Stocks turned positive to show slight gains in early-afternoon action Thursday. But overall the market has been little changed Thursday, taking a breather after two straight sessions of strong gains. The Nasdaq, S&P 500 and Dow Jones industrial average all edged up less than 0.1%. Each index had been slightly negative in morning trade. Volume continued to track down from Wednesday's levels across the board. H&E Equipment Services (HEES) jumped 6%