Nearly 400 students from a dozen high schools in San Joaquin County will be vying for various awards at the 31st annual Academic Decathlon competition.Among the competitors will be 22 students from Manteca High, 22 students from Lathrop High School, and nine students from Ripon High. Other schools competing are Delta Charter of New Jerusalem School District in Tracy, Escalon High, Tracy High and West High (also in Tracy), Edison, Lincoln, McNair, Middle College, and Stockton Early College Academy. Guest teams this year are from Gilroy Early College Academy and Mountain View High from Santa Clara County.The theme of this year’s competition is The Age of Empire.The Manteca High School team placed third in the academic decathlon last year.