4,247 research outputs found
Random attractors for stochastic 2D-Navier-Stokes equations in some unbounded domains
We show that the stochastic flow generated by the Stochastic Navier-Stokes
equations in a 2-dimensional Poincar\'e domain has a unique random attractor.
This result complements a recent result by Brze\'zniak and Li [10] who showed
that the flow is asymptotically compact and generalizes a recent result by
Caraballo et al. [12] who proved existence of a unique pullback attractor for
the time-dependent deterministic Navier-Stokes equations in a 2-dimensional
Poincar\'e domain
Smart and networking underwater robots in cooperation meshes : the swarms ECSEL : H2020 project
The work presented on this paper is aimed to explain the role that
unmanned underwater vehicles (AUVs/ROVs) plays in the ECSEL-H2020 SWARMS
project. The main goal of the project is to reduce the operational cost and increase
the safety of tasks assigned to divers in these operations. This will be achieved
enabling the AUVs/ROVs to work in a cooperative mesh. The challenge is to design
and develop an integrated platform (a set of Software/Hardware components),
incorporated into the current generation of underwater vehicles in order to
improve autonomy, cooperation, robustness, cost-effectiveness, and reliability of
the offshore operations. The first demonstration of the project will be performed at
PLOCAN (Oceanic Platform of the Canary Islands) where these technologies will be
validated on its first stage.Peer Reviewe
Postgraduate Medical Teaching
Os autores afirmam a urgência em reestruturar o ensino medico pós-graduado em Portugal.
De uma forma critica, analisam esquematicamente a situação actual do ensino médico pós-graduado em geral e da Urologia em particular, no nosso país.
Depois de enunciar as etapas para atingir o internato da especialidade, resumem o Plano de preparação para a especialidade de Urologia do Conselho Directivo do Colégio de Urologistas da Ordem dos Médicos, de 1979. 0 Plano refere-se a tempos de estágio, programas teórico e prático, e formas de avaliação dos internos e aponta ainda as características para que um serviço seja considerado idóneo. Referindo que a realidade actual não corresponde às exigências preconizadas, os autores indicam aquilo que de facto acontece.
Respondendo negativamente a uma série de questões sobre pontos fulcrais para uma prática correcta do ensino pós-graduado, os autores terminam a primeira parte da sua exposição perguntando se, nas condições actuais, o resultado final da preparação dos médicos será mesmo um Especialista.
Na segunda parte fazem propostas para a reestruturação do ensino pós-graduado em Portugal. Referem-se sucessivamente as seguintes alíneas: criação de institutos ou escolas médicas hospitalares de pós
graduação, universitários; elaboração de um programa padrão nacional do ensino médico pós-graduado; criação de comissões para o ensino médico pós-graduado; definição exigente do perfil de serviço idóneo
para o ensino médico pós-graduado; elaboração de programas individuais pelos serviços dos institutos de pós-graduação; caderneta; fiscalização da actividade dos docentes e discentes; avaliação, contínua e por
provas intercalar e final; mestrado.
Dado o carácter auto-explicativo dos quadros, os autores, para além de alguns comentários, apenas desenvolvem as alíneas referentes aos Institutos ou Escolas Médicas de Pós-graduação, Universitários e
ao Mestrado, expondo, duma maneira sucinta, a forma como pensam que deviam ser organizados
Transferability of environmental favourability models in geographic space: The case of the Iberian desman (Galemys pyrenaicus) in Portugal and Spain
Transferring distribution models between different geographical areas may be problematic, as the performance
of models outside their original scope is hard to predict. A modelling procedure is needed that
gets the gist of the environmental descriptors of a distribution area, without either overfitting to the
training data or overestimating the species’ distribution potential.We tested the transferability power of
the favourability function, a generalized linear model, on the distribution of the Iberian desman (Galemys
pyrenaicus) in the Iberian territories of Portugal and Spain.We also tested the effects of two of the main
potential constraints on model transferability: the analysed ranges of the predictor variables, and the
completeness of the species distribution data. We modelled 10 km×10km presence/absence data from
Portugal and Spain separately, extrapolated each model to the other country, and compared predictions
with observations. The Spanish model, despite arguably containing more false absences, showed good
predictive ability in Portugal. The Portuguese model, whose predictors ranged between only a subset of
the values observed in Spain, overestimated desman distribution when transferred.We discuss possible
reasons for this differential model behaviour, and highlight the importance of this kind of models for
prediction and conservation application
Otter (Lutra lutra) distribution modeling at two resolution scales suited to conservation planning in the Iberian Peninsula
We used the results of the Spanish Otter Survey of 1994–1996, a Geographic Information System and stepwise multiple logistic
regression to model otter presence/absence data in the continental Spanish UTM 10 10-km squares. Geographic situation, indicators
of human activity such as highways and major urban centers, and environmental variables related with productivity, water
availability, altitude, and environmental energy were included in a logistic model that correctly classified about 73% of otter presences
and absences. We extrapolated the model to the adjacent territory of Portugal, and increased the model’s spatial resolution
by extrapolating it to 1 1-km squares in the whole Iberian Peninsula. The model turned out to be rather flexible, predicting, for
instance, the species to be very restricted to the courses of rivers in some areas, and more widespread in others. This allowed us to
determine areas where otter populations may be more vulnerable to habitat changes or harmful human interventions.
# 2003 Elsevier Ltd. All rights reserved
Trigger and readout electronics for the STEREO experiment
The STEREO experiment will search for a sterile neutrino by measuring the
anti-neutrino energy spectrum as a function of the distance from the source,
the ILL nuclear reactor. A dedicated electronic system, hosted in a single
microTCA crate, was designed for this experiment. It performs triggering in two
stages with various selectable conditions, processing and readout via UDP/IPBUS
of 68 photomultiplier signals continuously digitized at 250 MSPS. Additionally,
for detector performance monitoring, the electronics allow on-line calibration
by driving LED synchronously with the data acquisition. This paper describes
the electronics requirements, architecture and the performances achieved.Comment: Topical Workshop on Electronics for Particle Physics (TWEPP) 2015,
Lisboa. 9 pages, 9 figure
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