1,720,981 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

    Get PDF
    The 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 PDF
    We 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

    Atomic and electronic structure at transition metal doped LaAlO3/SrTiO3 interface

    No full text
    La mise en évidence d'une conductivité métallique à l'interface entre deux oxydes isolants, le SrTiO3 et le LaAlO3, a ouvert un champ nouveau pour l'électronique tout oxyde (A. Ohtomo & H. Y. Hwang, Nature 427, 2004). Au-delà du fort potentiel applicatif de cette découverte, par exemple pour l'électronique de faible puissance, de nombreuses questions restent posées sur les propriétés de ces interfaces et les différents moyens de les contrôler. L'apparition de la conductivité à l'interface LaAlO3 / SrTiO3 est attribuée à la survenue d'une reconstruction électronique au-dessus d'une épaisseur critique de 4 cellules unités (u.c.) de LaAlO3, visant à compenser la discontinuité de charge à cette interface entre matériaux polaire (LaAlO3) et non polaire (SrTiO3). En plus de cet effet, qui requiert une interface d'excellente qualité, divers paramètres sont susceptibles d'affecter les propriétés de cette interface et un effort de recherche très important porte sur le contrôle et l'amélioration de ces propriétés par des moyens tels que le changement de la nature du substrat, l'application d'un champ de contraintes ou l'introduction de légères modifications chimiques dans la couche ou à l'interface. Ce travail de thèse participe à cet effort en explorant les propriétés de transport et la structure fine des interfaces LaAlO3 / SrTiO3 dopées avec des atomes de métaux de transition. Il est centré sur la fabrication et l'étude d'interfaces LaAlO3 / SrTiO3 dopées avec des atomes d'iridium ou de cobalt. La croissance de nanostructures de haute qualité, typiquement LaAlO3 (5 u.c.) / SrTiO3 dopé (1 u.c.) / SrTiO3 (substrat), a été effectuée dans un bâti de dépôt laser pulsé (PLD) équipé d'un RHEED in situ. L'effet des dopants Ir ou Co sur les propriétés de transport et sur la structure électronique et atomique de l'interface LaAlO3 / SrTiO3 a été analysé en fonction du niveau de dopage grâce à une combinaison de différentes méthodes expérimentales et de calculs DFT. En particulier, des investigations par des techniques avancées comme la diffraction de photoélectrons sur synchrotron (XPD) et la microscopie électronique de résolution atomique en mode STEM-HAADF ont été mises en œuvre pour sonder la structure locale à l'interface et quantifier le niveau de déformation dans la couche LaAlO3. La structure électronique a été étudiée par spectroscopie de perte d'énergie électronique dans un STEM. Les résultats montrent qu'il est possible d'induire des changements dans les propriétés des interfaces LaAlO3 / SrTiO3 en dopant la surface de SrTiO3 avec un dopant et une concentration appropriés. En particulier, les effets du niveau de dopage sur la déformation élastique et les distorsions locales dans les couches LaAlO3 et ses conséquences sur les propriétés mesurées sont décrits.The demonstration in 2004 of a metallic conductivity at the interface between two insulating oxides, SrTiO3 and LaAlO3, opened a new field for all-oxide electronics (A. Ohtomo & H. Y. Hwang, Nature 427, 2004). Beyond the important applicative potential of this discovery for multifunctional and low power electronics, many questions remain about the properties of such interfaces and the different ways to control them. The occurrence of a conductive behaviour of the LaAlO3 / SrTiO3 interface is attributed to the advent of an electronic reconstruction above a critical thickness of 4 unit cells (u.c.) of LaAlO3, in order to compensate the charge discontinuity at the interface between a polar (LaAlO3) and a non-polar (SrTiO3) materials. In addition to this effect, which implies an interface of excellent quality, various parameters are likely to affect the properties of this interface, and a major research effort aims to control and improve these properties by ways such as the change in the nature of the substrate, the application of a stress field or the introduction of slight chemical modifications in the layer or at the interface. This thesis participates to this effort by exploring the transport and structural behaviour of LaAlO3 / SrTiO3 interfaces doped with transition metal atoms. It focuses on the fabrication and study of LaAlO3 / SrTiO3 interfaces doped with iridium or cobalt atoms. High quality nanostructures, typically LaAlO3 (5 u.c.) / doped-SrTiO3 (1 u.c.) / SrTiO3 (substrate), were grown by pulsed laser deposition (PLD) equipped with in-situ RHEED. The effect of Ir or Co dopants on both the transport properties and the electronic and atomic structure of the LaAlO3 / SrTiO3 interface was analysed as a function of the doping level thanks to a combination of different experimental methods and DFT calculations. In particular, advanced investigations by hard X-ray photoelectron diffraction on a synchrotron facility and by atomically resolved high angle annular dark field- scanning transmission electron microscopy (HAADF-STEM) were implemented to probe the local structure at the interface and quantify the level of strain in the LaAlO3. The electronic structure was investigated by electron energy loss spectroscopy in a STEM. Our results show that it is possible to induce changes in the properties of the LaAlO3 / SrTiO3 interfaces by doping the SrTiO3 surface with suitable dopant and concentration. In particular, effects of the doping level on the elastic deformation and the local distortions in the LaAlO3 layers and its consequences on the measured properties are described

    Dispelling the Myths Behind First-author Citation Counts

    Get PDF
    We 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

    Author Index

    No full text
    Nao informado

    koamabayili/VECTRON-author-checklist: VECTRON author checklist

    No full text
    We 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
    corecore