769 research outputs found

    Monitoring Productivity of A UK Dairy System Aiming to Increase Soil Carbon, based on Diverse Swards and Incorporating Mob Grazing

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    There is interest in increasing soil organic matter (SOM), both to improve plant productivity, and augment carbon sequestration. One practice that may contribute to increasing SOM is a “mob grazing” approach. This involves high stocking density for a short period of time, and often grazing more mature swards, leaving higher cover and longer recovery times between grazings than is typical in the UK. This approach is likely to be best suited to swards that include a wide variety of grass and herb species, giving greater resilience than a purely ryegrass sward. The performance of dairy herds on such swards under this type of management in the UK has not been documented. This paper describes how a participatory approach is used to gather sward and animal production data from a farm where diverse swards and a “mob grazing” system have been developed over seven years, with the aim of increasing the return of organic matter to the soil

    Contextual Chemistry and Physics Teaching in an Undergraduate Nanotechnology Degree

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    Curtin University established a Bachelor of Science (Nanotechnology) degree in 2002 as a jointprogram between the departments of Applied Chemistry and Applied Physics. This paper describesthe structure of the degree and the approaches taken in the development of a stream ofnanotechnology units aimed at enhancing the teaching of fundamental concepts in Physics andChemistry within a Nanotechnology context. Student perceptions of the value of thesenanotechnology units are also discussed

    The isomorphism problem for Schubert varieties

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    Schubert varieties in the full flag variety of Kac-Moody type are indexed by elements of the corresponding Weyl group. We give a practical criterion for when two such Schubert varieties (from potentially different flag varieties) are isomorphic, in terms of the Cartan matrix and reduced words for the indexing Weyl group elements. As a corollary, we show that two such Schubert varieties are isomorphic if and only if there is an isomorphism between their integral cohomology rings that preserves the Schubert basis.Comment: 23 pages, 1 figur

    Staircase diagrams and the enumeration of smooth Schubert varieties

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    International audienceIn this extended abstract, we give a complete description and enumeration of smooth and rationally smooth Schubert varieties in finite type. In particular, we show that rationally smooth Schubert varieties are in bijection with a new combinatorial data structure called staircase diagrams

    Letters between Fred Richmond and W. J. Kerr

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    Letters concerning a student position at the Utah Agricultural College

    Simulation of iron oxide/silica precipitation in the paragoethite process for the removal of iron from acidic zinc leach solutions

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    An investigation of the simultaneous precipitation of iron oxide and silica species from acidic solutions was conducted, simulating the Paragoethite Process, an iron-removal stage employed in zinc hydrometallurgy. Laboratory-based continuous crystallisation experiments were carried under the primary conditions employed in industry, with pH (at 85°C) maintained at 2.65, the combined Fe and Si concentration at 0.1128 M (unless otherwise stated) and Si:Fe ratios varied from 0 to 0.43. The crystal structure of the residues produced was characterised, with the extent of iron and silicate removal quantified and properties relating to aggregate structure also measured. It is shown that the degree of silica polymerisation prior to the precipitation reaction dictates the mechanism of co-precipitation and thereby the properties of the residue. In the presence of polymerised silica, less dense aggregates of finer mean particle size are formed, which has negative implications for dewatering. Conversely, where silica is allowed to polymerise prior to the iron precipitation reaction, a greater proportion of silica is removed from solution. Close control of silica polymerisation in the feed liquor is therefore required to reach a compromise between its beneficial and detrimental influences, and to thereby obtain optimal performance

    Foraging ecology of the Philippine flying lemur (Cynocephalus volans)

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    Between August 1986 and September 1987, six Philippine flying lemurs (Cynocephalus volans) were observed foraging on 35 of 76 available species of trees, representing ≥12 families of ≥26 available families. Eight species were foraged on in amounts significantly greater than expected, given the tree\u27s abundance on the study area, and four were foraged on significantly less than expected. The foraging strategy of C. volans involved foraging many times during the night, for short duration, in several different species of tree each night. This strategy differed from that of other arboreal folivores
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