14,226 results for Doctoral

  • Malignant lymphomas in sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University

    Johnstone, Alastair Campbell (1974)

    Doctoral thesis
    Massey University

    Malignant lymphoma is the general term applied to any neoplastic disorder of lymphoid tissue, including Hodgkin's disease and reticulum cell sarcoma. This group of neoplasms are among the most commonly occurring spontaneous neoplasms of sheep in New Zealand, being exceeded in frequency only by carcinomas of the small intestine and primary neoplasms of the liver. It has not been established whether malignant lymphoma is of sporadic or enzootic occurrence in this country, but from limited epidemiological observations in which on two occasions the disease was seen in two animals from the same property, it is possible that the latter distribution occurs. This and most other series indicate that mature sheep are most frequently affected but the disease does occur in younger sheep and lambs. A study has been made of the pathology of ovine malignant lymphoma, based on 22 cases, most of which were collected from slaughter-houses and histological material from a further 18 cases filed previously at this laboratory. In nearly all cases nodular or diffuse lesions, consisting of accumulations of invasive neoplastic cells of lymphoid origin, were distributed widely throughout the body. Gross evidence of tumour in the lymph nodes was present in all except three cases of the disease. This involvement was usually multiple, with many of the carcass and visceral lymph nodes containing tumours. The spleen contained neoplastic lesions in 73 per cent. of the cases examined. Of the non-lymphoid organs affected by malignant lymphoma, the liver, kidney, bone marrow, heart, small intestine and abomasum predominated. Of the 40 cases examined, 37 were classified as lymphosarcomas and three as reticulum cell sarcomas. The degree of cellular differentiation in the lymphosarcomas varied from primitive lymphoblastoid to well differentiated lymphocytic cell types, with the less differentiated forms being more common. Some nuclear and cytoplasmic abnormalities which have previously been described as being non-specific in other types of neoplasms were seen in specimens from 10 cases which were examined with an electron microscope. Support for the hypothesis that "malignant lymphoma of sheep is transmissible" was sought by attempts to experimentally transmit this disease to lambs using intraperitoneal injections of cell-free tumour extracts during gestation or within 12 hr of birth. To date none of these sheep, which are only three years old, have developed overt neoplasia but 20 of them have developed elevated numbers of circulating lymphocytes. This has persisted for periods of two years or more and there is evidence to indicate that this should be interpreted as a preclinical phase of malignant lymphoma. To investigate an hypothesis that malignant lymphoma of sheep is due to infection by an oncorna virus, electron microscopic examinations were made on specimens from fresh tumour as well as on preparations from tissue cultures which had been inoculated with various ovine lymphoid tumour homogenates. These studies were inconclusive and it was not until cultures of phytohaemagglutinin-stimulated lymphocytes derived from the sheep with experimentally transmitted lymphocytosis were examined that virus-like particles, consistent with the morphology of "type-A" oncorna viruses could be demonstrated. They were present in membrane-limited vacuoles and cytoplasm of these cells and less frequently extra-cellularly in the five experimentally inoculated sheep examined but were not present in any of the lymphocytes from an equal number of control sheep. Lymphocyte cultures from 15 of the experimentally inoculated sheep showed sensitization to antigens in ovine malignant lymphoma homogenates when tested by a macrophage migration inhibition test. This test also demonstrated the presence of common tumour specific antigens in five of the six tumour extracts used either for sheep inoculations or in testing for macrophage inhibitory factor production. In an attempt to accelerate the development of overt neoplasia in three of the experimentally inoculated animals showing a persistent lymphocytosis, they were given a combined course of the immunosuppressive agents azathioprine and horse anti-sheep lymphocyte globulin. This resulted in a profound fall in circulating lymphocytes and while the cell mediated immunity was suppressed, as judged by the survival of skin allografts, macrophage migration inhibition in response to tumour antigens was not significantly altered in two of the three animals under treatment. A close relationship was demonstrated in the experimentally inoculated sheep between the occurrence of lymphocytosis, the development of tumour specific cell mediated immunity and the presence of virus-like particles in phytohaemagglutinin-stimulated lymphocytes. This evidence combined with the demonstration of common apparently tumour specific antigens in malignant lymphoma extracts used in these studies provides strong support for the hypothesis"that this disease of sheep is transmissible and is most probably due to an infection with an oncogenic virus". The exploitation of the sheep model described is of potential value for the comparative study of preneoplastic events in the general field of cancer research.

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  • Behaviour of emulsion gels in the human mouth and simulated gastrointestinal tract : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatu, New Zealand

    Guo, Qing (2015)

    Doctoral thesis
    Massey University

    Food structure greatly impacts the digestion process of food in the human body. Food structure design is a potential strategy to modulate food digestion and develop foods with controlled nutrient digestion and release. This research aimed to understand the dynamic processes of digestion of whey protein emulsion gels from the mouth to the intestine. Therefore, a series of heat-set whey protein emulsion gels, the structure of which was designed by varying NaCl concentration (10, 25, 100 and 200 mM) and oil droplet size (1, 6 and 12 µm), were formed. Mechanical properties in linear viscoelastic region, large deformation and fracture region and microstructure of gels were evaluated. In vivo oral processing and in vitro oral-to-gastrointestinal digestion of whey protein emulsion gels with different structures were investigated with a focus on the effect of gel structure on the gel disintegration and lipid digestion. Results showed that the gel strength increased with increasing NaCl concentration. At the micro-scale, the gel structure became from homogenous to porous with increasing NaCl concentration from 10 to 200 mM. The fragmentation degree of whey protein emulsion gels in the mouth showed a positive linear relationship with the gel strength (i.e. a higher gel strength, the greater gel fragmentation degree). During oral processing, the small oil droplets (~ 0.45 µm) incorporated in the protein matrix were stable without oil droplet release. During gastric digestion, the bolus of the gel containing 10 mM NaCl (soft gel) disintegrated much faster than that of the gel containing 200 mM NaCl (hard gel) in the human gastric simulator (HGS). The disintegration of the soft gel in the HGS was caused by both the abrasion and fragmentation while the abrasion was the predominant mechanism of the disintegration of the hard gel. The larger particle size of the soft gel bolus slowed down the emptying of gels from the HGS. With continued digestion, the emptying of both gels from the HGS was accelerated by gel disintegration. The gel structure greatly influenced the gel disintegration at the micro-scale. The soft gel particles were gradually disrupted into individual oil droplets, with the protein matrix dissolving after gastric digestion for 4 hours while the hard gel particles still retained the oil droplets inside the protein matrix. The colloidal structure of emptied gastric digesta, which generated from original gel structure, still significantly impacted the digestion of whey protein emulsion gels in an in vitro intestinal model. In general, the colloidal structure of the emptied gastric digesta of the hard gel hindered the breakdown of gel particles and hydrolysis of oil droplets more effectively than that of the soft gel. The remaining structure within the hard gel particles limited the free motion of oil droplets, which led to a lower degree of coalescence and breakup of oil droplets. Interestingly, coalescence appeared to occur between neighboring oil droplets inside the emptied gastric digesta of the hard gel during intestinal digestion. The structure of the gels containing 100 mM NaCl became from aggregated particle to emulsion-filled with increasing oil droplet size from 1 to 12 µm. The gel strength also decreased with the increase of droplet size. For the gels containing large oil droplets (6 and 12 µm), oil droplets were released from the protein matrix along with some coalescence during oral processing. During gastric digestion, a higher degree of coalescence of oil droplets occurred and coalesced oil droplets creamed to form a top oil layer. This slowed down the emptying of gels from the HGS. For the gels containing 1 µm oil droplets, most oil droplets still retained in the protein matrix during oral and gastric digestion with minimal instability of oil droplets. In addition, increasing interactions between oil droplets and protein matrix by decreasing oil droplet size hindered the protein hydrolysis. Overall, this research provides an understanding of the way in which food disintegrates in the human body and highlights the role of food structure on the digestion of food in the human body. These findings could assist in designing the functional new foods that deliver health benefits (e.g. lipid regulation, encapsulation and release of nutrients) and improving human health related to food digestion (e.g. dysphagia, dyspepsia).

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  • Estimating the public health risk associated with drinking water in New Zealand : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Masey University

    Phiri, Bernard Joakim (2015)

    Doctoral thesis
    Massey University

    This thesis is concerned with the application of both epidemiological and molecular tools to assess the drinking water safety in New Zealand. Compromised drinking water safety is commonly manifested as gastrointestinal illness. The studies in this thesis were motivated by the desire to nd ways of reducing the burden of such illness in the human population. Although the studies were conducted in the New Zealand setting the methodologies can be readily applied elsewhere. The rst study investigated the factors associated with the presence of microbes in raw water intended for public consumption. Random forest, an established non-parametric statistical method, was used to model data with possible complex interactions and identi ed variables that were predictive of the presence of microbes in raw drinking water. E. coli, which is widely used as a microbial contamination indicator in the water industry, was found to be a better predictor of the presence/absence of Campylobacter (bacteria) than protozoan microbes (Cryptosporidium and Giardia). This suggests that alternative methods of determining the presence/absence of pathogens in water should be developed. In the second study, the relationship between river ow and reports of cases of gastrointestinal illness was described using the distributed lag modelling approach. This revealed a positive relationship that peaked around 10 days after high ow. Further, the river ow-gastrointestinal illness relationship was stronger in small drinking distribution networks than in large ones. The small drinking water distribution networks could be targetted for facility upgrade in order to enhance their ability to deliver microbiologically safer drinking water. The third study utilised culture-dependent methods to assess the public health risk associated with drinking water supplied at outdoor recreation facilities | campgrounds. Water treatment using methods such as ultra violet and chemical treatment were found to be highly bene cial for the campgrounds to deliver drinking water that was microbiologically safe and compliant with water safety regulations. The pro les and functional factors of drinking water microbial communities are described in the fourth study. Techniques from the fast-growing eld of metagenomics were employed for this purpose. The capability of metagenomic techniques to detect multiple pathogens in a single assay was demonstrated. This has the potential to greatly enhance the speci city and sensitivity of microbial water quality testing.

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  • Effects of postharvest treatments on sweetpotato (Ipomoea batatas) storage quality : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, New Zealand

    Pankomera, Pilirani (2015)

    Doctoral thesis
    Massey University

    After harvest, sweetpotato (Ipomoea batatas) storage root quality is reduced due to weight loss, sprouting and rots. There are also hidden quality losses relating to loss of nutritional compounds. In order to maintain sweetpotato quality during storage, sweetpotatoes need to be stored at 13 - 15 °C and 80 - 90% RH. However, controlled temperature methods are difficult to achieve for subsistence farmers in less developed countries who have limited access to electric power. This work was undertaken to determine the potential postharvest techniques that would extend sweetpotato storage life without compromising phytochemical concentration. Postharvest treatments investigated in this work were hot water dipping (with or without coating) and ethylene (with or without 1-MCP) treatments. The work was undertaken using mainly ‘Owairaka Red’ and ‘Clone 1820’ sweetpotato cultivars. Following treatments, these sweetpotatoes were stored at 25 °C and 80 - 90% RH for 4 to 12 weeks. Hot water dipping (HWD) at 51 °C for 11 min delayed sprout growth by 2 weeks but increased weight loss. Coating (carnauba wax 5%) significantly reduced weight loss, but increased sprout growth in ‘Owairaka Red’. A combination of HWD and coating was effective in reducing both sprout growth and weight loss. ß-carotene content measured in ‘Clone 1820’ ranged from 17.3 to 25.6 mg/100 g dry weight. The concentration was not affected by HWD or coating, but declined by about 30% during 12 weeks storage. The calculated retinol activity equivalent (RAE) ranged from 363 to 537 RAE, per 100 g of edible portion of sweetpotato. Based on the recommended daily intake for vitamin A, a serve of 100 g would supply more than 25% of daily retinol requirement for all age groups, suggesting that even after storage ‘Clone 1820’ is a good source of vitamin A. In addition, no treatment adversely affected the phenolic acid and anthocyanin concentrations. Roots that were HWD showed a subtle increase in total phenolic content, phenolic acids and anthocyanin concentration when compared to control roots, but the effect was shortlived. Previous studies have demonstrated that ethylene is a potential sprout inhibitor, but causes darkening of flesh colour and the development of off-flavours after cooking. Ethylene-induced responses may be inhibited by 1-methylcyclopropene (1-MCP). 1- MCP and ethylene combined effects on sweetpotato physiological, flesh colour and phytochemical variables were assessed during storage. Ethylene treatment with or without 1-MCP inhibited sprout growth, increased root respiration rates by 2-fold, and caused root stem-end split leading to high weight loss and rots. Ethylene treatments also caused flesh darkening, and this was not prevented by a single 1- MCP (1 µL L-1) pre-storage treatment. When roots stored in continuous ethylene were subjected to multiple 1-MCP (1 µL L-1) treatments, the ethylene-induced root splitting and flesh darkening were delayed/reduced whilst maintaining minimal sprout growth. This implies that ethylene-induced negative responses in sweetpotato can be mitigated with on-going 1-MCP treatment. The sensory results showed that roots stored in air were highly preferred by consumers over roots stored in ethylene; nevertheless, acceptance means scores of all treatments were above five, indicating that ethylene-induced flesh darkening was not severe enough to cause consumer rejection. Based on these findings, it is proposed that a combination of HWD and coatings can be used to extend non-refrigerated storage life of sweetpotato with no major effect on phytochemical content. The results on ethylene are consistent with previous findings that ethylene suppresses sprout elongation. However, the associated negative effects outweigh the benefits of using ethylene as a sprout control. Future research therefore should focus on finding ways to get the benefit of ethylene for sprout reduction without incurring risk of root splitting.

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  • Formalist features determining the tempo and mode of evolution in Pseudomonas fluorescens SBW25 : a thesis submitted in partial fulfilment of the requirements for the degree of Ph.D. in Evolutionary Genetics at Massey University, Auckland, New Zealand

    Farr, Andrew David (2015)

    Doctoral thesis
    Massey University

    In order to explain the adaptive process, it is necessary to understand the generation of heritable phenotypic variation. For much of the history of evolutionary biology, the production of phenotypic variation was believed to be unbiased, and adaptation the primary outcome of selection acting on randomly generated variation (mutation). While true, ‘internal’ features of organisms may also play a role by increasing the rate of mutation at specific loci, or rendering certain genes better able to translate mutation into phenotypic variation. This thesis, using a bacterial model system, demonstrates how these internal features – localised mutation rates and genetic architectures – can influence the production of phenotypic variation. Previous work involving the bacterium Pseudomonas fluorescens SBW25 has shown that mutations at three loci, wsp, aws and mws, can cause the adaptive wrinkly spreader (WS) phenotype. For each locus, the causal mutations are primarily in negative regulators of di-guanylate cyclase (DGC) activity, which readily convert mutation into the WS phenotype. Mutations causing WS at other loci were predicted to arise, but to do so with less frequent types of mutation. The data presented in this thesis confirms this prediction. My work began with the identification and characterisation of a single rare WS-causing mutation: an in-frame deletion that generates a translational fusion of genes fadA and fwsR. The fusion couples a DGC (encoded by fwsR) to a membrane-spanning domain (encoded by fadA) causing relocalisation of the DGC to the cell membrane and the WS phenotype. This is one of the few examples of adaptation caused by gene fusion and protein relocation in a realtime evolution experiment. I next took an experimental evolution approach to isolate further rare WS types and characterized these, revealing a range of rarely taken mutational pathways to WS. Lastly, I describe an example of extreme molecular parallelism, in which a cell chaining phenotype is caused – without exception – by a single nucleotide substitution within the gene nlpD, despite multiple mutational pathways to this phenotype. Characterisation of different nlpD mutants suggests this molecular parallelism is caused by a high local mutation rate, possibly related to the initiation of transcription within this gene.

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  • Interaction between sulfur (S) and nitrogen (N) assimilation pathways in response to S and N supply in onion (Allium cepa L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Molecular Biology at Massey University, Palmerston North, New Zealand.

    Joshi, Srishti (2014)

    Doctoral thesis
    Massey University

    This thesis investigates the extent of interdependency between the sulfur (S) and nitrogen (N) assimilation pathways in the commercially important, S-accumulating, monocot species, onion CUDH2107 (Allium cepa L.), to elucidate some of the regulatory points of cross-talk between these two pathways. To test the interactions between the two pathways, a factorial S x N depletion experiment was set up. Plants were grown in short day conditions to maintain the pre-bulbing stage after which they were transferred to long day conditions to promote bulbing. At the end of the short day conditions, the plants were harvested as leaf, pseudo stem and root and at the end of the long day conditions, as leaf, bulb and roots, for each of the four treatments. The four treatments comprised of control treatment (designated C; comprising 14 mM N and 2 mM S), low S treatment (designated –S; comprising 14 mM N and 0.25 mM S), low N treatment (designated –N; comprising 3.5 mM N, 2 mM S) and coupled low S and N treatment (designated –S-N; comprising 0.25 mM S and 3.5 mM N). In terms of changes in biomass, both the root and the shoot biomass tended to be higher under the –S treatment at the bulbing stage, although these changes were only significant for the root biomass. Under the – N and the –S-N treatments, the shoot biomass was much lower when compared with the control plants at both the pre-bulbing and the bulbing stage, although no change in the root biomass was observed. The exception was at the bulbing stage under the –S-N treatment where the root biomass was significantly higher when compared with the control plants. At the transcriptional level in response to the -S treatment, the relative transcript abundance of commonly used S-starvation marker genes, AcHAST1;1LIKE1 and AcAPSR1 increased in both root and the leaf tissue and was more marked at bulbing. In contrast, transcript abundance of AcAPSK1, which marks a bifurcation in the S-assimilation pathway, decreased. At bulbing, a decrease in the relative transcript abundance of AcATPS1, AcSIR1 and AcOASTL3 in the leaf tissue and AcATPS1, AcAPSK1, AcOASTL2, AcNRT2;1LIKE1 and AcNiR1 in the root tissue was observed in response to the –S treatment. However, in response to N deprivation, under the –N as well as –S-N treatment, the transcript abundance of AcHAST1;1LIKE1 and AcAPSR1 was dramatically reduced in the roots with a significant induction in the leaf tissue at both the stages. In addition, relative transcript abundance of AcATPS1 , AcAPSK1 and AcSOX1 also increased whereas AcOASTL2, AcNR1 and AcNiR1 decreased under the –N and the –S-N treatments in the leaf tissue, at pre-bulbing. However, at bulbing, transcript levels of AcOASTL2 and AcNR1 also increased under both, the –N and the –S-N treatments. In the roots, at pre-bulbing, the relative transcript abundance of AcHAST1;1LIKE1, AcNRT2;1LIKE1 and all the down-stream reductive S and N assimilation genes investigated declined, while the transcript abundance of AcAPSK1 increased. A similar response was observed at the bulbing stage for most genes except AcSOX1 and AcOASTL3 which increased and AcOASTL1, AcOASTL2 and AcNRT2;1LIKE1 showed no change. Similar to the leaf under the –S-N treatment, the transcriptional profile of the genes investigated in the roots under the –S-N treatment also showed a dominant response to N depletion. In terms of protein accumulation and enzyme activity, AcSiR1 declined in the –S treatment but accumulated in the –N and the –S-N treatment in the leaf tissue at pre-bulbing whereas at bulbing, a decline in protein accumulation was observed under all three treatments. The AcSiR1 enzyme activity declined under the –S and the –N treatment but remained unchanged under the –S-N treatment in the leaf tissue at the pre-bulbing as well as the bulbing stage. In the roots, AcSiR1 accumulated under the –S treatment in both the stages whereas activity remained unchanged. No AcSiR1 protein could be detected under the –N treatment at both stages and in the –S-N treatment at pre-bulbing, whereas the activity increased under these treatments at both stages. Under the –S treatment in the leaf tissue, AcNiR1 accumulated slightly at both pre-bulbing and bulbing whereas the activity remained unchanged. Under the –N and the –S-N treatments, AcNiR1 declined in the leaves at pre-bulbing but accumulated at the bulbing stage. However, the activity remained unchanged at the pre-bulbing stage and was below the assay detection limit at bulbing. In the roots, the AcNiR1 accumulation response was similar to that in the leaf tissue under each treatment at both the stages, whereas the activity declined under all treatments at both stages except at the pre-bulbing stage under the –S treatment where it remained unchanged. The accumulation of a set of targeted metabolites was also compared over the four treatments. A decline in the S containing flavour precursors, including the lachrymatory factor, thiopropanal-S-oxide, was observed in all tissues in response to low S supply. However, glutathione only declined in the leaf at the bulbing stage. An effect of the –S treatment on the accumulation of N-containing metabolites was observed as an accumulation of the amino-acids in the pseudo-stem and the bulb. In contrast, a decline in the accumulation of the amino-acids and derivatives was observed in the leaf at bulbing. In response to the –N treatment, most of the N-containing metabolites declined systemically, including the N-pathway cysteine precursor, O-acetylserine and serine. Flavonol glucosides accumulated in a tissue-specific manner in the pseudostem at the pre-bulbing stage but declined in the bulb tissue. Generally, sugars accumulated systemically at both developmental stages whereas sugar phosphates accumulated only in the leaf and root tissue at the pre-bulbing stage. The lachrymatory factor thiopropanal-S-oxide, accumulated in the leaf at the pre-bulbing stage but declined at the bulbing stage in response to the –N treatment. The metabolite accumulation profile in the plants under the –S-N treatment was similar in all tissues to that of the –N treatment at both the stages. The results from the factorial experiment suggest a hierarchy of N nutrition over S nutrition in A. cepa, where the incorporation and accumulation of S metabolites as well as bulb formation is regulated by N availability. A putatively novel point of interaction between the S-assimilation and the N-assimilation pathways via sulfite reductase (AcSiR1) and nitrite reductase (AcNiR1) was also investigated. Recombinant AcSiR1 and AcNiR1 were each able to reduce both sulfite and nitrite, although with a higher specific activity for the physiological substrate in each case. Further, solid phase binding assay indicated a positive interaction between the two recombinant proteins, although this could not be confirmed by Isothermal titration calorimetry (ITC). In addition to this, in a short term S x N depletion experiment with Arabidopsis, AtSiR1 transcripts only declined in the –S-N treatment in the leaves whereas AtNiR1 transcripts declined in the –S, -N as well as –S-N treatment in wild type plants. In the roots, AtSiR1 transcripts decline in both the –N and the –S-N treatment in the roots whereas no significant change was observed in the AtNiR1 transcripts. In a sir1 T-DNA knock-down line of Arabidopsis, the AtSiR1 and the AtNiR1 transcripts did not change in response to any treatment in both leaf and the roots. Substrate redundancy between AcSiR1 and AcNiR1, in vitro, along with the other interaction studies suggest that although both AcSiR1 and AcNiR1 can reduce both substrates, the possibility of this being a direct point of cross-talk between the two pathways is not conclusively established.

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  • Bacterial attachment to meat surfaces : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand

    Narendran, Valarmathi (2003)

    Doctoral thesis
    Massey University

    The aim of this study was to optimise the hygienic efficiency of slaughter and dressing operations. Three strategic approaches, namely reducing and removing or killing the bacteria attached to meat surfaces, were considered. The second option of removal was selected for development, as current technology inevitably results in bacterial contamination, while killing bacteria on meat surfaces requires drastic treatments that may adversely affect quality parameters. The initial attachment mechanism between bacteria and the carcass surface (reversible attachment) was studied using the collagen film model system. Bacterial attachment to the collagen model was compared with attachment to cut beef muscle and uncut beef muscle using viable count procedure. Scanning electron microscopy and direct microscopic count procedure using an epifluorescence microscope was also developed using both collagen films mounted on microscope slides and collagen coated microscope slides. The collagen film viable count system was the method selected to model bacterial attachment to meat because of ease and consistency of quantification. There was no positive correlation between attachment and many bacterial cell surface factors such as charge, hydrophobicity, protein and polysaccharide surface molecules. Different eluents were used to identify the principal component interfering with single attachment mechanisms on electrostatic interaction and hydrophobic interaction chromatographic columns and on collagen film. Three components interfering with the isolated attachment mechanisms were identified. They were Tween, sodium chloride (NaCl) and mannose. Further column studies indicated that cell surface proteins play a more important role in cell surface negative charge and hydrophobicity than do surface polysaccharides. A wash solution was formulated using the components Tween, NaCl and mannose to reverse what were believed to be the major attachment mechanisms. Further trials with Tween, NaCl and mannose and increasing their concentrations and the application of increased vigorous rinsing also proved ineffective for washing the cells from meat surfaces. This result also supports the hypothesis that bacterial attachment to meat surface is very complex and multifactorial. Elution studies using 10 % Tri sodium orthophosphate pH 12.0 killed the cells rather than removing them and further work will be directed towards the killing.

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  • The self-perceived role of Christian chaplains in New Zealand state schools : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Religious Studies at Massey University

    Yapp, Maria Madelene (2003)

    Doctoral thesis
    Massey University

    State school chaplaincy is a recent phenomenon in New Zealand state schools. It was introduced in the 1980s by the Churches Education Commission (CEC), after the Bible in School programmes, as a voluntary service to care for children in state schools. Currently CEC promotes that a chaplain is a "confidential ear" and "a caring trusted friend" and states that chaplaincy "supports the pastoral care networks in New Zealand schools for students, staff, parents and care-givers and Boards of Trustees". However, definition of the key terms has not been provided and no research has determined what chaplains do. This thesis explores the work of state school chaplains, by participant observation, questionnaires, and interviews, examining who these chaplains are, the nature of Chaplaincy Assessing Resourcing Equipping (C.A.R.E.) courses, and how chaplains "support the pastoral networks of New Zealand schools". Results indicate that they, as a group, display an autonomy, independence, and freedom not clearly discernible in their job descriptions of "confidential listening ears" and "caring trusted friends". They seek the advantages of both remaining apart from and a part of the school establishment. They support state schools, by working under the guidance of the school staff and acting as independent workers and consultants. As "confidential listening ears", they have found their way from school playgrounds to staff meetings. The autonomy chaplains claim may have derived from CEC's failure to provide clear operational definitions of the chaplaincy role, lack of adequate assessing and equipping at chaplaincy courses, and/or lack of sufficient monitoring and supervision on the job. Their extensive involvement in helping and caring for state schools, including evangelization, may have stemmed from the fact that they, as Christian helpers, want to act like Jesus or 'be Jesus'. The meaning of 'being Jesus' is explored by examining the idea of loving one's neighbours as oneself, the example of Jesus, and Jesus' account of the parable of The Good Samaritan. It is suggested that acting like Jesus or "being Jesus' includes not only helping but also evangelization. However, evangelizing in state schools contravenes CEC's recommendations. It is recommended that CEC clarify its intention for state school chaplaincy and consider both the appropriateness and intent of the use of the title 'chaplain', as well as provide precise operational definitions for the key terms of the chaplaincy roles.

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  • Antimicrobial activity of functional food ingredients focusing on manuka honey action against Escherichia coli : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering and Technology at Massey University, Auckland, New Zealand

    Rosendale, Douglas Ian (2009)

    Doctoral thesis
    Massey University

    The goal of this research was to identify functional food ingredients/ingredient combinations able to manage the growth of intestinal microorganisms, and to elucidate the mechanisms of action of the ingredient(s). By developing a high-throughput in vitro microbial growth assay, a variety of preselected ingredients were screened against a panel of bacteria. Manuka honey UMF(TM) 20+ and BroccoSprouts(R) were identified as the most effective at managing microbial growth, alone and in combination. Manuka honey was particularly effective at increasing probiotic growth and decreasing pathogen growth. Testing of these two ingredients progressed to an animal feeding trial. Here, contrary to the in vitro results, it was found that no significant in vivo effects were observed. All honeys are known to be antimicrobial by virtue of bee-derived hydrogen peroxide, honey sugar-derived osmotic effects, and the contribution of low pH and the other bioactive compounds present, hence their historical usage as an antiseptic wound dressing. The in vitro antimicrobial effect of manuka honey has currently been the subject of much investigation, primarily focusing on the Unique Manuka Factor (UMF), recently identified as methylglyoxal, a known antimicrobial agent. This work has taken the novel approach of examining the effects of all of the manuka honey antimicrobial constituents together against Escherichia coli, in order to fully establish the contribution of these factors to the observed in vitro antimicrobial effects. For the first time, it has been demonstrated that the in vitro antimicrobial activity of manuka honey is primarily due to a combination of osmotically active sugars and methylglyoxal, both in a dose-dependent manner, in a complex relationship with pH, aeration and other factors. Interestingly, the manuka honey was revealed to prevent the antimicrobial action of peroxide, and that whilst methylglyoxal prevented E. coli growth at the highest honey doses tested, at low concentrations the osmotically active sugars were the dominant growth-limiting factors. Contrary to the literature, it was discovered that methylglyoxal does not kill E. coli, but merely extended the lag phase of the organism. In conjunction with the lack of antimicrobial activity in vivo, this is a landmark discovery in the field of manuka honey research, as it implies that the value of manuka honey lies more towards wound dressing applications and gastric health than as a dietary supplement for intestinal health.

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  • Hei whenua papatipu : kaitiakitanga and the politics of enhancing the mauri of wetlands : a thesis presented for the degree of Doctor of Philosophy, Maori Studies, Massey University, Palmerston North, New Zealand

    Forster, M. E. (2012)

    Doctoral thesis
    Massey University

    The intent of this doctoral study is to develop a better understanding of the dynamics and complexities of the contemporary practice of kaitiakitanga. There are two specific foci: Māori relationships with whenua, and; Māori-state resource management relations. Together these foci provide a platform to identify implications for the future development and practice of kaitiakitanga. Two interrelated research questions were developed to explore the contemporary practice of kaitiakitanga: what factors shape kaitiakitanga of wetland ecosystems, and; what are the affects of legislating for culture on the practice of kaitiakitanga? A case study of kaitiakitanga of Whakaki Lake, qualitative interviews with active kaitiaki and an evaluation of state environmental policies and laws were used to address these questions and theorise the dynamics and complexities of contemporary kaitiakitanga. This study begins by arguing that customary relationships between hapū and whenua and the ability of hapū to practice kaitiakitanga have been significantly influenced by the introduction of European notions of land tenure and land use. Although the ancestral landscape has changed considerably since annexation of Aotearoa New Zealand, landscapes generally and waterways specifically remain highly valued and continue to contribute significantly to the spiritual well-being and cultural identity of hapū. Transformation of the ancestral landscape, loss of native biodiversity and environmental degradation, however, continue to threaten customary relationships with whenua and the integrity of indigenous ecosystems. As a consequence, protecting the mauri of natural ecosystems has become a key priority for contemporary kaitiakitanga. Protecting the mauri of natural ecosystems is an extension of social responsibilities that emerge from a customary understanding of the environment based on mauri and whakapapa. Therefore it is argued in this study that mauri tū: restoring the balance of fragmented and degraded ancestral landscapes is an imperative that has emerged from a whakapapa-based understanding of the environment and associated relationships with whenua. In situ real life experiences of active kaitiaki involved in this study confirmed the importance of mauri tū as a tribal imperative and provide exemplars of acts of kaitiaki that enhanced or restored wetlands, lakes, waterways and associated natural resources. This study demonstrates that hapū possess a strong sustainability culture or toitūtanga, to ensure that the ancestral landscape continues to nurture the hapū and remains as a cultural and spiritual base for future generations. Tikanga tiaki or guardianship customs that facilitated environmental protection were used by the participants in this study to realise hapū obligations and responsibilities to wetland ecosystems. This demonstrated that contemporary kaitiakitanga is fluid, adaptive and has evolved into highly organised and strategic activities. New derivations of kaitiakitanga such as ecological enhancement and restoration were able to contribute to improved environmental outcomes for fragmented and highly modified wetland and waterway ecosystems. Exercising kaitiakitanga has become synonymous with participation in the state resource management system. Participation however, has only led to a limited range of opportunities for addressing Māori environmental interests. Therefore, this study argues that engagement with the state currently only provides for a limited expression of tino rangatiratanga and kaitiakitanga. The incorporation of the customary concept of kaitiakitanga into statute has resulted in the co-option of kaitiakitanga as state definitions and provisions for Māori relationships with whenua are inadequate for fully realising Māori environmental interests. Furthermore, the state controls the types of activities that can emerge, and by extension regulates Māori participation in resource management which includes the customary practice of kaitiakitanga. Therefore, by participating in the state resource management system, Māori energies are diverted away from hapū environmental priorities, obligations and responsibilities. Critical issues of ownership and addressing environmental degradation are subsumed by the state agenda. The hapū-based restoration experiences explored in this doctorate indicate that it is possible to contest the limitations that exist within current local authority practice and transform the resource management system to provide for a fuller expression of kaitiakitanga. Engagement with the state, constant political pressure and critical reflection of the integrity of the practice of kaitiakitanga are vital if Māori are to transform existing practice. Change is essential if Māori environmental interests are to receive greater attention and to ensure that local authorities are more responsive to hapū understandings of what it means to be an active kaitiaki. Māori-state contests, therefore, are critical to transform state systems, processes and practices towards greater recognition and provisions for core Māori environmental interests and kaitiakitanga.

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  • The impact of traumatic and organizational stressors on New Zealand police recruits : a longitudinal investigation of psychological health and posttraumatic growth outcomes : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University Turitea Campus Aotearoa/New Zealand

    Huddleston, Lynne Mary (2002)

    Doctoral thesis
    Massey University

    Police officers face exposure to traumatic events due to the inherent nature of their profession. As well, as with the employees of any large organization, they are subjected to daily organizational events within their workplace (resource concerns, interactions with co-workers, administrative hassles). Very little is known as to the extent to which these organizational events moderate the development of traumatic stress outcomes. Investigations of police well-being have almost inevitably focused on negative work events and their pathogenic consequences. However, this study seeks to widen this pathogenic orientation by also considering the impact of positive daily work events (uplifts), and by evaluating a possible salutogenic outcome; the development of posttraumatic growth. A longitudinal methodology was utilized to establish baseline measures of traumatic event exposure (the TSS) and psychological well-being (the IES and the HSCL-21). All the 673 recruits who entered police college over one year were invited to participate in the study, and the 512 who completed the first questionnaire were reassessed one year later. The second questionnaire contained measures to assess the impact of the organizational environment (Uplifts and Hassles Scales), police traumatic events (a modified TSS), and posttraumatic growth outcomes (the PTGI). Parametric analyses and hierarchical multiple regression were used to evaluate the study hypotheses and post-hoc analyses investigated moderating effects. The recruits entered the police with high levels of prior traumatic event exposure, which, during the following year substantially increased. Psychological health remained in a robust condition, and psychological distress did not increase, although officers who experienced on-duty and multiple traumatic events had significantly higher traumatic stress than those who did not. Other important findings were that the organizational environment contributed to psychological distress outcomes, and post-hoc analyses indicated that this had an important interrelationship with traumatic stress outcomes as well. Organizational uplifts had a salutogenic effect upon physical health, and aided the development of posttraumatic growth following traumatic exposure. This study has supported the development of a synthesized research orientation that combines salutogenic as well as pathogenic research methodologies.

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  • Infant crying : mothers' perceptions and affective reactions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education at Massey University

    Brennan, Michael Charles (1985)

    Doctoral thesis
    Massey University

    Two studies were conducted in order to examine three major issues arising from recent studies of mothers' reactions to their crying infants. These issues, which arise in connection with the Aversive Stimulus Model of crying, relate to (a) the relationships between cry characteristics and mothers' affective reactions to crying, (b) the variability of cry characteristics of individual infants, and (c) the influence of context on mothers' reactions to their infants' crying. Resting on the premise that the semantic differential is an appropriate technique for addressing these issues. Study A examined the relationships between three sets of semantic differential scales. These were the scales reported by Brennan and Kirkland (1983), which represent three dimensions labelled Affect, Potency, and Evaluation; the scales reported by Zeskind and Lester (1978); and the scales reported by Mehrabian and Russell (1974a), which represent three dimensions of emotion labelled Pleasantness/Unpleasantness, Degree of Arousal, and Dominance/Submissiveness. A combined factor analysis of cry ratings on these scales uncovered the factor structure of the Brennan and Kirkland scales and of the Mehrabian and Russell scales. The factor representing the Brennan and Kirkland Affect scales also represented both the Zeskind and Lester scales and the Mehrabian and Russell Pleasantness/Unpleasantness scales. The Brennan and Kirkland scales were found to effectively discriminate between perceptually different cry sounds. The Mehrabian and Russell scales, however, were found to be lacking in face validity and therefore unsuitable for use with cry sounds. Study B examined the perceptions and affective reactions of mothers listening to their own infants' cries, in two situations - in the home as the crying occurred, and in an experimental situation involving tape-recorded cry samples. The results indicate that: (a) mothers affective reactions to cries did not simply depend upon the aversiveness of the cry sounds, (b) mothers' affective reactions to cries were strongly associated with their attributions regarding the causes and consequences of the cries, (c) cries from the same infant and cries from different infants varied considerably with respect to their perceived characteristics and the types of affective reactions they evoked, and (d) ratings of the tape-recorded cry samples tended to over-emphasise the relationships between cry characteristics and mothers' affective reactions, and to under-represent the extent to which negative affective reactions were experienced by the mothers in the home situation. Several suggestions were made for future studies. These included the adoption of an individualised approach to study: (a) the cry repertoires of individual infants, (b) the types and patterns of affective reactions experienced by individual mothers, (c) mothers' attributions regarding to their own feelings and their infants' behaviors, and (d) the relationships between mothers perceptions, attributions, affective reactions, and actual caregiving behaviors.

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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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  • A comparative study of phosphofructokinase and tagatose 6-phosphate kinase from streptococcus lactis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biochemistry at Massey University

    Fordyce, Alison Mary (1982)

    Doctoral thesis
    Massey University

    In the lactic streptococci glucose is metabolised to lactic acid via the Embden-Meyerhof-Parnas (EMP) pathway. Metabolism of lactose and galactose in these organisms involves participation of the D-tagatose 6-phosphate pathway in which galactose 6-phosphate is metabolised to triose phosphates via tagatose derivatives. Phosphofructokinase (ATP : D-fructose 6-phosphate 1-phosphotransferase, E.C. 2.7.1.11) catalyses the ATP-dependent phosphorylation of fructose 6-phosphate in the EMP pathway. The analogous reaction in the tagatose 6-phosphate pathway, phosphorylation of tagatose 6-phosphate with ATP, is catalysed by a specific enzyme, tagatose 6-phosphate kinase. While phosphofructokinase (PFK) is known to be a major regulatory enzyme in carbohydrate metabolism in most organisms, little is known of the regulatory properties of tagatose 6-phosphate kinase (T6PK). PFK and T6PK were purified from Streptococcus lactis C10 PFK was purified to homogeneity (364-fold purification) by affinity chromatography on Blue-dextran-Sepharose. Unlike PFK, T6PK did not bind to Blue-dextran-Sepharose : a 136-fold purification was achieved using ammonium sulphate fractionation, gel filtration, and ion exchange chromatography. A study of some of the properties of PFK and T6PK from S. lactis C10 showed that these two enzymes are distinct proteins with different physical and kinetic characteristics. S. lactis PFK is a tetramer (MW 145,000 daltons) of identical subunits of molecular weight 33,500 daltons. It therefore appears structurally similar to other bacterial PFKs. T6PK from S. lactis has a molecular weight of approximately 114,000 daltons, a value similar to that of Staphylococcus aureus T6PK which is a dimer. S. lactis PFK exhibited the co-operative binding of F6P and inhibition by high concentrations of ATP relative to F6P which is typical of most bacterial and mammalian PFKs. F6P0.5. and Km (MgATP) values were 0.28 mM and 0.18 mM respectively. ADP stimulated PFK activity, shifting the sigmoidal saturation curve to a more hyperbolic form, with a corresponding decrease in nH. Ammonium and potassium ions also activated PFK, while activity was inhibited by AMP, PEP, FBP, T6P and inorganic phosphate. In contrast to PFK, T6PK showed no co-operative binding of sugar phosphate substrate and was less sensitive than PFK to ATP inhibition. Km values for T6P and MgATP were 0.16 mM and 0.4 mM respectively. Apart from ammonium and potassium ions, no activators of T6PK were found. Activity was inhibited by ADP, PEP, and FBP. PFK and T6PK could catalyse phosphorylation of both F6P and T6P although the enzymes showed a much greater affinity for their natural substrate. Maximum velocities attained were higher with the natural substrate than when the other sugar phosphate was used as substrate. Both enzymes showed similar pH optima and divalent cation requirement. Levels of PFK, T6PK, and Galactokinase (Gal K), enzymes of the Embden-Meyerhof-Parnas, Tagatose 6-phosphate, and Leloir pathways respectively, were measured in strains of S. lactis, S. cremoris, S. diacetylactis and S. faecalis grown on different sugars. Growth on lactose and galactose induced increased levels of T6PK and Gal K activity, galactose generally inducing higher levels of T6PK than lactose. In most strains, addition of glucose to media containing lactose or galactose resulted in lowered activities of Gal K, comparable to those in glucose-grown cells. In contrast, T6PK activity was generally not suppressed by growth on glucose plus lactose, while in growth on glucose plus galactose, T6PK activity was approximately 50% of the activity in cells grown on glucose alone. PFK activity was generally unaffected by the sugar in the growth medium. In spite of changes in specific activities of PFK and T6PK throughout the growth period of S. lactis, the ratio of PFK : T6PK remained fairly constant. The properties of S. lactis PFK and T6PK are compared to those of these enzymes in other bacteria, and the possible role of T6PK in regulation of carbohydrate metabolism in S. lactis is discussed.

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  • The life history strategy of Carex pumila Thunb. (Cyperaceae), a rhizomatous perennial pioneer species on the sand plains of the dune system of coastal Manawatu : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Botany

    Burgess, Robert Edward (1984)

    Doctoral thesis
    Massey University

    The life history strategy of Carex pumila Thunb. (Cyperaceae), a major colonist of raw moist sand on the sand plains of coastal Manawatu, New Zealand, is outlined. By virtue of the continuous formation of sand plains, sites suitable for colonization are a permanent feature of this habitat and vegetation of increasing seral maturity is represented at any one time across a series of adjoining deflation hollows and low dunes. It is proposed that the species is an r-strategist well suited to exposure, nutrient stress and seasonal flooding. Amelioration of these conditions by deliberate perturbation treatments resulted in this seral species responding in a way that ultimately lead to its more rapid demise. The species has a rhizomatous perennial growth habit. Tne modular construction of its rhizome system is described for the first time. Similarly, the occurrence of both long and short sympodial rhizome branches and of large-diameter sinker roots have not been previously described in the literature on this species. Its floral development appears to be environmentally cued. Emergence of inflorescences occurrs in early October. Maximum size of dissemules is obtained by early January. Subsequently seeds are shed and the shoots bearing them die. The species is essentially allogamous, although in a laboratory experiment, it was found to be partially self-compatible. Self-pollination must be expected in the field since neighbouring shoots are likely to be part of the same genet. Field studies are reported in which the performance of Carex pumila was monitored, firstly at sites of increasing seral maturity both in space and in time, and secondly in response to perturbation treatments. Populations showed a pattern of development that included a juvenile phase of rhizome expansion, an adolescent phase of increasing shoot density, a mature phase in which a proportion of the shoots were reproductive, and a senile phase of diminished growth and seed production. Phasic development was more protracted on the more stressed and more exposed sites. Other species more rapidly filled the space made available by the death and decay of Carex pumila shoots, than the colonist itself. As a pioneer, the species is doomed to extinction on the sites it colonizes. In a perturbation experiment, the sward mass of the total vegetation per unit area was increased at all sites by nitrogen fertilizer, applied as ammonium ions at a rate of 50 kg N / ha. Where the Carex pumila population was in a senile phase in an old deflation hollow, the increase was made mainly by other species. In younger populations on a low dune, the density of shoots and expanding buds of Carex pumila were markedly increased by the fertilizer treatment. Associated with this, a significant increase occurred in the proportion of the total dry weight of vegetative branches in rhizomes and in green leaves. A nitrogen limitation to seed yeild was indicated at the older low dune site. Here nitrogen fertilizer addition increased seed output per unit area by increasing both seed number per culm and seed size. By contrast on the younger low dune site, seed output per unit area was unchanged by the perturbation. In this population, reallocation of resources within fertile shoots, which was seen as an increased number of seeds per culm, was offset however by a reduction in fertile shoot density. Seed reproductive effort varied between 0 and 16% of total biomass, whereas rhizome allocation was more variable; up to 100% of biomass where the species was invading an embryonic deflation hollow. As a proportion of the biomass of fertile shoots alone, seed reproductive effort estimates of up to 32% were obtained. The post-anthesis photosynthetic contribution of female spikes to final seed weight was estimated at 26%, in a growth room experiment. This estimate is considered conservative given that final seed weight was not significantly reduced by defoliation and shading of the culm. Thus, the allocation of biomass to seeds cannot be considered a drain on the carbon resources of the plant that might otherwise be allocated to growth or some other plant function. Total nitrogen concentrations were dissimilar in different plant parts and, for comparable organs, between populations of different ages. Thus, allocation patterns to component parts based on dry weight and total nitrogen were different. Given that nitrogen was seen to be limiting growth in this seral habitat, the allocation of this resource is likely to be of greater significance in the evolution of life history strategies than is that of dry weight.

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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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  • Moral uncertainty and contemporary children's fantasy fiction : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in English at Massey University, Albany Campus, New Zealand

    Lochead, Anne (2013)

    Doctoral thesis
    Massey University

    This thesis studies the interplay between mythos (story) and ethos (ethical character) in contemporary children’s fantasy fiction. In recent decades, this relationship has been complicated by two contradictory, but related, ethical tendencies. Postmodernism characteristically resists unitary accounts of morality, celebrating pluralism. Within the last twenty years, however, there has been a groundswell of interest in rethinking ethics and retrieving values from endemic moral uncertainty, often referred to as an ethical turn. This thesis contends that children’s fantasy fiction has evolved into a literature that creatively engages with this contradiction, simultaneously refusing moral certainties and demanding unflinching ethical values. This evolution is explored by comparing a selection of children’s fantasy fiction published from 1995 to 2012 with earlier exponents of this genre as well as other literary texts. The analysis is conducted through a framework of expanding ethical horizons, starting with a focus on personal contexts and then progressing to the social, political, and ideological. The thesis employs an inter-textual method. Ethical concepts are teased out by bringing literary texts into dialogue with each other and exploring links between them. Ideas from critical theory are then used to extend the trajectory of the ethical themes suggested by the fictions. Through this method, themes and texts are woven into an ethical narrative about children’s fantasy. This thesis approaches storytelling as a portal into the imagination where writers, readers and protagonists actively forge moral meaning. Traditionally, stories rich in symbol not only entertained their audiences, but also encapsulated their societies’ moral values. When society is presented metaphorically, familiar assumptions are estranged, enabling readers to see the world anew and imaginatively reconstruct their worldviews. In recent children’s fantasies, both child protagonists and child readers are required to be moral thinkers. This demonstrates a shift, not only in how ethical dilemmas are contended with today, but, by addressing children as ethical subjects, in how much moral agency is attributed to children. Children’s fantasy is a rich and layered genre particularly suited to engaging with contemporary ethical dilemmas and uncertainties. This thesis affirms its role in exploring ethical meaning and action and transmitting positive values in a climate of moral uncertainty. Emerging from this fiction, and incongruous to both postmodern consumerist society and postmodern suspicion of categorical moral imperatives, is an ethics of self-transcendent love.

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  • Development of methodologies for the characterisation of biochars produced from human and animal wastes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science, Institute of Agriculture and Environment, College of Sciences, Massey University, Palmerston North, New Zealand

    Wang, Tao (2013)

    Doctoral thesis
    Massey University

    Biochar is charcoal made from waste biomass and intended to be added to soil to improve soil function and reduce emissions from the biomass caused by natural degradation to CO2. Biochar technology has many environmental benefits, such as carbon (C) sequestration, waste management, soil improvement and energy production. High quality biosolids (e.g., low in heavy metals) and animal wastes represent an adequate feedstock for production of biochars. Wide variation in biochar properties, dependent on feedstocks, process conditions and post-treatments, lead to large uncertainties in predicting the effects of biochar application on the surrounding ecology, and the productivity of particular crops under specific pedoclimatic conditions. It is essential to well-characterise biochars prior to its incorporation into soils. Therefore, the aims of this thesis were (i) to investigate the C stability and nitrogen (N) and phosphorus (P) availability in biochars produced from municipal and animal organic wastes at different pyrolysis temperatures; and (ii) to develop simple and robust methods for characterisation of C stability and nutrient availability in biochars. Two types of feedstock, (i) a mixture (1:1 dry wt. basis ratio) of alum-treated biosolids (from anaerobic digestion of sewage, ~5% dry wt. of Al) and eucalyptus wood chips (BSe), and (ii) a mixture (1:1 dry wt. basis ratio) of cattle manure (from a dairy farm) and eucalyptus wood chips (MAe), were used to produce biochars at four different pyrolysis temperatures (highest heating temperature: 250, 350, 450, and 550°C). The stability of C in charred materials increased as pyrolysis temperature increased, as proved by the increase of aromaticity and the decrease of atomic H to organic C (H/Corg) ratio, volatiles to (volatiles + fixed C) ratio, C mineralisation rate and % K2Cr2O7 oxidisable C. According to the IBI Guidelines (IBI 2012), an upper H/Corg ratio limit of 0.7 is used to distinguish biochar samples from other carbonaceous biomass based on the consideration of C stability. According to this classification system, MAe-450 and MAe-550 biochars complied with this specific C stability requirement; this was also the case of BSe-450 and BSe-550 when their H values were corrected to eliminate the contribution of inorganic H from Al oxy-hydroxides. Both organic H (Horg) and Corg forms were used in the calculation of this index instead of their total amounts, as the latter would also include their inorganic C or H forms – which can represent a considerable amount of C or H in ash-rich biochars – and these do not form part of the aromatic structure. Therefore, various methods, including titration, thermogravimetric analysis (TGA), acid fumigation and acid treatment with separation by filtration, were compared to quantify the carbonate-C in biochars. Overall, the titration approach gave the most reliable results as tested by using a CaCO3 standard (average recovery>96% with a relative experimental error MAe biochars> BSe biochars > Sechura phosphate rocks (SPR). Plant availability of P in biochars could be predicted from the amount of P extracted in 2% formic acid extractable P (FA-P). In addition, resin-P was considered as a useful test for characterising P bioavailability in soils fertilised with P-rich biochars. However, more investigations with a wider range of soils and biochars are needed to confirm this. Pyrolysis temperature played a minor role on P availability in biochars produced below 450°C compared to the influence of the type of feedstock. This was supported by the results on (i) plant P uptake, (ii) 2% formic acid extraction, and (iii) successive resin P extractions. The availability of P in biochars produced at 550°C decreased noticeably compared with that in lower temperature biochars. The Hedley P fractionation procedure was also carried out to examine the forms and transformation of P in biochar after its application into soils under the influence of plant growth. Generally, biochar P contributed to the readily available resin-P and moderately available NaOH-Pi fractions, and some equilibrium likely existed between these two fractions, both of which provided P for plant uptake. In a plant-sandy soil system, depletion of P in resin-P and NaOH-Pi fractions was attributed to plant uptake rather than conversion into less available P forms (e.g. from NaOH-Pi to H2SO4-P). High-ash biochars with high P concentrations could be potential slow-release P sources with high-agronomic values. To determine appropriate agronomically effective rates of application and avoid the risk of eutrophication associated with biochar application, it is recommended to determine available P using 2% formic acid extraction in biochars, so that dose, frequency and timing of application are correctly established. All the information obtained in this thesis will support the future use of the biochar technology to recycle nutrients and stabilise carbon from agricultural and municipal organic wastes of good quality.

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  • The design of nutritional food products for a developing country : a thesis presented in partial fulfilment of the requirements for the degree of Ph.D. in Product Development

    Edwardson, William (1974)

    Doctoral thesis
    Massey University

    A systematic methodology was developed for designing food products for the Philippines. This was the initial stage of an investigation at Massey University into the application of quantitative product development techniques to the food industry in developing countries. A study of economic, nutritional and food industry conditions indicated that Taiwan, Korea and the Philippines best satisfied the conditions necessary for the use of product development in the food industry. The Philippines was chosen for this first investigation and the quantitative study was on the selection of raw materials in formulation according to their nutritional properties. The selection of raw materials in the product development was made quantitative by use of linear programming. A linear programming model was developed to select, from a list of one hundred and seventy raw materials indigenous to the Philippines, a raw material mixture capable of satisfying twenty-six nutrient requirements as well as several interrelationships between nutrients, at a minimum cost. In the development of this model, investigations were made on the effects of altering nutritional requirements, raw material costs and compositional data and also the variety of raw materials. The linear programming model was found particularly useful for investigating the effects of changes in the nutritional requirements and in raw material costs, but rather unpredictable for changes in raw materials. The precision of the model was much greater than could be expected of the nutritional composition data. The mixture of raw materials selected to meet the Philippine nutritional requirements was developed, using the product development system, to an acceptable canned meat-loaf-type product. This product was selected, from a number of systematically generated product ideas, by a critical evaluation method, based on information on processed food eating patterns, food processing facilities and processed food distribution systems, obtained during a visit to the Philippines in 1973. This product was designed to be manufactured in large meat processing plants in the Philippines and distributed to the small stores throughout the country. The linear programming model was also used to guide the design of a food product enriched with chemical nutrients and capable of rapid introduction to Philippine diets to supplement the basic rice meal. The linear programming technique provided quantitative data for evaluation of the feasibility of enrichment with various types of food materials and chemical nutrients for the cost of various levels of enrichment and for design of product formulations, allowing for nutrient losses during processing. A coconut bun with nutrient enriched filling was developed. This product could be manufactured in the many bakeries scattered throughout the Philippines. Chemical analysis of the two products showed reasonable agreement with calculated nutrient levels, but generally nutrient levels were below calculated levels, implying that some scaling up of nutrient requirements may be necessary for this model. The real value of the systematic methodology cannot be finally assessed until an attempt is made to implement the industrial production in the Philippines and introduce the products into the diets. This first stage, of the development of the raw material selection model has provided a basis for further work on inclusion of the other properties of the raw materials such as eating quality, so that a comprehensive model for the quantitative design of foods can be finally achieved.

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  • An evaluation of microcomputer assisted instruction for teaching word recognition to mentally retarded adults : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education, Faculty of Education, Palmerston North, New Zealand

    Ryba, Kenneth Allan (1980)

    Doctoral thesis
    Massey University

    This study compared the utility of computer assisted instruction with more conventional interpersonal tuition for teaching word recognition skills to mentally retarded adults. A second aspect of the research was to evaluate acquisition, retention, and transfer of learning using two common methods of instruction; these were errorless discrimination (word-focus only) and paired associate learning (picture-word focus). Recognition of words was selected as the experimental task on the basis that this was a practical academic area that traditionally involves large amounts of teaching time, primarily within the realm of drill and practice procedures. The sample comprised 52 subjects who were drawn from three special education facilities in Palmerston North, New Zealand (a Special School, and two Vocational Training Centres). Subjects were screened initially on tests of visual perception and letter discrimination to ensure that they possessed requisite skills to benefit from participation in training. Pre-testing was carried out to determine whether subjects were able to recall or recognize any of the words to be taught. All subjects entering the experiment knew two or less of 16 words selected for inclusion in the training programmes. Subjects were randomly assigned to computer assisted instruction or individual tuition groups with 26 persons placed in each group. Within each group, subjects were again randomly allocated to receive errorless discrimination or paired associate modes of instruction. This 2 X 2 classification resulted in 13 subjects being placed in each subgroup. Two modules each containing eight words were used for training. Both the individual instruction and computer groups were given a total of 10 training sessions, or five sessions for each of the two modules. A modified microcomputer was interfaced with a sound-on-slide projector to provide both audio and visual instruction. Parallel teaching programmes were developed for administration by computer or individual tuition. The first programme (errorless discrimination) required subjects to select target words from a series of increasingly complex word discriminations with no picture cues provided. A second teaching method (paired associate learning) involved the pairing of pictures and words. Subjects were instructed to select target words from a list of printed items that matched referent photographs. Thirteen senior special education students (Teachers College Graduates) carried out the individual training while the experimenter supervised the computer based programmes. Progress in training was assessed by comparing pre- and post-test performance on Word Recognition (verbal labelling), Word Identification (pointing on cue), and Picture-Word Matching. Transfer of learning was evaluated using situational tests requiring that subjects match printed words with real life objects. Tests of retention were conducted four weeks after completion of training. A repeated measures design was used with counterbalancing to control for possible confounding effects of list order (Modules). The findings revealed that both computer assisted instruction and interpersonal tuition resulted in very similar learning outcomes with regard to acquisition, retention, and transfer of learning. No reliable differences were found between the two groups or modes of instruction in terms of training method. It was advanced that some common features of programmed instruction (e.g. active participation, self-pacing, over-learning, and immediate feedback) may have accounted for these equal gains in performance. In respect to the question of the potential utility of microprocessor technology in special education, this research points to the efficacy of computer assisted instruction for drill and tutorial practice. Specifically, the computer provides a highly structured learning experience that has the potential to assist retarded learners in organising input materials. Evidence from this study suggests that computer related learning environments give the adult learner considerably more control of the teaching situation, and provide consistent reinforcement that is not so readily administered through conventional forms of instruction. Finally, it was proposed that the relatively impersonal, though highly interactive, nature of the computer may avoid the triggering of perceptions of failure that can impede performance of handicapped learners. This dissertation is dedicated to my wife, Beth, whose understanding and support provided me with the encouragement to complete this work.

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