210 research outputs found

    Low-cost point-focus solar concentrator, phase 1

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    The results of the preliminary design study for the low cost point focus solar concentrator (LCPFSC) development program are presented. A summary description of the preliminary design is given. The design philosophy used to achieve a cost effective design for mass production is described. The concentrator meets all design requirements specified and is based on practical design solutions in every possible way

    Espectroscopia de infravermelho médio e quimiometria aplicadas a discriminação de acessos de bananeira.

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    O Brasil é o quinto produtor mundial de banana, tendo produzido aproximadamente 6,9 milhões de toneladas em 2010, em uma área aproximada de 487 mil hectares (FAO, 2012). Entretanto, há poucos cultivares para exploração comercial com potencial agronômico, tolerantes às pragas e doenças e que apresentem frutos com boas características pós-colheita e organolépticas. Uma das estratégias à solução desse problema é a seleção de novos genótipos, por meio do melhoramento genético, visando o aumento do valor nutricional e funcional (biofortificação), associado às boas características agronômicas

    Compostos fenólicos em frutos de bananeira.

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    Os compostos fenólicos são encontrados em muitas frutas e a quantificação desses metabólicos revela informações importantes a respeito da qualidade dos alimentos e dos potenciais benefícios à saúde (atividade antioxidante e atitumoral, e.g. - TALCOTT et al., 2003). A banana é amplamente consumida por todas as classes sociais e seu consumo é elevado, alcançando 162 Kg/pessoa/ano em algumas regiões da África (FAO, 2012)

    Análise funcional de genes de importância agronômica em macieira.

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    Neste estudo piloto, o gene repórter GFP foi clonado e testado em plantas de macieira para avaliar a utilização da tecnologia TraitUP

    UV-Vis and CIELAB based chemometric characterization of manihot esculenta carotenoid contents

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    Vitamin A deficiency is a prevalent health problem in many areas of the world, where cassava genotypes with high pro-vitamin A content have been identified as a strategy to address this issue. In this study, we found a positive correlation between the color of the root pulp and the total carotenoid contents and, importantly, showed how CIELAB color measurements can be used as a non-destructive and fast technique to quantify the amount of carotenoids in cassava root samples, as opposed to traditional methods. We trained several machine learning models using UV-visible spectrophotometry data, CIELAB data and a low-level data fusion of the two. Best performance models were obtained for the total carotenoids contents calculated using the UV-visible dataset as input, with R2 values above 90 %. Using CIELAB and fusion data, values around 60 % and above 90 % were found. Importantly, these results demonstrated how data fusion can lead to a better model performance for prediction when comparing to the use of a single data source. Considering all these findings, the use of colorimetric data associated with UV-visible and HPLC data through statistical and machine learning methods is a reliable way of predicting the content of total carotenoids in cassava root samples.To CNPq (National Counsel of Technological and Scientific Development) for financial support (Process n 407323/2013-9), to CAPES (Coordination for the Improvement of Higher Education Personnel (CAPES), and EPAGRI(AgriculturalResearchandRuralExtensionCompanyofSantaCatarina).Theresearchfellowshipfrom CNPqonbehalfofM.Maraschinisacknowledged.TheworkispartiallyfundedbyProjectPropMine,funded bytheagreementbetweenPortugueseFCT(FoundationforScienceandTechnology)andBrazilianCNPq.info:eu-repo/semantics/publishedVersio

    ISOLATION, CHEMICAL CHARACTERIZATION AND BIOLOGICAL ACTIVITIES OF CELL WALL POLYSACCHARIDES OF Laurencia microcladia (RHODOMELACEAE, CERAMIALES)

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    Polissacarídeos de parede celular da alga vermelha Laurencia microcladia foram isolados por tratamento alcalino (KOH 1M, 10 mg NaBH4, temperatura ambiente), produzindo duas subfrações por neutralização (AcOH, pH=5.2) e precipitação com EtOH, respectivamente A e B. Eletroforese em papel revelou a existência de apenas um polissacarídeo por fração. O espectro FT-IR de ambos polissacarídeos mostraram indícios de COH (OH: 3400-3300 cm-, CO: 1260-1000 cm-) e de CHC (1300 – 1000 cm-), típicos em polímeros de parede celular de algas. Um derivado Nglicosil (1640 – 1560 cm-) e baixo conteúdo ácido (0.34 mol%) são traços estruturais encontrados, ao passo que proteínas não foram encontradas. A atividade antimitótica foi observada em larvas de Lytechinus variegatus (ouriço verde), com valores crônicos de 38.18 mg/mL e 267.99 mg/mL para os polissacarídeos A e B, respectivamente. Não foram observados efeitos antagonistas para bradicinina e acetilcolina para os polissacarídeos em testes in vitro com íleo de porco-da-índia. Resultados preliminares apontaram efeito neurotóxico dessas macromoléculas (5mg/100 mL) além de assimetria do tubo neural em embriões de galinha.Cell wall polysaccharides of the red algae Laurencia microcladia were isolated by alkaline treatment (KOH 1M, 10 mg NaBH4, room temperature), yielding two sub-fractions by neutralization (AcOH, pH=5.2) and EtOH precipitation, respectively A and B. Paper electrophoresis revealed the existence of only one polysaccharide in each fraction. FT-IR spectra of both polysaccharides showed signals for COH (OH: 3400-3300 cm-, CO: 1260-1000 cm-) and CHC (1300 – 1000 cm-) typical of cell wall algal polymers. An N-glyco derivative (1640 – 1560 cm-) and a low acidic content (0.34 mol %) were structural features found, while proteins were not detected. Antimitotic activity was observed on Lytechinus variegatus (green bur) larvae, with chronic values of 38.18 mg/mL and 267.99 mg/mL for polysaccharides A and B, respectively. No bradykinin or acetylcholine antagonistic effect was observed when polysaccharides were assayed in vitro in guinea-pig ileum. Preliminary results pointed to neurotoxic effect of these macromolecules (5mg/100 mL) since asymmetry of the neural tube in chick embryo was also found

    Sheep Performance in Italian Ryegrass Swards at Contrasting Sward Heights

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    The objective of this study was to assess the effect of Italian ryegrass (Lolium multiflorum Lam.) sward height on lamb performance. The experiment was carried out at the Research Station of UFRGS, Eldorado do Sul, Brazil. Yearling no-castrated male lambs were assessed in terms of individual animal performance and gain per hectare. The experiment was carried out in a randomised block design with three replications of four treatments: 5, 10, 15 and 20 cm of sward surface height (SSH), which were maintained using continuous variable stocking, and monitored by a sward stick. Samples of 0.25 m2 were cut to ground level to estimate herbage and leaf lamina mass. Live weight gain per area and per animal increased in a quadratic pattern. The best animal production was found in a sward of approximately 15 cm high

    A machine learning and chemometrics assisted interpretation of spectroscopic data: a NMR-based metabolomics platform for the assessment of Brazilian propolis

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    In this work, a metabolomics dataset from 1H nuclear magnetic resonance spectroscopy of Brazilian propolis was analyzed using machine learning algorithms, including feature selection and classification methods. Partial least square-discriminant analysis (PLS-DA), random forest (RF), and wrapper methods combining decision trees and rules with evolutionary algorithms (EA) showed to be complementary approaches, allowing to obtain relevant information as to the importance of a given set of features, mostly related to the structural fingerprint of aliphatic and aromatic compounds typically found in propolis, e.g., fatty acids and phenolic compounds. The feature selection and decision tree-based algorithms used appear to be suitable tools for building classification models for the Brazilian propolis metabolomics regarding its geographic origin, with consistency, high accuracy, and avoiding redundant information as to the metabolic signature of relevant compounds.The work is partially funded by ERDF -European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT (Portuguese Foundation for Science and Technology) within projects ref. COMPETE FCOMP-01-0124-FEDER-015079 and PEstOE/ EEI/UI0752/2011. RC's work is funded by a PhD grant from the Portuguese FCT ( ref. SFRH/BD/66201/2009)

    Fidedignidade da versão em português do Inventário de Ansiedade e Fobia Social (SPAI) em amostra heterogênea de estudantes universitários brasileiros

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    Objetivo: Avaliar consistência interna e estabilidade temporal, através de fidedignidade teste-reteste, da versão em português do Inventário de Ansiedade e Fobia Social (SPAI), em uma amostra brasileira heterogênea. Métodos: Após consentimento informado, a versão traduzida e adaptada para o português do SPAI foi testada e re-testada, com 14 dias de intervalo, em uma amostra de 225 estudantes universitários de ambos os gêneros, de quatro cursos de graduação. Após dupla entrada de dados, a análise estatística incluiu Alfa de Cronbach e os coeficientes de correlação de Pearson e Intra-classe. Resultados: A amostra estudada consistiu de 213 estudantes de quatro sub-amostras: 95 estudantes de Direito, 31 de Comunicação Social, 54 de Engenharia Civil e 33 de Odontologia. A média de idade foi de 23 anos (± 6) e 110 (51,6%) eram do gênero feminino. O Alpha de Cronbach foi de 0,96, sem diferenças entre os gêneros. O escore diferencial (total) do SPAI português apresentou coeficiente de Pearson de 0,83 (IC95% 0,78-0,87) e coeficiente Intra-classe de 0,83 (IC95% 0,78-0,86). Não houve diferença estatística nos coeficientes de Pearson entre os gêneros (p = 0,121) ou entre as quatro sub-amostras (p = 0,258). Conclusão: Os resultados não asseguram validade; a versão do SPAI português apresentou boa homogeneidade de conteúdo com nível satisfatório consistência interna. A estabilidade temporal avaliada foi consistente. Os dados demonstram que o SPAI português apresenta fidedignidade perfeitamente aceitável para ambos os gêneros e sugerem sua utilização na população brasileira.Objective: Tto evaluate internal consistency and temporal stability trough test re-test reliability of the Portuguese version of the Social Phobia and Anxiety Inventory (SPAI) in a heterogeneous Brazilian sample. Methods: After informed consent, the translated and adapted version of the SPAI Portuguese was tested and re-tested at a 14-day interval in a sample of 225 university students, both genders, from 4 different undergraduate courses. After double data entry, statistical analysis included Cronbach’s alphas, Pearson and intra-class correlation coefficients. Results: The studied sample consisted of 213 students from 4 sub-samples: 95 law students, 31 social communication students, 54 civil engineering students and 33 dental medicine students. The mean age was 23 (±6) years and 110 (51.6%) were female. The Cronbach’ alpha was 0.96, no difference for both genders. The differential (total) score of the SPAI Portuguese showed Pearson coefficient 0.83 (95% CI 0.78-0.87) and Intra-class coefficient 0.83 (95% CI 0.78-0.86). There was no statistical difference in Pearson coefficients between genders (p = 0.121) and the 4 sub-samples (p = 0.258). Conclusion: The results do not ensure validity, however, the SPAI Portuguese version presented a good content homogeneity with satisfactory level of internal consistency. The temporal stability evaluated was substantial. The results showed that the Portuguese SPAI presents perfectly acceptable reliability for both genders and suggest that it can be used in Brazilian population
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