Robert Heifetz, 68, an urban planning educator and peace activist. The son of the late silent screen starlet Florence Arto Vidor and violinist Jascha Heifetz, he was born in Los Angeles and educated at Claremont's private Webb School, William and Mary and Antioch colleges and Columbia University. Heifetz taught urban studies at the Hampton Institute, the University of Illinois and UC San Diego before joining the San Francisco State faculty. An avid sailor as well as activist, Heifetz taught sailing and worked with the Bay Area Peace Navy to protest militarization of the San Francisco Bay and, most recently, advertising on boat sails. In 1985, he was among 29 U.S. peace activists held captive on the Nicaraguan border by anti-Sandinista rebels. Heifetz was representing his Peace Navy in a trip along the San Juan River to protest U.S. military intervention in Central America. Heifetz was also active in the International Jewish Peace Union and the Jewish Issues Discussion Group. On April 7 in San Francisco of cancer.