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Reproductive strategy of the Nearctic leafhopper Scaphoideus titanus Ball (Hemiptera: Cicadellidae)
No full textVibrational communication and other behavioural traits in Scaphoideus titanus Ball (Hemiptera: Cicadellidae)
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Reproductive strategy of the Nearctic leafhopper Scaphoideus titanus Ball (Hemiptera: Cicadellidae)
No full textMating behaviour of Scaphoideus titanus Ball, the vector of the grapevine disease
Flavescence dore ́e, was investigated in order to determine the role of substrateborne
vibrational signals in intra-specific communication and pair formation.
Vibrational signals were recorded from grapevine leaves with a laser vibrometer.
Signalling activity of single males changed throughout the day and the peak in
activity was associated with twilight and early night when ‘call and fly’ behaviour
was observed. Pair formation began with the spontaneous emission of male
signals. The male calling signal consisted of a single series of pulses, partially
accompanied with a ‘rumble’. The male courtship phrase consisted of four
consecutive sections characterized by two sound elements, pulse and ‘buzz’.
Female vibrational signals were emitted only in response to male signals. The
female response was a single pulse that closely resembled male pulses and was
inserted between pulses within the male signals. All recorded vibrational signals of
S. titanus have a dominant frequency below 900 Hz. A unique feature of vibrational
communication in S. titanus is well-developed intrasexual competition; males may
use alternative tactics, in the form of disturbance signals, or silently approach
duetting females (satellite behaviour). While the male-female duet appears to be
essential for successful localization of females and copulation, it is also vulnerable
to, and easily disrupted by, alternative tactics like masking
Disruption of the reproductive behaviour of Scaphoideus titanus by playback of vibrational signals
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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
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
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