(Portland, OR)  --  Police are searching for a National Guardsman reported missing in Southeast Portland.  Marty Nance has been missing since last Saturday, when he failed to show up for weekend duties at the Portland Air Base.  Family and friends say they found his rental car in the Sellwood neighborhood with his cell phone still in it.  Anyone with information on his whereabouts is urged to call the Clackamas County Sheriff's Office.