254 research outputs found

    Unsteady stagnation-point heat transfer during passage of a concentrated vortex

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    The unsteady boundary layer due to a single rectilinear vortex filament approaching a 2-D stagnation point is investigated. Assuming the vortex remains far from the surface, incompressible potential flow theory is used to determine the time dependent inviscid flow field. The unsteady boundary layer equations are solved by an alternating-direction-implicit finite-difference method. Two mechanisms which cause fluctuations in heat transfer are the unsteady velocity field in the boundary layer and secondly, the unsteady total temperature at the edge of the boundary layer. The relative importance of these mechanisms is dependent upon the total temperature fluctuations relative to the imposed temperature difference. As a vortex approaches a stagnation point it may be forced to one side of the stagnation line or the other, depending on its initial position. Results are presented for both of these cases

    China's pragmatic security policy: The middle-power factor

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    Guilt, shame and expressed emotion in carers of people with long-term mental health difficulties:a systematic review

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    Expressed emotion (EE) is a global index of familial emotional climate, whose primary components are emotional over-involvement (EOI) and critical comments (CC)/hostility. There is a strong theoretical rationale for hypothesising that carers’ guilt and shame may be differentially associated with their EOI and CC/hostility respectively. This systematic review investigates the magnitude of these theorised associations in carers of people with long-term mental health difficulties. Electronic searches (conducted in May 2016 across Medline, CINAHL, Embase, PsycINFO and ProQuest) were supplemented with iterative hand searches. Ten papers, reporting data from eight studies, were included. Risk of bias was assessed using a standardised checklist. Relevant data were extracted and synthesised narratively. EOI was positively associated with both guilt and shame, whereas CC/hostility was positively associated with shame. The strength of associations varied depending on whether or not guilt and shame were assessed within the context of the caring relationship. Based on these data, an argument can be made for the refinement, development and evaluation of systemic and individual interventions designed to target carers’ guilt and shame. However, more research is needed to clarify the strength of these associations and their direction of effect before firm conclusions can be drawn

    Pseudotumor cerebri syndrome in childhood : incidence, clinical profile and risk factors in a national prospective population-based cohort study

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    Aim To investigate the epidemiology, clinical profile and risk factors of pseudotumor cerebri syndrome (PTCS) in children aged 1-16 years. Methods A national prospective population-based cohort study over 25 months. Newly diagnosed PTCS cases notified via British Paediatric Surveillance Unit (BPSU) were ascertained using classical diagnostic criteria and categorised according to 2013 revised diagnostic criteria. We derived national age, sex and weight-specific annual incidence rates and assessed effects of sex and weight category. Results We identified 185 PTCS cases of which 166 also fulfilled revised diagnostic criteria. The national annual incidence (95% CI) of childhood PTCS aged 1-16 years was 0.71 (0.57- 0.87) per 100,000 population increasing with age and weight to 4.18 and 10.7 per 100,000 in obese 12-15 year old boys and girls respectively. Incidence rates under 7 years were similar in both sexes. From 7 years onwards, the incidence in girls was double that in boys, but only in overweight (including obese) children. In 12-15 year old children, an estimated 82% of the incidence of PTCS was attributable to obesity. Two subgroups of PTCS were apparent: 168 (91%) cases aged from 7 years frequently presented on medication and with headache, and were predominantly female and obese. The remaining 17 (9%) cases under 7 years often lacked these risk factors and commonly presented with new onset squint. Conclusions This uniquely largest population-based study of childhood PTCS will inform the design of future intervention studies. It suggests that weight reduction is central to the prevention of PTCS

    Safety of Infusing Rituximab at a More Rapid Rate in Patients with Rheumatoid Arthritis: Results from the RATE-RA Study

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    As recommended in the current prescribing information, rituximab infusions in patients with rheumatoid arthritis (RA) take 4.25hours for the first infusion and 3.25hours for subsequent infusions, which is a burden on patients and the health care system. We therefore evaluated the safety of infusing rituximab at a faster rate for an infusion period of 2hours in patients with RA

    Sustained inhibition of progressive joint damage with rituximab plus methotrexate in early active rheumatoid arthritis: 2-year results from the randomised controlled trial IMAGE

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    Background In the IMAGE study, rituximab plus methotrexate (MTX) inhibited joint damage and improved clinical outcomes at 1 year in MTX-naive patients with early active rheumatoid arthritis. Objective The aim of this study was to assess joint damage progression and clinical outcomes over 2 years. Methods Patients (n=755) were randomised to receive rituximab 2x500 mg+MTX, 2x1000 mg+MTX or placebo+MTX. The placebo-controlled period continued to week 104. Two-year end points were defined as secondary or exploratory and included change in total Genant-modified Sharp score (mTSS), total erosion score and joint space narrowing score from baseline to week 104. Clinical efficacy and physical function end points were also assessed. Results At 2 years, rituximab 2x1000 mg+MTX maintained inhibition of progressive joint damage versus MTX alone (mTSS change 0.41 vs 1.95; p <0.0001 (79% inhibition)), and a higher proportion of patients receiving rituximab 2x1000 mg+MTX had no radiographic progression over 2 years compared with those receiving MTX alone (57% vs 37%; p <0.0001). Contrary to 1-year results, exploratory analysis of rituximab 2x500 mg+MTX at 2 years showed that progressive joint damage was slowed by similar to 61% versus placebo+MTX (mTSS, exploratory p=0.0041). Improvements in clinical signs and symptoms and physical function seen after 1 year in rituximab-treated patients versus those receiving placebo were maintained at year 2. Safety profiles were similar between groups. Conclusions Treatment with rituximab 2x1000 mg+MTX was associated with sustained improvements in radiographic, clinical and functional outcomes over 2 year

    Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF3CH2Cl)

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    Hydrochlorofluorocarbon HCFC-133a (CF3CH2Cl) is an anthropogenic compound whose consumption for emissive use is restricted under the Montreal Protocol. A recent study showed rapidly increasing atmospheric abundances and emissions. We report that, following this rise, the at- mospheric abundance and emissions have declined sharply in the past three years. We find a Northern Hemisphere HCFC-133a increase from 0.13 ppt (dry air mole fraction in parts-per-trillion) in 2000 to 0.50 ppt in 2012–mid-2013 followed by an abrupt reversal to 0.44 ppt by early 2015. Global emissions derived from these observations peaked at 3.1 kt in 2011, followed by a rapid decline of 0.5 kt yr−2 to 1.5 kt yr−1 in 2014. Sporadic HCFC-133a pollution events are detected in Europe from our high-resolution HCFC-133a records at three European stations, and in Asia from sam- ples collected in Taiwan. European emissions are estimated to be <0.1 kt yr−1 although emission hotspots were identi- fied in France

    NuSTAR Spectroscopy of Multi-Component X-ray Reflection from NGC 1068

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    We report on observations of NGC1068 with NuSTAR, which provide the best constraints to date on its >10>10~keV spectral shape. We find no strong variability over the past two decades, consistent with its Compton-thick AGN classification. The combined NuSTAR, Chandra, XMM-Newton, and Swift-BAT spectral dataset offers new insights into the complex reflected emission. The critical combination of the high signal-to-noise NuSTAR data and a spatial decomposition with Chandra allow us to break several model degeneracies and greatly aid physical interpretation. When modeled as a monolithic (i.e., a single N_H) reflector, none of the common Compton-reflection models are able to match the neutral fluorescence lines and broad spectral shape of the Compton reflection. A multi-component reflector with three distinct column densities (e.g., N_H~1.5e23, 5e24, and 1e25 cm^{-2}) provides a more reasonable fit to the spectral lines and Compton hump, with near-solar Fe abundances. In this model, the higher N_H components provide the bulk of the Compton hump flux while the lower N_H component produces much of the line emission, effectively decoupling two key features of Compton reflection. We note that ~30% of the neutral Fe Kalpha line flux arises from >2" (~140 pc), implying that a significant fraction of the <10 keV reflected component arises from regions well outside of a parsec-scale torus. These results likely have ramifications for the interpretation of poorer signal-to-noise observations and/or more distant objects [Abridged].Comment: Submitted to ApJ; 23 pages (ApJ format); 11 figures and 3 tables; Comments welcomed
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