Christine Peterson is retiring as director of Nebraska’s Department of Health and Human Services. Gov. Dave Heineman named Peterson to the job two years ago as part of a restructuring of the system. Peterson took over a much-criticized system, dealing immediately with an audit showing a sloppy bill collection system, poor accountability in the foster care system and deficiencies at the Beatrice State Developmental Center. Peterson will serve through January 2. No replacement for Peterson has been named.