Dalma Cartagena teaches a class on agricultural science to elementary-school students in Orocovis, Puerto Rico. "I'm preparing them to make good decisions when it comes to the environment and healthy foods," she says. Greg Allen/NPR hide caption

Jon Rogers is hugged by his wife, Maryellen, following services at St. Frances Xavier Cabrini Church in Scituate, Mass., in June 2014. Jessica Rinaldi/Boston Globe via Getty Images hide caption

The posterior end of the Loa loa worm is visible on the left. The disease-causing worm can now be located with a smartphone/microscope hookup. That's a big help because a drug to treat river blindness can be risky if the patient is carrying the worm. BSIP/UIG via Getty Images hide caption

Registered nurses Cassie Gregor (from left), Camellia Douglas and Mike Montalto monitor patients in intensive care units scattered around North Carolina. Kevin McCarthy/Carolinas HealthCare System hide caption

Oil pump jacks in Williston, N.D., in December. Oil prices have been on the rise, but some analysts say the global economic slowdown, fracking and the rise of alternative energy will mean less demand and lower prices. Eric Gay/AP hide caption

Loki's Castle, the field of deep sea vents between Norway and Greenland, is home to sediments containing DNA from the newly discovered archaea. R.B. Pedersen/Centre for Geobiology, Bergen, Norway hide caption

Jessica Adams formerly worked at the Planet Hollywood casino and resort. Now she teaches fourth grade at Robert Forbuss Elementary School. Eric Westervelt/NPR hide caption