SACM - United Kingdom
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9667
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Item Restricted Empirical Investigations On Determinants Of The UK Stock Market(Saudi Digital Library, 2025) Nahi, Shada; Bissoondeeal, RakeshThis thesis examines the determinants of the UK stock market and their interactions under periods of stress. It explores three key factors influencing stock price performance. In particular, these factors are macroeconomic variables, firms’ Environmental, Social, and Governance (ESG) ratings, and Bitcoin bubbles. The research is structured into three main objectives. First, it investigates the causal relationship between macroeconomic indicators and stock prices by employing both standard and quantile Granger causality methods to capture the variation of sectoral and economic conditions. Second, it analyzes the impact of firms’ ESG ratings on stock price crash risk using a fixed effects model to examine whether ESG factors contribute to market stability and focus on prior and post COVID-19 periods. The last objective explores the financial contagion effects of Bitcoin bubbles on stock market volatility by detecting bubble periods using the GSADF test and analysing their impact on sectoral volatility using the GARCH-X model. The findings reveal significant macroeconomic influences on stock prices with sectoral differences in causality patterns. The quantile Granger causality approach provides deeper knowledge of bidirectional relationships under varying economic conditions. ESG ratings exhibit mixed effects on stock price crash risk before and during the COVID-19 crisis and reveal sectoral variations. Bitcoin bubbles reported varying impacts on stock market volatility. Specifically, the relationship had changed from a hedging role in pre-pandemic periods to a volatility factor during crises. These results have important implications for investors, policymakers, and financial analysts. Further, it highlights the necessity for adaptive investment strategies, regulatory considerations, and risk management approaches focusing on sector-specific and economic conditions.8 0Item Embargo The Dissolution and Fabrication of Hybrid Cellulose- Protein composites in Ionic Liquid of 1- ethyl-3-methyl- imidazolium acetate [Emim][OAc](Saudi Digital Library, 2026) Alqarni, Samiah; Hine, Peter; Ries, MichaelThe increasing demand for sustainable and environmentally friendly materials has accelerated research into renewable bio-based composites as alternatives to conventional petroleum-derived systems. This thesis investigates the dissolution behaviour, structural transformation, and fabrication of all-hybrid cellulose composites based on cellulose–protein systems using hemp–keratin and flax–silk hybrid yarns and woven fabrics. The ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) was employed as a solvent to achieve controlled partial dissolution, enabling the formation of regenerated matrix phases while preserving part of the original fibrous reinforcement structure. The dissolution behaviour of hemp–keratin and flax–silk hybrid yarns was systematically studied as a function of temperature and time using optical microscopy (OM), wide-angle X-ray diffraction (XRD), gravimetric analysis, and mechanical testing. The results demonstrated that dissolution strongly depends on both processing temperature and dissolution time, with cellulose dissolving more rapidly than protein components. In hemp–keratin systems, cellulose dissolution occurred at lower temperatures, while keratin required significantly higher energy due to the presence of disulfide bonds. Activation energies determined using time–temperature superposition (TTS) analysis and Arrhenius modelling were 55 ± 5 kJ/mol for hemp cellulose and 111 ± 9 kJ/mol for wool keratin. For flax–silk hybrid yarns, optical microscopy revealed distinct dissolution mechanisms for each component. Cellulose dissolved progressively from the outer surface inward, forming a coagulated matrix layer that gradually restricted further ionic liquid penetration. In contrast, silk dissolved individually from the outer surfaces of each filament, initially filling internal gaps before merging with the cellulose matrix at later stages of dissolution. XRD analysis confirmed the transformation of cellulose I into cellulose II and amorphous cellulose during dissolution and regeneration. The raw flax–silk yarn contained approximately 57 % cellulose I, which decreased to 8 % after treatment at 50 °C for 2 hours, while cellulose II increased to 23 %. Evidence of overlapping diffraction peaks indicated intermolecular interactions and partial phase mixing between cellulose and silk. TTS analysis demonstrated Arrhenius-type behaviour for both components, yielding activation energies of 95 ± 5 kJ/mol for flax cellulose and 76 ± 9 kJ/mol for silk. Mechanical analysis yielded activation energies of 73–82 kJ/mol, consistent with structural observations. Following the yarn-scale studies, all-hybrid woven composites were fabricated from hemp–keratin and flax–silk fabrics using two processing routes: an excess ionic liquid bath process and a batch process. Mechanical testing showed that Young’s modulus and tensile strength initially increased with dissolution temperature due to improved interfacial bonding and matrix formation, before decreasing at higher temperatures because of excessive dissolution of the reinforcing fibrous network. This behaviour confirmed the existence of a preformed stage during composite consolidation. The incorporation of an interlayer cellulose film significantly improved peel strength and interfacial adhesion by promoting the formation of a continuous regenerated matrix at the interface, although increased matrix content reduced stiffness under some conditions. Cellulose–keratin composites consistently exhibited higher stiffness than cellulose–silk composites, while differences between warp and weft directions highlighted the influence of fabric architecture, yarn alignment, and crimp on composite performance. TTS analysis of woven composites further confirmed Arrhenius-type dissolution behaviour at the fabric scale and produced an activation energy of 16 ± 3 kJ/mol, providing quantitative insight into the dissolution kinetics at the fabric scale. The relatively low activation energy compared to individual hybrid yarn systems suggests that the woven architecture and partial dissolution–consolidation mechanism facilitate solvent transport and matrix formation during composite processing. Overall, this thesis demonstrates that [Emim][OAc] is an effective solvent for producing sustainable all-hybrid cellulose composites through controlled partial dissolution of cellulose–protein fibre systems. The work provides new insight into dissolution kinetics, structural evolution, interfacial interactions, and structure–property relationships in hybrid biopolymer composites, contributing to the development of high-performance renewable materials for sustainable engineering applications.6 0Item Restricted Phage-based deodorant : Isolation and characterisation of bacteriophages targeting odour-generating Staphylococcus species and expression of recombinant phage endolysins(Saudi Digital Library, 2026) Alahmadi, Abdullah; Galyov, EdouardAbstract Human axillary malodour arises when secretions from sebaceous, eccrine, and apocrine glands are biotransformed by skin bacteria into volatile fatty acids, thioalcohols, and steroid derivatives. Broad-spectrum preservatives used in deodorants can suppress odour but disrupt skin homeostasis. A selective strategy is to deploy lytic bacteriophages or their phage-encoded, peptidoglycan-degrading enzymes (endolysins) against the principal odour-driving taxa, notably Staphylococcus hominis. A panel of 15 novel phages active against odour-associated staphylococci was assembled, with detailed characterisation focused on a lead lytic isolate, AA001 Staphylococcus phage, recovered on S. hominis. AA001 displayed a narrow plaque host range yet encoded an unusual two-lysin lysis cassette upstream of a holin. The two endolysins named AaeA (CHAP-SH3b, 256 aa) and AaeB (CHAP/NlpC/P60–SH3b, 320 aa); AaeA carries the predicted catalytic triad Cys134/His140/Asn143 - 144, and AaeB Cys140/His154/Asn160. were cloned and expressed as N-terminal GST fusions (pLEICS 14) and in a T7/His system. fusions partitioned to inclusion bodies but retained activity following 2 M urea solubilisation. A Tris/NaCl/Triton shifted expression into the soluble fraction: SDS PAGE of clarified lysates consistently showed a three-band signature fusion (~56/62 kDa), tag-free endolysin (~30/36 kDa), and free GST (~26 kDa). Glutathione chromatography enriched the fusion, whereas tag-free species predominated in flow through/washes; anti-GST Westerns reported GST-bearing bands only. Functionally, both the soluble supernatant and glutathione eluates exhibited lytic activity on staphylococci, and broth killing (OD₆₀₀) confirmed rapid, treatment-dependent inhibition with the potency order AaeA+AaeB cocktail > AaeB ≥ AaeA ≫ phage AA001 > control for S. hominis; the same ordering held for S. aureus with a smaller dynamic range. In the T7 system, recombinant lysates were likewise soluble and active, whereas native Ni-NTA capture of the ~30/36 kDa species was inefficient, consistent with tag processing or masking. Collectively, these results establish soluble, highly active endolysins from a staphylococcal phage, demonstrate broader enzyme activity than the parent phage’s plaque host range, and support their potential as selective, microbiome-sparing actives for deodorant-adjacent applications.8 0Item Restricted The Potential of Animated Videos In The Development of English Tense-Aspect Usage For Saudi EFL Learners(Saudi Digital Library, 2026) Alshahrani, Sarah; Alshahrani, SarahLearning to use the English tense-aspect (TA) system appropriately appears to be one of the greatest challenges that EFL students face (Celce-Murcia et al., 1999, p. 131), with Saudi learners experiencing particular difficulty due to fundamental typological differences between Arabic and English temporal-aspectual systems. While explicit instruction raises metalinguistic awareness, it frequently fails to produce mastery of complex TA structures (Ellis, 2015). This study investigates whether multimedia-based incidental learning through animated videos offers a more effective alternative to traditional text-based instruction, and examines whether visual input enhancement, specifically, colour-coded caption highlighting, increases learning effectiveness. Sixty female intermediate Saudi EFL learners were assigned to three instructional conditions and were taught usage of three TAs: Simple Past, Present Perfect, and Present Perfect Progressive. The Control Group (N=20) received traditional text-only instruction through written dialogues. The Non-Enhanced Treatment Group (N=20) watched identical animated videos with standard black-font captions without visual enhancement. The Enhanced Treatment Group (N=20) viewed 2D character-based animated videos with red-font colour-coded captions highlighting target TA items. The animations presented TA forms through meaningful character dialogue and narrative contexts but did not include explicit visual illustrations of temporal concepts such as timelines or temporal markers. Learners' knowledge was assessed before the intervention and immediately post-intervention through four task types: forced-choice judgments, verb selections, cloze completion tasks, and error correction exercises. Learner attitudes were measured through post-treatment questionnaires assessing enjoyment, anxiety, and perceived usefulness. Generalised Linear Mixed-Effects modelling revealed unexpected patterns contradicting theoretical predictions. The Non-Enhanced Treatment Group demonstrated the strongest and most statistically significant improvement, while the Enhanced Treatment Group showed modest but significant gains, and the Control Group displayed negligible improvement. Paradoxically, attitude data revealed an opposite relationship with learning outcomes. The Control group reported highest enjoyment, lowest anxiety, and strongest perceived usefulness despite minimal learning gains. Conversely, the non-enhanced group, which learned most, reported lowest enjoyment, highest anxiety, and lowest perceived usefulness. The Enhanced group exhibited intermediate attitudes between these extremes. This research advances understanding of multimedia-based grammar instruction for Saudi EFL learners while highlighting the importance of balancing cognitive outcomes with affective dimensions in materials development and instructional implementation.5 0Item Restricted Sustainability and Accountability in Debt Finance: A Comparative Analysis of Green Bonds and Sukuk(Saudi Digital Library, 2026) Merdad, Roya; Schilling De Carvalho, PedroThis dissertation examines how ICMA Green Bonds and Sukuk address similar sustainability and accountability concerns in debt finance through different institutional and governance mechanisms. It compares the governance architecture of both instruments, assesses how these mechanisms operate in practice, and considers what lessons each framework can offer the other to improve governance outcomes. The analysis demonstrates that Sukuk embed sustainability and accountability through asset-backing, Shariah compliance and supervisory oversight, while ICMA Green Bonds rely primarily on use-of-proceeds requirements, disclosure, reporting and market discipline. In practice, ICMA Green Bonds benefit from scalability, market standardisation and significant capital mobilisation, but face challenges including greenwashing, information asymmetry and limited binding enforcement. Sukuk provide stronger pre-issuance oversight and a closer connection between financing and real economic activity, but their effectiveness is weakened by fragmentation across jurisdictions, differing interpretations of Shariah principles and uncertainty regarding consistent post-issuance monitoring. The dissertation therefore concludes that neither framework provides a universally superior model of sustainable debt finance. Instead, each offers distinct strengths that can inform improvements to the other. ICMA Green Bonds could benefit from stronger oversight, asset-backing and legally enforceable disclosure, while Sukuk could benefit from greater standardisation and consistency across jurisdictions. Both frameworks would also benefit from stronger post-issuance monitoring to ensure that governance commitments remain effective throughout the life cycle of the instruments.4 0Item Restricted Advancing understanding of post-stroke dysarthria in the UK and Arabic-speaking populations: Clinical practice, communication outcomes, and lived experiences(Saudi Digital Library, 2026) Benafif, Shahd; Mitchell, Claire; Conroy, PaulDysarthria, a motor speech disorder affecting the neuromuscular system underlying speech production, is a common sequela of stroke and has significant functional and psychosocial consequences. This PhD thesis aimed to advance understanding of post-stroke dysarthria in both UK English-speaking and general Arabic-speaking populations by examining clinical practice, communication outcomes, and the lived experiences of stroke survivors. The thesis comprises four interrelated studies: a systematic review and three empirical studies. The first study was a systematic review that identified 14 measurement instruments across 9 studies for the assessment of non-progressive dysarthria in Arabic-speaking contexts. These instruments were evaluated in terms of their availability, clinical utility, psychometric properties, and alignment with the ICF framework. Most were clinician-rated, focused on impairment, and based on norms derived from English-speaking populations. The second study explored assessment and treatment practices through surveying 55 SLTs working with Arabic-speaking stroke survivors. Building on the findings of the systematic review, the survey examined the extent to which the identified instruments are used in clinical practice. The survey indicated that, although the availability of some of these tools were reported, two-thirds of SLTs relied on informal assessments. Clinicians also highlighted the need for formal, culturally and linguistically appropriate tools. The third study was a quantitative investigation describing the baseline demographic and clinical profile of 169 stroke survivors with dysarthria in the UK, a well-established healthcare and research context. It also examined communication outcomes and the relationship between assessment domains and patient and clinician perspectives, demonstrating alignment across ICF domains and positive associations between clinician-rated and patient-reported outcomes. The fourth study explored the lived experiences of stroke survivors with dysarthria in the UK through qualitative semi-structured interviews with 27 participants. Findings indicate that communication is shaped by interacting factors, including speech difficulties, co-occurring impairments, and the cognitive and emotional demands of social interaction, with significant implications for self-image and participation. Collectively, these studies provide a comprehensive, multidimensional understanding of post-stroke dysarthria. They highlight the need for culturally and linguistically appropriate tools and a holistic understanding of stroke survivors with dysarthria, including co-occurring impairments. They further emphasise the importance of incorporating the patient perspective to support person-centred care within contemporary stroke pathways. The findings establish a clear agenda for future research, particularly to continue exploring the long-term impact of dysarthria, develop comprehensive frameworks for dysarthria management in Arabic-speaking contexts, and explore the lived experiences of Arabic-speaking stroke survivors with dysarthria.20 0Item Restricted A Study of Domestic and Inbound Tourism Trends in Saudi Arabia(Saudi Digital Library, 2026) ALSAAD, MANSOUR FAHAD; Atefeh, KhazaeiDomestic Tourism , Inbound Tourism , Saudi Arabia , Tourism Trends , Data Analytics , Tourism Analysis5 0Item Restricted Decentralised Finance and Cryptocurrency: Exploring Market, Risks, and the Drivers of a Transforming Financial Landscape(Saudi Digital Library, 2026) Alsaab, Anoud; Kim, Suhee; Zhang,, Jason; Choudhry, TaufiqThis thesis examines the interconnections between decentralised finance (DeFi), traditional banking systems, and macroeconomic forces, and evaluates their implications for financial stability and portfolio management. The rapid expansion of DeFi and its increasing interaction with established financial markets raise important questions regarding systemic risk transmission and the sensitivity of decentralised assets to macroeconomic conditions. The study adopts a three-part structure. First, a systematic literature review synthesises existing research on cryptocurrency and DeFi markets, identifying behavioural, institutional, and methodological gaps that motivate the empirical analysis. Second, the thesis investigates the interconnectedness between DeFi tokens and international banking indices using a time-varying parameter vector autoregressive framework. The results indicate substantial and evolving spillover effects between decentralised and traditional markets, with banking indices generally acting as net transmitters of shocks and DeFi assets frequently operating as net receivers, particularly during periods of elevated global uncertainty. Third, the analysis evaluates the impact of key macroeconomic variables, including interest rates, inflation, and market volatility, on DeFi markets in comparison with traditional cryptocurrencies. The findings suggest that DeFi assets exhibit considerable sensitivity to macroeconomic shocks, while certain stable assets display relatively greater resilience. The portfolio analysis suggests that DeFi assets may provide diversification benefits under stable market conditions; however, these benefits weaken during periods of stress, reflecting the evolving integration of decentralised and traditional financial systems. Overall, the thesis demonstrates that DeFi occupies an intermediary position within the financial ecosystem: it is neither fully detached from nor fully integrated with traditional finance. These findings contribute to the understanding of financial interconnectedness in decentralised markets and offer insights for investors and policymakers concerned with innovation, risk management, and financial stability.4 0Item Restricted Science teachers’ perceptions of, and requirements regarding I-STEM in Saudi Arabia(Saudi Digital Library, 2026) Alahmari, Amal Dhafer A; Lindsay, Hetherington; Victoria, WongAbstract Universally, i-STEM is one of the most rapidly expanding sectors of educational reform. Following Saudi Arabia's establishment, the educational system has undergone numerous reform initiatives to enhance the quality of instruction and the learning experience of students. The issue of how to prepare teachers to use innovative approaches in science education is one of the key challenges confronting the educational system in Saudi Arabia. Regrettably, it has been implemented in the Kingdom of Saudi Arabia without a comprehensive explanation of its objectives, objectives, and framework of application. I-STEM is widely acknowledged as a method of enhancing science curricula; however, its precise implications remain uncertain, as any intervention or modification in any of the subjects related to science, mathematics, engineering, or technology can be considered a i-STEM implementation. The objective of this research study is to examine the instructional practices and perceptions of teachers regarding the science curricula in order to advance i-STEM reform in the Kingdom of Saudi Arabia. To contribute to the enhancement of Saudi Arabia's educational system and the calibre of its students, particularly in the field of science. This can be resolved by addressing the current lacuna in the Saudi literature that has neglected to acknowledge the significance of teachers' perspectives and perceptions regarding educational matters. The study also furnishes the MOE with new information regarding significant issues that will be addressed in future educational reforms and policies. The intent of this investigation is to investigate the perspectives of science educators on i-STEM. It also endeavours to ascertain the perspectives of educators regarding the contextual factors that either facilitate or impede the implementation of this pedagogy in their educational institutions. A mixed-method design was selected as an appropriate approach to investigate the perceptions and applied instructional practices of teachers in Saudi Arabia as a preliminary step towards the implementation of i-STEM. The quantitative component of the study consisted of a questionnaire that was distributed to 126 female middle school science teachers, and the qualitative phase consisted of interviews with 15 female science teachers. The study revealed a significant degree of variation in the manner in which teachers interpreted and implemented i-STEM in their institutions. Additionally, educators implemented i-STEM activities without intending to do so. Participants believed that i-STEM was more engaging for their students than conventional subjects; however, they were limited in their planning by the diverse school regimes that governed assessment, curricula, and timetables. These structural and systemic impediments are a fundamental challenge for i-STEM. The study concludes with suggestions for the legislative reform of i-STEM education in Saudi Arabia, which will involve the reorganisation and further correlation of topics within individual STEM subjects to ensure that they align with other related subjects in the curriculum. Furthermore, there is a necessity for the coordination of teachers who teach various i-STEM disciplines, as well as the re-design and restructuring of teachers' development programs and seminars in conjunction with i-STEM training and implementation practices. In the absence of a formal i-STEM curriculum and available professional development opportunities, the significance of developing support structures that embrace a coherent and cohesive view of i-STEM is underscored by the insights from this study. These structures should be designed to accommodate variations in context, as well as teacher interest and experience.4 0Item Restricted Population Ageing and Economic Growth in the G7, 1995–2020(Saudi Digital Library, 2025) Almutairi, Kholoud; Nasir, Muhammad AliPopulation ageing is one of the defining demographic and economic challenges of the 21st century, particularly in advanced economies. This dissertation examines the population ageing and economic growth in the G7 countries (Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States) over the period 1995 – 2020. Ageing is measured along three dimensions: the share of the population aged 65 and above, the old age dependency ratio, and labour force participation among older workers. A balanced panel dataset is used, and the empirical strategy uses fixed effects and random effects estimators, with model choice guided by specification tests. Robustness checks incorporate health expenditure, 2008 financial crisis effects, and Driscoll–Kraay standard errors, while sensitivity tests introduce lagged regressors and the exclusion of Japan as a benchmark case. The results show that ageing does not cause a same negative effect on growth. In baseline specifications, both the elderly share, and dependency ratio tend to reduce growth, consistent with theoretical expectations. However, once savings, health expenditure, and global shocks are controlled for, these effects weaken or turn positive, highlighting the conditional nature of the population ageing growth relationship. Labour force participation among older individuals does not consistently contribute to growth, suggesting that extended working ages solely are insufficient to offset demographic pressures. The implications are threefold. First, savings and capital accumulation play a central role in boosting the economic effects of ageing. Second, global shocks, particularly the 2008 financial crisis, strongly mediate the link between demographics and growth. Third, policy measures focused solely on extending working ages are unlikely to deliver growth benefits without parallel efforts to enhance productivity and create age friendly labour markets. Overall, the dissertation concludes that population ageing in the G7 is not an inevitable drag on growth, but a complex process shaped by savings behaviour, labour market dynamics, and exposure to shocks. With appropriate institutional and policy responses, advanced economies can adapt to demographic change while sustaining economic performance.10 0