IMPORTANCE OF RESERVOIRS FOR WATERBIRDS IN SEMI‐ARID BRAZIL

ABSTRACT ∙ To investigate the value of water reservoirs for waterbirds in semi‐arid lands, we studied the waterbird community in semi‐arid of Paraíba, Brazil, and compared the results with other assemblages both in semi‐arid and humid regions of Neotropics. Birds were counted during 15 months in 12 reservoirs belonging to the Piranhas‐Açu River basin. We counted 4111 waterbirds and recorded 36 species. The most abundant species, such as Wattled Jacana (Jacana jacana) and Common Gallinule (Gallinula galeata), were strongly tied to aquatic vegetation. All species have wide distribution, far beyond the borders of the semi‐arid region. Abundance and richness of waterbirds in Paraíba are lower than in more humid regions of Neotropics. Species composition in all semi‐arid sites studied seems to be a reduced version of assemblages in surrounding humid regions. Nevertheless, reservoirs may become important alternatives as feeding and breeding sites where the natural environments are insufficient to sustain waterbird populations. RESUMO ∙ A importância dos açudes para as aves aquáticas no semiárido brasileiro Para investigar a importância de açudes para aves aquáticas em regiões semiáridas, estudamos a comunidade de aves no semiárido da Paraíba, Brasil, e comparamos os resultados com outras assembleias em regiões semiáridas e úmidas dos neotrópicos. Durante 15 meses foram realizados censos da avifauna em 12 açudes na bacia do rio Piranhas‐Açu. Foram registradas 4111 aves e 36 espécies. As espécies mais abundantes, como a Jaçanã (Jacana jacana) e a Galinha‐d’água (Gallinula galeata), foram associadas às macrófitas. Todas as espécies possuem vasta distribuição geográfica, ultrapassando as fronteiras da região semiárida. A abundância e a riqueza foram menores que aquelas encontradas em regiões úmidas. A composição de espécies nas regiões semiáridas estudadas compreende uma versão reduzida das assembleias das regiões úmidas. Todavia, os açudes podem se tornar alternativas importantes como locais de alimentação e reprodução onde os ambientes naturais são insuficientes para manter as populações de aves

Scale-Free Dynamics in Animal Groups and Brain Networks

Collective phenomena fascinate by the emergence of order in systems composed of a myriad of small entities. They are ubiquitous in nature and can be found over a vast range of scales in physical and biological systems. Their key feature is the seemingly effortless emergence of adaptive collective behavior that cannot be trivially explained by the properties of the system´s individual components. This perspective focuses on recent insights into the similarities of correlations for two apparently disparate phenomena: flocking in animal groups and neuronal ensemble activity in the brain. We first will summarize findings on the spontaneous organization in bird flocks and macro-scale human brain activity utilizing correlation functions and insights from critical dynamics. We then will discuss recent experimental findings that apply these approaches to the collective response of neurons to visual and motor processing, i.e., to local perturbations of neuronal networks at the meso- and microscale. We show how scale-free correlation functions capture the collective organization of neuronal avalanches in evoked neuronal populations in nonhuman primates and between neurons during visual processing in rodents. These experimental findings suggest that the coherent collective neural activity observed at scales much larger than the length of the direct neuronal interactions is demonstrative of a phase transition and we discuss the experimental support for either discontinuous or continuous phase transitions. We conclude that at or near a phase-transition neuronal information can propagate in the brain with similar efficiency as proposed to occur in the collective adaptive response observed in some animal groups.Fil: Ribeiro, Tiago L.. National Institute Of Mental Health; Estados UnidosFil: Chialvo, Dante Renato. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Físicas. - Universidad Nacional de San Martín. Instituto de Ciencias Físicas; Argentina. Center for Complex Systems & Brain Sciences; ArgentinaFil: Plenz, Dietmar. National Institute Of Mental Health; Estados Unido

Gravitational form factors and decoupling in 2D

We calculate and analyse non-local gravitational form factors induced by quantum matter fields in curved two-dimensional space. The calculations are performed for scalars, spinors and massive vectors by means of the covariant heat kernel method up to the second order in the curvature and confirmed using Feynman diagrams. The analysis of the ultraviolet (UV) limit reveals a generalized "running" form of the Polyakov action for a nonminimal scalar field and the usual Polyakov action in the conformally invariant cases. In the infrared (IR) we establish the gravitational decoupling theorem, which can be seen directly from the form factors or from the physical beta function for fields of any spin.Comment: 19 pages, v2: fixed corrupted label

Monitorização do processo de condução e alertas baseados no contexto

Motivação e visão geral do sistema: A fadiga é considerada como um dos principais fatores responsável pela sinistralidade rodoviária. Uma agência norte-americana estimou, em 2013, que condutores com sonolência causada pela fadiga provocaram mais de 70 mil acidentes, resultando mais de 40 mil feridos e cerca de 800 mortos. 4 Tipicamente, para realizar a deteção destes aspetos é realizado processamento de imagem, como por exemplo, da retina. Porém, é possível utilizar outras abordagens, nomeadamente os sinais fisiológicos como é feito pelo Cardiowheel. O CardioWheel é um sistema embebido integrável em automóveis, tem como objetivo detetar automaticamente estados de fadiga e a identidade biométrica. Para tal é medido no volante um elemento biométrico do condutor, o sinal cardíaco, e emitidos alertas de fadiga para o exterior através de comunicações por GPRS.info:eu-repo/semantics/publishedVersio

Spike Avalanches Exhibit Universal Dynamics across the Sleep-Wake Cycle

Scale-invariant neuronal avalanches have been observed in cell cultures and slices as well as anesthetized and awake brains, suggesting that the brain operates near criticality, i.e. within a narrow margin between avalanche propagation and extinction. In theory, criticality provides many desirable features for the behaving brain, optimizing computational capabilities, information transmission, sensitivity to sensory stimuli and size of memory repertoires. However, a thorough characterization of neuronal avalanches in freely-behaving (FB) animals is still missing, thus raising doubts about their relevance for brain function. To address this issue, we employed chronically implanted multielectrode arrays (MEA) to record avalanches of spikes from the cerebral cortex (V1 and S1) and hippocampus (HP) of 14 rats, as they spontaneously traversed the wake-sleep cycle, explored novel objects or were subjected to anesthesia (AN). We then modeled spike avalanches to evaluate the impact of sparse MEA sampling on their statistics. We found that the size distribution of spike avalanches are well fit by lognormal distributions in FB animals, and by truncated power laws in the AN group. The FB data are also characterized by multiple key features compatible with criticality in the temporal domain, such as 1/f spectra and long-term correlations as measured by detrended fluctuation analysis. These signatures are very stable across waking, slow-wave sleep and rapid-eye-movement sleep, but collapse during anesthesia. Likewise, waiting time distributions obey a single scaling function during all natural behavioral states, but not during anesthesia. Results are equivalent for neuronal ensembles recorded from V1, S1 and HP. Altogether, the data provide a comprehensive link between behavior and brain criticality, revealing a unique scale-invariant regime of spike avalanches across all major behaviors.Comment: 14 pages, 9 figures, supporting material included (published in Plos One