The Economic Efficiency of Sampling Size: The Case of Beef Trim

The economically optimal sample size in a food safety test balances the marginal costs and marginal benefits of increasing the sample size. We provide a method for selecting the sample size when testing beef trim for Escherichia coli O157:H7 that equates the averted costs of recalls and health damages from contaminated meats sold to consumers with the increased costs of testing while allowing for uncertainty about the underlying prevalence rates of contamination. Using simulations, we show that, in most cases, the optimal sample size is larger than the current sample size of 60 and, in some cases, it exceeds 120. Moreover, lots with a lower prevalence rate have a higher expected damage because contamination is more difficult to detect. Our simulations indicate that these lots have a higher optimal sampling rate.     

A Simulation Study of Work-in-Process Inventory Drive Systems and their Effect on Operational Measurements

This simulation study compares three operational measures of performance through the exploration of three work-in-process (WIP) inventory drive systems and their associated inventory buffer characteristics. The three drive systems under study are a push, a pull and a hybrid push-pull system. While these systems have many aspects in common, their buffer management systems do not. The data analysis was based on information gathered from three computer-simulated flow shop assembly lines all operating in the same environment. Hypotheses concerning the operational performance measurements were established, independent variables were controlled and manipulated and a conclusion was drawn as to which system would afford the operation optimum results. While inventory has traditionally been considered and is currently being shown as an asset from an accounting point of view, it is obvious from the findings of this study, that excess WIP inventory, above the minimal requirements for production, may have a negative effect on the operational measurements evaluated.     

Where angels fear to tread: Richard Schoenherr (1935–1996)

Richard Schoenherr, professor of sociology at the University of Wisconsin — Madison, passed away unexpectedly on 9 January 1996. He is memorialized in this essay for his scholarly contributions in the areas of teaching, research, and service.     

Pubertal Timing,Depression, and Externalizing Problems: A Framework,Review, and Examination of Gender Differences

The purpose of this report is to synthesize the existing literature on pubertal timing and (a) depression and (b) externalizing behavior within a theoretical framework of risks, transitions, and psychological development during adolescence. This review first proposes a framework for considering pubertal timing and maladaptive behavior. Next, the literature on pubertal timing and depression is discussed, followed by the literature on pubertal timing and externalizing behavior with fine distinctions being made for males and females. Additionally, mediating and moderating variables are reviewed in an effort to understand mechanisms by which timing of puberty and maladjustment may operate or risk factors that may amplify the detrimental consequences of the pubertal transition. Finally, conclusions and future directions are proposed.     

The influence of riparian corridor width on ant and plant assemblages in northern Sydney,Australia

Protecting riparian corridors is a commonly applied environmental policy in urban landscapes. However, empirical data demonstrating their efficacy for biodiversity conservation outcomes is scarce. In this study we investigated whether riparian corridor width influences the diversity and community structure of ant (Hymenoptera: Formicidae) and vascular plant assemblages therein. Eighteen corridors of differing widths were selected from within the Ku-ring-gai Local Government Area, Sydney Australia. Ants were sampled using pitfall traps positioned within rectangular vegetation transects (30 × 10 m). Both ant and plant species richness, when standardised for sampling effort, were unrelated to riparian corridor width. However, significant compositional differences between sites were evident with increased width up to ~50 m. Narrow corridors contained greater abundances of opportunistic ant species and higher proportions of exotic plants. We interpret this to be the result of the greater disturbance/edge influence derived from adjacent upland urban environments. Site beta diversity did not increase with corridor width, suggesting that the exclusion of novel upslope habitats in narrow riparian corridors is not a significant cause of community assemblage modification at these sites. To minimise the impact of deleterious edge effects on ant fauna, environmental managers should seek to retain riparian corridors wider than ~50 m. However, we observed substantial between-site variability of biotic assemblages, irrespective of corridor width. Therefore we recommend that environmental management practice needs to take a catchment-wide approach and consider other parameters that may contribute to riparian health so as to optimise the protection of riparian biodiversity.     

Strategic planning for social and political change

Formalized planning is currently applied to planning for operations and capital investment, planning for products and markets, and occasionally for manpower. However, there is little evidence that companies are producing formal plans and programmes to deal with social and political change. Unfortunately, public opinion is moving against business, action groups inside and outside companies are challenging the authority of management, and public officials and politicians are already framing new laws and regulations. Unless managers begin to get more involved in the framing of these controls they are likely to find laws enacted and enforced by people who have little knowledge or sympathy with business. In this article the author points up the necessity to assess the social and political challenge to their business, and formulate and implement social and political strategies and plans aimed at ensuring the survival and prosperity of their organisations.