Recent comments in /f/askscience

Pharisaeus t1_j76dlcb wrote

Reply to extremely long stick additional questions? by Unnombrepls

> If we push the stick 10 cm, does it mean the stick is 10 cm shorter before the push reaches the other end?

Consider that this "stick" is not really a rigid body, but rather a large "spring", and it can compress (at atomic scale). So yes, the stick would be, from certain point of view, shorter while the push is being propagated.

> additional force to transiently deform it

Again, since it's a spring, there is no additional force needed, because the energy is conserved (aka: the spring will uncompress, releasing this "deform" energy) back.

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gilgwath t1_j760ttt wrote

Reply to Back in the late 90s, I remember hearing that scientists “cloned a sheep”. What actually happened with the cloning, and what advancements have been made as a result of that? by foxmag86

TL;DR: I think cloning will never be a really viable technology for industrial use. At least not on its own. Not because it's hard problem to solve, but it doesn't scale well. That's why there is little investment and slow development.

Let's assume you cloned a sheep. Congratulations, you now get to care for a baby sheep. You need sheep milk to feed it, you need to provide it with shelter, warmth etc.

That's cool if you cloned one sheep for the lulz. But we want to make some money here. So we clone 1000 sheep. Now where do you get the milk from? From a 1000 other mother sheep who also had at least 1000 baby sheep. You also need a massive lab AND a massive pen to keep your sheep. Workers to do the cloning AND workers to take care of the baby sheep.

If you just want to double your sheep output, it's much easier to just have double the amount of sheep and have them reproduce naturally. No lab required, the herd mostly takes care of their needs.

You've also sloved none of the other problems big scale animal farms come with: methan emissions, land and water usage, animal cruelty etc. You also opend the pandoras box of ethical questions around cloning.

Next question is, will you be able to sell you produce at a competive price ahd enough customers?

Assuming you somehow manage to make it profitable, all of this only works until someone really figures out how to grow meat in a lab at a large scale.

There's no really goo business case for it, so there's no one who's really keen on spending millions to perfect the technology, industrialise it and then build a business on it.

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CrazyisNSFW t1_j75sd1q wrote

Reply to Why do some allergies get worse over time and some better? And how does allergen desensitivity work without making the reaction worse? by DontDoDrugs316

Gross oversimplification: After being exposed to allergen, your body creates memory of it. First exposure is usually mild, you may not even notice it. But your body creates memory as a defense mechanism. Next time you're exposed to allergens, your body gives stronger and quicker response. That's why your allergy reaction can be worse with time.

With desensitization, you're exposed to allergens in such a small dose that you're not reacting to it. Desensitization tricks your body into thinking that the allergen is just a normal thing in environment and you tolerate (desensitized?) the allergens better with time. Of course this is not possible (yet) for every allergens and you should be under close supervision in case something goes wrong and you have severe reaction.

Immunology is really complex but amazing science field.

PS: if you're interested, probably you should search for "Type I (IgE-mediated) hypersensitivity".

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speculatrix t1_j75ni1f wrote

Reply to Does the central part of my vision see in a different frame rate than the outer part? by Calvinkelly

Yes, only the central part of your retina, called the fovea, has the best high quality vision for colour and resolution, that's part of the macula. This relies on light sensitive cells called cones.

The outer retina uses cells called rods which are more sensitive to light with a faster response time, and are better for night, but only offer monochrome vision. This is thought to be a survival trait, to see the movement of predators at night in your peripheral vision.

So, that full colour vision you have? Your brain is faking it.

https://www.kenhub.com/en/library/anatomy/photoreceptors

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nasalemons t1_j75ljw6 wrote

Reply to Why do some allergies get worse over time and some better? And how does allergen desensitivity work without making the reaction worse? by DontDoDrugs316

So this is a gross simplification but some allergens get worse over time because the more you are episodes to it the higher chance your body can create a reaction to it. And with desensitization basically you start with a teeny tiny dose we hope that you don’t react to and very slowly increase it to a point where you may have a mild rash or very mild itchy throat but it’s ok overall

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