Stocks fell slightly at Tuesday’s opening bell as the bulls take a breather from Monday’s big day and Wall Street braces for a report on the U.S. service sector and testimony from Fed chief Ben Bernanke. Today’s Markets As of 9:32 a.m. EDT, the Dow Jones Industrial Average slid 21.27 points, or 0.25%, to 8406.87, the S&P 500 fell 3.10 points, or 0.34%, to 904.14 and the Nas...