39,857 research outputs found

    Charged coherent states related to su_{q}(2) covariance

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    A new kind of q-deformed charged coherent states is constructed in Fock space of two-mode q-boson system with su_{q}(2) covariance and a resolution of unity for these states is derived. We also present a simple way to obtain these coherent states using state projection method.Comment: 7 pages. To appear in Modern Phyics Letter:

    Project delivery in HIV/AIDS and TB in Southern Africa: the cross-cultural management imperative.

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    This paper reports the findings of a broad based study that initially investigated a possible gap in global inputs into the fight against HIV/AIDS and TB co-infection, and outputs in terms of results achieved. We propose that such a gap may be hypothesized to be due, at least in part, to inappropriate management regimes within the global health governance structure. We do not simply question the effectiveness of the management of programs and projects, but rather the inappropriateness resulting from the lack of addressing cross-cultural issues. The factors facilitating or hampering project service delivery are examined by looking at twelve case studies in Botswana and South Africa. These data are complemented with seven semi-structured interviews with donor organizations and NGOs conducted in the North. Cultural interactions are investigated by using the concept of ‘interfaces’. Results suggest that there is a disjuncture between the global and local level that affects project delivery. The main issues hampering project outcomes can be summarized as systemic, structural and cultural. The article’s main contributions are both theoretical, looking at global project delivery from a cross-cultural management perspective, as well as to development praxis by highlighting the need to focus more critically on cross-cultural management issues within the global health governance structure, and indeed within international development as a whole

    Random Walkers with Shrinking Steps in d-Dimensions and Their Long Term Memory

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    We study, in d-dimensions, the random walker with geometrically shrinking step sizes at each hop. We emphasize the integrated quantities such as expectation values, cumulants and moments rather than a direct study of the probability distribution. We develop a 1/d expansion technique and study various correlations of the first step to the position as ti me goes to infinity. We also show and substantiate with a study of the cumulants that to order 1/d the system admits a continuum counterpart equation which can be obtained with a generalization of the ordinary technique to obtain the continuum limit. We also advocate that this continuum counterpart equation, which is nothing but the ordinary diffusion equation with a diffusion constant decaying exponentially in continuous time, captures all the qualitative aspects of t he discrete system and is often a good starting point for quantitative approximations

    Aircraft and satellite measurement of ocean wave directional spectra using scanning-beam microwave radars

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    A microwave radar technique for remotely measuring the vector wave number spectrum of the ocean surface is described. The technique, which employs short-pulse, noncoherent radars in a conical scan mode near vertical incidence, is shown to be suitable for both aircraft and satellite application, the technique was validated at 10 km aircraft altitude, where we have found excellent agreement between buoy and radar-inferred absolute wave height spectra

    The 4D geometric quantities versus the usual 3D quantities. The resolution of Jackson's paradox

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    In this paper we present definitions of different four-dimensional (4D) geometric quantities (Clifford multivectors). New decompositions of the torque N and the angular momentum M (bivectors) into 1-vectors N_{s}, N_{t} and M_{s}, M_{t} respectively are given. The torques N_{s}, N_{t} (the angular momentums M_{s}, M_{t}), taken together, contain the same physical information as the bivector N (the bivector M). The usual approaches that deal with the 3D quantities E\mathbf{E}, B\mathbf{B}, F\mathbf{F}, L\mathbf{L}, N\mathbf{N}, etc. and their transformations are objected from the viewpoint of the invariant special relativity (ISR). In the ISR it is considered that 4D geometric quantities are well-defined both theoretically and \emph{experimentally} in the 4D spacetime. This is not the case with the usual 3D quantities. It is shown that there is no apparent electrodynamic paradox with the torque, and that the principle of relativity is naturally satisfied, when the 4D geometric quantities are used instead of the 3D quantities.Comment: 13 pages, revte

    Many-body effects on the capacitance of multilayers made from strongly correlated materials

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    Recent work by Kopp and Mannhart on novel electronic systems formed at oxide interfaces has shown interesting effects on the capacitances of these devices. We employ inhomogeneous dynamical mean-field theory to calculate the capacitance of multilayered nanostructures. These multilayered nanostructures are composed of semi-infinite metallic leads coupled via a strongly correlated dielectric barrier region. The barrier region can be adjusted from a metallic regime to a Mott insulator through adjusting the interaction strength. We examine the effects of varying the barrier width, temperature, potential difference, screening length, and chemical potential. We find that the interaction strength has a relatively strong effect on the capacitance, while the potential and temperature show weaker dependence.Comment: 19 pages, 7 figures, REVTe

    Finite temperature theory of the scissors mode in a Bose gas using the moment method

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    We use a generalized Gross-Pitaevskii equation for the condensate and a semi-classical kinetic equation for the noncondensate atoms to discuss the scissors mode in a trapped Bose-condensed gas at finite temperatures. Both equations include the effect of C12C_{12} collisions between the condensate and noncondensate atoms. We solve the coupled moment equations describing oscillations of the quadrupole moments of the condensate and noncondensate components to find the collective mode frequencies and collisional damping rates as a function of temperature. Our calculations extend those of Gu\'ery-Odelin and Stringari at T=0 and in the normal phase. They complement the numerical results of Jackson and Zaremba, although Landau damping is left out of our approach. Our results are also used to calculate the quadrupole response function, which is related to the moment of inertia. It is shown explicitly that the moment of inertia of a trapped Bose gas at finite temperatures involves a sum of an irrotational component from the condensate and a rotational component from the thermal cloud atoms.Comment: 18 pages, 8 figure

    Implementation of OpenFOAM for Inviscid Incompressible Aerodynamic Flows

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    This paper is the description of the Utah State University AeroLab’s Aerodynamic Center Analysis Tool (AeroCAT), which is an implementation of the OpenFOAM CFD toolbox. AeroCAT takes in a user input file, generates a mesh, and solves a steady, inviscid, incompressible flow, automatically repeating the process for a range of angles of attack. It then processes the results to predict the wing’s span-wise locus of aerodynamic centers. The mesh generator used in this tool is GridX, developed by a former PhD student at USU, and the CFD solver is OpenFOAM

    Life long learning in rural areas: a report to the Countryside Agency

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    Lifelong Learning is a broad umbrella term which includes many different kinds of provision and different forms of learning. At its heart is formal learning, often classroom based, or involving paper and electronic media, undertaken within educational institutions such as colleges and universities. It may or may not lead to an award and it includes learning undertaken for vocational reasons as well as for general interest. It encompasses what are sometimes also known as adult education, continuing education, continuing professional development (cpd), vocational training and the acquisition of basic skills. It may also include work-based learning, and may overlap with post compulsory (post 16) education, i.e. with further education and higher education, but normally applies to all ‘adult learning’ i.e. by people over the age of 19, in particular those who are returning to study after completing their initial education. From the perspective of the individual learner, however, non-formal learning (organised, systematic study carried on outside the framework of the formal system) is also important. This forms a continuum with informal learning that occurs frequently in the process of daily living, sometimes coincidentally for example through information media or through interpretive provision (such as at museums or heritage sites ). This report focuses on those aspects of adult learning which are directly affected by government policies, and thus of prime concern for rural proofing
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