30,894 research outputs found
Running Gluon Mass from Landau Gauge Lattice QCD Propagator
The interpretation of the Landau gauge lattice gluon propagator as a massive
type bosonic propagator is investigated. Three different scenarios are
discussed: i) an infrared constant gluon mass; ii) an ultraviolet constant
gluon mass; iii) a momentum dependent mass. We find that the infrared data can
be associated with a massive propagator up to momenta MeV, with a
constant gluon mass of 723(11) MeV, if one excludes the zero momentum gluon
propagator from the analysis, or 648(7) MeV, if the zero momentum gluon
propagator is included in the data sets. The ultraviolet lattice data is not
compatible with a massive type propagator with a constant mass. The scenario of
a momentum dependent gluon mass gives a decreasing mass with the momentum,
which vanishes in the deep ultraviolet region. Furthermore, we show that the
functional forms used to describe the decoupling like solution of the
Dyson-Schwinger equations are compatible with the lattice data with similar
mass scales.Comment: Version to appear in J. Phys. G. New version include some rewriting
and new analysis. In particular, the section on the running mass is ne
Status epilepticus in the childhood. A Review of seven years
Rev Neurol. 2000 Mar 1-15;30(5):414-8.
[Status epilepticus in the childhood. A review of seven years]
[Article in Spanish]
Oliveira D, Oliveira MJ, Alves V, Temudo T.
Hospital Geral de Santo António, Porto, Portugal.
Abstract
INTRODUCTION: Status epilepticus is a neurological emergency that requires early and prompt treatment.
PATIENTS AND METHODS: This retrospective study includes 32 children treated for status epilepticus at Hospital Geral de Santo António, from January 1992 to December 1998. We evaluated the clinical features, duration, aetiology and prognostic.
RESULTS: Symptomatic or criptogenetic aetiology was present in 53% of children and idiopathic in 47%. 27% of episodes of status epilepticus were induced by fever. The most common neurological sequel was epilepsy (onset of new epilepsy in 20%; aggravated in 25%). Two children (10%) had major neurological sequelae after status epilepticus.
CONCLUSION: In our study the duration of status epilepticus and sequelae seems to be related with aetiology.
PMID: 10775965 [PubMed - indexed for MEDLINE
Scaling Invariance in a Time-Dependent Elliptical Billiard
We study some dynamical properties of a classical time-dependent elliptical
billiard. We consider periodically moving boundary and collisions between the
particle and the boundary are assumed to be elastic. Our results confirm that
although the static elliptical billiard is an integrable system, after to
introduce time-dependent perturbation on the boundary the unlimited energy
growth is observed. The behaviour of the average velocity is described using
scaling arguments
Roteiro dos participantes do curso: Custo de produção de café e leite.
Esta publicação é resultado de um trabalho de elaboração de curso de capacitação para agentes dinamizadores do desenvolvimento do território Vale do Jamari. A Secretaria de Desenvolvimento Territorial (SDT) estabeleceu dentre as diretrizes para a implantação do Programa de Desenvolvimento Territorial, promover a aquisição de capacidades, o desenvolvimento de capital social e a participação das populações territoriais, de modo a apoiar o processo de construção e implementação de planos territoriais de desenvolvimento. Nesse contexto, o objetivo do curso de Custo de produção de Café e Leite foi capacitar os agentes dinamizadores do desenvolvimento do território Vale do Jamari para atuarem como multiplicadores dos procedimentos de levantamento de custos de produção de café e leite.bitstream/CPAF-RO-2010/14323/1/doc110-curso-custodeproducaocafeeleite.pd
Inspecção, manutenção, conservação e reabilitação, de Obras de Arte
Pretende-se com esta comunicação abordar as estratégias de inspecção e de detecção de
anomalias, conservação, protecção, reparação e reabilitação de Obras de Arte. Pretendese
igualmente, descrever os danos mais frequentes nas pontes rodoviárias e analisar a
sua correlação com factores como a idade, tipologia, materiais, localização, etc. Descrevese
algumas soluções e técnicas de reabilitação de obras de arte em alvenaria de pedra e
em betão armado
Self-Similar Collapse of Scalar Field in Higher Dimensions
This paper constructs continuously self-similar solution of a spherically
symmetric gravitational collapse of a scalar field in n dimensions. The
qualitative behavior of these solutions is explained, and closed-form answers
are provided where possible. Equivalence of scalar field couplings is used to
show a way to generalize minimally coupled scalar field solutions to the model
with general coupling.Comment: RevTex 3.1, 15 pages, 3 figures; references adde
Scaling laws of human interaction activity
Even though people in our contemporary, technological society are depending
on communication, our understanding of the underlying laws of human
communicational behavior continues to be poorly understood. Here we investigate
the communication patterns in two social Internet communities in search of
statistical laws in human interaction activity. This research reveals that
human communication networks dynamically follow scaling laws that may also
explain the observed trends in economic growth. Specifically, we identify a
generalized version of Gibrat's law of social activity expressed as a scaling
law between the fluctuations in the number of messages sent by members and
their level of activity. Gibrat's law has been essential in understanding
economic growth patterns, yet without an underlying general principle for its
origin. We attribute this scaling law to long-term correlation patterns in
human activity, which surprisingly span from days to the entire period of the
available data of more than one year. Further, we provide a mathematical
framework that relates the generalized version of Gibrat's law to the long-term
correlated dynamics, which suggests that the same underlying mechanism could be
the source of Gibrat's law in economics, ranging from large firms, research and
development expenditures, gross domestic product of countries, to city
population growth. These findings are also of importance for designing
communication networks and for the understanding of the dynamics of social
systems in which communication plays a role, such as economic markets and
political systems.Comment: 20+7 pages, 4+2 figure
Indirect lattice evidence for the Refined Gribov-Zwanziger formalism and the gluon condensate in the Landau gauge
We consider the gluon propagator at various lattice sizes and
spacings in the case of pure SU(3) Yang-Mills gauge theories using the Landau
gauge fixing. We discuss a class of fits in the infrared region in order to
(in)validate the tree level analytical prediction in terms of the (Refined)
Gribov-Zwanziger framework. It turns out that an important role is played by
the presence of the widely studied dimension two gluon condensate
. Including this effect allows to obtain an acceptable fit up to
1 \'{a} 1.5 GeV, while corroborating the Refined Gribov-Zwanziger prediction
for the gluon propagator. We also discuss the infinite volume extrapolation,
leading to the estimate . As a byproduct, we can
also provide the prediction obtained at
the renormalization scale .Comment: 17 pages, 10 figures, updated version, accepted for publication in
Phs.Rev.
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