4,297 research outputs found
The Running Coupling from Lattice Gauge Theory
From an accurate determination of the inter-quark potential, one can study
the running coupling constant for a range of -values and hence estimate the
scale \Lambda_{\msbar} . Detailed results are presented for pure
gauge theory to illustrate the method.Comment: 8 pages Liverpool preprint LTH279, 24 Jan 1992 (1 figure not
enclosed) (Accepted for publication in Phys Lett B
Perturbation Theory for Fat-link Fermion Actions
We discuss weak coupling perturbation theory for lattice actions in which the
fermions couple to smeared gauge links. The normally large integrals that
appear in lattice perturbation theory are drastically reduced. Even without
detailed calculation, it is easy to determine to good accuracy the scale of the
logarithms that appear in cases where an anomalous dimension is present. We
describe several 1-loop examples for fat-link Wilson and clover fermions.
including the additive mass shift, the relation between the lattice and MSbar
quark masses, and the axial current renormalization factor () for
light-light and static-light currents.Comment: LATTICE99(Improvement and Renormalization); 3 pages, no figure
Generalized Rayleigh and Jacobi processes and exceptional orthogonal polynomials
We present four types of infinitely many exactly solvable Fokker-Planck
equations, which are related to the newly discovered exceptional orthogonal
polynomials. They represent the deformed versions of the Rayleigh process and
the Jacobi process.Comment: 17 pages, 4 figure
The string tension in SU(N) gauge theory from a careful analysis of smearing parameters
We report a method to select optimal smearing parameters before production
runs and discuss the advantages of this selection for the determination of the
string tension.Comment: Contribution to Lat97 poster session, title was 'How to measure the
string tension', 3 pages, 5 colour eps figure
Baryonic Operators for Lattice Simulations
The construction of baryonic operators for determining the N* excitation
spectrum is discussed. The operators are designed with one eye towards
maximizing overlaps with the low-lying states of interest, and the other eye
towards minimizing the number of sources needed in computing the required quark
propagators. Issues related to spin identification are outlined. Although we
focus on tri-quark baryon operators, the construction method is applicable to
both mesons and penta-quark operators.Comment: 3 pages, poster presented at Lattice2003(spectrum), Tsukuba, Japan,
July 15-19, 200
Transparency, Civic Capital and Political Accountability: A Virtuous Relation?
Our paper investigates the intertwined relation among
transparency, civic capital and political accountability in a
large sample of Italian municipalities using a new indicator
of institutional transparency. Firstly, we test the hypothesis
that civic capital affects transparency of public administrations;
secondly, we verify whether in municipalities where
civic capital is high, citizensâ attention toward government
accountability is also high, making it politically unfeasible to
disregard the demand for transparency. We find that civic
capital positively affects transparency and the latter, in turn,
is politically rewarding for the local administrators only conditional
to the level of civic capital. Our findings are robust
to different samples and endogeneity concerns
Spectral density analysis of time correlation functions in lattice QCD using the maximum entropy method
We study various aspects of extracting spectral information from time
correlation functions of lattice QCD by means of Bayesian inference with an
entropic prior, the maximum entropy method (MEM). Correlator functions of a
heavy-light meson-meson system serve as a repository for lattice data with
diverse statistical quality. Attention is given to spectral mass density
functions, inferred from the data, and their dependence on the parameters of
the MEM. We propose to employ simulated annealing, or cooling, to solve the
Bayesian inference problem, and discuss practical issues of the approach.Comment: 11 pages, 30 figure files (eps), some references added and updated,
requires REVTeX 4.0 and prerequisites (AMS-LaTeX 2.0, graphicx, dcolumn, bm)
see http://publish.aps.org/revtex4
PMMA-based bone cements and the problem of joint arthroplasty infections: Status and new perspectives
Polymethyl methacrylate (PMMA)-based bone cement is a biomaterial that has been used over the last 50 years to stabilize hip and knee implants or as a bone filler. Although PMMA-based bone cement is widely used and allows a fast-primary fixation to the bone, it does not guarantee a mechanically and biologically stable interface with bone, and most of all it is prone to bacteria adhesion and infection development. In the 1970s, antibiotic-loaded bone cements were introduced to reduce the infection rate in arthroplasty; however, the eciency of antibiotic-containing bone cement is still a debated issue. For these reasons, in recent years, the scientific community has investigated new approaches to impart antibacterial properties to PMMA bone cement. The aim of this review is to summarize the current status regarding antibiotic-loaded PMMA-based bone cements, fill the gap regarding the lack of data on antibacterial bone cement, and explore the progress of antibacterial bone cement formulations, focusing attention on the new perspectives. In particular, this review highlights the innovative study of composite bone cements containing inorganic antibacterial and bioactive phases, which are a fascinating alternative that can impart both osteointegration and antibacterial properties to PMMA-based bone cement
Lunar laser ranging in infrfared at hte Grasse laser station
For many years, lunar laser ranging (LLR) observations using a green
wavelength have suffered an inhomogeneity problem both temporally and
spatially. This paper reports on the implementation of a new infrared detection
at the Grasse LLR station and describes how infrared telemetry improves this
situation. Our first results show that infrared detection permits us to densify
the observations and allows measurements during the new and the full Moon
periods. The link budget improvement leads to homogeneous telemetric
measurements on each lunar retro-reflector. Finally, a surprising result is
obtained on the Lunokhod 2 array which attains the same efficiency as Lunokhod
1 with an infrared laser link, although those two targets exhibit a
differential efficiency of six with a green laser link
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