1,720,997 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
Characterisation of adipose-specific partial deletion of hormone-sensitive lipase during obesity
No full textObesity is a global pandemic, and the rate of mortality due to associated pathologies, such as type 2 diabetes (T2D), is increasing every year. One of the most substantiated causes of obesity-induced T2D concerns the high amount of fatty acids (FA) delivered in the blood by a hypertrophic adipocyte. FA do not oxidize and therefore are accumulated in non-adipose organs, leading to insulin resistance (IR) (Large et al. 1998). Therefore, the study of lipid metabolism- related enzymes becomes increasingly important. Among them the lipolytic pathway and notably hormone-sensitive lipase (HSL), is the cornerstone of functional fat cell maintenance (Girousse et al. 2013). We attempted to advance in the development of a new mouse model characterized by a lipid specific HSL happloinsufficiency it order to progress in the study of this lipase. We have validated the model by obtaining mice with nearly half deletion of HSL specific to adipose tissues. Nevertheless, the tolerance tests results do not show noticeable differences between control and study group. Such genetic modification do not seem to have systemic metabolic effects
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Nuclear hormone-sensitive lipase and TGFbeta signaling in adipocyte
No full textLe travail présenté dans cette thèse de doctorat s'intéresse à l'adipocyte, la cellule prototypique du tissu adipeux spécialisée dans le métabolisme. Mon travail de thèse a d'abord été dédié au développement et à l'utilisation de modèles de culture d'adipocytes. Une revue publiée détaille les modèles d'études in vitro permettant l'étude de la biologie de l'adipocyte. Elle délimite les avantages et inconvénients des différentes techniques de maintien en survie d'adipocytes ex vivo et des modèles de culture cellulaire de progéniteurs. Cependant, ceux-ci ne récapitulent à l'heure actuelle que partiellement le phénotype de l'adipocyte mature retrouvé in vivo. Un premier objectif de ma thèse a été dès lors de développer un modèle de culture de progéniteurs adipocytaires murins en 3D, dans le but de favoriser leur différenciation en comparaison des cultures conventionnelles en 2D. Dans ces cultures de sphéroïdes, nous obtenons des adipocytes au phénotype plus mature, comme en témoigne la formation d'une gouttelette lipidique uniloculaire et une augmentation de l'expression génique des différents marqueurs de l'adipocyte mature. Ces travaux ont été inclus dans une publication commune avec des chercheurs du Karolinska Institute de Stockholm, qui ont développé un modèle similaire à partir de progéniteurs humains. Le principal objectif de mes travaux de thèse a eu pour but de caractériser un nouveau rôle de la lipase hormono-sensible (LHS) dans le contrôle du phénotype et du métabolisme de l'adipocyte. Cette lipase a initialement été identifiée comme enzyme catalysant l'hydrolyse des triglycérides adipocytaires, une voie catabolique appelée lipolyse. Mes travaux de thèse ont eu pour but d'explorer de nouveaux rôles non enzymatiques de la LHS. Nous montrons ainsi que la LHS se localise au noyau de l'adipocyte, ce qui n'avait encore jamais été rapporté. Dans cet organite, la LHS participe au contrôle du programme transcriptionnel contrôlé par la voie TGFbeta. Dans l'adipocyte, la voie TGFbeta assure un tonus inhibiteur de la biogenèse mitochondriale et du métabolisme oxydatif, en inhibant notamment l'expression de PGC-1alpha, un co-activateur clé de ces phénomènes. A l'inverse, cette voie est aussi responsable d'une régulation positive sur la production de matrice extracellulaire. La voie TGFbeta est ainsi centrale dans le contrôle d'une homéostasie de l'adipocyte entre gènes contrôlant l'activité métabolique mitochondriale et gènes assurant la production de matrice extracellulaire. Nos travaux mettent en lumière la LHS comme pierre angulaire de ce contrôle. D'un point de vue mécanistique, la LHS interagit physiquement avec le facteur de transcription SMAD3, contrôlé par la voie TGFbeta, formant un complexe non canonique et spécifique de l'adipocyte. Le complexe LHS/SMAD3 favorise la transcription des gènes de la matrice extracellulaire. Nous montrons que l'inhibition tonique de l'expression de PGC-1alpha requiert en plus l'association d'un autre partenaire, SFPQ, facteur de transcription et protéine de liaison à l'ARN. La formation et la translocation nucléaire du complexe LHS/SMAD3 sont induites par une stimulation TGFbeta, alors que les phénomènes inverses sont favorisés suite à la phosphorylation de la LHS par la PKA en réponse à un stimulus lipolytique, induisant la translocation de la lipase à la gouttelette lipidique. Les mouvements subcellulaires de la LHS vont ainsi permettre un couplage entre la libération d'acides gras, par sa fonction d'enzyme cytosolique, et le contrôle de leur utilisation, par son rôle nucléaire inhibant le métabolisme oxydatif. Nous mettons en évidence une accumulation de LHS dans le noyau de l'adipocyte au cours de l'obésité chez la souris. Ce phénomène pourrait participer à la pathogenèse de l'obésité et de la résistance à l'action de l'insuline, caractérisées par une augmentation de la signalisation TGFbeta dans le tissu adipeux et des défauts de métabolisme adipocytaire.The work presented in the PhD thesis focuses on the adipocyte, the prototypical cell type of adipose tissue specialized in metabolism. My thesis work was first devoted to the development and use of adipocyte culture models. A published review article details the in vitro models to investigate adipocyte biology. It delineates the pros and cons of ex vivo mature adipocyte cultures and progenitor cell culture models. These models do not fully recapitulate the phenotype of mature adipocytes in an in vivo context. The first objective of my PhD was to develop 3D cultures of murine adipocyte native progenitors in order to achieve higher differentiation than conventional existing 2D cultures. In this spheroid culture, we obtained adipocytes displaying a more mature phenotype, as shown by the formation of unilocular lipid droplets along with increased gene expression of mature adipocyte markers. This work was included in a joint publication with scientists at the Karolinska Institute of Stockholm who developed a similar technique using human progenitors. The main research project during the PhD thesis has been the characterization of a new role of hormone-sensitive lipase (HSL) in the control of adipocyte phenotype and metabolism. This lipase has initially been identified as an enzyme catalyzing the hydrolysis of adipocyte triacylglycerol, a catalytic pathway named lipolysis. I investigated non enzymatic roles of HSL. We revealed the presence of HSL in adipocyte nucleus, a feature never reported. In this organelle, HSL participates to a transcriptional program controlled by the TGFbeta signaling pathway. In adipocytes, TGFbeta signaling was shown to promote tonic inhibition of mitochondrial biogenesis and oxidative metabolism, through repression of the expression of PGC-1alpha, a master transcriptional co-activator. Oppositely, this pathway exerts a positive regulation on extracellular matrix production. The TGFbeta signaling hence plays a central role in the control of adipocyte homeostasis between genes controlling mitochondrial metabolic activity and genes responsible for extracellular matrix deposition. Our work positions HSL as a cornerstone in this control. At the mechanistic level, HSL physically interacts with the TGFbeta-activated transcription factor SMAD3 through constitution of a cell-specific non-canonical complex. The HSL/SMAD3 complex facilitates the transcription of extracellular matrix genes. We show that tonic inhibition of PGC-1alpha expression requires an additional partner, the transcription factor and RNA-binding protein SFPQ. HSL/SMAD3 complex formation and nuclear translocation are induced in response to TGFbeta, whereas the opposite occurs following protein kinase A-mediated phosphorylation of HSL in response to lipolytic stimuli with HSL shuttling from the nucleus to the lipid droplet. The shuttling of HSL between different cellular compartments ensures coupling of fatty acid mobilization, through its cytosolic lipase function, with control of their utilization, through its nuclear role in inhibiting oxidative metabolism. In obese mice, HSL accumulates in adipocyte nuclei. This phenomenon might contribute to the pathogenesis of obesity and insulin resistance, characterized by increased adipose tissue TGFbeta signaling and defective adipocyte metabolism
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