Exercising the new "strong mayor" powers, Miami-Dade Mayor Carlos Alvarez has removed three department heads, citing poor job performance. Forced out: Transit director Roosevelt Bradley and planning and zoning director Diane O'Quinn. Employee relations chief Donald Allen was demoted. Some county commissioners were angry over Alvarez's failure to advise them of his decision. Black leaders have rallied behind Bradley, who was one of the county's highest-ranking black officials.