PUCK: A Novel Regulator of Arabidopsis Secondary Growth

Secondary growth is thickening of the plant stem, hypocotyl and root, providing structural support and increased nutrient transport to the growing plant. The main driver of secondary growth is the vascular cambium, a bifacial stem cell population which gives rise to xylem and phloem via organised cell division and differentiation. The TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR (TDIF) peptide ligand diffuses into the cambium and signals to the PHLOEM INTERCALATED WITH XYLEM (PXY) receptor-like kinase to promote cell division, vascular organisation and repress xylem identity. However, several aspects of TDIF and PXY biosynthesis, turnover and signalling are not fully understood, in part because all the factors involved have not yet been identified. CLE41 (CLAVATA3/EMBRYO SURROUNDING REGION 41) is the precursor of TDIF. 35S::CLE41 lines, characterised by ectopic cambium, were used in a mutagenesis screen to identify novel TDIF-PXY signalling components. This screen identified PUCK, which contains WD40 repeat domains functioning in protein-protein interactions, as a suppressor of 35S::CLE41. Here, GUS transcriptional reporter analysis revealed that PUCK is expressed in the phloem and xylem parenchyma. Histochemical staining identified how puck affects the differentiated vascular tissue. pxy puck mutants showed a significantly increased xylem width, but no increase in xylem vessels, suggesting PUCK does not regulate xylem differentiation. pxy puck mutants showed a significantly decreased phloem width compared to wild type, but a significantly wider phloem than pxy single mutants. This suggests that PUCK may repress phloem differentiation within the TDIF-PXY pathway. It is hypothesised that PUCK may be a scaffold protein involved in influencing phloem production. Lignified xylem vessels make up woody tissue, therefore, understanding secondary growth could allow manipulation of wood formation to increase forest productivity. Secondary growth also provides stability to plant stems and the phloem allows reallocation of resources, manipulation of which could be useful for increasing climate resilience

Do Algorithms Re-standardise the Life Course? The Role of Social Media for the Third Age in China.

Against the broad backdrop of global population ageing and the digital revolution, this study focuses on algorithmic public social media. It examines how the algorithm and platform reshape the identities of China’s third age and how, in this process, they reproduce and even intensify social inequality. The thesis builds an integrated theoretical framework to address the core research question, the study adopts a multi-level mixed-methods design. At the macro level, the study finds that algorithmic platforms, acting as curators, reshape a standardised ideal third age narrative centred on successful ageing. At the meso level, it shows that users’ digital practices are deeply structured by offline cultural capital. The study proposes the algorithmic cave metaphor to describe the structural information predicament faced by the latter under low algorithmic literacy and high algorithmic dependence. Mechanism analysis not only verifies the conversion pathway of digital capital but also identifies media format thresholds in different format creation. Further micro analysis reveals that the third age cultural landscape on platforms arises from a dual mechanism of capital barriers and platform discipline: high-visibility content is produced strategically and in templated forms by creators with significant capital advantages to compete for scarce attention. In sum, the thesis constructs and validates a cyclical model of the reproduction of inequality, showing how capital, algorithms, and user agency act together to shape age identity construction and social stratification in the digital era. The findings deepen the understanding of the third age, offer new theoretical tools and mechanistic explanations for digital inequality, and carry practical implications for platform governance and digital inclusion policy

Forgotten leaders- English and Irish women religious and the development of secondary education for all Catholic girls in the opening decades of the twentieth century

This thesis examines the role of English and Irish apostolic female religious congregations in establishing secondary schooling for girls in England from the end of the nineteenth century up to the end of the 1920’s. Sisters in apostolic congregations took simple vows, and were not bound to the cloister, but actively engaged in work in the communities in which they lived. They played an important role in parishes and in education, as the Catholic church grew in England in the last quarter of the nineteenth century and early twentieth century. A number of congregations were responsible for establishing girls’ secondary schools, which met standards required by the government in curriculum, teaching, facilities, and examination work, thus enabling them to access government grant funding. This meant that they could offer an affordable education to pupils from families of modest means. The work of these orders in education has been neglected in the literature. Much of the literature describes convents educating girls from well off backgrounds in preparation for marriage and managing the home. In England the literature is based, primarily, on studies of the French orders working in secondary education. The work of English and Irish orders has thus been overlooked. Many of them established provision in poor urban areas, against significant obstacles, and offered opportunities to girls that would not otherwise have been available to them. Evidence from national, convent, school, and diocesan archives demonstrates that the religious sisters invested financially to provide school buildings. They worked as professional teachers in the classroom, and as leaders of their schools to deliver a curriculum that enabled success in examinations. They provided Catholic education for Catholic girls from a wider social background than current research states, using national scholarship systems, so that at least 25% of pupils held free places. In addition, fees were kept low. As a result, girls from different social backgrounds were able to access a good quality of secondary education. The quality of this education, enabled girls to access courses in higher and further education and better employment opportunities. This is underlined by the fact that three times as many girls as boys were able to access a free place in a Catholic grammar school after 1944, because of the foundations laid by female religious orders in recognised schools.

Ageing in motion: An exploration of the ageing situation of the first generation of Chinese migrants and generational interactions

Ageing and migration are two significant global demographic phenomena that are increasingly intertwined and evolving in complex ways. While the intersections of ageing and migration have received broad theoretical attention, the heterogeneity and complexity of ageing migrants’ experiences remain insufficiently addressed. This thesis examines the lived experiences of ageing among Chinese first-generation rural–urban migrants—a group that is largely underrepresented in academic and policy discourse, despite their substantial contributions to family and society. Focusing on older migrants engaged in informal sectors, it asks: What challenges do they encounter, and what plans and expectations shape their lives amid ongoing social transformations? Drawing on ethnographic methods—including participant observation, mobile ethnography, and go-along chats, as well as interviews—this research illustrates the complex inter- and intra-generational dynamics that span urban and rural spaces. It extends the spatial and relational scale of householding analysis and centres older people within these practices. The study critically engages with and extends the existing literature on ageing, migration, and translocal householding, offering a nuanced understanding of intergenerational interactions and support. Drawing on the intersecting analytical perspectives of translocal householding, situated ageing, and compounded precarity, this thesis contributes to existing literature on migration and ageing by addressing the entanglements of vulnerabilities and precarities of older migrants. At the same time, it highlights the vital, yet often overlooked, contributions these migrants make to sustaining households across spatial and generational divides. By foregrounding situated ageing and introducing the lens of compounded precarity, the thesis offers both methodological and conceptual innovation, bridging ageing and migration studies. It reveals how older migrants sustain translocal ties, navigate urban marginality, and reconfigure intergenerational roles amid structural constraints and personal aspirations

Capillary-driven Interactions at Solid and Liquid Interfaces: Adhesion, Bridging, and Removal

Capillarity governs how fluids interact with interfaces, linking fundamental physics with engineering applications. Although the thermodynamics based on surface tension and Laplace pressure are well established, how these interactions evolve across scales and physical environments remains incompletely understood. In this thesis, I investigate three core aspects of interfacial capillarity: particle adhesion, liquid bridging, and capillary-driven droplet removal, aiming to develop a unified framework that connects microscopic interactions to macroscopic function through integrated experiments and quasi-static modelling. Starting from the nanoscale, particle adhesion at liquid interfaces is quantified using atomic force microscopy and modelling. The results show that classical thermodynamics remains valid, with adhesion governed by geometry and wettability, while line tension becomes significant below a characteristic length threshold. This insight supports the design of functional nanoparticles that either resist or promote interfacial adsorption. At millimetre scales, I examine capillary bridges across hydrophilic, hydrophobic, and liquid-infused surfaces. Distinct contact line dynamics are revealed, from pinning and hysteresis on solid surfaces to near-frictionless motion on liquid-infused surfaces, yet all systems can be consistently described by interfacial tension and Laplace pressure. On liquid-infused surfaces, enhanced mobility enables lubricant transfer and amplifies gravity-induced geometric asymmetry, providing design strategies for controlled capillary–substrate interactions. Building on these insights, I introduce a capillary-lifting mechanism for efficient droplet removal. By harnessing high interfacial tension as the driving force for detachment, this approach eliminates the need for surfactants and reduces water consumption. Predictive detachment criteria based on apparent and receding contact angles are validated through agreement between experiments, simulations, and theory. The method is further demonstrated using real-world contaminants and low-additive formulations, highlighting its potential for sustainable cleaning. Together, this thesis establishes a predictive and experimentally validated framework for capillary behaviour from nanometre to millimetre scales, advancing our understanding of how interfacial geometry and chemistry govern capillary forces and liquid morphology. More importantly, this work demonstrates how subtle yet powerful interfacial capillarity can be harnessed to control solid–liquid interactions, direct droplet motion, and achieve efficient liquid removal, opening new opportunities in liquid manipulation, functional materials, and sustainable surface technologies

Stochastic Characterisation of in-situ Soil Strength Properties and their Application to Reliability-based Geotechnical Design

This thesis presents a practical workflow for reliability-based shallow foundation design that uses cone penetration test (CPT) measurements to quantify soil variability and to then inform the random finite element method (RFEM). CPT data from a Norwegian clay site and also from a Saudi Arabian sand site are used, separately, to obtain point and spatial statistics of the relevant in-situ soil measurements, including mean, standard deviation, coefficient of variation, and vertical and horizontal correlation lengths. These statistics are then transformed to the relevant geotechnical parameters. In the case of clays, the in-situ CPT data are converted to undrained shear strength ($s_u$) whereas for sands, cone tip resistances are transformed to the effective friction angle ($\phi'$). This statistical information can be then used as input to a random field generator to compute a field that realistically captures the heterogeneity measured at the site. The random fields in this thesis are generated by the local average subdivision (LAS) method. Standard normal random fields are generated first and these are then transformed into the relevant geotechnical property ($s_u$ or $\phi'$) that matches the target distribution and prescribed statistical moments. These random fields for the relevant geotechnical property are subsequently mapped onto a finite element mesh for random finite element method analyses. \ud The RFEM is used within a Monte Carlo simulation framework to quantify the bearing capacity of a rigid strip footing under short-term undrained conditions (expressed by the bearing capacity factor $N_c$) and under long-term drained conditions (expressed by the bearing capacity factor $N_q$). RFEM stochastic parametric analyses are performed to quantify how variability, correlation length, and anisotropy affect the mean and dispersion of bearing capacity. The computational outcomes from these RFEM parametric analyses are collected in the form of a database that is used to train surrogate models for fast prediction. The prediction capabilities of the trained surrogate models are then tested against independent RFEM benchmarks using in-situ data, including non-stationary cases with depth-dependent mean trends. In particular, the validity of the surrogate models is tested using the statistical information of the Saudi Arabian sand site including pre- and post-vibro-compaction CPT measurements. Overall, the comparisons of the surrogate predictions against the RFEM benchmark solutions show an excellent performance

The relative potential of chemical dissolution driven erosion in limestone bedrock rivers

Identifying how chemical and physical bedrock erosion processes combine is crucial in understanding how upland landscapes evolve through bedrock channel incision. It is well established that abrasion by saltating bedload is a critical process and there is widespread recognition that dissolution of soluble minerals in carbonate bedrock rivers is highly effective, but there has not been work directly quantifying the relative rates of dissolution and abrasion on bedrock incision. Using a combination of laboratory abrasion mill and bedrock cube mass loss experiments, this study assesses the role of dissolution and abrasion across a range of environmental conditions. Laboratory cube experiments were run at three temperature points and three pHs, while field cubes were places at different immersion frequencies in Trout Beck, to see how these factors would affect mass loss. Results showed no difference in mass loss between temperature bands, while pH was a statistically significant indicator of mass loss. The field results showed that immersion time was not the main control on mass loss, with wetting and drying cycles and acidic peat runoff having more control. To compare the contributions of abrasion and dissolution on carbonate rocks, an abrasion mill was used with variable pH solutions, with and without sediment load. In the mill experiments, similar mass loss rates were found for the mill run at pH 7 with bedload (abrasiondriven) and pH 3 with no bedload (dissolution-driven). In addition, the mill experimental runs found evidence that the addition of abrasive tools led to an increase in chemical dissolution rates, while the addition of dissolution did not increase abrasion rates. This study has shown that in low pH carbonate bedrock channels dissolution has the potential to produce similar mass loss as physical processes, challenging the widely accepted paradigm that physical processes are the main control on bedrock channel incision

Chinese Overseas Economic Zones and Chinese Greenfield FDI: An Investigation of Their Impacts on Lowering Liabilities of Foreignness and Promoting Greenfield FDI in Chinese MNEs

Chinese Overseas Economic Zones (COEZs) are used by the Chinese state and Chinese multinational enterprises (MNEs) to facilitate overseas production and entry, yet their geography, investment effects, and buffering role remain insufficiently understood. Using a harmonised COEZ roster over 2003-2018, this thesis links three empirical studies. Study 1 estimates panel logit models of COEZ presence for 167 host economies and shows that market size consistently predicts zone presence, while governance conditions, political instability, and cultural distance shape placement in tier-specific ways. Study 2 applies staggered difference-in-differences with event-study diagnostics and cohort-time estimators in a 165-country panel (2,593 country-years), finding higher Chinese greenfield FDI after COEZ establishment and stronger effects in BRI-active years. Study 3 estimates interaction-based two-way fixed-effects models over a project-year panel spanning 132 hosts and reveals tier asymmetry: national-tier zones attenuate (and sometimes reverse) the institutional-distance penalty, whereas provincial-tier zones in pre-national periods are associated with a steeper distance gradient. Official finance from China is negative in non-COEZ years but less so under COEZ status; zones do not robustly moderate the exports-investment relationship

Auckland Castle: the development of an episcopal palace in County Durham to the 15th century

Taking an interdisciplinary approach, this PhD thesis explores the development of the Bishop of Durham’s palace of Auckland Castle, with a specific focus on the 14th century. During the episcopates of this period, the complex became the pre-eminent episcopal residence in the See of Durham, and the architectural footprint which would dictate its evolution over the subsequent six centuries was established. The form and nature of the structures in the complex were dictated both by the needs of the episcopal office and household, and the personal tastes and relationships of the prelates themselves as the patrons of the actual building works. Though a site of exceptional importance, Auckland Castle has been the subject of a surprisingly limited amount of focused scholarship. Recent archaeological and building refurbishments works have however provided a crucial opportunity to examine the complex and reassess the nature of its historical layout. This thesis utilises the new finding to address this lacuna and provides a detailed and comprehensive assessment of the palace during the medieval period. This study first takes a chronological approach, utilising a range of historical and archaeological evidence and data to establish, as far as possible, the layout of Auckland Castle both in the preceding 12th and 13th centuries, and then during the period of focus in the 14th century. It then explores in depth the historical context for several of the key structures (the great chamber, chapel, and gatehouse) alongside the lives of the bishops who initiated the construction. In this way the study aims to establish the fullest understanding of these high-status structures within the palace site, whilst enabling future wider comparison to occur with other elite residences across the northeast of England and further afield

Regulation of AI-generated disinformation by online platforms: A comparative analysis perspective

The rise of Generative artificial intelligence has transformed the generation and dissemination of disinformation, accelerating its spread and expanding its reach. This thesis will examine how the European Union, the United States, and China are addressing the regulation of AI-generated disinformation and placing primary regulatory liability on online platforms. Using comparative study, case study, and doctrinal study, this thesis will analyze the historical evolution of platform liability regimes and current regulatory measures across jurisdictions. The findings reveal that the EU’s regulatory approach emphasizes transparency and requirements under the Digital Services Act and content moderation obligations imposed on VLOPs, while the US’s regulatory framework prioritizes free speech and provides intermediaries with immunity under Section 230. China, on the other hand, adopts a state-led regulatory approach that encourages online platforms to proactively conduct content moderation. The significance of this research lies in analyzing how inadequacies or ambiguities in various jurisdictions’ laws and regulations lead to enforcement difficulties and how malicious disinformation producers exploit these inadequacies to circumvent regulation. Furthermore, it offers feasible recommendations for establishing a cross-jurisdictional collaborative framework for addressing AI-generated disinformation