Black Hawk helicopters from 7th Battalion, 158th Aviation Regiment perform medical evacuations and deliver simulated victims of a nuclear detonation to Airmen from the 779th Medical Group for emergency hospital services in exercise Vibrant Response at Camp Atterbury Joint Maneuver Training Center in Southern Indiana July 29. The exercise, hosted by U. S. Army North, U. S. Northern Command's Joint Force Land Component Command, brings together approximately 9,000 military and civilian personnel from across the country to simulate the response to a terrorist attack in the United States.