1,720,953 research outputs found
Analysis of the changes in birefringence of a hollow core photonic fiber, by introducing anisotropic liquids into its core
No full textLa invención de la fibra de cristal fotónico de núcleo hueco ha ampliado el campo de investigación en el área de sensores de fibra óptica, principalmente por su aplicación al biosensado. El revestimiento microestructurado de la fibra y el mismo núcleo hueco, permiten infiltrar muestras líquidas para su análisis y estudio. Uno de los parámetros relevantes para el sensado puede estar asociado ya sea a la fase o al estado de polarización de la señal usada. En esos casos es importante caracterizar tanto la birrefringencia residual de la fibra como los cambios inducidos en ella por estos líquidos. En el presente trabajo de tesis se planteó la construcción de un sistema de llenado para infiltrar las fibras huecas con líquidos, compatible con un arreglo de análisis de polarización que usa una fuente sintonizable de luz láser. La precisión de medida del arreglo polarimétrico depende de la correcta alineación de la muestra de fibra óptica. Se seleccionó el método denominado butt-coupling, usando una punta de entrada de fibra SMF-28e. El sistema de llenado construido tiene paredes trasparentes que facilitan el proceso de alineación. La caracterización de la birrefringencia de la fibra fotónica de núcleo hueco se realizó analizando los cambios del estado de polarización de salida de una señal de entrada linealmente polarizada. Se realizaron barridos azimutales del estado de polarización de entrada (0 a 180 grados), que se repitieron cambiando la longitud de onda de entrada en un rango de trabajo de 1540 a 1560 nm (barrido espectral). Una vez concluido el trabajo experimental con la fibra de núcleo hueco, se realizó la infiltración del líquido por capilaridad. Se experimentó con 3 tramos de fibra de longitudes diferentes; al primero de 11.7 cm de largo se le introdujo Kahlúa (+), a un segundo tramo de 10.2 cm de longitud se le infiltró (R+) Limoneno y el tercero, de 10.2 cm de largo se infiltró con (R-,S-) Linalilo. Aunque los resultados obtenidos muestran cambios en la birrefringencia compatibles con la naturaleza quiral de los líquidos (dextrógira o levógira), en los dos últimos casos los valores experimentales mostraron una alta inestabilidad debida probablemente a la sensibilidad de las muestras a las condiciones ambientales. Las perturbaciones físicas dominantes que alteraron la birrefringencia de cada líquido se debieron a cambios en la temperatura, humedad y vibraciones. Cabe señalar que estos disturbios son despreciables al caracterizar fibras ópticas ...The invention of the hollow-core photonic crystal fiber has broadened the field of research in the area of optical fiber sensors, mainly because of its application to bio sensing. The microstructured coating of the optical fiber and the same hollow-core, allow infiltrating liquid samples for the analysis and study of different physical properties. One of the parameters relevant to the sensing may be associated with either the phase or the polarization state of the signal used. In these cases, the characterization of the fiber residual birefringence and the changes induced in it by these liquids are essential. In the present thesis work, we propose the construction of a filling system to infiltrate the hollow fibers with liquids, compatible with a polarization analysis arrangement using a tunable source of laser light. The measurement accuracy of the polarimetric setup depends on the correct alignment of the fiber optic sample. To optimize alignment we selected the method called “butt-coupling”, using an SMF-28e fiber input tip. The built filling system has transparent walls that facilitate the alignment process. The analysis of the changes in the output polarization state of a linearly polarized input signal allowed the birefringence characterization of the hollow-core photonic fiber. We realized azimuthal sweeps of the input polarization state (0 to 180 degrees), for each input wavelength in a working range of 1540 to 1560 nm (wavelength scanning).After completing the experimental work with the hollow-core fiber, we proceeded to infiltrate the liquid using capillarity. We worked with three fiber sections of different lengths; the first 11.7 cm long was infiltrated with Kahlua (+), a second 10.2 cm long section was infiltrated with (R +) Limonene, and for the third (10.2 cm long) we used (R-, S-) Linalyl. Although the results obtained show changes in birefringence compatible with the chiral nature of the liquids (dextrorotatory or levorotatory), for the last two liquids, the experimental values showed high instability, probably due to the sensitivity of the samples to the environmental conditions. Temperature, humidity, and vibrations were the dominant physical disturbances that altered sample birefringence, stable when characterizing conventional optical fibers
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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