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- ItemDYNAMICS OF MULTI INFECTIONS DISEASE (MALARIA-ELEPHANTIASIS-ZIKA VIRUS) TRANSMISSION IN MOSQUITO ENDEMIC REGIONS(KNUST, 2019-10) MENSAH, JOHN-AMOAHMosquitoes are one of the deadliest insects in the world. Their ability to carry and spread disease to humans cause millions of deaths every year. The worldwide incidence of diseases caused by mosquitoes has risen 30-fold in the past 30 years, and more countries are reporting their first outbreaks of the mosquito caused diseases. Zika, Malaria, and Elephantiasis are all transmitted to humans by the Aedes aegypti mosquito. More than half of the world’s population live in areas where this mosquito species are present. Sustained mosquito control efforts are important to prevent outbreaks from these diseases. There are several different types of mosquitoes and some have the ability to carry many different diseases. The study presents a multi-infections system model to study the transmission dynamics of Malaria, Zika-Virus and Elephantiasis in an endemic region such as Kedougou in the South Eastern part of Senegal and other parts of the world. This makes it possible to have multiinfections of the three diseases simultaneously. The main objective of this work was to study the dynamics of multi-infections (Malaria-Elephantiasis-Zika virus) and transmission through the use of mathematical model, to determine the stability of the multi-infections model, the co-infections model and also study the single models for individual diseases including Malaria, Zika and Elephantiasis. The disease-free equilibrium is performed and it was shown to be globally asymptotically stable when the associated threshold number known as the basic reproduction number for the model is R0 < 1. Investigation on the existence and stability of equilibria was also derived, the model was found to exhibit backward bifurcation. Thus, R0 less than unity is not sufficient to eradicate the disease from the population and there was the need to lower R0 below a certain threshold for effective disease control. Sensitivity analysis was performed to determine parameters that have high influence on the basic reproduction number. Optimal control policies was also used as measures to eradicate the diseases from the system.
- ItemPRODUCTIVITY, PROFITABILITY AND COST EFFECTIVENESS OF SEED YAM PRODUCTION UNDER POSITIVE SELECTION TECHNOLOGY IN GHANA AND NIGERIA(KNUST, 2019-07) Jonas, Osei-AduThe main challenge that necessitated this study was the limited empirical evidence on Total Factor Productivity (TFP), Cost Effectiveness (CE) and Profitability of seed yam production from Positive Selection (PS) technology as a viral control measure. This study was therefore aimed at estimating TFP, profitability and CE of seed yam production using PS technology. Quasi-experimental design was used for both data collection and analysis through the use of qualitative and quantitative research methods. Through multi-stage sampling, 368 seed yam farmers comprising of PS and Non-PS technology beneficiaries under the Community Action in improving Farmer saved seed yam (CAY-Seed) project were sampled. Qualitative data was collected through focus group discussions with the aid of a checklist. A formal survey using a standardised questionnaire was conducted across project communities in Ghana and Nigeria to generate quantitative data. TFP, Profitability and CE from PS technology were estimated using the metafrontier framework, Net Return on Investment (NRI) and Incremental Cost Effectiveness Ratio (ICER), respectively. Farmer perceptions and constraints from the qualitative analysis are presented in the form of tag clouds based on focus group discussions. TFP (0.758) from seed yam production using PS technology is significantly higher than the non-use (0.700) such that the use of PS technology leads to 5.8% productivity improvement. Metatechnology Ratio (MTR) from using PS technology (0.934) is significantly higher than Non-PS technology (0.911) with a technology gap of 7% and 9%, respectively. Land, seed yam, agrochemicals, neem powder application and labour are significant determinants of productivity with neem application having the greatest effect. Technical inefficiency in seed yam production is determined by sex, experience in yam production, educational level of farmer and extension contact. Producing seed yam under PS technology was cost effective with ICER of US$ 54.0/t as compared to US$ 1,348.72/t for not using PS technology. With a NRI of 56.80 %, seed yam production under PS technology is profitable compared to Non-PS (30.11%). It is therefore recommended that the extension system in Ghana and Nigeria should promote PS technology as a viral control measure for seed yam production due to its profitability, CE and high productivity.
- ItemBREEDING FOR TOLERANCE TO SALT STRESS IN RICE USING A NEW TOLERANCE DONOR, MADINA KOYO(KNUST, 2019-11) AMOAH, NANA KOFI ABAKASalt stress is a major constraint that reduces productivity of many rice fields across the world. Susceptibility of the crop comes within the first few weeks of establishment and later during the reproductive stage. Many studies conducted to improve the adaptability of the crop to saline soils has focused on introgression alleles from a few donor genetic background. To broaden the genetic base of tolerant alleles, a new salt stress donor cultivar, “Madina Koyo” was used in developing a set of introgression lines with a farmer preferred indica variety, „Sahel 317‟. To identify lines that are tolerant to the stress at the two most susceptible stages, F2 derived F3 lines (F2:3) and F3:4 lines were evaluated at the early seedling and reproductive stages respectively. To better understand the regions controlling tolerance in this new donor and to validate previously reported regions, QTL mapping was undertaken using Single Nucleotide Polymorphism (SNP) analysis from Genotype by sequencing (GBS). Salt stress caused a drastic reduction of 72% in grain yield among the F2:3 progenies. Altogether, an average reduction of 63.4% was observed for all fitness related traits among selected F3:4 progenies at the early seedling stage. A total of 45 progenies had better or comparable grain yield to the donor parent “Madina Koyo” and were adjudged to be tolerant at the reproductive stage. Subsequently, another 46 progenies, representing 5% of the evaluated progenies, recorded an average SES score 1-3 and were rated as tolerant to salt stress at the early seedling stage. Out of the combined 91 progenies, only one progeny, ARS1181-1-6-27, was observed to be tolerant to salt stress at both growth stages. Another four progenies (ARS1181-1- 7-6, ARS1181-1-6-6, ARS1181-1-8-26 and ARS1181-1-10-1) combined tolerance at the seedling stage with better yield stability. These five promising progenies should be further evaluated with the aim of releasing as per se or be used as parents in future iii forward breeding efforts. A high-density genetic linkage map was constructed for the 12 rice chromosomes using 3698 SNP markers. Composite interval mapping identified 46 QTLs on 10 chromosomes (1, 2, 3, 4, 7, 8, 9, 10, 11 and 12) for SES, shoot length, shoot dry weight and root dry weight. No QTL was identified for root length. Thirty three out of the 46 QTLs were shoot-related QTLs while five were root related. Breeders should, therefore, focus on shoot related traits when evaluating rice germplasm for salt tolerance at the seedling stage. None of the QTLs identified was mapped in the region of previously reported major effect QTL Saltol on chromosome 1, suggesting that Madina Koyo controls tolerance from a different region by a different QTL(s). Six out of the 46 (qSDW1.1, qSDW2, qSL1.1, qSL2.2, qSL2.3 and qSL2.4) were major effect QTLs with phenotypic contributions ranging from 11% - 99%. Comparison with literature suggests the novelty of these major effect QTLs. Fine mapping of these novel QTLs in a different genetic background is necessary to confirm their stability and use in breeding to enhance the level of tolerance through MAS for the pyramiding of different QTLs to one genetic background
- ItemSerum angiopoietins (ANG -1) and (ANG-2) levels as prognostic biomarkers for differentiating severe malaria from uncomplicated malaria in a Ghanaian population.(KNUST, 2023-06) Boadi, EnochMalaria is classified as either uncomplicated malaria or severe malaria. The principle that underly the progression of uncomplicated malaria to severe malaria is still unclear. This study aimed at assessing serum angiopoietins (ANG -1) and (ANG-2) levels as prognostic biomarkers for differentiating severe malaria from uncomplicated malaria in a Ghanaian population. A descriptive cross-sectional study was employed to sample 166 study participants of which forty-two (42) were apparently healthy controls, seventy-eight (78) were uncomplicated malaria cases, and forty-six (46) were severe malaria cases. Blood samples were taken and analysed for full blood count, liver function test, renal function test, and serum angiopoietins. Statistical analyses were carried out using Graph Pad Prism 9 software. The median and interquartile ranges, Mann-Whitney U test, and Kruskal-Wallis’s analysis were done to compare groups. The Ang-1 levels in the severe malaria group were lower (3.8 ng/L, IQR: 2.2 – 12.7) in comparison to the uncomplicated malaria group (6.3 ng/L, IQR: 3.3 – 8.0) and healthy controls (9.6 ng/L, IQR: 3.5 – 15.3). Ang-2 levels were higher in the severe malaria group (19.1ng/L, IQR: 9.0 – 25.8) compared to the uncomplicated malaria group (15.7ng/L, IQR: 2.6 – 27.4). The Ang-1 levels showed a high predictive ability of 94.9% to predict severe malaria from uncomplicated malaria whiles Ang-2, and Ang-2/Ang-1 ratio levels showed no predictive ability in discriminating malaria severity. Some hematological parameters, biochemical parameters, and parasite density were also associated significantly with malaria severity. In conclusion, the results suggest that Ang-1 and Ang-2 do not have the potential to serve as biomarkers of both severe and uncomplicated forms of malaria in a Ghanaian population.
- ItemDevelopment of a model framework for simultaneous synthesis and selection of Anaerobic Digester Structures(November, 2019) Rejoice Ntiriwaa Ossei-Bremang;The anaerobic treatment process has increasingly been recognized as an efficient technology for sustainable nutrient recovery, renewable energy generation, and environmental sanitation due to its strong potential to mitigate current energy resource and climate change challenges. However, the success of industrial-scale anaerobic digestion is only possible if the following two prerequisite factors are met: availability of a sustainable supply of organic feedstock and design of optimal process configurations containing appropriate digester subunits that are well adapted to the characteristics of the feedstock of interest. A lot of combinations of the fundamental anaerobic digester types exist, which becomes impossible to test all the possibilities in order to determine the one with the absolute best performance. This study did not focus attention on devising new digesters with the aim of improving the performance of the system, but rather optimally arranged some combinations of plug flow reactors (PFRs) and continuous stirring tank reactor (CSTR) systems. The objective of study was to establish a framework based on multi-criteria decision analysis, for optimal selection of anaerobic digesters and practical implementation of digester networks, which is amendable to any substrate and digester configuration. Anaerobic treatability study was performed using pineapple waste, pig waste, abattoir waste and food waste to obtain cummulative biogas yield curves followed by development of the digester configurations using the attainable region technique. A hybrid Analytical Hierachy Process and Fuzzy Technique for Order Preference by Similarity to Ideal Solution was used in the selection of plug flow anaerobic digesters for the configurations. The following biogas volumes were obtained at the end of the 30 days retention period; for pig waste, for abattoir waste, for food waste and for pineapple waste. Quantity of feedstock used was 5kg per sample. A novel framework for the selection of multi stage anaerobic digesters has been presented. Optimal digester configurations obtained differ based on substrate used. The selected plug flow anaerobic digesters for subunit were Expanded Granular Sludge Bed for scenario 1, scenario 2 and scenario 3 were Anaerobic Baffled Reactor.