1,721,219 research outputs found
Estimativa da produção de sedimentos em bacias hidrográficas por meio do modelo de erosão USLE e do índice de transferência de sedimentos - SDR.
No full textA região norte-noroeste fluminense apresenta um processo erosivo extremamente acentuado nas áreas rurais em decorrência do uso e manejo inadequado dos solos. Constata-se o assoreamento e/ou desaparecimento de rios e a migração de nascentes, com o comprometimento da manutenção dos ecossistemas terrestres e aquáticos e da produção agropecuária. Neste contexto, este estudo teve como objetivo principal estimar a produção de sedimentos em duas bacias hidrográficas: Santa Maria e Cambiocó, utilizando o modelo preditivo de erosão (USLE) associado ao índice de transferência de sedimentos (SDR) incorporado ao próprio modelo, com o auxílio de Sistemas de Informação Geográficas (SIGs). Inicialmente elaborado para estimar perdas de solos em propriedades rurais com fins conservacionistas, a aplicação do Modelo Preditivo de erosão – USLE para estimar a produção de sedimentos em bacias hidrográficas se deu com a associação do índice de transferência de sedimentos (SDR) ao modelo. O procedimento consistiu na estimativa de perdas de solo por meio do modelo USLE para as duas bacias e, em seguida, na estimativa da produção de sedimentos nas duas bacias de estudo a partir do índice de transferência de sedimentos SDR. A estimativa da erosividade da precipitação foi efetuada a partir da relação entre as precipitações médias mensais e a anual utilizando a equação recomendada por Lombardi para as condições climáticas locais. A erodibilidade dos solos foi estimada pelo método indireto desenvolvido por Denardin (1990) com modificações sugeridas por Levy (1995), paras as condições de solos tropicais. No cálculo do fator topográfico, foram utilizadas três metodologias: Rocha et al, (1996), o programa USLE-2D implementadas no software IDRISI e uma proposta utilizando a equação proposta por Bertoni e Lombardi Neto (1980) utilizando o software ArcGIS A partir das variáveis de erosividade das chuvas, erodibilidade dos solos e fator topográfico foi estimado o Potencial Natural de Erosão (PNE). A perda de solo (A), em Mg.ha-1.ano-1 foi estimada a partir do PNE e dos parâmetros de uso, cobertura e de práticas conservacionistas (CP). Para demonstrar a intervenção do Projeto que vem buscando introduzir o plantio do tomate em curva de nível na região, foram adotados dois valores de CP, ou seja, um valor de CP igual a 1 (um), indicando nenhuma adoção de práticas conservacionistas e um valor de CP igual a 0,5 para avaliar o efeito desta prática no controle do processo erosivo nas áreas com tomate. O cálculo do SDR foi efetuado pelo método proposto por Wischmeier e Smith (1978), o qual relaciona o SDR com a área da bacia hidrográfica. O segundo método foi elaborado pelo Forest Service (1980) que busca incorporar características da bacia hidrográfica que afetam a produção de sedimentos. Na estimativa do escoamento superficial foi utilizado o Método do Balanço de Água na Superfície do Solo (Pruski et al. 1997a). Este método busca associar ao Método do Número de Curvas (USDA_SCS, 1972, 1973), fundamentos físicos já consagrados na engenharia para estimar o volume de escoamento superficial em localidades em que a relação entre intensidade, duração e freqüência da precipitação é conhecida. As principais críticas à Equação de Perdas de Solos referem-se ao seu empirismo e ao fato de se limitar a estimar apenas as perdas médias anuais de solo. Quanto ao índice SDR, embora o Modelo proposto pelo Serviço Florestal Americano (Forest Service, 1980) possa ser considerado como um avanço ao método proposto por Wischmeier e Smith (1978), por incorporar na análise da produção de sedimentos aspectos fundamentais da bacia, isto ainda é feito de forma subjetiva. No entanto, muito embora a análise quantitativa da produção de sedimentos necessite de maiores investigações e da validação dos valores estimados, o uso de modelos preditivos de erosão surge como uma ferramenta útil para estimar a produção de sedimentos em bacias hidrográficas, pois permite uma análise qualitativa das áreas de potencial erosivo sendo úteis no gerenciamento das ações mitigadoras do processo erosivo.Dissertação (Mestrado em Geografia) - Instituto de Geografia, Universidade Federal do Rio de Janeiro, Rio de Janeiro. Orientador: Nelson Ferreira Fernandes, UFRJ; Coorientador: José Ronaldo de Macedo, CNPS
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
No full textWe 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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