Stocks continued to show modest losses and to hold near session lows in early-afternoon action Thursday, after giving up morning gains. The Nasdaq lost 0.5%, the Dow Jones industrial average 0.4% and the S&P 500 0.3%. Volume was tracking higher from Wednesday's levels. Apple (AAPL) dropped 1% in heavy turnover, falling further below its 200-day moving average. The stock has touched its lowest level since May 18, the session when it established a