Stocks remained mixed early Wednesday afternoon as Apple's (AAPL) rebound tempered Boeing's (BA) sharp decline amid safety concerns with its new 787 Dreamliners. The Nasdaq rose 0.2%, the S&P 500 was flat and the Dow Jones industrial average dipped 0.2%. Volume was down 2% on the Nasdaq and was 4% lower on the NYSE compared with midday Tuesday. Apple rose 4%, regaining the key 500 mark in heavy volume and boosting the Nasdaq. But Boeing plunged