RALEIGH, N.C. (AP) North Carolina Gov. Roy Cooper has signed legislation that helps public schools rehire retired teachers in hard-to-fill classrooms and increases prison time for someone who uses a gun to assault a law enforcement officer.Cooper has announced he's enacted another dozen bills with his signature.One measure signed on Thursday will more than double the minimum prison sentence to roughly three years for someone convicted of a firearm-related assault on a police, correctional, probation or parole officer. Such crimes will become a more severe felony starting Dec. 1.Another new law offers a way to hire ex-teachers without harming their state retirement benefits. The teachers could work in low-performing schools and those with a high percentage of students from low-income families. Math and science teachers would get higher salaries.