(Portland, OR)  --  An 18-year-old is slated to spend five years behind bars after entering a guilty plea in an attack on a 70-year-old man.  Daniel Dorson pleaded guilty to one count of attempted assault on Larry Allen, an employee at the Portland Outdoor Store on Southwest 3rd Avenue.  Police say Allen was washing a sidewalk outside the store last July when he got into an argument with Dorson, who then hit Allen on the head with a skateboard.  Allen required multiple stitches following the attack.