Wednesday assorted links
1. How much do you need in the way of masks to stop an epidemic?
2. Robot dog herds sheep on a New Zealand farm.
3. Community labs and DIY biology (New Yorker, interesting piece).
4. John Cochrane talk on reopening.
5. Are airplanes actually pretty safe for Covid-19 risk? (Not endorsing this piece or offering it up as advice, I do not myself know one way or the other. Any opinions here?)
6. “More generally, the entire Yemeni monetary system has split on the basis of banknote age.” The older notes of course no longer can be increased in supply and thus, if priced separately, are more stable in value.
7. Sweden is not getting to herd immunity very quickly. This also seems to imply Swedish policy does not matter very much.
8. On the clustering of coronaviruses, recommended, important. And more here.