Police arrested a Poughkeepsie High School teacher today after she allegedly stabbed a co-worker on the job with a screwdriver. School officials say Renette Ricketts, of Poughkeepsie, stabbed Cynthia Glozier, of Rhinebeck, in the middle of a crowded hallway. They say the fight broke out on the second floor between third and fourth periods. Police arrested Ricketts at the school, but cannot confirm why the alleged attack took place. She has been charged with assault and criminal possession of a weapon. Glozier is listed in good condition at St. Francis Hospital in Poughkeepsie.