Otago University Research Archive
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Characterising the Quaternary stratigraphy of the paleovalley underlying Dunedin and Otago Harbour
No full textBeneath the surface of the low-lying densely populated suburbs of Dunedin and the adjacent Otago Harbour is an extensive record of past sea level change over the Quaternary. Prior research into the Quaternary stratigraphy of Dunedin and Otago Harbour is limited with only recent work including seismic lines collected in the harbour and gravity measurements and modelling only being completed in recent years. In this investigation, I use a combination of seismic and sedimentological techniques to identify and constrain paleo sea levels within the subsurface geology of Dunedin and Otago Harbour. This research aims to build a better understanding of near coast highstand environments in this uniquely preserved setting and using this knowledge to better understand the effects of future sea level rise.
Seismic imaging of sediments within Otago Harbour was used to track sea level highstand sedimentary units throughout the subsurface, identified by contrasts in the physical properties of the sediment, causing strong visible reflections. 42 seismic lines were collected in the harbour adjacent to Port Chalmers, imaging to a maximum of 140 m. The seismic images were used to propose and track representative sedimentary horizons, allowing comparison with the CE17/0106 sediment core which reached a depth of 20.7 m collected as part of the New Zealand SeaRise programme in early 2019 and from the Edgar Centre which reached a depth of 45.5 m in South Dunedin in 2016. This work maps five distinct horizontal sedimentary reflections observed within the paleovalley sediments, that coincide with observed changes in lithology within both the CE17/0106 and Edgar Centre cores. Elemental ratios such as Ca/Ti and Br/Inc produced from XRF measurements from core CE17/0106 are used to infer changes in the depositional environment as well as provenance. Radiocarbon ages from the CE17/0106 core provide an age model for the upper 12.4 m constraining it to the last 9 ka. The dated sediments can be tied to the shallowest horizon observed within the seismic record with similarities in the sediments between the CE17/0106 and Edgar Centre Cores.
Below the horizon recovered in core CE17/0106, several more distinctive horizontal sedimentary reflections were observed. These horizons were deposited during sea level highstand events, infilled from the initial erosion of the paleovalley. These horizons lack any signs of past tectonics; however, the deeper horizons show evidence of erosion between highstands, cutting channels through the Quaternary sediments
Determining the role of exercise-induced heat in resistance exercise conditioning
No full textIntroduction: Exercise is known to increase body temperature, but the temperature of exercising muscle is under-examined, particularly in resistance exercise. Muscle temperature is of interest because muscle heating per se can promote hypertrophy and protect against atrophy. The aims of this project were to: (i) characterise muscle temperature responses to typical resistance exercise training regimes, (ii) investigate the feasibility of preventing the muscle temperature rise, and (iii) determine the extent to which exercise-induced heat underpins adaptations from resistance training. The hypotheses were that: i) high repetition, short-rest exercise would be the most thermogenic exercise regimen, and (ii) resistance training with prevention of exercise-induced rises in muscle temperature from the active muscle would attenuate hypertrophic and strength adaptation, when compared to matched training with exercise-induced heat accumulation.
Methods: Two studies were completed. In Study 1, five physically-active participants (two females) undertook three work-matched resistance exercise sessions in randomised order, on separate days. Unilateral bicep curls were used in sessions representing hypertrophy training (3x10 repetitions at 67% 1RM), strength-endurance training (3x20 repetitions at 34% 1RM), and strength training (6x4 repetitions at 84% 1RM). Thereafter, the feasibility of preventing muscle temperature rise during a strength session was assessed using arm immersion in 14°C water for 10 minutes preceding the first exercise set and between each remaining set.
Study 2 was a preliminary study on the effects of muscle temperature on adaptations to resistance exercise. Five healthy non-resistance trained participants (three females) completed a 6-week bicep curl resistance training programme using a contralateral limb-control design. Eighteen strength training sessions (6x4 repetitions at ~80% 1RM) were completed with one arm randomised to train in a cool state (“cool”, as described above) and the other arm training with natural heat accumulation (“warm”).
Results: Study 1: The three regimes increased biceps brachii temperature to a similar extent; 2.0±0.8°C for hypertrophy, 2.5±1.0°C for strength-endurance, and 2.2±0.5°C for strength training (baseline: 35.3±0.8°C; time: p<0.001; condition: p=0.489; interaction: p=0.609). The first third of the exercise session accounted for 46±18%, 62±13% and 60±9% of the total muscle temperature rise for hypertrophy, strength-endurance and strength regimes, respectively (condition: p=0.147). Almost half (44±23%) of the muscle temperature increase was still evident after 15-min recovery, with no effect of condition (condition: p=0.649). Resistance exercise with cooling prevented muscle temperature exceeding its baseline (35.7±0.9°C; post- exercise: 34.6±1.2°C; p=0.164).
Study 2: Peak isometric torque increased in both arms, with no effect of condition (warm: 11±11%; cool 4±7%; time: p=0.033; condition: p=0.310). Bicep curl 1RM increased similarly for both conditions (warm: 25±11%; cool 26±11%; time: p<0.001; condition: p=0.891). Trivial changes were observed in arm composition. Cool training attenuated increases in peak twitch amplitude, when assessed in a normothermic state in temperate conditions (warm: 38±26%; cool 2±7%; time: p=0.011; condition: p=0.016).
Conclusion: All three regimes of resistance exercise increased biceps brachii temperature substantially and for a prolonged period. Immersion cooling effectively prevented any such increase. Preventing exercise-induced elevation in muscle temperature did not attenuate functional or structural adaptations to strength training, thereby indicating that muscle temperature lacks a role or is redundant in strength adaptations, although this remains to be determined in a larger population
Polarization Gradient Cooling in a Far Off-Resonant Dipole Trap
No full textWe present here a novel framework within which the implementation of sub-Doppler cooling, in prevalent form manifest as polarisation gradient cooling, on atomic systems subsistent in both a free-space regime and one in the presence of a deep, far-off resonant dipole trap, can be fundamentally understood. We develop first a theoretical means through which the predicted presence or absence of atomic cooling, for an arbitrary frequency of an incident cooling field, on the D2 line of Rb-85 can be made. Following such a development, the framework itself is applied to both free-space atomic systems and those under which the imposition of a dipole potential is physically realised, in the pursuit of making transparent the mechanisms governing the integration of polarisation gradient cooling in a diverse array of systems. Excellent agreement is evinced between theory and experiment in all atomic systems investigated, suggesting that the theoretical framework developed provides an adequate description regarding the mechanisms of polarisation gradient cooling pertinent to its implementation on the D2 line of Rb-8
The use of metformin in patients with renal impairment
No full textMetformin, a biguanide, is widely accepted to be the preferred first-line oral antihyperglycaemic agent to manage type 2 diabetes. There is considerable concern that patients receiving metformin therapy may be at an increased risk of developing lactic acidosis. The risk has traditionally been assumed to be increased in patients with chronic renal impairment, resulting in many patients being denied access to an effective first-line treatment agent. The overarching aims of this thesis were to explore the safe use of metformin and to create a renal dosing guideline that will mitigate the risk of lactic acidosis.
The safe use of metformin was explored by formally evaluating the association between metformin therapy and lactic acidosis in published case reports of metformin associated lactic acidosis (MALA) using two causality assessments. Metformin was found to play only a possible role in the development of lactic acidosis based on the results from the causality assessments. Almost all cases presented with other risk factors that could on their own have caused lactic acidosis.
A subgroup analysis was performed in MALA cases with a history of chronic renal impairment to explore the relationship between metformin dose, plasma concentration and lactic acidosis. Most cases presented with acute renal failure, confounding the relationship between metformin dose and plasma concentrations. The prescribed metformin dose exceeded the dosing recommendations in over 60% of cases with an estimated glomerular filtration rate of <60 mL/min by a median of 1000 mg/day. Despite this, based on simulations, the pre-admission plasma metformin concentrations measured pre-dose did not exceed the proposed upper limit of the therapeutic range of 5 mg/L.
A quantitative analysis was performed to explore the relationship between plasma metformin and lactate concentrations. Plasma metformin concentrations greater than 4.5 mg/L were found to be associated with severe hyperlactatemia. These findings suggest that metformin doses should be adjusted to maintain plasma concentrations below 4.5 mg/L to mitigate the risk of lactic acidosis.
A noncompartmental pharmacokinetic analysis was performed to explore the pharmacokinetics of metformin in renal impairment, from which an empirical renal dosing guideline for metformin was developed. Patients with poorer renal function were found to have lower apparent and renal clearance for metformin. These findings support the notion that metformin can be used safely for the treatment of type 2 diabetes mellitus in patients with chronic renal impairment provided plasma metformin concentrations are maintained within a safe therapeutic range.
A population pharmacokinetic model for metformin was developed and evaluated. A covariate analysis found that renal function and total body weight could describe patient variability in the apparent clearance and central compartment volume for metformin, respectively. The developed population pharmacokinetic model was used to assess the safety of the empirical renal dosing guidelines and the current published renal dosing guidelines in the New Zealand Formulary. Based on the simulations, plasma metformin concentrations are not expected to exceed the upper limit of safety of 4.5 mg/L under either of the dosing guidelines.
The influence of flip-flop pharmacokinetics in population pharmacokinetic models was explored using metformin as a motivating example. Approaches to address problems arising due to flip-flop in population pharmacokinetic models are presented in this thesis.
In conclusion, the findings in this thesis support the notion that metformin can be used safely for the treatment of type 2 diabetes mellitus provided plasma metformin concentrations are maintained within a safe range. In addition, an empirical renal dosing equation for metformin was developed and assessed for safety
Elucidating the Relationship between Borderline Personality Disorder and Intimate Partner Violence
No full textThis was the first research project to examine the established Borderline Personality Disorder (BPD) and Intimate Partner Violence (IPV) relationship comparing the DSM-5 traditional categorical personality disorder (PD) model with the DSM-5 Alternative Model of Personality Disorder (AMPD). The AMPD is meant to address several limitations of the traditional PD system, and is consistent with how most PD experts considers PDs to be best conceptualised. The specific BPD-relevant AMPD personality traits that influence the BPD-IPV association were also examined, in addition to the associations between BPD symptomology, IPV intervention programme outcomes and recidivism. Study 1 used a sample of 250 community-dwelling men and women recruited through an established crowdsourcing platform, and Study 2 was based on archival data of 531 men who took part in a court-ordered IPV intervention programme. Across both studies, the results showed that both traditional and AMPD BPD operationalisations were approximately equally associated with IPV perpetration, although traditional BPD demonstrated some advantages in regards to psychological IPV. Study 1 indicated that the AMPD trait facets of hostility (negative affectivity), suspiciousness (negative affectivity), and risk-taking (disinhibition) were most strongly associated with IPV perpetration for the total sample, and additional negative affectivity trait facets were also associated with IPV for men only. Study 2 findings showed that the AMPD disinhibition domain was most strongly associated with IPV perpetration, though negative affectivity conferred a meaningful association as well. Study 2 further indicated that IPV offenders with BPD symptomology were at increased risk of failing to complete IPV treatment, and to re-offend in a one year follow up period. Implications for these findings across studies are discussed
Diversity and inclusion in sport organizations. A subversive functionalist approach
No full textThe concepts of diversity and inclusion (D&I) as managerial values have become an integral part of most institutional policies, and sport organizations are no exception. Yet, notwithstanding their common usage in public and organizational discourse, there is no consensus on what D&I actually mean, nor about what their main dimensions are and how to manage them. The aim of my thesis is thus to better understand why sport organizations engage in D&I initiatives, how this commitment is translated into practice, what challenges they encounter, and what organizational practices may facilitate moving forward. In doing this, I propose a subversive functionalist approach informed by mainstream and critical management studies in order to produce theoretical and practical insights towards progressive change. In particular, I explore the potential of this construct in a case study of New Zealand Rugby and its public commitment towards greater D&I. Data were collected from 18 one-on-one interviews with executives and managers, analysis of relevant documents, and fieldnotes. Findings reveal that the way in which D&I efforts are rationalized is highly context specific and varies across, and within, organizations. The study also illustrates that creating and sustaining change, particularly related to D&I, is a complex, dynamic, and often “messy” undertaking. Nevertheless, findings suggest that mainstream organizational change models can effectively assist, in tandem with critical management studies, in advancing social change. Thus, this research encourages more sport management scholars to consider conducting their work from a subversive functionalist perspective, as it can provide a way forward to how the field seeks to transform sport management as it is practised, studied, and taught
Trophic structure through the history of exploitation in New Zealand fish communities
No full textMarine ecosystems have been under a considerable amount of stress due to human activities, especially after industrialization. The abundance and ecological interactions of exploited fishes are influenced by fishing activities, climate change, and natural environmental variability, but there is a lack of knowledge on how these community parameters have changed over time. In the present study, temporal shifts in the trophic structure and composition of an important commercial fish community along the east coast of the South Island of New Zealand was investigated. The Marine Trophic Index (MTI) and species composition of the reported commercial fisheries landings for the whole country were used to identify periods of fisheries expansion and shifts in the trophic architecture of the landings. A stable isotope approach was used to estimate resource use and trophic level of fishes, comparing these parameters spatially and temporally. It was demonstrated that it is possible to access carbon and nitrogen stable isotope values from preserved fishes, for both bulk tissues and specific amino acids, which enabled this work to access ecological information from specimens stored in museum samples. The results demonstrate that fisheries industrialization occurred between 1970 and 2000 in New Zealand, increasing MTI values and shifting the relative landings composition from inshore to offshore and deep-water species over time. Regional comparisons demonstrated that modern fish communities from Otago relied more heavily on macroalgae production when compared to those from Kaikoura, linked to higher fishery yields in the former. When analyzing the same parameters from museum specimens collected before the full expansion of industrialized fisheries, modern species inhabiting the outer shelf and slope also showed a reduced reliance on macroalgae production, together with an increased trophic level. When considering continuous changes in the trophic parameters, environmental factors and prey abundance had a significant relationship with the variation of trophic parameters for most fish assemblages. Trophic parameters of the inner shelf assemblage also showed a relationship with MTI throughout time, indicating the earlier effects of coastal fisheries. Although Kaikoura and modern communities showed a wider niche breadth compared to Otago and historical samples, respectively, tarakihi was the only species to show both regional and temporal trends. Tarakihi stocks in the region have been overexploited and are sensitive to habitat degradation, which could be linked to the shift in trophic structure observed here. Furthermore, temporal changes in community composition towards a relatively higher abundance of lower trophic level species were observed from the analysis of long-term trawl survey data. Species with decreasing abundance that presented shifts in trophic parameters with time, such as red cod, had their trophic level and resource use occupied by species with increasing abundance, like spiny dogfish. The present study demonstrates how the trophic structure and composition of important commercial communities have changed over time and how they are related to natural and anthropogenic effects, with the potential to alter regional fishery yields. This study highlights how uncovering ecological baselines before human impacts is an important step towards the implementation of an ecosystem-based management approach to fisheries resources
Using hybridization chain reaction to investigate the homology of gene regulatory networks
No full textHow gene regulatory networks (GRNs) help produce phenotypic variation is a central question in developmental biology. A particularly well-studied class of GRNs are those performing segmentation: the subdivision of a developing organism’s body axis into repeating units. Segmentation can proceed either simultaneously, where every body segment is laid down at the same time, or sequentially, where new body segments are added one by one at the posterior of the embryo. A recent model proposes that both these modes of segmentation can be explained using one, multifunctional, GRN, the topology of which is derived from the pair rule system of the vinegar fly Drosophila melanogaster (which segments simultaneously). This GRN can be subdivided into two, modular, networks, the first of which establishes the initial pair rule prepattern, and the second of which converts this pattern into the segment polarity output. Which of these networks is active in a given tissue is controlled by the timer genes caudal, Dicheate, and odd-paired.
I use Nasonia vitripennis to investigate how this multifunctional segmentation GRN can produce different types of segmentation. Nasonia are scientifically interesting because they combine multiple methods of segmentation, so provide an ideal system to investigate how GRNs produce multiple phenotypes. In the anterior, Nasonia perform progressive segmentation: temporal segment specification along the anterior-posterior axis, from a pair-rule prepattern. In the posterior, they undergo sequential segmentation. I investigated the conservation of the Nasonia GRN using HCR, a method to visualize gene expression within whole, fixed tissue. I used tools from philosophy of science (the notion of activity-function, or function that does not describe how a trait is used) to argue that modelling can be used to define the intrinsic function of a GRN. These intrinsic functions can then be used as a definition of GRN homology. I then used these concepts to argue that the early network of Nasonia is homologous to that of Drosophila, but that the structure of the late network is not conserved. Because most of the unique segmentation dynamics in Nasonia occur during the early network, my data is unable to explain these unique dynamics using GRN topology alone. On the other hand, providing the Drosophila GRN model with the Nasonia timer gene expression patterns was able to produce Nasonia’s progressive segmentation. This demonstrates two things. Firstly, changes to GRN topology cannot explain Nasonia’s progressive segmentation, but dynamic modelling of GRNs can. This fits with previous work showing that a GRN structure is not a biological explanation, and that GRNs can exhibit different behaviours from the same topology. Secondly, I showed that progressive segmentation is an intermediate between simultaneous and sequential segmentation. Sequential and simultaneous segmentation are therefore a continuum, not a binary, and a remarkable variety of phenotypes could be produced by simply varying expression of the timer genes
Consumers' informed decision-making in response to direct to consumer advertising of prescription medicines
No full textDirect-to-consumer advertising of prescription medicines (DTCA), a disputed health communication strategy, has been legally developed only in New Zealand and the United States. DTCA has raised significant concerns in New Zealand, especially because it is self-regulated by the industry, which currently does not prevent it from offering incomplete and misleading information. Even in the United States, where DTCA is regulated and overseen by the Food and Drug Administration, violations by pharmaceutical companies are widespread and predominantly involve deceptive information. Given that regulation of DTCA has not been effective, the main purpose of this research was to explore how consumers respond to DTCA and whether DTCA is socially responsible. More specifically, this research aimed to examine the factors linking to individuals’ behavioural responses to DTCA, reveal the issues affecting consumers’ informed decision-making, conceptualise the characteristics of vulnerable consumers with regard to DTCA, and finally develop an ethical framework for DTCA based on the Corporate Social Responsibility model. To achieve this goal, this research comprised three studies.
Study one, built on communication inequality and the Structural Influence Model of health communication, identified factors associated with consumers’ self-reported behavioural responses to DTCA. By analysing survey data collected from a nationally representative sample of adults (n=2057), this study found that drug advertising was more likely to influence ‘at-risk’ individuals (i.e., lower-income, poorer health status, older, less educated, and ethnic minorities), and those who had more positive attitudes toward DTCA, who were more materialistic and who rely on the internet for medical information. These individuals, therefore, may be more vulnerable to drug advertising and may make poorly informed decisions accordingly. The findings raise major concerns regarding the ethicality of medicine advertising and highlight the requirement for stricter regulations to ensure that medicine advertisements offered by pharmaceutical firms are ethical. Preliminary findings from this study were presented at the EMAC Conference, 2016 and developed into a journal paper that was published in the BMJ Open in 2017.
Study two, based on the same sample as study one, extended study one and examined the link between healthy/unhealthy lifestyle habits and individuals’ responses to DTCA. This study revealed that individuals with unhealthier lifestyles were more likely to respond to DTCA and thus might be more vulnerable to DTCA. The link between unhealthy lifestyle behaviours and being influenced by drug advertising raises concerns about the misuse or overuse of medicines for health problems that may be solved with a healthier lifestyle. Individuals with risky lifestyle behaviours should be fully informed to be able to make appropriate health decisions. These findings were published in the Australian & New Zealand Journal of Public Health in 2019. Collectively, the outcomes from study one and study two informed the design of study three.
Study three focused on social responsibility, and more specifically ethicality, in DTCA in New Zealand. The study involved 29 in-depth interviews with health professionals to explore their thoughts and recommendations regarding the advertising of prescription medicines. The findings revealed that most informants had concerns regarding consumers’ autonomy in decision-making, their ability to understand/interpret the information presented, and their ability to make informed decisions. According to informants’ perspectives and experiences, consumers’ capability, self-efficacy and other characteristics could play an essential role in their fully informed decision-making. The health professionals thought that although most consumers are vulnerable to DTCA and are not able to make informed decisions, there are specific consumers who are even more vulnerable to DTCA. The unethical nature of DTCA was underlined. Of importance, the thematic analysis of informants’ opinions showed the existence of persuasion and opportunism in DTCA, which informants thought consumers would generally not be able to detect. From the findings, a framework of criteria for socially responsible DTCA was proposed to help individuals make informed decisions and improve their well-being. Recommendations pertained to the content of DTCA, types of advertising channels employed, types of advertised medications, social responsibility/ethicality of DTCA providers, as well as stricter regulations and supervision of DTCA. The research outcomes have important implications for the regulation of DTCA. The findings could also help pharmaceutical advertisers to fulfil the consumers’ right to be informed and to choose. The principal theoretical implications of this study were that the findings provided new perspectives for conceptualising socially responsible DTCA, informed decision-making and vulnerable consumers in the DTCA context. Initial findings from study three were presented at the Macromarketing Conference, 2017.
Taken together, the three studies showed that consumers, especially those who are at risk, are more likely to be influenced by DTCA and may not be able to make fully informed decisions. Moreover, findings revealed that DTCA is not socially responsible in its current form, and changes need to be made to help consumers’ informed decision-making. Recommendations drawn from the three studies, to improve the regulation and ethicality of DTCA, are presented in the concluding discussion and helped to inform a submission to the Therapeutic Products Bill, 2019
Laborastories: Creative Assessment for NCEA Science
No full textThe National Certificate of Educational Achievement (NCEA) is the main form of assessment used in New Zealand secondary schools. This system promotes fragmentation of knowledge and does not align with the values of the New Zealand Curriculum, (NZC) that learning should not be confined by subject boundaries. There is evidence to suggest that integration of subject areas can improve NCEA achievement for students, and that use of stories in school science courses can enhance engagement. The aim of this research was to find out if science teachers are interested in using storytelling as a vehicle for learners to present their understanding in NCEA science courses, and what professional development is needed to help them do this. A mixed methods approach was employed, consisting of an online questionnaire distributed to NCEA science teachers in New Zealand and 13 semi-structured interviews with individual science teachers. I found that there is interest amongst the teaching community in storytelling for creative assessment but there are significant barriers to this, most commonly: unwillingness of other people, time constraints, and increased workload for both teachers and students. Teachers with previous experience in creative and/or cross-curricular assessment methods were more open to using storytelling techniques and less negatively impacted by potential barriers to these methods. Teachers identified collaboration with other teachers, ready-made resources, and time as their most pressing needs for implementation of creative assessment methods. These findings were used to inform the creative project of this thesis: two podcasting workshops for teachers and a website, www.laborastories.nz, providing resources, opportunities for collaboration, and advice for teachers interested in using storytelling for creative NCEA science assessment