1,720,961 research outputs found
Determination of Cd, Cu and Zn in Dystrophic Red submitted to different systems in the region of Chapadões-MS
No full textA soja é uma cultura de grande importância comercial na produção agrícola da região Centro Oeste. Avanços tecnológicos permitiram o contínuo aumento do rendimento dessa lavoura, contudo, associado ao crescente emprego de agrotóxicos e fertilizantes, os quais podem contribuir como fonte de metais disponíveis na camada superficial do solo. Desenvolveu-se, portanto na UFMS/CPCS um estudo experimental para avaliação da produtividade da soja e dos seguintes atributos químicos do solo: Matéria Orgânica (MO), pH, Capacidade de Troca Catiônica (CTC) e para os metais Cádmio, Cobre e Zinco determinou-se os teores totais e a fração solúvel em um Latossolo Vermelho distrófico, textura média. Utilizou-se no delineamento experimental blocos casualizados em parcelas sub subsubdivididas. As parcelas constituíram-se pelos três tipos de preparo do solo: convencional-PC (grade aradora e grade niveladora), mínimo-PM (grade niveladora) e semeadura direta-SD. As subparcelas foram constituídas pelas plantas de cobertura de solo: milheto e pousio (inverno). As sub-subparcelas foram as 3 camadas (0-0,10; 0,10-0,20 e 0,20-0,30 m) de solo coletado. Nos extratos totais do solo os metais Cu e Zn concentraram-se nas camadas superiores (0-0,10 e 0,10-0,20 m) independentemente dos sistemas de preparo. A avaliação do sistema de manejo, em seu primeiro ano de implantação, não promoveu impactos sobre os atributos químicos (Matéria Orgânica, pH, teores totais e extratos solúveis de Cobre e Zinco) do solo analisado. O solo que tinha como cobertura o milheto e o pousio diferiram em relação ao teores de Zn total, sendo no solo com milheto determinou-se um menor teor total de Zn. Observou-se que a produtividade foi influenciada pelo preparo do solo, com maior produção de grãos de soja na Semeadura Direta. A Capacidade de Troca Catiônica do solo foi maior nos Preparo Convencional e Preparo Mínimo do solo. O solo que teve o milheto como cobertura, apresentou menor teor solúvel do elemento Cádmio no solo.ABSTRACT - Soybean is a crop of great commercial importance in the agricultural production of the Midwest region. Technological advances have enabled the continuous increase in the yield of this crop, however, associated with the increasing use of pesticides and fertilizers, which can contribute as a source of metals available in the topsoil. Developed, so the UFMS / CPCS an experimental study to evaluate soybean yield and soil chemical properties following: Organic Matter (MO), pH, cation exchange capacity (CTC) and for cadmium, copper and zinc metals we determined the total concentration and the soluble fraction in an Oxisol, medium texture. Was used in a randomized block experimental design in sub split plots. The plots were constituted by three types of tillage: Conventional PC (harrow and harrowing), minimum PM (harrowing) and SD direct-seeding. The subplots were established by plants cover crops: millet and fallow (winter). The sub-subplots were 3 layers (0-0.10, 0.10-0.20 and 0.20-0.30 m) of soil collected. In total extracts of soil Cu and Zn were concentrated in the upper layers (0-0.10 and 0.10-0.20 m) regardless of tillage systems. A review of the management system in its first year of implementation, not promoted impacts on chemical properties (Organic matter, pH, total content and soluble extracts of Copper and Zinc) in the analyzed soil. The soil that was to cover the millet and fallow differ regarding levels of total Zn, being on the ground with millet was determined a lower total Zn content. It was observed that productivity was influenced by tillage, with increased production of soybeans in direct sowing. The cation exchange capacity of the soil was higher in Conventional Tillage and Minimum Tillage soil. The soil had millet as cover showed lower soluble content of the element Cadmium in soil
Alterações químicas em neossolo quartzarênico e produtividade da urochloa brizantha cv. brs piatã tratado com cama de peru
Get PDFA cama aviária resultante do sistema de produção avícola vem sendo estudada, na produção agrícola e em pastagens, como alternativa de adubação orgânica e para correção de solos. Objetivou-se neste trabalho avaliar diferentes doses de adubação orgânica (cama de perú) quanto a sua capacidade de alterar os atributos químicos do solo e seu efeito na produtividade da pastagem de Urochloa brizantha cv. Brs Piatã em neossolo quartzarênico. O experimento foi realizado na Fazenda Vale Verde no Município de Mineiros (GO). O delineamento experimental utilizado foi em blocos casualizados, com cinco tratamentos, constituído por T1 (Testemunha, ausência de adubação orgânica) e quatro dosagens de cama de peru no solo: T2 (4000 kg ha-1), T3 (8.000 kg ha-1), T4 (12.000 kg ha-1) e T5 (16.000 kg ha-1). Realizou-se o estudo por meio das análises químicas obtidas nas quatro camadas (0,0 a 0,10, 0,10 a 0,20, 0,20 a 0,30 e 0,30 a 0,40 m) de profundidade de solo, e cinco tempos de avaliação (0, 60, 120, 180 e 240 dias), sendo a medida de produtividade da urochloa avaliada em quatro cortes, compreendendo duas estações climáticas, a estação seca e a estação chuvosa, distribuídos em dois períodos climáticos, ou seja, após 60 dias e 120 dias do plantio (período das águas) e 180 e 240 dias do plantio (período da seca). As variáveis analisadas nos experimentos foram: produção de matéria seca (MS) e as análises dos seguintes atributos químicos do solo: pH em CaCl2, Matéria Orgânica (MO), Cálcio (Ca), Magnésio (Mg), Potássio (K), Fósforo (P), Alumínio (Al), Cobre (Cu) e Zinco (Zn). As coletas dos dados foram feitas a cada 60 dias durante oito meses, totalizando quatro coletas. Os dados foram retirados da área útil de cada parcela (36 m2). Os tratamentos resultaram em melhoria na fertilidade do neossolo quartzârenico, pois promoveram o aumento do pH, da matéria orgânica, dos macronutrientes primários P e K, dos macronutrientes secundários Ca e Mg, e pela diminuição do teor de Al. Sendo os melhores resultados encontrados advindos dos aumentos de dosagem da cama aviária e encontrados na camada 0,0 a 0,10 m de profundidade do solo. Em relação aos micronutrientes avaliados pode-se inferir que o Cu e o Zn apresentaram baixas concentrações nas camadas de maiores profundidades. Observou-se no período analisado que o Cu foi mais móvel na camada de 0,0 a 0,10 m e que o Zn apresentou maiores concentrações acompanhando o incremento das doses. Os tratamentos proporcionaram aumento na produção de matéria seca da Urochloa brizanta cv. BRS Piãta em função da maior disponibilidade de água (período chuvoso), contribuindo para a maior capacidade produtiva alcançada da pastagem na dose de (16.000 kg ha-1).ABSTRACT - The resulting poultry manure from poultry production system has been studied in agricultural production and pasture, as an alternative to organic fertilizers and soil correction. The aim of this study was to evaluate different doses of organic fertilization (perú bed) and its ability to change the soil chemical properties and its effect on productivity of Urochloa brizantha pasture. Br Piata in Quartzipsamment. The experiment was conducted at Fazenda Vale Verde in the municipality of Mineiros (GO). The experimental design was randomized blocks, with five treatments, consisting of T1 (control, no organic fertilizer) and four turkey litter dosages in soil: T2 (4000 kg ha-1), T3 (8,000 kg ha-1), T4 (12,000 kg ha-1) and T5 (16,000 kg ha-1). The study was carried out by means of chemical analysis obtained in four layers (from 0.0 to 0.10, 0.10 0.20, 0.20 to 0.30 and 0.30 to 0.40 m) deep solo, five times of evaluation (0, 60, 120, 180 and 240 days), the Urochloa productivity measure evaluated in four sections, comprising two seasons, the dry season and the rainy season, over two periods climate, i.e., after 60 days and 120 days after planting (rainy season) and 180 and 240 days after planting (dry season).
The variables analyzed in the experiments were: production of dry matter (DM) and analysis of the following for soil pH in CaCl2, organic matter (OM), calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al), copper (Cu) and zinc (Zn). The collected data were made every 60 days for eight months, totaling four collections. Data were taken from the floor area of each plot (36 m2). The treatments resulted in improved fertility Psament as promoted increased pH, organic matter, primary macronutrients P and K, secondary macronutrients Ca and Mg, and by decreasing the Al content. Being the best results found arising of the poultry manure dosage increases and found the layer from 0.0 to 0.10 m soil depth. Regarding micronutrient can be inferred that Cu and Zn present in low concentrations from deeper layers. It was observed during the study period that Cu was more mobile in the layer 0.0 to 0.10 m and Zn concentrations were higher following the increase in dose. The treatments resulted in increased dry matter production of Urochloa brizantha cv. BRS Piata due to the greater availability of water (rainy season), contributing to greater production capacity achieved in the pasture dose (16,000 kg ha-1)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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