622 research outputs found
Optimal Pooling in Claims Resolution Facilities
A class of nonlinear stochastic processes satysfying a "Lipschitz-type strip condition" and supplied by a linear output equation, is considered. Robust asymptotic (high-gain) state estimation for nonlinear stochastic processes via differential neural networks is discussed. A new type learning law for the weight dynamics is suggested. By a stochastic Lyapunov-like analysis (with Ito formula implementation), the stability conditions for the state estimation error as well as for the neural network weights are established. The upper bound for this error is derived. The numerical example, dealing with "module"-type nonlinearities, illustrates the effectiveness of the suggested approach
Baryon-Baryon Interactions from Lattice QCD
We report on new attempt to investigate baryon-baryon interactions in lattice
QCD. From the Bethe-Salpeter (BS) wave function, we have successfully extracted
the nucleon-nucleon () potentials in quenched QCD simulations, which
reproduce qualitative features of modern potentials. The method has been
extended to obtain the tensor potential as well as the central potential and
also applied to the hyperon-nucleon () interactions, in both quenched and
full QCD.Comment: 6 pages, 10 figures, A plenary talk given at the 5-th International
Conference on Quark and Nuclear Physics, Beijing, September 21-26, 200
A cross-sectional study on prevalence and predictors of burnout among a sample of pharmacists employed in pharmacies in Central Italy
Burnout is defined as an occupational phenomenon linked to chronic workplace stress that has not been successfully managed and included among the factors influencing health status or contact with health services. Although several studies were performed for assessing this phenomenon, there is a lack of data on the prevalence of burnout and associated predictors, due to different definitions of the syndrome and heterogeneity of assessment methods. One of the well-known evidences on burnout is related to the highest risk professions, which include policemen, firemen, teachers, psychologists, medical students, nurses, physicians, and other health professionals, such as pharmacists. Objective. The aims of the present study were to (1) assess the occurrence of burnout syndrome among a sample of pharmacists employed in public and private pharmacies located in Rome province (Latium Region; central Italy); (2) evaluate the role of some potential predictors for the development of the syndrome. Materials and Methods. A questionnaire elaborated ad hoc was administered online to 2,000 members of the Association of Professional Pharmacists of Rome and its province and employed in public or private pharmacies. The questionnaire included the 14-item Shirom-Melamed Burnout Measure (SMBM) tool and questions on demographic characteristics and working conditions. Results. Physical exhaustion was the burnout dimension with the highest score; besides, approximately 11% of the studied pharmacists were categorized as having clinically relevant burnout levels (≥4.40). Several of the investigated variables significantly influenced the single burnout dimensions at the univariate analyses; multivariate analyses demonstrated that alcohol consumption and workplace location have a significant independent role on the overall SMBM index, while working time significantly influences clinically relevant burnout level. Conclusions. The results revealed that pharmacists are at risk of burnout, and thus, it is necessary to perform specific preventive intervention for managing this occupational threat
Spin-Orbit Force from Lattice QCD
We present a first attempt to determine nucleon-nucleon potentials in the
parity-odd sector, which appear in 1P1, 3P0, 3P1, 3P2-3F2 channels, in Nf=2
lattice QCD simulations. These potentials are constructed from the
Nambu-Bethe-Salpeter wave functions for J^P=0^-, 1^- and 2^-, which correspond
to A1^-, T1^- and T2^- + E^- representation of the cubic group, respectively.
We have found a large and attractive spin-orbit potential VLS(r) in the
isospin-triplet channel, which is qualitatively consistent with the
phenomenological determination from the experimental scattering phase shifts.
The potentials obtained from lattice QCD are used to calculate the scattering
phase shifts in 1P1, 3P0, 3P1 and 3P2-3F2 channels. The strong attractive
spin-orbit force and a weak repulsive central force in spin-triplet P-wave
channels lead to an attraction in the 3P2 channel, which is related to the
P-wave neutron paring in neutron stars.Comment: 14 pages, 5 figures, Physics Letters B published versio
Coupled channel approach to strangeness S = -2 baryon-bayron interactions in Lattice QCD
The baryon-baryon interactions with strangeness S = -2 with the flavor SU(3)
breaking are calculated for the first time by using the HAL QCD method extended
to coupled channel system in lattice QCD. The potential matrices are extracted
from the Nambu-Bethe-Salpeter wave functions obtained by the 2+1 flavor gauge
configurations of CP-PACS/JLQCD Collaborations with a physical volume of 1.93
fm cubed and with m_pi/m_K = 0.96, 0.90, 0.86. The spatial structure and the
quark mass dependence of the potential matrix in the baryon basis and in the
SU(3) basis are investigated.Comment: 17 pages, 15 figure
Kaon-Nucleon potential from lattice QCD
We study the KN interactions in the I(J^{\pi})=0(1/2^-) and 1(1/2^-) channels
and associated exotic state \Theta^+ from 2+1 flavor full lattice QCD
simulation for relatively heavy quark mass corresponding to m_{\pi}=871 MeV.
The s-wave KN potentials are obtained from the Bethe-Salpeter wave function by
using the method recently developed by HAL QCD (Hadrons to Atomic nuclei from
Lattice QCD) Collaboration. Potentials in both channels reveal short range
repulsions: Strength of the repulsion is stronger in the I=1 potential, which
is consistent with the prediction of the Tomozawa-Weinberg term. The I=0
potential is found to have attractive well at mid range. From these potentials,
the scattering phase shifts are calculated and compared with the
experimental data.Comment: Talk given at 19th International IUPAP Conference on Few-Body
Problems in Physics (fb19), Bonn, Germany, 30 Aug - 5 Sep 200
Colossal electroresistance and colossal magnetoresistive step in paramagnetic insulating phase of single crystalline bilayered manganite(LaPr)SrMnO
We report a significant decrease in the low-temperature resistance induced by
the application of an electric current on the -plane in the paramagnetic
insulating (PMI) state of
(LaPr)SrMnO. A colossal
electroresistance effect attaining -95% is observed at lower temperatures. A
colossal magnetoresistive step appears near 5T at low temperatures below 10K,
accompanied by an ultrasharp width of the insulator-metal transition. Injection
of higher currents to the crystal causes a disappearance of the steplike
transition. These findings have a close relationship with the presence of the
short-range charge-ordered clusters pinned within the PMI matrix of the crystal
studied.Comment: 4 pages 3 figure
Mirage in Temporal Correlation functions for Baryon-Baryon Interactions in Lattice QCD
Single state saturation of the temporal correlation function is a key
condition to extract physical observables such as energies and matrix elements
of hadrons from lattice QCD simulations. A method commonly employed to check
the saturation is to seek for a plateau of the observables for large Euclidean
time. Identifying the plateau in the cases having nearby states, however, is
non-trivial and one may even be misled by a fake plateau. Such a situation
takes place typically for the system with two or more baryons. In this study,
we demonstrate explicitly the danger from a possible fake plateau in the
temporal correlation functions mainly for two baryons ( and ), and
three and four baryons ( and as well, employing
(2+1)-flavor lattice QCD at GeV on four lattice volumes with
2.9, 3.6, 4.3 and 5.8 fm. Caution is given for drawing conclusion on the
bound , and systems only based on the temporal correlation
functions.Comment: 32 pages, 13 figures, minor corrections, published version, typos
correcte
Nucleon-nucleon interactions via Lattice QCD: Methodology --HAL QCD approach to extract hadronic interactions in lattice QCD--
We review the potential method in lattice QCD, which has recently been
proposed to extract nucleon-nucleon interactions via numerical simulations. We
focus on the methodology of this approach by emphasizing the strategy of the
potential method, the theoretical foundation behind it, and special numerical
techniques. We compare the potential method with the standard finite volume
method in lattice QCD, in order to make pros and cons of the approach clear. We
also present several numerical results for the nucleon-nucleon potentials.Comment: 12 pages, 10 figure
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