124 research outputs found

    Nuclear isospin asymmetry in α\alpha decays of heavy nuclei

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    The effects of nuclear isospin asymmetry on α\alpha decay lifetimes of heavy nuclei are investigated within various phenomenological models of nuclear potential for the α\alpha particle. We consider the widely used simple square well potential and Woods-Saxon potential, and modify them by including an isospin asymmetry term. We then suggest a model for the potential of the α\alpha particle motivated by a microscopic phenomenological approach of the Skyrme force model, which naturally introduce the isospin dependent form of the nuclear potential for the α\alpha particle. The empirical α\alpha decay lifetime formula of Viola and Seaborg is also modified to include isospin asymmetry effects. The obtained α\alpha decay half-lives are in good agreement with the experimental data and we find that including the nuclear isospin effects somehow improves the theoretical results for α\alpha decay half-lives. The implications of these results are discussed and the predictions on the α\alpha decay lifetimes of superheavy elements are also presented.Comment: 14 pages, 7 figures, 7 tables, Accepted by PRC 94, 024320 (2016

    The Effectiveness of Function-Based Interventions in Inclusive Classrooms of Elementary Schools

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    Both at-risk students and students with disabilities have been jeopardized with their continued placements in inclusive classrooms because of the ongoing challenging behaviors. The evidence-based practice to deal with challenging behaviors involves the implementation of functional behavior assessments (FBAs) and function-based interventions (FBIs) in school settings. The types of interventions in this starred paper are categorized as antecedent-based, consequence-based, and multi-component interventions. All twelve studies were conducted in elementary schools in the United States except for two studies (i.e., South Korea and Iceland). Participants ranged in the grade levels from kindergarten to sixth grade. The findings of these studies supported that the implementation of FBIs derived from information of FBAs resulted in decreasing challenging behaviors or increasing appropriate behaviors for at-risk students and students with disabilities in inclusive classrooms of elementary schools

    Chiral EFT calculation of neutrino reactions in warm neutron-rich matter

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    Neutrino scattering and absorption rates of relevance to supernovae and neutron star mergers are obtained from nuclear matter dynamical structure functions that encode many-body effects from nuclear mean fields and correlations. We employ nuclear interactions from chiral effective field theory to calculate the density, spin, isospin, and spin-isospin response functions of warm beta-equilibrium nuclear matter. We include corrections to the single-particle energies in the mean field approximation as well as vertex corrections resummed in the random phase approximation (RPA), including, for the first time, both direct and exchange diagrams. We find that correlations included through the RPA redistribute the strength of the response to higher energy for neutrino absorption and lower energy for antineutrino absorption. This tends to suppress the absorption rate of electron neutrinos across all relevant energy scales. In contrast, the inclusion of RPA correlations enhances the electron antineutrino absorption rate at low energy and supresses the rate at high energy. These effects are especially important at high-density and in the vicinity of the neutrino decoupling region. Implications for heavy element nucleosynthesis, electromagnetic signatures of compact object mergers, supernova dynamics, and neutrino detection from galactic supernovae are discussed briefly.Comment: 13 pages, 14 figure

    A HISTORICAL APPROACH TO SYPHILIS INFECTION IN KOREA

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    From the end of the 15th century, syphilis spread worldwide, posing a serious threat to public health. Venereal syphilis has been a major research topic, not only in clinical medicine but also in paleopathology, especially because it is a disease of questionable origin and of high prevalence until the discovery of antibiotics. Syphilis in history has been studied extensively in Europe and the Americas, though less so in Asia. In this review, based on extant historical documents and available paleopathological data, we pinpoint the introduction and trace the spread of venereal syphilis in Korea to the end of the 19th century. This review provides fundamental information that will be of great help to future research on pre-20th century syphilis in Korea

    Use of a folding model and in situ spectroscopic techniques for rational formulation development and stability testing of Monoclonal antibody therapeutics

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    Aggregation is a critical issue that hampers the development of monoclonal antibody therapeutics (Mabs). Traditionally, aggregation is considered a process in which native forms of proteins are transformed into an unstable highly associated form through an intermediate formation step. Here we describe the unfolding of an anti CD40 antibody using a folding model based on Lumry-Eyring nucleated polymerization (LENP) model. This model captures several experimental features of the thermal unfolding of this protein as studied by common in situ biophysical techniques such as circular dichroism, fluorescence spectroscopy and turbidity measurements. According to this model, the unfolding and aggregation of the anti CD40 antibody is determined by several distinct steps that include conformational change(s) to generate aggregation prone states, reversible oligomer formation, nucleation and growth as well as their kinetics and the formation of higher order assemblies/aggregates. Furthermore, the loss of monomer is controlled by both thermodynamic (equilibrium unfolding) and kinetic determinants of the unfolding process. This approach captures both of these rate-limiting steps. It can be concluded that this approach is sensitive to formulation conditions such as protein concentration, changes in buffer conditions, and temperature stress. The potential use of this approach in formulation development and stability testing of Mabs is discussed
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