627 research outputs found

    Supporting Practicing School Counselor’s Skill Development: A Hip Hop and Spoken Word Professional Development Intervention

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    Given the paucity of professional development (PD) opportunities, gaps in cultural competence, and deterioration of direct counseling service opportunities for many school counselors, it is reasonable to conjecture that there is an inadvertent abandonment of skill development and related student outcomes. This mixed-methods study sought to evaluate the effectiveness of an innovative PD series for school counselors, exploring participants\u27 self-efficacy in counseling skill use and cross-cultural competence. The researchers administered a multi-session PD to school counselors in an Urban, Northeast School District in the US. Data from pre- and post-training surveys, vignettes, and post-training focus groups indicated a significant decrease in participants’ self-efficacy pre- to post-training. Further, results suggest participants learned innovative practice, practiced humanistic counseling skills, and understood new potential for student growth

    Protostellar collapse: A comparison between SPH and AMR calculations

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    The development of parallel supercomputers allows today the detailed study of the collapse and the fragmentation of prestellar cores with increasingly accurate numerical simulations. Thanks to the advances in sub-millimeter observations, a wide range of observed initial conditions enable us to study the different modes of low-mass star formation. The challenge for the simulations is to reproduce the observational results. Two main numerical methods, namely AMR and SPH, are widely used to simulate the collapse and the fragmentation of prestellar cores. We compare thoroughly these two methods within their standard framework. We use the AMR code RAMSES and the SPH code DRAGON. Our physical model is as simple as possible and consists of an isothermal sphere rotating around the z-axis. We first study the conservation of angular momentum as a function of the resolution. Then, we explore a wide range of simulation parameters to study the fragmentation of prestellar cores. There seems to be a convergence between the two methods, provided resolution in each case is sufficient. Resolution criteria adapted to our physical cases, in terms of resolution per Jeans mass, for an accurate description of the formation of protostellar cores are deduced from the present study. This convergence is encouraging for future work in simulations of low-mass star formation, providing the aforementioned criteria are fulfilled. Higher resolution figures can be downloaded at http://www-dapnia.cea.fr/Projets/COAST/paper_amrvssph.pdfComment: 16 pages, 16 figures, accepted for publication in A&

    The supernova remnant CTB 37B and its associated magnetar CXOU J171405.7-381031: evidence for a magnetar-driven remnant

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    We discuss in this Letter the association of the candidate magnetar CXOU J171405.7-381031 with the supernova remnant CTB 37B. The recent detection of the period derivative of the object allowed an estimation of a young characteristic age of only 1000yr\sim 1000 yr. This value is too small to be compatible even with the minimum radius of the remnant 10pc\geq 10 pc, the value corresponding to the {\it lower} limit of the estimated distance of 10.2±3.5kpc10.2 \pm 3.5 kpc, unless the true distance happens to be even smaller than the lower limit. We argue that a consistent scenario for the remnant origin, in which the latter is powered by the energy injected by a young magnetar, is indeed more accurate to explain the young age, and points out to its non-standard (i.e. magnetar-driven) nature.Comment: 6 pp., 1 figure, to appear in RAA Letter

    Developing trauma-informed teacher education in England

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    Trauma-informed practice in education is an area of growing interest in England and internationally. Embracing trauma-informed practice in schools requires trauma and related content to be included in teacher education. Over a period of eight years, a short course was developed and incorporated into the teacher preparation programmes at a large university in England. Through methods of teacher educator self-study and autoethnography, we examine the process of the course’s development and identify mechanisms, enablers and barriers to change in the current policy context of teacher education in England. Important factors that supported change were the gradual development, external collaboration, positive outcomes as a warrant and source of motivation, the development of champions and enthusiasts for trauma-informed practice, and departmental leadership support. Barriers to the development were the constraints of prescribed content on initial teacher education courses, prevailing practices in some schools and settings, challenges in adapting material suitably for all education phases, and some beginning teachers’ responses to personally relevant course content. The successful introduction of the short course demonstrates that inclusion of trauma-informed content in initial teacher education is possible even in an unfavourable policy environment

    The evolution of mass loaded supernova remnants: II. Temperature dependent mass injection rates

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    We investigate the evolution of spherically symmetric supernova remnants in which mass loading takes place due to conductively driven evaporation of embedded clouds. Numerical simulations reveal significant differences between the evolution of conductively mass loaded and the ablatively mass loaded remnants studied in Paper I. A main difference is the way in which conductive mass loading is extinguished at fairly early times, once the interior temperature of the remnant falls below ~ 107 K. Thus, at late times remnants that ablatively mass load are dominated by loaded mass and thermal energy, while those that conductively mass load are dominated by swept-up mass and kinetic energy. Simple approximations to the remnant evolution, complementary to those in Paper I, are given

    The contribution of supernova remnants to the galactic cosmic ray spectrum

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    The supernova paradigm for the origin of galactic cosmic rays has been deeply affected by the development of the non-linear theory of particle acceleration at shock waves. Here we discuss the implications of applying such theory to the calculation of the spectrum of cosmic rays at Earth as accelerated in supernova remnants and propagating in the Galaxy. The spectrum is calculated taking into account the dynamical reaction of the accelerated particles on the shock, the generation of magnetic turbulence which enhances the scattering near the shock, and the dynamical reaction of the amplified field on the plasma. Most important, the spectrum of cosmic rays at Earth is calculated taking into account the flux of particles escaping from upstream during the Sedov-Taylor phase and the adiabatically decompressed particles confined in the expanding shell and escaping at later times. We show how the spectrum obtained in this way is well described by a power law in momentum with spectral index close to -4, despite the concave shape of the instantaneous spectra of accelerated particles. On the other hand we also show how the shape of the spectrum is sensible to details of the acceleration process and environment which are and will probably remain very poorly known.Comment: 19 pages, 8 figures, published version (references updated

    An adjustable law of motion for relativistic spherical shells

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    A classical and a relativistic law of motion for an advancing shell are deduced applying the thin layer approximation. A new parameter connected with the quantity of absorbed matter in the expansion is introduced; this allows of matching theory and observation.Comment: 15 pages, 10 figures and article in press; Central European Journal of Physics 201

    Gas Accretion is Dominated by Warm Ionized Gas in Milky Way-Mass Galaxies at z ~ 0

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    We perform high-resolution hydrodynamic simulations of a Milky Way-mass galaxy in a fully cosmological setting using the adaptive mesh refinement code, Enzo, and study the kinematics of gas in the simulated galactic halo. We find that the gas inflow occurs mostly along filamentary structures in the halo. The warm-hot (10^5 K 10^6 K) ionized gases are found to dominate the overall mass accretion in the system (with dM/dt = 3-5 M_solar/yr) over a large range of distances, extending from the virial radius to the vicinity of the disk. Most of the inflowing gas (by mass) does not cool, and the small fraction that manages to cool does so primarily close to the galaxy (R <~ 20 kpc), perhaps comprising the neutral gas that may be detectable as, e.g., high-velocity clouds. The neutral clouds are embedded within larger, accreting filamentary flows, and represent only a small fraction of the total mass inflow rate. The inflowing gas has relatively low metallicity (Z/Z_solar < 0.2). The outer layers of the filamentary inflows are heated due to compression as they approach the disk. In addition to the inflow, we find high-velocity, metal-enriched outflows of hot gas driven by supernova feedback. Our results are consistent with observations of halo gas at low z.Comment: 10 pages including 5 figures, submitted to Ap

    川の中の昆虫たち

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    There is provided a novel derivative of 2-acetoxybenzoic acid, i.e., 1-O-(2\u27-acetoxy)benzoyl-α-D-2-deoxyglucopyranose, which is suitable for the attainment of high 2-acetoxybenzoic acid blood levels without irritation of the gastrointestinal lining

    Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks

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    We describe a semi-analytical approach to non-linear diffusive shock acceleration in the case in which nuclei other than protons are also accelerated. The structure of the shock is determined by the complex interplay of all nuclei, and in turn this shock structure determines the spectra of all components. The magnetic field amplification upstream is described as due to streaming instability of all nuclear species. The amplified magnetic field is then taken into account for its dynamical feedback on the shock structure as well as in terms of the induced modification of the velocity of the scattering centers that enters the particle transport equation. The spectra of accelerated particles are steep enough to be compared with observed cosmic ray spectra only if the magnetic field is sufficiently amplified and the scattering centers have high speed in the frame of the background plasma. We discuss the implications of this generalized approach on the structure of the knee in the all-particle cosmic ray spectrum, which we interpret as due to an increasingly heavier chemical composition above 101510^{15}eV. The effects of a non trivial chemical composition at the sources on the gamma ray emission from a supernova remnant when gamma rays are of hadronic origin are also discussed.Comment: 23 pages, 5 figures, minor changes to reflect the published versio
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