Developments in modelling of backward erosion piping

One of the failure mechanisms that can affect the safety of a dyke or another water-retaining structure is backward erosion piping, a phenomenon that results in the formation of shallow pipes at the interface of a sandyor silty foundation and a cohesive cover layer. Themodels available for predicting the critical head at which the pipe progresses to the upstreamside have been validated and adapted on the basis of experiments with two-dimensional (2D) configurations. However, the experimental base for backward erosion in three-dimensional (3D) configurations in which the flow concentrates towards one point, a situation that is commonly encountered in the field, is limited. This paper presents additional 3D configuration experiments at two scales with a range of sand types. The critical gradients, the formed pipes and the erosion mechanism were analysed for the available experiments, indicating that the erosion mechanism is more complex than previously assumed, as both erosion at the tip of the pipe (primary erosion) and in the pipe (secondary erosion) are relevant. In addition, a 3D configuration was found to result in significantly lower critical gradients than those predicted by an accepted calculation model calibrated on the basis of 2D experiments, a finding that is essential for the application of the model in the field

Stolen Generations: Online Testimonies as Sources of Social Justice: Towards an Ethics of Encounter

In this paper, I am using the provocation of `the source to examine the significance of a recent iteration of Stolen Generations testimonies to questions of contemporary social justice. This testimonial form has had a complicated and fraught history across Australian legal and cultural domains: in the handful of cases that have dealt with injuries arising out of the Stolen Generations, courts have placed oral testimony in contest with state documentary records1 ; oral testimony has also featured in different iterations of extra-legal Stolen Generations projects, which have been produced by state, corporate and Indigenous parties, sometimes leading to the problem of testimonies being co-opted into state and private projects, which do not necessarily benefit Indigenous peopl

The vegetation of the SA Lombard Nature Reserve and its utilisation by certain antelope

Zoologica Africana 1 (1): 55-7

Application of four dyes in gene expression analyses by microarrays

BACKGROUND: DNA microarrays are widely used in gene expression analyses. To increase throughput and minimize costs without reducing gene expression data obtained, we investigated whether four mRNA samples can be analyzed simultaneously by applying four different fluorescent dyes. RESULTS: Following tests for cross-talk of fluorescence signals, Alexa 488, Alexa 594, Cyanine 3 and Cyanine 5 were selected for hybridizations. For self-hybridizations, a single RNA sample was labelled with all dyes and hybridized on commercial cDNA arrays or on in-house spotted oligonucleotide arrays. Correlation coefficients for all combinations of dyes were above 0.9 on the cDNA array. On the oligonucleotide array they were above 0.8, except combinations with Alexa 488, which were approximately 0.5. Standard deviation of expression differences for replicate spots were similar on the cDNA array for all dye combinations, but on the oligonucleotide array combinations with Alexa 488 showed a higher variation. CONCLUSION: In conclusion, the four dyes can be used simultaneously for gene expression experiments on the tested cDNA array, but only three dyes can be used on the tested oligonucleotide array. This was confirmed by hybridizations of control with test samples, as all combinations returned similar numbers of differentially expressed genes with comparable effects on gene expression

Anxiety and the patient with breast cancer: a review of current research and practice

Breast cancer is one of the most common cancers worldwide. Statistics reveal that the number of women diagnosed with breast cancer is increasing in South Africa. In particular, there appears to be a growing incidence in younger, black women in urban areas. Family practitioners and oncology healthcare professionals are going to be treating an increasing population of patients with breast cancer. Research has shown that in many instances, the psychological needs of patients with breast cancer are not adequately addressed, and that often the physical crisis is seen as more immediate. Also, healthcare professionals and oncologists may not be aware of the prevalence of co-morbid psychological distress, and thus do not focus on this aspect of the diagnosis. As a result, women who experience psychological distress during and after treatment may not be referred for psychological management. This may have a significant impact on their quality of life during this period and may even affect their compliance with treatment. This ultimately has implications for their ongoing health and survival. This review of the available literature aims to heighten awareness of healthcare professionals to the current situation, with a view of improving the mental health care of South African patients with breast cancer.Keywords: anxiety, breast cancer, depression, adjuvant treatment, psycho-oncolog

Health outcomes in Bulgaria:Simulated effects of obesogenic environmental changes in adulthood versus childhood

Objective: Bulgarian government efforts to tackle obesity are focused mainly on guidelines affecting children. However, it is unclear whether targeting children for obesity-related health policies yields better long-term health outcomes as opposed to changing the risk of obesity in adulthood. This study aims to evaluate where policy efforts should be directed to alleviate the health burden associated with obesity. Methods: We compare the impact on population health of two simulated scenarios when (a) the prevalence of obesity upon entering adulthood is lowered; (b) the risk of getting an unhealthy weight as an adult is reduced. Additionally, we run (c) combinations of the two and (d) childhood obesity prevention on the one hand, and worsening (increasing) obesity incidence later in adulthood on the other. Results: Our findings show that obesogenic environmental changes throughout adulthood have a stronger effect on life expectancy (LE), diabetes-free life expectancy (DFLE) and type 2 diabetes prevalence outcomes compared to lowering the proportion of individuals with obesity during adolescence. Nevertheless, a sizable reduction in the number of young adults with unhealthy weight has the potential to recover years of LE/DFLE that would be lost if the risk of obesity in adulthood would continue to grow in time. Conclusions: The two types of policies' (a-b) effects are not equivalent in strength and the best way forward is dependent on future obesity incidence trends.</p

An assessment of selected organisational-based factors on the perceived success of agribusinesses: a corporate entrepreneurship perspective

The objective of this study was to investigate the influence of selected organisational-based factors on the perceived success of agribusinesses in South Africa. Business success, for the purposes of this study, was measured by means of two dependent variables, namely Business development and improvement and Business growth. Structured questionnaires were administered to the managers of five of the largest and three smaller agribusinesses in South Africa. A total of 533 usable questionnaires were returned. The construct validity of the measuring instrument was assessed by means of a principal component exploratory factor analysis and by calculating Cronbachs’s alpha coeffi cients. The results show that the managers in the participating agribusinesses perceived the selected organisational-based factors of Strategic intent, Autonomy, Customer orientation and Rewards to have a positive influence on their Business development and improvement. A positive relationship was also found to exist between the selected organisational-based factors of Strategic intent and Customer orientation and the dependent variable Business growth in the participating businesses. Practical recommendations were also proposed to enhance and foster corporate entrepreneurship within these businesses.Key words: corporate entrepreneurship, agribusinesses, perceived succes

ABC implementation in the Nelson Mandela Bay Metropole: How far should manufacturing organisations go?

Activity-based costing (ABC) success factors have been studied in past research, mostly by using commonly  known success factors. In this qualitative study, a literature review and interviews were used to establish what factors are responsible for the successful implementation of ABC. The number of semi-structured  interviews was limited to 13 ABC adopters in the Nelson Mandela Bay Metropole. The fi ndings suggested that ABC can be enhanced with the use of activity-based budgeting (ABB) and activity-based management (ABM). In addition, the use of ABC in conjunction with capital investment decisions may ensure that correct decisions are made when critical long-term projects are considered. Extensive identifi cation of cost drivers is benefi cial to the extent where the product loses its relationship with the overhead cost. It is evident from this research that considering fi xed indirect overheads in ABC is not always benefi cial for a manufacturing organisation  unless there is a clear link to the end-product.Key words: activity-based costing (ABC), budgeting, implementation, success factors, metropole, capital investments, competitio

Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies