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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied mathematics & optimization 31 (1995), S. 1-17 
    ISSN: 1432-0606
    Keywords: Bellman equation ; Hamilton-Jacobi equation ; Quasi-variational inequality ; Viscosity solution ; Unbounded solutions ; Optimal switching ; Optimal control ; State constraints ; Production engineering ; 49C05 ; 49C20 ; 49B10 ; 49A36
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We study a quasi-variational inequality system with unbounded solutions. It represents the Bellman equation associated with an optimal switching control problem with state constraints arising from production engineering. We show that the optimal cost is the unique viscosity solution of the system.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-8248
    Keywords: parasitoids ; breeding conditions ; Raphitelus maculatus ; nourishment ; parasitoides ; conditions d'élevage ; Raphitelus maculatus ; alimentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Raphitelus maculatus Walker est un parasitoide fréquemment associé au scolyte de l'olivier,Phloeotribus scarabaeoides Bernard, qui hiverne dans les branches de l'olivier (Olea europea L.). Dans les conditions contrôlées de laboratoire (22 ± 2°C, 60% H.R. et photopériode 16L∶8.0.),R. maculatus complète son cycle larvaire en 17 jours environ, tandisqueP. scarabaeoides effectue son développement en 48 jours. On a étudié l'effet des conditions d'élevage sur la longévité des adultes et sur la fécondité des femelles et on a observé qu'elles sont très sensibles aux conditions alimentaires. La longévité varie selon la disponibilité en eau et en nourriture entre 2.65 et 14.95 jours chez les ♂♂, entre 5.04 et 15.57 jours chez les ♀♀. La fécondité (nombre moyen d'œufs déposés) varie entre 18.2/♀♀ sans nourriture et 44.5/♀♀ alimentée.
    Notes: Abstract The rearing ofRaphitelus maculatus Walker, which oviposits through the bark onto beetle larvae has been carry out under standard laboratory conditions of 22 ± 2°C, 60% R.H. and photoperiod 16L∶8D. The host (Phloeotribus scarabaeoides Bernard) has been reared by cutting fresh branches of living olive tree on which they overwinter as adults. The effect of several rearing conditions (feeding conditions) on longevity and fecundity has been tested. The time of parasitoid and host development as well as the periods of emergence from the infested cut branches has been determined. It has been noted that both longevity and fecundity are influenced by the feeding conditions, reaching toca. double value when parasitoids were fully fed. Under standard rearing conditionsR. maculatus completes its life cycle in 17–18 days depending on sex, whereasP. scarabaeoides takes about 48 days. Finally 3 emergence periods has been observed from which the 1st is the most important and the 3rd is always the less significantly one, provided that the emerging brood cannot oviposits easier than the parents due to a decrease on host larvae proportion as well as on parasitoid fecundity.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-8248
    Keywords: parasitoid rearing ; Cheiropachus quadrum ; Raphitelus maculatus ; biotic potential ; olive tree beetle ; élevage ; parasitoïde ; Cheiropachus quadrum ; Raphitelus maculatus ; potentialité biologique ; scolyte de l'olivier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Nous avons réalisé l'élevage des principaux parasitoïdes du scolyte de l'olivier,Phloeotribus scarabaeoides (Bernard, 1788) au Sud de l'Espagne:Cheiropachus quandrum (Fabricius, 1787) etRaphitelus maculatus Walker, 1834, en conditions contrôlées de laboratoire (22±2°C, 60±5% H.R. et photopériode 16L.: 8 D.), et nous avons testé différentes densités de population pour en connaître le comportement reproducteur, ce qui est très important pour obtenir un meilleur rendement de l'élevage. Les résultats de l'examen montrent l'existence d'une forte concurrence entre les individus du même sexe; chez la femelle cela implique une réduction de la fécondité, montrant une corrélation potentiellement négative avec la densité de population. Nous avons évalué les potentialités biologiques qui correspondent aux 2 principales espèces de parasitoïdes, avec et sans concurrence des ΦΦ par l'oviposition, et nous avons discuté les rapports entre la colonisation des sites d'infestation du scolyte de l'olivier et ses parasitoïdes.
    Notes: Abstract Under laboratory conditions (22±2°C, 60%±5% H.R.; and 16L.: 8D. photoperiod), the rearing of the 2 main parasitoids ofPhloeotribus scarabaeoides (Bernard, 1788) in Southern Spain:Cheiropachus quadrum (Fabricius, 1787) andRaphitelus maculatus Walker, 1834 (Hym.: Pteromalidae) has been carried out. Several densities of population of the parasitoids have been tested in order to determine their reproductive behaviour, and this is significant if the output of a rearing is to be increased. A great competition among the individuals of the same sex has been observed; in the case of the ΦΦ, a potential negative correlation with the increase of density of population, has been noted. The biotic potential belonging to the 2 principal parasitoids species with and without competition, are calculated, and the aspects concerning the parasitoid colonization of the olive tree beetle infestation spots, are discussed.
    Type of Medium: Electronic Resource
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