1,720,965 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
Electrochemistry and spectral characterization of oxidized and reduced (TPPBrx)FeCl where TPPBrx is the dianion of beta-brominated-pyrrole tetraphenylporphyrin and x varies from 0 to 8
No full textThe electrochemistry and spectroelectrochemistry of (TPPBrx)FeCl (TPPBrx is the dianion of beta-brominated-pyrrole tetraphenylporphyrin and x = 0-8) were examined in PhCN containing tetra-n-butylammonium perchlorate (TBAP) as supporting electrolyte. Each compound undergoes two reversible to quasireversible one-electron oxidations and either three or four reductions within the potential limits of the solvent. The two oxidations occur at the conjugated porphyrin pi ring system, and Delta E(1/2) between these two electrode reactions increases as the molecule becomes more distorted. The overall reduction of each compound involves the stepwise electrogeneration of an iron(II), iron(I), and iron(I) pi anion radical. An equilibrium between chloride-bound and chloride-free iron(II) forms of the porphyrin is observed with association of the anionic ligand being favored for compounds with x > 5. Singly reduced (TPPBrx)FeCl (x = 0 to x = 6) forms both mono- and bis-CO adducts in CH2Cl2. Only the mono-CO adduct is observed for (TPPBr7)FeCl, and there is no binding at all of CO to (TPPBr8)FeCl. The nu(CO) of both the mono- and bis-adducts increases with increase in the number of Br groups, but in a nonlinear fashion which is explained in terms of two competing effects. One is the electron-withdrawing affinity of the Br substitutents and the other the nonplanarity of the macrocycle
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
Synthesis, structure, and electrochemistry of an electron deficient mu-oxo porphyrindimer, [(TPPBr4)Fe]O-2
No full textThe synthesis and structural and electrochemical properties of an electron deficient iron mu-oxo porphyrin dimer, (mu-oxo)bis[(2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrinatoiron(III)), represented as [(TPPBr4)Fe]O-2, are reported. X-ray analysis indicates an FE-O-Fe angle of 177.4(5)degrees and an interplanar distance of 4.58 Angstrom between the two mean porphyrin planes. Opposite pyrrole rings on the same macrocycle are twisted by about 25 degrees relative to each other so that the porphyrin skeleton distortion is best described as a twisted saddle-shaped configuration. Electrochemical studies reveal that the highly halogenated mu-oxo dimer is stable in PhCN and undergoes four one-electron oxidations and four one-electron reductions in a total of seven steps. The singly reduced and singly oxidized forms of the dimer were characterized by thin-layer spectroelectrochemistry and ESR spectroscopy
Synthesis and electrochemistry of 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetrakis(3,5-dichloro-2,6-dimethoxyphenyl)porphyrin(H(2)tdcdmpp), [Co-II(tdcdmpp)] and [M(tdcdmpp)Cl] (M=Fe-III or Mn-III)
No full textFour new highly chlorinated porphyrins, 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetrakis(3,5-dichloro-2,6-dimethoxyphenyl)porphyrin (H(2)tdcdmpp), [Co-II(tdcdmpp)] and [M(tdcdmpp)Cl] (M = Fe-III or Mn-III) have been prepared. The free base was synthesized by chlorination of H(2)tdmpp [5,10,15,20-tetrakis(2,6-dimethoxyphenyl)porphyrin] and metallated to give the complexes following published procedures. The same transition-metal derivatives of tdmpp were also prepared and all eight synthesized compounds were electrochemically investigated in benzonitrile or pyridine containing 0.1 mol dm(-3) NBu(4)(n)ClO(4). As expected the half-wave potentials of the tdcdmpp complexes are shifted towards positive values while those for oxidation or reduction of the tdmpp species are shifted negatively as compared with E(1/2) for oxidation or reduction of tetraphenylporphyrin (tpp) complexes having the same central metal ions. The magnitude of the anodic shifts in E(1/2) for reduction with respect to pp is among the largest reported for chlorinated porphyrins and ranges between 590 and 860 mV depending upon the specific redox reaction and solvent. A smaller Delta E(1/2) of 330-400 mV is seen for oxidation of the same compounds and these values can be compared to a negligible shift in E(1/2) upon going from planar M(tpp) to distorted M(obtpp) (obtpp = 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrinate) complexes of cobalt and iron where the effect of macrocycle ruffling is known to predominate over the electronic effects of added halide substituents. This result indicates that the core distortion cannot compensate totally for the electron-withdrawing effect of the Cl substituents. The macrocyclic distortion also induces a large red shift of the UV/VIS absorption bands and this shift in lambda(max) ranges up to 40 nm for the chlorinated compounds with respect to the tdmpp complexes
- …
