Advance Publications will sell The Star-Ledger of Newark unless a quarter of the full-time staff accepts buyouts by October and the mailer and driver unions accept new agreements. "Although we have implemented a variety of plans to reduce expenses and create new sources of revenue, we have been unable to offset the unprecedented decline in advertising revenue," Star-Ledger Publisher George Arwady told the staff of 750. He said the paper had already retained J.P. Morgan Chase to "help us plan a sale." Advance Publications said earlier this week it will close its Newhouse News Service in November.