1,908 research outputs found

    Modelling kinetics of thermal degradation of colour in peach puree

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    Optimisation of thermal processes relies on adequate degradation kinetic models for food safety and quality. In order to use peach puree as a model food to further validate calculated optimal conditions, isothermal experiments, using peach puree, were performed between 110°C and 135°C. Colour was quantified using the L, a, b system. Two combinations of these parameters, La/b and Total Colour Difference (TCD), were used to evaluate the total colour change. A one-step non-linear regression was performed on all data using the Arrhenius model. The changes in the L and b values followed a first-order reaction with activation energies of 107 ± 7 and 109 ± 8 kJ/mol, respectively. The fractional conversion model was applied to a, La/b and TCD resulting in activation energies of 106 ± 13, 106 ± 10 and 119 ± 9 kJ/mol, respectively

    Controle biológico de percevejos fitófagos da soja na região de Dourados, MS.

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    Este trabalho teve como objetivo avaliar o parasitismo natural que ocorre em adultos e em ovos do percevejo-marrom da soja Euschistus heros (Fabricius), bem como multiplicar o parasitóide Telenomus podisi (Ashmead) e liberá-lo em lavouras de soja, visando ao controle biológico do percevejo nesta cultura. Durante a safra 2004/2005 e 2005/2006 e nas entressafras de 2004, 2005 e 2006 foram coletados adultos do percevejo, enquanto nas safras de 2003/2004 e 2004/2005 foram coletadas massas de ovos do inseto durante o período reprodutivo da sojabitstream/item/38732/1/BP200740.pdfDocumento on-line

    Controle do percevejo-castanho-da-raiz Scaptocoris carvalhoi, Becker 1967 (Hemiptera: cydnidae) com fungos entomopatogênicos.

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    A pesquisa teve como objetivo avaliar a eficiência de isolados dos fungos Metarhizium anisopliae e Beauveria bassiana como agentes de mortalidade do percevejo-castanho Scaptocoris carvalhoi Becker, 1967. Os experimentos foram conduzidos na Embrapa Agropecuária Oeste, em Dourados, MS. Em condições de laboratório, suspensões de dez isolados de M. anisopliae e 11 de B. bassiana foram aplicadas topicamente no percevejo, inoculando-se 8 5 µl da suspensão de 10 conídios/ml em cada inseto. Utilizou-se o delineamento inteiramente casualizado com cinco repetições. Cada parcela foi constituída por 15 insetos (dez adultos e cinco ninfas grandes). Em outro bioensaio foi avaliada a patogenicidade de M. anisopliae (Ma69) para ninfas e adultos, separadamente. Os níveis de mortalidade do percevejo foram maiores com M. anisopliae, variando de 73,3% a 94,7% contra 10,7% a 78,7% para B. bassiana. Quando ninfas e adultos foram avaliados separadamente não houve diferença significativa com relação à mortalidade. Numa outra etapa, foi avaliada a virulência de quatro isolados do fungo M. anisopliae (Ma7, Ma69, Ma283 e Ma342) em S. carvalhoi e determinadas a DL e o TL . A DL foi determinada 50 50 50 4 5 6 7 8 preparando concentrações de 10 , 10 , 10 , 10 e 10 conídios/ml. Os menores valores da DL foram observados com os isolados 50 Ma69 e Ma7 e o maior com Ma283. Os valores de TL variaram de 50 0,32 a 5,84 dias, sem diferirem estatisticamente entre si. Em casa de vegetação foi avaliada a patogenicidade de um isolado de M. anisopliae (Ma69) em ninfas e adultos de S. carvalhoi, aplicando-se o fungo diretamente no solo dos vasos. Utilizou-se o delineamento inteiramente casualizado em 12 repetições, sendo a parcela constituída por 15 insetos. Para cada fase do inseto (adulto/ninfa) tratada com fungo houve uma testemunha, totalizando quatro tratamentos. Nos vasos contendo o fungo (Ma69), a percentagem de mortalidade de adultos + ninfas de S. carvalhoi foi de 57,3%, sendo estatisticamente superior à mortalidade verificada nos vasos não tratados. Quando ninfas e adultos foram submetidos à presença do fungo, separadamente, o índice de mortalidade foi significativamente maior para ninfas (80,8%) do que para adultos (32,2%). Os resultados obtidos evidenciam que o isolado Ma69 é altamente patogênico para S. carvalhoi, tanto em laboratório quanto em casa de vegetação, constituindo uma alternativa promissora para sua utilização como inseticida microbiano.bitstream/item/38778/1/BP200524.pd

    PT-symmetry from Lindblad dynamics in a linearized optomechanical system

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    We analyze a lossy linearized optomechanical system in the red-detuned regime under the rotating wave approximation. This so-called optomechanical state transfer protocol provides effective lossy frequency converter (quantum beam-splitter-like) dynamics where the strength of the coupling between the electromagnetic and mechanical modes is controlled by the optical steady-state amplitude. By restricting to a subspace with no losses, we argue that the transition from mode-hybridization in the strong coupling regime to the damped-dynamics in the weak coupling regime, is a signature of the passive parity-time (PT) symmetry breaking transition in the underlying non-Hermitian quantum dimer. We compare the dynamics generated by the quantum open system (Langevin or Lindblad) approach to that of the PT-symmetric Hamiltonian, to characterize the cases where the two are identical. Additionally, we numerically explore the evolution of separable and correlated number states at zero temperature as well as thermal initial state evolution at room temperature. Our results provide a pathway for realizing non-Hermitian Hamiltonians in optomechanical systems at a quantum level

    A fuzzy logic model for the analysis of social corporate responsibility

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    Introduction: Critical public opinion, based on information that is made available to the public through different systems, has led companies that operate in the environment to continually improve their social, environmental, and ethical performance. Objectives: This paper aims to propose a fuzzy-logic-based model for the analysis of social corporate responsibility in cases of environmental accidents. Methods: Our study employs techniques derived from social network analysis. The data was collected from the online database of The New York Times for the timespan from March 24, 1989, to September 1, 2017. Results: The results show that the proposed model can be replicated, after some adjustments. Conclusion: We conclude that, despite the complexity of an analysis of this kind in which the model is applied considering isolated words in the text and not the semantic aspects, the proposed model based on fuzzy logic is adequate for the analysis of social corporate responsibility.We would like to thank professors Mariana Claudia Broens, Jose Arthur Quilici Gonzalez and Maria Eunice Quilici Gonzalez for the helpful supervision and indications during the fundamental stages of this research. This paper was supported by the "Understanding opinion and language dynamics using massive data", funded by The São Paulo Research Foundation - FAPESP (reference: 2016/50256-0) (Trans-Atlantic Platform Social Sciences and Humanities, Digging into Data Challenges). We would like to thank the whole team of this project for their discussion and feedback. Ana Claudia Golzio also received support by FAPESP (process number: 2019/08442-9) during the development of this paper, and Mirelys Puerta-Díaz received funding from Coordination for the Improvement of Higher Education Personnel (CAPES) - Financial Code 001

    Creation of blenders in the conservative setting

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    In this work we prove that each C^r conservative diffeomorphism with a pair of hyperbolic periodic points of co-index one can be C^1-approximated by C^r conservative diffeomorphisms having a blender.Comment: 4 figures, 16 figure

    Variability in quality of white and green beans during in-pack sterilization

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    Non-uniformity in process quality was investigated during in-pack thermal sterilization of food products. This was accomplished through the combined application of the Monte Carlo procedure and a reliable mathematical method for process evaluation. Despite the large coefficients of variation found, the optimum quality process could be designed. The influence of the statistical variability of heating rate index on the retention of green beans color was studied and an optimum temperature range was found between 125 and 135 C. The variability in hardness of sterilized white beans, resulting from uncertainties of the combined effect of heating rate index and initial hardness of beans, was also evaluated by simulation. In this case, an optimum global temperature range between 120 and 135 C was found, independently of the rotation, F0 value and surface heat transfer coefficient assumed

    Control of the chemical composition and thickness of deposited coatings over carbon nanotubes using acrylic acid plasma

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    In this study, it is demonstrated that the surface of carbonnanotubes can be coated with a polymer nanometer size film (nanocoating) with tailored surface polar behavior when treated with acrylic acid plasma. The polar behavior of the polymer nanocoating can be hydrophilic or hydrophobic depending deposition and erosion processes caused by ionized species in the plasma. In turn, deposition and erosion can be controlled by plasma power. Deposition dominates at 20 W power, where a significant amount of polymer nanocoating is produced with carboxylic acid functional groups in the surface thus having an hydrophilic behavior. On the contrary, a smaller amount of polymer nanocoating with hydrophobic behavior (i.e. without any functional groups on its surface) suggests that erosion isthe dominant process when 40 W power is used. Finally, a competition between deposition and erosion processes results in different polar behavior and amount of polymer nanocoating depending of the treatment time

    Avaliação da coleção de germoplasma de melancia da Embrapa Hortaliças para tolerância a virose.

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    bitstream/CNPH-2009/31479/1/bpd_12.pd

    Tendências climáticas no município de Pelotas, estado do Rio Grande do Sul, Brasil

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    Changes in the frequency of occurrence of extreme weather events have been pointed out as a likely impact of global warming. In this context, this study aimed to detect climate change in series of extreme minimum and maximum air temperature of Pelotas, State of Rio Grande do Sul, (1896 - 2011) and its influence on the probability of occurrence of these variables. We used the general extreme value distribution (GEV) in its stationary and non-stationary forms. In the latter case, GEV parameters are variable over time. On the basis of goodness-of-fit tests and of the maximum likelihood method, the GEV model in which the location parameter increases over time presents the best fit of the daily minimum air temperature series. Such result describes a significant increase in the mean values of this variable, which indicates a potential reduction in the frequency of frosts. The daily maximum air temperature series is also described by a non-stationary model, whose location parameter decreases over time, and the scale parameter related to sample variance rises between the beginning and end of the series. This result indicates a drop in the mean of daily maximum air temperature values and increased dispersion of the sample data.354769777COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçãoAlterações na frequência de ocorrência dos eventos meteorológicos extremos têm sido apontadas como um provável impacto do aquecimento global. Nesse contexto, objetivou-se detectar a presença de alterações climáticas em séries de temperatura do ar mínima e máxima extremas de Pelotas, Rio Grande do Sul (1896-2011), quantificando sua influência na probabilidade de ocorrência dessas variáveis. Utilizou-se da distribuição geral de valores extremos (GEV) empregada em suas formas estacionária e não estacionárias. Nesse último caso, os parâmetros da GEV são variáveis ao longo do tempo. Com base em testes de aderência e no método da razão da máxima verossimilhança, verificou-se que um modelo GEV em que o parâmetro de localização se eleva ao longo do tempo, apresenta o melhor ajuste da série de temperatura mínima diária. Esse resultado descreve significativa elevação na média dos valores dessa variável, indicando potencial redução na frequência do fenômeno geada. A série de temperatura máxima diária é também descrita por um modelo não estacionário, cujo parâmetro de localização decresce ao longo do tempo e o de escala, relacionado à variância amostral, eleva-se entre o início e o fim da série. Esse resultado indica queda na média dos valores de temperatura máxima diária e elevação da dispersão dos dados amostrais
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