Browsing by Author "Aidoo, E.K."
Now showing 1 - 9 of 9
Results Per Page
Sort Options
Item Analysis of Exchange Rates as Time-Inhomogeneous Markov Chain with Finite States(Journal of Applied Mathematics, 2022) Mettle, F.O.; Boateng, L.P.; Quaye, E.N.B.; Aidoo, E.K.; Seidu, I.Irrespective of whether the test for homogeneity is significant or not, most researchers assume time-homogeneity in analysing Markov chains due to scanty literature on the analysis of time-inhomogeneous Markov chains. Based on the assumption that, for each point in time in the future, a stochastic process will be subjected to a randomly selected transition matrix from an ergodic set of transition matrices the process was subjected to in the recent past, a methodology was proposed for analysing the long-run behaviours of time-inhomogeneous Markov chains. The proposed model was implemented to historical data consisting of the exchange rate of cedi-dollar, cedi-pound, and cedi-euro spanning over 6 years (January 2012 to December 2017). The results show that under certain “closeness” conditions, the long-run behaviours of the time-inhomogeneous case are almost identical to those of the time-homogeneous case. The paper asserted that even if the Markov chain exhibit time-inhomogeneity, analysing the Markov chain under the assumption of time-homogeneity is a step in the right direction under certain “closeness” conditions; otherwise, the proposed method is recommended. It was also found that investing in dollars yields better returns than the other currencies in Ghana.Item Analysis of Investment Returns as Markov Chain Random Walk(International Journal of Mathematics and Mathematical Sciences, 2024) Mettle, F.O.; Agyekum, L.; Aidoo, E.K.; Dowuona, C.O.N.The main objective of this paper is to analyse investment returns using a stochastic model and inform investors about the best stock market to invest in. To this effect, a Markov chain random walk model was successfully developed and implemented on 450 monthly market returns data spanning from January 1976 to December 2020 for Canada, India, Mexico, South Africa, and Switzerland obtained from the Federal Reserves of the Bank of St. Louis. Limiting state probabilities and six-month moving crush probabilities were estimated for each country, and these were used to assess the performance of the markets. Te Mexican market was observed to have the lowest probabilities for all the negative states, while the Indian market recorded the largest limiting probabilities. In the case of positive states, the Mexican market recorded the highest limiting probabilities, while the Indian market recorded the lowest limiting probabilities. The results showed that the Mexican market performed better than the others over the study period, whilst India performed poorly. These findings provide crucial information for market regulators and investors in setting regulations and decision-making in investment.Item Association of TNF-Alpha, MBL2, NOS2, and G6PD with Malaria Outcomes in People in Southern Ghana(Genetics Research, 2022) Fugtagbi, G.; Otu, P.S.; Abdul-Rahman, M.; Aidoo, E.K.; Lo, A.C.; Gyan, B.A.; Afrane, Y.A.; Amoah, L.E.Background. One major issue that has set back the gains of the numerous malaria control interventions that national malaria control programs have implemented is asymptomatic malaria. Certain host genetic factors are known to influence symptomatic malaria; however, not much is known about how host genetics influences the acquisition of asymptomatic malaria. Methods. Genomic DNA was extracted from whole blood collected from 60 symptomatic and 149 nonfebrile (asymptomatic, N 109, and uninfected, N 40) volunteers aged between 2 and 69 years from a high (Obom) and a low (Asutsuare) malaria transmission setting in Southern Ghana. Restriction fragment length polymorphism (RFLP) was used to determine polymorphisms at the MBL2 54, TNF-α 308, NOS2 954, and G6PD 202/376 gene loci. Results. Polymorphisms at the MBL2 54 and TNF-α 308 loci were significantly different amongst the three categories of volunteers in both Asutsuare (p 0.006) and Obom (p 0.05). I Asutsuare, a low malaria transmission area, the allele G has significantly higher odds (3.15) of supporting asymptomatic malaria as against symptomatic malaria. )ere were significantly higher odds of TNF-α genotype GA being associated with symptomatic malaria as against asymptomatic malaria in both sites, Obom (p 0.027) and Asutsuare (p 0.027). )e allele B of the G6PD gene was more prevalent in symptomatic rather than asymptomatic parasite-infected individuals in both Obom (p 0.001) and Asutsuare (p 0.003). Conclusion. Individuals in Southern Ghana carrying the TNF-α 308 GA genotype are more likely to exhibit symptoms of malaria when infected with the malaria parasite as opposed to harboring an asymptomatic infection. Also, the B allele of the G6PD gene is likely to prevent a P. falciparum-infected person from exhibiting symptoms and thereby promote asymptomatic parasite carriage.Item Determinants of Household-Level Food Storage Practices and Outcomes on Food Safety and Security in Accra, Ghana(Foods, 2022) Afriyie, E.; Asem, F.E.; Aidoo, E.K.; et al.Household-level food storage can help families save money, minimize food waste, and enhance food safety and security. Storing food within households may, however, be affected by domestic routines like food shopping and cooking. Therefore, it is essential to evaluate how consumers’ attitudes and behaviors influence food storage at the household level. This study aimed to assess the determinants of household-level food storage, ascertain consumers’ behavior and perception towards food storage, and assess the effect of household-level food storage on food safety, wastage, food expenditure and security. Dzorwulu and Jamestown, both located in Accra, Ghana, served as the study’s primary sites. The study employed a survey and structural equation modeling to evaluate key determinants of household-level food storage practices and their impacts. A semi-structured questionnaire was administered to 400 food household heads, sampled using systematic sampling procedure. The results showed that food shopping drives food storage. There was, however, a significant negative association (p < 0.001) between food shopping and time of food storage. Although cooking impedes household-level food storage; there was significant positive association (p < 0.001) between frequency of cooking and storage period of food commodities. The findings also revealed that household-level food storage promotes food safety, reduces food expenditure and waste, and contributes to enhancing food security by 43%. To promote household-level food storage and ensure food safety and security, future study should concentrate on enhancing conventional household-level food storage practices that are efficient, cheaper and easily implementable.Item Estimation Of Long-Run Probability Of Zero Offspring Using Branching Processes In Varying Environment(University Of Ghana, 2022-04) Aidoo, E.K.There are many challenges associated with both young and ageing population. If a country experiences a younger population, there’s a tendency for high unemployment rates and social vices. On the other hand, an ageing population typically results in a low labour force and high dependency ratios. Countries that tend to solve the problem of a young population initiate policies to control birth rates. However, these policies gradually lead to an ageing population before being revised, due to high costs associated with regular monitoring of population dynamics. Therefore, there is a need to develop a less costly method to monitor population dynamics and estimate the expected time to revise population policies. This study employed a more general theorem and a corollary based on ideas of probability generating functions in a branching process to come out with a method to solve the problem. The method was applied to both hypothetical and empirical data in the branching processes. The empirical data were obtained from Demographic and Health Surveys (DHS) for seven selected countries. The results from the study revealed that under certain closeness conditions, both constant and random environments yield similar results. Hence, using the method under the constant environment, which is easier, is a step in the right direction; otherwise, the proposed method for the random environment should be used. Burkina Faso recorded the youngest population, while Philippines recorded the least country with younger population. Results from the spectral analysis estimated that population policy for the selected countries should be revised between 34 to 40 years. The study recommended that the proposed model should be used to monitor population dynamics regularly. Also, population policies should be guided by appropriate time frame depending on the country’s demographic characteristics.Item Government Stability in the Remittance-Economic Growth Link in Ghana(International Journal of Applied Economics, Finance and Accounting, 2022) Adu-Darko, E.; Aidoo, E.K.Several studies have revealed that many factors affect economic growth. Remittances and government stability have been identified as two of these factors. Over the years, remittances have become a major source of financial inflows, especially in Ghana. This study examines the role of government stability in the remittance-economic growth relationship in Ghana. Annual time series data from 1984 to 2020 was extracted from the World Development Indicators (WDI) and the International Country Risk Guide (ICRG). An ARDL model with a level structural break was estimated. The results show, first, that a cointegration relationship exists among the variables in the presence of structural breaks. Secondly, remittances and government stability have a significant, positive long-run impact on economic growth, while there is no significant impact of GDPPC and government stability on remittances was found. Thirdly, in the short run, remittances and government stability are not significantly associated with growth. The role of remittances in the economic growth of Ghana important. When remittances increase, economic growth will likewise increase. Government policy-making should create an enabling environment to channel remittances into productive uses, including entrepreneurial ventures. Remittances must be received through proper channels for easy accountability, and government stability should be complemented by good governance to further foster economic growth.Item Helicobacter pylori cagA and vacA genes in dyspeptic Ghanaian patients(BioMed Central Ltd., 2017) Archampong, T.N.; Asmah, R.H.; Aidoo, E.K.; Wiredu, E.K.; Gyasi, R.K.; Adjei, D.N.; Beleza, S.; Bayliss, C.D.; Krogfelt, K.Background: Helicobacter pylori infection is prevalent in Ghana. The development of gastro-duodenal disease is dependent on virulence of the infecting strain, host susceptibility and environmental factors. Helicobacter pylori cagA and vacA strains induce more inflammation, ulceration and oncogenesis. Here, for the first time we present data on H. pylori cagA and vacA genes and their association with gastro-duodenal disease in Ghana. A total of 159 patients with dyspepsia at Korle-Bu Teaching Hospital, Accra, were investigated for H. pylori with urease-CLO, of which 113 (71.1%) were positive. Genomic DNA was extracted from antral biopsies using QIAGEN DNeasy kit. Detection of H. pylori vacA and cagA genes were determined by PCR as previously described. Results: In total, 110 (69.2%) vacAs1, 71 (44.7%) vacAm1, 35 (22.0%) vacAm2, 77 (48.4%) cagA-(hydrophilic region) and 109 (68.6%) cagA-(internal duplication region) were detected. In multivariate analysis, duodenal ulcer was more likely than other diagnoses to have detectable cagA-(hydrophilic region) (OR 3.1 CI 1.2-7.9) or vacAs1m1 (OR 6.5 CI 1.2-34.0). Conclusions: Majority of biopsies were colonized with H. pylori harboring both cagA and vacA. H. pylori cagA-(internal duplication region) was more prevalent than cagA-(hydrophilic region). Duodenal ulcer was more likely than other diagnoses to have detectable cagA-(hydrophilic region) or vacAs1m1.Item Reactive case detection of Plasmodium falciparum in western Kenya highlands: effective in identifying additional cases, yet limited effect on transmission(Malaria Journal, 2018-03) Aidoo, E.K.; Afrane, Y.A.; Machani, M.G.; Chebore, W.; Lawson, B.W.; Atieli, H.; Kariuki, S.; Lee, M.C.; Koepfli, C.; Zhou, G.; Githeko, A.K.; Yan, G.Background Identifying asymptomatic reservoirs of malaria parasites using index cases as entry points into the community is potentially a cost-effective way towards achieving malaria elimination. Methods Within 1 year, 1430 confirmed malaria cases were identified in Marani hospital, western Kenya. Fifty cases were followed up, and 108 index case household members and 612 neighbours within a 100 m radius were screened. As controls, samples were collected from 510 individuals matched with index cases and located at a distance of ≥ 500 m from them. Infections were diagnosed by microscopy and PCR while simultaneously collecting malaria vectors indoor using pyrethrum spray catches. Results In the index case and neighbour households, the prevalence of infection was approximately twice as high as in control households (by PCR: index cases households: 28.9%, neighbours: 25.3%, matched controls: 12.9%). In index case households, the indoor vector density (Anopheles gambiae and Anopheles funestus) was higher (0.46 female/house/night) than in neighbouring (0.31 f/h/n) and control houses (0.29 f/h/n). Conclusions Screening index case households and neighbours approximately doubles the chance to detect asymptomatic infections compared to randomly selected households. However, even if all cases were followed up, only a small proportion (˂ 10%) of the asymptomatic reservoir in the population would have been identified. Control programmes need to weigh the increased chance to find cases around index cases vs. the logistical challenges to target this subgroup within the population.Item Reactive Case Detection Strategy for Malaria Control and Elimination: A 12 Year Systematic Review and Meta-Analysis from 25 Malaria-Endemic Countries(Tropical Medicine Infection Disease, 2023) Aidoo, E.K.; Aboagye, F.T.; Amoah, L.; et al.Reactive case detection (RACD) is the screening of household members and neighbors of index cases reported in passive surveillance. This strategy seeks asymptomatic infections and provides treatment to break transmission without testing or treating the entire population. This review discusses and highlights RACD as a recommended strategy for the detection and elimination of asymptomatic malaria as it pertains in different countries. Relevant studies published between January 2010 and September 2022 were identified mainly through PubMed and Google Scholar. Search terms included “malaria and reactive case detection”, “contact tracing”, “focal screening”, “case investigation”, “focal screen and treat”. MedCalc Software was used for data analysis, and the findings from the pooled studies were analyzed using a fixed-effect model. Summary outcomes were then presented using forest plots and tables. Fifty-four (54) studies were systematically reviewed. Of these studies, 7 met the eligibility criteria based on risk of malaria infection in individuals living with an index case < 5 years old, 13 met the eligibility criteria based on risk of malaria infection in an index case household member compared with a neighbor of an index case, and 29 met the eligibility criteria based on risk of malaria infection in individuals living with index cases, and were included in the meta-analysis. Individuals living in index case households with an average risk of 2.576 (2.540–2.612) were more at risk of malaria infection and showed pooled results of high variation heterogeneity chi-square = 235.600, (p < 0.0001) I2 = 98.88 [97.87–99.89]. The pooled results showed that neighbors of index cases were 0.352 [0.301–0.412] times more likely to have a malaria infection relative to index case household members, and this result was statistically significant (p < 0.001). The identification and treatment of infectious reservoirs is critical to successful malaria elimination. Evidence to support the clustering of infections in neighborhoods, which necessitates the inclusion of neighboring households as part of the RACD strategy, was presented in this review.