The chief operating officer for Alabama Public Television has resigned after two other top network executives were fired seven weeks ago. The 62-year-old Grantham says his resignation is expected to take effect at the end of August. Grantham says his resignation is in response to the June 12 firings of executive director Allan Pizzato, and deputy director and chief financial officer Pauline Howland. The Alabama Educational Television Commission, which runs APT, fired Pizzato and Howland because they said it wanted to change leadership. Grantham sent an open letter to Gov.