But why expect differential brain drain between Africa and Asia
Here is a throwaway guess: because Asia is rapidly developing and Africa is not. If you're very smart and in (ex-Japan) Asia, you can stay and be successful (make millions / cure cancer / become a pop star / etc.) locally. It's a fluid growing environment. But if you're in Africa, your chances of local success are much smaller and, correspondingly, your incentives to emigrate are much higher.
People want to tell everything instead of telling the best 15 words. They want to learn everything instead of the best 15 words. In this thread, instead post the best 15-words from a book you've read recently (or anything else). It has to stand on its own. It's not a summary, the whole value needs to be contained in those words.
I'll start in the comments below.
(Voted by the Schelling study group as the best exercise of the meeting.)