1,720,960 research outputs found
Esperienze di gestione del ricamatore Argyrotaenia ljungiana in vigneto con il metodo della confusione sessuale
Full text linkNegli ultimi anni, nei vigneti del Trentino e specialmente in quelli lungo il fiume Adige, è stato osservato un incremento delle popolazioni di Argyrotaenia ljungiana, comunemente nota come eulia dei fruttiferi e della vite. Sono state condotte 4 prove sperimentali al fine di valutare l’efficacia del prodotto per la confusione sessuale Isonet LA plus, un diffusore a riserva di carica che, oltre al feromone specifico di Lobesia botrana e Eupoecilia ambiguella i due fitofagi chiave su vite nel territorio, contiene anche (Z)11-tetradecenyl-14 acetato (Z11- 14:Ac), il componente principale della miscela feromonica naturale di A. ljungiana. L’efficacia di Isonet LA plus nel contenimento dei tre fitofagi è stata comparata con quella del prodotto per la confusione sessuale di riferimento, Isonet L plus, comunemente impiegato già da anni nell’area per il controllo di L. botrana e E. ambiguella soltanto, rilevando l’eventuale inibizione delle catture degli adulti in trappole di monitoraggio, il danno sui frutti, e l’erogazione di fermone mediante analisi gascromatografiche. Le prove hanno evidenziato la buona efficacia di Isonet LA plus, in corso di registrazione, nel contenimento di tutte e tre le speci
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
Uso de vibrações sonoras na interruptção da corte da cigarrinha Scaphoideus titanus: do laboratório para o campo
No full textUse of noise generators to inhibit mating of leafhoppers
Full text linkLeafhoppers (Hemiptera Cicadellidae), notoriously include many important insect pests which use species-specific substrate-borne vibrations as mating signals to estimate identity and to perform location and courtship, after establishing a vibrational duet with the partner.
Scaphoideus titanus is a grapevine pest, vector of the phytoplasma disease “Flavescence dorée”. In this species rival males show complex rivalry behaviour which includes the emission of a specific disturbance noise to interrupt a mating duet of another couple. Our hypothesis was that by playing back the disturbance noise into grapevine plants we would have been able to disrupt the mating behaviour of S. titanus, thus preventing the copulation.
Our experiments of mating disruption started in 2008 and followed 5 steps.
1) Description of the mating behaviour of S. titanus and the vibrational signals associated to the phases preceding the copula (Fig.1).
2) Laboratory tests on pairs placed on a grapevine leaf to demonstrate that mating disruption with vibrational signals was feasible.
3) We tested a system of potted plants inside plastic cages interconnected by iron wires, to simulate a vineyard trellis. Virgin pairs of S. titanus were released into the cages for 18 hrs (4 pm to 10 am) and a first prototype of a vibrational shaker was used to vibrate the wire. As a result more than 90% of pairs remained unmated (in control treatment only 20% of pairs did not mate).
4) We applied vibrational mating disruption to mature plants in an open vineyard. Pairs of virgin males and females were released inside net sleeves including 3-4 grapevine shoots with fully developed 8-12 leaves. Again the disruption signal, generated by a specific device, was continuously applied to plants through the supporting trellis wire for 18 hrs. Results showed that even 10 m away from the source more than 90% of pairs remained unmated, compared to 20% of non-mated pair in controls .
5) We applied the method to test new prototypes of vibrating device that may be effective at longer distances and with different disruption time regimes in order to spare energy consumption. We found that 65% of mating disruption is still achieved at 45m and that at least 18 hrs of disruption are necessary to have 80% of success.
Now our aim is to further optimize the system in order to:
(1) make the device more effective for control of S. titanus and other leafhoppers;
(2) make it an economically sustainable tool for agricultural use;
(3) to set pilot and demo tests in commercial farms starting from 2015
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
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