontal to the ground. How do they attach something that generates that much force/thrust to the ground so that it doesn't break the connection or fly off?

submitted by /u/bmh55
[link] [comments]

Would traveling with a shockwave at the speed of sound do more damage to your vehicule/yourself than if it went through you?

Posted: 28 Sep 2019 07:42 PM PDT

I've been wondering about this for a while and can't find a proper answer. Sorry if I'm in the wronf subreddit!

submitted by /u/Zielko
[link] [comments]

What is stopping us from building gamma microscopes?

Posted: 28 Sep 2019 06:07 PM PDT

They would have higher resolution than electron microscopes, which may give further gains in science.

I was also wondering if they would be able to see atoms.

submitted by /u/JoeyBobBillie
[link] [comments]

Why does ice taste different to water?

Posted: 28 Sep 2019 07:54 PM PDT

This includes water that has just melted from ice. It has a very specific and recognisable ice-taste.

submitted by /u/tribalbaboon
[link] [comments]

Do Palm Trees of All Varieties Have Long Strandy Leaves Because They Survive Tropical Storms Better?

Posted: 28 Sep 2019 07:12 PM PDT

Do Palm trees and other plants with similar leaves (and a strange lack of branches) actually survive tropical storms better than plants like oaks or maples whose leaves are more likely to catch wind and fall over? Or is it a coincidence?

submitted by /u/jim10040
[link] [comments]

How strong is the pull of the Vacuum of Space?

Posted: 28 Sep 2019 07:07 PM PDT

A common cliche I've seen in space stories is the event of a breech in a ship's hull that leads to the empty vacuum of space and people have to hold on or get pulled through. My question is: How strong IS this pull? I feel it would be much stronger than what a normal human can resist with their bare hands. Does the size of a hole effect the pull or is it all the same pull? I would like to know the actual pull strength (if that's even measurable) of space's vacuum.

EDIT

As some people have pointed out, my use of the word "pull" should be "suction," as a vacuum doesn't pull so much as suck air out, which is what a person must fight to resist being sucked out into space. Also, in the question of pressure and air, it would say the conditions are identical as that found on the International Space Station.

submitted by /u/UndeadPriest94
[link] [comments]

Can pregnancy hormones make straight hair curly or curly hair straight - all the way to long ends and not just the new growth?

Posted: 28 Sep 2019 07:01 PM PDT

I have been told and have also read many times that this is a possibility. But here is my problem with a blanket statement like that coming from a parenting article or my hair dresser: I understand that lots of things can change the shape of the hair follicle, which in turn changes the texture and curl pattern of the hair shaft. However, if a person already has longer hair ( mine, for example, is a few inches past my shoulders) I cannot understand how the shift in hormones under a less than one year time span, can affect the shape and texture of the hair shaft all the way to the bottom. New growth, yes. I can understand that. But now at 7 months pregnant, my hair is very wavy (about a 2B on the curl pattern chart) and is a shock to me and others who know me. But my thought is that it must have been leaning towards wanting to be wavy for years and I've only just decided to start encouraging the process and therefore, it has now seemingly sprung in to curls. Or, since the beginning of this pregnancy, the hormones have caused a shift in the shape of my hair follicle, therefore increasing the curl tendency in my new growth, which is helping to support the wave tendency in the rest of my long hair.

Is it possible for hormones to change curl structure all the way to the ends of hair which could have been growing for multiple years, and couldn't be affected by a hormonal change at the scalp in a short time period?

This is the most scientific article I could find on the topic, and it doesn't address the idea of long hair, just need growth from the follicle.

https://www.scienceworld.ca/blog/can-hair-change-straight-curly

submitted by /u/BesmirchedAnatexis
[link] [comments]

Does each unique action (moving an arm, moving a leg, breathing) correspond to a unique brainwave?

Posted: 28 Sep 2019 06:58 PM PDT

Or is it more like, he is moving a limb type specific?

submitted by /u/IanGuard7000
[link] [comments]

Is c÷(average wavelength) the same as the (average frequency) of a spectrum?

Posted: 28 Sep 2019 01:00 PM PDT

So, I'm having a little trouble here. I want to know the average energy of the photons emitted by a LED. What I have is the graph of intensity by wavelength.

I know that each point in the graph is actually the intensity integrated over a small interval near that point (analogous to a displacement vs time graph where each point is the displacement during a small time interval around that time).

But say that instead of that I had an actual continuous power distribution function, a graph now analogous to a velocity vs time graph. I must integrate the function over an interval of λ to find the intensity on that interval.

I'll call that function i(λ) (lowercase 'i' because that's not an intensity now but rather a "density")

I want to convert it to a function i(f) in such a way that the integrated intensity over an equivalent interval is the same, in other words

i(f)df = i(λ)dλ

Once f = c/λ -> df = (-c/λ²)dλ -> i(f)*(-c/λ²)dλ = i(λ)dλ -> i(f) = -(λ²/c)i(λ)

So I might choose i(λ) = kλ for example. 'k' is a constant that will deal with the units. And I might choose an λ interval from a to b meters. The integral of i(λ) will be (k/2)(b²-a²)

The frequency-domain function will be i(f) = -kλ³/c = -kc²/f³

The primitive integral of of that function is (kc²/2)/f² + C. Integrating from c/a to c/b (the equivalent interval in the frequency domain) the the result is (kc²/2)*[1/(c/b)²-1/(c/a)²]= (kc²/2)*[b²-a²]/c²
= (k/2)(b²-a²)

This is the same result and shows that the the power distributions check - They give the same total intensity for the same interval. Being that, obviously, each function have different units once they have different domains, but the units of the integrated intensity will be the same.

Now for the average value of wavelength and frequency:

i(λ)*λ = kλ² -> integral over the interval a to b = (k/3)(b³-a³)

dividing by the integral intensity we have (k/3)(b²-a²)/[(k/2)(b³-a³)] -> λ(av) = (2/3)(b³-a³)/(b²-a²)

i(f)*f = -kc²/f² -> integral over the interval of c/a to c/b = kc(b-a)

dividing by the integral intensity we have kc(b-a) /[(k/2)(b³-a³)] -> f(av) = 2c(b-a)(b²-a²)

If I took λ(av) and found the equivalent frequency, I'd have c/λ(av) = c(3/2)(b²-a²)/(b³-a³), which is not the same as 2c(b-a)(b²-a²)

For example, choosing a=100 m and b=300 m ->
λ(av) = (650/3) m,
c/λ(av) = 1383657.50 Hz, and
f(av) = 1498962.29 Hz.

They are reasonably close to each other but not equal

Is that how it should be?

submitted by /u/guferr
[link] [comments]

Can we send radio signals at a fast enough speed or frequency so that they are in the visible light spectrum?

Posted: 28 Sep 2019 06:54 PM PDT

Have any studies tried to find correlation between heigh and average sunlight exposure?

Posted: 28 Sep 2019 06:13 PM PDT

I wondered if one exposed to more sunljght than a group with below average exposure, controlling for nutrition, in the ages of 14-18 would have found larger vertical growth over time, and potentially the ratio of sunlight to growth.

Vitamin D could be isolated for experimentation on height because currently the largest propagandist source for it is that it's from 'genetics' or DNA with no real credible sources viably identified as being the main source.

Thank you.

submitted by /u/WeAreElectricity
[link] [comments]

Does schizophrenia alter the brain physically?

Posted: 28 Sep 2019 05:34 PM PDT

I'm thinking something along the lines of Alzheimer's or any other sort of neuro-degenerative disease. Does schizophrenia have any physical impact on the brain?

submitted by /u/YER_MAW_IS_A_ROASTER
[link] [comments]

How does a stem cell transplant help with HIV treatment?

Posted: 28 Sep 2019 08:02 PM PDT

I heard that two patients were cured of HIV after radiotherapy and a stem cell transplant using a donor's stem cells? How does that cure the HIV? Could they have used their own stem cells rather than a donor?

submitted by /u/AverageVancouverite
[link] [comments]

Is E. coli Turing complete?

Posted: 28 Sep 2019 07:39 PM PDT

Saturday, September 28, 2019

AskScience AMA Series: I'm Kit Yates. I'm here to talk about my new book, the Maths of Life and Death which is about the places maths can have an impact in people's everyday lives. I'd also love to discuss my research area of Mathematical Biology. Ask Me Anything!

AskScience AMA Series: I'm Kit Yates. I'm here to talk about my new book, the Maths of Life and Death which is about the places maths can have an impact in people's everyday lives. I'd also love to discuss my research area of Mathematical Biology. Ask Me Anything!


AskScience AMA Series: I'm Kit Yates. I'm here to talk about my new book, the Maths of Life and Death which is about the places maths can have an impact in people's everyday lives. I'd also love to discuss my research area of Mathematical Biology. Ask Me Anything!

Posted: 28 Sep 2019 04:00 AM PDT

Hi Reddit, I am Kit Yates. I'm a senior lecturer in Mathematical Biology at the University of Bath. I'm here to dispel some rumours about my fascinating subject area and demonstrate how maths is becoming an increasingly important tool in our fight to understand biological processes in the real world.

I've also just published a new popular maths book called the Math(s) of Life and Death which is out in the UK and available to pre-order in the US. In the book I explore the true stories of life-changing events in which the application (or misapplication) of mathematics has played a critical role: patients crippled by faulty genes and entrepreneurs bankrupt by faulty algorithms; innocent victims of miscarriages of justice and the unwitting victims of software glitches. I follow stories of investors who have lost fortunes and parents who have lost children, all because of mathematical misunderstanding. I wrestle with ethical dilemmas from screening to statistical subterfuge and examine pertinent societal issues such as political referenda, disease prevention, criminal justice and artificial intelligence. I show that mathematics has something profound or significant to say on all of these subjects, and more.

On a personal note I'm from Manchester, UK, so it's almost a pre-requisite that I love football (Manchester City) and Music (Oasis were my favourite band). I also have two young kids, so they keep me busy outside of work. My website for both research and pop maths is https://kityates.com/

I'll be online from 8-9pm (GMT+1) on Saturday 28th September to answer your questions as part of FUTURES - European Researchers' Night 2019.

submitted by /u/AskScienceModerator
[link] [comments]

How does cocaine get into the hair structure through use and environmental exposure?

Posted: 28 Sep 2019 07:17 AM PDT

I'm reading an article that was published in Analytical Chemistry that discusses the current methodology for forensic hair drug analysis in Europe.

The Society of Hair Testing says that hair samples should be prepped with an organic solvent wash followed by aqueous washes to remove contaminants.

However, a 3-year-old paper discovered that if the hair is somehow contaminated with cocaine (I guess either through lab error or maybe the person goes to places where cocaine particulates/vapor is in the air) the cocaine will permeate throughout the hair and present like user hair.

The authors looked at the cross-section of hair with a MetA-SIMS (TRIFT II TOF-SIMS) and compared it with conventional methods (LC-MS/MS). The contamination wasn't removed in the washes with organic solvents and water according to the LC-MS/MS, it permeated throughout the hair according to the TOF-SIMS.

I'm trying to figure out 2 things. One: How does cocaine chemically enter the hair if you're a user? Two: If cocaine hydrochloride (cocaine a rich person might buy) is water soluble, why isn't it coming out in the water? Why is permeating the hair further? (However this is also true for cocaine base, or "crack" cocaine. Though I'm having issues determining solubility with crack cocaine.)

FWIW, hair is composed of mostly keratin. Keratin is helical due to hydrogen bondings and has sulfate groups due to cysteine. Hair also has minerals due to diet and water, and contains lipids (cocaine vapor is lipophilic).

I'm finding a lot of speculation online and I was hoping for some more concrete cocaine chemistry. Thanks in advance.

submitted by /u/dumbquestion6669
[link] [comments]

When I sleep with a bad pillow and spend all of the next day with a crick in my neck what has actually happened to cause such a pain in the neck?

Posted: 28 Sep 2019 03:14 AM PDT

Do a greater proportion of people have mental health disorders (diagnosed and undiagnosed) than 50 years ago? All mental health disorders or only some? For all ages groups, genders, countries? If so what is the likely cause, or why is there a perception that it is?

Posted: 27 Sep 2019 10:29 PM PDT

How did heavy metals arrive on Earth during planetary formation?

Posted: 27 Sep 2019 02:24 PM PDT

I understand that most heavy metals are created during supernovae and ejected during the explosion, but I'm not quite understanding as to how so much of anything metallic - especially elements higher in the periodic table - came to be part of the primordial dust cloud - a cloud composed of still so very much hydrogen that plenty of stars could form in our neighbourhood - that we have such a mix of elements here, and likely on any planet?

submitted by /u/JimBobBoBubba
[link] [comments]

Is Language still evolving as fast as before? Or has the evolution of language slowed or sped up with modern globalization and standardization?

Posted: 27 Sep 2019 11:33 AM PDT

I saw a showerthought post about how 1000 years into the future people wouldn't be able to understand you or you them, and the same thread had some posts about how English 1000 years ago is completely incomprehensible to modern English.

I was wondering, with the advent of the Internet+Globalization (so no isolated pockets developing their own unique language because they're still always in touch with the parent language), and the general standardizing of languages via rules for grammar and spelling (rules that weren't really a thing 1000 years ago), what sort of effect has this had on language development?

Is language changing faster than before? Has it slowed? Are any particular languages (French, for example, which is known for strict standards in their language) changing slower than others?

submitted by /u/Athrowawayinmay
[link] [comments]

Why does U-Pb dating have a limit of 500,000 years ago?

Posted: 27 Sep 2019 12:43 PM PDT

My book just says that you can use Uranium-Lead dating for samples that were formed up to 500000 years ago. Why does U-Pb dating have this limit?

submitted by /u/Gengumain02
[link] [comments]

Where did native Americans come from?

Posted: 27 Sep 2019 03:18 PM PDT

If laurasia and gondwana split into the continents millions of years ago and Homo sapiens appeared first in Africa 200,000 years ago how did the red Indians get to America with no advanced ships or means of transport at that time while they were so primitive even at the time when the British got there

submitted by /u/Vonitae
[link] [comments]

What happens to amputated body parts?

Posted: 27 Sep 2019 07:03 AM PDT

If someone needs a whole leg amputated, what is the process that severed leg goes through since its removal? What about other body parts like (for lack of a better example) the foreskin when people get circumcised?

Thanks.

submitted by /u/Brendanmicyd
[link] [comments]

How do people die from severe burn injuries?

Posted: 27 Sep 2019 03:05 PM PDT

I get how you can die if you stay in the fire or axphiliate from the smoke, but what about those who die later in the hospital?

submitted by /u/purpleshep1
[link] [comments]

Does my immunity to certain illnesses from being vaccinated also protect my newborn from the via breastmilk?

Posted: 27 Sep 2019 10:25 PM PDT

Sorry if it's worded weird but with the outbreaks of measles I'm concerned for my newborn, who is obviously too young for the vaccine. Is breastfeeding helpful in preventing her from getting an illness that she must be vaccinated against or is she just in danger until then? Sorry if it's an ignorant question.

submitted by /u/mckat2247
[link] [comments]

Could you cause a dead bodies muscles to contract by electricly shocking them as you would with a living body?

Posted: 27 Sep 2019 04:17 PM PDT

How does improved cardiovascular endurance manifest physically in the body? Does the heart/lungs change at all in the way that a muscle gets larger with strength training?

Posted: 27 Sep 2019 11:01 AM PDT

What exactly is computer hacking? What is going on behind the scenes?

Posted: 27 Sep 2019 05:23 AM PDT

First and foremost: NO I am not asking for a set of directions or a guidebook on how to hack computer systems. But I am curious about what is actually happening behind the scenes when someone hacks a computer, network, or website. What is actually going on?

My only frame of reference would be locks. I am in to locksport and when I try and pick a new lock there is an opening that I can put picks in, feel the pins, and with some luck and patience and time, align the pins and pop the lock open. What is the equivalent in computer terms?

submitted by /u/gdaem
[link] [comments]

Are there any examples of impractical side-effects of evolution?

Posted: 27 Sep 2019 08:39 AM PDT

I remember hearing something about the long stalks of the stalkeyefly. How they were important for males finding a mating partner. They are selected more often as mating partners which leaves their offspring (male or female) with long stalks too, even though the females don't really need them. I doubt this is the best example of what I am looking for, and want to know if there are examples from nature and evolution that "does the job", but is actually a bit of a hindrance for the animal in question.

submitted by /u/Chicken_McFlurry
[link] [comments]

Why do cookies have crumbs?

Posted: 27 Sep 2019 09:59 AM PDT

Why do cookies have crumbs so large you can count them? Is there a reason they aren't small like sand?

submitted by /u/SovietTaters
[link] [comments]

is it true, Lysosomal Storage Disorders happens due to inbreeding in human?

Posted: 27 Sep 2019 09:29 AM PDT

Is it possible to transfer immunity against viruses through bloody transfusion?

Posted: 27 Sep 2019 09:06 AM PDT

Is there a mechanism where immunity can be transferred through bloody transfusion and are there documented cases of this happening?

submitted by /u/sonomodata
[link] [comments]

The United States cited presence of EMPTA in its bombing of the Al-Shifa pharmaceutical plant in Sudan in 1998. Are there any uses for o-ethyl methylphosphonothioic acid other than the production of nerve gas?

Posted: 27 Sep 2019 08:24 AM PDT

Blood donation after death?

Posted: 27 Sep 2019 08:18 AM PDT

Like organ donation, can blood be donated after death? And, if so, what is the period of time after death in which the blood is taken?

submitted by /u/theland_man
[link] [comments]

Are there general patterns to where minerals and ores can be found on Earth?

Posted: 26 Sep 2019 09:46 PM PDT

I ask because I'm doing a speculative worldbuilding project with an Earth-like planet, and I want it to be as realistic as possible. Thanks in advance!

submitted by /u/way-too-much-effort
[link] [comments]

Friday, September 27, 2019

AskScience AMA Series: I'm Dr. John Troyer, Director of the Centre for Death and Society at the University of Bath and I'm here to talk about death, dying, dead bodies, grief & bereavement, and the future of human mortality. Ask Me Anything!

AskScience AMA Series: I'm Dr. John Troyer, Director of the Centre for Death and Society at the University of Bath and I'm here to talk about death, dying, dead bodies, grief & bereavement, and the future of human mortality. Ask Me Anything!


AskScience AMA Series: I'm Dr. John Troyer, Director of the Centre for Death and Society at the University of Bath and I'm here to talk about death, dying, dead bodies, grief & bereavement, and the future of human mortality. Ask Me Anything!

Posted: 27 Sep 2019 04:00 AM PDT

Hello Reddit, my name is Dr John Troyer and I am the Director of the Centre for Death and Society at the University of Bath. I co-founded the Death Reference Desk website (@DeathRef), the Future Cemetery Project (@FutureCemetery) and I'm a frequent commentator for the BBC on things death and dying. My upcoming book is Technologies of the Human Corpse (published by the MIT Press in 2020). I'll be online from 5-6pm (GMT+1; 12-1pm ET) on Friday 27th September to answer your questions as part of FUTURES - European Researchers' Night 2019.

submitted by /u/AskScienceModerator
[link] [comments]

How far can we travel away from Earth?

Posted: 26 Sep 2019 07:03 PM PDT

I'm taking a Cosmology class right now, and I recently watched this kurzgesagt video about our absolute boundary in the universe. So far in class we've mostly just been going over the expansion of the universe, so I tried to justify the assertion in this video to myself: we cannot travel outside of our local group.

The Hubble constant at the current time is 70 kilometers per second per megaparsec. I set up an equation where the change in distance, dx, is equal to the hubble constant times the distance times the change in time, dt. Solving the differential equation, you get that the final distance is equal to about 1.03 times the initial distance over the course of 500 million years. Something about 3 mpc away (the diameter of the local group) would not even increase in distance by a megaparsec. At half the speed of light, you could travel about 77 mpc in this time. This is ~25 times the diameter of the local group.

I know that the Hubble parameter changes in time, but my textbook seemed to suggest that it would not change in any meaningful way over the course of 500 myr. Even if it increased by two orders of magnitude (I tried this by just having it start at two orders of magnitude higher), the distance is still well within travel distance.

Where is Kurzgesagt getting this from, then? I feel like I'm missing something entirely or that I'm wrong about the evolution of the Hubble parameter in time.

submitted by /u/KirsnickBall
[link] [comments]

How active a radioisotope source do you need to get clearly visible (to the naked eye) light from a scintillator?

Posted: 27 Sep 2019 02:11 AM PDT

How do individual pixels come together together to form images?

Posted: 26 Sep 2019 08:13 PM PDT

Hoping I chose the right flair.

submitted by /u/KineticDream
[link] [comments]

Gamma ray bursts can travel faster than light in a jet medium?

Posted: 26 Sep 2019 12:38 PM PDT

https://www.sciencedaily.com/releases/2019/09/190924152835.htm

That article is way over my head, can someone explain?

submitted by /u/PHealthy
[link] [comments]

If someone receives a donated organ, can that organ be donated again when they pass?

Posted: 26 Sep 2019 12:27 PM PDT

How do some Modified Release medication have lower dosage requirements as compared to the instant release medication?

Posted: 27 Sep 2019 02:14 AM PDT

First of all - is there a difference between Extended Release, Substained Release & Modified Release?

Second - the question in the title
For e.g. Metformin, the recommended dosage doesn't change much irrespective of whether you are prescribed the instant release or extended release version. You may be prescribed 500mg Metformin Instant twice a day or 1000mg ER once day which works to the same 1000 mg a day.

But this is not true for all medication.

For e.g. Gliclazide Modified Release is prescribed at a much lower dose than the instant release one

https://www.ncbi.nlm.nih.gov/pubmed/12076188

In a randomised, double-blind, multicentre study, gliclazide MR 30 to 120 mg once daily showed similar efficacy to gliclazide immediate release (IR) 80 to 320 mg/day (in divided doses for doses >80 mg)

How come lesser dosage of the modified release gives same efficacy as the instant release?

Also seen this with other meds like Indapamide, Zolpidem etc.

submitted by /u/TheGlugGlug
[link] [comments]

Do other animals understand and comprehend photos/videos?

Posted: 26 Sep 2019 12:50 PM PDT

Does the volume of water on earth fluctuate from day to day?

Posted: 26 Sep 2019 12:30 PM PDT

Can you make supersonic incompressible flow?

Posted: 26 Sep 2019 11:51 AM PDT

It seems like just increasing pressure in a reservoir and having a small outlet would be sufficient to cause supersonic incompressible flow. (Say the flow is water). This would work through the Bernoulli equation and area*velocity=constant which hold for incompressible flow.
However, recently I came across the equation: (M2-1)dV/V=dA/A. I think this equation should hold for both incompressible and compressible flow. It implies that there must be a throat to compress the flow to Mach 1. Then, the throat must diverge to provide supersonic flow.
Where this doesn't make sense to me is that area*velocity=constant must also hold. So, if the throat diverges, the velocity must decrease since density stays constant.
The only possible explanation I could come up with is that the density actually does change because empty space is created while velocity and area increase?

submitted by /u/PlanesAndRockets
[link] [comments]

Why are some galaxies names things like "Andromeda" and "Sombrero" while others are referred to as "NGC 3923" and "M82"?

Posted: 26 Sep 2019 08:40 AM PDT

Is there an inherent physical reason why Earth's seasons occur over the same period of time as its year?

Posted: 26 Sep 2019 08:41 AM PDT

Do male bees know they will die after mating?

Posted: 26 Sep 2019 04:14 AM PDT

Why do we need spinors?

Posted: 26 Sep 2019 05:19 AM PDT

I understand that there is some important connection between spin and the groups SU(2) and SO(3). It's often pointed out that SU(2) double covers SO(3), and that the Pauli matrices form a basis for the Lie algebra su(2) (up to a factor of i). But I'm having trouble understanding the connection.

As I understand, SU(2) is the symmetry group of spinors (as diagrams like this one point out - you need a double-covering of SO(3) in order to cover all spinor-space symmetries). This is why this group is so important in the theory of spin. A question that just occurred to me is why the Pauli matrices happen to form a representation of the Lie algebra su(2); does the algebra of observables of a system always have to be some representation of the system's symmetry group Lie algebra? But we can put that question to one side.

I'm especially confused because the theory of spin in quantum mechanics is usually presented as (a generalised version of) the theory of orbital angular momentum. The commutation relations between spin observables are derived in terms of the canonical commutation relations of linear position and momentum.

So then, could someone connect this intro QM exposition of spin to the groups SU(2) and SO(3)?

I'm also vaguely aware of Clifford algebra representations of spin. As far as I can tell spin states are represented by rotors which happen to double-cover SO(3). But that just kicks the can down the road: why should rotors represent angular momentum?

Apologies if this question is poorly formed or seems scattered - that's because it is. It's hard to form the question exactly because I don't fully understand its subject matter yet. So any answer, even partial, would be greatly appreciated.

submitted by /u/Movpasd
[link] [comments]

Do sugared soft drinks contain emulsifiers to keep the sugar in solution?

Posted: 26 Sep 2019 06:22 AM PDT

I heard this random factoid as part of a larger argument against "big food", that soft drinks are supersaturated with sugar so they must also contain an emulsifier, lest the sugar form crystals. I know citrus flavored sodas, e.g. Mtn Dew, Sun Drop, Squirt, contain an emulsifier to keep the citrus oil-based flavors from seperating but I was suspicious of the sugar emulsifiers claim.

EDIT TO ADD If soft drinks don't contain such a product, is there even a foodsafe additive that would allow more sugar to be dissolved in water?

submitted by /u/Skipp_To_My_Lou
[link] [comments]