Stocks opened modestly higher Wednesday, though the enthusiasm quickly faded. A continued sell-off in artificial intelligence (AI) heavyweights and worries over a potential government shutdown weighed on sentiment, while some end-of-quarter profit taking likely created pressure on the three main indexes.At the close, the blue chip Dow Jones Industrial Average was down 0.4% at 46,121, the broader S&P 500 was off 0.3% at 6,637, and the tech-heavy Nasdaq Composite was 0.3% lower at 22,497. Still, the three ind ...