Galápagos tortoise stable isotope ecology and the 1850s Floreana Island Chelonoidis niger niger extinction.

A consequence of over 400 years of human exploitation of Galápagos tortoises (Chelonoidis niger ssp.) is the extinction of several subspecies and the decimation of others. As humans captured, killed, and/or removed tortoises for food, oil, museums, and zoos, they also colonized the archipelago resulting in the introduction of invasive plants, animals, and manipulated landscapes for farming, ranching, and infrastructure. Given current conservation and revitalization efforts for tortoises and their habitats, here we investigate nineteenth and twentieth century Galápagos tortoise dietary ecology using museum and archaeological specimens coupled with analysis of carbon (δ13Ccollagen and δ13Capatite), nitrogen (δ15N), hydrogen (δD) and oxygen (δ18Oapatite) stable isotopes and radiocarbon dating. We identify that Galápagos tortoise diets vary between and within islands over time, and that long-term anthropogenic impacts influenced change in tortoise stable isotope ecology by using 57 individual tortoises from 10 different subspecies collected between 1833 and 1967-a 134-year period. On lower elevation islands, which are often hotter and drier, tortoises tend to consume more C4 vegetation (cacti and grasses). Our research suggests human exploitation of tortoises and anthropogenic impacts on vegetation contributed to the extinction of the Floreana Island tortoise (C. n. niger) in the 1850s.

Hydrogen isotope assimilation and discrimination in green turtles.

Although hydrogen isotopes (δ2H) are commonly used as tracers of animal movement, minimal research has investigated the use of δ2H as a proxy to quantify resource and habitat use. While carbon and nitrogen are ultimately derived from a single source (food), the proportion of hydrogen in consumer tissues originates from two distinct sources: body water and food. Before hydrogen isotopes can be effectively used as a resource and habitat tracer, we need estimates of (net) discrimination factors (Δ2HNet) that account for the physiologically mediated differences in the δ2H values of animal tissues relative to that of the food and water sources they use to synthesize tissues. Here, we estimated Δ2HNet in captive green turtles (Chelonia mydas) by measuring the δ2H values of tissues (epidermis and blood components) and dietary macromolecules collected in two controlled feeding experiments. Tissue δ2H and Δ2HNet values varied systematically among tissues, with epidermis having higher δ2H and Δ2HNet values than blood components, which mirrors patterns between keratinaceous tissues (feathers, hair) and blood in birds and mammals. Serum/plasma of adult female green turtles had significantly lower δ2H values compared with juveniles, likely due to increased lipid mobilization associated with reproduction. This is the first study to quantify Δ2HNet values in a marine ectotherm, and we anticipate that our results will further refine the use of δ2H analysis to better understand animal resource and habitat use in marine ecosystems, especially coastal areas fueled by a combination of marine (e.g. micro/macroalgae and seagrass) and terrestrial (e.g. mangroves) primary production.

Criterios de ingreso al servicio de aislamiento utilizados por los pacientes antendidos durante el periodo de enero a septiembre del 2004 / Criteria of entrance to the service of isolation used by the patients taken care of during the period of january september of the 2004

El objetivo del trabajo es indagar sobre los criterios utilizados en la práctica para la selección en el ingreso de pacientes al sector de aislamiento. Del total de ingresos analizados los motivos estan dados por el alto riesgo de contraer infección que tienen ciertos pacientes como: neutropenicos, transplantados de organos, riñon y médula osea. Conocer los criterios de ingreso ayudará en la organizacion del servicio, planificar recursos humanos y materiales, detectar necesidades de capacitacion y formacion del personal del servicio

Criterios de ingreso al servicio de aislamiento utilizados por los pacientes antendidos durante el periodo de enero a septiembre del 2004 / Criteria of entrance to the service of isolation used by the patients taken care of during the period of january september of the 2004

El objetivo del trabajo es indagar sobre los criterios utilizados en la práctica para la selección en el ingreso de pacientes al sector de aislamiento. Del total de ingresos analizados los motivos estan dados por el alto riesgo de contraer infección que tienen ciertos pacientes como: neutropenicos, transplantados de organos, riñon y médula osea. Conocer los criterios de ingreso ayudará en la organizacion del servicio, planificar recursos humanos y materiales, detectar necesidades de capacitacion y formacion del personal del servicio