Stocks turned positive in early-afternoon trade Wednesday, after showing mixed action earlier in the session. The Dow Jones industrial average rose 0.5%, helped by IBM's (IBM) 5% rise on its upbeat quarterly report. The Nasdaq added 0.4%, while the S&P 500 edged up 0.1%. Volume is now tracking down slightly from Tuesday's levels. It had been up slightly in morning action. IBM's 5% jump in heavy turnover came after the tech services provider