Minerva Elements Records
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ItemMindfulness in Education: Critical Debates, Perspectives, and Pragmatic Recommendations( 2023-11)Interest in mindfulness for education has burgeoned. However, this growth in interest is followed by emerging debates and criticisms regarding the intentions and the social and political implications of integrating mindfulness into schools and universities. While scholars have increasingly attended to these critiques and criticisms, it is unclear how these issues and concerns may translate into practical considerations for educational leaders, policy makers, and stakeholders. This dissertation sought to explicate foundational discussions on three critical considerations for mindfulness in education: 1) a persistent tension between the need to adapt mindfulness for contemporary and secular applications, while preserving the integrity of the practice; 2) the social and political implications arising from implementing mindfulness amidst a context of neoliberalism, commercialism and consumerism; and 3) the nascent status of existing empirical evidence on mindfulness, and a limited research understanding of the potential adverse effects of mindfulness-based programs/practice, when done with children and adolescents, especially those with a predisposed vulnerability. This dissertation offers pragmatic recommendations to address each of these critical considerations. To provide empirically grounded insights into the three critical considerations for mindfulness in education, this dissertation presents three research studies which examined educators’ and university-attending emerging adults’ perspectives on mindfulness in education, and their experiences with mindfulness practice and mindfulness initiatives provided by their educational institutions. The findings provide support to the acceptability of mindfulness, as a universally applicable, suitable and beneficial approach to mental health and well-being, among educators and university students. In general, educators’ and university students’ perceived purpose and motivations for practicing mindfulness tended to reflect ‘thin’ and ‘instrumental’ goals, which align with the commonly proposed aims of the practice, both in the literature and in popular culture. Concerns relating to potential religious conflicts and adverse effects from mindfulness practice were raised by few educators. In addition, educators valued independent research evaluation of mindfulness in education, though they lacked confidence in the current state of research. Overall, educators believed that mindfulness was valuable to education, and was beneficial to practice by students and educators regardless of their age or religious backgrounds. However, educators emphasised on the importance of committing to ‘proper’ implementation of mindfulness in education, in order for such a movement to have positive impact on education. These results are discussed in light of the proposed critical considerations. Further contribution of the dissertation to the topic is discussed and future directions for research are proposed.
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ItemQuasar Broad Emission Line Regions and Gravitational Microlensing( 2023-08)This thesis has focussed on hydrogen and helium emission line generation in the Broad Emission Line Region (BELR) of quasars and also on the gravitationally lensed quasar LBQS1009-0252. Quasars are a class of galaxy characterised by an active nuclear region in which a high rate of accretion onto a central supermassive black hole results in the release of vast amounts of broadband energy over a prolonged period of time. These incredible luminosities—often up to 100,000 times that of a standard galaxy—make quasars some of the most distant, and therefore earliest, sources ever observed in the universe. The relatively tiny size of the innermost region, however, precludes direct observation, and so the physics and geometry of quasars remains enigmatic. Emitted by the accretion disk, light interacts with surrounding gasses in the BELR—so-named because light which is reprocessed and re-emitted from this region tends to be significantly broadened due to wholescale Doppler motions of the gas. As the first gas to ‘see’ light from the accretion disk, understanding and constraining the nature and dynamics of the BELR remains of interest in many astrophysical fields. Following methods pioneered by Ruff (2012), microphysical simulations (such as those produced by the photoionisation code, Cloudy) can be combined with observed spectral data of real sources to model hydrogen line emission from the BELR. This research has confirmed and built further upon the methods presented in Ruff (2012) through the use of updated code and new, high-quality NIR spectral data of 14 quasar sources acquired from the Flamingos-2 (F2) instrument on Gemini South at the Gemini Observatory. The thesis has also gone a step beyond the original method and includes the modelling and analysis of helium emission lines for the first time. Broadly, the results lend support to the conclusions presented in Ruff (2012): hydrogen lines tend to be produced optimally in regions of low incident ionising flux and high gas number density. Helium lines also appear to follow this trend, clustering in a similar parameter space, although there appears to be a tendency towards a flatter distribution across the value for maximum gas number density. This suggests that despite similarities in their physical production and spectral appearance, there are some slight differences in the behaviour of hydrogen and helium emission lines in the BELR, and it is prudent to analyse them separately where possible. This thesis also examined the double-image gravitationally lensed quasar, LBQS1009-0252, via new and relatively high-resolution data from the Gemini Multi-Object Spectrograph (GMOS) at Gemini Observatory. The project investigated both the emission and absorption lines present in the spectra of components A and B, seeking to better understand the spectral differences apparent between the two images. The analysis confirms that the LBQS1009-0252 system likely consists of two images of the same, gravitationally lensed background quasar source, with a third component, LBQS1009-0252C, most likely a foreground and physically unrelated quasar. A comparison and analysis of the overall spectra and emission lines attempts to separate the effects of different light paths through the lensing galaxy, previously identified at z~0.869. A combination of differential extinction due to dust in the macrolens plus a minor component of microlensing is a reasonable explanation for the origin of chromaticity between the spectra of the two component images. The new dataset was of high resolution, allowing for the identification of many more absorption lines than had previously been catalogued. These have been matched to those previously classified as belonging to the lensing galaxy and another known absorber situated at z~1.627. Newly-observed lines were analysed to identify likely absorption species candidates, showing that the presence of at least one more intervening absorption system at z~1.116–1.117 is highly likely.
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ItemMechanisms of ergodicity breaking - from time crystals to Hilbert space fragmentation( 2023-11)The concept of ergodicity reaches back to Boltzmann’s attempts at formalizing and clarifying the foundations of statistical mechanics. The postulate of thermal equilibrium seems to describe the behavior of sufficiently complex real-world systems, whether they are classical or quantum, exceedingly well. However, our understanding of the fundamental laws of physics that govern the dynamics of these systems on a microscopic scale can at first glance seem incompatible with this postulate. A complete description of the dynamical process of thermalization is subject of ongoing research even more than a century after Boltzmann’s contribution. Significant advances have been made, including a formal description of this process in the context of closed quantum systems that is linked to properties of its energy eigenstates. Besides deepening our understanding of what seems to be quite generic behavior, the possibility of robust exceptions to the fundamental postulates of thermodynamics have been unveiled as a consequence. Among them are potentially novel phases of matter, such as many-body localization, time crystals and Hilbert space fragmentation, that do not readily fit within the usual frameworks of phase transitions and may even find application in quantum technologies. In this thesis, I discuss the current state of research in regards to thermalization in quantum systems and some of the presumable exceptions. I then present my own contribution to the field in the form of published works on time crystals and fragmentation. In particular, I demonstrate the realization of a discrete time crystal on a quantum computer, a rapidly evolving technology at the forefront of quantum information science that promises to revolutionize our ability to model and simulate quantum systems. The demonstration of a novel phase of matter in the form of a time crystal represents one of the first successful applications of a quantum device in the field of quantum many-body physics. Furthermore, I present results on interaction-induced fragmentation that address questions about the relationship between localization and fragmentation. They also demonstrate possible transitions between different dynamical regimes within a fragmented system based on tunable emergent conserved charges. Lastly, I present work on the robustness of Hilbert space fragmentation under more general perturbations than are typically considered in other works. Introducing a new definition of block inverse participation ratio, I show that fragmentation may constitute a finite regime within the space of Hamiltonians with a possible phase transition into ergodic dynamics, with the block inverse participation ratio serving as the order parameter.
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ItemReducing nitrogen loss and odour generation from broiler litter: the effect of lignite on litter physical, chemical and biological properties( 2024-02)In Australia, broiler production generates substantial quantities of organic waste, predominantly in the form of spent litter. This litter, composed of bird excreta, bedding material, spilt feed, and feathers, is a rich source of carbon (C) and nitrogen (N), which will ideally be recycled as an organic fertiliser. However, significant amounts of C and N are lost from litter before its removal from animal housing, resulting in the forfeiture of agronomically valuable nutrients and potentially leading to adverse environmental impacts. Additionally, odour from broiler farms can cause further issues, particularly regarding nuisance to surrounding communities. The encroachment of urban development into areas traditionally used for agriculture has reduced the spatial buffer between sources of odour and residents, often leading to conflict. These highlight the need for innovative and cost-effective technologies aimed at reducing C and N loss and abating odour emissions from broiler farms. The primary pathway of N loss from litter is the volatilisation of gaseous ammonia (NH3), a reactive form of N, which is produced as microbes hydrolyse uric acid in bird excreta. Likewise, the microbial decomposition of organic matter is the primary source of odour from litter. The rate at which these emissions occur is dictated by several in-house factors, including litter moisture, pH, temperature and ventilation. Lignite, which is a brown coal that is abundant in Victoria, has previously been shown to reduce NH3 emissions when applied to bedding in beef cattle feedlots and broiler litter in a laboratory incubation. However, its effectiveness in reducing NH3 emissions and odour from commercial broiler housing was unknown. This thesis investigated the capacity of lignite to reduce N loss and odour emissions from litter in commercial broiler housing and aims to improve the understanding of mechanisms by which any reductions occur. To investigate lignite's effect on N loss, it was applied to litter at a commercial broiler farm in Victoria, Australia, at a rate of 3.5 kg/m2 over three consecutive summer grow-out cycles. Lignite-treated litter retained more biomass, resulting in 32.1% more C and 45.8% more N per m2 than the untreated control. This was equivalent to an extra 70.1 g of C and 12.6 g of N per bird placed. Notably, lignite also reduced CO2 flux (microbial activity) in the litter by 46% at the end of the study. This reduction in microbial activity likely slowed litter decomposition, which contributed to the observed retention of C and N. Additionally, lignite consistently lowered litter moisture content by 3-7% and reduced litter water activity (Aw) to levels that were expected to inhibit microbial function. These results showed lignite's efficacy as a litter amendment, which enhanced litter nutrient value and reduced CO2 emissions. The main source of odour from broiler litter is the microbial decomposition of organic material. Thus, a reduction in microbial activity was expected to reduce odour emissions from broiler housing. A second experiment investigated the effect of lignite on odour emission rate (ou/s) using dynamic olfactometry over two consecutive summer grow-out cycles in Victoria, Australia, with lignite applied at the same rate as the previous experiment. The air quality dispersion model, AERMOD, was used to investigate how lignite’s effect on odour emission rate influenced the predicted odour dispersion distance and concentration in the context of the Australian regulatory framework. Additionally, the effect of lignite on bird production performance was also determined. This study showed that lignite reduced the odour emission rate from commercial broiler housing by an average of 55.5% over both grow-outs. This effect was observed for the duration of the trial, with maximal reductions of 54.9 and 71.3% per 1000 birds placed in week 7 for grow-out 1 and 2, respectively. Victorian EPA modelling requirements of a 3-minute averaging time and the 99.9th percentile provided a reduction in the total area under the 5 ou contour of 65.8%. There was no observed differences in feed conversion ratio, bird live weight or mortality throughout either grow-out. This study demonstrated the capacity of lignite to reduce odour emissions from commercial broiler housing without reducing bird production performance In a third experiment, custom tunnel ventilated chambers were used to simulate summer and winter conditions to assess the impact of lignite on water evaporation rates and the relationship between Aw and CO2 flux as a function of litter moisture content. The litter used was collected weekly over four weeks from two commercial broiler sheds, one treated with 3.5 kg/m2 lignite and the other left untreated. Under summer conditions (50% RH), lignite increased the evaporation rate by 0.06 L/m2/day for each 1% rise in moisture content (above 20% MC) at high ventilation (2.0 m/s), and by 0.03 L/m2/day at low ventilation. Under winter conditions (80% RH), the rates were 0.02 L/m2/day and 0.03 L/m2/day (above 15% MC) for high and low ventilation, respectively. Lignite-treated litter had a Aw of 0.90 at 25% moisture from week 4 of a grow-out compared to 0.95 in the control (while still being compared at 25% moisture content). This increased to 0.81 and 0.92 by week 7 for lignite and the control, respectively. Litter used in this study demonstrated a parabolic relationship with CO2 flux, with peak microbial activity consistently around 40% moisture content. However, from week 5 onwards, lignite-treated litter consistently reduced CO2 flux at all moisture levels, indicating lignite’s role in reducing microbial activity is independent of moisture content. Finally, an acid trap incubation experiment was conducted to assess the influence of lignite's physical and chemical properties on N transformations in litter, focusing on the effects of low Aw, humic acids, and lignite's surface area. Potassium chloride (KCl) was used to lower the Aw of litter (Aw 0.81) at a 40% moisture content where lignite had no effect on Aw (Aw 0.99). The KCl treatment reduced NH3 emissions by 78.1% compared to the control, whereas lignite resulted in an 83.4% reduction. In a second acid trap incubation, the effect of humic acids on N transformations were assessed. Similarly, at 40% moisture content, lignite reduced NH3 emissions by 61.8%, where the humic acid treatment reduced emissions by 89.2%, relative to the control. Lignite consistently increased ammonium-N (NH4-N) concentration, suggesting enhanced adsorption processes, in contrast to humic acid and K-Humate treatments increased urea levels, likely through inhibition of the urease enzyme. Conversely, the KCl treatments reduced microbial activity by lowering Aw, potentially restricting the hydrolysis of uric acid and thereby reducing N availability for further transformation. These findings indicate that lignite's capacity to mitigate N loss from broiler litter involves multiple mechanisms which contribute to its sustained efficacy. This thesis established that lignite effectively reduced N loss and odour from broiler litter under commercial conditions, primarily through the reduction of microbial activity. This reduction slowed down litter decomposition, which improves nutrient retention and reduces odour generation. Importantly, lignite's application did not impact bird production performance, including feed conversion ratio (FCR), live weight, or mortality. The effectiveness of lignite is linked to its physical and chemical properties, such as surface area, humic acid content, and the ability to lower litter Aw. These properties work in synergy to impact different forms of N, providing lignite with the sustained efficacy observed in this study (one month). This demonstrated lignite’s potential as an effective litter amendment for improved sustainability in commercial broiler housing.
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ItemNo Preview AvailableAbsolute Poverty and Human Rights: An Examination of Factual and Normative Issues surrounding Absolute World Poverty( 2023-11)In this thesis, I aim to explore factual and normative questions surrounding the problem of world poverty. In chapter 1, I ask the following questions: What is absolute poverty? What is the extent of absolute poverty? And what are the kinds of causes responsible for generating and sustaining poverty in the world? I define absolute poverty as material deprivation such that the individual lacks adequate access to the means of survival. These include lack of adequate drinking water, food, clothing, access to essential medical assistance, and shelter (adequate housing, in modern societies). I will now give an overview of each chapter in the thesis. In recent times, it has been popular among scholars to claim (1) that there is a negative duty not to benefit from injustice and that (2) this can be the basis of claiming that since the people and governments in western countries are harming the poor in some way, that therefore they must stop doing what is causing such harm and remedy the situation. The claim then consists of a theoretical question, that is, whether or not there is such a general duty of the kind that is claimed to exist; and the empirical claim that in fact the people and governments in western countries are implicated in harms that the world’s poor suffer from. Therefore, in chapters 2-3 I ask whether or not there is a general moral duty not to benefit from an injustice done by others. I argue that there is no such duty. But there is a duty not to harm others, which can give rise to a demand not to benefit from injustice on particular occasions, should other conditions also be met, which conditions I highlight in chapter 2. Chapter 3 is related to the negative thesis (denial of the claim presented that such a duty exists) of chapter 2, but also points out that claims of compensation for historical wrongs committed against peoples who may be appropriately linked to current victims is unlikely to be supported by sufficient evidence. Chapter 4 takes a look at relative poverty, or poverty relative to national standards, and draws on Rawlsian theory of primary social goods to argue that due to the nature of the work that many poor people are compelled (by lack of options) to do, they are greatly disadvantaged from gaining adequate amounts of essential goods such as self-respect, at least from their work, which is an important source of self-esteem in many people’s lives. In relation to the overall thesis, I point out that due to the role money plays in many societies in the world, that the link between possessing wealth and income of a certain degree has great impact on people’s self-esteem and also on their social status. In chapter 5, I present a case for the existence of a positive human right to be free from absolute poverty, which entails secure access to minimal material provisions. There I contrast different conceptions of human rights (Pogge’s institutionalist conception, Joseph Raz’s functionalist account, and James Griffin’s personhood account) and argue that using Rawls’s idea of reflective equilibrium we can reach a more or less coherent set of human rights one of which includes the right to be free from poverty of the kind that afflicts about half the world’s population. In chapter 5, I explore the institutionalist account by Pogge and point out some ways that institutions can be said to play an important role in realising human rights for all. Chapter 6 considers the impact of some global institutions such as the International Monetary Fund (IMF, for short) on exacerbating the condition of the poor. I also argue that understanding the story of how poverty has decreased over time requires our taking into account non-global developments such as China’s efforts in the 20th century to urbanise and reduce poverty in their country, but also reduction of poverty in parts of south-east Asia which were accelerated by their joining the World Trade Organisation (WTO) but which also had non-global components and preceded the creation of the WTO. I examine a thesis advanced by Thomas Pogge called the Feasible Alternative Thesis (FAT for short) and argue that for our global institutions to be just, we must ensure that the only human rights deficits that exist are those which fall outside the control of our institutions and which thus cannot be either reasonably avoided or foreseen (or both). This implies that our global institutions, such as the World Bank, and World Trade Organisation are unjust and harmful to the poor if they allow human rights deficits (e.g. lack of adequate material goods for people on whom this global order is imposed) to occur which these institutions could foresee and reasonably prevent. Let us begin with settling some factual questions concerning the nature of poverty and the kinds of causes which generate it (chapter 1) before taking a look at some related normative questions in chapter 2.
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ItemWheat grain protein content assessment via plant traits retrieved from airborne hyperspectral and satellite remote sensing imagery( 2023-11)Wheat (Triticum spp.) is crucial to food security. The source of a major proportion of humans’ total dietary carbohydrates and protein, it is among the world’s most widely grown crops and receives concomitantly large quantities of nitrogen (N) fertiliser. Wheat grain protein content (GPC; %) is a key to food quality, determining the baking quality of bread, the cooking quality of pasta, and the nutritional value of food products. For these reasons, wheat is classified and growers are typically paid predominantly on the basis of GPC, setting its farm income value. Global population growth encourages a justified focus on increasing yields. However, because grain proteins are diluted by carbohydrate (CHO) additions in the latter part of growing seasons, GPC is in an inverse relationship with yield: Improved yields are attended by the risk of reducing GPC. Moreover, GPC is influenced by interacting genetic and agronomic factors, soil properties and weather conditions that affect crops’ physiological status and stress levels and can therefore exhibit great spatial variability. Of the vast quantities of nitrogen (N) applied to wheat crops, a variable but substantial proportion is lost, inducing environmental damage and financial costs, which should be averted. Accurate GPC prediction could reduce N losses, assist in crop management decisions, and improve farm incomes. Nitrogen is central to proteins and can be strategically supplied to crops in order to achieve GPC benchmarks a precision agriculture (PA) approach. In such scenarios, estimates of GPC potential in advance of harvest could guide fertiliser dosing, improving fertiliser efficiency and potentially reducing costs. In contrast, where strategic fertiliser applications are not favoured, crop management could benefit from prior knowledge through strategic harvesting aimed at maximising payments per unit of grain at receival. However, GPC is a complex variable, influenced by multiple plant traits, themselves affected by soil and moisture conditions and whose effects change through the growing season. While remote sensing (RS) is likely the only practicable method of estimating GPC during seasons, and shows potential, prediction is complex and success has been limited. To make progress, it is necessary to more robustly identify imaging spectroscopy-based physiological traits closely associated with GPC. Traits with known physiological links to GPC, and which can be retrieved from imaging spectroscopy, include leaf area index (LAI) and chlorophyll (Ca+b). Further inspection of these and other RS traits may advance research relevant to PA. The inverse relationship of GPC to CHO assimilation permits the hypothesis that indicators of plant stress can improve GPC estimation. Such stress indicators, including the pigments anthocyanins and carotenoids, can be accurately retrieved along with other biophysical and biochemical quantities from hyperspectral (HS) remote sensing but their relationship to GPC had yet to be tested. Solar-induced fluorescence (SIF), emitted from the photosystems in proportion to instantaneous photosynthetic rate, was also untested as a GPC predictor. Moreover, in addition to the traits themselves, retrieval of plant traits by inversion of radiative transfer models (RTM) also remained untried for GPC estimation. Finally, the crop water stress indicator (CWSI), a proxy for evapotranspiration and hence carbon assimilation, should also show an association with GPC. Because a large majority of GPC studies have been conducted exclusively in the context of experimental plots, it is appropriate to extend research into the commercial cropping domain, populated to date by only two previous studies. This expansion is facilitated by the recent advent of spatially explicit GPC monitoring during crop harvests. While lacking the ultra-high spectral and spatial resolution of airborne HS sensing, satellite RS, in particular the Sentinel-2 (S2) platforms, possess advantages with respect to broadacre PA. These include a focus on reflectance bands adapted to vegetation sensing, appropriate spatial resolution, and frequent return times. This thesis presents results from piloted HS flights and ground campaigns at two dryland field experiments with divergent water supply and wide-ranging N fertiliser treatments, and from HS flights over 17 commercial fields planted to either bread (T. aestivum L.) or durum (T. turgidum subsp. durum (Desf.) Husn.) wheat, across two years in the southern Australian wheat belt. Imagery was acquired with airborne hyperspectral and thermal sensors, with spatial resolutions of approx. 0.3 m and 0.5 m for experimental plots and 1 m / 1.7 m in commercial fields. Leaf clip measurements, leaf and grain samples were collected from plots and through a transect in one field. In commercial fields, ~40,000 records obtained from harvester-mounted protein monitors. CWSI, SIF, vegetation indices and PRO4SAIL RTM inverted parameters were retrieved for each plot and GPC record location. Sentinel-2 (S2) timeseries (TS) were subsequently acquired for > 6,000 ha of commercial dryland wheat fields, inclusive of those included in HS campaigns, also in south-east Australia and through two consecutive years of dissimilar rainfall. In this case, growers provided ~92,000 GPC data points from harvester-mounted protein monitors. For each, Ca+b, leaf dry matter, leaf water content (Cw) and LAI were retrieved from the S2 images by radiative transfer model inversion. A gradient boosted machine learning algorithm was applied to analyse these traits’ importance to GPC and to predict GPC in 30% of samples unseen by the algorithm in training. From HS analyses, the photochemical reflectance index (PRI) related to xanthophyll pigments was consistently associated with GPC at both leaf and canopy scale in the plots and transect. In the commercial crops, a gradient boosted machine learning algorithm (GBM) ranked CWSI as the strongest indicator of GPC under severe water stress, while SIF, PRI and inverted biochemical constituents anthocyanins and carotenoids were consistently important under more moderate growing conditions. Structural parameters inverted from HS were not prominent except under severe drought when CWSI was omitted from models. Statistically significant results were obtained for GPC estimation in unseen samples, with best relationships between predicted and observed GPC of R2 = 0.80 and RMSE = 0.62 in a model built with thermal and physiological traits obtained from the HS and thermal imagery. Trait importance in S2 analyses was consistent with that seen from HS, in that the rankings of physiological, structural and water stress indicators were aligned: severe drought increased the importance of water stress measures relative to other traits, but in milder conditions physiological traits were emphasised. Airborne SIF added substantially to model skill from single-image S2, particularly in moderate conditions. While coefficients of determination varied substantially according to water stress, error metrics invariably sat within a tight range, under 1 % GPC. Overall, these predictive modelling results, obtained at within-field scale and in challenging conditions, place the current study among others in the same research domain, most of which consider either plot or regional scales. The strongest relationships between predicted and observed GPC (R2 = 0.86, RMSE = 0.56 %), in a model built from five S2 images across a season, were better than those from single-date hyperspectral (HS). In severe water stress, LAI was the main predictor of GPC early in the season, but this switched to Cw later. In milder conditions, importance was more evenly distributed both through the years and between traits, and predictive skill was lower. S2 TS had a clear accuracy advantage over single-date S2, and approached that of HS, especially in benign conditions, emphasising its previously unexplored potential for large-scale GPC monitoring. The methods developed are a novel contribution and can be proposed as a useful basis for future research.
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ItemEnzyme-responsive nanomaterials for the delivery of antimicrobial peptides( 2023-10)The rate of resistance to antibiotics that are commonly used in the clinic is escalating rapidly, surpassing the introduction of new antimicrobial drugs. To address this problem, alternative strategies are being explored, such as the re-evaluation of antibiotics, that have not yet gained widespread clinical application. Antimicrobial peptides (AMPs) represent one of those antibiotics, offering remarkable antimicrobial efficacy against various pathogens. However, in clinical settings, AMPs are typically considered a last-resort option due to their off-target effects and poor stability in-vivo resulting from their cationic and amphiphilic peptide nature. Therefore, most of current strategies addressing these limitations focus primarily on the control and shielding of the cationic charge and the amphiphilic nature of AMPs. These can potentially be achieved through encapsulation of AMPs inside stimuli-responsive polyelectrolyte complexes (PECs) by combining the cationic drug with anionic polyelectrolytes. Stimuli-responsive polymers can be employed as encapsulation materials in PECs to design systems that activate drug release in response to specific changes encountered during microbial infection, such as variations in pH, enzyme activity, or temperature. The overarching aim of this Thesis was to explore the creation of PECs capable of encapsulating the clinically approved antimicrobial peptide, Polymyxin B and its subsequent enzyme-induced release. In Chapters 2 and 3, the aims were: Firstly, to synthesize anionic and helical polymers incorporating enzyme-degradable peptide side chains (Aim 1.1), followed by evaluation of the degradation properties of these polymers in response to the enzyme released by gram-negative bacterium Pseudomonas aeruginosa (Aim 1.2). In Chapter 4, the first objective (Aim 1.3) was to assemble Polymyxin B and the anionic enzyme-degradable polymers into PECs. The next objective (Aim 1.4 ) involved investigating the P. aeruginosa-induced drug release from these PECs, while Aim 1.5 focused on assessing the antimicrobial activity of the developed PECs against P. aeruginosa strains. Chapter 1 provides a review of the current developments in the field of the stimuli- responsive delivery of AMPs using polyelectrolyte complexes. Chapters 2 and 3 discuss the synthesis of polymers with poly(methacrylamide) and poly(acetylene) backbones respectively coupled to enzyme-degradable peptide side chains. Of the synthesized materials, two poly(methacrylamide) polymers from Chapter 2 were found to be the most effective in terms of degradation by the enzyme released by P.aeruginosa, while none of the synthesized acetylene-containing peptides from Chapter 3 polymerized. Subsequently, the poly(methacrylamide) polymer with the highest multivalency was used to form PECs with Polymyxin B in Chapter 4. Eight different formulations of PECs were created, with one being the most optimized in terms of encapsulation efficacy and physiological stability. The stability of the particles was further improved by the addition of Tannic Acid, which acted as a protective coating and a cross-linker. The Thesis then evaluated the ability of the PECs to release Polymyxin B under enzymatic degradation. Finally, the preliminary evaluation of the antimicrobial activity of the PECs against various P.aeruginosa strains were presented.
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ItemAutonomous Resource Management for Serverless Computing( 2023-11)Serverless computing is gaining momentum as the latest cloud deployment model for applications, with many major global companies shifting towards a complete adoption of this new computing paradigm. As the name implies, the burden of server management is non-existent to the end user under this model, with the cloud vendor taking full responsibility of infrastructure management. The users simply deploy the logic of their application in the form of code segments called 'functions', with a rough estimate on the resource requirements and the rest is taken care of by the serverless platform. This greatly reduces the time-to-market and upfront costs for client products with no expertise required in initial server configurations and subsequent operations. The rapid auto-scalability feature allows customers to scale their businesses fast, without the need for any prior infrastructure requirement planning. The pay-per-use billing model enables a fair ground for applications with spontaneous fluctuations in traffic loads. However, the 'serverless' nature to the end user unequivocally leaves the entire set of end to end server management responsibilities with the cloud vendor. In contrast to conventional Infrastructure-as-a-Service (IaaS) cloud model, where the provider only handles the physical infrastructure maintenance, now the complete virtual machine maintenance is also part of the provider service offering. Moreover, unlike the users managing their allocated resources for the execution of their own applications, the cloud provider has to undertake the same set of tasks with far lesser knowledge available to them. Not only do they have to successfully manage the infrastructure for an application belonging to a separate party, but they need to accommodate the needs of thousands of user applications on the same shared platform, considering the impact of their co-resident behaviors as well. Thus this is a tremendous feat for cloud vendors if accomplished to the satisfaction of all the parties involved. Further, while auto-scaling and granular billing features are vastly favorable to end users, the cloud vendors are at a grave disadvantage if measures are not taken to maintain high efficiency in their underlying resources. Hence, having proper techniques for resource management in place which are capable of meeting all of these challenges is of utmost importance. The existing commercial and open-source serverless platforms mostly follow primitive resource management policies at the moment, which have a vast potential to be optimized. Further, although there is a huge interest in the research community in this area of study, most of the existing works are limited in their generalizability to be adaptable to practical serverless computing environments, considering the multi-tenant and rapidly changing nature of these systems. Moreover, a vast majority of these works are negligent on the service provider perspective of their offered solutions, which is a key factor determining the probable adoption of the same in vendor platforms. This thesis investigates novel techniques for the smooth running of all resource handling operations including resource provisioning, resource scheduling and scaling, which are dynamic and intelligent enough to handle the complexities of this computing environment. Proposed approaches strive to gain a thorough understanding on the behavior of the serverless computing infrastructure, along with the different application workloads, in developing strategies beneficial for both end users and cloud vendors. In essence, this thesis advances the state-of-the-art by making the following contributions: - A comprehensive taxonomy and literature review on the aspect of resource management in serverless computing environments, along with a discussion on identified research gaps, laying the ground work for future research work. - A dynamic resource management and a function request placement technique for meeting user specific application requirements and maintaining high resource efficiency. - A Deep Reinforcement Learning (DRL) based workload and system aware technique for scheduling applications in resource-constrained, multi-tenant serverless computing environments, along with flexibility in achieving a desirable level of application performance and resource cost optimization. - A framework for horizontally and vertically scaling allocated resources to function instances based on a multi-agent DRL model for elevating application performance while maintaining provider resource cost efficiency. - A deployment and scheduling approach for applications in a hybrid serverless and serverful environment based on DRL, with the aim of reducing application latency and incurred user cost. - A detailed discussion outlining challenges and the potential for future work for the efficient use of serverless computing environments.
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ItemExploring the Outlands: A Case-Study on the Conservation Installation and Artist Interview of David Haines’ and Joyce Hinterding’s Time-Based Art Installation(Taylor and Francis Group, 2021)The artwork by David Haines and Joyce Hinterding, The outlands, 2011 is a time-based art installation composed of sculptural, software and gaming technology exhibited in a gallery space. The work was acquired by the Art Gallery of New South Wales after being awarded the 2011 Anne Landa Award Unguided Tours exhibition prize but has not been installed since. As such, any future iterations will be challenging due to its condition, functionality and machine dependency. This paper explores the value of installing Haines’ and Hinterding’s time-based art installation to chart the conservation assessment processes of documentation, functionality testing and the install itself. It discusses how in-situ artist interview affords artistic agency and contributes knowledge on the materials, conceptual and technical elements of the work, functional limitations and its future conservation management. The outcomes of the conservation interactions have allowed for a deeper understanding of conservation as a reiterative process as issues of software and hardware dependencies, and the situated and spatial relationships between various elements became more salient. This has assisted conservators in preparing for object obsolescence and aims to support future re-activations of The outlands, 2011.
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ItemTriplex forming oligonucleotides to silence the HIV reservoir( 2023-10)The eradication of HIV remains a formidable challenge due to the virus's ability to establish latent reservoirs within host cells, evading antiretroviral therapy (ART). The overarching objective of this thesis was to evaluate the potential of Triplex-Forming Oligonucleotides (TFOs) as an innovative approach to inhibit HIV transcription from latency and to ascertain efficient nuclear delivery mechanisms, thereby contributing to the 'Block and Lock' strategy aimed at maintaining viral suppression without continuous ART. Our seminal findings underscore the ability of TFOs to inhibit HIV transcription, as evidenced in models such as the HEK 293T plasmid transfection and a latently infected cell line. However, challenges including limited nuclear penetration and potential binding impediments due to chromatin structure were observed. Encouragingly, encapsulation of TFOs within lipid nanoparticles demonstrated a moderate reduction in HIV transcription in the latently infected cell line, albeit optimization in delivery and stability being imperative. Distinct from previous studies targeting the LTR region, our investigation expanded to TFOs targeting the HIV gag, envelope, and pol genes, unveiling a high degree of conservation in target sequences, and thus broadening the target range of TFOs. This novel approach substantiates that non-LTR targeting TFOs can also significantly inhibit HIV virion production in vitro, offering a promising avenue to overcome the variability challenges associated with LTR region targeting employed by other gene modification tools. Despite the encouraging in vitro outcomes, the study acknowledges inherent limitations predominantly centered around the in vitro nature of the experiments and the need for further optimization in TFO delivery. Our work explored two nanoparticle formulations, gold nanoparticles and lipid nanoparticles, for their potential in conveying TFOs to target cells. Particularly, lipid nanoparticles emerged as a promising candidate for delivering 'Block and Lock' strategies, inspired by their recent success in mRNA COVID-19 vaccine technology. Through a systematic investigation, this thesis delineates a promising pathway towards HIV transcriptional inhibition using TFOs and underscores the significance of optimizing nanoparticle-mediated TFO delivery. The insights garnered from this work lay a robust foundation for future in vivo and clinical investigations, steering closer towards the long-term goal of an cure for HIV.