Thursday assorted links

1. There is massive synaptic pruning between birth and adulthood.

2. Some major city populations from 1854.

3. From Samuel Hammond: “The AI boom is doubly upsetting to progressive economic commentators because it a) shows “financialization” was largely a macro story that eventually solved itself, and b) the boom is being driven by AI rather than their hoped-for “green transition”.”  Plus it shows the internet and social media really were worth it, and that many tech companies are run by geniuses not superficial idiots.

4. The safety of mRNA vaccines.

5. Do the optimistic live longer?

6. How many people have ever lived in the United States?  And what percentage of them are living here now?

7. What is going on with SpudCell? (NYT).