Recent comments in /f/askscience

WardStradlater t1_j68o8g5 wrote

Reply to Why can an adult’s GI tract expel C. botulinum spores while an infant can’t? by curiousnboredd

So the exact reason behind why isn’t 100% understood, in fact it took ages to figure out which foods were more likely linked to infant botulism (like honey) and is just a very easy thing to eliminate from infants diets to lower the risk. Infants aren’t born with a developed GI flora of good bacteria which help defend itself, instead their intestines are basically ready to develop their flora by being exposed to good bacteria that can colonize and develop a defense network, thus when the spores are introduced to an infants GI tract, they’re far more likely to colonize and take over in an infant and begin producing the actual botulism toxin that causes infant botulism. An adult’s flora is well developed and the spores don’t have a chance to colonize and begin producing this toxin in the intestines before being destroyed.

However, adults can still get botulism but this is because they eat food that doesn’t just have the spores there, it’s because they’re eating food that has already had the botulism colonize in it, thus it’s already a colonized/grown and heavily present with the actual botulism toxin that the bacteria colonies produce. Nearly anyone that ingests food already colonized with botulism bacteria is going to end up with foodborne-botulism regardless of age of intestinal flora development. An infant is just more susceptible to infant botulism because their intestines are susceptible to allowing the spores to begin colonizing, producing botulism bacteria, and having the botulism toxin produced inside of them.

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mfb- t1_j68nzvy wrote

Reply to Is there an upper limit to structure size in a vacuum? Could a sufficiently advanced civilisation build a galaxy sized structure in space or would it become too massive and collapse in on itself? by CubanHermes

A ring can rotate at just the right rate to counter its self-gravity. No special requirement for the structural strength, you just need to maintain the shape precisely. A size limit would only come from engineering and dark energy, but the latter is still a small effect for a galaxy-sized object.

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TadnJess t1_j68nsae wrote

Reply to can gemstones be melted into a gradient? by Acceptable_Shift_247

Not really, Gem crystals are formed over thousands if not millions of years under very specific heats and pressures in the earth's crust. The only real gem like that I can think of that actually exists is Amatrine, and that is formed when an amethyst crystal gets heated a certain way and part of the crystal turns into citrine. You end up with a crystal that is part purple and part yellow/green. They can be made artificially and are really not too expensive to find. But the thing is, it still is the same mineral (quartzite) not really what you are looking for.

The only practical way to do what you are talking about is to powder the gems and then suspend them in resin. You get a band made that is a channel that goes around the band and then have the resin set in that. This style of jewelry is very akin to the old enameled rings they used to make way back.

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