3,051 research outputs found

    Postgraduate Instruction

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    "The object of this paper is to outline the postgraduate course in technical subjects and to show its value to the service. The time is opportune to present this subject, for nothing has been written for a number of years and in that time the course has progressed. The training of naval officers has received a great impetus since the war. A training division has been established in the Bureau of Navigation to have complete charge and direction of naval education and considerable has been written on the subject in the service papers and the newspapers.

    Transformative Urban Experimentation: Reimagining the Governance of Cities Towards Sustainability

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    This thesis by publication used action research to build capacity for grassroots agency and evaluate the direct impacts of urban experimentation from the perspective of participants in an urban living lab and investigated enabling processes of transformation through multiple case studies across a variety of socio-institutional contexts. This thesis developed an agency-centred analysis of urban experimentation to interpret how social learning, institutional arrangements, dynamics of transformation and capture and new urban imaginaries can drive the transformation of cities towards sustainability

    Functional Finite Mixture Modelling and Estimation

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    Functional data analysis is a branch of statistics that studies models for information represented by functions. Meanwhile, finite mixture models serve as a conerstone in the field of cluster analysis, offering a flexible probabilisitic framework for the representation of heterogeneous data. These models posit that the observed data are drawn from a mixture of several different probability distributions from the same family, where each is conventionally thought to represent a distinct group within the overall population. However, their representation in terms of densities makes their application to function-valued random variables, the foundation of functional data analysis, difficult. Herein, we utilize density surrogates derived from the Karhunen-Loeve expansion to circumvent this discrepancy and develop functional finite mixture models for the clustering of functional data. Models developed for real-valued and vector-valued functions of a single variable. Estimation of all models is done using the expectation-maximization algorithm, and copious amounts of simulations and data examples are provided to demonstrate the properties and performance of the methodologies. Additionally, we present a new estimation approach to be used in tandem with the stochastic expectation-maximization algorithm. This estimation method offers increased precision in estimation with respect to the algorithm chain length when compared to averaging the chain. Asymptotic properties of the estimator are derived, and simulation studies are given to demonstrate its performance

    Physical activity : strategies for school communities : based on strategies developed during the Be Active School & Community Project 1995-1998

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    The Be Active School and Community Project (BASC) operated in approximately 30 WA primary and secondary schools each year from August 1995 until December 1998 (three years). BASC was a Healthway funded project, promoting the National Heart Foundation\u27s Be Active Everyday message. Under the direction of a Management Committee, two project officers worked with the broad aim of increasing the physical activity rates of children at school and in the local community

    Leveraging 3D Atrial Geometry for the Evaluation of Atrial Fibrillation: A Comprehensive Review

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    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia associated with significant morbidity and mortality. Managing risk of stroke and AF burden are pillars of AF management. Atrial geometry has long been recognized as a useful measure in achieving these goals. However, traditional diagnostic approaches often overlook the complex spatial dynamics of the atria. This review explores the emerging role of three-dimensional (3D) atrial geometry in the evaluation and management of AF. Advancements in imaging technologies and computational modeling have enabled detailed reconstructions of atrial anatomy, providing insights into the pathophysiology of AF that were previously unattainable. We examine current methodologies for interpreting 3D atrial data, including qualitative, basic quantitative, global quantitative, and statistical shape modeling approaches. We discuss their integration into clinical practice, highlighting potential benefits such as personalized treatment strategies, improved outcome prediction, and informed treatment approaches. Additionally, we discuss the challenges and limitations associated with current approaches, including technical constraints and variable interpretations, and propose future directions for research and clinical applications. This comprehensive review underscores the transformative potential of leveraging 3D atrial geometry in the evaluation and management of AF, advocating for its broader adoption in clinical practice

    Small Molecule Inhibition of Gram-Positive Bacteria S. Aureus and C. Difficile

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    With the advent of antimicrobial molecules in the mid nineteenth century countless people were saved from life threatening infections. With decades of use, antimicrobials put enormous selective pressure on targeted pathogens resulting in resistances forming in many common microbes. These resistant strains of pathogens result in over two million illnesses, 23,000 deaths every year, and billions of dollars in medical expenses. This represents a need to research new molecules that have antimicrobial properties to combat the rise of resistance and prevent undue suffering to those afflicted. A small molecule is under investigation now that displays promising antimicrobial properties in preliminary studies against Candida species and many pathogenic gram-positive bacteria. The gram-positive bacteria that are inhibited by this small molecule at include Staphylococcus aureus, Streptococcus pneumonia, Listeria monocytogenes, Staphylococcus epidermidis, Streptococcus pyogenes, Bacillus cereus and Clostridium difficile. Research is currently focused on S. aureus and C. difficile with disk assays performed on both and plate assays performed on S. aureus to narrow down the minimum inhibitory concentration. C. difficile has a zone of inhibition of 9mm, while S. aureus has zone of inhibition at 10mm. The plate assay for S. aureus has shown a minimum inhibitory concentration to be between 150-100 uM of the small molecule, though further studies are needed. Plans are being made to find the mechanism of action of the small molecule by using mutant strains of S. aureus

    Is occupational physical activity associated with mortality in UK Biobank?

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    BackgroundCurrent physical activity guidelines do not distinguish between activity accumulated in different behavioural domains but some studies suggest that occupational physical activity (OPA) may not confer health benefits and could even be detrimental. The purpose of this study was to investigate associations between OPA and mortality outcomes.MethodsFrom baseline (2006-2010), 460,901 UK Biobank participants (aged 40-69 years) were followed for a median 12.0 (IQR: 11.3-12.7) years. OPA was categorised by cross-tabulating degree of manual work and walking/standing work amongst those in paid employment (n = 267,765), and combined with categories of occupational status for those not in paid employment (n = 193,136). Cox proportional hazards models were used to estimate sex-stratified hazard ratios (HR) and 95% confidence intervals (CI) for mortality from all causes, CVD, and cancer by occupational group, and for working hours/week and non-occupational physical activity stratified by occupational group. Models included adjustment for age and a range of lifestyle, socio-economic and health-related covariates.ResultsDuring 5,449,989 person-years of follow-up, 28,740 deaths occurred. Compared to those reporting no heavy manual or walking/standing work (e.g. sedentary office workers) and adjusting for covariates, retirement was associated with lower mortality in women (HR = 0.62, CI: 0.53-0.72) and men (HR = 0.80, CI: 0.71-0.90), whereas unemployment was associated with higher mortality in men only (HR = 1.24, CI: 1.07-1.45). Within the working population, there was no evidence of differences in all-cause, CVD or cancer mortality by OPA group when comparing those reporting higher levels of OPA to the lowest OPA reference group for both women and men. Working ConclusionsJobs classified as higher levels of OPA may not be as active as reported, or the types of physical activity performed in those jobs are not health-enhancing. Irrespective of OPA category or employment status, non-occupational physical activity appears to provide health benefits

    Genetic associations with childhood brain growth, defined in two longitudinal cohorts

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    Genome-wide association studies (GWASs) are unraveling the genetics of adult brain neuroanatomy as measured by cross-sectional anatomic magnetic resonance imaging (aMRI). However, the genetic mechanisms that shape childhood brain development are, as yet, largely unexplored. In this study we identify common genetic variants associated with childhood brain development as defined by longitudinal aMRI. Genome-wide single nucleotide polymorphism (SNP) data were determined in two cohorts: one enriched for attention-deficit/hyperactivity disorder (ADHD) (LONG cohort: 458 participants; 119 with ADHD) and the other from a population-based cohort (Generation R: 257 participants). The growth of the brain's major regions (cerebral cortex, white matter, basal ganglia, and cerebellum) and one region of interest (the right lateral prefrontal cortex) were defined on all individuals from two aMRIs, and a GWAS and a pathway analysis were performed. In addition, association between polygenic risk for ADHD and brain growth was determined for the LONG cohort. For white matter growth, GWAS meta-analysis identified a genome-wide significant intergenic SNP (rs12386571, P = 9.09 × 10-9 ), near AKR1B10. This gene is part of the aldo-keto reductase superfamily and shows neural expression. No enrichment of neural pathways was detected and polygenic risk for ADHD was not associated with the brain growth phenotypes in the LONG cohort that was enriched for the diagnosis of ADHD. The study illustrates the use of a novel brain growth phenotype defined in vivo for further study
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