Noncontingent positive and negative feedback during maximal exercise.

A closed skill, maximal effort on a bicycle ergometer was used to study the effects of noncontingent external feedback on performance, perceived effort, and the subject's assessment of the quality and accuracy of the feedback. The 47 subjects included elite athletes as well as physical education majors. They were asked to perform a series of 5 60-sec. trials of maximal effort, trials which included positive, negative, positive and negative, and no-feedback conditions. Although there were no significant effects on performance for the various feedback conditions, subjects judged the positive feedback favourably and as accurate, but negative feedback was judged unfavourably and considered to be inaccurate. This result is seen as supportive of the 1982 McCarrey, et al. supposition that successful athletes may have less need to internalize attributions of effect.     

Towards a Common Civilization

An address given on 3 April 1997 at the Institute of Islamic Understanding, Malaysia (IKIM) on the occasion of the official visit of H.E. Prof. Dr Roman Herzog, President of the Federal Republic of Germany     

Fine-grained Concurrency with Separation Logic

Reasoning about concurrent programs involves representing the information that concurrent processes manipulate disjoint portions of memory. In sophisticated applications, the division of memory between processes is not static. Through operations, processes can exchange the implied ownership of memory cells. In addition, processes can also share ownership of cells in a controlled fashion as long as they perform operations that do not interfere, e.g., they can concurrently read shared cells. Thus the traditional paradigm of distributed computing based on locations is replaced by a paradigm of concurrent computing which is more tightly based on program structure. Concurrent Separation Logic with Permissions, developed by O’Hearn, Bornat et al., is able to represent sophisticated transfer of ownership and permissions between processes. We demonstrate how these ideas can be used to reason about fine-grained concurrent programs which do not employ explicit synchronization operations to control interference but cooperatively manipulate memory cells so that interference is avoided. Reasoning about such programs is challenging and appropriate logical tools are necessary to carry out the reasoning in a reliable fashion. We argue that Concurrent Separation Logic with Permissions provides such tools. We illustrate the logical techniques by presenting the proof of a concurrent garbage collector originally studied by Dijkstra et al., and extended by Lamport to handle multiple user processes.     

Addiction treatment providers’ perceptions of publicly-funded treatment services in the Western Cape,South Africa

This study explored addiction treatment implementation effectiveness of publicly-funded services in the Western Cape, South Africa, as perceived by service providers. Informants were six service providers from state-subsidised and public outpatient treatment services for substance use disorders (SUDs) (social workers = 4, registered counsellor = 1, psychologist = 1). Data were collected using semi-structured interviews and analysed by means of thematic analysis. The three themes that emerged from the analysis pertained to addiction treatment providers’ perceptions of the effectiveness of treatment services, lack of aftercare services, and service access and participation. Findings highlight sites for interventions to enhance the provision of publicly-funded evidence-based treatment services for SUDs in South Africa; enabling recipients to yield the well-established benefits of treatment.