675 research outputs found
Evidence for hard chiral logarithms in quenched lattice QCD
We present the first direct evidence that quenched QCD differs from full QCD
in the chiral () limit, as predicted by chiral perturbation
theory, from our quenched lattice QCD simulations at . We
measured the spectrum of light hadrons on ,
and , using staggered quarks of masses ,
and . The pion masses showed clear evidence for logarithmic
violations of the PCAC relation , as predicted by
quenched chiral perturbation theory. The dependence on spatial lattice volume
precludes this being a finite size effect. No evidence was seen for such chiral
logarithms in the behaviour of the chiral condensate
.Comment: 10 pages, 4 figures, uuencoded compressed postscript fil
BioSphincter a Regenerative Medicine Approach to Treat FI
A healthy sphincter physiology is a complex interplay between neural and muscle population, responsible for relaxation and contraction, which allow feces to pass and reestablishment of closure. The loss of integrity of neuromuscular functionality or cellular component results in fecal incontinence (FI). The current available treatments have been disappointing in long-term relief. This chapter represents a regenerative medicine approach to this debilitating disease, wherein a new internal anal sphincter (IAS) BioSphincter™ is bioengineered from the patient’s own cells and implanted. It results in long-term restoration of the cellular integrity and reinstatement of the physiological function of the IAS. Following implantation in rodents, the engineered sphincters became vascularized and maintained their phenotype and functionality. The developed IAS BioSphincter™ were validated to treat the FI in large animals and successfully restored anorectal functionality. According to NIH/NIDDK, one out of seven people report to health care providers complaining of fecal incontinence. This chapter elucidates the long road in developing on implantable bioengineered IAS “BioSphincter™” that would benefit and improve the quality of life of a large socially distressed segment of the population
The Weakly Coupled Gross-Neveu Model with Wilson Fermions
The nature of the phase transition in the lattice Gross-Neveu model with
Wilson fermions is investigated using a new analytical technique. This involves
a new type of weak coupling expansion which focuses on the partition function
zeroes of the model. Its application to the single flavour Gross-Neveu model
yields a phase diagram whose structure is consistent with that predicted from a
saddle point approach. The existence of an Aoki phase is confirmed and its
width in the weakly coupled region is determined. Parity, rather than chiral
symmetry breaking naturally emerges as the driving mechanism for the phase
transition.Comment: 15 pages including 1 figur
Coupling the Deconfining and Chiral Transitions
The Polyakov loop and the chiral condensate are used as order parameters to
explore analytically the possible phase structure of finite temperature QCD.
Nambu-Jona-Lasinio models in a background temporal gauge field are combined
with a Polyakov loop potential in a form suitable for both the lattice and the
continuum. Three possible behaviors are found: a first-order transition, a
second-order transition, and a region with both transitions.Comment: 4 pages, LaTeX, 4 Postscript Figures, uuencoded, Contribution to
Lattice 95 Conference Proceeding
Critical Dynamics of the Hybrid Monte Carlo Algorithm
We investigate the critical dynamics of the Hybrid Monte Carlo algorithm
approaching the chiral limit of standard Wilson fermions. Our observations are
based on time series of lengths O(5000) for a variety of observables. The
lattice sizes are 16^3 x 32 and 24^3 x 40. We work at beta=5.6, and
kappa=0.156, 0.157, 0.1575, 0.158, with 0.83 > m_pi/m_rho > 0.55. We find
surprisingly small integrated autocorrelation times for local and extended
observables. The dynamical critical exponent of the exponential
autocorrelation time is compatible with 2. We estimate the total computational
effort to scale between V^2 and V^2.25 towards the chiral limit.Comment: 3 pages, Latex with espcrc2.sty and postscript figures, Talk given at
Lattice 9
Warm-Started Optimized Trajectory Planning for ASVs
We consider warm-started optimized trajectory planning for autonomous surface
vehicles (ASVs) by combining the advantages of two types of planners: an A*
implementation that quickly finds the shortest piecewise linear path, and an
optimal control-based trajectory planner. A nonlinear 3-degree-of-freedom
underactuated model of an ASV is considered, along with an objective functional
that promotes energy-efficient and readily observable maneuvers. The A*
algorithm is guaranteed to find the shortest piecewise linear path to the goal
position based on a uniformly decomposed map. Dynamic information is
constructed and added to the A*-generated path, and provides an initial guess
for warm starting the optimal control-based planner. The run time for the
optimal control planner is greatly reduced by this initial guess and outputs a
dynamically feasible and locally optimal trajectory.Comment: Accepted to the 12th IFAC Conference on Control Applications in
Marine Systems, Robotics, and Vehicles (CAMS 2019
Properties of the a1 Meson from Lattice QCD
We determine the mass and decay constant of the meson using Monte Carlo
simulation of lattice QCD. We find MeV and , in good agreement with experiment.Comment: 9 page uu-encoded compressed postscript file. version appearing in
Phys. Rev. Lett. 74 (1995) 459
A game theoretic approach for optimizing density of remote radio heads in user centric cloud-based radio access network
In this paper, we develop a game theoretic formulation for empowering cloud enabled HetNets with adaptive Self Organizing Network (SON) capabilities. SON capabilities for intelligent and efficient radio resource management is a fundamental design pillar for the emerging 5G cellular networks. The C-RAN system model investigated in this paper consists of ultra-dense remote radio heads (RRHs) overlaid by central baseband units that can be collocated with much less densely deployed overlaying macro base-stations (BSs). It has been recently demonstrated that under a user centric scheduling mechanism, C-RAN inherently manifests the trade-off between Energy Efficiency (EE) and Spectral Efficiency (SE) in terms of RRH density. The key objective of the game theoretic framework developed in this paper is to dynamically optimize the trade-off between the EE and the SE of the C- RAN. More specifically, for an ultra-dense C- RAN based HetNet, the density of active RRHs should be carefully dimensioned to maximize the SE. However, the density of RRHs which maximizes the SE may not necessarily be optimal in terms of the EE. In order to strike a balance between these two performance determinants, we develop a game theoretic formulation by employing a Nash bargaining framework. The two metrics of interest, SE and EE, are modeled as virtual players in a bargaining problem and the Nash bargaining solution for RRH density is determined. In the light of the optimization outcome we evaluate corresponding key performance indicators through numerical results. These results offer insights for a C-RAN designer on how to optimally design a SON mechanism to achieve a desired trade-off level between the SE and the EE in a dynamic fashion
Shortest Constrained Inter-Domain Traffic Engineering Label Switched Paths Status of This Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards " (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust’s Legal Provisions Relating to IETF Documents in effect on the date of publication of this documen
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