10,196 research outputs found

    Identification Of Environmental Variables For Use In Monitoring For The Evaluation Of The Rural Environment Protection Scheme

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    Teagasc wishes to acknowledge the support of the Environmental RTDI Programme 2000–2006 in financing this research project.End of project reportThe aim of this study was to identify and select quantitative environmental attributes for a monitoring programme that may be integrated into an environmental evaluation of Ireland’s agri-environmental scheme. This was achieved primarily by reviewing a range of agri-environmental indicators and suggesting indicators that would be appropriate for monitoring the REPS. The study conducted a desk review to collate information on current best practice in monitoring for environmental quality. A Project Group (comprising representatives from the Environmental Protection Agency [EPA], Department of Agriculture and Food [DAF], Teagasc, and the project supervisors) advised on the ongoing development of the project. There was a consultation process with national experts, and with a selection of stakeholder organisations with an interest in monitoring the environmental impact of the REPS.Environmental Protection Agenc

    A model for the anisotropic response of fibrous soft tissues using six discrete fibre bundles

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    The development of accurate constitutive models of fibrous soft-tissues is a challenging problem. Many consider the tissue to be a collection of fibres with a continuous distribution function representing their orientations. A novel discrete fibre model is presented consisting of six weighted fibre bundles. Each bundle is oriented such that they pass through opposing vertices of a regular icosahedron. A novel aspect of the model is the use of simple analytical distribution functions to simulate the undulated collagen fibres. This approach yields a closed form analytical expression for the strain energy function for the collagen fibre bundle that avoids the sometimes costly numerical integration of some statistical distribution functions. The elastin fibres are characterized by a neo-Hookean strain energy function. The model accurately simulates the biaxial stretching of rabbit-skin (error-of-fit 8.7%), the uniaxial stretching of pig-skin (error-of-fit 7.6%), equibiaxial loading of aortic valve cusp (error-of-fit 0.8%), and the simple shear of rat septal myocardium (error-of-fit 9.1%). The proposed model compares favourably with previously published soft-tissue models and alternative methods of representing undulated collagen fibres. The stiffness of collagen fibres predicted by the model ranges from 8.0 MPa to 0.93 GPa. The stiffness of elastin fibres ranges from 2.5 kPa to 154.4 kPa. The anisotropy of model resulting from the representation of the fibre field with a discrete number of fibres is also explored

    Galactic Archaeology and Minimum Spanning Trees

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    Chemical tagging of stellar debris from disrupted open clusters and associations underpins the science cases for next-generation multi-object spectroscopic surveys. As part of the Galactic Archaeology project TraCD (Tracking Cluster Debris), a preliminary attempt at reconstructing the birth clouds of now phase-mixed thin disk debris is undertaken using a parametric minimum spanning tree (MST) approach. Empirically-motivated chemical abundance pattern uncertainties (for a 10-dimensional chemistry-space) are applied to NBODY6-realised stellar associations dissolved into a background sea of field stars, all evolving in a Milky Way potential. We demonstrate that significant population reconstruction degeneracies appear when the abundance uncertainties approach 0.1 dex and the parameterised MST approach is employed; more sophisticated methodologies will be required to ameliorate these degeneracies.Comment: To appear in "Multi-Object Spectroscopy in the Next Decade: Big Questions, Large Surveys and Wide Fields"; Held: Santa Cruz de La Palma, Canary Islands, Spain, 2-6 Mar 2015; ed. I Skillen & S. Trager; ASP Conference Series (Figures now optimised for B&W printing

    Are all fast radio bursts repeating sources?

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    We present Monte-Carlo simulations of a cosmological population of repeating fast radio burst (FRB) sources whose comoving density follows the cosmic star formation rate history. We assume a power-law model for the intrinsic energy distribution for each repeating FRB source located at a randomly chosen position in the sky and simulate their dispersion measures (DMs) and propagation effects along the chosen lines-of-sight to various telescopes. In one scenario, an exponential distribution for the intrinsic wait times between pulses is chosen, and in a second scenario we model the observed pulse arrival times to follow a Weibull distribution. For both models we determine whether the FRB source would be deemed a repeater based on the telescope sensitivity and time spent on follow-up observations. We are unable to rule out the existence of a single FRB population based on comparisons of our simulations with the longest FRB follow-up observations performed. We however rule out the possibility of FRBs 171020 and 010724 repeating with the same rate statistics as FRB 121102 and also constrain the slope of a power-law fit to the FRB energy distribution to be −2.0<γ<−1.0-2.0 < \gamma <-1.0. All-sky simulations of repeating FRB sources imply that the detection of singular events correspond to the bright tail-end of the adopted energy distribution due to the combination of the increase in volume probed with distance, and the position of the burst in the telescope beam.Comment: 10 pages, 4 figures, accepted for publication in MNRA

    The arithmetic of hyperelliptic curves

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    We summarise recent advances in techniques for solving Diophantine problems on hyperelliptic curves; in particular, those for finding the rank of the Jacobian, and the set of rational points on the curve

    Supply Chain Structure, Inventory Turnover, and Financial Performance: Evidence from Manufacturing Companies in China

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    Using data collected by the World Bank, we empirically investigate the relationship between Chinese manufacturers’ supply chain attributes, raw material and finished goods inventory turnover, and return on sales. Our findings indicate that location proximity, relationship continuity, and the relative power of the manufacturer over suppliers and customers have a significant impact on inventory performance, which in turn drives profitability. We especially focus on characteristics unique to China’s business environment. We find that Chinese manufacturing companies have relatively weak operational performance, and better operational performance is associated with closer distance, longer relationship with suppliers and customers, and relative power over suppliers. Unlike their counter parties in some developed countries, Chinese manufacturers’ profitability relies on both downstream and upstream inventory performance, with downstream inventory performance playing a somewhat more important role

    Special Topic Forum on Supply Chain Management in Emerging Markets: Critical Research Issues

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    Spurred by the rapid development of international markets, w enhanced ease of communications and rapidly developing infrastructure, supply chains that transcend national boundaries have become standard in today's dynamic global environment, causing a number of critical research issues to emerge. The importance of such issues is intensified when considered in the unique environment faced by supply chains in emerging economies, such as Brazil, Russia, India and China. Traditional supply chain management practices may be ineffective, due to the unique characteristics of supply chains in emerging economies or that span developed and emerging economies. In this special topic forum, we seek high quality conceptual and empirical research that addresses critical research issues related to managing supply chains in emerging economies. Conceptual papers should draw upon and extend existing theoretical foundations, developing models and propositions for future research. Empirical research studies that employ survey methodology, structured case research, secondary data analysis, controlled experiments and other empirical approaches are welcomed. In line with JSCM's mission statement, authors must clearly identify how their work extends or contributes to theory relating to global supply chain management, as well as providing implications for practice

    Operational Capabilities: The Secret Ingredient

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    We develop a theoretical definition of operational capabilities, based on the strategic management and operations management literature, and differentiate this construct from the related constructs of resources and operational practices, drawing upon the resourcebased view of the firm as our foundation. We illustrate the key features of operational capabilities using the illustration of a restaurant kitchen. Because the traits of operational capabilities are distinct, they create a barrier to imitation, making them a potential source of competitive advantage. However, operational capabilities are particularly challenging to measure, because they emerge gradually and are tacit, embedded, and manifested differently across firms. In solving this measurement conundrum, we draw upon similar situations experienced by Schein (2004) and Eisenhardt and Martin (2000) in operationalizing organizational culture and dynamic capabilities. A taxonomy of six emergent operational capabilities is developed: operational improvement, operational innovation, operational customization, operational cooperation, operational responsiveness, and operational reconfiguration. A set of measurement scales is developed, in order to measure each of the operational capabilities, and validated using two different datasets. This allows replication of the psychometric properties of the multi-item scales and helps to ensure the validity of the resulting measures
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