1,720,953 research outputs found
Evaluation of the agronomic potential of organic fertilizer derived from macrophyte plants in maize (Zea mays L.) cultivation
No full textA erosão do solo e a contaminação dos recursos hídricos por nutrientes potencializam o processo de eutrofização, favorecem o crescimento de plantas macrófitas que impactam a geração de energia elétrica em reservatórios hídricos. A remoção dessas plantas próximo às margens das represas são passivos ambientais que demandam um correto destino. Porém, a busca de práticas agrícolas sustentáveis com a adoção de fontes alternativas para a produção de fertilizantes orgânicos permite explorar essas plantas como fonte orgânica devido ao seu potencial de acumular, remover nutrientes dos reservatórios e reduzir a eutrofização. Assim, este estudo teve como objetivo avaliar o uso de plantas macrófitas na produção de fertilizante orgânico e sua capacidade de suprir as necessidades nutricionais no desenvolvimento inicial do milho. O composto produzido foi caracterizado conforme parâmetros estabelecidos pela Instrução Normativa n° 61/2020 para fertilizantes orgânicos e pela Instrução Normativa SDA n° 7/2016 quanto aos elementos potencialmente tóxicos. Em casa-de-vegetação avaliou-se o potencial agronômico do fertilizante orgânico no estabelecimento da cultura do milho em dois tipos de solo (franco-arenoso e argiloso), seis doses de composto orgânico de plantas macrófitas (CMA) (0, 2, 4, 6, 8 e 10 g dm-3), além de um controle positivo com fertilizante mineral equivalente ao nitrogênio, fósforo e potássio da maior dose do fertilizante orgânico, totalizando 14 tratamentos em delineamento em blocos casualizados. Os atributos químicos do solo, atividades das enzimas arilsulfatase, β-glucosidase, fosfatase ácida, altura, diâmetro, área foliar, massa seca da raiz (MSR), massa seca da parte aérea (MSPA), massa seca total (MST), acúmulo de nutrientes na raiz, parte aérea e total, eficiência de absorção e recuperação dos nutrientes foram avaliados após 45 dias da semeadura (estádio fenológico do milho V9). A qualidade do composto orgânico foi avaliada por meio da respiração basal do solo (RBS) e lixiviação de nutrientes. No experimento de RBS, o delineamento foi inteiramente casualizado, com seis tratamentos e quatro repetições, considerando duas fontes orgânicas: um controle positivo de composto de lodo de esgoto (CLE), além de solo sem fertilização (CT). A liberação de CO2 foi quantificada aos 1, 2, 4, 7, 14, 21, 28, 35, 42, 49, 56 e 63 dias após a incubação. No experimento de lixiviação, conduzido em colunas, foram avaliados nitrato (NO3-), amônio (NH4+) e potássio (K+) aos 1, 7, 21, 35, 49 e 63 dias. A caracterização do CMA apresentou pH 7,7, C% 23,92, N% 1,23, C/N 19, U% 4,8, CTC 519 mmolc kg-1 e CE 5,18 µS cm-1, o que atendeu aos requisitos das legislações para produção e comercialização de fertilizantes orgânicos. Os teores de arsênio, cádmio, chumbo, cromo, mercúrio, níquel e selênio apresentaram valores inferiores aos estabelecidos na Instrução Normativa SDA n° 27/2016. No solo o fornecimento de doses crescentes de CMA elevou os atributos químicos como a CTC, SB, V%, P, K, Ca, Mg e Mn em ambos os solos, MOS no solo argiloso e S no solo arenoso. Os valores de H+Al e Cu reduziram nos solos argiloso e franco-arenoso respectivamente. Já para a atividade enzimática, no solo franco-arenoso observou aumento da atividade β-glucosidase e fosfatase e redução da arilsulfatase, enquanto no solo argiloso houve redução da fosfatase. No desenvolvimento do milho houve incremento significativo para altura, diâmetro, MSPA, MSR e MST em razão da dose do CMA. Na dose de 10 g dm-3 de CMA, a MST foi de 15,9 gramas e 12,6 gramas em solos franco-arenoso e argiloso, equivalente a 20% e 31% da MST do fertilizante mineral. O aumento no acúmulo total dos nutrientes nas plantas de milho foi significativo nos solos franco-arenoso e argiloso em razão das doses de CMA, com exceção ao Mg, S e Cu no solo franco-arenoso. A eficiência de absorção e recuperação para o P aumentou em razão da dose de CMA. Para o N houve redução da eficiência de absorção no solo argiloso, enquanto a recuperação de N não alterou. Para o K, houve maior eficiência de absorção em solo franco-arenoso e recuperação em solo argiloso, porém a recuperação de K foi menor em solo franco-arenoso. A lixiviação acumulada de NO3- e NH4+ foi menor com CMA em comparação ao CT e não diferiu em comparação ao CLE em ambos os solos. Para o K os maiores valores de lixiviação foram observados para o fertilizante mineral (FM). O CMA apresentou valores de lixiviação da ordem de 7,74 e 8,03 mg coluna-1nos solos franco-arenoso e argiloso, respectivamente, valores inferiores ao FM e superiores quando comparado com CLE. A RBS apresentou maiores valores acumulados para o CMA, quando comparado com CLE e solo sem fertilização. O CMA atendeu aos requisitos mínimos para ser caracterizado como fertilizante orgânico, assim como mostrou-se seguro quanto aos teores de elementos potencialmente tóxicos e baixo risco de lixiviação para NO3-. Apesar de ser observado melhorias nas características químicas do solo e acúmulo de nutrientes na planta, o potencial agronômico do composto orgânico foi limitado quando comparado com fertilizante mineral.Soil erosion and water contamination by nutrients enhance the process of eutrophication, favoring the growth of macrophyte plants that affect electricity generation in water reservoirs. The removal of these plants near reservoir margins creates environmental liabilities that require proper disposal. However, the pursuit of sustainable agricultural practices, including the use of alternative sources for the production of organic fertilizers, allows the exploitation of these plants as organic sources due to their potential to accumulate and remove nutrients from reservoirs and reduce eutrophication. Thus, this study aimed to evaluate the use of macrophyte plants in the production of organic fertilizer and their capacity to meet the nutritional requirements for the initial development of maize. The compost produced was characterized according to the parameters established by Normative Instruction N° 61/2020 for organic fertilizers and Normative Instruction SDA N° 7/2016 regarding potentially toxic elements. In a greenhouse, the agronomic potential of the organic fertilizer was evaluated for maize establishment in two soil types (sandy loam and clayey), with six doses of macrophyte-based organic compost (CMA) (0, 2, 4, 6, 8, and 10 g dm3), plus a positive control with mineral fertilizer equivalent to the nitrogen, phosphorus, and potassium content of the highest CMA dose, totaling 14 treatments in a randomized block design. Soil chemical attributes, enzyme activities (arylsulfatase, β-glucosidase, and acid phosphatase), plant height, stem diameter, leaf area, root dry mass (RDM), shoot dry mass (SDM), total dry mass (TDM), nutrient accumulation in root, shoot, and total plant, as well as nutrient uptake and recovery efficiency, were evaluated 45 days after sowing (V9 stage of maize). The compost quality was assessed by soil basal respiration (SBR) and nutrient leaching. In the SBR experiment, a completely randomized design was used with six treatments and four replications, considering two organic sources: a positive control with sewage sludge compost (SSC), and unfertilized soil (control - CT). CO2 release was measured at 1, 2, 4, 7, 14, 21, 28, 35, 42, 49, 56, and 63 days after incubation. In the leaching experiment, conducted in soil columns, nitrate (NO3), ammonium (NH4+), and potassium (K+) were evaluated at 1, 7, 21, 35, 49, and 63 days. The CMA characterization showed pH 7.7, C 23.92%, N 1.23%, C/N ratio 19, moisture 4.8%, CEC 519 mmolc kg-1, and EC 5.18 µS cm-1, meeting the legal requirements for the production and commercialization of organic fertilizers. The concentrations of arsenic, cadmium, lead, chromium, mercury, nickel, and selenium were below the limits established by Normative Instruction SDA N° 27/2016. Increasing CMA doses improved soil chemical attributes such as CEC, SB, base saturation (V%), P, K, Ca, Mg, and Mn in both soils, increased SOM in the clayey soil, and increased S in the sandy soil. H++Al and Cu levels decreased in the clayey and sandy loam soils, respectively. Enzymatic activity increased for β-glucosidase and phosphatase and decreased for arylsulfatase in the sandy loam soil, whereas phosphatase decreased in the clayey soil. Maize development showed significant increases in plant height, stem diameter, SDM, RDM, and TDM with increasing CMA doses. At 10 g dm-3 of CMA, the TDM was 15.9 g and 12.6 g in sandy loam and clayey soils, respectively, corresponding to 20% and 31% of the TDM obtained with mineral fertilizer. Total nutrient accumulation in maize increased significantly with CMA doses in both soils, except for Mg, S, and Cu in sandy loam. Phosphorus uptake and recovery efficiency increased with CMA dose. For nitrogen, uptake efficiency decreased in the clayey soil, while recovery remained unchanged. For potassium, uptake efficiency increased in sandy loam and recovery in clayey soil, but recovery decreased in sandy loam. Cumulative NO3- and NH4+ leaching was lower with CMA compared to the control and similar to SSC in both soils. For K, the highest leaching occurred with mineral fertilizer. CMA leaching values were 7.74 and 8.03 mg column-1 in sandy loam and clayey soils, respectivelylower than mineral fertilizer and higher than SSC. SBR was higher with CMA than with SSC and unfertilized soil. CMA met the minimum requirements to be classified as an organic fertilizer, showed safety regarding potentially toxic elements, and posed low nitrate leaching risk. Despite improvements in soil chemical attributes and plant nutrient accumulation, the agronomic potential of the organic compost was limited when compared to mineral fertilizer
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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