Stocks marked another day of modest gains in mixed trade Wednesday. The Nasdaq led, boosted by chip and biotech stocks. The composite ended up 0.8% and nearer to its intraday high than the other major indexes. It was another sign that the Nasdaq is leading the current market uptrend. The NYSE composite and S&P 500 each added 0.5%. The Dow closed flat. Trading was slightly higher on the NYSE, but slipped on the Nasdaq. Stocks were stronger earlier