3,935 research outputs found

    Avaliação do crescimento de mudas de Eucalyptus benthamii após o uso de Bacsol®.

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    Em função do crescente plantio de Eucalyptus benthamii em regiões frias, existe grande demanda por mudas, contudo esta espécie apresenta dificuldades no seu desenvolvimento. Para contornar este tipo de problema, alguns produtos biotecnológicos têm sido usados para estimular o crescimento de mudas. Assim, o objetivo deste trabalho foi avaliar o uso do produto biotecnológico Bacsol® para aumentar o crescimento de mudas de E. benthamii. Este produto é um formulado constituído em sua maioria por esporos bacterianos, que atua como agente estimulador do crescimento de plantas, permitindo que cresçam em menor tempo e com uma melhor qualidade. Para este experimento utilizou-se um delineamento de blocos ao acaso, contendo cinco tratamentos e cada tratamento com 240 mudas, sendo uma testemunha e as doses crescentes do produto (0,5 g; 1 g; 1,5 g; 2 g/muda), em três blocos. Os resultados mostraram que houve aumento significativo da altura das mudas de acordo com o aumento da dosagem do produto (p < 0,001).Resumo expandido

    Importância do uso de rizobactérias na produção de mudas florestais.

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    NEAR-SURFACE EFFECTS IN MODELLING OSCILLATIONS OF ETA BOO

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    Following the report of solar-like oscillations in the G0 V star eta Boo (Kjeldsen et al. 1995, AJ 109, 1313), a first attempt to model the observed frequencies was made by Christensen-Dalsgaard et al. (1995, ApJ Letters, in press). This attempt succeeded in reproducing the observed frequency separations, although there remained a difference of about 10 microHz between observed and computed frequencies. In those models, the near-surface region of the star was treated rather crudely. Here we consider more sophisticated models that include non-local mixing-length theory, turbulent pressure and nonadiabatic oscillations.Comment: uuencoded and compressed Postscript (2 pages, including figure); To appear in Proceedings of IAU Colloquium 155, "Astrophysical Applications of Stellar Pulsation", Cape Town, South Afric

    Current status of the whitefly Aleurodicus dispersus as an invasive pest in the CapeVerte Islands

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    In the last three decades, the spiralling whitefly (Aleurodicus dispersus) has become an important international pest. The movement of plants and parts of plants (such as fruits) in international trade and tourism, and by natural dispersal, has favoured its introduction to new areas. In common with others whiteflies of economic importance, the immature and adult stages cause direct feeding damage by piercing and sucking of sap from foliage, and indirect damage following the accumulation all over host plants of honeydew and waxy flocculent material produced by the insects. Spiralling whitefly is a pest of tropical and subtropical crops, and highly polyphagous. Up to the 1970s, it had been recorded on 44 genera of plants, belonging to 26 botanical families (Mound & Halsey, 1978). This situation changed with the dispersal of the pest to new areas. Nowadays, the spiralling whitefly is one of the major pest of vegetable, ornamental and fruit crops around the globe (Lambkin, 1999). Important host crops include: banana (Musa sapientum), Citrus spp., coconut (Cocos nocifera), eggplant (Solanum melanogena), guava (Psidium guajava), Hibiscus rosa sinensis, Indian almond (Terminalia catappa), papya (Carica papaya), Rosa sp. and tomato (Lycopersicon esculentum) (Saminathan & Jayaraj, 2001). Spiralling whitefly has its origin in the tropical Americas, including Brazil. Although the pest has been recorded only once in Brasil, in the 1920s in the state of Bahia (Bondar, 1923), it now has official quarantine status because of its economic importance. In the Cape Verte Islands, on the West African coast, the pest was initially introduced in the first half of 2000; it has since become established, reaching urban, natural and agricultural areas of the islands that constitute the archipelago. Since then, the pest has been causing damage to many native plants, ornamentals and cultivated food crops (Anon., 2001; Monteiro, 2004). The present study was done in order to produce an inventory of the most common host plants of spiralling whitefly in this new habitat

    An instability of higher-dimensional rotating black holes

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    We present the first example of a linearized gravitational instability of an asymptotically flat vacuum black hole. We study perturbations of a Myers-Perry black hole with equal angular momenta in an odd number of dimensions. We find no evidence of any instability in five or seven dimensions, but in nine dimensions, for sufficiently rapid rotation, we find perturbations that grow exponentially in time. The onset of instability is associated with the appearance of time-independent perturbations which generically break all but one of the rotational symmetries. This is interpreted as evidence for the existence of a new 70-parameter family of black hole solutions with only a single rotational symmetry. We also present results for the Gregory-Laflamme instability of rotating black strings, demonstrating that rotation makes black strings more unstable.Comment: 38 pages, 13 figure

    Estudo sobre a viabilidade de remediação de pesticidas por ectomicorrizas e avaliação da sua tolerância em exposição ao glifosato.

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    Os fungos ectomicorrízicos (ECM) têm sido utilizados na produção de mudas florestais de qualidade. Neste trabalho, levantou-se a hipótese de que estes microrganismos também auxiliariam na degradação de moléculas orgânicas de pesticidas (xenobiontes) registrados no setor florestal. Este trabalho teve como objetivo avaliar a tolerância de fungo ectomicorrízico em exposição ao herbicida glifosato. O xenobionte atrasou o desenvolvimento do fungo ECM-Un01, no entanto a dose testada não foi suficiente para impedir seu desenvolvimento posterior. Existem, portanto, indícios do isolado ECM-Un01 ser tolerante ao glifosato, na dose utilizada.Resumo expandido
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