1,720,975 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
Calculation of the proton and electron affinity of simple Ge-containing species using density functional theory
No full textBasis sets developed using the generator coordinate method and a pseudopotential have been adapted to density functional theory to calculate the proton affinity of GeH4, GeH3-, GeF3-, CH3GeH2-, and Ge(OH)(3)(-) and the electron affinity of .GeH3 and .GeF3. The proton affinity of GeH4 is calculated to be 673.9 kJ mol(-1) at 298 K, while values for GeH3- (1505.0 kJ mol(-1)) and CH3GeH2- (1529.0 kJ mol(-1)) are in excellent agreement with experimental values. The electron affinity of .GeF3 is predicted to be in the range of 3.5-3.7 eV by calculations using different functionals and ab initio methods. The present calculations reveal that the B3P86 method can yield proton affinities comparable to those obtained with other high-quality methods but consistently overestimates electron affinities of simple Ge radicals.10250103991040
Enthalpies Of Formation Of Phosphorus And Oxygen Compounds Determined By The Correlation Consistent Composite Approach
No full textThe heats of formation of small molecules (O 2, O 3, P 2, P 4, PO, PO 2, PO 3, P 2O, P 2O 2, and P 4O 6) have been determined by a modified version of the correlation consistent composite approach (ccCA). The equilibrium geometries and vibrational frequencies were computed via density functional theory, using the M06-2X exchange-correlation functional and 6-31G(2df,p) basis sets. The original methodology requires CCSD(T) energy, which now is obtained by CR-CCSD(T)-L method. The theoretical heats of formation, whose accuracy is estimated as ranging from ±4 to ±10 kJ mol -1, are closer to the available experimental data, but O 3 and P 4O 6 are exceptions, exceed the desired value of ±10 kJ mol -1. The ccCA result for ozone (159.2 kJ mol -1) shows a deviation in comparison to experimental data (142.67 ± 1.7 kJ mol -1), but it is closer to the calculated value 154.0 kJ mol -1 by the high-level quantum chemical calculation (W1U; Janoschek and Fabian, J. Mol. Struct. 2006, 780-781, 80). The value of heat formation to P 4O 6 was estimated to be -1706.3 kJ mol -1. This value is quite different of experimental data, and additional studies are needed to understand this deviation. © 2012 Wiley Periodicals, Inc. Products obtained from reactions between oxygen atoms and phosphorous compounds can be useful for many applications such as laser systems, catalysts, involving ligands in asymmetric metal catalysis, and so forth. So, the acquisition of quantitative characteristics for electronic structure of these compounds is very useful. The thermochemical parameters, such as free energy, heat, and entropy of formation, are the essential properties for the determination of the strength of the chemical bonds associated with these molecular systems. Copyright © 2012 Wiley Periodicals, Inc.1121932563260Luehr, S., Holz, J., Boerner, A., (2011) Chem. Catal. Chem., 3, p. 1708Braga, A.A.C., Morgon, N.H., Ujaque, G., Maseras, F., (2005) J. Am. Chem. 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Quantum theoretical model for the physical adsorption of He by solid Xe.
No full textThis article introduces a simplified model for the theoretical study of the physical adsorption process of gaseous He on the planes (100) and (111) of the solid Xe matrix, whose crystalline structure is face centered cubic (fcc). The Al, initio calculations were carried out at the MP2 level of theory employing basis sets obtained through the Generator Coordinate Method, where the core electrons were represented by a pseudopotential. The calculated adsorption energies for the (100) and (111) faces are 5,39 and 4,18 kJ/mol, respectively. This simplified model is expected to be suitable for treating complex systems of applied interest.21325926
Electron affinity of XnGe(OMe)(3-n) radicals (X = H, F; n=0-2) and the Ge-H bond dissociation energy
No full textThe recent observation of a number of gas-phase germyl anions of the type XnGe(OMe)(3-n)(-) (X = H, F; n = 0-2), suggests that these species are very stable and relatively unreactive in ion/molecule reactions. We report the electron affinity of the corresponding XnGe(OME)(3-n) radicals calculated at the QCISD(T) level using basis sets developed by the generator coordinate method and adapted to effective core potentials. These calculations show the electron affinity increasing in the order GeH3 (1.55 eV) < H2GeOMe (1.75 eV) < HGe(OMe)(2) (1.95 eV) < Ge(OMe)(3) (2.32 eV) < FGe(OMe)(2) (2.67 eV) < F2GeOMe (3.12 eV), and are estimated to be within 0.10-0.15 eV (for the radicals at the upper end) of the true adiabatic values. Ge-H bond energies have also been calculated for some of the simpler systems and the 81.1 kcal mol(-1) BDE0 K calculated for H3Ge-H is in very good agreement with the recommended experimental value of 82 +/- 2 kcal mol(-1). (C) 2001 Elsevier Science B.V.21041699SI17318
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
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