U.S. Air Force Lt. Col. Richard Degrosa, second from left, an emergency room doctor with the 86th Medical Group, instructs Airman to use a ultrasound machine in preparation for a simulated in-flight surgery aboard a C-17 Globemaster III aircraft during the Joint Readiness Training Center 14-03 field training exercise at Fort Polk, La., Jan. 17, 2014. The exercise provided military units and personnel with realistic pre-deployment training scenarios in all aspects of armed conflict.