515 research outputs found

    New "Square Root" Model of Lepton Family Cyclic Symmetry

    Full text link
    Following the newly formulated notion of form invariance of the neutrino mass matrix, a complete model of leptons is constructed. It is based on a specific unitary 3 X 3 matrix U in family space, such that U^2 is the simple discrete symmetry nu_e to -nu_e, nu_mu to nu_tau. Thus U also generates the cyclic group Z_4. The charged-lepton mass matrix is nearly diagonal while the neutrino mass matrix is of the form suitable for explaining maximal (large) mixing in atmospheric (solar) neutrino oscillations in the context of three nearly degenerate neutrino masses. Observable lepton flavor violation is predicted. Quarks may be treated in the same way as the charged leptons.Comment: 10 pages, no figur

    The Importance of Project Manager’s Soft Competence on IT Project Success: An Exploratory Study in the Banking Context

    Get PDF
    The high failure rate of IT projects has continued for more than three decades. The premise of this research is that IT project success depends not only on technical skills and knowledge (such as in civil engineering) but also on the “soft” aspects such as project manager’s competence to effectively interact with various stakeholders and align the project with their expectations. This research examines the most critical IT project manager’s soft competences required for IT project success in the banking industry. The findings from multiple case studies and survey analysis will have significant implications for both research and practice in the field of IT project success, IT investment and development of IT professionals, especially in the banking sector. (Initial findings from the first case study interviews are shown in Appendix 1.

    The influences of transformational leadership on employee employability: Evidence from China

    Get PDF
    Purpose The purpose of this paper is to examine the mediating role of job characteristics and social exchange in transformational leadership (TFL) and employability relationship. Design/methodology/approach The sample is composed of 760 participants employed in Yangtze Delta and Pearl River Delta in China. The participants have worked under their line manager for more than one year. In order to better prevent data from possible common method bias, two waves of surveys (in 2014) on a stratified sample, included a mix of industries, such as construction, manufacturing, finance, insurance and communications, were used to investigate the proposed relationship between TFL, job characteristics, social exchange and employability. Findings The research has empirically tested the relationship between TFL and employability. While previous research has analyzed the relationship between them, the authors have enriched existing literature by exploring the mediating factors and illustrating the importance of indirect effects. Besides the direct effect, the results of this study showed that TFL could also improve employees’ employability through job demands, skill discretion, decision authority, perceived organizational support and team–member exchange, but not leader–member exchange. Originality/value The study opens up a debate around the employability of employees as it stands apart from the performance measurement. The authors believe that this new mediating model can provide an insight into complex mechanisms of employability enhancement from the perspective of leader development

    A guide to northern sea cucumbers: The biology and management of Cucumaria frondosa

    Get PDF
    This document synthesising knowledge on the northern sea cucumber Cucumaria frondosa was prepared for all stakeholders, including industry participants, government scientists, policymakers, and academic researchers. Its aim is to highlight the uniqueness of this marine resource to guide the industry forward and to emphasize areas that deserve further investigation. Available data from eastern and northern Canada, eastern United States of America, Greenland, northern Europe and the Russian Federation are presented. Topics covered include the taxonomy, distribution, biology, and ecology of the species, the natural threats it faces, the current harvesting, processing and marketing practices, and the prospects for aquaculture development. Relying on a knowledge base gathered over more than 40 years, this contribution compares C. frondosa with other common commercial species of sea cucumbers to tease out the major aspects that set it apart. A final section provides a number of key recommendations for its management and conservation

    Sudden switch of generalized Lieb-Robinson velocity in a transverse field Ising spin chain

    Full text link
    The Lieb-Robinson theorem states that the speed at which the correlations between two distant nodes in a spin network can be built through local interactions has an upper bound, which is called the Lieb-Robinson velocity. Our central aim is to demonstrate how to observe the Lieb-Robinson velocity in an Ising spin chain with a strong transverse field. We adopt and compare four correlation measures for characterizing different types of correlations, which include correlation function, mutual information, quantum discord, and entanglement of formation. We prove that one of correlation functions shows a special behavior depending on the parity of the spin number. All the information-theoretical correlation measures demonstrate the existence of the Lieb-Robinson velocity. In particular, we find that there is a sudden switch of the Lieb-Robinson speed with the increasing of the number of spin

    Relic neutrino masses and the highest energy cosmic rays

    Get PDF
    We consider the possibility that a large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic neutrinos. We compare the observed ultrahigh energy cosmic ray spectrum with the one predicted in the above Z-burst scenario and determine the required mass of the heaviest relic neutrino as well as the necessary ultrahigh energy cosmic neutrino flux via a maximum likelihood analysis. We show that the value of the neutrino mass obtained in this way is fairly robust against variations in presently unknown quantities, like the amount of neutrino clustering, the universal radio background, and the extragalactic magnetic field, within their anticipated uncertainties. Much stronger systematics arises from different possible assumptions about the diffuse background of ordinary cosmic rays from unresolved astrophysical sources. In the most plausible case that these ordinary cosmic rays are protons of extragalactic origin, one is lead to a required neutrino mass in the range 0.08 eV - 1.3 eV at the 68 % confidence level. This range narrows down considerably if a particular universal radio background is assumed, e.g. to 0.08 eV - 0.40 eV for a large one. The required flux of ultrahigh energy cosmic neutrinos near the resonant energy should be detected in the near future by AMANDA, RICE, and the Pierre Auger Observatory, otherwise the Z-burst scenario will be ruled out.Comment: 19 pages, 22 figures, REVTeX

    Fluctuations, dissipation and the dynamical Casimir effect

    Full text link
    Vacuum fluctuations provide a fundamental source of dissipation for systems coupled to quantum fields by radiation pressure. In the dynamical Casimir effect, accelerating neutral bodies in free space give rise to the emission of real photons while experiencing a damping force which plays the role of a radiation reaction force. Analog models where non-stationary conditions for the electromagnetic field simulate the presence of moving plates are currently under experimental investigation. A dissipative force might also appear in the case of uniform relative motion between two bodies, thus leading to a new kind of friction mechanism without mechanical contact. In this paper, we review recent advances on the dynamical Casimir and non-contact friction effects, highlighting their common physical origin.Comment: 39 pages, 4 figures. Review paper to appear in Lecture Notes in Physics, Volume on Casimir Physics, edited by Diego Dalvit, Peter Milonni, David Roberts, and Felipe da Rosa. Minor changes, a reference adde

    Magnetic Reconnection in Extreme Astrophysical Environments

    Full text link
    Magnetic reconnection is a basic plasma process of dramatic rearrangement of magnetic topology, often leading to a violent release of magnetic energy. It is important in magnetic fusion and in space and solar physics --- areas that have so far provided the context for most of reconnection research. Importantly, these environments consist just of electrons and ions and the dissipated energy always stays with the plasma. In contrast, in this paper I introduce a new direction of research, motivated by several important problems in high-energy astrophysics --- reconnection in high energy density (HED) radiative plasmas, where radiation pressure and radiative cooling become dominant factors in the pressure and energy balance. I identify the key processes distinguishing HED reconnection: special-relativistic effects; radiative effects (radiative cooling, radiation pressure, and Compton resistivity); and, at the most extreme end, QED effects, including pair creation. I then discuss the main astrophysical applications --- situations with magnetar-strength fields (exceeding the quantum critical field of about 4 x 10^13 G): giant SGR flares and magnetically-powered central engines and jets of GRBs. Here, magnetic energy density is so high that its dissipation heats the plasma to MeV temperatures. Electron-positron pairs are then copiously produced, making the reconnection layer highly collisional and dressing it in a thick pair coat that traps radiation. The pressure is dominated by radiation and pairs. Yet, radiation diffusion across the layer may be faster than the global Alfv\'en transit time; then, radiative cooling governs the thermodynamics and reconnection becomes a radiative transfer problem, greatly affected by the ultra-strong magnetic field. This overall picture is very different from our traditional picture of reconnection and thus represents a new frontier in reconnection research.Comment: Accepted to Space Science Reviews (special issue on magnetic reconnection). Article is based on an invited review talk at the Yosemite-2010 Workshop on Magnetic Reconnection (Yosemite NP, CA, USA; February 8-12, 2010). 30 pages, no figure

    How important is the context of an adolescent's first alcoholic drink? Evidence that parental provision may reduce later heavy episodic drinking

    Get PDF
    Objective: This study examined the extent to which a retrospective measure of parental provision of the first alcoholic beverage was related to current heavy episodic drinking and current responsible drinking practices. Sample: 608 14- to 17-year-olds from the 2007 Australian National Drug Strategy Household Survey. Measures: Source of first alcoholic beverage (friends/parents/others), source of current alcohol, age of onset of alcohol use, current responsible drinking practices, and proportion of current friends who drink. Results: Binary logistic and multiple regression procedures revealed that parental provision of an adolescent's first alcoholic beverage predicted lower current heavy episodic drinking, and responsible drinking mediated this association. Discussion: The results suggested that for adolescents who become alcohol users, parental provision of the first drink may reduce subsequent alcohol-related risks compared to introduction to alcohol by friends and other sources. Alcohol-related risks remain significant for adolescents who consume alcohol, independent of who is the provider. Copyright (C) 2012 S. Karger AG, Base
    • 

    corecore