Structural MRI texture analysis for detecting Alzheimer's disease

Purpose:: Alzheimer’s disease (AD) has the highest worldwide prevalence of all neurodegenerative disorders, no cure, and low ratios of diagnosis accuracy at its early stage where treatments have some effect and can give some years of life quality to patients. This work aims to develop an automatic method to detect AD in 3 different stages, namely, control (CN), mild-cognitive impairment (MCI), and AD itself, using structural magnetic resonance imaging (sMRI). Methods:: A set of co-occurrence matrix and texture statistical measures (contrast, correlation, energy, homogeneity, entropy, variance, and standard deviation) were extracted from a two-level discrete wavelet transform decomposition of sMRI images. The discriminant capacity of the measures was analyzed and the most discriminant ones were selected to be used as features for feeding classical machine learning (cML) algorithms and a convolution neural network (CNN). Results:: The cML algorithms achieved the following classification accuracies: 93.3% for AD vs CN, 87.7% for AD vs MCI, 88.2% for CN vs MCI, and 75.3% for All vs All. The CNN achieved the following classification accuracies: 82.2% for AD vs CN, 75.4% for AD vs MCI, 83.8% for CN vs MCI, and 64% for All vs All. Conclusion:: In the evaluated cases, cML provided higher discrimination results than CNN. For the All vs All comparison, the proposedmethod surpasses by 4% the discrimination accuracy of the state-of-the-art methods that use structural MRI.info:eu-repo/semantics/publishedVersio

An Efficient Monte Carlo-based Probabilistic Time-Dependent Routing Calculation Targeting a Server-Side Car Navigation System

Incorporating speed probability distribution to the computation of the route planning in car navigation systems guarantees more accurate and precise responses. In this paper, we propose a novel approach for dynamically selecting the number of samples used for the Monte Carlo simulation to solve the Probabilistic Time-Dependent Routing (PTDR) problem, thus improving the computation efficiency. The proposed method is used to determine in a proactive manner the number of simulations to be done to extract the travel-time estimation for each specific request while respecting an error threshold as output quality level. The methodology requires a reduced effort on the application development side. We adopted an aspect-oriented programming language (LARA) together with a flexible dynamic autotuning library (mARGOt) respectively to instrument the code and to take tuning decisions on the number of samples improving the execution efficiency. Experimental results demonstrate that the proposed adaptive approach saves a large fraction of simulations (between 36% and 81%) with respect to a static approach while considering different traffic situations, paths and error requirements. Given the negligible runtime overhead of the proposed approach, it results in an execution-time speedup between 1.5x and 5.1x. This speedup is reflected at infrastructure-level in terms of a reduction of around 36% of the computing resources needed to support the whole navigation pipeline

Bacterial enzymatic activity and bioavailability of heavy metals in sediments from Boa Viagem Beach (Guanabara Bay)

This study focuses on the quality of the organic matter that reaches the sediment from Boa Viagem Beach and through the evaluation of the total bacterial count, the electron transport system activity (ETSA), the esterase activity (EST), as well as the protein and the organic matter contents. Seasonal variations of organic matter, protein content and the number of bacteria were particularly notable in the summer. ETSA reached a maximum of 7.48 µl O2 h-1 g-1 in the summer. EST activity presented a different pattern once it reached a maximum of 0.17 µg fluorescein h-1 g-1 in the winter. The temporal variation of ETSA and EST activity indicated that biopolymers predominated in the winter, and oligomers or monomers predominated in the summer. These results suggest that organic carbon turnover is more likely to be controlled by organic matter quality. The heavy metals concentrations, especially for Cu, Zn, Ni and Cr, indicated absence of the inhibition of dehydrogenase activity, and they are not bioavailable in the EC50 valuesO trabalho enfoca a qualidade da matéria orgânica do sedimento da Praia da Boa Viagem, avaliando-se a contagem de bactérias, a atividade do sistema transportador de elétrons (ETSA), a atividade de esterases (EST) e a concentração de proteína e matéria orgânica. Variação sazonal de matéria orgânica, de proteína e número de bactérias foi significativo no verão. ETSA apresentou maior valor no verão, 7.48 µl O2 h-1 g-1. A EST foi maior no inverno, chegando a 0.17 µg fluorescein h-1 g-1. A variação temporal de ETSA e EST indicaram que biopolímeros predominaram no inverno e oligômeros e monômeros, no verão. Estes resultados sugerem que a transformação do carbono orgânico é controlado pela qualidade da matéria orgânica. As concentrações dos metais, especialmente Cu, Zn, Ni and Cr, indicam ausência de inibição da atividade das desidrogenase pois não estão biodisponíveis na concentração EC50

Costoclavicular Brachial Plexus Block in Paediatric Anaesthesia: A Retrospective Pilot Study

info:eu-repo/semantics/publishedVersio

Ichthyofauna assemblages from two unexplored Atlantic seamounts: Northwest Bank and João Valente Bank (Cape Verde archipelago)

Underwater censuses by divers were used to study the fish assemblages from two unexplored Atlantic seamounts in the Cape Verde archipelago. Fifty three species of 27 families were recorded: 27 in Northwest Bank and 46 in João Valente Bank. Northwest Bank had dense schools, while João Valente Bank had higher species richness and smaller schools. Both seamounts were dominated mainly by coastal species directly depending on seabed habitat (Demersal or benthopelagic). Of the 53 fish species recorded, 22.6% were of continental African origin, while 9.4% and 5.7% were endemic of the Cape Verde Islands and of the Macaronesia province, respectively. Most species (64.2%) had a very wide biogeographic distribution: cosmopolitan (22.6%), amphi-Atlantic (28.3%) and Atlantic-Mediterranean (13.2%). Northwest Bank and João Valente Bank may have a permanent fish community supported by various oceanographic-topographic interactions. João Valente Bank seems more diverse, which is probably associated with algae cover and with a larger area providing additional suitable and more varied habitats. The geographic proximity to the coast and the presence of oceanic and/or oceanodromous species suggests that the upper part of these seamounts may act both as attraction points and as “stepping-stones” for the dispersal of coastal species.info:eu-repo/semantics/publishedVersio

Analise semiotica de um ava (ambiente virtual de ensino aprendizagem) : características cts através da escada semotica de Stamper

Este artigo demonstra um estudo e aplicação da análise semiótica, para a avaliação de interfaces de ambientes virtuais de ensino-aprendizagem (AVA), de acordo com a escada semiótica de Stamper. Com base nas características CTS (Ciência,Tecnologia e Sociedade) encontrada nas camadas “degrais” da escada. Em específico, usamos a metodologia para qualidade de interfaces definida por Schimiguel, que instancia critérios de qualidade para cada uma das camadas da escada semiótica de Stamper. Com base nos resultados dessa investigação foi possível sugerir algumas recomendações nas seis camadas analisadas, sinalizando ainda para cada uma dessas recomendações um enfoque CTS, uma descrição que tem como propósito facilitar a implementação e otimização de AVAS

Artropodofauna de solo com potencial de uso em programas de controle biológico de pragas em cultivos alternativos de palma de óleo (Elaeis Guineensis).

Avaliou-se a diversidade de artrópodes benéficos (ênfase em insetos) associada à palma de óleo (Elaeis guineensis) cultivada em monocultivo e em sistemas agroflorestais (biodiversificados), com diferentes combinações de preparo de área sem o uso do fogo, no município de Tomé-Açu, Pará. Nos sistemas estudados foram realizadas coletas mensais entre maio de 2009 e janeiro de 2010, utilizando-se armadilhas tipo pitfall, para a captura de artrópodes de solo. As armadilhas permaneceram no campo por 72 horas e após esse período, o material biológico coletado foi processado e transportado para o Laboratório de Entomologia da Embrapa Amazônia Oriental, em Belém, Pará, onde foi triado, quantificado e identificado ao menor nível taxonômico possível. Plantios de palma de óleo biodiversificados com um ano de idade não apresentaram diferenças significativas de ocorrência para os principais grupos de inimigos naturais de solo (Araneae, Coleoptera e Hymenoptera) quando comparados com o plantio convencional solteiro. Entretanto, sistemas biodiversificados apresentaram maiores populações e diversidade de predadores e parasitóides com o potencial de controle biológico de insetos-praga em plantios de palma de óleo. Independente do sistema de cultivo adotado, nossos resultados demonstram que não é possível identificar diferenças nas populações de artrópodes de solo associadas a plantas de palma de óleo no primeiro ano de cultivo.Editores técnicos: Roberto Porro, Milton Kanashiro, Maria do Socorro Gonçalves Ferreira, Leila Sobral Sampaio e Gladys Ferreira de Sousa

Influência da secagem e do tempo de extração no rendimento de óleo essencial de Croton blanchetianus Baill.

O objetivo do trabalho foi avaliar a influência da secagem e do tempo de extração das raspas do caule de marmeleiro, a fim de otimizar o rendimento do óleo essencial