Protesters turned up at a meeting of the Los Angeles Board of Education and shut down debate at a time when a teacher strike in the nation’s second-largest public school system seems increasingly likely. More than 50 adults and students went to the meeting late Monday and shouted at board members in support of teachers and their union, which has been negotiating for more than 1½ years with the Los Angeles Unified School District and its new superintendent, Austin Beutner, the Los Angeles Times reported.