1,922 research outputs found

    Social Functioning: A Sociological Common Base for Social Work Practice

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    This article describes the experience of a social work mental health agency with Social Role Theory (SRT), that is an organizing concept for the delivery of its assessment and treatment program. SRT has been called the process variable of the program, meaning how services are delivered. Social functioning, a concept taken from SRT, is a treatment outcome. The overall purposes of the article are to describe the contribution of sociology to social work practice, and to advance the argument that social functioning is a common base for social work practice generally

    High country river processes : a technical discussion of results from research on the Kowai River system, Springfield, Canterbury

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    A sub-catchment (Torlesse Stream) of the Kowai River, Canterbury, has been the site of an interdisciplinary study of the relationships between erosion and stream sedimentation (Hayward 1975). It was logical to extend the stream sediment investigation of that study (Hayward 1978) into the Kowai system proper in order to establish changes in the nature and distribution of the stream sediments with distance downstream. The sediment sampling study, comprising Part I of Paper A in this volume, analyses the changes in size, distribution, form and rock type of the river gravels from ahead water mountain stream to the wide braided river beds of the middle reaches of the Kowai River. Part 2 of Paper A discusses the possible implications for the management that these sediment studies have for this and other similar river systems. It is believed that if thought necessary it is possible to design a river training programme to guide the river towards a more manageable pattern. Paper B of this volume compares the results of the present river gravel survey with those from a sedimentological analysis of fluvio-glacial outwash gravels deposited several thousand years ago within the lower reaches of the Kowai system. This comparative study is used to indicate differences in the hydrologic environment prevailing at their respective times of deposition, and aids in our understanding of the processes at work in hill and high country rivers today. Both Papers A and B relate to the Kowai River system, but the authors wish to emphasise that the findings from these studies are believed to have application to other similar gravel bed river systems

    Self-diffusion on metal surfaces

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    Abstract Not Provided

    Controlling Fast Chaos in Delay Dynamical Systems

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    We introduce a novel approach for controlling fast chaos in time-delay dynamical systems and use it to control a chaotic photonic device with a characteristic time scale of ~12 ns. Our approach is a prescription for how to implement existing chaos control algorithms in a way that exploits the system's inherent time-delay and allows control even in the presence of substantial control-loop latency (the finite time it takes signals to propagate through the components in the controller). This research paves the way for applications exploiting fast control of chaos, such as chaos-based communication schemes and stabilizing the behavior of ultrafast lasers.Comment: 4 pages, 4 figures, to be published in Physical Review Letter

    Kinetics of Surface Enrichment: A Molecular Dynamics Study

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    We use molecular dynamics (MD) to study the kinetics of surface enrichment (SE) in a stable homogeneous mixture (AB), placed in contact with a surface which preferentially attracts A. The SE profiles show a characteristic double-exponential behavior with two length scales: \xi_-, which rapidly saturates to its equilibrium value, and \xi_+, which diverges as a power-law with time (\xi_+ \sim t^\theta). We find that hydrodynamic effects result in a crossover of the growth exponent from \theta \simeq 0.5 to \theta \simeq 1.0. There is also a corresponding crossover in the growth dynamics of the SE-layer thickness.Comment: 20 pages, 6 figures, Published in J. Chem. Phys. (Research Highlights

    Anisotropic diffusion in continuum relaxation of stepped crystal surfaces

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    We study the continuum limit in 2+1 dimensions of nanoscale anisotropic diffusion processes on crystal surfaces relaxing to become flat below roughening. Our main result is a continuum law for the surface flux in terms of a new continuum-scale tensor mobility. The starting point is the Burton, Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps whose motion drives surface evolution. Our derivation is based on the separation of local space variables into fast and slow. The model includes: (i) anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps; (ii) diffusion of atoms along step edges; and (iii) attachment-detachment of atoms at step edges. We derive a parabolic fourth-order, fully nonlinear partial differential equation (PDE) for the continuum surface height profile. An ingredient of this PDE is the surface mobility for the adatom flux, which is a nontrivial extension of the tensor mobility for isotropic terrace diffusion derived previously by Margetis and Kohn. Approximate, separable solutions of the PDE are discussed.Comment: 14 pages, 1 figur

    Trends in absolute socioeconomic inequalities in mortality in Sweden and New Zealand. A 20-year gender perspective

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    BACKGROUND: Both trends in socioeconomic inequalities in mortality, and cross-country comparisons, may give more information about the causes of health inequalities. We analysed trends in socioeconomic differentials by mortality from early 1980s to late 1990s, comparing Sweden with New Zealand. METHODS: The New Zealand Census Mortality Study (NZCMS) consisting of over 2 million individuals and the Swedish Survey of Living Conditions (ULF) comprising over 100, 000 individuals were used for analyses. Education and household income were used as measures of socioeconomic position (SEP). The slope index of inequality (SII) was calculated to estimate absolute inequalities in mortality. Analyses were based on 3–5 year follow-up and limited to individuals aged 25–77 years. Age standardised mortality rates were calculated using the European population standard. RESULTS: Absolute inequalities in mortality on average over the 1980s and 1990s for both men and women by education were similar in Sweden and New Zealand, but by income were greater in Sweden. Comparing trends in absolute inequalities over the 1980s and 1990s, men's absolute inequalities by education decreased by 66% in Sweden and by 17% in New Zealand (p for trend <0.01 in both countries). Women's absolute inequalities by education decreased by 19% in Sweden (p = 0.03) and by 8% in New Zealand (p = 0.53). Men's absolute inequalities by income decreased by 51% in Sweden (p for trend = 0.06), but increased by 16% in New Zealand (p = 0.13). Women's absolute inequalities by income increased in both countries: 12% in Sweden (p = 0.03) and 21% in New Zealand (p = 0.04). CONCLUSION: Trends in socioeconomic inequalities in mortality were clearly most favourable for men in Sweden. Trends also seemed to be more favourable for men than women in New Zealand. Assuming the trends in male inequalities in Sweden were not a statistical chance finding, it is not clear what the substantive reason(s) was for the pronounced decrease. Further gender comparisons are required

    X-Ray Synchrotron White Beam Excitation of Auger Electrons

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    Auger electron spectra have been measured at the Cornell High Energy Synchrotron Source (CHESS), using the full white beam x-ray spectrum as the excitation source. Ordinary Auger spectra obtained in the laboratory with an electron beam source must employ derivative techniques to distinguish the Auger structures from the large background due to the excitation beam. The synchrotron white beam eliminates this source of background and produces signal rates as high as 107 cps. Superior signal-to-background ratios are found for Auger peaks above a few hundred eV, and count rates are large enough to suggest microprobe applications. X-ray induced Auger satellite peaks were observed with intensities much greater than the electron-induced counterpart; this anomaly is not completely understood

    Single particle multipole expansions from Micromagnetic Tomography

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    Micromagnetic tomography aims at reconstructing large numbers of individual magnetizations of magnetic particles from combining high-resolution magnetic scanning techniques with micro X-ray computed tomography (microCT). Previous work demonstrated that dipole moments can be robustly inferred, and mathematical analysis showed that the potential field of each particle is uniquely determined. Here, we describe a mathematical procedure to recover higher orders of the magnetic potential of the individual magnetic particles in terms of their spherical harmonic expansions (SHE). We test this approach on data from scanning superconducting quantum interference device microscopy and microCT of a reference sample. For particles with high signal-to-noise ratio of the magnetic scan we demonstrate that SHE up to order n=3n=3 can be robustly recovered. This additional level of detail restricts the possible internal magnetization structures of the particles and provides valuable rock magnetic information with respect to their stability and reliability as paleomagnetic remanence carriers. Micromagnetic tomography therefore enables a new approach for detailed rock magnetic studies on large ensembles of individual particles.Comment: 21 pages, 4 Figures, 3 Tables. For Supplemental Material see "Ancillary files" in this arxiv websit
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