357 research outputs found

    The Interaction of Genetic Background and Mutational Effects in Regulation of Mouse Craniofacial Shape.

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    Inbred genetic background significantly influences the expression of phenotypes associated with known genetic perturbations and can underlie variation in disease severity between individuals with the same mutation. However, the effect of epistatic interactions on the development of complex traits, such as craniofacial morphology, is poorly understood. Here, we investigated the effect of three inbred backgrounds (129X1/SvJ, C57BL/6J, and FVB/NJ) on the expression of craniofacial dysmorphology in mice (Mus musculus) with loss of function in three members of the Sprouty family of growth factor negative regulators (Spry1, Spry2, or Spry4) in order to explore the impact of epistatic interactions on skull morphology. We found that the interaction of inbred background and the Sprouty genotype explains as much craniofacial shape variation as the Sprouty genotype alone. The most severely affected genotypes display a relatively short and wide skull, a rounded cranial vault, and a more highly angled inferior profile. Our results suggest that the FVB background is more resilient to Sprouty loss of function than either C57 or 129, and that Spry4 loss is generally less severe than loss of Spry1 or Spry2 While the specific modifier genes responsible for these significant background effects remain unknown, our results highlight the value of intercrossing mice of multiple inbred backgrounds to identify the genes and developmental interactions that modulate the severity of craniofacial dysmorphology. Our quantitative results represent an important first step toward elucidating genetic interactions underlying variation in robustness to known genetic perturbations in mice

    Absorbing Boundary Conditions for the Two-Dimensional Schrödinger Equation with an Exterior Potential. Part I: Construction and a priori Estimates

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    International audienceThe aim of this paper is to construct some classes of absorbing boundary conditions for the two-dimensional Schrödinger equation with a time and space varying exterior potential and for general convex smooth boundaries. The construction is based on asymptotics of the inhomogeneous pseudodifferential operators defining the related Dirichlet-to-Neumann operator. Furthermore, \textit{a priori} estimates are developed for the truncated problems with various increasing order boundary conditions. The effective numerical approximation will be treated in a second paper

    Numerical Solution of Time-Dependent Nonlinear Schrödinger Equations Using Domain Truncation Techniques Coupled With Relaxation Scheme

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    International audienceThe aim of this paper is to compare different ways for truncating unbounded domains for solving general nonlinear one- and two-dimensional Schrödinger equations. We propose to analyze Complex Absorbing Potentials, Perfectly Matched Layers and Absorbing Boundary Conditions. The time discretization is made by using a semi-implicit relaxation scheme which avoids any fixed point procedure. The spatial discretization involves finite element methods. We propose some numerical experiments to compare the approaches

    Absorbing boundary conditions for the two-dimensional Schrödinger equation with an exterior potential. Part II: Discretization and numerical results

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    International audienceFour families of ABCs where built in [5] for the two- dimensional linear Schr ̈odinger equation with time and space depen- dent potentials and for general smooth convex fictitious surfaces. The aim of this paper is to propose some suitable discretization schemes of these ABCs and to prove some semi-discrete stability results. Fur- thermore, the full numerical discretization of the corresponding initial boundary value problems is considered and simulations are provided to compare the accuracy of the different ABCs

    Absorbing Boundary Conditions for General Nonlinear Schrödinger Equations

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    International audienceThis paper addresses the construction of different families of absorbing boundary conditions for the one- and two-dimensional Schrödinger equation with a general variable nonlinear potential. Various semi-discrete time schemes are built for the associated initial boundary value problems. Finally, some numerical simulations give a comparison of the various absorbing boundary conditions and associated schemes to analyze their accuracy and efficiency

    Circular economy practices and strategies in public sector organizations: An integrative review

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    The concept of the Circular Economy (CE) is an increasingly attractive approach to tackling current sustainability challenges and facilitating a shift away from the linear “take-make-use-dispose” model of production and consumption. The public sector is a major contributor to the CE transition not only as a policy-maker but also as a significant purchaser, consumer, and user of goods and services. The circularization of the public sector itself, however, has received very little attention in CE research. In order to explore the current state of knowledge on the implementation of CE practices and strategies within Public Sector Organizations (PSOs), this research aims to develop an overview of the existing literature. The literature review was designed combining a systematic search with a complementary purposive sampling. Using organizational sustainability as a theoretical perspective, the main results showed a scattered landscape, indicating that the limited research on CE practices and strategies in PSOs has focused so far on the areas of public procurement, internal operations and processes, and public service delivery. As a result of this literature review, an organizational CE framework of a PSO is proposed providing a holistic view of a PSO as a system with organizational dimensions that are relevant for the examination and analysis of the integration process of CE practices and strategies. This innovative framework aims to help further CE research and practice to move beyond current sustainability efforts, highlighting that public procurement, strategy and management, internal processes and operations, assessment and communication, public service delivery, human resources dimensions, collaboration with other organizations, and various external contexts are important public sector areas where the implementation of CE has the potential to bring sustainability benefits

    A survey of Circular Economy initiatives in Portuguese central public sector organisations: National outlook for implementation

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    The Circular Economy (CE) is generally understood as an opportunity to transform the current unsustainable linear economic system by redesigning the way organisations provide goods and services rethinking how society consumes and uses those resources. In this context, the public sector is mainly recognised as an actor enabling the implementation of a sustainable CE through governmental interventions and policy initiatives. However, there is a lack of studies considering the public sector at an organisational level. CE in organisations includes a wide range of different practices that are important to examine in order to analyse the CE implementation process. Consequently, this study aims to characterise the current state of implementing circular practices and supporting strategies in central public sector organisations. To fulfil this aim, a questionnaire survey was sent to the organisations pertaining to the Portuguese Central Public Administration, as surveys are valuable tools to systematically collect information on various topics. The results demonstrate a relatively low level of implementation. Circular practices such as purchasing remanufactured or used items, using sharing platforms, increasing the efficiency of buildings, adopting green human resources and collaborative initiatives for circularity, and assessing and communicating about CE activities have presented low levels of adoption. At the same time, waste collection for recycling and dematerialisation practices showed good implementation levels. There is, thus, immense potential for further implementation of circularity in central public sector organisations in Portugal. This research contributes to deepening the understanding of the extent to which circular practices are embedded in public sector organisations and identifying the main implementation strengths and weaknesses. This research has the potential to help practitioners and researchers in the transition towards circularity in identifying circular opportunities in their organisations and in building a vision to further implement circularity in public sector organisations

    Advancing the Circular Economy in Public Sector Organisations: Employees’ Perspectives on Practices

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    Circular economy (CE) is a concept that is gaining attention as an approach to help accelerate the transition towards sustainability. Research has focused on the adoption of CE practices in the business sector while the adoption within public sector organisations has been relatively overlooked. Examining CE adoption in the public sector through the perceptive of employees is crucial because of their expertise in the organisation where they work. The main aim of this study is to identify what public employees perceive as suitable CE practices for their organisations and their critical role in implementation. As the adoption of CE practices is influenced by social and material configurations, this research has taken a case study approach, focused on the Portuguese Central Public Administration. Semi-structured interviews were conducted with public employees working on CE and sustainability issues, and a complementary analysis was undertaken of governmental reports and legislative documents. The results show that public employees view the existence and potential of CE practices mainly in the area of public procurement but also in resource efficiency and optimisation, dematerialisation and in practices related to the R-hierarchy including reduce and reuse. Both technical-oriented practices aimed to achieve traditional resource efficiency, and human-centred practices targeted at reducing consumption and sharing resources have been identified. This research provides insights into how a specific group of stakeholders envisions CE activities for their sector. Identification of practices for central public sector has the potential to assist decision-makers in the process of defining priorities for CE planning, implementation and monitoring. This study focusing on CE practices in central public sector organisations contributes to the calls for an inclusion of human/socially-based practices centred around consumption reduction, sharing and dematerialisation activities to enhance the transformative and innovative potential of CE

    Notre Professeur

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    On reconnaissait Monsieur Gourbin Ă  sa prestance, son sourire franc et son rire charmant. L’esprit toujours en Ă©bullition, sans doute prĂ©occupĂ© par ses mille fonctions, il m’arrivait de le croiser avant le cours et de lui indiquer la salle de classe (qui changeait quasiment toutes les semaines). Ses cours Ă©taient riches et denses. Il avait le souci de clarifier le plus possible ses idĂ©es, allant parfois jusqu’à dix exemples consĂ©cutifs pour en expliquer une. Il prenait le temps d’analyser les..
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