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A simple illustrative mathematical model for integrating forest pest control decisions with timber management is developed for a hypothetical jack pine forest infested with jack pine budworm. Subject to several assumptions made in the model, optimal quantities and timings of pesticide application and optimal rotation ages of the forest are determined under various sets of parameters such as cost of pesticide, stumpage price, pest population growth rate and age of the forest at the time of pest infestation. The sensitivities of the optimal values to these parameters are examined. In general, the rotation age and hence harvesting schedule is affected under different pest situations, site conditions and economic parameters. In addition, immediate pest control action following noticeable pest infestation in young crops may not always be the most profitable decision, particularly when only one pesticide application is permitted and when net return expected from a crop is low. These findings have implications for effective pest and timber management. Nous avons élaborté un modéle mathématique simple intégrant les décisions de lutte contre les parasites forestiers et la gestion du bois d'oeuvre pour une forit de pins gris hypothétique infestée de tordeuses du pin gris. Nous avons ainsi déterminé les quantités optimales et l'échéancier pour l'épandage de pesticides ainsi que l'âge optimal de rotation de la forêt, compte tenu de divers groupes de parametres (par exemple, coût des pesticides, prix du bois sur pied, taux de croissance et date de l'infestation), en vertu de diverses hypothèses de départ intégrées dans le modèle. Nous avons examiné la sensibilité des valeurs optimales face è ces paramètres. En général, l'âge de rotation et, par ricochet, l'échéancier de la récolte changent en fonction de I'ampleur de I'infestation, de l'état du peupfement et des paramétres économiques. En outre, I'application de mesures immédiates de lutte dès les premiers signes d'une infestation dans les jeunes peuplements risque de ne pas toujours étre la decision la plus profitable, en particulier lorsqu'on ne permet qu'un seul épandange et que le revenu attendu d'une récolte est faible. Ces résultats ont une incidence sur les mesures de lutte antiparasitaire et sur la gestion du bois d'oeuvre.

Biofouling prevention remains a major challenge to the chemists, and researchers around the world who are engaged in the development of antifouling paints that can prevent growth of organisms like barnacles, algae and tubeworms on the submerged structures. Growth of organisms on the surfaces exposed to marine and freshwater environment not only reduces the efficiency of such structures, e.g. reduction of heat transfer etc, but also causes structural damages. In order to prevent the growth of organisms on surfaces of the marine and freshwater environments, coatings containing biocides are generally used. However, use of biocides not only leads to the corrosion of the metallic structures in some cases, but it also inflicts severe damage to the aquatic ecosystem. It is thus necessary to develop anti-biofouling paints that are innocuous to both the environment and the structures. One alternative approach may be incorporation of nanoparticles, and preventing bacterial bio-film formation as well as the attachment of larger organisms. Various nanoparticles of metal and their oxides have been recognized to possess antibacterial properties. The development of such materials is a challenge to both the chemist and the biologist, where effective choice of methods that provide relevant information regarding application of the metal nanoparticles in anti-fouling materials, becomes the central objective. The present article is a short review in the area of nanoparticle doped antifouling paints. In addition, some aspects covering our experimental results on the selected bio-fouling paints with dispersed nanoparticles of ZnO, CuO, Al2O3, MgO, TiO2 and Co3O4. It also discusses the techniques used for the characterization of the nanoparticle-doped materials and methods for the determination of their efficacy against bio-film formation.

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