41,479 research outputs found

    Species richness and beta-diversity of aquatic macrophytes assemblages in three floodplain tropical lagoons: evaluating the effects of sampling size and depth gradients

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    Using aquatic macrophyte data gathered in three lagoons of the ParanĂĄ River floodplain we showed a strong effect of sample size on species richness. Incidence-based species richness estimators (Chao 2, jackknife 1, jackknife 2, incidence-based coverage estimator and bootstrap) were compared to evaluate their performance in estimating the species richness throughout transect sampling rnethod. Our results suggest that the best estimate of the species richness was gave by jackknife 2 estimator. Nevertheless, the transect sampling design was considered inappropriate to estimate aquatic macrophytes species richness. Depth gradient was not a good predictor of the species richness and species turnover (beta diversity). The dynamics of these environments, subject to high water-level fluctuation prevents the formation and permanence of a clear floristic depth-related gradient

    Restrictions over two-dimensional gauge models with Thirring-like interaction

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    Some years ago, it was shown how fermion self-interacting terms of the Thirring-type impact the usual structure of massless two-dimensional gauge theories [1]. In that work only the cases of pure vector and pure chiral gauge couplings have been considered and the corresponding Thirring term was also pure vector and pure chiral respectively, such that the vector (or chiral) Schwinger model should not lose its chirality structure due to the addition of the quartic interaction term. Here we extend this analysis to a generalized vector and axial coupling both for the gauge interaction and the quartic fermionic interactions. The idea is to perform quantization without losing the original structure of the gauge coupling. In order to do that we make use of an arbitrariness in the definition of the Thirring-like interaction.Comment: 9 pages, no figure

    Comment on "Weyl fermions and the anomalous Hall effect in metallic ferromagnets"

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    We point out that, contrary to an assertion by Chen, Bergman and Burkov [Phys. Rev. B 88, 125110 (2013)], the non-quantized part of the intrinsic anomalous Hall conductivity can indeed be expressed as a Fermi-surface property even when Weyl points are present in the bandstructure.Comment: Submitted to Physical Review

    Intersectionality, Resistance, and History-Making: A Conversation Between Carolyn D'Cruz, Ruth DeSouza, Samia Khatun, and Crystal McKinnon, Facilitated by Jordana Silverstein

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    A good, solid, history-writing practice is one which, I think, shakes people's ideas of the world and their place in it, compelling them to imagine new social, cultural and political formations which can provide an account of life. Kimberle Crenshaw's development of the term 'intersectionality', and the ways it has been taken up by people of colour within the academy internationally, as well as by activists, provides one example of such imaginative work. Because when you spend some time in the Australian History academic scene, at conferences, in departments, talking to other academics, it's quickly noticeable that one of its key features is its hegemonic whiteness. Even in those spaces that aspire to avoid whiteness, it's inescapable, visible daily, as well as in the themes at conferences, the keynote speakers chosen, the food served, the knowledge shared. When it came time for the Australian Women's History Network conference in 2016, which carried the theme of 'Intersections in History', it felt like this could provide a way of modelling a different kind of Australian academic History space. What would a conversation look like that skipped over the presence of white Anglo Australians, I wondered? What if we just left them to the side? What if we gathered together some of the smartest, sharpest thinkers in Melbourne academia, and spoke amongst ourselves, coming up with new formations of knowledge? And so we did: Crystal, Samia, Ruth and Carolyn gathered together, I asked them some questions, and we had a conversation that, in numerous ways, challenged white hegemonies. We've recreated some of that conversation below, as a way of continuing to think together, and to find new ways of making this thinking public

    Using geographical information systems for management of back-pain data

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2002 MCB UP LtdIn the medical world, statistical visualisation has largely been confined to the realm of relatively simple geographical applications. This remains the case, even though hospitals have been collecting spatial data relating to patients. In particular, hospitals have a wealth of back pain information, which includes pain drawings, usually detailing the spatial distribution and type of pain suffered by back-pain patients. Proposes several technological solutions, which permit data within back-pain datasets to be digitally linked to the pain drawings in order to provide methods of computer-based data management and analysis. In particular, proposes the use of geographical information systems (GIS), up till now a tool used mainly in the geographic and cartographic domains, to provide novel and powerful ways of visualising and managing back-pain data. A comparative evaluation of the proposed solutions shows that, although adding complexity and cost, the GIS-based solution is the one most appropriate for visualisation and analysis of back-pain datasets

    Medical education on fitness to drive : a survey of all UK medical schools

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    Aim: To identify the extent to which medical aspects of fitness to drive (FTD) are taught within UK medical schools. Methods: A survey of all 32 UK medical schools. In-depth interviews with a range of staff at two medical schools; telephone survey of 30 schools. Results: Two thirds of schools reported specific teaching on medical aspects of FTD but few covered it in any depth or in relation to specific medical conditions. Only one school taught FTD in relation to elderly medicine. FTD was an examination topic at only 12 schools. Conclusion: Teaching on FTD is inconsistent across UK medical schools. Many new doctors will graduate with limited knowledge of medical aspects of FTD

    Finding the right answer: an information retrieval approach supporting knowledge sharing

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    Knowledge Management can be defined as the effective strategies to get the right piece of knowledge to the right person in the right time. Having the main purpose of providing users with information items of their interest, recommender systems seem to be quite valuable for organizational knowledge management environments. Here we present KARe (Knowledgeable Agent for Recommendations), a multiagent recommender system that supports users sharing knowledge in a peer-to-peer environment. Central to this work is the assumption that social interaction is essential for the creation and dissemination of new knowledge. Supporting social interaction, KARe allows users to share knowledge through questions and answers. This paper describes KARe�s agent-oriented architecture and presents its recommendation algorithm
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