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Evaluation of the CERES-Maize Model for the smallholder farming sector of Zimbabwe: model calibration
No full textThe Ceres-Maize model was calibrated using documented historical data from Domboshawa, an agricultural training centre about 30 km north of Harare, Zimbabwe. Agronomic data from long-term tillage trials conducted during the 1990/91 to 1995/96 cropping seasons were used. Theses data were, however, limited to silking, maturity dates and grain yields of the R215 maize variety. The initial genetic coefficients for variety R215 were obtained from previous local studies. Modified coefficients were obtained using the Genotype Coefficient Calculator from the model, based on the results from Domboshawa. In cases where the procedure predicted coefficient values outside the acceptable range, these were determined manually. Results from the model showed that silking and maturity dates were accurately predicted with R2 values of 0.97 and 0.88, respectively. Slopes of lines for both traits were not significantly different from 1 at the 1 % level (p ? 0.001 and p < 0.006, respectively). A highly significant relationship between measured and simulated grain yield was also observed (p ? 0.002; R223 = 0.93), indicating that the model can be used successfully to predict maize yields under similar conditions
A fuzzy controller based demand - side management system design for optimization of induction furnaces.
No full textFrom Conference Proceeding (714) Power and Energy Systems - 2011The paper is a design of an automated Demand-side management system that will optimize electricity usage in a manufacturing plant using induction furnaces, through a multi-furnace controller. The multi-furnace controller controls two furnaces which alternate in between being a melting and a holding furnace. The control system selectively delivers preselected percentages of available power to furnaces. The power supply delivers power to both furnaces. A capacitor station in parallel connection
to the power supply and the furnaces is tuned to form a tank circuit therewith and acts as the power factor correction device. Switches control the selected power delivered to the furnaces respectively and control the delivery of a first portion of the power for holding molten product in the hold furnace as the master control.
Simulation model was design using fuzzy logic controller.The results show that using the multi-furnace controller results in a 30% decrease in the operating costs of the
furnaces as demonstrated by the model plots
Assessing the impacts of conservation agriculture on farmer livelihoods in three selected communities in central Mozambique
No full textDoctoral ThesisAgriculture is the major source of livelihood for more than 80% of the people in
Mozambique. Many years of cropping using slash-and-burn practices has resulted in negative environmental impacts which result in low crop productivity, food insecurity, hunger and malnutrition. During the last 20 years there have been a number of initiatives by rural development and research organizations working in partnership with the government to
introduce environmentally friendly, more efficient and sustainable technologies, so as to restore soil fertility, improve moisture conservation and ensure increased crop productivity. Among these technologies, conservation agriculture has been promoted since 2007 by the International Centre for Tropical Agriculture (CIAT), the International Maize and Wheat Improvement Centre (CIMMYT) in collaboration with the Ministry of Agriculture (MINAG) in central Mozambique. Conservation Agriculture builds on three principles: minimal soil disturbance, permanent soil cover and crop rotation. This study assesses the alleged livelihoods benefits of conservation agriculture for smallholder farmers. These benefits include improving productivity, household income, food security and subsequently alleviating poverty. First, the benefits of conservation agriculture in
southern Africa as reported in the literature were reviewed. Then empirical data was collected in the communities of Nhanguo, Pumbuto and Ruaca in central provinces of Manica and Sofala in Mozambique. The data was used to assess the differences between 75 households
who had adopted (some) conservation agriculture techniques and 90 households who had not adopted any conservation agriculture techniques. Furthermore, how smallholder farmers are redesigning conservation agriculture was examined. Finally, the energy and labor efficiency of conservation agriculture was assessed. The results show that vulnerable livelihoods, lack of access to agricultural assets, lack of
institutions supporting smallholder farmers are among the factors explaining the slow
adoption of conservation agriculture in central Mozambique. Under these conditions
conservation agriculture has only a weak impact on livelihood outcomes, mostly through a slight improvement in crop productivity. Farmers are actively engaged in redesigning all the three principles of permanent soil cover, minimum tillage and crop rotation, thus indicating that promoting conservation agriculture as a package may not be suitable for all categories of smallholder farmers. Finally, comparing energy use within conservation agriculture and conventional agriculture shows some efficiency gains. The study concludes that conservation agriculture is a complex technology whose short- and long-term benefits are not fully apparent. If smallholder farmers are to adopt the technology, a participatory approach to
adapting the technology to their need might be more promising than the current transfer-oftechnology approach
Impact of vaccines of controlling typhoid fever in Kassana-Nankana district of upper east region of Ghana: insight from a mathematical model
No full textPartnerships in Education, Training and Management for Sustainable Natural Resources Processing in Zimbabwe?s Rural Communities
No full textIn the course of their everyday academic business, universities in developing countries turn over large volumes of mainly foreign-sourced knowledge, while on the other hand typical communities in rural areas are starved of vital information for their own survival and development. Partnerships between universities and their immediate communities have a potential to turn the fortunes of both parties in economic ways. In the area of natural resources harvesting for commercial purposes, the university-community partnership plays a critical role in fulfilling mutual needs and tackling environmental stability. This paper explores the perceived roles of education, training and management practices on encouraging rural communities to recognize natural resources within their environments and to develop appropriate capacity to sustainably exploit them for economic benefit. Elaborating on the views of selected players and with reference to textile materials sourcing and processing, the paper identifies the complementary functions of education, management and rural communities in developing informed appreciation for sustainable harvesting of natural resource
Vice Chancellor's Fifteenth Graduation Ceremony Speech
No full textAddress by Professor Lindela Rowland Ndlovu, Vice Chancellor at the Fifteenth Graduation Ceremony
A study to determine factors associated with domestic violence among concordant and discordant couples in Zimbabwe
No full textBackground: HIV/AIDS and domestic violence are two of the major health problems affecting the lives of millions of people worldwide. Many people have fallen victim to these two pandemics especially in sub-Saharan Africa and much of the developing countries.
Aim: In the present paper, we investigate factors associated with domestic violence amongst four couple groups namely: concordant negative, concordant positive, discordant male positive and discordant female positive.
Methods: Data from the Zimbabwe Demographic Health Survey (2005-2006) was used to run a Chi-square test to compare couples on demographic factors, economic factors and decision making. A logistic regression model which helps to control for confounding was fitted to identify factors associated with domestic violence for the different couple groupings.
Results: Domestic violence prevalence ranges from 39.4% to 53.5% for the four couple groupings, which is quite high requiring corrective measures. Concordant positive couples experienced the most domestic violence with 53.5% reporting that they experienced domestic violence and discordant female positive couples experienced the least domestic violence with 39.4% of them reporting that they experienced domestic violence. Among the factors associated with domestic violence, it was found that wealth has an inverse relationship with domestic violence, meaning the richer the couples the lesser the number of cases of domestic violence.
Conclusion: Higher household economic status was associated with less domestic violence in marriage and thus we recommend that communities engage in income generating projects as an indirect way of reducing domestic violence
Epidemiological consequences of non-compliance to HCV therapy among IDUS
No full textTreatment for infections with hepatitis C viruses has recently developed markedly, and range from nonspecific interferon-based treatments to specific antiviral treatments, such as those that inhibit hepatitis virus coded protein production or activity. Despite advancements in the management of HCV, the epidemic prevalence continues to rise among injection drug misusers who, are responsible for approximately 90% of new HCV cases, because of their poor compliance with treatment requirements and conditions. A simple mathematical model is developed to explore the impact of treatment defaulting on the transimission dynamics of HCV among injection drug misusers. Numerical simulations are provided to support analytical findings
Influence of gas discharge parameters on emissions from a dielectric barrier discharge excited argon excimer lamp.
No full textThis work is licensed under the Creative Commons Attribution License.A dielectric barrier discharge excited neutral argon (Ar I) excimer lamp has been developed and characterised. The aim of this study was to develop an excimer lamp operating at atmospheric
pressure that can replace mercury lamps and vacuum equipment used in the sterilisation
of medical equipment and in the food industry. The effects of discharge gas pressure, flow rate, excitation frequency and pulse width on the intensity of the Ar I vacuum ultraviolet
(VUV) emission at 126 nm and near infrared (NIR) lines at 750.4 nm and 811.5 nm have been investigated. These three lines were chosen as they represent emissions resulting from deexcitation
of excimer states that emit energetic photons with an energy of 9.8 eV. We observed
that the intensity of the VUV Ar2* excimer emission at 126 nm increased with increasing
gas pressure, but decreased with increasing excitation pulse frequency and pulse width. In
contrast, the intensities of the NIR lines decreased with increasing gas pressure and increased with increasing pulse frequency and pulse width. We have demonstrated that energetic VUV photons of 9.8 eV can be efficiently generated in a dielectric barrier discharge in Ar.African Laser Centre. Laser Research Institute
Pattern of faecal 20-oxopregnane and oestrogen concentrations during pregnancy in wild plains zebra mares
No full textGeneral and Comparative EndocrinologyRegulative endocrine mechanisms influence the reproductive behaviour and success of mammals, but
they have been studied predominantly in domestic and captive animals. The study aims at describing
the pattern of faecal 20-oxopregnane and oestrogen concentrations during pregnancy in wild plains zebra
Equus quagga chapmani. Data were collected during wet and dry seasons 2007?2009. Enzyme Immunoassays
were used to determine 20-oxopregnane and oestrogen concentrations in faecal samples (n = 74)
collected from individual mares (n = 32) whose dates of foaling were known through long-term monitoring.
Hormonal profiles were described with a General Additive Model (GAM: Hormone Days to Foaling).
Faecal 20-oxopregnanes have a complex cycle during pregnancy (GAM, n = 70, R2 = 0.616,
p < 0.001). From 250 days to foaling, faecal 20-oxopregnane concentrations were above the baseline
levels found in non-pregnant mares, peaking in the last 50 days. Faecal oestrogen levels showed a clear
peak in mid-pregnancy (GAM, n = 62, R2 = 0.539, p < 0.001). The sex of the foetus and season had no
detectable effect on hormone concentrations during pregnancy. High levels (>200 ng/g DW) of faecal
20-oxopregnanes associated with high (>160 ng/g DW) faecal oestrogen levels indicate mid-pregnancy
in c.90% of cases (16/17). High faecal 20-oxopregnanes (>200 ng/g DW) and low faecal oestrogen levels
(<160 ng/g DW) indicate late pregnancy, again in c.90% of cases. Two faecal samples would allow the
stage of pregnancy to be determined with confidence