10,007 results for ResearchCommons@Waikato

  • I am Supernova

    Soo, Chin-En Keith (2016)

    Conference item
    University of Waikato

    “I am supernova” is an artistic visualisation of the “The Big Five Personality Test”. The test explores personality of participant with the highly respected Five Factor model (AKA the Big Five). The test result will provide an insight on 5 major dimensions of personality: Openness, Conscientiousness, Agreeableness, Extraversion, and Neuroticism. The numeric indication from the result, score and percentile, will be translated into forms and formations with the help of appropriate assigned colours that best represent the 5 traits.

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  • Place-responsive choreography and activism

    Barbour, Karen (2016)

    Book item
    University of Waikato

    Sensory encounters with place, site and landscape have the potential to stimulate new and deeply felt engagements with local places, and to prompt discussion about the relationships between place, culture and identity. Such sensory encounters may also offer opportunities for critical, reflexive theorising and practice (Pink, 2008, 2009; Stevenson, 2014; Warren, 2012). Within the myriad of potentialities offered in research, a focus on sensory and embodied encounters with local places prompts me to articulate intersections between local issues of social justice and environmental activism and feminist choreography. As a dance artist and researcher, ethnographic research has led me to autoethnographic performance as a specific means to articulate my encounters with place through embodied expression and textual representation.

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  • Physical volcanology of Red Crater, Tongariro

    Bardsley, Candice Joy (2004)

    Masters thesis
    University of Waikato

    The Tongariro Volcanic Centre (TVC) is New Zealand's most recently active volcanic centre and comprises two large active andesitic cones, Ruapehu and Tongariro. Tongariro is a dominantly andesitic cone complex, yet located at its centre is Red Crater, a basaltic andesite vent with an eruptive nature in striking contrast to the rest of Tongariro. The main aim of this research was to reconstruct the eruption history of this vent and provide the basis to model the impact of a range of future eruption scenarios from Tongariro. The Red Crater basaltic andesite vent occupies a small scoria cone (~ 0.3 km³) which has also erupted eleven lava flows including the single largest preserved lava flow on Tongariro, with a length of ~ 7 km and a volume of ~ 0.3 km³. This flow was erupted between 9.7 ka and 3.4 ka, providing a maximum age for the vent. A distinctive feature of this vent is the exposed drained dike in the eastern wall. Clast density (vesicularity), SEM, grain size, and petrographic analysis were undertaken on the deposits erupted from Red Crater, and used to constrain the timing of the lava flows in relation to the construction of the scoria cone. Average vesicularities for the Red Crater scoria deposits, exposed in the eastern and southern crater walls in particular, range from 51.5% to 76.8%, while the range of individual clasts is from 30.5% to 82.1 %. These values classify Red Crater scoria as highly vesicular. This scoria section is ~ 60 metres thick and possibly erupted within a 48 hour period. The five lava flows erupted prior to this scoria cone construction (pre 1.85ka Taupo eruption) are andesitic blocky flows, with lengths up to ~ 7 km and thicknesses up to ~ 50 metres. Five basaltic andesite aa flows were erupted post 1.85ka and coincided with the construction of the scoria cone. Maximum thicknesses are ~ 5 metres with lengths up to 0.98 km. The change in composition of the lava flows at this time is reflected by a change in the eruptive processes. Effusive activity dominated pre 1.85 ka while strombolian style eruptions producing discrete gas bursts dominated during the scoria cone construction post 1.85 ka. Two dikes are intruded into the scoria cone; one is the eastern wall and the other in the western wall. The eruptive history of Red Crater can be divided into three phases. Phase one was probably initiated with a violent phreatic eruption caused by the interaction of an intruding dike with groundwater. The loss of volatiles during this phreatic eruption and through the permeable country rock lead to sustained effusive activity which produced the five andesite flows into Oturere Valley. Phase two began when more basaltic magma was injected into the system, with strombolian eruptions rapidly building the scoria cone and erupting the remaining six basaltic andesite lava flows. The basaltic andesite flow (flow 9) into Central Crater has the most mafic composition of any lava flow from the entire Tongariro cone complex. Phase three began when the withdrawal of magma from the dike caused a series of phreatic explosions originating from the deeper section of the NE-SW orientated dike, which violently excavated the NE trending Emerald Lakes explosion pits, the northern section of the scoria cone and the explosion pit on the south face of the cone. Minor ash and steam eruptions have been observed at the end of the last century, but it is the active fumaroles surrounding the vent which reveal Red Crater's currently active state, and potential for future eruptions.

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  • Animal olfactory detection of human diseases: Guidelines and systematic review

    Edwards, Timothy L.; Browne, Clare M.; Schoon, Adee; Cox, Christophe; Poling, Alan (2017)

    Journal article
    University of Waikato

    Animal olfactory detection of human diseases has attracted an increasing amount of interest from researchers in recent years. Because of the inconsistent findings reported in this body of research and the complexity of scent-detection research, it is difficult to ascertain the potential value of animal detectors in operational diagnostic algorithms. We have outlined key factors associated with successful training and evaluation of animals for operational disease detection and, using these key factors as points for comparison, conducted a systematic review of the research in this area. Studies that were published in peer-reviewed outlets and that described original research evaluating animals for detection of human diseases were included in the review. Most relevant studies have assessed dogs as detectors of various forms of cancer. Other researchers have targeted bacteriuria, Clostridium difficile, hypoglycemia, and tuberculosis. Nematodes and pouched rats were the only exceptions to canine detectors. Of the 28 studies meeting inclusion criteria, only 9 used operationally feasible procedures. The most common threat to operational viability was the use of a fixed number of positive samples in each sample run. Most reports included insufficient information for replication or adequate evaluation of the validity of the findings. Therefore, we have made recommendations regarding the type of information that should be included when describing research in this area. The results of this systematic review suggest that animal detectors hold promise for certain diagnostic applications but that additional research evaluating operationally viable systems for olfactory detection of human diseases is necessary.

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  • Using machine learning techniques to track individuals & their fitness activities

    Reichherzer, Thomas; Timm, Mikayla; Earley, Nathan; Reyes, Nathaniel; Kumar, Vimal (2017)

    Conference item
    University of Waikato

    The use of wearable devices for fitness and health tracking is on an upward curve with a range of devices now available from a number of manufacturers. The devices work with smart devices to exchange data via Bluetooth communication protocol. This paper presents the results of an initial study on the security and privacy weaknesses of wearable fitness devices. It discusses methods to 1) capture and process data sent from a wearable device to its paired smartphone during synchronization and 2) analyze the records to track individuals and make predictions. The data analysis methods use supervised machine-learning techniques to train a classifier for associating synchronization records with the individuals, their physical activities, and conditions under which they were performed. Results of the study show that the methods allow individuals and their activities to be tracked, both of which infringe on the privacy of the user. The paper also provides recommendations on improving the security of wearable devices based on the initial research results.

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  • The International Journal of Wellbeing: An open access success story

    Weijers, Dan M.; Jarden, Aaron (2017)

    Book item
    University of Waikato

    Academics have long had the advantage of access to university libraries and their expensive subscriptions to scholarly journals. Critics of traditional journal publishing have complained that placing science and scholarship behind a paywall limits its potential. One solution to this problem is the emergence of open access journals. In this chapter, authors Weijers and Jarden offer a case study of a platinum open access journal they founded: the International Journal of Wellbeing. In their discussion of this new journal they offer both philosophical and practical insights that guide their work. They also point to often overlooked issues regarding open scholarship. One of these is the huge numbers of unaffiliated faculty or faculty from non-Western universities, all of whom suffer barriers to access to expensive journals. The authors look to increasing openness of journals to solve this and other problems.

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  • Considerations on the effect of solutal on the grain size of castings from superheated melts

    Bolzoni, Leandro; Babu, Nadendla Hari (2017)

    Journal article
    University of Waikato

    The amount of solutal present in an alloy affects the grain size of the cast metal as solute is rejected at the solidification front. This is normally quantified using the so called growth restriction factor Q. This work presents some considerations about the effect of solutal on the final cast structure with a focus on the nature of the alloy system, the effect of non-equilibrium solidification conditions and the effect of superheating of the molten metal.

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  • The Effect of Nitrate Supplementation on Cycling Performance in the Heat in Well-Trained Cyclists

    McQuillan, Joseph A.; Casadio, Julia R.; Dulson, Deborah K.; Laursen, Paul B.; Kilding, Andrew E. (2017)

    Journal article
    University of Waikato

    Purpose: The aim of this study was to determine the effect of NO₃⁻ consumption on measures of perception, thermoregulation and cycling performance in hot conditions. Methods: Using a randomised, double-blind, crossover-design, 8 well-trained cyclists (mean ± SD: age: 25 ± 8 y, V̇O2peak: 64 ± 5 ml·kg⁻¹·min⁻¹) performed 2 separate trials, in hot (35°C, 60% relative humidity) environments, having ingested either 140 ml NO3--rich beetroot juice ~8 mmol NO₃⁻ (NIT), or placebo (PLA), daily for 3-days with a 7-day washout period separating trials. Trials consisted of 2 × 10 min bouts at 40 and 60% peak power output (PPO) to determine physiological and perceptual responses in the heat, followed by a 4 km cycling time-trial. Results: Basal [nitrite] was substantially elevated in NIT (2.70 ± 0.98 μM) vs PLA (1.10 ± 0.61 μM) resulting in a most likely (ES = 1.58 ± 0.93) increase after 3-days. There was a very likely trivial increase in rectal temperature [Tᵣₑ] in NIT at 40% (PLA;37.4 ± 0.2°C vs NIT;37.5 ± 0.3°C, 0.1 ± 0.2°C) and 60% (PLA;37.8 ± 0.2°C vs NIT;37.9 ± 0.3°C, 0.1 ± 0.2°C) PPO. Cycling performance was similar between trials (PLA;336 ± 45 W vs NIT;337 ± 50 W, CV±95%CL; 0.2 ± 2.5%). Outcomes for heart rate, and perceptual measures were unclear across the majority of time-points. Conclusions: Three days of NO₃⁻ supplementation, resulted in small increases in Tᵣₑ during low- to moderate-intensity exercise, however this did not appear to influence 4 km cycling time-trial performance in hot climates.

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  • Enabling collaborative review with the DSpace configurable workflow

    Schweer, Andrea; Barr, Jenni; Congdon, Deirdre; Symes, Megan (2017)

    Conference item
    University of Waikato

    The DSpace configurable workflow feature enables the creation of custom review workflows beyond the traditional edit metadata, accept, reject actions. This poster reports on our experiences in using the customisable workflow to enable collaborative review by repository management staff for the AgResearch institutional research repository, AgScite.

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  • Urban Rural Differences in Breast Cancer in New Zealand

    Lawrenson, Ross; Lao, Chunhuan; Elwood, Mark; Brown, Charis; Sarfati, Diana; Campbell, Ian (2016)

    Journal article
    University of Waikato

    Many rural communities have poor access to health services due to a combination of distance from specialist services and a relative shortage of general practitioners. Our aims were to compare the characteristics of urban and rural women with breast cancer in New Zealand, to assess breast cancer-specific and all-cause survival using the Kaplan–Meier method and Cox proportional hazards model, and to assess whether the impact of rurality is different for Māori and New Zealand (NZ) European women. We found that rural women tended to be older and were more likely to be Māori. Overall there were no differences between urban and rural women with regards their survival. Rural Māori tended to be older, more likely to be diagnosed with metastatic disease and less likely to be screen detected than urban Māori. Rural Māori women had inferior breast cancer-specific survival and all-cause survival at 10 years at 72.1% and 55.8% compared to 77.9% and 64.9% for urban Māori. The study shows that rather than being concerned that more needs to be done for rural women in general it is rural Māori women where we need to make extra efforts to ensure early stage at diagnosis and optimum treatment.

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  • Psychometric properties of the movement-specific reinvestment scale for Chinese children

    Ling, Fiona C.M.; Maxwell, Jon; Masters, Rich S.W.; McManus, Alison M.; Polman, Remco C.J. (2016)

    Journal article
    University of Waikato

    The propensity for movement-specific reinvestment (conscious attention to and control of body movements) is associated with disrupted movement in a variety of circumstances. Movement-specific reinvestment has been shown in adults but not in children, as a validated psychometric instrument for children does not exist. The aim of this study was to examine the psychometric properties of a movement-specific reinvestment scale adapted specifically for Chinese children (MSRS-CC). Five hundred and thirty-two Chinese pre-adolescents aged 7–12 yrs completed the MSRS-CC and a sub-sample completed the questionnaire again three weeks later. Another sub-sample also completed the Coordination and Health subscales of the Physical Self-Description Questionnaire (short form; PSDQ-S). All questionnaires were completed during normal school days. A random half of sub-sample two completed the MSRS-CC before the PSDQ-S and the other half completed the questionnaires in reverse order. Confirmatory factor analyses demonstrated sound internal validity for the Scale's two-factor model. Acceptable internal reliability and satisfactory test–retest reliability were evident. Convergent and discriminant validity with the Coordination and Health subscales of the PSDQ-S was also tested, but the former was unexpectedly low. Future research using objective measures of motor proficiency was recommended. The MSRS-CC is potentially a valuable tool for understanding movement control by children in research as well as in clinical and educational settings.

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  • River Mouth Processes and Morphodynamics on a Mixed Sand-Gravel Beach

    Paterson, Adam Karl (2000)

    Masters thesis
    University of Waikato

    Where the Ashburton river meets the sea it is impounded by a mixed sand-gravel barrier, formed through littoral transport of sediment, causing a lagoon to form, locally referred to as hapua. From the hapua, discharge to the sea is maintained through small, ephemeral channels, which are unstable and are subject to morphological change in response to fluctuations in longshore transport of gravel and variations in river flow rate. There are few descriptions of the morphodynamics of these highly changeable features, particularly changes that occur over short time scales of hours to weeks. To investigate the patterns and processes involved in the migration of drainage channels, several new instruments were trialed. A methodology of was developed to provide estimates of longshore transport on a gravel beach using a Gravel Transport Sensor. Video camera technology was the primary tool used to study river mouth morphodynamics. The camera provided hourly images of the environment, enabling qualitative assessment using movies of the images to observe morphologic changes, and quantitative measurement of the migration of the channel. Measurements of river flow, wave climate and lagoon water levels were also gathered to investigate the relationships between the morphological response and the forcing factors. Results of the study showed that the ends of the channel behave differently, with the lagoon end remaining more stable than the seaward end. The seaward end is more exposed to the high wave energy prevalent along this coast. The wave climate, especially wave period and direction, were found to be predictors for the migration rate. The location of the seaward end is more variable due to the fluctuations in wave climate, differing from the lagoon end which is influenced predominantly by river flow rates. It has been found that the migration of the lagoon end occurs in 'steps', which are separated by raised gravel banks, the single persistent feature throughout the study. This stepping migration is driven primarily through episodic events such as high river flow or large wave events.

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  • Henri Lefebvre on education: Critique and pedagogy

    Middleton, Sue (2016)

    Journal article
    University of Waikato

    The ‘spatial turn’ in education policy studies fuelled interest in Lefebvre’s work: initially, in his work Production of Space and, more recently, Rhythmanalysis and Right to the City. Yet, although in these texts Lefebvre critiques universities and schools and introduces original pedagogical concepts, their educational strands have attracted little attention. Lefebvre’s other works available in English have been largely overlooked in education literature. As France’s first Professor of Sociology, Lefebvre was passionately engaged with education: in particular, teaching, competing for government grants and leading student activism. Critiques of education are threaded through Lefebvre’s three-volume Critique of Everyday Life, his writings on architecture and anthologies. Lefebvre’s work, The Explosion, is surprisingly neglected. A critique of French universities, it analyses student protests across Paris in 1968 – events in which Lefebvre was a leading activist. In geography and philosophy there are burgeoning secondary literatures on Lefebvre. Laying groundwork for such a literature in education, I survey Lefebvre’s references to education in all the works available in English. Arguing that Lefebvre was an educational thinker in his own right, this paper sketches a ‘roadmap’ for educational readings of Lefebvre’s prolific and largely sociological writing. This paper falls into three parts. The first uncovers core Marxist and phenomenological foundations of Lefebvre’s critiques of universities and schools. Building on these, it introduces Lefebvre’s pedagogical concepts. The second part contextualises these in relation to ‘New’ (or ‘Progressive’) education movements at ‘critical moments’ of 20th-century history. It includes a case study of one such moment – the 1968 Parisian student uprising – then outlines Lefebvre’s summation of education in the late 20th century. The third part draws together four ‘Lefebvrian’ pedagogical principles and considers their relevance today. Educational readings of Lefebvre, I suggest, can help educationists identify ‘cracks or interstices’ in ‘technocratic rationality’, suggesting strategies for resisting contemporary neo-liberal regimes.

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  • 'Assessment in ECE is overwhelming at times': Uncovering the challenges of assessing four-year-old children’s learning

    Cameron, Monica; McLachlan, Claire; Rawlins, Peter (2016)

    Journal article
    University of Waikato

    This article presents some of the preliminary findings from a national survey which explored early childhood teachers’ understandings, beliefs and practices in relation to assessing four year old children’s learning. While a range of perspectives in relation to assessment were evident in the survey responses, this article focuses on the issues and challenges identified by teachers. Some suggestions regarding possible next steps are also made. The findings presented here are a small, but important, element of a larger study. Further analysis of the data collected during both phases is currently being undertaken and additional discussion and dissemination will follow.

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  • Intentional over-qualification: An exploration of motives and outcomes

    Newland , Samantha (2017)

    Masters thesis
    University of Waikato

    The effects of over-qualification (OQ) are becoming more established, yet little is known about the processes which drive these outcomes, or why outcomes are sometimes positive rather than negative. Less is known about different forms of over-qualification, whether they exist, and, whether they make a difference to such outcomes. Drawing on the theory of needs-supplies fit, the current research examined how two distinct forms of over-qualification (intentional and unintentional) relate to life satisfaction, job satisfaction, organisational commitment, turnover intentions, and job performance. Data were collected by means of an online self-report survey. Two hundred and twenty-seven respondents (61% female, 39% male) provided data at one time point. Two distinct forms of over-qualification emerged. Ninety participants were intentionally over-qualified and predominantly chose jobs below their qualifications due to work-life balance considerations (e.g., wanting more time for educational pursuits, family, hobbies, and leisure activities). Eighty-four participants were unintentionally over-qualified (i.e., not over-qualified by choice), and fifty-three participants were not over-qualified. Women reported choosing jobs below their qualifications significantly more often than men, as did individuals below the age of 30 years. Unintentional over-qualification proved to be a more harmful form of over-qualification and was linked to a range of undesirable outcomes. Over-qualified employees should not be mass categorised as they have been in many previous studies. Although unintentional over-qualification should be avoided, the same cannot be said for intentional over-qualification. Over-qualified individuals who choose their employment situation appear to represent a largely unrecognised, underutilised, and potentially valuable resource for organisations.

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  • The Food Sovereignty Challenge to the Corporate Food Regime: Food for Thought

    Howard, Darelle Jane (2017)

    Masters thesis
    University of Waikato

    This thesis forms part of an ongoing project working with Neilson (2012; Neilson & Stubbs, 2016) towards a revised version of regulation theory that is still a workin-progress. I have struggled towards a conceptual framework that distinguishes key concepts ‘model of development’, ‘food regime’ and ‘agricultural system’. I argue that this conceptual framework enables a more thorough analysis of the current era and also provides a tool for conceptualising a new one. I extend on the standard accounts of the concept ‘food regime’ (Friedmann, 1987; McMichael, 1992; 2009b) and attempt to more clearly delineate what I call the ‘agricultural system’, from the regulation/accumulation coupling (i.e. model of development). The corporate food regime while being essentially equivalent to the neoliberal model of development in agriculture, remains distinct from it because the food regime includes, yet is still distinct from, the prevailing model of development which over time transforms the pre-existing regulatory framework of the food regime. Using my conceptual framework, I critique the dominant agricultural system as environmentally destructive and (key to my project) undermining of food sovereignty. The dominant agricultural system is influenced by, though not solely or directly, the prevailing corporate food regime. The current food regime is largely responsible for the threat to food sovereignty in the current era. However, food sovereignty is an inclusive movement that challenges the dominant agricultural system and I put forward the argument that a new food regime should be premised on food sovereignty. I investigate emerging agricultural systems in Rome in order to think about the practical realities of alternatives to the dominant agricultural system that are based on food sovereignty. My field research was based on in-depth interviews using a qualitative approach. I looked at both production and consumption elements of an emerging agricultural system – central to any economic system. I met with GAS Testaccio Meticcio and three local producers, La Nuova Arca, Barikamà and Il Papavero. I pursued a multi-level research agenda that is theoretically informed and grounded in a sense of the big picture and an associated political agenda, and yet goes all the way down to the micro-level of empirical field research. My thesis is structured following this multi-levelled agenda. Beginning with the theoretical foundations I move to a national experience before honing down on the substantive emergence of agricultural systems in Rome. Finally, I integrate these levels in a discussion of a new food regime. Advocating for structural changes that focus on improving food sovereignty is by no means an original stance. However, my contribution comes from my core argument that the best chance of achieving such goals is through the conceptualisation and implementation of a new food regime. The centre-piece of such a regime needs to be a national template and practical strategy for promoting food sovereignty. Although I have made progress developing my revised account of the relationship between regulation and accumulation in agriculture, there are limitations to my framework which I will continue to work on.

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  • Causes of diurnal ground movements at Omokoroa, New Zealand

    Manderson, Tyler Peter (2017)

    Masters thesis
    University of Waikato

    This study investigated processes acting on the Bramley Drive Landslide, located on the Omokoroa Peninsula. The landslide, first failed in 1979, and has become an important field site for assessing the processes affecting sensitive volcanic soils in the Bay of Plenty region that contribute to slope failure. Researchers from the University of Waikato and the University of Bremen, Germany observed daily displacements in a borehole inclinometer located on site that were attributed to amplification of Earth tide movements. Potential factors contributing to exaggerated diurnal solid Earth tide strains were investigated, primarily: temperature, rainfall, Earth tides and microseisms. Measurements of displacements and forcing processes were obtained using a 3-axis 0.65 g precision accelerometer/seismometer, borehole inclinometer and weather station. The accelerometer data indicate that microseisms, consistent with breaking waves on the open coast of Matakana Island, and a diurnal thermal component occur within the top 5cm of the ground profile. The measured ground accelerations are greatest in warmer summer months due to the larger changes in temperature throughout a day associated with higher insolation and reduced soil moisture. The displacements within the borehole are a linear function of depth, but involve a series of sharp deviations, or steps, throughout the 42 m length measured. These steps coincide with boundaries between different stratigraphic units, usually where there is a change in soil type and soil strength. Therefore, the effects of the horizontal strain due to the solid Earth tide is exaggerated by differential and lagged displacement of the units. This suggests that Earth tidal stress, may cause minor (usually temporary) shear surfaces at depths that may be the final trigger for an “at risk” slope that is already preloaded and ready to fail. Several examples where this may be a factor were identified, including all the events at Bramley Drive with a known time of failure. Failure occurred when the rate of vertical Earth tide displacement peaked close to the time of maximum horizontal displacement, which corresponds to a change in the direction of the stress caused by the combined Moon and Sun tide generating potential. Predicting the time of slope failure may be beneficial both locally and globally.

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  • Editorial [New Zealand Journal of Zoology, Vol. 40, No. 4]

    King, Carolyn M. (2013)

    Journal article
    University of Waikato

    It is now almost 4 years since the New Zealand Journal of Zoology (NZJZ), as one of the Royal Society of New Zealand’s journals, partnered with Taylor & Francis, and the benefits to its extended family of authors, referees, subscribers and readers continue to accumulate. Taylor & Francis’ efficient online manuscript handling and marketing systems are reaping many rewards, visible in their annual reports of journal statistics.

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  • 3D Printing of Natural Fibre Reinforced Recycled Polypropylene

    Stoof, David; Pickering, Kim L. (2017)

    Conference item
    University of Waikato

    The adverse effects that waste plastics are having on the environment is becoming increasingly apparent. However, the plastics recycling industry in New Zealand is entirely market driven, necessitating the development of new markets to account for increasing quantities of waste. Innovations in additive manufacturing (AM) have presented opportunities to recycle thermoplastics for use as AM feedstock material. Using waste thermoplastic materials to fabricate composites in this way, adds value to the polymer by enhancing mechanical and aesthetic properties. A range of composite filaments with differing fibre and gypsum weight contents were then produced using pre and post-consumer polypropylene (PP). The most successful filaments in terms of tensile properties consisted of 30 wt% harakeke in a post-consumer PP matrix which had a tensile strength and Young’s modulus of 41MPa and 3.8 GPa respectively. Comparing these results to those of plain PP filament, showed improvements in tensile strength and Young’s modulus of 77% and 275% respectively. Finally, a novel method of measuring shrinkage in 3d printed components was developed and used to compare relative shrinkage of different composites. The composite that showed the least shrinkage consisted of 30 wt% harakeke with a shrinkage value of 0.34% corresponding to a net reduction of 84% relative to plain PP.

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  • Invasive fish survey of Lake Arapuni by boat electrofishing

    Tempero, Grant Wayne; Powrie, Warrick; Kim, Brian (2017)

    Report
    University of Waikato

    A boat electrofishing survey of Lake Arapuni was conducted on 2 February 2017 by the University of Waikato to investigate anecdotal reports of koi carp (Cyprinus carpio) presence in the lake. Nine 10-minute electrofishing transects were conducted around the littoral zone of the lake. This resulted in a total distance fished of 3.35 km and a total area fished of 1.34 ha. A total of 100 fish were captured, comprising three species: brown bullhead catfish (Ameiurus nebu/osus), goldfish {Carassius auratus) and rudd {Scardinius erythrophthalmus); in addition, eels (Anguilla sp.) were observed but not captured. Total captured fish biomass was 14.8 kg {11. 7 kg/ha) with goldfish being the most abundant species (86 individuals), accounting for most of the biomass (86.8%). Rudd were the next most abundant species with nine individuals captured (1.0 kg/ha) followed by catfish (five individuals; 0.4 kg/ha). Rudd and catfish boat electrofishing biomass estimates should be regarded as minimal as capture rates for benthic species (catfish) and juveniles (rudd) are often lower than those of adult pelagic species. The reduced capture efficiency of benthic species is due to their preference for depths beyond the extent of the electrofishing field (approximately 2 m in extent from the anode), in addition benthic species are more likely to be missed by netters due to their reduced visibility. The smaller size (150 mm FL), many of which were highly coloured and had markings similar to those of koi carp. It is likely that these larger coloured goldfish were mistaken for koi carp in previous sightings, especially as adult goldfish form small aggregations similar to those of koi carp. If koi carp are present in Lake Arapuni they are likely to be at biomass levels too low to mount viable control or eradication programmes given the large area and depth of the lake.

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