1,720,985 research outputs found
Electronic-structure of Transition-metal Tetracoordinated Complexes .1. Theoretical Abinitio and Uv-photoelectron Spectroscopy Study of Palladium(II) and Platinum(II) Square-planar Acetylacetonate Complexes
No full textAn Accurate Dv X-alpha Investigation of the Electronic-structure of Bis(2,4-pentanedionato)palladium(ii)
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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
Photoelectron spectroscopy of f-element organometallic complexes. 9. A comparative fully relativistic/nonrelativistic first-principles X.alpha.-DVM and photoelectron spectroscopic investigation of electronic structure in homologous 4f and 5f tris(.eta.5-cyclopentadienyl)metal(IV) alkoxide complexes
No full textThe electronic structure of (eta5-C5H5)3MOR (M = Ce, Th, U) complexes has been investigated by He I and He II UV photoelectron spectroscopy combined with SCF Xalpha-DVM calculations. Fully relativistic Dirac-Slater calculations were also carried out for the M = Th complex. The nonrelativistic calculations indicate that metal-ligand interactions involving the highest energy ligand orbitals involve primarily metal 5f orbitals while 6d admixtures are found for lower energy orbitals. The M-O bonding is both sigma and pi in nature and involves primarily metal 6d atomic orbitals. Evidence of a charge redistribution mechanism along the CH3 --> O --> M --> Cp3 direction provides a satisfactory explanation for the shortened M-O distances and strong propensity for nearly linear M-O-CH3 linkages observed in diffraction studies. The fully relativistic calculations show that metal d contributions are slightly underestimated at the nonrelativistic level. Such deviations do not, however, alter the overall description of the metal-ligand bonding. The nonrelativistic configuration of the metal center compares well with the relativistic data. Gas-phase ionization energies can be accurately and comparably evaluated at the computationally more efficient nonrelativistic level if optimized basis sets and potential representations are used
Photoelectron spectroscopy of f-element organometallic complexes. 6. Electronic structure of tetrakis(cyclopentadienyl) actinide complexes
No full textA description of the electronic structure of M(.eta.5-C5H4CH3)4 (M = Th, U) complexes as based upon He I and He II photoelectron spectra and relativistic Xa-SW calculations is presented. Despite the true S4 symmetry of the molecules, the outermost MO’s are grouped as if the complexes have a pure tetrahedral ligation environment. As a consequence, donation to empty metal orbitals appears to be highly dominated by the symmetry requirements. The HOMO in Cp’,U is almost pure 5f in character, and the corresponding 2F5/2 final state produced upon ionization is split by operation of a Td ligand field. The relative intensity variations
observed on passing from He I to He II spectra are quite unexpected. It appears that the He I1 increases of PE signals due to MO’s having large metal 6d character are greater than those due to MO’s having comparable 5f admixture
Dispelling 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
Electronic-structure of Tetracoordinate Transition-metal Complexes .2. Comparative Theoretical Abinitio Hartree-fock-slater and Uv-photoelectron Spectroscopic Studies of Building-blocks For Low-dimensional Conductors - Glyoximate Complexes of Palladium(ii) and Platinum(ii)
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