52,518 research outputs found

    Improving subject knowledge and subject pedagogic knowledge in employment based secondary initial teacher training in England

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    Each year in England about 6,000 trainee teachers qualify by undertaking an employment-based initial teacher training route (EBITT), where training is mainly school based. Government inspectors have found that trainees on this route are weaker in subject knowledge and subject pedagogic knowledge compared to trainees following the more traditional one year training course (PGCE) of which about a third of course time is University based. EBITT providers are currently seeking to improve the subject knowledge aspect of training. To support this work the TDA have published a model for developing trainees' subject knowledge for teaching and suggest that providers review their provision against the model. In addition EBITT providers must also meet a new requirement that the total training time should be a minimum of 60 days. This new requirement presents a challenge to EBITT providers as most of the subject knowledge enhancement will have to be school-based. This paper seeks to find out: - how trainee teachers acquire subject and subject pedagogic knowledge while based in a school and - whether teaching staff in schools have the required subject and subject pedagogic knowledge and skills for this enhanced role. Data have been collected from trainees, school-based mentors, school-based Initial Teacher Training Coordinators and University assessors over a one year period. Data about the way trainees acquire subject knowledge was interpreted against the TDA model. The study finds that: - trainees acquire subject and subject pedagogic knowledge in a variety of highly individualistic ways that suggests that the TDA model only partially explains what is happening in practice and - there is a significant training need to ensure schools are well equipped to deliver high quality subject focussed training.</p

    Condensation for a fixed number of independent random variables

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    A family of m independent identically distributed random variables indexed by a chemical potential \phi\in[0,\gamma] represents piles of particles. As \phi increases to \gamma, the mean number of particles per site converges to a maximal density \rho_c<\infty. The distribution of particles conditioned on the total number of particles equal to n does not depend on \phi (canonical ensemble). For fixed m, as n goes to infinity the canonical ensemble measure behave as follows: removing the site with the maximal number of particles, the distribution of particles in the remaining sites converges to the grand canonical measure with density \rho_c; the remaining particles concentrate (condensate) on a single site.Comment: 6 page

    Adaptive high-order finite element solution of transient elastohydrodynamic lubrication problems

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    This article presents a new numerical method to solve transient line contact elastohydrodynamic lubrication (EHL) problems. A high-order discontinuous Galerkin (DG) finite element method is used for the spatial discretization, and the standard Crank-Nicolson method is employed to approximate the time derivative. An h-adaptivity method is used for grid adaptation with the time-stepping, and the penalty method is employed to handle the cavitation condition. The roughness model employed here is a simple indentation, which is located on the upper surface. Numerical results are presented comparing the DG method to standard finite difference (FD) techniques. It is shown that micro-EHL features are captured with far fewer degrees of freedom than when using low-order FD methods

    Distributed feedback lasers

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    A ridge waveguide distributed feedback laser was developed in InGaAsP. These devices have demonstrated CW output powers over 7 mW with threshold currents as low as 60 mA at 25 C. Measurements of the frequency response of these devices show a 3 dB bandwidth of about 2 GHz, which may be limited by the mount. The best devices have a single mode spectra over the entire temperature range tested with a side mode suppression of about 20 dB in both CW and pulsed modes. The design of this device, including detailed modeling of the ridge guide structure, effective index calculations, and a discussion of the grating configuration are presented. Also, the fabrication of the devices is presented in some detail, especially the fabrication of and subsequent growth over the grating. In addition, a high frequency fiber pigtailed package was designed and tested, which is a suitable prototype for a commercial package

    Extracting predictive models from marked-p free-text documents at the Royal Botanic Gardens, Kew, London

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    In this paper we explore the combination of text-mining, un-supervised and supervised learning to extract predictive models from a corpus of digitised historical floras. These documents deal with the nomenclature, geographical distribution, ecology and comparative morphology of the species of a region. Here we exploit the fact that portions of text in the floras are marked up as different types of trait and habitat. We infer models from these different texts that can predict different habitat-types based upon the traits of plant species. We also integrate plant taxonomy data in order to assist in the validation of our models. We have shown that by clustering text describing the habitat of different floras we can identify a number of important and distinct habitats that are associated with particular families of species along with statistical significance scores. We have also shown that by using these discovered habitat-types as labels for supervised learning we can predict them based upon a subset of traits, identified using wrapper feature selection

    The Economic Impact of Invasive Species in the Ornamental Commodity in Puerto Rico: Towards Establishing a Multidimensional Framework for Data Collection and Analysis

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    The ornamental commodity in Puerto Rico is valued for its economic contribution in the agricultural sector, its contribution to the esthetics of natural scenarios that impact the tourism sector, and for its environmental role. In the fiscal year 2001, ornamentals generated 4.8% of the total Agricultural Gross Product. In that year the production value at farm level was 34.1million,theexportvalue34.1 million, the export value 0.5 million, and the import value $11.5 millions. Of the local production value, 1.5% was exported and 34.3% of the ornamental local market value was imported. The active trade traffic in Puerto Rico is a factor that increases the risk of the introduction of invasive species that affect the agricultural sector. It is necessary to estimate the economic impact of the established invasive species and those with high potential for introduction. The economic analysis must consider the impact on production, on market, and on the environment. The direct and indirect impact on market and non-market areas has to be estimated. The study presented in this paper pretends to gather economic data on the ornamental commodity and biological data on invasive pests and diseases to initiate the development of a comprehensive species risk management framework that incorporates the economic impact of invasive species.invasive species, ornamental, economic impact analysis, Crop Production/Industries,

    Spacetime Supersymmetry in a nontrivial NS-NS Superstring Background

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    In this paper we consider superstring propagation in a nontrivial NS-NS background. We deform the world sheet stress tensor and supercurrent with an infinitesimal B_{\mu\nu} field. We construct the gauge-covariant super-Poincare generators in this background and show that the B_{\mu\nu} field spontaneously breaks spacetime supersymmetry. We find that the gauge-covariant spacetime momenta cease to commute with each other and with the spacetime supercharges. We construct a set of "magnetic" super-Poincare generators that are conserved for constant field strength H_{\mu\nu\lambda}, and show that these generators obey a "magnetic" extension of the ordinary supersymmetry algebra.Comment: 13 pages, Latex. Published versio

    Interactions between unidirectional quantized vortex rings

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    We have used the vortex filament method to numerically investigate the interactions between pairs of quantized vortex rings that are initially traveling in the same direction but with their axes offset by a variable impact parameter. The interaction of two circular rings of comparable radii produce outcomes that can be categorized into four regimes, dependent only on the impact parameter; the two rings can either miss each other on the inside or outside, or they can reconnect leading to final states consisting of either one or two deformed rings. The fraction of of energy went into ring deformations and the transverse component of velocity of the rings are analyzed for each regime. We find that rings of very similar radius only reconnect for a very narrow range of the impact parameter, much smaller than would be expected from geometrical cross-section alone. In contrast, when the radii of the rings are very different, the range of impact parameters producing a reconnection is close to the geometrical value. A second type of interaction considered is the collision of circular rings with a highly deformed ring. This type of interaction appears to be a productive mechanism for creating small vortex rings. The simulations are discussed in the context of experiments on colliding vortex rings and quantum turbulence in superfluid helium in the zero temperature limit

    Engaging men with penile cancer in qualitative research: reflections from an interview-based study.

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    To explore the challenges of engaging men with penile cancer in qualitative interview research
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