Is a jury instruction that was prejudicial and insufficient insufficient to convict a defendant in a sexual assault case?

Goldstein alleges that the district court erred by giving jury instructions with respect to Count 1 that were prejudicial and insufficient. The propriety of jury instructions is a question of law that we review de novo; the question is whether the challenged instruction misled the jury as to the correct legal standard or did not adequately inform the jury on the law. United States v. Pimentel, 346 F.3d 285, 301 (2d Cir.2003). We vacate the conviction only if the error was prejudicial; we will not disturb the judgment if the error was harmless. An erroneous instruction is harmless if it is clear beyond a reasonable doubt that a rational jury would have found the defendant guilty absent the error. Id. at 301-02.