41 research outputs found

    Multiphoton Ionization as Time-Dependent Tunneling

    Get PDF
    A new semiclassical approach to ionization by an oscillating field is presented. For a delta-function atom, an asymptotic analysis is performed with respect to a quantity h, defined as the ratio of photon energy to ponderomotive energy. This h appears formally equivalent to Planck's constant in a suitably transformed Schroedinger equation and allows semiclassical methods to be applicable. Systematically, a picture of tunneling wave packets in complex time is developped, which by interference account for the typical ponderomotive features of ionization curves. These analytical results are then compared to numerical simulations and are shown to be in good agreement.Comment: 36 pages (also printable half size), uuencoded compressed tarred Latex file with 9 Postscript figures included automaticall

    Quantum Tunneling in the Wigner Representation

    Get PDF
    Time dependence for barrier penetration is considered in the phase space. An asymptotic phase-space propagator for nonrelativistic scattering on a one - dimensional barrier is constructed. The propagator has a form universal for various initial state preparations and local potential barriers. It is manifestly causal and includes time-lag effects and quantum spreading. Specific features of quantum dynamics which disappear in the standard semi-classical approximation are revealed. The propagator may be applied to calculation of the final momentum and coordinate distributions, for particles transmitted through or reflected from the potential barrier, as well as for elucidating the tunneling time problem.Comment: 18 pages, LATEX, no figure

    A critical review of the research literature on Six Sigma, Lean and StuderGroup's Hardwiring Excellence in the United States: the need to demonstrate and communicate the effectiveness of transformation strategies in healthcare

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>U.S. healthcare organizations are confronted with numerous and varied transformational strategies promising improvements along all dimensions of quality and performance. This article examines the peer-reviewed literature from the U.S. for evidence of effectiveness among three current popular transformational strategies: Six Sigma, Lean/Toyota Production System, and Studer's Hardwiring Excellence.</p> <p>Methods</p> <p>The English language health, healthcare management, and organizational science literature (up to December 2007) indexed in Medline, Web of Science, ABI/Inform, Cochrane Library, CINAHL, and ERIC was reviewed for studies on the aforementioned transformation strategies in healthcare settings. Articles were included if they: appeared in a peer-reviewed journal; described a specific intervention; were not classified as a pilot study; provided quantitative data; and were not review articles. Nine references on Six Sigma, nine on Lean/Toyota Production System, and one on StuderGroup meet the study's eligibility criteria.</p> <p>Results</p> <p>The reviewed studies universally concluded the implementations of these transformation strategies were successful in improving a variety of healthcare related processes and outcomes. Additionally, the existing literature reflects a wide application of these transformation strategies in terms of both settings and problems. However, despite these positive features, the vast majority had methodological limitations that might undermine the validity of the results. Common features included: weak study designs, inappropriate analyses, and failures to rule out alternative hypotheses. Furthermore, frequently absent was any attention to changes in organizational culture or substantial evidence of lasting effects from these efforts.</p> <p>Conclusion</p> <p>Despite the current popularity of these strategies, few studies meet the inclusion criteria for this review. Furthermore, each could have been improved substantially in order to ensure the validity of the conclusions, demonstrate sustainability, investigate changes in organizational culture, or even how one strategy interfaced with other concurrent and subsequent transformation efforts. While informative results can be gleaned from less rigorous studies, improved design and analysis can more effectively guide healthcare leaders who are motivated to transform their organizations and convince others of the need to employ such strategies. Demanding more exacting evaluation of projects consultants, or partnerships with health management researchers in academic settings, can support such efforts.</p

    Attaining composure through breath-awareness: a phenomenological account of the use of the breath in social work

    Get PDF
    This article is the first to address breathing in social work directly. It sits within the phenomenological tradition and as such provides accounts from social work education and practice as a means of recognizing a commonality of experience. The article argues for a considered, conscious use of the breath in order for the social worker to gain a state of calm or composure and also to be able to foster composure in others – the so called “circle of breath”. The focus is on the skills of the worker but also on the meanings of the choices they make. A phenomenological approach to the topic of composure is contrasted with a psychotherapeutic approach. No particular method is advocated although several exercises designed to aid breath awareness are suggested. A discussion is threaded throughout on the relationship between the breath and spirituality in social work, also considered in phenomenological terms

    Therapeutisierung als Optimierung? Zum Diskurs von Psychotherapie, Beratung und Coaching seit Ende der 1960er

    No full text
    Elberfeld J. Therapeutisierung als Optimierung? Zum Diskurs von Psychotherapie, Beratung und Coaching seit Ende der 1960er. In: Sabisch K, Sieben A, Straub J, eds. Optimierungen des Humanen. Kulturelle, soziale und psychische Schattenseiten“ wissenschaftlich-technischer Innovation und praktischer Normierungen des Menschen. Bielefeld: Transcript; In Press
    corecore