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Search Results: 1 - 10 of 493 matches for " Gideon Okpoti Tetteh "
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Automatic Generation of Water Masks from RapidEye Images  [PDF]
Gideon Okpoti Tetteh, Maurice Sch?nert
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.310003
Abstract:

Water is a very important natural resource and it supports all life forms on earth. It is used by humans in various ways including drinking, agriculture and for scientific research. The aim of this research was to develop a routine to automatically extract water masks from RapidEye images, which could be used for further investigation such as water quality monitoring and change detection. A Python-based algorithm was therefore developed for this particular purpose. The developed routine combines three spectral indices namely Simple Ratios (SRs), Normalized Green Index (NGI) and Normalized Difference Water Index (NDWI). The two SRs are calculated between the NIR and green band, and between the NIR and red band. The NGI is calculated by rationing the green band to the sum of all bands in each image. The NDWI is calculated by differencing the green to the NIR and dividing by the sum of the green and NIR bands. The routine generates five intermediate water masks, which are spatially intersected to create a single intermediate water mask. In order to remove very small waterbodies and any remaining gaps in the intermediate water mask, morphological opening and closing were performed to generate the final water mask. This proposed algorithm was used to extract water masks from some RapidEye images. It yielded an Overall Accuracy of 95% and a mean Kappa Statistic of 0.889 using the confusion matrix approach.

Grain Size and Major Oxide Analyses of Selected Anthill Soils from Winneba Area, Ghana  [PDF]
George Mensah Tetteh, Julian Kuundaah Angwaasong Zuyeri
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.59018
Abstract: Termites build their habitat in the form of anthills or termitaria or termite mounds which are characterised by soil of clayey texture. This paper investigated the relative grain size from the base, middle and near the peak of three anthills located 20 km west of Winneba near the Apam-Winneba highway in Ghana and also correlated their elemental compositions. The results showed significant grain size gradation of soils which range from <0.075 mm to 2 mm such that coarse grains occurred at the base while finer fractions were at higher parts of the anthills. Major oxides (wt. %) showed that SiO2 (51.70 - 60.24) was positively correlated with total FeO (12.22 - 15.24), Al2O3 (22.18 - 28.88), MnO (0.08 - 0.09), and K2O (0.4 - 0.61). However, as K2O decreased with height on anthill, SiO2, total FeO and Al2O3 increased. Probably soils used to construct these anthills were derived from different rock types and/or the termites were selective in the use of soils rich in silica or iron oxide.
Complement activation in Ghanaian children with severe Plasmodium falciparum malaria
Gideon K Helegbe, Bamenla Q Goka, Joergen AL Kurtzhals, Michael M Addae, Edwin Ollaga, John KA Tetteh, Daniel Dodoo, Michael F Ofori, George Obeng-Adjei, Kenji Hirayama, Gordon A Awandare, Bartholomew D Akanmori
Malaria Journal , 2007, DOI: 10.1186/1475-2875-6-165
Abstract: The direct Coombs test (DCT) and flow cytometry were used to investigate the mean levels of RBC-bound complement fragments (C3d and C3bαβ) and the regulatory proteins [complement receptor 1 (CD35) and decay accelerating factor (CD55)] in children with discrete clinical forms of P. falciparum malaria. The relationship between the findings and clinical parameters including coma, haemoglobin (Hb) levels and RD were investigated.Of the 484 samples tested, 131(27%) were positive in DCT, out of which 115/131 (87.8%) were positive for C3d alone while 16/131 (12.2%) were positive for either IgG alone or both. 67.4% of the study population were below 5 years of age and DCT positivity was more common in this age group relative to children who were 5 years or older (Odds ratio, OR = 3.8; 95%CI, 2.2–6.7, p < 0.001). DCT correlated significantly with RD (β = -304, p = 0.006), but multiple regression analysis revealed that, Hb (β = -0.341, p = 0.012) and coma (β = -0.256, p = 0.034) were stronger predictors of RD than DCT (β = 0.228, p = 0.061). DCT was also not associated with IVH, p = 0.19, while spleen size was inversely correlated with Hb (r = -402, p = 0.001). Flow cytometry showed similar mean fluorescent intensity (MFI) values of CD35, CD55 and C3bαβ levels on the surfaces of RBC in patients and asymptomatic controls (AC). However, binding of C3bαβ correlated significantly with CD35 or CD55 (p < 0.001).These results suggest that complement activation contributed to anaemia in acute childhood P. falciparum malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement regulatory proteins, CD35 and CD55 and malarial anaemia. These findings suggest that complement activation could also be involved in the pathogenesis of RD but larger studies are needed to confirm this finding.The mortality associated with malaria largely occurs in children as a result of complication
Indoor Tanning, Sunbathing, and the Hazard of Skin Cancer: The Effect of the Tan Tax  [PDF]
Gideon Yaniv, Erez Siniver
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.51007
Abstract: In July2010, a10 percent federal sales tax on indoor tanning, known as the tan tax, went into effect. Applauding the imposition of the new tax, the American Academy of Dermatology (AAD) foresees that by discouraging indoor tanning, the tan tax will significantly reduce the risk of skin cancer and consequently the future costs of its treatment, currently amounting to $1.8 billion each year. Recognizing, however, that an alternative to indoor tanning may be the riskier practice of sunbathing, the present paper offers a rational-choice model for addressing the individual’s indoor and outdoor tanning decisions, which is applied to examining his or her response to the imposition of a tan tax and the consequent effect on the hazard of developing skin cancer. The paper challenges the AAD’s forecast, identifying conditions under which a tan tax will rather exacerbate the hazard of skin cancer.
The Game of Monetary Policy, Inflation and Economic Growth  [PDF]
Gladys Wauk, Gideon Adjorlolo
Open Journal of Social Sciences (JSS) , 2019, DOI: 10.4236/jss.2019.73022
Abstract: Ghana has been confronted with series of economic problems to the extent of calling on the IMF for a bailout after every eight years. This situation has persisted in spite of various monetary authority stabilization policies. This paper therefore focuses on investigating the games of monetary policy, inflation and economic growth of the Ghanaian economy for the period of 1982-2017. Using Autoregressive Distributed Lag (ARDL) to cointegration model, it was revealed from the study that in the long run interest rate significantly influences economic growth but in a negative direction, implies that a higher interest rate has the tendency to restrained economic growth and inflationary pressures. In relation to exchange rate, the long run result indicates an insignificant negative effect on economic growth. The general results suggest that macroeconomic variable which influences economic growth is interest rate and exchange rate. This is evidence that macroeconomic instabilities have significant effect on economic growth. This therefore calls for fiscal discipline and autonomy power to the Bank of Ghana with less interreference from the government to enable the smooth implementation of monetary policies without any string of politics attached.
Acute effects of consumption of energy drinks on intraocular pressure and blood pressure
Ilechie AA, Tetteh S
Clinical Optometry , 2011, DOI: http://dx.doi.org/10.2147/OPTO.S16229
Abstract: cute effects of consumption of energy drinks on intraocular pressure and blood pressure Original Research (4965) Total Article Views Authors: Ilechie AA, Tetteh S Published Date April 2011 Volume 2011:3 Pages 5 - 12 DOI: http://dx.doi.org/10.2147/OPTO.S16229 A Alex Ilechie, Sandra Tetteh Department of Optometry, University of Cape Coast, Ghana Background: Energy drinks contain a wide variety of ingredients including caffeine, for which there have been conflicting reports regarding its effects on intraocular pressure (IOP) and blood pressure. The aim of this study was to investigate the acute effects of an energy drink (Red Bull ) on the IOP and blood pressure of healthy young adults. Methods: Thirty healthy university students of either gender, aged 18–30 (mean 23.20 ± 2.81) years were randomly selected to participate in this study. The subjects were randomly divided into two groups (experimental and control) and were asked to abstain from caffeine for 48 hours prior to and during the study. Baseline IOP and blood pressure were measured. The experimental group (n = 15) consumed one can of the energy drink (containing 85 mg of caffeine in 250 mL) and measurements were repeated at 30, 60, and 90 minutes, while the control group drank 250 mL of water and were tested over the same time period. Results: When compared with baseline, a significant decrease (P < 0.05) in mean IOP at 60 and 90 minutes was observed in the experimental group. There was no corresponding change in systolic or diastolic blood pressure. Conclusion: Our results suggest that energy drinks (ie, Red Bull) produce a significant reduction in IOP but have no effect on blood pressure. These findings may be interpreted as reflecting the effect of the combination of caffeine and taurine in the Red Bull energy drink. This effect may result from the known hypotensive effect of taurine, and warrants further study.
Market Structure and Competition in the Ghanaian Cocoa Sector after Partial Liberalization
Benjamin Tetteh Anang
Current Research Journal of Social Science , 2011,
Abstract: The study looked at market structure and competition in Ghana cocoa sector after the introduction of partial reforms in cocoa marketing. The study involved 80 randomly selected cocoa farmers from four communities in Bibiani-Anhwiaso-Bekwai District, Western Region, Ghana. Secondary data were collected from the Head Office of Ghana Cocoa Board, Accra. Results showed that more firms have entered the industry since the introduction of competition resulting in an increase in industry competition and a loss of market share of the top buyers. The cocoa sector experienced a gradual decrease in market concentration. The concentration ratios revealed that a few large firms continue to dominate the market. However, there are no monopolistic tendencies in the Ghanaian cocoa sector and firms are free to compete with each other for market shares. The absence of price competition has resulted in an interesting marketing scenario with producer-buyer loyalty playing a key role in gaining market share. Licensed Buying Companies have found ways to ensure that farmers sell to them alone and these include prompt payments, social involvement in farmers communities, and provision of services, incentives, subsidized inputs and credit. Farmers in turn maintain loyalty to buyers who provide certain incentives and cash rewards. More benefits accrue to farmers now than the period before the reforms. It was concluded that the market structure in Ghana cocoa sector will remain unchanged for some time if the government of Ghana maintains its partial liberalization policy.
Acute effects of consumption of energy drinks on intraocular pressure and blood pressure
Ilechie AA,Tetteh S
Clinical Optometry , 2011,
Abstract: A Alex Ilechie, Sandra TettehDepartment of Optometry, University of Cape Coast, GhanaBackground: Energy drinks contain a wide variety of ingredients including caffeine, for which there have been conflicting reports regarding its effects on intraocular pressure (IOP) and blood pressure. The aim of this study was to investigate the acute effects of an energy drink (Red Bull ) on the IOP and blood pressure of healthy young adults.Methods: Thirty healthy university students of either gender, aged 18–30 (mean 23.20 ± 2.81) years were randomly selected to participate in this study. The subjects were randomly divided into two groups (experimental and control) and were asked to abstain from caffeine for 48 hours prior to and during the study. Baseline IOP and blood pressure were measured. The experimental group (n = 15) consumed one can of the energy drink (containing 85 mg of caffeine in 250 mL) and measurements were repeated at 30, 60, and 90 minutes, while the control group drank 250 mL of water and were tested over the same time period.Results: When compared with baseline, a significant decrease (P < 0.05) in mean IOP at 60 and 90 minutes was observed in the experimental group. There was no corresponding change in systolic or diastolic blood pressure.Conclusion: Our results suggest that energy drinks (ie, Red Bull) produce a significant reduction in IOP but have no effect on blood pressure. These findings may be interpreted as reflecting the effect of the combination of caffeine and taurine in the Red Bull energy drink. This effect may result from the known hypotensive effect of taurine, and warrants further study.Keywords: acute effect, intraocular pressure, blood pressure, glaucoma, caffeine, taurine
Unification, the Big Bang, and the Cosmological Constant
Edward Tetteh-Lartey
Physics , 2006,
Abstract: The two major goals in fundamental physics are: 1) Unification of all forces incorporating relativity and quantum theory, 2) Understanding the origin and evolution of the Universe as well as explaining the smallness of the cosmological constant. Several efforts have been made in the last few decades towards achieving these goals with some successes and failures. The current best theory we have for unification of all forces is Superstring/M Theory. However current evidence suggests our Universe is flat and accelerating. A Universe with a positive cosmological constant will have serious implications for string theory since the S-Matrix cannot be well defined and Superstring/M Theory is only formulated in flat Minkowski background. Holographic principle provides a way out as shown by the AdS/CFT and dS/CFT correspondence, but it remains to be proved if it is valid for our non-conformal, non-supersymmetric Universe. Aside from the issue of defining M-Theory in a de Sitter background, why the cosmological constant is so small remains puzzling and needs to be understood. The ``cosmological constant problem'' has brought physics to a standstill towards any major development and remains currently the most disturbing issue. Conventional big bang cosmology has not yet produced a satisfactory explanation of the small value of the cosmological constant. An attempt by SuperString/M Theory in this direction is given by the Ekpyrotic/Cyclic model. The aim of this review is not to introduce any new concepts not already known, but give an overview of current state of affairs in high energy physics, highlighting some successes and failures and making some few suggestions on areas to focus to resolve some of these outstanding issues.
Microbiological Quality of Chicken Sold in Accra and Determination of D10-Value of E. coli  [PDF]
Abraham Adu-Gyamfi, Wellington Torgby-Tetteh, Victoria Appiah
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.35094
Abstract: Chicken is an excellent source of good quality protein, but it is highly susceptible to microbial contamination and often implicated in food borne disease. The microbiological quality of chicken at different retail outlets (supermarkets, local markets and farms) in Accra was investigated, and D10-values of E. coli in refrigerated and frozen retailed chicken was determined. The microbiological quality of chicken was studied by analyzing 27 chicken thigh samples collected from the retail outlets. D10-value of Escherichia coli was determined by using a linear regression model after gamma irradiation of inoculated chicken samples with doses of 0, 150, 300, 450, 600, 750 and 900 Gy. Mean total viable counts for the supermarkets, local markets and farms were 6.46, 6.91 and 6.57 log10 cfu/g respectively. Mean total coliform counts for the supermarkets, local markets and farms were 3.80, 3.46 and 3.14 log10 cfu/g respectively and the mean S. aureus counts were also 2.32, 2.28 and 2.70 log10 cfu/g respectively. There were no significant differences (p > 0.05) between the mean total viable count, total coliform counts and S. aureus count for the supermarkets, local markets and the farms. Mean counts of E. coli detected at the supermarket, local markets and farms were 1.27, 2.59 and 2.74 log10 cfu/g respectively. Salmonella spp. was detected in 2 out of the 27 samples. Fifty-two percent and 70% of samples respec-tively had total viable counts and total coliform counts within the microbial safety standards. Mean D10E. coli were 0.22 and 0.32 kGy in refrigerated and frozen chicken respectively. Presence of pathogenic bacteria in fresh chicken sold in some retail outlets in Accra was confirmed. Low D10-values of E. coli especially under refrigerated conditions suggest susceptibility to low dose irradiation and possibility of controlling spoilage and pathogenic microflora of fresh poultry.
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