Beth Israel Deaconess Medical Center yesterday finalized a contract with its new CEO, Kevin Tabb, MD, who spent most of his adulthood in Israel before becoming a rising star at Stanford. He landed in Boston late Monday night and spent yesterday in meetings with managers and physician leaders and walking the floors of the Harvard teaching hospital, chatting with employees. Tabb, 47, who is the chief medical officer of Stanford Hospital and Clinics in California, will start his new job Oct. 17. The hospital did not disclose his salary or other terms of the agreement. Tabb said in an interview that it is too soon for him to lay out a detailed strategy, but that he expects to focus on preparing the hospital for the looming changes in the health care system, by improving efficiency and aligning with other hospitals and doctors groups. "This is the most competitive market in the country, and we need to be ready for change," Tabb said of the hospital. "It's clear to me we're going to have to form partnerships, that's one of the very first things I'll be working on."