393 research outputs found
Biology and ecology of Apanteles taragamae, a larval parasitoid of the cowpea pod borer Maruca vitrata
Maruca vitrata Fabricius is a key insect pest of cowpea in West Africa. Larvae of this moth can cause up to 80% of yield losses. The first classical biological control programme against M. vitrata started in 2005 with the introduction of Apanteles taragamae Viereck from Taiwan into Benin by the International Institute of Tropical Agriculture (IITA), Benin station.Thorough knowledge on the bioecology of A. taragamae is a prerequisite for implementing such programme. The work described in the present thesis evaluated the biological potential of this larval parasitoid to fill to the gap of information on its biology and ecology. Special emphasis was put on the main factors that determine the effectiveness/suitablility of biological control candidates, such as reproductive capacity, functional response, climatic adaptability, host foraging capacity, and non-target effects. The results revealed that two-day-old larvae were the most suitable host age, giving the highest percentage parasitism, lifetime fecundity and proportion of females. Larvae older than three days were not successfully parasitized. The percentage parasitism of two-day-old larvae was positively correlated with host density, indicating a good functional response of A. taragamae. Between 20 and 30 °C, the curve that described the relationship between the intrinsic rate of natural increase and the temperature for A. taragamae was above that of M. vitrata, suggesting that the parasitoid can faster build up its population than its host. The parasitoid showed its ability to use volatiles produced by cowpea flowers and host caterpillars when foraging. A host plant odour experience enhanced the capacity of the parasitoid to find uninfested flowers. The growth of non-parasitized or A. taragamae-parasitized larvae was slower and with reduced proportion of female wasps on some host plants compared to those reared on artificial diet. With regard to the non-target effects, the physiological host range and competitive ability of A. taragamae were assessed. None of the following lepidopteran species, Eldana saccharinaWalker, Chilo partellus (Swinhoe), Mussidia nigrivenella Ragonot, Cryptophlebia leucotreta (Meyrick), Sylepta derogata FabriciusandCorcyra cephalonica Stainto,was successfully parasitized by A. taragamae, suggesting its specificity for M. vitrata in Benin. In no-choice competition with the egg-larval parasitoid Phanerotoma leucobasis, A. taragamae outcompeted the latter. All the above attributes suggest that A. taragamae should be a suitable biocontrol agent against M. vitrata. A cage release strategy involved the host plant Sesbania cannabina, which was artificially infested with M. vitrata, and inoculated with adults of A. taragamae. The parasitoid was released in seven selected locations in Benin but the first recovery studies did not yet yield any information on its establishment after the first generation. </p
How I Finished My Dissertation
This session is for everyone contemplating, preparing for, working on, or in the process of finishing their dissertation. Get the play-by-play of how spring 2020 University of Northern Colorado graduate Dannon Cox finished his dissertation and earned his Ph.D. in Sport Pedagogy. Learn how to avoid the common pitfalls that delay many students in their dissertation process and embrace moving purposefully towards the finish line. Dannon offers advice from the trenches to assist doctoral students in removing or bypassing the obstacles that often plague students in the dissertation process
Implementing Digital Media as a Pedagogical Tool in University Physical Activity Courses
Technological advancements have influenced the way we teach, learn, and communicate in education. Higher educational institutions must continually adapt to emerging technologies by implementing a variety of technologies such as photographs, audio, video, and an endless array of online platforms. Specifically, university physical activity programs, which have existed in higher educational institutions for over a century, are encouraged to incorporate digital media as a means to effectively and efficiently communicate a variety of content areas (Cardinal, 2017; Casey, Goodyear, & Armour, 2017; Tiernan, 2015). The purpose of this case study was to explore the implementation of digital media as a pedagogical tool within physical activity courses (PACs). Eight participants shared their lived experiences as instructors of record for PACs throughout the fall 2019 semester. Results showed the need for digital resources both for the instructor as well as students, the value of digital media as a social connection tool, and the need to use Canvas, video, and audio as pedagogical tools. Professional development opportunities are necessary for PAC instructors to effectively and efficiently implement digital media as a pedagogical tool
Efficacité et productivité des banques de la zone UEMOA dans un contexte de réformes financières. Une application de la méthode DEA (Banks efficiency and productivity in the WAEMU in a context of financial reforms : an application of the DEA method)
L’objectif de cette étude est d’une part de mesurer les effets des réformes financières sur l’efficacité et la productivité des banques de la zone UEMOA sur la période de 1996 à 2006 et, d’autre part, de faire ressortir les principaux déterminants managériaux de l’efficacité de ces banques. L’estimation des scores de productivité et d’efficacité est effectuée au moyen de l’analyse de l’enveloppement des données (DEA). Les résultats montrent premièrement que les inefficiences techniques pures dominent les inefficiences d’échelle au niveau de tous les pays la zone excepté le Sénégal. Ainsi, l’inefficience relève plus d’une sous-utilisation des inputs que de rendements d’échelle inappropriés. Deuxièmement, la productivité globale des facteurs a connu une amélioration due essentiellement à la variation positive des progrès technologiques au détriment de l’efficacité technique sur toute la période de l’étude. Ceci laisse penser que les réformes financières n’ont pas permis aux banques de la zone d’améliorer leur efficacité technique. L’évolution de leur productivité est avant tout expliquée par les progrès technologiques existants dans le secteur bancaire de l’espace UEMOA. Troisièmement, les banques de petite taille de la zone UEMOA font plus d’efforts pour réduire la consommation des inputs que celles de grande taille. Par ailleurs, l’efficience d’échelle augmente pour ensuite descendre plus bas qu’à son niveau initial. Cette observation révèle l’existence d’une taille optimale au-delà de laquelle les banques subiraient des déséconomies d’échelle. Quatrièmement, les banques domestiques privées ont un léger avantage en termes d’efficience technique globale et d’efficacité d’échelle sur les banques étrangères tandis que les banques d’Etat ont enregistré les plus faibles scores en termes d’efficacité et de productivité. L’analyse des déterminants des scores d’efficacité montre que l’origine de la propriété, la taille des banques et l’étendue du réseau bancaire ne constituent guère des facteurs déterminants de l’efficacité des banques, du moins pour ce qui concerne les pays de l’UEMOA. En revanche, l’efficacité est influencée par le ratio de capitalisation des banques de l’Union. Enfin, la structure du portefeuille d’actifs des banques et la part des dépôts dans le total bilan sont des variables qui se sont avérées déterminantes aussi bien de l’efficacité technique globale que de l’efficacité technique pure. The purpose of this study is firstly to measure the effects of financial reforms in banks productivity and efficiency in the WAEMU area during the 1996-2006 period, and secondly, to draw the mains managerial determinants of banks efficiency. The productivity and efficiency scores are estimated through the Data Envelopment Analysis (DEA). Our empirical results show firstly that pure technical inefficiencies are higher than scale inefficiencies in all the countries of the area except for Senegal. Thus, the inefficiency stems rather from an under-use of inputs than from an inappropriate return to scale. Secondly, we notice a growth of the global productivity factors which is essentially due to the positive variation of technological progress. Consequently, financial reforms did not permit to banks to increase their technical efficiency. Thirdly, small banks make more efforts to reduce their inputs consumption than great banks. One the other hand, scale efficiency at first increases to decrease then below its initial level. This observation means that there is an optimal size beyond which banks would undergo diseconomies of scale. Fourthly, private domestic-owned banks have a slight advantage on foreign banks in terms of global technical efficiency and scale efficiency while State-owned banks recorded the weakest efficiency and productivity scores. We furthermore conclude that the ownership’s origin, the size of banks and the breadth of the financial network are not much determinant factors of banks efficiency, at least in the WAEMU countries. However, the efficiency is influenced by the capitalization’s ratio of the banks of the Union. Finally, the structure of the banks' portfolio of assets and the proportion of their deposits in the total balance are revealed to be determinants of global as well as pure technical efficiency.banks, efficiency, productivity, data envelopment analysis, financial reforms
Synthesis of unsymmetrical pendant-armed and phosphonic acid-pendant-armed cross-bridged tetraazamacrocycles
The synthesis of a variety of cross-bridged tetraazamacrocycles bearing phosphonate pendant arms and their corresponding phosphonic acid derivatives as well as their Cu(II) complexes are presented. The half-life of decomplexation of Cu(II)·51 in 5M HCl at 90°C was found to be 3.8 hours. Ligand 51 showed faster complexation kinetics relative to known cross-bridged tetraazamacrocycles bearing ionizable pendant arms. The biodistribution of 64Cu(II)·51 was studied in male rats and indicated an improved blood and liver clearance and higher bone retention of 64Cu(II)·51 relative to 64Cu(II)·10.*.
The formation of a single pendant-armed cross-bridged cyclam is presented through an unusual single alkylation of cross-bridged cyclam. Several experiments were implemented to probe the origin of the selectivity of the reaction including computational studies, 1D 1H NMR and 2D NMR experiments. Monoamide ligand 64 was used as a springboard for the formation of several unsymmetrical pendant-armed cross-bridged cyclams.*.
Attempts were made toward the synthesis of two potential bifunctional chelators for radiopharmaceuticals, each bearing only one phosphonic acid pendant arm and one free carboxylate for conjugation to somatostatin analogues.*
Functional response and life history parameters of Apanteles taragamae, a larval parasitoid of Maruca vitrata
The legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a serious pest of cowpea in West-Africa. The parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) that originates from Taiwan is a potential candidate for biological control of M. vitrata. We investigated under laboratory conditions the functional response of the parasitoid by offering each experienced female 10, 20, 30 and 40 larvae of M. vitrata. We studied the influence of different host larval ages on the development, longevity, sex ratio, lifetime fecundity and parasitization rate of the wasp. In a comparative study, we also investigated the life history of A. taragamae and M. vitrata at different temperatures in the range of 20–30C. The parasitoid successfully parasitized two- and three-day-old host larvae (first and second instars). Younger larvae (one-day-old) were parasitized to a lesser extent, and only males developed in them. Older larvae were not parasitized, partly because of defensive host behaviour. The success of arasitization was positively correlated with the density of two-day-old M. vitrata larvae. Parasitoid developmental time and longevity decreased with increasing temperature. The intrinsic rate of population increase (rm) exhibited an optimum curve with a maximum at 24–28C. For the host M. vitrata, rm was maximal at temperatures of 26–30C. The data are discussed in the context of the potential of A. taragamae for biological control of M. vitrata
Responsabilité sociale d’entreprises et banques africaines de développement : analyse théorique et étude empirique
Responsabilité sociale d'entreprise et banque de développement africaines : analyse théorique et étude empirique
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