Bed RestHead-Down TiltWeightlessness SimulationWeightlessness CountermeasuresJuvenile DelinquencyRestEl SalvadorSocial ProblemsCardiovascular DeconditioningSocial IdentificationViolenceSpace FlightBedsCrimeFirearmsPeer GroupWeightlessnessHomicideLos AngelesOrthostatic IntoleranceLower Body Negative PressureStreet DrugsSocial ConformityCitiesBed OccupancySubstance-Related DisordersSupine PositionMuscular AtrophyAdolescent BehaviorRisk-TakingPlasma VolumeSocial BehaviorEarly AmbulationMuscle, SkeletalSmall-Area AnalysisExerciseHypotension, OrthostaticHispanic AmericansPregnancy-Associated Plasma Protein-AHypovolemiaTime FactorsMiocamycinVascular CapacitanceAggressionAmino Acids, EssentialBacteriophage muImmobilization