The nature of ice-sheet damage to overwintering forage plants was studied in a controlled environment at non-injurious freezing temperatures. The soil atmosphere was analyzed in a gas-chromatograph and the plants were assessed for injury by histological examination and recovery rates in the greenhouse. Under experimental ice-covers carbon dioxide accumulated in the soil in some instances to as high as 10% while oxygen was depleted to less than 4% of the atmosphere. Plants rooted in such soils were killed after 7 weeks of ice-cover. When the soil under the ice-sheet was flushed with carbon dioxide the plants were killed after periods as short as 21 days. In both cases injury appeared to be physiological rather than mechanical. Furthermore, carbon dioxide accumulation rather than oxygen depletion was responsible for the injury since the plants were able to withstand periods of 3 weeks in a nitrogen-saturated soil. A freeze-thaw-freeze cycle, with moderate freezing temperatures and associated with an ice-sheet, did not appear to be damaging to alfalfa. Continuous ice-covers resulted in a greater accumulation of carbon dioxide and consequently more injury suffered by the plants than where the cover was temporarily broken by a thaw. High soil-moisture conditions which are usually associated with ice-sheets did not result in an increased hydration level in the tissue and consequently did not make the plants more susceptible to cold injury. A technique was developed to determine the ability of plants to withstand ice-encasement. Several varieties and species that were tested exhibited no clear-cut correlation between resistance to ice encasement and frost hardiness. / Land and Food Systems, Faculty of / Graduate

Two types of experiments involving the Mossbauer atom as a dilute impurity in a host lattice are discussed. For a zero-phonon experiment with Fe⁵⁷ in Pt¹⁹⁵ at room temperature, the expected shift of the central Mossbauer peak is [symbol omitted]/3000. The minimum time required to experimentally determine this shift to within 10% is found to be 16 weeks of counting with a 5 millicurie source. For a one-phonon experiment with Fe⁵⁷ in Pt¹⁹⁵, the count rate due to resonance scattering is found to be 3.14 x 10⁻⁴/sec., and the count rate due to Rayleigh scattering 2.2 x l0⁻²/sec. The case of Fe⁵⁷ in Be⁹ is also discussed. An air trough Mossbauer shift spectrometer constructed to perform the zero-phonon experiment is described. Vibrations present in this apparatus, making it inadequate for experimental work, are discussed. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

[No abstract submitted] / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The plasma calcium level is one of the most precisely regulated constants of the internal environment, and the large reservoir of calcium in the skeleton is primarily responsible for this homeostasis. The experiments presented in this thesis were designed to study quantitatively the regulation of plasma calcium. Acute hypocalcemia was induced by continuous intravenous EDTA infusion (a calcium chelating agent) at a known rate, and hypercalcemia was induced by intravenous calcium gluconate infusion. The rate used in most cases was 10 mg. calcium per kg. for one hour. Both mobilization and storage of calcium appeared to depend on equilibrium with a labile calcium storage pool in bone. The rate of storage or mobilization was shown to be proportional to the amount of blood coming in contact with this labile pool in bone (bone blood flow), and the plasma/bone difference in Ca++ activity. Bone blood flow was measured using the Pick Principle for calcium storage, and it was calculated to be 6.46 ± 0.60% of the cardiac output (14 dogs). The extracellular fluid calcium was also estimated and found to be 15.73 ± 0.72 mg/kg (14 dogs), corresponding to an extracellular fluid volume of approximately 20% of body weight. Less than 5% of the injected calcium was excreted in the urine. The labile calcium storage pool in bone was estimated from the changes in the bone-blood equilibrium after calcium was injected, and was found to be 2 - 5 times greater than the extracellular calcium. The net loss of calcium from the plasma after calcium injection, which is assumed to equal the rate at which calcium is used for bone mineralization less calcium released by resorption, was estimated as 1 - 2 mg. Ca/kg/hr. or 0.15 - 0.35% of the total bone calcium per day. The methods described provide a means of assessing quantitatively the factors involved in acute regulation of the plasma calcium level. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

The theory of the Raman Effect in crystals has been re-examined by O. Theimer (Can. J. Phys. 1956, 34 312) in an attempt to overcome some discrepancies between experimental results and predictions of the theory. New selection rules have been derived by investigating the validity of the assumptions made in the earlier theory. The new theory, applied to the symmetric Raman line of Calcite, predicts that, for the crystal orientated with its optic axis parallel to the illuminated surface, the "forbidden" component will be truly forbidden for forward or backward scattering, while appearing as previously reported for scattering at 90°. The present investigation is concerned with measuring the relative intensities of the polarized components of this line for backward scattering, the measurements being made with the crystal orientated with its optic axis either parallel or perpendicular to the illuminated surface. A method for increasing the scattering volume by joining several crystals along cleavage faces has been developed and a new mercury discharge lamp was designed which gave an appreciable increase of the illumination intensity. The relative intensities of the components of the symmetric Raman line obtained were evaluated by careful consideration of the characteristics of the photographic emulsion used to record them. The results tend to confirm the predictions of the new theory. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Experiments were designed to study the effects of various intensities and durations of light during early development on meristic variation in kokanee and sockeye salmon (Oncorhynchus nerka), pink salmon (O. gorbuscha) and in rainbow trout (Salmo gairdneri). An experiment with sockeye was designed exclusively to test the period of fixation of vertebrae. Among the salmon species rates of hatching and yolk-sac absorption were fastest under the longer light durations and higher intensities. In sockeye and pink an increasing rate of yolk-sac absorption was correlated with increasing amount of light. In trout the rate of yolk-sac absorption showed the opposite results. Mortalities were high under all the experimental conditions. Although meristic variability observed was deemed to be phenotypic yet the affects of selective mortality could not be entirely excluded. Abnormalities in the vertebral column were prevalent in the ‘pre-urostylic' region. The occurrence of abnormal vertebrae was correlated with light only in sockeye. The activities of the pituitary and thyroid glands of trout showed a positive correlation with higher amounts of light. Sockeye scale counts, along the lateral line and on the oblique rows from the origin of dorsal and anal fins to lateral line, were lowest under conditions of higher light and longer durations. Fin ray numbers in all species were the lowest at high light intensities and longer durations. Vertebral counts were lowest at high light intensities and long durations in pink salmon and rainbow trout, but higher in sockeye. At lower light intensities and durations results were variable. Vertebral counts of sockeye increased with increasing light at temperatures of both 8°C and 12°C. Differences among lots at 8°C were significant but those among comparable lots at 12°C were not. The action of light on meristic variability was weak at the higher temperature. It was found in sockeye that vertebral numbers were not fixed before 142 D° and that the period of sensitivity was prolonged (142 D° to 300 D°). / Science, Faculty of / Zoology, Department of / Graduate

[no abstract submitted] / Science, Faculty of / Zoology, Department of / Graduate

The electronic emission spectra of the CO molecule in an applied electric field of 53.8 kilovolts/cm has been observed. The electric field was determined from the Stark Effect on the H line at 4340Å. The spectra were produced in the high field region of a low pressure glow discharge using carbon monoxide gas and water vapour. The electric dipole moment of the CO molecule has been determined for the BlΣ+ state using the P(l) transition of the Ångstrom ( 0 , 0 ) band. The effect observed is a second order effect in the B1Σ+ state and it has been deduced that the dipole moment of the A1π state is very small or zero. The dipole moment of the B1Σ+ state is 1.61 debye ± 14%. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The correlations between moon phases and precipitation maximums were investigated for selected stations in British Columbia in order to determine if they existed for: (a) individual stations; (b) grouped stations; (c) annual occurrences; (d) seasonal occurrences; and (e) geographic areas. The analysis consisted of a graphical presentation and a statistical test for randomness. Graphs of annual and seasonal moving totals for grouped and Individual stations were prepared. They were analyzed for peaks in the configuration of the graphs and for annual and seasonal components through the use of the X2p test. It is apparent from this study that there is a relationship between moon phases and precipitation maximums for grouped stations and individual stations in British Columbia. The evidence for the annual components of "lunar" precipitation for the individual stations shows, statistically, that the distributions are non-random and, graphically, that peaks are visible. Moreover, a shift of the peaks with latitude is discernible for the stations of British Columbia and it is suggested that this shift exists on a global scale. The evidence for the seasonal components of "lunar" precipitation for the individual stations is not as conclusive, either statistically or graphically. The seasonal graphs show peaks but the test for randomness yields inconsistent results. / Arts, Faculty of / Geography, Department of / Graduate

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