Database: academic_minus_1_0
Question: return me the number of the papers of " H. V. Jagadish " containing keyword " User Study " .
SQL: select count ( distinct t2.title ) from publication_keyword_keyword as t1 join publication as t2 on t1.pid = t2.pid join writes as t3 on t2.pid = t3.pid join author as t4 on t3.aid = t4.aid where t4.name = 'h. v. jagadish' and t1.keyword = 'user study' ;