VIGS in afrika, met spesiale verwysing na Suid-Afrika

It is generally accepted that Africa is the continent that is most seriously affected by the AIDS epidemic. As a result of under-reporting, the actual incidence of AIDS may be more than ten times higher than indicated by the official figures. The majority of females of child-bearing age can be infected within the next 4-6 years. Infant mortality is expected to increase dramatically. Up to 50% of babies born to HIV-infected mothers are also infected. Most of these babies will develop an AIDS-related illness and die at a very young age. Twelve factors have been identified which place the black population of South-Africa among the highest risk groups in the world. No vaccine or cure is available at this stage. Education of the general population, with the aim to bring about a change in sexual practices, is the only way to prevent a demographic catastrophe in this country

A macroscopic kinetic model for DNA polymerase elongation and high-fidelity nucleotide election

The enzymatically catalyzed template-directed extension of ssDNA/primer complex is an impor-tant reaction of extraordinary complexity. The DNA polymerase does not merely facilitate the insertion of dNMP, but it also performs rapid screening of substrates to ensure a high degree of fidelity. Several kinetic studies have determined rate constants and equilibrium constants for the elementary steps that make up the overall pathway. The information is used to develop a macro-scopic kinetic model, using an approach described by Ninio [Ninio J., 1987. Alternative to the steady-state method: derivation of reaction rates from first-passage times and pathway probabili-ties. Proc. Natl. Acad. Sci. U.S.A. 84, 663–667]. The principle idea of the Ninio approach is to track a single template/primer complex over time and to identify the expected behavior. The average time to insert a single nucleotide is a weighted sum of several terms, in-cluding the actual time to insert a nucleotide plus delays due to polymerase detachment from ei-ther the ternary (template-primer-polymerase) or quaternary (+nucleotide) complexes and time delays associated with the identification and ultimate rejection of an incorrect nucleotide from the binding site. The passage times of all events and their probability of occurrence are ex-pressed in terms of the rate constants of the elementary steps of the reaction pathway. The model accounts for variations in the average insertion time with different nucleotides as well as the in-fluence of G+C content of the sequence in the vicinity of the insertion site. Furthermore the model provides estimates of error frequencies. If nucleotide extension is recognized as a compe-tition between successful insertions and time delaying events, it can be described as a binomial process with a probability distribution. The distribution gives the probability to extend a primer/template complex with a certain number of base pairs and in general it maps annealed complexes into extension products

The central noradrenergic system: an overview

The central noradrenergic system belongs to a group of brainstem neuromodulatory systems previously referred to as the ascending reticular activating system. In this article a heuristic model is presented of the central noradrenergic system depicting the major projections to other cerebral areas, its interactions with other neuromodulatory systems, mechanisms through which it can influence cerebral function, as well as the major functions and disorders associated with alterations in central noradrenergic activity. It is not the aim of this paper to provide fine detail on the various aspects, but rather to provide a concise overview where structure and function, as well as the interactions with other systems are brought together. The contents of the paper are summarized in a diagram. Keywords: Central noradrenergic system; Neuromodulatory; Brainstem African Journal of Psychiatry Vol. 10 (3) 2007: pp. 135-14

Resource Use Efficiency of Millet/Cowpea Intercropping in Niger State, Nigeria

The study examined the profitability and resources-use efficiency of millet/cowpea mixed farmers production in Niger state Nigeria. The primary data for the study was obtained using structured questionnaire administered to 80 randomly sampled farmers in Kotangora Local Government Area of Niger State. Farm budgeting technique and exponential production function were used to analyze the data. The results showed that the estimated gross margin, net farm income, gross ratio, operating ratio and returns on investment are N57,542.42 per hectare, N54,240.40 per hectare, 0.37, 0.31 and 2.15. The regression result shows that seed and family labour were statistically significant at 1% level of probability, while farm size and hired labour were statistically significant at 5% level of probability. The allocative efficiency results show that seeds, family labour and agrochemicals were under-utilized. Farm size and hired labour were over-utilized. Efficiency and productivity could be improved if the farmers use more seed, family labour, agrochemicals, less of hired labour and land.Crop Production/Industries,

Moisture preferences, growth and reproduction of the African nightcrawler, Eudrilus eugeniae (Oligochaeta)

As part of a comprehensive study of the biology of the economically important earthworm species Eudrilus eugeniae, the water relations of this species were studied. Moisture preferences were studied with the aid of cylindrical moisture towers filled with cattle manure. The cattle manure was dried, ground to a particle size of 500> <1000 (im and moistened. A moisture gradient was allowed to develop in the towers, the worms were added and the towers kept in an environmental control chamber at a temperature of 25°C and a relative humidity of 80%. The moisture preferences of both juvenile and adult worms were studied. The clitellate worms showed a wider preference range than the juveniles and the preference range of the juveniles coincided with the moisture levels at which cocoons were deposited. The highest frequency of occurrence for clitellate worms was between moisture levels of 80 and 82%. For cocoon deposition the highest frequency was at moisture levels between 79 and 80,5% and most juvenile worms showed a preference for a moisture range between 77,5 and 79%. The cocoons produced were incubated and the number of hatchlings per cocoon noted. The biggest number of offspring per cocoon hatched from cocoons originating from the moisture range of 79 to 80,5% coinciding with the highest frequency of cocoon deposition. From the results it appears that this earthworm species could be utilized in organic waste material with a relatively high moisture content

Life-cycle of the African nightcrawler, Eudrilus eugeniae (Oligochaeta)

In order to determine the potential of the earthworm Eudrilus eugeniae as waste processor and protein producer, the life history of this species was studied. The development, growth and reproduction of E. eugeniae were studied. Cattle dung was used as substrate with a moisture content of 70–80% and a temperature of 25°C. Data were gathered over a period of 300 days. It was found that cocoon production started within 24 h after copulation and can be sustained for at least 300 days. Cocoons are produced at an average rate of 1,65 cocoons per worm per day. The mean incubation period of cocoons is 16,6 days with a hatching success of 84% and 2,7 hatchlings per cocoon that hatched. Sexual maturity is attained by the offspring within 40 to 50 days after hatching. E. eugeniae is compared to other vermicomposting species

Cytogenetical studies of three Vitis species

The aim of this study was to determine the genomic relationship between Vitis vinifera, V. rotundifolia and V. rupestris. The hybrid between V. vinifera and V. rotundifolia (RT88-2) was almost sterile, whereas the hybrid between V. vinifera and V. rupestris (RP88-14) was fertile. A low percentage (0.52%) of the F1 hybrid (RT88-2) seed germinated, provided that V. vinifera was the seed parent. The result of this one way ability to cross could possibly be attributed to the incompatibility between the cytoplasm of V. rotundifolia and the chromosomes of V. vinifera. The F1 hybrid RT88-2 had 39 chromosomes of which 19 were derived from V. vinifera and 20 from V. rotundifolia. The homology differs between the genomes of V. vinifera and V. rotundifolia. The sterility of the F1 hybrid was chromosomal and was reflected in the abnormal meiosis and lower chiasma frequency. The F1 hybrid RP88-14 had normal meiosis and a chiasma, frequency similar to that of the parents. This could be attributed to the fact that the parents (V. vinifera and V. rupestris) have the same chromosome number and are closely related

Understanding the role that Quality of Work Life of food and beverage employees plays in perceived service delivery and productivity

3The purpose of this article is to determine the role that Quality ofWork Life plays in the perceived service delivery and productivityof food and beverage employees in Potchefstroom, South Africa.The questionnaires were distributed at selected food and beverageestablishments, and a total of 224 questionnaires were included in thestatistical analysis. The data analysis consisted of a demographic profile,a factor analysis and a structural equation model. The results indicatedthat job, creativity and aesthetics, actualisation, organisational supportand employee commitment attributes each exert an influence on theperceived service delivery and productivity of employees. This impliesthat food and beverage managers should try to improve the workingconditions of employees as well as provide an appropriate level ofrecognition to hardworking employees. Management should considerthe recommendations that are made in terms of the job satisfactionlevels of food and beverage service employees, as they are able topositively influence organisational performance and success.Key words: employee management, food and beverage sector, structural equation model,Quality of Work Lif

The neurobiological basis of fear: a concise review

No Abstract.South African Psychiatry Review Vol. 10 (2) 2007: pp.71-7

The role of neuroleadership in work engagement

Abstract: Orientation: Research communicated in this article contributes to the fields of neuroleadership and work engagement, and explores the use of Integral Theory’s All Quadrants All Lines (AQAL) four-quadrant model. It also applies the General Method of Theory-Building research in applied disciplines. Research purpose: The aim of this article is to determine the role that neuroleadership plays in improving work engagement. Motivation for the study: Human resource development lacks focus in theoretical research because of a lack of clarity of the connections between research and practice and a lack of interest in abstract theoretical issues (Storberg-Walker, 2006). Recent technological advances providing an insight into the biological and physiological bases of social interaction have presented new information on being engaged at work..