3,928 research outputs found

    21st century social work: reducing re-offending - key practice skills

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    This literature review was commissioned by the Scottish Executive’s Social Work Services Inspectorate in order to support the work of the 21st Century Social Work Review Group. Discussions in relation to the future arrangements for criminal justice social work raised issues about which disciplines might best encompass the requisite skills for reducing re-offending in the community. Rather than starting with what is known or understood about the skills of those professionals currently involved in such interventions, this study sought to start with the research evidence on effective work with offenders to reduce re-offending and then work its way back to the skills required to promote this outcome

    Exact solution for random walks on the triangular lattice with absorbing boundaries

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    The problem of a random walk on a finite triangular lattice with a single interior source point and zig-zag absorbing boundaries is solved exactly. This problem has been previously considered intractable.Comment: 10 pages, Latex, IOP macro

    Magnetic Susceptibility of an integrable anisotropic spin ladder system

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    We investigate the thermodynamics of a spin ladder model which possesses a free parameter besides the rung and leg couplings. The model is exactly solved by the Bethe Ansatz and exhibits a phase transition between a gapped and a gapless spin excitation spectrum. The magnetic susceptibility is obtained numerically and its dependence on the anisotropy parameter is determined. A connection with the compounds KCuCl3, Cu2(C5H12N2)2Cl4 and (C5H12N)2CuBr4 in the strong coupling regime is made and our results for the magnetic susceptibility fit the experimental data remarkably well.Comment: 12 pages, 12 figures included, submitted to Phys. Rev.

    Energetics and dynamics of simple impulsive solar flares

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    Flare energetics and dynamics were studied using observations of simple impulsive spike bursts. A large, homogeneous set of events was selected to enable the most definite tests possible of competing flare models, in the absence of spatially resolved observations. The emission mechanisms and specific flare models that were considered in this investigation are described, and the derivations of the parameters that were tested are presented. Results of the correlation analysis between soft and hard X-ray energetics are also presented. The ion conduction front model and tests of that model with the well-observed spike bursts are described. Finally, conclusions drawn from this investigation and suggestions for future studies are discussed

    Substrate-Integrated Folded Waveguide Slot Antenna

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    In recent years a number of researchers have proposed novel techniques for fabricating rectangular waveguide using microwave integrated circuit techniques. These so-called substrate integrated guides have been fabricated using multilayer LTCC, multi- and single-layer microwave laminates and photoimageable thick films. All of these structures result in dielectric filled rectangular waveguide and as such have a width reduction of 1/square root of the relative permittivity over conventional waveguide. Furthermore, by their very nature they are easily integrated with planar transmission lines and circuits, allowing hybrid waveguide/microstrip systems to be fabricated on a single substrate. Several researchers have investigated slot antennas and arrays in substrate-integrated guide. In this paper we show a slot antenna in a folded substrate-integrated waveguide. These waveguides have half the width of the other types of substrate-integrated waveguide. As such the present structure allows arrays of slot antennas to be more highly integrated

    Random walks on finite lattice tubes

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    Exact results are obtained for random walks on finite lattice tubes with a single source and absorbing lattice sites at the ends. Explicit formulae are derived for the absorption probabilities at the ends and for the expectations that a random walk will visit a particular lattice site before being absorbed. Results are obtained for lattice tubes of arbitrary size and each of the regular lattice types; square, triangular and honeycomb. The results include an adjustable parameter to model the effects of strain, such as surface curvature, on the surface diffusion. Results for the triangular lattice tubes and the honeycomb lattice tubes model diffusion of adatoms on single walled zig-zag carbon nano-tubes with open ends.Comment: 22 pages, 4 figure

    Capillary rise of a liquid between two vertical plates making a small angle.

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    The penetration of a wetting liquid in the narrow gap between two vertical plates making a small angle is analyzed in the framework of the lubrication approximation. At the beginning of the process, the liquid rises independently at different distances from the line of intersection of the plates except in a small region around this line where the effect of the gravity is negligible. The maximum height of the liquid initially increases as the cubic root of time and is attained at a point that reaches the line of intersection only after a certain time. At later times, the motion of the liquid is confined to a thin layer around the line of intersection whose height increases as the cubic root of time and whose thickness decreases as the inverse of the cubic root of time. The evolution of the liquid surface is computed numerically and compared with the results of a simple experiment

    Transport in a highly asymmetric binary fluid mixture

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    We present molecular dynamics calculations of the thermal conductivity and viscosities of a model colloidal suspension with colloidal particles roughly one order of magnitude larger than the suspending liquid molecules. The results are compared with estimates based on the Enskog transport theory and effective medium theories (EMT) for thermal and viscous transport. We find, in particular, that EMT remains well applicable for predicting both the shear viscosity and thermal conductivity of such suspensions when the colloidal particles have a ``typical'' mass, i.e. much larger than the liquid molecules. Very light colloidal particles on the other hand yield higher thermal conductivities, in disagreement with EMT. We also discuss the consequences of these results to some proposed mechanisms for thermal conduction in nanocolloidal suspensions.Comment: 13 pages, 6 figures, to appear in Physical Review E (2007

    Scaling and universality in the 2D Ising model with a magnetic field

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    The scaling function of the 2D Ising model in a magnetic field on the square and triangular lattices is obtained numerically via Baxter's variational corner transfer matrix approach. The use of the Aharony-Fisher non-linear scaling variables allowed us to perform calculations sufficiently away from the critical point to obtain very high precision data, which convincingly confirm all predictions of the scaling and universality hypotheses. The results are in excellent agreement with the field theory calculations of Fonseca and Zamolodchikov as well as with many previously known exact and numerical results for the 2D Ising model. This includes excellent agreement with the classic analytic results for the magnetic susceptibility by Barouch, McCoy, Tracy and Wu, recently enhanced by Orrick, Nickel, Guttmann and Perk.Comment: 5 pages, 1 figur

    On the Uq[sl(2)]{\cal{U}}_{q}[sl(2)] Temperley-Lieb reflection matrices

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    This work concerns the boundary integrability of the spin-s Uq[sl(2)]{\cal{U}}_{q}[sl(2)] Temperley-Lieb model. A systematic computation method is used to constructed the solutions of the boundary Yang-Baxter equations. For ss half-integer, a general 2s(s+1)+3/22s(s+1)+3/2 free parameter solution is presented. It turns that for ss integer, the general solution has 2s(s+1)+12s(s+1)+1 free parameters. Moreover, some particular solutions are discussed.Comment: LaTex 17 page
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