The Sensex at the Bombay Stock Exchange gained 79 points, or 0.5 per cent, to 17,471 in opening trade, this morning, on selective buying by funds and retail investors. Later, the Sensex remained firm, and stood 93 points in the green, at 17,485 in afternoon trade, a short while ago. The 30-share Sensex had lost nearly 150 points in the last two trading sessions.Other Asian markets in China, Japan, South Korea, Indonesia, Hong Kong and Singapore were trading mixed, after Chinese trade data pointed to more signs of stress in the global economy.