There are several hundred people who stayed in the Ebola-affected countries and continued to do the work, put themselves at great risk because medical workers are the most likely to be infected because they're helping out when the person's health is deteriorating, including quite a bit of bleeding as they're getting very, very sick.

The 'Billionaire' song is what my kids tease me with. They sing it to me. It's funny.

Lectures should go from being like the family singing around the piano to high-quality concerts.

The kids are a big part of my schedule.

There are several hundred people who stayed in the Ebola-affected countries and continued to do the work, put themselves at great risk because medical workers are the most likely to be infected because they're helping out when the person's health is deteriorating, including quite a bit of bleeding as they're getting very, very sick.

We're still missing about a dozen vaccines that will make a huge difference. For adults, we've got HIV and TB are still huge; for kids malaria is still killing a half million kids a year out of that 6 million. We probably need some vaccines, but we need a little more data to make sure we're getting the vaccines that will save the most lives.

The world is not flat, and PCs are not, in the hierarchy of human needs, in the first five rungs.