1,721,002 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
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
Linear Oligopeptides .292. 1st Characterization At Atomic-resolution of the C-activating Groups In A Peptide-synthesis Acid Chloride, Acid Azide and Carboxylic Carboxylic Mixed Anhydride
No full textThe X-ray diffraction structures of three N(alpha)-protected, C(alpha)-activated MeAib derivatives are reported. They are Tos-MeAib-Cl, Tos-MeAib-N3 and Tos-MeAib-O-Piv. The geometry and conformation of these classical carboxyl activating groups, which have been characterized at atomic resolution for the first time, are discussed
Reactive Intermediates in Peptide Synthesis. Molecular and Crystal Structures of Reactive Carboxylic Amides
No full textThe molecular and crystal structures of N-para-toluenesulphonyl-N-methyl-alpha-aminoisobutyric acyl imidazole (1), and 3-(N-para-toluenesulphonyl-alpha-aminoisobutyric acyl)-1,3-thiazolidine-2-thione (2) have been determined by X-ray diffraction. Crystal parameters: (1) orthorhombic, space group P2(1)2(1)2(1), a = 11.735(2) Angstrom, b = 19.990(3) Angstrom, c = 6.925(1) Angstrom, and Z = 4; (2) orthorhombic, space group Pnc2, a = 9.507(2) Angstrom, b = 16.902(2) Angstrom, c = 10.347(2) Angstrom, and Z = 4. The structures were solved by direct methods. The least-squares refinements led to conventional R factors of 0.036 and 0.031 for (1) and (2), respectively. This is the first geometrical and conformational characterization at atomic resolution of N-alpha-protected alpha-aminoacids containing the elusive acyl imidazole and 3-acyl-1,3-thiazolidine-2-thione C-activating groups. Only the reactive carboxylic amide of (2) deviates significantly from planarity
First 3-d Structure Determination of A Peptide Oxazol-5(4h)-one With A Chiral Protein Amino-acid In the Heterocyclic Moiety - An X-ray-diffraction Analysis of the Enantiomeric and Racemic Goodman Oxazolone
No full textThe x-ray diffraction structure analyses of the L-enantiomeric and racemic forms of the 2-(1'-benzyloxycarbonylamino-1'-methyl) ethyl-4-benzyl-oxazol-5(4H)-one, the Goodman oxazolone, have been performed. In the crystal state the oxazolone ring of the enantiomeric compound is nearly sandwiched between the two phenyl rings, whereas in the racemate the phenyl ring of the N-alpha-protecting group moves away from the oxazolone ring
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
Molecular and crystal structure of a terminally protected, folded tripeptide
No full textThe molecular and crystal structure of the terminally protected tripeptide N-benzyloxycarbonyl-alpha-aminoisobutyryl-L-phenylalanyl-L-alanine methyl ester has been determined by X-ray diffraction. Crystal parameters: orthorhombic, space group P2(1)2(1)2(1), a = 11.542(2) Angstrom, b = 23.806(3) Angstrom, c = 8.987(2) Angstrom, and Z = 4. The crystal structure was solved by direct methods. The least-squares refinement led to R(1) = 0.039 [on F greater than or equal to 4 sigma(F)] and wR(2) = 0.127 (on F-2, all data). The -Aib-L-Phe- sequence of the tripeptide is folded into a type-I beta-bend conformation
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
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