Avaliação econômica de pastagens: método da taxa interna de retorno com uso de microcomputador.

As baixas qualidade e disponibilidade das pastagens, especialmente na estação seca, têm sido apontadas como as principais causas do baixo desfrute do rebanho brasileiro. Na tentativa de encontrar soluções para este problema, pesquisadores, extensionistas e produtores têm intensificado esforços na busca de gramíneas exóticas, bem como estratégias alternativas para formação e conservação de pastagem cultivada, para oferecer melhor alimentação para os rebanhos a custos mais baixos. Entretanto, um aspecto que deve ser levado em conta na busca da pastagem mais adequada é a multiplicidade de condições em cada fazenda. Diferentes categorias animais e condições de clima, solo, vegetação nativa e infraestrutura regional, determinam as espécies forrageiras e os sistemas de formação e conservação de pastagem mais adequados economicamente. Dentre os métodos de formação e conservação de pastagens, há um grande número de alternativas. O método de abertura da mata, mecânico ou manual, o aproveitamento Inicial da área, com lavoura ou capim. a intensidade de uso e conservação da pastagem. a freqüência de rocadas e adubação constituem decisões determinantes de custos e benefício das pastagens.bitstream/item/131376/1/avaliacao-economica-de-pastagens.pd

U-Pb Studies of Zircon Cores and Overgrowths, and Monazite: Implications for Age and Petrogenesis of the Northeastern Idaho Batholith

U/Pb isotopic studies of zircons, many containing xenocrystic cores with euhedral overgrowths, and monazite from igneous rocks and metasedimentary inclusions of the northeastern Idaho batholith yield linear arrays on concordia diagrams. We interpret these as mixing lines between an old component (cores) and a young component (overgrowths and zircons without cores). The lower intercept of such arrays with concordia may yield the minimum age of the rocks if the overgrowths and zircons without cores are discordant, or the crystallization age if they are concordant. Monazites yield apparently concordant ages either equal or less than the lower intercept zircon ages. The samples studied yield lower intercept ages ranging from 73.5+ or -6 Ma (foliated quartz diorite) to 46.5+ or -1 Ma (feldspar megacryst granite); ages obtained are consistent with crosscutting relations observed in the field. Upper intercepts yield ages of 1700 to 2349 Ma. These are interpreted to indicate the mean age of xenocrystic zircon. Studies of zircons from xenolith suites indicate that they could represent the source of the old zircon component. The zircon and monazite results, the generally high initial 87Sr/86Sr ratios of the igneous rocks, and the isotopic composition of Pb in feldspar indicate that the magmas were derived anatectically from a continental crustal source or were extensively mixed with such old crust prior to or during emplacement

Fano resonances in plasmonic core-shell particles and the Purcell effect

Despite a long history, light scattering by particles with size comparable with the light wavelength still unveils surprising optical phenomena, and many of them are related to the Fano effect. Originally described in the context of atomic physics, the Fano resonance in light scattering arises from the interference between a narrow subradiant mode and a spectrally broad radiation line. Here, we present an overview of Fano resonances in coated spherical scatterers within the framework of the Lorenz-Mie theory. We briefly introduce the concept of conventional and unconventional Fano resonances in light scattering. These resonances are associated with the interference between electromagnetic modes excited in the particle with different or the same multipole moment, respectively. In addition, we investigate the modification of the spontaneous-emission rate of an optical emitter at the presence of a plasmonic nanoshell. This modification of decay rate due to electromagnetic environment is referred to as the Purcell effect. We analytically show that the Purcell factor related to a dipole emitter oriented orthogonal or tangential to the spherical surface can exhibit Fano or Lorentzian line shapes in the near field, respectively.Comment: 28 pages, 10 figures; invited book chapter to appear in "Fano Resonances in Optics and Microwaves: Physics and Application", Springer Series in Optical Sciences (2018), edited by E. O. Kamenetskii, A. Sadreev, and A. Miroshnichenk

Época de aplicação e tipos de dessecantes na qualidade fisiológica de sementes de soja.

Objetivou-se neste trabalho avaliar o efeito de dessecantes aplicados em diferentes épocas, na qualidade fisiológica e no vigor de sementes de soja da cultivar BRS 247 RR

Teste alternativo para avaliação do potencial fisiológico de sementes de milho e feijão de porco.

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Phenolic compounds and organic acids evaluation on red grapes used for winemaking in the Northeast of Brazil.

Monitoring maturation to determine harvest time is very important to determine the enological potential and the quality characteristics and typicality of the wines (Borghezan et al., 2011). Considering that there is no cold weather in the São Francisco Valley, it is possible to scale and production of two harvests per year. This study aimed to determine the chemical composition of the ?Syrah? and ?Tempranillo? grapes, during maturation. Sixty plants were used for each cultivar, divided into three blocks

Chemistry composition during red grapes maturation for wines elaboration in Northeast Brazil.

This study aimed to determine physical characteristics and chemical composition of grapes cvs. Syrah and Tempranillo, during maturatio

Chemistry composition during red grapes maturation for wines elaboration in Northeast Brazil.

This study aimed to determine physical characteristics and chemical composition of grapes cvs. Syrah and Tempranillo, during maturatio

The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200