1,721,008 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
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
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
Identification of key actors involved in bone tissue development and osteosarcoma progression through studies of active super-enhancers
No full textLes super-enhancers (SE) correspondent à des groupement d'enhancers qui recrutent le complexe transcriptionnel pour induire la transcription de leurs gènes cibles plus efficacement que les enhancers. Ils régulent des gènes clés définissant l'identité cellulaire dans des conditions physiologiques et pathologiques. Les objectifs de ce projet de thèse étaient de caractériser le développement osseux normal par l'étude des gènes clés de l'ostéoblastogenèse et de l'ostéoclastogenèse et de caractériser l'évolution métastatique de l'ostéosarcome (OS), la tumeur osseuse primitive maligne la plus fréquente. Nous avons traqué la reprogrammation épigénétique qui se produit au cours de l'ostéoclastogenèse, et associé les SEs actifs dynamiques à leurs gènes cibles potentiels. Ainsi, nous avons pu observer un profil dynamique d'enhancers actifs qui stimule la transcription de gènes clés définissant l'identité des ostéoclastes. L'expression de ces gènes semble être particulièrement affectée par l'exposition au diuron, pesticide suspecté de provoquer des troubles du développement squelettique, altérant la maturation des ostéoclastes. Afin d'identifier les facteurs de transcription (TFs) impliqués dans l'ostéoblastogenèse, nous avons traqué les gènes codant pour des TFs induits par des SEs actifs spécifiques de l'état de différenciation dans un modèle in vitro de différenciation ostéoblastique de cellules souches mésenchymateuses (CSMs). Un ChIP-Sequencing contre la marque H3K27ac des enhancers actifs a été réalisé sur des cellules traitées et non traitées avec du milieu de différenciation à différents temps, ainsi qu'un RNA-Sequencing aux mêmes temps. Nous avons identifié 3 TFs, clés pour l'ostéoblastogenèse, comme cibles de SEs actifs spécifiques du stade de différenciation tardif et un TF induit par un SE spécifique aux CSMs. Les modifications de l'expression de ces TFs liées aux SEs peuvent être des stratégies prometteuses pour lutter contre divers troubles du tissu osseux. En parallèle, nous avons comparé les profils des SEs actifs dans différentes lignées cellulaires d’OS et dans des échantillons tumoraux extraits de sites primaires et métastatiques. Le regroupement hiérarchique des profils de SEs actifs nous a permis de distinguer deux ensembles d'échantillons d’OS : un groupe contenant les échantillons primaires et la lignée cellulaire MG63 et un second groupe contenant les échantillons métastatiques et les lignées cellulaires U2OS et HOS-MNNG. Nous avons identifié 3 gènes qui sont induits par des SEs actifs spécifiques aux métastases. Les sous expressions simultanées des 3 gènes identifiés diminuent les capacités d'infiltration et de motilité des HOS-MNNG et donc leur capacité métastatique. Le suivi des gènes cibles des profils évolutifs des SEs actifs pourrait par conséquent être utilisé pour l'identification des gènes qui gouvernent la différenciation cellulaire et façonnent le comportement cellulaire, qu'il soit physiologique ou pathologique.Super-enhancers (SEs) are cluster of enhancers that recruit the transcriptional complex to induce the transcription of their target genes more efficiently than enhancers. They regulate key cell identity defining genes in physiological and pathological conditions. The objectives of this thesis project were to characterize normal bone development through the study of osteoblastogenesis and osteoclastogenesis driver genes and to characterize the metastatic evolution of osteosarcoma (OS), the most frequent malignant primary bone tumour. We tracked the epigenetic reprogramming occurring during osteoclastogenesis, and associated dynamic active SEs to their potential target genes. As such, we were able to observe a dynamic active enhancers profile that boosts transcription of key osteoclasts identity defining genes. The expression of these genes seemed to be particularly affected by diuron exposure, pesticide suspected to cause skeletal disorders, impairing osteoclasts maturation. In order to identify transcription factors (TFs) involved in osteoblastogenesis, we tracked TF-encoding genes induced by differentiation state specific active SEs in an in vitro model of mesenchymal stem cells (MSCs) osteoblastic differentiation. ChIP-Sequencing for the active enhancers marker H3K27ac was performed in differentiation medium treated and untreated cells at different time points along with RNA-Sequencing at the same time points. We identified 3 TFs, key for osteoblastogenesis, as targets of late stage differentiation specific active SEs and one MSCs specific SE induced TF. Expression modifications of these SEs related TFs may be promising strategies to fight against various bone disorders. In parallel, we compared the active SEs profiles in different OS cell lines and tumor samples extracted from primary and metastatic sites. Hierarchical clustering on the active SEs profiles allowed us to distinguish two sets of OS samples: one group containing the primary samples and MG63 cell line and the other containing metastatic samples with U2OS et HOS-MNNG cell lines. We identified 3 genes that are induced by metastasis specific active SEs. Simultaneous down expressions of the 3 identified genes decrease HOS-MNNG infiltration and motility capacities and thus their metastatic capacity. Tracking target genes of the evolving active SEs profiles could as a result be used for the identification of genes that drive cell differentiation and shape cellular behavior, whether physiological or pathological
Multi-sample analysis of dynamic super-enhancers to better characterize normal bone development and osteosarcoma evolution
No full textLes super-enhancers (SEs) sont des clusters d’enhancers qui recrutent une concentration particulièrement élevée de resources transcriptionnelles. Les SEs ont été signalés comme responsables de la mise en place et du maintien des programmes transcriptionnels qui définissent l’identité des cellules. Les objectifs de ce projet de thèse étaient de mieux caractériser le développement osseux normal, l’évolution métastatique des ostéosarcomes et l’émergence de la chimiorésistance dans les ostéosarcomes. Notre stratégie était d’identifier les cibles des SE afin de révéler les gènes définissant l’identité des cellules osseuses dans les contextes physiologique et pathologique. Afin d’associer plus précisément les SE à leurs gènes cibles, nous avons effectué une analyse combinée des signaux H3K27ac des SE et des niveaux d’expression des gènes environnants. L’analyse de SEs dynamiques et de leurs potentiels gènes cibles lors des différenciations ostéoclastique et ostéoblastique nous a révélé des gènes qui semblent être clés dans le développement osseux. L’étude des profils de SEs dans des échantillons d’ostéosarcome nous a également révélé des gènes potentiellement clé dans l’évolution de l’ostéosarcome. Les études présentées dans ce projet de thèse soutiennent l’importance de cartographier les SEs, cela pouvant ainsi permettre l’identification de gènes définissant l’identité cellulaireSuper-enhancers (SEs) are clusters of enhancers able to recruit exceptional concentrations of transcriptional resources. Interestingly, SEs were reported in several studies as responsible for the setup and maintenance of transcriptional programs that define cell identity. The objectives of this thesis project were to better characterize normal bone development, find causes or markers of osteosarcoma’s metastatic evolution and the emergence of chemo-resistance in osteosarcoma. Our strategy was to identify targets of SE in order to reveal genes defining bone cells’ identity in physiological and pathological contexts. To more precisely associate SEs to their target genes, we performed ChIP-Sequencing against H3K27ac and RNA-Sequencing in multiple samples and performed correlation tests between dynamic SEs and genes located within the Topologically Associated Domains (TADs) of these SEs. Studies of dynamic SEs and their potential target genes in the course of osteoblastic and osteoclastic differentiation have revealed potential key actors in bone development. A comparison of the epigenetic profiles of different osteosarcoma samples has unveiled important epigenetic and transcriptional modifications that seem to drive osteosarcoma evolution. The studies presented in this manuscript support that mapping SEs can reveal cell identity-defining genes
- …
