ByJohn S. McClenahen Although many of the U.S. manufacturing jobs lost in the wake of the 2001 recession won't return, there's an additional sign that the U.S. labor market is improving. The Conference Board's Help-Wanted Advertising Index increased to 39 in November 2003, the most recent month for which data are available. The index was at 37 in October. "This is the first rise of even this small amount since June," notes Ken Goldstein, an economist at the New York-based business research group. "The labor market is finally sparking to life." The Conference Board's index is based upon a survey of help-wanted advertising volume in 51 major newspapers across the United States.