How optimal life history changes with the community size-spectrum

This paper derives optimal life histories for fishes or other animals in relation to the size spectrum of the ecological community in which they are both predators and prey. Assuming log-linear size-spectra and well known scaling laws for feeding and mortality, we first construct the energetics of the individual. From these we find, using dynamic programming, the optimal allocation of energy between growth and reproduction as well as the trade-off between offspring size and numbers. Optimal strategies were found to be strongly dependent on size spectrum slope. For steep size spectra (numbers declining rapidly with size), determinate growth was optimal and allocation to somatic growth increased rapidly with increasing slope. However, restricting reproduction to a fixed mating season changed optimal allocations to give indeterminate growth approximating a von Bertalanffy trajectory. The optimal offspring size was as small as possible given other restrictions such as newborn starvation mortality. For shallow size spectra, finite optimal maturity size required a decline in fitness for large size or age. All the results are compared with observed size spectra of fish communities to show their consistency and relevance.

Researching the history of social work: Exposition of a history of the present approach.

This paper provides an exposition of Michel Foucault's 'history of the present' in order to make the case for its relevance to the study of social work history. It sets out the general principles underpinning this practice and considers its application to a particular research question relating to history of child welfare and protection social work in the Republic of Ireland. The paper seeks to highlight the challenges involved in its use and illuminate its potential value as an approach for researching the history of social work. It is concluded that this exposition offers one appropriate approach that could be employed within the growing field of social work history research across Europe.