1,496 research outputs found
Criação de jacaré.
Apresentação; Origem; Reprodução; Espécies; Alimentação; Filhotes; Características; Instalação; Ninho; Utilidade.bitstream/item/98420/1/CPAF-AP-1989-Criacao-jacare.pdfApostila
Fast rotating stars resulting from binary evolution will often appear to be single
Rapidly rotating stars are readily produced in binary systems. An accreting
star in a binary system can be spun up by mass accretion and quickly approach
the break-up limit. Mergers between two stars in a binary are expected to
result in massive, fast rotating stars. These rapid rotators may appear as Be
or Oe stars or at low metallicity they may be progenitors of long gamma-ray
bursts.
Given the high frequency of massive stars in close binaries it seems likely
that a large fraction of rapidly rotating stars result from binary interaction.
It is not straightforward to distinguish a a fast rotator that was born as a
rapidly rotating single star from a fast rotator that resulted from some kind
of binary interaction. Rapidly rotating stars resulting from binary interaction
will often appear to be single because the companion tends to be a low mass,
low luminosity star in a wide orbit. Alternatively, they became single stars
after a merger or disruption of the binary system during the supernova
explosion of the primary.
The absence of evidence for a companion does not guarantee that the system
did not experience binary interaction in the past. If binary interaction is one
of the main causes of high stellar rotation rates, the binary fraction is
expected to be smaller among fast rotators. How this prediction depend on
uncertainties in the physics of the binary interactions requires further
investigation.Comment: 2 pages, 1 figure, to be published in the proceedings of IAU 272
"Active OB stars: structure, evolution, mass loss and critical limit", Paris
19-23 July 201
Fragmento de floresta de transição na zona urbana do Município de Macapá: propostas de estudos e aproveitamento.
bitstream/item/81067/1/AP-2012-Fragmento-floresta-documentos-75.pd
Global Kinetic Model of a Three-Way-Catalyst-Coated Gasoline Particulate Filter: Catalytic Effects of Soot Accumulation
In the present study, a global kinetic model of three-way-catalyst-coated gasoline particulate filters was developed to understand the relevant kinetic mechanisms taking place both in clean and real soot-loaded filters. The model involves reaction rate expressions for CO, C2H4, and C7H8 conversion over a model Pd/CeZr/Al2O3 catalyst, hydrothermally treated at 650 \ub0C. Particularly, a new rate expression was proposed for ethylene based on the distinctive experimental trends observed for this hydrocarbon. The model predicted satisfactorily the conversion of all three reductants under different experimental conditions. The soot inhibition effect was also modeled by the reduction of the number of active sites. Interestingly, ethylene was less affected compared to other reductants by the presence of soot due to the formation of less stable and more reactive species on the catalyst surface
Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool
The absorption and fluorescence properties of chromophoric dissolved organic
matter (CDOM) are reported for the inner shelf, slope waters and outer shelf
regions of the eastern Bering Sea during the summer of 2008, when a warm,
thermally stratified surface mixed layer lay over a cold pool
(< 2 °C) that occupied the entire middle shelf. CDOM absorption
at 355 nm (<i>a</i><sub>g</sub>355) and its spectral slope (<i>S</i>) in conjunction
with excitation–emission matrix (EEM) fluorescence and parallel factor
analysis (PARAFAC) revealed large variability in the characteristics of CDOM
in different regions of the Bering Sea. PARAFAC analysis aided in the
identification of three humic-like (components one, two and five) and two
protein-like (a tyrosine-like component three, and a tryptophan-like component four)
components. In the extensive shelf region, average absorption coefficients at
355 nm (<i>a</i><sub>g</sub>355, m<sup>−1</sup>) and DOC concentrations (μM)
were highest in the inner shelf (0.342 ± 0.11 m<sup>−1</sup>,
92.67 ± 14.60 μM) and lower in the middle
(0.226 ± 0.05 m<sup>−1</sup>, 78.38 ± 10.64 μM) and outer
(0.185 ± 0.05 m<sup>−1</sup>, 79.24 ± 18.01 μM) shelves,
respectively. DOC concentrations, however were not significantly different,
suggesting CDOM sources and sinks to be uncoupled from DOC. Mean spectral
slopes <i>S</i> were elevated in the middle shelf
(24.38 ± 2.25 μm<sup>−1</sup>) especially in the surface waters
(26.87 ± 2.39 μm<sup>−1</sup>) indicating high rates of
photodegradation in the highly stratified surface mixed layer, which
intensified northwards in the northern middle shelf likely contributing to
greater light penetration and to phytoplankton blooms at deeper depths. The
fluorescent humic-like components one, two, and five were most elevated in the inner
shelf most likely from riverine inputs. Along the productive "green belt"
in the outer shelf/slope region, absorption and fluorescence properties
indicated the presence of fresh and degraded autochthonous DOM. Near the
Unimak Pass region of the Aleutian Islands, low DOC and <i>a</i><sub>g</sub>355
(mean 66.99 ± 7.94 μM; 0.182 ± 0.05 m<sup>−1</sup>) and a
high <i>S</i> (mean 25.95 ± 1.58 μm<sup>−1</sup>) suggested substantial
photobleaching of the Alaska Coastal Water, but high intensities of
humic-like and protein-like fluorescence suggested sources of fluorescent DOM
from coastal runoff and glacier meltwaters during the summer. The spectral
slope <i>S</i> vs. <i>a</i><sub>g</sub>355 relationship revealed terrestrial and oceanic
end members along with intermediate water masses that were modeled using
nonlinear regression equations that could allow water mass differentiation
based on CDOM optical properties. Spectral slope <i>S</i> was negatively
correlated (<i>r</i><sup>2</sup> = 0.79) with apparent oxygen utilization (AOU) for waters
extending from the middle shelf into the deep Bering Sea indicating
increasing microbial alteration of CDOM with depth. Although our data show
that the CDOM photochemical environment of the Bering Sea is complex, our
current information on its optical properties will aid in better
understanding of the biogeochemical role of CDOM in carbon budgets in
relation to the annual sea ice and phytoplankton dynamics, and to improved
algorithms of ocean color remote sensing for this region
Mass production of Bacillus subtilis and Trichoderma viride for the control of Phyllosticta citricarpa (Teleomorph: Guignardia citricarpa).
The work was aimed at studying the production of cells and metabolites of Bacilius subtilis (ACB-69) and of Trichoderma viride conidia (ACB-14) on different substrates, since they can potentially control Phyllosticta citricarpa. Our results showed that the medium consisting of cotton meal added of hydrolized protein provided the highest yield of B. subtiiis cells (2.44 x IO9 cells/mL), after the culture had been incubated for three days. This liquid substrate also provided conditions for the bacterium to produce thermostable metabolites, in sufficient amounts to inhibit the plant pathogen's micelial growth. The production of B. subtilis under the solid fermentation system performed better on the brewers rice substrate; the number of bactéria; cells decreased as the substrate concentration increased. In general, the liquid medium yielded a higher amount of B. subtilis than the solid medium. With regard to the large scale production of T. viride, it was verified that the substrates tested had a low spore production; the best substrate among those tested (com cob + hydrolized protein) only yielded 2.17 x IO6 conidia/mL. O objetivo foi estudar a produção de células e de metabólitos de Bacillus subtilis (ACB-69) e de conídios de Trichoderma viride (ACB-14) em diferentes substratos, pois apresentam potencial para o controle de Phyllosticta citricarpa. O meio constituído de farelo de algodão acrescido de proteína hidrolisada foi o que proporcionou maior produção de células de B. subtilis (2,4 x 109 células/mL), após três dias de incubação da cultura. Esse substrato líquido também propiciou condições para que a bactéria produzisse metabólitos termoestáveis e, em quantidades suficientes para inibir o crescimento micelial do fitopatógeno. A produção de B. subtilis pelo sistema de fermentação sólida foi melhor no substrato quirera de arroz sendo que o número de células da bactéria diminuiu à medida que aumentou a concentração do substrato. De um modo geral, o meio líquido foi superior ao sólido para a produção de B. subtilis. Com relação à produção de T. viride, verificou-se que os substratos testados apresentaram baixa produção de esporos, sendo que o melhor substrato testado (sabugo de milho + proteína hidrolisada) produziu apenas 2,2 x 106 conídios/mL
Seleção de linhagens de feijão-caupi para o cerrado do Amapá.
O cerrado do Amapá possui amplas características para a produção de alimentos, sendo o feijão-caupi uma grande opção. Assim, selecionar cultivares para utilização no processo mecanizado deve ser uma meta a ser seguida, sendo este o objetivo do experimento
Genótipos prostrados de feijão-caupi no Cerrado do Amapá.
O cerrado do Estado do Amapá apresenta totais condições para a produção de grãos, sendo o feijão-caupi uma das opções mais viáveis. Assim, selecionar cultivares para este ambiente deve ser uma das metas da pesquisa. No caso em estudo, o experimento objetivou avaliar linhagens de porte prostrado e semi-prostrado. Em Latossolo Amarelo, clima do tipo Ami, usou-se o delineamento experimental de blocos ao acaso e quatro repetições, adubação de 80 kg ha-1 (superfosfato triplo) e 50 kg ha-1 (cloreto de potássio). A semeadura manual ocorreu em fileiras espaçadas de 0,80 m, com área útil de 8 m2 e população de 100 mil plantas ha-1. A análise de variância mostrou diferença significativa pelo teste de Tukey (p< 0,05). O melhor desempenho produtivo de 1.216,7 kg ha-1 foi da linhagem MNC02-676F-1, que apresenta grão da subclasse mulato, seguida pela cultivar BRS-Pajeú com 1.119,0 kg ha-1, com grão da subclasse sempre verde. A linhagem BRS Juruá alcançou menor período de floração, enquanto o maior comprimento de vagem foi do genótipo MNC02-677F-2. Todas as linhagens mostraram tolerância à incidência de doenças.Disponível em: http://www.conac2012.org/resumos/pdf/133c.pdf. Acesso em: 22 jul. 2013
Viveiro de mudas - construção, custos e legalização.
O viveiro; Quanto à duração; Quanto à estrutura; Construção do viveiro; Sistema de irrigação; Relação e custos dos materiais, equipamentos e serviços; Legalização do viveiro.bitstream/item/60594/1/AP-2006-Viveiro-mudas.pdf2. ed. atual. ampl
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