Stocks continued to show moderate gains at midafternoon Friday, putting the Nasdaq and S&P 500 on pace for their sixth straight weekly advances. The Nasdaq rose 1%, while the S&P 500 added 0.5%. The Dow Jones industrial average tacked on 0.3%. Volume in the stock market today was tracking down from Thursday's levels across the board. For the week, the Nasdaq and S&P 500 are set for advances of about 0.5% and 0.3%, respectively. The Dow is showing