1,720,987 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
Disordini temporo-mandibolari: valutazione clinica degli effetti terapeutici della placca funzionale bite
No full textImpiego di una placca funzionalizzante per il trattamento del dislocamento anteriore del disco senza riduzione
No full textGenetic control of in vitro organogenesis in Petunia x hybrida Hort.
No full textDespite the fact that Petunia x hybrida plant has become a model plant in genetic field, there are few reports about genetic model of in vitro organogenesis. The aim of the present project was to formulate a hypothesis on the number of genes involved in the control of in vitro organogenesis in Petunia x hybrida. In previous experiments, we had already
characterised 16 pure genotypes for their performances in vitro. Among them, we chose two lines, here reported as “K” and “L”, that showed opposite behaviours in culture. Line K showed the best performance, whilst line L was the worst for each of the following characters: callus formation ability (97.8%; 76.7% respectively), organogenesis ability (80.7%; 36.2% respectively) and average number of differentiated shoots per explant (6.7 ± 4.6; 2.6 ± 1.9 respectively). Reciprocal crosses between these lines were performed; further, leaf explants of F1 progenies (KxL; LxK) were induced to differentiate in vitro on Murashige and Skoog medium added with 30 gl-1 sucrose, 0.2 mgl-1 IAA, and 1.0 mgl-1 BAP, pH 5.8. Data on callus proliferation, explant shoot
differentiation and number of differentiated shoots per explant were scored after 7, 14, 21, 28, 34 and 41 days of in vitro culture. The frequencies of explants producing callus in each F1 progeny (100.0% and 96.0%) were similar to the parental K genotype, but callus proliferation happened earlier than the parental K line. These results suggested the involvement of dominant and additive genes. Interestingly,
the frequencies of leaf explant differentiation (94.0% and 91.7%) and the average number of shoots per differentiated explant (11.6 ± 4.9 and 9.7 ± 4.1) outperformed the values observed in the line K, hence suggesting a heterosis effect. Moreover, the progenies of the two reciprocal crosses showed
significant differences for each of the above mentioned characters, suggesting a maternal effect.
F2 seeds, obtained after self cross of F1 plants (KxL or LxK hybrids) were sown in vitro. Twenty one seedlings per each reciprocal cross progeny were collected and their leaves were cultured on the above mentioned differentiation medium. Data score, carried out as for the F1 progeny, was performed per each F2 progeny. The frequency of callus proliferation observed in both F2 progeny was according to a segregation rate of 13:3. This result suggested the involvement of two loci with a dominant and recessive epistatic action. In contrast, a segregation rate of 9:7 was observed in the
frequency of explants differentiated shoots. This segregation rate was according to a genetic model of two complementary loci. Finally, segregation rate of F2 progeny which were differentiated a high or a low number of shoots per differentiated explant was doubtful. Result allowed us to hypothesize the presence of two epistatic loci but was not possible to understand what kind of epistatic interaction was present
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