A Deficiency Problem of the Least Squares Finite Element Method for Solving Radiative Transfer in Strongly Inhomogeneous Media

The accuracy and stability of the least squares finite element method (LSFEM) and the Galerkin finite element method (GFEM) for solving radiative transfer in homogeneous and inhomogeneous media are studied theoretically via a frequency domain technique. The theoretical result confirms the traditional understanding of the superior stability of the LSFEM as compared to the GFEM. However, it is demonstrated numerically and proved theoretically that the LSFEM will suffer a deficiency problem for solving radiative transfer in media with strong inhomogeneity. This deficiency problem of the LSFEM will cause a severe accuracy degradation, which compromises too much of the performance of the LSFEM and makes it not a good choice to solve radiative transfer in strongly inhomogeneous media. It is also theoretically proved that the LSFEM is equivalent to a second order form of radiative transfer equation discretized by the central difference scheme

A concise review on THGEM detectors

We briefly review the concept and properties of the Thick GEM (THGEM); it is a robust, high-gain gaseous electron multiplier, manufactured economically by standard printed-circuit drilling and etching technology. Its operation and structure resemble that of GEMs but with 5 to 20-fold expanded dimensions. The millimeter-scale hole-size results in good electron transport and in large avalanche-multiplication factors, e.g. reaching 10^7 in double-THGEM cascaded single-photoelectron detectors. The multiplier's material, parameters and shape can be application-tailored; it can operate practically in any counting gas, including noble gases, over a pressure range spanning from 1 mbar to several bars; its operation at cryogenic (LAr) conditions was recently demonstrated. The high gain, sub-millimeter spatial resolution, high counting-rate capability, good timing properties and the possibility of industrial production capability of large-area robust detectors, pave ways towards a broad spectrum of potential applications; some are discussed here in brief.Comment: 8 pages, 11 figures; Invited Review at INSTR08, Novosibirsk, Feb 28-March 5 200

Local volume fraction distributions of axons, astrocytes, and myelin in deep subcortical white matter

This study aims to statistically describe histologically stained white matter brain sections to subsequently inform and validate diffusion MRI techniques. For the first time, we characterise volume fraction distributions of three of the main structures in deep subcortical white matter (axons, astrocytes, and myelinated axons) in a representative cohort of an ageing population for which well-characterized neuropathology data is available. We analysed a set of samples from 90 subjects of the Cognitive Function and Ageing Study (CFAS), stratified into three groups of 30 subjects each, in relation to the presence of age-associated deep subcortical lesions. This provides volume fraction distributions in different scenarios relevant to brain diffusion MRI in dementia. We also assess statistically significant differences found between these groups. In agreement with previous literature, our results indicate that white matter lesions are related with a decrease in the myelinated axons fraction and an increase in astrocytic fraction, while no statistically significant changes occur in axonal mean fraction. In addition, we introduced a framework to quantify volume fraction distributions from 2D immunohistochemistry images, which is validated against in silico simulations. Since a trade-off between precision and resolution emerged, we also performed an assessment of the optimal scale for computing such distributions

VINHOS QUE PENSAM - parte I/III GESTÃO DO VIGOR VEGETATIVO DA VINHA A PARTIR DE SENSORES ATIVOS MUTIESPECTRAIS PRÓXIMOS

Costumo dizer que o projeto “Vinhos que pensam” nasceu de um aperto de mão entre a equipa de Agricultura de Precisão da Universidade de Évora e a Fundação Eugénio de Almeida, nasceu sem financiamento próprio mas com uma visão muito clara de criar valor social na área da vitivinicultura Alentejana. Passados 6 anos, julgamos que o conhecimento produzido é relevante para a atividade e gestão vitivinícola Alentejana, no entanto, novas perguntas surgem todos os anos e dessa forma somos alimentados na motivação de prosseguir com este projeto, ao qual, outras entidades e vontades se vão agora também associando. A Agrobótica, muito recentemente, desafiou-nos a apresentar os resultados mais relevantes do projeto “Vinhos que pensam” e com o maior prazer lhe dissemos que sim, no entanto, colocou-se-nos um problema, os resultados mais relevantes, muito dificilmente caberiam num único artigo, como tal, decidimos dividir tais resultados em três artigos, este primeiro mais virado para os aspetos da gestão do vigor da vegetação da vinha; o segundo mais virado para os sensores geoelétricos do solo e sua aplicação na gestão e estudo do solo; e por fim, um terceiro mais virado para aspetos da nutrição das plantas considerando a interação solo/planta e a utilização dos sensores multiespectrais

VINHOS QUE PENSAM - parte II/III UTILIZAÇÃO DA CONDUTIVIDADE ELÉTRICA APARENTE DO SOLO NA INSTALAÇÃO E GESTÃO DAS CULTURAS: EXEMPLIFICAÇÃO NA VINHA

o principal objetivo deste trabalho passou por verificar: • a relação entre a CEa do solo e os indicadores de textura; • se a CEa do solo poderá ser um parâmetro importante na instalação e gestão de parcelas de vinha ou outro tipo de culturas

Brief update on the satellite tagging of Atlantic swordfish

This paper provides a brief update of the study on habitat use for swordfish, developed within the working plan of the Swordfish Species Group of ICCAT. A total of 9 miniPAT tags have been deployed by observers on Portuguese and Spanish vessels and the Uruguayan research cruise in the North and South Atlantic. Data from eight tags/specimens are available, four specimens suffered from post-release mortality and one individual tag pop-up date has not occurred yet. These preliminary results showed swordfish moved in several directions, travelling considerable distances. Swordfish spent most of the daytime in deeper waters, being closer to the surface during night-time. The main plan for the next phase of the project is to continue the tag deployment during 2020 in several regions of the Atlantic Ocean and Mediterranean Sea

BRIEF UPDATE ON THE SATELLITE TAGGING OF ATLANTIC SWORDFISH

This paper provides a brief update of the study on habitat use for swordfish, developed within the working plan of the Swordfish Species Group of ICCAT. A total of 9 miniPAT tags have been deployed by observers on Portuguese and Spanish vessels and the Uruguayan research cruise in the North and South Atlantic. Data from eight tags/specimens are available, four specimens suffered from post-release mortality and one individual tag pop-up date has not occurred yet. These preliminary results showed swordfish moved in several directions, travelling considerable distances. Swordfish spent most of the daytime in deeper waters, being closer to the surface during night-time. The main plan for the next phase of the project is to continue the tag deployment during 2020 in several regions of the Atlantic Ocean and Mediterranean SeaEn prens

Preliminary management strategy evaluation for blue shark in the Indian Ocean using a data-limited approach

In tuna-RFMOs there has been an effort to move to quantitative stock assessments for pelagic sharks, especially for the main species such as blue shark Prionace glauca. In IOTC, blue shark was last assessed in 2017 with the use of an integrated length-based age-structured model (SS3). This paper now presents a preliminary exercise with data-limited Management Strategy Evaluation (MSE) to test options for different potential management procedures (MPs), using the data-limited methods toolkit (DLMtool). Reference points have not yet been adopted for sharks in IOTC, so for this exercise we set some tentative reference points noting that those can be updated in the future as needed. Eighty-nine MPs were evaluated with 9 considered potentially acceptable. Options and tradeoffs between those MPs are shown and described in the paper. We have focused mainly on trade-offs between biomass and yield, but according to the management objectives agreed other performance metrics can be applied. Even thought this is a preliminary exercise at this point, we hope that it provides initial thoughts and opens the discussion for the advancement of the blue shark management and conservation in the Indian Ocean