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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
Differential splicing of the phospholipid hydroperoxide glutathione peroxidase gene in diploid and haploid male germ cells in the rat
No full textLipoproxidation damage of spermatozoa polyunsatured fatty acids (PUFA): scavenger mechanisms and possible scavenger therapies
No full text“cAMP-response element modulator-τ activates a distinct promoter element for the expression of the phospholipid hydroperoxide/sperm nucleus glutathione peroxidase gene”
No full textPHGPx (phospholipid hydroperoxide glutathione peroxidase) is a
selenoprotein present in at least three isoforms in testis: cytosolic,
mitochondrial and nuclear. All of these derive from the same gene
and are structurally related with the exception of the snPHGPx
(sperm nucleus-specific form), which differs from the others
due to the presence of an arginine-rich N-terminus. It has been
demonstrated recently that this N-terminus is encoded by an alternative
exon located in the first intron of the PHGPx gene. The
expression of snPHGPx has been attributed either to an alternative
pre-mRNA splicing or to the presence of a distinct promoter region.
Nevertheless, the exact molecular mechanism by which the
expression of snPHGPx occurs has not been demonstrated so far.
Preliminary sequence analysis of the region located upstream of
the alternative exon revealed some potential DNA-binding sites,
one of which is specific to the binding of CREM (cAMP-response
elementmodulator) transcription factors. By using electrophoretic
mobility-shift assays, we demonstrated that both nuclear protein
extract from highly purified rat spermatid cells and recombinant
CREM-τ protein can specifically bind to this element. Furthermore,
we cloned a 1059 bp comprising the intron and the alternative
exon for snPHGPx in the pCAT®3 reporter vector. By
transient transfection experiments, we demonstrated that the expression
of the transcription factor CREM-τ can induce the activation
of the reporter gene in NIH-3T3 cell line. These results were
confirmed by chromatin immunoprecipitation experiments performed
on highly purified rat spermatid cells.On the basis of these
results, we demonstrate that snPHGPx expression is mediated
by the transcription factor CREM-τ , which acts as a cis-acting
element localized in the first intron of the PHGPx gene
Liver bromosulphonphthalein transport as a carrier mediated process
No full textLeevy CM (ed): Diseases of the Liver and Biliary Tract. 5th Quadrennial Meeting of the International Association for Study of the Liver, Acapulco, October 1974 With Standardization of Nomenclature, Diagnostic Criteria and Diagnostic Methodology With inserted brochure: Standardization, VI + 60p., broschiert, 197
Enzymatic and immunochemical evaluation of phospholipid glutathione peroxidase (PHGPx) in testis and epididymal spermatozoa of rats of different ages
No full textVariations 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
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