Sgt. Samantha Nosek, U.S. Army Center for Health Promotion and Preventive Medicine physical science technician, adds acid to water to determine the alkalinity of the sample at the Landstuhl Regional Medical Center, Germany, Oct. 10. The USACHPPM provides worldwide scientific expertise and services in clinical and field preventive medicine, environmental and occupational health, health promotion and wellness, epidemiology and disease surveillance, toxicology, and related laboratory sciences. (U.S. Air Force photo/Airman 1st Class Marc I. Lane)