3,023 research outputs found

    Identifying the causal mechanisms of the quiet eye

    Get PDF
    Scientists who have examined the gaze strategies employed by athletes have determined that longer quiet eye (QE) durations (QED) are characteristic of skilled compared to less-skilled performers. However, the cognitive mechanisms of the QE and, specifically, how the QED affects performance are not yet fully understood. We review research that has examined the functional mechanism underlying QE and discuss the neural networks that may be involved. We also highlight the limitations surrounding QE measurement and its definition and propose future research directions to address these shortcomings. Investigations into the behavioural and neural mechanisms of QE will aid the understanding of the perceptual and cognitive processes underlying expert performance and the factors that change as expertise develops

    The limiting behavior of solutions to p-Laplacian problems with convection and exponential terms

    Full text link
    We consider, for a,l≥1,a,l\geq1, b,s,α>0,b,s,\alpha>0, and p>q≥1,p>q\geq1, the homogeneous Dirichlet problem for the equation −Δpu=λuq−1+βua−1∣∇u∣b+mtl−1eαts-\Delta_{p}u=\lambda u^{q-1}+\beta u^{a-1}\left\vert \nabla u\right\vert ^{b}+mt^{l-1}e^{\alpha t^{s}} in a smooth bounded domain Ω⊂RN.\Omega\subset\mathbb{R}^{N}. We prove that under certain setting of the parameters λ,\lambda, β\beta and mm the problem admits at least one positive solution. Using this result we prove that if λ,β>0\lambda,\beta>0 are arbitrarily fixed and mm is sufficiently small, then the problem has a positive solution up,u_{p}, for all pp sufficiently large. In addition, we show that upu_{p} converges uniformly to the distance function to the boundary of Ω,\Omega, as p→∞.p\rightarrow\infty. This convergence result is new for nonlinearities involving a convection term.Comment: 18 page

    Assessing the image quality of pelvic MR images acquired with a flat couch for radiotherapy treatment planning

    Get PDF
    OBJECTIVES: To improve the integration of MRI with radiotherapy treatment planning, our department fabricated a flat couch top for our MR scanner. Setting up using this couch top meant that the patients were physically higher up in the scanner and, posteriorly, a gap was introduced between the patient and radiofrequency coil. METHODS: Phantom measurements were performed to assess the quantitative impact on image quality. A phantom was set up with and without the flat couch insert in place, and measurements of image uniformity and signal to noise were made. To assess clinical impact, six patients with pelvic cancer were recruited and scanned on both couch types. The image quality of pairs of scans was assessed by two consultant radiologists. RESULTS: The use of the flat couch insert led to a drop in image signal to noise of approximately 14%. Uniformity in the anteroposterior direction was affected the most, with little change in right-to-left and feet-to-head directions. All six patients were successfully scanned on the flat couch, although one patient had to be positioned with their arms by their sides. The image quality scores showed no statistically significant change between scans with and without the flat couch in place. CONCLUSION: Although the quantitative performance of the coil is affected by the integration of a flat couch top, there is no discernible deterioration of diagnostic image quality, as assessed by two consultant radiologists. Although the flat couch insert moved patients higher in the bore of the scanner, all patients in the study were successfully scanned

    Continuity and Change: The Mexicana Experience with Health and Healing in Iowa

    Get PDF
    Rapid growth in Iowa\u27s Latino immigrant population has presented challenges for health care providers. Of principal concern are the health disparities between newcomer Latinos and established-resident Iowans and if these disparities result from a lack of access to health care or the inability of Iowa health care providers to accommodate the unique practices and perceptions of newcomer patients. The purpose of this article is to address this issue through the experience of Mexican women who have migrated to Iowa and interacted to varying degrees with health care providers. In addition to addressing issues of access and the newcomers\u27 perceptions of the cultural competence of health providers, we also explore the role that traditional or folk medicine plays in the overall access to healthcare in Iowa

    Transient, unsettling and creative space: Experiences of liminality through the accounts of Chinese students on a UK-based MBA

    Get PDF
    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ The Author(s) 2009.This article explores the experiences of liminality through the accounts of Chinese students on a UK-based MBA programme. The transient nature of the MBA experience, as well as the international status of the Chinese student, is resonant with conceptualizations of liminality as ‘in between’ space. Based on semi-structured interviews with 20 MBA graduates who had subsequently returned to China with their qualification, we explored their perceptions of outcomes from the course and their experiences as international students on a programme imbued with western norms and values. Results support the unsettling yet creative implications of liminality, as well as the fragmented insecure nature of identities, as individuals pass through the MBA ‘rite of passage’ in terms of ‘becoming’ a manager and entering a new phase of career. Accounts suggest the creation of hierarchical structures within liminal space whereby Chinese students, through their positioning at the margin, have uncomfortable yet illuminating encounters with alterity. At the same time, they experience levels of ambiguity and uncertainty in the post-liminal phase of China-located employments, as new western-based managerial identities collide with dominant discourses of Chinese organization

    Octahedral Tilt Instability of ReO_3-type Crystals

    Full text link
    The octahedron tilt transitions of ABX_3 perovskite-structure materials lead to an anti-polar (or antiferroelectric) arrangement of dipoles, with the low temperature structure having six sublattices polarized along various crystallographic directions. It is shown that an important mechanism driving the transition is long range dipole-dipole forces acting on both displacive and induced parts of the anion dipole. This acts in concert with short range repulsion, allowing a gain of electrostatic (Madelung) energy, both dipole-dipole and charge-charge, because the unit cell shrinks when the hard ionic spheres of the rigid octahedron tilt out of linear alignment.Comment: 4 page with 3 figures included; new version updates references and clarifies the argument
    • …
    corecore