699 research outputs found

    Multi-objective Optimizations of a Novel Cryo-cooled DC Gun Based Ultra Fast Electron Diffraction Beamline

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    We present the results of multi-objective genetic algorithm optimizations of a potential single shot ultra fast electron diffraction beamline utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at sample location have been performed for three different sample radii: 50, 100, 200 microns, for two final bunch charges: 100k and 1000k electrons. Analysis of the solutions is discussed, as are the effects of disorder induced heating. In particular, a coherence length per rms spot size of 0.27 nm/micron was obtained for a final bunch charge of 100k electrons and final rms bunch length of approximately 100 fs. For a final charge of 1000k electrons the cryogun produces a coherence length per rms spot size of 0.1 nm/micron for an rms bunch length of 100-200 fs and final spot size of 50 micron. These results demonstrate the viability of using genetic algorithms in the design and operation of ultrafast electron diffraction beamlines

    Academic and social and emotional interventions in response to COVID-19 school closures

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    Since 23rd March 2020, UK schools have been closed for most children, due to the COVID-19 pandemic. Schools are unlikely to re-open to the majority of pupils before September, meaning some will be out of school for more than six months. As school relationships serve as a buffer against psycho-social risks and against the risk of low academic attainment, particularly for children of low-income families (Masten and Barnes, 2018), the vulnerabilities of many children may have significantly increased as a consequence of the school closures. Research suggests that long absences from school are likely to have a negative effect on academic achievement and increase achievement gaps (see Sims, 2020). Inequalities in resources and time available to families to spend on home schooling is likely to exacerbate existing achievement gaps (see Dickson & Macmillan, 2020; Outhwaite, 2020). There may also be significant challenges to mental health and wellbeing in schools after lockdown (Lee, 2020). Children and young people have been away from the community and structure that school provides. Some may carry personal losses, and some may have experienced significant stressors in the family. Mental health and wellbeing are fundamental to learning and development (Panayiotou et al., 2019), and therefore must be prioritised in the post-lockdown transition and beyond. This briefing note summarises the empirical evidence on approaches to closing achievement gaps and supporting the most vulnerable children in academic, and social and emotional learning as schools can safely re-open

    A new methodological approach for evaluating the impact of educational intervention implementation on learning outcomes

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    Randomized control trials (RCTs) are commonly regarded as the ‘gold standard’ for evaluating educational interventions. While this experimental design is valuable in establishing causal relationships between the tested intervention and outcomes, reliance on statistical aggregation typically underplays the situated context in which interventions are implemented. Developing innovative, systematic methods for evaluating implementation and understanding its impact on outcomes is vital to moving educational evaluation research beyond questions of ‘what works’, towards better understanding the mechanisms underpinning an intervention’s effects. The current study presents a pragmatic, two-phased approach that combines qualitative data with quantitative analyses to examine the causal relationships between intervention implementation and outcomes. This new methodological approach is illustrated in the context of a maths app intervention recently evaluated in a RCT across 11 schools. In phase I, four implementation themes were identified; ‘teacher support’, ‘teacher supervision’, ‘implementation quality’, and ‘established routine’. In phase II, ‘established routine’ was found to predict 41% of the variance in children’s learning outcomes with the apps. This has significant implications for future scaling. Overall, this new methodological approach offers an innovative method for combining process and impact evaluations when seeking to gain a more nuanced understanding of what works in education and why

    Raising early achievement in math with interactive apps: a randomized control trial

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    Improving provision and raising achievement in early math for young children is of national importance. Child-centered apps offer an opportunity to develop strong foundations in learning math as they deliver one-to-one instruction. Reported here is the first pupil-level randomized control trial in the United Kingdom of interactive math apps designed for early years education, with 389 children aged 4–5 years. The original and rigorous research design disentangled the impact of the math apps as a form of quality math instruction from additional exposure to math. It was predicted that using the apps would increase math achievement when implemented by teachers in addition to standard math activities (treatment) or instead of a regular small group-based math activity (time-equivalent treatment) compared with standard math practice only (control). After a 12-week intervention period, results showed significantly greater math learning gains for both forms of app implementation compared with standard math practice. The math apps supported targeted basic facts and concepts and generalized to higher-level math reasoning and problem solving skills. There were no significant differences between the 2 forms of math app implementation, suggesting the math apps can be implemented in a well-balanced curriculum. Features of the interactive apps, which are grounded in instructional psychology and combine aspects of direct instruction with play, may account for the observed learning gains. These novel results suggest that structured, content-rich, interactive apps can provide a vehicle for efficiently delivering high-quality math instruction for all pupils in a classroom context and can effectively raise achievement in early math

    An MLE method for finding LKB NTCP model parameters using Monte Carlo uncertainty estimates

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    The aims of this work were to establish a program to fit NTCP models to clinical data with multiple toxicity endpoints, to test the method using a realistic test dataset, to compare three methods for estimating confidence intervals for the fitted parameters and to characterise the speed and performance of the program

    Multiple morbidity across the lifespan in people with Down syndrome or intellectual disabilities: a population-based cohort study using electronic health records.

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    BACKGROUND: The Down syndrome phenotype is well established, but our understanding of its morbidity patterns is limited. We comprehensively estimated the risk of multiple morbidity across the lifespan in people with Down syndrome compared with the general population and controls with other forms of intellectual disability. METHODS: In this matched population-based cohort-study design, we used electronic health-record data from the UK Clinical Practice Research Datalink (CRPD) from Jan 1, 1990, to June 29, 2020. We aimed to explore the pattern of morbidities throughout the lifespan of people with Down syndrome compared with people with other intellectual disabilities and the general population, to identify syndrome-specific health conditions and their age-related incidence. We estimated incidence rates per 1000 person-years and incidence rate ratios (IRRs) for 32 common morbidities. Hierarchical clustering was used to identify groups of associated conditions using prevalence data. FINDINGS: Between Jan 1, 1990, and June 29, 2020, a total of 10 204 people with Down syndrome, 39 814 controls, and 69 150 people with intellectual disabilities were included. Compared with controls, people with Down syndrome had increased risk of dementia (IRR 94·7, 95% CI 69·9-128·4), hypothyroidism (IRR 10·6, 9·6-11·8), epilepsy (IRR 9·7, 8·5-10·9), and haematological malignancy (IRR 4·7, 3·4-6·3), whereas asthma (IRR 0·88, 0·79-0·98), cancer (solid tumour IRR 0·75, 0·62-0·89), ischaemic heart disease (IRR 0·65, 0·51-0·85), and particularly hypertension (IRR 0·26, 0·22-0·32) were less frequent in people with Down syndrome than in controls. Compared to people with intellectual disabilities, risk of dementia (IRR 16·60, 14·23-19·37), hypothyroidism (IRR 7·22, 6·62-7·88), obstructive sleep apnoea (IRR 4·45, 3·72-5·31), and haematological malignancy (IRR 3·44, 2·58-4·59) were higher in people with Down syndrome, with reduced rates for a third of conditions, including new onset of dental inflammation (IRR 0·88, 0·78-0·99), asthma (IRR 0·82, 0·73-0·91), cancer (solid tumour IRR 0·78, 0·65-0·93), sleep disorder (IRR 0·74, 0·68-0·80), hypercholesterolaemia (IRR 0·69, 0·60-0·80), diabetes (IRR 0·59, 0·52-0·66), mood disorder (IRR 0·55, 0·50-0·60), glaucoma (IRR 0·47, 0·29-0·78), and anxiety disorder (IRR 0·43, 0·38-0·48). Morbidities in Down syndrome could be categorised on age-related incidence trajectories, and their prevalence clustered into typical syndromic conditions, cardiovascular diseases, autoimmune disorders, and mental health conditions. INTERPRETATION: Multiple morbidity in Down syndrome shows distinct patterns of age-related incidence trajectories and clustering that differ from those found in the general population and in people with other intellectual disabilities, with implications for provision and timing of health-care screening, prevention, and treatment for people with Down syndrome. FUNDING: The European Union's Horizon 2020 Research and Innovation Programme, the Jérôme Lejeune Foundation, the Alzheimer's Society, the Medical Research Council, the Academy of Medical Sciences, the Wellcome Trust, and William Harvey Research Limited
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