Memorias de la zona tórrida: el naturalismo clásico y la «tropicalidad» americana en el Sumario de la natural historia de las Indias de Gonzalo Fernández de Oviedo (1526)

Este ensayo examina el papel que juega la «tropicalidad» en la taxonomía de la naturaleza y cultura americanas que ofrece Oviedo en el Sumario de la natural historia de las Indias (1526). Accediendo a los paradigmas científicos y técnicos que informan este tratado, se arguye que la construcción de las Indias como un lugar «tropical» distinto de la Europa mediterránea pero similar a las Indias Orientales, le sirve a Oviedo de un marco de referencia fundamental para representar la compleja otredad de lo americano y a la vez abordar un debate geopolítico sobre el derecho de la conquista.Este ensayo examina el papel que juega la «tropicalidad» en la taxonomía de la naturaleza y cultura americanas que ofrece Oviedo en el Sumario de la natural historia de las Indias (1526). Accediendo a los paradigmas científicos y técnicos que informan este tratado, se arguye que la construcción de las Indias como un lugar «tropical» distinto de la Europa mediterránea pero similar a las Indias Orientales, le sirve a Oviedo de un marco de referencia fundamental para representar la compleja otredad de lo americano y a la vez abordar un debate geopolítico sobre el derecho de la conquista

Structural asymmetry of the human cerebral cortex: Regional and between-subject variability of surface area, cortical thickness, and local gyrification

Structural asymmetry varies across individuals, brain regions, and metrics of cortical organization. The current study investigated regional differences in asymmetry of cortical surface area, thickness, and local gyrification, and the extent of between-subject variability in these metrics, in a sample of healthy young adults (N = 200). Between-subject variability in cortical structure may provide a means to assess the extent of biological flexibility or constraint of brain regions, and we explored the potential influence of this variability on the phenotypic expression of structural asymmetry. The findings demonstrate that structural asymmetries are nearly ubiquitous across the cortex, with differing regional organization for the three cortical metrics. This implies that there are multiple, only partially overlapping, maps of structural asymmetry. The results further indicate that the degree of asymmetry of a brain region can be predicted by the extent of the region’s between-subject variability. These findings provide evidence that reduced biological constraint promotes the expression of strong structural asymmetry

The Biota of Intermittent Rivers and Ephemeral Streams: Prokaryotes, Fungi, and Protozoans

Microbial diversity and function in intermittent rivers and ephemeral streams (IRES) are tightly linked to specific habitat availability and hydrological phases. The intensity and frequency of the different phases (especially drying and rewetting) affect community composition and key functions, mainly linked to biogeochemical processes. Resistance and resilience strategies are distinct among microorganism groups-bacteria, archaea, fungi, protozoans-and strongly depend on different types of microhabitat or refuge available. The biodiversity of prokaryotes in IRES is strongly affected by hydrology but microhabitat conditions and type of benthic substrate significantly affect their community composition. Fungi are very sensitive to drying but use several refuges, including the terrestrial habitat, and resistance strategies. Protozoans show a wide range of survival strategies and several species can resist harsh conditions such as anoxia in drying pools. Thus, they become especially relevant for ecosystem functions when other organisms are inhibited. This sensitivity causes waves of microbial functions and biodiversity to covary with hydrological phases, potentially affecting ecosystem functioning and higher trophic levels. Microbially mediated functions in IRES are perhaps the most critical to freshwater ecosystem services such as nitrogen and carbon cycling. Therefore, efforts to manage and restore IRES will depend on improved understanding of hydrological controls on microbial communities and functions across space and time. © 2017 Copyrigh