( users ( Ruth Karl ) roles ( MeetingLeader transactions (cancelMeeting removeAttendant) MeetingAttendant transactions (MinutesTaker) Clinician transactions (openMedicalRecord getPatientConsent) Patient transactions (accessMedicalHistory) Patient2 transactions () Patient3 ) subjects ( Ruth current role MeetingLeader authorized (MeetingLeader MeetingAttendant) John current role Clinician authorized () Julie current role MeetingAttendent ) users ( ) roles ( ) subjects ( ) )