How can mothers with HIV avoid passing it to their kids? In South Africa, Mitchell Besser tapped a new resource for healthcare: moms themselves. The program he started, mothers2mothers, trains new mothers to educate and support other moms.
Lee Smolin is a theoretical physicist, working mainly in the field of quantum gravity. He's a founding member of the Perimeter Institute for Theoretical Physics in Canada, and the author of The Trouble With Physics.
To power his family's home, young William Kamkwamba built an electricity-producing windmill from spare parts and scrap -- starting him on a journey detailed in the book and film "The Boy Who Harnessed the Wind."
Jacqueline Novogratz works to enable human flourishing. Her organization, Acumen, invests in people, companies and ideas that see capital and networks as means, not ends, to solving the toughest issues of poverty.