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1500 questions
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Understanding the brain: how are neurotransmitters released in the brain?
I have a basic knowledge of how neural networks work. A potential difference is created that forces sodium, potassium, chloride, and calcium ions to flow which carries an electrical signal to the end of a synapse. From there, the presynaptic neuron…
Dirac
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11
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Why does a fetus drink and urinate into the amniotic fluid?
I was reading this website saying that fetuses urinate into the amniotic fluid. It also mentioned that, because we drink the amniotic fluid, we’ve been drinking our urine for months.
However, why do we produce urine as fetuses? I always believed the…
lightweaver
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11
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2 answers
At what point during an action potential are the sodium potassium pumps working?
I'm trying to understand how all of the potentials during an action potential are created. My question specifically is about the sodium potassium pumps, however I would also be grateful if someone could verify if I have grasped the concepts…
Meep
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11
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2 answers
Can bacteria release free DNA into their environment?
Natural transformation AKA natural competence involves the uptake of DNA into a competent bacterium (for horizontal gene transfer or as a food source). My question is about where this extracellular DNA can come from. Typically this "free" DNA…
James
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11
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What's the technical difference between fainting (and being unconscious) and falling asleep (and sleeping)?
This is actually a popular question along google results but the answers usually sound like:
sleep is voluntary (oh is it?) and healthy
fainting is result of accident and is not normal
I read those answers and I'm like: "You don't say?". So yeah,…
Tomáš Zato
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11
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2 answers
Is global life expectancy normally distributed?
I am trying to find out what the world distribution of life expectancy looks like.
123
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11
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1 answer
How long can human tissue last without blood?
I've heard it said various times that the body's tissues will begin to necrotize after being cut off from the blood supply for only a few minutes, but that can't be true.
A few years ago, I woke up one morning and apparently I'd been sleeping just…
Mason Wheeler
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11
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2 answers
Why do adult insects have 6 legs?
Apparently, there is an advantage to having 6 legs in the insect world. What is that advantage, if anything? Why would such an advantage exist for insects, but not for other, larger land animals?
What do those middle legs do that the front and hind…
DrZ214
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11
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4 answers
How did the first life form on Earth reproduce without DNA?
How did the earliest life forms exist without DNA? The most likely scenario I can think of for life happening from nothing is that, over billions of years, with trillions of water molecules and dust particles and chemicals moving around, eventually…
J.Todd
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11
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Scoring sequence against position weight matrix
I have a weight matrix of length 20 x 15 (amino acids x sequence positions). Each element of my weight matrix is a relative probability
If I have a sequence say "AAPGTGASMHSGLLW" how would I score it against the matrix? I tried taking the product of…
Omar Wagih
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1 answer
The replicator equation vs the Lotka-Volterra equation
Background
The replicator equation with $n$ strategies is given by the differential equation:
\begin{equation}
\dot x_{i} = x_{i} \left( \sum_{j=1}^{n} a_{ij}x_{j} - \phi \right)
\qquad i = 1, \ldots, n
\end{equation}
where $x_i$ is the…
falsum
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3 answers
How can I preserve hair or saliva for future genome sequencing?
Suppose I want to preserve myself so that I can be reproduced as best as possible, in future or be simulated in future. At the moment full human genome sequencing is a bit expensive.
One could get some of my hair or saliva, but what can I do with…
barlop
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11
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2 answers
DNA as an acid?
Possible Duplicate:
Does DNA react in all of the ways most other acids do?
Even if DNA is made up of nucleotide bases, it is said to be an acid. Why is this?
kirty shakthawatt
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11
votes
1 answer
Can oxygen diffuse out through the lungs?
Let's say you accidentally walk into a room pressurized with pure nitrogen (or you're jettisoned into space). Within a couple of seconds, the partial pressure of oxygen within your lungs drops to 0. But there's still a (small?) reserve within your…
rdhs
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Are these Gram stain substitutions acceptable?
In the context of a Gram stain on a blood smear:
Are the following acceptable substitutions and/or what differences could arise by substituting them?
Using methylene blue instead of crystal violet
Using carbol fuchsin instead of safranine
I've…
bobtheowl2
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