Human impacts outpace natural processes in the Amazon.

Amazonian environments are being degraded by modern industrial and agricultural activities at a pace far above anything previously known, imperiling its vast biodiversity reserves and globally important ecosystem services. The most substantial threats come from regional deforestation, because of export market demands, and global climate change. The Amazon is currently perched to transition rapidly from a largely forested to a nonforested landscape. These changes are happening much too rapidly for Amazonian species, peoples, and ecosystems to respond adaptively. Policies to prevent the worst outcomes are known and must be enacted immediately. We now need political will and leadership to act on this information. To fail the Amazon is to fail the biosphere, and we fail to act at our peril.

Epiphyseal fragment as a predictive factor of failure in fixation of proximal fractures of the humerus.

INTRODUCTION: Fractures of the proximal humerus are frequent and are widely studied with regards to their treatment indications. The aim of this article is to establish a correlation between the size of the epiphyseal fragment in fractures of the proximal humerus and the probability of loss of reduction after a surgical procedure. METHODS: A total of 47 surgically treated proximal humeral fractures were reviewed. Preoperative CT scans were used to evaluate the size of the epiphyseal fragment of the fracture. Postoperative X-rays were analyzed to assess complications, especially loss of reductions. Mean age was 61 years old (29-91 years). RESULTS: In total, 42 shoulders were evaluated. The average size of the epiphyseal fragment was 38.3 mm (32-50 mm) the largest longitudinal length; and 19.9 mm (12-30 mm) the largest cross-sectional length. The most frequent complication observed was loss of reduction. The statistical analysis showed significance that patients with smaller cross-sectional size of the epiphyseal fragment presented more complications (p = 0.034), and based on the graph and ROC curve, a value of 15.5 mm was considered as the cutoff value for failure. CONCLUSION: A cross-sectional length of the epiphyseal fragment of less than 15.5 mm indicates a higher probability of loss of reduction in fractures of the proximal end of the humerus after extra-medullary osteosynthesis.

The changing course of the Amazon River in the Neogene: center stage for Neotropical diversification

We review geological evidence on the origin of the modern transcontinental Amazon River, and the paleogeographic history of riverine connections among the principal sedimentary basins of northern South America through the Neogene. Data are reviewed from new geochronological datasets using radiogenic and stable isotopes, and from traditional geochronological methods, including sedimentology, structural mapping, sonic and seismic logging, and biostratigraphy. The modern Amazon River and the continental-scale Amazon drainage basin were assembled during the late Miocene and Pliocene, via some of the largest purported river capture events in Earth history. Andean sediments are first recorded in the Amazon Fan at about 10.1-9.4 Ma, with a large increase in sedimentation at about 4.5 Ma. The transcontinental Amazon River therefore formed over a period of about 4.9-5.6 million years, by means of several river capture events. The origins of the modern Amazon River are hypothesized to be linked with that of mega-wetland landscapes of tropical South America (e.g. várzeas, pantanals, seasonally flooded savannahs). Mega-wetlands have persisted over about 10% northern South America under different configurations for >15 million years. Although the paleogeographic reconstructions presented are simplistic and coarse-grained, they are offered to inspire the collection and analysis of new sedimentological and geochronological datasets.(AU)

Este trabalho é uma revisão das evidências geológicas sobre a origem do moderno rio Amazonas transcontinental, e a história paleogeográfica das conexões ribeirinhas entre as principais bacias sedimentares do norte da América do Sul durante o Neógeno. São revisados novos conjuntos de dados geocronológicos usando isótopos radiogênicos e estáveis, e de métodos geocronológicos tradicionais, incluindo sedimentologia, mapeamento estrutural, exploração sísmica e bioestratigrafia. O atual rio Amazonas e sua bacia continental se formaram durante o final do Mioceno e do Plioceno, através de alguns dos maiores eventos de captura de rio na história da Terra. Os sedimentos andinos são registrados pela primeira vez no leque fluvial do Amazonas por volta de 10,1-9,4 Ma, com um grande aumento na sedimentação a cerca de 4,5 Ma. O rio Amazonas transcontinental, portanto, se formou durante um período de cerca de 4,9 a 5,6 milhões de anos, por meio de vários eventos de captura de rios. Acredita-se que as origens do moderno rio Amazonas estejam ligadas às paisagens de inundação da América do Sul tropical (por exemplo, várzeas, pantanais, savanas sazonalmente inundadas). As áreas pantanosas persistiram em cerca de 10% do norte da América do Sul sob diferentes configurações por mais de 15 milhões de anos. Embora as reconstruções paleogeográficas apresentadas sejam simplistas, elas são oferecidas para inspirar a coleta e análise de novos conjuntos de dados sedimentológicos e geocronológicos.(AU)