336 research outputs found

    Efeitos de doses e formas de aplicação de reguladores de crescimento em uvas sem sementes, cv. BRS Clara, em região tropical.

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    O objetivo deste trabalho foi avaliar o efeito do uso dos reguladores vegetais, ácido giberélico e tidiazuron, no tamanho de bagas da cultivar BRS Clara em Região Tropical. Os experimentos foram conduzidos em 2006 e 2007, na Estação Experimental de Viticultura Tropical, em Jales-SP, região noroeste do Estado de São Paulo, em plantas da cv. BRS Clara. Foram testadas diferentes concentrações de GA3 aplicadas isoladamente, combinadas com Crop Set ou tidiazuron, em aplicações únicas ou sequênciais (2 e 4 vezes). As avaliações foram feitas por ocasião da maturação das uvas, considerando-se a massa fresca dos cachos, dos engaços e das bagas, determinadas por meio de balança analítica; o comprimento e o diâmetro médio das bagas, utilizando-se de paquímetro; e o teor de sólidos solúveis (SS), por meio de refratômetro manual. Os experimentos foram conduzidos em delineamento experimental de blocos casualizados, representados por uma planta, com 15 repetições, no ano de 2006, e 10 repetições, no ano de 2007. Os dados foram submetidos à análise de variância e, para a comparação das médias dos tratamentos, foi utilizado o teste Skott Nott, ao nível de 5% de probabilidade. Observou-se que o uso dos reguladores promoveu o crescimento das bagas na cultivar BRS Clara em todos os tratamentos, diferindo da testemunh

    Gains from selection to improve carotenoids content in cassava roots

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    Self‐assembled quantum dots of InSb grown on InP by atomic layer molecular beam epitaxy: Morphology and strain relaxation

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    Self-organized InSb dots grown by atomic layer molecular beam epitaxy on InP substrates have been characterized by atomic force and transmission electron microscopy. Measurement of high-energy electron diffraction during the growth indicates a Stransky–Krastanov growth mode beyond the onset of 1.4 InSb monolayer ~ML! deposition. The dots obtained after a total deposition of 5 and 7 ML of InSb present a truncated pyramidal morphology with rectangular base oriented along the ^110& directions, elongated towards the @110# direction with 111111%B lateral facets, with 113%/114114%/111%A lateral facets in @11 ¯ 0# views, and ~001! flat top surfaces. The mismatch between the dot and the substrate has been accommodated by a network of 90° misfit dislocation at the interface. A corrugation of the InP substrate surrounding the dot has been also observedThis work has been funded by the Spanish CICYT Project MAT95-0966.Peer reviewe

    Gigantism: microsurgical treatment by transsphenoidal approach and prognostic factors

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    Purpose: We present the results of transsphenoidal microsurgical treatment in 14 patients with gigantism. The influence on the prognosis of factors such as the tumor size and preoperative levels of GH and IGF-1 is also quantified. Materials and methods: The patients, operated between 1982 and 2004, were reviewed retrospectively in June 2022. All patients had complete endocrinological studies in the preoperative period and a postoperative control between 6 days and 3 weeks. Follow-up has been supported with annual check-ups between 3 and 31 years. We have compared the preoperative levels of GH and IGF-1 of these patients with the levels of a series of acromegalic patients operated on in the same Center. Results: In this series there were 4 women and 10 men. The age ranged between 14 and 21 years. In 6 patients, postoperative hormone levels achieved the disease control criteria (42.8%). The CT/MRI studies revealed the existence of invasive tumors in 10 of the patients (71.4%). Postoperative CT/MRI showed no tumor tissue in 3 patients but in 7 patients there were tumor remains. The remaining 4 patients had abnormal images although not considered as tumor. A statistical comparison of preoperative serum GH and IGF-1 levels in patients with gigantism and patients with acromegaly showed a significant elevation in the former. Conclusion: Pituitary adenomas that cause gigantism are generally large and invasive, which makes them difficult to cure. High preoperative levels of GH and IGF-1 are also factors that decrease remission

    Effects of solar irradiation on thermally driven CO2 methanation using Ni/CeO2-based catalyst

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    Utilization of the renewable energy sources is one of the main challenges in the state-of-the-art technologies for CO2 recycling. Here we have taken advantage of the solar light harvesting in the thermocatalytic approach to carbon dioxide methanation. The large-surface-area Ni/CeO2 catalyst produced by a scalable low-cost method was characterized and tested in the dark and under solar light irradiation conditions. Light-assisted CO2 con-version experiments as well as in-situ DRIFT spectrometry, performed at different illumination intensities, have revealed a dual effect of the incident photons on the catalytic properties of the two-component Ni/CeO2 catalyst. On the one hand, absorbed photons induce a localized surface plasmon resonance in the Ni nanoparticles fol-lowed by dissipation of the heat to the oxide matrix. On the other hand, the illumination activates the photo-catalytic properties of the CeO2 support, which leads to an increase in the concentration of the intermediates being precursor for methane production. Analysis of the methane production at different temperatures and illumination conditions has shown that the methanation reaction in our case is controlled by a photothermally- activated process. The used approach has allowed us to increase the reaction rate up to 2.4 times and conse-quently to decrease the power consumption by 20 % under solar illumination, thus replacing the conventional thermal activation of the reaction with a green energy source

    Efeitos de reguladores de crescimento em uvas sem sementes, cv. BRS Clara, em Região Tropical.

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    A BRS Clara é uma cultivar de uva sem sementes, lançada em 2003 pela Embrapa Uva e Vinho, que apresenta, naturalmente, bagas com cerca de 15mm de diâmetro e 20mm de comprimento (CAMARGO et al., 2003). Sendo assim, a aplicação exógena de reguladores de crescimento para aumento do tamanho de bagas pode contribuir para a melhoria da qualidade do cacho e facilitar a comercialização de cultivares de uvas sem sementes (NACHTIGAL et al., 2005)

    Effect of pruning young branches on fruit and seed set in cassava

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    Flowering in cassava is closely linked with branching. Early-flowering genotypes branch low and abundantly. Although farmers prefer late flowering genotypes because of their erect plant architecture, their usefulness as progenitors in breeding is limited by their low seed production. In general, the first inflorescence aborts in cassava. Preventing this abortion would result in early production of seeds and make cassava breeding more efficient. The objective of this study was to assess if pruning young branches prevents the abortion of first inflorescences and promotes early fruit and seed set. Four genotypes with early, late, very late, and no flowering habits were grown under an extended photoperiod (EP) or normal dark night conditions (DN). Additional treatments included pruning young branches at the first or second flowering event and spraying (or not) benzyladenine (BA) after pruning. One genotype failed to flower and was not considered further. For the remaining genotypes, EP proved crucial to induce an earlier flowering, which is a pre-requisite for pruning. Total production of seeds in EP plots was 2,971 versus 150 in DN plots. For plants grown under EP, the average number of seeds per plant without pruning was 3.88, whereas those pruned produced 17.60 seeds per plant. Pruning at the first branching event led to higher number of seeds per plant (26.25) than pruning at the second flowering event (8.95). In general, applying BA was beneficial (38.52 and 13.98 seeds/plant with or without spraying it, respectively). The best combination of treatments was different for each genotype. Pruning young branches and applying BA in the first flowering event not only prevented the abortion of inflorescences but also induced the feminization of male flowers into hermaphrodite or female-only flowers. The procedures suggested from this study (combining EP, pruning young branches, and spraying BA), allowed the production of a high number of seeds from erect cassava genotypes in a short period. The implementation of these procedures will improve the breeding efficiency in cassava

    Flower-inducing technology facilitates speed breeding in cassava

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    Cassava is a tropical crop that provides daily carbohydrates to more than 800 million people. New cassava cultivars with improved yield, disease resistance, and food quality are critical to end hunger and reduce poverty in the tropics. However, the progress of new cultivar development has been dragged down by difficulties obtaining flowers from desired parental plants to enable designed crosses. Inducing early flowering and increasing seed production are crucial to improving the efficiency of developing farmer-preferred cultivars. In the present study, we used breeding progenitors to evaluate the effectiveness of flower-inducing technology, including photoperiod extension, pruning, and plant growth regulators. Photoperiod extension significantly reduced the time to flowering in all 150 breeding progenitors, especially late-flowering progenitors which were reduced from 6-7 months to 3-4 months. Seed production was increased by using the combination of pruning and plant growth regulators. Combining photoperiod extension with pruning and the PGR 6-benzyladenine (synthetic cytokinin) produced significantly more fruits and seeds than only photoperiod extension and pruning. Another growth regulator, silver thiosulfate, commonly used to block the action of ethylene, did not show a significant effect on fruit or seed production when combined with pruning. The present study validated a protocol for flower induction in cassava breeding programs and discussed factors to consider in implementing the technology. By inducing early flowering and increasing seed production, the protocol helped move one step further for speed breeding in cassava
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