3,233 research outputs found

    A three dimensional vortex wake model for missiles at high angles on attack

    Get PDF
    A three dimensional model for the steady flow past missile and aircraft nose shaped bodies is presented based on augmenting a potential solution with a wake composed of vortex filaments. The vortex positions are determined by the requirement that they, in some sense, align with the flow. The aerodynamic loads on the body are compared with experimental values and used to evaluate the model. The vortex positions compare well with flow visualization results for slender bodies at high angles of attack. The approximations in the wake near the body cause peaks in the force distributions more severe than in the measured values. For given vortex strengths and body attachment points multiple steady vortex positions were not found

    Brief report: Self-compassion, physical health and the mediating role of health-promoting behaviours.

    Get PDF
    To test the hypothesis that self-compassion predicts better physical health and that this is partially mediated through health-promoting behaviours, 147 adults completed self-report measures of self-compassion, health-promoting behaviours and physical health. Self-compassion and health-promoting behaviours were negatively associated with physical symptom scores. Self-compassion was positively associated with health-promoting behaviours. A bootstrapped mediation model confirmed a significant direct effect of self-compassion on physical health through health-promoting behaviours (R(2) = 0.13, b = -8.98, p = 0.015), which was partially mediated through health-promoting behaviours (R(2) = 0.06, b = -3.16, 95 per cent confidence interval [-6.78, -0.86]). Findings underscore the potential health-promoting benefits of self-compassion

    Using a Gridded Global Dataset to Characterize Regional Hydroclimate in Central Chile

    Get PDF
    Central Chile is facing dramatic projections of climate change, with a consensus for declining precipitation, negatively affecting hydropower generation and irrigated agriculture. Rising from sea level to 6000 m within a distance of 200 km, precipitation characterization is difficult because of a lack of long-term observations, especially at higher elevations. For understanding current mean and extreme conditions and recent hydroclimatological change, as well as to provide a baseline for downscaling climate model projections, a temporally and spatially complete dataset of daily meteorology is essential. The authors use a gridded global daily meteorological dataset at 0.25° resolution for the period 1948–2008, adjusted by monthly precipitation observations interpolated to the same grid using a cokriging method with elevation as a covariate. For validation, daily statistics of the adjusted gridded precipitation are compared to station observations. For further validation, a hydrology model is driven with the gridded 0.25° meteorology and streamflow statistics are compared with observed flow. The high elevation precipitation is validated by comparing the simulated snow extent to Moderate Resolution Imaging Spectroradiometer (MODIS) images. Results show that the daily meteorology with the adjusted precipitation can accurately capture the statistical properties of extreme events as well as the sequence of wet and dry events, with hydrological model results displaying reasonable agreement with observed streamflow and snow extent. This demonstrates the successful use of a global gridded data product in a relatively data-sparse region to capture hydroclimatological characteristics and extremes

    Popular music, psychogeography, place identity and tourism: The case of Sheffield

    Get PDF
    Tourism and cultural agencies in some English provincial cities are promoting their popular music ‘heritage’ and, in some cases, contemporary musicians through the packaging of trails, sites, ‘iconic’ venues and festivals. This article focuses on Sheffield, a ‘post-industrial’ northern English city which is drawing on its associations with musicians past and present in seeking to attract tourists. This article is based on interviews with, among others, recording artists, promoters, producers and venue managers, along with reflective observational and documentary data. Theoretical remarks are made on the representations of popular musicians through cultural tourism strategies, programmes and products and also on the ways in which musicians convey a ‘psychogeographical’ sense of place in the ‘soundscape’ of the city

    Fluctuations for the Ginzburg-Landau ∇ϕ\nabla \phi Interface Model on a Bounded Domain

    Full text link
    We study the massless field on Dn=D∩1nZ2D_n = D \cap \tfrac{1}{n} \Z^2, where D⊆R2D \subseteq \R^2 is a bounded domain with smooth boundary, with Hamiltonian \CH(h) = \sum_{x \sim y} \CV(h(x) - h(y)). The interaction \CV is assumed to be symmetric and uniformly convex. This is a general model for a (2+1)(2+1)-dimensional effective interface where hh represents the height. We take our boundary conditions to be a continuous perturbation of a macroscopic tilt: h(x)=nx⋅u+f(x)h(x) = n x \cdot u + f(x) for x∈∂Dnx \in \partial D_n, u∈R2u \in \R^2, and f ⁣:R2→Rf \colon \R^2 \to \R continuous. We prove that the fluctuations of linear functionals of h(x)h(x) about the tilt converge in the limit to a Gaussian free field on DD, the standard Gaussian with respect to the weighted Dirichlet inner product (f,g)∇ÎČ=∫D∑iÎČi∂ifi∂igi(f,g)_\nabla^\beta = \int_D \sum_i \beta_i \partial_i f_i \partial_i g_i for some explicit ÎČ=ÎČ(u)\beta = \beta(u). In a subsequent article, we will employ the tools developed here to resolve a conjecture of Sheffield that the zero contour lines of hh are asymptotically described by SLE(4)SLE(4), a conformally invariant random curve.Comment: 58 page

    A simple method for finite range decomposition of quadratic forms and Gaussian fields

    Full text link
    We present a simple method to decompose the Green forms corresponding to a large class of interesting symmetric Dirichlet forms into integrals over symmetric positive semi-definite and finite range (properly supported) forms that are smoother than the original Green form. This result gives rise to multiscale decompositions of the associated Gaussian free fields into sums of independent smoother Gaussian fields with spatially localized correlations. Our method makes use of the finite propagation speed of the wave equation and Chebyshev polynomials. It improves several existing results and also gives simpler proofs.Comment: minor correction for t<

    Mapping, Meeting and Modulating Stress and Emotion: Combining Mindfulness and the Workable Ranges Model

    Get PDF
    This article examines the practice of combining explorations of regulated and dysregulated states through the Workable Ranges Model (WRM) with the skills and qualities taught in Mindfulness-Based Stress Reduction (MBSR). MBSR was designed to help participants to self-regulate stress. Didactic teaching about stress reactivity is part of the curriculum and may contribute to positive outcomes. A practice-based embodied methodology utilised mindful inquiry in research methods. Seven graduates of MBSR courses that included the WRM became conceptual encounter research partners. Following a re-presentation of the WRM, data were gathered through a diagrammatic diary exercise, post-meditation inquiry and a group discussion. Reflexive thematic analysis identified an overarching theme that the WRM was a dynamic map for exploring stability and stress. Two non-hierarchical themes articulated interrelated self-reflective activities associated with using the WRM as a map. Mapping involved charting regulated and dysregulated embodied experience. Meeting was the embodied application to mindfulness practice. Modulating states through intentional orienting to and resourcing mindful self-regulation and self-care grew out of the mapping and meeting practices. The WRM provided a form and set of words to name mind-body states, and to develop and apply insights about them. The WRM was used to shape new meanings about the relationship between mindfulness and regulated and dysregulated experience. This is theorised through its connection with embodied metaphors. The combination of the WRM and mindfulness worked to frame and progress mindful self-regulation. The WRM may be a valuable resource for mindfulness teachers to support self-regulation and mental health

    Postpartum sterilization choices made by HIV-infected women.

    Get PDF
    OBJECTIVE: To assess if HIV-infected women made different choices for postpartum sterilization after implementation of the Pediatric AIDS Clinical Trials Group protocol 076 (November 1, 1994) compared to before implementation. STUDY DESIGN: A retrospective cohort study in which medical records were reviewed to obtain demographic, obstetric and HIV-related data from January 1993 through December 2002. HIV-infected women who completed a pregnancy by birth or abortion were divided into two comparison groups: "Pre-076" and "Post-076". The primary outcome was sterilization by postpartum tubal ligation.Results. Forty-two women (74%) in the Pre-076 group chose sterilization compared to 139 of 310 women (45%) in the Post-076 group (unadjusted OR 3.44, 95% CI 1.83, 6.47). Seventy-one percent of women younger than 21 years of age in the Pre-076 Group chose sterilization compared with only 35% of women younger than 21 years in the Post-076 group (p = 0.0136). Similarly, 78% of primiparous women chose sterilization after their first pregnancy in the Pre-076 group, compared to 14% in the Post-076 group (p < 0.001). CONCLUSIONS: Since the implementation of PACTG 076 protocol in November 1994, fewer HIV-infected women chose postpartum sterilization. The typical woman who now chooses postpartum sterilization is less likely to be young or primiparous than those who chose sterilization before PACTG Protocol 076 implementation

    Spatial and Time Distribution of Dairy Cattle Manure in an Intensive Pasture System

    Get PDF
    This study determined distribution of feces and urine from dairy cattle managed in a rotationally grazed pasture. Lactating Holsteins (n=18) and Jerseys (n=18) were grazed on a .74 ha endophyte-free fescue (Festuca arundinacea)/white clover (Trifolium repens) pasture. All cows were constantly observed for 24 h 6 times over 12 mo. Cows had access to about 54% of the paddock during the first grazing period (12 h) and had access to the entire paddock during the second grazing period (8 h). Data included: (1) all feces and urine events from eight cows, observed while in the pasture, feed area, milking parlor or in transit; and (2) all urine and feces events on pasture for all 36 cows each grazing period. After each grazing period, urine (marked with color coded flags) and feces were surveyed and mapped. Data were transformed and then analyzed using statistical software. Percentages of the manure events were highly correlated with time spent in each area (r= .99). Feces and urine (estimated at .12 m2 and .36 m2, respectively) from the six 24-hr observations covered 10% of the total paddock. Within a 30-m radius of the water tank, spatial density of feces and urine from the warm season observations (July, August, September) were significantly greater than concentrations during the cool season observations (December, February, and April). Pasture systems can potentially reduce manure handling and storage requirements proportional to the time cows are kept on pasture. Manure on pasture was relatively evenly distributed over multiple grazing periods

    On the spatial Markov property of soups of unoriented and oriented loops

    Full text link
    We describe simple properties of some soups of unoriented Markov loops and of some soups of oriented Markov loops that can be interpreted as a spatial Markov property of these loop-soups. This property of the latter soup is related to well-known features of the uniform spanning trees (such as Wilson's algorithm) while the Markov property of the former soup is related to the Gaussian Free Field and to identities used in the foundational papers of Symanzik, Nelson, and of Brydges, Fr\"ohlich and Spencer or Dynkin, or more recently by Le Jan
    • 

    corecore