Using ergonomics in engineering design to improve health and safety

This paper outlines the importance of ergonomics in engineering design. It describes some of the cost benefits and principles underlying the application of ergonomics. The practical impact of the latter has become increasingly important in the light of European directives which are likely to have a substantial impact on the way engineers design. Three ergonomics case studies are described, the first two illustrate ways of identifying costs of poor ergonomics and the cost benefits of redesign using ergonomics principles. The third illustrates work which led to engineers redesigning assembly line workstations and ergonomics becoming an important part of manufacturing design. The background to this was concern about an increase in cases of Upper Limb Disorders (ULDs) and recognition that ergonomic advice was needed to find the source of problems and help in finding design options. Ergonomists were brought in and helped in identifying problems with workstations and tools. Final designs were developed by the company's own engineers based on the ergonomic study and reduced incidence of ULDs has been reported. Photographs showing examples before and after redesign can be found in the Health and Safety Executive's notes of guidance published in 1990, and some issues surrounding the nature of the detailed design solutions are discussed here. The impact of the ergonomics contribution resulted in engineers being trained in ergonomics so that it could be implemented on a routine basis throughout the site.     

Mitochondrial and nuclear DNA analysis of population subdivision among young-of-the-year Spanish mackerel (Scomberomorus maculatus) from the western Atlantic and Gulf of Mexico

The degree of population subdivision among collections of young-of-the-year (YOY) Spanish mackerel Scomberomorus maculatus sampled from along the Atlantic coast of the United States (Atlantic) and Gulf of Mexico (Gulf) was examined. Young-of-the-year were collected from spawning areas to minimize possible mixing among putative spawning stocks that may occur at later life history stages along migratory pathways or at over-wintering grounds. Restriction fragment length polymorphism (RFLP) analysis of the mitochondrial DNA (mtDNA) ND4 region and a nuclear actin intron was conducted. Collections in each of two years were analyzed to minimize bias associated with sampling at a single point in space or time. Substantial variation was detected at ND4 (haplotype diversity=0.81) and at the actin intron locus (gene diversity=0.21). Significant differences in gene diversity or allele frequencies were not detected among temporal samples at any of three locations. A homogeneous distribution of genetic variance among samples from widely spaced geographic regions was consistent with the hypothesis that Spanish mackerel comprise a single intermingling genetic stock. Power analysis showed that the mitochondrial analysis from this study was much more likely to detect population subdivision than analysis of the nuclear actin locus, despite lower mtDNA sample size. Received: 3 January 2000 / Accepted: 28 August 2000