703 research outputs found

    Application of assessment metrics for an academic department faculty development program

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    Faculty development is increasingly seen as a cornerstone of career sustainability in academic medicine, pediatrics, and other disciplines. Many current senior academic medical faculty developed their careers in systems that are distinctly different from current paradigms. Multiple internal and external variables have caused the academic environment to transform. These variables include rapidly changing technology, the opening of the academy to public scrutiny, external rankings, changes in the opportunities for academic advancement (including the increasing predominance of non–tenure track faculty), sharp reductions in protected time for teaching, increased pressure to meet measurable benchmarks for academic and financial productivity, and an increased emphasis on multidisciplinary team science to more rapidly advance biomedical research. Faculty must also become adept at assessing learning outcomes, and engaging in collaborative projects that couple scholarly expertise with the local, national, or international communities. The increasing incidence of burnout and other sequelae of chronic stress among medical faculty is well documented and has led to recommendations for more formalized institutional attention to these threats to the academic medical enterprise

    Breaking of general rotational symmetries by multi-dimensional classical ratchets

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    We demonstrate that a particle driven by a set of spatially uncorrelated, independent colored noise forces in a bounded, multidimensional potential exhibits rotations that are independent of the initial conditions. We calculate the particle currents in terms of the noise statistics and the potential asymmetries by deriving an n-dimensional Fokker-Planck equation in the small correlation time limit. We analyze a variety of flow patterns for various potential structures, generating various combinations of laminar and rotational flows.Comment: Accepted, Physical Review

    Survey of nucleon electromagnetic form factors

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    A dressed-quark core contribution to nucleon electromagnetic form factors is calculated. It is defined by the solution of a Poincare' covariant Faddeev equation in which dressed-quarks provide the elementary degree of freedom and correlations between them are expressed via diquarks. The nucleon-photon vertex involves a single parameter; i.e., a diquark charge radius. It is argued to be commensurate with the pion's charge radius. A comprehensive analysis and explanation of the form factors is built upon this foundation. A particular feature of the study is a separation of form factor contributions into those from different diagram types and correlation sectors, and subsequently a flavour separation for each of these. Amongst the extensive body of results that one could highlight are: r_1^{n,u}>r_1^{n,d}, owing to the presence of axial-vector quark-quark correlations; and for both the neutron and proton the ratio of Sachs electric and magnetic form factors possesses a zero.Comment: 43 pages, 17 figures, 12 tables, 5 appendice

    Quark Imaging in the Proton Via Quantum Phase-Space Distributions

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    We develop the concept of quantum phase-space (Wigner) distributions for quarks and gluons in the proton. To appreciate their physical content, we analyze the contraints from special relativity on the interpretation of elastic form factors, and examine the physics of the Feynman parton distributions in the proton's rest frame. We relate the quark Wigner functions to the transverse-momentum dependent parton distributions and generalized parton distributions, emphasizing the physical role of the skewness parameter. We show that the Wigner functions allow to visualize quantum quarks and gluons using the language of the classical phase space. We present two examples of the quark Wigner distributions and point out some model-independent features.Comment: 20 pages with 3 fiture

    Between Boston and Berlin: American MNCs and the shifting contours of industrial relations in Ireland

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    peer-reviewedDrawing on detailed qualitative case studies and utilizing a national business system lens, we explore a largely underrepresented debate in the literature, namely the nature of change in a specific but critical element of business systems, that is the industrial relations (IR) institutions of the State and the impact of MNCs thereon. Given the critical mass of US investment in Ireland, we examine how US MNCs manage IR in their Irish subsidiaries, how the policies and practices they pursue have impacted on the Irish IR system, and more broadly their role in shaping the host institutional environment. Overall, we conclude that there is some evidence of change in the IR system, change that we trace indirectly to the US MNC sector. Further, the US MNC sector displays evidence of elements of the management of IR that is clearly at odds with Irish traditions. Thus, in these firms we point to the emergence of a hybrid system of the management of IR and the establishment of new traditions more reflective of US business system.ACCEPTEDpeer-reviewe

    Overall and abdominal obesity and prostate cancer risk in a West African population: An analysis of the Ghana Prostate Study

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    Obesity has been associated with an increased risk of advanced prostate cancer. However, most studies have been conducted among North American and European populations. Prostate cancer mortality appears elevated in West Africa, yet risk factors for prostate cancer in this region are unknown. We thus examined the relationship between obesity and prostate cancer using a case-control study conducted in Accra, Ghana in 2004 to 2012. Cases and controls were drawn from a population-based sample of 1037 men screened for prostate cancer, yielding 73 cases and 964 controls. An additional 493 incident cases were recruited from the Korle-Bu Teaching Hospital. Anthropometric measurements were taken at enrollment. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR) and prostate cancer, adjusting for potential confounders. The mean BMI was 25.1 kg/m2 for cases and 24.3 kg/m2 for controls. After adjustment, men with BMI ≄ 30 kg/m2 had an increased risk of prostate cancer relative to men with BMI < 25 kg/m2 (OR 1.86, 95% CI 1.11-3.13). Elevated WC (OR 1.76, 95% CI 1.24-2.51) and WHR (OR 1.46, 95% CI 0.99-2.16) were also associated with prostate cancer. Associations were not modified by smoking status and were evident for low- and high-grade disease. These findings indicate that overall and abdominal obesity are positively associated with prostate cancer among men in Ghana, implicating obesity as a potentially modifiable risk factor for prostate cancer in this region

    Nucleon and hadron structure changes in the nuclear medium and impact on observables

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    We review the effect of hadron structure changes in a nuclear medium using the quark-meson coupling (QMC) model, which is based on a mean field description of non-overlapping nucleon (or baryon) bags bound by the self-consistent exchange of scalar and vector mesons. This approach leads to simple scaling relations for the changes of hadron masses in a nuclear medium. It can also be extended to describe finite nuclei, as well as the properties of hypernuclei and meson-nucleus deeply bound states. It is of great interest that the model predicts a variation of the nucleon form factors in nuclear matter. We also study the empirically observed, Bloom-Gilman (quark-hadron) duality. Other applications of the model include subthreshold kaon production in heavy ion collisions, D and D-bar meson production in antiproton-nucleus collisions, and J/Psi suppression. In particular, the modification of the D and D-bar meson properties in nuclear medium can lead to a large J/Psi absorption cross section, which explains the observed J/Psi suppression in relativistic heavy ion collisions.Comment: 143 pages, 77 figures, references added, a review article accepted in Prog. Part. Nucl. Phy

    Smoothed Particle Hydrodynamics (SPH) modelling of transient heat transfer in pulsed laser ablation of Al and associated free-surface problems

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    A Smoothed Particle Hydrodynamics (SPH) numerical model is developed to simulate pulsed-laser ablation processes for micro-machining. Heat diffusion behaviour of a specimen under the action of nanosecond pulsed lasers can be described analytically by using complementary error function solutions of second-order differential equations. However, their application is limited to cases without loss of material at the surface. Compared to conventional mesh-based techniques, as a novel meshless simulation method, SPH is ideally suited to applications with highly non-linear and explosive behaviour in laser ablation. However, little is known about the suitability of using SPH for the modelling of laser-material interactions with multiple phases at the micro scale. The present work investigates SPH modelling of pulsed-laser ablation of aluminium where the laser is applied directly to the free-surface boundary of the specimen. Having first assessed the performance of standard SPH surface treatments for functions commonly used to describe laser heating, the heat conduction behaviour of a new SPH methodology is then evaluated through a number of test cases for single- and multiple-pulse laser heating of aluminium showing excellent agreement when compared with an analytical solution. Simulation of real ablation processes, however, requires the model to capture the removal of material from the surface and its subsequent effects on the laser heating process. Hence, the SPH model for describing the transient behaviour of nanosecond laser ablation is validated with a number of experimental and reference results reported in the literature. The SPH model successfully predicts the material ablation depth profiles over a wide range of laser fluences 4–23 J/cm2 and pulse durations 6–10 ns, and also predicts the transient behaviour of the ejected material during the laser ablation process. Unlike conventional mesh-based methods, the SPH model was not only able to provide the thermo-physical properties of the ejected particles, but also the effect of the interaction between them as well as the direction and the pattern of the ejection
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