43,295 research outputs found

    Prevalence of Chronic airflow limitation in Kashmir, North India: Results from the BOLD study.

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    BACKGROUND: Data on spirometrically defined chronic airflow limitation (CAL) are scarce in developing countries. OBJECTIVE: To estimate the prevalence of spirometrically defined CAL in Kashmir, North India. METHODS: Using Burden of Obstructive Lung Disease survey methods, we administered questionnaires to randomly selected adults aged 40 years. Post-bronchodilator spirometry was performed to estimate the prevalence of CAL and its relation to potential risk factors. RESULTS: Of 1100 participants initially recruited, 953 (86.9%) responded and 757 completed acceptable spirometry and questionnaires. The prevalence of a forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio less than the lower limit of normal was 17.3% (4.5) in males and 14.8% (2.1) in females. Risk factors for CAL included higher age, cooking with wood and lower educational status. The prevalence of current smoking was 61% in males and 22% in females; most smoked hookahs. CAL was found equally in non-smoking males and females, and was independently associated with the use of the hookah, family history of respiratory disease and poor education. A self-reported doctor's diagnosis of chronic obstructive pulmonary disease was reported in 8.4/1000 (0.9% of females and 0.8% of males). CONCLUSION: Spirometrically confirmed CAL is highly prevalent in Indian Kashmir, and seems to be related to the high prevalence of smoking, predominantly in the form of hookah smoking

    Diagnosing numerical Cherenkov instabilities in relativistic plasma simulations based on general meshes

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    Numerical Cherenkov radiation (NCR) or instability is a detrimental effect frequently found in electromagnetic particle-in-cell (EM-PIC) simulations involving relativistic plasma beams. NCR is caused by spurious coupling between electromagnetic-field modes and multiple beam resonances. This coupling may result from the slow down of poorly-resolved waves due to numerical (grid) dispersion and from aliasing mechanisms. NCR has been studied in the past for finite-difference-based EM-PIC algorithms on regular (structured) meshes with rectangular elements. In this work, we extend the analysis of NCR to finite-element-based EM-PIC algorithms implemented on unstructured meshes. The influence of different mesh element shapes and mesh layouts on NCR is studied. Analytic predictions are compared against results from finite-element-based EM-PIC simulations of relativistic plasma beams on various mesh types.Comment: 31 pages, 20 figure

    Wackiness and event management: the case of the World Alternative Games

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    The World Alternative Games (WAG) is a biennial event which takes place in Britain’s smallest town. This paper considers the ways in which wackiness is central to event spaces within the town of Llanwrtyd Wells, Wales. Based on a social constructivist approach, this work sheds light on aspects of the concept development, planning and organisation of events within a particular locale. It shows how wackiness is an important element of the event management development in the town and a key part of wider rural tourism development

    Numerical and physical simulation of rapid microstructural evolution of gas atomised Ni superalloy powders

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    The rapid microstructural evolution of gas atomised Ni superalloy powder compacts over timescales of a few seconds was studied using a Gleeble 3500 thermomechanical simulator, finite element based numerical model and electron microscopy. The study found that the microstructural changes were governed by the characteristic temperatures of the alloy. At a temperature below the γ' solvus, the powders maintained dendritic structures. Above the γ' solvus temperature but in the solid-state, rapid grain spheroidisation and coarsening occurred, although the fine-scale microstructures were largely retained. Once the incipient melting temperature of the alloy was exceeded, microstructural change was rapid, and when the temperature was increased into the solid + liquid state, the powder compact partially melted and then re-solidified with no trace of the original structures, despite the fast timescales. The study reveals the relationship between short, severe thermal excursions and microstructural evolution in powder processed components, and gives guidance on the upper limit of temperature and time for powder-based processes if desirable fine-scale features of powders are to be preserved

    The diameter of the world wide web

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    Despite its increasing role in communication, the world wide web remains the least controlled medium: any individual or institution can create websites with unrestricted number of documents and links. While great efforts are made to map and characterize the Internet's infrastructure, little is known about the topology of the web. Here we take a first step to fill this gap: we use local connectivity measurements to construct a topological model of the world wide web, allowing us to explore and characterize its large scale properties.Comment: 5 pages, 1 figure, updated with most recent results on the size of the ww

    Structure of the neutron-rich N=7 isotones 10Li and 9He

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    The near threshold structure of the unbound N=7 isotones 10Li and 9He has been investigated using proton removal and breakup from intermediate energy (35 MeV/nucleon) secondary beams of 11Be and 14,15B. The coincident detection of the beam velocity 9Li and 8He fragments and neutrons permitted the relative energy of the in-flight decay of 10Li and 9He to be reconstructed. Both systems were found to exhibited virtual s-wave strength near threshold together with a higher-lying resonance.Comment: 4 pages, 2 figures, Contribution to INPC2010 - "International Nuclear Physics Conference", Vancouver, Canada, 4-9 July 2010, Proceedings to be published in Journal of Physics: Conference Serie

    Quantifying the origin of metallic glass formation

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    The waiting time to form a crystal in a unit volume of homogeneous undercooled liquid exhibits a pronounced minimum τ_X* at a ‘nose temperature’ T* located between the glass transition temperature T_g, and the crystal melting temperature, T_L. Turnbull argued that τ_X* should increase rapidly with the dimensionless ratio t_(rg)=T_g/T_L. Angell introduced a dimensionless ‘fragility parameter’, m, to characterize the fall of atomic mobility with temperature above T_g. Both t_(rg) and m are widely thought to play a significant role in determining τ_X*. Here we survey and assess reported data for T_L, T_g, t_(rg), m and τ_X* for a broad range of metallic glasses with widely varying τ_X*. By analysing this database, we derive a simple empirical expression for τ_X*(t_(rg), m) that depends exponentially on t_(rg) and m, and two fitting parameters. A statistical analysis shows that knowledge of t_(rg) and m alone is therefore sufficient to predict τ_X* within estimated experimental errors. Surprisingly, the liquid/crystal interfacial free energy does not appear in this expression for τ_X*

    Sound-Induced Flash Illusion is Resistant to Feedback Training

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    A single flash accompanied by two auditory beeps tends to be perceived as two flashes (Shams et al. Nature 408:788, 2000, Cogn Brain Res 14:147–152, 2002). This phenomenon is known as ‘sound-induced flash illusion.’ Previous neuroimaging studies have shown that this illusion is correlated with modulation of activity in early visual cortical areas (Arden et al. Vision Res 43(23):2469–2478, 2003; Bhattacharya et al. NeuroReport 13:1727–1730, 2002; Shams et al. NeuroReport 12(17):3849–3852, 2001, Neurosci Lett 378(2):76–81, 2005; Watkins et al. Neuroimage 31:1247–1256, 2006, Neuroimage 37:572–578, 2007; Mishra et al. J Neurosci 27(15):4120–4131, 2007). We examined how robust the illusion is by testing whether the frequency of the illusion can be reduced by providing feedback. We found that the sound-induced flash illusion was resistant to feedback training, except when the amount of monetary reward was made dependent on accuracy in performance. However, even in the latter case the participants reported that they still perceived illusory two flashes even though they correctly reported single flash. Moreover, the feedback training effect seemed to disappear once the participants were no longer provided with feedback suggesting a short-lived refinement of discrimination between illusory and physical double flashes rather than vanishing of the illusory percept. These findings indicate that the effect of sound on the perceptual representation of visual stimuli is strong and robust to feedback training, and provide further evidence against decision factors accounting for the sound-induced flash illusion

    Probiotic administration in congenital heart disease: a pilot study.

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    ObjectiveTo investigate the impact of probiotic Bifidobacterium longum ssp. infantis on the fecal microbiota and plasma cytokines in neonates with congenital heart disease.Study designSixteen infants with congenital heart disease were randomly assigned to receive either B. infantis (4.2 × 10(9) colony-forming units two times daily) or placebo for 8 weeks. Stool specimens from enrolled infants and from six term infants without heart disease were analyzed for microbial composition. Plasma cytokines were analyzed weekly in the infants with heart disease.ResultsHealthy control infants had increased total bacteria, total Bacteroidetes and total bifidobacteria compared to the infants with heart disease, but there were no significant differences between the placebo and probiotic groups. Plasma interleukin (IL)10, interferon (IFN)γ and IL1β levels were transiently higher in the probiotic group.ConclusionCongenital heart disease in infants is associated with dysbiosis. Probiotic B. infantis did not significantly alter the fecal microbiota. Alterations in plasma cytokines were found to be inconsistent
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