Are HEPA filters likely to pull COVID-19 out of the air? 2020-03-25T01:07:18.833Z · score: 14 (4 votes)
Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes 2020-03-15T10:00:33.170Z · score: 28 (14 votes)
Why don't singularitarians bet on the creation of AGI by buying stocks? 2020-03-11T16:27:20.600Z · score: 32 (15 votes)
When are immunostimulants/immunosuppressants likely to be helpful for COVID-19? 2020-03-05T21:44:08.288Z · score: 13 (3 votes)
The Goodhart Game 2019-11-18T23:22:13.091Z · score: 12 (8 votes)
Self-Fulfilling Prophecies Aren't Always About Self-Awareness 2019-11-18T23:11:09.410Z · score: 15 (7 votes)
What AI safety problems need solving for safe AI research assistants? 2019-11-05T02:09:17.686Z · score: 15 (4 votes)
The problem/solution matrix: Calculating the probability of AI safety "on the back of an envelope" 2019-10-20T08:03:23.934Z · score: 24 (8 votes)
The Dualist Predict-O-Matic ($100 prize) 2019-10-17T06:45:46.085Z · score: 17 (6 votes)
Replace judges with Keynesian beauty contests? 2019-10-07T04:00:37.906Z · score: 31 (10 votes)
Three Stories for How AGI Comes Before FAI 2019-09-17T23:26:44.150Z · score: 28 (9 votes)
How to Make Billions of Dollars Reducing Loneliness 2019-08-30T17:30:50.006Z · score: 60 (27 votes)
Response to Glen Weyl on Technocracy and the Rationalist Community 2019-08-22T23:14:58.690Z · score: 52 (26 votes)
Proposed algorithm to fight anchoring bias 2019-08-03T04:07:41.484Z · score: 10 (2 votes)
Raleigh SSC/LW/EA Meetup - Meet MealSquares People 2019-05-08T00:01:36.639Z · score: 12 (3 votes)
The Case for a Bigger Audience 2019-02-09T07:22:07.357Z · score: 69 (27 votes)
Why don't people use formal methods? 2019-01-22T09:39:46.721Z · score: 21 (8 votes)
General and Surprising 2017-09-15T06:33:19.797Z · score: 3 (3 votes)
Heuristics for textbook selection 2017-09-06T04:17:01.783Z · score: 8 (8 votes)
Revitalizing Less Wrong seems like a lost purpose, but here are some other ideas 2016-06-12T07:38:58.557Z · score: 24 (29 votes)
Zooming your mind in and out 2015-07-06T12:30:58.509Z · score: 8 (9 votes)
Purchasing research effectively open thread 2015-01-21T12:24:22.951Z · score: 12 (13 votes)
Productivity thoughts from Matt Fallshaw 2014-08-21T05:05:11.156Z · score: 13 (14 votes)
Managing one's memory effectively 2014-06-06T17:39:10.077Z · score: 14 (15 votes)
OpenWorm and differential technological development 2014-05-19T04:47:00.042Z · score: 9 (8 votes)
System Administrator Appreciation Day - Thanks Trike! 2013-07-26T17:57:52.410Z · score: 70 (71 votes)
Existential risks open thread 2013-03-31T00:52:46.589Z · score: 10 (11 votes)
Why AI may not foom 2013-03-24T08:11:55.006Z · score: 23 (35 votes)
[Links] Brain mapping/emulation news 2013-02-21T08:17:27.931Z · score: 2 (7 votes)
Akrasia survey data analysis 2012-12-08T03:53:35.658Z · score: 13 (14 votes)
Akrasia hack survey 2012-11-30T01:09:46.757Z · score: 11 (14 votes)
Thoughts on designing policies for oneself 2012-11-28T01:27:36.337Z · score: 80 (80 votes)
Room for more funding at the Future of Humanity Institute 2012-11-16T20:45:18.580Z · score: 18 (21 votes)
Empirical claims, preference claims, and attitude claims 2012-11-15T19:41:02.955Z · score: 5 (28 votes)
Economy gossip open thread 2012-10-28T04:10:03.596Z · score: 26 (31 votes)
Passive income for dummies 2012-10-27T07:25:33.383Z · score: 17 (22 votes)
Morale management for entrepreneurs 2012-09-30T05:35:05.221Z · score: 9 (14 votes)
Could evolution have selected for moral realism? 2012-09-27T04:25:52.580Z · score: 4 (14 votes)
Personal information management 2012-09-11T11:40:53.747Z · score: 18 (19 votes)
Proposed rewrites of LW home page, about page, and FAQ 2012-08-17T22:41:57.843Z · score: 18 (19 votes)
[Link] Holistic learning ebook 2012-08-03T00:29:54.003Z · score: 10 (17 votes)
Brainstorming additional AI risk reduction ideas 2012-06-14T07:55:41.377Z · score: 12 (15 votes)
Marketplace Transactions Open Thread 2012-06-02T04:31:32.387Z · score: 29 (30 votes)
Expertise and advice 2012-05-27T01:49:25.444Z · score: 17 (22 votes)
PSA: Learn to code 2012-05-25T18:50:01.407Z · score: 34 (40 votes)
Knowledge value = knowledge quality × domain importance 2012-04-16T08:40:57.158Z · score: 10 (14 votes)
Rationality anecdotes for the homepage? 2012-04-04T06:33:32.097Z · score: 3 (8 votes)
Simple but important ideas 2012-03-21T06:59:22.043Z · score: 20 (25 votes)
6 Tips for Productive Arguments 2012-03-18T21:02:32.326Z · score: 30 (45 votes)
Cult impressions of Less Wrong/Singularity Institute 2012-03-15T00:41:34.811Z · score: 34 (59 votes)


Comment by john_maxwell on Why don't singularitarians bet on the creation of AGI by buying stocks? · 2020-06-25T00:44:16.658Z · score: 3 (2 votes) · LW · GW

This reddit post has stats from a recent major machine learning conference.  This graph is probably the most valuable.  This post is on a different conference but points to a similar set of companies.  Note that despite their low number of papers, Apple may still be a good investment; my understanding is that they prefer to keep their research secret.

I looked through the portfolios of a number of different AI-focused ETFs.  From what I could tell, they are all more weighted towards random vaguely AI-adjacent tech companies like Spotify, Nvidia, and Shopify than Google--who knows why.  This is the best ETF I could find approximating ML conference publications after a casual search (also accounting for the fact that FAANG do more research than just what is published):

Comment by john_maxwell on Covid-19 6/18: The Virus Goes South · 2020-06-22T07:12:22.072Z · score: 2 (1 votes) · LW · GW

I wonder how things would be different if people used air filters on the recirculating air.

Comment by john_maxwell on Preparing for "The Talk" with AI projects · 2020-06-19T06:39:57.977Z · score: 2 (1 votes) · LW · GW

1. Past experience has shown that even when particular AI risk arguments don't apply, often an AI design is still risky, we just haven't thought of the reasons why yet. So we should make a pessimistic meta-induction and conclude that even if our standard arguments for risk don't apply, the system might still be risky--we should think more about it.

I've heard this sentiment before, but I'm not aware of a standard reference supporting this claim (let me know if there's something I'm not remembering), and I haven't been totally satisfied when I probe people on it in the past.

I agree we should think a lot because so much is at stake, but sometimes the fact that so much is at stake means that it's better to act quickly.

People are great at rationalizing, coming up with reasons to get to the conclusion they wanted. If the conclusion they want is "We finally did it and made a super powerful impressive AI, come on come on let's take it for a spin!" then it'll be easy to fool yourself into thinking your architecture is sufficiently different as to not be problematic, even when your architecture is just a special case of the architecture in the standard arguments.

Agreed, I just don't want people to fall into the trap of rationalizing the opposite conclusion either.

I'm not operating under the assumption that I know more about the AI system someone is creating than the person who's creating it knows. The fact that you said this dismays me, because it is such an obvious staw man. It makes me wonder if I touched a nerve somehow, or had the wrong tone or something, to raise your hackles.

It did.  Part of me thought it was better not to comment, but then I figured the entire point of the post was how to do outreach to people we don't agree with, so I decided it was better to express my frustration.

5. I agree that this is a possibility. This is why I said "say it buys us a month;" I meant that to be an average of the various possibilities. In retrospect I was unclear; I should have clarified that It might not be a good idea to delay at all, for the reasons you mention. I agree we have to learn more about the situation; in retrospect I shouldn't have said "I think it would be better for these conversations to end X way" (even though that is what I think is most likely) but rather found some way to express the more nuanced position.

Thanks for clarifying.

Comment by john_maxwell on Preparing for "The Talk" with AI projects · 2020-06-18T04:20:22.401Z · score: 4 (2 votes) · LW · GW

Moreover, I think that when this choice is made, most people in the relevant conversation will be insufficiently concerned/knowledgeable about AI risk. Perhaps they will think: "This new AI design is different from the classic models, so the classic worries don't arise." Or: "Fear not, I did [insert amateur safety strategy]."

This seems a bit like writing the bottom line first?

Like, AI fears in our community have come about because of particular arguments.  If those arguments don't apply, I don't see why one should strongly assume that AI is to be feared, outside of having written the bottom line first.

It also seems kind of condescending to operate under the assumption that you know more about the AI system someone is creating than the person who's creating it knows?  You refer to their safety strategy as "amateur", but isn't there a chance that having created this system entitles them to a "professional" designation?  A priori, I would expect that an outsider not knowing anything about the project at hand would be much more likely to qualify for the "amateur" designation.

I think it would be very valuable for these conversations to end with "OK, we'll throttle back our deployment strategy for a bit so we can study the risks more carefully," rather than with "Nah, we're probably fine, let's push ahead." This buys us time. Say it buys us a month. A month of extra time right after scary-powerful AI is created is worth a lot, because we'll have more serious smart people paying attention, and we'll have more evidence about what AI is like. I'd guess that a month of extra time in a situation like this would increase the total amount of quality-weighted AI safety and AI policy work by 10%. That's huge.

This isn't obvious to me.  One possibility is that there will be some system which is safe if used carefully, and having a decent technological lead gives you plenty of room to use it carefully, but if you delay your development too much, competing teams will catch up and you'll no longer have space to use it carefully.  I think you have to learn more about the situation to know for sure whether a month of delay is a good thing.

Maybe they have the opposite problems, frequently coming across as overconfident

People seem predisposed to form echo chambers of the likeminded.  I don't think the rationalist or AI safety communities are exempt from this.  (Even if the AI safety community has a lot of people with a high level of individual rationality--not obvious, see above note about writing the bottom line first--I don't think having a high level of individual rationality is super helpful for the echo chamber formation problem, since it's more of a sociological phenomenon.)  So coming across as overconfident in one's knowledge may be a bigger risk.

Comment by john_maxwell on We've built Connected Papers - a visual tool for researchers to find and explore academic papers · 2020-06-13T04:51:27.382Z · score: 2 (1 votes) · LW · GW

Nice!  Would it be possible to build something like this for the LW or EA Forum archives?

Comment by john_maxwell on [Link] COVID-19 causing deadly blood clots in younger people · 2020-05-21T08:03:46.633Z · score: 3 (2 votes) · LW · GW

increase the strength of the infection.

I'd be interested in a link for this.

Comment by john_maxwell on Stanford Encyclopedia of Philosophy on AI ethics and superintelligence · 2020-05-05T04:30:52.958Z · score: 6 (3 votes) · LW · GW

Er, transfer learning?

That's why I said "typically", yes. What I meant was that if you choose 2 random tasks that neural networks are used for, most likely a neural net trained for one will not be useful for the other.

Also, even given transfer learning, the principle holds that you can have a neural net which works great for one task and not for another, just by retraining the last layer. That's what I was getting at with the statement "a 2 hour machine learning tutorial beats weeks of philosophizing"--the fact that retraining the last layer dramatically changes performance across tasks demonstrates that "is intelligence unidimensional" is in some sense a wrong question. If you engage with territory then your ontology becomes finer-grained.

Aside from text, image, audio, point clouds, graphs etc., what have the Romans^Wconvolutions and Transformers done for us lately?

With exactly the same set of hyperparameters? Last I checked the optimal hyperparameters usually vary based on the task, but maybe that has changed.

Anyway, it sounds like you've changed the question from "do neural nets show intelligence is unidimensional" to "do convolutions / attention show intelligence is unidimensional [implicitly, within the scope of tasks for which neural nets work the best]". There are some tasks where neural nets aren't the best.

AI techniques seem to be something like a toolbox. There are cases where a tool works well in a wide variety of situations, and cases where one tool appears to almost strictly dominate another tool. And as you imply, even what might appear to be a single tool, such as "neural networks", actually consists of a bunch of smaller tools which get recombined with each other in conventional ways. So far we haven't found a single tool or way of recombining smaller tools which appears to be universally dominant over all the other approaches. Even if we did, the fact that there was no universally dominant approaches at some earlier phases of AI development suggests that a universally dominant tool may not be a permanent state of affairs. My personal guess is that we will discover something which looks a bit like a universally dominant approach around the time we develop transformative AI... but that doesn't change the fact that AI is not a unidimensional thing from a philosophical perspective. (In particular, as I said, I think it will be possible to use the universally dominant approach to excel in particular narrow areas without creating something that looks like the AGI of science fiction.)

Comment by john_maxwell on Stanford Encyclopedia of Philosophy on AI ethics and superintelligence · 2020-05-04T10:08:39.942Z · score: 2 (5 votes) · LW · GW

Most neural networks are trained for a particular task. They are typically useless for other tasks. So neural networks are actually a great case study in why intelligence does not need to be unidimensional.

If you wanted to argue that neural networks show that intelligence is unidimensional, you'd want to go one level up and argue that the same architecture and training procedure works great across a wide variety of problems, even if the resulting neural nets don't seem to be comparable in intelligence terms. But that isn't exactly true either. (My personal guess is this will become more true as research advances, but we'll retain the ability to train systems which excel along one particular "dimension" while being inferior along others.)

This is one of those cases where a 2 hour machine learning tutorial beats weeks of philosophizing.

Comment by john_maxwell on Rob Bensinger's COVID-19 overview · 2020-05-01T20:55:45.357Z · score: 16 (4 votes) · LW · GW

I just finished a video appointment with a cardiologist where we discussed the clotting thing. Even though he seemed to think I had COVID, and I recently had an abnormal EKG and some mild chest tightness, he thought it was better to avoid blood thinners. Apparently he has been receiving Cochrane reports on COVID before they are publicly available. He said that the increased clotting is usually in patients w/ some kinda predisposition and tends to be worse with more severe symptoms. Even for low-dose aspirin, he thinks the risk of bleeding is larger than the potential benefits. "I've seen all these complications from blood thinners." (I'm 28 FYI.)

Note that despite previous speculation on LW regarding prophylactic use of low-dose aspirin for longevity, a large clinical trial found it wasn't useful in older folks (age 65+). Note this bit:

Significant bleeding—a known risk of regular aspirin use—was also measured. The investigators noted that aspirin was associated with a significantly increased risk of bleeding, primarily in the gastrointestinal tract and brain. Clinically significant bleeding—hemorrhagic stroke, bleeding in the brain, gastrointestinal hemorrhages or hemorrhages at other sites that required transfusion or hospitalization—occurred in 361 people (3.8 percent) on aspirin and in 265 (2.7 percent) taking the placebo.

At the very least, I suggest you change your recommendation from "aspirin" to "low-dose aspirin". Overall, I'm more inclined to trust secondhand accounts of Cochrane preprints than collections of anecdotes in the media.

Comment by john_maxwell on [U.S. Specific] Free money (~$5k-$30k) for Independent Contractors and grant recipients from U.S. government · 2020-04-17T21:44:09.990Z · score: 4 (2 votes) · LW · GW

A friend mentions Divvy and as 3rd party brokers who seem to be moving fast.

Comment by john_maxwell on Where should LessWrong go on COVID? · 2020-04-16T22:02:07.302Z · score: 8 (3 votes) · LW · GW

I just wanna encourage you to not create COVID threads for the sake of creating COVID threads. I contributed to some of those threads, but in retrospect I think my contributions were kind of a waste of time, because there's just been so much COVID discussion on LW and it's not organized very well. (One example: this overview suggested high-dose vitamin D and exercise could be good, I had posted links from sources I think are reasonably credible saying both of those could be harmful. I'm not certain they're harmful but given that the LW userbase skews young, think it's better to avoid high variance treatments since the default outcome for us is good.)

This is one of my big complaints about LW in general but for whatever reason it's been seeming especially acute lately.

Comment by john_maxwell on [U.S. Specific] Free money (~$5k-$30k) for Independent Contractors and grant recipients from U.S. government · 2020-04-16T05:38:15.146Z · score: 2 (1 votes) · LW · GW

As near as I can tell, it is totally legal to apply for a loan from multiple lenders, so long as you don’t accept a loan from multiple lenders. (However, I am not a lawyer or an accountant, and I may be wrong about that.)

FWIW, for the Kabbage website, you're supposed to check a box that says:

"During the period beginning on February 15, 2020 and ending on December 31, 2020, the Applicant has not and will not receive another loan under the Paycheck Protection Program."

Comment by john_maxwell on [U.S. Specific] Free money (~$5k-$30k) for Independent Contractors and grant recipients from U.S. government · 2020-04-16T05:31:19.512Z · score: 2 (1 votes) · LW · GW

The Kabbage application says:

At least 75% of the loan proceeds must be used to cover payrolls costs in order to receive total loan forgiveness. This information will be verified when you request loan forgiveness.

Comment by john_maxwell on [U.S. Specific] Free money (~$5k-$30k) for Independent Contractors and grant recipients from U.S. government · 2020-04-16T05:13:58.730Z · score: 2 (1 votes) · LW · GW

However, 100% of the principle is eligible for loan forgiveness, so long as you spend the <= 75% of the total amount on payroll costs (i.e. pay the money to yourself).

The grammar for this sentence seems a little borked, so I wanted to double check: At most 75% of the money can be paid to yourself?

Comment by john_maxwell on The Unilateralist’s “Curse” Is Mostly Good · 2020-04-16T04:30:30.871Z · score: 2 (1 votes) · LW · GW

The printing press is a tool which lets us coordinate multilateral action differently than we were previously.

Comment by john_maxwell on The Unilateralist’s “Curse” Is Mostly Good · 2020-04-15T01:54:03.253Z · score: 21 (6 votes) · LW · GW

If 90% of the population believes in Religion X, and they all get their opinions on Topic Y from Guru Z, then a naive view of the unilateralist's curse will say that since Guru Z's opinion on Topic Y is shared by a majority of the population, action in line with the Guru's opinion is "multilateral". Any action Guru Z disagrees with is "unilateral", even if the remaining 10% of the population worship a broad variety of gods, follow a broad variety of gurus, and are all in agreement that Guru Z happens to be wrong in this case. (BTW see my recent comment on ideological Matthew effects.)

One of Phil Tetlock's forecasting secrets is something he calls "extremization": Find forecasters who don't correlate well with each other in general, and if they actually end up agreeing on something, become even more certain it's the case. In Bayesian terms, observing conditionally independent evidence counts for more.

The frustrating thing about unilateralist's curse dialogue is that in order to develop the necessary diversity of perspectives to extremize, you need people to be seriously considering the possibility that the group is wrong, probably playing devil's advocate, at the very least not feeling pressure to conform intellectually. But that kind of intellectual noncompliance is the very thing a person concerned with the UC will want to clamp down on if they want to prevent unilateral action.

I think the thing to do is separate out talking and acting: People should be developing their own handcrafted models of the world to make extremization possible, but they should be using ensembles of world models to choose important actions.

Think unilaterally, act multilaterally.

Comment by john_maxwell on The Unilateralist’s “Curse” Is Mostly Good · 2020-04-15T01:42:32.194Z · score: 5 (3 votes) · LW · GW

What sort of historical tech from previous ages do you have in mind which enables unilateral individual action to have a massive influence?

The only thing I'm thinking of are weapons which allow the assassination of important people. All the assassinations of important people which come immediately to mind are cases where I think I would've preferred the important person to stick around.

Comment by john_maxwell on Coronavirus: Justified Practical Advice Thread · 2020-04-08T05:49:32.615Z · score: 8 (3 votes) · LW · GW

Some discussion of whether wearing copper jewelry causes unsafe exposure to toxic copper compounds:

Seems like the case for copper on door handles is stronger than the case for copper on your phone, laptop palm rests, etc.

Comment by john_maxwell on Rob Bensinger's COVID-19 overview · 2020-04-04T07:20:30.591Z · score: 4 (2 votes) · LW · GW

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!)

Comment by john_maxwell on Chris Masterjohn on Coronavirus, Part 1 · 2020-04-02T09:18:55.697Z · score: 4 (2 votes) · LW · GW

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.

Comment by john_maxwell on mind viruses about body viruses · 2020-04-01T07:23:29.308Z · score: 13 (3 votes) · LW · GW

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.

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-29T16:08:57.992Z · score: 6 (3 votes) · LW · GW

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.

Comment by john_maxwell on Are HEPA filters likely to pull COVID-19 out of the air? · 2020-03-25T23:17:18.247Z · score: 2 (1 votes) · LW · GW


...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.

Comment by john_maxwell on Are HEPA filters likely to pull COVID-19 out of the air? · 2020-03-25T01:46:34.943Z · score: 3 (2 votes) · LW · GW

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.

Comment by john_maxwell on Are HEPA filters likely to pull COVID-19 out of the air? · 2020-03-25T01:35:55.709Z · score: 9 (6 votes) · LW · GW

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.

Comment by john_maxwell on LessWrong Coronavirus Agenda · 2020-03-24T23:20:23.318Z · score: 8 (3 votes) · LW · GW

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.

Comment by john_maxwell on LessWrong Coronavirus Agenda · 2020-03-24T05:22:46.982Z · score: 2 (1 votes) · LW · GW

Relevant thread:

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

Comment by john_maxwell on SARS-CoV-2 pool-testing algorithm puzzle · 2020-03-24T04:15:40.258Z · score: 2 (1 votes) · LW · GW

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.

Comment by john_maxwell on SARS-CoV-2 pool-testing algorithm puzzle · 2020-03-24T02:58:22.167Z · score: 2 (1 votes) · LW · GW

This appears to be the university press release, if you consider that to be more reliable:

According to Prof. Roy Kishony, head of the research group in the Faculty of Biology at Technion, “This is not a scientific breakthrough, but a demonstration of the effectivity of using the existing method and even the existing equipment to significantly increase the volume of samples tested per day. This is done by pooling multiple samples in a single test tube. Even when we conducted a joint examination of 64 samples in which only one was a positive carrier, the system identified that there was a positive sample. Although there are some logistical challenges in implementing the method, we expect that it will greatly increase the volume of samples tested per day so that we can identify the asymptomatic carriers. This approach should reduce the chance of infection and flatten the infection curve.”

One hopes that the university wouldn't misquote one of their own professors in their own press release :)

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-24T01:11:59.947Z · score: 2 (1 votes) · LW · GW

Just saw this (h/t Stefan Schubert):

SARS-CoV-2 RNA was identified on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after cabins were vacated on the Diamond Princess but before disinfection procedures had been conducted (Takuya Yamagishi, National Institute of Infectious Diseases, personal communication, 2020). Although these data cannot be used to determine whether transmission occurred from contaminated surfaces, further study of fomite transmission of SARS-CoV-2 aboard cruise ships is warranted.

Comment by john_maxwell on SARS-CoV-2 pool-testing algorithm puzzle · 2020-03-23T20:54:44.769Z · score: 4 (2 votes) · LW · GW

I set up a calendar for medical professionals to book me here:

Comment by john_maxwell on Coronavirus: Justified Practical Advice Thread · 2020-03-22T08:43:49.344Z · score: 3 (2 votes) · LW · GW

Just saw this thread on a subreddit for medical professionals suggesting this could be a bad idea:

Comment by john_maxwell on What should we do once infected with COVID-19? · 2020-03-22T08:27:19.880Z · score: 7 (4 votes) · LW · GW

Like Elizabeth, I remember reading somewhere that COVID-19 often starts in the upper respiratory track and becomes dangerous when it moves into the lungs. In line with that, one idea is to try to control the illness in the upper respiratory tract through sinus rinse/nasal irrigation (be sure to sterilize the water first). I haven't done much nasal irrigation, but I've found gargling with warm salt water to be really helpful for colds. This study found that simply gargling water for 15 seconds 3 times a day reduced upper respiratory tract infections by 36%! Breathing in steam or making use of a humidifier might also be helpful.

This pdf was linked from the 80K podcast. There are treatment instructions starting on page 8. There's also a section on what Traditional Chinese Medicine says you should do :P

There's also a thread on the slatestarcodex subreddit on what to do if you have a severe case and there's no room in the hospital. Another thread on that sub.

Comment by john_maxwell on What should we do once infected with COVID-19? · 2020-03-22T08:03:45.895Z · score: 4 (2 votes) · LW · GW

I have a few extra lozenges I can share, although if you're in the Bay Area, you'll have to drive to a different state to get them. Send me a personal message if you're interested.

Comment by john_maxwell on SARS-CoV-2 pool-testing algorithm puzzle · 2020-03-22T06:59:18.196Z · score: 12 (6 votes) · LW · GW

This is a great question. However, I think we need to know more about the properties of the test before the problem is fully specified: What are the false positive and false negative rates, and how do these numbers change in the pool-testing case?

This FAQ on the CDC website links to this pdf on the FDA's website. I don't have the background to understand most of this, but I pasted some snippets that seem interesting below. Note that it appears this info only applies to a particular CDC-endorsed test being used in the US--I don't know what's in widespread use internationally.

Negative results do not preclude 2019-nCoV infection and should not be used as the sole basis for treatment or other patient management decisions. Negative results must be combined with clinical observations, patient history, and epidemiological information.

False negative rate could be high.

2019-nCoV Positive Control (nCoVPC)

For use as a positive control with the CDC 2019- nCoV Real-Time RT-PCR Diagnostic Panel procedure.

It sounds as though the standard test kit includes 4 test tubes of noninfectious material that should produce a positive test result if things are working properly. This could give a general sense of what dilution levels the test continues to be accurate at.

Page 32 of the PDF has a section labelled "2019-nCoV Markers (N1 and N2)" which keeps referencing "threshold lines". This makes me think that although the test is advertised as providing a discrete positive/negative outcome, it really gives a continuous output along with guidelines for discretization (but in theory this continuous output could be translated into a probabilistic assessment instead, if we had the necessary data and some theoretical understanding of what's going on).

Additionally, it might be possible to make a vague guess about the likely number of infected individuals in a pool as a function of these continuous parameters, esp. if combined with info re: where each is in their disease progression (see time series note below).

There's a "2019-nCoV rRT-PCR Diagnostic Panel Results Interpretation Guide" section which discusses the possibility of inconclusive results. However, I think Table 9 on p. 41 of the PDF weakly suggests that they are rare.

From the "Limitations" section of the PDF:

Optimum specimen types and timing for peak viral levels during infections caused by 2019-nCoV have not been determined. Collection of multiple specimens (types and time points) from the same patient may be necessary to detect the virus.

So now the problem has a time series aspect. Things keep getting more and more interesting ;)

A false negative result may occur if a specimen is improperly collected, transported or handled. False negative results may also occur if amplification inhibitors are present in the specimen or if inadequate numbers of organisms are present in the specimen.

So now we have to worry about whether each individual testee might have "amplification inhibitors" which screw up the entire batch? Hey CDC, are you sure there's no way to do some kind of control amplification, to check if amplification is working as intended regardless of the specimen's 2019- nCoV status?

Positive and negative predictive values are highly dependent on prevalence. False negative test results are more likely when prevalence of disease is high. False positive test results are more likely when prevalence is moderate to low.

"Priors are a thing." Seems obvious, but if someone is going to create a web app that makes it easy to conduct pool tests, it should probably ask the user what the prevalence of 2019- nCoV is in the local population. You don't want a user to blindly trust a prediction made based on an inaccurate base rate.

If the virus mutates in the rRT-PCR target region, 2019-nCoV may not be detected or may be detected less predictably. Inhibitors or other types of interference may produce a false negative result. An interference study evaluating the effect of common cold medications was not performed.

Good to know.

Performance Characteristics

This section looks pretty relevant.

LoD studies determine the lowest detectable concentration of 2019-nCoV at which approximately 95% of all (true positive) replicates test positive. The LoD was determined by limiting dilution studies using characterized samples.


Tables 4 & 5 on page 37 of the PDF looks very interesting, displaying test sensitivity as a function of RNA copies. I'm not sure how to interpret the "Mean Ct" row, or what it means for a dilution to be "≥ 95% positive". I'm also not sure why there are subtables for 2019-nCoV_N1 and 2019-nCoV_N2 (it looks like they represent two different test markers?)

I also don't know what a typical number of RNA copies would be in an infectious specimen.

Tables 4 & 5 make me a bit pessimistic about this entire project, because they imply that a factor of 10 dilution (from roughly 3 RNA copies per μL to roughly 1 RNA copy per 3 per μL) reduces test sensitivity from ~100% to ~50%. Then again, it's possible that these numbers are chosen because the CDC wanted to figure out the precise range that the test broke down in, and in a real-world scenario, an infectious specimen is likely to have way more than 3 RNA copies per μL (stands to reason doesn't it?)

Anyway, the best approach may be an algorithm which takes conditional probabilities (and maybe also prior information about local prevalance) as inputs, so the algorithm can be run with minimal tweaks as more data is gathered regarding the real false positive/false negative rates + the algorithm can be used with any test whose performance characteristics are known.

An alternate frame is instead of thinking of each testee as being either positive or negative for the virus, think of each testee as having some number of 2019-nCoV RNA copies per μL of specimen (0 if they're negative for 2019-nCoV, presumably!)

Through this lens, you could see the problem as an active learning problem where the goal is to learn a regression coefficient for the 2019-nCoV RNA concentration for each testee. If you're using a clever algorithm powered by a good noise model, you will probably sometimes find yourself testing specimens which aren't an even mix of different testee specimens (example: we think Patient A might have a very small number of RNA copies per μL, so we test a specimen which is 50% from Patient A but 10% from Patients B/C/D/E/F because that gives us more information).

Side note: In the course of this research, I happened to notice this note on the CDC website:

I believe that I have found a treatment or vaccine for COVID-19. Is CDC the best place to submit my idea?

BARDA is providing a portal to support U.S. government medical countermeasure research and development. Interested stakeholders can learn more here.

That could be a good link to use once we think we have something which is good enough to share with the US government.

EDIT: If anyone can put me in contact with someone who's actually performed these tests, and ideally also has some knowledge of how they work under the hood, I would love that. Active learning is a topic I'm very interested in. I can program the app if you can answer all of my questions about the testing process. Send me a message via my user page with your contact info.

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-22T02:33:05.679Z · score: 5 (3 votes) · LW · GW

BTW this video might be worth a watch:

The website for this product says it's used for training in major hospitals, so I think it's reasonable to guess that germs really do spread as easily as the video suggests.

Comment by john_maxwell on landfish lab · 2020-03-22T01:50:30.144Z · score: 4 (2 votes) · LW · GW

Here's some contact tracing discussion on reddit, you might want to post there/contact individuals there:

Comment by john_maxwell on Where can we donate time and money to avert coronavirus deaths? · 2020-03-22T01:45:37.268Z · score: 2 (1 votes) · LW · GW

Someone created an /r/CoronavirusArmy subreddit which is trying to figure out how to donate time:

Here are some threads discussing how to donate money:

I think the most valuable projects are those that could be feasibly be deployed in a developing country if COVID-19 were to take root there.

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-21T00:38:32.094Z · score: 4 (2 votes) · LW · GW

Just edited the post with updated info re: which supplements are likely to be helpful.

Comment by john_maxwell on When are immunostimulants/immunosuppressants likely to be helpful for COVID-19? · 2020-03-21T00:22:30.724Z · score: 4 (2 votes) · LW · GW

Update: Apparently some have been interpreting this Twitter thread as an indication that the virus may take advantage of immune system activity to infect you? Which could mean that immunostimulation is bad?

Comment by john_maxwell on Coronavirus Justified Practical Advice Summary · 2020-03-20T01:41:14.306Z · score: 3 (2 votes) · LW · GW also has stuff:

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-19T06:23:22.649Z · score: 3 (2 votes) · LW · GW

Me and my roommate both work from home (and were doing that well before the pandemic). So packages, letters, and maybe the trash person touching our trash bins are essentially the only possible way for us to get infected. It takes less time & attention for us to be paranoid about external contacts than it takes for us to make sure to not touch our face, wash our hands frequently, etc. etc. Comments in this thread updated me in the direction that the procedure I described is excessive, but I'm still handling packages with gloves + bleaching the gloves afterwards (not right away but before using them again) and letting packages dry out for multiple days before touching them or their contents with bare hands. I actually think taking these precautions takes less time & attention than doing a sufficiently careful read of the literature to figure out if I can be less cautious (and remember, even if the literature says X, X is not necessarily true since studies don't always replicate). I also think that as things peak, for those who are immunocompromised, you might as well be really paranoid since your life is at stake and most packages will probably be handled by someone who's infectious.

Comment by john_maxwell on Coronavirus Justified Practical Advice Summary · 2020-03-18T06:21:48.497Z · score: 9 (5 votes) · LW · GW

Chris Masterjohn, who was endorsed by Will Eden once I believe, recently sent an email to his list about the coronavirus where he says among other things

For example, I always recommend vitamins A and D during cold and flu season. I see people making the same recommendations for the coronavirus. But after looking at the research, I'm actually restricting vitamins A and D while the coronavirus threat remains high or uncertain.

He's selling a report he put together which has more details here.

Comment by john_maxwell on Coronavirus: Justified Practical Advice Thread · 2020-03-16T22:20:33.337Z · score: 4 (2 votes) · LW · GW

I wrote a post with a comprehensive disinfection protocol here, although some criticized it for being excessively paranoid.

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-16T20:41:52.355Z · score: 6 (3 votes) · LW · GW

OK, I think I see what's going on--I didn't realize you were pointing to your reply to Vaniver.

I don't think the assumption of drying is necessarily justified--the package could be getting delivered on a humid day. These kind of questions might be really important to someone who has diabetes or something like that.

Thanks for weighing in btw, I'm learning stuff about how to evaluate research here :)

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-16T09:25:57.285Z · score: 2 (1 votes) · LW · GW

The drop-off in infectiousness is documented in the papers reviewed in the paper you cited, which agrees with the parent comment.

Is your claim that the paper I cited agrees with Josh's comment? That's what it sounds like you're claiming. Can you cite the specific sentence in the paper I cited that agrees with Josh's comment? Because all I see is the review repeating the claim "Human coronaviruses can remain infectious on inanimate surfaces for up to 9 days" over and over.

And elsewhere in this thread you said "the results noted in the review are clear that [paper] is not a very hospitable surface", but that is very much not clear as noted in the review--in Table 1, you can see they're citing a study that they summarize as SARS-CoV persisting for 4-5 days on paper.

It could be that the review is summarizing these studies inaccurately. But if you want to earn my trust you have to say something like "yes the review says X but really Y is true", instead of confidently misrepresenting things that I can easily check for myself.

I find it plausible that this review was slapped together quickly in response to the COVID-19 pandemic and a closer look at these studies would find the 9 day figure cited in the abstract to be unjustified. But until that's done in a formal way, I don't see why I should trust you more than the first author of this review (who seems to be a professor at a German university who's written many papers on topics related to this for a variety of journals)--your comments are looking very slapped together as well. BTW, the Journal of Hospital Infection seems legit to me.

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-16T09:08:35.145Z · score: 2 (1 votes) · LW · GW
  1. That wasn't a meta analysis, it was a review.

Thanks, fixed.

  1. The viral load in a cough droplet is rarely as high as 10^5, and the review only said 9 days for viral loads of 10^7, which is silly.

Silly, eh? What if it's not a cough droplet? What if the delivery person is picking their nose?

You're talking about cardboard, which will perform similarly to paper, and the results noted in the review are clear that it's not a very hospitable surface

The review cites a study which allegedly found that SARS persisted 4-5 days on paper. Paper may very well be an inhospitable surface, but that fact does not seem clear from the review...

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-15T20:11:11.930Z · score: 2 (1 votes) · LW · GW

Do you have citations for these claims?

I agree that China's success is evidence this procedure is overkill. Edit: this comment has some potential caveats though--seems the US is probably doing worse than China in terms of ensuring delivery people aren't infected.

wait a day, and the virus will be dead to an extent that you can't get infected.

I linked to a meta-analysis finding that the virus can remain infectious on surfaces for much longer than a day, especially in colder temperatures.

And bleach is [...] bad for your lungs

Good to know. Hopefully wearing a mask will help with that.

Comment by john_maxwell on Comprehensive COVID-19 Disinfection Protocol for Packages and Envelopes · 2020-03-15T19:54:01.859Z · score: 11 (5 votes) · LW · GW

This seems to be

(a) news coverage - so not necessarily reliable, of

(b) a preprint - so not peer reviewed

My article is a peer-reviewed [edit: maybe not very peer reviewed] literature review, aggregating results from multiple studies (that's important).

The 1-2 hour number you cite is for aerosolized virus. The article says the number is 24 hours for cardboard.

However, variability between studies is quite high. Look at Table 1 in my article. Search for the keyword "Paper" and you'll see that for the same amount of virus at room temperature on paper, one study got 3 hours and another study got 4-5 days. (It's possible this is because different strains were used, but that doesn't reassure me either--it suggests that the virus could quickly mutate to be viable on surfaces much longer.)

While it's true that CV DNA can still be detected after several days, this says more about detection technology than CVs virulence.

A quote from the Results section of the paper I cited (emphasis mine):

Most data were described with the endemic human coronavirus strain (HCoV-) 229E. On different types of materials it can remain infectious for from 2 hours up to 9 days.

Comment by john_maxwell on When are immunostimulants/immunosuppressants likely to be helpful for COVID-19? · 2020-03-15T07:06:23.974Z · score: 2 (1 votes) · LW · GW

(Edit: See update comment below)

I emailed Sarah Constantin about this question. I didn't end up hiring her (my parents decided they didn't want to take supplements--luckily they're working from home now), but she did say:

BTW, the apparent "contradiction" isn't really one. Immunostimulants, taken when healthy, reduce the incidence of respiratory tract infections; once you get an infection like COVID-19, the immune response often gets so strong it kills you.

So I think taking immunostimulants on an ongoing basis is a good idea, but you should stop if you think you might be infected with COVID-19.