Restricted Theses and Dissertations

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The electronic full-text versions of theses and dissertations in this collection are not publically viewable. In most cases the full-text is viewable only by current Lincoln University staff and students. See the item record of each thesis or dissertation for a description of access rights.

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    Towards the development of a management information system for glasshouse tomato growers : A thesis submitted in partial fulfilment of the requirements for the degree of Master of Horticultural Science
    (Lincoln College, University of Canterbury, 1982) Lewis, Ian Raymond
    Since the early seventies, glasshouse tomato growers have faced severe cost-price pressures due mainly to the sharply increased cost of heating oil. If growers are to maintain or improve their profitability, on-property changes need to take place to increase yield and returns and/or reduce costs. Formal management information systems (MISs) are interpreted as a basis for assisting growers in their decision making, including the evaluation of alternative strategies. The development and use of MISs was considered using an interdisciplinary approach and drawing upon the experiences of non-agricultural firms and MISs that have been successfully developed for glasshouse cropping firms. Key factors to success were identified. A computer based "mail in" MIS was developed with a group of Auckland glasshouse tomato growers selected for their economic motivation and common information requirements. The MIS was developed closely with growers to determine their information requirements, the scope of the system, the recording of data and input/output form design. A horticultural advisory officer (HAO) from the Ministry of Agriculture and Fisheries (MAF) collected grower data for processing and helped growers interpret and effectively use the new information in their decision making. After two seasons operation, the MIS was evaluated by the growers and the HAO. The MIS project was successful from a number of aspects. Improvements were also suggested, particularly in relation to the design of the output form and the role performed by the HAO. If the HAO had carried out more timely and frequent data collection and interpretation, it was likely that growers would have seen a greater use within the season for information provided by the MIS. The evaluation also highlighted growers' limited perception of the systems over which they have control. seen as an area for discussion between the HAO and the grower. To meet the likely demand for formal planning models within the MIS in the future, an assessment was made of the feasibility of developing a bio-technical simulation model of the glasshouse tomato production system. Temperature was identified as the main factor influencing tomato plant response in New Zealand. A glasshouse climate sub-model based on regression equations was developed to predict daily glasshouse minimum and maximum temperatures using external weather data as input to the model. A glasshouse tomato crop sub-model was developed to predict the date of harvest onset, the pattern of yield throughout the season and total yield using temperature data as input to the model. Ontario heat units were used as a time course for the model and as an indicator of tomato plant response. A harvest threshold of 2206 Ontario units was more effective than calendar days in predicting harvest onset. The model was validated. Crop yield was successfully modelled using Ontario units and regression analysis. The model was validated. However this basic model was only applicable to well managed crops. Factors reducing the yield potential need to be incorporated into the model to broaden its applicability. Other suggestions are made to improve the usefulness of the model. The simulation model can be used by itself or linked with an economic model to compare alternative strategies between seasons or to predict crop development and production part-way through a season using actual weather data, likely future weather and details of any factors reducing yield potential. The future development and use of MISs are discussed.
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    A rough-turbulent Froude law physical hydraulic model of the Waiho alluvial fan head: A dissertation submitted in partial fulfilment of the requirements of the degree of Master of Engineering (Natural Resources) at Lincoln University
    (Lincoln University, 2001) Jolly, Frederic Tom
    Located at the head of the Waiho alluvial fan, Wetland, New Zealand is the township of Franz Josef Glacier. Aggradation of this region of the Waiho alluvial fan has been occurring for much of this century, and as a consequence, the Waiho River now presents a significant natural hazard for the Franz Josef Glacier community. Intrinsic to the process of aggradation occurring on the Waiho alluvial fan head, is the inability of the Waiho River to transport sediment, and more specifically bedload. A 1: 100 scale, rough-turbulent Froude law physical hydraulic model of the Waiho alluvial fan head is developed to gain some insight into the potential bedload transport capacity of three steady flows across this region of the fan. In addition, an assessment of the validity of the use of the Schoklitsch (1962), cited in Young and Davies (1990) and Bagnold (1980) bedload transport capacity equations for predicting sediment transport on the Waiho alluvial fan proximal region is undertaken. Although there are limited prototype validation data available, similarity between the model and its prototype is shown to be achievable at the design scale of 1: 100. In the context of this study as a preliminary to further research, it is therefore considered that the representation of the prototype is sufficient to allow scaling of the results obtained at the design scale, to the prototype situation. Difficulties experienced with uncontrolled variations in the sediment feed rates to the model limited the accuracy of the measured bedload transport capacities to a range of values. The range of potential bedload transport capacities that would be expected on the proximal region of the Waiho alluvial fan, for the four year return period, annual return period, and the 500 m³s⁻¹ flood flows are determined to be 2160 - 2270 kgs⁻¹ , 1870 - 2080 kgs⁻¹, and 790 - 930 kgs⁻¹ respectively. The form of both bedload transport capacity equations investigated is found to be incorrect for application to the Waiho alluvial fan proximal region modelled here. It is concluded that the use of the Schoklitsch (1962), cited in Young and Davies ( 1990), equation is not valid for the prediction of bedload transport capacities on the Waiho alluvial fan proximal region. The Bagnold (1980) equation demonstrated potential for its use for the prediction of bedload transport capacities on the Waiho alluvial fan proximal region. However, given the limited measured bedload transport capacities for comparison, further research is required to allow a more comprehensive validation of the Bagnold (1980) equation.
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    The tissue distribution of ovine glucose transporter RNA : A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science, Lincoln University
    (Lincoln University, 1995) Craigen, Mary Clare Tracey
    The control of nutrient partitioning between tissues in an animal is of importance since it determines the potential of tissues to perform their particular functions. Various nutrient partitioning agents, such as insulin, GH and IGF-I have been identified and their partitioning effects have been extensively investigated. Glucose has been identified as one of the most important metabolites that is regulated by these partitioning agents. For example, the entry of glucose into cells is highly controlled by a family of glucose transporters which have tissue-specific distribution. Several research groups have proposed that nutrient partitioning agents regulate nutrient partitioning by acting directly or indirectly on the glucose transporters. To investigate the nutrient partitioning effects of GH, a trial was set up with 64 sheep genetically selected for either slow or fast glucose clearance. It has previously been shown that these animals exhibit altered nutrient partitioning such that animals from the slow glucose clearance line are leaner than animals from the fast glucose clearance line. A GH peptide vaccine was administered to 16 animals from the slow and to 16 animals from the fast glucose clearance line. The other animals were controls ( 16 slow and 16 fast glucose clearance respectively). After 5 months the animals were slaughtered and samples taken for analysis of carcass and non-carcass composition, pH, tenderness, and RNA distribution between tissues. Physiological and biochemical data indicated that there was no significant effect of the GH peptide on partitioning of nutrients between adipose and muscle tissues over the experimental period. Growth rate and insulin sensitivity were not affected by the administration of the GH peptide. A Growth Hormone Releasing Hormone (GRF) challenge increased circulatory GH in all animals, but there was no additional effect of the GH peptide on this challenge. A qualitative study of the distribution of glucose transporters in animals from the two selection lines was undertaken. Southern blot analysis illustrated that sheep possessed the genes for at least 4 glucose transporters. A PCR amplification of a portion of exon 11 of ovine GLUT4 produced a 329 nucleotide product which was sequenced. 84% homology occurred between human and ovine GLUT4 in this region. Northern blot analysis (with human cDNA glucose transporter probes) showed that GLUTl was present in brain, skin and muscle, GLUT2 in small intestines, GLUT3 in brain and GLUT4 in small intestines. Apart from the GLUT4 result, this pattern of distribution in the sheep is similar to the pattern observed in humans, rats, mice and cows. A novel ovine GLUTl probe was also used to examine the samples and showed that GLUTl was predominantly located in ovine brain, and that skin and adipose tissues expressed substantially less GLUTl. The distribution of glucose transporters in the ovine was shown to be similar to that of the bovine. Both patterns share some similarities with the human distribution pattern. A model was proposed in which GLUTl and GLUT4 levels in adipose and muscle tissues could account for the altered nutrient partitioning previously shown in the two lines of sheep selected on glucose clearance.
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    Measurement of fat synthesis in sheep : A thesis submitted in partial fulfilment of the requirements for the degree of Master of Agricultural Science in the University of Canterbury [Lincoln College]
    (Lincoln College, University of Canterbury, 1986) Davey, Helen Winsome
    The in vivo rate of fat synthesis in ovine adipose tissue was estimated by measuring the rate of incorporation of radioactive plasma glucose into adipose tissue glyceride glycerol during a continuous intravenous infusion of [U- ¹⁴C]-glucose. Adipose tissue samples were removed from a back fat site using local anaesthesia or immediately following slaughter. The rate of incorporation of ¹⁴C radioactivity into glyceride glycerol was linear for at least 24 hours and was used to calculate the rate of incorporation of plasma glucose into adipose tissue glyceride glycerol. In two experiments (Sheep 1 and 2) , the rates were 0.41 and 1.32 nmol glucose min⁻¹g back fat⁻¹. Assuming that plasma glucose was the only source of glycerol 3-phosphate, that there was no partial hydrolysis of triglycerides with subsequent re-esterification of fatty acids and that the rate of incorporation of plasma glucose into back fat adipose tissue was the same as into total body adipose tissue then the rates of glucose incorporation into adipose tissue glyceride glycerol were equivalent to 14 and 28 grams of adipose tissue synthesized per day. The turnovers of glucose in the respective experiments were 24 and 39 µmol glucose min⁻¹ kg-⁰⁷⁵ . Thus, adipose tissue glyceride glycerol synthesis accounted for one and two percent of glucose turnover. Glucose utilization for fatty acid synthesis in Sheep 2 was less than one percent of the glucose turnover. In 24 week old lambs which were either weaned, suckled, weaned and infused with exogenous insulin or suckled and infused with exogenous insulin. the same method of infusing [U- ¹⁴C]-glucose continuously and sampling adipose tissue was used to determine the rates of glucose incorporation into glyceride glycerol. The rates ranged from 0.7 to 4 .5 nmol glucose min⁻¹ g adipose tissue⁻¹-. The mean rate of incorporation of glucose into back fat glyceride glycerol was 1.87 nmol min⁻¹ g tissue⁻¹ (17.7 µmol glucose min⁻¹ lamb⁻¹) which is equivalent to 54 grams of adipose tissue synthesized per day. There were no significant differences between the treatment groups in the rates of glucose incorporation into total body fat glyceride glycerol. The rate of incorporation of glucose into fatty acids, however , was significantly greater in the lambs infused with insulin than those receiving no exogenous insulin infusion (89 and 20 µmol min⁻¹ lamb⁻¹ respectively) . Euglycaemic insulin clamps were used to examine the effect of insulin on the in vivo rate of fat synthesis in four lambs. In these experiments [U- ¹⁴C ) glucose and insulin were infused continuously and the rate of an intravenous infusion of dextrose varied to maintain the plasma glucose concentration at 3 .6 mM. The plasma insulin concentration was 14 ± 2 μU cm ⁻³ during the first 8 hours (period 1) and 160 ± 9 μU cm ⁻³ μU cm ⁻³ during the second 8 hours (period 2). The rates of incorporation of glucose into glyceride glycerol were 1.84 and 4.00 nmol min⁻¹ g back fat⁻¹ in periods 1 and 2 respectively. These rates are equivalent to 53 and 117 grams of adipose tissue synthesized per day . The glucose turnover was 40 μmol min⁻¹ kg-0. 75 during period 1 and 88 μmol min⁻¹ kg-⁰⁷⁵ during period 2. A constant three percent of glucose turnover was used for glyceride glycerol synthesis. Glucose utilization for fatty acid synthesis increased from one to two percent of glucose turnover on progressing from period 1 to period 2. A new method for measuring fat synthesis is described in this thesis. The method provides direct evidence that insulin stimulates fat synthesis in vivo, and demonstrates that a very small proportion of glucose turnover is used for fat synthesis in sheep.
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    The water flow and building behaviour of a small alluvial fan : A thesis submitted in partial fulfilment of the requirements for the degree of Master of Applied Science at Lincoln University
    (Lincoln University, 1992) Striaght, B.
    A small alluvial fan was built with a constant rate of input of water and sediment. The fan surface was measured at half hour intervals from the eleventh to the thirty fifth hour of accumulation and the area affected by flow during the previous half hour described and recorded. Flow behaviour was examined at two scales: the long term scale where flow is responsible for the production of the gross fan morphology and the short term scale associated with the formation of surface features on the fan. The long term hydraulic form of the fan is described quantitatively. The form is constant despite infiltration of flow into the fan surface. This consistency in long term hydraulic form allows a simple transformation of fans to a common volume, and hence common surface area, to enable records of flow occurrence on fans of different size to be compiled in to a description of long term flow behaviour. This long term flow behaviour is described quantitatively. It shows a division between behaviour associated with channelised flow and the surface flows which spread out from these channels. An empirical long tern flow model incorporating infiltration appears to provide an accurate description of long term flow behaviour but short term variation precluded statistical validation. Despite this imprecision it is inferred that the long term flow behaviour is not responsible for the constant form. Short term flow behaviour is summarised in a conceptual model which proposes that the two components of long term flow are linked through base level control of the channelised flows at the intersection points between these and surface flows. Short term behaviour arises from dynamic exchanges of channel dominance through threshold controlled adjustments to intersection point base levels and non-instantaneous transmission of these base level changes up delivery channels. It is further complicated by chance interactions between fan surface topography and shifting channels causing extensive reorganisations of the channel system. It is recommended that more quantitative description of short term flow on rapidly forming fans should be limited to those subject to variable flow and in which deposition near the intersection point is less predominant.