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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
Evaluation of the impact of vitrification on the actin cytoskeleton of in vitro matured ovine oocytes by means of Raman microspectroscopy.
Get PDFPurpose Investigation of the changes induced by vitrification
on the cortical F-actin of in vitro matured ovine oocytes by
Raman microspectroscopy (RMS).
Methods Cumulus-oocyte complexes, recovered from the
ovaries of slaughtered sheep, were matured in vitro and vitrified
following the Minimum Essential Volume method using
cryotops. The cortical region of metaphase II (MII) oocytes
(1) exposed to vitrification solutions but not cryopreserved
(CPA-exp), (2) vitrified/warmed (VITRI), and (3) untreated
(CTR) was analyzed by RMS. A chemical map of one quadrant
of single CPA-exp, VITRI and CTR oocytes was, also,
performed. In order to identify the region of Raman spectra
representative of the cortical F-actin modification, a group of
in vitro matured oocytes were incubated with latrunculin–A
(LATA), a specific F-actin destabilizing drug, and processed for
RMS analysis. Thereafter, all the oocytes were stained with
rhodamine phalloidin and evaluated by fluorescence confocal
microscopy. Raman spectra of the oocytes were, statistically,
analyzed using Principal Component Analysis (PCA).
Results The PCA score plots showed a marked discrimination
between CTR oocytes and CPA-exp/ VITRI groups. The main
differences, highlighted by PCA loadings, were referable to
proteins (1657, 1440 and 1300 cm−1) and, as indicated by
LATA experiments, also included the changes of the F-actin.
Analysis by confocal microscopy revealed a clear alteration of
the cortical F-actin of CPA-exp and VITRI oocytes
confirming RMS results.
Conclusions Raman microspectroscopy may represent an
alternative analytical tool for investigating the biochemical
modification of the oocyte cortex, including the F-actin cytoskeleton,
during vitrification of in vitro matured ovine oocytes
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
Raman spectroscopy-based approach to detect aging-related oxidative damage in the mouse oocyte
No full textMetodiche non invasive per la valutazione del danno ossidativo in ovociti di mammifero: possibili applicazioni della spetroscopia Raman
No full textExpression of maternally derived KHDC3, NLRP5, OOEP and TLE6 is associated with oocyte developmental competence in the ovine species.
No full textRaman microspectroscopy as a non-invasive tool to assess the oxidative stress of mouse oocyte
No full textAnalisi mediante microspettroscopia Raman delle alterazioni biochimico-molecolari indotte dallo stress ossidativo nell’oocita di topo
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