What all this points to, says Peter Cappelli , director of Wharton s Center for Human Resources , is the emergence of a dramatically different labor market that is changing not just the way people are hired and fired, but also how they view their jobs, their employers and their careers. Speaking at a Nov. 19 executive education forum on “Managing in Tough Times: Perspectives on Leadership and Change,” Cappelli told executives in human resources and leadership development that changes in the labor market are taking place under conditions managers have never before faced  the need to downsize juxtaposed with the increasingly difficult task of recruiting new employees and retaining those who are already top performers. All this under the cloud of a now official recession and the events of September 11. “For those of us who study management,” Cappelli says, “it is a unique” convergence of challenges.…