(Portland, OR)  --  One arrest is being reported, following a demonstration in Portland against the Ferguson grand jury decision.  The protesters gathered around three p.m. yesterday at the Portland Justice Center, and began marching through downtown at 5:30 p.m.  One person, who police say was a heckler and not a protester, was arrested.  KGW-TV reports police blocked off the on-ramp to I-405 at Burnside Street and Southwest 14th Avenue to keep protesters from walking onto the highway.