These pop-up targets are part of an advanced drill, named "friend or foe," that tests shooter reaction times. Some targets have a camera, and others, like these pictured, have a gun. The shooter must decide within seconds whether to shoot. Deborah Amos/NPR hide caption

Silvester Fullard fixes dinner for his 11-year-old son Tavestsiar. When Tavestsiar first came to live with his dad in 2010, he was closed off, Silvester says; "he didn't want to be around other kids." Charles Mostoller for NPR hide caption

U.N. Secretary-General Ban Ki-Moon (in white-and-blue vest) joins other leaders at the 2015 International Women's Day March at Dag Hammarskjold Plaza on March 8 in New York City. Michael Stewart/WireImage/Getty Images hide caption

Having a narcissistic parent doesn't mean you're going to turn out that way, too. GraphicaArtis/Corbis hide caption

Prion protein can be infectious, spreading from cell to cell in the brain. Here four nerve cells in a mouse illustrate how infectious prion protein moves within cells along neurites — wire-like connections the nerve cells use for communicating with adjacent cells. Science Source hide caption

For her trigonometry class, Sarah Hagan (center) uses everything but the kitchen sink: a flower pot, garbage basket, rolls of tape, rubber balls, even loose spaghetti. Elissa Nadworny/NPR hide caption

The new doughnut-shaped building will be a mile in circumference. "The office areas are laid out in little wedges all around the building," says Dan Whisenhunt, Apple's vice president of real estate and development. Anya Schultz/KQED hide caption

The University of Oregon is under fire from students and some employees for turning a student's mental-health records over to its lawyers. Rick Obst/Flickr hide caption