Robert J. DiNicola, 53, the architect of Zale Corp.'s return to profitability and industry leadership in the 1990s, returned Feb. 21 as chairman and chief executive officer of the world's largest jewelry retailer. Sources say he will probably stay in the posts he held from 1994 to 2000 for "the long term," possibly up to three to five years. He replaces Beryl B. Raff, his protégé and longtime colleague, who resigned as Zale's chairman and CEO on Feb. 12, six months after her appointment to those posts in September 2000. Because of Raff's resignation and DiNicola's pending return, Zale Corp. delayed release of its official second-quarter earnings, originally set for Feb. 14, until March 7. No other changes are expected for Zale Corp.'s other senior executives—Alan P. Shor, president and chief operating officer; Sue E. Grove, executive vice president and chief financial officer; an