1,720,957 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
Simulations of axion string-wall networks
No full textThis thesis investigates the reliability of lattice simulations to reproduce the dynamics of the network of topological strings and domain walls that forms during the cosmological evolution of the axion field. Lattice simulations of axion string-wall networks are not capable of resolving the disparity in scale between the inter-string separation and string core size that exists for physically relevant axion models, but such simulations have been relied upon in the literature, without verification, to reproduce the dynamics of physical systems and place lower bounds on the axion mass. We performed lattice simulations of axion string-only networks that varied lattice parameters and simulations of the formation and collapse of string-wall networks that varied the ratio of string separation to core size. We find logarithmic corrections, dependent on the string separation-to-core ratio, to the scaling behaviour of axion string networks reported in past literature. We further see some indication that the dynamics of string-wall network collapse varies as this ratio changes. These results suggest that network dynamics could vary significantly for realistic networks compared to what lattice simulations are capable of resolving.Cette thèse examine si des simulations sur réseau peuvent reproduire la dynamique du système des cordes cosmiques et des murs de domaines qui se forme pendant l'évolution cosmologique du champ de l'axion. Les simulations sur réseau ne peuvent pas résoudre la disparité de l'échelle entre la séparation des cordes et l'épaisseur d'une corde qui existe pour des modèles physiquement pertinents de l'axion, mais dans la littérature on compte sur ces simulations, sans vérification, pour reproduire la dynamique des systèmes réalistes et mettre des limites inférieures sur la masse de l'axion. Nous avons fait des simulations sur réseau des systèmes de cordes dans lesquelles les paramètres du réseau ont été variés et aussi des simulations de la formation et la désintégration des systèmes de cordes et murs dans lesquelles le rapport de la séparation des cordes à l'épaisseur d'une corde a été varié. Nous trouvons que la dynamique des systèmes de cordes a une dépendance logarithmique du rapport séparation-épaisseur de corde, en contraste avec les résultats dans la littérature où la dynamique de ces systèmes est invariante d'échelle. Également, nos résultats suggèrent que la dynamique de la désintégration des systèmes cordes-murs dépend du rapport séparation-épaisseur de corde. Ces résultats indiquent que la dynamique des systèmes cordes-murs réalistes peut être considérablement différentes de la dynamique des systèmes que les simulations sur réseau sont capables de résoudre
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
White dwarfs as probes of novel physical phenomena
No full textWhite dwarfs are the final state of most stars once nuclear burning in the core has finished, leaving a remnant that evolves through a straightforward cooling process that is largely thought to be well-understood. The electron-degenerate core of a white dwarf is an extreme environment that provides a testbed of physics in regimes not achievable with ground-based experiments. In this dissertation, observations of white dwarfs are used to test white dwarf cooling theory and look for evidence of novel physical phenomena. The cooling and kinematics of ultramassive white dwarfs in the solar neighbourhood are analysed using Gaia EDR3 observations to reinvestigate an anomalous cooling delay previously reported based on earlier Gaia DR2 observations, which challenged the conventional understanding of white dwarf cooling. The cooling of white dwarfs in the globular cluster 47 Tucanae is also analysed in detail by comparing cooling models to HST data to both test the implementation of element diffusion in stellar evolution simulations and determine the values of parameters important for modelling white dwarf cooling like the white dwarf mass and envelope thickness. A thorough understanding of these properties enables the cooling of white dwarfs to be used to indirectly search for evidence of novel particles such as axions. The emission of axions produced in the core of a white dwarf via axion bremsstrahlung would provide an additional energy loss mechanism and thus affect the cooling rate. A new bound on the axion-electron coupling of gₐₑₑ ≤ 0.81 × 10⁻¹³ is derived from the cooling of white dwarfs in 47 Tucanae. This improves upon previous constraints by nearly a factor of two and excludes the range of values favoured by the hints of axions suggested by galactic white dwarf luminosity functions. Axions could also be produced in the core of a very hot, magnetic white dwarf like ZTF J1901+1458 via the ⁵⁷Fe transition and then convert to photons in the magnetosphere, and it is shown that X-ray observations of ZTF J1901+1458 by NuSTAR to search for the corresponding signal could probe the coupling of axions to nucleons with better sensitivity than both current and future planned ground-based observations.Science, Faculty ofPhysics and Astronomy, Department ofGraduat
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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