Estructura de la comunidad de peces estuarinos en un hábitat con vegetación sumergida: variación estacional y nictémera

In order to analyze the temporal variations of an estuarine fish community in a submerged aquatic vegetation habitat, we completed six bi-monthly 24 h sampling cycles (using a seine net) over a 1-year period (1989-1990). A total of 17,105 individuals, corresponding to 66 fish species were captured. Species richness and diversity showed significant differences among months and its seasonal variation was mainly related to temperature and salinity. At diel scale, richness was higher at night and diversity during the day, although these parameters showed no significant differences between these two periods. A non-metric multidimensional scaling showed that the ordination of the samples was mainly related to seasonal variation, which showed significant differences in species composition between months (MANOVA). Despite a wide dominance of Anchoa mitchilli throughout the year, seasonal changes in species composition were due to the cyclical succession of populations of other species, primarily determined by their physiological tolerances and secondly, by feeding patterns. Although there were no significant changes between day and night in overall species abundance, cluster analyses showed that coincidentally in months with lower nocturnal light (new moon and first quarter), diurnal and nocturnal samples were clearly segregated, and associated alternatively with samples of twilight hours. During daytime, pelagic-planktophagous species were abundant and benthic-predatory ones in the night, whereas the most abundant species showed a twilight pattern of activity. So, seasonal changes in fish community are mainly related to physicochemical conditions, whereas diel variation was slightly related to the light/darkness cycle.Con el propósito de analizar las variaciones temporales en la comunidad de peces de un ambiente con vegetación sumergida, se realizaron seis ciclos nictémeros en un año (1989-1990) usando una red chinchorro. En total se recolectaron 17,105 individuos correspondientes a 66 especies. La riqueza y diversidad de especies difirieron significativamente entre meses y su variación estacional estuvo relacionada con la temperatura y la salinidad. En la escala nictémera, no existieron diferencias significativas en los valores de riqueza, diversidad y equidad obtenidos, entre la noche y el día. El análisis de escalamiento multidimensional mostró que las variaciones en las recolectas estuvieron relacionadas principalmente con las variaciones en el tiempo, existiendo cambios significativos (evidenciados por un análisis de varianza múltiple) en la composición de especies entre meses. Aunque existió una clara dominancia de Anchoa mitchilli durante todo el año, los cambios estacionales en la estructura de la comunidad se debieron a la sucesión cíclica en la abundancia de otras especies, determinada en primer grado por sus tolerancias fisiológicas y en segundo grado por patrones de alimentación. A pesar de que la comunidad no mostró diferencias significativas en su composición entre el día y la noche, los análisis de conglomerados demostraron que en ciertos meses existió una tendencia a separar las colectas diurnas de las nocturnas, asociadas cada una alternativamente a las realizadas en horas crepusculares, con una mayor captura de especies pelágicas-planctófagas durante el día y bentónicas-depredadoras en la noche, mientras que las más abundantes mostraron un comportamiento crepuscular. Así, los cambios estacionales en la comunidad están principalmente relacionados con las condiciones físico-químicas, mientras que a nivel nictémero, existe sólo una ligera influencia del ciclo de luz/oscuridad

The Potential Effect of Climate Change on the Distribution of Endemic Anurans from Mexico’s Tropical Dry Forest

Mexico is one of the richest countries in amphibian species (420 spp.), with a high level of endemism (69%). The order Anura represents the most diverse and widespread of the three extant amphibian orders (257 spp.). The anurofauna of Mexico’s tropical dry forest ecosystem host a high proportion of the species and endemism registered in the country. In terms of conservation, both dry forests and amphibians are at risk due to climate change because it is expected that as the temperature becomes higher and precipitation decreases, this vegetation type may experience water stress. We applied the MaxEnt algorithm to estimate the potential current and future (year 2070) geographic distribution patterns of 95 endemic Mexican anuran species inhabiting the country’s tropical dry forests by considering two representative concentration pathway scenarios (RCP4.5/RCP8.5) and analyzed the potential distributional pattern changes. The results indicated that overall, species would experience enough of a significant warming effect to cause a reduction in the original distribution area, with 44% of species losing an average of 50% of their original range (9 spp. in threatened category); additionally, 22% of the species in the dry forest ecosystem will experience an average increase of almost 50% in their original area, two species will lose more than 80% of their range, and one will disappear

International Nosocomial Infection Control Consortiu (INICC) report, data summary of 43 countries for 2007-2012. Device-associated module

We report the results of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2007-December 2012 in 503 intensive care units (ICUs) in Latin America, Asia, Africa, and Europe. During the 6-year study using the Centers for Disease Control and Prevention's (CDC) U.S. National Healthcare Safety Network (NHSN) definitions for device-associated health care–associated infection (DA-HAI), we collected prospective data from 605,310 patients hospitalized in the INICC's ICUs for an aggregate of 3,338,396 days. Although device utilization in the INICC's ICUs was similar to that reported from ICUs in the U.S. in the CDC's NHSN, rates of device-associated nosocomial infection were higher in the ICUs of the INICC hospitals: the pooled rate of central line–associated bloodstream infection in the INICC's ICUs, 4.9 per 1,000 central line days, is nearly 5-fold higher than the 0.9 per 1,000 central line days reported from comparable U.S. ICUs. The overall rate of ventilator-associated pneumonia was also higher (16.8 vs 1.1 per 1,000 ventilator days) as was the rate of catheter-associated urinary tract infection (5.5 vs 1.3 per 1,000 catheter days). Frequencies of resistance of Pseudomonas isolates to amikacin (42.8% vs 10%) and imipenem (42.4% vs 26.1%) and Klebsiella pneumoniae isolates to ceftazidime (71.2% vs 28.8%) and imipenem (19.6% vs 12.8%) were also higher in the INICC's ICUs compared with the ICUs of the CDC's NHSN