Faster parameter estimation using risk-sensitive filters

In this paper, we propose a risk-sensitive approach to parameter estimation for hidden Markov models (HMMs). The parameter estimation approach considered exploits estimation of various functions of the state, based on model estimates. We propose certain practical suboptimal risk-sensitive filters to estimate the various functions of the state during transients, rather than optimal risk-neutral filters as in earlier studies. The estimates are asymptotically optimal, if asymptotically risk neutral, and can give significantly improved transient performance, which is a very desirable objective for certain engineering applications. To demonstrate the improvement in estimation simulation studies are presented that compare parameter estimation based on risk-sensitive filters with estimation based on risk-neutral filters.

The relationship between 'reasonably practicable'and risk management regulation

This paper examines two concepts which are central to contemporary standard setting in occupational health and safety (OHS) regulation, and explores the differences and similarities between these concepts – the notion of ‘reasonably practicable’ which qualifies the ‘general duties’ and some other provisions in the Australian OHS standards, and the risk management requirements typically found in OHS regulations and approved codes of practice (advisory standards in Queensland).

Outsourcing risk -the regulation of occupational health and safety where subcontractors are employed

The subcontracting out of production tasks and services is not a new phenomenon, but from the late 1970s, and more especially over the last 15years, the practice-now frequently referred to as outsourcing-has grown substantially across a range of industries in most industrialized countries.Recent surveys undertaken in the United States,Europe,and Australia have all identified a rapid increase in outsourcing/subcontracting, especially amongst large private and public sector organizations. The Second Australian Workplace Industrial Relations Survey found that the number of contractors, agency workers, outworkers, and volunteers had increased by almost 40% in the last 5 years to 1997 with contracting out more common in the public sector than the private sector. Outsourcing has become a major tool by which large organizations have sought to increase competitiveness/cut costs, bypass regulatory controls, and secure more flexible employment arrangements.

OHS inspectors and psychosocial risk factors: Evidence from Australia

Legislation giving prominence to psychosocial risk factors at work has changed the role of government occupational health and safety (OHS) inspectors in many countries. Yet little is known about how inspectorates have responded to these changes. Between 2003 and 2007 an Australian study was undertaken on OHS standards, entailing detailed documentary analysis, interviews with 36 inspectorate managers and 89 inspectors, and observations made when researchers accompanied inspectors on 120 typical workplace visits. Our study found that general duty provisions in OHS legislation clearly incorporated psychosocial hazards and inspectorates had introduced guidance material, pursued campaigns and increased interventions in this area. However, the regulatory framework remained narrow (focused on bullying/harassment, occupational violence and work stress) and workplace visits revealed psychosocial hazards as a marginal area of inspectorate activity. These findings were reinforced in interviews. While aware of psychosocial hazards inspectors often saw the issue as problematic due to limited training, resourcing constraints, deficiencies in regulation and fears of victimisation amongst workers. In order to address these problems a number of changes are required that recognize the distinctiveness of psychosocial hazards including their ‘invisibility’. Notable here are revisions to regulation (both general duty provisions and specific codes), the development of comprehensive guidance and assessment tools to be used by inspectors, greater use of procedural enforcement, and enhanced inspectorate resourcing and training. There is also a need to recognize complex inter-linkages between psychosocial hazards and the industrial relations context.

Flood victim’s heartbreak : ‘don’t be complacent about the risk’

"No one had higher stakes in the findings of the Queensland Floods Commission of Inquiry than Grantham father Matthew Keep, whose mother, mother-in-law and baby daughter, Jessica, died at Grantham that terrible day in January. For seven months he has read every statement, submission, running log, disaster management plan and media article available. As he has comforted his grieving wife, Stacy, helped care for his two young children Madison, 5, and Jacob, 4, who amazingly survived the flood, and welcomed a new baby into the family, Matthew has searched for answers for himself and his community. Why were authorities not able to warn people in seven towns in Toowoomba and the Lockyer Valley that the worst flash flooding in at least a century was about to strike, killing 22 people? How could such a sudden and catastrophic flood claim three members of his family within minutes?"

Predicting the likelihood of non-healing : a venous leg ulcer risk assessment tool

This project developed, validated and tested reliability of a risk assessment tool to predict the risk of failure to heal of patients with venous leg ulcers within 24 weeks. The risk assessment tool will allow clinicians to be able to determine realistic outcomes for their patients, promote early healing and potentially avoid weeks of inappropriate therapy. The tool will also assist in addressing specific risk factors and guide decisions on early, alternative, tailored interventions.

Gliptins - do they increase cardiovascular risk or benefit?

INTRODUCTION: In 2008, the US FDA required all new glucose-lowering therapies to show cardiovascular safety, and this applies to the dipeptidyl peptidase-4 inhibitors ('gliptins'). AREAS COVERED: The cardiovascular safety trials of saxagliptin and alogliptin have recently been published and are the subject of this evaluation. EXPERT OPINION: The Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus - Thrombolysis in Myocardial Infarction 53 trial and Examination of Cardiovascular Outcomes with Alogliptin versus Standard of Care were both multicentre, randomised, double-blind, placebo-controlled, Phase IV clinical trials. These trials showed that saxagliptin and alogliptin did not increase the primary end point, which was a composite of cardiovascular outcomes that did not include hospitalisations for heart failure. However, saxagliptin significantly increased hospitalisation for heart failure, which was a component of the secondary end point. The effect of alogliptin on hospitalisations for heart failure has not been reported. Neither agent improved cardiovascular outcomes. As there is no published evidence of improved outcomes with gliptins, it is unclear to us why these agents are so widely available for use. We suggest that the use of gliptins be restricted to Phase IV clinical trials until such time as cardiovascular safety and benefits/superiority are clearly established

Prevalence of malnutrition, obesity and nutritional risk of Australian paediatric inpatients: A national one-day snapshot

Aim Low prevalence rates of malnutrition at 2.5% to 4% have previously been reported in two tertiary paediatric Australian hospitals. The current study is the first to measure the prevalence of malnutrition, obesity and nutritional risk of paediatric inpatients in multiple hospitals throughout Australia. Methods Malnutrition, obesity and nutritional risk prevalence were investigated in 832 and 570 paediatric inpatients, respectively, in eight tertiary paediatric hospitals and eight regional hospitals across Australia on a single day. Malnutrition and obesity prevalence was determined using z-scores and body mass index (BMI) percentiles. High nutritional risk was determined as a Paediatric Yorkhill Malnutrition Score of 2 or more. Results The prevalence rates of malnourished, wasted, stunted, overweight and obese paediatric patients were 15%, 13.8%, 11.9%, 8.8% and 9.9%, respectively. Patients who identified as Aboriginal and Torres Strait Islander were more likely to have lower height-for-age z-scores (P < 0.01); however, BMI and weight-for-age z-scores were not significantly different. Children who were younger, from regional hospitals or with a primary diagnosis of cardiac disease or cystic fibrosis had significantly lower anthropometric z-scores (P = 0.05). Forty-four per cent of patients were identified as at high nutritional risk and requiring further nutritional assessment. Conclusions The prevalence of malnutrition and nutritional risk of Australian paediatric inpatients on a given day was much higher when compared with the healthy population. In contrast, the proportion of overweight and obese patients was less.

Activity patterns of preschool-aged children at risk for obesity

BACKGROUND Although the prevalence of obesity in young children highlights the importance of early interventions to promote physical activity (PA), there are limited data on activity patterns in this age group. The purpose of this study is to describe activity patterns in preschool-aged children and explore differences by weight status. METHODS Analyses use baseline data from Healthy Homes/Healthy Kids- Preschool, a pilot obesity prevention trial of preschool-aged children overweight or at risk for overweight. A modified parent-reported version of the previous-day PA recall was used to summarize types of activity. Accelerometry was used to summarize daily and hourly activity patterns. RESULTS "Playing with toys" accounted for the largest proportion of a child's previous day, followed by "meals and snacks", and "chores". Accelerometry-measured daily time spent in sedentary behavior, light PA, and moderate-to-vigorous PA (MVPA) was 412, 247, and 69 minutes, respectively. Percent of hourly time spent in MVPA ranged from 3% to 13%, peaking in the late morning and evening hours. There were no statistically significant MVPA differences by weight status. CONCLUSIONS This study extends our understanding of activity types, amounts, and patterns in preschool-age children and warrants further exploration of differences in physical activity patterns by weight status.

Corporate governance and bankruptcy risk

We examine how firm characteristics, particularly the degree of firm complexity and the firm’s need for specialty knowledge, affect the relationship between corporate governance and the risk of bankruptcy. We find that having larger boards reduces the risk of bankruptcy only for complex firms. Our results also suggest that the proportion of inside directors on the board is inversely associated with the risk of bankruptcy in firms that require more specialist knowledge, and that the reverse is true in technically unsophisticated firms. The results further reveal that the additional explanatory power from corporate governance variables becomes stronger as the time to bankruptcy is increased, implying that although corporate governance variables are important predictors, governance changes are likely to be too late to save a firm on the verge of bankruptcy.

The effect of deprivation and disease-severity on malnutrition risk in chronic obstructive pulmonary disease (COPD)

Deprivation has previously been shown to be an independent risk factor for the high prevalence of malnutrition observed in COPD (Collins et al., 2010). It has been suggested the socioeconomic gradient observed in COPD is greater than any other chronic disease (Prescott & Vestbo, 1999). The current study aimed to examine the infl uence of disease severity and social deprivation on malnutrition risk in outpatients with COPD. 424 COPD outpatients were screened using the ‘Malnutrition Universal Screening Tool’ (‘MUST’). COPD disease severity was recorded in accordance with the GOLD criteria and deprivation was established according to the patient’s geographical location (postcode) at the time of nutritional screening using the UK Government’s Index of Multiple Deprivation (IMD). IMD ranks postcodes from 1 (most deprived) to 32,482 (least deprived). Disease severity was posi tively associated with an increased prevalence of malnutrition risk (p < 0.001) both within and between groups, whilst rank IMD was negatively associated with malnutrition (p = 0.020), i.e. those residing in less deprived areas were less likely to be malnourished. Within each category of disease severity the prevalence of malnutrition was two-fold greater in those residing in the most deprived areas compared to those residing in the least deprived areas. This study suggests that deprivation and disease severity are independent risk factors for malnutrition in COPD both contributing to the widely variable prevalence of malnutrition. Consideration of these issues could assist with the targeted nutritional management of these patients.

Medical negligence, causation and liability for non-disclosure of risk : a post-wallace framework and critique

Through an examination of Wallace v Kam, this article considers and evaluates the law of causation in the specific context of a medical practitioner’s duty to provide information to patients concerning material risks of treatment. To supply a contextual background for the analysis which follows, Part II summarises the basic principles of causation law, while Part III provides an overview of the case and the reasoning adopted in the decisions at first instance and on appeal. With particular emphasis upon the reasoning in the courts of appeal, Part IV then examines the implications of the case in the context of other jurisprudence in this field and, in so doing, provides a framework for a structured consideration of causation issues in future non-disclosure cases under the Australian civil liability legislation. As will become clear, Wallace was fundamentally decided on the basis of policy reasoning centred upon the purpose behind the legal duty violated. Although the plurality in Rogers v Whitaker rejected the utility of expressions such as ‘the patient’s right of self-determination’ in this context, some Australian jurisprudence may be thought to frame the practitioner’s duty to warn in terms of promoting a patient’s autonomy, or right to decide whether to submit to treatment proposed. Accordingly, the impact of Wallace upon the protection of this right, and the interrelation between it and the duty to warn’s purpose, is investigated. The analysis in Part IV also evaluates the courts’ reasoning in Wallace by questioning the extent to which Wallace’s approach to liability and causal connection in non-disclosure of risk cases: depends upon the nature and classification of the risk(s) in question; and can be reconciled with the way in which patients make decisions. Finally, Part V adopts a comparative approach by considering whether the same decision might be reached if Wallace was determined according to English law.

Incidence, risk factors and estimates of a woman's risk of developing secondary lower limb lymphedema and lymphedema-specific supportive care needs in women treated for endometrial cancer

Objectives: Few studies have assessed the risk and impact of lymphedema among women treated for endometrial cancer. We aimed to quantify cumulative incidence of, and risk factors for developing lymphedema following treatment for endometrial cancer and estimate absolute risk for individuals. Further, we report unmet needs for help with lymphedema-specific issues. Methods: Women treated for endometrial cancer (n = 1243) were followed-up 3–5 years after diagnosis; a subset of 643 completed a follow-up survey that asked about lymphedema and lymphedema-related support needs. We identified a diagnosis of secondary lymphedema from medical records or self-report. Multivariable logistic regression was used to evaluate risk factors and estimates. Results: Overall, 13% of women developed lymphedema. Risk varied markedly with the number of lymph nodes removed and, to a lesser extent, receipt of adjuvant radiation or chemotherapy treatment, and use of nonsteroidal anti-inflammatory drugs (pre-diagnosis). The absolute risk of developing lymphedema was > 50% for women with 15 + nodes removed and 2–3 additional risk factors, 30–41% for those with 15 + nodes removed plus 0–1 risk factors or 6–14 nodes removed plus 3 risk factors, but ≤ 8% for women with no nodes removed or 1–5 nodes but no additional risk factors. Over half (55%) of those who developed lymphedema reported unmet need(s), particularly with lymphedema-related costs and pain. Conclusion: Lymphedema is common; experienced by one in eight women following endometrial cancer. Women who have undergone lymphadenectomy have very high risks of lymphedema and should be informed how to self-monitor for symptoms. Affected women need greater levels of support.

The unequal distribution of road trauma in China : understanding risk factors to improve public health

The World Health Organization identifies road trauma as a major public health issue in every country; most notably among low-to-middle income countries. More than 90% of all road fatalities occur in these countries, although they have only 48% of all registered vehicles [1]. Unprecedented focus has been placed on reducing the global road trauma burden through the United Nations Decade of Action for Road Safety (2011-2020). China is rapidly transitioning from a nation of bicycle riders and pedestrians to one where car ownership and use is increasing. This transition presents important public health, mobility, and safety challenges. Rapid motorisation has resulted in an increased road trauma burden, shouldered disproportionately among the population. Vulnerable road users (bicyclists, pedestrians, and motorcyclists) are of particular concern, representing 70% of all road-related fatalities [1]. Furthermore, those at greatest risk of sustaining a crash-related disability are: male, older, less educated, and earning a lower income [2] and residing in urban areas [3], with higher fatality rates in north-western poorer provinces [3]. Speeding is a key factor in road crashes in China [1, 4] and is one of two risk factors targeted in the Bloomberg Philanthropies-funded Global Road Safety Program operating in two Chinese cities over five year [5] to which the first author has provided expert advice. However, little evidence exists to help understand the factors underpinning speeding behaviour. Previous research conducted by the authors in Beijing and Hangzhou explored personal, social, and legal factors relating to speeding to assist in better understanding the motivations for non-compliance with speed limits. Qualitative and quantitative research findings indicated that speeding is relatively common, including self-reported travel speeds of greater than 30 km/hour above posted speed limits [6], and that the road safety laws and enforcement practices may, in some circumstances, contribute to this [7]. Normative factors were also evident; the role of friends, family members and driving instructors were influential. Additionally, using social networks to attempt to avoid detection and penalty was reported, thereby potentially reinforcing community perceptions that speeding is acceptable [8, 9]. The authors established strong collaborative links with the Chinese Academy of Sciences and Zhejiang Police College to conduct this research. The first author has worked in both institutions for extended time periods and recognises that research must include an understanding of culturally-relevant issues if road safety is to improve in China. Future collaborations to assist in enhancing our understanding of such issues are welcomed. References [1] World Health Organization. (2009). Global status report on road safety: Time for action; Geneva. [2] Chen, H., Du, W., & Li, N. (2013). The socioeconomic inequality in traffic-related disability among Chinese adults: the application of concentration index. Accident Analysis & Prevention, 55(101-106). [3] Wang, S. Y., Li, Y. H., Chi, G. B., Xiao, S. Y., Ozanne-Smith, J., Stevenson, M., & Phillips, M. (2008). Injury-related fatalities in China: an under-recognised public-health problem. The Lancet (British edition), 372(9651), 1765-1773. [4] He, J., King, M. J., Watson, B., Rakotonirainy, A., & Fleiter, J. J. (2013). Speed enforcement in China: National, provincial and city initiatives and their success. Accident Analysis & Prevention, 50, 282-288. [5] Bhalla, K., Li, Q., Duan, L., Wang, Y., Bishai, D., & Hyder, A. A. (2013). The prevalence of speeding and drink driving in two cities in China: a mid project evaluation of ongoing road safety interventions. Injury, 44, 49-56. doi:10.1016/S0020-1383(13)70213-4. [6] Fleiter, J. J., Watson, B., & Lennon, A. (2013). Awareness of risky behaviour among Chinese drivers. Peer-reviewed paper presented at 23rd Canadian Multidisciplinary Road Safety Conference, Montréal, Québec. [7] Fleiter, J. J., Watson, B., Lennon, A., King, M. J., & Shi, K. (2009). Speeding in Australia and China: A comparison of the influence of legal sanctions and enforcement practices on car drivers. Peer-reviewd paper presented at Australasian Road Safety Research Policing Education Conference, Sydney. [8] Fleiter, J. J., Watson, B., Lennon, A., King, M. J., & Shi, K. (2011). Social influences on drivers in China. Journal of the Australasian College of Road Safety, 22(2), 29-36. [9] Fleiter, J. J., Watson, B., Guan, M. Q., Ding, J. Y., & Xu, C. (2013). Characteristics of Chinese Drivers Attending a Mandatory Training Course Following Licence Suspension. Peer-reviewed paper presented at Road Safety on Four Continents, Beijing, China.

Multilevel competing risk models to evaluate the risk of nosocomial infection

Introduction Risk factor analyses for nosocomial infections (NIs) are complex. First, due to competing events for NI, the association between risk factors of NI as measured using hazard rates may not coincide with the association using cumulative probability (risk). Second, patients from the same intensive care unit (ICU) who share the same environmental exposure are likely to be more similar with regard to risk factors predisposing to a NI than patients from different ICUs. We aimed to develop an analytical approach to account for both features and to use it to evaluate associations between patient- and ICU-level characteristics with both rates of NI and competing risks and with the cumulative probability of infection. Methods We considered a multicenter database of 159 intensive care units containing 109,216 admissions (813,739 admission-days) from the Spanish HELICS-ENVIN ICU network. We analyzed the data using two models: an etiologic model (rate based) and a predictive model (risk based). In both models, random effects (shared frailties) were introduced to assess heterogeneity. Death and discharge without NI are treated as competing events for NI. Results There was a large heterogeneity across ICUs in NI hazard rates, which remained after accounting for multilevel risk factors, meaning that there are remaining unobserved ICU-specific factors that influence NI occurrence. Heterogeneity across ICUs in terms of cumulative probability of NI was even more pronounced. Several risk factors had markedly different associations in the rate-based and risk-based models. For some, the associations differed in magnitude. For example, high Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were associated with modest increases in the rate of nosocomial bacteremia, but large increases in the risk. Others differed in sign, for example respiratory vs cardiovascular diagnostic categories were associated with a reduced rate of nosocomial bacteremia, but an increased risk. Conclusions A combination of competing risks and multilevel models is required to understand direct and indirect risk factors for NI and distinguish patient-level from ICU-level factors.