324 research outputs found

    Parametrization of semi-dynamical quantum reflection algebra

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    We construct sets of structure matrices for the semi-dynamical reflection algebra, solving the Yang-Baxter type consistency equations extended by the action of an automorphism of the auxiliary space. These solutions are parametrized by dynamical conjugation matrices, Drinfel'd twist representations and quantum non-dynamical RR-matrices. They yield factorized forms for the monodromy matrices.Comment: LaTeX, 24 pages. Misprints corrected, comments added in Conclusion on construction of Hamiltonian

    How Covid-19 has changed language assessments in higher education: a practitioners’ view

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    This chapter examines the responses of Higher Education Institutions (HEIs) to assessment-related challenges introduced by the Covid-19 pandemic. The sudden move to online teaching and assessments required institutions to re-think their approaches to current practices and provide alternative solutions almost overnight. Our survey aimed to gather the perceptions of language teaching practitioners on how the languages sector dealt with the move to digital assessments, with particular emphasis on the delivery of online assessments, the impact on different language skills, as well as academic integrity. Results show that, whilst different institutions adopted varying practices, they seem to share similar concerns in addressing the fast-changing environment and ensure that academic integrity remains at the forefront in the move to the digital world

    A novel microdosimeter based upon artificial single crystal diamond

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    Structures in BC_N Ruijsenaars-Schneider models

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    We construct the classical r-matrix structure for the Lax formulation of BC_N Ruijsenaars-Schneider systems proposed in hep-th 0006004. The r-matrix structure takes a quadratic form similar to the A_N Ruijsenaars-Schneider Poisson bracket behavior, although the dynamical dependence is more complicated. Commuting Hamiltonians stemming from the BC_N Ruijsenaars-Schneider Lax matrix are shown to be linear combinations of particular Koornwinder-van Diejen ``external fields'' Ruijsenaars-Schneider models, for specific values of the exponential one-body couplings. Uniqueness of such commuting Hamiltonians is established once the first of them and the general analytic structure are given.Comment: 18 pages, gzip latex fil

    An assessment of nitrification inhibitors to reduce nitrous oxide emissions from UK agriculture

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    A trial was conducted consisting of 14 experiments across sites in England of contrasting soil type and annual rainfall to assess the effectiveness of nitrification inhibitors (predominantly dicyandiamide (DCD) but limited assessment also of 3, 4-dimethylpyrazole phosphate (DMPP) and a commercial product containing two pyrazole derivatives) in reducing direct nitrous oxide (N _2 O) emissions from fertilizer nitrogen (N), cattle urine and cattle slurry applications to land. Measurements were also made of the impact on ammonia (NH _3 ) volatilization, nitrate (NO _3 ^− ) leaching, crop yield and crop N offtake. DCD proved to be very effective in reducing direct N _2 O emissions following fertilizer and cattle urine applications, with mean reduction efficiencies of 39, 69 and 70% for ammonium nitrate, urea and cattle urine, respectively. When included with cattle slurry a mean, non-significant reduction of 56% was observed. There were no N _2 O emission reductions observed from the limited assessments of the other nitrification inhibitors. Generally, there were no impacts of the nitrification inhibitors on NH _3 volatilization, NO _3 ^− leaching, crop yield or crop N offtake. Use of DCD could give up to 20% reduction in N _2 O emissions from UK agriculture, but cost-effective delivery mechanisms are required to encourage adoption by the sector. Direct N _2 O emissions from the studied sources were substantially lower than IPCC default values and development of UK country-specific emission factors for use in inventory compilation is warranted

    Spin chains from dynamical quadratic algebras

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    We present a construction of integrable quantum spin chains where local spin-spin interactions are weighted by ``position''-dependent potential containing abelian non-local spin dependance. This construction applies to the previously defined three general quadratic reflection-type algebras: respectively non-dynamical, semidynamical, fully dynamical.Comment: 12 pages, no figures; v2: corrected formulas of the last sectio

    Comparison of codes assessing galactic cosmic radiation exposure of aircraft crew

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    The assessment of the exposure to cosmic radiation onboard aircraft is one of the preoccupations of bodies responsible for radiation protection. Cosmic particle flux is significantly higher onboard aircraft than at ground level and its intensity depends on the solar activity. The dose is usually estimated using codes validated by the experimental data. In this paper, a comparison of various codes is presented, some of them are used routinely, to assess the dose received by the aircraft crew caused by the galactic cosmic radiation. Results are provided for periods close to solar maximum and minimum and for selected flights covering major commercial routes in the world. The overall agreement between the codes, particularly for those routinely used for aircraft crew dosimetry, was better than ±20 % from the median in all but two cases. The agreement within the codes is considered to be fully satisfactory for radiation protection purpose

    Inhibiting LXRα phosphorylation in hematopoietic cells reduces inflammation and attenuates atherosclerosis and obesity in mice

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    Atherosclerosis and obesity share pathological features including inflammation mediated by innate and adaptive immune cells. LXRα plays a central role in the transcription of inflammatory and metabolic genes. LXRα is modulated by phosphorylation at serine 196 (LXRα pS196), however, the consequences of LXRα pS196 in hematopoietic cell precursors in atherosclerosis and obesity have not been investigated. To assess the importance of LXRα phosphorylation, bone marrow from LXRα WT and S196A mice was transplanted into Ldlr-/- mice, which were fed a western diet prior to evaluation of atherosclerosis and obesity. Plaques from S196A mice showed reduced inflammatory monocyte recruitment, lipid accumulation, and macrophage proliferation. Expression profiling of CD68+ and T cells from S196A mouse plaques revealed downregulation of pro-inflammatory genes and in the case of CD68+ upregulation of mitochondrial genes characteristic of anti-inflammatory macrophages. Furthermore, S196A mice had lower body weight and less visceral adipose tissue; this was associated with transcriptional reprograming of the adipose tissue macrophages and T cells, and resolution of inflammation resulting in less fat accumulation within adipocytes. Thus, reducing LXRα pS196 in hematopoietic cells attenuates atherosclerosis and obesity by reprogramming the transcriptional activity of LXRα in macrophages and T cells to promote an anti-inflammatory phenotype

    Reflection KK-matrices related to Temperley-Lieb RR-matrices

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    The general solutions of the reflection equation associated with Temperley-Lieb RR-matrices are constructed. Their parametrization is defined and the Hamiltonians of corresponding integrable spin systems are given.Comment: 11 pages, no figures. References added and a few misprints corrected. To appear in Theoretical and Mathematical Physics (2011

    Restauration morpho-dynamique et redynamisation de la section court-circuitée du Rhin en aval du barrage de Kembs (projet INTERREG / EDF)

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    National audienceThe Upper Rhine River has been heavily impacted by channelization for flood protection and navigation, and then by damming for hydropower generation. In normal non flooding conditions, most of the flows are diverted in a canalized section whereas the regulated “old Rhine” bypassed reach runs a minimum flow. Between Huningue and Neuf-Brisach, engineering works induced simplification and stabilization of the channel pattern from a formerly braiding sector to a single incised channel, hydrological modifications, bottom armouring due to bedload decrease, and thus ecological alterations. Two complementary and interdisciplinary projects have been initiated to restore alluvial morphodynamics: i) the international “INTERREG IV - Redynamisation of the old Rhine” project (2009-2012) coordinated by the Alsace region, France; ii) the left bank “controlled erosion” project launched by Electricité de France (EDF) within Kembs hydroelectric station relicensing process since 2003-2004. The purpose of these projects is to evaluate the feasibility of an important hydro-morphological and ecological restoration plan on a 45 km long reach, through both field testing of bank erosion techniques at favourable locations, and artificial sediments input from right bank excavations. This will help define possible long term prospective scenarios, in order to restore sustainable sediment transport, morphodynamics variability and associated ecological functions. The study will involve historical analysis, hydro-morphological / hydraulic physical and numerical modelling, physical and ecological monitoring, and sociological aspectsLe Rhin alsacien-allemand a enregistré de profondes modifications morphologiques et hydrologiques à la suite de sa correction et de sa régularisation pour la protection contre les crues et la navigation, puis après la construction de barrages hydro-électriques. Les aménagements réalisés entre Huningue et Neuf-Brisach ont engendré une simplification et une stabilisation du style fluvial. Un fleuve en tresses a cédé la place à un chenal unique incisé. Le fond de chenal est devenu pavé à cause d’une diminution des apports de charge de fond et des altérations écologiques ont été observées (simplification des habitats aquatiques et riverains). Deux projets complémentaires et interdisciplinaires ont été engagés afin de restaurer une dynamique des formes alluviales : i) le projet international INTERREG IV – Redynamisation du Vieux Rhin (2009-2012) sous l’impulsion de la région Alsace ; ii) le projet d’érosion maitrisée des berges de la rive gauche conduit par Electricité de France (EDF) dans le cadre du renouvellement de la concession de l’aménagement de Kembs. L’objectif des deux projets est de définir un plan de restauration hydro-morphologique et écologique conduisant à la redynamisation d’un tronçon de 45 km. L’étude repose sur une analyse historique, l’exploitation de modèles à la fois physiques et numériques, et les suivis morphologiques in situ d’une recharge artificielle en sédiments et d’érosions de berge contrôlées. Ces études de faisabilité sont complétées par des analyses écologique et sociologique pour apprécier l’impact socio-environnemental de ces projets
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