A closely watched index of future U.S. economic activity rose on Thursday, reversing five months of declines, but the leading economic indicators are still down significantly from a year ago, fueling fears of a recession. The Conference Board, a business-financed research organization, said its forecast of future economic activity rose 0.1 percent in March, compared to a 0.3 percent drop in February. The increase was smaller than analysts had expected. The index is designed to forecast economic activity in the next three to six months, based on 10 economic components. The Conference Board said another of its indexes, which measures current economic activity, also has deteriorated in recent months, with weakness becoming more widespread among the components of both indexes. “The current behavior of the composite indexes suggests economic weakness is likely to continue in the near term,” the organization said in a statement.