683 research outputs found

    On the classification and properties of noncommutative duplicates

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    We give an explicit description of the set of all factorization structures, or twisting maps, existing between the algebras k^2 and k^2, and classify the resulting algebras up to isomorphism. In the process we relate several different approaches formerly taken to deal with this problem, filling a gap that appeared in a recent paper by Cibils. We also provide a counterexample to a result concerning the Hochschild (co)homology appeared in a paper by J.A. Guccione and J.J. Guccione.Comment: 11 pages, no figure

    Natural and projectively equivariant quantizations by means of Cartan Connections

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    The existence of a natural and projectively equivariant quantization in the sense of Lecomte [20] was proved recently by M. Bordemann [4], using the framework of Thomas-Whitehead connections. We give a new proof of existence using the notion of Cartan projective connections and we obtain an explicit formula in terms of these connections. Our method yields the existence of a projectively equivariant quantization if and only if an \sl(m+1,\R)-equivariant quantization exists in the flat situation in the sense of [18], thus solving one of the problems left open by M. Bordemann.Comment: 13 page

    Contribución al conocimiento de Porosagrotis gypaetina (Guen.) (Lep.:Noctuidae)

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    p.15-22Este trabajo tiene por finalidad brindar una descripcion detallada de los diferentes estados de desarrollo, asi como de los estadios larvales, de Porosagrotis gypaetina (Guen.) y estimar sus principales parametros biologicos. Se trata de una oruga conocida vulgarmente como gusano pardo que frecuenta cultivos de alfalfa, trebol bianco, maiz y girasol y determinadas malezas. Los caracteres considerados para su identificacion fueron, en el huevo: numero y distribucion de costas; en la larva: pigmentacion, distribucion de manchas y cerdas corporales; en la pupa: tamaño, forma y color y caracteristicas del cremaster; y en el adulto: ubicacion y coloracion de maculas y nervaduras alares. La emergencia de imagos alcanzo su maximo en abril y mayo. El periodo embrionario se completo en 22 a 26 dias. Aproximadamente la mitad de las larvas cumplieron su ciclo en 6 estadios y las restantes en 7; la duracion total del periodo larval fue de 134 a 141 dias, sin considerar la forma prepupal e independientemente del numero de estadios. Las orugas permanecieron como prepupas durante la temporada estival (aproximadamente 161 dias). El estado pupal duro 40 a 57 dias. Las observaciones realizadas permiten expresar que, inediante los caracteres descriptos, es factible reconocer la especie a traves no solo de los adultos, sino de sus estados inmaduros. Posee una sola generacion anual; transcurre el inviemo como larva; el daño tipico de corte lo produce a partir del cuarto estadio larval

    A CORRELATED STUDY OF THE RESPONSE OF A SATELLITE TO ACOUSTIC RADIATION USING STATISTICAL ENERGY ANALYSIS AND ACOUSTIC TEST DATA*

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    Statistical Energy Analysis (SEA) is an accepted technique for computational modeling of high flequency structural response under vibroacoustic excitation. An SEA study was recently completed for a small satellite project for which Sandia National Laboratories is the system integrator. Since response data were available from an acoustic test of the satellite, we were able to both refine the model and judge the accuracy of the final "best effort" prediction

    (In)Sufficiency of industrial decarbonization to reduce household carbon footprints to 1.5°C-compatible levels

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    Scenarios that limit global warming to 1.5°C rely on a combination of interventions to reduce greenhouse gas emissions and capture carbon dioxide. However, the extent to which lifestyle change contributes to mitigation relative to technological change over time remains understudied. Here, we present a scenario model that incorporates extensive supply-side technological transformations while excluding lifestyle changes. By adapting a global supply-use table from EXIOBASE using elements from Shared Socioeconomic Pathway 1 and a mitigation pathway consistent with the 1.5°C target, we assess how household footprints evolve in 2030 and 2050 and the extent to which technological change alone can mitigate greenhouse gas emissions. We modeled footprints for 49 countries/regions, with a focus on the EU27. Our scenario results indicate that while technological change can substantially reduce emissions, the reductions are ultimately insufficient to achieve the 1.5°C target. Eight EXIOBASE regions, including three EU27 countries, are on a 1.5°C-consistent trajectory with just technological advancements in 2030. However, by 2050, no countries are projected to meet the 1.5°C-compatible target. The average EU27 overshoot for household footprints approaches 2.2 tCO2e/cap in 2030 and 3.1 tCO2e/cap in 2050. Global overshoots are more moderate at 0.3 tCO2e/cap in 2030 and 2.0 tCO2e/cap in 2050. Our results highlight the critical role of household lifestyle transformation in climate change mitigation. Future research can explore the diverse lifestyle change pathways necessary to align with the aspirational 1.5°C target outlined in the Paris Agreement.Horizon 2020(H2020)101003880Industrial Ecolog

    The promise of the affordable artist's studio: Governing creative spaces in London

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    The role of artists' organisations in populating and popularising postindustrial urban areas is well documented. However, what are less apparent are analyses of how spaces of artistic production are organised and governed in these areas. This paper explores, via an analysis of organisational documents and practices, the techniques used by London-based affordable studio providers to imagine, calculate, and make material low-cost workspace for artists. The argument made is that the negotiation of competing agendas around the production of cultural, economic, and social benefit by affordable studio providers has led to the emergence of a specific form of affordable studio. This analysis will thus show how configurations of creative space emerge from mundane techniques of measurement and governance. © 2013 Pion and its Licensors

    Freeze-out configuration properties in the 197Au + 197Au reaction at 23 AMeV

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    Data from the experiment on the 197Au + 197Au reaction at 23 AMeV are analyzed with an aim to find signatures of exotic nuclear configurations such as toroid-shaped objects. The experimental data are compared with predictions of the ETNA code dedicated to look for such configurations and with the QMD model. A novel criterion of selecting events possibly resulting from the formation of exotic freeze-out configurations, "the efficiency factor", is tested. Comparison between experimental data and model predictions may indicate for the formation of flat/toroidal nuclear systems
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