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Liquid Refractive Index Measurements using a Terahertz Vector Network Analyser
Get PDFA lack of coherent sources has led the terahertz region of the electromagnetic spectrum to remain relatively unexplored as compared to its neighbouring frequencies. Over recent decades the development of these sources along with coherent detectors has led to the rapid development of terahertz technologies. To characterise and use materials within this region a database of material knowledge must be built up.
This thesis aims to outline various methods of material characterisation using a vector network analyser. It considers and overcomes issues to do with data collection using the vector network analyser within the frequency domain and secondly problems due to strong absorptions associated with water based samples within the terahertz region.
Two novel cuvette measurement methods are presented which use rotational stages to enable the vector network analyser to extract material data. A self-referencing technique rotating the test liquid and another self-referencing technique using a known refractive index reference liquid are shown. The latter is a fast and precise measurement technique which is as accurate as the known reference and could potentially be used for in-flow testing.
The use of paper at terahertz frequencies is explored with a particular interest in the use of paper for sensing. A range of metamaterial designs are simulated, fabricated and tested to develop a metamaterial device which can be used for liquid sensing. It was found that soaked filter paper in contact with the metamaterial surface is able to distinguish between different soaking liquids.
Serum samples of seven different tumour markers have been tested to determine if the metamaterial in contact with serum soaked filter paper could provide an indication of tumour marker concentration. The outcome of this feasibility study suggested possible relations between absorption peak position frequency and marker concentration for five of the seven tested markers
“A Tissue, A Tissue, It All Falls Down”: A Review of the Impacts of Covid-19 on the English Criminal Court System Between March 2020 and March 2021
Get PDFThe COVID-19 pandemic brought the criminal court system to a grinding halt on 17 March 2020, as it did much of life in England; this was the starting point for drastic and sudden change across the criminal court system. There were three primary categories of change: increased the delays in criminal proceedings; wide-ranging changes to the use of live links and the administration of remote justice; and a revaluation of approaches to open justice. This thesis addresses each of these categories in turn, evaluating the degree of impact they have on the actors involved in these matters – the defendants, victims, and even legal professionals. It does this by using a range of primary sources, such as Twitter posts, the Courts and Tribunals Service court data, caselaw and legislation, alongside the use of secondary sources, including reports from Non-Governmental Organisations, contemporary news articles and blogs, and academic commentary. The thesis finds that COVID-19 resulted in widespread and detrimental changes to the criminal court system in England, and that recovery from them is lacking. This has had a directly negative impact on the experiences of actors involved in that system. Many of the detrimental changes were an exacerbation of flaws in an already overburdened and vulnerable system. The importance of these changes cannot be overstated, nor can the need for them to be remedied. Ultimately, without attention, and funding, being given to resolving the impacts that have developed as a result of COVID-19, there may be implications for the very integrity of the criminal court process in England
The Impact of Online Teaching and Learning on Faculty and Students at Higher Education Institutions after Covid-19 pandemic.
Get PDFThis thesis investigates the satisfaction of staff and students with online teaching and learning during the single delivery of online courses, as well as the consequences of relevant lessons, based on the Covid-19 experience. Inductive and deductive methodologies have guided this work. With the deductive technique, I employed quantitative data in addition to the literature review to assess the hypotheses behind this study, while with the inductive approach, I conducted interviews from which themes emerged.
In this thesis, I investigate the faculty's involvement in online teaching and learning during the Covid-19 epidemic, the effect of institutional support on faculty satisfaction, and the effect of online teaching and learning flexibility, communication, and participation on student satisfaction. I add to the continuing conversation on OTL by investigating how faculty members handled and adapted to the crisis during the Covid-19 outbreak, using the theories of crisis management, change management, and satisfaction theory as the framework for my inquiry. My results indicate that the pandemic expedited the adoption of online teaching and learning in Higher Education Institutions, however the post-pandemic future remains uncertain. The conversations emphasise how the pandemic may be utilised as a learning experience and how institutions will need to tailor this experience to enable online teaching and learning continuation after the epidemic. The research will provide HEI executives, practitioners, and policymakers with knowledge about the consequences of digital transformation in education
The influence of environmental heterogeneity and sexual selection on the genome of the Brown Booby (Sula leucogaster)
Get PDFSexual selection has been a central theme in evolutionary biology since the time of Darwin, but even though field studies have shown that sexual selection on focal traits can vary across populations and over time, we rarely understand why. In some mating systems, ornamental traits (e.g., colorful displays) are thought to be condition-dependent signals that reveal the genetic characteristics and the current state of the bearer, acting as honest phenotypic cues through which the quality of potential mates can be assessed. In the present thesis, blood samples of brown boobies (Sula leucogaster brewsteri) were collected from males, females and offspring in three colonies with different environmental conditions in the Pacific Coast of Mexico. I used a customized ddRAD sequencing approach to generate genome-wide SNPs to investigate the genetic variability associated with phenotypes subject to sexual selection in brown boobies, and how selection of such traits might vary in the presence of environmental heterogeneity.
In chapter 2, I examined the mate choice and extra-pair paternity of brown boobies under different environments. A parentage analysis was performed to determine the rate of extra-pair paternity (EPP), and measurements of heterozygosity and genetic similarity were used to find correlations of genetic quality and ornaments used during courtship. Additionally, the genetic quality of the individuals was compared against measurements of colour and body mass which are traits that could be subject to sexual selection. The results suggest that variation in skin colour is an honest indicator that reflect the heterozygosity and dissimilarity of brown boobies, and that levels of EPP are very low and that it is potentially influenced by local environment.
In chapter 3, I investigated the distribution of the genetic diversity will and the correlation with geographic distance and to the environmental variables like sea surface temperature (SST) and primary productivity (PP) in each colony of brown boobies. I also measured the genomic structure, gene flow and demographic history of brown boobies and explore the possible implications in the context of mate choice. I found that brown booby populations in the Eastern Pacific seem to be highly differentiated and genetically isolated regardless of their relatively proximity. Additionally, a small but significant correlation between environmental variables and the genomic variation was found, which could be subject to natural or sexual selection.
In chapter 4, a specific sampling scheme of my genomic data was applied to characterize different signatures of selection (genome-wide selection component analysis framework). Two genome-wide selection scans were used to detect outlier loci under putative positive selection by comparing allele frequencies between males, females and offspring. The genomic regions near to such outlier loci were extracted to investigate the biological function (using Gene Ontology terms) associated with such regions. By comparing different groups of individuals based on their sex, living stage and geographical location, different types of selection were identified in brown boobies, though the caveats of the used framework are discussed. Various biological functions appear to be associated with different forms of selection simultaneously, like in the case of sex-specific viability, gametic and natural selection. However, the biological functions like growth, rhythmic processes and locomotion seems to be associated specifically to sexual selection.
Finally, I revisited the main results of my thesis in chapter 5 and discuss impact of my findings in a broader context
‘Bodies of water’: The Ecofeminist Water Poetry of Jorie Graham and Alice Oswald
Get PDFThis thesis explores the water poetry of Jorie Graham and Alice Oswald as an ecofeminist response to the climate breakdown. I begin by situating Graham and Oswald’s work in the broader contexts of feminism, using foundational feminist voices to understand how female identity is formed, with a particular focus on the role of naming. I show how the notion of a coherent, lyric speaker, able to straightforwardly address that which they describe, is challenged by the ecopoetic understanding that we are inextricable from nature, and that this assumption of wholeness comes under particular strain in the context of the late-stage climate disaster.
By engaging with their predecessors in the genre of nature poetry, Graham and Oswald inhabit and depart from these foundational ways of being in and writing about nature. Graham continues the transcendentalist respect for nature but rejects the idealised pastoral ‘retreat’, and complicates the transcendentalist ideal of self-sufficiency. Oswald writes largely against the Romantic Egotistical Sublime, and favours poetry which attempts to speak from within nature. Through an extended exploration of Oswald’s Dart, I show how human identity is shaped by rivers, and how our dependence on this aqueous element is intertwined with our histories of place.
Through this in-depth exploration of water in Graham and Oswald’s poetry, I show how they both reflect human dependence on water and our interconnected identity as part of a wider whole, and how the climate emergency necessitates a wider acknowledgement of this multiplicity of identity
Shifting chronotypes: Sleep patterns among adolescents living in industrial and pre-industrial environments
Get PDFUsing biosocial, cross-cultural, anthropological perspectives, this research compares sleep patterns of adolescents (aged 11-16) in one industrial society and two non-industrial societies in Mexico to help unravel evolutionary and cultural aspects shaping contemporary adolescent sleep. Specifically, this study examines whether the shift in the adolescent sleep-wake cycle reported among industrialized populations is replicated in non-industrialized societies with little access to electronic and/or electrical devices and whether sleep sufficiency is greater in non-industrial settings.
Adolescents (n=145) wore Motionlogger Micro Watch units for 24 hours over ten days and completed sleep diaries to obtain sleep measurements of sleep timing and duration. Data about the participant’s sleep environment were assembled through semi-structured interviews and ethnographic observation. Information from the Pubertal Developmental Scale was used to discuss changes in adolescent sleep. The between-population variation in sleep measures was investigated by fitting different types of three-level models.
Pubertal development was associated with a delay in sleep timing during non-school days, and this was significant in all but one of the non-industrial sites. Sexual maturation was also associated with a shorter sleep duration during school nights, but no such association was identified for adolescents in the industrial site. Short sleep quotas were as prevalent in non-industrial-site teenagers as in their industrial-site counterparts. Sleep timing and duration were more responsive to natural light-dark cycles and social sleep in non-industrial settings.
Results provide novel evidence of flexible sleep-wake patterns in adolescents and highlight the influence of social activities on the expression of human sleep behaviour. Adolescent circadian plasticity might result from life-history trade-offs related to the switchover to future investment in reproduction. Circadian plasticity might have been advantageous in ancestral human environments, benefitting individual and group fitness. Any sleep interventions to improve contemporary adolescent wellbeing should address individual and community needs to develop more equitable and effective health policies and practices
Towards single-photon emission from zero-wave vector Rydberg polaritons in thermal caesium
Get PDFThis thesis presents the design, modelling and preliminary experimental setup of a deterministic single-photon emitter scheme. It relies on storing a three-beam zero-wave vector Rydberg polariton in a caesium thermal vapour through dressed-state electromagnetically induced transparency (EIT).
EIT was experimentally studied through 6S_1/2 -> 6P_1/2 -> 6D_3/2 in room temperature thermal caesium, and data was compared to an analytic model derived for weak probe velocity-averaged hyperfine absorption. Peak heights and widths were over-estimated because of a uniform intensity beam assumption and the lack of a strictly weak probe in the experiment. Along with fluorescence data from the 7P_1/2 -> 6S_1/2 decay at 459.4 nm, EIT was shown to maximise the upper state population whilst simultaneously reducing the line centre probe absorption.
Dressed state three-level EIT is then derived from the four-level ladder Rydberg excitation scheme with laser parameters calculated for a 2pi x 1 GHz dressed state Autler-Townes splitting. The corresponding probe absorption was simulated for continuous wave and pulsed STIRAP excitation demonstrating expectedly weak Rydberg EIT. Polarisation spectroscopy was investigated for probe beam frequency stabilisation yielding a steep slope dispersive error signal. Finally, a bespoke hexagonal vapour cell was designed that minimises astigmatism aberrations from focusing beams across tilted planar interfaces. Dimensioned photographs of the fabricated cell display its readiness for use in future three-beam Doppler-free experiments
An analysis of the roles and activities of stakeholders in reviving and promoting the disrupted traditional cultural heritage of the Kazakh people
Get PDFABSTRACT
Following the dissolution of the USSR (1988-1991), all Central Asian countries proclaimed their independence including Kazakhstan in 1991. With great freedom came great responsibility as the newly emerged countries had to rebuild and reinvent themselves to regain their political sovereignty and cultural identities. While much of the research into the role of cultural heritage in the postcolonial revival has been undertaken in the Africa and Commonwealth countries, comparatively little investigation has been carried out on the area of Central Asia. Representative of the region, Kazakhstan with its multifaceted history, intricate geopolitical position, disrupted heritage and contested demographics, is worthy of particular attention.
Before the Russian expansion (1731) the Kazakh people were nomads who peregrinated to the north in the summer and to the south in the winter with their herds of domesticated animals. However, Russian colonial and Soviet collectivisation policy disrupted not only the Kazakh nomadic lifestyle but also their traditional cultural heritage. In order to deepen understanding of this history of cultural loss, reconstruction and preservation, this research examines the main features of the nomadic cultural heritage of the Kazakh people before and after the Russian/Soviet rule.
Two aims direct this research: to assess the impact of the Russian colonisation of the Kazakh steppe on the traditional nomadic cultural heritage of the Kazakh people, and to analyse the roles and activities of identified stakeholders in reviving, preserving and promoting this heritage.
Efforts to protect and promote cultural heritage require the engagement of various stakeholders. However, no extensive research has concentrated on the role and activities of stakeholders in the preservation of cultural heritage in postcolonial ii
countries. Therefore, this research aims to examine the perceived roles of the government, international organisations (UNESCO), and non-governmental organisations in the protection of the cultural heritage of the Kazakh people. These stakeholders have significant but different perspectives concerning cultural heritage. The research shows that main motivation for the Government of Kazakhstan to revive and preserve its traditional cultural heritage is to build a national identity. The demographic composition of Kazakhstan posed a dilemma as the countryʼs government had to choose how to ethnically, culturally and ethnolinguistically define Kazakh identity as paramount without alienating other ethnic groups living in Kazakhstan.
This research adopts a qualitative method. Interviews and textual analysis are the main data sources, to which thematic analysis has been applied in order to identity common themes and concerns. A multi-sited ethnographic research takes place in Qyzylorda, Oral, Almaty and Astana/Nur-Sultan cities where the researcher includes representatives from practitioners, governmental organisations, international organisations and non-governmental organisations responsible for the development and preservation of the cultural heritage of the Kazakh people. The present research applies several conceptual frameworks including Said's "Orientalism" (1978), collective memory, and Nora's (1989) concept of "sites of memory”. This research contributes to the academic literature associated with the future work and policies of international organisations, NGOs and government authorities in developing mechanisms and frameworks to support the revival and development of identities and cultural heritage in Kazakhstan
The Development and Applications of Novel Bioengineered Human Epithelial Tissue Models and the Role of Tissue-Specific Fibroblasts
Get PDFEpithelial tissues are critical for survival as they represent the first line of defence between the body and the external environment. Arising from all three germ layers, epithelia are a diverse group of tissues which line the internal cavities and cover most of the body and organ surfaces. Therefore, there is a high demand for epithelial tissues for research and testing purposes. However, supply is limited, and most epithelia-based studies rely upon simplistic 2D cultures and animal models which are subject to a number of limitations including variability, major ethical considerations and difficulties in relating findings back to humans due to structural and functional differences.
Epithelial tissues share a common, highly conserved structure comprising a surface epithelium which is supported by an underlying basement membrane and fibroblast- populated connective tissue compartment. However, the importance and complexity of this subepithelial compartment is often overlooked.
The advent of advanced 3D cell culture technologies and tissue engineering techniques has enabled the development of tissue-like constructs in vitro. Utilising a bottom up approach whereby human fibroblasts seeded into Alvetex® Scaffold are able to deposit endogenous extracellular matrix components and generate a dynamic stromal environment, we have successfully generated a range of novel bioengineered epithelial tissue models. Through extensive characterisation, we have shown that our respective tissue models demonstrate structural morphology resembling the architecture of native human skin, oral and nasal mucosa. Due to the fundamental anatomical principle that structure is related to function, the ability of these models to mimic the structure and thus function of their in vivo counterparts is critical to their success.
We hypothesise that signalling from fibroblasts within the subepithelial compartment is critical to the differentiation of the overlying epithelium and propose that these tissue engineered models provide valuable platforms for a range of both industrial and academic applications
PERFORMANCE INCENTIVES IN THE TAKAFUL INDUSTRY: AN EXPERIMENTAL INVESTIGATION
Get PDFThe takaful industry offers customers insurance products judged to be compliant with Islamic law, in return for payments into insurance funds managed and invested by a takaful company henceforth called the ‘operator’. Contracts provide for a transfer of risk from policyholder to insurance fund, using a hybrid of two standard organisational forms: a) the stock insurance model, where the operator has control and ownership of residual funds, and b) the mutual insurance model, where policyholders enjoy control and ownership of residual funds. In the takaful industry, there is a complete separation of ownership of policyholder residual funds from their control, which rests solely with the operator. Policyholders are therefore in a classic principal-agent relationship with the operator, with obvious potential for agency costs. A case can therefore be made for regulation of the industry, to protect the interests of policyholders. One way to reduce agency costs is by appropriately designed monetary incentives to the operator. Policyholders are unable to act to control the operator’s compensation or decisions. A regulator is therefore essential to act on their behalf, as they are not represented and not properly taken account of by shareholders. Three forms of Shariah-compliant compensation, in order to study economic incentives for the operator to efficiently perform three broad categories of tasks, involving decisions on the size of the pool of policyholders, on cost control, and on investment of technical reserve. The three forms are sales commission (wakalah), sharing of investment profit (mudarabah), and sharing of residual funds (ji’alah). All three forms can be observed in practice, sometimes in concert, though in some regulatory jurisdictions some of them have been prohibited or restricted. The aim of the study is to provide empirical evidence on the efficiency and equity of the takaful organisational form. A laboratory experimental approach is chosen for the research design in order to avoid problems of non-availability and endogeneity of data. The experimental subjects were students from Durham University, incentivised in accordance with the research design through money payment. The data is analysed using Statistical software for data science (STATA). The implications of our findings for regulators show that only ji’alah offers an efficiency gain to the agency as a whole, the evidence in favour of including wakalah in a hybrid contract is weak. And there is no clear evidence of ‘gifts’ being reciprocated by better alignment of operator decisions with the welfare of policyholders
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