12,112 results for Doctoral

  • Rural parents’ engagement in education in Bangladesh: problems and possibilities

    Hasnat, Mahammad Abul (2017)

    Doctoral thesis
    University of Canterbury Library

    This thesis explores the engagement practices, understandings and experiences of parents and teachers in the rural context in Bangladesh. It investigates the underlying factors that create blocks to engagement. It examines the complex interplay of expectations, blame-giving, financial constraints and pervasive social problems within the context, and how that interplay both calls for and yet inhibits engagement. The thesis also reports one head teacher’s initiatives to overcome the blocks and to create space for engagement. The study is a qualitative case study that utilises an emergent research design. This process of data collection offered me the flexibility to respond to contextual conditions and to capture rich data through group discussions and individual conversations with the teachers, parents and the community people. It allowed me to observe participants’ activities, review related documents and maintain a reflective research journal. The importance of place is highlighted throughout as my study sought to identify and report not only actual practices but the cultural, social and economic conditions that shape those practices. Place contextualises where policy decisions are to be implemented. Place is also a significant consideration in identifying the kinds of steps that might be taken to overcome barriers. Therefore, attention is given to describing the rural context of Bangladesh and its people in some detail. The study begins with examining the reasons for importance being placed on parental engagement by policy, and reports the problems in implementing policy aspirations in the rural context through the lenses of parents and teachers. It found that teachers were frustrated by lack of parental response to invitations and by their apparent disinterest in their children’s educational progress. It also found that parental illiteracy and poverty were major factors in preventing parents from becoming engaged with educational matters. Additional factors were unsatisfactory communication processes, the complex nature of the cultural relationship between parents and teachers, and the politicised nature of schools’ public programmes. I found of understandings, by both parents and teachers of the concept and possibilities of engagement were largely very limited. The thesis explores how cultural and socio-economic conditions shape dominant discourses and arbitrate access to cultural capital as well as posing practical problems. These factors impede parental engagement in education and are powerful indicators of why such engagement is needed. Next the study reports the activities of one head teacher who is taking a different approach in the same context. It details his different and innovative strategies for reaching out to parents and creating space for them to be become involved with their children’s learning and with the school. It also identifies a number of key characteristics of his leadership that allow him to make a difference and suggests that these characteristics are ones that should be looked for and fostered in appointment processes, professional development and official support. Finally the implications for policy and practice of the findings are discussed. Two models are offered: the first of the nature and possibilities of parental engagement in rural contexts of Bangladesh; the second of the processes needed to develop parental engagement in such contexts. The study is a deliberately contextual one. However, some of the contextual factors may have resonances with other contexts and other countries. Moreover the analysis of how contextual factors impact on parental engagement may also be relevant to other contexts. Therefore while the focus in on parental engagement in rural contexts in Bangladesh, it is envisaged that the study will also have wider relevance.

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  • An investigation into the use of applications on personally owned devices to enhance student engagement in large lectures

    Nesbit, Trevor Richard (2017)

    Doctoral thesis
    University of Canterbury Library

    Increasing student numbers and reduced government funding have seen a trend towards there being larger numbers of students in lectures, with this having an impact on the extent of student interaction, participation, and engagement in lectures in many institutions. The impetus for this research came from a desire to retain much of the interaction, participation, and engagement that takes place in smaller classes when changing from small lectures to lectures with more than 100 students. A pilot study demonstrated that the use of applications on personally owned devices (APODs) in the form of a text messaging based system or an application running on a smart phone could create a marked increase in student interaction, participation, and engagement. This was followed by a more formal investigation using a pragmatic paradigm and a mixed methods research approach that was consistent with design-based research. This included interviews of lecturers and learning advisers, student surveys and student focus groups. The findings conclude that the use of APODs during lectures has the potential to increase student interaction. The participation and engagement through the creation of a two-way feedback channel between lecturers and students, allows for student misconceptions to be identified and addressed in a manner that can make learning more enjoyable, authentic and effective. This potential benefit can be realised by addressing the pedagogical and technological issues involved in the use of APODs in lectures. The main contributions of this research are the models that have been developed surrounding how to use APODs in a pedagogically sound manner; the importance of designing effective activities when APODs are being used; how to use APODs to cater for different groups of students; the benefits of using APODs; and how to address the challenges of using APODs. Implications for further research are also identified.

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  • Predictors of Punjabi, Hindi and English reading comprehension among multilingual children in the Punjab Region of India

    Gautam, Seema (2017)

    Doctoral thesis
    University of Canterbury Library

    The research reported in this thesis investigated cognitive-linguistic predictors of reading comprehension (both within and across languages) among multilingual primary school children in the Punjab region of India. The participants of this study learn three languages: Punjabi, Hindi and English; and are exposed to all three from the initial stage of literacy acquisition. Unlike English, the Punjabi and Hindi orthographies are written nonlinearly with a horizontal bar on the top of the aksharas that connects aksharas within a word, and include vowel symbols that have independent and dependent forms. Both Punjabi and Hindi are alphasyllabic orthographies, whereas English is an alphabetic orthography. Over 400 trilingual school children in Punjab (India) from grades 2 to 5 completed a measure of text reading comprehension that comprised passages followed by questions about details in those passages. Reading comprehension levels were compared to the measures of listening comprehension, phonological processing, orthographic knowledge and speed of processing. Analyses indicated the Punjabi, Hindi and English reading comprehension levels were predicted by measure of listening comprehension and word decoding, with the latter being predicted by phonological and orthographic skills. Such findings were consistent with current models of reading derived from studies of English. However, in contrast to these models, measures of orthographic skills were also predictive of variance in reading comprehension independent of word decoding across Punjabi, Hindi and English models. Contributions of phonological processing and speed of processing were also observed in the English reading comprehension model, again independent of word decoding processes. Overall, Punjabi and Hindi reading comprehension was predicted by similar predictors, with English reading comprehension showing more variations in predictors. Further analyses investigated the influence of Punjabi and Hindi cognitive-linguistic skills on English reading levels. The findings indicated that, in the younger cohorts of students who are more likely to have less reading experience, the influence of Punjabi and Hindi measures on English was limited to word recognition. However, once these multilingual children acquire more expertise in decoding skills (i.e., in the older cohort), listening comprehension, orthographic knowledge and phonological processing in Punjabi and Hindi influenced levels in English reading comprehension. The overall findings from this thesis were used to derive three multilingual models of Punjabi, Hindi and English and one cross-linguistic model of English reading comprehension. These models suggest that a simple view of reading could be applied to Punjabi and Hindi orthographies in a similar way to English. However, additional influences of orthographic knowledge for all three languages (Punjabi, Hindi and English) in such multi-literate learners will need to be taken into account. Additionally, the influence of first and second language skills will need to be considered when developing models of third language reading comprehension. The proposed four models that includes the additional factors are discussed in light of previous research and theories/models in the field.

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  • A spatio-temporal approach for exploring human-wildlife conflict using the kea (Nestor notabilis) as a case study

    Kennedy, Erin (2017)

    Doctoral thesis
    The University of Auckland Library

    Globally, human-wildlife conflict is one of the main threats to the continued persistence of numerous species. In my thesis, I developed a spatio-temporal framework with the aim that it inform management of conflict-prone animal species such as the kea (Nestor notabilis). My specific research aims were to: 1.) characterise the movement and behavioural patterns of kea; 2.) quantify the nature and extent of kea interactions with anthropogenic infrastructure in their environment; 3.) explore how human activity may be affecting kea behavioural patterns; and 4.) assess the impact of human-wildlife conflict on kea population dynamics relative to other important threats. Applying a spatial framework to explore human-wildlife conflict requires the collection of spatio-temporal data to describe movement patterns and their relation to human features in the landscape. First, I assessed the use of animal-borne GPS telemetry as a means of collecting movement data from kea. I observed: no apparent adverse effect of the loggers on the condition of the kea; no damage to the devices that impaired their function; and that the operational performance provided high-resolution data sufficient characterising the movement patterns of wild kea. The high proportion of GPS fixes recorded in human areas and strength of habitat preference revealed that the kea in my study were attracted to human areas. Using a switching Monte-Carlo Markov-Chain model I was able to assign behavioural states to the GPS fixes, revealing that kea spent significantly more time on ground-based behaviours than flight. Kea demonstrated strong temporal variation in proximity to humans areas, and generally were in/or close to human areas at times of the day when human activity was highest. My results showed that individual kea clearly differ substantially in their movement patterns; most probably because of differences in age or reproductive status. Temporal variation in patterns of behaviour indicated that, for some individuals, durations of area-restricted behaviour varied as a function of proximity to human areas. The outcomes of a stochastic stage-based model used in a population viability analysis indicate that the biggest threat to kea populations is predation by introduced mammals, but as human populations continue to grow in kea habitats humaninduced mortality could become a major threat in the future. My results suggest the spatial approach adopted here is an effective means of describing fundamental aspects of humanwildlife interactions and potential conflict. As technology and the associated analytical toolkit continue to improve, I believe the use of spatio-temporal approach will prove to be a vital tool for exploring and mitigating human-wildlife conflict in a range of species.

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  • Novel grafting materials for sinus floor elevation in the sheep model

    Sheftel, Yevgeny (2017)

    Doctoral thesis
    University of Otago

    Introduction: Sinus floor elevation (SFE) may be required for implant placement in the severely resorbed posterior maxilla. Although often successful, autologous bone grafting requires a donor site and may lose substantial volume while remodelling. Bone replacement grafting (BRG) materials were developed to overcome these limitations. This study investigated three novel grafting materials: 1) equine collagen cone (CN), 2) equine collagen cone filled with biphasic calcium phosphate particles (CO), 3) deproteinized bovine bone particles coated with polylactic acid and poly ε -caprolactone copolymer (SB). These were compared with the most commonly-used bovine bone BRG, Geistlich Bio-Oss® (BO). Methods: The extra-oral access sinus grafting model from Haas et al. (1998) was used in 11 cross-bred female sheep. Two experimental sites on each side of the animal were prepared. CN, CO, SB, BO were each placed through separate 10 mm access window in the antral wall, under the elevated Schneiderian membrane. BO sites were covered with a porcine collagen membrane (Geistlich Bio-Gide®), while for CO, SB, BO sites the equine collagen membrane (RESORBA PARASORB®) from the manufacturer of these experimental materials was used. The animals were euthanised after 16 weeks. New bone, residual graft particles and connective tissue areas were measured on un-demineralised resin-embedded sections. Results: One sheep did not survive the surgery. All sites in remaining ten sheep healed uneventfully. The CN and SB grafting materials resorbed completely and failed to form new bone. BO and CO particles were bridged by the new bone, the new bone fraction was 10% (±9%) for BO and 4% (±5%) for CO. The differences were not statistically significant. Conclusions: CN and SB cannot be recommended for sinus grafting, based on this model. BO and CO demonstrated comparable histologic and histomorphometric outcomes.

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  • Intelligent condition assessment of power transformers

    Peimankar, Abdolrahman (2017)

    Doctoral thesis
    University of Canterbury Library

    This thesis begins by providing an introduction to different transformer failures and the most effective condition monitoring techniques. Different failures are introduced and their corresponding fault diagnosis methods are listed to have a better understanding of failure modes and their consequence effects. An investigation into monitoring major failures of transformers using dissolved gas analysis is then presented. Various conventional, dissolved gas analysis based, fault diagnosis techniques are presented and the drawbacks of these methods are discussed. Intelligent fault diagnosis methods are introduced to overcome the problems of the conventional techniques. An overview of statistical and machine learning algorithms applied in this research is also described. Preliminary research results on transformer load tap changers fault classification are reported. A hierarchical fault diagnosis algorithm for transformer load tap changers using support vector machines is used, in which, for each fault class, a unique single support vector machine algorithm is employed. However, while the developed algorithm is reasonably accurate, the shortcomings of applying single learning algorithms are discussed and a proposal for developing a more robust and generalised transformers condition assessment algorithm is made. An intelligent power transformer fault diagnosis algorithm is then developed to classify faults of transformers. The proposed fault diagnosis algorithm is an ensemble-based approach which uses different statistical and machine learning algorithms. In the first phase of the proposed algorithm the most relevant features (dissolved gases) corresponding to each fault class are first determined. Then, selected features are used to classify transformer faults. The results of this algorithm show a significant improvement, in terms of classification. A time-series forecasting algorithm is developed to predict future values of dissolved gases in transformers. The dataset for this algorithm was collected from a transformer for a period of six months which consisted of seven dissolved gases, a loading history, and three measured, ambient, oil, and winding, temperatures of transformer. The correlation coefficients between these 11 time series are then calculated and a nonlinear principle component analysis is used to extract an effective time series from highly correlated variables. The proposed multi-objective evolutionary time series forecasting algorithm selects the most accurate and diverse group of forecasting methods among various implemented time series forecasting algorithms. The proposed method is also compared with other conventional time series forecasting algorithms and the results show the improvements over the different forecasting horizons.

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  • Genetic factors associated with orthodontic pain in children and adolescents: a pilot study

    Sew Hoy, William Hugh (2017)

    Doctoral thesis
    University of Otago

    Introduction: Pain is often reported as being the worst aspect of orthodontic treatment. Nearly all patients experience pain and discomfort at their teeth at some point during orthodontic treatment. Little information exists on the severity of pain in the latter stages of orthodontic treatment. In addition, no studies have investigated the role of genetic factors on pain caused by fixed appliances. Objectives: To investigate whether demographic, clinical or genetic factors are associated with the severity of pain experienced following adjustment of fixed orthodontic appliances. Methods: Eighty-two participants undergoing fixed orthodontic treatment were recruited. Baseline DNA was collected via blood or saliva samples. Immediately after bond-up or an adjustment of the fixed appliances, the participants used a smartphone app to record regular pain scores at their teeth over the following three days. Results: Pain peaked approximately 19 hours after the orthodontic adjustment, then gradually returned toward baseline levels by day three. Pain on chewing was significantly greater than the resting pain at the teeth at all time points concerned. There was a significant difference in the total amount of pain at the teeth over the three days when comparing bond-ups to no arch wire changes (with or without bends placed). Gender, age, and time in treatment were not associated with the severity of pain experienced after an orthodontic adjustment. The rs931233 SNP of the HTR2A and the rs4646310 SNP of the COMT genes were significantly associated with pain severity. Haplotypes of the COMT gene also showed promising, although non-significant associations with pain severity. Conclusions: Pain on chewing is significantly more painful compared to resting pain at the teeth after adjustment of fixed appliances. SNPs of the HTR2A and COMT gene were associated with the severity of pain following adjustment of fixed appliances. Therefore, it seems that genetic factors have a modifying effect on orthodontic pain (as is the case with many other pain conditions such as TMD, fibromyalgia, and experimental pain). Larger samples are required to investigate these associations further.

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  • Expression of the lysyl oxidase family in odontogenic lesions

    Abdul Rahman, Nawal Radhiah (2017)

    Doctoral thesis
    University of Otago

    Background: The lysyl oxidase family of enzymes consists of five members, namely lysyl oxidase (LOX) and lysyl oxidase-like (LOXL) 1-4. They are secreted enzymes whose function is to stabilise the extracellular matrix via crosslinking collagens and elastins. The enzymes are mostly known for their extracellular function but little is known about their intracellular function. Few studies have investigated LOX expression in the oral and maxillofacial region and those that exist are largely concerned with oral submucous fibrosis and oral squamous cell carcinoma. With regard to odontogenic lesions one study exists which showed increased expression of LOXL4 in the stromal tissue of odontogenic keratocyst (OKC). Objective: To determine the expression of LOX family proteins and genes in locally aggressive odontogenic lesions (ameloblastoma and OKC) in comparison with non-aggressive odontogenic lesions (dentigerous cyst (DC) and hyperplastic dental follicle (DF)) using immunohistochemistry (IHC) and quantitative reverse transcriptase real-time polymerase chain reaction (qRT2-PCR). Method: For IHC, formalin-fixed paraffin-embedded (FFPE) tissue samples of ameloblastoma (n = 10), OKC (n = 15), DC (n = 6) and DF (n = 9) were used with antibodies against LOX and LOXL1-4. Positive and negative controls were used for validation. Qualitative assessment of the pattern and distribution of staining was undertaken at varying magnifications. Automated quantitative assessment of digitised IHC images was performed using Fiji Software (Image J 1.51K). Specifically, the extent of positive reaction and intensity of staining were examined in three representative areas of the epithelium and connective tissue in each specimen at 400x magnification. One way ANOVA tests were performed using GraphPad Prism software (La Jolla California USA), and P values of 2 and p<0.05 for each analysis. Result: The LOX family proteins and genes showed differential patterns of expression in each lesion examined. Significant reduction of LOXL3 was observed in ameloblastoma at both protein and gene levels. LOXL4 protein was overexpressed in the epithelium, but underexpressed in the connective tissue of ameloblastoma and OKC. The expression of LOX family genes and proteins in DC showed a significant variation compared with ameloblastoma and OKC, whereas the protein expression patterns were similar between ameloblastoma and DF. Conclusion: 1) LOX family expression was different in ‘aggressive’ odontogenic lesions compared with ‘non-aggressive’ odontogenic lesions, dentigerous cyst in particular. 2) Variable LOX family expression between ameloblastoma and OKC may reflect their pathogenesis and biological behaviour. 3) The similarities of LOX family expression observed in ameloblastoma and hyperplastic dental follicle may reflect the embryonic dedifferentiation of ameloblastoma. 4) Dentigerous cyst serves as a proper ‘control’ tissue as opposed to hyperplastic dental follicle with regard to study of the LOX family.

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  • Planning for resilient communities: and every other day: learning from the Canterbury 2010-2012 earthquake sequence

    Banwell, Karen (2017)

    Doctoral thesis
    University of Canterbury Library

    After a disaster, cities experience profound social and environmental upheaval. Current research on disasters describes this social disruption along with collective community action to provide support. Pre-existing social capital is recognised as fundamental to this observed support. This research examines the relationship between sense of place for neighbourhood, social connectedness and resilience. Canterbury residents experienced considerable and continued disruption following a large and protracted sequence of earthquakes starting in September 2010. A major aftershock on 22 February 2011 caused significant loss of life, destruction of buildings and infrastructure. Following this earthquake some suburbs of Christchurch showed strong collective action. This research examines the features of the built environment that helped to form this cooperative support. Data were collected through semi-structured interviews with 20 key informants followed by 38 participants from four case study suburbs. The objectives were to describe the community response of suburbs, to identify the key features of the built environment and the role of social infrastructure in fostering social connectedness. The last objective was to contribute to future planning for community resilience. The findings from this research indicated that social capital and community competence are significant resources to be called upon after a disaster. Features of the local environment facilitated the formation of neighbourhood connections that enabled participants to cope, manage and to collectively solve problems. These features also strengthened a sense of belonging and attachment to the home territory. Propinquity was important; the bumping and gathering places such as schools, small local shops and parks provided the common ground for meaningful pre-existing local interaction. Well-defined geography, intimate street typology, access to quality natural space and social infrastructure helped to build the local social connections and develop a sense of place. Resourceful individuals and groups were also a factor, and many are drawn to live near the inner city or more natural places. The features are the same well understood attributes that contribute to health and wellbeing. The policy and planning framework needs to consider broader social outcomes, including resilience in new and existing urban developments. The socio-political structures that provide access to secure and stable housing and local education should also be recognised and incorporated into local planning for resilience and the everyday.

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  • Respiratory mechanics and patient effort in mechanical ventilation

    Redmond, Daniel Paul (2017)

    Doctoral thesis
    University of Canterbury Library

    Positive pressure mechanical ventilation is a crucial therapy for patients with respiratory failure in the intensive care unit. The progression of disease and condition of the lung both influence mechanical behaviour of the respiratory system. Guiding mechanical ventilation treatment with respiratory mechanics allows a patient-specific approach to treatment, which can lead to improved alveolar recruitment, less ventilator induced lung injury and improved patient outcomes. Mathematical models of respiratory mechanics that can integrate this data into real-time, patient-specific respiratory mechanics parameters to monitor and guide treatment. Thus mathematical models can play an increasingly necessary role in implementing patient-specific mechanical ventilation therapy. This research tests and optimises respiratory mechanics models across a range of clinical data, predominantly from the pilot phase of the Clinical Utilisation of Respiratory Elastance (CURE) trials. A key issues in any such models is the trade-off of elastance and resistance, where poor models of resistance skew the results and utility of elastance and estimate and make the model unusable. This research presents a model that allows resistance to vary linearly with pressure. It offers similar performance to a more complex viscoelastic model in increasingly common pressure support modes, and improvements in volume control modes of ventilation. The variable resistance model suggests that resistance increases with pressure during inspiration. Existing models for respiratory mechanics do not perform well in the presence of patient effort. However, patient effort is increasingly common in the increasingly preferred ventilation support modes. Patient effort can be measured, but adds significant invasiveness and cost, and this is not clinically feasible. This research explores the impact of patient effort on respiratory mechanics, and how to maintain stable and accurate estimations of respiratory mechanics when patient effort is unknown, variable in time and effort, and significantly affects identified model results. A pressure reconstruction algorithm, and a polynomial model of patient effort are developed to allow stable estimations of respiratory mechanics in the presence of patient effort. A comparison of five different models and reconstruction methods tests their ability to provide consistent and correct estimates of respiratory mechanics in different volume control datasets with and without patient effort. An iterative pressure reconstruction method combined with stacking of small groups of reconstructed breaths in moving windows is shown to be the best method for consistent and accurate respiratory mechanics estimation. Methods are also presented for automated asynchrony detection, and while they achieve promising results, there is need for more accuracy before they are clinically useful. In particular it is difficult for automated methods of monitoring asynchronous patient effort to be highly accurate, and there is a need for a broader set of patient data to further develop any such methods. Overall, this thesis evaluates the ability of mathematical models to assess respiratory mechanics for monitoring and clinical decision support in mechanical ventilation, and especially addresses this issue in the presence of patient effort.

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  • Photo-Fenton catalysts supported on microporous materials for industrial pollutant oxidation

    MacDonald, Matthew (2017)

    Doctoral thesis
    University of Canterbury Library

    Industrial pollution remains an issue in many parts of the world. While the problem is localised to certain areas with high densities of heavy industries, the worldwide demand for the products produced means that there is a worldwide responsibility for dealing with the pollution. As some compounds in the wastewater are difficult to treat with traditional methods, new processes must be developed to remove or degrade these pollutants. Advanced Oxidation Processes (AOPs) are a promising method of wastewater treatment that utilize in situ generation of the powerful hydroxyl radical to oxidize pollutants with little to no secondary waste. A significant disadvantage to AOPs is cost, which is compounded by the need for specific reaction conditions, especially pH. Therefore, any catalyst that can widen the range of reaction conditions will help to reduce the cost and improve adoption of AOPs for recalcitrant wastewater treatment. In this work, a novel heterogenous photocatalyst was synthesized by the loading of iron onto the metal-organic framework MIL-47 to create Fe/MIL-47. An iron-zeolite Y catalyst was also synthesized following methods previously reported. These catalysts were then tested for the photo-oxidation of methylene blue, a common model pollutant dye, under UV irradiation. The Fe/MIL-47 catalyst was found to be very effective for both the decolourisation and total organic carbon (TOC) removal at low pH when compared with the iron-zeolite catalyst, with 94% colour removal and 52% TOC removal after 180 minutes for the Fe/MIL-47 catalyst and only 74% colour removal and 8% TOC removal for the Fe-zeolite Y catalyst at the same catalyst loading. The base MIL-47(V) catalyst was also tested and was found to be active for the decolourisation of methylene blue, a result in agreement with previous research that found that other metal-carboxylate frameworks were also photocatalytically active. The Fe/MIL-47 catalyst was found to only be effective over a limited pH range, and therefore a copper MIL-47 catalyst was also synthesized, with a goal of possibly creating a bimetallic catalyst with a wide effective pH range. While the Cu/MIL-47 was indeed found to be active at the higher pH that the Fe/MIL-47 was less active at, the stability of the MIL-47 support was determined to be less than what was necessary for a durable catalyst, and therefore the focus of the remaining studies was shifted to the zeolite based catalyst. While iron-zeolite Y catalysts have been used as heterogenous photocatalysts before, the potential effect of the BrØnsted acid sites on the reaction rate has not been researched. In this section of work, the effect of NH4+, Na+ and H+ in zeolite Y on photo-Fenton oxidation of formaldehyde in a batch reactor was examined. The model pollutant was changed to formaldehyde, as unlike methylene blue, formaldehyde can diffuse within the pore structure of the zeolite, helping to illuminate any effect on the oxidation reaction by the internal pore environment The catalysts were prepared by partial exchange of Fe3+, in the zeolite Y. The charge balancing cations were found to play a vital role in the photo-Fenton oxidation of formaldehyde, with the Fe/zeolite Y catalyst prepared with BrØnsted acid sites (H+) exhibiting three times the reaction rate of the NH4+ or Na+ containing catalysts at pH 7 (TOF are 10.3, 2.7 and 3.4 μmol [mol Fe s]-1, for Fe/H-Y, Fe/NH4-Y and Fe/Na-Y respectively). The results of the study into the charge balancing cations in zeolite Y, did yield an effective photocatalyst at high pH, however the effect was only observable at low catalyst loading (0.5 g L-1), and low iron loading on the catalyst (50% exchanged), limiting the maximum concentration of pollutant that could be treated. Therefore, a bimetallic copper-iron catalyst was synthesized by incipient wetness ion impregnation of zeolite Y with iron and copper ions. This FeCu-zeolite Y catalyst was then tested for the photo-oxidation of methylene blue over a range of pHs. It was found to be effective at both low pH, with 98% colour removal and 89% TOC removal, and high pH, with 99% colour removal and 79% TOC removal. The FeCu-zeolite Y catalyst was also tested under recycle and found to remain effective after 3 runs. The XRD results also showed no loss in crystallinity, indicating the catalyst support continued to be stable throughout the recycle. Collectively, these results present the attempt to create a pH insensitive heterogeneous photo-Fenton catalyst. The MIL-47 based catalyst unfortunately did not have the required stability to fulfil this, however the partially exchanged zeolite Y and the bimetallic zeolite Y catalysts did allow for wider pH range photo-Fenton reactions.

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  • Mapping identity and connection : how first-time mothers make sense of premature birth

    Porter, Lauren Lindsey (2017)

    Doctoral thesis
    University of Canterbury Library

    First time motherhood in the context of premature birth is a specific experience of motherhood that has been relatively unexplored in the literature. This research examined the phenomena of meaning-making, identity formation, and relationship creation by first time mothers following “low risk” premature births. Low risk premature births are moderate and late preterm births associated with a lack of serious, persistent medical concern alongside well understood and effective medical responses. The vast majority of premature births in New Zealand occur in this category and, as with elsewhere in the world, such births are on the rise. While understudied, this subset of premature infants carry significantly more risk factors than their full term peers. Women who become mothers for the first time via the experience of premature birth must negotiate associated stresses, separations, and medical uncertainties in order to come to understand their lived experiences and evolve their identities as mothers. As with their low risk infants, exploration of the processes and perceptions of this group of mothers is underinvestigated. The research employed the qualitative methodology of interpretative phenomenological analysis (IPA) to analyse semi-structured interviews with 15 participant mothers. Findings were generated in response to research questions that focussed on how participants made meaning of the event of premature birth, the relationship with their infants, and their nascent identities as mothers. Three unifying superordinate themes emerged and centred upon the mothers’ unique perspectives of their maternal experience (“Little things are big things”), the maternal distress associated with premature birth (“Maternal experience”), the particular obstacles mothers faced, and the avenues they pursued in an attempt to create a sense of themselves as mothers (“How do I become a mother?”). Findings demonstrated that the identification of mothers and babies as low risk, created a paradoxical situation in which the perception that the babies were healthy and the mothers where healthy and competent actually increased the overall risk for the dyad. Furthermore, the findings suggested that mothers made meaning from within an ecological framework that was dyadic in nature. When mothers were considered outside of this dyadic maternal context—or when their infants were—surplus suffering occurred. Findings have important implications for approaches to psychosocial interventions in neonatal intensive care units (NICUs), including psychological support and social work practice. When professionals are better able to see mothers’ needs where they have been previously concealed, mothers and their infants can be better served. Similarly, when professionals can understand, embrace, and respond to mothers from an awareness of dyadic ecology—what this thesis terms the “dyad-in-context”—approaches to support, advocacy, and treatment can move beyond compartmentalised medicalised approaches to more relational, responsive, authentic ways of being with mothers and their infants.

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  • Global justice awareness? The journey towards transformational learning through international volunteering

    Atkinson, Arthur Laird (2017)

    Doctoral thesis
    University of Canterbury Library

    The opportunity to engage in international volunteering (IV) is a markedly privileged one that this thesis explores through the consideration of a complex range of factors and influences from the global to the personal in an effort to understand how volunteers make meaning of their experiences. IV encompasses a large range of organizations, many of which market volunteering abroad as a mutually beneficial experience for both the volunteer and the host community receiving the volunteers. Links to neocolonialism and neoliberalism, however, have illuminated ethical concerns about how transformation is experienced if host communities are used for the benefit of volunteers. This thesis undertook a mixed methods approach and analysis of three groups of volunteers: those who are currently volunteering, those who have recently returned, and those who have volunteered in years past. Through in-depth interviews and an open-ended survey, this thesis identified four phases of transformation that suggest IV can foster an awareness about global in/justice and that critical self-reflection plays a significant role. Using Mezirow’s theory of transformational learning compliments Bourdieu’s concept of habitus and embodied experience, which implies that volunteers need to be aware of their own habitus, recognizing they may contribute to both systems of injustice and justice. Using this theoretical strategy generated an account of IV as a doubled-edged sword, which signals that there is tension between personal transformation and social justice. Studying IV within a sociological context can contribute to knowledge about how IV programs are situated within a framework of service, influenced by tourism and development, and how they could be better operated within this framework to better foster volunteers’ awareness of inequality and global justice.

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  • Adventures of Categories: Modelling the evolution of categories in land cover mapping

    Gupta, Prashant (2016)

    Doctoral thesis
    The University of Auckland Library

    As research in a specific scientific domain advances, the concepts, methods, models and data all undergo changes and refinements. For some of these scientific artifacts we have developed sophisticated tools to manage versioning; for others, we have little or no record of how they are evolving because they are not represented explicitly or are represented as fixed or atemporal objects. Thus, current computational approaches do little to support the dynamic nature of knowledge and ignore the deeper knowledge and understanding lurking within this flux. Such a situation can result in misinterpretation and a shallow understanding of a scientific enquiry, causing conceptual gaps to emerge between knowledge producers and consumers and inhibiting the reusability of knowledge artifacts. In this thesis, we adopt an alternative view of ???knowledge as process??? and propose a computational model of science where knowledge representation can be seen as an ongoing progression by connecting the products of science with the process of science. We develop a model of category evolution that incorporates representation of (i) the different facets of a category and changes in these facets, (ii) the exploratory and dynamic process of the construction and evolution of categories, and (iii) the contested meanings or multiple perspectives towards categories. The model further incorporates a change language to measure and analyze the changes in different facets, and to compare different categories from the same or different taxonomy. We then present AdvoCate (Adventures of Categories), an eScience tool, that incorporates the evolution model, supporting the process of modelling categories and their changes, while maintaining a versioning system that captures not only the different versions of categories, but also the exploration and evolution steps taken during their creation. The exploration process reveals helpful information regarding how and why changes were made, allowing a knowledge consumer to better understand the biases and decisions made during the process and the reasons behind them. We demonstrate the usefulness of this deeper representation using examples of category evolution from a land cover mapping exercise. The use cases demonstrate how a richer model of category, grounded in the process of science, supports a deeper understanding of scientific knowledge and the process of enquiry, and surfaces up the knowledge hidden within the process of science to support and improve the enquiry process.

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  • Dietary patterns, physical fitness, and markers of cardiovascular health in 9-11 year-old Dunedin children

    Saeedi, Pouya (2017)

    Doctoral thesis
    University of Otago

    Chronic diseases such as cancer, diabetes, and cardiovascular diseases (CVD) are the main health concerns of the 21st century, with CVD as the number one cause of mortality in New Zealand and worldwide. Although CVD hard endpoints such as stroke or heart attacks do not usually occur in children, there is evidence that the manifestation of CVD risk factors begins in childhood, preceding clinical complications of CVD in adulthood. Several factors including biological, environmental, and behavioural factors are associated with the development and advancement of CVD complications. Of these, dietary intake is a modifiable risk factor that has been shown to make a substantial contribution to the risk of death from CVD. Health professionals have long recognised the importance of diets high in fruits and vegetables, wholegrain/high fibre bread and cereals, and limited intakes of sugar and sugar-sweetened beverages in reducing the risk of CVD in adults. However, there is a lack of research in the paediatric population. Thus, the aim of this thesis was to determine associations between dietary intake, particularly dietary patterns as a more global approach of assessing dietary intake and markers of cardiovascular health in 9-11 year-old children in Dunedin, New Zealand. The study was conducted in two phases. In the first phase, a short (28-item) non-quantitative food frequency questionnaire (FFQ) was developed and assessed for its reproducibility and relative validity. Fifty children (mean age±SD: 9.40±0.49 years old) from three Dunedin primary schools completed the FFQ twice, as well as a four-day estimated food diary (4DEFD) over a two-week period. Intraclass correlation coefficients (ICC) and Spearman’s correlation coefficients (SCC) were used to determine the reproducibility and relative validity of the FFQ, respectively. More than half of the food items/groups (52.2%) had an ICC ≥0.50. In relative validity analyses, 70% of food items/groups had a SCC ≥0.30. This FFQ has been used to rank children according to the frequency of consumption of specified food items/groups. The low respondent burden and relative simplicity of the FFQ make it suitable for use in large cohort studies in New Zealand children with similar characteristics. The second phase of the thesis used data from the ‘Physical activity, Exercise, Diet, And Lifestyle Study’ (PEDALS), conducted in 17 primary schools in Dunedin. Of the children who took part in PEDALS, the mean age±SD was 9.72±0.68 years old, 76% were of normal weight, 80% met the guidelines of 60 minutes of daily moderate-vigorous physical activity, and 99% were categorised as fit based on the FITNESSGRAM standards. The first objective of phase II was to identify dietary patterns using principal component analysis (PCA), using the FFQ validated in phase I. Two dietary patterns, namely ‘Snacks’ and ‘Fruit & Vegetables’ were identified. The mean ‘Snacks’ and ‘Fruit & Vegetables’ scores were -0.068±1.98 and -0.005±1.83, respectively. The two identified dietary patterns in PEDALS were similar to commonly identified dietary patterns in both international and national studies. The second objective of phase II was to determine associations between the two identified dietary patterns and components of physical fitness (i.e., cardiorespiratory fitness and handgrip strength). Cardiorespiratory fitness was measured as mean relative V ̇O2max obtained from a 20-metre shuttle run test (20msrt). A digital hand dynamometer was used to measure handgrip strength of both the dominant and non-dominant hands. Complete data was available for 398 participants. Mixed effects linear regression models with robust standard errors and school as a random effect were employed to assess relationships between dietary patterns and components of physical fitness. Mean relative V ̇O2max was 48.7±4.75 ml/kg/min. Handgrip strength of the dominant and non-dominant hand was 15.2±3.29 and 14.4±3.17 kg, respectively. There were no significant associations between the dietary pattern scores and cardiorespiratory fitness. However, fat mass index (FMI) was independently associated with cardiorespiratory fitness. Excess body fat is associated with poorer performance and consequently lower estimated V ̇O2max (ml/kg/min). Furthermore, PEDALS did not find clinically meaningful associations between dietary patterns and handgrip strength of the dominant or non-dominant hand, while sex and fat-free mass index were independent determinants of handgrip strength. Considering the important impact of muscular strength on current and future health status, sex-specific exercise training to improve children’s fat-free mass and muscular strength from as young as 9 years old should be promoted. The third objective of phase II was to investigate relationships between dietary patterns and indices of arterial stiffness (i.e., augmentation index (AIx) and pulse wave velocity (PWV)). Indices of arterial stiffness were assessed using the XCEL system. Data for AIx and PWV analyses were available for 337 and 389 participants, respectively. Mixed effects linear regression models were used to assess associations between dietary patterns and indices of arterial stiffness. Mean AIx and PWV were -2.14±14.1% and 5.78±0.79 m/s, respectively. There were no clinically significant relationships between the dietary pattern scores and AIx and PWV. Arterial stiffness is one of the earliest detectable measures of vascular damage and can be seen in the first decade of life. Although evidence has shown that obesity can accelerate the age-associated arterial stiffening process, the majority (76%) of PEDALS children were normal weight, which may explain the lack of an association. Overall, there were no significant associations between dietary patterns and markers of cardiovascular health in children who took part in PEDALS. The majority of the PEDALS population had a healthy weight status, were of New Zealand European ethnicity, and from families of middle/high socio-economic status. Further research is suggested in a cohort of 9-11 year-old children from families of low socio-economic status and minority ethnic groups such as Māori and Pacific children, using the established methodology of PEDALS. Comparison of the results from PEDALS with a similar study on a group of children with different socio-demographic characteristics would be useful to inform policy and provide further insights on the importance of designing appropriate prevention strategies in both the general and high-risk paediatric populations.

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  • A novel keratin-chitosan-tricalcium phosphate biocomposite as a potential scaffold for regenerative endodontics : an in vitro study

    Ramawarrier, Arunjith (2017)

    Doctoral thesis
    University of Otago

    The present study is the ‘first look’ at a novel biocomposite which may be used as a 3D implantable intracanal scaffold for regenerating dental pulp and periapical tissues. The main ingredient of the biocomposite was low molecular weight keratin protein extracted from sheep wool. Merino sheep wool offers a grand storehouse of keratin proteins which can extracted by many methods. This study used a novel chemical-free method using high temperature and pressure. The extracted proteins were of low molecular weight (3.5-15 kDa) and was water soluble. These proteins were used for the fabrication of the biocomposite along with other ingredients namely chitosan, tricalcium phosphate,barium sulphate and glycerol. This is, perhaps the first study that has explored the use of low molecular weight keratin in biomedical applications. Other constituents of the biocomposite were selected in order to provide specific properties to the composite. Keratin-chitosan formed a mechanically stable homogenous matrix. Chitosan also imparted an antimicrobial potential to the scaffold. Tricalcium phosphate acted as the filler and also a supplier of calcium ions. Barium sulphate provided radiopacity to the scaffold while glycerol was the plasticizer. The scaffold demonstrated many key characteristics relevant to tissue regeneration applications such as adequate porosity and degradation, as well as to endodontic applications such as moderate swelling and radiopacity. Assessment of cytocompatibility yielded promising results. The scaffold promoted proliferation of MDPC 23 (odontoblast like cells) and OCCM 30 cells (cementoblast like cells). The cells were able to grow and achieve functional differentiation when cultured after exposure to scaffold extracts as evidenced by ALP assay which detected elevated ALP levels in culture. AR-S staining detected calcium deposits which further confirmed cell differentiation. Furthermore, immunocytochemical analysis revealed expression of DSPP by MDPC 23 cells which was indicative of odontogenic differentiation. These cell reactions demonstrated the regenerative potential of the biocomposite scaffold. The population density of viable stem cells and their successful differentiation is an absolute prerequisite for successful regenerative pulp therapy, so is the effective disinfection of the root canal system. The antimicrobial potential of the scaffold was tested against S.mutans which was a representative organism for primary infection and E faecalis which represented secondary or re-infection of the root canal system. The scaffold was able to successfully inhibit growth of both the species. This potent antibacterial action of the scaffold eliminated the need for using highly potent antibiotics and other antimicrobials detrimental to host cell survival during endodontic regenerative procedures.

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  • Lymph nodes as a pre-metastatic niche for oral squamous cell carcinoma

    Al Kharusi, Adil (2017)

    Doctoral thesis
    University of Otago

    Background Pre-metastatic niche (PMN) is a new concept in the process of metastasis defined as tumour microenvironment at the future metastatic site which is established by the tumour as a preparation before the arrival of the disseminated tumour cells. Certain cells and cytokines have been reported to be a key factor in building these niches. To date, there is no single study that has investigated the PMN in the oral squamous carcinoma (OSCC). My hypothesis is that IL17, IL22, IL23 and STAT3 play part in the formation of PMN of metastatic OSCC. Aim: To compare the expression of STAT3 and cytokines (IL22, IL23 and IL17) between positive and negative lymph nodes from OSCC. Methods: A total of 36 formalin fixed paraffin embedded (FFPE) tissue specimens were obtained from the Malaysian Oral Cancer Database & Tissue Bank System (MOCDTBS). Sample were divided into two groups. Positive lymph nodes were those with histological evidence of metastatic OSCC while negative nodes were those with no sign of metastasis. Th expression of IL17, IL22, IL23 and STAT3 was investigated using immunohistochemistry (IHC). Gene expression was done using Real time polymerase chain reaction (RT-PCR) to validate the results. Image J was used to count the number of positively staining cells. SPSS was used to analyze the data. Results: IHC results shows that the expression of IL22, IL23 and STAT3 was significantly higher in the negative lymph nodes when compared with the positive group which proof our hypothesis. However, the difference in gene expression was not significant. Conclusion: My results suggest that negative lymph nodes can be a PMN for the OSCC. In addition, IL22, IL23 and STAT3 can be responsible at least partially for the formation of this PMN.

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  • Awareness of pre-radiation dental assessment of head and neck cancer patients among dentists in Malaysia and New Zealand

    Suhaimi, Adlin (2017)

    Doctoral thesis
    University of Otago

    Aims: The aim of this study was to investigate the approaches taken for dental assessment of patients with head and neck cancer (HNCa) by hospital dentists in New Zealand and Malaysia, in order to assist with the development of contemporary uniform guidelines for pre-radiation oral health management. Methods: A review of national guidelines was conducted from United Kingdom, United States, Australia, and New Zealand. A questionnaire-based survey of specialists and hospital dentists working in a hospital setting within New Zealand and Malaysia was undertaken. Information was collected about knowledge of the effects of radiotherapy on the oral environment, current practice regarding the dental management of HNCa patients prior to radiotherapy, guidelines practitioners were currently using and problems that they faced treating HNCa patients. Results: One hundred questionnaires were distributed; 50 for each country and the response rate was 75%. The respondents were consultants/specialist (34.7%), specialist registrars (8.0%), general dentists/ dental officers (38.7%), house surgeons/ first year dental officers (17.3%) and other (1.3%). The majority of respondents stated that multidisciplinary meetings (MDM) were held at their centre (New Zealand- 51.4%; Malaysia - 52.5%) but the health practitioners attending the MDM varied. Only 48.6% New Zealand and 2.5% Malaysian respondents followed formal guidelines or protocols for dental assessment of HNCa patients. Problems that were highlighted included late referral from the medical team, lack of radiation information and inadequate knowledge among the dentists themselves in managing these patients. Conclusion: This study highlights the need for developing clinical guidelines to support effective dental treatment and management strategies for this vulnerable population. Effective communication between health professionals and improved training could enhance patient outcomes.

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  • Effect of nasal high flow therapy on work of breathing and CO2 tension: using an in vitro and mathematical modelling approach

    Adams, Cletus Fiifi (2017)

    Doctoral thesis
    University of Canterbury Library

    A breathing therapy is a technique (invasive or non-invasive) that improves respiration. Nasal high flow (NHF) is a relatively new breathing therapy which involves the delivery of humidified and warmed air via a nasal cannula at a constant flow rate (up to 60 L/min). Conditions alleviated with NHF include sleep apnea, hypercapnic respiratory failure and hypoxemic respiratory failure. The proposed mechanisms of action of NHF include improvement in oxygenation; attenuation of inspiratory resistance; generation of positive airway pressure; and reduction in work of breathing (WOB) (energy expended by the respiratory muscles during breathing). This work was motivated by the scarce data on the effect of NHF on work of breathing and gas exchange. Models of the upper airways of an adult and neonate were 3D printed. A physiologically realistic breathing flow was driven through the models (with a piston pump) along with the recording of tracheal pressure (with and without NHF). Airway resistance (with and without NHF) was defined by the coefficients of a quadratic fit to the tracheal pressure versus breathing flow. This work is the first to estimate airway resistance under NHF conditions in this way. In the adult model, with and without NHF, tracheal pressure during mouth closed breathing was 3 times that of mouth open breathing. Airway resistance increased in an NHF-dependent manner in both breathing directions (inspiration and expiration) and both mouth states of breathing (mouth open and mouth closed). At peak breathing flows of 30 L/min (for the adult model) and 5 L/min (for the neonate model), the neonatal airway resistance was found to be 4 times that of the adult model. The increased pressures generated by mouth closed breathing suggests that the efficacy of NHF at preventing lung collapse (atelectasis) may be improved via closed mouth breathing. A mathematical model for WOB (based on the Otis equation, which uses the experimentally measured airway resistance) was developed by taking into account reported NHF-induced physiological changes in minute volume and I:E ratio. WOB per minute (rWOB/min) during NHF was greater than without NHF, if minute volume did not change with NHF. A fall in minute volume by 40 % reduced rWOB/min by 90 % (at NHF of 60 L/min) compared to a no NHF condition. NHF can drive part or all of the inspiratory breathing flow across the upper airway and produce a fall in inspiratory rWOB/min. The rWOB/min for mouth closed breathing was 3 times that of mouth open breathing assuming equal fall in minute volume. The adult rWOB/min was found to be 16 times that of the neonate. The effect of NHF on alveolar CO2 tension was estimated by metering CO2 at a specific rate into the piston pump chamber and recording tracheal CO2 tension during breathing, with and without NHF. Apnea was simulated by intermittently stopping the breathing flow for a definite time. End-tidal CO2 concentration (EtCO2) reduced with NHF and reached a plateau at NHF of 40 L/min. Compared to breathing without NHF, 40 L/min of NHF reduced the maximum end-tidal CO2 by 18 %, which suggests a lowering of alveolar CO2 tension and rWOB/min (via attenuation of hyperventilation). It is speculated that NHF may ameliorate the frequency of apnea per hour. A two compartment (lung and dead space) mathematical model of the respiratory system was developed to predict EtCO2 tension during apnea under NHF conditions. The model assumed a sinusoidal breathing flow, constant metabolic CO2 production, instantaneous gas mixing and flushing of the nasopharynx by 3 % of NHF. Apnea was modelled by making the breathing flow zero over a definite time. The model capnogram and EtCO2 for apnea, spontaneous breathing and NHF matched those of the bench-top experiment. The EtCO2 at NHF of 30 L/min differed from that of experiment by 0.9 % (V/V).

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  • Phase ordering dynamics in a ferromagnetic spin-1 Bose-Einstein condensate

    Williamson, Lewis Alexander (2017)

    Doctoral thesis
    University of Otago

    Spinor Bose-Einstein condensates exhibit both superfluid and magnetic order, and accommodate phases with rich symmetry properties and topological defects. Transitions between these phases can be induced by tuning external fields. In this thesis we explore the dynamics of order formation in a quasi-2D spin-1 ferromagnetic condensate following a quench from an unmagnetised phase to one of three ferromagnetic phases. The ferromagnetic phases exhibit distinct symmetry properties (easy-plane, easy-axis or isotropic) and support distinct topological defects. In each phase we observe scale invariant ordering and identify the relevant topological defect affecting the order parameter growth. We find that each phase is characterised by a distinct dynamic critical exponent. In the easy-plane phase we identify a persistent turbulent cascade that affects spin ordering long after all topological defects have annihilated. In addition to our exploration of phase ordering dynamics, we study a microscopic model of spin vortex dynamics in the easy-plane phase. Our work provides a comprehensive theoretical study of phase ordering in a conservative system, provides a thorough foundation for studies of phase ordering in antiferromagnetic and higher spin condensates, and offers prospects for further research into fundamental questions regarding the ordering properties of spin systems. Our work is pertinent to current experiments, which have explored the initial stages of phase ordering in both ferromagnetic and antiferromagnetic spin-1 condensates.

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