Positive leader characteristics from high-speed video observations

Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values range from 0.3 to 6.0 x 10(5) ms(-1) with a mean of 2.7 x 10(5) ms(-1). Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.

The Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders: recruitment, assessment instruments, methods for the development of multicenter collaborative studies and preliminary results

OBJETIVO: Descrever o recrutamento de pacientes, instrumentos de avaliação, métodos para o desenvolvimento de estudos colaborativos multicêntricos e os resultados preliminares do Consórcio Brasileiro de Pesquisa em Transtornos do Espectro Obsessivo-Compulsivo, que inclui sete centros universitários. MÉTODO: Este estudo transversal incluiu entrevistas semi-estruturadas (dados sociodemográficos, histórico médico e psiquiátrico, curso da doença e diagnósticos psiquiátricos comórbidos) e instrumentos que avaliam os sintomas do transtorno obsessivo-compulsivo (Escala para Sintomas Obsessivo-Compulsivos de Yale-Brown e Escala Dimensional para Sintomas Obsessivo-Compulsivos de Yale-Brown), sintomas depressivos (Inventário de Depressão de Beck), sintomas ansiosos (Inventário de Ansiedade de Beck), fenômenos sensoriais (Escala de Fenômenos Sensoriais da Universidade de São Paulo), juízo crítico (Escala de Avaliação de Crenças de Brown), tiques (Escala de Gravidade Global de Tiques de Yale) e qualidade de vida (questionário genérico de avaliação de qualidade de vida, Medical Outcome Quality of Life Scale Short-form-36 e Escala de Avaliação Social). O treinamento dos avaliadores consistiu em assistir cinco entrevistas filmadas e entrevistar cinco pacientes junto com um pesquisador mais experiente, antes de entrevistar pacientes sozinhos. A confiabilidade entre todos os líderes de grupo para os instrumentos mais importantes (Structured Clinical Interview for DSM-IV, Dimensional Yale-Brown Obsessive-Compulsive Scale, Universidade de São Paulo Sensory Phenomena Scale ) foi medida após seis entrevistas completas. RESULTADOS: A confiabilidade entre avaliadores foi de 96%. Até março de 2008, 630 pacientes com transtorno obsessivo-compulsivo tinham sido sistematicamente avaliados. A média de idade (±SE) foi de 34,7 (±0,51), 56,3% eram do sexo feminino e 84,6% caucasianos. Os sintomas obsessivo-compulsivos mais prevalentes foram os de simetria e os de contaminação. As comorbidades psiquiátricas mais comuns foram depressão maior, ansiedade generalizada e transtorno de ansiedade social. O transtorno de controle de impulsos mais comum foi escoriação neurótica. CONCLUSÃO: Este consórcio de pesquisa, pioneiro no Brasil, permitiu delinear o perfil sociodemográfico, clínico e terapêutico do paciente com transtorno obsessivo-compulsivo em uma grande amostra clínica de pacientes. O Consórcio Brasileiro de Pesquisa em Transtornos do Espectro Obsessivo-Compulsivo estabeleceu uma importante rede de colaboração de investigação clínica padronizada sobre o transtorno obsessivo-compulsivo e pode abrir o caminho para projetos semelhantes destinados a integrar outros grupos de pesquisa no Brasil e em todo o mundo.

High-speed video observations of positive ground flashes produced by intracloud lightning

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ovariectomy by laparotomy, a video-assisted approach or a complete laparoscopic technique in Santa Ines sheep

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hybrid visual-driven decision support system in video monitor manufacturing

An intelligent system that emulates human decision behaviour based on visual data acquisition is proposed. The approach is useful in applications where images are used to supply information to specialists who will choose suitable actions. An artificial neural classifier aids a fuzzy decision support system to deal with uncertainty and imprecision present in available information. Advantages of both techniques are exploited complementarily. As an example, this method was applied in automatic focus checking and adjustment in video monitor manufacturing. Copyright © 2005 IFAC.

Video target tracking by using competitive neural networks

A target tracking algorithm able to identify the position and to pursuit moving targets in video digital sequences is proposed in this paper. The proposed approach aims to track moving targets inside the vision field of a digital camera. The position and trajectory of the target are identified by using a neural network presenting competitive learning technique. The winning neuron is trained to approximate to the target and, then, pursuit it. A digital camera provides a sequence of images and the algorithm process those frames in real time tracking the moving target. The algorithm is performed both with black and white and multi-colored images to simulate real world situations. Results show the effectiveness of the proposed algorithm, since the neurons tracked the moving targets even if there is no pre-processing image analysis. Single and multiple moving targets are followed in real time.

A video-based biometric authentication for e-learning web applications

In the last years there was an exponential growth in the offering of Web-enabled distance courses and in the number of enrolments in corporate and higher education using this modality. However, the lack of efficient mechanisms that assures user authentication in this sort of environment, in the system login as well as throughout his session, has been pointed out as a serious deficiency. Some studies have been led about possible biometric applications for web authentication. However, password based authentication still prevails. With the popularization of biometric enabled devices and resultant fall of prices for the collection of biometric traits, biometrics is reconsidered as a secure remote authentication form for web applications. In this work, the face recognition accuracy, captured on-line by a webcam in Internet environment, is investigated, simulating the natural interaction of a person in the context of a distance course environment. Partial results show that this technique can be successfully applied to confirm the presence of users throughout the course attendance in an educational distance course. An efficient client/server architecture is also proposed. © 2009 Springer Berlin Heidelberg.

Bothropstoxin-I reduces evoked acetylcholine release from rat motor nerve terminals: Radiochemical and real-time video-microscopy studies

Understanding the biological activity profile of the snake venom components is fundamental for improving the treatment of snakebite envenomings and may also contribute for the development of new potential therapeutic agents. In this work, we tested the effects of BthTX-I, a Lys49 PLA2 homologue from the Bothrops jararacussu snake venom. While this toxin induces conspicuous myonecrosis by a catalytically independent mechanism, a series of in vitro studies support the hypothesis that BthTX-I might also exert a neuromuscular blocking activity due to its ability to alter the integrity of muscle cell membranes. To gain insight into the mechanisms of this inhibitory neuromuscular effect, for the first time, the influence of BthTX-I on nerve-evoked ACh release was directly quantified by radiochemical and real-time video-microscopy methods. Our results show that the neuromuscular blockade produced by in vitro exposure to BthTX-I (1 μM) results from the summation of both pre- and postsynaptic effects. Modifications affecting the presynaptic apparatus were revealed by the significant reduction of nerve-evoked [3H]-ACh release; real-time measurements of transmitter exocytosis using the FM4-64 fluorescent dye fully supported radiochemical data. The postsynaptic effect of BthTX-I was characterized by typical histological alterations in the architecture of skeletal muscle fibers, increase in the outflow of the intracellular lactate dehydrogenase enzyme and progressive depolarization of the muscle resting membrane potential. In conclusion, these findings suggest that the neuromuscular blockade produced by BthTX-I results from transient depolarization of skeletal muscle fibers, consequent to its general membrane-destabilizing effect, and subsequent decrease of evoked ACh release from motor nerve terminals. © 2012 Elsevier Ltd.

A rank aggregation framework for video multimodal geocoding

This paper proposes a rank aggregation framework for video multimodal geocoding. Textual and visual descriptions associated with videos are used to define ranked lists. These ranked lists are later combined, and the resulting ranked list is used to define appropriate locations for videos. An architecture that implements the proposed framework is designed. In this architecture, there are specific modules for each modality (e.g, textual and visual) that can be developed and evolved independently. Another component is a data fusion module responsible for combining seamlessly the ranked lists defined for each modality. We have validated the proposed framework in the context of the MediaEval 2012 Placing Task, whose objective is to automatically assign geographical coordinates to videos. Obtained results show how our multimodal approach improves the geocoding results when compared to methods that rely on a single modality (either textual or visual descriptors). We also show that the proposed multimodal approach yields comparable results to the best submissions to the Placing Task in 2012 using no extra information besides the available development/training data. Another contribution of this work is related to the proposal of a new effectiveness evaluation measure. The proposed measure is based on distance scores that summarize how effective a designed/tested approach is, considering its overall result for a test dataset. © 2013 Springer Science+Business Media New York.

Ipsis video litteris: processos e procedimentos artísticos da escrita na televisão - videografia

Pós-graduação em Artes - IA

Curva de aprendizado da ovariohisterectomia video-assistida e da miniceliotomia associada à técnica do gancho de snook em gatas (Felis catus, Linnaeus, 1758)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Instrumento nuevo en el análisis social: ENTRE-RIELES": etapas y desarrollo de una experiencia en video interdisciplinaria"

Incluye Bibliografía

Entre Rieles: una experiencia interdisciplinaria en video sobre juventud popular urbana

Incluye Bibliografía

Estudo comparativo entre as técnicas de video-toracoscopia e toracotomia para fenestração de disco intervertebral em cães

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)