1,502 results for 1990, Doctoral

  • Haematology and inflammation in infections of farmed red deer (Cervus elaphus)

    Cross, John Philip (1991)

    Doctoral thesis
    University of Otago

    xiii, 180, i, 39 leaves, [1] folded leaf :ill. (some col.) ; 30 cm. Includes bibliographical references. University of Otago department : Microbiology

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  • A comparison of the fate of elemental sulphur and sulphate sulphur based fertilizers in pasture soils : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University

    Phimsarn, Sathien (1991)

    Doctoral thesis
    Massey University

    Nitrogen fixation by legumes has a particular requirement for adequate soil sulphur status. Sulphur (S) is a mobile nutrient and is easily leached from aquic soil environments, therefore regular topdressing with S fertilizer is required to maintain legume vigor and pasture production in most New Zealand pasture soils. Escalating fertilizer costs have focused attention on the efficiency of use of S fertilizers, particularly superphosphate (SSP) and alternative elemental S (S0) based fertilizers less liable to leaching loss in this aquic environment. Field and glasshouse trials, using the resident clover/ryegrass sward on undisturbed soil cores (150 mm diameter, 100 mm depth) , were undertaken to determine the comparative short-term fate of SSP and different particle sizes of S0. Methods for manufacturing radioactively labelled (35s) fertilizers were developed. In addition, the effect of sheep dung on the short-term immobilization of soil and fertilizer S was also investigated. A simple computer simulation model explaining the observed transformation of soil sulphur and 35s labelled fertilizer was developed. Initially, the effect of sheep dung on the short-term immobilization of soil and fertilizer S was investigated. Very small amounts (about 2-5%) of plant (clover/ryegrass pasture) S and P, within 1 00 mm of the area surrounding the dung pellet, were derived from the dung. Under the experimental conditions that prevailed, dung S behaved as a slow release S form causing neither greater immobilization of soil or fertilizer S nor mineralization of soil organic S. It was concluded that the impact of dung return on short-term (< one year) S fertilizer fate need not be considered. An initial field trial comparing the fate of microfine S0 (< 0.010 mm) relative to sulphate-based SSP was undertaken on Tokomaru silt loam, a New Zealand yellow-grey earth (Fragiaqualf). The microfine S0 oxidized within 30 days of application but initially (up to 60 days) was slightly less effective than SSP in terms of plant uptake. Over longer periods of time (150 days) their performances were comparable. Final cumulative plant uptake at 150 days accounted for 13.6% of microfine S0 and 16.3% of the SSP-sulphate. The major transformation of 35s from microfine S0 and 35s belied gypsum In SSP to soil organic 35s forms occurred in the first 30 days after application. The organic 35s activity formed from 35s0 was twice that formed from sulphate-based fertilizer and was mainly carbon- bonded 35s in the top 33mm of the pasture soil profile. The amount of organic 35s remaining as carbon-bonded 35s decreased with soil depth and the reverse occurred for the estersulphate 35s. By 1 50 days, greater activity from the microfine 35s0 remained in the soil organics fraction than from the sulphate-35s fertilizer, indicating that more soil organicS reserves may be formed through the use of fine S0 fertilizer than from the sulphate-based fertilizer. This also indicated the advantage of using S0 in minimizing the S leaching losses in this aquic environment. An inverse dilution technique using an isotope injector developed at Massey University to uniformly label undisturbed soil cores with carrier-free 35so4= solution was used to measure the impact of S0 and sulphate-based fertilizers on the fate of soil S. Results were consistent with the labelled fertilizer technique and both techniques indicated rapid incorporation of 35s into soil organic S and that the carbon-bonded S formed was likely to be a subsequent source of mineralized S available to plants. Soil samples from the preliminary field study were used to evaluate soil preparation and extraction techniques. Soil sampling and preparation techniques were evaluated on the basis that an extract sampling the plant available S pool in soil should have the same 35s specific activity as plant growing on that soil. The average 35s specific activity in a calcium dihydrogen phosphate (CaP-S) (0.04 M) extract from a freeze-dried sample of the top 60 mm of a pasture soil was most closely related to the 35s specific activity of plants growing on that soil. CaP-S extracts from field-moist soil or 0.01 M CaCI2 extracts from field-moist or freeze-dried soils had higher specific activities than plants. lt was concluded that plants were able to extract soil S from soils which was not exchangeable with added 35so4= fertilizers during either the field experiment or extraction with 0.01 M CaCI2. The second series of field and glasshouse trials were conducted to investigate the fate of 35s labelled SSP, gypsum and S0 of varying particle sizes (0 . 1 50 m m) which had not oxidized, the major fate of fertilizer 35s, either under glasshouse or field conditions, was again in soil organic matter mostly formed in the top 33 mm of the soil. Applications of gypsum and SSP caused 35s to move to the 33-1 00 mm soil depths but there was no additional influence of P on the depth to which so4= was leached. A preliminary computer simulation model describing the fate of 35so4 =-s fertilizer was developed. The model provided a very accurate method of predicting plant uptake of S from both SSP fertilized and u nfertilized soil cores. The model also indicated that, at any particular soil depth, on average, actual rates of mineralizatio n a nd i m mobilization may exceed root uptake of S by 1.5 to 2 fold (mg S turned over per unit of S taken up by plants). The accuracy of the estimated turnover rate could not be validated because the model gave relatively inaccurate predictions of the measured movement and transformations of 35s tracer added to the soil as SSP. There was, however, relative similarity between the observed and predicted proportional distribution of 35s between soil and plant S forms. Such a distribution supported the concept of using root activity as a modifier of mineralization and immobilization rates in order to describe the extent of these processes at different soil depths. The study has emphasized the greater importance of the surface few millimeters of pasture soil in S transformations, important in the fate of fertilizer and pasture plant nutrition. There appears to be scope in manipulating S0 particle size to improve the efficiency of the S fertilizer used.

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  • The effect of water stress on water relations, carbon isotype discrimination, and shoot and root growth of sainfoin (Onobrychis viciifolia Scop.) and lucerne (Medicago sativa L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Department of Plant Science at Massey University

    Mir-Hosseini-Dehabadi, Seyed Reza (1994)

    Doctoral thesis
    Massey University

    Sainfoin (Onobrychis viciifolia Scop.) is a useful forage legume regarded as having drought resistant attributes. Also, it does not cause bloat in ruminants and is not sensitive to alfalfa weevil (Hypera postica. L). Although the physiological and morphological responses to water stress of lucerne (Medicago sativa L.) are well known the responses of sainfoin to water stress have not been fully studied. In this study the physiological and morphological responses of sainfoin to water stress were investigated, with lucerne used as a reference plant. The results of the indoor and outdoor studies showed sainfoin had useful characteristics for forage production in dry conditions. Relative to lucerne it had a lower yield, due to lower leaf area, lower stem number and poor regrowth. However, sainfoin responded to water stress at least as well as lucerne. Sainfoin had a higher root:shoot ratio and a lower specific leaf area ratio than lucerne, indicating a higher allocation of carbohydrate to the roots, and a lower leaf surface area for transpiration in sainfoin than for lucerne. Water stress decreased the yield of lucerne proportionally more than sainfoin mostly due to the greater reduction in the above ground dry weight of lucerne. The indoor study of root characteristics of sainfoin and lucerne in 1m tall tubes showed that in terms of root development sainfoin responded to water stress better than lucerne. Although sainfoin had equal root mass and root length to lucerne, the root distribution of sainfoin at below 0.6 m depths was greater than for lucerne. As water stress developed sainfoin roots grew below 0.6 m earlier than lucerne roots. Sainfoin had a higher root osmotic adjustment than lucerne and also maintained higher (less negative) leaf water potential than lucerne. The stomatal resistances (Rs) of sainfoin and lucerne were equal, but Rs was not distributed equally between adaxial and abaxial leaf surfaces. The Rs of the adaxial leaf surface of sainfoin was lower and more sensitive to water stress than the Rs of the abaxial leaf surface. The different Rs of the adaxial and abaxial leaf surfaces of sainfoin was partly due to the different stomatal frequencies of the respective surfaces. Comparison of sainfoin cultivars in a climate room showed that the water use efficiencies (WUE) of Remont, Fakir, Cotswold-Common, and Eski, were similar. Remont was more sensitive to water stress than the other three cultivars, and Eski produced a greater root length and mass than other cultivars. The growth of Eski was initially slower than that of the Remont in both the indoor and the outdoor studies. However, lucerne grew faster than all the sainfoin cultivars. Over three harvests in the field the yields of Eski and Remont were similar but lucerne out yielded both sainfoin cultivars. Sainfoin produced a greater proportion of its yield earlier than lucerne, whereas lucerne distributed its yield throughout the whole season, indicating that sainfoin is adapted to regions with precipitation in only winter and spring. The results of the carbon isotope discrimination (Δ) analysis for the indoor and outdoor studies showed Δ had a negative correlation with WUE, leaf water potential, osmotic potential, and stomatal resistance, but had a positive correlation with relative water content, turgor potential, transpiration rate, and photosynthetic rate. These correlations demonstrated the usefulness of this technique for evaluating the responses of plants to water stress. The stressed plants always had lower Δ than the control plants showing the higher WUE of stressed plants. The Δ of roots was higher than the Δ of the leaves suggesting that the growth of leaves occurred in conditions that were an average drier than for the growth of roots. This was supported by the lower (more negative) water potential of leaves than roots. The Δ of the roots below 0.6 m depth was higher than the Δ of roots above 0.1 m depth suggesting the roots above 0.1m grew under higher water stress than the roots below 0.6m depth. Over three harvests in the field the Δ of Eski and lucerne were similar and the Δ of Remont was higher than for Eski and lucerne. In conclusion, sainfoin was found to have several useful attributes for growth and survival in dry regions. Of the sainfoin cultivars examined Eski was the best adapted to water stress. Relative to lucerne, sainfoin yielded less, but had a similar water use efficiency, a shorter season of growth, a greater root: shoot ratio, deeper roots and better maintenance of leaf water potential under water stress.

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  • Studies towards the chemical synthesis of the 18 kDa antigenic protein from Mycobacterium leprae : a thesis presented in partial fulfilment of the requirements for the degree of Ph. D. in Chemistry at Massey University

    Love, Stephen George (1991)

    Doctoral thesis
    Massey University

    This thesis describes the solid phase synthesis of a series of peptides from the antigenic Mycobacterium leprae 18 kDa protein and the total synthesis of the 148 amino acid protein. The peptides were synthesised using an Applied Biosystems 430A Solid Phase Peptide Synthesiser usually modified by the removal of in-line filters to the reaction vessel to allow the synthesis of the peptides using programs evolved by S.B.H. Kent. The peptides were cleaved from the peptide resin using liquid HF and purified by reverse phase HPLC. The first series of peptides to be synthesised revolved around a monoclonal antibody binding site. These peptides were SLP-1, (101-115, RILASYQEGVLKLSI), SLP-2, (111-124, LKLSIPVAERAKPRK), SLP-3, (121-134, AKPRKISVDRGNNG) and SLP-4 (109-125 GVLKLSIPVAERAKPRK). The other peptides were synthesised as a series of overlapping 20 mers covering the entire 148 amino acid sequence. These peptides are SLP-5 (1-20, MLMRTDPFRELDRFAEQVLG), SLP-6 (16-35, EQVLGTS ARPAVMPMDAWRE), SLP-7 (31-50, DAWREGEFVVEFDLPGIKA), SLP-8 (46-65, PGIKADSLDIDIERNVVTVR), SLP-9 (61-80, VVTVRAERPGVDPDREMLAA), SLP-10 (76-95, EMLAAERPRGLFNRQLVLGE), SLP-11 (91-110, LVLGENLDTERIL ASYQEGV), SLP-12 (106-125, YQEGVLKLSIPVAERAKPRK), SLP-13 (121-140, AKPRKISVDRGNNGHQTINK) and SLP-14 (136-148, QTINKTAEHEIIDA). Two other peptides SLP-15 (101-125, RILASYQEGVLKLSIPVAERAKPRK) and SLP-16 (91-115, LVLGEIVLDTERILASVQEGVLKLSI) were also synthesised. The peptides were used in immunological studies that determined the location of the L-5 monoclonal antibody binding site and showed where T-cell stimulation sites are located on the 18 kDa protein in murine systems. The synthesis of larger 50 amino acid fragments of the 18 kDa protein, peptides SLP-17 (101-148), SLP-18 (50-100) and SLP 19 (1-50) was carried out in order to determine if it was possible to synthesise the total 18 kDa protein. These fragments were synthesised in a similar manner to the previous peptides. From the synthesis of these peptides it was decided that the total synthesis of the 148 amino acid protein was possible. The synthesis of the 18 kDa protein was carried out using Kent's protocols as a single step process. The synthesis was monitored up to the 100th amino acid by ninhydrin assay with no failed couplings detected. The coupling percentages for all of the amino acids was achieved by peptide resin sequencing where the average percentage couplings were shown to be 99.49% with an overall yield for the protein on the resin of 49%. After Lo-Hi HF cleavage purification of the protein was hampered by the formation of aggregated products which proved initially to be inseparable from the protein. By sequencing some partially purified protein it was shown that under certain cleavage conditions the benzyl ether side chain protecting group was present on the threonine amino acids at positions 5 and 21. A further treatment of the protein using a hard acid-soft base mechanism with trimethylsilyl trifluorosulphonate/thioanisole was used in these cases to remove the remaining benzyl protecting groups. An attempt to overcome the aggregation of the protein involved the addition of SDS to the HF cleavage vessel. After purification the protein showed no signs of the aggregation products. A 90 amino acid fragment removed during the course of the synthesis of the 18 kDa proteien was cleaved and dissolved in 6M guanidine.HCl. After gel filtration on a Sephadex G-50 column, preparative HPLC was carried out on the isolated protein peak. The protein was then gel filtered again on a Sephadex G-50 column using 6M guanidine.HCl which separated the aggregated product to give a pure 90 amino acid protein after dialysis. The full synthetic 18 kDa protein was purified in a similar manner to the 90 amino acid fragment with the second gel filtration being carried out using a Sephadex G-100 column or a Pharmacia Superose 12 column. This provided pure synthetic 18 kDa protein in an estimated 1.8 % yield or 47 mg from this synthesis of a final 2.46 g of protein resin based on the starting protein on the resin.

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  • The neotectonics of the Wellington and Ruahine faults between the Manawatu Gorge and Puketitiri, North Island, New Zealand : a thesis presented as partial fulfilment of the requirements for the degree of Doctor of Philosophy in Earth Science

    Hanson, Judith Ann (1998)

    Doctoral thesis
    Massey University

    The Wellington and Ruahine Faults are two major faults of the North Island Dextral Fault Belt which formed approximately 2.5ma in response to the obliquely subducting Pacific Plate beneath the east coast of the North Island. Plate rotation has increased over time causing faulting patterns to change throw direction and strike-slip activity to increase within the Hawkes Bay area. Earthquakes rupturing either the Wellington or Ruahine Faults represent a serious hazard for this area. The purpose of this study was to establish a record of paleoseismic activity on the Wellington and Ruahine Faults which would allow future estimates of likely fault behaviour to be made. Trenches were excavated across these faults in mainly swampy environments. Within these trenches are layers of earthquake debris, layers of peat and other terrestrial sediments which have been deformed by earthquake activity. The layers of peat were radiocarbon dated to give the approximate ages of underlying or overlying earthquake debris. In many areas through which the faults pass are terraces composed of gravel which has been washed down from the axial ranges composed of Torlesse greywacke. The ages of these terraces are known due to layers of dated volcanic ash preserved in cover beds and wood preserved within. Some of these terraces have been offset by the fault. Using the known age of these terraces and the distance that they are offset by the fault, it was possible to calculate rates of fault movement during late Quaternary time. Field observations of the Wellington and Ruahine Faults reveal that the faults do not deform the areas through which they pass but rather act in response to regional deformation (within these structurally different areas). During earthquake events large blocks of land are moved both horizontally and vertically. The rate and size of these events is dependent on the regional geology where the earthquake ruptures occur. These regions are described as follows from south to north. The first region lies between Kahuki and the Ohara Depression, this is an area of prevalent strike-slip with horizontal offset rates averaging 12mm/yr for the Wellington Fault which is high by world standards. In contrast the Ruahine Fault displays little evidence of late Quaternary movement. The second region encloses the Ohara Depression which has an east-west compressional vector. Here strain is transferred from the Wellington to the Ruahine Fault thereby lowering the horizontal offset rate for the Wellington Fault to a maximum of 4.7mm/yr. The third region lies between the Ngaruroro and Tutaekuri Rivers and is a region with a north-northeast compressional vector. Here a horizontal offset rate of 3.3mm/yr (for the Wellington Fault) was determined using offset Ohakean terrace rises. The most northern region lies between the Tutaekuri River and Napier-Taupo Highway is a zone of normal strike-slip faulting with a combined horizontal offset rate of 18mm/yr for the Wellington, Ruahine and Te Waka Faults. These regions correspond to proposed rupture segments for both Wellington and Ruahine Faults. This study provides a record of at least 12 Ms >6.5 earthquake events recorded on the Wellington Fault in the Kahuki-Dannevirke district, 9 of which occurred in the last 30,000 years. This is the longest record of earthquake events recorded within fault trenches in New Zealand. The last earthquake on the Wellington Fault took place c. 300 years ago between Kahuki and Dannevirke. The largest single offset found in the Kahuki-Dannevirke area is estimated to have been displaced by 12m horizontally and 1.8m vertically. The estimated magnitude for an earthquake occurring in this region is between Ms 7.4 and 7.8. An earthquake of this magnitude would cause major destruction to all nearby engineering structures and to buildings in the nearby cities of Palmerston North, Napier and Hastings. Earthquakes of this size are estimated to occur every c. 300 years for the Kahuki-Dannevirke area, every 300 to 500 years for the Ohara Depression and every 1000 years for the region between the Tutaekuri River and the Napier-Taupo Highway. Similar studies were conducted along the Ruahine Fault trace between the Ohara Depression and the Napier-Taupo Highway. Seismic activity in this area is estimated to produce a Ms 7.4 to 7.5 magnitude earthquake every 400 to 500 years. Horizontal offset is expected to be in the range of 3 to 5.5m. Dates for the last earthquake on the Ruahine Fault have not been determined but it is possible that there have been up to 4 earthquakes on this fault since 1850 yrs B.P. The Wellington and Ruahine Faults pass mainly through farmland, areas of forestry and the southern Ruahine Range. When an earthquake rupture event occurs it is possible that most farmhouses will escape major damage with little loss of life, providing they are not built on the fault or in the path of any possible landslides. However major disruption is to be expected to any engineering works close to the faults. Landslides may occur on over-steep slopes in and near the axial ranges and some major rivers may be dammed as a result. The larger magnitude earthquakes will produce severe shaking in the cities of Palmerston North, Napier and Hastings where substantial damage can be expected to occur, especially to those buildings that are built on reclaimed land or on alluvial soils prone to liquefaction.

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  • The role of career development in relation to the developmental contextual position of young people in New Zealand : considerations for policy development and career services in New Zealand secondary schools : thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education

    McIntyre, Diana J (1998)

    Doctoral thesis
    Massey University

    This is a study of young peoples' career development needs and awareness and the relationship to personal development at the interface of school provision and wider economic, political and educational change that impinge on those relationships. It is theoretically embedded within the developmental contextual position of adolescent development, but much of the study is concerned with generating a comprehensive data base to inform policy development and practice considerations in careers assistance in New Zealand secondary schools. It begins, therefore, with an overview of the analytical framework of developmental contextualism, and goes on to explore more fully the dimensions presumed to be operating in relation to the career development of New Zealand youth. In doing so, it contributes a multidisciplinarian perspective, the essence of which it is argued, is an integral and necessary consideration in the provision of a developmentally appropriate and socially accountable approach to careers services in secondary schools. An examination of senior secondary school students' career development characteristics and experiences to which schools are in a position to respond forms the central empirical study of the latter part of this thesis. School careers staff, parents' and students' believed that schools were important environments for young people's career exploration and development and that an integrated, comprehensive careers service was an acceptable responsibility of secondary schooling. The careers information bases in schools were considered to be well resourced. Other dimensions, including career education, career advice and career counselling were nominated the most crucial areas needed for improvement. Limited opportunity for professional development and training in careers work was considered by staff to be the greatest barrier toward the provision of developmentally appropriate careers assistance. Other barriers included limited time allocation for careers work, low status in the school and unclear specifications regarding the role of careers staff and career services. Parents did not feel adequately informed about the nature and role of careers assistance in schools and this was considered a hindrance toward constructive involvement with their childrens career development. For the majority of students concern around career-related issues represented the source of considerable anxiety in their life. Careers assistance was highly valued by these young people, with most expressing concern about access to good quality careers advice and careers counselling. Limited access to specialised assistance at the personal level was reflected by students self reports on measures of career development and personal coping resources. Generally, the young people reported that they had not engaged adequately in appropriate career planning activities; had few 'useful' career exploration experiences; possessed insufficient knowledge about the nature and requirements of the world of work or occupations; and were not particularly knowledgeable about what to consider in making career-related (including education, training and work) decisions. Statistically significant relationships were found between scores on indices of career development and scores on a measure of how students coped with career-related concerns. While most young people approached career problems constructively, those students who were less likely to have engaged in useful planning and exploration and who had limited knowledge of the world of work generally were more likely to approach career development concerns non-productively, such as worrying about what might happen or closing oneself off from the problem. Perhaps the most salient theme to emerge in this thesis is the conviction that the career development of young people is a social as well as a personal process. Both the individual and society have much to gain from the young person's capacity for realism and purpose concerning school and post-school pathways and ultimately in the possession of a beginning repertoire of personal resources to manage career transitions in future journeys during their adult years. Ultimately, the complex interaction of individuals and society in relation to career pathways demand school-based career services which are clearly defined in policy, operationalised in official documentation, adequately resourced in relation to personnel and training and properly integrated alongside existing school practices.

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  • Quantitative genetics of prostrateness and other related attributes in red clover (Trifolium pratense L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Breeding and Genetics, Department of Plant Genetics, Massey University, New Zealand

    Mirzaie-Nodoushan, Hossein (1993)

    Doctoral thesis
    Massey University

    Three major experiments were conducted to investigate quantitative genetic aspects of prostrateness and related attributes in red clover (Trifolium pratense L.) during the years 1991-1993. These were done on several red clover genotypes with prostrate growth habit, nodal rooting ability, and early flowering characteristics, together with several other genotypes from semierect and erect types. Three types of experiments were carried out: 1)Since genotype environment interaction is believed to be ubiquitous in affecting the performance of plants, a series of experiments were carried out in order to get general information on a range of red clover germplasm representative of the three distinct types of red clover. Twelve genotypes (four per type) were studied in a randomized complete block design with three replications at two sites for two successive years. Several techniques of univariate and multivariate analysis were applied in order to quantify and qualify the magnitude and pattern of the possible genotype-environment interaction effects. Phenotypic and genotypic correlation values were estimated for each year and type separately as well as for the whole data set in genotype-environment interaction experiment. As a result of GE interaction analysis, a large amount of genetic variation was found in the genotypes examined. Several attributes presented significant first and second order interaction effects. Multivariate discriminant analysis based on these effects revealed discriminant scores by which the contribution and importance of each attribute in the response of genotypes examined in the environments was studied. Cluster analysis revealed that each of the three red clover types have their own particular responses to the environment effect. Phenotypic and genotypic correlation patterns were different from year to year and type to type. Prostrate growth habit reduced dry matter yield through significant negative correlation with yield components. 2) One accession from each of the two extreme types, erect and prostrate, were examined using a hierarchical mating design to investigate their genetic structure and to obtain more detailed genetic information on a narrower germplasm. Nine random plants from each type were cloned and used as male parent. Each male parent was crossed to six different random plants as female parents, three from the same population and three from opposite population. In other words four sets of crosses, two intra- and two inter-population sets, were made. To evaluate the 108 progeny families produced, male groups were divided into six sets, each containing three male groups from the same type. Each set was examined in a randomized complete block design with three replications. Various genetic parameters including genetic variance components and heritability of several morphological attributes were estimated. The two plant populations examined by the mating design, presented different patterns of genetic variation. Although the prostrate population did not have much genetic variation, its additive genetic variance components were of more importance than dominant components. However, in the erect population, dominance components of variance were more important than additive. In inter-population crosses, additive components were more important than dominance components. Stem length, number of internodes, number of branches, and plant diameter presented high level of heterosis. Number of stems, plant height, and stem thickness presented fairly high hybrid depression (negative heterosis). Heritability broad sense and narrow sense were estimated in genotype-environment interaction experiment and hierarchical mating design. Heritability values in GE interaction experiment were different from the heritability broad sense values in hierarchical mating design for most of the attributes, indicating the influence of GE interaction effect. This difference was not noticeable in prostrateness. Heritability narrow sense estimated in hierarchical mating design varied from intra- to inter-population crosses. 3) Three sets of generation mean analysis were carried out to obtain the most detailed genetic information including function of genes, and number of genes controlling the attributes. To achieve these, three pairs of parent plants were used (one erect and one prostrate in each pair) to produce F1, F2, Bc1, and Bc2. Several attributes which were distinct enough in the two types so that it could be assumed that parent populations were nearly homozygous in opposite directions, were studied in these crosses. Three, six, and the best parsimonious models were presented for the studied attributes. Prostrateness and stem thickness were partially to completely dominant over erectness and stem thinness. Small leaf size was over-dominant over large leaf size. There were strong evidences for additive x additive non-allelic interaction for stem thickness, additive x dominance interaction for leaf size, and dominance x dominance interaction for prostrateness and leaf size. Nodal rooting ability, prostrateness, and stem thickness seemed to be controlled by a low number of genes, whereas leaf size seemed to be controlled by several genes.

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  • Studies of sap-transmissable viruses of flowering cherries : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at MasseyUniversity

    Everett, Kerry-Rae (1993)

    Doctoral thesis
    Massey University

    Six sap-transmitted viruses were identified during a study of 434 flowering cherry trees (Prunus serrulata Lindl. sensu lato) in the North Island of New Zealand. These included Prunus necrotic ringspot ilarvirus strain G (PNRSV -G), apple mosaic ilarvirus (ApMV), flowering cherry virus B (FCVB), strawberry latent ringspot virus (SLRV), prune dwarf ilarvirus (PDV) and flowering cherry virus I (FCVI). Of these, ApMV, FCVB, SLRV and FCVI were new records for this host. FCVB and FCVI are newly described viruses. The most common virus was PNRSV -G (30.6% ); the other viruses ranged in incidence from 1 0.2% (FCVB) to 0.5% (PDV). A further nine viruses were also detected by mechanical transmission, but were not characterized in this study. Repeated sampling of 30 flowering cherry trees during late winter and early spring showed that ELISA was more sensitive for detecting PNRSV -G infection of flowering cherries than sap-transmission. Three methods for purifying PNRSV -G isolates from flowering cherry were assessed and the best method was one that used ether as a clarification agent. Yields of 5.0 mg/1 00 g of tissue were obtained. An antiserum was produced to PNRSV-G in New Zealand white rabbits which had a titre in microprecipitin tests of 1/81 92. A 338 nucleotide cDNA clone was made to PNRSV-G which hybridised to RNA-3 in Northern analysis. FCVI had a narrow host range, quasi-isometric particles of c. 26 nm diam. morphologically similar to the particles of ilarviruses, some bullet shaped particles (also characteristic of ilarviruses), four RNA species of 3550, 2800, 2000 and 1 050 nucleotides, and a coat protein of Mr 30 000. These properties indicate that FCVI has affinities with the ilarvirus group, but it differs in host range and symptoms, physical characteristics and serological properties from other members of this group. FCVB infected both monocotyledons and dicotyledons, but had a limited host range. FCVB has four RNA species of 3900, 21 50, 1 800 and 800 nucleotides (estimated from denatured dsRNA). Partially purified preparations contained isometric particles about 24nm in diameter. When purified at pH 7.5 FCVB sedimented in sucrose gradients as three UV absorbing components and virus particles appeared to be swollen. At low pH (5.0 or 6.0) or at pH 7.5 with the addition of magnesium ions, FCVB sedimented as a single predominant UV absorbing component and virus particles were not swollen. One major protein band (Mr 1 9 300) was extracted from partially purified preparations. Based on these features, it is proposed that FCVB is a new member of the bromovirus group. However, serological interrelationships were not detected with antisera to three bromoviruses, brome mosaic virus, broad bean mottle virus and cowpea chlorotic mottle virus. SLRV was isolated from flowering cherry trees in close proximity to each other in Auckland, New Zealand. The virus was not isolated from any of 390 flowering cherry trees tested from four other regions in the North Island. The virus was identified by host range, particle morphology, RNA and protein content and by serology. This is the first record of SLRV in flowering cherry. The nucleotide sequence of the 3' -terminal 2427 nucleotides of SLRV RNA-2 were determined using cDNA clones. The sequence contains a single reading frame terminating at an ochre stop codon 552 nucleotides from a 3'-terminal poly(A) tract. The N-terminal sequences of the two SLRV coat proteins determined by Edman degradation indicated that the larger 43K protein had a N-terminal Gly and the smaller 27K protein was cleaved at a Ser/Gly bond. No homologies were found in amino acid sequences or nucleotide sequences to four comoviruses or six nepoviruses suggesting that SLRV should be placed in a separate plant virus group.

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  • The "manufacture" of news in the 1993 New Zealand general election : a thesis presented in partial fulfilment of the requirements for the degree of PhD in Human Resource Management at Massey University

    McGregor, Judith Helen (1995)

    Doctoral thesis
    Massey University

    The news media's role in general election campaigns in New Zealand remains mysterious because few indigenous research antecedents inform the debate about the democratic function of journalists reporting election campaigns. This study analyses the creation of news by reporters during the 1993 New Zealand general election campaign and examines the relationships between journalists, politicians and third party sources which impact on political communication. The analysis leads to a discussion of the role of the news media in reporting election news. The notions that news is created by journalists and through relationship between journalists, politicians and third party sources are central to the study. The concept that news is "manufactured" or socially constructed is explained in the introductory chapter and linked to theoretical perspectives in the literature review in Chapter Two. The two broad research questions which the study answers are: 1. how was the news manufactured during the 1993 New Zealand election campaign? 2. what does this mean for the "dialogue of democracy" (Taylor, 1992)? The manufacture of news is examined from three perspectives in the research. These can be called the "doing" perspective which employs action research methodology, the "watching" perspective which uses participant observation methodology and the "measuring" perspective utilising content analysis. The research notes the failure of "any particular holistic paradigm" to sweep the field of political communication and employs "ground-up paradigm building" by carving out broad research problem areas and examining them through the use of appropriate research methodologies (Bennett, 1993, p.182). The objectives of the action research project were twofold. First, to assist an individual political candidate contesting the election to develop systematic processes to use the news media to raise the candidate's profile. Second, to increase the level of understanding by the political candidate of news media processes and news concepts such as newsworthiness, candidate accessibility and news angles so she could utilise the knowledge to generate news and photographic opportunities. The findings revealed that the political candidate perceived that her level of understanding of news processes was enhanced through the action research. The study found, too, that a systematic process of source relationship was cultivated between the political candidate and journalist, which in principle enhanced the democratic function of the news media as a platform for political debate. The action research project, was, however, bound by the prevailing climate of political rhetoric with all its shortcomings. The participant observation methodology explored the nature of the contest between the triumvirate of political candidates as sources, journalists and third party sources such as "spin doctors". A second research question examined whether reporters seek to reassert their role in such a way as to influence the news when traditional journalistic autonomy is threatened. The findings showed a complex, shifting contest for control over knowledge and power in the making of news. This contest was characterised by features such as the increased sophistication of third party sources actively intervening in news processes, by strategic utilisation of "new" news formats by politicians and by journalists vigorously defending their status and enlarging their role. The impact of the findings on democratic journalism were examined using Golding's (1990) suggestion of a revival of the notion of citizenship, "to what degree and in what ways are people denied access to necessary information and imagery to allow full and equal participation in the social order?" (p.98). The third methodology, content analysis, tested Edelstein, Ito and Kepplinger's (1989) theory of news content using a cognitive construct, the problematic situation. The results confirmed a larger interpretive as opposed to purely descriptive role for metropolitan newspaper journalists reporting news in the 1993 general election campaign in New Zealand. Over 70% of election campaign issues in the period sampled were defined problematically and negatively with a high reliance on references to loss of value and conflict. The findings have implications for how political candidates could and should tailor their political messages. Overall the results taken together have fundamental implications for the "dialogue of democracy" (Taylor, 1992). They disclose a powerful dilemma about the manufacture of news in the 1993 New Zealand general election. The expanded influence of the news media has not been accompanied by a reassessment of what it is the news media should be doing in election campaign reportage. Reformative suggestions are made in the final chapter of the study and the implications for political journalism in a democracy are discussed.

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  • Accounting in hospital organisations in New Zealand : a qualitative study in the reform context of 1984-1994 : a thesis presented for the degree of Ph.D. in Management Systems at Massey University

    Dixon, Keith (1994)

    Doctoral thesis
    Massey University

    Most general hospitals in New Zealand operate as part of the public sector. Since 1984, that sector has been the subject of radical, government led reforms. The espoused theory of these reforms has been expounded in terms of improving efficiency and effectiveness, and increasing accountability (Boston, Martin, Pallot & Walsh, 1991; G. Scott & Gorringe, 1989). The outward effects of these reforms on the hospital system consist of organisational changes, including the creation of hospital enterprises; changes to the way organisations are financed, including the use of taxes to purchase hospital products delineated according to diagnosis related groups [DRGs]; and changes to their management structures with a policy of general management replacing triumvirate management. Inevitably, these official changes have led to social changes to the system in general, and to the situated practice of accounting (Chua, 1988). In this study, an attempt has been made to describe and interpret these changes in the hospital system context, and to shed some light on the way in which accounting has come to be practised within that context. The theoretical posture of the study is a blend of rational, structuralist perspectives, and natural, interactionist ones (Boland & Pondy, 1983; Roberts & Scapens, 1985; Silverman, 1985; Denzin, 1989b). Consistent with this posture, the study strategy of control and design is a version of analytic induction (Denzin, 1989b; Silverman, 1985). The strategy comprised three phases during which a rough notion of accounting in hospital organisations was transformed into a working interpretation; data were gathered and analysed; and a thesis was compiled. The latter comprises thick descriptions and thick interpretations (Denzin, 1989a, 1989b; Patton, 1990) of the hospital system context and the situated practice of accounting; and a theory-in-use (Argyris, 1990; Argyris & Schon, 1974) which provides "explanations in terms of conditions of possibility" (Miller, 1990, p. 329) of what has been occurring in the hospital system, and the role of this situated practice in these occurrences. Underlying the study methodology was the notion of crafting both the study design and the theory which the study aimed to discover. The data were obtained using methods associated with naturalistic inquiry during time spent in the field. The use of these methods was prompted by a dearth of research published in this area relating to New Zealand, the wide range of perspectives among people participating or interested in the organisations, and the enormity of the changes to the system. The data were accumulated triangulately (Denzin, 1989b) from among different kinds of participants working on hospital sites (e.g., doctors, charge nurses, other health professionals and hospital staff with managerial responsibilities), from interested parties off-site (e.g, people working in the Department of Health, regional health authorities and organisations outside of the hospital system), and from official documents and published academic literature. The main vehicle used in the field was the nonschedule standardised interview (Denzin, 1989b), and inquiries focused, in turn, on practices relating to the budget, cost data reports and the annual report. In addition, interviews of a more general and exploratory nature, and some questionnaires, were used in the preliminary stages of the study. The picture which emerges from the study comprises four aspects: (a) a hospital system subjected to macro-level disturbances that have caused a mixture of effects in terms of structures, processes, interactions and outcomes; (b) an emergence of accounting since the mid-1980s in multiple roles, which are reflective and constitutive of organisational and social practices developing in the system (Ansari & Euske, 1987; Boland & Pondy, 1983; Burchell, Clubb & Hopwood, 1985; Chua, 1995; Kelly & Pratt, 1992; Loft, 1986; Roberts & Scapens, 1985); (c) qualified success for the situated accounting practice in the role of a political force in converting hospitals to a more effective form of organisation (Mintzberg, 1991); and (d) accounting practice at a fork in the road ahead, one way leading to its contamination of hospitals by inappropriate forces and forms (Mintzberg, 1991) based on production management; and the other leading to its emergence as an important support in a hospital system founded on a more conjoint organisational configuration (W. R. Scott, 1982) in which professionals and managers apply their craft cooperatively for the joint and several benefit of patients. These findings have implications which policy makers, health professionals and the public are urged to evaluate.

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  • The role of the external consultant in facilitating enterprise development : a thesis presented in partial fulfilment of the requirements for the degree of Ph. D. in Human Resource Management at Massey University

    Massey, Claire (1999)

    Doctoral thesis
    Massey University

    Today's organisations are faced with increasingly difficult choices about appropriate development strategies and structures. At the same time they are supported by a growing literature on management and organisational performance. Judging by the recent average growth in the revenues of the major international consulting firms (which was 34% in the period between 1998 and 1999 according to Kennedy Information, 1999), it appears that it is increasingly likely for organisations to call in external consultants to assist the organisation's managers to select appropriate development strategies from the range of available choices. It may be argued that this situation means that consultants are caught in the grip of two opposing forces: There is the possibility of providing clients with a better outcome than ever before, based on the advances of management thinking that have occurred over the course of this century. At the same time, clients' beliefs that continual advancements in organisational success are possible are putting pressure on the consulting industry to achieve "quick fixes". Whilst striving to perform effectively, consultants are being driven towards providing formulaic responses to complex organisational problems. One of the possible consequences is that they may not be making full use of the available knowledge about organisations, management and the practice of consulting. A further difficulty is that although the literature on the practice of consulting is rich, the theoretical knowledge base for consultants is still regarded as being incomplete. This situation provided the context for the study, in which the researcher sought to describe the roles that can be taken by a consultant during an assignment, and to explore the relationship between roles and subsequent organisational outcomes. Against this background the researcher identified an initial point of interest: the organisation that is engaged upon a search for organisational improvement. The term used to describe this was enterprise development (ED), which was defined as a situation in which an organisation's managers employ a consultant to undertake a set of activities with the objective of achieving a positive organisational outcome of some kind. The implicit research question was whether external consultants have a role to play in ED, and if so, whether there are ways to maximise the positive outcomes of their involvement. The researcher selected action research as the most appropriate methodology for working on client assignments, which also provided an opportunity for those participating in the study to gain from the process. As a starting point the researcher and the consultant "research partners" developed an initial proposition; "that it is possible to identify the factors that influence consultancy outcomes by engaging in participatory research with individual consultants". This proposition was developed over the course of three research cycles, and a diagrammatic presentation of these cycles in relationship to the research question can be found in Chapter 1 (page 31). In the first research cycle, the researcher worked alongside each of the three research partners on a single client assignment. They developed the "intervention profile" (IP) as a way of assessing the assignment's potential for an effective outcome. At the end of the research cycle the researcher and the research partners concluded "that assessing a particular client assignment with the help of the IP will assist a consultant to make choices about appropriate intervention strategies". In the second research cycle the researcher and the research partners developed the IP further, formulating a list of intervention "conditions" that may exist for each of the intervention profiles, and applying this extended framework to a client assignment. They concluded that applying the framework effectively is limited by the consultant's capability. At this point they developed the second proposition; "that a tool for assessing consultants' strengths and weaknesses will assist them to plan a programme of professional development that will improve their practice of organisational consulting". In the third research cycle the researcher and the research partners focused on the consultant's capability. Working through the "consulting approaches assessment" (CAA), a tool designed specifically for this study, the research partners identified their own approach to the practice of consulting. They concluded with a final proposition: "given that the way consultants approach the consulting process is one of the critical success factors, a consulting development programme that assists consultants to develop an intervention profile, assess intervention conditions and develop intervention strategies in the context of their own consulting approach will improve their practice of organisational consulting". The evidence of the six cases undertaken in this study suggests that there is more than one role that consultants can take with a client organisation that can contribute to ED. It is also clear that there are ways of maximising the positive outcomes of consultancy interventions. Here the study makes two specific contributions to the knowledge on organisational consulting that currently exists. Firstly, the IP and the CAA are additions to the literature, which allow practising consultants to apply the extensive literature on management and organisation to client assignments. Secondly, the researcher presents a model for organisational consulting which explicitly identifies the three different levels that consultants need to consider when undertaking client interventions (conceptualisation, strategy and practice), and categorises the existing body of knowledge on consultancy in terms of these levels. These contributions have fundamental implications for the training and development of organisational consultants, and their application has the potential to improve their value to the organisations that employ them.

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  • Effects of temperature on seasonal changes in growth and carbohydrate physiology of asparagus (Asparagus officinalis L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctorate of Philosophy in Plant Science at Massey University

    Hughes, Avis Rosalie (1992)

    Doctoral thesis
    Massey University

    In a temperate climate, most of the visible, seasonal changes in asparagus growth are induced by or dependent on changing temperature regimes. Senescence of ferns in autumn occurred below 13C, but was prevented by 20C. Crowns required chilling at temperatures below 12.5C to release the internal dormancy which occurred during winter. Although budbreak was never completely suppressed, the minimum temperature at which budbreak could occur changed during winter dormancy. Budbreak did not occur at 12.5C in some cultivars at maximum dormancy. The optimum temperature for the growth of young plants was between 25C and 30C. A model was developed which simulated seasonal changes in carbohydrate accumulation and utilisation, and the changing source-sink relationships within male and female plants. The model used temperature, indirectly, to determine the times at which seasonal changes in plant growth occurred. The basic unit for carbohydrate production and allocation in cultivars with well defined rhizomes, e.g.'Rutger's Beacon', was a rhizome and it's attached developing axillaries. An axillary rhizome became independent very soon after it had developed fern. The basic unit may differ in cultivars such as 'UC157' which have less well defined rhizomes. The strength of correlative inhibition within a cultivar appears to affect both rhizome morphology and budbreak patterns during spear harvest. In summer, young fern had a higher mobilising ability for assimilate than older fern or roots in male plants. In late summer-early autumn, roots became a stronger sink than the fern. On female plants, reproductive sinks (i.e, berries) had the highest competitive and mobilising ability. Crown carbohydrate concentration appeared to reach a physiological maximum of 65% in late summer. Most of the carbohydrate pool was long chain fructans, i.e, with degree of polymerisation above eight. The size of the crown carbohydrate pool increased during autumn and senescence as crown dry weight increased. The concentration of disaccharide increased during senescence indicating that it may have a role in cold tolerance. There was little change in crown dry weight or carbohydrate concentration of chilled plants until after the plants had been chilled for five weeks and the minimum temperature for budbreak had decreased. Respiration then increased as internal dormancy was further released. Changes in the composition of carbohydrate reserves are associated with the chilling process, and may affect the release of internal dormancy. Dormant plants required exposure to temperatures below 12.5C to increase the monosaccharide concentration above 4.5% dry weight and to depolymerise long chain fructans. Both these factors would decrease the substrate for some energy requiring process which must occur before budbreak can occur. 'Rutger's Beacon' required approximately 500 chilling units (calculated using the Utah model) to release 50% of the basal buds from internal dormancy and permit growth at 12.5C. The chilling response curve for asparagus appears to be flatter than the Utah model. This thesis confirmed earlier work which indicated that improved agronomic performance may be related to increased partitioning into carbohydrate storage tissue i.e, the crown. Genotypic differences in depth of internal dormancy and spear growth rate will also affect yield. Differences in carbohydrate metabolism are not the reason for agronomic differences between male and female plants. The strong sink effect of berries on female plants reduces crown dry weight and thus the crown carbohydrate pool.

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  • Synthesis and characterisation of poly(acrylic acid) microspheres containing β-cyclodextrin

    Bibby, David C. (1999)

    Doctoral thesis
    University of Otago

    xviii, 160 leaves :ill. ; 30 cm. Includes bibliographical references. "February 1999"

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  • Expectations and satisfaction in tourism : an exploratory study into measuring satisfaction

    Gnoth, Juergen (1994)

    Doctoral thesis
    University of Otago

    xi, 277 leaves :ill. ; 30 cm. Includes bibliographical references. University of Otago department: Marketing.

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  • Molecular cloning of cDNA encoding alliinase from onion (Allium cepa L.)

    Clark, Sonya A. (1993)

    Doctoral thesis
    University of Canterbury Library

    Alliinase catalyses the release of a range of volatile sulphur compounds which are responsible for the distinctive flavour and odour of Allium species. Clones encoding this vacuolar enzyme were isolated by immunoscreening a cDNA expression library constructed in the vector λZAPII with mRNA extracted from sprouting A. cepa bulb shoots. Six clones were characterized by DNA sequencing. Four of the cDNA sequences (Alli6, 7, 8B and 9) were found to be identical apart from variation in the length of their 5' ends. These sequences contained three putative polyadenylation signals. A fifth clone, Alli4B, was also very similar but displayed a truncated 3' end with six divergent bases just prior to the polyadenylate tail and lacked the most 3' polyadenylation signal present within the sequences of the other clones. It was evident from these differences that the clones were unique. However, their high sequence homology suggested they were encoded by a single gene, or two that are very closely related. The sixth clone sequenced, Alli4A, showed no homology to the other five clones, nor to any sequences within the GenBank database. The five highly homologous cDNA sequences ranged in length from 1604 bp to 1757 bp, and all appeared to contain a complete longest open reading frame encoding a polypeptide with a predicted size of 54 884 Da. Four peptide sequences derived from purified A. cepa alliinase were aligned, and showed 93% homology with the corresponding amino acid sequences deduced from the cDNA clones. Alignment of the native alliinase N-terminal peptide to the cDNA-inferred protein sequence predicted a hydrophobic 34-residue prepeptide sequence terminating in a peptidase cleavage site. Given the vacuolar location of this enzyme, it is probable that this region functions in targeting of the alliinase precursor to the endoplasmic reticulum. The inferred mature alliinase subunit polypeptide contained sequence motifs compatible with both Asn-linked glycosylation and pyridoxal phosphate cofactor binding. Conversion of clones to the phagemid form allowed the protein expressed in Escherichia coli from Alli6 to be western blotted. This analysis revealed protein moieties with molecular masses of 47 and 41.4 kDa. Southern hybridization analysis of A. cepa genomic DNA using an alliinase cDNA probe demonstrated the presence of a small multigene family with at least four members. Further genomic DNA hybridization analysis using a probe encompassing the 3' untranslated region of the alliinase clones demonstrated that the highest identity was to a single fragment, suggesting some alliinase gene family members may be transcriptionally inactive in sprouting bulb shoot tissue. A 1.7 kb transcript was detected by northern analysis of RNA extracted from developing A. cepa seedlings, indicating that the cDNA clones were near-full-length. Alliinase mRNA could be easily detected in seedlings up to 14 days after germination. Visual assessment and densitometer analysis of hybridization intensities suggested that alliinase transcripts were most abundant two to six days after germination and declined rapidly over the ensuing eight days. This indicated that alliinase expression is regulated at the transcriptional level during this period.

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  • Isolation and characterisation of genomic clones of alliinase from Allium cepa L.

    Gilpin, Brent John (1995)

    Doctoral thesis
    University of Canterbury Library

    The culinary and medicinal attributes of Alliums are derived from the high levels of nonprotein sulfur compounds which they contain. When onion cells are disrupted, the vacuolar enzyme alliinase hydrolyses the cytoplasmic S-alk(en)yl cysteine sulfoxide flavour precursors to produce pyruvate, ammonia and the many volatile sulphur compounds associated with flavour and odour. cDNA clones of alliinase have been previously isolated by immunoscreening an onion cDNA expression library. In this thesis, a genomic library of A. cepa was constructed and screened using the alliinase cDNA clone as a probe. Positively hybridising clones were screened initially using alliinase specific primers. Sequencing of PCR products, intact lambda and plasmid clones was performed to determine the sequence of the clones. One of the clones isolated encoded the previously isolated cDNA clones, while another contained a number of nucleotide differences. Both clones contained four small introns within the coding region. The predicted proteins of each clone are very similar, but nucleotide differences within the upstream, downstream, intron and mRNA regions may influence gene expression. An alliinase promoter from one of the genomic clones was cloned adjacent to a β-glucuronidase gene to determine the promoter functionality. These constructs were used for Agrobacterium mediated transformation of tobacco, and microprojectile bombardment of onion mini-bulbs. In tobacco, the alliinase promoter was expressed to a limited extent in some vascular tissue. Expression in onion minibulbs, although only evaluated transiently, indicated that this is a functional monocotyledonous promoter, which may have many applications in the genetic manipulation of onions. The expression level of the alliinase promoter was approximately half that of CaMV 35S promoter suggesting that features of the mRNA and protein are mainly responsible for the high expression level of alliinase.

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  • The ecological role of bryophytes in alpine streams of New Zealand.

    Suren, Alastair M. (1990)

    Doctoral thesis
    University of Canterbury Library

    The ecological roles of aquatic bryophytes in 2 small New Zealand alpine streams were investigated. The streams differed with respect to algal biomass and detrital inputs, reflecting their location either above the tree-line (Mouse Stream) or flowing through mountain beech forest (Tim's Creek). Streambed instability was also higher in the forested site. Quantitative sampling of bryophytes and riffles over 18 months revealed the existence of discrete macroinvertebrate (>250 µm) and meiofaunal (i.e., 5% of bryophyte material in their guts. The cranefly Limonia hudsoni was the only taxa that appeared to graze bryophytes extensively. Lack of consumption may be related to that fact that bryophytes contained more refractory, and less "digestible" material than selected riparian vegetation, or to the presence of antiherbivore compounds within some species. The importance of bryophytes in affecting energy inputs into streams was finally examined. Algal biomass was higher on structures mimicking bryophytes than stones, and biomass was higher above the tree-line than below. Natural bryophytes trapped more FPOM than riffles, and mimics at Tim's Creek trapped more FPOM than at Mouse Stream. Bryophyte biomass at both sites however was similar, reflecting the ability of these plants to tolerate a wide range of light regimes. Retention of introduced organic matter into streams was influenced by bryophytes, whereby streams with these plants retained material better than streams without.

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  • A photometric and spectroscopic study of selected southern, chromospherically active stars.

    Watson, Lyndon (1999)

    Doctoral thesis
    University of Canterbury Library

    The results of a combined photometric and high-resolution spectroscopic study of southern active-chromosphere stars selected from the ROSAT Bright Source Catalogue are presented. The star CS Ceti (HD 6628) is shown to be a single-lined spectroscopic binary and an orbital solution derived from radial-velocity measurements is presented. Evidence that one of the stars is an F-type dwarf and the other a highly active G-type subgiant is presented, together with information on the apparently asynchronous rotation of the latter and the spatial origin of its Hα emission. The system BB Sculptoris (HD 9770) is shown to include a chromo spherically active eclipsing binary of the BY Dra class and evidence that this is the star previously known as HD 9770B is presented. A precise orbital period is presented. Further evidence is presented to show that the star known as HD 9770A is also a binary system, one member of which dominates the absorption spectrum of BB Scl. Two further stars selected from the Bright Source Catalogue are recommended for further study: HD 147633 in which a known binary system is found to contain a further chromospherically active, short-period, double-lined spectroscopic binary; and HD 222259, a known chromospherically active binary in the light curve of which a spot wave which persists on a time scale of years has been found and for which a precise period is presented. In addition, the results of a continuing program of observation of the chromospherically active system GT Muscae (HR4492) are presented. Evidence is presented that the known eclipsing binary system HD 101380 consists of A0 V and A0/2 V stars, and the period of the system is further refined. A combined photometric and high-resolution spectroscopic study of the active binary HD 101379 provides evidence that its active star is a late G-type bright giant rather than a K4 star as suggested in a previous study. Evidence that the source of its Ha emission lies in the space between the stars is discussed. High-resolution spectra of two chromospherically active stars - CF Tucanae (HD 5303) and HD 219025 - observed for other programs are also presented and briefly discussed.

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  • Noise limits due to light mixing in optical code-division multiple-access systems.

    Smith, Elwyn D. J. (1998)

    Doctoral thesis
    University of Canterbury Library

    This thesis is concerned with the performance limits arising in optical code-division multiple-access (OCDMA) networks due to the mixing of light from the independent sources of each user. The scheme of spectral-amplitude OCDMA is shown here to be significantly limited by the phase-induced intensity noise arising from such mixing, and the corresponding signal-to- noise ratio and network capacity limits are of the same order as those arising in coherence-multiplexing systems, also due to such noise. Mixing can only occur between spatially coherent light, and this typically takes place through the combination of the signals into a single-mode fibre. The use of multimode fibre instead of single-mode can thus significantly reduce the levels and effects of phase-induced intensity noise, and this is experimentally demonstrated. It is shown that in general, assuming independent sources, there are only four possible ways in which to alleviate or eliminate noise limits of the form found for spectral-amplitude OCDMA. These are to separate the signals from each user in either the temporal, spectral, or spatial domains, or else to coherently despread the received signal. Neither spectral separation nor coherent de spreading are practical for spectral-amplitude OCDMA, but spatial separation via multimode fibre may be applied. The use of pulse-position modulation (PPM) with spectral-amplitude OCDMA is shown to be able to improve the performance beyond the limits found earlier, and this is because of the temporal separation it introduces. However, unlike the direct reduction of source duty cycle, PPM signalling can be applied without increasing, relative to the bit rate, the modulation or detection bandwidths, nor the dispersion sensitivity. Such PPM signalling and the associated decoding can also be applied to other similarly limited systems, including those based upon coherence multiplexing. If an OCDMA system is incoherent, has independent sources of the same spectrum, and has only a single-mode fibre to and from each user, then it can only avoid the significant noise limits found for spectral-amplitude OCDMA by the temporal separation of the signals from each user. This is the case for incoherent unipolar OCDMA systems, since the sparse codes of these systems rely on such temporal separation. Bipolar codes are not sparse, and in bipolar systems there is ordinarily no significant temporal separation between the signals from each user. Consequently, assuming sole single-mode-fibre paths and independent sources with identical spectra, every incoherent bipolar OCDMA system must encounter performance limits at least as bad as those found for spectral-amplitude OCDMA. These worst-case limits are identified for each of the incoherent bipolar OCDMA proposals to date.

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  • Biochemistry of fruit colour in apples (Malus pumila Mill.).

    Lister, Carolyn Elizabeth (1994)

    Doctoral thesis
    University of Canterbury Library

    Apple fruit display a wide range of colours from green and yellow through to an array of red shades. The biochemical basis of colour differences in apples was investigated with a particular focus on the flavonoids. Three main groups of flavonoids were found: anthocyanins, flavonols and proanthocyanidins. Apples contained predominantly 3',4'-hydroxylated flavonoids (e.g. cyanidin and quercetin glycosides) with only small amounts of 3'- (e.g. kaempferol glycosides and phloridzin) and 3',4',5'-hydroxylated compounds (e.g. (+)-gallocatechin). Galactosides were generally the predominant flavonoid glycosides and the pattern of glycosylation was a result of either the substrate specificity or the levels of specific glycosyltransferases. Pigment composition was determined for a number of New Zealand-grown apple genotypes and Malus species and differences in flavonoids were found to be quantitative and not qualitative. In addition, there were large differences in the concentrations of chlorophyll and carotenoids. Changes in pigment composition, and the activities of three enzymes of the flavonoid biosynthetic pathway (PAL, CHI and GT) were measured during the development of red and non-red apple fruit. The composition of the flavonoids in red and non-red cultivars was similar except that the red cultivar synthesized cyaniding glycosides during ripening. There were significant quantitative changes in all pigment groups during ripening but there were no significant qualitative changes in flavonoids. There was coordinate regulation of the flavonoid enzymes, including PAL, during both developmental regulation and UV induction of flavonoid biosynthesis. Changes in enzyme activities generally correlated with changes in flavonoid concentration, particularly during ripening, although none of these enzymes appeared to be the rate-limiting step(s) in flavonoid biosynthesis. PAL-IS did not have a significant effect in controlling the changes occurring in flavonoid biosynthesis. Differences in accumulation rates of flavonoids in the two cultivars investigated in detail were a function of the levels of enzyme activity. The colour of an apple fruit was determined by a number of factors. A major control point was one of the final steps in the flavonoid pathway (conversion of leucocyanidin to cyanidin) resulting in the synthesis, or lack of synthesis, of the anthocyanins. In all apple genotypes and cultivars examined the genes encoding for the enzymes responsible for catalysing this step must have been present, but the control was at the level of expression. Copigmentation is the bonding between anthocyanins and other phenolic molecules resulting in stabilization of the anthocyanin in its coloured form, a bathochromic shift and an increase in the absorbance of the visible band. In apples copigmentation probably had a role in stabilising anthocyanin colouration but did not influence colour variation because it was a constant factor. Self copigmentation may be occurring in some cultivars with high anthocyanin levels, resulting in blueing of the red colour. The intensity of the red colour was a function of the energy requirement for pigment synthesis, vacuolar size, pigment distribution and the influence of environmental factors. The major differences in hue were more likely to be due to the visual blending of chlorophyll, carotenoids and anthocyanins. Thus, the final appearance of the fruit was the result of the initial pigment concentrations plus the combined changes and hence the resultant final concentration of all three pigment groups (flavonoids, carotenoids and chlorophyll). The biochemical basis for fruit colour variation in apples has been determined but there are still some gaps in our knowledge particularly the control of flavonoid biosynthesis. The prospects for future genetic manipulation of apple fruit colour are discussed.

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