Petition for writ of certiorari to the United States Court of Appeals for the Eleventh Circuit granted limited to the following question: Whether the federal-sector provision of the Age Discrimination in Employment Act of 1967, which provides that personnel actions affecting agency employees aged 40 years or older shall be made free from any "discrimination based on age," 29 U.S.C. § 633a(a), requires a plaintiff to prove that age was a but-for cause of the challenged personnel action.