By Jonathan Stempel NEW YORK (Reuters) – Ghislaine Maxwell on Thursday formally appealed her conviction and 20-year prison sentence for helping the late financier Jeffrey Epstein sexually abuse underage girls over more than a decade. The British socialite’s notice of appeal was filed nine days after she was sentenced by U.S. Circuit Judge Alison Nathan in Manhattan. Nathan said the punishment reflected Maxwell’s “instrumental” role in the abuse, and the “incalculable” damage it caused to victims. Lawyers for Maxwell had argued that she was being scapegoated for Epstein’s crimes. Maxwell, 60, w…