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Mitigating FMCG transport bottlenecks following an extended Cook Strait ferry outage in Aotearoa New Zealand
No full textThis research aims to understand how an extended Cook Strait ferry outage would impact the movement of fast-moving consumer goods (FMCGs) in New Zealand (NZ). The Cook Strait ferries are critical to the country’s freight system, serving as an extension of the main state highway and rail line connecting the North and South Islands. Despite the significance of the ferries, the ferry terminals are aged and lack redundancy, and they could fail in an earthquake. To understand how an extended terminal outage would impact the movement of FMCGs, data was collected through interviews with 30 industry experts in the transport and FMCG sectors, which was thematically analysed and supplemented with quantitative details to further understand the impact. The findings revealed numerous transport bottlenecks would surface in an extended terminal outage and a lack of preparedness in NZ’s freight system. To guide this research, a set of management tools known as the Theory of Constraints Thinking Process were used, enabling sense to be made of NZ’s domestic freight system following a Cook Strait ferry outage. Using these tools to generate visual diagrams, the cause-and-effect relationships between bottlenecks were identified, root causes were uncovered, and potential solutions were explored. Given that it is not a case of if a major disaster will occur, but when, it is important that progress is made towards addressing the identified root causes so that the impact from future disruptions is minimised and goods can continue moving
Evaluation of New Zealand estuarine water properties using remote sensing
No full textEstuaries and shallow lagoons are the most productive marine systems in the world and contribute to the maintenance of coastal biodiversity by providing various unique habitats for aquatic species. However, due to the inputs of nutrients, sediments and pollutants from the surrounding landscape, light availability and primary productivity can be strongly restricted, which may trigger rapid ecological change over time and cause substantial loss of coastal flora and fauna. This thesis explores the use of Sentinel-2 remote sensing imagery to monitor water properties of shallow intertidal tidal estuaries, for the purposes of managing the estuaries of New Zealand.
The first goal (Chapter 2) was to develop a method to remove the influence of water bottom substrate reflectance in order to detect the true water colour (represented by dominant wavelength) and diffuse attenuation coefficients from Sentinel-2 imagery, in the case study estuary of Tauranga Harbour. The new methodology used direct measurement of bottom reflectance of intertidal areas while exposed, and used a regression estimator to derive subtidal bottom reflectance from particle size (developed using the intertidal properties). The method required the water depth to be known (from LiDAR) and reflectance observations from multiple water depths (either extracted along transects or at the same location at different tides). The method was applied to all available Sentinel-2 images and showed seasonal fluctuations and strong correlations with chlorophyll-a, suspended sediments and coloured metal ions collected by the regional council monitoring programme. This methodology was then applied to 12 estuaries and the results were interpreted in terms of ecological changes (Chapter 5).
The second goal (Chapter 3) was to detect the distribution or density of seagrass/sandflats (where microphytobenthos (MPB) thrive) and use this as a basis to estimate their gross primary productivity (GPP). The new methodology combined Sentinel-2 imagery, machine learning and literature-derived photosynthesis-irradiance (P – I) curves. The machine-learning model included (1) supervised classification with random forest to delineate seagrass and sandflat areas (2) and three machine learning regressions (artificial neural network (ANN), support vector machine (SVM) and random forest regression (RFR)) to predict the density of seagrass. The result showed ANN was the optimal algorithm to predict seagrass coverage. By adjusting the input water depth and light intensity, the methodology could be further developed to predict the response of seagrass and MPB to sea level rise. To counteract the negative impact of increased turbidity caused by coastal erosion and sediment resuspension due to sea level rise and climate change, controlling sediment loading in coastal waters could be an effective solution for maintaining current productivity throughout the entire harbour.
Considering monitoring suspended sediment concentration (SSC) is essential for understanding the resilience of coastal wetlands, a prediction model in Chapter 4 consisting of satellite imagery, numerical simulation and machine learning was developed to enable continuous estimation of SSC. The prediction model included two steps: (1) comparing the Delft3D-derived SSC with corrected satellite data and using K-means classification to categorise the differences into classes; (2) developing a random forest regression model for each class to predict the satellite-derived SSC using Delft3D-derived SSC and other physical parameters. Comparison of the prediction model with in situ measurement showed high accuracy, and the model provided the basis for estimating the accumulated sediment in wetlands. The results showed strong sensitivity to different ways of accounting for incoming SSC supply coastal wetlands. Therefore, employing a model based on real-time observations, like the one developed here, would substantially improve sediment budget estimates in coastal wetlands.
Dominant wavelength and diffuse attenuation coefficients (Kd) can form the basis of ecologically relevant indicators. Therefore, in Chapter 5, classification based on these two indicators was developed to cluster New Zealand estuaries with similar states into groups as a basis for management. The dominant wavelength and Kd were derived from the Sentinel-2 images using the seabed correction model developed in Chapter 2. Three groups, including less impacted, moderately impacted and highly impacted, were created which were in broad agreement with other in situ measurements and indicator models such as those focused on light availability and benthic health. Therefore, satellite-derived dominant wavelength and Kd can be two good indicators to reflect estuarine water properties for management
Analysing A/O possession in Māori-language tweets
No full textThis article contributes the first corpus-based study of possession in Māori, the indigenous language of Aotearoa New Zealand. Like most Polynesian languages, Māori has a dual possessive system involving a choice between the so-called A and O categories. While Māori grammars describe these categories in terms of the inherent semantic relationship between the possessum and possessor, there have been no large-scale corpus analyses demonstrating their use in natural contexts. Social media provide invaluable opportunities for such linguistic studies, capturing contemporary language use while alleviating the burden of gathering data through traditional means. We operationalise semantic distinctions to investigate possession in Māori-language tweets, focusing on the [possessum a/o possessor] construction (e.g., te tīmatanga o te wiki ‘the beginning of the week’). In our corpus comprising 2500 tweets produced by more than 200 individuals, we find that users leverage a wide array of noun types encompassing many different semantic relationships. We observe not only the expected predominance of the O category, but also a tendency for examples described by Māori grammars as A-marked to instead be O-marked (59%). Although the A category persists in the corpus, our findings suggest that language change could be underway. Our primary dataset can be explored interactively online
Role of Seasonal Melt Streams in Heavy Metal and Nutrient Transport from an Antarctic Penguin Colony
No full textDespite the perception that Antarctica is pristine, concentrations of heavy metals and persistent organic pollutants have been recorded at increasing levels. Heavy metals may be present within the Antarctic terrestrial environment through natural geologic processes, long-range atmospheric transport, anthropogenic point sources, and biological transport. While the biological transport of contaminants remains frequently overlooked, in the Arctic, it has been shown to rival atmospheric fluxes of contaminants. Adélie penguins are known vectors for transporting heavy metals and nutrients from within the marine environment and depositing them on the land through guano, feathers, eggshells, and whole carcasses. The incorporation of this material in deep ornithogenic soils has resulted in Adélie penguin colonies being identified as sites of heavy metal and nutrient accumulation. Despite seasonal glacial melt streams that erode these colony soils, their role in heavy metal and nutrient transport is largely under-researched. Therefore, this study evaluated the redistribution of heavy metals and nutrients via melt streams. Stream discharge and load, in addition to soil heavy metal and nutrient content, were also assessed.
Five sites along two streams, one flowing through an Adélie penguin colony (P1 to P5) and a control stream with no penguin influence (C1 to C5), were compared throughout this research. Melt water within the Adélie penguin colony had elevated arsenic, cadmium, and lead (p<0.05), with total heavy metal concentrations exceeding New Zealand freshwater guidelines for ecological health up to 37, eight, and two times, respectively. Cadmium and lead were found mostly in particulate form (dissolved cadmium <22 % and dissolved lead <11 %), however, there was a relatively higher portion of arsenic (up to 72 %) that was dissolved (<45 m). This indicates increased bioavailability and concern for toxicity of arsenic.
Nutrient anions (ammonium, nitrate, and phosphate) were also elevated in penguin-influenced water compared to the control stream (p<0.05), surpassing water quality guidelines up to 1038, 1017, and 551 times. When accounting for differences in discharge, stream loads of heavy metals and nutrients were significantly higher within the Adélie penguin colony (p<0.05), with nitrate and phosphate exhibiting the most prominent differences (p<0.01). In both streams, discharge exhibited large fluctuations on both diurnal and daily time scales (P3 16.7 L s-1 to 53.3 L s-1; C3 10.8 L s-1 to 14.7 L s-1) and was correlated strongly with air temperature (P3 R=0.88, C3 R=0.81). The pH of all stream sites was circumneutral to basic (6.86 to 8.07). This research suggests that seasonal melt streams play a critical role in redistributing potentially toxic levels of heavy metals and nutrients from penguin colonies into the Southern Ocean.
Ornithogenic soil samples from the penguin colony had up to 27, 71, and six times higher arsenic, cadmium, and lead compared to two sampled control soils (p<0.05). Ammonium, total nitrogen, and total carbon were also significantly more enriched with up to 5727, 2454, and 484 times higher concentrations than the control soils (p<0.05). These enrichments were particularly significant with the upper 44 cm. Concentrations of arsenic in the topsoil (0 - 2 cm) and cadmium at soil depths 0 – 44 cm were present in concentrations that exceeded the Canadian ecological quality guidelines for soil. The pH of all soils was neutral to basic (7.78 to 9.86) reflecting the basic basalt parent material. These findings support previous research that ornithogenic soils are sites of heavy metal and nutrient accumulation.
Given the fluctuating nature of melt streams, both daily and seasonally, results are likely to be variable over longer time scales and therefore, more research is suggested to quantify this. Moreover, climate change disproportionately affects polar regions with expected temperature rises. Thus, understanding how melt streams intensify in flow, duration, and transport capacity is an essential area of investigation, to which this research provides important baseline data
A critical race analysis of Māori representation in university strategic documents in Aotearoa New Zealand
No full textFollowing the recent claims lodged at two universities in Aotearoa New Zealand alleging the existence of racism, there has been scepticism towards the professed commitments by universities to create an inclusive and safe environment for Indigenous Māori. As a Kaupapa Māori-informed study, we (a group of Māori and Tauiwi scholars) employed tenets of Critical Race Theory to examine how the representation of Māori is racialised and subordinated in university strategic documents. We located five predominant discourses portraying different mechanisms that reify whiteness in university practices such as the selective interpretation of Te Tiriti articles, targeted recruitment of Māori, framing of Māori as dependent on the Crown to succeed, commodification of mātauranga Māori, and avoidance of conversations about structural racism, colonisation, and racial equity. Our findings suggest that university strategic goal statements need to incorporate a critical race analysis, or else risk perpetuating practices that fall short of challenging the status quo
Intra-species genomic variations in hydrogen-oxidising bacteria is delineated by horizontal gene flow
No full textSpecies are the fundamental unit of ecology and evolutionary biology. However, there is no universal definition of a species that spans all domains of life. Eukaryotic species are traditionally defined through reproductive isolation, where reproductive barriers result in adaptive traits being shared only within the isolated population. Therefore, discontinuities in gene flow in eukaryotes generally result in the formation of an ecologically and genotypically cohesive unit. In contrast, delineating asexual bacterial species is often hampered by extensive horizontal gene flow and is further confounded by the difficulty of identifying a bacteria’s ecological niche. Therefore, the working definition of a prokaryotic species is based on arbitrary standards of relatedness and often lacks a cohesive ecological niche. To address this problem, the ecological population theory, which defines bacterial ‘species’ as ecologically distinct populations delineated through discontinuities in total gene flow, was proposed. It postulates that, rather than a hindrance, the prevalence of horizontal gene flow, primarily through homologous recombination, plays a significant role in bacterial speciation. Horizontal gene flow allows gene-specific sweeps in bacterial populations, where adaptive genes are shared preferentially between recombining bacteria independent of their genomic background. Thus, discontinuities in horizontal gene flow can be utilised to demarcate a genotypically and ecologically cohesive bacterial species.
Previous studies have demonstrated that ecological populations exist in heterotrophic bacteria. However, examining the generalisability of the ecological population theory requires understanding the role of horizontal gene flow in delineating populations from extreme bacterial communities, especially bacteria with limited metabolic redundancy due to their higher impact of deleterious consequences (e.g., pathway dysregulation by recombination of a maladaptive gene) during horizontal gene flow. Therefore, in this work, I utilised the chemolithoautotrophic hydrogen-oxidising Aquificota bacteria from natural populations as a model system to test the generalisability of the ecological population theory. Utilising a novel high-throughput isolation method, I isolated co-habiting Aquificota bacteria with minimal enrichment from geothermal springs. Sequencing and comparative analysis of the Aquificota genomes reveal intra-species genomic variations driven by varying degrees of horizontal gene flow and a population structure composed of co-occurring clonal lineages and recombinogenic bacteria. To examine whether these Aquificota populations exhibit ecological and evolutionary patterns akin to eukaryotic species, I investigated the changes in their population structure across four additional time points (1 year). Analysis of recent horizontal gene flow and mutations in Aquificota populations show that clonal lineages remain clonal across time, with minimal changes in their genomic background diversity. In contrast, recombining populations experience variation in intra-population diversity and a shift in the dominant genomic background across time—implying an intra-population turnover. Lastly, I also investigated the role of both non-homologous and homologous recombination in maintaining ecological populations in Aquificota by analysing the presence and function of mobile genetic elements (MGEs) in its different populations. The lack of spatial and functional overlap between MGEs and horizontally swept regions confirms that homologous recombination drives horizontal gene flow in Aquificota populations.
This work demonstrated that ecological populations in Aquificota can be delineated through discontinuities in horizontal gene flow driven primarily by homologous recombination. Thus, ecological population theory can be a generalisable model for speciation and evolution in bacteria
Sustainable shellfish growth: Investigating microalgae production techniques and species selection for Perna canaliculus larvae in a commercial hatchery
No full textIn order to fulfil the Aquaculture Strategy employed by the New Zealand Government and achieve the goal of increasing industry revenue to $3billion by 2035, more mussel spat hatcheries must be developed to deliver reliable spat supplies. Hatcheries are expensive to operate, especially to produce microalgae for larval feed; therefore, finding the most efficient procedures for spat deliverance and algae production is of utmost importance.
Diets high in Chaetoceros calcitrans supplemented with Tisochrysis lutea are conventionally fed to Perna canaliculus larvae and current production methods are not feasible in a commercial scale hatchery due to the high cost and labour of operating the systems. Therefore, the effect of microalgal diet on larval performance was investigated for two diets significantly reducing the C. calcitrans proportion compared to the conventional diet (control). Furthermore, batch crashes of microalgae are common and disrupt daily operations due to the sensitivity of larvae to changes in food availability or species compositions, which could result in significant setbacks for a hatchery. Therefore, it is necessary to investigate alternative production methods or substitute proportions of the species with an alternative microalgae species. A fourth diet completely substituting T. lutea with Diacronema lutheri was investigated to determine if the species could be interchanged in the case of a batch failure.
Fatty acid analysis alongside indicators such as larval growth, umbo yield, pediveliger yield, spat yield, settlement success, ingestion rates and capture efficiency were investigated to determine larval performance. In contrast to previous studies suggesting that high levels of DHA and EPA are essential for larval growth and survival, there was no clear pattern as to how high DHA and EPA levels benefit larval performance in P. canaliculus. It was found that P. canaliculus larvae fed the lowest proportion of C. calcitrans supplemented with C. muelleri had the lowest EPA content across the larval period but performed the best, in contrast to larvae fed the most EPA rich- diet consisting of C. calcitrans and D. lutheri which performed the worst. Findings from this study imply that it is more beneficial to investigate precursor fatty acids or the sum of n-3 and n-6 fatty acids, opening opportunity for further research to better identify nutritional requirements of P. canaliculus larvae.
In conclusion, a reduction in C. calcitrans did not adversely affect the growth or yield of larvae. In fact, the yields and settlement success were similar to that of the conventional microalgal diet. Therefore, diets with low C. calcitrans replaced by C. muelleri may be better suited for application to a commercial scale hatchery to reduce the strain placed on labour and logistics associated with C. calcitrans batch production. Furthermore, it was found that the use of D. lutheri as a complete replacement of T. lutea is not recommended due to the low larval performance associated with the diet. These findings enable resources and energy to be focussed elsewhere allowing the production of more mussels with lower resource inputs, reducing the environmental footprint of aquaculture operations
Gaining understanding of the effect of alloy composition on the properties of Ti–Cu–Mn–Al alloys
No full textHigh performance cheaper Ti alloys can be developed based on the addition of several alloying elements, amongst which are Cu, Mn and Al. Studies are available in literature about binary and some ternary alloys based on the addition of these elements; however, no quaternary Ti–Cu–Mn–Al alloys were developed. Therefore, in this study quaternary Ti–Cu–Mn–Al alloys were manufactured via powder metallurgy to gain a better understanding of the effect of the alloy composition and the achievable mechanical performance. It is found that the selected quaternary Ti–Cu–Mn–Al alloys are characterised by a lamellar structure, which is progressively refined as the amount of alloying elements increases, and precipitation of the Ti2Cu intermetallic occurs if the Cu content is high enough. The amount of residual porosity increases and changes morphology as more thermal energy is invested in the diffusion of the alloying elements. In terms of mechanical behaviour, the quaternary Ti–Cu–Mn–Al alloys undergo both elastic and plastic deformation upon tensile loading. Strength and hardness linearly increase and the ductility monotonically decreases, which is the result of the compromise between the amount of residual porosity and the several strengthening mechanisms brought about by the actual total amount of alloying elements added
Override and restricted union for partial functions
No full textThe override operation is a natural one in computer science, and has connections with other areas of mathematics such as hyperplane arrangements. For arbitrary functions f and g, f g is the function with
domain dom(f) ∪ dom(g) that agrees with f on dom(f) and with g on dom(g)\ dom(f). Jackson and the author have shown that there is no finite axiomatisation of algebras of functions of signature (). But adding operations (such as update) to this minimal signature can lead to finite axiomatisations. For the functional signature (, \) where \ is set-theoretic difference, Cirulis has given a finite equational axiomatisation as subtraction o-semilattices. Define f g = (f g)∩(g f) for all functions f and g; this is the largest domain restriction of the binary relation f ∪ g that gives a partial function. Now f ∩g = ff\g) and f g = f (f g) for all functions f,g, so the signatures () and (, ∩) are both intermediate between () and (, in expressive power. We show that each is finitely axiomatised, with the former giving a proper quasivariety and the latter the variety of associative distributive o-semilattices in the sense of Cirulis
Are historical perpetual leases on Maori owned land (Native reserves) a basis for currently enforceable fiduciary obligations?
No full textColonial perpetual leases over what were once native reserves continue to trouble the New Zealand government. The colonial Public Trust Office was tasked with managing and administering Māori property affairs, with a focus on the administration of the native reserves. However, if the perpetual leases continue to be viewed through the contractual lens, relief for the Māori landowners will not be forthcoming. Therefore, examining the rationale for imposing fiduciary duties upon the colonial Public Trust Office is essential. Where traditional legal fiduciary literature explores the onerous proscriptive duties that bind persons occupying a fiduciary position, this article establishes that the extensive statutory role assigned to colonial Public Trust officers in managing the native reserves for their Māori beneficiaries created a fiduciary relationship. Moreover, this article shows that, when the colonial Public Trust Office exercised its powers, this often led to conflicts of interest with their Māori beneficiaries