Girard Children's Community Garden in Washington, D.C. was created on a vacant lot and is now a thriving community space for neighborhood kids, many of whom are from low-income communities of color.
A peacock butterfly in Hurworth-on-Tees, England, in 2013. Peacock butterflies are one of the species the Big Butterfly Count is tracking, with the help of citizen volunteers.
A pharmacy technician prepares syringes containing an injectable anesthetic in the sterile medicines area of the inpatient pharmacy at the University of Utah Hospital in Salt Lake City.
An autonomous tank is demonstrated in France last month. Leading researchers in artificial intelligence are calling for laws against lethal autonomous weapons. They also pledge not to work on such weapons.
Christophe Morin/IP3/Getty Images
An early prototype of the silicon-chip-sized particle accelerator that physicists at Stanford are working on. Eventually, miniature accelerators might have a role in radiating tumors, the scientists say.
SLAC National Accelerator Laboratory
UCLA researchers are using a radioactive tracer, which binds to abnormal proteins in the brain, to see if it is possible to diagnose chronic traumatic encephalopathy in living patients. Warmer colors in these PET scans indicate higher concentrations of the tracer.