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For economic transactions, including debt transactions, to occur in a market system, property rights are essential. The literature has focussed on finding empirical proof of the effect of property right regimes, noting differences between de jure and de facto property rights. We use a novel combination of data on wealth and demographics to investigate the effects of property right regimes on economic outcomes at the individual level. At the Cape, de jure property rights between freehold and loan farms differed. Historians, however, suggest that de facto property rights between these two property types were the same. We exploit the random variation of the birth order, specifically being the eldest son, to estimate whether the type of farm and therefore the type of property rights, mattered for economic activity, in our case, debt transactions. Our results suggest that historians were correct: loan farms were as secure in their de facto property rights, despite differences in de jure property rights. Our results confirm that the local context in which property right regimes are embedded is at least as important as the property right regime itself.

African economic history is experiencing a renaissance, and South African economic history likewise. Combining newly transcribed large historical datasets with econometric techniques now standard in the economics literature, economic historians have greatly improved our understanding of South Africa's development over the centuries. Yet many questions remain. This paper reviews the most recent contributions, several of which are published in this special issue, and surveys the road ahead.

The association between intake of fruits, vegetables, and legumes with cardiovascular disease and deaths has been investigated extensively in Europe, the USA, Japan, and China, but little or no data are available from the Middle East, South America, Africa, or south Asia.

The relationship between macronutrients and cardiovascular disease and mortality is controversial. Most available data are from European and North American populations where nutrition excess is more likely, so their applicability to other populations is unclear.

The relation between dietary nutrients and cardiovascular disease risk markers in many regions worldwide is unknown. In this study, we investigated the effect of dietary nutrients on blood lipids and blood pressure, two of the most important risk factors for cardiovascular disease, in low-income, middle-income, and high-income countries.

This research note identifies the period when South African prices began to move in unison with those of the country's lead trading partner. We find that South African wheat prices started reflecting UK trends soon after the discovery of diamonds and gold in the interior of the country. The mineral revolution, it seems, was responsible for integrating the broader South African economy - here proxied by agricultural prices - into the global economy. We further show that this integration was not confined to Cape Town; the coming of the railways ensured that markets in the larger Western and Eastern Cape and, importantly, the town of Kimberley, were well integrated with those in Cape Town. We therefore establish the start of South Africa's integration into the global market economy in the 1870s.

AbstractThe Minimum Requirements for Teacher Education Qualifications provides criteria for designing curricula for initial teacher education. This policy emphasizes that the roles that teachers have to fulfill should be interpreted as functions carried out by the collective of teachers in a specific school.The purpose of this research was to explore how effective student teachers are prepared to fulfil their multiple roles as teachers. A qualitative research design was employed by making use of focus group interviews. The findings indicate that teacher educators and teachers do not model the required roles of teachers and therefore fail to prepare student teachers adequately to fulfil these roles. The findings from the data will be discussed in this paper.

AbstractThis paper presents a descriptive study of an Early Childhood Development (ECD) intervention project, grounded in a community-research approach that resulted in more conducive ECD teaching and learning environments in township ECD centers in the Gauteng Province (Vaal Triangle) of South Africa. During the implementation phase of the project, grade R (the year before formal schooling) ECD practitioners from townships in the Vaal Triangle participated actively. Data was gathered through administering open-ended questionnaires and by conducting semi-structured interviews. Although the outcomes of this intervention varied, reflection from the researcher and the practitioners indicated that the project has started to address shortfalls in the teaching and learning environments of grade R ECD practitioners and as a result more conducive teaching and learning environments for learners in township ECD centers. This article discusses an ECD intervention project, focusing on innovative practices that impacted positively on the quality of the teaching and learning environments in township ECD centers in the Vaal Triangle. It also reports on improvements in the innovation skills and knowledge of the grade R ECD practitioners.

Flea infestations of pets continue to persist due to the lack of knowledge of flea biology and ecology. It is not unusual that pet owners believe regular hygiene, such as shampooing their dogs can replace regular insecticidal treatment. The objective of this study was to compare in a flea simulated environment, modelling exposure similar to that found in a home, that the use of regular physiological shampoo does not control fleas adequately when compared to a long acting topical formulation. Three groups of six dogs were formed: one untreated control group, one group treated monthly with the topical formulation of fipronil/(S)-methoprene, and a third group treated weekly with a hygiene shampoo. All dogs were infested with adult unfed Ctenocephalides felisfleas (200 ± 5) on Days -28 and -21. Each animal’s sleeping box was fitted with a plastic cup mounted to the inside roof of the box. The sleeping bench of each animal was covered with a carpet to accommodate flea development. The dogs were maintained in their kennels throughout the study. In order to maintain the environmental flea challenge, C. felispupae (100 ± 5) were placed in the plastic cup in each animal’s sleeping box on Days -14, -7, 0, 7, 14, 21, 28, 35 and 42. The dogs were combed and fleas counted weekly on Days -1, 3, 10, 17, 24, 31, 38, 45, and 51. The fleas were placed immediately back on the dogs. On Day 60, fleas were counted and removed. Flea infestations in the untreated control group at each count averaged between 46.2 and 74.2 fleas throughout the study. The average number of fleas infesting dogs was significantly different (p < 0.05) between the untreated and the two treatment groups and between the two treatment groups at all counts throughout the two months study (Days 3, 10, 17, 24, 31, 38, 45, 51 and 60). The efficacy was never below 99.1% in the fipronil/(S)-methoprene group, and efficacy in the shampoo group was never above 79.2%. Weekly shampooing in treatment group 3 was intentionally delayed after Day 42, to evaluate wether missing a weekly bath would affect the flea population. The Day 48 data indicate that forgetting or delaying a single weekly shampooing resulted in a clear increase in flea numbers and a significant decrease in efficacy from 68.2% to 34.8%. The fipronil(S)/methoprene treatment allowed a continuous control as demonstrated by the high efficacy against fleas, and also the number of flea-free dogs on seven of the nine weekly assessments, in spite of what was essentially a continuous flea challenge model.

AbstractWhile trade in African merchandise has lagged behind that of other developing countries, services exports – notably travel and tourism – have shown remarkable growth over the past decade. This paper calculates revealed comparative advantage for 147 countries using a new measure of the Balassa index. The results indicate that 29 of the 50 African countries in the dataset reveal a comparative advantage in travel service exports. The source of this comparative advantage lies in the natural and cultural resources of African countries, and the relative advantages of air versus sea transport – validating an augmented Heckscher-Ohlin hypothesis. If African countries are to benefit from the growth in world service exports, researchers and policymakers should note the (relative) potential for African travel service exports, especially in the smaller, landlocked destinations.

AbstractOral malodour may affect up to three billion people worldwide, with millions of dollars spent on treatment. Halitosis is often used synonymously, but oral malodour is the preferred term for any bad breath emanating from the mouth. Oral causes account for the majority of bad breath cases. It is the objective of this article to review the causes, classification and treatment of oral malodour for health care workers.

A two-equation model is presented which describes the conservation of heat in each phase of a porous medium in which diffusion is the predominant means of heat transfer, and of which the phases are not in thermal equilibrium with each other. The model is derived using the method of local volume averaging. This formulation, together with the introduction of characteristic temperature distributions, yields the definition of an effective and a coupled thermal conductivity tensor.

The formulism of a two-equation model for heat conduction in porous media, developed in a previous paper, is applied to the case of steady state one-dimensional heat transfer in a porous medium that is made up of geometrically similar units of similar size and of ordered spatial distribution. For this case study, the model-predicted locally volume-averaged temperature distributions for the solid and the fluid phase are compared to a numerical solution at a microscopic level, showing excellent agreement.

The techniques of transmission and scanning electron microscopy have found unique application in the study of the microstructure of surfaces. In this application, the use of gold and its alloys has proved indispensable in producing images of the required contrast and detail. A brief survey is given here of the origin of contrast in these techniques and of how gold can be used to improve the quality of electron microscope images.

Abstract: We have determined the prevalence of familial hypercholesterolaemia (FH) in a rural Afrikaner community by means of direct DNA screening for three founder-related Afrikaner low density lipoprotein (LDL) receptor gene mutations. A random sample of 1612 persons, aged 15–64 years, was selected as a subsample of 4583 subjects from an Afrikaner community living in the south-western Cape, South Africa. Participants who had a total serum cholesterol (TC) in the high TC category as defined in the consensus recommendations by the Southern African Heart Foundation, were screened for three founder-related LDL receptor gene mutations, causing FH in 90% of Afrikaners. Of the subsample, 201 participants (12.5%) had TC levels above the 80th percentile. In this group the combined prevalence of the three common Afrikaner LDL receptor gene defects (D206E, FH Afrikaner-1; V408M, FH Afrikaner-2; D154N, FH Afrikaner-3) was calculated as 1 : 83. When taking into account the reported background prevalence of other FH gene defects of 1 : 500 in this community, their overall prevalence of FH was estimated to be 1 : 72. The significant differences found between the FH patients and other high risk patients with raised cholesterol levels were higher TC and LDL cholesterol levels and lower high density lipoprotein cholesterol levels in FH patients. The treatment status of the molecularly identified FH patients and other hypercholesterolaemic persons suggests that this condition is inadequately diagnosed and poorly managed in this study population. An extrapolation to the entire South African population suggests that there are about 112 000 FH patients in the country who are underdiagnosed as a group and therefore not receiving the care that would help to reduce the burden of FH-associated ischaemic heart disease in South Africa.

The rationale behind this discussion is an attempt to apply the basic principles of thermodynamics to the operations of social systems. Since the second law of thermodynamics was critized by Maxwell and his colleagues, the notion of entropy was introduced as being similar to the idea of uncertainty. In this paper I will try to explain how uncertainty can be removed to a certain extent by information-flow through a system, provided that one should consider the flow of information as that which does logical work to the recipient's state of readiness and that evolution can only take place in systems which operate on a certain level of openness.

The aim of this research was to establish whether interferential currents (IFC) could significantly reduce the healing time for fractures of the tibia and thereby prevent nonunion. Males between the ages of 12 and 86, who had sustained fractures of the tibiae, were entered into this double blind clinical trial. According to strict inclusion and exclusion criteria, a final sample of 227 cases (208 subjects) were entered by block randomization into two groups; an experimental group (n=41) and placebo group (n=35). A further group was entered retrospectively – control group (n=151). IFCs were applied to the experimental group via suction electrodes for 30 minutes per day for 10 days, using a beat frequency of 10 – 25 Hz and a swing mode of 6 ∫ 6. The placebo group had only suction electrodes applied, the intermittent mode produced a rhythmical massage effect; subjects in this group commented on pain relief which resulted in the addition of the control group as a check on the possible effect of intermittent suction. The control group received no intervention. The data were analysed using analysis of covariance which resulted in a finding of no significant difference in the time taken to union for the three groups. This means that to date there is no reason to believe that IFCs (using the parameters of this trial) can reduce the healing time for new fractures of the tibia or prevent nonunion. However, further investigation is recommended. Copyright © 1997 Whurr Publishers Ltd.

After 4 years a coronary heart disease risk factor intervention programme produced equally large and significantly reduced risk profiles in two intervention towns compared with a control town. Intervention effects through community participation were assessed after cessation of the active intervention programme. The impact of secular trends was assessed in the control town and in two previously unstudied towns.

The flow stress distribution below the surface of previously deformed large copper single crystals is obtained when these are sliced into smaller component crystals. It is found that a considerable flow stress gradient extends for a distance of about 2 mm below the surface, measured along the slip direction. Electron microscope studies show that there is an increase in the cell size of dislocation structures near the surface and a decrease in dislocation density.On the basis of flow stress distribution measurements the stress-strain curves of single crystals of the same orientation but different sizes are shown to be consistent with the complete absence of a stage II in an infinitely large crystal. It is further shown experimentally that for very large crystals the value of τ111 is reduced considerably. This leads to the conclusion that τ111 should not be related to a fundamental physical phenomenon such as the stacking-fault energy of a metal.

Thin copper single crystals with a common axial orientation but with two different surface orientations are deformed in tension. The surface orientations were chosen so that in the one case the maximum glide path length of edge dislocations is reduced-fey thinning the specimen by electrolytic jet polishing of the surface while in the other the glide path length of screw dislocations is reduced. The extent of strain (ε11) in Stage I of the stress-strain curve is found to depend strongly on the glide path length of edge dislocations, while it depends only slightly on the glide path length of screw dislocations. Thin crystals with edge dislocation glide path lengths of about 50 microns can sustain the Stage I mode of deformation at applied stress levels three to four times that of crystals of normal thicknesses, while the rate of hardening (θ1) shows no systematic variation with thickness. It is concluded that the extent of strain in Stage I depends on the rate of accumulation of a primary dislocation array giving rise to an internal stress, while the rate of hardening depends on the rate of increase in the density of forest dislocations.

Deformed single crystals of copper are sectioned on the primary slip plane. The sections are studied by transmission electron microscopy and the natures of dislocation dipoles are determined on the basis of the kinematical theory of electron diffraction. It is found that both vacancy and interstitial dipoles are present. Dislocation configurations associated with open dipoles are analysed. It is suggested that open dipoles which originate at sessile long jogs in a particular screw dislocation are ended-off by glissile long jogs in the same screw dislocation to form closed dipoles.

The formation of elongated dislocation loops in deformed copper single crystals has been studied by transmission electron microscopy. A mechanism by which elongated loops could be formed is considered in detail. The density of these loops was found to increase only slightly during stage I of the stress-strain curve, but during the transition from stage I to stage II the density increased from about 5 × 1011 loops/cm3 to about 1013 loops/cm3. A model is proposed for work-hardening in the easy glide and transition regions, in which the dislocation loops indirectly act as obstacles to moving screw dislocations.

The removal of a surface envelope by chemical polishing of an unloaded crystal, previously deformed plastically in tension, is shown to reduce the unloading yield point. In addition it is shown that the yield point changes continuously with stress and a maximum effect is obtained at a given stress which depends on the crystal size. Furthermore the value of the maximum is a function of crystal size. On the basis of these results it is argued that the unloading yield point can probably be attributed to the non-uniform flow stress distribution which exists near the surface in deformed crystals.

The sub-surface region of a copper single crystal which had been strain hardened in tension to the end of stage II was studied by transmission electron microscopy. Sections bounded by the original surface as well as sections further below the surface were investigated. It was found that the sub-surface dislocation structure was in agreement with flow stress distribution curves which indicate the existence of a soft surface - hard core arrangement in strain-hardened crystals.

Burning mouth syndrome (BMS) is a chronic debilitating oral condition characterised by a burning sensation of the oral mucosa in an otherwise apparently normal person. Its aetiology and pathogenesis are obscure, but both psychogenic factors and peripheral and central neuropathies appear to be implicated. There is no cure for BMS, and treatment with either local or systemic medications focuses on the relief of symptoms and on improving quality of life. In recalcitrant cases, psychological/psychiatric intervention may be helpful. In order to improve treatment outcomes, a better understanding of the pathogenesis of this syndrome might provide a basis for the development of more effective management strategies. In this short review, we discuss current knowledge of the diagnosis, aetiopathogenesis, and management of BMS.

THREE different forms of filamentary silica have been discussed recently. Jaccodine and Kline1reported the growth of whiskers on the devitrified surface of vitreous silica which had been heated in a nitrogen stream for 24 hr. at 1,425° C. Abrahams and Stockbridge2showed that these growths were proper whiskers (Nabarro and Jackson3) of high-cristobalite with [111] as whisker axis. They also examined whiskers found on hydrothermally grown crystals of α-quartz4, and showed that these were α-quartz crystals elongated along [0001]. Haller5grew fibres of silica, non-crystalline and optically isotropic, on heated platinum surfaces (temperature about 1,100°C.) exposed to a mixture of silicon tetrafluoride and water vapour in a nitrogen stream.

To examine the drug utilisation patterns among hypertensive adults in a countrywide cross-sectional survey. The 1st South African National Demographic and Health Survey was conducted in 1998 on 13 827 persons aged 15 years and older. They were randomly selected, and stratified by province, urban and non-urban area. BP was measured electronically. Interviewers recorded demographic data, medical history and drug use patterns. The prevalence of hypertension in South Africans was 10.9% for men and 13.9% for women. Of hypertension men 41% and 67% of the women respectively knew about their hypertension. Of the women 55% and 39% of the men were taking medication, while 38% of women and 26% of men had controlled BPs below 160/95 mmHg. Of the hypertensive drugs used, diuretics were 41%, centrally acting antiadrenergic agents for 22%, ACE-inhibitors for 19% and Methyldopa for 15%. Differences were found in drug utilisation patterns of patients attending the public and private health care sectors. Of the hypertensive patients using drugs, 77% knew what condition was being treated and only 41% could name at least an appropriate drug for hypertension. Those who knew the name of the drugs taken, had better BP control than those who did not. The degree of hypertension diagnoses and control is inadequate and the South African health services need to address this. The drug utilisation pattern reveals prescribing patterns that are not in line with the nationally accepted guidelines for treating hypertension.

During an investigation of plastic deformation in controlled orientation single-crystals of copper, which were grown from the melt by the technique of Chalmers (1963), we have obtained direct evidence for wide stacking faults.