U.S. Air Force Col. Mark Nielsen was accompanied by his wife Laurie as he assumed command of the 307th Medical Squadron at Barksdale Air Force Base, La., April 12, 2015. Col. Nielsen is returning to the 307th Medical Squadron after working at the U.S. Air Force Academy as Individual Mobilization Augmentee to the United States Air Force Academy Command Surgeon and to the Commander of the 10th Medical Group for the past two years. (U.S. Air Force photo by Master Sgt. Laura Siebert/Released)