1,720,964 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
Study of the energy and system size dependence of particle production in high energy collisions
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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
Formation du Plasma de Quark et de Gluon : comprehension de la dépendance en énergie et de la taille du système
No full textLa ChromoDynamique Quantique (CDQ) décrit les interactions entre les partons. Ces partons sont confinés dans les hadrons, cependant la CDQ prédit un nouvel état de la matière où les partons sont dé-confinés des hadrons : Le Plasma de Quarks et de Gluons (PQG). L'étude du PQG est un axe de recherche challengeant puisque l'on observe expérimentalement les hadrons et non les partons. Dans cette thèse, j'étudie les anisotropies des angles azimutaux de la production de particule qui est directement liée à l'anisotropie du fluide. Cette anisotropie, due à une anisotropie spatiale initiale, donne des informations sur les propriétés du PQG et son expansion. qui est directement liée à l'anisotropie du fluide. On observe des effets « d'écoulement » lors des collisions d'ions lourds (AA) aux hautes énergies du RHIC et du LHC mais également aux basses énergies du Beam Energy Scan (BES). Récemment, des effets d'écoulement ont été également observés lors des collisions de petits systèmes (pp). La problématique de cette thèse est : Est-ce qu'un « plasma en expansion collectif » est créé dans tous les systèmes : grand (AA) ou petit (pp) des basses énergies du BES aux hautes énergies du LHC ? EPOS est un générateur d'évènements dédie à l'étude des collisions d'ions lourds et proton-proton. J'analyse l'écoulement anisotropique avec EPOS pour tous types de systèmes (pp, AA), énergies (LHC, RHIS, BES), pour tous types de « sondes » d'écoulement. Pour effectuer mon analyse, j'ai développé un framework facilement utilisable indépendamment des futurs développements d'EPOS. C'est très important car les résultats de mon analyse vont impacter sur les prochaines mises à jour du modèle à petite taille de système et à basse énergie.Quantum ChromoDynamics (QCD) describes the interaction between partons (nuclear matter's degrees of freedom). These partons are usually confined into hadrons, however QCD predicts that a new state of matter exists where partons are deconfined from hadrons: the Quark Gluon Plasma (QGP). The QGP is formed in high energy heavy ion collisions. QGP study is exiting and theoretically challenging research field mainly because instead of partons, hadrons are observed. In this thesis, I study anisotropies in the azimuthal angle of particle production, which is directly related to the fluid's anisotropy. The fluid anisotropy is the response of the system to some initial space anisotropy and provides information on the properties of the QGP and its expansion. As in heavy ion (AA) collisions at high energies of RHIC and LHC, “flow-like” effects are hinted at Beam Energy Scan (BES) low energies. Very recently, unexpected “flow-like features” have also been observed in small systems like proton-proton (pp). In this thesis, I try to answer the following question: Is there a “collectively expanding plasma” in all systems : big (PbPb) or small (pp), from BES low energies to LHC higher energies? EPOS is an event generator dedicated to the study of proton-proton and heavy ion collisions. I analyze anisotropic flow with EPOS for all kind of systems (pp, AA), energies (LHC, RHIC, BES), and all kinds of flow “probes”. To perform my analysis, I developped a framework that can already be easily used, independently of further EPOS's developments. This fact is very important, because results of this analysis will impact incoming updates of the model at little system sizes and low energies
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
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