3,616 research outputs found
Black-Hole Solutions with Scalar Hair in Einstein-Scalar-Gauss-Bonnet Theories
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
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
We prove that the Frobenius--Perron operator of the cusp map
, (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
the spectrum of in the Hardy space in the disk
\{z\in\C:|z-q|<1+q\} is the union of the segment 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
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
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
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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