Stocks were mixed in early afternoon action Friday, as some made wide gains and losses that balanced out to a moderate advance for the major indexes. The Nasdaq held its 0.5% gain, despite Apple's (AAPL) surrendering of early gains. The Dow Jones industrial average and S&P 500 inched ahead, now up 0.4% each. Volume continued to weaken, down 12% on the Nasdaq and 8% lower on the NYSE compared with the same time Thursday. Travel stocks were among