Lorimar said it signed a definitive agreement to acquire Bozell & Jacobs for about $40 million in cash and notes . . . Union Carbide said it will close its carbon products plant in Niagara Falls, N.Y., which employs 212 . . . Bell Helicopter Textron reported that, starting Wednesday, it will lay off 1,000 of its 2,700 production workers for eight days and another 800 employees for three weeks to conduct a complete inventory . . . Times Mirror filed a shelf offering of as much as $300 million of notes with the SEC.