14,599 research outputs found

    Tracing the journey: two School-based counsellors ‘coming out’ of the counselling room. An ethnographic enquiry within a UK inner-city secondary school

    Get PDF
    Mental health issues for young people in the UK are relatively common, being experienced by upwards of 10% of people aged between 5 and 15 (NHS Digital, 2018). Evidence for the benefits of school-based counselling in UK schools is also steadily mounting, as is interest in and support for the idea. In spite of this, its provision within schools in England remains insecure and it has been subject to a recurring cycle of development and decline since its inception in the 1960s. This dissertation comprises a personalised account of the researchers’ own shared journey as experienced counsellors who were new to an inner-city secondary school setting and were encountering difficulties working effectively in that new context. Our initial question was therefore: How could we make sense of the difficulties we were experiencing? As our research progressed, social and cultural processes in the school community were identified, and a further question emerged: How might any of the understanding gained be used as a bridge to better connection in this setting? The research goes beyond the focus on one-one counselling that has been the emphasis of the majority of school-based counselling research and practice. It is believed that as a result the study may illuminate some of the cultural intersections and complexities inherent in the school-based counselling context that the researchers believe require greater attention if the offer of counselling within schools is to become a more secure provision. This intention led the two researchers to adopt a reflexive and ethnographic, insider research approach for the current study, which was undertaken in an inner-city setting in an area of significant deprivation with a very diverse student population. Data analysis began with early data collection, in line with a Grounded Theory approach (Charmaz, 2006 ; Glaser & Strauss, 1967) and our ongoing analysis shaped the continuing data collection. A new theory about adult-to -adolescent process termed ‘tenuous contact’ was constructed and a post-qualification conversion diploma was developed and delivered based on the research findings, which will equip counsellors to work in this sector. The study will be of interest to professionals concerned with school-based counselling and, more widely, it is hoped that it will contribute to an understanding of social and contextual issues in offering mental health support within education

    Hydra: An Adaptive--Mesh Implementation of PPPM--SPH

    Get PDF
    We present an implementation of Smoothed Particle Hydrodynamics (SPH) in an adaptive-mesh PPPM algorithm. The code evolves a mixture of purely gravitational particles and gas particles. The code retains the desirable properties of previous PPPM--SPH implementations; speed under light clustering, naturally periodic boundary conditions and accurate pairwise forces. Under heavy clustering the cycle time of the new code is only 2--3 times slower than for a uniform particle distribution, overcoming the principal disadvantage of previous implementations\dash a dramatic loss of efficiency as clustering develops. A 1000 step simulation with 65,536 particles (half dark, half gas) runs in one day on a Sun Sparc10 workstation. The choice of time integration scheme is investigated in detail. A simple single-step Predictor--Corrector type integrator is most efficient. A method for generating an initial distribution of particles by allowing a a uniform temperature gas of SPH particles to relax within a periodic box is presented. The average SPH density that results varies by ∌±1.3\sim\pm1.3\%. We present a modified form of the Layzer--Irvine equation which includes the thermal contribution of the gas together with radiative cooling. Tests of sound waves, shocks, spherical infall and collapse are presented. Appropriate timestep constraints sufficient to ensure both energy and entropy conservation are discussed. A cluster simulation, repeating Thomas andComment: 29 pp, uuencoded Postscrip

    Integrals of Motion for Critical Dense Polymers and Symplectic Fermions

    Full text link
    We consider critical dense polymers L(1,2){\cal L}(1,2). We obtain for this model the eigenvalues of the local integrals of motion of the underlying Conformal Field Theory by means of Thermodynamic Bethe Ansatz. We give a detailed description of the relation between this model and Symplectic Fermions including the indecomposable structure of the transfer matrix. Integrals of motion are defined directly on the lattice in terms of the Temperley Lieb Algebra and their eigenvalues are obtained and expressed as an infinite sum of the eigenvalues of the continuum integrals of motion. An elegant decomposition of the transfer matrix in terms of a finite number of lattice integrals of motion is obtained thus providing a reason for their introduction.Comment: 53 pages, version accepted for publishing on JSTA

    Smoothed Particle Hydrodynamics in cosmology: a comparative study of implementations

    Get PDF
    We analyse the performance of twelve different implementations of Smoothed Particle Hydrodynamics (SPH) using seven tests designed to isolate key hydrodynamic elements of cosmological simulations which are known to cause the SPH algorithm problems. In order, we consider a shock tube, spherical adiabatic collapse, cooling flow model, drag, a cosmological simulation, rotating cloud-collapse and disc stability. In the implementations special attention is given to the way in which force symmetry is enforced in the equations of motion. We study in detail how the hydrodynamics are affected by different implementations of the artificial viscosity including those with a shear-correction modification. We present an improved first-order smoothing-length update algorithm that is designed to remove instabilities that are present in the Hernquist and Katz (1989) algorithm. For all tests we find that the artificial viscosity is the most important factor distinguishing the results from the various implementations. The second most important factor is the way force symmetry is achieved in the equation of motion. Most results favour a kernel symmetrization approach. The exact method by which SPH pressure forces are included has comparatively little effect on the results. Combining the equation of motion presented in Thomas and Couchman (1992) with a modification of the Monaghan and Gingold (1983) artificial viscosity leads to an SPH scheme that is both fast and reliable.Comment: 30 pages, 26 figures and 9 tables included. Submitted to MNRAS. Postscript version available at ftp://phobos.astro.uwo.ca/pub/etittley/papers/sphtest.ps.g

    The effect of radiative cooling on scaling laws of X-ray groups and clusters

    Get PDF
    We have performed cosmological simulations in a ΛCDM cosmology with and without radiative cooling in order to study the effect of cooling on the cluster scaling laws. Our simulations consist of 4.1 million particles each of gas and dark matter within a box size of 100 h-1 Mpc, and the run with cooling is the largest of its kind to have been evolved to z = 0. Our cluster catalogs both consist of over 400 objects and are complete in mass down to ~1013 h-1 M☉. We contrast the emission-weighted temperature-mass (Tew-M) and bolometric luminosity-temperature (Lbol-Tew) relations for the simulations at z = 0. We find that radiative cooling increases the temperature of intracluster gas and decreases its total luminosity, in agreement with the results of Pearce et al. Furthermore, the temperature dependence of these effects flattens the slope of the Tew-M relation and steepens the slope of the Lbol-Tew relation. Inclusion of radiative cooling in the simulations is sufficient to reproduce the observed X-ray scaling relations without requiring excessive nongravitational energy injection

    Chandra and XMM-Newton Observations of the Double Cluster Abell 1758

    Full text link
    Abell 1758 was classified as a single rich cluster of galaxies by Abell, but a ROSAT observation showed that this system consists of two distinct clusters (A1758N and A1758S) separated by approximately 8\arcmin (a projected separation of 2 Mpc in the rest frame of the clusters). Only a few galaxy redshifts have been published for these two clusters, but the redshift of the Fe lines in the Chandra and XMM-Newton spectra shows that the recessional velocities of A1758N and A1758S are within 2,100 km s−1^{-1}. Thus, these two clusters most likely form a gravitationally bound system, but our imaging and spectroscopic analyses of the X-ray data do not reveal any sign of interaction between the two clusters. The Chandra and XMM-Newton observations show that A1758N and A1758S are both undergoing major mergers. A1758N is in the late stages of a large impact parameter merger between two 7 keV clusters. The two remnant cores have a projected separation of 800 kpc. Based on the measured pressure jumps preceding the two cores, they are receding from one another at less than 1,600 km s−1^{-1}. The two cores are surrounded by hotter gas (kT=9\mathrm{kT}=9--12 keV) that was probably shock heated during the early stages of the merger. The gas entropy in the two remnant cores is comparable with the central entropy observed in dynamically relaxed clusters, indicating that the merger-induced shocks stalled as they tried to penetrate the high pressure cores of the two merging systems.Each core also has a wake of low entropy gas indicating that this gas was ram pressure stripped without being strongly shocked (abridged). (A copy of the paper with higher resolution images is available at http://asc.harvard.edu/~lpd/a1758.ps).Comment: paper plus 13 figure

    Solvable Critical Dense Polymers

    Get PDF
    A lattice model of critical dense polymers is solved exactly for finite strips. The model is the first member of the principal series of the recently introduced logarithmic minimal models. The key to the solution is a functional equation in the form of an inversion identity satisfied by the commuting double-row transfer matrices. This is established directly in the planar Temperley-Lieb algebra and holds independently of the space of link states on which the transfer matrices act. Different sectors are obtained by acting on link states with s-1 defects where s=1,2,3,... is an extended Kac label. The bulk and boundary free energies and finite-size corrections are obtained from the Euler-Maclaurin formula. The eigenvalues of the transfer matrix are classified by the physical combinatorics of the patterns of zeros in the complex spectral-parameter plane. This yields a selection rule for the physically relevant solutions to the inversion identity and explicit finitized characters for the associated quasi-rational representations. In particular, in the scaling limit, we confirm the central charge c=-2 and conformal weights Delta_s=((2-s)^2-1)/8 for s=1,2,3,.... We also discuss a diagrammatic implementation of fusion and show with examples how indecomposable representations arise. We examine the structure of these representations and present a conjecture for the general fusion rules within our framework.Comment: 35 pages, v2: comments and references adde

    Integrable and Conformal Boundary Conditions for sl(2) A-D-E Lattice Models and Unitary Minimal Conformal Field Theories

    Get PDF
    Integrable boundary conditions are constructed for the critical A-D-E lattice models of statistical mechanics. In particular, using techniques associated with the Temperley-Lieb algebra and fusion, a set of explicit boundary Boltzmann weights which satisfies the boundary Yang-Baxter equation is obtained for each boundary condition. When appropriately specialised, these boundary weights, each of which depends on three spins, decompose into more natural two-spin edge weights. The specialised boundary conditions are also naturally in one-to-one correspondence with the conformal boundary conditions of sl(2) unitary minimal conformal field theories. Supported by this and further evidence, we conclude that, in the continuum scaling limit, the integrable boundary conditions provide realisations of the complete set of conformal boundary conditions in the corresponding field theories
    • 

    corecore