559 research outputs found

    Bernoulli Potential, Hall Constant and Cooper Pairs Effective Masses in Disordered BCS Superconductors

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    It is analyzed what fundamental new information for the properties of the superconductors can be obtained by systematic investigation of the Bernoulli effect. It is shown that it is a tool to determine the effective mass of Cooper pairs, the volume density of charge carriers, the temperature dependence of the penetration depth and condensation energy. The theoretical results for disordered and anisotropic gap superconductors are systematized for this aim. For clean-anisotropic-gap superconductors is presented a simple derivation for the temperature dependence of the penetration depthComment: 13 pages, 3 figures, LaTeX 2e, New figure and reference

    Description of the Larva of Athous monilicornis (Coleoptera, Elateridae), with Notes on the Species Distribution

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    First description of the larva of Athous (Haplathous) monilicornis Schwarz, 1897, a species endemic to the Balkan Peninsula, known so far from Bulgaria, and reported in this paper from Macedonia and Greece as well. The larva differs from the other representative of subgenus Haplathous occurring in the high mountains of Bulgaria Athous subfuscus (Muller), by the width of the pit of the urogomphi. Athous monilicornis is confined to the subalpine habitats and the upper coniferous forests belt of the mountains of Bulgaria, Macedonia and Greece.Впервые описана личинка щелкуна Athous (Haplathous) monilicornis Schwarz, 1897, вида, эндемичного для Балканского п-ова и известного из Болгарии, а также Греции и Македонии. От личинок встречающегося в высокогорьях Болгарии Athous (Haplathous) subfuscus (Muller) отличается шириной ямки на урогомфах. Распространение A. monilicornis в горах Болгарии, Македонии и Греции ограничено субальпикой и верхней частью пояса хвойного леса

    PhytoKeys at 100: progress in sustainability, innovation, and speed to enhance publication in plant systematics

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    The file attached is the Published/publisher’s pdf version of the article.This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.NHM Repositor

    Influence of the van Hove singularity on the specific heat jump in BCS superconductors

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    Within the weak-coupling BCS scheme we derive a general form of the coefficients in the Ginzburg-Landau expansion of the free energy of a superconductor for the case of a Fermi level close to a van Hove singularity (VHS). A simple expression for the influence of the VHS on the specific heat jump is then obtained for the case where gaps for different bands are distinct but nearly constant at the corresponding sheets of the Fermi surface.Comment: 8 pages, 2 figures, LaTeX2

    Document mark-up for different users and purposes

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    Semantic enhancement of texts aids their use by researchers. However, mark-up of large bodies of text is slow and requires precious expert resources. The task could be automated if there were marked-up texts to train and test mark-up tools. This paper looks at the re-purposing of texts originally marked-up to support taxonomists to provide computer scientists with training and test data for their mark-up tools. The re-purposing highlighted some key differences in the requirements of taxonomists and computer scientists and their approaches to mark-up

    The 3d-to-4s-by-2p highway to superconductivity in cuprates

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    High-temperature superconductors are nowadays found in great variety and hold technological promise. It is still an unsolved mystery that the critical temperature T_c of the basic cuprates is so high. The answer might well be hidden in a conventional corner of theoretical physics, overlooked in the recent hunt for exotic explanations of new effects in these materials. A forgotten intra-atomic s-d two-electron exchange in the Cu atom is found to provide a strong (~eV) electron pairing interaction. A Bardeen-Cooper-Schrieffer approach can explain the main experimental observations and predict the correct d_{x^2-y^2} symmetry of the gap.Comment: 4 pages, 3 figures, LaTeX2

    Community next steps for making globally unique identifiers work for biocollections data

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    Biodiversity data is being digitized and made available online at a rapidly increasing rate but current practices typically do not preserve linkages between these data, which impedes interoperation, provenance tracking, and assembly of larger datasets. For data associated with biocollections, the biodiversity community has long recognized that an essential part of establishing and preserving linkages is to apply globally unique identifiers at the point when data are generated in the field and to persist these identifiers downstream, but this is seldom implemented in practice. There has neither been coalescence towards one single identifier solution (as in some other domains), nor even a set of recommended best practices and standards to support multiple identifier schemes sharing consistent responses. In order to further progress towards a broader community consensus, a group of biocollections and informatics experts assembled in Stockholm in October 2014 to discuss community next steps to overcome current roadblocks. The workshop participants divided into four groups focusing on: identifier practice in current field biocollections; identifier application for legacy biocollections; identifiers as applied to biodiversity data records as they are published and made available in semantically marked-up publications; and cross-cutting identifier solutions that bridge across these domains. The main outcome was consensus on key issues, including recognition of differences between legacy and new biocollections processes, the need for identifier metadata profiles that can report information on identifier persistence missions, and the unambiguous indication of the type of object associated with the identifier. Current identifier characteristics are also summarized, and an overview of available schemes and practices is provided

    The data paper: a mechanism to incentivize data publishing in biodiversity science

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    <p/> <p>Background</p> <p>Free and open access to primary biodiversity data is essential for informed decision-making to achieve conservation of biodiversity and sustainable development. However, primary biodiversity data are neither easily accessible nor discoverable. Among several impediments, one is a lack of incentives to data publishers for publishing of their data resources. One such mechanism currently lacking is recognition through conventional scholarly publication of enriched metadata, which should ensure rapid discovery of 'fit-for-use' biodiversity data resources.</p> <p>Discussion</p> <p>We review the state of the art of data discovery options and the mechanisms in place for incentivizing data publishers efforts towards easy, efficient and enhanced publishing, dissemination, sharing and re-use of biodiversity data. We propose the establishment of the 'biodiversity data paper' as one possible mechanism to offer scholarly recognition for efforts and investment by data publishers in authoring rich metadata and publishing them as citable academic papers. While detailing the benefits to data publishers, we describe the objectives, work flow and outcomes of the pilot project commissioned by the Global Biodiversity Information Facility in collaboration with scholarly publishers and pioneered by Pensoft Publishers through its journals <it>Zookeys</it>, <it>PhytoKeys</it>, <it>MycoKeys</it>, <it>BioRisk</it>, <it>NeoBiota</it>, <it>Nature Conservation</it> and the forthcoming <it>Biodiversity Data Journal</it>. We then debate further enhancements of the data paper beyond the pilot project and attempt to forecast the future uptake of data papers as an incentivization mechanism by the stakeholder communities.</p> <p>Conclusions</p> <p>We believe that in addition to recognition for those involved in the data publishing enterprise, data papers will also expedite publishing of fit-for-use biodiversity data resources. However, uptake and establishment of the data paper as a potential mechanism of scholarly recognition requires a high degree of commitment and investment by the cross-sectional stakeholder communities.</p

    The search for common anthropogenic impacts on biodiversity : a global network

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    We introduce an initiative to assess and compare landscape changes related to human activities on a global scale, using a single group of invertebrates. The GLOBENET programme uses common field methodology (pitfall trapping), to appraise assemblages of ground beetles (Coleoptera, Carabidae) in visually-similar land-mosaics (urban-rural gradients). Carabids were selected as the focal taxon as they are sufficiently varied (both taxonomically and ecologically), abundant and sensitive to the environment. However, work on other taxa is comparable with the GLOBENET framework. The continuum of decreasing human pressure from city centres into the surrounding countryside was selected to represent human-caused disturbance for this initial stage of GLOBENET because these gradients can be found virtually all over the world. Through the broad-scale assessment envisioned in the GLOBENET programme, we seek to separate general, repeated effects on biodiversity from those that depend on local environments or particular biotic assemblages. Based on this understanding we aim to develop simple tools and protocols for assessing ecological effects of human-caused landscape changes, which could help to sustainably manage landscapes for biodiversity and for human requirements. For instance, the response of different functional groups of carabids to these landscape changes may help guide management practices. Further GLOBENET developments and information are available at our website: http://www.helsinki.fi/science/globenet
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