6,154 research outputs found

    Complexified sigma model and duality

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    We show that the equations of motion associated with a complexified sigma-model action do not admit manifest dual SO(n,n) symmetry. In the process we discover new type of numbers which we called `complexoids' in order to emphasize their close relation with both complex numbers and matroids. It turns out that the complexoids allow to consider the analogue of the complexified sigma-model action but with (1+1)-worldsheet metric, instead of Euclidean-worldsheet metric. Our observations can be useful for further developments of complexified quantum mechanics.Comment: 15 pages, Latex, improved versio

    A novel protocol for the one-pot borylation/Suzuki reaction provides easy access to hinge-binding groups for kinase inhibitors

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    The one-pot borylation/Suzuki reaction is a very efficient means of accessing cross-coupling products of two aryl-halide partners that generally requires the use of specific catalysts or ligands and/or relatively long reaction times. This new microwave-assisted method provides a quick one-pot borylation/Suzuki reaction protocol that we applied to the synthesis of various bi- or poly-aryl scaffolds, including a variety of aryl and heteroaryl ring systems and the core frameworks of kinase inhibitors vemurafenib and GDC-0879

    A shadowgraph study of two proposed Shuttle-C launch vehicle configurations

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    A shadowgraph study concerning two of the proposed Shuttle-C launch vehicle configurations are presented. These shadowgraphs were obtained from a wind tunnel test performed in Marshall Space Flight Center's 14-in trisonic wind tunnel at various angles-of-attack and roll angles over the Mach range of 0.6 to 4.96. Variations in payload bay length were also evaluated. Major flow field phenomena can easily be seen in the shadowgraphs. Shadowgraphs are a valuable resource. They are used in the analysis of the external flow conditions the launch vehicle encounters through the ascent stage of flight. Subsequent reports will contain shadowgraph studies for other launch vehicle configurations also tested in the Marshall Space Flight Center's 14-in trisonic wind tunnel

    Aerodynamic characteristics of the National Launch System (NLS) 1 1/2 stage launch vehicle

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    The National Aeronautics and Space Administration (NASA) is studying ways of assuring more reliable and cost effective means to space. One launch system studied was the NLS which included the l l/2 stage vehicle. This document encompasses the aerodynamic characteristics of the 1 l/2 stage vehicle. To support the detailed configuration definition two wind tunnel tests were conducted in the NASA Marshall Space Flight Center's 14x14-Inch Trisonic Wind Tunnel during 1992. The tests were a static stability and a pressure test, each utilizing 0.004 scale models. The static stability test resulted in the forces and moments acting on the vehicle. The aerodynamics for the reference configuration with and without feedlines and an evaluation of three proposed engine shroud configurations were also determined. The pressure test resulted in pressure distributions over the reference vehicle with and without feedlines including the reference engine shrouds. These pressure distributions were integrated and balanced to the static stability coefficients resulting in distributed aerodynamic loads on the vehicle. The wind tunnel tests covered a Mach range of 0.60 to 4.96. These ascent flight aerodynamic characteristics provide the basis for trajectory and performance analysis, loads determination, and guidance and control evaluation

    Fashion micro-enterprises in London, Berlin, Milan

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    This report provides an account of a series of interviews, observational visits and hosted events with 8-10 fashion designers in three cities: London, Berlin and Milan, carried out from 2012-2016. In some cases we interviewed the same designers two or three times over a period of nearly three years. The research project also entailed documented conversations and meetings with a range of fashion experts, consultants, legal advisors and policy makers in each city. Often these took place within the context of organised events undertaken as part of the research process. The aim was to investigate the kind of start-ups or micro-enterprises which have come into being in the last decade. We were interested in whether these were the outcome of pro-active urban creative economy policies or if they were self-organised initiatives, a reaction to the crisis of the euro-zone of 2008 and the consequent recession. Was it the case that long-term austerity policies and exceptionally high rates of youth and graduate unemployment across Europe had spawned these kinds of seemingly independent economic activities? We were also minded to consider the role of intellectual property (IP) and copyright in fashion as part of the wider UK government agenda for growth and wealth creation within the creative economy as a whole

    Systematic Review – Final: Have arid land springs restoration projects been effective in restoring hydrology, geomorphology, and invertebrates and plant species composition comparable to natural springs with minimal anthropogenic disturbance?

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    The aim of this review is to examine the effectiveness of springs restoration projects in the southwestern United States in restoring hydrology, geomorphology, and plant and invertebrates species composition to condiitions comparable with natural springs with minimal anthropogenic disturbances
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