1,721,019 research outputs found
Susceptibility to BT of wild lepidopteran species in Nature Reserve in Sicily
No full textA wide range of crop plants and trees have been transformed with genes derived from the soil bacterium Bacillus thuringiensis (Bt) to express insecticidal proteins (insect-resistant Bt plants). Whereas the adoption of Bt plants constitutes one of the most common uses of transgenic plants in agriculture, the environmental benefits and risks remain an issue. To preserve the natural reserve and their fauna UE proposed that in future the Member State specify a minimum separation distance of metres between fields of GM plants and nature reserves or to forbid cultivation of GM plant in particular area based on scientific data. Natural reserve in Sicily have many endemism and rare species so next steps also in Italy should consider this before adaptation of GM crops. One first step is to obtain a listing of lepidopteran species that feed on these crops and their wild relatives, and to determine the host range of the larvae. Second to assess Bt toxin susceptibility for these lepidopterans. Only few species of Lepidoptera have been tested for susceptibility; and the literature suggests that generalizations about susceptibility among taxa are difficult due to the variability within families. However a similar approach could be interesting also for Bt as commercial product. We report the data on the susceptibility to Cry IAb and to Bt as spray for some not target lepidopteran species
Susceptibility of Tortrix viridiana L. to Bacillus thuringiensis var. kurstaki at different level of larval development.
No full textRecently out-breaks of the green oak leaf roller Tortrix viridana L. (Lepidoptera,
Tortricidae) were recorded in Natural Reserve in Sicily (Italy) where treatments are generally forbidden. The commercial, social and environmental value of the wood in the forest needs to be preserved and biological control could be applied in particular case. To optimise the permitted
biological treatment, not only in terms of product amount but also for the time of application baseline susceptibility of T. viridiana from the Natural Reserve of Ficuzza (Palermo, Italy) to a
commercial formulation of Bacillus thuringiensis was determined for neonates and 2, 5, 10 and 15 day old larvae. The differences in susceptibility of the different larval development were recorded.
For neonates the calculated DL50 was 0.63 μg/ml, while after five days it was 10.01 μg/ml. The same doses had little effect on the older larvae, showing a clear decrease in susceptibility with age and larval growth. A relationship was also found between susceptibility and body length. The
implications of these data in controlling this pest in the natural reserve are discussed
From non-target risk assessment to Bt resistance management: the example of Bt Brassica sp. and Pieridae
No full textInsecticidal toxins produced by Bacillus thuringiensis (Bt) have been widely used in plant protection in two different ways: 1) by spraying bacterial Bt formulations, 2) by expressing their gene encoding in planta. In the second strategy, only the transgenic plants themselves are protected but insect- resistant plants could spread into natural habitats and/or the gene could be fixed in alternative hosts. It is necessary to estimate the magnitude of the possible effects on naturally occurring herbivorous insects but also on the target species, especially when they have several alternative hosts, as in the case of Pieridae. They are present both in agriculture where they could be considered pests, and non- agricultural habitats, where the larvae feed on several Brassicaceae. Moreover, oilseed rape is known to form feral populations in natural and semi-natural habitats, and that Bt- oilseed rape may out-compete insect-susceptible plants at high herbivore densities. Furthermore, high-density patches of highly damaged wild plants are the most vulnerable to Bt-transgene invasion. To assess the potential risk of Bt resistance in Pieridae, different parameters should be considered. In this contest we thought it worthwhile to study the population density of Pieridae, their fly period compared with the flowering period of potential Bt crops and relative wild species and its hosts preferences Moreover we report data on susceptibility to commercial Bt and to CryIAb toxin. Such data may both aid the design of further tests of related effects and aid in the assessment of any effects on the population outside the agricultural area
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
Preliminary selection of non-target Lepidoptera species for ecological risk assessment of Bt canola in Sicily
No full textIt is essential to assess the environmental risk that Bt canola resistant to Lepidopteran pests may hold and to study its effect on species assemblages that fulfil a variety of ecosystem functions. Environmental risk assessment can be improved through the use of an ecological model which can be applied to a specific environment, so that local species can be classified functionally and prioritized to identify potential test species. Several other Lepidoptera species are also directly exposed to Bt toxin. In this paper an ecological approach was followed for selection of non-target Lepidoptera species for ecological risk assessment of Bt canola in Sicily, using data collected over a one-year period on Lepidoptera biodiversity on different habitats. Non-target Lepidoptera most likely to be affected were identified and prioritized for future testing and inclusion in risk assessments. Through use of the selection matrix, knowledge gaps were identified for future research and guidance for the design of ecologically realistic experiments
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
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