609 research outputs found

    Equal Protection - Property Taxes as a Method of Funding Public Education; San Antonio Independent School District v. Rodriguez

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    Suit was brought in U.S. District Court for the Western District of Texas challenging the constitutionality of the Texas school financing system on the theory that it discriminated on a basis of wealth, permitting provision of a higher quality of education to be offered the children in property-rich school districts while residents pay a lower tax rate, thus denying equal protection of the law.\u27 The District Court found the laws forming this system unconstitutional on this basis. Appeal brought the case to the Supreme Court in October of 1972, where it was reversed

    The governance of European security

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    This article seeks to develop a concept of ‘security governance’ in the context of post-Cold War Europe. The validity of a governance approach lies in its ability to locate some of the distinctive ways in which European security has been coordinated, managed and regulated. Based on an examination of the way governance is utilised in other political fields of political analysis, the article identifies the concept of security governance as involving the coordinated management and regulation of issues by multiple and separate authorities, the interventions of both public and private actors (depending upon the issue), formal and informal arrangements, in turn structured by discourse and norms, and purposefully directed toward particular policy outcomes. Three issues are examined to demonstrate the utility of the concept of security governance for understanding security in post-Cold War Europe: the transformation of NATO, the Europeanisation of security accomplished through EU-led initiatives and, finally, the resultant dynamic relationship between forms of exclusion and inclusion in governance

    Heap Leaching: Modelling and Forecasting Using CFD Technology

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    Heap leach operations typically employ some form of modelling and forecasting tools to predict cash flow margins and project viability. However, these vary from simple spreadsheets to phenomenological models, with more complex models not commonly employed as they require the greatest amount of time and effort. Yet, accurate production modelling and forecasting are essential for managing production and potentially critical for successful operation of a complex heap, time and effort spent in setting up modelling tools initially may increase profitability in the long term. A brief overview of various modelling approaches is presented, but this paper focuses on the capabilities of a computational fluid dynamics (CFD) model. Advances in computational capability allow for complex CFD models, coupled with leach kinetic models, to be applied to complex ore bodies. In this paper a comprehensive hydrodynamic CFD model is described and applied to chalcopyrite dissolution under heap operating conditions. The model is parameterized against experimental data and validated against a range of experimental leach tests under different thermal conditions. A three-dimensional ‘virtual’ heap, under fluctuating meteorological conditions, is simulated. Continuous and intermittent irrigation is investigated, showing copper recovery per unit volume of applied leach solution to be slightly increased for pulse irrigation

    Accuracy of the QUAD4 thick shell element

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    The accuracy of the relatively new QUAD4 thick shell element is assessed via comparison with a theoretical solution for thick homogeneous and honeycomb flat simply supported plates under the action of a uniform pressure load. The theoretical thick plate solution is based on the theory developed by Reissner and includes the effects of transverse shear flexibility which are not included in the thin plate solutions based on Kirchoff plate theory. In addition, the QUAD4 is assessed using a set of finite element test problems developed by the MacNeal-Schwendler Corp. (MSC). Comparison of the COSMIC QUAD4 element as well as those from MSC and Universal Analytics, Inc. (UAI) for these test problems is presented. The current COSMIC QUAD4 element is shown to have excellent comparison with both the theoretical solutions and also those from the two commercial versions of NASTRAN that it was compared to

    Stereodynamical Control of a Quantum Scattering Resonance in Cold Molecular Collisions

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    Cold collisions of light molecules are often dominated by a single partial wave resonance. For the rotational quenching of HD (v=1, j=2) by collisions with ground state para-H2, the process is dominated by a single L=2 partial wave resonance centered around 0.1 K. Here, we show that this resonance can be switched on or off simply by appropriate alignment of the HD rotational angular momentum relative to the initial velocity vector, thereby enabling complete control of the collision outcome

    Continuous Trait-Based Particle Swarm Optimisation (CTB-PSO)

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    Copyright © 2012 Springer Verlag. The final publication is available at link.springer.com8th International Conference, ANTS 2012, Brussels, Belgium, September 12-14, 2012. ProceedingsIn natural flocks, individuals are often of the same species, but there exists considerable variation in the traits possessed by each individual. In much the same way as humans display varied levels of aggression, gregariousness and inquisitiveness, so do the animals on which PSO is based [1]. Recent research has shown that this disparity of behaviour is very important in the ability of the flock to solve problems effectively, which might have profound implications for PSO. One of the key aspects is that although certain behaviour types (e.g. more adventurous individuals) might individually be better at problem solving; selecting for a group that all have adventurous traits has been shown to reduce the performance of the flock as a whole [1]. Therefore a flock that has a variety of behaviours leads to better performance in natural systems and it is this that motivates the work here. This paper explores a variant of PSO known as Continuous Trait-Based PSO (CTB-PSO) where individuals within a swarm have traits based on a continuous scale as opposed to discrete behaviour groupings

    Rejuvenating Power Spectra II: the Gaussianized galaxy density field

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    We find that, even in the presence of discreteness noise, a Gaussianizing transform (producing a more-Gaussian one-point distribution) reduces nonlinearities in the power spectra of cosmological matter and galaxy density fields, in many cases drastically. Although Gaussianization does increase the effective shot noise, it also increases the power spectrum's fidelity to the linear power spectrum on scales where the shot noise is negligible. Gaussianizing also increases the Fisher information in the power spectrum in all cases and resolutions, although the gains are smaller in redshift space than in real space. We also find that the gain in cumulative Fisher information from Gaussianizing peaks at a particular grid resolution that depends on the sampling level.Comment: Slight changes to match version accepted to ApJ. 7 pages, 8 figure
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