2025-01-23 21:00:00
I think of a standard contra dance as running 8pm-11pm: three hours is a nice amount of time for dancing, and 8pm is late enough that dinner isn't rushed. Looking over the 136 regular Free Raisins dances from 2010 to 2019 matches my impression: 85% were 3hr, 62% started at 8pm, and 51% did both.
I think this is out of date, however, and dances now tend to be earlier, shorter, or both. For example, in the Boston area the regular dances are:
And, as of this Sunday, BIDA now additionally has a 4:30-7:30 dance on 4th Sundays.
Similarly, while I don't have times written down for Kingfisher gigs the way I do for Free Raisins ones, when I look over the last twenty regular gigs we've played I see eleven (55%) are 2.5hr or shorter, and fifteen (75%) started at 7:30 or earlier. Only one (the excellent Flying Shoes dance of Belfast ME) was 8-11.
I don't know what things looked like before I was old enough to notice, but I did find a bit of history from Boston's Thursday dance:
On a cold Thursday night in February of 1978, dancers, Rod and Randy Miller, and Tod Whittemore were waiting in the lobby at the Cambridge YWCA for the aerobics class to end. At the stroke of 9pm we rushed into the hall to set up the sound equipment and tune up, while the dancers changed out of their winter clothes. At 9:10 the first Thursday Night Dance began.
I don't think any dances start that late today, though it's also possible that 9:10 was something temporary due to difficulty finding a spot that was available at the right time?
Overall, I prefer the earlier times, which are easier for me both as a parent and musician. I'm excited about bringing my kids to the new 4:30-7:30 BIDA dances, and dances that end sooner are easier to drive a long way home after. I'm less excited about the shorter dances: it means the effort of getting to and from the dance, setting up the hall, etc is amortized over less time dancing, and it makes the overall evening feel compressed. On the other hand, I do think shorter dances can be the best of a few bad options when handling declining attendance: it's not a great experience trying to keep a dance fun when it's 10:45 and you're having trouble scraping together enough people for a triplet.
2025-01-21 21:00:00
I make breakfast for the kids most mornings, and one thing I didn't realize before I started playing with an air quality monitor was how much this puts smoke in the air. It's not like cooking Naan or searing meat where if I don't put a fan in the window the smoke alarm will go off, but apparently it's quite a lot of particles:
While I initially got interested in air quality from an infection reduction perspective, I'd also prefer not to be breathing smoke. How much does an air purifier help? What about opening a window? Running the little vent fan over the stove that doesn't seem to do anything?
I decided to run some tests. In each case I'd set up my M2000 in the kitchen and start cooking breakfast for the kids. For consistency, I only did this on days when I was making the most common option: crepes. While it would have been best to try each condition a few times to learn what sort of variability there was, I wasn't that patient.
The conditions I tested were:
Control: no attempt made to reduce smoke.
Over-stove Vent: turning on the vent fan on our over-stove microwave. It doesn't vent outside, and it doesn't seem to have any sort of fine filter that could catch little particles, but possibly it does something?
Open Window: opening a window. I didn't put a fan in the window or anything. This is the one I'd expect to have the most variability in practice since there should be a big difference between a more windy and less windy day. I don't remember how windy it was when I tested this.
1x AP-1512 (auto): a Coway AP-1512 purifier on the "auto" setting. It runs on "low" most of the time, and then ramps up to "medium" and then "high" when it detects particles. For a long time we had one of these on top of our fridge.
1x AP-1512 (high): same, but set full-time to "high". This isn't something we'd normally do because it was too noisy, but I was curious how much of an effect it had. I ended up analyzing the data in a way that wouldn't capture this benefit, though.
2x AP-1512 (auto): two of the AP-1512 purifiers, both on "auto". Until recently this is what we had in our kitchen.
2x AP-1512 (auto) + Over-stove Vent: the same, but also turning on the over-stove vent.
2x AP-1512 (auto) + 1x 3Pro (6): instead of the vent, turning on the Airfanta 3Pro I mounted in the kitchen. I ran the 3Pro on its highest setting, representing what we usually do: when we hear the AP-1512 spin up to high, we bump the 3Pro from it's normal quiet 2/6 up to 6/6. This is our current kitchen setup.
While I liked the idea of cooking the same breakfast each time, it didn't make a consistent amount of smoke. Some days I let the pan get a little hotter, sometimes I would forget a crepe in the pan, etc. What should be comparable, though, is the rate at which smoke particles decreased. This should be a process of exponential decay: every minute a consistent fraction of the particles should make their way out the doors into other parts of the house, settle out of the air, be caught in a filter, etc.
I wrote some code, with a significant LLM speedup, to plot the decay I saw in each case. For each example I started estimating after the peak when it seemed be entering its exponential decay phase, and then stopped counting when it fell below 50ug/m3:
Since this is exponential decay, however, a logarithmic y-axis better allows us to judge how good the model is:
Conclusions:
The over-stove vent was essentially useless. I think the benefit we saw was probably due to slightly accelerating the transfer of air between rooms, but since there are also people in the other rooms this isn't a real benefit.
Opening the window helped much less than I expected. Before running this I thought that the window was great, except for the amount of heat you lose to (or in the summer receive from) the environment. But at least without putting the fan in the window it only cuts the time about in half,.
Adding a single air purifier is a big improvement. Looking at these charts, I probably wouldn't bother getting more than one: a half life of four minutes is pretty good.
The second air purifier didn't help much. I don't know how much of this is noise from test to test, and how much is that I put them right next to each other (on top of the fridge) instead of the more ideal situation of opposite sides of the room.
Adding the 3Pro helped a lot, probably because it's almost twice as powerful as the AP-1512.
One benefit I'm not capturing here is what happens during the time when you're producing smoke: can your purifiers keep up with it, or are they playing catch-up? This isn't really something I was set up to measure, since I couldn't generate a consistent initial burst of smoke, but eyeballing the results they do look to be in the expected direction.
I did most of this work when Lily was asking for crepes all the time, but aside from what I'm guessing was a one-off this morning that's not what she wants these days. If at some point she changes her mind, I'd like to test:
A fan in the window pointing out.
That, plus opening a kitchen window.
That, but a dining room window instead.
The 3Pro alone.
The main scenarios above, again, to measure consistency.
2025-01-19 21:00:00
Before our oldest went lactovegetarian I used to make eggy crepes, boosting protein by adjusting the recipe to maximize egg content without giving up crepe flavor and texture. With our youngest, however, I have now (by this metric) the optimal crepe:
Ingredient:
I had been making crepes for Anna and lactovegetarian crepes (milk, flour, flax) for Lily. I would ask Nora what she wanted, and she preferred Anna-style. "Eggy eggy eggy!" I started asking if she would like them more eggy, and she was very enthusiastic. Over time I reduced the non-egg ingredients until it was entirely egg, and she continued to be a fan. It initially surprising to me that Nora wanted to go all the way in this direction, but since sweet omelettes are a thing it probably shouldn't have been.
She usually eats them with nutella and raspberry sauce, and sometimes whipped cream.
2025-01-18 21:00:00
In general, you're not supposed to wear a beard with a respirator mask (N95, P100, etc), at least not in a way where you have facial hair under the seal:
But how much worse is the fit? A P100 with a beard is going to filter less well than a P100 without a beard, but does it do as well as an N95? Or is it hopelessly compromised? And is stubble as bad as a full beard? Does length matter? In an emergency where I really need my mask for protection should I shave?
Bottom line up front: with my rough DIY test setup I got 80% filtration with a long beard, 92% with a short one, and 99.7% with stubble. But see my note at the end about a weird effect I saw.
What was my test setup? The goal is to measure the difference between filtered and unfiltered air. I have a Temtop M2000 meter, which I'd bought to measure air quality for testing my ceiling fan air purifier idea, so I can use that as a sensor. Burning matches is still a fine way of putting enough smoke in the air that I can see differences. And then I can measure the effect of the mask by measuring at my 3M HF-802SD elastomeric respirator's exhale valve, with the meter in a bag, and seeing how smoky it is (pm2.5). With the filter cartridges inserted I can measure the effect of the mask, while with them removed I'm measuring essentially no filtration. The ratio of particles with vs without the filters is my filtration efficacy.
This isn't perfect:
My lungs or the the non-filter parts of the mask might be doing some filtration.
My seal with the bag might not be 100%.
The bag needs to be unsealed to let air out, or it will burst. But maybe this also lets a little smoky air in.
All of these are off in the same direction, however: my measurement is likely to be a lower bound in filtration efficacy.
To actually build this I made a small hole in a gallon ziplock, and attached it around the vent of my elastomeric respirator. The first time I did this I used packing tape, which didn't work very well and kept coming loose:
I did it again with duct tape:
I made sure to get a good seal all the way around:
Then I realized I wanted to test this with a pretty long beard to start, so put this on hold for a month while growing out my beard. I got to maybe 1 1/4":
Here's it combed to show the full length, though for all these tests I had it flat against my face.
I put on the mask, put the meter in the bag, and the bag started to inflate:
The mask has a fit test button, which blocks the inhalation valve: if you can still breathe in with it pressed you know air is making its way under the seal. I didn't feel much air coming in, but I did feel some.
I took a series of measurements, alternating filter status. Qualitatively, each time I put the filters in/out it immediately changed whether I could smell smoke.
| Filters? | pm2.5 | pm10 |
|---|---|---|
| No | 328.5 | 509.9 |
| Yes | 51.5 | 76.5 |
| No | 264.0 | 400.3 |
| Yes | 49.7 | 74.4 |
| No | 199.2 | 302.5 |
Since I expected the level of smoke in the room to slowly drop over time, doing interleaved measurements was quite important.
With a full beard, it looks like the mask cut pm2.5 from 263.9 to 50.6 (-79%), and pm10 from 404.2 to 75.5 (-81%).
Then I trimmed my beard with a bead trimmer set to 3/8":
This is where I normally trim by beard to:
I tried combing it out, but at this length it doesn't do anything:
I made more smoke and repeated the measurements:
| Filters? | pm2.5 | pm10 |
|---|---|---|
| No | 349.1 | 555.3 |
| Yes | 22.9 | 34.6 |
| No | 338.6 | 539.3 |
| Yes | 25.1 | 37.9 |
| No | 264.4 | 418.5 |
This time the filters brought pm2.5 from 317.4 to 24.0 (-92%) and pm10 from 504.4 to 36.3 (-93%).
Then I used the shaver with no guard to remove as much of my beard as I could, getting down to maybe 1/32" stubble:
And from the front:
More measurements:
| Filters? | pm2.5 | pm10 |
|---|---|---|
| No | 436.2 | 713.2 |
| Yes | 1.0 | 1.4 |
| No | 307.0 | 486.6 |
| Yes | 0.8 | 1.0 |
| No | 261.1 | 417.4 |
The filters now took pm2.5 from 334.8 to 0.9 (-99.7%), and pm10 from 539.1 to 1.2 (-99.8%). This is great!
Additionally, when I tried the fit test button I now couldn't breathe in at all, which actually felt a bit terrifying.
Overall I'm pretty happy with these results, except for one wrinkle: the meter reliably read a higher number when measuring my exhalant than it did in the ambient air. How could that be?
I tried a few more tests:
Putting the meter in the bag and not blowing in: same as ambient, then slowly decreasing (probably particles settling?). It never plateaued, just kept going down slowly.
Breathing directly into the bag with no mask: elevated from ambient
Using an air mattress pump to inflate the bag: elevated from ambient
Repeating my test in a room with minimal smoke: probably same results but harder to tell because the numbers were small.
Here are the numbers from what I think is the clearest test, using the pump to inflate the bag:
| Status | pm2.5 | pm10 |
|---|---|---|
| Ambient | 156.4 | 235.1 |
| In bag, after waiting and just before pump | 37.0 | 54.9 |
| With pump, after plateauing | 219.6 | 327.5 |
| Ambient | 117.5 | 177.7 |
I don't know where this is coming from, but possibly it's due to pressure? I suspect that whatever the effect is it's a scalar effect, and so is compatible with interpreting filtration ratios, but I don't know for sure.
This was also the first time my kids had seen me without a beard:
2025-01-17 21:00:00
In the aftermath of a disaster, there is usually a large shift in what people need, what is available, or both. For example, people normally don't use very much ice, but after a hurricane or other disaster that knocks out power, suddenly (a) lots of people want ice and (b) ice production is more difficult. Since people really don't want their food going bad, and they're willing to pay a lot to avoid that, In a world of pure economics, sellers would raise prices.
This can have serious benefits:
Increased supply: at higher prices it's worth running production facilities at higher output. It's even worth planning, through investments in storage or production capacity, so you can sell a lot at high prices in the aftermath of future disasters.
Reallocated supply: it's expensive to transport ice, but at higher prices it makes sense to bring it in from much farther away than would normally make sense.
Reduced demand: at higher prices people who would normally buy ice for less important things (ex: drink chilling) will pass.
Reallocated demand: if you have a chest freezer full of food, you get more benefit from a given quantity of ice than I would with a mostly empty fridge. All else equal, you are willing to pay more for ice than I am.
On the other hand, raising prices in response to a disaster is widely seen as unfair:
Allocation by price is never great for people who have less money, but a disaster makes this existing inequality more painful.
Store owners are on average richer than customers, so profits here are moving wealth from poorer people to richer ones.
Normally prices are kept in check by people shopping around, either by observing prices in a range of places or by talking with friends. These are both disrupted in disasters, which would likely allow sellers to charge more.
So raising prices in emergencies is generally strongly socially discouraged and often also illegal. Stores quickly sell out, there's no increase in supply, and allocation is relatively arbitrary.
Is there a way to get the benefits of keeping prices responsive, while mitigating some of the unfairness?
Consider the introduction of congestion pricing in NYC. Charging money to keep people from overusing a common resource is a traditional economics solution, reducing traffic jams and allowing streets to move more people in less time. While this even helps people who can no longer (or never could) afford to drive, by speeding up buses, it is still often considered too unfair to implement. The NYC approach, however, of charging drivers but then using the money to fund public transit, resolves enough of the unfairness to be put into practice.
What could something similar look like for disasters?
Sellers can, as in normal times, choose what prices to offer their goods and services at.
Price increases beyond documented increases in the cost of doing business are taxed at some high rate. Something in the range of 65%: high enough that most of the profits are going to the public, but where it's still worth sellers putting in serious effort to increase supply.
This tax money goes to help people affected by the emergency.
While this still has some of the downsides of existing price gouging laws [1] I think it's quite a bit better than the status quo.
The biggest advantage is that if the government disagrees with you about how much of your price increase is due to increased costs, it can be sorted out later. There are famous cases where someone tried to increase supply in a disaster by doing something unusual (ex: renting trucks to drive generators or ice hundreds of miles into hurricane-affected areas) and then were prevented from selling. Much better to have a system where we all agree they're good to go ahead and sell, and tax disagreements can be worked out afterwards. It still doesn't fully remove the risk that the government will disagree with you and make your efforts not worth your while, but at least you're arguing with a judge in a courtroom where you can present evidence, and not a cop in front of a mob.
It also:
Gets us some of the benefits of flexible prices, at least to the extent that sellers believe they'll be able to convince a judge about their increased costs.
Helps shift culture in a direction of accepting and expecting prices to change based on conditions.
Transfers money from rich people (who pay inflated prices) to poor people (who receive disaster relief).
Would people be more ok with responsive prices in emergencies if the money were primarily going to disaster relief?
[1] I've previously written about discouraging
investments, but another issue is not handling cases where people
might be convinced to sell something they wouldn't normally. For the
latter, imagine an empty nester couple living in a 3BR in LA. They
prefer to have the house to themselves, but for $5k/month would be
willing to rent out their guest room. In normal times no one would
pay $5k, so they don't bother putting it on AirBnB. With the
emergency, however, there might now be people willing to pay this
much. There's no way for the owners to demonstrate increased costs,
though, so it would probably be illegal for them to list it for $5k
both under current laws and with my proposed change above.
Similarly, say I have a bunch of $150 air purifiers because I'm especially concerned about infectious aerosols, and then with a nearby wildfire stores all sell out. By default I would keep them and enjoy my clean air, but I'd be willing to sell a few for $300 each. That would benefit both me and the buyers, but same issue.
2025-01-16 21:00:00
My neck is not great, and spending a lot of time looking down at my laptop screen really aggravates it. After damaging my screen a year ago I used a stacked laptop monitor that folded up, and it worked well. The main place I tended to use at full height was call booths, since otherwise I was usually at a desk with a real monitor or in a meeting with people where I wanted my monitor not to block my view.
My laptop eventually died, and the new one has a screen again. In many ways this is pretty great: my backpack is lighter without carrying around an extra monitor, walking to a conference room I don't have to worry I forgot my monitor, I'm not fiddling with cables. But I do really miss it on calls in the phone booths.
The booths at my work have a kind of soft material that works great with velcro, though, so I decided to try sticking my monitor up that way. It works great:
These monitors are only ~$50, so after talking with our operations staff we now have them in each call booth:
I'm very happy with these, and my coworkers who don't have neck issues have said they like being able to have notes open on one screen and the call on the other.