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Spatiotemporal dynamics of invasive crayfish ecology
Get PDFIn order to build a new understanding of the spatial temporal invasion and impact dynamics of a
data-deficient invasive crayfish Pontastacus leptodactylus, this thesis combines systematic
review techniques, fieldwork, and experimental methods. Throughout the thesis, the role of
individual behavioural and morphological variation is integrated into the approaches, to allow
new insights into how these factors shape establishment, range expansion, and ecological
impact. In Chapter 2, literature was reviewed and synthesised which revealed a consistent
directional trend in morphological traits with behaviour being more variable along the invasion
gradient. Chapter 3 demonstrates, through the use of biomonitoring, that early-stage invasions
have little effect on macroinvertebrate community suggesting little impact at low crayfish
densities. Chapter 4 shows morphological traits do vary along the invasion gradient, and whilst
this couldn’t be linked to behavioural traits, behavioural variation between individuals did exist.
Together, these approaches showed that invasion dispersal and establishment can be determined
by morphology and behaviour which can be used for targeted management as invasive species
begin to spread
Writing Women in the Female-Only Biographical Dictionaries: Authorship and Authority in a Reinvented Genre
No full textThe study of history may be approached from a variety of perspectives: as a chronology of events, an analysis of physical artefacts, or the study of individuals or groups. It is with the lattermost of these that the Islamicate historiographical tradition is concerned in its conception of the biographical dictionary: a collection of self-contained biographies that encapsulate the lives of a selection of individuals. Hundreds of such dictionaries have been produced since the earliest eras of Islamicate history, presenting the lives of individuals from various groups and strata in society, from the scholars and elites of different time periods, disciplines, and regions, to collections on strange and eccentric individuals.
This approach to history has been adopted by numerous modern authors writing in a range of languages who seek to recover a history of women in the Islamicate world through the creation of dictionaries on exemplary female figures. Since the start of the nineteenth century, there have been more than 500 such dictionaries compiled – ultimately challenging the thesis of a socio-intellectual decline in the Islamicate world. My research studies these female-only dictionaries by tracing the trajectory of their precursor in the Islamicate biographical tradition before merging them under the newly conceptualised genre of Female-Only Biographical Dictionaries (FOBDs). These works present fascinating insights into the novel ways that the classical genre of the biographical dictionary is reshaped according to the exigencies and perspectives of a new age, (re)introducing to us incredible women from a diversity of times, places and social status. These FOBDs are divergent in the aims and methods of their authors, as well as the background contexts in which they operate, yet all may be united under a shared vision of an Islamicate Women’s Republic of Excellence, connecting a contemporary Islamicate world that is grappling with a complex gender discourse to a magnificently rich past of exemplary women. The present study identifies and examines this genre for the first time, through a representative selection of key works and exemplary and inspiring women
Structural evolution, deformation processes and magmatism in Kadabora-El Sibai district, Egyptian Eastern Desert: Implications for Pan-African Tectonics of the Arabian-Nubian Shield
No full textThe Arabian-Nubian Shield (ANS) represents one of the best-preserved and well-exposed of tracts Neoproterozoic juvenile continental crust offering a unique opportunity for improving our understanding of tectonic and magmatic processes of the Earth’s crust. Detailed microstructural analyses utilizing modern analytical techniques such as Electron Backscatter Diffraction analysis to understand the processes associated with major deformation and tectonic events in the ANS are currently absent. Such studies are crucial to understand its evolution in particular as well as the deformation and rheological behaviour of the Earth’s crust in general. Furthermore, the link between tectonics and magmatism in ANS is still ambiguous. Kadabora-El Sibai region in the Egyptian Eastern Desert (EED), ANS is considered a key region within the shield as it displays most of the essential features recorded elsewhere in the EED, in terms of polyphase deformation and tectonic evolution. Several magmatic rocks including granitoids and dykes are abundant in the area, however, they are poorly-studied but can substantially contribute to the comprehension of the tectonomagmatic evolution of the shield. In addition, several granitic shear zones and associated deformed mafic rocks, that can help advance our understanding of the deformation of the crust, are reported from the area. This thesis employs a multidisciplinary approach integrating field, microstructural and geochemical investigations with isotopic and geochronological data to addresses two topics: the deformation and rheology of the middle crust along with the tectonomagmatic evolution of the ANS
Artificial intelligence for the detection of recurrence in cancer patients
No full textThe recurrence and progression of cancer represent critical junctures in a patient’s
care and valuable opportunities to improve future treatment. Unfortunately, these
clinical endpoints are poorly recorded in healthcare datasets, requiring manual abstraction from unstructured clinical notes. Prior research into automating their
detection has focused on common cancers, first-recurrence events, simplistic methods, and has lacked access to curated datasets for external validation. This thesis
addresses these gaps through a series of case studies using Electronic Health Record
(EHR) data from patients with Epithelial Ovarian Cancer (EOC). It demonstrates
that while rule-based methods that search for disease-free intervals can identify a
limited subset of worsening cancer events, they are insufficient to detect successive events beyond the first recurrence. By contrast, simple data-driven Machine
Learning (ML) approaches, including Classification and Regression Tree (CART),
Random Forests, and gradient-boosted trees, effectively capture the relationship
between routinely collected data and successive, clinically relevant recurrence and
progression events. These events were found to be detectable from local features,
with the inclusion of features encoded by recurrent neural networks, which capture long-term dependencies, providing no significant improvement over simple ML
approaches using localised information. Finally, externally validating UK-trained
models on a US institution highlighted the central challenge in this domain: the
need for a consensus on what defines a clinically meaningful endpoint. Although
future work may refine model performance by rewarding detections that occur close
to the true event or by using earlier detections to support the identification of later
events, these technical advances cannot resolve the core limitation: the absence of
a globally recognised definition of what characterises a clinically relevant worsening
of a patient’s cancer. This lack of consensus not only hinders the development and
deployment of automated detection models but also undermines current research
aimed at improving the treatment of cancer patients
Development of new reduced activation ferritic/martensitic steels with higher temperature capability and improved properties
Get PDFReduced Activation Ferritic/Martensitic (RAFM) steels are considered as candidate materials for the first wall of future fusion reactors. Previous development of RAFM steels has primarily focused on 8-9 wt.% Cr compositions containing abundant M23C6 precipitates (M = Cr-rich) and minor MX precipitates (M = Ta/V, X = C/N), which exhibit significant degradation in strength and fracture toughness at elevated temperatures (550~650°C). Thermomechanical treatment (TMT) can be employed to refine grain size and promote MX precipitation to enhance the high temperature mechanical properties of RAFM steels. In this work, the microstructure, precipitation behaviour, TMT processes, and mechanical properties of four RAFM steels were investigated: the conventional Eurofer 97 from EU and CNA2 from Oak Ridge National Laboratory as baseline RAFM steels, along with two newly designed RAFM steels based on these baseline: Ti-RAFM (with 0.1 wt.% Ti addition) and N-RAFM (with 0.077 wt.% N addition). Through multi-stage hot deformation and multiple passes of final deformation followed by optimized heat treatment processes, the two new RAFM steels achieved significant grain refinement and substantial MX precipitation. The dominant mechanism for grain refinement was primarily associated with recrystallization mechanism, while the increased MX precipitation was related to strain induced precipitation (SIP) mechanism and optimized alloy design. Furthermore, both new RAFM steels demonstrated comprehensive improvements compared to Eurofer 97, with a 17% increase in ultimate tensile strength (UTS) and a 75% enhancement in ductility. Simultaneously, both new RAFM steels addressed the drawback of CNAs where strength improvement came at the expense of reduced ductility
Synthesis of Thiazoline Based Inhibitors for O-GlcNAcase
Get PDFO-GlcNAcylation is a dynamic post-translational modification that regulates numerous cellular processes and is implicated in several diseases.1-13 This modification is reversed by O- GlcNAcase (OGA) a glycoside hydrolase from the family GH84. Due to the involvement of OGA in disease and the limited understanding of O-GlcNAcylation further understanding of the roles OGA plays are required. To facilitate greater understanding of OGA activity-based probes could play an important role as they selectively label active populations of the target enzyme. For the development of ABPs to start a covalent inhibitor must be found. Covalent binding between the inhibitor and the enzyme is a prerequisite for permanent labelling. Several OGA inhibitors exist, but none are capable of forming a covalent bond to the target enzyme. This thesis addresses the development of novel thiazoline-based OGA inhibitors that contain electrophilic warheads targeted against the catalytic base in OGA and a pocket bound cysteine residue. The research builds upon existing scaffolds such as Thiamet-G, aiming to explore structural analogues that exploit the catalytic mechanism of OGA and its active site configuration. Here, the synthesis and where relevant the biological evaluation of three distinct series of thiazoline-based inhibitors are shown. In Chapter I, efforts to synthesise covalent inhibitors based on epoxide-bearing glucose analogues were met with challenges in regioselectivity and synthetic accessibility. Chapter II details the design and synthesis of thiazoline derivatives bearing electrophilic warheads. These compounds demonstrated micromolar potency in vitro. In Chapter III, further analogues were synthesised containing chloro-, iodo- and bromo- acetic derived analogues of Thiamet-G which showed low nanomolar potency against OGA in vitro.
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300
The distribution and value of early warning signals in food webs under stress
Get PDFStress caused by human activity has many impacts on ecosystems, which may result in extinctions and tipping points to detrimental alternate stable states. Early warning signals (EWS) are a tool developed in simple theoretical systems, to predict when extinctions or tipping points are approaching. Current understanding of EWS in complex systems, which better represent natural ecosystems, is limited. Through a series of simulation experiments, this thesis provides insight into the expected strength and distribution of EWS in complex food webs, providing greater applicability for EWS empirically. Chapter 2 assesses the ability of EWS, biomass-based metrics and species’ topological properties to predict where and when extinctions will occur in a food web under stress. EWS were found to be the best predictors, indicating distinctively low resilience in species approaching extinction. This provides value for EWS in complex food webs. Chapter 3 uses a network’s topological properties to predict EWS distribution, finding that specialists of low trophic levels have the greatest capacity for EWS. This makes such species ideal candidates for monitoring, particularly under widespread stress. This is important where monitoring the entire network is impractical. Chapter 4 explores how the location of localised stress impacts EWS distribution, and how EWS propagate from species directly under stress. Here, changes in biomass flux were found to have a crucial role. Change in biomass flux is mediated by a species’ trophic relationship with directly stressed species. This provides crucial context for how a species may be being impacted by stress, based upon the observed EWS. In Chapter 5 I discuss how the key findings of my work, such EWS capacity and the role of biomass flux, can be utilised to improve our understanding of EWS in complex systems. Valuable future research directions include understanding EWS cascades and the impact of more complex stress regimes
Exploring and Understanding the Factors Affecting the Adoption and Continued Use of an Integrated Personal Health Record Application in Saudi Arabia
No full textExploring Variation and Change in Rijāl Almaʕ Dialect: A Study of the Phonological Variable (k) in Production and Perception.
No full textThis thesis investigates the variation of voiceless velar stop (k) within the Rijāl Almaʕ Arabic dialect, analysing its shift between the local variant [x] and the supra-local variant [k]. To achieve this, the thesis adopts a multi-dimensional approach, examining both acoustic and articulatory properties of (k) alongside patterns of sociolinguistic variation in its production and perception. Acoustic analysis, which includes auditory assessments, visual inspection of waveforms and spectrograms, as well as measurements of duration and rise time, indicates a clear tendency to replace the local variant of (k) with the supra-local variant [k]. However, the change is not limited to a simple binary distinction between local and supra-local forms; there are also intermediate variants present. These findings highlight the importance of acoustic analysis in understanding linguistic change.
Focusing on the acoustic characteristics of the local variant of (k), the results from F2 and COG measurements were not sufficient to definitively clarify its place of articulation. To address this limitation, an ultrasound tongue imaging study was conducted to compare the fricative realisation of (k) with six other voiceless fricatives and the velar stop /k/ as a reference. The results indicate a velar place of articulation as the target for the local fricative variant of (k), contrasting with previous suggestions that have classified it as either uvular [χ] or post-palatal [x̟]. The results further suggest that vowel context influences this articulation, however, the degree of this influence varies among speakers, highlighting the complex and speaker-specific nature of phonetic variability.
Building on the acoustic evidence, a third study explores the factors influencing variation in realisation of (k), focusing on both internal linguistic factors and external social influences. The results indicate that the shift toward the supra-local form is driven by younger females and those in more open social networks.
As for internal factors, while the supra-local variant [k] appears across all phonological environments, it is preferred in onset and medial positions as well as before back vowels. In contrast, the local variant is more restricted, primarily occurring before front vowels and in coda positions.
Finally, a Social Category Association Test (SCAT) study examines the relative sociolinguistic salience of these variants of (k) and points to the role salience plays in linguistic variation and change. The results confirm that the local variant of (k) is highly salient. Furthermore, the women leading the shift toward the supra-local form are also the most aware of these variants and their associated social meanings. These findings contribute to our understanding of the ongoing process of language variation and change within Rijāl Almaʕ, particularly the interaction between acoustic properties, social factors, and perception in shaping language variation
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