922017 research outputs found
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Social support resilience as a protective mental health factor in postgraduate researchers’ experiences: a longitudinal analysis.
No full textPurpose: The aims of this research were to examine across a six-month period in post-graduate research (PGR) students i. mental health and well-being, ii. the effect of academic pressures on depression, anxiety and well-being, and iii. the extent to which psychological resilience buffered against academic pressures.Design/methodology/approach: This was a longitudinal questionnaire study with predictor variables of six types of academic pressure, outcome variables of depression, anxiety and well-being, and a moderator of resilience.Findings: Well-being significantly worsened across the six month timeframe, but levels of depression and anxiety remained relatively stable. Negative perceptions of academic challenges at baseline significantly predicted anxiety, but not depression or well-being, six months later. Negative appraisals of relationships with supervisors, other university staff, and work peers were not predictors of anxiety. Social support resilience which was present at baseline buffered the relationship between perceived academic challenges and anxiety.Originality: This is the first study to examine the effects of negative perceptions of multiple facets of academic life on depression, anxiety and well-being longitudinally. Additionally, it is the first study to investigate, and demonstrate, the extent to which psychological resilience can lessen the relationship between academic challenges and anxiety over time.Implications: Higher Education Institutions have a duty of care towards PGR students many of whom struggle with escalating interactions between mental health problems and academic pressures. Actively nurturing psychological resilience related to social support is key at the level of the individual students and the PGR community but more broadly at an institutional level. KEYWORDS: post-graduate; doctoral; longitudinal; academic pressures; mental health; depression; anxiety; well-being; psychological resilience; social support<br/
A Perspective on Welding Technology Challenges in the Nuclear Sector
No full textThis article describes three areas that, in the opinion of the author, should be priorities for development in the nuclear sector. The application of electron-beam (or laser in vacuo) welding to pressure vessel fabrication; the optimisation of filler metal compositions for multipass steel welds; and the pre-fabrication of dissimilar metal transition pieces are each highlighted and discussed. While conceived with the nuclear sector in mind, these priority areas are relevant more generally to the welding of pressure vessels, piping and similar structures. The intention is to stimulate ideas, to provoke debate, and to encourage the welding community to rise to the challenges that must be overcome as we transition to a low-carbon future
Investigating Characteristics of Idiopathic Inflammatory Myopathy Flares Using Daily Symptom Data Collected Via a Smartphone App
No full textObjectivesTo use daily data collected via a smartphone app for characterisation of patient-reported and “symptom-based” (using an a priori definition) flares in an adult idiopathic inflammatory myopathy (IIM) cohort.MethodsUK adults with an IIM answered patient-reported outcome measurements (PROMs) daily via a smartphone app during a 91 day study. Daily symptom PROMs addressed global activity, overall pain, myalgia, fatigue, and weakness (0-100 visual analogue scale). Patient-reported flares were recorded via a weekly app question. “Symptom-based” flares were defined via an a priori definition based on increase of daily symptom data from the previous four day mean.ResultsTwenty participants (65% female) participated. Patient-reported flares occurred on a median of five weeks (IQR 3, 7) per participant, out of a possible 13. The mean of each symptom score was significantly higher in flare weeks, compared to non-flare weeks (e.g. mean flare week myalgia score 34/100, vs 21/100 during non-flare week, t-test p-value <0.01).Fatigue accounted for the most symptom-based flares (incidence-rate 23/100 person-days [95% CI 19, 27]), and myalgia the fewest (incidence rate 13/100 person-days [95% CI 11, 16]). Symptom-based flares typically resolved after three days, although fatigue-predominant flares lasted two days. The majority (69%) of patient-reported flare weeks coincided with at least one symptom-based flare.ConclusionsIIM flares are frequent and associated with increased symptom scores. This study has demonstrated the ability to identify and characterise patient-reported and symptom-based flares (based on an a priori definition), using daily app-collected data
Impact of occupational pesticide exposure assessment method on rist estimates for prostate cancer, non-Hodgkin's lymphoma and Parkinson's disease - results of three meta-analyses
No full textObjective: Assessment of occupational pesticide exposure in epidemiological studies of chronic diseases is challenging. Biomonitoring of current pesticide levels might not correlate with past exposure relevant to disease etiology, and indirect methods often rely on workers’ imperfect recall of exposures, or job titles. We investigated how applied exposure assessment method (EAM) influenced risk estimates for some chronic diseases. Methods: In three meta-analyses the influence of EAM type on the summary risk ratio (sRR) of prostate cancer (25 articles), Non-Hodgkin’s lymphoma (NHL) (30 articles), and Parkinson’s disease (PD) (32 articles) was investigated. EAM types analysed were: group-level assessments (e.g. job titles), self-reported exposures, expert-level assessments (e.g. job-exposure matrices), and biomonitoring (e.g. blood, urine). Additionally, sRRs were estimated by study design, publication year period, and geographic location where the study was conducted.Results: EAM types were not associated with statistically significant different sRRs across any of the health outcomes. Heterogeneity in results varied from high in cancer studies to moderate and low in PD studies. Overall, case-control designs showed significantly higher sRR estimates than prospective cohort designs. Later NHL publications showed significantly higher sRR estimates than earlier. For prostate cancer, studies from North America showed significantly higher sRR estimates than studies from Europe. Conclusion: Exposure assessment method applied in studies of occupational pesticides appears not to have a significant effect on risk estimates for prostate cancer, NHL, and PD. In systematic reviews of chronic health effects of occupational exposure to pesticides, epidemiological study design, publication year, and geographic location, should primarily be considered. <br/
Initial Conditions for Star Formation: A Physical Description of the Filamentary ISM
No full textThe interstellar medium contains filamentary structure over a wide range of scales. Understanding the role of this structure, both as a conduit of gas across the scales and a diagnostic tool of local physics, is a major focus of star formation studies. We review recent progress in studying filamentary structure in the ISM, interpreting its properties in terms of physical processes, andexploring formation and evolution scenarios. We include structures from galactic-scale filaments to tenth-of-a-parsec scale filaments, comprising both molecular and atomic structures, from both observational and theoretical perspectives. In addition to the literature overview, we assemble a large amount of catalogue data from different surveys and provide the most comprehensive census of filamentary structures to date. Our census consists of 22 803 filamentary structures, facilitating a holistic perspective and new insights. We use our census to conduct a meta-analysis, leading to a description of filament properties over four orders of magnitudes in length and eight in mass. Our analysis emphasises the hierarchical and dynamical nature of filamentary structures. Filaments do not live in isolation, nor they generally resemble static structures close to equilibrium. We propose that accretion during filament formation and evolution sets some of the key scaling properties of filaments. This highlights the role of accretion during filament formation and evolution and also in setting the initial conditions for star formation. Overall, the study of filamentary structures during the past decade has been observationally driven. While great progress has been made on measuring the basic properties of filaments, our understanding of their formation and evolution is clearly lacking. In this context, we identify a number of directions and questions we consider most pressing for the field
Recovering the second moment of the strain distribution from neutron Bragg edge data
No full textPoint by point strain scanning is often used to map the residual stress (strain) in engineering materials and components. However, the gauge volume and hence spatial resolution is limited by the beam defining apertures and can be anisotropic for very low and high diffraction (scattering) angles. Alternatively, wavelength resolved neutron transmission imaging has a potential to retrieve information tomographically about residual strain induced within materials through measurement in transmission of Bragg edges – crystallographic fingerprints whose locations and shapes depend on microstructure and strain distribution. In such a case the spatial resolution is determined by the geometrical blurring of the measurement setup and the detector point spread function. Mathematically, reconstruction of strain tensor field is described by the longitudinal ray transform; this transform has a non-trivial null-space, making direct inversion impossible. A combination of the longitudinal ray transform with physical constraints was used to reconstruct strain tensor fields in convex objects. To relax physical constraints and generalise reconstruction, a recently introduced concept of histogram tomography can be employed. Histogram tomography relies on our ability to resolve the distribution of strain in the beam direction, as we discuss in the paper. More specifically, Bragg edge strain tomography requires extraction of the second moment (variance about zero) of the strain distribution which has not yet been demonstrated in practice. In this paper we verify experimentally that the second moment can be reliably measured for a previously well characterised aluminium ring and plug sample. We compare experimental measurements against numerical calculation and further support our conclusions by rigorous uncertainty quantification of the estimated mean and variance of the strain distribution
Biographical accounts of the impact of fatigue in young people with sickle cell disease
No full textChildren and young people (CYP) with sickle cell disease (SCD) are a 'missing voice' in the debate on biography and sociology of chronic illness, meaning we know little about the social consequences of the illness for CYP. This paper examines the meaning of fatigue (a common symptom) for adolescents with SCD. Analysing 24 in-depth interviews with adolescents aged 12-17 years in Ghana, we draw on the distinction proposed by Bury (1988) between 'meanings as significance' and 'meanings as consequence' to examine biographical aspects of fatigue. We argue that concepts of 'biographical disruption' and 'normal illness' do not easily accommodate the experience of CYP with congenital chronic illnesses like SCD, as their sense of (un)disruption and normality/continuity is contextualised relative to normative expectations about what it is to be a young person. At biographical transition points, illness/symptoms present from birth may evolve, shift and become experienced as 'new', 'different', or 'non-normal'. They may become restrictive rather than continuous or disruptive. These experiences are influenced primarily by normative biographical expectations and the pursuit of identity affirmations. We propose that biographical restriction, biographical enactment, biographical abandonment and biographical reframing are more relevant concepts for understanding the experiences of CYP living with SCD
A discontinuous model of duopoly with isoelastic demand and innovation costs
No full textThe paper studies the dynamic properties of a duopoly game in which firms strategically compete in quality-enhancing innovation investments and quantities. Market demands are assumed to be isolastic (reciprocal to the price) functions. The non-linearity of the demand functions, as already highlighted by T. Puu in [11], suggests the existence of complicated dynamics (cyclical or chaotic) in a standard dynamic Cournot duopoly. In addition to this, competition in innovation introduces the presence of discontinuities in the best response functions, expanding the set of possible equilibria (including asymmetric and multiple ones) of the standard Cournot duopoly and further enriching the dynamic features of the model.<br/
Social support resilience as a protective mental health factor in postgraduate researchers’ experiences: a longitudinal analysis.
No full textPurpose: The aims of this research were to examine across a six-month period in post-graduate research (PGR) students i. mental health and well-being, ii. the effect of academic pressures on depression, anxiety and well-being, and iii. the extent to which psychological resilience buffered against academic pressures.Design/methodology/approach: This was a longitudinal questionnaire study with predictor variables of six types of academic pressure, outcome variables of depression, anxiety and well-being, and a moderator of resilience.Findings: Well-being significantly worsened across the six month timeframe, but levels of depression and anxiety remained relatively stable. Negative perceptions of academic challenges at baseline significantly predicted anxiety, but not depression or well-being, six months later. Negative appraisals of relationships with supervisors, other university staff, and work peers were not predictors of anxiety. Social support resilience which was present at baseline buffered the relationship between perceived academic challenges and anxiety.Originality: This is the first study to examine the effects of negative perceptions of multiple facets of academic life on depression, anxiety and well-being longitudinally. Additionally, it is the first study to investigate, and demonstrate, the extent to which psychological resilience can lessen the relationship between academic challenges and anxiety over time.Implications: Higher Education Institutions have a duty of care towards PGR students many of whom struggle with escalating interactions between mental health problems and academic pressures. Actively nurturing psychological resilience related to social support is key at the level of the individual students and the PGR community but more broadly at an institutional level. KEYWORDS: post-graduate; doctoral; longitudinal; academic pressures; mental health; depression; anxiety; well-being; psychological resilience; social support<br/
Advancing OHL Rating Calculations: Modeling Mixed-Convective Cooling and Conductor Geometry
No full textThe existing standard current-temperature calculations for overhead line (OHL) conductors have been adequate for conventional conductors and their operating temperatures. However, these calculations make assumptions and include simplifications about conductor geometry and aero-thermal-dynamics, introducing an error in the High-Temperature Low-Sag conductors operating temperatures. To quantify the error introduced by the shape of strands, the paper employs a Multi-Physics Finite Element Modeling approach that calculates the conjugate heat transfer for trapezoidal stranded OHL conductors. Furthermore, it proposes corrective equations to improve the accuracy of existing methods. The equations incorporate a new Nusselt number correlation for mixed convection and capture the surface area ignored by current calculations. The outer conductor geometry assumptions and the combined natural and forced convective cooling omission in the IEEE and CIGRE methods introduce an error at low (below 0.12 m/s) cross-flow wind speeds suggesting an underestimation of conductor temperature by up to 4%. In medium wind speeds, typically at 0.5 m/s - 0.61 m/s, the standard methods overestimate the conductor temperature limiting its current-carrying capability. A 5% uprating for existing OHLs is potentially feasible, particularly for the trapezoidal stranded conductors, when removing the assumptions made in existing methods