1,721,206 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
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
Vertically aligned carbon nanotubes on metal substrates : development of a sustainable low-temperature synthesis process
No full textL’émission toujours plus importante de gaz à effet de serre (GES) liée à notre mode de vie actuelle mènera à un réchauffement global moyen de 4°C en 2100 si aucune politique climatique n’est mise en place. Diverses applications utiles à la transition énergétique sont développées à partir de nombreux nanomatériaux aux propriétés exceptionnelles notamment les nanotubes de carbone verticalement alignés (VACNT). Cependant ils sont généralement synthétisés par « Catalytic Chemical Vapor Deposition » (CCVD) en une ou deux étapes à partir de précurseurs carbonés gazeux non renouvelable tels que l’acétylène. Pour mettre en accord les applications pour la décarbonation avec une origine décarbonée, il est important de trouver des alternatives à ce précurseur. En partenariat avec NAWAH, les objectifs de cette thèse sont de remplacer le précurseur acétylène par des précurseurs biosourcés dans le procédé de CCVD une étape (injection continue des précurseurs catalytiques et carbonés). De plus il s’agira également de comprendre l’influence de la nature du précurseur et des conditions de synthèse sur les caractéristiques des matériaux formés sur plusieurs natures de supports et de tester leur potentiel pour les applications visées notamment dans le domaine de l’énergie. Cette thèse démontre que les précurseurs biosourcés peuvent remplacer efficacement l’acétylène dans la croissance de VACNT par CCVD, en obtenant des matériaux aux caractéristiques similaires (hauteur, masse, densité, qualité...). Ainsi des tapis de 100 µm ont pu être obtenus à partir du couplage de l’éthylène avec le butanol, remplaçant le toluène précédemment utilisé comme solvant du ferrocène. Ces matériaux ont donné des résultats intéressants en terme de capacité volumique en tant qu’électrode de supercondensateur mais également en terme de rétention de capacité en tant qu’électrode de batterie. De plus, des tests de transposition à l’échelle semi- industrielle valide l’intérêt du procédé montre la flexibilité du procédé développé en laboratoire. Par ailleurs, des analyses physico- chimiques plus approfondies ont été menées pour mieux comprendre le rôle de ces précurseurs sur la croissance des VACNT en terme d’énergie d’activation de la croissance, de décomposition en phase gaz et d’interaction avec le substrat (aluminium, inox et cuivre).The ever-increasing emission of greenhouse gases (GHG) linked to our current lifestyles will lead to an average global warming of 4°C by 2100 if no climate policy is implemented. A number of nanomaterials with exceptional properties, notably vertically aligned carbon nanotubes (VACNTs), are being developed for a variety of applications useful to the energy transition. However, they are generally synthesized by “Catalytic Chemical Vapor Deposition” (CCVD) in one or two steps from non-renewable gaseous carbon precursors such as acetylene. To match decarbonation applications with a decarbonated origin, it is important to find alternatives to this precursor. In partnership with NAWAH, the objectives of this thesis are to replace the acetylene precursor with biobased precursors in the single-stage CCVD process (continuous injection of catalytic and carbonaceous precursors). In addition, the aim is to understand the influence of precursor type and synthesis conditions on the characteristics of the materials formed on various types of support, and to test their potential for the targeted applications, particularly in the energy field. This thesis demonstrates that biobased precursors can effectively replace acetylene in the growth of VACNTs by CCVD, obtaining materials with similar characteristics (height, mass, density, quality...). In this way, 100 µm mats were obtained from the coupling of ethylene with butanol, replacing the toluene previously used as a ferrocene solvent. These materials gave interesting results in terms of volumetric capacity as supercapacitor electrodes, but also in terms of capacity retention as battery electrodes. In addition, tests on a semi-industrial scale validated the interest of the process, demonstrating the flexibility of the process developed in the laboratory. In addition, more detailed physico-chemical analyses have been carried out to better understand the role of these precursors on VACNT growth in terms of growth activation energy, decomposition in the gas phase and interaction with the substrate (aluminum, stainless steel and copper)
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
Development and characterization of VACNT/MnO2 electrodes and application to supercapacitors
No full textLes travaux de cette thèse ont porté sur l'élaboration, l'optimisation et l'étude d'électrodes composites de nanotubes de carbone verticalement alignés (VACNT) sur un collecteur d'aluminium et modifiés par l'oxyde de manganèse (MnO₂). Les VACNT synthétisés par voir CVD à basse température (580°C:) directement sur le collecteur ont permis d'obtenir des tapis de NTC parfaitement alignés d'une épaisseur allant de 20 à 80 µm et possédant des densités de 10¹¹ NTC.cm² et dont le taux de catalyseur (Fe) est inférieur à 1%. Leur modification par du MnO2 permet d’accroître leur capacité de stockage électrochimique. Afin de réaliser un enrobage optimal des VACNT par le MnO₂, différents précurseurs de l'oxyde ainsi que diverses méthodes(dépôts électrochimiques, chimiques, CVD) ont été utilisées et optimisées. Les composites élaborés ont ensuite été étudiées en tant que matériau d'électrode pour la réalisation de supercondensateurs asymétriques eu milieux aqueux.This thesis was focused on the development, optimization and study of composite electrodes of vertically aligned carbon nanotubes (VACNT) on an aluminum collector and modified with manganese oxide (MnO₂).VACNT were synthesized by a CVD process at low temperature (580° C) directly on the collector. Perfectly aligned CNT forest with a thickness of 20 to 80 μm were obtained with high densities of 10¹¹ NTC.cm² and whose catalyst (Fe) content is less than 1%. Their modification with MnO₂ increase their electrochemical storage capacity. In order to achiew optimal coating of VACNT by MnO₂, different precursors of the oxide and various methods ( electrochemical, chemical, CVD) were used and optimized. Composites were studied as electrode material for the realization of asymmetric supercapacitors in aqueous media. In addition, structurals, morphologicals and electrochemicals analyzes carried out on the different materials allowed a better understanding of the role of the elaboration's conditions on the properties of the VACNT/MnO₂ composites obtained
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