20,526 research outputs found

    Opportunities and Challenges: The Caribbean Involvement in Free Trade Area ofthe Americas

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    This Article will examine the region\u27s participation in the process leading to the establishment of the FTAA, and the benefits and challenges associated with its involvement in this hemispheric undertaking. Part One of the Article sets out the rationale for the establishment of the FTAA and the structure of the negotiations. The section also identifies some elements of the unique nature of the proposed grouping. Part Two discusses the challenges facing Caribbean countries as they participate in multilateral trade negotiations, including the FTAA. In Part Three, the Article critically reviews the early stages of the integration process in the Caribbean and examines the most recent developments in the process, particularly in the context of the process of globalization and liberalization. This is followed by Part Four, which discusses the Caribbean\u27s participation in the FTAA

    Opportunities and Challenges: The Caribbean Involvement in the Free Trade Area of the Americas

    Get PDF
    This Article will examine the region\u27s participation in the process leading to the establishment of the FTAA, and the benefits and challenges associated with its involvement in this hemispheric undertaking. Part One of the Article sets out the rationale for the establishment of the FTAA and the structure of the negotiations. The section also identifies some elements of the unique nature of the proposed grouping. Part Two discusses the challenges facing Caribbean countries as they participate in multilateral trade negotiations, including the FTAA. In Part Three, the Article critically reviews the early stages of the integration process in the Caribbean and examines the most recent developments in the process, particularly in the context of the process of globalization and liberalization. This is followed by Part Four, which discusses the Caribbean\u27s participation in the FTAA

    IMPMOT user's manual

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    This user's manual describes the input and output variables as well as the job control language necessary to utilize the IMP-H apogee motor firing program, IMPMOT. The IMPMOT program can be executed as either a stand-alone program or as a member of the flight dynamics system. This program is used to determine the time and attitude at which to fire the IMP-H apogee boost motor. The IMPMOT program is written in FORTRAN 4 for use on the IBM 360 series computer

    High-Order Coupled Cluster Method Calculations for the Ground- and Excited-State Properties of the Spin-Half XXZ Model

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    In this article, we present new results of high-order coupled cluster method (CCM) calculations, based on a N\'eel model state with spins aligned in the zz-direction, for both the ground- and excited-state properties of the spin-half {\it XXZ} model on the linear chain, the square lattice, and the simple cubic lattice. In particular, the high-order CCM formalism is extended to treat the excited states of lattice quantum spin systems for the first time. Completely new results for the excitation energy gap of the spin-half {\it XXZ} model for these lattices are thus determined. These high-order calculations are based on a localised approximation scheme called the LSUBmm scheme in which we retain all kk-body correlations defined on all possible locales of mm adjacent lattice sites (k≤mk \le m). The ``raw'' CCM LSUBmm results are seen to provide very good results for the ground-state energy, sublattice magnetisation, and the value of the lowest-lying excitation energy for each of these systems. However, in order to obtain even better results, two types of extrapolation scheme of the LSUBmm results to the limit m→∞m \to \infty (i.e., the exact solution in the thermodynamic limit) are presented. The extrapolated results provide extremely accurate results for the ground- and excited-state properties of these systems across a wide range of values of the anisotropy parameter.Comment: 31 Pages, 5 Figure

    Ab Initio Simulation of the Nodal Surfaces of Heisenberg Antiferromagnets

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    The spin-half Heisenberg antiferromagnet (HAF) on the square and triangular lattices is studied using the coupled cluster method (CCM) technique of quantum many-body theory. The phase relations between different expansion coefficients of the ground-state wave function in an Ising basis for the square lattice HAF is exactly known via the Marshall-Peierls sign rule, although no equivalent sign rule has yet been obtained for the triangular lattice HAF. Here the CCM is used to give accurate estimates for the Ising-expansion coefficients for these systems, and CCM results are noted to be fully consistent with the Marshall-Peierls sign rule for the square lattice case. For the triangular lattice HAF, a heuristic rule is presented which fits our CCM results for the Ising-expansion coefficients of states which correspond to two-body excitations with respect to the reference state. It is also seen that Ising-expansion coefficients which describe localised, mm-body excitations with respect to the reference state are found to be highly converged, and from this result we infer that the nodal surface of the triangular lattice HAF is being accurately modeled. Using these results, we are able to make suggestions regarding possible extensions of existing quantum Monte Carlo simulations for the triangular lattice HAF.Comment: 24 pages, Latex, 3 postscript figure

    Coupled Cluster Method Calculations Of Quantum Magnets With Spins Of General Spin Quantum Number

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    We present a new high-order coupled cluster method (CCM) formalism for the ground states of lattice quantum spin systems for general spin quantum number, ss. This new ``general-ss'' formalism is found to be highly suitable for a computational implementation, and the technical details of this implementation are given. To illustrate our new formalism we perform high-order CCM calculations for the one-dimensional spin-half and spin-one antiferromagnetic {\it XXZ} models and for the one-dimensional spin-half/spin-one ferrimagnetic {\it XXZ} model. The results for the ground-state properties of the isotropic points of these systems are seen to be in excellent quantitative agreement with exact results for the special case of the spin-half antiferromagnet and results of density matrix renormalisation group (DMRG) calculations for the other systems. Extrapolated CCM results for the sublattice magnetisation of the spin-half antiferromagnet closely follow the exact Bethe Ansatz solution, which contains an infinite-order phase transition at Δ=1\Delta=1. By contrast, extrapolated CCM results for the sublattice magnetisation of the spin-one antiferromagnet using this same scheme are seen to go to zero at Δ≈1.2\Delta \approx 1.2, which is in excellent agreement with the value for the onset of the Haldane phase for this model. Results for sublattice magnetisations of the ferrimagnet for both the spin-half and spin-one spins are non-zero and finite across a wide range of Δ\Delta, up to and including the Heisenberg point at Δ=1\Delta=1.Comment: 5 Figures. J. Stat. Phys. 108, p. 401 (2002

    A computer program for the calculation of the flow field in supersonic mixed-compression inlets at angle of attack using the three-dimensional method of characteristics with discrete shock wave fitting

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    The calculation procedure is based on the method of characteristics for steady three-dimensional flow. The bow shock wave and the internal shock wave system were computed using a discrete shock wave fitting procedure. The general structure of the computer program is discussed, and a brief description of each subroutine is given. All program input parameters are defined, and a brief discussion on interpretation of the output is provided. A number of sample cases, complete with data deck listings, are presented
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