Traders work at the New York Stock Exchange. Stocks fluctuated in a narrow range Wednesday, showing some signs of stability and recovery.

Washington ? The U.S. and Chinese stock exchanges returned to a semblance of normalcy Wednesday, but concerns about both economies linger following the worst global sell-off of stocks in more than five years.

Wall Street’s rebound Wednesday was quickly dubbed the Bernanke Rally after Federal Reserve Chairman Ben Bernanke. His relaxed, almost professorial, testimony before the House Budget Committee calmed jittery markets.

Bernanke told lawmakers that he expects a midyear return to solid economic growth despite new data showing that the U.S. economy has entered slow-growth mode. The Commerce Department on Wednesday revised economic growth for the fourth quarter of 2006 to a 2.2 percent annual rate, much slower than the 3.5 percent rate initially estimated last month.

“My view is, taking all the new data into account, there is really no material change in our expectations for the U.S. economy,” Bernanke said. He painted a largely positive economic picture, including an expected rebound in housing.

That sparked a morning rally on Wall Street before investors backed off later Wednesday, as the Dow Jones industrial average closed up 52.07 points, or 0.43 percent. The tech-heavy Nasdaq and S&P 500 also finished the day up, but none gained significant ground after the markets’ worst single day since trading after the 9/11 terrorist attacks resumed on Sept. 17, 2001.

U.S. investor sentiment was aided by a rebound in China’s Shanghai Composite Index. On Wednesday it clawed back nearly half of its 8.8 percent drop of a day earlier.

However, one day doesn’t a trend make on Wall Street

“Even when the earthquake is over, you see some aftershocks. So I think we can expect some volatility for a while now,” said David A. Wyss, chief economist for the rating agency Standard & Poors.