Optimal Path Maps on the GPU.

We introduce a new method for computing optimal path maps on the GPU using OpenGL shaders. Our method explores GPU rasterization as a way to propagate optimal costs on a polygonal 2D environment, producing optimal path maps which can efficiently be queried at run-time. Our method is implemented entirely with GPU shaders, does not require pre-computation, addresses optimal path maps with multiple points and line segments as sources, and introduces a new optimal path map concept not addressed before: maps with weights at vertices representing possible changes in traversal speed. The produced maps offer new capabilities not explored by previous navigation representations and at the same time address paths with global optimality, a characteristic which has been mostly neglected in animated virtual environments. The proposed path maps partition the input environment into the regions sharing a same parent point along the shortest path to the closest source, taking into account possible speed changes at vertices. The proposed approach is particularly suitable for the animation of multiple agents moving toward the entrances or exits of a virtual environment, a situation which is efficiently represented with the proposed path maps.

Drought-induced Amazonian wildfires instigate a decadal-scale disruption of forest carbon dynamics.

Drought-induced wildfires have increased in frequency and extent over the tropics. Yet, the long-term (greater than 10 years) responses of Amazonian lowland forests to fire disturbance are poorly known. To understand post-fire forest biomass dynamics, and to assess the time required for fire-affected forests to recover to pre-disturbance levels, we combined 16 single with 182 multiple forest census into a unique large-scale and long-term dataset across the Brazilian Amazonia. We quantified biomass, mortality and wood productivity of burned plots along a chronosequence of up to 31 years post-fire and compared to surrounding unburned plots measured simultaneously. Stem mortality and growth were assessed among functional groups. At the plot level, we found that fire-affected forests have biomass levels 24.8 ± 6.9% below the biomass value of unburned control plots after 31 years. This lower biomass state results from the elevated levels of biomass loss through mortality, which is not sufficiently compensated for by wood productivity (incremental growth + recruitment). At the stem level, we found major changes in mortality and growth rates up to 11 years post-fire. The post-fire stem mortality rates exceeded unburned control plots by 680% (i.e. greater than 40 cm diameter at breast height (DBH); 5-8 years since last fire) and 315% (i.e. greater than 0.7 g cm-3 wood density; 0.75-4 years since last fire). Our findings indicate that wildfires in humid tropical forests can significantly reduce forest biomass for decades by enhancing mortality rates of all trees, including large and high wood density trees, which store the largest amount of biomass in old-growth forests. This assessment of stem dynamics, therefore, demonstrates that wildfires slow down or stall the post-fire recovery of Amazonian forests.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Transtriquetral perihamate fracture-dislocation: case report.

The wrist is a region that is very vulnerable to injuries of the extremities. Among these injuries, fractures of the pyramidal bone (or triquetrum) in association with dislocation of the hamate and carpal instability are uncommon. They are generally correlated with high-energy trauma and may be associated with neurovascular deficits, muscle-tendon disorders, skin lesions or injuries to other carpal bones. Thus, in this report, one of these rare cases of transtriquetral perihamate fracture-dislocation with carpal instability is presented, diagnosed by means of radiography on the right wrist of the patient who presented pain, edema and limitation of flexion-extension of the carpus after trauma to the region. The stages of attending to the case are described, from the initial consultation to the surgical treatment and physiotherapy, which culminated in restoration of the strength and range of motion of the wrist.

O punho é uma região muito vulnerável a traumas de extremidade. Entre tais lesões, as fraturas do piramidal (ou triquetrum), associadas à luxação do hamato e à instabilidade carpal, são pouco frequentes. Geralmente relacionadas a traumatismos de alta energia, podem estar associadas a déficit neurovascular, miotendíneo, lesões de pele ou em outros ossos do carpo. Assim, neste relato, apresenta-se um desses casos raros de fratura-luxação transtriquetral peri-hamato com instabilidade carpal, diagnosticadas por radiografias do punho direito de um paciente que apresentava dor, edema e limitação da flexoextensão do carpo após trauma na região. As etapas do atendimento foram descritas desde a consulta inicial até o tratamento cirúrgico e a fisioterapia, que culminaram com a restauração da força e da amplitude de movimento do punho.

Transtriquetral perihamate fracture-dislocation: case report / Fratura-luxação transtriquetral peri-hamato: relato de caso

ABSTRACT The wrist is a region that is very vulnerable to injuries of the extremities. Among these injuries, fractures of the pyramidal bone (or triquetrum) in association with dislocation of the hamate and carpal instability are uncommon. They are generally correlated with high-energy trauma and may be associated with neurovascular deficits, muscle-tendon disorders, skin lesions or injuries to other carpal bones. Thus, in this report, one of these rare cases of transtriquetral perihamate fracture-dislocation with carpal instability is presented, diagnosed by means of radiography on the right wrist of the patient who presented pain, edema and limitation of flexion-extension of the carpus after trauma to the region. The stages of attending to the case are described, from the initial consultation to the surgical treatment and physiotherapy, which culminated in restoration of the strength and range of motion of the wrist.

RESUMO O punho é uma região muito vulnerável a traumas de extremidade. Entre tais lesões, as fraturas do piramidal (ou triquetrum), associadas à luxação do hamato e à instabilidade carpal, são pouco frequentes. Geralmente relacionadas a traumatismos de alta energia, podem estar associadas a déficit neurovascular, miotendíneo, lesões de pele ou em outros ossos do carpo. Assim, neste relato, apresenta-se um desses casos raros de fratura-luxação transtriquetral peri-hamato com instabilidade carpal, diagnosticadas por radiografias do punho direito de um paciente que apresentava dor, edema e limitação da flexoextensão do carpo após trauma na região. As etapas do atendimento foram descritas desde a consulta inicial até o tratamento cirúrgico e a fisioterapia, que culminaram com a restauração da força e da amplitude de movimento do punho.

Avaliação da exposição humana ao mercúrio na região norte de Mato Grosso, Amazônia Legal / Human exposure assessment to mecury in the northern region of Mato Grosso, legal Amazon

Este artigo apresenta o atual cenário de exposição ao mercúrio na região norte de Mato Grosso, através da comparação da magnitude da exposição em diferentes municípios, ambos com hábitos alimentares de grande consumo de peixes oriundos de rio e piscicultura. O declínio da atividade garimpeira deixou um extensivo passivo ambiental na região, que vem contribuindo para o aumento da carga de mercúrio na bacia Amazônica. As autoridades locais têm encorajado as comunidades para o desenvolvimento da atividade de piscicultura, como uma nova opção socioeconômica para a região. Para piscicultores, uma das principais preocupações é a possibilidade de contaminação por mercúrio, advinda das áreas abandonadas pelos garimpeiros. A presente avaliação da exposição na região considerou as espécies de peixe mais consumidas pela população local, originárias dos rios e das pisciculturas da região. Os resultados mostraram que as doses de mercúrio variaram de 0,01 μg/kg/d a 3,9 μg/kg/d e indicaram que 82 porcento dos peixes de pisciculturas apresentaram níveis de mercúrio dentro do recomendado pela OMS para o consumo humano, isto é, abaixo de 0,3 μg/kg. Todavia, o consumo de peixes piscívoros de rios representa risco para alguns grupos das comunidades locais. Os resultados desse estudo visam contribuir para que os tomadores de decisão e os representantes das lideranças locais considerem as medidas de proteção da população pautados na avaliação de risco à saúde humana.