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
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
Study of particle-hole states in nuclei in the neighbourhood of ⁷⁸Ni with the ν-Ball spectrometer
No full textDans le cadre du modèle en couche, l’évolution des états de particules individuelles avec le rapport N/Z est un phénomène désormais bien établi. De nouveaux nombres magiques peuvent apparaître et d’autres disparaître localement. La question de la persistance des fermetures de couches loin de la stabilité présente un intérêt majeur pour la compréhension de l’interaction nucléaire et de la structure qui en découle. Le travail présenté dans cette thèse porte sur l’évolution du gap N=50 à l’approche du noyau de ⁷⁸Ni. Bien que des observations expérimentales récentes semblent indiquer le statut doublement magique de ce noyau, l’évolution de la taille du gap N=50, qui semble se stabiliser pour Z < 32, soulève encore des questions. L’étude de cette évolution peut se faire en étudiant les états issus de la promotion d’un neutron entre les états simples particules délimitant le gap, de l’état g9/2 à l’état d5/2. La configuration particule-trou résultante est à l’origine d’un multiplet de 6 états, de 2⁺ à 7⁺. Le suivi systématique des états de plus hauts spins, supposés dominés par cette configuration, peut être relié à l’évolution du gap N=50. De 2017 à 2018 s’est tenue à l’installation ALTO d’Orsay une grande campagne expérimentale utilisant le spectromètre γ hybride ν-Ball. La spectroscopie de réactions induites par neutrons rapides a été réalisée grâce au couplage avec la source de neutrons LICORNE. Cinq semaines ont été consacrées à des expériences de fission sur des cibles de ²³⁸U et, pour la première fois, de ²³²Th. Les fragments de fission produits ont pu être étudiés par spectroscopie γ en reconstruisant les coïncidences doubles ou triples entre les rayonnements émis au cours de leur désexcitation. Les schémas de niveaux de nombreux noyaux produits par ces mécanismes, notamment dans la région du ⁷⁸Ni, ont été reconstruits. Grâce à cette étude, il a été possible de placer deux nouvelles transitions et un nouvel état dans le schéma de niveaux du ⁸²Ge. L’énergie de ce nouvel état, supposé 7⁺, mesuré à 3947,9 keV a permis de confirmer la tendance de l’évolution du gap N=50. De plus l’attribution des spin-parités 5⁺ et 6⁺ pour les deux états à 2933,2 et 3227,6 keV est renforcée par la mesure d’une nouvelle transition reliant ces deux états, à 294,1 keV. Enfin, pour interpréter les évolutions des états de particules individuelles déduites de ces mesures expérimentales, l’utilisation d’un modèle de champ moyen relativiste est proposée : la brisure de la symétrie de pseudo-spin.In the framework of the shell model, the evolution of the single particle states with the N/Z ratio is clearly established phenomenon. Locally, new magic numbers can appear and others disappear. The question of the quenching of shell closures far from stability is of major interest for the understanding of nuclear interaction and the underlying nuclear structure. The work presented in this thesis concerns the evolution of the N=50 shell gap when approaching ⁷⁸Ni. Even if the doubly magic nature of this nucleus has been confirmed in 2019, the evolution of the gap energy, which presents a local minimum for ⁸²Ge, raises many questions. The study of this evolution can be done by looking at the states created by the promotion of a neutron through the gap, from the g9/2 shell to the d5/2 shell. This one particle – one hole configuration creates a multiplet of states with spin-parity ranging from 2⁺ to 7⁺. The systematic tracking of the highest spin states, supposed to be dominated by this configuration, can be directly related to the gap size evolution. From 2017 to 2018, an important experimental campaign has been held at the ALTO facility of Orsay, using the hybrid γ spectrometer ν-Ball. The spectroscopy of fast-neutron induced reactions has been realized thanks to the coupling with the LICORNE neutron source. Five weeks have been dedicated to fission experiments using targets of ²³⁸U and, for the first time, ²³²Th. The fission fragments have been studied using γ spectroscopy by reconstructing double and triple coincidences between the γ rays emitted during the deexcitation of the nuclei. The level schemes of many nuclei have been built, especially in the ⁷⁸Ni region. Thanks to this study, it was possible to place two new energy transitions and one new level in the level scheme of ⁸²Ge. The energy of this new - supposed 7⁺ - state measured at 3947,9 keV is in line with the trend of the N=50 shell gap evolution. Moreover, the spin-parity attribution for the 5⁺ and 6⁺ states is reinforced my the measure of a new transition between these two states, at 294,1 keV. Finally, the use of a relativistic mean field model is proposed to interpret the single particles states evolution deduced from these experimental measurements : the pseudospin symmetry breaking
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
STRUCTURE DES NOYAUX DE GERMANIUM ET DE GALLIUM RICHES EN NEUTRONS AU-DELA DE N EGAL A 50 A ALTO
No full textNowadays, the experimental progresses in nuclear physics, are in urge with the development of new facilities able to produce radioactive ions beams. For that purpose, the “Isotopic Separation On-Line” method combined with the use of the fission mechanism seems to be the future for the production of radioactive neutron rich nuclei. The Institut de Physique Nucléaire d'Orsay take its part of this development with the construction of the ALTO (“Accélérateur Linéaire et Tandem d'Orsay”) project. This ISOL facility is based on the use of an electron beam to induce the photofission of uranium. In july 2006, during the production yields measurements, this method has been proved to be viable. Moreover, the results extracted from measurements have highlighted some changes usefull to improve the production method.The ALTO facility is not limited to the production of neutron rich fission fragments. During a radioprotection measurement, a detection setup has been installed to study the radioactive decay of 84Ga. The analysis provided indications on the structure of 84Ga, 84Ge, 84As and 83Ge. For 84Ga, an isomeric state has been identified, and a configuration for it and the ground state has been proposed. For 84Ge, the first excited state 2+ and 4+ for which energy ratio provided indication on the expected collectivity beyond N=50. The evolution of this collectivity seems to show a weakening of the Z=28 shell gap close to 78Ni. With the same data, we built the very first level scheme for 84As. Configurations have been proposed for the excited sates of this nucleus. Lastly, to conclude on the 83Ge level scheme, a model to describe the weak coupling between a neutron and a core has been applied. First, it has been tested on the N=51 isotonic chain to prove its reliability. Its use for the 83Ge confirmed the existence of such a structure in this nucleus. The results obtained with that model have been extrapolated to predict the level scheme of 81Zn.Aujourd'hui, les progrès expérimentaux en physique nucléaire nécessitent le développement d'accélérateurs susceptibles de produire des faisceaux d'ions radioactif. Dans cette optique, la méthode « Isotopic Separation On-Line » combinée à l'utilisation du mécanisme de fission permet de produire des ions radioactif riches en neutrons. L'Institut de Physique Nucléaire d'Orsay participe à ce développement avec la construction du projet ALTO (Accélérateur Linéaire et Tandem d'Orsay). Cette installation de type ISOL utilise un faisceau d'électron pour induire la photofission de l'uranium. En juillet 2006, dans le cadre de mesure des taux de production, la viabilité de cette méthode a été démontrée. De plus, les résultats ont mis en évidence un ensemble de modifications capables d'améliorer la méthode de production. L'installation ALTO ne se limite pas à la fabrication de fragments de fission riches en neutrons. Au cours d'un test de radioprotection, un système de détection a été installé pour permettre l'étude de la décroissance radioactive de l'isotope 84Ga. L'analyse des données acquises au cours de cette mesure nous a permis d'apporter des indications sur la structure des noyaux de 84Ga, 84Ge, 84As et 83Ge. Pour 84Ga, nous avons identifié un état isomérique et proposé une configuration pour cet état et l'état fondamental du noyau. Pour 84Ge, nous avons observé les premiers états 2+ et 4+ dont le rapport des énergies nous a permis de conclure sur l'apparition de la collectivité attendue au-delà de N=50. L'étude de cette collectivité semble indiquer un affaiblissement du gap Z=28 à l'approche de 78Ni. Nous avons proposé le premier schéma de niveau de 84As. Nous avons aussi proposé une configuration pour les états observés de ce noyau. Enfin, pour interpréter le schéma de niveau de 83Ge, un modèle permettant de caractériser le couplage en un neutron et un cœur a été employé. Ce dernier a été appliqué à l'ensemble de la chaîne isotonique N=51 pour tester sa validité. Puis, son application au noyau de 83Ge a confirmé l'existence de ce type de structure dans ce noyau. Les résultats obtenus avec ce modèle ont été extrapolés afin de proposer une prédiction du schéma de niveau de 81Zn
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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