Büchwald-Hartwig reaction applied to synthesis of new luminescent liquid crystal triarylamines derived from isoxazoles

© 2015 Taylor & Francis Group, LLC. The present work describes the synthesis and characterization of novel series of triarylamines isoxazoles (TAA) addressed to the organic photovoltaic materials. Diarylisoxazoles were synthesized by sequential [3+2] 1,3-dipolar cycloaddition reaction between arylnitrile oxides and selected arylalkenes followed by MnO2-oxidation. Isoxazoles were coupled to diarylamines by Büchwald-Hartwig reaction to afford desired compounds 6a-k. Some TAA display liquid-crystalline behaviour and UV-Vis absorption and fluorescence emission were analysed for all samples of TAA 6a-k

Biomassa microbiana, carbono e nitrogênio do solo em pastagem nativa no Pantanal: efeito da queima.

Este estudo foi conduzido em área de pastagem nativa dominada por "capim carona", Elionurus muticus (Spreng.). Kuntze, no Pantanal, visando avaliar o efeito da queima sobre os conteúdos de C e N do solo.bitstream/CPAP/55785/1/BP73.pdfFormato Eletrônico

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

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

Estoques de carbono do estrato arbóreo de cerrados no Pantanal da Nhecolândia.

O objetivo deste trabalho foi estimar a biomassa aérea e o estoque de carbono do estrato arbóreo em duas áreas (um cerrado e um cerradão), localizadas no Pantanal da Nhecolândia, realizadas a partir de fórmula proposta por Brown et al. (1989) para florestas tropicais.bitstream/CPAP-2009-09/56774/1/COT68.pdfFormato eletrônico

Produtividade de braquiarias na sub-regiao da Nhecolandia, Pantanal, MS - Brasil.

O Pantanal, essa imensa planicie sedimentar, de aproximadamente 140.000 km2, possui como um dos pilares da economia a exploracao da bovinocultura de corte. O regime de criacao e do tipo extensivo, concentrada principalmente na atividade de cria. Dentre as sub-regioes do Pantanal, a Nhecolandia e uma das maiores em termos de area e onde esta concentrado o maior rebanho bovino. Os solos sao essencialmente arenosos, apresentando a vegetacao natural em quatro unidades geomorficas: "cerradao ou mata", "caronal, predominacia do capim carona - Elyonurus muticus, "campo-cerrado" e "vazante", essas divisoes sao determinadas pelo nivel de fertilidade do solo, nivel e duracao das enchentes. A precipitacao pluvial anual esta em torno de 1.000 a 1.400 mm. A alimentacao do rebanho bovino baseava-se exclusivamente em pastagem nativa. Entretanto, como alternativa para o aumento da produtividade, ha cerca de duas decadas vem sendo efetuada a formacao de pastagens, com a introducao de gramineas exoticas, inicialmente em areas de cerradao e cerrado e mais recentemente em campo de caronal, visando aumentar a oferta alimentar aos animais em epocas criticas. Destaca-se basicamente a introducao de Brachiarias decumbens e B. humidicola.bitstream/item/41118/1/PA17.pd

Carbon and nitrogen stocks in soil under different landscape units at the Pantanal ecosystem, Mato Grosso do Sul, Brazil.

This study aimed to evaluate the soil carbon and nitrogen storage under different landscape units in the Pantanal ecosystem.(Embrapa Gado de Corte. Documentos, 216). Coordenador Roberto Giolo de Almeida. II SIGEE. Disponível em: . Acesso em: 30 nov. 2016

High coercivity induced by mechanical milling in cobalt ferrite powders

In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500oC. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The XPD analysis by the Williamson-Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples

Modular classes of Poisson-Nijenhuis Lie algebroids

The modular vector field of a Poisson-Nijenhuis Lie algebroid $A$ is defined and we prove that, in case of non-degeneracy, this vector field defines a hierarchy of bi-Hamiltonian $A$-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