1,721,254 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
Homogeneous and heterogeneous Fenton and photo-Fenton processes : impact of iron complexing agent ethylenediamine-N,N'-disuccinic acid (EDDS)
No full textDans cette étude nous avons utilisé le bisphénol A (BPA) comme polluant modèle pour analyser l’efficacité des différents processus de Fenton et photo-Fenton mis en place. Dans un premier temps nous avons étudié le processus de Fenton en présence du complexe Fe(III)-EDDS utilisé comme source de fer. Différents paramètres physico-chimiques (concentrations en H2O2, Fe(III)-EDDS, O2 et le pH) ont été testés afin d’optimiser l’efficacité du système en termes de dégradation du BPA. Parallèlement, le même type d’étude a été mené en présence de lumière (de 300 à 450 nm) afin d’étudier le processus de photo-Fenton. Dans les 2 cas nous avons mis en évidence un effet du pH peu commun puisque la dégradation de BPA est plus rapide et importante plus le pH est élevé dans une gamme allant de 3,0 à 9,0. Dans le but de comprendre le mécanisme mis en jeu des expériences d’inhibition de radicaux (·OH et HO2●/O2●-) ont été réalisées. Une des conclusions importantes de ce travail est que dans les deux systèmes le complexe Fe(III)-EDDS joue un rôle très positif pour la dégradation du BPA. De plus, nous avons également montré que ces processus étaient très efficaces pour des pH proches de la neutralité et faiblement basiques. La comparaison avec d’autres complexant du fer (EDTA, citrate, oxalate) montre qu’en présence du complexe Fe(III)-EDDS nous obtenons l’efficacité la plus importante. Ce résultat et le fait que les processus soient très efficaces à pH neutre ou faiblement basiques montrent que le complexe Fe(III)-EDDS est vraiment une source de fer très prometteuse dans les processus de Fenton et photo-Fenton. Dans une troisième partie nous avons regardé l’effet d’EDDS dans un système hétérogène en présence de Goethite comme source de fer. Dans ce chapitre il a été mis en évidence que l’EDDS inhibe le processus de Fenton, EDDS s’adsorbe fortement à la surface et limite la réactivité de H2O2 avec la surface de la Goethite. Par contre dans le processus de photo-Fenton, EDDS augmente l’efficacité de dégradation du BPA à pH proche de la neutralité et à faible concentration en H2O2.In this study we used the bisphenol A (BPA) as a model pollutant to analyse the efficiency of the Fenton and photo-Fenton processes. In the first part of the thesis, we studied the Fenton process in the presence of the complex Fe(III)-EDDS used as iron source. Different physicochemical parameters (concentrations of H2O2, Fe(III)-EDDS, O2 and pH) were tested with the goal to optimized the efficiency of the system in terms of BPA degradation. In the same time, the same kind of experiments were performed in the presence of light (emission from 300 to 450 nm) to study the photo-Fenton process. In the two cases (Fenton and photo-Fenton), we observed a strong and not usual pH effect. Indeed, the degradation of BPA is faster and more important when the pH is higher in the range between 3.0 and 9.0. To understand the mechanisms involved in such processes, some inhibition experiments of radicals (·OH and HO2●/O2●-) were performed. One of the most important conclusion of this research work is that the Fe(III)-EDDS complex plays a very positive role for the degradation of BPA. Moreover, in the presence of Fe(III)-EDDS the Fenton and photo-Fenton processes are very efficient in neutral and slightly basic pH. The comparison with other iron complexes (EDTA,citrate, oxalate) shows that in the presence of Fe(III)-EDDS complex we obtained the better efficiency for the degradation of BPA. This result and the fact that Fe(III)-EDDS is efficient until pH 9.0 show that Fe(III)-EDDS complex is really a promising iron source for the Fenton and photo-Fenton processes. In a third part, we studied the effect of EDDS in a heterogeneous system in the presence of Goethite as an iron source. In this chapter, we demonstrated that the presence of EDDS is detrimental for the Fenton process and leads to an inhibition of the process. In fact, EDDS is strongly adsorbed at the surface of the Goethite and avoid the reactivity of H2O2 at the Goethite surface. On the contrary, in the photo-Fenton process EDDS increases the efficiency of the BPA degradation for pHs near 7.0 and at low H2O2 concentrations
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
Physico-chemistry of the cloud aqueous phase sampled at the top of the puy de Dôme : characterisation and photochemical reactivity
No full textLe milieu nuageux est un milieu complexe au sein duquel un grand nombre d’espèces chimiques peuvent être transformées. Dans ce cadre, la caractérisation chimique et la réactivité photochimique de la phase aqueuse des nuages ont été étudiées. La caractérisation chimique de la phase aqueuse des nuages a permis de montrer que les masses d’air échantillonnées au sommet du puy de Dôme sont majoritairement sous trois influences distinctes, à savoir océanique, continentale et anthropique. La distribution des paramètres physicochimiques et des composés inorganiques est dépendante du type de masses d’air échantillonnées. De plus, la quantification des acides carboxyliques et des aldéhydes a permis de mettre en avant la complexité de la matière organique avec la présence d’une multitude de composés encore non identifiés. L’étude de la réactivité photochimique de la phase aqueuse des nuages a également été réalisée, montrant que la capacité photooxydante de la phase aqueuse des nuages ainsi que les vitesses de dégradation de différentes espèces chimiques sont plus importantes pour les masses d’air polluées. Pour la première fois, des vitesses de photoproduction des radicaux hydroxyles ont été évaluées dans la phase aqueuse des nuages, montrant que les ions nitrates et le peroxyde d’hydrogène sont des sources photochimiques majeures des radicaux hydroxyles (représentant jusqu’à 80 % de leur photoproduction totale).Clouds represent complex media where many species can be transformed. In order to characterize the chemical composition of cloud water and to better understand the processes involved in the transformations of these species, the characterization and the photoreactivity of cloud water were studied. The characterization of cloud water showed that air masses sampled at the puy de Dôme station can be subject to different influences (marine, continental and anthropogenic). The distribution of the physicochemical parameters and of inorganic compounds was different for each kind of air masses. Moreover, the quantification of carboxylic acids and aldehydes showed the complexity of the organic matter contained in cloud water, with the presence of many unknown organic compounds. The photoreactivity of cloud water was also studied, showing that the oxidizing capacity of cloud water and the degradation rate of organic compounds were higher in polluted air masses. For the first time, hydroxyl radical formation rates were determined in cloud water sampled at the puy de Dôme station, showing that nitrate ions and hydrogen peroxide are among the main sources of hydroxyl radicals (contributing up to 80 % of their total photoformation)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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