Members of Local 33, the graduate student teachers’ union, erected a shelter yesterday on Beinecke Plaza to call attention to their demand for the university to begin contract negotiations. Teaching assistants in eight academic departments voted to unionize in February; the university is seeking to overturn the decision of the regional office of the National Labor Relations Board that approved the union's novel strategy of organizing by department. Eight Local 33 leaders began a hunger strike yesterday, saying they will refuse food until Yale negotiates. A university statement called the hunger strike “unwarranted by the circumstances.”