38541 research outputs found
Sort by
Essays on advertising, growth, and comparative statics
Get PDFThis dissertation presents three studies: the first on the macroeconomics of advertising, the second on growth and the role of competition, and the third on comparative statics.
The first study develops a new general equilibrium model to examine the aggregate effects of advertising. The model captures the two traditional views of advertising—informative and persuasive—and introduces a novel anticompetitive motive. We find that advertising has a significant positive aggregate effect through its role in spreading product awareness.
The second study explores the role of competition in shaping the long-run effect of fiscal policy on growth and the complementarity of fiscal and competition policies. To address these, we develop a step-by-step growth model with endogenous market structure, and we find that the market structure response amplifies the effect of fiscal policy.
The last study, which lies outside the field of macroeconomics, is motivated by the limited tools available to get analytical results in models frequently used in macroeconomics and other fields. It introduces a novel approach to comparative statics, building on Farkas' Lemma, and derives sufficient conditions under different assumptions. An application to an oligopoly model with differentiated goods under CES preferences illustrates the method
Investigating serum biomarkers, disease pathways and vitamin D in association with cardiovascular disease in great apes
Get PDFGreat apes (bonobos, chimpanzees, gorillas and orangutans) in zoological collections play an important role in conservation, and a better understanding of the health challenges they face is crucial. Cardiovascular disease (CVD) is a leading cause of morbidity and mortality, with particular concern arising from a prevalent and poorly understood phenotype: idiopathic myocardial fibrosis (IMF). This thesis investigates diagnostic biomarkers, disease pathways, and vitamin D status as a possible risk factor in CVD, particularly IMF, to address critical knowledge gaps and inform best practice for the management of great apes in human care. The literature review establishes the context for this work by exploring the prevalence and potential aetiopathogeneses of CVD in great apes, highlighting the pressing need for research into IMF. Chapter 1 identifies three potential serum biomarkers of IMF, with one marker in particular showing promise as a novel diagnostic tool, although further validation is required. Chapter 2 assesses the cardiac tissue proteome associated with IMF, showing significant alterations in proteins associated with calcium regulation, mitochondrial and contractile function, and extracellular matrix (ECM) remodelling, revealing key biological pathways involved in IMF progression for the first time. In chapter 3, myocardial gene expression is explored, targeting markers that have been implicated in fibrosis elsewhere. Key pre-analytical and methodological challenges are highlighted, which should be considered in any future work investigating the molecular drivers of IMF. Chapter 4 shifts focus to vitamin D, a potential modifiable risk factor for IMF, revealing widespread low vitamin D status in a large number of great apes in European zoos. UVB exposure, diet, and outdoor access are significant factors influencing vitamin D status in these animals, emphasising the importance of husbandry practices in mitigating potential health risks, though further species-specific investigation is needed. Together, the findings of this thesis advance our understanding of IMF in great apes considerably, and may contribute to the development of evidence-based strategies to improve their health and welfare. Future research should focus on validating novel diagnostic biomarkers and investigating disease pathways in a larger cohort, as well as exploring likely risk factors in conjunction with CVD outcomes more directly, in order to inform interventions to improve health outcomes for these endangered species in human care
Volatile profiling and microbiome analysis of papaya fruit rot caused by Colletotrichum gloeosporioides, Lasiodiplodia theobromae, and Fusarium solani and postharvest control strategies
No full textPapaya (Carica papaya) is a vital crop, particularly in tropical countries like Malaysia, due to its rich nutritional content, economic value, excellent flavour, and applications in drug development and industrial processing. The export of fresh papaya and processed papaya products has become a significant source of income for papaya-growing countries, especially in regions where the demand for tropical fruit is high. However, despite these benefits, papaya's climacteric nature makes it highly susceptible to rapid deterioration, primarily due to severe infections by various pathogens that develop both epiphytically and endophytically during postharvest handling. These irreversible decays lead to substantial changes in overall fruit quality and contribute to significant postharvest losses in papaya-producing countries, including Malaysia. To mitigate these losses, understanding the causal agents of these infections is crucial. Early diagnosis and identification methods have been introduced and implemented to detect the spread of diseases, enabling timely interventions. Additionally, various control strategies are applied to inhibit and delay disease establishment through different modes of action. This thesis aims to elucidate the volatile profile of ‘Sekaki’ papaya during ripening and its changes when infected with Lasiodiplodia theobromae, Fusarium solani, and Colletotrichum gloeosporioides. Furthermore, the microbiome of the whole papaya fruit is analysed using next-generation sequencing (NGS) to understand the impact of fruit ripening and rotting on microbial shifts within the fruit. In addition, the potential of an underutilized crop, Garcinia atroviridis, is explored for its ability to inhibit the growth of L. theobromae, F. solani, and C. gloeosporioides at different concentrations. An in-vivo analysis of G. atroviridis fruit extract against C. gloeosporioides is also conducted, along with an assessment of its impact on the physico-chemical qualities of papaya when applied at varying concentrations.
Solid-phase microextraction coupled with gas chromatography- mass spectrometry (SPME-GC-MS) analysis was conducted on ripe and unripe papaya fruit revealing significant differences in their volatile profiles at different ripening stages. Principal component analysis (PCA) accounted for 20.0% and 31.0% of the variance in the first two components, respectively. The identified volatiles, including alkanes, alcohols, and esters, could serve as potential biomarkers for fruit ripening. Specifically, 4-methyl-1-hexanol and 2,4-dimethylheptane were detected exclusively in unripe fruit, while oxalic acid, butyl propyl ester and pentyl propionate were found in ripe fruit.
Further GC-MS analysis was conducted on papaya fruits infected with C. gloeosporioides, L. theobromae, and F. solani to identify potential biomarkers associated with each pathogen. Based on disease incidence, severity, and PCA, days 1, 3, and 5 were determined to be optimal for volatile profiling. Significant differences in the volatile profiles were observed across these time points. A total of 61, 70, and 68 volatile compounds were detected in samples infected with C. gloeosporioides, L. theobromae, and F. solani, respectively. Methylglyoxal and 1-butanol emerged as potential biomarkers for C. gloeosporioides infection, while 1-pentanol, 1-heptanol, and L-lactic acid were identified for L. theobromae infection, and 1-octanol and β-Phellandrene for F. solani infection.
Additionally, Next- generation sequencing (NGS) was employed for metagenome analysis to detect microbial communities in papaya fruits at different ripening stages and elucidate potential interaction with the host. Alpha diversity analysis revealed a significantly higher bacterial diversity in unripe samples, while the fungal microbiome showed no significant difference between the stages. Beta diversity analysis indicated a significant difference in microbial abundance between unripe and ripe samples, which was further supported by relative abundance data. Specifically, bacterial families Acetobacteraceae and Pseudomonadaceae were more abundant in unripe samples, while Erwiniaceae and Caulobacteraceae were predominant in ripe samples. For the fungal microbiome, Cladosporiaceae, Pichiaceae, and Saccharomycetaceae were significantly more abundant in unripe samples, while pathogenic families Botryosphaeriaceae, Glomerellaceae, and Nectriaceae were more prevalent in ripe samples. Overall, unripe and ripe papaya samples exhibited distinct bacterial and fungal microbiomes in terms of composition, diversity, and abundance.
Metagenome analysis using next-generation sequencing was conducted to investigate microbial shifts during papaya fruit rotting and to understand the roles of each microbe involved. The results revealed that diseased fruits exhibited higher diversity in both bacterial and fungal microbiota compared to healthy samples. Taxonomic characterization identified several pathogenic bacteria and fungi in healthy samples, including Erwinia sp., Enterobacter cloacae, Fusarium solani, Colletotrichum okinawense, and Lasiodiplodia sp. In contrast, the microbiota of diseased samples included various antagonistic microbes with different modes of action against pathogens, such as Pichia kluyveri, Issatchenkia orientalis, Rhodotorula mucilaginosa, and Enterobacter hormaechei. These findings provide valuable insights into the microbial dynamics during fruit rot and highlight the potential of developing antagonistic microbes as biocontrol agents to combat postharvest diseases.
The in-vitro and in-vivo effects of Garcinia atroviridis fruit extract on postharvest diseases were also investigated over an 8-day storage period. The results demonstrated that a concentration of 15 mg/mL of G. atroviridis fruit extract exhibited the highest inhibition capacity against the mycelial growth of Colletotrichum gloeosporioides, Lasiodiplodia theobromae, and Fusarium solani in-vitro. Similarly, the same concentration was able to completely inhibit the development of anthracnose on fruit caused by C. gloeosporioides until day 6, based on assessments of disease incidence and severity.
When evaluating postharvest quality across different treatments, no significant differences were observed in any of the parameters measured, although changes were noted as the fruit ripened from day 0 to day 8. A similar trend was observed in antioxidant analysis, confirming that the fruit extract did not interfere with the normal ripening process while effectively inhibiting the growth and development of phytopathogens. These findings suggest that G. atroviridis fruit extract has the potential to serve as an alternative postharvest strategy for managing postharvest diseases, offering a solution to the limitations of existing technologies
The role of psychological capital in female leadership development in the Malaysian public sector
No full textThis study explores the pivotal role of Psychological Capital (PsyCap) in empowering female leaders within the Malaysian public sector through a basic qualitative research methodology. PsyCap, encompassing self-efficacy, optimism, hope, and resilience, is increasingly recognised as a critical factor in enhancing leadership capabilities and fostering organisational effectiveness. Despite ongoing efforts towards gender parity, female leaders often encounter unique obstacles that can impede their professional advancement and leadership efficacy. This research seeks to deepen the understanding of how PsyCap can help mitigate these challenges and promote leadership excellence among women. This study addresses the gap by providing the dimensions of PsyCap and the motivation for female leadership development in the public sector. It has explored the key dimensions of PsyCap, factors of female leaders' motivation, and female leadership resiliency in the context of the Malaysian public sector. The study is grounded in psychological capital, social role theory, and transfor-sactional leadership theory. It involves in-depth semi-structured interviews and a focus group discussion with 23 female leaders at mid- and premier-level positions across various public sector organisations, capturing rich insights into their experiences and the strategies they employ to harness their PsyCap professionally. A thematic analysis using NVivo was applied to identify the study's themes. The first finding indicates that high levels of PsyCap elements in hope, efficacy, resilience and optimism (H.E.R.O) are instrumental in enhancing the effectiveness of female leaders' leadership in the public sector. Resilience is the most outstanding pattern. Resilience is demonstrated in proactive decision-making and problem-solving, standing firm against negativity, balancing work and personal life, and learning and growing through adversity. Hope is secondly mentioned, emphasises the vision for subordinates' growth and welfare and is driven by accountability. The second finding indicates that participants are motivated to sustain themselves in the public sector due to agility behaviour and career establishment to serve the public. Agility underscores vital internal qualities crucial for effective leadership: integrity, accountability, professionalism, self-confidence, resilience, and a commitment to continuous learning. Establishing a successful career requires practical strategies and tools, including self-awareness assessments and skill-building opportunities. Female leaders’ leadership resiliency is shown as the third finding, based on their ability to have emotional adaptability, be performance-oriented, and lead with integrity. These are key competencies necessary for effective leadership, particularly for female leaders within the public sector. The female leadership framework emphasises that female multidisciplinary psychological capital attributes, female leadership motivation and female leadership resiliency can work synergistically to empower women leaders in the Malaysian public sector. This research highlights the importance of developing and empowering PsyCap among female leadership skills. Thus, public sector organisations can foster these psychological resources to support female leaders' personal and professional growth. Ultimately, this research contributes authoritative insights to the discourse on psychological capital, gender equality and leadership development, offering a robust framework for advancing female leadership in the Malaysian public sector
Design and development of optical biosensors coupling gold nanoparticles or silver nanoclusters with hybridisation chain reaction
No full textOptical biosensors play a crucial role in detecting specific analytes, including nucleic acids, proteins, metabolites and metal ions. Label-free optical biosensors utilising noble metal nanoparticles have the potential to revolutionise detection of cancer due to their high selectivity, sensitivity, and rapid results.
Among the ribonucleic acids (RNA) that have emerged as putative cancer biomarkers, microRNAs (miRs) stand out. However, their low abundance in biological samples necessitates amplification techniques for accurate detection.
In this thesis, the overarching goal is to develop label-free optical biosensors utilising hybridisation chain reaction (HCR) coupled with gold nanoparticles (AuNPs) or silver nanoclusters (AgNCs) as a signal transducer for facile miR detection. HCR is an enzyme-free nucleic acid amplification technique that can be performed under isothermal conditions. A pair of deoxyribonucleic acid (DNA) probes in hairpin conformation were designed as “amplifiers” to simultaneously detect and amplify miR-665, culminating in the formation of nicked double stranded DNA. These DNA hairpins consist of a double-stranded region (stem) and a single-stranded loop and tail (termed ‘toehold) region.
AuNPs are known to aggregate in the presence of salt, resulting in a visible colour change from red to blue. DNA hairpin probes can adsorb to AuNPs, thereby stabilising them against salt-induced aggregation (SIA). In the first project, the effects of the length and sequence of DNA hairpin stem and toehold on their ability to stabilise AuNPs against SIA was investigated. The results showed that hairpins with longer stems generally provided better stabilisation of AuNPs. For hairpins with a 14-base pair (bp) stem and 8-nucleotide (nt) homopolymeric toehold, a stabilisation trend of adenine (A) > cytosine (C) > guanine (G) > thymine (T) was observed. No improvement was observed for 14- and 18-bp hairpins with toeholds having more than eight adenines (-8A). Hairpins with toeholds comprising at least 50% A (with C or G making up the rest) could also result in strong stabilisation. Finally, hairpins with G-rich toeholds (≥ 6G) could form G-quadruplexes and should be avoided due to their reduced AuNPs stabilisation ability. These results served as guidelines to design DNA hairpins which will give strong AuNPs stabilisation and ideally improve the signal-to-background ratio of colorimetric HCR-AuNPs biosensors.
Subsequently, a HCR-AuNPs biosensor to detect miR-665 was developed by applying the aforementioned guidelines in conjunction with HCR hairpin design guidelines. When stabilised by DNA hairpins, the AuNPs were able to withstand aggregation. In contrast, upon HCR triggered by miR-65, the DNA hairpins were utilised and double-stranded HCR products were formed which did not stabilise AuNPs. HCR feasibility was first tested computationally with NUPACK software, and then verified experimentally using gel electrophoresis. The HCR-AuNPs biosensor successfully detected miR-665 with a detection limit of 10.7 nM and a detection range of 5–100 nM, yielding colorimetric results visible to the naked eye within two hours, without the need for enzymes and complicated steps. In addition, this biosensor was highly selective for miR-665 compared to other miRs implicated in ovarian cancer.
The final project explores the feasibility of developing a biosensor that can be more easily customised to detect different miR targets, without the need to constantly redesign HCR hairpins. By utilising a capture probe and ‘universal’ HCR hairpin probes, one of which acts as template for fluorescent AgNCs formation, a proof-of-concept HCR-AgNCs biosensor for miR-665 detection was developed. It had a detection limit of 41 nM and wide detection range of 50–400 nM, yielding ratiometric fluorescence signals within 5.5 hours. This biosensor was highly selective for miR-665 compared to other miRs implicated in ovarian cancer and was capable of single base discrimination. The modular design of the capture probe and DNA hairpins, as well as tuneability of AgNCs fluorescence emission, positions this biosensor for more facile customisation in future miR detection applications
School leadership development in Saudi Arabia: policy-makers’ and participants’ perspectives
Get PDFThis thesis examines school leadership development in Najran, Saudi Arabia by conducting 35 interviews with principals, junior teachers, senior teachers and policy-makers. The study reveals mixed perceptions regarding the effectiveness of leadership development programmes conducted by the Ministry of Education. Policymakers claim that the Ministry is actively working on initiatives to enhance leadership capabilities through developing soft skills and fostering collaboration. Exchange programmes are utilised to facilitate collaboration and networking among teachers, although many of these events are perceived to lack a validated methodology for promoting leadership skills. The Tatweer programme offers some leadership development opportunities, but participation varies significantly across schools. Some schools developed their own successful leadership initiatives, while others lack sufficient support. Self-development emerged as a crucial factor for leadership development, particularly in schools with fewer formal opportunities. Overall, the study suggests that, while Ministry-led programmes are valuable, they need substantial improvement to address the leadership development needs of both junior and senior teachers
Enhancing ESG efforts through reporting: how do we minimize greenwashing? (focused on the SGX energy & utilities sector)
No full textThe integration of Environmental, Social, and Governance (ESG) criteria into corporate strategy has become increasingly crucial as stakeholders demand more sustainable and ethical business practices. However, the concurrent rise of greenwashing—where companies may overstate or inaccurately represent their ESG efforts to appear more environmentally friendly and socially responsible than they actually are—presents a notable challenge. Greenwashing not only undermines stakeholder trust but also jeopardizes the overall credibility of genuine sustainability efforts. This thesis aims to explore how enhanced reporting mechanisms can mitigate the incidence of greenwashing, thereby promoting authentic sustainability practices.
A key component of this research involves understanding the public’s perception of corporate sustainability reporting. Public scrutiny has intensified as consumers, investors, and other stakeholders become more informed and vocal about corporate sustainability practices. This study seeks to incorporate the views of the public by examining how their trust in a company's reported ESG efforts influences their support and investment decisions. Through surveys and interviews, we will gather insights into how transparent and reliable the public perceives current ESG reporting to be, and what improvements they believe are necessary to reduce greenwashing.
Through a comprehensive examination of current ESG reporting standards, regulatory frameworks, and best practices, this study seeks to explore how transparency and accountability can be enhanced through the adoption of unified reporting standards, mandatory disclosures, and the use of advanced technologies for traceability. By examining the roles of regulatory bodies and third-party verifications, this research will highlight effective strategies for minimizing greenwashing. The ultimate goal is to provide actionable recommendations that businesses and policymakers can implement to enhance the integrity of ESG reporting, ensuring that sustainability efforts are genuine and impactful, and fostering greater trust and engagement from the public
The critical driving and success factors for the successful implementation of AI for businesses in the retail industry
No full textArtificial Intelligence (AI) is revolutionizing businesses worldwide and the retail industry is one of the major adopters. However, retailers are struggling to implement AI into their businesses with sustainable success. There are several complex elements tied to implementing and integrating AI within an organisation's ecosystem. This explorative research aims to uncover the critical success factors for successful AI implementation within retail businesses. Qualitative research was conducted through semi-structured interviews with AI experts who had prior retail-related and implementation experience. The research finds 67 critical success factors and categorises them into relevant groups including strategic, organisational, technical, human, ethical and external. The identified factors were scored by the interview participants in terms of significance through a 5-point Likert scale system. The results highlight the “alignment of AI with business goals” and “understanding a customer's problems and delivering business impact” as the most significant success factors for AI implementation in retail. These are followed by the importance of obtaining senior executive buy-in, adequately preparing data for high quality, using cost-effective approaches, continuously monitoring and retraining models and ensuring the ethical use of AI. Aside from a comprehensive list of factors, this study provides a guiding framework to help retail decision-makers prioritise key elements for AI in their implementation journey. For academia, it adds to the existing literature on critical success factors for AI implementation while also providing retail-industry-specific insights
A holistic retrofitting approach to UK residential buildings - a combined PV/PCM/Wall insulation/window system
No full textThis study addresses the urgent need to improve energy efficiency in the construction sector, which accounts for 40% of global energy consumption. In the UK, aging residential buildings pose challenges to reducing carbon emissions, making targeted retrofit strategies essential. Current methods lack an integrated approach, so this research evaluates the combined impact of photovoltaic (PV) systems, phase change materials (PCM), insulation, and advanced glazing on energy efficiency using EnergyPlus simulations.
Findings show that wall insulation is the most cost-effective measure, significantly reducing energy consumption with a short payback period. Combining insulation with PCM further enhances savings but extends the payback time. Low-E vacuum glazing improves efficiency, particularly in colder regions, though with a longer return period. PV systems are financially viable across all regions, cutting energy costs with a 5-6 year payback. Air source heat pumps (ASHP) reduce gas dependency but are impacted by high electricity prices.
The best-performing retrofit combination reduces energy consumption by up to 77%, with colder regions benefiting the most. This study highlights the importance of integrating passive and active technologies tailored to building types and climate conditions to achieve the UK’s 2050 net-zero targets. Government incentives are key to promoting widespread adoption, making energy-efficient retrofits both economically viable and environmentally impactful
Understanding The Interactions of Biomolecules with Fabrics for Improved Fabric Care
No full textThe textile industry faces sustainability challenges, including premature clothing disposal and microplastic pollution. Fabric care products play a vital role in extending garment lifespan, with biologically derived formulations showing promise. However, the understanding of their mechanisms of action remains limited.
Surface analytical techniques, including atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), Raman spectroscopy, water contact angle measurements (WCA) and secondary ion mass spectrometry (ToF and OrbiSIMS), were employed to investigate surface morphology, fabric chemical changes, and the potential mode of action of these products.
Initial studies with AFM revealed morphological changes, albeit with limitations in nanomechanical property measurements. SEM provided insights into topographical challenges and potential fibre damage. DMA demonstrated reduced inter-fibre friction upon biomolecule exposure. Raman spectroscopy showed no evid nce of new covalent bonding, while SIMS identified ubiquitous biomolecule deposition and fabric dependent permeation. WCA analysis demonstrated an increase in surface free energy and hydrophilicity.
Consumer wash cycle samples analysed with OrbiSIMS highlighted biomolecule presence post-washing, offering insights into formulation efficacy. Structure-activity relationship investigations explored biomolecule variations and their impact on strength of adsorption, permeation and mechanical properties.
Formulation development efforts included evaluating existing and novel biomolecule variants for their fabric care properties. Insights gleaned from these experiments shed light on biomolecule-fabric interactions and offer avenues for further research. Addressing these challenges could lead to the development of more effective and sustainable fabric care solutions, contributing to a greener textile industry
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇