Composition-induced structural phase transitions in the (Ba1xLax)2In2O5+x (0pxp0.6) system

Composition-induced structural phase changes across the high temperature, fast oxide ion conducting (Ba1xLax)2In2O5+x, 0pxp0.6, system have been carefully analysed using hard mode infrared (IR) powder absorption spectroscopy, X-ray powder diffraction and electron diffraction. An orthorhombic brownmillerite to three-dimensionally disordered cubic perovskite phase transition in this system is signalled by a drastic change in slope of both wavenumber and average line widths of IR spectra as a function of composition. Some evidence is found for the existence of an intermediate tetragonal phase (previously reported to exist from electron diffraction data) around x 0:2: The new spectroscopic data have been used to compare microscopic and macroscopic strain parameters arising from variation in composition. The strain and spectroscopic data are consistent with firstorder character for the tetragonal-orthorhombic transition, while the cubic-tetragonal transition could be continuous. Differences between the variation with composition of spectral parameters and of macroscopic strain parameters are consistent with a substantial order/disorder component for the transitions. There is also evidence for precursor effects within the cubic structure before symmetry is broken

A physically-based and fully coupled model of elasto-plasticity and damage for dynamic failure in ductile metals

It is well established that spall fracture and other rapid failures in ductile materials are often dominated by nucleation and growth ofmicro-voids. In the present work, a mechanistic model for failure by cumulative nucleation and growth of voids is fully coupled with the thermoelastoplasticconstitutive equations of the Mechanical Threshold Stress (MTS) which is used to model the evolution of the flow stress. Thedamage modeling includes both ductile and brittle mechanisms. It accounts for the effects of inertia, rate sensitivity, fracture surface energy, andnucleation frequency. The MTS model used for plasticity includes the superposition of different thermal activation barriers for dislocationmotion. Results obtained in the case of uncoupled and coupled model of plasticity and damage from the simulations of the planar impact withcylindrical target, are presented and compared with the experimental results for OFHC copper. This comparison shows the model capabilities inpredicting the experimentally measured free surface velocity profile as well as the observed spall and other damage patterns in the material underimpact loading. These results are obtained using the finite element code Abaqus/Explicit

The impact of restricted diet on brain function using BOLD-fMRI

We investigated the effect of a restricted diet model on activity in the human motor cortex using functional magnetic resonance imaging (fMRI). Two series of blood oxygenation level-dependent (BOLD)-fMRI measurements were made in healthy subjects performing simple motor tasks using their right hands. The first series was done 5-10days prior to the restricted diet schedule (controls), and the second series was performed after 25-28days of restricted diet, in the form of a religious fast (Ramadan). The size and intensity of the activated area in the motor cortex increased during the time of restricted diet versus the controls. We conclude that restricted diet has a significant effect on cerebral activity, as shown by BOLD-fMRI, although the exact relationship between the images and neuronal activity due to the restricted diet is still to be determine

Simulation of the Taylor impact test and analysis of damage evolution using a nucleation and growth based approach

International audienceComputational modeling of the Taylor impact test, using OFHC copper rods are carried out for two impact velocities (260 m/s and 365 m/s). The aim of this work is to demonstrate the efficiency of the recently proposed material model for dynamic plasticity and failure for metals. This model combines the use of a damage approach based on void nucleation and growth, with the Mechanical Threshold Stress (MTS) model for the evolution of the flow stress in isotropic plasticity. The proposed approach is implemented in the finite element code ABAQUS/Explicit via a user material subroutine and the symmetric Taylor impact test, using copper rods, is simulated. The predicted results are compared to the experimental results reported in the open literature and good agreement is found for both shape change and damage distribution

Clinico-radiological criteria versus GeneXpert for diagnosis of pediatric tuberculosis

Background: Diagnosing tuberculosis in children remains a challenge especially in low-income countries. The aim of this study was to assess the performance of the scoring system combined to chest x-ray images compared to GeneXpert for diagnosis of pediatric tuberculosis.Methods: A retrospective diagnostic accuracy study was carried out on hospitalized children aged 0 to 14 years old, tuberculosis suspect in the pediatric department of the Tsaralalana mother child university hospital center from August 2018 to June 2020.Results: Fifty-one medical files were retained. The mean age was 4±2 years old with a sex ratio of 1.55. The reason for consultation was dominated by respiratory signs (56.9%). The GeneXpert was positive in 58.9% of cases. The chest X-ray images were pathological in all cases, dominated by images of condensation or infiltration (72.5%). WHO score was positive (≥7) in 72.5% of cases. The clinico-radiological criteria had a sensitivity of 13.3-63.3%, a specificity of 61.9-95.2%, positive predictive values of 1.5-6.9% and negative predictive values of 98.8-99.3%.Conclusion: Clinico-radiological criteria could be useful in individual diagnosis of pediatric tuberculosis

News discourses on distant suffering: A critical discourse analysis of the 2003 SARS outbreak

News carries a unique signifying power, a power to represent events in particular ways (Fairclough, 1995). Applying Critical Discourse Analysis and Chouliaraki's theory on the mediation of suffering (2006), this article explores the news representation of the 2003 global SARS outbreak. Following a case-based methodology, we investigate how two Belgian television stations have covered the international outbreak of SARS. By looking into the mediation of four selected discursive moments, underlying discourses of power, hierarchy and compassion were unraveled. The analysis further identified the key role of proximity in international news reporting and supports the claim that Western news media mainly reproduce a Euro-American centered world order. This article argues that news coverage of international crises such as SARS constructs and maintains the socio-cultural difference between 'us' and 'them' as well as articulating global power hierarchies and a division of the world in zones of poverty and prosperity, danger and safety

Transformation-based spherical cloaks designed by an implicit transformation-independent method: theory and optimization

Based on the concept of the cloak generating function, we propose an implicit transformation-independent method for the required parameters of spherical cloaks without knowing the needed coordinate transformation beforehand. A non-ideal discrete model is used to calculate and optimize the total scattering cross-sections of different profiles of the generating function. A bell-shaped quadratic spherical cloak is found to be the best candidate, which is further optimized by controlling the design parameters involved. Such improved invisibility is steady even when the model is highly discretized.European Commission (European Network of Excellence 'METAMORPHOSE')Foundation for Fundamental Research (Belarus) (F08MS-06

In vivo antiviral efficacy of prenylation inhibitors against hepatitis delta virus

Hepatitis delta virus (HDV) can dramatically worsen liver disease in patients coinfected with hepatitis B virus (HBV). No effective medical therapy exists for HDV. The HDV envelope requires HBV surface antigen proteins provided by HBV. Once inside a cell, however, HDV can replicate its genome in the absence of any HBV gene products. In vitro, HDV virion assembly is critically dependent on prenyl lipid modification, or prenylation, of its nucleocapsid-like protein large delta antigen. To overcome limitations of current animal models and to test the hypothesis that pharmacologic prenylation inhibition can prevent the production of HDV virions in vivo, we established a convenient mouse-based model of HDV infection capable of yielding viremia. Such mice were then treated with the prenylation inhibitors FTI-277 and FTI-2153. Both agents were highly effective at clearing HDV viremia. As expected, HDV inhibition exhibited duration-of-treatment dependence. These results provide the first preclinical data supporting the in vivo efficacy of prenylation inhibition as a novel antiviral therapy with potential application to HDV and a wide variety of other viruses

Toward an Identification of Resources Influencing Habitat Use in a Multi-Specific Context

Interactions between animal behaviour and the environment are both shaping observed habitat use. Despite the importance of inter-specific interactions on the habitat use performed by individuals, most previous analyses have focused on case studies of single species. By focusing on two sympatric populations of large herbivores with contrasting body size, we went one step beyond by studying variation in home range size and identifying the factors involved in such variation, to define how habitat features such as resource heterogeneity, resource quality, and openness created by hurricane or forest managers, and constraints may influence habitat use at the individual level. We found a large variability among individual's home range size in both species, particularly in summer. Season appeared as the most important factor accounting for observed variation in home range size. Regarding habitat features, we found that (i) the proportion of area damaged by the hurricane was the only habitat component that inversely influenced roe deer home range size, (ii) this habitat type also influenced both diurnal and nocturnal red deer home range sizes, (iii) home range size of red deer during the day was inversely influenced by the biomass of their preferred plants, as were both diurnal and nocturnal core areas of the red deer home range, and (iv) we do not find any effect of resource heterogeneity on home range size in any case. Our results suggest that a particular habitat type (i.e. areas damaged by hurricane) can be used by individuals of sympatric species because it brings both protected and dietary resources. Thus, it is necessary to maintain the openness of these areas and to keep animal density quite low as observed in these hunted populations to limit competition between these sympatric populations of herbivores