Relation Brésil-Paraguay : la montée des tensions

Depuis l’arrivée au pouvoir de Fernando Lugo en août 2008, les tensions entre le Paraguay et son puissant voisin, le Brésil, vont croissantes. À l’origine de ces dissensions se trouvent les exactions commises par les paysans sans terre paraguayens à l’encontre des Brésiliens émigrés dans leur pays afin de cultiver du soja. Ce petit État enclavé compte plus de 300 000 paysans sans terre et la répartition la plus inégale au monde de la propriété terrienne. La renégociation du Traité d’Itaipú, qui dispose de l’électricité produite par le barrage binational du même nom, représente une autre pomme de discorde entre les deux voisins. C’est que le Paraguay considère injuste d’avoir à vendre son excédent énergétique exclusivement au Brésil, et ce, bien en deçà de sa valeur marchande. Cette chronique met en exergue la perspective paraguayenne de cette relation ainsi que les développements récents dans les deux dossiers susmentionnés

Faunal exploitation at laguna condor site, Santa Cruz province, Argentina

El presente trabajo expone los resultados del análisis de la fauna recuperada en la localidad arqueológica de Laguna Cóndor, ubicada en el curso superior del río Gallegos en la zona de los Morros, Santa Cruz, Argentina. A pesar de la baja tasa de depositación ósea general, se registraron elevadas densidades puntuales de huesos muy fragmentados. Se identificó una alta diversidad de especies recuperadas aunque un único taxón fue explotado en forma intensa. El uso de la fauna estuvo dirigido fundamentalmente a la explotación de Lama guanicoe y, en forma ocasional, a recursos de bosque (Hippocamelus bisulcus) y a fauna introducida (Equus caballus). La evidencia refuerza la interpretación de Laguna Cóndor como un espacio explotado logísticamente en forma intensa y recurrente, pero por periodos relativamente breves hacia ca. 200 años AP.This paper presents the results of the analysis of faunal assemblages recovered at the archaeological locality of Laguna Condor, on the upper basin of the Gallegos River at the "Morros area", Santa Cruz, Argentina. Despite the low rate of bone deposition, high densities of highly fragmented bones were recorded. A high diversity of species was identified, although only one taxon was intensively exploited. The focus was on the exploitation of Lama guanicoe and, occasionally, forest resources (Hippocamelus bisulcus), and European fauna (Equus caballus). The evidence reinforces the interpretation of Laguna Condor as logistically, redundantly and intensively exploited place during short periods ca. 200 years AP.Fil: L'heureux, Gabriela Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; ArgentinaFil: Borrero, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; Argentin

Ecomorphological variations in the guanaco population of Patagonia (Argentina)

Este trabajo estudia los tamaños corporales de las poblaciones modernas de Lama guanicoe de Patagonia continental e insular (Argentina), a partir del análisis osteométrico de cuatro huesos largos delanteros (húmero, radiocúbito, metacarpo y primera falange). Se analizó una muestra de más de 100 individuos procedentes de las provincias de Río Negro (40°S), Santa Cruz (48-52°S) y Tierra del Fuego (53-54.5°S). Las variaciones morfológicas de los tamaños se evaluaron en función de las variables ecoambientales de: temperatura (máxima/mínima), precipitación (estival, invernal y anual), productividad primaria neta aérea (PPNA) e índice de vegetación diferencial normalizado (NDVI). Los datos fueron procesados mediante diferentes análisis uni y multivariados. Los resultados demostraron que, en una escala macroregional, se registra un gradiente clinal de los tamaños corporales de las poblaciones de guanacos (los individuos de Tierra del Fuego son significativamente más grandes que los de Santa Cruz y éstos más grandes que los de Río Negro). Todos los factores ecoambientales que se asocian fuertemente con los tamaños óseos (temperatura máxima, PPNA, NDVI) covarían en la región de estudio con la latitud. El patrón clinal observado es, en principio, consistente con las expectativas derivadas de la Regla de Bergmann. Igualmente las diferentes variables ambientales y biogeográficas que influyen sobre los patrones de los tamaños de los guanacos modernos de Patagonia, exponen que la relación entre el tamaño corporal y el ambiente es de naturaleza compleja y no se puede explicar de forma simple y directa por un solo factor.This paper studies the body sizes of modern, continental and insular Patagonian (Argentina) Lama guanicoe populations based on the osteometric analysis of four forelimb bones (humerus, radio-ulnae, metacarpus and first phalanx). A sample of more than 100 individuals from the Provinces of Río Negro (40°S), Santa Cruz (48-52°S) and Tierra del Fuego (53-54.5°S) were analyzed. The morphological size variations were evaluated considering the eco-environmental variables of temperature (maximum/ minimum), precipitation (summer, winter and annual), aerial net primary productivity (ANPP) and normalized difference vegetation index (NDVI). The data was analyzed using a number of uni and multivariate statistical models. The results show that, at a macro-regional scale, there was a clinal variation in the body sizes of guanaco populations (with individuals from Tierra del Fuego being significantly bigger than those from Santa Cruz, with the latter in turn being larger than those from Río Negro). All eco-environmental factors strongly associated with bone sizes (maximum temperature, ANPP, NDVI) co-vary, in the study region depending on latitude. The clinal pattern observed was, in principle, consistent with the expectations of Bergmann’s Rule. Also different environmental and biogeographic variables influenced the size patterns of modern Patagonian guanacos, thereby underscoring that the relationship between body size and environment is of a complex nature - and cannot be explained simply and directly by a single factor.Fil: L'heureux, Gabriela Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; ArgentinaFil: Cornaglia Fernández, Jimena. Universidad Nacional de Rosario. Facultad de Humanidades y Artes. Escuela de Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Feature-Binding Errors After Eye Movements and Shifts of Attention

When people move their eyes, the eye-centered (retinotopic) locations of objects must be updated to maintain world-centered (spatiotopic) stability. Here, we demonstrated that the attentional-updating process temporarily distorts the fundamental ability to bind object locations with their features. Subjects were simultaneously presented with four colors after a saccade—one in a precued spatiotopic target location—and were instructed to report the target’s color using a color wheel. Subjects’ reports were systematically shifted in color space toward the color of the distractor in the retinotopic location of the cue. Probabilistic modeling exposed both crude swapping errors and subtler feature mixing (as if the retinotopic color had blended into the spatiotopic percept). Additional experiments conducted without saccades revealed that the two types of errors stemmed from different attentional mechanisms (attention shifting vs. splitting). Feature mixing not only reflects a new perceptual phenomenon, but also provides novel insight into how attention is remapped across saccades.National Institutes of Health (U.S.) (Grant R01-EY13455

Sites géologiques touristiques en Abitibi-Témiscamigue

Les Cahiers présentent ici les résultats d'un projet de recherche conduit par un groupe d'étudiants du Collège de l'Abitibi-Témiscamingue au cours de l'été de 1983. Tout au long de ces quelque cent pages, les auteurs nous invitent à découvrir dix sites géologiques de la région, choisis pour leur beauté et l'intérêt qu'ils sauront susciter auprès des touristes. Des photos couleur, des cartes et des croquis viennent agrémenter un texte déjà très éclairant par lui-même, et le tout ainsi formé se présente comme une invitation à la découverte, un défi nouveau pour une nouvelle génération de touristes. «Sites géologiques touristiques en Abitibi-Témiscamingue» constitue donc une première pour le monde touristique régional et sans doute sera-t-il reçu comme une bouffée d'air frais dans les bureaux et kiosques des nombreuses associations vouées au développement du tourisme en Abitibi-Témiscamingue

A Tropospheric Assessment of the ERA-40, NCEP, and JRA-25 Global Reanalyses in the Polar Regions

The reliability of the global reanalyses in the polar regions is investigated. The overview stems from an April 2006 Scientific Committee on Antarctic Research (SCAR) workshop on the performance of global reanalyses in high latitudes held at the British Antarctic Survey. Overall, the skill is much higher in the Arctic than the Antarctic, where the reanalyses are only reliable in the summer months prior to the modern satellite era. In the Antarctic, large circulation differences between the reanalyses are found primarily before 1979, when vast quantities of satellite sounding data started to be assimilated. Specifically for ERA-40, this data discontinuity creates a marked jump in Antarctic snow accumulation, especially at high elevations. In the Arctic, the largest differences are related to the reanalyses depiction of clouds and their associated radiation impacts; ERA-40 captures the cloud variability much better than NCEP1 and JRA-25, but the ERA-40 and JRA-25 clouds are too optically thin for shortwave radiation. To further contrast the reanalyses skill, cyclone tracking results are presented. In the Southern Hemisphere, cyclonic activity is markedly different between the reanalyses, where there are few matched cyclones prior to 1979. In comparison, only some of the weaker cyclones are not matched in the Northern Hemisphere from 1958-2001, again indicating the superior skill in this hemisphere. Although this manuscript focuses on deficiencies in the reanalyses, it is important to note that they are a powerful tool for climate studies in both polar regions when used with a recognition of their limitations

Studying minijets via the pTp_T dependence of two-particle correlation in azimuthal angle ϕ\phi

Following my previous proposal that two-particle correlation functions can be used to resolve the minijet contribution to particle production in minimum biased events of high energy hadronic interactions, I study the $p_T$ and energy dependence of the correlation. Using HIJING Monte Carlo model, it is found that the correlation $c(\phi_1,\phi_2)$ in azimuthal angle $\phi$ between two particles with $p_T>p_T^{cut}$ resembles much like two back-to-back jets as $p_T^{cut}$ increases at high colliding energies due to minijet production. It is shown that $c(0,0)-c(0,\pi)$, which is related to the relative fraction of particles from minijets, increases with energy. The background of the correlation for fixed $p_T^{cut}$ also grows with energy due to the increase of multiple minijet production. Application of this analysis to the study of jet quenching in ultrarelativistic heavy ion collisions is also discussed.Comment: 11 pages Latex text and 8 ps figures, LBL-3349