1,720,989 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
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
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
Microwave-assisted flow processing in heterogeneously copper nano-catalyzed reactions
Get PDFIn the last decades, micro-processing and microwave technology have been established as mature technologies, however, mainly instigated by academia. Many advances in micro-process technology have led to novel routes and/or process windows to replace batch operations by more efficient continuous processes, both at lab and at industrial scales. Especially, the fine-chemicals industry has been recognized for realistic implementation of these technologies with respect to both scale as well as cost. In this thesis, the major hurdles to combine microwave and micro-processing technology for organic syntheses have been addressed. In comparison to gas-phase reactions, metal-catalyzed liquid-phase organic synthesis requires different operational process windows to realize successful implementation of micro-processing. Major issue here is to avoid solid bases and slurry catalysts by including pre-treatment steps and depositing catalysts onto structured supports. In addition, the use of metals as catalysts under microwave irradiation is known for rapid energy absorption and, therefore, requires special attention regarding temperature control. The Ullmann-type coupling reaction and the Simmons-Smith type cyclopropanation are both intensively employed in the fine-chemicals industry and were, therefore, investigated over various novel heterogeneous Cu catalysts in this project. The Cu-catalyzed coupling of aromatic compounds is not only an excellent example to investigate the benefits of integrated microwave and micro/milli-reactor technologies, but also for its potential applications in the production of pharmaceutically active molecules, such as antivirals and antibiotics (e.g. Vancomycin). This type of organic reactions provides considerable challenges to overcome, both with respect to the severe reaction conditions and, undoubtedly, the sustainability of heterogeneous catalysis which substantially contributes to the cost in flow processing. More importantly, however, was the use of heterogeneous CuZn nano-colloids which, as oxidative stable "metallic microwave-absorber", provide an additional benefit (but also point of attention) regarding the higher temperatures at the locus of the reaction. Therefore, monometallic and bimetallic Cu-based nanoparticles with a narrow size-distribution and a high resistance against oxidation and agglomeration were developed. The chemical and colloidal stability of these Cu-based nanoparticles, including their purity and morphology, could be significantly improved by coating the copper nanoparticles with poly(N-vinylpyrrolidone). These nano-catalysts were then tested for their performance in the Ullmann-type coupling reaction and the Simmons-Smith cyclopropanation. Subsequently, these novel nano-catalysts were immobilized onto a microwave-transparent TiO2 support and used in a fixed-bed reactor. Novel routes for the preparation of highly active TiO2-supported Cu and CuZn catalysts were proposed and applied in Cu-catalyzed organic reactions. The copper oxidation was significantly suppressed by using CuZn/TiO2 catalytic films and a strong relation between the catalyst composition and activity was found for the Ullmann C O coupling reaction. This novel preparation method was based on titania dip-coating onto glass beads, obtaining either structured mesoporous or non-porous titania thin films, which could be loaded with the catalyst nanoparticles by deposition onto the calcined films. These catalysts were analyzed using various characterization techniques and in operando synchrotron X-ray absorption spectroscopy, giving a better understanding of their catalytic behavior. Besides catalyzing a reaction, the energy supply towards the catalyst surface is obviously as important and has been also investigated in this project. This issue has been addressed separately, because in traditional reactors the energy supply is particularly governed by classical heat transfer limitations. Furthermore, the troubleshooting of the major obstacles for continuous operations to synergize the benefits of microwave systems and micro/milli-processing in flow synthesis has been targeted. A micro fixed-bed reactor was designed, using packed spherical glass beads coated with the catalyst and support, for kg-scale flow operations in the Ullmann C-O coupling. In addition, the influence of reactor shape and dimensions for effective microwave irradiation was studied. Experimental evidence of complete microwave penetration in the radial direction was found, allowing rapid and controlled heating without significant radial temperature gradients in the flow-through reactors. The above mentioned developments in chemistry, nano-catalysis and reactor engineering were the basis for an extended cost study, consisting of 14 process scenarios. In this way, the cost-impact of micro-processing and microwave heating for liquid-phase reactions in fine-chemicals synthesis could be envisaged. Two examples were studied, i.e. the Ullmann-type coupling reactions and the Aspirin synthesis. It could be concluded that the operating costs in the Ullmann-type processes compared to those of the Aspirin synthesis can be defined as either material based (e.g. reactant excess, pretreatment and catalyst synthesis) or downstream processing based (e.g. work-up, waste treatment) processes. The impact of integrating microwave heating and micro-processing systems on profitability was evaluated with respect to operational costs and chemical productivity. This techno-economic evaluation provided a route map, highlighting feasible routes to combine different technologies, chemical processes and catalyst systems
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