On this edition of Africa 54, relatives of more than 300 girls abducted by gunmen from their boarding school in northwest Nigeria wait while security forces continue their search; At least two people are killed after security forces went to arrest Chad's opposition candidate Yaya Dillo at his home; The World Trade Organization's first female and first African director-general Ngozi Okonjo-Iweala begins work, ending a six-month leadership void.