1,781 research outputs found
Anomalous magnetic and weak magnetic dipole moments of the lepton in the simplest little Higgs model
We obtain analytical expressions, both in terms of parametric integrals and
Passarino-Veltman scalar functions, for the one-loop contributions to the
anomalous weak magnetic dipole moment (AWMDM) of a charged lepton in the
framework of the simplest little Higgs model (SLHM). Our results are general
and can be useful to compute the weak properties of a charged lepton in other
extensions of the standard model (SM). As a by-product we obtain generic
contributions to the anomalous magnetic dipole moment (AMDM), which agree with
previous results. We then study numerically the potential contributions from
this model to the lepton AMDM and AWMDM for values of the parameter
space consistent with current experimental data. It is found that they depend
mainly on the energy scale at which the global symmetry is broken and the
parameter, whereas there is little sensitivity to a mild change in
the values of other parameters of the model. While the AMDM is of the
order of , the real (imaginary) part of its AWMDM is of the order of
(). These values seem to be out of the reach of the
expected experimental sensitivity of future experiments.Comment: 23 pages, 11 figures, new analysis and References adde
The influence of differential rotation on the detectability of gravitational waves from the r-mode instability
Recently, it was shown that differential rotation is an unavoidable feature
of nonlinear r-modes. We investigate the influence of this differential
rotation on the detectability of gravitational waves emitted by a newly born,
hot, rapidly-rotating neutron star, as it spins down due to the r-mode
instability. We conclude that gravitational radiation may be detected by the
advanced laser interferometer detector LIGO if the amount of differential
rotation at the time the r-mode instability becomes active is not very high.Comment: 8 pages, 6 figures, revtex
Kinetic Ising System in an Oscillating External Field: Stochastic Resonance and Residence-Time Distributions
Experimental, analytical, and numerical results suggest that the mechanism by
which a uniaxial single-domain ferromagnet switches after sudden field reversal
depends on the field magnitude and the system size. Here we report new results
on how these distinct decay mechanisms influence hysteresis in a
two-dimensional nearest-neighbor kinetic Ising model. We present theoretical
predictions supported by numerical simulations for the frequency dependence of
the probability distributions for the hysteresis-loop area and the
period-averaged magnetization, and for the residence-time distributions. The
latter suggest evidence of stochastic resonance for small systems in moderately
weak oscillating fields.Comment: Includes updated results for Fig.2 and minor text revisions to the
abstract and text for clarit
Continuous partial trends and low-frequency oscillations of time series
International audienceThis paper presents a recent methodology developed for the analysis of the slow evolution of geophysical time series. The method is based on least-squares fitting of continuous line segments to the data, subject to flexible conditions, and is able to objectively locate the times of significant change in the series tendencies. The time distribution of these breakpoints may be an important set of parameters for the analysis of the long term evolution of some geophysical data, simplifying the intercomparison between datasets and offering a new way for the analysis of time varying spatially distributed data. Several application examples, using data that is important in the context of global warming studies, are presented and briefly discussed
Exploiting low-rank approximations of kernel matrics in denoising applicationS
The eigendecomposition of a kernel matrix can present a
computational burden in many kernel methods. Nevertheless
only the largest eigenvalues and corresponding eigenvectors
need to be computed. In this work we discuss the
Nystrom low-rank approximations of the kernel matrix and
its applications in KPCA denoising tasks. Furthermore, the
low-rank approximations have the advantage of being related
with a smaller subset of the training data which constitute
then a basis of a subspace. In a common algebraic
framework we discuss the different approaches to compute
the basis. Numerical simulations concerning the denoising
are presented to compare the discussed approaches.info:eu-repo/semantics/publishedVersio
15 years of experience with quality control of WLS fibres for the ATLAS Tile Calorimeter
We describe a test bench to measure the optical properties of scintillating and Wavelength-Shifting fibers, called the Fibrometer. The accuracy, stability and reproducibility were assessed, and the quality control of WLS fibers for the upgrade of the STIC luminosity monitor at DELPHI and for the Tile calorimeter of ATLAS is reported
A new physarum learner for network structure learning from biomedical data
A novel structure learning algorithm for Bayesian Networks based on a Physarum Learner is presented. The
length of the connections within an initially fully connected Physarum-Maze is taken as the inverse Pearson
correlation coefficient between the connected nodes. The Physarum Learner then estimates the shortest indirect
paths between each pair of nodes. In each iteration, a score of the surviving edges is incremented.
Finally, the highest scored connections are combined to form a Bayesian Network. The novel Physarum
Learner method is evaluated with different configurations and compared to the LAGD Hill Climber showing
comparable performance with respect to quality of training results and increased time efficiency for large data
sets
Intralobar Bronchopulmonary Sequestration with Associated Cardiac Malformation
O sequestro pulmonar intralobar geralmente não está associado a outras anomalias congénitas. Apresenta-se o caso clÃnico de um recém-nascido com diagnóstico pré-natal de anomalia pulmonar com desvio do mediastino,a quem foi diagnosticada uma coartação da aorta ao quinto dia de vida. A tomografia computorizada torácica revelou uma massa sólida na região basal posterior do lobo inferior esquerdo, sugerindo poder corresponder a um sequestro pulmonar intralobar. Foi submetido a cirurgia de correção da coartação da aorta e de ressecção do segmento correspondente de sequestro pulmonar.O exame anatomopatológico confirmou o diagnóstico de sequestro pulmonar intralobar. À data da redação deste trabalho, a criança tinha quatro anos de idade e estava clinicamente bem. O caso ilustra a associação de sequestro pulmonar intralobar a uma malformação cardÃaca
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