1,720,970 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
Développement de méthodes géo-électriques pour la caractérisation des processus de dissolution et de précipitation en contexte carbonaté
No full textPrecipitation and dissolution of calcite are key processes in carbonate rocks and being able to monitor them in situ is a major issue. Hydrogeophysical methods are based on the development of appropriate geophysical techniques for monitoring hydrological and biogeochemical processes in a non-intrusive and low-cost manner. Among the existing techniques, electrical methods have already proven their ability to monitor such processes. For this reason, the methods of self-potential (SP) and spectral induced polarization (SIP) were chosen to investigate the processes of dissolution and precipitation of calcite. SP is a passive technique consisting in measuring the natural electric field generated by water flows and concentration gradients, while SIP is an active method measuring the complex electrical conductivity at low frequencies (mHz-kHz). Its real and imaginary components can be related respectively to the microstructure and surface state of the minerals constituting it. This thesis presents experimental and theoretical developments in order to improve the interpretation of SP and SIP methods. A new electrical conductivity model is developed and shows a good fit with the numerical results of dissolution and precipitation. Remarkable SP data have been obtained and could be quantitatively linked through reactive transport modeling. The SIP results provide further insights into the mechanisms responsible for the polarization variations caused by the reactivity of calcite.La précipitation et la dissolution de la calcite sont des processus primordiaux dans les roches carbonatées et le fait de pouvoir les surveiller in situ est un enjeu majeur. Les méthodes hydrogéophysiques sont fondées sur le développement de techniques géophysiques appropriées pour le suivi des processus hydrologiques et biogéochimiques de manière non-intrusive et à faible coût. Parmi les techniques existantes, les méthodes électriques ont déjà prouvé leur capacité à surveiller de tels processus. Pour cette raison, les méthodes du potentiel spontané (PS) et de la polarisation provoquée spectrale (PPS) ont été choisies pour investiguer les processus de dissolution et de précipitation de la calcite. La PS est une technique passive consistant à mesurer le champ électrique naturel généré par les flux d’eau et les gradients de concentration, tandis que la PPS est une méthode active mesurant la conductivité électrique complexe aux basses fréquences (mHz-kHz). Ses composantes réelle et imaginaire peuvent être reliées respectivement à la microstructure et à l’état de surface des minéraux le constituant. Cette thèse présente des développements expérimentaux et théoriques afin d'améliorer l’interprétation des méthodes PS et PPS. Un nouveau modèle de conductivité électrique est développé et montre un bon ajustement avec les résultats numériques de dissolution et de précipitation. Des données PS remarquables ont été obtenues et ont pu être reliées quantitativement grâce à de la modélisation de transport réactif. Les résultats PPS nourrissent la réflexion sur les mécanismes responsables des variations de polarisation engendrés par la réactivité de la calcite
Développement de méthodes géo-électriques pour la caractérisation des processus de dissolution et de précipitation en contexte carbonaté
No full textPrecipitation and dissolution of calcite are key processes in carbonate rocks and being able to monitor them in situ is a major issue. Hydrogeophysical methods are based on the development of appropriate geophysical techniques for monitoring hydrological and biogeochemical processes in a non-intrusive and low-cost manner. Among the existing techniques, electrical methods have already proven their ability to monitor such processes. For this reason, the methods of self-potential (SP) and spectral induced polarization (SIP) were chosen to investigate the processes of dissolution and precipitation of calcite. SP is a passive technique consisting in measuring the natural electric field generated by water flows and concentration gradients, while SIP is an active method measuring the complex electrical conductivity at low frequencies (mHz-kHz). Its real and imaginary components can be related respectively to the microstructure and surface state of the minerals constituting it. This thesis presents experimental and theoretical developments in order to improve the interpretation of SP and SIP methods. A new electrical conductivity model is developed and shows a good fit with the numerical results of dissolution and precipitation. Remarkable SP data have been obtained and could be quantitatively linked through reactive transport modeling. The SIP results provide further insights into the mechanisms responsible for the polarization variations caused by the reactivity of calcite.La précipitation et la dissolution de la calcite sont des processus primordiaux dans les roches carbonatées et le fait de pouvoir les surveiller in situ est un enjeu majeur. Les méthodes hydrogéophysiques sont fondées sur le développement de techniques géophysiques appropriées pour le suivi des processus hydrologiques et biogéochimiques de manière non-intrusive et à faible coût. Parmi les techniques existantes, les méthodes électriques ont déjà prouvé leur capacité à surveiller de tels processus. Pour cette raison, les méthodes du potentiel spontané (PS) et de la polarisation provoquée spectrale (PPS) ont été choisies pour investiguer les processus de dissolution et de précipitation de la calcite. La PS est une technique passive consistant à mesurer le champ électrique naturel généré par les flux d’eau et les gradients de concentration, tandis que la PPS est une méthode active mesurant la conductivité électrique complexe aux basses fréquences (mHz-kHz). Ses composantes réelle et imaginaire peuvent être reliées respectivement à la microstructure et à l’état de surface des minéraux le constituant. Cette thèse présente des développements expérimentaux et théoriques afin d'améliorer l’interprétation des méthodes PS et PPS. Un nouveau modèle de conductivité électrique est développé et montre un bon ajustement avec les résultats numériques de dissolution et de précipitation. Des données PS remarquables ont été obtenues et ont pu être reliées quantitativement grâce à de la modélisation de transport réactif. Les résultats PPS nourrissent la réflexion sur les mécanismes responsables des variations de polarisation engendrés par la réactivité de la calcite
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
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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