3,781 research outputs found

    Energy Eigenvalues For Supersymmetric Potentials via Quantum Hamilton-Jacobi Formalism

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    Using quantum Hamilton-Jacobi formalism of Leacock and Padgett, we show how to obtain the exact eigenvalues for supersymmetric (SUSY) potentials.Comment: 15 pages Latex Compile twice to get cross references correct. 2 Figures not included. Requests for figures should be sent to [email protected]

    Heuristic Backtracking Algorithms for SAT

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    In recent years backtrack search SAT solvers have been the subject of dramatic improvements. These improvements allowed SAT solvers to successfully replace BDDs in many areas of formal verification, and also motivated the development of many new challenging problem instances, many of which too hard for the current generation of SAT solvers. As a result, further improvements to SAT technology are expected to have key consequences in formal verification. The objective of this paper is to propose heuristic approaches to the backtrack step of backtrack search SAT solvers, with the goal of increasing the ability of the SAT solver to search different parts of the search space. The proposed heuristics to the backtrack step are inspired by the heuristics proposed in recent years for the branching step of SAT solvers, namely VSIDS and some of its improvements. The preliminary experimental results are promising, and motivate the integration of heuristic backtracking in state-of-the-art SAT solvers. 1

    Performance Assessment of Six Public Health Programs in Katsina State, Nigeria

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    This research aimed to evaluate the performance of six ongoing public health programs through core performance indicators in Katsina State, Nigeria. The healthcare delivery in Africa is mostly program-based. This requires that such programs need to be evaluated which may in turn help to identify any existing gaps towards the improvement of patients' access and coverage to their given service. We identified all active health facilities where our programs on malaria, Routine Immunization (RI), Family Planning (FP), Tuberculosis and Leprosy (TBL), HIV/AIDS, and Free Medicare (FMC) were being carried out. After that, a representative sample was derived to obtain data regarding five key performance indicators by using a Logistics Indicators Assessment Tool. Of 1,718 facilities, a total of 983 (57.22%) were visited, In other words, by assuming a normal distribution; each facility expectedly covers only 3,371 individuals. All programs provided different and diverse results on each indicator; however, the most obvious challenge was in the stock-out and demand vs. receipt of required medications. These are particularly for malaria, FMC, FP, and HIV. For instance, the stock-out lasted 222 days for malaria and 135 days for FP. Despite this, none of the programs had a lower than gold-standard near-term availability of required products. Program-based healthcare delivery is inadequate and ineffective unless the local system gets simultaneously developed. If required medications are not becoming available, optimal access, coverage, and benefits cannot be expected to be obtained. Clearly, Nigeria experiences a push system of meeting term supplies. Nigeria needs to strengthen its pharmaceutical system

    Tunneling magnetoresistance in (La,Pr,Ca)MnO3 nanobridges

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    The manganite (La,Pr,Ca)MnO3 is well known for its micrometer scale phase separation into coexisting ferromagnetic metallic and antiferromagnetic insulating (AFI) regions. Fabricating bridges with widths smaller than the phase separation length scale has allowed us to probe the magnetic properties of individual phase separated regions. We observe tunneling magnetoresistance across naturally occurring AFI tunnel barriers separating adjacent ferromagnetic regions spanning the width of the bridges. Further, near the Curie temperature, a magnetic field induced metal-to-insulator transition among a discrete number of regions within the narrow bridges gives rise to abrupt and colossal low-field magnetoresistance steps at well defined switching fields.Comment: 13 pages, 3 figures, submitted to Applied Physics Letter

    A moving control volume approach to computing hydrodynamic forces and torques on immersed bodies

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    We present a moving control volume (CV) approach to computing hydrodynamic forces and torques on complex geometries. The method requires surface and volumetric integrals over a simple and regular Cartesian box that moves with an arbitrary velocity to enclose the body at all times. The moving box is aligned with Cartesian grid faces, which makes the integral evaluation straightforward in an immersed boundary (IB) framework. Discontinuous and noisy derivatives of velocity and pressure at the fluid-structure interface are avoided and far-field (smooth) velocity and pressure information is used. We re-visit the approach to compute hydrodynamic forces and torques through force/torque balance equation in a Lagrangian frame that some of us took in a prior work (Bhalla et al., J Comp Phys, 2013). We prove the equivalence of the two approaches for IB methods, thanks to the use of Peskin's delta functions. Both approaches are able to suppress spurious force oscillations and are in excellent agreement, as expected theoretically. Test cases ranging from Stokes to high Reynolds number regimes are considered. We discuss regridding issues for the moving CV method in an adaptive mesh refinement (AMR) context. The proposed moving CV method is not limited to a specific IB method and can also be used, for example, with embedded boundary methods
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