John_Maxwell

If you disagree with something I write about AI, I want to hear! I often find myself posting mainly because I want the best available counterarguments.

John_Maxwell's Comments

Rob Bensinger's COVID-19 overview

I'm confused why people aren't talking about guaifenesin more for COVID. It seems like COVID kills by clogging your lungs up with mucus that's hard/impossible to cough out, and guaifenesin is a drug that loosens congestion. (Probably best to get the stuff without DXM, because you want to be coughing!)

Chris Masterjohn on Coronavirus, Part 1

I took one of the zinc capsules that came free with my last order of zinc lozenges. Then I had a bad gastrointesinal day.

I've noticed this happens if I take zinc on an empty stomach.

mind viruses about body viruses

Agreed that thinking about informational ecosystems is very high leverage. It's not clear to me whether it's better to call for greater individual virtue (as you do here) vs trying to rework the underlying incentive structure (some posts of mine that fall into that general category: 1, 2).

One notion I've found helpful, which is one of the things you're getting at here, is that of "ideological Matthew effects". Basically, the more dominant an ideology is, the less receptive people become to competing ideologies / the more people that ideology has available to shout down critics. Under this framework, contrarians can be really valuable even if they are usually wrong, because they inject diversity into the informational ecosystem. However, unless you're in a betting context like the stock market, contrarianism has an incentives problem--from an individual incentives perspective, a contrarian risks opprobrium/ostracization/etc., whereas society being marginally more correct about topic X is generally a public good.

Recently I was toying with the idea of publicly shaming any well-funded group that doesn't offer cash prizes for the best arguments that it's misguided (possibly inspired by this post). Didn't seem to take very well though.

Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes

Update: I've come down with something which I think may be COVID-19. Even if it isn't, it goes to show that you can't be too careful. (In addition to following a relaxed version of the above disinfection protocol, my roommate and I also went for a hike the other week, but we went off the trail in order to stay a solid 20 feet away from the few other hikers we saw.)

Definitely wishing I had ignored the skeptics in this thread and maintained full paranoia.

Are HEPA filters likely to pull COVID-19 out of the air?

Thanks!

...Most hospitals, though, use a filter with what’s known as a MERV rating of 13 or higher. And for good reason — they can capture more than 80 percent of airborne viral particles.

For buildings without mechanical ventilation systems, or if you want to supplement your building’s system in high-risk areas, portable air purifiers can also be effective at controlling airborne particle concentrations. Most quality portable air purifiers use HEPA filters, which capture 99.97 percent of particles.

That suggests there could be gains from installing HEPA filters.

Are HEPA filters likely to pull COVID-19 out of the air?

Diffusion predominates below the 0.1 μm diameter particle size, whilst impaction and interception predominate above 0.4 μm.[11] In between, near the most penetrating particle size (MPPS) 0.21 μm, both diffusion and interception are comparatively inefficient.[12] Because this is the weakest point in the filter's performance, the HEPA specifications use the retention of particles near this size (0.3 μm) to classify the filter.[11]

From Wikipedia. This Wikipedia article actually seems pretty encouraging--despite 0.3 micrometers being near the filter's weakest point, it still filters out 99.95% of those particles?

If most transmission takes place over ~2 meters, it could be very helpful to install HEPA filters near e.g. hospital desks/beds/doorways. I don't remember observing ventilation ducts near desks/beds/doorways in the hospitals I've visited.

Are HEPA filters likely to pull COVID-19 out of the air?

Some quick Googling and skimming of articles:

A doctor quote in this Buzzfeed article points out that HEPA filters are rated to remove particles of .3 micrometers, and a coronavirus is about .1 micrometer. He says this means HEPA filters won't do the job. EDIT: However, Wikipedia states:

The common assumption that a HEPA filter acts like a sieve where particles smaller than the largest opening can pass through is incorrect and impractical. Unlike membrane filters at this pore size, where particles as wide as the largest opening or distance between fibers can not pass in between them at all, HEPA filters are designed to target much smaller pollutants and particles.

The abstract of this preprint states: "Aerosolized viruses are commonly thought to exist as agglomerates, which would increase the particle size and consequently increase their capture efficiency. However, many of the threat agent viruses can be highly agglomerated and still exist as [submicrometer] particles."

I wonder whether the relevant size is not the size of the virus but rather the size of a cough droplet. This paper seems to have found that droplets are greater than .5 micrometers in size. This article distinguishes between "droplets" (>5 micrometers) and "droplet nuclei" (≤5 micrometers) and says that "droplet nuclei" are the only kind that get transmitted over more than 1 meter. It also cites a couple papers which also say that most droplets are larger than .5 micrometers.

So ability to filter droplets is looking pretty good, assuming the filter doesn't break them up.

This online air filter store cites some research indicating that although HEPA filters are only rated for particles that are .3 micrometers, they end up doing a great job of filtering smaller particles also.

LessWrong Coronavirus Agenda

I want to develop a web app that will make group testing fast and easy. This problem happens to relate closely to my machine learning research interests, and I have an algorithm in mind that I'm excited about. However, the first step to developing software is always to talk to potential users and understand their needs in order to make sure your software will actually solve them. You can share my linkedin profile if you think that will help.

LessWrong Coronavirus Agenda

Relevant thread: https://www.lesswrong.com/posts/pjLgE2efAozz82JmR/sars-cov-2-pool-testing-algorithm-puzzle

I'd love to work on this if someone can put me in contact with a medical professional who understands how these tests work.

SARS-CoV-2 pool-testing algorithm puzzle

I think it may be possible to do even better than the algorithm in this paper if your 2nd round of pooling is allowed to cut across multiple pools from your first round.

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