Rising for the second straight session, the Sensex at the Bombay Stock Exchange gained 128 points, or 0.7 percent, to close at a one-week high of 18,542, amid rising global markets, today. The Nifty at the National Stock Exchange added 35 points, or 0.6 percent, to 5,594.Stock markets in Japan, Hong Kong, South Korea and Singapore gained between 0.3 percent and 2 percent.