(Portland, OR)  --  The conviction of a man who was found guilty of trying to set off a bomb at a Christmas tree-lighting ceremony in downtown Portland will remain in place.  A panel of three federal appellate court judges has upheld the conviction of Mohamed Mohamud, who tried to detonate what turned out to be a fake bomb at Portland's Pioneer Courthouse Square in November 2010.  One of the judges wrote that while the government's conduct in the case was aggressive at times, it fell short of a due-process violation.  Mohamud was convicted of trying to use a weapon of mass destruction and was sentenced to 30 years in prison.