1,720,981 research outputs found
Analysis of neutron-rich isotopes around the Z-38 region populated through a heavy-ion fission reaction
Get PDFAbstract. The study of neutron-rich nuclei is currently one of the most active research fields in nuclear physics. The neutron excess that these nuclei contain in comparison to the stable nuclei induces new physics phenomena such as changes of the so called magic numbers given by the nuclear shell model, which leads to unexpected deformations of the nuclear shape of these nuclei far away from the stability line. In the last decades, neutron-rich nuclei with a number of protons (Z) near 38 have gained attention due to the evolution of their nuclear deformation as a function of the number of neutrons. The most remarkable case corresponds to Zirconium (Z=40), where the nuclear deformation changes from a quasi-spherical shape for 96Zr, to a highly prolate deformation as in the case of 104Zr. Nevertheless, the experimental study of this behaviour has not been completed yet since the low production cross-section of these isotopes demands improved facilities only recently developed, with a detection eficiency high enough to clearly detect these nuclei together with the gamma radiation emmited by them when de-excite. In 2011, at the Laboratori Nazionali di Legnaro, Italy, neutron-rich nuclei in the Z-38 region were populated by the fission reaction of a 136Xe projectile colliding against a 238U target, at a beam energy of 960 MeV. In order to detect the nuclear species produced and the gamma rays emmited by them, the new -ray detector AGATA Demonstrator was used in coupling with the mass spectrometer PRISMA. In this thesis the data obtained has been analysed in order to determine the mass distribution for the detected neutron-rich Zirconium and Strontium isotopes together with their associated gamma spectrum.El estudio de núcleos ricos en neutrones es uno de los actuales campos de investigación más activos en física nuclear. El exceso de neutrones que estos presentan en comparación con los núcleos estables genera fenómenos físicos no observados previamente, por ejemplos, el cambio en los llamados números mágicos predichos por el modelo de capas nuclear, lo que lleva a comportamientos inesperados de la deformación nuclear para estos isótopos lejos de la línea de estabilidad. En las ultimas décadas, los isótopos ricos en neutrones con un número de protones (Z) cercano a 38 han ganado atención debido a la evolución de su deformación como función del número de neutrones. El caso más importante corresponde al Zirconio (Z=40), donde la deformación nuclear cambia desde una forma cuasi-esférica para el 96Zr hasta una deformación altamente prolata para el 104Zr. No obstante, el análisis experimental de este fenómeno no se ha completado pues la producción de estos núcleos inestables tiene una sección eficaz tan baja que su detección en conjunto con la radiación gamma que emiten cuando se desexcitan, con una eficiencia tal que permita acumular una adecuada estadística, es un reto que sólo ha podido enfrentarse recientemente gracias a los últimos desarrollos en las herramientas experimentales de espectroscopía nuclear. En el año 2011, en las instalaciones del Laboratori Nazionali di Legnaro, Italia, núcleos ricos en neutrones con Z-38 fueron creados usando la reacción de fisión inducida de un proyectil de 136Xe colisionando contra un blanco en reposo de 238U, con una energía cinética de 960 MeV. Para detectar las especies nucleares producidas y la radiación gamma emitida producto de su desexcitación, se usó un montaje experimental compuesto por el nuevo detector gamma AGATA Demonstrator acoplado con el espectrómetro de masas PRISMA. En esta tesis se analizan los datos obtenidos en el experimento para determinar la distribución de masas detectadas para los isótopos de Zirconio y Estroncio, y se obtienen los espectros de radiacióon gamma asociados a estos núcleos.Maestrí
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
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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