Some women still party as if invulnerable It's midnight at Pravda, a trendy Manhattan bar where graduate students from nearby New York University are jammed into leather booths. A group chants, ''Another vodka! Another vodka!" A young woman named Jovana is in the corner, kissing a young man she met hours earlier. Days after the brutal rape and murder of a 24-year-old graduate student from Boston who had been drinking at a bar two blocks away, the scene is notable for an absence of fear. ''It happens here," Barbara Klen, a 24-year-old NYU student, said of the slaying. ''It happens...