60 research outputs found

    Revising a Collection Development Manual: Challenges and Opportunities

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    Collection development manuals remain highly relevant to library strategic goals, though they are often in need of revision. Staffing models and strategic goals for liaison librarians and subject specialists are evolving rapidly with collection development competing with information literacy, scholarly communication, and digital services for time and resources. In this context, it is more and more likely for important knowledge about local and general best practices to be forgotten or neglected. At the same time, many new librarians inherit collections responsibility in a market for scholarly content in unstable formats and price models. This paper outlines the experience of Howard-Tilton Memorial Library at Tulane University as it made a series of changes to its manual in 2013

    A Helium-Surface Interaction Potential of Bi2_2Te3_3(111) from Ultrahigh-Resolution Spin-Echo Measurements

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    We have determined an atom-surface interaction potential for the He−-Bi2_2Te3_3(111) system by analysing ultrahigh resolution measurements of selective adsorption resonances. The experimental measurements were obtained using 3^3He spin-echo spectrometry. Following an initial free-particle model analysis, we use elastic close-coupling calculations to obtain a three-dimensional potential. The three-dimensional potential is then further refined based on the experimental data set, giving rise to an optimised potential which fully reproduces the experimental data. Based on this analysis, the He−-Bi2_2Te3_3(111) interaction potential can be described by a corrugated Morse potential with a well depth D=(6.22±0.05) meVD=(6.22\pm0.05)~\mathrm{meV}, a stiffness κ=(0.92±0.01) A˚−1\kappa =(0.92\pm0.01)~\mathrm{\AA}^{-1} and a surface electronic corrugation of (9.6±0.2)(9.6\pm0.2)% of the lattice constant. The improved uncertainties of the atom-surface interaction potential should also enable the use in inelastic close-coupled calculations in order to eventually study the temperature dependence and the line width of selective adsorption resonances

    NaIrO3 - A pentavalent post-perovskite

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    Sodium iridium(V) oxide, NaIrO3, was synthesized by a high pressure solid state method and recovered to ambient conditions. It is found to be isostructural with CaIrO3, the much-studied structural analogue of the high-pressure post-perovskite phase of MgSiO3. Among the oxide post-perovskites, NaIrO3 is the first example with a pentavalent cation. The structure consists of layers of corner- and edge-sharing IrO6 octahedra separated by layers of NaO8 bicapped trigonal prisms. NaIrO3 shows no magnetic ordering and resistivity measurements show non-metallic behavior. The crystal structure, electrical and magnetic properties are discussed and compared to known post-perovskites and pentavalent perovskite metal oxides.Comment: 22 pages, 5 figures. Submitted to Journal of Solid State Chemistr

    Endomicroscopic and transcriptomic analysis of impaired barrier function and malabsorption in environmental enteropathy

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    Introduction: Environmental enteropathy (EE) is associated with growth failure, micronutrient malabsorption and impaired responses to oral vaccines. We set out to define cellular mechanisms of impaired barrier function in EE and explore protective mechanisms. Methods: We studied 49 adults with environmental enteropathy in Lusaka, Zambia using confocal laser endomicroscopy (CLE); histology, immunohistochemistry and mRNA sequencing of small intestinal biopsies; and correlated these with plasma lipopolysaccharide (LPS) and a zinc uptake test. Results: CLE images (median 134 for each study) showed virtually ubiquitous small intestinal damage. Epithelial defects, imaged by histology and claudin 4 immunostaining, were predominantly seen at the tips of villi and corresponded with leakage imaged in vivo by CLE. In multivariate analysis, circulating log-transformed LPS was correlated with cell shedding events (β = 0.83; P = 0.035) and with serum glucagon-like peptide-2 (β = -0.13; P = 0.007). Zinc uptake from a test dose of 25mg was attenuated in 30/47 (64%) individuals and in multivariate analysis was reduced by HIV, but positively correlated with GLP-2 (β = 2.72; P = 0.03). There was a U-shaped relationship between circulating LPS and villus surface area. Transcriptomic analysis identified 23 differentially expressed genes in severe enteropathy, including protective peptides and proteins. Conclusions: Confocal endomicroscopy, claudin 4 immunostaining and histology identify epithelial defects which are probably sites of bacterial translocation, in the presence of which increased epithelial surface area increases the burden of translocation. GLP 2 and other protective peptides may play an important role in mucosal protection in EE

    Anomalous Shubnikov-de Haas quantum oscillations in rare-earth tritelluride

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    Contains fulltext : 228092.pdf (publisher's version ) (Open Access
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