1,720,955 research outputs found
Electrochemical behaviour of cobalta-dicarbollide sandwich complexes with different capping units
No full textThe redox aptitude of a series of cobalt(III) or cobalt(I) sandwich complexes bearing a charge compensated dicarbollide ligand ([9-L-7,8-C 2B9H10]-) as a constant unit and different counterparts (varying from classical [7,8-C2B 9H11]2- to charge-compensated [9-L-7,8-C 2B9H10]- dicarbollides, from cyclopentadienyl [C5R5]- (R = Me, H) to cyclobutadiene [C4Me4]0 ligands) has been studied. All the Co(III) complexes display the reversible sequence Co(III)/Co(II)/Co(I). In contrast, the Co(I) complexes (namely, those capped by tetramethylcyclobutadiene) accede reversibly only to the Co(II) oxidation state, the passage to Co(III) being irreversible. When possible, the Co(II) intermediates have been characterized by EPR spectroscopy. The molecular structures of the monocation [Co(η-9-SMe2-7,8-C2B 9H10)2]+ in its DD/LL and meso diastereomeric forms as well as that of heteroleptic (η-7,8-C 2B9H11)Co(η-9-SMe2-7,8-C 2B9H10) have been obtained by single-crystal diffraction. © Springer-Verlag 2005
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
(Tetramethylcyclobutadiene)cobalt complexes with monoanionic carborane ligands [9-L-7,8-C2B9H10]- (L = SMe2, NMe3 and py)
No full textnido-Carborane 9-NMe3-7,8-C2B9H 11 (2c) was synthesized by CuSO4 oxidation of anion [7,8-C2B9H12]- in the presence of [Me3NH]+ in aqueous ammonia. Improved procedures for the preparation of nido-carboranes 9-SMe2-7,8-R2-7,8-C 2B9H9 (2a: R = H; 2b: R = Me) and 9-py-7,8-C2B9H11 (2d) were developed. nido-Carborane monoanions [9-L-7,8-R2-7,8-C2B 9H8]- (1a-1d), generated by deprotonation of 2a-2d by NaH, react with Cb*Co(CO)2I or [Cb*Co(MeCN) 3]+ (Cb* = C4Me4) to give complexes Cb*Co(η-9-L-7,8-R2-7,8-C2B 9H8) (3a-3d). The structures of carborane 2d and complexes 3a and 3d were determined by X-ray diffraction. Electrochemistry of the cobalt complexes was studied. © 2005 Elsevier B.V. All rights reserved
Synthesis, structure, electrochemistry, and metal-atom dynamics of cyclopentadienyl ferracarboranes
No full textA series of metallacarboranes, incorporating the CpFe fragment, were studied by electrochemical techniques, temperature-dependent Mössbauer effect (ME) spectroscopy, and X-ray diffraction. The compounds studied include the parent dicarbollide complex CpFeC2B9H11 (1) and its reduced form [1]-, the charge-compensated ferradicarbollides 1-Cp-4-L-1,2,3-FeC2B9H10 [L = SMe2 (2a), NMe3 (2b), py (2c)] and their methylated analogs 1-Cp-2,3-Me2-4-SMe2-1,2,3-FeC2B 9H8 (2d) and 1-Cp*-4-SMe2-1,2,3-FeC 2B9H10 (2e), the isomeric ferratricarbollides CpFeC3B8H11 (3a-c), and the amino-substituted derivative 1-Cp-12-tBuNH-1,2,4,12-FeC3B8H10 (3d). The ferradicarbollides 2a-e were synthesized by reactions of the charge-compensated dicarbollide anions [9-L-7,8-R2-7,8-C 2B9H8]- (R = H, Me) with [(C 5R5)-Fe(MeCN)3]+ cations. The structures of 1, [NMe3Ph][1], and 2b were investigated by X-ray diffraction. The ME spectroscopic study elucidated the relationship between the nature of the five-membered carborane face coordinated to the metal center and the hyperfine interaction parameters of the Fe atom. Temperature-dependent recoil-free fraction studies yielded the root-mean-square-amplitude-of-vibration (rmsav) of the metal atom over a wide temperature range, which proved to be in good agreement with cristallographic Ui,j data for 1 and 3a,b. Electrochemistry shows that the isomeric ferratricarbollides 3a-c undergo reversible oxidation to the corresponding FeIII derivatives at potential values higher, on average, by about 0.4 V than those of the charge-compensated complexes 2a-c and by about 0.8 V than that of the parent ferradicarbollide [1]-. This result indicates the strong electron-withdrawing ability of the extra carbon atom relative to that of the replaced boron atom. As a consequence of the shift of the HOMO-LUMO frontier orbitals to the high energy levels, the FeII/FeI reduction becomes accessible. © Wiley-VCH Verlag GmbH & Co. KGaA, 2006
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
- …
