5,274 research outputs found

    Caracterização da biomassa das microalgas Micractinium sp. e Chlamydomonas biconvexa cultivadas em vinhaça e CO2 para aplicações biotecnológicas.

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    Dissertação (Mestrado) - Universidade Federal do Tocantins, Gurupi, TO. Orientador CNAPE: Bruno dos Santos Alves F. Brasil. Co-orientadora CNPAE: Itânia Pinheiro Soares

    Evaluation of the Acute Effects of Organic Solvents on Adults of Sitophilus zeamais Motschulsky, 1855 (Coleoptera, Curculionidae)

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    The continuous use of synthetic insecticides has created problems for the environment and human health. With the objective of reducing such problems, ecofriendly measures have been taken and, in this case, plants have representing an important resource for pest control. Due to the increase of studies using organic extracts in bioassays and the difficulty of finding solubilizant agents that do not interfere in the results, the aim of this work was to evaluated the acute effect of different solvents on Sitophilus zeamais by contact and ingestion assays. The results suggest that pure dimethyl sulphoxide (DMSO) and Tween- 20 solvents have toxic acute effects on adults of S. zeamais, but they can be used diluted at 1 or 5% with no toxic acute effect. On contrary, pure dichloromethane (DCM) and methanol (MeOH) did not cause any acute effect on target organism. Thus, DCM and MeOH solvents even in the pure form and the Tween-20 and DMSO diluted at 1 or 5% can be used as solubilizant agents for apolar to medium polarity plant extracts, involving contact or ingestion assay on adults of S. zeamais. Keywords: plant extracts, stored grain pest, solvents, toxicity

    Recovery of phenolic compouns by solid-state fermentation from grape pomace and wheat bran.

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    The grape pomace and wheat bran is rich in bioactive compounds that may be conjugated to the plant cell wall, making it difficult to recover. The objective of this study was to produce an enzymatic complex concomitant to the release of phenolics from grape pomace and wheat bran, by solid-state fermentation (SSF), using the mutant strain Aspergillus niger 3T5B8. Both substrates showed potential for the production of hydrolytic enzymes, mainly for xylanase and ?-glucosidase enzymes with grape pomace and wheat bran, respectively. In addition, SSF showed a more than 50% increase in the phenolic release of the substrates.SINAFERM; SHEB. 3 a 6 de setembro. Seção Trabalhos. Ref. 56515

    Unsteady undular bores in fully nonlinear shallow-water theory

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    We consider unsteady undular bores for a pair of coupled equations of Boussinesq-type which contain the familiar fully nonlinear dissipationless shallow-water dynamics and the leading-order fully nonlinear dispersive terms. This system contains one horizontal space dimension and time and can be systematically derived from the full Euler equations for irrotational flows with a free surface using a standard long-wave asymptotic expansion. In this context the system was first derived by Su and Gardner. It coincides with the one-dimensional flat-bottom reduction of the Green-Naghdi system and, additionally, has recently found a number of fluid dynamics applications other than the present context of shallow-water gravity waves. We then use the Whitham modulation theory for a one-phase periodic travelling wave to obtain an asymptotic analytical description of an undular bore in the Su-Gardner system for a full range of "depth" ratios across the bore. The positions of the leading and trailing edges of the undular bore and the amplitude of the leading solitary wave of the bore are found as functions of this "depth ratio". The formation of a partial undular bore with a rapidly-varying finite-amplitude trailing wave front is predicted for ``depth ratios'' across the bore exceeding 1.43. The analytical results from the modulation theory are shown to be in excellent agreement with full numerical solutions for the development of an undular bore in the Su-Gardner system.Comment: Revised version accepted for publication in Phys. Fluids, 51 pages, 9 figure

    Anastrepha species (Diptera: Tephritidae), their hosts and parasitoids in the extreme north of Brazil.

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    O presente trabalho foi realizado em cinco municípios do Estado de Roraima, Brasil, com o objetivo de registrar a ocorrência de espécies de Anastrepha, suas plantas hospedeiras e parasitoides. Foram coletados frutos carnosos de 21 espécies pertencentes a 10 famílias botânicas de setembro/2007 a setembro/2008. Foram identificadas 10 espécies de Anastrepha (Anastrepha bahiensis Lima e Anastrepha montei Lima foram registradas pela primeira vez em Roraima) e cinco espécies de parasitoides (4 Braconidae e 1 Figitidae). Doryctobracon areolatus (Szépligeti) foi o parasitoide mais abundante
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