It's not new news that the community health care mainstay Methodist Hospital is now USC Arcadia Hospital. The billboard that greets you as you enter the San Gabriel Valley off the 710 Freeway in Pasadena makes you well aware of USC's growing presence farther east of Los Angeles city. But this week, hospital, university, and elected officials christened the partnership that they say will keep the hospital alive in an age when the population is swelling — along with demand for healthcare services.