La Netiquette

Construyendo una reputación on line: un elemento estratégico de interacción entre las empresas con sus usuarios, comentaristas e infaltables trolls

Wildlife Conservation, perceptions of different co-existing cultures

Different cultures have different relationships with nature, and these relationships have many dimensions which shape people’s perceptions towards nature. Therefore, perceptions may vary between different cultures within the same territories. Understanding each culture´s relationship with the surrounding environment is of extreme importance for the correct allocation of conservation resources, and for the development of efficient conservation actions. In this study, we discuss the perceptions of two different cultures regarding large and mediumsized mammal conservation in an endangered region of Argentina, called the Dry Chaco. These two cultures are peasants, or Criollos, and the indigenous Wichís; we assessed and compared their perceptions on local extinctions, conservation problems, conflicts with wildlife and possible solutions for these issues. We found that although both cultures inhabit the same territory and report local extinctions, their perceptions on which species were locally extinct differed. Another difference was the perceived time-period in which disappearances occurred. We also found that most respondents recognize conservation problems and possible solutions, although these differ between both cultures. Management for conservation of these species should be specific to each culture, and understanding local perspectives allows the inclusion of a broader view of human needs, perceptions and knowledge in conservation programs.Fil: Camino, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo. Grupo de Ecología del Paisaje y Medio Ambiente; ArgentinaFil: Cortez, Sara. No especifica;Fil: Cerezo, Alexis. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; ArgentinaFil: Altrichter Mariana. Prescott University; Estados Unido

Determinantes del rendimiento académico de los alumnos en escuelas públicas y privadas en México

El trabajo muestra los resultados del estudio de los determinantes del rendimiento académico en estudiantes que ya terminaron o están por terminar la educación básica obligatoria en escuelas públicas y privadas en México, empleando los datos PISA 2012, en el cual las estimaciones sugieren que existe un impacto positivo de ciertos factores como el índice socioeconómico, la educación de la madre y, en una menor medida, la educación del padre, esto en el rendimiento escolar de los alumnos, de igual manera, que la madre del alumno viva con él tiene un impacto fuerte en el rendimiento escolar. Un resultado importante desde el punto de vista de política pública es que la educación preescolar tiene un impacto positivo en el rendimiento académico de ambos tipos de escuela y, además, reduce la brecha entre ambos tipos de escuela. También, las estimaciones muestran evidencia de que existe un sesgo de selección para ambos tipos de escuela, es decir, los alumnos no eligen ir a una escuela pública o privada, más bien son las características del alumno las que intervienen en la inclusión de éstos en el tipo de escuela

Procedures for finite element mesh generation from medical imaging: application to the intervertebral disc

Dissertação de mestrado integrado em Engenharia BiomédicaThe paramount goal of this ‘half-year’ work is the development of a set of methodologies and procedures for the geometric modelling by a finite element (FE) mesh of the bio-structure of a motion segment (or functional spinal unit), i.e., two vertebrae and an intervertebral disc, from segmented medical images (processed from medical imaging). At an initial stage, a three-dimensional voxel-based geometric model of a goat motion segment was created from magnetic resonance imaging (MRI) data. An imaging processing software (ScanIP/Simplewire) was used for imaging segmentation (identification of different structures and tissues), both in images with lower (normal MRI) and higher (micro-MRI) resolutions. It shall be noticed that some soft-tissues, such as annulus fibrosus or nucleus pulposus, are very hard to isolate and identify given that the interface between them is not clearly defined. At the end of this stage, images with different resolutions allowed to generate different 3D voxel-based geometric models. Thereafter, a procedure for the FE mesh generation from the aforementioned voxelized data should be studied and applied. However, as the original geometry was only approximately known from real medical imaging, it was difficult to objectively quantify the quality of the FE meshing procedure and the accuracy between source geometry and target FE mesh. In order to overcome such difficulties, and due to the lack of quality of the available medical imaging, a “virtualization” procedure was developed to create a set of segmented 2D medical images from a well-defined geometry of a motion segment. The main idea was to create the conditions to quantify the quality and the accuracy of the developed FE meshing procedure, as well to study the effect of imaging resolution. Starting from the virtually generated 2D segmented images, a 3D voxel-based structure was achieved. Given that initial domains are now clearly defined, there is no need for further image processing. Then, a two-step FE mesh generation procedure (generation followed by simplification) allows to create an optimized tetrahedral FE mesh directly from 3D voxelized data. Finally, because the virtualization procedure allowed to know the initial geometry, one is able to objectively quantify the quality and the accuracy of the final simplified tetrahedral FE mesh, and thus to understand and quantify: a) the role of the medical image resolution on the FE geometrical reconstruction, b) the procedure and parameters of the FE mesh generation step, and c) the procedure and parameters of the FE mesh simplification step, and thus to give a clear contribution in the definition of the procedure for the FE mesh generation from medical imaging in case of an intervertebral disc.O objetivo fundamental deste trabalho de seis meses é o desenvolvimento de um conjunto de metodologias e procedimentos para a modelação geométrica, através de uma malha de elementos finitos (EF) de uma bio-estrutura de um motion segment (ou unidade funcional da coluna), ou seja, duas vértebras e um disco intervertebral, a partir de imagens médicas segmentadas (processadas a partir de imagiologia médica). Numa fase inicial, um modelo geométrico tridimensional baseado em voxels de um motion segment de uma cabra foi criado a partir de informação de imagens médicas de ressonância magnética (RM). Um software de processamento de imagem (ScanIp/Simplewire) foi usado para segmentação de imagens (identificação de diferentes estruturas e tecidos), em imagens de menor (RM normal) e maior (micro-RM) resolução. Deve ser referido que alguns tecidos moles, como o anel fibroso e o núcleo pulposo são muito difíceis de isolar e identificar, dado que as fronteiras destes não estão claramente definidas. No final desta etapa, as imagens com diferentes resoluções permitiram gerar diferentes modelos geométricos 3D baseados em voxels. Posteriormente, um procedimento para geração de malha de EF, a partir da informação voxelizada acima mencionada, deveria ser estudado e aplicado. No entanto, como a geometria original era aproximadamente conhecida a partir de imagens médicas reais, foi difícil quantificar objetivamente a qualidade do procedimento de geração de malha de EF e a precisão entre a geometria de origem e a malha de EF de destino. A fim de superar tais dificuldades, e devido à falta de qualidade de imagens médicas disponíveis, um procedimento de “virtualização” foi desenvolvido para criar um conjunto de imagens médicas 2D segmentadas a partir de uma geometria de um motion segment bem conhecida. A principal ideia foi criar as condições para quantificar a qualidade e a precisão do procedimento de geração de malha de EF desenvolvido, bem como estudar o efeito da resolução da imagem médica. A partir das imagens 2D segmentadas, geradas virtualmente, uma estrutura de voxels 3D pode ser conseguida. Dado que os domínios iniciais estão agora claramente definidos, não há necessidade de processamento de imagem adicional. Por conseguinte, um procedimento de geração de malha de EF de duas etapas (geração seguida por simplificação) permite criar uma malha de EF tetraédrica otimizada diretamente a partir de informação 3D voxelizada. Por fim, como o procedimento de virtualização permitiu conhecer a geometria inicial, é possível quantificar objetivamente a qualidade e exatidão da malha de EF tetraédrica final simplificada, e assim, compreender e quantificar: a) o papel da resolução da imagem médica na reconstrução geométrica de EF; b) o procedimento e os parâmetros da etapa de geração de malha de EF; c) o procedimento e os parâmetros da etapa de simplificação de malhas de EF, e assim, dar uma contribuição clara na definição do procedimento para a geração de malha de EF a partir de imagem médica, no caso de um disco intervertebral.European Project : NP Mimetic - Biomimetic Nano-Fiber Based Nucleus Pulposus Regeneration for the Treatment of Degenerative Disc Disease, funded by the European Commission under FP7 (grant NMP3-SL-2010-246351

Optimized FE mesh generation based on medical imaging and on a user-defined spatial refinement gradient. Application to a motion segment

In general, the starting point for the 3D geometrical modelling by finite elements of an anatomical structure is the generation of a 3D voxel-based geometrical model, obtained after denoising, smoothing and segmentation of a set of 2D medical images. The accuracy of the FE computation increases if the geometry of model resembles, for instance, the natural smoothness of real anatomical structure. Usually, the lack of detailed data in conventional imaging techniques causes further problems in the IVD finite element mesh generation and analysis. Difficulties arise mainly due to the complexity and the dimension of the IVD constituent structures and the lower resolution of medical imaging. After the 3D voxelized model has been defined, a specific isotropic tetrahedral FE meshing procedure is applied and, generally, a too dense and highly refined FE mesh is obtained. Therefore, it is necessary to decrease its size by diminishing the total number of nodes and elements while maintaining both geometrical accuracy and a physically compatible FE mesh refinement. Generally, after this procedure, the smaller elements are located at the internal and external boundaries, while larger elements are located inside the FE mesh. However, this is not always acceptable. There may be situations where this accuracy may be required simultaneously in structures outside and inside the FE mesh. In a motion segment, the FE mesh should be more refined at the IVD and coarser at the vertebrae (nearly incompressible medium). On the other hand, since the annulus fibrosus (AF) is a stiff ring-shaped structure made up of concentric lamellae [1], an optimized FE mesh should be more refined at the annulus fibrosus than at the nucleus pulposus (NP)The aims of this study are: - to study the impact of medical imaging resolution in the FE mesh accuracy; - to develop a refinement gradient, where in this case the elements should be smaller in the outer annulus (where lamellae are denser and combined) than the ones in the inner annulus (less dense lamellae)

3D reconstruction of a spinal motion segment from 2D medical images: objective quantification of the geometric accuracy of the FE mesh generation procedure

The Finite Element (FE) Analysis is an essential tool to study the biomechanical behaviour of the spine, and particularly of the intervertebral disc (IVD). The 3D reconstruction of a patient-oriented IVD has numerous obstacles. Difficulties arise mainly due to the complexity and dimensions of the IVD’s constituent structures. The lack of detailed data in conventional imaging techniques causes further problems in the IVD finite element mesh generation and analysis. The accuracy of the FE computation increases if the geometry of model resembles, for instance, the natural smoothness of real anatomical structure. Accounting to this, the main idea of this work is to evaluate the impact of the reconstruction parameters by comparing the final 3D geometrical reconstruction by finite elements with an initial well-defined geometry of a given anatomical structure, and to develop the procedures for the 3D mesh generation from 2D medical imaging

O desempenho da administração fiscal e o papel das direcções de finanças na actividade de auditoria.

Relatório de estágio no âmbito do mestrado em Gestão apresentada à Fac. de Economia da Universidade de Coimbra

A FERROVIA E O VALE DO CARIRI: USOS E DISCURSOS SOBRE A CONSTRUÇÃO DA ESTRADA DE FERRO NO SUL DO CEARÁ

Since the late nineteenth century, the Cariri region in the south of the state of Ceará was identified as an outstandingly fertile space with lavish nature and landscapes easily associated with the idea of an earthly paradise. Its green aspect in the presence of the Chapada do Araripe was often exalted in speeches, local newspapers and speeches made by intellectuals and politicians linked to Ceara as well as the Cariri region, more specifically. However, far from being restricted to this fact, the idea of a Cariri with evergreen landscapes and extraordinarily fertile land was also forged in the context of social relations and disputes, such as trying to attract to this space the rails of the Baturité Railway. In this sense, the discourses that presented the Cariri region like an oasis in the midst of a dryland has a historical perspective, which permeated the green landscapes of the foothills of the Araripe, but also permeated disputes over the railwayDesde o final do século XIX, a região do Cariri cearense, no sul do Estado, foi apontada como espaço destacadamente fértil, com natureza pródiga e paisagens facilmente associadas a ideia de um paraíso terrestre. Seu aspecto verdejante propiciado na presença da Chapada do Araripe foi frequentemente exaltado em discursos, jornais locais e falas de intelectuais e políticos ligados ao Ceará, e ao Cariri, mais especificamente. Contudo, longe de estar restrita a esse fato, a ideia de um Cariri com paisagens sempre verdes e terrenos extraordinariamente férteis também foi forjado no âmbito de relações e disputas sociais, como a tentativa de atrair para esse espaço os trilhos da Estrada de Ferro de Baturité. Nesse sentido, os discursos que narraram o Cariri como oásis em meio a uma terra seca tem construção histórica, que perpassaram as paisagens verdes do sopé da Chapada do Araripe, mas também perpassaram as disputas pela ferrovia

Do MAFLD patients with harmful alcohol consumption have a different dietary intake?

© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).The term metabolic-associated fatty liver disease (MAFLD) has been proposed to define positively fatty liver disease in the form associated with metabolic risk factors. The aim of this study was to assess the dietary intake of MAFLD and explore a possible relationship between its inflammatory characteristics (assessed by Dietary Inflammatory Index-DII®), the degree of liver fibrosis (assessed by transient elastography), and the amount of alcohol intake. MAFLD patients were included (n = 161) and were classified, according to the amount of alcoholic intake, as MAFLD without alcohol intake (n = 77) and MAFLD with alcohol intake (n = 84), with 19 presenting harmful alcoholic consumption. Dietary intake was 1868 ± 415 kcal/day and did not present differences in energy or nutrient intake based on the presence of metabolic comorbidities. Patients with MAFLD and alcohol intake consumed significantly more energy and presented a tendency for higher intake of carbohydrates and sugar. Patients with harmful alcohol intake presented a higher intake of total fat and cholesterol compared with moderate alcohol intake. There were no differences in DII® based on fibrosis severity or the amount of alcohol consumption. This work contributes to the characterization of baseline dietary intake in MAFLD patients, paving the way to design more suited dietary interventional trials.info:eu-repo/semantics/publishedVersio

Optimized FE mesh generation procedure based on a user-defined spatial refinement gradient. Application to a motion segment

Finite Element (FE) meshes are usually highly refined and dense and, consequently, computationally very expensive. Therefore, after the preliminary FE mesh generation, it is necessary to decrease its size by diminishing the total number of nodes and elements while maintaining both geometrical accuracy and a physically-meaningful FE mesh refinement. The aim of this work is to describe an optimized FE mesh simplification procedure based on edge contraction and on a user-defined spatial refinement gradient criterion. The main idea is that, for normal mechanical loadings applied to a motion segment, the vertebrae shall behave almost as an incompressible medium, and only the intervertebral disc (IVD) should undergo relevant strains. In this case, it is acceptable (and desirable) to attain a problem-functional FE mesh, in which the FE mesh should be more refined at the IVD and coarser at vertebrae. On the other hand, an optimized FE mesh should be more refined at the annulus fibrosus than at the nucleus pulposus. In summary, the proposed FE mesh generation and simplification procedure, being based on a user-definable spatial FE mesh refinement gradient, allows the user to define precisely the required refinement and thus to reduce drastically the number of elements in the final FE mesh and consequently to diminish the computation time required for the FE analysis, while keeping the necessary physical meaning on the FE mesh. The aforesaid procedure will be applied to the FE mesh generation (based on [1]) of a motion segment initially characterized by medical imaging