18thcentury 19thcentury 20thcentury agriculturallaborers automobiles california citrusfruitindustry cityandtownlife communitydevelopment economicconditions employment ethnicidentity ethnicrelations history indiansofnorthamerica interculturalcommunication julian mexicanamericans naturalhistory natureconservation seguracamacho socialaspects socialchange socialconditions suicidalbehavior unitedstates urbanecology(sociology) whites workingclass