1,720,989 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
Zelluläre, biochemische und phylogenomische Analysen des murinen Jumonji domain containing 6 Proteins erbringen neue Hinweise für eine Funktion als 2-Oxoglutarat abhängige Dioxygenase
Full text linkThe “jumonji domain containing 6” protein (Jmjd6) is involved in embryogenetic tissue differentiation and cytokine release of activated macrophages. Given the importance of jumonji C (JmjC) domain-containing proteins in oxidative DNA and RNA repair, protein hydroxylation, and histone lysine demethylation, an analysis of the Jmjd6 locus, evolution, and protein function was carried out. Sequences homologous to the mouse Jmjd6 protein were identified in 61 species from all major living phyla. This lead to the identification and characterisation of a bi-directional transcriptional unit comprising Jmjd6 and the neighbouring 1110005A03Rik locus, verification of a novel Jmjd6 exon and two new splice variants in vivo. A calculated and cross-validated structural model of the Jmjd6 protein identified a conserved double stranded ß-helix (DSBH) fold, an 2-His-1-carboxylate facial triad, and a 2-oxoglutarate co-ordination site as structural motifs. Using mAB328, a newly generated monoclonal anti-Jmjd6 antibody, it was shown that endogenous Jmjd6 is a nuclear and nucleolar, cell cycle dependent protein with no co-localisation to heterochromatic DNA. Western blot analyses showed that Jmjd6 forms homo-multimers, that homo-multimerization requires the full-length protein and identified an N-terminal protein multimerization domain. An analysis of H3K4, H3K9, H3K27, H3K36, and H4K20 histone methylation states in wildtype and Jmjd6 -/- cells and overexpression of Jmjd6-reporter constructs excluded a function of Jmjd6 in the demethylation of these residues. Finally, nuclease assays showed a likely association of Jmjd6 to a ribonucleic matrix. In conclusion, additional evidence that Jmjd6 functions most likely as a nonheme-Fe(II)-2-oxoglutarate-dependent dioxygenase and novel insights into the evolution of Jmjd6 and JmjC domain-containing proteins are provided. The results suggest that enzymatic targets of Jmjd6 might be RNA or RNA-associated proteins and not histone lysine residues.Das “jumonji domain containing 6”-Protein (Jmjd6) ist an der embryonalen Gewebedifferenzierung und der Zytokinausschüttung aktivierter Makrophagen beteiligt. Wegen der Bedeutung von jumonji C (JmjC) Domäne-Proteinen bei der oxidativen DNA und RNA Reparatur, der Protein Hydroxylierung und der Histon Lysin-Demethylierung wurde der Lokus, die Evolution und die Proteinfunktion von Jmjd6 analysiert. In Spezies aller heutigen Phyla wurden 61 Maus-Jmjd6-homologe Sequenzen identifiziert. Dies führte zu der Identifizierung und Charakterisierung einer bidirektionalen Transkriptionseinheit aus Jmjd6 und dem benachbarten 1110005A03Rik Lokus, eines neuen Jmjd6 Exons sowie zweier neuer Splice-Varianten in vivo. Ein berechnetes und kreuz-validiertes Strukturmodell von Jmjd6 identifiziert eine doppelsträndige ß-Helix (DSBH)-Faltung, eine 2-His-1-Carboxylat-Triade und eine 2-Oxoglutarat-Koordinierungsstelle als wahrscheinliche Strukturmotive. Durch mAB328, einem neu generierten anti-Jmjd6 Antikörper, konnte gezeigt werden, dass endogenes Jmjd6 ein nukleäres und nukleoläres, zellzyklusabhängiges Protein ist, dass keine Kolokalisation mit heterochromatischer DNA zeigt. Western Blot-Analysen zeigten zudem, dass vollständige Jmjd6-Proteine Multimere formen und sich N-terminal eine Multimersierungsdomäne befindet. Eine Funktion als Demethylase von H3K4, H3K9, H3K27, H3K36 und H4K20 Histon Methylierungsstatien konnte durch den Vergleich von Wildtyp und Jmjd6 -/- Zellen sowie durch Überexpression von Jmjd6-Reporterkonstrukten ausgeschlossen werden. Nuklease-basierte Tests zeigten zudem, dass Jmjd6 wahrscheinlich mit einer ribonuleären Matrix assoziiert. Zusammengefasst wurden zusätzliche Beweise für eine Funktion als nonheme-Fe(II)-2-Oxoglutarat-abhängige Dioxygenase und neue Einblicke in die Evolution von Jmjd6 und JmjC-Domänen erbracht. Die Ergebnisse legen nahe, dass die enzymatische Funktion von Jmjd6 gegen RNA oder RNA-assoziierte Proteine und nicht gegen Histon Lysin-Reste gerichtet ist
Analysis of gene regulation on basis of comparative transcriptome-proteome analyses and promoter studies in mice
Full text linkIm Rahmen dieser Arbeit konnte aufgezeigt werden, dass mit Hilfe der RNA-Expressionsanalyse mittels DNA-Chiptechnologie im Mausmodell sowohl eine ausreichend umfangreiche, als auch prinzipiell erfolgreiche Studie der Genexpression in unterschiedlichen biologischen Fragestellungen möglich ist. Bisher ist wenig über die Verbindung von transkriptioneller und post-transkriptioneller Regulation der Genexpression bekannt. Im Speziellen sind Ergebnisse von umfassenden vergleichenden Transkriptom- und Proteom-Analysen in diesem Modellorganismus sehr beschränkt. Um die generelle Durchführbarkeit einer solchen vergleichenden Genexpressionsanalyse zu testen, wurde innerhalb dieser Arbeit auf DNA-Chip-basierendes RNA-Expressionsprofiling und 2D-Gelelektrophorese in Kombination mit Massenspektroskopie von Proteinen aus Leber- und Nierenextrakten der Maus verwendet. Obwohl die Proteinanalysen meistens bekannte metabolische Enzyme und Strukturproteine in diesen Geweben identifizierten, zeigten die Transkriptom-Analysen die differentielle Expression von funktionell verschiedenen Genen auf, sowie zusätzlich eine signifikante Anzahl von Genen, welche funktionell noch nicht beschrieben sind. Die vergleichende Analyse der am stärksten differentiell exprimierten Proteine und deren korrespondierender Transkripte, deutete auf eine Korrelation zwischen transkriptioneller und translationeller Expression für die Mehrzahl der Gene hin. Bedeutende Ausnahmen von dieser Korrelation bestätigten die Komplementarität beider Untersuchungsansätze. Basierend auf den RNA-Expressionsdaten der 200 am stärksten zwischen Leber und Niere differentiell exprimierten Gene, wurde die chromosomale Co-Lokalisation von bekannten und bislang noch nicht beschriebenen Genclustern identifiziert. Diese Untersuchung ergab, dass die räumliche Organisation und evolutionäre Konservierung von solchen Genclustern möglicherweise auf gemeinsame genregulatorische Funktionen schließen lässt. Ergänzend zu den Untersuchungen zur genomweiten Genregulation sind im Rahmen dieser Arbeit Promotorstudien eines einzelnen Gens (Dll1) angefertigt worden.In the context of this work, it has been shown that with the help of RNA-expression analysis by means of DNA-chip technology in the mouse model, both a sufficiently extensive and in principal successful study of gene expression in different biological questions is possible. Furthermore, not much is known about the connection of transcriptional and post-transcriptional gene regulation. Data from comparative transcriptome and proteome analyses in this model organism are very limited. Within this work, DNA chip-based RNA expression profiling and 2D gel electrophoresis, combined with peptide mass fingerprinting of liver and kidney, has been used to explore the general feasibility of such comprehensive gene expression analyses. Although protein analyses mostly identify known metabolic enzymes and structural proteins, transcriptome analyses reveal the differential expression of functionally diverse and not yet described genes. The comparative analysis suggests correlation between transcriptional and translational expression for the majority of genes. Significant exceptions from this correlation confirm the complementarities of both approaches. Based on RNA expression data from the 200 most differentially expressed genes, chromosomal co-localization of known, as well as not yet described, gene clusters has been identified. This highlights the possibility, that spatial organization and evolutionary preservation of such gene clusters may suggest common gene regulatory functions. Supplementary, promoter studies of Dll1 were implemented in the context of the described work on gene regulation
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
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