396 research outputs found

    Environmental assessment tools for the evaluation and improvement of European livestock production systems

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    Different types of assessment tools have been developed in Europe with the purpose of determining the environmental impact of various livestock production systems at farm level. The assessment tools differ in terms of which environmental objectives are included and how indicators are constructed and interpreted. The paper compares typical tools for environmental assessment of livestock production systems, and recommends selected indicators suitable for benchmarking. The assessment tools used very different types of indicators ranging from descriptions of farm management and quantification of input to estimates of emissions of, e.g., nitrate and ammonia. The indicators should be useful in a benchmarking process where farmers may improve their practices through learning from farms with better agri-environmental performance. An example of this is given using data on P-surplus on pig farms. Some indicators used the area of the farm as the basis of the indicator — e.g. nitrogen surplus per hectare — while others were expressed per unit produced, e.g. emission of greenhouse gasses per kilogram milk. The paper demonstrates that a comparison of organic vs. conventional milk production and comparison of three pig production systems give different results, depending on the basis of the indicators (i.e. per hectare or per kilogram product). Indicators linked to environmental objectives with a local or regional geographical target should be area-based — while indicators with a global focus should be product-based. It is argued that the choice of indicators should be linked with the definition of the system boundaries, in the sense that area-based indicators should include emissions on the farm only, whereas product-based indicators should preferably include emissions from production of farm inputs, as well as the inputs on the actual farm. The paper ends with recommendations for choice of agri-environmental indicators taking into account the geographical scale, system boundary and method of interpretation

    Palaeoflow and Sediment Delivery Reconstructions from Martian Delta Morphology by Combined Modelling and HRSC DTM Analysis

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    have been formed by sapping. On the left of the delta there is a second lobe that may have formed as an initial drowned delta or alluvial fan. Summary: The size and shape of alluvial fans and deltas contain information on their formative time scale, sediment supply and the amount of water involved. A new numerical morphological model is presented that allows quantitative comparison of morphological predictions and HRSC DTMdata of six deltas. As morphology is uniquely coupled to water and sediment flux, the model also discriminates between dense flows (slurries) and dilute flows (rivers). We demonstrate that two Gilbert (Fig. 1) and three stepped fan deltas may have formed by dilute flows into filling lakes in less than 10 years. Introduction: Alluvial fans and deltas on Mars record past hydrological conditions. Until now these conditions were inferre

    Heart failure with preserved ejection fraction in humans and mice:Embracing clinical complexity in mouse models

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    Heart failure (HF) with preserved ejection fraction (HFpEF) is a multifactorial disease accounting for a large and increasing proportion of all clinical HF presentations. As a clinical syndrome, HFpEF is characterized by typical signs and symptoms of HF, a distinct cardiac phenotype and raised natriuretic peptides. Non-cardiac comorbidities frequently co-exist and contribute to the pathophysiology of HFpEF. To date, no therapy has proven to improve outcomes in HFpEF, with drug development hampered, at least partly, by lack of consensus on appropriate standards for pre-clinical HFpEF models. Recently, two clinical algorithms (HFA-PEFF and H(2)FPEF scores) have been developed to improve and standardize the diagnosis of HFpEF. In this review, we evaluate the translational utility of HFpEF mouse models in the context of these HFpEF scores. We systematically recorded evidence of symptoms and signs of HF or clinical HFpEF features and included several cardiac and extra-cardiac parameters as well as age and sex for each HFpEF mouse model. We found that most of the pre-clinical HFpEF models do not meet the HFpEF clinical criteria, although some multifactorial models resemble human HFpEF to a reasonable extent. We therefore conclude that to optimize the translational value of mouse models to human HFpEF, a novel approach for the development of pre-clinical HFpEF models is needed, taking into account the complex HFpEF pathophysiology in humans

    Increased efficiency of luminescent solar concentrators after application of organic wavelength selective mirrors

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    Organic wavelength-selective mirrors are used to reduce the loss of emitted photons through the surface of a luminescent solar concentrator (LSC). A theoretical calculation suggests that application of a 400 nm broad reflector on top of an LSC containing BASF Lumogen Red 305 as a luminophore can reflect 91% of all surface emitted photons back into the device. Used in this way, such broad reflectors could increase the edge-emission efficiency of the LSC by up to 66%. Similarly, 175 nm broad reflectors could increase efficiency up to 45%. Measurements demonstrate more limited effectiveness and dependency on the peak absorbance of the LSC. At higher absorbance, the increased number of internal re-absorption events reduces the effectiveness of the reflectors, leading to a maximum increase in LSC efficiency of ~5% for an LSC with a peak absorbance of 1. Reducing re-absorption by reducing dye concentration or the coverage of the luminophore coating results in an increase in LSC efficiency of up to 30% and 27%, respectively

    Het nieuwe telen Gerbera - Teeltseizoen: 2009-2010

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    De doelstelling van het project Het Nieuwe Telen Gerbera is het realiseren van een aanzienlijke energiebesparing met gelijkblijvende productie en kwaliteit. Dit onderzoek is uitgevoerd door de Flori Consult Group en WUR Glastuinbouw bij GreenQ-Improvement Centre in Bleiswijk

    Теплофизические модели слоисто-неоднородных горных массивов

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    Стисло розглянуто математичні моделі процесів переносу тепла в шаруватонеоднорідних гірничих масивах. Запропоновано загальний метод моделювання теплопереносу в шаруватих системах різної геометрії. Знайдено рівняння «склеювання», за допомогою якого розглянуто асимптотичні випадки.Mathematical models of heat transfer in layered inhomogeneous rock media are summarized. A general method of modeling the heat transfer in layered systems of a different geometry is proposed. A “matching” equation for different asymptotic cases has been found

    Two-hadron semi-inclusive production including subleading twist

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    We extend the analysis of two-hadron fragmentation functions to the subleading twist, discussing also the issue of color gauge invariance. Our results can be used anywhere two unpolarized hadrons are semi-inclusively produced in the same fragmentation region, also at moderate values of the hard scale Q. Here, we consider the example of polarized deep-inelastic production of two hadrons and we give a complete list of cross sections and spin asymmetries up to subleading twist. Among the results, we highlight the possibility of extracting the transversity distribution with longitudinally polarized targets and also the twist-3 distribution e(x), which is related to the pion-nucleon sigma term and to the strangeness content of the nucleon.Comment: 16 pages, RevTeX4, 5 figures, revised notation of several formulae, added text in Secs. III-V, added reference

    The Higher Derivative Expansion of the Effective Action by the String Inspired Method. Part II

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    We apply the string inspired worldline formalism to the calculation of the higher derivative expansion of one-loop effective actions in non-Abelian gauge theory. For this purpose, we have completely computerized the method, using the symbolic manipulation programs FORM, PERL and M. Explicit results are given to sixth order in the inverse mass expansion, reduced to a minimal basis of invariants specifically adapted to the method. Detailed comparisons are made with other gauge-invariant algorithms for calculating the same expansion. This includes an explicit check of all coefficients up to fifth order.Comment: 37 pages, LaTeX, 3 figures, typos corrected, to appear in Ann. Phys. (N.Y.
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