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The public nuisance and health concerns caused by odours from livestock facilities are among the key issues that affect neighbouring communities and the growth of the livestock industry across Canada. A setback distance is the common regulatory practice to reduce odour impact on the neighbouring areas. The air dispersion modeling method may be a more accurate tool for establishing setback distances since it considers site-specific airborne emissions, such as odour and gases from the animal production site as well as weather conditions and then estimates a concentration of the pollutant (odour, ammonia, etc.). Although various dispersion models have been studied to predict odour concentration from agricultural sources, limited field data exist to evaluate their applicability in agricultural odour dispersion. Thus, the purpose of this project was to evaluate the selected commercial air dispersion models with field plume measurements from swine operations. <p>Firstly, this thesis describes a sensitivity analysis of how the climatic parameters affect model simulations for four selected air dispersion models, ISCST3, AUSPLUME, CALPUFF, and CALPUFF. Under the steady state weather condition, mixing height had no effect on the livestock odour dispersion, while atmospheric stability, wind speed and wind direction had great effect on the livestock odour dispersion. Ambient temperature had a moderate effect compared with other parameters. Under variable weather conditions, the predicted odour concentrations were much lower than the results under steady state weather conditions. <p>A series of comparisons between model predictions of the same four models and field odour measurements were conducted. When using the livestock odour plume measurement data from University of Manitoba, three equations were used to convert the model predicted odour concentration to field measured odour intensity. The equations did not predict odour intensity very well. No model showed obvious better performance than the others. Scaling factors did not improve the results considerably. When using the odour plume measurement data from University of Minnesota, INPUFF2 performed better than CALPUFF. Scaling factors did improve the modeled results. When using the odour plume measurement data from University of Saskatchewan, INPUFF2 also performed better than CALPUFF. Scaling factors were still useful for the results improvements.<p>Finally, because CALPUFF is the US EPA preferred model and predicted the highest values under variable weather conditions in the sensitivity study, we used it to simulate odour plumes on selected three swine sites using hourly weather data from 1993 to 2002 in Yorkton, Saskatchewan. The maximum predicted distance were 2.9 km for 1 OU, which was lower than the recommended maximum setback distance of 3.2 km. <p>It is recommended that the variable weather conditions be used in the setback distance determination. CALPUFF is the preferred model and INPUFF2 is another option for field odour plume simulation, however scaling factors are needed to bring the model predictions close to the field measured results. Because the models evaluated were not developed for odour dispersion simulation, a model that can accurately predict livestock odour dispersion should be developed to take into account of the difference between odour and gas and wind direction shifts within the simulation time interval.

The public nuisance and health concerns caused by odours from livestock facilities are among the key issues that affect neighbouring communities and the growth of the livestock industry across Canada. A setback distance is the common regulatory practice to reduce odour impact on the neighbouring areas. The air dispersion modeling method may be a more accurate tool for establishing setback distances since it considers site-specific airborne emissions, such as odour and gases from the animal production site as well as weather conditions and then estimates a concentration of the pollutant (odour, ammonia, etc.). Although various dispersion models have been studied to predict odour concentration from agricultural sources, limited field data exist to evaluate their applicability in agricultural odour dispersion. Thus, the purpose of this project was to evaluate the selected commercial air dispersion models with field plume measurements from swine operations. <p>Firstly, this thesis describes a sensitivity analysis of how the climatic parameters affect model simulations for four selected air dispersion models, ISCST3, AUSPLUME, CALPUFF, and CALPUFF. Under the steady state weather condition, mixing height had no effect on the livestock odour dispersion, while atmospheric stability, wind speed and wind direction had great effect on the livestock odour dispersion. Ambient temperature had a moderate effect compared with other parameters. Under variable weather conditions, the predicted odour concentrations were much lower than the results under steady state weather conditions. <p>A series of comparisons between model predictions of the same four models and field odour measurements were conducted. When using the livestock odour plume measurement data from University of Manitoba, three equations were used to convert the model predicted odour concentration to field measured odour intensity. The equations did not predict odour intensity very well. No model showed obvious better performance than the others. Scaling factors did not improve the results considerably. When using the odour plume measurement data from University of Minnesota, INPUFF2 performed better than CALPUFF. Scaling factors did improve the modeled results. When using the odour plume measurement data from University of Saskatchewan, INPUFF2 also performed better than CALPUFF. Scaling factors were still useful for the results improvements.<p>Finally, because CALPUFF is the US EPA preferred model and predicted the highest values under variable weather conditions in the sensitivity study, we used it to simulate odour plumes on selected three swine sites using hourly weather data from 1993 to 2002 in Yorkton, Saskatchewan. The maximum predicted distance were 2.9 km for 1 OU, which was lower than the recommended maximum setback distance of 3.2 km. <p>It is recommended that the variable weather conditions be used in the setback distance determination. CALPUFF is the preferred model and INPUFF2 is another option for field odour plume simulation, however scaling factors are needed to bring the model predictions close to the field measured results. Because the models evaluated were not developed for odour dispersion simulation, a model that can accurately predict livestock odour dispersion should be developed to take into account of the difference between odour and gas and wind direction shifts within the simulation time interval.

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An ambient odour of anise was used in a context-dependent memory study with three different memory tasks targeting both declarative and non-declarative memory functions. Declarative memory was assessed by means of two episodic memory tests; recall of a prose text and a complex figure. Priming was used to assess the non-declarative memory with word fragment completion. Memory was tested immediately and after 48 hours. The results showed a significant main effect of context (odour or not) for all three tests in favour of the olfactory context. In addition, a significant main effect of time was observed for all three tests and a significant interaction effect between context and time for the priming test were observed. This interaction showed that the priming effect was equal in size across both conditions at immediate testing, although when the odour was reinstated at the delayed test the results showed larger priming relative the control condition.

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The Drosophila larva is a suitable model to study olfaction due to its numerical simplicity. The peripheral olfactory system consists of just 21 pairs of olfactory sensory neurons (OSNs), each expressing one, or at most two classes of olfactory receptors (ORs) that define the receptive range of the OSN. Larvae produce robust behaviours to many odours and are easily genetically manipulated. Unlike audition, relatively little is known regarding olfaction due to its complex nature - most odours exist as multimolecular units that vary in their identity and structure, concentrations and proportions. Until recently, most olfactory research has focused on the processing of simple odours, which does not realistically model real-world odours. Presented here is one of the first in situ investigations of odour mixture processing in the Drosophila melanogaster larva. Processing of odour mixtures was explored using both electrophysiological recordings of the peripheral olfactory system and behavioural assays at the output of the system, and the effects of various factors on responses were also explored. w1118 larvae in which all OSNs were functional, and larvae with only a single class of OSN (using the Gal4-UAS expression system) were studied. At the peripheral level, mixture responses were never entirely transformed from the components, and were always as large as or greater than the response to the strongest component, and therefore the neuron was either 'seeing' just one or more than one of the components, respectively. Mixture responses across all OSNs were always additive, hypoadditive or partially suppressive, and there were no instances of synergistic or fully suppressive responses. Peripheral mixture responses were both OR- and component-dependent, as the same mixture was represented differently across OSNs. At the behavioural level, mixture responses were mostly additive, partially and fully suppressive and therefore not always predictable from the components. Interestingly, responses of larvae with only a single class of OSN were mostly predictable as there was no complexity of processing arising from the combinatorial code. When all OSNs were functional and the combinatorial code appropriately activated, mixture responses were more complex and unpredictable. Associative conditioning experiments revealed that larvae were unable to identify components from within a mixture, providing evidence that, at least at the behavioural level, mixture responses were probably synthetic, and therefore likely that interactions between the components occurred at some point along the processing pathway. Mixtures were often dominated by the component inducing the largest firing rate, and carbon chain length and vapour pressure influenced, to some degree, which component dominated. The nature of mixture responses were affected by concentration which is consistent with a model of receptor competition - at low concentrations mixture responses were additive, whilst at high concentrations responses were reduced compared to an additive response. In contrast, prior experience had little effect on peripheral responses to pure odours and mixtures, although rapid adaptation was observed during exposure. Exposure did have an effect on subsequent behavioural responses to pure odours and mixtures, providing evidence of central effects of adaptation. The data presented here provides evidence that mixture processing is extremely complex, with many factors influencing and affecting the way that the system responds to mixtures. This data reveals an unexpected complexity in a numerically simple system and with such'simple' complex odours, and indicates the likelihood of more complex responses when all OSNs are functional.

The factors determining the generation of aroma in starch extrudates containing added ingredients with aroma precursors were elucidated. Analyses were performed using headspace analysis of raw materials and extrudates and subsequent analysis by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Olfactometry (GC-O. Study I described the volatile, amino acid and fatty acid profiles of Hydrolised vegetable protein (HVP)and Soy protein isolate (SPI). Studies II, III and IV descibed the volatiles developed from extrusion of different feedstocks under mild and extreme processing conditions. Wheat starch was chosen as the carrier.A comparison of the influence of the three different ingredients HVP, SPI and glucose, added to the starch feed, showed the formation of Strecker aldehydes and Maillard-type compounds were significantly affected by the addition of these ingredients. The work in this thesis demonstrated that the addition of ingredients such as HVP, SPI, glucose, cysteine, cysteine-HCI, modifies the aroma of wheat starch extrudates. Furthermore, it showed the changes in conditions of extrusion and pH will greatly influence the aroma profile of the products. / Doctor of Philosophy (PhD)