7,017 research outputs found

    On Minimax Fractional Optimality Conditions with Invexity

    Get PDF
    AbstractUnder different forms of invexity conditions, sufficient Kuhn–Tucker conditions and three dual models are presented for the minimax fractional programming

    Hamiltonian Structures for the Ostrovsky-Vakhnenko Equation

    Full text link
    We obtain a bi-Hamiltonian formulation for the Ostrovsky-Vakhnenko equation using its higher order symmetry and a new transformation to the Caudrey-Dodd-Gibbon-Sawada-Kotera equation. Central to this derivation is the relation between Hamiltonian structures when dependent and independent variables are transformed.Comment: 13 page

    A novel route to phase formation of cobalt oxyhydrates using KMnO4 as an oxidizing agent

    Full text link
    We have first succeefully synthesized the sodium cobalt oxyhydrate superconductors using KMnO4 as a de-intercalating and oxidizing agent. It is a novel route to form the superconductive phase of NaxCoO2.yH2O without resorting to the commonly used Br2/CH3CN solution. The role of the KMnO4 is to de-intercalate the Na+ from the parent compound Na0.7CoO2 and oxidize the Co ion as a result. The higher molar ratio of KMnO4 relative to the sodium content tends to remove more Na+ from the parent compound and results in a slight expansion of the c-axis in the unit cell. The superconducting transition temperature is 4.6-3.8 K for samples treated by the aqueous KMnO4 solution with the molar ratio of KMnO4 relative to the sodium content in the range of 0.3 and 2.29.Comment: 10 pages, 3 figure

    Axial vector current in an electromagnetic field and low-energy neutrino-photon interactions

    Full text link
    An expression for the axial vector current in a strong, slowly varying electromagnetic field is obtained. We apply this expression to the construction of the effective action for low-energy neutrino-photon interactions.Comment: 6 pages, references updated, final version to appear in Phys. Rev.

    Surface critical behavior in fixed dimensions d<4d<4: Nonanalyticity of critical surface enhancement and massive field theory approach

    Full text link
    The critical behavior of semi-infinite systems in fixed dimensions d<4d<4 is investigated theoretically. The appropriate extension of Parisi's massive field theory approach is presented.Two-loop calculations and subsequent Pad\'e-Borel analyses of surface critical exponents of the special and ordinary phase transitions yield estimates in reasonable agreement with recent Monte Carlo results. This includes the crossover exponent Φ(d=3)\Phi (d=3), for which we obtain the values Φ(n=1)≃0.54\Phi (n=1)\simeq 0.54 and Φ(n=0)≃0.52\Phi (n=0)\simeq 0.52, considerably lower than the previous ϵ\epsilon-expansion estimates.Comment: Latex with Revtex-Stylefiles, 4 page

    Digital technologies in support of flood resilience: A case study for Nepal

    Get PDF
    This paper presents ongoing efforts to support flood resilience in the Karnali basin in Nepal through the provision of different forms of digital technology. Flood Risk Geo-Wiki is an online visualization and crowdsourcing tool, which has been adapted to display flood risk maps at the global scale as well as information of relevance to planners and the community at the local level. Community-based flood risk maps, which have traditionally been drawn on paper, are being digitized and integrated with OpenStreetMap to provide better access to this collective knowledge base. Mobile phones, using the GeoODK (Geographical Open Data Kit) questionnaire builder, are being deployed to collect georeferenced information on flood risks and vulnerability, which can be used to validate flood models and design action plans and strategies for coping with future flood events. These types of digital technologies are simple to implement yet together can help support flood prone communities

    Glueball spectrum based on a rigorous three-dimensional relativistic equation for two-gluon bound states II: calculation of the glueball spectrum

    Full text link
    In the preceding paper, a rigorous three-dimensional relativistic equation for two-gluon bound states was derived from the QCD with massive gluons and represented in the angular momentum representation. In order to apply this equation to calculate the glueball spectrum, in this paper, the equation is recast in an equivalent three-dimensional relativistic equation satisfied by the two-gluon positive energy state amplitude. The interaction Hamiltonian in the equation is exactly derived and expressed as a perturbative series. The first term in the series describes the one-gluon exchange interaction which includes fully the retardation effect in it. This term plus the linear confining potential are chosen to be the interaction Hamiltonian and employed in the practical calculation. With the integrals containing three and four spherical Bessel functions in the QCD vertices being analytically calculated, the interaction Hamiltonian is given an explicit expression in the angular momentum representation. Numerically solving the relativistic equation with taking the contributions arising from the retardation effect and the longitudinal mode of gluon fields into account, a set of masses for the 0++,0−+,1++,1−+,2++0^{++},0^{-+},1^{++},1^{-+},2^{++} and 2−+2^{-+\text{}} glueball states are obtained and are in fairly good agreement with the predictions given by the lattice simulatio

    Quark Effects in the Gluon Condensate Contribution to the Scalar Glueball Correlation Function

    Full text link
    One-loop quark contributions to the dimension-four gluon condensate term in the operator product expansion (OPE) of the scalar glueball correlation function are calculated in the MS-bar scheme in the chiral limit of nfn_f quark flavours. The presence of quark effects is shown not to alter the cancellation of infrared (IR) singularities in the gluon condensate OPE coefficients. The dimension-four gluonic condensate term represents the leading power corrections to the scalar glueball correlator and, therein, the one-loop logarithmic contributions provide the most important condensate contribution to those QCD sum-rules independent of the low-energy theorem (the subtracted sum-rules).Comment: latex2e, 6 pages, 7 figures embedded in latex fil
    • …
    corecore