(Portland, OR)  --  Bicyclists are worried they're being targeted after two tripwires were discovered in Northeast Portland.  Police say they responded to a report of a tripwire on Northeast Irving Street near 16th Avenue Monday morning.  Yesterday, a cyclist discovered another tripwire on a trail at Gateway Green Park.  It's not clear if the incidents are connected.  Portland Parks and Recreation spokesman Mark Ross tells KATU staff searched Gateway Green Park for additional traps yesterday but didn't find any.