799 research outputs found

    Econometric and time series models for predicting the futures market basis for Tennessee feeder cattle

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    The purpose of this study was to develop forecasting models capable of predicting basis for Tennessee feeder cattle six months in advance. Both econometric and time series models were developed, estimated and tested out-of-sample. The econometric model was estimated using five continuous inde-pendent variables. These were: transfer cost, futures price level, feeder cattle supply, stage of the cattle cycle and local grazing conditions. Dummy variables were used to represent the futures contract change to a cash settlement system and to represent the seasonality of feeder cattle production and marketing. The first type of time series model used was a univariate ARIMA model. Two ARIMA model specifications were used in the study, both of which accounted for seasonal components in the autoregressive scheme. Transfer function models were the second type of time series models used. Two forms of transfer function models were used with each including the futures contract change dummy variable in addition to seasonal autoregressive components. The second transfer function also used a transportation cost index as an exogenous variable. The five models were used to predict values for 12 10-day market-ing periods out-of-sample. These forecasts were compared to actual values using Theil\u27s U2 coefficient, root mean square error and graphics. Four models were able to predict better than a naive no-price-change model as indicated by coefficients less than one. Values for the U2 coefficients ranged from 0.28 to 1.12 and the cor-responding RMSE ranged from 0.87to0.87 to 3.49. The transfer function model with the dummy variable to represent the futures contract change to cash settlement and the transportation cost index was the superior model based on the above criteria. The econometric model was second best and the transfer function model with only the cash settlement dummy variable ranked third. The pure time series models ranked fourth and fifth, consistently overestimating the Tennessee feeder cattle basis

    Behavioural responses of a large, benthic elasmobranch to catch-and-release angling

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    Funding: This work was supported by a PhD Studentship at the University of St Andrews, jointly funded by NatureScot via the Marine Alliance for Science and Technology for Scotland (MASTS), and the Centre for Research into Ecological and Environmental Modelling. Data were collected as part of research funded by NatureScot (project 015960) and Marine Scotland (projects SP004 and SP02B0) via the Movement Ecology of Flapper Skate project. Additional funding was provided from MASTS and Shark Guardian.Catch-and-release angling is widespread, but the impacts of this practice for captured individuals are understudied, especially among elasmobranchs. Studies on sub-lethal behavioural impacts are particularly sparse, despite their importance for the interpretation of biologging data and for assessments of species’ tolerance to capture. In this study, the behavioural responses of flapper skate (Dipturus intermedius) to catch-and-release angling were described for the first time, using archival observations (depth and temperature) for 21 tag deployment/retrieval events and five recreational angling events that occurred during tagged individuals’ time at liberty from charter vessels off the west coast of Scotland in 2016–17. During capture (8–50 minutes), the changes in depth and temperature experienced by individuals typically exceeded natural variability. Post-release, behavioural change was apparent from visual inspection, regression and functional data analysis of the time series. Immediately following release, movements into deeper water and short periods of low vertical activity (usually 1–2 hours in duration) were common. However, overall average vertical activity was typically around 38% higher in the 12 hours following release than in undisturbed activity. A small number of individuals (n = 3, 14%) exhibited irregular post-release behaviour in the form of rapid, transient re-ascents towards the surface following release. Collectively, the evidence for limited, short-term behavioural changes suggests that flapper skate behaviour is relatively resilient to catch-and-release angling from charter vessels, but irregular post-release behaviour in 14% of individuals is sufficiently notable to indicate that further research is required on the impacts of this practice. This study clearly demonstrates the value of biologging data and behavioural analyses for examining the impacts of disturbance and separating ‘disturbed’ and ‘undisturbed’ behaviours in studies of animal movement.Publisher PDFPeer reviewe

    Seasonal and ontogenetic variation in depth use by a critically endangered benthic elasmobranch and its implications for spatial management

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    The project was undertaken through the Movement Ecology of the Flapper skate project at St Andrews and received support from the Ecology and Conservation Group, Marine Scotland Science, and Marine Scotland Planning & Policy and NatureScot. It was funded by Marine Scotland projects SP004 and SP02B0 and NatureScot project 015960.Seasonal and ontogenetic variation in depth use by benthic species are often concomitant with changes in their spatial distribution. This has implications for the efficacy of spatial conservation measures such as Marine Protected Areas (MPAs). The critically endangered flapper skate (Dipturus intermedius) is the designation feature of an MPA in Scotland. This species is generally associated with deeper waters >100 m; however, little is known about its seasonal or ontogenetic variation in habitat use. This study used archival depth data from 25 immature and mature flapper skate tagged in the MPA over multiple years. Time series ranged from 3 to 772 (mean = 246) days. Generalised additive mixed models and highest density intervals were used to identify home (95%) and core (50%) highest density depth regions (HDDRs) to quantify depth use in relation to time of year and body size. Skate used a total depth range of 1 – 312 m, but home HDDRs typically occurred between 20 – 225 m. Core HDDRs displayed significant seasonal and ontogenetic variation. Summer core HDDRs (100 – 150 m) suggest high occupancy of the deep trenches in the region by skate of most size classes. There was an inverse relationship between body size and depth use, and a seasonal trend of skate moving into shallow water over winter months. These results suggest flapper skate are not solely associated with deep water, as skate, especially large females, are frequently found in shallow waters (25 – 75 m). The current management, which protects the entire depth range, is appropriate for the protection of flapper skate through much of its life-history. This research demonstrates why collecting data across seasonal scales and multiple ontogenetic stages is needed to assess the effectiveness of spatial management.Publisher PDFPeer reviewe

    Mental Well-Being in UK Higher Education During Covid-19: Do Students Trust Universities and the Government?

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    This paper draws upon the concept of recreancy to examine the mental well-being of university students during the Covid-19 pandemic. Briefly, recreancy is loss of societal trust that results when institutional actors can no longer be counted on to perform their responsibilities. Our study of mental well-being and recreancy focuses on the role of universities and government regulators within the education sector. We surveyed 600 UK students attending 161 different public higher education providers in October 2020 during a time when many UK students were isolated in their residences and engaged in online learning. We assessed student well-being using the Short Warwick-Edinburgh Mental Well-being Scale (scored 7–35) and found the mean score to be 19.9 [95% confidence interval (CI) 19.6, 20.2]. This level of well-being indicates that a significant proportion of UK students face low levels of mental well-being. Structural equation modeling (SEM) analysis indicates that high recreancy—measured as a low trust in universities and the government—is associated with low levels of mental well-being across the student sample. While these findings are suggestive, they are also important and we suggest that government and university leaders should not only work to increase food and housing security during the Covid-19 pandemic, but also consider how to combat various sector trends that might intensify recreancy

    Measuring Controlled-NOT and two-qubit gate operation

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    Accurate characterisation of two-qubit gates will be critical for any realisation of quantum computation. We discuss a range of measurements aimed at characterising a two-qubit gate, specifically the CNOT gate. These measurements are architecture-independent, and range from simple truth table measurements, to single figure measures such as the fringe visibility, parity, fidelity, and entanglement witnesses, through to whole-state and whole-gate measures achieved respectively via quantum state and process tomography. In doing so, we examine critical differences between classical and quantum gate operation.Comment: 10 pages (two-column). 1 figur

    Adaptation to chronic drought modifies soil microbial community responses to phytohormones

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    Drought imposes stress on plants and associated soil microbes, inducing coordinated adaptive responses, which can involve plant–soil signalling via phytohormones. However, we know little about how microbial communities respond to phytohormones, or how these responses are shaped by chronic (long-term) drought. Here, we added three phytohormones (abscisic acid, 1-aminocyclopropane-1-carboxylic acid, and jasmonic acid) to soils from long-term (25-year), field-based climate treatments to test the hypothesis that chronic drought alters soil microbial community responses to plant stress signalling. Phytohormone addition increased soil respiration, but this effect was stronger in irrigated than in droughted soils and increased soil respiration at low phytohormone concentrations could not be explained by their use as substrate. Thus, we show that drought adaptation within soil microbial communities modifies their responses to phytohormone inputs. Furthermore, distinct phytohormone-induced shifts in microbial functional groups in droughted vs. irrigated soils might suggest that drought-adapted soil microorganisms perceive phytohormones as stress-signals, allowing them to anticipate impending drought

    Community-based monitoring of Indigenous food security in a changing climate: global trends and future directions

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    Climate change is expected to exacerbate existing food security challenges, especially in Indigenous communities worldwide. Community-based monitoring (CBM) is considered a promising strategy to improve monitoring of, and local adaptation to climatic and environmental change. Yet, it is unclear how this approach can be applied in food security or Indigenous contexts. The objectives of this paper are to: (1) review and synthesize the published literature on CBM of Indigenous food security; and, (2) identify gaps and trends in these monitoring efforts in the context of climate change. Using a systematic search and screening process, we identified 86 published articles. To be included, articles had to be published in a journal, describe a CBM system, describe any aspect of food security, and explicitly mention an Indigenous community. Relevant articles were thematically analyzed to characterize elements of CBM in the context of climate change. Results show that the number of articles published over time was steady and increased more than two-fold within the last five years. The reviewed articles reported on monitoring mainly in North America (37%) and South America (28%). In general, monitoring was either collaborative (51%) or externally-driven (37%), and focused primarily on tracking wildlife (29%), followed by natural resources (16%), environmental change (15%), fisheries (13%), climate change (9%), or some combination of these topics (18%). This review provides an evidence-base on the uses, characteristics, and opportunities of CBM, to guide future food security monitoring efforts in the context of climate change

    Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes.

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    Ketosis, the metabolic response to energy crisis, is a mechanism to sustain life by altering oxidative fuel selection. Often overlooked for its metabolic potential, ketosis is poorly understood outside of starvation or diabetic crisis. Thus, we studied the biochemical advantages of ketosis in humans using a ketone ester-based form of nutrition without the unwanted milieu of endogenous ketone body production by caloric or carbohydrate restriction. In five separate studies of 39 high-performance athletes, we show how this unique metabolic state improves physical endurance by altering fuel competition for oxidative respiration. Ketosis decreased muscle glycolysis and plasma lactate concentrations, while providing an alternative substrate for oxidative phosphorylation. Ketosis increased intramuscular triacylglycerol oxidation during exercise, even in the presence of normal muscle glycogen, co-ingested carbohydrate and elevated insulin. These findings may hold clues to greater human potential and a better understanding of fuel metabolism in health and disease

    The impact of sex on severe asthma: a cross-sectional retrospective analysis of UK primary and specialist care:a cross-sectional retrospective analysis of UK primary and specialist care

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    After puberty, females are more likely to develop asthma and in a more severe form than males. The associations between asthma and sex are complex with multiple intrinsic and external factors. To evaluate the sex differences in the characteristics and treatment of patients with severe asthma (SA) in a real-world setting. Demographic, clinical and treatment characteristics for patients with SA in the UK Severe Asthma Registry (UKSAR) and Optimum Patient Care Research Database (OPCRD) were retrospectively analysed by sex using univariable and multivariable logistic regression analyses adjusted for year, age and hospital/practice. 3679 (60.9% female) patients from UKSAR and 18 369 patients (67.9% female) from OPCRD with SA were included. Females were more likely to be symptomatic with increased Asthma Control Questionnaire-6 (UKSAR adjusted OR (aOR) 1.14, 95% CI 1.09 to 1.18) and Royal College of Physicians-3 Question scores (OPCRD aOR 1.29, 95% CI 1.13 to 1.47). However, they had a higher forced expiratory volume in 1 second per cent (FEV %) predicted (UKSAR 68.7% vs 64.8%,
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