Higher Degree Theses

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Innovation in science curriculum a Sierra Leone case study
(The University of Waikato, 1991) Baimba, Andrew Augustine; Katterns, Robert; Kirkwood, Valda
Recent studies in philosophy of science and learning theory have identified elements that add a socio-cultural dimension to science curriculum debates. These suggest that effective science education must take account of the culture in which it is being offered. Accordingly, the present study conducted in Sierra Leone investigated the viability of a junior secondary school science curriculum that took into account the childrens’ traditional culture. The investigation involved two parts. The first was a case study examining the present state of junior secondary school science education in Sierra Leone using data derived from a survey which canvassed teachers’ perceptions of science and students’ attitudes towards it. The second involved action research in which a group of teachers worked with the researcher to develop, trial and self-evaluate teaching packages in physics based on the Science for All curriculum, an approach that is based on the constructivist view of learning. The main intent of the study was to investigate first, the effects on their professional development of the teachers’ interaction with the new curriculum and, secondly, their students’ attitudes towards science. The research instruments employed were interviews, classroom observation and an attitudes to science questionnaire. The initial case study showed that the present junior secondary school science programme in Sierra Leone was characterised by: 1. Unfavourable students’ attitudes towards science. 2. Low numbers of General Science teachers with subject expertise in Physics and Chemistry. 3. A lack of sense of direction in determining goals and objectives. 4. Inadequate pre-service teacher education preparation. 5. Limited teacher understanding of recent changes in the thinking about the nature of science and the ways of acquiring scientific knowledge. Successful use of the new curriculum to overcome these problems was hindered by the teachers’ scepticism about the new curriculum, a gap between their theoretical and practical understanding of the change process, and insufficient skills to implement the revised curriculum. Techniques employed to alleviate these problems during the action research suggested that teachers’ commitment could be increased by clarifying conceptually the need for innovation. The researcher’s support and encouragement throughout the curriculum trials significantly helped teachers to give practical expression to their theoretical understanding of the change process. Action research with the new curriculum brought about major changes in the teachers’ approach to teaching. They showed evidence of appreciating recent constructivist views about the nature of science and the ways of acquiring scientific knowledge. The development of their own effective and more relevant curriculum also enhanced the teachers’ self esteem. But even though the teachers with their new found confidence believed otherwise, post-test results showed that students’ attitudes to science were not enhanced by their interaction with the new curriculum. The results of the study suggest policy implications for Sierra Leone. The educational system and science curricula need to dwell far less on western-type syllabuses and public examinations and develop instead science curricula that bridge school science and students’ everyday application of scientific ideas in their traditional settings. Nevertheless, much research is required to identify cultural aspects that can be linked to the school science curriculum. Concomitantly, there is need to research the viability of both preservice and inservice teacher education programmes that can bring about the bridging referred to. The present action research study is a beginning.
The influence of subsoiling on soil physical properties and pasture production
(The University of Waikato, 1992) Chapman, Richard; Allbrook, R.F.
In many areas of New Zealand, soils under pasture have become compacted by a combination of livestock trampling, use of heavy machinery and natural processes, or in the case of sports fields, heavy use at high moisture levels. These processes create soil horizons that have a high resistance to a penetrometer, often a high bulk density and hence a lowered porosity. These horizons reduce hydraulic conductivity, change soil moisture characteristics and restrict root elongation and consequent pasture yield. An arable type subsoiler was re-designed for pasture use and its effects on five soils in the Hamilton Basin were investigated. Soil disturbance was assessed for differing operational depths, tip sizes, operating modes and soil moistures. Soil physical characteristics such as bulk density, soil strength, pore space, water tension and infiltration were measured at intervals after subsoiling. Root growth and yield response of pasture were quantified. Subsoiling in the vibrating mode under relatively dry soil conditions increased soil disturbance by 30% in comparison with non-vibrating; wide tips in comparison with narrow tips increased disturbance by up to 100%. Results indicated that the effectiveness of subsoiling at a standard speed, is a function of operational depth, tip size, pitch angle, soil type and soil moisture. Generally subsoiling below 45 cm depth resulted in a reduction in soil disturbance and was less effective under wet soil conditions at deeper than 35cm Increased water stress in and around the subsoiled slot resulted from summer subsoiling. The addition of press rollers reduced evaporation and reduced ground heave by 25%. Measurements of ground heave following subsoiling using a purpose built heaveometer enabled comparisons between different soils to be made. The more clayey Hamilton and Whatawhata soils showed greatest heave. Subsoiling reduced bulk density by up to 30% within 10 cm distance of the subsoil slot; significantly reduced levels were sustained at this distance in the more clayey soils for up to two years. The effect on bulk density decreased with distance from the subsoil slot. Bulk density estimations in situ showed greater changes in response to subsoiling than laboratory measurements. Penetrometer measurements provided additional crucial information on the extent of soil disturbance and its sustainability with time. Repeated measurements defined “envelopes” of soil disturbance emanating from the subsoiled shank and tip. The lowest soil penetration resistance was found down the slot, where strengths were commonly reduced from 4 MPa to 1 MPa. The depth of influence was shallower further from the slot following a 45 - 50° angle up from the subsoiler tip to the surface. In the more clayey soils a discrete zone of higher strength soil was occasionally identified contiguous to the lateral extremeties of disturbance. Subsoiling shattered large aggregates thus creating a larger volume of soil. Soil mixing was limited to a relatively small area around the subsoiler shank and tip where 17 - 19% of A and B horizon aggregates interchanged. Consequently a redistribution of soil texture and organic matter occurred within soil profiles. Pores >9.76 μm increased from 20 to 35% in A horizons and from 3 to 35% in B horizons. Increased porosity to the full depth of soil disturbance resulted in rapid movement of excess summer rain, and in the case of the poorly drained Whatawhata soil drier soil conditions prevailed in winter. Measurements of root elongation, together with SEM analysis showed that grass roots had difficulty penetrating high bulk density (1.35 - 1.50 Mg m⁻³), high strength (>5.00 MPa) soil layers. In these cases subsoiling facilitated increases of up to 20% in root length and a consequent increase in pasture yield of up to 17.7%. The more clayey soils derived greater benefits from subsoiling than sandy soils, both in the extent of soil disturbance and duration of reduced bulk density and soil strength. In the case of an artificially constructed soil, near surface compaction was ameliorated with a consequent improvement in turf. Provided that subsoiling was carried out under optimum conditions, a positive response in pasture yield could be expected, even where soil physical properties were not limiting. Re-compaction rates following subsoiling are a function of pasture management and soil physical properties, but provided subsoiling is carried out with optimal soil disturbance, then a subsoiling frequency of two years for sandy soils and three years for more silty and clayey soils is recommended.
Characterisation and fate of bleached kraft mill effluents from a New Zealand pulp and paper mill
(The University of Waikato, 1990) Stuthridge, Trevor Raymond; Langdon, Alan G.; Wilkins, Alistair L.
The wastewater discharges from the Kinleith mill, a New Zealand integrated bleached kraft pulp and paper mill, were characterised and their treatability assessed. The chlorination stage bleaching effluents from the mill’s second bleach plant [(C30D70)EoDED sequence] contained a group of novel chlorinated compounds. Fourteen compounds were isolated from the effluents by a combination of liquid-liquid extraction, column chromatography, and preparative gas chromatography. Mass spectral and ¹H and ¹³C NMR data showed these compounds to be hydroxylated and/or chlorinated derivatives of Pinus radiata monoterpenes. The major compounds were a dichlorobornane and four dichloro-p-menthane-1,8-diols. The chlorinated monoterpenes were detected in total concentrations of 1400-12 300 μg L⁻¹ [70-600 g air-dried tonne⁻¹ (ADT) bleached pulp] and they were the major class of low molecular weight extractable organic compounds present in the chlorination stage effluent. The principal factor determining their formation appeared to be the high concentration of monoterpenes remaining in the Pinus radiata brown stock produced in the mill’s continuous digester. The biological activity of the chlorinated monoterpenes was assessed. The chlorinated monoterpene alcohols were base labile with a 94% decrease in concentration being observed within 4 hours at pH 12. The chlorinated monoterpene hydrocarbons exhibited a lesser degree of alkaline lability. Acute toxicity tests on the monoterpene alcohols gave EC₅₀ concentrations of 60-200 mg L⁻¹, indicating that these compounds display relatively little toxicity. The monoterpene alcohols were also tested for mutagenicity and genotoxicity. Some of these compounds produced mutagenic and genotoxic responses. An assessment of the bioaccumulation potential of the chlorinated monoterpene alcohols showed them to have log Kₒw values of 1.37-2.1. Therefore, these compounds are unlikely to exhibit a significant bioaccumulation propensity. Treatment of the chlorination stage effluents in an aerated lagoon treatment system removed 80% of the chlorinated monoterpene alcohols but only a small fraction of the monoterpene hydrocarbons. It was concluded that these compounds were unlikely to produce significant environmental effects in the recipient. The mill has two secondary treatment systems. The relative effectiveness of each of these was assessed. The two systems operate in different configurations. Treatment system A, which receives general mill wastewaters and chlorination stage bleaching discharges utilises deep, aerated lagoons and has a 4.5 day retention time. Treatment system B, which receives alkali extraction bleaching wastewaters and foul condensates, uses a lagoon system with a retention time of 51 days. Detailed chemical analyses of the untreated and treated wastewaters were made. Mass balances were calculated for a range of physical parameters and for specific chlorinated and non-chlorinated organic constituents. Significant differences in the treatability of various constituents were found. In particular, while system A was able to reduce levels of adsorbable organic halide (AOX) by 65%, no significant reduction in AOX occurred in system B. In contrast, system B reduced levels of chloroacetic acids by 84% while system A did not achieve any statistically significant removal of these compounds. The treatability of chlorophenolic compounds also differed. System A was unable to remove chlorophenols and chloroguaiacols while system B did not reduce levels of chlorocatechols. The removal of AOX from effluents treated in system A was high compared to published data and an assessment was made of possible mechanisms for the observed AOX removal. Much of this removal took place in a short section (3.3 hr residence time) of the system’s main lagoon. The initial AOX decrease in the aqueous phase could be achieved in part by settling of AOX-containing suspended solids from the influent wastewaters. In addition, lime and bacterial solids present in the treatment system were able to adsorb AOX from the influent wastewaters. Only a small proportion of the organic chlorine removed was found in sludges. A mass balance of aqueous and solid phases indicated that over 99% of the removed AOX was mineralised.
Control of glucose and xylose utilization by Clostridium thermohydrosulfuricum Rt8.B1
(The University of Waikato, 1992) Cook, Gregory Murray; Morgan, Hugh W.; Janssen, P.H.
Five extremely thermophilic organisms representing the Eubacterial and Archaebacterial Kingdoms were studied for controlled expression of β-galactosidase, β-glucosidase and α-glucosidase synthesis. Under the culture conditions used, these organisms exhibited a high constitutive level of enzyme synthesis which was modulated in the presence of added carbohydrate. The lack of observed classical induction in these organisms could either reflect a lack of control or a less elaborate control of enzyme synthesis, which may be advantageous to these bacteria in environments low in nutrients. This absence of highly regulated control is common in thermophilic organisms and may be a reflection of the limited evolutionary divergence of thermophiles as is suggested by phylogenetic studies. Cl. thermohydrosulfuricum Rt8.B1 inhabits thermophilic environments where the natural concentrations of sugars would be expected to be quite low. The results of this study demonstrated that glucose and xylose were used simultaneously i.e. the bacterium exhibited hyperbolic growth when both glucose and xylose were supplied together at nonlimiting concentrations. Under conditions of hyperbolic growth, Cl. thermohydrosulfuricum Rt8.B1 exhibited neither catabolite repression nor inducer exclusion. Although classical control mechanisms were not seen, the utilization of glucose and xylose were tightly controlled at both low and high concentrations of single and multiple substrates. Such regulation to allow controlled hyperbolic growth is consistent with the idea of Cl. thermohydrosulfuricum Rt8.B1 being well adapted as an opportunist. The transport of glucose and xylose across the bacterial cell membrane of Cl. thermohydrosulfuricum Rt8.B1 was governed by permeases which did not catalyze concomitant substrate transport and phosphorylation, and thus was not a phosphoenolpyruvate-dependent carbohydrate: phosphotransferase system. Glucose and xylose transport was not driven by a proton motive force (ΔμH⁺) nor coupled to sodium and potassium ion gradients. An involvement of ATP in the uptake process was indicated by the reduction of glucose and xylose uptake by iodoacetate and sodium fluoride, both inhibitors of ATP synthesis. The phosphorylation of glucose was carried out by a constitutive ATP-dependent glucokinase and that of xylose by an inducible ATP-dependent xylulokinase following isomerization by xylose isomerase. These enzymes not only initiated the metabolism of glucose and xylose in Cl. thermohydrosulfuricum Rt8.B1, but also served to “capture” sugars from the cytoplasm through their phosphorylation. Since glucokinase was regulated primarily by the concentration of ATP, ADP, and AMP, both glucose phosphorylation and uptake appeared to be dependent upon the energy status of the cell. Xylulose inhibited glucokinase activity, indicating that xylose metabolism may regulate the activity of glucokinase in glucose and xylose-grown cells. Xylose utilization by Cl. thermohydrosulfuricum Rt8.B1 was mediated by two systems. Both systems were inducible and dependent on the xylose concentration used for cell growth. Cells grown on 5 mM xylose had a high-affinity, low-capacity system for xylose uptake which was saturable (low Vₘₐₓ). Cells grown on 50 mM xylose had a low-affinity, high-capacity (high Vₘₐₓ) system for xylose uptake and the kinetics were indicative of facilitated diffusion. The xylose isomerase of Cl. thermohydrosulfuricum Rt8.B1 had a high Kₘ for xylose (low-affinity) and xylulokinase had a low Kₘ for xylose (high-affinity). The Kₘ for xylulokinase was lower than the Kₜ for the high-affinity xylose permease; this indicated that the xylulokinase phosphorylating system was fully saturated at external xylose concentrations near or above the Kₜ concentration for uptake and that the affinity of xylulokinase regulated both the rate of xylose uptake and its subsequent utilization. When Cl. thermohydrosulfuricum Rt8.B1 was grown on high concentrations of xylose (low-affinity), xylulose leaked from the cell. This indicated that a futile cycle for xylose may be operative under conditions of high xylose and may explain the facilitated diffusion kinetics observed. A semi-defined minimal medium for the growth of Clostridium thermohydrosulfuricum Rt8.B1 was developed in this study. This medium was able to support the growth of several thermophilic anaerobes. Most strains studied showed morphological changes. In one instance, spores were seen in an apparently nonsporulating strain of Thermoanaerobium brockii DSM 1457 which could not be attributed to a contaminant. This observation has resulted in the species being renamed Thermoanaerobacter brockii comb. nov. and the genus Thermoanaerobium being removed due to the removal of the type strain.
The fluvial biology of Lake Taupo rainbow trout
(The University of Waikato, 1991) Rosenau, Marvin Leslie; Chapman, M. Ann; Green, John D.; Swales, Steve
The riverine biology of adfluvial-lacustrine rainbow trout (Oncorhynchus mykiss, previously Salmo gairdneri) from the Waimarino, Tokaanu, and Hinemaiaia Rivers was investigated. These three streams are important spawning and rearing habitats for rainbow trout recruiting to an economically important sport fishery in Lake Taupo, New Zealand, yet each has very different bio-physical characteristics; the Waimarino River is an unregulated stream with seasonally varying flow and temperature regimes; the Hinemaiaia River is an hydro-electric flow-controlled stream having a seasonally varying temperature regime and daily flow fluctuations; the Tokaanu River is an unregulated groundwater-fed stream with stable flows and temperatures. Nutrient concentrations and spawning and rearing habitats also vary considerably among these streams. Scales were taken from adult rainbow trout from these streams and examined; they showed both widely-spaced outer, and narrowly-spaced inner, circulus zones. While there were no among-population differences in average circulus-spacing in the outer-growth zone, there were significant among-population differences in the inner zone; these two zones are suggested to represent (common) lake and natal stream rearing, respectively. The back-calculated minimum and average lengths at migration of juveniles from stream to lake was similar for all three populations (ca. 94 mm and ca. 140 mm, respectively) but there were significant among-population differences in age at emigration. The scale patterns and stream sampling suggested that most Hinemaiaia River rainbow trout left the river within the first year of growth (64%) whilst much higher proportions of juveniles surviving to adulthood in the other two streams overwintered before emigrating in their second year (up to 70%). Scales were also taken from juvenile rainbow trout captured from the Waimarino and Tokaanu Rivers. The patterns on these scales corresponded closely with the features seen on the inner-growth zone of the adult scales. This further strengthened the assertion that the inner-growth zone on the adult scales reflects a period of juvenile natal-stream growth before the fish go to Lake Taupo. The utilization of fluvial habitat by juvenile rainbow trout, common bullies and koaro in the Waimarino River was examined using minnow trapping as a methodology. There was segregation of habitat by these three species with regards to one or more of the following variables: 1) water depth, 2) water velocity, 3) substrate size, and 4) instream cover. Except in winter when the habitat choices by fingerlings (45-93 mm fork length) and smolts (>93 mm fork length) overlapped, there was also a segregation of habitat by the various size classes of juvenile trout, including fry (<45 mm fork length). Furthermore, there were ontogenetic trends and larger juvenile trout choose habitats with faster and deeper water and having substrates with larger diameters than did the smaller size classes of fish; larger juvenile trout were also more closely associated with instream cover. Woody and herbaceous cover were generally important for all species and size classes of fish in the Waimarino River. The distributions of juvenile trout and koaro and common bullies in the Waimarino, Tokaanu and Hinemaiaia Rivers was investigated. The species composition varied considerably among seasons, study sites and rivers. More bullies were found in the downstream reaches of these streams and this appeared to be positively related to water column depths and inversely related to velocities. There was a negative relationship between the catch rates of rainbow trout juveniles and koaro. The hydro-electric dam overflow channel on the Hinemaiaia River contained exceptional numbers of koaro. I also examined the inherited variability in parr mark numbers in juvenile rainbow trout from the Tokaanu and Waimarino Rivers. Ripe male and ovulated female trout were obtained from each of the study streams and reciprocal and pure crosses were made from the pooled gametes. The resulting juveniles were reared to fingerling size in separate tanks under similar conditions. The parr marks bisecting the lateral tine on the left side of the fish were counted and there were significant differences between the two pure crosses; the reciprocal hybrid crosses were intermediate in number. This suggests that there was a genetic difference controlling parr-mark number in these fish. The parr marks of wild-caught fingerling rainbow trout from the two study populations were also counted and there were no significant differences in number between these groups but the wild caught fish had intermediate numbers of parr marks compared to the laboratory fish. This suggests that either 1) there were genetic differences controlling parr-mark number between the laboratory and the wild fish with regards to the genetic control of parr mark number in these groups, or 2) population specific environmental influences (e.g., temperature) were modifying the parr-mark number of the genetically different wild juvenile trout, during their embryonic development in their respective natal streams, to produce a similar parr-mark number in these stocks of fish. Genetic differences in agonistic behaviour were also investigated in laboratory incubated juvenile rainbow trout from the Waimarino and Tokaanu Rivers. Because of the small sample sizes involved in this experiment, the results are considered to be only preliminary. However, if the observations reflect the behaviours in the wild populations, this genetic difference is likely to be adaptive and have evolved in response to the very different conditions in these two rearing streams. Finally, embryo and alevin development and survival rates were examined for fish from the Waimarino and Tokaanu Rivers. Two pure and two reciprocal-hybrid crosses were made and the resulting groups were incubated at the same time and under identical conditions at target temperatures of either 12 or 7°C. Within temperatures, the hatching date was the same for all crosses (12°C, 27 d; 7°C, 51 d). However, there were significant among-cross differences, within temperatures, with respect to emergence date; these differences were a result of phenotypic (egg size) and genotypic variability. Alevins from smaller eggs emerged earlier than equivalent crosses from larger eggs; alevins sired by Tokaanu River males emerged earlier than equivalent crosses of Waimarino River males. Samples of eggs were also taken ovulated rainbow trout from each population and the Tokaanu rainbow trout had lower egg weights at standard female lengths. These population differences in egg-size and rates of development are thought to be adaptive and to have evolved in response to conditions encountered by the incubating fish m their respective natal streams. The Tokaanu river has an inferior spawning environment, with lower intra-redd dissolved oxygen levels and poorer quality gravel; thus, selection has produced a population of rainbow trout having small eggs, fast developing alevins in order to maximize survival under adverse incubation conditions. Survival rates from fertilization to hatch in the experimental crosses were above 90% for all groups at both 7 and 12°C; however, embryos of larger eggs had slightly, but consistently, lower survival rates than embryos from smaller eggs, at both temperatures. Likewise, survival from hatch to emergence was also above 90% for all crosses at 12°C; however, there were substantial among cross differences in alevin survival rates at 7°C and this was the result of phenotypic (egg size) and genotypic (population) effects. These differences are also thought to be adaptive and appear to reflect selection resulting from water temperature differences that these alevins would normally encounter under natural conditions in their respective natal streams.
The immobilisation of Thermus strain Rt41A proteinase and its use in peptide synthesis
(The University of Waikato, 1991) Wilson, Shelley-Ann; Daniel, Roy M.; Peek, Keith
A proteinase isolated from Thermus strain Rt41A was purified to apparent homogeneity using ion exchange and FPLC chromatography and had a final specific activity of approximately 9000 azocasein units/mg. The substrate specificity of the proteinase against various peptide p-nitroanilide substrates was investigated and compared with the results of Peek (unpublished results) and Cowan et al. (1987b) Rt41A proteinase has a preference for aromatic amino acids in the P₁ site but, will also cleave the pNA group from peptides with leucine, arginine, alanine and lysine in this position. When utilising p-nitroanilide substrates the peptide must have a minimum of 3 amino acids for activity to be observed. Rt41A proteinase was immobilised to controlled pore glass (CPG) and Polymer Carrier Va-Epoxy Biosynth resin. The former of which was compared to the free proteinase. Both large (azocasein) and small (SucAAPFpNA) molecular weight substrates were utilised to measure the activity of the immobilised proteinase. Pore size of the CPG beads had little effect on % recovery of enzyme activity when it was added at a fixed level of activity/g of beads, whereas, it increased with increasing pore size when added at a fixed level/m² of support. Saturation of the CPG beads, with 105 nm pore size, was observed at 540 azocasein units/m². Lower levels (50 azocasein units/m² of 50 nm beads) were used in characterisation experiments. The specific activity of the immobilised proteinase was 5284 Au/mg with azocasein and 144 U/mg for SucAAPFpNA. The pH optimum of the immobilised Rt41A proteinase was 8.0 for azocasein and 9.5 for SucAAPFpNA compared to 10.5 for both substrates for the free enzyme. The immobilised enzyme retained approximately 65% of its maximum activity, against azocasein, at pH 12 whereas the free proteinase retained less than 10%. Stability towards pH increased on immobilisation, the greatest increase in half-life being approximately 12 fold at pH 7.0 at and 80 °C. Temperature activity profiles for both the free and immobilised enzymes were very similar when using either substrate. The stability of the immobilised proteinase however, was higher than that of the free enzyme in the presence and absence of CaCl₂ at various temperatures. Overall the results show that low levels of calcium (10 μM) protect against thermal denaturation, but that a high calcium concentration or immobilisation are required to protect against autolysis. Immobilisation of the proteinase also increased its stability towards two organic solvents, DMF and heptanol. Both the free and immobilised proteinase were utilised for peptide synthesis and the observed maximum yields were the same in both cases. A number of dipeptides were produced from amino acid esters and amides. The best acyl components, from those tested, were found to be Ac-Phe-OEt and Bz-Ala-OMe and Tyr-NH₂, Ala-NH₂, Trp-NH₂, Phe-NH₂, Leu-pNA and Val-pNA were all reactive nucleophiles. The substrate specificity for peptide synthesis was therefore very similar to that found for hydrolysis reactions. The synthesis of Bz-Ala-Tyr-NH2 was optimised by studying the effect of pH, temperature, solvent concentration, ionic strength and nucleophile and acyl donor concentration on the partition constant and the maximum yield. The initial conditions used were 25 mM Bz-Ala-OMe, 25 mM Tyr-NH₂, 70 °C, pH 8.0, and 10% v/v DMF. The optimised conditions were 80 mM Bz-Ala-OMe, 615 mM Tyr-NH₂, 40 °C, pH 10.0 and 90% v/v DMF; these conditions increased the maximum yield from 0.75% to 26% (% of original ester concentration). A number of cosolvents were also compared; the best peptide yields were observed with acetonitrile and ethyl acetate. Under optimised conditions acetonitrile gave similar yields (20%) as those observed in DMF except the acyl donor and nucleophile concentrations could be reduced to 25 mM and 100 mM respectively. The effect of different nucleophiles was also investigated with respect to peptide yield. Tyr- βNA and Tyr-pNA were found to be better nucleophiles than Tyr-NH₂. The yields observed were 48%, 61% and 8% respectively (90% v/v DMF, 40 °C, 25 mM Bz-Ala-OMe, 100 mM Tyr-X). No peptide was produced with Tyr-OBu as the nucleophile under the same conditions. With Ala in the P₁ position, and Tyr-pNA as the nucleophile, changing the blocking group or leaving group of the acyl donor had no effect on the peptide yield. Extending the length of the peptide of the acyl donor also had no effect. Peptide yields with Bz-Ala-OMe and Tyr-βNA in both DMF and acetonitrile was compared under optimised conditions. Quantitative yields were observed in DMF whereas only 26% yield was found in acetonitrile. Therefore acetonitrile, compared to DMF, increased peptide yields with the Tyr-NH₂ nucleophile, decreased yields with the Tyr-βNA nucleophile and it was also shown to have no affect on yields with the Tyr-pNA nucleophile.
A conceptual and psychometric examination of climate anxiety
(The University of Waikato, 2026) Gago, Tomás; Sargisson, Rebecca J.; Milfont, Taciano L.
Climate change stands as one of the most pressing crises threatening the world today, affecting natural environments, community resources and functioning, and individual’s health. As this crisis worsens, people are increasingly reporting experiencing negative affective reactions to climate change, even when they have not themselves been directly impacted by it. These various reactions, described under the umbrella term of “climate anxiety”, have been the focus of numerous studies, but the lack of a consistent definition and theory of climate anxiety has hindered scholars’ ability to integrate and build on the knowledge gained from these studies. My aim with this thesis is to contribute to this integration effort by articulating the various contributions from other scholars into a cohesive and holistic conceptualization of climate anxiety, and to examine how prevalent and adaptive this phenomenon is. Thus, the first study in my thesis (Chapter 3) is a metaanalysis of 25 studies examining the link between climate anxiety and psychological wellbeing. In this study, we found there was a strong association between these variables, whereby higher levels of climate anxiety were associated with lower levels of wellbeing. Given the consistent association between climate anxiety and psychological illbeing, in the next study (Chapter 4), we found that measures of climate anxiety capture this phenomenon differently to how measures of domain-free psychopathology capture their respective target constructs, by focusing more on affective reactions and less on somatic complaints. Additionally, we also found evidence supporting the convergence of the different climate anxiety measures, indicating they could be capturing the same underlying trait, and raising questions about the lack of parsimony in climate anxiety measuring. To address these concerns, in Chapter 5, we report a mixed-methods study where we developed a condensed climate anxiety measure with a wider representation of the various features associated with climate anxiety using Rasch modelling. Despite its wider content representation and ability to differentiate between high levels of climate anxiety, our measure did not predict wellbeing outcomes better than an existing eco-anxiety measure. Therefore, for the next study (Chapter 6), we used an established measure of climate anxiety to assess the prevalence of climate anxiety in New Zealand, finding that 1 in 20 New Zealanders report experiencing these affective reactions. Furthermore, we found that people who have been directly impacted by climate change, people with environment-dependent jobs, and those who did not feel prepared to handle climate change reported higher levels of climate anxiety. Lastly, we found that those with higher levels of climate anxiety also reported higher psychological distress and more engagement in pro-environmental behaviours. Altogether, this thesis contributes to the climate anxiety literature by providing a framework for the assessment of the various dimensions of climate anxiety and how they may be contributing to individual and planetary wellbeing. Moreover, the findings here may be used to raise awareness for the potential benefits and impairment associated with climate anxiety, and justify support for groups at increased risk of maladaptive climate anxiety.
Media, diaspora, and political engagement: Exploring the role of ethnic Chinese media in shaping Chinese New Zealanders' political participation in Aotearoa
(The University of Waikato, 2026) Zheng, Jiancheng; Hardy, Ann; Galikowski , Maria
This study investigates the intersection of Chinese-language media, 2020 New Zealand general election, and the lived experiences of the Chinese diaspora within New Zealand's dual bicultural and multicultural frameworks. As New Zealand's demographic composition grows more diverse, Chinese-language media have become vital in supporting cultural continuity and promoting political involvement within the Chinese community. This research emphasizes the distinctive role of the ethnic media—especially platforms like WeChat—in influencing the political behaviour, identity formation, and community dynamics of Chinese New Zealanders. Through the mixed research methods of the 2020 New Zealand general election, the study explores how the ethnic media shape voting patterns and political preferences, bridging critical language and access gaps for a community often sidelined within mainstream political discourse. Moreover, the study addresses the specific challenges faced by Chinese-language media, including financial constraints and censorship, and examines the broader impacts of information accessibility and media quality on democratic participation. The findings deepen the understanding of the Chinese diaspora's shifting role within New Zealand’s political landscape, reflecting wider global trends in diaspora media and minority political engagement. By positioning the experiences of Chinese New Zealanders within New Zealand's bicultural commitments and its multicultural realities, this research offers nuanced insights into the integration of the ethnic media in supporting a society's democratic infrastructure.
The interplay of the entrepreneurship ecosystem, collective entrepreneurship, and civic wealth creation in the tourism and agricultural sectors: A Sri Lankan perspective
(The University of Waikato, 2026) Gajanayaka, Channa; Pavlovich, Kathryn; Sinha, Paresha N.
Entrepreneurship research frequently treats entrepreneurship ecosystems, collective entrepreneurship, and civic wealth creation as parallel or pairwise explanations, leaving limited understanding of how these domains interact, generate reinforcing (or weakening) feedback, and co-evolve over time, particularly in emerging-economy contexts where institutional coordination is uneven and entrepreneurial practice is routinely shaped by shocks and livelihood insecurity. This thesis addresses that gap by developing the Triadic Synergy Model (TSM), an original, mechanism-based analytical lens that specifies reciprocal influence and feedback among Entrepreneurship Ecosystems (EE), Collective Entrepreneurship (CE), and Civic Wealth Creation (CWC), while conceptualizing Individualistic Entrepreneurship (IE) as a cross-cutting constraining practice logic that dampens triadic coupling. Empirically, the study adopts a qualitative multiple-case design focused on Sri Lanka’s tourism and agricultural sectors, drawing on semi-structured interviews with SME entrepreneurs, conducted primarily in participants’ mother tongue, with follow-up interviews and iterative thematic analysis and cross-case comparison to identify mechanisms, boundary conditions, and sectoral patterning. Findings show that CE is not a generic claim of “working together” but an achieved coordination capability: synergy emerges when participation is sustained and governance is credible. Under these conditions, CE enhances EE functioning by translating ecosystem supports into usable capacity (e.g., shared infrastructures, pooled learning routines, and collective voice) and can catalyze civic endowments when collective enterprise is organized around inclusion, stakeholder participation, and community capability building. EE is experienced less as a static set of “elements” than as workable access points (e.g., regulatory and procedural infrastructure, skills, finance, market channels, and shared resource pools) that condition day-to-day continuity and shape whether collective arrangements and civic pathways can persist. CWC is evidenced as multidimensional endowment creation and, in necessity-driven settings, as a survival and resilience pathway; however, civic wealth durability depends on participation infrastructures and credible support regimes rather than enterprise goodwill alone. Across the triad, boundary conditions are systematic: low trust, role ambiguity, opportunism concerns, politicization, and survival-first constraints weaken CE and narrow civic outcomes, interrupting the reinforcing loops the TSM specifies. By sector, tourism exhibits more consistent triadic reinforcement due to higher interdependence and more visible participation infrastructures, whereas agriculture shows stronger IE resistance, coordination fragility, and weaker feedback channels, yielding more constrained and discontinuous reinforcing pathways. By integrating Active Influence and Reactive Adaptation logics, the thesis advances a contingent, governance-sensitive explanation of when ecosystem supports translates into durable collective capability and when entrepreneurial activity produces civic wealth that consolidates over time in emerging-economy sectors.
Synthesis and kinetics of isomerisation of 2',6'-dihydroxychalcones
(The University of Waikato, 1987) Miles, Christopher O.; Main, Lyndsay
The first-order rate constant, kₒbₛ, for the chalcone - flavanone isomerisation has been determined over the pH range 0-14 in water (μ = 1.0 mol 1⁻¹ with KC1) at 30°C for the following 2' ,6'-dihydroxychalcones: 2' ,6'-dihydroxychalcone (34); 2' ,6'-dihydroxy-4-methoxychalcone (38); 2' ,6'-dihydroxy-3,4-dimethoxychalcone (40); 2' ,6'-dihydroxy-3,4,5-trimethoxychalcone (42); 2' ,6'-dihydroxy-2,4,6-trimethoxychalcone (44); 4-chloro-2' ,6'-dihydroxychalcone (46); 2' ,6'-dihydroxy- 4,4'-dimethoxychalcone (32); 2' ,6'-dihydroxy-3,4,4'-trimethoxychalcone (36); and 2' ,4,6'-trihydroxy-4'-rhamnoglucosyloxychalcone (naringin-chalcone) (48). The pH-rate profiles have been analysed in terms of contributions to cyclisation and ring opening of the various ionised chalcone and flavanone species, and individual rate and equilibrium constants for all the contributing reactions have been determined. Rate measurements with D₂O as the solvent (for 32, 34, 36, 38, 40, 42, 44, 46) revealed a large (presumably primary) hydrogen kinetic isotope effect for one of the contributing reactions, the cyclisation of the chalcone mono-anion. Enthalpies and entropies of activation for the mono-anion cyclisation have also been determined for chalcones 34, 36, 38, 42, 44, and 46. ¹H n.m.r. studies of the product from the cyclisation of the mono-anion in D₂O for two chalcones (34, 38) showed little preference in protonation at the 3-position of the flavanone. Mass spectrometry allowed measurement of the preference for protonation over deuteriation at the 3-position of the flavanone during cyclisation of the mono-anions of 32 and 38, under kinetically-controlled conditions in H₂O - D₂O mixtures. The data obtained were not in accord with the those from kinetic isotope effect measurements. The above results were considered in terms of possible mechanisms for the various reactions involved in the isomerisation. Factors contributing to the specially high rate of cyclisation of 2' ,6'-dihydroxychalcones as compared to simple 2'-hydroxychalcones, and to the high stability of the 5-hydroxyflavanones as compared to simple flavanones (relative to their isomeric chalcones) were also considered. The low stability of the 2' ,6'-dihydroxychalcones, compared to the 2'-hydroxychalcones (relative to their flavanones) was found to be due to a highly reactive mono-anion form combined with a lower first pKₐ, and a greatly reduced susceptibility of the flavanone anions to base-catalysed ring opening. By utilising the above kinetic results, new and improved syntheses of 2' ,6'-dihydroxychalcones have been developed in the face of what are shown to be unreliable literature reports. The following compounds have been synthesised and characterised for the first time: (32); (34); (36); (38); 5-hydroxy-4' -methoxyflavanone (39); (40); 5-hydroxy-3' ,4'-dimethoxyflavanone (41); (42); 5-hydroxy-3' ,4' ,5'-trimethoxyflavanone (43); (44); 5-hydroxy-2' ,4' ,6'-trimethoxyflavanone (45); (46); 5-hydroxy-4'-chloroflavanone (47): 6-benzyl-7-benzyloxy-5-hydroxyflavanone (68); 6-benzyl-5,7-dihydroxyflavanone (69); 2 '-hydroxy-6 '-tetrahydropyrany loxy-3, 4, 5-trimethoxychalcone (70); 3'-benzyl-4' ,6'-dibenzyloxy-2'-hydroxychalcone (72); 2' ,3,4' ,6'-tetrahydroxy- 4-methoxychalcone (86); 2'-hydroxy-4' ,6'-dimethoxy-3'-methylchalcone (93). Two new routes to 2' ,6'-dihydroxychalcones were developed. The first involved base-catalysed condensation of acetophenones and benzaldehydes with free phenolic groups protected as their tetrahydro-pyranyl ethers, followed by deprotection at pH 2. The second involved reaction of flavanones with chlorosilanes, in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, in which ring opening of the O-silylated flavanone was immediately followed by silylation of the resultant phenolate oxygen, thereby preventing recyclisation. The crystal structures of 5-hydroxy-4' ,7-dimethoxyflavanone (33) and 2' ,6'-dihydroxy-2,4,6-trimethoxychalcone (44) were determined by X-ray crystallography, 44 being the first 2' ,6'-dihydroxychalcone for which a crystal structure has been obtained. A computer programme was developed for the analysis of pH-rate data for 2'-hydroxy- and 2', 6'-dihydroxy-chalcones, but which is suitable for the analysis of pH-rate data for most mono- or di-acids in which the contributing reactions are (pseudo) first-order. The programme can also include second-order H⁺-catalysed reaction of the di-acid, and one second-order OH⁻-catalysed reaction, and calculates the concentrations of the various ionised species present on the basis that the two pKₐ values may not be well-separated. This programme has been used to successfully analyse the 2' ,4'-dihydroxychalcone - 7-hydroxyflavanone pH-rate profile previously reported, but not analysed, in the same way as for the 2' ,6'-dihydroxychalcones.
X-ray beam modelling in radiotherapy: the effect of lung inhomogeneities
(The University of Waikato, 1990) Metcalfe, Peter Edwin; Round, W. Howell
A lung phantom consisting of epoxy resin based analogs is developed in-house and a quality assurance method, which compares experimental CT numbers with theoretical CT numbers calculated from electronic cross sections, is described. Currently used photon beam inhomogeneity correction models and their inadequacies are discussed. The methods studied include Batho and Equivalent Tissue-Air-Ratio corrections. For a 10 MV high energy photon beam the mean difference in central axis depth dose in the lung phantom for these methods is 8.8% and 3.5%, respectively (for a 5 x 5 cm field). The differences in the beam profiles at an off-axis distance of 5 cm is 12.6% for both methods (for a 10 x 10 cm field). A unified three-dimensional superposition approach to dose calculations used in treatment planning of a polyenergetic 10 MV photon beam in radiotherapy is developed. This radiotherapy X-ray beam computation method involves an electron gamma shower (EGS) Monte Carlo generated surface polyenergetic dose spread array (PDSA), which describes the energy spread from a point interaction source. This is superposed with the relative reduction in polyenergetic total energy released per unit mass (TERMA) as the beam traverses tissue. By comparing primary PDSAs produced at different radiological depths, the effect of beam hardening on the PDSA has been quantified. Calculations show the mean electron range due to the surface 10 MV primary PDSA is 6.67 mm and the mean electron range of the beam hardened primary PDSA is 8.24 mm. In comparison a 3 MV primary monoenergetic dose spread array (MDSA) has a much smaller mean electron range of 4.81 mm. The effect of using a beam hardened PDSA for superposition is also studied. The mean percentage difference between depth dose curves obtained using superposition of a surface and a beam hardened PDSA is only 0.1 %. The mean percentage difference from experimental data for these superposition curves is 1.2% down to 20 cm in a homogeneous phantom. The superposition process is shown to be forgiving to spectral differences in the PDSA but sensitive to spectral changes in the TERMA. A method of scaling PDSAs to account for lung inhomogeneities is introduced which shows good agreement with experimental and Monte Carlo results in the lung phantom. The mean difference in central axis depth dose in the lung phantom for this method is 2.0% for a 5 x 5 cm field. The differences in lung for the beam profile at an off-axis distance of 5 cm is 4.3% for a 10 x 10 cm field.
The effect of voice input on information exchange in computer supported asynchronous group communication
(The University of Waikato, 1991) McQueen, Robert J.; Graham, Ian
Computer support for group communication in the business environment is examined. Study of group activities in videotaped business meetings identified information exchange as the most frequent communication task. Existing computer supported cooperative work (CSCW) systems for group communication are typically based on keyboard input, and this may limit their utility. A voice input prototype system for asynchronous (time separated transactions) group communication (AGC) with simulated conversion to text was developed and tested to determine if advantages over conventional keyboard input computer conferencing existed, and whether this method would have any effect on the information exchange task. An experiment utilizing 12 groups of 5 subjects compared the voice input prototype to an existing keyboard input computer conferencing system for an information exchange task, and over all test subjects, voice input resulted in an increase of the number of words contributed by 151 % and an increase in the information facts disclosed by 38%. For test subjects holding a high proportion of available facts, voice input resulted in increases of 204% in words and 39% for facts. Effective input speed was 150 words per minute for voice input. These results imply that for future asynchronous group communication systems supporting information exchange, incorporation of voice input capability, coupled with large vocabulary, connected word, speaker independent speech recognition should be considered.
The development of secondary education in New Zealand from 1935 to 1970
(The University of Waikato, 1989) Marshall, George Nairn; McLaren, Ian
This study traces the evolution of secondary education in New Zealand from 1935 to 1970, with special reference to questions of curriculum and control. Within the framework of contemporary social, political, and economic developments, it describes the transformation of a system comprising sixty-five schools offering a restricted, specialised curriculum to a mainly selected and limited clientele into one with 210 multilateral schools each catering for an entire age-range of pupils. Data were obtained from official documents and reports, journals, school histories and magazines, newspapers, and other published sources; from unpublished material, especially university theses; from interviews with prominent educationists of the period; and from personal observation and experience. Except for some reference to the Maori denominational boarding schools, the study is confined to state post-primary schools. It includes an examination of the literature related to the topic, and puts forward some theoretical considerations. In 1936, the newly-elected Labour Government set about promoting its ideal of providing equality of educational opportunity for all. However, the post-primary schools were slow to change, even though they were now enrolling increasing numbers of pupils for whom their existing curricula were totally unsuitable. The raising of the school leaving age to fifteen, the introduction of accrediting and the transferring of University Entrance to the sixth form, the release of the Thomas Report, and the inauguration of the new School Certificate all contributed to jolting the post-primary schools from their conservative stance. By the late 40’s, the system was contending with massive roll increases, completely inadequate facilities and resources, and a drastic shortage of teachers. No radical changes in educational policy occurred in the 50’s. The post-primary schools, continued with their struggle to adjust to the post-Thomas era, with its emphasis on catering for individual differences, advancing the social education of pupils, and encouraging greater pupil participation in school affairs. The decade also witnessed the emergence of post-primary teachers as a political force, a revival of the controversy over state aid to private schools, the beginnings of the demise of the technical high school, and the setting up of a Commission on Education in New Zealand to enquire into a wide range of educational issues. As well as ushering in the age of educational technology, the 60’s were characterised by constantly expanding pupil numbers, an increasing need for counselling services in the schools, persistent teacher shortages, the growth of teacher militancy, the rise of ‘pupils’ rights’ movements, the establishing of the Curriculum Development Unit, forward moves in rural education, the general acceptance of the concept of the comprehensive school, and the appearance of the first complete consolidation of the law on education since 1914. These events, trends, and issues provide the raw material of this thesis. Also, at four stages of the period under review, the study examines, in some detail, the policies, practices, and characteristics of the schools themselves, and attempts to present a picture of what it was like to be a principal, a teacher, or a pupil at a New Zealand post-primary school at that time.
Characterization of an extremely thermophilic, anaerobic sulphur-dependent archaebacterium
(The University of Waikato, 1991) Klages, Karin Ursula; Morgan, Hugh W.
The sulphur-dependent archaebacterial isolate ANI was studied in aspects of its ecology, physiology, and enzymology. Organisms closely resembling isolate ANI were enriched from New Zealand hot pools within a temperature range of 55-91°C and a pH range of 5.5- 9.0 and a sodium content above 0.5g/ℓ. The concentration of sodium ions was found to be a third parameter determining the presence or absence of these organisms. Isolate ANI is a neutrophilic, anaerobic extreme thermophile. In the laboratory, growth was observed within a pH range of pH 5.4 to 9.2 and a temperature range between 55 and 85°C. The organism is an obligate heterotroph with a requirement for peptone. In the presence of peptone, several amino acids, α-keto acids, glucose, lactose, casein, and starch stimulate growth. Sodium and sulphur are required for growth. Sodium can be replaced by lithium and sulphur by cystine and glutathione. Sodium is required for utilization of several amino acids and for synthesis of ATP. Presence of a Na⁺ gradient across the cytoplasmic membrane is essential for growth and ATP production. Ionophores affecting the Na⁺ gradient show a strong inhibitory effect, while a protonophore or a K⁺ ionophore exerted virtually no inhibition. In addition to a Na⁺ gradient the existence of either a H⁺ gradient or a membrane potential is required for growth and generation of ATP. The Na⁺ gradient is possibly generated via a Na⁺-translocating ATPase. Utilization of branched-chain amino acids in the presence of sulphur results in production of NH₄, CO₂, H₂, sulphide, and branched-chain fatty acids. When valine is utilized the major fatty acid end product is isobutyrate and with leucine or isoleucine it is isovalerate or 2-methylbutyrate (which could not be distinguished by analytical techniques used here). The metabolic pathway of branched-chain amino acids was investigated. The proposed common metabolic pathway for valine, leucine, and isoleucine involves four steps: deamination and production of the α-keto acid, oxidation of the α-keto acid and production of the acyl-CoA, production of the acyl phosphate from the acyl-CoA, and production of the fatty acid from the acyl phosphate, the latter step being coupled to production of ATP from ADP and inorganic phosphate. The presence of amino acid aminotransferase, α-keto acid oxidoreductase, and fatty acid kinase, which catalyze the first, second and fourth reaction respectively, was demonstrated in crude cell extracts, while the presence of phosphate acyltransferase, catalyzing the third step, was only suggested. Substrate-level phosphorylation is the major, if not the sole means of ATP generation in isolate ANI. Reducing equivalents generated by amino acid oxidation are transferred to a postulated hydrogenase and sulphur reductase respectively and sulphide and H₂ are produced. No inhibitory effect of H₂ could be demonstrated and reduction of sulphur as means for H₂ detoxification does not appear to occur in isolate ANI. Instead, H₂ and sulphide are produced concomitantly during growth. A type II restriction endonuclease of ANI, termed ‘ANi I’, was partially purified and its recognition sequence determined as CTAG. The cut site within the sequence is not known.
Management accounting and the social construction of reality
(The University of Waikato, 1990) Lawrence, Stewart R.; Gilling, Don; Bettison, David; Gilling, Margaret
One of the major problems of researching management accounting practice has been that of research practice. Traditional methods have not been able to yield insights into the richness and diversity of accounting practices in organisational processes. The perspective adopted in this thesis is that accounting practice is a symbolic and value-laden phenomenon that can only be understood in action. One way to understand accounting in action is to undertake a processual, interpretive study of an organisation and its development. The aim is to understand accounting practices where they have been developed and where they are used, as part of the ‘lived experience’ of organisational actors. The organisational setting for this study was that of a medium-sized English book publishing company. The distinctive culture that developed affects and is affected by accounting procedures. The way in which actors called upon and employed accounting procedures in their everyday projects, and the way in which these projects were understood and justified through accounting rationales, are described. The work of the management accountant is influenced both by the particular organisational setting and by the generally accepted constructs through which the professional accountant interprets the world. There is a tension between the rational and the social aspects of accounting practice. Those using accounting systems experience the systems’ inadequacies as purely technical-rational devices. The practice of accounting is actively involved in the regulation, even manipulation, of interpersonal relationships. Accountants have to transcend technique and necessarily become involved in organisational activities as cultural and moral agents. A movement away from a technical conception of management accounting towards a communicative function and understanding is suggested. Such a change in perspective would require an appreciation of the more general interpretive schemes, of which ‘accounting’ is a part, that actors use to understand their reality. It would involve an understanding of the partial nature of the accountants’ perspective and the effect that technical management accounting language and routines have on interpersonal relationships. The next generation of management accountants may regard such understanding as an essential characteristic of ‘practice’. Research using the interpretive approach could play a part in the creation of this new professional perspective.
Estimating and forecasting univariate and multivariate time series using dynamic linear models
(The University of Waikato, 1990) Bolstad, William M.; Foulds, Les R.; Turner, John; Hosking, Roger
This thesis investigates the place of dynamic linear models in time series analysis. These models, which are based on the state space representation of the time series where the dynamic parameters are the state variables, are particularly useful because they are applicable to non-stationary (as well as stationary) time series. In this thesis some forecasting algorithms using dynamic linear models are developed for univariate and multivariate time series, and the effectiveness of these algorithms is investigated. The algorithms are applied to some examples in biometrics and economics. The thesis is based on original research papers published hy the author, which are included as appendices 1-5. Chapter one surveys the field of time series analysis in order to get a broad overview of the subject. There are two main goals in time series analysis: the search for the underlying pattern in the time series, and the prediction of future values of the series. The first leads to the study of the time series in the frequency domain where a harmonic analysis of the time series decomposes it into a sum of sine waves at various frequencies. The second leads to the study of the time series in the time domain. Here the relationship between values a given distance apart is studied for each possible distance, and these relationships are used to predict future values. Chapter two develops the class of second order stationary stochastic processes in the frequency and time domains. The main tool of the frequency domain analysis, the spectral distribution of the process, and the main tool of the time domain analysis, the autocovariance function of the process, are seen to be Fourier transforms of each other. The effect of a time invariant linear filter on a second order stationary stochastic process is determined. It establishes the important results that if a stochastic process is Markovian, it must be the output of a first order linear system excited by Gaussian white noise. The Wiener-Hopf integral equation for the optimal (in terms of minimizing expected squared error) linear filter is developed using the principle of orthogonality. Chapter three introduces the state space representation of a linear dynamic system, develops the Kalman filter by using orthogonal projections, and establishes the recursive equations. Section 3 investigates the efficiency of the dynamic linear model applied to a linearly aggregated time series, and determines the efficiency of estimation using the aggregated time series relative to using the weighted sum of the component model estimators. While it is not surprising that the latter method is more efficient, the exact relative efficiency is developed here for the first time. Chapter four surveys the field of filtering in some non-Gaussian models. While the Kalman filter is still the optimal linear filter in the non-Gaussian case, it may be far from the optimal filter. Chapter five introduces multiprocess dynamic (regression) models to give a filter that is effective for short term forecasting in time series that are subject to abrupt, as well as evolutionary, changes in pattern, and may contain transients (outliers). In Section 3, the multivariate extension of the multiprocess dynamic linear model developed by the author is presented. The forecasting algorithm is used to forecast the quarterly inflation rate in the consumer price index, by using the inflation rates for the six main consumer price subindices, food, housing, household operations, apparel, transportation, and miscellaneous. This method was found to give an improvement over the univariate dynamic linear model forecasts, which in turn are improvements over the naive model forecasts. In Section 4, the biased perturbation multiprocess dynamic linear model developed by the author is presented and used to analyze growth hormone level data in young steers that are subject to dietary stress. The growth hormone level data exhibited the characteristics of pulsatile data, that is exponential decay towards a base level with occasional jumps in level when a pulse of growth hormone is released. The model was found to give an effective method of analyzing pulsatile data that can be implemented in real time. In Section 5, the multiprocess dynamic generalized linear model developed by the author is presented. It is shown to be an effective method for estimating a time varying population proportion. This thesis investigates dynamic linear time series models and has shown their place in the time series analysis framework. The relative efficiency of a dynamic linear model applied to a linearly aggregated time series has been determined. Estimation and forecasting algorithms based on dynamic linear time series models for univariate and multivariate time series have been developed and analyzed. They are effective for time series that contain outliers and exhibit occasional abrupt as well as evolutionary changes in pattern. These algorithms have been applied successfully to non-stationary time series in biology and economics.
The application of parallel processing to radiotherapy dose computation
(The University of Waikato, 1991) Murray, David Campbell; Round, W. Howell; Graham, Ian
Delivery of the correct dose to patients undergoing high-energy x-ray radiotherapy treatment for cancer requires accurate simulation of photon beams. Current algorithms using equivalent depth or tissue-air ratio (TAR) correction techniques fail to accurately model electron transport, and hence show inaccuracy in inhomogeneous regions of the body (especially at high photon energies). Newer techniques such as superposition and Monte Carlo simulation do model these effects, but require a large computational effort. Convolution in Fourier space is adequately fast using even standard microprocessor technology, but this approach lacks the flexibility offered by a density-scalable superposition kernel, available only in real space. However, in order for the real-space superposition algorithm to be clinically useful it is necessary to reduce planning times to acceptable levels. This has been achieved using a multicomputer system based on Inmos T800 transputer modules, where the superposition is calculated using a master/worker network employing synchronous message passing. The calculation is partitioned by decomposing the terma array into a number of command vectors or “grains.” The master task sends a vector to each worker task as it becomes free, and the worker performs the superposition for those interation voxels in the vector, storing the result in a local copy of the dose array. Upon completion of the entire calculation, the worker dose arrays are collected and summed to form the complete dose distribution. This approach has a very small communication overhead and exhibits near-linear speedup with increasing processor number. The superposition algorithm has been incorporated into the GRATIS Treatment Planning System developed at the University of North Carolina. This system, based on the Uɴɪx and X standards, has been installed on a Sun SPARCstation network, with the transputer network attached to the Sbus port of one SPARCstation. The treatment planning system can access the transputers from anywhere in the network, using Sun’s RPC (Remote Procedure Call) standard. Energy deposition kernels required by the superposition algorithm have been produced using the EGS4 Monte Carlo Code System (Stanford Linear Accelerator Center). The user code RTPEDK has been developed to generate spherically symmetric kernels, which are then interpolated by the treatment planning system to form cartesian kernels for use in superposition. Two other user codes, RTPCYL and RTPCART, have been developed to model more general radiotherapy problems based on cylindrical and cartesian scoring geometries, respectively.
The growth and development of American satire: 1630-1895
(The University of Waikato, 1990) Pilditch, Jan; Walker, Marshall; McKim, Anne M.; Arvidson, Ken
The American predilection for ‘soft satire’ is well known. From Benjamin Franklin onwards American satirists have demonstrated a tolerance for human frailty unthinkable in the satires of the great Augustans. This thesis traces the growth and development of American satire from its beginnings in the Colonial period to the end of the nineteenth century. The period encompasses both a change in the understanding of the word ‘satire’, and therefore the type of satire written, and a change in world view which inevitably influenced content. The approach is chronological and historical and follows the growth of American culture as it is manifested in the satires in terms of content, form and language. Early American satires, infused with religious language, imagery, and modes of thought, took their structure from the optimistic American Jeremiad, and asserted the possibility of an ‘ideal America’. This influenced later secular satires which asserted an ‘ideal America’ using a providential frame, forging a link between sacred and secular values. During the course of the American Revolution satirists incorporated essentially secular and humanistic values within the providential frame and continued to assert the possibility of an ‘ideal America’. The effect of the providential frame was twofold. It ensured, in God’s time, an eventual favourable outcome rendering the satires optimistic and therefore corrective rather than destructive. Secondly it allowed for the suppression of realistic detail which could threaten the stability of what was in effect a realistic ideal, an ‘ideal America’. As American millenialism gave way to the humanistic ideals of the enlightenment in American satire the essentially religious view of an ‘ideal America’ gave way to a humane and secular view. The providential frame was dropped and optimism came to depend upon human will. This rendered the value system of the satires unstable. Satire underwent a crisis of authority and Jacksonian democracy was accompanied by works in which the gross materialism of the mob depicted in the attack undermined the democratic ideals the satires asserted. This was accompanied by an increasing Americanization of language, character and content in satirical works which usurped the satiric persona of an authoritative ‘man of letters’ in favour, in some cases, of the man of no letters. The logical dilemma created by notions of a realistic ideal is apparent in satires written immediately before and after the Civil War, so that these satires demonstrate a tendency toward the ‘tragical satire’ seen in the Jacobean period. However, Puritan influence manifested itself elsewhere in American satire in the form of the exemplary figure which, typically journeys like Franklin, along the path to improvement. These figures, like the Providential frame, serve to forge a link between the ideal and therefore absolute, and the real. The figures travel a realistic rather than ideological landscape and in early satires invariably have their share of human faults. They are characterized by an ability to cling to the ideal despite all evidence to the contrary, or by an ability to learn moral and, in the post-Revolutionary satires, essentially Federalist values, including those of the ‘Men of Letters’ who founded the early Republic. In Twain’s Huckleberry Finn, this figure becomes wholly American. The moral growth of Huck in the course of the novel is well known, as are the realistic aspects of his character, but Huck is also intelligent. He demonstrates a facility with language which in earlier satires characterized the satiric persona. It is suggested that as the American absurd hero develops, that figure absorbs the characteristics of the authoritative satiric persona of the ‘man of letters’, creating satire from within, rather than beyond the text - in effect, a democratic satire.
Arginase from Bacillus caldovelox
(The University of Waikato, 1988) Patchett, Mark L.; Daniel, Roy M.; Morgan, Hugh W.
Nine Thermus strains, six thermophilic Bacillus species, six extremely thermophilic archaebacteria and other thermophilic bacteria were cultured in arginine-supplemented media and screened for arginase, arginine deiminase and arginine decarboxylase activity by a reversed-phase liquid chromatography method developed to detect these arginine-catabolizing enzymes in cell-free extracts. Thermus, Bacillus and Sulfolobus strains produced arginase, but arginine deiminase and arginine decarboxylase activities were only detected in two archaebacterial anaerobes and Clostridium thermohydrosulfuricum. Other enzymes of the arginase and arginine deiminase pathways were also present in these bacteria. Inducible arginases (EC 3.5.3.1) were purified from Bacillus caldovelox (DSM 411) and Thermus 4-1A (TRUCC 52) by (NH₄)₂SO₄ and protamine sulphate precipitations, DEAE Sepharose CL-6B ion exchange chromatography, Superose 12 GP-FPLC, Mono Q IE-FPLC and phenyl-Superose HI-FPLC. B. caldovelox arginase has a Mᵣ of ~176000 and a subunit Mᵣ of 32000, suggesting a hexameric subunit structure. It has an isoelectric point of 5.4, a pH optimum for activity of 9 (at 60°C in 0.1M CAPS/NaOH buffer) and requires a divalent cation for activity. The purified enzyme contains 1.2 Mn²⁺ ions and 0.17 Fe²⁺ ions per subunit and is activated ~30% by Mn²⁺. The enzyme has a Kₘ for arginine of 3.4mM at pH9 and 25mM at pH7 and hydrolyses L-canavanine at 4.7% and D-arginine and L-homoarginine at <1% of the rate seen for L-arginine. It is competitively inhibited by L-ornithine with a Kᵢ of 0.55mM at pH9 and 4.4mM at pH7 and has an E, of 46.3kJ/mole at pH9. The B. caldovelox arginase is thermostable with a half life of 105min at 95°C at pH7 in the presence of 0.5mM Mn²⁺ and 25mM aspartic acid. Mn²⁺ and chelating agents or proteins have a synergistic stabilizing effect and it is suggested that an excessive [Mn²⁺] causes inactivation in the absence of a chelating agent. The apoenzyme, prepared by chelation of metal ions at pH7 at 60°C or by incubation at pH4.4 at 20°C, retains its native oligomeric structure but is dissociated into subunits at pH2.5 at 20°C. The subunits reassociate at pH9.5 at 20°C in the absence of Mn²⁺ to form the native oligomer. The Thermus 4-1A arginase has a Mᵣ of ~167000 and a subunit Mᵣ of 33000. It has an isoelectric point of 5.1, a pH optimum of 9.3-9.8 and is activated by V0²⁺, Mn²⁺, Ni²⁺ and Cd²⁺ and less strongly by Co²⁺, Fe²⁺, Mo(III) and Mg²⁺. The purified enzyme contains 0.33 Mn²⁺ ions and 0.1 Fe²⁺ ions per subunit and has an Eₐ of 30.2kJ/mole at pH9.
Studies on sulfate-reducing bacteria which degrade fatty acids and on an obligately anaerobic agarolytic bacterium
(The University of Waikato, 1989) Rees, Gavin Nigel; Harfoot, C.G.; Morgan, Hugh W.
Five methods were used to isolate sulfate-reducing bacteria using palmitate as the enrichment substrate. (1) Standard enrichment procedures gave rise to pure cultures of Desulfovibrio sapovorans. (2) In enrichments which involved the continual transfer of sediment throughout the isolation, two rod-shaped strains were isolated in pure culture and designated strains HoPal and AmPal. These latter strains had a number of characteristics similar to D. sapovorans, but also varied from the general description by a number of characteristics. Determination of their DNA base composition is required for confirmation of their identification. (3) When pasteurized sediment was used in the enrichments with palmitate as the electron donor, a strain of Desulfotomaculum sapomendens was isolated. (4) When enrichments were carried out at 13°C, a sulfate-reducing bacterium was enriched and purified. This bacterium was identified as Desulfobacterium species. (5) A series of enrichments were carried out whereby an increasing dilution of mud was used as the source material. Tubes with mud from the lower dilutions gave rise to typical Desulfovibrio sapovorans. However, mud used at higher dilutions gave rise to Desulfobacterium species, suggesting that these organisms may be present in higher numbers. Enrichments were carried out using branched-chain fatty acids as the electron donor. Freshwater enrichments with isobutyrate and 2-methyl butyrate gave rise to Desulfotomaculum acetoxidans and Desulfovibrio sapovorans, designated Amib and Am2mb respectively. Estuarine enrichments with isobutyrate and 2-methylbutyrate gave rise to Desulfobacterium vacuolatum, designated Okib and a Desulfosarcina species designated Ok2mb. Enrichments from both freshwater and estuarine sources using isovalerate grew very slowly and were not purified in this study. Studies on the physiology of strain Okib showed it was able to oxidize a range of amino acids and keto acids including proline, branched-chain amino acids, 5-aminovalerate and keto isocaproate. It neither fermented amino acids nor carried out Stickland reactions with pairs of amino acids. During the course of isolating the sulfate-reducing bacteria in this study, an obligately anaerobic agarolytic bacterium was enriched in association with a Desulfovibrio species. The agarolytic bacterium was obtained in pure culture and designated 16AV. This is the first account of the degradation of agar by an obligate anaerobe. Strain 16AV grew only on agar, agarose, galactose and cellobiose producing ethanol, acetate, H₂ and CO₂. Strain 16AV probably represents a new species of the genus Acetivibrio.

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