5357 research outputs found
Sort by
Modelling the dynamics of the upper ocean in the Eastern Tropical Pacific and its interactions with the tropical atmosphere
Get PDFPh. D. Thesis.The physical behaviour of the central and eastern tropical Pacific regions is characterized
by a complex variety of multi-scale interacting processes. The Madden-Julian Oscillation
(MJO) is the primary mode of intraseasonal variability in the tropical atmosphere. Although
convection, together with related cloudiness and precipitation, tends to dissipate east of the
180º meridian, the MJO wind signal continues to progress eastward across the eastern
Pacific and South America and into the tropical Atlantic.
This research explores numerically the response of the upper ocean in the central and
eastern tropical Pacific regions to MJO forcing. We use a global, intermediate resolution
configuration of the Nucleus for European Modelling of the Ocean (NEMO) framework
version 3.6, referred to as ORCA1-LIM3, forced with daily atmospheric forcing from the
Coordinated Oceanic Reference Experiments (CORE) dataset version 2, for the period
1990 to 2000.
The results show a strong influence of the MJO on temperature, salinity, zonal currents,
and vertical currents in the first 300 m of depth, particularly at the equator. The
intraseasonal wind is the key forcing factor that modulates the impact of the MJO. This is
except for the temperatures at the mixed layer depth, the halocline, and the pycnocline, in
the regions of the Central American Pacific coast and the southwestern Mexican coast
where the influence of the MJO can be observed even in the absence of intraseasonal wind
forcing.
The impact of the MJO on the ocean's internal intraseasonal variability is analysed in the
case of tropical instability waves. We show that the barotropic and baroclinic conversion
terms that control the eddy kinetic energy levels in the region vary in magnitude with the
phases of the MJO. These results have ramifications for understanding ocean intraseasonal
variability, which is a critical step towards improving our ability to make more reliable
mid-range ocean weather and ocean climate forecasts for the region.Ministry of Science, Technology, and Communications of Costa Ric
Alpha-synuclein post-translational modifications and abnormal network oscillations in Lewy body dementias
Get PDFPh. D. Thesis.Lewy body dementias (LBDs) are age related neurodegenerative diseases
characterized by the presence of abnormal alpha-synuclein (αSyn) inclusions termed Lewy Bodies (LBs) and Lewy Neurites (LNs) and represent the second most common form of neurodegenerative dementia after Alzheimer’s disease. LBDs are progressive pathologic conditions with variable clinical signs and symptoms including dementia and abnormal neuronal network oscillations, with no currently available treatment. The interaction between αSyn post-translational modifications (PTMs) and neuronal dysfunction is a core concept in LBDs. Accumulating evidence shows that, αSyn PTMs, such as, phosphorylation, ubiquitination and nitration, are events that occur in the context of synucleinopathies. I hypothesised that these PTMs lead to the formation of toxic/aggregated forms of αSyn that causes neuronal dysfunctions/death and impair
neuronal network oscillations. The aim of this thesis was to Identify the PTMs of αSyn,
analyse their distribution in LBDs, correlate them with the distribution of parvalbumin expressing interneurons in in post-mortem brain tissues of LBD patients, and analyse its links with mitochondrial dysfunction and neuronal network impairments. Using,
electrophysiological and immunohistochemical protocols in selected cases that fulfilled the neuropathological criteria for LBDs and control cases, sourced from
Newcastle Brain Tissue Resource (NBTR), and Transgenic A30P and control C57BL6 mice from comparative biology centre (CBC), I found that aged A30P mice had greater
sensitivity to the mitochondrial inhibition by reducing the area power of the gamma frequency oscillations. In addition, parvalbumin expressing cells are significantly
altered in humans, specifically in areas associated with the development of prodromal stages of LBDs, these same areas correlated with regions that presented higher
Burden of αSyn phosphorylation. In conclusion, this thesis demonstrates that, reduction in density of parvalbumin cells depicts the impairments in gamma frequency
oscillations and correlates with an increase in αSyn PTMs in some regions of LBD patients
On the empirical economics of income persistence and class identity in the UK
Get PDFPhD ThesisSocioeconomic gradients in life outcomes are important political issues and a key area of
research for many applied economists. This thesis – comprising three empirical chapters –
represents the culmination of a process of research and investigation into the measurement of
income persistence and the role of class identity in shaping behaviour and health in the UK.
The first empirical chapter explores measures of intergenerational income persistence and their
sensitivity to researcher decisions. Using data from the British Cohort Study, 810 estimates of
intergenerational persistence are produced. The chapter is the first to estimate and report the
entire profile of persistence estimates with precedent in the literature for a given dataset.
Through a novel application of the techniques from meta-regression, the effects of each
researcher decision are estimated. The results confirm the existence of errors-in-variables and
lifecycle bias and show that seemingly innocuous changes to variable definitions can lead to
large fluctuations in persistence estimates. Rank coefficients are found to be the least sensitive
to researcher decisions and are thus preferred over elasticities or correlations for comparative
purposes.
The thesis progresses from measuring the intergenerational transmission of advantage, to the
process of how socioeconomic gradients occur. Specifically, from a health economics
perspective, how can we better understand differences in behaviours between socioeconomic
groups? The thesis applies a range of econometric methods to provide the first evidence on the
economic role of subjective class identity on smoking behaviour and the relationship between
relative deprivation and health.
The second empirical chapter focuses on subjective class identity and risky behaviour, as
measured by smoking. Data from the British Household Panel Survey (BHPS) suggests around
1 in 3 people in the UK state that they belong to a social class. A range of Two Part Models is
used to demonstrate behavioural differences between individuals with a class identity and those
without class identities. Working class identity individuals are more likely to smoke and, those
that do, consume more cigarettes than individuals with no class identity. These are the first
empirical findings to show that associations exist between subjective class identity and health
behaviours even after controlling for a host of socioeconomic characteristics. These findings
are consistent with predictions from the identity economics framework, given the literature on
class, smoking and stigma.
iii
The third empirical chapter again uses data from the BHPS, to examine whether class identity
has differential effects on the relationship between relative deprivation and measures of health
(self-assessed health and psychological well-being). Heterogeneity analyses allow the
associations to differ across subjective class identity groups. In measuring relative deprivation,
the reference groups - with which individuals compare themselves – are allowed to vary with
class identity. For each sample, outcome, and reference group, OLS is used alongside models
designed to control for unobservable heterogeneity. Once time constant unobserved differences
are controlled for there is no evidence of self-assessed health or psychological health costs from
relative deprivation for males. For females, there is a significant positive relationship between
relative deprivation and psychological well-being. This effect is driven by working class
women and hypothesised to be an aspiration effect, i.e. as incomes in the reference group
increase, the subject anticipates that their income too will increase, improving well-being.
Each empirical chapter focuses on an aspect of the central theme, socioeconomic gradients in
life outcomes. The key contributions are on the measurement of income persistence and the role
of subjective class identity on health behaviours and outcomes. The central implications are the
importance of transparency in the reporting of income persistence estimates and the need for
accurate comparisons. As well as the need to consider self-assessed class identity in studies of
risky behaviour and health inequalities, as these may provide more insight into the effects of
health interventions and the existence of hard-to-reach individuals. Throughout, results also
differ across gender, highlighting the need to consider gender when targeting policy messages
Expanding the scope of DNA compatible chemistry for the application within DNA encoded libraries
Get PDFPhD ThesisThe discovery of potential lead like molecules is a crucial phase for any drug discovery
program. Current methods to identify lead molecules are often resource intensive, often
requiring millions of compounds to be screened in biological assays. Reducing the time and
cost taken to generate, store and screen large compound libraries would have a positive
impact on academia and small pharmaceutical companies. DNA encoded libraries (DELs) aim
to improve upon this by screening an entire library in a single vessel against a target and
utilising the DNA tag to identify potential inhibitors. Current methods of preparing DELs are
limited to chemistry that is compatible with DNA. These chemical methods are often limited
to simple chemical reactions, such as cross-couplings and amide bond formation, which are
used combinatoriality to generate vast libraries. As analogous chemical reactions are used,
current libraries are often populated with compounds with similar physical properties and
have limited structural diversity. The reactions used to generate DELs are often low yielding,
or are limited in substrate scope, further reducing the diversity of potential libraries.
Development of new approaches with DEL synthesis will increase the ability to synthesise
libraries with greater chemical diversity and improved physical property profiles.
Products produced from the encoded transformation paradigm.
A new paradigm termed “encoded transformations” was introduced. This technique involves
encoding a specific chemical transformation of a reactive core molecule instead of coding the
addition of a building block. This would lead to a potential library of compounds with reduced
overall molecular weight and more lead-like physical properties. A common reactive 2-oxobetenamide core was used and several chemical transformations have been successfully
employed. These chemical transformations were developed off-DNA and provide a means to prepare libraries with significant scaffold diversity using DNA compatible chemistry.
Micellar solvents have been shown to improve normal phase organic chemical reactions.
Applying this technique to on-DNA synthesis vastly improved the scope and diversity of the
reactants used. Both amide couplings and Suzuki-Miyaura reactions were successfully
optimised utilising micellar media as a solvent. Optimisation was carried out in both examples
by factorial experimental design (FED), which revealed second order relationships between
variables tested that would not likely be discovered using conventional techniques.
Products produced from novel micellar promoted Suzuki-Miyaura and amide reactions.
These novel reactions were used to synthesise a prototype 6x6 library, which was PCR
amplified and sequenced proving that reactions in micellar media do not cause DNA damage.
The reverse amide coupling was then used to create a 99,405-member library, including
compounds designed to specifically target the SARs-CoV-2 main protease (Mpro) binding site,
using an array of both covalent and non-covalent inhibitors.AstraZenec
Real-Time QoS Monitoring and Anomaly Detection on Microservice-based Applications in Cloud-Edge Infrastructure
Get PDFPh. D. Thesis.Microservices have emerged as a new approach for developing and deploying cloud
applications that require higher levels of agility, scale, and reliability. A microservicebased
cloud application architecture advocates decomposition of monolithic application
components into independent software components called \microservices". As the
independent microservices can be developed, deployed, and updated independently of
each other, it leads to complex run-time performance monitoring and management
challenges. The deployment environment for microservices in multi-cloud environments
is very complex as there are numerous components running in heterogeneous
environments (VM/container) and communicating frequently with each other using
REST-based/REST-less APIs. In some cases, multiple components can also be executed
inside a VM/container making any failure or anomaly detection very complicated.
It is necessary to monitor the performance variation of all the service components
to detect any reason for failure.
Microservice and container architecture allows to design loose-coupled services and run
them in a lightweight runtime environment for more e cient scaling. Thus, containerbased
microservice deployment is now the standard model for hosting cloud applications
across industries. Despite the strongest scalability characteristic of this model
which opens the doors for further optimizations in both application structure and
performance, such characteristic adds an additional level of complexity to monitoring
application performance. Performance monitoring system can lead to severe application
outages if it is not able to successfully and quickly detecting failures and localizing
their causes. Machine learning-based techniques have been applied to detect anomalies
in microservice-based cloud-based applications. The existing research works used
di erent tracking algorithms to search the root cause if anomaly observed behaviour.
However, linking the observed failures of an application with their root causes by the
use of these techniques is still an open research problem.
Osmotic computing is a new IoT application programming paradigm that's driven
by the signi cant increase in resource capacity/capability at the network edge, along
with support for data transfer protocols that enable such resources to interact more
seamlessly with cloud-based services. Much of the di culty in Quality of Service (QoS)
and performance monitoring of IoT applications in an osmotic computing environment
is due to the massive scale and heterogeneity (IoT + edge + cloud) of computing
environments.
To handle monitoring and anomaly detection of microservices in cloud and edge datacenters,
this thesis presents multilateral research towards monitoring and anomaly
detection on microservice-based applications performance in cloud-edge infrastructure.
The key contributions of this thesis are as following:
• It introduces a novel system, Multi-microservices Multi-virtualization Multicloud
monitoring (M3 ) that provides a holistic approach to monitor the performance
of microservice-based application stacks deployed across multiple cloud
data centers.
• A framework forMonitoring, Anomaly Detection and Localization System (MADLS)
which utilizes a simpli ed approach that depends on commonly available metrics
o ering a simpli ed deployment environment for the developer.
• Developing a uni ed monitoring model for cloud-edge that provides an IoT application
administrator with detailed QoS information related to microservices
deployed across cloud and edge datacenters.Royal Embassy of Saudi Arabia Cultural
Bureau in London, government of Saudi Arabi
Understanding grit in an organisational context : the concept of grit and its role as a predictor of work-related stress and employee performance
Get PDFPhD ThesisIn recent years, non-cognitive personality factors have received increasing attention due to
studies that suggested that they could be highly important in employee selection and
development processes. Substantial research and practical reasoning suggests that the ability to
persevere and be passionate about one’s long-term goals despite challenges and setbacks is
considered a key factor of success in today’s society. This thesis focuses on grit, a non-cognitive
personality trait grit that has been defined as a combination of perseverance and passion for
long term goals.
Building on inconclusive preliminary results that indicated that grit might be a crucial
factor for employee performance and the experience of work-related stress, this thesis reports
on research that aimed to explore the applicability of grit in the workplace. The research used
a cross-sectional research design and empirically tested the predictive validity of grit on
individual performance and its relationship to PsyCap, resilience and work-related stress in a
stratified sample of the UK government’s Companies House Basic Company Data. To provide
a holistic insight into the impact of grit on job performance, the three dimensions of task
performance, organisational citizenship behaviour and innovative performance were assessed.
A survey method was applied to a cross sectional sample of 2089 employees to provide
generalisable results across UK workers.
The findings of this research suggest that despite issues in its current conceptualisation,
grit is a distinctive construct compared to resilience and PsyCap and impacts individual
outcomes in the organisational context. Furthermore, findings suggest that grit is a significant
predictor of job performance and work-related stress across the research sample. The findings
have significant implications for theory by showing that grit is a unique personality
characteristic that could enhance current HRM processes to increase employee performance
and reduce work-related stress
New Heteronormativity: The Gay-Straight Tipping Point in Suicide Prevention Amongst Male University Students in the U.S.
Get PDFEd. D. Thesis.In the United States, suicide is the second leading cause of death amongst university students
aged between 25 and 34, and the second leading cause of death overall for people aged
between 15 and 34. Men die by suicide at four times the rate of women across all age groups,
at roughly 20 deaths per 100,000 individuals. This has been the case since the 1950s and
stubbornly persists; defying interventions and harm reduction efforts designed to contain it.
While such figures and trends are reflected across much of the western world, the U.S. has a
particular problem. Young men at university are at the epicentre of the crisis. Prevention
efforts increasingly focus on identities and social lives, with research fractured along concepts
of sexuality, masculinity, and social constructs. This thesis examines this multifactorial, social
ecology, and adopts a phenomenological framework to understand the place of prevention in
the social and private spheres of male students at U.S. university campuses. The study
explored the lived experiences of 29 students and utilised interpretative phenomenological
analysis. The study found considerable understanding of constructed and socio-political
factors amongst the group, including how recent shifts in the U.S. government had
contributed to societal views of young men. Despite this self-insight, wavering resilience, and a
growing frustration with the failure of statutory systems and the government to intervene has
led to stalled prevention efforts in many university contexts. Academic and public health
models must, jointly, find new means to consider wider influencing arenas on suicidality,
heteronormativity, masculinity, sports, politics, and their place in the higher education
environment. Findings are of considerable importance to agencies related to, and working at
the forefront of, suicide prevention efforts and the intersection of masculinities and
suicidalities
Probing the evolutions and proliferations of beatmaking styles in hip hop music
Get PDFPh. D. Thesis.This PhD thesis investigates how a multiplicity of distinct styles of hip hop beats have materialised since hip hop music’s initial emergence from New York City in the 1970s.
From the outset, I assert that the beat, that is, the musical component that might be thought of as the ‘backing track’ of a hip hop record or live performance, should be considered just as fundamental as an MC’s vocals. I proceed to observe that while hip hop can be – and usually is – invoked to mean a single genre, examples of hip hop beats from disparate regions and periods can sound radically different from one another, exhibiting divergent sonic signatures and compositional approaches. My research seeks to discover and engage critically with the factors that have caused this stylistic diversity.
A musicological inquiry that eschews the priorities and standardisations of European-derived musical sensibilities in favour of a meaningful regard for hip hop culture’s aesthetics and creative strategies is pursued as I analyse a selection of significant region-specific and period-specific beat styles, and subsequently, a combination of online ethnographic work and a creative practice element leads my survey on the present state of underground beatmaking practice.
Drawing from theories and applications of dialectics, I find that the history of hip hop beats and beatmaking can be apprehended by scrutinising the relationship between underground musical movements and the agents of the capitalist culture industry, with these two conflicting sides effectively working in tandem to ensure hip hop’s continued position at the vanguard of modern popular music. Crucially, I suggest that hip hop beatmaking constitutes a truly revolutionary form of composition that exposes and explodes the latent potentials of music technologies, both established and novel.Northern Bridge AHRC Doctoral Training Partnershi
Real-time monitoring and forecasting of time series in healthcare applications
Get PDFPhd ThesisType II diabetes is an increasingly common disease, but one in which the effects suffered
by patients, such as hyperglycaemia, can be improved through careful monitoring and
control of the factors that influence blood glucose levels. Advances in the Internet of
Things (IoT) have made monitoring a person’s glucose levels more accessible, in that
a continuous glucose monitoring (CGM) device in the form of a small sensor can be
used to regularly report glucose levels to a bluetooth device, without the need for human
intervention. Modelling the data from CGM devices online allows for short-term forecasts
to be made that can assist in making real-time decisions regarding interventions to improve
future glucose levels, such as behavioural changes. Additional data to monitor how active
a person is can easily be collected by wrist-worn accelerometer devices. As activity levels
directly impact glucose levels, bivariate models between glucose and activity data aim to
provide improved forecasts.
State space models are fitted to glucose data and activity data using a Bayesian modelling framework. The posterior distributions of model parameters are learned via Markov
chain Monte Carlo (MCMC) methods. High frequency (100 Hz), tri-axial accelerometer
data are reported alongside glucose observations recorded at five minute intervals and
are transformed into univariate activity summaries. Discrete-valued state space models,
known as hidden Markov models (HMMs), are used to classify the observations from the
different activity summaries into activity intensities. Normal and skew Normal withinstate distributions are explored to better fit the observed activity summaries, as well as
fitting models to transformations of the summaries where possible to reduce the skewness
in the data.
Gaussian state space models, known as dynamic linear models (DLMs), are explored
to describe glucose levels, incorporating seasonal and autoregressive (AR) components.
The results from these models then provide the basis for bivariate models that incorporate
known activity states. This additional information is included in the DLMs as a regression
covariate, which is formed by a weighted sum of lagged activity zones. Models between
glucose levels and lagged carbohydrate intake are also considered, to better understand
the effects of activity and food on glucose levels.
A second application area is considered as an example of improved predictive performance where an influential variable is known alongside the quantity of interest. The
production levels of liquid natural gas (LNG) at a gas plant are modelled by a DLM, with
a regression on atmospheric temperature. The models are fitted in a frequentist framework
for simplicit
A Multimodal Critical Discourse Analysis of Entrepreneurship in Entre-tainment
Get PDFPhD ThesisOver the past decade entrepreneurship has featured heavily in spheres of entertainment such as
television. The term “entre-tainment” (Down, 2010) has been coined to capture the merging of,
entrepreneurship and entertainment (Swail et al, 2014). One form of “entre-tainment” that has
become widespread through international and globalised replication by approximately forty
different countries is the format of reality television programmes such as Dragons’ Den which
was the first version of the series in the English language. This thesis critically unpacks (i) the
discourses of entrepreneurship in popular culture surrounding this specific entre-tainment
genre, and (ii) what these discourses do, through Multimodal Critical Discourse Analysis. Three
datasets are analysed, which will be referred to as ‘Layers’. Layer 1 is the discourse within the
episodes of three versions of the television show, which are (i) Dragons’ Den (UK), (ii) Shark
Tank (USA) and (iii) Planting Seeds (Caribbean). Layer 2 surrounds media produced by the
show that is external to the episodes aired, and Layer 3 focuses on content produced by others
about the shows. Reviewing discourses across different Layers enhances the insight of the
interdiscursivity of entrepreneurship as constructed across social, cultural, and institutional
divides, as this research is not solely limited to the discourses confined within the television
shows but expands to include those from and about the shows. Entre-tainment was found to
legitimise a version of entrepreneurship that values wealth above all else. This was achieved by
positioning the desire and attainment of extreme individual wealth as morally and socially
acceptable, thus naturalising this ideology while obscuring alternative motivations and types of
entrepreneurship. Entre-tainment was also found to give celebrity entrepreneurs the power to
influence public opinion not only in areas of business, but also in areas of social life unrelated
to business enterprise, such as academia, government policy, marriage, parenting, and
managing personal finances. This work contributes to the area of critical entrepreneurship
studies as it fills the gap for research concerned with the influence cultural representations have
had on re-imagining the entrepreneur (e.g. Jones & Spicer, 2009)