1,720,953 research outputs found
Observação experimental de transição de fase schools-shoals em peixe-zebra (Danio rerio)
Full text linkO comportamento coletivo da matéria ativa abrange uma ampla diversidade existente de seres vivos, podendo ser observado desde sistemas microscópicos até sistemas em grande escala. Tais sistemas são reconhecidos por seus indivíduos possuírem a capacidade de transformar energia interna ou do ambiente em movimento, caracterizando-se como sistemas físicos fora do equilíbrio. Um exemplo interessante de ser observado são grupos de peixes que fazem uso de trocas de informações entre os indivíduos que compõem o grupo para desenvolver benefícios energéticos, anti-predatórios e na busca por alimentos. A partir de decisões individuais, surgem padrões coletivos de estruturas em grande escala que podem ser analisados quantitativamente.
Porém, grande parte das definições que abordam o surgimento desses padrões, como as estruturas de schools e shoals, em grande maioria, são baseadas em critérios conceituais de sociabilidade. Neste trabalho, analisamos a transição de fase de grupos de peixe-zebra, através da variação da densidade. Para tanto, utilizamos câmeras de vídeo para capturar a posição e velocidade de peixes-zebra em um ambiente controlado. Consideramos um recipiente circular com 50 cm de diâmetro e uma lâmina d’água de 5 cm, realizamos o rastreamento das trajetórias dos peixes-zebra, variando o número de indivíduos N. Em seguida, investigamos as medidas de correlação dos peixes a partir das derivadas dos parâmetros de polarização, agregação e D-centroide utilizados neste trabalho, entre as séries temporais para grupos de N = 2,13 e 30 indivíduos, por meio do parâmetro q-gaussiano que serviram para reforçar transições de fase schools-shoals dos peixes-zebra. Assim, conseguimos caracterizar uma transição de fase entre os grupos de peixes através dos valores médios das séries temporais dos parâmetros de polarização, agregação e D-centroide, influenciada pela variação da densidade. Além disso, verificamos uma variação na correlação dos peixes através das flutuações destes mesmos parâmetros. Com os dados experimentais destes parâmetros, conseguimos quantificar o comportamento de school e shoal durante nossas análises.The collective behavior of active matter encompasses a wide diversity of existing living organisms, ranging from microscopic systems to large-scale systems. Such systems are recognized by their individuals having the ability to transform internal or environmental energy into movement, characterizing them as out-of-equilibrium physical systems. An interesting example to observe is groups of fish that make use of information exchange between the individuals that make up the group to develop energetic, anti-predatory, and food-seeking benefits. From individual decisions, collective patterns of large-scale structures emerge that can be quantitatively analyzed. However, most of the definitions that address the emergence of these patterns, such as the structures of schools and shoals, are based on conceptual criteria of sociability. In this work, we analyze the phase transition of zebrafish groups, through the variation of density. To do so, we used video cameras to capture the position and velocity of zebrafish in a controlled environment. We considered a circular container with a diameter of 50 cm and a water depth of 5 cm, tracking the trajectories of zebrafish, varying the number of individuals N. Then, we investigated the correlation measures of the derivatives of the polarization, aggregation, and Dcentroid parameters used in this work, between the time series for groups of N = 2, 13, and 30 individuals, using the q-gaussian parameter that served to reinforce schools-shoals phase transitions of zebrafish. Thus, we are able to characterize a phase transition between fish groups through the average values of the time series of polarization, aggregation, and D-centroid parameters, influenced by density variation. In addition, we observed variation in the correlation between fish through the fluctuations of these same parameters. With the experimental data of these parameters, we were able to quantify the behavior of schools and shoals during our analyses
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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