1,720,955 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
Development of the tandem oxy-CopeClaisenene reaction: Mechanistic insights and application towards the synthesis of Wiedemannic acid and LL-S491beta
No full textThis thesis explores the tandem oxy-Cope/Claisen/ene reaction and its application towards the total synthesis of two natural products, wiedemannic acid and LL-S491beta. Drawing on earlier studies carried out on the oxy-Cope/ene rearrangement, the oxy-Cope/Claisen/ene reaction adds to the previous methodology by allowing for the formation of highly functionalized decalin cores bearing up to four contiguous stereocentres, including two adjacent quaternary carbons. The scaffolds accessed by this new tandem pericyclic cascade allow for an easy foray into the synthesis of numerous diterpenoid natural products.
The first part of this study focuses on the development of the oxy-Cope/Claisen/ene reaction with respect to both its scope and diastereoselectivity. A combination of experimental methods and theoretical studies allow for the origins of the observed diastereoselectivity to be unveiled. Through the use of judicious substituent selection and/or the addition of remote stereocentres for conformational control, the selectivity of this cascade reaction is effectively controlled.
Armed with a highly efficient and stereoselective method for the preparation of functionalized decalin cores, the second part of this study centres on the application of this method to total synthesis. The preparation of a wiedemannic acid analogue is successfully completed with four of its five adjoining stereocentres being effectively set during the key oxy-Cope/Claisen/ene reaction. Owing to a discrepancy in the reported structure of wiedemannic acid however, the synthesis of the natural product is not further pursued. Rather, a new target is chosen. Several innovative routes towards the synthesis of LL-S491beta are described, each relying on the key tandem reaction cascade to build the core of its pimarane skeleton.
Finally, the last section of this work addresses some of the novel chemistry discovered along the way including a unique ruthenium-mediated lactonization reaction and an enolate isomerization pathway during the oxy-Cope/ene reaction
Development of the tandem oxy-CopeClaisenene reaction: Mechanistic insights and application towards the synthesis of Wiedemannic acid and LL-S491beta
No full textThis thesis explores the tandem oxy-Cope/Claisen/ene reaction and its application towards the total synthesis of two natural products, wiedemannic acid and LL-S491beta. Drawing on earlier studies carried out on the oxy-Cope/ene rearrangement, the oxy-Cope/Claisen/ene reaction adds to the previous methodology by allowing for the formation of highly functionalized decalin cores bearing up to four contiguous stereocentres, including two adjacent quaternary carbons. The scaffolds accessed by this new tandem pericyclic cascade allow for an easy foray into the synthesis of numerous diterpenoid natural products.
The first part of this study focuses on the development of the oxy-Cope/Claisen/ene reaction with respect to both its scope and diastereoselectivity. A combination of experimental methods and theoretical studies allow for the origins of the observed diastereoselectivity to be unveiled. Through the use of judicious substituent selection and/or the addition of remote stereocentres for conformational control, the selectivity of this cascade reaction is effectively controlled.
Armed with a highly efficient and stereoselective method for the preparation of functionalized decalin cores, the second part of this study centres on the application of this method to total synthesis. The preparation of a wiedemannic acid analogue is successfully completed with four of its five adjoining stereocentres being effectively set during the key oxy-Cope/Claisen/ene reaction. Owing to a discrepancy in the reported structure of wiedemannic acid however, the synthesis of the natural product is not further pursued. Rather, a new target is chosen. Several innovative routes towards the synthesis of LL-S491beta are described, each relying on the key tandem reaction cascade to build the core of its pimarane skeleton.
Finally, the last section of this work addresses some of the novel chemistry discovered along the way including a unique ruthenium-mediated lactonization reaction and an enolate isomerization pathway during the oxy-Cope/ene reaction
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
Unlocking the Future: Exploring Generative Artificial Intelligence in Post-Secondary Chemistry Education with a Focus on Summative Assessment Applications
No full textGenerative artificial intelligence (GenAI), specifically ChatGPT, has been gaining traction as a platform that allows users to do several tasks, from planning itineraries to designing logos, to answering questions. Its impacts have been felt across all sectors, including business, healthcare and academia. This systematic review paper focuses on the applications of AI in academia – specifically chemistry education. A comprehensive literature search examined all available articles as of April 2024. A total of 40 articles were found to relate to the theme of GenAI use in chemistry education. These articles were analyzed and mapped by category to provide an overview of GenAI usage and research in this subfield of academia. This resource could be of value to chemistry instructors and teaching assistants interested in exploring GenAI use in their teaching. Following the mapping exercise, the five papers regarding summative assessments were selected for a more in-depth critical review. These papers were evaluated for their approach to incorporating AI into post-secondary chemistry education, and for the author’s attitudes towards GenAI technology. While all author teams found similar shortcomings, such as inaccuracies in the GenAI outputs, how these shortcomings were viewed varied between the papers and shaped the authors’ views towards GenAI. Where some authors saw a problem, others saw an opportunity to leverage imperfect AI outputs to enhance critical thinking skills in their students. Future directions, such as developing more advanced AI models and exploring student engagement, are also discussed in this review
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
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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