15234 research outputs found
Sort by
Analysis, Prediction and Mitigation of Nonlinearity-induced Spurs and Noise in Fractional-N Frequency Synthesizers
No full textFractional-N frequency synthesizers are commonly used in communication systems. A divider controller is employed within a conventional divider-based fractional-N frequency synthesizer to achieve the desired fractional division ratio. A MultistAge Noise SHaping (MASH) Digital Delta-Sigma Modulator (DDSM) is usually used as the divider controller because of its high-pass shaped quantization error and ease of implementation. Among contributors to the output phase noise of a conventional fractional-N frequency synthesizer, the noise of the divider controller is normally high-pass shaped and its in-band contribution can be ignored under the assumption of linearity. In the presence of nonlinearity, however, the phase noise contribution of the divider controller becomes prominent in-band, denoted folded noise, and spurious tones usually appear. The causes of divider controller-induced spurious tones in the long-term spectrum have been the focus of research for many years and efforts continue to be made to identify and mitigate nonlinearity-induced spurs in synthesizers. In this thesis, we analyze the generation of nonlinearity-induced folded noise in fractional-N frequency synthesizers with MASH-based divider controllers and an accurate prediction method is described. The phenomena of spur immunity and sub-fractional spurious tones, called "horn spurs", are analyzed in MASH modulators. A family of DDSMs is introduced that allows one to achieve enhanced performance in terms of nonlinearity-induced noise. The so-called ENOP DDSMs are provably spur free in the presence of static polynomial nonlinearities of a specified order. Moreover, another family of DDSMs is introduced whose quantization error is inherently immune from spurs when interacting with a static nonlinearity. The so-called INIS-DDSMs are suitable for digital to analog transduction, such as for DCO controllers
Oracle Child: The Figure of the Child and the Role of Autobiographical Childhood Memory in the Poetry of Seamus Heaney
No full textThis thesis explores childhood memory in the lyric poetry of Seamus Heaney, examining how the figure of the autobiographical child in his work facilitates a comprehensive curation of the self as subject – the revelation of the self to the self as it evolves from early childhood to old age – with a particular focus on Heaney’s evolving understanding of his own vocation as a poet. Heaney’s self-reflexive use of childhood memory is further read as being highly attuned both to the changing circumstances of the adult’s personal life, and to the shifting socio-political contexts of his poetry’s time of writing. This thesis argues that the continuous raids on the early remembered life represented in the poetry are the result of Heaney’s sense of his own life-stages’ binding connectedness. The moments of poetry as a “revelation of the self to the self” (Heaney, P, 41) are in lock-step with the moments of self-awareness and epiphany in childhood, Heaney’s adult discoveries at once summoning and being reflected in the remembered moments of awareness of self in childhood. As represented in his poetry, these revelations suggest a preternatural predilection for poetic perception in childhood, acknowledged as source by Heaney in adulthood and continuously and assiduously mined by the poet. Childhood, therefore, is indicated to be the source and recourse for much of Heaney’s poetry and inheres as such from the first volume to the last. Accordingly, childhood memory is explored in this thesis through a chronological analysis of Heaney’s published volumes of poetry from Death of a Naturalist (1966) through to Human Chain (2010). Throughout, Heaney unequivocally links the poet’s adult creative meditations with the apprehending of his own child-poet self – ‘poet’ in the sense of one who experiences transformative perceptions of the given – a figure who shall be referred to in this thesis as the Oracle Child
Towards Communion: Encountering a Life in Brian Friel's "Faith Healer"
No full textBrian Friel’s Faith Healer makes a problem of connection. It does not merely ‘represent’ the problem of connection for our contemplation: it stages it, and implicates us in it, undermining the very ground of our contemplation. For not only do the play’s three characters, across their extended monologues, describe their fraught relationships with one another, but their accounts of their supposedly shared life diverge from each other wildly. Coupled with the absence of any dialogue or neutral viewpoint, this disables any interpretative attempt to determine, non-arbitrarily, the connection between its characters’ statements and ‘what’ they represent. Interpreters of Faith Healer have attempted to solve this problem in two principal ways: by seeking to uncover ‘what’ the characters represent, or by seeking to determine the internal structures of their representations. But without any glimpse at ‘what’ the characters represent, both rest ultimately upon arbitrary assumptions. Abandoning this untenable assumption of fundamental mimeticism, this project seeks not to solve the problem of Faith Healer’s non-coherence, but to affirm it. It argues that the three characters’ determinations are not representations needing interpretative judgement, but creative expressions of the three lives that take place in the present of the reading/viewing encounter. The aim, here, is not to ‘make sense’ of the text as a whole, but to affirmatively engage the present sense-making of these different lives with trust and rigour. Chapter 1 of this project works through the critical literature, laying down the conditions for such an affirmative encounter. Chapter 2 articulates the basic concepts that the text creates, while chapters 3 through 5 seek to explore the complex and dynamic systems of living of each its characters. Chapter 6, exploring the repetitions that proliferate between the monologues, argues that Faith Healer is a work that is without overall unity, but composed of an intricate network of local connections created in the reading/viewing encounter
Sustainability versus Viability in Increased Residential Density: Examining the Implementation of Compact City Policies in Ireland
No full textThe period from 2018 to 2023 reflects a major inflection point in the evolution of planning policy in Ireland. During this period, government planning policies related to compact growth, housing densities, strategic planning and sustainability goals have become highly centralised. A conflation of housing needs and sustainability goals have led to an increased role for higher residential densities and apartment development as a preferred policy approach. To facilitate higher densities, a 'fast track' planning system and reduced design standards were used to boost development viability. Reforms in the construction supply and procurement processes including broader urban land use policies have been relatively neglected in favour of these approaches. This research analyses the processes of policy formulation and implementation involved in this shift. A core issue is evaluating whether such policies address either the housing crisis or the sustainability goals they were intended to address. The research also examines the policy direction, influences and pressures involved including the role of industry interests and other perspectives. The research employs a combination of quantitative and qualitative research methods, including a policy review, residential data profiling, semi-structured interviews and analysis of data on increased residential developments under those compact city policies.2025-12-03 JG: Author's signature removed from PD
Hidden Wounds: Exploring the Psychosocial Impact of Hidradenitis Suppurativa
No full textBackground: Hidradenitis Suppurativa (HS) is a chronic inflammatory skin disorder that has been demonstrated to have a profound impact on psychosocial functioning. Furthermore, those with HS have been shown to have significantly higher rates of mental health difficulties than those with other dermatoses, due to its high symptom burden and the stigma associated with the condition. Despite the breadth and magnitude of the deleterious effects of HS on psychological, physical, and social well-being, limited research has been conducted with the population exploring the impacts of HS on psychosocial well-being and functioning. There also appears to be a particular dearth of evidence that examines the psychological processes that predict these impairments in quality of life. Aims: This thesis aims to further understand and explore the psychosocial burden of HS. Specifically, this thesis looks to understand the impact of stigma and its relationship with psychosocial outcomes that have been identified as central to the lived experience of HS. This thesis also aims to identify modifiable psychological factors that may be implicated in the maintenance of psychological distress and impaired quality of life in those suffering with HS. Methods: Regarding these aims, a systematic narrative review was conducted to explore the extant literature related to experiences of stigma in HS. Second, an empirical investigation into the mediating roles of stigma, shame, and self-compassion, between depression, anxiety, and quality of life was conducted. Results: The systematic review revealed that enacted, perceived, and self-stigma are central to the experience of living with HS. The review also highlighted the profound impact stigma plays in disruptions to psychological, social, and physical well-being, and perhaps most importantly, the role it plays in impeding care seeking and health-care engagement. With regard to the empirical study, significant positive associations were found between depression, anxiety, quality of life, stigma, and shame, with self-compassion being significantly negatively associated with these psychosocial factors. Results partially confirmed the model, with depression, anxiety, stigma, shame, and self-compassion contributing to a considerable amount of variance (41%) in QoL. Depression was a positive predictor of impaired quality of life, while stigma, shame, and self-compassion were joint and unique mediators of this relationship. However, anxiety was not found to be a significant direct or indirect predictor of quality of life in the proposed model. Conclusion: Findings support that living with HS involves a substantial psychosocial burden, shaped by the complex interplay between disease-related factors, psychological distress, stigma, and impaired quality of life. Underscoring the importance of addressing the psychological and social dimensions of HS as core components of effective treatment and support.2025-10-29 JG: Author's signature removed from PD
Development and validation of the of a State-based Wellbeing Scale to Evaluate the "A Lust for Life Schools Programme"
No full textThe increasing prevalence of mental health difficulties in children and adolescents highlights the significant need to promote positive mental health and wellbeing in youth. Schools are uniquely positioned to provide universal interventions that foster resilience, coping skills and wellbeing. However, capturing the effectiveness of such programmes relies on the use of valid, contextually appropriate psychometric scales. The research presented in this thesis is aimed to explore the scales used to measure wellbeing in school-based positive psychology interventions (PPIs), and to develop a psychometrically valid, child-centred scale of state-wellbeing. Accordingly, a systematic review of six systematic reviews and meta-analyses revealed a lack of state-based wellbeing psychometric scales used in school-based wellbeing, mindfulness, and PPI research. The review recommended a list of scales and highlighted the need to align the intervention goal with the evaluation methods. Building on these findings, the empirical research of this thesis involved the development and validation of the Feeling Better Scale (FBS) - a novel, state-based self-report scale designed for use with children aged 8-13 following participation in the A Lust for Life (ALFL) Schools Programme. The FBS was created through a multi-stage, mixed-methods process including focus groups and psychometric assessments. The central findings of the study were that a 23-item, 2-factor version of the FBS best fit the data and demonstrated good internal consistency, construct validity, and responsiveness to change. Collectively, these findings support the development of child-informed, state-sensitive scales for more accurate and meaningful programme evaluations of PPIs and provide a number of implications for practice
Reprogramming T cell Metabolism: A New Approach for HIV Cure
No full textDespite the success of Antiretroviral therapy (ART), HIV-1 persists transcriptionally silent yet replication-competent cellular reservoirs, facilitating viral rebound upon treatment interruption. In these latent reservoirs, HIV-1 gene silencing is mediated by multiple mechanisms, including epigenetic silencing, transcriptional, post-transcriptional and translational blocks, along with a quiescent metabolism. The Shock & Kill strategy, part of HIV CURE research, aims to reactivate HIV-1 from latency by targeting these blocks and eliminating infected cells via immune-mediated clearance or viral cytopathic effects.
Recent evidence indicates that HIV-1 infection, gene expression and the establishment of latent reservoirs are linked to cellular metabolic activities. However, targeting the cellular metabolism to reverse HIV-1 from latency remains largely unexplored. This PhD thesis evaluates Zaprinast, a Mitochondrial Pyruvate Carrier inhibitor (MPCi), for its capacity to reverse HIV latency in viral reservoirs using two ex vivo latency assays with primary immune cells isolated from ART-suppressed People Living with HIV-1. Zaprinast successfully induced viral gene transcription in 50% of the cases using ex vivo latency assays with primary CD4+ T cells, achieving 75% of maximal HIV reactivation compared to global T cell stimulation. Additionally, Zaprinast facilitated efficient viral release in 64% of samples using CD8+ T-deplected PBMCs, inducing viral production at 69% compared to maximal reactivation by TCR activation. Importantly, Zaprinast treatment did not induce cytotoxicity, T cell activation or proliferation, or ROS production. Additionally, Zaprinast reprogrammed the quiescent metabolism of resting CD4+ T cells, increasing aerobic glycolysis and mitochondrial respiration leading to enhanced ATP production. This findings demonstrate that MPCi represent a potent new class of LRAs capable of inducing robust HIV-1 latency reversal from circulating viral reservoirs ex vivo. This stronly support the potential of targeting the quiescent metabolism of CD4+ T cells as a promising appraoch for HIV cure research
Development and Validation of Test Methods for Hydroxyapatite Coatings for Commercial Use
No full textThis thesis develops and validates test methods to test critical to quality factors of the hydroxyapatite coated parts from the internal HA line. The aim is to develop robust and reliable test methods for process monitoring and internal testing. The properties in focus were crystallinity, coating adhesion, thickness, porosity, rate of corundum incrustation and calcium phosphate testing. This thesis was conducted in collaboration with DePuy Synthes. HA powder is removed from the Ti6Al4V coupons using a Diprofil reciprocating file which uses a diamond tool. The scraped powder is sieved using a test sieve with a < 40 µm stainless steel mesh. Uniformity within the crystals allows a thorough investigation of all crystal phases within a powder sample. HA powder was analysed using a 0.5g sample holder. Six coupons are used to create one sample. The powder was scanned through a range of 20 °2ϴ to 55 °2ϴ. The X-Ray diffraction pattern was produced in the range corresponding to the peaks selected (peak 210 or peak 211 for apatite, peak 0.210 for β-tricalcium phosphate and peak 200 for calcium oxide). The integrated intensities of the peaks selected for the apatite and the β-tricalcium phosphate were measured. DSC was performed on the 3 batches of FM1000 glue. Samples were placed in between crimped aluminium pans and subjected to a pre-determined temperature profile which replicates that of the current curing process – heated from ambient temperature to 180°C at 2.5°C per minute and then held at 180°C for 2.5hrs. All samples were run in triplicate. The exothermic peaks were then analysed on all DSC traces and results recorded. The ability to analyse porosity is an essential critical to quality component, as porosity influences both the physical and mechanical characteristics of hydroxyapatite, with the rate of bone ingrowth and the rate of dissolution directly proportionate to the degree of porosity of the HA coating. Images were taken across a minimum area of 20 micron and 10 equally spaced perpendicular lines were generated across each field with the distance material measured as the coating thickness. The average of the individual coating thickness measurements from all the fields measured is then calculated as the mean coating thickness. Samples were placed face down on the stage, rate of corundum incrustation was measured using Leica application suite V4.12. Five areas of the sample were imaged using brightfield settings on the Leica DMI inverted microscope. Images are captured at 100x Magnification (10x objective) to allow for distinction between features. Images taken across a minimum of area of 20 µm were loaded into the software for analysis. The average rate of corundum incrustation across the five fields that are measured then calculated as the mean rate of corundum incrustation. The zone of indifference for this test was identified as 6.5%. The mean porosity of external testing was determined to be 1.5%. The mean porosity of internal testing was determined to be 0.35%. Thus, the difference in means is 1.05% which lies within the zone of indifference is compliant to the acceptance criteria outlined above. The P-Value is statistically significant and determines that all the acceptance requirements as outlined above. The Ca/P ratio specification/tolerance as outlined above is 1.67 to 1.76, all the samples run have calculated Ca/P ratios within this range.2025-11-11 JG: Author's signature removed from PD
Organised nanoscale architectures for biological regulation: Including surface property and shape
No full textNanoparticles (NPs) have been shown to have many potential applications in nanomedicine, to achieve such goals, NPs must play their role successfully after entering and accumulating in the desired cells without side effects. The physicochemical properties of the NPs, including size, surface properties, and shape, was regarded as the main features that influence their regulation in biological outcomes. Therefore, it is important to have a good understanding of the interactions between NPs and biological systems. The aim of this thesis was to study the influence of physiochemistry properties (mainly the composition, surface properties, and shape) of NPs on biological outcomes, such as cell-membrane recognition, immunology response, and in vivo distribution. Initially, fluorescent spherical silica NPs were synthesized by a modified Stöber method. The surface of the obtained NPs was aminated first, thus it can be PEGylated with a clickable group. The ApoE protein with a single chain was selected as the model for the surface functionalization, which can be grafted on NPs with controlled orientation by click chemistry. This strategy can also be successfully applied to silica-based core/shell structures, including the magnetic core and gold core nanostructures. Thanks to the merits of super magnetic core or gold core, this NPs-protein conjugation can be used for the study of the influence of grafted protein on biological regulation, such as cell-membrane recognition and biodistribution. Furthermore, fluorescent multi magnetic core silica shell and AuNP@SiO2NPs were fabricated using the Stöber method. Thanks to the super magnetic property of the magnetic core, it can be used for the study of the NPs trafficking pathways as it can be recovered after interacting with cells, which is useful for the design of nanomedicine with improved targeting efficiency. The use of single gold core can be used as a tool for the quantification of concentration by inductively coupled plasma mass spectrometry (ICP-MS). In the study of shape effects, a microfluidics method was used for the synthesis of gold NPs (GNP) with different shapes, the microfluidics method was promising in GNP synthesis due to the fine control over parameters, which gives high reproducibility and quality control. Shape identification and classification requires assiduous effort in chemistry synthesis, an II advanced computational contour analysis was applied to help isolate similar shapes from each other. With the help of this computational method, the shape distribution can be tuned through the changes of reactant. Therefore, four shapes with different populations were selected based on the contour analysis, thus the relationship between particle shape and their biological effects can be clearly investigated, such as the biodistribution and immunology. In summary, well-organized nanoscale architectures were synthesized and characterized, including different surface functionalization and shape, which can be used for the study of their biological regulation, such as cell membrane recognition, NPs trafficking pathway, and biodistributions
Essays in Sustainable Banking and Finance: Divestment, Engagement & Transition
No full textThis thesis is a compilation of three papers that study different aspects of sustainable banking & finance. Firstly, I assess how banks compromise to Socially Responsible Investment by analysing if they divest shares of banks found guilty of misconduct. In the second essay, I examine whether institutional investors can reduce their exposure to climate-change-induced systematic risk by privately engaging with their portfolio firms to solve environmental issues. In the final chapter, I ask whether investors use industry classification benchmarks as sustainability measures by analysing firms' performance after their code changes to a greener or a browner code. A growing group of institutional investors use divestment strategically to deter harmful misconduct to the climate and society. In Chapter 2, based on Kantian ethics, I propose that divestment represents investors' universal and absolute moral commitment to socially responsible investing (SRI). Following categorical and hypothetical imperatives and reciprocity as a norm, I hypothesize how institutional investors commit to SRI through a divestment strategy against ethically reprehensible behaviour of banks, especially when these investors represent banks themselves. Using a hand-collected database of the revelation dates of enforcement actions on banks, I find evidence that banks are less likely to divest equity holding on banks with misconduct (fined banks) than their non-bank institutional investor peers. Banks that commit to investing responsibly by signing for the Principles for Responsible Investment (PRI) are not significantly more likely to divest on fined banks stocks than non-signatory banks. Moreover, divestment of fined banks whose own legitimacy to operate is in question is not significantly different from non-fined banks' divestment. European banks are more inclined to sell their holdings permanently on fined banks than their United States peers. Therefore, bank's moral commitment to SRI via divestments is influenced more by cultural and reciprocity norms than their moral commitment to participate in the PRI. In Chapter 3, I study whether investors can reduce their systematic risk exposure by engaging with their portfolio firms to solve environmental issues. Engagements targeting environmental issues that can be solved in the short term reduce firms' systematic risk by 11.3% of a standard deviation two years after the engagement starts. Engagements looking to solve long-term issues (e.g. achieving carbon neutrality) or asking the firm to disclose environmental metrics do not reduce systematic risk in our observed period. Given the systematic nature of environmental risk and the difficulty of hedging it, these findings show how investors can reduce their exposure to environmental risk through activism.
Finally, Chapter 4 studies whether investors use industry classification codes as sustainability metrics. Industry codes are widely available and is used in sustainable finance regulations such as the EU taxonomy; investors make decisions based on mental categories, and ESG scores are often calculated with respect to the firms' industry. Furthermore, a change in a firms' code highlights that a large shift in the firms' activity might have happened. Using a dataset of over 9000 firms from 2010 to 2022, I show that MSCI's Global Industry Classification System (GICS) changes are generally not explained by significant changes in firms' revenue stream or M&A activity. Then, I find that firms for which GICS code changes have lower returns compared to similar firms. Further, using an industry-level sustainability measure based on industry weights in a broad market index and its low carbon equivalent, I find that the negative result on returns is explained by firms' moving to a browner code, while moving to a greener code does not have a negative impact