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"O'Leary, Paul"
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Regularized Reconstruction of a Surface from its Measured Gradient Field
This paper presents several new algorithms for the regularized reconstruction of a surface from its measured gradient field. By taking a matrix-algebraic approach, we establish general framework for the regularized reconstruction problem based on the Sylvester Matrix Equation. Specifically, Spectral Regularization via Generalized Fourier Series (e.g., Discrete Cosine Functions, Gram Polynomials, Haar Functions, etc.), Tikhonov regularization, Constrained Regularization by imposing boundary conditions, and regularization via Weighted least squares can all be solved expediently in the context of the Sylvester Equation framework. State-of-the-art solutions to this problem are based on sparse matrix methods, which are no better than
O
n
6
algorithms for an
m
×
n
surface with
m
∼
n
. In contrast, the newly proposed methods are based on the global least squares cost function and are all
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3
algorithms. In fact, the new algorithms have the same computational complexity as an SVD of the same size. The new algorithms are several orders of magnitude faster than the state-of-the-art; we therefore present, for the first time, Monte-Carlo simulations demonstrating the statistical behaviour of the algorithms when subject to various forms of noise. We establish methods that yield the lower bound of their respective cost functions, and therefore represent the “Gold-Standard” benchmark solutions for the various forms of noise. The new methods are the first algorithms for regularized reconstruction on the order of megapixels, which is essential to methods such as Photometric Stereo.
Journal Article
Self‐Assembly of Linear, Natural Antimicrobial Peptides: An Evolutionary Perspective
Antimicrobial peptides are an ancient and innate system of host defence against a wide range of microbial assailants. Mechanistically, unstructured peptides undergo a secondary structure transition into amphipathic α‐helices, upon contact with membrane surfaces. This leads to peptide binding and removal of the membrane components in a detergent‐like manner or via self‐organisation into trans‐membrane pores (either barrel‐stave or toroidal pore) thereby destroying the microbe. Self‐assembly of antimicrobial peptides into oligomers and ultimately amyloid has been mostly examined in parallel, however recent findings link diseases, such as Alzheimer's disease as an aberrant activity of a protective neuropeptide with antimicrobial activity. These self‐assembled oligomers can also interact with membranes. Here, we review those antimicrobial peptides reported to self‐assemble into amyloid, where supported by structural evidence. We consider their membrane activities as antimicrobial peptides and present evidence of consistent self‐assembly patterns across major evolutionary groups. Trends are apparent across these groups, supporting the mounting data that self‐assembly of antimicrobial peptides into amyloid should be considered as synergistic to the antimicrobial peptide response. Antimicrobial peptides are an ancient defence against a wide range of microbes. Some can self‐assemble into oligomers and amyloid. Similarities with neurodegenerative diseases support a hypothesis that some diseases are due to aberrant activity of a protective neuropeptide. This review highlights the activities of antimicrobial peptides that can self‐assembly to form amyloid in major evolutionary groups.
Journal Article
Increased all-cause mortality following occupational injury: a comparison of two states
ObjectivesTo measure the impact of lost-time occupational injuries on all-cause mortality in Washington State and, using the same data elements and study design, to determine whether the estimated impact was similar to previous estimates for New Mexico.MethodsWe linked injuries in the Washington workers’ compensation system with Social Security Administration data on earnings and mortality. We estimated Cox survival models of mortality for women and men with lost-time compared with medical-only injuries, adjusting for age, pre-injury earnings and industry. We used quantitative bias analysis to account for confounding by pre-injury smoking and obesity.ResultsThe estimated mortality HR was 1.24 for women (95% CI 1.21 to 1.28) and 1.22 for men (95% CI 1.20 to 1.24). After adjusting for unmeasured pre-injury smoking and obesity, the estimated HR for women was 1.10, 95% simulation interval (SI) 1.00 to 1.21; for men, it was 1.15, 95% SI 1.04 to 1.27.ConclusionsAll-cause mortality for Washington workers with lost-time injuries was higher than for those with medical-only injuries. Estimated HRs for Washington were consistent with those previously estimated for New Mexico, a less populous state with lower median wages and a different workers’ compensation insurance mechanism. This suggests that the relationship between workplace injury and long-term mortality may be generalisable to other US states. These findings support greater efforts to enhance safety and to investigate factors that improve postinjury employment opportunities and long-term health. This association should be examined in additional locations, with different study conditions, or using additional data on pre-injury risk factors.
Journal Article
Opioid-related mortality after occupational injury in Washington State: accounting for preinjury opioid use
ObjectivesTo estimate the impact of occupational injury and illness on opioid-related mortality while accounting for confounding by preinjury opioid use.MethodsWe employed a retrospective cohort study design using Washington State workers’ compensation data for 1994–2000 injuries linked to US Social Security Administration earnings and mortality data and National Death Index (NDI) cause of death data from 1994 to 2018. We categorised injuries as lost-time versus medical-only, where the former involved more than 3 days off work or permanent disability. We determined death status and cause of death from NDI records. We modelled separate Fine and Gray subdistribution hazard ratios (sHRs) and 95% CIs for injured men and women for opioid-related and all drug-related mortality through 2018. We used quantitative bias analysis to account for unmeasured confounding by preinjury opioid use.ResultsThe hazard of opioid-related mortality was elevated for workers with lost-time relative to medical-only injuries: sHR for men: 1.53, 95% CI 1.41 to 1.66; for women: 1.31, 95% CI 1.16 to 1.48. Accounting for preinjury opioid use, effect sizes were reduced but remained elevated: sHR for men was 1.43, 95% simulation interval (SI) 1.20 to 1.69; for women: 1.27, 95% SI 1.10 to 1.45.ConclusionsOccupational injuries and illnesses severe enough to require more than 3 days off work are associated with an increase in the hazard of opioid-related mortality. The estimated increase is reduced when we account for preinjury opioid use, but it remains substantial. Reducing work-related injuries and postinjury opioid prescribing and improving employment and income security may decrease opioid-related mortality.
Journal Article
Quality Framework Performance in One Year of COVID-19 Restrictions in a Higher Education Institute
The entire academic year 2020-21 was completed under COVID-19 restrictions. This created challenges for students and staff, and to the quality frameworks that underpin the higher education (HE) being offered. Higher education (HE) quality frameworks were tested in a manner that had not been foreseen on their creation. This work examines the performance of one HE framework, which was created long before national lockdowns or social distancing, after an entire academic year of2020-21. Critical evaluation will be offered by the authors, by external examiners, from student surveys and from an institutional quality review panel which took place in the academic year. The aim is to evaluate if the quality framework was sufficiently robust to offer our students a quality education experience, to evaluate the impact of some operational modifications and to reassure the public in terms of the standard of our graduates.
Journal Article
EFFECTS OF THE TICKET TO WORK PROGRAM: RETURN ON INVESTMENT AND OVERALL ASSESSMENT OF OUTCOMES VERSUS DESIGN
The Ticket to Work (TTW) program was established by 1999 legislation to expand access to vocational rehabilitation services for beneficiaries of Social Security Administration (SSA) disability benefit programs. We evaluate TTW and compare its outcomes with the intentions of its authorizing legislation. We also compare the program 's costs with the benefit savings resulting from the reemployment of successful program participants. We analyze unadjusted descriptive statistics, then consider potential participation bias among individuals who received employment services by devising an econometric analysis that accounts for the seriousness of a participant's interest in work. We find that TTW improved employment outcomes and generated net benefit savings to SSA for many employment-service clients, but the savings did not fully offset program costs. However, these estimates should be regarded as lower bounds of TTW's positive effects because they do not account for higher service needs of TTW program participants.
Journal Article
Visual Inspection of Machined Metallic High-Precision Surfaces
This paper presents a surface inspection prototype of an automatic system for precision ground metallic surfaces, in this case bearing rolls. The surface reflectance properties are modeled and verified with optical experiments. The aim being to determine the optical arrangement for illumination and observation, where the contrast between errors and intact surface is maximized. A new adaptive threshold selection algorithm for segmentation is presented. Additionally, is included an evaluation of a large number of published sequential search algorithms for selection of the best subset of features for the classification with a comparison of their computational requirements. Finally, the results of classification for 540 flaw images are presented.
Journal Article
A tolerant nation?
Wales is a changing nation, it incorporates peoples of different inheritances, backgrounds and perspectives, all of whom will contribute to shaping the nation's future. A Tolerant Nation? presents the first overview of the past two hundred years of ethnic diversity in Wales and demonstrates the significance of this diversity for understanding contemporary Wales. In addition to providing a historical context for understanding Welsh multiculturalism, the essays collected here also discuss dominant views of ethnic diversity in Wales and the ways in which the Welsh themselves have been conceived of as an ethnic minority, both within and outside Wales. Individual essays reflect on issues such as the literary representation of race, Welsh missionary activities, racial tensions, refugees and asylum seekers in Wales, and the question of equality. A Tolerant Nation? illustrates the significant contribution of ethnic minorities in Wales to the development of Welsh economic, social and cultural life. It offers a revealing insight into the rich diversity of contemporary Wales, and fills a glaring gap in current research on the state of the devolved nation.
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