The YES Prep board finalized a decision Thursday to halt plans to expand to Memphis, cancelling a two-year pledge to operate its Houston-born charter schools in the troubled city. YES Prep's chief executive officer Jason Bernal had recommended ending the project, worried about low student enrollment, long-term funding and a less friendly political climate. The charter school network, named the nation's best in 2012, had planned to operate six campuses in Tennessee's new special district for struggling schools. The decision to abandon those plans comes as Texas lawmakers are considering whether to launch a similar "opportunity school district," which would put repeatedly low-performing schools under control of the state.