Environmental policy makers are required to make decisions under uncertainty regarding the benefits and costs of specific regulatory action. Uncertainty is a phenomenon that cannot be avoided in the assessment of environmental impacts, due to the inherent stochasticity of environmental systems, as well as a lack of adequate empirical data related to specific cause and effect relationships. A primary constraint associated with generation of adequate data from experiments is that environmental research is expensive, and conclusive results may take several years to obtain. In the meantime, significant impacts could be occurring, virtually undetected. A high degree of uncertainty exists in the assessment of the potential effects of ozone (O₃) pollution on agricultural crop yield. Thus, the purpose of this research was to provide information related to the potential impacts of O₃ pollution on crops in the Fraser Valley east of Vancouver, British Columbia, Canada. Two alternate methods were utilized: (i) biomonitoring with Bel W-3 tobacco, a plant variety that is very sensitive to O₃, and (ii) expert judgments of the risks of crop losses from O₃. The biomonitor survey was conducted over three growing seasons (1985 - 1987), in which ambient O₃ pollution conditions were atypically low, limiting the injury response data obtained. However, a correlation was established between biomonitor injury response and ambient O₃ levels, demonstrating that phytotoxic pollution conditions occurred during these years. Calibration of biomonitor injury response with crop yield losses revealed the following: (i) yield losses due to O₃ exposure are likely in the event that biomonitor plants exhibit O₃-induced injury symptoms, and (ii) the absence of biomonitor injury does not preclude the possibility of crop loss, since the O₃ exposure threshold for biomonitor injury may exceed that for loss of certain crops. Although experts are commonly used to provide judgments of potential impacts under uncertainty, there is a paucity of information regarding the desirable attributes of expertise. Selection of experts is largely an ambiguous task, and choices of experts by different persons are likely to be inconsistent. Prior to selection of experts for this project, a comprehensive survey was conducted of over 200 environmental professionals to determine the characteristics of an expert in O₃ effects on crops. It was shown that expertise in this area involves a considerable number of attributes. These were grouped, using factor analysis, into seven independent dimensions: education, type of career experience, length of career experience, cognitive skills, personal qualities related to credibility, scientific recognition and involvement in the scientific community. In general, there was agreement between different groups (e.g., research scientists and members of conservation groups) regarding the relative importance of the various dimensions of expertise. Nine crop loss experts were selected, based on nomination by a large group (166) of their scientific peers. It was demonstrated with regression analysis that nominated experts exhibited the attributes identified in the survey. Logit models were estimated that predict an individual's degree of expertise in O₃ effects on crops, based on specific attributes possessed by that individual. Independent judgments were then obtained from the nine experts regarding probable crop losses under typical O₃ pollution conditions in the Fraser Valley. Probabilistic judgments of crop losses were generally similar among experts and approximated the level of crop losses predicted from the biomonitor survey. Limited empirical exposure-response information for Fraser Valley crops indicated that some cultivars may be more sensitive than assumed by the experts. Additional exposure-response experiments will be required to determine the source of this inconsistency. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

The severe hepatotoxicity of the antiepileptic drug valproic acid (VPA) is believed to be mediated through chemically reactive metabolites. The monounsaturated metabolite 4-ene VPA is steatogenic in the rat, and in a similar fashion to the hepatotoxin 4-pentenoic acid, is thought to be oxidized by mitochondria to a highly reactive α,β-unsaturated ketone, 3-keto-4-ene VPA. The tripeptide thiol, glutathione (GSH), is known to react with a variety of electrophilic compounds that have the potential to interact with cellular macromolecules. The identification and structural characterization of GSH conjugates provides a means of identifying short-lived unstable electrophiles and thus an insight into the mechanisms of toxicity. This thesis describes the synthesis and characterization of thiol conjugates of reactive metabolites derived from the in vivo metabolism of VPA, 4-ene VPA, (E)-2,4-diene VPA, and 4-pentenoic acid. A negative ion chemical ionization gas chromatographic/mass spectrometric (NICI/GC/MS) method for the determination of VPA and 14 of its metabolites in a single chromatographic run was developed. A combination of pentafluorobenzyl and trimethylsilyl derivatization resulted in the [M-181]̄̄̄ ̄anion as the base peak for all the metabolites measured. When these ions were monitored sensitivities in the low picogram range were achieved. The VPA metabolite profile was determined in pediatric patients on VPA monotherapy and on combined therapy with either carbamazepine or clobazam. 4-Ene- and (E)-2,4-diene-VPA were found to be minor metabolites with serum levels below 1% that of VPA. In patients on combined therapy with carbamazepine, the ω and ω-l pathways of VPA metabolism were induced, while products of β-oxidation were significantly decreased. Polytherapy had no significant effect on the serum levels of 4-ene- or (E)-2,4-diene-VPA. Rats were dosed intraperitoneally with 100 mg/kg of the sodium salts of VPA, 4-ene-, (E)-2,4-diene-VPA, 4-pentenoic or (E)-2,4-pentadienoic acids. Methylated bile extracts were analyzed by high pressure liquid chromatography and liquid chromatography/tandem mass spectrometry (LC/MS/MS) for GSH conjugates while urine samples were analyzed by GC/MS and LC/MS for N-acetylcysteine (NAC) conjugates and other metabolites. The GSH conjugate of (E)-2,4-diene VPA was detected in the bile of rats treated with 4-ene- and (E)-2,4-diene-VPA. The NAC conjugate was a major urinary metabolite of rats given (E)-2,4-diene VPA and was a prominent urinary metabolite of those animals given 4-ene VPA. The structures of these metabolites were confirmed by comparing GC/MS or LC/MS properties of the isolated metabolites to those of synthetic standards. The GSH and NAC conjugates of (E)-2,4-diene VPA were chemically synthesized and their structures established to be (E)-5-(glutathion-S-yl)-3-ene VPA and (E)-5-(N-acetylcystein-S-yl)-3-ene VPA by nuclear magnetic resonance spectroscopy and mass spectrometry. In contrast to the very slow reaction of the free acid of (E)-2,4-diene VPA with GSH, the methyl ester reacted rapidly with GSH to yield the adduct. In vivo it appears the diene forms an intermediate with enhanced electrophilic reactivity to GSH as indicated by the facile reaction of the diene with GSH in vivo (about 40% of the (E)-2,4-diene VPA administered to rats was excreted as the NAC conjugate in 24 hr). In rats treated with 4-pentenoic and/or (E)-2,4-pentadienoic acids the following conjugates were identified and characterized by synthesis: GSH and cysteine conjugates of 3-oxo-4-pentenoic acid, GSH and NAC conjugates of (E)-2,4-pentadienoic acid, and the NAC conjugate of acrylic acid. The results thus provided the first direct biochemical evidence for the in vivo formation of the metabolite of 4-pentenoic acid considered responsible for the irreversible inhibition of fatty acid metabolism. The results also revealed basic differences between the mitochondrial metabolism of 4-ene VPA and 4-pentenoic acid. The 3-keto-4-ene VPA and its GSH and NAC conjugates were synthesized in order to facilitate the in vivo identification of these compounds following the administration of VPA, 4-ene-, or (E)-2,4-diene-VPA to rats. However, neither the 3-keto-4-ene VPA nor its thiol derivatives were evident in any of the treatments. The NAC conjugate of (E)-2,4-diene VPA was also found to be a metabolite of VPA in patients. The level of the conjugate appeared to be higher in two patients who recovered from VPA-induced liver toxicity. The characterization of GSH and NAC (in humans and rats) conjugates of (E)-2,4-diene VPA suggests that VPA is metabolized to a chemically reactive intermediate that may contribute to the hepatotoxicity of the drug. / Pharmaceutical Sciences, Faculty of / Graduate

This study was concerned with selecting methods drawn from ecology and ethology that could be applied to evaluating the behaviour of people in downtown public places. Time-sampling and behavioural mapping proved to be useful objective methods of observing and recording people's activities in four public places in Vancouver, British Columbia. Information on user activities was applied to evaluate the relationship between behaviour and the physical environment in a park, a square and two plazas. In each place there were examples of the impact of environmental factors such as sun direction, shadow patterns, wind tunnels, and edge conditions on the location and the intensity of user activities. Too often the design of urban spaces has not been sympathetic to the reactions of people to their surroundings. This inadequacy has brought about a lack of use of these spaces. Traditional techniques of behavioural research have not been able to improve this situation. The observational approach developed here is capable of providing objective information on the ways in which physical surroundings affect people's activities. / Land and Food Systems, Faculty of / Graduate

The Pectoralis major and Pectoralis minor muscles of chicken were given substerilizing doses of ɤ-irradiation at varying times post-slaughter and the pH, shear force, fragmentation, and color were evaluated. pH measurements in an iodoacetate slurry showed that doses up to 300,000 rads administered at ⅕ or 5 hours post-mortem had no effect on either rate of pH fall or final pH. Irradiation at 2, 5t or 12 hours did not change the final pH taken at 48 hours post-mortem. Excised P. major muscles cooked by boiling between aluminium plates required more shear force at the posterior portion than at the anterior. Irradiation dose levels from 30,000 to 300,000 rads on P. major increased shear resistance over unirradiated muscles. The earlier the time of application (2, 5 and 12 hours post-slaughter) the greater the increase in toughness when measured at 60 hours post-slaughter. The 300,000 rad dose at 12 hours, given after attainment of maximum inextensibility and relaxation of isometric tension, still produced a significant loss in tenderness. The irradiation generally reduced the degree of myofibrillar fragmentation after a standardized blending treatment, although the decrease was not always significant. Pasteurizing irradiation produced a pink color in raw muscle stored aerobically for 55 hours that increased with dose. Peaks typical of an oxymyoglobin-like compound emerged and the dominant wavelength was shifted toward longer wavelengths by 4 nm. After cooking there was no visible color difference between irradiated and control muscles. Correlations between these parameters on control muscles indicated that the pH decline was positively correlated to shear force, although not of high value. The fragmentation ratios were not significantly correlated with shear force. / Land and Food Systems, Faculty of / Graduate

The role of natural earth licks in the ecology of the mountain goat (Oreamnos americanus (Blainville)) was studied during the summers of 1965 and 1966 in the Rocky Mountain Trench of southern B.C. The patterns of movements of the animals were determined as they used the licks and the vegetation, lick soils and blood serum were analyzed with respect to sodium content. The predicated use of licks as suggested by other workers involves the idea that sodium may be the attracting element. The present study examined seasonal and differential patterns of movement, along with periodicity of use, in order to determine the resultant interplay of animal movement and sodium and water content of the vegetation. The goat encounters such additional risks as predation, parasitism, hunting and joint use while using the lick seasonally. Since the goats use the lick differentially in time, each sex is affected to a different degree by the above factors. Differential use also produces characteristic patterns of grouping and molting. Periodicity of use occurred mainly in the afternoon, although distance travelled and complexity of the lick may affect time of entry, length of stay and group size. The frequency of use differed at each lick, with the average time of use by an individual being one to three weeks. Environmental factors such as temperature and weather appear to regulate the movement to and from the lick. Analysis of the vegetation revealed that sodium was extremely low and that potassium was present in sufficient quantities to meet the requirements of the animal. No significant trends were found to exist from spring to fall or due to changes in elevation, as far as sodium and total ash were concerned. Observations indicated that animals select certain licks over others and select sites within a lick. These high licking sites were shown to have a higher sodium content. Newly established licks had a higher sodium content than did old licks, however, highly preferred sites were not always higher in calcium, phosphorus or cobalt. A normal range of serum sodium values was established for the goat but due to the regulatory function of the kidney, changes in serum sodium due to lick use could not be detected. Serum sodium decreased with age. A female with a kid had a low serum value. It appears that the level of deficiency causing the craving is not sufficient to show up in serum analysis. Animals died during trapping operations and a selenium deficiency was suspected. Gross symptoms approximated those attributed to white muscle disease and the vegetation contained selenium in amounts which are known to cause this myopathy. / Science, Faculty of / Zoology, Department of / Graduate

The effect of pasteurizing dose levels of irradiation on the lipid and protein fractions of raw bovine muscle was studied by chemical amalysis and taste panel evaluation. The following storage conditions were evaluated: (a) Long term anaerobic storage at 39°F (b) Short term aerobic storage at 39°F (c) Frozen storage at -10°F (d) Cooking and short term aerobic storage at 39°F. Free fatty acid content increased with time of storage at 39°F. Irradiation with 1 Mrad of γ irradiation depressed free fatty acid development. During frozen storage the unirradiated sample was significantly higher in free fatty acids than the irradiated samples (0.1 Mrad and 0.5 Mrad). The quantity of phospholipid was reduced by both aerobic and anaerobic storage but no significant difference was evident between irradiated and unirradiated samples. The formation of free amino acids during storage was retarded by irradiation. A significant difference in flavour between control samples and those which received 0.5 Mrad of irradiation was found consistently by taste panel evaluation. The flavour difference resulted from characteristic irradiation odour. Rancid flavours were not detected by the panel. Thiobarbituric reactive substances (TBRS) increased during short term aerobic storage, however a significant difference did not exist between irradiated and unirradiated samples. During long term anaerobic storage the TBRS of irradiated samples increased faster than that of unirradiated samples, but the difference was relatively small. During frozen storage TBRS increased in direct proportion to the level of irradiation. Aerobic storage of cooked meat at 39°F resulted in a rapid increase of TBRS but the level was not affected by irradiation. / Land and Food Systems, Faculty of / Graduate

In 1985, Mendelson and Gorzalka proposed the dual role hypothesis of serotonergic modulation of lordosis behaviour. In this hypothesis it was proposed that serotonergic activity can either inhibit or facilitate lordosis behaviour. Specifically it was suggested that the lordosis-inhibiting effects of serotonin are mediated by activity at 5-HT₁ receptors, whereas lordosis-facilitating effects of serotonin are mediated by activity at 5-HT₂ receptors. The purpose of the following series of studies was both to confirm and to extend the dual role hypothesis. The intraperitoneal administration of the 5-HT2 antagonists pizotefin (1 mg/kg), cyproheptadine (1 mg/kg), metitepine (1 mg/kg), and ketanserin (1 mg/kg) were found to inhibit lordosis behavior in ovariectomized rats that had been primed with estradiol benzoate (EB) and progesterone (P). Pipamperone was ineffective. The 5-HT₂ agonist guipazine (3 mg/kg) was ineffective alone, but it reversed the inhibitory effects of pizotefin, cyproheptadine, and ketanserin. It did not reverse the effects of metitepine. The highly selective 5-HT₂ antagonist LY53857 (0.3 mg/kg) was also found to inhibit lordosis behaviour in female rats that had been primed with EB and P. The lordosis-inhibiting effect of LY53857 (1 mg/kg) in females primed with EB and P was reversed by quipazine (3 mg/kg). The nonselective 5-HT antagonist methysergide (7 mg/kg) was found to inhibit lordosis behavior 30 min after intraperitoneal administration to females treated chronically with EB, or with EB and P. However, methysergide was found to facilitate lordosis behavior 200 and 300 min after administration to female rats treated acutely with EB. In an analysis of dose response it was found that methysergide (0.02 - 7 mg/kg) administered 30 min prior to behavioural testing produced no facilitation of lordosis in females primed with EB. However, when administered 200 min prior to testing, methysergide (1 mg/kg) produced a significant facilitation of lordosis. The administration of the 5-HT₁ A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH DPAT) inhibited lordosis behavior in ovariectomized rats primed with EB. 8-OH DPAT was ineffective at 0.01 mg/kg, whereas inhibition occurred at the 0.03, 0.1, 0.3, 1.0, and 3.0 mg/kg doses. In an evaluation of the effects of 8-OH DPAT on the expression of male sexual behaviour by females treated chronically with testosterone, 8-OH DPAT ( 1 mg/kg) increased the number of females mounting and significantly increased mount frequency. The 5-HT₁ A agonists ipsapirone (0.1 mg/kg) and gepirone (0.3 mg/kg) facilitated lordosis in females treated with EB. When administered at higher doses, ipsapirone (3.0 mg/kg) and buspirone (3.0 mg/kg) inhibited lordosis in rats treated with EB. In females treated with EB and P, ipsapirone (> 1.0 mg/kg), gepirone (> 0.3), and buspirone (> 0.3) inhibited lordosis behaviour. The newly developed 5-HT₁ A antagonist BMY 7378 (0.2 mg/kg) facilitated lordosis behaviour in females treated with EB. However, this facilitation was no longer apparent at the 5 mg/kg dose. BMY 7378 (0.04 - 5 mg/kg) was ineffective in females primed with EB and P. The 5-HTTB agonist 1 -(3-trifluoromethylphenyl)piperazine (TFMPP, 0.2 -5 mg/kg) was found to facilitate lordosis in females treated with EB. In females primed with EB and P, TFMPP (5 mg/kg) produced a significant inhibition of lordosis. The 5-HT₁ B agonist m-chlorophenylpiperazine (MCPP, 0.04 - 5 mg/kg) was ineffective in females primed either with EB or with EB and P. The 5-HT₃ Antagonist ICS 205-930 (5 mg/kg) was found to facilitate lordosis behaviour, whereas the 5-HT₃ Antagonist MDL 72222 (0.05 - 5 mg/kg ) was found to be ineffective in females primed with EB. The results of these studies tend to confirm that serotonergic activity can either inhibit or facilitate lordosis behaviour. It is suggested that the lordosis-inhibiting effects of serotonin are mediated by activity at postsynaptic 5-HTTA and possibly 5-HT₃ Receptors. The lordosis-facilitating effects of serotonin are mediated by activity at 5-HT₂ and possibly presynaptic 5-HT₁ B receptors. Finally, it is suggested that activity at somato-dendritic 5-HT₁ A autoreceptors may mediate facilitatory effects of low doses of 5-HT₁ A agonists. In closing, there is a discussion of the implications these results might hold for the understanding of the effects of serotonergic drugs on human behaviour. / Arts, Faculty of / Psychology, Department of / Graduate

The aim of this thesis is to analyse the effects of euro adoption on the economy. The main focus is to describe situation in Slovakia as a new member state of eurozone and to examine stages of preparation for euro adoption of other former V4 members -- Czech Republic, Hungary and Poland. The economy of all countries is strongly influenced by world financial crisis, effects of which are definitely being considered and reflected in this depiction.

The world is experiencing a growing demand for miniaturised products. Micro-milling, using carbide micro tools has the potential for direct, economical manufacture of micro parts from a wide range of workpiece materials. However, in previous studies several critical issues have been identified that preclude the direct application of macro machining knowledge in the micro domain through simple dimensional analysis. The research presented in this thesis focused on some of the areas that require development of the scientific knowledge base to enable determining improved microscale cutting performance. In the mechanical micro machining of coarse grained materials, the programmed undeformed chip thickness can be lower than the length scale of the workpiece grains. Moreover, when the microstructure of such materials is composed of more than one phase, the micro cutting process can be undertaken at a length scale where this heterogeneity has to be considered. Driven by this challenge, the material microstructure 'size effect' on micro-machinability of coarse grain steel materials was investigated in this PhD. In this regard, a predominantly single phase ferritic workpiece steel material and another workpiece material with near balanced ferrite/pearlite volume fractions was studied over a range of feedrates. The results suggested that for micro machined parts, differential elastic recovery between phases leads to higher surface roughness when the surface quality of micro machined multiphase phase material is compared to that of single phase material. On the other hand, for single phase predominantly ferritic materials, reducing burr size and tool wear are major challenges. In micro machining the so called 'size effect' has been identified as critical in defining the process performance. However, an extensive literature search had indicated that there was no clear reported evidence on the effect of process variables on driving this size effect phenomenon. It is often assumed in literature that the un-deformed chip thickness was the main factor driving the size effect. This limit manufactures to only altering the feedrate to try and influence size effect. To explore the significance of a range of inputs variables and specifically, cutting variables on the size effect, micro cutting tests were conducted on Inconel 718 nickel alloy. Taguchi methodology along with signal processing techniques were applied to micro milling acoustic emission signals to identify frequency/energy bands and hence size effect specific process mechanism. The dominant cutting parameters for size effect characteristics were determined by analysis of variance. These findings show that despite most literature focussing on chip thickness as the dominant parameter on size effect, the cutting velocity is a dominant factor on size effect related process performance. This suggests that manipulating the cutting speed can also be a very effective strategy in optimising surface finish in micro machining and in breaking the lower limit of micro machining.In micro machining the lower limit of the process window is set by the minimum chip thickness. Identifying this limit is thus important for establishing the process window. Process windows are valuable guidelines for industrial selection of cutting conditions. Additionally, understanding factors that influence the value of minimum chip thickness is even more important for progressing micro machining capability to the nano-scale machining regime. For this reason, in this PhD study, acoustic emission signatures emanating from microscale milling of six different workpiece materials were characterised to identify the rubbing mode and this enabled the identification of the threshold conditions for occurrence of minimum chip thickness. The minimum chip thickness predicted by this novel approach compares reasonably well to the values that exist in published literature. Additionally, the decomposition of raw acoustic signal allowed the determination of energy levels corresponding to deformation mechanisms. The PhD work provides significant and new knowledge on the utility and importance of acoustic emission signals in characterising chip formation in micro machining. A novel method for determining the minimum chip thickness was developed, micro machining chip formation mechanisms were identified and the machinability of coarse grained multiphase material is presented.

Mn was found to reduce the toxicity of Cu to the marine diatom Thalassiosira pseudonana (clone 3H) in the chemically well defined medium Aquil (Morel et al., 1979), verifying the results of Sunda and Huntsman (1983). A cation-exchange resin technique developed by Zorkin (1983) was modified for use in natural seawater samples to estimate the biologically active Cu and Mn. Seawater samples taken from the bottom waters of a local fjord were found to support better growth of the test organism than samples from shallow waters, although the concentration of the biologically active Cu as estimated by the resin technique was similar for samples collected from all depths. The biologically active Mn concentration was found to be higher in the bottom water samples, indicating that the bioassay organism was probably responding to the interaction between the ionic forms of Cu and Mn, rather than to changes in the biologically active Cu concentration. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate