Extinction times for a general birth, death and catastrophe process

The birth, death and catastrophe process is an extension of the birth-death process that incorporates the possibility of reductions in population of arbitrary size. We will consider a general form of this model in which the transition rates are allowed to depend on the current population size in an arbitrary manner. The linear case, where the transition rates are proportional to current population size, has been studied extensively. In particular, extinction probabilities, the expected time to extinction, and the distribution of the population size conditional on nonextinction (the quasi-stationary distribution) have all been evaluated explicitly. However, whilst these characteristics are of interest in the modelling and management of populations, processes with linear rate coefficients represent only a very limited class of models. We address this limitation by allowing for a wider range of catastrophic events. Despite this generalisation, explicit expressions can still be found for the expected extinction times.

Never-married childless women in Australia: Health and social circumstances in older age

A growing proportion of women reach older age without having married or having children. Assumptions that these older women are lonely, impoverished, and high users of social and health services are based on little evidence. This paper uses data from the Older cohort of the Australian Longitudinal Study on Women's Health to describe self-reported demographics, physical and emotional health, and use of services among 10,108 women aged 73-78, of whom 2.7% are never-married and childless. The most striking characteristic of this group is their high levels of education, which are associated with fewer reported financial difficulties and higher rates of private health insurance. There are few differences in self-reported physical or emotional health or use of health services between these and other groups of older women. Compared with older married women with children, they make higher use of formal services such as home maintenance and meal services, and are also more likely to provide volunteer services and belong to social groups. Overall, there is no evidence to suggest that these women are a problem group. Rather, it seems that their life experiences and opportunities prepare them for a successful and productive older age. (c) 2005 Elsevier Ltd. All rights reserved.

Science-policy in environmental and health risk assessment: if we cannot do without, can we do better?

How can empirical evidence of adverse effects from exposure to noxious agents, which is often incomplete and uncertain, be used most appropriately to protect human health? We examine several important questions on the best uses of empirical evidence in regulatory risk management decision-making raised by the US Environmental Protection Agency (EPA)'s science-policy concerning uncertainty and variability in human health risk assessment. In our view, the US EPA (and other agencies that have adopted similar views of risk management) can often improve decision-making by decreasing reliance on default values and assumptions, particularly when causation is uncertain. This can be achieved by more fully exploiting decision-theoretic methods and criteria that explicitly account for uncertain, possibly conflicting scientific beliefs and that can be fully studied by advocates and adversaries of a policy choice, in administrative decision-making involving risk assessment. The substitution of decision-theoretic frameworks for default assumption-driven policies also allows stakeholder attitudes toward risk to be incorporated into policy debates, so that the public and risk managers can more explicitly identify the roles of risk-aversion or other attitudes toward risk and uncertainty in policy recommendations. Decision theory provides a sound scientific way explicitly to account for new knowledge and its effects on eventual policy choices. Although these improvements can complicate regulatory analyses, simplifying default assumptions can create substantial costs to society and can prematurely cut off consideration of new scientific insights (e.g., possible beneficial health effects from exposure to sufficiently low 'hormetic' doses of some agents). In many cases, the administrative burden of applying decision-analytic methods is likely to be more than offset by improved effectiveness of regulations in achieving desired goals. Because many foreign jurisdictions adopt US EPA reasoning and methods of risk analysis, it may be especially valuable to incorporate decision-theoretic principles that transcend local differences among jurisdictions.

Political science and public administration: The saga of a difficult relationship

This paper is based on 'The perennial ugly duckling-public sector education in tertiary institutions before and after Coombs, an invited contribution on management education delivered at the Sydney Academics Symposium on the Coombs Commission in Retrospect, IPAA National Conference, 28 November 2001.

Preliminary experience of allied health assessments delivered face to face and by videoconference to a residential facility for elderly people

We investigated whether allied health assessments carried out via videoconferencing were comparable to assessments carried out face to face. Five allied health therapists (in dietetics, occupational therapy, physiotherapy, podiatry and speech pathology) conducted an assessment of 12 high-dependency residents both face to face and by videoconferencing. On a five-point Likert scale, the therapists' mean ratings for the efficiency and suitability of videoconferencing for assessment were significantly lower than for face to face. Their mean rating for the adequacy of their care plans was also significantly lower for videoconferencing than for face to face. However, in each case the dietician's assessments did not differ significantly between the two modalities. In 35 cases out of 60, two independent raters agreed that the therapists' care plans after the videoconferencing and face-to-face assessments were the same. However, the level of agreement between raters was only moderate (kappa=0.31). Despite the therapists' (natural) preference for face-to-face working, care plans formulated via videoconferencing were reasonably similar to those formulated in face-to-face assessment. Allied health assessments carried out by videoconferencing would therefore seem to be feasible.

Randomised controlled trial of health assessments for older Australian veterans and war widows

Objective: To assess the effect of home-based health assessments for older Australians on health-related quality of life, hospital and nursing home admissions, and death. Design: Randomised controlled trial of the effect of health assessments over 3 years. Participants and setting: 1569 community-living veterans and war widows receiving full benefits from the Department of Veterans' Affairs and aged 70 years or over were randomly selected in 1997 from 10 regions of New South Wales and Queensland and randomly allocated to receive either usual care (n = 627) or health assessments (n = 942). Intervention: Annual or 6-monthly home-based health assessments by health professionals, with telephone follow-up, and written report to a nominated general practitioner. Main outcome measures: Differences in health-related quality of life, admission to hospital and nursing home, and death over 3 years of follow-up. Results: 3-year follow-up interviews were conducted for 1031 participants. Intervention-group participants who remained in the study reported higher quality of life than control-group participants (difference in Physical Component Summary score, 0.90; 95% CI, 0.05-1.76; difference in Mental Component Summary score, 1.36; 95% CI, 0.40-2.32). There was no significant difference in the probability of hospital admission or death between intervention and control groups over the study period. Significantly more participants in the intervention group were admitted to nursing homes compared with the control group (30 v 7; P < 0.01). Conclusions: Health assessments for older people may have small positive effects on quality of life for those who remain resident in the community, but do not prevent deaths. Assessments may increase the probability of nursing-home placement.

The gender differences in health effects of environmental cadmium exposure and potential mechanisms

On a viewpoint of gender differences in Cd body burden and its health effects, we reviewed the population- based research including our own which conducted in Japan, Thailand, Australia, Poland, Belgium and Sweden to assess health effects of human exposure to environmental cadmium and their potential mechanisms. As a result, six risk factors in Cd health effects in women have been identified; ( 1) more serious type of renal tubular dysfunction, ( 2) difference in calcium metabolism and its regulatory hormones, ( 3) kidney sensitivity; difference in P450 phenotype, ( 4) pregnancy, ( 5) body iron store status, and ( 6) genetic factors. Further studies of Cd toxicity targeted to women would now appear necessary.

Sources of stress experienced by occupational therapists and social workers in mental health settings

This study examined the sources of stress experienced by occupational therapists and social workers employed in Australian public mental health services and identified the demographic and work-related factors related to stress using a cross-sectional survey design. Participants provided demographic and work-related information and completed the Mental Health Professionals Stress Scale. The overall response rate to the survey was 76.6%, consisting of 196 occupational therapists and 108 social workers. Results indicated that lack of resources, relationships and conflicts with other professionals, workload, and professional self-doubt were correlated with increased stress. Working in case management was associated with stress caused by client-related difficulties, lack of resources, and professional self-doubt. The results of this study suggest that Australian occupational therapists and social workers experience stress, with social workers reporting slightly more overall stress than occupational therapists. Copyright © 2005 Whurr Publishers Ltd.

Family, work and health - The impact of marriage, parenthood and employment on self-reported health of Australian men and women

We investigate multiple-burden and multiple-attachment hypotheses for the association among marriage, parenthood, employment and health for Australian men and women. Using longitudinal data from the Australian panel survey, 'Negotiating the Lifecourse', we find that men and women employed full time report better health than those employed part time or not employed. Previously married women report worse health than married women, but there is no association between marital status and health for men. We also find that men with preschool children in the household report worse health than men with older children, whereas women with preschool children report better health than women with older children. In addition for women we find evidence of a role-burden where combining full-time employment and children has a negative impact on health, but combining children with part-time or no employment has a beneficial health effect. There are no health effects of combining roles for men.

Smoking status of Australian general practice patients and their attempts to quit

This paper seeks to report on smoking rates, quit attempt methods and success rates among adult patients attending Australian general practice. A cluster cross-sectional survey was used to survey adult patients (18+), who attended Australian GPs in during 2002 and 2003. Over a quarter of patients (27.3%; 95% CI: 26.0-28.7) were former smokers and one in five (21.5%; 95% CI: 20.1-22.9) were current smokers. Ninety-two percent of former and 80% of current smokers used only one method in their last quit attempt with cold turkey the most common method used by both former (88%) and current (62%) smokers. Overall, success rates varied from 77% for cold turkey to 23% for bupropion. Success rates were re-analysed to consider quit attempts post-bupropion listing, with success rate for cold turkey reduced to 40% while bupropion remained reasonably constant at 21%. By tailoring smoking cessation interventions to a smokers' preparedness to quit, scope exists to increase the pool of smokers offered strategies that are more effective in achieving abstinence and avoiding relapse rather than relying on less effective self-quitting behaviours such as cold turkey. (c) 2005 Elsevier Ltd. All rights reserved.

Is discrepancy between actual and preferred work activities a factor in work-related stress for mental health occupational therapists and social workers

In the Western developed nations, the changing pattern of mental health care provision has necessitated mental health staff adopting new approaches to service delivery across a diverse and expanding range of service settings. The impact of changed service delivery on Australian mental health professionals is an area that has not been well studied. The aim of the study was to identify the current clinical work activities performed by occupational therapists and social workers and whether there was a discrepancy between the actual and preferred work activities. The study also aimed to identify whether any discrepancy between their actual and preferred clinical work activities was associated with higher levels of stress. A cross-sectional survey of 304 (response rate 76.6%) occupational therapists and social workers in Australian mental health services was conducted. A work activities scale developed specifically for this study and the Mental Health Professionals Stress Scale were used to measure actual and preferred work activities and stress respectively. Both groups experienced a discrepancy between their actual and preferred work activities, with the occupational therapists and the social workers mostly wanting to undertake a diverse range of activities to a significantly greater extent than they currently were. As predicted, stress was associated with the discrepancy between the kind of work that the participants wanted to do and the kind of work that their job actually entailed. Health workers require assistance to adapt to their new work roles and to achieve a balance between generic and discipline-specific competencies. This has implications for education and professional training.

Public and private psychiatry: Can they work together and is it worth the effort?

Objective: Partnerships in mental health care, particularly between public and private psychiatric services, are being increasingly recognized as important for optimizing patient management and the efficient organization of services. However, public sector mental health services and private psychiatrists do not always work well together and there seem to be a number of barriers to effective collaboration. This study set out to investigate the extent of collaborative 'shared care' arrangements between a public mental health service and private psychiatrists practising nearby. It also examined possible barriers to collaboration and some possible solutions to the identified problems. Method: A questionnaire examining the above factors was sent to all public sector mental health clinicians and all private psychiatrists in the area. Results: One hundred and five of the 154 (68.2%) public sector clinicians and 103 of the 194 (53.1%) private psychiatrists returned surveys. The main barriers to successful collaboration identified by members of both sectors were: 'Difficulty communicating' endorsed by 71.4% of public clinicians and 72% of private psychiatrists, 'Confusion of roles and responsibilities' endorsed by 62.9% and 66%, respectively, and 'Different treatment approach' by 47.6% and 45.6%, respectively. Over 60% of private psychiatrists identified problems with access to the public system as a barrier to successful shared care arrangements. It also emerged, as hypothesized, that the public and private systems tend to manage different patient populations and that public clinicians in particular are not fully aware of the private psychiatrists' range of expertise. This would result in fewer referrals for shared care across the sectors. Conclusions: A number of barriers to public sector clinicians and private psychiatrists collaborating in shared care arrangements were identified. The two groups surveyed identified similar barriers. Some of these can potentially be addressed by changes to service systems. Others require cultural shifts in both sectors. Improved communications including more opportunities for formal and informal meetings between people working in the two sectors would be likely to improve the understanding of the complementary sector's perspective and practice. Further changes would be expected to require careful work between the sectors on training, employment and practice protocols and initiatives, to allow better use of the existing services and resources.