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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Synthesis and applications of new multidentate metallocenic complexes
No full textCe mémoire porte sur l’accès simple et peu coûteux à de nouveaux ligands ferrocéniques aminés et aminophosphinés et leur coordination avec des métaux de transition pour des applications en catalyse homogène.Des métallo-ligands aminés flexibles ont été obtenus et caractérisés après amination réductrice du 1,1’-diformylferrocène. D’autres ligands (N,N) rigides ont été isolés au départ du précurseur du 1,1’-di-tert-butyl-3,3’-diformylferrocène. Des aza-ferrocénophanes ont également été facilement préparés avec ces deux précurseurs carbonylés. Lors de la coordination de ces ligands avec le palladium, un palladacycle original a été isolé et caractérisé par diffraction de rayons X.Des ligands ferrocéniques (N,P) ont été obtenus par trois méthodes: i) ortholithiation de ligands ferrocéniques aminés suivie d’un ajout de chlorophosphine, ii) amination réductrice des ferrocènes formylés substitués ou non en présence d’amine portant une fonction phosphine, iii) substitution directe du ferrocène dilithié par des chlorophosphines comportant un hétérocycle azoté. Leur coordination avec du palladium et du platine a été étudiée. Ces métallo-ligands hybrides ont été impliqués dans des réactions de chlorures d’aryle avec des acides arylboroniques (couplage de Suzuki), ainsi que dans la réaction de Sonogashira avec le couplage de bromures et de chlorures d’aryle avec le phénylacétylèneThis thesis focuses on simple and inexpensive access to new amino and aminophosphine ferrocenyl ligands and their coordination with transition metals for applications in homogeneous catalysis.Flexible amine metallo-ligands were obtained and characterized after reductive amination of 1,1'-diformylferrocene. Other rigid (N,N) ligands were isolated starting from the precursor 1,1'-di-tert-butyl-3, 3'-diformylferrocene. Aza-ferrocenophanes were also easily prepared with these two formyl precursors. During the coordination of these ligands with palladium, a stable and original palladacycle was isolated and characterized by DRX.(N,P) ferrocenyl ligands were obtained by three methods: i) ortholithiation of aminoferrocenyl ligands followed by addition of chlorophosphines, ii) reductive amination of substituted or not formylferrocene in the presence of amine bearing a phosphine function, iii) direct substitution of dilithiated ferrocene by chlorophosphines with a nitrogen-containing heterocycle. Their coordination with palladium and platinum has been studied. These hybrid metallo-ligands have been implicated in the reactions of aryl chlorides to arylboronic acids (Suzuki cross-coupling), as well as in the Sonogashira reaction involving of coupling aryl bromides and chlorides to phenylacetylen
Variations on the Author
Full text link“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
Full text linkWe 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
Activation d'alcynes par les derives du ruthenium. Preparation de complexes vinylidene, acetylure et allenylidene
No full textSIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 83187 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Synthesis, characterisation and complexation of di- and trifunctional hybrid ferrocenylphosphine ligands.
No full textLes composés organométalliques qui contiennent un métal lié à au moins un atome de carbone, sont utilisés dans des domaines très variés de la chimie : par exemple en recherche médicale pour des traitements anticancéreux, dans les réactions catalytiques en tant que catalyseurs ou ligands, en électrochimie pour leur potentiel rédox, en chimie des matériaux pour leurs propriétés optiques ou électroniques. La famille de composés organométalliques centrale de cette thèse est celle du ferrocène pour ses propriétés physiques et chimiques, et en particulier sa robustesse, et la possibilité de multiples substitutions offerte sur ses deux cycles cyclopentadiényle en position « sandwich » autour du fer, la fonctionnalisation dissymétrique de ces anneaux cyclopentadiényle étant un défi majeur.La première partie de cette thèse analyse la bibliographie des synthèses de composés ferrocéniques hybrides phosphorés, et leurs études en tant que ligands en chimie de coordination et en catalyse.La deuxième partie porte sur le développement de deux nouvelles familles de ferrocènes hybrides [acide de Brönsted/base de Lewis] élaboré sur une plateforme ferrocénique préalablement dialkylée à conformation contrainte. La synthèse de ligands de type [PR2/CO2H] et leurs études de complexation ont été réalisées. L’évolution de cette famille par réaction d’amidation a permis d’accéder à de nouveaux ferrocènes plus polaires de type [PR2/CONHCH2SO3NHEt3].La troisième partie traite du développement de ferrocènes hybrides trifonctionnels de type [phosphine/aminoacide]. Différents aminoacides ont été intégrés qui permettent de diversifier les environnements stériques, pouvant ainsi rigidifier les structures de ligands et favoriser divers types de complexation avec des métaux de transition en vue de leur utilisation en catalyse sélective.Organometallic compounds with at least one metal-carbon bond are used in various fields of chemistry: for example, in medical research for anticancer treatments, in catalytic reactions as catalysts or ligands, in electrochemistry for their redox potentials, in materials chemistry for their optical and electronic properties. The principal family of organometallic compounds of this thesis is ferrocene due to its physical and chemical properties particularly its robustness and the possibility of multiple substitutions on cyclopentadienyl ligands, the dissymmetric functionalization of these cyclopentadienyl rings being a major challenge.The first part of this thesis describes the bibliography of syntheses of phosphorus-containing hybrid ferrocene compounds and their studies as ligands in coordination chemistry and catalysis.The second part focuses on the development of two new hybrid ferrocene families [Brönsted acid/Lewis base] on a dialkylated ferrocene platform with constrained conformation. More precisely, the synthesis and complexation of ligands type [PR2/CO2H] and [PR2/CONHCH2SO3NHEt3] have been done. Interestingly, the evolution of the former ligand type by amidation allows us to have an access to more polar ferrocene families (latter type).The third part investigates the development of trifunctional hybrid ferrocenes type [phosphine/aminoacid]. Various aminoacids have been introduced to diversify steric environments, lock the ligand structures and favor various modes of complexation with transition metals to use in selective catalysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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