Jon HamiltonJon Hamilton is a correspondent for NPR's Science Desk.
The fix was in for this rhesus macaque drinking juice on the Ganges River in Rishikesh, Uttarakhand, India. No gambling was required to get the reward.
Fotofeeling/Getty Images/Westend61 RM
These PET scans show the normal distribution of opioid receptors in the human brain. A new study suggests ketamine may activate these receptors, raising concern it could be addictive.
Philippe Psaila/Science Source
Having more than one child is associated with a lower risk of Alzheimer's, research finds, as is starting menstruation earlier in life than average and menopause later.
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Several circular herpes virus particles are seen near a cell membrane. Roseola herpes virus causes a childhood illness marked by skin rashes and now has been found in brains with Alzheimer's disease.
Marines based in Okinawa, Japan, fire an M136 AT-4 rocket launcher as part of a weapons training exercise on the Kaneohe Bay Range Training Facility, in 2014.
Lance Cpl. Matthew Bragg/U.S. Marines/DVIDS