Confusion and a lot of questions exist as to detonation and pre-ignition. Sometimes you hear mistaken terms like pre-detonation. Detonation is one phenomenon that is abnormal combustion. Pre-ignition is another phenomenon that is abnormal combustion.
From Wikipedia, the free encyclopedia. Martha Herbert is an American physician and assistant professor of neurology at Harvard Medical School and pediatric neurologist at Massachusetts General Hospital. Herbert is also director of the TRANSCEND program at the Athinoula A. Martinos Center for Biomedical Imaging.
And Iâm Sarah Long with People in America in VOA Special English. Today, we tell about a woman who worked to make a difference in peopleâs lives, Barbara Jordan. (THEME) VOICE ONE: Barbara Jordan was a lawyer, educator and member of Congress. She was well-known for her powerful, thoughtful speeches. During her long political career, Barbara Jordan worked for social change.