The Sensex at the Bombay Stock Exchange fell 79 points, or 0.5 per cent, to 17,411 in opening trade, this morning, as funds and retail investors offloaded positions ahead of the monthly settlement in the derivatives segment, amid weak Asian Bourses.Later, the Sensex recovered some lost ground, to stand a more modest 23 points, or 0.1 percent in negative territory, at 17,468 in afternoon deals, a short while ago. The 30-share Sensex had lost nearly 360 points in the previous four trading sessions.Other Asian markets in Japan, China, Indonesia, Hong Kong, Singapore, South Korea and Taiwan were down by between 0.2 percent and 1.6 percent, today, after data showed that Japan's retail sales declined 0.8 percent in July. The US Dow Jones Industrial Average had ended almost flat in yesterday's trade.