What was the rationale behind cleaning the air above people's heads - was eye safety the main concern for you?

To clean the air between the people you need UVC on the ceiling pointed down, and you need a lot of lamps. This isn't something we'd be able to set up in a hall we don't own. Additionally, the efficacy of UVC is proportional to the distance the rays traverse, so we're getting a lot more benefit from an emitter aimed above people than we would from downward facing ceiling-mounted ones.

Eye safety is something we're thinking about, but the risk is at close range. With all of the options we're considering the lamps are at least five feet from anyone's eyes, which is more than enough for safety.

Did you also do any prior modeling of the space before the setup?

We did a little modeling on the UV setup, yes!

when in the future would you expect that kind of data to be easily accessible from the NAObservatory website?

Sorry for being slow (this came out in June) but this data is now linked from our website for the treatment plants that have given permission: https://dholab.github.io/public_viz/001-make-by-city-and-by-virus-dashboards/index.html

the two respirators I know of that do not were designed by amateurs during the COVID pandemic

I'm aware of at least the ElastoMaskPro, Flo Mask Pro, and Envo Pro N95. Are these what you're talking about?

almost all industrial respirators have valves

Sure, but they're also not designed for infection control. If you're using them in a situation where you don't need source control, then a valve is great. But ones designed for medical contexts generally don't have valves.

maybe my concern about evaporation vs making droplets is irrelevant

I think that's the case -- if you look at more recent work they've used a wide range of ways of getting glycol into the air.

I wonder whether fog machines that are already installed in crowd-gathering venues could be used for infection control!

It's more than that: fog machines used today (when used with glycols, which is the normal fog juice) are already performing infection control!

Are you planning any measurements of how far the TEG travels or how effectively the humidifier-generated droplets clean the air?

I'm not, though if anyone wanted to come test efficacy I'd be happy for them to measure the effect of us having it on sometimes and off other times.

it's possible that you were wearing well-insulated shoes

I was barefoot, but I'm also not sure shoes would be that big a component since I was fully in the water?

you just didn't notice the sensation because of adrenaline

I don't remember feeling any shock, and I think I still would have noticed?

twice as fast as it actually goes

Music notation rhythms are relative, so I don't think this has a real meaning?

It's wrong in the sense that it's violating convention for no good reason, and so is hard for people to read. My intended audience is folk musicians who are really used to tunes in 2/2 (and other conventions, like four measures per line), and I'd written in 2/4 by accident.

Your last two Musescore files are missing some separation between 1st and 2nd endings

Thanks! I've uploaded new versions of them that put the repeat sign between the endings, which is also logically where it belongs.

Are child swim lessons common in America? Over here, free swim lessons are now provided for children, and mandatory swim lessons are provided as part of primary school.

It sounds like maybe you're talking about somewhat older kids; is it common for kids in your country to have taken swim lessons by age four?

I would guess the claim afterwards that she couldn't was rationalization, and that the real reason was she was stunned with surprise, just based on the sense that I can't imagine the dress was really that restrictive

The dress was my speculation (and not that it was restrictive, but that it was buoyant under her legs). Her claim was that her legs wouldn't go down, and while I haven't tested this myself in water I think this is probably right: you need to bend your legs to get them under you, and she was keeping them straight due to inexperience with water.

She can't swim yet, no

Maybe even a net positive for her and the family on future water safety.

I don't think so: this could easily have happened when no one was attentive and that would have been a disaster.