Nurses at Baystate Franklin Medical Center will call for a one-day strike against their hospital by the end of the week.  The announcement came Wednesday after a three-hour bargaining session.  It was the 26th time the two sides have met without results.  Negotiating unit member Donna Stern says the union came to the table prepared to hammer out a contract with management.  The union plans to send a letter to hospital administrators in the next few days, including the exact date and time of the potential strike.  During the one day strike, the hospital would have to bring in replacement nurses.