Donald Yukio Yamamoto is the former acting Assistant Secretary of State for African Affairs, U.S. Ambassador to Ethiopia and Principal Deputy Assistant Secretary within the Bureau of African Affairs. He was appointed by President George W. Bush in November, 2006, and presented his credentials to Ethiopian Prime Minister Meles Zenawi in Addis Ababa on December 6, 2006. Wikipedia*
On the C-SPAN Networks:
Donald Yamamoto has seven videos in the C-SPAN Video Library; the first appearance was a 2011 House Committee as a Deputy Assistant Secretary for the African Affairs of the Department of State.