1,922 research outputs found

    Open Source or Off-the-Shelf?:Establishing an institutional repository for a small institution

    Get PDF
    Effective management of digital assets as well as increasing research exposure and impact are particular challenges faced by smaller institutions with limited infrastructure and resources. The paper explores the significant factors involved in considering, planning and establishing an institutional repository for Bond University, one of the smaller higher education providers in Australia. The salient benefits and advantages as well as the disadvantages of implementing an off-the-shelf product as opposed to an open source solution for an institutional repository are compared. The rationale for choosing a proprietary product over an open source solution is discussed, as well as the process for obtaining funding and the support of key stakeholders within the University. The paper describes the strategies employed to populate the repository retrospectively and to train academic staff and researchers in self-archiving. The development of policy governing the repository and intellectual property and copyright implications are also covered. Background on Bond Universit

    Transforming the library for the new millennium

    Get PDF

    One-pot multi-reaction processes: synthesis of natural products and drug-like scaffolds

    Get PDF
    One-pot multi-reaction processes involving Overman rearrangements, metathesis cyclizations, and Diels–Alder reactions have been developed for the rapid and efficient synthesis of amino-substituted carbocyclic and heterocyclic compounds. This account describes the development and optimization of these processes, as well as their applications in the synthesis of natural products and drug-like scaffolds

    Helium and Nitrogen Enrichment in Massive Main Sequence Stars: Mechanisms and Implications for the Origin of WNL Stars

    Get PDF
    The evolutionary paths taken by massive stars with M60MM \gtrsim 60 \, \mathrm{M}_\odot remain substantially uncertain. They begin their lives as main sequence (MS) O-stars. Depending on their masses, rotation rates, and metallicities, they can then encounter a wide range of evolutionary states with an equally broad set of possible surface compositions and spectral classifications. We present a new grid of calculations for the evolution of such stars that covers a broad range in mass, M/M=60_\odot = 60 to 150150, rotation rate, v/vcrit=0v \, / \, v_{\rm crit} = 0 to 0.60.6, metallicity, [Fe/H]=4[\mathrm{Fe}/\mathrm{H}] = -4 to 00, and α\alpha-element enhancement, [α/Fe]=0[\alpha/\mathrm{Fe}] = 0 to 0.40.4. We show that rotating stars undergo rotationally-induced dredge-up of nucleosynthetic products, mostly He and N, to their surfaces while still on the MS. Non-rotating metal-rich stars also reveal the products of nucleosynthesis on their surfaces because even modest amounts of mass loss expose their "fossil" convective cores: regions that are no longer convective, but which were part of the convective core at an early stage in the star's evolution. Thus surface enhancement of He and N is expected for rotating stars at all metallicities, and for non-rotating stars if they are relatively metal-rich. We calculate a stellar atmosphere for a representative model from our grid, properly accounting for He- and N-enhancement, and show that the resulting spectrum provides a good match to observed WNL stars, strongly suggesting that the physical mechanisms we have identified are the ultimate cause of the WNL phase.Comment: 21 pages, 18 figures, 2 tables, accepted for publication in MNRAS, in pres

    On the origin of nitrogen at low metallicity

    Full text link
    Understanding the evolution of the N/O ratio in the interstellar medium (ISM) of galaxies is essential if we are to complete our picture of the chemical evolution of galaxies at high redshift, since most observational calibrations of O/H implicitly depend upon the intrinsic N/O ratio. The observed N/O ratio, however, shows large scatter at low O/H, and is strongly dependent on galactic environment. We show that several heretofore unexplained features of the N/O distribution at low O/H can be explained by the N seen in metal-poor galaxies being mostly primary nitrogen that is returned to the ISM via pre-supernova winds from rapidly rotating massive stars (M10M \gtrsim 10 M_\odot, v/vcrit0.4v/v_{\rm crit} \gtrsim 0.4). This mechanism naturally produces the observed N/O plateau at low O/H. We show that the large scatter in N/O at low O/H also arises naturally from variations in star-formation efficiency. By contrast, models in which the N and O come primarily from supernovae provide a very poor fit to the observed abundance distribution. We propose that the peculiar abundance patterns we observe at low O/H are a signature that dwarf galaxies retain little of their SN ejecta, leaving them with abundance patterns typical of winds.Comment: 19 pages, 14 figures, 4 tables, accepted for publication in MNRA

    Bulk evidence for single-gap s-wave superconductivity in the intercalated graphite superconductor C6_6Yb

    Get PDF
    We report measurements of the in-plane electrical resistivity ρ\rho and the thermal conductivity κ\kappa of the intercalated graphite superconductor C6_6Yb to temperatures as low as TcT_c/100. When a field is applied along the c-axis, the residual electronic linear term κ0/T\kappa_0/T evolves in an exponential manner for Hc1<H<Hc2H_{c1} < H < H_{c2}. This activated behaviour establishes the order parameter as unambiguously s-wave, and rules out the possibility of multi-gap or unconventional superconductivity in this system.Comment: 4 pages, 4 figs, submitted to Phys. Rev. Let

    The Effects of Fish Trap Mesh Size on Reef Fish Catch off Southeastern Florida

    Get PDF
    Catch and mesh selectivity of wire-meshed fish traps were tested for eleven different mesh sizes ranging from 13 X 13 mm (0.5 x 0.5") to 76 x 152 mm (3 X 6"). A total of 1,810 fish (757 kg) representing 85 species and 28 families were captured during 330 trap hauls off southeastern Florida from December 1986 to July 1988. Mesh size significantly affected catches. The 1.5" hexagonal mesh caught the most fish by number, weight, and value. Catches tended to decline as meshes got smaller or larger. Individual fish size increased with larger meshes. Laboratory mesh retention experiments showed relationships between mesh shape and size and individual retention for snapper (Lutjanidae), grouper (Serranidae), jack (Carangidae), porgy (Sparidae), and surgeonfish (Acanthuridae). These relationships may be used to predict the effect of mesh sizes on catch rates. Because mesh size and shape greatly influenced catchability, regulating mesh size may provide a useful basis for managing the commercial trap fishery

    The MAPPINGS III Library of Fast Radiative Shock Models

    Full text link
    We present a new library of fully-radiative shock models calculated with the MAPPINGS III shock and photoionization code. The library consists of grids of models with shock velocities in the range v=100-1000 km/s and magnetic parameters B/sqrt(n) of 10^-4 - 10 muG cm^(3/2) for five different atomic abundance sets, and for a pre-shock density of 1.0 cm^(-3). Additionally, Solar abundance model grids have been calculated for densities of 0.01, 0.1, 10, 100, and 1000 cm^(-3) with the same range in v and B/sqrt(n). Each model includes components of both the radiative shock and its photoionized precursor, ionized by the EUV and soft X-ray radiation generated in the radiative gas. We present the details of the ionization structure, the column densities, and the luminosities of the shock and its precursor. Emission line ratio predictions are separately given for the shock and its precursor as well as for the composite shock+precursor structure to facilitate comparison with observations in cases where the shock and its precursor are not resolved. Emission line ratio grids for shock and shock+precursor are presented on standard line ratio diagnostic diagrams, and we compare these grids to observations of radio galaxies and a sample of AGN and star forming galaxies from the Sloan Digital Sky Survey. This library is available online, along with a suite of tools to enable the analysis of the shocks and the easy creation of emission line ratio diagnostic diagrams. These models represent a significant increase in parameter space coverage over previously available models, and therefore provide a unique tool in the diagnosis of emission by shocks.Comment: 39 pages, 34 figures, accepted for publication in ApJS, April 200

    Virtual Fly Brain: An ontology-linked schema of the Drosophila Brain

    Get PDF
    Drosophila neuro-anatomical data is scattered across a large, diverse literature dating back over 75 years and a growing number of community databases. Lack of a standardized nomenclature for neuro-anatomy makes comparison and searching this growing data-set extremely arduous. &#xd;&#xa;&#xd;&#xa;A recent standardization effort (BrainName; Manuscript in preparation) has produced a segmented, 3D model of the Drosophila brain annotated with a controlled vocabulary. We are formalizing these developments to produce a web-based ontology-linked atlas in which gross brain anatomy is defined, in part, by labeled volumes in a standard reference brain.&#xd;&#xa;&#xd;&#xa;We have developed new relations that allow us to use this well-defined gross anatomy as a substrate to define neuronal types according to where they fasciculate and innervate as well as to record the neurotransmitters they release, their lineage and functions. The resulting ontology will provide a vocabulary for annotation and a means for integrative queries of neurobiological data.&#xd;&#xa;&#xd;&#xa;The ontology and associated images, queries and annotations will be integrated into the Virtual Fly Brain website. This will provide a resource that biologists can use to browse annotated images of Drosophila neuro-anatomy and to get answers to questions about that anatomy and related data, without any need for ontology expertise.&#xd;&#xa
    corecore