133 research outputs found
An Interdisciplinary Framework for Impacting Older Adults Health and Physical Activity
The exploration of feasible and cost-effective strategies is warranted to mitigate rising healthcare costs and lessen the impact of chronic diseases, functional decline, and disability in older adults. The overwhelming sedentariness of older adults is accompanied by a lack of expertise by healthcare professionals in exercise programming that acknowledge factors influencing physical activity (PA) patterns. We present a framework for a nursing/exercise science interdisciplinary effort to increase PA and improve health in older adults via the delivery of individually tailored exercise programming for an 8-week intervention. Results from this study will be integral in translating effective interdisciplinary efforts across diverse healthcare settings
On the symmetries of special holonomy sigma models
In addition to superconformal symmetry, (1,1) supersymmetric two-dimensional
sigma models on special holonomy manifolds have extra symmetries that are in
one-to-one correspondence with the covariantly constant forms on these
manifolds. The superconformal algebras extended by these symmetries close as
W-algebras, i.e. they have field-dependent structure functions. It is shown
that it is not possible to write down cohomological equations for potential
quantum anomalies when the structure functions are field-dependent. In order to
do this it is necessary to linearise the algebras by treating composite
currents as generators of additional symmetries. It is shown that all cases can
be linearised in a finite number of steps, except for G_2 and SU(3). Additional
problems in the quantisation procedure are briefly discussed.Comment: 16 pages. Abstract improved and a few typographical errors correcte
Self-dual Einstein Spaces, Heavenly Metrics and Twistors
Four-dimensional quaternion-Kahler metrics, or equivalently self-dual
Einstein spaces M, are known to be encoded locally into one real function h
subject to Przanowski's Heavenly equation. We elucidate the relation between
this description and the usual twistor description for quaternion-Kahler
spaces. In particular, we show that the same space M can be described by
infinitely many different solutions h, associated to different complex (local)
submanifolds on the twistor space, and therefore to different (local)
integrable complex structures on M. We also study quaternion-Kahler
deformations of M and, in the special case where M has a Killing vector field,
show that the corresponding variations of h are related to eigenmodes of the
conformal Laplacian on M. We exemplify our findings on the four-sphere S^4, the
hyperbolic plane H^4 and on the "universal hypermultiplet", i.e. the
hypermultiplet moduli space in type IIA string compactified on a rigid
Calabi-Yau threefold.Comment: 44 pages, 1 figure; misprints correcte
Electron attachment to POCI<sub>3</sub>: Measurement and theoretical analysis of rate constants and branching ratios as a function of gas pressure and temperature, electron temperature, and electron energy.
Multi-Instanton Calculus and the AdS/CFT Correspondence in N=4 Superconformal Field Theory
We present a self-contained study of ADHM multi-instantons in SU(N) gauge theory, especially the novel interplay with supersymmetry and the large-N limit. We give both field- and string-theoretic derivations of the N=4 supersymmetric multi-instanton action and collective coordinate integration measure. As a central application, we focus on certain n-point functions G_n, n=16, 8 or 4, in N=4 SU(N) gauge theory at the conformal point (as well as on related higher-partial-wave correlators); these are correlators in which the 16 exact supersymmetric and superconformal fermion zero modes are saturated. In the large-N limit, for the first time in any 4-dimensional theory, we are able to evaluate all leading-order multi-instanton contributions exactly. We find compelling evidence for Maldacena's conjecture: (1) The large-N k-instanton collective coordinate space has the geometry of a single copy of AdS_5 x S^5. (2) The integration measure on this space includes the partition function of 10-dimensional N=1 SU(k) gauge theory dimensionally reduced to 0 dimensions, matching the description of D-instantons in Type IIB string theory. (3) In exact agreement with Type IIB string calculations, at the k-instanton level, G_n = \sqrt{N} g^8 k^{n-7/2} e^{2\pi ik\tau} \sum_{d|k} d^{-2} F_n(x_1,...,x_n), where F_n is identical to a convolution of n bulk-to-boundary supergravity propagators
N=2 supergravity in five dimensions revisited
We construct matter-coupled N=2 supergravity in five dimensions, using the
superconformal approach. For the matter sector we take an arbitrary number of
vector-, tensor- and hyper-multiplets. By allowing off-diagonal vector-tensor
couplings we find more general results than currently known in the literature.
Our results provide the appropriate starting point for a systematic search for
BPS solutions, and for applications of M-theory compactifications on Calabi-Yau
manifolds with fluxes.Comment: 35 pages; v.2: A sign changed in a bilinear fermion term in (5.7
Theory of Ultracold Superstrings
The combination of a vortex line in a one-dimensional optical lattice with
fermions bound to the vortex core makes up an ultracold superstring. We give a
detailed derivation of the way to make this supersymmetric string in the
laboratory. In particular, we discuss the presence of a fermionic bound state
in the vortex core and the tuning of the laser beams needed to achieve
supersymmetry. Moreover, we discuss experimental consequences of supersymmetry
and identify the precise supersymmetry in the problem. Finally, we make the
mathematical connection with string theory.Comment: 16 pages, 9 figures, important factor 2 corrected, accepted for
publication in PR
Regularisation, the BV method, and the antibracket cohomology
We review the Lagrangian Batalin--Vilkovisky method for gauge theories. This
includes gauge fixing, quantisation and regularisation. We emphasize the role
of cohomology of the antibracket operation. Our main example is gravity,
for which we also discuss the solutions for the cohomology in the space of
local integrals. This leads to the most general form for the action, for
anomalies and for background charges.Comment: 12 pages, LaTeX, Preprint-KUL-TF-94/2
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