877 research outputs found

    Neutrino Oscillations from Supersymmetry without R-parity - Its Implications on the Flavor Structure of the Theory

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    We discuss here some flavor structure aspects of the complete theory of supersymmetry without R-parity addressed from the perspective of fitting neutrino oscillation data based on the recent Super-Kamiokande result. The single-VEV parametrization of supersymmetry without R-parity is first reviewed, illustrating some important features not generally appreciated. For the flavor structure discussions, a naive, flavor model independent, analysis is presented, from which a few interesting things can be learned.Comment: 1+10 pages latex, no figure; Invited talk at NANP 99 conference, Dubna (Jun 28 - Jul 3) --- submission for the proceeding

    Single and Multiple Vortex Rings in Three-Dimensional Bose-Einstein Condensates: Existence, Stability and Dynamics

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    In the present work, we explore the existence, stability and dynamics of single and multiple vortex ring states that can arise in Bose-Einstein condensates. Earlier works have illustrated the bifurcation of such states, in the vicinity of the linear limit, for isotropic or anisotropic three-dimensional harmonic traps. Here, we extend these states to the regime of large chemical potentials, the so-called Thomas-Fermi limit, and explore their properties such as equilibrium radii and inter-ring distance, for multi-ring states, as well as their vibrational spectra and possible instabilities. In this limit, both the existence and stability characteristics can be partially traced to a particle picture that considers the rings as individual particles oscillating within the trap and interacting pairwise with one another. Finally, we examine some representative instability scenarios of the multi-ring dynamics including breakup and reconnections, as well as the transient formation of vortex lines.Comment: 10 pages, 8 figure

    Lateral epicondylalgia exhibits adaptive muscle activation strategies based on wrist posture and levels of grip force: a case-control study

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    Objectives: To investigate forearm muscle activity in individuals with lateral epicondylalgia (LE) when gripping at different wrist postures, and investigate the association between muscle activity and clinical characteristics of LE. Methods: Eleven LE and 11 healthy participants performed isometric handgrips at 15% and 30% of maximum grip force (MVC). Gripping was performed in wrist extension, wrist flexion, and wrist neutral. Surface electromyography was collected from six forearm muscles. Standard clinical and tendon structural measures for LE were obtained. Results: LE group had reduced magnitude of extensor carpi radialis brevis (ECRB) with increased contribution of extensor carpi ulnaris (ECU) during 15% MVC. However, during 30% MVC the LE group had reduced flexor carpi radialis and flexor digitorum superficialis activity, which was coupled with increased contribution from extensor digitorum communis (EDC) and ECU. Although ECRB and ECU activity differed in wrist flexion compared to other wrist postures for controls, different wrist posture had no effect on forearm muscle activation in LE. Pain and disability, and tendon thickness had significant associations with EDC and ECRB activity respectively in LE. Conclusion: Individuals with LE use different neuromuscular strategies when gripping with different wrist postures which appears to be dependent on the level of grip force

    Implementation of boolean neural networks on parallel computers

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    This paper analyses the parallel implementation using networks of transputers of a neural structure belonging to a particular class of neural architectures known as GSN neural networks. These architectures, belonging to the general clasa of RAM-based networks and composed 01 digitally specified processing nodes, have been implemented using different processing topologies, and performance in relatíon to both training and testing efficiency in a practical pattern recognition task has been evaluated.Eje: Redes Neuronales. Algoritmos genéticosRed de Universidades con Carreras en Informática (RedUNCI

    Electric Dipole Moments in the Generic Supersymmetric Standard Model

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    The generic supersymmetric standard model is a model built from a supersymmetrized standard model field spectrum the gauge symmetries only. The popular minimal supersymmetric standard model differs from the generic version in having R-parity imposed by hand. We review an efficient formulation of the model and some of the recently obtained interesting phenomenological features, focusing on one-loop contributions to fermion electric dipole moments.Comment: 1+7 pages Revtex 3 figures incoporated; talk at NANP'0

    An integrative model of lateral epicondylalgia

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    Tennis elbow or lateral epicondylalgia is a diagnosis familiar to many within the general community and presents with an uncomplicated clinical picture in most cases. However, the underlying pathophysiology presents a more complex state and its management has not been conclusively determined. Research on this topic extends across anatomical, biomechanical and clinical literature; however, integration of findings is lacking. We propose that the current understanding of the underlying pathophysiology of lateral epicondylalgia can be conceptualised as encompassing three interrelated components: (i) the local tendon pathology, (ii) changes in the pain system, and (iii) motor system impairments. This paper presents a model that integrates these components on the basis of a literature review with the express aim of assisting in the targeting of specific treatments or combinations thereof to individual patients

    Wedgebox analysis of four-lepton events from neutralino pair production at the LHC

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    `Wedgebox' plots constructed by plotting the di-electron invariant mass versus the di-muon invariant mass from pp -> e^+e^- mu^+ mu^- + missing energy signature LHC events. Data sets of such events are obtained across the MSSM input parameter space in event-generator simulations, including cuts designed to remove SM backgrounds. Their study reveals several general features: (1)Regions in the MSSM input parameter space where a sufficient number of events are expected so as to be able to construct a clear wedgebox plot are delineated. (2)The presence of box shapes on a wedgebox plot either indicates the presence of heavy Higgs bosons decays or restricts the location to a quite small region of low \mu and M_2 values \lsim 200 GeV, a region denoted as the `lower island'. In this region, wedgebox plots can be quite complicated and change in pattern rather quickly as one moves around in the (\mu, M_2) plane. (3)Direct neutralino pair production from an intermediate Z^{0*} may only produce a wedge-shape since only \widetilde{\chi}_2^0\widetilde{\chi}_3^0 decays can contribute significantly. (4)A double-wedge or wedge-protruding-from-a-box pattern on a wedgebox plot, which results from combining a variety of MSSM production processes, yields three distinct observed endpoints, almost always attributable to \widetilde{\chi}_{2,3,4}^0 \to \widetilde{\chi}_1^0 \ell^+\ell^- decays, which can be utilized to determine a great deal of information about the neutralino and slepton mass spectra and related MSSM input parameters. Wedge and double-wedge patterns are seen in wedgebox plots in another region of higher \mu and M_2 values, denoted as the`upper island.' Here the pattern is simpler and more stable as one moves across the (\mu, M_2) input parameter space.Comment: 28 pages (LaTeX), 8 figures (encapsulated postscript
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