1,721,064 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
Control of gene expression by cell size
Full text linkThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references.Polyploidy, increased copy number of whole chromosome sets in the genome, is a common cellular state in evolution, development and disease. Polyploidy enlarges cell size and alters gene expression, producing novel phenotypes and functions. Although many polyploid cell types have been discovered, it is not clear how polyploidy changes physiology. Specifically, whether the enlarged cell size of polyploids causes differential gene regulation has not been investigated. In this thesis, I present the evidence for a size-sensing mechanism that alters gene expression in yeast. My results indicate a causal relationship between cell size and gene expression. Ploidy-associated changes in the transcriptome therefore reflect transcriptional adjustment to a larger cell size. The causal and regulatory connection between cell size and transcription suggests that the physical features of a cell (such as size and shape) are a systematic factor in gene regulation. In addition, cell size homeostasis may have a critical function - maintenance of transcriptional homeostasis.by Chia-Yung Wu.Ph.D
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
Mechanisms underlying cell-to-cell diversity in clonal populations of yeast
Full text linkThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references.The FLO promoters are among the largest promoters in yeast and receive a complex combination of signals from upstream signaling pathways through their association with downstream DNA binding factors and chromatin remodelers. The genes regulated by these promoters encode cell-surface glycoproteins that mediate a range of cell-to-cell and cell-to-surface adhesions. Phenotypic diversity in clonal populations of yeast cells is mediated in part by epigenetic silencing of the FLO10 and FLO11 promoters. Silencing of the FLO promoters is heterogeneous, or variegated, within a clonal population of cells. The variegated transcription of FLO10 and FLO11 results in a population of yeast cells that exhibits cell-to-cell variability in flocculation, adhesion to and invasion of inert surfaces, and filamentous growth. In this thesis, I discuss chromatin modifying proteins that localize to the FLO10 and FLO11 promoters and act in trans to affect transcription and silencing at these promoters. I describe the results of genome-wide screens to identify additional trans-acting chromatin modifying factors that play roles in the transcriptional regulation and silencing of the FLO10 and FLO11 promoters. Some of the candidates identified in these screens had effects on FLO transcription that initially seemed paradoxical in light of contemporary theories regarding the role of chromatin structure in regulating transcription. Given that histone deacetylases generally repress transcriptional activity, we were particularly surprised to find that mutations in components of the Rpd3L histone deacetylase complex reduce FLO promoter activity, indicating that Rpd3L plays a role in transcriptional activation of FLO genes. Careful analysis of these mutants, their phenotypes, the transcription of FLO11, and most importantly, the noncoding transcripts that we have detected in the promoter region of FLO11, have revealed the basis for this apparent paradox.by Stacie L. Bumgarner.Ph.D
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
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