46 research outputs found

    Methods of application and dosages of insecticides for Aphis gossypii (Glover) (Hemiptera: Aphididae) in the yellow melon

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    [PT] - Para aperfeiçoar o manejo fitossanitário de pragas na cultura do melão (Cucumis melo L.), objetivou-se avaliar os efeitos de formas de aplicação e doses de inseticidas sobre a eficiência de controle químico do pulgão A. gossypii. O experimento foi realizado em 2010, na cidade de Fortaleza, Ceará, com melão amarelo cultivado em condições de campo. O delineamento experimental foi em blocos ao acaso, arranjo fatorial 2 x 4, com quatro repetições e parcelas de seis plantas. Os tratamentos foram duas formas de aplicação (pulverização costal manual e insetigação por gotejamento) e quatro doses de inseticida (0; 50; 100; 200% da dose recomendada pelo fabricante). Os inseticidas acefato e tiametoxam, testados separadamente, foram aplicados em manejo de rotação de grupos químicos. A eficiência de controle foi avaliada sete dias após o uso de cada inseticida. O acefato não apresentou diferença significativa entre as formas de aplicação, atingindo eficiências de controle de 88,95 e 84,09% com 100 e 200% da dose recomendada, respectivamente. O tiametoxam não diferiu significativamente quanto às formas de aplicação e doses testadas, apresentando eficiência de 100% em todos os tratamentos. Atualmente, no Brasil, a utilização de acefato no melão está limitada à aplicação mecanizada devido ao risco de contaminação. Diante dessa limitação, o controle do pulgão em meloeiro amarelo pode ser realizado via insetigação por gotejo ou pulverização costal manual, devendo-se empregar, preferencialmente, 100% da dose recomendada de tiametoxam.[EN] In order to perfect the phytosanitary management of pests in the melon crop (Cucumis melo L.), the aim here was to evaluate the effects of different methods of application and dosages of insecticides on the effectiveness of chemical control of the aphid A. gossypii. The experiment was carried out in 2010, in Fortaleza, in the state of Ceara, Brazil, with yellow melon grown under field conditions. The experimental design was of randomised blocks in a 2 x 4 factorial arrangement, with four replications and lots of six plants. Treatments consisted of two methods of application (manual backpack spray and drip insectigation) and four dosages of insecticide (0, 50, 100 and 200% of the dosage recommended by the manufacturer). The insecticides acephate and thiamethoxam, tested separately, were applied in a rotating management of chemical groups. Efficiency of the control was evaluated seven days after the use of each insecticide. The acephate showed no significant difference between the forms of application, reaching control efficiencies of 88.95 and 84.09% with 100 and 200% of the recommended dose respectively. The thiamethoxam did not differ significantly for the application methods and dosages under test, giving 100% efficiency in all treatments. Currently in Brazil the use of acephate in the melon is limited to mechanised application due to the risk of contamination. Because of this limitation, the control of aphids in yellow melon can be carried out via drip insectigation or backsack spray, with preferably 100% of the recommended dose of thiamethoxam.Do Bomfim, G.; Moreira De Azevedo, B.; Viana, TVA.; Manzano Juarez, J.; Vasconcelos, DV. (2015). Formas de aplicação e doses de inseticidas sobre Aphis gossypii (Glover) (Hemiptera: Aphididae) em melão amarelo. Revista Ciencia Agronomica. 46(3):488-496. doi:10.5935/1806-6690.20150030S48849646

    Design and installation alternatives of Venturi injectors in drip irrigation

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    [ES] En la Universitat Politècnica de València, Valencia, España (39°29¿ N; 0°23¿ W; 20 m), ha sido estudiado el funcionamiento de cuatro prototipos de inyector Venturi y tres formas de instalación distintas. El funcionamiento se ha analizado bajo diversos parámetros, como pérdidas de carga, relación de caudales y rendimiento. Las formas de instalación analizadas han sido: sin inyección y con inyección y presiones negativas o positivas en la garganta. Las presiones se establecieron entre 10 y 40 m.c.a. A partir de los datos experimentales han sido procesados utilizando técnicas de regresión múltiple y análisis de la varianza. Con ellas, fue posible, a través de la integración de geometrías en función de los diámetros, caudales y presiones, obtener expresiones para prever la pérdida de carga o el caudal inyectado. Se pone de manifiesto que la relación de caudales y el rendimiento son mayores cuanto mayor es el diámetro de la aspiración y empeoran al reducirse el diámetro de la garganta, siendo estas las dimensiones que más condicionan la inyección. También, puede afirmarse que la pérdida de carga, para un mismo caudal inyectado, es inferior si la operación se realiza con presiones positivas que con presiones negativas. La relación de caudales o el rendimiento también proporcionan valores más elevados bajo esta forma de instalación propuesta.[EN] The performance and installation alternatives of four Venturi injector prototypes were studied at Universitat Politècnica de València, Valencia, Spain (39°29¿ N; 0°23¿ W; 20 m). This device performance was studied under several parameters such as head loss, relation of flows and injection efficiency. The installation configurations analyzed were: without the injection of nutrients solution and with the injection either having negative or positive pressure at the Venturi throat. The inlet pressures were established between 10 and 40 m.w.c. The experimental data has been processed using multiple stepwise regression techniques and analysis of variance (ANOVA). Moreover, geometry integration versus diameters, flows and pressures is used to obtain some equations for predicting the head loss and injected flow. The results of the present study showed that the relation between flows and injection efficiency were better when the diameter of inlet nutrient line increases and become worse when decreases the diameter of the Venturi throat. Accordingly, these dimensions become very important in the design prototype and installation configuration. Furthermore, after the analysis of laboratory experiments it can be concluded that head losses, at the same injected flow, were lower if the injection was carried out with positive pressures at the throat than in the case of negative pressures. Also in this case, the relationship between flow rates and injection efficiency leaded to a good performance of the proposed installation.Manzano Juarez, J.; Palau, C.; Moreira De Azevedo, B.; Do Bomfim, G.; Vasconcelos, DV. (2015). Diseño y alternativas en la instalación de inyectores Venturi en riego localizado. Revista Ciencia Agronomica. 46(2):287-298. doi:10.5935/1806-6690.20150008S28729846

    Evaluation of the bibliometric scenario of the Delphi method with Brazilian affiliations

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    The Delphi method is a technique used to reach consensus among specialists in an area who will be able to predict demands or analyze conjunctures about strategic themes. Within this context, the present work consisted of a bibliometric evaluation performed in the Scopus database with the aid of VOSviewer software, prioritizing journals with an affiliation of Brazilian institutions and that made use of the Delphi method for the development of their research. Data collection went through validation stages, and the results obtained showed that this tool was used in several areas of knowledge, with great emphasis on health, more specifically in Medicine, Nursing, and Public health. Together, these three areas accounted for more than 60% of publications made available

    Geometría y pérdidas de carga en inyectores Venturi mediante la dinámica de fluidos computacional

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    [EN] To determine the influence of geometry on the hydrodynamic behavior of Venturi injectors, using computational fluid dynamics techniques, we studied, at the Universitat Politècnica de València, Valencia, Spain, the geometric parameters that exert the most influence on head losses: the relationship between throat diameter and nozzle (β), nozzle angle (α1) and diffuser angle (α2). In addition, three throat morphologies (B1: nozzle-throat and throat-diffuser with a sharp edge; B2: nozzle-diffuser with a zero-length, sharp-edge throat; B3: nozzle-throat and throat-diffuser with rounded edge). We analyzed their influence on the velocity distribution and differential pressure between inlet and throat (DP/γ), throat and outlet (Δhv/γ), and outlet and throat ((P3-P2)/γ). The development of the velocity profile from the throat is slower the greater β is and the lower α2 is. DP/γ decreases with β, increases with α1 and varies little with α2. Δhv/γ decreases with β and increases with α1 and α2. (P3-P2)/γ decreases with β and increases with α1 and α2. Geometry B3 decreases the losses and delays the onset of cavitation. Thus, the lower β and the higher α2, the greater the losses; however, the influence of α1 is less clear. The rounded edges produce lower head losses.[ES] Estudio de la influencia de la geometría en el comportamiento hidrodinámico de inyectores Venturi mediante técnicas de dinámica de fluidos computacional. Para determinar la influencia de la geometría en el comportamiento hidrodinámico de inyectores Venturi, mediante técnicas de dinámica de fluidos computacional, se estudió, en la Universitat Politècnica de València, Valencia, España, los parámetros geométricos que más influencian las pérdidas de carga: relación entre diámetro de la garganta y tobera (β), ángulo de la tobera (α1) y ángulo del difusor (α2). Además, tres morfologías de la garganta (B1: tobera-garganta y garganta-difusor en arista viva; B2: tobera-difusor con garganta de longitud nula y en arista viva; B3: tobera-garganta y garganta-difusor en arista redondeadas). Se ha analizado su influencia en la distribución de velocidad y en la presión diferencial entre entrada y garganta (DP/γ), garganta y salida (∆hv/γ), y salida y garganta ((P3-P2)/γ). El desarrollo del perfil de velocidades a partir de la garganta es más lento cuanto mayor es β y menor es α2. DP/γ disminuye con β, aumenta con α1 y es poco variable con α2. ∆hv/γ disminuye con β y aumenta con α1 y α2. (P3-P2)/γ disminuye con β y α1, yaumenta con y α2. La geometría B3 disminuye las pérdidas y retarda la aparición de la cavitación. Así, cuanto menor es β y cuanto mayor es α2, mayores son las pérdidas de carga, sin embargo, la influencia de α1 no es tan clara. Las aristas redondeadas producen menores perdidas de cargaThe authors would like to thank the “Conselleria d'Empresa, Universitat i Ciència” of Generalitat Valenciana – Spain.Manzano Juarez, J.; Palau, CV.; De Azevedo, BM.; Do Bomfim, GV.; Vasconcelos, DV. (2016). Geometry and head loss in Venturi injectors through Computational Fluid Dynamics. Engenharia Agrícola. 36(3):482-491. doi:10.1590/1809-4430-Eng.Agric.v36n3p482-491/2016S482491363Baylar, A., Aydin, M., Unsal, M., & Ozkan, F. (2009). Numerical Modeling of Venturi Flows for Determining Air Injection Rates Using Fluent V6.2. Mathematical and Computational Applications, 14(2), 97-108. doi:10.3390/mca14020097Chan, L., Chin, C., Soria, J., & Ooi, A. (2014). Large eddy simulation and Reynolds-averaged Navier-Stokes calculations of supersonic impinging jets at varying nozzle-to-wall distances and impinging angles. International Journal of Heat and Fluid Flow, 47, 31-41. doi:10.1016/j.ijheatfluidflow.2014.02.005Dantas Neto, J., Maciel, J. L., Alves, A. de S., Azevedo, C. A. V. de, Fernandes, P. D., & Lima, V. L. A. de. (2013). Teores de macronutrientes em folhas de goiabeira fertirrigada com nitrogênio. Revista Brasileira de Engenharia Agrícola e Ambiental, 17(9), 962-968. doi:10.1590/s1415-43662013000900008Rezende, R., Helbel Júnior, C., Souza, R. S. de, Antunes, F. M., & Frizzone, J. A. (2010). Crescimento inicial de duas cultivares de cafeeiro em diferentes regimes hídricos e dosagens de fertirrigação. Engenharia Agrícola, 30(3), 447-458. doi:10.1590/s0100-69162010000300009Sanderse, B., Pijl, S. P., & Koren, B. (2011). Review of computational fluid dynamics for wind turbine wake aerodynamics. Wind Energy, 14(7), 799-819. doi:10.1002/we.458Santos, L. D. C., Zocoler, J. L., Justi, A. L., Silva, A. O., & Correia, J. D. S. (2012). ESTUDO COMPARATIVO DA TAXA DE INJEÇÃO EM INJETOR DO TIPO VENTURI COM E SEM VÁLVULA DE RETENÇÃO. IRRIGA, 1(01), 145. doi:10.15809/irriga.2012v1n01p145Sun, Y., & Niu, W. (2012). Simulating the Effects of Structural Parameters on the Hydraulic Performances of Venturi Tube. Modelling and Simulation in Engineering, 2012, 1-7. doi:10.1155/2012/458368Uribe, R. A. M., Gava, G. J. de C., Saad, J. C. C., & Kölln, O. T. (2013). Ratoon sugarcane yield integrated drip-irrigation and nitrogen fertilization. Engenharia Agrícola, 33(6), 1124-1133. doi:10.1590/s0100-69162013000600005Vasata, D., Galante, G., Rizzi, R. L., & Zara, R. A. (2011). Solução computacional do problema da cavidade cúbica através das equações de Navier-Stokes tridimensionais. Revista Brasileira de Ensino de Física, 33(2), 1-10. doi:10.1590/s1806-11172011000200013Yeoh, G. H., Liu, C., Tu, J., & Timchenko, V. (2012). Computational Fluid Dynamics and Its Applications 2012. Modelling and Simulation in Engineering, 2012, 1-2. doi:10.1155/2012/61061

    Distribuição de potássio em gotejamento com fertirrigação em diferentes pontos de injeção na linha principal

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    [EN] The purpose of this research was to evaluate the K2O distribution uniformity by surface drip irrigation at Universitat Politecnica de Valencia, Valencia, Spain (39º 29′ N, 0º 23′ W, 20 m). The irrigation was performed by drip lines with not-compensated emitters, spaced 0.3 m. The fertigation was realized using a fertilizer injector pump of electric action with injection of 0.25 h. The experimental design used completely randomized blocks with five treatments and four replications. The treatments consisted of injection in five distances, located at 10; 20; 30; 40; 50 m of the first drip line. Samples were collected in emitters located at the start, at 1/3, at 2/3 and at the end of the drip lines. The nutrient concentration was determined by flame spectrophotometry. The Christiansen's uniformity coefficients (CUC), of distribution (DUC), of statistical (SUC) and of emission (eUC) were estimated. The K2O concentration and distribution decreased linearly with the increase of the injection distance. In all treatments, the CUC, SUC and DUC were described as 'excellent'. The eUC was described as 'recommended' only at smaller injection distances.[PT] Objetivando fornecer subsídios para os produtores aperfeiçoarem o manejo da fertirrigação em pequenas áreas, avaliou-se, na Universitat Politècnica de València, Valência, Espanha (39° 29′ N, 0° 23′ W, 20 m), a uniformidade de distribuição do K2O via irrigação por gotejamento superficial em função da distância do ponto de injeção na linha principal. A irrigação foi efetuada por linhas laterais com emissores não compensantes, espaçados de 0,3 m. Na fertirrigação, foi utilizada uma bomba injetora de fertilizante de acionamento elétrico, com o tempo de injeção de 0,25 h. O delineamento experimental foi o de blocos casualizados, com cinco tratamentos e quatro repetições. Os tratamentos consistiram em cinco pontos de injeção na linha principal, situados a: 10; 20; 30; 40 e 50 m da primeira linha lateral. Foram coletadas amostras em emissores localizados no início, a 1/3, a 2/3 e no final das linhas laterais. A concentração do nutriente foi determinada por espectrofotometria de chama. Foram estimados os coeficientes de uniformidade de Christiansen (CUC), de distribuição (CUD), estatístico (CUE) e de emissão (CUe). A concentração e a distribuição de K2O diminuíram linearmente com o aumento da distância do ponto de injeção. Em todos os tratamentos, o CUC, CUE e CUD foram classificados como ‘excelente’. O CUe foi classificado como ‘recomendado’ apenas na menor distância de injeção.To the Coordination of Improvement of Higher Education Personnel (CAPES) for grant the Doctoral Sandwich Abroad scholarship and the Universitat Politècnica de València (UPV), for providing the experimental area and all equipment and supplies needed for the research.Do Bomfim, GV.; Manzano Juarez, J.; De Azevedo, BM.; Vasconcelos, DV.; Viana, TVDA. (2014). Potassium distribution in drip irrigation with fertigation for different injection distances in the main line. Engenharia Agrícola. 34(6):1151-1161. doi:10.1590/S0100-69162014000600011S1151116134

    Zika virus vertical transmission in children with confirmed antenatal exposure.

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    We report Zika virus (ZIKV) vertical transmission in 130 infants born to PCR+ mothers at the time of the Rio de Janeiro epidemic of 2015-2016. Serum and urine collected from birth through the first year of life were tested by quantitative reverse transcriptase polymerase chain reaction (PCR) and/or IgM Zika MAC-ELISA. Four hundred and seven specimens are evaluated; 161 sera tested by PCR and IgM assays, 85 urines by PCR. Sixty-five percent of children (N = 84) are positive in at least one assay. Of 94 children tested within 3 months of age, 70% are positive. Positivity declines to 33% after 3 months. Five children are PCR+ beyond 200 days of life. Concordance between IgM and PCR results is 52%, sensitivity 65%, specificity 40% (positive PCR results as gold standard). IgM and serum PCR are 61% concordant; serum and urine PCR 55%. Most children (65%) are clinically normal. Equal numbers of children with abnormal findings (29 of 45, 64%) and normal findings (55 of 85, 65%) have positive results, p = 0.98. Earlier maternal trimester of infection is associated with positive results (p = 0.04) but not clinical disease (p = 0.98). ZIKV vertical transmission is frequent but laboratory confirmed infection is not necessarily associated with infant abnormalities

    Use of the mini-mental state examination in research on the elderly in Brazil: a systematic review

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    The Mini-Mental State Examination (MMSE) is the most widely used cognitive screening test around the world. In Brazil, different MMSE versions and many cut-off points have been used. A systematic review of papers indexed in Scielo was conducted in order to analyze use of the MMSE in Brazilian empirical studies with elderly people. To search for these texts, the complete name of the instrument and its abbreviation were used. A growth trend in the scientific production during the 1998 to 2013 period was observed. Eleven versions of the MMSE were identified and the Bertolucci et al. version was the most cited. Over half of the studies used schooling as the criteria to establish cut-off points. The studies were predominantly conducted using samples recruited from large cities in the Southeastern region and in the community. Despite the growing trend of research with the elderly using the MMSE, the psychometric properties of this scale of measurement have been the subject of little investigation. Despite the widespread use of the MMSE in Brazil, there is a lack of standardization and evidence of validity for this this scale of measurement.O Mini Exame do Estado Mental (MEEM) é o teste de rastreio cognitivo mais utilizado no mundo. No Brasil, diferentes versões e pontos de corte do MEEM têm sido usados. Para analisar seu uso em estudos empíricos brasileiros com idosos, efetuou-se uma revisão sistemática de artigos indexados na SciELO. Foram utilizados o nome completo do instrumento e sua abreviação para recuperar os textos. Observou-se uma tendência de crescimento da produção científica analisada, no período de 1998 a 2013. Foram mencionadas 11 versões do MEEM, destacando-se a de Bertolucci et al. Mais da metade das investigações fizeram uso da escolaridade como critério para estabelecer pontos de corte. Os estudos têm sido realizados predominantemente com amostras recrutadas em grandes cidades da região Sudeste e na comunidade. Não obstante a tendência de crescimento de pesquisas com idosos que utilizam o MEEM, as propriedades psicométricas dessa medida têm sido pouco investigadas. Apesar da ampla utilização do MEEM no Brasil, faltam padronização e evidências de validade para essa medida
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