1,720,969 research outputs found
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
Electrical and all-optical poling of nonlinear optical materials: relaxation dynamics
Full text linkIl presente lavoro è motivato dalla necessità di trovare nuovi materiali polimerici o ibridi organici-inorganici per la realizzazione di modulatori elettroottici. Per essere utilizzati in un dispositivo reale, i materiali dotati di proprietà ottiche non lineari devono possedere elevata attività non lineare e stabilità temporale. Affinché un materiale esibisca proprietà ottiche non lineari del secondo ordine, esso deve essere sottoposto ad una procedura post-deposizione che definisca una direzione preferenziale in un sistema in partenza centro-simmetrico. A questo scopo sono state utilizzate due diverse tecniche di orientamento: corona e all-optical poling. La prima tecnica, studiata nel laboratorio NeMO, utilizza un campo elettrico statico per orientare le molecole, la cui mobilità viene aumentata innalzandone la temperatura. La seconda, utilizza la sovrapposizione di due sorgenti coerenti alle frequenze ω e 2ω per indurre una polarizzazione su campioni mantenuti a temperatura ambiente. In particolare, questa parte di lavoro è stata sviluppata nel Laboratoire des Propriétés Optiques des Matériaux et Applications (POMA) presso l’Università di Angers, grazie ad una borsa di studio finanziata dal COST P8. Grazie a queste tecniche di poling, i dipoli delle molecole possono essere orientati in una direzione parallela o perpendicolare alla superficie del film. Tale orientazione è stata caratterizzata tramite misure di assorbimento di luce polarizzata (PAS) e di generazione di seconda armonica (SHG). Utilizzando la temperatura come agente degradante, sono stati effettuati test di invecchiamento accelerato su film sottili di materiale polimerico e ibrido organico-inorganico sintetizzato con la tecnica sol-gel. Le curve di decadimento rivelano un andamento doppio esponenziale. Riportando il tempo di rilassamento lento in funzione della temperatura di invecchiamento, è stato possibile estrapolare, tramite un relazione tipo-Arrehnius, il tempo di rilassamento a temperatura ambiente. Due materiali sono risultati promettenti per le applicazioni desiderate: un sistema polimerico basato su una poliimide e un sistema ibrido. La realizzazione di un dispositivo elettroottico verrà realizzata in collaborazione con un’industria italiana. Questo lavoro di tesi rientra nell’ambito di un progetto europeo (ODEON) ed è stato sviluppato principalmente nel laboratorio NeMO presso l’Università di Roma “Tor Vergata”.The present thesis is motivated by the attempt to find polymeric or hybrid organic-inorganic materials for electrooptic modulators. For practical uses, nonlinear optical (NLO) materials must possess both large nonlinearity and temporal stability. Second order NLO properties appear after some additional post-deposition procedures. Indeed, after deposition, these composed materials are centrosymmetric and, as such, not endowed of second order properties. Poling, i.e. the orientation of the molecular dipoles, is necessary in order to break this centrosymmetry. Two different poling methods are investigated and discussed: corona and all-optical poling. The first technique, developed in the NeMO laboratory, involves a dc electric field, used to orient the dipoles of the material at a temperature where the molecule dipoles can rotate. The second one uses two coherent sources possessing different frequencies (ω and 2ω) to induce a reversible static polarization inside the medium at room temperature. This last work was performed in the Laboratoire des Propriétés Optiques des Matériaux et Applications (POMA) at the University of Angers thanks to the COST P8 grant. By poling, the dipoles can be oriented parallel or perpendicular to the film plane. Linear (Polarized Absorption Spectroscopy-PAS) and nonlinear (Second Harmonic Generation-SHG) characterizations are performed on the studied systems in order to reveal the orientation. Accelerated aging tests are performed using temperature as degrading agent and polar order decay monitored by SHG. All the decay curves are well fitted by a double exponential function. An extrapolation of the slower relaxation time using the Arrhenius model, permits to obtain the stability of nonlinear properties at room temperature. Macroscopic second order nonlinearities, orientation mechanisms (raise and decay of the poled order responsible for the nonlinearity) and chemical nature of different systems are discussed. At least two promising materials are found, a polyimide-based and a hybrid sol-gel-based system, and the fabrication of a prototype of electrooptic modulator is envisaged in collaboration with the research centers of some Italian private companies. This work is pursued mainly under the ODEON European project and performed in the NeMO laboratory at the University of Roma "Tor Vergata"
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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