1,721,047 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
Development of Two Organocatalytic Photoredox Transformations: The Enantioselective Cation Radical Diels-Alder Reaction and the Anti-Markovnikov Hydroamination of Alkenes
Full text linkHerein we describe the development of two research projects within the field of organic photoredox catalysis. Both works involve the single electron oxidation of alkenes to generate cation radical intermediates which possess unique reactivity. The cation radical Diels-Alder reaction circumvents traditional electronic restraints on the substrates and allows for cycloaddition to occur between two electron-rich partners. We aimed to render this valuable reaction enantioselective by merging the fields of photoredox catalysis and chiral counteranion catalysis. The precedent for our research proposal and details of our findings are disclosed. We also employed cation radical intermediates for the development of an anti-Markovnikov hydroamination reaction catalyzed by an organic photoredox system. This transformation provides access to important pharmacological agents through the direct addition of amines to alkenes. The products are formed with complete anti-Markovnikov regioselectivity, a feature that is challenging to obtain without precious transition metals. We demonstrate 38 examples of the intra- and intermolecular anti-Markovnikov hydroamination reaction. Notably, the substrate scope includes trisubstituted aliphatic alkenes as well as heteroaromatic amines.Doctor of Philosoph
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
Synthesis of C2 Symmetric Cyclobutanes and gamma-Butyrolactones via Photoinduced Electron Transfer
Full text linkOrganic Photoredox Catalysis An overview of the principles of photoredox catalysis, alkene oxidation, and discussion of organic and inorganic photooxidants, applied in organic chemistry is discussed. [2+2] Cycloaddition Reactions of Alkenes via Single Electron Transfer Catalysis A novel method for the diastereoselective synthesis of lignan cyclobutanes via dimerization of simple olefins is presented. A unique strategy for controlling detrimental cycloreversion and polymerization processes via the use of appropriately tuned electron relays was developed. This method was applied to the direct synthesis of two naturally produced cyclobutane compounds; Magnosalin, and Pellucidin A, as well as a third natural product, Endiandrin A via derivatization. Synthesis of gamma-Butyrolactones via Polar Radical Crossover Cyclization Reactions of Unsaturated Acids And Alkenes The development of a convergent synthesis of biologically relevant gamma-butyrolactone scaffolds by an electron-transfer mediated polar-radical crossover cycloaddition was covered. This transformation proceeded with exquisite regioselectivity, and relied on the implementation of a dual-catalyst system. The utility of this method was showcased via the synthesis of two bioactive natural products within the paraconic acid family.Doctor of Philosoph
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
Anti-Markovnikov Hydrofluorination, Hydrooxysulfonylation and Hydration of Styrenes - Photoredox catalytic Polar-Radical Crossover Cycloaddition of Olefins and Allylic Nucleophiles
Full text linkDescribed herein are two general methodologies for the direct functionalization of Olefins. The direct addition of hydrogen fluoride across a carbon-carbon double bond was enabled by the use of a photoredox catalyst in conjunction with a redox active hydrogen-atom donor. The transformation proceeded via the formation of an alkene radical-cation. This intermediate was shown to interact with fluoride at the least stabilized position and yielded the desired hydrofluorinated product upon hydrogen-atom transfer. The reaction proceeded with complete anti-Markovnikov selectivity. This methodology was expanded to incorporate weak nucleophiles such as strong Brønsted acids and water. In particular, the hydration of olefins was facilitated by the use of a surfactant, which allowed the reaction to be conducted in water. A catalytic Polar-Radical Crossover Cycloaddition (PRCC) reaction is also presented. The PRCC allowed for the synthesis of highly substituted tetrahydrofurans via the addition of allylic alcohols onto alkene radical-cations. The scope of the transformation was investigated and shown to be tolerant of common chemical functionalities. Efforts towards the extension of this methodology to the synthesis of substituted pyrrolidines are also discussed.Doctor of Philosoph
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