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Mesh generation of curvilinear polygons for the high-order virtual element method (VEM)
Get PDFWe present a proof-of-concept methodology for generating curvilinear polygonal meshes suitable for high-order discretisations by the Virtual Element Method (VEM). A VEM discretisation requires the definition of a set of boundary and internal points used to define basis functions and compute integrals of polynomials. The procedure to locate these points on the boundary borrows ideas from previous work on a posteriori high-order mesh generation in which the geometrical inquiries to a B-rep model of the computational domain are performed via an interface to CAD libraries. Here we describe the steps of the procedure that transforms a straight-sided polygonal mesh, generated using third-party software, into a curvilinear boundary-conforming mesh. We discuss criteria for ensuring and verifying the validity of the mesh. Using an elliptic partial differential equation with Dirichlet boundary conditions as a model problem, we show that VEM discretisations on such meshes achieve the expected rates of convergence as the mesh resolution is increased. This is followed by an illustrative application of the method to the generation of a curvilinear polygonal mesh for an aerofoil geometry. We discuss polygonal curvilinear mesh quality and its enhancement, and use the motion of a cell vertex to appraise three elemental quality metrics, namely convexity, regularity and isotropy, and highlight some of the difficulties associated in their use for mesh quality optimisation. A derivative-free optimisation method is utilised to enhance curvilinear polygonal meshes by maximising a suitable measure of mesh quality. We propose such measure as a combination of the three quality metrics and apply it to optimise a distorted initial mesh for a ring geometry. We show that a suitable version of the convexity metric is effective in untangling invalid meshes. The VEM solution of a model elliptic equation is obtained for a ring geometry where a distorted and an optimised mesh show low errors, indicating that the VEM is robust and relatively insensitive to mesh distortion, and a reduction of the error in the optimised mesh. Finally, we use a more complex geometry, a computational domain for an aerofoil, as a benchmark to further illustrate the ability of the convexity metric to untangle meshes, and also to assess the suitability of two quality measures as optimisation targets to improve the overall quality of curvilinear polygonal meshes.</p
It's Not Just What You Say, but How You Say It:The Effects of Enterprise Social Media on Service Management, Through the Lens of Signaling Theory
Get PDFFrontline service workers are crucial to service delivery and have been a long-standing focus of research, with scholars and practitioners alike maintaining an interest in their effective management. As technology increasingly transforms this context, the way in which managers in service organizations communicate with frontline workers has also evolved, with a notable increase in the use of enterprise social media (ESM). This study investigates the idea that it is not just ‘what’ management says (service-oriented messaging) but ‘the way’ they say it (via ESM) that matters. Drawing on interviews with 36 informants and guided by signaling theory, this study explores how ESM influences customer-focused signaling via management communication and HR implementation in the frontline service context, fostering conditions for a service climate. Findings reveal that ESM's affordances can potentially enhance service climate by strengthening HR system strength, promoting voice, and fostering informal leadership. However, risks such as manager role ambiguity, perceptions of mixed messaging, and over-surveillance are also identified. This study highlights the double-edged implications of ESM in its shaping of service-oriented signaling and emphasizes the importance of the signaling environment in realizing its benefits while mitigating its risks
Rationale for Targeting Complement to Mitigate Renal Transplant Ischemia-Reperfusion Injury
No full textIschemia-reperfusion injury (IRI) is an unavoidable consequence of kidney transplantation and a major contributor to delayed graft function (DGF). DGF, traditionally defined as the need for dialysis within the first week post-Transplant, is linked to inferior graft and patient outcomes, prolonged hospitalization, and higher health care costs. IRI begins with tissue hypoxia, which triggers an inflammatory response upon reperfusion. The renal tubule plays a critical role in complement synthesis, with local activation driving inflammation and graft immunogenicity more than circulating liver-derived complement. The lectin pathway is a key initiator of complement activation in hypoxic renal tubules, primarily through collectin-11's interaction with glycan ligands on hypoxic cells, with further amplification via the alternative pathway. Despite promising preclinical results, systemic complement inhibitors have not significantly improved DGF in clinical studies, likely due to inefficient targeting of ischemic renal tubules. Machine perfusion offers a novel approach to delivering therapeutics directly to donor kidneys. Notably, hypothermic machine perfusion has improved DGF rates and early graft outcomes. Emerging targeted delivery systems using extracellular vesicles or nanoparticle-based carriers also promise to deliver therapeutics to the sites of injury. Organ-Targeted complement inhibition via machine perfusion or other targeted delivery systems represent compelling strategies for IRI prevention. Finally, multigenic xenografts engineered to prevent complement activation have shown initial promise in overcoming the complement-mediated barriers that continue to challenge allotransplantation in humans.</p
Optimizing treatment allocation in the presence of interference
No full textIn Influence Maximization (IM), the objective is to — given a budget — select the optimal set of entities in a network to target with a treatment so as to maximize the total effect. For instance, in marketing, the objective is to target the set of customers that maximizes the total response rate, resulting from both direct treatment effects on targeted customers and indirect, spillover, effects that follow from targeting these customers. Recently, new methods to estimate treatment effects in the presence of network interference have been proposed. However, the issue of how to leverage these models to make better treatment allocation decisions has been largely overlooked. Traditionally, in Uplift Modeling (UM), entities are ranked according to estimated treatment effect, and the top entities are allocated treatment. Since, in a network context, entities influence each other, the UM ranking approach will be suboptimal. The problem of finding the optimal treatment allocation in a network setting is NP-hard, and generally has to be solved heuristically. To fill the gap between IM and UM, we propose OTAPI: Optimizing Treatment Allocation in the Presence of Interference to find solutions to the IM problem using treatment effect estimates. OTAPI consists of two steps. First, a causal estimator is trained to predict treatment effects in a network setting. Second, this estimator is leveraged to identify an optimal treatment allocation by integrating it into classic IM algorithms. We demonstrate that this novel method outperforms classic IM and UM approaches on both synthetic and semi-synthetic datasets.</p
Gathering autistic adults’ visual experiences to inform adaptations:a qualitative interview study
Get PDFSensory processing difficulties are highly prevalent in autism and affect quality of life. Identifying the lived visual experiences of autistic individuals across the lifespan is important for informing interventions, adaptations, and mechanistic understanding of differences in visual perception. However limited research exists exploring the visual experiences of autistic adults. To address this knowledge gap, semi-structured interviews were conducted with 20 autistic adults, and data were analysed using framework analysis. Six main themes emerged: hypersensitivity, detail focus, face processing, social and emotional impact, everyday impact of visual experiences, and preferred visual environment and adaptations. This study provides further insight into the visual sensory experiences of autistic adults and the marked impact of these experiences on physical, social, and emotional well-being. The importance of consulting autistic individuals in the design of work and community spaces is highlighted in addition to improved awareness of sensory issues and greater understanding from the wider community
‘Being Real’ and ‘Being Boundaried’:A Qualitative Study of Practitioners' Provision of Authentic Care in a Service for Young Care Leavers
Get PDFThis study explores experiences of authentic care among practitioners and young people at The House Project, an organization supporting young people leaving care in the United Kingdom. We conducted observations, interviews and focus groups with a total of 41 practitioners and 37 young people in multiple local projects over the course of 2 years. The study offers three main findings. First, practitioners and young people place significant value on relationships of authentic care and perceive these as characterized by mutual self-disclosure, genuine emotional investment and practitioners' willingness to ‘go above and beyond’ in their work. Second, the provision of authentic care in a professional setting is subject to several challenges for practitioners: managing the heightened emotional impact of caring authentically for young people, maintaining balance and boundaries between work and home lives and navigating career transitions. Third, practitioners responded to these challenges through what we call ‘flexible boundary setting’ and by cultivating networks of support. Further research is needed to determine how to best support staff in the provision of authentic care.</p
Francis Bacon: Decadent?
No full textFrancis Bacon: decadent? A provocative question. An important one, too, I argue: one that sheds new light on Bacon’s relationship to form, to pessimism and to existentialism
