Understanding the effects of predictability, duration, and spatial pattern of drying on benthic invertebrate assemblages in two contrasting intermittent streams.

In the present study, we examined the effects of different drying conditions on the composition, structure and function of benthic invertebrate assemblages. We approached this objective by comparing invertebrate assemblages in perennial and intermittent sites along two intermittent Mediterranean streams with contrasting predictability, duration, and spatial patterns of drying: Fuirosos (high predictability, short duration, downstream drying pattern) and Rogativa (low predictability, long duration, patchy drying pattern). Specifically, we quantified the contribution of individual taxa to those differences, the degree of nestedness, and shifts in the composition, structure and function of benthic invertebrate assemblages along flow intermittence gradients. We observed greater effects of drying on the benthic invertebrate composition in Fuirosos than in Rogativa, resulting in a higher dissimilarity of assemblages between perennial and intermittent sites, as well as a lower degree of nestedness. Furthermore, a higher number of biotic metrics related to richness, abundance and biological traits were significantly different between perennial and intermittent sites in Fuirosos, despite a shorter dry period compared to Rogativa. At the same time, slightly different responses were detected during post-drying (autumn) than pre-drying (spring) conditions in this stream. In Rogativa, shifts in benthic invertebrate assemblages along increasing gradients of flow intermittence were found for three metrics (Ephemeroptera, Plecoptera and Trichoptera (EPT) and Odonata, Coleoptera and Heteroptera (OCH) abundances and aerial active dispersal. Furthermore, we demonstrated that combined gradients of dry period duration and distance to nearest perennial reach can generate complex, and different, responses of benthic invertebrate assemblages, depending on the flow intermittence metric. Our study advances the notion that special attention should be paid to the predictability, duration and spatial patterns of drying in intermittent streams in order to disentangle the effects of drying on benthic invertebrate assemblages, in particular in areas subject to high spatial heterogeneity and temporal variability in drying conditions.

Recién nacido pretérmino con quilotórax congénito bilateral, una entidad infrecuente que amenaza la vida / Preterm newborn with bilateral congenital chylothorax, a rare life-threatening entity

RESUMEN El quilotórax corresponde a la acumulación de linfa en el espacio pleural. El diagnóstico se confirma por la presencia de quilomicrones en el líquido pleural, sin embargo en la práctica clínica se utilizan los criterios de Büttiker, para establecer el diagnóstico. El objetivo de esta publicación es presentar el caso de un recién nacido con quilotórax congénito bilateral, realizando una revisión actualizada del tema, que incentive la recolección de datos y la generación de guías nacionales para su abordaje estandarizado. Se trató de un recién nacido pretérmino, quien tras parto por cesárea presentó síndrome de distrés respiratorio, ameritó terapia temprana de surfactante logrando retiro de ventilación mecánica al día de vida, con posterior presentación de signos de dificultad respiratoria y hallazgo radiológico y ecográfico de derrame pleural bilateral. Se realizó toracentesis con citoquímico compatible con quilotórax. Nuevamente ameritó soporte ventilatorio invasivo, toracostomía cerrada bilateral y nutrición parenteral, con posterior evolución clínica satisfactoria. MÉD.UIS. 2017;30(1):87-92.

ABSTRACT Chylothorax refers to the accumulation of lymphatic fluid in the pleural space. Diagnosis is confirmed by the presence of chylomicrons in the pleural fluid, however in clinical practice Büttiker criteria are widely used. The aim of this publication is to present the case of a newborn with bilateral congenital chylothorax with an updated review of the literature that encourages data collection and generation of national guidelines for standardized approach. This was a newborn preterm, who after a cesarean delivery presented respiratory distress syndrome who required early surfactant therapy achieving withdrawal of mechanical ventilation on his first day, with subsequent presentation of signs of respiratory distress, and a radiological and ultrasound finding of bilateral pleural effusion. Thoracentesis was performed obtaining cytochemical compatible with chylothorax. Again required invasive ventilatory support, closed bilateral thoracostomy and parenteral nutrition, with a satisfactory clinical course. MÉD.UIS. 2017;30(1):87-92.