The Emory Healthcare system continues its aggressive expansion in the Atlanta market, as it finalized an agreement Thursday to bring Newton Medical Associates into its primary care network. Dr. Henry M. Patton, lead physician of Newton Associates, said the partnership is part of Emory's efforts to create an accountable care organization (ACO), a comprehensive healthcare system encouraged by the healthcare reform Affordable Care Act. At its heart, an ACO is designed to create partnerships of healthcare providers, such as hospitals, specialists and primary care doctors, with the goal of