The University of Iowa has started a disciplinary hearing that could lead to the firing of Malik E. Juweid, a radiology professor who is accused of sending “prejudiced, insulting, and inflammatory” e-mail messages to colleagues that call them anti-Arab and anti-Muslim. In an interview with the Associated Press, Mr. Juweid, who is Christian and was born in Jordan, said, “I feel that about 10 percent of my department employees are prejudiced, bigots, Arab-haters, and Muslim-haters. Thank God, 90 percent of people are decent people who are not like that.”