As variedades de arroz vermelho brasileiras.

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3D histopathology of stenotic aortic valve cusps using ex vivo microfocus computed tomography

BackgroundCalcific aortic stenosis (AS) is the most prevalent heart valve disease in developed countries. The aortic valve cusps progressively thicken and the valve does not open fully due to the presence of calcifications. In vivo imaging, usually used for diagnosis, does not allow the visualization of the microstructural changes associated with AS.MethodsEx vivo high-resolution microfocus computed tomography (microCT) was used to quantitatively describe the microstructure of calcified aortic valve cusps in full 3D. As case study in our work, this quantitative analysis was applied to normal-flow low-gradient severe AS (NF-LG-SAS), for which the medical prognostic is still highly debated in the current literature, and high-gradient severe AS (HG-SAS).ResultsThe volume proportion of calcification, the size and number of calcified particles and their density composition was quantified. A new size-based classification considering small-sized particles that are not detected with in vivo imaging was defined for macro-, meso- and microscale calcifications. Volume and thickness of aortic valve cusps, including the complete thickness distribution, were also determined. Moreover, changes in the cusp soft tissues were also visualized with microCT and confirmed by scanning electron microscopy images of the same sample. NF-LG-SAS cusps contained lower relative amount of calcifications than HG-SAS. Moreover, the number and size of calcified objects and the volume and thickness of the cusps were also lower in NF-LG-SAS cusps than in HG-SAS.ConclusionsThe application of high-resolution ex vivo microCT to stenotic aortic valve cusps provided a quantitative description of the general structure of the cusps and of the calcifications present in the cusp soft tissues. This detailed description could help in the future to better understand the mechanisms of AS

Modelling carbon mitigation pathways by 2050: insights from the global calculator

The Global Calculator (GC) can be used to assess a wide range of climate change mitigation pathways. The GC is an accessible integrated model which calculates the cumulative emissions of a basket of the main greenhouse gases that result from a set of technological and lifestyle choices made at the global level and as defined by the user within a single system dynamics tool. Using the GC, we simulated ambitious scenarios against business as usual trends in order to stay below 2oC and 1.5oC of maximum temperature change by the end of this century and carried out a sensitivity analysis of the entire GC model option space. We show that the calculator is useful for making broad simulations for energy, carbon and land use dynamics, and demonstrate how combined and sustained mitigation efforts across different sectors are urgently needed to meet climate targets

Unstructured, curved elements for the two-dimensional high order discontinuous control-volume/finite-element method

Quadrilateral and triangular elements with curved edges are developed in the framework of spectral, discontinuous, hybrid control-volume/finite-element method for elliptic problems. In order to accommodate hybrid meshes, encompassing both triangular and quadrilateral elements, one single mapping is used. The scheme is applied to two-dimensional problems with discontinuous, anisotropic diffusion coefficients, and the exponential convergence of the method is verified in the presence of curved geometries

Can we import quality tools? a feasibility study of European practice assessment in a country with less organised general practice

<p>Abstract</p> <p>Background</p> <p>Quality is on the agenda of European general practice (GP). European researchers have, in collaboration, developed tools to assess quality of GPs. In this feasibility study, we tested the European Practice Assessment (EPA) in a one-off project in Belgium, where general practice has a low level of GP organisation.</p> <p>Methods</p> <p>A framework for feasibility analysis included describing the recruiting of participants, a brief telephone study survey among non-responders, organisational and logistic problems. Using field notes and focus groups, we studied the participants' opinions.</p> <p>Results</p> <p>In this study, only 36 of 1000 invited practices agreed to participate. Co-ordination, administrative work, practice visits and organisational problems required several days per practice. The researchers further encountered technical problems, for instance when entering the data and uploading to the web-based server. In subsequent qualitative analysis using two focus groups, most participant GPs expressed a positive feeling after the EPA procedure. In the short period of follow-up, only a few GPs reported improvements after the visit. The participant GPs suggested that follow-up and coaching would probably facilitate the implementation of changes.</p> <p>Conclusion</p> <p>This feasibility study shows that prior interest in EPA is low in the GP community. We encountered a number of logistic and organisational problems. It proved attractive to participants, but it can be augmented by coaching of participants in more than a one-off project to identify and achieve targets for quality improvement. In the absence of commitment of the government, a network of universities and one scientific organisation will offer EPA as a service to training practices.</p

Parameterization of subgrid-scale processes in finite element sea ice - ocean models

With the continuous improvement of models for better climate studies and predictions, simulating small scale physical processes remain a challenge. From this perspective, subgrid-scale parameterizations are used whenever such processes cannot be explicitly represented and when their inclusion is beneficial to simulations. However, the parameterizations result from approximations of the reality and also present drawbacks in specific circumstances. In order to prevent these parameterizations from shifting to unphysical behaviours, numerical artefacts are frequently used. In models based on the finite element method, these artefacts are distinctive due to the specificity of the formalism itself. The goal of this doctoral thesis is first to find the best compromise between these numerical artefacts and the preservation of physical processes, through the study of subgrid-scale oceanic parameterizations in a model based on the finite element method. Second, a coupled sea ice – ocean model is built from two disctinct models in order to take advantages of each of them, i.e., unstructured meshes and sophisticated representation of sea ice physics. Through this thesis, these different models are successively used in configurations of increasing complexity, in order to understand the impacts of parameterizations on the models physics accuracy and their skills with respect to observations.(SC - Sciences) -- UCL, 201