1,971 research outputs found

    Discriminação de sistemas de preparo do solo para plantio de soja por meio de EVI-2 aplicados a dados do sensor Worldview-2.

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    O objetivo deste trabalho foi, portanto, avaliar a eficácia do EVI-2 na discriminação de diferentes sistemas de preparo do solo para plantio de soja

    Avaliação da vulnerabilidade sísmica do núcleo urbano antigo do Seixal

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    A avaliação do risco sísmico, tal como de outros fenómenos naturais, tem vindo a ganhar protagonismo ao longo das últimas décadas, sendo considerado primordial na definição de estratégias de planeamento e gestão urbana. A avaliação da vulnerabilidade sísmica de edifícios existentes, na perspectiva da mitigação do risco sísmico, deve colocar-se não só em relação aos edifícado monumental ou culturalmente valiosos, mas também em relação a aglomerados de edifícios em núcleos urbanos, particularmente nos núcleos urbanos antigos. A análise do desempenho de edifícios em sismos recentes tem permitido identificar quais os aspectos estruturais que mais influenciam a sua vulnerabilidade e o desenvolvimento de mecanismos de danos. Neste artigo analisam-se os resultados da avaliação da vulnerabilidade sísmica do núcleo urbano antigo do Seixal, obtidos através da aplicação de uma metodologia baseada num índice de vulnerabilidade. Através da avaliação da vulnerabilidade sísmica, esta metodologia permite ainda estimar dano e criar cenários de perda. Estes resultados serão apresentados tirando partido de uma ferramenta integrada num Sistema de Informação Geográfica (SIG)

    Polysaccharide/protein nanomultilayer coatings: construction, characterization and evaluation of their effect on 'Rocha' pear (Pyrus communis L.) shelf-life

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    Nanolayered coatings of κ-carrageenan, a polysaccharide with good gas barrier properties, and lysozyme, a protein with antimicrobial action, were in a first stage assembled on aminolysed/charged polyethylene terephthalate (PET) pieces, which acted as a support, by alternate five-layer deposition. This was performed to allow the characterization of the nanomultilayer system. PET aminolysis was confirmed by Fourier transform infrared spectroscopy and contact angle, and the subsequent layer adsorption on aminolysed PET surface was confirmed by absorbance, contact angle and SEM images. The water vapour permeability and the oxygen permeability (O2P) of the five layers were found to be 0.013 ± 0.003 × 10−11 and 0.1 ± 0.01 × 10−14 g m−1 s−1 Pa−1, respectively. The nanomultilayer system was subsequently applied (without PET support) directly on ‘Rocha’ (Pyrus communis L.) fresh-cut pears and whole pears. Uncoated fresh-cut pears and whole pears presented higher mass loss, higher total soluble solids (TSS) and lower titratable acidity when compared with coated fresh-cut pears and whole pears. Uncoated fresh-cut pears also presented a darker colour. These results showed that the nanolayered coating assembled on the fruits’ surface has a positive effect on fruit quality and contributed to extend the shelf-life.Author Bartolomeu G. de S. Medeiros was a recipient of a scholarship from the project Isac (Isac Mundus Cooperation, European Union) and is also a recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Capes, Brazil). Author A. C. Pinheiro is recipient of a fellowship (SFRH/BD/48120/2008) from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal)

    A comparison of deformed wing virus in deformed and asymptomatic honey bees

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    Deformed wing virus (DWV) in association with Varroa destructor is currently attributed to being responsible for colony collapse in the western honey bee (Apis mellifera). The appearance of deformed individuals within an infested colony has long been associated with colony losses. However, it is unknown why only a fraction of DWV positive bees develop deformed wings. This study concerns two small studies comparing deformed and non-deformed bees. In Brazil, asymptomatic bees (no wing deformity) that had been parasitised by Varroa as pupae had higher DWV loads than non-parasitised bees. However, we found no greater bilateral asymmetry in wing morphology due to DWV titres or parasitisation. As expected, using RT-qPCR, deformed bees were found to contain the highest viral loads. In a separate study, next generation sequencing (NGS) was applied to compare the entire DWV genomes from paired symptomatic and asymptomatic bees from three colonies on two different Hawaiian islands. This revealed no consistent differences between DWV genomes from deformed or asymptomatic bees, with the greatest variation seen between locations, not phenotypes. All samples, except one, were dominated by DWV type A. This small-scale study suggests that there is no unique genetic variant associated with wing deformity; but that many DWV variants have the potential to cause deformit

    Processing of byproducts to improve nisin production by Lactococcus lactis

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    In the last years, disposal from dairy industries have received a special attention due its polluting power in the environment. For this reason, studies have obtained a positive support to develop different alternatives to recycle milk whey components. One of them is its utilization as culture media, aiming to produce biomolecules with noble applications. Nisin is an extracellular peptide, produced by Lactococcus lactis, this peptide has been applied as a natural additive once it presents broad antibacterial activity. Applications of this bacteriocin include dental care products, pharmaceutical products such as stomach ulcers and colon infection treatment and potential birth control. In batch cultures, L. lactis was performed in two different groups of assays. The first group milk whey was prepared in distilled water in four different concentrations: 100 g/l (S100); 50 g/l (S50); 30 g/l (S30); 10 g/l (S10). In the second group of assays, two supplements were added in milk whey with concentration 100 g/l (S100): (1) 5 g/l yeast extract (A1); (2) 5 g/l yeast extract and 10 ml (v/v) tomato extract. Nisin activity was assayed through agar diffusion utilizing Lactobacillus sakei. The results show that the utilization of powder milk whey with concentration of 100 g/l can be used as a culture medium with supplementation. This media is favorable to develop L. lactis cells and nisin production, reaching an activity of about 4 logAU. Biological processing of milk byproduct can be considered as one of the profitable utilization alternatives, generating high-value bioproducts and stimulates researches for its use.The authors wish to thank the Brazilian Committees for the Scientific Technology Research (CNPq, FAPESP, CAPES), for financial support and scholarship

    Nisin biotechnological production : evaluation and perspectives in the development of new applications

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    Nisin is a commercially available bacteriocin of the lantibiotic group produced by Lactococcus lactis ATCC 11454. The importance of nisin as an effective preservative is the fact that its spectrum of inhibitory activity includes almost all Gram-positive, Gram-negative and spoilage bacteria. With several favorable characteristics, this compound has been widely used as a natural food biopreservative. On the other hand, biotechnological production of fuel ethanol from different raw materials (sucrose-containing feedstocks - mainly sugar cane, starchy materials and lignocellulosic biomass) has led to the increase in the researches with trends for improving the bio-ethanol production. During these processes of bio-ethanol production antibiotic agents are added to the pre-fermented broth to prevent unwanted microbial growth. Thus, different questions have been made in relation to performance of the application of the nisin as a natural antibiotic to the ethanol production, as well as their beneficial effects about the yield and productivity in this process. However, the solution to this problematic depends firstly on how the development and implementation of technologies based on nisin production will be undertaken. Perspectives towards the development of modern procedures of nisin production are still needed. In this work the main proposal that has been discussed is the applicability of a novel micro-reactor operated under oscillatory flow mixing envisaged for parallel screening and/or development of industrial bioprocesses in the nisin production. For this reason, initially the objective of this study was to investigate the milk whey, a byproduct from dairy industries, in nisin production aiming to evaluate the growth conditions for L. lactis. In batch cultures, L. lactis was performed in raw milk whey and the nisin activity was assayed through agar diffusion utilizing Lactobacillus sakei ATCC 15521. The results showed that milk whey media is propitious to develop L. lactis cells and produce nisin, reaching activity around 105 AU.mL-1. Biological processing of milk sub-products (milk whey) can be considered one of profitable utilization alternatives, generating high-value bioproducts and contributing to decrease rivers disposal. The use of these sub-products as substrate together with further studies related to application of batch or continuous oscillatory flow reactor would take the more efficient nisin production and finally to a possibility of its evaluation and use in bio-ethanol production.Fundação para a Ciência e a Tecnologia (FCT)FAPESP/BrasilCAPES/Brasi

    Evaluation of a hydrothermal process for pretreatment of wheat straw : effect of particle size and process conditions

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    Hydrothermal processes are an eco-friendly processes that provide an interesting alternative for chemical utilization of lignocellulosic materials, in which water and crop residues are the only reagents. In this work the effect of process conditions (size distribution of the wheat straw, temperature and time) was evaluated against production of fermentable products. RESULTS: The use of milled wheat straw fractions as a raw material containing blends of different particle size distribution showed that the latter had an influence on the final sugars in the hydrolysate. Improved values of glucose (21.1%) and xylose yields (49.32%) present in the hydrolysate were obtained with treatment severity factors of 2.77 and 3.36, respectively. Mathematical models were developed aimed at establishing the effect of process conditions on monosaccharide concentration and its degradation in the liquor. CONCLUSION: This work shows that the use of wheat straw blends with various particle sizes has a significant effect on the extraction of fermentable products. The effect of treatment severity, which takes into account both processing time and temperature was also evaluated. These results are of importance for process design.ALBAN programm
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