1,721,068 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
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
Impiego di una tecnica respiromentrica per al valutazione dell’attività microbica nei suoli contaminati
No full textStereochemical studies on the interconversion of alkylidenecarbene, carbene, and alkyl ligands in chiral cyclopentadienyl ruthenium complexes
No full textPseudotetrahedral (S,S)-(η-C5H5)RuPh2PCH(CH 3)CH(CH3)PPh2Cl (1), (SRu,RC)-1′a, and (RRu,RC)-(η-C5H5)RuPh 2PCH(CH3)CH2PPh2Cl (1′b) have been used to investigate the stereochemistry of alkylidenecarbene and carbene formation. Depending on conditions 1′a and 1′b can react stereospecifically with terminal acetylenes, in the presence of halogen scavengers, to give the corresponding alkylidene complexes [Ru=C=CHR]PF6 (R = C6H5,2′a and 2′b; R = CH3, 6′a and 6′b). Retention of configuration at ruthenium was confirmed by an X-ray crystal structure of 6′a. 2′a and 2′b are converted with base to the corresponding phenylacetylide complexes RuC≡CC6H5 (5′a and 5′b), which, in turn, regenerated 2′a and 2′b on reaction with HPF6. Neither reaction changes the stereochemistry at the metal. 2′a and 2′b react further with CH3OH stereospecifically and with retention of the configuration at ruthenium to give the methoxycarbene complexes [Ru=C(OCH3)CH2C6H5]PF6 (3′a and 3′b). The crystal structure of 3′b has also been determined. 3′a and 3′b react with LiAlH4 in THF at low temperature to give the 2-phenylethyl complexes RuC-H2CH2C6H5 (4′a and 4′b) with retention of configuration. Labeling studies have demonstrated that the two hydrogen atoms of the new formed methylene group arise from LiAlH4. The summary of crystal data is as follows. For 6′a: a = 11.469 (4) Å, b = 14.976 (4) Å, and c = 20.696 (7) Å with Z = 4 in space group P212121 (no. 19). For 3′b: a = 12.555 (4) Å, b = 12.651 (4) Å, and c = 24.198 (8) Å with Z = 4 in space group P212121 (no. 19)
- …
