1,723,353 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
Orbital-Selective Mott Transition out of Band Degeneracy Lifting
No full textWe outline a general mechanism for orbital-selective Mott transition, the coexistence of both itinerant and localized conduction electrons, and show how it can take place in a wide range of realistic situations, even for bands of identical width and correlation, provided a crystal field splits the energy levels in manifolds with different degeneracies and the exchange coupling is large enough to reduce orbital fluctuations. The mechanism relies on the different kinetic energy in manifolds with different degeneracy. This phase has Curie-Weiss susceptibility and non-Fermi-liquid behavior, which disappear at a critical doping, all of which is reminiscent of the physics of the pnictides. RI Dai, Xi/C-4236-2008; Capone, Massimo/A-7762-2008; de' Medici, Luca/H-5071-201
Wiring proton gradients for energy conversion
No full textLight-switchable buffer solutions based on merocyanine photoacids can be used as efficient photoenergy harvesting systems. Varying the solvation environment of merocyanine photoacids in water-methanol mixtures allows one to carefully tune their photoacidity, relaxation kinetics, and solubility, opening up the possibility to install persistent pH gradients of approximately 4 pH units under 500 nm light. When interfaced between two electrodes and exposed to asymmetric light irradiation, these solutions can be photoactivated precisely both in space and time, generating open circuit voltages as high as 240 mV that can last hours under steady-state irradiation - an outcome that is akin the peak performance of biological transmembrane proton pumps
Anaerobic digestion disposal of sewage sludge pyrolysis liquid in cow dung matrix and the enhancing effect of sewage sludge char
No full textSewage sludge pyrolysis liquid (SSPL) is a mixture of various toxic organic compounds and moisture, its disposal or valorization are crucial for the sustainability of any pyrolysis plant of sewage sludge (SS). As SSPL showed strong inhibition on anaerobic digestion (AD), in order to fulfill its clean disposal, the study investigates its AD in cow dung matrix under thermophilic condition with sewage sludge char (SSC) addition. Three SSCs produced at different temperatures and two biochars were added into the AD system for comparison. Batch experiments (55 °C, 26 days) reveal that addition of SSCs/biochars could increase cumulative methane yield by 57.5–128.7%/120.7–133.7% compared with the group without char addition. Among three SSCs, the one produced at 550 °C (550SSC) shows the best effect and has similar promotion effects to those of conventional biochars. The mechanism involved is explained by the following facts: SSCs/biochars addition alleviated microbial inhibition effect of SSPL by adsorbing the toxic organic compounds in the liquid at the early stage, hosting microbes to grow, improving the reaction rate and stabilizing the pH of AD system at around 8, finally helping to obtain an earlier occurrence of daily methane yield peak and contributing to higher methane yields. The rich trace elements contained in SSCs, especially in 550SSC, help to promote the growth of microbes and contribute to the decomposition of toxic organic compounds. GC-MS analyses of digestates reveal that SSPL can be well degraded with help of SSCs/biochars addition after AD process. The obtained results suggest that AD of SSPL in cow dung matrix with 550SSC addition is a reliable and economy alternative for its treatment and valorization
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
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