Towards goal-oriented mesh adaptation for fluid-structure interaction

In order to address fluid-structure interaction, we present an a priori analysis for an ALE compressible flow model. This analysis is the key for an anisotropic metricbased mesh adaptation

Dynamique des paysages méditerranéens : un siècle de réinstallation naturelle de la forêt dans le bassin versant de l'Hérault.

Au milieu du 19ème siècle, la densité maximale de la population s'accompagne d'une utilisation intensive des boisements ; ensuite la phase de déprise aboutit à une recolonisation par la forêt

Dynamic and hybrid variational multiscale models for the simulation of bluff-body flows on unstructured grids

The computation of massively separated flows is a challenging problem of particular in- terest in industrial applications. For the purpose of properly simulating these complex flows on not too heavy unstructured meshes as usually employed in industry, appropriate numerical and turbulent models must be used. In the present work, the computation of the flow past a circular cylinder at different Reynolds numbers is chosen as benchmark. The spatial discretization is based on a mixed finite element/finite volume formulation on unstructured grids. The numerical dissipation of the upwind scheme is made of sixth-order space derivatives in order to limit as far as possible the interactions between numerical and subgrid scale (SGS) dissipation, which could deteriorate the accuracy of the results [4]. A variational multi-scale large-eddy simulation (VMS-LES) with dynamic SGS models and a RANS/VMS-LES model are evaluated on the proposed benchmark for subcritical and supercritical flow regimes respectively (see Fig. 1 and Tab. 1). In the VMS-LES used in this work, the separation between the large and the small resolved scales is obtained through a variational projection operator based on spatial average on agglomerated cells [1]. The dynamic procedure allows the adaptation of the constant of the SGS model to the spatial and temporal variation of the flow characteristics, while the VMS formulation restricts the SGS model effects to the smallest resolved scales. The dynamic versions of the Smagorinsky and of the WALE SGS models are considered herein. The non-dynamic counterparts of these SGS models are also used in order to evaluate the impact of dy- namic SGS modeling in the considered VMS-LES approach for the simulation of massively separated flows. However, the Reynolds number range useful for LES-like simulation is limited as LES grid needs to be sufficiently fine to resolve a significant part of the turbulence scales. With the aim of simulating high Reynolds number flows, it is considered in the present work a hybridization strategy using a blending parameter, such that a VMS- LES simulation is obtained where the grid resolution is fine enough to resolve a significant part of the turbulence fluctuations [2], while a RANS model is acting in the regions of coarse grid resolution, as, for instance, near the body surface

Photographie diachronique et changement des paysages : un siècle de dynamique naturelle de la forêt à Saint Bauzille de Putois, vallée de l'Hérault

La comparaison de photographies anciennes (prises au début du siècle) et de photographies actuelles des mêmes paysages met en évidence de manière souvent spectaculaire les changements des paysages méditerranéens à la suite de l'exode rural. Ceux-ci se transforment progressivement en une mosaïque à deux éléments, forêts et culture, où les formations végétales intermédiaires tendent à disparaître. Ces changements mettent aussi en évidence la grande résilience des peuplements forestiers étudiée

AD-based perturbation methods for uncertainties and errors

International audienceThe progress of Automatic Differentiation ({\bf AD}) and its impact on perturbation methods is the object of this paper. AD studies show an important activity for developing methods addressing the management of modern CFD kernels, taking into account the language evolution, and intensive parallel computing. The evaluation of a posteriori error analysis and of resulting correctors will be addressed. Recents works in the AD-based contruction of second-derivatives for building reduced-order models based on a Taylor formula will be presented on the test case of a steady compressible flow around an aircraft

Cell-bound complement activation products associate with lupus severity in SLE.

OBJECTIVES: To evaluate the association between lupus severity and cell-bound complement activation products (CB-CAPs) or low complement proteins C3 and C4. METHODS: All subjects (n=495) fulfilled the American College of Rheumatology (ACR) classification criteria for SLE. Abnormal CB-CAPs (erythrocyte-bound C4d or B-lymphocyte-bound C4d levels \u3e99th percentile of healthy) and complement proteins C3 and C4 were determined using flow cytometry and turbidimetry, respectively. Lupus severity was estimated using the Lupus Severity Index (LSI). Statistical analysis consisted of multivariable linear regression and groups comparisons. RESULTS: Abnormal CB-CAPs were more prevalent than low complement values irrespective of LSI levels (62% vs 38%, respectively, p CONCLUSION: Abnormalities in complement activation as measured by CB-CAPs are associated with increased LSI

Randomised prospective trial to assess the clinical utility of multianalyte assay panel with complement activation products for the diagnosis of SLE.

Objective: We compared the physician-assessed diagnostic likelihood of SLE resulting from standard diagnosis laboratory testing (SDLT) to that resulting from multianalyte assay panel (MAP) with cell-bound complement activation products (MAP/CB-CAPs), which reports a two-tiered index test result having 80% sensitivity and 86% specificity for SLE. Methods: Patients (n=145) with a history of positive antinuclear antibody status were evaluated clinically by rheumatologists and randomised to SDLT arm (tests ordered at the discretion of the rheumatologists) or to MAP/CB-CAPs testing arm. The primary endpoint was based on the change in the physician likelihood of SLE on a five-point Likert scale collected before and after testing. Changes in pharmacological treatment based on laboratory results were assessed in both arms. Statistical analysis consisted of Wilcoxon and Fisher\u27s exact tests. Results: At enrolment, patients randomised to SDLT (n=73, age=48±2 years, 94% females) and MAP/CB-CAPs testing arms (n=72, 50±2 years, 93% females) presented with similar pretest likelihood of SLE (1.42±0.06 vs 1.46±0.06 points, respectively; p=0.68). Post-test likelihood of SLE resulting from randomisation in the MAP/CB-CAPs testing arm was significantly lower than that resulting from randomisation to SDLT arm on review of test results (-0.44±0.10 points vs -0.19±0.07 points) and at the 12-week follow-up visit (-0.61±0.10 points vs -0.31±0.10 points) (p Conclusion: Our data suggest that MAP/CB-CAPs testing has clinical utility in facilitating SLE diagnosis and treatment decisions

6-thioguanine treatment in inflammatory bowel disease: A critical appraisal by a European 6-TG working party

Recently, the suggestion to use 6-thioguanine (6-TG) as an alternative thiopurine in patients with inflammatory bowel disease (IBD) has been discarded due to reports about possible (hepato) toxicity. During meetings arranged in Vienna and Prague in 2004, European experts applying 6-TG further on in IBD patients presented data on safety and efficacy of 6-TG. After thorough evaluation of its risk-benefit ratio, the group consented that 6-TG may still be considered as a rescue drug in stringently defined indications in IBD, albeit restricted to a clinical research setting. As a potential indication for administering 6-TG, we delineated the requirement for maintenance therapy as well as intolerance and/or resistance to aminosalicylates, azathioprine, 6-mercaptopurine, methotrexate and infliximab. Furthermore, indications are preferred in which surgery is thought to be inappropriate. The standard 6-TG dosage should not exceed 25 mg daily. Routine laboratory controls are mandatory in short intervals. Liver biopsies should be performed after 6-12 months, three years and then three-yearly accompanied by gastroduodenoscopy, to monitor for potential hepatotoxicity, including nodular regenerative hyperplasia (NRH) and veno-occlusive disease (VOD). Treatment with 6-TG must be discontinued in case of overt or histologically proven hepatotoxicity. Copyright (c) 2006 S. Karger AG, Basel