When he was 59 years old, Greg O'Brien was diagnosed with early-onset Alzheimer's disease. Five years later, he is speaking publicly about his experience, even as his symptoms worsen. Courtesy of Greg O'Brien hide caption

itoggle caption Courtesy of Greg O'Brien

The UASK app helps sexually assaulted college students in D.C. access a range of services, from rides to the hospital to phone numbers for counselors. The information is personalized to their school. Another version of the app, ASK, provides the same resources to non-students. Emily Jan/NPR hide caption

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An employee of the drug company Apotex, examines some Ciprofloxacin at the plant in Canada. Cipro is commonly given to travelers for diarrhea. More than 20 million Cipro doses are prescribed each year in the U.S. Getty Images hide caption

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Cellphones are everywhere in the developing world, as this Nairobi street scene shows. Bill and Melinda Gates believe the phones can be used for everything from farmer education to instant banking. Simon Maina/AFP/Getty Images hide caption

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In November, women in El Salvador marched for the freedom of 17 women accused of abortion, including Carmen Guadalupe Vasquez Aldana. She was pardoned this week. Luis Galdamez/Xinhua /Landov hide caption

itoggle caption Luis Galdamez/Xinhua /Landov

A scorpion fly perches on a leaf at the research farm where Lindgren studied the decomposition of human remains. Scorpion flies are among the first insects to visit a corpse. Courtesy of Natalie Lindgren hide caption

itoggle caption Courtesy of Natalie Lindgren

One demonstrator advocates for paid sick leave at a 2013 rally outside New York's city hall. The city is now one of several in the U.S. to have passed a measure mandating paid sick days. Spencer Platt/Getty Images hide caption

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An example of a human precision grip — grasping a first metacarpal from the thumb of a specimen of Australopithecus africanus that's thought to be 2 to 3 million years old. T.L. Kivell & M. Skinner hide caption

itoggle caption T.L. Kivell & M. Skinner