969 research outputs found

    Fiscal output data produce versatile graphic-numeric charts

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    Refined computerized plotting system produces low-cost graphic-numeric charts that illustrate fiscal data on monthly incremental or cumulative basis, or both. Output is in the form of hard copy or microfilm, or visual-aid transparencies prepared from hard copy for rapid management status presentations

    Bouncing Neutrons and the Neutron Centrifuge

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    The recent observation of the quantum state of the neutron bouncing freely under gravity allows some novel experiments. A method of purifying the ground state is given, and possible applications to the measurement of the electric dipole moment of the neutron and the short distance behaviour of gravity are discussed.Comment: 7 pages, 7 figure

    Neutrino masses and mixing parameters in a left-right model with mirror fermions

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    In this work we consider a left-right model containing mirror fermions with gauge group SU(3)C⊗SU(2)L⊗SU(2)R⊗U(1)Yâ€Č_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}. The model has several free parameters which here we have calculated by using the recent values for the squared-neutrino mass differences. Lower bound for the mirror vacuum expectation value helped us to obtain crude estimations for some of these parameters. Also we estimate the order of magnitude of the masses of the standard and mirror neutrinos.Comment: 13 pages, version submitted to European Physical Journal

    New Discrete Basis for Nuclear Structure Studies

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    A complete discrete set of spherical single-particle wave functions for studies of weakly-bound many-body systems is proposed. The new basis is obtained by means of a local-scale point transformation of the spherical harmonic oscillator wave functions. Unlike the harmonic oscillator states, the new wave functions decay exponentially at large distances. Using the new basis, characteristics of weakly-bound orbitals are analyzed and the ground state properties of some spherical doubly-magic nuclei are studied. The basis of the transformed harmonic oscillator is a significant improvement over the harmonic oscillator basis, especially in studies of exotic nuclei where the coupling to the particle continuum is important.Comment: 13 pages, RevTex, 6 p.s. figures, submitted to Phys. Rev.

    Gamow Shell Model Description of Weakly Bound Nuclei and Unbound Nuclear States

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    We present the study of weakly bound, neutron-rich nuclei using the nuclear shell model employing the complex Berggren ensemble representing the bound single-particle states, unbound Gamow states, and the non-resonant continuum. In the proposed Gamow Shell Model, the Hamiltonian consists of a one-body finite depth (Woods-Saxon) potential and a residual two-body interaction. We discuss the basic ingredients of the Gamow Shell Model. The formalism is illustrated by calculations involving {\it several} valence neutrons outside the double-magic core: 6−10^{6-10}He and 18−22^{18-22}O.Comment: 19 pages, 20 encapsulated PostScript figure

    Combining spatial and parametric working memory in a dynamic neural field model

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    We present a novel dynamic neural field model consisting of two coupled fields of Amari-type which supports the existence of localized activity patterns or “bumps” with a continuum of amplitudes. Bump solutions have been used in the past to model spatial working memory. We apply the model to explain input-specific persistent activity that increases monotonically with the time integral of the input (parametric working memory). In numerical simulations of a multi-item memory task, we show that the model robustly memorizes the strength and/or duration of inputs. Moreover, and important for adaptive behavior in dynamic environments, the memory strength can be changed at any time by new behaviorally relevant information. A direct comparison of model behaviors shows that the 2-field model does not suffer the problems of the classical Amari model when the inputs are presented sequentially as opposed to simultaneously

    Hestenes' Tetrad and Spin Connections

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    Defining a spin connection is necessary for formulating Dirac's bispinor equation in a curved space-time. Hestenes has shown that a bispinor field is equivalent to an orthonormal tetrad of vector fields together with a complex scalar field. In this paper, we show that using Hestenes' tetrad for the spin connection in a Riemannian space-time leads to a Yang-Mills formulation of the Dirac Lagrangian in which the bispinor field is mapped to a set of Yang-Mills gauge potentials and a complex scalar field. This result was previously proved for a Minkowski space-time using Fierz identities. As an application we derive several different non-Riemannian spin connections found in the literature directly from an arbitrary linear connection acting on Hestenes' tetrad and scalar fields. We also derive spin connections for which Dirac's bispinor equation is form invariant. Previous work has not considered form invariance of the Dirac equation as a criterion for defining a general spin connection

    GeantV: Results from the prototype of concurrent vector particle transport simulation in HEP

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    Full detector simulation was among the largest CPU consumer in all CERN experiment software stacks for the first two runs of the Large Hadron Collider (LHC). In the early 2010's, the projections were that simulation demands would scale linearly with luminosity increase, compensated only partially by an increase of computing resources. The extension of fast simulation approaches to more use cases, covering a larger fraction of the simulation budget, is only part of the solution due to intrinsic precision limitations. The remainder corresponds to speeding-up the simulation software by several factors, which is out of reach using simple optimizations on the current code base. In this context, the GeantV R&D project was launched, aiming to redesign the legacy particle transport codes in order to make them benefit from fine-grained parallelism features such as vectorization, but also from increased code and data locality. This paper presents extensively the results and achievements of this R&D, as well as the conclusions and lessons learnt from the beta prototype.Comment: 34 pages, 26 figures, 24 table

    Revisiting mortality deceleration patterns in a gamma-Gompertz-Makeham framework

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    We calculate life-table aging rates (LARs) for overall mortality by estimating a gamma-Gompertz-Makeham (G GM) model and taking advantage of LAR’s parametric representation by Vaupel and Zhang [34]. For selected HMD countries, we study how the evolution of estimated LAR patterns could explain observed 1) longevity dynamics, and 2) mortality improvement or deterioration at different ages. Surprisingly, the age of mortality deceleration x showed almost no correlation with a number of longevity measures apart from e0. In addition, as mortality concentrates at older ages with time, its characteristic bell-shaped pattern becomes more pronounced. Moreover, in a GGM framework, we identify the impact of senescent mortality on shape of the rate of population aging. We also find evidence for a strong relationship between x and the statistically significant curvilinear changes in the evolution of e0 over time. Finally, model-based LARs appear to be consistent with point b) of the “heterogeneity hypothesis” [12]: mortality deceleration, due to selection effects, should shift to older ages as the level of total adult mortality declines
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