Nitrogen (N) fertilizer applied in the fall has been shown to increase emissions of N2O a GHG (Nyborg et al. 1997). Applying N fertilizer in the spring is a management technique Saskatchewan grain and oilseed producers can use to reduce N2O emissions. The hypothesis of this thesis is that fall application of N fertilizer is more profitable than spring application. Factors to consider in the timing of fertilizer application include, the level of information available, input cost, input efficiency, and application cost. The key objective of this thesis is to determine the financial impact of switching to spring N application from fall N application. Stochastic variables include fall subsoil moisture, winter precipitation, growing season precipitation, input costs, and output prices. Expected utility theory for two representative farms at two locations is used to determine optimal N fertilizer rates and the value of spring subsoil moisture information and the value of spring output price forecasts. The fixed and variable operating costs are calculated for three seeding systems. The results show that it is optimum for producers to purchase N fertilizer in the fall and apply N fertilizer in the spring. Spring subsoil moisture information, and spring output price forecasts have little value to producers committed to continuous cropping. One pass (seed and fertilize in the spring) seeding systems have lower variable and fixed costs than two pass seeding systems for producers applying large amounts of fertilizer.

Nitrogen (N) fertilizer applied in the fall has been shown to increase emissions of N2O a GHG (Nyborg et al. 1997). Applying N fertilizer in the spring is a management technique Saskatchewan grain and oilseed producers can use to reduce N2O emissions. The hypothesis of this thesis is that fall application of N fertilizer is more profitable than spring application. Factors to consider in the timing of fertilizer application include, the level of information available, input cost, input efficiency, and application cost. The key objective of this thesis is to determine the financial impact of switching to spring N application from fall N application. Stochastic variables include fall subsoil moisture, winter precipitation, growing season precipitation, input costs, and output prices. Expected utility theory for two representative farms at two locations is used to determine optimal N fertilizer rates and the value of spring subsoil moisture information and the value of spring output price forecasts. The fixed and variable operating costs are calculated for three seeding systems. The results show that it is optimum for producers to purchase N fertilizer in the fall and apply N fertilizer in the spring. Spring subsoil moisture information, and spring output price forecasts have little value to producers committed to continuous cropping. One pass (seed and fertilize in the spring) seeding systems have lower variable and fixed costs than two pass seeding systems for producers applying large amounts of fertilizer.

Directional selection is prevalent in nature yet phenotypes tend to remain relatively constant, suggesting a limit to trait evolution. The genetic basis of evolutionary limits in unmanipulated populations, however, is generally not known. Given widespread pleiotropy, opposing selection on a focal trait may arise from the effects of the underlying alleles on other fitness components, generating net stabilizing selection on trait genetic variance and thus limiting evolution. Here, I look for the signature of stabilizing selection for a suite of cuticular hydrocarbons (CHCs) in Drosophila serrata. Despite strong directional sexual selection on CHCs, genetic variance differed between high and low fitness individuals and was greater among the low fitness males for seven of eight CHCs. Univariate tests of a difference in genetic variance were non-significant but have low power. My results implicate stabilizing selection, arising through pleiotropy, in generating a genetic limit to the evolution of CHCs in this species.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

This report evaluate the maintenance policies that been applied within specific industrial company, Taken into considerations all corrective and preventive maintenance costs ,in addition to optimise best preventive maintenance schedule for minimum cost. Dynamate Intralog AB was the surveyed company that been encountered high maintenance cost compatible with less productivity, therefore obtaining maintenance schedule policy for minimum cost was the best solution for their problem, then by calculating their corrective and preventive maintenance cost the optimum time was acquired. Finally, the maintenance schedule approve that organized maintenance based on optimum time enhance the productivity and minimize the company maintenance cost.