Ayman Taha, a Berkeley graduate who was described as athletic, a speaker of many languages, and a friend to all who met him, had only to write his dissertation to earn his PhD, his father said. But three years ago, Taha, a budding economist and the son of a Northern Virginia couple, Abdel-Rahman and Amal Taha, joined the Army to serve in the Special Forces. About a year ago, he was sent to Iraq. On Friday, as Staff Sgt. Ayman Taha, 31, was preparing a cache of munitions for demolition in the town of Balad, the explosives detonated and he...