CUNY submitted a petition to the state’s Public Employment Relations Board calling for a mediator after it could not reach a contract with the Professional Staff Congress. The PSC, the union representing more than 25,000 staff and professors, are in their sixth year of negotiations with administration for a new contract. The last contract expired Oct. 19, 2010. Since then, there were 27 meetings between CUNY and the PSC. Rita Rodin, a spokesperson for CUNY, said the PSC rejected the first offer made on Nov. 4. The union rejected it because of the low salary increase. “CUNY is offering a six-year contract with raises totaling six percent and other non-economic benefits,” she said. CUNY’s petition…