By John S. McClenahen Merrill Lynch & Co., among the most bearish short-term forecasters, has revised its fourth-quarter GDP estimate dramatically upward. The New York-based securities firm now foresees the U.S. economy growing at an annual rate of 3.5% in the current (and final) quarter of 2004. Previously it predicted just a 2.5% rate of inflation-adjusted growth. Among the reasons given for the revision: a higher-than-expected 8% annual rate for capital investment during the fourth quarter. But Merrill is sticking with a real GDP growth rate of just 2.5% for the first quarter of 2005, in part because of what it characterizes as "the sharp slowing" in orders for durable goods.