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Teaching English literacy skills to deaf learners in primary schools in eastern and central Kenya.
Get PDFThis thesis explores the experiences and literacy teaching practices of primary school teachers for deaf learners in Kenya. While several studies have investigated the development of literacy skills among deaf learners in developed countries, focus has primarily been on those who utilise speech thanks to access to newborn hearing screening and hearing devices. For this reason, this study specifically focusses on teaching of literacy skills to deaf learners who primarily employ sign language and often lack access to spoken language.
For this thesis, I utilised a qualitative research design and used semi-structured interviews, lesson observations, and document analysis as data-collection tools in seven primary schools for the deaf in Kenya. I conducted 24 semi-structured interviews with English literacy teachers and eight lesson observations. Furthermore, I collected documents such as lesson plans, textbooks, and curriculum design. I analysed data using reflexive thematic analysis in order to gain an in-depth understanding of teachers’ practices and experiences. I discussed the findings by considering the sociocultural approach to language teaching as well as previous literature on literacy skills development and deaf learners.
The main findings reveal how teachers’ practices support the development of deaf learners’ literacy skills. Specifically, the findings indicated that teachers focussed on specific language components and differentiated their methods of instruction in order to aid learners in reading and writing.
The other key finding is that teachers organised their classrooms space to increase opportunities for both human and material mediation. Additionally, regarding the use of resources in literacy lessons, this study revealed that teachers used visual resources to mediate learners’ understanding of written English, and they used print to mediate learners’ contact and engagement with written language. However, some instructional practices like where teachers dominated the literacy lessons limited the support deaf learners received in literacy lessons. Such findings revealed few opportunities for interaction, mediation, and scaffolding, which contribute to limited acquisition of literacy skills in English by deaf learners.
Continuing, even though teachers appreciated the support they received, their experiences revealed limited instructional knowledge as well as unsuitable curriculum and resources. Additionally, teachers viewed Kenyan Sign Language (KSL), limited language proficiency, and deaf learners’ challenges in reading and writing tasks as limitations to learners’ proficiency in literacy skills. Overall, the teachers’ experiences indicate a lack in deaf learners’ acquisition of appropriate tools, such as language and vocabulary knowledge, as well as limited human mediation of their literacy learning.
The findings suggest that teachers must create opportunities for interaction and scaffolding in literacy lessons by effectively mediating learning. Furthermore, findings also reveal a need for teachers to enrol in teacher professional development programmes in order to gain effective instructional skills. In addition, it is important to consider teachers’ pedagogical needs and contexts when developing programmes for practising teachers. Since deaf learners use KSL, teachers should be provided with information regarding KSL and literacy skills development, as well as how they can effectively utilise KSL in teaching literacy skills in Kenya
Translation-induced language change in the field of migration: a multilingual corpus analysis of EU legal texts and press articles
Get PDFThe terminology used in both legal and non-legal contexts to discuss issues related to migration is particularly critical given the consequences that the use of such language can have on people’s lived experiences and the ways they are perceived by others. It is therefore essential to understand how this terminology is evolving and the way in which it interacts across different languages. While the potential of translation to act as a propagating factor in language change across a range of language combinations has been demonstrated by previous research (e.g. Bisiada 2016, Malamatidou 2011, Amouzadeh & House 2010), this is the first sustained study investigating translation-induced language change in the field of migration terminology. This research aims to examine changes in migration terminology in English, French and Italian EU legal texts and press articles over a pre-defined time frame (1992-1998 & 2015-2018). The research focuses on the analysis of two purpose-built multilingual corpora, the EUMigrLaw Corpus and the MigrationInTheNews Corpus, created using the online corpus analysis software Sketch Engine. The EUMigrLaw Corpus is a multilingual parallel corpus made up of a range of binding and non-binding legislative texts produced by the EU, and the MigrationInTheNews Corpus is a comparable corpus containing a range of press articles from newspapers from the UK, France and Italy on the subject of migration. The research methodology, broken down into three sections of results and analysis, combines a range of both existing and innovative quantitative and qualitative corpus methods to detect and measure intralingual and interlingual variation and change in both corpora and identify potential sites of translation-induced language change in migration terminology. The key findings from this research reveal i) persistent widespread terminological variation across all three languages in EU legal texts in the field of migration and areas of terminological convergence among the languages being studied, suggesting the occurrence of translation-induced language change; ii) intralingual terminological variation in press articles in each language, with significant differences between the terminological trends identified in each language; iii) isolated examples of contact-induced changes originating in EU texts, before becoming de-terminologised and appearing in press articles. This study therefore provides a rigorous methodological approach to examining different types of terminological variation and change in migration terminology over time, revealing the potential and limitations of translation-induced language change in this specific context. This thesis consequently explores the significant legal and linguistic implications of its findings and considers subsequent avenues for future research
The effect of transcranial direct current stimulation concurrent with cognitive training on working memory
Get PDFBackground
Working memory plays a crucial role in higher-level cognitive functions such as reasoning, learning, and comprehension. It also serves as a predictor of academic achievement and professional success in individuals. However, working memory may decline with ageing and/or acquired brain injury, including strokes. Cognitive training can counteract cognitive decline, particularly when complemented with Transcranial Direct Current Stimulation (tDCS). TDCS can modulate neural excitability and enhance neuroplasticity, making it a promising tool for enhancing working memory when combined with working memory training. Nevertheless, the efficacy of tDCS combined with working memory training may vary among healthy adults and the elderly, with limited research focusing on acute stroke patients.
Method
In this project, I leverage between-participant designs to investigate the efficacy of combined tDCS and working memory training intervention for modulating working memory function in three distinct groups: healthy adults, elderly participants, and acute stroke patients. The initial phase of the project aims to explore the impact of various factors, such as the choice of tDCS setup (high-definition tDCS vs. bipolar tDCS), the experimental protocol (online vs. offline tDCS), and external variables (e.g., age, initial working memory capacity, and cognitive strategy), on the outcomes of the intervention. To achieve this, I administered one or more sessions of 2mA tDCS for 20 minutes along with a working memory task (specifically, the nBack task), simultaneously engaging both the storage and processing components of working memory. In the project’s second phase, I applied the insights gained from the initial phase to design an intervention specifically tailored for a group of acute stroke patients.
Results
In healthy young adults, I found that the application of a single-session high-definition tDCS, either online or offline with a working memory task, did not have a significant impact on performance. However, when bipolar tDCS was utilized, and individual differences were considered, there was a significant benefit for young adults with lower working memory capacity. This trend was also evident in older adults, where I observed that an individual’s initial working memory capacity played a pivotal role in the effectiveness of a combination of tDCS and working memory training over a short period.
Building upon these findings, I proceeded to investigate this specific setup, involving 20 minutes of anodal bipolar tDCS over the right dorsolateral prefrontal cortex, along with adaptive working memory training, in acute stroke patients, showing a working memory decline. In this context, I found that stroke patients with left-sided brain lesions exhibited notable improvements in working memory performance.
Conclusion
In summary, this comprehensive study underscores the notion that tDCS functions as a “state-dependent” intervention, showing discernible benefits for specific groups: healthy young adults with initially low working memory capacity who were given external strategy support, elderly individuals who are both older and have a low baseline working memory, and acute stroke patients with left-sided brain lesions. In the future, researchers should carefully take these factors into account and delve into the mechanisms underpinning the effectiveness of this intervention
Automorphism group of a Matsuo algebra
Get PDFAxial algebras are commutative, not necessarily associative algebras generated by axes, where axes are idempotents whose adjoint actions are semisimple and such that the product of eigenvectors is controlled by a specific fusion law. Matsuo algebras, defined using Fischer spaces and -transposition groups, are examples of axial algebras of Jordan type . In this thesis, we show that Matsuo algebras with almost never contain additional axes, and consequently, their automorphism groups almost always coincide with the automorphism group of the underlying groups of -transpositions. Furthermore, we identify all exceptions to this general rule in the irreducible case. Namely, we find three infinite series and an additional sporadic example of Matsuo algebras having extra axes and a larger group of automorphisms. In particular, for specific , we show that is isomorphic to a quotient of , and similarly is isomorphic to a quotient of . These are examples of what we call aligned pairs of groups of -transpositions. We use the information about the spectrum of the diagram of irreducible -transposition groups, provided in [HS21], to find all aligned pairs of irreducible -transposition groups. We conclude that, apart from the examples above, there is only one additional sporadic aligned pair
Effects of nutrient and exercise interactions on the components of energy balance
Get PDFObesity and overweight are rising worldwide. One common strategy to manage body mass is to modify physical activity levels. However, in most cases, the effects of increasing physical activity or exercise are not reflected in body mass changes, possibly due to the trigger of changes in the components of energy balance to counteract the energy deficit. Metabolically, it has been suggested that carbohydrate availability/metabolism (e.g., glucostatic, glycogenostatic or hepatostatic theories) could play a role in modulating the changes in the components of energy balance as a signal of energy availability. The aim of this thesis was to investigate how, from a metabolic perspective, dietary carbohydrates and physical activity/exercise interact in the short term to modulate energy balance components (such as energy expenditure, energy intake, and appetite).
Chapter 3 explored the short-term effects of replacing exercise energy expenditure with a high carbohydrate/low fat (HCLF) or a low carbohydrate/High fat drink (LCHF) on energy balance components. After the exercise energy expenditure was replaced with two different drinks, participants were studied across four days, where appetite, energy intake, activity- and total energy expenditure were evaluated. This chapter showed two novel findings - an increased cumulative activity energy expenditure and a decreased appetite for the HCLF treatment compared with LCHF condition. Therefore, it showed that a nutritionally different energy replacement post-exercise could lead to divergent responses on energy balance and appetite components.
Following these observations, Chapter 4 investigated the effects of a carbohydrate-fed (FEDex) versus an overnight-fasted (FASTex) exercise bout on the components of energy balance (i.e., energy intake, activity and total energy expenditure, appetite) and interstitial glucose metric across four days. Although no significant differences between the two conditions were observed, the study expanded the previously published data time frame, providing a more comprehensive understanding of acute and long-term energy balance studies. The findings suggest that both approaches could be used interchangeably as exercise strategies for body mass management.
Finally, Chapter 5 investigated the relationship between the habitual diet of individuals, considering both nutrients and energy intake, and their physical activity energy expenditure (AEE). The study was conducted using data from the UK Biobank cohort, where a Random intercept model was fitted from 52,643 participants. The study tested the predictability of two models - one including carbohydrate and energy intake, and the other including only carbohydrate intake - on the AEE levels. Although both models predicted around the same percentage of the variance (~2%) for AEE, the model that only included carbohydrates presented a better goodness of fit/complexity ratio according to the Akaike Index Criterion (AIC). These findings showed that habitual carbohydrate intake weakly but significantly predicts AEE levels in the UK Biobank cohort, suggesting that the effects of carbohydrates are not only due to their energy content but also their metabolic effects.
Overall, this thesis has provided new data suggesting that carbohydrate availability/metabolism around exercise/physical activity can affect AEE and appetite differently. These results fit some features of previous theories (e.g., glucostatic, glycogenostatic, and hepatostatic), although the observed responses are weaker than previously thought
Unravelling the effect of metal ions leaching from bioactive glasses on wound associated biofilms.
No full textChronic wounds (principally pressure sores, venous leg ulcers and diabetic foot ulcers) are a drain on global health services and remain a major area of unmet clinical need. Chronic wounds are characterised by a stable and stubborn bacterial biofilm (densely aggregated colonies of bacteria encased by a matrix of extracellular polymeric substances (EPS)) which hinders innate immune response and delays or prevents wound healing. Bioactive glass (BG) fibres doped with antimicrobial metal ions can offer a promising treatment for chronic wound infections.
In this thesis, firstly, an existing partial differential equation (PDE) model of a chronic wound infection is explored and adapted to investigate the combined antibacterial and wound healing effects of metal-doped BG fibres. From solutions, it was observed that the bacterial infection must be eradicated for a chronic wound to heal successfully. Accord- ingly, the development and characterisation of BG fibres doped with the antimicrobial ions, silver and copper, was next considered to investigate their antibacterial/anti-biofilm properties.
Anti-biofilm studies using the bacteria Pseudomonas aeruginosa & Staphylococcus au- reus demonstrated that treatment efficacy depended on the species used. Additionally, treatment was more effective against single-species biofilms compared to dual-species
Recycling the anode from electric vehicle lithium ion batteries for a circular economy
Get PDFLithium ion batteries are a vital part towards a decarbonised future. However, contained within are materials of critical importance, these include: cobalt, nickel, lithium, phosphorous and graphite (both synthetic and natural). Recycling of lithium ion batteries is essential to both ease the pressure on these unstable feedstocks and to ensure lithium ion batteries are sustainable. An often overlooked critical material within industry is graphite. This is due to the current economically low value of the material, however it’s monopolised supply chain and large greenhouse output warrants the case for graphite recycling. Another sentiment for graphite recycling is the specialist grade required for lithium ion batteries, requiring many energy taxing processing steps to create spherical, pitch coated particles for the anode. Academic research on graphite recovery mainly focuses on the extraction of graphite for use in alternative applications despite it being the active anode material in the vast majority of lithium-ion batteries. This is derived from the concept that use within a battery induces significant deterioration, including particle cracking and exfoliation.
Within this thesis, the quality of anode material recovered from cells of various states of health will be analysed in order to determine whether this material could act as a future source for battery-grade graphite. After which, a method to reclaim and reuse this graphite
will be developed.
Cells used within this work include quality control rejected, Envision AESC, first generation lithium ion pouch cells, and used (to various states of health) end of life lithium ion pouch cells obtained from a first generation electric Nissan Leaf.
The findings show that under normal and over-normal use, the graphite shows no substantial ageing. Degradation on the anode primarily occurs via solid electrolyte interface growth, metal deposition and particle disconnection. These factors can be easily addressed by recycling, rejuvenating and re-coating the anode. Therefore further focus was given to establishing a sustainable, quick and cost effective technique to extract and reuse the graphite for electrochemical use.
The difficulty in recycling graphite lies with the poly(vinylidene difluoride) binder. Poly(vinylidene difluoride) lacks solubility in non-harmful solvents making it difficult to separate the graphite from the other anode components. Within this work, it was found that when a discharged cell is dismantled, trace amounts of lithiated graphite remained in the anode. This lithiated graphite will react with water to produce hydrogen when submerged in water, which creates localised area of heat and pressure that can cleave the active material away from the current collector. The technique requires only water and its efficiency can be altered by increasing the time the anode is exposed to air. With increased air exposure, lithiated graphite will react with the moisture in the air and reduce the amount of hydrogen gas produced when submerged in water, decreasing the effectiveness of the delamination.
After delamination, the copper current collector was left bare and ready to collect, although with an oxidised surface. Anode active material (containing the graphite) could also be collected as large sheets. Lithium could be extracted from the delamination solution using sodium carbonate and phosphoric acid. As a proof of concept, (0.14 g of Li2CO3 and 0.34 g of Li3PO4 were extracted from an end of life anode weighing 13.5 g.
Water delamination also cleaned the graphite surface of most contaminates, although the poly(vinylidene difluoride) binder and metal contamination still remained. Annealing to 500 ◦C removed the binder and produced graphitic material similar to virgin batterygrade
graphite. This recovered graphite was used to create second-life anodes, whose electrochemical performance was tested. Half cell performance showed that graphite recovered from a cell with only 30% of its original capacity could perform close to the theoretical capacity of graphite after water delamination and annealing. This demonstrates that End-of-Life lithium ion batteries can provide high-performing battery-grade graphite,
helping to secure future supplies of this critical raw material and alleviating concerns over future accumulation of battery waste.
Water delamination was ineffective after exposing the anodes to air for more than four weeks. It was found that the use of acids allowed for an extended period of delamination that provided graphite of similar quality.
Up-cycling of the graphite material was attempted via delamination within colloidal silica. Here, nanoparticles of silica would coat the graphite allowing for increased capacity during second life use. However, the deposited silica particles were too large to be electrochemically active and therefore future avenues for optimising this procedure are suggested
D-Arabinan hydrolysis and its roles in mycobacteriales biology
Get PDFMicrobial arabinogalactans are rare in nature, restricted to the order Mycobacteriales, where it plays a critical function covalently tethering the exterior mycomembrane to the inner peptidoglycan sacculus. To date, no enzyme or group of enzymes had been discovered which were capable of the breakdown of this complex polysaccharide. In work prior to this thesis, our group reported the first such group of enzymes in gut resident bacteria.
This thesis explores the functional diversity of two new enzyme families, GH183 and GH172 which are conserved across Mycobacteriales species. In the first chapter, endogenous homologs of the GH183 enzyme family in Mycobacterium tuberculosis and it's non pathogenic relative Mycobacterium smegmatis are characterised using biochemical and structural methodologies. In the second chapter, a GH172 enzyme is demonstrated to be involved in a putative recycling locus in the human pathogen Nocardia brasiliensis. Finally, in the third chapter, we explore homologs of the GH183 enzyme which appear to be involved in intraspecies competition. In summary, this thesis reports on the discovery of two new enzyme families and their roles in the homeostasis of the Mycobacteriales cell wall, with significant implications across mycobacteriology, including in treatment of high priority mycobacterial disease such as tuberculosis
FDEM analysis of shale anisotropy and its effect on EDZ fracturing in deep buried tunnels
Get PDFFractures form and propagate in the excavation damage zone (EDZ) due to underground excavation, degrading the rock's mechanical properties and permeability, and resulting in excavation problems such as collapse, seepage, rock burst and large deformations. In addition to affecting the choice of excavation method and design of supporting structures in underground engineering projects, understanding the formation and evolution of the EDZ, especially its fracturing mechanism, is also an important assessment index for the design of permeability sensitive excavations (such as hydroelectric power generation stations or nuclear waste repositories). However, the study of the fracturing mechanism and fracturing conditions of the EDZ still remains as an open topic, especially under shale formation. As one of the most encountered rocks during underground construction, shale poses many geotechnical problems due to its special properties (e.g., anisotropic behaviours, creeping and self-sealing). Shale is difficult to study because of its complex mechanism response. Shale matrix strength and fracture mechanism are affected significantly by bedding planes with lower stiffness and cohesion. This research adopted the finite discrete element method (FDEM) to create anisotropic shale models in ABAQUS.
Based on FDEM laboratory-scale models, fracturing mechanics, fracturing behaviour, and brittleness of shale have been studied from a microscopic perspective with taking shale anisotropy into account. Three failure modes for shale in uniaxial compressive test have been identified, in terms of tensile splitting (T-S), bedding plane delamination (B-D) and shearing through matrix (S-M). Two novel new brittleness indices, in terms of BIf and BICD, have been proposed in this study to help researchers to assess shale frac-ability and provides an easy approach to evaluate rock brittleness based on uniaxial compression test. In addition, an empirical relationship has been proposed in this study to predict the tensile strength
A systematic approach to evaluating operations of virtually coupled trains
Get PDFRailway transport holds prominence as a viable alternative to road and air modes. With the demand for rail expected to continue its upward trend, stakeholders are seeking innovative solutions to boost rail traffic volume. Virtual Coupling (VC) has been proposed as a concept that enables trains to run closer than existing operations. This can be achieved in a way that two or more trains become engaged with each other so much that they move like a single unit via synchronous acceleration and braking. VC operations, when deployed, are expected to increase line capacity. However, rail lines are so complex that capacity enhancement is not simple and straightforward. Some studies and projects have conducted research on VC, but a systematic approach to evaluating the capacity enhancement of VC operations has not yet been developed. This study has made an original contribution to VC research by developing an evaluation framework for assessing the VC operational performance.
As a step of concept exploration, VC was defined from an operations perspective. The study categorised VC operations from two viewpoints including convoy formation and safe distance principle. Two types were defined through the convoy formation: In inter-consist one, two or more trains are virtually coupled with each other, whereas in intra-consist one, one train is split into smaller sub-trains. From the viewpoint of braking principle, VC operations were defined on the basis of either Absolute Braking (AB) or Relative Braking (RB).
The study has defined four basic operational scenarios depending on where coupling and/or uncoupling occur: at stations or around junctions and then, has developed a simulation architecture to assess capacity performance for these scenarios. The simulation results indicate that under ideal conditions, VC on RB can deliver a capacity of 240 train per hour for a plain line, but this performance is confined by switch processing times for the scenarios including diverging or converging route. VC on AB deliver a capacity ranging from 60 to 70 train per hour for all the scenarios. Also, it was found that intra-consist operation reduces energy use and travel time, especially for express high-speed train services. In addition, the study has investigated influencing factors on VC performance by conducting sensitivity analysis. The following factors were found effective on capacity performance and important in creating a VC operational plan: braking capability, adhesion, fleet heterogeneity, station layout and platform length, relativity index, number of trains in a convoy, virtual interlocking type.
The evaluation framework, developed by this study and presented with the IDEF0 notation, is the first one that creates a systematic approach to evaluating VC operations on a rail line against its existing performance. The framework has been demonstrated through a case study. The London Waterloo to Surbiton line section was analysed over a VC operational plan of nine scenarios with varying safety levels and convoy types. The simulation results indicate a potential capacity increase of two to four times, contingent on fleet expansion with additional 40 to 80 stocks. However, delay propagation is an issue as per deterministic perturbation scenarios, suggesting reducing convoy sizes and increasing time intervals between them as a resilience strategy
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