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Investigation of surface treatments undertaken prior to resin composite repair in clinical practice
Get PDFPh. D. ThesisIn dentistry the repair of a failed resin composite (RC) restoration is a recognized alternative to its replacement as it is less invasive and destructive to tooth-structure. There is minimal evidence available in support of a definitive repair protocol, limitation in understanding the mechanisms behind effectiveness of repair protocols and as such there is no clear guidance for clinical practice.
Therefore a questionnaire-based study was undertaken to explore how dentists manage fractured RC restorations in primary care dental practice in the UK. This information, along with the relevant literature surrounding the repair protocols was investigated. This then, informed the design of in vitro investigations to better understand potential repair protocols for RC as described by the outcome measures of shear bond strength (SBS), roughness, surface morphology and water sorption.
The questionnaire-based study suggested that 70% of dentists would repair RC restorations and they used a varied combination of pretreatments in the process of making a repair. The most prevalent repair methods were surface modification by the use of a bur, application of phosphoric acid or a bonding agent. The in vitro investigations undertaken as part of the study demonstrated differences in SBS level between repair protocols. The application of a bur followed by acid etch and a bonding agent led to the highest SBS. Differences in roughness and surface morphology appeared to affect SBS level. In contrast, water sorption and aging showed minimal impact on SBS level.
Conclusion: Dentists are currently repairing fractured RCs using different protocols. The in vitro investigations revealed surface treatments have different contribution to the SBS level and these differences in SBS may be explained by the accompanied change in roughness and surface morphology of RCs. The highest SBS level was achieved by the sequential use of bur, phosphoric acid and bonding agent.Kurdistan Regional Government-MH
A comparative study between public and private school provision in the Sultanate of Oman
Get PDFPh. D. ThesisThere has been recent interest in the role of private education as an alternative to state education in Oman. It has been presumed that private sector interventions will help enhance educational quality. This study aimed to examine the strengths and weaknesses of both government and private schools in Oman to explore these claims. The two systems are examined in terms of student’s academic achievements and the satisfaction of the main stakeholders – students, teachers and parents.
This study aims to fill the gap in school effectiveness research in Arab countries with a focus on Oman. A mixed-method approach was employed to answer the research questions. Both quantitative and qualitative data were collected in two stages. To generate empirical evidence of student academic achievement, a secondary analysis was performed on TIMSS 2015 mathematics assessment data for grade 8. In addition, a teachers’ job satisfaction survey was administered in public and private schools. In the second stage, in-depth semi-structured interviews were carried out with teachers and focus group discussions were employed with students to consider their perceptions of effectiveness and help triangulate the quantitative findings.
The results show that the achievement of private school students in mathematics is statistically significantly higher than that of their counterparts in government schools. This advantage persists even when the socioeconomic status of students is held constant. This finding is consistent with previous studies in different parts of the world. Participants’ views of their schools provide an insight into their perceptions of school effectiveness. In general, parents and students seem to prefer private schools, albeit for different reasons. While the parents’ primary reason for preferring private schools is academic achievement, the students’ main focus is on teaching quality and teacher–student relationships. Based on the teachers’ satisfaction survey, teachers in government schools are more satisfied with management, while teachers in private schools are more satisfied with their work conditions and parental involvement in their schools. Teachers in private schools are also more satisfied with their work as teachers. The qualitative data show most teachers prefer to work in the state sector, primarily because of the financial benefits offered by the government (salary, allowances, pension). However, there is no consensus on what makes a school more effective among the different school management participants.
The thesis makes an original contribution to knowledge of the education system in Oman and argues that there is scope for closer collaboration between private and government school systems and that these could learn from each other.Diwan of Royal Cour
The Narratives of Children Looked After: Promoting Academic Achievement and Supportive Teacher-Student Relationships
Get PDFD. App. Ed. Psy. Thesis.This thesis explores and generates new research about Children Looked After’s experiences in
education. It does this through qualitative evidence synthesis and narrative research. The rationale
for this research is to address Children Looked After’s low achievement in education. Whilst this
research does not emerge from a transformative paradigm, it does seek to centrally position the
experiences of a vulnerable and marginalised group with the hope of promoting change.
Chapter One: Qualitative Evidence Synthesis
This meta-ethnography explored ‘How do Children Looked After perceive their achievement in
education is supported or challenged?’. A model to guide professional practice supporting Children
Looked After’s achievement was generated. I suggest Children Looked After’s pre-care experiences,
whilst presenting challenge, provide them with a range of strengths and skills. Entry to care or
transition provides opportunity. Children Looked After may be supported to achieve by the
promotion of a sense of inclusion, security, agency and positive regard. These values are conveyed
through relationships. This model and its potential application are discussed in relation to statutory
processes and classroom practice.
Chapter Two: Bridging Document
This clarifies my philosophical position, justifies my decisions and demonstrates my understanding of
the theoretical underpinnings of my research. It is written in a narrative style using the metaphor of
a flower’s lifecycle.
Chapter Three: Empirical Research
A narrative research method was used to explore how Children Looked After may experience
supportive relationships with teachers within a mainstream secondary school. The data generated,
from unstructured interviews with four Children Looked After in England, was analysed both within
and cross-cases. Their behaviour, and its impact on teacher-student relationships (TSRs), dominated
narratives. My interpretation is supportive TSRs have less conflict. A second narrative suggested
supportive TSRs are developed and maintained when teachers takes actions perceived as caring.
Approaches to promote supportive TSRs coherent to these narratives, whose implementation may
be supported by an Educational Psychologist, have been suggested
Improving resource use efficiency and nutritional quality of grazing-based dairy production
Get PDFPhD ThesisThe dairy industry has received recent negative media coverage due to perceived poor sustainability, low animal welfare and high saturated fat content. However, evidence suggests that efficient, forage-based dairy production supports the environment and provides a nutritious product. While industrial dairy production has focused on yield as a measure of productivity, there is little research into optimising efficiency AND nutritional composition through farm management (such as breed, forage allowance, grazing strategy, etc.). Classic measures of production efficiency (kg feed/litre of milk) are not the sole priority in low-input systems, which also aim for improved health, fertility, forage conversion and milk quality. Holstein-Friesians were traditionally bred for high milk yields, which often correlate negatively with functional traits, such as fertility and health. For low-input and/or pasture-based systems, alternative breed choices are preferable, and UK dairy farmers have used several crossbreeding practices.
Milk fat composition is examined alongside farm management strategies (conventional, organic, low-input and pasture-based) to identify if there is a management practice, breed and/or individual cows that are most suitable to the farming system. Consistently, farms and cows that had higher proportions of forage in their diets produced milk with a higher concentration of nutritionally beneficial fatty acids such as, omega-3 and CLA9. Despite evidence that efficient cattle have less of an impact on the environment, the metric used for efficiency in pasture-based systems is just inputs vs outputs. This thesis explores the definition of efficiency and tries to find alternative metrics that include cow health, milk quality and productivity and finds breeds and cows that perform well under these conditions.
Researching the distinguishing factors of nutritional milk quality is key to sustainable production and addresses increasing media and scientific scrutiny regarding human health effects and ecological impacts of dairy products. Evidence of dairy farming systems that support the environment and provide nutritious food are essential to supporting UK dairy farmers.Seventh Framework Programme of the European Community for Research, Technological Development and Demonstration Activities as part of the Low Input Breeds Project (http://www.lowinputbreeds.org/home.html), the Sheepdrove Trust and ERA-NET SusAn that received funding for the SusCatt project from the Department for Environment, Food & Rural Affairs (DEFRA, UK) (https://www.nibio.no/en/projects/suscatt). &Faculty of Science, Agriculture and Engineering at Newcastle Universit
Identification and characterisation of Asparaginyl Endopeptidase expression and function in T regulatory cells
Get PDFPh. D. Thesis.The cysteine protease asparaginyl endopeptidase (AEP) is expressed in
antigen presenting cells (APCs) and is involved in activation of proteolytic
enzymes and antigen processing. Mice with a global deletion of AEP (Lgmn-
/-
) develop a lysosomal disorder characterised by the accumulation of
cathepsins but otherwise do not exhibit an immune phenotype. However,
an increased frequency of regulatory T cells (Treg) in the periphery has
been reported suggesting that AEP expression regulates Treg cell stability
through Foxp3 degradation. To study the induction of AEP expression in
mouse Treg cells, naïve and CD4+CD25+ T cells were cultured under Treginducing (iTreg) conditions which include TGF-β1. Freshly isolated CD4+ T
cells did not express any AEP while cells cultured under iTreg conditions
expressed the highest levels of AEP. To test the function of AEP in activated
peripheral Treg cells, a mouse model of melanoma was used. Lgmn-/- mice
with melanoma showed an increased frequency of tumour infiltrating Treg
cells compared to controls although tumour growth was similar between the
two groups. Next, the expression profile of AEP in human T cells was
investigated as the mechanisms regulating AEP expression and function in
these cells remain unclear. To study the induction of AEP expression in
human Treg cells, naïve and CD4+CD25+ T cells were cultured under iTreg
conditions. AEP was expressed in freshly isolated populations. Also, cells
cultured under iTreg conditions expressed the highest levels of AEP.
Blocking TGF-β1 signalling with a TGFBR-I inhibitor led to a decrease in
active AEP expression within the cells. Stimuli that could block AEP activity
were also tested. In keeping with previously published work, blockade of
PD-1 led to an increase of AEP activity levels in human lymphocytes. These
findings demonstrate that AEP expression is inversely regulated by TGF-β1
and PD-1 signalling in human T cells with implications for immunotherapy.Newcastle University
Research Excellence Academy awar
The role of corrective feedback and individual differences in second language learning
Get PDFPh. D. Thesis.The question of corrective feedback (CF) effectiveness in second language (L2) learning is still
under debate. Research has shown that a number of variables can play a role in determining
how a certain CF technique works for L2 learning. However, this research has raised more
questions that did it answer, especially with regards to how individual differences among
learners impact the way CF works for those learners. The present study is an attempt to further
our understanding of the topic. It aims at investigating the effects of recasts as one CF strategy
on learning English past tense by ESL learners and the extent to which learners’ individual
differences in anxiety, motivation and attitude might mediate these effects using a methodology
that has not been implemented by any other study in this respect. More specifically, the study
examined a) whether recasts lead to learner uptake/repair of past tense errors, and if so, whether
recasts characteristics (full vs. partial), the part of the target structure (regular vs. irregular)
mediate the rate of uptake/repair, b) whether recasts help learners improve accuracy in the use
of past tense, and if so, whether recasts effectiveness are mediated by the type of the target
structure and learners individual differences.
To this end, 40 participants at a lower-intermediate level in English took part in this study and
formed a recasts group (N=20) and a control group (N=20). Learners were involved in 5
treatment sessions with the researcher on one-to-one basis where they completed a number of
tasks designed to maximize the chance of producing past tense and receiving recasts when
errors occurred in its use in the case of the recasts group. Learners’ use of past test was tested
three times employing a pre-test, immediate post-test and delayed post-test design. For each
testing session, two measures were administered; an oral production measure and a written
production measure. To measure learners’ individual differences in relation to the three
constructs involved in the study, learners completed two questionnaires and their heart rate was
monitored using heart rate monitors to detect their anxiety levels.
The results demonstrated that recasts led to a very high rate of uptake following regular and
irregular past tense errors, however, the rate of repair was greater for irregular past errors than
the regular. Recast characteristics mediated recasts effectiveness with partial recasts generating
a higher rate of uptake and repair compared to full recasts. Results of the testing sessions
revealed that recasts helped learners improve their accuracy in the use of past tense, in
particular for the regular past tense in both the oral and written measures. Moreover, among
the three ID factors investigated in this study, only anxiety had an impact on the role of recasts
in the oral test only with the low-anxiety recasts group outperforming the control groups in the
delayed post-test. On the other hand, motivation and attitude measured by the four subscales
of the AMTB did not seem to impact the way recasts work on the learning of the simple past
tense. As such, the present study has fostered current perspectives on the role of CF and ID in
L2 theory and pedagogy.Hammah University in Hammah, Syri
Designing digital feedback technologies : exploring new forms of citizen engagement in public services
Get PDFPhD ThesisThis thesis is an exploration of the design of digital feedback technologies that promote new forms
of citizen engagement in the production of public services. It draws on public policy documents,
health and social care literature and socially engaged work within Human-Computer Interaction
(HCI) to inform the design of new digital feedback systems. Novel feedback systems were produced
to explore how digital tools may capture peoples’ views and opinions, while investigating citizen
participation in service innovation. It is an exploration and examination of the emerging public
sector spaces of coproduction and cocreation that focuses on how those facing marginalisation, such
as citizens with a learning disability or special educational needs (SEN), can come to have a voice
in care service design and delivery.
Three case studies were conducted with community partners: Case study one describes my work
as part of a steering committee collaborating with local government staff, voluntary sector workers
and parents of children with SEN in designing an online directory of services. Case study two
reports my collaborations with charity organisations to design a digital feedback system,
ThoughtCloud, for capturing and sharing the views and opinions of users of care services with a
learning disability. Case study three documents my work with young people with SEN in designing
and trialling a mobile application, Appraise, supporting them in shaping service provision through
novel evaluation processes. These technologies were designed in partnership with users of care
services, iterated through in-the-wild testing and evaluated through observation and stakeholder
interviews.
The contributions of this work include: learning that emphasises the importance of designing digital
feedback systems that are accessible and legible across diverse stakeholders; how the use of video
and audio media as feedback can alert us to the provenance of the data collected and create
evidence of citizen participation in consultation; the need for developing sensemaking tools that
can help surface narratives and support perspective sharing; and a description of the concept of
‘middle-out’ design as a means to practically framing the voluntary service sector design space
“Who is more intersectional than me?” An ethnography of the social locations of LGBTQ people from a Muslim background in Brussels, Belgium
Get PDFPh. D. Thesis.In this thesis, I apply an intersectional approach to the lives of LGBTQ people from a Muslim
background living in Brussels. I pay attention to the multiple interlocking axes of racialisation
and sexualisation that intervene in shaping processes of identification for LGBTQ people
from a Muslim background, the oppression they encounter, and the sites of potential
disruption of binarised norms that they inhabit. I present an analysis of ethnographic data
collected in Brussels between August 2017 and August 2018. Methods of data collection
included participant observation in spaces connected to the LGBTQ Muslim scene of the city,
30 semi-structured interviews with LGBTQ people from a Muslim background living in
Brussels, and a weekend of participatory theatre activities with nine LGBTQ people from a
Muslim background. The research was conducted in collaboration with Merhaba, an
organisation working with and for LGBTQ people from a migratory background in Belgium.
This thesis illuminates the specific social location occupied by LGBTQ people from a Muslim
background, beyond mainstream discourses that heavily rely on tropes of civilisational clash
between the West and the Arab/Muslim East on lines of attitudes towards sexual diversity and
gender equality. I argue that such an illumination not only allows for a better understanding of
the lived experiences of LGBTQ people from a Muslim background, but it also produces a
radical disruption of essentialising discourses of difference, and their materialisations at the
scale of the city. By focussing on the experiences and narratives of LGBTQ people from a
Muslim background, and the disruption that their social locations entail, this thesis contributes
to postcolonial approaches to the study of sexualities, to conceptualisations of
intersectionality and its applications in the European context, and to the study of geographies
of sexualities and geographies of race and ethnicity
Accurate Real-Time Framework for Complex Pre-defined Cuts in Finite Element Modeling
Get PDFPhD ThesisAchieving detailed pre-defined cuts on deformable materials is vitally pivotal for many
commercial applications, such as cutting scenes in games and vandalism effects in virtual
movies. In these types of applications, the majority of resources are allocated to achieve
high-fidelity representations of materials and the virtual environments. In the case of limited
computing resources, it is challenging to achieve a convincing cutting effect. On the premise of
sacrificing realism effects or computational cost, a considerable amount of research work has
been carried out, but the best solution that can be compatible with both cases has not yet been
identified.
This doctoral dissertation is dedicated to developing a unique framework for representing
pre-defined cuts of deformable surface models, which can achieve real-time, detailed cutting
while maintaining the realistic physical behaviours. In order to achieve this goal, we have made
in-depth explorations from geometric and numerical perspectives. From a geometric perspective,
we propose a robust subdivision mechanism that allows users to make arbitrary predetermined
cuts on elastic surface models based on the finite element method (FEM). Specifically, after the
user separates the elements in an arbitrary manner (i.e., linear or non-linear) on the topological
mesh, we then optimise the resulting mesh by regenerating the triangulation within the element
based on the Delaunay triangulation principle. The optimisation of regenerated triangles, as a
process of refining the ill-shaped elements that have small Aspect Ratio, greatly improves the
realism of physical behaviours and guarantees that the refinement process is balanced with
real-time requirements.
The above subdivision mechanism can improve the visual effect of cutting, but it neglects the
fact that elements cannot be perfectly cut through any pre-defined trajectories. The number of
ill-shaped elements generated yield a significant impact on the optimisation time: a large number
of ill-shaped elements will render the cutting slow or even collapse, and vice versa. Our idea is
based on the core observation that the producing of ill-shaped elements is largely attributed to
the condition number of the global stiffness matrix. Practically, for a stiffness matrix, a large
condition number means that it is almost singular, and the calculation of its inverse or the
solution of a system of linear equations are prone to large numerical errors and time-consuming.
It motivates us to alleviate the impact of condition number of the global stiffness matrix from the
numerical aspects. Specifically, we address this issue in a novel manner by converting the global
stiffness matrix into the form of a covariance matrix, in which the number of conditions of the
matrix can be reduced by exploiting appropriate matrix normalisation to the eigenvalues.
Furthermore, we investigated the efficiency of two different scenarios: an exact square-root
normalisation and its approximation based on the Newton-Schulz iteration.
Experimental tests of the proposed framework demonstrate that it can successfully reproduce
competitive visuals of detailed pre-defined cuts compared with the state-of-the-art method
(Manteaux et al. 2015) while obtaining a significant improvement on the FPS, increasing up to
46.49 FPS and 21.93 FPS during and after the cuts, respectively. Also, the new refinement
method can stably maintain the average Aspect Ratio of the model mesh after the cuts at less
than 3 and the average Area Ratio around 3%. Besides, the proposed two matrix normalisation
strategies, including ES-CGM and AS-CGM, have shown the superiority of time efficiency
compared with the baseline method (Xin et al. 2018). Specifically, the ES-CGM and AS-CGM
methods obtained 5 FPS and 10 FPS higher than the baseline method, respectively. These
experimental results strongly support our conclusion which is that this new framework would
provide significant benefits when implemented for achieving detailed pre-defined cuts at a
real-time rate
Potential for Growth Enhancement by Arbuscular Mycorrhizal Fungi in Potato
Get PDFPhD ThesisArbuscular mycorrhizal fungi (AMF) are important in natural and agricultural ecosystems to
provide and enhance nutrient uptake, particularly phosphorus. Potato is one of the most
important food crops globally in terms of total production and a phosphorus-demanding plant,
which grows in symbiosis with AMF. This field research investigates the influence of crop
management practices (fertiliser inputs and crop protection measures) and potato variety on
species abundance, the diversity and function of AMF in potato. The suitability of
mycorrhizal inoculants for growth enhancement in potato under specific management
conditions in the glasshouse was also conducted. Traditional root staining by ink and vinegar
method was used to quantify AMF colonisation along with three molecular techniques to
measure AMF species diversity and level of infection, including terminal restriction fragment
length polymorphism (T-RFLP), using AMF-specific primers FLR3 and FLR4 for LSU
rDNA amplification, Illumina MiSeq Next Generation Sequencing (NGS) using universal
fungal primers ITS1f and ITS2 for ITS region amplification and qPCR using AMF-specific
primers AMG1F and AM1 for SSU rDNA amplification. All three molecular techniques were
successful in nuclear ribosomal DNA region amplification.
The results show that organic crop protection management significantly enhances AMF
colonisation and the genetic diversity of the AMF community. The use of NPK fertiliser
along with conventional pesticides decreased AMF colonisation, the quantity of the AMF
gene, and diversity of the AMF community. The use of triple superphosphate in the field
showed a negative effect on AMF colonisation, the quantity of the AMF gene, and the genetic
diversity of the AMF community. The study did not demonstrate a strong relationship
between AMF colonisation and phosphorus uptake or potato tuber yield. NGS results showed
that potato colonised by native populations of AMF in the field were dominated by
Paraglomus. Potato variety had no significant effect on AMF abundance or the diversity of
the fungal community, but phosphorus uptake and potato tuber yield were significantly
affected. In the glasshouse experiment, Rhizophagus was the only genus detected in
inoculated plants, but colonisation was not correlated with phosphorus uptake and potato
tuber yield. This study demonstrated that natural populations of AMF could effectively
colonise potato in the field across a range of varieties but did not show any agronomic benefit
from higher levels of AMF colonisation, even under low P conditions