Demand for livestock tick control service in the Venda region, Northern Province

This article analyses factors influencing farmers’ willingness-to-pay for dipping services, as well as the revealed preference for dipping frequency using the multivariate and the logistic regression models. The study is based on a cross sectional survey of 125 smallscale cattle farmers interviewed in the Venda region of the Northern Province. Empirical multivariate and the logistic regression analysis show that liquidity, human resource, satisfaction with the programme and structure of production significantly influences farmers’ willingness-to-pay. However, the most important factor influencing both the willingness-to-pay and the dipping frequency is liquidity (employment). The results of this study have important implications for the delivery of veterinary services particularly in developing regions.Livestock Production/Industries,

Cost of breast preservation surgery for cancer

CITATION: Smit, B. J., Liebenberg, T. J. & Du Toit, D. F. 1992. Cost of breast preservation surgery for cancer. South African Medical Journal, 82:481.The original publication is available at http://www.samj.org.za[No abstract available]Publisher’s versio

PROBLEMS IN THE OPERATION OF LARGE CRYOGENIC SYSTEMS

Two liquid-hydrogen test facilities were operated for fourteen months. These cells have the capability for transfer of liquid hydrogen at flow rates up to 100 lbs/sec and have a total storage capacity for liquid hydrogen of 156,000 gallons. A number of design and operational problems were met, for example, stresses in 8-in. diameter transfer lines, times and quantities of liquid hydrogen required for cooldown of transfer lines, dewar instrumentation, gas requirements for pressurization of liquid hydrogen filled dewars, and techniques for warmup of large cryogenic dewars. Solutions to many of these problems are described and outstanding problems discussed on the basis of current observations. In addition, some techniques are described that are employed for safe operation of the liquid hydrogen facility, including helium block systems for leaky valves, room inerting to prevent fire or explosion in the event of a hydrogen leak, and the purity control of dewar pressurizing gases and the purity control of purges of gas and liquld hydrogen transfer lines. A summary is included of major modifications that are planned or underway for these test facilities. (auth

Compounded laxative formulations for substituting phenolphthalein with sennosides A & B in solid dosage forms

Purpose: Following the discovery of the carcinogenicity of phenolphthalein and the subsequent ban of this compound in several countries this study was undertaken to develop compounded formulations of laxative products containing the stimulant laxatives sennosides A and B. Methods: DSC and HPLC analysis was used to determine the compatibility of sennosides with commonly used excipients before compounding capsules, tablets and effervescent tablets containing sennosides A & B. The physical and chemical stability and release properties of these dosage forms were determined for 12 weeks at increased temperature and relative humidity. Results: Sennosides A & B were compatible with a wide variety of powdered excipients. However, these were incompatible with propyl paraben, sodium carbonate, stearic acid, citric acid, PEG, and sugar derivatives such as lactose, glucose and sorbitol when granulated with water. Not withstanding these interactions, it was possible to compound simple capsule, tablet and even an effervescent tablet formulations containing sennosides A & B that complied with pharmacopeial specifications. However, all these formulations were sensitive to moisture because when stored at increased temperature and relative humidity, disintegration times increased and dissolution rates decreased. Conclusion: Based on compatibility and stability studies simple, stable and elegant solid dosage forms containing sennosides A & B were compounded that can be used to replace phenolphthalein in a variety of solid dosage forms. Keywords: Compounding; Sennosides A & B; Phenolphthalein replacement; Drug-Excipient Compatibility > Tropical Journal of Pharmaceutical Research Vol. 3 (1) 2004: pp. 265-27

Estimating and attributing benefits from wheat varietal innovations in South African agriculture

It is well accepted that biological innovations, particularly varietal improvements, have greatly contributed to agricultural yield and output growth in the past. At the same time, public funding for breeding programmes such as at the Agricultural Research Council in South Africa has dwindled. In an effort to confirm the importance of continued funding of varietal improvement programmes, this paper estimates the benefits from wheat varietal innovations and attributes them to the different institutional sources (public, private and others) that have contributed to varietal changes in South Africa. The empirical analyses used data on market shares of wheat varieties planted by farmers and annual quantities of wheat produced across different wheat-production areas in South Africa (summer dryland, dryland winter, and irrigation). A vintage regression model was estimated to calculate the proportional yield gain from wheat varietal improvements. The results indicated that the rate of gain in yield as a result of releases of new wheat varieties (variety research) was 0.8 per cent per year (equivalent to 19.84 kg/ha/year) for dryland summer varieties, and 0.5 per cent for both irrigation (equivalent to 32.20 kg/ha/year) and dryland winter varieties (equivalent to 16.65 kg/ha/year). The attribution of benefits among different institutional sources confirms that not accounting for attribution of benefits by source and time period results is overestimation of benefits to any specific research programme. Attribution of benefits by institutional source showed that Sensako dominated, while the share of the ARC-SGI substantially declined, after deregulation of the wheat sub-sector. The results highlight the impact of the decline in public funding for wheat variety improvement research after deregulation and provide a strong argument for continued public funding for variety improvement in South Africa.http://www.tandfonline.com/loi/ragr202020-04-04hj2019Agricultural Economics, Extension and Rural Developmen

The evolving landscape of plant breeders’ rights : regarding wheat varieties in South Africa

Addressing the multiple challenges facing global agriculture requires integrated innovation in areas such as seeds, biotechnology, crop protection, grain storage and transport. Innovations related to plant improvement and the development of new or improved plant varieties will only happen at an optimal level if plant breeders’ rights (PBR) are properly protected. The objective was to analyse the evolving landscape of wheat plant breeders’ rights to address the dearth of empirical evidence of the patterns and trends of wheat varietal improvements in South Africa. We compiled a detailed and novel count and attribute database of wheat varietal innovations in South Africa from 1979 to 2013 using various sources. This data set was then analysed to ascertain the main trends in, and ownership of PBRs for wheat varietal improvements in South Africa over this period. A total of 134 PBR wheat varietal innovations were lodged from 1979 to 2013, an average of 6 applications per year. The administrative delays in granting PBR applications were substantially reduced by 77 days during the post-deregulation period (after 1996), indicating increased efficiency. The main PBR applicants were Sensako (39%), the Agricultural Research Council Small Grains Institute (ARC-SGI) (25%) and Pannar (15%). The ARC-SGI contributed to some of the PBRs owned by private companies through shared genetic resources before Plant Variety Protection (PVP) was implemented. Future innovations and dissemination of wheat innovations can be stimulated by plant variety protection, together with broader variety sector legislation that encourages both public and private sector investment.The paper is part of the PhD research by Charity R. Nhemachena on: ‘Biological innovations in South African agriculture: A study of wheat varietal change, 1950–2013’.The Bill and Melinda Gates Foundation grant to the University of Pretoria’s Department of Agricultural Economics, Extension and Rural Development.http://www.sajs.co.zaam2016Agricultural Economics, Extension and Rural Developmen

Does research and development (R&D) investment lead to economic growth? Evidence from the South African peach and nectarine industry

Agricultural research programmes in Africa have experienced waning state financial allocations. Efforts to change these funding trends have been fettered by the limited evidence of research investment benefits and the long lags associated with these returns. In a bid to provide such information, this article seeks to calculate the benefits of investments in the Agricultural Research Council’s peach and nectarine research programme – one of Africa’s successful and oldest research programmes. It uses the supply response function to model South Africa’s peach and nectarine industry and estimates the effect of deciduous fruit prices, production costs, research investment and weather on production. A lag distribution of research and development (R&D) investment is estimated using the polynomial distribution function and the derived elasticities are used to calculate the marginal internal rate of return. The study’s results reveal that investment in the peach and nectarine programme is associated with a marginal internal rate of return of 55.9%. This means that every R100 invested yields a R55.9 increase in value in the peach and nectarine industry. In light of these findings, it is concluded that R&D investment is worthwhile and recommends that the funding allocated to this programme be increased.The Agricultural Research Councilhttp://www.tandfonline.com/loi/rajs202019-12-06hj2018Agricultural Economics, Extension and Rural Developmen

Additive opportunistic capture explains group hunting benefits in African wild dogs

African wild dogs (Lycaon pictus) are described as highly collaborative endurance pursuit hunters based on observations derived primarily from the grass plains of East Africa. However, the remaining population of this endangered species mainly occupies mixed woodland savannah where hunting strategies appear to differ from those previously described. We used high-resolution GPS and inertial technology to record fine-scale movement of all members of a single pack of six adult African wild dogs in northern Botswana. The dogs used multiple short-distance hunting attempts with a low individual kill rate (15.5%), but high group feeding rate due to the sharing of prey. Use of high-level cooperative chase strategies (coordination and collaboration) was not recorded. In the mixed woodland habitats typical of their current range, simultaneous, opportunistic, short-distance chasing by dogs pursuing multiple prey (rather than long collaborative pursuits of single prey by multiple individuals) could be the key to their relative success in these habitats

Three new species of ciliated protozoa from the hindgut of both white and black wild African rhinoceroses

This report deals with the effect of the mode of feeding of the hindgut-fermenting herbivorous rhinoceros on the species of Protozoa fermenting the ingesta, as demonstrated by the proposed three new species of ciliated Protozoa: Didesmis synciliata differing from D. ovalis in having syncilia in place of simple cilia, Blepharoconus dicerotos being twice the size of B. cervicalis, and Blepharosphaera ceratotherii being one third the size of B. intestinalis. The findings are in line with the biological tenet that in herbivores the composition of the diet is the major factor determining the composition of the digestive organisms.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Chronic desipramine prevents acute stress-induced reorganization of medial prefrontal cortex architecture by blocking glutamate vesicle accumulation and excitatory synapse increase

While a clear negative influence of chronic exposure to stressful experiences has been repeatedly demonstrated, the outcome of acute stress on key brain regions has only just started to be elucidated. Although it has been proposed that acute stress may produce enhancement of brain plasticity and that antidepressants may prevent such changes, we still lack ultrastructural evidence that acute stress-induced changes in neurotransmitter physiology are coupled with structural synaptic modifications. Rats were pretreated chronically (14 days) with desipramine (DMI; 10 mg/kg) and then subjected to acute foot-shock (FS)-stress. By means of serial section electron microscopy, the structural remodeling of medial prefrontal cortex (mPFC) glutamate synapses was assessed soon after acute stressor cessation and stress hormone levels were measured. FS-stress induced a remarkable increase in the number of docked vesicles and small excitatory synapses, partially and strongly prevented by DMI pretreatment, respectively. Acute stress-induced corticosterone elevation was not affected by drug treatment. Since DMI pretreatment prevented the stress-induced structural plasticity but not the hormone level increase, we hypothesize that the preventing action of DMI is located on pathways downstream of this process and/or other pathways. Moreover, because enhancement of glutamate system remodeling may contribute to overexcitation dysfunctions, this aspect could represent a crucial component in the pathophysiology of stress-related disorders