3,216 research outputs found
Unitary chiral dynamics in decays into and the role of the scalar mesons
We make a theoretical study of the \J decays into ,
, and using the techniques of
the chiral unitary approach stressing the important role of the scalar
resonances dynamically generated through the final state interaction of the two
pseudoscalar mesons. We also discuss the importance of new mechanisms with
intermediate exchange of vector and axial-vector mesons and the role played by
the OZI rule in the \J\phi\pi\pi vertex, quantifying its effects. The results
nicely reproduce the experimental data for the invariant mass distributions in
all the channels considered.Comment: Prepared for the 10th International Symposium on Meson-Nucleon
Physics and the Structure of the Nucleo
Imperfect Imitation Can Enhance Cooperation
The promotion of cooperation on spatial lattices is an important issue in
evolutionary game theory. This effect clearly depends on the update rule: it
diminishes with stochastic imitative rules whereas it increases with
unconditional imitation. To study the transition between both regimes, we
propose a new evolutionary rule, which stochastically combines unconditional
imitation with another imitative rule. We find that, surprinsingly, in many
social dilemmas this rule yields higher cooperative levels than any of the two
original ones. This nontrivial effect occurs because the basic rules induce a
separation of timescales in the microscopic processes at cluster interfaces.
The result is robust in the space of 2x2 symmetric games, on regular lattices
and on scale-free networks.Comment: 4 pages, 4 figure
Clues for the existence of two resonances
The axial vector meson was studied within the chiral unitary
approach, where it was shown that it has a two-pole structure. We reanalyze the
high-statistics WA3 experiment at 63 GeV, which
established the existence of both and , and we show that
it clearly favors our two-pole interpretation. We also reanalyze the
traditional K-matrix interpretation of the WA3 data and find that the good fit
of the data obtained there comes from large cancellations of terms of unclear
physical interpretation.Comment: published version in PRD; typos corrected; title changed to "Clues
for the existence of two resonances
Local covariant density functional constrained by the relativistic Hartree-Fock theory
The recent progress in the localized covariant density functional constrained
by the relativistic Hartree-Fock theory is briefly presented by taking the
Gamow-Teller resonance in 90Zr as an example. It is shown that the constraints
introduced by the Fock terms into the particle-hole residual interactions are
straight forward and robust.Comment: 4 pages, 1 figure, Proceedings of NSD12, Opatija, Croatia, 9-13 July
201
Diagnosis and Decision-Making in Telemedicine
This article provides an analysis of the skills that health professionals and patients employ in reaching diagnosis and decision-making in telemedicine consultations. As governmental priorities continue to emphasize patient involvement in the management of their disease, there is an increasing need to accurately capture the provider–patient interactions in clinical encounters. Drawing on conversation analysis of 10 video-mediated consultations in 3 National Health Service settings in England, this study examines the interaction between patients, General Practitioner (GPs), nurses, and consultants during diagnosis and decision-making, with the aim to identify the range of skills that participants use in the process and capture the interprofessional communication and patient involvement in the diagnosis and decision-making phases of telemedicine consultations. The analysis shows that teleconsultations enhance collaborative working among professionals and enable GPs and nurses to develop their skills and actively participate in diagnosis and decision-making by contributing primary care–specific knowledge to the consultation. However, interprofessional interaction may result in limited patient involvement in decisionmaking. The findings of this study can be used to inform training programs in telemedicine that focus on the development of effective skills for professionals and the provision of information to patients
Nuclear charge-exchange excitations in localized covariant density functional theory
The recent progress in the studies of nuclear charge-exchange excitations
with localized covariant density functional theory is briefly presented, by
taking the fine structure of spin-dipole excitations in 16O as an example. It
is shown that the constraints introduced by the Fock terms of the relativistic
Hartree-Fock scheme into the particle-hole residual interactions are
straightforward and robust.Comment: 4 pages, 1 figure, Proceedings of INPC2013, Florence, Italy, 2-7 June
201
Hidden gauge formalism for the radiative decays of axial-vector mesons
The radiative decay of the axial-vector resonances into a pseudoscalar meson
and a photon is studied using the vector meson Lagrangian obtained from the
hidden gauge symmetry (HGS) formalism. The formalism is well suited to study
this problem since it deals with pseudoscalar and vector mesons in a unified
way, respecting chiral invariance. We show explicitly the gauge invariance of
the set of diagrams that appear in the approach and evaluate the radiative
decay width of the a1(1260) and b1(1235) axial vector meson resonances into pi
gamma. We also include the contribution of loops involving anomalous couplings
and compare the results to those obtained previously within another formalism.Comment: 24 pages, 6 tables, 11 figure
TRUFAS, a wavelet based algorithm for the rapid detection of planetary transits
Aims: We describe a fast, robust and automatic detection algorithm, TRUFAS,
and apply it to data that are being expected from the CoRoT mission. Methods:
The procedure proposed for the detection of planetary transits in light curves
works in two steps: 1) a continuous wavelet transformation of the detrended
light curve with posterior selection of the optimum scale for transit
detection, and 2) a period search in that selected wavelet transformation. The
detrending of the light curves are based on Fourier filtering or a discrete
wavelet transformation. TRUFAS requires the presence of at least 3 transit
events in the data. Results: The proposed algorithm is shown to identify
reliably and quickly the transits that had been included in a standard set of
999 light curves that simulate CoRoT data. Variations in the pre-processing of
the light curves and in the selection of the scale of the wavelet transform
have only little effect on TRUFAS' results. Conclusions: TRUFAS is a robust and
quick transit detection algorithm, especially well suited for the analysis of
very large volumes of data from space or ground-based experiments, with long
enough durations for the target-planets to produce multiple transit events.Comment: 9 pages, 10 figures, accepted by A&
Oscillations in the Sun with SONG: Setting the scale for asteroseismic investigations
Context. We present the first high-cadence multi-wavelength radial-velocity
observations of the Sun-as-a-star, carried out during 57 consecutive days using
the stellar \'echelle spectrograph at the Hertzsprung SONG Telescope operating
at the Teide Observatory. Aims. The aim was to produce a high-quality data set
and reference values for the global helioseismic parameters {\nu_{max}}, and
{\Delta \nu} of the solar p-modes using the SONG instrument. The obtained data
set or the inferred values should then be used when the scaling relations are
applied to other stars showing solar-like oscillations which are observed with
SONG or similar instruments. Methods. We used different approaches to analyse
the power spectrum of the time series to determine {\nu_{max}}; simple Gaussian
fitting and heavy smoothing of the power spectrum. {\Delta\nu} was determined
using the method of autocorrelation of the power spectrum. The amplitude per
radial mode was determined using the method described in Kjeldsen et al.
(2008). Results. We found the following values for the solar oscillations using
the SONG spectrograph: {\nu_{max}} = 3141 {\pm} 12 {\mu}Hz, {\Delta\nu} =
134.98 {\pm} 0.04 {\mu}Hz and an average amplitude of the strongest radial
modes of 16.6 {\pm} 0.4 cm/s. These values are consistent with previous
measurements with other techniques.Comment: 5 pages, 5 figures, letter accepted for A&
Interactions between sub-10 nm iron and cerium oxide nanoparticles and 3T3 fibroblasts : the role of the coating and aggregation state
Recent nanotoxicity studies revealed that the physico-chemical
characteristics of engineered nanomaterials play an important role in the
interactions with living cells. Here, we report on the toxicity and uptake of
the cerium and iron oxide sub-10 nm nanoparticles by NIH/3T3 mouse fibroblasts.
Coating strategies include low-molecular weight ligands (citric acid) and
polymers (poly(acrylic acid), MW = 2000 g mol-1). Electrostatically adsorbed on
the surfaces, the organic moieties provide a negatively charged coating in
physiological conditions. We find that most particles were biocompatible, as
exposed cells remained 100% viable relative to controls. Only the bare and the
citrate-coated nanoceria exhibit a slight decrease of the mitochondrial
activity for cerium concentrations above 5 mM (equivalent to 0.8 g L-1). We
also observe that the citrate-coated particles are internalized by the cells in
large amounts, typically 250 pg per cell after a 24 h incubation for iron
oxide. In contrast, the polymer-coated particles are taken up at much lower
rates (< 30 pg per cell). The strong uptake shown by the citrate-coated
particles is related to the destabilization of the dispersions in the cell
culture medium and their sedimentation down to the cell membranes. In
conclusion, we show that the uptake of nanomaterials by living cells depends on
the coating of the particles and on its ability to preserve the colloidal
nature of the dispersions.Comment: 9 figures, 2 table
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