Body weight and growth rate of South African Angora goat kids under different pre- and post-weaning management systems

The data used for this study were collected on 16 644 kids born between 2000 and 2004 in 12 different Angora goat studs representing different management systems. Body weight and growth rate of kids from birth to 16 months of age, as well the 18- and 21-month body weights and first kidding performance of ewe kids were evaluated. Variable growth rates were recorded among kids in the different studs, which can be ascribed largely to different environments and supplementary feeding practices. The pre-weaning growth performance of both ram and ewe kids was satisfactory. However, the same did not apply for post-weaning growth rates. In those flocks where kids did not receive any supplementary feeding after weaning, their body weights remained virtually constant from weaning up to eight months of age. This phenomenon where especially ewe kids did not grow well after weaning, needs to be investigated further, since it influences the reproductive ability of young ewes directly. This was evident from the poor reproductive performance of young ewes in some of the studs. On the other hand, the effect of different pre-weaning treatments did not seem to be carried over to body weight and reproductive performance at first kidding age. South African Journal of Animal Science Vol. 37 (2) 2007: pp. 132-14

Modulation of heat shock factors accompanies salicylic acid-mediated potentiation of Hsp70 in tomato seedlings

In plants, salicylic acid (SA) is a signalling molecule regulating disease resistance responses such as systemic acquired resistance (SAR) and the hypersensitive response (HR), and has been implicated in both basal and acquired thermotolerance. It has been shown that SA enhances heat-induced Hsp/Hsc70 accumulation in plants. To investigate the mechanism of how SA influences the heat shock response (HSR) in plants, tomato seedlings were treated with SA alone, heat shock, or a combination of both before analyses of hsp70 mRNA, heat shock factor (Hsf)–DNA binding, and gene expression of hsp70, hsfA1, hsfA2, and hsfB1. SA alone led to activation of Hsf–DNA binding, but not induction or transcription of hsp70 mRNA. SA had no significant effect on hsfA2 and hsfB1 gene expression, but potentiated the basal levels of hsfA1. In heat-shocked plants, Hsf–DNA binding was established, and increased hsfA1, hsfA2, and hsfB1 expression was followed by accumulation of Hsp70. SA plus heat shock showed enhanced Hsf–DNA binding, enhanced induction of hsp70 mRNA transcription, and gene expression of hsfA1, hsfA2, and hsfB1, resulting in potentiated levels of Hsp/Hsc70. Since increased hsp70 and hsf gene expression coincide with increased levels of Hsp70 accumulation, it is concluded that SA-mediated potentiation of Hsp70 is due to modulation of these Hsfs by SA. In our efforts to understand the role of Hsp70 in heat-related disease susceptibility, the degree of the complexity of the cross-talk between the pathways in which SA is involved, inter alia, the plant defence response, the HSR and thermotolerance, was further underscored

The series limited liability company: Innovative, flexible … and complicated

Since the introduction of the limited liability company (LLC) in the United States of America, various states have recognised the need to experiment with ways of improving the limited liability this structure offers. Of particular interest in this regard is the development of the series LLC. The series LLC was intended to provide a more flexible manner for businesses to conduct their activities, while preventing the risks of liability from affecting the entire LLC enterprise. However, uptake of the series LLC has been slow. This can allegedly be ascribed to uncertainty about how this structure may be utilised for commercial purposes, as its relation to business law remains, to a large extent, unresolved. This article examines these uncertainties, including the “separateness” of the series LLC, the recognition of the limited liability it affords, the application of bankruptcy law, taxation, as well as the fiduciary duties attached to the structure. Certain recommendations are made to ease the way forward, while further legal development is awaited. First, series LLC statutes need to specifically provide for all the rights of each series as well as the rights reserved for the master LLC. Secondly, these statutes must specify a default rule for the measure of “separateness” between the master LLC and each series. Finally, series statutes ought to provide for notice of the limited liability of each series to creditors of the LLC

Hierarchical Models for Independence Structures of Networks

We introduce a new family of network models, called hierarchical network models, that allow us to represent in an explicit manner the stochastic dependence among the dyads (random ties) of the network. In particular, each member of this family can be associated with a graphical model defining conditional independence clauses among the dyads of the network, called the dependency graph. Every network model with dyadic independence assumption can be generalized to construct members of this new family. Using this new framework, we generalize the Erd\"os-R\'enyi and beta-models to create hierarchical Erd\"os-R\'enyi and beta-models. We describe various methods for parameter estimation as well as simulation studies for models with sparse dependency graphs.Comment: 19 pages, 7 figure

Numerical modelling of an offshore pipeline laid from a barge

Bibliography: pages 81-85.This thesis addresses some of the issues involved in using numerical methods to simulate the laying of an offshore pipeline, the objective being to contribute to the expertise of the South African offshore technology. Of particular interest is the prediction of the stresses in the pipe during such an event. The thesis concentrates on the use and suitability of the finite element method to simulate the important aspects of the pipelaying problem. ABAQUS, a nonlinear general purpose finite element code, was chosen as numerical tool, and nonlinear effects such as geometry and drag, as well as contact and lift-off at the boundaries, are included in the models. The analysis is performed in two parts: in the static analysis the displaced equilibrium position of the pipeline under self weight, buoyancy and barge tension is sought, whilst the response due to wave action and barge motion is of interest in the dynamic analysis. Numerical experiments show the suitability of ABAQUS to model the behaviour of slender structures under both static loads and dynamic excitations

Occurrence of cyanobacteria genera in the Vaal Dam: implications for potable water production

The occurrence of cyanobacteria genera in the Vaal Dam was analysed and the factors that influence its dominance in the particular reservoir were also investigated. The study was motivated by the effects of the secondary metabolites of cyanobacteria genera on potable water production. Cyanobacteria genera have been found to be potentially toxic and capable of producing taste and odour secondary metabolites such as geosmin. Historical data from the Department of Water and Sanitation on percentage composition of cyanobacteria genera in the Vaal Dam, were collected for the 2006, 2007, 2011 and 2012 years. The concentrations of NO2-N and NO3-N and total phosphorus as well as water temperature data were collected from the same sampling point for the study period. This data, together with weather data, was statistically analysed for trends and relatedness between variables. It was found that Microcystis and Anabaena were the dominant cyanobacteria genera in Vaal Dam and they were jointly dominant over other phytoplankton genera during February and March. It was also found that the dominance of cyanobacteria genera significantly correlated with air and water temperature and concentration of NO2-N and NO3-N. It was concluded that the dominance of Microcystis and Anabaena genera among the cyanobacteria genera has significant implications for potable water production as the genera are associated with taste and odour metabolites and toxins. It was recommended that depth profiling be employed in order to identify an abstraction depth in the multilevel intake of the reservoir with relatively low levels of cyanobacteria cells. This would assist in minimising taste and odour events in potable water production.Keywords: Anabaena, cyanobacteria dominance, environmental conditions, Microcystis, Vaal Dam, water treatment

Osteosarcoma outcomes at a South African tertiary hospital

Background. Osteosarcoma is the most common primary malignant bone tumour. There is a high incidence of late presentation in the developing world, posing additional challenges in the treatment of this aggressive disease.Objective. To evaluate clinical outcomes of patients with osteosarcoma at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH), a tertiary hospital in South Africa, and compare these with similar studies in the developing world.Methods. This was a retrospective study of 61 patients treated at CMJAH between 2007 and 2011, with a minimum follow-up of 1.3 years (range 1.3 - 6.3).Results. An average of 4.5 months elapsed before patients were first seen at the CMJAH tumour unit. Fifty-eight patients (95.1%) initially sought conventional medical care. Three patients (4.9%) presented with pathological fractures. All the patients underwent biopsy, performed an average of 3 weeks after arrival at the tumour unit. In most cases the delay was due to limited access to magnetic resonance imaging. Most patients (n=41, 67.2%) were at Enneking stage 2B, 4 (6.6%) were at stage 2A and 16 (26.2%) were at stage 3. Of the patients, 13 (21.3%) underwent limb salvage procedures, 33 (54.1%) had amputations, 4 (6.6%) refused further treatment and 11 (18.0%) received palliative care only; 55 patients (90.2%) received chemotherapy. Two patients developed local recurrence, one of whom had an amputation and the other further wide excision. Two patients received palliative radiotherapy. Of the patients, 82.0% were HIV-negative, 4.9% HIVpositive and the rest of unknown status. At the time of the study, all but two patients, who came from other countries, were traceable or known to have died. Our overall 1-year and 5-year survival rates were 62.7% (95% confidence interval (CI) 49.1 - 73.9) and 38.1% (95% CI 24.6 - 51.4), respectively. Male patients and those with a higher Enneking stage had a poorer prognosis.Conclusion. Although most patients sought conventional medical care, unacceptable delays worsened survival. However, our survival rates are better than those in other developing countries. We advocate that professional, public and political awareness of osteosarcoma be improved as a matter of urgency, to facilitate rapid tertiary referral and expedite management

Using Monte Carlo simulation to quantify the cost impact of systemic risk factors in a project portfolio : a case study

CITATION: Joubert, F. J. & Snyman, M. 2021. Using Monte Carlo simulation to quantify the cost impact of systemic risk factors in a project portfolio : a case study. South African Journal of Industrial Engineering, 32(4):67-82, doi:10.7166/32-4-2518.The original publication is available at http://sajie.journals.ac.zaENGLISH ABSTRACT: In terms of project risk management, ‘systemic risk’ is identified as risks which are artefacts of the environment which a project is executed in, and are related to (i) the project team’s actions, (ii) how project controls are managed and interact, and (iii) how the project is planned and executed. This paper proposes a methodology to estimate the cost impact of systemic risk on a portfolio of projects by using risk quantification and Monte Carlo simulation, in the absence of a validated parametric risk model, to estimate the systemic risks in an entire portfolio of projects. The case study simulation results indicate a significant effect of systemic risks on the project portfolio risk profile, where systemic risks increased the P80 value of the contingency requirement by +85.6%. The successful management of systemic risk would contribute to project success by limiting unnecessary waste.AFRIKAANSE OPSOMMING: In terme van projekrisikobestuur word sistemiese risiko’s geïdentifiseer as risiko’s wat ʼn karakteristiek is van die omgewing waarbinne die projek uitgevoer word. Hierdie risiko’s hou verband met (i) die aksies van die projekbestuurspan, (ii) hoe projekkontroles bestuur word en ineenskakel, en (iii) hoe die projek beplan en uitgevoer word. Hierdie artikel stel ʼn metode voor wat gebruik kan word om die koste-impak van sistemiese risiko’s op ʼn projek portefeulje te bepaal waar daar ʼn gebrek is aan ʼn geldige paremetriese model vir die berekening van sistemiese risiko’s se impak op ʼn hele projekportefeulje. Dit word gedoen deur middel van risiko kwantifisering en Monte Carlo simulasie. Die resultaat toon ʼn noemenswaardige impak van sistemiese risiko’s op die risikoprofiel van die projekportefeulje, waar sistemiese risiko die gebeurlikheidsbegroting met +85.6 % verhoog het. Die suksesvolle bestuur van sistemiese risiko’s kan ʼn noemenswaardige effek op projek sukses uitoefen deur die beperking van onnodige vermorsing.http://sajie.journals.ac.za/pub/article/view/2518Publisher's versio

Testing the effectiveness of existing psycho-educational material (The Alliance Programme) for patients suffering from schizophrenia in the South African context

Objective:  Key Words:  Schizophrenia; Psycho-education; Participatory communication: comprehension.The objective of this study was to test the effectiveness of the existing psycho-educational material (The Alliance Programme) for patients suffering from schizophrenia in the South African context. Method: A qualitative research approach was used. Fifteen Setswana speaking participants, with a diagnosis of schizophrenia were exposed to the programme. Semi-structured and screening interviews were used to collect demographic and clinical data. The participants were divided into two groups and were exposed to either the Alliance Programme or on adapted version of the programme. Participatory communication instruments including focus groups, were used to assess comprehension and knowledge retention of the material over time. Results: Participants who were exposed to the original Alliance Programme experienced the contents of the programme to be technical, difficult to read or recall. They were unable to relate their previous symptoms to the psycho-education given. Participants who were exposed to the adapted version faired much better, gained more insight and were able to relate better to their illnesses. Participants preferred booklets with examples and illustrations, video clips and films over formal lectures. Conclusion: Psycho-education material given to people suffering from schizophrenia and their caregivers has to be adapted to their context to be effective