228,566 research outputs found
A Note on Hamilton-Jacobi Formalism and D-brane Effective Actions
We first review the canonical formalism with general space-like hypersurfaces
developed by Dirac by rederiving the Hamilton-Jacobi equations which are
satisfied by on-shell actions defined on such hypersurfaces. We compare the
case of gravitational systems with that of the flat space. Next, we remark as a
supplement to our previous results that the effective actions of D-brane and
M-brane given by arbitrary embedding functions are on-shell actions of
supergravities.Comment: 12 pages, 1 figure, section 3 is extended, references added,
published versio
Deformed fields and Moyal construction of deformed super Virasoro algebra
Studied is the deformation of super Virasoro algebra proposed by Belov and
Chaltikhian. Starting from abstract realizations in terms of the FFZ type
generators, various connections of them to other realizations are shown,
especially to deformed field representations, whose bosonic part generator is
recently reported as a deformed string theory on a noncommutative world-sheet.
The deformed Virasoro generators can also be expressed in terms of ordinary
free fields in a highly nontrivial way.Comment: neutral fields are replaced by complex fields almost everywhere in
Sects. 6 and
Inference with Constrained Hidden Markov Models in PRISM
A Hidden Markov Model (HMM) is a common statistical model which is widely
used for analysis of biological sequence data and other sequential phenomena.
In the present paper we show how HMMs can be extended with side-constraints and
present constraint solving techniques for efficient inference. Defining HMMs
with side-constraints in Constraint Logic Programming have advantages in terms
of more compact expression and pruning opportunities during inference.
We present a PRISM-based framework for extending HMMs with side-constraints
and show how well-known constraints such as cardinality and all different are
integrated. We experimentally validate our approach on the biologically
motivated problem of global pairwise alignment
Distribution of Si, Fe, and Ni in the Intracluster Medium of the Coma Cluster
We studied the distributions of Si, Fe, and Ni in the intracluster medium
(ICM) of the Coma cluster, one of the largest clusters in the nearby universe,
using XMM-Newton data up to 0.5 r180 and Suzaku data of the central region up
to 0.16 r180. Using the flux ratios of Ly alpha of H-like Si and 7.8 keV blend
to K alpha of He-like Fe, the abundance ratios of Si to Fe and Ni to Fe of the
ICM were derived using APEC model v2.0.1. The Si/Fe ratio in the ICM of the
Coma cluster shows no radial gradient. The emission weighted averages of the
Si/Fe ratio in the ICM within 0.0--0.2 r180, 0.2--0.5 r180, and 0.0--0.5 r180
are 0.97 +- 0.11, 1.05 +- 0.36 and 0.99 +- 0.13, respectively, in solar units
using the solar abundance of Lodders (2003). These values are close to those of
smaller clusters and groups of galaxies. Using the Suzaku data of the central
region, the derived Ni/Fe ratio of the ICM is 0.6--1.5 in solar units,
according to the same solar abundance table. The systematic difference in the
derived abundance ratios by different plasma codes are about 10%. Therefore,
for the ICM in the Coma cluster, the abundance pattern of Si, Fe, and Ni is
consistent with the same mixture of the yields of SN II and SN Ia in our
Galaxy. Within 0.5 r180}, the cumulative iron-mass-to-light ratio increases
with radius, and its radial profile is similar to those of relaxed smaller
clusters with cD galaxies at their center. Considering the observed Si/Fe
ratio, the cumulative metal-mass-to-light ratios at 0.5 r180 are compared with
theoretical expectations.Comment: 10 pages, 7 figures, accepted for publication in PAS
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