The MANIMEA $ rm ( underline{MA}nurial underline{NI}trogen underline{M}anagement{:} underline{E}nvironmental underline{A}spects)$ model is a one-dimensional dynamic model that simultaneously simulates nitrogen transformations (volatilization, net mineralization-immobilization, and denitrification), nitrogen transport (runoff and leaching), plant uptake, and adsorption in homogeneous, unsaturated soils. The simulated system is divided into two components: the applied manure layer and the soil. The model describes the transformation processes occurring in both components separately. It is also capable of accounting for both micro and macroporous flows. In addition, the simulation can be done for time steps shorter than 1 day. / The model was developed to be interactive and user-friendly and was constructed on a modular basis using Microsoft FORTRAN PowerStation$ sp circler$ as a compiler. It can be run on an IBM$ sp circler$ or IBM compatible microcomputer with a minimum requirement of a 386 microprocessor with 4 MB RAM. This model was developed as a nitrogen management-oriented model. However, it can also be used to gain further understanding of nitrogen processes for research and teaching purposes. / The accuracy of the stimulation was enhanced by taking into account moisture and temperature variation and distribution in the soil. The SWACROP and the HEAT programs were integrated into the MANIMEA model to generate transient moisture and temperature profiles, respectively. The Numerical Method Of Lines (NMOL) technique, which implements finite difference method, was used to numerically solve the partial differential equations in the model. / Generally, the results generated by the MANIMEA model using the parameters from literature agreed with the results obtained by analytical solutions and from experiments. It was found that the model is highly sensitive to the volatilization and net mineralization rate constants $(K sb{v}$ and $K sb{m}).$ The study showed that the MANIMEA model can be implemented to evaluate nitrogen transformations, transport, and plant uptake for a wide range of climatic and soil conditions and organic type of wastes. Such a tool can contribute to the protection of our environment through a better management of organic nitrogen fertilizer and a better understanding of the nitrogen processes.

No description available.

Background: The amount of parenteral protein to produce nitrogen balance in infants diagnosed with severe heart defects undergoing cardiopulmonary bypass surgery was investigated. Methods: Infants born at ≥36 weeks and ≤ 12 months of age were randomized to one of three parenteral protein intakes, the control group received 1.5 g/kg/d and intervention groups received either, 2.2 or 3.0 g/kg/d of protein, respectively. Timed 24 hour urine collections were obtained for three consecutive days following surgery. Total urinary nitrogen was measured through Kjeldahl analysis. Results: A significant difference was demonstrated between the lowest protein intake level of 1.5 g/kg/d and both 2.2 g/kg/d (p ≤ 0.03) and 3.0 g/kg/d (p ≤ 0.001), on study day 1. Nitrogen balance results were 4.0 ± 52.9 (1.5 g/kg/d), 97.0 ± 96.2 (2.2 g/kg/d) and 149.7 ± 90.9 (3.0 g/kg/d). Conclusion: Protein delivery of 1.5 g/kg/d was insufficient to produce nitrogen balance on post-operative day 1.

No description available.

An experiment was conducted for two years to determine the effect of seeding rate, and nitrogen fertility on the yield and quality of hard red spring wheat (Triticum aestivum L.) in Quebec. The experiment was conducted on a Ste-Rosalie series soil (humic gleysol), in the St-Hyacinthe region, 50 km east of Montreal. The design of the experiment was a split-plot design. The treatments in the main plots were the plant densities while the nitrogen treatments (rate of nitrogen, number and timing of the applications and formulation of fertilizer nitrogen) were applied to the sub-plots. Nitrogen had a significant effect on yields in 1987, but not in 1986. Maximum yield was 6838 kg ha$ sp{-1}$ in 1986 and 3807 kg ha$ sp{-1}$ in 1987. Protein concentration was increased by higher nitrogen rates in both years. The yield and protein concentration were affected by low precipitation in 1987. Applying the nitrogen later in the season increased the protein concentration in both seasons. It also decreased yield in 1987, but this was caused by lack of water in late June and July 1987. Formulation of nitrogen fertilizer did not have an effect on yield and protein content of the crop.

This work is concerned primarily with the structural aspects of the heterocyclic dithiadiazolyl and dithiadiazolylium rings. Chapter one reviews both the 7π dithiadiazolyl and the 6π dithiadiazolylium ring systems. The synthetic routes to these ring systems are outlined, as well as the reactions that they are known to participate in. Chapter two outlines the general methods used to synthesise and analyse the compounds prepared and examined in this thesis. Chapter three investigates the crystal structures of various salts containing the dithiadiazolylium ring system. All of these salts possess halide anions, and the relationship between the size of the halogen and its position in relation to the heterocyclic ring is examined. In chapter four the new metallo-dithiadiazolylium species, Hg[CNSNS](_2)[AsF(_6)](-2), is examined as a potential transfer reagent for the dithiadiazolylium ring. The previously unknown halogen-substituted compounds, [X.CNSNS] [AsF(_6)] (X = Br, Cl), have been prepared from this metallo-dithiadiazolylium system. Chapter five outlines the crystal structures of four novel compounds formed by metal-insertion into the S-S bond of the dithiadiazolyl ring. The sixth chapter indicates possible ideas based on the work outlined in this thesis.

No description available.

No description available.

No description available.

No description available.