NEW YORK — The stock market is encouraged by the Fed’s latest improved assessment of the economy, but not enough to propel the Dow Jones industrial average past 10,000. Stocks have closed lower after the Fed’s economic statement Wednesday. The market initially blipped higher, bringing the Dow within 82 points of crossing 10,000 for the first time since October, but the average ended the day with a loss of 81. The Fed said the pace of economic activity has “picked up” since its last meeting in August. According to preliminary calculations, the Dow fell 81 to 9,748. The Standard & Poor’s 500 fell 11 to 1,060, while the Nasdaq composite fell 14 to 2,131. Losing stocks outnumbered winners by about 3-to-2 on the New York Stock Exchange, where volume came to 1.3 billion shares.