1,721,066 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
De la synthèse de procyanidines à leur quantification dans les baies de raisins et le vin
No full textLes flavanols et leurs oligomères, les procyanidines, sont des composés phénoliques biosynthétisés dans les baies de raisin, dont ils sont extraits pendant la vinification. Une meilleure compréhension de leur évolution pendant la maturation du raisin, la vinification et le vieillissement du vin est importante du fait de leur responsabilité dans beaucoup des propriétés organoleptiques du vin (couleur, amertume et astringence). Plusieurs procyanidines ont été obtenues par une méthode de synthèse permettant de contrôler aussi bien la régio- et la stéréosélectivité de la liaison interflavane que le degré d’oligomérisation. Cette méthode a pu être élargie à la synthèse de procyanidines galloylées. L’étape de couplage, qui restait l’étape limitante de cette synthèse, a pu être améliorée par l’utilisation de la catalyse à l’or. Ces composés ont ensuite été utilisés comme standards afin de les identifier et les quantifier dans du raisin et des vins par chromatographie liquide haute performance. L’étude des intéractions supramoléculaires des composés galloylés a été évaluée par RMN DOSY. En parallèle de ces études, un nouveau composé indolique, possédant un motif glucose dans sa structure, a été identifié et caractérisé pour la première fois dans les vins rouges.Flavanols and their oligomers, procyanidins, are phenolics compounds biosynthetized in grapes, from which they are extrated during winemaking As they contribute so much to the organoleptics properties of the wine (color, bitterness and astringency), a better comprehension of their evolution during grapes maturation, winemaking and ageing of the wine is particulary important. Several procyanidines were obtained by a synthesis method which allows to control as well the interflavan regio- and stereoselectivity as the degree of oligomerization. This method was extended to the synthesis of galloylated procyanidins. The stage of coupling, which was a limiting stage of this synthesis, could be improved by the use of gold III catalysis. These compounds were then used as standards in order to identify and quantify them in grapes and wines by high performance liquid chromatography. The supramolecular properties of galloylated procyanidins were investigated by NMR DOSY. In parallel to these studies, a new indolic compound bearing a glucose moiety, has been identified and characterized for the first time in red wine
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
Approche moléculaire de l'astringence par l'étude des interactions entre les tanins du vin et les protéines de la salve
No full textLors de la dégustation des vins rouges, une sensation de sécheresse nommée astringence peut avoirlieu. Cette sensation est causée par l’interaction des tanins du vin et des protéines salivairescorrespondant à un phénomène d’une extrême complexité. Cinq tanins représentatifs des vins B1, B2,B3, B4 et C2, et trois peptides représentatifs des protéines de la salive IB714, IB937 et l’histatine 3 ontété synthétisés et étudiés par des approches de physico-chimie et de biologie structurale telles que laRMN, le dichroïsme circulaire et la modélisation moléculaire. Après une étude structurale, lesparamètres de l’interaction ont été déterminés pour l’ensemble des systèmes permettant de construiredes échelles d'affinités montrant l’influence de la structure tridimensionnelle des tanins et de leurnature (degrés de polymérisation), de la longueur du peptide et la meilleure affinité des tanins pour lesPRP comparées aux PRH. Ces études ont également mis en évidence l’importance de la concentrationen tanin sur le phénomène de précipitation. En dessous de leur CMC, les tanins forment des colloïdesavec les peptides par le biais de liaisons hydrogènes, et au-dessus de leur CMC, les interactionshydrophiles restent préférentielles mais des interactions hydrophobes interviennent dans un deuxièmetemps.During tasting of red wines, a sensation of dryness named astringency may occur. This sensation iscaused by the interaction between wine tannins and salivary proteins corresponding to an extremelycomplex phenomenon. Five representative wine tannins B1, B2, B3, B4 and C2, and threerepresentative peptides IB714, IB937 and histatin 3 from saliva were synthesized and studied byphysical chemistry and biology structural tools, such as NMR, circular dichroism and molecularmodeling. After a structural study, the parameters of the interaction were determined for all systemsallowing to build affinities scales, showing the influence of three-dimensional structure of tannins andtheir nature (degree of polymerization), the influence of the peptide length and the higher affinity oftannins for PRP than HRP. These studies have also highlighted the importance of concentration oftannin on the phenomenon of precipitation. Below their CMC, tannins bind specifically to salivaryproteins. Above the CMC, the specific interactions are still present, but tannins can also form micellesand create hydrophobic interactions
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
Alzheimer's disease and the role of polyphenols in new therapeutic strategies : multi-technical analysis of "polyphenols-peptides Tau" interactions
No full textLa Maladie d’Alzheimer est caractérisée par la formation de dégénérescences neurofibrillaires, constituées de protéine Tau anormalement hyperphosphorylée et agrégée. De nombreuses études traitent de possibles stratégies thérapeutiques basées sur l’inhibition de cette polymérisation, et présentent les effets bénéfiques de certaines molécules dont les polyphénols, mais les résultats obtenus jusque là, manquent de données au niveau moléculaire. Ainsi, après avoir synthétisé, une banque de polyphénols de structures différentes, et 3 peptides représentatifs de la région P de phosphorylation de Tau, c’est en suivant une stratégie combinant la RMN et la modélisation moléculaire, que nous avons évalué les paramètres dynamiques du complexe formé. Ce projet nous a apporté des informations en termes d’affinité, et de relations structure/activité et ainsi, de mieux appréhender les mécanismes d’interactions intervenant dans l’agrégation de Tau par les polyphénols.Alzheimer's disease is characterized by the formation of neurofibrillary tangles constituted by abnormally hyperphosphorylated and aggregated Tau protein. Many studies deal with potential therapeutic strategies based on the inhibition of this polymerization, and show the beneficial effects of some molecules like polyphenols, but the obtained so far results show a lack of data at the molecular level. Thus, after the synthesis of, a library of polyphenols with different structures, and 3 representative peptides of the P2 phosphorylation Tau region, by following a strategy combining NMR and molecular modeling, we have evaluated dynamic parameters of the formed complex. This project has provided us informations in terms of affinity, and structure / activity relationships, and leading us to a better understanding of the mechanisms led to better understand the mechanisms involved in the aggregation Tau inhibition phenomena by polyphenols
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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