3,388 research outputs found

    Neural spike train synchronization indices: Definitions, interpretations, and applications

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    A comparison of previously defined spike train synchronization indices is undertaken within a stochastic point process framework. The second-order cumulant density (covariance density) is shown to be common to all the indices. Simulation studies were used to investigate the sampling variability of a single index based on the second-order cumulant. The simulations used a paired motoneurone model and a paired regular spiking cortical neurone model. The sampling variability of spike trains generated under identical conditions from the paired motoneurone model varied from 50% to 160% of the estimated value. On theoretical grounds, and on the basis of simulated data a rate dependence is present in all synchronization indices. The application of coherence and pooled coherence estimates to the issue of synchronization indices is considered. This alternative frequency domain approach allows an arbitrary number of spike train pairs to be evaluated for statistically significant differences, and combined into a single population measure. The pooled coherence framework allows pooled time domain measures to be derived, application of this to the simulated data is illustrated. Data from the cortical neurone model is generated over a wide range of firing rates (1-250 spikes/s). The pooled coherence framework correctly characterizes the sampling variability as not significant over this wide operating range. The broader applicability of this approach to multielectrode array data is briefly discussed

    Pollination services in the UK: how important are honeybees?

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    Pollination services are known to provide substantial benefits to human populations and agriculture in particular. Although many species are known to provide pollination services, honeybees (Apis mellifera) are often assumed to provide the majority of these services to agriculture. Using data from a range of secondary sources, this study assesses the importance of insect pollinated crops at regional and national scales and investigates the capacity of honeybees to provide optimal pollination services to UK agriculture. The findings indicate that insect pollinated crops have become increasingly important in UK crop agriculture and, as of 2007, accounted for 20% of UK cropland and 19% of total farmgate crop value. Analysis of honeybee hive numbers indicates that current UK populations are only capable of supplying 34% of pollination service demands even under favourable assumptions, falling from 70% in 1984. In spite of this decline, insect pollinated crop yields have risen by an average of 54% since 1984, casting doubt on long held beliefs that honeybees provide the majority of pollination services. Future land use and crop production patterns may further increase the role of pollination services to UK agriculture, highlighting the importance of measures aimed at maintaining both wild and managed species

    Building literacies in secondary school history: The specific contribution of academic writing support

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    This paper considers the specific role and effect of academic writing support in a secondary school Content and Language Integrated Learning (CLIL) context. After discussing the potential place for academic writing support in the ongoing process of fostering disciplinary literacy, we report on an experimental study in which 45 Spanish secondary school students received a short academic writing module as part of their history course. The descriptions/explanations written in their post-tests were generally found to be more complete, with more explicit discourse markers and with better textual organization than the pre-tests. We discuss the implications of this for students’ progress towards disciplinary literacy.Este estudio considera el papel específico y el efecto del apoyo a la escritura académica en un contexto AICLE de escuela secundaria. Después de analizar el lugar potencial que el apoyo a la escritura académica podría tener en el proceso continuo de promoción de la literacidad disciplinar, se presentan los resultados de un estudio experimental en el que 45 estudiantes españoles de la escuela secundaria recibieron un breve módulo de escritura académica como parte de su curso de historia. Las descripciones / explicaciones escritas en sus post-tests se consideraron generalmente más completas, con marcadores de discurso más explícitos y con una mejor organización textual que las pre-tests. Finalmente, se discuten las implicaciones de estos resultados para el desarrollo de la literacidad disciplinar por parte de los estudiantes

    Quantifying the value of ecosystem services: a case study of honeybee pollination in the UK

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    There is concern that insect pollinators, such as honey bees, are currently declining in abundance, and are under serious threat from environmental changes such as habitat loss and climate change; the use of pesticides in intensive agriculture, and emerging diseases. This paper aims to evaluate how much public support there would be in preventing further decline to maintain the current number of bee colonies in the UK. The contingent valuation method (CVM) was used to obtain the willingness to pay (WTP) for a theoretical pollinator protection policy. Respondents were asked whether they would be WTP to support such a policy and how much would they pay? Results show that the mean WTP to support the bee protection policy was £1.37/week/household. Based on there being 24.9 million households in the UK, this is equivalent to £1.77 billion per year. This total value can show the importance of maintaining the overall pollination service to policy makers. We compare this total with estimates obtained using a simple market valuation of pollination for the UK

    A systematic review of methods to predict weight trajectories in health economic models of behavioral weight management programs : the potential role of psychosocial factors

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    Objectives. There is limited evidence on the long-term effectiveness of behavioral weight management interventions, and thus, when conducting health economic modeling, assumptions are made about weight trajectories. The aims of this review were to examine these assumptions made about weight trajectories, the evidence sources used to justify them, and the impact of assumptions on estimated cost-effectiveness. Given the evidence that some psychosocial variables are associated with weight-loss trajectories, we also aimed to examine the extent to which psychosocial variables have been used to estimate weight trajectories and whether psychosocial variables were measured within cited evidence sources. Methods. A search of databases (Medline, PubMed, Cochrane, NHS Economic Evaluation, Embase, PSYCinfo, CINAHL, EconLit) was conducted using keywords related to overweight, weight management, and economic evaluation. Economic evaluations of weight management interventions that included modeling beyond trial data were included. Results. Within the 38 eligible articles, 6 types of assumptions were reported (weight loss maintained, weight loss regained immediately, linear weight regain, subgroup-specific trajectories, exponential decay of effect, maintenance followed by regain). Fifteen articles cited at least 1 evidence source to support the assumption reported. The assumption used affected the assessment of cost-effectiveness in 9 of the 19 studies that tested this in sensitivity analyses. None of the articles reported using psychosocial factors to estimate weight trajectories. However, psychosocial factors were measured in evidence sources cited by 11 health economic models. Conclusions. Given the range of weight trajectories reported and the potential impact on funding decisions, further research is warranted to investigate how psychosocial variables measured in trials can be used within health economic models to simulate heterogeneous weight trajectories and potentially improve the accuracy of cost-effectiveness estimates

    Riding the seismic waves: Re-blending teacher education in response to changing demands

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    Editors: G. Williams, P. Statham, N. Brown & B. Cleland ISBN Proceedings USB: 978-1-86295-644-5 published by the University of TasmaniaBlended learning plays an important role in many tertiary institutions but little has been written about the implementation of blended learning in times of adversity, natural disaster or crisis. This paper describes how, in the wake of the 22 February Canterbury earthquake, five teacher educators responded to crisis-driven changing demands and changing directions. Our narratives describe how blended learning provided students in initial teacher education programmes with some certainty and continuity during a time of civil emergency. The professional learning generated from our experiences provides valuable insights for designing and preparing for blended learning in times of crisis, as well as developing resilient blended learning programmes for the future

    Gender-specific changes in well-being in older people with coronary heart disease: evidence from the English Longitudinal Study of Ageing

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    Objectives: The objective of this study is to investigate gender-specific trajectories in well-being among older people with coronary heart disease (CHD) and to compare them with those of healthy people. Method: The study included a sample of 4496 participants from the first three waves of the English Longitudinal Study of Ageing (2002–2003 to 2006–2007). We measured well-being using quality of life (CASP-19; ‘control’, ‘autonomy’, ‘pleasure’ and ‘self-realization’) and depressive caseness (three or more symptoms on the CESD-8; Centre for Epidemiologic Study Depression scale). Results: After adjustment, at two– and four–years follow-ups, women had three points higher quality of life than men (p < 0.001). When looking at each quality of life's domain we found that women reported higher scores of autonomy compared to men. The gender difference in the probability of having depressive caseness reduced to 7 percentage points at four-year follow-up from 13 percentage points in the previous occasions. Men's quality of life declined progressively over time by 3 points (p < 0.001) (equivalent to the effect of having diabetes) but no changes in prevalence of depressive caseness were found. Women's quality of life only declined after four-year follow-up by less than 2 points (p < 0.001), while in the same period their probability of reporting depressive caseness reduced by 6 percentage points (p < 0.001). Conclusion: Women had better quality of life than men in the two and four years following a CHD event, and were not more likely than men to report depressive caseness in the long term. Men's quality of life deteriorated progressively over time, among women it did not deteriorate in the first two years following a CHD event; women had a long-term improvement in depressive caseness

    The impact of a local sugar sweetened beverage health promotion and price increase on sales in public leisure centre facilities

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    BACKGROUND: We aimed to evaluate the impact of a local sugar sweetened beverages (SSB) health promotion and 20p price increase in leisure centre venues and estimate the impact on consumption. METHOD: Monthly cold drinks sales data and attendance at leisure centres across the city of Sheffield were analysed over the period January 2015-July 2017. Interrupted time-series methods were employed to estimate changes in consumption per attendance of SSB and non-SSB cold drinks following the introduction of the SSB policy from August 2016 adjusting for seasonal variation and autocorrelation. SSB price elasticities were estimated with fixed effects log-log models by SSB product type (soda can, soda bottle, soda post mix, energy drinks, juice from concentrate). FINDINGS: We estimated a 31% (95% CI 4%, 59%) reduction in units of SSB sold per attendance in the year since the policy was introduced. We did not observe substitution effects to fruit juice or water but found sales of other artificially sweetened non-SSB products increased by 27% (95% CI 6%, 47%) after the introduction of the tax. Price elasticity analysis identified that a 1% increase in price alongside health promotion leads to a 3.8% (95% CI 3.1% 4.4%) decrease in demand for SSB's. Price elasticity of demand was highest for child friendly and high caffeine energy drinks. INTERPRETATION: Demand for SSB drinks at leisure centre venues is highly responsive to the policy, particularly for child-friendly and high caffeine energy drinks, compared with other SSB tax policy evaluations. The policy also increased purchases of carbonated non-SSB

    Continuous-wave room-temperature diamond maser

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    The maser, older sibling of the laser, has been confined to relative obscurity due to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this it has found application in deep-space communications and radio astronomy due to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solid- state maser exploiting photo-excited triplet states in organic pentacene molecules paves the way for a new class of maser that could find applications in medicine, security and sensing, taking advantage of its sensitivity and low noise. However, to date, only pulsed operation has been observed in this system. Furthermore, organic maser molecules have poor thermal and mechanical properties, and their triplet sub-level decay rates make continuous emission challenging: alternative materials are therefore required. Therefore, inorganic materials containing spin-defects such as diamond and silicon carbide have been proposed. Here we report a continuous-wave (CW) room-temperature maser oscillator using optically pumped charged nitrogen-vacancy (NV) defect centres in diamond. This demonstration unlocks the potential of room-temperature solid-state masers for use in a new generation of microwave devices.Comment: 7 pages, 4 figure
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