Petty Officer 2nd Class James C. Williamson, a 27-year-old Corpsman with Detachment B, Marine Wing Support Squadron 471, Marine Wing Support Group 47, 4th Marine Aircraft Wing, takes part in training to treat a heat casualty at site 50 near Marine Corps Air Station Yuma, Ariz., July 24. Marines and sailors with the unit are taking part in operation Javelin Thrust 2011, the Marine Corps’ largest training exercise in the United States. Williamson, a Gladwin, Mich., native provides medical support and training to Marines with his unit. - Petty Officer 2nd Class James C. Williamson, a 27-year-old Corpsman with Detachment B, Marine Wing Support Squadron 471, Marine Wing Support Group 47, 4th Marine Aircraft Wing, takes part in training to treat a heat casualty at site 50 near Marine Corps Air Station Yuma, Ariz., July 24. Marines and sailors with the unit are taking part in operation Javelin Thrust 2011, the Marine Corps’ largest training exercise in the United States. Williamson, a Gladwin, Mich., native provides medical support and training to Marines with his unit.