19,541 research outputs found

    Summer snow extent heralding of the winter North Atlantic Oscillation

    Get PDF
    [1] Winter climate over the North Atlantic and European sector is modulated by the North Atlantic Oscillation (NAO). We find that the summer extent of snow cover over northern North America and northern Eurasia is linked significantly (p < 0.01) to the upcoming winter NAO state. Summers with high/low snow extent precede winters of low/high NAO index phase. We suggest the linkage arises from the summer snow-associated formation of anomalous longitudinal differences in surface air temperature with the subpolar North Atlantic. Our findings indicate the seasonal predictability of North Atlantic winter climate may be higher and extend to longer leads than thought previously

    Diffusive benefits of cylinders in front of a Schroeder diffuser

    Get PDF
    A numerical investigation is performed into the diffusive effects of cylinders positioned in front of a Schroeder diffuser. A regular line of cylinders is shown to offer notable improvements to diffusion from a periodic Schroeder device, provided lateral cylinder spacing is incommensurable with the Schroeder period width. Further investigation considers angular dependence and low frequency results in greater detail, as well as the effects on narrowband and modulated Schroeder devices. An optimization procedure is subsequently performed to investigate the effects of an irregular cylinder arrangement, which provides further diffusive benefits. (C) 2010 Acoustical Society of America

    A Bayesian localised conditional auto-regressive model for estimating the health effects of air pollution

    Get PDF
    Estimation of the long-term health effects of air pollution is a challenging task, especially when modeling spatial small-area disease incidence data in an ecological study design. The challenge comes from the unobserved underlying spatial autocorrelation structure in these data, which is accounted for using random effects modeled by a globally smooth conditional autoregressive model. These smooth random effects confound the effects of air pollution, which are also globally smooth. To avoid this collinearity a Bayesian localized conditional autoregressive model is developed for the random effects. This localized model is flexible spatially, in the sense that it is not only able to model areas of spatial smoothness, but also it is able to capture step changes in the random effects surface. This methodological development allows us to improve the estimation performance of the covariate effects, compared to using traditional conditional auto-regressive models. These results are established using a simulation study, and are then illustrated with our motivating study on air pollution and respiratory ill health in Greater Glasgow, Scotland in 2011. The model shows substantial health effects of particulate matter air pollution and nitrogen dioxide, whose effects have been consistently attenuated by the currently available globally smooth models

    Impact of childhood experience and adult well-being on eating preferences and behaviours

    Get PDF
    OBJECTIVES: To examine the relative contribution of childhood experience, measured by childhood violence and childhood happiness, and adult well-being on adult eating preferences and behaviours, independent of proximal factors such as current deprivation. DESIGN: A cross-sectional, stratified, randomised sample survey using retrospective measures of childhood violence and happiness and self-reported measures of current well-being. SETTING: The North West Region of England between September 2012 and March 2013. PARTICIPANTS: Individuals aged 18–95-year-olds from randomly selected households (participation was successful for 90% of eligible households and 78% of the total visited addresses; n=11 243). OUTCOMES: Dichotomised measures for preference of healthy foods or ‘feel good’ foods and low or high daily fruit and vegetable consumption. RESULTS: After correcting for demographics, combined categories for childhood experience and dichotomised measures of adult well-being were found to be significantly related to adult food preferences and eating behaviours. Participants with unhappy and violent childhoods compared to those with happy and non-violent childhoods had adjusted ORs (95% CI, significance) of 2.67 (2.15 to 3.06, p<0.001) of having low daily fruit and vegetable intake (two or less portions) and 1.53 (1.29 to 1.81, p<0.001) of choosing ‘feel good’ foods over foods which were good for their long term health. CONCLUSIONS: Daily intake of fruit and vegetables, linked to non-communicable diseases, and preference for ‘feel good’ foods, linked to obesity, are affected by childhood experience and adult well-being independent of demographic factors. Preventative interventions which support parent–child relationships and improve childhood experience are likely to reduce the development of poor dietary and other health-risk behaviours

    Crystal field analysis of Dy and Tm implanted silicon for photonic and quantum technologies

    Get PDF
    We report the lattice site and symmetry of optically active Dy3+ and Tm3+ implanted Si. Local symmetry was determined by fitting crystal field parameters (CFPs), corresponding to various common symmetries, to the ground state splitting determined by photoluminescence measurements. These CFP values were then used to calculate the splitting of every J manifold. We find that both Dy and Tm ions are in a Si substitution site with local tetragonal symmetry. Knowledge of rare-earth ion symmetry is important in maximising the number of optically active centres and for quantum technology applications where local symmetry can be used to control decoherence

    FXN promoter silencing in the humanized mouse model of Friedreich Ataxia

    Get PDF
    Background - Friedreich ataxia is caused by an expanded GAA triplet-repeat sequence in intron 1 of the FXN gene that results in epigenetic silencing of the FXN promoter. This silencing mechanism is seen in patient-derived lymphoblastoid cells but it remains unknown if it is a widespread phenomenon affecting multiple cell types and tissues. Methodology / Principal Findings - The humanized mouse model of Friedreich ataxia (YG8sR), which carries a single transgenic insert of the human FXN gene with an expanded GAA triplet-repeat in intron 1, is deficient for FXN transcript when compared to an isogenic transgenic mouse lacking the expanded repeat (Y47R). We found that in YG8sR the deficiency of FXN transcript extended both upstream and downstream of the expanded GAA triplet-repeat, suggestive of deficient transcriptional initiation. This pattern of deficiency was seen in all tissues tested, irrespective of whether they are known to be affected or spared in disease pathogenesis, in both neuronal and non-neuronal tissues, and in cultured primary fibroblasts. FXN promoter function was directly measured via metabolic labeling of newly synthesized transcripts in fibroblasts, which revealed that the YG8sR mouse was significantly deficient in transcriptional initiation compared to the Y47R mouse. Conclusions / Significance- Deficient transcriptional initiation accounts for FXN transcriptional deficiency in the humanized mouse model of Friedreich ataxia, similar to patient-derived cells, and the mechanism underlying promoter silencing in Friedreich ataxia is widespread across multiple cell types and tissues.This research was supported by grants from the National Institutes of Health (R01 NS072418), and the Muscular Dystrophy Association to S.I.B. Y.K.C. is supported by a postdoctoral research fellowship from the Million Dollar Bike Ride Grant Program of the Orphan Disease Center at University of Pennsylvania. T.T.H. was supported by the American College of Medical Genetics Foundation. A.C.P. and M.G.M. were supported by the SURE and OSCTR programs at OUHSC, respectively

    Avoiding Chaos in Wonderland

    Full text link
    Wonderland, a compact, integrated economic, demographic and environmental model is investigated using methods developed for studying critical phenomena. Simulation results show the parameter space separates into two phases, one of which contains the property of long term, sustainable development. By employing information contain in the phase diagram, an optimal strategy involving pollution taxes is developed as a means of moving a system initially in a unsustainable region of the phase diagram into a region of sustainability while ensuring minimal regret with respect to long term economic growth.Comment: 22 pages, 9 figures. Submitted to Physica
    • …
    corecore