1,720,960 research outputs found
Influence of sustainable control methods on selected life-history parameters of Planococcus ficus (Hemiptera: Pseudococcidae)
Full text linkPlanococcus ficusis a key pest in the most important grape-growing regions. Its effective chemical control is difficult to achieve owing to its biotic potential and concealed habit. In addition, insecticide applications represent a threat for environment and human health. In this PhD thesis, alternative control techniques to reduceP. ficuspopulations were evaluated. Specifically, the effects of different cover crop management systems as well as of increasing nitrogen fertilization regimes on the life-history parameters of the mealybug were investigated in a commercial vineyard and in a screenhouse, respectively. Moreover, laboratory and field trials were carried out to determine the influence of delayed mating and mating disruption on biological and demographic parameters ofP. ficus. Finally, the potential of the parasitoid Leptomastix dactylopii as a biological control agent against the vine mealybug was evaluated under laboratory conditions. The results obtained show that both ground covers and nitrogen fertilization affect developmental and reproductive parameters of the mealybug. Mating disruption reduced and delayed matings, whereasL. dactylopii successfully developed onP. ficusand showed a performance comparable to that of its preferred host, Planococcus citri (Risso). The results indicate that accurate cultural practices and environmentally friendly control methods may effectively integrate the conventional chemical control againstP. ficus
Comparative development and reproduction of<i>Planococcus ficus</i>and<i>Planococcus citri</i>(Hemiptera: Pseudococcidae) on grapevine under field conditions
No full textMealybugs are major pests in grape-growing areas worldwide, causing direct and indirect crop damage. The vine mealybug Planococcus ficus (Signoret) is a key pest in most of grape-producing countries, whereas the citrus mealybug Planococcus citri (Risso) is reported as being destructive in Brazilian and Spanish vineyards. We examined the adaptation of the citrus mealybug to grapevine by investigating its development, reproduction and life-history parameters under Mediterranean field conditions in comparison with those of P. ficus. Both mealybug species developed and reproduced successfully on grapevine. However, P. ficus showed a shorter development time, larger female body size, and higher fecundity, fertility and survival than P. citri. The life-history parameters further highlighted the different growth potential of vine and citrus mealybug populations because P. ficus exhibited a net reproductive rate and an intrinsic rate of increase two- to four-fold higher than that of P. citri. Furthermore, the vine mealybug population doubled its number in approximately half time with respect to the citrus mealybug. Overall, the results of the present study show a better development and reproductive performance and a higher population growth potential of P. ficus compared with P. citri, indicating a higher capacity of the vine mealybug to develop on grapevine in Mediterranean vineyards
Effects of vineyard floor cover crops on grapevine vigor, yield, and fruit quality, and the development of the vine mealybug under a Mediterranean climate
Full text linkThe influence of complete cover cropping (inter- and intra-row) on grapevine growth, yield and must quality was evaluated in a three-year field trial in a commercial vineyard in northwestern Sardinia (Italy). Effects on developmental and reproductive parameters of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), were also investigated. The cover crop treatments were: natural covering, legume mixture, grass mixture, and conventional soil tillage, which was included as the reference treatment. Relative to soil tillage, cover crops reduced grape production by modifying yield components in different ways: legume mixture reduced the cluster weight, whereas grass mixture led to a lower number of clusters per vine coupled with a lower cluster weight. Cover crops also altered the must qualities relative to soil tillage. Grass mixture increased the content of sugar, anthocyanins and polyphenols, whereas legume mixture and natural covering reduced total polyphenols and anthocyanin content, respectively. All the P. ficus biological parameters examined were affected by the floor management practices. Mealybugs reared on grapevines subjected to soil tillage and legume covering showed a faster development time and higher survival, fecundity and fertility than those developed on natural covering and grass plots. The vine mealybug showed a higher performance on grapevines with a higher nitrogen content and vigor. Effects of cover crop treatments appear to be mediated through nutrient availability and content in grape plants. Consequently, utilizing competitive cover crops, while reducing yields, would improve must quality and reduce pest development
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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