1,720,972 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
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
The High-redshift Blazar MG3 J163554+3629: Physical Properties and the Enigma of Its Unexpected Supermassive Black Hole Growth
No full textThere is general consensus that active galactic nuclei (AGNs) derive their radiating power from a supermassive
black hole (SMBH) that accretes matter. Yet, their precise powering mechanisms and the resulting growth of the
SMBH are poorly understood, especially for AGNs at high redshift. Blazars are AGNs pointing their jet toward the
observer, thus being detectable from radio through gamma rays at high redshift due to Doppler boosting. The
blazar MG3 J163554+3629 is located at redshift z = 3.65 and it is a flat spectrum radio quasar (FSRQ). In this
work, we show the results of the modeling of its spectral energy distribution (SED) from radio to gamma rays with
a one-zone leptonic model. We estimate the uncertainties through a Markov Chain Monte Carlo approach. As a
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result, we infer the black hole mass MBH = 1.1-0.1 ́ 10 M and a modest magnetic field of
B = 6.56+0.13 ́ 10-2 G in line with the Compton dominance observed in high-redshift FSRQs. The emitting -0.09
region is outside the broad line region but within the region of the dust torus radius. The rather small accretion efficiency of η = 0.083 is not solely inferred through the SED modeling but also through the energetics. An evolution study suggests that in an Eddington-limited accretion process the SMBH did not have time enough to grow from an initial seed mass of ∼106Me at z ≈ 30 into a mass of MBH ≈ 109Me at z = 3.65. Faster mass growth might be obtained in a super-Eddington process throughout frequent episodes. Alternative scenarios propose that the existence of the jet itself can facilitate a more rapid growth
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
Hard X-Ray broadband spectroscopy of Mrk 876: characterizing its spectrum
No full textEver since the launch of the NuSTAR mission, the hard X-ray range is being covered to an unprecedented sensitivity. This range encodes the reflection features arising from active galactic nuclei (AGNs). Especially, the reflection of the primary radiation off the accretion disc carries the features of the manifestation of General Relativity described by the Kerr metric due to rotating supermassive black holes (SMBHs). We show the results of the broadband analyses of Mrk 876. The spectra exhibit the signature of a Compton hump at energies above 10 keV and a broadened and skewed excess at energies ∼6 keV. We establish this spectral excess to be statistically significant at 99.71 per cent (∼3σ) that is the post-trail probability through Monte Carlo simulations. Based on the spectral fit results and the significance of spectral features, the relativistic reflection model is favoured over the distant reflection scenario. The excess at ∼6 keV has a complex shape that we try to recover along with the Compton hump through a self-consistent X-ray reflection model. This allows inferring an upper limit to the black hole spin of a ≤ 0.85, while the inclination angle of the accretion disc results in i = 32.84, which is in agreement within the errors with a previous independent measurement (i = 15.4). While most spin measurements are biased towards high spin values, the black hole mass of Mrk 876 (2.4\times 10^{8}\, \mbox{M}_\odot \le MSMBH \le ~1.3 \times 10^{9}\, \mbox{M}_\odot) lies in a range where moderately spinning SMBHs are expected. Moreover, the analyses of 12 Chandra observations reveal for the first time X-ray variability of Mrk 876 with an amplitude of 40 per cent
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