1,354 results for Masters, 2011

  • Molecular and bioinformatic analysis of the perA locus in Epichloë : this thesis is presented as a partial fulfilment of the requirements for the degree of Master of Science (M.Sc.) in Genetics at Massey University, Palmerston North, New Zealand

    Berry, Daniel (2011)

    Masters thesis
    Massey University

    Fungal endophytes of the Epichloë genus form largely mutualistic symbioses with coolseason grasses, systemically colonising the intercellular spaces of the host in a strictly regulated fashion. The endophyte receives protection and sustenance from the host, and in return provides benefits such as increased growth, drought resistance and protection against herbivores. Protection against herbivory is mediated through the production of bio-protective fungal secondary metabolites (SM). Examples of these SMs include lolitrem B, the causative agent of ‘ryegrass staggers’ in stock, and the insect feeding deterrent peramine. The genes responsible for the production of each of these SMs are usually found clustered together in the genome, and are often closely associated with a range of transposon relics. SM gene expression occurs only when the endophyte is growing in planta, indicating the presence of plant-fungal signalling. This study investigated the locus structure and organisation of the gene perA that encodes the non-ribosomal peptide synthetase PerA, which is both essential and sufficient for production of peramine. It was found that perA and its flanking intergenic sequences exhibit considerable transposon-mediated variability across Epichloë, and that this transposon activity is likely responsible for the taxonomically discontinuous production of peramine both within and across Epichloë spp. The major facilitator superfamily transporter gene EF102 is divergently transcribed from and co-regulated with perA (EF103). Transcriptome data were used to identify transcription start sites for both genes. Comparative analysis of the intergenic sequence separating EF102/perA from 10 Epichloë isolates covering six different species refined the perA translation start site, and identified conserved regions in the promoters of both genes proposed to be important for regulation. A motif search identified a conserved DNA motif present multiple times in the promoters of both genes. Deletion analysis of EF102 revealed the gene probably does not encode a peramine transporter, as was hypothesised; however the four independent ΔEF102 mutants exhibited a reduction in peramine production relative to wild type, resulting in an alternative hypothesis that EF102 encodes a transporter for a PerA substrate precursor molecule such as glutamate.

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  • Parent and teacher knowledge of head injuries : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University

    McKay, Erin Anne (2011)

    Masters thesis
    Massey University

    This study examined parents and teachers knowledge of aspects of head injury (HI). Part one examined the various sources of information and education parents and teachers have access to that could impact on their knowledge of HI. Part two surveyed 64 parents and 64 teachers of young children (s knowledge of HI. A more complete form of the survey could be used to get a well rounded picture of the current knowledge base of HI.

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  • Factors affecting cassava adoption in Southern Province of Zambia : a case study of Mazabuka District : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agri-Commerce at Massey University, New Zealand

    Phiri, Tionenji (2011)

    Masters thesis
    Massey University

    Southern Province of Zambia is a drought prone area and the main crop that is grown is maize which requires a high amount of rainfall. As a result maize does not do well in the area and there are frequent food shortages. The Government and Non- Governmental Organisations (NGOs) have been promoting cassava technology which is drought tolerant to improve the food security in the area. However, the adoption of cassava technologies has been low. The findings of this study will inform the development of more effective strategies to improve food security in southern province of Zambia and it has done this by exploring the cassava promotion programme. A single case study was used to investigate the factors that affect cassava adoption in Mazabuka district. Purposive and snowball sampling methods were used to select participants for interviews and observations. 40 farmers who included opinion leaders and 6 key informants were interviewed. The data was analysed using qualitative data methods. The results of the study indicated that although a small number of farmers continue to grow cassava, the cassava promotion programme was a flawed programme because cassava did not meet the needs of the majority of the farmers. There was a mix of complex and interrelated factors that affected the adoption of cassava. These included internal and external factors to the farm and farm household and those related specifically to the characteristics of cassava relative to the farmers’ existing crop of maize. Cassava is a substitute crop to maize. The result of the study indicated that the farmers’ adoption decision was based on the fact that they wanted a crop that would not only meet their food needs but also income. Cassava is a substitute crop and the farmers compared it with maize, an existing crop, which provided them with both food and income. Processing facilities and a market supported by government policy existed for maize and not for cassava. Land tenure was the internal factor, but not as a result of the length of time the lease was held, but because of the conditions imposed on the leasers in terms of crops they were able to grow. The most important factors were external factors and these included government policy and an aspect of extension service delivery. A competitive government policy that supported processing and marketing facilities for maize, undermined cassava, for which there was no processing facilities and only a small local market. Lack of training and knowledge amongst the local government agricultural extension personnel as to how to grow and process cassava impacted also on farmers’ knowledge and hence adoption of cassava. Although the inputs for growing cassava were provided for free, they were supplied at the wrong time and this impacted also on farmers’ willingness to grow the crop. The research highlights the importance of using bottom-up and not top down approaches in food security programmes. The results suggest that it is important for food security policy and development interventions to understand the needs of farmers in terms of food, income and livelihoods.

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  • Factors affecting sustainability of agricultural cooperatives : lessons from Malawi : a thesis presented in partial fulfillment of the requirements for the degree of Master of AgriCommerce at Massey University, New Zealand, March, 2011

    Nkhoma, Agnes Towera (2011)

    Masters thesis
    Massey University

    Incorporation of small-scale farmers into agricultural commercialization has led rural communities to form cooperatives for better access to markets. However, sustainability of these cooperatives has been a great challenge. This thesis explores the sustainability problems affecting agricultural cooperatives in Malawi, and develops testable proposition for use on a larger sample. A multiple case study was used to investigate factors that contribute to the unsuccessful performance of agricultural cooperatives. Four cooperatives were selected by a combination of market failure and a-priori sustainability criteria. Basing on the market failure assumptions two cooperatives, from a district close to the major city of Lilongwe and two from a district far away from the city, were selected. In each district one sustainable and one less sustainable cooperative were selected based on the ranking prepared by Ministry of Agriculture and Food Security. The sample was further validated by the experts from local NGOs. Sixteen face to face interviews were conducted on location. Members of cooperatives, board members, the management of cooperatives and key informants were interviewed. It was found that most farmers joined cooperatives to improve their livelihood, through better access to capital and product markets, and for family food security. The farmers have managed to obtain input loans at small scale, despite their dissatisfaction with their cooperatives failure to access product markets. The general consensus for the participants in all the four cooperatives was that in their current state these cooperatives are not sustainable. Although, all the members interviewed were satisfied with the idea of having a cooperative and perceived it to be a good idea for addressing their needs, they were skeptical of their survival. The participants highlighted lack of market access, poor governance and a lack of managerial skills as the main problems affecting their cooperatives. These problems are aggravated by the complexity of the market environment in which these cooperatives are operating, that underscores the significance of the managerial capabilities and the cooperatives capacities. The study indicated that Malawian agricultural cooperatives are essential but still need a lot more support in the area of produce marketing. These findings draws propositions in relation to factors which led to Malawian agricultural cooperatives sustainability problems that can later be tested on a large sample in the other parts of the country or region. From such experiences and lessons, it is recommended to establish an apex organisation or secondary level cooperative at district level to address governance, management and market access problems, in order to improve the performance of cooperatives. Further, community sensitization is needed to increase memberships. In addition, policy interventions such as provision of the infrastructure necessary for accessing market information and supportive regulatory framework that would allow competitive market environment.

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  • A field investigation into the relationship between LA90 and LAeq wind turbine sound level descriptors in New Zealand : a thesis presented in part fulfilment of the requirements for the degree of Master of Philosophy (Science) majoring in Environmental Acoustics at Massey University, Wellington, New Zealand

    Hannah, Lindsay John (2011)

    Masters thesis
    Massey University

    Wind turbine generator acoustics is an issue for communities as it is people within these communities that occupy dwellings. The current New Zealand wind turbine standard NZS6808:2010 Acoustics – Wind Farm Noise, places priority on received sound pressure levels at dwellings remote from the wind turbine rather than from sound emission at the wind turbine generator itself. As part of assessment under NZS6808:2010, background noise levels are required to be measured [as LA90] at selected relevant receiving locations off site before a wind farm site can be developed. Allowable wind turbine design sound limits are then derived [as LAeq] from a comparison of the predicted wind turbine sound pressure levels and the actual measured average background noise at the nominated off site receiving location[s]. A disparity arises with the use of two different sound level descriptors used for assessment under the standard, namely the statistical LA90 versus the LAeq energy average sound level descriptors. In order to account for the possible variation between the LA90 and LAeq sound level descriptors NZS6808:2010 requires LAeq predicted sound pressure levels to be ‘converted’ to received LA90 sound pressure levels as part of the acoustic prediction process and hence NZS6808:2010 states the predicted LAeq sound pressure levels at any receiver location are to be treated as equivalent to the LA90 value. At the time of commencing this study the [then] current New Zealand wind turbine standard NZS6808:1998 Acoustics – The Assessment and Measurement of Sound from Wind Turbine Generators stated that background noise levels were ‘typically 1.5 dB to 2.5 dB’ lower than the predicted LAeq sound pressure levels for wind turbine generator sound. Unlike the current standard, NZS6808:1998 did not provide any means to account for the disparity between the background noise levels and predicted wind farm sound levels as part of the wind farm assessment process. A key implication being that under NZS6808:1998 wind turbine sound could potentially exceed the allowable 40 dBA design sound limit [or average background noise level + 5 dB] by up to a further 2.5 dB and still remain in compliance with the limits recommended under the NZS6808:1998. The impetus and motivation behind this study has consequently been to endeavour to quantify the variability between wind turbine generator sound descriptors [LAeq and LA90] both on the wind farm site and at a remote receiver dwelling location where people actually reside. The research outcome is relevant as at the time of commencing this thesis NZS6808:1998 was being reviewed by experts and practitioners in the area of wind turbine acoustics. This review included assessing any differences in sound level descriptors. This review provided the incentive for the thesis being particularly valuable, unique and practical so far as any actual measured field results were relative to wind turbine generators in New Zealand and the New Zealand Standards operating environment. In order to carry out the evaluation between LAeq and LA90 sound level descriptors an assessment based around a semi-empirical field study of objective field measurements and subjective observations was conducted at two wind farms in the lower North Island of New Zealand. The study assessed present day, commercial class, horizontal, three bladed wind turbine generators located over heterogeneous terrain. The principal implication of the study related to the collection of uncontaminated wind turbine sound level samples. A raw data set of 11,150 [10 minute LAeq/LA90 sound level samples] were collected over a 12 month period. From the total sample, merely 39 [or less than 2% of the total raw sample] were actual uncontaminated wind turbine sound samples only. The conclusion here is that due to the high number of intervening variables it is a challenge to collect a large sample set of uncontaminated wind turbine sound data. Based on the data collected, it could potentially take several years to collect a suitable uncontaminated sample of say 1,500 [10 minute samples] from wind turbine sound only at remote locations off the wind farm site using such methods. Data collection and analysis was not an issue on the wind farm site itself due to the measurement location and wind turbine being in close proximity. The results of the field study illustrated that based on the final data set of 10 minutes sound level sampling [n=39] the overall mean sound level difference [LAeq - LA90] for wind turbine sound was 2.4 dB at a remote residential location some 1200m from the wind farm site. The overall mean sound level difference for wind turbine sound levels based on the wind farm was 1.4 dB [at the nominated Ro location]. As a result of the study’s findings it is concluded that although the field data indicated a quantifiable level difference between the two sound level descriptors the current wind turbine noise standard [NZS6808:2010] rightly removes any uncertainties by stating that LAeq = LA90 when carrying out the assessment process. Therefore the removal of any uncertainty is chiefly due to the fact that although a quantifiable level difference between the two sound level descriptors was achieved for this study the sound level difference is prone to change and any precise or exact level difference is therefore a factor of the wind turbine generator models tested site conditions and related intervening variables.

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  • Offsite manufacturing as a means of improving productivity in New Zealand construction industry : key barriers to adoption and improvement measures : a research thesis submitted in fulfilment of the requirements for the degree of Masters of Construction Management at Massey University, Albany, New Zealand

    Shahzad, Wajiha Mohsin (2011)

    Masters thesis
    Massey University

    Off-site manufacturing (OSM) of building components could be leveraged to improve the reported low productivity trend in the New Zealand (NZ) construction industry. Despite the numerous known benefits of OSM, the uptake of the technology in the industry has been discouragingly low. Previous studies offer little help in terms of prioritising identified barriers to the uptake of OSM. As a result, improvement efforts have been daunted by numerous barriers in the face of limited resources. This study aims to contribute to bridging the gap in the extant literature by identifying and prioritising the key constraints to the industry-wide uptake of prefabrication and the improvement measures. Through a nation-wide survey of consultants, contractors, employers and manufacturers, feedback was received and analysed using the multiattribute analytical technique. Results show that the broad categories of constraints to the adoption of prefabrication in NZ are (in order of decreasing impact and relative contributions): industry and market culture (16.2%), skills and knowledge (15.5%), logistics and site operations (14.8%), cost/value/productivity (14%), supply chain and procurement (13.7%), process and programme (13.6%), and regulatory (12.2%). The subcomponents of the broad constraint categories and their relative levels of impact on the uptake of the technology were reported. In addition to addressing the key barriers identified in the study, further measures for improving the uptake of the technology in New Zealand include promotion by client through specifying OSM in the design briefs, improved education and training on the use of OSM, more marketing/ awareness campaign on the benefits of the technology and better supply chain management and transportation logistics. To enable a methodical evaluation of the marginal value achievable by the use of a variant of OSM over and above that of the traditional stick-built system at the design and life-cycle phases of the procurement process, a decision support model was developed. The model incorporates the key performance indicators (KP1s) underlying clients’ value system at the development and operational phases and compares the extent to which each variant of OSM delivers each value criterion relative to the conventional system. The sum of the marginal values at each phase of the procurement iii | P a g e system provides the rationale basis for choosing either the OSM variant or the conventional system based on the approach that delivers the highest marginal value. The model application to real life project was demonstrated using the modular variant of the OSM compared to the conventional stick-built system. Results of the model application at the development phase shows that the OSM was more beneficial to the client than the conventional system with an overall marginal value of 34% relative to the conventional construction approach. Individual results showed 22% improvement in the completion time for the project, 9% improvement in quality and 3% reduction in the carbon footprint at the development phase. However, the technology was found to be 2.4% more expensive than the traditional stick-built system. Results of the model application at the operation and life-cycle phases also show that the technology achieved superior value compared to the conventional stick-built system. The overall marginal value achieved by the modular OSM application at the operation phase was 49% compared to the traditional stick-built system; this comprised 23% reduction in the running and maintenance costs, 18% reduction in the maintenance frequency of the structure and fabric, and an annual 8% reduction in the carbon footprint. Overall, the use of modular variant of the OSM was found to deliver superior value to clients compared to the conventional system at the development, operational and lifecycle phases of the procurement process.

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  • An integrated literature review of the role of the nurse practitioner in the emergency department

    Eden, Sheryl M (2011)

    Masters thesis
    University of Otago

    A dissertation in partial fulfilment of Master [of] Health Sciences (Clinical) through [the] University of Otago, [Dunedin, New Zealand]. Description: v, 115 leaves : forms ; 30 cm. Notes: "January 2011." Thesis (MHealSc)--University of Otago, 2011. Includes bibliographical references.

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  • An Exploration into Sponsor Relations: How Value is Perceived by Businesses in Art Sponsorship Relationships

    Tyrie, Anna (2011)

    Masters thesis
    University of Otago

    While a vast number of studies have explored exchange dimensions between two entities as a means of value extraction, little attention has been paid to the value which an organisation can receive from a sponsorship relationship. Current literature provides relatively little insight into the sponsorship exchange relationship, particularly that within the arts sector. Reports suggest that the art sponsorship sector will grow a further 40% between 2008 and 2012, prompting that further information is required (Key Note, 2007). The purpose of this research is to gain insight into whether the relationship influences and affects value derived from a sponsorship, as perceived by the sponsoring business. The Literature review provides a comprehensive overview of the literature pertaining to sponsorship and social exchange theory. The review explains the relevance of exchange and social exchange theory, as means of understanding how the relationship influences upon and effects relations between two exchanging parties. Through this process, a gap in knowledge was identified which guided the primary research. The research applied a qualitative, exploratory manner, in order to explore business perceptions of their art sponsorship relationship(s). The research involved interviewing seven businesses, from a range of industries and sizes, on their perceptions and experiences with art sponsorship. The interviews were transcribed and coded, after which a thematic analysis was applied in order to generate meaningful patterns. This process identified five categories which reflected the data and the research objectives. The findings suggest that the perceived value within a firm’s art sponsorship is heavily reliant upon the relationship, where value is derived through the culmination of various areas such as a firm’s motivations, expectations, practices, experiences and perceptions. The thesis provides several models which explain how value is derived and how value derivation alludes to greater ideas, like the lifecycle of a sponsorship relationship.

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  • Are we learning from past practice: The potential for follow-up as an environmental management tool in New Zealand

    Rendall, Chris (2011)

    Masters thesis
    University of Otago

    All development has the potential to cause adverse effects to the environment. Worldwide, environmental concern regarding these effects has significantly increased over the past forty years. This has led to the implementation of environmental legislation and associated requirements for Impact Assessment (IA). The effectiveness of this legislation and other aspects of the effects management framework in protecting the environment have, however, been questioned. The current research firstly examined IA, to identify whether this process was capable of achieving desired environmental outcomes. It found that a primary factor in determining if IA could be an environmental management tool depends on whether follow-up is included in this process. Namely, this includes the use of monitoring, auditing, management and communication of the actual effects of a development. This research highlighted that the IA process can achieve desired environmental outcomes but that it relies on legislation, policy and political support to be effective. In New Zealand, the environmental effects of development are managed, primarily through the Resource Management Act 1991 (RMA). This process was examined and it was identified that while the RMA provides requirements for environmental management, through the use of monitoring and management provisions, these are seldom used by local authorities. Therefore, the environmental effects of development are not currently being effectively managed. This conclusion was supported by key informants’ comments. However, the literature on planning documents and the effectiveness of Assessments of Effects on the Environment (AEEs) indicated that the quality of both have improved since the implementation of the RMA. In New Zealand, the primary means of identifying ways to mitigate environmental effects is through an AEEs, which provide IA in New Zealand. As noted above, follow-up is a key element of an effective IA process. The only component of follow-up that is commonly used in New Zealand is monitoring, which is not used to assess the actual effects of the development but rather, to ensure compliance with consent conditions. A number of key informants identified that currently, the environmental effects of development are not effectively managed and many considered that the application of follow-up would assist in improving such management. Questions on how and in what contexts follow-up should be implemented elicited a broad range of responses from key informants, and these responses appeared to link to their areas of work. Those involved in urban development stated that the overall effects (i.e. plan effectiveness, and general detractions from environmental quality) were key areas to be followed-up. However, key informants involved in large scale developments considered that follow-up should occur as part of the project development/implementation process thus allowing ongoing management. The range of opinions highlights that further research would need to be undertaken before any modifications are made to Schedule 4 or plan monitoring requirements of the RMA. This research outlines that while individuals at local authorities know their job well, they may not understand the complexities and wide ranging effects of large developments. This is further impacted by the siloed nature of planning departments. The research suggests that the use of a more integrated approach to effects management may be required. Oversight committees consisting of representatives of stakeholder groups, like that established for the BHPB Etaki Mine, may be the solution to these management issues.

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  • Controls on slope-to-channel sediment coupling in a small, largely deglacierized alpine catchment, Southern Alps, New Zealand.

    Beel, Casey Robert (2011)

    Masters thesis
    University of Otago

    Channel sediment transfer patterns in alpine environments are an integrated signal that reflects both channel sediment sources and sediment input from extra-channel slopes. The degree of slope-to-channel sediment connectivity is controlled by several factors, amongst them differences in the magnitude and frequency of rainfall events, particle size, sediment availability and surface maturity. However, there has been limited work on the development of slope-to-channel coupling in deglaciated alpine environments over time. Characterising the controls on slope-to-channel connectivity in this environment may result in a better understanding of how landscapes ‘relax’ from perturbation. Channel turbidity was measured using custom built iHOBS turbidimeters at two gauging stations, one above a hydrologically connected slope and one below it in the c. 10 km2 Hoophorn Valley, a largely deglacierised basin in the Southern Alps, New Zealand. On this hydrologically connected slope an array of 30 erosion pins was used to measure surface lowering rates on the slope and eight custom built Gerlach troughs were installed in ephemeral slope channels to trap surficial material mobilized during rainfall events. Discharge-suspended sediment concentration hysteresis patterns at the two gauging stations in the main stream channel were used to indirectly infer sediment coupling between the hydrologically connected slope and the main stream. During the study period, a total of 948 t of suspended sediment was transported through the channel at the upstream site and 715 t through the channel at the downstream site. During rainfall events, episodes of high discharge resulted in transfer of 75% of the total suspended sediment load through the upstream site and 50% through the downstream site. The total mass of sediment eroded from the dissected slope was estimated to be c. 3 t for the study period. Sediment mobilisation was confined to rainfall events with increasing particle sizes trapped with increasing event magnitude. Less than 1% of the particle size distribution of all samples collected during these events was classed as fine sediment, suggesting these sediment sources on the slope were exhausted. Channel suspended sediment transfer patterns during rainfall events were dominated by clockwise hysteresis where sediment concentration peaked before discharge. This pattern was interpreted as representing short distance remobilisation of fine sediment from within the channel, supporting the likelihood of limited input of fines from slopes. The data suggests, therefore, that slope-to-channel connectivity in this environment is dominated by coarse sediment, where there is active coupling. The lack of fine sediment sources on slopes within the basin suggest that since deglaciation there has been a relative decline in fine sediment slope-to-channel connectivity due to source exhaustion and a shift to episodic coarse sediment connectivity. This shift is likely associated with a contemporaneous change from a glacial control on fine sediment production and runoff to a rainfall controlled system, where mechanical weathering of bedrock continues to produce coarse material for transport from slopes to channels.

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  • Training and detraining effects on familial insulin resistance, muscle fibre type, and performance

    Schofield, Katherine L (2011)

    Masters thesis
    University of Otago

    Introduction: Chronic hyperinsulinemia affects muscle, and may advantage speed and power athletes. Hyperinsulinaemia is associated with shifts in expression of myosin heavy chain isoforms, and muscle fibre type resulting in a faster contractile profile (I→IIa→IIb). Insulin sensitivity increases with endurance training, however, there are limited studies on insulin sensitivity with resistance training and detraining. The aims of the present study were to examine insulin sensitivity, skeletal muscle transitions and strength in offspring of Type 2 diabetics, in comparison with normal control subjects, after resistance training and detraining. Method: Six (1 male, 5 female; 21.3 ± 1.8 yr, 164.7 ± 4.6 cm, 62.2 ± 7.1 kg, body mass index (BMI) 22.3 ± 2.5, mean ± SD) familial insulin resistant (FIR) and 10 (4 male, 6 female; 23.0 ± 2.9 yr, 170.1 ± 10.4 cm, 70.0 ± 13.2 kg, BMI 23.8 ± 2.6, mean ± SD) controls (C) completed 9 wk of resistance training (squat, leg press, leg extension, leg curl and box jump exercises) and 9 wk detraining. Measures at baseline (T1), after training (T2) and after detraining (T3) included an oral glucose tolerance test, muscle biopsy and performance tests (3RM; standing squat jump [SSJ], Wingate test, and a force-velocity curve [FVC]). Mixed model and correlation analyses were conducted. Results: There was a significant increase in 3RM values in all exercises, vertical jump (SSJ) and peak power output (PPO) from T1 to T2 (p < 0.05). FVC moved up and right with training (p < 0.05). No significant fibre type changes occurred with training in either C or FIR. FIR reduced insulin area under the curve (AUC) to a greater extent than C with training (65.7 ± 43.4 to 43.4 ± 15.1 vs. 32.7 ± 13.3 to 32.9 ± 14.0 pmol.ml.min-1, resp., p = 0.05). There were reductions in 3RM in all exercises, with detraining (p < 0.001), and decreases in peak moment of force in FVC (p < 0.001), but no change in SSJ and PPO (p = 0.097, p = 0.439, resp.). Detraining decreased percentage type I and increased percentage type II fibres (p = 0.005, p = 0.031, resp.), although no differences in fibre type adaptations or performance were observed between groups. Detraining increased percentage MHC IIx (p = 0.026) and insulin AUC (p = 0.031), with a larger insulin AUC in FIR than in C (p = 0.018). Conclusions: Resistance training produces similar increases in strength in both FIR and C, and decreases in strength with detraining. However, FIR exhibit a greater training effect to reduce insulin AUC and, in contrast to controls, an increase with detraining. While this population did not show clinical signs of diabetes, resistance training can increase insulin sensitivity and may reduce future risk of Type 2 diabetes amongst individuals with mild familial insulin resistance.

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  • Niche partitioning in the Fiordland wrasse guild

    Davis, Jean (2011)

    Masters thesis
    University of Otago

    Investigating the parameters of niche space for marine organisms is useful for identifying their place in the food web and understanding community dynamics. The range of biological and physical gradients found along the fiord axis in Fiordland, NZ offer a unique setting that is well suited for defining aspects of niche space. The purpose of this thesis was to define the characteristics of niche space of four common species of wrasse found in Fiordland, including spotties (Notolabrus celidotus), scarlet wrasse (Pseudolabrus miles), banded wrasse (Notolabrus fucicola) and girdled wrasse (Notolabrus cinctus). Fish were sampled from three paired inner and outer fiord sites in Doubtful Sound, Thompson/Bradshaw Sound and Dusky Sound. Gut contents analysis, stable isotope analysis and morphological analysis of facial features associated with foraging strategy were applied in an effort to characterize diet as an indicator of biological niche space. Fiordland-wide SCUBA surveys of abundance and distribution were correlated with both physical and biological gradients to observe evidence of habitat partitioning. Finally, age and growth analysis was evaluated to assess evidence of trade-offs in life history strategy. Based on these indicators, spotties were found to occupy a significantly different niche space than scarlet wrasse, banded wrasse and girdled wrasse. High niche overlap was found among these other species, with some differences in prey field and microhabitat partitioning. This pattern is mainly attributed to the fact that spotties were observed to be a highly plastic species (generalist), exploiting a wide range of resources over the length of the fiord axis. Conversely, other wrasse species exploited a relatively narrow range of resources (specialists), preferring highly productive kelp forest habitat near the outer coast. Spotties were found to partition niche space between inner and outer fiord environments, consuming a less nutritious diet in the inner fiord by exploiting both terrestrial sources of carbon and alternate trophic levels. In conclusion, the role of wrasse species as pervasive, abundant invertebrate predators in the Fiordland ecosystem indicates they likely play an important role in maintaining ecosystem structure. Though niche partitioning occurred among species and over spatial gradients, outer coast areas appeared to support the most valuable, high quality habitat for Fiordland wrasse species.

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  • Epidemiological validation of a Malay version of the Child Perceptions Questionnaire (CPQ11-14) in Brunei

    Haji Mohamed, Haji Amirul Rizan (2011)

    Masters thesis
    University of Otago

    Background: Oral health-related quality of life (OHRQoL) instruments are being used with increasing frequency in oral health surveys. One such instrument is the Child Perceptions Questionnaire (CPQ11-14), developed in Toronto as a measure of OHRQoL specifically for 11-to-14-year-old children (Jokovic et al, 2002). It aims to improve the description of children's oral health, while taking into consideration the importance of psychological aspects in the concept of health. As the original version of this questionnaire was considered long (37 items), shorter forms were developed with 8 and 16 items to facilitate its use in the clinical settings and population-based oral health surveys (Jokovic et al, 2006). The developers of the CPQ¬11-14 have determined the psychometric properties of the long-form and the short-forms CPQ¬11-14 to be satisfactory, but state that these measures must be validated and employed in other cultures, involving clinical and population-based samples of children and adolescents in different countries. The short-form measure has been tested and validated in a representative population sample of schoolchildren in New Zealand (Foster Page et al, 2008). On the other hand, the long-form CPQ11-14 has been shown to be valid and reliable in a number of different countries including Canada, the United Kingdom, New Zealand, Uganda, Saudi Arabia, Australia, Brazil, Hong Kong and Denmark. However, neither the long-form nor the short-form CPQ11-14 has been translated into a Malay (Bahasa Melayu) version and tested in the South-East Asian region. Schoolchildren are the main target group for public oral health services in Brunei. Until now, data on the Brunei population’s oral health included only the clinical status of oral diseases. Although the focus of the Brunei Ministry of Health has shifted from being disease-oriented to emphasising wellness and the maintenance of the quality of life of the population, a measure of OHRQoL appropriate for use in Brunei has not been available. Therefore, the aims of the current study were: 1. to produce a Malay version of the short-form CPQ11-14; 2. to determine the construct validity of the CPQ11-14 in Brunei; and 3. to determine the discriminative validity of the CPQ11-14 by assessing its ability to distinguish between schoolchildren with and without dental caries and malocclusion. Method: Ethical approval was granted by the Medical and Health Research and Ethics Committee, Brunei Ministry of Health. Five hundred and sixty-nine 11-14-year-old (Year 6) children in nine government primary schools were asked to participate. Parents and caregivers of the children in the study sample were then mailed (through their class teachers) an information sheet about the study, together with an enclosed consent form. A Malay version of the short-form CPQ11-14 was derived through a forward-backward translation process. The questionnaire was then piloted on 20 schoolchildren and refined for ease of use. Prior to clinical examination, all participants completed a copy of the Malay short-form CPQ11-14. The children were examined for dental caries experience (using the DMFS) and for malocclusion (using the Dental Aesthetic Index) by a single examiner (ARM). Both clinical data and data from CPQ11-14 were entered into a Microsoft Excel spreadsheet, and subsequently imported into SPSS. The psychometric properties of the Malay short-form CPQ11-14 were evaluated in terms of internal consistency, construct validity and discriminant validity. Test-retest reliability was assessed in a subgroup of these children (n = 48). Results: A total of 457 children (mean age of 11.1 years, range = 10 to 14 years) were examined, giving an effective participation rate of 80.3%. The prevalence of dental caries in the permanent dentition was 44.4%. The mean dmfs and DMFS of deciduous and permanent dentitions were 1.51 (sd, 3.31) and 1.96 (sd, 3.74) respectively. About one-fifth had 4 decayed surfaces in either dentition. The DAI scores ranged from 17 to 91, with a mean of 31.4 (sd, 8.7). The distribution of participants across the four treatment need categories was: minor/none, 24.1%; definite, 37.0%; and severe/handicapping, 38.9%. The overall CPQ11-14-ISF16 score ranged from 0 to 43, with a mean of 16.8 (sd, 8.7). The number with the minimum score was minimal, with only 1.1% having a score of zero and there were no children with the maximum score. Construct validity was satisfactory, demonstrating significant associations between the mean CPQ11-14-ISF16 scores and the global ratings of oral health and overall well-being. The CPQ11-14-ISF16 was able to discriminate between different caries status, and there was a significant association between impact prevalence and the number of untreated decayed tooth surfaces in either dentition. Interestingly, the gradient of the scale scores across categories of orthodontic treatment need was in the opposite direction, whereby those in the ‘minor/none’ category had the highest and those in the ‘severe/handicapping’ category had the lowest mean CPQ11-14-ISF16 score and impact prevalence. The Malay short-form CPQ11-14-ISF16 had excellent internal consistency with a Cronbach’s alpha of 0.97 and test-retest reliability ICC of 0.94. Conclusion: The outcome of this study suggests that the Malay short-form CPQ11-14 is a valid, reliable and practical instrument for measuring OHRQoL in 11-14-year-old Bruneian children, although its ability to discriminate among children across the malocclusion treatment need categories seems to be limited. This provides further evidence of the instrument’s psychometric properties and its cross-cultural use. However, these are preliminary findings based on a convenience sample, and further testing in replicated studies involving clinical and population samples of children in various settings is necessary to establish the measurement sensitivity and discriminative properties of the Malay short-form CPQ11-14.

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  • The Effect of Active Living and Physical Activity on Post-prandial IL-6 and CRP

    Bone, Julia Lizet (2011)

    Masters thesis
    University of Otago

    Aims: Post-prandial increases in inflammatory markers IL-6 and C-reactive protein (CRP) have been observed following high fat and high carbohydrate meals. Inflammation is associated with increased risk of chronic diseases such as cancer. In addition, sedentary behaviour is also associated with negative health outcomes. Meanwhile, elevated IL-6 and CRP have been associated with a negative mood. The study aim was to compare the effects of continuous physical activity to breaks in sedentary behaviour on post-prandial IL-6 and CRP. The secondary aim was to compare the impact of these patterns (as detailed above) on measures of mood states. Methods: Twenty four healthy sedentary participants (15 female, nine male, mean ± SD, age 25.8 ± 5.8 yr, BMI, 23.6 ± 5.0 kg/m2) completed three, 9 h testing days. These were: sedentary (SE), participants remained seated for 9 h; physical activity (PA), participants performed 30 min of exercise at a speed and incline to elicit 60% VO2max prior to the first meal replacement beverage and were then seated for the remainder of the 9 h; active living (AL), participants walked for 1 min 40s every 30 min throughout the day (this equals 30 min of physical activity spread out over 9 h) at the same speed and incline as the PA condition. For each condition participants received three meal replacement beverages at 1, 4 and 7 h. Each meal provided 0.46 g fat/kg BW, 0.54 g protein/kg BW and 1.12 g CHO/kg BW. Venous blood samples were collected at baseline, 4 and 8 h to measure IL-6 and CRP. Mood was assessed using the Brunel University Mood Scale at 0 and 9 h. Results: In the SE and PA conditions there was a post-prandial increase in IL-6 at 4 and 8 h compared to baseline (SE p<0.05). There was no change in CRP from baseline, nor was there a difference between conditions. No correlation existed between mood and CRP. Increases in IL-6 correlated with a more depressed mood. Both PA and SE conditions decreased tension. There was no effect of AL on mood. Conclusions: Interleukin-6 increased 4 and 8 h post-prandially when sedentary. Thirty min of moderate continuous physical activity following an overnight fast and prior to a meal does not decrease the post-prandial IL-6 response. Breaking sedentary behaviour by as little as 1 min 40 s every 30 min attenuates the post-prandial IL-6 response and thereby, may reduce the risk of chronic diseases. Practical applications from these findings include the use of computer prompts or television advertising to promote standing and walking in individuals with desk jobs or when watching television for long periods of time.

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  • Humanitarian aid: for today or tomorrow?

    Stewart-Harding, Emily (2011)

    Masters thesis
    University of Otago

    The purpose of this study is to discover if the concept of humanitarianism has changed significantly in response to the challenges of complex emergencies. To find the answer, this study assessed humanitarian agencies’ responses to the complex emergency in eastern Burma, an area of the world that poses some of the most acute challenges to traditional humanitarianism. ‘Classical’ humanitarian action has historically focused on the delivery of aid to non-combatants affected by conflict, for the immediate relief of suffering. Agencies have been largely successful at aiding vulnerable populations because they have stuck to certain principles. They focused on non-combatants, negotiated access with states, delivered aid according to the criteria of need, were independent and did not interfere in the politics of the conflict. However, changes in the international context, following the end of the cold war, changed the role of humanitarians in conflict; they were elevated as important, often political actors. Ideas of security and development became interlinked. International threats to the West were perceived as arising out of situations of poverty and failing states. Consequently, humanitarian aid budgets increased to address this, as did the number of humanitarian and development agencies working in conflict areas. Concurrently, the post cold war rise in new types of wars produced unprecedented levels of human suffering; nine out of ten deaths were civilians. Classical forms of humanitarian action were ill equipped to deal with these changes, especially new wars. It is in this new context that new forms of ‘political’ humanitarian action developed. Whilst justified in many ways, political humanitarianism is a particular reaction. The argument is that the ‘development as security’ agenda is reflected in the new principles of political humanitarianism. Political humanitarianism differs from classical humanitarianism as it moves from a concern for the immediate relief of suffering, to a concern for the immediate and long-term consequences of relief distribution, and in some cases, it adopts utilitarian ethics. Whilst saving lives is still important, this is defensible only if it ‘does not harm’, focuses on development issues, supports human rights, and is ideally part of a wider political coherence and coordination strategy to bring peace and rebuild societies. These tensions are reflected in the behaviour of relief agencies in Burma. The main overall finding of this study is that in the eastern Burmese context, the concept of traditional humanitarianism as developed by the International Committee for the Red Cross has not changed significantly. However, there are shifts occurring in the ways relief agencies are compelled to live up to the humanitarian obligations. Most Community Based Organisations formed in solidarity with Non-State Actors, this is significant as it entails taking sides. As opposed to the shift being from traditional humanitarian action to political humanitarian action, the move is from solidarity based humanitarian action to an approach based more on classical principles of humanitarian action. These findings reflect those in recent, multi-country studies, which suggest that humanitarians continue to be divided over the limits to which core classical humanitarian principles should be respected.

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  • Biogeochemical Cycling of Zinc in the Whau Estuary (Auckland, New Zealand)

    Sadhu, Ashish (2011)

    Masters thesis
    University of Otago

    The speciation and reactivity of Zn was studied along with eight other trace metals in contaminated estuarine sediments in order to investigate the biogeochemical cycling of Zn in estuarine environment. Metal concentrations were determined for sediments, pore waters and surface waters. The enrichment factors (EF) and trace metal partitioning (Kd) of sediments were also assessed. Sediment samples were collected from two estuaries: the Whau Estuary in Auckland (North Island) and the Kaikorai Estuary in Dunedin (South Island). Concentrations of Zn, Cr, Mn, Fe, Co, Ni, Cu, Cd and Pb were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) after sequential extraction of the sediments. The mineralogical composition of the sediments was determined by X-ray diffractometry (XRD). The adsorption-desorption phenomena of Zn, Cd, Cu and Pb were studied for both oxic and anoxic sediments by using a Freundlich isotherm model. The resulting data were used to predict the potential metal mobility in the estuarine sediments. It has been observed that the total concentration of Zn and other trace metals (Cr, Fe, Cu, Cd, and Pb) but not Mn in the sediments decreased with increasing salinity (i.e. seaward direction). For example, concentrations of Mn, Zn and Pb at the sea end of the Kaikorai Estuary were 383 ± 13, 60 ± 3 and 12 ± 1 ppm, and towards the river end the concentrations were 133 ± 5, 120 ± 6 and 54 ± 3 ppm respectively. In the both Whau Estuary sites the total Zn concentrations in sediments ranged from 74 ± 3 to 353 ± 10 ppm. The Zn concentration in the water of the Whau Stream tributary water was 20.5 ppb at pH 7.03. In surface water of the Whau Estuary the concentration of Zn was 5.61 ppb at pH 7.77 at the river end member, but at the sea end member the concentration at pH 8.01was below the ICP-MS detection limit. In sedimentary pore water of the Whau Estuary the concentration of Zn in three depth layers (0-1, 4-6 and 10-12 cm) ranged from12.3 ppb to 41.4 ppb collected at the river end. The order of release of total metals from surface water and sediments in the Whau Estuary system was varied with increased salinity. The typical enrichment factors of Zn, Cd, Cu and Pb at the river end member of the Whau Estuary were 4.0, 1.9, 3.6 and 3.4, which indicated that moderate enrichment occurred in the sediments. However, at the same site Fe showed the largest distribution coefficient (log Kd) and Cd the smallest, where Zn, Cd, Cu and Pb were in the range of 3.6 to 5.6. The adsorption and desorption phenomena of metals (Cu, Zn,Cd and Pb) on sediments were studied by addition of these metals to determine the effect of salinity gradients and redox potential on the release of Zn and other metals into the soluble phase. A significant amount of Zn and other metals was released under oxidizing conditions while the metals were effectively immobilized in slightly basic and strongly anaerobic conditions. The Freundlich model showed that the adsorption of metal ions to the Mn-Fe oxide and organic fractions of the sediments were controlled by the presence of Mn-Fe oxide and organic matter contents in sediments. The results demonstrated that the affinity of Zn (KF) was significantly greater (51 ± 13 ppm) in oxic fine (100 µm) sediment than in oxic coarse sediments where KF was 15 ± 8.4 ppm. The adsorption affinity in coarse dry oxic sediments decreased in the order of Pb>Cu>Zn>Cd whereas in wet anoxic sediment collected from the same site in the Whau Estuary the KF decreased in the order of Pb>Cu>Cd>Zn. It is concluded that in these estuarine environments the water-particle interactions were important in metal cycling. Studies showed that relative changes occurred in partitioning of Zn between salinity gradients. However, the increased seawater salinity was not the major driver responsible for the release of Zn from sediments. The cycling of Zn from solid phase (adsorbed onto sediment) to the liquid phase (dissolved phase of the water column) was mainly driven by the redox change of Fe and Mn oxy/hydroxides in estuarine systems. The ability of Fe and Mn oxy/hydroxides to retain Zn ions and act as scavenger in estuarine sediments has been confirmed.

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  • Perceived insufficient breastmilk and infant feeding practices for mothers of infants from birth to four months - a mixed methods study

    Harris, Nicola (2011)

    Masters thesis
    University of Otago

    Breastfeeding is seen as a natural and physiological mothering behaviour. Yet breastfeeding is also a health related behaviour, subject to social and cultural influences. Additionally, breastfeeding is an infant care response practised and experienced differently by mothers. Thus mothers feed their infants differently for different contextual reasons. Given the role that perceived insufficient milk appears to have in shortening breastfeeding duration, a better understanding of the experience of perceived insufficient milk and its relationship with breastfeeding duration may identify interventions that could help more mothers exclusively breastfeed to six months. A study using a convergent mixed methods design was conducted. Qualitative and quantitative data were collected in parallel, analysed separately and findings were merged in an integrative phase. In phase I, qualitative data were collected through in-depth, semi-structured interviews with twelve Dunedin mothers who had reported experiencing perceived insufficient milk during their participation in a randomised controlled trial (POI.nz). Phase I investigated the symptoms of (objective 1), responses to (objective 2), and lived experience of (objective 3) perceived insufficient milk. Interviews were transcribed and analysed using a grounded theory approach and the constant comparative method of analysis. In phase II, quantitative data were collected from 114 Dunedin mothers in the control group of POI.nz during pregnancy, and at three, seven, eleven, fifteen and nineteen weeks postpartum to determine: the prevalence of different infant feeding methods iii (objective 4); predictors of exclusive breastfeeding duration and any breastfeeding duration (objectives 5 and 6); the prevalence of perceived insufficient milk (objective 7); and predictors of perceived insufficient milk (objective 8). Predictors of exclusive and any breastfeeding duration were determined using survival analyses and predictors of perceived insufficient milk were analysed using logistic regression. In phase III, quantitative (QUAN) data that complemented the qualitative (QUAL) themes were described, and quantitative results and qualitative results were integrated. Three themes were developed in the qualitative analysis: urgency of the perceived insufficient milk situation, persistence with breastfeeding in spite of perceived insufficient milk, and pressure to breastfeed. Between two and nineteen weeks postpartum the prevalence of exclusive breastfeeding from birth markedly decreased from 73% to 32% and the prevalence of any breastfeeding from birth decreased from 92% to 78%. Perceived insufficient milk was the most frequently provided reason (58%) for introducing non-breastmilk liquids or solids and one of the strongest predictors of a shorter duration of exclusive breastfeeding. More than half of the participants (61%) perceived they had insufficient milk at some time before nineteen weeks. The following factors were predictors of perceived insufficient milk: worry about infant weight gain in the first three weeks, average breastfeed duration at three weeks, the introduction of non-breastmilk liquids or solids before seven weeks, breastfeeding frequency at seven weeks, and rating of infant sleep as a problem at seven weeks. Phase III integrated the qualitative and quantitative results. A mother.s worry about her infant.s inadequate weight gain was important, as it was a symptom of perceived insufficient milk (QUAL and QUAN), a predictor of perceived insufficient milk (QUAN), a predictor of a shorter duration of exclusive breastfeeding (QUAN) and a reason for the introduction of infant formula (QUAL and QUAN). Baby behaviours such as crying were the most common symptoms of perceived insufficient milk (QUAN). Persistence with exclusive or full breastfeeding after perceived insufficient milk was evident in both phases, with 50% (19/38) of mothers exclusively breastfeeding at nineteen weeks having reported perceived insufficient milk at some time (QUAN). This iv sometimes involved mothers changing their breastfeeding practices by breastfeeding more often or expressing breastmilk to increase their milk supply (QUAL and QUAN). Pressure to breastfeed exclusively was evident in both phases and mothers said this resulted in a lack of options, making some mothers angry (QUAL). This pressure was mainly described as coming from health professionals (QUAL). Not all mothers felt angry about the advice they received to keep breastfeeding, as some considered being pushed to continue to breastfeed was the most helpful breastfeeding advice they received (QUAL and QUAN). Perceptions of insufficient milk are very common among breastfeeding mothers and differ from mother to mother. The baby.s behaviour, sleeping patterns or weight gain may cause mothers to question their milk supply with varying degrees of urgency. Not all mothers stop exclusively breastfeeding when they perceive they have insufficient milk suggesting that some mothers are able to manage or overcome their milk supply concerns enough to continue breastfeeding. This finding provided insight into the diversity of mothering practices, a diversity that was further illustrated by mothers. different opinions of breastfeeding advice. Health professionals working with breastfeeding mothers need to know that mothers who are concerned about their baby.s weight before three weeks of age, or their baby.s sleep pattern between three and seven weeks of age are at risk of questioning their milk supply, as are mothers who may be having other problems with their breastfeeding; shown by a longer duration of breastfeeding at three weeks or less frequent breastfeeding at seven weeks. These mothers may need further investigation to determine whether their milk supply is inadequate, and support targeting those issues. However, this study also shows the need to avoid rigid pressure when a mother encounters breastfeeding problems, while also encouraging continuation of exclusively breastfeeding to six months.

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  • Blood pressure and plasma volume responses during recovery: Effect of exercise intensity and exercise limb

    Graham, Matthew John (2011)

    Masters thesis
    University of Otago

    Background: Arterial and central venous blood pressures are reduced following exercise, which contributes to exercise being a key anti-hypertensive therapy and facilitates expansion of blood volume. However, the effects of exercise intensity, duration and exercising limb on post-exercise hypotension and hypervolaemic responses are not resolved. Therefore, the purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) endurance (END) compared with repeated high-intensity exercise (RHIE) performed with the lower body (RHIELower), and (ii) RHIELower compared with the upper body (RHIEUpper). It was hypothesised that post-exercise hypotension and plasma volume expansion would be similar between END and RHIELower, whereas RHIEUpper would stimulate a smaller response compared to RHEILower. Methods: Twelve untrained males (age: 23 ± 3 y; body mass: 72.4 ± 12.8 kg, : 43.6 ± 7.6 mL•kg-1•min-1, mean ± SD) completed one END (50 min at 65% ), one RHIELower and one RHIEUpper exercise trial (both RHIE, five 30-s maximal sprints with 4.5-min recovery) in balanced order, ~2 wk apart. Measurements were taken at baseline, during exercise (cycle ergometry), continuously (beat-to-beat blood pressure) or at 15-min intervals (haemoglobin and haematocrit) throughout the first 3-h seated recovery, then at 8 and 22 h. Responses were modelled for key parameters (e.g., nadir) before inferential analysis for effects of exercise intensity and limb using a pre-post crossover model. Results: RHIELower stimulated a larger post-exercise hypotensive response (AUC) than did END (7540 ± 3853 vs. 3897 ± 2757 mm Hg•min, p=0.05, CI: 20 – 6764 mm Hg•min), whereas similar responses were evident for exercising different limbs (RHIEUpper 6420 ± 3947, p=0.48, CI: -5157 - 2635 mm Hg•min). In contrast, arterial blood pressure at 22 h was reduced after END (-8 ± 8 mm Hg) but not after RHIELower (0 ± 7 mm Hg, p=0.04, CI: 0.6 - 15 mm Hg) or RHIE Upper. Plasma volume expansion at 22 h was similar (CI: -5 – 5%) for END (+5 ± 5%) and RHIELower (+5 ± 5%), as well as for RHIEUpper (5 ± 7%, CI: -8 – 6%). Conclusions: The different post-exercise hypotension responses between endurance and RHIE, implicates peripheral dilatory factors associated with exercise intensity. Yet, the similar hypotensive responses between lower- and upper-body RHIE implicates a central component unrelated to the vascular bed used during the exercise. At 22 h, the decreased blood pressure after endurance exercise indicates that the sympathetic nervous system and stress hormones may still be elevated or that a lack of endothelial function following RHIE may occur. Similar plasma volume expansion 22 h following exercise irrespective of exercise intensity and exercising limb indicates that a variety of exercise regimes might be acceptable in inducing hypervolaemia, and was not obviously related to different hypotensive responses. These findings collectively allow a better comprehension of the training response to different exercise stimuli, along with providing evidence for the use of a variety of exercise regimes that could be used by different populations (hypertensive, time constrained, paraplegic) to access the health benefits of exercise.

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  • The Training and Transfer of Dynamic Decision Making Performance

    Nicholson, Brad Joseph (2011)

    Masters thesis
    University of Otago

    This study investigated the relationship between the cognitive load experienced during training, cognitive ability and previous electronic gaming experience, and the transfer of performance to a novel situation. The training and transfer of dynamic decision making (DDM) performance from one decision making environment to another is critical for the development of effective performance under operational DDM conditions. Cognitive ability was assessed with the standardised measures, Raven’s Standard Progressive Matrices and WOMBAT™ version 4.0, respectively. Electronic gaming experience was measured with a Likert Scale. Next, the computer game called Fire Department 3 was used to simulate various DDM environments. Participants’ practiced completing fire fighting objectives under either low or high conditions of cognitive load and then performed a (transfer) test in an alternative fire fighting environment under an intermediate level of cognitive load. Sixty-three students completed the study. Based on previous findings, it was expected that only the performance of participants who practiced under low cognitive load would improve significantly from the practice phase to the test phase, and the degree of positive transfer would be largest for those with low cognitive ability or no recent gaming experience. It was also predicted that WOMBAT™ test scores would be more predictive of DDM performance than Raven test scores. A repeated measures analysis of covariance (ANCOVA) revealed a significant three-way interaction between test phase (practice and transfer), cognitive load (high or low) and previous electronic gaming experience. As predicted, WOMBAT™ test scores were found to be more predictive of FD3 simulation performance than Raven test scores. Contrary to expectation, the relationship between cognitive load and transfer performance was not significantly related to cognitive ability. Furthermore, the results showed that the mean performance of neither group improved significantly between the practice phase and the test phase. Overall, compared to practicing under high cognitive load, practicing under low cognitive load was associated with better practice phase performance. However, compared to practicing under high cognitive load, practicing under low cognitive load was also associated with a significant reduction in performance on the first transfer test for participants with recent gaming experience, but not for participants without recent gaming experience. The results from a second transfer test, although non-significant, were consistent with the results of the first transfer test. Major implications of the present study are that training conditions which facilitate faster skill acquisition and improved performance during training are not directly related to better transfer performance. It was found that high levels of cognitive load may be used during training to improve transfer performance. However, the interaction between test phase, cognitive load and previous electronic gaming experience shows that, to maximise transfer performance, cognitive load during training must be tailored to the characteristics of different individuals (e.g., level of electronic gaming experience). This study also shows that the WOMBAT™ test appears to have specificity for discriminating between different levels of performance in laboratory and real-world DDM environments.

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  • Ocean acidification and its potential effects on the early life-history of non-calcifying and calcifying echinoderm (Echinodermata) larvae

    Gonzalez Bernat, Maria Jose (2011)

    Masters thesis
    University of Otago

    Ocean acidification, as a result of increased atmospheric CO2, has the potential to adversely affect the larval stages of many marine organisms and hence have profound effects on marine ecosystems. This is the first study of its kind to investigate the effects of ocean acidification on the early life-history stages of three echinoderms species, two asteroids and one irregular echinoid. Potential latitudinal variations on the effects of ocean acidification were also investigated by selecting a polar species (Odontaster validus), a temperate species (Patiriella regularis), and a tropical species (Arachnoides placenta). The effects of reduced seawater pH levels on the fertilization of gametes, larval survival and morphometrics on the aforementioned species were evaluated under experimental conditions. The pH levels considered for this research include ambient seawater (pH 8.1 or pH 8.2), levels predicted for 2100 (pH 7.7 and pH 7.6) and the extreme pH of 7.0, adjusted by bubbling CO2 gas into filtered seawater. Fertilization for Odontaster validus and Patiriella regularis for the predicted scenarios for 2100 was robust, whereas fertilization was significantly reduced in Arachnoides placenta. Larval survival was robust for the three species at pH 7.8, but numbers declined when pH dropped below 7.6. Normal A. placenta larvae developed in pH 7.8, whereas smaller larvae were observed for O. validus and P. regularis under the same pH treatment. Seawater pH levels below 7.6 resulted in smaller and underdeveloped larvae for all three species. The greatest effects were expected for the Antarctic asteroid O. validus but overall the tropical sand dollar A. placenta was the most affected by the reduction in seawater pH. The effects of ocean acidification on the asteroids O. validus and P. regulars, and the sand dollar A. placenta are species-specific. Several parameters, such as taxonomic differences, physiology, genetic makeup and the population’s evolutionary history may have contributed to this variability. This study highlights the vulnerability of the early developmental stages and the complexity of ocean acidification. However, future research is needed to understand the effects at individual, community and ecosystem levels.

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