Space-mapping techniques applied to the optimization of a safety isolating transformer

Space-mapping optimization techniques allow to allign low-fidelity and high-fidelity models in order to reduce the computational time and increase the accuracy of the solution. The main idea is to build an approximate model from the difference of response between both models. Therefore the optimization process is computed on the surrogate model. In this paper, some recent approaches of space-mapping techniques such as agressive-space-mapping, output-mapping and manifold-mapping algorithms are applied to optimize a safety insulating transformer. The electric, magnetic and thermal phenomena of the device are modeled by an analytical model and a 3D finite element model. It is considered as a benchmark for multi-level optimization to test different algorithms

Characterization of ENU-induced mutations in red blood cell structural proteins

Murine models with modified gene function as a result of N-ethyl-N-nitrosourea (ENU) mutagenesis have been used to study phenotypes resulting from genetic change. This study investigated genetic factors associated with red blood cell (RBC) physiology an

Fibroblastic niches prime T cell alloimmunity through Delta-like Notch ligands.

Alloimmune T cell responses induce graft-versus-host disease (GVHD), a serious complication of allogeneic bone marrow transplantation (allo-BMT). Although Notch signaling mediated by Delta-like 1/4 (DLL1/4) Notch ligands has emerged as a major regulator of GVHD pathogenesis, little is known about the timing of essential Notch signals and the cellular source of Notch ligands after allo-BMT. Here, we have shown that critical DLL1/4-mediated Notch signals are delivered to donor T cells during a short 48-hour window after transplantation in a mouse allo-BMT model. Stromal, but not hematopoietic, cells were the essential source of Notch ligands during in vivo priming of alloreactive T cells. GVHD could be prevented by selective inactivation of Dll1 and Dll4 in subsets of fibroblastic stromal cells that were derived from chemokine Ccl19-expressing host cells, including fibroblastic reticular cells and follicular dendritic cells. However, neither T cell recruitment into secondary lymphoid organs nor initial T cell activation was affected by Dll1/4 loss. Thus, we have uncovered a pathogenic function for fibroblastic stromal cells in alloimmune reactivity that can be dissociated from their homeostatic functions. Our results reveal what we believe to be a previously unrecognized Notch-mediated immunopathogenic role for stromal cell niches in secondary lymphoid organs after allo-BMT and define a framework of early cellular and molecular interactions that regulate T cell alloimmunity

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees

Comparison between numerical and experimental results of the hybrid members subjected to bending and shear

International audienceThis paper presents experimental and numerical results of the hybrid members with several encased steel profiles subjected to bending and shear. These results are compared with each other on the load-bearing capacity, the strain distribution, the stress distribution, the slip distribution, the crack pattern, the failure modes. These steel-concrete composite structural elements belong to the so-called “hybrid” structures which are neither reinforced concrete structure in the sense of Eurocode 2, nor steel-concrete composite structures in the sense of Eurocode 4. Currently, there is no design calculation guide of the resistance for this type of structure in international standards. Therefore, the comparison between numerical and experimental results is performed to point out the mechanism of the load transfer and failure taking place within the hybrid members subjected to bending and shear. It is the basis for calibrating the proposed design method for hybrid members reinforced by several steel profiles. The six hybrid member specimens were prepared and tested at the Structures Laboratory of INSA Rennes, France. The structural response of all hybrid members specimens were simulated by a full 3D finite element model using the Abaqus software. © 2018, Springer Nature Singapore Pte Ltd

Screening Australian turf and pasture bermudagrasses (Cynodon dactylon) for salt tolerance: Association between salt tolerance and drought resistance

A large collection of over 1000 naturalised Australian bermudagrasses (Cynodon dactylon) was assembled. Previous research indicated that a subset of the grasses collected from Australian Mediterranean environments were drought resistant and characterised by large rhizomes that could be a potential source of nutrients, water and carbohydrates when these grasses grow under saline conditions. The objective of this research was to test the salinity tolerance of 12 bermudagrass genotypes with different levels of drought resistance using a flood and drain, sand-solution hydroponic system. Eight salt treatments were imposed ranging from 1.3 to 21 dS m-1 (corresponding 0 to 175 mM NaCl) for up to 17 weeks. Salinity tolerance among genotypes was categorised on the basis of 50% reduction in cumulative clipping yields, verdure and root biomass, and green cover, relative to the control treatment. There was no correlation between salt tolerance and drought resistance (r = -0.079 to 0.572), although some drought-resistant grasses did have excellent salt tolerance, such as entries MED1 and MED3. At 21 dS m-1, most grasses not only maintained over 50% total biomass but also retained over 70% green cover, relative to the control treatment, and were considered as highly salt tolerant. These salt-tolerant grasses have great potential for stabilising and revegetating saline and/or sodic soils.T.V. Tran, S. Fukai, Y. Zhou, C.J. Lambride

Symmetry-breaking in cumulative measures of shapes of polymer models.

Using numerical simulations we investigate shapes of random equilateral open and closed chains, one of the simplest models of freely fluctuating polymers in a solution. We are interested in the 3D density distribution of the modeled polymers where the polymers have been aligned with respect to their three principal axes of inertia. This type of approach was pioneered by Theodorou and Suter in 1985. While individual configurations of the modeled polymers are almost always nonsymmetric, the approach of Theodorou and Suter results in cumulative shapes that are highly symmetric. By taking advantage of asymmetries within the individual configurations, we modify the procedure of aligning independent configurations in a way that shows their asymmetry. This approach reveals, for example, that the 3D density distribution for linear polymers has a bean shape predicted theoretically by Kuhn. The symmetry-breaking approach reveals complementary information to the traditional, symmetrical, 3D density distributions originally introduced by Theodorou and Suter

Role of free Cys121 in stabilization of bovine beta-lactoglobulin B

International audienc