Nurses at University of Illinois Hospital & Clinics have ended a four-day strike after reaching a tentative contract agreement with UI Health late Saturday night. The nurses began their strike Nov. 13, with no set end date. The strike was the second one since August, when the nurses’ last contract expired. About 1,700 nurses are part of the Illinois Nurses Association unit that went on strike. The nurses returned to work Sunday morning. The tentative four-year contract agreement reached late Saturday night includes improved hospital safety protocols, higher wages and nurse input into staffing decisions, the union said in a news release.