Prospect Medical Holdings, a chain that owns hospitals, as well as more than 165 outpatient facilities, said ransomware hackers had breached its system. Sixteen hospitals and more than a hundred other medical facilities across the United States are offline after the largest cyberattack on a U.S. hospital system since last year. Prospect Medical Holdings, a chain that owns hospitals, as well as more than 165 outpatient facilities, in California, Connecticut, Pennsylvania and Rhode Island has taken its main computer network offline, a spokesperson said Friday. The company first took its national computer systems offline Tuesday after discovering a ransomware attack,...