1,721,024 research outputs found
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
Aprendizaje de redes regulatorias bacterianas a partir de algoritmos genéticos
No full textLa expresión genética está determinada por interacciones de tipo proteína-proteína entre diversas proteínas regulatorias y la(s) ARN polimerasa(s), e interacciones de estas con secuencias de ADN de los sitios promotores de los genes regulados [2]. Estas interacciones definen redes genéticas complejas cuyos diseños han motivado a los investigadores a utilizar herramientas matemáticas y computacionales para la construcción y posterior análisis de los diagramas de interacciones. Esta complejidad se ve incrementada por la cantidad de genes considerados en las redes y por el ruido existente en los datos disponibles. El desarrollo de modelos computacionales de redes genéticas posee una gran importancia dado que posibilita, entre otras aplicaciones, obtener modelos dinámicos de sistemas vivientes que facilita el descubrimiento y caracterización de blancos terapéuticos potenciales. No sólo la topología de una red es determinante de la dinámica en la expresión de los genes sino también los parámetros del modelo, problema de gran dimensionalidad para ser abordado con técnicas exhaustivas. A su vez, en distintos contextos dentro de la biología celular se plantea que las redes de interacción molecular dentro de las células deberían tener una robustez intrínseca a las variaciones de los parámetros que la definen. Actualmente existe un método que permite manejar estos problemas a través de un enfoque adaptativo. Para llevar a cabo esta tarea, este método utiliza una aproximación por búsqueda aleatoria para obtener las condiciones iniciales y parámetros del modelo, lo cual lo hace poco performante ya que la proporción de ejecuciones de una red en relación a las soluciones válidas es muy baja. Por otro lado, existe un conjunto de modelos computacionales que permiten la resolución de problemas en base a modelos de proceso evolutivo y que se los conoce genéricamente con el nombre de algoritmos evolutivos [1]. Dentro de ellos se encuentran los algoritmos genéticos, que son una técnica metaheurística para la solución de problemas de optimización y que se basan en una analogía de la teoría biológica de la evolución de las especies, utilizando esta idea para buscar una o más soluciones óptimas entre un conjunto de posibles soluciones. En el presente trabajo proponemos un método basado en dichos algoritmos con el objetivo de optimizar la obtención de condiciones iniciales para redes genéticas y de esa manera lograr soluciones válidas al problema planteado, en lo referente a validez biológica y robustez de las arquitecturas que se obtengan. Para probar este método se utilizó una red regulatoria que está formada por los sistemas de dos componentes PhoP/PhoQ y PmrAlPmrB, los cuales gobiernan la virulencia y la adaptación a medios de bajo Mg2 + y alto Fe +, respectivamente, en la bacteria Salmonella enterica serovar Typhimurium[8] [14]. El estudio del regulón PhoP constituye un desafío especial debido a la multiplicidad de blancos controlados por PhoP, y a la conectividad del sistema PhoPlPhoQ con otros sistemas de dos componentes, tales como PmrA/PmrB, reguladores transcripcionales y factores sigma alternativos de RNA polimerasa. Los resultados arrojados por nuestro método mostraron una altísima correlación entre estos y los valores obtenidos en experimentaciones biológicas, lo que demuestra que el método tiene una gran validez biológica. A esto se le agrega que el mecanismo de aprendizaje utilizado no necesita información extra para lograr su objetivo. Por otro lado, el método obtuvo una mayor proporción de resultados en relación a los obtenidos por el método basado en búsqueda aleatoria, con mejores puntajes (scores) numéricos. Finalmente, estas arquitecturas mostraron una gran robustez en cuanto a la configuración de los parámetros definidos.Gene express ion is determined by protein-protein interactions among several regulatory proteins and by RNA polymerase(s), and protein-ONA interactions of these molecules with ONA sequences in the promoters of regulated genes [2]. These interactions define complex genetic networks, whose designs have motivated researchers to use mathematical and computational tools for the construction and posterior analysis of a proposed network diagram. This complexity is increased by the number of genes considered in the networks and the amount of noise that exists in available data. The development of computational models of genetic networks has a tremendous importance since it allows, among other applications, to obtain dynamic models of living systems to facilitate discovery and characterization of potential therapeutic targets. The network topology is not the only determinant element in the dynamics of gene expression, but also are crucial the parameters of the model. Indeed, in different contexts of cellular biology it has been proposed that molecular interaction nets inside the cell should have an intrinsic robustness regarding the parameter variations that define them. Because of the extent of the search space of these parameters it is not viable to apply exhaustive techniques to study the possible configurations. Nowadays, there is a method that deals with those problems using an adaptative approach. In order to carry out this task this method uses a random search process to get initial conditions and parameters of the model. As a result of this approach this method has a low performance shown by the low ratio of valid solutions obtained and the total number of evaluations of models. On the other hand, there is a set of computational models that allows the resolution of certain problems based on evolutive process models which are known as evolutive algorithms [1]. Among this set we can find genetic algorithms which are a metaheuristic technique for the solution of optimization problems. They are based on an analogy of species evolution theory, using this idea in order to search for one or more optimal solutions among a set of possible ones. In this work we propose a method based on these algorithms with the aim of optimizing the capability to obtain initial conditions and parameters for genetic networks, focusing on their biological validity and the robustness ofthe obtained architecture. To test this method we used a regulatory networks which is formed by a system of two components PhoP/PhoQ and PmrA/PmrB, which govern virulence and the adaptation to low Mg2 + and high Fe3 + environments respectively, in the enteric bacteria Salmonella enterica serovar Typhimurium[8], [14]. The study of the PhoP regulon constitutes a special challenge due to the multiplicity of PhoP-controlled targets and the connectivity of the PhoP/PhoQ system with other two-component systems, such as PmrAlPmrB, transcriptional regulators, and alternative RNA polymerase sigma factors. The results obtained by the method described in this work showed a high correlation to the values collected in biological experimentations, validating the biological significance of our results. In addition, our method uses a learning approach which does not need extra information to reach its goal; and it obtained better numerical scores and better proportion of valid solutions than the random search approach. Finally, these architectures showed a great robustness regarding their parameters configuration.Fil: Santos, Marcelo Hugo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
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
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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