(Hillsboro, OR)  --  An Oregon State Police trooper will be on probation for 18 months, after pleading guilty to an assault charge.  Senior Trooper James Duncan entered the plea to a misdemeanor count of fourth-degree assault, stemming from an incident involving his son.  Duncan was also ordered to avoid contact with his two children and undergo anger-management and parenting classes.  "The Oregonian" reports State Police will now conduct an internal inquiry into Duncan.