Grandmother asked social service agency for partial custody. Relatives of a mentally troubled woman from Oakland who reported hearing voices before she allegedly threw her three young sons into the bay to die said Thursday they had tried unsuccessfully to persuade Alameda County social service workers to help them gain custody of the children. Members of the family of La-shuan Ternice Harris said they had argued that the 23-year-old woman was unstable and unfit to care for her boys -- 6-year-old Trayshaun Harris, 2-year-old Taronta Greely Jr. and 16-month-old Joshua Greely. They had given up trying by Wednesday, when Harris...