U.S. Army Maj. Gen. Mark MacCarley, Training and Doctrine Command deputy chief of staff, joins Pvt. Justin Thompson, a CH-47 Chinook helicopter maintenance technician currently training at the 128th Aviation Brigade, to ceremonially cut a birthday cake in honor of the U.S. Army Reserve's 105th birthday at TRADOC Headquarters at Fort Eustis, Va., April 23, 2013. Per military tradition, the senior official joins the youngest Service member in garrison to cut the cake. Both Soldiers share service in the Army Reserve: MacCarley began his Army career as a Reserve officer in the Judge Advocate General's corps in 1983; and Thompson is a Reservist assigned to the 90th Aviation Support Battalion in Fort Worth, Texas. The Army Reserve was effectively formed April 23, 1908, when President Theodore Roosevelt signed into public law Senate Bill 1424, creating the Medical Reserve Corps. The corps became the Organized Reserve June 4, 1920, through the National Defense Act Amendments. (Department of Defense photo by Air Force Senior Airman Jason J. Brown/Released)