3,775 research outputs found
Understanding Cognitive Variability in Alzheimer’s Disease
Alzheimer’s Disease (AD) is highly heterogenous, both clinically and biologically. This variability is exacerbated by the ways within which, the clinical presentation is assessed with cognitive measures. This inhibits clinical trial success and earlier diagnosis of individuals. Marrying the clinical presentation to the pathology of the disease has so far proved troublesome. This thesis will look at how cognitive measures can best capture the clinical presentation of AD and how these measures can link to the underlying pathology using machine learning methods.
This thesis studied this problem across four analyses and two cohorts. Each study looked at a different aspect of cognitive testing within AD. This was done with the overarching aim to interrogate the cognitive variability across the spectrum of AD.
Study 1 showed a novel discrepancy score is different to memory measures at screening for AD. It also showed it tracks with AD severity, in the same way memory recall does. Studies 2 & 3 uncovered broad psychometric variance within amnestic measurement of impairment due to AD. This was done in two different populations across two different constructs of amnestic measurement, story recall and verbal list learning. These tests are frequently used interchangeably. These two studies show they should not be. Finally, Study 4 built models from cognitive measures to predict AD pathology. The performance of these models was moderate showing that even with novel cognitive measures, further work is needed to link the clinical and amyloid related biological presentations of AD.
Bridging the gap between clinical presentation and pathology of AD using clinical and cognitive markers alone is not possible. Even when using a novel measure of discrepancy score. The discrepancy measure shows promise but was limited due to the inability of the MMSE to measure verbal ability. Conceptually a discrepancy score remains a promising avenue of research for screening, but broader language measures, as well as other AD biomarkers are needed to further test the construct validity of this measure
Pushing Purcell-enhancement beyond its limits
Purcell-enhanced emission from a coupled emitter-cavity system is a
fundamental manifestation of cavity quantum electrodynamics. Starting from a
theoretical description we derive a scheme for photon emission from an emitter
coupled to a birefringent cavity that exceeds hitherto anticipated limitations.
Based on a recent study and experimental investigation of the intra-cavity
coupling of orthogonal polarisation modes in birefringent cavities, we now
decouple the emitter and the photon prior to emission from the cavity mode.
Effectively, this is "hiding" the emitter from the photon in the cavity to
suppress re-excitation, increasing the overall emission through the cavity
mirrors. In doing so we show that tailored cavity birefringence can offer
significant advantages and that these are practically achievable within the
bounds of present-day technology. It is found that birefringence can mitigate
the tradeoff between stronger emitter-cavity coupling and efficient photon
extraction. This allows for longer cavities to be constructed without a loss of
performance -- a significant result for applications where dielectric mirrors
interfere with any trapping fields confining the emitter. We then generalise
our model to consider a variety of equivalent schemes. For instance, detuning a
pair of ground states in a three-level emitter coupled to a cavity in a
Lambda-system is shown to provide the same enhancement, and it can be combined
with a birefringent cavity to further increase performance. Additionally, it is
found that when directly connecting multiple ground states of the emitter to
form a chain of coupled states, the extraction efficiency approaches its
fundamental upper limit. The principles proposed in this work can be applied in
multiple ways to any emitter-cavity system, paving the way to surpassing the
traditional limits of such systems with technologies that exist today.Comment: 8 pages, 8 figures plus 3 page appendi
Taking the C out of CVMFS
The Cern Virtual Machine File System is most well known as a distribution mechanism for the WLCG VOs@@ experiment software; as a result, almost all the existing expertise is in installing clients mount the central Cern repositories. We report the results of an initial experiment in using the cvmfs server packages to provide Glasgow-based repository aimed at software provisioning for small UK-local VOs. In general, although the documentation is sparse, server configuration is reasonably easy, with some experimentation. We discuss the advantages of local CVMFS repositories for sites, with some examples from our test VOs, vo.optics.ac.uk and neiss.org.uk
A NeISS collaboration to develop and use e-infrastructure for large-scale social simulation
The National e-Infrastructure for Social Simulation (NeISS) project is focused on
developing e-Infrastructure to support social simulation research. Part of NeISS aims to
provide an interface for running contemporary dynamic demographic social simulation
models as developed in the GENESIS project. These GENESIS models operate at the
individual person level and are stochastic. This paper focuses on support for a simplistic
demographic change model that has a daily time steps, and is typically run for a number
of years.
A portal based Graphical User Interface (GUI) has been developed as a set
of standard portlets. One portlet is for specifying model parameters and setting a
simulation running. Another is for comparing the results of different simulation runs.
Other portlets are for monitoring submitted jobs and for interfacing with an archive of
results. A layer of programs enacted by the portlets stage data in and submit jobs to a
Grid computer which then runs a specific GENESIS model program executable. Once a
job is submitted, some details are communicated back to a job monitoring portlet. Once
the job is completed, results are stored and made available for download and further
processing. Collectively we call the system the Genesis Simulator.
Progress in the development of the Genesis Simulator was presented at the UK e-
Science All Hands Meeting in September 2011 by way of a video based demonstration
of the GUI, and an oral presentation of a working paper. Since then, an automated
framework has been developed to run simulations for a number of years in yearly time
steps. The demographic models have also been improved in a number of ways. This
paper summarises the work to date, presents some of the latest results and considers the
next steps we are planning in this work
The Incompatibility of Certain Alcohol and Soap Frothers
The purpose of this thesis is to elucidate this phenomena of frother incompatibility, and to offer an explanation based upon several divergent lines of investigation. The research was limited to four common frothing agents, namely, pine oil, n-amyl alcohol, sodium oleate, and sodium lauryl sulphate (Dreft)
A Study of a Systematic Evangelistic Discipleship Process at the Lighthouse Free Methodist Church
The Lighthouse Free Methodist Church in Barryton, Michigan, lacks a systematic discipleship program that produces disciple-makers. This Doctor of Ministry project purposes to integrate a systematic discipleship program into the Lighthouse Free Methodist Church. The research methodology includes pre-and post-surveys and interviews. Pre- and post-survey data were collected to compare the number of disciplers, salvations, worship attenders, and the number of new systematic evangelistic discipleship groups. Six People participated in the training provided. The Lighthouse FMC is located near a small community of three-hundred people and is in the middle of a ten-mile circumference with thirty thousand. Thirteen people started to attend Worship services during and just after the completion of the project. One adult salvation was reported, which matched all the adult salvations reported in both 2017 and 2019. The six participants made eight new contacts and began to disciple six other people during the eight-week project. The project participants learned how to engage people in spiritual conversations, pray at the moment people present a need, lead an inductive Bible study, set goals, work lead behaviors, lead people in a prayer of salvation, and engage in systematic evangelistic discipleship
A model for ultrasonic transducers in a high-temperature regime with boundary dynamics : an evolutionary equations approach
In this thesis we formulate an abstract model to describe ultrasonic transducers, taking into account a high-temperature regime as well as dynamics at the boundary. We use an abstract boundary trace theory to extend from a known thermo-piezo-electromagnetic system, and encode boundary dynamics directly within our model. Using the theory of evolutionary equations invented by Rainer Picard, we establish the well-posedness of our system. Well-posedness in this context corresponds to both Hadamard well-posedness and causal dependence on given data. Moreover, we conduct a systematic
investigation into different arrangements of complicated boundary dynamics which lead to a well-posed system. Motivated by a set of known piezo-electric boundary conditions, we formulate and consider novel generalised impedance like boundary conditions. Furthermore, we formulate and analyse a specific example of these generalised boundary dynamics, which account also for the influence of heat at the boundary. The resulting example pertains to all three physical aspects of our system, and thus harnesses the full generality afforded by our system.In this thesis we formulate an abstract model to describe ultrasonic transducers, taking into account a high-temperature regime as well as dynamics at the boundary. We use an abstract boundary trace theory to extend from a known thermo-piezo-electromagnetic system, and encode boundary dynamics directly within our model. Using the theory of evolutionary equations invented by Rainer Picard, we establish the well-posedness of our system. Well-posedness in this context corresponds to both Hadamard well-posedness and causal dependence on given data. Moreover, we conduct a systematic
investigation into different arrangements of complicated boundary dynamics which lead to a well-posed system. Motivated by a set of known piezo-electric boundary conditions, we formulate and consider novel generalised impedance like boundary conditions. Furthermore, we formulate and analyse a specific example of these generalised boundary dynamics, which account also for the influence of heat at the boundary. The resulting example pertains to all three physical aspects of our system, and thus harnesses the full generality afforded by our system
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