1,720,956 research outputs found
Bio-etologia di Tribolium confusum: ruolo dei composti volatili emessi in presenza di competizione intra- ed inter-specifica
No full textRepellence and acute toxicity of a nano-emulsion of sweet orange essential oil toward two major stored grain insect pests
No full textControl strategies in stored-product facilities mainly rely on synthetic pesticides. The development of new environmentally friendly alternatives, such as essential oils (EOs), is a key issue. The aim of this research was to develop a stable nano-emulsion containing a high amount of sweet orange (Citrus sinensis) EO and to evaluate its insecticidal activity against Tribolium confusum du Val (Coloptera: Tenebrionidae) and Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae). The experimental nano-emulsion showed a low surface charge (ζ slightly higher than −30 mV) and a droplet size within the sub-micrometre range (131.37 nm ± 0.29), maintained also after 1 year of storage. The EO nano-emulsion presented good repellence toward both adult insects, which lasted until 24 h of exposure at the highest dosages. Furthermore, the developed nano-formulation showed acute toxicity against both insects when tested as fumigant and cold aerosol. In fumigation trials, adults of C. ferrugineus were more susceptible than T. confusum adults. Moreover, the insecticidal activity of cold aerosol was 5 and 7-fold higher than fumigation against both C. ferrugineus and T. confusum, respectively. The EO-nano-emulsion was effective in controlling and repelling the target pests. Cold aerosol treatments with EO nano-formulations is a promising alternative method for the sanitation of production areas, warehouses, and machineries
Olive fruit volatiles route intraspecific interactions and chemotaxis in Bactrocera oleae (Rossi) (Diptera: Tephritidae) females
No full textPlant nutritional quality and chemical characteristics may affect the fitness of phytophagous insects. Here, the olfactory preferences of Bactrocera oleae (Rossi) females toward olives with different maturation and infestation status were evaluated in three cultivars: Ottobratica, Roggianella and Sinopolese. Volatile profiles from olives were identified by SPME/GC-MS. Choice tests were performed to determine the responses of B. oleae adult females toward fruits and pure chemicals linked to infestation degree. Cultivar was the main source of variability explaining the differences recorded in volatile emissions. Moreover, three VOCs [β-myrcene, limonene and (E)-β-ocimene] were associated to infestation status across all olive varieties. In choice-tests, B. oleae females always preferred the olfactory cues from low-infested over high-infested fruits. Therefore, choice-tests using synthetic VOCs, emitted in greater amount by high-infested fruit, were arranged in order to identify putative B. oleae kairomones. While females were indifferent to β-myrcene, the highest dosages of limonene and (E)-β-ocimene were unfavoured by the tested flies, which preferentially moved toward the empty arm of the Y-tube. Furthermore, females preferred the lowest concentration of β-ocimene compared to the highest one. These results supported our hypothesis that fruit VOCs may serve as kairomones for female flies
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
Field efficacy of two organic acids against Varroa destructor
No full textThe parasitization of honeybees by Varroa destructor represents a serious limiting factor for beekeeping. The past and current widespread use of synthetic acaricides, such as fluvalinate and coumaphos, results in the onset of pest resistance, therefore research efforts focused on the use of alternative solutions to control the population of this parasitic mite. In the present study, the efficacy of two formulates containing Oxalic Acid (OA) or Formic Acid (FA) was evaluated in real field conditions. Our results demonstrated the effectiveness of the OA formulate in controlling more than 90% of V. destructor phoretic population. On the other hand, FA shown an efficacy of 60% on phoretic mites. A similar pattern was highlighted on brood and adult bees’ infestation. The OA formulate showed a proper efficacy, highlighting its potential as alternative to chemical substances in holding the increase of V. destructor during a late summer treatment
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