3,145 research outputs found

    A rational basis for second-kind Abel integral equations

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    AbstractA rational basis set is constructed using [1, 1] rational interpolation. The basis is used in a product integration method for solving second-kind Abel integral equations. Criteria are established for determining the amount of bias to be used in the basis set when the integral equation has a nonsmooth solution. Several test problems are solved to illustrate the performance of the approximation method

    Development and application of a catchment scale pesticide fate and transport model for use in drinking water risk assessment

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    This paper describes the development and application of IMPT (Integrated Model for Pesticide Transport), a parameter-efficient tool for predicting diffuse-source pesticide concentrations in surface waters used for drinking water supply. The model was applied to a small UK headwater catchment with high frequency (8 h) pesticide monitoring data and to five larger catchments (479–1653 km2) with sampling approximately every 14 days. Model performance was good for predictions of both flow (Nash Sutcliffe Efficiency generally > 0.59 and PBIAS < 10%) and pesticide concentrations, although low sampling frequency in the larger catchments is likely to mask the true episodic nature of exposure. The computational efficiency of the model, along with the fact that most of its parameters can be derived from existing national soil property data mean that it can be used to rapidly predict pesticide exposure in multiple surface water resources to support operational and strategic risk assessments

    Nakht-Min: Ramesses II's charioteer and envoy

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    The effectiveness of school-based run/walk programmes to develop physical literacy and physical activity components in primary school children: A systematic review

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    The objectives of this review were to systematically review the research on school-based run/walk programmes and their measurements of physical literacy (PL) and physical activity (PA)-related components and to assess the different intervention methods and their impact on encouraging PL and PA. To be included in the review, studies had to satisfy all inclusion criteria. An electronic search was conducted on six databases, the last date search was 25 April 2022. All outcome measures were grouped using the Shearer et al. (Citation2021) PL checklist and additional PA related outcomes. Ten studies were included in the final review. Five different run/walk interventions were identified and six studies followed or referred to The Daily Mile (TDM) protocol. Outcomes relating to the physical domain were most commonly explored, and no studies explored the cognitive domain. Four studies reported significant differences in cardiovascular endurance measures. Positive findings were also reported for outcomes relating to motivation and self-perception/self-esteem in the affective domain. Overall, run/walk programmes appear to provide promising results in favour of physical and affective development in PL. However, further high-quality studies are needed to draw firm conclusions. This review highlights the popularity of TDM and its potential to contribute to PL development

    Effect of production system and geographic location on milk quality parameters

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    A main reason for the rapid increase in organic food consumption is the perception that organic foods have a superior nutritional composition and/or convey health benefits. However, there is currently limited scientific knowledge about the effect of production systems on food composition. The study reported here compared fatty acid profiles and levels of fat soluble antioxidants in milk from organic and conventional production systems in 5 geographic regions in Europe (Wales, England, Denmark, Sweden and Italy). Levels of nutritionally desirable mono- and poly-unsaturated fatty acids (vaccenic acid, CLA, α-linolenic acid) and/or a range of fat soluble antioxidants were found to be significantly higher in organic milk

    Incorporating Special Needs Youth into 4-H

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    The Winning 4-H Plan provides Extension professionals, volunteers, parents, and youth with hands-on activities to improve their understanding of special needs youth and to promote inclusion of these youth in traditional 4-H programs. The program emphasizes acceptance by peers through an educational 4-H plan. When using appropriate project materials that follow a step-by-step progression, the end result will be a positive judging experience. The Winning 4-H Plan creates a 4-H environment where youth with disabilities can reach their fullest potential as capable, competent, caring, and contributing citizens

    Sustainable intensification? Increased production diminishes omega-3 content of sheep milk

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    Intensifying agricultural production alters food composition, but this is often ignored when assessing system sustainability, yet it could compromise consumers’ health and the concept of ‘sustainable diets’. Here we consider milk composition from Mediterranean dairy sheep, finding inferior fatty acid (FA) profiles with respect to consumer health as a result of a more intensive system of production. Semi-intensive management did produce 57% more milk per ewe with 20% lower fat content, but inferior fat composition. Milk had a nutritionally poorer fatty acid (FA) profile, with 18% less omega-3 FA (n-3) (19% less long-chain n-3) and 7% less monounsaturated FA but 3% more saturated FA (9% higher in C14:0) concentrations compared with ewes under traditional, extensive management. Redundancy analysis identified close associations between fat composition and animal diets, particularly concentrate supplementation and grazing cultivated pasture - n-3 was associated with grazing diverse, native mountain pastures. The paper questions if identifying such key elements in traditional systems could be deployed for ‘sustainable intensification’ to maintain food quality whilst increasing output

    ‘Works for some but not others’ A qualitative study on teachers’ perspectives and perceived pupil experience of a North West London school-based run/walk programme

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    Developing physical literacy (PL) in childhood is a key to develop lifelong physical activity. Teachers’ play an important role in supporting children’s PL and are at the forefront for continued participation in school-based interventions. This study aimed to discuss teacher-perceived pupils’ experiences of a London-based run/walk intervention and explore its contribution to PL. Semi-structured interviews were developed to explore school delivery and teacher perceptions. Six themes developed: perceived experiences, perceived outcomes of participation, teacher attitudes, fidelity/adherence, logistics and intervention suggestions. A novel insight is that the intervention ‘works for some but not others’ and the importance of self-select pace

    A non-linear optimal estimation inverse method for radio occultation measurements of temperature, humidity and surface pressure

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    An optimal estimation inverse method is presented which can be used to retrieve simultaneously vertical profiles of temperature and specific humidity, in addition to surface pressure, from satellite-to-satellite radio occultation observations of the Earth's atmosphere. The method is a non-linear, maximum {\it a posteriori} technique which can accommodate most aspects of the real radio occultation problem and is found to be stable and to converge rapidly in most cases. The optimal estimation inverse method has two distinct advantages over the analytic inverse method in that it accounts for some of the effects of horizontal gradients and is able to retrieve optimally temperature and humidity simultaneously from the observations. It is also able to account for observation noise and other sources of error. Combined, these advantages ensure a realistic retrieval of atmospheric quantities. A complete error analysis emerges naturally from the optimal estimation theory, allowing a full characterisation of the solution. Using this analysis a quality control scheme is implemented which allows anomalous retrieval conditions to be recognised and removed, thus preventing gross retrieval errors. The inverse method presented in this paper has been implemented for bending angle measurements derived from GPS/MET radio occultation observations of the Earth. Preliminary results from simulated data suggest that these observations have the potential to improve NWP model analyses significantly throughout their vertical range.Comment: 18 (jgr journal) pages, 7 figure

    Fitness differences suppress the number of mating types in evolving isogamous species

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    Sexual reproduction is not always synonymous with the existence of two morphologically different sexes; isogamous species produce sex cells of equal size, typically falling into multiple distinct self-incompatible classes, termed mating types. A long-standing open question in evolutionary biology is: what governs the number of these mating types across species? Simple theoretical arguments imply an advantage to rare types, suggesting the number of types should grow consistently; however, empirical observations are very different. While some isogamous species exhibit thousands of mating types, such species are exceedingly rare, and most have fewer than 10. In this paper, we present a mathematical analysis to quantify the role of fitness variation—characterized by different mortality rates—in determining the number of mating types emerging in simple evolutionary models. We predict that the number of mating types decreases as the variance of mortality increases
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