1,720,957 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
Non-coding RNA Expression, Function, and Variation during Drosophila Embryogenesis
Get PDFLong non-coding RNAs (lncRNAs) can often function in the regulation of gene expression during development; however, their generality as essential regulators in developmental processes and organismal phenotypes remains unclear. Here, we performed a tailored investigation of lncRNA expression and function during Drosophila embryogenesis, interrogating multiple stages, tissue specificity, nuclear localization, and genetic backgrounds. Our results almost double the number of annotated lncRNAs expressed at these embryonic stages. lncRNA levels are generally positively correlated with those of their neighboring genes, with little evidence of transcriptional interference. Using fluorescent in situ hybridization, we report the spatiotemporal expression of 15 new lncRNAs, revealing very dynamic tissue-specific patterns. Despite this, deletion of selected lncRNA genes had no obvious developmental defects or effects on viability under standard and stressed conditions. However, two lncRNA deletions resulted in modest expression changes of a small number of genes, suggesting that they fine-tune expression of non-essential genes. Several lncRNAs have strain-specific expression, indicating that they are not fixed within the population. This intra-species variation across genetic backgrounds may thereby be a useful tool to distinguish rapidly evolving lncRNAs with as yet non-essential roles.Fil: Schor, Ignacio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. European Molecular Biology Laboratory; AlemaniaFil: Bussotti, Giovanni. European Bioinformatics Institute; Reino UnidoFil: Maleš, Matilda. European Molecular Biology Laboratory; AlemaniaFil: Forneris, Mattia. European Molecular Biology Laboratory; AlemaniaFil: Viales, Rebecca R.. European Molecular Biology Laboratory; AlemaniaFil: Enright, Anton J.. European Bioinformatics Institute; Reino UnidoFil: Furlong, Eileen E. M.. European Molecular Biology Laboratory; Alemani
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
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
Natural sequence variation as a tool to dissect gene expression regulation in Drosophila melanogaster
Get PDFGenetic variation is a major cause of differences between individuals and it represents a powerful tool to study gene regulation. By interfering with cis- Regulatory Modules (CRMs), variants can unravel CRM function. On the other hand, predicting the effect of variants on phenotype by the DNA sequence has proven to be challenging. In this thesis, I use Drosophila embryonic development as a model system to study diversity in gene regulation at the transcriptional level.
CRMs can be characterized using multiple genome-wide techniques such as DNase hypersensitivity. However, despite having comprehensive CRM maps, it is still difficult to predict what are the genes regulated by each CRM. Functional methods, such as mutagenesis, are effective but poorly scalable. To address this issue, I developed an eQTL method (called DHS-eQTL) that makes use of naturally occurring genetic variation, to associate CRMs with the genes they regulate. The results reveal 2,967 DHS-eQTLs and indicate a high extent of CRM sharing between genes. We validated the results with in silico and in vitro approaches and I discuss upcoming in vivo experiments. We observed long-range enhancer regulation suggesting that commonly used methods to associate genes and enhancers underestimate their distance. Also, the DHS-eQTLs show that promoter-proximal CRMs have widespread distal activity.
The separation between populations causes an increase in genetic differences by drift and adaptation to different environments. We investigated gene expression differences between Drosophila populations from five continents by performing RNA-Seq on 80 inbred fly lines. We performed multiple quality-control tests to ensure that the gene expression dataset is of high quality. Gene expression profiles show detectable diversity among the fly lines from different continents and confirm what has been observed at the genetic level. In particular, the African population is the most separated, while the American, European and Australian ones show less diversity. In addition, we identified 903 gene and 2,021 exon eQTLs.
Genetic variants can interfere with Transcription Factor Binding Sites (TFBS) and this might, in turn, lead to changes in chromatin accessibility. We applied LS-GKM (an SVM method that uses gapped k-mers) to learn sequence features of tissue-specific accessible chromatin and predict the impact of natural sequence variation on accessibility. We train LS-GKM on six tissue-specific training sets: neuroectodermal, mesodermal and double negative CRMs divided in promoter-proximal and promoter-distal. The method unbiasedly recovers tissue-specific TFBS and shows good performance despite the small training sets. Finally, we score variants from groups of inbred Drosophila lines. Interestingly, rare variants have a higher impact on accessibility
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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