1,720,965 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
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
PW laser characterization
No full textSupplementary material of the thesis “Development of ultra-stable characterization techniques for ultrashort laser beams”. Spatiospectral characterization of the ATLAS-3000 laser relative to 800 nm, thus assuming flat phase at that wavelength. Measurement done outside the vacuum chamber using an achromatic imaging system to reduce the 20 cm beam diameter to mm-scale and characterized with a 3-mm-thick calcite cut with 45° optical axis angle. Spatiospectral intensity (a) and phase (b) profiles evolution.Funding: Junta de Castilla y León and European Regional Development Fund (SA136-P20); Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación (PID2020-119818GB-I00
Resumen de tesis. Development of ultra-stable characterization techniques for ultrashort laser beams
Get PDF[EN]The dramatic evolution that the laser Science has undergone in the last six decades, and particularly in the field of ultrashort pulses, has been accompanied by breakthrough advances in the development of techniques for their characterization. Despite the large number of characterization techniques developed in the last two decades, it is still necessary to Implement simpler and more robust techniques that can also operate in multiple spectral ranges.
This Thesis is devoted to the study and development of temporal and spatiotemporal characterization techniques with compact and stable configurations, which are versatile, e.g., to analyze ultrashort laser beams with
different temporal durations and in various spectral regions. The structure of this Thesis is made up of four main blocks. Firstly, a brief introduction to ultrafast optical metrology and the state of the art of spatial, temporal and spatiotemporal characterization techniques is presented in Part I. Then, Part II is focused on the review and extension of the capabilities of the amplitude swing temporal characterization technique, demonstrating three key advances: operation in different spectral regions from visible to near-infrared, with a tunability range spanning of more than one octave; Characterization of ultrashort pulses in the few-cycle regime; or study of the implementation with different amplitude modulation schemes.
In addition, a new retrieval algorithm is developed to analyze the amplitude swing traces based on differential evolution strategies. Thirdly, the fundamentals, operation range and experimental demonstration of a spatiotemporal
characterization technique based on bulk lateral shearing interferometry are depicted in Part III. Furthermore, the technique is applied to characterize complex spatiotemporal couplings, like constant and time-varying optical vortices or the aberrations when focusing with astigmatic lenses. Finally, the main conclusions of the work and future perspectives are discussed in Part IV[ES]La drástica evolución que ha experimentado la ciencia láser en las últimas seis décadas, y en particular en el campo de los pulsos ultracortos, ha ido acompañada de grandes avances en el desarrollo de técnicas para su caracterización. A pesar de la gran cantidad de métodos de caracterización desarrollados en las últimas dos décadas, aún es necesario implementar sistemas más simples y robustos que también puedan operar en múltiples rangos espectrales. Esta Tesis está dedicada al estudio y desarrollo de técnicas de caracterización temporal y espaciotemporal con configuraciones compactas y estables, que sean versátiles para, por ejemplo, analizar haces láser ultracortos con
diferentes duraciones temporales y en diversas regiones espectrales. La estructura de la Tesis está dividida en cuatro bloques principales. En primer lugar, en la Parte I se presenta una breve introducción a la metrología
óptica ultrarrápida y los avances de las técnicas de caracterización espacial, temporal y espaciotemporal a lo largo de los últimos años. Después, la Parte II se enfoca en la revisión y extensión de las capacidades de la técnica de caracterización temporal amplitude swing, demostrando tres avances clave: operación en diferentes regiones espectrales desde visible hasta infrarrojo cercano, con un rango de sintonizabilidad que abarca más de una octava;
caracterización de pulsos ultracortos en régimen de pocos ciclos; o estudio de diferentes esquemas de modulación de amplitud. Además, se implementa un nuevo algoritmo de reconstrucción para analizar las trazas del sistema amplitude swing basado en las estrategias Differential Evolution. En tercer lugar, en la Parte III se describen los fundamentos, el rango de operación y la demostración experimental de una técnica de caracterización espaciotemporal basada en la interferometría lateral compacta (bulk lateral shearing interferometry). Además, la técnica se emplea para caracterizar acoplamientos
espaciotemporales complejos, como son los vórtices ópticos constantes y variables en el tiempo o las aberraciones introducidas al focalizar haces láser con
lentes astigmáticas. Finalmente, en la Parte IV se resumen las principales conclusiones y futuras líneas de trabajo.Thesis memory and supplementary material folder: Vídeo 1 ("VideoThesis_GeneralizingAswing_Noise.avi"), Noise analysis amplitude swing configurations video. Vídeo 2 ("VideoThesis_Vortices_ProofOfConcept.avi"), Proof of concept spatiotemporal technique video. Vídeo 3 ("VideoThesis_Vortex_NIR_Lneg1.avi"), Near-infrared vortex video: orbital angular momentum of −1. Vídeo 4 ("VideoThesis_Vortex_NIR_L1.avi"), Near-infrared vortex video: orbital angular momentum of +1. Vídeo 5 ("VideoThesis_Vortex_NIR_L3.avi"), Near-infrared vortex video: orbital angular momentum of +3. Vídeo 6 ("VideoThesis_Vortex_VIS_Lneg2.avi"), Visible vortex video: orbital angular momentum of -2. Vídeo 7 ("VideoThesis_Vortex_VIS_L2.avi"), Visible vortex video: orbital angular momentum of +2. Vídeo 8 ("VideoThesis_Vortex_VIS_L4.avi"), Visible vortex video: orbital angular momentum of +4. Vídeo 9 ("VideoThesis_TimeVaryingVortex_Exp.avi"), Time varying vortex video: Experiment. Vídeo 10 ("VideoThesis_TimeVaryingVortex_Sim.avi"), Time varying vortex video: Simulation. Vídeo 11 ("VideoThesis_Astigmatic_Biconvergent.avi"), Astigmatic beam video: z = da = 49 cm. Vídeo 12 ("VideoThesis_Astigmatic_ConvDiv.avi"), Astigmatic beam video: z = db = 137 cm
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
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