Amid growing healthcare consolidation as Obamacare rolls out, UC Irvine and MemorialCare Health System have agreed to a partnership deal. The UC Board of Regents said Wednesday it has approved an affiliation between UC Irvine Health and MemorialCare, two major hospital systems in Southern California. It's not a merger and both will remain independent. In California and nationwide, many hospitals and physician groups are joining forces to improve their negotiating clout with employers and insurers. In particular, insurance companies have been narrowing their provider networks to hold down costs and big health systems don't want to be left out.