Diffeomorphic Demons using Normalised Mutual Information, Evaluation on Multi-Modal Brain MR Images

The demons algorithm is a fast non-parametric non-rigid registration method. In recent years great efforts have been made to improve the approach; the state of the art version yields symmetric inverse-consistent large-deformation diffeomorphisms. However, only limited work has explored inter-modal similarity metrics, with no practical evaluation on multi-modality data. We present a diffeomorphic demons implementation using the analytical gradient of Normalised Mutual Information (NMI) in a conjugate gradient optimiser. We report the first qualitative and quantitative assessment of the demons for inter-modal registration. Experiments to spatially normalise real MR images, and to recover simulated deformation fields, demonstrate (i) similar accuracy from NMI-demons and classical demons when the latter may be used, and (ii) similar accuracy for NMI-demons on T1w-T1w and T1w-T2w registration, demonstrating its potential in multi-modal scenarios

Advances in neuroimaging in frontotemporal dementia

Frontotemporal dementia (FTD) is a clinically and neuroanatomically heterogeneous neurodegenerative disorder with multiple underlying genetic and pathological causes. Whilst initial neuroimaging studies highlighted the presence of frontal and temporal lobe atrophy or hypometabolism as the unifying feature in patients with FTD, more detailed studies have revealed diverse patterns across individuals, with variable frontal or temporal predominance, differing degrees of asymmetry, and the involvement of other cortical areas including the insula and cingulate, as well as subcortical structures such as the basal ganglia and thalamus. Recent advances in novel imaging modalities including diffusion tensor imaging, resting-state functional magnetic resonance imaging and molecular positron emission tomography imaging allow the possibility of investigating alterations in structural and functional connectivity and the visualisation of pathological protein deposition. This review will cover the major imaging modalities currently used in research and clinical practice, focusing on the key insights they have provided into FTD, including the onset and evolution of pathological changes and also importantly their utility as biomarkers for disease detection and staging, differential diagnosis and measurement of disease progression. Validating neuroimaging biomarkers that are able to accomplish these tasks will be crucial for the ultimate goal of powering upcoming clinical trials by correctly stratifying patient enrolment and providing sensitive markers for evaluating the effects and efficacy of disease-modifying therapies

Accuracy assessment of global and local atrophy measurement techniques with realistic simulated longitudinal data

The main goal of this work was to assess the accuracy of several well-known methods which provide global (BSI and SIENA) or local (Jacobian integration) estimates of longitudinal atrophy in brain structures using Magnetic Resonance images. For that purpose, we have generated realistic simulated images which mimic the patterns of change obtained from a cohort of 19 real controls and 27 probable Alzheimer's disease patients. SIENA and BSI results correlate very well with gold standard data (BSI mean absolute error < 0.29%; SIENA < 0.44%). Jacobian integration was guided by both fluid and FFD-based registration techniques and resulting deformation fields and associated Jacobians were compared, region by region, with gold standard ones. The FFD registration technique provided more satisfactory results than the fluid one. Mean absolute error differences between volume changes given by the FFD-based technique and the gold standard were: sulcal CSF < 2.49%; lateral ventricles < 2.25%; brain < 0.36%; hippocampi < 1.42%

African American freshman students at UNC Asheville: a strategy for retention and success

Enrollment of African American students at predominantly white institutions has seen substantial growth since the late 1970s due in great part to federal legislation such as affirmative action and other access-focused policies. Broad specified judicial actions like these should have eased the path for public universities to welcome and retain African American students in large numbers (Bobo, 1998). However, multiple issues continue to exist that thwart university access and success, and African Americans continue to drop out at high rates, especially in their freshman year (Townsend, 2007). These problems include complex university cultures, continued lack of access, poor academic preparation, low sense of belonging, and challenging social and academic climates. Research demonstrates that African American students, once admitted to college, continue to believe they do not belong in these educational settings (Harper &amp; Griffin, 2011). We must improve the retention and success of these students by providing programs and resources that facilitate their social and academic transition into the collegiate environment. In this disquisition, I address the impact of a residential living learning community specifically for African American students, called SANKOFA. The hope is that having a group of students with similar cultural backgrounds in addition to providing specific training of faculty and staff to facilitate coursework and educational programming for this population, the sense of belonging to UNC Asheville will increase for these students. Once integrated, their opportunities for success in that first year of college can improve, which enhances their chances of graduation by almost 40% (Smedley, B.D., 2000)

The Progression of Women in Legislation: From Property to People

In this thesis, the transformation of the legal status of women will be examined. Beginning with a discussion of the common law foundations and focusing especially on coverture, this paper will provide a history of how women’s place in society developed through legislation as they gradually evolved from being recognized as the property of their husbands to being sovereign individuals. This progression for women was slow, and remains incomplete. Despite progress, echoes of patriarchal oppression still exist in law today

Evaluation of torso stability using the basin of stability chair

Low back pain (LBP) is a costly problem in modern health care that affects up to 80% of the population at some point in life. The link between low back and torso instability or spinal motion has not been clearly defined. Past studies evaluating torso dynamics have employed the use of unstable seating apparatuses to analyze various aspects of human torso stability. Traditionally, these devices measure Kinematic Variability (KV). However, previous devices had design limitations making them unable to measure dynamic stability parameters such as the Basin of Stability (BoS). In this research project an innovative new device for measuring unstable seating was designed, constructed, and performance tested. The new device, the BoS Chair, presented several key challenges and required the custom fabrication of each major component utilizing CAD software and CNC machinery. A new seating arrangement was devised using a kneeling chair configuration to isolate the upper torso. The new seating configuration implemented a high deflection angle joint allowing the chair to tilt farther than previous devices enabling the calculation of the basin of stability. The design also required the ability to adjust restorative torque, known simply as the difficulty level. These features required safety measures and a sturdy safety frame to accompany the device. Testing of the new BoS chair required the formulation of Threshold of Stability (ToS) and Basin of Stability test procedures. The ToS procedure tested participants through a series of increasing difficulties until failure was detected. The point of failure marked the threshold of the participant. Using the ToS information, a preliminary BoS procedure was conducted to record temporal movement parameters using a gyroscopic sensor. Tests were conducted with six male and six female participants. ToS trials were statistically compared and analyzed, revealing that height and weight had a significant confounding effect on the results. The effect was successfully remedied through normalization. It showed that the BoS chair could be used to study the torso balance control of participants regardless of their size. The stability graphs and stabilograms generated from the preliminary BoS data indicated that the recording device and trial methods were sufficient. These initial Basin of Stability tests will form the foundation for the development of future BoS testing protocols. The BoS chair is as a durable and flexible tool for measuring torso stability that was designed to detect Lagrangian Coherent structures in a novel way. The preliminary BoS data collected in this research will be useful for future Basin of Stability research and provide preliminary data for grant proposals. With the device constructed and baseline data available for human subjects (i.e. controls), we are now prepared for future projects that measure torso stability in patient populations to improve our understanding of this condition and its effect on low back pain

Restoration

My thesis essay and creative work examines and critiques contemporary attitudes towards environmental sustainability by exploring the philosophies and practices of earlier global cultures that led them to a more harmonious existence with the natural world. My interest in this subject is intensely personal and based on my experience as an immigrant to the U.S. Growing up in the mountains of Colombia, I learned the importance of balance in life. We understood that our actions had a direct effect on the environment. As children, we are taught that humans are deeply connected to nature, dependent on its vital resources for survival and, therefore, responsible for acting as caretakers of our environment for the benefit of our entire community. In moving to the U.S., I observed many differences including a disconnection between people and nature, which is most evident in the vast amount of consumption and misuse of resources. As a citizen, I am concerned about what is lost when we remove the natural world from our lives and value a sanitized way of life that is mainly concerned with convenience. My research investigates cultures that for centuries, have lived in harmony and balance with the natural world. My research intended to compel the viewer to think about what these cultures might teach us about the way we distribute and use natural resources. My hope is to make work that contributes to a deeper appreciation and awareness of the consequence of our culture

Sign segmentation with changepoint-modulated pseudo-labelling

The objective of this work is to find temporal boundaries between signs in continuous sign language. Motivated by the paucity of annotation available for this task, we propose a simple yet effective algorithm to improve segmentation performance on unlabelled signing footage from a domain of interest. We make the following contributions: (1) We motivate and introduce the task of source-free domain adaptation for sign language segmentation, in which labelled source data is available for an initial training phase, but is not available during adaptation. (2) We propose the Changepoint-Modulated Pseudo-Labelling (CMPL) algorithm to leverage cues from abrupt changes in motion-sensitive feature space to improve pseudo-labelling quality for adaptation. (3) We showcase the effectiveness of our approach for category-agnostic sign segmentation, transferring from the BSLCORPUS to the BSL-1K and RWTH-PHOENIX-Weather 2014 datasets, where we outperform the prior state of the art