1,720,970 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
An Organocatalytic Approach to the Synthesis of Six-Membered Heterocycles
No full textIn the last few years, the new era of organocatalysis opened up an effective and efficient way to high yielding metal free, enantio- and diastereoselective reactions leading to six-membered heterocycles. This review provides an overview of the current achievements in the organocatalytic synthesis of these crucial building blocks. Ranging from hetero-Diels-Alder to cycloadditions, from one step cyclizations to cascade reactions, recent results offer new powerful tools to obtain six membered heterocycles with facile procedures in high yields and stereoselection, often leading to many new stereogenic centres in a single reaction. The total syntheses of natural products having heterocyclic ring formation as crucial stage, are also reported. When available, alternative supported organocatalysts have been examined
Stereochemistry in Reaction of Chiral Cyclic Allylsilanes with (Ethoxycarbonyl)nitrene. A New Route to Chiral N-Substituted Allylamines
No full textDispelling 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
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
Selective Oxidation of Benzyl Alcohol catalyzed by CeO2-Nanorods Supported Palladium”.
No full textSelective oxidation of benzyl alcohol (BA) to benzaldehyde (BZ) is considered as a crucial functional group transformation, since the product is a key intermediate for the synthesis of fine chemicals, in the perfume, pharmaceutical and dyestuff industries. This oxidation reaction is conventionally performed by various stoichiometric oxygen donors such as chromates, permanganates, and peroxides which are expensive and highly toxic. Therefore, from environmental point of view, and to reduce the overall production cost, there is a great interest in the development of heterogeneous catalysts capable of utilizing air or O2 as greener oxidants.
Supported noble-metal catalysts has been investigated in numerous studies and showed promising potential to carry out selective oxidation of BA to BZ; however, various issues such as catalyst deactivation and BZ selectivity must be overcome for the industrial implementation of this reaction.
In this research work, the selective oxidation of BA to BZ was studied using Palladium supported on CeO2 Nanorods (NR) as catalyst, and atmospheric air as greener oxidant.
CeO2-NR were prepared according to previously published hydrothermal method [10]. Palladium oxide was deposited by wet-impregnation on CeO2-NR using Pd(NO3)2 • 2H2O and calcination at 400 °C (PdO/CeO2-NR). The effect of oxidation state of palladium on the catalytic activity was also investigated by using the reduced form of the catalyst (Pd/CeO2-NR-H2). Structural, morphological and redox properties of the synthetized materials were studied by mean of XRD, TEM, SEM, TPR and BET methods.
Catalytic oxidation of benzyl alcohol using PdO/CeO2-NR or Pd/ CeO2-NR-H2 was conducted in toluene and in ethanol solvents under air flow (20ml/min). Effect of temperature (60-110 °C), BA concentration and catalyst/BA ratio (1/1, 2/1, 3/1) on catalytic activity and BZ yield was studied. Reactant and products were analyzed by GC-MS.
The results showed that in toluene, catalyst deactivation occurred and high BZ yield was not achieved. In ethanol as solvent, BZ was produced with up to 99% yield and considerable selectivity. The oxidation rate increased with the catalyst/substrate ratio and with the BA concentration
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