Wall Street closed slightly higher on Monday session amid upbeat mood among investors before the new U.S. Federal Reserve Chairwoman Janet Yellen testified before the House of Representatives on Tuesday. The Dow Jones industrial average rose 0.05% to 15,801.79, the Standard & Poor's 500 Index added 0.16% to 1,799.84 and the Nasdaq Composite index gained 0.54% to 4,148.17.