1,721,303 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
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
Molecular and functional characterization of a testis-specific TRS4 gene in spermatogenesis
No full textpublished_or_final_versionObstetrics and GynaecologyMasterMaster of Philosoph
An investigation into the biochemical and biological properties of zona-binding inhibitory factor 1 from human follicular fluid
No full textpublished_or_final_versionObstetrics and GynaecologyDoctoralDoctor of Philosoph
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
Identification and characterization of human oviductal cell derived embryotrophic factor 3
No full textpublished_or_final_versionabstracttocObstetrics and GynaecologyDoctoralDoctor of Philosoph
Effects of TCDD on embryonic stem cells's (ESCS) differentiation towards pancreatic lineage and pancreatic beta cell function
No full text2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an endocrine disrupting chemical postulated to exert diabetogenic effects. Most laboratory and epidemiological studies have demonstrated the association of persistent TCDD exposure to type 2 diabetes (T2D) susceptibility. Researchers commonly employ super high doses of TCDD treatments on adult cells/tissues to illustrate its diabetogenic effects which does not reflect physiological phenotypes. Data linking the epigenetic effects of TCDD exposure on embryonic cells / tissue to T2D susceptibility risks is very limited. It is therefore hypothesized that TCDD exposure during embryogenesis could influence development and epigenetic landscape of pancreatic islets, leading to T2D susceptibility later in life. The main objectives of this research were (i) to differentiate embryonic stem cells (ESCs) towards pancreatic lineage cells, (ii) to study the effects of TCDD treatment on human and mouse ESCs (hESCs and mESCs), (iii) to study the effects of TCDD on global DNA methylation pattern of ESCs and (iv) to conduct functional study on some TCDD induced differentially methylated target genes in functional beta cells.
DMSO and physiological doses of TCDD (10pM, 100pM) treated hESCs and mESCs were differentiated towards pancreatic lineage. The results showed that TCDD treatment impaired the ESCs to pancreatic lineage differentiation potentials by suppressing some marker gene expressions in the derived definitive endoderm (DE) and pancreatic progenitors (PP) stages. The extracted DNA of the DMSO and TCDD treated hESCs were subjected to reduced representation bisulfite sequencing (RRBS) to generate methylome data and the results showed that TCDD treatments induced differential DNA methylation in the hESCs state. Bioinformatic analysis using Database for Annotation, Visualization and Integrated Discovery (DAVID) and Gene Set Enrichment Analysis (GSEA) of the methylome data revealed that biological pathways and processes related to pancreatic lineage cell development and functions (e.g. endoderm cell differentiation, insulin secretions, insulin signaling pathway) were enriched in the physiological doses of TCDD induced hypermethylated genes, while different pathways were induced by supraphysiological dose of TCDD. Among the pancreatic lineage enriched genes, PRKAG1, CAPN10, MAFA and HNF-1B were validated by bisulfite sequencing. The results showed that some TCDD induced hypomethylated genes were also reported to be hypomethylated in the islets of T2D patients.
PRKAG1, one of the gamma regulatory subunits of AMP-activated protein kinase (AMPK) that was related to insulin resistance and metabolic syndrome-related diseases, was selected for downstream study. It was found that TCDD induced PRKAG1 hypermethylation at the hESCs state was maintained after differentiated into PP stage. In the functional studies, Prkag1 knockdown in INS-1E cells increased GSIS but decreased AMPKα and AMPKβ2 protein amounts. Prkag1 knockdown also induced the protein levels of mTORC1 and its downstream target, 4EBP1 in the transfected cells.
In conclusion, this research is the first to demonstrate that the TCDD induced hypermethylation of the PRKAG1 was maintained during differentiation of hESCs to PP. TCDD induced Prkag1 hypermethylation might lead to hyperactivation of mTOR1 pathway and increase in GSIS. The current research data established that TCDD might exert diabetogenic effects during early prenatal development, alter processes of pancreatogenesis and increase the risk of T2D susceptibility later in life.published_or_final_versionObstetrics and GynaecologyDoctoralDoctor of Philosoph
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