1,720,964 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Investigating the Role of MicroRNAs in the Response to Nitrogen Deprivation in the Green Alga Chlamydomonas reinhardtii
No full textMicroalgae are gaining attention as a potential feedstock for the production of biodiesel, mainly derived from triacylglycerols (TAG). In many algae, TAG synthesis increases dramatically upon certain stresses but this is often accompanied by growth retardation. Rational improvements to strain productivity are limited by the scant knowledge on algal lipid metabolism and gene regulatory mechanisms. In this context, systems-level approaches aimed at understanding and modeling metabolic and regulatory networks may enable hypothesis-driven genetic engineering strategies. The green microalga Chlamydomonas reinhardtii accumulates significant amounts of TAGs under nutrient starvation and provides a genetically tractable model for manipulating biosynthetic pathways. In order to gain insight into Chlamydomonas TAG metabolism and regulation, we have examined both the transcriptome of strain CC-125 grown photoautotrophically in nutrient-replete or nitrogen-depleted media and the corresponding changes in microRNA population. While the production of microRNAs (miRNAs) by Chlamydomonas reinhardtii has been established for several years, little is known about how they target transcripts for regulation or what roles they play in cellular processes, in particular whether they play a role in regulating the accumulation of TAG in nitrogen-depleted media. To characterize functional miRNAs in Chlamydomonas, we identified small RNAs associated with Flag-tagged-AGO3 by affinity purification and deep sequencing in cells grown heterotrophically and cells grown photoautotrophically in nitrogen-replete and nitrogen-deplete media and used these small RNAs to determine changes in the miRNA populations across these three conditions. We determined the role that these miRNAs play in regulating the response to nitrogen-deplete media by searching the genes that are differentially expressed in that condition for potential targets of these miRNA
Variations on the Author
No full text“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
No full textWe 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
Consensus Ensemble Approaches Improve De Novo Transcriptome Assemblies
No full textAccurate and comprehensive transcriptome assemblies lay the foundation for a range of analyses, such as differential gene expression analysis, metabolic pathway reconstruction, novel gene discovery, or metabolic flux analysis. With the arrival of next-generation sequencing technologies it has become possible to acquire the whole transcriptome data rapidly even from non-model organisms. However, the problem of accurately assembling the transcriptome for any given sample remains extremely challenging, especially in species with a high prevalence of recent gene or genome duplications, those with alternative splicing of transcripts, or those whose genomes are not well studied. This thesis provides a detailed overview of the strategies used for transcriptome assembly, including a review of the different statistics available for measuring the quality of transcriptome assemblies with the emphasis on the types of errors each statistic does and does not detect and simulation protocols to computationally generate RNAseq data that present biologically realistic problems such as gene expression bias and alternative splicing. Using such simulated RNAseq data, a comparison of the accuracy, strengths, and weaknesses of seven representative assemblers including de novo, genome-guided methods shows that all of the assemblers individually struggle to accurately reconstruct the expressed transcriptome, especially for alternative splice forms. Using a consensus of several de novo assemblers can overcome many of the weaknesses of individual assemblers, generating an ensemble assembly with higher accuracy than any individual assembler.
Advisor: Jitender S. Deogu
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Investigating the Role of MicroRNAs in the Response to Nitrogen Deprivation in the Green Alga \u3ci\u3eChlamydomonas reinhardtii\u3c/i\u3e
No full textMicroalgae are gaining attention as a potential feedstock for the production of biodiesel, mainly derived from triacylglycerols (TAG). In many algae, TAG synthesis increases dramatically upon certain stresses but this is often accompanied by growth retardation. Rational improvements to strain productivity are limited by the scant knowledge on algal lipid metabolism and gene regulatory mechanisms. In this context, systems-level approaches aimed at understanding and modeling metabolic and regulatory networks may enable hypothesis-driven genetic engineering strategies. The green microalga Chlamydomonas reinhardtii accumulates significant amounts of TAGs under nutrient starvation and provides a genetically tractable model for manipulating biosynthetic pathways. In order to gain insight into Chlamydomonas TAG metabolism and regulation, we have examined both the transcriptome of strain CC-125 grown photoautotrophically in nutrient-replete or nitrogen-depleted media and the corresponding changes in microRNA population. While the production of microRNAs (miRNAs) by Chlamydomonas reinhardtii has been established for several years, little is known about how they target transcripts for regulation or what roles they play in cellular processes, in particular whether they play a role in regulating the accumulation of TAG in nitrogen-depleted media. To characterize functional miRNAs in Chlamydomonas, we identified small RNAs associated with Flag-tagged-AGO3 by affinity purification and deep sequencing in cells grown heterotrophically and cells grown photoautotrophically in nitrogen-replete and nitrogen-deplete media and used these small RNAs to determine changes in the miRNA populations across these three conditions. We determined the role that these miRNAs play in regulating the response to nitrogen-deplete media by searching the genes that are differentially expressed in that condition for potential targets of these miRNA.
Adviser: Heriberto Cerutt
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