1,720,960 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
Révéler des voies électrochimiques compétitives aux échelles nanométriques par imagerie optique operando
No full textAvec l'augmentation de la demande énergétique mondiale et les problèmes environnementaux liés à l'utilisation d'énergies fossiles, une part plus importante du mix énergétique doit être laissée aux énergies renouvelables telles que le solaire ou l'éolien. Cependant, du fait de leur intermittence, une part trop importante de ces dernières pourrait provoquer des instabilités sur le réseau. Pour remédier à ce problème, une solution consiste à stocker l'énergie sous forme chimique, dans des batteries (Li-ion le plus souvent) ou des molécules telles que l'hydrogène, afin de la restituer lors des pics de consommation. Les ressources en Li et en Pt (catalyseur utilisé pour la production d'hydrogène) étant limitées, de nombreux scientifiques se sont mis à la recherche de nouveaux matériaux. Des dizaines sont proposés tous les jours, mais il est difficile de discerner les candidats intéressants en raison de la complexité des électrodes et de l'absence de tests standardisés. Dans ce contexte, l'objectif de cette thèse est de coupler la microscopie optique super-localisée avec des sondes électrochimiques locales afin d'évaluer, à l'échelle nanométrique, les performances intrinsèques de matériaux pour l'énergie. Cela permet également d'éclairer les mécanismes sous-jacents souvent extrêmement complexes. Dans un premier temps, le mécanisme de l'électrodéposition de nanoparticules (NPs) de Ni est étudié et révèle, en plus de NPs de Ni, la présence de NPs de Ni(OH)2. Ceci est dû à la compétition avec la réduction de l'eau qui basifie localement le milieu. Une analyse quantitative de la croissance des NPs de Ni révèle qu'environ 75% du pic de courant attribué à l'électrodéposition est en réalité lié à la catalyse de la réduction de l'eau par les NPs de Ni. Par la suite, l'observation de la croissance d'un halo de Ni(OH)2 autour des NPs de Ni permet de quantifier leur activité catalytique à l'échelle de NPs individuelles et de mettre en évidence un effet synergique entre Ni et Ni(OH)2. Dans un deuxième temps, la microscopie optique est utilisée pour sonder la conversion de microparticules de matériaux de batterie. Une première étude met en évidence le mécanisme de stockage de charge des batteries aqueuses Zn-MnO2 ainsi que le rôle crucial de l'hydroxysulfate de Zn dans la stabilisation du potentiel. En couplant microscopie optique et microscopie électrochimique à balayage, la dynamique spatio-temporelle de la conversion de particules d'hexacyanoferrate de Cu (utilisées comme solid booster dans les batteries redox flow) est ensuite mise en évidence à l'échelle sub-particulaire. Dans l'ensemble, cette thèse démontre que la microscopie optique est particulièrement adaptée à l'analyse operando de mécanismes électrochimiques complexes grâce à sa résolution temporelle importante, sa résolution spatiale importante, sa faible invasivité et grâce à l'information chimique que peuvent contenir ses images.With the increase in global energy demand and the environmental problems associated with the use of fossil fuels, renewable energies such as solar and wind power need to play a greater role in the energy mix. However, because of their intermittency, too large a share of renewables could cause instability on the grid. One solution to this problem is to store energy in chemical form, in batteries (usually Li-ion) or molecules such as hydrogen, so that it can be released when consumption peaks. With limited resources of Li and Pt (the catalyst used to produce hydrogen), many scientists are looking for alternative materials. Dozens are proposed every day, but it is difficult to discern the interesting candidates because of the complexity of the electrodes and the absence of standardised testing protocols. In this context, the aim of this thesis is to couple super-localized optical microscopy with local electrochemical probes in order to measure, at the nanoscale, the intrinsic performance of materials for energy applications. This will also shed light on the underlying mechanisms, which are often extremely complex. Firstly, the electrodeposition mechanism of Ni nanoparticles (NPs) is studied and reveals the presence of Ni(OH)2 NPs in addition to Ni NPs. This is due to competition with the reduction of water, which locally basifies the medium. A quantitative analysis of the growth of the Ni NPs reveals that around 75% of the current peak attributed to electrodeposition is actually linked to catalysis of water reduction by the Ni NPs. Subsequently, observation of the growth of a Ni(OH)2 halo around the Ni NPs enables us to quantify their catalytic activity at the individual NP level and to demonstrate a synergistic effect between Ni and Ni(OH)2. Secondly, optical microscopy is used to probe the conversion of battery material microparticles. An initial study highlights the charge storage mechanism of aqueous Zn-MnO2 batteries and the crucial role of Zn hydroxide sulphate in stabilising the potential. By coupling optical microscopy and scanning electrochemical microscopy, the spatio-temporal dynamics of the conversion of Cu hexacyanoferrate particles (used as solid boosters in redox flow batteries) is also highlighted at the sub-particle scale. Overall, this thesis demonstrates that optical microscopy is particularly well suited to the operando analysis of complex electrochemical mechanisms thanks to its high temporal resolution, high spatial resolution, low invasiveness, and thanks to the chemical information that its images can contain
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
Révéler des voies électrochimiques compétitives aux échelles nanométriques par imagerie optique operando
No full textWith the increase in global energy demand and the environmental problems associated with the use of fossil fuels, renewable energies such as solar and wind power need to play a greater role in the energy mix. However, because of their intermittency, too large a share of renewables could cause instability on the grid. One solution to this problem is to store energy in chemical form, in batteries (usually Li-ion) or molecules such as hydrogen, so that it can be released when consumption peaks. With limited resources of Li and Pt (the catalyst used to produce hydrogen), many scientists are looking for alternative materials. Dozens are proposed every day, but it is difficult to discern the interesting candidates because of the complexity of the electrodes and the absence of standardised testing protocols. In this context, the aim of this thesis is to couple super-localized optical microscopy with local electrochemical probes in order to measure, at the nanoscale, the intrinsic performance of materials for energy applications. This will also shed light on the underlying mechanisms, which are often extremely complex. Firstly, the electrodeposition mechanism of Ni nanoparticles (NPs) is studied and reveals the presence of Ni(OH)2 NPs in addition to Ni NPs. This is due to competition with the reduction of water, which locally basifies the medium. A quantitative analysis of the growth of the Ni NPs reveals that around 75% of the current peak attributed to electrodeposition is actually linked to catalysis of water reduction by the Ni NPs. Subsequently, observation of the growth of a Ni(OH)2 halo around the Ni NPs enables us to quantify their catalytic activity at the individual NP level and to demonstrate a synergistic effect between Ni and Ni(OH)2. Secondly, optical microscopy is used to probe the conversion of battery material microparticles. An initial study highlights the charge storage mechanism of aqueous Zn-MnO2 batteries and the crucial role of Zn hydroxide sulphate in stabilising the potential. By coupling optical microscopy and scanning electrochemical microscopy, the spatio-temporal dynamics of the conversion of Cu hexacyanoferrate particles (used as solid boosters in redox flow batteries) is also highlighted at the sub-particle scale. Overall, this thesis demonstrates that optical microscopy is particularly well suited to the operando analysis of complex electrochemical mechanisms thanks to its high temporal resolution, high spatial resolution, low invasiveness, and thanks to the chemical information that its images can contain.Avec l'augmentation de la demande énergétique mondiale et les problèmes environnementaux liés à l'utilisation d'énergies fossiles, une part plus importante du mix énergétique doit être laissée aux énergies renouvelables telles que le solaire ou l'éolien. Cependant, du fait de leur intermittence, une part trop importante de ces dernières pourrait provoquer des instabilités sur le réseau. Pour remédier à ce problème, une solution consiste à stocker l'énergie sous forme chimique, dans des batteries (Li-ion le plus souvent) ou des molécules telles que l'hydrogène, afin de la restituer lors des pics de consommation. Les ressources en Li et en Pt (catalyseur utilisé pour la production d'hydrogène) étant limitées, de nombreux scientifiques se sont mis à la recherche de nouveaux matériaux. Des dizaines sont proposés tous les jours, mais il est difficile de discerner les candidats intéressants en raison de la complexité des électrodes et de l'absence de tests standardisés. Dans ce contexte, l'objectif de cette thèse est de coupler la microscopie optique super-localisée avec des sondes électrochimiques locales afin d'évaluer, à l'échelle nanométrique, les performances intrinsèques de matériaux pour l'énergie. Cela permet également d'éclairer les mécanismes sous-jacents souvent extrêmement complexes. Dans un premier temps, le mécanisme de l'électrodéposition de nanoparticules (NPs) de Ni est étudié et révèle, en plus de NPs de Ni, la présence de NPs de Ni(OH)2. Ceci est dû à la compétition avec la réduction de l'eau qui basifie localement le milieu. Une analyse quantitative de la croissance des NPs de Ni révèle qu'environ 75% du pic de courant attribué à l'électrodéposition est en réalité lié à la catalyse de la réduction de l'eau par les NPs de Ni. Par la suite, l'observation de la croissance d'un halo de Ni(OH)2 autour des NPs de Ni permet de quantifier leur activité catalytique à l'échelle de NPs individuelles et de mettre en évidence un effet synergique entre Ni et Ni(OH)2. Dans un deuxième temps, la microscopie optique est utilisée pour sonder la conversion de microparticules de matériaux de batterie. Une première étude met en évidence le mécanisme de stockage de charge des batteries aqueuses Zn-MnO2 ainsi que le rôle crucial de l'hydroxysulfate de Zn dans la stabilisation du potentiel. En couplant microscopie optique et microscopie électrochimique à balayage, la dynamique spatio-temporelle de la conversion de particules d'hexacyanoferrate de Cu (utilisées comme solid booster dans les batteries redox flow) est ensuite mise en évidence à l'échelle sub-particulaire. Dans l'ensemble, cette thèse démontre que la microscopie optique est particulièrement adaptée à l'analyse operando de mécanismes électrochimiques complexes grâce à sa résolution temporelle importante, sa résolution spatiale importante, sa faible invasivité et grâce à l'information chimique que peuvent contenir ses images
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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