1,721,114 research outputs found
Occurrence of leafhoppers (Auchenorrhyncha, Cicadellidae) in three vineyards of the Pisa Province
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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
First remarks on the leafhopper population in a vine-growing area of South-Western Sicily.
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Exploring the role of vibrational cues in a parasitoid-host interaction
No full textThe green peach aphid, Myzus persicae Sulzer (Aphididae, Hemiptera), is a major agricultural pest worldwide, and an efficient vector of several plant viruses, whose control still majorly relies on pesticides. However, the need to reduce pesticide use, given their side effects on non-target organisms and human health, and their inefficacy for containing the spread of aphid-borne viruses, call for research on alternative tools for pest control, such as biological control. Aphidius colemani Viereck (Braconidae, Hymenoptera) is a parasitoid that is commonly used as a biological control agent of M. persicae, but little is known about the behavioral interaction with its host.
The potentiality of Biotremology for pest control has already been highlighted by several studies. However, the role of substrate-borne vibrations in inter- and intra-specific communication in some insect taxa, including aphids and parasitoids, has never been addressed, and further studies may pave the way for the sustainable control of species currently representing major threats for food safety and security.
Therefore, the aim of this study is to characterize the role of substrate-borne vibrations in: i) the inter-specific communication between M. persicae and its parasitoid A. colemani; ii) the intra-specific communication between an “attacked” aphid and its conspecifics. Thereafter, the impact of previously recorded vibrational cues or signals on the aphid feeding behavior will be assessed using the Electrical Penetration Graph (EPG) technique, with a particular focus on the patterns conducive to viruses’ acquisition and inoculation.
Two are the major outcomes expected from the present study: i) insights into the role of substrate-borne vibrations in aphids intra-specific communication and parasitoid foraging behavior; ii) a proof of concept of the applicability of semiophysicals as an alternative to pesticides for aphids and aphid-borne viruses control
Potential use of vibrational signals to manage the Brown Marmorated Stink Bug, Halyomorpha halys, a new invasive agricultural pest
No full textThe Brown Marmorated Stink Bug (BMSB), Halyomorpha halys (Hemiptera: Pentatomidae) is a polyphagous insect that can cause severe economic damage on different crops. In Italy this species was first recorded in the region Emilia Romagna in 2012 and in few years it spread in most of the Northern and part of the Central Italian regions. As well as in other stink bugs the mid-short range mating communication is based on the exchange of vibrational signals (duet) between sexes that is the key of pair formation, courtship and copula. During the duet females are stationary and males actively search on the plant. In other pentatomids the directionality of the searching in males, given by female attractive signals, has been demonstrated. We hypothesize that the same principle works also in BMSB and thus it would be possible to use the female calling signal to attract males towards precise source sites (i.e. artificial shakers). If confirmed, this would represent a potential implementation to the traps commonly used for BMSB monitoring, by providing an additional stimulus to enlarge the amount of captured bugs.
To assess whether the female calling signal could be employed to capture males we performed different bioassays with males stimulated with either natural and synthetic vibrational signals, in different scenarios (i.e., net cages, round arenas, potted plants). Vibrational signals were recorded with laser vibrometer and a video analysis software was used to study the behavioural responses.
Our experiments demonstrated the attractive effect of the female signal in all performed tests. On average, more than 50% of the tested males were attracted to vibrating sources. In addition, we also found a significant increase of walking speed, walked distance and time spent in stimulated areas. These results show promise for developing more efficient trapping techniques against H. halys in both agricultural and urban environments
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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