37 research outputs found

    On Voice in Poetry: The Work of Animation by David Nowell Smith

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    A review of On Voice In Poetry: The Work of Animation, by David Nowell Smith

    Thermal resilience of microcracked andesitic dome rocks

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    International audienceThe strength of the rocks forming a lava dome informs on its structural stability, important for volcanic hazard assessments. Dome-forming rocks are persistently challenged by thermal stresses from recurring eruptive events that may reduce their strength and jeopardise the structural stability of the dome. Here, we present a series of experiments to better understand the impact of thermal stresses on the strength of an andesitic dome rock from VolcĆ”n de Colima (Mexico), a volcano that has witnessed some substantial dome collapses in recent years. Uniaxial compressive strength (UCS) was first tested at room temperature on as-collected samples and samples that had undergone either slow (heated and cooled at 1ā€ÆĀ°C/min) or shock (heated at 1ā€ÆĀ°C/min and shock-cooled in cold water) thermal stressing to target temperatures of 400ā€“700ā€ÆĀ°C. Slow- and shock-cooling thermal stressing did not measurably alter sample strength, connected porosity, or permeability. UCS tests performed at high in-situ temperatures (400ā€“700ā€ÆĀ°C), however, showed an increase in sample strength and stiffness. We interpret that the resistance of this rock to thermal stresses results from both the presence of abundant pre-existing microcracks and the thermal stability of its mineral assemblage. Unchanged physical properties for the thermally stressed samples deformed at room temperature suggests that the pre-existing microcracks close and reopen, respectively, as the rock expands and contracts during heating and cooling to accommodate the volumetric changes without further microcracking. The increase in strength and stiffness at high in-situ temperatures can be explained by the closure of microcracks due to thermal expansion. These observations suggest that the strength of microcracked dome rocks (1) may be slightly higher when hot (below the glass transition of the groundmass glass), although ā€œupscaledā€ strength estimates highlight that dome strength will be largely unchanged by an increase in temperature, (2) may only be reduced following the first thermal stressing event, and (3) may not be further reduced by repeated thermal stressing events. Therefore, thermal perturbations, often observed at active domes, may not, as perhaps expected, repeatedly degrade the strength of individual blocks forming the lava dome and therefore may not jeopardise dome stability

    The UK stand together trial: protocol for a multicentre cluster randomised controlled trial to evaluate the effectiveness and cost-effectiveness of KiVa to reduce bullying in primary schools

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    Background Reducing bullying is a public health priority. KiVa, a school-based anti-bullying programme, is effective in reducing bullying in Finland and requires rigorous testing in other countries, including the UK. This trial aims to test the effectiveness and cost-effectiveness of KiVa in reducing child reported bullying in UK schools compared to usual practice. The trial is currently on-going. Recruitment commenced in October 2019, however due to COVID-19 pandemic and resulting school closures was re-started in October 2020. Methods Design: Two-arm pragmatic multicentre cluster randomised controlled trial with an embedded process and cost-effectiveness evaluation. Participants: 116 primary schools from four areas; North Wales, West Midlands, South East and South West England. Outcomes will be assessed at student level (ages 7ā€“11ā€‰years; n = approximately 13,000 students). Intervention: KiVa is a whole school programme with universal actions that places a strong emphasis on changing bystander behaviour alongside indicated actions that provide consistent strategies for dealing with incidents of bullying. KiVa will be implemented over one academic year. Comparator: Usual practice. Primary outcome: Student-level bullying-victimisation assessed through self-report using the extensively used and validated Olweus Bully/Victim questionnaire at baseline and 12-month follow-up. Secondary outcomes: student-level bullying-perpetration; student mental health and emotional well-being; student level of, and roles in, bullying; school related well-being; school attendance and academic attainment; and teachersā€™ self-efficacy in dealing with bullying, mental well-being, and burnout. Sample size: 116 schools (58 per arm) with an assumed ICC of 0.02 will provide 90% power to identify a relative reduction of 22% with a 5% significance level. Randomisation: recruited schools will be randomised on 1:1 basis stratified by Key-Stage 2 size and free school meal status. Process evaluation: assess implementation fidelity, identify influences on KiVa implementation, and examine intervention mechanisms. Economic evaluation: Self-reported victimisation, Child Health Utility 9D, Client Service Receipt Inventory, frequency of services used, and intervention costs. The health economic analysis will be conducted from a schools and societal perspective. Discussion This two-arm pragmatic multicentre cluster randomised controlled trial will evaluate the KiVa anti-bullying intervention to generate evidence of the effectiveness, cost-effectiveness and scalability of the programme in the UK. Our integrated process evaluation will assess implementation fidelity, identify influences on KiVa implementation across England and Wales and examine intervention mechanisms. The integrated health economic analysis will be conducted from a schools and societal perspective. Our trial will also provide evidence regarding the programme impact on inequalities by testing whether KiVa is effective across the socio-economic gradient

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