1,721,002 research outputs found
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
Breeding Ecology of Two Species of Forest-Falcons (Micrastur) in Northeastern Guatemala
No full textI studied the breeding biology, food habits, and home ranges of the Barred Forest-Falcon (Micrastur ruficollis) and the Collared Forest-Falcon (M. semitorquatus) in Tikal National Park of northeastern Guatemala from 1988 to 1992. Barred and Collared Forest-Falcons are residents and maintain territories throughout the year.
Barred Forest-Falcon breeding coincides with the end of the dry and beginning of the wet seasons. Nesting sites were occupied in April, May, and June and average reoccupancy rate was 86%. Thirty-eight nests were located in tree cavities. The onset of egg-laying was in mid April to early June. The incubation period was 37 days from laying of the first egg to hatch (n=6 nests) and the average age of fledging was 38.3 days (SD±3.3, range=35-44 days). Fledging occurred in July and August. Of 34 fully documented nesting attempts 16 (47%) produced young. A total of 1.1 young fledged per breeding attempt. Most reproductive losses in 17 nests resulted from egg predation (n=ll). Survivability of adult breeding females was less than that for males. Food habits were based on 600 prey deliveries during the breeding season. On a numerical basis, lizards made up 40.8% (n=245) and birds 14.6% (n=88) of the diet. Biomass estimates showed lizards 37.3% and birds 36.8% to be the most important prey items delivered during the breeding season. Home range estimates of 85 harmonic means averaged 114.6±28.8 ha for breeding males (n=ll).
Collared Forest-Falcon breeding occurs at the end of the rainy season through the dry season to the beginning of the rainy season in June and July. Nesting sites were occupied in February and March. Eight nests were located, seven in Tikal and one outside the park. Laying occurred in late February to mid May. The incubation period was 47 days (n=l nest) and the average age of young fledging was 50.0±4.2 days (ranging from 46 to 56 days). Fledging occurred in June. Overall reproductive success was 57% (4 nests fledged young out of 7 attempts). Productivity was 1.0 young fledged per breeding attempt. Nest failures were caused by predation on eggs. Food habits were based on 258 prey items delivered during the breeding season. On a numerical basis (n=222 prey items) mammals 35.1% (n=78) and birds 26.5% (n=59) made up the major proportion of the diet. Biomass estimates showed mammals 45.6% and birds 49.4% to be the most important prey delivered during the breeding seasons. An extra adult took over parental duties of feeding fledglings in 1990 and delivered 36 prey items. Home range estimates for the 85% harmonic means averaged 877.6±301.6 ha for males (n=3, two breeding and one nonbreeding) and 712.0±578.7 ha for females (n=4, one breeding and three nonbreeding)
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
Comments on the first nesting record of the nest of a Slaty-backed Forest-Falcon (Micrastur mirandollei) in the Ecuadorian Amazon
No full textVolume: 36Start Page: 335End Page: 33
Nest-site Characteristics and Breeding Density of Two Sympatric Forest-falcons in Guatemala
No full textThe Food Habits of Sympatric Forest-falcons During the Breeding Season in Northeastern Guatemala
No full textThe food habits of sympatric Forest-Falcons during the breeding season in northeastern Guatemala
No full textVolume: 34Start Page: 196End Page: 20
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
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