A man's planned explosive attack on a South Florida Jewish center was thwarted by the FBI through an undercover operation involving a dummy bomb, authorities said Monday. James Medina, 40, made his initial appearance in federal court Monday following his arrest last week in the alleged plot against the Aventura Turnberry Jewish Center, which includes a synagogue, school and meeting halls. Medina is charged with attempted use of a weapon of mass destruction, which carries a potential life prison sentence. Assistant U.S. Attorney Marc Anton said the FBI learned in March that Medina - a Muslim convert who said in...