33,655 research outputs found
Enraizamento in vitro de Inhame da Costa (Dioscorea rotundata).
Com o objetivo de otimizar o meio de cultura para promover o enraizamento de plantas de inhame in vitro, microestacas de plantas de Inhame da Costa (Dioscorea rotundata) pré-estabelecidas in vitro foram utilizadas como fonte de explantes iniciais e cultivadas em meios de cultura com diferentes concentrações de sais e vitaminas do MS e doses de carvão ativado. Aos 30 dias, avaliaram-se as seguintes variáveis: altura de planta, número de folhas e de raízes. A utilização do meio ½ MS com 1,0 g de carvão ativado promoveu um melhor desenvolvimento (maior altura e maior número de folhas) das plantas de inhame. Quando se comparou os diferentes tipos de meio, o meio ½ MS também foi o mais adequado para promover o enraizamento das plantas de inhame in vitro utilizando 0,5 ou 1g L-1 de carvão ativado
Black string corrections in variable tension braneworld scenarios
Braneworld models with variable tension are investigated, and the corrections
on the black string horizon along the extra dimension are provided. Such
corrections are encrypted in additional terms involving the covariant
derivatives of the variable tension on the brane, providing profound
consequences concerning the black string horizon variation along the extra
dimension, near the brane. The black string horizon behavior is shown to be
drastically modified by the terms corrected by the brane variable tension. In
particular, a model motivated by the phenomenological interesting case
regarding Eotvos branes is investigated. It forthwith provides further physical
features regarding variable tension braneworld scenarios, heretofore concealed
in all previous analysis in the literature. All precedent analysis considered
uniquely the expansion of the metric up to the second order along the extra
dimension, what is able to evince solely the brane variable tension absolute
value. Notwithstanding, the expansion terms aftermath, further accomplished in
this paper from the third order on, elicits the successive covariant
derivatives of the brane variable tension, and their respective coupling with
the extrinsic curvature, the Weyl tensor, and the Riemann and Ricci tensors, as
well as the scalar curvature. Such additional terms are shown to provide sudden
modifications in the black string horizon in a variable tension braneworld
scenarioComment: 12 pages, 5 figures, accepted in PR
Symbolic Sequences and Tsallis Entropy
We address this work to investigate symbolic sequences with long-range
correlations by using computational simulation. We analyze sequences with two,
three and four symbols that could be repeated times, with the probability
distribution . For these sequences, we verified that
the usual entropy increases more slowly when the symbols are correlated and the
Tsallis entropy exhibits, for a suitable choice of , a linear behavior. We
also study the chain as a random walk-like process and observe a nonusual
diffusive behavior depending on the values of the parameter .Comment: Published in the Brazilian Journal of Physic
Reproductive aspects of Macrobrachium amazonicum (Decapoda: Palaemonidae) in the State of Amapá, Amazon River mouth.
Macrobrachium amazonicum is an indigenous prawn vastly distributed in basins of South America, widely exploited by artisanal fisheries in northern and northeastern Brazil and, with great potential for aquaculture. This study aimed to investigate general aspects of population structure and reproductive characteristics (size at first maturity, fecundity and reproductive output) of M. amazonicum from two important areas to artisanal prawn fishing located at the mouth of the Amazon River, State of Amapá. The specimens were captured using 20 handcrafted traps called ?matapi?. A number of 5,179 prawns were captured, 2,975 females and 2,195 males resulting in 1.35:1 female to male ratio. Santana Island and Mazagão Velho showed females predominated in the population. A reproductive peak period was observed from January to April/2009 and in December/2010, coinciding with the period of higher rainfall. The recruitment peak occurred in June and July/2009. Egg-bearing females ranged in size (carapace length) from 11.10 to 29.6 mm. Fecundity increased with female size and reached up to 7,417 eggs. This amount of eggs is considered low if compared with other Macrobrachium estuarine species. Mean egg volume increased gradually from 0.121 to 0.24 mm3 during embryogenesis, representing 68.5% of overall increase from Stage I to Stage III. Eggs of M. amazonicum are small; this is typical for Macrobrachium species, which depends on brackish water to complete the larval development. Irrespective of female size, reproductive output of M. amazonicum varied between 4.8 and 21.85% of their body weight into eggs production
Micropropagação de inhame da costa (Dioscorea rotundata) em diferentes intensidades luminosa.
Microestacas de plantas de inhame da costa (Dioscorea rotundata) pré-estabelecidas in vitro foram utilizadas como fonte de explantes iniciais e cultivadas em meio MS, contendo 100 mg L-1 de inositol, 20 mg L-1 de cisteina, 0,20 mg L-1 de ANA, 0,15 mg L-1 de BAP e 0,08 mg L-1 de GA3 testando diferentes intensidade luminosa. Aos 30 dias, avaliaram-se as seguintes variáveis: número de brotos e de folhas e altura de planta. As melhores respostas para os números de brotos formados ocorreram com os explantes cultivados em sala de crescimento 100% iluminada. Contudo verificou-se que a maior média para a altura de planta e a maior número de folhas foi encontrada com 30 % de iluminação
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