An analytical research into the price risk management of the soft commodities futures markets

Agriculture is of inestimable value to South Africa because it is a major source of job creation and plays a key role in earning foreign exchange. The most significant contribution of agriculture, and in particular maize, is its ability to provide food for the nation. For a number of decades government legislation determined prices, and as such the trade of grains on the futures exchange requires market participants to adapt to a volatile environment. The research focuses on the ability of market participants to effectively mitigate price volatility on the futures exchange through the use of derivative instruments, and the possibility of developing risk management strategies that will outperform the return offered by the market. The study shows that market participants are unable to use derivative instruments in such a way that price volatility is minimised. The findings of the study also indicate that the development of derivative risk management strategies could result in better returns than those offered by the market, mainly by exploiting trends on the futures market.Financial AccountingM. Comm. (Business Management

Contesting the efficient market hypothesis for the Chicago Board of Trade corn futures contract through the application of a derivative methodology

Corn production is scattered geographically over various continents, but most of it is grown in the United States. As such, the world price of corn futures contracts is largely dominated by North American corn prices as traded on the Chicago Board of Trade. In recent years, this market has been characterised by an increase in price volatility and magnitude of price movement as a result of decreasing stock levels. The development and implementation of an effective and successful derivative price risk management strategy based on the Chicago Board of Trade corn futures contract will therefore be of inestimable value to market stakeholders worldwide. The research focused on the efficient market hypothesis and the possibility of contesting this phenomenon through an application of a derivative price risk management methodology. The methodology is based on a combination of an analysis of market trends and technical oscillators with the objective of generating returns superior to that of a market benchmark. The study found that market participants are currently unable to exploit price movement in a manner which results in returns that contest the notion of efficient markets. The methodology proposed, however, does allow the user to consistently achieve returns superior to that of a predetermined market benchmark. The benchmark price for the purposes of this study was the average price offered by the market over the contract lifetime, and such, the efficient market hypothesis was successfully contested.Business ManagementD. Com. (Business Management

Cultivable microbiome of fresh white button mushrooms

Microbial dynamics on commercially grown white button mushrooms is of importance in terms of food safety assurance and quality control. The purpose of this study was to establish the microbial profile of fresh white button mushrooms, with the focus on potential presence of food-borne pathogens. The total microbial load was determined through standard viable counts. Presence and isolation of gram-negative bacteria including coagulase positive Staphylococci were performed using a selective enrichment approach. Dominant and presumptive organisms were confirmed using molecular methods. Total mushroom microbial counts ranged from 5.2 to 12.4 log cfu g-1, with the genus Pseudomonas being most frequently isolated (45.37% of all isolations). In total, 91 different microbial species were isolated and identified using Matrix assisted laser desorption ionisation time of flight mass spectrophotometry, PCR and sequencing. Considering current food safety guidelines in South Africa for ready-to-eat fresh produce, coliform counts exceeded the guidance specifications for fresh fruit and vegetables. Based on our research and similar studies, it is proposed that specifications for microbial loads on fresh, healthy mushrooms reflect a more natural microbiome at the pointof- harvest and point-of-sale.The National Research Foundation (NRF) and the Technology and Human Resources Industry Programme (THRIP), a partnership programme funded by the Department of Trade and Industry and managed by the NRF and the Department of Science and Technology-National Research Foundation funded Centre of Excellence in Food Security’s Food Safety Programme (Project 140701: Fresh Produce Safety).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1472-765X2018-02-28hb2017Plant Scienc

Comparison of safe alternative dipping treatments to maintain quality of zucchini

Decay and quality loss severely affect the marketability of fresh zucchini. Zucchinis are easily damaged during harvesting, - handling and - storage and no commercial treatment is currently available that can protect the fruit from desiccation, quality loss and decay. The aim of this study was to compare different environmentally friendly dipping treatments (CaCl2, Aloe vera, warm water, chitosan, ascorbic- and citric acid) to retain quality of fresh zucchini. Treated fruit were evaluated for physiological, sensory and microbiological parameters after storage for seven and 14 days at 5.8°C and 85% relative humidity. The CaCl2, Aloe vera and warm water treatments were the most effective in maintaining firmness and preventing an increase in the total microflora of the fruit. The outcome of this study shows that alternative control methods have potential for effective quality maintenance of fresh zucchini. Future studies should focus on alternative packaging materials in combination with these treatments.The Gauteng Department of Agriculture and Rural Development (GDARD)http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1745-45572017-04-30hb2017Food ScienceMicrobiology and Plant Patholog

Antibiotic resistance profiles of Staphylococcus spp. from white button mushrooms and handlers

The presence of Staphylococcus spp. has increasingly been reported in food products and poses a public health threat. The aim of this study was to determine the diversity of Staphylococcus spp. and the antibiotic resistance profiles of isolates obtained from freshly harvested and packed ready-to-eat mushrooms (n=432) and handlers’ hands (n=150). A total of 56 Staphylococcus isolates [46.4% (n=26) from hands and 53.6% (n=30) from mushrooms] were recovered belonging to 10 species. Staphylococcus succinus isolates (n=21) were the most prevalent, of which 52.4% came from mushrooms and 47.6% from hands. This was followed by S. equorum isolates [n=12; 91.7% (n=11) from mushrooms and 8.3% (n=1) from hands] and S. saprophyticus [n=9; 66.7% (n=6) from mushrooms and 33.3% (n=3) from hands]. Six isolates that were characterised as multidrug resistant were isolated from hands of handlers. Most (83.9%; n=47) of the 56 isolates were resistant to penicillin [53.2% (n=25) from mushrooms and 46.8% (n=22) from hands] and 14.3% (n=8) were resistant to cephalosporin classes [25% (n=2) from mushrooms and 75% (n=6) from hands], both of which are used to treat staphylococcal infections. Antibiotic resistance genes blaZ [25.0% (n=14) of all isolates of which 71.4% (n=10) were from hands and 28.57% (n=4) from mushrooms], tetL and tetK [both 1.8% (n=1) from hands], mecA [5.4% (n=3) from hands] and ermA [1.8% (n=1) from mushrooms] were detected from the 56 isolates. Only two (25.0%) of the eight methicillin-resistant staphylococci harboured the mecA gene, while only 11 (23%) of the 47 penicillin-resistant isolates harboured the blaZ gene [36.4% (n=4) from mushrooms and 63.6% (n=7) from hands]. Our results demonstrate that food handlers and harvested and packed ready-to-eat mushrooms could be a source of diverse Staphylococcus spp. that exhibit antimicrobial resistance. Clinically relevant S. aureus was only detected on one handler’s hand; however, the isolate was not multidrug resistant. The presence of diverse Staphylococcus spp. on mushrooms and the hands of handlers is a potential public health concern due to their potential to cause opportunistic infections

Tryptophan depletion in context of the inflammatory and general nutritional status of a low-income South African HIV-infected population

MV was the project leader. PB developed and validated the GC-MS method for the analysis of tryptophan and performed the biochemical and immunological analyses. MV and PB were responsible for the project design, analyses of the results and writing of the manuscript. PL was involved in the sourcing of patients and the clinical examination of all patients.The authors wish to thank the participants and staff of the Immunology Clinic at Kalafong Hospital and the South African National Blood Service at the Pretoria West satellite site.BACKGROUND : The essential amino acid tryptophan cannot be synthesised in the body and must be acquired through dietary intake. Oxidation of tryptophan, due to immune induction of the enzyme indoleamine 2,3- dioxygenase (IDO), is considered to be the main cause of tryptophan depletion in HIV infection and AIDS. We examined plasma tryptophan levels in a low-income sub-Saharan HIV-infected population and compared it to that of developed countries. Tryptophan levels were further examined in context of the general nutritional and inflammatory status. METHODS : This cross-sectional study included 105 HIV-positive patients recruited from the Kalafong Hospital in Pretoria, South Africa, and 60 HIV-negative controls. RESULTS : Patient tryptophan levels were in general markedly lower than those reported for developed countries. In contrast to reports from developed countries that showed tryptophan levels on average to be 18.8 % lower than their control values, tryptophan levels in our study were 44.1 % lower than our controls (24.4 ± 4.1 vs. 43.6 ± 11.9 μmol/l; p < 0.001). Tryptophan levels correlated with both CD4 counts (r = 0.341; p = 0.004) and with proinflammatory activity as indicated by neopterin levels (r = −0.399; p = 0.0001). Nutritional indicators such as albumin and haemoglobin correlated positively with tryptophan and negatively with the pro-inflammatory indicators neopterin, interleukin 6 and C-reactive protein. The most probable causes of the lower tryptophan levels seen in our population are food insecurity and higher levels of inflammatory activity. CONCLUSIONS : We contend that inflammation-induced tryptophan depletion forms part of a much wider effect of pro-inflammatory activity on the nutritional profile of HIV-infected patients.This research was supported by grant funding received from the Medical Research Council of South Africa and the South African Sugar Association (SASA Project 213).http://www.jhpn.net/index.php/jhpnam2016Internal MedicinePhysiologyPsychiatr

Estrogen-induced DNA synthesis in vascular endothelial cells is mediated by ROS signaling

<p>Abstract</p> <p>Background</p> <p>Since estrogen is known to increase vascular endothelial cell growth, elevated estrogen exposure from hormone replacement therapy or oral contraceptives has the potential to contribute in the development of abnormal proliferative vascular lesions and subsequent thickening of the vasculature. How estrogen may support or promote vascular lesions is not clear. We have examined in this study whether estrogen exposure to vascular endothelial cells increase the formation of reactive oxygen species (ROS), and estrogen-induced ROS is involved in the growth of endothelial cells.</p> <p>Methods</p> <p>The effect of estrogen on the production of intracellular oxidants and the role of estrogen-induced ROS on cell growth was studied in human umbilical vein endothelial cells. ROS were measured by monitoring the oxidation of 2'7'-dichlorofluorescin by spectrofluorometry. Endothelial cell growth was measured by a colorimetric immunoassay based on BrdU incorporation into DNA.</p> <p>Results</p> <p>Physiological concentrations of estrogen (367 fmol and 3.67 pmol) triggered a rapid 2-fold increase in intracellular oxidants in endothelial cells. E2-induced ROS formation was inhibited to basal levels by cotreatment with the mitochondrial inhibitor rotenone (2 μM) and xanthine oxidase inhibitor allopurinol (50 μM). Inhibitors of NAD(P)H oxidase, apocynin and DPI, did not block E2-induced ROS formation. Furthermore, the NOS inhibitor, L-NAME, did not prevent the increase in E2-induced ROS. These findings indicate both mitochondria and xanthine oxidase are the source of ROS in estrogen treated vascular endothelial cells. E2 treated cells showed a 2-fold induction of BrdU incorporation at 18 h which was not observed in cells exposed to vehicle alone. Cotreatment with ebselen (20 μM) and NAC (1 mM) inhibited E2-induced BrdU incorporation without affecting the basal levels of DNA synthesis. The observed inhibitory effect of NAC and ebselen on E2-induced DNA synthesis was also shown to be dose dependent.</p> <p>Conclusion</p> <p>We have shown that estrogen exposure stimulates the rapid production of intracellular ROS and they are involved in growth signaling of endothelial cells. It appears that the early estrogen signaling does not require estrogen receptor genomic signaling because we can inhibit estrogen-induced DNA synthesis by antioxidants. Findings of this study may further expand research defining the underlying mechanism of how estrogen may promote vascular lesions. It also provides important information for the design of new antioxidant-based drugs or new antioxidant gene therapy to protect the cardiovascular health of individuals sensitive to estrogen.</p