Mechanical engineer Maurizio Porfiri, of the Polytechnic Institute of New York University, designs robot fish. A few years ago, he found that real fish would mill about his aquatic robot, and now he's trying to understand why. His research suggests that it has less to do with how the robot looks, than how it makes fish feel.
Yuan Weijing, the wife of activist Chen Guangcheng, is shown with the couple's daughter in a 2007 interview in Beijing. The girl, now 6, is followed to school every day by Chinese security agents, who always check her schoolbag, according to Chen.
After tough criticism from Republicans, the Obama administration withdrew its proposal for new rules to limit child labor on farms.
The AP reports that yesterday, the Labor Department withdrew the proposed rules "that would ban children younger than 16 from using most power-driven farm equipment, including tractors. The rules also would prevent those younger than 18 from working in feed lots, grain bins and stockyards."
Mitt Romney sweeps five primaries and all but locks up the GOP nomination. Even Newt Gingrich agrees Romney is the presumptive nominee. More veepstakes speculation on Sen. Marco Rubio of Florida and Sen. Rob Portman of Ohio. Two centrist House Democrats bite the dust in Pennsylvnaia, while Utah GOP Sen. Orrin Hatch lives to fight another day.
NPR's Ken Rudin and guest host Mara Liasson have the latest political news in this week's roundup.