1,720,987 research outputs found
Experimental study on the utilisation of substitute food resources by parasitic wasps and syrphid flies attacking the rosy apple aphid Dysaphis plantaginea (Passerini) (Homoptera :Aphididae)
No full textThe rosy apple aphid Dysaphis plantaginea (Passerini) (Homoptera: Aphididae) is the most serious pest apple aphid in view of the scale of damages inflicted to the fruits by a small number of individuals. Although numerous natural enemies have been associated with D. plantaginea, they are unable to halt infestations soon enough in most commercial apple orchards obliging fruit growers to control it chemically to prevent severe economic losses. In order to reinforce the contribution of indigenous aphidophaga in regulating rosy apple aphids, the use of insectary plants selected to support two groups of specialist aphid antagonists, notably aphid parasitoids and aphidophagous monovoltine syrphids, was investigated. 1. A first step consisted in selecting appropriate plant species. The rowan tree Sorbus aucuparia L. and the common elder Sambucus nigra L. were selected for their ability to support substitute aphids for the rosy apple aphid parasitoid E. persicae Froggatt (Hymenoptera: Braconidae, Aphidiinae) and monovotine syrphids (Diptera: Syrphidae) respectively. 2. Next, trials were conducted to induce substitute aphid infestations on their host plants by introducing eggs of Dysaphis sorbi Kaltenbach on rowan and small colonies of Aphis sambuci L. on elder. The resulting aphid populations which developed on their respective host plants in spring proved to be exploited by the natural enemies expected, i.e. E. persicae and monovoltine syrphids of the genus Epistrophe. Besides, diapause mummies of E. persicae and diapausing last-instar Epistrophe larvac were recorded on rowan and in the elder litter respectively, indicating the successful settlement of the antagonists in the orchard environment. A complementary investigation devoted to syrphid adults indicated that females of all species recorded ovipositing on the eider shrubs, including Epistrophe spp. had consumed a large majority of apple pollen grains as a protein source required for egg maturation. 3. To comfort our choice in the two groups of aphidophaga considered, a study dedicated to their respective phenology versus the one of D. plantaginea showed that they could both potentially halt rosy apple aphid infestations by attacking the aphids while the latter still occupied the primary, fundatrix-induced rosette leaf colonies, i.e. a critical moment in rosy apple aphid control. 4. Finally, marking methods were tested to label E. persicae internally and the egg load of gravid syrphids. These trials were intended to pave the way towards future mark-release-recapture experiments aimed to evaluate the antagonists’ activity range and thus strategically position the insectary plants for optimal aphid biological control in the whole orchard. The first step of new approach in the biological control of D. plantaginea has been set with this study. Its originality lies in the induction of economically indifferent aphid infestations on selected plants introduced in the orchard to encourage well-targeted groups of specialist aphid antagonists. Further trials are still needed to validate the field efficacy of the insectary plant systems developed and evaluate their possible integration within the whole array of pest management tools in both organic and integrated apple production.Doctorat en sciences, Spécialisation biologie animaleinfo:eu-repo/semantics/nonPublishe
Mass trapping Drosophila suzukii : context-dependency of olfactory attraction and requirements for implementation
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Cibler l’oncoprotéine E7 vers la voie de présentation du complexe majeur d’histocompatibilité de classe II: une piste vers un nouveau vaccin contre les lésions (pré)cancéreuses du col de l’utérus induites par le papillomavirus humain de type 16 (HPV-16)
No full textLes papillomavirus humains (HPV) oncogènes sont les agents étiologiques des cancers du col utérin. S’il est établi que 30 à 60% des femmes sont infectées par un HPV oncogène, seul 1% des cas d’infection évoluera vers un cancer invasif, les autres se résolvant spontanément, ce qui autorise à penser qu’une vaccination adéquate pourrait permettre de maîtriser, voire de guérir, les lésions (pré)cancéreuses induites par ces virus. A ce titre, les cibles préférentielles sont les protéines virales E6 et E7. En effet, non seulement ces protéines sont à la base du processus de transformation cellulaire et leur présence est requise pour le maintien du phénotype transformé mais, de plus, elles contiennent des épitopes reconnus par les lymphocytes T auxiliaires et cytotoxiques. Nous avons choisi d’orienter nos recherches sur le virus HPV de type 16 car son incidence est majeure. De même, le taux élevé d’expression de la protéine E7 dans les tumeurs nous a conduit à la choisir comme cible. Notre travail a consisté en la construction de vecteurs plasmidiques codant pour des protéines HPV-16 E7 native ou de fusion. Les fusions ont été réalisées afin de modifier la nature de la protéine E7 afin de la cibler vers les voies de présentation en association avec les molécules du complexe majeur d’histocompatibilité de classe I ou de classe II (MHC-I ou MHC-II). Nous avons étudié et comparé les réponses induites par nos vecteurs afin de déterminer le vecteur le plus efficace. Nous avons ensuite étudié le mécanisme d’action de ce vecteur afin de déterminer les points clés de l’élaboration d’une réponse immune anti-HPV-16 E7. Nous avons ainsi déterminé que cibler la protéine HPV-16 E7 vers la voie du MHC-I (protéines de fusion avec l’ubiquitine; Ub) n’augmentait pas son immunogénicité. A l’inverse, le ciblage de cet antigène vers la voie du MHC-II (protéine de fusion avec la chaîne invariante; Ii) permet à une majorité de souris C57BL/6 de résister à l’injection d’une dose léthale de cellules tumorales syngéniques E7-positives. Nous avons également montré que l’injection du vecteur ciblant E7 vers la voie du MHC-II permet l’élimination de cellules présentant un épitope classe I H-2Db. Cette réponse est médiée par des lymphocytes T CD8+. Nous avons également montré que, si la présence des cellules T CD4+ n’est pas nécessaire pour l’élimination proprement dite de cellules E7-positives, la génération des effecteurs de cette élimination requiert la présence de lymphocytes T CD4+. Nos investigations nous ont permis d’émettre l’hypothèse de l’apparition d’une réponse par transfection directe d’APC et présentation d’épitopes par les voies classiques sur MHC-I et –II, le phénomène de cross-présentation semblant ne pas être impliqué dans la genèse de la réponse. Nos résultats suggèrent donc que c’est l’instabilité de E7 qui fait de cet antigène abondamment synthétisé un piètre inducteur de réponses cytotoxiques. En effet, l’ubiquitination N-terminale de E7 provoque sa dégradation rapide et pourrait empêcher sa sécrétion. Lorsque l’on tient compte de la nécessité de l’activation de cellules T auxiliaires dans l’élaboration des réponses anti-E7 enregistrées, cette dégradation pourrait permettre à E7 de ne pas être présenté sur MHC-II et donc de ne pas générer les cellules CD4+ requises pour la génération des cellules CD8+. Finalement, nous avons montré que cibler une protéine E7 délétée de son motif oncogénique majeur vers la voie du MHC-II menait à l’apparition de réponses cytotoxiques anti-E7 efficaces.Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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