1,720,962 research outputs found
Metodologia per l’individuazione di piante plus di Q.suber L. e la caratterizzazione merceologica del sughero
No full textLong-term monitoring and microbiological control programs against lepidopteran defoliators in Sardinian cork oak forests (Italy)
Full text linkThe gypsy moth, Lymantria dispar (L.), and the tent caterpillar, Malacosoma neustrium (L.), are the main cork oak, Quercus suber L., pests in the Mediterranean area and cause complete defoliation in large forest districts. In order to control infestations, large scale aerial applications of insecticides based on Bacillus thuringiensis subsp. kurstaki (Btk) have been carried out in Sardinia (Italy) since 2001. This paper evaluated the frequency of outbreaks in forest districts with varying homogeneity of land use, forest areas annually exposed to defoliation and the effectiveness of control programs based on Btk insecticide applications. The volume of areas annually exposed to defoliation depends on forest homogeneity, as infestations are more frequent in cork oak areas with a lower than 25% canopy cover rate. The microbiological control programme efficiently protected cork oaks from lepidopteran defoliators and caused an overall annual mean mortality of over 60%, with maximum rates of 89.9 and 98.0% for L. dispar and M. neustrium, respectively. To date, approximately 180,000 hectares of cork oak forests have been protected by spraying Btk-based insecticides
Comparative efficacy trials with two different Bacillus thuringiensis serovar kurstaki strains against gypsy moth in mediterranean cork oak forests
No full textThe efficacy of two formulations (Foray® 76B AVIO and Rapax® AS AIR) containing different Bacillus thuringiensis kurstaki (Btk) strains (ABTS-351 and EG-2348, respectively) was evaluated against Lymantria dispar larval populations in cork oak forests in Sardinia (Italy), in 2018 and 2019. The experimental design involved the following treatments: (I) untreated control; (II) Foray® 76B at the dose of 2.0 L/ha; (III) Foray® 76B at the dose of 2.5 L/ha; (IV) Rapax® AS AIR at the dose of 2.0 L/ha. Aerial applications were carried out using a helicopter equipped with four electronic rotary atomizers adjusted to sprinkle 160 micron-sized drops. Btk efficacy was evaluated by assessing the larval density reduction 7, 14, and 21 days after the application in each experimental plot in comparison with an untreated check. In addition to field surveys, the mortality of second and third instar larval samples, randomly collected from each plot after treatment and fed with foliage from the same plot, was determined in the laboratory. All Btk treatments were similarly effective, and no differences in larval density reduction among Btk strains and doses were found in either year. Twenty-one days after application, the average larval density reduction in the field was approximately 70% in all treated plots in 2018, whereas in 2019 it reached 80% only in areas treated with Foray 76B at 2.5 L/ha. Laboratory observations showed that all Btk-based products were effective against gypsy moth larvae, with significant differences in mortality between untreated control and the different Btk treatments. Our results shed light on the possibility of alternating different Btk strains for resistance management purposes and of applying lower doses than labeled, in order to achieve cost savings for product shipment and distribution and to reduce the environmental impact
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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