About 50 members and supporters of the Media Workers Union picketed the MediaNews-owned Mercury News over the shutdown of the paper’s advertising composing room and the outsourcing of its work to India, the Merc reported today. Guild executive officer Luther Jackson joined demonstrators Tuesday in a show of solidarity. A total of 28 jobs will be eliminated next week, said Gloria La Riva, president of the typographical sector of the Northern California Media Workers Union.