1,720,996 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
The fate of Hancock II porcine valve recipients 25 years after implant.
No full textObjective: The Hancock II (HII) is a second-generation porcine bioprosthesis introduced into clinical use in 1982. This study aimed to evaluate very long-term outcomes for the HII valve in a large patient population. Methods: Between May 1983 and November 1993, 517 consecutive patients (pts) (309 male, mean age: 64 ± 9 years) underwent valve replacement (VR) surgery with HII, with 302 (58.4%) in the aortic VR (AVR) and 215 (41.6%) in the mitral VR (MVR) position, respectively. At implant, 106 pts (20.5%) were <60 years of age (G1), while 411 (79.5%) were ≥60 years of age (G2). The 25-year follow-up was complete for all pts at a median of 12 years (range: 0–25). Results: Long-term death occurred in 208 AVR and in 165 MVR pts. Survival at 15 and 20 years was 39.5% and 23.3% in AVR pts and 39.0% and 15.8% in MVR pts. At 25 years the survival of MVR pts was 13.7% (four pts at risk). Late freedom from re-operation was 85.5% and 79.3% at 15 and 20 years in the AVR pts and 73.3% and 52.8% in the MVR pts, respectively. In the AVR population, 20-year freedom from re-operation was 52.2% in G1 pts and 86.8% in G2 pts (p < 0.0001), while in the MVR population it was 41.4% in G1 pts and 61.9% in G2 pts (p = 0.201), respectively. Conclusions: These results confirm the excellent long-term performance of the HII bioprosthesis
Vincenzo Gallucci: Memories of a Surgeon, Scientist, and Teacher
No full textThirty years ago, Vincenzo Gallucci, MD, head of the Cardiovascular Surgery Institute of the University of Padua Medical School in Italy, died in a car accident at the age of 55 years. Vincenzo Gallucci was one of the most authoritative Italian cardiac surgeons, a fine, gentle, and extremely talented surgeon. He is credited with the first implant of a glutaraldehyde-fixed, stented porcine Hancock bioprosthesis in 1970 and with the first orthotopic heart transplantation performed in Italy in 1985. After 30 years, the memory of a great surgeon, scientist, and teacher is still alive, particularly in those who received his important heritage
- …
