716 results for Massey University, Doctoral
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The courage to speak : how investigative journalists persuade reluctant whistleblowers to tell their stories : a thesis submitted to Massey University in fulfillment of the requirements for the degree of Doctor of Philosophy (PhD), 2010.
Hollings, James (2010)
Doctoral thesis
Massey UniversityInvestigative journalism is often said to be based on two pillars of information gathering – documents and human sources. Yet while document retrieval and analysis have received much attention in recent years, particularly with the advent of computer‐assisted reporting and Freedom of Information legislation, remarkably little attention has been given in the journalistic literature to best practice for developing and maintaining sources, especially reluctant, vulnerable sources with high‐risk information. This thesis uses a case study approach to analyse four highprofile examples of New Zealand investigative journalism based on revelation by vulnerable and reluctant human sources. Using interviews with both the sources and the journalists who persuaded them to speak out, it draws on persuasion and social psychology theory to explain the decision‐making process of the whistleblowers and establish a model of best practice for journalists wishing to persuade reluctant, vulnerable people to speak out safely and effectively.
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Development of a computer based decision support system for introducing no-till technology : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Agricultural Engineering, Massey University, Palmerston North
Abbas, Syed Ghazanfar (1998)
Doctoral thesis
Massey UniversityNo-Till cropping systems have evolved rapidly since the early 1960s and have attracted attention world-wide. The difficulty of transferring new technologies is also well established. The selection of a tillage system is a difficult management decision with long term implications. Specific constraints impede its implementation. No-Till has the potential to conserve soil and energy as well as to sustain the agricultural ecosystem, yet some soil types have high cultivation requirements to maintain optimum soil structure. Climatic factors, such as level of precipitation, can influence both plant response to soil compaction and the timing of crop establishment. Furthermore, biological constraints such as plant diseases or specific weed species can become controlling factors governing the successful adoption of No-Till. The use of an expert system is considered the best way to derive the researchers' knowledge and aid the process of choosing an appropriate tillage technique. The No-Till Expert (NOTE) System is designed to aid farmers and extension workers in their decision-making process for promoting No-Till. A prototype expert system has been developed and initially run in Pakistan under the rice-wheat and cotton-wheat rotation. A model for popularizing No-Till technology is also proposed. Over-drilling pasture, and crop establishment data from New Zealand conditions has been incorporated for possible use of this expert system in developed agriculture. The following technical, social, and economic input parameters have been incorporated in the NOTE. Users are required to input information concerning each parameters (guidance in selecting values is provided). Technical: Soil texture, soil slope, crop rotation, weed and pest management, straw residue management, seeding technology, and soil moisture condition around seed micro-environment at the time of planting. Social: The ability to carry out a particular operation correctly determines the farmer's ability to manage No-Till successfully. Therefore, the literacy level, use of knowledge for correct and timely operations is also considered under the social aspects in this study. Economic: If the cost of productions, and productivity is not likely to vary positively with the change in tillage technique, it would be difficult for extension workers to convince farmers to change their existing practices. Thus, the economic aspects of No-Till were also considered. Environmental, local legislation, residue handling, use of chemicals, and its impact on ground water contamination were the other key factors that were considered while designing NOTE. However, these were not incorporated in the final design of NOTE because of lack of the available quantitative data. NOTE interactively considers the above parameters and makes appropriate recommendations as to the acceptance/rejection of No-Till. Based on the wide range of studies on above subjects. NOTE out-rightly rejects No-Till under the following conditions: 1. If the area is affected by rice stem borer, and the requisite pesticides are not available under Pakistani condition. 2. If the soil texture is heavy and not well drained. 3. If the requisite weed control chemicals are not available. 4. For growing cereal after pasture, as sowing of an intermediate crop is recommended under New Zealand situation because of likely transfer of Argentine stem weevil. However, if farmer could afford to apply some appropriate pesticides, No-Till could be considered. 5. If farmer does not have access to a No-Till drill. NOTE, however, has in-built facilities for future upgrading. Such upgrading would be required to account for more specific climatic conditions, locations, and crops. A User's Guide has also been developed to assist end-users to use this decision support package.
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The effect of condensed tannins upon protein degradation in the rumen and on animal production in sheep fed fresh Lotus corniculatus : a thesis in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Institute of Food, Nutrition and Human Health, College of Sciences at Massey University
Min, Byeng-Ryel (1999)
Doctoral thesis
Massey UniversityA series of in vitro, in sacco and in vivo indoor and grazing experiments were conducted at Massey University and AgResearch Grasslands, Palmerston North, New Zealand to study the effect of condensed tannins (CT) in Lotus corniculatus (Birdfoot trefoil; CV. Grasslands Goldie) upon protein digestion in the rumen and on animal production. Aspects studied included effects of CT upon proteolytic bacterial activity, protein solubilization and degradation in the rumen and wool production and reproduction in grazing sheep. The studies also investigated the potential of L. corniculatus compared with perennial ryegrass/white clover pasture (hence referred as to pasture). The nutritional effects of CT in L. corniculatus were assessed by administrating polyethylene glycol (PEG; MW 3500) into the rumen of one group of sheep (PEG sheep; CT-inactivated), whilst a separate group of sheep received water (control sheep; CT-acting). PEG selectively binds with CT, preventing the CT from binding plant proteins in the rumen, so that effects of CT can be determined by comparing CT-acting sheep with PEG sheep. The productivity of mixed age ewes in grazing trials was measured in two experiments in the summer of 1995/1996 (Chapter 2) and the summer/autumn of 1997 (Chapter 3), to evaluate the effects of CT in L. corniculatus upon efficiency of animal production. A rotational grazing system with restricted feed allowance was used in both experiments. 1. During 1995/1996 (Chapter 2), a grazing trial was conducted to evaluate the effect of CT in L. corniculatus on wool growth and on wool processing characteristics in sheep fed close to maintenance for 125 days during summer and autumn (20 December 1995 until 25 April 1996). Half the ewes received twice daily supplements of PEG. The Lotus corniculatus contained 32 g total nitrogen (N) and 28 g total CT/kg dry matter (DM) and had an in vitro organic matter digestibility of 0.70. Action of CT reduced rumen ammonia concentration (P < 0.05) and reduced blood plasma urea concentration (P < 0.01) but increased blood plasma cysteine concentration (P < 0.05) compared to their counterparts receiving PEG supplementation. The concentration of blood plasma methionine was unaffected by CT. The CT had no effect on voluntary feed intake (VFI) and average liveweight gain (P > 0.05) but increased both clean fleece weight (P < 0.05) and staple length (P < 0.001). The CT also reduced dag percentage (P < 0.05) and tended to reduce wool yellowness (P = 0.07) relative to sheep receiving PEG. There were no significant effects of CT on fiber diameter (µm), staple breaking force (Newtons), bulk density (cm3/g) or wool resilience (cm3/g). It was concluded that the action of CT in sheep fed L. corniculatus increased the efficiency of wool production, with more wool being produced at the same feed intake. 2. Another grazing trial (Chapter 3) was conducted to study the effects of CT in L. corniculatus upon VFI, concentration of plasma metabolites, reproductive efficiency and wool production in ewes during two synchronised oestrous cycles in autumn 1997. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad-libitum for the last five days before ovulation. The experiment was of 2 x 2 factorial design, using two types of forage (L. corniculatus vs. pasture), with half the ewes grazing each forage being given twice daily oral PEG supplementation. A rotational grazing system with 200 mixed aged dry ewes (52±0.88 kg/ewe) was used. The Lotus corniculatus contained 17 g total CT/kg DM in the diet selected, with only trace amounts of total CT present in pasture. Ewes grazing L. corniculatus had higher plasma concentrations of branched chain amino acids (BCAA; 57 %) and essential amino acids (EAA; 52 %) than sheep grazing pasture. Again CT in L. corniculatus had no effect on mean VFI. The PEG supplementation had no effect upon ovulation rate (OR; 1.33 vs. 1.35) and lambing percentage (1.36 vs. 1.36 %) of the ewes grazing pasture. The CT increased both OR (1.78 vs. 1.56) and lambing percentage (1.70 vs. 1.42%) in the ewes grazing L. corniculatus relative to sheep supplemented with PEG. Increases in OR and lambing % of ewes grazing L. corniculatus were due to increases in fecundity (more multiple ovulations and less single ovulations), with no effect on ewes cycling/ewes mated. Compared to ewes grazing pasture, ewes grazing L. corniculatus had increased clean fleece weight (19 %). It was concluded that action of CT in the lotus diet was partly responsible for the increased efficiency of reproduction, with more lambs being produced at the same VFI. 3. In situ and in vitro rumen incubations (Chapter 4) were used to determine the effect of CT on both the solubilization and degradation of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39; fraction 1 leaf protein) from white clover (Trifolium repens; 0.3 g CT/kg DM) and Lotus corniculatus (22.1 g CT/kg DM). The sheep used for the experiments were fed either white clover or L. corniculatus. The loss of DM and neutral detergent fibre (NDF), total N and Rubisco from polyester bags suspended in the rumen of sheep was used as a measurement of solubilisation. The effect of CT extracted from L. corniculatus on the degradation of Rubisco from white clover was measured by in vitro incubations with rumen fluid obtained from the same fistulated sheep fed either white clover or L. corniculatus. In the absence of PEG, the solubilisation of Rubisco from L. corniculatus was less rapid than the solubilisation of this protein from white clover when each forage was incubated in the rumen of sheep fed the same diet. Addition of PEG tended to increase the solubilisation of Rubisco from L. corniculatus, suggesting that CT slowed the rates of solubilization of Rubisco from this forage. The action of CT did not inhibit the in situ loss of NDF from either white clover or L. corniculatus. In the absence of PEG, the in vitro degradation of Rubisco from L. corniculatus was slower when compared to the degradation of this protein from white clover; PEG addition increased the degradation of Rubisco from L. corniculatus, but not from white clover, showing that CT was the causal agent. The addition of CT extracted from L. corniculatus markedly depressed the degradation of Rubisco from white clover, with the effect being completely reversible by PEG. The large subunit (LSU) of Rubisco was consistently degraded at a faster rate than the small subunit (SSU) and added CT had a greater effect in slowing the degradation of the LSU compared to the SSU. It was concluded that the action of CT from L. corniculatus reduces the digestion of protein in the rumen of sheep through a minor effect on solubilization and a major effect on degradation. The main effects of CT on protein solubilization and degradation seemed to be produced locally by CT present in plant tissue. 4. Eleven strains of proteolytic rumen bacteria (Chapter 5) were used to determine the effect of CT extracted from Lotus corniculatus on the in vitro proteolysis of Rubisco protein, bacterial specific growth rate and maximum optical density (ODmax). Effects of CT on the rate of Rubisco proteolysis (%/h) were determined through making measurements in the presence and absence of PEG. Streptococcus bovis strain NCFB 2476 and B315, Butyrivibrio fibrisolvens strain WV1 and C211a, Prevotella ruminicola strain 23 and C21a, Clostridium proteoclasticum B316T, Ruminococcus albus 8, Fibrobacter succinogenes S-85, Eubacterium sp. strain C12b and C124b were tested against 1.5 mg CT/ml for Rubisco proteolysis and were examined with 0, 50, 100, 200, 400, and 600 µg CT/ml for bacterial growth measurements. In general, the presence of CT markedly depressed the degradation of both the LSU and SSU of Rubisco, with the effect being completely reversible by PEG. However, the rates of proteolysis per hour for both sub-units of Rubisco varied considerably between individual bacterial species and subunits of Rubisco. In the absence of CT, S. bovis strain NCFB 2476 and B315 and P. ruminicola like-strain C21a appeared to be most active in both LSU and SSU degradation, while P. ruminicola 23, Eubacterium sp. strain C12b and C124b, C. proteoclasticum B316T, B. fibrisolvens strain WV1 and C211a had moderate to lower rates of LSU and SSU degradation. In the presence of CT, S. bovis strain NCFB 2476 and B315 and P. ruminicola-like strain C21a appeared to be most active in both LSU and SSU breakdown. Most bacterial strains showed significantly (P< 0.05-0.01) decreased specific growth rate and ODmax with increasing CT concentrations. However, some of the strains, C. proteoclasticum B316T and R. albus 8 showed transient increases in specific growth rate at low concentrations of CT (between 50 to 100 µg CT/ml), but not at high concentrations of CT. In terms of specific growth rate, addition of CT at low concentrations (50-200 µg CT/ml), S. bovis NCFB 2476, Eubacterium sp. C124b and F. succinogenes S-85 were most affected compared to the minus CT controls, while P. ruminicola sp. C21a and C. proteoclasticum B316T were not greatly inhibited at the highest concentrations of CT. The degree of inhibition of both bacterial growth and Rubisco degradation in the presence of CT varied considerably between individual bacterial species and will be discussed in Chapter 5. It was concluded that action of CT from L. corniculatus reduces both the rate of Rubisco proteolysis and the growth rate of proteolytic rumen bacteria, but the magnitude of the CT effect differed between strains used. 5. Twelve six month old Romney sheep were fistulated in the rumen and abomasum and fed Lotus corniculatus (32 g CT/kg DM), to examine the effects of CT on proteolytic rumen bacterial populations and on quantitative N digestion in the rumen. Half the animals were given continuous intraruminal infusions of PEG. In the first part of the experiment, the populations of four proteolytic rumen bacteria were enumerated directly from rumen samples using a competitive polymerase chain reaction (cPCR) technique. During pre-feeding on a perennial ryegrass/white clover pasture diet, populations of C. proteoclasticum B316, Eubacterium sp. C12b, S. bovis B315 and B. fibrisolvens C211a were 1.6 x 10 8, 2.7 x 10 8, 7.1 x 10 6 and 1.2 x 10 6 per ml respectively. When the diet was changed from pasture to L. corniculatus (average of 8 h to 120 h), the average populations of C. proteoclasticum B316, Eubacterium sp. C12b, S. bovis B315 and B. fibrisolvens C211a from the same animals were decreased significantly (P < 0.001) to 5.1 x 10 7, 1.5 x 10 8, 2.6 x 10 6 and 1.0 x 10 6 per ml, respectively. When the PEG was infused into the rumen of sheep fed L. corniculatus, the populations of proteolytic bacteria were significantly increased (P < 0.01-0.001) compared to the CT-acting group. Rumen proteinase activity, concentrations of rumen ammonia and soluble N were decreased significantly (P < 0.05-0.001) in the CT-acting compared to the PEG treatment group. In the quantitative N studies, the principal effects of CT were to reduce rumen N digestibility (P < 0.05) and ammonia pool size, and to increase the flow of non-ammonia nitrogen (NAN) to the abomasum. Dry matter intake and DM digestibility were unaffected. The N intake, rumen NAN and microbial NAN pool sizes were similar in both CT-acting and PEG sheep. Non-microbial NAN fluxes to the abomasum were significantly higher (P < 0.01) in the CT-acting sheep than in the PEG sheep, but microbial NAN flux to the abomasum was unaffected by treatment. It was concluded that L. corniculatus CT reduced forage protein degradation in the rumen, and increased the flow of undegraded feed NAN to the abomasum. Proteolytic bacterial populations seemed to be reduced by CT, but these changes did not effect the total rumen microbial NAN pool or abomasal microbial NAN flux. Therefore, more protein was potentially available for absorption from the small intestine. 6. This study is the first to report that action of CT increased reproductive efficiency in grazing ewes. It is also the first study to show that action of CT decreased proteolytic bacterial populations measured directly from rumen samples using cPCR techniques. Feeding forages containing CT such as L. corniculatus has been shown to reduce proteolysis in the rumen, with the mechanisms being to slightly reduce protein solubilization, to markedly reduce protein degradation and to reduce the populations of proteolytic bacteria. CT increased NAN flux into the abomasum (in indoor studies) and increased animal production in grazing ewes without affecting VFI, thus improving the efficiency of animal production. It is concluded that forage CT can be used to increase the efficiency and sustainability of livestock production from grazed forages.
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The virtualMe : a knowledge acquisition framework : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (Ph.D.) in Information Systems at Massey University, Palmerston North, New Zealand
Verhaart, Michael Henry (2008)
Doctoral thesis
Massey UniversityThroughout life, we continuously accumulate data, information and knowledge. The ability to recall much of this accumulated knowledge commonly deteriorates with time, though some forms part of what is referred to as tacit knowledge. In the context of education, students access and interact with a teacher’s knowledge in order to create their own, and may have their own data, information and knowledge that could be added to teacher’s knowledge for everyone’s benefit. The realization that students can contribute to enhancing personal knowledge is an important cornerstone in developing a mentor (teacher, tutor and facilitator) focused knowledge system. The research presented in this thesis discusses an integrated framework that manages an individual’s personal data, information and knowledge and enables it to be enhanced by others, in the context of a blended teaching and learning environment. Existing related models, structures, systems and current practices are discussed. The core outcomes of this thesis include: • the virtualMe framework that can be utilized when developing Web based teaching and learning systems; • the sniplet content model that can be used as the basis for sharing information and knowledge; • an annotation framework used to manage knowledge acquisition; and • a multimedia object (MMO) model that: o allows for related media artefacts to be intuitively grouped in a logical collection; o includes a meta-data schema that encompasses other metadata structures, and manages context and referencing; and o includes a model allowing component parts to be reaggregated if they are separated. The virtualMe framework provides the ability to retain context while transferring the content from one person to another and from one place to another. The framework retains the content’s original context and then allows the receiver to customise the content and metadata so that the content becomes that person’s knowledge. A mechanism has been created for such contextual transfer of content (context retained by the metadata).
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Understanding driving-related fear : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University
Taylor, Joanne Elizabeth (2002)
Doctoral thesis
Massey UniversityDriving-related fear (DRF) has been investigated predominantly through research on the psychological consequences of motor vehicle accidents. There is a small but growing literature documenting the characteristics of DRF within a broader population. These few studies have described DRF as diagnostically complex and difficult to characterise in terms of clear anxiety disorders. Particularly problematic is the frequent presence of many different foci of fear and fear cognitions that are typically used to distinguish the various anxiety disorders. In addition, driving skills in those who report DRF has been a neglected issue in previous studies. The central aim of the present study was to conduct a comprehensive examination of the clinical characteristics of those who report DRF. Such an investigation would help to generate a clearer understanding of the nature of DRF and subsequently inform approaches to assessment and treatment. The present research comprised two separate studies. Study One aimed to ascertain the need for more comprehensive research by comparing the characteristics of drivers who were fearful as a result of a motor vehicle accident (MVA) with those who developed their DRF through other means. Participants were 85 media-recruited volunteers who reported some degree of DRF. Questionnaire data provided information on the types of concerns and expectations while driving, as well as various measures of anxiety and fear severity. There were few prominent differences between those who attributed their DRF to an MVA and those who reported some other reason for their fear. In addition, the data suggested useful preliminary subtypes of DRF that would benefit from further research attention. Study One then provided the impetus for Study Two, which entailed a more comprehensive investigation of the clinical characteristics and subtypes of DRF, as well as an examination of the role of driving skills in DRF. Study Two involved a quasi-experimental approach to the analysis of data from media-recruited driving-fearful and control groups each comprised of 50 participants. The control group was matched by average age and years of driving experience. All participants completed an initial questionnaire that provided demographic data as well as information about driving history and DRF. Various self-report measures of anxiety, fear, and avoidance behaviour were included in the initial questionnaire. Subsequently, those participants who met selection criteria underwent a diagnostic interview, further self-report questionnaires, and a practical driving assessment. Measures of self-rated and instructor-rated participant anxiety and driving skill were completed in conjunction with the driving assessment, mainly to ascertain the potential impact of test anxiety on the assessment results. Fearfuls were characterised by the reported severity of DRF when compared with controls. Helpseeking behaviour was not reflected in the relatively high levels of fear, anxiety, and avoidance behaviour reported by the fearful group. This was of particular concern given that almost half of the fearfuls met diagnostic criteria for at least one anxiety disorder. Social concerns (i.e., the perceptions of others) as a focus of fear were evident throughout the assessment, and fearfuls rated a higher likelihood of being involved in an MVA than controls, as well as higher levels of concern about the negative reactions of other drivers and injuring other people while driving. Subtypes of DRF were identified and will be an important focus for future research. In what is thought to be the first investigation of driving skills in DRF, the practical driving assessment found that fearfuls made more errors than controls. However, the pattern of errors was identical for both groups, indicating that fear and anxiety may affect the number rather than the type of errors made. The relationship between DRF and driving skills was discussed and then placed within the context of broader theories of driver behaviour. While the present research has served to further the understanding of DRFs and, in particular, has provided a starting point for understanding the role of driving skills in such fears, many avenues for future research are suggested. Additional studies will help to further clarify the findings of the present research, and to develop more clearly the kinds of practical and clinical recommendations that form the basis of efficient and effective treatment for DRF.
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Evolutionary analyses of large data sets : trees and beyond : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University
Holland, Barbara Ruth (2001)
Doctoral thesis
Massey UniversityThe increasing amount of molecular data available for phylogenetic studies means that larger, often intra-species, data sets are being analysed. Treating such data sets with methods designed for small interspecies data may not be useful. This thesis comprises four projects within the field of phylogenetics that focus on cases where the application of current tree estimation methods is not sufficient to answer the biological questions of interest. A simulation study contrasts the accuracy of several tree estimation methods for a particular class of five-taxon, equal-rate, trees. This study highlights several difficulties with tree estimation, including the fact that some tree topologies produce “misleading" patterns that are incorrectly interpreted; that correction for multiple changes does not always increase accuracy, because of increased variance; and the difficulty of correctly placing outgroup taxa. A mitochondrial DNA data set, containing over 400 modern and ancient Adélie penguin samples, is used to estimate the rate of evolution. Straightforward tree-estimation is unhelpful because the amount of homoplasy in the data makes the construction of a single reliable tree impossible. Instead the data is represented by a network. A method, that extends statistical geometry, assesses whether or not a data set can be well-represented by a tree. The "tree-likeness" of each quartet in the data is evaluated and displayed visually, either for the entire data set or by taxon. This aids in identifying reticulate (or simply noisy) data sets, and also particular taxa that confound tree-like signal. Novel methods are developed that use pairwise dissimilarities between isolates in intra-species microbial data sets, to identify strains that are good representatives of their species or subspecies.
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What is this thing called grandparenting? : the social, economic and political influences on the role in New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Social Work and Social Policy, School of Health and Social Sciences, Massey University, Palmerston North, New Zealand
Read, Lesley Florence Collington (2010)
Doctoral thesis
Massey UniversityIn 2003 Statistics New Zealand was describing grandparenting as an ‘emerging field’. There exists very little academic material on the subject in New Zealand although there is a prolific literature from the US and increasing interest from Britain and other countries in the West. This research study sets out to explore the nature of grandparenting in New Zealand, past and present, reviewing the social, economic and political influences on the role as it is today. From a review of the international literature three distinct models of grandparenting were identified for enquiry. They are: • The full-time care grandparent with parental responsibilities. • The grandparent providing regular supplementary care to assist parent/s to fulfil the parenting needs of their children (e.g. when parents are in work). • The grandparent with a role characterized as voluntary and varied, outside parent type responsibilities. Choosing an interpretive approach, I used a case study method of research. Eighteen grandparents were interviewed, some from each model. Additionally six grandparents, two from each model, kept a diary of their grandparenting activity over three months. Grandparents were purposefully selected to represent wide variability. From grandparents in all three grandparenting models there is evidence of a strong emotional commitment to adult children’s families. From past relationship with grandparents, or less often from observing their parents grandparenting their children, the grandparents have learnt a model of grandparenting which is carried into the present. There it is typically expressed in a variety of nurturing and protective behaviours. In this manner grandparents have the potential to provide continuity, stability and a sense of belonging at the micro-social level of the family, and in doing so, at the macro-level, to the broader fabric of society. When, from social and/or economic circumstance grandparents are parenting grandchildren, they are likely to suffer a deteriorating quality of life, with health and finances especially affected. Grandparents who are providing regular, supplementary care of grandchildren also sometimes experience these effects. Social policies sensitive to both the micro- and macrosocial value of grandparents are needed to address their vulnerabilities.
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Fruit & vegetable intake amongst men in New Zealand : an evaluation and extension of a stage and continuous model of dietary behaviour : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Palmerston North, New Zealand
Jury, Angela Faye (2008)
Doctoral thesis
Massey UniversityPurpose. The purpose of the study is to develop a better understanding of the process of behaviour change and factors which contribute to an increased level of fruit and vegetable intake (F&V) among men in New Zealand. The study aims to determine the impact of psychosocial and contextual factors integrated into an extended stage model. As a more parsimonious continuous model maybe sufficient for understanding F&V intake, the study also plans to evaluate the impact of psychosocial and contextual factors on behaviour, and whether intentions is the mechanism by which the psychosocial factors influence behaviour. Design. Data was collected using a self administered questionnaire in a mail survey from N = 518 men aged 18 years and over randomly selected from the electoral roll. Mean differences in factors across the stages of change were assessed with one way ANOVAs and Games Howell post hoc tests, and trend analyses assessed linear and non-linear components of trend. The independent impact of factors on intentions and behaviour was assessed with hierarchical multiple regression analyses. Measures. Stage of change was assessed with a single item measure, F&V intake with a 7-item food frequency questionnaire, and food insecurity with items used in the 1997 National Nutrition Survey. Previously developed measures were used to assess the pros, cons, self efficacy, self identity, and susceptibility to disease. Scales were developed and adapted for F&V intake for control, descriptive and subjective norms. Results. In total, 51% of men were in the action/maintenance stage and 32%, 10% and 7% in the precontemplation, contemplation, and preparation stages respectively. Mean F&V intake was 3.92 (SD = 2.08) servings a day and 30.4% were eating at least 5 servings. All factors differed significantly across the stages of change. The predictor variables collectively explained R² = 43% (42% adjusted) in intentions and 40% (38% adjusted) in behaviour. The impact of self efficacy and intentions on behaviour depended in part on household food insecurity status. Discussion. Similar conclusions were reached using the stage and continuous model. To increase intentions of eating 5 or more servings of F&Vs a day in the future, interventions should modify perceived norms, self efficacy, pros and cons, and awareness of F&V guidelines. Interventions targeting those with high food insecurity may also be required to help translate their intentions into action.
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The humanitarian and the soldier: partners for peace? A study of US and New Zealand military-NGO relations : a thesis presented in fulfilment of the requirement for the degree of Doctor of Philosophy in Defence Studies at Massey University, Manawatu, Palmerston North, New Zealand
Jacobs-Garrod, Laura M. (2010)
Doctoral thesis
Massey UniversityOver the past two decades, military forces and aid workers have found themselves co-existing time and time again on unconventional battlefields. While efforts have been made to coordinate their respective missions, the relationship between the military and non-governmental organisations (NGOs) remains ad hoc. This improvisational approach to military-NGO relations yields uneven and, often, inefficient results in responses to complex emergencies. To gain a better understanding of the military-NGO relationship and its implications for international interventions, this study identifies the strengths and weaknesses, comparative advantages, and gaps in capabilities of the military-NGO relationship using the New Zealand Defence Force (NZDF) and United States Military experiences. This study addresses three key questions. These are: Does a lack of cooperation in military-NGO relations exist and, if it does, how does it inhibit the efficacious response to complex emergencies? What impact do the structures and philosophies of both military and humanitarian organisations have on the military-NGO relationship? Using the strategic, operational and tactical levels to evaluate the case studies, what has, and has not, worked within the military-NGO relationship and how can those successes and failures contribute to building a model for the military-NGO relationship? While not a key question, there is a fourth area which this study briefly addresses in order to compare and contrast the military-NGO relationship of two different countries: Does the US military or the New Zealand Defence Force have a comparative advantage in the military-NGO relationship? Many lessons are drawn from military-NGO experiences in the four case studies of this research: Somalia, Bosnia, East Timor, and Afghanistan. The military-NGO relationship was a hot button issue in 1991 to 1993 after operations in Northern Iraq and Somalia, and it has re-emerged as a critical issue today as the international community continues to engage in complex emergencies in countries such as Iraq and Afghanistan. As Operation Enduring Freedom in Afghanistan enters its ninth year, militaries and aid agencies are continuing to debate their interplay in many of the same terms they did in 1993. This study examines the collective experiences- both positive and negative- of military-NGO relations and seeks practical strategies for a cooperative relationship.
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Gut endogenous protein flows and postprandial metabolic utilization of dietary amino acids in simple-stomached animals and humans : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Human Nutrition at Massey University, Palmerston North, New Zealand
Deglaire, Amelie (2008)
Doctoral thesis
Massey UniversityDietary protein quality depends on two key measures: true ileal protein digestibility and the metabolic utilization of absorbed amino acids (AA). The objectives of this study were to determine the influence of two dietary factors (antinutritional factors and peptides) on ileal endogenous protein flows; to validate the intubation technique used in humans for ileal digesta sampling; to determine the postprandial metabolic utilization of dietary AA depending on their delivery form and to assess the validity of the growing pig for predicting true ileal protein digestibility in the adult human. Investigations were undertaken in the growing rat, growing pig and adult human. Ileal digesta were collected from euthanised rats, post valve T-caecum cannulated pigs, and naso-ileal intubated conscious adult humans. Ileal endogenous nitrogen (N) and AA were measured using a protein-free (PF) diet, diets containing 15N-labelled casein in the intact (C) or hydrolysed (HC) form, or a diet based on free AA (diet A), for which some dispensable AA were omitted to allow a direct determination of their endogenous flows. Digesta centrifugation and ultrafiltration (diet HC) allowed for the determination of ileal endogenous protein flows and the extent of tracer (15N) recycling. Antinutritional factors from a crude extract of kidney beans (Phaseolus vulgaris), when given at amounts commonly ingested in practice, enhanced ileal endogenous protein flows (rats, PF diet). After adaptation to the diet, body N balance per se did not influence ileal endogenous protein flows (rats, diets PF and A) but dietary peptides led to greater ileal endogenous AA and N flows compared with a protein-free diet. Dietary peptides (HC), compared with peptides naturally released in the gut during protein digestion (C), did not enhance ileal endogenous protein flows (rats, pigs, and humans). The extent of tracer recycling, however, was maximal in frequently-fed rats, lower in meal-fed pigs and minimal in meal-fed humans (65, 21, and 11% of 15N-labelled ileal endogenous proteins, respectively). Naso-ileal intubation for ileal digesta sampling in humans was shown to be an accurate method and evidence was obtained supporting the growing pig as a valid model for predicting true ileal protein digestibility in the adult human. Finally, the form of delivery of dietary AA (from HC or C) influenced the postprandial metabolic fate of dietary AA, especially in terms of AA catabolism kinetics. However, the overall nutritional value of C and HC were similar.
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Epidemiological investigations of surveillance strategies of zoonotic Salmonella : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University
Benschop, Jacqueline (2009)
Doctoral thesis
Massey UniversityThis thesis is concerned with the application of recently developed epidemiological and statistical tools to inform the optimisation of a national surveillance strategy of considerable importance to human health. The results of a series of epidemiological investigations of surveillance strategies for zoonotic Salmonella are presented. Salmonella are one of the most common and serious zoonotic foodborne pathogenic bacteria globally. These studies were motivated by the increasing focus on the cost-effectiveness of surveillance while maintaining consumer confidence in food supply. Although data from the Danish Salmonella surveillance and control programme has been used in these investigations, the techniques may be readily applied to other surveillance data of similar quality. The first study describes the spatial epidemiological features of Danish Salmonella surveillance and control programme data from 1995 to 2004, using a novel method of spatially adaptive smoothing. The conditional probability of a farm being a case was consistently high in the the south-west of Sonderjylland on the Jutland peninsula, identifying this area for further investigation and targeted surveillance. The identification of clustering of case farms led into the next study, which closely examines one year of data, 2003, for patterns of spatial dependency. K-function analyses provided evidence for aggregation of Salmonella case farms over that of all farms at distances of up to six kilometres. Visual semivariogram analyses of random farm-level effects from a Bayesian logistic regression model (adjusted for herd size) of Salmonella seropositivity, revealed spatial dependency between pairs of farms up to a distance of four kilometres apart. The strength of the spatial dependency was positively associated with slaughter pig farm density. We describe how this might inform the surveillance programme by potentially targeting herds within a four kilometre radius of those with high levels of Salmonella infection. In the third study, farm location details, routinely recorded surveillance information, and industry survey data from 1995 were combined to build a logistic seroprevalence model. This identified wet-feeding and specific pathogen free herd health status as protective factors for Salmonella seropositivity, while purchasing feed was a risk factor. Once adjusting for these covariates, we identified pockets of unexplained risk for Salmonella seropositivity and found spatial dependency at distances of up to six km (95% CI: 2–35 km) between farms. A generalised linear spatial model was fitted to the Jutland data allowing formal estimation of the range of spatial correlation and a measure of the uncertainty about it. There was a large within-farm component to the variance, suggesting that gathering more farm level information would be advantageous if this approach was to be used to target surveillance strategy. The fourth study again considers data from the whole study period, 1995 to 2004. A detailed temporal analysis of the data revealed there was no consistent seasonal pattern and correspondingly no benefit in targeting sampling to particular times of the year. Spatiotemporal analyses suggested a local epidemic of increased seroprevalence occured in west Jutland in late 2000. Lorelogram analyses showed a defined period of statistically significant temporal dependency, suggesting that there is little value in sampling more frequently than every 10 weeks on the average farm. The final study uses findings from the preceding chapters to develop a zero-inflated binomial model which predicts which farms are most at risk of Salmonella, and then preferentially samples these high-risk farms. This type of modelling allows assessment of similarities and differences between factors that affect herd infection status (introduction) and those that affect the seroprevalence in infected herds (persistence and spread). The model suggested that many of the herds where Salmonella was not detected were infected but at a low prevalence. Using cost and sensitivity, we compared the results with those under the standard sampling scheme based on herd size, and the recently introduced risk-based approach. Model based results were less sensitive, but showed significant cost savings. Further model refinements, sampling schemes, and the methods to evaluate their performance are important areas for future work, and should continue to occur in direct consultation with Danish authorities.
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Responses of South Island Hector's dolphins (Cephalorhynchus hectori hectori) to vessel activity (including tourism operations) in Akaroa Harbour, Banks Peninsula, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Marine Biology at Massey University, Auckland, New Zealand
Martinez, Emmanuelle (2010)
Doctoral thesis
Massey UniversityFor over 25 years, tour operators have been undertaking view and swim-with-dolphin trips in Akaroa Harbour off Banks Peninsula, east coast South Island, New Zealand. Following the international exponential growth in the commercial dolphin-based tourism industry, Akaroa Harbour is now a key eco-tourism destination in New Zealand with 32 daily permitted trips targeting Hector’s dolphin (Cephalorhynchus hectori hectori). Such a high number of trips is of particular concern given that this species is not only endemic but also endangered. Our current understanding of the effects of tourism activities on Hector’s dolphins in Akaroa Harbour is far from satisfactory. To ensure the sustainability of the economically-important and rapidlygrowing dolphin-based tourism industry, there is an urgent need for sound scientific evidence on which to base management decisions. One of the challenging issues with the assessment of tourism impacts is the lack of baseline data. Prior to beginning the evaluation of the effects of disturbance on this population, data relating to the occurrence and demographics of Hector’s dolphins, as well as vessel traffic in Akaroa Harbour, were collected from land-based platforms during three consecutive austral summers (November and March), commencing in 2005. Examination of Sighting Per Unit Effort (here number of dolphin sightings per hour) and the dolphin fine-scale spatial distribution confirmed an inshore-offshore migration and, in the case of the latter, higher density patterns between the Kaik hills and the harbour entrance. However, no specific area was associated with a particular behaviour or nursery groups. The majority of groups consisted of adults only (91.2%, n = 2,000) and comprised mainly 2-5 individuals (83.2%). Group size varied with behaviour, being larger when socialising. Activity budgets within two outer bays were very comparable to Akaroa Harbour, except for socialising. In the harbour, Hector’s dolphins only spent a small proportion (14%) of their day (0600-1800 hr) in the absence of vessels. Vessel traffic in the harbour consisted mainly of recreational vessels (72.9%) although commercial vessels represented 70.4% of observed encounters and interacted twice as long with the dolphins. No displacement was evident and as a result, Hector’s dolphins might compensate for high vessel traffic levels by adjusting their behavioural budget. To determine the effects of tourism activities on Hector’s dolphins’ behavioural budget, focal-group follows using a scan sample methodology were conducted from land-based stations and analysed using Markov chain models (n = 330 sequences). Vessel presence affected the activity budget of Hector’s dolphins by changing transition probabilities, bout durations and the time taken to return to a behavioural state once disrupted. Both diving (inferred foraging) and travelling were significantly disrupted by vessel interactions. The addition of one of more vessels during an encounter further disrupted diving. Responses of Hector’s dolphins to swim attempts were assessed from commercial tourism vessel trips (n = 420). The method of approach and swimmer placement affected the dolphins’ behaviour, with a reduction in avoidance when regulations were adhered to, i.e. using line abreast and around methods. Dolphin responses to swim encounters were also correlated with the number of successive attempts, dolphin group size and initial behaviour. Although Hector’s dolphins appear to be more tolerant of the presence of swimmers over time, some level of sensitisation to seasonally high levels of vessel interactions was also detected. The effects of swim encounters could potentially be exacerbated by the use of stones as an auditory stimulant. Specifically, swimmers who used stones had a greater probability of close and sustained approaches by dolphins than those who sang or simply floated on the surface of the water. Based on opportunistic photo-identification surveys (n = 254), 46% and 44% of the 50 identifiable individuals were infrequently and occasionally recorded interacting with commercial tourism vessels, respectively. It was also estimated that individuals using Akaroa Harbour are exposed to the highest level of cetacean-based tourism in New Zealand. This implies that dolphins that are frequent users of the harbour are likely to be more exposed to intensive tourism pressure. The high resighting rate of some individuals further suggests that frequent users are unlikely to discontinue using the harbour, even though they face increased human disturbance. Data presented here reveal the nature and the susceptibility of Hector’s dolphins to tourism activities, warranting the continuation of a moratorium on new permits. Furthermore, a reduction in daily trip numbers should be considered. Ongoing monitoring of this population’s response to tourism activities, combined with an integrated and adaptive approach to management, gives the best chance of ensuring the sustainability of the industry.
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Contemporary migration between developed countries : transformation processes towards actualizing authentic selves and lives : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Manawatu, New Zealand
Bürgelt, Petra Topaz (2010)
Doctoral thesis
Massey UniversityPrevious migration research has focused on immigration, individual characteristics, and dysfunctional outcomes. Yet, what still eludes us is an understanding of what drives migration between technologically advanced high income countries and what psychoenvironmental processes influence migration from the perspective of migrants themselves. To fill these gaps, this study holistically explored the migration process from the perspective of migrants in the context of their life course experiences. I synergised the assumptions of the salutogenic paradigm, symbolic interactionism, and narrative theory, which led to the methodological merging of constructionist grounded theory and ethnography. For two years, I accompanied 17 potential or actual German migrants throughout their migration journey to Australia or New Zealand. I travelled to Germany and lived with them in their homes for up to 7 days. I observed them, participated in their lives, and listened to the experiences and interpretations they shared in multiple episodic interviews. Those who migrated, I visited in Australia or New Zealand 6 and 18 months after migrating. Those who did not migrate, I visited after two years in Germany. Throughout the study, participants reported their experiences and interpretations in email or phone diaries. I analysed the thick data using grounded theory and narrative analysis strategies. A composite migrant narrative and a summary of variations represent the development of the migration idea and what happened during emigrating and immigrating. Migration is a lifetime process that starts in childhood and is influenced by the subjective interpretations of the continuous interaction between self and the world. Actualising one‟s self and living an authentic life is the deeper driver of migration. Four processes are involved in migrating: becoming conscious of self and the world, detaching from cultural roots, gaining confidence and capabilities, and living in the gap. The motivations, characteristics, and processes identified, correspond with those of people who are at the more advanced stages of self-actualisation (Maslow, 1970) and moral development (Kohlberg, 1984), and who are cosmopolitans (e.g., Featherston, 2002; Skribis, Kendall, & Woodward, 2004; Turner, 2002). The findings substantiate, extend, and synergise the writings of migration scholars from the various disciplines. They highlight the importance of considering holistically all factors the different disciplines investigate. The findings suggest interesting synergies between the assumptions of symbolic interactionism and existentialism as epistemological frameworks.
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Expectations, emerging issues and change for Chinese international students in a New Zealand university : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Second Language Teaching at Massey University, Palmerston North, New Zealand
Skyrme, Gillian Ray (2008)
Doctoral thesis
Massey UniversityThis study uses a sociocultural framework to trace the experiences of 24 Chinese international undergraduate students studying business and information sciences in a New Zealand university, using community of practice perspectives recognising the university as a site of complex discourses requiring negotiation of new identities and practices. The students’ expectations, the issues that emerged and the processes of change they went through to meet their goals were investigated from retrospective and longitudinal viewpoints, using semi-structured interviews supported by schematic representations developed by the researcher and photographic representations compiled by participants were. The findings suggest that preparation before departure focused largely on expected English demands, rather than wider matters of academic culture, and this was only partially rectified during prior study in New Zealand. Students thus entered the university unfamiliar with its specific discourses and found conditions for resolving difficulties more limited than previously experienced. The anonymity and extreme time pressure pertaining in large first-year classes led to bewilderment about requirements, threats to the sense of identity as competent students which they had arrived with, and often, failure of courses. Nevertheless, the investment, personal and monetary, which this journey represented provided the incentive to persevere. Most students were resourceful in negotiating a fit between their learning preferences and the affordances of the university, resulting in very different journeys for each of them. Measures adopted included those sanctioned by the university, such as developing skills to meet the demands of academic literacies, and others less valued, such as extreme dependence on teacher consultation. Success was gained through personal agency which proved more important than the university goal of student autonomy. Beyond the academic arena, other activities such as part-time jobs were significant in contributing to a sense of identity as competent and educated adults, and to new viewpoints which contrasted with original cultural norms. They continued to identify as Chinese, but in a “third space” owing something to New Zealand influences. The study concludes that entry criteria should include a component of university preparation. It also recommends measures by which the university might enhance the experiences of such students.
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Flight of the kiwi : an exploration of motives and behaviours of self-initiated mobility : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Auckland, New Zealand
Thorn, Kaye Jennifer (2008)
Doctoral thesis
Massey UniversityThe primary aim of this study was to identify the motives for self-initiated mobility of highly educated New Zealanders across national boundaries. It further seeks to identify the relative importance of these motives and to explore relationships between motivation and mobility behaviour. This study on self-initiated mobility is opportune as an increasingly globalised market place and a demand for the skills of the highly educated result in competition for workers. Most literature concerning mobility focuses on expatriate assignment. By comparison, self-initiated movers remain an under-researched group. Moreover, of the limited research on self-initiated mobility, most have used interviewing and narrative methods, so that the available information is detailed but restricted to individual experiences. This study used a self-report survey via the internet to collect both quantitative and qualitative data and yielded 2,608 useable responses from New Zalanders living and working throughout the world. It was highly exploratory, using the analytical marketing tool CHAID to show linkages between subjective attitudinal motives and objective measures of moility behaviours. The desire for cultural and travel opportunities was the dominant subjective motive, being the best predictor for the objective mobility behaviours of establishment, current spatiality and return propensity and being a secondary predictor for restlessness. Other associations were evident between the quality of life motive and the behaviour of restlessness, the career motive and cultural globalism and the relationships motive and the behaviour of latent transience. Economics and the political environment motives were not found to be significant predictors of any behaviour. The subjective data reinforced the importance of the cultural and travel opportunities and career motives, ranking these the most important motives in a decision to be mobile. Within these motives, opportunities for travel and adventure and for career development were central. Economics was ranked as the third most important motive, contrary to extant literature, followed by relationships, quality of life and the political environment. The priority accorded to each of these six motives varies according to gender, location and life stage, creating different equations of motivation.
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Risk-based suveillance in animal health : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand
Prattley, Deborah Jayne (2009)
Doctoral thesis
Massey UniversityAnimal health surveillance is an important part of animal health care, particularly in countries dependent on livestock for food production and international trade. There are two major issues related to the provision of e®ective surveillance activities. Firstly, for good information to become available, the design and conduct of data collection activ- ities should be carried out following sound statistical principles. In reality, constraints such as imperfect tests and unavoidably-biased sampling strategies hinder straightfor- ward analysis and interpretation of survey results. Risk-based surveillance is used to target high-risk sub-populations to increase e±ciency of disease detection; however, biased datasets are generated. This thesis develops methodologies to design risk-based surveillance systems and al- low statistically valid analysis of the inherently biased data they generate. The ¯rst example describes the development of a method to analyse surveillance data gathered for bovine spongiform encephalopathy (BSE). The data are collected from four dif- ferent surveillance streams of animals tested for BSE, with each stream containing unavoidable biases and limitations. In the BSurvE model, these data are combined with demographic information for each birth cohort to estimate the proportion of each birth cohort infected with BSE. The prevalence of BSE in a national herd can then be estimated using the method of moments, whereby the observed number of infected animals is equated with the expected number. The upper 95% con¯dence limit for the prevalence is estimated both for infected countries and for those where no BSE has previously been detected. A similar approach to that used in BSurvE is then applied to surveillance data for trichinellosis, for which risk-based post-mortem testing is also performed. Negative results from multiple species using di®erent, imperfect tests are combined to give an estimate of the upper 95% con¯dence limit of the national prevalence of trichinellosis in a reference population. This method is used to provide support for freedom from trichinellosis in Great Britain. A di®erent approach to risk-based surveillance is explored as the surveillance strategy for detection of exotic causes of abortion in sheep and goats in New Zealand is examined. Using a geographic information system (GIS) maps of disease risk factors were overlain to produce a risk landscape for the lower North Island. This was used to demonstrate how areas of high- and low-risk of disease occurrence can be identi¯ed and used to guide the design of a risk-based surveillance programme. Secondly, within one surveillance objective there may be many ways in which the available funds or human resources could be distributed. This thesis develops a method to assess BSE surveillance programmes, and provides tools to facilitate BSE detection on the basis of infection risk and to increase the e±ciency of surveillance strategies. A novel approach to allocation of resources is developed, where portfolio theory con- cepts from ¯nance are applied to animal health surveillance. The example of surveil- lance for exotic causes of sheep and goat abortion is expanded upon. Risk of disease occurrence is assessed for a population over di®erent time periods and geographical areas within a country, and portfolio theory used to allocate the number of tests to be carried out within each of these boundaries. This method is shown to be more likely to detect disease in a population when compared to proportional allocation of the available resources. The studies presented here show new approaches that allow better utilisation of imperfect data and more e±cient use of available resources. They allow development of surveillance programmes containing an appropriate balance of scanning and targeted surveillance activities. Application of these methods will enhance the implementation and value of surveillance in animal health.
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Modelling infectious disease epidemiology and vaccination impact : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University, Albany, New Zealand
Mann, Joanne L. (2009)
Doctoral thesis
Massey UniversityThis thesis presents mathematical models for the dynamics of vaccine preventable diseases, specifically looking at the New Zealand situation. Through the use of integral and differential equations, we develop models and compare the results of these to known data. Using game theory analysis we determine and compare the proportion of the population that needs to be vaccinated in order to minimise the expected costs to the individuals in the population and to the community. Two different scenarios and methods are considered, where the effects of vaccination last only one epidemic cycle (using an integral equation method) and where vaccination is effective over an entire lifetime (using a differential equation method). For both scenarios, we find that the minimum cost for the individuals is reached when a lower proportion of the population is vaccinated than needed for the minimum cost to the community. We then elaborate on the integral equation method to produce a model for repeated epidemics of measles in a population, where a discrete mapping is used to include the year to year demographics of the population. The results of this model show a different epidemic pattern then that produced from a differential equation model, with numerical problems encountered. From here on, we use differential equation models in our analysis. A critique and extension to an existing model for the dynamics of the hepatitis B virus is presented, with discussion on the appropriateness of the model’s construct for predicting the incidence of infection. Alternative differential equation models for hepatitis B virus and immunisation that include splitting the population into age groups with nonhomogeneous mixing are presented. The results of these models are compared with the known data on incidence of infection and carriage in New Zealand, showing how affective different immunisation schedules may have been. Differential equation models are then presented for meningococcal B virus epidemiology in New Zealand, with the models incorporating different features of the virus until the best model is found that fits the New Zealand data. Each model is compared with the known incidence of infection, with the population being either treated as a whole or split into age groups with non-homogeneous mixing. The effect of vaccination is included in this model so that we can explore the future of the infection in the population, and how best to tackle any future epidemics. The model shows that the current vaccination campaign was the best solution for controlling the epidemic, but there will be epidemics in the future that will need subsequent vaccination campaigns to limit the number of infections.
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Expression of ACC oxidase genes in white clover (Trifolium repens L.) roots in response to phosphate supply : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Molecular Biology at Massey University, Palmerston North, New Zealand
Roldan, Marissa B. (2008)
Doctoral thesis
Massey UniversityThe differential expression of members of the Trifolium repens ACC oxidase (TR-ACO) gene family and accumulation of TR-ACO proteins in white clover roots, and the temporal TR-ACO gene expression and TR-ACO protein accumulation in response to phosphate (Pi) stress has been investigated. Four-node stolon cuttings of wild type and transgenic white clover (designated TR-ACOp::GUS and TR-ACO1p::mGFP5-ER) plants were rooted and acclimatised in Hoagland’s solution, and then subjected to either a Pi sufficiency (1 mM Pi) treatment or a Pi depletion (10 µM Pi) treatment over a designated time course. Using semi quantitative Reverse Transcriptase-Polymerase Chain Reaction (sqRT-PCR) and gene-specific primers it has been determined that the TR-ACO genes are differentially expressed in the roots of white clover. The TR-ACO1 transcript abundance was greater in the lateral roots when compared to the main roots. By immunodetection analysis using antibodies raised against TR-ACO1, recognition of a protein of expected size (ca. 36 kDa) was also greater in the lateral roots. The tissue-specific localisation of TR-ACO1 promoter activity was investigated first by light microscopy using a single genetic line of white clover transformed with a TR-ACO1p::GUS gene construct, and results then confirmed by confocal microscopy using several genetically independent lines of transgenic plants transformed with a TR-ACO1p::mGFP5 ER gene construct. In these lines, the TR-ACO1 promoter activity was primarily located in the meristem of the main and lateral roots, lateral root primordia as well as in the pericycle of the root with nodes of expression in the emerging lateral roots, suggesting a role for ethylene in the development of young tissues where cells are actively dividing. In terms of TR-ACO2, greater transcript abundance and protein accumulation of TR-ACO2 were also observed in the lateral roots when compared to the main roots. Histochemical GUS staining of roots of a single genetically-independent line transformed with a TR-ACO2p::GUS construct showed predominant promoter activity in the mature tissues of both the main and lateral roots but not in the meristematic tissues. In contrast, TR-ACO3 showed greater transcript abundance in the main roots relative to the lateral roots, and the promoter activity, as determined using a single genetically- independent line of TR-ACO3p::GUS transformed plants was predominantly in the mature tissues of the main roots In response to Pi depletion, the members of TR-ACO gene family were temporally expressed in the white clover roots. Using sqRT-PCR, the TR-ACO1 transcript abundance was greater in Pi depleted roots at 12 h and 24 h after Pi depletion in both wild type plants and in the one genetically-independent line of white clover transformed with the TR-ACO1p::mGFP5-ER construct examined. Similarly, by western analysis using both a-TR-ACO1 and commercially available a-GFP antibodies (for the transformed line), a greater accumulation of proteins was consistently observed in Pi depleted roots from the first up to the seventh day after Pi depletion. By confocal microscopy, it was determined for several genetically-independent line of white clover transformed with TR-ACO1p::mGFP5-ER that under Pi depletion more intense GFP fluorescence over a time course of 1 d, 4 d, and 7 d was observed, when compared to plants grown under Pi sufficiency. For TR-ACO2, there was no significant difference in transcript accumulation and protein accumulation in response to short term Pi depletion of up to seven days. However, at 15 d and 21 d after Pi depletion there was a greater protein accumulation in the roots of Pi depleted plants relative to the Pi sufficient roots. Further, when main and lateral roots were compared, a greater protein accumulation occurred in the lateral roots. For TR-ACO3, there was no consistent trend of transcript accumulation in response to Pi depletion over a 24 h period. While a marked reduction in transcript accumulation was noted in Pi depleted roots at 1h, 12 h, 24 h, there was an increase in transcript accumulation at 6 h and 18 h after Pi depletion, indicating that factors other than Pi supply may be affecting gene regulation. Root morphological studies revealed an increase in the main root length and lateral root production in white clover in response to Pi depletion with a greatest growth rate noted between the sixth and ninth day after Pi depletion, and this period overlapped with accumulation of TR-ACO1 protein suggesting a role for ethylene in the Pi stress induced lateral root production in white clover. The differential regulation of the three TR-ACO genes in white clover roots in response to Pi depletion further suggests the divergence in terms of regulation of the ethylene biosynthetic pathway, which may play an important role in fine tuning the responses of plants to particular environmental cues.
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Monthly house price indices and their applications in New Zealand : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy, Department of Economics and Finance, College of Business, Massey University
Shi, Song (2009)
Doctoral thesis
Massey UniversityDeveloping timely and reliable house price indices is of interest worldwide, because these measures influence consumer behaviour, inflation targeting, and spot and futures markets. Several techniques for constructing a constant quality price index are available in the literature, but these methods are difficult to apply in localities where market transaction data is limited. Since house price movements are a local phenomena, improving the timeliness of a quality controlled price index at local housing market levels in small countries like New Zealand is a challenge. This thesis comprises three essays that focused on improving the timeliness of reported house price indices at the local market levels. The timeliness issue examined in this thesis has not previously been rigorously investigated and this makes the results of this thesis both important and unique for the benefit of both academic research and practical application. Essay One reviews the sale price appraisal ratio (SPAR) method, which has been applied since the 1960s for producing local house price indices at a semi-annual and quarterly basis in New Zealand. Utilizing a variety of statistical tests and comparing this index with the repeat sales and median price index result in the study highlighting the potential of, as well as the problems associated with, a price index produced by the SPAR method at a monthly level. In the following two essays, monthly price indices are tested using empirical real estate research methods in order to examine their usefulness in exploring the research questions as well as revealing the statistical differences between them. Essay Two studies the relationship between sale price and trading volume, and the ripple effect of local house price comovements. The results show that the trading volume generally leads the sale price in the long-run and the ripple effect is most likely constrained within regions. In Essay Two, the monthly SPAR index produces similar statistical results to those estimated by the repeat sales index for large cities. Essay Three is a study on the market efficiency of housing markets. It is found the local housing market is neither weak-form nor semi-strong form efficient. Local house price movements are strongly correlated and are mean reverting towards their long-run equilibrium. It is further concluded that monthly price indices for small cities are problematic due to the problem of small sample size. Overall, the findings in this thesis show monthly house price indices can be generated by using the SPAR method at local market levels. However, this potential is limited to large cities. Further research can focus on improving the quality of monthly price indices for large cities.
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The molecular and cellular characterisation of the first glycocin, plantaricin KW30 : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biochemistry at Massey University, Palmerston North, New Zealand
Stepper, Judith (2010)
Doctoral thesis
Massey UniversityBacteriocins, typically secreted by Gram-positive and -negative bacteria, are ribosomallysynthesised antimicrobial peptides which inhibit the growth of competing bacteria. We have purified a 43 amino acid bacteriocin, plantaricin KW30 (PlnKW30) produced byLactobacillus plantarum KW30, that has little amino acid sequence similarity to any other characterised bacteriocin. The gene encoding plnKW30 is in a cluster with the genes required for maturation and export of, and immunity to, the bacteriocin. This arrangement of genes is similar to the genomic context of bacteriocin genes in other lactic acid bacteria. The plnKW30 gene cluster comprises six genes encoding a glycosyltransferase, a proteolytic ABC-transporter, twoputative thioredoxins, a response regulator and PlnKW30 itself. PlnKW30 was found to possess two unusual post-translational modifications: an O-glycosylated serine and an unprecedented S-glycosylation of the C-terminal cysteine. The modified serine is located on an eight residue loop that is tethered by a disulfide bridge. Bothmodifications have been identified as N-acetylglucosamines (GlcNAc), making PlnKW30 thefirst described class IV bacteriocin. A post-translational modification with S-linked GlcNAc isunprecedented in bacteriocins as well as in all genera. The antimicrobial activity of PlnKW30 on L. plantarum ATCC 8014 was analysed using enzymatic dissection coupled withbioassays. It was found to be concentration dependent and both the N-and C-terminalfragments are necessary for activity. Furthermore, reduction of the disulfide bonds results in abolishment of antimicrobial activity and it appears that deglycosylation of the serine 18 decreases the antimicrobial activity by about two thirds. These results show that all posttranslational modifications contribute to the antimicrobial activity of PlnKW30. The addition of N-acetylglucosamine to cultures of the indicator strain L. plantarum ATCC 8014 protects it from the antimicrobial effect of the added PlnKW30. PlnKW30 probably targets an N-acetylglucosamine transporter in the target cell membrane, similar to the mannose phosphotransferase system targeted by lactococcin A.
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