1,721,063 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
Studying the dynamics of dendrite development in the sensory neurons of Drosophila
No full textLes dendrites des neurones présentent une grande diversité dans leur morphologie qui s’avère être cruciale pour l’intégration des informations qu’elles reçoivent. Bien que plusieurs molécules et voies de signalisation sont connues pour gouverner le développement des dendrites, comment ces molécules instruisent l’architecture complexe et stéréotypée des arborisations dendritiques reste mal connu. Deux mécanismes de morphogenèse ramifiée ont émergé de l’étude de systèmes ramifiés pour lesquels une description de leur développement était rendue possible. Les systèmes déterministes ont des points de branchements stéréotypés et prédictibles, souvent contrôlés par des signaux développementaux externes et préétablies. Les systèmes auto-organisés sont plus variables mais les ramifications suivent des règles statistiques qui finissent par produire des morphologies similaires. Nous avons étudié les neurones multi-dendritiques chez la Drosophile, qui constituent un système de choix pour comprendre les règles qui gouvernent la morphologie des dendrites. Premièrement, nous avons d’abord découvert qu’une grande partie de la morphogenèse ramifiée des dendrites est établie au cours de l’embryogenèse, après quoi le système déjà structuré s’adapte seulement à l’échelle au cours de la croissance larvaire. Nous avons ensuite développé un nouveau protocole pour observer le développement embryonnaire des dendrites in vivo qui suggère que la croissance de dendrite primaire est déterministe alors que celle des dendrites secondaires est plutôt auto-organisée. Nous avons de plus montré que les dendrites secondaires sont contrôlées au moins en partie par la répulsion au soi orchestrée par dscam1.Neurons have very specific dendrite morphologies crucial for the correct integration of inputs that they receive. Dendrite morphology is likely shaped by both internal and external inputs that are tightly controlled in space and time. Although several molecules and pathways involved in dendrite patterning are known, how these molecules instruct neurons to achieve their type-specific morphology remains unclear. This is mainly due to a lack of precise descriptions during dendrite development as in vivo live imaging of neuronal systems has several technical challenges. However, two mechanisms of branching morphogenesis emerge from studying branched systems in which such precise descriptions during development have been possible. Deterministic systems have stereotyped, predictable branch points often controlled by extrinsically patterned developmental cues. Self-Organized systems are variable but branching features follow conserved statistical rules that ultimately result in similar morphologies. Our study therefore aimed to understand whether neuronal morphogenesis was deterministic or self-organized. We used the Drosophila multi-dendritic neurons that been a favored system for studying dendrite morphology. We first established that a majority dendrite patterning occurs during embryogenesis after which the dendrite pattern nearly scales with larval growth. We then developed a protocol to observe embryonic development of the dendrite, which suggested that the primary branches grow deterministically and that secondary branches might be self-organized. We further show that secondary branches are patterned at least partly by self-repulsion via dscam
Régulation d'un réseau biomécanique entraînant des changements de forme lors de morphogenese des tissus
No full textForces requises pour les changements de forme au cours de la morphogenèse des tissus sont générés par d’actine et de myosine. Durant ma thèse, je étudié le rôle de la réglementation MyoII par la voie Rho1-Rok durant l’élongation de l’ectoderme ventro-latéral par intercalation cellulaire. Les pulsations de MyoII médio-apicale se déplacent de manière anisotrope vers les jonctions parallèles avec l’axe dorso-ventral (ou jonctions verticales). Ceci provoque le rétrécissement graduel des jonctions qui sont stabilisées par une population de MyoII polarisée dans le plan du tissu et enrichie au niveau de ces jonctions. Les mécanismes cellulaires qui régulent la pulsatilité, la stabilité et la polarité de la myosine II restent à élucider. J’ai identifié deux propriétés cruciales de la dynamique de la myosine II régie par phospho- à savoir la cinétique d’échange gouvernée par les cycles de phosphorylation-déphosphorylation des chaines légères régulatrices de la MyoII (RLC) et l’advection due à la contraction des moteurs sur le réseau de F-actine. Contrôle spatial sur le chiffre d'affaires MyoII établit 2 régimes stables des taux élevés et faibles dissociation résultant dans MyoII polarité. Pulsatilité est un comportement auto-organisé qui émerge à taux de dissociation intermédiaires permettant d'advection MyoII et les régulateurs en amont. Dans la deuxième partie de ma thèse, je l'ai montré que la protéine GPCR- GRsmog et la brume, et la voie G-protéines en aval permettent l'activation progressive des MyoII, établissant pulsatilité et de la stabilité pour produire des déformations de forme polarisées cours de la morphogenèse.Forces required to power shape changes during tissue morphogenesis are generated by non-muscle MyosinII (MyoII) pulling filamentous actin. During my PhD, I investigated the role of MyoII regulation through the conserved Rho1-Rok pathway during Drosophila germband extension. The morphogenetic process is powered by cell intercalation involving shrinkage of junctions in the dorsal-ventral axis (‘vertical junctions’) followed by junction extension in the anterior-posterior axis. Advances in light microscopy revealed that the actomyosin networks exhibit pulsed contractions to power junction shrinkage, and alternate with steps of stabilization by MyoII enriched on vertical junctions (planar-polarity) to result in irreversible shape changes. Although described in many different contexts, the underlying mechanisms of this ratchet-like behavior remained unclear. Using genetic and biophysical tools, quantitative imaging and subtle perturbations, I identified 2 critical properties underlying MyoII dynamics- turnover governed by phospho-cycling of the MyoII Regulatory Light Chain, and advection due to contraction of the motors on actin networks. Spatial control over MyoII turnover establishes 2 stable regimes of high and low dissociation rates resulting in MyoII planar polarity. Pulsatility is a self-organized behavior that emerges at intermediate dissociation rates enabling advection of MyoII and upstream regulators. In the second part of my thesis, I showed that G protein coupled receptors- GRsmog and Mist, and the downstream G-protein pathway allow step-wise activation of MyoII, establishing pulsatility and stability, to drive polarized shape deformations during morphogenesis
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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