Predictors of falling in older Maryland drivers: a structural-equation model

Falls can impair health and reduce quality of life among older adults. Although many factors are related to falling, few analyses examine causal models of this behavior. In this study, factors associated with falling were explored simultaneously using structural-equation modeling. A variety of cognitive, physical-performance, and health measures were administered to 694 older adult drivers from the state of Maryland. The observed and latent variables of age, cognitive ability, physical functioning, health, and falling behavior were used to create a causal model. The model revealed that being older was associated with declines in cognition, and such cognitive declines predicted increased falling. Similarly, poorer health was related to poorer physical functioning, which, in turn, also predicted increased falling. This model indicates that in addition to existing fall-prevention interventions aimed at improving physical functioning, interventions to improve cognition and health might also be effective. It is speculated that fear of falling, which often results in reduced mobility among older adults, might account for the lack of a direct relationship between age and falling. This hypothesis should be examined in further research.     

Urban bird conservation: presenting stakeholder-specific arguments for the development of bird-friendly cities

Following the call from the United Nations Convention on Biological Diversity “Cities & Biodiversity Outlook” project to better preserve urban biodiversity, this paper presents stakeholder-specific statements for bird conservation in city environments. Based upon the current urban bird literature we focus upon habitat fragmentation, limited habitat availability, lack of the native vegetation and vegetation structure as the most important challenges facing bird conservation in cities. We follow with an overview of the stakeholders in cities, and identify six main groups having the greatest potential to improve bird survival in cities: i) urban planners, urban designers and (landscape) architects, ii) urban developers and engineers, iii) homeowners and tenants, iv) companies and industries, v) landscaping and gardening firms, vi) education professionals. Given that motivation to act positively for urban birds is linked to stakeholder-specific advice, we present ten statements for bird-friendly cities that are guided by an action perspective and argument for each stakeholder group. We conclude with a discussion on how the use of stakeholder-specific arguments can enhance and rapidly advance urban bird conservation action.     

Representing employee requirements in labour tour scheduling

In this paper, we use the methodology of simulation to evaluate six approaches for handling employee requirements in an LP-based labour tour scheduling heuristic. We model employee requirements both as minimum acceptable staffing levels—where understaffing is unacceptable—and as target staffing levels—where both under- and overstaffing are acceptable. For each representation of employee requirements, we evaluate forms of the heuristic that use problem-specific and problem-independent information on the costs of employee surpluses and, if appropriate, employee shortages. Over an extensive test data set, the target-staffing approach using problem-specific cost information outperformed all other procedures. Specifically, it generated schedules costing less than 87% of those developed using the approach most commonly found in the literature. Its schedules were also almost 5% cheaper than those of its closest competitor. We discuss the managerial and research implications of the findings and provide suggestions for future research.