2,268 research outputs found
Características das espécies vegetais dispersas por aves e morcegos e suas implicações na recuperação ou manutenção de ambientes florestais.
Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Primary familial congenital erythrocytosis: two novel EPOR mutations found in Spain
Two-carbon ring expansions of vinyl β-lactones, were carried out by Lewis acids (BF3-Et2O or Et2AlCl) via an ionization/cation rearrangement. β,γ-unsaturated δ-lactones were produced as efficient protocols for the synthesis of bioactive substances.
Vinyl β-lactones were prepared via ring closure of corresponding unsaturated β-hydroxy acids. Differently structured substrates were examined to study the influence of the substituents on the rearrangement. Other factors, such as temperature, solvent and catalyst were also studied in search of suitable reaction conditions.
This method is moderately successful in providing fused-ring δ-lactones, but higher yields (so far total yield of 24.8%) and a better method for the separation of β- and δ-lactones are required for useful synthetic applications.
The successful implementation of this conceptually novel strategy will provide a versatile and expedient route for the synthesis of δ-lactones bearing a wide range of substitution patterns
Mutirões de trabalho em agroflorestas agroecológicas: variações e padrões nas atividades e práticas.
Charge delocalization and hyperpolarizability in ionic liquids
In this work the role that charge delocalization plays in the non-linear
optical response of ionic liquids is evaluated. The first hyperpolarizability
for the non-linear process of second harmonic generation (SHG) and second
hyperpolarizability for the non-linear process of electro-optical Kerr-Effect
(EOKE) of a large number of ionic liquid forming ions were estimated by means
of density functional theory calculations. The results point to that both
charge delocalization and molecular geometry are the key features that govern
their hyperpolarizabilities. Our findings show that some of the most commonly
used anions in ionic liquids are expected to present strong non-linear
responses while common cations present a much more limited performance.
However, this limitation can be overcome by a proper tailoring of cations to
present charge delocalization over large molecular regions. The hypothesis of
additivity of hyperpolarizabilities in ionic liquids is tested and exploited to
obtain a map of second and third order non-linear susceptibilities of 1496 ion
combinations. This map is intended to be a guide for future works on the
hyperpolarizability of ILsComment: 12 pages, 6 figures, 4 tables, supplementary data associated with
this article can be found, in the online version, at
https://doi.org/10.1016/j.molliq.2021.11815
Transesterificação de óleo de soja com diversos catalisadores alcalinos.
Amostras de óleo de soja neutralizado e seco foram transesterificadas com etanol comercial a 99,5% na presença de quantidades equivalentes de hidróxido, metóxido, etóxido e gliceróxido de sódio como catalisadores. Com o uso dos três alcóxidos obteve-se a separação do glicerol formado durante a reação, o que não ocorreu com o uso de hidróxido de sódio. O rendimento de sódio, como catalisador na transesterificação, apresenta vantagens econômicas e tecnológicas quando comparado com o hidróxido de sódio.bitstream/item/65433/1/CTAA-DOCUMENTOS-12-TRANSESTERIFICACAO-DE-OLEO-DE-SOJA-COM-DIVERSOS-CATALISADORES-ALCALINOS-FL-021.pd
LAGOVirtual: A Collaborative Environment for the Large Aperture GRB Observatory
We present the LAGOVirtual Project: an ongoing project to develop platform to
collaborate in the Large Aperture GRB Observatory (LAGO). This continental-wide
observatory is devised to detect high energy (around 100 GeV) component of
Gamma Ray Bursts, by using the single particle technique in arrays of Water
Cherenkov Detectors (WCD) at high mountain sites (Chacaltaya, Bolivia, 5300 m
a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m
a.s.l). This platform will allow LAGO collaboration to share data, and computer
resources through its different sites. This environment has the possibility to
generate synthetic data by simulating the showers through AIRES application and
to store/preserve distributed data files collected by the WCD at the LAGO
sites. The present article concerns the implementation of a prototype of
LAGO-DR adapting DSpace, with a hierarchical structure (i.e. country,
institution, followed by collections that contain the metadata and data files),
for the captured/simulated data. This structure was generated by using the
community, sub-community, collection, item model; available at the DSpace
software. Each member institution-country of the project has the appropriate
permissions on the system to publish information (descriptive metadata and
associated data files). The platform can also associate multiple files to each
item of data (data from the instruments, graphics, postprocessed-data, etc.).Comment: Second EELA-2 Conference Choroni, Venezuela, November 25th to 27th
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Atividades e práticas em coletivos de trabalho - mutirões - em agroflorestas agroecológicas do litoral do Paraná, Brasil.
O objetivo desse trabalho é a caracterização, análise e discussão das ações praticadas nos mutirões do Grupo de Produtores Agroflorestais Gralha Azul, de Morretes-PR. Dezesseis mutirões do grupo foram acompanhados. As atividades realizadas foram: preparo de canteiro (12 mutirões) e plantio de frutíferas (4). Houve dois tipos de preparo de canteiro: mecanizado e não mecanizado. No mecanizado, com enxada rotativa, em média 7 agricultores em cerca de 6 horas fizeram 121,8 m² de canteiros com largura fixa de 1,20m. Já no não mecanizado, a média foi de 6 agricultores trabalhando cerca de 6 horas fazendo 65,3m² de canteiro com largura média de 0,56 m. Em média nos plantios de frutíferas 6 agricultores trabalharam cerca de 4 horas. A preferência por estas atividades é reflexo tanto do aproveitamento de mão de obra para trabalhos mais árduos quanto pelo fato que a agrofloresta é uma atividade recente. As práticas observadas são recomendações técnicas baseadas na troca de saberes que acontecem entre os técnicos e agricultores e seguem fundamentos agroecológicos.Edição dos resumos do 7º Congresso Brasileiro de Agroecologia, 2013, Porto Alegre
Depth and spatial distribution of blue whiting juveniles in Bay of Biscay
During March-April 1994 and 1996 two cruises have been performed around Bay of Biscay in
order to check movements of blue whiting using acoustic methods. These cruises consisted in
a double coverage of an area from 47°30' N, 7°15' W to 43°30' N, 6°30' W along the French
and Spanish continental shelf-break (200 m to 1000 m).
During these surveys juveniles of blue whiting were found in off-shore pelagic schools. This
paper describes the spatial distribution and depth of these schools around the studied area
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