Rising for the third straight session, the Sensex at the Bombay Stock Exchange gained 39 points, or 0.2 percent, to close at 18,558, today. The Nifty advanced 5 points, to 5,477.Stock markets in Japan, China, Hong Kong South Korea and Singapore ended mixed. The rupee weakened 110 paise, to close at 64.30 against the dollar.Gold fell 200 rupees, to 31,500 rupees per ten grams in Delhi. But silver climbed 470 rupees, to 54,000 rupees per kilo.And Brent crude oil futures rose to a near five-month high of about 112 dollars a barrel, while US crude climbed 38 cents, to 106.80 dollars a barrel.