1,721,130 research outputs found
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
Functional genomics in Candida albicans: tackling drug resistance and morphology
No full textThe human fungal pathogen Candida albicans is a diploid organism that lacks a complete sexual cycle, thus making functional genetics challenging. Consequently, linking a function to a gene often relies on predictions from other model organisms. In this thesis, I have explored different genetic strategies to address two important aspects of the biology of C. albicans, drug resistance and morphology, which are associated with virulence. Using a reverse genetics approach based on the model Saccharomyces cerevisiae, I first identify and validate a new drug target in C. albicans. Next, I use forward genetics screening directly in the pathogen to identify genes regulating morphology by showing that the Arp2/3 complex is required for the yeast-to-hyphae switch as well as virulence. Lastly, I follow up on the Arp2/3 complex and demonstrate how this fungus can be used to study some unique cell biological aspects regarding actin dynamics and endocytosis. Collectively, this thesis illustrates how various genomic techniques can be applied to understand different aspects of this human fungal pathogen.La levure pathogène Candida albicans est un organisme diploïde n'ayant pas de cycle sexuel complet, ce qui rend difficile la génétique fonctionnelle. Par conséquence, la liaison d'un gène à une fonction repose souvent sur des prévisions à partir d'autres organismes modèles. Dans cette thèse, j'ai exploré différentes stratégies génétiques afin d'étudier deux aspects importants de la biologie de C. albicans, la résistance aux médicaments et la morphologie, qui est associée à la virulence. Avec l'aide d'une approche de génétique inverse basée sur l'organisme modèle Saccharomyces cerevisiae, j'ai d'abord identifié et validé une nouvelle cible thérapeutique chez C. albicans. Ensuite, j'ai utilisé la génétique directe de C. albicans pour identifier des gènes qui régulent sa morphologie. Ceci m'a permis de montrer que le complexe Arp2/3 est requis pour la formation des hyphes ainsi que la virulence. Enfin, je me suis concentré sur le complexe Arp2/3 et j'ai démontré que cette levure peut être utilisée pour étudier certains aspects unique de sa biologiques cellulaire, en particulier, la dynamique de l'actine et l'endocytose. Collectivement, cette thèse montre comment diverses techniques de génétique et de génomique peuvent être appliquées afin de comprendre différents aspects de ce pathogène fongique humain
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
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
Transcriptional regulation of carbohydrate metabolism in «Candida albicans»
No full textGlycolysis is a key metabolic pathway that is fundamental to the ability of organisms to assimilate carbon sources. Transcriptional control is a significant mechanism of regulation of glycolysis, although the transcription factors controlling this process in eukaryotes are largely unknown outside the facultative anaerobe Saccharomyces cerevisiae. Since S. cerevisiae exhibits a uniquely fermentative lifestyle due to an evolutionarily-driven glucose repression circuit, carbohydrate regulation needs to be studied in aerobic species such the facultative aerobe Candida albicans. This human pathogen is known to rely on glycolysis for the progression of systemic infections. In this thesis I 1) validate constructs that can be used for location profiling in C. albicans, 2) demonstrate the conservation of protein-protein interactions between the SAGA chromatin remodeling complex and Gal4p even though Gal4p has altered its role within the Saccharomycotina subphylum, and 3) characterize two key glycolytic regulators in C. albicans, demonstrating their importance for fermentative growth and virulence. My findings further illustrate the plasticity of regulatory circuits and highlight differences in the regulation of carbohydrate metabolism between S. cerevisiae and aerobic eukaryotic cells.La glycolyse est une voie métabolique fondamentale chez de nombreux organismes pour l'assimilation de carbones provenant de différentes sources. Bien que la régulation transcriptionelle représente le premier régulateur, et sûrement le principal, sa coordination est largement méconnue en dehors de la levure model Saccharomyces cerevisiae. Toutefois, cette levure anaérobique facultative a acquit au cours de son évolution des capacités fermentatrices uniques résultantes, et entraînées par, une diminution du glucose environnant. Contrastant avec S. cerevisiae, la régulation de la voie métabolique de carbohydrates est largement méconnue chez les organismes aérobic facultatif tel que Candida albicans. L'étude de la glycolyse chez ce pathogène opportuniste humain revête aussi un intérêt supplémentaire puisqu'il a été démontré que cette voie métabolique était requise lors des infections systémiques. Dans le présent mémoire, je 1) validerais l'utilisation d'outils permettant la localisation génomique chez C. albicans, 2) prouverais les interactions protéiques entre le complexe de remodelage de la chromatine SAGA et le facteur de transcription Gal4p et ce malgré le recablage fonctionnel de Gal4p chez les Saccharomycètes, et 3) définirais deux nouveaux régulateur de la glycolyse et démontrerais leurs importance dans la fermentation et la virulence de C. albicans. Finalement, l'ensemble de ces résultats illustrent les recablage transcriptionel et leurs importances évolutives tout en soulignant les différentes approches utilisées chez les eucaryotes pour réguler une voie métabolique aussi fondamental que la glycolyse. f
Morphogenesis of opaque form «Candida albicans» cells
No full textABSTRACT We followed the localization of GFP-tagged myosin I (Myo5), septin (Cdc12) and rhodamin-stained actin during bud and shmoo formation in opaque-phase cells of Candida albicans, and monitored the mating-associated processes of cell fusion, zygote budding, septum formation, daughter cell development and the dynamics of nuclear migration and division. The localization of Myo5p, Cdc12p and actin during budding in opaque and white cells is similar. In pheromone-stimulated cells, these proteins localize in shmoos in patterns consistent with hyphal formation in white-phase cells. MTLa cells generate shmoos 5-7 hours earlier than MTLα cells in mixed populations. In the daughter cell generated after mating, Cdc12p, Myo5p and actin localize as they do under vegetative budding conditions. Intriguingly, isogenicity for the mating type locus is involved in the positioning of the nuclear division; in MTLa cells the nucleus divides within the mother cell up to 70% of the time, rather than across the mother-bud neck.RÉSUMÉ Nous avons déterminé la localisation de l'actine ainsi que de la myosine I (Myo5) et de la septine (Cdc12) modifiées avec la protéine fluorescente verte (GFP) chez Candida albicans en phase opaque (reproductive) et blanche (végétative). Plus particulièrement, nous avons porté notre attention sur les processus associé à la reproduction tel le bourgeonnement et l'expansion cellulaire (shmoo), la conjugaison et la fusion cellulaire, le bourgeonnement et le développement des zygotes (cellules -filles issues de la conjugaison). Nous avons aussi observé la configuration subcellulaire de Myo5p, Cdc12p et de l’actine lors de la migration et de la division nucléaire en phase blanche. Que ce soit en phase opaque ou en phase blanche, la localisation de Myo5p, Cdc12p et de l'actine reste similaire lors du bourgeonnement. Lors d’une stimulation à la phéromone, en phase opaque, ces trois protéines ont le même patron d’organisation cellulaire que lors de la formation d'hyphes en phase blanche. Les cellules de type MTLa produisent des shmoo entre 5 et 7 heures plus tôt que les cellules de type MTLα dans une population mixte. Dans les zygotes, Cdc12p, Myo5p et l'actine ont la même localisation que celle observée dans les cellule-filles issues du bourgeonnement en mode végétatif. Étonnamment, l'isogénicité du locus génétique déterminant le type sexuel de la cellule influence la position du noyau lors de la division; Ainsi, dans 70% des cas, le noyau des cellules de type MTLa se divise à l'intérieur de la cellule-mère plutôt qu'au travers du col entre la cellule-mère et le bourgeon
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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