922017 research outputs found
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On Local Input-Output Stability of Nonlinear Feedback Systems via Local Graph Separation
No full textA new type of local input-output stability for nonlinear systems is defined, called M-local boundedness, which can be viewed as a local version of established definitions of global boundedness. This definition states that the system is bounded if the input Lebesgue signal has a norm smaller than M. Using graph separation concepts and a novel topological argument, which partitions the output space of the system into feasible and infeasible regions based on the restriction of the system input, sufficient conditions for M-local boundedness of a nonlinear feedback system are derived. Using this theorem, a new local nonlinear small gain condition is found for a closed-loop system with additive inputs. This small gain condition is then used in a numerical example, in which a differential equation with a quadratic element was partitioned into a feedback system and bounds on the norm of the input were found which ensured the system was M-locally stable
Applications of Immersive Technologies for Occupational Safety and Health Management in the Construction Industry: A Systematic Review
No full textThe construction industry contributes significantly to workplace fatalities and injuries despite multiple interventions implemented by governments and construction companies. Recently, immersive technologies as part of a suite of industry 4.0 technologies have also strongly emerged as a viable pathway to help address poor construction occupational safety and health (OSH) performance. A review of literature on the application of immersive technologies for construction OSH management is conducted with the aim of gaining a broader view of different construction OSH areas using the preferred reporting items for systematic reviews and meta-analysis (PRISMA) approach. The evaluation of 79 relevant articles were carried out, selected from Scopus database. The review revealed that literature have focused on the application of various immersive technologies for hazard identification and visualisation, safety training, design for safety, risk perception and assessment in various construction works. This review identified several limitations regarding the use of immersive technologies, which include the low level of adoption of developed immersive technologies for OSH management, very limited research works on the application of immersive technologies for health hazards and limited focus on the effectiveness of various immersive technologies for construction OSH management. Future research should identify possible reasons for the low level knowledge transfer from research to practice and proffer ways of addressing the identified reasons. The effectiveness of the use of immersive technologies for addressing health hazards should also be investigated
Bridging disconnected networks of first and second lines of biologic therapies in rheumatoid arthritis with registry data: Bayesian evidence synthesis with target trial emulation
No full textObjective: We aim to utilise real world data in evidence synthesis to optimise an evidence base for the effectiveness of biologic therapies in rheumatoid arthritis in order to allow for evidence on first-line therapies to inform second-line effectiveness estimates.Study design and setting: We use data from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis (BSRBR-RA) to supplement RCT evidence obtained from the literature, by emulating target trials of treatment sequences to estimate treatment effects in each line of therapy. Treatment effects estimates from the target trials inform a bivariate network meta-analysis (NMA) of first and second-line treatments.Results: Summary data were obtained from 21 trials of biologic therapies including 2 for second-line treatment and results from six emulated target trials of both treatment lines. Bivariate NMA resulted in a decrease in uncertainty around the effectiveness estimates of the second-line therapies, when compared to the results of univariate NMA, and allowed for predictions of treatment effects not evaluated in second-line RCTs.Conclusion: Bivariate NMA provides effectiveness estimates for all treatments in first- and second-line, including predicted effects in second-line where these estimates did not exist in the data. This novel methodology may have further applications, for example for bridging networks of trials in children and adults
Clinical outcome and underlying genetic cause of functional terminal complement pathway deficiencies in a multi-center UK cohort
No full textBackground: Terminal complement pathway deficiencies often present with severe and recurrent infections. There is a lack of good quality data on these rare conditions. This study investigated the clinical outcome and genetic variation in a large UK multi-center cohort with primary and secondary terminal complement deficiencies. Methods: Clinicians from seven UK centers provided anonymised demographic, clinical and laboratory data on patients with terminal complement deficiencies, which were collated and analysed. Results: Forty patients, median age 19 (range 3 62) years, were identified with terminal complement deficiencies. Ten (62%) of 16 patients with low serum C5 concentrations had underlying pathogenic CFH or CFI gene variants. Two-thirds were from consanguineous Asian families and 80% had an affected family member. The median age of first infection was nine years. Forty-three percent suffered meningococcal serotype B, and 43% serotype Y infections. Nine (22%) were treated in intensive care for meningococcal septicemia. Two patients had died, one from intercurrent COVID-19. Twenty-one (52%) were asymptomatic and diagnosed based on family history. All but one patient had received booster meningococcal vaccines and 70% were taking prophylactic antibiotics. Discussion: The genetic etiology and clinical course of patients with primary and secondary terminal complement deficiency is variable. Patients with low antigenic C5 concentrations require genetic testing, as the low level may reflect consumption secondary to regulatory defects in the pathway. Screening of siblings is important. Only half of patients develop septicemia, but all should have a clear management plan. Key words: terminal complement pathway; Factor H; Factor I; meningococcal infection; genetic
‘Enter Parliament but never become part of it’: How have the Greens in the UK Approached Opposition?
No full textThe Greens in the UK have benefited from the fragmentation of the party system and the creation of devolved institutions, achieving consistent representation at multiple levels of British politics in recent years. However, we know little about what they have done in these positions. This study uses interviews with Green legislators to investigate how they have interpreted the task of opposition at Westminster, Holyrood and Stormont. We show that Green legislators’ approaches to opposition have been influenced by their party identity, and that differences in approach between the institutions have largely been determined by contrasting political opportunity structures, rather than parliamentary rules. These findings highlight the importance of party as a factor shaping opposition strategy and the varied roles which opposition parties can play within the UK political system
FuSeBMC v4: Smart Seed Generation for Hybrid Fuzzing
No full textFuSeBMC is a test generator for finding security vulnerabilities in C programs. In Test-Comp 2021, we described a previous version that incrementally injected labels to guide Bounded Model Checking (BMC) and Evolutionary Fuzzing engines to produce test cases for code coverage and bug finding. This paper introduces an improved version of FuSeBMC that utilizes both engines to produce smart seeds. First, the engines run with a short time limit on a lightly instrumented version of the program to produce the seeds. The BMC engine is particularly useful in producing seeds that can pass through complex mathematical guards. Then, FuSeBMC runs its engines with extended time limits using the smart seeds created in the previous round. FuSeBMC manages this process in two main ways. Firstly, it uses shared memory to record the labels covered by each test case. Secondly, it evaluates test cases, and those of high impact are turned into seeds for subsequent test fuzzing. In this year’s competition, we participate in the Cover-Error, Cover-Branches, and Overall categories. The Test-Comp 2022 results show that we significantly increased our code coverage score from last year, outperforming all tools in all categories.<br/
Predictors of myocardial fibrosis and response to anti-fibrotic therapy in heart failure with preserved ejection fraction
No full textPurpose: Myocardial fibrosis, measured using magnetic resonance extracellular volume (ECV), associates with adverse outcome in heart failure with preserved ejection fraction (HFpEF). In the PIROUETTE (The Pirfenidone in Patients with Heart Failure and Preserved Left Ventricular Ejection Fraction) trial, the novel anti-fibrotic agent pirfenidone reduced myocardial fibrosis. We sought to identify baseline characteristics that associate with myocardial fibrotic burden, the change in myocardial fibrosis over a year, and predict response to pirfenidone in patients with HFpEF. Methods: Amongst patients enrolled in the PIROUETTE trial (n=107), linear regression models were used to assess the relationship between baseline variables and baseline myocardial ECV, with change in myocardial ECV adjusting for treatment allocation, and to identify variables that modified the pirfenidone treatment effect.Results: Body mass index, left atrial reservoir strain, haemoglobin and aortic distensibility were associated with baseline ECV in stepwise modelling, and systolic blood pressure, and log N-terminal pro B-type natriuretic peptide were associated with baseline ECV in clinically-guided modelling. QRS duration, left ventricular mass and presence of an infarct at baseline were associated with an increase in ECV from baseline to week 52. Whilst QRS duration, presence of an infarct, global longitudinal strain and left atrial strain modified the treatment effect of pirfenidone when considered individually, no variable modified treatment effect on multivariable modelling.Conclusion: Baseline characteristics were identified that associate with myocardial fibrosis and predict change in myocardial fibrosis. No variables that independently modify the treatment effect of pirfenidone were identified (PIROUETTE, NCT02932566). Keywords: Heart failure, myocardial fibrosis, magnetic resonance imaging (MRI), extracellular volume (ECV)<br/
Advancing Australian Public Health Initiatives Targeting Dementia Risk Reduction
No full textPublic health initiatives aim to improve health outcomes for populations by preventing disease and the health consequences of environmental hazards and natural or human-made disasters. Whilst public health initiatives have been successfully used to modify behaviours for chronic diseases yet many initiatives targeting reduced dementia risk in older adults suffer from conceptual and statistical flaws that greatly limit their usefulness. The limited success in modifying lifestyle dementia risk factors has led us to fall short in building a successful roadmap to dementia risk reduction. Here we argue for adopting a population-level, holistic approach to dementia risk reduction strategies across the lifespan. This approach is supplemented by 10 strategies that focus on improving social policies, harnessing existing policy, legislature and incentive schemes, and identifying feasible approaches to increase recreational and transport-related physical activity to creating best practice healthcare that supports healthy brain ageing for all.Key words: Health policy, health services, public health, gerontology, dementi
Effect of low pressure plasma surface modification on filtration performance of chitosan nanofibrous respiratory filter
No full textLow pressure drop is highly desirable for respiratory filters. Surface activation plays an important role to enhance the filtration performance of respiratory filters. In this study, a three-layer composite respiratory filter was developed using a combination of polypropylene (PP) nonwoven layers and chitosan nanofibres (CSNF) with variable coating time (h) during the electrospinning process. To study the impact of surface activation on filtration performance, the outer surface of all the samples were modified using low-pressure plasma treatment. Filtration performance testing was conducted to determine the filtration efficiency (%), pressure drop (Pa), and quality factor (Q) results, before and after the surface treatment. The maximum values of filtration efficiency and quality factor achieved were 99.99% and 0.068, respectively. The lowest value of the pressure drop was 16.12 Pa. All the low-pressure plasma-treated samples showed higher filtration efficiency and quality factor compared to untreated samples due to a more effective capturing mechanism. However, pressure drop results indicated no significant difference. Furthermore, the decay of plasma treatment impact was analysed by using drop shape analysis method to measure the water contact angle on the surface of the samples. Results showed a gradual decrease in surface modification impact and the surface of the treated samples changed from hydrophilic to hydrophobic with the passage of time.</p
An asymptotic approach to proving sufficiency of Stein characterisations
No full textIn extending Stein's method to new target distributions, the first step is to find a Stein operator that suitably characterises the target distribution. In this paper, we introduce a widely applicable technique for proving sufficiency of these Stein characterisations, which can be applied when the Stein operators are linear differential operators with polynomial coefficients. The approach involves performing an asymptotic analysis to prove that only one characteristic function satisfies a certain differential equation associated to the Stein characterisation. We use this approach to prove that all Stein operators with linear coefficients characterise their target distribution, and verify on a case-by-case basis that all polynomial Stein operators in the literature with coefficients of degree at most two are characterising. For X denoting a standard Gaussian random variable and Hp the p-th Hermite polynomial, we also prove, amongst other examples, that the Stein operators for Hp(X), p = 3; 4; : : : ; 8, with coefficients of minimal possible degree characterise their target distribution, and that the Stein operators for the products of p = 3; 4; : : : ; 8 independent standard Gaussian random variables are characterising (in both settings the Stein operators for the cases p = 1; 2 are already known to be characterising). We leverage our Stein characterisations of H3(X) and H4(X) to derive characterisations of these target distributions in terms of iterated Gamma operators from Malliavin calculus, that are natural in the context of the Malliavin-Stein method