208 research outputs found

    Uncompensated magnetization and exchange-bias field in La0.7_{0.7}Sr0.3_{0.3}MnO3_3/YMnO3_3 bilayers: The influence of the ferromagnetic layer

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    We studied the magnetic behavior of bilayers of multiferroic and nominally antiferromagnetic o-YMnO3_3 (375~nm thick) and ferromagnetic La0.7_{0.7}Sr0.3_{0.3}MnO3_3 and La0.67_{0.67}Ca0.33_{0.33}MnO3_3 (8225 8 \ldots 225~nm), in particular the vertical magnetization shift MEM_E and exchange bias field HEH_E for different thickness and magnetic dilution of the ferromagnetic layer at different temperatures and cooling fields. We have found very large MEM_E shifts equivalent to up to 100\% of the saturation value of the o-YMO layer alone. The overall behavior indicates that the properties of the ferromagnetic layer contribute substantially to the MEM_E shift and that this does not correlate straightforwardly with the measured exchange bias field HEH_E.Comment: 10 figures, 8 page

    CARDigues: an integrated tool for levee system diagnosis and assessment

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    In December 2007, a French decree related to hydraulic structures (levees and dams) has introduced for owners the necessity to produce a hazard study for each levee system. On the river Loire, three major class A* state levee systems are present and protect three main urban areas, Orléans, Tours and Authion representing some 240 000 inhabitants. Around 40 class B* and C* levee systems are also present on the river Loire and its tributaries representing 600 km of levees and requiring such hazard studies. In order to have a homogenous method to do these specific risk assessment studies on river Loire levees, a new model named CARDigues (for Levee Breach Hazard Calculation) was developed in a partnership with DREAL Centre-Val de Loire, Cerema and Irstea. This model enables to approach the probability of failure on every levee sections and to integrate and cross different “stability” parameters (topography, embedded structures, geology), hydraulic solicitations and observations from visual inspections or instrumentation results considered as disorders (seepage, burrowing animals, vegetation, pipes, etc.). This model and integrated tool CARDigues enables to check for each levee section, the probability of appearance and rupture of five breaching scenarios initiated by: overflowing, internal erosion, slope instability, external erosion and uplift. It has been recently updated and has been applied on several levee systems by different contractors. The article presents the CARDigues model (V28.00) with examples on river Loire and how it is currently used for a relevant and global levee system diagnosis and assessment. Levee reinforcement or improvement management is also a perspective of applications for this model CARDigues. (* levee classes are function of levee height and protected population

    PlcRa, a new quorum-sensing regulator from Bacillus cereus, plays a role in oxidative stress responses and cysteine metabolism in stationary phase

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    We characterized a new quorum-sensing regulator, PlcRa, which is present in various members of the B. cereus group and identified a signaling heptapeptide for PlcRa activity: PapRa7. We demonstrated that PlcRa is a 3D structural paralog of PlcR using sequence analysis and homology modeling. A comparison of the transcriptomes at the onset of stationary phase of a ¿plcRa mutant and the wild-type B. cereus ATCC 14579 strain showed that 68 genes were upregulated and 49 genes were downregulated in the ¿plcRa mutant strain (>3-fold change). Genes involved in the cysteine metabolism (putative CymR regulon) were downregulated in the ¿plcRa mutant strain. We focused on the gene with the largest difference in expression level between the two conditions, which encoded -AbrB2- a new regulator of the AbrB family. We demonstrated that purified PlcRa bound specifically to the abrB2 promoter in the presence of synthetic PapRa7, in an electrophoretic mobility shift assay. We further showed that the AbrB2 regulator controlled the expression of the yrrT operon involved in methionine to cysteine conversion. We found that the ¿plcRa mutant strain was more sensitive to hydrogen peroxide- and disulfide-induced stresses than the wild type. When cystine was added to the culture of the ¿plcRa mutant, challenged with hydrogen peroxide, growth inhibition was abolished. In conclusion, we identified a new RNPP transcriptional regulator in B. cereus that activated the oxidative stress response and cysteine metabolism in transition state cells

    How Do Employees Perceive Corporate Responsibility? Development and Validation of a Multidimensional Corporate Stakeholder Responsibility Scale

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    Recent research on the microfoundations of corporate social responsibility (CSR) has highlighted the need for improved measures to evaluate how stakeholders perceive and subsequently react to CSR initiatives. Drawing on stakeholder theory and data from five samples of employees (N = 3,772), the authors develop and validate a new measure of corporate stakeholder responsibility (CStR), which refers to an organization’s context-specific actions and policies designed to enhance the welfare of various stakeholder groups by accounting for the triple bottom line of economic, social, and environmental performance; it is conceptualized as a superordinate, multidimensional construct. Results from exploratory factor analyses, first- and second-order confirmatory factor analyses, and structural equation modeling provide strong evidence of the convergent, discriminant, incremental, and criterion-related validities of the proposed CStR scale. Two-wave longitudinal studies further extend prior theory by demonstrating that the higher-order CStR construct relates positively and directly to organizational pride and perceived organizational support, as well as positively and indirectly to organizational identification, job satisfaction, and affective commitment, beyond the contribution of overall organizational justice, ethical climate, and prior measures of perceived CSR

    Going it alone won’t work! The relational imperative for social innovation in social enterprises

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    Shifts in the philosophy of the “state” and a growing emphasis on the “Big Society” have placed an increasing onus on a newly emerging organizational form, social enterprises, to deliver innovative solutions to ease societal issues. However, the question of how social enterprises manage the process of social innovation remains largely unexplored. Based on insights from both in-depth interviews and a quantitative empirical study of social enterprises, this research examines the role of stakeholder relationships in supporting the process of social innovation within social enterprises. We find that social enterprises are adept at working with their stakeholders in the ideation stage of social innovation. In contrast, they often fail to harness knowledge and expertise from their partners during the social innovation implementation phase. Consequently, we propose a social innovation–stakeholder relationship matrix that provides social enterprises in particular with insight for developing stakeholder relationships to achieve their social innovation missions

    Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

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    Stakeholder Relationships and Social Welfare: A Behavioral Theory of Contributions to Joint Value Creation

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    Firms play a crucial role in furthering social welfare through their ability to foster stakeholders’ contributions to joint value creation, i.e., value creation that involves a public-good dilemma due to high task and outcome interdependence - leading to what economists have labeled the ‘team production problem’. We build on relational models theory to examine how individual stakeholders’ contributions to joint value creation are shaped by stakeholders’ mental representations of their relationships with the other participants in value creation, and how these mental representations are affected by the perceived behavior of the firm. Stakeholder theory typically contrasts a broadly-defined ‘relational’ approach to stakeholder management with a ‘transactional’ approach based on the price mechanism - and has argued that the former is more likely to contribute to social welfare than the latter. Our theory supports this prediction for joint value creation, but also implies that the dichotomy on which it is based is too coarse-grained: there are three distinct ways to trigger higher contributions to joint value creation than through a ‘transactional’ approach. Our theory also helps explain the tendency for firms and their stakeholders to converge on ‘transactional’ relationships, despite their relative inefficiency in the context of joint value creation
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