SPRINGFIELD, Mass. — A Springfield man has pleaded guilty to second-degree murder for beating a mother of seven to death in a dispute over drugs.The Republican newspaper (http://bit.ly/1IlQ5sO ) reports that Ronald Ruell Jr. was sentenced Tuesday in Hampden Superior Court to 25 years in prison for the February 2012 death of 38-year-old Judy Ramirez.Prosecutors say the two had been using cocaine together.