A Mixed Hybrid Finite Volume Scheme for Incompressible Navier-Stokes

Mixed Virtual Elements (MVE) is an innovative class of discretization schemes allowing solution of PDEs on virtually any mesh; such schemes stem from the idea of building discrete operators mimicking certain key properties of their continuous counterparts. In our previous work [27] we implemented our own 1st-order MVE scheme for convection-diffusion. In the present work, a) we extend such scheme to formally 2nd-order accuracy, b) we deal with the subsequent stability issues, c) we derive a full formally 2nd-order MVE scheme for incompressible steady-state Navier-Stokes, d) we provide a first suggestion for a MVE N-S solution algorithm. Numerical results are reported for benchmark test cases

Alternative Solution Algorithms for Primal and Adjoint Incompressible Navier-Stokes

Regardless of the specific discretisation framework, the discrete incompressible Navier-Stokes equations present themselves in the form of a non-linear, saddle-point Oseentype system. Traditional CFD codes typically solve the system via the well-known SIMPLE-like algorithms, which are essentially block preconditioners based on Schur complement theory. Due to their “segregated” nature, which reduces to iteratively solving a sequence of linear systems smaller than the full Oseen and better conditioned, traditional SIMPLE-like algorithms have long been considered as the only viable strategy. However, recent progress in computational power and linear solver capabilities has led researchers to develop, for Oseen-type systems (and discrete Navier-Stokes in particular), a number of alternative preconditioners and solution schemes, found to be more efficient than SIMPLE-like strategies but previously deemed practically unfeasible in industrial contexts. The improved efficiency of novel preconditioners entails a) faster, more stable convergence and b) the possibility of driving residuals below more strict tolerances, which is sometimes difficult with SIMPLE due to stagnating behaviour. The second aspect in particular is extremely relevant in the context of adjoint-based optimisation, as evidence suggests that an adjoint system may be affected by convergence issues when the primal flow solution is not well converged. In this work, we present some solution schemes (both traditional and novel) implemented for the Mixed Hybrid Finite Volumes Navier-Stokes solver we introduced in our previous work. Performance, in terms of robustness and convergence properties, is assessed on a series of benchmark test cases. We also turn our attention to the discrete adjoint Navier-Stokes problem itself, which in essence requires solving a linear system similar to the original Oseen and therefore may benefit from the same preconditioning techniques. We show how the primal algorithms are adapted to the adjoint system, and we run a series of adjoint test cases to compare performance of various solution scheme

STATE OF THE ART OF PSYCHOMOTOR EDUCATION AT THE PRESCHOOL LEVEL IN THE COMMUNE OF PORTO-NOVO IN BENIN

Context: In general, well-conducted psychomotor activities promote harmonious development and have a positive impact on children's health. These activities also condition the acquisition and improvement of the child's global motor skills. In the Commune of Porto-Novo, incomplete motor skills are observed among primary school children in both the public and private sectors. This is why the present study aims to investigate the causes of this observation in kindergarten in order to propose approaches to remedy it. Materials and Method: Twenty-seven (27) teachers from both public kindergartens with at least 100 pupils (15) and private kindergartens with at least 70 pupils (12) were randomly selected. They were grouped according to spontaneous, hidden and evoked interventions. Spontaneous and hidden interventions represent practices that are not conducive to children's psychomotor development, whereas evoked intervention was found to be the best option for promoting children's psychomotor development. Data were collected through individual semi-directive interviews and open observation in the classrooms. These data were analyzed and the percentages were compared. Results: Only 8 teachers (29.63%) practiced an evoked intervention. However, 19 teachers (70.37%) practiced either spontaneous (11) or covert (8) intervention. The comparison of these observed percentages shows a significant difference (p<0.05) at the 5% risk. Conclusion: The incomplete achievements observed at the primary level are due to the lack of space, and teaching materials and especially to the lack of knowledge of the concept of psychomotricity and its implications. Initial training that deviates from these requirements does not seem to be conducive to the harmonious psychomotor development of kindergarten children.  Article visualizations

Successfully treated necrotizing fasciitis using extracorporeal life support combined with hemoadsorption device and continuous renal replacement therapy

INTRODUCTION: Necrotizing fasciitis represents a life-threatening infectious condition that causes spreading necrotisis of superficial fascia and subcutaneous cellular tissues. We describe the case of a patient diagnosed with septic and toxic shocks leading to multiple organ failure successfully treated with a combination of extracorporeal life support, continuous renal replacement therapy, and a hemoadsorption device. METHODS: A 41-year-old patient presented with necrotizing fasciitis and multi-organ failure. Initial extracorporeal life support therapy was implanted, compensating for systolic failure. Due to acute renal failure that persisted in time, continuous renal replacement therapy was added. Despite these treatments and as a last attempt to control the septic condition, a CytoSorb hemoadsorption device was installed in parallel to the extracorporeal life support circuit and two sessions were run. RESULTS: During the days following CytoSorb treatment, hemodynamic stabilization was observed, as well as normalization of lactic acidosis and blood parameters. CONCLUSION: This case describes the successful use of CytoSorb with continuous renal replacement therapy and extracorporeal life support in a combined way to overcome a critical phase of septic shock in a young adult patient. This combination of treatments turned out to be efficient for this patient in the context of necrotizing fasciitis

Decisional role of the dorsolateral prefrontal cortex in ocular motor behaviour

Three patients with a unilateral cortical lesion affecting the dorsolateral prefrontal cortex (DLPFC), i.e. Brodmann area 46, were tested using different paradigms of reflexive saccades (gap and overlap tasks), intentional saccades (antisaccades, memory‐guided and predictive saccades) and smooth pursuit movements. Visually guided saccades with gap and overlap, latency of correct antisaccades and memory‐guided saccades and the gain of smooth pursuit were normal, compared with controls. These results confirm our anatomical data showing that the adjacent frontal eye field (FEF) was unimpaired in these patients. The specific pattern of abnormalities after a unilateral DLPFC lesion, compared with that of the FEF lesions previously reported, consists mainly of: (i) a bilateral increase in the percentage of errors in the antisaccade task (misdirected reflexive saccades); (ii) a bilateral increase in the variable error in amplitude, without significant decrease in the gain, in the memory‐guided saccade task; and (iii) a bilateral decrease in the percentage of anticipatory saccades in the predictive task. Taken together, these results suggest that the DLPFC plays a crucial role in the decisional processes, preparing saccades by inhibiting unwanted reflexive saccades (inhibition), maintaining memorized information for ongoing intentional saccades (short‐term spatial memory) or facilitating anticipatory saccades (prediction), depending upon current external environmental and internal circumstance

TLR3 MATURATION, LOCALISATION AND APOPTOTIC ROLE IN CANCER

Oral Communication presented at the ";Forum des Jeunes Chercheurs";, Brest (France) 2011

A new straight line reconstruction methodology from multi-spectral stereo aerial images

In this study, a new methodology for the reconstruction of line features from multispectral stereo aerial images is presented. We take full advantage of the existing multispectral information in aerial images all over the steps of pre-processing and edge detection. To accurately describe the straight line segments, a principal component analysis technique is adapted. The line to line correspondences between the stereo images are established using a new pair-wise stereo matching approach. The approach involves new constraints, and the redundancy inherent in pair relations gives us a possibility to reduce the number of false matches in a probabilistic manner. The methodology is tested over three different urban test sites and provided good results for line matching and reconstruction

SECOND ITERATION OF PHOTOGRAMMETRIC PIPELINE TO ENHANCE THE ACCURACY OF IMAGE POSE ESTIMATION

In classical photogrammetric processing pipeline, the automatic tie point extraction plays a key role in the quality of achieved results. The image tie points are crucial to pose estimation and have a significant influence on the precision of calculated orientation parameters. Therefore, both relative and absolute orientations of the 3D model can be affected. By improving the precision of image tie point measurement, one can enhance the quality of image orientation. The quality of image tie points is under the influence of several factors such as the multiplicity, the measurement precision and the distribution in 2D images as well as in 3D scenes. In complex acquisition scenarios such as indoor applications and oblique aerial images, tie point extraction is limited while only image information can be exploited. Hence, we propose here a method which improves the precision of pose estimation in complex scenarios by adding a second iteration to the classical processing pipeline. The result of a first iteration is used as a priori information to guide the extraction of new tie points with better quality. Evaluated with multiple case studies, the proposed method shows its validity and its high potiential for precision improvement