Twin Cities hospitals late Tuesday night gave registered nurses a new contract proposal that included compromises on pension and staffing ratios, two key issues for the nurses. But the Minnesota Nurses Association rejected the offer in talks that lasted until about 1 a.m. Wednesday. No new talks are scheduled, said Maureen Schriner, spokeswoman for the hospitals. The nurses have called for a strike that is scheduled to begin at 7 a.m. on July 6.