744,509 research outputs found

    Reconciling structure and agency in strategy -as-practice research: Towards a strong- structuration theory approach

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    An overwhelming focus of research on the micro agency of strategic actors has led to the literature being characterized as demonstrating a micro-myopia, resulting in a micro-isolationism. This means we know little about how the micro interrelates with the macro in strategy work. We address this problem in our conceptual article which adopts a structurationist stance to explicate how strategy-as-practice (SaP) research could be enhanced and extended by paying equal attention to both agency and structure. Specifically, we advance strong structuration theory (SST), a promising development from Giddens’ seminal work on structuration theory, to show how strategic activity can be understood as an ongoing process of structuration unfolding over time. We argue for the use of both types of methodological bracketing (context and conduct analysis), advocating systematic attention to the interplay between macro-societal and micro-local levels of analysis. Our discussion concludes with guidance for researchers inviting them to undertake empirical fieldwork that overcomes SaP’s current micro-myopia, creating a more balanced corpus of work

    Do interactions between plant roots and the rhizosphere affect parasitoid behaviour?

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    Multitrophic interactions are powerful forces shaping the structure of living communities. Plants encounter a great diversity of organisms in their environment: some of these interactions are beneficial (e.g. symbiotic fungi and insect pollinators) while some are detrimental (e.g. herbivorous insects and pathogenic micro-organisms). Multitrophic interactions between below-ground and above-ground organisms are receiving increasing attention because they may influence plant defences against biotic and abiotic stresses. In this study we show that an arbuscular mycorrhizal symbiosis makes tomato plants significantly more resistant towards aphids, by enhancing both direct defences, both attractivity towards aphid parasitoids

    Rethinking Trust, Crime Policy and Social Theory,

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    This article analyses the relationship of ‘trust’ to crime, power and criminal justice policy. The theoretical model employed to analyse this relationship draws from Owen’s (2009a), conceptually driven argument that is based on an ontologically-flexible critique of agency-structure, micro-macro and time-space. This relationship stands at the interface of competing pressures working to produce the increasing complexity of crime and criminal justice policy (Powell 2005). We then move the attention to the conceptual problems of ‘trust’ which is linked with uncertainty and complexity whilst law and order and crime policies rest on the specialist knowledge claimed by a range of professional “experts” and technologists that inhabit powerful spaces through which crime policy and practice is governed and articulated

    A critical analysis of multilingual dictionaries

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    This article evaluates the lexicographic value of multilingual dictionaries. Dictionaries covering three or more languages spoken in South Africa are taken as a case in point. An attempt will be made to reflect on their merits and shortcomings as reference works and learning tools but the focus will be on presumed shortcomings in the macro and micro structures of such dictionaries with special attention to the lemmatisation of common words, quality of the dictionary articles and consistency in presentation.Keywords: Multilingual dictionaries, Macro structure, Micro structure, African languages, Thematic ordering, Alphabetic orderin

    Fearless Luminance Adaptation: A Macro-Micro-Hierarchical Transformer for Exposure Correction

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    Photographs taken with less-than-ideal exposure settings often display poor visual quality. Since the correction procedures vary significantly, it is difficult for a single neural network to handle all exposure problems. Moreover, the inherent limitations of convolutions, hinder the models ability to restore faithful color or details on extremely over-/under- exposed regions. To overcome these limitations, we propose a Macro-Micro-Hierarchical transformer, which consists of a macro attention to capture long-range dependencies, a micro attention to extract local features, and a hierarchical structure for coarse-to-fine correction. In specific, the complementary macro-micro attention designs enhance locality while allowing global interactions. The hierarchical structure enables the network to correct exposure errors of different scales layer by layer. Furthermore, we propose a contrast constraint and couple it seamlessly in the loss function, where the corrected image is pulled towards the positive sample and pushed away from the dynamically generated negative samples. Thus the remaining color distortion and loss of detail can be removed. We also extend our method as an image enhancer for low-light face recognition and low-light semantic segmentation. Experiments demonstrate that our approach obtains more attractive results than state-of-the-art methods quantitatively and qualitatively.Comment: Accepted by ACM MM 202

    Optimization of the design of ducted-fan hovering micro air vehicles using finite element simulation and orthogonal design

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    The structural design and flight stability characteristics of micro air vehicles have received much attention due to its low Reynolds number. Compared with fixed-wing aircraft, hovering ducted-fan micro air vehicles with vertical takeoff and landing and hovering capabilities have promising prospect. In this article, a flexible membrane and inflatable structure has been used as the aerodynamic shape of an aircraft model. Its advantages have been analyzed and verified by fluid-structure interaction based on finite element method. The flight stability of hovering micro air vehicles has also been investigated based on the theory of motion of structure. In order to improve the flight stability of the designed hovering micro air vehicle model, the effects of geometrical parameters and materials have been analyzed through an orthogonal experimental design. Based on the optimized results, the aircraft prototype has been manufactured for experimental test. The elastic deformation produced on its flexible membrane structure is obtained by stroboscopic stereo imaging method and a purpose-built experimental environment. The numerical simulation results indicated that the thickness of membrane and material of vertical duct have significant effects on the micro air vehicle flight stability and disturbance resistance ability. The results have confirmed that the flexible aerodynamic mechanisms produced by the aeroelastic deformation of spherical membrane can enhance the micro air vehicle stability.This work was financially supported by Support Program of National Ministry of Education of China (No. 625010110), National Natural Science Foundation of China (No. 61179043), and Specialized Research Fund for the Doctoral Program (SRFDP) of Higher Education (No. 20070056085)

    Isotropic Band Gaps and Freeform Waveguides Observed in Hyperuniform Disordered Photonic Solids

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    Recently, disordered photonic media and random textured surfaces have attracted increasing attention as strong light diffusers with broadband and wide-angle properties. We report the first experimental realization of an isotropic complete photonic band gap (PBG) in a two-dimensional (2D) disordered dielectric structure. This structure is designed by a constrained-optimization method, which combines advantages of both isotropy due to disorder and controlled scattering properties due to low density fluctuations (hyperuniformity) and uniform local topology. Our experiments use a modular design composed of Al2O3 walls and cylinders arranged in a hyperuniform disordered network. We observe a complete PBG in the microwave region, in good agreement with theoretical simulations, and show that the intrinsic isotropy of this novel class of PBG materials enables remarkable design freedom, including the realization of waveguides with arbitrary bending angles impossible in photonic crystals. This first experimental verification of a complete PBG and realization of functional defects in this new class of materials demonstrates their potential as building blocks for precise manipulation of photons in planar optical micro-circuits and has implications for disordered acoustic and electronic bandgap materials
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