3,590 research outputs found

    Black-Hole Solutions with Scalar Hair in Einstein-Scalar-Gauss-Bonnet Theories

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    In the context of the Einstein-scalar-Gauss-Bonnet theory, with a general coupling function between the scalar field and the quadratic Gauss-Bonnet term, we investigate the existence of regular black-hole solutions with scalar hair. Based on a previous theoretical analysis, that studied the evasion of the old and novel no-hair theorems, we consider a variety of forms for the coupling function (exponential, even and odd polynomial, inverse polynomial, and logarithmic) that, in conjunction with the profile of the scalar field, satisfy a basic constraint. Our numerical analysis then always leads to families of regular, asymptotically-flat black-hole solutions with non-trivial scalar hair. The solution for the scalar field and the profile of the corresponding energy-momentum tensor, depending on the value of the coupling constant, may exhibit a non-monotonic behaviour, an unusual feature that highlights the limitations of the existing no-hair theorems. We also determine and study in detail the scalar charge, horizon area and entropy of our solutions.Comment: PdfLatex file, 29 Pages, 18 figures, the analysis was extended to study the scalar charge, horizon area and entropy of our solutions, comments added, typos corrected, version to appear in Physical Review

    Law students' clinic experience: Is it all hype in relation to performance on lack-letter law exams

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    Does legal clinic experience really have a positive contribution to students’ performance on black-letter law examinations? This is the question we set out to answer by reference to data we collected from current law students at the University of East London (UEL). The sample is small and our findings are limited. However, we hope the results inform fellow legal education clinicians of the perceived and real benefits that law clinic students derive from their legal clinic experience and provide a basis for further research on this subject, such as the correlation between clinical legal education and black-letter law. It is important, now more than ever, that universities adapt to ensure that they are fit for purpose in equipping students with the skills they need for the workplace as well as sound theory and in-depth substantive contents of their subjects of study

    The resonance spectrum of the cusp map in the space of analytic functions

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    We prove that the Frobenius--Perron operator UU of the cusp map F:[−1,1]→[−1,1]F:[-1,1]\to[-1,1], F(x)=1−2∣x∣F(x)=1-2\sqrt{|x|} (which is an approximation of the Poincar\'e section of the Lorenz attractor) has no analytic eigenfunctions corresponding to eigenvalues different from 0 and 1. We also prove that for any q∈(0,1)q\in(0,1) the spectrum of UU in the Hardy space in the disk \{z\in\C:|z-q|<1+q\} is the union of the segment [0,1][0,1] and some finite or countably infinite set of isolated eigenvalues of finite multiplicity.Comment: Submitted to JMP; The description of the spectrum in some Hardy spaces is adde

    Resonances of the cusp family

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    We study a family of chaotic maps with limit cases the tent map and the cusp map (the cusp family). We discuss the spectral properties of the corresponding Frobenius--Perron operator in different function spaces including spaces of analytic functions. A numerical study of the eigenvalues and eigenfunctions is performed.Comment: 14 pages, 3 figures. Submitted to J.Phys.

    School self-evaluation for school improvement: Examining the measuring properties of the LEAD surveys

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    Research evidence suggests school self-evaluation with the participation of school stakeholders could improve teaching and learning. Identification and use of appropriate self-evaluation frameworks, however, is not an easy task for schools. Such a framework, the LEAD School Effectiveness Surveys, has been developed by Independent Schools Victoria in Australia. The LEAD suite of school stakeholder surveys enables schools to evaluate their overall effectiveness in several domains and make informed decisions for school improvement. This article evaluates the reliability as well as the face, content and construct validity of the LEAD surveys and discusses the ways in which school self-evaluation results could contribute to school improvement. Data were gathered from a total of 119,749 students, teaching staff, general and parents taking the LEAD Surveys in 112 independent (non-government) schools and followed a five-year longitudinal design from 2009 to 2013. The results support the reliability as well as the face, content and construct validity of the LEAD surveys. The importance of evaluating the measuring properties of instruments used for school self-evaluation is discussed and suggestions for school self-evaluation are provided. Independent Schools Victoria (Australia

    Critical Opalescence in Baryonic QCD Matter

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    We show that critical opalescence, a clear signature of second-order phase transition in conventional matter, manifests itself as critical intermittency in QCD matter produced in experiments with nuclei. This behaviour is revealed in transverse momentum spectra as a pattern of power laws in factorial moments, to all orders, associated with baryon production. This phenomenon together with a similar effect in the isoscalar sector of pions (sigma mode) provide us with a set of observables associated with the search for the QCD critical point in experiments with nuclei at high energies.Comment: 7 pages, 1 figur
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