eXtended hybridizable discontinuous Galerkin for incompressible flow problems with unfitted meshes and interfaces

The eXtended hybridizable discontinuous Galerkin (X-HDG) method is developed for the solution of Stokes problems with void or material interfaces. X-HDG is a novel method that combines the hybridizable discontinuous Galerkin (HDG) method with an eXtended finite element strategy, resulting in a high-order, unfitted, superconvergent method, with an explicit definition of the interface geometry by means of a level-set function. For elements not cut by the interface, the standard HDG formulation is applied, whereas a modified weak form for the local problem is proposed for cut elements. Heaviside enrichment is considered on cut faces and in cut elements in the case of bimaterial problems. Two-dimensional numerical examples demonstrate that the applicability, accuracy, and superconvergence properties of HDG are inherited in X-HDG, with the freedom of computational meshes that do not fit the interfacesPeer ReviewedPostprint (author's final draft

Structural Differences in Rural Food Poverty between Female and Male-Headed Households

This article explores differences among female-headed households (FHHs) and male-headed households (MHHs) in terms of food poverty in Cameroon, Laos, Madagascar, Mauritania, and Tanzania. Stochastic dominance analysis shows that FHHs are more likely to be food poor related to MHHs, though this trend is less clear when looking only at food poor households. This ambiguity was clarified using discriminant function analysis. The results show that both female and male food poor households face the same obstacles to rural employment across the countries; barriers to access to land, productive assets, education, remittances and over-dependence on subsistence agriculture. Although further research is required to account for gender differences in social, cultural, political and economic status, these results suggest that greater attention should be paid to long-term policies in ensuring access to quality education, land and other assets to all food insecure households, not only to FHHs to the possible detriment of food poor MHHs. In the short-term cash or food-for-assets and school feeding programmes can also provide important springboards for larger scale changes in national policies that are central to escaping the food poverty trap

eXtended Hybridizable Discontinous Galerkin (X-HDG) Method for Linear Convection-Diffusion Equations on Unfitted Domains

In this work, we propose a novel strategy for the numerical solution of linear convection diffusion equation (CDE) over unfitted domains. In the proposed numerical scheme, strategies from high order Hybridized Discontinuous Galerkin method and eXtended Finite Element method is combined with the level set definition of the boundaries. The proposed scheme and hence, is named as eXtended Hybridizable Discontinuous Galerkin (XHDG) method. In this regard, the Hybridizable Discontinuous Galerkin (HDG) method is eXtended to the unfitted domains; i.e, the computational mesh does not need to fit to the domain boundary; instead, the boundary is defined by a level set function and cuts through the background mesh arbitrarily. The original unknown structure of HDG and its hybrid nature ensuring the local conservation of fluxes is kept, while developing a modified bilinear form for the elements cut by the boundary. At every cut element, an auxiliary nodal trace variable on the boundary is introduced, which is eliminated afterwards while imposing the boundary conditions. Both stationary and time dependent CDEs are studied over a range of flow regimes from diffusion to convection dominated; using high order $(p \leq 4)$ XHDG through benchmark numerical examples over arbitrary unfitted domains. Results proved that XHDG inherits optimal $(p + 1)$ and super $(p + 2)$ convergence properties of HDG while removing the fitting mesh restriction

Structural Differences in Rural Food Poverty between Female and Male-Headed Households

This article explores differences among female-headed households (FHHs) and male-headed households (MHHs) in terms of food poverty in Cameroon, Laos, Madagascar, Mauritania, and Tanzania. Stochastic dominance analysis shows that FHHs are more likely to be food poor related to MHHs, though this trend is less clear when looking only at food poor households. This ambiguity was clarified using discriminant function analysis. The results show that both female and male food poor households face the same obstacles to rural employment across the countries; barriers to access to land, productive assets, education, remittances and over-dependence on subsistence agriculture. Although further research is required to account for gender differences in social, cultural, political and economic status, these results suggest that greater attention should be paid to long-term policies in ensuring access to quality education, land and other assets to all food insecure households, not only to FHHs to the possible detriment of food poor MHHs. In the short-term cash or food-for-assets and school feeding programmes can also provide important springboards for larger scale changes in national policies that are central to escaping the food poverty trap

Extended hybridizable discontinuous galerkin with heaviside enrichment for heat bimaterial problems

The final publication is available at link.springer.comA novel strategy for the hybridizable discontinuous Galerkin (HDG) solution of heat bimaterial problems is proposed. It is based on eXtended finite element philosophy, together with a level set description of interfaces. Heaviside enrichment on cut elements and cut faces is used to represent discontinuities across the interface. A suitable weak form for the HDG local problem on cut elements is derived, accounting for the discontinuous enriched approximation, and weakly imposing continuity or jump conditions over the material interface. The computational mesh is not required to fit the interface, simplifying and reducing the cost of mesh generation and, in particular, avoiding continuous remeshing for evolving interfaces. Numerical experiments demonstrate that X-HDG keeps the accuracy of standard HDG methods in terms of optimal convergence and superconvergence.Peer ReviewedPostprint (author's final draft

Lack of Association Between Toll-like Receptor 2 Polymorphisms (R753Q and A-16934T) and Atopic Dermatitis in Children from Thrace Region of Turkey

Background: Atopic dermatitis is the most common chronic inflammatory skin disease. A complex interaction of both genetic and environmental factors is thought to contribute to the disease. Aims: To evaluate whether single nucleotide polymorphisms in the TLR2 gene c.2258C>T (R753Q) (rs5743708) and TLR2 c.-148+1614T>A (A-16934T) (rs4696480) (NM_0032643) are associated with atopic dermatitis in Turkish children. Study Design: Case-control study. Methods: The study was conducted on 70 Turkish children with atopic dermatitis aged 0.5-18 years. The clinical severity of atopic dermatitis was evaluated by the severity scoring of atopic dermatitis index. Serum total IgE levels, specific IgE antibodies to inhalant and food allergens were measured in both atopic dermatitis patients and controls, skin prick tests were done on 70 children with atopic dermatitis. Genotyping for TLR2 (R753Q and A-16934T) single nucleotide polymorphisms was performed in both atopic dermatitis patients and controls. Results: Cytosine-cytosine and cytosin-thymine genotype frequencies of the TLR2 R753Q single nucleotide polymorphism in the atopic dermatitis group were determined as being 98.6% and 1.4%, cytosine allele frequency for TLR2 R753Q single nucleotide polymorphism was determined as 99.29% and the thymine allele frequency was 0.71%, thymine-thymine, thymineadenine, and adenine-adenine genotype frequencies of the TLR2 A-16934T single nucleotide polymorphism were 24.3%, 44.3%, and 31.4%. The thymine allele frequency for the TLR2 A-16934T single nucleotide polymorphism in the atopic dermatitis group was 46.43%, and the adenine allele frequency was 53.57%, respectively. There was not statistically significant difference between the groups for all investigated polymorphisims (p>0.05). For all single nucleotide polymorphisms studied, allelic distribution was analogous among atopic dermatitis patients and controls, and no significant statistical difference was observed. No homozygous carriers of the TLR2 R753Q single nucleotide polymorphism were found in the atopic dermatitis and control groups. Conclusion: The TLR2 (R753Q and A-16934T) single nucleotide polymorphisms are not associated with atopic dermatitis in a group of Turkish patients