15,761 research outputs found

    Optical and Near Infrared Study of the Cepheus E outflow, a very low excitation object

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    We present images and spectra of the Cepheus E (Cep E) region at both optical and infrared wavelengths. Only the brightest region of the southern lobe of the Cep E outflow reveals optical emission, suggesting that the extinction close to the outflow source plays an important r\^ole in the observed difference between the optical and IR morphologies. Cep E is a unique object since it provides a link between the spectroscopic properties of the optical Herbig-Haro (HH) objects and those of deeply embedded outflows.Comment: Accepted Astron. J., 8 files: paper, tables plus 6 figure

    Persistence in the zero-temperature dynamics of the QQ-states Potts model on undirected-directed Barab\'asi-Albert networks and Erd\"os-R\'enyi random graphs

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    The zero-temperature Glauber dynamics is used to investigate the persistence probability P(t)P(t) in the Potts model with Q=3,4,5,7,9,12,24,64,128Q=3,4,5,7,9,12,24,64, 128, 256,512,1024,4096,16384256, 512, 1024,4096,16384 ,..., 2302^{30} states on {\it directed} and {\it undirected} Barab\'asi-Albert networks and Erd\"os-R\'enyi random graphs. In this model it is found that P(t)P(t) decays exponentially to zero in short times for {\it directed} and {\it undirected} Erd\"os-R\'enyi random graphs. For {\it directed} and {\it undirected} Barab\'asi-Albert networks, in contrast it decays exponentially to a constant value for long times, i.e, P(‚ąě)P(\infty) is different from zero for all QQ values (here studied) from Q=3,4,5,...,230Q=3,4,5,..., 2^{30}; this shows "blocking" for all these QQ values. Except that for Q=230Q=2^{30} in the {\it undirected} case P(t)P(t) tends exponentially to zero; this could be just a finite-size effect since in the other "blocking" cases you may have only a few unchanged spins.Comment: 14 pages, 8 figures for IJM

    Modular classes of Poisson-Nijenhuis Lie algebroids

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    The modular vector field of a Poisson-Nijenhuis Lie algebroid AA is defined and we prove that, in case of non-degeneracy, this vector field defines a hierarchy of bi-Hamiltonian AA-vector fields. This hierarchy covers an integrable hierarchy on the base manifold, which may not have a Poisson-Nijenhuis structure.Comment: To appear in Letters in Mathematical Physic

    A contabilidade p√ļblica em S√£o Tom√© e Pr√≠ncipe: situa√ß√£o atual e perspetivas futuras

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    Con este artigo es pretendido contribuir para el conocimiento sobre la situaci√≥n de la aplicaci√≥n del Sistema de Administraci√≥n Financiera del Estado ‚Äď SAFE en S√£o Tom√© y Pr√≠ncipe. En concreto, fue pretendido hacer una an√°lisis a lo sistema contable aplicable a las entidades p√ļblicas, a trav√©s de la identificaci√≥n de posibles deficiencias y/o debilidades del sistema, apuntando sugerencias de mejora del sistema. Para tal, se han procedido a realizaci√≥n de una investigaci√≥n a trav√©s de una an√°lisis cualitativa y entrevistas semi-estructuradas, dirigidas al personal de gesti√≥n y consultores que apoyan la aplicaci√≥n del SAFE. Los resultados mostraron que la aplicaci√≥n del SAFE ha llevado a una mejor gesti√≥n de las finanzas p√ļblicas en S√£o Tom√© y Pr√≠ncipe, donde los aspectos innovadores respectan sobre todo a la reforma de la Contabilidad P√ļblica. Sin embargo, el actual sistema de contabilidad parece denotar ciertas limitaciones, debido a la falta de regulaci√≥n de algunos aspectos del SAFE, como, por ejemplo, la falta de definici√≥n/aclaraci√≥n de ciertos t√©rminos que ha permitido diferentes interpretaciones

    Adubação nitrogenada e posição de amostragem em sistema silvipastoril.

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    Resumo: O experimento foi desenvolvido para avaliar a produtividade e a morfologia da Brachiaria brizantha cv. Marandu adubada com ur√©ia e sulfato de am√īnio e em fun√ß√£o da posi√ß√£o de amostragem. Foi adotado o esquema de parcelas subdivididas no espa√ßo, sendo a parcela principal constitu√≠da por fonte de adubo nitrogenado e a subparcela constitu√≠da pela posi√ß√£o de amostragem da braqui√°ria no sub-bosque do sistema silvipastoril no delineamento em blocos casualizados com seis repeti√ß√Ķes. A aduba√ß√£o nitrogenada e a posi√ß√£o de amostragem podem influenciar a produtividade e a rela√ß√£o F/C da braqui√°ria em sistema silvipastoril. [Nitrogen fertilization and position sampling in silvopastoral system]. Abstract: The experiment was carried to evaluate the yield and morphology of Brachiaria brizantha cv. Marandu fertilized with urea and ammonium sulfate, and depending on the sampling position. A split plot arrangement, with six replicates in the randomized block design, was utilized. The main plot consists of a source of nitrogen fertilizer and sub-plots sampling position of pasture in understory of silvopastoral system. Nitrogen fertilization and sampling position can influence productivity and leaf lamina:stem ratio of Brachiaria in silvopastoral system

    Comparison of 30 THz impulsive burst time development to microwaves, H-alpha, EUV, and GOES soft X-rays

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    The recent discovery of impulsive solar burst emission in the 30 THz band is raising new interpretation challenges. One event associated with a GOES M2 class flare has been observed simultaneously in microwaves, H-alpha, EUV, and soft X-ray bands. Although these new observations confirm some features found in the two prior known events, they exhibit time profile structure discrepancies between 30 THz, microwaves, and hard X-rays (as inferred from the Neupert effect). These results suggest a more complex relationship between 30 THz emission and radiation produced at other wavelength ranges. The multiple frequency emissions in the impulsive phase are likely to be produced at a common flaring site lower in the chromosphere. The 30 THz burst emission may be either part of a nonthermal radiation mechanism or due to the rapid thermal response to a beam of high-energy particles bombarding the dense solar atmosphere.Comment: accepted to Astronomy and Astrophysic

    Redesenho de agroecossistemas como inovação social para a construção da sustentabilidade local.

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    Resumo: A constru√ß√£o de uma nova perspectiva para o semi√°rido rural nordestino dever√° estar amparada em abordagens com enfoque multidisciplinar, em que o contexto seja a refer√™ncia e que promova o rompimento com o padr√£o convencional da moderniza√ß√£o agr√≠cola. Este estudo objetivou demonstrar aportes metodol√≥gicos de abordagem no meio rural, com a finalidade de construir elementos de resist√™ncia ao modelo tradicional por meio da media√ß√£o social para o redesenho de agroecossistemas. A metodologia foi orientada pela abordagem te√≥rica da Perspectiva Orientada aos Atores. A pesquisa foi desenvolvida na comunidade S√≠tio Areias, Sobral, CE, local onde foi realizado o redesenho de um agroecossistema. A utiliza√ß√£o da metodologia possibilitou a interface entre saberes, com o surgimento de novas pr√°ticas, com os agricultores familiares exercendo sua condi√ß√£o de ag√™ncia na utiliza√ß√£o de novos dom√≠nios para a produ√ß√£o de novidades referentes √† constru√ß√£o de uma agricultura sustent√°vel no semi√°rido. Tais inova√ß√Ķes sociais poder√£o constituir elementos basilares para um novo processo de desenvolvimento rural sustent√°vel e solid√°rio, com novas formas de inova√ß√Ķes no meio rural. Abstract: Building a new perspective to the rural northeastern semiarid should be supported by approaches with a multidisciplinary focus, that has the context as a reference and promotes rupture with the conventional pattern of agricultural modernization. This study aimed to demonstrate methodological contributions of approach in rural areas, with the aim of constructing elements of resistance to the traditional model through social mediation for the redesign of agroecosystems. The methodology was guided by the theoretical approach of the Oriented Perspective by Actors. The research was conducted in the community S√≠tio Areias, Sobral, CE, where was conducted the redesign of one agroecosystem. Using the methodology enabled the interface between knowledges, with the emergence of new practices, with family farmers exerting their agency conditions on the use of new domains for the novelty production relative the construction of sustainable agriculture in semiarid. These social innovations may constitute basic elements for a new process of sustainable rural development and solidarity, with new forms of innovation in rural areas

    Efeito do lodo de esgoto nos fluxos de gases na interface solo-atmosfera.

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    O objetivo do presente trabalho foi estudar o efeito da aplica√ß√£o a longo prazo e continuada de lodo de esgoto da Esta√ß√£o de Tratamento de Esgoto de Barueri, SP, no fluxo de gases na interface soloatmosfera sob condi√ß√Ķes de campo e em condi√ß√Ķes tropicais.bitstream/CNPMA/5827/1/comunicado_32.pd
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