1,721,021 research outputs found
Lotta alla mosca delle olive in olivicoltura integrata e biologica
Full text linkBactrocera oleae, fitofago chiave dell’agroecosistema olivo, è presente in Italia in tutti gli areali interessati dalla coltura, tranne in alcune aree caratterizzate da maggiore altitudine dove il fattore termico non consente lo sviluppo della specie. Il dittero è fortemente legato alle temperature che del resto condizionano anche la fenologia dell’olivo; in effetti il numero di generazioni che la mosca può completare nell’anno varia da 1 fino a 4-5 in zone con temperature medie annue elevate (zone costiere e/o meridionali). La pericolosità della specie è pertanto legata al numero di generazioni e all’andamento climatico che, a seconda dell’annata e della zona, possono variare sensibilmente condizionando la densità di popolazione e quindi il grado di dannosità potenziale del fitofago. Recenti ricerche sul comportamento e sulla biologia del tefritide hanno messo in evidenza come il fitofago, nel tempo, abbia contratto con i batteri una simbiosi mutualistica che permette al dittero di aumentare il proprio potenziale biotico. Nel presente articolo, dopo un breve excursus sulla biologia e sui danni causati dal fitofago, viene fatto il quadro delle attuali strategie di lotta ammesse nei protocolli dell’olivicoltura integrata e biologica.The control of the olive fruit fly in integrated and organic olive crops. Bactrocera oleae (Rossi) is the key pest of the olive agroecosystem; it is distributed in all Italian olive crops, except in some areas at higher altitude where low temperatures do not allow the development of the fly. The olive fruit fly development is strictly affected by temperature. It can complete from one up to five generations per year in areas with high annual average temperature (coastal and/ or southern areas). The harmfulness of the species is related to the number of generations and weather conditions which may fluctuate considerably year by year, region by region. Recent researches on behavior and natural history of the tephritid fly have pointed out that it has developed a mutualistic symbiosis with bacteria which allows an increase of its growth rate. In this article authors present control strategies permitted in integrated and organic olive crops.
The currently widespread early harvesting and timely milling reduce the harmful influence of late olive fruit fly infestations; together with mass trapping and with repellent/ oviposition deterrent sprays by copper products and clays, these practices allow an increasingly sustainable effective
control of the olive fruit fl
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Asobara tabida (Nees, 1834) (Hymenoptera Braconidae): prima segnalazione per l’Italia di questa specie a diffusione mondiale
No full textGli esemplari sono stati raccolti per la prima volta in Nord Italia, nella Provincia di trento, utilizzando trappole di plastica a caduta, provviste di fori multipli sulle pareti laterali, innescate con aceto di mele come attrattivo (Cini et al. 2012). Le trappole sono state collocate entro la superficie di un appezzamento per la coltivazione ad uso commerciale di mirtillo, Vaccinium corymbosum L., per valutare la densità di popolazione di Drosophila suzukii Matsumura (Diptera: Drosophilidae). A. tabida è un endoparassitoide, koinobionte, solitario, infeudato a molte specie del genere Drosophila spp. di cui la più nota è D. melanogaster (Vet et al. 1984). Questa
specie, estremamente invasiva, è originaria del sud-est asiatico e negli ultimi anni si è diffusa anche nei territori più occidentali. Nonostante la presenza di questo Braconide sia ampiamente documentata in molte regioni europee, nessun dato, ad oggi, era riportato riguardante la sua presenza in Italia (van Achteberg, 2004; Stoch, 2003-2004). La presenza di A. tabida in Italia, in simpatria con quella di D. suzukii potrebbe indicare un suo ruolo come agente di controllo biologico nei confronti di D. suzukii, che è diventata rapidamente un fitofago di estrema rilevanza economica
in numerosi agroecosistemi frutticoli europei (Cini et al. 2012). Una tale considerazione è supportata da ritrovamenti
di adulti A. tabida sfarfallati in Giappone da pupe di D. suzukii (Mitsui et al. 2007). Recenti esperimenti in condizioni di laboratorio non confermano però questa evidenza (Chabert et al. 2012
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