A large time-step and well-balanced Lagrange-Projection type scheme for the shallow-water equations

This work focuses on the numerical approximation of the Shallow Water Equations (SWE) using a Lagrange-Projection type approach. We propose to extend to this context recent implicit-explicit schemes developed in the framework of compressibleflows, with or without stiff source terms. These methods enable the use of time steps that are no longer constrained by the sound velocity thanks to an implicit treatment of the acoustic waves, and maintain accuracy in the subsonic regime thanks to an explicit treatment of the material waves. In the present setting, a particular attention will be also given to the discretization of the non-conservative terms in SWE and more specifically to the well-known well-balanced property. We prove that the proposed numerical strategy enjoys important non linear stability properties and we illustrate its behaviour past several relevant test cases

Shape sensitivity analysis in aerodynamics using an isogeometric Discontinuous Galerkin method

International audienceThe sensitivity equation method aims at estimating the derivative of the solution of partial differential equations with respect to a parameter of interest. The objective of this work is to investigate the ability of an isogeometric Discontinuous Galerkin (DG) method to evaluate accurately sensitivities with respect to shape parameters originating from Computer-Aided Design (CAD), in the context of compressible aerodynamics. The isogeometric DG method relies on Non- Uniform Rational B-Spline representations, which allow to define a high-order numerical scheme for Euler/Navier-stokes equations, fully consistent with CAD geometries. We detail how this formulation can be exploited to construct an efficient and accurate approach to evaluate shape sensitivities. A particular attention is paid to the treatment of boundary conditions for sensitivities, which are more tedious in the case of geometrical parameters. The proposed methodology is first verified on a test- case with analytical solution and then applied to two more demanding problems, that concern the inviscid flow around an airfoil with its camber as shape parameter and the unsteady viscous flow around a three-element airfoil with the positions of slat and flap as parameters

A NURBS-based Discontinuous Galerkin method for CAD compliant flow simulations

International audienceIn this work, we explain how a classical nodal Discontinuous Galerkin (DG) method for conservation laws can be modified to be geometrically exact with respect to CAD (Computer-Aided Design) data. The proposed approach relies on the use of rational Bézier elements, that can exactly match geometries defined by NURBS (Non-Uniform Rational B-Splines) after some basic transformations. It has been found convenient to use the same basis to describe the solution, yielding a so-called isogeometric formulation. The resulting method exhibits optimal convergence rates and facilitates couplings with geometry, e.g. for local refinement, shape sensitivity analysis, or moving computational domains. Illustrations are provided for two-dimensional compressible Euler and Navier-Stokes equations

Understanding multivalent effects in glycosidase inhibition using C-glycoside click clusters as molecular probes

The synthesis of the first examples of multivalent C-glycosides based on C60-fullerene or β-cyclodextrin cores by way of Cu(I)-catalyzed azide–alkyne cycloadditions is reported. These compounds were designed as molecular probes to understand the mechanisms underlying the outstanding multivalent effects observed in glycosidase inhibition. The inhibition results obtained support a multivalent-binding model based on two scenarios both involving nonspecific interactions and varying by the presence or the absence of active site specific interactions. The magnitude of the multivalent effect obtained depends on the identity of the glycosidase involved and more specifically on the accessibility of its catalytic active site. Large inhibitory multivalent effects can be obtained when both glycosidase active sites and non-catalytic sites at the protein surface are involved in binding events. On the other hand, nonspecific interactions alone are not sufficient to achieve relative affinity enhancements exceeding a simple statistical effect (i.e., a relative inhibition potency not better than one on a valence-corrected basis).Ministerio de Economía y Competitividad de España (MINECO) y Fondos Europeos de Desarrollo Regional (FEDER y FSE). SAF2013-44021-

Seroprevalence of Trypanosoma cruzi in a population of pregnant women and evaluation of their knowledge about Chagas Disease and its vectors

This study aimed at determining prevalence of anti-Trypanosoma cruzi antibodies in pregnant women in the extreme south of Brazil and at evaluating their knowledge about Chagas Disease (CD) and its vectors. The study was carried out in Pelotas, Rio Grande do Sul (RS) state, Brazil. The Chemiluminescent Microparticle Immunoassay (CMIA) was used for the triage and, when it was reagent, results were confirmed by the Indirect Immunofluorescence Assay (IFA). A semi-structured questionnaire was applied to evaluate patients’ knowledge. The Chi-squared test was used for evaluating correlations among variables under study while an Odds Ratio was conducted when associations were statistically significant. Only 33 (27.7%) out of 119 pregnant women under investigation underwent the serological test to identify T. cruzi because the study was carried out in the worst phase of the COVID-19 pandemic. However, prevalence was 6.1% (2 cases). Only 26.9% of pregnant women were able to identify triatominae and 66.4% did not know that the heart could be affected by CD. Associations between variables “lived/have lived in a rural area” and “having found ‘kissing bugs’ in the household”; “high schooling level” and “knowing that CD causes heart disorders”; and “stating that they know what CD is” and “identifying triatominae” exhibited statistical significance. Results showed that the rate of positive pregnant women is high and needs attention, even though the size of the sample is a limiting factor. Besides, the patients’ lack of knowledge about the disease and its vectors shows the importance of educational interventions

Thermo-compositional diabatic convection in the atmospheres of brown dwarfs and in Earth's atmosphere and oceans

This is the author accepted manuscript. The final version is available from the American Astronomical Society / IOP Publishing via the DOI in this record.The simulation outputs are available at http://opendata.erc-atmo.euBy generalizing the theory of convection to any type of thermal and compositional source terms (diabatic processes), we show that thermohaline convection in Earth oceans, fingering convection in stellar atmospheres, and moist convection in Earth atmosphere are deriving from the same general diabatic convective instability. We show also that "radiative convection" triggered by CO/CH4 transition with radiative transfer in the atmospheres of brown dwarfs is analog to moist and thermohaline convection. We derive a generalization of the mixing length theory to include the effect of source terms in 1D codes. We show that CO/CH4 radiative convection could significantly reduce the temperature gradient in the atmospheres of brown dwarfs similarly to moist convection in Earth atmosphere thus possibly explaining the reddening in brown-dwarf spectra. By using idealized two-dimensional hydrodynamic simulations in the Ledoux unstable regime, we show that compositional source terms can indeed provoke a reduction of the temperature gradient. The L/T transition could be explained by a bifurcation between the adiabatic and diabatic convective transports and could be seen as a giant cooling crisis: an analog of the boiling crisis in liquid/steam-water convective flows. This mechanism with other chemical transitions could be present in many giant and earth-like exoplanets. The study of the impact of different parameters (effective temperature, compositional changes) on CO/CH4 radiative convection and the analogy with Earth moist and thermohaline convection is opening the possibility to use brown dwarfs to better understand some aspects of the physics at play in the climate of our own planet.Science and Technology Facilities Council (STFC

Cartilha educativa para auxiliar no enfrentamento da doença de Chagas no Rio Grande do Sul, Brasil / Educational booklet to help fight Chagas disease in Rio Grande do Sul, Brazil

Introdução: As tecnologias educacionais em saúde são consideradas ferramentas inovadoras, capazes de fomentar a discussão e disseminação de conhecimentos sobre a doença de Chagas (DCH), estimulando assim, uma comunicação mais eficiente e acessível entre os sujeitos, através do estímulo ao autocuidado, proporcionando uma melhor qualidade de vida aos indivíduos acometidos pela DCH. Objetivo: Descrever o processo de construção e divulgação de cartilha educativa sobre a DCH para a população do extremo sul do Rio Grande do Sul (RS), visando a promoção da saúde e prevenção da moléstia e os seus vetores. Método: Trata-se de um estudo qualitativo, metodológico, com foco descritivo no processo de elaboração de material educativo, e se apresenta o fluxograma empregado na sua elaboração. Resultado: produziu-se um instrumento elucidativo, ilustrado, disponível em cópias impressas e conteúdo digital, distribuído gratuitamente para a população. Constituído por frases, figuras e ilustrações no que concerne o combate e prevenção da doença. O material contou com 13 páginas e 9 ilustrações. Conclusão: Julga-se que a cartilha possui conteúdo informativo relevante, devendo ser considerada uma ferramenta auxiliadora no contexto das atividades educativas e na prática clínica, sendo capaz de sensibilizar a população alvo e contribuir no enfrentamento da DCH