786 research outputs found
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
Underwater survey of ichthyofauna of eastern Atlantic seamounts: Gettysburg and Ormond (Gorringe Bank)
Gettysburg and Ormond are seamounts belonging to the Gorringe Bank, which is located on the
Europen-African plate boundary. Given the importance of these oceanic features for understanding
marine biodiversity patterns, two surveys were carried out in 1998 (Gettysburg) and 1999 (Ormond)
using diving, photography and video for species identification and abundance evaluation. Of the 9 fish
species found at Gettysburg and 11 at Ormond, 6 were common to both sites and these included the
dominant species: the oceanic and commercially important, Seriola rivoliana, and the coastal, typically
Atlantic-Mediterranean Coris julis and Anthias anthias. The strong representation of coastal, demersal
and Atlantic-Mediterranean species in the Gorringe Bank region and the presence of Abudefduf luridus,
an endemic Macaronesian species, at Gettysburg suggests that the upper part of these seamounts may
have acted and still act as “stepping stones” for the dispersal of coastal species.info:eu-repo/semantics/publishedVersio
Targeted killing of ocular Streptococcus pneumoniae by the phage endolysin MSlys
This study describes the translational potential of the pneumococcal endolysin MSlys as a novel approach to uniquely target and kill Streptococcus pneumoniae causing ocular infections.This study was partially supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit. MDS was supported from a FCT doctoral fellowship, reference SFRH/BD/128825/2017. CA was supported by a scholarship from Fondation pour la Recherche Médicale (FDM202006011203). This work was also supported in part by the New England Corneal Transplant Research Fund (PJMB). Funding agencies had no role in study design, data analysis, decision to publish or preparation of the manuscript.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
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