1,720,959 research outputs found
Supporting Electrolyte Bulkiness as a Semiquantitative Probe for Slow Electron Transfer in Dissociative Electron Transfer Studies
No full textAn important model for the study of dissociative electron transfer (DET) is provided by the electrochemical reduction of organic halides, proceeding along either a concerted pathway, electron transfer and bond cleavage occurring in a single step, or a stepwise one, involving the intermediate formation of a radical anion. In the first case the reaction is kinetically controlled by the electron transfer, whereas in the second case two energy barriers must be taken into account.
In a recent investigation on the electrochemical reduction of aryl bromides ArBr on Ag and GC electrodes, we have observed that catalytic Ag significantly modifies the reaction energy profile, making electron transfer more kinetically determining with respect to bond cleavage, and stabilising the reaction products. As a result, in many cases the DET appears to proceed along a stepwise pathway on a non-catalytic electrode such as GC, but along a concerted pathway on catalytic Ag.
In the same mechanistic investigation, when testing the effect of different quaternary ammonium supporting electrolyte cations (with C2, C3, C4 and C6 alkyl chains), we realised that the cation bulkiness, all other experimental conditions being carefully kept constant, not only affects the irreversible electron transfer with the well known shielding effect (the longer the alkyl chains, the slower the electron transfer, with a linear relationship between reduction peak potentials and cation radius), but may be regarded (and, possibly, exploited) as a convenient and effective semiquantitative probe of the kinetic influence of the first electron transfer step in the overall EC process.
In fact, the increase of the shielding effect with the chain bulkiness appears to regularly decrease with increasing aapp. This means that the energy barrier of the chemical step becomes increasingly more determining with respect to that of the electron transfer step. At aapp = 1, i.e. with a process entirely controlled by the chemical step, the supporting electrolyte effect becomes negligible. On the contrary, the largest supporting electrolyte effects were recorded for DET processes that are kinetically controlled by the first electrochemical step.
An exhaustive series of examples in both catalytic and non-catalytic conditions shall be compared and discussed
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
Financial and Business Relationships in Naples during the First Globalization Era (1860-1913). A Network Analysis perspective.
No full textHow the relations among business actors in Naples evolved over the Italian Political Unification? How the role of (local, national and international) finance and its interconnections to the local business network evolved when the space of relationships widened, since Italy became a nation-state and the international market structure was rapidly reshaping within the first globalisation process?
We use Network Analysis tools: i) to visually explore relational patterns among business actors before and after the Italian Political Unification; ii) to highlight actors’ homophily behaviors considering firm’s sector and localization; and iii) to discover the presence
of core actors playing central and brokerage roles
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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