NEW YORK (TheStreet) -- U.S. stocks were trading sideways to marginally higher at the open on Friday after a weaker-than-expected report on first-quarter gross domestic product. The Dow Jones Industrial Average up 19 points, or 0.1% , at 13,224. The S&P 500 was higher by 1.7 points, or 0.1%, at 1402 and the Nasdaq was just a touch higher at 3053. The major U.S.