229 research outputs found
Independent Loop Invariants for 2+1 Gravity
We identify an explicit set of complete and independent Wilson loop
invariants for 2+1 gravity on a three-manifold , with
a compact oriented Riemann surface of arbitrary genus . In the
derivation we make use of a global cross section of the -principal
bundle over Teichm\"uller space given in terms of Fenchel-Nielsen coordinates.Comment: 11pp, 2 figures (postscript, compressed and uu-encoded), TeX,
Pennsylvania State University, CGPG-94/7-
On fusion algebra of chiral models
We discuss some algebraic setting of chiral models in terms of
the statistical dimensions of their fields. In particular, the conformal
dimensions and the central charge of the chiral models are
calculated from their braid matrices. Futhermore, at level K=2, we present the
characteristic polynomials of their fusion matrices in a factored form.Comment: 11 pages, ioplpp
Community professionals' management of client care : a mixed-methods systematic review
This is the final draft, after peer-review, of a manuscript published in Journal of Health Services Research & Policy. The definitive version, detailed above, is available online at www.rsmjournals.com.Peer reviewedPostprin
New Loop Representations for 2+1 Gravity
Since the gauge group underlying 2+1-dimensional general relativity is
non-compact, certain difficulties arise in the passage from the connection to
the loop representations. It is shown that these problems can be handled by
appropriately choosing the measure that features in the definition of the loop
transform. Thus, ``old-fashioned'' loop representations - based on ordinary
loops - do exist. In the case when the spatial topology is that of a two-torus,
these can be constructed explicitly; {\it all} quantum states can be
represented as functions of (homotopy classes of) loops and the scalar product
and the action of the basic observables can be given directly in terms of
loops.Comment: 28pp, 1 figure (postscript, compressed and uuencoded), TeX,
Pennsylvania State University, CGPG-94/5-
Dynamical Stability of Six-Dimensional Warped Brane-Worlds
We study a generalization of the Randall-Sundrum mechanism for generating the
weak/Planck hierarchy, which uses two rather than one warped extra dimension,
and which requires no negative tension branes. A 4-brane with one exponentially
large compact dimension plays the role of the Planck brane. We investigate the
dynamical stability with respect to graviton, graviphoton and radion modes. The
radion is shown to have a tachyonic instability for certain models of the
4-brane stress-energy, while it is stable in others, and massless in a special
case. If stable, its mass is in the milli-eV range, for parameters of the model
which solve the hierarchy problem. The radion is shown to couple to matter with
gravitational strength, so that it is potentially detectable by
submillimeter-range gravity experiments. The radion mass can be increased using
a bulk scalar field in the manner of Goldberger and Wise, but only to order
MeV, due to the effect of the large extra dimension. The model predicts a
natural scale of 10^{13} GeV on the 4-brane, making it a natural setting for
inflation from the ultraviolet brane.Comment: 28 pages, 7 figure
Sigma-model for Generalized Composite p-branes
A multidimensional gravitational model containing several dilatonic scalar
fields and antisymmetric forms is considered. The manifold is chosen in the
form M = M_0 x M_1 x ... x M_n, where M_i are Einstein spaces (i > 0). The
block-diagonal metric is chosen and all fields and scale factors of the metric
are functions on M_0. For the forms composite (electro-magnetic) p-brane ansatz
is adopted. The model is reduced to gravitating self-interacting sigma-model
with certain constraints. In pure electric and magnetic cases the number of
these constraints is m(m - 1)/2 where m is number of 1-dimensional manifolds
among M_i. In the "electro-magnetic" case for dim M_0 = 1, 3 additional m
constraints appear. A family of "Majumdar-Papapetrou type" solutions governed
by a set of harmonic functions is obtained, when all factor-spaces M_k are
Ricci-flat. These solutions are generalized to the case of non-Ricci-flat M_0
when also some additional "internal" Einstein spaces of non-zero curvature are
added to M. As an example exact solutions for D = 11 supergravity and related
12-dimensional theory are presented.Comment: 33 pages, Latex. Some corrections and rearrangements are mad
フィールドにおける3次元歩行動作解析システムの開発
The purpose of this study was to clarify the effectiveness and
possible problems that may occur when using the walking movement
analysis system of three dimensions in the field. Cinematography was
performed using an optical signal with four sets of digital camcorders
synchronously. First, in order to clarify measurement accuracy, the
error of distance and angle in the actual value and calculation value,
was examined. Next, the walking movements during free walking in
the field using this system was analyzed employing ten young men,and
the variables were compared with studies preceding this study. The
following results were obtained:
1.It is more desirable to digitize using large projectors, such as a
huge screen, when analyzing fine angles or distance of images of the
whole body that is photographed.
2.It was thought that if the definition of each joint angle or the
height of toe at heel contact is the same, the value of each variable
acquired is similar to preceding studies. Therefore,it can be concluded
that this walking movement analysis system of three dimensions is
effective.
When analyzing images, it is necessary to raise measurement
accuracy and to consider error factors irrespective of the field or
laboratory
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