25,305 research outputs found

    The Legacy of ERA, Privatization and the Policy Ratchet

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    This article explores the ways in which the neo-liberal impetus toward the privatization of state schooling signalled in the Education Reform Act 1988 (ERA) has become embedded in the English school system. Four main points are made. First, that ERA itself was of huge strategic rather than substantive importance as far as privatization is concerned. Second, by tracing the lineage of privatization from ERA onwards a 'ratchet' effect of small and incremental policy moves can be identified, which have disseminated, embedded and naturalized privatization within public sector provision. Third, that while privatization has been taken up and taken much further by New Labour than it had been by the Conservatives there are differences between the two sets of governments in the role of privatization in education policy and the role of the state. Fourth, the participation of private providers in the planning and delivery of state services has put the private sector at the very heart of policy. At points the article draws upon interviews conducted with private sector providers. © 2008 Sage Publications

    Analysis of the BK2(1430),a2(1320),f2(1270)B \to K^*_2(1430), a_2(1320), f_2(1270) form-factors with light-cone QCD sum rules

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    In this article, we study the BK2(1430)B \to K^*_2(1430), a2(1320)a_2(1320), f2(1270)f_2(1270) form-factors with the light-cone QCD sum rules, where the BB-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of the BB-meson light-cone distribution amplitude ϕ+(ω)\phi_+(\omega) have significant impacts on the values of the form-factors, and expect to obtain severe constraints on the parameters of the BB-meson light-cone distribution amplitudes from the experimental data in the future.Comment: 19 pages, 6 figures, slight revisio

    Photocurrent in conjugated polymers

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    Nonlinear photocurrent carriers in conjugated polymers, such as polarons, bipolarons and solitons, are considered at low photon energies where a tunnelling process is necessary. We show that polarons usually dominate the photocurrent I due to a novel electric field assisted tunnelling for which ln(I) ~ -E^{-2/3}. For near degenerate polymers an electric field E which exceeds the confinement potential and frequencies above twice the soliton energy, soliton tunnelling is favored. Photocurrent data can then be used to identify the remarkable phenomenon of soliton conduction.Comment: 4 pages, 2 eps figures, Revte

    Renormalizability of Effective Scalar Field Theory

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    We present a comprehensive discussion of the consistency of the effective quantum field theory of a single Z2Z_2 symmetric scalar field. The theory is constructed from a bare Euclidean action which at a scale much greater than the particle's mass is constrained only by the most basic requirements; stability, finiteness, analyticity, naturalness, and global symmetry. We prove to all orders in perturbation theory the boundedness, convergence, and universality of the theory at low energy scales, and thus that the theory is perturbatively renormalizable in the sense that to a certain precision over a range of such scales it depends only on a finite number of parameters. We then demonstrate that the effective theory has a well defined unitary and causal analytic S--matrix at all energy scales. We also show that redundant terms in the Lagrangian may be systematically eliminated by field redefinitions without changing the S--matrix, and discuss the extent to which effective field theory and analytic S--matrix theory are actually equivalent. All this is achieved by a systematic exploitation of Wilson's exact renormalization group flow equation, as used by Polchinski in his original proof of the renormalizability of conventional φ4\varphi^4-theory.Comment: 80 pages, TeX, OUTP-93-23P, CERN-TH.7067/93. Many minor revisions, and several new paragraph

    Operator Relations for SU(3) Breaking Contributions to K and K* Distribution Amplitudes

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    We derive constraints on the asymmetry a1 of the momentum fractions carried by quark and antiquark in K and K* mesons in leading twist. These constraints follow from exact operator identities and relate a1 to SU(3) breaking quark-antiquark-gluon matrix elements which we determine from QCD sum rules. Comparing our results to determinations of a1 from QCD sum rules based on correlation functions of quark currents, we find that, for a1^\parallel(K*) the central values agree well and come with moderate errors, whereas for a1(K) and a1^\perp(K*) the results from operator relations are consistent with those from quark current sum rules, but come with larger uncertainties. The consistency of results confirms that the QCD sum rule method is indeed suitable for the calculation of a1. We conclude that the presently most accurate predictions for a1 come from the direct determination from QCD sum rules based on correlation functions of quark currents and are given by: a1(K) = 0.06\pm 0.03, a1^\parallel(K*) = 0.03\pm 0.02, a1^\perp(K*) = 0.04\pm 0.03.Comment: 21 page