Wall Street opens higher; Facebook limits gains on Nasdaq

The S&P 500 and the Dow were higher at the open on Thursday, with the benchmark index on track to snap a seven-day losing streak, although a fall in Facebook's shares capped gains on the Nasdaq. Facebook fell 4 percent to $122.25, a day after the social media giant warned that revenue growth would slow this quarter. The S&P 500 ended lower on Wednesday for a seventh straight session, its longest such streak in five years, as the Federal Reserve signaled it could hike interest rates in De