140 research outputs found

    CHAMPION: Chalmers Hierarchical Atomic, Molecular, Polymeric & Ionic Analysis Toolkit

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    We present CHAMPION: a software developed to automatically detect time-dependent bonds between atoms based on their dynamics, classify the local graph topology around them, and analyze the physicochemical properties of these topologies by statistical physics. In stark contrast to methodologies where bonds are detected based on static conditions such as cut-off distances, CHAMPION considers pairs of atoms to be bound only if they move together and act as a bound pair over time. Furthermore, the time-dependent global bond graph is possible to split into dynamically shifting connected components or subgraphs around a certain chemical motif and thereby allow the physicochemical properties of each such topology to be analyzed by statistical physics. Applicable to condensed matter and liquids in general, and electrolytes in particular, this allows both quantitative and qualitative descriptions of local structure, as well as dynamical processes such as speciation and diffusion. We present here a detailed overview of CHAMPION, including its underlying methodology, implementation and capabilities.Comment: 11 pages, 8 figure

    Research strategies for organizational history:a dialogue between historical theory and organization theory

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    If history matters for organization theory, then we need greater reflexivity regarding the epistemological problem of representing the past; otherwise, history might be seen as merely a repository of ready-made data. To facilitate this reflexivity, we set out three epistemological dualisms derived from historical theory to explain the relationship between history and organization theory: (1) in the dualism of explanation, historians are preoccupied with narrative construction, whereas organization theorists subordinate narrative to analysis; (2) in the dualism of evidence, historians use verifiable documentary sources, whereas organization theorists prefer constructed data; and (3) in the dualism of temporality, historians construct their own periodization, whereas organization theorists treat time as constant for chronology. These three dualisms underpin our explication of four alternative research strategies for organizational history: corporate history, consisting of a holistic, objectivist narrative of a corporate entity; analytically structured history, narrating theoretically conceptualized structures and events; serial history, using replicable techniques to analyze repeatable facts; and ethnographic history, reading documentary sources "against the grain." Ultimately, we argue that our epistemological dualisms will enable organization theorists to justify their theoretical stance in relation to a range of strategies in organizational history, including narratives constructed from documentary sources found in organizational archives. Copyright of the Academy of Management, all rights reserved

    Incidence, etiology, and outcomes of pre- and post-operative atrial fibrillation in mitral valve procedures: a review

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    Although pre-procedural and post-procedural atrial fibrillation occur commonly in mitral valve (MV) patients, the impact on patient outcomes and resource utilization has not been well documented. A comprehensive PubMed review was performed using a combination of MeSH terms related to atrial fibrillation, MV disease, MV and atrial fibrillation procedures, and medical management. Additional publications were selected from the reference lists of studies identified in the literature search. This review found that several studies conflict with the short-term outcomes associated with pre- and post-operative atrial fibrillation in MV patients. In general, both pre- and post-operative atrial fibrillation have clear negative long-term impacts on MV patients’ mortality and risk of stroke, major bleeding and other thromboembolic events. Surgical ablation for pre-operative atrial fibrillation and transcatheter ablation for medically resistant post-operative atrial fibrillation appears to be safe and effective procedure; these percutaneous and surgical interventions have been documented to mitigate MV-related thromboembolic risk. For MV patients, evidence suggests that the first step should be to optimize the current medical therapy; for persistent symptoms not addressed medically, ablation procedures should be considered. To optimize MV patients’ quality of care, however, additional research appears warranted to prevent long-term adverse outcomes
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