Are 4000 year old math puzzles really worth solving? @UCSDMathDept Prof. Kiran Kedlaya says solving old problems often gives us the tools we need to untangle modern mysteries. More in @sciam: https://t.co/3bFZGRxFdA Story by @writesRCrowell
What makes a good mask and why we need to upgrade: https://t.co/QbJzCccdAc A good mask is “the most important defense we have” against #COVID19, says aerosol expert @kprather88.