26,830 research outputs found

    BRST quantization of quasi-symplectic manifolds and beyond

    Full text link
    We consider a class of \textit{factorizable} Poisson brackets which includes almost all reasonable Poisson structures. A particular case of the factorizable brackets are those associated with symplectic Lie algebroids. The BRST theory is applied to describe the geometry underlying these brackets as well as to develop a deformation quantization procedure in this particular case. This can be viewed as an extension of the Fedosov deformation quantization to a wide class of \textit{irregular} Poisson structures. In a more general case, the factorizable Poisson brackets are shown to be closely connected with the notion of nn-algebroid. A simple description is suggested for the geometry underlying the factorizable Poisson brackets basing on construction of an odd Poisson algebra bundle equipped with an abelian connection. It is shown that the zero-curvature condition for this connection generates all the structure relations for the nn-algebroid as well as a generalization of the Yang-Baxter equation for the symplectic structure.Comment: Journal version, references and comments added, style improve

    Efeito de pesticidas aos polinizadores do guaranazeiro: avaliação da toxicidade aguda de inseticidas às abelhas (Hymenoptera: Apidae).

    Get PDF
    Neste trabalho foi avaliada a sensibilidade da espécie de abelha Melipona seminigra, nativa da Amazônia, ao inseticida Parathion metil

    The role of digital technologies in the innovation of collaborative networks: The case of the ornamental stones in Portugal

    Get PDF
    This exploratory research outlines an innovative business model for the ornamental stones, in Portugal, targeting World Class Manufacturing. Research questions arise from an inductive approach empirically based on a participant-observer that participated in JETSTONE and INOVSTONE, two important Mobilising Projects for the cluster. A collaborative network pursuing a Service Systems view, leveraged by digital technologies was proposed based on a 3-stage development facilitated by the ARCON framework (ECOLEAD project), as follows: development of a general VBE/VO model completed by knowledge coming from BIM, Industry 4.0, IoT and Service Science backgrounds, in order to build up a specific model to the ornamental stones Industry. Finally, the specific model should be verified by case studies as demonstrating instances. While the generic VBE/VO might be customized to other domains, the specific model generates a representation of the Industry and the case studies serve as instances to verify it.info:eu-repo/semantics/publishedVersio

    Evapotranspiração de um pomar de mangueiras irrigadas na região do Submédio São Franscisco.

    Get PDF
    O presente trabalho objetivou determinar aevapotranspiração durante o ciclo produtivo da mangueira,variedade ?Tommy Atknis`, cultivada nas condições declima e solo da região do Submédio São Francisco

    Developing a research agenda for digital accessibility in multinational enterprises

    Get PDF
    Digital accessibility for disabled people is a hot topic of Corporate Social Responsibility, mandatory under current UN and UE dispositions. This research aims at investigating its company-wide administrative integration by developing a systematic process of enquiry producing a diagnosis tool under the guidance of the Soft Systems Methodology (RQ3). Absorptive capacity provided the theoretical umbrella for structuring the problem-situation (RQ1) by setting its Root Definitions. Thus, the expected scientifically supported diagnosing tool should generate feasible and desirable changes to the problem-situation perceptions (RQ2). Digital Accessibility by Design in Service was coined to define this innovative and relevant approach.info:eu-repo/semantics/acceptedVersio

    Avaliação agronômica de genótipos de feijão-caupi para feijão-verde.

    Get PDF
    O trabalho objetivou avaliar e selecionar genótipos de feijão-caupi para a produção de feijão-verde. O ensaio foi conduzido no período de julho a outubro de 2011 no campo experimental da Embrapa Meio-Norte, em Teresina, PI. Utilizou-se o delineamento em blocos casualizados, com 14 tratamentos e quatro repetições. Os caracteres avaliados foram: número de dias para o início da floração (NDIF), reação a vírus (RV), comprimento de vagens verdes (COMPVV), número de grãos por vagens verdes (NGVV), peso de cem grãos verdes (P100GV), produtividade de vagens verdes (PVV), produtividade de grãos verdes (PGV) e índice de grãos verdes (IGV). Foram realizadas análises de variância e comparação de médias. Dentre os genótipos avaliados observou-se que o MNC05-835B-16 apresenta-se como possível fonte de resistência a vírus. As linhagens MNC-303-09E, MNC00-595F-2, MNC00-595F-27, MNC05-835B-16, MNC05-847B-126, Sempre-Verde e Paulistinha constituem uma alternativa para o melhoramento visando aumentar o tamanho da vagem e o número de grãos por vagem verde. A seleção para a produtividade de grãos verdes não é indicada para o grupo de linhagens avaliado. A cultivar Sempre-Verde destacou-se das demais por apresentar boas médias para a PVV, PGV e IGV
    corecore