ByJohn S. McClenahen Although the U.S. Labor Department boasts that both the number of extended mass layoffs during 2003's fourth quarter and the number of workers losing their jobs were "sharply lower" than the numbers for 2002's final three months, last year's fourth-quarter numbers were higher than those for the previous quarter. The department's numbers show that employers laid off 359,085 workers during the fourth quarter last year as they took 1,956 actions to restructure, close plants, and end seasonal work. In the third quarter of last year, 300,901 workers were let go as 1,458 layoff "events" took place. The bottom line: 58,104 more workers lost their jobs during the fourth quarter of 2003 than during the third as the number of layoffs climbed by 498. Extended mass layoffs are those lasting at least 31 days and involving 50 or more individuals from a single establishment filing initial claims for unemployment insurance during a consecutive five-week period, according to the Labor Department.