The Act became effective upon signature by the President on October 27, 1986. See 21 U.S.C. § 960; Beltre v. United States, 715 F. Supp. 606, 608 (S.D.N.Y. 1989). A sentence imposed pursuant to a law in effect at the time of the offense does not violate the ex post facto prohibition of the Constitution. Cf. Weaver v. Graham, 450 U.S. 24, 101 S.Ct. 960, 67 L.Ed.2d 17 (1981).