In open court we affirm the judgments of the District Court for the Southern District of New York which dismissed the complaint against the defendants Clara Rinaldi, doing business under the firm name and style of Queens Truck Rental, and against Mack Trucks, Inc. because of a prior judgment dismissing a similar complaint pursuant to Rule 41(b) of the Federal Rules of Civil Procedure for failure to prosecute. The effect of such a dismissal, prescribed by the Rule itself, is a matter of federal law, Kern v. Hettinger, 303 F.2d 333 (2 Cir., 1962)