Aspects of the feeding behaviour of intensively reared trout

Feeding behaviour of trained rainbow trout was investigated by the use of demand feeders, under different light conditions. The effects of the energy content of diet, and the size, colour and texture of feed pellets, on the feeding behaviour, were studied. An attempt was made to locate the assumed centres for feeding and satiety in the hypothalamus of brain by the intraperitoneal injections of goldthioglucose. Feeding under nine different constant photoperiods at 160 lux, at a temperature of 13.5°C, showed that trout exhibit a rhythmic pattern of feeding behaviour in all photoperiods except in continuous darkness.Feeding rhythms of trout attributable to the degree of gut distension were formed every eight to ten hours. Further studies by varying levels of light intensity revealed the interaction of light intensity and photoperiod. At shorter photoperiods lower levels of light intensity decreased the feeding activity in terms of food intake but by increasing the photoperiod the same feeding activity was accomplished as by the fish subject to a short photoperiod but under higher light intensity.Simulated effect of increasing and decreasing daylengths did not affect the overall food intake and growth performance. Trout are quite efficient in adjusting their food intake in terms of energy content. Colour, size and texture of feed pellets affect the feeding responses and elicit preferential food selection behaviour in trout. Goldthioglucose induced some reversable toxic effects upon general physiology of trout and did not produce any lesions in the assumed areas of feeding and satiety centres in the brain.  It was concluded that the feeding behaviour of trout exhibited selective preferences according to the physical nature of food items and those preferences could be further influenced by the biotic and abiotic factors, light being one of the most important abiotic factors.

A social psychological analysis of strikes

A participant observation method was employed :in the study of a 20-week stoppage at Ansells Brewery Limited, a constituent company of Allied Breweries (U.K.). The strike, :involving 1,000 workers, began :in opposition to the implementation of a four-day working week and culminated in the permanent closure of the brewery. The three main phases of the strike's development (i.e., its :initiation, maintenance and termination) were analysed according to a social-cognitive approach, based on the psychological imagery, beliefs, values and perceptions underlying the employees' behaviour. Previous psychological treatments of strikes have tended to ignore many of the aspects of social definition, planning and coordination that are an integral part of industrial action. The present study is, therefore, unique in concentrating on the thought processes by which striking workers .make sense of their current situation and collectively formulate an appropriate response. The Ansells strike provides an especially vivid illustration of the ways in which the seminal insights of a small number of individuals are developed, via processes of communication and:influence, into a consensual interpretation of reality. By adopting a historical perspective, it has been possible to demonstrate how contemporary definitions are shaped by the prior history of union-management relations, particularly with regard to: (a) the way that previous events were subjectively interpreted, and (b) the lessons that were learned on the basis of that experience. The present approach is psychological insofar as it deals with the cognitive elements of strike action. However, to the extent that it draws from relevant sections of the industrial relations, organizational behaviour, sociology, anthropology and linguistics literatures, it can claim to be truly interdisciplinary.

An evaluation of certain aspects of an occupational health service

This thesis has been concerned with obtaining evidence to explore the proposition that the provision of occupational health services as arranged at the present time represents a misallocation of resources. The research has been undertaken within the occupational health service of a large Midlands food factory. As the research progressed it became evident that questions were being raised about the nature and scope of occupational health as well as the contribution, in combating danger at work, that occupational health services can make to the health and safety team. These questions have been scrutinized in depth, as they are clearly important, and a resolution of the problem of the definition of occupational health has been proposed. I have taken the approach of attempting to identify specific objectives or benefits of occupational health activities so that it is possible to assess how far these objectives are being achieved. I have looked at three aspects of occupational health; audiometry, physiotherapy and pre-employment medical examinations as these activities embody crucial concepts which are common to all activities in an occupational health programme. A three category classification of occupational health activities is proposed such that the three activities provide examples within each category. These are called personnel therapy, personnel input screening and personnel throughput screening. I conclude that I have not shown audiometry to be cost-effective. My observations of the physiotherapy service lead me to support the suggestion that there is a decline in sickness absence rates due to physiotherapy in industry. With pre-employment medical examinations I have shown that the service is product safety oriented and that benefits are extremely difficult to identify. In regard to the three services studied, in the one factory investigated, and because of the immeasurability of certain activities, I find support for the proposition that the mix of occupational health services as provided at the present time represents a misallocation of resources.