New Orleans Mayor Mitch Landrieu speaks about his role in reinvigorating the Louisiana port city. Landrieu was voted "America's top turnaround mayor" in a survey of mayors compiled by POLITICO Magazine. He first took office in 2010, and is serving his second term as the elected leader of the city devastated by Hurricane Katrina in 2005 and impacted by the BP oil rig explosion in 2010.

Music: Impromptu in Blue by Kevin MacLeod is licensed under a Creative Commons Attribution license.
Artist: www.incompetech.com/

Emily Oster evaluated data behind many of the accepted rules of pregnancy. (Should you drink caffeine? Is sushi OK?) She says most advice given to moms-to-be is wrong. More recently, she's been studying how grocery store purchases change once a person has been diagnosed with a health challenge like diabetes. Household scanner data "helps us look at people outside of a monitored health setting, and really see in the real world what are the changes people make, what changes are impossible to make, and who is able to change a lot," she says.

Tyrone Hayes is known for his research findings regarding the effects of the herbicide atrazine on frogs. Atrazine is often used by corn farmers, but Hayes' research illuminated serious questions about its safety. Syngenta, the manufacturer of atrazine, launched a campaign to discredit both Hayes and his research, which resulted in the settlement of a multi-million dollar class-action lawsuit against Syngenta.

When she was in her 20s, Maya Ajmera founded The Global Fund for Children. The non-profit invests in innovative organizations working with some of the world’s most vulnerable children. She says scaling an organization doesn't always mean scaling out. Sometimes it can be down (serving more in the community) or up (advocating for your idea on a wider stage.) Her latest book is called Invisible Children: Reimagining International Development at the Grassroots.