2,623 research outputs found

    Enthusing and inspiring with reusable kinaesthetic activities

    Get PDF
    We describe the experiences of three University projects that use a style of physical, non-computer based activity to enthuse and teach school students computer science concepts. We show that this kind of activity is effective as an outreach and teaching resource even when reused across different age/ability ranges, in lecture and workshop formats and for delivery by different people. We introduce the concept of a Reusable Outreach Object (ROO) that extends Reusable Learning Objects. and argue for a community effort in developing a repository of such objects

    Accumulation layer profiles at InAs polar surfaces

    Get PDF
    High resolution electron energy loss spectroscopy, dielectric theory simulations, and charge profile calculations have been used to study the accumulation layer and surface plasmon excitations at the In-terminated (001)-(4 × 1) and (111)A-(2 × 2) surfaces of InAs. For the (001) surface, the surface state density is 4.0 ± 2.0 × 1011 cm – 2, while for the (111)A surface it is 7.5 ± 2.0 × 1011 cm – 2, these values being independent of the surface preparation procedure, bulk doping level, and substrate temperature. Changes of the bulk Fermi level with temperature and bulk doping level do, however, alter the position of the surface Fermi level. Ion bombardment and annealing of the surface affect the accumulation layer only through changes in the effective bulk doping level and the bulk momentum scattering rate, with no discernible changes in the surface charge density

    Making it easier for school children to be active and eat well

    Full text link

    No evidence for intense, cold accretion onto YSOs from measurements of Li in T-Tauri stars

    Full text link
    We have used medium resolution spectra to search for evidence that proto-stellar objects accrete at high rates during their early 'assembly phase'. Models predict that depleted lithium and reduced luminosity in T-Tauri stars are key signatures of 'cold' high-rate accretion occurring early in a star's evolution. We found no evidence in 168 stars in NGC 2264 and the Orion Nebula Cluster for strong lithium depletion through analysis of veiling corrected 6708 angstrom lithium spectral line strengths. This suggests that 'cold' accretion at high rates (M_dot > 5 x 10-4 M_sol yr-1) occurs in the assembly phase of fewer than 0.5 per cent of 0.3 < M < 1.9 M_sol stars. We also find that the dispersion in the strength of the 6708 angstrom lithium line might imply an age spread that is similar in magnitude to the apparent age spread implied by the luminosity dispersion seen in colour magnitude diagrams. Evidence for weak lithium depletion (< 10 per cent in equivalent width) that is correlated with luminosity is also apparent, but we are unable to determine whether age spreads or accretion at rates less than 5 x 10-4 M_sol yr-1 are responsible.Comment: 13 pages, 10 figures; Accepted for publication in Monthly Notices of the Royal Astronomical Society, 2013 June 0

    Pre-main-sequence isochrones -- II. Revising star and planet formation timescales

    Full text link
    We have derived ages for 13 young (<30 Myr) star-forming regions and find they are up to a factor two older than the ages typically adopted in the literature. This result has wide-ranging implications, including that circumstellar discs survive longer (~10-12 Myr) and that the average Class I lifetime is greater (~1 Myr) than currently believed. For each star-forming region we derived two ages from colour-magnitude diagrams. First we fitted models of the evolution between the zero-age main-sequence and terminal-age main-sequence to derive a homogeneous set of main-sequence ages, distances and reddenings with statistically meaningful uncertainties. Our second age for each star-forming region was derived by fitting pre-main-sequence stars to new semi-empirical model isochrones. For the first time (for a set of clusters younger than 50 Myr) we find broad agreement between these two ages, and since these are derived from two distinct mass regimes that rely on different aspects of stellar physics, it gives us confidence in the new age scale. This agreement is largely due to our adoption of empirical colour-Teff relations and bolometric corrections for pre-main-sequence stars cooler than 4000 K. The revised ages for the star-forming regions in our sample are: ~2 Myr for NGC 6611 (Eagle Nebula; M 16), IC 5146 (Cocoon Nebula), NGC 6530 (Lagoon Nebula; M 8), and NGC 2244 (Rosette Nebula); ~6 Myr for {\sigma} Ori, Cep OB3b, and IC 348; ~10 Myr for {\lambda} Ori (Collinder 69); ~11 Myr for NGC 2169; ~12 Myr for NGC 2362; ~13 Myr for NGC 7160; ~14 Myr for {\chi} Per (NGC 884); and ~20 Myr for NGC 1960 (M 36).Comment: 28 pages, 18 figures, 34 tables, accepted for publication in MNRAS. All photometric catalogues presented in this paper are available online at the Cluster Collaboration homepage http://www.astro.ex.ac.uk/people/timn/Catalogues

    Off the couch and on the move: global public health and the medicalisation of nature

    Get PDF
    In May 2004 the World Health Organization officially launched the ‘Global Strategy on Diet, Physical Activity and Health’. Lying at its heart is the recognition that many of the risk factors associated with non-communicable diseases, particularly poor diet and physical inactivity, have begun to move beyond the confines of the West. It was this apparent shift in the epidemiological boundaries of such diseases, along with fears over the socalled ‘double burden’ that they presented to some nations, that finally prompted the WHO to develop such a far reaching strategy. This paper adds to the on-going debate surrounding this important issue by drawing on the concepts of medicalisation, governmentality and the spatiality of scientific knowledge to explore one particular element of it: namely, the identification of nature as a setting for the promotion of physical activity. We adopt this perspective because we are concerned to understand the ways in which the knowledge and practice of the new public health travels. As our analysis reveals, in many Western nations the natural environment has emerged as an important ‘transactional zone’ where the governmental imperative for the production of fit and active bodies coalesces with the individual desire to be healthy. However, while it is apparent that this physical activity discourse increasingly operates throughout the globe, there is less evidence of an equivalent discourse that promotes the health-related benefits of nature. We argue that this is significant because it helps us recognise that contemporary public health discourse has a distinct geography

    Germs, genes and postcolonial geographies: reading the return of tuberculosis to Leicester, UK, 2001

    Full text link
    This paper is inspired by an outbreak of pulmonary tuberculosis in the British East Midlands city of Leicester in 2001. In an era characterized by unprecedented advances in Western medical science an event of this kind might appear surprising. It challenges the feeling of wellbeing held in many Western countries, particularly in relation to diseases that appear both temporally and spatially distant. The paper examines how the event was reported in regional and national newspaper media and considers the significance attached to scale in the interactions between experts, the media and the public. In our analysis we mobilize a particular reading based on two biological metaphors, the membrane and the gene. We use this reading to reconsider the connectivity between disease, nation and identity in a world that is increasingly fluid, mobile, anxious and uncertain
    • …
    corecore