Recent comments in /f/askscience

alacrimonious t1_j9v3vu9 wrote

Reply to It seems like we havent heard anything about carbon nanotubes for almost a decade. is there anything exciting involving those these days? by mintysmellshowntell

You gotta check out Carbon Quantum Dots! I spent 3 hours last night on the wiki page reading all the referenced research papers and seeing what people are doing with them. It's nothing short of incredible!

I don't even know if I could TLDR but I'll try. The CQD's absorb a wavelength of light. Usually UV but capable of absorbing visible light at well and can convert that light to a specific wavelength or electrical energy and with various combinations of doping agents can tailor the CQD's to a specific application.

Some examples. 3D printed rocket fuel, cleaning up oil spills by breaking down the compounds. Optical applications. And a way to split water efficiently without major energy input. Very cool stuff.

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QristopherQuixote t1_j9v3qox wrote

Reply to Will a bag of activated charcoal actually passively purify the air in a room? by gtmattz

This is total bullshit. Unless the air is flowing through the charcoal, the bags of charcoal might cover up the smell but they will not remove the chemicals. Byproducts from 3d printing can be toxic, and you should not breath them for extended periods of time.

You can get a small fume extractor from Amazon used for soldering and have it extract the airborne chemicals. However, that might be insufficient. You could find a decent one for less than $100.

There are extractors available specifically for 3d printing:

https://blog.gotopac.com/2018/10/09/carbon-hepa-filters-for-toxic-3d-printing-fumes-particles-odors/

Allowing 3d printers to run in the open air might be a violation of work safety rules, and you might be able to insist on a full enclosure with a filter for the 3d printers to safely and fully remove the smells/chemicals from the printing runs. If you have a work safety steward, I would raise your concerns with that person. If not, look for the work safety office for the state where you live. I live in Michigan and the state office is MIOSHA

https://www.michigan.gov/leo/bureaus-agencies/miosha/about-miosha/contact

Every state has the equivalent.

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FlippinToaster t1_j9v37a4 wrote

Reply to comment by Jew-fro-Jon in It seems like we havent heard anything about carbon nanotubes for almost a decade. is there anything exciting involving those these days? by mintysmellshowntell

I was also kinda wondering this same thing, and i kinda had allready relegated CNT to the void i label ”engineering problems”.

This is just wonderful comment btw, i just love the comedy of the situation CNT shares with fusion energy. Theoretical physicist’s just being like ”i told you 70 years ago, just heat the thing to 3 000 000K and you have fusion” while the engineers are pulling their hair out.

I totally get some people find this kind of situation frustrating, or some are angry or sad about it. I just try to look at the ”bright side” and find this funny, and not to think too much of it. And i mean no offence to anyone involved!

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Uncynical_Diogenes t1_j9v1zj9 wrote

Reply to How can Doctors tell if one of your kidneys isn't working? by FineLetMeSayIt

We have two kidneys not so that one of them can be a spare, but because they evolved from structures that were already pairs. We never gained an “extra” kidney… we still have two kidneys. In most organisms with dedicated kidney-like-organs, you will find these in pairs along the body, probably due to bilateral symmetry during embryogenesis.

Why don’t we have two of other things, for redundancy? Well, unfortunately, the best response to evolution questions is often: ”why would we?” The benefit of evolving an extra of a given organ would have to outweigh the cost. That’s putting energy and time into something that the organism ideally will never need.

Two kidneys for a human-sized organism is pretty cheap, evolutionarily speaking, for your osmotic-filtering-needs. Annelid worms have two nephridia per segment. But two stomachs, two hearts, four lungs? The “cost” rises very quickly for these structures.

That cost is very high when the only time you would need a spare is a life-threatening injury. The only benefit it confers is a higher chance of survival upon taking catastrophic damage. Organisms that sustain life-threatening injuries don’t often survive them - if you’ve taken enough damage to irreparably damage an organ, the chances of you surviving that are not particularly high, even if you have a spare.

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ChickpeaPredator t1_j9v0qcy wrote

Reply to comment by Beat_the_Deadites in Does the common flu vaccine offer any buffer against H5N1 (Bird Flu)? by Esc_ape_artist

The group B approach is exclusively used by organisms with low offspring investment. As the amount of investment goes down, the quantity of offspring increases.

We aren't like that - it takes a humongous amount of resources to raise a functional human. So we either slip backwards from our humanity and become simpler organisms with less offspring investment required, or we have to expand infinitely to gather enough resources. The latter is impossible, there's always going to be some limit to expansion, so we would be left with the former; backsliding.

You're right in that option B is a viable evolutionary strategy, but it's not a world in which I want to live. I'd rather be a person amongst peers than a king amongst idiots.

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Romarion t1_j9v0mpb wrote

Reply to What are the best alternatives to a double-blind RCT if blinding is impossible: example you cannot have a double-blind RCT to test the effectiveness of masks against covid. What is the best way to test if masks, as worn in real life, are effective? by DenebianSlimeMolds

Asking good questions is the mark of good science, and understanding that the answers have some amount of uncertainty is the mark of good scientists. When scientists suggest some science is settled, be skeptical...1 mole of HCl and 1 mole of NaHCO3 pretty much always yields NaCl, water, and CO2, but science involving humans is never as settled as that.

Randomizing and blinding for human clinical trials is done in part because of the enormous complexity of a human; controlling for all the variables except the variable of interest is not possible (unless you are doing an N=1 trial, which is a different discussion). Randomizing is done in part so that all of the other uncontrolled variables are spread evenly across the participants, and succeeds sometimes, and not so much other times.

Blinding is done primarily to remove conscious and unconscious bias, but in a study examining the transmission of COVID, the only person who really needs to be blinded is the person doing the nasal swab. Positive and negative tests are fairly objective, so once a sample hits the lab bias is no longer an issue.

SO the real question appears to be something along the lines of "if we want to live as normal a life as possible and reduce the spread of COVID, do masks reduce the transmission, and by how much?"

Let's take one infected unmasked person, and put them in a room. We can take 16 uninfected people, each wearing one of 4 masks (no mask, a cloth mask, a surgical paper mask, and an N95 mask). The participants could sit around a table and recite some text, while the infected person walks around the table reciting similar text. Let's leave everyone in the room for 30 minutes.

THEN we check the exposed folks daily for a number of days, and determine the infection rate based on those condition and their masks. While we are waiting for those results, we repeat the experiment every hour (deep cleaning the room in between runs) with the same infected person, and 16 new uninfected people. For the second run, the infected person wears a cloth mask, then on the third run a surgical paper mask, and then an N95 mask for the last run.

You could add more layers; what happens if the air system in the room has the same operating parameters as an airplane cabin? Now you can do 4 more runs, ideally on the same day with the same index infected person.

What are the confounders that will add uncertainty to your results? The immunization status of the participants, whether or not they have previously had a COVID infection (and when), their underlying health status, and a myriad of other variables inherent to each person.

You also need time, space, and money to do such an experiment, and in 2020 that would not have been an ethical experiment so it could not be done. It MIGHT be an ethical experiment in 2023 with the current variants of COVID, but even that is unclear.

And depending on the transmission rates with and without masks, 65 people might not be enough to find significant difference. There are sample size calculators that help us with that; we just need to estimate the transmission rate with and without masks to decide how big we need to scale our study to determine any effect, and the uncertainty around that effect.

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Doc_Lewis t1_j9uzj6n wrote

Reply to Does the common flu vaccine offer any buffer against H5N1 (Bird Flu)? by Esc_ape_artist

It likely has some effect, but specifically it is not targeted to the H5N1 influenza A virus.

Flu vaccines target the H and N glycoproteins, so it would depend on which epitopes of which H and N was in the flu vaccine this year, and how much homology there is between them and H5 and N1.

My gut says it's probably measurable, but not significant enough to really offer any protection.

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xanthraxoid t1_j9uyoii wrote

Reply to comment by aphilsphan in Does the common flu vaccine offer any buffer against H5N1 (Bird Flu)? by Esc_ape_artist

It's worth noting that these tests aren't completely comprehensive. Recall that the nominal shelf life of various Covid vaccines was extended a couple of times - the initial results were interpreted conservatively, but over time more evidence allowed a more confident prediction of a longer shelf life.

When it comes to a vaccine that's not expected to be useful more than ~6 months into the future (nobody's taking the flu jab in the spring, and next year they'll want the new one) there's not really much point in measuring how it lasts beyond that with any degree of rigour.

Providing the shelf life is expected to be good enough for "this year's flu season" (3 months?) they'll most likely just use that figure and move on to more valuable work.

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Krilion t1_j9uxz04 wrote

Reply to comment by riuminkd in Do all thinking creatures on Earth use neurons? Does an example of non-neuron based biological "intelligence" exist? by Wun_Weg_Wun_Dar__Wun

The process for finding a specific random point in a maze usually involves 75%+traversal. It doesn't matter if you're a single entity or not, as the slime mold is just effective running it all in parallel.

Even given the location of an exit, most solvers still end up searching most of the map before finding it.

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