No evidence that sperm morphology predicts paternity success in wild house wrens

Postcopulatory sexual selection (PCSS) in internally fertilizing vertebrates is a topic of great interest, yet relatively little is known about the characteristics of sperm and ejaculates that confer an advantage in PCSS. In this study, we investigated several measures of sperm morphology that potentially contribute to fertilization success under PCSS. We tested whether sperm morphology related to success in PCSS (via extra-pair paternity) in house wrens (Troglodytes aedon). We found no evidence that sperm morphology differed between extra-pair sires and the within-pair males they cuckolded, nor that sperm morphology correlated with the proportion of within-pair offspring sired, the number of extra-pair offspring sired, or the total annual reproductive success. Male behavioral strategies may affect the probability that their sperm compete with other males’ sperm and that their sperm succeed under competition. Effects of these behavioral strategies, as well as differences between males in sperm number, could mask the effects of sperm morphology on the outcome of PCSS. Despite moderate levels of extra-pair paternity, selection on sperm may be relatively weak in house wrens. Further work is needed to understand general patterns in how sperm morphology relates to fertilization success within species.     

Total employee involvement: Measures for success

Whether environmental management is successful depends partly on whether managers can actively involve employees in policy formulation and implementation. This not only generates shop floor support for environmental policy, it also makes use of employees' environmental knowledge and expertise. Based on eight detailed case studies of different Dutch companies, this article examines the involvement of employees in environmental management and the possibilities of enhancing this involvement. It shows how employee involvement can be promoted by improving employeemanagement interaction, promoting responsibility for the environment among middle management and individual employees, formulating supplementary policy, and introducing a number of concrete measures.     

Herbizide im Spannungsfeld zwischen Ökologie und Ökonomie

The Science of Nature - Effective weed control has always been one of the central problems in agriculture. With the increase in the size of farm units and the drop in the number of workers,...     

The rise and fall of new knowledge interests in the Dutch environmental movement

Summary Since the late 1960s concern about the pollution of our physical environment has grown into a social and political issue. In this process of increasing awareness, environmental activists have played a catalysing role in most Western countries. Moreover the environmentalists formulated an alternative set of ideas and strategies concerning the production and use of knowledge. These new knowledge interests were organised around three dimensions: cosmology, technology, and the organisation of knowledge production. On the basis of a case-study of Dutch environmentalism this paper tries to demonstrate how the articulation of these new knowledge interests of international scope actually occurred in the particular Dutch national setting. The analysis shows that many of the ideas brought forward in the course of time by Dutch environmentalists have been imported from abroad, especially from the United States, Great Britain and West Germany. However, the specific ways in which Dutch environmentalists have defined the content of their own knowledge interests have depended very much on the particularities of the political culture and socio-economic climate of the Netherlands, as well as the internal dynamics within the various environmental groups themselves.Dr Jacqueline Cramer was until very recently a member of staff in the Department of Science Dynamics at the University of Amsterdam. She has now moved to the TNO Centre for Technology and Policy Studies, P.O. Box 541, 7300 AM, Apeldoorn, The Netherlands. This paper forms part of a comparative study of the development of environmentalism in Sweden, Denmark and the Netherlands carried out in association with Ron Eyerman and Andrew Jamison of the University of Lund, Sweden.)     

A new approach to propellant formulation: minimizing life-cycle costs through science-based design

The traditional approach to developing propellants for specific gun applications relies heavily on trial and error. Candidate formulations must be made in small quantities and subjected to burning-rate measurements and small-scale vulnerability assessments. If the properties of these candidates fail to meet expectations, the process must be repeated. This approach, while historically unavoidable, is obviously inefficient in time and expense, but it also can generate considerable waste streams associated with unsuccessful formulations. With added considerations of life-cycle costs including environmental impact at all stages of development, use, and disposal, this traditional approach becomes increasingly unworkable. In this report a new approach is proposed which makes maximal use of scientific understanding embodied in models during the early phases of the propellant-development cycle. Through simple simulations, it is shown that this strategy can have a significant impact on the overall costs of the development process. In analogy to the DOE program to convert the nuclear-weapon stewardship from testing-based to science-based, we term the new approach "science-based design." It is argued that the modeling contribution to the propellant-development process is most efficiently implemented by subjecting candidate formulations to a hierarchy of models of different sophistication and input-data requirements, reserving the most rigorous models (usually the most data-intensive and least robust) for the most promising candidates. This new approach will require concentration and leveraging of resources toward the most critical early-phase development steps, but it may be the only credible strategy to reconcile the need for higher-performance weapons with the reality of declining resources.