Mark Marinella rejoined State Street Research & Management Co., Boston, as chief investment officer for fixed income. He had been co-CIO for fixed income, but left last July to become CIO and head of fixed income at Columbia Management Group, New York. Mr. Marinella resigned from Columbia in April; his replacement there hasn't been named. At State Street Research, Mr. Marinella now will be sole CIO. Dan Strelow, with whom he shared the title, was named head of long-duration and structured products, a new position.