1,721,038 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
Trichlorotin(II)–(meso-Tetraphenylporphyrinato)rhodium(III), a Porphyrin Derivative with an Rh—Sn Bond
No full textThe structure of the title compound, trichloro-2 kappa(3)Cl-(5,10,15,20-tetraphenylporphyrinato- 1 kappa(4)N(21,22,)(23,24))rhodium(III)tin(II)(Rh-Sn), [RhSnCl3(C44H28N4)], consists of well separated units in which the Rh atom is five-coordinate at the center of a square-pyramidal polyhedron with the Sn atom at the top. The macrocylic unit is planar with the Rh atom displaced by only 0.02 Angstrom from the ring plane. The Rh-Sn bond length is 2.450 (1) Angstrom
Reactions of palladium(II) allyl dimers with palladium(II) complexes containing σ-bonded 1,2-bis(imino)alkyl groups. Crystal and molecular structure of the zwitterionic binuclear compound [Pd(η3-2-MeC3H4){R1NC(PdCl2L)–CMeNR2}](L = PPh3, R1= R2= C6H4OMe-p)
No full textVariations 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
Redox mechanism and cycling behaviour of nonylbenzo-hexaquinone electrodes in Li cells
No full textNonylbenzo-hexaquinone (NBHQ), a quinonoid polymer of low molecular weight, has been reinvestigated as a cathode material for Li cells. Its reduction mechanism gives rise at first, in a 3-electron process, to an irreversible species involving the formation of radical anion. Successively, a direct two-electron reduction of other quinone groups occurs. This second step, witch involve 4 e- in quasi-thermodynamic conditions, is reversible and allows cells of the type Li/LiClO4-PC.DME/NBHQ,C to be cycled for more than 500 cycles at the c/2 rate between 3.5 and 2.0 V. The average energy density during this cycling was 160 Wh/kg, based on the weight of the cathode material (additive included)
First Direct Synthesis of a Corrole Ring From a Monopyrrolic Precursor. Crystal and Molecular Structure of (Triphenylphosphine)(5,10,15-triphenyl-2,3,7,8,12,13,17,18-octamethylcorrolato)cobalt(III)-Dichloromethane
No full textThe first synthesis of the corrole ring by self-condensation of a monopyrrolic unit is reported. The reaction occurs only in the presence of cobalt ions; it leads to the formation of (triphenylphosphine)(5,10,15-triphenyl-2,3,7,8,12, 13,17,18-octamethylcorrolato)cobalt(III), [Co(OMTPC)PPh3] and represents the first example of interconversion between a porphyrinoid and a corrole structure. Crystals of [Co(OMTPC)PPh3].CH2Cl2 have been obtained by slow diffusion of methanol into a dichloromethane solution of the complex and have been characterized by single-crystal X-ray analysis. They crystallize in the triclinic system, space group P1BAR, with a = 10.628 (2) angstrom, b = 11.585(2) angstrom, c = 22.352(4) angstrom, alpha = 84.93(2)-degrees, beta = 78.56(2)-degrees, gamma = 72.93(2)-degrees, and Z = 2. The structure was solved by heavy-atom methods and refined by least-square techniques to R = 0.051 for 6377 unique data [F(o) > 4 sigma(F(o))]. The analysis reveals the substantial planarity of the macrocyclic ring. In the 23-atom core of the corrole moiety each atom shows an average displacement from the plane of best fit of 0.14 angstrom, with the largest deviations being +0.33 and -0.33 angstrom for C(2) and C(12), respectively. The synthesis of diphenyl derivatives of corrole: (triphenylphosphine) (5,10-diphenyl-2,3,7,8,12,13,17,18-octamethylcorrolato)cobalt(III), [Co(5,10-OMDPC)PPh3], and (triphenylphosphine) (5,15-diphenyl-2,3,7,8,12,13,17,18-octamethylcorrolato)cobalt(III), [Co(5,15-OMDPC)PPh3], is also reported. Plausible reaction pathways leading to the formation of the two isomers are discussed together with the spectral properties of the complexes
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
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