96,610 results

  • Digital reporting formats and users of financial reports : decision quality, perceptions and cognitive information processing in the context of recognition versus disclosure : a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Accountancy, Massey University

    Ghani, Erlane K.

    Thesis
    Massey University

    The evolvement of digital reporting has changed the way financial information is prepared and disseminated (Debreceny and Gray, 200 1 ). Previous research has shown that digital reporting has increased, particularly in the last five years, and this usage is characterised by greater volumes of business and financial information over that traditionally provided in print-based mode (Smith, 2003). The new opportunities and benefits offered by digital reporting are matched by challenges and implications not only for the preparers and auditors but also for users. It is expected that in the near future, financial reporting will move entirely from the primarily print-based mode to digital-based mode as the primary information dissemination channel (Oyelere et aI., 2003; Fisher et aI., 2004). Research in the area of digital reporting has been conducted in the past decade. Within this research, a considerable number of issues have been raised. These issues relate to various parties, such as policy makers, preparers, auditors, system designers and users. While several research questions and hypotheses concerning these parties have been posed and investigated, most of the research questions and hypotheses have been formed from a preparers' perspective, leaving the examination of issues from a users' perspective largely unexplored. This study focuses on users. It examines the effect of presentation formats on decision makers' performance in relation to decision quality, perceptions and cognitive information processing in the digital reporting environment. It aims to extend the digital reporting literature. This study extends the existing body of knowledge on digital reporting environment in several ways. First, this study examines the effect of presentation formats on the quality of users' decision making. This study follows Kleinmuntz and Schkade (1993) who described 'decision quality' in the context of two cost-benefit dimensions in relation to decision makers' cognitive processes, namely decision accuracy and cognitive effort. Decision accuracy reflects the ability of a strategy to produce an accurate outcome while cognitive effort reflects the total cognitive expenditure incurred in completing a task. Second, this study examines users' perceptions of three digital presentation formats: PDF, HTML and XBRL. This study compares subjects' perceptions of usefulness and ease of use of the three presentation formats with their actual outcome. It also includes examining whether perceptions are an important factor in influencing preferred presentation format. Finally, this study examines whether digital presentation formats address the concern over functional fixation in the accounting context of 'recognition versus disclosure' in the reporting of financial information. This study used public accounting practitioners in New Zealand as participants. Sixty two subjects participated in the experiment, which involves an experiment exercise and a post experiment questionnaire. The results indicate that presentation formats impact on decision accuracy. This finding is consistent with previous studies conducted using non-digital presentation formats such as tabular and graphical in the psychology and information systems literature (Stock and Watson, 1984; Dickson et aI., 1986; Iselin, 1988; DeSanctis and Jarvenpaa, 1989; Mackay and Villareal, 1987; Hard and Vanacek, 1991; Stone and Schkade, 1991; Anderson and Kaplan, 1992; Bricker and Nehmer, 1995; Ramarapu et aI., 1997; Frownfelter-Lohrke, 1998; Almer et aI., 2003). The results, however, indicate that presentation formats do not impact decision makers' cognitive effort. These findings suggest that preparers, standardsetters and regulatory bodies should recognise that presentation format impacts on users' decision making processes and select appropriate formats that lead to improvement in decision making. Additionally, the results indicate that users' perceptions of the usefulness and ease of use of the reporting technologies are similar across the three presentation formats. The results also show that users' perceptions do not necessary correspond to actual performance. Users' perceptions are found to influence their preferred presentation format. The findings of this study provide useful insights on users' perceptions, performances and preferences of the digital presentation formats. Such results provide a holistic and comprehensive view of the importance of perceptions and the effect of presentation formats on decision makers' performance. This is particularly relevant since if more advanced forms of digital reporting are to be encouraged, then there is also the need for users to be made more aware of the benefits to be gained from the different forms of presentation. Finally, the results show that of the four recognised stages of information processing (i.e. acquisition, evaluation, weighting and judging information), functional fixation is found to only exist at the judgment stage. However, the effect of presentation format is only significant at information evaluation stage. The results indicate that the interaction between presentation formats and placement of information does not affect decision makers' information processing. This suggests that presentation formats do not solve the concern about recognition versus disclosure (functional fixation) in information processing stages. These fmdings are not consistent with Hodge et al. (2004) but are consistent with Luft and Shields (2001) who suggest functional fixation could not be alleviated because the accounting itself would affect the allocation of people's attention. This study extends the literature on presentation format by examining the quality of decision making arising from the use of different presentation formats in a digital reporting environment. It provides evidence that users' perceptions of ease of use of a presentation format do not necessarily correspond to their actual performance (cognitive effort) once a particular task has been performed. This study also provides evidence that the acceptance of a technology is highly dependent on the perceptions of that technology. Therefore, limited knowledge and appreciation of the capabilities of a technology may have the undesired effect of deterring use of the technology although it may improve performance.

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  • Late quaternary lahars from Mount Ruapehu in the Whangaehu River, North Island, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosoophy in Soil Science at Massey University

    Hodgson, Katherine Anne

    Thesis
    Massey University

    The stratigraphic record of lahars in the Whangaehu River reveals that in the past 180,000 years this route has been one of the main conduits for lahars from Mount Ruapehu, the highest active andesitic stratovolcano in the Central North Island of New Zealand. Both debris flows and hyperconcentrated flows have engulfed surfaces up to 160 km distance from the Volcano. Eight episodes of laharic activity are recognized by the distinctive lithology and similar age of their deposits. The newly defined upper Pleistocene Whangaehu Formation provides evidence for the earliest lahar event in the Valley, c. 180,000- 140,000 years ago. There is only meagre evidence for laharic activity following this event until the Ohakean and Holocene, although two new informally named deposits - the Mangatipona pumice sand (c. 37,000 years B.P.) and Apitian lahars (c. 32,000-25,500 years B.P) - are recognized, of minor extent. The formerly defined late Quaternary Te Heuheu (c. 25,500- 14,700 years B.P.), Tangatu (c. 14,700-5,370 years B.P.), Manutahi (c. 5 ,370-3,4600 years B.P.), Mangaio (c. 4,600 years B.P.) and Onetapu (< c. 1,850 years B.P.) Formations are here described and interpreted. Triggering mechanisms for lahar deposits are distinguished based on lithological criteria. (a) Bouldery deposits in the Whangaehu Formation are interpreted to have been emplaced by a single highly competent debris flow triggered by a southerly-directed flank collapse at Mount Ruapehu. This debris flow was competent enough to transport boulders up to 2 m in diameter over 140 km from the Volcano. Bouldery deposits are also recognized in the Onetapu Formation, but are restricted to higher gradient surfaces on the Mount Ruapehu ring plain. The Onetapu Formation deposits are interpreted to have been emplaced by lahars resulting from catastrophic drainage of Crater Lake, which occupies the active crater on Mount Ruapehu. (b) Pebbly and sandy deposits are interpreted to have been emplaced by low competence debris flows and hyperconcentrated flows. These lahar deposits are recognized in all formations described. The lithology in these deposits is commonly pumice and they are interpreted to have been triggered by eruptions and/or high rainfall events at the Volcano. Formations, and individual members within Formations, were dated by radiocarbon dating of organic material found below, within or above lahar deposits, or by coverbed stratigraphy. Both rhyolitic and andesitic tephras provided recognizable time planes in the late Quaternary coverbeds overlying lahar deposits. In this study quantitative analysis of quartz abundance, which is shown to vary between loesses and palaeosols, is used as an indirect means of establishing a surrogate for past climate changes which have been correlated to the deep sea oxygen isotope curve. A minimum age for the newly defined Whangaehu Formation is established by this method. The accumulation rate for lahars in the Whangaehu River has accelerated from 1 km3 every c. 23,000 years in the past c. 160,000 years to 1 km3 in 589 years in the past c. 2,000 years. This acceleration probably results from the increased frequency of lahars in the River following the development of Crater Lake c. 2,000 years B.P. According to this pattern an estimated 0.17 km3 volume of lahars could be anticipated over the next 100 years. If the 2,000 year accumulation rate were to be met over the next 100 years there would be 170 lahars of l0[superscript]6 m3 in this time interval , or 17 lahars of 10[superscript]7 m3 (or 1.7 lahars of 10[superscript]8 m3). The largest reported volume for an historic lahar is 10[superscript]6 m3 and these have occurred on average once every 30 years. The accumulation rate for historic lahars is 0.0054 km3 in 100 years. Therefore, although the accumulation rate appears to have slowed down, further large lahars with magnitudes 10 or 100 times greater than those witnessed could be expected.

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  • Managing the shopping centre as a consumption site : creating appealing environments for visitors : some Australian and New Zealand examples : a thesis in presented [sic] in partial fulfilment for the requirements for the degree of Doctor of Philosophy in Geography at Massey University

    Bowler, Susan Mary

    Thesis
    Massey University

    The position occupied by retailing within the production - consumption debate is the subject of dispute. As neither sphere can be fully analysed in isolation such argument may be somewhat irrelevant. The need to conceptualise the two spheres together, therefore, has informed this research on the created environments of shopping centres. Planned and managed shopping centres are a ubiquitous part of the built environment in 'advanced capitalist' nations. There has been a tendency, however, for researchers to focus upon exceptional centres rather than everyday examples of this particular consumption site. They have concentrated upon how shopping centre environments appear to be created and the appeal researchers assume they may have for an observer. My research for this thesis, however, has been concerned with how managers create shopping centre environments and how they are designed so as to appeal to their centres' perceived markets. This was done by conducting semi - structured interviews with a number of centre managers in Australia and New Zealand . The unified ownership and management structure of shopping centres makes it easier for their created environ ments to be controlled. Shopping centre researchers and those who have attempted to read the built environment as if it were a text have tended to assume that the architectural styles used will reflect dominant ideologies and that they are powerless to interpret or alter them in any other than the manner intended by the designers, developers and owners. Many of the managers recognised, however, that shoppers cannot be forced to visit nor can they be made to purchase. Research was therefore commissioned by management as a way of gaining socio - economic information on the individuals in their catchments , their 'needs' and desires. Selecting tenants which would appeal to their markets and arranging them in a manner which reflected the way people liked to shop was thought to be paramount to the success or otherwise of a centre. Some managers, for example, claimed that there was a difference between 'doing' the shopping (which is a chore) and 'going' shopping (which is enjoyable ) and that this needed to be kept in mind when they positioned retailers within their centres. Consumption does not only involve the purchase of commodities for their use and/or sign value but is also concerned with experience. Managers attempted to provide their shoppers with an enjoyable experience when they visited their centres by, for example, the creation of an appealing ambience and by either suggesting or insisting, respectively, that the common areas and leased spaces be regularly refurbished.

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  • Surface characteristics of an adhesive thermophilic spore-forming Bacillus, isolated from milk powder : 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

    Palmer, Jon Stuart

    Thesis
    Massey University

    The growth of thermophiles during the manufacture of milk powder leads to a progressive increase in the number of thermophilic bacteria contaminating the final product. The limited residence time of the milk in the plant during milk powder manufacture and the concentration effect of converting milk into milk powder cannot explain the number of thermophiles found in the final product. This suggests that thermophiles are attaching to the large surface area of stainless steel found within a milk powder plant and then growing and developing into biofilms, with individual cells and/or biofilm fragments sloughing off into the product line and thus contaminating the final product. The aim of the present study was to investigate the attachment mechanisms that enable the thermophile Anoxybacillus flavithermus (B 1 2) to attach to stainless steel surfaces. Passing a B 1 2 culture through a column of stainless steel chips, collecting the first cells to pass through, re-culturing and repeating the process six times, resulted in the isolation of a mutant, labelled X7, with lO-fold reduced ability to attach to stainless steel as well as a reduced ability to attach to plastic and glass. A comparison of bacterial cell surface properties indicated that X7 was less hydrophobic than its parental strain B 1 2 . Cell surface charge measurements also suggest that X7 has less net negative surface charge. Disruption of extracellular polysaccharides and DNA appeared to have no effect on the attachment process. Removal of surface proteins caused a reduction in attachment of B 1 2 and X7 as well as a reduction in surface hydrophobicity suggesting surface protein involvement in both. Analysis by two-dimensional gel electrophoresis of lysozyme/mutanolysin extracted surface proteins revealed two proteins expressed at reduced levels in X 7 compared with B 1 2 . One protein was identified by mass spectrometry as the cytoplasmic enzyme Formate acetyltransferase. The role of Formate acetyltransferase and the second unidentified protein on the attachment process of Anoxybacillus flavithermus remains unclear.

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  • Concentration of dairy flavours using pervaporation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Auckland, New Zealand

    Overington, Amy Rachael

    Thesis
    Massey University

    The food industry could potentially benefit from using pervaporation, a membrane process, to concentrate flavours. This research aimed to investigate its application for concentrating flavours in dairy process streams. Pervaporation experiments were carried out at a range of operating conditions, using hydrophobic membranes. The feed mixtures were either aqueous model solutions of dairy flavour compounds (acids, esters and ketones), complex model mixtures containing flavour compounds plus non-volatile dairy components, or real dairy products. Flavour compound enrichment factors ranged from below one to above 30, with esters and ketones being concentrated more effectively than acids. Thus, the flavours could be partially fractionated based on their chemical structure. The permeation of acids was reduced by approximately 50% when the feed pH was increased to near their p Ka values. For flavour compounds with lower molecular weights than approximately 1 20 g mol- I , permeation was controlled mainly by sorption i n the membrane; for larger compounds it was controlled mainly by diffusion through the membrane. The mass transfer of each flavour compound increased with temperature, following an Arrhenius-like relationship. The activation energy was a function of each compound's heat of sorption, its molecular weight, and the elastic modulus of the membrane. The activation energy was also related to the Arrhenius preexponential factor. Thus, fluxes could be estimated through empirical correlations. The non-volatile feed composition was an important factor influencing the pervaporation performance. Milk protein isolate (4% w/v) or lactose (6% or 1 2% w/v) bound with the flavour compounds in the feed, thus lowering the enrichment of sorption-controlled compounds. Milk fat (up to 38% w/v, in the form of cream ) reduced the enrichment of all the flavour compounds tested. Esters and ketones became unavailable for pervaporation as they partitioned into the fat phase; acids remained mainly in the aqueous phase, but their permeation was reduced because the added cream increased the feed pH. Experiments with real dairy products showed that pervaporation could be used to concentrate diacetylin starter distillate, and to selectively recover short-chain esters from ester cream. Of these two products, starter distillate is the more promising for use as a pervaporation feed stream.

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  • Isolation, characterization and possible biocontrol application of Bdellovibrionaceae (BD) isolated from NZ sources : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) at Massey University

    Ahmed, Muftikhar

    Thesis
    Massey University

    Bdellovibrionaceae (BD) are unique, predatory, endoparasitic, Gram-negative bacteria. As the world's smallest living hunter they prey on other Gram-negative bacteria giving them potential as biological control agents. Prior to this study, however, there were no reports of BD in New Zealand. The overall aim of this research was to isolate BD from New Zealand sources, characterise them and investigate their potential role as a biological control agent. The history, characteristics, life cycle and mechanism of predation of this organism are reviewed and the possibility of the industrial applications of BD, are discussed. In this study, a halophilic species of BD was isolated from fourteen coastal sea water sites around New Zealand. Thirteen isolates were characterised using proven characterisation techniques including general, microscopic and molecular techniques. It was found that the isolates were taxonomically identical or very closely related to each other and belong to the genus Bacteriovorax. The predation pattern of BD isolates was examined against a group of Gram negative bacteria in solid and liquid media. The predation patterns and efficiencies of the different BD isolates were similar, which confirms that the BD isolates are closely related, are selective in their predation, and prey on some Gram-negative bacteria but not all. The rapid loss of culture viability of BD is well known, but no studies have been reported to date on the survival of pure cultures of BD at different temperatures. The survival rate of BD in dense suspensions at different temperatures without host bacteria was investigated and it was observed that pure BD cultures can be stored with minimal reduction in numbers at temperatures ranging from 4°C to 20°C. However, significant reductions in numbers were observed at -1 8"C, 30°C and 37°C after 13 to 16 days. The effects of the 13 New Zealand BD isolates on the growth of a population of Photobacterium phosphoreum were examined to select the best isolate for in vitro application. All of the isolates tested had considerable reduction effect against P. phosphoreum. Some isolates were more effective than others, despite their taxonomic similarity to each other. The isolate OT2 was selected for further studies based on these results. The in vitro efficacy of BD was assessed against late exponential cultures of a seafood spoilage bacterium, P. phosphoreum, originally isolated from Cod fillets from Denmark. Loglo reductions of P. phosphoreum and some other Gram-negative bacteria ranged from 4.5 to 4.8 after 9 h of incubation at 25OC. BD was effective in reducing the numbers of P. phosphoreum at pH 5.5 to 8.5 and salinity 0.9 to 4.5% (wlv). A significant interaction was observed between the prey and predator concentrations and nutrient concentration. Prey concentrations were observed to be the most vital factor in predation and the most favourable predation conditions were at a prey concentration of -8 loglo colony forming units (CFU)/mL, together with a predator concentration of 3 - 7 loglo plaque forming units (PFU)/mL and a prey : predator ratio of >5.0. The thresholds of the prey and predator concentrations for predation were observed to be 3.7 loglo CFUImL and 3.9 loglo PFUImL, respectively. The trials carried out in this study focused on the efficiency of BD on a pure culture of one organism, P. phosphoreum and not on mixed cultures of Gramnegative spoilage bacteria, the normal condition observed in saltwater fish. There has been very little research in this field and the results of these trials suggest further investigation into the effect of BD on mixed cultures of Gram-negative spoilage organisms is warranted. Since only one isolate of BD (OT2) was examined against only one spoilage bacterium (P. phosphoreum) in liquid medium, the evidence of these findings must be restricted to these particular conditions. Future studies, using a range of BD isolates against a mixture of spoilage and pathogenic organisms in solid medium are warranted. The biopreservation capability of BD in extending the shelf life of king salmon was evaluated. A significant effect was observed at 20°C but not at 10°C. At 20°C the shelf life was extended through extension of the lag phase of growth of the prey bacteria and a reduction in total numbers attained. Sensory evaluation of the salmon product being tested confirmed that the shelf life was extended. However, at 10°C there was no reduction in prey organisms, which suggested that the strain of BD used is ineffective at refrigeration temperatures.

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  • Systematics of the Australian longicorn beetle genus Uracanthus Hope 1833 (Coleoptera: Cerambycidae: Cerambycinae: Uracanthini) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science (Entomology) at Institute of Natural Resources, Massey University, Palmerston North, New Zealand

    Thongphak, Duangrat

    Thesis
    Massey University

    Uracanthus is a large group of longicorn beetles in the Australian Region. The larvae of this genus are borers of at least 31 genera of trees and parasitic plants, including some economically important crops such as citrus, litchi, peach, plum, and apricot. Several species are important pests of orchards. Adults visit flowers of various tree species and are attracted to the light. In this thesis, I undertook a thorough taxonomic revision, analysed the phylogeny using morphological and molecular characters, and appraised biogeographic distribution of the genus. In the taxonomic revision, I redefine the scope of the genus, describe and illustrate new and previously known species, and provide a key to all species. The revised Australian Uracanthus includes 39 species, eight of which are established as new to science: U. pseudogigas sp. nov., U. maculatus sp. nov., U. griseus sp. nov., U. bicoloratus sp. nov., U. perthensis sp. nov., U. punctulatus sp. nov., U. quadristriolatus sp. nov., and U. bistriolatus sp. nov. Six new synonyms are proposed (senior synonyms last): U. multilineatus McKeown with U. ventralis Lea, U. dentiapicalis McKeown with U. parvus Lea, U. marginellus Hope and U. inermis Lea (not Aurivillius) with U. bivittatus Newman, U. fuscostriatus McKeown with U. lateroalbus Lea, and U. daviumbus Gressitt with U. longicornis Lea. Dorsal views of all species are presented as photographs, terminalia of both sexes illustrated, and distributions mapped. Brief comments are also given on the biology of this genus. In the full morphological phylogenetic analyses of all 39 species, I use 55 informative characters and cladistic method to test the monophylies of Uracanthus and its species groups. My results show that the monophylies of the genus and seven species groups are confirmed. However, several species groups still need additional steps to become monophyletic and are currently considered paraphyletic. In the molecular phylogenetic studies, due to the situations beyond my control (difficulties of extracting DNA from some old species and prohibitions of extracting DNA from type specimens), I analyse only 21 species. I extract and amplify the cytochrome oxidase I (COI) region of the mtDNA from 21 species and perform a phylogenetic analysis using molecular characters. To make the molecular phylogeny comparable to the morphological phylogeny, I also cladistically analyse the phylogeny of these 21 species using morphological and combined morphological-molecular characters. A comparison of trees obtained from morphological, mtDNA and combined data shows that the relationships of several closely related taxa remain constant, for example, the sister relationships of U. gigas + pseudogigas, U. insignis + punctulatus, and U. acutus + loranthi. However, the placement of U. insignis and U. punctulatus on the phylogenetic trees varies from the most basal in the full morphological analysis to the highly derived in the combined and molecular analyses. Considering the amount of available data is more limited in the molecular analysis than in the morphological analysis, the molecular phylogeny presented in this study should be interpreted with caution. The Uracanthus fauna can be divided into five subregions: the Kosciuskan, Western and Eyrean in southern and central Australia, and the Torresian and Timorian in northern Australia. The fauna are richest with highest endemism in the Kosciuskan and Western. The Kosciuskan and Western are similar in faunal composition and closely related; the Eyrean has probably acted as a faunal exchange transit area between the Kosciuskan and Western, and the two northern Australian subregions have no endemic species. When the areas of endemism of each species are attached to the phylogenetic tree generated from the full morphological analysis, a clear picture of the distribution patterns of species groups in relation to phylogeny is obtained. It is suggested that the speciation and species radiation of Uracanthus may have occurred first in the Kosciuskan, then in the Western, and finally in the Eyrean, Torresian, and Timorian.

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  • Tongan mothers' contributions to their young children's education in New Zealand = Lukuluku 'a e kau fa'ē Tonga' ki he ako 'enau fānau iiki' 'i Nu'u Sila : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education at Massey University, Palmerston North, New Zealand

    MacIntyre, Lesieli I. Kupu

    Thesis
    Massey University

    This study investigates the complex nature of how Tongan mothers in New Zealand contribute to their young children's ako (learning, and general education) in their homes, in the early childhood centre and primary school settings, and in church and the community. It argues that the mothers' contribution to their children's ako is based mainly on their cultural background, educational experience in Tonga, and their Christian faith, plus new knowledge they have picked up in New Zealand. Through the use of talanoa (conversation, questions and discussion) in Tongan and English languages, data were gathered from a small community in a town in the North Island, New Zealand and were coded, analysed, and presented. The participants draw on skills and knowledge of child-rearing strategies and educational practices experienced in Tonga before their migration to this country. However, when implemented in New Zealand, some aspects prove contradictory to the current practice in Aotearoa. The mothers find these emerging tensions frustrating, yet ongoing, but new learning in this country and their Christian faith help enhance their practice. The findings show that the mothers' use of Tongan language, cultural values, beliefs, and practices, with the lived experience of their Christian faith, is effective in teaching the children social and moral education, while contributing to their academic learning and still be preserving their Tongan culture, language, and identity. The mothers' shared use of Tongan language, cultural values and Christian faith enable them to create and maintain good relationships with teachers and other mothers for making worthwhile contributions to their children's ako in the selected contexts. Most of the mothers are involved in most activities, and nearly all participate where Tongan language is used and Tongan culture and Christianity are practised. It is acknowledged that some contributions create dilemmas and mismatches of expectations between the women and mainstream educational institutions. The women's efforts, accessing information in Tongan, and operating in education using faka-Tonga ways, and creating warm relationships among the mothers, teachers, and children who contribute to one another's learning reveal the complex nature of mothers' contributions to their children's education. They shuttle from one context to another, using their faka-Tonga ways, views and practices to fulfill their obligations and responsibilities, while going through transformation in their participation. Based on these findings, implications for mothers, teachers/educators, researchers, and policymakers are considered, and suggestions for future research directions are made that may benefit the growing Tongan population since it is they who have the main responsibility for young Tongan children's ako in Aotearoa-New Zealand.

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  • Variable rate application technology in the New Zealand aerial topdressing industry : a thesis presented in partial fulfilment of the requirements of the degree of Doctor of Philosophy in Agricultural Engineering at Massey University, New Zealand

    Murray, Robert Ian

    Thesis
    Massey University

    Greater use of technology to assist aerial application of fertiliser will be of benefit to the topdressing industry and farmers. Benefits arise through automating the fertiliser flow control system; reducing off target fertiliser application, and managing fertiliser inputs based on the potential outputs of the farmland; thus increasing the profitability of hill country farming systems. A case for technology assisted application is developed by investigating the field performance of conventional and enhanced flow control systems and the effect of variable rate application on hill country pasture production. A single particle model that predicts flight trajectory from the particle force balance based on the aircraft groundspeed, axial and tangential propeller wash, wind characteristics and particle properties including sphericity was developed. Model predictions were compared to predictions from AGDISP 8.15. Results and trends were similar. The single particle ballistics model described above was extended to predict the lateral distribution of fertiliser after release from an aircraft. To achieve this, two parameters are important, the transverse flow profile of material leaving the hopper gatebox and the sphericity of the particles. Techniques for measuring these parameters are described and experimental results are presented for superphosphate. These data were used in the model to predict the lateral distribution pattern from a Gippsland Aeronautics 200C for a known discharge mass, which was compared to a measured pattern from the same aircraft for the same discharge mass. Good agreement between the shapes of the two distributions was found. The transverse distribution model provides a practical tool for optimising the design of spreaders, or optimum particle characteristics for a given spreader. It has the ability to predict the distribution profile of any particle size distribution from each, or all, of the spreader ducts. Culmination of the single particle and transverse distribution models led to the development of a deposition footprint model that was capable of predicting field application within a 25 ha trial site. The deposition footprint model was embedded inside a geographical information system and comparisons were made between the actual and predicted deposition across a series of transect lines. Good agreement was found. Following this, a comparison of the predicted field performance between an automated and manual control system were made. Economic benefits for a single application of superphosphate were identified through using automated control, where 10% less fertiliser was applied outside of the application zone when compared to the manually operated system. This equated to a net benefit of NZD $2800 for a 1500 ha hill country farming system. The value of improving the performance of a topdressing aircraft, on an industry level, was also examined. Cost/benefit analysis between a manual and automated system revealed a benefit of NZD $111,700 yr-1 for a single topdressing aircraft using the automated system. The economic impact of Variable Rate Application Technology (VRAT) is examined, using Limestone Downs as an example. The spatially explicit decision tree modelling technique was used to predict the annual pasture production over the entire Limestone Downs property. The resulting decision tree classes tended to follow the farm's digital elevation model. A series of six different fertiliser application scenarios were developed for comparison to a base line scenario using conventional aerial application techniques. VRAT outperformed the fixed rate applications in terms of pasture production and fertiliser utilisation. Full variable rate application and a model optimised prescription map, produced the highest annual pasture yield. Variable rate techniques were predicted to increase annual production and the spatial variability of that production. An economic analysis of the six production scenarios was undertaken. Farm cash surplus was calculated for each scenario and clearly revealed the benefits of using variable rate application technology. VRAT was found to be the most efficient and highest returning application method per hectare. Additional costs and increased charge-out rates were likely to occur under VRAT; nevertheless, the analysis indicated that significant financial incentives were available to the farmer. A sensitivity analysis revealed that even with a 20% increase in charge-out rate associated with VRAT, the farm's annual cash position varied by only $4500 (0.4%), suggesting the cost of implementing such a system is not prohibitive and would allow aircraft operators to add value to their services.

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  • Studies in anaerobic/aerobic treatment of dairy shed effluent : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Agricultural Engineering at Massey University, Palmerston North, New Zealand

    Warburton, David John

    Thesis
    Massey University

    Increases in herd size and enforcement of water quality regulations have created an effluent disposal problem for the New Zealand dairy industry. Spray disposal to land and lagooning are commonly used but mechanical failures, management requirements and pressure on land have limited their suitability in many situations. This project was established to consider an alternative system. Initial studies revealed that anaerobic treatment in unmixed, non-insulated tanks, followed by trickling filter aeration, might be suitable. Two laboratory scale and one field treatment plant (1/15 - 1/20 full scale) were constructed to investigate the system. A factorial experimental design allowed investigation into three anaerobic treatment levels with a 3 x 3 aerobic treatment interaction nested within each anaerobic treatment. Anaerobic residence times of 5, 7.5 and 10 days provided loading rates of 1.35 - 0.63 kg COD/m3-day and 1.36 - 0.67 kg T S/m3-day. Removals between inlet and outlet averaged 71% and were insensitive to loading rate. Total solids accumulation rates of 40-50% TS input rate suggests that anaerobic tank design should be based on solids accumulation rate and cleaning frequency. The stone media trickling filter was loaded at approximately 0.61 kg COD/m3-day. Aeration periods of 1, 2 and 3 days and hydraulic loads of 2.8, 10.1 and 18.2 m3/m2-day were studied to determine their influence on treatment efficiency. Multiple regression analysis indicated that the longer residence times and higher recycle rates improved treatment efficiency. Removals varied with the measured parameters but ranged from 42-66% for COD. Design alterations to allow the final discharge to be taken from the bottom of the filter, after settling, would increase aerobic treatment efficiency above 75% COD removal. Prediction of treatment efficiencies beyond the monitored operating conditions suggested that only marginal improvements could be made. The TS accumulation rate in the aerobic phase was approximately 13% of the TS input rate or 56% of the BOD removal rate. Overall plant treatment efficiencies of 80-89% were obtained. Removals in excess of 92% could be achieved with minor design alterations. Maintenance and operational requirements were minimal. The only problem with the system was an average 15 fold increase in NO3-N and 4 fold increase in DIP under conditions for optimum removal of the other parameters. Intermittent land disposal could reduce this problem. Treatment comparison between similar laboratory plants, and between laboratory and field plants which varied by a scale factor of 56, suggests that identically designed plants would give a similar performance and that there is little scale effect. Increasing the scale only improved treatment efficiencies under unstable aerobic conditions, i.e., high recycle rates and low residence times. Increasing scale gave some decrease in maintenance and operational problems. Design of a full scale plant, based on daily pollution loads from a 250 cow dairy shed, suggests that the system is a viable proposition.

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  • A case study of the implementation of middle schooling in New Zealand : a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Education at Massey University, Palmerston North, New Zealand

    Brown, Margaret Anne

    Thesis
    Massey University

    This thesis considers the introduction of middle schooling to the New Zealand education system. It is a case study of a school going through the process of introducing the middle schooling concept. It seeks to identify and explain the considerable challenges that this school faced as it sought to implement this change. This research project began as a study of the factors which hinder and support the implementation of middle schooling structures and practices. It became an analysis of the features of middle schooling that make it such a challenging and problematic innovation. Middle schooling is a set of philosophical concepts, educational practices and structural arrangements for the education of students between the ages of approximately ten and fourteen years. These concepts and practices are based on the premise that students of this age have academic, social, emotional and physical needs which differ from students on either side of this age group. Middle schooling is generally understood to involve integrated curriculum which is delivered through team teaching. This approach to teaching and learning requires high levels of teacher collaboration, flexible workspaces and timetables and high levels of parental support and involvement. Ideally, middle schooling provides a separate school environment for children of this age. A number of school communities in New Zealand have gained government approval to restructure as middle schools and are at various stages in implementing this new form of schooling. The researcher began the study with the intention of developing guidelines to assist school communities to make this transition from the structures and processes of conventional schooling arrangements to those of middle schooling. To this end she initiated a programme of action research in a school that was about to introduce middle schooling arrangements for its middle years students. The innovation began to run into difficulties from an early stage and it became clear that an action research methodology was unsustainable. Instead, the researcher chose to refocus the research problem to a more analytic study of the factors that were impeding the implementation process. The research methodology evolved to that of case study. Observational data were collected in the school over two years. From these data, three factors seemed to be affecting the implementation of the middle schooling changes. These were the way in which leadership was being executed, the attitudes and responses of the teachers and the particularly complex and demanding nature of the middle schooling innovation itself. The data were then re-analysed with respect to these three factors. From this analysis, the researcher came to a number of conclusions about the relative importance and impact of these three factors. In an effort to ascertain whether the experiences of the case school were typical of the difficulties and challenges schools face when implementing middle schooling change, the case findings were cross checked against the experiences of two other schools that were five years or more into the change process. The cross checking found that the experiences of these other schools were very similar to those of the case school. All three found that implementing middle schooling change had been more difficult and demanding than any other innovation they had implemented. This study identified some aspects of leadership and teacher behaviour that may have slowed the implementation process, but these seem to have been secondary to the sheer complexity and challenges involved with this particular form of innovation. An innovation that requires such a shift in values, behaviour, structures and systems from a school community, and one that requires the sustained commitment of the entire staff over an extended period of time, will always prove to be exceptionally challenging. The case study identified five requirements that middle school implementers need to consider in order to implement the concept successfully. Failure to consider any of these requirements is likely to threaten the success of the innovation. The five requirements are: • The need to develop a shared understanding of the concept rationale and principles and how these will be operationalised within the school; • The need to develop a shared understanding of the complex, multi-faceted and integrated nature of the innovation and how this will impact on and influence the implementation process; • The need for strong, visionary, shared leadership; • The need to gain the interest and operational commitment of the entire staff and a high level of interest and commitment from the parent community and to sustain this for the life of the innovation; and • The need to develop supportive and appropriate infrastructure within the school to support the innovation.

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  • A teacher's research journey into e-learning : aligning technology, pedagogy and context : a thesis presented in prtial fulfilment of the requirements for the degree of Doctor of Philosophy in Education at Massey University, Auckland, New Zealand

    Mentis, Mandia

    Thesis
    Massey University

    e-Learning has the potential to radically change the way we teach and learn in higher education, but there is ongoing debate as to what constitutes effective e-learning environments. This study explores the interrelated areas of e-learning technology and pedagogy within the context of a postgraduate special education and educational psychology programme. The study is framed in a scholarship of teaching and learning approach and covers three successive phases of overlapping activities of teaching, learning and research. The first phase of the research focuses on the design of a community of practice approach to e-learning. The aim is to enable students to develop their identity as members of the professional community by bridging the gap between university-based learning and its real-world application. In the second phase of the research, alternative technology is used to investigate a better alignment of e-learning technology and pedagogy. The findings here show that a community of practice pedagogy is better aligned with a social constructionist e-learning technology. In the third phase of the research an e-learning alignment guide is developed to analyse the changes in e-learning in relation to the interrelated areas of technology, pedagogy and context. The guide is applied to the e-learning case studies in Phases 1 and 2 of this study. The profiles of alignment from these case studies illustrate the complexities and tensions in e-learning and the potential of linking advanced technologies with effective teaching practices to change the way we teach and learn. The key finding of this study is that careful alignment of technology, pedagogy and context is needed to actualise the potential of e-learning in higher education. The e-learning alignment guide developed in this study enables analysis of e-learning environments to provide alignment profiles. Aligning innovative technologies with appropriate pedagogies in different contexts is essential for e-learning to meet the needs of learners in the digital age. The enormous and rapid development of new educational technologies has seriously challenged traditional forms of pedagogy. This study shows that both a scholarship of teaching and learning approach and the use of the e-learning alignment guide can make a positive contribution to designing effective e-learning environments.

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  • An operational framework for improving decentralised agricultural extension : a Ghanaian case study : a thesis submitted in partial fulfilment of the requirement for the degree of Doctor of Philosophy (Ph. D.) in Agricultural Extension, Massey University, Institute of Natural Resources, Agricultural/Horticultural Systems & Management

    Okorley, Ernest

    Thesis
    Massey University

    The pressure on the public agricultural extension organisation in Ghana to improve its responsiveness to meet the needs of farmers has increased since the globalisation of trade in the early 1990s. To improve agricultural productivity and the livelihood security of farm households, the Ministry of Food and Agriculture in Ghana decentralised its extension service in 1997. Although this was a critical change in agricultural policy, the extension service has struggled to implement this policy effectively. Further improvement in the situation is hampered because there has been little research published in this area. To provide this understanding, a single-case study of a successful decentralised district level extension organisation in Ghana was used to identify the factors, processes and outcomes that contribute to its performance. The case organisation is an example of a district agricultural extension organisation that operates under a decentralisation system at the level of deconcentration, with a high farmer-to-extension agent ratio and limited and uncertain levels of Government funding. The results of the study emphasised the importance of the effects of both external and internal (or organisational) factors on the performance of the case organisation. The external factors included: (1) the political will to decentralise, (2) the level of decentralisation of other government departments, (3) the provision of a clear legal framework for decentralisation and (4) the existence of established institutions that are willing to support the decentralisation process. New external factors that were identified in this study were (1) the type and drivers of decentralisation, (2) stakeholders' willingness and commitment to support the decentralisation process and (3) the community characteristics in terms of land tenure arrangements and gender roles. The results confirmed the importance of the organisational factors prescribed in the literature: (1) stakeholder participation, (2) managerial and technical capacity, (3) operational funding and (4) accountability. However, the study also identified five other interrelated organisational factors that influenced the success of the case organisation that had not been previously reported in the literature. These included the needs to: (1) develop a needs-based extension programme, (2) expand the extension service focus and roles, (3) foster a cross-sector pluralistic extension approach (4) use needs-based groups for service delivery, and (5) extension staff attitudinal change. Multistakeholder (farmer and other organisations) participation was critical for the development of a needs-based extension programme. The case organisation had modified the traditional extension programme planning process to involve stakeholders at different levels of participation. Similarly, the case organisation involved stakeholders in its multilevel monitoring and evaluation processes. Stakeholder participation in planning and evaluation, although aimed ultimately at efficient and effective programme implementation and improvement, did enhance accountability. Because the case organisation had taken on a broader livelihood security focus to extension, the definition of farmer needs was extended to encompass on-farm and off-farm needs that have impact on the contribution agriculture makes to the livelihood security of farm households in the district. This broader livelihood security focus to extension required the case organisation to take on additional roles from those it traditionally held. In the study, a typology of such roles was developed and a role selection process used by the case organisation during its programme planning process was described. Similarly, because of this broader focus, the case organisation had to work both across sectors and with other extension providers from within the sector to meet the needs of farmers. Again, the multistakeholder programme planning process was central to fostering coordination and collaboration amongst the various extension providers in the district. Decentralisation has placed greater managerial responsibility on management staff of the case organisation. In addition, the livelihood security focus has required technical staff and attitudinal changes to develop and seek for a much broader range of skills and knowledge - meaning that the development of both managerial and technical capacity was important for the case organisation. Needs-based training, the development of a learning environment and the enhancement of staff motivation were critical for the development of staff capacity. As with other extension organisations in developing countries, the funding for the case organisation was limited and uncertain. To overcome these constraints, the case organisation had in place mechanisms to ensure its resources were used efficiently and that it could mobilise additional resources from outside the organisation. Resource efficiency was improved through an intensive monitoring system and the use of stable needs-based groups. Additional resources were mobilised by lobbying government and international donors for funds for projects that would meet the needs of farmers. Further resources were obtained through collaboration with other stakeholder organisations. Again, the multistakeholder planning process provided a platform for collaboration. Networking and special issue forums also provided mechanisms for enhancing collaboration within the district. Decentralisation was introduced into Ghana in 1997 with the aim of eventually developing a demand-driven extension system. Although viewed as successful, the case organisation has yet to achieve the level of farmer participation (i.e. self-mobilisation) that is required for a demand-driven extension system. Currently, after six years of decentralisation, the level of farmer participation can be classified as somewhere between consultation and collaboration. Therefore, the results of this study suggest that the transition from a top-down to a demand-driven extension system will take considerable time and resources.

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  • Biodegradation of cyanobacterial hepatotoxins [Dha[to the power of 7]]MC-LR and MC-LR by natural aquatic bacteria : a thesis submitted for fulfillment of the requirements for the degree of Doctor of Philosophy in Microbiology, Institute of Food, Nutrition and Human Health, College of Sciences, Massey University at Wellington, New Zealand

    Somdee, Theerasak

    Thesis
    Massey University

    The aims of this doctoral study were to: isolate naturally occurring bacteria, able to degrade microcystins (MCs), from New Zealand waterbodies; to understand the biological processes of microcystin degradation by bacteria; and to develop small scale biofilm technology for testing the effectiveness of bacteria for microcystin degradation and/or remediation. A significant amount of microcystins were required for biodegradation experiments. A modified method, using DEAE and Strata-X cartridge chromatography, was optimized for purifying microcystin variants from lyophilized bloom samples of the cyanobacterium Microcystis aeruginosa, collected en masse from Lake Horowhenua. Seven microcystin variants, MC-RR, MC-dMe-RR, MC-YR, MC-LR, [Dha7]MC-LR, MC-FR, and MC-AR were purified by chromatography and then identified by reverse-phase High Performance Liquid Chromatography (HPLC) with UV detector (UVD) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). A mixture of [Dha7]MC-LR and MC-LR, the main microcystin variants present, was used for examining biodegradation of microcystins by degrading bacteria. Three isolates of bacteria—NV-1, NV-2 and NV-3—purified from Lake Rotoiti, New Zealand were capable of degrading [Dha7]MC-LR and MC-LR. Among these isolates, NV-3 demonstrated the strongest degradative activity and was identified as a member of the genus Sphingomonas. On the basis of 16S rRNA sequencing, and 100% nucleotide sequence homology, it aligned most closely to strain MD-1. Based on the detection of two intermediate by-products (linearized peptides and a tetrapeptide) and the identification of four genes (mlrA, mlrB, mlrC and mlrD), that encode four putative proteins (enzymes) involved in microcystin degradation, it was suggested that the degradation of [Dha7]MC-LR and MC-LR by the Sphingomonas isolate NV-3 occurred by a similar mechanism previously described for Sphingomonas strain MJ-PV (ACM-3962). The bacterium Sphingomonas isolate NV-3 was examined for its ability to inhibit the growth of the cyanobacterium Microcystis aeruginosa strain SWCYNO4. It was found that the bacterium did not have any significant affect on the growth of the cyanobacterium, either by means of secretion of bacterial extracellular products or cell-to-cell contact between bacterial and cyanobacterial cells. It was established that Sphingomonas isolate NV-3 was a moderate biofilm former, based on two types of biofilm formation assays, namely, microtiter plate assays and coupon biofilm assays. This was carried out in preparation for using the bacterium in a bioreactor for biodegradation of [Dha7]MC-LR and MC-LR. The bacterium attached most effectively to ceramic, followed by PVC, polystyrene, stainless steel, and finally glass coupons. Biodegradation of MCs by the bacterium, in an internal airlift loop ceramic honeycomb support bioreactor (IAL-CHS bioreactor), was established in batch and continuous-flow experiments. In the batch experiment, NV-3 degraded a combination of [Dha7]MC-LR and MC-LR at an initial concentration of 25 µg/ml at 30 degrees C in 30 hours, whereas in the continuous-flow experiment, NV-3 degraded the same concentration of [Dha7]MC-LR and MC-LR in 36 hours with an hydraulic retention time (HRT) of 8 hours. This study has demonstrated that microcystin-degrading bacteria are present in New Zealand waterbodies and that these bacteria could be used, potentially on a larger scale, for removing microcystins from water.

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  • Pain as embodied experience : a phenomenological study of clinically inflicted pain in adult patients : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nursing at Massey University

    Madjar, Irena

    Thesis
    Massey University

    This phenomenological study describes the lived experience of pain inflicted in the context of medically prescribed treatment, explores the meanings of such pain for patients who endured it and for nurses whose actions contributed to its generation, and presents a thematic description of the phenomenon of clinically inflicted pain. The study is informed by phenomenology, both in terms of its premises and orientation, and its research design and method. The participants in the study were 14 adult patients, admitted to hospital following burn injuries, or receiving intravenous chemotherapy upon diagnosis of cancer, and 20 nurses involved in their care. Data collection took place over a period of five months and included participant observation and compilation of field notes, and a total of 89 tape-recorded interviews (48 with patients and 41 with nurses). Through the process of hermeneutic interpretation a number of themes were identified and used to describe the phenomenon of clinically inflicted pain and the structure of the lived experience of the patients and nurses concerned. The phenomenon of clinically inflicted pain is described in terms of four related themes: 1) the hurt and painfulness of inflicted pain; 2) handing one's body over to others; 3) the expectation and experience of being wounded, and 4) restraining the body and the voice. These themes point to the embodied nature of pain experience and the extent to which the person is involved not only in the enduring of pain but also in its generation. The broader lifeworld of clinically inflicted pain involves patients in the experience of constituting such pain, often as punishment and almost always as something unavoidable, and in turn being constituted by their experiences in terms of losing and seeking to regain a sense of embodied self and of personal situation, and by changed experiences of lived space and lived time. Nurses who themselves helped to generate pain, frequently overlooked the patient's lived exerience and thus the essential nature of inflicted pain as painful, wounding, and demanding cooperation and composure from the patient. Instead, the pain frequently became invisible to nurses involved in its infliction, or when it could not be overlooked or ignored, it was perceived as inevitable, non-harmful, and even as beneficial to patients' recovery. The strategic responses that nurses adopted to pain infliction included detachment from the perceived impact and consequences of their own actions and objectification of the person in pain as a body-object on whom certain tasks had to be performed. An alternative to the strategy of detachment and objectification was involvement in a therapeutic partnership between the nurse and the patient, where shared control over pain infliction and relief helped to sustain trust in the relationship and preserve personal integrity of the patient and the nurse. The study points to dangers for both patients and nurses when clinically inflicted pain is ignored, overlooked, or treated with detachment. It also points a way toward nursing practice that is guided by thoughtfulness and sensitivity to patients' lived experience, and awareness of freedom and responsibility inherent in nursing actions, including those involved in inflicting and relieving pain. The study raises questions about nurses' knowledge, attitudes, and actions in relation to clinically inflicted pain, and highlights the need for nursing education and practice to consider the contribution of a phenomenological perspective to the understanding of human experience of pain, and the nursing role in its generation, prevention, and relief.

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  • Oxygen and the ovarian follicle : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Bioprocess Engineering at Massey University, Palmerston North, New Zealand

    Redding, Gabe Peter

    Thesis
    Massey University

    The role oxygen plays in the developing ovarian follicle is of interest not only to the field of developmental biology but also to in-vitro fertilisation (IVF) technologists, as oxygenation of the oocyte is considered to be a potential determinant of oocyte competence. Oxygen transport through the developing ovarian follicle, and practical aspects of the analysis of oxygen in human follicular fluid were investigated in this work. Mathematical modelling of oxygen transport in the pre-antral, and antrallpreovulatory follicle revealed a number of interesting findings, Contrary to previous conclusions (Gosden & Byatt-Smith, 1986), oxygen can reach the oocyte in the small pre-antral follicle. Improved estimates of diffusion coefficients through the granulosa cell layer and the inclusion of fluid voidage in this layer showed that oxygen can also reach the oocyte in large pre-antral follicles. The amount of oxygen that reaches the oocyte in the pre-antral follicle is a function of its size and degree of vascularisation. Symmetrically distributed vascularisation is superior in achieving a well oxygenated follicle. However, the large pre-antral follicle will eventually reach a size beyond which it cannot grow without anoxic regions developing. The size at which this occurs is consistent with the size at which antrum formation is observed in human follicles. The model predicts that the follicle can avoid an anoxic state through antrum formation, and shows that the follicle develops in a way that is consistent with overcoming mass transport limitations. The oxygen status of the follicle during the antrallpre-ovulatory phase of growth requires that the volume of granulosa cells be balanced by the volume of follicular fluid. Further predictions suggest that oocyte respiration becomes sub-maximal at follicular fluid volumes below approximately 4m1, vascularisation levels below 38%, or fluid i dissolved oxygen levels below 5.1 ~01%. These values are consistent with observations in the literature. It was also shown that the measurement of follicular fluid dissolved oxygen levels could provide a simple measure of the respiratory status of the oocyte, and this may be superior to the measurement of follicular vascularisation which requires knowledge of more parameters. Methodology for the analysis of follicular fluid oxygen solubility and diffusivity was developed using a Clark oxygen electrode. Analysis of these parameters showed that they are similar to human plasma, and allowed the predictive uncertainty of the model to be reduced. Experimental studies into the effects of IVF aspiration on follicular fluid were carried out. Aspiration results in significant changes in the properties of follicular fluid. Dissolved oxygen levels rose 5 * 2 vol%, pH increased by 0.04 * 0.01 pH units, and temperature dropped by 7.7 * 1.3 "C. Mathematical modelling of blood contaminated follicular fluid also showed that contamination results in significant changes in the dissolved oxygen of the fluid. This suggests that if the composition of follicular fluid is to be determined (particularly dissolved oxygen), sampling andlor measurement of fluid must take place before the collection vial of the aspiration kit, and blood contamination must be eliminated. Based on this result, the design and testing of devices capable of reliable sampling andlor rneasurement of oxygen levels of follicular fluid was considered. This presents a continuing challenge, including the integration of routine follicular fluid oxygen measurement into clinical practice.

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  • Epidemiology of epilepsy in Tasmania : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Epidemiology at Massey University, Wellington, New Zealand

    D'Souza, Wendyl Jude

    Thesis
    Massey University

    Background Better understanding of the demographic distribution of epilepsy and the prevalence of 'more specific forms of epilepsy' in community-based settings would improve our understanding of this disorder at the population level . Although we now have good estimates of epilepsy prevalence for most countries, we still lack knowledge on its demographic distribution by age, ethnicity, region, and socioeconomic status. In addition, no studies to date have reported the prevalence of epilepsy syndromes using patient interview outside a hospital setting. This thesis provides the first community-based estimates of the prevalence of the most common clinical group of epilepsies presumed to have a genetic basis - The Idiopathic Generalised Epilepsies (IGE) - by patient and witness interview. Methods This thesis has involved conducting five pieces of new research: (i) a series of reviews and analyses of descriptive data on epilepsy prevalence, particularly focusing on the critical methodological issues of ascertainment, diagnosis and classification of epilepsy for epidemiological purposes; (ii) the validation of a modified diagnostic epilepsy questionnaire adapted for administration in population studies; (iii) recruitment of a community-based cohort - The Tasmanian Epilepsy Register (TER) - through the Australian national prescription database; (iv) estimation of the overall prevalence and distribution of self-reported treated epilepsy in Tasmania by imputation methods; (v) estimation of the prevalence and distribution of IGE in Tasmania by telephone interviewing. Results My modified diagnostic questionnaire, administered by telephone interviewing and interpreted with standardized guidelines, demonstrated excellent agreement with an epilepsy specialist's clinical assessment in diagnosing the presence of epilepsy (K = 0.94), seizure-onset types (K = 0.84), simple or complex partial seizures (K=0. 87), any generalized non-convulsive seizure (K=0.82), and IGE (K = 0.82). A lthough stil l substantial, agreement was not as close for secondarily general ized seizures (K = 0.74), and generalized tonic-clonic seizures (K = 0.79). 7541 patients treated with antiepileptic drugs (AEDs) in the preceding year in Tasman ia were eligible for recruitment through the Australian national prescription database. After three mail contacts, 54.0% responded, with 43.6% who indicated treatment for epilepsy representing 86.0% of total possible epilepsy cases by imputation (n=2063) in Tasmania. 1180 agreed to participate in the TER, 90.0% of participants received their AEDs either exclusively from their general practitioner (70.9%) or in combination with a medical specialist (19.1%) in the preceding twelve months. The adjusted treated epilepsy prevalence was 4.36 per 1000 (95% CI 4.34, 4.39); this was: lower in women (prevalence ratio 0.92 (95% CI 0.84, 1.00); greater with increasing age (p< 0.001 ); similar in the three main geographical regions; and similar by categories of socioeconomic status based on postcode of residence. Following enrolment, 959/1083 (88.6%) eligible TER participants completed the diagnostic telephone interviewing, with partial epilepsy classified in two thirds, and generalised epilepsy in slightly more than one-fifth. IGE was observed in 20.3%, with tonic-clonic seizures (17.03%) and the absence epilepsies combined (11.01 %) being the most common IGE seizure types and syndromes respectively. The estimated prevalence of IGE was 0.89 per 1000; is highest between the ages of 20-39 years and in females, but was similar between Tasmanian regions and socio-economic groups. IGE prevalence beyond childhood related to refractory childhood or adolescent disease rather than olderonset cases, and was characterised by the presence of myoclonic and tonic-clonic seizures. Generalised seizures, but not IGE, were less prevalent in southern Tasmania. Conclusions Utilising the design approach described in this thesis may provide an alternative to neurological assessment, and when coupled with case ascertainment through prescription data, can provide a valid estimate of the prevalence of 'more specific forms of epilepsy' in countries with high access to health services. The observed pattern of high elderly epilepsy prevalence, is similar to patterns in recent studies in other developed countries, and has important implications for future planning of health services in these countries. IGE represents a considerable proportion of community-treated disease with important aetiological and prognostic determinants occurring at the seizure rather than syndrome level of classification.

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  • Regulation of sulfur assimilation in onion (Allium cepa L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Physiology at Massey University, Palmerston North, New Zealand

    Thomas, Ludivine A.

    Thesis
    Massey University

    Onion (Allium cepa L.) is an example of a species that accumulates very high levels of reduced sulfur (S)-containing compounds, particularly in the bulb as alk(en)yl-L-cysteine-sulfoxides (ACSOs) and it is these compounds, or their derivatives, that confers the distinct odour and pungent flavour. In common with higher plants, the S assimilation pathway in onion begins with the activation of uptaken sulfate (SO4 2-) to 5'-adenylylsulfate (APS), a reaction catalysed by ATP sulfurylase (ATPS; EC 2.7.7.4). Then, APS is reduced to sulfide (S2-) in a two-step process catalysed by the enzymes APS reductase (APSR; EC 1.8.4.9) and sulfite reductase (SiR; EC 1.8.7.1). To complete the reductive assimilation pathway, S2- is incorporated into the amino acid skeleton of O-acetylserine (OAS) to form cysteine, and this reaction is catalyzed by OAS (thiol)-lyase (OAS-TL; EC 4.2.99.8). While the regulation of the pathway is quite well defined in the plant model Arabidopsis, much less is known about its regulation in S accumulating species such as onion. The primary aim of this thesis, therefore, was to characterise the enzymes of the S assimilation pathway in onion, with a particular emphasis on ATPS. As part of this charaterisation two genotypes of onion were compared. These comprised a mild genotype, 'Texas Grano 438' (TG) with a lower level of S-containing compounds in the bulb tissues, and 'W202A' (W), a cultivar with a higher level of S containing compounds in the bulb tissues. As well, comparisons were made between seedlings (typically harvested at 7 weeks) and plants at a designated mature stage (at bulbing; typically after 4 months growth), and for plants grown in S-sufficient (S+) media or S-deficicnt (S-) media, as appropriate. In terms of plant growth, S-deprivation generally had a negative influence for both genotypes, with significant reductions in total biomass (measured as fresh weight) for TG at both the seedlings and mature stages. ATPS activity and accumulation were shown to be present in all tissues examined (leaf, root, bulb) as well as the chloroplasts, with highest activity measured in the roots, particularly in seedlings. ATPS activity and accumulation were also compared between the two genotypes (TG and W) with ATPS activity and accumulation higher in W, particularly at the seedling stage. In terms of the influence of S supply, in general higher ATPS activity was measured in chloroplast, leaf and root extracts from plants of both genotypes grown in the S- media, at the seedling stage. In roots of mature plants of both genotypes, a significant increase in activity was measured in response to S-deprivation, while in chloroplasts isolated from mature plants of both genotypes, highest activity was measure in those grown in the S+ media. Finally diurnal variations were observed in chloroplast, leaf and root extracts of both genotypes with a general trend of an increase in ATPS activity and accumulation a few hours after illumination and upon the onset of the dark period. Although a single gene coding for ATPS is presumed to be present in onion, the enzyme was characterized as two electrophoretic forms using 1D-PAGE during western analyses following fractionation of chloroplasts by anion exchange chromatography and also as an alignment of spots using 2D-PAGE. As protease inhibitors were routinely included in the extraction buffers, these forms suggest the occurrence of ATPS isoforms that may arise as a consequence of post-translational modifications. The regulation of ATPS by one mechanism of post-translational modification, phosphorylation, was therefore investigated using several techniques including the detection of a shift in molecular mass, a change in enzyme activity or pI (as determined by 2D-PAGE) and the capability to bind to 14-3-3 proteins using affinity chromatography. Following treatments of chloroplast extracts to promote either the phosphorylation (P+) or the dephosphorylation (P-) of proteins, no molecular mass change or change in activity was observed. However, after fractionation by 2D-PAGE, differences in the spot alignment of ATPS were visualized, suggesting that ATPS is a phosphoprotein. The enzyme was detected in pull-downs after affinity chromatography, suggesting that ATPS may also interact with 14-3-3 proteins (although this needs to be confirmed unequivocally). A model is advanced, therefore, in which upon phosphorylation, no variation in ATPS activity occurs but a change in the surface charged and possibly a change in conformation of the protein does occur to make the enzyme competent to interact with 14-3-3 proteins.

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  • Behaviour of milk protein-stabilized oil-in-water emulsions in simulated physiological fluids : 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

    Sarkar, Anwesha

    Thesis
    Massey University

    Emulsions form a major part of processed food formulations, either being the end products in themselves or as parts of a more complex food system. For the past few decades, colloid scientists have focussed mainly on the effects of processing conditions (e.g. heat, high pressure, and shear) on the physicochemical properties of emulsions (e.g. viscosity, droplet size distribution and phase stability). However, the information about the behaviour of food structures post consumption is very limited. Fundamental knowledge of how the food structures behave in the mouth is critical, as these oral interactions of food components influence the common sensorial perceptions (e.g. creaminess, smoothness) and the release of fat-soluble flavours. Initial studies also suggest that the breakdown of emulsions in the gastrointestinal tract and the generated interfacial structures impact lipid digestion, which can consequently influence post-prandial metabolic responses. This area of research needs to be intensively investigated before the knowledge can be applied to rational design of healthier food structures that could modulate the rate of lipid metabolism, bioavailability of nutrients, and also help in providing targeted delivery of flavour molecules and/or bioactive components. Hence, the objective of this research was to gain understanding of how emulsions behave during their passage through the gastrointestinal tract. In vitro digestion models that mimic the physicochemical processes and biological conditions in the mouth and gastrointestinal tract were successfully employed. Behaviour of model protein-stabilized emulsions (both positively charged (lactoferrin) as well as negatively charged [β-lactoglobulin (β-lg)] oil-in-water emulsions) at each step of simulated physiological processing (using model oral, gastric and duodenal fluids individually) were investigated. In simulated mouth conditions, oil-in-water emulsions stabilized by lactoferrin or β-lg at the interfacial layers were mixed with artificial saliva at neutral pH that contained a range of mucin concentrations and salts. The β-lg emulsions did not interact with the artificial saliva due to the dominant repulsion between mutually opposite charges of anionic mucin and anionic β-lg interfacial layer at neutral pH. However, β-lg emulsions underwent some depletion flocculation on addition of higher concentrations of mucin due to the presence of unadsorbed mucin molecules in the continuous phase. In contrast, positively charged lactoferrin emulsions showed considerable salt-induced aggregation in the presence of salts (from the saliva) alone. Furthermore, lactoferrin emulsions underwent bridging flocculation because of electrostatic binding of anionic mucin to the positively charged lactoferrin-stabilized emulsion droplets. In acidic pH conditions (pH 1.2) of the simulated gastric fluid (SGF), both protein-stabilized emulsions were positively charged. Addition of pepsin resulted in extensive droplet flocculation in both emulsions with a greater extent of droplet instability in lactoferrin emulsions. Coalescence of the droplets was observed as a result of peptic hydrolysis of the interfacial protein layers. Conditions such as ionic strength, pH and exposure to mucin were shown to significantly influence the rate of hydrolysis of β-lg-stabilized emulsion by pepsin. Addition of simulated intestinal fluid (SIF) containing physiological concentrations of bile salts to the emulsions showed competitive interfacial displacement of β-lg by bile salts. In the case of lactoferrin-stabilized emulsion droplets, there was considerable aggregation in the presence of intestinal electrolytes alone (without added bile salts) at pH 7.5. Binding of anionic bile salts to cationic interfacial lactoferrin layer resulted in re-stabilization of salt-aggregated lactoferrin emulsions. On mixing with physiological concentrations of pancreatin (mixture of pancreatic lipase, amylase and protease), significant degree of coalescence and fatty acid release occurred for both the emulsions. This was attributed to the interfacial proteolysis by trypsin (proteolytic fractions of pancreatin) resulting in interfacial film rupturing. Exchange of initial interfacial materials by bile salts and trypsin-induced film breakage enhanced the potential for lipolytic fractions of pancreatin to act on the hydrophobic lipid core. The lipid digestion products (free fatty acids and mono and/or diglycerides) generated at the droplet surface further removed the residual intact protein layers from the interface by competitive displacement mechanisms. The sequential treatment of the cationic and anionic emulsions with artificial saliva, SGF and SIF, respectively, was determined to understand the impact of initial protein type during complete physiological processing from mouth to intestine. Broadly, both the protein-stabilized emulsions underwent charge reversals, extensive droplet flocculation, and significant coalescence as they passed through various stages of the in vitro digestion conditions. Except in the simulated mouth environment, the initial charge of the emulsifiers had relatively limited influence on droplet behaviour during the simulated digestion. The results contribute to the knowledge of how structure and charge of the emulsified lipid droplets impact digestion at various stages of physiology. This information might have important consequences for developing suitable microstructures that allow controlled breakdown of droplets in the mouth and predictable release of lipids in the gastrointestinal tract.

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  • Effects of willow (Salix spp.) browse upon ewe reproduction and rumen microbiology under drought feeding conditions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand

    Pitta, Dipti Wilhelmina

    Thesis
    Massey University

    A series of grazing experiments were conducted in the summer/autumn of 2003 and 2004 at Massey University's Riverside dryland farm near Masterton in Wairarapa on the East Coast of NZ, to study the effects of grazing willow fodder blocks (6,000 stems/ha) upon the production and reproductive performance of ewes relative to ewes grazing drought pastures. Drought pastures were simulated in this study and included short drought pasture and long drought pasture. Pasture with a low pre-grazing mass of approximately 1500 kg OM/ha, a dead matter content of >50 % and a sward height of 5-7 cm was defined as short drought pasture typical of drought conditions. Long drought pasture was similar to pasture growing in the willow fodder blocks, with a pre-grazing pasture mass of >4000 kg OM/ha, a sward height of > 30cm and a dead matter content of 30-60 % . Willow fodder blocks were established on low-lying wet, marshy areas of the farm that had very low or zero productivity in the undeveloped state. Pasture development in the fodder blocks was noticed with the growth of unsown grasses and legumes, as the areas dried up following the planting of willow stakes, due to evapotranspiration from the trees. Forage in the willow fodder blocks included both trees and pasture that was grown under the trees. The nutritive value of short drought pasture was low with an ME of 8 MJ/kg O M ; long drought pasture ranged between 8- 1 0 MJ ME/kg DM; willow pasture contained 8 MJ M Elkg DM in 2003 and 1 0 MJ ME/kg OM in 2004. The nutritive value of edible willow tree ( 10 MJ/kg OM. The concentrations of the secondary compounds such as condensed tannins (CT ; 30- 40 glkg OM) and phenolicglycosides ( PG ; 1 5-35 g/kg DM) were higher in willow trees compared to their concentrations (CT ; 2-3 g/kg DM) and (PG; 2-9 g/kg OM) in control drought pastures. Experiments involving short drought pasture, long drought pasture and willow fodder blocks as treatment groups were grazed by ewes for 10 weeks in regular breaks from mid February to early May. Ewes were mated during this period and were joined together after mating and grazed on normal pasture until weaning. Live weight (LW) change and body condition score (BCS) were recorded throughout the experiments, whilst reproductive performance of ewes was measured as the number of lambs recorded at ultrasound pregnancy scanning, lambing, docking and weaning. Measurements on wool production were also recorded at weaning. In 2003, experimental ewes grazed control drought pastures (short and long) and willow fodder blocks (restricted and full access) as treatment groups (n= 1 00 ewes/group; Chapter 2). Ewes grazing short drought pasture had an allowance of 0.8 k g DM/ewe/d whilst ewes with restricted access had an allowance of 0.8 kg DM/ewe/d from drought pasture and 0 .4 kg OM/ewe/d from willow fodder blocks. Ewes in full access treatment group had no access to pasture but were confined to willow fodder blocks at an allowance of 2.0 kg OM/ewe/d, which was the same allowance given to long drought pasture ewes. Ewes grazing short drought pasture lost weight at approximately 1 00g/d and recorded a low reproductive rate (90 lambs weaned/100 ewes mated) with a high proportion of single lamb births. Live weight loss was significantly reduced to 40 g/d in ewes grazing willow fodder blocks (full access) with a 20% units increase in reproductive rate due to more multiple births (P <0 .05) in w illow supplemented ewes than control ewes. It was concluded that the increased reproductive rate from willow supplementation in ewes grazing drought pasture might be partly explained by reduced body protein catabolism, besides also increasing plasma branched chain amino acids CBCAA) and essential amino acids (EAA) concentrations. To investigate the effects of willow supplementation on rumen microbes, rumen samples were collected during the 2005 experiment with fistulated ewes over a 10 week period. The study involved the use of a molecular technique ( Chapter 5), denaturing gradient gel electrophoresis (DGGE), to compare the rumen microbial populations between the control and supplemented ewes and a cultivation technique (Chapter 6) to study the effect on rumen bacteria of ewes grazing drought pastures with and with out willow supplementation. DGGE analysis of the V3 region of 16S ribosomal RNA genes in DNA extracted from samples of rumen contents taken fortnightly over a 10 week feeding period showed a distinct difference in banding patterns between treatment groups which progressively developed over time, showing rumen microbial adaptation to willow supplementation. However, phylogenetic analysis of the DNA sequences retrieved from the DGGE bands from willow-supplemented and control ewes did not cluster by treatment group. It was deduced that willow supplementation induced a change in rumen bacterial populations through selecting sub-populations of organisms already present in the rumen. The changes in the rumen bacterial populations is attributed to the ability of these bacteria to metabolise secondary compounds in willow such as phenolicglycosides and flavanoid monomers and their ability to resist the inhibitory effects of condensed tannins. The cultivation study involved enumeration, isolation and purification of bacterial colonies on Complete Carbohydrate, Salicin, Xylan, Cellulose and Willow media followed by full characterisation of a representative set of pure bacterial cultures. Total bacterial counts on the above media at week 5 and week 10 were generally lower in willow-supplemented ewes compared to control ewes and the 16S rRNA gene sequences of the majority of iso lates characterised from both Salicin and Xylan media, were most closely related to species from the Pseudobutyrivibrio genus. Isolates from Willow medium clustered as two distinct groups. One group (mostly isolated from control ewes) was made up of mainly of organisms not usually associated with the rumen and probably represent non-resident organisms that are passing through the rumen. The other group of bacteria were mainly retrieved from willow-supplemented ewes and were most closely related to species of the Ofsenella genus. Compared to bacteria isolated on Salicin and Xylan media, isolates on Willow medium showed little ability to ferment various carbohydrates or trypticase (hydrolysed protein) but were able to utilise secondary compounds from willow. It was concluded that willow fodder blocks are useful sources of supplementary fodder for mating ewes during drought situations. Both the field and m icrobiological studies showed adaptation to the willow supplementary diet, including the detection of Olsenelfa-like bacteria for the first time in the rumen. It is suggested that the principal purpose of the rumen investigation is the degradation of secondary compounds present in willow.

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