17,899 research outputs found

    Cost, power consumption and performance analysis in SDM ROADM architectures for uncoupled spatial channels

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    Currently optical networks are reaching their maximum transport capacity. Different solutions can be used to overcome this capacity limit, but we are going to study, in particular, space division multiplexing (SDM). To use SDM, the reconfigurable optical add/drop multiplexers (ROADMs) need to be adapted to support this multiplexing. In this paper we analyze four switching strategies used in SDM ROADMs and the respective SDM ROADM architectures. These strategies are explained and analyzed, for uncoupled scenarios, in terms of cost and power consumption. The impact of the physical layer impairments (PLIs) amplified spontaneous emission noise, non-linear interference, passband narrowing due to optical filtering and in-band crosstalk is also assessed, considering a cascade of SDM ROADMs with spatial and spatial-wavelength switching granularities. The PLI inband crosstalk, has insignificant impact, in networks with a single spatial channel or in SDM networks with spatial granularity ROADM architecture, but in a SDM network with spatial wavelength granularity this PLI can lead to an OSNR penalty of around 2 dB, when the number of spatial channels is high. The other PLIs have similar impacts in all networks studied.info:eu-repo/semantics/acceptedVersio

    On zooplankton of the coastal waters of Rio Grande Do Norte sampled from oil producing platform

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    Lack of a comprehensive knowledge of zooplankton of the coastal waters of the northeast region of Brazil prompted the present study. Seasonal and diurnal collections were made from an oil producing platform located off Ouamari, Rio Grande do Norte, %azi! during the period of one year from March 1987 to February 1988. A pneliminary analysis of the samples showed a discernible seasonal fluctu* atioD and a clear pattern of diurnal changes in the composition of zooplankton

    Desempenho produtivo da braquiaria, em cultivo solteiro e consorciado com milho, em resposta à irrigação.

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    Um dos fatores que definem a expressão do potencial produtivo das culturas é o adequado suprimento hídrico. O presente trabalho teve como objetivo avaliar quatro níveis de irrigação (L1 –564,5; L2 – 583,7; L3 – 607,3 e L4 – 647,9 mm) sob a produtividade de massa verde e seca da Brachiaria ruziziensis em cultivo solteiro e consorciado com o milho. O experimento foi conduzido no Campo Experimental da Embrapa Meio-Norte, no Município de Alvorada do Gurguéia – PI, no período de julho a novembro de 2009. Para a aplicação das lâminas de irrigação, usou-se um sistema de irrigação por aspersão convencional fixo. Em ambos os sistemas de cultivo, a braquiaria foi semeada quando o milho apresentava quatro folhas definitivas, em um espaçamento de 0,45 m entre fileiras, em cultivo solteiro, e nas entrelinhas do milho, no sistema consorciado. O milho híbrido (BRS 1030) foi semeado em um espaçamento de 0,90 m entre fileiras. Em cultivo solteiro, a máxima produtividade de massa verde (62,9 t/ha) e seca (18,6 t/ha) foi obtida com as lâminas de 605,4 mm e 614,2 mm, respectivamente. Em consórcio com o milho, a máxima produtividade de massa verde (12,2 t/ha) e seca (4,2 t/ha) foi obtida com as lâminas de 600,3 mm e 601,2mm, respectivamente

    Selection index via REML/BLUP for identifying superior banana genotypes in the central region of Goiás state, Brazil.

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    EN-US: This study had the aim of evaluating 15 agronomic characters of 23 banana genotypes of the Cavendish, Prata, Prata-Anã, Pacovan, Mysore and Maçã groups, in three production cycles, in the climatic conditions of the central region of Goiás state, Brazil, identifying superior cultivars. The treatments were arranged in a completely randomized design, with replicates varying from 3 to 18 clones according to the availability of seedlings. Because of the unbalanced data, the components of variance were estimated using the mixed model methodology. In order to identify the superior genotypes, the predicted mean genotypic values were taken into account. The FHIA-02 (Cavendish group), PA42-44 (Prata Anã group) and FHIA-18 (Prata Anã group) genotypes presented the highest flowering precocity. The Bucanero, FHIA-17 (Cavendish group) and Grande Naine genotypes were the most productive. The Grande Naine, FHIA-17 and FHIA-02 genotypes presented the lowest sizes, and the FHIA-17, Bucanero and PV79-34 (Hybrid Pacovan) genotypes the largest pseudo stems circumferences. The genotypes with the lowest mortality rates were the Pacovan, Garantida (group Prata) and Calipso. Based on the multi-trait selection index, it was concluded that the FHIA-17, Grande Naine, Bucanero, and FHIA-02 genotypes were the most promising cultivars for production in the central region of Goiás due to their agronomic characters and high yield. | PT-BR: Este trabalho teve como objetivo avaliar 15 caracteres agronômicos de 23 genótipos de bananeira dos grupos Cavendish, Prata, Prata-Anã, Pacovan, Mysore e Maçã, em três ciclos de produção, nas condições climáticas da região central de Goiás, Brasil, a fim de identificar os melhores cultivares para essa região. Os tratamentos foram dispostos em delineamento inteiramente casualizado, com repetições variando de 3 a 18 clones de acordo com a disponibilidade de mudas. Por se tratar de dados desbalanceados os componentes de variância foram estimados utilizando a metodologia de modelos mistos. Com o intuito de identificar os genótipos superiores foi levado em consideração os valores genotípicos médios preditos. Os genótipos FHIA-02 (grupo Cavendish), PA42-44 (grupo Prata Anã) e FHIA-18 (grupo Prata Anã), apresentaram maior precocidade de floração. Os genótipos Bucanero, FHIA-17 (grupo Cavendish) e Grande Naine foram os mais produtivos. Os genótipos Grande Naine, FHIA-17 e FHIA-02 apresentam os menores portes e os genótipos FHIA-17, Bucanero e PV79-34 (híbrido de Pacovan) as maiores circunferências do pseudocaule. Os genótipos com as menores taxas de mortalidade foram Pacovan, Garantida (grupo Prata) e Calipso. Com base no índice de seleção, conclui-se que os genótipos FHIA-17, Grande Naine, Bucanero e FHIA-02 foram os mais promissores para serem produzidos na região central de Goiás, por apresentarem alta produtividade e caracteres agronômicos demandados pelos produtores

    Nambu monopoles in lattice Electroweak theory

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    We considered the lattice electroweak theory at realistic values of α\alpha and θW\theta_W and for large values of the Higgs mass. We investigated numerically the properties of topological objects that are identified with quantum Nambu monopoles. We have found that the action density near the Nambu monopole worldlines exceeds the density averaged over the lattice in the physical region of the phase diagram. Moreover, their percolation probability is found to be an order parameter for the transition between the symmetric and the broken phases. Therefore, these monopoles indeed appear as real physical objects. However, we have found that their density on the lattice increases with increasing ultraviolet cutoff. Thus we conclude, that the conventional lattice electroweak theory is not able to predict the density of Nambu monopoles. This means that the description of Nambu monopole physics based on the lattice Weinberg - Salam model with finite ultraviolet cutoff is incomplete. We expect that the correct description may be obtained only within the lattice theory that involves the description of TeV - scale physics.Comment: LATE
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