Systems, interactions and macrotheory

A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI

The pre-operative assessment of mitral-valve disease

No Abstract

Complete replacement of both mitral and aortic valves

No Abstract

Cardiac surgery for the cyanotic infant

No Abstrac

Detection of Vibrio cholerae O1 in animal stools collected in rural areas of the Limpopo Province

Vibrio cholerae (V. cholerae), the causative agent of cholera, has been responsible for various outbreaks worldwide and may be associated with animal faeces. In an attempt to understand the occurrence of this organism in the environment, 230 faecal samples were collected from pigs, chickens, goats, donkeys, cows and pigeons in rural areas of the Limpopo Province. Bacterial DNA was extracted from the faecal samples using a guanidium thiocyanate-based method. The DNA was screened for the presence of the sodB, rfb, FlaE, 16S rRNA and ctxA genes associated with V. cholerae, V. cholerae O1, V. cholerae O139 using 2 multiplex polymerase chain reactions (m-PCR). The V. cholerae sodB gene was detected in 74 of the 230 samples tested. Detection rates for the faecal samples obtained from individual species were as follows: cows (55/74), chickens (8/74), goats (2/74), donkeys (4/74), pigs (3/74) and pigeons (2/74). V. cholerae O1 was detected in (17/74) cow and (3/74) chicken samples, of which (9/17) cow samples and (3/3) chicken samples tested positive for toxigenic V. cholerae O1. The presence of this organism in faecal samples, taken close to water sources used by the villagers, raises the possibility that the causative V. cholerae O1 strain of the most recent outbreak in South Africa was present in the area 6 months prior to the outbreak.Keywords: Vibrio cholerae, PCR, animal faeces, cholera toxi

Syphilitic coronary ostial occlusion

No Abstract

Redress for Consumers in Terms of the Consumer Protection Act 68 of 2008: a Comparative Discussion

The Consumer Protection Act 68 of 2008Â is a groundbreaking piece of legislation in the realm of not only South African consumer law but also the South African law of contract. What is more, the Act also has worldwide implications as foreign companies selling goods and services in South African consumer markets will have to comply with the new legislation. In Part 1 of this paper, the avenues of redress available to the consumer in terms of the Act and the possible practical problems pertaining thereto are discussed. Part 2 deals with redress for consumers in terms of the European Union and relevant aspects of redress in the Spanish legal system. Part 3 is a comparative conclusion with regards to redress issues for consumers generally

The use of implantable cardiac pacemakers in the treatment of complete heart block

No Abstract

Biochemical reference values in elderly black subjects

Biochemical reference values for the black age group of ≥ 65 years were determined from the black urban population of the Orange Free State. Biochemical investigations performed were those included in the Sequential Multiple Analyser Computer profile because it includes the 20 most requested clinical chemistry investigations. Most of the reference values corresponded to values for the same age groups in the Western world. There was no age-related rise in the alkaline phosphatase values, which suggested absence of occult Paget's disease. Reference values for serum total protein and globulin were found to be higher than values derived from elderly white groups