NIAGARA FALLS, N.Y. (AP) _ Since the Sept. 11 anniversary, more than 14,000 foreign visitors have been fingerprinted at U.S. border crossings and 179 have been arrested, Attorney General John Ashcroft said Thursd`y* Standing a few feet away from the roaring American Falls, Ashcroft called the entry-exit program now in place at ports of entry around the country ``a vital national security shield'' to winnow out potential terrorists. ``We are confronted now with a new adversary, one who enters our country quietly,'' Ashcroft said. ``They enter disguised in the form of business persons or tourists or students. ``The challenge we...