1,720,959 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
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
Lifetime Prediction of Current-and Temperature-Induced Degradation in Silicone-Encapsulated 365 nm High-Power Light-Emitting Diodes
Full text linkWe report on the degradation mechanisms and dynamics of silicone encapsulated ultraviolet A (UV-A) high-power light-emitting diodes (LEDs), with a peak wavelength of 365nm. The stress tests were carried out for a period of 8665 hours with forward currents between 350mA and 700mA and junction temperatures up to 132°C. Depending on stress condition, a significant decrease in optical power could be observed, being accelerated with higher operating conditions. Devices stressed at a case temperature of 55 °C indicate a decrease in radiant flux between 10-40% varying with measurement current, whereas samples stressed at higher case temperatures exhibit crack formation in the silicone encapsulant accompanied by electromigration shorting the active region. The analyzed current and temperature dependency of the degradation mechanisms allows to propose a degradation model to determine the device lifetime at different operating parameters. Additional stress test data collected at different aging conditions is used to validate the model's lifetime predictions.</p
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
Spectra and energy levels of Gd3+(4f(7)) in AlN
No full textWe report crystal-field splitting investigations of Gd3+(4f(7)) energy levels determined from high resolution energy (Stark) level cathodoluminescence (CL) spectroscopy of Gd-implanted 2H-aluminum nitride (AlN) in the wavelength range 250 to 320 nm and at temperatures 12, 77, and 300 K. The CL spectra are interpreted in terms of lattice-sum and crystal-field splitting models that assume implanted Gd replaces Al substitutionally in cationic sites in AlN having C-3v point group symmetry. The CL spectra are associated with Gd3+ ions in a single site. A rms deviation of 7 cm-1 was obtained between 43 observed and calculated Stark levels. The intense UV emission at 318 nm (the P-6(7/2)-->S-8(7/2) transition) can be understood in terms of multiplet-to-multiplet branching ratios
Spectra and energy levels of Tm3+(4f(12)) in AlN
No full textWe report a detailed analysis of the cathodoluminescence spectra of Tm3+-implanted 2H-aluminum nitride (AlN) covering the wavelength range between 290 and 820 nm at temperatures between 12 and 60 K. More than 200 transitions are observed, of which more than 100 of these transitions can be identified from emitting multiplet manifolds I-1(6), D-1(2), and (1)G(4). Although the emitting levels are not observed directly, emission is also attributed to the P-3(2) and P-3(1) multiplet manifolds based on analyses of transitions to terminal levels F-3(4), H-3(5), and F-3(3). The observed crystal-field splitting of the ground-state multiplet manifold, H-3(6), and manifolds F-3(4), H-3(5), H-3(4), F-3(3), F-3(2), and (1)G(4) is established from an analysis based on matching repeated energy differences between transitions. This method is similar to one used in analyzing arc and spark spectra. Temperature-dependent spectra also establish the crystal-field splitting of the P-3(1) and part of the manifold splitting of emitting levels such as I-1(6). To establish an initial set of crystal-field splitting parameters, B-nm, that can be related to a physical model, we carried out a lattice-sum calculation by computing the crystal-field components, which are the coefficients in a multipolar expansion of the crystal field about the Al3+ sites that have C-3v symmetry in the lattice. Emission channeling experiments indicate that the Al3+ sites serve as the substitutional sites for Tm3+ in AlN. With only minor adjustments to the calculated centroids to account for J-mixing, the calculated crystal-field splitting of most multiplet manifolds, L-2S+1(J), of Tm3+(4f(12)) based on the B-nm obtained from the lattice-sum calculations, is in good agreement with the reported experimental splitting
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