OAKLAND — Citing concerns about public safety, city officials Friday canceled an anti-violence rally and concert expected to draw 300 to 400 teenagers and young adults to downtown Oakland. "Get Hyphy Against Violence," featuring nine musical acts and testimony from victims of violent crime, had been scheduled to take place today at City Hall Plaza, but did not have the required special event permit or adequate security, officials said. Police commanders said they were concerned that, without enough officers, the anti-violence rally could backfire and create a melee similar to one that erupted after the last Carijama festival, held on...