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Search Results: 1 - 10 of 31037 matches for " Thomas Agyei "
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Floral diversity and carbon stocks and of protected forest ecosystem: A case of UENR’s Bat Sanctuary, Sunyani, Ghana  [PDF]
Nat Owusu-Prempeh, Osei Owusu Antobre, Thomas Agyei
Open Journal of Forestry (OJF) , 2018, DOI: 10.4236/ojf.2018.81003
Abstract: The study assesses the functional status of the University of Energy and Natural Resources’ (UENR) bat sanctuary by examining its floral diversity and carbon stocks. Twenty-nine sampling points (plots) were randomly generated by using the ArcGIS random sampling algorithm. Using a three-nest sampling plot of 100m2, 25m2, and 1m2 quadrat, the enumeration of trees (DBH>10cm), saplings (>2cm DBH <10cm) and seedlings (girth <2cm) was undertaken, respectively. Additionally, the diversity of each floral species was computed using the Shannon Wiener diversity index whilst the carbon stocks were estimated using allometric equations. The total carbon stock per plot was derived from the summation of the aboveground carbon (AGC), belowground carbon (BGC) and deadwood carbon (DWC). In sum, 450 floral individuals belonging to 47 species and 22 families were enumerated with Bignoniaceae (16.4%), Apocynaceae (10.0%), Caesalpiniaceae (9.2%) and Rubiaceae (8.8%) being the most common families within the protected area (PA). The average carbon sequestered per hectare of the PA was 2,789.3 tons. However, there was no significant difference (p>0.05) between the 10m buffer created and the core area with respect to species diversity and carbon stocks. The study has provided valuable information on the functional status of the bat sanctuary which will help promote its conservation for sustained provision of ecosystem services.
Insecticide resistance profiles for malaria vectors in the Kassena-Nankana district of Ghana
Francis Anto, Victor Asoala, Thomas Anyorigiya, Abraham Oduro, Martin Adjuik, Seth Owusu-Agyei, Dominic Dery, Langbong Bimi, Abraham Hodgson
Malaria Journal , 2009, DOI: 10.1186/1475-2875-8-81
Abstract: Indoor resting Anopheles mosquitoes were collected. Blood-fed and gravid females were allowed to oviposit, eggs hatched and larvae reared to 1–3 days old adults and tested against permethrin 0.75%, deltamethrin 0.05%, cyfluthrin 0.15%, lambdacyhalothrin 0.1% and DDT 4%, based on WHO methodology. PCR analyses were carried out on a sub-sample of 192 of the An. gambiae for sibling species complex determination. Resistance to pyrethroids and DDT was determined by genotyping the knock-down resistance kdr gene mutations in the study area.A total of 9,749 1–3 days-old F1 female Anopheles mosquitoes were exposed to the insecticides. Among the pyrethroids, permethrin, 0.75% had the least knockdown effect, whilst cyfluthrin 0.15%, had the highest knock-down effect. Overall, no difference in susceptibility between An. gambiae 93.3% (95% CI: 92.5–94.1) and An. funestus 94.5% (95% CI: 93.7–95.3) was observed when exposed to the pyrethroids. Similarly, there was no difference in susceptibility between the two vector species (An. gambiae = 79.1% (95% CI: 76.6–81.8) and An. funestus = 83.5% (95% CI: 80.2–86.4) when exposed to DDT. Overall susceptibility to the insecticides was between 80% and 98%, suggesting that there is some level of resistance, except for cyfluthrin 0.15%. The kdr PCR assay however, did not reveal any kdr mutations. The analysis also revealed only the molecular M (Mopti) form.The findings in this study show that An. gambiae and An. funestus, the main malaria vector mosquitoes in the Kassena-Nankana district are susceptible to the insecticides being used in the treatment of bed nets in the malaria control programme. There is however, the need for continuous monitoring of the pyrethroids as the efficacy is not very high.Malaria is a major public health problem in Ghana. The strategy of the National Malaria Control Programme is based on effective case management and the use of insecticide treated bed nets among vulnerable groups, such as children under five years o
Assessing malaria control in the Kassena-Nankana district of northern Ghana through repeated surveys using the RBM tools
Seth Owusu-Agyei, Elizabeth Awini, Francis Anto, Thomas Mensah-Afful, Martin Adjuik, Abraham Hodgson, Edwin Afari, Fred Binka
Malaria Journal , 2007, DOI: 10.1186/1475-2875-6-103
Abstract: Data were collected from mothers/caretakers on signs/symptoms of the most recent malaria attack for their under five year old children; the management actions that they took and their perception of health services provided at the health facilities, bednet use, antenatal attendance and place of delivery for the most recent pregnancy, malaria prophylaxis during their last pregnancy. Community health workers and herbalist/traditional healers were also interviewed about the types of health services they provide to community members.The results revealed a significant improvement in knowledge among mothers/caretakers over the three-year period; this affected caretakers' initial management of illnesses of their young children. The management in terms of the type and dosage of drugs used also improved significantly (p < 0.0001) over the period. Reported insecticide-treated bed net use among children under-five years and pregnant women significantly increased between 2000 and 2003 (p < 0.0001). Health professionals had improved on adoption of their quality of care roles.The intensification of malaria control activities and awareness creation in this district over a three year period had started demonstrating positive results towards reducing malaria disease burden.Periodic performance assessments through surveys as described and prompt feedback of results to stakeholders in the locality serves as a catalyst to improving malaria control in malaria-endemic countries.Malaria is the world's most important tropical parasitic disease; killing more people than any other communicable disease, except tuberculosis. Prevention is the best protection from malaria. It includes individual protection, such as the use of insecticide-treated bed nets, mosquito repellants and drug prophylaxis for pregnant women; community measures, such as the control of mosquito breading sites, insecticide spraying and drainage.Morbidity and mortality are particularly high among pregnant women, young childre
Determination of surface fluxes using a Bowen ratio system
VCK Kakane, EK Agyei
West African Journal of Applied Ecology , 2006,
Abstract: Components of the surface fluxes of the energy balance equation were determined using a Campbell Bowen ratio system. The fluxes are obtained by the energy balance Bowen ratio technique, a gradient method that uses vertical gradients of temperature and vapour pressure in combination with point measurements of net radiation and soil heat flow from two sets of soil sensors. The Bowen ratio was measured as the ratio of air temperature and vapour pressure gradients between two fixed heights within 6 m of the surface. Net radiation (Rn) was measured using net radiometers. Soil heat flux (Qg) was measured with ground heat flux plates and the change in energy storage of the layer of soil above the heat flux plates was computed using direct measurements of soil temperature and moisture content. Measurements made every 20 min are stored in the Campbell data logger. Results show most of the net radiation is converted to latent heat when there are more water available for evaporation. Estimates of sensible and latent heat flux have an accuracy of ± 10% of the measured value.
The Dynamics of Natural Plasmodium falciparum Infections
Ingrid Felger, Martin Maire, Michael T. Bretscher, Nicole Falk, André Tiaden, Wilson Sama, Hans-Peter Beck, Seth Owusu-Agyei, Thomas A. Smith
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045542
Abstract: Background Natural immunity to Plasmodium falciparum has been widely studied, but its effects on parasite dynamics are poorly understood. Acquisition and clearance rates of untreated infections are key elements of the dynamics of malaria, but estimating these parameters is challenging because of frequent super-infection and imperfect detectability of parasites. Consequently, information on effects of host immune status or age on infection dynamics is fragmentary. Methods An age-stratified cohort of 347 individuals from Northern Ghana was sampled six times at 2 month intervals. High-throughput capillary electrophoresis was used to genotype the msp-2 locus of all P. falciparum infections detected by PCR. Force of infection (FOI) and duration were estimated for each age group using an immigration-death model that allows for imperfect detection of circulating parasites. Results Allowing for imperfect detection substantially increased estimates of FOI and duration. Effects of naturally acquired immunity on the FOI and duration would be reflected in age dependence in these indices, but in our cohort data FOI tended to increase with age in children. Persistence of individual parasite clones was characteristic of all age-groups. Duration peaked in 5–9 year old children (average duration 319 days, 95% confidence interval 318;320). Conclusions The main age-dependence is on parasite densities, with only small age-variations in the FOI and persistence of infections. This supports the hypothesis that acquired immunity controls transmission mainly by limiting blood-stage parasite densities rather than changing rates of acquisition or clearance of infections.
Good Clinical Laboratory Practices Improved Proficiency Testing Performance at Clinical Trials Centers in Ghana and Burkina Faso
Faisal Ibrahim, David Dosoo, Karl C. Kronmann, Issa Ouedraogo, Thomas Anyorigiya, Haruna Abdul, Sirima Sodiomon, Seth Owusu-Agyei, Kwadwo Koram
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039098
Abstract: Background The recent drive towards accreditation of clinical laboratories in Africa by the World Health Organization – Regional Office for Africa (WHO-AFRO) and the U.S Government is a historic step to strengthen health systems, provide better results for patients and an improved quality of results for clinical trials. Enrollment in approved proficiency testing (PT) programs and maintenance of satisfactory performance is vital in the process of accreditation. Passing proficiency testing surveys has posed a great challenge to many laboratories across sub-Saharan Africa. Our study was aimed at identifying the causes of unsatisfactory PT results in clinical research laboratories conducting or planning to conduct malaria vaccine trials sponsored by the National Institutes of Health (NIH). Methodology PT reports for 2009 and 2010 from the College of American Pathologists (CAP) for the laboratories were reviewed as part of the process. Errors accounting for unsatisfactory results were classified into clerical, methodological, technical, problem with PT materials, and random errors. A training program on good clinical laboratory practices (GCLP) was developed for each center to address areas for improvement. Results The major cause of PT failure in the four centers was methodological. The application of GCLP improved the success rate in the PT surveys from 58% in 2009 to 88% in 2010. It also decreased the error rate on PT by 35%. Conclusion A previous report from the CAP- PT participating laboratories indicated that the major causes of error were clerical. These types of errors were predominantly made in laboratories in the US, with much more experience in quality control, and varied significantly from what we found. In our centers in sub-Saharan Africa, methodological errors, and not clerical errors, accounted for the vast majority of errors. A process was started for continuous improvement which has decreased methodological errors by 35%, but more improvement is needed.
Experimental Evaluation of the Attenuation Effect of a Passive Damper on a Road Vehicle Bumper  [PDF]
A. Agyei-Agyemang, G. Y. Obeng, P. Y. Andoh
World Journal of Engineering and Technology (WJET) , 2014, DOI: 10.4236/wjet.2014.23021
Abstract: To mitigate the degree of damage to passengers caused by automobile collisions, a friction damper was built and used in experimental tests to test its effectiveness in impact energy attenuation. The study revealed that energy absorption capacity of a bumper can be improved with the addition of a friction damper. The results revealed that the addition of the friction damper to an automobile bumper to give a bumper-damper system could attenuate about 32.5 % more energy than with the bumper alone. It can be concluded that the effectiveness of automobile bumpers to withstand impact of vehicles by absorbing the kinetic energy from the impact can be improved with the use of a passive friction damper. That is, a passive friction damper system could be used to attenuate more road vehicle impact energy in collisions.
Distinguishing land use types using surface albedo and normalized difference vegetation index derived from the SEBAL model for the Atankwidi and Afram sub-catchments in Ghana
Tayari Salifu,Wilson Agyei Agyare
Journal of Engineering and Applied Sciences , 2012,
Abstract: Distinguishing land use types is mostly done through field surveys which does not easily capture the spatial changes in the land use/cover types. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) model was used to estimate surface albedo and NDVI, for different land use/cover types for two sub-catchments (i.e., Atankwidi and Afram) in the Volta Basin of Ghana. The mean coefficient of variation (CV) for individual land use/cover types compared to the mean CV for a given site was then used to distinguish among the land use/cover types. It was found that these parameters derived from the SEBAL model can be used to distinguish among different land use/cover types in the two sub-catchments. SEBAL estimates for surface albedo and NDVI across the different land use/cover types varied from 0.05 to 0.22 and -0.41 to 0.38, respectively. The range of CVs for surface albedo and NDVI, were 5-22% and 7-175%, respectively across the different land use/cover types for the two catchments. The results of this study demonstrate that SEBAL’s derived surface albedo and NDVI can be used to distinguish land use/cover types in catchments similar to those of the study areas with few ground measurements.
The Impact Of Contingent Factors On Performance Measures In The Rural Banks Of Ashanti Region Of Ghana
Ben K. Agyei-Mensah
International Journal of Academic Research in Business and Social Sciences , 2012,
Abstract: The study examined the application of performance measurement techniques in the rural banks in the Ashanti Region of Ghana. Management accounting theory suggests that two different measures of branch performance should be computed; one to evaluate the economic performance of each branch and the other to evaluate the performance of branch managers (managerial performance). The purpose of the study was to ascertain the type of performance measures that are applied in these institutions. That is whether or not the management of these banks has been applying financial and/or non financial performance measures in assessing the performance of their branches and the managers of those branches In addition the study examined the impact of contingent factors on the use of financial and non financial performance measures. Though, all the respondents stated that they used both financial and non financial performance measures, there was heavy reliance on financial measures. The study found that neither the balanced scorecard nor the Tableau de Bord have ever been used as performance measures. The study findings also revealed that profitability (i.e. Operating profit margin, Return on shareholders' capital) and liquidity (i.e. current ratio and working capital ratio) have varied impact on the use of performance measures by the rural banks in the Ashanti Region of Ghana.
Working Capital Management Practices of small Firms in the Ashanti Region of Ghana
Ben K. Agyei-Mensah
International Journal of Academic Research in Business and Social Sciences , 2012,
Abstract: In a developing economy like Ghana, the contribution of small firms to the employment of the youth is highly recognized, but their contribution towards revenue to the national budget seems negligible. The reason is that some of the firms do not manage their working capital as expected and this has affected the viability of their businesses. The study revealed that the operators of small firms possess limited formal education, weak managerial and financial management skills within the sector. They also lack qualified accounting staff and suitable accounting software which are motivators to effective working capital management practices. Owners/managers were found to act as barriers to efficient usage of working capital management practices. Recommendations on credit control and collection policies, the importance of the use of computer spreadsheets, training and education which the study found to be problems with the sample small firms have been suggested to the owners/managers.
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