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The city of Sampacho, situated in Rio IV department, center of Argentina, it is located in an intraplate region with proved historical and current seismic activity, where the level of seismicity, which is important, makes a low constant seismic geoamenace to the all region. It is worth mentioning that it was epicenter of two historical earthquakes (year 1934), considerated two of the most destructive ones within of the zone of reduced seismicity.In this paper characterizes preliminarily the Seismic Susceptibility in the sourrounding areas of Sampacho City, as a base for future studios of seismic microzoning and evaluation of Seismic-Risk. The following methodology emphatized the local Iithologic, geomorphologic and hydrologic factors, which may have an important incidence in the displacement of elastic wave front.It also defines five classes of susceptibility from superimpose of information levels (lithology and depth oflevel freatic), from wich the moderately low prevails. The areal distribution of them is presented in a preliminary Map of Seismic Susceptibility in digital support, being this one the first document developed on this theme for the region. La localidad de Sampacho, situada en el Departamento Rio Cuarto, Provincia de Córdoba, centro de la Republica Argentina, se encuentra emplazada en una región de intraplaca con probada actividad sísmica histórica y actual, donde el nivel de sismicidad, que es importante, pone en una constante geoamenaza sísmica a toda la región. Es de destacar que esta fue epicentro de dos terremotos históricos (año 1934), considerados dos de los mas destructores ocurridos dentro de la zona de sismicidad reducida.En el presente trabajo se caracterizo de manera preliminar la susceptibilidad sísmica en el entorno de la localidad de Sampacho, como base para futuros estudios de microzonificación sísmica y evaluación del riesgo sísmico. La metodología seguida hizo énfasis en el estudio de los factores litológicos, geomorfológicos e hidrológicos locales, los cuales pueden tener una importante incidencia en el desplazamiento del frente de ondas elásticas.Se definieron cinco clases de susceptibilidad a partir de la superposición de niveles de información litología y profundidad del nivel freático, de las cuales predomina la moderadamente baja. La distribución areal de las mismas se presenta en una carta de susceptibilidad sísmica preliminar en soporte digital, siendo este el primer documento sobre esta temática generado para la región.

We studied the putative effect of early life experience on the physiological flexibility of metabolic and osmoregulatory traits in the leaf-eared mouse, Phyllotis darwini, an altricial rodent inhabiting seasonal Mediterranean environments. Adult individuals were collected in central Chile and maintained in breeding pairs. Pups were isolated after weaning and acclimated to different temperatures (cold or warm) and water availability (unrestricted and restricted) until adulthood. Subsequently, individuals were re-acclimated to the opposite treatment. Rodents reared in the warm and subjected to water restriction had lower basal metabolic rate (BMR), total evaporative water loss (TEWL) and body mass (Mb) compared with those developing in the cold treatment; nevertheless, individuals subjected to warm temperatures had greater relative medullary thickness (RMT) and urine concentrating ability (UCA). Cold-reared rodents re-acclimated to warm conditions exhibited physiological flexibility of metabolic traits; however, their osmoregulatory attributes did not vary. Conversely, warm-reared rodents re-acclimated to cold had reduced RMT and UCA, but the metabolic traits of these individuals did not change. These results suggest a trade-off between metabolic performance and renal capabilities that might hinder physiological acclimation. Our results support the hypothesis of ontogenetic dependence of short-term acclimation in osmoregulatory and metabolic traits in P. darwini. [ABSTRACT FROM AUTHOR]

Mammals exposed to low temperatures increase their metabolic rate to maintain constant body temperature and thus compensate for heat loss. This high and costly energetic demand can be mitigated through thermoregulatory behavior such as social grouping or huddling, which helps to decrease metabolic rate as function of the numbers of individuals grouped. Sustained low temperatures in endothermic animals produce changes over time in rates of energy expenditure, by means of phenotypic plasticity. However, the putative modulating effect that huddling exerts on the flexibility of the basal metabolic rate (BMR) due to thermal acclimation remains unknown. We determined BMR values in Octodon degus, an endemic Chilean rodent, after being acclimated to either 15 or 30°C during 60 days, both alone and in groups of three and five individuals. At 15°C, BMR of huddling individuals was 40% lower than that of animals housed alone. Moreover, infrared thermography revealed a significant increase in local surface temperatures in huddled animals. Furthermore, individual thermal conductance was lower in individuals acclimated to 15°C than to 30°C, but no differences were observed between single and grouped animals. Our results indicate that huddling prevents an increase in BMR when animals are acclimated to cold conditions and that this effect is proportional to the number of animals grouped. [ABSTRACT FROM AUTHOR]