RESUMEN
Examining how morphology, life history and physiology vary along environmental clines can reveal functional insight into adaptations to climate and thus inform predictions about evolutionary responses to global change. Widespread species occurring over latitudinal and altitudinal gradients in seasonal water availability are excellent systems for investigating multivariate adaptation to drought stress. Under common garden conditions, we characterized variation in 27 traits for 52 annual populations of Mimulus guttatus sampled from 10 altitudinal transects. We also assessed variation in the critical photoperiod for flowering and surveyed neutral genetic markers to control for demography when analyzing clinal patterns. Many drought escape (e.g. flowering time) and drought avoidance (e.g. specific leaf area, succulence) traits exhibited geographic or climatic clines, which often remained significant after accounting for population structure. Critical photoperiod and flowering time in glasshouse conditions followed distinct clinal patterns, indicating different aspects of seasonal phenology confer adaptation to unique agents of selection. Although escape and avoidance traits were negatively correlated range-wide, populations from sites with short growing seasons produced both early flowering and dehydration avoidance phenotypes. Our results highlight how abundant genetic variation in the component traits that build multivariate adaptations to drought stress provides flexibility for intraspecific adaptation to diverse climates.
Asunto(s)
Adaptación Fisiológica , Mimulus/fisiología , Estrés Fisiológico , Altitud , Evolución Biológica , Clima , Sequías , Ambiente , Flores/genética , Flores/fisiología , Flores/efectos de la radiación , Marcadores Genéticos/genética , Variación Genética , Mimulus/genética , Mimulus/efectos de la radiación , Fenotipo , Fotoperiodo , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Hojas de la Planta/efectos de la radiación , Estaciones del Año , Selección GenéticaRESUMEN
OBJECTIVE: This study aims to examine the use and safety of rifampin in the hospitalized infants. STUDY DESIGN: Observational study of clinical and laboratory adverse events among infants exposed to rifampin from 348 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012. RESULT: Overall, 2,500 infants received 4,279 courses of rifampin; mean gestational age was 27 weeks (5th, 95th percentile; 23, 36) and mean birth weight was 1,125 g (515; 2,830). Thrombocytopenia (121/1,000 infant days) and conjugated hyperbilirubinemia (25/1,000 infant days) were the most common laboratory adverse events. The most common clinical adverse events were medical necrotizing enterocolitis (64/2,500 infants, 3%) and seizure (60/2,500 infants, 2%). CONCLUSION: The overall incidence of adverse events among infants receiving rifampin appears low; however, additional studies to further evaluate safety and dosing of rifampin in this population are needed.