System dynamics as a systems-based problem-solving methodology

Systems dynamics is concerned with using systems ideas to increase understanding of various types of phenomena and to aid in the decision-making which determines action upon the processes involved. Developments within system dynamics have occurred mainly independently of advances in the broader systems movement. In this paper an attempt is made to bring to bear on system dynamics some recent work which considers the character of systems-based problem-solving methodologies. System dynamics is placed within a framework which enables the relative strengths and weaknesses of different approaches to be identified. This leads to a deeper understanding of some of the critiques of system dynamics and enables some issues to be outlined which may help to strengthen the theoretical base of system dynamics methodology and hence improve its ability to tackle practical situations.     

Development,plasticity and evolution of butterfly eyespot patterns

The developmental and genetic bases for the formation, plasticity and diversity of eyespot patterns in butterflies are examined. Eyespot pattern mutants, regulatory gene expression, and transplants of the eyespot developmental organizer demonstrate that eyespot position, number, size and colour are determined progressively in a developmental pathway largely uncoupled from those regulating other wing-pattern elements and body structures. Species comparisons and selection experiments suggest that the evolution of eyespot patterns can occur rapidly through modulation of different stages of this pathway, and requires only single, or very few, changes in regulatory genes.     

Developing a Design Science for the Use of Problem Structuring Methods

The considerable literature concerning problem structuring methods (PSMs) lacks, unfortunately, an understanding about how users gain relevant expertise. One element contributing to the acquisition of expertise is the availability of knowledge about standard practices. Making such knowledge about the use of PSMs accessible will therefore improve the support available to those seeking to gain or improve their expertise. It is argued here that viewing the use of PSMs as a Design Science provides a framework within which this knowledge may be formalised, evaluated, and presented. Knowledge within the Design Sciences is embodied in technological rules validated by field-testing in case studies and grounding against a suitable theoretical framework. Many examples of such rules centred on the models and representations used in PSMs are found in the existing literature. This is least helpful in showing how the methods are embedded in the broader context of intervention processes. Producing further, complementary rules focussed on this area of practice will both increase understanding of how PSMs are used and facilitate the acquisition of relevant expertise. This article identifies what these rules could consist of and suggests how they may be produced.