6,539 research outputs found

    Engaging the World Christian Communities in Contemporary Global Societies

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    The chapters in this volume represent the lived experiences of Christians in diverse communities across the globe. It reinforces that Christian communities do not live in a vacuum but in complex, diverse social contexts. A Christian community in this context means a community which is primarily formed by its belief and adherence to Christian faith.https://scholar.csl.edu/edinburghcentenary/1004/thumbnail.jp

    Complex Lagrangian embeddings of moduli spaces of vector bundles

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    By means of a Fourier-Mukai transform we embed moduli spaces of stable bundles on an algebraic curve C as isotropic subvarieties of moduli spaces of mu-stable bundles on the Jacobian variety J(C). When g(C)=2 this provides new examples of special Lagrangian submanifolds.Comment: 9 pages, no figures, to appear in Diff. Geom. App

    Engaging the World Christian Communities in Contemporary Global Societies

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    The chapters in this volume represent the lived experiences of Christians in diverse communities across the globe. It reinforces that Christian communities do not live in a vacuum but in complex, diverse social contexts. A Christian community in this context means a community which is primarily formed by its belief and adherence to Christian faith.https://scholar.csl.edu/edinburghcentenary/1004/thumbnail.jp

    An elusive ghost: searching for the Eagle Owl (Bubo bubo) in the past of Britain

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    The Eagle Owl (Bubo bubo) is currently absent as a regular breeder in Britain and its status as a native species has been debated. Its occurrence in the Pleistocene of Britain is sparse but uncontroversial, whereas its Holocene presence rests on very few ambiguous findings. Of these, a specimen from Demen's Dale (Derbyshire) originally attributed to the Mesolithic period is the most important. A re-evaluation of this bone (tarsometatarsus) is presented in this paper. Although its identification as an Eagle Owl is confirmed, radiocarbon dating suggests that the bird rather lived in the Late Pleistocene. On the basis of the current evidence, there are no Holocene remains of the Eagle Owl in the archaeological and fossil record of Britain and the native status of this species remains unconfirmed

    Structural and chemical embrittlement of grain boundaries by impurities: a general theory and first principles calculations for copper

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    First principles calculations of the Sigma 5 (310)[001] symmetric tilt grain boundary in Cu with Bi, Na, and Ag substitutional impurities provide evidence that in the phenomenon of Bi embrittlement of Cu grain boundaries electronic effects do not play a major role; on the contrary, the embrittlement is mostly a structural or "size" effect. Na is predicted to be nearly as good an embrittler as Bi, whereas Ag does not embrittle the boundary in agreement with experiment. While we reject the prevailing view that "electronic" effects (i.e., charge transfer) are responsible for embrittlement, we do not exclude the role of chemistry. However numerical results show a striking equivalence between the alkali metal Na and the semi metal Bi, small differences being accounted for by their contrasting "size" and "softness" (defined here). In order to separate structural and chemical effects unambiguously if not uniquely, we model the embrittlement process by taking the system of grain boundary and free surfaces through a sequence of precisely defined gedanken processes; each of these representing a putative mechanism. We thereby identify three mechanisms of embrittlement by substitutional impurities, two of which survive in the case of embrittlement or cohesion enhancement by interstitials. Two of the three are purely structural and the third contains both structural and chemical elements that by their very nature cannot be further unravelled. We are able to take the systems we study through each of these stages by explicit computer simulations and assess the contribution of each to the nett reduction in intergranular cohesion. The conclusion we reach is that embrittlement by both Bi and Na is almost exclusively structural in origin; that is, the embrittlement is a size effect.Comment: 13 pages, 5 figures; Accepted in Phys. Rev.

    Development and management of systemic lupus erythematosus in an HIV-infected man with hepatitis C and B co-infection following interferon therapy: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The association of human immunodeficiency virus and immune dysfunction leading to development of autoimmune markers is well described, but human immunodeficiency virus infection is relatively protective for the development of systemic lupus erythematosus. In contrast, development of systemic lupus erythematosus with hepatitis C and with interferon therapy is well described in a number of case reports. We here describe the first case of systemic lupus erythematosus developing in a man infected with human immunodeficiency virus, hepatitis C and hepatitis B co-infection where the onset seems to have been temporally related to interferon therapy.</p> <p>Case presentation</p> <p>We report the occurrence of systemic lupus erythematosus complicating interferon-Îą therapy for hepatitis C in a 47-year-old asplenic male with haemophilia co-infected with human immunodeficiency virus and hepatitis B. He presented with a truncal rash, abdominal pains and headache and later developed grade IV lupus nephritis requiring haemodialysis, mycophenolate mofetil and steroid therapy. We were able to successfully withdraw dialysis and mycophenolate while maintaining stable renal function.</p> <p>Conclusion</p> <p>Interferon-Îą is critical in antiviral immunity against hepatitis C but also acts as a pathogenic mediator for systemic lupus erythematosus, a condition associated with activation of plasmacytoid dendritic cells that are depleted in human immunodeficiency virus infection. The occurrence of auto-antibodies and lupus-like features in the coinfections with hepatitis C require careful assessment. Immunosuppressant therapy for lupus risks exacerbating underlying infections in patients with concurrent human immunodeficiency virus, hepatitis B and C.</p

    The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics

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    We present the discovery of the first L-type subdwarf, 2MASS J05325346+8246465. This object exhibits enhanced collision-induced H2_2 absorption, resulting in blue NIR colors (J−Ks=0.26±0.16J-K_s = 0.26{\pm}0.16). In addition, strong hydride bands in the red optical and NIR, weak TiO absorption, and an optical/J-band spectral morphology similar to the L7 DENIS 0205−-1159AB imply a cool, metal-deficient atmosphere. We find that 2MASS 0532+8246 has both a high proper motion, μ\mu = 2\farcs60\pm0\farcs15 yr−1^{-1}, and a substantial radial velocity, vrad=−195±11v_{rad} = -195{\pm}11 km s−1^{-1}, and its probable proximity to the Sun (d = 10--30 pc) is consistent with halo membership. Comparison to subsolar-metallicity evolutionary models strongly suggests that 2MASS 0532+8246 is substellar, with a mass of 0.077 ≲\lesssim M ≲\lesssim 0.085 M_{\sun} for ages 10--15 Gyr and metallicities Z=0.1−0.01Z = 0.1-0.01 Z_{\sun}. The discovery of this object clearly indicates that star formation occurred below the Hydrogen burning mass limit at early times, consistent with prior results indicating a flat or slightly rising mass function for the lowest-mass stellar subdwarfs. Furthermore, 2MASS 0532+8246 serves as a prototype for a new spectral class of subdwarfs, additional examples of which could be found in NIR proper motion surveys.Comment: 9 pages, 3 figures, accepted to Ap

    A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR

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    Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-C-13(2)-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (similar to 120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40A degrees, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed

    Super Calabi-Yau's and Special Lagrangians

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    We apply mirror symmetry to the super Calabi-Yau manifold CP^{(n|n+1)} and show that the mirror can be recast in a form which depends only on the superdimension and which is reminiscent of a generalized conifold. We discuss its geometrical properties in comparison to the familiar conifold geometry. In the second part of the paper examples of special-Lagrangian submanifolds are constructed for a class of super Calabi-Yau's. We finally comment on their infinitesimal deformations.Comment: 20 pages, no figures, latex; v2: references added; v3: minor clarifications added, version published in JHE
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