The Orange County district attorney’s office, as expected, will appeal a judge’s extraordinary reversal last month of a jury’s murder conviction against an Anaheim woman, who claimed she suffered from postpartum psychosis when she ran over her 6-week-old son. In filing an appeal with the 4th District Court of Appeal, prosecutors said, they will argue that Superior Court Judge Robert R. Fitzgerald had no legal authority to acquit Sheryl Lynn Massip on the grounds of insanity after a jury had convicted her of second-degree murder in the killing of her colicky infant son. In addition, Fitzgerald’s action threatens to give judges greatly expanded power in criminal cases and to make juries “nothing more than an advisory board,” Deputy Dist. Atty. Tom Borris said.