2,919 research outputs found
Complements of tori and Klein bottles in the 4-sphere that have hyperbolic structure
Many noncompact hyperbolic 3-manifolds are topologically complements of links
in the 3-sphere. Generalizing to dimension 4, we construct a dozen examples of
noncompact hyperbolic 4-manifolds, all of which are topologically complements
of varying numbers of tori and Klein bottles in the 4-sphere. Finite covers of
some of those manifolds are then shown to be complements of tori and Klein
bottles in other simply-connected closed 4-manifolds. All the examples are
based on a construction of Ratcliffe and Tschantz, who produced 1171 noncompact
hyperbolic 4-manifolds of minimal volume. Our examples are finite covers of
some of those manifolds.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-41.abs.htm
F and D Values with Explicit Flavor Symmetry Breaking and \Delta s Contents of Nucleons
We propose a new model for describing baryon semi-leptonic decays for
estimating and values with explicit breaking effects of both SU(3) and
SU(2) flavor symmetry, where all possible SU(3) and SU(2) breaking effects are
induced from an effective interaction. An overall fit including the weak
magnetism form factor yields and with
d.o.f. with and . The spin content of strange quarks is estimated from the
obtained values and , and the nucleon spin problem is re-examined.
Furthermore, the unmeasured values of and for other hyperon
semi-leptonic decays are predicted from this new formula.Comment: 15 pages, 1 figure, final version to appear in PR
Salem numbers and arithmetic hyperbolic groups
In this paper we prove that there is a direct relationship between Salem
numbers and translation lengths of hyperbolic elements of arithmetic hyperbolic
groups that are determined by a quadratic form over a totally real number
field. As an application we determine a sharp lower bound for the length of a
closed geodesic in a noncompact arithmetic hyperbolic n-orbifold for each
dimension n. We also discuss a "short geodesic conjecture", and prove its
equivalence with "Lehmer's conjecture" for Salem numbers.Comment: The exposition in version 3 is more compact; this shortens the paper:
26 pages now instead of 37. A discussion on Lehmer's problem has been added
in Section 1.2. Final version, to appear is Trans. AM
Older people, regeneration and health and well-being. Case study of Salford Partnership Board for Older People
This study sat within a national project aimed at demonstrating that expert knowledge housed within universities can make a positive impact in urban communities around four themes: Community Cohesion, Crime, Enterprise and Health & Wellbeing. It involved the Universities of Salford, Northumbria, Central Lancashire, Manchester Metropolitan University and Bradford. The project aimed to address key urban regeneration challenges in the North of England through inter-disciplinary collaboration between partner universities and practitioner organisations. It also sought to build a long term strategic alliance between core university partners.
Within each of the four project areas there were a number of smaller projects each focusing on the relationship between the theme and urban regeneration.
This study sought to establish how partnership boards for older people address the health and well being needs of people over 50 years of age including how health and wellbeing are defined; strategies older people adopt to change service providers' actions; learning by service providers about the involvement of older people on Boards; and how this influences practice. The main activity within this study was to interview Salford Partnership Board members. The findings informed further development of the Board
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