2,081 research outputs found

    Imazethapyr: red rice control and resistance, and environmental fate

    Get PDF
    Imazethapyr was recently approved for use in rice, but limited information is available regarding its efficacy, environmental fate or potential red rice resistance. Therefore, experiments were conducted to 1) determine the effect of flooding time, and stage of imazethapyr application in red rice control, 2) assess the acetolactate synthase resistance to imazethapyr on red rice ecotypes, 3) determine the relative photolysis of imazethapyr, and 4) determine the effect of soil and moisture on imazethapyr adsorption and availability. When imazethapyr was applied in sequential application of PRE followed by a POST application, to achieve >95% red rice control, flood needed to be established within 14 DAT when imazethapyr was applied EPOST, and 7 DAT when imazethapyr was applied LPOST. Delaying the flood up to 21 DAT reduced rice grain yield for both EPOST and LPOST application timings. Based on enzymatic activity, the mean I50 values were 1.5, 1.1, 1.5, 1.6, 20.8, and 590.6 mM of imazethapyr, respectively, for LA 5, MS 5, TX 4, ??Cypress??, ??CL-121??, and ??CL-161??. CL-161 was 32 times more resistant than CL-121, and at least 420 times more resistant than the average of the red rice ecotypes and ??Cypress??. Results from the ALS assay showed that red rice ecotypes and Cypress had high susceptibility to imazethapyr when compared with the tolerant CL-121 and the resistant CL-161. Measurable enzymatic tolerance to ALS-inhibiting herbicides has not yet developed in these red rice ecotypes. Imazethapyr quantum yield (fI ) was 0.023 ?? 0.002 while the hydroxyl radical rate constant ( I OH k?? ) was 2.8 ?? 0.44 x 1013 M-1 h-1. These results show that imazethapyr is susceptible to both direct and indirect photolysis. The results also show that imazethapyr photolysis in paddy water will be affected by turbidity due to its impact on the availability of sunlight to drive direct and indirect photolysis reactions. Imazethapyr was more available and more concentrated in sandy soil. With higher amounts of water in soil there was greater amount of imazethapyr in soil solution and a lower concentration of herbicide due to dilution. The double centrifuge method provided a better estimate of plant available herbicide

    Monitoramento de herbicidas em dois rios brasileiros durante o período de cultivo do arroz

    Get PDF
    No cultivo de arroz irrigado a possibilidade de contaminação dos mananciais hídricos é ampliada pelas características peculiares das áreas e do sistema de produção. Um estudo de monitoramento foi conduzido durante três anos (2000 a 2003), nos rios Vacacaí e Vacacaí-Mirim, localizados no Estado do Rio Grande do Sul, Brasil, buscando quantificar os herbicidas clomazone, propanil e quinclorac durante o período de cultivo do arroz. As amostras de água foram coletadas em vários locais em cada rio. Os locais de coleta foram selecionados pela importância em termos da captação da água de drenagem. As amostras foram analisadas por HPLC-UV. Herbicidas foram detectados nas águas dos rios durante no período de cultivo do arroz. Foi detectada a presença de pelo menos um herbicida em 41% das amostras no rio Vacacaí e 33% das amostras no rio Vacacaí-Mirim. O herbicida clomazone, foi detectado com maior freqüência nos dois rios. A quantidade de herbicida nas águas dos rios foi dependente do regime de chuva. A contaminação das águas dos rios pelos herbicidas utilizados no arroz provavelemente é decorrente do manejo de água adotado na região. A manutenção de áreas inundadas propicia a contaminação do ambiente por herbicidas. Para reduzir o risco de contaminação ambiental faz-se necessário à adoção de medidas que evitem a saída e liberação da água com resíduo das áreas de cultivo, mantendo-a na lavoura durante o tempo suficente para a redução da concentração do herbicida. A probabilidade de extravasamento pode ser reduzida com a melhor construção das taipas-ronda.Irrigated rice production can involve environmental contamination with pesticides due to the proximity of the fields to rivers and to management problems. During three years (2000 to 2003) the rice herbicides clomazone, propanil and quinclorac were quantified in water during the rice growing season, in the Vacacaí and Vacacaí-Mirim Rivers, located in Rio Grande do Sul (RS) State, Brazil. Water samples were taken at several locations in each river, selected by their importance in terms of rice drainage area. The samples were analyzed by HPLC-UV. At least one herbicide was detected in 41% of the samples from the Vacacaí River and 33% from the Vacacaí-Mirim River. The most frequent herbicide in both rivers and in each year was clomazone. The amount of herbicides in the river water was dependent on the rainfall regime. River water contamination by rice herbicides is probably caused by the rice water management used in the fields. The maintenance of flooded areas makes herbicides prone to contaminate the environment. To reduce the environmental contamination risk it is necessary to adopt measures to avoid overflow of flooded rice fields, keeping paddy water in the field for time enough to reduce the herbicide concentration before its release and enhancing the quality of the levees to reduce the probability of paddy rice overflow

    AVALIAÇÃO DE IMPACTOS SOBRE O CONHECIMENTO, CAPACITAÇÃO E POLÍTICO-INSTITUCIONAL DA PESQUISA GERADA PELA EMBRAPA

    Get PDF
    Este trabalho apresenta a experiência da Empresa Brasileira de Pesquisa Agropecuária - Embrapa na avaliação de impactos sobre o conhecimento, capacitação e político-institucional. O trabalho descreve a metodologia utilizada tomando como referência uma revisão bibliográfica sobre o tema e análisa documentos institucionais recentes e relatórios de avaliação disponibilizados pelas Unidades Descentralizadas da Embrapa. A metodologia utilizada para avaliação de impactos desta natureza é baseada na dimensão “capacitação” do método ESAC, criado pelo GEOPI/Unicamp. A Embrapa tem direcionado esforços no sentido de aprimorar a metodologia de avaliação de impactos sobre o conhecimento, capacitação e polítíco-institucional por considerar que os benefícios gerados pelas unidades de temas básicos da empresa, geram, principalmente benefícios intangíveis, que dificilmente podem ser medidos e demonstrados a partir das metodologias de avaliação tradicionais. Anualmente são avaliadas mais uma centena de tecnologias a partir da metodologia. Os resultados apontaram a eficiência do método para avaliar os impactos sobre o conhecimento, capacitação e político-institucional de tecnologias geradas também pelas unidades de pesquisa de produtos e agroflorestal ou agropecuária nas ecorregiões brasileiras. Um produto importante desta avaliação foi a incorporação da necessidade de avaliar os impactos da pesquisa da Embrapa em um enfoque multidimensional, já que a Empresa possui ainda uma longa experiência na avaliação de impactos econômicos, sociais e ambientais.---------------------------------------------This work presents the experience of the Brazilian Agricultural Research Corporation - Embrapa in the evaluation of impacts on the knowledge, qualification and institutional-politician. The work describes the methodology used taking as reference a bibliographical revision on the subject and analyzes recent institutional documents and reports of evaluation disponibilizados by the Decentralized Units of the Embrapa. The methodology used for evaluation of impacts of this nature is based on the dimension “qualification” of method ESAC, created for the GEOPI/Unicamp. The Embrapa has directed efforts in the direction to improve the methodology of evaluation of impacts on the knowledge, qualification and politician-institucional for considering that the benefits generated for the units of basic investigation of the company, generates, mainly intangible benefits, that hardly can be measured and be demonstrated from the traditional methodologies of evaluation. Annually they are evaluated plus a hundred of technologies from the methodology. The results had pointed the efficiency of the method to evaluate the impacts on the knowledge, qualification and institutional-politician of technologies also generated for the units of research of products and agricultural in the Brazil. An important product of of this evaluation was the incorporation of the necessity to evaluate the impacts of the research of the Embrapa in a another approach, since the Company still possesss a long experience in the evaluation of economic impacts, social and environment.Metodologia, Avaliação de impactos, Conhecimento, Methodology, evaluation of impacts, knowledge, Research and Development/Tech Change/Emerging Technologies,

    EFEITO DA APLICAÇÃO DE HERBICIDAS SUPOSTAMENTE ANTAGÔNICOS SOBRE PLANTAS DE ARROZ SUSCETÍVEIS A INIBIDORES DA ENZIMA ACCASE

    Get PDF
    The control of weedy rice has been widely studied in weed science. However, gene flow from Clearfield rice (CL) to weedy rice has damaged the efficiency of the CL production system. A new rice crop that is resistant to ACCase inhibitor herbicides will be launched in the next year on the market, representing another tool for managing weedy rice in irrigated rice crops. In addition to using this tool, there is a need to increase the spectrum of herbicide treatments to control the diversity of weed species in irrigated rice crops. This study aimed to elucidate the effect of latifolicidal herbicides on the graminicide action of quizalofop on cultivated rice as an indicator plant in the simulation of weedy rice. An experiment was carried out in a greenhouse at the Epagri – Experimental Station of Itajaí, Santa Catarina, Brazil. There was a reduction in the efficiency of rice control for all evaluated doses of quizalofop associated with 2,4-D.O controle do arroz-daninho tem sido foco de pesquisas na área de herbologia. Contudo, a ocorrência de fluxo gênico do arroz Clearfield (CL) para a espécie daninha tem resultado em perda na eficiencia do sistema de produção CL. Uma nova cultivar de arroz, resistente a herbicidas inibidores da ACCase, será lançada no mercado e se constitui em mais uma ferramenta para o manejo do arroz-daninho em lavouras de arroz irrigado. Aliada a essa ferramenta, existe a necessidade de aumento no espectro dos tratamentos herbicidas para o controle da diversidade de espécies de plantas daninhas infestantes nas lavouras de arroz irirgado. O objetivo deste estudo foi elucidar o efeito de herbicidas latifolicidas na ação graminicida do quizalofop sobre o arroz cultivado como planta indicadora na simulação de arroz-daninho. Foi realizado um experimento, em casa de vegetação na Epagri-Estação Experimental de Itajaí (SC). Os resultados obtidos indicam que houve redução da eficiência de controle do arroz em todas as doses avaliadas das associações de quizalofop com 2,4-D

    Rapid reduction of herbicide susceptibility in junglerice by recurrent selection with sublethal dose of herbicides and heat stress

    Get PDF
    Global climate change, specifically rising temperature, can alter the molecular physiology of weedy plants. These changes affect herbicide efficacy and weed management. This research aimed to investigate the combined effect of heat stress (HS) and sublethal doses of herbicides (four active ingredients) on adaptive gene expression and efficacy of herbicide on Echinochloa colona (L.) Link (junglerice). Three factors were evaluated; factor A was E. colona generation (G0-original population from susceptible standard; G1 and G2 were progenies of recurrent selection), factor B was herbicide treatment (florpyrauxifen-benzyl, glufosinate-ammonium, imazethapyr, quinclorac and nontreated check) and factor C was HS (30 and 45 ◦C). The herbicides were applied at 0.125× the recommended dose. Recurrent exposure to HS, combined with sublethal doses of herbicides, favors the selection of plants less susceptible to the herbicide. Upregulation of defense (antioxidant) genes (APX: Ascorbate peroxidase), herbicide detoxification genes (CYP450 family: Cytochrome P450), stress acclimation genes (HSP: Heat shock protein, TPP: Trehalose phosphate phosphatase and TPS: Trehalose phosphate synthase) and genes related to herbicide conjugation (UGT: UDP Glucosyltransferase) was significant. The positive regulation of these genes may promote increased tolerance of E. colona to these herbicides

    Volatility of clomazone formulations under field conditions

    Get PDF
    A volatilização representa um processo importante no deslocamento de agrotóxicos para o ambiente. As características físico-químicas da molécula do clomazone indicam potencial de volatilidade. O presente estudo tem o objetivo de avaliar a volatilização de três formulações de clomazone em condições de campo por meio de plantas bioindicadoras com o uso de tuneis de vento. Túneis de polietileno transparente foram alocados sobre a cultura do sorgo (Sorghum bicolor), onde as formulações do herbicida foram aplicadas no centro destes. O experimento foi arranjado em parcelas subdivididas, com quatro repetições. As parcelas foram representadas pelas diferentes formulações do herbicida: Gamit 360 CS®, Gamit 500 EC® e Gamit Star®, além da testemunha sem aplicação de herbicida. As subparcelas foram caracterizadas pelas distâncias em relação ao local de aplicação: 1, 2, 3, 4, 5, 6 metros a favor e contra a direção predominante do vento. Foi então realizada avaliação de toxicidade em diferentes dias nas plantas de sorgo após a aplicação dos herbicidas. Os sintomas de todas as formulações foram mais intensos nas plantas próximas do local da aplicação, sendo esses ainda mais acentuados ao longo da linha onde a direção do vento foi predominante. No geral, independente da distância, o Gamit 360 CS® causou menor toxicidade a bioindicadora. Conclui-se que dentre as formulações avaliadas, Gamit 360 CS® apresenta menor volatilização e consequentemente menor é o risco de contaminações de culturas vizinhas e do ambiente. As outras duas formulações possuem maior potencial de volatilização.Volatilization plays an important role in the process of herbicide dispersion in the environment. The physicochemical characteristics of the clomazone molecule indicate its volatility potential. The present study aimed to evaluate the volatilization rate of three clomazone formulations under field conditions using indicator plants and wind tunnels. Transparent polyethylene tunnels were placed on a sorghum (Sorghum bicolor) field parallel to the prevalent wind direction, and the herbicide formulations were applied in plastic trays containing 10 kg of sieved soil and placed at the center of the tunnel. The experiment was arranged in a slip-plot design with four replications. The main plots were represented by different formulations of the herbicides: Gamit 360 CS®, Gamit 500 EC® and Gamit Star®, and control plots without herbicide application. The sub-plots represented the distances from the application site: 1, 2, 3, 4, 5, 6 meters. Herbicide injury in sorghum was then assessed at different days after application. The symptoms of all formulations were more intense in the plants that were closer to the application site, and were even more severe in the prevailing wind direction. In general, regardless of the application distance, Gamit 360 CS® caused less injury to the sorghum. It is concluded that among the formulations assessed, Gamit 360 CS® has a lower volatilization rate and, consequently, lower contamination risk of neighboring crops and the environment. The other two formulations have higher volatility potential

    Ocorrência de Leptospira spp. e fatores associados à infecção em equinos de contingente militar no estado do Rio Grande do Sul, Brasil

    Get PDF
    The seroprevalence of Leptospira spp. and infection risk factors were investigated in horses from a military contingent in the Rio Grande do Sul State, Brazil. A total of 446 horses were evaluated and categorized into 309 mares, 11 stallions, and 126 horses with an average age of three years. To determine seroprevalence, serum samples from all horses were submitted to the microscopic agglutination test against 12 serovars belonging to nine serogroups, usually circulating in equine populations. To investigate the possible risk factors of infection by Leptospira spp., questionnaires were applied in that military unit. The seroprevalence in the horses with an average age of 3 years, mares, and stallions were 57.94% (73/126), 54.05% (165/309), and 45.45% (5/11), respectively. The main risk factors identified were contact with different water sources, the presence of rodents, and contact with wild and domestic animals. The high seroprevalence of anti‑Leptospira spp. antibodies may be associated with the presence of these risk factors. Therefore, the exposure of horses to possible reservoirs of Leptospira spp. should be minimized. Also, the immunoprophylaxis protocol should be reviewed and a shorter interval between vaccinations adopted to control leptospirosis in this herd. A soroprevalência de Leptospira spp. e os fatores de risco para infecção foram investigados em cavalos de um contingente militar no Rio Grande do Sul, Brasil. Um total de 446 cavalos foram avaliados e categorizados em 309 éguas, 11 garanhões e 126 cavalos com idade média de três anos. Para determinação da soroprevalência, amostras de soro de todos os equinos foram submetidas ao teste de aglutinação microscópica contra 12 sorovares pertencentes a nove sorogrupos, normalmente circulantes em populações equinas. Para investigar os possíveis fatores de risco da infecção por Leptospira spp., foi aplicado um questionário naquela unidade militar. A soroprevalência nos cavalos com idade média de três anos, éguas e garanhões foi de 57,94% (73/126), 54,05% (165/309) e 45,45% (5/11), respectivamente. Os principais fatores de risco identificados foram o contato com diferentes fontes de água, a presença de roedores e o contato com animais silvestres e domésticos. A alta soroprevalência de anticorpos anti-Leptospira spp. pode estar associada à presença desses fatores de risco. Portanto, a exposição destes equinos aos possíveis reservatórios de Leptospira spp. deve ser minimizada. Além disso, o protocolo de imunoprofilaxia deve ser revisto e, possivelmente, um menor intervalo entre as vacinas deve ser adotado para o controle da leptospirose neste plantel

    Systems chemo-biology analysis of DNA damage response and cell cycle effects induced by coal exposure

    Get PDF
    Cell cycle alterations are among the principle hallmarks of cancer. Consequently, the study of cell cycle regulators has emerged as an important topic in cancer research, particularly in relation to environmental exposure. Particulate matter and coal dust around coal mines have the potential to induce cell cycle alterations. Therefore, in the present study, we performed chemical analyses to identify the main compounds present in two mineral coal samples from Colombian mines and performed systems chemo-biology analysis to elucidate the interactions between these chemical compounds and proteins associated with the cell cycle. Our results highlight the role of oxidative stress generated by the exposure to the residues of coal extraction, such as major inorganic oxides (MIOs), inorganic elements (IEs) and polycyclic aromatic hydrocarbons (PAH) on DNA damage and alterations in the progression of the cell cycle (blockage and/or delay), as well as structural dysfunction in several proteins. In particular, IEs such as Cr, Ni, and S and PAHs such as benzo[a]pyrene may have influential roles in the regulation of the cell cycle through DNA damage and oxidative stress. In this process, cyclins, cyclin-dependent kinases, zinc finger proteins such as TP53, and protein kinases may play a central role

    PROTOCOLOS DE PREVENÇÃO E TRATAMENTO DE ÚLCERAS POR PRESSÃO: ANÁLISE DA PRODUÇÃO BRASILEIRA

    Get PDF
    Objective: To analyze the production of theses and dissertations in nursing about the pressure ulcer prevention and treatment protocols. Method: This is a narrative review of of literature. The search data was in June 2013, on the  theses and dissertations database of Improvement Coordination of Personal Higher Education starting with the question: "What is the academic production from dissertations and theses in nursing on pressure ulcer prevention and treatment protocols or measures? ". Result: The corpus of the research was composed of six studies approaching the treatment and prevention protocols for pressure ulcers were selected. The Braden Scale was the most used predictive scale for pressure ulcer risk in the protocols. The studies assessed the treatment and preventive actions taken by health staff and the knowledge about pressure ulcers. Conclusion: The improvement and expansion of the health professionals’ clinical skills are necessary for the process of pressure ulcers risks assessment through the protocols.  Descriptors: Nursing; Pressure Ulcer; Protocols.Objetivo: analisar as produção de teses e dissertações em enfermagem referentes a protocolos de prevenção e tratamento de Úlcera por Pressão. Metodologia: Trata-se de um estudo de revisão narrativa de literatura. A busca de dados aconteceu em junho de 2013, no banco de teses e dissertações da Coordenação de Aperfeiçoamento de Pessoal Nível Superior, a partir da questão: “Qual a produção acadêmica a partir de teses e dissertações na área da enfermagem sobre protocolos ou medidas de prevenção e tratamento de Úlcera por Pressão?”. Resultado: O corpus da pesquisa foi composto por seis trabalhos com destaque para prevenção a partir da escala preditiva de risco de Ulcera por Pressão, Escala de Braden, ações preventivas e de tratamento utilizadas pela equipe de enfermagem e o conhecimento sobre Úlceras por Pressão. Conclusão: É necessário o aperfeiçoamento e ampliação da habilidade clínica dos profissionais de saúde no processo de avaliação de risco para Úlcera por Pressão através de protocolos. Descritores: Enfermagem; Úlcera por Pressão; Protocolo
    corecore