828 research outputs found

    CLEAR Space Weather Center of Excellence: All-Clear Solar Energetic Particle Prediction

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    The CLEAR Space Weather Center of Excellence (CLEAR center) is a five year project that is funded by the NASA Space Weather Center of Excellence program. The CLEAR center will build a comprehensive prediction framework for solar energetic particles (SEPs) focusing on the timely and accurate prediction of low radiation periods (``all clear forecast") and the occurrence and characteristics of elevated periods. This will be accomplished by integrating empirical, first-principles based and machine learning (ML)-trained prediction models. In this paper, the motivation, overview, and tools of the CLEAR center will be discussed

    Spin-orbit and orbit-orbit strengths for radioactive neutron-rich doubly magic nucleus 132^{132}Sn in relativistic mean field theory

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    Relativistic mean field (RMF) theory is applied to investigate the properties of the radioactive neutron-rich doubly magic nucleus 132^{132}Sn and the corresponding isotopes and isotones. The two-neutron and two-proton separation energies are well reproduced by the RMF theory. In particular, the RMF results agree with the experimental single-particle spectrum in 132^{132}Sn as well as the Nilsson spin-orbit parameter CC and orbit-orbit parameter DD thus extracted, but remarkably differ from the traditional Nilsson parameters. Furthermore, the present results provide a guideline for the isospin dependence of the Nilsson parameters.Comment: 4 pages, 4 figures, Phys. Rev. C in pres

    Labor Relations Conflict in the Workplace: Scale Development, Consequences and Solutions

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    Because the goals of employers and employees are often incompatible, conflicts are inevitable and an essential part of organizational life. The three studies reported in this paper addressed the issues of identifying the dimensions of workplace conflicts within organizations, exploring the consequences of conflicts, and finding appropriate methods of conflict resolution. The first study identified and developed three dimensions of labor relations conflict, including interest-based, rights-based, and emotion-based conflicts. The second study explored two sets of individual outcomes of labor relations conflicts and found labor relations conflicts had a negative effect on employee job satisfaction and affective commitment and positive effects on employee turnover intention and counterproductive work behavior. The third study tested the effectiveness of partnership practices as an alternative method of resolving labor relations conflicts. Suggestions are offered for future research on the labor relations conflict dimensions as well as its outcomes and solutions introduced in these studies

    Stochastic scheduling of autonomous mobile robots at hospitals

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    The outbreak of the New Coronavirus has significantly increased the vulnerability of medical staff. This paper addresses the safety and stress relief of medical personnel by proposing a solution to the scheduling problem of autonomous mobile robots (AMRs) in a stochastic environment. Considering the stochastic nature of travel and service times for AMRs affected by the surrounding environment, the routes of AMRs are planned to minimize the daily cost of the hospital (including the AMR fixed cost, penalty cost of violating the time window, and transportation cost). To efficiently generate high-quality solutions, we identify several properties and incorporate them into an improved Tabu Search (I-TS) algorithm for problem-solving. Experimental evaluations demonstrate that the I-TS algorithm outperforms existing methods by producing higher-quality solutions. By leveraging the characteristics of medical request environments, we intelligently allocate an appropriate number of AMRs to efficiently provide services, resulting in substantial cost reductions for hospitals and enhanced utilization of medical resources. These findings confirm the effectiveness of the proposed stochastic programming model in determining the optimal number of AMRs and their corresponding service routes across various environmental settings

    Microscopic and self-consistent description for neutron halo in deformed nuclei

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    A deformed relativistic Hartree-Bogoliubov theory in continuum has been developed for the study of neutron halos in deformed nuclei and the halo phenomenon in deformed weakly bound nuclei is investigated. Magnesium and neon isotopes are studied and some results are presented for the deformed neutron-rich and weakly bound nuclei 44Mg and 36Ne. The core of the former nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.Comment: 7 pages, 2 figures; invited talk at the XXXV Brazilian Workshop on Nuclear Physics, Sep 2-6, 2012, Maresias, Brazi

    Halos in a deformed Relativistic Hartree-Bogoliubov theory in continuum

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    In this contribution we present some recent results about neutron halos in deformed nuclei. A deformed relativistic Hartree-Bogoliubov theory in continuum has been developed and the halo phenomenon in deformed weakly bound nuclei is investigated. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nuclei 42Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.Comment: 6 pages, 2 figures; invited talk at the 2nd Int. Conf. on Nuclear Structure & Dynamics (NSD12), Opatija, Croatia, 9-13 July 201

    Application of the Monte Carlo Method in Modeling Transport and Acceleration of Solar Energetic Particles

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    The need for quantitative characterization of the solar energetic particle (SEP) dynamics goes beyond being an academic discipline only. It has numerous practical implications related to human activity in space. The terrestrial magnetic field shields the International Space Station (ISS) and most uncrewed missions from exposure to SEP radiation. However, extreme SEP events with hard energy spectra are particularly rich in hundreds of MeV to several GeV protons that can reach the altitudes of the Low Earth Orbit (LEO). These protons have a high penetrating capability, thus producing significant radiation hazards for human spaceflight. SEPs also have a significant effect on the atmosphere. Sudden ionization of the upper atmosphere at high latitudes that occurs during polar cap absorption (PCA) events can block high frequency (HF) communication for hours, affecting communication with aircraft on intercontinental high-altitude flights. Another effect of SEPs in the atmosphere is creating NOx molecules in the upper atmosphere that can deplete the atmospheric ozone population. The paper also presents an analysis of (1) how various pitch angle diffusion coefficient approximations affect the properties of the simulated SEPs population and (2) discusses how pitch angle scattering when SEPs are beyond 1 AU affects a SEP event decay phase at the Earth's orbit
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