A Weighted Composite Dose – Response Model For Human Salmonellosis

This article describes the development of a weighted composite dose – response model for human salmonellosis. Data from previously reported human challenge studies were categorized into two different groups representing low and moderately virulent/pathogenic Salmonella strains based on a disease end point. Because epidemiological data indicate that some Salmonella strains are particularly pathogenic, and in the absence of human feeding study data for such strains, Shigella dysenteriae was used as a proxy for highly virulent strains. Three single-hit dose – response models were applied to the human feeding study data and evaluated for best fit using maximum likelihood estimation: (1) the exponential (E-1pop), (2) the two-subpopulation exponential (E-2pop), and (3) the Beta-Poisson (BP). Based on the goodness-of-fit test, the E-1pop and BP were the best-fit models for low and moderately virulent/pathogenic Salmonella strains, and the E-2pop and BP models were better for highly virulent/pathogenic strains. Epistemic analysis was conducted by determining the degree of confidence associated with the selected models, which was found to be 50%/50% (E-1pop/BP) for low and moderately pathogenic Salmonella strains, and 9.8%/90.2% (E-2pop/BP) for highly virulent strains. The degree of confidence for each component model and variations in the proportion of strains within each virulence/pathogenicity category were incorporated into the overall composite model. This study describes the influence of variation in strain virulence and host susceptibility on the shape of the population dose – response relationship.     

Risk minimization for an insurer with investment and reinsurance via g-expectation

Abstract

This paper is devoted to the study of a risk-based optimal investment and proportional reinsurance problem. The surplus process of the insurer and the risky asset process in the financial market are assumed to be general jump-diffusion processes. We use a convex risk measure generated by g-expectation to describe the risk of the terminal wealth with investment and reinsurance. Under the aim of minimizing the risk, the problem is solved by using techniques of stochastic maximum principles. Two interesting special cases are studied and the explicit expressions for optimal strategies and corresponding minimal risks are derived.     

Neither Silent nor Invisible: A Comparison of Two Participative Projects Involving Older Lesbians and Gay Men in the United Kingdom

This article offers a comparative review of two participative projects involving older lesbians and gay men (OLG) in different parts of the United Kingdom. Both projects set out to promote local networks of OLGs, support and facilitate their input and commentary on local services and act as a prototype model of consultation that might be taken up and used in other areas. The authors review some of the challenges and achievements of each project and critically compare the two initiatives. Discussion of each stage of the projects includes an appraisal of the relative strengths and weaknesses of their different elements. Emphasis is placed upon the concern to involve OLGs at every level and stage of each project and how this was achieved. Reference to relevant policy provides a backdrop to a discussion of the practical considerations in setting up time-limited projects of this nature. Consideration of some of the outcomes of each project with emphasis upon the implications for utilising similar participative approaches in future consultation and inclusion initiatives is provided.     

Consumer-Phase Salmonella enterica serovar Enteritidis Risk Assessment for Egg-Containing Food Products

We describe a one-dimensional probabilistic model of the role of domestic food handling behaviors on salmonellosis risk associated with the consumption of eggs and egg-containing foods. Six categories of egg-containing foods were defined based on the amount of egg contained in the food, whether eggs are pooled, and the degree of cooking practiced by consumers. We used bootstrap simulation to quantify uncertainty in risk estimates due to sampling error, and sensitivity analysis to identify key sources of variability and uncertainty in the model. Because of typical model characteristics such as nonlinearity, interaction between inputs, thresholds, and saturation points, Sobol's method, a novel sensitivity analysis approach, was used to identify key sources of variability. Based on the mean probability of illness, examples of foods from the food categories ranked from most to least risk of illness were: (1) home-made salad dressings/ice cream; (2) fried eggs/boiled eggs; (3) omelettes; and (4) baked foods/breads. For food categories that may include uncooked eggs (e.g., home-made salad dressings/ice cream), consumer handling conditions such as storage time and temperature after food preparation were the key sources of variability. In contrast, for food categories associated with undercooked eggs (e.g., fried/soft-boiled eggs), the initial level of Salmonella contamination and the log10 reduction due to cooking were the key sources of variability. Important sources of uncertainty varied with both the risk percentile and the food category under consideration. This work adds to previous risk assessments focused on egg production and storage practices, and provides a science-based approach to inform consumer risk communications regarding safe egg handling practices.     

Challenging perceptions of disability through performance poetry methods: the ‘Seen but Seldom Heard’ project

This paper considers performance poetry as a method to explore lived experiences of disability. We discuss how poetic inquiry used within a participatory arts-based research framework can enable young people to collectively question society’s attitudes and actions towards disability. Poetry will be considered as a means to develop a more accessible and effective arena in which young people with direct experience of disability can be empowered to develop new skills that enable them to tell their own stories. Discussion of how this can challenge audiences to critically reflect upon their own perceptions of disability will also be developed.     

Mixing Bismarck and child pension systems: an optimum taxation approach

Pensions with a strong tax–benefit link (Bismarck pensions) minimise the labour–leisure distortion of the public pension system. By contrast, pensions with a strong link of benefits to the number of children (child pensions) minimise the fertility distortion. When both types of distortion are present, we obtain a Corlett–Hague result regarding the optimal mix of the two pension formulae: the Bismack pension should be given a positive weight if and only if children are more complementary to leisure than consumption. Alternative fertility instruments such as child benefits turn out to be perfect substitutes to a child pension.     

Consumer Phase Risk Assessment for Listeria monocytogenes in Deli Meats

The foodborne disease risk associated with the pathogen Listeria monocytogenes has been the subject of recent efforts in quantitative microbial risk assessment. Building upon one of these efforts undertaken jointly by the U.S. Food and Drug Administration and the U.S. Department of Agriculture (USDA), the purpose of this work was to expand on the consumer phase of the risk assessment to focus on handling practices in the home. One-dimensional Monte Carlo simulation was used to model variability in growth and cross-contamination of L. monocytogenes during food storage and preparation of deli meats. Simulations approximated that 0.3% of the servings were contaminated with >10(4) CFU/g of L. monocytogenes at the time of consumption. The estimated mean risk associated with the consumption of deli meats for the intermediate-age population was approximately 7 deaths per 10(11) servings. Food handling in homes increased the estimated mean mortality by 10(6)-fold. Of all the home food-handling practices modeled, inadequate storage, particularly refrigeration temperatures, provided the greatest contribution to increased risk. The impact of cross-contamination in the home was considerably less. Adherence to USDA Food Safety and Inspection Service recommendations for consumer handling of ready-to-eat foods substantially reduces the risk of listeriosis.     

Practising partnership--participative inquiry with older people

This paper examines the importance of approaching research with minority groups of older people in an inclusive way. For older people, ageism is a key feature of the discrimination and marginalisation they experience, but some are excluded and marginalised further on the basis of their ethnicity and sexuality. The 'invisibility' of these groups poses a challenge to social workers and social work educators, as assumptions about their experiences and needs may be made which do not reflect the subjective experiences of these older people. The use of Participatory Action Research as a method of including service users in knowledge and theory development will be analysed, and a research proposal undertaken in partnership with a local voluntary agency will be explored. The importance for social work education of pursuing 'inclusive' methods of research so that service users have more power over knowledge produced about their lives, will be discussed.     

Pensions and fertility: back to the roots

Fertility has long been declining in industrialised countries and the existence of public pension systems is considered as one of the causes. This paper provides detailed evidence on the mechanism by which a public pension system depresses fertility, based on historical data. Our theoretical framework highlights that the effect of a public pension system on fertility is ex ante ambiguous while its size is determined by the internal rate of return of the pension system. We identify an overall negative effect of the introduction of pension insurance on fertility using regional variation across 23 provinces of Imperial Germany in key variables of Bismarck’s pension system, which was introduced in Imperial Germany in 1891. The negative effect on fertility is robust to controlling for the traditional determinants of the first demographic transition as well as to other policy changes.     

Economic Well-being and Ageing: The Need for Financial Education for Social Workers

This paper explores the importance of financial education for social workers who are often working with individuals and families who are financially vulnerable and who frequently have little financial knowledge. This may be particularly relevant in light of the recent global recession and the negative impact this has had for many in terms of increased living costs and decreased income. Older people may be particularly vulnerable to the economic fluctuations caused by the recession, yet they may be disadvantaged further by poor understanding of the impact of finances on well-being from social care agencies, and a paucity of information and advice to enable them to develop improved financial literacy. This may be compounded further by increasingly strict eligibility criteria, which restrict access to services, leading to increasing numbers of older people who need to fund their own care. The objective of this paper is to highlight the need for students and practitioners to develop their own financial literacy skills so as to better enable them to support those that they work with. The discussion considers the usefulness of the ‘asset vulnerability framework’ devised by Moser in assessing the economic well-being of older people and its applicability within social work education and practice.