31,635 research outputs found

    Constant-temperature molecular-dynamics algorithms for mixed hard-core/continuous potentials

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    We present a set of second-order, time-reversible algorithms for the isothermal (NVT) molecular-dynamics (MD) simulation of systems with mixed hard-core/continuous potentials. The methods are generated by combining real-time Nose' thermostats with our previously developed Collision Verlet algorithm [Mol. Phys. 98, 309 (1999)] for constant energy MD simulation of such systems. In all we present 5 methods, one based on the Nose'-Hoover [Phys. Rev. A 31, 1695 (1985)] equations of motion and four based on the Nose'-Poincare' [J.Comp.Phys., 151 114 (1999)] real-time formulation of Nose' dynamics. The methods are tested using a system of hard spheres with attractive tails and all correctly reproduce a canonical distribution of instantaneous temperature. The Nose'-Hoover based method and two of the Nose'-Poincare' methods are shown to have good energy conservation in long simulations.Comment: 9 pages, 5 figure

    Impact of the Neutrino Magnetic Moment on the Neutrino Fluxes and the Electron Fraction in core-collapse Supernovae

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    We explore the effect of the neutrino magnetic moment on neutrino scattering with matter in a core-collapse Supernova. We study the impact both on the neutrino fluxes and on the electron fraction. We find that sizeable modifications require very large magnetic moments both for Dirac and Majorana neutrinos.Comment: 7 pages, 6 figure

    Effects of the triaxial deformation and pairing correlation on the proton emitter 145Tm

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    The ground-state properties of the recent reported proton emitter 145Tm have been studied within the axially or triaxially deformed relativistic mean field (RMF) approaches, in which the pairing correlation is taken into account by the BCS-method with a constant pairing gap. It is found that triaxiality and pairing correlations play important roles in reproducing the experimental one proton separation energy. The single-particle level, the proton emission orbit, the deformation parameters beta = 0.22 and gamma = 28.98 and the corresponding spectroscopic factor for 145Tm in the triaxial RMF calculation are given as well.Comment: 17 pages, 7 figures and 1 table. accepted by Physical Review

    Evaluation of the Abidjan lagoon pollution

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    The Abidjan lagoon pollution evaluation via the physicochemical and biochemical characteristics of effluents pouring in it, in order to take decision concerning the installation of a treatment station was reported. All samples of effluents studied contain high quantity of organic and mineral pollutants except for samples from a hospital (effluent II). However, the analysis of the ratios COD/BOD of the different effluents showed that the corresponding wastewaters have a domestic character and are therefore easily biodegradable

    Loss Guided Activation for Action Recognition in Still Images

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    One significant problem of deep-learning based human action recognition is that it can be easily misled by the presence of irrelevant objects or backgrounds. Existing methods commonly address this problem by employing bounding boxes on the target humans as part of the input, in both training and testing stages. This requirement of bounding boxes as part of the input is needed to enable the methods to ignore irrelevant contexts and extract only human features. However, we consider this solution is inefficient, since the bounding boxes might not be available. Hence, instead of using a person bounding box as an input, we introduce a human-mask loss to automatically guide the activations of the feature maps to the target human who is performing the action, and hence suppress the activations of misleading contexts. We propose a multi-task deep learning method that jointly predicts the human action class and human location heatmap. Extensive experiments demonstrate our approach is more robust compared to the baseline methods under the presence of irrelevant misleading contexts. Our method achieves 94.06\% and 40.65\% (in terms of mAP) on Stanford40 and MPII dataset respectively, which are 3.14\% and 12.6\% relative improvements over the best results reported in the literature, and thus set new state-of-the-art results. Additionally, unlike some existing methods, we eliminate the requirement of using a person bounding box as an input during testing.Comment: Accepted to appear in ACCV 201

    Performance Comparison Between FEDERICA Hand and LARM Hand

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    This paper describes two robotic hands that have been developed at University Federico II of Naples and at the University of Cassino. FEDERICA Hand and LARM Hand are described in terms of design and operational features. In particular, careful attention is paid to the differences between the above-mentioned hands in terms of transmission systems. FEDERICA Hand uses tendons and pulleys to drive phalanxes, while LARM Hand uses cross four-bar linkages. Results of experimental tests are reported to show how key design issues affect each robotic hand’s performance

    New bounds on the neutrino magnetic moment from the plasma induced neutrino chirality flip in a supernova

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    The neutrino chirality-flip process under the conditions of the supernova core is investigated in detail with the plasma polarization effects in the photon propagator taken into account, in a more consistent way than in earlier publications. It is shown in part that the contribution of the proton fraction of plasma is essential. New upper bounds on the neutrino magnetic moment are obtained: mu_nu < (0.5 - 1.1) 10^{-12} mu_B from the limit on the supernova core luminosity for nu_R emission, and mu_nu < (0.4 - 0.6) 10^{-12} mu_B from the limit on the averaged time of the neutrino spin-flip. The best upper bound on the neutrino magnetic moment from SN1987A is improved by the factor of 3 to 7.Comment: 19 pages, LaTeX, 7 EPS figures, submitted to Journal of Cosmology and Astroparticle Physic

    Evaluation of the Abidjan lagoon pollution

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    The Abidjan lagoon pollution evaluation via the physicochemical and biochemical characteristics of effluents pouring in it, in order to take decision concerning the installation of a treatment station was reported. All samples of effluents studied contain high quantity of organic and mineral pollutants except for samples from a hospital (effluent II). However, the analysis of the ratios COD/BOD of the different effluents showed that the corresponding wastewaters have a domestic character and are therefore easily biodegradable. Journal of Applied Sciences and Environmental Management Vol. 10(3) 2006: 175-18

    Core Polarization and Tensor Coupling Effects on Magnetic Moments of Hypernuclei

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    The effects of core polarization and tensor coupling on the magnetic moments in Λ13^{13}_\LambdaC, Λ17^{17}_\LambdaO, and Λ41^{41}_\LambdaCa Λ\Lambda-hypernuclei are studied in the Dirac equation with scalar, vector and tensor potentials. It is found that the effect of core polarization on the magnetic moments is suppressed by Λ\Lambda tensor coupling. The Λ\Lambda tensor potential reduces the spin-orbit splitting of pΛp_\Lambda states considerably. However, almost the same magnetic moments are obtained using the hyperon wave function obtained via the Dirac equation either with or without the Λ\Lambda tensor potential in the electromagnetic current vertex. The deviations of magnetic moments for pΛp_\Lambda states from the Schmidt values are found to increase with nuclear mass number.Comment: 10 pages, 2 figures, 2 table
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