Acute rheumatic fever associated with household crowding in a developed country

Background: Acute rheumatic fever (ARF) and its sequelae, chronic rheumatic heart disease, remain important causes of morbidity and mortality worldwide, but there is little recent information about risk factors. The aim of this study was to examine the association between ARF and household crowding in New Zealand between 1996 and 2005.

Methods: This ecologic study used hospitalization data and census data to calculate incidence rates by census area unit (CAU). Rates of ARF were examined in relation to individual factors (age, ethnicity) and area factors based on the CAU of home address (household crowding, New Zealand deprivation index, household income, and proportion of children aged 5–14 years). The multivariate relationship between ARF incidence and CAU-based variables was assessed using a zero-inflated negative binomial model.

Results: This study included 1249 new cases of ARF between 1996 and 2005. At the univariate level, ARF rates were associated with household crowding across all age groups and ethnicities. ARF rates were significantly and positively related to household crowding after controlling for age, ethnicity, household income, and the density of children in the neighborhood. The incidence rate ratio was 1.065 (95% confidence interval, 1.052–1.079) for the total population.

Conclusions: In New Zealand, ARF rates are associated with household crowding at the CAU level. This finding supports action to reduce household crowding to improve health and reduce health inequalities. Our conclusion could be further investigated using a case-control study.

Sacrificial girls : a case study of the impact of streaming and setting on gender reform

This article reports on research funded by the Australian Research Council to investigate school responses to gender equity. It addresses the efforts of a disadvantaged school to tackle what they perceived to be gender inequalities, but in the process of constructing a top-set and bottom-set/ stream class they are developing new forms of old inequalities and new forms of inequalities. This research indicates that despite popular assertions that girls’ education has become the priority of schools and education systems, girls are being further disadvantaged through attempts to implement market strategies coupled with gender reform agendas grounded in liberal notions of equity and relying on unsophisticated notions of affirmative action. In addition, this study highlights the extent to which a media-driven debate about boys’ education has influenced the constitution of boys as the ‘new disadvantaged’ with the capacity to determine the nature of gender reform agendas and programmes in schools.

Exponential stabilization for state and input delay systems via output feedback

This paper considers the exponential stabilization problem via static and dynamic output feedback controllers of linear systems with a time delay in both the state and input. By using a change of the state variable and combining with the Lyapunov-Krasovskii method, new sufficient conditions for exponential stabilization via static and dynamic output feedback controllers are proposed. The conditions are expressed in terms of matrix inequalities but with only one parameter needs to be tuned and therefore can be efficiently solved by incorporating an one-dimensional search method into the Matlab’s LMI toolbox. Two numerical examples are provided to illustrate the obtained results.

Observer-based controller design of time-delay systems with an interval time-varying delay

This paper considers the problem of designing an observer-based output feedback controller to exponentially stabilize a class of linear systems with an interval time-varying delay in the state vector. The delay is assumed to vary within an interval with known lower and upper bounds. The time-varying delay is not required to be differentiable, nor should its lower bound be zero. By constructing a set of Lyapunov–Krasovskii functionals and utilizing the Newton–Leibniz formula, a delay-dependent stabilizability condition which is expressed in terms of Linear Matrix Inequalities (LMIs) is derived to ensure the closed-loop system is exponentially stable with a prescribed α-convergence rate. The design of an observerbased output feedback controller can be carried out in a systematic and computationally efficient manner via the use of an LMI-based algorithm. A numerical example is given to illustrate the design procedure.

An examination of the mediating role of salt knowledge and beliefs on the relationship between socio-demographic factors and discretionary salt use: a cross-sectional study

Background Discretionary salt use varies according to socio-demographic factors. However, it is unknown whether salt knowledge and beliefs mediate this relationship. This study examined the direct and indirect effect of socio-demographic factors on salt knowledge and discretionary salt use in a sample of 530 Australian adults.

Methods An internet based cross-sectional survey was used to collect data for this study. Participants completed an online questionnaire which assessed their salt knowledge, beliefs and salt use behaviour. Mplus was used to conduct structural equation modelling to estimate direct and indirect effects.

Results The mean age of the participants was 49.2 years, and about a third had tertiary education. Discretionary salt use was inversely related to age (r=-0.11; p<0.05), and declarative salt knowledge (knowledge of factual information) scores (r = -0.17; p<0.01), but was positively correlated with misconceptions about salt (r = 0.09; p<0.05) and beliefs about the taste of salt (r = 0.51; p<0.001). Structural equation modelling showed age, education and gender were indirectly associated with the use of discretionary salt through three mediating pathways; declarative salt knowledge, misconceptions about salt and salt taste beliefs.

Conclusions Inequalities observed between socio-demographic groups in their use of discretionary salt use can potentially be reduced through targeted salt knowledge and awareness campaigns.

Commentary : Obesity - why governments must act

The commercial drivers of the obesity epidemic are so influential that obesity can be considered a robust sign of commercial success – consumers are buying more food, more cars, and more energy-saving machines (1). It is unlikely that these powerful economic forces will change sufficiently in response to consumer desires to eat less and move more, or to corporate desires to be more socially responsible. When the 'free market' creates substantial population detriments and health inequalities, government policies are needed to change the ground-rules in favour of population benefits.

Design of H∞ control of neural networks with time-varying delays

This paper deals with the H∞ control problem of neural networks with time-varying delays. The system under consideration is subject to time-varying delays and various activation functions. Based on constructing some suitable Lyapunov-Krasovskii functionals, we establish new sufficient conditions for H∞ control for two cases of time-varying delays: (1) the delays are differentiable and have an upper bound of the delay-derivatives and (2) the delays are bounded but not necessary to be differentiable. The derived conditions are formulated in terms of linear matrix inequalities, which allow simultaneous computation of two bounds that characterize the exponential stability rate of the solution. Numerical examples are given to illustrate the effectiveness of our results.

Observer-based control for time-varying delay neural networks with nonlinear observation

This paper studies the problem of designing observer-based controllers for a class of delayed neural networks with nonlinear observation. The system under consideration is subject to nonlinear observation and an interval time-varying delay. The nonlinear observation output is any nonlinear Lipschitzian function and the time-varying delay is not required to be differentiable nor its lower bound be zero. By constructing a set of appropriate Lyapunov-Krasovskii functionals and utilizing the Newton-Leibniz formula, some delay-dependent stabilizability conditions which are expressed in terms of Linear Matrix Inequalities (LMIs) are derived. The derived conditions allow simultaneous computation of two bounds that characterize the exponential stability rate of the closed-loop system. The unknown observer gain and the state feedback observer-based controller are directly obtained upon the feasibility of the derived LMIs stabilizability conditions. A simulation example is presented to verify the effectiveness of the proposed result.

Demographic and socio-cultural correlates of medical mistrust in two Australian states:Victoria and South Australia

Studies on medical mistrust have mainly focused on depicting the association between medical mistrust and access/utilization of healthcare services. The effect of broader socio-demographic and psycho-social factors on medical mistrust remains poorly documented. The study examined the effect of broader socio-demographic factors, acculturation, and discrimination on medical mistrust among 425 African migrants living in Victoria and South Australia, Australia. After adjusting for socio-demographic factors, low medical mistrust scores (i.e., more trusting of the system) were associated with refugee (β=−4.27, p<0.01) and family reunion (β=−4.01, p<0.01) migration statuses, being Christian (β=−2.21, p<0.001), and living in rural or village areas prior to migration (β=−2.09, p<0.05). Medical mistrust did not vary by the type of acculturation, but was positively related to perceived personal (β=0.43, p<0.001) and societal (β=0.38, p<0.001) discrimination. In order to reduce inequalities in healthcare access and utilisation and health outcomes, programs to enhance trust in the medical system among African migrants and to address discrimination within the community are needed.

A systematic review of studies examining the relationship between reported racism and health and wellbeing for children and young people

Racial discrimination is increasingly recognised as a determinant of racial and ethnic health inequalities, with growing evidence of strong associations between racial discrimination and adult health outcomes. There is a growing body of literature that considers the effects of racial discrimination on child and youth health. The aim of this paper is to provide a systematic review of studies that examine relationships between reported racial discrimination and child and youth health. We describe the characteristics of 121 studies identified by a comprehensive search strategy, including definitions and measurements of racial discrimination and the nature of reported associations. Most studies were published in the last seven years, used cross-sectional designs and were conducted in the United States with young people aged 12–18 years. African American, Latino/a, and Asian populations were most frequently included in these studies. Of the 461 associations examined in these studies, mental health outcomes (e.g. depression, anxiety) were most commonly reported, with statistically significant associations with racial discrimination found in 76% of outcomes examined. Statistically significant associations were also found for over 50% of associations between racial discrimination and positive mental health (e.g. self esteem, resilience), behaviour problems, wellbeing, and pregnancy/birth outcomes. The field is currently limited by a lack of longitudinal studies, limited psychometrically validated exposure instruments and poor conceptualisation and definition of racial discrimination. There is also a need to investigate the complex and varying pathways by which reported racial discrimination affect child and youth health. Ensuring study quality in this field will allow future research to reveal the complex role that racial discrimination plays as a determinant of child and youth health.

Developing an exploratory framework linking Australian Aboriginal peoples' connection to country and concepts of wellbeing

Aboriginal people across Australia suffer significant health inequalities compared with the non-Indigenous population. Evidence indicates that inroads can be made to reduce these inequalities by better understanding social and cultural determinants of health, applying holistic notions of health and developing less rigid definitions of wellbeing. The following article draws on qualitative research on Victorian Aboriginal peoples' relationship to their traditional land (known as Country) and its link to wellbeing, in an attempt to tackle this. Concepts of wellbeing, Country and nature have also been reviewed to gain an understanding of this relationship. An exploratory framework has been developed to understand this phenomenon focusing on positive (e.g., ancestry and partnerships) and negative (e.g., destruction of Country and racism) factors contributing to Aboriginal peoples' health. The outcome is an explanation of how Country is a fundamental component of Aboriginal Victorian peoples' wellbeing and the framework articulates the forces that impact positively and negatively on this duality. This review is critical to improving not only Aboriginal peoples' health but also the capacity of all humanity to deal with environmental issues like disconnection from nature and urbanisation.