Effect of fertility control on a population's productivity

The effect of a sterilising agent upon the productivity of vertebrate pests, such as feral horses, feral dogs, wild rabbits or fruit-eating birds, depends upon the population's social structure and mating system. We investigated the theoretical effect on productivity of three forms of dominance, two effects of sterilisation on dominance, and four modes of transmission. Seventeen of the possible 24 combinations are feasible but lead to only four possible outcomes. Three of these result in lowered productivity. The fourth, where the breeding of a dominant female suppresses breeding in the sub-ordinate females of her group, leads to a perverse outcome. Productivity increases with sterilisation unless the proportion of females sterilised exceeds (n- 2)/(n- 1) where n (> 2) is the number of females in the group. A knowledge of social structure and mating system is therefore highly desirable before population control by suppressing female fertility is attempted or even contemplated

Development of a Diaphragm Stirling Cryocooler

Callaghan Innovation, formerly Industrial Research Ltd, has developed a novel free-piston Stirling cryocooler concept using metal diaphragms. The concept uses a pair of metal diaphragms to seal and suspend the displacer of a free-piston Stirling cryocooler. The diaphragms allow the displacer to move without rubbing or moving seals, thus resulting in a long-life mechanism. When coupled to a metal diaphragm pressure wave generator, the system produces a complete Stirling cryocooler with no rubbing parts in the working gas space. Initial modeling of this concept using the Sage modelling tool indicates the potential for a useful cryocooler. A proof-of-concept prototype was constructed and achieved cryogenic temperatures. CFD modeling of the heat transfer in the radial flow fields created by the diaphragms shows the possibility of utilizing the flat geometry for heat transfer, reducing the need for, and the size of, expensive heat exchangers. A second prototype has been designed and constructed using the experience gained from the first. Further CFD modeling has been used to understand the underlying fluid-dynamic and heat transfer mechanisms and refine the Sage1 model. The prototype produces 29 W of cooling at 77 K and reaches a no-load temperature of 56 K. This paper presents details of the development, modeling and testing of the second iteration prototype

Humanitarian, International Nursing and the New Zealand and Recipients of the Florence Nightingale Medal 1920-1999

The purpose of this study was to explore the history of the Florence Nightingale Medal and in particular its New Zealand recipients. New Zealand nurses have, over many years, contributed to international nursing by providing service during conflicts and disasters. Several have worked with the Red Cross and, of these nurses, twenty-two have been awarded its highest honour, the Florence Nightingale Medal. This thesis related the history of the Red Cross and Red Crescent Movement, and its place in humanitarian and international nursing. It traces New Zealand nursing's involvement in this, and offers a history of the New Zealand recipients of the Florence Nightingale Medal, 1920-1999. The personal and professional stories of five New Zealand nurses who were awarded the medal between 1969 and 1999 were gathered through oral history interviews. Their stories are used to consider in more detail the motivations and experiences of nurses who work in these circumstances, and the way in which humanitarian nursing practice and Red Cross principles shaped and challenged their practice. The thesis therefore documents the work of five New Zealand nurses who have demonstrated exceptional courage, dedication, and commitment to humanitarian causes and international nursing practice. As an exploratory and descriptive study which has drawn on both historical and contemporary sources of information, it raises awareness about the Red Cross and its nurses, humanitarian nursing practice in particular, and international nursing in general